JPH07108483A - Robot arm - Google Patents

Abstract

PURPOSE:To reduce the maintenance cost by exchanging simply only the joint parts of a robot arm partially. CONSTITUTION:A pair of two arms 2 and 3 of a robot arm 1 connect swayable the ways of two belt form links 2a and 2b, and 3a and 3b, through the first joints 5 and 5 which consist of bearing units, respectively. The first joints 5 and 5 are installed allowable to mount and demount to links 2a and 2b, and 3a and 3b, with bolts 8 and 9. Consequently, the first joints 5 and 5 can be mounted and demounted to the links 2a and 2b, and 3a and 3b simply, by operating the bolts 8 and 9, and furthermore, the links 2a, 2b, 3a, and 3b are not hurt.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a robot arm, and more particularly to improvement of a joint portion connecting at least two links.

[0002]

2. Description of the Related Art Conventionally, as a joint part of a robot arm,
For example, JP-A-63-210416 and JP-A-5-6
As shown in Japanese Patent Publication No. 0143, a structure using two rolling bearings and a shaft is known. That is, in these conventional examples, one rolling bearing is fitted in each through hole provided at each one end of each of the two links, and both ends of one shaft are attached to the inner peripheral portions of both rolling bearings. The structure is such that the part is fitted inside.

By the way, in a robot arm for general industrial machines, the operating environment is almost always room temperature, and since the rolling bearing used in the joint can be lubricated with grease or the like, the rolling bearing in the joint can be used. For, it has a relatively long life and does not require frequent replacement.
For this reason, the structure of the joint part is, as described above, generally adopted in such a form that the rolling bearing is directly incorporated in the through hole of the link.

The structure of the joint portion of the robot arm for a general industrial machine with a long history is inherited as it is even in a special robot arm installed inside the chamber of a sputtering apparatus.

[0005]

In the special robot arm as described above, since it is necessary to keep the working space clean, the rolling bearings used in the robot arm mostly use solid lubricant and have a sealed structure. Although the device has been devised, the lubrication condition of the rolling bearing is likely to deteriorate in a short period of time due to the harsh environment where the chamber interior is vacuum and high temperature, and the positioning accuracy of the robot arm deteriorates. As it will adversely affect the movement,
It is necessary to replace the rolling bearing in a relatively short cycle.

To replace the rolling bearing, a new one is detached from the through hole of the link of the robot arm and a new one is attached. However, the work itself is troublesome and time-consuming, and the size of the through hole of the link rolls. It will change due to the attachment / detachment of the bearing, which may significantly reduce the positioning accuracy of the robot arm.
Conventionally, when the rolling bearing reaches the limit of use, the entire robot arm is replaced with a new one.
Maintenance costs are high.

Even in the case of a robot arm for a general industrial machine, the same as the above can be said when the rolling bearing of the joint portion needs to be replaced.

In view of such circumstances, it is an object of the present invention to make it possible to partially and easily replace only the joint portion of the robot arm and to reduce the maintenance cost.

[0009]

A robot arm according to the present invention comprises at least two links and a joint portion for swingably connecting each of these links, and each joint portion comprises each of the links. The bearing unit is detachably attached to one end via a detachment tool.

[0010]

In the above structure, when it is necessary to replace the bearing unit which is the joint, the attaching / detaching tool may be operated to attach / detach the joint consisting of the bearing unit to / from each link. In other words, in this replacement, the work is simplified by only operating the attachment / detachment tool, and the attachment / detachment action does not damage the link.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described based on the embodiments shown in FIGS. FIG. 1 is a perspective view of a robot arm according to an embodiment of the present invention, and FIG. 2 is a partially exploded perspective view of the robot arm. In the figure, 1 is the entire robot arm, and 2 and 3 are two. The pair of arms 4 is a transport table.

