JP2007187234A - Oil seal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an oil seal which resists coming off by increasing the coming-off pressure than before is, and hardly causes oil leakage, poor lubrication, and breakage in a reduction device. <P>SOLUTION: The oil seal 30 which prevents an outflow of lubricating oil in equipment includes a metal ring and a rubber lip covering the metal ring. A fitting part 30a to be fit to a housing is formed in the outside periphery of the lip covering the outside periphery of the metal ring. In the oil seal 30, the inside diameter part 30b on the tip end side of the metal ring is formed so as to be press-fit. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an oil seal. More specifically, the present invention relates to an oil seal for preventing outflow of lubricating oil such as oil and grease in a rotating device and preventing foreign matter from entering from the outside.

  Oil seals are widely used to prevent the outflow of lubricating oil in a rotating device such as a reduction gear and to prevent foreign substances from entering from outside.

  Generally, an oil seal is made of a metal ring and a rubber lip that covers the metal ring (see, for example, Non-Patent Document 1).

In the conventional oil seal, a fitting portion that is fitted to the housing is formed on the outer periphery of the lip that covers the outer peripheral portion of the metal ring, and this fitting portion is provided inside the device in which leakage of lubricating oil should be prevented. It is press-fitted into and fixed.
July 3, 1985 Published by the Japan Society of Mechanical Engineers "Handbook of Mechanical Engineering B1 Machine Element Design Tribology" Page 143

  For example, when lubricating oil such as oil or grease is filled in the reducer more than necessary, for example, when it is full, excessive internal pressure rise during filling, or temperature rise and expansion of the lubricating oil during reduction gear operation The accompanying increase in internal pressure occurs. If the increased internal pressure exceeds the oil seal escape pressure, an “oil seal missing” abnormality occurs. As a result, an enormous oil leak occurs, the reduction gear is poorly lubricated and the speed reducer is damaged.

  It is an object of the present invention to provide an oil seal that is less likely to cause “oil seal omission” by causing the pressure to escape to be higher than that of the prior art, and is less likely to cause oil leakage, lubrication failure, or breakage of a reduction gear. .

In the present invention, the above object is achieved by comprising a metal ring and a rubber lip that covers the metal ring, and a fitting portion that is fitted to the housing on the outer periphery of the lip that covers the outer periphery of the metal ring. In the oil seal formed and prevented from flowing out of the lubricating oil in the equipment, this is achieved by an oil seal characterized in that the inner diameter portion on the tip side of the metal ring can be press-fitted.
In particular, the housing is rotatably supported by a shaft member via a bearing, and a mounting portion for a lip on the outer periphery of the metal ring is formed in the housing, and a recess connected to the mounting portion for the lip is formed in the housing. It is preferable that the inner diameter portion on the tip side of the metal ring is press-fitted into the concave portion. In this case, the concave portion may be formed between the housing and the outer ring of the bearing attached to the housing, or the fitting portion of the lip and the inner diameter portion on the tip side of the metal ring may be press-fitted. It may be a concave portion. Further, a rubber seal lip portion of the oil seal may be in contact with the shaft member, or may be in contact with an inner ring of the bearing attached to the shaft member.

  According to the present invention, the oil seal exit pressure can be significantly increased as compared with the prior art. As a result, “oil seal omission” from a rotating device such as a speed reducer is unlikely to occur, oil leakage from the device is unlikely to occur, lubrication failure is unlikely to occur, and damage to the device is difficult to occur over a long period of time.

  Hereinafter, the present invention will be described in detail with reference to an embodiment in which the present invention is applied to a reduction gear for driving an arm of an industrial robot.

[Example 1]
FIG. 1 is a cross-sectional view of a speed reducer according to the present invention applied to an arm drive speed reducer for an industrial robot. In FIG. 1, the speed reducer 1 is attached to a first arm 4 of an industrial robot, and is driven by a drive motor 3 to operate a second arm 5. The speed reducer 1 is an eccentric oscillating speed reducer including a cam shaft 11, two external gear members 12, an internal gear member 13, and a support member 14.

