JP2003130230A - Oil seal and its forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the transfer of defects on an outer peripheral lip by preventing defects on a metal mold when molding, and to prevent rubber spread around the periphery of an insert metal from flowing out to the outside as foreign matters. SOLUTION: This oil seal is constituted of the disc type insert metal, an inner peripheral lip formed by an upper side dust lip and a lower side dust lip fixed on the inner peripheral side of the insert metal and the outer peripheral lip fixed on the lower surface of the outer peripheral side of the insert metal. A seal part 12 integrally formed with the outer peripheral lip 10 is provided with leaving a space 11 above the outer peripheral surface of the insert metal 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic buffer for preventing oil and gas in a cylinder or an outer shell from leaking to the outside by slidingly contacting a piston rod and for preventing external dust from entering the cylinder. TECHNICAL FIELD The present invention relates to an oil seal for a container and a molding method thereof.

[0002]

2. Description of the Related Art Generally, a hydraulic shock absorber used as a suspension system for a vehicle is provided with an oil seal at the end of a cylinder that is in sliding contact with a piston rod to prevent oil and gas in the cylinder from leaking and to prevent dust from the outside. Prevents intrusion.

For example, as shown in FIG. 3, a conventional hydraulic shock absorber has a bearing 3 provided at the outer ends of a cylinder 1 and an outer shell 2 and an oil seal 4 provided outside the bearing 3. A piston rod 5, which is movably inserted into the cylinder 1 via a piston, slidably penetrates the bearing 3 and the oil seal 4. As shown in FIGS. 3 and 4 (A), the oil seal 4 includes a disk-shaped insert metal 6, an inner peripheral lip 9 including a dust lip 7 and an oil lip 8 provided on the inner periphery of the insert metal 6, It is composed of an outer peripheral lip 10 provided on the lower surface on the outer peripheral side of the insert metal 6, the dust lip 7 prevents the intrusion of dust from the outside, and the oil lip 8 prevents the leakage of oil in the oil chamber 11 of the cylinder 1. The outer peripheral lip 10 prevents gas from leaking from the reservoir R in the outer shell 2.

The insert metal 6 and the outer peripheral lip 10 are supported on the bearing 3, and the upper portion on the outer peripheral side of the insert metal 6 is bent by crimping the upper end portion of the outer shell 2 to form the upper end portion of the outer shell 2 and the bearing 3. Being held in. On the other hand, the conventional oil seal 4 is molded using the mold shown in FIG.

As shown in FIG. 5, the method for molding the oil seal by this mold is as follows. A lower mold A, an annular intermediate mold B fitted to the outer periphery of the lower mold A, and a lower mold. For an inner peripheral lip consisting of a lower lip die A and an upper die die C, each of which includes a die lip A and an oil lip. The annular grooves a and b are formed, and the annular groove c for the outer peripheral lip is formed in the intermediate mold B and the upper mold C, and the insert is inserted into the intermediate mold B while being supported by the lower mold A. The metal 6 is inserted, the molding material rubber is placed on the upper side of the insert metal 6, and the upper mold C is fitted and pressed from above the material rubber to push the material rubber into the annular grooves a, b. , C, the inner peripheral lips 9 are respectively formed on the inner peripheral side and the outer peripheral side of the insert metal 6.
And the outer peripheral lip 10 are pressure-bonded.

[0006]

However, the above-mentioned conventional method for forming an oil seal and the oil seal obtained thereby have the following problems, and their improvement is desired.

First, as shown in FIG. 5, the inner diameter of the intermediate mold B and the outer diameter of the insert metal 6 are substantially equal to each other, and in this state, the insert metal 6 is inserted into the inner circumference e of the intermediate mold B from above. Therefore, the outer periphery of the insert metal 6 may come into contact with the inner periphery e of the intermediate mold B during this insertion. Therefore,
Since both are made of a hard material such as metal, they are scratched when they come into contact with each other. When such a state is repeated, the damaged portion of the inner circumference e of the intermediate mold B gradually becomes large,
Outer peripheral lip 1 in oil seal 4 that is molded later
A scar is transferred to the outer surface of 0. Then, as shown in FIG. 3, when the oil seal 4 is assembled as it is, a slight gap caused by the scar is generated between the outer peripheral lip 10 and the outer shell 2, and there is a problem that gas leaks from this portion. ..

