JP2016156407A - Rotating shaft driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotating shaft driving device incorporating a compact assist mechanism incorporating a permanent magnet and having excellent versatility.SOLUTION: An assist mechanism (10) includes an annular first supporting member (11) fixed to a shaft supporting mechanism (3) and including a plurality of first permanent magnets (13), and an annular second supporting member (12) connected to a rotating shaft (2a) in a fixed state and including a plurality of second permanent magnets (14). The first permanent magnets (13) and the second permanent magnets (14) are intermittently arranged and held in circumferential directions so that their directions of magnetic field are faced to a direction in parallel with a shaft center (A) of the rotating shaft (2a), and disposed so as to be able to be opposed to each other in a close state in the direction in parallel with the shaft center. When the rotating shaft (2a) is rotated by a set angle to at least one of a forward direction and a backward direction by rotating driving means (5), an assist torque for reducing a load of the rotating driving means (5) is generated by magnetic force of the first permanent magnets (13) and the second permanent magnets (14).SELECTED DRAWING: Figure 1

Description

  The present invention relates to a rotary shaft drive device, and more particularly to a device provided with an assist mechanism that generates an assist torque that reduces the load on a rotary shaft drive means by the magnetic force of a permanent magnet.

  The rotating shaft is rotatably supported by the shaft support mechanism, one end member of the driven member such as an arm member is connected to the rotating shaft, and the rotating shaft is rotated by the rotation driving means so that the driven member is rotated around the rotating shaft. Rotating shaft driving devices that swing and drive are incorporated in various mechanical devices. When the moment of inertia of the driven member increases, the rotating shaft driving device is usually enlarged, but even if a large rotating shaft driving device is adopted, it is difficult to increase the rotational drive speed. In particular, when a load caused by the weight of the driven member and the attached member attached thereto acts, the rotating shaft driving device needs to rotate the rotating shaft against the load caused by the weight. Therefore, a technique for incorporating assist means for reducing a part of the load of the rotary shaft drive device is known in order to increase the speed and / or size of the rotary shaft drive device.

  In the indexer device described in Patent Document 1, a substantially elliptical cam plate is attached to a rotating shaft that rotates a table unit, and a roller at the tip of an output rod of a gas spring provided in the shaft support mechanism is attached to the outer peripheral surface of the cam plate. When the table unit swings upward from the lowest position, an assist torque is generated by the gas spring.

In the articulated robot disclosed in Patent Document 2, one end of a gas spring is connected to a rotating shaft that rotates a lower end portion of a lower arm (driven member), and assists with the gas spring when the lower arm is driven to swing upward. Generate torque.
The robot described in FIGS. 1 and 2 of Patent Document 3 is configured to generate assist torque by a spring unit.

JP 2013-32827 A JP 2014-195849 A Japanese Patent No. 3614383

  In the assist mechanism that generates assist torque by the gas spring, the gas spring has a large overall length, and the gas spring cannot be incorporated into the rotating shaft driving device, so that the rotating shaft driving device is enlarged. In a multi-joint robot or the like, a plurality of arm members are provided. However, since the rotating shaft driving device is enlarged, for example, only a part of the rotating shaft driving unit such as a rotating shaft driving unit that rotationally drives the lower arm. Only the assist mechanism can be used. The same applies to the assist mechanism including the spring unit.

  An object of the present invention is to provide a rotary shaft drive device incorporating a small and versatile assist mechanism utilizing a permanent magnet.

  The rotary shaft drive device of the present invention (Claim 1) includes a rotary shaft, a shaft support mechanism that rotatably supports the rotary shaft, and a rotary drive means that can rotationally drive the rotary shaft in the forward direction and the reverse direction. And a driven member that is driven to swing around the rotation shaft by the rotation shaft. An annular ring fixed to the shaft support mechanism and disposed on the outer peripheral side of the rotation shaft. A first support member, an annular second support member fixedly connected to the rotation shaft and disposed on the outer peripheral side of the rotation shaft, and intermittently arranged in the circumferential direction on the first support member. In addition, a plurality of first permanent magnets whose magnetic field directions are parallel to the axis of the rotary shaft, and held intermittently in the circumferential direction on the second support member, and the magnetic field direction is parallel to the axis. An assist mechanism comprising a plurality of second permanent magnets oriented in a direction The plurality of first permanent magnets and the plurality of second permanent magnets are disposed so as to be able to face each other in an approaching state in a direction parallel to the shaft center, and the assist mechanism previously rotates the rotation shaft by the rotation driving means. When the set rotation position is rotated by a set angle of at least one of the normal rotation direction and the reverse rotation direction from the set rotation position, the load on the rotation driving means is reduced by the magnetic force of the plurality of first permanent magnets and the plurality of second permanent magnets. It is characterized by being configured to generate assist torque.

  According to a second aspect of the present invention, in the rotary shaft drive device according to the first aspect of the invention, in the plurality of first and second permanent magnets, the direction of the magnetic field of each pair of permanent magnets adjacent in the circumferential direction is set to be opposite. It is characterized by.

  According to a third aspect of the present invention, in the rotary shaft drive device according to the first or second aspect of the invention, the first support member is made of a magnetic material first annular substrate and a non-magnetic material fixed to the first annular substrate. An annular first magnet holding plate, and the second support member includes a second annular substrate made of a magnetic material, and an annular second magnet holding plate made of a non-magnetic material fixed to the second annular substrate. An annular second magnet holding plate that is adjacent to the first magnet holding plate with a minute gap therebetween, and a plurality of first magnets are accommodated intermittently in the circumferential direction on the first magnet holding plate. A plurality of first permanent magnets are accommodated in the plurality of first magnet accommodation holes, respectively, and a plurality of second magnet accommodation holes are intermittently formed in the circumferential direction in the second magnet holding plate. A plurality of second permanent magnets are accommodated in the plurality of second magnet accommodation holes, respectively, and a second magnet holding hole is accommodated in each of the first magnet accommodation holes. A bottom wall having a thickness of 5 mm or less that closes the plate side is formed, and a bottom wall having a thickness of 5 mm or less that closes the first magnet holding plate side is formed in each second magnet receiving hole. .

