JP2020082247A - Articulated robot - Google Patents

Abstract

To provide an articulated robot in which outgassing does not occur, and which comprises a balancer capable of suppressing an increase in size of a robot.SOLUTION: An articulated robot 100 comprises: a robot arm 4 including one or more joints which connects a pair of links, which are adjacent to each other, in plural links 1 to 3 so as to be relatively rotatable around respective rotation axes; and a balancer 14 which is provided between a pair of links 2, 3a which are connected to be rotatable around a prescribed rotation axis AL of one or more joints, and generates a moment against a load moment due to a self weight of the robot arm 4 at a tip side link 3a near a tip. The articulated robot further comprises: a first pulley 11 which are provided on a base end side link 2, which is far from the tip, of the pair of links 2, 3a so as to be rotatable around a first rotation axis A1; a second pulley 12 which is provided on the tip side link 3a so as to be rotatable around a second rotation axis A2; and an annular rubber-like elastic component 13 which is wound around the first pulley 11 and the second pulley 12.SELECTED DRAWING: Figure 1

Description

The present invention relates to an articulated robot.

In an articulated robot, a gravity balancer is used to cancel the load moment due to the gravity received by the arm.

As such a gravity balancer, a gas balancer (for example, refer to Patent Document 1) and a spring balancer (for example, refer to Patent Document 2) are known.

Japanese Patent Laid-Open No. 2014-195854 Japanese Patent Laid-Open No. 2001-225293

However, there is a possibility that gas outflow may occur in the gas balancer. Further, since the spring balancer has a large size, the robot tends to be large.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a multi-joint robot including a balancer that does not cause outgassing and can suppress an increase in size of the robot. ..

The present inventors diligently studied to solve the above problems. In this study, the inventors of the present invention focused on rubber as a material for a member that generates a moment against the load moment due to gravity received by the arm of the robot. Since rubber was not previously durable enough, it was not considered for use in balancers, but rubbers with sufficient durability are now available. If the spring is made of rubber, there is no risk of gas escape. Moreover, the size of the spring made of rubber is equal to or smaller than that of the coil spring.

Therefore, the inventors of the present invention have conceived to use rubber as a material of a member for generating a moment in the arm that resists a load moment due to gravity received by the arm of the robot.

An articulated robot according to an aspect of the present invention connects a plurality of links and a pair of adjacent links of the plurality of links so as to be relatively rotatable about respective rotation axis lines. Between a robot arm including the above-mentioned joints and a pair of links rotatably connected about the predetermined rotation axis by a joint having a predetermined rotation axis among the one or more joints. A balancer that is provided and that generates a moment against the load moment around the predetermined rotation axis due to the weight of the robot arm on the tip side link near the tip of the pair of links, the balancer, A first pulley provided on a proximal end side link distant from the tip of the pair of links so as to be rotatable about a first rotation axis parallel to the predetermined rotation axis; and the predetermined rotation. A second pulley provided on the distal end side link so as to be rotatable about a second rotation axis parallel to the axis, and an annular rubber-like elastic member wound around the first pulley and the second pulley. And Here, "pulley" means a grooved wheel that can rotate around an axis. A pulley is mentioned as a typical example of the "pulley", but the "pulley" may be "a pulley with a groove that can rotate around an axis" other than the pulley.
The "rubber-like elastic member" means a member made of a polymer compound having elasticity. The “polymer compound having elasticity” includes natural rubber and synthetic rubber.

According to this structure, the rubber-like elastic body is a member that generates a moment (hereinafter referred to as a gravity counter moment) against a load moment around a predetermined rotation axis due to the weight of the robot arm. The rubber-like elastic body has no risk of gas escape. The size of the spring using the rubber-like elastic body is equal to or smaller than that of the coil spring. Therefore, it is possible to provide a multi-joint robot that includes a balancer that does not cause gas outflow and that can prevent the robot from increasing in size.

Further, the balancer has a first pulley provided on the proximal side link so as to be rotatable about a first rotation axis parallel to the predetermined rotation axis, and a second rotation parallel to the predetermined rotation axis. Since the annular rubber-like elastic member is wound around the second pulley provided on the tip side link so as to be rotatable about the axis, the robot arm rotates about a predetermined rotation axis. Then, the balancer rotates around the first rotation axis, and in response to the rotation of the balancer, the first pulley and the second pulley do not bend the annular rubber-like elastic member wound around them. Thus, they rotate about the first rotation axis and the second rotation axis, respectively. This prevents the rubber-like elastic member from bending due to the rotation of the robot arm. Further, even if the rubber-like elastic member expands and contracts in accordance with the rotation of the balancer to change the cross-sectional area (cross-sectional shape), the rubber-like elastic member can be firmly held by the pair of pulleys at both ends of the balancer. .. Further, at this time, the axial displacement of the rubber-like elastic member is automatically corrected by the axial movement of the first pulley and the second pulley.

