JP2017030099A - Balancer device for robot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a balancer device for a robot which can be downsized and is improved in versatility and durability.SOLUTION: A balancer device 20 for a robot, which reduces loads on an electric motor that drives a rotating shaft 5 supported rotatably on a shaft supporting member of a robot 1 via a bearing member, comprises: a cam member 21 fixed to the rotating shaft; a cam following member 22 that follows the cam member while coming into contact with the outer peripheral face of the cam member; and an energizing mechanism 23 that energizes the cam following member in a direction in which the cam following member is made to approach the cam member. The energizing mechanism comprises: one guiding mechanism 23A that guides the cam following member movably in a reference direction V in which a rotation center X of the cam member is connected to the rotation center Y of the cam following member; and one energizing means 23B that energizes the cam following member in a direction in which the cam following member is made to approach the cam member. The shaft center of the energizing means 23B is positioned on a straight line V connecting the rotation center of the cam member to the rotation center of the cam following member.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a robot balancer device, and more particularly to a robot balancer device that reduces a load on a rotary drive mechanism including a cam member fixed to the rotary shaft, a cam follower member, and an electric motor that drives the rotary shaft via an urging mechanism. About.

  The rotating shaft that drives the arm member of the robot is subjected to a fluctuating torque that varies from moment to moment due to gravity acting on one or more arm members. Various balancers for robots have been proposed that reduce the load on the rotational drive mechanism caused by this fluctuating torque.

  In the articulated robot described in Patent Document 1, a swivel base is provided on the base, and the lower part of the lower arm is connected to the swivel base, and the base end part of the upper arm is connected to the upper end part of the lower arm, The base end of the gas spring for the balancer is connected to the swivel base, and the upper end of the gas spring is connected to the lower part of the lower arm, and assist torque is adjusted while adjusting the gas pressure of this gas spring according to the load of the drive motor. generate.

  In the robot described in Patent Document 2, an assist torque generating means including a push-type gas spring is provided in a robot similar to the above. The base end portion of the gas spring is connected to the swivel base in front of and below the rotational axis of the lower arm, and the upper end portion of the gas spring is connected to the upper portion of the middle portion of the lower arm.

  On the other hand, in the indexer device described in Patent Document 3, a cam member fixed to the rotating shaft, a cam follower member that abuts on the outer peripheral surface of the cam member, and biases the cam follower member toward the cam member. A balancer device comprising an urging means (gas spring) is employed.

JP 2014-195849 A JP 2015-27713 A JP 2013-32827 A

  The gas springs in the robot balancer devices of Patent Documents 1 and 2 have a considerably large overall length and are arranged outside the outer surface of the lower arm of the articulated robot. Therefore, the outer shape of the lower arm is enlarged and the gas spring becomes an obstacle. .

  The balancer device of Patent Document 1 is excellent in versatility because the gas pressure of the gas spring is adjusted according to the load of the drive motor, but the apparatus for adjusting the gas pressure is complicated and the control becomes troublesome. In the balancer device of Patent Document 2, the weight of the gas spring is also not preferable because it generates variable torque.

  No technology has been proposed for applying the cam type balancer device described in Patent Document 3 to the rotating shaft of a robot. In addition, when a bearing member that supports the rotating shaft is provided only on one side of the cam member, a biasing moment that tilts the rotating shaft about the bearing member is generated by the biasing force that is pressed by the biasing means. The rotation resistance increases, the vibration of the rotating shaft deteriorates, and the durability of the bearing member and the like also decreases.

  An object of the present invention is to provide a robot balancer device that can be miniaturized and has improved versatility and durability.

  The robot balancer device according to claim 1 is a robot balancer device that reduces a load of a rotary drive mechanism including an electric motor that drives a rotary shaft rotatably supported by a shaft support member of a robot via a bearing member. A cam member fixed to the rotating shaft; a cam follow-up member that contacts and follows the outer peripheral surface of the cam member; and a biasing mechanism that biases the cam follow-up member in a direction to approach the cam member. It is characterized by that.

  According to a second aspect of the present invention, there is provided the robot balancer device according to the first aspect, wherein the urging mechanism guides the cam follower member movably in a reference direction connecting the rotation center of the cam member and the rotation center of the cam follower member. And a single urging means for urging the cam follower member in the direction of approaching the cam member, and the shaft center of the urging means is the rotation center of the cam member and the rotation center of the cam follower member. It is characterized by being located on a straight line connecting.

