JP6654308B2 - Robot balancer device - Google Patents

Description

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

  A fluctuating torque that fluctuates every moment due to gravity acting on one or a plurality of arm members acts on a rotating shaft that drives an arm member of the robot. Various types of balancers for robots have been proposed that reduce the load on the rotary drive mechanism due to the fluctuating torque.

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

  In the robot described in Patent Literature 2, the same robot as described above is provided with an assist torque generating unit including a push-type gas spring. The base end of the gas spring is connected to the swivel base forward and below the rotation axis of the lower arm, and the upper end of the gas spring is connected to the upper part of the middle part of the lower arm.

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

JP-A-2014-195849 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, so that the outer shape of the lower arm becomes large 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 equipment for adjusting the gas pressure is also complicated and control is troublesome. In the balancer device of Patent Literature 2, the weight of the gas spring is also not preferable because it also generates a fluctuation torque.

  No technique has been proposed in which a cam-type balancer device described in Patent Document 3 is applied to a rotating shaft of a robot. In addition, when the bearing member for supporting the rotating shaft is provided only on one side of the cam member, a tilting moment for tilting the rotating shaft about the bearing member is generated by the biasing force pressed by the biasing means, and the rotating shaft is rotated. , The rotational resistance of the rotary shaft increases, the vibration of the rotary shaft also deteriorates, and the durability of the bearing member and the like also decreases.

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

The balancer device for a robot according to claim 1, wherein the load balance of a rotary drive mechanism including an electric motor that drives a rotary shaft rotatably supported via a bearing member on a shaft support member of the robot is reduced. A cam member fixed to the rotating shaft and formed of a plate cam orthogonal to the rotating shaft axis, wherein a distance from the rotating shaft axis to one end of the one end and the other end sandwiching the rotating shaft axis is equal to the other end. A cam member having an outer peripheral surface having a distance different from the distance, and a cam follower member abutting on and following the outer peripheral surface of the cam member , the cam follower member having an outer peripheral surface, being orthogonal to a horizontal plane including the rotation axis, and having a rotation axis. A cam follower having a rotation axis parallel to the rotation axis on a vertical plane, and a biasing mechanism for biasing the cam follower in a direction to approach the cam member, wherein the biasing mechanism is , wherein the cam follower And a single guide mechanism for movably guiding the reference direction connecting the centers of rotation and the cam follower member of the cam member in the rotary shaft axial direction position corresponding to the thickness center of the cam member, the cam follower member A biasing means for biasing the bearing member in a direction to approach the cam member, wherein the axial center of the biasing means is oriented in the reference direction, and the biasing force of the biasing mechanism centers the bearing member. When a tilt moment for tilting the rotary shaft acts on the rotary shaft, a balance moment generating means for generating a balance moment for reducing the tilt moment is provided.

The robot balancer device according to claim 2 is a robot balancer device that reduces a load on a rotary drive mechanism that includes an electric motor that drives a rotary shaft rotatably supported via a bearing member on a shaft support member of the robot. A cam member fixed to the rotating shaft and formed of a plate cam orthogonal to the rotating shaft axis, wherein a distance from the rotating shaft axis to one end of the one end and the other end sandwiching the rotating shaft axis is equal to the other end. A cam member having an outer peripheral surface having a distance different from the distance, and a cam follower member abutting on and following the outer peripheral surface of the cam member , the cam follower member having an outer peripheral surface, being orthogonal to a horizontal plane including the rotation axis, and having a rotation axis. A cam follower having a rotation axis parallel to the rotation axis on a vertical plane, and a biasing mechanism for biasing the cam follower in a direction to approach the cam member, wherein the biasing mechanism is , the thickness of the cam member It said cam follower member is mounted on and midspan portion extending in a direction perpendicular to the reference line to either side of the reference line connecting the centers of rotation and the cam follower member of the cam member in the rotary shaft axial direction position corresponding to the heart A bridging member, a pair of guide mechanisms for movably guiding both ends of the bridging member in a direction parallel to the reference line, and a direction in which both ends of the bridging member move the cam follower member closer to the cam member. A pair of biasing means for biasing the rotating shaft to reduce the tilting moment when the biasing force of the biasing mechanism causes the rotating shaft to tilt the rotating shaft about the bearing member. A balance moment generating means for generating a balance moment is provided.