The robot arm has a base portion which is the link fixed to an object to be fixed, a swing portion which is the proximal end link which is rotatably connected to the base portion around a swing axis, and the predetermined rotation. A lower arm portion that is an axial line and is the distal end side link that is rotatably connected to the swivel portion about a lower arm pivot axis that is perpendicular to the swivel axis; Is provided between the lower arm part and the lower arm part, and generates a moment against the load moment around the lower arm rotation axis due to the own weight of the robot arm in the lower arm part, wherein the first pulley is The second pulley is rotatably provided on the swivel unit about the first rotation axis parallel to the lower arm rotation axis, and the second pulley is parallel to the lower arm rotation axis. It may be provided on the lower arm portion so as to be rotatable around a moving axis.

With this configuration, it is possible to generate a gravity counter moment on the lower arm.

The robot arm includes a base portion that is the link fixed to a fixed object, a swing portion that is rotatably connected to the base portion around a swing axis line, and a lower arm rotation axis line that is perpendicular to the swing axis line. A lower arm portion that is rotatably connected to the swivel portion and is the base end side link, and a swivel around an upper arm swivel axis that is the predetermined swivel axis and is perpendicular to the swivel axis. The balancer is provided between the lower arm portion and the upper arm portion, the upper arm portion being the tip side link connected to the lower arm portion, and the upper arm rotation due to the weight of the robot arm. A moment against the load moment around the dynamic axis is generated in the upper arm portion, and the first pulley is rotatably movable around the first rotation axis parallel to the upper arm rotation axis. The second pulley may be provided on the arm portion, and the second pulley may be provided on the upper arm portion so as to be rotatable around the second rotation axis line parallel to the upper arm rotation axis line.

With this configuration, it is possible to generate a gravity counter moment on the upper arm.

A plurality of the annular rubber-like elastic members may be wound around the first pulley and the second pulley.

According to this configuration, by adjusting the number of rubber-like elastic members, it is possible to easily adjust the gravity counter moment by the balancer. Further, when one of the plurality of rubber-like elastic members is cut, the remaining rubber-like elastic member can maintain the function of the balancer to some extent, and by replacing the cut rubber-like elastic member with a normal one. , Immediately, the balancer can be returned to the normal state.
The plurality of annular rubber-like elastic members may have different elastic coefficients.

According to this structure, the gravity counter moment of the balancer can be precisely adjusted by appropriately selecting the elastic coefficient of the rubber-like elastic member.

A tension adjusting sheave is provided on the base end side link or the tip end side link so as to be rotatable about a third rotation axis parallel to the predetermined rotation axis, and the tension adjustment sheave includes the tension adjustment sheave. At least one linear portion of the annular rubber-like elastic member wound around the first pulley and the second pulley is located between the first pulley and the second pulley. It may be provided so as to be bent when viewed from the extending direction so that the position in the direction intersecting with the one linear portion can be adjusted.

According to this configuration, by adjusting the position of the tension adjusting pulley in the direction intersecting with one linear portion, the degree of bending of the one linear portion is adjusted, and by extension, the tension of the rubber-like elastic member is adjusted. be able to.

An intermediate pulley is provided on the base end side link so as to be rotatable around a fourth rotation axis parallel to the predetermined rotation axis, and the intermediate pulley includes the first pulley and the second pulley. A pair of linear portions located between the first pulley and the second pulley of the annular rubber-like elastic member wound around and viewed from the extending direction of the predetermined rotation axis, It may be provided so as to be bent.

According to this configuration, since the annular rubber-like elastic member wound around the first pulley and the second pulley can be bent when viewed from the extending direction of the predetermined rotation axis, the rubber-like elastic member is It is possible to avoid interference with other members located in the space between the virtual position of the rubber-like elastic member and the bent rubber-like elastic member when it is assumed that the rubber-like elastic member is not bent.

Further, as an important effect, according to this configuration, when the robot arm rotates about a predetermined rotation axis, when the balancer rotates in the bending direction of the rubber elastic member, the rubber elastic member is A situation may occur in which the intermediate pulley is not contacted. On the other hand, when the balancer rotates in the direction opposite to the bending direction of the rubber-like elastic member, the rubber-like elastic member is bent more largely by the intermediate pulley. The gravity counteracting moment due to the balancer in the latter state is larger than the gravity counteracting moment due to the balancer in the former state. Therefore, according to this configuration, an asymmetric gravity counter moment can be generated in the robot arm by the balancer depending on the rotation direction of the robot arm.

The balancer may be covered with a cover member.

According to this configuration, the balancer can be protected.

INDUSTRIAL APPLICABILITY The present invention has an effect of being able to provide an articulated robot that includes a balancer that does not cause outgassing and can prevent the robot from increasing in size.

FIG. 1 is a side view schematically showing an example of the configuration of an articulated robot according to a first embodiment of the present invention. FIG. 2 is a sectional view schematically showing a vertical section of the balancer of FIG. FIG. 3 is a side view schematically showing a state in which the arm portion of the articulated robot of FIG. 1 is rotated about the lower arm rotation axis. FIG. 4 is a side view schematically showing an example of the configuration of the articulated robot according to the second embodiment of the present invention. FIG. 5 is a side view schematically showing another example of the configuration of the articulated robot according to the second embodiment of the present invention. FIG. 6 is a side view schematically showing an example of the configuration of an articulated robot according to Embodiment 3 of the present invention. FIG. 7 is a side view schematically showing a state in which the arm part of the articulated robot of FIG. 6 is rotated about the lower arm rotation axis. FIG. 8 is a side view schematically showing an example of the configuration of an articulated robot according to Embodiment 4 of the present invention. FIG. 9 is a side view schematically showing an example of the configuration of the articulated robot according to the fifth embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following, the same or corresponding elements will be denoted by the same reference symbols throughout the drawings, without redundant description. Further, since the following figures are diagrams for explaining the present invention, if elements unrelated to the present invention are omitted, if dimensions are not accurate due to exaggeration, etc., if simplified, in a plurality of figures, There are cases where the elements do not match. Moreover, the present invention is not limited to the following embodiments. Further, in the following, a case where the base portion 1 of the robot arm 4 is installed so that the turning axis line AS is vertical will be exemplified. Therefore, in FIGS. 1 and 3 to 9, the vertical direction of the drawings indicates the vertical direction. ..

