JPS6234041Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a damping force generating device for a hydraulic shock absorber, in which a piston equipped with a damping force generating device is slid in a cylinder and a coil spring is stretched around the outer periphery of the cylinder.

Conventionally, this type of hydraulic shock absorber compresses a coil spring on the outer periphery of the cylinder during the pushing stroke, and the oil in the bottom piece oil chamber between the bottom piece and the piston is pushed by the piston to open the oil passage for the bottom piece pushing stroke. It was designed so that when the check valve was pushed open, the oil flowed into the subtank's oil chamber and generated damping force during the push stroke. At this time, part of the oil passes through the oil path for the piston's push stroke, pushes open the check valve, and replenishes the oil chamber on the piston rod side.On the other hand, during the retraction stroke, the oil in the oil chamber on the piston rod side is caused by the reaction force of the coil spring. is pushed by the piston and flows into the bottom piece side oil chamber through the oil passage for the piston's retraction stroke, generating a damping force during the retraction stroke. At this time, oil is replenished from the oil chamber of the sub-tank to the bottom piece side oil chamber.
That is, during the retraction stroke, the oil in the piston rod side oil chamber in an amount equivalent to [(piston area - piston rod area) x piston movement amount] contributes to the generation of damping force during the retraction stroke. Therefore, when using the above-mentioned hydraulic shock absorber as a rear wheel suspension system for a two-wheeled vehicle, in order to absorb the large impact that the wheel receives,
It is preferable that the spring constant of the coil spring be as large as possible. On the other hand, if the spring constant of the coil spring is increased, it becomes necessary to increase the damping force during the retraction stroke caused by the reaction force. However, as mentioned above, the amount of oil that contributes to the generation of damping force during the pulling stroke is limited by [(piston area - piston rod area) x piston travel amount], so if you want to ensure sufficient piston travel amount, the oil passage Measures must be taken to reduce the area or limit the opening of the check valve. However, such means tend to have the problem that the damping force changes greatly due to slight differences in oil passage area or opening degree, making it difficult to stably manage its quality.

As a result of repeated research to solve this problem, the inventor of this invention contributed to the generation of damping force by making the stroke in which the coil spring extends due to the reaction force of the coil spring on the outer periphery of the cylinder into the pushing stroke in which the piston rod enters the cylinder. Recognizing that the amount of oil used will increase, we propose a damping force generating device related to this.

Next, an embodiment of the present invention will be described based on the accompanying drawings. Fig. 1 shows an embodiment of the installed state of the hydraulic shock absorber according to the present invention, and Fig. 2 is a cross-sectional side view of the main parts. And,
An oil hole 6 is coaxially fixed to the bottom plate 4 at an interval that forms an oil passage 3 inside the cylinder 1, and opens into an oil chamber A formed between the bottom plate 4 and the bottom piece 5. Also, an oil hole 7 is provided which opens into the piston rod side oil chamber B. 5 is a bottom piece, which is oil-tightly fitted to the end of the inner cylinder 2 with an O-ring 8 so as to form an oil chamber A between it and the bottom plate 4. Oil passage 9 provided with passage 9
A check valve 10 that operates to open only during the push stroke is provided on the oil chamber A side of the oil chamber A, and an oil passage 11 for the pull stroke is provided.
A check valve 12 is provided on the bottom piece side oil chamber C side of the oil passage 11, and is operated to open only during the retraction stroke. Reference numeral 13 denotes a piston, which is provided with an oil passage 14 for the retraction stroke, and a check valve 15 on the bottom piece side oil chamber C side of the oil passage 14, which operates so as to open only during the retraction stroke, is elasticized by a spring 16. It is mounted on the tip of the piston rod 17 so as to be able to slide freely within the inner cylinder 2. A bottom piece side oil chamber C is formed with the bottom piece 5, and a piston rod side oil chamber B is formed with a stopper lever 21, which will be described later, on the opposite side. 18 is cylinder 1
This is a closing member that closes the open end of the cylinder 1, like a normal shock absorber, through which the piston rod 17 passes, an oil seal 19 inside the cylinder 1, and a rod guide 20 that also closes the inner cylinder 2. A stopper bar 21 and the like are installed in series. 22
is a coil spring, and includes a spring receiver 23 fixed to the open end side of the cylinder 1, for example, the closing member 18 or the end of the cylinder 1, and a spring receiver 24 provided so as to be able to slide on the outer periphery of the cylinder 1. The outer periphery of the cylinder 1 is wound and stretched between them. 25 is
A spring case is provided around the outer periphery of the coil spring 22, and one end thereof is in contact with the spring receiver 24, for example.
It is fixed to the spring adjuster 26 which is slidably fitted on the outer periphery of the cylinder 1, or the spring receiver 2
4, and the other end is directly fixed to the closing member 1.
The closing member 18 is tightly secured to the piston rod 17 by a lock nut 27 on the outside of the piston rod 8 .
It is threadedly engaged with an outer peripheral screw of a disk-shaped spring adjustment plate 29 that is in contact with the rebound rubber 28 on the side. The outer periphery of the spring adjustment plate 29 is securely locked to the other end of the spring case 25 by a locking sheet 30 that is tightly secured. It is preferable that holes 31 of a suitable shape, for example, a long hole shape, be provided at suitable locations on the outer circumferential surface of the spring case so that the claws of a tool for rotating the spring case 25 can be engaged therein. Also, 3
Reference numeral 2 denotes a sub-tank that is divided into an oil chamber and an air chamber by a diaphragm 33, and is provided so that the oil chamber communicates with the oil chamber A.

