JP2012077768A - Joint part for manipulator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small joint part for a manipulator which is easy to assemble, reduces cost, and can perform manipulator operation with high accuracy.SOLUTION: The joint part for a manipulator includes: a joint shaft arranged on an end part of a base arm; a unit mounting hole formed on an end part of a rotation arm; and a bearing unit having a housing fitting to the unit mounting hole and a plurality of rolling bearings arranged inside the housing and rotatably supporting the rotation arm with respect to the joint shaft. A locking groove along a shaft direction is formed on an outer circumference surface of the housing. A locking groove having a same shape as the locking groove on the housing side is formed on the unit mounting hole of the rotation arm. A locking member is arranged between both of the locking grooves.

Description

  The present invention relates to a joint unit for a manipulator that rotatably connects a plurality of arms in a manipulator that mechanically performs an operation similar to a human finger.

In the processing line and assembly line of industrial machines, various robot arms are used for labor saving and automation.
A robot arm is a device in which a plurality of arms are connected via a joint, and a device incorporating a double-row rolling bearing as a component of the joint is known (for example, Patent Document 1).

  The rolling bearing incorporated in the joint portion of Patent Document 1 increases the thickness dimension of the inner ring and the outer ring by setting the ratio of the axial sectional width and the radial sectional height of the bearing to a predetermined value, and has high rigidity. High rotational accuracy, low torque, and low heat generation.

By the way, technical development of a manipulator that mechanically performs an operation similar to a human finger, not a large-sized device such as a robot arm, is also being performed. It is difficult to adopt a rolling bearing for a robot arm as it is.
That is, when the specifications of the rolling bearing of Patent Document 1 that increases the thickness dimension of the inner ring and the outer ring are applied, the rolling bearing for the manipulator becomes large, so that it is adopted for a manipulator joint that is required to be downsized. It is difficult.

  In view of this, the present applicant has provided a small manipulator having a joint portion for manipulator that rotatably connects a plurality of arms. This manipulator can mechanically perform an operation similar to a human finger (Patent Document 2).

  However, in Patent Document 2 by the present applicant, it is considered that the housing of the rolling bearing and the rotating arm are fixed by adhesion or press-fitting, but if a failure occurs in this manipulator joint bearing, Since it is difficult to remove the single bearing from the arm member and the entire arm is replaced, there is room for examination from the viewpoint of work efficiency and cost.

JP 2006-329420 A JP 2010-587 A

  Therefore, the present invention employs a rolling bearing that is easy to assemble, thereby improving work efficiency and reducing assembly cost, and a small-sized manipulator joint that can perform highly accurate manipulator operation. The purpose is to provide a department.

The above object is achieved by the following configuration.
(1) A joint part for a manipulator that connects ends of the base arm and the rotating arm and rotates the rotating arm with the end as a fulcrum, and a joint shaft disposed at the end of the base arm; , A unit mounting hole formed at the end of the rotating arm, a housing that fits into the unit mounting hole, and a double row that is disposed inside the housing and rotatably supports the rotating arm with respect to the joint shaft A bearing unit having a rolling bearing, and a locking groove extending in the axial direction is formed on the outer peripheral surface of the housing. The unit mounting hole of the rotating arm is locked on the housing side. The manipulator is characterized in that a locking groove having the same shape as the groove is formed, and the rotating arm and the housing are relatively unrotatable by a locking member disposed between the both locking grooves. For joints.
(2) The bearing unit further includes a shaft member that is fitted to the inner ring of the double row rolling bearing and is fixed on the joint shaft.
(3) The double-row rolling bearing has a plurality of rolling elements arranged so as to be freely rollable between the outer ring and the inner ring, and a plurality of pockets formed in the circumferential direction to hold the rolling elements in the pockets. And a predetermined amount of lubricant is placed between adjacent pockets of the cage.

  By fixing the rotating arm of the manipulator joint and the housing of the bearing with a locking member, the rotating arm and the housing can be easily assembled, the assembly cost can be reduced, and the arm It can operate with high accuracy.

