JP2010230104A - Come-off preventive structure of sealing member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the come-off preventive structure of a sealing member of a reduction gear capable of preventing the come-off of the sealing member by using a simple method without requiring the processing of the sealing member. <P>SOLUTION: A housing 62 of the reduction gear has a groove 14. An elastic adhesive 12 is applied to an inner peripheral part of the groove 14. Since an outer peripheral part of an oil seal 10 in the groove 14 is released from pressure when the oil seal 10 is pressed therein, it is expanded by an elastic restoring force to be in contact with the elastic adhesive 12 in the groove 14. Thereby the oil seal 10 is fixed at the groove 14 to strengthen the fixation of the oil seal 10 with the housing 62. Since the processing of the oil seal 10 is not required and a commercially-available silicone-based liquid gasket is used as the elastic adhesive 12, the come-off of the sealing member is prevented by using the simple method which is reduced in man-hours and cost. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a retaining structure for a sealing member that is press-fitted and fixed to a housing or a seal supporter of a reduction gear.

In a gear type reduction gear, a certain amount of lubricating oil is enclosed in a gear box in order to prevent gear wear and reduce cooling by reducing friction. Therefore, it is required that the lubricating oil does not leak to the outside.
Generally, an oil seal is used as a member for preventing leakage of lubricating oil in a rotating part such as an input / output shaft. The oil seal is fixed to the speed reducer housing and the rotating part of the gear box. Further, a seal cap is used at a place other than the rotating part to prevent leakage of lubricating oil to the outside of the speed reducer.

However, due to the following reasons 1 to 3, an oil seal or a seal cap (hereinafter abbreviated as “sealing member”) in which rubber is provided on the outer periphery of the metal ring for preventing leakage of lubricating oil from the housing or the seal supporter. There was a problem that it was missing.
1. With the heat generated by the rotation of the gear and the stirring of the lubricating oil, the outer peripheral portion of the sealing member is softened by the heat.
2. The sealing member mounting portion of the housing or the seal supporter expands and the size increases.
3. The softened sealing member loses tension with the housing and the inner periphery of the seal supporter when the pressure inside the speed reducer increases.

  Therefore, there is an oil seal retaining structure shown in Patent Documents 1 to 4 as a prior art.

Japanese Utility Model Publication No. 6-73383 Japanese Utility Model Publication No. 62-45468 JP-A-8-193661 JP 2003-214359 A

The idea of Patent Document 1 is that the oil seal is pulled out by engaging the deformed portion bulged on the outer peripheral surface of the oil seal with the fixed groove recessed in the inner peripheral surface of the shaft insertion hole of the crankcase. It is preventing.
The inventions and inventions of Patent Documents 2 to 4 disclose an oil seal retaining structure in which an annular protrusion formed on an outer peripheral surface of an oil seal is engaged with a groove provided in a housing.

However, the idea of Patent Document 1 is merely that a sealing elastic material is bulged in the fixing groove of the crankcase, and heat generation and internal pressure increase caused by damage to the sealing material and gear meshing that occur when the oil seal is press-fitted. It is not clear whether or not the oil seal can be prevented from coming off when this occurs. Further, the bulging deformed portion engaged with the fixing groove of the crankcase is a convex saddle curved surface formed on the outer surface of the oil seal, and thus special processing is required.
Furthermore, the inventions and inventions of Patent Documents 2 to 4 require that an annular protrusion be formed on the outer peripheral surface of the oil seal, respectively, so that the member that reinforces the oil seal corresponds to the locking groove formed in the housing. There is a problem that it takes a lot of cost and man-hours to realize the oil seal prevention, such as having to be bent.

  Since a large number of oil seals and seal caps are used in one speed reducer, it is desirable that a structure for preventing the oil seals and seal caps to be realized by a method that does not require cost and processing time.

Therefore, as a method for preventing the oil seal and the seal cap from coming off without changing the shape of the oil seal and the seal cap, a method of fixing and holding the fitting portion of the reducer housing by press-fitting to provide a tightening allowance. There is. In this method, an adhesive may be applied to the outer periphery of the sealing member to prevent the sealing member from being scratched during press-fitting and to increase the fixing holding force. Since the use of an agent is not recommended, the sealing member must be prevented from coming off without applying an adhesive.
Further, in this method, in order to enhance the retaining effect, the roughness is given to the fitting portion of the housing of the speed reducer. However, when the housing is made of a light alloy such as aluminum or titanium, it is soft. There was a problem that man-hours were required to produce roughness.

  An object of the present invention is to provide a sealing member retaining structure that solves the above-described problems of the prior art.