  According to a fourth aspect of the present invention, in the rotary shaft drive device according to the first or second aspect of the invention, the plurality of first and second permanent magnets are four permanent magnets respectively disposed at four equal positions in the circumferential direction. Each of the first and second permanent magnets is characterized by being formed in an arc shape having an opening angle of 50 to 70 ° with respect to the axis of the rotating shaft.

  According to a fifth aspect of the present invention, in the rotary shaft drive device according to the first or second aspect of the invention, the plurality of first and second permanent magnets are six permanent magnets arranged at six equal positions in the circumferential direction, respectively. Each of the first and second permanent magnets is characterized by being formed in an arc shape having an opening angle of 40 to 45 ° with respect to the axis of the rotating shaft.

  According to a sixth aspect of the present invention, in the rotary shaft drive device according to the first or second aspect of the invention, the plurality of first and second permanent magnets are respectively disposed at two of the three equal positions in the circumferential direction. There are two permanent magnets, and each of the first and second permanent magnets is characterized by being formed in an arc shape with an opening angle of 80 to 100 ° with respect to the axis of the rotating shaft.

  According to a seventh aspect of the present invention, in the rotary shaft drive device according to the sixth aspect of the present invention, a first portion made of a magnetic material is provided in a portion of the first magnet holding plate that faces the second permanent magnet when the rotary shaft rotates. A magnetic path forming member is incorporated, and a second magnetic path forming member made of a magnetic material is incorporated in a portion of the second magnet holding plate that faces the first permanent magnet when the rotating shaft rotates. It is characterized by.

  According to an eighth aspect of the present invention, there is provided the rotary shaft drive device according to the first or second aspect, wherein the rotary shaft is a rotary shaft mounted on a joint portion of the robot, and the driven member is an arm member of the robot. It is characterized by.

  According to a ninth aspect of the present invention, in the invention of the first or second aspect, the rotary shaft is a pivot shaft of an indexer device, and the driven member is a table unit of the indexer device. .

  According to the first aspect of the present invention, since the configuration described in the problem solving means column is provided, the rotational shaft is set to a set rotational position (for example, the positional energy in the rotational direction of the driven member and the workpiece supported thereby is minimized. At the home position rotation position), the plurality of first permanent magnets and the plurality of second permanent magnets face each other, and the magnetic field directions of the plurality of first permanent magnets and the magnetic fields of the plurality of second permanent magnets It is assumed that the directions are set so as to face each other (reverse direction). When the rotary shaft is rotated in at least one of the normal rotation direction and the reverse rotation direction from the set rotation position, the driven member is driven to swing upward by the rotation shaft, and the load on the rotation driving means increases. At this time, the assist mechanism generates the assist torque that reduces the load of the rotation driving means by the magnetic force (attraction force and / or repulsive force) of the plurality of first permanent magnets and the plurality of second permanent magnets. The size of the means can be reduced, and the rotational operation of the rotary shaft can be speeded up.

Since the assist mechanism for generating the assist torque with the plurality of first and second permanent magnets can be configured in a small size, the assist mechanism including the plurality of first and second permanent magnets can be used as the rotating shaft of the rotating shaft drive device. It can be incorporated in the peripheral part on the outer peripheral side. Therefore, it is excellent in versatility, for example, by being able to be adopted in a rotation shaft driving device of each of a plurality of joint portions of a multi-joint robot.
The set rotation position is not limited to the home position rotation position, and can be set to a desired rotation position.

  According to the invention of claim 2, in the plurality of first and second permanent magnets, the direction of the magnetic field of each pair of permanent magnets adjacent to each other in the circumferential direction is set to be opposite. Therefore, the first and second permanent magnets The assist torque can be generated by the suction force and the repulsive force.

According to the invention of claim 3, the first support member is composed of the first annular substrate made of magnetic material and the first magnet holding plate made of nonmagnetic material, and the second support member is made of the second annular member made of magnetic material. Consists of a substrate and a second magnet holding plate made of a non-magnetic material. A plurality of first permanent magnets are housed in a plurality of first magnet housing holes formed in the first magnet holding plate and formed on a second magnet holding plate. Since the plurality of second permanent magnets are accommodated in the plurality of second magnet accommodation holes, a magnetic path advantageous for generating assist torque can be formed.
Then, a bottom wall having a thickness of 5 mm or less that covers the second magnet holding plate side is formed in each first magnet housing hole, and a thickness of 5 mm or less that plugs the first magnet holding plate side in each second magnet housing hole. Since the bottom wall is formed, it is possible to prevent the magnetic force acting between the first and second permanent magnets from being weakened while preventing the first and second permanent magnets from adsorbing in close contact.

According to the fourth aspect of the present invention, the assist torque can be generated until the rotating shaft rotates about 90 ° in the forward rotation direction and the reverse rotation direction from the set rotation position.
According to the fifth aspect of the present invention, the assist torque can be generated until the rotation shaft rotates about 45 ° in the forward rotation direction and the reverse rotation direction from the set rotation position.

According to the sixth aspect of the present invention, the assist torque can be generated until the rotating shaft rotates about 120 ° in the forward rotation direction or the reverse rotation direction from the set rotation position.
According to the seventh aspect of the present invention, a closed loop magnetic path can be reliably formed when the assist torque is generated.

According to the eighth aspect of the present invention, the assist torque can be generated when the rotation shaft of the joint portion of the robot is rotationally driven by the rotational driving means to swing the arm member (driven member).
According to the ninth aspect of the present invention, the assist torque can be generated when the table unit of the indexer device is swung upward from the lowest position.