Secondly, a part of the material rubber pressed at the time of molding the oil seal may go around the outer periphery of the insert metal 6 and a thin rubber film may remain on the outer periphery of the insert metal 6. If the oil seal 4 is assembled in this state as shown in FIG. 3, the remaining rubber film is pressed when the upper end of the outer shell 2 is crimped, and there is no place to go, so it overflows to the outer upper surface of the insert metal 6. Come on. The overflowed rubber becomes foreign matter and may enter between the inner peripheral lip 9 and the piston rod 5, which causes a problem of oil leakage. In order to eliminate this inconvenience, conventionally, as shown in FIGS. 4B and 4C, a notch step 6a and a chamfered slope 6b are respectively formed in the upper part on the outer peripheral side of the insert metal 6, and the overflowed rubber is It is housed in the space formed by the notched stepped portion 6a and the chamfered inclined portion 6b so as not to fly out as foreign matter. However, in this case, the cutting and chamfering of the insert metal 6 are required, and there is a problem that the cost increases accordingly.

Therefore, an object of the present invention is to prevent damage to the mold during molding, and as a result, to prevent transfer of scars to the outer peripheral lip, and the rubber wrapping around the outer periphery of the insert metal overflows as foreign matter to the outside. It is an object of the present invention to provide an oil seal and a method for molding the same that can prevent the occurrence of the above.

[0010]

In order to achieve the above object, the means of the oil seal of the present invention is a disk-shaped insert metal, and an upper dust lip and a lower oil provided on the inner peripheral side of the insert metal. An oil seal consisting of an inner peripheral lip consisting of a lip and an outer peripheral lip provided on the lower surface of the insert metal on the outer peripheral side is integrally formed with the outer peripheral lip while leaving an arbitrary space above the outer peripheral surface of the insert metal. It is characterized in that a seal portion is provided.

Similarly, the means for forming the oil seal according to the present invention comprises a lower die, an annular intermediate die fitted to the outer periphery of the lower die, and an intermediate die between the lower die and the middle die. An upper die that fits above the die is provided, and an annular groove for an inner peripheral lip consisting of a dust lip and an oil lip is formed in the lower die and the upper die to form an intermediate die. Form an annular groove for the outer peripheral lip on the upper mold and the upper mold, insert the insert metal into the intermediate mold while being supported by the lower mold, place the molding material rubber on the upper side of the insert metal, By fitting and pressing the upper mold from above the material rubber to cause the material rubber to flow into each of the annular grooves, the inner lip and the outer lip of the insert metal on the inner circumference side and the outer circumference side, respectively. In the method of forming an oil seal that crimps and A ring-shaped projection on one side, insert the insert metal into the inner circumference of the above-mentioned projection, and provide an arbitrary annular gap between the outer circumference of the insert metal and the inner circumference of the intermediate mold, and press the upper mold. At the same time, the raw material rubber is allowed to flow into each of the annular grooves, and at the same time a portion of the raw material rubber is allowed to flow into the gap to provide a rubber seal portion on the outer peripheral surface of the insert metal and form a space at a position corresponding to the protrusion. It is characterized by.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIG.
A description will be given based on FIG.

Like the conventional hydraulic shock absorber shown in FIG. 3, the oil seal according to the present invention is arranged on the outer upper part of the bearing 3 and fixed by caulking at the upper end of the outer shell 2. The oil seal prevents dust from entering from the outside, prevents oil from leaking in the cylinder 1, and prevents gas from leaking from the reservoir R.

