Electrically-driven brush module for rotary table

Abstract

To provide an electrically-driven brush module for a rotary table.SOLUTION: An electrically-driven brush module for a rotary table is constructed so as to contain: a housing; an electrically-driven brush unit; a first holding unit; and a second holding unit. The electrically-driven brush unit comprises: an electrically-driven brush installed into the housing; an electric wire electrically connected to the electrically-driven brush; and driving force that is provided in order to deform the electrically-driven brush in a direction of an open part of a groove of the housing. The first holding unit and the second holding unit that are installed so as to be opposite to the housing resist lateral direction driving force generated by a friction between the electrically-driven brush and a turn table of the rotary table by providing first depression force and second depression force that are mutually opposite to the electrically-driven brush, largely reduce vibration, swinging, slip, line contact, or the like of the electrically-driven brush generated when the turn table is rotated at a high speed, prevent a damage on a ring side of the turn table, and hold an excellent electric contact between the electrically-driven brush and the turn table.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a rotary table for electric discharge machining, and more particularly to an electric brush module for a rotary table. [Background technology]

[0002] Electric discharge machining type rotary tables operate at high speed in liquid and are used in non-contact micro-processing equipment such as high-level discharge, line cutting, and lasers to manufacture precision elements for automotive, semiconductor, medical, and other applications.

[0003] The above-mentioned rotating table is mainly provided with a turntable and an electric brush module on a machine body, and the electric brush module is in electrical contact with the ring side of the turntable and is kept in an electrically conductive state even when the turntable rotates. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] China Utility Model Registration No. 217720205 [Patent Document 2] China Utility Model Registration No. 215870142 Summary of the Invention [Problem to be solved by the invention]

[0005] However, due to a poor design of the electric brush module, when the turntable rotates at high speed, the electric brush of the electric brush module generates large vibrations, swings, slippage, line contact, etc., which damages the ring side of the turntable and causes a defect of poor conductivity of the turntable.

[0006] In addition, in the conventional patent documents, for example, Patent Document 1 discloses a carbon brush assembly and a motor equipped with a carbon brush assembly, but the elastic damper assembly in Patent Document 1 is composed of a support spring and a damper member, and the elastic damper assembly is installed only on one side of the carbon brush box and pressed against one side of the carbon brush. Such a design with a single damper direction is prone to excessive friction between the carbon brush and the carbon brush box, which can cause the carbon brush to be damaged or the carbon brush and the carbon brush box to be stuck together. In addition, for example, Patent Document 2 discloses a vacuum cleaner motor carbon brush assembly. In Patent Document 2, due to the design of the ball bearing surrounding the electrode, etc., when the contact object moves at high speed and the electric brush tilts, the outer circumference of the bearing sleeve and the sleeve are pressed together, and the balls are pinched and locked.

[0007] Therefore, the present inventors believed that the above-mentioned drawbacks could be improved, and as a result of extensive research, they came to propose the present invention, which effectively improves the above-mentioned problems through rational design.

[0008] The present invention has been made in view of the above circumstances, and has as one example of an object thereof to solve the above problems. That is, the present invention provides an electric brush module for a rotary table. [Means for solving the problem]

[0009] In order to solve the above problem, an electric brush module for a rotary table according to one embodiment of the present invention includes a housing including an accommodating groove having a first groove wall surface, a second groove wall surface opposing the first groove wall surface, a groove bottom surface installed between the first groove wall surface and the second groove wall surface, and a groove opening surface opposing the groove bottom surface, an electric brush, an electric wire, and an elastic body, wherein the electric brush is installed in the accommodating groove and has a first side surface opposing the first groove wall surface, a second side surface opposing the second groove wall surface, an end surface opposing the groove bottom surface, and a contact surface on the opposite side to the end surface, the electric wire is inserted through the housing, the elastic body is covered by the electric wire, and the electric brush is disposed in the accommodating groove and has a first side surface opposing the first groove wall surface, a second side surface opposing the second groove wall surface, an end surface opposing the groove bottom surface, and a contact surface on the opposite side to the end surface, The electric brush unit is pressed between the bottom surface of the groove and the end surface, providing a driving force for displacing the electric brush toward the opening of the groove; a first retaining unit is installed on the housing and includes a first elastic member and a first retaining member, the first retaining member is pressed against the first side surface of the electric brush, and provides a first pressing force in a direction from the first groove wall surface to the second groove wall surface; and a second retaining unit is installed on the housing and includes a second elastic member and a second retaining member, the second retaining member is pressed against the second side surface of the electric brush, and provides a second pressing force from the second groove wall surface toward the first groove wall surface.