  According to a third aspect of the present invention, there is provided the robot balancer device according to the first aspect, wherein the urging mechanism extends in a direction perpendicular to a reference direction connecting the rotation center of the cam member and the rotation center of the cam follower member and extends in the length direction. A bridging member having the cam follower mounted at the center, a pair of guide mechanisms for movably guiding both ends of the bridging member in a direction parallel to the reference direction, and both ends of the bridging member; And a pair of urging means for urging the cam follower member in a direction to approach the cam member.

  According to a fourth aspect of the present invention, there is provided the robot balancer device according to the second aspect, wherein when the tilting moment for tilting the rotating shaft acts on the rotating shaft around the bearing member by the biasing force of the biasing mechanism. It is characterized by providing a balance moment generating means for generating a balance moment for reducing the above.

  According to a fifth aspect of the present invention, the balancer device for a robot according to the fourth aspect of the present invention is characterized in that the balance moment generating means is provided on the opposite side of the cam following member with the rotation shaft interposed therebetween.

  According to a sixth aspect of the present invention, there is provided the robot balancer device according to the fourth aspect, wherein the balance moment generating means is a rotary roller that rotates in contact with an outer peripheral surface of the rotary shaft or an annular member that is externally fixed to the rotary shaft. Rotating roller urging means for urging the rotating roller toward the rotating shaft is provided.

  According to a seventh aspect of the present invention, there is provided the robot balancer device according to the fourth aspect, wherein the balance moment generating means includes a radial bearing externally fitted to the rotating shaft and one end in contact with the outer peripheral surface of the radial bearing. The cylinder-type urging means provided and a support member for receiving the other end of the cylinder-type urging means are provided.

Since the present invention has the configuration described in the column of problem solving means, the following effects can be obtained.
According to the first aspect of the present invention, a robot balancer device having a simple and compact structure including a cam member, a cam follow-up member, and an urging mechanism and having high versatility and durability can be obtained.

  According to the invention of claim 2, the cam follower can be guided by the guide mechanism so as to move smoothly in the reference direction, and the urging force of the urging means can be efficiently transmitted to the cam follower. The design becomes simple.

  According to the invention of claim 3, since the biasing mechanism includes the bridging member, the pair of guide mechanisms, and the pair of biasing means, the biasing force can be strengthened by the pair of biasing means, A lateral force (force in a direction intersecting the axis of the urging means) acting on the urging means by the pair of guide mechanisms can be reliably supported, and the durability of the urging means can be ensured. The balancer device can be reduced in size by reducing the overall height (or full width) of the balancer device.

  According to the invention of claim 4, since the balance moment generating means for generating the balance moment for reducing the tilting moment for tilting the rotation shaft around the bearing member is provided, the rotation resistance and the shaft vibration are reduced, and the durability of the bearing member is reduced. Can increase the sex.

According to the invention of claim 5, the structure of the balance moment generating means can be simplified.
According to the sixth aspect of the invention, the balance moment generating means includes a rotating roller that rotates in contact with an outer peripheral surface of a rotating shaft or an annular member that is externally fitted and fixed to the rotating shaft, and the rotating roller toward the rotating shaft. Since the rotating roller urging means for urging is provided, the balance moment generating means having a compact structure can be provided.

  According to the invention of claim 7, the balance moment generating means includes a radial bearing externally fitted to the rotary shaft, and a cylinder-type biasing means having one end disposed in contact with the outer peripheral surface of the radial bearing, Since the support member for receiving the other end of the cylinder-type urging means is provided, the number of members can be reduced and the balance moment generating means having a compact structure can be obtained.

1 is a front view of an articulated robot and a balancer device thereof according to a first embodiment of the present invention. It is a side view of the articulated robot containing the principal part longitudinal cross-sectional view. It is a front view of the articulated robot of Example 2 and its balancer apparatus. It is the longitudinal cross-sectional view of the balancer apparatus for robots of Example 3, and its surrounding structure. It is the VV sectional view taken on the line of FIG.

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

  This embodiment relates to a robot balancer device 20 that reduces the load on a rotary drive mechanism including a servo motor 6 that rotationally drives a lower arm 4 of an articulated robot 1. In FIG. 1 and FIG. 2, explanation will be made by defining the arrow L as the left, the arrow R as the right direction, the arrow F as the front, and the arrow B as the rear.

