JP6943126B2 - Actuator - Google Patents

Description

The present invention relates to actuators.

As a clamp mechanism that can be used for an actuator , for example, the clamp mechanism described in Patent Document 1 is known. The clamp mechanism described in Patent Document 1 includes a shaft member, a brake piston and a stepping piston inserted into the shaft member, a countersunk spring-like member arranged between the brake piston and the stepping piston, and a brake piston. It has an urging means for urging the brake piston in the forward direction and a first pressure chamber for urging the brake piston in the opposite direction. In this configuration, the shaft member is clamped by narrowing the disc spring-like member by the urging means. Further, the shaft member is unclamped by inputting the fluid pressure into the first pressure chamber.

Japanese Unexamined Patent Publication No. 9-174358

In the clamp mechanism of Patent Document 1, a brake piston and a disc spring-like member are arranged side by side in the axial direction of the shaft member. Therefore, in the clamp mechanism of Patent Document 1, it is difficult to reduce the axial dimension of the shaft member.

The present invention has been made in view of the above, and an object thereof is to provide a capable actuators to reduce the dimension in the axial direction.

The actuator of this embodiment is a cylinder having a shaft member, a collet through which the shaft member penetrates, a piston through which the shaft member penetrates, a cylinder tube accommodating the piston, and an elastic member for urging the piston. When, wherein the piston is in contact with the outer peripheral surface of said collet by said elastic member, and a clamping mechanism which have a chuck portion pressing said collet to said shaft member, can move the shaft member in the axial direction The clamp mechanism is provided with a drive unit capable of rotating the shaft member, and the chuck portion is moved by the piston moving along the shaft member in the direction in which the elastic member is urged. The piston is in contact with the outer peripheral surface of the collet so as to press the collet against the shaft member, and when gas or liquid is supplied to the inside of the cylinder tube, the piston resists the urging by the elastic member. By moving along the shaft member, the chuck portion releases the pressing of the collet against the shaft member, so that the collet is separated from the shaft member.

According to this configuration, the elastic member can be urged so that the chuck portion is in contact with the outer peripheral surface of the collet. Then, the chuck portion can press the collet against the shaft member to clamp the shaft member. Further, since the chuck portion is configured to be in contact with the outer peripheral surface of the collet, it overlaps with the outer peripheral surface in the radial direction. With such a configuration, the axial dimension of the clamp mechanism can be reduced. Further, the shaft member can be unclamped by supplying gas or liquid to the inside of the cylinder tube. Further, according to this configuration, the axial dimension of the actuator can be reduced.

As a preferred embodiment, the outer peripheral surface is a tapered surface whose diameter decreases as it approaches the chuck portion, and the chuck portion is an inclined surface facing the outer peripheral surface.

According to this configuration, the inclined surface can come into surface contact with the tapered surface when no gas or liquid is supplied to the inside of the cylinder tube. As a result, the frictional force generated between the collet and the chuck portion can be increased as compared with the case where the outer peripheral surface of the collet and the chuck portion are in line contact or point contact. Therefore, when the collet clamps the shaft member, it is possible to prevent the outer peripheral surface of the collet from slipping and the chuck portion.

As a preferred embodiment, the clamp mechanism and the housing for accommodating the drive unit are provided, and the drive unit is arranged with a first rotor rotatable with respect to the housing and a radial outer side of the first rotor, and the housing. It has a second rotor that is rotatable with respect to a second rotor, a nut, and a spline outer cylinder, and the shaft member is arranged so as to penetrate the first rotor and is arranged in one of the axial directions from the first rotor. The protruding first portion has a threaded portion, the second portion protruding from the first rotor to the other in the axial direction has a groove portion along the axial direction, and the nut is screwed into the threaded portion. Then, the shaft member is rotated together with the first rotor to move the shaft member in the axial direction, and the spline outer cylinder guides the shaft member in the axial direction along the groove portion and rotates together with the second rotor. Then, the shaft member is rotated in the axial direction of the rotation shaft of the second rotor.

According to this configuration, since the nut and the spline outer cylinder are arranged outside the axial direction of the rotating shaft with respect to the first rotor, the first rotor and the second rotor can be miniaturized in the radial direction. As a result, the footprint of the actuator can be reduced.

According to the present invention, it is possible to provide actuators capable of reducing the dimension in the axial direction.

FIG. 1 is a partial cross-sectional view of the actuator of the present embodiment. FIG. 2 is a cross-sectional view of a main part showing the main part in FIG. FIG. 3 is a cross-sectional view of a two-axis integrated motor having a plane orthogonal to the rotation axis. FIG. 4 is a cross-sectional view of a main part showing the main part in FIG. FIG. 5 is a cross-sectional view of a main part showing the main part in FIG. FIG. 6 is a cross-sectional view of a main part showing a clamping mechanism in an unclamped state. FIG. 7 is a diagram showing a state in which the screw shaft is raised from the state shown in FIG. FIG. 8 is a flowchart showing an example of the operation procedure of the actuator of the present embodiment.

An embodiment (embodiment) for carrying out the invention will be described in detail with reference to the drawings. The present invention is not limited to the contents described in the following embodiments. In addition, the components described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Furthermore, the components described below can be combined as appropriate.

FIG. 1 is a partial cross-sectional view of the actuator of the present embodiment. The cross section of FIG. 1 is a cross section taken along a plane including the rotation axis AX, but the internal configuration of the nut 51, which will be described later, is omitted. In the cross section of FIG. 1, in order to show the position of the fixing member, a partial cross section is shown so that another cross section can be seen as appropriate. FIG. 2 is a cross-sectional view of a main part (two-axis integrated motor MP) shown in FIG. FIG. 3 is a cross-sectional view of a two-axis integrated motor MP having a plane orthogonal to the rotation axis AX. FIG. 4 is a cross-sectional view of a main part showing a main part (housing for a spline outer cylinder described later) in FIG. FIG. 5 is a cross-sectional view of a main part showing the main part (clamp mechanism described later) in FIG. FIG. 6 is a cross-sectional view of a main part showing a clamping mechanism in an unclamped state. FIG. 7 is a diagram showing a state in which the screw shaft is raised.

The actuator 1 shown in FIG. 1 is used as, for example, a pick-and-place device. The actuator 1 includes an arm portion 80 for transferring a work, a biaxial integrated motor (driving unit) MP for driving the arm portion 80, a ball screw 50 and a ball spline 60 connected to the biaxial integrated motor MP, and a clamp. It has a mechanism 130 and. Hereinafter, the direction parallel to the Z axis, the direction from the two-axis integrated motor MP toward the arm portion 80 will be described as upward, and the direction from the arm portion 80 toward the two-axis integrated motor MP will be described as downward.

The arm portion 80 is, for example, a cantilever arm having only a single arm. The actuator 1 is fixed to, for example, a support base (not shown) with the rotation axis AX of the arm portion 80 facing in the Z direction. As shown in FIG. 1, the actuator 1 moves the arm portion 80 in the Z direction (linear motion direction) to move the arm portion 80 up and down in the Z direction, and moves the arm portion 80 in an arbitrary plane orthogonal to the Z direction. , Rotate or rotate the rotary shaft AX in the axial direction to transfer the work to a desired position.

