JPH09170640A - Seal structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make, for example, the utilization to a shaft seal structure part in a hydraulic buffer most suitable, by that a seal can display a prescribed seal function perfectly when a seal whose outer periphery is closely contacted with the inner periphery of the opening end side of a cylinder body is stored in a seal storing part formed in the outer periphery side of a bearing main body formed by press working. SOLUTION: The diameter direction section of a seal storing part S formed on the outer periphery of a bearing main body 10 for shaft sealing the opening end side of a cylinder body 3 is composed by being set to a trapezoid whose lower side is a short side and upper side is long side and also outer periphery side is a vertical side and inner periphery side is a down slope side heading for an outer periphery side and also the diameter direction section of a seal 4, stored in a seal storing part S, whose outer periphery is closely contacted to the inner periphery of the opening end side of the cylinder body 3 is composed by being set to a shape which nearly coincides with the diameter direction section of the seal storing part S.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seal structure, and more particularly to an improvement in a seal structure in a shaft sealing structure of a hydraulic shock absorber or the like.

[0002]

2. Description of the Related Art For example, in a hydraulic shock absorber formed in a double cylinder type, a piston rod can be slid on a shaft portion while closing an opening end side of an outer cylinder which is a cylinder body and an opening end of a cylinder. There have been various proposals for the shaft sealing structure to be inserted, but in recent years, the bearing body that constitutes the shaft sealing structure is not formed of the conventional sintered steel but is formed by pressing a molded product of a steel plate or a steel pipe. There is a suggestion that it will consist of

That is, when the bearing body constituting the shaft-sealing structure is formed by pressing a molded product from a steel plate or a steel pipe, which is thinner than that of a sintered steel, it is lightweight. However, it is said that the cost of the shaft sealing structure itself can be reduced due to the reduction of the material cost, which can contribute to the reduction of the weight and the manufacturing cost of the hydraulic shock absorber.

The bearing main body is
The inner circumference is molded so as to have a rod body insertion hole for fixing the bush, which is in sliding contact with the outer circumference of the piston rod, on the inner circumference, while the outer circumference is on the outer circumference on the inner circumference on the opening end side of the outer cylinder. It is said that it is molded so as to have a seal accommodating portion for accommodating the seal to be closely contacted.

Incidentally, since the bearing body is formed by pressing, it is possible to set the seal accommodating portion in a relatively arbitrary shape when forming the seal accommodating portion.
Of course, it cannot be set to a shape that makes it impossible to perform so-called die cutting after press working.

On the other hand, the seal accommodating portion has conventionally been accommodated with a seal composed of an O-ring in many cases, that is, because it is easily available as a component, and the outer periphery of the seal is an outer cylinder. The air or oil containing oil from the reservoir chamber side formed on the inner peripheral side of the outer cylinder is allowed to come into contact with the inner peripheral side of the outer cylinder by being in close contact with the inner peripheral surface of the outer cylinder and the peripheral wall of the seal accommodating portion. It is said that it is prevented from leaking out through the outer circumference of the ring.

However, in the seal structure for accommodating the seal composed of the O-ring in the seal accommodating portion, in particular, the seal area required for so-called sealing between the inner circumference of the outer cylinder and the outer circumference of the O-ring. That is, it has been pointed out that a sufficient contact area between the two cannot be obtained, and therefore, empirically, it is difficult to easily realize a perfect sealed state.

The present invention was devised in view of the above-mentioned circumstances, and its object is to provide an outer peripheral side of a bearing body formed by press working on an inner peripheral side of an opening end of a cylinder body. When the seal accommodating portion for accommodating the seal whose outer periphery is in close contact is provided, the seal accommodated in the seal accommodating portion can fully exert a predetermined sealing function, for example, a shaft sealing structure portion in a hydraulic shock absorber. It is to provide a seal structure that is most suitable for use in

[0009]

In order to achieve the above-mentioned object, the structure of the present invention has a seal accommodating portion formed on the outer periphery of a bearing body that axially seals the opening end side of the cylinder body. In a seal structure that accommodates a seal that is in close contact with the inner circumference on the opening end side, the radial cross section of the seal accommodating part has the lower side as the short side, the upper side as the long side, and the outer periphery as the vertical side and the inner periphery as the outer periphery. It is assumed that the trapezoid is set to have a downward slope side toward the side, and that the radial cross section of the seal is set to substantially match the radial cross section of the seal accommodating portion.