  As shown in FIGS. 1 and 2, the articulated robot 1 has a base portion 2, a swivel base 3, a swivel base drive servo motor 3 m, a lower arm 4, and a base end portion of the lower arm 4 fixed. A rotating shaft 5 having a horizontal axis, a lower arm driving servo motor 6 that rotationally drives the rotating shaft 5 fixed to the lower arm 4, and a base end portion of the lower arm 4 at the distal end portion via the rotating shaft. The upper arm 7 connected to the upper arm 7, the upper arm rotational drive servomotor 8, the wrist member 9 connected to the tip of the upper arm 7, and the wrist rotational drive servo that rotationally drives the wrist member 9. A motor 10, a hand unit 11 rotatably mounted on the wrist member 9, a hand rotation driving servo motor 12 that rotationally drives a proximal end portion of the hand unit 11, and the like are provided.

  The swivel base 3 and the rotary shaft 5 are equipped with a robot balancer device 20 and a balance moment generating means 40. The servo motor 6 is fixed to the motor mounting wall 3w of the swivel base 3, and the servo motor 6, its speed reducer 6a, and the rotating shaft 5 have a common horizontal axis.

  The rotary shaft 5 includes a large-diameter shaft portion 5a, a medium-diameter shaft portion 5b extending forward from the front end of the large-diameter shaft portion 5a, and a small-diameter shaft portion extending forward from the front end of the medium-diameter shaft portion 5b to the inside of the speed reducer 6a. 5c. The medium-diameter shaft portion 5b is rotatably supported by the swivel base 3 through a bearing member 5e.

  The robot balancer device 20 is a rotary drive mechanism including an electric motor 6 that drives a rotary shaft 5 that is rotatably supported by a swivel 3 of a robot 1 (which corresponds to a shaft support member) via a bearing member 5e. It is a device that reduces the load. The robot balancer device 20 includes a cam member 21 fixed to the rotating shaft 5, a cam follower member 22 that follows the outer peripheral surface of the cam body 21 b of the cam member 21, and a cam follower member 22. And a biasing mechanism 23 for biasing in a direction approaching 21.

  The cam member 21 is externally fitted to the rotary shaft 5 and is fixed to be relatively non-rotatable via a key 21c, and a plate cam-like cam main body 21b integrally formed with the cylindrical portion 21a. It has. The cam main body 21b is formed in a vertically symmetrical shape with respect to a horizontal plane H passing through the axis X (rotation center X of the cam member 21) of the rotary shaft 5 in FIG. 1, and the outer peripheral surface of the cam main body 21b has a shape of The distance from the rotation center X to the point A of the cam member 21 is the smallest, the distance from the rotation center X to the point B is the largest, and the distance from the rotation center X to the point A to the point B gradually increases. It has a shape. The shape of the cam body 21b is preferably set to a shape corresponding to the load characteristics of the load acting on the rotating shaft 5.

  The urging mechanism 23 guides the cam follower 22 with one guide mechanism 23A that guides the cam follower 22 movably in a reference direction V connecting the rotation center X of the cam follower 21 and the rotation center Y of the cam follower 22. One urging means 23B that urges the cam member 21 in a direction approaching the cam member 21 is provided. The axis of the biasing means 23B is located on a straight line V connecting the rotation center X of the cam member 21 and the rotation center Y of the cam follower member 22.

Next, the urging mechanism 23 will be described.
First, the guide mechanism 23A will be described.
A cylindrical member 24 is fixed to the swivel base 3 on the upper side of the large-diameter shaft portion 5a of the rotary shaft 5, and a vertical cylindrical hole 25 is formed in the tubular member 24 and the swivel base 3. A lower portion 25 is formed of a bush 26 made of a low friction metal material. A sliding hole 26a having a circular cross section is formed in the bush 26, and a cylindrical outer shape for holding the cam follower member 22 is formed in the sliding hole 26a. A holding member 27 is mounted so as to be movable up and down.

  A rectangular groove 28 penetrating in the left-right direction is formed in the lower end portion of the holding member 27, and a cam follower member 22 made of a roller member is attached to the rectangular groove 28. The cam follower member 22 has a support pin 29 in the front-rear direction. It is rotatably supported via.

  A rotation restricting mechanism 30 is provided that restricts the rotation so that the holding member 27 does not rotate about its axis. The rotation restricting mechanism 30 includes a vertical groove 31 formed in a side surface portion of the upper end side portion of the holding member 27, a distal end portion engaged with the vertical groove 31, and fixed to the tubular member 24 with a plurality of bolts 32 a. And a regulating member 32.