The oil seal 4 is, as shown in FIG.
An inner peripheral lip 9 composed of a disc-shaped insert metal 6, an upper dust lip 7 and a lower oil lip 8 provided on the inner peripheral side of the insert metal 6, and an outer peripheral lip provided on the lower surface on the outer peripheral side of the insert metal 6. It consists of 10. According to the present invention, the outer peripheral lip 1 is formed while leaving an arbitrary space 11 above the outer peripheral surface of the insert metal 6.
It is characterized in that a seal portion 12 integrally formed with 0 is provided.

According to the oil seal 4, this is shown in FIG.
When the upper shell of the outer shell 2 is crimped by assembling as described above, the seal portion 12 is pressed. However, since a part of the seal portion 12 is accommodated in the space 11, the foreign matter is further exposed to the outside. It never overflows. Therefore, it is possible to prevent foreign matter from entering the inner peripheral lip 9 and leaking oil as in the conventional case.

Next, in order to mold the above oil seal 4, the mold shown in FIG. 2 is used. This mold is a modification of the conventional mold shown in FIG. 5 so that the space 11 and the seal portion 12 can be formed on the outer peripheral surface side of the insert metal 6. However, when using this mold, insert metal 6
The outer diameter of the insert metal 6 is slightly smaller than that of the conventional insert metal 6.

The method of molding the oil seal 6 is basically the same as the conventional one, the lower mold A, the annular intermediate mold B fitted to the outer periphery of the lower mold A, and the lower mold. A and an upper mold C that is fitted over the intermediate mold B are provided. Then, the lower mold A and the upper mold C are formed with annular grooves a and b for the inner peripheral lip 9 composed of the dust lip 7 and the oil lip 8, and the intermediate mold B and the upper mold C are formed. An annular groove c for the outer peripheral lip 10 is formed there. Thereby, the insert metal 6 is inserted into the intermediate mold B while being supported by the lower mold A, the molding material rubber is placed on the upper side of the insert metal 6, and the upper mold C is placed from above the material rubber. By fitting and pressing the material rubber, the material rubber is pressed into the annular grooves a, b,
The inner peripheral lip 9 and the outer peripheral lip 10 are pressure-bonded to the inner peripheral side and the outer peripheral side of the insert metal 6 by flowing into the c. Up to this point, it is the same as the conventional one, but in the present invention, an annular projection d is further formed below the inner circumference of the intermediate mold B, and the insert metal 6 having a smaller outer diameter dimension than the conventional one is inserted into the inner circumference of the projection d. Then, an arbitrary annular gap e is provided between the outer periphery of the insert metal 6 and the inner periphery of the intermediate die B, and when the upper die C is pressed, a part of the material rubber is made to flow into the gap e. A rubber seal portion 12 is provided on the outer peripheral surface of the insert metal 6 and a space 11 is formed at a position corresponding to the protrusion d. In this case, the outer diameter of the insert metal 6 is smaller than that of the conventional one, so that the insert metal 6 does not come into contact with the inner circumference of the intermediate mold B and does not cause scratches therebetween.

The outer diameter of the insert metal 6 can be made substantially close to the outer diameter of the conventional insert metal 6 by interposing the rubber seal portion 12.
The sealing effect between the insert metal 6 and the insert metal 6 can be enhanced. Since the material comb does not enter the portion corresponding to the protrusion d, the space 11 is formed above the outer surface of the insert metal 6 when taken out from the mold.

A rubber film may slightly invade between the inner circumference of the projection d and the outer circumference of the insert metal 4 during molding, but this rubber film is housed in the space 11 during caulking and overflows to the outside. It never comes out.

The groove f shown in FIGS. 2 and 5 is for accommodating the excess rubber that could not be accommodated in the annular grooves a, b, c and the space e when a large amount of material rubber is placed. In the above embodiment, the outer diameter of the insert metal 6 is smaller than the conventional one, but conversely, the intermediate die B may be larger in diameter than the conventional one.

[0021]

The present invention has the following effects.