(Embodiment 1)
FIG. 1 is a side view schematically showing an example of the configuration of an articulated robot according to a first embodiment of the present invention. FIG. 2 is a sectional view schematically showing a vertical section of the balancer of FIG. FIG. 2 shows a cross section along the straight line LV in FIG.

[Constitution]
Referring to FIG. 1, the articulated robot 100 of this embodiment includes a robot arm 4 and a balancer 14. The robot arm 4 includes a base portion 1, a turning portion 2, and an arm portion 3.

The articulated robot 100 is, for example, a vertical articulated robot. The base 1 is fixed to an object to be fixed (for example, a floor, a truck, etc.). The swivel part 2 is connected to the base part 1 so as to be rotatable about the swivel axis AS. The turning axis AS extends, for example, so as to pass through the central portions of the base portion 1 and the turning portion 2.

The robot arm 4 is composed of a plurality of links connected by one or more joints. Here, the robot arm 4 includes links forming the base 1, a link forming the revolving unit 2, a link forming the lower arm 3a, and a link forming the upper arm 3b in order from the bottom (see FIGS. 8 and 9). , A link (not shown) that constitutes the wrist.

The lower arm 3a, the upper arm 3b, and the wrist form an arm. The lower end of the lower arm 3a is rotatably connected to the swivel unit 2 about a predetermined lower arm rotation axis AL. The lower arm rotation axis AL extends, for example, so as to pass through the central portion of the lower end portion of the lower arm portion 3a in a direction perpendicular to the turning axis AS. The lower arm portion 3a is connected to the turning portion 2 so that the lower arm rotation axis line AL is located away from the turning axis line AS. The lower arm portion 3a may be connected to the turning portion 2 such that the lower arm rotation axis line AL is located on the turning axis line AS.

Hereinafter, a case where the base portion 1 of the robot arm 4 is installed so that the turning axis AS is vertical will be described. However, the installation mode of the robot arm 4 is not limited to this. For example, the base 1 of the robot arm 4 may be installed on a wall or the like so that the turning axis AS is horizontal. The present embodiment is similarly applied to these cases.

In the following, the balancer 14 is provided with a pulley as a pulley, but the pulley may be "a grooved wheel that can rotate around an axis" other than the pulley.

The balancer 14 includes a base end pulley (base end pulley) 11, a front end pulley (front end pulley) 12, and an annular rubber-like elastic member 13. The arrangement of the proximal pulley 11 and the distal pulley 12 will be described below, but this is an example, and the arrangement of the proximal pulley 11 and the distal pulley 12 may be appropriately changed according to the design of the articulated robot 100. , Designed.

The proximal pulley 11 is provided on the swivel unit 2 so as to be rotatable about a first rotation axis A1 that is parallel to the lower arm rotation axis AL. The proximal pulley 11 is provided, for example, such that the first rotation axis A1 is located on the side opposite to the lower arm rotation axis AL with respect to the turning axis AS and away from the turning axis AS. The proximal pulley 11 is provided, for example, so as to be located below the lower arm rotation axis AL.

Referring to FIG. 2, the proximal pulley 11 includes an annular first guide groove 21 around which the rubber elastic member 13 is wound, a first rotary shaft insertion hole 22, and a first bearing 23. ing. The first guide groove 21 is provided coaxially with the first rotary shaft insertion hole 22. The first guide groove 21 is formed such that one or more rubber-like elastic members 13 are wound in parallel. Here, the first guide groove 21 is formed so that three rubber-like elastic members 13 are wound in parallel. The plurality (here, three) of rubber-like elastic members 13 are designed to have the same specifications.

A first bearing 23 is provided on the inner peripheral surface of the first rotary shaft insertion hole 22. On the other hand, the swivel unit 2 is provided with a first rotation shaft 25 coaxially with the first rotation axis A1. The proximal pulley 11 is fitted into the first rotary shaft 25 such that the first rotary shaft 25 is inserted into the first rotary shaft insertion hole 22. After this fitting, the regulating member 26 is attached to the tip of the first rotating shaft 25, and the proximal pulley 11 is regulated so as not to come off from the first rotating shaft 25. With this configuration, the proximal pulley 11 is fixed to the swivel portion 2 via the first bearing 23 and the first rotary shaft 25 so as to be rotatable about the first rotary axis A1.

