JPS6141766B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic shock absorber for suspending the rear wheels of two-wheeled vehicles, etc., and in particular to a hydraulic shock absorber for adjusting the height of a vehicle, which automatically adjusts the height of the vehicle while the vehicle is running in response to changes in load. This relates to shock absorbers.

Conventionally, in hydraulic shock absorbers that suspend the rear wheels of two-wheeled vehicles, methods such as cam-type spring load adjustment or adjustment of the air pressure have been used to deal with load fluctuations due to the number of passengers or loaded cargo. Both systems are equipped with manual equipment such as tools and air compressors for adjustment.

Therefore, the adjustment is troublesome and is difficult to use in reality. The present invention solves these problems by automatically adjusting the vehicle height while driving in response to load fluctuations, and also automatically varying the damping force characteristics in accordance with the load.
It provides a rear suspension with good maneuverability and ride comfort. An embodiment of the present invention will be described in detail below with reference to the drawings.

Figure 1 shows one example of the automobile height adjustable hydraulic shock absorber of the present invention.
It is a schematic diagram showing a partial cross section showing an example. As shown in the figure, a cylindrical cylinder 2 is provided inside the damper case 1 to form an oil reservoir chamber A, into which a bottom piece 3 is press-fitted, and the bottom piece 3 is in contact with the bottom of the damper case 1. . A disk valve 4 is pressed against the bottom piece 3 by a valve spring 5. As shown in FIG. 2, the disc valve 4 has a plurality of notches 4a on its inner diameter, and an orifice 4b is provided between the outer diameter and the notches 4a. A blow valve mechanism is provided in the bottom piece 3 so as to face the notch 4a and the orifice 4b so as to be concentric with the circumference of the flow passage, and the inner flow passage has a blow valve mechanism composed of a slide valve 5a and a spring 5b. . Note that this blow valve mechanism opens when the internal pressure of the oil chamber B exceeds a design value. Also, bottom piece 3
A flow path leading to the oil chamber A is provided between the damper case 1 and the cylinder 2, so that oil can flow from the oil chamber B in the cylinder 2. A partially hollow inner rod 6 stands upright from the bottom piece 3, and a position detection orifice 7 penetrates through the inner rod 6.

A rod guide 8 is press-fitted into the other end of the cylinder 2, and a hollow piston rod 9 is slidably fitted into the inner diameter of the rod guide 8. A step is formed on the outer periphery of the piston rod 9, and a valve seat 10 is provided on the step.
2 is pressed against the piston 13, the piston 13 and the cylinder 2 are slidably fitted, and the piston ring 1
4 defines the inside of the cylinder into oil chambers B and C. As shown in FIG. 3, the valve 12 has a plurality of oil holes 12a arranged concentrically on the outside, and a plurality of oil holes 12b arranged concentrically on the inside. There is also a flow path concentrically within the piston 13 facing the holes 12a and 12b, and a slide valve 15 is connected to a coil spring 16 in the inner flow path.
It is closed due to A valve housing 17 is fitted with the tip of the rod 9 with a screw, and fixes the piston 13 therein. An O-ring 18 is provided on the outer periphery of the housing 17, a spring receiver 19 is slidably attached to the housing 17 via the O-ring 18, and an O-ring 20 is provided on the inner diameter of the spring receiver 19 to seal between the housing 17 and the housing 17. Note that the spring receiver 19 and the coil spring 16 are in contact with each other, and the housing 1
7 is provided with a flow path 21 connecting the inside and outside, and a check valve 23 is pressed against a valve seat 24 on the inside diameter thereof by a valve spring 22.

The valve seat 24 has a plurality of concentric channels 25, and an elastic sealing member 26 and a sliding member 27 are press-fitted into the inner diameter of the valve seat 24.
Both are slidably fitted into the inner rod 6. Further, the valve seat 24 is caulked to the valve housing 17 via an O-ring 28. The piston rod 9 is sealed with oil by an oil seal 29 and extends to the outside of the damper case 1, and the damper case 1 is caulked and fixed onto the oil seal 29 via an end plate 30. The other end of the piston rod 9 is screwed to a joint metal 31, and a plunger case 32 is similarly screwed to the screw, and the joint metal 31 and the plunger case 32 are fixed as a double nut mechanism.