[0010] Preferably, the rotary table includes a machine and a turntable rotatably mounted on the machine and having a ring side, the housing is fixed to the machine, and the contact surfaces of the motorized brushes are in electrical contact with the ring side of the turntable.

[0011] Preferably, the elastic body is a compression spring, and has a first end pressed against the groove bottom surface, and a second end pressed against the end surface.

[0012] Preferably, a first position limiting groove is recessed into the first side surface of the electric brush, and the first position limiting groove is used to press the first sphere against the first side surface of the electric brush. A second position limiting groove is recessed into the second side surface of the electric brush, and the second position limiting groove is used to press the second sphere against the second side surface of the electric brush.

[0013] Preferably, the first position limiting groove has an arc-shaped cross section, the first holding member is a sphere, and the radius of the first position limiting groove is about 2% larger than the radius of the first holding member, and the second position limiting groove has an arc-shaped cross section, the second holding member is a sphere, and the radius of the second position limiting groove is about 2% larger than the radius of the second holding member.

[0014] Preferably, the first holding unit further includes a first body fixed to the housing, the first elastic member provided in the first body, and the first holding member provided in the first body and held by the first elastic member, the first holding member partially protruding into the first body. The second holding unit further includes a second body fixed to the housing, the second elastic member provided in the second body, and the second holding member provided in the second body and held by the second elastic member, the second holding member partially protruding into the second body.

[0015] Preferably, the spring constant of the elastic body is K1, the spring constant of the first elastic member and the second elastic member is K2, the compression amount of the elastic body is X1, the compression amount of the first elastic member and the second elastic member is X23, and K2 / K1=X1 / (20 * X23) conditions are met.

[0016] Preferably, the electric brush further includes a third side surface connected between the first side surface and the second side surface, an assembly groove recessed from the end surface, and a filling hole penetrating the third side surface and communicating with the assembly groove. The electric wire has a conductive portion electrically connected to the electric brush, the conductive portion of the electric wire is inserted into the assembly groove, and the filling hole, the assembly groove, and the conductive portion are filled with a conductive material.

[0017] Preferably, the assembly groove of the electric brush is a screw groove, and a brace terminal is fitted to the conductive portion of the electric wire, and the brace terminal is screwed into the assembly groove.

[0018] Preferably, the housing further includes a third groove wall surface connected between the first groove wall surface and the second groove wall surface, and a fourth groove wall surface facing the third groove wall surface. The electric brush further includes a third side surface connected between the first side surface and the second side surface and facing the third groove wall surface, and a fourth side surface on the opposite side to the third side surface. The electric brush module of the rotary table further includes a third holding unit and a fourth holding unit. The third holding unit is provided on the housing, is pressed against the third side surface of the electric brush, and includes a third holding member that provides a third pressing force from the third groove wall surface to the fourth groove wall surface. The fourth holding unit is provided on the housing, is pressed against the fourth side surface of the electric brush, and includes a fourth holding member that provides a fourth pressing force from the fourth groove wall surface to the third groove wall surface.

[0019] Preferably, a third position limiting groove is recessed into the third side surface of the electric brush, and the third position limiting groove is used to press the third sphere. A fourth position limiting groove is recessed into the fourth side surface of the electric brush, and the fourth position limiting groove is used to press the fourth sphere.