Referring to FIG. 1, the tip pulley 12 is provided on the lower arm portion 3a so as to be rotatable around a second rotation axis A2 that is parallel to the lower arm rotation axis AL. The distal end pulley 12 is provided, for example, so that the second rotation axis A2 is located on the same side as the first rotation axis A1 with respect to the lower arm rotation axis AL and apart from the lower arm rotation axis AL. Has been. Further, in FIG. 1, the lower arm portion 3a is substantially upright. Hereinafter, the state in which the lower arm portion 3a is substantially upright is referred to as "upright state". The front-end pulley 12 is provided, for example, so as to be located below the lower arm rotation axis AL in the lower arm portion 3a in the upright state. It should be noted that the tip end pulley 12 may be provided so that the second rotation axis A2 is located away from the lower arm rotation axis AL, and the second rotation axis A2 will not be set with respect to the lower arm rotation axis AL. Whether to be located on the side (direction) is appropriately set according to the operable area of the arm unit 3. In the configuration example of FIG. 1, assuming that the arm unit 3 rotates about the lower arm rotation axis AL in the left-right direction in FIG. 3 within a predetermined angle range, the second rotation axis A2 moves downward. It is set to be located on the above-mentioned side (direction) with respect to the arm rotation axis line AL.

Referring to FIG. 2, the front-end pulley 12 has an annular second guide groove 31 around which the rubber-like elastic member 13 is wound, a second rotary shaft insertion hole 32, and a second bearing 33. There is. The second guide groove 31 is provided coaxially with the second rotary shaft insertion hole 32. The second guide groove 31 is formed such that one or more rubber-like elastic members 13 are wound in parallel. The second guide groove 31 is formed here so that three rubber-like elastic members 13 are wound in parallel. A first bearing 23 is provided on the inner peripheral surface of the first rotary shaft insertion hole 22. On the other hand, the lower arm portion 3 is provided with a second rotation shaft 35 coaxial with the second rotation axis A2. The distal pulley 12 is fitted into the second rotary shaft 35 such that the second rotary shaft 35 is inserted into the second rotary shaft insertion hole 32. After this fitting, the regulation member 36 is attached to the tip of the second rotating shaft 35, and the tip side pulley 12 is regulated so as not to come off from the second rotating shaft 35. With this configuration, the front-end pulley 12 is fixed to the lower arm portion 3 via the second bearing 33 and the second rotation shaft 35 so as to be rotatable around the second rotation axis A2.

The distal pulley 12 is provided such that the second guide groove 31 and the first guide groove 21 of the proximal pulley 11 are located on substantially the same plane. The diameter of the second guide groove 31 of the distal pulley 12 may be the same as or different from the diameter of the first guide groove 21 of the proximal pulley 11.

In the configuration example of FIG. 1, when viewed from the extending direction of the lower arm rotation axis AL, the straight line LV connecting the first rotation axis A1 and the second rotation axis A2 is the first rotation axis A1 and the lower arm rotation. The tension of the rubber-like elastic member 13 is minimized when the angle θ intersecting the straight line LN connecting to the moving axis AL is zero degrees. To be precise, the straight line LV represents a plane including the first rotation axis A1 and the second rotation axis A2, and the straight line LN includes the first rotation axis A1 and the lower arm rotation axis AL. It represents a plane. In this state, the annular rubber-like elastic member 13 is designed so that the tension when the rubber-like elastic member 13 is wound around the proximal pulley 11 and the distal pulley 12 becomes a predetermined tension.

The cross-sectional shape of the annular rubber-like elastic member 13 may be any shape, and is circular here. Here, the “rubber-like elastic member” means a member made of a polymer compound having elasticity. The “polymer compound having elasticity” includes natural rubber and synthetic rubber. The rubber-like elastic member 13 preferably has an elastic modulus within a range of 1 MPa or more and 10 MPa or less. Examples of the material of the rubber-like elastic member 13 include silicon rubber, fluororubber, nitrile rubber (NBR), hydrogenated nitrile rubber (HNBR) and the like.

The proximal pulley 11 and the distal pulley 12 are provided with a plurality of first guide grooves and a second guide groove, respectively, and a plurality of rubber-like elastic members are provided in the first guide groove and the second guide groove, respectively. The member 13 may be wound around.

In addition, the first guide groove 21 and the second guide groove 31 are each left as one and are formed deeper than usual, and the first guide groove 21 and the second guide groove 31 have a plurality of annular rubber-like elasticity. The member 13 may be overlapped and wound. Thereby, a plurality of rubber-like elastic members 13 can be used without increasing the number of guide grooves.

[motion]
Next, the operation of the articulated robot 100 configured as above will be described. FIG. 3 is a side view schematically showing a state in which the arm section 3 of the articulated robot 100 of FIG. 1 is rotated about the lower arm rotation axis AL.

Referring to FIGS. 1 and 3, in the balancer 14, as described above, the straight line LV connecting the first rotation axis A1 and the second rotation axis A2 when viewed from the extending direction of the lower arm rotation axis AL. When the angle θ at which the (hereinafter, simply referred to as the straight line LV) intersects the straight line LN (hereinafter, simply referred to as the straight line LN) connecting the first rotation axis A1 and the lower arm rotation axis AL is zero degrees, the first time The distance between the moving axis A1 and the second rotation axis A2 is minimized, which minimizes the tension of the annular rubber-like elastic member 13. The angular position of the balancer 14 in this state is called a "reference angular position". Further, the angle θ is referred to as a “rotation angle θ”.

