JP2001258206A - Actuator with two-degree of freedom - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small-sized light-weight actuator with two-degree of freedom which has excellent response. SOLUTION: A rotational motor 10 and a linear motor 13 are coaxially arranged above and below the axial direction of an output shaft 5. Frames 3, 4 of fixing side components which are positioned outside the motors 10 and 13, respectively, are constituted integrally. Output shafts 5 for rotational movement and linear movement which are positioned inside the motors 10 and 13 are constituted integrally. In the rotational motor 10, a rotating type rolling bearing having a track trench in the circumferential direction is arranged between the fixing side components and rotating side components, and a linear type rolling bearing having a track trench in the axial direction is arranged between the rotating side components and the output shaft. In the linear motor 13, a linear type rolling bearing having a track trench in the axial direction is arranged between the fixing side components and the moving side components, and a rotation type rolling bearing having a track trench in the circumferential direction is arranged between the moving side components and the output shaft.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-degree-of-freedom actuator having an output shaft for performing rotation and linear movement used in a component mounting device for mounting an electronic component such as a semiconductor chip on an electronic circuit board. It is about.

[0002]

2. Description of the Related Art The structure of a conventional two-degree-of-freedom actuator is shown in FIGS. 6, 7, and 8 (Japanese Patent Laid-Open No. 5-82998) and FIG. 9 (Japanese Patent Laid-Open No. 6-303737). First, FIG. 6 (JP-A-5-8299)
8 (FIG. 4) will be described. The actuator F includes an upper rotary motor 106 and a lower cylindrical linear motor 1.
The output shaft 109 is a single component extending from above to below the actuator F. The rotary motor 106 is a permanent magnet synchronous servo motor, and includes a permanent magnet 107, a coil (stator) 1
08, rotation shaft 129, rotation angle sensor 110, case 10
6a and a bearing 106b. Rotary shaft 12
9 is supported by a bearing 106b mounted on a case 106a. The cylindrical linear motor 111 is a coil movable linear servomotor, and includes a yoke 112, a permanent magnet 113, a moving element 114, a displacement sensor 115, an output shaft 109, a case 111a, a stroke rotary bush 132, and a ball spline 131. You. The output shaft 109 is connected to the case 10 of the rotary motor 106.
6a and a case 111a of a cylindrical linear motor 111.
Is guided by a ball spline 131 attached to the lower end of the ball. The rotation shaft 12 of the rotary motor 106
9 is a case 111 of the cylindrical linear motor 111.
It is integrated with the upper part of a. The rotation and vertical movement of the output shaft 109 are performed as follows. First, when the rotary motor 106 operates to rotate the rotary shaft 129, the rotation is output via the ball spline 131 via the case 111 a of the cylindrical linear motor 111 connected to the lower end of the rotary shaft 129. Transmitted to shaft 109 and output shaft 109
Rotates while being axially supported by the two bearings 106 b and the stroke rotary bush 132. Next, when the cylindrical linear motor 111 operates, the output shaft 109 moves up and down while being guided by the stroke rotary bush 132 and the ball spline 131 as the mover 114 moves up and down. Second, FIG. 7 (FIG. 5 of JP-A-5-82998) will be described. The actuator G includes a rotary motor 233
And the cylindrical linear motor 234 are arranged on the outside and the inside, and the output shaft 235 is a single component extending from above to below the actuator G. The rotary motor 233 is a permanent magnet synchronous servo motor, and includes a permanent magnet 207, a coil (stator) 208, and a rotating shaft 234.
a, rotation angle sensor 210, case 233a, bearing 206
b. The rotating shaft 234a is supported by a bearing 206b mounted on the case 233a. The cylindrical linear motor 234 is a coil movable linear servomotor, and includes a yoke 212, a permanent magnet 213,
14, displacement sensor 215, output shaft 235, case 234
