JPH0628429U - Reciprocating oil seal - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a reciprocating oil seal having a simple structure and improved in sealing performance against intrusion of fluid on the atmosphere side into the sealing side and following performance with respect to shaft eccentricity. A seal lip 7 for sealing at least the fluid on the sealed side O and a dust lip 16 for sealing the fluid on the atmospheric side A
In the reciprocating oil seal 15 having the following, from the dust lip tip portion 17 of the dust lip 16 to the sealing side O,
At least one annular convex portion 18 having a predetermined tightening margin is provided.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a reciprocating oil seal, and more particularly to a reciprocating oil seal that prevents leakage of sealing fluid from the reciprocating portions of two members that move relative to each other in the axial direction.

[0002]

[Prior art]

 Generally, reciprocating oil seals for preventing leakage of sealed fluid such as oil are often used in reciprocating mechanisms such as shock absorbers used in automobiles, motorcycles, various machines and the like.

FIG. 6 shows an essential part of a general reciprocating oil seal 1 of this type, which is designed to be mounted between a housing 2 and a rod 3 which reciprocate with each other. . In this reciprocating oil seal 1, a seal main body 5 made of a rubber-like elastic body or the like is integrally fixed to an annular reinforcing ring 4 made of metal or the like and having a substantially L-shaped cross section. The seal body 5 is formed with an outer peripheral surface 6 which is located on the outer peripheral side of the reinforcing ring 4 and has an appropriate tightening margin for the housing 2, and is located inside the reinforcing ring 4 of the seal body 2. The seal lip 7 extends to the upper sealed side O in the figure to prevent leakage of a desired sealing fluid, and the seal lip 7 extends to the lower atmospheric side A in the figure to seal the dust or muddy water on the atmospheric side. A dust lip 8 is formed to prevent entry into the area.

On the inner peripheral surface of the upper end portion of the seal lip 7 in the figure, a main lip tip portion 9 having a predetermined tightening margin is formed toward the inside, and below the main lip tip portion 9 is tightened. An auxiliary lip tip portion 10 is formed which has a tightening margin smaller than the margin and has an apex toward the rod 3 having a substantially triangular cross section or an apex. Then, a desired spring 12 is mounted in a mounting groove 11 formed in a circumferential direction at a position corresponding to the main lip tip portion 9 on the outer peripheral surface of the seal lip 7, and the main lip tip portion 9 and the auxiliary lip are attached. The tip portion 10 and the tip portion 10 are radially inwardly tightened to the rod 3 by a desired tightening force. Further, on the inner peripheral surface of the lower end portion of the dust lip 8 in the drawing, a dust lip tip portion 13 having a predetermined tightening margin toward the inside is formed.

[0005]

[Problems to be solved by the device]

 However, in the above-described conventional reciprocating oil seal 1, in the mounted state, the dust lip 8 hits the rod 3 with a large contact area in the axial direction, and the dust lip tip portion 13 of the dust lip 8 contacts the dust lip 8. Since the straining force cannot be concentrated, the straining force is dispersed in the axial direction of the rod 3, and the sealing property (dust resistance) against the ingress of dust or muddy water on the atmospheric side into the sealing side and the axial eccentricity of the rod 3 are generated. There was a problem that it was inferior to the following ability.

In order to solve such a problem, as shown in FIG. 7, a reciprocating oil seal 1a in which a spring 14 is attached to the outer peripheral portion of the dust lip 8a may be used. When the oil seal 1a is used, the number of parts is increased and the size of the dust lip 8a is increased. This not only increases the economic burden but also requires the recent miniaturization and space saving. There was a problem of going backwards.

The present invention has been made in view of these points, overcomes the problems of the conventional ones described above, and has a simple structure, and has a sealing property against the intrusion of the fluid on the atmosphere side into the sealing side. Another object of the present invention is to provide a reciprocating oil seal having improved followability with respect to shaft eccentricity.

[0008]

[Means for Solving the Problems]

 In order to achieve the above object, the reciprocating oil seal of the present invention is a reciprocating oil seal having at least a sealing lip for sealing a fluid on the sealing side and a dust lip for sealing a fluid on the atmosphere side. The present invention is characterized in that at least one annular convex portion having a predetermined tightening margin is provided on the sealing side from the tip of the dust lip.

[0009]

[Action]

 According to the reciprocating oil seal of the present invention having the above-described structure, by forming an annular convex portion having a predetermined tightening margin from the dust lip tip portion of the dust lip to the dust lip, It is possible to reliably prevent a large contact area in the axial direction of the rod and to concentrate the tightening force on the tip of the dust lip of the dust lip, and to prevent dust or muddy water from entering the sealed side. The sealability (dust resistance) and the followability to the shaft eccentricity can be improved.

