JPH11294509A - Hydraulic buffer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce weight by aluminizing an outer cylinder while ensuring the strength in a cylinder side by making the cylinder of iron and steel material, absorb an elongation difference in an axial direction between the outer cylinder and the cylinder generated by a difference of thermal expansion coefficient between the outer cylinder made of aluminum and the cylinder made of iron and steel to prevent a generation of a looseness in the axial direction in a connection part of the cylinder, and improve a sealing performance in the connection part of the cylinder. SOLUTION: An annular groove 5d is formed in an inner peripheral part of an annular step 5c opposite to an end face of an upper end opening of a cylinder 2, a plate spring 8 is held so as to be interposed between the annular step 5c of a rod guide member 5 and the end face of the upper end opening of the cylinder 2, and an inner peripheral side of the plate spring 8 is press fitted by predetermined load in an axial direction inside the annular groove 5d to be compressed and deformed, whereby the plate spring 8 is assembled in a state that the plate spring 8 is compressed and deformed so as to be a disc spring shape.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic shock absorber, and more particularly, to a technique for solving the problems associated with reducing the weight of an outer cylinder.

[0002]

2. Description of the Related Art In recent years, there has been a demand for reducing the fuel consumption by reducing the weight of a vehicle, thereby saving energy. Therefore,
Conventionally, in a hydraulic shock absorber, the cylinder is a member that directly receives the lateral force of the piston, sliding friction, the pressure of the hydraulic oil, etc., so it is necessary to form it with a steel material in terms of strength, but it is much stronger than the cylinder It has been proposed to reduce the weight by making the outer cylinder that does not require aluminum into aluminum. However, since there is a difference in the thermal expansion coefficient between the aluminum outer cylinder and the steel cylinder, when the temperature becomes high due to the operation of the hydraulic shock absorber, the axial expansion difference between the outer cylinder and the cylinder is equal to the upper and lower connecting portions of the cylinder. There is a problem that axial play is generated. Techniques that can be used to solve such problems include, for example, Shokai 61
Japanese Patent Application Laid-Open No. -82143 discloses an example. This conventional example is not based on the difference in thermal expansion coefficient between the outer cylinder and the cylinder, but as shown in FIG.
A substantially U-shaped cross section is formed between the locking step of the end wall member 102 on the 01 side and the upper opening end of the cylinder 103, and between the lower opening end of the cylinder 103 and the locking step of the base member 104. And has a structure in which annular compression spring members 105 and 106 are interposed. That is, by utilizing the structure of the conventional example as described above, the axial expansion difference based on the thermal expansion coefficient difference between the outer cylinder and the cylinder can be reduced.
Since it is absorbed by the axial elastic deformation of No. 06, it can be said that it is possible to prevent the generation of the axial play.

[0003]

However, the compression spring members 105 and 106 in the conventional example described above are
Since the opening end surface of the cylinder 103 is supported on the outer peripheral surface side of the opening end portion having a substantially U-shaped cross section, the compression spring member 105 is deformed in the axial direction as shown in the explanatory diagram of the main part of FIG. In the assembling step of applying the set load, in the state (a) set by the set load from the state before the setting (b), a part of the repulsive force due to the compression of the compression spring member 105 is changed by the cylinder 103 as shown by the arrow. Acting on the cylinder 103 as a component force in the direction of expanding the opening edge of the cylinder outward, the inner diameter of the opening of the cylinder 103 increases, and a gap is generated between the cylinder 103 and the press-fit connection portion to the end wall member 102, As a result, there is a problem that the performance of the damping force characteristic due to the leakage of the hydraulic oil is deteriorated, and the press-fitting connection portion is loosened, which causes a reduction in durability. In order to solve this problem, it is conceivable to interpose a sealing material such as an O-ring, but the number of parts increases and the cost increases.