The part of the plunger case 32 that contacts the upper metal 31 has radial grooves 3 as shown in
2a is formed, and there is a flow path 33 in the piston rod 9 at a position facing the groove 32a.
Connected to the hollow part. Also plunger case 3
2 and the piston rod 9 is sealed with oil by an O-ring 34. Further, an annular plunger 35 is slidably fitted to the outer periphery of the plunger case 32, and O-rings 3 are attached to the inner and outer diameters of the plunger 35.
6 and 37 are attached, and the outer diameter of the plunger 35 is slidably fitted to the upper case 38. The upper case 38 is sandwiched between the upper meter 31 and the plunger case 32, and a plurality of notches 38a are formed in the inner diameter part of the upper case 38 as shown in FIG. The plunger 3
An oil flow path reaching one end of 5 is configured. Therefore, a high pressure chamber D is defined by the plunger case 32, upper case 38, and plunger 35. A spring 40 is in contact with the lower end of the plunger 35 via a dust seal 30, and the other end of the spring 40 is connected to a concave groove of the damper case 1 via a stop ring 41, and the spring seat 4
It has been accepted by 2. Further, the inside of the plunger case 32 opposite to the joint metal 31 has a notch for tightening a double nut, and a groove for fixing a stopper ring 43 is provided on the outer periphery of the end thereof. It has the function of regulating strokes. Further, a groove is provided in the end surface of the flange portion of the joint metal 31 to maintain airtightness by an O-ring 44.

Next, its operation will be described.

When the load is light (when the center of the amplitude of the piston 13 is above the position detection orifice 7), the inside of the cylinder 2 is grooved with working oil, and when the shock absorber is in the compression stroke, the oil chamber C at the top of the piston Zoom in, push open the valve 12, and refill oil from the oil chamber B at the bottom. The oil corresponding to the volume of the piston rod 9 entering the cylinder 2 flows into the oil chamber A via the orifice 4b of the disc valve 4 which is in pressure contact with the bottom piece 3, and the remaining oil flows into the oil chamber A through the flow path 2 of the valve seat 24. The liquid then opens the check valve 23, which is pressed by a weak valve spring 22, and flows out into the hollow part of the piston rod 9. The hollow part of the piston rod 9 is the flow path 3.
3 and communicates with the high pressure chamber D formed by the plunger case 32, upper case 38, and plunger 35, so the high pressure oil in the oil chamber B flows through the plunger 3.
5 and actuates to compress the spring 40. However, when the piston enters the extension stroke, the oil chamber B at the bottom of the piston expands, so the oil compressed in the cylinder 2 flows back from the hollow part of the piston rod 6, through the hollow part of the inner rod 6, and from the position detection orifice 7, causing the plunger to 35 returns to the initial state. Then, the disc valve 4 on the bottom piece opens to replenish the insufficient oil. Note that the damping force generation mechanism during expansion, which is generated through the oil hole of the valve 12 of the piston, is the same as the conventional one.

When the load is heavy (when the center of the amplitude of the piston 13 is below the position detection orifice 7) In this case, the compression stroke is the same as above, but
In the extension stroke, the state in which the position detection orifice is closed by the valve seat 24 takes longer than the state in which the orifice 7 is open.

Therefore, if the amount of oil flowing into the high pressure chamber D during the compression stroke is set to be greater than the amount flowing out from the position detection orifice 7 during the extension stroke, the volume of the high pressure chamber D will expand with each vibration. .

By repeating the above-mentioned operation, the plunger 3
5 moves downward to contract the spring 40, and conversely, the plunger 3 of the spring 40
The reaction force applied to the joint metal 31 and the piston rod 9 increases, pushing the joint metal 31 and the piston rod 9 upward.

Therefore, the vehicle height that has gradually lowered will be automatically adjusted back to its original position due to vibrations during driving.