The relationship between the rotation angle θ of the balancer 14 and the gravity counter moment generated by the balancer 14 on the arm portion 3 is the same as that of a general balancer. First, this will be briefly described.

When the arm unit 3 rotates from the standing state to the right or left in the figure around the lower arm rotation axis AL, the balancer 14 rotates upward or downward from the reference angle position around the first rotation axis A1. To do. Then, the rubber-like elastic member 13 expands, and a gravity counter moment according to the turning angle θ of the balancer 14 is generated in the lower arm portion 3a.

Next, the operation specific to the balancer 14 of this embodiment will be described. Hereinafter, the case where the arm unit 3 rotates to the right in the drawing will be described, but the same applies to the case where the arm unit 3 rotates to the left in the drawing, and the description thereof will be omitted.

When the arm portion 3 rotates from the standing state in FIG. 1 to the right in these figures around the lower arm rotation axis AL as shown in FIG. 3, the balancer 14 (specifically, the rubber-like elastic member). 13) rotates upward from the reference angular position around the first rotation axis A1. At this time, in the balancer 14, the distal pulley 12 rotates the proximal pulley 11 through the rubber-like elastic member 13 around the first rotation axis A1 in the same rotation direction as the balancer 14, and The side pulley 11 rotates the tip side pulley 12 through the rubber-like elastic member 13 around the second rotation axis A2 in the rotation direction opposite to the balancer 14. This prevents the rubber-like elastic member 13 wound around the proximal pulley 11 and the distal pulley 12 from being bent by the rotation of the arm 3. At this time, stresses in opposite directions are relatively generated in the pair of portions of the rubber-like elastic member 13 located between the pair of pulleys 11 and 12. Balanced by movement. Further, for example, assuming that the rubber-like elastic member 13 is formed in a rod shape, the rubber-like elastic member expands and contracts according to the rotation of the balancer to change the cross-sectional area (cross-sectional shape). It is difficult to firmly hold the rubber-like elastic member. However, in this embodiment, the rubber-like elastic member 13 is held by the pair of pulleys 11 and 12 at both ends of the balancer 14, so that the rubber-like elastic member 13 expands and contracts in accordance with the rotation of the balancer 14. Even if the (sectional shape) changes, the rubber-like elastic member 13 can be firmly held by the pair of pulleys 11 and 12 at both ends of the balancer 14.

Moreover, since the base end side pulley 11 and the tip end side pulley 12 are fixed to the swivel part 2 and the lower arm part 3a via the first bearing 23 and the second bearing 33, respectively, the base end side pulley 11 and the tip end side pulley 12 are The side pulleys 12 are fixed with play in their respective axial directions. Therefore, when the arm portion 3 rotates, the proximal pulley 11 and the distal pulley 12 move in their respective axial directions, so that the proximal pulley 11 and the distal pulley 12 of the rubber-like elastic member 13 are separated. The axial misalignment is automatically corrected.

Furthermore, when a plurality of rubber-like elastic members 13 are used, by adjusting the number of rubber-like elastic members 13, the gravity counter moment by the balancer 14 can be easily adjusted. For example, there is a case where it is desired to adjust the gravity counter moment by the balancer 14 according to the weight of the work handled by the articulated robot 200. According to the present configuration example, it is possible to easily meet such a demand by adjusting the number of the rubber-like elastic members 13.

Further, when one of the plurality of rubber-like elastic members 13 is cut, the function of the balancer 14 can be maintained to some extent by the remaining rubber-like elastic members 13, and the cut rubber-like elastic members 13 are normal. The balancer 14 can be immediately returned to the normal state by replacing the balancer 14 with the above.

{Modification 1}
In the first modification of the first embodiment, the plurality of annular rubber-like elastic members 13 have different elastic coefficients.

According to this modified example 1, by appropriately selecting the elastic coefficient of the rubber-like elastic member 13, the gravity counter moment by the balancer 14 can be precisely adjusted.

(Embodiment 2)
FIG. 4 is a side view schematically showing an example of the configuration of the articulated robot 200 according to the second embodiment of the present invention. FIG. 5 is a side view schematically showing another example of the configuration of the articulated robot 200 according to the second embodiment of the present invention. 4 and 5, the detailed structure of the base portion and each link of the articulated robot 200 is omitted.

The multi-joint robot 200 of the second exemplary embodiment is different from the multi-joint robot 100 of the first exemplary embodiment in that the balancer 14 includes a tension adjusting pulley 15, and the other configurations are the same as those of the multi-joint robot 100 of the first exemplary embodiment. Hereinafter, this difference will be described.

Referring to FIG. 4, the revolving unit 2 is provided with a tension adjusting pulley 15 which is rotatable about a third rotation axis A3 parallel to the lower arm rotation axis AL. The tension adjusting pulley 15 is a pair of linear members positioned between the proximal pulley 11 and the distal pulley 12 of the annular rubber-like elastic member 13 wound around the proximal pulley 11 and the distal pulley 12. By adjusting at least one linear portion 13a, 13b of the portions 13a, 13b to be bent when viewed from the extending direction of the lower arm rotation axis AL, the position in the direction intersecting with the one linear portion 13a, 13b is adjusted It is provided so that it can be done.