a, linear bush 237 and ball spline 2
36. The output shaft 235 is connected to the rotary motor 23
The linear bush 2 attached to the upper and lower ends of the case 234a of the cylindrical linear motor 234 also serving as the rotary shaft
37 and a ball spline 236. The rotation and vertical movement of the output shaft 235 are performed as follows. First, the rotary motor 233 is operated to rotate the rotary shaft 234.
When the output shaft 23 rotates through the output shaft 23 via a ball spline 236 attached to the lower end of the rotation shaft 234a.
5, the output shaft 235 is connected to two bearings 206b.
It is supported by and rotates. Next, the cylindrical linear motor 2
When the actuator 34 operates, the output shaft 235 moves up and down while being guided by the linear bushing 237 and the ball spline 236 in accordance with the vertical movement of the movable element 214. Third, FIG. 8 (FIG. 6 of JP-A-5-82998) will be described. The actuator H includes a rotary motor 338 and a cylindrical linear motor 33.
9 are arranged on the upper side and the lower side.
Reference numeral 2 denotes a single common component extending from above the actuator H to below. The rotary motor 338 is a permanent magnet type step motor, and has an exciting coil 340 and a permanent magnet 3.
41, magnetic pole teeth 342, rotor 344, rotor teeth 345,
Output shaft 352, rotation angle sensor 343, and case 33
8a. The output shaft 352 is connected to the upper and lower ends of the case 338 a by the stroke rotary bush 35.
3 and 354. The cylindrical linear motor 339 is a permanent magnet linear step motor, and includes an exciting coil 346, a permanent magnet 347, magnetic pole teeth 348, a moving element 350, moving element teeth 351, an output shaft 352, a displacement sensor 349, and a case 338a. Be composed. The output shaft 352 is guided by stroke rotary bushes 353 and 354 attached to upper and lower ends of a case 338a. The case 338a is provided with the rotary motor 33.
8 and the case of the cylindrical linear motor 339, and the rotor 344 and the mover 350 are coaxially arranged and integrated with the output shaft 352. The rotation and vertical movement of the output shaft 352 are performed as follows. First, when the rotary motor 338 operates and the rotor 344 rotates, the output shaft 352 is rotatably supported by the two stroke rotary bushes 353 and 354 with this rotation. Next, when the cylindrical linear motor 339 operates, the moving element 3
With the vertical movement of 50, the output shaft 352 moves up and down while being guided by the two stroke rotary bushes 353 and 354. Finally, FIG. 9 (JP-A-6-303737) will be described. The actuator I has a structure in which an upper cylindrical linear motor 413 and a lower rotary motor 410 are vertically coupled, and an output shaft 405 is a single component extending from above the actuator I to below. . The rotary motor 410 is a permanent magnet synchronous type step motor,
Stator 412, rotor 411, hollow shaft 406, case 4
04, and bearings 407 and 408. Hollow shaft 406 is provided with bearings 407, 4 attached to case 404.
08 supported. The cylindrical linear motor 413
Are a stator 414, a permanent magnet 417, a mover 415, an output shaft 405, a case 403, a bearing 416, a stroke rotary bush 418 (described as a linear bearing in the gazette),
And a ball spline 409 (described as a spline guide bearing in the gazette). The mover 415 is connected to the output shaft 405 via a bearing 416. The output shaft 405 is guided by a ball spline 409 mounted inside the hollow shaft 406 of the rotary motor 110 and a stroke rotary bush 418 mounted inside the case 403 of the cylindrical linear motor 413. The rotation and vertical movement of the output shaft 405 are performed as follows. First, when the rotary motor 410 operates to rotate the hollow shaft 406, the rotation is transmitted to the output shaft 410 via a ball spline mounted inside the hollow shaft 406, and the output shaft 410 has two bearings 407. , 408 while rotating. At this time, the moving element 415
Does not rotate due to the presence of the bearing 416. Next, when the cylindrical linear motor 413 operates, the output shaft 405 is guided by the stroke rotary bush 418 and the ball spline 419 to move up and down with the up and down movement of the mover 415.