1) According to the invention of the oil seal of claim 1, since the seal portion is provided on the outer peripheral surface of the insert metal while leaving a space above, the seal is provided even when the outer peripheral side of the insert metal is caulked by the outer shell. A part of the part is accommodated in the space, and as a result, it is prevented that the part overflows and pops out as a foreign substance. Therefore, it is possible to prevent foreign matter from entering the inner lip and leaking oil.

2) Similarly, the seal portion seals the gap between the outer circumference of the insert metal and the inner circumference of the outer shell when assembled to the hydraulic shock absorber integrally with the outer circumference lip, and cooperates with the outer circumference lip to prevent gas leakage. It can be prevented more reliably.

3) According to the invention of the oil seal molding method of claim 2, the insert metal is inserted into the inner circumference of the projection, and an annular gap is provided between the main inner circumference of the intermediate mold and the outer circumference of the insert metal. Therefore, when the insert metal is inserted into the intermediate mold, there is no contact between the outer circumference of the insert metal and the inner circumference of the intermediate mold, and both are not damaged to leave a scar. Therefore, the scar is not transferred to the outer surface of the molded outer peripheral lip, and the gas leakage due to the scar can be prevented.

4) Similarly, according to the above molding method, a space is automatically formed above the outer periphery of the insert metal,
Since it is possible to accommodate a part of the seal part that is pressed during crimping in this space, it is not necessary to form a notched step part in the insert metal or to provide a chamfered inclined part as in the conventional case, so the number of processing steps is reduced. Can be omitted, processing equipment is not required, workability can be improved, and cost can be reduced.

[Brief description of drawings]

FIG. 1 is a half sectional view of an oil seal according to the present invention.

FIG. 2 is a half sectional view of a mold used in the method for molding an oil seal according to the present invention.

FIG. 3 is a partially enlarged vertical sectional front view of a conventional hydraulic shock absorber.

4A, 4B, and 4C are half cross-sectional views of a conventional oil seam.

FIG. 5 is a half sectional view of a mold used for molding a conventional oil seal.

[Explanation of symbols]

4 oil seal 6 insert metal 7 dust lip 8 oil lips 9 Inner lip 10 outer lip 11 space 12 Seal part a, b, c annular groove d protrusion e Annular gap A lower mold B Intermediate mold C Upper mold

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Etsuro Nakata             2-4-1, Hamamatsucho, Minato-ku, Tokyo World Trade             Yasu Center Building Kayaba Industry Co., Ltd. F-term (reference) 3J006 AB03 AB11 AC00                 3J069 AA50 CC19

Claims (2)

[Claims] 1. An inner peripheral lip composed of a disc-shaped insert metal, an upper dust lip and a lower oil lip provided on the inner peripheral side of the insert metal, and an outer peripheral lip provided on the outer peripheral lower surface of the insert metal. An oil seal comprising the insert metal, wherein a seal portion integrally formed with the outer peripheral lip is provided on the outer peripheral surface of the insert metal while leaving an arbitrary space above. 2. A lower mold, an annular middle mold fitted to the outer periphery of the lower mold, and a lower mold and an upper mold fitted above the middle mold. An annular groove for an inner peripheral lip consisting of a dust lip and an oil lip is formed in the lower die and the upper die, and an annular groove for an outer peripheral lip is formed in the intermediate die and the upper die. The insert metal is inserted into the intermediate mold while being supported by the lower mold, the molding material rubber is placed on the upper side of the insert metal, and the upper mold is fitted from above the material rubber. In the method for forming an oil seal, the material rubber is caused to flow into each of the annular grooves by being pressed to press the inner peripheral lip and the outer peripheral lip to the inner peripheral side and the outer peripheral side, respectively. An annular protrusion is formed below the inner circumference of the mold, and the insert metal is When inserted into the inner circumference of the raised metal, an arbitrary annular gap is provided between the outer circumference of the insert metal and the inner circumference of the intermediate mold, and when the upper mold is pressed, the material rubber is caused to flow into the respective annular grooves. At the same time, a part of the material rubber is made to flow into the gap to provide a rubber seal portion on the outer peripheral surface of the insert metal, and a space is formed at a position corresponding to the protrusion.