JPH0446142Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a seal structure that seals between two members that fit and rotate relative to each other.

[Prior Art] As a conventional seal structure of this type, there is one described in, for example, Japanese Utility Model Application Publication No. 60-99333. This seals the working chamber of a so-called viscous coupling spring that transmits torque by utilizing the viscous resistance of fluid. A general oil seal is used in this seal structure.

By the way, in a device such as a viscous coupling spring, internal pressure increases during differential rotation, and this pressure increase becomes large. For this reason, in the case of general oil seals having low pressure resistance, a plurality of oil seals are provided at one location, and the direction in which they are installed must be changed.

On the other hand, a pressure-resistant seal as described in Japanese Utility Model Application Publication No. 57-179649 may be used. However, in this case, when the pressure inside the coupling becomes abnormal, a part of the sealing member gets stuck between the relatively rotating members and is cut off, which causes the sealing member to become stuck between the two members and cause an abnormality. It will not come off even under pressure. However, for this reason, unless the wall thickness of the coupling body is made considerably thick, there is a risk that the body itself will be destroyed.

[Problems to be solved by the invention] As described above, when a general sealing member is used, it is difficult to make the device compact and the assembly is complicated. Furthermore, when a pressure-resistant sealing member is used, a portion of the sealing member becomes jammed between the two members due to abnormal pressure, and the device itself is destroyed, or in order to avoid this, it is necessary to increase the size and weight.

Therefore, the object of this invention is to provide a seal structure that can smoothly release abnormal internal pressure while using a pressure-resistant seal member.

[Means for Solving the Problems] In order to achieve the above object, this invention has a structure in which a recess is provided between the two members on the sealed outer side of the receiving surface.

[Function] Even if a part of the sealing member gets into the space between the two members due to abnormal pressure or the like and is cut, the small piece escapes into the recess and does not get stuck between the two members.

[Example] An example of this invention will be described below with reference to Figures 1 and 2.
The diagram will be explained.

FIG. 1 shows a cross-sectional view of a sealing structure, for example used in the so-called viscous coupling spring of FIG. The annular seal member 1 is made of a rubber-like elastic material and has a substantially X-shaped cross section, and has a pressure receiving groove 3 on the side surface on the pressure receiving side in the axial direction, and a deformation groove on the side surface axially opposite to the pressure receiving groove 3. 5 is provided. A pressure seal portion 7 is provided on the inner peripheral surface on the pressure receiving side, and a fluid seal portion 9 is provided on the opposite side of the pressure seal portion 7 in the axial direction. Further, fixed seal portions 11 and 13 are provided on the outer circumferential surface at both ends in the axial direction, respectively. Furthermore, an annular groove 1 is provided on the inner and outer peripheral surfaces.
5 and 17 are provided.

The back-up spring 19 receives the side surface of the annular seal member 1 having the deformed groove 5, and is made of resin, soft metal, or the like. The seal member 1 and the back-up spring 19 are supported within an annular groove 23 formed along the fitting peripheral surface of the first rotating body 21, which constitutes one of the two relatively rotatable members. The back-up spring 19 is received by a receiving surface 24 on one axial side within the annular groove 23. When the back-up spring 19 receives pressure on its side surface, it extends in the radial direction and comes into close contact with the circumferential surface of the second rotary body 25 constituting the other of the two members.

On the other hand, a circumferential escape groove 27 as a recess is provided on the inner surface of the first rotary body 21 at a position on the sealed outer side of the receiving surface 24 of the first rotary body 21 .

In addition, 29 in FIG. 2 is a sealed chamber formed between both the rotating bodies 21 and 25, and a viscous fluid is sealed inside. 31 is a first resistance plate that engages with the first rotating body 21 side, 33 is a second resistance plate that engages with the second rotating body 25 side, and 35 is a spacer ring.

Next, the operation of the above embodiment will be described.

First, when differential rotation occurs between the first rotating body 21 and the second rotating body 25, the first and second resistance plates 31,
33 rotates relative to each other, and the viscous resistance of the viscous fluid inside acts. Therefore, the differential motion between the two rotating bodies 21, 25 is limited, and torque transmission between the two rotating bodies 21, 25 is performed.

When the temperature of the internal viscous fluid rises due to the differential rotation and the internal pressure of the sealed chamber 29 rises,
The pressure receiving groove 3 side of the seal member 1 receives internal pressure.
Then, the pressure seal portion 7 and the fixed seal portion 11 are expanded in the radial direction and are brought into close contact with the outer circumferential surface of the second rotating body 25 and the inner circumferential surface of the annular groove 23 of the outer first rotating body 21 to seal the internal pressure. do. At the same time, the seal member 1 is deformed so as to be compressed in the axial direction, and the surface forming the deformation groove 5 is in contact with the side surface of the back-up spring 19, and the fluid seal part 9 and the fixed seal part 13 are deformed in opposite radial directions. The fluid seal portion 9 is extended to the contact surface between the back-up spring 19 and the second rotating body 25. Furthermore, since the pack-up spring 19 is received by the receiving surface 24, it is stretched in the radial direction and comes into close contact with the second rotating body 25.

In this way, the first rotating body 21 and the second rotating body 2
This seals the space between the sliding part between the seal member 1 and the seal member 5 while having a pressure-resistant function, but when the internal pressure becomes abnormally high, a part of the seal member 1 (fluid seal part 9) is pushed by the pressure and backs up. Ring 9 and second rotating body 25
It enters between both the rotating bodies 21 and 25 from between the two rotating bodies 21 and 25, and is cut by the relative rotation of both the rotating bodies 21 and 25. The small pieces of the seal member 1 cut in this way are removed from the relief groove 2.
Sent into 7. Therefore, a small piece of the sealing member 1 does not get stuck in the small gap between the first rotating body 21 and the second rotating body 25, and when the sealing member 1 receives an abnormal pressure higher than the set pressure, the pressure sealing part 7
Since the viscous fluid leaks from the lubricating seal portion 9 to the minute gap, it is possible to prevent the sealed chamber from being destroyed due to an increase in internal pressure.

Note that this invention is not limited to the above embodiment. For example, the recess can be an axial spiral groove. It is also possible to make the recess a long groove in the axial direction, and to open the end thereof to the outside.

[Effects of the invention] As is clear from the above explanation, according to the structure of this invention, it is possible to prevent clogging of the minute space between two members due to small fragments generated from the sealing member while using a pressure-resistant sealing member. be able to. Therefore, when a pressure equal to or higher than the set pressure is applied to the pressure receiving side of the seal member, internal pressure can leak from the seal portion, thereby making it possible to prevent damage caused by increased pressure within the device.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a seal structure according to an embodiment of this invention, and FIG. 2 is a sectional view of a viscous cut spring. Explanation of symbols representing main parts of the drawings: 1...Sealing member, 21...First rotation (body (member), 24...
...Receiving surface, 25... Second rotating body (member), 27...
...Escape groove (recess).

Claims (1)

[Scope of utility model registration request] a pressure-resistant seal member that seals two relatively rotatable members; an annular groove that holds the seal member;
A receiving surface provided on the sealed outside of the annular groove to receive the sealing member by contacting the sealing member, and a recess formed between the two members on the sealed outside of the receiving surface. Seal structure.