It is a front view of the indexer apparatus which concerns on Example 1 of this invention. It is a longitudinal cross-sectional view of the peripheral part of the rotation drive mechanism of an indexer apparatus. It is a perspective view of an assist mechanism. It is a longitudinal cross-sectional view of an assist mechanism. It is the C section enlarged view of FIG. It is the VI-VI sectional view taken on the line of FIG. It is the VII-VII sectional view taken on the line of FIG. It is explanatory drawing explaining the state of the magnetic field at the time of a home position rotation position. It is explanatory drawing explaining the magnetic path at the time of assist torque generation | occurrence | production. It is explanatory drawing explaining a magnetic path at the time of an assist end state. FIG. 6 is a front view of a main part of an articulated robot according to a second embodiment. FIG. 9 is a view corresponding to FIG. 7 of the first assist mechanism of Embodiment 2. FIG. 9 is a view corresponding to FIG. 8 of the first assist mechanism of Embodiment 2. FIG. 9 is a view corresponding to FIG. 7 of a second assist mechanism of Embodiment 2. FIG. 9 is a view corresponding to FIG. 8 of a second assist mechanism of Embodiment 2.

  EMBODIMENT OF THE INVENTION The form for implementing this invention is demonstrated based on an Example.

  The present embodiment is an example in which a rotary shaft driving device including an assist mechanism unique to the present application is applied to an indexer device that detachably mounts a workpiece to be machined by a machine tool. In the following description, the vertical and horizontal directions in FIG. 1 are assumed to be vertical and horizontal directions.

  As shown in FIG. 1, the indexer device 1 includes a table unit 2, a turntable 3 mounted on the table unit 2 so as to be rotatable, and a pair of left and right rotating shafts (pivot shafts) 2a fixed to the table unit 2. , 2b, a left shaft support mechanism 3 that rotatably supports the rotary shaft 2a, a right shaft support mechanism 4 that rotatably supports the rotary shaft 2b, and a horizontal rotation axis A between the table unit 2 and the rotary shafts 2a and 2b. A rotation drive mechanism 5 having an electric motor 5a that swings around (rotates) and an assist mechanism 10 that generates assist torque when the table unit 2 is swung upward from its lowest position are provided.

  Here, the table unit 2 corresponds to a “driven member”, and the table unit 2, the rotation shafts 2 a and 2 b, the left and right shaft support mechanisms 3 and 4, the rotation drive mechanism 5, and the assist mechanism 10. This corresponds to the “rotary shaft drive device” of the present invention.

  As shown in FIGS. 1 and 2, the rotation drive mechanism 5 is provided on the right shaft support mechanism 4, and a driving force is input from the rotation drive mechanism 5 to the rotation shaft 2 b to rotate the table unit 2. Is done. The rotational drive mechanism 5 includes a worm wheel 5b fixed to the rotary shaft 2b, a vertical worm gear 5c meshed with the worm wheel 5b, and an electric servo motor 5a capable of rotationally driving the worm gear 5c. ing.

  The table main body 2c of the table unit 2 is provided with a turntable 3 that can turn around a turning axis B in FIG. 1 and a rotation drive mechanism (not shown) thereof, and a work W can be attached to and detached from the turntable 3. The workpiece W is mounted and machined.

  Here, the table unit 2 is integrally connected to the right end portion of the rotating shaft 2a and integrally extends to the left arm portion 2d extending a predetermined length downward perpendicular to the axis A of the rotating shaft 2a and the left end portion of the rotating shaft 2b. And a table main body 2c, and the left and right end portions of the table main body 2c are connected to the left and right arm portions 2d and 2e, respectively. It is integrally connected to the lower end. As shown in FIG. 1, the state where the table main body 2c is positioned in the horizontal position at the lowest position is the home position of the table unit 2. At this home position, the rotation shafts 2a and 2b are also at the home position rotation position. In the present embodiment, the home position rotation position of the rotary shafts 2a and 2b corresponds to a preset “set rotation position”.

  As shown in FIGS. 1 and 3 to 5, the assist mechanism 10 is incorporated so as to apply assist torque to the left rotation shaft 2 a. The assist mechanism 10 includes an annular first support member 11 disposed on the outer peripheral side of the rotating shaft 2a, an annular second support member 12 disposed on the outer peripheral side of the rotating shaft 2a, and a first support member. 11 (four in the present embodiment) first permanent magnets 13 that are intermittently arranged and held in the circumferential direction, and a plurality (fourth embodiment) that are held intermittently in the circumferential direction on the second support member 12. Then, four) second permanent magnets 14 are provided.

  The first support member 11 is a first annular substrate 11a made of a magnetic material (for example, steel) parallel to a surface orthogonal to the axis A of the rotation shaft 2a, and is a vertical wall member 3a (stationary member) of the shaft support mechanism 3. ) And a non-magnetic material fixed to the left end surface of the first annular substrate 11a with a plurality of bolts and parallel to the first annular substrate 11a. And an annular first magnet holding plate 11b made of (for example, austenitic stainless steel).

The second support member 12 is an annular second annular substrate 12a made of a magnetic material parallel to a plane orthogonal to the axis A of the rotation shaft 2a, and is fixed by being externally fitted to the rotation shaft 2a. And a second magnet holding plate 12b made of a non-magnetic material, which is fixed to the right end surface of 12a and faces the first magnet holding plate 11b with a minute gap 15 therebetween.
The second magnet holding plate 12b is composed of a cylindrical portion 12c fitted on the rotary shaft 2a and an annular plate portion 12d integrated with the cylindrical portion 12c. The cylindrical portion 12c is an inner part of the first magnet holding plate 11b. A thrust bearing 16 is interposed between the annular plate portion 12d and the first annular substrate 11a on the outer peripheral side of the cylindrical portion 12c. In addition, shaft holes 11c, 12e, and 12f for inserting the rotation shaft 2a are formed in the first annular substrate 11a, the second annular substrate 12a, and the cylindrical portion 12c.

