JP2002061697A - Bottom structure of hydraulic shock absorber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reinforce a bottom part of a damper tube, make common use capable to a car of different kind though weight is lightened of the damper tube, and ensure even concentric assembly workability of a cylinder relating to the damper tube, in a hydraulic shock absorber provided with an I-joint in a side of a bottom part outer surface of the damper tube. SOLUTION: In this bottom structure of hydraulic shock absorber 10, a reinforcing cap 50 is interposed between an inner surface of a bottom part 11A of a damper tube 11 and a bottom piece 43.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a bottom structure of a hydraulic shock absorber.

[0002]

2. Description of the Related Art Conventionally, as a hydraulic shock absorber, a cylinder is built in a damper tube, and a bottom piece that partitions an oil chamber inside the cylinder and a reservoir chamber between the damper tube and the cylinder is arranged at a lower end of the cylinder. In some cases, an eye joint is provided on the outer surface of the bottom of the damper tube.

[0003]

According to the prior art, when the above-described damper tube provided with an eye joint is applied to a vehicle having a different vehicle weight, the cylindrical portion of the damper tube has no problem in strength, but the bottom portion has strength. Insufficient and cannot be shared.

Therefore, in the case where the bottom of the damper tube is formed by spinning, it is necessary to provide the bottom with a strength corresponding to the vehicle weight, and the tube cannot be shared.
When trying to share the tubes, the thickest tubes having the highest strength are shared, which impairs the weight reduction of the tubes.

Further, in the case where the bottom of the damper tube is closed by the cap, it is necessary to provide the bottom with a strength corresponding to the vehicle weight, so that the tube and the cap cannot be shared. When trying to share a tube and a cap,
The thickest tube and cap, which are the strongest, are used in common, which reduces the weight of the tube.

In a double-cylinder type hydraulic shock absorber in which a cylinder is built in a damper tube, as described in Japanese Utility Model Laid-Open Publication No. 4-77039, the cylinder is concentric with the damper tube between the damper tube and the bottom piece. A centering plate for mounting is provided.

An object of the present invention is to provide a hydraulic shock absorber having an eye joint on the bottom outer surface of a damper tube.
The purpose of the present invention is to reinforce the bottom of the damper tube so that the damper tube can be used for different models while reducing the weight, and that the cylinder can be coaxially assembled to the damper tube.

[0008]

According to the first aspect of the present invention, a cylinder is built in a damper tube, and a bottom piece that partitions an oil chamber inside the cylinder and a reservoir chamber between the damper tube and the cylinder is provided at a lower end of the cylinder. In the bottom structure of a hydraulic shock absorber provided with an eye joint on the side of the bottom outer surface of the damper tube, a reinforcing cap is interposed between the bottom inner surface of the damper tube and the bottom piece.

According to a second aspect of the present invention, a damper tube has a built-in cylinder, and a bottom piece for partitioning an oil chamber inside the cylinder and a reservoir chamber between the damper tube and the cylinder is disposed at a lower end of the cylinder. In the bottom structure of the hydraulic shock absorber provided with an eye joint on the outer surface of the bottom of the tube, the bottom piece is seated on the inner surface of the bottom of the damper tube in a range from a central portion corresponding to a fixed portion of the eye joint to a peripheral portion. It is provided with a surface.

According to a third aspect of the present invention, a cylinder is built in a damper tube, and a bottom piece that partitions an oil chamber inside the cylinder and a reservoir chamber between the damper tube and the cylinder is disposed at a lower end of the cylinder. In the bottom structure of a hydraulic shock absorber provided with an eye joint on the bottom outer surface side of the tube, a reinforcing cover is attached around the bottom outer surface of the damper tube, and the reinforcing cover is provided with an eye joint.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the bottom portion of the damper tube is formed by spinning.

[0012]

According to the first aspect of the present invention, the following operations are provided. Since the bottom portion of the damper tube is reinforced by the addition of the reinforcing cap, it is possible to avoid insufficient strength of the bottom portion even when applied to a vehicle having a high vehicle weight. Since the cylinder portion and the bottom portion of the damper tube are not thickened, the damper tube can be used for various types of vehicles from low vehicle weight to high vehicle while reducing the weight.

