• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The invention relates to a screw and ball nut mechanism comprising a screw (14) and a nut (12) with threads, the nut cooperating with the screw (14) via balls (28) which can circulate in a raceway (26) formed by the threads (22, 24) of the screw and the nut opposite, the nut being furthermore provided with at least one insert (32) for recirculation inserted from an external face ( 18) of the nut, in at least one housing (30), cylindrical, passing through the nut of the outer face (18) of the nut (12) to the thread (22) of the nut, the recirculation insert (32) having a first end (34) with a ball transfer groove (36) facing the screw (14). According to the invention: - the mechanism comprises a retaining insert holding body (32), configured to hold the recirculation insert in the housing, - the recirculation insert (32) has a second end with a bearing shoulder on a bearing surface of the nut (12), - the second end of the recirculation insert (32) comprises an orientation pin (38) having a predetermined angular position and fixed relative to the ball transfer groove (36), the orientation pin cooperating with one of at least one guide relief (44) of the holding body, and an impression (45) of the nut, for securing a orienting the recirculation insert (32) in the housing, the orientation of the insert being fixed so that the transfer groove (36) is fitted to the raceway.
    公开号:FR3028714A1
    申请号:FR1461401
    申请日:2014-11-25
    公开日:2016-05-27
    发明作者:Roger Pellenc；Philippe Gilbert
    申请人:Pellenc SAS；
    IPC主号:
    专利说明:

    [0001] i Screw mechanism and ball nut. TECHNICAL FIELD The present invention relates to a ball screw-nut mechanism and in particular to such a mechanism, of reduced dimensions and weight, suitable for use in power tools, such as electric shears or electric shears, by example. The invention can also find applications in the field of machine tools, the aeronautical field, the actuators, and more generally in any type of mechanical device requiring a transformation of a rotational movement into a translation movement or vice versa. STATE OF THE PRIOR ART Systems making it possible to transform a rotational movement into a translational movement, or a circular movement into a linear movement, often use screw and ball nut devices, which make it possible to transform the movement with a very good efficiency. They generally consist of a helical screw screw with circular or gothic profile, a nut including a thread provided with the same type of profile, and calibrated diameter balls circulating in a raceway constituted by the conjunction of the thread of the screw and that of the nut, in which the balls transmit the forces between the screw and the nut, almost without friction. One of the problems to be solved for these devices is the recycling of the balls in the raceway. Indeed, when the screw rotates relative to the nut, the balls advance in their raceway. To prevent the balls from coming out of the space between the screw and the nut during operation, they are returned to their starting point by a recycling device after having traveled one or more successive turns in the raceway. This recycling device incorporates a complementary trajectory portion of the balls, hereinafter referred to as a transfer groove, which separates the balls from their raceway in order to force them to circulate over the outside diameter of the screw and then to rejoin the track in a cyclic path, avoiding them to escape from their grip between the screw and the nut. The transfer groove takes the form of a channel for guiding the trajectory of the balls, which channel may be tubular in shape and thus completely surround the balls around their path. In the transfer groove of the recycling device, the balls do not participate in the transmission of the force between the screw and the nut. The trajectory followed by the balls during the operation of the screw-nut IO system is thus a closed path consisting of a helical raceway at one or more turns and completed by the transfer groove of the recycling device. Several raceways can thus be defined in the same screw-nut ball system, requiring the same number of recycling devices.
    [0002] The new generations of screw-and-ball screw systems favor recycling devices on a lathe, thus limiting the number of balls that do not contribute to the force transmitted between the screw and the nut, but also the complexity of achieving the transfer groove complementary to each raceway and, therefore, the cost of the device. These ball-and-recycle screw-nut systems also limit the risk of ball lock failure in the recycling device. Indeed, the recycling devices on several turns have long and complex transfer grooves to achieve, for example by incorporating tubular parts, to transport the balls above the intermediate laps of the ball raceway so as not to disrupt their circulation in the raceway formed by these intermediate turns. However, these ducts can be easily obstructed by dust or debris transported by the balls and agglomerated with any lubricants present in the screw-nut system. The recycling devices generally comprise recirculation inserts of plastic or metal alloy with low friction and positioned in a housing formed in the nut between its outer surface and its inner surface. These recirculation inserts each incorporate a transfer groove at a first end located at the threads of the nut to complete the raceway of the balls. The main problem then lies in fixing the inserts constituting the recycling device. There are two categories of recycling devices that respond to this problem: recycling devices assembled from the inside of the nut and recycling devices assembled from the outside of the nut. An internally assembled recycling device is described, for example, in FR2703122. The recirculation insert of this recycling device is positioned in its housing by the inside of the nut. It has two legs coming to be housed on either side of its housing when they enter the raceway in contact with the nut, said tabs ensuring in this position the smooth operation of the transfer groove in continuity with the raceway of the balls by locking the orientation and the axial positioning of the recirculation insert. A difficulty likely to be encountered with such a recycling device is however related to the assembly of the parts, in particular for nuts of small diameter and of great length. Indeed, it is necessary that each recirculation insert with its positioning tool can enter the threaded hole of the nut before being positioned facing its housing to be inserted with a precise orientation. This operation requires complex tools, and may be impossible, since the diameter of the threaded hole is small, for example less than the size of a finger. An externally assembled recycling device is described, for example, in FR2045496. It does not present the mounting difficulties