As shown in FIG. 2, the two-axis integrated motor MP includes a stator 10, a first rotor 20, a second rotor 30, a housing 40, a first rotation detection unit 101, and a second rotation detection unit 102. Has. The stator 10, the first rotor 20, and the second rotor 30 are arranged coaxially with each other about the rotation axis AX. The stator 10 is arranged between the first rotor 20 and the second rotor 30. For example, the first rotor 20 is arranged inside the stator 10 in the radial direction and rotates relative to the stator 10. The second rotor 30 is arranged on the outer side in the radial direction of the stator 10 and rotates relative to the stator 10.

As shown in FIG. 3, the stator 10 has a stator core 11, a first exciting coil 12, and a second exciting coil 13. The stator 10 is provided in a cylindrical shape around the rotation shaft AX. The stator core 11 includes a cylindrical back yoke 15, a plurality of first teeth 14 arranged radially inside the back yoke 15, and a plurality of second teeth 16 arranged radially outside the back yoke 15. Has.

The plurality of first teeth 14 are arranged along the inner circumference of the back yoke 15. The plurality of first teeth 14 are connected to the back yoke 15. The first exciting coil 12 is wound around the first teeth 14. The first exciting coil 12 is electrically connected to the first driver 121. The first driver 121 drives the first rotor 20 by supplying the first driving current I1 to the first exciting coil 12.

The rotating magnetic field obtained by exciting the first exciting coil 12 is, for example, three phases. The first exciting coil 12 includes exciting coils for U-phase, V-phase, and W-phase in which the phases of the drive signals are shifted by 120 °.

The plurality of second teeth 16 are arranged along the outer circumference of the back yoke 15. The plurality of second teeth 16 are connected to the back yoke 15. The second exciting coil 13 is wound around the second teeth 16. The second exciting coil 13 is electrically connected to the second driver 122. The second driver 122 drives the second rotor 30 by supplying the second driving current I2 to the second exciting coil 13.

The rotating magnetic field obtained by exciting the second exciting coil 13 is, for example, three phases. The second exciting coil 13 includes exciting coils for U-phase, V-phase, and W-phase in which the phases of the drive signals are shifted by 120 °.

The first driver 121 and the second driver 122 are electrically connected to the controller 120. The controller 120 independently controls the first driver 121 and the second driver 122. The controller 120 independently controls the amount of the first drive current I1 and the amount of the second drive current I2. The rotation angle of the first rotor 20 is controlled by the amount of the first drive current I1. The rotation angle of the second rotor 30 is controlled by the amount of the second drive current I2. The controller 120 independently controls the rotation angle of the first rotor 20 and the rotation angle of the second rotor 30.

The axial length of the plurality of first teeth 14 is longer than the axial length of the plurality of second teeth 16. With this structure, even if the amount of the current of the first drive current I1 and the amount of the current of the second drive current I2 are the same, the torque of the first rotor 20 is not extremely smaller than the torque of the second rotor 30. When the amount of the current of the first drive current I1 and the amount of the current of the second drive current I2 are the same, the plurality of first teeth 14 so that the torque of the first rotor 20 becomes smaller than the torque of the second rotor 30. The axial length of the second teeth 16 is made longer than the axial length of the plurality of second teeth 16. As a result, the controller 120 can easily control the first rotor 20 and the second rotor 30 independently.

As shown in FIG. 2, the first rotor 20 has a first rotor bracket 21, a first rotor core 22 formed of a permanent magnet, and connecting brackets 23 and 24 connected to a nut 51 described later. As shown in FIG. 3, the first rotor bracket 21 is provided in a cylindrical shape around the rotation shaft AX. The first rotor bracket 21 can be said to be a cylindrical output shaft on the inner diameter side. The inner diameter of the first rotor 20 is smaller than the outer diameter of the nut 51 and the spline outer cylinder 61, which will be described later.

The first rotor core 22 has an N-pole magnet portion and an S-pole magnet portion. The north pole magnet portion and the south pole magnet portion are arranged alternately at equal intervals in the rotation direction. The first rotor core 22 rotates according to the rotating magnetic field in which the first exciting coil 12 is excited by the first teeth 14. The first rotor core 22 may be attached to the outer peripheral surface of the first rotor bracket 21, or may be embedded inside the first rotor bracket 21.

As shown in FIG. 2, the connecting bracket 23 is formed in a cylindrical shape and is arranged on the inner peripheral side of the first rotor bracket 21. The connecting bracket 23 has a flange portion 23a formed at a lower end portion in the Z direction and a cushioning member 23b. The cushioning member 23b is arranged on the upper surface of the flange portion 23a in the Z direction. The cushioning member 23b is, for example, elastic rubber. In the present embodiment, the connecting bracket 23 is fixed to the upper end of the first rotor bracket 21 and extends downward along the inner circumference of the first rotor bracket 21. The connecting bracket 24 is fixed to the lower end of the connecting bracket 23 and extends downward from the connecting bracket 23. Therefore, between the first rotor bracket 21 and the nut 51 described later, the connecting brackets 23 and 24 are connected so as to be folded back inward and downward from the upper end of the first rotor bracket 21.

The second rotor 30 has a second rotor bracket 31 and a second rotor core 32 configured by a permanent magnet. The second rotor bracket 31 is arranged on the outer peripheral side of the second rotor core 32. As shown in FIG. 3, the second rotor bracket 31 is provided in a cylindrical shape around the rotation shaft AX. The second rotor bracket 31 can also be said to be a cylindrical output shaft on the outer diameter side.

The second rotor core 32 has an N-pole magnet portion and an S-pole magnet portion. The north pole magnet portion and the south pole magnet portion are arranged alternately at equal intervals in the rotation direction. The second rotor core 32 rotates according to the rotating magnetic field in which the second exciting coil 13 is excited by the second teeth 16. The second rotor core 32 may be attached to the inner peripheral surface of the second rotor bracket 31, or may be embedded inside the second rotor bracket 31.

As shown in FIG. 2, the first bearing 25 is arranged at a position where it does not overlap with the first teeth 14 and the first exciting coil 12 in the Z direction. The first bearing 25 is located between the back yoke 15 and the first rotor bracket 21, and rotatably supports the first rotor 20. The first bearing 25 is a plurality of combination bearings having a bearing 25a and a bearing 25b. It is desirable to provide a non-magnetic slit in the back yoke 15 that separates the inside in the radial direction and the outside in the radial direction. The first bearing 25 is positioned and fixed by a protrusion on the outer periphery of the first rotor bracket 21.

The second bearing 35 is arranged at a position where it does not overlap with the second teeth 16 and the second exciting coil 13 in the Z direction. The second bearing 35 is located between the back yoke 15 and the second rotor bracket 31, and rotatably supports the second rotor 30. The second bearing 35 is a plurality of combination bearings having a bearing 35a and a bearing 35b. The second bearing 35 is positioned and fixed by a protrusion on the inner circumference of the second rotor bracket 31.

