JPS6248103B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic shock absorber that is installed laterally and can obtain a high damping force during a push stroke, and more specifically, a hydraulic shock absorber that is installed between a vehicle body and a link in a swing arm type rear suspension. It is related to vessels.

A piston rod with oil sealed in the cylinder and a piston at the tip that slides inside the cylinder is extended from one end of the cylinder, and between a spring holder fixed to the cylinder and a spring holder fixed to the piston rod side,
Conventionally, in a hydraulic shock absorber with a coil spring wound around the outer circumference of the cylinder, the piston and bottom piece are provided with check valves and oil passages that operate separately depending on the push stroke and pull stroke, respectively, to prevent the piston from sliding. During the push stroke, the piston pushes the oil in the bottom piece side oil chamber between the bottom piece and the piston, passes through the bottom piece's oil passage for the push stroke, and pushes open the check valve that opens only during the push stroke, creating a damping force. It generates and leaks into the oil chamber of the external sub-tank.
It is a so-called double tube type, and the inside of the cylinder is divided into a high pressure gas chamber and an oil chamber by a free piston.
A single tube type piston was known in which the piston was provided with an orifice having a check valve that opened only during the push stroke or the pull stroke. In a double tube type hydraulic shock absorber, part of the oil is replenished into the oil chamber on the piston rod side between the piston and the closed part at the open end of the cylinder through the oil passage for the piston's pushing stroke, and during the pulling stroke. The oil in the oil chamber on the piston rod side is pushed by the piston, passes through the oil path for the piston's retraction stroke, pushes open the check valve that opens only during the retraction stroke, generates a damping force, and flows into the oil chamber on the bottom piece side. At this time, oil is replenished from the oil chamber of the sub-tank into the bottom piece side oil chamber. On the other hand, a single-tube hydraulic shock absorber uses an orifice drilled in the piston to generate damping force during the push and pull strokes, and compensates for the volume of entry of the piston rod with a high-pressure gas chamber defined by a free piston. It is becoming.

However, when such a conventional hydraulic shock absorber is used in a motorcycle, etc., it is installed in a substantially vertical direction so that when the wheel moves upward, the piston takes a pushing stroke, and when the wheel moves downward, the piston takes a pushing stroke. The piston rod is designed to take a retracting stroke, and it is suitable to reduce the damping force during the pushing stroke and to have the coil spring move in the same direction as the piston rod in order to improve riding comfort. However, as shown in Fig. 1, the hydraulic shock absorber is installed horizontally, that is, approximately in the water direction, and the cylinder side mounting bracket V is connected to the vehicle body W, and the piston rod side mounting bracket X is connected at one end to the axle Y. A configuration for coupling to one end of mechanism Z has recently been developed. In such a horizontal hydraulic shock absorber, the stroke width of the piston rod is smaller than when the piston rod is installed in the vertical direction, and the hydraulic shock absorber can be made smaller. When the hydraulic shock absorber is placed horizontally in this way, the piston works as a pull stroke when the wheel moves up, and works as a push stroke when the wheel moves down, and the damping during the push stroke is The force is higher, and the movement of the coil spring is opposite to that of the piston rod, ie, it extends during the push stroke and contracts during the pull stroke.

Hydraulic shock absorbers configured in this way are used, for example, in swing arm type rear suspensions, but because the coil springs installed around the outer periphery of the cylinder are exposed to the outside, they can easily be bounced up by rain or by the front wheels. Stones and the like can directly hit the coil spring and cylinder, causing corrosion and damage at an early stage.Furthermore, since both ends of the coil spring are fixed to the piston rod and cylinder, it is not possible to adjust the spring load of the coil spring. .

The present invention aims to provide a hydraulic shock absorber that solves the problems of the prior art described above, and the hydraulic shock absorber according to the present invention has a piston at its tip that slides inside a cylinder. A hydraulic shock absorber in which a piston rod is extended from one end of a cylinder, a piston sliding inside the cylinder generates a damping force, and the damping force is increased during a pushing stroke, and the damping force is increased during a pushing stroke, and the hydraulic shock absorber is provided so as to be wound around the outer periphery of the cylinder. The coil spring is stretched between a first spring holder fixed to one end of the cylinder and a second spring holder that can slide on the outer periphery of the cylinder, and the second spring holder is attached to the outer periphery of the coil spring. The main feature is that the coil spring is provided at the other end of the spring case with one end attached to the piston rod, the coil spring is surrounded by the spring case to protect the coil spring and the cylinder, and the spring load of the coil spring can be adjusted. This makes it possible to reduce the size of the hydraulic shock absorber itself, and it does not depend much on the mounting position.