[0010]

【Example】

 An embodiment of the present invention will be described below with reference to FIGS. It should be noted that the same or corresponding configurations as those of the conventional one described above are denoted by the same reference numerals in the drawings, and the description thereof will be omitted.

FIG. 1 is a vertical cross-sectional view showing a main part of a reciprocating oil seal according to the present invention.

As shown in FIG. 1, a reciprocating oil seal 15 according to the present embodiment includes a seal main body 5 made of a rubber-like elastic body or the like on an annular reinforcing ring 4 having a substantially L-shaped cross section made of metal or the like. Are fixed together. The seal body 5 is formed with an outer peripheral surface 6 which is located on the outer peripheral side of the reinforcing ring 4 and has an appropriate tightening margin with respect to the housing 2, and is located inside the reinforcing ring 4 of the seal body 5. The seal lip 7 extends to the upper sealed side O in the figure to prevent the leakage of desired sealing fluid, and the seal lip 7 extends to the lower atmospheric side A in the figure to seal the dust or muddy water on the atmospheric side. A dust lip 16 is formed to prevent the entry of the dust lip 16.

On the inner peripheral surface of the upper end portion of the seal lip 7 in the figure, a main lip tip portion 9 having a predetermined tightening margin toward the inside is formed, and at a predetermined position below the main lip tip portion 9, a main lip tip portion is formed. The auxiliary lip tip portion 10 has a tightening margin smaller than that of No. 9 and has a substantially triangular cross-section having an apex toward the rod 3 or a rounded apex. Then, a desired spring 12 is mounted in a mounting groove 11 formed in a circumferential direction at a position corresponding to the main lip tip 9 on the outer peripheral surface of the seal lip 7, and the main lip tip 9 and The auxiliary lip tip 10 and the auxiliary lip tip 10 are tightened radially inward by a desired tightening force.

Further, a dust lip tip portion 17 having a predetermined tightening margin is formed on the inner peripheral surface of the lower end portion of the dust lip 16 in the figure, and the dust lip tip portion 17 of the dust lip 16 is At a predetermined position on the sealing side O on the upper side in the drawing, one convex portion 18 having a substantially triangular cross section is formed, which has an apex toward the annular rod 3 having an appropriate interference.

The position, shape, number and the like of the convex portions 18 formed on the dust lip 16 may be any as long as the tightening force can be concentrated on the dust lip tip portion 17 of the dust lip 16 in the mounted state. The present invention is not limited to this example.

Further, as shown in FIG. 2, it is also possible to form a mounting groove 11 in the dust lip 16a and form a reciprocating oil seal 15a in which the spring 14 is mounted. However, in this case, there are problems that the number of parts increases and the overall size of the dust lip 16a increases, the economic burden increases, and it is not suitable for downsizing and space saving.

Next, the operation of the reciprocating oil seal of the present embodiment having the above-described configuration will be described by exemplifying a concrete experimental example.

Experimental Example 1 A comparative experiment was carried out on the distribution of the tension force of the dust lip in the mounted state of the reciprocating oil seal of this example and the conventional reciprocating oil seal.

Experimental results are shown in FIGS. 3A and 3B.

FIG. 3 is an explanatory view showing the distribution of the tightening force of the dust lip of the present embodiment in the mounted state, and the distribution of the tightening force of the dust lip 16 of the embodiment shown in FIG. It was found that the axial range of the tension force of the dust lip tip portion 17 is narrow and the magnitude of the tension force is large as compared with FIG. 8B showing the distribution of the tension force of the conventional dust lip 8.

That is, the fact that the range of the tightening force of the dust lip tip portion 17 of the dust lip 17 of the reciprocating oil seal 15 of the present embodiment in the rod axial direction is narrow means that the tension force is concentrated on the dust lip tip portion 17. This means that the sealability (dust resistance) against the ingress of dust or muddy water on the atmosphere side A into the seal side O can be reliably improved, and stable sealability can be maintained for a long period of time. Produce an effect. In addition, the increased tightening force has the effect of reliably improving the followability with respect to the axial eccentricity of the rod 3.

Hereinafter, an experimental example will be illustrated with respect to the sealing property of the reciprocating oil seal of this embodiment and the followability with respect to the shaft eccentricity.

Experimental Example 2 A reciprocating oil seal, which is a sample, is attached to a shock absorber (not shown), mud is placed on the atmosphere side, and the amount of entry into the sealed side of the mud is investigated under the same conditions. A comparative test of the dust tight sealability was performed.

