JP2000130534A - Joint mechanism in parallel link mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a joint mechanism capable of forming the size of a fixed plate or a moving late of a parallel link mechanism compact, and reducing the total height of the mechanism. SOLUTION: This joint mechanism has a first intermediate member 71 provided with two parallel first shafts 73 for rotatably journalling link members 3, 3. A second shaft 72 orthogonal to the first shafts 73 is provided at the first intermediate member 71. A third shaft 75 provided in a second intermediate member 72 rotatably journalling the second shaft 72 is rotatably journalled to a bearing member 76 provided at a moving plate 2. The first, second and third shafts are orthogonal each other. Since the link members 3 are respectively journalled to the separated parallel first shafts, ball screws of the link members do not interfere with each other in the neighborhood of the first shafts 73. Thus, the total height of a parallel link mechanism can be reduced. Further, since compact joints are obtained, and the parallel link mechanism can be formed compact.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an industrial robot,
Drilling of deburring devices, machining centers, drills, etc.
The present invention relates to a parallel link mechanism used for a YAG laser beam machine or the like that performs drilling or welding on a thin plate, and particularly to a joint mechanism used for the parallel link mechanism.

[0002]

2. Description of the Related Art In a parallel link mechanism, a first member and a second member spaced from the first member are connected by a plurality of link members, and one of the first and second members is connected. The other is a fixed plate, and the other is a movable plate. An end effector, a tool, or the like is attached to the movable plate, and a link member is driven to change the position and posture of the movable plate to perform work.

[0003] In this parallel link mechanism, as shown in FIG. 3, six link members 3 are connected to each other by joints 4 provided at six places on a fixed plate 1 and a movable plate 2, and the link of each link member 3 is connected. By coordinating the changes in length,
The position and posture of the moving plate 2 are changed. Although this joint has two degrees of freedom and three degrees of freedom, its rotation axis often intersects at one point, and has two gimbal axes and a gimbal +
A rotating three-axis or spherical bearing is used.

In the case of a parallel link mechanism as shown in FIG. 3 in which the fixed plate 1 and the movable plate 2 are connected at six locations with six link members, joints connecting the link members occupy six locations. The moving plate 2 becomes large, and a compact parallel link mechanism cannot be obtained.

Therefore, the link member is connected to the moving plate 2 by two.
A parallel link mechanism that is combined with the moving plate at three places as described above so that the moving plate 2 can be made smaller is also known.
FIG. 2 is an example of a joint 110 for attaching such two link members to the moving plate 2 collectively.

The joint 110 has two link members 100, 1
00, and link members 100, 1
00 are connected to a first shaft 112 provided on a first member 111 of the joint 110.
Are rotatably supported. Also, the first member 111 of the joint 110 has a second shaft 11 orthogonal to the first shaft.
The second shaft 113 is rotatably supported by a second member 114. Further, the second member 114 has a third axis 115 orthogonal to the second axis 113,
The third shaft 115 is rotatably supported by the movable plate 2. As a result, the joint 110 becomes a joint having three degrees of freedom, and the moving plate 2 connects the two link members 100 at three places by the joint 110.

When the link member is of an extendable type, as shown in FIG. 2, the connecting member 102 is fixed to the tip of a tube 101, and the link length of the link members 100, 100 is expanded and contracted in the tube 101. Ball screw 103 is inserted. The ball screw 103 is screwed with a ball nut (not shown) fixed to the tube 101, and the ball screw is driven and rotated by a servo motor (not shown), whereby the ball nut, the tube 101, and the connecting member 102 are connected.
Is moved linearly to extend or shorten the link length.

[0008]

In a joint for linking two link members together, if the link member is of an extendable type as described above, the length of the ball screw 103 is set to maximize the extension and contraction of the link length. As long as possible.
Therefore, when the link length is minimized, the ball screw 103
Project to the connection member 102.

However, the two link members 100, 100
Is axially mounted on the common first shaft 112 of the common joint 110, the extension of the ball screw 103 of the two link members 100, 100 intersects at the position of the first shaft 112. As a result, the two link members 100, 1
When 00 is reduced, the tips of the ball screws 103 interfere with each other. In order to prevent this interference, the link members 10 are arranged so that the two ball screws do not interfere even when the two link members 100, 100 are reduced to the minimum.
The distance between the position of the tip end surface of the ball screw and the first shaft 112 when 0 is reduced to the minimum may be long. However, if the distance between them is increased, there is a disadvantage that the overall height of the parallel link mechanism increases accordingly.

