• 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:
    In order to provide a controlled degradation mode of operation during a transition from autonomous steering mode to driver controlled steering mode in an emergency situation, a steering system includes a steering shaft, a movable brake mechanism between a disengaged position and a position engaged to angularly lock the steering shaft, and a neutralization device such that an external non-destructive torque applied to the steering shaft above a given threshold when the mechanism when the brake is in the engaged position causes rotation of the steering shaft.
    公开号:FR3016152A1
    申请号:FR1462562
    申请日:2014-12-17
    公开日:2015-07-10
    发明作者:Olivier Bernard Perichon；Pritish S Khale；Michael Mcfarland
    申请人:ZF Systemes de Direction Nacam SAS；
    IPC主号:
    专利说明:

    [0001] FIELD OF THE INVENTION The present invention relates to a steering system that provides a controlled degradation mode of operation during a transition between an autonomous steering mode and a steering mode. controlled by the driver, especially in emergency situations. STATE OF THE ART [0002] In order to deal with the question of an intentional and intuitive voluntary transition from an autonomous steering mode to a manual steering, it has been suggested in document US 2013 002416 to provide a vehicle steering system with a movable autonomous steering wheel from a first position to a second position and an autonomous driving electronic control unit configured to receive a signal indicating that the autonomous interface flywheel has been moved from the first position to the second position and to initialize a change in vehicle operation between the manual steering mode and the autonomous steering mode in response to receiving the signal. However, this system does not address the issue of a safe transition from the autonomous steering mode to the driver-controlled steering mode or manual initiated by the autonomous driving electronic control unit, for example in emergency situation. In a somewhat different context, the document US 6,580,989 discloses a so-called hybrid steering system that can selectively operate in one of three modes: electric steering, electronic power steering (EPAS) and manual steering. The electrical steering system includes a conductive interface system (DIS), a road contact wheel actuator (RWAS) system, and a controller for monitoring and implementing a preferred control strategy. The steering system normally operates in electric steering mode. Alternatively, operation in the EPAS mode and in the manual mode is determined by a controller in response to a malfunction in any part of the DIS or RWAS. In the EPAS mode and the manual mode, the controller causes a clutch mechanism to engage, thereby creating a mechanical connection between the airship and the rack system. In EPAS mode, either the wheel actuator in contact with the road or the reaction torque generator is available to assist the steering operation. Alternatively, in manual mode, both the DIS and the RWAS are deactivated and the vehicle can be directed by fully mechanical means. Since the driver must hold the steering wheel in all three modes of operation, no particular measure must be taken at the time of transition between the different steering modes. [0004] Accordingly, there is a need for means to ensure a safe transition from autonomous steering to a driver-controlled direction in a vehicle when the driver is unaware of the imminence of this transition. SUMMARY OF THE INVENTION [0005] According to one aspect of the invention, there is provided a steering system comprising a steering shaft and a braking mechanism movable between a disengaged position and a position engaged to angularly lock the shaft. direction, wherein the braking mechanism comprises a disabling device so that an external non-destructive torque applied to the steering shaft above a given threshold when the braking mechanism is in the engaged position causes a rotation of the steering shaft. During a transition from an autonomous steering mode to a driver controlled steering mode, the brake mechanism can be moved to the engaged position to angularly lock the steering shaft mechanically connected to the ground engaging wheels while the driver regains control of the steering wheel. Once the hands of the driver on the steering wheel, the vehicle can be directed by applying to the steering wheel a torque above the threshold of the neutralization device. According to a preferred embodiment, the neutralization device comprises a first friction element and a second friction element frictionally engaged with each other in the engaged position. The torque threshold for neutralizing the braking mechanism is given by the pressure between the first and second friction members. According to one embodiment, the first friction element is non-rotating relative to the steering shaft, at least in the engaged position. The second friction element is non-rotatable relative to the braking mechanism in the engaged position. The second friction element may be rotatable relative to the brake mechanism in the disengaged and stopped position with respect to the brake mechanism (and thus to a vehicle dashboard) to engage the brake. According to a preferred embodiment, a return mechanism is provided to engage the first and the second friction element with each other. The return mechanism preferably comprises at least one return spring for applying a predetermined restoring force to at least one of the first and second friction members.