[0013] With the bottom piece held by the reinforcing cap, the reinforcing cap is seated on the inner surface of the bottom portion of the damper tube over a peripheral portion (close to the cylindrical portion), and the bottom piece is disposed at the lower end portion of the cylinder. Therefore, the concentric assembly of the damper tube and the cylinder can be improved without using the conventional centering plate.

According to the second aspect of the invention, the following operations are provided. The bottom piece sits over a wide area from the center to the periphery of the bottom inner surface of the damper tube. Therefore, since the bottom of the damper tube is reinforced by reducing the vehicle weight per unit area acting on the bottom of the damper tube, insufficient strength of the bottom can be avoided even in application to a vehicle having a high vehicle weight. Since the cylinder portion and the bottom portion of the damper tube are not thickened, the weight of the damper tube can be reduced, and the damper tube can be commonly used for various types of low to high vehicle weight vehicles.

With the bottom piece disposed at the lower end of the cylinder, the bottom piece is seated on the inner surface of the bottom of the damper tube in a range extending to the peripheral portion (close to the cylindrical portion), so that the conventional centering plate is not used. Concentric assembly of the damper tube and the cylinder can be improved.

According to the third aspect of the invention, the following effects are obtained. Since the bottom portion of the damper tube is reinforced by attaching a reinforcing cover provided with an eye joint around the outer surface of the bottom portion of the damper tube, insufficient strength of the bottom portion can be avoided even when applied to a vehicle having a high vehicle weight. Since the cylindrical portion and the bottom portion of the damper tube are not thickened, the damper tube can be used for various models of low to high vehicle weight while reducing the weight.

According to the fourth aspect of the invention, the following operations are provided. By forming the bottom of the damper tube by spinning, the thickness of the tube can be reduced and the weight can be reduced.

[0018]

FIG. 1 is an overall half sectional view showing a hydraulic shock absorber according to a first embodiment, FIG. 2 is an enlarged sectional view showing a lower portion of FIG. 1, and FIG. 3 is a sectional view showing an assembly of a bottom piece and a reinforcing cap. FIGS. 4 and 5 are schematic views showing the reinforcing cap, FIG. 5 is an enlarged lower sectional view of the hydraulic shock absorber of the second embodiment, and FIG. 6 is an enlarged lower sectional view of the hydraulic shock absorber of the third embodiment.

(First Embodiment) (FIGS. 1 to 4) FIG. 1 shows a double-cylinder type hydraulic shock absorber 10, which constitutes a double pipe in which a cylinder 12 is built in a damper tube 11, and a piston is provided in the cylinder 12. The rod 13 is inserted, a mounting bracket (not shown) fixed to the upper end of the piston rod 13 is connected to the vehicle body side, and the eye joint 14 welded to the outer surface of the bottom 11A of the damper tube 11 is connected to the wheel side. Of the suspension device.

The hydraulic shock absorber 10 includes a lower spring seat 15 on the outer periphery of the damper tube 11 and a piston rod 13.
A suspension spring 16 is interposed between upper spring seats (not shown) supported by a mounting bracket at the upper end of the suspension spring 16.

The hydraulic shock absorber 10 includes a rod guide 17 for a piston rod 13 inserted into a cylinder 12, a bush 18, and an oil seal 19.
Of the cylinder 12 and the upper end of the cylinder 12.

The hydraulic shock absorber 10 is provided with a damper tube 1.
A valve stopper 21 is provided on the outer surface of the upper end of the piston rod 1, and a bump rubber (not shown) of the piston rod 13 is brought into contact with the bump stopper 21 to regulate the maximum compression stroke. The piston rod 13 is provided with a rebound seat 22 and a rebound rubber 23 at an insertion portion into the cylinder 12, and abuts the rebound rubber 23 against the rod guide 17 to regulate the maximum extension stroke.

The hydraulic shock absorber 10 includes the piston valve device 3
0 and the bottom valve device 40, and the damping force generated by them controls the expansion and contraction vibration of the piston rod 13 accompanying the absorption of the impact force by the suspension spring 16.

(Piston Valve Apparatus 30) The piston valve apparatus 30 includes a valve stopper 3
1. A check valve 32, a piston 33, a disc valve 34, and a valve stopper 35 are mounted, and these are fixed with a nut 36.