[0020] Preferably, the third position limiting groove has an arc-shaped cross section and a radius of the third position limiting groove is about 2% larger than the radius of the third holding member. The fourth position limiting groove has an arc-shaped cross section and a radius of the fourth position limiting groove is about 2% larger than the radius of the fourth holding member.

[0021] Preferably, the third holding unit further includes a third main body fixed to the housing, a third elastic member provided in the third main body, and the third holding member provided in the third main body and held by the third elastic member, and the third holding member partially protrudes into the third main body. The fourth holding unit further includes a fourth main body fixed to the housing, a fourth elastic member provided in the fourth main body, and the fourth holding member provided in the fourth main body and held by the fourth elastic member, and the fourth holding member partially protrudes into the fourth main body. Effect of the Invention

[0022] The present invention is configured as described above and therefore provides the effects described below. The first and second holding units installed to face the housing provide the electric brush with first and second pushing forces facing each other, thereby resisting a lateral thrust force generated by friction between the electric brush and the turntable of the rotary table, greatly reducing vibration, shaking, slippage, line contact, etc. of the electric brush generated when the turntable rotates at high speed, preventing damage to the ring side of the turntable, and maintaining good electrical contact between the electric brush and the turntable. In addition, the present invention has a function of the electric brush automatically returning to its original center position, preventing the problem of excessive friction generated between the electric brush and the turntable due to the electric brush being tilted, resulting in burnout of the motor of the rotary table.

[0023] Other objects, configurations and effects of the present invention will become apparent from the following detailed description of the preferred embodiments of the present invention. [Brief description of the drawings]

[0024] [Figure 1] FIG. 2 is a schematic assembly diagram showing a state in which a machine is installed on a rotary table according to the first embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view taken along line 2-2 in FIG. [Diagram 3] FIG. 2 is an oblique assembly view showing the electric brush module for a rotary table according to the first embodiment of the present invention. [Figure 4] FIG. 1 is a schematic development view showing an electric brush module for a rotary table according to a first embodiment of the present invention. [Figure 5A] FIG. 5 is a cross-sectional view taken along line 5A-5A in FIG. [Figure 5B] FIG. 5 is a cross-sectional view taken along line 5B-5B in FIG. [Figure 6A] FIG. 11 is a schematic development view showing a state in which an electric brush according to a second embodiment of the present invention is separated from a conductor. [Figure 6B] FIG. 11 is a schematic diagram showing a combination of an electric brush and a conductor according to a second embodiment of the present invention. [Figure 7] FIG. 11 is an oblique assembly view showing an electric brush module for a rotary table according to a third embodiment of the present invention. [Figure 8] FIG. 8 is a cross-sectional view taken along line 8-8 in FIG. [Figure 9] FIG. 11 is a cross-sectional view showing an electric brush module for a rotary table according to a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] Hereinafter, the embodiments of the present invention will be described in detail. However, the present invention is not limited to these, and various modifications are possible within the scope of the description. The technical scope of the present invention also includes embodiments obtained by appropriately combining the technical means disclosed in the different embodiments.

[0026] (First embodiment) First, an electric brush module for a rotary table according to the present invention will be described with reference to Figs. 1 and 2. There are two sets of electric brush modules, which are mounted on the rotary table 10, and the rotary table 10 includes a machine 11 and a turntable 12 which is rotatably mounted on the machine 11 and has a ring side 121. Hereinafter, one set of the electric brush modules will be described. With reference to Figs. 3 and 5 as well, the electric brush module is mainly configured to include a housing 20, an electric brush unit A, a first holding unit 61, and a second holding unit 62. Each of these will be described below.