  According to a third aspect of the present invention, in the robot balancer device according to the first or second aspect, the balance moment generating means is provided on a side opposite to the cam follower member with respect to the rotation shaft.

  According to a fourth aspect of the present invention, there is provided the robot balancer device according to the first aspect, wherein the balance moment generating means includes a rotating roller that rotates by contacting an outer peripheral surface of the rotating shaft or an annular member externally fixed to the rotating shaft. And a rotating roller biasing means for biasing the rotating roller toward the rotating shaft.

  According to a fifth aspect of the present invention, in the robot balancer device according to the second aspect, the balance moment generating means includes a radial bearing externally fitted to the rotary shaft, and one end abutting on an outer peripheral surface of the radial bearing. It is characterized by comprising a provided cylinder-type urging means and a support member for receiving the other end of the cylinder-type urging means.

The invention of the present application has the following effects because it has the configuration described in the section of problem solving means.
According to the first aspect of the present invention, it is possible to obtain a robot balancer device having a simple and compact structure including a cam member, a cam follower member, and an urging mechanism, and having high versatility and durability.

  Then, the cam follower is 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, thereby simplifying the design of the cam member. Further, since the balance moment generating means for generating the balance moment for reducing the tilting moment of tilting the rotating shaft about the bearing member is provided, the rotation resistance and the shaft vibration can be reduced, and the durability of the bearing member can be increased.

  According to the second aspect of the present invention, since the urging mechanism includes the bridging member, the pair of guide mechanisms, and the pair of urging means, the urging force can be strengthened by the pair of urging means, The pair of guide mechanisms reliably supports the lateral force (force in the direction intersecting the axis of the urging means) acting on the urging means, and ensures the durability of the urging means. By reducing the overall height (or overall width) of the balancer device, the size of the balancer device can be reduced.

  Further, since the balance moment generating means for generating the balance moment for reducing the tilting moment of tilting the rotating shaft about the bearing member is provided, the rotation resistance and the shaft vibration can be reduced, and the durability of the bearing member can be increased.

According to the invention of claim 3, the structure of the balance moment generating means can be simplified.
According to the fourth aspect of the present invention, the balance moment generating means includes: a rotating roller that rotates while being in contact with the outer peripheral surface of the rotating shaft or the annular member externally fixed to the rotating shaft; and rotating the rotating roller toward the rotating shaft. Since the rotating roller biasing means for biasing is provided, the compact moment generating means can be a compact structure.

  According to the invention of claim 5, the balance moment generating means includes: a radial bearing externally fitted to the rotating shaft; and a cylinder-type biasing means having one end disposed in contact with the outer peripheral surface of the radial bearing. The provision of the supporting member for receiving the other end of the cylinder type urging means makes it possible to reduce the number of members and provide a balance moment generating means having a compact structure.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view of an articulated robot according to a first embodiment of the present invention and its balancer device and the like. FIG. 2 is a side view of the articulated robot including a main part longitudinal sectional view. FIG. 9 is a front view of the articulated robot according to the second embodiment and a balancer device thereof. FIG. 10 is a longitudinal sectional view of a robot balancer device and a peripheral structure according to a third embodiment. FIG. 5 is a sectional view taken along line VV of FIG. 4.

  Embodiments for carrying out the present invention will be described based on embodiments.

  The present embodiment relates to a robot balancer device 20 that reduces the load on a rotary drive mechanism including a servomotor 6 that drives the lower arm 4 of the articulated robot 1 to rotate. 1 and 2, arrow L is defined as left, arrow R is defined as right, arrow F is defined as forward, and arrow B is defined as backward.

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

  The turntable 3 and the rotating shaft 5 are equipped with a robot balancer device 20 and balance moment generating means 40. The servo motor 6 is fixed to the motor mounting wall 3w of the swivel 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 into the reduction gear 6a. 5c. The middle diameter shaft portion 5b is rotatably supported by the swivel 3 via a bearing member 5e.