At the time of compression, the piston side oil chamber 37
The oil A flows through the pressure side flow path 38A of the piston 33 and flexes and deforms the check valve 32 to open the rod side oil chamber 37.
It is led to B. In addition, at the time of extension, the rod-side oil chamber 37B
The oil passes through the expansion-side flow path 38B (not shown) of the piston 33 and flexes and opens the disk valve 34, is guided to the piston-side oil chamber 37A, and generates an expansion-side damping force.

(Bottom valve device 40) Hydraulic shock absorber 10
As shown in FIG. 2, the damper tube 11 and the cylinder 1
The gap 2 is a reservoir chamber 41, and the interior of the reservoir chamber 41 is partitioned into an oil chamber and a gas chamber. Then, the bottom valve device 40 closes the bottom 11A of the damper tube 11 by spinning, and arranges a bottom piece 43 that partitions the piston-side oil chamber 37A inside the cylinder 12 from the reservoir chamber 41 at the lower end of the cylinder 12. Reinforcement cap 5 for connecting piston-side oil chamber 37A and reservoir chamber 41 to be described later.
The communication is made possible by the flow path 53 provided at the zero point. A bolt 44 and a nut 45 are fastened to the bottom piece 43, and a disc valve 46, the bottom piece 43, a check valve 47, and a valve stopper 48 are interposed between the bolt 44 and the nut 45.

At the time of compression, oil corresponding to the volume of the piston rod 13 that enters the cylinder 12 passes through the flow path 49A of the bottom piece 43 from the piston-side oil chamber 37A to bend and open the disk valve 46. Channel 53
It is extruded into the reservoir chamber 41 via the pressure chamber, and obtains a compression-side damping force.
At the time of extension, oil corresponding to the retreat volume of the piston rod 13 retreating from the cylinder 12 pushes and opens the check valve 47, and is supplied from the reservoir chamber 41 to the piston side oil chamber 37A via the flow path 53 and the flow path 49B of the bottom piece 43. Is done.

However, in this embodiment, in order to reinforce the bottom 11A of the damper tube 11 where the eye joint 14 is provided, the reinforcing cap 50 is interposed between the concave inner surface of the bottom 11A and the bottom piece 43. Reinforcement cap 50
As shown in FIGS. 3 and 4, is a concave inner surface of the bottom 11A of the damper tube 11 and a fixing portion 1 of the eye joint 14.
A seating surface 51 is provided on the lower surface, which seats along the entire range from the central portion to the peripheral portion corresponding to 4A, and also has a centering function for the damper tube 11. Further, the reinforcing cap 50 includes a plurality of rising holding portions 52 for fitting the outer peripheral leg portions 43A of the bottom piece 43 in a press-fit state at a plurality of circumferential positions on the upper outer edge, and connects the piston side oil chamber 37A and the reservoir chamber 41. A flow channel 53 is formed between adjacent rising holding portions 52 on the upper surface.

The hydraulic shock absorber 10 is assembled by the bottom piece 4
3 is press-fitted into the reinforcing cap 50 and connected to form a sub-assembly in which the small-diameter outer peripheral portion of the bottom piece 43 is press-fitted into the lower end of the cylinder 12, and this sub-assembly is inserted into the damper tube 11, Seating surface 5 of reinforcing cap 50
1 is seated on the inner surface of the bottom 11A of the damper tube 11. And the piston rod 1 having the piston 33
3 is inserted into the cylinder 12, the lower end small diameter portion of the rod guide 17 is inserted into the upper end of the cylinder 12, and the caulking portion 20 of the damper tube 11 is used to seal the cylinder 12 and the bottom piece via the oil seal 19 and the rod guide 17. 43,
The reinforcing cap 50 is swaged and fixed.

Therefore, according to the present embodiment, the following operations are provided. The bottom 11A of the damper tube 11 is
Can be avoided even when applied to a vehicle having a high vehicle weight. Since the cylinder portion 11B and the bottom portion 11A of the damper tube 11 are not thickened, the weight of the damper tube 11 is reduced while reducing the vehicle weight.
It can be shared by various types of high-rise vehicles.