mentioned above. However, the realization here housing in the elliptical shaped nut to fix the orientation of the transfer groove is difficult and expensive to achieve. An assembly recycling device from the outside is still described in EP0957294. This device, however, requires a particular tool 30 to introduce the recirculation inserts and they are not held by the outside of the nut to compensate for the forces generated in the axis of the housing on the recirculation insert during the passage of the balls in the transfer groove. In case of heavy load supported by the screw-nut system, the balls generate efforts always greater in this axis. If these efforts are not sufficiently taken up by the size of the tabs, they may disengage from their housing or generate deformations of the transfer groove penalizing the performance of the screw-nut system. The size of the tabs is further limited by the method of placing the insert, thereby limiting the support effort bearable by the insert in its housing. Thus, in these ball screw-nut systems, the recirculation inserts 10 are generally held in the nut housing by means such as glue, locking screw, spring ring, or the like and lock the orientation of the transfer groove by complex combined shapes of the recirculation insert combined with the complementary shape of its housing. These means increase the complexity of producing both the housing of the nut but also that of the recirculation inserts and their holding device. DESCRIPTION OF THE INVENTION The invention aims to obtain the advantages of the various solutions presented above, while simplifying the machining of the nut and decreasing the mounting time of the screw-nut assembly. The invention also aims to guarantee a simple and precise maintenance and orientation of each transfer groove even in case of heavy load transmitted by the screw-nut system and without significant degradation of the efficiency of said system. To achieve these aims, the invention proposes a screw and nut mechanism with 25 balls comprising: a screw and a nut with threads, the nut cooperating with the screw via balls that can circulate in a race formed by the threads of the screw and nut facing, the nut being further provided with at least one recirculation insert inserted from an outer face of the nut, in at least one cylindrical housing, passing through the nut of the outer face of the nut to the thread of the nut, the recirculation insert having a first end with a ball transfer groove turned towards the screw. According to the invention: the mechanism comprises a retention body of the recirculation insert, configured to hold the recirculation insert in the housing of the nut. The main purpose of the holding body is to hold the recirculation insert in its housing. The holding body is, for example, an additional part of the mechanism which surrounds and supports the nut.
    [0003] Furthermore, and still according to the invention: - the recirculation insert has a second end with a bearing shoulder on a bearing surface of the nut, - the second end of the recirculation insert comprises an orientation pin having a predetermined angular position and fixed with respect to the ball transfer groove. The orientation pin cooperates with at least one guide relief of the holding body, or an impression of the nut, to fix an orientation of the recirculation insert in the housing. The orientation of the recirculation insert in the housing is set such that the transfer groove is adjusted to the raceway. The ball screw-nut mechanism may comprise in particular a plurality of recirculation inserts received respectively in a plurality of cylindrical housings. The screw of the ball screw-nut mechanism may have a helical thread 25 in the form of a groove or groove with a circular or gothic profile. To the thread of the screw corresponds an internal thread of the nut, which faces it. The two nets preferably have the same profile and have an identical pitch. They constitute a raceway which receives a plurality of balls. The balls are able to circulate, almost without friction, in the raceway, during the relative rotation between the screw and the nut. As indicated in the introductory part, the balls transmit in this rolling path the forces of movement 5 between the screw and the nut. The first end of each recirculation insert has a bead transfer groove locally modifying the path of the latter. The transfer groove circulates the balls above the thread of the screw to bring them upstream of the raceway. This defines a cyclic trajectory of the balls. The insert can be adapted to recirculation over several laps of the ball path. Preferably the recirculation is however made on a single turn. The proper functioning of the recirculation of the balls requires a precise positioning in height of the insert. It also requires a precise orientation of the recirculation insert in its housing so that the transfer groove can accompany the balls in their path change from the raceway, with the minimum of constraints. The recirculation insert has indeed a role of extraction of the ball raceway at a first end of the transfer groove. The recirculation insert forces the balls to disengage from the raceway and pass over the thread of the screw through the transfer groove. The balls join the raceway at the second end of the transfer groove and behind the location of their extraction. The balls thus cycle cyclically the raceway and the transfer groove as the relative movement between the screw and the nut does not reverse. In case of reversal of the direction of the relative movement, for example in the case of a reversal of the direction of rotation of the screw, the balls travel the cyclic path in the opposite direction. The output end of the transfer groove then becomes the input end which extracts the balls of the raceway. During their travel, the balls exert on the recirculation insert efforts, oriented in the alignment of the raceway, and especially when they come against the first end of the transfer groove, that is to say the entrance end. The balls also exert radial forces on the insert in its housing, from the inside of the nut to the outside of the nut. The radial forces are transmitted to the body holding the recirculation inserts. This prevents the recirculation inserts from coming out of their housing towards the outside of the nut. The raceway of each ball may comprise one or more turns, a raceway on a single turn is however preferred. Thus the nut may preferably comprise a plurality of recirculation inserts received in as many slots. The number of recirculation inserts is adapted to the length of the nut and the number of balls necessary for the proper operation of the screw-nut assembly. The recirculation inserts and their housings are preferably uniformly angularly distributed around the nut to distribute symmetrically the forces of the balls during passage through the transfer grooves.