[0027] <Housing 20> The housing 20 is fixed to the machine 11 and is formed by locking the first housing 20A and the second housing 20B with the screw 20C, and includes a receiving groove 21 having a first groove wall 211, a second groove wall 212 opposite to the first groove wall 211, a groove bottom 213 installed between the first groove wall 211 and the second groove wall 212, and a groove opening 214 opposite to the groove bottom 213. In this embodiment, the housing 20 further includes a first side hole 215 penetrating the first groove wall 211, a second side hole 216 penetrating the second groove wall 212, and a through hole 217 penetrating the groove bottom 213.

[0028] <Electric brush unit A> It comprises an electric brush 30, an electric wire 40, and an elastic body 50.

[0029] <The electric brush 30> The electric brush 30 is installed in the receiving groove 21 of the housing 20, but does not contact the receiving groove 21. The electric brush 30 has a first side surface 31 facing the first groove wall surface 211, a second side surface 32 facing the second groove wall surface 212, an end surface 33 facing the groove bottom surface 213, and a contact surface 34 on the opposite side of the end surface 33 and electrically contacting the ring side 121 of the turntable 12. In this embodiment, a first position limiting groove 311 extending along the length direction is recessed in the first side surface 31, and a second position limiting groove 321 extending along the length direction is recessed in the second side surface 32, and the first position limiting groove 311 and the second position limiting groove 321 have a cross section of an arc shape.

[0030] <The electric wire 40> It has an insulating portion 41 that is inserted into the through hole 217 of the housing 20 and positioned within the accommodating groove 21, and a conductive portion 42 that protrudes from the insulating portion 41 and is electrically connected to the electric brush 30.

[0031] <The Elastic Body 50> The elastic body 50 is covered by the insulating portion 41 and pressed between the groove bottom surface 213 and the end surface 33, and provides a driving force for displacing the electric brush 30 in the direction of the groove opening 214, thereby holding the contact surface 34 of the electric brush 30 in electrical contact with the ring side 121 of the turntable 12. In this embodiment, the elastic body 50 is a compression spring, and has a first end 51 pressed against the groove bottom surface 213 and a second end 52 pressed against the end surface 33.

[0032] <First holding unit 61> The electric brush 30 includes a first body 611 that is installed on the housing 20 and fixed to a first side hole 215 of the housing 20, a first elastic member 612 that is installed in the first body 611, and a first holding member 613 that is installed in the first body 611 and held by the first elastic member 612. The first holding member 613 partially protrudes from the first body 611 and is pressed against a first position limiting groove 311 of a first side surface 31 of the electric brush 30. The first holding unit 61 provides a first pressing force to the electric brush 30 in a direction from the first groove wall surface 211 to the second groove wall surface 212. The first elastic member 612 in this embodiment is a spring, but the present invention is not limited thereto, and may be other materials having elastic recovery force.

[0033] <Second holding unit 62> The electric brush 30 includes a second body 621 that is installed on the housing 20 and fixed to the second side hole 216 of the housing 20, a second elastic member 622 that is installed in the second body 621, and a second holding member 623 that is installed in the second body 621 and held by the second elastic member 622. The second holding member 623 partially protrudes from the second body 621 and is pressed against the second position limiting groove 321 of the second side 32 of the electric brush 30. The second holding unit 62 provides a second pressing force to the electric brush 30 in a direction from the second groove wall surface 212 to the first groove wall surface 211. The second elastic member 622 in this embodiment is a spring, but the present invention is not limited thereto, and may be other materials having elastic recovery force.

[0034] The above is a description of the configuration of each main member according to the first embodiment of the present invention. Next, the effects of the present invention will be described.

[0035] <1> Maintains good electrical contact between the electric brush 30 and the turntable 12. In the present invention, the first and second holding units 61 and 62 installed in the housing 20 are located on both sides of the electric brush 30, respectively, to provide the electric brush 30 with a first and a second pushing force that are opposed to each other, and resist a lateral thrust force generated by friction between the electric brush 30 and the turntable 12 of the turntable 10. In this way, vibration, shaking, slippage, line contact, etc. of the electric brush 30 generated when the turntable 12 rotates at high speed are significantly reduced, damage to the ring side 121 of the turntable 12 is prevented, and good electrical contact is maintained between the electric brush 30 and the turntable 12.