[0003]

However, the conventional techniques have the following problems. First, the case of FIG. 6 will be described. When the rotary motor 106 rotates, the permanent magnet 107 to be rotated, the rotating shaft 129, the ball spline 131, and the output shaft 10
9 and the case 111 of the cylindrical linear motor 111
a, yoke 112, permanent magnet 113, and mover 11
4 also rotates, the inertia of the rotary motor 106 is large. Further, since the distance from the lower bearing 106b supporting the rotation of the rotary motor 106 to the lower end of the output shaft 109 is long, the bending rigidity, torsional rigidity,
Low axial rigidity. When the cylindrical linear motor 111 operates, the upper stroke rotary bush 132 of the two bearings that guide the linear motion does not have a restraining force in the circumferential direction. Low torsional rigidity. Second, the case of FIG. 7 will be described.
When the rotary motor 233 rotates, the permanent magnet 207 to be rotated, the rotating shaft 234a, the ball spline 2
Since the yoke 212, the permanent magnet 213, and the mover 214 of the cylindrical linear motor 234 also rotate in addition to the motor 36 and the output shaft 235, the inertia of the rotary motor 233 is large. When the cylindrical linear motor 234 operates, the upper linear rebush 237 of the two bearings that guide the linear motion does not have a restraining force in the circumferential direction. Low torsional rigidity. Third, FIG. 8 will be described. Rotary motor 338
When the rotor rotates, the rotor 344 to be rotated, the rotor teeth 345, the stroke rotary bushes 353 and 35
In addition to 4 and the output shaft 352, the mover 350 and mover teeth 351 of the cylindrical linear motor 339 also rotate, so that the inertia of the rotary motor 338 is large. Also,
Two stroke rotary bush 35 supporting rotation
3 and 354 have no binding force in the axial direction.
The torsional rigidity and the axial rigidity of 52 are small. When the cylindrical linear motor 339 operates, the rotor 344 and the rotor teeth 345 of the rotary motor 338 linearly move in addition to the mover 350, the mover teeth 351, and the output shaft 352 which should move linearly. Therefore, the inertia of the cylindrical linear motor 339 is large. Further, since the two stroke rotary bushes 353 and 354 for guiding the linear motion do not have a restraining force in the rotation direction, the axial rigidity and the torsional rigidity of the output shaft 352 are small. Finally, FIG. 9 will be described. Since the upper stroke rotary bush 418 that guides the linear motion has no restraining force in the rotation direction, the axial rigidity and the torsional rigidity of the output shaft 409 are small. As described above, the conventional two-degree-of-freedom actuator having the output shaft that performs the rotation operation and the linear movement operation has a large inertia during rotation and at the same time as the rotation, and the rigidity of the output shaft is low. As a result, the conventional two-degree-of-freedom actuator has a problem that response is low, mass is large, and volume is large. The present invention has been made to solve such a problem, and an object of the present invention is to provide a small-sized and lightweight two-degree-of-freedom actuator having high responsiveness.

[0004]