The damping force generating device according to an embodiment of the present invention is
As shown in the figure, connect the cylinder 1 mounting bracket V to the vehicle body W, and connect the mounting bracket X on the piston rod 17 side.
is configured to be connected to the other end of the link mechanism Z whose one end is connected to the axle Y, so that during the pushing stroke, the oil in the oil chamber C on the bottom piece side flows into the piston 1.
3 for the pushing stroke of the bottom piece 5.
The oil flows into the oil chamber A by pushing open the check valve 10 and generates a damping force during the retraction stroke, and part of the oil flows into the oil chamber of the sub-tank 32, and part of the oil flows into the oil hole of the inner cylinder 2. 6, the oil is replenished into the piston rod side oil chamber B through the oil hole 7 via the oil passage 3. Also, during the retraction stroke, the oil in the oil chamber B on the piston rod side is pushed, and a portion passes through the oil passage 14 for the retraction stroke of the piston 13, pushes open the check valve 15, and enters the oil chamber C on the bottom piece side. A damping force is generated during the pulling stroke by the inflow and by a part of the inflow into the oil passage 3 from the oil hole 7 of the inner cylinder 2. The oil that has flowed into the oil passage 3 flows into the oil chamber A from the oil hole 6, passes through the oil passage 11 for the pulling stroke of the bottom piece 5 together with oil from the oil chamber of the sub-tank 32, and pushes open the check valve 12. Bottom piece side oil chamber C
Refilled inside. That is, during the pushing stroke in which the piston rod 17 moves into the cylinder due to the reaction force of the coil spring 18, the oil in the oil chamber C on the bottom piece side is pushed, and the oil equivalent to (piston area x piston travel distance) is pumped during the pushing stroke. This will contribute to the generation of damping force.

The coil spring 22 provided on the outer periphery of the cylinder 1 has one end fixed to the piston rod 7 side and a spring receiver 24 fixed to the other end of the spring case 25 screwed to the spring adjustment plate 29, and fixed to the closing member 18. Since it is stretched between the spring holder 23 and the
The wheel moves up and piston rod 17 moves to cylinder 1.
As the wheel is pulled out, the spring case 25 is pulled and the coil spring 22 is compressed. On the other hand, when the wheel moves downward, the piston rod 17 works as a pushing stroke, and the coil spring 22 is expanded. It is. Moreover, by rotating the spring case 25, the attachment length of the coil spring 22 can be adjusted, and the spring load can be adjusted.

As described above, in this invention, when the shock absorber that has absorbed the shock due to the contraction of the coil spring acts in the direction in which the coil spring is extended, the piston rod enters the cylinder in a pushing stroke, which contributes to the generation of damping force. It can increase the amount of oil.

This not only widens the range in which the spring constant of the coil spring can be selected, but also has the effect that the cylinder shape can be made smaller if the spring constant of the coil spring is the same as the conventional one.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the installed state of a hydraulic shock absorber according to the present invention, and FIG. 2 is a cross-sectional side view of a main part showing an embodiment of the device according to the present invention. 1... Cylinder, 2... Inner cylinder, 3... Oil path, 4... Bottom plate, 5... Bottom piece, 6, 7... Oil hole, 8... O-
Ring, 9... Oil path for push stroke, 10... Check valve for push stroke, 11... Oil path for pull stroke, 12... Check valve for pull stroke, 13... Piston, 14... Oil path, 15... Check valve , 16... Spring, 17... Piston rod, 18...
Closing member, 19... Oil seal, 20... Rod guide, 21... Stopper lever, 22... Coil spring, 23... (Fixed) spring holder, 24... (Slidable) spring holder, 25... Spring case, 26... Spring adjuster. , 27... Lock nut, 28... Rebound rubber, 29... Spring adjustment plate, 30... Lock seat, 31... Hole, 32... Sub-tank, A... Oil chamber [between bottom plate 4 and bottom piece 5], B... Piston rod side Oil chamber, C...Bottom piece side oil chamber, V,
X...Mounting bracket.

Claims (1)

[Scope of utility model registration request] A piston rod having a piston at the tip that slides inside the cylinder protrudes from one end of the cylinder,
A hydraulic shock absorber is used, with the stroke in which the coil spring provided on the outer periphery of the cylinder extends as the pushing stroke of the piston rod, and the stroke in which the coil spring contracts as the retracting stroke of the piston rod. A bottom piece 5 fixedly attached to an inner cylinder, which is coaxially provided with an oil hole 6 opening into the oil chamber A and an oil hole 7 opening into the piston rod side oil chamber B.
In addition to providing an oil passage 9 and a check valve 10 for the pushing stroke and an oil passage 11 and a check valve 12 for the pulling stroke,
A damping force generating device for a hydraulic shock absorber in which a piston 13 that freely slides in an inner cylinder 2 is provided with a check valve 15 that opens only during the retraction stroke and an oil passage 14.