JPH0738779U - Damper seal structure - Google Patents

Abstract

(57) [Summary] [Purpose] Not only can it deal with vibrations due to shimmies and kickbacks that tend to increase, but it is also possible to achieve prescribed sealing performance while enabling miniaturization and weight reduction. To do. An oil seal 6 for inserting a tip end side of a rod body 2 which is inserted into and retractable from a cylinder body 1 has a dust lip portion 6a and an oil lip portion which slidably contact the inner peripheral surface of the rod body 2 with the outer periphery of the rod body 2. 6b, and a lip portion 6c that exerts a labyrinth effect with the adjacent member (7) on the outer peripheral surface thereof, and a protruding portion 6d that constitutes a spring is provided on the outer peripheral side of the upper end thereof. Let's have it.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to improvement of a seal structure of a damper used as a steering damper or the like.

[0002]

[Prior art and its problems]

 Generally, in the steering system of a vehicle, it is said that vibrations due to shimmy, kickback, etc. do not propagate to the steering, and as a damper for such a steering damper, for example, due to recent demands for downsizing and weight reduction, In some cases, a single-cylinder structure damper as shown in FIG. 2 is used.

In the damper, a piston 3 slidably accommodated in the cylinder body 1 is continuously provided at the tip of a rod body 2 whose tip side is inserted into the cylinder body 1 so that the tip side can be retracted. A rod side chamber A and a piston side chamber B are defined in the cylinder body 1 by 3, and a free piston 4 is arranged in the piston side chamber B, and a gas chamber G is formed on the back rear side of the free piston 4. I am trying.

Then, the gas pressure in the gas chamber G urges the piston 3 to rise in the cylinder body 1, that is, the rod body 2 tends to project from the cylinder body 1 in the extension side. Is going to be.

The piston 3 is provided with a relief valve 3a that releases the hydraulic pressure of the rod side chamber A to the piston side chamber B, and a predetermined amount is set when the hydraulic oil flows between the rod side chamber A and the piston side chamber B. The damping valve 3b for generating the damping force is provided.

On the other hand, in the damper, as a seal structure for cutting off the inside of the cylinder body 1 from the outside so as to maintain a so-called hydraulic pressure, it is arranged on the inner periphery of the opening end portion which is the upper end portion of the cylinder body 1 in the figure. A seal structure is adopted in which an oil seal 6 is disposed so as to be adjacent to a so-called outer side which is an upper side in the drawing, a rod guide 5 which is a bearing for penetrating the rod body 2 in a central portion.

In the above-mentioned seal structure, a space is formed between the rod guide 5 and the oil seal 6 because the oil seal 6 has a special shape. The space is used as the oil sump chamber R.

In addition, the oil seal 6 has an upper dust lip portion 6a and a lower oil lip portion 6b on the inner peripheral surface thereof.

Therefore, in the above-described seal structure, the hydraulic pressures in the cylinder body 1, that is, in the rod side chamber A and the inside of the oil seal 6, that is, in the oil sump chamber R are substantially equal to each other. The tightening margin of the oil seal 6, that is, the sealing performance is set based on the gas pressure in the gas chamber G, so that oil leakage at the so-called seal portions, that is, the dust lip portion 6a and the oil lip portion 6b is prevented. Will be.

However, in recent vehicles, there is a tendency that the tire size becomes large and the engine power becomes large, so that the vibrations that affect the steering due to shimmy, kickback, etc., tend to increase. .

Therefore, it has been proposed to increase the damping force of the damper to effectively prevent the vibration due to shimmy or kickback, which tends to increase, but as described above, the damper is downsized and lightweight. In the current situation in which the reduction of pressure is required, there is a fear that the sealing performance of the oil seal 6 may not be sufficient only by increasing the damping force.

The present invention was devised in view of the above-mentioned circumstances, and its purpose is, of course, to deal with vibrations due to shimmy and kickback that tend to increase. Another object of the present invention is to provide a damper seal structure that is optimal for use in a damper that can achieve a predetermined sealing performance while enabling downsizing and weight reduction.