The present invention has been made in view of the above-mentioned conventional problems. The cylinder side can be reduced in weight by making the outer cylinder aluminum while securing the strength with a steel material. Absorbs the difference in axial expansion between the outer cylinder and the cylinder, which is caused by the difference in thermal expansion coefficient between the aluminum outer cylinder and the steel cylinder, to prevent the occurrence of axial play in the upper and lower connecting portions of the cylinder, and It is an object of the present invention to provide a shock absorber that can improve the sealing property of the connecting portion.

[0005]

According to a first aspect of the present invention, there is provided a hydraulic shock absorber in which an outer cylinder having one end closed and a reservoir chamber formed in the outer cylinder. A piston which is slidably provided by defining the inside of the cylinder into two upper and lower chambers, and a piston rod having one end fixed to the piston and the other end protruding outside the cylinder. A rod-side closing member that closes a gap between the piston rod and one end opening of the cylinder and an opening of the outer cylinder and guides sliding of the piston rod; and a base member that closes the other end opening of the cylinder. And, between the rod-side closing member and the cylinder opening end face and / or between the base member and the cylinder opening end face,
The cylinder is provided with an elastic member for applying an axial force and a component force for pressing the opening edge in the axial direction. In the hydraulic shock absorber according to a second aspect, in the hydraulic shock absorber according to the first aspect, a recess is formed in a locking step portion that is axially opposed to a cylinder opening end surface of the rod-side closing member and / or the base member. The elastic member is interposed in a compressed state in which the inner peripheral side of the elastic member is pressed against the opening end face of the cylinder and the outer peripheral side is pressed against the outer peripheral locking step of the recess. According to a third aspect of the present invention, in the hydraulic pressure absorber according to the first aspect, the elastic member is formed in a disc spring shape, and an inner peripheral side of the disc spring elastic member has the rod-side closing member and / or Alternatively, a means is provided in which the outer peripheral side is in pressure contact with the outer peripheral side of the opening end surface of the cylinder in a compressed state, while being pressed against the locking step portion of the base member which faces the cylinder opening end surface in the axial direction.

[0006]

In the hydraulic shock absorber according to the first aspect of the present invention, as described above, the cylinder is disposed in the axial direction between the rod-side closing member and the cylinder opening end face and / or between the base member and the cylinder opening end face. An elastic member that applies a force and a component force that presses the opening edge in the axial direction is interposed.The thermal expansion coefficient of the outer cylinder and the cylinder is determined by the axial force and the axial elastic deformation of the elastic member. The axial extension difference based on the difference is absorbed, thereby preventing the occurrence of the axial play of the cylinder. Therefore, it is possible to reduce the weight of the hydraulic shock absorber by forming the outer cylinder side with aluminum while securing the strength by forming the cylinder side with a steel material as in the related art. In addition, the diameter of the opening edge of the cylinder is reduced by the axial force component by the elastic member, thereby improving the sealing performance at the connecting portion of the cylinder. In the hydraulic shock absorber according to claim 2, as described above, the elastic member has its inner peripheral side pressed against the opening end face of the cylinder, while its outer peripheral side has the rod-side closing member and / or
Alternatively, the base member is interposed in a compressed state in which it is pressed against an outer peripheral side locking step portion of a concave portion formed in a locking step portion facing the cylinder opening end face in the axial direction, and in this state, the elastic member Since only the inner peripheral side is pressed into the concave portion by the compression and is deformed into a disk spring shape, the cylinder is subjected to the axial force and the component force for pressing the opening edge in the axial direction. Further, the axial set load applied to the cylinder by the repulsive force due to the compression of the elastic member can be easily set to an arbitrary value by the step between the locking step and the concave portion and the axial plate pressure of the elastic member. it can. Claim 3
In the above-described hydraulic shock absorber, the elastic member is formed in the shape of a disc spring, and the inner peripheral side of the disc spring-like elastic member is axially opposed to the cylinder opening end surface of the rod-side closing member and / or the base member. While being pressed against the stop, the outer peripheral side is interposed in a compressed state in which the outer peripheral side is pressed against the outer peripheral side of the opening end face of the cylinder. In this state, the axial force and the opening edge are applied to the cylinder in the axial center. And a component force pressing in the direction acts.