In order to solve the above-mentioned problems, the present invention provides a two-degree-of-freedom actuator having an output shaft for performing a rotating operation and a linear moving operation as follows.・ The rotation motor and the direct drive motor are arranged coaxially above and below in the axial direction of the output shaft. • Combine and integrate the frame of the fixed-side parts located outside the rotary motor and the linear motor, or make up one part. -The rotation motor and the rotation and translation output shafts located inside the translation motor are combined and integrated or formed as one part. In the rotating motor, a rotary type rolling bearing having a circumferential raceway groove is disposed between the fixed-side component and the rotary-side component, and a linear raceway having an axial raceway groove between the rotary-side component and the output shaft. A dynamic rolling bearing is arranged. -In a linear motion motor, a linear motion rolling bearing having an axial raceway groove is disposed between a fixed component and a movable component, and has a circumferential raceway groove between the movable component and the output shaft. Rotary rolling bearings are arranged. Since the present invention has such a configuration, the following effects can be obtained. First, the operation during rotation will be described. The rotating components are only the rotating components of the rotating motor, the direct-acting rolling bearings, and the output shaft, and the inertia during rotation is minimized. And, since the rotary support is performed by the rotary rolling bearing of the rotary motor and the rotary rolling bearing of the direct drive motor, they have an axial restraining force,
In addition, since it is located near the upper and lower ends of the actuator, the bending rigidity, torsional rigidity, and axial rigidity of the output shaft are increased. Next, the operation at the time of linear motion will be described. The linearly moving parts are only the moving side parts of the linear motor, the rotary rolling bearing and the output shaft, and the inertia during the linear movement is minimized. Since the linear motion guide is performed by the linear motion rolling bearing of the linear motion motor and the linear motion rolling bearing of the rotation motor, they have a restraining force in the rotational direction, and have a Since the output shaft is located near the end, the bending rigidity, axial rigidity, and torsional rigidity of the output shaft are increased.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a side sectional view showing a first embodiment of the present invention. The actuator A generally includes an upper linear motor 13 and a lower rotation motor 10.
Reference numeral 1 denotes a flat mounting base, to which a mounting plate 2 is fixed. A double cylindrical linear motor frame 3 composed of an outer cylinder 3a and an inner cylinder 3b is fixed above the mounting plate 2, and a cylindrical rotary motor frame below the mounting plate 2. 4 is fixed. Rotary motor 1
Reference numeral 0 denotes a rotation motor such as a step motor, and a stator 12 including an armature winding is mounted on the inner periphery of the rotation motor frame 4. Inside the rotary motor frame 4, deep groove ball bearings 7, 8 which are a kind of rotary rolling bearings are provided.
, The rotary hollow shaft 6 is attached, and a rotor 11 including a permanent magnet is fixed to the outer periphery of the rotary hollow shaft 6. The output shaft 5 arranged in the axial direction of the linear motor frame 3 and the rotary motor frame 4 is attached to the inside of the rotary hollow shaft 6 via a ball spline 9 which is a kind of a linear motion rolling bearing. I have. A ball spline groove 5 a that engages with a nut of the ball spline 9 is provided on the outer peripheral surface below the output shaft 5. The linear motor 13 is a linear motor such as a voice coil motor, and has a stator 14 mounted on the inner peripheral surface of the outer cylinder 3 a of the linear motor frame 3. A linear motion frame 18 is mounted on an upper portion of the outer cylinder 3a of the linear motor frame 3, and a linear guide rail 19b of a linear guide 19, which is a type of linear motion rolling bearing, is mounted on the inner peripheral surface of the linear motion frame 18. The head 20b of the linear encoder 20 is fixed. A cylindrical movable element 15 having a permanent magnet 17 mounted thereon is disposed between the stator 14 of the linear motor frame 3 and the inner cylinder 3b, and a slider 19a of a linear guide 19 and a linear A linear motion support 21 to which the slit 20a of the encoder 20 is attached is fixed. The slit 20a and the head 20b of the linear encoder 20 are fixed at positions facing each other with a certain gap. The moving element 15 is guided via a linear guide 19. A deep groove ball bearing 16, which is a kind of rotary rolling bearing, is mounted inside the mover 15, and the output shaft 5 is rotatably supported via the deep groove ball bearing 16. In addition, it is desirable to use one to six linear guides, and to arrange a plurality of linear guides at equal intervals in the circumferential direction. 2 configured in this way