Next, the biasing means 23B will be described.
A mounting hole 27a having a circular cross section is formed in the upper part of the upper side of the holding member 27, and a gas spring 33 as an urging means is slidably mounted in the inverted posture in the cylindrical mounting hole 27a. . The gas spring 33 is configured to urge the output rod 33b downward in the advancing direction by high-pressure compressed gas accommodated in the cylinder body 33a. A lid member 34 that closes the upper end of the mounting hole 27a is fixed to the cylindrical member 24 with a plurality of bolts 34a, the upper end portion of the cylinder body 33a of the gas spring 33 is received by the lid member 34, and the lower end of the output rod 33b is the mounting hole. The gas spring 33 urges the holding member 27 and the cam follower member 22 closer to the cam member 21 by abutting against the bottom wall of 27a.

Next, the balance moment generating means 40 will be described.
Since the rear portion of the rotating shaft 5 relative to the cam member 21 is not supported by the bearing member, a tilting moment that tilts the rotating shaft 5 about the bearing member 5e acts on the rotating shaft 5 by the biasing force of the biasing mechanism 23B. To do. Balance moment generating means 40 for generating a balance moment for reducing the tilting moment is provided. The balance moment generating means 40 is provided on the opposite side of the cam follower member 22 (directly below the rotary shaft 5) with the rotary shaft 5 interposed therebetween.

  The balance moment generating means 40 includes a rotating roller 41 that rotates in contact with the outer peripheral surface of the rotating shaft 5 or an annular member (cylindrical portion 21a of the cam member 21) that is fitted and fixed to the rotating shaft 5, and the rotating roller 41. Rotating roller urging means for urging the rotating shaft 5 toward the rotating shaft 5, and the rotating roller urging means is constituted by a spring unit 42 that urges the elastic roller by the elastic force of the compression spring. The spring unit 42 includes a holding member 43 and a compression spring 44. The holding member 43 has a cylindrical outer shape, and a rotating roller 41 is rotatably supported on the upper end portion of the holding member 43 by a support pin 41 a facing in the front-rear direction. The holding member 43 is attached to the sliding hole 45a of the cup member 45 fixed to the swivel base 3 so as to be slidable up and down.

  Inside the holding member 43, a compression spring 44 is mounted between the top wall of the holding member 43 and the bottom wall of the cup member 45, and the holding member 43 and the rotating roller 41 are elastically biased upward by the compression spring 44. The rotating roller 41 is strongly pressed against the cylindrical portion 21a of the cam member 21 (this corresponds to an annular member). In addition, you may comprise so that the outer peripheral surface of the rotating shaft 5 may be pressed directly with the rotating roller 41. FIG.

  A rotation restricting mechanism 46 is provided that restricts the rotation of the holding member 43 so that the holding member 43 does not rotate about its axis. The rotation restricting mechanism 46 includes a short vertical slit formed in the side wall of the lower end portion of the holding member 43, and a restricting member 46a having a front end engaged with the vertical slit and fixed to the cup member 45 by a plurality of bolts 46b. It consists of and.

  Here, the distance from the bearing member 5e to the center of the width of the cam follower 22 is C, the distance from the bearing member 5e to the center of the width of the rotating roller 41 is D, and the cam follower 22 presses the cam main body 21b. The pressing force Fd is set so as to satisfy the following expression, where Fd is a pressing force with a strong pressing force Fc (force in the reference direction V) and Fd is a pressing force with which the rotating roller 41 presses the cylindrical portion 21a.

Fc × C (tilting moment) = Fd × D (balance moment) (1)
In this way, the tilting moment acting on the rotating shaft 5 is configured to be offset or reduced with the balance moment. Note that the average pressing force Fc as described above is that the advancement amount of the output rod 33b of the gas spring 33 changes according to the rotational phase of the cam main body 21b at the portion where the cam follow-up member 22 abuts. This is because the gas pressure of the compressed gas varies and the pressing force Fc also varies.

The operation and effect of the robot balancer device 20 will be described.
At any moment when the rotating shaft 5 rotates, the pressing force (normal force) of the cam follower member 22 is N, the pressure angle is α, and the distance from the rotation center X of the rotating shaft 5 to the point of application of the pressing force is R. Then, the balancer device 20 generates an assist torque that is proportional to the pressing force N, the distance R, and sin α and that reduces the load on the rotary drive mechanism including the servo motor 6.

  A robot balancer device 20 having a simple and small structure including the cam member 21, the cam follower member 22, and the urging mechanism 23 and having high versatility and durability can be obtained. The biasing mechanism 23 includes one guide mechanism 23A that guides the cam follower member 22 so as to be movable in the reference direction V, and one biasing unit 23B that biases the cam follower member 22 in a direction approaching the cam member 21. Therefore, the cam follower member 22 is guided by the guide mechanism 23A so as to move smoothly in the reference direction V, and the urging force of the urging means 23B can be transmitted to the cam follower member 22 efficiently. The design becomes simple.