  A partial conical surface 17 with a diameter decreasing toward the right is formed on the inner peripheral portion of the left side of the cylindrical portion 12c. The annular wedge member 18 is inserted between the outer peripheral surface of the rotating shaft 2a and the partial conical surface 17. Then, the annular wedge member 18 is fixed to the cylindrical portion 12c with a plurality of bolts 18a, whereby the second annular substrate 12a and the second magnet holding plate 12b are fixed to the rotating shaft 2a so as not to be relatively rotatable.

  As shown in FIGS. 4 to 7, a plurality of (four in this embodiment) first magnet accommodation holes 19 are intermittently formed in the circumferential direction in the first magnet holding plate 11b, and the plurality of first magnets are accommodated. The plurality of first permanent magnets 13 are accommodated in the holes 19, respectively, and the direction of the magnetic field of the plurality of first permanent magnets 13 is directed in a direction parallel to the axis A of the rotating shaft 2 a. The magnetic poles shown in FIG. 6 indicate the magnetic poles at the left end of the first permanent magnet 13 when the rotary shaft 2a is at the set rotational position. In the plurality of first permanent magnets 13, the direction of the magnetic field of each pair of permanent magnets adjacent in the circumferential direction is set to be opposite. The plurality of first permanent magnets 13 are four powerful permanent magnets (for example, neodymium magnets) disposed at positions equally divided in the circumferential direction, and the first permanent magnets 13 are predetermined in the axial direction of the rotating shaft. And having a radial width of about twice the thickness, and an open angle with respect to the axis A is 50 ° to 70 ° (60 ° in this embodiment). Yes.

The left end surface of the first magnet holding plate 11b and the right end surface of the annular plate portion 12d of the second magnet holding plate 12b are parallel to the surface orthogonal to the axis A of the rotating shaft 2a, and the left end surface of the first magnet holding plate 11b. And a right end surface of the annular plate portion 12d is formed with a minute gap 15 (0.1 mm to 0.2 mm in this embodiment). This is to prevent wear due to contact.
Each first magnet receiving hole 19 is formed with a bottom wall 19a having a thickness of 5 mm or less (preferably a thickness of 2 mm or less, in this embodiment 0.5 mm) that closes the second magnet holding plate 12b side. ing. The bottom wall 19a is for preventing the first permanent magnet 13 and the second permanent magnet 14 from being firmly adsorbed. However, although the bottom wall 19a may be omitted, in this case, it is desirable to fix the first permanent magnet 13 to the first annular substrate 11a with a bolt.

  As shown in FIGS. 4 to 7, a plurality (four in this embodiment) of second magnet housing holes 20 are formed intermittently in the circumferential direction in the annular plate portion 12d of the second magnet holding plate 12b. The plurality of second permanent magnets 14 are respectively accommodated in the second magnet accommodation holes 20, and the direction of the magnetic field of the plurality of second permanent magnets 14 is directed parallel to the axis A of the rotation shaft 2 a. The magnetic poles shown in FIG. 7 indicate the magnetic poles at the right end of the second permanent magnet 14 when the rotary shaft 2a is at the set rotational position. In the plurality of second permanent magnets 14, the direction of the magnetic field of each pair of permanent magnets adjacent in the circumferential direction is set to be opposite. The plurality of second permanent magnets 14 are four strong permanent magnets arranged at four equal positions in the circumferential direction, and each second permanent magnet 14 has a predetermined thickness in the direction of the axis A of the rotating shaft 2a. And has a radial width that is approximately twice the thickness thereof, and is formed in an arc shape with an opening angle of 50 to 70 ° (60 ° in this embodiment) with respect to the axis A of the rotating shaft 2a. Yes. In the present embodiment, the first and second permanent magnets 13 and 14 are of the same size and shape.

  A bottom wall 20a having a thickness of 5 mm or less (preferably a thickness of 2 mm or less, and a thickness of 0.5 mm in this embodiment) is formed in each second magnet accommodation hole 20 to close the first magnet holding plate 11b side. ing. The bottom wall 20a is for preventing the first permanent magnet 13 and the second permanent magnet 14 from being firmly adsorbed. However, the bottom wall 20a may be omitted, but in this case, it is desirable to fix the second permanent magnet 14 to the second annular substrate 12a with a bolt.

  When the rotating shaft 2a rotates from the set rotation position, the plurality of second permanent magnets 14 rotate relative to the plurality of stationary first permanent magnets 13, but the plurality of first permanent magnets 13 and the plurality of first permanent magnets 13 The 2nd permanent magnet 14 is arrange | positioned so that it can oppose in the approach state in the parallel direction with the axial center A of the rotating shaft 2a.

  In the indexer device 1, the maximum rotation angle of the rotation shafts 2a and 2b in the forward rotation direction and the reverse rotation direction is an angle of 90 ° or less. Therefore, the assist mechanism 10 rotates the rotation shafts 2a and 2b from the home position rotation position (set rotation position) to at least one of the normal rotation direction and the reverse rotation direction by the rotation driving mechanism 5 (90 ° in this embodiment). In this case, an assist torque that reduces the load on the rotary drive mechanism 5 is generated by the magnetic force of the plurality of first permanent magnets 13 and the plurality of second permanent magnets 14.

  6 and 7 show the first and second permanent magnets 13 and 14 when the rotary shafts 2a and 2b are at the set rotational positions corresponding to the home positions. One permanent magnet 13 and a plurality of second permanent magnets 14 face each other. The rotational direction positions (phase positions) of the first and second permanent magnets 13 and 14 at the set rotational position are not limited to those shown in FIGS. For example, it may be a position rotated (moved) by 45 ° in the clockwise direction or the counterclockwise direction from the rotational direction position shown in FIG.