    [0004] Thus, the holding body may also comprise a plurality of guide reliefs, with uniform angular distribution, cooperating with a plurality of orientation pins of the recirculation inserts. In such a configuration, the recirculation inserts may be spaced axially respectively by a distance corresponding to a ball race in the raceway or a multiple of the number of ball turns. The height positioning of each recirculation insert is ensured by its shoulder which bears on a bearing surface of the nut. The shoulder may be formed by the orientation pin, which then projects radially relative to the body of the insert. The shoulder may also be distinct from the orientation tenon. The bearing surface for the shoulder may simply be the outer face of the nut. It may also be a support pad at the bottom of a depression made in the nut around the housing for the insert. Thus, the height positioning of the insert is indexed relative to the outer face of the nut or relative to the bottom of the depression. The height of the insert in its housing and the length of the body of the insert thus make it possible to precisely fix the radial position of the transfer groove with respect to the raceway, and in particular with respect to the thread of the nut.
    [0005] It should be noted in this regard that the housing, which extends from the outer face of the nut to the thread of the nut, is preferably a radial housing, for reasons of ease of machining. The depression formed around the housing may be a recess extending in the thickness of the nut and receiving the shoulder of the insert. It makes it possible to limit or avoid exceeding the insert 10 with respect to the nut. When a depression is formed in the nut it can also act as a fingerprint, cooperating with the orientation pin to fix the orientation of the recirculation insert in its housing. An imprint of suitable shape, for example complementary to the shape of the orientation pin, can indeed serve to block the rotation of the insert in its housing and in a position in which the transfer groove is adjusted to the rolling, in the way allow the passage of balls. The post and the footprint may be, for example, polygonal, and preferably square. When the shape of the post and the footprint is an axially symmetrical shape, the post is preferably off-axis with respect to the insert, and the impression is off-axis with respect to the housing. In other words, the axis of symmetry of the post and the cavity are slightly offset respectively with respect to the axis of symmetry of the insert and the axis of the housing. The offset is a key at the time of introduction of the recirculation insert in its housing.
    [0006] Depending on the shape of the impression, it may be formed in the nut by molding, machining or forging. The impression can also be a groove cooperating with an elongate orientation pin. Its width is then adjusted to that of the tenon. The impression can still be a circular depression, for example the countersink mentioned above.
    [0007] Indeed, in a particular embodiment of the mechanism the recirculation insert may have a circular shoulder forming the orientation pin and cooperating with a corresponding circular imprint formed in the nut and depression relative to the outer face of the nut. The circular imprint and the circular shoulder are then respectively off-axis with respect to an axis of the housing of the insert and with respect to an axis of the recirculation insert, so as to lock the rotation of the recirculation insert. in his dwelling. Preferably, the orientation body forms with the impression a sliding fit. According to another possibility of implementing the invention, briefly mentioned above, the orientation of the transfer groove with respect to the raceway of the balls can also be fixed by the orientation pin in cooperation with the associated guide relief of the holding body. The holding body, received on an outer face of the nut, may advantageously comprise several guide reliefs cooperating with a plurality of orientation pins present on the outer face of the nut. Indeed, and as mentioned above, the mechanism preferably comprises a plurality of recirculation inserts, and each insert is provided with an orientation pin. The orientation pin of the insert is received, guided and oriented by the relief of the holding body. This therefore allows to guide the recirculation insert 20 and its transfer groove, thanks to the freedom of rotation of the insert in its housing. The guide relief and the tenon preferably have complementary shapes. For example, the relief may be in the form of one or more ribs on which can slide a complementary impression of the orientation pin. Conversely, the orientation pin may also be in the form of a small rail which slides in a relief of the holding body in the form of a depression guide groove. The orientation pin locks the rotation of the recirculation insert when it is engaged in the groove or the corresponding rib of the holding body. The orientation of the guide relief is fixed relative to the holding body, and the position of the holding body on the nut is determined by the outer face of the nut which receives the holding body and on which the body of the maintenance is adjusted. Furthermore, the orientation pin and the transfer groove are fixed on the recirculation insert, and preferably formed in one piece with the body of the recirculation insert. Thus the relative orientation of the transfer groove can be fixed by adjusting one or more of the orientation of the guide relief, the orientation of the post relative to the body of the insert and the orientation of the groove. transfer on the body of the insert. The guide relief of the holding body is preferably selected parallel to the axis of the screw and the nut, for reasons of ease of assembly. The orientation of the transfer groove is preferably determined during the manufacture of the insert. Indeed, the insert can be manufactured by molding metal 10 or plastic. Thus the fixing of the relative orientation of the transfer groove, and / or that of the orientation pin, takes place by molding and is particularly easy. The holding body also has the function of cooperating with the upper face of the recirculation insert, which may be formed by the upper face 15 of the orientation pin. Indeed, and as mentioned above, the holding body bears on the recirculation inserts to prevent them