headstock structure of CNC lathe for vibration absorbing

专利摘要:
PURPOSE: A major shaft structure of CNC(computerized numerical control) lathe for vibration damping is provided to effectively absorb vibration generated upon cutting and to obtain high quality machining face by filling shock absorbing materials into the major shaft. CONSTITUTION: A CNC lathe comprises a major shaft structure with its inner portion formed with hollow shape for absorbing vibration from the major shaft. The major shaft has a bottom closed structure, and a shock absorbing material(40) is filled into the inner space of the major shaft. An opening of the inner space of the major shaft is closed with a cover(50) as to prevent the shock absorbing material from being leaked out. The shock absorbing material is selected from following group including sand, rubber, resin concrete, or silicon rubber. Around the opening is formed a sill for cover.
公开号:KR20020059104A
申请号:KR1020000087649
申请日:2000-12-31
公开日:2002-07-12
发明作者:이창호
申请人:양재신；대우종합기계 주식회사；
IPC主号:

专利说明:

Headstock structure of CNC lathe for vibration absorbing}
[16] The present invention relates to a spindle structure of a numerical control lathe for vibration suppression that can be applied to more effectively dampen vibrations in a spindle of a computerized numerical control lathe (CNC lathe). The present invention relates to a main shaft structure of a numerical control lathe for vibration suppression to increase a damping ratio by injecting a vibration absorber that absorbs vibration into an interior of a main shaft.
[17] In general, a computer numerical control lathe (hereinafter referred to as "CNC lathe") is provided with a spindle 12 in the main shaft 10, as shown in Figure 1 attached to the turret for the tool change on the bed (14) (16) is configured to process the workpiece rotated at high speed by being bitten by the spindle 12 while being positioned in the X and Y axes by the servomotor.
[18] The inner structure of the spindle shaft 10 in the conventional CNC lathe is hollow as shown in FIGS. 2 to 4, and the holes 10a and 10b are formed on the side and bottom of the spindle shaft 10. 10c is formed, the bed 14 is hardly absorbed from the workpiece due to the vibration generated by the spindle 12 and the cutting resistance during machining, and is transmitted to the bed 14 because the structure is transmitted to the bed 14. The vibration transmitted to) is transferred to the X-axis and Y-axis again, which not only lowers the precision of the feed system but also brings a vicious cycle of lowering the processing quality as it is re-transmitted to the workpiece.
[19] Particularly, when machining hard steels of H _R C60 or higher, high frequency vibration occurs due to cutting resistance. At this time, the existing main shaft structure does not absorb high frequency vibration, so there is a limit to increase the degree of machining. The chattering phenomenon occurs due to resonance during cutting, which causes a rough processing surface.
[20] SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object thereof is to provide a spindle head structure of a numerical control lathe for vibration suppression which can improve the processing accuracy by damping vibration generated during cutting. .
[21] In order to achieve the object of the present invention, the side of the main shaft has a closed structure, fills the inside of the main shaft with a dust absorbing material through a hole formed in the lower side, and closes the hole with a cover to the headstock of the numerical control shelf for vibration suppression A structure is provided.
[1] 1 is a perspective view showing the structure of a general numerical control lathe
[2] Figure 2 is a front sectional view showing the structure of a conventional headstock and bed
[3] Figure 3 is a front sectional view showing a structure of a conventional headstock
[4] Figure 4 is a bottom view showing the bottom structure of the conventional headstock
[5] 5 is a front sectional view showing a main shaft structure according to the present invention;
[6] Figure 6 is a bottom view showing the bottom structure of the headstock according to the present invention
[7] 7 is a view showing a mathematical model of the headstock structure according to the present invention;
[8] 8 is a graph showing the vibration amplification rate in the frequency range according to the damping characteristics of the structure
[9] 9 is a graph showing a time response curve due to the impact excitation of a conventional headstock
[10] 10 is a graph showing a time response curve due to the impact excitation of the headstock according to the present invention
[11] 11 is a graph comparing the vibration magnification in the frequency range of the conventional headstock and the headstock of the present invention
[12] * Explanation of Signs of Major Parts of Drawings *
[13] 30: headstock 32: hole
[14] 37: hollow portion 40: dust absorbing material
[15] 50: cover
[22] Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[23] 5 and 6, the side of the main shaft 30 has a closed structure, and is formed by injecting the absorber 40 therein through the hole 32 formed at the lower side thereof. (40) When the injection is completed, the hole 32 is closed with the cover 50, so that the dust absorber 40 is not leaked out.
[24] Here, the absorber 40 may be made of, for example, sand, rubber, resin concrete, and the cover 50 may be made of silicone rubber or the like.
[25] Then, around the hole 32 formed in the lower portion of the main shaft 30 to form a jaw (32a) that the cover 50 can be placed.
[26] Hereinafter, the operation according to the present invention will be described in detail with reference to the accompanying drawings.
[27] First, as shown in FIGS. 5 and 6, when the vibration generated in the spindle or the workpiece is transmitted to the headstock 30, the vibration is transferred to the absorber 40 filled in the headstock 30 and absorbed. Then attenuated.
[28] That is, Figure 7 shows a mathematical model of the headstock 30 structure, the mathematical model equation presented here is as follows.
[29] M "+ C ' + K = F
[30] Here, M, C, and K represent mass, damping rate, and rigidity, respectively.
[31] The above equation is expressed as Magnification Factor expressed as a function of frequency ratio.
[32]
[33] here, , , , to be.
[34] FIG. 8 is a graph showing the enlargement rate expression expressed as a function of the frequency ratio as a graph according to the damping ratio. Here, it can be seen that as the damping ratio zeta increases, the vibration magnification rate is significantly reduced. Therefore, it is theoretically proved that artificially injecting the absorber 40 into the hollow portion 37 inside the main shaft 30 to increase the damping ratio is effective for suppressing vibration.
[35] In order to confirm the validity of the present invention, the impact test was proved by the impact test of the headstock 30 injecting the existing headstock and the dust absorber 40,
[36] The equation for calculating the damping ratio through the experiment is as follows.
[37] , to be.
[38] Here, {CHI} _ {1} and {CHI} _ {2} represent the response size between time-domain data periods.
[39] 9 and 10 are graphs showing the time response curves of the conventional headstock and the headstock according to the present invention, respectively. As shown therein, vibration suppression of the headstock 30 according to the present invention is effective. It can be seen that.
[40] The attenuation ratio can be obtained from the time-domain data.
[41] In the case of the existing headstock (10) Is,
[42] The damping ratio zeta is 0.06.
[43] In the case of the present invention headstock 30 Is,
[44] The damping ratio zeta is 0.21.
[45] It can be seen that the headstock 30 of the present invention is effective for vibration suppression (damping) from the damping ratio value obtained through the experiment.
[46] 11 is a graph comparing the vibration amplification ratio in the frequency range of the conventional headstock and the headstock of the present invention. As shown in FIG. 11, the headstock 30 of the present invention has a much higher damping ratio than that of the headstock 10. You can see it.
[47] As described above, the present invention can more effectively absorb the vibration generated during cutting by filling the absorbent material in the main shaft of the CNC lathe, and in particular, processing a steel material of high hardness material that is susceptible to high frequency vibration. In this case, it is possible to prevent chattering caused by resonance and to obtain a higher quality machining surface.