Further, preferably, a seal is continuously provided on a lower surface of an outer peripheral end of an insert metal in an oil seal having an inner peripheral end in which a seal portion slidably contacting an outer periphery of a rod body that is inserted into and retractable from a cylinder body is continuously provided. Further, it is assumed that the cylinder body is the outer cylinder of the hydraulic shock absorber formed in the double cylinder type.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below based on the illustrated embodiments. In the illustrated embodiments, the seal structure according to the present invention is formed in a hydraulic shock absorber, particularly in a double cylinder type. It is said to be embodied in the shaft seal structure portion of the hydraulic shock absorber.

That is, in the hydraulic shock absorber, as shown in FIG. 1, a piston rod 2 as a rod body according to the present invention is inserted into a cylinder 1 so as to be retractable, and an outer peripheral side of the cylinder 1 according to the present invention. It is formed in a multi-cylinder type in which the outer cylinder 3 as a so-called cylinder body is distributed, and the opening end side of the outer cylinder 3 and the opening end of the cylinder 1 are closed by a bearing main body 10 forming a shaft sealing structure. I am trying.

In the illustrated embodiment, the bearing main body 10 can be processed without fear of breakage or the like against the pressing action from the inner and outer circumferences, and can be expected to have sufficient durability. Alternatively, it is formed by pressing a molded product from a steel pipe and has a rod body insertion hole H in the shaft core portion.
And a seal accommodating portion S for forming the seal structure according to the present invention on the outer peripheral side.

Incidentally, the bearing main body 10 is fixed to the inner periphery of the outer cylinder 3 on the opening end side, which is a predetermined position, by caulking the opening end of the outer cylinder 3, and at this time, the opening end of the outer cylinder 3 is fixed. The side and the open end of the cylinder 1 are closed together.

When the bearing main body 10 before being subjected to the above-mentioned caulking is arranged at a predetermined position, the seal accommodating portion S accommodates a predetermined seal 4 which will be described later for constituting the seal structure according to the present invention. To be done.

Explaining a little, in the bearing body 10, the rod body insertion hole H has the fixing portion 11 for fixing the opening end of the cylinder 1 to the outer periphery in the illustrated embodiment.
Holding portion 12 that is reduced in diameter and extends downward while continuing to
It is supposed that the bush 5 is formed in a cylindrical shape on the inner circumference of the holding portion 12 and makes the outer circumference of the piston rod 2 slidably contact with the inner circumference, and is held in a press-fit state.

In the illustrated embodiment, the lower end of the holding portion 12 is a collar-shaped portion 13 formed by bending the outer peripheral side, and the collar-shaped portion 13 forms the holding portion. The bush 5 can be press-fitted into the portion 12 from the so-called lower end side, and in particular, the collar-shaped portion 13 is arranged in the vicinity of a piston portion (not shown) connected to the lower end of the piston rod 2. It is said that the rebound cushion 6 can be set as a stopper portion when fully extended.

On the other hand, the seal accommodating portion S is the fixing portion 11 described above.
Is formed by an annular step portion 15 formed by bending the outer peripheral side end of the flange portion 14 extending continuously in the outer peripheral direction in the form of a horizontal flange while continuing to the upper end of the step portion 15. The predetermined seal 4, that is, the seal 4 formed in an annular shape and having an outer periphery closely contacting the inner periphery of the outer cylinder 3 is provided.

In the illustrated embodiment, the flange portion 14 communicates with an oil-leakage-recovering groove 14a extending radially from an inner peripheral end and an upper end communicating with the groove 14a through a wall thickness. A hole 14b for collecting oil leakage, and a lower end of the hole 14b opens into a reservoir chamber R formed between the cylinder and the outer cylinder 3 to bring it to the inner peripheral side of the fixing portion 11. The leaked oil for lubrication purpose is to be collected in the reservoir chamber R.

In the illustrated embodiment, the groove 14a is stopped up to the intermediate portion of the flange portion 14, and the hole 14b communicates with the end portion of the groove 14a.
Not only does the thickness of the flange portion 14 on the outer peripheral side not be reduced, and therefore the strength of the flange portion 14 is not reduced, but also the step portion 15, that is, the contact area of the seal accommodating portion S with respect to the seal 4, That is, it becomes possible not to reduce the sealing area.