from coming out of their housing under the effect of the stresses exerted by the balls. This holding, combined with the support of the shoulder on the nut, ensures precise height positioning of the recirculation insert in its housing and therefore the height of the transfer groove relative to the raceway of the balls. and the screw. When the shoulder of the recirculation insert is protruding on the outer face of the nut, the retaining body may also have grooves or lands allowing the passage of the portion of the shoulder which is projecting. In a preferred embodiment, the post can directly form the shoulder. it is, for example, a rail that protrudes from the body of the recirculation insert, and whose projecting portion is supported on the outer face of the nut when the body of the insert recirculation is introduced into its housing. Although other forms may be retained, the recirculating insert preferably has a generally cylindrical body that can be introduced with reduced clearance in the housing. The insert has a freedom of rotation in the housing when the tenon is not engaged. According to a particular embodiment of the recirculation insert, it may still have at least one lug, and preferably two symmetrical lugs 5 formed in the vicinity of the bead transfer groove. The legs extend in the raceway towards the screw. They each have a stop edge forming a barrier to the flow of balls in the raceway, so that the balls moving in the raceway come to butter against the stop edge. This facilitates their extraction from the rolling path and their routing to the transfer groove. The tabs are an extension of the edges of the transfer groove. Although the tabs extend in the raceway sufficiently to collect the balls, they are preferably designed to not completely occupy the raceway. It is indeed preferable that the lugs do not come into contact with the screw, so as to avoid friction degrading the performance of the screw-nut system. When the loads supported by the ball screw-nut mechanism are large, the balls also exert a significant effort on the stop edges of the tabs. In order to better contain this force, the tabs may have a counter opposite the stop edge of the balls, the buttress protruding radially on the body of the recirculation insert, and extend in the raceway. The extension in the raceway increases the volume of the buttress and therefore its ability to consolidate the leg. The buttress, or at least the portion of the buttress that extends into the raceway is also designed to not completely occupy the raceway so as not to generate friction and so as not to interfere with the ride. orientation of the recirculation insert. The recirculation insert may include at least one recess or slot for radial retraction of the tab or tabs. By radial retraction of the tab is meant a movement moving the tab towards the axis of the recirculation insert, so that the tab, and in particular the abutment mentioned above, no longer constitutes a pawl. obstacle to the introduction of the recirculation insert in its cylindrical housing. For this purpose, the tab may be flexibly connected to the body of the insert with an amplitude of flexion towards the retracting recess equal to or slightly greater than a length of the protruding buttress so as to retract it. fully. The possibility of radial retraction of the tabs, and in particular of their protruding buttress, makes it possible to facilitate the introduction of the recirculation insert into its cylindrical housing while maintaining an adjustment of the body of the insert on the diameter of the housing. . It also keeps the possibility of rotation of the body of the insert in the housing before the orientation pin does not come to lock the rotation. The flexible nature of the link between the lug and the body of the insert allows the buttresses to automatically extend into the raceway as soon as the recirculation insert is in place.
    [0008] The retraction recess is, for example, a slot bisecting the insert, extending from the first end, that is to say the end bearing the transfer groove, toward the second end. bearing the tenon. The retraction slot extends over part of the height of the insert. In a particular embodiment of the insert, the retraction slot passes through the transfer groove and forms two symmetrical legs which each carry a tab. The height of the slit determines the length of the legs. This is adjusted to obtain the flexibility necessary for the retraction of the legs. The retraction slot has a width smaller than the diameter of the balls, to prevent balls from getting caught or getting into it.
    [0009] Bending legs may be provided to connect the tabs to the body of the recirculation insert so as to promote radial retraction of the tabs. In one of its main applications, the invention relates to a portable power tool such as a pruner or sheet shears, comprising a movable blade, a rotary motor, a moving part for driving the movable blade, driven by the motor, and a ball screw-nut mechanism as described. The nut of the screw-nut mechanism is connected to the movable blade drive part 3028714 13 and the screw is connected to the motor. The holding body may be a plastic or metal ring fitted to the nut. It can also be constituted by a drive member of the nut by a motor or geared motor assembly, or by a fixed member linked to the structure of the tool incorporating the screw-nut system.
    [0010] When the holding body is fixed or linked to the tool structure, the ball nut can be slidably mounted in the holding body during operation of the screw nut system. In this case, the orientation pins may be designed to slide also relative to the reliefs of the holding body. The screw of the ball screw-nut mechanism may constitute an extension of the motor shaft or be connected to the motor shaft via a gearbox or a suitable coupling mechanism. BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features and advantages will become more apparent from the following description and drawings in which: FIG. 1 is an exploded view of a ball screw-nut mechanism according to the invention. FIG. 2 is a perspective view of a holding body of the ball screw-nut mechanism of FIG. 1. FIG. 3 is a partial cutaway showing the assembly of the ball screw-nut mechanism. FIG. 4 is an exploded ball screw-nut mechanism. Figure 5 is a longitudinal section of the nut of Figure 3 illustrating recirculation of the balls.