  Since the balance moment generating means 40 for generating the balance moment for reducing the tilting moment for tilting the rotating shaft 5 around the bearing member 5e is provided, the rotational resistance and shaft vibration can be reduced, and the durability of the bearing member 5e can be increased. . Since the balance moment generating means 40 is provided on the opposite side of the cam follower member 22 with the rotating shaft 5 interposed therebetween, the structure of the balance moment generating means 40 can be simplified.

  The balance moment generating means 40 includes a rotating roller 41 that rotates in contact with an outer peripheral surface of the rotating shaft 5 or an annular member (cylindrical portion 21a) that is fitted and fixed to the rotating shaft 5, and the rotating roller 41 that rotates the rotating shaft 5 Since the spring unit 42 urged by the elastic force of the compression spring 44 is provided, the balance moment generating means 40 having a compact structure can be obtained.

  Since the configuration of the multi-joint robot 1A according to the second embodiment is the same as that of the multi-joint robot 1 according to the first embodiment except for the urging mechanism 51, the same components are denoted by the same reference numerals and the description thereof is omitted. The configuration of the cam member 21 of the articulated robot balancer device 50 is the same as that of the cam member 21 of the first embodiment.

  The urging mechanism 51 of the balancer device 50 extends in a direction perpendicular to the reference direction V connecting the rotation center of the cam member 21 and the rotation center of the cam follower member 22, and the cam follower member 22 is mounted at the center in the length direction. A bridge member 52, a pair of guide mechanisms 53 for guiding both ends of the bridge member 52 in a direction parallel to a reference direction (indicated by the vertical line V), and both ends of the bridge member 52 are cams. A pair of urging means 54 that urges the follower member 22 in a direction approaching the cam member 21 is provided.

  The swivel base 3 has a lower swivel base 3A and an upper swivel base 3B fixed to the lower swivel base 3A. A rotary shaft 5 is mounted on the upper swivel base 3B, and a servo motor that drives the rotary shaft 5 to rotate. A rotary drive mechanism including (not shown) is mounted on the upper swivel base 3B. An accommodation space 3s for accommodating the balancer device 50 is formed inside the upper swivel base 3B.

  Each guide mechanism 53 is fixed to the bottom wall of the upper swivel base 3B and protrudes to the corner of the accommodation space 3s. The guide member 53 has a vertical posture and a cylindrical guide member 55 that is slidable in the vertical direction. A cylindrical member 56 that is fitted and extends upward, and includes a top wall portion 56a; a low-friction bushing 57 made of a bearing metal that is mounted on the inner peripheral portion of the lower portion of the cylindrical member 56; A sliding hole 58 is formed in the bush 57 and through which the guide member 55 is slidably inserted in the vertical direction.

  Each urging means 54 is a gas spring 59 mounted in the cylindrical member 56, and is constituted by a gas spring 59 mounted between the upper end surface of the guide member 55 and the top wall portion 56 a of the cylindrical member 56. . The gas spring 59 has a cylinder body 59a and an output rod 59b protruding from the upper end of the cylinder body 59a. The cylinder body 59a is filled with compressed gas, and the output rod 59b is urged in the protruding direction by the compressed gas. ing.

  The bridging member 52 extends in a horizontal direction perpendicular to the reference direction, and the lower part of the cylindrical member 56 is fixed to both ends of the bridging member 52, and the lower end of each cylindrical member 56 is engaged with the lower surface of the bridging member 52. An engaging flange 56b is formed. A cam follower member 22 is rotatably mounted at the center of the bridging member 52 in the length direction, and is in contact with the lower end of the cam body 21b of the cam member 21.

  Since the pair of biasing means 54 strongly biases the pair of cylindrical members 56 upward, both ends of the bridging member 52 are strongly biased upward, and the cam follower 22 is applied to the cam member 21. As with the balancer device 20 of the first embodiment, the assist torque that reduces the load of the rotary drive mechanism including the servo motor (not shown) is generated.

Next, the balance moment generating means 60 will be briefly described.
An inverted cup member 61 is fixed with a plurality of bolts to the outer edge of the opening at the center of the top wall of the upper swivel base 3B, and about 2/3 of the upper side of the holding member 62 is vertically moved into the cup member 61. The holding member 62 is urged downward by a rotating roller urging means. The rotating roller urging means is constituted by a spring unit 60 a including a compression spring 63 mounted in the holding member 62.