  The robot balancer device 20 includes a rotary drive mechanism including an electric motor 6 that drives a rotary shaft 5 rotatably supported on a swivel 3 of the robot 1 (this corresponds to a shaft support member) via a bearing member 5e. This 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 abuts and follows an outer peripheral surface of a 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 the reference numeral 21.

The cam member 21 has a cylindrical portion 21a which is externally fitted to the rotary shaft 5 and is fixed so as to be relatively non-rotatable via a key 21c, and a plate cam shape which is formed integrally with the cylindrical portion 21a and is orthogonal to the axis of the rotary shaft. And a cam main body 21b. The cam body 21b is formed in a vertically symmetrical shape with respect to a horizontal plane H passing through the axis X of the rotation shaft 5 (the rotation center X of the cam member 21) in FIG. The distance from the rotation center X of the cam member 21 to the point A (one end) is the smallest, the distance from the rotation center X to the point B (the other end) is the largest, and the distance from the rotation center X to the point A to the point B is Is gradually increased. It is desirable that the shape of the cam body 21b is set to a shape according to the load characteristics of the load acting on the rotating shaft 5.

The cam follower member 22 has an outer peripheral surface, and has a rotation axis perpendicular to a horizontal plane H including the rotation axis and parallel to the rotation axis on a vertical plane including the rotation axis.
The urging mechanism 23 sets the cam follower 22 at the rotation center X and the rotation center Y of the cam member 21 at a position in the rotation axis direction corresponding to the center of the thickness of the cam body 21 b of the cam member 21. and one guide mechanism 23A for movably guiding the reference direction V connecting, and a single biasing means 23B for biasing direction toward the cam follower member 22 to the cam member 21. The axis of the urging means 23B is located on the straight line indicated by the reference direction 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.
Above the large-diameter shaft portion 5a of the rotating shaft 5, a cylindrical member 24 is fixed to the turntable 3, and a vertical cylindrical hole 25 is formed in the cylindrical member 24 and the turntable 3. The lower part of 25 is formed of a bush 26 made of a low-friction metal material. The bush 26 is formed with a sliding hole 26a having a circular cross section. The sliding hole 26a has a cylindrical outer shape for holding the cam follower 22. Holding member 27 is mounted to be vertically movable.

  A rectangular groove 28 penetrating in the left-right direction is formed at the lower end of the holding member 27, and a cam follow-up member 22 composed of a roller member is mounted in the rectangular groove 28. The cam follow-up member 22 has a support pin 29 directed in the front-rear direction. It is rotatably supported via

  A rotation restricting mechanism 30 for restricting rotation of the holding member 27 so as not to rotate around its axis is provided. The rotation restricting mechanism 30 has a vertical groove 31 formed in a side surface of an upper end 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 urging means 23B will be described.
A mounting hole 27a having a circular cross section is formed in about 2/3 of the upper side of the holding member 27, and a gas spring 33 serving as a biasing means is mounted in the cylindrical mounting hole 27a in an inverted posture and slidably. . The gas spring 33 is configured to urge the output rod 33b downward in the forward direction by high-pressure compressed gas housed inside the cylinder body 33a. A lid member 34 for closing the upper end of the mounting hole 27a is fixed to the tubular member 24 with a plurality of bolts 34a, the upper end 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 connected to the mounting hole. The gas spring 33 abuts the holding member 27 and the cam follow-up member 22 so as to be strongly urged toward the cam member 21.

Next, the balance moment generating means 40 will be described.
Since a portion of the rotary shaft 5 behind the cam member 21 is not supported by the bearing member, a tilting moment for tilting the rotary shaft 5 about the bearing member 5e acts on the rotary shaft 5 by the urging force of the urging mechanism 23B. I do. A 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 rotating shaft 5 from the cam follower member 22 (directly below the rotating shaft 5).