The perspective view which shows the outline of the manipulator which has the joint part for manipulators concerning embodiment of this invention. Schematic which shows the joint part bearing unit of the manipulator of FIG. Schematic which shows the rotation arm of the manipulator of FIG. Sectional drawing which shows the principal part of a manipulator 2nd joint part. Explanatory drawing regarding the assembly procedure of the bearing unit and rotation arm of FIG.

  Hereinafter, each embodiment of the joint part for manipulators of this invention is described in detail, referring FIGS.

  As shown in FIG. 1, the manipulator 1 includes a hollow cylindrical first arm 2, a hollow cylindrical second arm 3 composed of a small diameter portion 3 a and a large diameter portion 3 b, one end side having a hollow cylindrical shape, A hollow cylindrical third arm 4 having a spherical end, a first joint 5 connecting one end of the first arm 2 and one end of the second arm 3, and the second arm 3 And a second joint 6 connecting the end and one end of the third arm 4. Below, between the 2nd arm 3 as a base arm and the 3rd arm 4 as a rotation arm is demonstrated.

  The second joint portion 6 connecting the second arm 3 and the third arm 4 is mounted on the bearing unit 7 shown in FIG. 2 and the rotation center position of the bearing unit 7, and is formed at one end of the second arm 3. The connecting screw (joint shaft) 9 disposed on the connecting plate 3c, the drive wire 8 for rotating the third arm 4 around the connecting screw via the bearing unit 7, and the bearing unit 7 up to a predetermined angle. And a driving force transmission device 18 for transmitting the rotating tensile force to the driving wire 8.

  As shown in FIG. 4, the bearing unit 7 is a component in which two ball bearings 10, a single housing 11, and a single shaft member 12 are integrated. The ball bearing 10 includes an outer ring 10a and an inner ring 10b, a plurality of balls 10c that are rotatably arranged between the raceway grooves of the outer ring 10a and the raceway grooves of the inner ring 10b, and an axial direction between the outer ring 10a and the inner ring 10b. An annular seal body 10d that closes both ends is provided.

The material of the outer ring 10a, the inner ring 10b, and the ball 10c is a bearing steel (eg, SUJ2, SUJ3, etc.) under standard use conditions. However, a stainless steel material (eg, SUS440C, etc.) that is a corrosion-resistant material is used depending on the use environment. Martensitic stainless steel materials, austenitic stainless steel materials such as SUS304, precipitation hardening stainless steel materials such as SUS630, etc., titanium alloys and ceramic materials (for example, Si ₃ N ₄ , SiC, Al ₂ O ₃ , ZrO _2, etc.) ) May be adopted.

  The housing 11 is a cylindrical member that internally fits the outer rings 10a of the two ball bearings 10 and that fits into the inner periphery of a unit mounting hole 13 of the third arm 4 described later shown in FIG. An annular convex portion 11a is provided along the circumferential direction at the axially central portion of the inner peripheral surface. A locking groove 11b (see FIG. 2) extending in the axial direction is formed on the outer peripheral surface.

  The shaft member 12 is a cylindrical member that fits into the inner peripheral portion of the inner ring 10b of the ball bearing 10, and has an inner peripheral surface formed with a female screw portion into which the connecting screw 9 (FIG. 4) is screwed. On the surface, a flange 12a (FIG. 4) is formed on one side in the axial direction so as to protrude toward the outer diameter side. In addition, although the collar part 12a does not necessarily need to be provided, the ball bearing 13 can be positioned by providing the collar part 12a.

  As the material of the second arm 3 and the third arm 4, a material having a larger linear expansion coefficient than the material of the outer ring 10a and the inner ring 10b of the bearing 10 is used. The connecting screw 9 is made of a material having a larger linear expansion coefficient than that of the shaft member 12. Thereby, even if the inner and outer rings 10b and 10a of the bearing 10 expand due to heat generated from the bearing 10 during operation, rigidity can be ensured.

  As shown in FIG. 3, the unit mounting hole 13 on the inner peripheral surface of the third arm 4 is formed to open in a circular shape in a direction orthogonal to the longitudinal direction of the third arm 4. The unit mounting hole 13 is formed with an axial locking groove 4a and has the same shape as the above-described locking groove 11b on the housing 11 side. The locking member 14 can be inserted between the locking grooves 4a and 11b.