In the degree-of-freedom actuator A, when the rotation motor 10 is first driven, the rotary hollow shaft 6 rotates integrally with the rotor 11, and the spline groove 5 a engages with the spline nut 9 fixed to the inner periphery of the rotary hollow shaft 6. And the output shaft 5 rotates integrally. However, since the mover 15 of the linear motor 13 is supported by the output shaft 5 via the bearing 16 and supported by the linear guide 19 via the linear motion frame 18 to restrict the rotation, Even when the shaft 5 rotates, the moving element 15 of the linear motor 13 does not rotate, so that the inertia of rotation is small. Next, when the linear motor 13 is driven in the upward direction, the moving element 15, the slider 19a of the linear guide 19, the linear support 21, the slit 20a of the position detection encoder 20, the bearing 16 and the output shaft 5 move upward. I do. However, the nuts of the rotor 11, the rotary hollow shaft 6, and the ball spline 9 of the rotary motor are
, And does not move in the vertical direction, so that the direct-acting inertia is small. The rotary rolling bearings 7 and 8 of the rotary motor 10 supporting the rotation of the actuator A and the rotary rolling bearing 16 of the linear motor 13 have an axial restraining force and are close to the upper and lower ends of the actuator A. Since the output shaft 5 is located at the place, the bending stiffness, torsional synthesis, and axial stiffness of the output shaft 5 increase. Similarly, the linear motion rolling bearing 19 of the linear motion motor 13 for guiding the linear motion of the actuator A and the linear motion rolling bearing 9 of the rotation motor 10 have a restraining force in the rotation direction, and Since it is located near the upper and lower ends, the bending rigidity of the output shaft 5,
Axial rigidity and torsional rigidity are increased. Therefore, in the present actuator A, since the inertia of the rotary motion part and the linear motion part is minimized and the rigidity of the output shaft 5 is increased, the responsiveness is improved, and the size and weight are reduced. Rotary rolling bearings are rolling bearings with a raceway in the circumferential direction, such as deep groove ball bearings, angular contact ball bearings, four-point contact ball bearings, cylindrical roller bearings, cross roller bearings, etc., and linear motion rolling bearings. Is a rolling bearing having a linear raceway groove such as a linear guide and a ball spline. In addition, the rotary motor 10
The arrangement of the direct drive type motor 13 may be upside down. As for the preload of the bearing, it is desirable to make the internal clearance negative, or to apply a slight preload by a fixed position preload or a constant pressure preload. FIG. 2 shows a second embodiment of the present invention.
FIG. 4 is a side sectional view showing an example of FIG. The actuator B in this embodiment is configured by changing the deep groove ball bearing 16 in FIG. 1 to a combined angular ball bearing 26. Thereby, the rigidity of the upper part of the output shaft 5 is further improved. The other configuration and operation are the same as those of the first embodiment, and the description is omitted. FIG. 3 is a side sectional view showing a third embodiment of the present invention. The actuator C in this embodiment is configured by changing the deep groove ball bearing 16 in the first embodiment of FIG. 1 to two deep groove ball bearings 36. Thereby, the rigidity of the upper part of the output shaft 5 is further improved. Further, by disposing the linear guide 19 and the linear encoder 20 on the side of the linear motor 13, the height of the actuator C can be reduced. Also in the case of the present embodiment, the two deep groove ball bearings 36 may be replaced by two angular ball bearings. The other configuration and operation are the same as those of the first embodiment, and the description is omitted. FIG. 4 is a side sectional view showing a fourth embodiment of the present invention. The actuator D in this embodiment is configured by replacing the linear guide 19 in FIG. 1 with a hollow ball spline 49 and disposing the linear encoder 20 on the center side of the actuator 40. Thus, while the linear motion rolling bearing 49 on the upper side of the actuator 40 is made into one component, the output shaft 5
The stiffness of the upper part is further improved. The other configuration and operation are the same as those of the first embodiment, and the description is omitted. FIG. 5 is a side sectional view showing a fifth embodiment of the present invention. The actuator E in this embodiment has a configuration in which the cylindrical linear motor 13 in FIG. 1 is replaced with a planar linear motor 53, and the linear guide 19 and the linear encoder 20 are lowered to the position of the planar linear motor 53 and mounted. It is. As a result, the overall length of the actuator 50 becomes shorter. The other configuration and operation are the same as those of the first embodiment, and the description is omitted.