The present invention is a reducer in which lubricating oil is enclosed in a housing and a sealing member is press-fitted into the housing or the seal supporter.
A groove is formed in the circumferential direction of the inner peripheral portion of the housing or the seal supporter, and an elastic adhesive is applied to the groove,
A portion corresponding to the groove of the sealing member is released from the pressure due to the press-fitting and is bonded to the elastic adhesive to solve the above problem.
In addition, as described in claim 2, the cross-sectional shape of the groove may be a quadrangle, a right triangle, an isosceles triangle, or a semicircle according to the application.
Further, as described in claim 3, the groove is not limited to a continuous one in the circumferential direction, and may be intermittent.
Furthermore, as in claim 4, a plurality of the grooves may be formed at intervals in the axial direction.

According to the present invention, by providing a groove in the speed reducer housing or seal supporter, the press-fitted sealing member swells in the groove due to the rubber elastic restoring force of the outer peripheral portion, and the elastic adhesive applied to this groove The agent is prevented from coming off by adhering to the sealing member. Here, "elastic adhesive" is an adhesive that forms a rubber-like elastic body that cures at room temperature. Cold resistance, heat resistance, water resistance, weather resistance, electrical insulation, oil resistance, vibration resistance Excellent in impact resistance. In addition, since the elastic adhesive is rich in fluidity, it can be easily filled into a small gap, and functions effectively as a sealing material for the joint surface particularly at high temperatures.
Therefore, the application of the elastic adhesive to the groove has the following three effects.
1. It is possible to prevent the sealing member from being damaged due to contact with the edge portion of the groove when the sealing member is press-fitted.
2. The fixing and holding force of the sealing member can be improved by the adhesiveness of the elastic adhesive.
3. Since the elastic adhesive is cured into a rubber-like elastic body when exposed to air, it has a performance as a sealing material and can enhance the effect of preventing lubricant leakage.

  Furthermore, the cross-sectional shape in the axial direction of the groove is usually a rectangular shape that can be easily processed, but may be an isosceles triangle, a right triangle, or a semicircle if necessary. Although isosceles triangles, right triangles, and semicircles are difficult to machine, they have the advantage that they are more effective in preventing scratches and preventing slipping when pressed. Moreover, since processing is unnecessary for the sealing member itself, a commercially available product can be used, and the cost and man-hours can be reduced. For example, a commercially available silicone liquid gasket may be used as the elastic adhesive.

(A), (b) is a longitudinal cross-sectional view before and after press-fitting of the oil seal of the speed reducer in which the oil seal is disposed on the rotation shaft of the speed reducer provided with a groove in the housing. (A), (b) is a longitudinal cross-sectional view before and after press-fitting of the seal cap of the speed reducer in which the seal cap is disposed in the speed reducer provided with a groove in the seal supporter.

Embodiments of the present invention will be described below with reference to the accompanying drawings 1 and 2.
FIG. 1A is a longitudinal sectional view of the speed reducer before the oil seal is provided on the rotation shaft of the speed reducer provided with a groove in the housing, and FIG. 1B is a speed reduction provided with a groove in the housing. FIG. 2A is a longitudinal cross-sectional view of the speed reducer before the seal cap is disposed on the speed reducer provided with a groove in the seal supporter. FIG. 2B is a longitudinal sectional view of the speed reducer after the seal cap is disposed on the speed reducer provided with a groove in the seal supporter.
In FIGS. 1A and 2A, the sizes of the oil seal and the seal cap are exaggerated for easy understanding that the oil seal and the seal cap are “press-fitted”. Yes.

First, the sealing member retaining structure shown in FIG. 1 in which an oil seal is disposed on the rotating shaft of a reduction gear having a groove in the housing will be described.
The housing 62 is provided with a groove 14 having a depth of 0.5 mm to 0.8 mm. The elastic adhesive 12 is applied to the inner peripheral portion of the groove 14. A commercially available silicone liquid gasket is used for the elastic adhesive 12. Since the press-fit portion of the oil seal 10 has a tightening allowance of 0.3 mm to 0.5 mm, the pressure from the housing 62 is received when the oil seal 10 is press-fitted in the arrow direction shown in FIG. However, since the outer peripheral portion of the oil seal 10 in the groove 14 is released from the pressure, it swells to come into contact with the elastic adhesive 12 in the groove 14 as shown in FIG. As a result, the oil seal 10 is firmly fixed at the groove 14, and the oil seal 10 and the housing 62 are firmly fixed.
Further, since the elastic adhesive 12 has adhesiveness and is in a liquid state before being cured, the elastic adhesive 12 is evenly filled in the inner peripheral portion of the groove 14 and prevents leakage of lubricating oil from between the oil seal 12 and the groove 14. After curing, a rubber-like elastic body is formed, so that it functions as a sealing material excellent in watertightness, airtightness, adhesiveness, followability, durability, vibration resistance, impact resistance and heat resistance. Therefore, by applying the elastic adhesive 12 to the groove 14, the adhesion between the oil seal 10 and the housing 62 is strengthened due to the adhesiveness, and the effect of preventing the lubricating oil leakage can be enhanced by the role as a sealing material. .

