JPH056428Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a bottom piece fixing structure for a shock absorber used in vehicles, etc.

(Prior art) Conventionally, hydraulic shock absorbers used in vehicles, etc.
For example, a bottom piece is fixed to the inner peripheral surface of the lower end of the cylinder by caulking, and a reservoir chamber is provided on the outside of the cylinder, and an oil hole communicating with this reservoir chamber is formed, so that when the piston rod enters the cylinder, Hydraulic oil corresponding to the volume of the rod entering the cylinder flows into the reservoir chamber, and hydraulic oil corresponding to the volume of the rod leaving when the piston rod leaves the cylinder is returned from the reservoir chamber to the cylinder, so that the rod is in a locked state. There are known devices designed to prevent this from happening.

(Problem to be solved by the invention) In the hydraulic shock absorber as described above, when fixing the bottom piece to the inner peripheral surface of the lower end of the cylinder by caulking, it is necessary to prevent the bottom piece from clogging the oil hole of the cylinder. Since positioning is required, caulking is troublesome, and a dedicated groove for caulking is required on the outer peripheral surface of the bottom piece.

(Means for Solving the Problems) In order to solve the above problems, the present invention forms an annular groove communicating with the oil hole of the cylinder on the outer peripheral surface of the bottom piece, and the bottom piece is swaged into the annular groove. It was fixed to the cylinder at the section.

(Function) When caulking and fixing the bottom piece to the cylinder, the oil hole of the cylinder can be positioned by aligning the bottom piece with the annular groove, making the caulking process easier, and the annular groove of the bottom piece Since it also serves as a groove for receiving the part, there is no need to form a separate dedicated caulking groove.

(Example) An example of the present invention will be described below based on the accompanying drawings.

Figure 1 is a sectional view of a hydraulic shock absorber implementing the bottom piece fixing structure according to the present invention, Figures 2 and 3 are
The figures are enlarged sectional views of main parts of the same shock absorber at different positions on the outer periphery of the bottom piece.

A hollow rod 2 is inserted into the cylinder 1 from above, and a piston 3 that slides on the inner peripheral surface of the cylinder 1 is attached to the tip of the hollow rod 2. A side oil passage 6 is formed, a compression side valve 7 that opens and closes the compression side oil passage 5 is installed on the upper surface of the piston 3, and an extension side valve 8 that opens and closes the expansion side oil passage 6 is installed on the lower surface of the piston 3. are doing.

Further, a cylinder cap 10 is fitted onto the inner peripheral surface of the upper end of the cylinder 1.
A rod guide 11 that slides on the outer circumferential surface of the hollow rod 2 is fitted on the upper side of the rod guide 11, and oil seals 12 and 13 that slide on the outer circumferential surface of the hollow rod 2 are fitted on the upper and lower sides of the rod guide 11. A plate 14 is fitted below the oil seal 13, and a stopper lever 15 is fitted below the plate 14.

A bypass oil passage 16 that bypasses the piston 3 is formed in the upper end of the hollow rod 2, and a valve seat 17 is fitted into the opening of the bypass oil passage 16 at the upper end of the hollow rod 2. The push rod 18 is inserted through the valve seat 18 so that it can move forward and backward, so that the tip of the push rod 18 faces the opening of the valve seat 17.

Further, an upper bracket 21 for attaching to the vehicle body is attached to the upper end of the hollow rod 2, a stop lever 22 is attached to the lower surface of the upper bracket 21, and an upper spring is attached to the outer periphery of the upper bracket 21. A sheet 23 is fitted. An adjuster rod 25 is screwed into the upper bracket 21 so as to be movable back and forth in a direction perpendicular to the axial direction.A taper portion 26 is formed on the adjuster rod 25, and the upper end of the push rod 18 is abutted to this taper portion. I'm letting you touch me. Furthermore, a stopper 27 is fitted in the upper bracket 21 on the front side of the adjuster rod 25 to restrict the maximum amount of advance of the adjuster rod 25.