    [0011] Figure 6 is a longitudinal section of the nut of Figure 3 provided with the screw of the ball screw-nut mechanism. Figure 7 is a cross section of a portion of the nut showing a detail of the establishment of a recirculation insert.
    [0012] Figure 8 is a cross-section of a portion of the ball screw-nut mechanism around a recirculation insert. Figure 9 is a section of a portion of the ball screw-nut mechanism passing through a buttress of a recirculation insert. Figure 10 is a perspective of a recirculation insert.
    [0013] Figure 11 is a partial section of an electric pruner using a ball screw-nut mechanism according to the invention. FIG. 12 is an exploded view of a screw-nut mechanism according to the invention, illustrating a variant of the mechanism of FIG. 1. Detailed description of embodiments of the invention.
    [0014] Reference is made to the drawings to describe an interesting example, although in no way limiting, of producing a ball screw-nut mechanism according to the invention. Identical or similar parts of the different figures are marked with the same reference numerals so that reference can be made from one figure to the other. The various figures are shown in free scale. The screw-nut mechanism ball 10 of Figure 1 comprises a nut 12 received on screws 14. The nut and the screw are preferably metal. When the screw and the nut are assembled, the screw passes through a threaded hole 16 of the nut 12 provided with an internal thread 22. The internal thread of the nut 12 is better visible in FIGS. 5 and 7. The pitch of the inner thread 22 of the nut corresponds to the pitch of a thread 24 made on the screw. When the nut 12 and the screw 14 are assembled, the threads 22 and 3028714 of the nut and the screw are mutually opposite each other and form a rolling path 26, visible in FIGS. 6, 8 and 9. Runway 26 receives a plurality of balls 28. The balls 28, whose diameter is adapted to that of the threads, maintain the nut in a concentric position on the screw, when the screw 5 and the nut are assembled. They transmit the efforts of the movement of the screw towards the nut, and vice versa. The balls are preferably made of steel. The rotation of the screw 14 may be clockwise or counterclockwise, respectively causing a translation of the nut 12 in one direction or the other along the axis of the screw. In the illustrated embodiment, the nut has a cylindrical outer surface 18. It is noted that the outer surface is not necessarily cylindrical. The nut may in fact have other shapes, for example a hexagonal shape. A plurality of housings 30, in the form of radial bores, are formed in the nut 12, with a uniform angular distribution. The bores 15 have a chamfer 31. The housings 30 pass through the nut from the outer face 18 to the inner thread 22. Each housing 30 is intended to receive a recirculation insert 32. As shown in FIGS. 1, 7, 10 and 12, and in the particular example described, the inserts 32 have a generally cylindrical shape with a first end 34, facing the screw 14, and provided with a transfer groove 36. A second end, opposite to the first end, is provided with an orientation pin 38. The circulation insert, and the orientation pin, preferably formed in one piece, may be metal or plastic. Figure 8 shows that the recirculation insert is received with reduced clearance in its housing. Figures 1, 3, 4, 5, 6 and 12 show that the orientation pin 38 forms a shoulder which bears on a bearing surface of the nut. In the example illustrated in FIGS. 1 to 6, the bearing surface is formed by the outer face 18 of the nut. In the example illustrated in FIG. 12, the bearing surface is formed by a face of a cavity 45 made in the nut. The support of the shoulder makes it possible to fix the extension of the recirculation insert in the housing 30. As is still shown in FIGS. 5 to 8, the length of the recirculation inserts is fixed so that the groove transfer 36 comes to connect to the raceway 26 of the balls when the shoulder formed by the stud 38 bears on the bearing surface of the nut.
    [0015] A transfer groove 36 of the recirculation inserts is best seen in FIG. 5 which illustrates the recirculation of the balls 28. FIG. 5 is a section of the nut 12 into which the screw has been removed. It shows in particular the ends of four recirculation inserts in position in the nut. For the sake of clarity the screw is removed and the balls are shown only for two paths of balls 10 in the raceway. It can be seen that the balls 28 pass through the transfer groove 36 of the recirculation inserts of a row of the raceway 26, or a row of the thread 22 of the nut, to the next or preceding row, according to the direction of rotation. The recirculation of the balls is also illustrated in FIG. 6 which is a section of the nut 12 into which the uncut screw 14 passes. It can be observed that the balls travel along a path along a raceway 26 which goes respectively from one row of the threads of the screw and the nut to the next row. The balls 28 are then extracted from the raceway by the recirculation insert and pass into the transfer groove 36 of the recirculation insert, above the thread 24 of the screw 14. The balls are finally reintroduced into the race 26 to the previous or next rank of the net, according to the direction of rotation. The two bead paths shown use a first recirculation insert upstream of the section plane that is not shown, and a second recirculation insert positioned in the section plane. The beads are not shown in the other 25 paths for the sake of clarity. Returning to FIG. 1, it may be noted that the ball screw-nut mechanism has a holding body 40, preferably made of plastic, intended to cover the nut 12. The holding body is more precisely a sleeve that comes into contact with the outer face 18 of the nut. In the illustrated example, where the nut 12 is generally cylindrical in shape, the holding body also has a generally cylindrical bore with a diameter adjusted to that of the nut. Other complementary forms of the nut and the holding body can be envisaged. As shown in Figure 3, an essential function of the holding body is to maintain the recirculation inserts 32 in their housing. The holding body is in fact resting on the recirculation inserts 32 so as to press their shoulder against the nut. FIG. 2 shows that the internal face of the bore 42 of the holding body 40 has guide reliefs 44. In the example shown, it is a question of grooves which extend parallel to the axis of the bore.