  The balance moment generating means 40 includes: a rotating roller 41 that rotates while abutting on the outer peripheral surface of the rotating shaft 5 or an annular member (the cylindrical portion 21 a of the cam member 21) externally fixed to the rotating shaft 5; And a rotating roller biasing means for biasing the rotating roller 5 toward the rotating shaft 5. The rotating roller biasing means is constituted by a spring unit 42 for biasing the elastic roller with the elastic force of a 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 41a oriented in the front-rear direction. The holding member 43 is vertically slidably mounted in a sliding hole 45 a of a cup member 45 fixed to the swivel 3.

  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 urged 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). The outer peripheral surface of the rotating shaft 5 may be directly pressed by the rotating roller 41.

  A rotation restricting mechanism 46 for restricting the rotation of the holding member 43 so as not to rotate around its axis is provided. The rotation restricting mechanism 46 includes a short vertical slit formed in a side wall of a lower end portion of the holding member 43, and a restricting member 46a having a distal end engaged with the vertical slit and fixed to the cup member 45 with a plurality of bolts 46b. It is composed of

  Here, the distance from the bearing member 5e to the center of the width of the cam following member 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 average that the cam following member 22 presses the cam body 21b. Assuming that the pressing force is Fc (force in the reference direction V) and the pressing force of the rotating roller 41 pressing the cylindrical portion 21a is Fd, the pressing force Fd is set so as to satisfy the following expression.

Fc × C (tilting moment) = Fd × D (balance moment) (1)
Thus, the tilting moment acting on the rotating shaft 5 is offset or reduced by the balance moment. Note that the average pressing force Fc is set as described above because the amount of advance of the output rod 33b of the gas spring 33 changes according to the rotation phase of the cam main body 21b at the position where the cam follower 22 contacts. This is because the gas pressure of the compressed gas fluctuates and the pressing force Fc also fluctuates.

The operation and effect of the above-described 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 the sin α, and that reduces the load on the rotary drive mechanism including the servomotor 6.

  The 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 urging mechanism 23 includes one guide mechanism 23A that guides the cam follower 22 movably in the reference direction V and one urging unit 23B that urges the cam follower 22 in a direction approaching the cam member 21. Accordingly, the guide mechanism 23A guides the cam follower 22 to move smoothly in the reference direction V, and the urging force of the urging means 23B can be efficiently transmitted to the cam follower 22. Design is also simplified.

  Since the balance moment generating means 40 for generating a balance moment for reducing the tilting moment of tilting the rotating shaft 5 about the bearing member 5e is provided, rotation 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 across the rotary shaft 5, 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 by abutting on the outer peripheral surface of the rotating shaft 5 or an annular member (cylindrical portion 21 a) externally fixed to the rotating shaft 5. And the spring unit 42 biased by the elastic force of the compression spring 44, the balance moment generating means 40 having a compact structure can be provided.

  Regarding the articulated robot 1 </ b> A according to the second embodiment (see FIG. 3), the configuration other than the urging mechanism 51 is the same as the articulated robot 1 according to the first embodiment. 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 biasing mechanism 51 of the balancer device 50 is a reference connecting the rotation center of the cam member 21 and the rotation center of the cam follower member 22 at a position in the direction of the rotation axis corresponding to the center of the thickness of the cam body 21 b of the cam member 21. A bridging member 52 extending in a direction orthogonal to the reference line on both sides of the line and having a cam follower 22 mounted at the center of the span, and both ends of the bridging member 52 are parallel to the reference line (indicated by a vertical line V). And a pair of biasing means 54 for biasing both ends of the bridging member 52 in a direction in which the cam follower member 22 approaches the cam member 21. I have.

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

  Each guide mechanism 53 is fixed to the bottom wall of the upper revolving base 3B, and has a vertical columnar guide member 55 protruding from the corner of the accommodation space 3s. A tubular member 56 fitted and extending upward and having a top wall portion 56a; a metal low-friction bushing 57 for a bearing mounted on an inner peripheral portion below the tubular member 56; A slide hole 58 formed in the bush 57 and through which the guide member 55 is slidably inserted in a vertical direction.