The arms 2 and 3 are swingably connected to each other in the middle of the two belt-shaped links 2a and 2b and 3a and 3b via the first joint portions 5 and 5 formed of a bearing unit. Link 2 on each free end side of arms 2 and 3
The end positions of a and 3a are aligned side by side and attached to the transport table 4 via the second joint parts 6 and 6 formed of bearing units, and the links 2b on the base end side of the arms 2 and 3 are 3b are attached to the drive motor 7 in such a manner that their end positions are aligned so as to be the same swing fulcrum. That is, the robot arm 1 is horizontally supported in a cantilevered state with respect to the drive motor 7, and the two two links 2 a, 2 b, 3 of the pair of arms 2, 3 are supported by the drive motor 7.
By swinging a and 3b symmetrically in the left-right direction as shown by the arrow A in FIG. 1 to change the length of the arms 2, 3 in the longitudinal direction, the transport table 4 is moved in the front-back direction as shown by the arrow B in FIG. It is designed to move back and forth. In short, the robot arm 1 is used to mount an object to be transferred (not shown) on the transfer table 4 and transfer it to an arbitrary position in the longitudinal direction.

FIG. 3 is a vertical sectional side view of the left half of the first joint portion 5. The first joint portion 5 is a U-shaped member 51 that is detachably connected to the links 2b and 3b on the base end side of the arms 2 and 3 via bolts 8, and the two U-shaped members 51 face each other. Two rolling bearings 52, 53 which are fitted and mounted coaxially in the through holes 51a, 51b of the tongue piece, respectively, and a hollow bearing rotatably supported by the U-shaped member 51 via the rolling bearings 52, 53. A shaft 54 and a strip-shaped projecting piece 55a which is externally fitted and fixed to a longitudinal intermediate portion of the shaft 54 and is detachably connected to the links 2a and 3a on the free ends of the arms 2 and 3 via bolts 9. A swinging member 55 having
The rolling bearings 52 and 53 are provided with a wave washer 56 that applies a preload. In addition, the two rolling bearings 52,
The inner end surface (side of the swinging member 55) of 53 is sealed by seal rings 57, 57 which also serve as spacers. Also, 59,
Reference numeral 59 is a retaining ring for the rolling bearings 52, 53. And
The U-shaped member 51 is provided with a plurality of bolts 8 in a state in which the recesses 2c and 3c at the tips of the links 2b and 3b on the base end side are positioned and fitted to the step portion 51c provided below the rear surface of the main body. Is screwed into the U-shaped member 51 from the outer surface side of the links 2b and 3b. In the swinging member 55, a plurality of bolts 9 are provided on the upper surface side of the links 2a, 3a in a state where the recesses 2d, 3d at one end of the free ends of the links 2a, 3a are positioned and fitted to the strip-shaped projecting piece 55a. Is screwed to the strip-shaped protrusion 55a of the swing member 55. These bolts 8, 9
Corresponds to the desorption tool in the claims.

FIG. 4 is a vertical sectional side view of the left half of the second joint portion 6. The second joint portion 6 has a cylindrical member 6 having an outward flange 61a that is detachably connected to the links 2a, 3a on the free ends of the arms 2, 3 via bolts 10.
1 and an inward flange 6 on the inner peripheral surface of the cylindrical member 61.
Two rolling bearings 62, 63 fitted and mounted side by side on both sides of 1b, and rotatably supported concentrically with the cylindrical member 61 via the rolling bearings 62, 63, and the bolt 11 on the transport table 4. Hollow shaft 64 connected via
And a wave washer 65 that applies a preload to the rolling bearings 62 and 63, and a seal ring 66 that also serves as a washer that seals the outer end surface of one rolling bearing 62.
The outer end surface of the other rolling bearing 63 is sealed by an outward flange 64a formed on the shaft end of the shaft 64. The cylindrical member 61 has the outer periphery thereof fitted into the through holes formed at the tips of the links 2a, 3a on the free end side of the arms 2, 3 so that the bolt 10 is connected to the bolt 10.
It is screwed from the lower surface side of a, 3a to the outward flange 61a of the cylindrical member 61.