Also, in the illustrated embodiment, the groove 1
4a and the hole 14b are sufficient if they are formed on the upper end surface of the flange portion 14, so that the groove 14a and the hole 14b can be accurately formed by so-called post-processing after the bearing body 10 is formed by press working. Thus, it is possible to realize the shape as set.

That is, in the case where a hole or the like of this kind is formed in a pipe material as a raw material, for example, by a drill or the like at a portion which becomes the fixing portion 11 after press working, the bearing main body 10 is formed by press working. There is a possibility that the holes will not be formed according to the setting because they may be stretched during the process.

On the other hand, in the illustrated embodiment,
Since the groove 14a and the hole 14b can be formed by so-called post-processing on the upper end surface of the flange portion 14 after the bearing main body 10 is pressed, it is possible to surely realize the shape as set.

In the present invention, the seal accommodating portion S, that is, the space formed as the seal accommodating portion S has a cross section in the radial direction in which the lower side is the short side, the upper side is the long side, and the outer periphery is vertical. It is said that the sides are set to be trapezoidal with the inner periphery being a downward slope toward the outer periphery.

As described above, the seal accommodating portion S is set to have a trapezoidal cross section in the radial direction, so that the so-called die-cutting when the seal accommodating portion S, that is, the bearing body 10 is formed by press working. Of course, when the seal accommodating portion S is formed, it is possible to easily control the accuracy of its dimensions.

In the present invention, the seal 4 accommodated in the seal accommodating portion S is accommodated in the seal accommodating portion S without any clearance, that is, the lower end portion of the seal 4 has a tightening margin in the radial direction. It is assumed that the cross section has a shape that substantially matches the radial cross section of the seal housing portion S.

As a result, in the practice of the present invention, by setting the cross-sectional area of the seal 4 to be slightly larger than the cross-sectional area of the seal accommodating portion S, when the seal 4 is accommodated in the seal accommodating portion S, The entire circumference of the seal 4 in the radial direction can be brought into close contact with the facing surface, and a necessary sealing area can be sufficiently secured to realize a perfect sealed state.

That is, the seal 4 is accommodated in the seal accommodating portion S in a press-fitted state through the oil seal 7 which will be described later due to the pressurizing action at the time of caulking the opening end of the outer cylinder 3. The outer circumference in the radial direction is pressed against the inner circumference of the outer cylinder 3, and the lower end and the inner circumference of the seal 4 in the radial direction are in close contact with the inner peripheral wall of the seal accommodating portion S. The upper end of the oil seal 7 comes into close contact with the lower surface of the oil seal 7, and the necessary seal area is secured.

By the way, the seal 4 is made of the same material as that of the seal member of this type, but in this embodiment, the oil seal 7 adjacent to the upper end of the bearing main body 10 is, for example, , It is said that they will be integrally formed by baking.

That is, the oil seal 7 is provided with an insert metal 7b having a seal portion 7a which is continuously provided on the inner peripheral end and the inner periphery of which is in sliding contact with the outer periphery of the piston rod 2. The oil seal 7 has a predetermined size. It is fixed to the upper end of the bearing main body 10 which is located at the time of caulking the opening end of the outer cylinder 3 at this time, and at this time, the insert metal 7b of the oil seal 7 is pressed against the flange portion 14 of the bearing main body 10. Will be the situation.

Therefore, by providing the seal 4 in advance on the lower surface of the outer peripheral end of the insert metal 7b, when the oil seal 7 is fixed at a predetermined position, the seal 4 is also a seal at a predetermined position. It is automatically possible to fix it in the accommodation section S.

In this case, since the seal 4 is integrated with the oil seal 7, it is possible to reduce the number of parts, and the so-called mistake in assembling the seal 4 upside down occurs. It becomes possible to prevent it.

Incidentally, when the oil seal 7 is fixed at a predetermined position, the outer peripheral end is kept in close contact with the inner periphery of the outer cylinder 3, and the oil is applied when the open end of the outer cylinder 3 is caulked. It is needless to say that the situation in which a part of the seal 4 is sandwiched between the outer peripheral end of the seal 7 and the inner periphery of the outer cylinder 3 does not occur in advance.