    [0016] The guiding relief 44 has a shape complementary to the orientation pins 38. In the illustrated example, the orientation pins have an oblong shape, and the grooves of the guide relief have a width corresponding to that of the tenons. Figure 3 shows the mechanism of Figure 1 assembled. The nut 12 is inserted into the holding body 40. It can be seen that the orientation pins 38 are received and oriented in the grooves of the guide relief 44. This corresponds to the second function of the holding body which is to fix and maintain the orientation of the recirculation inserts. The precise orientation of the recirculation inserts is essential because it makes it possible to adjust the orientation of the transfer groove with respect to the bead path. A guide relief may be provided for each recirculation insert. It is also possible to provide that the same guide relief cooperates with the tenons of several recirculation inserts aligned along the axis of the nut. It can be seen in Figures 1 and 4 that the orientation pins 38 have a slightly tapered end. This makes it possible to locate briefly the orientation of the recirculation inserts at the time of their introduction in their housings. In addition, the slightly tapered end facilitates the introduction of the tenons in the guide relief 44 at the time of assembly. When the guide pins engage the guide relief, the orientation of the inserts automatically adjusts to the guide relief thanks to the freedom of rotation of the recirculation inserts 32 in their 3028714 18 slots 30. However as soon as the guide pins 38 engage with the guide relief, the rotation of the inserts is locked. Figures 1, 3, 4, 5 and 12 still show a fixing bore 50 on the nut 12. The bore 50, radial, passes through the nut from one side and is not covered by the body of 40. The bore 50 is provided for receiving tie rods described later with reference to Fig. 11. Fig. 4 shows the ball screw-nut mechanism just prior to assembling the holding body. 40 on the nut 12. All the recirculation inserts 32 are in place in their housing. The holding body 40 has a segmented inner ring whose segments 46 engage in a circular groove 48, provided on the outer face 18 of the nut 12, to hold the sleeve on the nut. The holding cop 40 also has a segmented shoulder 47 which abuts on a face 13 of the nut close to the groove 48.
    [0017] Figure 10 shows on a larger scale a recirculation insert 32 of generally cylindrical shape. In particular, it is possible to observe the transfer groove 36 on the first end 34 of the insert, and the orientation tenon 38 on the opposite end. In the particular embodiment of the recirculation insert illustrated in FIG. 10, the transfer groove is extended by lugs 35. The lugs 35 are intended to protrude into the raceway of the balls so as to stop the balls. circulation and force them to leave the raceway to continue their journey in the transfer groove 36. For this purpose, the tabs each have a stop edge of the balls indicated with the reference 37. The stop edges of balls 37 and the tabs 35 are susceptible to significant stress. Also the insert 32 has in this case buttresses 39 opposite the stop edges 37. The buttresses 39 protrude radially on the cylindrical body of the recirculation insert. Also to prevent the buttresses 39 hindering the introduction of the recirculation insert in its housing, the insert is provided with a retractation recess 33. This is a longitudinal slot that opens into 3028714 19 the raceway. The width of the slot is both wide enough to allow complete radial retraction of the buttresses and sufficiently reduced so that the balls do not enter. The slot forming the retraction recess 33 separates the end of the insert into two portions which constitute bending legs. The retraction of the buttresses 39 by the bending of legs mentioned above is illustrated in FIG. 7. FIG. 7 shows, in section, a recirculation insert 32 at the moment of its insertion into its recess 30. When the recirculation insert is fully inserted, that is to say, when the shoulder formed by the orientation pin 38 abuts against the outer face 18 of the nut 12, the bending of the legs is released and the buttresses are housed in 26. The position of the recirculation insert 32 and buttresses 39 can be seen in FIG. 8. FIG. 8 shows in section a detail of the nut and the screw in the vicinity of an insert of FIG. recirculation, 15 after its establishment in his home. The buttresses occupy a significant part of the section of the raceway. However, the buttresses are dimensioned and held so as not to touch the screw 14 or the nut 12, A slight clearance is preserved so as to avoid unnecessary friction. This aspect is illustrated in FIG. 9, which is a section of the raceway passing through one of the buttresses 39. The ball screw-nut mechanism can be used for various applications. A particular application is shown in FIG. 11. This is an application to an electric pruner 60. The pruner is provided with a rotary electric motor 62, and a screw-nut mechanism 25 in accordance with invention for transforming the rotational movement of the motor into a translation movement. The motor 62 connected to the screw 14 of the screw-nut mechanism by means of a gearbox 63 so as to turn the screw 14 in a clockwise or counterclockwise direction, depending on a command exerted on a trigger 66.