  The support member 14 is located at both axial ends of the external gear member 12 and rotatably supports both ends of the cam shaft 11 via roller bearings. A support member 14 is located inside the internal gear member 13, and the support member 14 is loosely fitted in a through hole formed between the holes for the cam shaft 11 of the external gear member 12, and A pair of discs 18 and 19 are provided at both ends of the column portion 17, and both ends of the cam shaft 11 are rotatably supported. The column portion 17 and the pair of disks 18 and 19 are integrally connected by a connecting bolt.

  A plurality of camshafts 11 (three in this embodiment) are equally arranged on the outer peripheral portion of the input gear 16, and each camshaft 11 has crank portions lla and 11b. The crank portions 11a and 11b are formed integrally with the camshaft 11, and each has an eccentric phase of 180 degrees. Needle bearings are attached to the crank portions 11a and 11b and inserted into the holes of the external gear member 12.

  Each external gear member 12 includes a hole for accommodating the crank portions 11a and 11b of the cam shaft 11 and eccentrically moves by rotation of the cam shaft 11. A peritrochoidal tooth profile is formed on the outer periphery of the external gear member 12, and pins (internal teeth) held in a plurality of semicircular grooves formed equally on the inner periphery of the internal gear member 13 Engage with.

  The internal gear member 13 is formed on the inner peripheral surface with internal teeth having slightly more teeth than the external teeth formed on the outer peripheral surface of the external gear member 12, and meshes with the external teeth of the external gear member 12. .

  A pair of main bearings 21 are provided on the outer periphery of the pair of discs 18 and 19 so as to rotatably support the support member 14 with respect to the internal gear member 13. The main bearing 21 is an angular ball bearing, and the rigidity is increased by applying a preload at the time of mounting.

  In the speed reducer 1 having the above configuration, the output rotation of the drive motor 3 is transmitted to the transmission gear 22 having a larger number of teeth than the input gear 16 through the input gear 16 attached to the output rotation shaft of the drive motor 3 and transmitted. The camshaft 11 attached to the gear 22 is rotated at a reduced speed, and further decelerated by the camshaft 11, the external gear member 12, the internal gear member 13, and the support member 14. The reduced rotation of the support member 14 is transmitted to the second arm 5 integrally connected to the support member 14 by the bolt 20 to cause the second arm 5 to perform a desired movement. The camshaft 11 can be rotated at an increased speed or at a constant speed by appropriately selecting the gear ratio between the input gear 16 and the transmission gear 22.

  In FIG. 1, an oil seal 30 according to the present invention is attached to the outside of a main bearing 21 located on the left side. Note that the oil seal 30 of the present invention is made of a metal ring and a rubber lip that covers the metal ring in the same manner as a normal oil seal well known from Non-Patent Document 1 described above. A fitting portion 30a fitted to the housing is formed on the outer periphery of the lip that covers the outer peripheral portion of the metal ring of the oil seal 30, and this fitting portion is a device that should prevent leakage of lubricating oil (this embodiment) In the example, the inner gear member 13) is press-fitted and fixed.

  That is, a fitting recess (mounting portion) 13 a that fits into the fitting portion 30 a of the oil seal 30 is formed from the left end surface of the internal gear member 13 toward the outside of the outer ring 21 a of the main bearing 21. The fitting recess (mounting portion) 13 a is continuous with a recess formed between the internal gear member 13 and the outer side of the outer ring 21 a of the main bearing 21. An oil seal 30 is attached to the fitting recess (mounting portion) 13a so that the fitting portion 30a of the oil seal 30 is press-fitted into the entrance side of the fitting recess 13a and the tip of the oil seal 30 on the internal gear member 13 side ( The inner diameter portion 30 b at the right end) is press-fitted into the outer side of the outer ring 21 a of the main bearing 21. The lip portion 30 c of the oil seal 30 is in contact with the support member 14.