The first rotation detection unit 101 is provided at a position where it does not overlap with the first bearing 25 in the Z direction. The first rotation detection unit 101 detects the rotation angle of the first rotor bracket 21 with respect to the housing 40 and supplies it to the controller 120 (see FIG. 3).

The first rotation detection unit 101 is, for example, a resolver. The first rotation detection unit 101 includes a resolver stator 101a and a resolver rotor 101b. The resolver rotor 101b is fixed to the outer peripheral surface of the first rotor bracket 21. The resolver stator 101a is arranged at positions facing each other in the radial direction of the resolver rotor 101b. The controller 120 adjusts the amount of the first drive current I1 based on the detection result of the first rotation detection unit 101 so that the first rotor 20 can obtain a desired rotation angle.

The second rotation detection unit 102 is provided at a position where it does not overlap with the second bearing 35 in the Z direction. The second rotation detection unit 102 detects the rotation angle of the second rotor bracket 31 with respect to the housing 40 and supplies it to the controller 120 (see FIG. 3).

The second rotation detection unit 102 is, for example, a resolver. The second rotation detection unit 102 includes a resolver rotor 102a and a resolver stator 102b. The resolver rotor 102a is fixed to the inner peripheral surface of the second rotor bracket 31. The resolver rotor 102a is arranged at positions facing each other in the radial direction of the resolver stator 102b. The controller 120 adjusts the amount of the second drive current I2 based on the detection result of the second rotation detection unit 102 so that the second rotor 30 can obtain a desired rotation angle.

The first rotation detection unit 101 and the second rotation detection unit 102 are covered with a ring plate-shaped cover 99. The annular plate-shaped cover 99 suppresses foreign matter from entering the periphery of the first rotation detection unit 101 and the second rotation detection unit 102.

The ball screw 50 has a nut 51, a screw shaft (first portion) 52, and a rolling element (not shown). The nut 51 is arranged below the first rotor bracket 21. That is, the nut 51 is arranged on the lower outer side in the axial direction with respect to the first rotor 20. The nut 51 is arranged coaxially with the first rotor 20 and rotates with the rotation of the first rotor 20. As shown in FIG. 1, the nut 51 has a flange portion 51a. The flange portion 51a is fixed to the connecting bracket 24 by the fixing member 51b. The nut 51 is connected to the first rotor bracket 21 via the connecting bracket 24 and the connecting bracket 23. For example, the first rotor bracket 21 and the connecting bracket 23 are fixed by a fixing member 26. Further, the connecting bracket 23 and the connecting bracket 24 are fixed by a fixing member 27. As the fixing members 26 and 27, for example, bolts and the like are used. The nut 51 is integrally provided with the first rotor bracket 21 by the connecting brackets 23 and 24. Therefore, when the first rotor 20 rotates, the nut 51 rotates integrally with the first rotor 20 in the axial direction of the rotation shaft AX.

The screw shaft 52 projects downward from the first rotor 20. The screw shaft 52 includes a screw portion 52a having a thread formed on the outer peripheral surface thereof and a clamped portion 52b. A nut 51 is screwed into the screw portion 52a. When the nut 51 rotates, the screw shaft 52 moves in the axial direction (Z direction) according to the rotation. A rolling element is arranged inside the nut 51. The clamped portion 52b has a smaller outer diameter than the thread of the threaded portion 52a.

A stopper 53 is attached to the lower end of the screw shaft 52 by a nut 54. The stopper 53 is a ring-shaped member. The stopper 53 is inserted into the screw shaft 52. An annular cushioning member 53a is arranged on the upper side of the stopper 53 in the Z direction. The cushioning member 53a is, for example, elastic rubber. The outer diameter r2 of the cushioning member 53a and the stopper 53 is larger than the inner diameter r1 of the flange portion 150a. Therefore, the stopper 53 comes into contact with the flange portion 150a via the cushioning member 53a when the screw shaft 52 is raised by a predetermined length. Thereby, the stopper 53 can regulate the screw shaft 52 from rising beyond a predetermined length.

The ball spline 60 has a spline outer cylinder 61, a shaft (second portion) 62, and a rolling element (not shown). The spline outer cylinder 61 is arranged above the second rotor bracket 31. That is, the spline outer cylinder 61 is arranged outside the upper side in the axial direction with respect to the first rotor 20. The spline outer cylinder 61 is arranged coaxially with the second rotor 30 and rotates with the rotation of the second rotor 30. The spline outer cylinder 61 is connected to the second rotor bracket 31 via the connecting bracket 33. For example, the second rotor bracket 31 and the connecting bracket 33 are fixed by a fixing member 36. As the fixing member 36, for example, a bolt or the like is used. The spline outer cylinder 61 is integrally provided with the second rotor bracket 31 by the connecting bracket 33. Therefore, when the second rotor 30 rotates, the spline outer cylinder 61 rotates integrally with the second rotor 30 in the axial direction of the rotation shaft AX.

A connecting bracket 34 is arranged at the upper end of the spline outer cylinder 61. The connecting bracket 34 is fixed to the connecting bracket 33 by a fixing member 37. As the fixing member 37, for example, a bolt or the like is used.

As shown in FIG. 1, the shaft 62 projects upward from the first rotor 20. The shaft 62 is inserted on the inner diameter side of the spline outer cylinder 61. The lower end side of the shaft 62 is integrally connected to the screw shaft 52 via a connecting portion 56. In the present embodiment, the screw shaft 52 and the shaft 62 are press-fitted at the connecting portion 56 to integrally form the shaft member SF. As shown in FIG. 2, the connecting portion 56 is provided with a hole portion 56a for allowing air to escape when the screw shaft 52 and the shaft 62 are press-fitted. As shown in FIG. 4, the shaft 62 is provided with a plurality of groove portions 62a parallel to the axial direction of the rotating shaft AX arranged side by side in the circumferential direction. The shaft 62 has a reduced diameter portion 62b at the upper end. The reduced diameter portion 62b is fixed to the arm mounting member 70 described later.

Further, on the inner peripheral surface of the spline outer cylinder 61, a plurality of convex portions corresponding to the groove portions 62a of the shaft 62 are provided side by side in the circumferential direction. By inserting the convex portion of the spline outer cylinder 61 into the groove portion 62a of the shaft 62, the relative movement of the spline outer cylinder 61 and the shaft 62 in the axial direction of the rotating shaft AX is restricted, and the axis of the rotating shaft AX is restricted. Relative movement between the spline outer cylinder 61 and the shaft 62 in the direction is allowed. Therefore, when the spline outer cylinder 61 rotates, the shaft 62 moves in the axial direction (Z direction) according to the rotation. Further, when the screw shaft 52 moves in the axial direction of the rotating shaft AX due to the rotation of the nut 51 without rotating the spline outer cylinder 61, the shaft 62 moves in the axial direction together with the screw shaft 52. A rolling element is arranged inside the spline outer cylinder 61.

The housing 40 includes a motor housing 41, a nut housing 42, and a spline outer cylinder housing 43. The motor housing 41 is formed in a cylindrical shape, for example, and accommodates a two-axis integrated motor MP.