Next, a method for assembling the second joint portion 6 configured as described above will be described with reference to FIGS.
First, with the annular protrusion 11 a interposed between the outer rings 10 a of the two bearings 10, each outer ring 10 a is bonded or press-fitted and fixed to the inner peripheral surface of the housing 11. And the bearing unit 7 is assembled. At this time, the inner ring 10 b of one bearing 10 abuts on the flange portion 12 a of the shaft member 12.
Then, the locking member 14 is inserted into the locking groove 11 b of the housing 11, and the locking member 14 and the locking groove 4 a are aligned with the unit mounting hole 13 of the third arm 4, and then inserted. To do. Alternatively, the locking member 11 may be inserted between the two locking grooves 4a and 11b by matching the positions of the locking groove 11b on the housing 11 side and the locking groove 4a on the third arm 4 side. . Thereby, the third arm 4 is fixed to the bearing unit 7 of the second arm.
Subsequently, as shown in FIG. 4, the third arm 4 is disposed between the connecting plates 3 c of the second arm 3 and the connecting screw 9 is tightened, whereby the connecting screw 9 is formed on the shaft member 12 of the bearing unit 7. The third arm 4 is fixed to the second arm 3 so as to be rotatable.

  In the present embodiment, the structure of the second joint portion 6 of the manipulator 1 has been described, but the first joint portion 5 may adopt the same structure as the second joint portion 6. For example, the first joint portion 5 is mounted at a rotation center position of the bearing unit 15 including two ball bearings 10 that are fitted into unit mounting holes formed in the small diameter portion 3 a of the second arm 3. The connecting screw 16 disposed on the connecting plate 2c formed at one end of the first arm 2 and the driving wire 17 for rotating the second arm 3 around the connecting screw 16 are provided. The driving force transmission device 18 is connected to the above-described driving force transmission device 18.

  In the present embodiment, the third arm 4 and the housing 11 of the bearing are stopped by the locking member, so that the second joint portion 6 can be easily assembled and the assembly cost can be reduced.

  Further, the bearing unit 7 is a member in which two ball bearings 10 are incorporated between a single housing 11 and a single shaft member 12, so that difficult mounting of the ball bearing 10 is not required when the manipulator 1 is assembled. Therefore, the assembly cost can be further reduced. Further, it is easy to replace the bearing 10 at the time of failure or maintenance.

1 Manipulator 2 First arm (base arm)
3 Second arm (base arm, pivot arm)
4 Third arm (rotating arm)
4a Locking groove 5 First joint (manipulator joint)
6 Second joint (manipulator joint)
7, 15 Bearing unit 10 Ball bearing (rolling bearing)
10a outer ring 10b inner ring 10c ball (rolling element)
DESCRIPTION OF SYMBOLS 11 Housing 11a Annular convex part 11b Locking groove | channel 12, 29 Shaft member 12a ridge part 14 Locking member 9, 16 Connecting screw 8, 17 Driving wire 18 Driving force transmission apparatus

Claims (3)

A joint part for a manipulator that connects ends of the base arm and the rotating arm and rotates the rotating arm with the end as a fulcrum,
A joint shaft disposed at the end of the base arm;
A unit mounting hole formed at the end of the rotating arm, a housing that fits into the unit mounting hole, and a rotating arm that is disposed inside the housing and is rotatably supported with respect to the joint shaft. A bearing unit having a double row rolling bearing
A locking groove along the axial direction is formed on the outer peripheral surface of the housing, and a locking groove having the same shape as the locking groove on the housing side is formed in the unit mounting hole of the rotating arm. The manipulator joint is characterized in that the rotating arm and the housing are relatively unrotatable by a locking member disposed between the locking grooves.   2. The joint part for manipulators according to claim 1, wherein the bearing unit further includes a shaft member fitted to an inner ring of the double row rolling bearing and fixed on the joint shaft.   The double-row rolling bearing includes a plurality of rolling elements that are rotatably arranged between an outer ring and an inner ring, and a cage that forms a plurality of pockets in the circumferential direction and holds the rolling elements in the pockets. The joint part for manipulators according to claim 1 or 2, further comprising a predetermined amount of lubricant placed between adjacent pockets of the cage.

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