  The conventional oil seal press-fits only the fitting recess 13a, but according to the present invention, the inner diameter portion 30b at the tip of the oil seal 30 is press-fitted together with the fitting recess 13a of the oil seal. As a result, the pressure of the oil seal 30 can be significantly increased compared to the conventional case, and “oil seal loss” from the rotating equipment such as the speed reducer 1 is less likely to occur. Defects are unlikely to occur, and damage to the device is difficult to occur over a long period.

[Example 2]
Another embodiment of the present invention will be described with reference to FIG. In the embodiment shown in FIG. 2, the structure of the speed reducer 1 is the same as that of the embodiment described with reference to FIG.

  In the embodiment of FIG. 1, an oil seal 30 is mounted between the outer periphery of the outer ring 21 a of the main bearing 21 and the inner periphery of the internal gear member 13. On the other hand, in FIG. 2, the internal gear member 13 is formed with an annular groove-shaped narrow recess 13d, and the annular groove-shaped recess 13d has a lip mounting portion and a tip inner diameter portion. 30b is press-fitted. Note that the lip portion 30 c of the oil seal 30 is in contact with the support member 14.

  That is, as in FIG. 1, the inner diameter portion 30b at the tip of the oil seal 30 is press-fitted together with the fitting recess 13a of the oil seal. As a result, the pressure of the oil seal 30 can be significantly increased compared to the conventional case, and “oil seal loss” from the rotating equipment such as the speed reducer 1 is less likely to occur. Defects are unlikely to occur, and damage to the device is difficult to occur over a long period.

[Example 3]
A further embodiment of the present invention will be described with reference to FIG. In the embodiment shown in FIG. 3, the structure of the speed reducer 1 is the same as that of the embodiment described with reference to FIG. 1 or FIG.

  In the embodiment shown in FIG. 3, an oil seal 30 is mounted between the outer periphery of the outer ring 21a of the main bearing 21 and the inner periphery of the internal gear member 13 as in the embodiment of FIG. The inner diameter portion 30 b at the tip is press-fitted outside the outer ring 21 a of the main bearing 21. The lip 30c of the oil seal 30 is in contact with the outer peripheral surface of the inner ring 21b of the main bearing 21.

  As a result, the pressure of the oil seal 30 can be significantly increased compared to the conventional case, and “oil seal loss” from the rotating equipment such as the speed reducer 1 is less likely to occur. Defects are unlikely to occur, and damage to the device is difficult to occur over a long period.

It is sectional drawing of one Example of the reduction gear based on this invention applied to the reduction gear for arm drive of an industrial robot. It is sectional drawing of another Example of the reduction gear based on this invention applied to the reduction gear for arm drive of an industrial robot. It is sectional drawing of another Example of the reduction gear based on this invention applied to the reduction gear for arm drive of an industrial robot.

Explanation of symbols

30 Oil seal 30a Fitting part 30b Inner diameter part 30c Lip part

Claims (5)

  It comprises a metal ring and a rubber lip that covers the metal ring, and a fitting portion that is fitted to the housing is formed on the outer periphery of the lip that covers the outer periphery of the metal ring. An oil seal configured to prevent outflow, wherein an inner diameter portion of the metal ring on the tip side on the device side can be press-fitted.   The housing is rotatably supported by a shaft member via a bearing, and a mounting portion for a lip on the outer periphery of the metal ring is formed in the housing, and a concave portion connected to the mounting portion for the lip is formed in the housing. The oil seal according to claim 1, wherein the inner diameter portion on the tip side of the metal ring is press-fitted into the concave portion.   The oil seal according to claim 2, wherein the recess is formed between the housing and an outer ring of the bearing attached to the housing.   The oil seal according to claim 2, wherein the recess formed in the housing is a recess into which the mounting portion of the lip and the inner diameter portion on the tip side of the metal ring are press-fitted.   The oil seal according to any one of claims 2 to 4, wherein a rubber seal lip portion of the oil seal is in contact with an inner ring of the bearing mounted on the shaft member.

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