Specifically, the tension adjusting pulley 15 has the same structure as the base end side pulley 11. Specifically, the tension adjusting pulley 15 includes an annular third guide groove (not shown) around which the rubber-like elastic member 13 is wound, a third rotary shaft insertion hole (not shown), and a third bearing. (Not shown). The third guide groove is provided coaxially with the third rotation shaft insertion hole. The third guide groove is formed such that one or more rubber-like elastic members 13 are wound in parallel. Here, the first guide groove is formed so that three rubber-like elastic members 13 are wound in parallel.

A third bearing is provided on the inner peripheral surface of the third rotary shaft insertion hole. On the other hand, the swivel unit 2 is provided with a third rotation shaft (not shown) coaxially with the third rotation axis A3. The tension adjusting pulley 15 is fitted to the third rotating shaft so that the third rotating shaft is inserted into the third rotating shaft insertion hole. After this fitting, a regulation member (not shown) is attached to the tip of the third rotation shaft, and the tension adjustment pulley 15 is regulated so as not to come off the third rotation shaft. With this configuration, the tension adjusting pulley 15 is rotatably fixed to the swivel unit 2 about the third rotation axis A3 via the third bearing and the third rotation shaft.

In one configuration example, the tension adjusting pulley 15 is located between the proximal pulley 11 and the distal pulley 12 of the annular rubber-like elastic member 13 wound around the proximal pulley 11 and the distal pulley 12. It is located above the upper linear portion 13a, and is arranged to bend the linear portion 13a downward. The tension adjusting pulley 15 is attached to the revolving unit 2 so as to be vertically movable via a movable mechanism (not shown). Accordingly, when the tension adjusting pulley 15 is moved downward, the tension of the rubber-like elastic member 13 is increased, and when the tension adjusting pulley 15 is moved upward, the tension of the rubber-like elastic member 13 is decreased.

Referring to FIG. 5, in another configuration example, the tension adjusting pulley 15 includes a proximal end pulley 11 and a distal end side of an annular rubber-like elastic member 13 wound around the proximal end pulley 11 and the distal end pulley 12. It is located below the upper linear portion 13 a located between the pulley 12 and the upper linear portion 13 a so as to bend the linear portion 13 a upward. The tension adjusting pulley 15 is attached to the revolving unit 2 so as to be vertically movable via a movable mechanism (not shown). Accordingly, when the tension adjusting pulley 15 is moved upward, the tension of the rubber-like elastic member 13 is increased, and when the tension adjusting pulley 15 is moved downward, the tension of the rubber-like elastic member 13 is decreased.

It should be noted that the tension adjusting pulley 15 is located on the lower side between the proximal pulley 11 and the distal pulley 12 of the annular rubber-like elastic member 13 wound around the proximal pulley 11 and the distal pulley 12. The linear portion 13b may be arranged so as to be bent.

Further, the tension adjusting pulley 15 may be provided on the lower arm portion 3a as in the above.

According to the second embodiment as described above, by adjusting the position of the tension adjusting pulley 15 in the direction intersecting with the one linear portion 13a, 13b, the bending degree of the one linear portion 13a, 13b is adjusted. Therefore, the tension of the rubber-like elastic member 13 can be adjusted.

The following cases can be mentioned as cases where the articulated robot 200 of the second embodiment has a remarkable effect. For example, the rubber-like elastic member 13 expands due to aging, and the tension decreases. In such a case, the tension of the rubber-like elastic member 13 can be returned to a predetermined tension by adjusting the position of the tension adjusting pulley 15.

(Embodiment 3)
FIG. 6 is a side view schematically showing an example of the configuration of an articulated robot according to Embodiment 3 of the present invention. FIG. 7 is a side view schematically showing a state in which the arm part of the articulated robot of FIG. 6 is rotated about the lower arm rotation axis. 6 and 7, the detailed structure of the base portion and each link of the articulated robot 300 is omitted.

The multi-joint robot 300 of the third exemplary embodiment is different from the multi-joint robot 100 of the first exemplary embodiment in that the balancer 14 includes the intermediate pulley 16, and the other configurations are the same as those of the multi-joint robot 100 of the first exemplary embodiment. Hereinafter, this difference will be described.

Referring to FIGS. 6 and 7, the revolving unit 2 is provided with an intermediate pulley 16 rotatably around a fourth rotation axis A4 parallel to the lower arm rotation axis AL. The intermediate pulley 16 is a pair of linear portions located between the proximal pulley 11 and the distal pulley 12 of the annular rubber-like elastic member 13 wound around the proximal pulley 11 and the distal pulley 12. The portions 13a and 13b are provided so as to be bent when viewed from the extending direction of the lower arm rotation axis AL (see particularly FIG. 7).

The configuration of the intermediate pulley 16 is the same as that of the tension adjusting pulley 15 of the second embodiment, except that the intermediate pulley 16 is fixed to the swivel unit 2, and thus the description thereof will be omitted.