[0007]

Embodiments of the present invention will be described below in detail with reference to the drawings. (First Embodiment of the Invention) First, the structure of the hydraulic shock absorber of the first embodiment of the invention shown in FIGS. 1 and 2 will be described. FIG.
1 is a partially cutaway front view showing a hydraulic shock absorber according to Embodiment 1 of the present invention, and FIG. 2 is an enlarged sectional view of the essential part.

That is, as shown in FIG. 1, the hydraulic shock absorber according to the first embodiment of the present invention is provided with an outer cylinder 1 having a closed lower end and a reservoir chamber C formed in the outer cylinder 1. And a piston 3 which is slidably defined by defining an upper chamber A and a lower chamber B inside the cylinder 2, and a lower end fixed to the piston 3 and the other end being outside the cylinder 2. A protruding piston rod 4 and a rod guide member (rod side) for closing the gap between the piston rod 4 and the upper end opening of the cylinder 2 and the upper end opening of the outer cylinder 1 and guiding the sliding of the piston rod 4. Side closing member) 5, a rod seal member 6 for hydraulically sealing between the outer cylinder 1 and the piston rod 4, a base member 7 for closing a lower end opening of the cylinder 2, and an upper end opening of the cylinder 2. Between the end face and the rod guide member 5 Interposed a plate spring (elastic member) 8
And a lower spring seat 9.

More specifically, the rod guide member 5 has a small-diameter portion 5a press-fitted into the upper end opening of the cylinder 2.
A bush 1 for guiding the sliding of the piston rod 4 is formed on the inner peripheral surface of the small-diameter portion 5b, and has a large-diameter portion 5b press-fitted into the upper end opening of the outer cylinder 1.
0 is attached, and the small-diameter portion 5a and the large-diameter portion 5b
An annular groove (recess) 5d is formed in an inner peripheral edge side of an annular step portion (locking step portion) 5c formed between the cylinder 2 and a portion facing the upper end opening end surface of the cylinder 2 in the axial direction. I have. 5 d of this annular groove is formed so that the diameter of the outer peripheral edge is larger than the outer diameter of the cylinder 2.

The leaf spring 8 is formed in the shape of a flat circular plate from spring steel.
Between the annular stepped portion 5c and the end face of the upper end opening of the cylinder 2. That is, by applying a predetermined axial load between the base member 7 and the rod guide member 5, the inner peripheral side of the leaf spring 8 is pressed into the annular groove 5d as shown in the enlarged portion of FIG. In this state, the upper end caulking portion 1a of the outer cylinder 1 is connected to the rod seal member 6 as shown in FIG.
By bending and fixing to the outer periphery of the upper end of
As shown in the enlarged portion of FIG. 2, the leaf spring 8 is assembled in a state of being compressed and deformed into a disc spring shape. The cylinder 2 is made of a steel material, while the outer cylinder 1 is made of aluminum.

In FIG. 2, reference numeral 11 denotes a sealing member for hydraulically sealing between the outer cylinder 1 and the rod guide member 5, and in FIG. 1, reference numeral 12 denotes a knuckle.

Next, the operation and effect of the first embodiment of the invention will be described. In the hydraulic shock absorber according to the first embodiment of the present invention, as described above, the cylinder 2 side is formed of steel as usual, while ensuring the strength, while the outer cylinder 1 side is formed of aluminum. It is possible to reduce the weight of the hydraulic shock absorber. Also, as mentioned above,
Since there is a difference in the thermal expansion coefficient between the aluminum outer cylinder 1 and the steel cylinder 2, when the temperature becomes high due to the operation of the hydraulic shock absorber, the upper and lower cylinders 2 are moved by the difference in the axial extension between the outer cylinder 1 and the cylinder 2. Although axial play is generated at the connecting portion, in the first embodiment of the present invention, as described above, the upper end opening end face of the cylinder 2 and the rod guide member 5 are connected.
Since the leaf spring 8 is assembled in a state of being compressed and deformed into a disc spring shape by a predetermined axial load between the annular spring 5 and the annular step portion 5c, a change in the amount of axial elastic deformation due to the repulsive force of the leaf spring 8 As a result, the axial expansion difference based on the thermal expansion coefficient difference between the outer cylinder 1 and the cylinder 2 is absorbed, and therefore, it is possible to prevent the occurrence of axial play due to a temperature change.