  Next, operations and effects of the rotary shaft driving device including the assist mechanism 10 described above will be described. FIGS. 8 to 10 are explanatory views in which the views of the first and second permanent magnets 13 and 14 of the assist mechanism 10 viewed from the outer peripheral surface are expanded by 360 °, and are taken along line EE in FIG. One line is up to the line.

FIG. 8 shows a state in which the table unit 2 is at the home position and the rotation shafts 2a and 2b are at the set rotation position. Since the table unit 2, the turntable 3, and the weight of the workpiece W act on the table unit 2, the table unit 2 is stable at the home position.
In this state, the direction of the magnetic field of each pair of the first and second permanent magnets 13 and 14 positioned in the opposing relationship is opposite, so that a closed loop magnetic path is not formed and no assist torque is generated. .

  Next, as shown in FIG. 9, when the rotation driving mechanism 5 starts to rotate the rotating shafts 2 a and 2 b in, for example, the normal rotation direction (the direction of arrow R in FIG. 9), a plurality of first permanent magnets 13 are provided. The second permanent magnet 14 relatively rotates and a closed loop magnetic path as shown in the figure is formed, so that the attraction acts between the plurality of first permanent magnets 13 and the plurality of second permanent magnets 14. The assist torque T is generated by the force and the repulsive force.

  That is, an attractive force acts on the first and second permanent magnets 13a, 14d; 13b, 14a; 13c, 14b; 13d, 14c of each group, and the first and second permanent magnets 13a, 14a; , 14b; 13c, 14c; 13d, 14d has a repulsive force. As a result, assist torque T that reduces the load on the rotary drive mechanism 5 and that is indicated by an arrow T in FIG. 9 is generated. The assist torque T acts while the rotary shafts 2a and 2b rotate by 90 °, and the magnitude of the assist torque T depends on the strength of the magnetic field generated by the first and second permanent magnets 13 and 14.

  In the case of the present embodiment, when the rotation angle of the rotary shaft 2a increases, the repulsive force between the first and second permanent magnets 13 and 14 decreases, while the attractive force between the first and second permanent magnets 13 and 14 decreases. Although it increases, the increase in the attractive force is greater than the decrease in the repulsive force, and therefore it is estimated that the assist torque increases as the rotation angle of the rotary shaft 2a increases.

FIG. 10 shows a state in which the rotating shafts 2a and 2b are rotated by 90 °. A closed loop magnetic path as shown in the figure is formed, and no assist torque that further rotates the rotating shafts 2a and 2b is generated. However, a holding force that holds the rotary shafts 2a and 2b in that position is generated.
In the above description, the rotating shafts 2a and 2b are rotated in the forward rotation direction, for example. However, the same applies to the case where the rotating shafts 2a and 2b are rotated in the reverse rotation direction opposite to the above.

As described above, when the table unit 2 is driven to swing upward, the assist mechanism 10 can generate an assist torque that reduces the load on the rotation drive mechanism 5, so that the electric servo motor of the rotation drive mechanism 5 can be generated. The size of 5a can be reduced to save power consumption, and the speed of the swing operation of the table unit 2 can be increased. In addition, since the assist mechanism 10 does not require a member that protrudes greatly to the outside of the left shaft support mechanism 3 and can be configured in a small size, the assist mechanism 10 can be incorporated into the left shaft support mechanism 3 in a compact manner.

  In the present embodiment, the assist mechanism 10 that generates assist torque while rotating the rotary shafts 2a and 2b by 90 ° is employed. However, the number and size of the plurality of first and second permanent magnets 13 and 14 can be appropriately set. For example, when the rotation shafts 2a and 2b are rotated at a desired angle between 0 ° and 180 °, for example, an assist torque capable of reducing the load of the rotation driving means can be generated. It is excellent and can be applied to various rotary shaft drive devices that swing the driven member around the rotary shaft (rotary drive, rotational drive) by the rotary shaft that is rotationally driven by the rotational drive means. Excellent.

  The first support member 11 is composed of a first annular substrate 11a made of a magnetic material and a first magnet holding plate 11b made of a nonmagnetic material, and the second support member 12 is not made of a second annular substrate 12a made of a magnetic material. A plurality of first permanent magnets 13 are accommodated in a plurality of first magnet accommodation holes 19 formed in the first magnet holding plate 11b, and the second magnet holding plate 12b. Since the plurality of second permanent magnets 14 are accommodated in the plurality of second magnet accommodation holes 20 formed in this manner, a magnetic path that is advantageous for generating assist torque can be formed.

  Moreover, since the bottom wall 19a for closing the second magnet holding plate 12b side is formed in each first magnet receiving hole 19, and the bottom wall 20a for closing the first magnet holding plate 11b side is formed in each second magnet holding hole 20, While preventing the first and second permanent magnets 13 and 14 from adsorbing in close contact, the magnetic path resistance between the first and second permanent magnets 13 and 14 can be suppressed from increasing.

  The second embodiment is an example in which the present invention is applied to a rotary shaft driving device that rotationally drives a rotary shaft of a joint portion of an articulated robot 30 (multi-joint manipulator), and will be described with reference to FIGS.

  As shown in FIG. 11, the articulated robot 30 includes a base 31, a swivel base 32 that is mounted on the base 31 so as to be rotatable about a vertical axis, and a pivotal support plate portion of the swivel base 32. A lower arm 34 supported by the first joint portion 33 at 32a, an upper arm 36 supported by the upper end portion of the lower arm 34 via the second joint portion 35, and a distal end side of the upper arm 36; The equipped hand rotation mechanism and hand mechanism (not shown), the turntable drive mechanism (not shown) capable of rotating the turntable 32, and the first joint portion 33 are provided to swing the lower arm 34. A first rotation drive mechanism including a first servo motor 37, a first assist mechanism 40 provided in the first joint portion 33, and a second servo provided in the second joint portion 35 to swing and drive the upper arm 36. A second rotational drive mechanism including a motor 38; And a second assist mechanism 50 that is provided on second joint portion 35.