The nut housing 42 has a flange portion 42a and a tubular portion 42b. As shown in FIG. 2, the flange portion 42a is formed in an annular shape and is fixed to the lower end of the motor housing 41 by the fixing member 44. A fixing member 45 for fixing the stator core fixing housing 17 is attached to the flange portion 42a. The fixing member 45 fixes the stator core 11 to the housing 40. The tubular portion 42b extends downward from the inner circumference of the flange portion 42a. As shown in FIG. 1, the tubular portion 42b accommodates the nut 51 of the ball screw 50.

Further, as shown in FIG. 2, the nut housing 42 holds the third bearing 28 between the nut housing 42 and the connecting bracket 24. The third bearing 28 rotatably supports the nut 51. The third bearing 28 is, for example, a rolling bearing. The third bearing 28 is supported by the flange portion 42a via a wave washer 29a and a pressing member 29b. The third bearing 28 is pressed against the cylindrical portion 42b by the wave washer 29a and the pressing member 29b. For example, when the object is supported by the arm portion 80 and the center of gravity of the load of the arm portion 80 and the object does not match the rotation axis AX, or when the arm portion 80 and the object receive a rotation moment, the shaft member SF causes the rotation axis AX. There is a possibility of receiving a force in the direction of tilting. On the other hand, since the third bearing 28 is radially supported by the nut housing 42 and the fixing base ST via the wave washer 29a and the pressing member 29b, the third bearing 28 is supported in the radial direction in the direction orthogonal to the axial direction of the rotating shaft AX. The displacement or vibration of the nut 51 is suppressed.

As shown in FIG. 1, the spline outer cylinder housing 43 has a flange portion 43a, a first tubular portion 43b, and a second tubular portion 43c. The flange portion 43a is formed in an annular shape and is fixed to the upper end of the motor housing 41 by a fixing member 46. As shown in FIG. 2, the flange portion 43a is fixed to the fixing base ST by the fixing member 47. By fixing the flange portion 43a to the fixed base ST, the actuator 1 is fixed to the fixed base ST.

As shown in FIG. 1, the first tubular portion 43b is formed in a cylindrical shape and extends upward from the inner circumference of the flange portion 43a. The first cylindrical portion 43b accommodates the spline outer cylinder 61 of the ball spline 60. As shown in FIG. 4, the first cylindrical portion 43b is connected to the second tubular portion 43c via the first step portion 43d and the second step portion 43e.

As shown in FIG. 4, the first cylindrical portion 43b holds the fourth bearing 38 with the connecting bracket 34 in the first step portion 43d. The fourth bearing 38 rotatably supports the spline outer cylinder 61. The fourth bearing 38 is, for example, a rolling bearing. The fourth bearing 38 is supported by the second stage portion 43e via a wave washer 39a and a pressing member 39b. The fourth bearing 38 is pressed against the connecting bracket 34 by the wave washer 39a and the pressing member 39b. Further, the fourth bearing 38 is supported in the radial direction by the spline outer cylinder housing 43 and the fixing base ST (see FIG. 1). For example, when the object is supported by the arm portion 80 and the center of gravity of the load of the arm portion 80 and the object does not match the rotation axis AX, or when the arm portion 80 and the object receive a rotation moment, the shaft member SF causes the rotation axis AX. There is a possibility of receiving a force in the direction of tilting. On the other hand, since the fourth bearing 38 is supported in the radial direction by the housing 43 for the spline outer cylinder and the fixing base ST via the wave washer 39a and the pressing member 39b, the direction orthogonal to the axial direction of the rotating shaft AX. The displacement or vibration of the spline outer cylinder 61 is suppressed.

As shown in FIG. 4, the second stage portion 43e is provided with an air supply portion 43f. An air joint for air purging can be attached to the air supply unit 43f. The air supply unit 43f communicates between the outside and the space formed between the second cylindrical portion 43c and the shaft 62. The air supply unit 43f is provided with a closing bolt 43 g. The bolt 43g is detachably attached to the air supply unit 43f. The bolt 43g is closed so that foreign matter such as dust does not enter the air supply unit 43f.

The second tubular portion 43c is formed in a cylindrical shape and extends upward from the upper end of the first tubular portion 43b. The diameter of the second tubular portion 43c is smaller than that of the first tubular portion 43b. The second cylindrical portion 43c is arranged so as to cover a part of the outer peripheral surface of the shaft 62. For example, as shown in FIG. 1, the dimensions of the second cylindrical portion 43c in the axial direction of the rotating shaft AX are the upper end and the shaft of the second tubular portion 43c with the shaft member SF arranged at the lowermost end. It is set so that the upper end of the member SF (the upper end of the shaft 62) is flush with the upper end.

The arm mounting member 70 is connected to the tip (upper end) of the shaft 62. The arm mounting member 70 has a connecting portion 71, a cylindrical portion 72, and a lid portion 73. The connecting portion 71 is connected to the reduced diameter portion 62b of the shaft 62. The connecting portion 71 includes a penetrating portion 71a for penetrating the reduced diameter portion 62b, a recess 71b for inserting the connecting member 74, an arm mounting surface 71c for mounting the arm portion 80, and a lid mounting surface 71d for mounting the lid portion 73. Have.

The penetrating portion 71a is formed corresponding to the shape of the reduced diameter portion 62b. The recess 71b forms a space between the recess 71b and the reduced diameter portion 62b in a state where the reduced diameter portion 62b is inserted into the penetrating portion 71a. A connecting member 74 is arranged in this space. The connecting member 74 has a concave member 74a and a convex member 74b on which opposing tapered surfaces of equal inclination are formed. The concave member 74a is formed in an annular shape and is arranged in contact with the inner circumference of the recess 71b. The convex member 74b is formed in an annular shape and is inserted inside the concave portion 71b. The inner circumference of the convex member 74b is arranged in contact with the outer circumference of the reduced diameter portion 62b. The connecting member 74 is fixed by pressing the convex member 74b into the concave member 74a by the fixing member 75. As a result, between the inner circumference of the concave member 71b and the outer circumference of the concave member 74a, between the tapered surface of the concave member 74a and the tapered surface of the convex member 74b, and the inner circumference of the convex member 74b and the outer circumference of the reduced diameter portion 62b. Is in a state of being pressed against each other. Therefore, a frictional force is generated between the concave portion 71b, the concave member 74a, the convex member 74b, and the reduced diameter portion 62b, respectively. Due to this frictional force, the arm mounting member 70 is integrally connected to the reduced diameter portion 62b.

The arm portion 80 is attached to the arm attachment surface 71c. The arm mounting surface 71c is provided with an insertion hole 71e into which a fixing member (not shown) for fixing the arm portion 80 is inserted. The lid portion 73, which will be described later, is attached to the lid portion mounting surface 71d.