In this case, if the two link members are not supported by one shaft but supported by two shafts, the above problem can be solved. For example, in FIG. 2, two first shafts 112 may be provided in parallel with the first member 111, and the link members may be supported on the respective shafts.
11 increases, and as the size of the first member 111 increases, the size of the second member 114 also increases. As a result, the joint portion becomes large, the moving plate 2 becomes large, and the parallel link mechanism cannot be formed compactly.

Therefore, an object of the present invention is to provide a joint for attaching two link members used in a parallel link mechanism collectively, wherein the size of a fixed plate or a moving plate can be made compact and the parallel link can be formed. An object of the present invention is to provide a joint mechanism capable of reducing the overall height of the mechanism.

[0012]

A first member and a second member arranged at a distance from the first member are connected by a plurality of link members, and two or more links of the plurality of link members are provided. In a joint mechanism in a parallel link mechanism that supports members collectively on the first member or the second member, the present invention includes first axes parallel to each other that rotatably support two or more link members. A first intermediate member having a second axis orthogonal to the first axes parallel to each other and not in a plane formed by the first axes; and the second axis is rotatable. And a second intermediate member having a third axis orthogonal to the second axis, and the third axis is rotatably supported by the first member or the second member. The joint mechanism of the parallel link mechanism is formed.

[0013]

FIG. 1 is a schematic perspective view of a parallel link mechanism to which a joint mechanism according to the present invention is applied. Fixing plate 1
And the moving plate 2 are connected by six link members 3.
Each link member 3 is connected to the fixed plate 1 by a conventional joint 6 having two degrees of freedom. Two link members 3 are connected to the movable plate 2 in pairs by a joint 7 of the present invention provided at a position equidistant from each other.

The link member 3 includes a pipe 31 and a pipe 32,
It is separated by a bellows part 35. A ball nut (located in bellows 35, not visible in FIG. 1) at the lower end of upper tube 32
Is fixed. The inner diameter of the lower tube 31 is
And the outer diameter of the ball nut fixed to the tube 32. A ball screw penetrates through the tubes 31 and 32, and the ball screw and the ball nut are screwed together.

The ball screw is driven by the servomotor M via the transmission mechanism 5, and as a result, the upper tube 32 is moved linearly along the ball screw. A connecting member 34 for connecting to the joint 7 is fixed to the upper pipe 32.

The joint 7 has two first shafts 7 parallel to each other.
3,73 and the two parallel first axes 7
A first intermediate member 71 having a second shaft 74 orthogonal to the first and third members 73 and projecting above the plane of the two first shafts parallel to each other.
Having. Furthermore, the second shaft 7 of the first intermediate member 71
And a second intermediate member 72 rotatably supporting the fourth member 4, and the second intermediate member 72 is orthogonal to the second shaft 74 and the two first shafts 73 parallel to each other and moves. It has a third axis 75 parallel to the plane of the plate 2. The third shaft 75 is rotatably supported by a bearing member 76 provided on the movable plate 2.

The connecting members 34, 34 fixed to the upper ends of the tubes 32 of the two link members 3, 3 are rotatable about two first shafts 73 disposed in parallel with each other. It is pivoted.

Although the bearing member 76 is formed integrally with the movable plate 2 in the example shown in FIG.
6 may be provided independently and this bearing may be fixed to the moving plate 2.

As described above, the joint 7 has the first, second, and third axes that are orthogonal to each other, and is formed to be rotatable about these axes. Is rotated, the ball nut screwed into the ball screw moves linearly to expand and contract the link member 3. By expanding and contracting the six link members 3 in cooperation,
The desired position and posture can be controlled while rotating the movable plate 2 around the first, second, and third axes orthogonal to each joint 7.

In the present invention, the first shafts 73 for rotatably connecting the link members 3 are provided separately in parallel, and the link members 3 are rotatably attached to the first shafts 73, respectively. When the link members 3 and 3 are expanded and contracted, it is possible to prevent the tips of the ball screws of the link members 3 from interfering with each other. Therefore, the distance between the first shaft 73 and the end face of the ball screw when the link member 3 has the minimum link length can be made shorter than that of the conventional joint 110 shown in FIG. As a result, the overall height of the parallel link mechanism can be reduced, and a compact parallel link mechanism can be obtained.

Further, comparing the height of the joint 7 between FIG. 1 of the embodiment of the present invention and FIG. 2 of the conventional example, the first member 111 of the conventional joint 110 is the first intermediate member of the joint 7 of the embodiment of the present invention. The second member 114 of the conventional joint 110 corresponds to the second intermediate member 72 of the joint 7 of the present invention. However, in the conventional joint 110, the movable plate 2 is axially mounted on the second member 114. On the other hand, in the embodiment of the present invention, the moving plate 2 is attached at a position at substantially the same height as the second intermediate member 72. As a result, from this point as well, the overall height of the parallel link mechanism can be reduced, and a compact parallel link mechanism can be obtained.