  The first servo motor 37 is fixed to the pivotal support plate portion 32a and can rotate the first rotating shaft 33a. The first rotary shaft 33a is rotatably supported by a shaft support mechanism including a pivotal support plate portion 32a, the lower end portion of the lower arm 34 is fixed to the first rotary shaft 33a, and the lower arm 34 is centered on the first rotary shaft 33a. Is driven to swing. The second servo motor 38 is fixed to the pivot plate 34a at the upper end portion of the lower arm 34, and can rotate the second rotating shaft 35a. The second rotation shaft 35a is rotatably supported by a shaft support mechanism including a pivotal support plate portion 34a, the base end portion of the upper arm 36 is fixed to the second rotation shaft 35a, and the upper arm 36 attaches the second rotation shaft 35a to the second rotation shaft 35a. It is driven to swing around the center.

  As shown in FIGS. 11 to 13, the first assist mechanism 40 has the lower arm 34 set upward from a predetermined home position (for example, a position where the lower arm 34 is tilted to the maximum) upward (in the present embodiment, about 120 °). ) When swinging, that is, the first rotation shaft 33a is set to a set angle (in the present embodiment, about 120 in the forward rotation direction (the direction of arrow F in FIGS. 12 and 13), for example, from a preset set rotation position). °) When rotating, assist torque that reduces the load on the first servomotor 37 is generated.

  The first assist mechanism 40 is the same as the assist mechanism 10 of the first embodiment except for the size and number of the first and second permanent magnets 42 and 44 and the size and number of the first and second magnet housing holes 45 and 46. Since it is the same structure, it demonstrates easily. The first assist mechanism 40 includes a first support member 41 fixed to the pivot support plate portion 32a, two first permanent magnets 42 held by the first support member 41, a first rotating shaft 33a, and a lower arm. 34, a second support member 43 fixed to the lower end portion of 34, and two second permanent magnets 44 held by the second support member 43.

  The first support member 41 includes a first annular substrate 41a made of a magnetic material and a first magnet holding plate 41b made of a nonmagnetic material fixed to the first annular substrate 41a. The first magnet holding plate 41b is formed with two first magnet housing holes 45a, and the two first permanent magnets 42 are housed in the first magnet housing holes 45a, respectively. The two first permanent magnets 42a and 42b are arranged at two positions of the circumferentially equally divided position, and the opening angle of the first permanent magnet 42 with respect to the axis G of the rotating shaft 33a is 80 ° to 100 ° (this embodiment) In the example, it is 100 °).

  One end of the first permanent magnet 42a and one end of the first permanent magnet 42b are spaced apart by, for example, 20 ° in the circumferential direction, and the other end of the first permanent magnet 42a to the other end of the first permanent magnet 42b are spaced, for example, 140 ° Separated. The directions of the magnetic fields of the two first permanent magnets 42a and 42b are set in reverse. In addition, the bottom wall similar to the bottom wall 19a of Example 1 is formed in the 1st magnet accommodation hole 45a. However, the bottom wall may be omitted.

  A first magnetic path forming member 42m made of a magnetic material is incorporated in a portion of the first magnet holding plate 41b that faces the second permanent magnet 44 when the first rotating shaft 33a rotates. The first magnetic path forming member 42m is an arc-shaped holding hole 45b formed in a penetrating manner in the first magnet holding plate 41b, and is fitted and held in a holding hole 45b having the same shape as the first magnet housing hole 45a. Has been. The first magnetic path forming member 42m is for forming a closed loop magnetic path in cooperation with the second permanent magnet 44b when the first rotating shaft 33a rotates.

  The second support member 43 includes a second annular substrate 43a made of a magnetic material, and a second magnet holding plate 43b made of a nonmagnetic material fixed to the second annular substrate 43a. The second annular substrate 43a is fixed to the first rotating shaft 33a via the second magnet holding plate 43b. Two second magnet accommodation holes 46 are formed in the second magnet holding plate 43 b, and the two second permanent magnets 44 are accommodated in the second magnet accommodation holes 46, respectively. The two second permanent magnets 44a and 44b are disposed at two positions of the circumference equally divided into three positions, and the opening angle of the second permanent magnet 44 with respect to the axis G is 80 ° to 100 ° (100 in this embodiment). °) is desirable.

  One end of the second permanent magnet 44a and one end of the second permanent magnet 44b are separated by, for example, 20 ° in the circumferential direction, and the other end of the second permanent magnet 44a to the other end of the second permanent magnet 44b is, for example, 140 in the circumferential direction. ° Separated. The directions of the magnetic fields of the two second permanent magnets 44a and 44b are set in reverse. When the lower arm 34 is at the home position, the magnetic field directions of the first and second permanent magnets 42a, 44a; 42b, 44b of the opposing groups are opposite to each other. The second magnet housing hole 46 has a bottom wall similar to the bottom wall 20a of the first embodiment. However, the bottom wall may be omitted.

  A second magnetic path forming member 44m made of a magnetic material is incorporated in a portion of the second magnet holding plate 43b that faces the first permanent magnet 42 when the first rotating shaft 33a rotates. The second magnetic path forming member 44m is an arc-shaped holding hole 46b formed in a penetrating manner in the second magnet holding plate 43b, and is fitted and held in a holding hole 46b having the same shape as the second magnet housing hole 46a. Has been. The second magnetic path forming member 44m is for forming a closed loop magnetic path in cooperation with the first permanent magnet 44b when the first rotating shaft 33a rotates.