The tubular portion 72 is formed in a cylindrical shape and is provided in a state of extending from the connecting portion 71 toward the spline outer cylinder 61 side (downward). The tubular portion 72 is arranged outside the second tubular portion 43c of the spline outer cylinder housing 43 in the radial direction of the rotation shaft AX, and accommodates the tip end (upper end) of the second tubular portion 43c. The tubular portion 72 has a step portion 72a at the lower end portion. The step portion 72a has a configuration in which the lower end of the inner peripheral surface is enlarged in diameter. A seal portion 77 is arranged on the step portion 72a. The seal portion 77 seals a gap 72b formed between the tubular portion 72 and the second tubular portion 43c of the spline outer cylinder housing 43. Examples of the seal portion 77 include a structure in which a U-shaped or U-shaped member is formed in a ring shape in a cross-sectional view. The seal portion 77 is formed using, for example, an elastically deformable material. The seal portion 77 is arranged between the inner peripheral surface of the step portion 72a and the outer peripheral surface of the second tubular portion 43c in a state of being elastically deformed. The seal portion 77 protects the shaft 62 from the outside. A protrusion protruding inward is formed at the lower end of the step portion 72a. The protrusion prevents the seal portion 77 from falling. Further, when the power is cut off, the rotation of the shaft 62 (shaft member SF) is suppressed by the seal resistance of the seal portion 77.

Further, as shown in FIGS. 1 and 4, a cylindrical gap 72b is formed between the tubular portion 72 and the second tubular portion 43c. Since the labyrinth structure is formed between the shaft 62 and the outside by the gap 72b, the dustproof property and the waterproof property are enhanced.

The lid portion 73 is attached to the lid portion mounting surface 71d of the connecting portion 71 by a fixing member 76 such as a bolt. The lid portion 73 protects the reduced diameter portion 62b of the shaft 62 from the external environment.

As shown in FIG. 5, the clamp mechanism 130 includes a shaft member SF, a collet 132, and a cylinder 134. As shown in FIG. 5, the collet 132 includes a grip portion 132A that can be deformed in the radial direction and a flange portion 132B having a substantially tubular shape. The grip portion 132A is formed with four slits in the Z direction. The cross-sectional view shown in FIG. 5 shows a cross section cut along the slit. The slits are formed at different positions by 90 degrees in the circumferential direction. As a result, the grip portion 132A can be elastically deformed in the radial direction. The number, shape and position of the pickpockets are not particularly limited. The slitting may be formed so that the grip portion 132A can be elastically deformed in the radial direction.

A screw shaft 52 is inserted into the collet 132. The collet 132 includes a first tapered surface 132a, a second tapered surface 132b, a concave portion 132c, and an inner peripheral surface 132d. The first tapered surface 132a is an outer peripheral surface of the grip portion 132A. The first tapered surface 132a is an inclined surface whose outer diameter decreases toward the lower side in the Z direction. That is, the first tapered surface 132a has a substantially conical shape.

The second tapered surface 132b is an outer peripheral surface of the flange portion 132B on the upper side in the Z direction. The second tapered surface 132b is an inclined surface whose outer diameter decreases toward the upper side in the Z direction. That is, the second tapered surface 132b has a substantially conical shape. The recess 132c is a groove formed on the outer peripheral surface of the flange portion 132B. The recess 132c is formed between the first tapered surface 132a and the second tapered surface 132b in the Z direction. The inner peripheral surface 132d is a surface of the screw shaft 52 facing the clamped portion 52b. The collet 132 is arranged so that the inner peripheral surface 132d faces the clamped portion 52b of the screw shaft 52 even when the screw shaft 52 moves to the maximum in the axial direction.

As shown in FIG. 5, the cylinder 134 includes a piston 136, a cylinder tube 138, a first seal member 160, and a second seal member 162. Further, the cylinder 134 includes a gas supply portion 163, a fixing member 144, a stopper portion 146, a screw shaft housing 150, and a spring 156.

The shaft member SF is inserted into the piston 136. The piston 136 includes an inclined surface 136a, a first outer surface 136b, a second outer surface 136c, a groove portion 136d, a lower surface 136e, a recess 136f, and an upper surface 136g.

The inclined surface 136a is an inner peripheral surface on the upper side of the piston 136 in the Z direction. The inclined surface 136a is inclined so that the diameter increases toward the upper side in the Z direction. The inclined surface 136a overlaps with the first tapered surface 132a in the Z direction. With such a configuration, the inclined surface 136a can come into contact with the first tapered surface 132a when the piston 136 moves upward in the Z direction. Then, when the inclined surface 136a comes into contact with the first tapered surface 132a, the first tapered surface 132a can be pressed inward in the radial direction. That is, the inclined surface 136a is a chuck portion capable of pressing the grip portion 132A inward in the radial direction. The inclined surface 136a faces the first tapered surface 132a. That is, the inclined surface 136a and the first tapered surface 132a have substantially the same inclination. The inclined surface 136a is arranged so as to overlap the first tapered surface 132a in the radial direction. As a result, the axial dimension of the space occupied by the piston 136 and the collet 132 can be reduced.

The first outer surface 136b and the second outer surface 136c are the outer surfaces of the piston 136. The first outer surface 136b is located above the second outer surface 136c in the Z direction. The second outer surface 136c has a larger diameter than the first outer surface 136b. The first outer surface 136b and the second outer surface 136c are arranged so as to overlap the first tapered surface 132a in the radial direction. The groove portion 136d is a square groove formed on the first outer surface 136b. The groove portion 136d is formed along the circumferential direction of the first outer surface 136b. The lower surface 136e is the lower surface of the piston 136 in the Z direction. A recess 136f recessed upward in the Z direction is formed on the lower surface 136e. The upper surface 136 g is the upper surface of the piston 136 in the Z direction.

The cylinder tube 138 is a substantially tubular member that accommodates the piston 136. A tubular portion 138a, an outer diameter side flange portion 138b, an inner diameter side flange portion 138c, a groove portion 138d, a first inner side surface 138e, a second inner side surface 138f, and a gas supply path 138g are provided. The tubular portion 138a is a tubular member. The outer diameter side flange portion 138b and the inner diameter side flange portion 138c are connected to the upper end of the tubular portion 138a in the Z direction. The outer diameter side flange portion 138b is a flange surface formed in an annular shape. The outer diameter side flange portion 138b is fixed to the lower end of the tubular portion 42b by the fixing member 140. The inner diameter side flange portion 138c is formed in an annular shape and is arranged radially inside the outer diameter side flange portion 138b. A stepped surface 142 is formed on the inner diameter side flange portion 138c. The stepped surface 142 is formed at the upper end of the inner diameter side flange portion 138c in the Z direction. The stepped surface 142 has an annular shape when viewed from the upper side in the Z direction.

The first inner side surface 138e is a side surface on the inner side in the radial direction of the inner diameter side flange portion 138c. The first inner surface 138e faces the first outer surface 136b. The second inner side surface 138f is a side surface inside the cylindrical portion 138a in the radial direction. The diameter of the second inner surface 138f is larger than the diameter of the first inner surface 138e. The second inner surface 138f faces the second outer surface 136c. The first inner side surface 138e and the second inner side surface 138f are arranged so as to overlap the first tapered surface 132a in the radial direction. The groove portion 138d is a square groove formed on the second inner side surface 138f. The groove portion 138d is formed along the circumferential direction of the second inner side surface 138f.