In the embodiment described above, the seal 4
Is integrally connected to the lower surface of the outer peripheral end of the oil seal 7, but the seal 4 may be separated from the oil seal 7 instead of this, and in this case, Although it does not contribute to the reduction of the number of points, it is advantageous in that the seal 4 and the oil seal 7 can be individually replaced.

In the above description, the seal structure according to the present invention is embodied in the shaft sealing structure portion of the double-cylinder type hydraulic shock absorber, but the seal structure is a single-cylinder type hydraulic shock absorber. Needless to say, it may be embodied in the shaft seal structure portion, and in that case, the same action and effect can be expected.

[0036]

As described above, according to the present invention, the bearing main body formed by pressing a molded product made of a steel plate or a steel pipe, which is thinner than that of a sintered steel, has an outer peripheral side. When the seal accommodating portion is formed to have a seal accommodating portion, the radial cross section of the seal accommodating portion has a lower side as a short side, an upper side as a long side, and an outer periphery as a vertical side, and an inner periphery as a downward direction toward an outer peripheral side. It is set to be a trapezoid having a slope side, and the cross section in the radial direction of the seal is set to a shape that substantially matches the cross section in the radial direction of the seal accommodating portion, so that the seal has no gap in the seal accommodating portion, That is, the entire circumference in the radial direction of the seal can be brought into close contact with the opposing surfaces to sufficiently secure the necessary sealing area and realize a perfect sealed state.

Further, in the case where the seal is continuously provided on the lower surface of the outer peripheral end of the insert metal in the oil seal having the inner peripheral end, the seal portion slidingly contacting the outer peripheral surface of the rod body inserted in the cylinder body so as to be retractable. In addition, when fixing the oil seal to the predetermined position, it is possible to automatically fix the seal in the seal accommodating portion located at the predetermined position, and the seal is integrated with the oil seal.
It is possible to reduce the number of parts, and it is possible to prevent the occurrence of so-called mistake in assembling the seal in the seal housing portion upside down.

As a result, according to the seal structure of the present invention, the seal accommodating portion for accommodating the seal whose outer periphery is in close contact with the inner periphery on the opening end side of the cylinder body is formed on the outer periphery of the bearing body formed by press working. When it is provided, the seal accommodated in the seal accommodating portion can fully exert a predetermined sealing function, and is optimal for use in, for example, a shaft sealing structure portion of a hydraulic shock absorber.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view partially showing an embodiment of a hydraulic shock absorber having a shaft sealing structure portion embodying a seal structure according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 cylinder 2 piston rod as rod body 3 outer cylinder as cylinder body 4 seal 5 bush 6 rebound cushion 7 oil seal 7a seal part 7b insert metal 10 bearing body 11 fixing part 12 forming rod body insertion hole holding part 13 tsuba Shaped portion 14 Flange portion 14a Groove for collecting oil leakage 14b Hole for collecting oil leakage 15 Step portion forming a seal accommodating portion H Rod body insertion hole R Reservoir chamber S Seal accommodating portion

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Tomoji Murakami 2-4-1 Hamamatsucho, Minato-ku, Tokyo World Trade Center Building Kayaba Industry Co., Ltd. (72) Shinichi Sugioka 2-chome, Hamamatsucho, Minato-ku, Tokyo No. 4-1 World Trade Center Building Kayaba Industry Co., Ltd.

Claims (3)

[Claims] 1. A seal structure in which a seal accommodating portion formed on the outer periphery of a bearing body that axially seals the opening end side of the cylinder body accommodates a seal whose outer periphery is in close contact with the inner periphery of the cylinder body on the opening end side, The radial cross section of the seal accommodating part is set as a trapezoid with the lower side being the short side, the upper side being the long side, the outer periphery being the vertical side, and the inner periphery being the downwardly sloping side toward the outer peripheral side. A seal structure characterized in that the cross section in the direction is set to a shape substantially corresponding to the cross section in the radial direction of the seal accommodating portion. 2. A seal is continuously provided on a lower surface of an outer peripheral end of an insert metal in an oil seal having an inner peripheral end in which a seal portion slidably contacting an outer periphery of a rod body that is inserted into and retractable from a cylinder body is inserted. Item 1 seal structure 3. The seal structure according to claim 1, wherein the cylinder body is an outer cylinder of a hydraulic shock absorber formed in a double cylinder type.