Next, embodiments of the hydraulic shock absorber of the present invention will be described based on the attached drawings. The drawing is a sectional side view of a main part of a double tube type hydraulic shock absorber which is an embodiment of the present invention.

In the illustrated embodiment, the hydraulic shock absorber is constructed as a double-tube type having a cylinder 1 and an inner cylinder 2 of the shock absorber,
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 formed which opens into a piston rod side oil chamber B formed between the piston 13 and a closing portion that closes off the open end of the cylinder 1. Reference numeral 5 denotes a bottom piece, which has an oil chamber A at the end of the inner cylinder 2 so as to form an oil chamber A between it and the bottom plate 4.
- Fitted in an oil-tight manner by a ring 8, an oil passage 9 for the pushing stroke is provided, and a check valve 10 is provided on the oil chamber A side of the oil passage 9 to open only during the pushing stroke. In addition, there is an oil passage 11 for the retraction stroke and a check valve 12 that operates to open only during the retraction stroke on the bottom piece side oil chamber C side formed between the bottom piece 5 and the piston 13 of the oil passage 11. is provided. The piston 13 is provided with an oil passage 14 for the retraction stroke, and a check valve 15 that operates to open only during the retraction stroke is held on the bottom piece side oil chamber C side of the oil passage 14 by a spring 16. , is attached to the tip of the piston rod 17 so as to be slidable within the inner cylinder 2.

Therefore, the piston 13 forms a bottom piece side oil chamber C with the bottom piece 5, and forms a piston rod side oil chamber B with a stopper rubber 21, which will be described later, on the opposite side. 18 is a closing member for the cylinder 1, which closes the open end of the cylinder 1 like a normal shock absorber, through which the piston rod 17 passes, and an oil seal 19 and an inner cylinder 2 are installed inside the cylinder 1. A rod guide 20, a stopper rubber 21, etc., which also close the rod are provided in succession. Reference numeral 22 denotes a coil spring, which 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 that surrounds the outer periphery of the coil spring 22, one end of which is fixed to, for example, a spring adjuster 26 that abuts the spring receiver 24 and is slidably fitted to the outer periphery of the cylinder 1; Alternatively, a disc is directly fixed to the spring receiver 24, and the other end is tightly fixed to the piston rod 17 by a lock nut 27 on the outside of the closing member 18, and is in contact with the rebound rubber 28 on the closing member 18 side. It is threadedly engaged with the outer circumferential screw of the spring adjusting plate 29 having a shape. The outer periphery of the spring adjustment plate 29 is securely locked to the other end of the spring case 25 by a lock nut 30 that is tightly secured.

Incidentally, a recess or a hole 31 having an appropriate shape may be provided at an appropriate location on the outer circumferential surface of the spring case, and a claw of a tool for rotating the spring case 25 may be hooked thereto.

Since the hydraulic shock absorber of the present invention is configured in this way, when used in a motorcycle, the cylinder 1
If the side mounting bracket V is connected to the vehicle body W and the piston rod 17 side mounting bracket Since the one end connected to the axle also moves upward, the piston rod 17 is pulled out from the cylinder 1 and acts as a retraction stroke. For this reason, the oil in the oil chamber B on the piston rod side is pushed by the piston 13 and a part of it passes through the oil passage 14 for the retraction stroke of the piston 13 to the check valve 1.
5 is pushed open and flows into the bottom piece side oil chamber C, and a part of the oil flows into the oil passage 3 from the oil hole 7 of the inner cylinder 2, thereby generating a damping force during the pulling stroke. do. The oil that has flowed into the oil passage 3 flows into the oil chamber A from the oil hole 6, and flows through the oil passage 11 for the drawing stroke of the bottom piece 5 together with oil from the oil chamber of the sub-tank 32, which is separated from the high-pressure gas chamber by a diaphragm. Then, the check valve 12 is pushed open and the oil chamber C on the bottom piece side is replenished. On the other hand, when the wheel moves downward, the piston rod 17 is pushed into the cylinder 1 and works as a pushing stroke, and the oil in the oil chamber C on the bottom piece side is pushed by the piston 13 and works as a pushing stroke of the bottom piece 5. The check valve 10 is pushed open through the oil passage 9 for use, and the oil flows into the oil chamber A to generate a damping force during the pushing stroke.A part of the oil flows into the oil chamber of the sub-tank 32 and is The piston rod 1 is moved by the high pressure gas chamber.
7 is compensated for, and a portion is replenished from the oil hole 6 of the inner cylinder 2 through the oil passage 3 into the piston rod side oil chamber B through the oil hole. However, during the pushing stroke, the oil in the oil chamber C is
Because the oil cannot pass through the oil passage 14 of the piston 13 due to It is what it is.