    [0018] As previously described, the rotation of the screw 14 causes the nut 12 to move parallel to the axis of the screw. The direction of movement of the nut depends on the direction of rotation of the screw. A movable drive part 68, for example a rod part, is connected to the nut by means of a suitable attachment, for example pins or pivots, which engage in the mentioned fixing bore 50. with reference to FIGS. 1, 3, 4, 5 and 12. The opposite end of the moving workpiece is connected to a cam 72 of a movable blade 70. Thus, the translational movement of the nut 12 is transmitted to the cam and causes pivoting of the movable blade 70 about a pivot 74. Depending on the direction of rotation of the screw 14, the movable blade 70 is raised, or closed on a fixed blade 76. Figure 12 shows another embodiment of the recirculation inserts 32 of a ball screw nut mechanism. In the case of Figure 12, the inserts 32 have an orientation pin 38 in the form of a disc of greater diameter than the cylindrical body of the insert. Due to the greater diameter of the post 38, it always forms a shoulder for fixing the depth of the insert in its housing. Unlike the shoulder of the insert of Figure 1, the shoulder of the insert of Figure 12 does not bear against the outer face 18 of the nut 12 but at the bottom of a depression. In the illustrated example 20, the depression is a counterbore formed in the nut around each insert housing. The depression has a depth sufficient to drown the orientation pin 38, and preferably a depth adjusted to the thickness of the disc forming the tenon. When the orienting post 38 bears in the depression, the upper surface of the tenon then comes flush with the outer face 18 of the nut 12. Thus, in the embodiment illustrated in FIG. retaining member may have a bore 42 with a smooth inner face fitted to the outer face 18 of the nut 12. Its function is limited to maintaining the inserts 32 in their housings 30. The tenon can be configured with a guide relief such as described previously. However, and advantageously, the attachment of the orientation of the insert in the housing can also be achieved by a complementarity of shape between the depression and the orientation pin. The depression then forms a fingerprint 45 of the orientation tenon. Thus, when the insert is placed in its housing, the post 38 is exactly lodged in the impression 45. The precise fixing of the orientation can be done for example by means of a tenon and a polygonal shape imprint. However, in the embodiment of Fig. 12, the post and the footprint are circular in shape. The precise fixing of the orientation of the insert in the housing, is obtained by means of a decentering of the tenon relative to the axis of the insert 32, and a corresponding shift of the cavity 45 relative to at the axis of the dwelling 30.
    权利要求:
    Claims (19)
    [0001]
    REVENDICATIONS1. - Mechanism of screw and ball nut comprising a screw (14) and a nut (12) with threads, the nut cooperating with the screw (14) via balls (28) being able to circulate in a raceway ( 26) formed by the threads (22, 24) of the screw and the nut opposite, the nut being further provided with at least one insert (32) recirculation inserted from an outer face (18) of the nut, in at least one housing (30), cylindrical, passing through the nut of the outer face (18) of the nut (12) to the thread (22) of the nut, the recirculation insert ( 32) having a first end (34) with a ball transfer groove (36) facing the screw (14), characterized in that - the mechanism comprises a holding body of the recirculation insert (32), configured to maintain the recirculation insert in the housing, - the recirculation insert (32) has a second end with a bearing shoulder on a bearing surface of the nut (12), - the second end of the recirculation insert (32) comprises an orientation pin (38) having a predetermined angular position and fixed relative to the groove (36) of transfer of balls, the tenon of an orientation cooperating with one of at least one guide relief (44) of the holding body, and an impression (45) of the nut, to fix an orientation of the recirculation insert (32) in the housing, orientation of the insert being fixed so that the transfer groove (36) is fitted to the raceway.
    [0002]
    2. - Mechanism according to claim 1, wherein the orientation pin (38) forms the bearing shoulder of the recirculation insert (32). 3028714 23
    [0003]
    3. - Mechanism according to one of the preceding claims, wherein the bearing pad is one of the outer face (18) of the nut and a bearing pad in a depression formed around the housing (30). . 5
    [0004]
    4. - Mechanism according to claim 3, wherein the depression forms the cavity (45) cooperating with the tenon.
    [0005]
    5. - Mechanism according to one of the preceding claims, wherein the recirculation insert has a circular shoulder forming the orientation pin and 10 cooperating with a corresponding circular imprint formed in the nut (12) in depression relative to the outer face (18) of the nut, the circular imprint and the circular shoulder being respectively off-axis with respect to the housing of the insert and relative to the recirculation insert. 15
    [0006]
    6. - Mechanism according to one of claims 1 to 4, wherein the post has a polygonal shape, preferably square, and cooperates with a depression (45) respectively fitted on the tenon.
    [0007]
    7. - Mechanism according to claim 6 wherein the tenon is offset with respect to the recirculation insert.
    [0008]
    8. - Mechanism according to one of the preceding claims, wherein the pin has an elongate shape and wherein the cavity (45) is a groove in the nut, the groove having a width adjusted to the tenon. 25
    [0009]
    9. - Mechanism according to one of the preceding claims, wherein the holding body (40) has a bore (42) adapted to receive the nut, and wherein at least one guide relief (44) extends parallel. to an axis of the bore (42). 3028714 24
    [0010]
    10. - Mechanism according to one of the preceding claims, wherein the guide relief (44) is a depression groove.