As shown in FIG. 5, the gas supply path 138 g is an opening penetrating from the outside of the cylinder tube 138 to the inside of the cylinder tube 138. A gas supply pipe 158 is connected to the gas supply path 138 g. The gas supply path 138 g and the gas supply pipe 158 are fixed with screws, for example, via sealing tape.

The first seal member 160 is an O-ring. The first seal member 160 is arranged in the groove 136d. The first seal member 160 fills the gap between the first outer surface 136b and the first inner surface 138e. According to this, the gap between the first outer surface 136b and the first inner surface 138e is sealed.

The second seal member 162 is an O-ring. The second seal member 162 is arranged in the groove portion 138d. The second seal member 162 fills the gap between the second outer surface 136c and the second inner surface 138f. According to this, the gap between the second outer surface 136c and the second inner surface 138f is sealed. With such a configuration, the gas supply pipe 158, the gas supply path 138 g, the first outer surface 136b, the second outer surface 136c, the first inner side surface 138e, the second inner side surface 138f, the first seal member 160 and the second seal member A pressure chamber 139 surrounded by 162 is formed.

As shown in FIG. 6, the gas supply unit 163 is a compressor that supplies compressed air 164. The gas supply unit 163 is connected to the gas supply pipe 158. As shown in FIG. 3, the gas supply unit 163 is electrically connected to the controller 120. The controller 120 controls the timing at which the gas supply unit 163 supplies the compressed air 164. The gas supplied by the gas supply unit 163 is not limited to the compressed air 164. The gas supply unit 163 may supply compressed nitrogen, for example.

The fixing member 144 is a ring-shaped plate member. The shaft member SF is inserted into the fixing member 144. The fixing member 144 is arranged so that the lower surface on the outer side in the radial direction comes into contact with the stepped surface 142. Further, the fixing member 144 has an end portion inside in the radial direction inserted into the recess 132c.

The stopper portion 146 is a ring-shaped member. The shaft member SF is inserted into the stopper portion 146. The stopper portion 146 includes an inclined surface 146a facing the second tapered surface 132b. As a result, the stopper portion 146 can limit the movement of the collet 132 upward in the Z direction. Further, the stopper portion 146 is fixed to the inner diameter side flange portion 138c by the fixing member 148 in a state where the fixing member 144 is sandwiched between the stepped surface 142. Therefore, the stopper portion 146 fixes the position of the fixing member 144 in the Z direction. The end of the fixing member 144 on the inner diameter side is inserted into the recess 132c. According to this, the fixing member 144 can limit the movement of the collet 132 downward in the Z direction. With such a configuration, the position of the collet 132 in the Z direction is determined.

The screw shaft housing 150 is fixed to the fixing base ST via the cylinder tube 138, the nut housing 42, the motor housing 41, and the spline outer cylinder housing 43. The screw shaft housing 150 has a flange portion 150a, a flange surface 150b, a tubular portion 150c, a recess 150d, and a lid member 150e. The flange portion 150a is formed in an annular shape and is fixed to the lower end of the tubular portion 138a by the fixing member 152. The flange surface 150b is the upper surface of the flange portion 150a in the Z direction. The flange surface 150b faces the lower surface 136e. The tubular portion 150c extends downward from the inner circumference of the flange portion 150a. As shown in FIG. 5, the tubular portion 150c accommodates the lower end of the screw shaft 52. The recess 150d is a recess recessed downward in the Z direction from the flange surface 150b. The lid member 150e is a member that closes the lower side of the tubular portion 150c in the Z direction. The lid member 150e is fixed to the lower end surface of the tubular portion 150c in the Z direction by the fixing members 153 and 154. As a result, it is possible to prevent foreign matter from entering the inside of the screw shaft housing 150 from the lower side in the Z direction.

The spring 156 is a compression coil spring. One end of the spring 156 comes into contact with the bottom surface of the recess 136f. The other end of the spring 156 comes into contact with the bottom surface of the recess 150d. Therefore, the spring 156 is compressed by the bottom surface of the recess 136f and the bottom surface of the recess 150d. Since the screw shaft housing 150 is fixed to the fixing base ST, the bottom surface of the recess 150d does not move downward in the Z-axis direction. Therefore, the spring 156 presses the piston 136 upward in the Z direction. The spring 156 is assumed to be a compression coil spring, but the spring 156 is not limited to this. The spring 156 may be an elastic member that urges the piston 136 in the direction in which the piston 136 approaches the grip portion 132A. The spring 156 may be, for example, a square spring or a conical spring. Further, a plurality of springs 156 may be arranged.

In the actuator 1, when the arm portion 80 is moved in the axial direction (Z direction) of the rotation axis AX, the controller 120 moves the first rotor 20 in the axial direction of the rotation axis AX without rotating the second rotor 30. Rotate to one or the other. In this case, the nut 51 of the ball screw 50 rotates integrally with the rotation of the first rotor 20. Due to the rotation of the nut 51, the nut 51 and the screw shaft 52 rotate relatively in the axial direction of the rotation shaft AX, so that the screw shaft 52 moves in the Z direction. By moving the screw shaft 52, the shaft 62 integrally connected to the screw shaft 52, that is, the shaft member SF moves in the Z direction. Due to the movement of the shaft member SF, the arm mounting member 70 and the arm portion 80 connected to the upper end of the shaft 62 move in the Z direction. When the shaft member SF is moved upward, as shown in FIG. 7, the stopper 53 at the lower end of the screw shaft 52 comes into contact with the lower end of the flange portion 150a, and the upward movement of the shaft member SF is restricted. Further, when the shaft member SF is moved downward, as shown in FIG. 2, the cushioning member 23b of the connecting bracket 23 comes into contact with the lower end of the connecting portion 56, and the downward movement of the shaft member SF is restricted. The cushioning member 23b may be fixed to the lower end of the connecting portion 56.

In the actuator 1, when the arm portion 80 is moved in the direction around the axis of the rotation axis AX, the controller 120 rotates the first rotor 20 and the second rotor 30 in synchronization with each other. In this case, the nut 51 of the ball screw 50 rotates integrally with the rotation of the first rotor 20. Further, as the second rotor 30 rotates, the spline outer cylinder 61 of the ball spline 60 rotates integrally. The rotation of the spline outer cylinder 61 causes the shaft 62 to rotate integrally with the spline outer cylinder 61. The rotation of the shaft 62 causes the screw shaft 52 connected to the shaft 62, that is, the shaft member SF to rotate. Therefore, in the ball screw 50, the nut 51 and the screw shaft 52 do not rotate relatively, and the screw shaft 52 of the ball screw 50 does not move in the Z direction with respect to the nut 51. That is, the shaft member SF rotates in the axial direction of the rotation shaft AX without moving in the Z direction. Due to the rotation of the shaft member SF, the arm mounting member 70 and the arm portion 80 rotate in the axial direction of the rotation shaft AX.