[0036] <2> The electric brush 30 has a function of automatically returning to its original center position. The first side 31 and the second side 32 of the electric brush 30 are respectively provided with a first position limiting groove 311 and a second position limiting groove 321 having an arc-shaped cross section. The first holding member 613 of the first holding unit 61 and the second holding member 623 of the second holding unit 62 abut against the first position limiting groove 311 and the second position limiting groove 321 having an arc-shaped cross section, respectively. In addition, the first holding unit 61 and the second holding unit 62 provide the electric brush 30 with a first pressing force and a second pressing force opposing each other. The first position limiting groove 311 and the first holding member 613, and the second position limiting groove 321 and the second holding member 623, which are arc-shaped, are combined to limit each other, so that the electric brush 30 has the function of automatically returning to its original center position. This prevents a problem that an excessive frictional force is generated between the electric brush 30 and the turntable 12 due to the tilting of the electric brush 30 and the motor (not shown) of the turntable 10 is burned out. This further prevents problems such as vibration, tilt, and sticking between the housing 20, the first holding unit 61, the second holding unit 62, and the electric brush 30, effectively reduces the friction force between the electric brush 30 and the turntable 12, reduces the driving current of the turntable 10, and achieves power saving effects.

[0037] Incidentally, the first position limiting groove 311 of the electric brush 30 is designed to have an arc-shaped cross section, and the radius of the first position limiting groove 311 is about 2% larger than the radius of the first holding member 613. The second position limiting groove 321 of the electric brush 30 is designed to have an arc-shaped cross section, and the radius of the second position limiting groove 321 is about 2% larger than the radius of the second holding member 623. In this way, the electric brush 30 has the function of automatically returning to its original center position.

[0038] In addition, the spring constant of the elastic body 50 is K1, the spring constant of the first elastic member 612 and the second elastic member 622 is K2, the compression amount of the elastic body 50 is X1, the compression amount of the first elastic member 612 and the second elastic member 622 is X23, and K2 / K1=X1 / (20 * By satisfying the above-mentioned conditional formula, the left and right vibration amplitude of the electric brush 30 that occurs when the turntable 12 rotates at high speed is limited, and the situation in which the vibration amplitude of the electric brush 30 is too large and causes the electric brush 30 to collide with the accommodation groove 21 of the housing 20 is prevented.

[0039] (Second Example) The electric brush module for a rotary table according to the second embodiment of the present invention (see Figs. 6A and 6B) differs from the first embodiment in that the electric brush 30 further includes a third side surface 35 connected between the first side surface 31 and the second side surface 32, an assembly groove 36 recessed from the end surface 33, and a filling hole 37 penetrating the third side surface 35 and communicating with the assembly groove 36, and the conductive portion 42 of the electric wire 40 is inserted into the assembly groove 36, and the filling hole 37, the assembly groove 36, and the conductive portion 42 are filled with a conductive material 100 such as tin, but the present invention is not limited thereto. In this embodiment, the assembly groove 36 of the electric brush 30 is a screw groove, and the conductive portion 42 of the electric wire 40 is covered with a brace terminal 43, which is screwed into the assembly groove 36.

[0040] In this way, when the electric wire 40 and the electric brush 30 are assembled together, the conductive material 100 is first welded to the outside of the brace terminal 43, and then inserted or screwed into the assembly groove 36 of the electric brush 30. The conductive material 100 is then heated to a molten state, poured into the assembly groove 36 through the filling hole 37 of the electric brush 30, and melted with the conductive material 100 in the brace terminal 43 of the electric wire 40, and then cooled to be integrally bonded, thus completing the electrical connection between the electric wire 40 and the electric brush 30 and increasing the tensile strength. When the electric brush 30 is replaced, the conductive material 100 in the filling hole 37 of the electric brush 30 is heated by a heating tool, the conductive material 100 is melted, and then the electric wire 40 and the electric brush 30 are rotated to separate them from each other, and the electric brush 30 is replaced. In this way, the electric wire 40 is recycled, and an environmental protection effect is achieved.