The second intermediate member 72 may be pivotally attached to the lower surface of the movable plate 2 instead of being axially attached to the movable plate 2 (the bearing member 76 is provided on the lower surface of the movable plate 2). ,
In this case, the overall height of the parallel link mechanism is increased, but the plane of the movable plate 2 can be reduced.

In the above-described embodiment of the present invention, two parallel first shafts 73 are provided to connect different link members. However, when link members are further connected, the parallel first shafts 73 are connected. The axis of the increased first
What is necessary is just to rotatably support a new link member on the shaft.
Further, in the above embodiment, the example in which the joint of the present invention is applied to the moving plate is shown, but the moving plate may be applied to a fixed plate.

[0024]

According to the present invention, a compact joint mechanism is obtained as a joint for joining two or more link members together to the first member or the second member forming the fixed plate and the moving plate of the parallel link mechanism. By using this joint mechanism, the first member or the second member to which this joint is attached can be made compact. As a result, interference with a work or a jig during work is reduced, and work can be performed efficiently. Further, since the overall height of the parallel link mechanism can be reduced, a parallel link mechanism suitable for work in a narrower space can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view of an outline of a parallel link mechanism to which a joint mechanism of the present invention is applied.

FIG. 2 is a perspective view showing an example of a conventional joint mechanism.

FIG. 3 is an explanatory view of a conventional parallel link mechanism in which a fixed plate and a movable plate are connected to a link member at six locations.

[Explanation of symbols]

 Reference Signs List 1 fixed plate 2 moving plate 3 link member 4, 7, 110 joint 71 first intermediate member 72 second intermediate member 73 first shaft 74 second shaft 75 third shaft 76 bearing member M servo motor

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[Procedure amendment]

[Submission date] September 9, 1999 (1999.9.9)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction contents]

[Document Name] Statement

[Title of the Invention] Joint mechanism in parallel link mechanism

[Claims]

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an industrial robot,
Drilling of deburring devices, machining centers, drills, etc.
The present invention relates to a parallel link mechanism used for a YAG laser beam machine or the like that performs drilling or welding on a thin plate, and particularly to a joint mechanism used for the parallel link mechanism.

[0002]

2. Description of the Related Art In a parallel link mechanism, a first member and a second member spaced from the first member are connected by a plurality of link members, and one of the first and second members is connected. The other is a fixed plate, and the other is a movable plate. An end effector, a tool, or the like is attached to the movable plate, and a link member is driven to change the position and posture of the movable plate to perform work.

[0003] In this parallel link mechanism, as shown in FIG. 3, six link members 3 are connected to each other by joints 4 provided at six places on a fixed plate 1 and a movable plate 2, and the link of each link member 3 is connected. By coordinating the changes in length,
The position and posture of the moving plate 2 are changed. Although this joint has two degrees of freedom and three degrees of freedom, its rotation axis often intersects at one point, and has two gimbal axes and a gimbal +
A rotating three-axis or spherical bearing is used.

In the case of a parallel link mechanism as shown in FIG. 3 in which the fixed plate 1 and the movable plate 2 are connected at six locations with six link members, joints connecting the link members occupy six locations. The moving plate 2 becomes large, and a compact parallel link mechanism cannot be obtained.

Therefore, the link member is connected to the moving plate 2 by two.
A parallel link mechanism that is combined with the moving plate at three places as described above so that the moving plate 2 can be made smaller is also known.
FIG. 2 is an example of a joint 110 for attaching such two link members to the moving plate 2 collectively.

The joint 110 has two link members 100, 1
00, and link members 100, 1
00 are connected to a first shaft 112 provided on a first member 111 of the joint 110.
Are rotatably supported. Also, the first member 111 of the joint 110 has a second shaft 11 orthogonal to the first shaft.
The second shaft 113 is rotatably supported by a second member 114. Further, the second member 114 has a third axis 115 orthogonal to the second axis 113,
The third shaft 115 is rotatably supported by the movable plate 2. As a result, the joint 110 becomes a joint having three degrees of freedom, and the moving plate 2 connects the two link members 100 at three places by the joint 110.

When the link member is of an extendable type, as shown in FIG. 2, the connecting member 102 is fixed to the tip of a tube 101, and the link length of the link members 100, 100 is expanded and contracted in the tube 101. Ball screw 103 is inserted. The ball screw 103 is screwed with a ball nut (not shown) fixed to the tube 101, and the ball screw is driven and rotated by a servo motor (not shown), whereby the ball nut, the tube 101, and the connecting member 102 are connected.
Is moved linearly to extend or shorten the link length.