  Each of the 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 56a of the cylindrical member 56. . The gas spring 59 has a cylinder body 59a and an output rod 59b projecting from the upper end of the cylinder body 59a. The cylinder body 59a is filled with compressed gas, and the compressed gas urges the output rod 59b in the projecting direction. ing.

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

  Since the pair of urging means 54 strongly urge the pair of cylindrical members 56 upward, both ends of the bridging member 52 are strongly urged upward, and the cam follower member 22 is pressed against the cam member 21. It is strongly pressed and generates an assist torque that reduces the load on a rotary drive mechanism including a servomotor (not shown), similarly to the balancer device 20 of the first embodiment.

Next, the balance moment generating means 60 will be briefly described.
An inverted cup member 61 is fixed to the outer edge of the opening at the center of the top wall of the upper swivel 3B with a plurality of bolts, and approximately two-thirds of the upper side of the holding member 62 is moved up and down inside the cup member 61. The holding member 62 is strongly 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 mounted on the lower end of the holding member 62, and the rotating roller 64 is in contact with the outer peripheral surface of the cylindrical portion 21 a of the cam member 21 at a position behind the cam member 21. The balance moment generating means 60 generates the same balance moment as the balance moment generating means 40 of the first embodiment.

According to the balancer device 50, since the urging mechanism 51 includes the bridging member 52, the pair of guide mechanisms 53, and the pair of urging means 54, the urging force is generated by the pair of urging means 54. And a pair of guide mechanisms 53 reliably support the lateral force (force in the direction intersecting the axis of the urging means) acting on the urging means 54, and improve the durability of the urging means 54. Can be secured.
Since the pair of guide mechanisms 53 and the pair of biasing means 54 are arranged at positions laterally separated from the vertical line V, the overall height (or overall width) of the balancer device 50 is reduced, and the size of the balancer device 50 is reduced. 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 including an electric motor that drives a rotary shaft 101 rotatably supported by a shaft support member (a case member 102 corresponding to a swivel table).

  As shown in FIGS. 4 and 5, the rotating shaft 101 is rotatably supported by a case member 102 by a pair of roller bearings 103 and 104. A holding member 105 for holding the outer race of the roller bearing 103 is fixed to the case member 102 with a plurality of bolts 105a, and a seal member 106 is attached to an inner peripheral portion of the holding 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. An accommodation space 108 for accommodating 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 63 that contacts and follows an outer peripheral surface 62s of the cam member 62, and moves the cam follower 63 closer to the cam member 62. And a biasing mechanism 110 for biasing in the direction of rotation.
The cam member 62 is similar to the cam member 21 of the first embodiment, and includes a cylindrical portion 62b which is externally fitted to the rotating shaft 101 and whose rotation is restricted by the key 62a, and a cam integrally formed with the cylindrical portion 62b. And a main body 62c. The cam follower 63 is similar to the cam follower 22 of the first embodiment.

The biasing mechanism 110 is a reference line connecting the rotation center A of the cam member 62 and the rotation center B of the cam follower 63 at a position in the direction of the rotation axis corresponding to the center of the thickness of the cam body 62c of the cam member 62 . A bridging member 120a extending in a direction orthogonal to the reference line on both sides and having a cam follower 63 mounted at the center of the span, and both ends of the bridging member 120a are parallel to the reference line (the direction indicated by the vertical line V). And a pair of biasing means 140 for biasing both ends of the bridging member 120a in a direction in which the cam follower 63 approaches the cam member 62. .

  The bridging member 120a is configured by a part (for example, about one-third of the upper side) of the rectangular frame member 120 surrounding the outer periphery of the rotating shaft 101 and the cam member 62. 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 in the left-right direction of the rectangular frame member 120 is set to about 1.5 to 2.0 times the outer diameter of the 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 a central portion of the rectangular frame member 120, and four corners of the rectangular opening 121 are formed into a quarter-arc having a predetermined radius. . The vertical width of the rectangular opening 121 is smaller than the horizontal width, and the vertical width of the rectangular opening 121 is 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 at both ends in the front-rear direction of the bridging member 120a in parallel with the reference direction V (vertical direction), and a bush attached to the inner peripheral wall of the vertical hole 131. The sliding member 133 includes a vertical sliding hole 133a formed therein, and a cylindrical guide member 132 that is slidably inserted into the sliding hole 133a and fixed to the case member 102.