[0006]

As described above, the present invention has the following effects. (1) Because the moving element of the linear motor does not rotate when the rotating motor rotates, and the rotating motor does not move up and down when the linear motor moves up and down. Motor inertia during rotation and linear motion is minimized. (2) Each bearing with a raceway groove receives a restraining force in the direction perpendicular to the raceway groove, and since each bearing is located near the upper and lower ends of the actuator, the rigidity of the output shaft improves. . Therefore, the responsiveness at the time of rotation and linear movement of the actuator is improved, and high-speed operation is possible. (3) The inertia of the motor during rotation and linear movement can be minimized, and the capacity of the rotary motor and the linear motor can be reduced. Thereby, the size and weight of the actuator can be reduced.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a two-degree-of-freedom actuator showing a first embodiment of the present invention.

FIG. 2 is a side sectional view of a two-degree-of-freedom actuator showing a second embodiment of the present invention.

FIG. 3 is a side sectional view of a two-degree-of-freedom actuator showing a third embodiment of the present invention.

FIG. 4 is a side sectional view of a two-degree-of-freedom actuator showing a fourth embodiment of the present invention.

FIG. 5 is a side sectional view of a two-degree-of-freedom actuator showing a fifth embodiment of the present invention.

FIG. 6 is a side sectional view of a two-degree-of-freedom actuator showing a first conventional example.

FIG. 7 is a side sectional view of a two-degree-of-freedom actuator showing a second conventional example.

FIG. 8 is a side sectional view of a two-degree-of-freedom actuator showing a third conventional example.

FIG. 9 is a side sectional view of a two-degree-of-freedom actuator showing a fourth conventional example.

[Explanation of symbols]

 Reference Signs List 1 mounting base, 2 mounting plate, 3 linear motor frame, 3a outer cylinder, 3b inner cylinder, 4 rotation type motor frame, 5 output shaft, 5a spline groove, 6 rotating hollow shaft, 7 deep groove ball bearing, 8 deep groove type Ball bearings, 9 ball splines, 10 rotary motors, 11 rotors, 12 stators, 13 linear motors, 14 stators, 15 movers, 16 deep groove ball bearings, 17 permanent magnets, 18 direct acting frame, 19 linear Guide, 19a Nut, 19b Rail, 20 Linear Encoder, 20a Slit, 20b Head, 21 Linear Motion Support, 26 Deep Groove Ball Bearing, 36 Combination Angular Contact Ball Bearing, 49 Ball Spline, 53 Planar Linear Motor

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5H607 AA00 AA12 BB10 BB11 BB14 CC01 DD01 DD02 DD04 DD16 DD17 EE18 FF12 GG08 HH01 5H633 BB08 BB10 GG02 GG17 HH03 JA08 JA10

Claims (1)

[Claims] 1. A two-degree-of-freedom actuator having an output shaft that performs rotation and linear motion, wherein a rotation motor and a linear motion motor are arranged coaxially above and below in the axial direction of the output shaft. Along with integrally configuring the frame of each fixed-side component located outside the linear motor, the rotary motor and the rotary and linear output shafts located inside the linear motor are integrally configured, Further, the rotating motor includes a rotary rolling bearing having a circumferential raceway groove between the fixed part and the rotation part, and an axial raceway groove between the rotation part and the output shaft. A linear motion rolling bearing having a linear motion rolling bearing having an axial raceway groove between a fixed component and a moving component is provided, and the linear motor has an output and a moving component. axis 2. A two-degree-of-freedom actuator having a rotary rolling bearing having a circumferential raceway groove disposed between the two rolling elements.