Further, the elastic adhesive 12 is required to maintain a certain elastic force capable of preventing damage to the oil seal 10 until the oil seal 10 is press-fitted after application. By applying the elastic adhesive 12 having such properties, it is possible to prevent the oil seal 10 from being damaged due to contact with the edge portion of the groove 14 when the oil seal 10 is press-fitted. Therefore, an instantaneous adhesive or a curable adhesive cannot be used as the elastic adhesive 12.
The amount of the elastic adhesive 12 is preferably about half of the groove 14. By setting the amount of the elastic adhesive 12 to about half of the groove 14, it is possible to perform both the function of bonding the oil seal 10 and the housing 62 and the sealing function that enhances the lubricating oil leakage prevention effect.

The shape of the groove 14 may be a square that can be easily processed. However, when it is desired to prevent damage to the oil seal 10 due to the edge portion of the groove 14 with a higher probability or to further enhance the retaining effect of the oil seal 10, a right triangle, an isosceles triangle, or a semicircle may be used.
Although not shown in the drawings, the groove 14 in the inner peripheral portion of the housing is not a continuous shape along the cylindrical inner peripheral portion of the housing or the seal supporter, and may be provided intermittently. A plurality may be provided at intervals. By providing a plurality of grooves 14, the sealing member and the housing or the seal supporter are caught more easily, so that the sealing member is more difficult to come off.
As described above, the number and shape of the grooves 14 may be appropriately determined according to a desired function.

Next, FIG. 2 shows a sealing member retaining structure in which a seal cap is disposed on a reduction gear provided with a groove in the seal supporter.
As shown in FIG. 2, the present invention can be used not only at locations where oil seals are used but also where seal caps are used. Further, the groove may be provided in the seal supporter instead of the housing.
The seal cap 20 is a sealing lid for preventing leakage of lubricating oil from a hole provided for processing and preventing entry of foreign matter from the outside, such as a gear box, and is used at a place other than the rotating shaft of the speed reducer. It is done.
Since the outer periphery of the seal cap 20 is made of rubber, when it is press-fitted in the direction of the arrow shown in FIG. 2A, it receives pressure from the seal supporter 70 as in the case of press-fitting the oil seal, When it reaches, it is released from the pressure and swells in contact with the elastic adhesive 12 in the groove 14 due to the elasticity of rubber as shown in FIG. Thereby, it is fixed to the seal cap 20 and the groove 14, and the seal cap 20 can be prevented from coming off.
A commercially available silicone liquid gasket may also be used for the elastic adhesive 12 applied to the seal supporter 70. The amount of the elastic adhesive 12 applied to the groove 14 is preferably about half of the groove 14 as in the case where the oil seal is press-fitted.

Thus, since the present invention only needs to be a press-fitting type sealing member, it is possible to prevent the oil from being removed regardless of the type of the sealing member such as an oil seal or a seal cap. Further, it is only necessary to provide a groove in the housing or the seal supporter, and it is not necessary to process the sealing member, and a commercially available silicone-based liquid gasket can be used as the elastic adhesive, thereby reducing the man-hours and costs.
Further, the shape of the groove may be a right triangle, an isosceles triangle or a semicircle according to the application.
Further, a plurality of grooves may be provided intermittently along the cylindrical inner peripheral portion of the housing or the seal supporter, or may be provided at intervals in the axial direction. By providing a plurality of grooves, the sealing member and the housing or the seal supporter are caught more easily, and the sealing member is more difficult to be removed, and it is not necessary to form the groove without any gaps. In this way, it is possible to enhance prevention of the sealing member from coming off.

10 Sealing member (oil seal)
12 Elastic adhesive 14 Groove 20 Sealing member (seal cap)
62 Housing 70 Seal supporter

Claims (4)

In a reducer in which lubricating oil is enclosed in a housing and a sealing member is press-fitted into the housing or the seal supporter,
A groove is formed in the circumferential direction of the inner peripheral portion of the housing or the seal supporter, and an elastic adhesive is applied to the groove,
A portion corresponding to the groove of the sealing member is released from the pressure by the press-fitting and is bonded to the elastic adhesive.
Sealing member retaining structure.   The sealing member retaining structure according to claim 1, wherein an axial section of the groove is a quadrangle, a right triangle, an isosceles triangle, or a semicircle.   The sealing member retaining structure according to claim 1, wherein the groove is formed at two or more locations intermittently in the circumferential direction.   The sealing member retaining structure according to any one of claims 1 to 3, wherein the groove is formed at an interval of two or more locations in the axial direction.

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