The intermediate pulley 16 has a pair of linear portions 13a and 13b located between the proximal pulley 11 and the distal pulley 12 of the rubber elastic member 13 in the extending direction of the lower arm rotation axis AL. Although it is provided so as to be bent upward as viewed from above, the pair of linear portions 13a and 13b may be provided so as to be bent downward.

Referring to FIG. 7, according to the third embodiment, the annular rubber-like elastic member 13 wound around the proximal pulley 11 and the distal pulley 12 is attached to the lower arm rotation axis AL in the extending direction. Since it can be bent when viewed from above, the virtual position of the rubber-like elastic member 13 (indicated by a dotted line in FIG. 7) and the bent rubber-like elastic member 13 when the rubber-like elastic member 13 is assumed not to be bent It is possible to avoid interference with other members located in the space therebetween.

Further, as an important effect, according to the third embodiment, when the lower arm portion 3a rotates around the lower arm rotation axis AL, the balancer 14 rotates in the bending direction of the rubber elastic member 13. The state where the rubber-like elastic member 13 does not contact the intermediate pulley 16 may occur. On the other hand, when the balancer 14 rotates in the direction opposite to the bending direction of the rubber-like elastic member 13, the intermediate pulley 16 causes the rubber-like elastic member 13 to be bent more greatly. The gravity counter moment by the balancer 14 in the latter state is larger than the gravity counter moment by the balancer 14 in the former state. Therefore, according to the third embodiment, the balancer 14 can generate an asymmetric gravity counter moment in the lower arm portion 3a depending on the rotation direction of the lower arm portion 3a.

(Embodiment 4)
FIG. 8 is a side view schematically showing an example of the configuration of the articulated robot 400 according to the fourth embodiment of the present invention. In FIG. 8, the illustration of the detailed structure of the base portion and each link of the articulated robot 400 is omitted.

Referring to FIG. 8, the multi-joint robot 400 of the fourth embodiment is different from the multi-joint robot 100 of the first embodiment in that a balancer 44 is provided between the lower arm portion 3a and the upper arm portion 3b. The other configurations are the same as those of the articulated robot 100 of the first embodiment.

In the robot arm 4, the lower end portion of the upper arm portion 3b is rotatably connected to the lower arm portion 3a around a predetermined upper arm rotation axis AU. The upper arm rotation axis AU extends, for example, so as to pass through the central portion of the base end portion of the upper arm portion 3b in the direction perpendicular to the turning axis AS (here, the horizontal direction). The upper arm rotation axis AU is parallel to the lower arm rotation axis AL here.

The balancer 44 is the same as the balancer 14 except that the installation position is different. Specifically, the balancer 44 includes a proximal end pulley 41, a distal end pulley 42, and an annular rubber-like elastic member 43. The arrangement of the proximal pulley 41 and the distal pulley 42 will be described below, but this is an example, and the arrangement of the proximal pulley 41 and the distal pulley 42 may be appropriately changed according to the design of the articulated robot 400. , Designed.

The proximal pulley 41 is provided on the lower arm portion 3a so as to be rotatable about a fifth rotation axis A5 that is parallel to the upper arm rotation axis AU.

The front end pulley 42 is provided on the upper arm portion 3b so as to be rotatable about a seventh rotation axis A7 that is parallel to the upper arm rotation axis AU. The distal end pulley 42 is provided, for example, such that the seventh rotation axis A7 is located on the opposite side of the upper arm rotation axis AU from the upper arm portion 3b and away from the upper arm rotation axis AU.

The configurations of the proximal pulley 41 and the distal pulley 42 are the same as the configurations of the proximal pulley 11 and the distal pulley 12 of the first embodiment, so description thereof will be omitted.

According to the fourth embodiment as described above, a gravity counter moment can be generated in the upper arm portion 3b.

(Embodiment 5)
FIG. 9 is a side view schematically showing an example of the configuration of the articulated robot 500 according to the fifth embodiment of the present invention. In FIG. 9, the detailed structure of the base portion and each link of the articulated robot 500 is omitted.

Referring to FIG. 9, the multi-joint robot 500 according to the fifth embodiment is different from the multi-joint robot 300 according to the third embodiment in that a balancer 44 is provided between the lower arm portion 3a and the upper arm portion 3b. The other configurations are the same as those of the articulated robot 300 of the third embodiment. Regarding the balancer 44, the arrangement and configuration of the base end side pulley 41 and the tip end side pulley 41 are the same as those of the balancer 44 of the fourth embodiment, and the intermediate pulley 46 is arranged on the lower arm portion 3a. The configuration of the intermediate pulley 46 is the same as the configuration of the intermediate pulley 16 of the third embodiment.

According to the fifth embodiment as described above, a gravity counter moment can be generated in the upper arm portion 3b. Also, avoiding interference with other members located in the space between the virtual position of the rubber-like elastic member 43 and the bent rubber-like elastic member 43, assuming that the rubber-like elastic member 43 is not bent. You can Furthermore, depending on the rotation direction of the upper arm 3b, the balancer 44 can generate an asymmetric gravity counter moment on the upper arm 3b.

(Embodiment 6)
Referring to FIG. 1, a multi-joint robot according to a sixth exemplary embodiment of the present invention is similar to the multi-joint robots 100 to 500 of the first to fifth exemplary embodiments in that the balancer 14 and the balancer 44 are covered by a cover member (not shown). It has been modified to.