A lower bracket 30 for attaching to a wheel is attached to the lower end of the cylinder 1, and a lower bracket 30 is attached to the lower end of the cylinder 1.
A case 31 is fitted onto the outer circumferential surface of the cylinder 1 and locked with a stopper ring 32. A partition wall 33 made of an elastic body is installed inside this case 31 to define a reservoir chamber SR. forms an oil hole 34 that communicates with the inside of the partition wall 33 of this reservoir chamber SR.

On the inner peripheral surface of the lower end of this cylinder 1,
The bottom piece 36 is fixed. As shown in FIG. 2, an annular groove 37 is formed on the outer peripheral surface of the bottom piece 36, which communicates with the oil hole 34 of the cylinder 1, and this annular groove 37 communicates with the bottom oil chamber SB through the oil hole 38. As shown in FIG.
9 is inserted into the annular groove 37 of the bottom piece 36 to fix the bottom piece 36 to the inner peripheral surface of the cylinder 1.

Further, an oil passage 41 is formed in the bottom piece 36, and a valve 42 for opening and closing this oil passage 41 is provided.
A valve stopper 43 for regulating the movement range of the valve 42 is attached to the center of the bottom piece 36, and an oil hole 44 is formed in the center of the valve stopper 43 in the axial direction. And cylinder 1
A first slider 46 for pressing the outer periphery of the valve 42 is slidably fitted inside the bottom piece 36, and an oil hole 47 is formed in the first slider 46. A second slider 48 that presses the extension side valve 8 of the piston 3 is slidably fitted in the second slider 48 , and an oil hole 49 is formed in the second slider 48 . A spring 50 is interposed between the first slider 46 and the bottom piece 36.
The second slider 48 is pressed toward the piston 3 side.

Further, a cylindrical body 51 is fitted on the outer circumferential surface of the case 31, an underspring seat 52 is fitted on the outer circumferential surface of the cylindrical body 51, and a cam surface 53 is formed on the lower surface of the underspring seat 52. A stopper 54 that comes into contact with the cam surface 53 is fixed to the outer peripheral surface of the cylinder 51, and a recess 55 is formed at the lower end of the cylinder 51, and the case 3 is inserted into the recess 55.
Head 5 of bolt 56 fixing 1 and cylinder 1
6a and further fit the sub-seat 58 on the outer peripheral surface of the upper end of the cylinder 1, so that between the upper spring seat 23 and the sub-seat 58 and between the sub-seat 58 and the under spring seat 52, Suspension springs 60 and 61 are provided respectively.

The operation of the hydraulic shock absorber configured as above will be explained below.

First, when assembling, cylinder 1
When fixing the bottom piece 36 to the inner circumferential surface of the cylinder 1, the annular groove 37 of the bottom piece 36 is aligned with the oil hole 34 of the cylinder 1, and tightening is performed from the outer circumferential surface of the cylinder 1 with a punch. The portion 39 enters into the annular groove 37 of the bottom piece 36 and the bottom piece 36 is fixed to the cylinder 1.

At this time, the bottom piece 36 can be positioned by aligning the annular groove 37 of the bottom piece 36 with the oil hole 34 of the cylinder 1.

Next, during operation, as the hollow rod 2 moves downward together with the piston 3 during the compression stroke, the hydraulic oil in the lower oil chamber S2 flows from the oil hole 49 of the second slider 48 into the piston 3. Side oilway 5
The compression side valve 7 is opened to flow into the upper oil chamber S1 to generate a damping force.

At this time, as the hollow rod 2 enters into the cylinder 1, the hydraulic oil in the cylinder oil chamber S1 reaches the inner peripheral side of the valve 42 of the bottom piece 36 by a volume corresponding to the volume of entry into the hollow rod 2. 1 to open by bending against the pressing force of the slider 46, and flow into the bottom oil chamber SB through the oil passage 41 of the bottom piece 36, and then the oil hole 38 of the bottom piece 36, the annular groove 37, and the cylinder 1. The oil flows into the reservoir chamber SR through the oil hole 34 while expanding the partition wall 33 outward, and a damping force is generated by the oil passage 41 and the valve 42.