[0008]

In a joint for linking two link members together, if the link member is of an extendable type as described above, the length of the ball screw 103 is set to maximize the extension and contraction of the link length. As long as possible.
Therefore, when the link length is minimized, the ball screw 103
Project to the connection member 102.

However, the two link members 100, 100
Is axially mounted on the common first shaft 112 of the common joint 110, the extension of the ball screw 103 of the two link members 100, 100 intersects at the position of the first shaft 112. As a result, the two link members 100, 1
When 00 is reduced, the tips of the ball screws 103 interfere with each other. In order to prevent this interference, the link members 10 are arranged so that the two ball screws do not interfere even when the two link members 100, 100 are reduced to the minimum.
The distance between the position of the tip end surface of the ball screw and the first shaft 112 when 0 is reduced to the minimum may be long. However, if the distance between them is increased, there is a disadvantage that the overall height of the parallel link mechanism increases accordingly.

In this case, if the two link members are not supported by one shaft but supported by two shafts, the above problem can be solved. For example, in FIG. 2, two first shafts 112 may be provided in parallel with the first member 111, and the link members may be supported on the respective shafts.
11 increases, and as the size of the first member 111 increases, the size of the second member 114 also increases. As a result, the joint portion becomes large, the moving plate 2 becomes large, and the parallel link mechanism cannot be formed compactly.

SUMMARY OF THE INVENTION An object of the present invention is to provide a joint for attaching two link members used in a parallel link mechanism together, in which the size of a fixed member or a moving member can be reduced, and the parallel link can be formed. An object of the present invention is to provide a joint mechanism capable of reducing the overall height of the mechanism.

[0012]

A fixed member and a moving member are connected to each other.
And connected by a plurality of link members arranged in parallel between them.
By driving each of the plurality of link members.
Change the position and orientation of the moving member with respect to the
Links in parallel link mechanism
A fixed member or a moving member for connecting two or more link members among the members
In the joint mechanism for collectively supporting the present invention is provided with a first shaft element parallel to each other for supporting two or more link members rotatably respectively, each first shaft element
A first intermediate member having a second shaft element substantially perpendicular to a plane formed by the first intermediate member, and the second intermediate member rotatably supporting the second shaft element ;
And a second intermediate member having a third axis elements generally perpendicular to the longitudinal element of the second, third shaft element fixed member or mobile
The joint mechanism of the parallel link mechanism is formed so as to be rotatably supported by the member .

[0013]

FIG. 1 is a schematic perspective view of a parallel link mechanism to which a joint mechanism according to the present invention is applied. Fixing plate 1
And the moving plate 2 are connected by six link members 3.
Each link member 3 is connected to the fixed plate 1 by a conventional joint 6 having two degrees of freedom. Two link members 3 are connected to the movable plate 2 in pairs by a joint 7 of the present invention provided at a position equidistant from each other.

The link member 3 includes a pipe 31 and a pipe 32,
It is separated by a bellows part 35. A ball nut (located in bellows 35, not visible in FIG. 1) at the lower end of upper tube 32
Is fixed. The inner diameter of the lower tube 31 is
And the outer diameter of the ball nut fixed to the tube 32. A ball screw penetrates through the tubes 31 and 32, and the ball screw and the ball nut are screwed together.

The ball screw is driven by the servomotor M via the transmission mechanism 5, and as a result, the upper tube 32 is moved linearly along the ball screw. A connecting member 34 for connecting to the joint 7 is fixed to the upper pipe 32.

The joint 7, two parallel first axis principal mutually
Comprising a containing 73, 73 and orthogonal to the first shaft element 73, 73 parallel the two, the two first axis of the parallel
It has a first intermediate member 71 with a second shaft element 74 protruding above the plane of the element . Further, the first intermediate member 71
A second intermediate member 72 rotatably supporting the second shaft element 74, and the second intermediate member 72 is formed of a second shaft element 74 and two parallel first shafts. Element 7
Perpendicular to the 3,73, parallel third axis principal and the plane of the moving plate 2
The element 75 is provided. The third shaft element 75 is rotatably supported by a bearing member 76 provided on the movable plate 2.

The connecting members 34, 34 fixed to the upper ends of the tubes 32 of the two link members 3, 3 are rotatable about two first shaft elements 73 arranged in parallel with each other. It is pivoted on.

