JPH0792152B2 - Sealing device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a sealing device, and more particularly to a sealing device for sealing a fluid pressure of a hydraulic power steering device (hereinafter referred to as “power steering”) mainly for an automobile. Regarding

(Prior Art) Conventionally, for a seal of a rod portion of a power steering, a metal ring having a substantially L-shaped cross section for reinforcement and a sealing material having a lip portion are entirely adhered, and a garter is attached to the seal lip portion. An oil seal type sealing device that used a combination of springs was used.

In recent years, in order to improve its operability, the set value of the fluid pressure of the power steering is increased to improve the pressure resistance characteristic of the lip seal portion. A pressure resistant seal device is used that combines a backup ring with a square or triangular cross section.

FIG. 3 is a one-sided cross-sectional view of a conventional oil seal type pressure-resistant sealing device, in which the sealing device 10 is composed of a metal ring 12 having a substantially L-shaped cross section and a seal body 14 made of an elastic material. It The seal body 14 includes a seal lip portion 16,
It is composed of a valley portion 18 and a bottom portion 20. The metal ring 12 and the seal body 14 are inevitably joined over the entire surface by an adhesive to ensure the rigidity of the seal body 14. A backup ring 30 is installed opposite to the radial portion 24 of the metal ring 12 via the bottom portion 20 of the seal body 14.

(Problems to be Solved by the Invention) In the pressure-resistant seal device of such a type, the deformation of the rubber material at the bottom part or the bottom part of the valley part of the seal body, which is transmitted from the lip seal part due to fluid pressure, is This is suppressed by increasing the rigidity of the fixed metal ring for reinforcement and the seal body by bonding them over the entire surface. However, according to the experience of the present inventor, stress is concentrated on the bottom portion or the lower portion of the valley of the seal body due to repeated increase and decrease of the fluid pressure during use, causing fatigue fracture due to repeated pressure, and this portion The seal body sometimes ruptured between the valley bottoms. Referring to FIG. 3, a through crack occurs from the valley portion 18 to the bottom portion 20.

Thus, in the conventional case, the metal ring 12 and the seal body 14 are
And were bonded over the entire surface with an adhesive. This is intended to reinforce the seal body 14 with the metal ring 12 and secure its rigidity. Certainly such a structure is preferred for reinforcement of the seal body 14. Conventionally, this type of sealing device is good because the sealing surface is mainly applied to a rotating surface that makes a rotary motion. However, in recent years, this has been applied to reciprocating shafts, and working fluid pressure has been increased,
In such a case, as described above, the portion in contact with the central portion (corner portion) of the L-shaped metal ring 12 and the valley portion 18 are
There is a risk of fatigue failure below.

An object of the present invention is to improve the drawbacks of such an oil-sealing type pressure-resistant sealing device, and to provide a sealing device having improved pressure resistance, durability, and reliability, particularly a sealing device for automobile power steering. Is.

(Means for Solving the Problems) In order to achieve such an object, the present inventor has conducted various studies and has found that a seal main body having a lip seal portion made of synthetic rubber or the like and a substantially L-shaped or substantially U-shaped seal body. With a metal ring having a V-shaped cross section so as to be in an unbonded state only at the bottom of the seal body, in other words, preferably, only the region from the high pressure side end surface of the seal body to the substantially valley bottom part In the configuration, the metal ring and the seal body are configured to adhere to each other,
The present invention has been completed based on the knowledge that the above-described object of the present invention can be achieved when the seal main body made of an elastic body is configured to be elastically deformable at the waist and bottom of the seal main body.

Since the metal ring is originally provided for reinforcement,
As a matter of course, it has been considered that the entire surface of the seal body must be integrally joined to ensure rigidity. However, according to the knowledge of the present inventor, when pressure resistance is required as described above, unexpectedly, rather flexibility is required, and it is sufficient if the seal body is retained as a metal ring. I found out that Further, they have also found that in order to secure the rigidity of the seal body in order to further increase the pressure resistance, it is necessary to provide a backup ring rather than strengthening the joint with the metal ring.

Therefore, the gist of the present invention is to provide a seal main body made of an elastic body having a seal lip portion, a valley portion, and a bottom portion that come into contact with the seal surface, and to reinforce the seal main body. A sealing device composed of an assembled metal ring having a substantially L-shaped cross section, wherein the metal ring has a first portion extending in a direction substantially perpendicular to the axial direction and a second portion extending in the axial direction. Part of the contact surface area between the first portion and the seal body, and in the contact surface area between the second portion and the seal body, at least from the high pressure side end surface of the seal body. The sealing device is characterized in that it is configured in such a manner that regions up to a position substantially corresponding to a valley bottom are joined together.