FIG. 6 shows its operating characteristics. As shown by curve a in the figure, from the state P' where the upper surface of the plunger 35 is in contact with the upper case 38, the stop ring 4
Even if the load applied to the shock absorber increases, the spring 40
This shows the range in which the vehicle height can be kept constant by contracting the spring and increasing the spring reaction force. P
-P″ curve shows the case where the load increases further.
Note that the practical range of a constant vehicle height is, for example, the case of one or two passengers plus a shock absorber.

However, due to this operation, the vehicle height is kept constant by the position detection orifice 7, but it is stabilized by a strong spring reaction force for a large live load (point C in Figure 6), and a weak spring reaction force is used for a small live load. Since it is stabilized by reaction force (point A in Figure 6), if the damping force that dampens the movement of the shock absorber is constant, overdamping or insufficient damping will occur. Therefore, appropriate damping is required for the reaction force of the spring. In contrast, in the present invention, the spring seat 19 is applied to the spring seat 19 by a pressure balanced with the reaction force of the spring 40 by a flow path that passes from the hollow part of the piston rod 9 through the flow path 21 of the valve housing 17 and communicates with the spring receiver 19. Coil spring 16 in contact
It has the function of pressurizing the shock absorber and changes the damping force when the shock absorber is compressed. This allows the damping force characteristics of the compression stroke to be automatically varied according to the load. The damping force characteristics are shown in FIG. However, the A, B, C, D, and E curves are A, B, and E in Figure 6.
It is a damping force characteristic curve with respect to the spring load position at C, D, and E.

As described above, according to the present invention, the vehicle height can be fully automatically adjusted in response to load fluctuations, and the damping force characteristics can also be automatically varied according to the reaction force of the spring, resulting in stable maneuverability and ride comfort. .

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing a partially sectional view of an embodiment of the automotive height adjustable hydraulic shock absorber of the present invention, Fig. 2 is a plan view of the disc valve, Fig. 3 is a plan view of the valve, and Fig. 4 is a perspective view of the plunger case, FIG. 5 is a perspective view of the upper case, FIG. 6 is a diagram showing the vehicle height-spring load characteristic curve of the shock absorber of the present invention, and FIG. 7 is a damping force characteristic curve during compression. FIG. 1... Damper case, 2... Cylinder, 3...
...Bottom piece, 4...Disc valve, 5a...
...Slide valve, 6...Ninener rod, 7
...Position detection orifice, 9...Piston rod, 12...Valve, 13...Piston, 15...
...Check valve, 16...Coil spring,
17... Valve housing, 19... Spring holder, 2
1...Flow path, 22...Valve spring, 23...
...Check valve, 24...Valve seat, 25
...Flow path, 31...Joint metal, 32...
Plunger case, 33...flow path, 35...plunger, 38...upper case, 40...coil spring, 43...stopper ring.

Claims (1)

[Claims] 1 Piston 13 with a damping force generator at the tip
The piston rod 9 to which the piston rod is fixed is slidably inserted into the cylinder 2 filled with oil, and the other end of the piston rod 9 is extended to the outside of the cylinder and connected to the upper joint metal 31, and the cylinder side and the joint metal are connected. In a hydraulic shock absorber for a motorcycle or the like in which a coil spring 40 is stretched between the sides, an inner rod 6, which is hollow inside and closed at one end and has a position detection orifice 7 formed in the middle, is placed concentrically with the cylinder 2 at the bottom of the cylinder 2. The open free end of the inner rod is inserted into the piston rod 9 which is hollow inside, and the outer periphery of the tip of the hollow piston rod 9 is opened when compressed and closed when extended to prevent oil from flowing inside the piston rod. A valve housing 17 is fitted with a check valve 23 for controlling the flow, and on the outer periphery of the housing there is a slide valve 15 for the piston 13 that opens when it is extended, and a spring bearing 19.
A cylindrical plunger case 32 and an upper case 38 are fitted concentrically to the outer periphery of the upper part of the hollow piston rod. , an annular plunger 35 is slidably disposed between the inner and outer circumferential walls of both cases, the two cases and the plunger constitute a high pressure chamber that communicates with the oil chamber in the hollow piston rod, and the plunger 35 is stretched around the outer periphery of the cylinder. An automobile height adjustable hydraulic shock absorber characterized in that one end of a coil spring 40 is locked.