  A rotating roller 64 is attached to the lower end portion of the holding member 62, and the rotating roller 64 is in contact with the outer peripheral surface of the tubular portion 21 a of the cam member 21 at a position behind the cam member 21. This balance moment generating means 60 generates a balance moment similar to the balance moment generating means 40 of the first embodiment.

According to the balancer device 50, the biasing mechanism 51 includes the bridging member 52, the pair of guide mechanisms 53, and the pair of biasing means 54. The lateral force acting on the biasing means 54 (the force in the direction intersecting the axis of the biasing means) is reliably supported by the pair of guide mechanisms 53, and the durability of the biasing means 54 is improved. It can be secured.
Since the pair of guide mechanisms 53 and the pair of urging means 54 are disposed at positions spaced laterally from the vertical line V, the overall height (or the entire width) of the balancer device 50 is reduced, and the balancer device 50 is reduced in size. be able to.

  The third embodiment relates to a balancer device 100 having the same function as the robot balancer device 50 of the articulated robot 1 of the second embodiment. The robot balancer device 100 is a device that reduces the load on a rotary drive mechanism that includes an electric motor that drives a rotary shaft 101 that is rotatably supported by a shaft support member (a case member 102 corresponding to a swivel).

  As shown in FIGS. 4 and 5, the rotating shaft 101 is rotatably supported by the case member 102 by a pair of roller bearings 103 and 104. A pressing member 105 that presses the outer race of the roller bearing 103 is fixed to the case member 102 by a plurality of bolts 105 a, and a seal member 106 is attached to the inner peripheral portion of the pressing member 105. On the rear end side of the rotating shaft 101, a closing member 107 is fixed to the case member 102 with a plurality of bolts 107a. A housing space 108 for housing the balancer device 100 is formed inside the case member 102.

Next, the robot balancer device 100 will be described with reference to FIGS.
The balancer device 100 includes a cam member 62 fixed to a rotating shaft, a rotatable cam follower member 63 that follows the outer peripheral surface 62s of the cam member 62 and follows the cam member 62, and the cam follower member 63 approaches the cam member 62. And an urging mechanism 110 for urging in the direction to move.

  The urging mechanism 110 extends in a direction orthogonal to a reference direction (a direction indicated by the vertical line V) connecting the rotation center A of the cam member 62 and the rotation center B of the cam follower member 63 and is camped at a central portion in the length direction. The bridging member 120a to which the follower member 63 is mounted, a pair of guide mechanisms 130 for guiding both ends of the bridging member 120a in a direction parallel to the reference direction, and both ends of the bridging member 120a are cam-followed. And a pair of urging means 140 for urging the member 63 in the direction in which the member 63 approaches the cam member 62.

  The cam member 62 is the same as the cam member 21 of the first embodiment, and is a cylindrical portion 62b that is externally fitted to the rotary shaft 101 and restricted by a key 62a, and a cam that is integrally formed with the cylindrical portion 62b. And a main body 62c.

  The bridging member 120a is configured by a part of the rectangular frame member 120 that surrounds the outer peripheral side of the rotating shaft 101 and the cam member 62 (for example, about ３ part on the upper side). About 2/3 of the lower side of the rectangular frame member 120 constitutes a reinforcing member 120b that reinforces the bridging member 120a and suppresses the elastic deformation of the bridging member 120a. However, the reinforcing member 120b is not essential and can be omitted.

  The thickness of the rectangular frame member 120 in the left-right direction is set to about 1.5 to 2.0 times the outer diameter of a gas spring 141 described later. The outer shape of the rectangular frame member 120 is a rectangle, and a rectangular opening 121 is formed in the center side portion of the rectangular frame member 120, and four corners of the rectangular opening 121 are formed in a quarter arc of a predetermined radius. . The rectangular opening 121 has a vertical width smaller than the horizontal width, and the rectangular opening 121 has a vertical width larger than the major diameter of the cam member 62.

  Each guide mechanism 130 includes a vertical hole 131 having a circular cross section formed in parallel with the reference direction V (vertical direction) at both ends in the front-rear direction of the bridging member 120a, and a bush mounted on the inner peripheral wall portion of the vertical hole 131. 133 is provided with a vertically-oriented sliding hole 133 a formed in 133, and a columnar guide member 132 that is slidably inserted into the sliding hole 133 a and fixed to the case member 102.