    [0002] The predetermined return force is preferably such that the first and second friction elements begin to slip following the application of a torque at least equal to the torque threshold. The torque threshold is preferably greater than 1 Nm and less than 13 Nm. An adjustable stop fixed in an adjustable position relative to the steering shaft may be provided for charging the return spring. A particularly compact mechanism can be obtained if the return spring is a helical spring wound on the steering shaft. As will be easily understood, the system can be adjusted in various ways before being installed in the vehicle to define a desired torque threshold for the neutralization device: one can modify the material of the friction elements. If a return spring is provided, the stiffness of the spring can be changed. The easiest way to adjust the torque threshold without changing any of the steering system parts, however, is to change the location of the adjustable stop. According to one embodiment, the braking mechanism comprises a first braking element, a second braking element and an actuator, for engaging the first and second braking elements with each other in the position of the braking element. 'stop. The actuator is preferably an electromechanical actuator. According to one embodiment, at least one of the first and second braking elements comprises an annular interface in contact with the other of the first and second braking elements in the engaged position. According to one aspect of the invention, the first and second braking elements are positively engaged with each other in the engaged position. In particular, at least one of the first and second braking members may comprise an annular interface with a number of projections and / or recesses distributed over a circumference of the annular interface. According to another aspect of the invention, the first and second braking elements are in frictional engagement with each other in the engaged position. According to one embodiment, the neutralization device comprises a friction clutch comprising a first non-rotating friction element relative to the steering shaft and a second non-rotating friction element with respect to an annular interface of FIG. an annular braking element of the braking mechanism. The steering system may further include a bearing between the annular braking member and the steering shaft. According to another aspect of the invention, there is provided a steering system comprising a steering shaft, a brake mechanism movable between a disengaged position and a position engaged to angularly lock the steering shaft in a plurality of positions. stop, and a neutralization device to allow a rotation of the steering shaft following the application of an external non-destructive torque to the steering shaft above a given threshold when the brake mechanism is in the engaged position. According to another aspect of the invention there is provided a method of controlling a vehicle steering system during a transition from an autonomous operating mode to a manual mode, in which a steering shaft is stopped. in an effective position at the end of the autonomous operation mode and until a driver manually applies a torque above a given threshold to the steering wheel. DESCRIPTION OF THE FIGURES [0016] Other advantages and characteristics of the invention will emerge more clearly from the following description of specific embodiments of the invention, provided by way of non-limiting examples only, and represented in the accompanying drawings. where: - Figure 1 illustrates a steering system according to one embodiment of the invention; FIG. 2 is an isometric view of a steering column of the steering system of FIG. 1; FIG. 3 is an exploded view of a portion of the steering system of FIGS. 1 and 2, showing the assembly of a braking system on the steering column; FIG. 4 is a more detailed exploded view of the braking system of FIG. 3; - Figure 5 is a section of a steering shaft and the braking system of Figure 3; - Figure 6 is a section of an alternative embodiment of the braking system; - Figure 7 illustrates an alternative embodiment of the steering system. Corresponding reference numbers refer to identical or corresponding parts in each of the figures.
    [0003] DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS [0018] Referring to FIG. 1, a vehicle is provided with a steering system comprising a steering wheel, a steering shaft, a driving pinion which rotates with the steering wheel. steering shaft 14 and meshes with a rack 18 to move steering rods 20 connected to steering wheels in contact with the ground 22. The steering wheel 12 is connected to the steering shaft by a mechanical clutch mechanism 26 or electric. A steering motor 28 is connected to the steering shaft and controlled by a steering control unit 30. Rotation and / or torque sensors 32, 34 are provided on the steering wheel 12 and the steering shaft 14 and connected to the control unit 30. As a result, this steering system 10 is known from US 2013 002416. [0019] The steering system 10 is further provided with a friction brake mechanism 36 , which is illustrated in detail in FIGS. 2 to 5. The braking mechanism 36 comprises an actuator 38 received in an actuator housing 40 tightened with a C-shaped flange 42 on a protective tube 44 in which is mounted 14 to rotate about a steering axis 100. The actuator 38, which may be of any suitable construction, moves a notched lock 46 forward and backward against a toothed bushing 48 in a radial direction relative to to the steering axis 100. A needle bearing 50 is provided to guide the toothed sleeve 48 in rotation about the steering axis 100. The toothed bushing 48 is shrunk on an outer race of the needle bearing. The bushing has a first annular flat face 52 in frictional contact with a flat abutment ring 54 shrunk on the steering shaft 14, and a second annular face 56 opposite to the first annular face 52. A compression spring 58 is loaded between the second annular face 56 and an adjustable support washer 60 which is connected to the steering shaft 14 by shrinking at the right distance from the stop ring 54 to obtain a desired axial force through the compression