As shown in FIG. 5, when the shaft member SF is clamped in the clamping mechanism 130, the spring 156 pushes the lower surface 136e of the piston 136 upward in the Z direction. As a result, the piston 136 moves upward in the Z direction, and the inclined surface 136a is pressed against the first tapered surface 132a. Then, the grip portion 132A is elastically deformed inward in the radial direction, and the inner peripheral surface 132d of the collet 132 is pressed against the clamped portion 52b.

As shown in FIG. 6, when the shaft member SF is unclamped in the clamp mechanism 130, the gas supply unit 163 sends compressed air 164 of a predetermined pressure to the pressure chamber 139 via the gas supply pipe 158 and the gas supply path 138 g. Supply. As a result, the pressure in the pressure chamber 139 rises. The compressed air 164 presses 136 g of the upper surface of the piston 136 downward in the Z direction. As a result, the piston 136 moves downward in the Z direction, and the inclined surface 136a separates from the first tapered surface 132a. Then, the inner peripheral surface 132d of the collet 132 separates from the clamped portion 52b. The predetermined pressure is such that the force of the compressed air 164 pressing the piston 136 is larger than the force of the spring 156 pressing the piston 136 when the inner peripheral surface 132d of the collet 132 is in contact with the clamped portion 52b. The pressure is set to be.

Here, as described in Patent Document 1, the clamp mechanism is known to have a configuration in which a clamp portion such as a disc spring and a piston for pressing the clamp portion are arranged side by side in the axial direction of the shaft member. In such a configuration, there is a problem that the dimension of the clamp mechanism in the axial direction becomes large.

On the other hand, in the clamp mechanism 130 of the present embodiment, the inclined surface 136a of the piston 136 is arranged on the radial outer side of the first tapered surface 132a of the collet 132. Then, the cylinder tube 138 is arranged on the radial outer side of the piston 136. According to this configuration, the dimension of the clamp mechanism 130 in the axial direction can be reduced as compared with the configuration in which the clamp portion (belleville spring or the like) and the piston pressing the clamp portion are arranged side by side in the axial direction. As a result, the axial dimension of the actuator 1 can be reduced.

In the clamp mechanism 130 of the present embodiment, the spring 156 clamps the shaft member SF by pressing the piston 136 upward in the Z direction. Then, the clamp mechanism 130 unclamps the piston 136 by pressing the compressed air 164 downward in the Z direction. With such a configuration, the clamp mechanism 130 can clamp the shaft member SF even when the supply of the compressed air 164 is stopped due to a power failure. That is, the clamp mechanism 130 can prevent the shaft member SF from falling downward in the Z direction in the event of a power failure. Further, even when the inclined surface 136a bites into the first tapered surface 132a, the inclined surface 136a can be separated from the first tapered surface 132a by further increasing the pressure of the compressed air 164.

FIG. 8 is a flowchart showing an example of the operation procedure of the actuator of the present embodiment. Hereinafter, an example of the operation procedure of the actuator 1 of the present embodiment will be described with reference to FIG. In the following description, a state in which the shaft member SF is clamped to the collet 132 will be described as an initial state.

First, the controller 120 controls the first driver 121 to supply a predetermined current to the first exciting coil 12 (first shaft member holding step ST10). The predetermined current is a current value that causes the first rotor 20 to generate a predetermined torque. The predetermined torque is a torque that is opposite to the torque that the shaft member SF rotates the nut 51 by its own weight and has the same magnitude when the shaft member SF is unclamped. According to this, even when the shaft member SF is unclamped, it is possible to prevent the shaft member SF from falling while rotating due to the weight of the shaft member SF.

Next, the controller 120 controls the gas supply unit 163 to supply the compressed air 164 to the pressure chamber 139 (unclamp step ST12). As a result, the compressed air 164 presses 136 g of the upper surface of the piston 136 downward in the vertical direction. The pressure of the compressed air 164 is adjusted so that the force of the compressed air 164 pressing the piston 136 downward in the vertical direction is greater than the force of the spring 156 pressing the piston 136 upward in the vertical direction. Therefore, the piston 136 moves downward in the vertical direction. As a result, the inclined surface 136a can be separated from the first tapered surface 132a to unclamp the shaft member SF.

Next, the controller 120 controls the two-axis integrated motor MP so that the arm portion 80 has a predetermined height and a predetermined rotation position (drive step ST14). More specifically, the controller 120 controls the first driver 121 to rotate the first rotor 20 until the arm portion 80 reaches a predetermined height. Further, the controller 120 controls the first driver 121 and the second driver 122 to rotate the first rotor 20 and the second rotor 30 in synchronization until the arm portion 80 reaches a predetermined rotation position.

Next, the controller 120 controls the first driver 121 to supply a predetermined current to the first exciting coil 12 (second shaft member holding step ST16). The second shaft member holding step ST16 is the same as the first shaft member holding step ST10.

Next, the controller 120 controls the gas supply unit 163 to stop the supply of the compressed air 164 (clamp step ST18). As a result, the pressure in the pressure chamber 139 drops, and the spring 156 moves the piston 136 upward in the vertical direction. Therefore, the inclined surface 136a presses the first tapered surface 132a. As a result, the first tapered surface 132a can be elastically deformed inward in the radial direction to clamp the clamped portion 52b of the screw shaft 52.

Next, the controller 120 controls the first driver 121 to stop the current supplied to the first exciting coil 12 (shaft member holding stop step ST20). By such a procedure, the actuator 1 can clamp the shaft member SF even when the current is not supplied to the first exciting coil 12. That is, the actuator 1 can prevent the shaft member SF from falling downward in the Z direction even during a power failure.

Although preferred embodiments of the present invention have been described above, the present invention is not limited to those described in the above embodiments. For example, in the above embodiment, PM (Permanent Magnet) type rotors are used as the rotors of the first rotor 20 and the second rotor 30, but as the rotors of the first rotor 20 and the second rotor 30. , VR (Variable Reluctance) type rotor may be used. Further, a liquid supply unit such as a pump may be used instead of the gas supply unit 163 to supply the liquid to the inside of the cylinder tube 138. In this case, the liquid supply unit may adjust the pressure of the liquid so that the pressure of the liquid supplied to the cylinder tube 138 becomes a predetermined pressure.

Further, in the above embodiment, the nut 51 of the ball screw 50 is connected to the inner first rotor 20, and the spline outer cylinder 61 of the ball spline 60 is connected to the outer second rotor 30, but the present invention is limited to this. Not done. For example, the spline outer cylinder 61 of the ball spline 60 may be connected to the inner first rotor 20, and the nut 51 of the ball screw 50 may be connected to the outer second rotor 30.

Further, in the above embodiment, the ball spline 60 is arranged on the upper side and the ball screw 50 is arranged on the lower side with respect to the two-axis integrated motor MP, but the present invention is not limited to this. For example, the ball screw 50 may be arranged on the upper side and the ball spline 60 may be arranged on the lower side of the two-axis integrated motor MP.