  The guide member 132 is fixed to the lower end of the closing member 134 that closes the circular hole of the top wall 102d of the case member 102 with a bolt or the like. The closing member 134 is detachably fixed by fixing its flange to the top wall 102d with a plurality of bolts 134a. By removing the closing member 134, the guide member 132 can be removed.

  Each urging means 140 includes a gas spring 141 that functions as the guide member 132. The gas spring 141 is slidably inserted into the vertical hole 131 and the sliding hole 133a, and the cylinder body guides the bridging member 120a in a direction parallel to the reference direction V through the sliding hole 133a. . Compressed gas is accommodated inside the cylinder main body of the gas spring 141, and the output rod 141a is strongly urged downward by the compressed gas. The output rod 141a protrudes from the lower end of the cylinder main body, and slides 131. The bridge member 120a is urged elastically and strongly downward. A breathing hole 131 a communicating with the lower end of the sliding hole 131 is also formed.

Next, the tilt prevention plate 125 will be described with reference to FIG.
A pair of anti-tilt plates 125 are provided on the left and right sides of the cam member 62, the cam follower member 63, and the rectangular frame member 120, and are attached to the rotary shaft 101 so as to rotate integrally with the rotary shaft 101. Yes. Each tilt prevention plate 125 is a member such as an annular plate, and a boss portion 125a that is externally fitted and fixed to the rotary shaft 101 is formed on the center side portion of the tilt prevention plate 125, and on the outer diameter side of the boss portion 125a. Is formed with an annular plate portion 125b that smoothly contacts most of the surface of the rectangular frame member 120.

  A boss portion 125 a of the left tilt prevention plate 125 is externally fitted to the rotating shaft 101 and is sandwiched between the cylindrical portion 62 b of the cam member 62 and the inner race of the ball bearing 151. A boss portion 125 a of the right tilt prevention plate 125 is externally fitted to the rotary shaft 101 and is sandwiched between the cylindrical portion 62 b of the cam member 62 and the inner race of the roller bearing 111.

  The cam follower member 63 and the bridging member 120a in the vicinity thereof are sandwiched between the annular plate portions 125b of the pair of anti-tilt plates 125 to restrict the position thereof, so that they do not move in the left-right direction. ing. Since most of the reinforcing member 120b of the rectangular frame member 120 is also sandwiched between the annular plate portions 125b of the pair of tilt prevention plates 125 and is regulated in position, the reinforcing member 120b also does not move in the left-right direction. Guided. Note that the pair of tilt prevention plates 125 is not essential for the robot balancer device 100 and can be omitted.

Next, the balance moment generating means 150 will be described with reference to FIG.
The balance moment generating means 150 applies to the rotating shaft 101 a pressing force in the direction opposite to the pressing force of the cam following member 63 pressing the cam member 62 on the side opposite to the cam following member 63 with respect to the axis of the rotating shaft 101. The balance moment that reduces the tilting moment that tilts the rotating shaft 101 is caused to act. A radial ball bearing 151 is mounted on the rotary shaft 101 in the vicinity of the left side of the left tilt prevention plate 125, and the inner race of the ball bearing 151 is sandwiched between the inner race of the roller bearing 103 and the boss portion 125a.

  Immediately below the ball bearing 151, the case member 102 is formed with a mounting hole 152 having a vertical circular section, and a gas spring 153 as a cylinder-type biasing means is mounted in the mounting hole 152. A closure member 154 (which corresponds to a support member) is attached to the portion, and a flange at the lower end of the closure member 154 is fixed to the case member 102 with a plurality of bolts 154a. The upper end of the cylinder body of the gas spring 153 contacts the outer race of the ball bearing 151, and the output rod 153a of the gas spring 153 protrudes from the lower end of the cylinder body and contacts the closing member 154.

  The cylinder body of the gas spring 153 is filled with compressed gas, and the compressed gas strongly biases the output rod 153a downward. The load acting on the rotary shaft 101 from the pair of gas springs 141 of the balancer device 100 varies according to the rotational phase of the cam member 62. Therefore, the pressing force of the gas spring 153 of the balance moment generating mechanism 150 is set to a pressing force substantially equal to the average load acting on the rotating shaft 101 from the pair of gas springs 141. However, the pressing force may be set larger or smaller than the average load.

This robot balancer device 100 basically has the same operations and effects as the balancer device 50 of the second embodiment. Furthermore, since the bridging member 120a is reinforced by the reinforcing member 120b, elastic deformation of the bridging member 120a can be suppressed.
In addition, since the bridging member 120a and the reinforcing member 120b are sandwiched between the pair of tilt prevention plates 125, the bridging member 120a and the reinforcing member 120b are prevented from tilting in the front-rear direction, so that the balancer apparatus 100 can operate stably. improves. Further, since the guide member 132 is constituted by the gas spring 141 which is the urging means 140, the number of members can be reduced and the manufacturing cost can be reduced.