According to another feature of the present invention, the pressure resistance is further improved by providing a backup ring between the bottom of the seal body and the metal ring in a state not joined to the bottom of the seal body.

The metal ring for reinforcement can be installed by pressing the metal ring into the seal housing.In any case, the twist of the seal lip due to pressure or friction is limited, and the seal lip is always kept normal. Any material having a function of contacting the sealing surface can be used. In other words, the joining of the metal ring and the seal body with the adhesive may be limited to the extent necessary and sufficient to exert such a function.

The backup ring may have a flat washer-shaped or an angle-shaped cross section, and both may be conventional ones.

As described above, in the sealing device according to the present invention, between the annular seal body and the metal ring, which has been conventionally entirely bonded, at least a part thereof is left unbonded, so that one type of play is provided. Therefore, even if the high pressure is repeated, the deformation of the seal lip portion due to the pressure is distributed to the entire seal body instead of being concentrated on a part of the seal body unlike the conventional pressure-resistant seal device. Therefore, fatigue failure does not occur.

Further, according to the present invention, by further incorporating a backup ring having various cross-sectional shapes between the bottom of the seal body and the metal ring, the seal body can be further reinforced, and a relatively small square or triangular shape in the related art can be achieved. When the cross-section has a flat washer shape or an angle shape as compared with the cross-section backup ring, the functions of these backup rings are significantly enhanced, and the pressure resistance and durability of the sealing device can be significantly improved.

Therefore, according to the present invention, the entire surface of the seal body should not be joined and at least a part of the seal body should not be joined. When the metal ring has an L-shaped cross section composed of the axial direction portion and the radial direction portion, the gist of the present invention is that the metal ring and the seal lip portion extending in the axial direction of the sealing surface. A seal device comprising a seal body joined to the metal ring, wherein at least a part of the contact surface region is joined from the high pressure side end in the axial direction part of the metal ring. It is a sealing device characterized by the above.

That is, in other words, at least the radial portion of the metal ring is configured so as not to be joined to the seal body.

Such a joining region is from the high pressure side end to a position preferably corresponding to the bottom of the seal body. This is because at least the abutting region is joined to perform a reinforcing function. The remaining non-bonding region constitutes a kind of play for the deformation of the seal lip portion as described above, and the range of the non-bonding region is appropriately determined depending on the required deformation amount. However, if the area is too large, the reinforcing effect will be insufficient, so the range is appropriately limited.

In the case of the contact surface between the metal ring and the seal body, normally, after applying the adhesive to the metal ring in advance, the appropriate elastic material described below is cast around it and integrally molded. To do. In this case, if an area corresponding to the contact surface where bonding is not desired is cast without applying an adhesive, the area becomes a non-adhesive area.

At the time of molding, put a metal ring and a separately molded backup ring in a mold and then mold by molding an elastic body, or mold the metal ring ring, backup ring and elastic body at the same time in the mold By doing so, the surface of the seal main body which is in contact with the backup ring is not adhered, and the sealing device in which the backup ring is incorporated can be obtained.

The backup ring can be selected from tetrafluoroethylene resin (Teflon-trade name, etc.) or various thermoplastic elastomers, thermoplastic synthetic resins, thermosetting synthetic resins, soft metals, etc., depending on the usage conditions. Can be used in combination with multiple backups selected from these materials.

The lip seal part is mainly made of oil resistant synthetic rubber,
It is selected from various rubbers, thermoplastic elastomers, soft synthetic resins, etc. suitable for the fluid used.

A garter spring or the like may be incorporated in the lip seal portion on the surface opposite to the movement surface of the seal lip portion to enhance the contact force of the seal lip portion with respect to the seal surface and enhance the sealing performance.

(Operation) Here, the present invention will be described more specifically with reference to the accompanying drawings. The same members are designated by the same reference numerals.

FIG. 1 is a one-sided sectional view of a sealing device according to the present invention. In the drawing, the sealing device 10 comprises a metal ring 12 having a substantially L-shaped cross section and a sealing body 14 made of an elastic material. The seal body 14 includes a seal lip portion 16, a valley portion 18, and a bottom portion.
Composed of 20. Reference numeral 22 indicates an annular spring such as a garter spring. This is a conventional seal lip 16
Is pressed against a seal surface or a shaft surface (not shown). In the illustrated example, the metal ring 12 is composed of an axial portion 23, which is a second portion extending along the axial direction, and a radial portion 24, which is a first portion extending substantially at right angles to the axial direction. In the present invention, the joining region with the seal body 14 is provided at least for the length from the high pressure side end portion 25 of the axial portion 23 to the position corresponding to the valley bottom portion of the seal body. The rest are non-bonded areas. The back surface of the axial portion 23 is in a state of being entirely bonded.