[0041] (Third Example) The electric brush module for a rotary table according to the third embodiment of the present invention (see Figures 7 and 8) differs from the first embodiment in that the housing 20 further has a third groove wall surface 218 connected between the first groove wall surface 211 and the second groove wall surface 212, and a fourth groove wall surface 219 opposite the third groove wall surface 218.

[0042] The electric brush 30 further includes a third side surface 35 connected between the first side surface 31 and the second side surface 32 and facing the third groove wall surface 218, and a fourth side surface 38 on the opposite side of the third side surface 35. In this embodiment, a third position limiting groove 351 is recessed into the third side surface 35, and a fourth position limiting groove 381 is recessed into the fourth side surface 38.

[0043] The electric brush module of the rotary table 10 further includes a third holding unit 63 and a fourth holding unit 64 .

[0044] The third holding unit 63 is installed in the housing 20 and includes a third main body 631 fixed to the housing 20, a third elastic member 632 disposed in the third main body 631, and a third holding member 633 disposed in the third main body 631 and held by the third elastic member 632. The third holding member 633 partially protrudes into the third main body 631 and is pressed against a third position limiting groove 351 of a third side surface 35 of the electric brush 30, and the third holding unit 63 provides a third pressing force to the electric brush 30 in a direction from the third groove wall surface 218 to the fourth groove wall surface 219. The third elastic member 632 according to this embodiment is a spring, but the present invention is not limited thereto, and may be another material having elastic recovery force.

[0045] The fourth holding unit 64 is installed in the housing 20 and includes a fourth main body 641 fixed to the housing 20, a fourth elastic member 642 disposed in the fourth main body 641, and a fourth holding member 643 disposed in the fourth main body 641 and held by the fourth elastic member 642. The fourth holding member 643 partially protrudes from the fourth main body 641 and is pressed against a fourth position limiting groove 381 of a fourth side surface 38 of the electric brush 30, and the fourth holding unit 64 provides a fourth pressing force to the electric brush 30 in a direction from the fourth groove wall surface 219 to the third groove wall surface 218. The fourth elastic member 642 according to this embodiment is a spring, but the present invention is not limited thereto, and may be another material having elastic recovery force.

[0046] As a result, by combining the third holding unit 63 and the fourth holding unit 64 with the first holding unit 61 and the second holding unit 62, the electric brush 30 is held by pressure in all directions, further enhancing the effect of automatically aligning the electric brush 30 to the center, and further significantly reducing problems such as vibration, shaking, slippage, line contact, tilt, and sticking of the electric brush 30 that occur when the turntable 12 rotates at high speed.

[0047] (Fourth Example) The electric brush module for a rotary table according to the fourth embodiment of the present invention (see Figure 9) differs from the first embodiment in that the first holding member 613 of the first holding unit 61 has a first cylinder 6131 located within the first main body 611 and held by the first elastic member 612, and a first arc portion 6132 connected to the first cylinder 6131, and the surface of the first arc portion 6132 is arc-shaped and is pressed against the first position limiting groove 311 on the first side 31 of the electric brush 30. The second holding member 623 of the second holding unit 62 has a second cylinder 6231 that is located in the second main body 621 and is held by the second elastic member 622, and a second arc portion 6232 that is connected to the second cylinder 6231, and the surface of the second arc portion 6232 has an arc shape and is pressed against the second position limiting groove 321 of the second side surface 32 of the electric brush 30. In this manner, another embodiment state is configured.