  The guide member 132 is fixed to a lower end of a closing member 134 for closing a 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 biasing means 140 is constituted by a gas spring 141 functioning as the guide member 132. The gas spring 141 is slidably inserted into the vertical hole 131 and the sliding hole 133a, and guides the bridge member 120a movably in a direction parallel to the reference direction V via the sliding hole 133a by its cylinder body. . Compressed gas is contained in the cylinder body of the gas spring 141, and the output rod 141a is strongly urged downward by the compressed gas, and the output rod 141a projects from the lower end of the cylinder body and slides into the sliding hole 131. And strongly urges the bridging member 120a elastically downward. Note that a breathing hole 131a 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 both left and right sides of the cam member 62, the cam follower member 63, and the rectangular frame member 120, and are mounted on the rotating shaft 101 so as to rotate integrally with the rotating shaft 101. I have. Each tilt prevention plate 125 is a member like an annular plate, and a boss portion 125a externally fitted to and fixed to the rotation shaft 101 is formed at a center side portion of the tilt prevention plate 125, and a boss portion 125a is formed on an 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.

  The boss portion 125a of the left tilt prevention plate 125 is externally fitted to the rotating shaft 101 and is sandwiched between the cylindrical portion 62b of the cam member 62 and the inner race of the ball bearing 151. The boss portion 125 a of the right tilt prevention plate 125 is externally fitted to the rotation 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 63 and the bridging member 120a in the vicinity thereof are sandwiched between the annular plate portions 125b of the pair of tilt prevention plates 125 to regulate the position thereof, thereby guiding them so as not to move in the left and right direction. ing. 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 preventing plates 125 and the position thereof is regulated, so that the reinforcing member 120b does not move in the left-right direction. You are being guided. Note that the pair of tilt prevention plates 125 is not essential to 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 a pressing force in a direction opposite to the pressing force of the cam follower 63 to the cam member 62 on the rotary shaft 101 on the side opposite to the cam follower 63 with respect to the axis of the rotary shaft 101. By acting, a balance moment for reducing a tilting moment for tilting the rotating shaft 101 is provided. A radial ball bearing 151 is mounted on the rotating shaft 101 near 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 125a.

  Immediately below the ball bearing 151, a vertical mounting hole 152 having a circular cross section is formed in the case member 102, and a gas spring 153 as a cylinder-type urging means is mounted in the mounting hole 152. A closing member 154 (corresponding to a supporting member) is attached to the portion, and a flange at the lower end of the closing 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 projects 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 a compressed gas, and the compressed gas strongly urges the output rod 153a downward. The load acting on the rotating shaft 101 from the pair of gas springs 141 of the balancer device 100 varies according to the rotation 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 to be larger or smaller than the average load.

The robot balancer device 100 basically has the same operation and effect as the balancer device 50 of the second embodiment. Further, since the bridging member 120a is reinforced by the reinforcing member 120b, elastic deformation of the bridging member 120a can be suppressed.
Further, since the bridging member 120a and the reinforcing member 120b are sandwiched by the pair of tilt preventing plates 125, the bridging member 120a and the reinforcing member 120b do not tilt in the front-rear direction, so that the operation stability of the balancer device 100 is improved. improves. Further, since the guide member 132 is constituted by the gas spring 141 serving as 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, a spring unit having a built-in compression spring or an air cylinder driven by supplying pressurized air may be used instead of the gas spring that biases the cam follower. It is possible.
2) The shape of the cam member of the balancer device is not limited to the shape described in the above embodiment, but is desirably set to a 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 rotating shafts 5 of the first and second embodiments may be supported by bearings on both sides of the balancers 20, 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 to reduce the load on the rotary drive mechanism that drives the rotary shaft to rotate the upper arm of the articulated robot.
7) In addition, those skilled in the art can implement various modifications to the above-described embodiment 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 Rotation shaft 5e Bearing member 6 Electric motor 20,50,100 Balancer device 21 Cam member 21a Tube portion (annular member)
22, 63 cam follower members 23, 51, 110 biasing mechanism 23A guide mechanism 23B biasing means 40 balance moment generating means 41 rotating rollers 42, 60a spring unit 51 biasing mechanism 52, 120a bridge members 53, 130 guide mechanism 54, 140 urging 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 urging means 154 closing member (support member)