权利要求:
Claims (5)
[1" claim-type="Currently amended] In the headstock structure of the numerical control lathe for vibration suppression for damping the vibration through the headstock having a hollow inside,
The main body structure of the numerical control lathe for vibration suppression, characterized in that the lower portion of the main shaft 30 to the closed structure, the interior space of the main shaft 30 is filled with the absorber (40).
[2" claim-type="Currently amended] 2. The spindle head structure of a numerical control lathe for vibration suppression according to claim 1, wherein the dust absorber (40) is sand.
[3" claim-type="Currently amended] 2. The spindle head structure of a numerical control lathe for vibration suppression according to claim 1, wherein the dust absorber (40) is rubber.
[4" claim-type="Currently amended] The headstock structure of a numerical control lathe for vibration suppression according to claim 1, wherein the dust absorber (40) is made of resin concrete.
[5" claim-type="Currently amended] The headstock structure of a numerical control shelf for vibration suppression according to claim 1, wherein the cover (50) is made of silicone rubber.

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同族专利:

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引用文献:

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公开号 | 申请日 | 公开日 | 申请人 | 专利标题

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法律状态:
2000-12-31|Application filed by 양재신, 대우종합기계 주식회사

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2000-12-31|Priority to KR1020000087649A

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2002-07-12|Publication of KR20020059104A

优先权:

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申请号 | 申请日 | 专利标题

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KR1020000087649A|KR20020059104A|2000-12-31|2000-12-31|headstock structure of CNC lathe for vibration absorbing|