With the bottom piece 43 held by the reinforcing cap 50, the reinforcing cap 50 is
1. The bottom piece 43 is seated on the inner surface of the bottom 11A over a peripheral portion (close to the cylinder 11B), and the bottom piece 43 is
Since the damper tube 11 and the cylinder 12 can be coaxially assembled without using a conventional centering plate. By providing the seating surface 51 of the reinforcing cap 50 so as to follow the entire concave inner surface of the bottom 11A of the damper tube 11, the concentric assembly of the damper tube 11 and the cylinder 12 can be further improved.

By forming the bottom 11A of the damper tube 11 by spinning, the thickness of the tube can be reduced and the weight can be reduced.

Second Embodiment (FIG. 5) The second embodiment of FIG. 5 is different from the first embodiment of FIG. 2 in that a bottom valve device 6 instead of the bottom valve device 40 is provided.
0 has been adopted.

The bottom valve device 60 is constructed by attaching a bottom piece 61 to the lower end of the cylinder 12, and a reservoir 67 is provided between the bottom piece 61 and the bottom 11 A of the damper tube 11 by a flow path 67 described later. The chamber 41 communicates with the piston side oil chamber 37A. In addition, the bottom piece 61
A cage-shaped spring receiving member 62 is provided. A spring 63, a valve seat 64, and a disc valve 65 are interposed between the bottom piece 61 and the spring receiving member 62. 65 is the bottom piece 61
Is in pressure contact with the protruding valve seat on the outer periphery.

At the time of compression, the oil corresponding to the volume of the piston rod 13 that enters the cylinder 12 passes through the flow path 64A of the valve seat 64 to deflect and deform the disk valve 65 to open. The piece 61 is extruded into the reservoir chamber 41 via the flow path 61A and the flow path 67 to obtain a pressure-side damping force. At the time of extension, the oil corresponding to the retreat volume of the piston rod 13 retreating from the cylinder 12 pushes and opens the valve seat 64 and the check valve 65 against the spring 63, and the fluid flows from the reservoir chamber 41 to the flow path 67 and the bottom piece 61. Piston side oil chamber 37A via 61A
Will be replenished.

Further, in the present embodiment, the damper tube 1
In order to reinforce the bottom 11A provided with the first eye joint 14, the bottom piece 61 is made large and the damper tube 1
The bottom piece 61 is provided with a seating surface 66 which is seated along substantially the entire concave inner surface of the bottom 11A. That is, the seating surface 66 of the bottom piece 61 is provided on the inner surface of the bottom 11A of the damper tube 11 in a range from the center corresponding to the fixing portion 14A of the eye joint 14 to the periphery.
In addition, the bottom piece 61 has a part of the seating surface 66 cut out,
A flow path 67 connects the piston-side oil chamber 37A and the reservoir chamber 41.

Therefore, according to the present embodiment, the following operations are provided. The bottom piece 61 is the bottom 11A of the damper tube 11.
Sit on a wide area from the center to the periphery of the inner surface. Accordingly, by reducing the vehicle weight per unit area acting on the bottom 11A of the damper tube 11, the damper tube 1
Since the bottom portion 11A is reinforced, insufficient strength of the bottom portion 11A can be avoided even when applied to a vehicle having a high vehicle weight. Since the cylinder portion 11B and the bottom portion 11A of the damper tube 11 are not thickened, the weight of the damper tube 11 is reduced while reducing the vehicle weight.
It can be shared by various types of heavy vehicles.

In a state where the bottom piece 61 is arranged at the lower end of the cylinder 12, the bottom piece 61 is seated on the inner surface of the bottom 11A of the damper tube 11 in a range extending to the peripheral portion (close to the cylindrical portion 11B). Damper tube 11 and cylinder 1 without centering plate
2 concentric assembling property can be improved. The seating surface 66 of the bottom piece 61 also has a shape in which the seating surface 66 is seated following the entire concave inner surface of the bottom 11A of the damper tube 11.
Concentric assembly of the damper tube 11 and the cylinder 12 can be further improved.