According to the present invention, the contact surface region between the radial portion 24 of the metal ring 12 and the seal body 14 is in an unbonded state, but in the axial portion 23, at least one from the high pressure side end portion 25 thereof. The area of the part, preferably the area of the abutment surface to the bottom of the valley 18, is fitted using an adhesive. As a result, the shearing force applied to the seal main body 14 during the reciprocating movement of the seal surface is dissipated by the friction between the metal ring 12 and the seal main body 14 in that region, so that the deterioration of the material of the seal main body, the shearing, etc. Will not occur and will be usable for a long time.

In the figure, it is not always necessary to provide an elastic body portion on the back surface of the axial direction portion 23, but when attached to a housing (not shown), it is said that fluid leakage between the housing and the outer peripheral surface of the metal ring is prevented. From the point of view, it is preferable to bond the entire back surface.

FIG. 2 is a one-sided cross-sectional view showing an example in which a bappup ring 30 is provided between the metal ring 12 and the seal body 14.

When the backup ring 30 is provided as in the illustrated example, the backup ring 30 and the seal body 14 are not joined to each other over the entire surface. There is no joining between the backup ring 30 and the metal ring 12.

By providing such a backup ring, not only is the reduction in strength and rigidity caused by providing the non-bonding region between the seal body 14 and the metal ring 12 compensated,
Prevents damage to the seal body even with large eccentricity of the shaft,
The sealing property can be maintained.

Further, by inserting the metal ring and the backup ring into the mold and integrally molding with the seal body, a seal device in which the bottom surface of the seal body is a non-bonding region can be obtained regardless of the state of the adhesive of the metal ring. . Further, by such a molding method, since the annular recess for fitting the backup ring is eliminated, the mold structure is simplified, the molding is facilitated, and the dimensional accuracy of the sealing device is improved. Seen.

Here, the effects of the sealing device according to the present invention are summarized and shown in comparison with the conventional example.

(Effects of the Invention) With the above-described configuration, according to the present invention,
Even when used under high pressure such as in power steering, the bottom of the lip main body, which is provided with the lip seal part that is most strongly affected by the fluid pressure, can be elastically deformed freely, and the lip seal part Since the lower back is protected, it is possible to provide a durable and reliable sealing device that is free from damage and leakage.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of one side of a sealing device according to the present invention; FIG. 2 is a sectional view of one side of the sealing device according to another embodiment of the present invention; and FIG. It is a one-sided sectional view of a conventional oil seal type pressure-resistant seal device. 10: Sealing device, 12: Metal ring 14: Seal body, 16: Seal lip part 18: Valley part, 20: Bottom part

Claims (4)

[Claims] 1. A seal body made of an elastic body having a seal lip portion, a valley portion, and a bottom portion that come into contact with a sealing surface,
A seal device for reinforcing the seal body, comprising a metal ring having a substantially L-shaped cross section incorporated in the seal body, the metal ring extending in a direction substantially perpendicular to the axial direction. A first portion and a second portion extending along the axial direction, and in a state where the contact surface region between the first portion and the seal body is not joined, and the second portion and the seal body are in contact with each other. A sealing device, characterized in that, among the surface regions, at least a region from a high-pressure side end face of the seal body to a position substantially corresponding to a valley bottom is joined. 2. A seal main body made of an elastic body having a seal lip portion, a valley portion, and a bottom portion that come into contact with the seal surface,
A seal device for reinforcing the seal body, comprising a metal ring having a substantially L-shaped cross section incorporated in the seal body, the metal ring extending in a direction substantially perpendicular to the axial direction. A first portion and a second portion extending along the axial direction, and in a state where the contact surface region between the first portion and the seal body is not joined, and the second portion and the seal body are in contact with each other. Of the surface regions, at least the regions from the high-pressure side end face of the seal body to a position substantially corresponding to the valley bottom are joined together, and between the bottom of the seal body and the metal ring of the seal body. A sealing device, characterized in that a backup ring is provided in a state where it is not joined to the bottom portion. 3. The sealing device according to claim 2, wherein the backup ring has a flat washer-shaped or angle-shaped cross section. 4. The metal ring and the backup ring are put in a mold at the same time to cast an elastic body, or the metal ring, the backup ring and the elastic body are put in a mold at the same time and molded. The sealing device according to claim 2 or 3.