According to the sixth embodiment, the balancer 14 and the balancer 44 can be protected.

(Other embodiments)
In each of the above-described embodiments and the first modification of the first embodiment, the size, shape, and installation position of each pulley 11, 12, 15, 16, 41, 42, 46 are determined according to the specifications of the articulated robots 100 to 500. , Designed as appropriate.

In any of the first to sixth embodiments, only the balancer 44 may be provided without providing the balancer 14.

Many modifications and other embodiments will be apparent to those skilled in the art from the above description. Therefore, the above description should be construed as exemplary only.

INDUSTRIAL APPLICABILITY The other joint robot of the present invention is useful as a multi-joint robot provided with a balancer that does not cause outgassing and can suppress the size increase of the robot.

1 Base 2 Swivel 3 Arm 3a Lower arm 3b Upper arm 11,41 Base side pulley 12,42 Tip side pulley 13,43 Rubber-like elastic member 14,44 Balancer 15 Tension adjustment pulley 16,46 Intermediate pulley 21 1 guide groove 22 1st rotation shaft insertion hole 23 1st bearing 25 1st rotation shaft 26 regulation member 31 2nd guide groove 32 2nd rotation shaft insertion hole 33 2nd bearing 35 3rd rotation shaft 36 regulation member 100,200, 300, 400, 500 Articulated robot AS Turning axis AL Lower arm turning axis AU Upper arm turning axis A1 to A7 First to seventh turning axis θ Turning angle

Claims (8)

A robot arm including a plurality of links and one or more joints that connect a pair of adjacent links of the plurality of links so as to be relatively rotatable about respective rotation axes.
A tip of the pair of links is provided between a pair of links that are rotatably connected to each other by a joint having a predetermined rotation axis of the one or more joints. A balancer for generating a moment against the load moment around the predetermined rotation axis due to the weight of the robot arm on the tip side link close to
A first pulley provided on a base end side link remote from a tip end of the pair of links, wherein the balancer is rotatable about a first pivot axis parallel to the predetermined pivot axis; A second pulley provided on the distal end side link so as to be rotatable around a second rotation axis parallel to a predetermined rotation axis, and an annular shape wound around the first pulley and the second pulley. A multi-joint robot including a rubber-like elastic member. The robot arm has a base portion which is the link fixed to an object to be fixed, a swing portion which is the proximal end link which is rotatably connected to the base portion around a swing axis, and the predetermined rotation. A lower arm portion which is an axial line and is the distal end side link rotatably connected to the turning portion about a lower arm turning axis which is perpendicular to the turning axis;
The balancer is provided between the swivel portion and the lower arm portion, and generates a moment against the load moment around the lower arm rotation axis due to the weight of the robot arm in the lower arm portion. ,
The first pulley is provided on the revolving unit so as to be rotatable about the first rotation axis parallel to the lower arm rotation axis.
The multi-joint robot according to claim 1, wherein the second pulley is provided on the lower arm portion so as to be rotatable around the second rotation axis parallel to the lower arm rotation axis. The robot arm has a base portion that is the link fixed to a fixed object, a swing portion that is the link that is rotatably connected to the base portion around a swing axis, and a lower arm that is perpendicular to the swing axis. A lower arm portion that is the proximal end link that is rotatably connected to the turning portion around a turning axis, and an upper arm turning axis that is the predetermined turning axis and is perpendicular to the turning axis. An upper arm portion that is the tip side link rotatably connected to the lower arm portion,
The balancer is provided between the lower arm portion and the upper arm portion, and causes the upper arm portion to generate a moment against the load moment around the upper arm rotation axis due to the weight of the robot arm.
The first pulley is provided on the lower arm portion so as to be rotatable around the first rotation axis parallel to the upper arm rotation axis, and the second pulley is parallel to the upper arm rotation axis. The articulated robot according to claim 1 or 2, wherein the articulated robot is provided on the upper arm so as to be rotatable around the second rotation axis. The articulated robot according to any one of claims 1 to 3, wherein a plurality of the annular rubber-like elastic members are wound around the first pulley and the second pulley. The articulated robot according to claim 4, wherein the plurality of annular rubber-like elastic members have elastic coefficients different from each other. A tension adjusting pulley is provided on the base end side link or the tip end side link so as to be rotatable about a third rotation axis parallel to the predetermined rotation axis, and the tension adjustment pulley includes the tension adjustment pulley. At least one linear portion of the annular rubber-like elastic member wound around the first pulley and the second pulley is located between the first pulley and the second pulley, and The multi-element according to any one of claims 1 to 5, which is provided so as to be bent when viewed from the extending direction so that the position in the direction intersecting with the one linear portion can be adjusted. Joint robot. An intermediate pulley is provided on the base end side link so as to be rotatable about a fourth rotation axis parallel to the predetermined rotation axis, and the intermediate pulley includes the first pulley and the second pulley. A pair of linear portions positioned between the first pulley and the second pulley of the annular rubber-like elastic member wound around and viewed from the extending direction of the predetermined rotation axis, The articulated robot according to any one of claims 1 to 5, which is provided so as to be bent. The articulated robot according to claim 1, wherein the balancer is covered with a cover member.

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