  As shown in FIGS. 11, 14, and 15, the second assist mechanism 50 sets the upper arm 36 from a predetermined rotation stop position (set rotation position) to at least one of the forward rotation direction and the reverse rotation direction (this embodiment). In the example, when the rocking drive is performed, that is, the second rotation shaft 35a is set to a preset angle from the preset rotation position to at least one of the forward rotation direction and the reverse rotation direction (in this embodiment, about 45 °). ) When rotating, assist torque for reducing the load on the second servo motor 38 is generated.

  The second cyst mechanism 50 is the same as the assist mechanism 10 of the first embodiment except for the size and number of the first and second permanent magnets 52 and 54 and the size and number of the first and second magnet housing holes 19 and 20. Since it is the same structure, it demonstrates easily. The second assist mechanism 50 includes a first support member 51 fixed to the pivot plate 34a, a plurality (six in this embodiment) of first permanent magnets 52 held by the first support member 51, A second support member 54 fixed to the lower end portion of the second rotating shaft 35a and the upper arm 36, and a plurality (six in this embodiment) of second permanent magnets 54 held by the second support member 54. I have.

  The first support member 51 includes a first annular substrate 51a made of a magnetic material, and a first magnet holding plate 51b made of a nonmagnetic material fixed to the first annular substrate 51a. Six first magnet housing holes 55 are formed in the first magnet holding plate 51 b, and six first permanent magnets 52 are housed in the first magnet housing holes 55, respectively. The six first permanent magnets 52a to 52f are arranged at six equal positions on the circumference, and the opening angle of the first permanent magnet 52 with respect to the axis H of the rotating shaft 35a is 40 to 45 ° (45 ° in this embodiment). For example, the end portions of the adjacent first permanent magnets 52 are separated by 15 °, for example. The first magnet housing hole 55 is formed with a bottom wall similar to the bottom wall 19a of the first embodiment. However, the bottom wall may be omitted.

  The second support member 53 includes a second annular substrate 53a made of a magnetic material, and a second magnet holding plate 53b made of a nonmagnetic material fixed to the second annular substrate 53a and the second rotating shaft 35a. . Six second magnet accommodation holes 56 are formed in the second magnet holding plate 53 b, and six second permanent magnets 54 are accommodated in the second magnet accommodation holes 56, respectively. The six second permanent magnets 54a to 54f are arranged at six equal circumferential positions, and the opening angle of the second permanent magnet 54 with respect to the axis H is 40 ° to 45 ° (45 ° in this embodiment). desirable. When the upper arm 36 is at a predetermined rotation stop position, the opposing first and second permanent magnets 52a, 54a; 52b, 54b; 52c, 54c; 52d, 54d; 52e, 54e; The direction of the magnetic field 54f is reversed.

The operation of the first and second assist mechanisms 40 and 50 described above will be described.
When the lower arm 34 of the articulated robot 30 is at the home position, the first assist mechanism 40 has the first and second permanent magnets 42a, 44a; 42b, 44b facing each other. Since the directions of the magnetic fields of the second permanent magnets 42a, 44a; 42b, 44b are opposite, no assist torque is generated.

  When the first servomotor 37 rotates the first rotating shaft 33a in the forward rotation direction (for example, the direction of arrow F in FIGS. 12 and 13) and swings the lower arm 34 upward, the first permanent shaft Assist torque that reduces the load on the first servomotor 37 is generated by the repulsive force acting between the magnet 42a and the second permanent magnet 44a and the attractive force acting between the first permanent magnet 42a and the second permanent magnet 44b. To do. Therefore, it is possible to reduce the size of the first servo motor 37 and to increase the speed of the swinging motion of the lower arm 34.

  When the first rotating shaft 33a rotates 120 ° and the lower arm 34 swings 120 ° upward from the lowest position, the first permanent magnet 42b and the second permanent magnet 44a face each other and no assist torque is generated. However, a holding force for holding the lower arm 24 in that position is generated. When the lower arm 34 returns to the home position, gravity due to the weight of the lower arm 34 and its accessories acts, so that the first servo motor 37 is more than the case of swinging upward as described above. The load does not increase.

  When the upper arm 36 is rotated at the predetermined rotation stop position with respect to the lower arm 34 and the second servomotor 38 rotates the second rotating shaft 35a to swing the upper arm 36 in the forward rotation direction. When swinging in the reverse rotation direction, the load on the second servomotor 38 is reduced by the repulsive force and attractive force of the plurality of first and second permanent magnets 52 and 54, as in the assist mechanism 10 of the first embodiment. Assist torque is generated.

  For this reason, it is possible to increase the speed of the swinging motion of the upper arm 36. When the second rotating shaft 35a rotates 45 degrees, the magnetic field directions of the first and second permanent magnets 52 and 54 of each pair facing each other become the same direction, and an attractive force acts. The holding force that holds the second rotating shaft 35a acts on the rotation position. When the upper arm 36 is swung in the reverse direction from the set rotational position, the assist torque is generated in the same manner as described above. Therefore, the load on the second servo motor 38 is reduced, and the upper arm 36 is swung. It is possible to increase the speed.

Next, an example in which the above embodiment is partially changed will be described.
1) In the assist mechanisms 10, 40, and 50, the size and shape of the first and second permanent magnets may be different. Further, the shape of the first and second permanent magnets is not limited to the arc shape, and various shapes of permanent magnets can be employed.
2) One set of assist mechanisms is not necessarily incorporated into one rotary shaft drive device, but a plurality of sets of assist mechanisms are incorporated at different positions in the axial direction, and the plurality of assist mechanisms cooperate to simultaneously or It is also possible to generate assist torque in order.
3) In the assist mechanism 40, a permanent magnet having the same polarity as the first permanent magnet 42a may be incorporated in place of the first magnetic path forming member 42m in order to enhance the assist torque.