Next, an example in which the above embodiment is partially changed will be described.
1) In the first, second, and third embodiments, instead of the gas spring that biases the cam follower member, a spring unit that incorporates a compression spring or an air cylinder that is driven by supplying pressurized air may be employed. Is possible.
2) The shape of the cam member of the balancer device is not limited to that described in the above embodiment, and it is desirable to set the shape according to the load characteristics of the load acting on the rotating shaft.

  3) In the balance moment generating means 40, 60 of the first and second embodiments, a gas spring may be employed instead of the spring units 42, 60a.

4) The rotary shaft 5 of Embodiments 1 and 2 may be supported by bearings on both sides of the balancer devices 20 and 50, and the balance moment generating means may be omitted.
5) Since the rotating shaft 101 of the third embodiment is supported by a pair of roller bearings 103 and 104 on both sides of the balancer device 100, the balance moment generating means 150 may be omitted.

6) A balancer device similar to the above may be provided that reduces the load on the rotation drive mechanism that rotates the upper arm of the articulated robot around the rotation shaft.
7) In addition, those skilled in the art can implement the present invention in various forms with various modifications without departing from the spirit of the present invention, and the present invention includes such modifications. is there.

1,1A articulated robot 3 swivel (shaft support member)
5,101 Rotating shaft 5e Bearing member 6 Electric motor 20, 50, 100 Balancer device 21 Cam member 21a Tube portion (annular member)
22, 63 Cam follow-up members 23, 51, 110 Biasing mechanism 23A Guide mechanism 23B Biasing means 40 Balance moment generating means 41 Rotating roller 42, 60a Spring unit 51 Biasing mechanism 52, 120a Bridging member 53, 130 Guide mechanism 54, 140 Biasing means 40, 60, 150 Balance moment generating means 62 Cam member 102 Case member (shaft support member)
120 Rectangular frame member 132 Guide member 133 Bush 141 Gas spring 151 Radial ball bearing 153 Cylinder-type biasing means 154 Closure member (support member)

Claims (7)

In a robot balancer device that reduces the load of a rotary drive mechanism including an electric motor that drives a rotary shaft that is rotatably supported by a shaft support member of a robot via a bearing member.
A cam member fixed to the rotating shaft;
A cam follow-up member that contacts and follows the outer peripheral surface of the cam member;
A robot balancer device comprising: an urging mechanism that urges the cam follower member in a direction to approach the cam member. The biasing mechanism includes one guide mechanism that guides the cam follower member in a reference direction that connects the rotation center of the cam member and the rotation center of the cam follower member, and a direction in which the cam follower member approaches the cam member. One biasing means for biasing,
2. The robot balancer device according to claim 1, wherein an axis of the biasing unit is located on a straight line connecting a rotation center of the cam member and a rotation center of the cam follower member. The biasing mechanism is
A bridging member extending in a direction orthogonal to a reference direction connecting the rotation center of the cam member and the rotation center of the cam follower member, and having the cam follower member mounted at the center in the length direction; A pair of guide mechanisms that guide the movable member in a direction parallel to a reference direction and a pair of urging means that urges both ends of the bridging member in a direction in which the cam follower member approaches the cam member. The robot balancer device according to claim 1, wherein:   When a biasing moment that tilts the rotating shaft acts on the rotating shaft around the bearing member by the biasing force of the biasing mechanism, there is provided a balance moment generating means for generating a balancing moment that reduces the tilting moment. The robot balancer device according to claim 2, wherein the balancer device is a robot balancer.   5. The robot balancer device according to claim 4, wherein the balance moment generating means is provided on the opposite side of the cam follower member with the rotation shaft interposed therebetween.   The balance moment generating means includes a rotating roller that rotates in contact with an outer peripheral surface of the rotating shaft or an annular member that is externally fitted to the rotating shaft, and the rotating roller is attached to the rotating shaft by the elastic force of a compression spring. The robot balancer device according to claim 4, further comprising a spring unit for biasing.   The balance moment generating means includes a radial bearing externally fitted to the rotating shaft, a cylinder-type urging means having one end disposed in contact with the outer peripheral surface of the radial bearing, and the cylinder-type urging means. The robot balancer device according to claim 4, further comprising a support member that receives the other end of the robot.