Although the bearing member 76 is formed integrally with the movable plate 2 in the example shown in FIG.
6 may be provided independently and this bearing may be fixed to the moving plate 2.

As described above, the joint 7 has the first, second, and third shaft elements orthogonal to each other and is formed so as to be rotatable around these axes. When the ball screw is rotated, the ball nut screwed into the ball screw moves linearly, and causes the link member 3 to expand and contract.
By moving the six link members 3 in coordination and expansion and contraction, the movable plate 2 is controlled to a desired position and posture while rotating around the first, second and third shaft elements orthogonal to each joint 7. can do.

In the present invention, the first shaft element 73 for rotatably connecting the link member 3 is provided separately in parallel,
Since the link members 3 are rotatably attached to the first shaft elements 73, respectively, it is possible to prevent the tips of the ball screws of the link members 3 from interfering with each other when the link members 3 and 3 are expanded and contracted. Therefore, when the link member 3 has the minimum link length, the distance between the first shaft element 73 and the end face of the ball screw can be made shorter than that of the conventional joint 110 shown in FIG. As a result, the overall height of the parallel link mechanism can be reduced, and a compact parallel link mechanism can be obtained.

Furthermore, the height of the joint 7, comparing Figure 1 with the conventional example 2 of <br/> embodiment of the present invention, the first member 111 of the conventional joint 110 embodiment of the present invention Fitting 7
Of the conventional joint 110 corresponding to the first intermediate member 71 of FIG.
The member 114 corresponds to the second intermediate member 72 of the joint 7 of the present invention. However, the conventional joint 110 is different from the second member 114.
The moving plate 2 is mounted on the shaft. On the other hand, in the embodiment of the present invention, the moving plate 2 is attached at a position at substantially the same height as the second intermediate member 72. As a result, from this point as well, the overall height of the parallel link mechanism can be reduced, and a compact parallel link mechanism can be obtained.

The second intermediate member 72 may be pivotally attached to the lower surface of the movable plate 2 instead of being axially attached to the movable plate 2 (the bearing member 76 is provided on the lower surface of the movable plate 2). ,
In this case, the overall height of the parallel link mechanism is increased, but the plane of the movable plate 2 can be reduced.

In the above-described embodiment of the present invention, two parallel first shaft elements 73 are provided to connect different link members. However, when link members are further connected, the parallel first shaft elements 73 are connected. the new link member may be pivotally supported to the increased increased first shaft element that a shaft element. Further, in the above-described embodiment, the example in which the joint of the present invention is applied to the moving plate is shown, but the moving plate may be applied to a fixed plate.

[0024]

According to the present invention, a compact joint mechanism can be obtained as a joint for connecting two or more link members together to a fixed member and a movable member formed by the fixed plate and the movable plate of the parallel link mechanism. By using this joint mechanism, a fixing member or a transfer
The moving member can be formed compact. As a result, interference with a work or a jig during work is reduced, and work can be performed efficiently. Further, since the overall height of the parallel link mechanism can be reduced, a parallel link mechanism suitable for work in a narrower space can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view of an outline of a parallel link mechanism to which a joint mechanism of the present invention is applied.

FIG. 2 is a perspective view showing an example of a conventional joint mechanism.

FIG. 3 is an explanatory view of a conventional parallel link mechanism in which a fixed plate and a movable plate are connected to a link member at six locations.

[Description of Signs] 1 Fixed plate 2 Moving plate 3 Link member 4, 7, 110 Joint 71 First intermediate member 72 Second intermediate member 73 First shaft element 74 Second shaft element 75 Third shaft element 76 Bearing Material M Servo motor

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Kuniyasu Matsumoto 3580 Kobaba, Oshino-mura, Oshino-mura, Minamitsuru-gun Yamanashi Prefecture Inside FANUC Co., Ltd. FANUC Corporation F-term (reference) 4E068 CE05

Claims (2)

[Claims] A first member and a second member spaced from the first member are connected by a plurality of link members, and two or more link members of the plurality of link members are connected to the first member. 1
A joint mechanism in a parallel link mechanism that supports the two or more link members rotatably, and includes a first axis that is parallel to each other and rotatably supports the two or more link members, and a first axis that is parallel to each other. A second axis that is orthogonal to the axis of and is not in the plane formed by each first axis.
A first intermediate member having a second shaft, and a second intermediate member rotatably supporting the second shaft and having a third shaft orthogonal to the second shaft.
An intermediate member, wherein the third shaft is rotatably supported by the first member or the second member. 2. The joint mechanism for a parallel link mechanism according to claim 1, wherein said third shaft is supported on substantially the same plane as a plane of said first member or said second member rotatably supported.