Further, as shown in the enlarged portion of FIG. 2, the leaf spring 8 is pushed into the annular groove 5d only by the predetermined axial load and is deformed into a disc spring shape. In addition to the axial force, the cylinder 2 is subjected to a component force that presses the opening edge in the axial center S direction as shown by an arrow, and the diameter of the upper end opening edge of the cylinder 2 is reduced by this component force. Since the pressure input to the small diameter portion 5a is strengthened, the sealing performance can be improved.

Therefore, the cylinder 2 side is made of aluminum to make the outer cylinder 1 lightweight while securing the strength by the steel material, and the thermal expansion coefficient difference between the aluminum outer cylinder 1 and the steel cylinder 2 makes it possible. It is possible to absorb the generated axial expansion difference between the outer cylinder 1 and the cylinder 2 to prevent generation of axial play at the upper and lower connecting portions of the cylinder 2 and to improve the sealing performance of the connecting portion of the cylinder 2. Is obtained.

The axial set load applied to the cylinder 2 by the repulsive force based on the compression deformation of the leaf spring 8 is:
Since an arbitrary value can be easily set by the step between the annular step portion 5c and the annular groove 5d and / or the plate pressure of the leaf spring, a stable axial set load can be obtained. Is obtained.

(Embodiment 2) Next, an embodiment 2 of the invention will be described. In the description of the second embodiment of the present invention, the same components as those in the first embodiment of the present invention are denoted by the same reference numerals, and the description thereof will be omitted. Only the differences will be described.

The hydraulic shock absorber according to the second embodiment of the present invention
As shown in an enlarged sectional view of the main part in FIG. 3, a leaf spring 21 forming an elastic member is formed of a spring steel into a disk spring shape which is inclined downward from the inner periphery to the outer periphery, and has an inner peripheral edge. The part side is the annular step part 5 of the rod guide member 5.
c, and the rod guide member 5 is pressed in a state where the radially intermediate portion is pressed against the outer peripheral edge of the upper end opening edge of the cylinder 2.
And is interposed between the annular stepped portion 5c and the upper end opening end surface of the cylinder 2 while being compressed by a predetermined set load.

Therefore, also in the hydraulic shock absorber according to the second embodiment of the present invention, in addition to the axial force, a component force for pressing the opening edge in the axial direction as shown by the arrow acts on the cylinder 2. In this state, substantially the same operations and effects as those of the first embodiment of the present invention can be obtained, and
Since it is not necessary to form an annular groove in the annular step portion 5c,
The cost can be reduced.

Although the embodiments of the present invention have been described in detail with reference to the drawings, the specific configuration is not limited to the embodiments of the present invention, and design changes and the like may be made without departing from the gist of the present invention. The present invention is also included in the present invention.

For example, in the embodiment of the present invention, the outer cylinder is made of aluminum and the cylinder is made of a steel material. However, the outer cylinder may be made of other materials.

In the embodiment of the present invention, the leaf spring is interposed between the upper end opening of the cylinder and the rod guide member. However, the leaf spring is interposed between the lower end opening of the cylinder and the base member. It may be.