    [0011]
    11. - Mechanism according to one of the preceding claims, comprising a plurality of inserts (32) recirculating balls housed in a corresponding plurality of housing (30) for inserts.
    [0012]
    12. - Mechanism according to one of the preceding claims, wherein the holding body (40) comprises a plurality of guide reliefs, uniform angular distribution, cooperating with a plurality of orientation pins (38) of a plurality of recirculation inserts (32).
    [0013]
    13. - Mechanism according to one of the preceding claims, wherein each guide relief (44) is adapted to receive a plurality of orientation pins 15 (38).
    [0014]
    14. - Mechanism according to one of the preceding claims, comprising a plurality of recirculation inserts, the inserts being angularly distributed around the nut and being spaced axially respectively by a distance 20 corresponding to multiples of one step of the thread (22) of the nut (12).
    [0015]
    15. - Mechanism according to one of the preceding claims, comprising a plurality of recirculation inserts (32), the inserts being angularly distributed around the nut and being spaced axially respectively by a distance 25 corresponding to a pitch of the thread. (22) of the nut (12).
    [0016]
    16. - Mechanism according to one of the preceding claims wherein the recirculation insert has at least one lug (35) formed in the vicinity of the bead transfer groove, and extending in the raceway (26). in the direction of the screw, the guide lug having an edge (37) for stopping the balls. 3028714 25
    [0017]
    17. - Mechanism according to claim 16, wherein the lug (35) has a buttress (39) opposite the stop edge (37), the buttress protruding radially on the body of the recirculation insert, and s' extending into the raceway. 5
    [0018]
    18. - Mechanism according to claim 15, wherein the recirculation insert has a recess (33) of radial retraction of the tab (35), the tab being connected to the body of the insert flexibly with a flexural amplitude in the direction of the retraction recess equal to a length of the projecting buttress (39). 10
    [0019]
    19. - portable power tool (60), selected from secateurs and shears, comprising a movable blade (70), a rotary motor (62) and a movable part (68) for driving the movable blade, driven by the motor, and a ball screw-nut mechanism (10) according to any one of the preceding claims, the nut of the screw-nut ball mechanism being connected to the movable blade drive (68) and the screw (14) being connected to the motor (62).
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    同族专利:
    公开号 | 公开日
    US20170241525A1|2017-08-24|
    JP2017538085A|2017-12-21|
    CN107002842A|2017-08-01|
    US10697527B2|2020-06-30|
    BR112017007567A2|2018-02-06|
    ES2716374T3|2019-06-12|
    JP6630362B2|2020-01-15|
    EP3224500B1|2019-01-09|
    KR20170090453A|2017-08-07|
    PL3224500T3|2019-06-28|
    TR201903306T4|2019-03-21|
    FR3028714B1|2017-03-31|
    EP3224500A1|2017-10-04|
    CN107002842B|2020-08-21|
    PT3224500T|2019-04-23|
    WO2016083692A1|2016-06-02|
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    法律状态:
    2015-11-17| PLFP| Fee payment|Year of fee payment: 2 |
    2016-05-27| PLSC| Search report ready|Effective date: 20160527 |
    2016-09-30| PLFP| Fee payment|Year of fee payment: 3 |
    2017-11-27| PLFP| Fee payment|Year of fee payment: 4 |
    2019-11-25| PLFP| Fee payment|Year of fee payment: 6 |
    2020-11-25| PLFP| Fee payment|Year of fee payment: 7 |
    优先权:
    申请号 | 申请日 | 专利标题
    FR1461401A|FR3028714B1|2014-11-25|2014-11-25|SCREW MECHANISM AND BALL NUT.|FR1461401A| FR3028714B1|2014-11-25|2014-11-25|SCREW MECHANISM AND BALL NUT.|
    KR1020177017612A| KR20170090453A|2014-11-25|2015-11-03|Ball screw and nut mechanism|
    PCT/FR2015/052961| WO2016083692A1|2014-11-25|2015-11-03|Ball screw and nut mechanism|
    PT15804875T| PT3224500T|2014-11-25|2015-11-03|Ball screw and nut mechanism|
    US15/513,273| US10697527B2|2014-11-25|2015-11-03|Ball-screw and nut mechanism|
    ES15804875T| ES2716374T3|2014-11-25|2015-11-03|Screw mechanism and ball nut|
    CN201580063514.4A| CN107002842B|2014-11-25|2015-11-03|Ball screw nut mechanism|
    TR2019/03306T| TR201903306T4|2014-11-25|2015-11-03|Ball screw and nut mechanism.|
    PL15804875T| PL3224500T3|2014-11-25|2015-11-03|Ball screw and nut mechanism|
    JP2017546044A| JP6630362B2|2014-11-25|2015-11-03|Ball screw nut mechanism|
    EP15804875.1A| EP3224500B1|2014-11-25|2015-11-03|Ball screw and nut mechanism|
    BR112017007567-9A| BR112017007567A2|2014-11-25|2015-11-03|ball screw and nut mechanism|
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