JP2000046196A - Release protection device for oil seal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light and inexpensive means that offers a release protection effect of preventing the rubber seal body of an oil seal from slipping off a mounting opening. SOLUTION: A rubber seal body 5 that seals the gap between an opening 3 in a housing 2 and a rotary shaft 4 is mounted on its axially outward end face with a generally polygonal lock ring 16 so that straight sections 18 mainly engage with the seal body 5 and that arc sections 17 fit in an annular groove 21 cut in the internal surface of the opening 3. The lock ring 16 is easily mounted or demounted by elastic deformation of a pair of hooked ends 19 and 20 being pinched. Release-oriented movement of the seal body 5 out of the opening 3 applies shearing force to the lock ring 16, which however provides a secure release protection effect despite of its light weight, owing to its spring steel property.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seal device generally called an oil seal, and more particularly to a seal device in which a seal body is made of rubber and is fitted around a shaft such as a rotating shaft.
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shaft sealing device for preventing oil or other fluid such as lubricating oil from leaking from a gap around a shaft body, and to a device for preventing a seal body from coming out of the gap.

[0002]

2. Description of the Related Art For example, in a differential gear mechanism used for a vehicle such as a forklift, an oil seal used in a portion where a rotating shaft passes through an opening provided in a casing has a structure as shown in FIG.
That is, the oil seal 1 having a general structure is composed of the housing 2
In order to close a gap between the opening 3 formed in the opening 3 and the rotating shaft 4 passing through the opening 3, a seal body 5 attached to the opening 3 side is provided. The seal body 5 is formed of rubber of a material having excellent oil resistance and abrasion resistance, and has two seal lips 6 and 7 slidably contacting the surface of the rotating shaft 4.
A cylindrical portion 9 extending closely toward the interior 8 of the housing 2 in close contact with the inner surface of the opening 3 and sealing lips 6, 7 and the cylindrical portion 9 so that the overall cross-sectional shape is substantially Y-shaped. And an annular portion 10 connecting them.

[0003] The oil seal 1 is provided inside the housing 2.
Is provided in order to prevent the lubricating oil filled in from leaking from the gap between the opening 3 and the rotating shaft 4.
In order to prevent the seal body 5 from falling out of the opening 3, the outer diameter of the cylindrical portion 9 of the seal body 5 is made slightly larger than the inner diameter of the opening 3, so that the cylindrical portion 9 is
By press-fitting, the cylindrical portion 9 is pressed against the inner surface of the opening 3 by the elastic force of rubber to generate a binding force as a frictional force. However, the strength of the binding force alone does not become constant due to variations in the processing accuracy of the opening 3 or the like, and the binding force becomes weaker as the rubber deteriorates. Has an annular stopper plate 11 attached to the outer surface 13 of the housing 2 with bolts 12 or the like to prevent the seal body 5 from coming out of the opening 3.

[0004]

As described above, when the rubber constituting the seal body 5 is deteriorated and the binding force is reduced, the stopper body 11 alone can prevent the seal body 5 from coming out of the opening 3. As shown in FIG. 5, the stopper body 11 may be deformed as shown in FIG. 5 and the seal body 5 may come off. As a countermeasure, the thickness of the stopper plate 11 may be increased,
It is necessary to increase the rigidity of the stopper plate 11 by squeezing the stopper plate 11 with a press to form a fold for reinforcement in the radial direction. However, when the thickness of the stopper plate 11 is increased, the weight increases, and when the stopper plate 11 is reinforced by press molding, the strength is slightly increased but the cost is increased.

Accordingly, the present invention addresses the above-mentioned problems in the prior art and, in order to prevent the rubber seal body of the oil seal from falling out of the attached opening, the rubber of the seal body is provided. The purpose of the present invention is to provide a new retaining means that not only does not increase the weight or increase the cost, but also provides a binding force by elasticity and a greater retaining effect than when a stopper plate is used. .

[0006]

According to the present invention, there is provided a device for preventing an oil seal from coming off, which is described in each claim as means for solving the above-mentioned problems.

[0007]

According to the present invention, there is provided an oil seal having a rubber seal main body which is basically mounted on an inner surface of an opening and fitted on a shaft passing through the opening. An annular groove formed on the inner surface of the opening, and a portion engaged with the axially outer side surface of the seal body, a portion attached to the annular groove in an elastically deformed state, and a pair of end portions bent inward. And a part of the lock ring is engaged with the axially outer side surface of the seal body to prevent the seal body from coming off, and the other part is The lock ring can be easily mounted in an annular groove formed on the inner surface of the opening while the entire lock ring is elastically deformed by pinching a pair of bent ends. As a result of the seal body being supported by the annular groove of the opening via the tough lock ring, even with a small diameter lock ring, a large retaining effect is achieved, and the seal body can be reliably prevented from falling out of the opening. it can. Moreover, there is an advantage that the lock ring is lightweight and can be manufactured at low cost.

More specifically, according to the present invention, the shaft inserted into the opening is a rotary shaft, and a seal lip is formed on a rubber seal body so that the seal lip can slide on the rotary shaft. It can be implemented as a so-called lip seal device in contact. Accordingly, even when the shaft body comes into sliding contact with the seal lip, the seal body can be held inside the opening to prevent the seal body from coming off, and the shaft can be securely sealed around the rotary shaft.

The lock ring can be made of a lightweight, inexpensive, and tough spring steel wire. The lock ring includes a plurality of substantially arcuate portions as portions fitted into the annular groove of the opening, and a plurality of substantially linear portions as portions engaging the axially outer side surface of the seal body. The lock ring has a plurality of substantially linear portions having a substantially polygonal shape. Thereby, while being lighter than the conventionally used stopper plate, a tougher lock ring securely holds the seal body in the opening,
The seal body has a reliable retaining effect.