spring 58 at the interface between the toothed ring 48 and the stop ring 54. As will be understood by those skilled in the art, the braking mechanism does not give any axial thrust to the steering shaft since both the adjustable bearing washer and the stop ring rest on the steering shaft. A switch 62 may be provided to allow the driver to switch between a steering mode controlled by the driver and an autonomous steering mode. This switch 62 may be on the dashboard or be integrated with the steering wheel 12, for example as disclosed in US 2013 002416. In the driver-controlled steering mode and in the autonomous steering mode, the braking mechanism is disengaged, ie the notched latch 46 is disengaged from the toothed bush 48 which is rotatable with the stop ring 54, the compression spring 58, the adjustable support washer 60 and the steering shaft 14 as an assembly. In the steering mode controlled by the driver, the clutch 26 is engaged and the steering wheel 12 is mechanically connected to the steering shaft 14 and the wheels in contact with the ground 22. The motor 28 can be used or not as an assistance device to supplement the torque provided by the driver at the steering wheel 12. In the autonomous steering mode, the clutch 26 is disengaged and the motor 28 applies a driving torque to the steering wheel. Steering shaft 14 regardless of the position of the steering wheel 12. In the autonomous steering mode, the driver can resume at least partial steering control by turning the steering wheel 12 by a predetermined angle which is detected by the sensor 32. haptic feedback (eg a click) may be provided to inform the driver that his request to resume partial or total control of the steering system 10 has been recorded and executed. Various transition strategies may be configured in response to driver input and various other vehicle parameters: the clutch 26 may remain disengaged or not, and if it is not, the motor 28 may be used or not as an assisted steering device. If also the autonomous steering mode must be interrupted urgently at the initiative of the steering control unit 30, for example due to a malfunction of the motor 28 or a sensor, before the driver has had time to regain control of the steering, the autonomous steering control unit generates an alarm to inform the driver and engages at the same time the clutch 26 and the brake mechanism 36 again. notched latch 46 engages the toothed bushing 48 to prevent rotation thereof. The toothed sleeve 48 is biased by the compression spring 58 frictionally engaged with the flat stop ring 54 and prevents rotation of the steering shaft 14. Therefore, the rack transmission 18, 16, the rods direction 20 and the wheels in contact with the ground 22 remain in the adopted position at the beginning of the transition, to allow the driver time to regain control of the steering wheel 12. As soon as the driver gives a torque to the steering wheel 12, the sensor 32 detects the applied torque and the control unit releases the notched lock 46 to release the steering shaft 14. However, if the notched lock 46 were to remain engaged, for example due to a malfunction of the sensor 32, the 38 or the control unit 30, the driver can neutralize the braking mechanism 36 by applying a torque that is greater than the nominal friction torque resulting from the axial force of the compression spring 58 on the bushing 48 to maneuver the vehicle to a total stop in a controlled degradation mode. During this maneuver, the braking mechanism 36 remains engaged, which means that the driver must continually overcome the nominal friction torque of the braking mechanism. Therefore, the nominal friction torque of the brake mechanism should preferably be both of sufficient magnitude to prevent rotation of the steering shaft before the driver has grasped the steering wheel and low enough to allow the driver to turn the steering wheel. In the embodiment illustrated in Figure 6, the braking mechanism 36 is installed on a sleeve 70 to create an independent module. The bushing 70 can be shrunk or welded on the steering shaft 14. In the embodiment of FIG. 7, the braking mechanism 36 is inserted into a steering system 10 without a clutch, comprising a steering wheel 12, a steering shaft 14, a driving gear 16 which rotates with the steering shaft 14 and meshes with a rack 18 to move steering rods 20 connected to the steering wheels in contact with the ground 22. A motor direction 28 is connected to the steering shaft and controlled by a steering control unit 30. The steering wheel 12 is connected to a feedback motor 80. Rotation and / or torque sensors 32, 34 are provided on the steering wheel. 12 and on the steering shaft 14 and connected to the control unit 30. Various other modifications are envisaged. Depending on the available installation space, the compression spring 58 can be replaced by a Belleville washer. The bearing 50 for guiding the bushing can be of any type, for example a ball bearing with or without a cage or a plain bearing to obtain a reduction in weight or to meet space constraints. An adjustment can be obtained by a correct selection of the materials and the surface roughness or coefficient of friction at the friction interface between the flat abutment ring 54 and the toothed sleeve 48. In particular, use plastic, rubber, ceramic and / or organic resin as well as steel. The support ring and / or the adjustable stop ring (s) can be replaced by nuts if the shaft is provided for external threading. This allows a very precise adjustment of the slip torque.
    权利要求:
    Claims (21)
    [0001]
    A steering system, comprising a steering shaft and a braking mechanism movable between a disengaged position and a position engaged to angularly lock the steering shaft, wherein the braking mechanism comprises a disabling device so that an external non-destructive torque applied to the steering shaft above a given torque threshold when the brake mechanism is in the engaged position causes rotation of the steering shaft.
    [0002]
    The steering system of claim 1, wherein the braking mechanism comprises a first friction member and a second friction member frictionally engaged with each other in the engaged position.