[0022]

As described above, in the hydraulic shock absorber according to the first aspect of the present invention, the cylinder is provided between the rod-side closing member and the cylinder opening end face and / or between the base member and the cylinder opening end face. The cylinder side is made of iron and steel material while securing the strength of the outer cylinder aluminum by using an elastic member that acts to apply an axial force and a component force that presses the opening edge in the axial direction. In addition to the axial expansion difference between the outer cylinder and the cylinder, which is caused by the difference in thermal expansion coefficient between the aluminum outer cylinder and the steel cylinder, It is possible to obtain the effect that the occurrence of backlash can be prevented and the sealing performance of the connecting portion of the cylinder can be improved without increasing the number of parts. Claim 2
In the hydraulic shock absorber according to claim 1, in the hydraulic shock absorber according to claim 1, a concave portion is formed in a locking step portion axially opposed to a cylinder opening end surface of the rod-side closing member and / or the base member, Since the elastic member is interposed in a compressed state in which the inner peripheral side of the elastic member is pressed against the opening end surface of the cylinder and the outer peripheral side is pressed against the outer peripheral side locking step portion of the concave portion, the elastic member is compressed and deformed. The axial set load applied to the cylinder by the repulsive force based on the pressure can be easily set to an arbitrary value by the step between the locking step and the concave portion and / or the axial plate pressure of the elastic member. Thus, the effect that the set load in the axial direction can be obtained can be obtained. According to a third aspect of the present invention, in the hydraulic pressure absorber according to the first aspect, the elastic member is formed in a disc spring shape, and an inner peripheral side of the disc spring elastic member has the rod-side closing member and / or Alternatively, a means is provided in which the outer peripheral side is pressed against the outer peripheral side of the opening end surface of the cylinder in a compressed state while being pressed against the locking step portion axially opposed to the cylinder opening end surface of the base member. The effect of the first aspect can be obtained without forming a concave portion in the step portion.

[Brief description of the drawings]

FIG. 1 is a partially cutaway front view showing a hydraulic shock absorber according to Embodiment 1 of the present invention.

FIG. 2 is an enlarged sectional view of a main part of the hydraulic shock absorber according to the first embodiment of the present invention.

FIG. 3 is an essential part enlarged sectional view showing a hydraulic shock absorber according to Embodiment 2 of the present invention.

FIG. 4 is a partially cutaway front view showing a conventional hydraulic shock absorber.

FIG. 5 is an explanatory diagram of a main part expansion operation of a conventional hydraulic shock absorber.

[Explanation of symbols]

 Reference Signs List A upper chamber B lower chamber C reservoir chamber 1 outer cylinder 2 cylinder 3 piston 4 piston rod 5 rod guide member (rod-side closing member) 5c annular step (locking step) 5d annular groove (recess) 7 base member 8 plate Spring (elastic member) 21 Leaf spring (elastic member)

Claims (3)

[Claims] 1. An outer cylinder having one end closed, a cylinder formed with a reservoir chamber formed in the outer cylinder, and a piston slidably provided by defining the interior of the cylinder into two upper and lower chambers. A piston rod having one end fixed to the piston and the other end protruding outside the cylinder; and closing the piston rod and one end opening of the cylinder and the opening of the outer cylinder while sliding the piston rod. A rod-side closing member that guides movement, and a base member that closes the other end opening of the cylinder, wherein a portion between the rod-side closing member and the cylinder opening end surface and / or between the base member and the cylinder opening end surface. A hydraulic shock absorber characterized in that an elastic member is provided between the cylinder for applying an axial force and a component force for pressing the opening edge in the axial direction. 2. A concave portion is formed in a locking step portion of the rod-side closing member and / or the base member, which is axially opposed to the cylinder opening end surface, and the inner peripheral side of the elastic member is pressed against the opening end surface of the cylinder. 2. The hydraulic shock absorber according to claim 1, wherein an elastic member is interposed in a compressed state in which an outer peripheral side is pressed against an outer peripheral side locking step portion of the concave portion. 3. A locking step in which the elastic member is formed in the shape of a disc spring, and the inner peripheral side of the disc spring-like elastic member is axially opposed to the end surface of the cylinder opening of the rod-side closing member and / or the base member. 2. The hydraulic shock absorber according to claim 1, wherein the hydraulic shock absorber is interposed in a compressed state in which the outer peripheral side is pressed against the outer peripheral side of the opening end surface of the cylinder while being pressed against the cylinder.