4) It is also possible to incorporate an assist mechanism into the rotary shaft drive device of the part other than the joint part of the articulated robot. Moreover, it is also possible to incorporate an assist mechanism into various rotating shaft driving devices of various mechanical devices other than the indexer device and the articulated robot. By incorporating an assist mechanism, it is possible to speed up the operation. In particular, when a large drive motor is required, it is difficult to speed up the operation only by increasing the size of the drive motor. However, by incorporating the assist mechanism of the present invention, the speed of the operation is increased. It becomes possible.

5) In addition, those skilled in the art can implement the present invention in a form in which various modifications are added to the above-described embodiments without departing from the gist of the present invention. The form is also included.

  The present invention provides a rotary shaft drive device incorporating an assist mechanism capable of reducing a load when rotating a rotary shaft in various rotary shaft drive devices of various mechanical devices.

1 Indexer device 2 Table unit (driven member)
2a, 2b Rotating shafts 2d, 2e Arm 3 Axis support mechanism 5 Rotation drive mechanism 10, 40, 50 Assist mechanism 30 Articulated robot 34 Lower arm (driven member)
36 Upper arm (driven member)
37, 38 First and second servo motors (rotation drive means)
11, 41, 51 First support members 12, 43, 53 Second support members 13, 42, 52 First permanent magnets 14, 44, 54 Second permanent magnets 11a, 41a, 51a First annular substrates 11b, 41b, 51b First magnet holding plate 12a, 43a, 53a Second annular substrate 12b, 43b, 53b Second magnet holding plate
19, 45a, 55 1st magnet accommodation hole 20, 46a, 56 2nd magnet accommodation hole 19a, 20a Bottom wall 33, 35 1st, 2nd joint part 33a, 35a 1st, 2nd rotating shaft 42m, 44m 1st , Second magnetic path forming member

Claims (9)

A rotary shaft, a shaft support mechanism that rotatably supports the rotary shaft, a rotary drive unit that can rotationally drive the rotary shaft in a normal rotation direction and a reverse rotation direction, and swinging about the rotary shaft by the rotary shaft In a rotary shaft driving device having a driven member to be driven,
An annular first support member fixed to the shaft support mechanism and disposed on the outer peripheral side of the rotating shaft;
An annular second support member fixedly connected to the rotating shaft and disposed on the outer peripheral side of the rotating shaft;
A plurality of first permanent magnets held intermittently in the circumferential direction on the first support member and having a magnetic field direction parallel to the axis of the rotary shaft;
Provided with an assist mechanism comprising a plurality of second permanent magnets held intermittently in the circumferential direction on the second support member and having a magnetic field direction parallel to the axis,
The plurality of first permanent magnets and the plurality of second permanent magnets are arranged to be able to face each other in an approaching state in a direction parallel to the axis,
The assist mechanism is configured to rotate the rotation shaft by a set angle from a preset rotation position set in advance to at least one of a normal rotation direction and a reverse rotation direction, and the plurality of first permanent magnets and a plurality of first rotation magnets. 2. A rotary shaft drive device configured to generate an assist torque that reduces the load on the rotary drive means by the magnetic force of a permanent magnet.   2. The rotating shaft drive device according to claim 1, wherein in the plurality of first and second permanent magnets, the direction of the magnetic field of each pair of permanent magnets adjacent in the circumferential direction is set to be opposite. The first support member has a first annular substrate made of a magnetic material, and an annular first magnet holding plate made of a nonmagnetic material fixed to the first annular substrate,
The second support member is a second annular substrate made of a magnetic material and an annular second magnet holding plate made of a non-magnetic material fixed to the second annular substrate, and is between the first magnet holding plate. An annular second magnet holding plate that is adjacent with a minute gap therebetween,
A plurality of first magnet housing holes are intermittently formed in the circumferential direction in the first magnet holding plate, and a plurality of first permanent magnets are housed in the plurality of first magnet housing holes, respectively.
A plurality of second magnet accommodation holes are intermittently formed in the circumferential direction in the second magnet holding plate, and a plurality of second permanent magnets are accommodated in the plurality of second magnet accommodation holes, respectively.
Each first magnet receiving hole is formed with a bottom wall having a thickness of 5 mm or less that closes the second magnet holding plate, and each second magnet receiving hole has a thickness of 5 mm or less that closes the first magnet holding plate. The rotary shaft driving device according to claim 1, wherein a bottom wall is formed.   Each of the plurality of first and second permanent magnets is four permanent magnets disposed at four equally spaced positions in the circumferential direction, and each of the first and second permanent magnets has an opening angle with respect to the axis of the rotating shaft. The rotary shaft driving device according to claim 1, wherein the rotary shaft driving device is formed in an arc shape of 50 to 70 °.   Each of the plurality of first and second permanent magnets is six permanent magnets arranged at six equal positions in the circumferential direction, and each of the first and second permanent magnets has an opening angle with respect to the axis of the rotating shaft. The rotary shaft driving device according to claim 1, wherein the rotary shaft driving device is formed in an arc shape of 40 to 45 °.   Each of the plurality of first and second permanent magnets is two permanent magnets disposed at two of three circumferential positions in the circumferential direction, and each of the first and second permanent magnets has a rotating shaft. The rotary shaft drive device according to claim 1, wherein an opening angle with respect to the axis of the rotary shaft is formed in an arc shape of 80 to 100 °. A first magnetic path forming member made of a magnetic material is incorporated into a portion of the first magnet holding plate that faces the second permanent magnet when the rotating shaft rotates,
The second magnetic path forming member made of a magnetic material is incorporated in a portion of the second magnet holding plate that faces the first permanent magnet when the rotating shaft rotates. The rotating shaft drive device described.   The rotary shaft driving apparatus according to claim 1, wherein the rotary shaft is a rotary shaft installed in a joint portion of the robot, and the driven member is an arm member of the robot.   The rotary shaft drive device according to claim 1, wherein the rotary shaft is a pivot shaft of an indexer device, and the driven member is a table unit of the indexer device.