JPS6228337B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic shock absorber mainly used as a rear suspension in a two-wheeled motor vehicle. Conventionally, in this type of shock absorber, a piston at the lower end of a piston rod extending from a top metal is fitted into a cylinder whose inside is a hydraulic oil chamber, and a spring is applied between the outer periphery of the outer cylinder and the top metal. Although such a type is known, in this case, it is preferable that the shock absorber act to correct changes in the height of the vehicle body due to changes in the load of occupants, etc. The purpose of the present invention is to obtain a device that satisfies such requirements, and a piston at the lower end of a piston rod extending from an upper metal is fitted into a cylinder having a hydraulic oil chamber inside the outer cylinder. In a type in which a spring acts between the outer periphery of the cylinder and the upper metal, a pressure chamber whose volume can be varied in the vertical direction is formed between the upper metal and the spring receiver on the upper side of the spring, and the pressure is applied to the piston rod. The rod is formed into a hollow rod with an internal axial hollow hole communicating with the chamber, and an internal axial oil chamber at the bottom of the cylinder, and an oil hole opening the oil chamber laterally. A plunger pump is constructed by fixing an adjusting rod having an adjustment rod and fitting the rod into the hollow rod described above.

An example of implementing the present invention will be explained with reference to the attached drawings.

In the drawings, reference numeral 1 denotes an outer cylinder, in which a cylinder 3 having a hydraulic oil chamber 2 inside is fixed, an oil reservoir chamber 4 is formed around its outer periphery, and a bottom valve 5 is provided at its bottom.

In the drawing, reference numeral 6 indicates a piston rod extending downward from the upper metal 6, and the piston 8 at the lower end of the rod 7 is fitted into the cylinder 3. A spring 9 is provided between the spring 9 and the spring 6. 1 in drawings
0 indicates a lower spring receiver of the spring 9, and 11 indicates an upper spring receiver.

The bottom valve 5 and the piston 8 are each provided with a damping force generating mechanism consisting of small-diameter through holes 5a, 8a, and the like.

Although the above is not particularly different from the conventional one, according to the present invention, the upper spring receiver 11 is attached to the upper spring receiver 6.
A pressure chamber 12 having a variable volume in the vertical direction is provided between the piston rod 7 and the pressure chamber 12.
An internal axial hollow hole 13 leading into the rod 7 is provided to form the rod 7 into a hollow rod. More specifically, a downward step on the outer periphery is formed in the atsupa metal 6, and the spring receiver 11 having an upward step on the upper surface is fitted thereto to form the pressure chamber 12 between the two steps. This was made to communicate with the upper end of the hollow hole 13 described above via a communication path 12a extending inside the metal 6. Furthermore, an internal axial oil chamber 14 is provided at the bottom of the cylinder 3.
An adjusting rod 16 having an oil hole 15 opening laterally into the chamber 14 is fixedly installed, and the rod 1
6 was fitted into the hollow hole 13 of the hollow rod 7 described above, so that both rods 16 and 7 constituted a plunger pump.

That is, according to the mutual sliding of both rods 16 and 7,
The volume inside the hollow hole 13 is increased or decreased to form the oil hole 15.
The inflow and outflow of oil can be provided through the inflow and outflow of oil. Furthermore, an orifice 1 is provided in the communication path 12a.
7, and a relief valve 18 is provided in the adjustment rod 16, which opens when the oil pressure in the oil chamber 14 increases.

To explain its operation, as the Atsupa metal 6 moves up and down, the piston 8 moves up and down in the cylinder 3, and at this time, oil is guided through the through holes 5a and 8a to generate a damping force, and the spring 9 The present invention cooperates with this, and is not particularly different from the conventional system in this respect, but according to the present invention, the following operation occurs. That is, when the load acting on the vehicle body is a specified value and the height of the vehicle body is a specified height, the piston rod 7 is located at a position where its tip substantially coincides with the oil hole 15 as shown in the figure. Considering the case where the rod 7 moves up and down from this state, the plunger pump consisting of both rods 16 and 7 only repeats the inflow and outflow of oil through the oil hole 15, and thus the pressure inside the pressure chamber 12 increases. The volume is always kept approximately constant. Next, considering the case where the vehicle body height decreases due to an increase in the load described above, the piston rod 7 moves downward beyond the oil hole 15 and moves up and down around the lower position. In this way, in the plunger pump, the oil hole 15 repeatedly opens near the upper limit position of the stroke of the piston rod 7. In other words, oil repeatedly flows in through the oil hole 15, and this oil flows into the hollow hole. It is gradually guided into the pressure chamber 12 from the inside of the hole 13 via the communication path 12a, and the volume inside the pressure chamber 12 gradually increases, and thus the Atsupa metal 6 moves upward and the vehicle body height is gradually corrected to the increasing side. be done. Next, if we consider the case where the height of the vehicle increases significantly, the piston rod 7 will be located above the oil hole 15 and will move up and down around this position, and the plunger pump will flow out oil through the oil hole 15. By repeating this, the volume inside the pressure chamber 12 is gradually reduced, the top metal 6 moves downward, and the vehicle body height is corrected to the decreasing side.

According to the present invention, the upper metal 6 which is attached to the upper end of the piston rod 7 and receives the spring 9 has a pressure chamber 12 whose volume can be varied in the vertical direction between it and the spring receiver 11 of the spring 9. There is a spring receiver 11 that supports one end of the spring 9.
The displacement of the piston rod 7 can be automatically corrected according to the axial sliding movement of the shock absorber, and the piston rod 7 is provided with an internal axial hollow hole 13 that extends into the pressure chamber 12. 7 is formed into a hollow rod, and an adjusting rod 16 having an axially internal oil chamber 14 and an oil hole 15 opening the oil chamber 14 to the side is fixed at the bottom of the cylinder 1. Since the rod 16 is fitted with the piston rod 7 and both rods 7 and 16 constitute a plunger pump, it functions not only as a shock absorber but also as a means for correcting the height of the vehicle body. This has the advantage that it can be advantageously used, for example, as a lift fork for a two-wheeled motor vehicle.

[Brief explanation of the drawing]

The drawing is a cutaway side view of one example of the device of the present invention. 1... Outer cylinder, 3... Cylinder, 2... Hydraulic oil chamber, 6... Upper metal, 7... Piston rod, 8... Piston, 9... Spring, 11... Spring receiver, 12... Pressure chamber, 13...Hollow hole, 14...
Oil chamber, 15...oil hole, 16...adjustment rod.

Claims (1)

[Scope of Claims] 1. A piston at the lower end of a piston rod extending from a top metal is fitted into a cylinder whose hydraulic oil chamber is inside the outer cylinder, and a spring is applied between the outer periphery of the outer cylinder and the top metal. In the hydraulic shock absorber, a pressure chamber having a variable volume in the vertical direction is formed between the upper metal and a spring receiver on the upper side of the spring, and the piston rod is provided with an internal hollow hole in the axial direction that extends into the pressure chamber, The rod is formed into a hollow rod, and an adjusting rod having an internal oil chamber in the axial direction and an oil hole opening the oil chamber laterally is fixed to the bottom of the cylinder, and the rod is fixed to the bottom of the cylinder. A hydraulic shock absorber is constructed by fitting together a hollow rod and a plunger pump. 2. The hydraulic shock absorber according to claim 1, which includes an orifice in the communication path between the pressure chamber and the hollow hole. 3. The hydraulic shock absorber according to claim 1, wherein the adjustment rod is provided with a relief valve that opens when the oil pressure in the oil chamber increases.