[0013]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the structure of the present invention is applied to a cylinder body through an oil seal in which a tip end side of a rod body which is inserted into and retractable from a cylinder body is arranged on an inner circumference of an opening end side of the cylinder body. In the seal structure of the damper inserted into the body, the oil seal has a dust lip portion and an oil lip portion that are in sliding contact with the outer circumference of the rod body on the inner peripheral surface of the oil seal, and the outer peripheral surface of the oil seal is adjacent to the adjacent member. It is assumed that it has a lip portion that exerts a labyrinth effect between them, and that it has a protruding portion that constitutes a spring on the outer peripheral side of its upper end.

The projecting portion is positioned on the outer peripheral side of the dust lip portion, is formed in an annular shape, and forms an annular chamber for forming an annular air spring on the outer periphery thereof. It is assumed that the protruding portion is formed in the shape of a protrusion and the protruding portion itself constitutes a spring.

[0015]

[Action]

 Therefore, when the high pressure from the cylinder body, that is, from the rod side chamber propagates to the oil sump chamber through between the inner circumference of the rod guide and the outer circumference of the rod body, the oil sump chamber is expanded and protrudes. A spring effect is obtained by the portion, and the high pressure is reduced.

As a result, an excessive load does not act on the oil seal, the pressure resistance of the oil seal is improved, and the durability of the oil seal is improved.

Further, when the cylinder body, that is, the rod side chamber becomes the low pressure side, the hydraulic pressure in the oil sump chamber is reduced, and the oil sump chamber and the oil seal are restored to the old state.

[0018]

【Example】

 The present invention will be described below based on the drawings. As shown in FIG. 1, a damper according to an embodiment of the present invention is basically a damper as a conventional example (see FIG. 2). ).

Therefore, the same portions of the configuration are denoted by the same reference numerals in the drawings except where necessary, and the description thereof will be omitted. The features of this embodiment will be described below. I will explain mainly.

That is, the damper of the embodiment shown in FIG. 1 is set to have a seal structure having an oil seal 6 on the inner periphery of the opening end side which is the upper end side of the cylinder body 1 in the figure.

In the illustrated example, a cap member 7 is continuously provided at the upper end of the cylinder body 1, and the tip end side of the rod body 2 is inserted through the central opening 7 a of the cap member 7 to form a cylinder. The rod guide 5 is guided inside the body 1 and is arranged on the inner circumference of the cap member 7 together with the oil seal 6.

In this embodiment, the oil seal 6 is reinforced by having a cored bar 61 on the outer peripheral side thereof, while having a dust lip portion 6a on the upper end side of the inner peripheral surface thereof. The oil lip portion 6b is provided on the lower end side of the inner peripheral surface thereof, and the garter spring 62 is provided on the outer periphery of the oil lip portion 6b.

The above-described configuration of the oil seal 6 is a well-known configuration in this type of oil seal, but the oil seal 6 is novel in that it is also configured as follows in addition to the above configuration. It has its own characteristics.

That is, in this embodiment, the oil seal 6 has a lip portion 6c on the outer peripheral surface thereof, and a protruding portion on the upper end side thereof, that is, on the outer peripheral side of the dust lip portion 6a. 6d.

Due to the formation of the lip portion 6c on the outer peripheral surface, a labyrinth effect is exerted between the outer periphery of the oil seal 6 and another member adjacent thereto, that is, the inner periphery of the cap member 7. Therefore, the so-called inconvenience that the pressure in the oil sump chamber R escapes between the outer circumference of the oil seal 6 and the inner circumference of the cap member 7 is eliminated.

On the other hand, the above-mentioned protrusion 6d on the upper end side constitutes a so-called spring in the present invention, and in the illustrated example, it is formed in an annular shape, and the protrusion 6d is formed. When the upper end is adjacent to the inner circumference of the cap member 7, which is another member, an annular chamber R1 is formed between the outer circumference of the projection 6d and the inner circumference of the cap member 7. .

As a result, the projection 6d has a condition that the upper end of the projection 6d comes into pressure contact with the inner circumference of the cap member 7. However, the projection 6d has an annular air spring on the outer circumference side thereof. As described above, a so-called spring is configured.

Therefore, in the damper according to this embodiment having the oil seal 6 formed as described above, during the extension side stroke in which the piston 3 rises inside the cylinder body 1, The hydraulic pressure, that is, the high pressure from the rod side chamber A is propagated to the piston rod oil sump chamber R through between the inner circumference of the rod guide 5 and the outer circumference of the rod body 2. At this time, the oil seal 6 is capped. It tends to rise in the member 7.