By the way, such a robot arm 1
Is used in an environment of vacuum and high temperature (room temperature to 300 ° C.) such as in the chamber of a sputtering apparatus, the links 2a, 2b, 3a, 3b and the first,
It is preferable to select the following materials for the respective constituent elements of the second joint portions 5 and 6. That is, the links 2a, 2
b, 3a, 3b and U-shaped member 51, swing member 55,
The cylindrical member 61 is an aluminum alloy, the shafts 54 and 64, the nuts 54b and 64b, and the retaining ring 59 are SUS304. In addition, the rolling bearings 52, 53, 62 and 63 are angular type full ball bearings which are back-to-back, respectively.
The outer ring is made of SUS440C and the balls are made of silicon nitride as a ceramic and used without lubrication. If such a material is selected, the U-shaped members 51 of the first and second joint parts 5 and 6,
Oscillating member 55, cylindrical member 61 and rolling bearings 52, 5
Since the difference in the coefficient of linear expansion from that of Nos. 3, 62, 63 becomes large, it is considered that the preload on the rolling bearings 52, 53, 62, 63 changes depending on the environmental temperature. Corresponding to wave washer 5
6, 65, the preload on the rolling bearings 52, 53, 62, 63 can be kept substantially constant.

As described above, if the first joint portion 5 of the robot arm 1 is a unit which is connected to the links 2a, 2b, 3a, 3b by the bolts 8 and 9, the first joint portion 5 should be replaced at the time of replacement. Operates the bolts 8 and 9 so that only the first joint 5 is linked to the links 2a, 2b, 3a and 3b.
It suffices to remove it and replace it with a new one, and there is no need to replace the links 2a, 2b, 3a and 3b. Moreover, the links 2a, 2b, 3a, 3b are not damaged when the first joint 5 is attached or detached. In this way, as the first joint portion 5 using the rolling bearings 52, 53, a bearing unit preassembled and manufactured by a bearing manufacturer can be used, so that the original links 2a, 2b, 3a, 3b can be used. On the other hand, the movement of the robot arm 1 can be maintained in an appropriate state while being simply attached using the bolts 8 and 9. of course,
The same applies to the second joint section 6.

The present invention is not limited to the above embodiment. For example, the rolling bearing 5 of the first and second joint portions 5 and 6
2, 53, 62 and 63 may be replaced by a deep groove type ball bearing, various roller bearings, or a slide bearing. Further, the rolling bearings 52, 53, 62, 63 may be sealed by using various other seals. Further, in the above-mentioned embodiment, the bearing is used without lubrication (dry), but depending on the degree of vacuum and the ambient temperature, grease for vacuum or a soft metal film of silver ion plating, lead, gold, copper, etc., Is molybdenum disulfide (MoS ₂ )
The use of solid lubricants such as

[0018]

As described above, according to the present invention, since the joint portion of the robot arm is a bearing unit that can be freely attached to and detached from the link via the attaching / detaching tool, when the joint portion needs to be replaced. The joint part can be attached / detached to / from the link by a simple operation of operating the attachment / detachment tool, and the movement of the robot arm can be properly managed even after the replacement. Moreover, since the link is not damaged when the joint part is attached or detached, the original link can be used semipermanently, which eliminates waste, so that the maintenance cost can be significantly reduced.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of a robot arm of the present invention.

FIG. 2 is an exploded perspective view of the arm.

FIG. 3 is a vertical sectional side view of a left half of a first joint portion of the arm.

FIG. 4 is a vertical sectional side view of a left half of a second joint portion of the arm.

[Explanation of symbols]

 1 Robot arm 2,3 Arm 2a, 3a Free end side link 2b, 3b Base end side link 5 First joint part 8,9 Bolt

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kenji Yamamoto, 3-5-8 Minamisenba, Chuo-ku, Osaka City Koyo Seiko Co., Ltd. (72) Kazunori Hayashida 3-5-8, Minamisenba, Chuo-ku, Osaka Koyo Seiko Incorporated (72) Inventor Hiroyuki Yamakawa 2500 Hagien, Chigasaki, Kanagawa Japan Vacuum Technology Co., Ltd. (72) Inventor Yoji Inoue 2500 Hagien, Chigasaki City, Kanagawa Nihon Vacuum Technology Co., Ltd. (72) Inventor Koike Doshio 2500 Hagien, Chigasaki City, Kanagawa Japan Vacuum Technology Co., Ltd. (72) Inventor Tadashi Takematsu 2500 Hagien, Chigasaki City, Kanagawa Japan Vacuum Technology Co., Ltd.

Claims (1)

[Claims] 1. At least two links, and a joint portion for swingably connecting each of these links,
The robot arm is characterized in that the joint portion comprises a bearing unit that can be attached to and detached from each one end of each of the links via an attachment / detachment tool.