Third Embodiment (FIG. 6) The third embodiment of FIG. 6 differs from the first embodiment of FIG. 2 in that a reinforcing cover 70 is attached around the outer surface of the bottom 11A of the damper tube 11. That is, the eye joint 14 is welded to the outer surface of the reinforcing cover 70. Reinforcement cover 70
Is a bottom 70A that is attached around the outer surface of the bottom 11A of the damper tube 11 and to which the eye joint 14 is welded.
And a cylindrical portion 70B that is press-fitted or inserted into the cylindrical portion 11B of the damper tube 11 and welded.

The bottom piece 43 of the bottom valve device 40 is disposed between the bottom 11A of the damper tube 11 and the lower end of the cylinder 12. The bottom piece 43 includes a flow path 43B in a leg 43A sandwiched between the damper tube 11 and the cylinder 12.

Therefore, according to the present embodiment, the following operations are provided. Since the bottom 11A of the damper tube 11 is reinforced by attaching the reinforcing cover 70 provided with the eye joint 14 around the outer surface of the bottom 11A of the damper tube 11, the bottom 11A can be applied to a vehicle having a high vehicle weight. Insufficient strength can be avoided. Since the cylindrical portion 11B and the bottom portion 11A of the damper tube are not thickened, the damper tube 11 can be used for various types of low to high vehicle weight while reducing the weight.

The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration of the present invention is not limited to this embodiment, and the design may be changed without departing from the scope of the present invention. The present invention is also included in the present invention. For example, the present invention is not limited to the one in which the eye joint is fixed to the bottom of the damper tube formed by spinning, but the one in which the cap to which the eye joint is welded is formed by welding or the like to the opening end of the damper tube. Can also be applied.

[0043]

As described above, according to the present invention, in a hydraulic shock absorber in which an eye joint is provided on the outer surface of the bottom portion of the damper tube, the bottom portion of the damper tube is reinforced to reduce the weight of the damper tube while allowing a different vehicle type. Can be shared,
Concentric assembling of the cylinder to the damper tube can also be ensured.

[Brief description of the drawings]

FIG. 1 is an overall half sectional view showing a hydraulic shock absorber according to a first embodiment.

FIG. 2 is a lower enlarged sectional view of FIG. 1;

FIG. 3 is a sectional view showing an assembly of a bottom piece and a reinforcing cap.

FIG. 4 is a schematic view showing a reinforcing cap.

FIG. 5 is a lower enlarged sectional view of a hydraulic shock absorber according to a second embodiment.

FIG. 6 is a lower enlarged sectional view of a hydraulic shock absorber according to a third embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Hydraulic shock absorber 11 Damper tube 11A Bottom part 12 Cylinder 14 Eye joint 37A Piston side oil chamber 41 Reservoir chamber 43 Bottom piece 50 Reinforcement cap 61 Bottom piece 66 Seating surface 70 Reinforcement cover

Claims (4)

[Claims] 1. A cylinder having a built-in cylinder in a damper tube, a bottom piece for partitioning an oil chamber inside the cylinder and a reservoir chamber between the damper tube and the cylinder is arranged at a lower end of the cylinder, and a bottom part of the bottom outer surface of the damper tube is provided. A bottom structure of a hydraulic shock absorber having an eye joint on a side thereof, wherein a reinforcing cap is interposed between an inner surface of a bottom portion of a damper tube and a bottom piece. 2. A cylinder having a built-in cylinder in a damper tube, and a bottom piece for partitioning an oil chamber inside the cylinder and a reservoir chamber between the damper tube and the cylinder is disposed at a lower end of the cylinder. In the bottom structure of the hydraulic shock absorber provided with the eye joint on the side, the bottom piece is provided with a seating surface that is seated on a bottom inner surface of the damper tube in a range from a central portion corresponding to a fixed portion of the eye joint to a peripheral portion. A bottom structure of a hydraulic shock absorber, characterized in that: 3. A cylinder having a built-in cylinder in a damper tube, and a bottom piece for partitioning an oil chamber inside the cylinder and a reservoir chamber between the damper tube and the cylinder is disposed at a lower end of the cylinder. A bottom structure of a hydraulic shock absorber provided with an eye joint on a side thereof, wherein a reinforcing cover is attached to a periphery of a bottom outer surface of a damper tube, and an eye joint is provided on the reinforcing cover. 4. The bottom structure of the hydraulic shock absorber according to claim 1, wherein a bottom portion of the damper tube is formed by spinning.