[0010]

1 to 3 show a preferred embodiment of an oil seal provided with a retaining device according to the present invention. FIG.
Also, like the conventional oil seal 1 shown in FIG. 5, the oil seal 15 according to the embodiment of the present invention also has oil resistance and abrasion resistance fitted to the rotating shaft 4 passing through the opening 3 of the housing 2. A seal body 5 made of rubber is provided, and its seal lips 6 and 7 are in sliding contact with the surface of the rotating shaft 4. The outer diameter of the cylindrical portion 9 of the seal body 5 is also preferably slightly larger than the inner diameter of the opening 3 so that a binding force acts on the inner surface of the opening 3. However, the stopper plate 11 shown in FIG. 4 and the bolt 12 for fixing the stopper plate need not be provided unless the pressure difference between the inside 8 and the outside of the housing 2 is very large.

According to the features of the present invention, the oil seal 15 of the embodiment has a lock ring 16 having a shape as shown in FIG. The lock ring 16 is formed from a spring steel wire having a diameter of, for example, 1.6 mm into a shape close to a closed curve as illustrated. The shape of the lock ring 16 is not necessarily limited to that shown in FIG. 3, but in the case shown in the figure, four long and short arc-shaped portions 17, three linear portions 18, and both ends are bent inward. It has a shape having a pair of bent ends 19 and 20. When no force acts on the lock ring 16, a slight space is formed between the bent ends 19 and 20.

An annular groove 21 is formed in the inner surface of the opening 3 of the housing 2 so as to receive the arcuate portion 17 of the lock ring 16. The diameter of the bottom surface of the annular groove 21 is the same as that of the lock ring 1 when no force is applied.
6 is smaller than the outer diameter of the arcuate portion 17. Therefore, the curved end portions 19 and 20 of the lock ring 16 are pinched with a fingertip to reduce the distance therebetween, so that the arc-shaped portion 17 is formed.
When the lock ring 16 is mounted in the annular groove 21 in a state where the outer diameter of the lock ring 16 is small, the plurality of arc-shaped portions 17 of the lock ring 16 engage with the annular groove 21 and the lock ring 16 is opened. Securely fixed inside.

Therefore, after the rubber seal body 5 fitted to the rotary shaft 4 is driven into the opening 3 in the axial direction on the rotary shaft 4, the lock ring 16 Opening the arcuate portion 17 through the opening 3 while reducing the outer diameter of the arcuate portion 17 by reducing the distance between the bent ends 19 and 20 so that the linear portions 18 come into contact with and engage with each other.
Into the annular groove 21. As a result, the stopper is securely prevented from coming off, and the seal body 5 does not come off in the axial direction.

Since the shear strength and bending strength of the spring steel wire having a diameter of 1.6 mm are greater than those of a steel plate having a thickness of 2.3 mm, the locking effect of the lock ring 16 having the shape shown in FIG. 4 and the stopper plate 11 shown in FIG. In addition, lock ring 16
Since it is a ring-shaped member made of a thin spring steel wire, it is light in weight, and can be easily attached to and detached from the annular groove 21 in a state of being pinched and contracted with a fingertip. (See FIGS. 4 and 5) are unnecessary, workability is good, and there is no variation in seal holding force between individual oil seals, so that a uniform retaining effect can be obtained, and unit cost is low and cost is low. It has advantages such as being able to reduce.

Although the shape of the lock ring 16 in the illustrated embodiment is close to a square with rounded corners, it can generally be close to a polygonal shape. The shape of the arcuate portion 17 engaged with the linear portion 18 may be a shape slightly protruding radially outward from the end of the linear portion 18 or a modified shape opposite thereto. Further, the cross-sectional shapes of the lock ring 16 and the annular groove 21 are not limited to a circle, but may be a rectangle or another shape.

[0016]

According to the present invention, the rubber seal body of the oil seal is prevented from coming out of the opening in which the oil seal is mounted, so that there is no aging and the weight and cost are increased. Without this, a reliable retaining effect of the seal body can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a preferred embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of the embodiment shown in FIG.

FIG. 3 is a front view showing a main part of the embodiment.

FIG. 4 is a longitudinal sectional view showing a conventional example.

5 is a longitudinal sectional view showing a problem of the conventional example shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Conventional oil seal 2 ... Housing 3 ... Opening 4 ... Rotating shaft 5 ... Rubber seal main body 6,7 ... Seal lip 9 ... Cylindrical part 10 ... Circular part 11 ... Stopper plate 15 ... Oil seal 16 ... Lock ring 17 ... Arc part 18 ... Linear part 19,20 ... Bend end 21 ... Circular groove

Claims (5)

[Claims] 1. An oil seal having a rubber seal body fitted to an inner surface of an opening and fitted to a shaft passing through the opening, and formed on an inner surface of the opening. A partially open portion having an annular groove, a portion engaged with the axially outer side surface of the seal body, a portion attached to the annular groove in an elastically deformed state, and a pair of inwardly bent ends; An oil seal retaining device comprising a ring-shaped lock ring. 2. The device according to claim 1, wherein the shaft is a rotating shaft, a seal lip is formed on the rubber seal body, and the seal lip slidably contacts the rotating shaft. An oil seal retaining device. 3. An oil seal retaining device according to claim 1, wherein said lock ring is made of a spring steel wire. 4. The method according to claim 1, wherein
A plurality of substantially arcuate portions as portions where the lock ring is mounted in the annular groove of the opening, and a plurality of substantially linear portions as portions engaging the axially outer side surface of the seal body. A device for retaining an oil seal, comprising: 5. The oil seal retaining device according to claim 4, wherein a plurality of substantially linear portions of the lock ring have a substantially polygonal shape.