On the other hand, the coil spring 22 provided on the outer periphery of the cylinder 1 has one end fixed to the closing member 18 and a spring receiver 24 fixed to the other end of the spring case 25 screwed to the spring adjustment plate 29 on the piston rod 17 side. Since it is stretched between the tab spring support 23,
During the pulling stroke of the piston 13 as the wheel moves upward, as the piston rod 17 is pulled out from the cylinder 1, the spring case 25 is pulled and the coil spring 22 is compressed. During the stroke, the coil spring 22 operates to expand as the piston rod 17 is pushed in.

In addition, by rotating the spring case 25,
The attachment length of the coil spring 22 can be adjusted, and the spring load can be adjusted. On this occasion,
It is also possible to provide the spring case 25 with a recess or hole 31 into which a suitable tool can be engaged, so that the spring case 25 can be rotated by the tool.

Although the structure and operation of the present invention have been explained with respect to a double tube type hydraulic shock absorber as shown in the drawings, it is also applicable to a single tube type cylinder fitted with a coil spring. At the same time, a free piston is slidably provided in the oil chamber C side opposite to the piston rod 17 in the cylinder, and the free piston divides the inside of the cylinder into a high pressure gas chamber and an oil chamber. It can also be configured to compensate for the entry volume.

As described above, according to the present invention, when the horizontal hydraulic shock absorber is used particularly as a swing arm type rear suspension, the coil spring and the cylinder are surrounded by the spring case, so that rain or stones thrown up by the front wheels, etc. Not only can the spring load be easily adjusted by simply rotating the spring case, but it also has the same effects as conventional horizontal hydraulic shock absorbers, namely:
Since the stroke width of the piston rod is narrow, the hydraulic shock absorber can be made smaller, and the hydraulic shock absorber can be installed offset from the center line of the vehicle body, or shifted downward, so that the hydraulic shock absorber can be installed offset from the center line of the vehicle body. Effects such as making it possible to take up space required for engine parts batteries, electrical parts, etc. can also be achieved.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the principle of a horizontally placed hydraulic shock absorber, and FIG. 2 is a cross-sectional side view of essential parts of a double tube type hydraulic shock absorber according to an embodiment of 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 ... (For pushing stroke) oil path,
10... (for push stroke) check valve, 11... (for pull stroke) oil passage, 12... (for push stroke) check valve, 13...
...Piston, 14... (for pulling stroke) oil passage, 15...
...(For retraction stroke) Check valve, 16... Spring, 17...
Piston rod, 18... Closing member, 19... Oil seal, 20... Rod guide, 21... Stopper rubber, 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 nut, 31 ... Recess or hole, 32 ... Sub tank, A ... Oil chamber (between the bottom plate and bottom piece), B ... Piston rod side oil chamber, C ... Bottom piece side oil chamber, V, X...Mounting bracket.

Claims (1)

[Claims] 1. A hydraulic shock absorber in which a piston rod having a piston at its tip that slides inside the cylinder is extended from one end of the cylinder, a damping force is generated by the piston sliding inside the cylinder, and the damping force is increased during the pushing stroke, The coil spring provided so as to wind around the outer periphery of the cylinder is stretched between a first spring holder fixed to one end of the cylinder and a second spring holder that can slide on the outer periphery of the cylinder. A hydraulic shock absorber characterized in that a second spring receiver is provided at the other end of the spring case which is wrapped around the outer periphery of the coil spring and whose one end is attached to the piston rod.