In this case, when the stroke position of the piston 3 is large, the amount of compression of the spring 50 increases and the reaction force becomes strong, so the pressing force with which the first slider 46 presses the outer circumference of the valve 42 increases,
As the pressure required to open the valve 42 increases, the damping force generated in the oil passage 41 and the valve 42 increases, and when the stroke position of the piston 3 is small, the amount of compression of the spring 50 decreases, causing a reaction force. becomes weak, so the first slider 4
6 becomes smaller, the pressure required to open the valve 42 becomes smaller, and the damping force generated in the oil passage 41 and the valve 42 becomes smaller. Therefore, the damping force on the compression side can be changed depending on the stroke position of the piston 3.

Also, in the extension stroke, the hollow rod 2 moves to the piston 3.
, the hydraulic oil in the upper oil chamber S1 passes through the extension side oil passage 6 of the piston, opens the extension side valve 8, and enters the oil hole 4 of the second slider 48.
9 into the lower oil chamber S2 to generate damping force.

At this time, as the hollow rod 2 withdraws from the cylinder 1, the partition wall 33 contracts due to the internal pressure of the reservoir chamber SR by a volume corresponding to the volume of the withdrawal of the hollow rod 2, and the partition wall 33 of the reservoir chamber SR contracts.
The inner hydraulic oil returns from the oil hole 34 of the cylinder 1 to the bottom oil chamber SB through the annular groove 37 of the bottom piece 36 and the oil hole 38, and then from this bottom oil chamber SB to the oil hole 41 of the bottom piece 36 to the outer periphery of the valve 442. The side is bent against the pressing force of the first slider 46 and flows into the lower oil chamber S2 through the oil hole 47.

In this extension stroke, when the stroke position of the piston 3 is large, the amount of compression of the spring 50 increases and the reaction force becomes strong, so the second slider 4
8 presses the outer circumference of the extension-side valve 8 of the piston 3, and the pressure required to open the extension-side valve 8 increases, causing pressure in the extension-side oil passage 6 and the extension-side valve 8 of the piston. When the generated damping force increases and the stroke talk position of the piston 3 is small, the amount of compression of the spring 50 decreases and the reaction force becomes weak, so the second slider 48 moves the outer circumference of the valve 8 on the extension side of the piston 3. The pressing force becomes smaller, the pressure required to open the extension valve 8 becomes lower, and the damping force generated in the extension oil passage 6 of the piston 3 and the extension valve 8 becomes smaller. Therefore, the damping force on the compression side and the expansion side can be changed depending on the stroke talk position of the piston 3.

(Effects of the invention) As explained above, according to the invention, an annular groove communicating with the oil hole of the cylinder is formed on the outer circumferential surface of the bottom piece. When fixing the bottom piece to the cylinder by crimping, it is possible to position the cylinder by aligning the oil hole with the annular groove of the bottom piece, making the crimping process easier.
Furthermore, since the bottom piece annular groove also serves as a groove for receiving the caulking portion, there is no need to separately form a dedicated caulking groove.

[Brief explanation of the drawing]

Figure 1 is a sectional view of a hydraulic shock absorber implementing the bottom piece fixing structure according to the present invention, Figures 2 and 3 are
The figures are enlarged sectional views of main parts of the same shock absorber at different positions on the outer periphery of the bottom piece. In addition, in the drawing, 1 is a cylinder, 2 is a hollow rod,
3 is a piston, 31 is a case, 33 is a partition wall, 34
36 is the oil hole of the cylinder, 36 is the bottom piece, 37 is the annular groove, 39 is the caulking part, and SR is the reservoir chamber.

Claims (1)

[Scope of utility model claims] In the shock absorber, a bottom piece is fixed to the inner circumferential surface of the lower end of the cylinder, and a reservoir chamber is provided on the outer side of the lower end of the cylinder, and an oil hole communicating with the reservoir chamber is formed. A bottom piece fixing structure for a shock absorber, characterized in that an annular groove communicating with an oil hole of the cylinder is formed in the cylinder, and the bottom piece is fixed to the cylinder by a caulking part that enters the annular groove.