[0048] The above description is for the purpose of explaining the present invention, and should not be interpreted as limiting the invention described in the claims or restricting the scope of the invention. Furthermore, the configuration of each part of the present invention is not limited to the above embodiment, and various modifications are possible within the technical scope described in the claims. [Explanation of symbols]

[0049] 20. Housing 20A 1st housing 20B Second housing 20C Screw 21 Storage Groove 211 First ditch wall 212 Second groove wall 213 Groove bottom surface 214 Groove opening 215 1st side hole 216 2nd side hole 217 Through hole 218 Third Ditch Wall 219 4th Ditch Wall A Electric brush unit 30 Electric Brush 31 First aspect 311 First position limiting groove 32 Second aspect 321 Second position limiting groove 33 End face 34 Contact surface 35 Third aspect 351 3rd position limiting groove 36 Assembly groove 37 Filling Hole 38 Fourth aspect 381 4th position limiting groove 40 Electric wire 41 Insulation part 42 Conductive parts 43 Brace terminal 50 Elastic Body 51 First end 52 Second end 61 First holding unit 611 First Body 612 First elastic member 613 First retaining member 6131 1st column 6132 First arc section 62 Second holding unit 621 Second Body 622 Second elastic member 623 Second retaining member 6231 Second pillar 6232 Second arc section 63 Third Holding Unit 631 Third Body 632 Third elastic member 633 Third retaining member 64 4th Holding Unit 641 4th Body 642 Fourth elastic member 643 Fourth retaining member 100 Conductive Materials

Claims

1. a housing including a receiving groove having a first groove wall surface, a second groove wall surface opposing the first groove wall surface, a groove bottom surface disposed between the first groove wall surface and the second groove wall surface, and a groove opening surface opposing the groove bottom surface; an electric brush unit including an electric brush, an electric wire, and an elastic body, the electric brush being installed in the receiving groove and having a first side surface facing the first groove wall surface, a second side surface facing the second groove wall surface, an end surface facing the groove bottom surface, and a contact surface on the opposite side to the end surface, the electric wire being inserted through the housing, and the elastic body being covered by the electric wire and pressed between the groove bottom surface and the end surface, providing a driving force for displacing the electric brush toward an opening of the groove; a first holding unit installed in the housing, the first holding unit including a first elastic member and a first holding member, the first holding member being pressed against the first side surface of the electric brush and providing a first pressing force in a direction from the first groove wall surface to the second groove wall surface; an electric brush module for a rotary table, characterized in that it comprises a second retaining unit installed in the housing and including a second elastic member and a second retaining member, the second retaining member being pressed against the second side of the electric brush and providing a second pressing force from the second groove wall surface toward the first groove wall surface.

2. An electric brush module for a rotary table as described in claim 1, characterized in that a first position limiting groove is recessed into the first side surface of the electric brush, the first position limiting groove being used to press the first retaining member, and a second position limiting groove is recessed into the second side surface of the electric brush, the second position limiting groove being used to press the second retaining member.

3. The electric brush module for a rotary table as described in claim 2, characterized in that the cross section of the first position limiting groove is arc-shaped, the first retaining member is a sphere, and the radius of the first position limiting groove is approximately 2% larger than the radius of the first retaining member, and the cross section of the second position limiting groove is arc-shaped, the second retaining member is a sphere, and the radius of the second position limiting groove is approximately 2% larger than the radius of the second retaining member.

4. The electric brush module for a rotary table as described in claim 1, characterized in that the first retaining unit further has a first main body fixed to the housing, the first elastic member provided in the first main body, and the first retaining member provided in the first body and held by the first elastic member, the first retaining member partially protruding into the first main body, and the second retaining unit further has a second main body fixed to the housing, the second elastic member provided in the second main body, and the second retaining member provided in the second body and held by the second elastic member, the second retaining member partially protruding into the second body.

5. The spring constant of the elastic body is K1, the spring constant of the first elastic member and the second elastic member is K2, the compression amount of the elastic body is X1, the compression amount of the first elastic member and the second elastic member is X23, and K2 / K1=X1 / (20 ＊ 5. The electric brush module for a rotary table according to claim 4, characterized in that it satisfies the conditions of I.

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