    [0003]
    3- steering system according to claim 2, wherein the first friction element is non-rotatable relative to the steering shaft in the engaged position.
    [0004]
    4- A steering system according to claim 3, wherein the second friction element is non-rotatable relative to the braking mechanism in the engaged position.
    [0005]
    The steering system of claim 4, wherein the second friction element is rotatable relative to the brake mechanism in the disengaged position.
    [0006]
    The steering system of claim 4, further comprising a biasing mechanism for frictionally engaging the first friction member and the second friction member.
    [0007]
    The steering system of claim 6, wherein the biasing mechanism comprises at least one return spring for applying a predetermined restoring force to at least one of the first and second friction members.
    [0008]
    8- A steering system according to claim 7, wherein the predetermined return force is such that the first and second friction elements begin to slip following the application of a torque greater than the torque threshold.
    [0009]
    The steering system of claim 7, further comprising an adjustable stop for loading the return spring, the adjustable stopper being fixed in an adjustable position relative to the steering shaft. 10
    [0010]
    10-steering system according to claim 7, wherein the return spring is a coil spring wound around the steering shaft.
    [0011]
    The steering system of claim 1, wherein the torque threshold is greater than 1 Nm and less than 13 Nm.
    [0012]
    The steering system of claim 1, wherein the braking mechanism comprises a first braking member, a second braking member, and an actuator engaging the first and second braking members with each other in the position engaged. 20
    [0013]
    The steering system of claim 12, wherein the actuator is an electromechanical actuator.
    [0014]
    The steering system of claim 12, wherein at least one of the first and second braking members comprises an annular interface in contact with each other of the first and second braking members in the engaged position.
    [0015]
    The steering system of claim 12, wherein the first and second braking members are positively engaged with each other in the engaged position.
    [0016]
    The steering system of claim 15, wherein at least one of the first and second braking members comprises an annular interface with a number of projections and / or recesses distributed over a circumference of the annular interface.
    [0017]
    17-steering system according to claim 12, wherein the first and second braking elements are engaged with each other by friction in the engaged position.
    [0018]
    The steering system according to claim 1, wherein the neutralization device comprises a first non-rotating friction element relative to the steering shaft and a second non-rotating friction element relative to an annular interface of an element. annular braking of the braking mechanism.
    [0019]
    The steering system of claim 18, further comprising a bearing between the annular braking member and the steering shaft.
    [0020]
    A steering system, comprising a steering shaft, a braking mechanism movable between a disengaged position and a position engaged to angularly lock the steering shaft in a plurality of stopping positions, and a disabling device to enable rotation of the steering shaft. the steering shaft following the application of an external non-destructive torque to the steering shaft above a given threshold when the brake mechanism is in the engaged position.
    [0021]
    21-A method of assembling a steering system, comprising the steps of: assembling a braking mechanism on a steering column so as to be movable between a disengaged position and a position engaged to stop the angle of a steering shaft, wherein the braking mechanism comprises a neutralization device, and adjusting the neutralization device such that an external non-destructive torque applied to the steering shaft above a given torque threshold when the braking mechanism is in the engaged position causes a rotation of the steering shaft.
    类似技术:
    公开号 | 公开日 | 专利标题
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    同族专利:
    公开号 | 公开日
    US9669864B2|2017-06-06|
    DE102014226154A1|2015-07-23|
    FR3016152B1|2019-05-31|
    US20150191198A1|2015-07-09|
    引用文献:
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    US11105330B2|2018-08-29|2021-08-31|Borgwarner Inc.|Power transmitting component having a shaft with a circumferential channel communicating fluid between a shaft-driven pump and a feed conduit formed in the shaft|
    DE102019102069A1|2019-01-28|2020-07-30|Bayerische Motoren Werke Aktiengesellschaft|Switchable clutch for a steer-by-wire steering system, steer-by-wire steering system, method for operation and vehicle|
    法律状态:
    2015-12-21| PLFP| Fee payment|Year of fee payment: 2 |
    2016-12-31| PLFP| Fee payment|Year of fee payment: 3 |
    2017-12-26| PLFP| Fee payment|Year of fee payment: 4 |
    2018-01-05| PLSC| Publication of the preliminary search report|Effective date: 20180105 |
    2019-12-27| PLFP| Fee payment|Year of fee payment: 6 |
    2020-12-22| PLFP| Fee payment|Year of fee payment: 7 |
    2021-12-15| PLFP| Fee payment|Year of fee payment: 8 |
    优先权:
    申请号 | 申请日 | 专利标题
    US14/149,309|US9669864B2|2014-01-07|2014-01-07|Friction brake mechanism and associated steering column|
    US14149309|2014-01-07|
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