Further, in the above embodiment, the clamp mechanism 130 is applied to the actuator 1 capable of moving the shaft member SF in the axial direction and rotating the shaft member SF, but is not limited thereto. The clamp mechanism 130 may be applied to, for example, an actuator in which the shaft member SF can be moved only in the axial direction. Further, the clamp mechanism 130 may be applied to, for example, an actuator in which the shaft member SF cannot be moved in the axial direction and the shaft member SF can be rotated.

Further, in the above embodiment, the spring 156 is a compression coil spring, but the spring 156 is not limited to this. The spring 156 may be any as long as it can be urged so that the inclined surface 136a is in contact with the first tapered surface 132a. The spring 156 may be, for example, a tension spring that is arranged on the upper side of the piston 136 in the Z direction and urges the piston 136 on the upper side in the Z direction.

The clamp mechanism 130 of the present embodiment includes a shaft member SF, a collet 132, and a cylinder 134. The collet 132 has a tubular shape through which the shaft member SF penetrates. The cylinder 134 has a cylindrical piston 136 through which the shaft member SF penetrates, a cylinder tube 138 that accommodates the piston 136, and an elastic member (spring 156) that urges the piston 136. The piston 136 has a chuck portion (inclined surface 136a) that presses the collet 132 against the shaft member SF by coming into contact with the outer peripheral surface (first tapered surface 132a) of the collet 132 by an elastic member (spring 156). The collet 132 separates from the shaft member SF when gas is supplied to the inside of the cylinder tube 138.

According to this configuration, the spring 156 can be urged so that the inclined surface 136a is in contact with the first tapered surface 132a of the collet 132. Then, the inclined surface 136a can clamp the shaft member SF by pressing the inner peripheral surface 132d of the collet 132 against the clamped portion 52b. Further, since the inclined surface 136a is in contact with the first tapered surface 132a, it overlaps with the first tapered surface 132a in the radial direction. With such a configuration, the axial dimension of the clamp mechanism 130 can be reduced. Further, the shaft member SF can be unclamped by supplying gas to the inside of the cylinder tube 138.

The clamp mechanism 130 of the present embodiment is a tapered surface whose diameter decreases as the outer peripheral surface (first tapered surface 132a) approaches the inclined surface 136a. The inclined surface 136a is an inclined surface facing the outer peripheral surface (first tapered surface 132a).

According to this configuration, the inclined surface 136a can come into surface contact with the first tapered surface 132a when gas is not supplied to the inside of the cylinder tube 138. As a result, the frictional force generated between the collet 132 and the piston 136 can be increased as compared with the case where the first tapered surface 132a and the inclined surface 136a are in line contact or point contact. Therefore, when the collet 132 clamps the shaft member SF, it is possible to prevent the first tapered surface 132a and the inclined surface 136a from slipping.

In the clamp mechanism 130 of the present embodiment, when gas is supplied to the inside of the cylinder tube 138, the outer peripheral surface (first tapered surface 132a) overlaps the inclined surface 136a in the radial direction.

According to this, the axial dimension of the space occupied by the piston 136 and the collet 132 can be made smaller. As a result, the axial dimension of the clamp mechanism 130 can be reduced.

The actuator 1 of the present embodiment includes a housing 40, a first rotor 20, a second rotor 30, a shaft member SF (screw shaft 52 and a shaft 62), a nut 51, and a spline outer cylinder 61. The first rotor 20 is rotatable with respect to the housing 40. The second rotor 30 is arranged radially outside the first rotor 20 and is rotatable with respect to the housing 40. The shaft member SF is arranged so as to penetrate the first rotor 20 in the axial direction of the rotating shaft AX of the first rotor 20, has a screw shaft 52 protruding from the first rotor 20 in one axial direction, and has a first rotor. The shaft 62 projecting from 20 to the other in the axial direction has a groove portion 62a along the axial direction. The nut 51 is arranged outside the lower side in the axial direction with respect to the first rotor 20, is screwed into the screw shaft 52, and rotates together with the first rotor 20 to move the shaft member SF in the axial direction of the rotating shaft AX. .. The spline outer cylinder 61 is arranged outside the upper side in the axial direction with respect to the first rotor 20, guides the shaft member SF in the axial direction along the groove 62a, and rotates together with the second rotor 30 to rotate the shaft member SF. Is rotated in the axial direction of the rotation shaft AX of the second rotor 30.

According to this configuration, the nut 51 and the spline outer cylinder 61 are arranged outside the rotation axis AX in the axial direction with respect to the first rotor 20, so that the first rotor 20 and the second rotor 30 are miniaturized in the radial direction. can do. As a result, the footprint can be reduced.

1 Actuator 10 Stator 20 1st rotor 30 2nd rotor 40 Housing 50 Ball screw 51 Nut 52 Screw shaft 52a Threaded part 52b Clamped part 56 Connecting part 60 Ball spline 61 Spline outer cylinder 62 Shaft 62a Groove 80 Arm part 101a, 102b Resolver stator 101b, 102a Resolver rotor 130 Clamp mechanism 132 Collet 132A Gripping part 132B Flange part 132a First tapered surface 132d Inner peripheral surface 134 Cylinder 136 Piston 136a Inclined surface (chuck part)
138 Cylinder tube 138g Gas supply path 156 Spring 160 First seal member 162 Second seal member 163 Gas supply unit 164 Compressed air AX Rotating shaft SF Shaft member MP Two-axis integrated motor ST fixing base

Claims (3)

Shaft member and
The collet through which the shaft member penetrates
A cylinder having a piston through which the shaft member penetrates, a cylinder tube for accommodating the piston, and an elastic member for urging the piston.
With
The piston, said elastic member by that contact with the peripheral surface of said collet, said chromatic Suruku lamp chuck portion for pressing the shaft member collet mechanism,
A drive unit capable of moving the shaft member in the axial direction and rotating the shaft member,
With
The clamp mechanism is
When the piston moves along the shaft member in the direction in which the elastic member is urged, the chuck portion comes into contact with the outer peripheral surface of the collet and presses the collet against the shaft member. When gas or liquid is supplied to the inside of the cylinder tube, the piston moves along the shaft member in a direction that opposes the urging by the elastic member, thereby pressing the collet against the shaft member by the chuck portion. It is configured to be released so that the collet separates from the shaft member.
Actuator. The outer peripheral surface is a tapered surface whose diameter decreases as it approaches the chuck portion.
The actuator according to claim 1, wherein the chuck portion is an inclined surface facing the outer peripheral surface. A housing for accommodating the clamp mechanism and the drive unit is provided.
The drive unit includes a first rotor that is rotatable with respect to the housing, a second rotor that is arranged radially outside the first rotor and is rotatable with respect to the housing, a nut, and a spline outer cylinder. Have,
The shaft member is arranged so as to penetrate the first rotor, has a screw portion in a first portion protruding from the first rotor in one axial direction, and from the first rotor to the other in the axial direction. The protruding second portion has a groove portion along the axial direction.
The nut is screwed into the threaded portion and rotates together with the first rotor to move the shaft member in the axial direction.
The spline outer cylinder guides the shaft member in the axial direction along the groove portion and rotates together with the second rotor to rotate the shaft member in the axial direction of the rotation shaft of the second rotor. The actuator according to claim 1 or 2.

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