As the reciprocating oil seal to be the sample, the reciprocating oil seal 1 (FIG. 6) having the conventional dust lip 8 is used as the sample A, and the reciprocating oil seal 1 having the spring 14 in the conventional dust lip 8 a is used for the reciprocating motion. The oil seal 1a (FIG. 7) was used as the sample B, the reciprocating oil seal 15 having the dust lip 16 of this embodiment (FIG. 1) was used as the sample C, and the reciprocating oil having the spring 19 in the dust lip 16a of this embodiment was used. The seal 15a (FIG. 2) was used as sample D. Then, one reciprocation of the shock absorber rod 3 was defined as one cycle, and the amount of entering muddy water at 1 million cycles and 2 million cycles was calculated.

FIG. 4 shows the test results. As is clear from the test results, the reciprocating oil seal 15 (Sample C) of the present embodiment has a remarkably improved sealing property as compared with the conventional reciprocating oil seal 1 (Sample A), and also has a dust lip. It was found that the reciprocating oil seals 1a and 15a (sample B and sample D) having springs had the same sealing performance.

Experimental Example 3 A reciprocating oil seal, which is a sample, is attached to a shock absorber (not shown), and the relationship between the axial eccentricity of the rod and the rod speed that can be followed is investigated. I did.

As the reciprocating oil seal used as the sample, the reciprocating oil seal 1 (FIG. 6) having the conventional dust lip 8 was used as the sample A, and the conventional dust lip 8a was replaced by a spring. The reciprocating oil seal 1a (FIG. 7) having 14 is the sample B, and the reciprocating oil seal 15 (FIG. 1) having the dust lip 16 of this embodiment is the sample C. The dust lip 16a of this embodiment has a spring. A reciprocating oil seal 15a (FIG. 2) having 14 was used as Sample D.

FIG. 5 shows the test results. In FIG. 5, the region below the line segment of each sample shows the region that can follow the axial eccentricity, and the upper side shows the region that cannot follow it. As is clear from this test result, the reciprocating oil seal 15 (Sample C) of the present embodiment has a significantly improved followability with respect to shaft eccentricity as compared with the conventional reciprocating oil seal 1 (Sample A). It was found that the reciprocating oil seal 1a (sample B) having the spring 14 in the dust lip 8a has the same followability to the shaft eccentricity. Further, it was found that if the reciprocating oil seal 15a (Sample D) having the spring 14 is used for the dust lip 16a of this embodiment, the followability with respect to the shaft eccentricity can be further improved.

It should be noted that the present invention is not limited to the above-described embodiments, and various modifications can be made as necessary.

[0030]

[Effect of device]

 As described above, according to the reciprocating oil seal of the present invention, the tightening force can be concentrated on the tip of the dust lip of the dust lip, and the sealing performance against the ingress of dust or muddy water on the atmosphere side into the sealing side ( (Dust resistance) and the followability with respect to rod axial eccentricity can be reliably improved.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a main part of an embodiment of a reciprocating oil seal according to the present invention.

FIG. 2 is a view similar to FIG. 1 showing essential parts of another embodiment of the reciprocating oil seal according to the present invention.

FIG. 3 is an explanatory view showing the distribution of the tension force of the dust lip in the mounted state, a shows the distribution of the tension force of the dust lip of the oil seal for reciprocation according to the present invention, and b is the conventional oil seal for reciprocation. Showing the distribution of the tense force of dust lip

FIG. 4 is a diagram showing the test results of the dust tight sealability.

FIG. 5 is a diagram showing the relationship between the axial eccentricity of the rod and the followable rod speed.

FIG. 6 is a vertical cross-sectional view showing a main part of an example of a conventional reciprocating oil seal.

FIG. 7 is a view similar to FIG. 6 showing essential parts of another embodiment of a conventional reciprocating oil seal.

[Explanation of symbols]

 2 housing 3 rod 4 reinforcing ring 5 seal body 6 outer peripheral surface 7 seal lip 9 main lip tip 10 auxiliary lip tip 11 mounting groove 12 spring 14 spring 15, 15a reciprocating oil seal 16, 16a dust lip 17 dust lip tip 18 convex

Claims (1)

[Scope of utility model registration request] 1. A reciprocating oil seal having at least a seal lip for sealing fluid on the sealed side and a dust lip for sealing fluid on the atmosphere side, wherein a predetermined amount is provided on the sealed side from a dust lip tip portion of the dust lip. An oil seal for reciprocating motion, comprising at least one annular convex portion having a tightening margin.