Claims (5)

In a robot balancer device for reducing the load on a rotary drive mechanism including an electric motor that drives a rotary shaft rotatably supported via a bearing member on a shaft support member of the robot,
A cam member fixed to the rotating shaft and formed of a plate cam orthogonal to the rotating shaft axis, wherein a distance from the rotating shaft axis to one end of the one end and the other end sandwiching the rotating shaft axis is equal to the other end. A cam member having an outer peripheral surface different from the distance ,
A cam follower member that abuts and follows the outer peripheral surface of the cam member , and has a peripheral surface and is perpendicular to a horizontal plane including the rotational axis and perpendicular to the horizontal plane including the rotational axis. A cam follower having a parallel rotation axis ;
An urging mechanism for urging the cam follower member in a direction to approach the cam member,
The urging mechanism guides the cam follower movably in a reference direction connecting the rotation center of the cam member and the rotation center of the cam follower at a position in the rotation axis direction corresponding to the center of the thickness of the cam member. One guide mechanism, and one biasing means for biasing the cam follower in a direction to approach the cam member,
The axis of the urging means is oriented in the reference direction,
When a biasing moment for inclining the rotary shaft acts on the rotary shaft around the bearing member by the biasing force of the biasing mechanism, balance moment generating means for generating a balance moment for reducing the tilting moment is provided. Characteristic balancer device for robots. In a robot balancer device for reducing the load on a rotary drive mechanism including an electric motor that drives a rotary shaft rotatably supported via a bearing member on a shaft support member of the robot,
A cam member fixed to the rotating shaft and formed of a plate cam orthogonal to the rotating shaft axis, wherein a distance from the rotating shaft axis to one end of the one end and the other end sandwiching the rotating shaft axis is equal to the other end. A cam member having an outer peripheral surface different from the distance ,
A cam follower member that abuts and follows the outer peripheral surface of the cam member , and has a peripheral surface and is perpendicular to a horizontal plane including the rotational axis and perpendicular to the horizontal plane including the rotational axis. A cam follower having a parallel rotation axis ;
An urging mechanism for urging the cam follower member in a direction to approach the cam member,
The urging mechanism extends in a direction orthogonal to the reference line to both sides of a reference line connecting the rotation center of the cam member and the rotation center of the cam follower member at a position in the direction of the rotation axis corresponding to the thickness center of the cam member, and A bridge member in which the cam follower member is mounted at the center of the span, a pair of guide mechanisms for guiding both ends of the bridge member movably in a direction parallel to the reference line, and both ends of the bridge member; A pair of urging means for urging the cam follower member in a direction to approach the cam member,
When a biasing moment for inclining the rotary shaft acts on the rotary shaft around the bearing member by the biasing force of the biasing mechanism, balance moment generating means for generating a balance moment for reducing the tilting moment is provided. Characteristic balancer device for robots.   3. The balancer device for a robot according to claim 1, wherein the balance moment generating unit is provided on a side opposite to the cam follower member with respect to the rotation shaft. 4.   The balance moment generating means includes: a rotating roller that rotates in contact with the outer peripheral surface of the rotating shaft or an annular member externally fixed to the rotating shaft; and applies the rotating roller toward the rotating shaft by the elastic force of a compression spring. The balancer device for a robot according to claim 1, further comprising a biasing spring unit.   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 an outer peripheral surface of the radial bearing; and a cylinder-type urging means. The balancer device for a robot according to claim 2, further comprising a support member that receives the other end of the robot.