When the oil seal 6 rises in the cap member 7, the oil reservoir R is expanded in the axial direction of the cylinder body 1, while the protruding portion 6d is moved from the annular chamber R1. Since the air spring is provided, the hydraulic pressure propagated from the cylinder body 1 side to the oil reservoir R, that is, the high pressure is reduced, and an excessive load is not applied to the oil seal 6.

Therefore, the pressure resistance of the oil seal 6 is improved and the durability of the oil seal 6 itself is improved.

When the damper reverses from the expansion side stroke to the compression side stroke, the rod side chamber A becomes a lower pressure side than the piston side chamber B in the cylinder body 1, and accordingly, the oil sump The oil pressure in the chamber R is reduced, and the oil seal 6 also tends to descend in the cap member 7, so that the oil sump chamber R and the oil seal 6 are restored to the old state.

With the above-mentioned configuration, the intended purpose can be achieved only by improving the oil seal 6, no other member is required, and the diameter of the portion where the oil seal 6 is distributed is increased. There is no need to change the design, such as the steering damper disclosed in Japanese Utility Model Publication No. Sho 64-29547, even if the intended purpose can be achieved, the number of parts increases and the oil seal 6 Inconveniences such as increasing the outer diameter of the portion where is distributed will not be brought about.

As described above, the oil seal 6 according to the present invention has the protruding portion 6d and the protruding portion 6d formed in an annular shape so that the upper end side thereof has an annular air spring. However, the so-called spring may be formed on the protrusion 6d as follows.

That is, in the above-described embodiment, the protrusion 6d is formed in an annular shape, but instead of this, although not shown, the protrusion 6d protrudes at an appropriate interval in the circumferential direction. Alternatively, the protrusion 6d formed in the protruding shape may be a spring.

When the projecting portion 6d is formed in a projecting shape, the chamber R1 is not formed, but the projecting portion 6d itself constitutes a spring. Therefore, even in this embodiment, even in this embodiment, Similarly to the case, it is possible to reduce the high pressure transmitted to the oil sump chamber R and reduce the excessive load on the oil seal 6.

In the case of this embodiment, the oil seal 6 is most suitable when it is made of a hard rubber having a large spring constant, and in the embodiment described above, a soft rubber having a small spring constant is used. It is most suitable when the oil seal 6 is formed.

The above description has been made with reference to the case where the damper of this embodiment is used as a steering damper. However, according to the configuration of the present invention, for example, in the damper of the embodiment, the piston 3 and It is needless to say that even a steering damper having a pressure side base valve provided between it and the free piston 4 or another vibration damping damper can be implemented, and the action and effect at that time are not different.

[0038]

[Effect of device]

 As described above, according to the present invention, the high pressure from the cylinder body reaching the oil sump chamber through the inner circumference of the rod guide and the outer circumference of the rod body causes the expansion and expansion of the oil sump chamber in the oil sump chamber. Since the spring effect in the oil seal lowers the pressure, an excessive load is not applied to the oil seal. Therefore, the pressure resistance of the oil seal is improved, the durability of the oil seal is improved, and the generated damping is reduced. It is possible to provide a damper that can be set to increase the force and effectively cope with vibration due to shimmy or kickback, which tends to increase, while reducing size and weight. There is.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a damper according to an embodiment of the present invention.

FIG. 2 is a vertical sectional view showing a damper as a conventional example.

[Explanation of symbols]

 1 Cylinder body 2 Rod body 3 Piston 4 Free piston 5 Bearing rod guide 5a Volume chamber 6 Oil seal 8 Pressure compensator A Rod side chamber B Piston side chamber G Gas chamber R Oil sump chamber

Claims (1)

[Scope of utility model registration request] 1. A damper seal structure in which a tip end side of a rod body that is inserted into and retracted from a cylinder body is inserted into the cylinder body through an oil seal disposed on an inner circumference of an opening end side of the cylinder body. In the above, the oil seal has a dust lip portion and an oil lip portion that are in sliding contact with the outer circumference of the rod body on the inner peripheral surface thereof, and a lip portion that exerts a labyrinth effect between the adjacent member on the outer peripheral surface thereof. The damper seal structure is characterized in that