JPS6122181B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a hydraulic shock absorber used in rear suspensions of motorcycles, etc., which has a variable damping force that allows push-side damping force to be adjusted through a common flow path without affecting pull-side damping force. It is related to the device.

Hydraulic shock absorbers have a piston at the tip of the piston rod that is slidably inserted into the cylinder, and an oil passage and a valve mechanism provided in the piston are used to obtain damping forces during the compression stroke and extension stroke. An oil flow path communicating from a lower oil chamber to an upper oil chamber of the cylinder is formed inside, and the opposing gap between the tapered circumferential surface of the tip of an adjustment rod inserted into the hollow interior of the piston rod and the stepped portion of the oil passage is adjusted. This makes it possible to specifically vary the damping force.

However, in the conventional damping force adjustment mechanism of this type, the oil flow path where the flow rate is adjusted is a common flow path during both the compression stroke and the extension stroke of the shock absorber. There was a problem in that the damping force of the stroke also changed in the same way, making it impossible to obtain a damping force that matched the desired feeling.

Therefore, in order to solve this problem, oil is added to the oil flow path of the piston rod in accordance with the extension stroke of the shock absorber so that the damping force in the compression stroke or extension stroke can be varied without affecting the other damping force. Some devices are equipped with a check valve that opens and closes the flow path, but the configuration is complicated, the number of parts is large, assembly is not easy, and it is impossible to make the flow path large due to space and strength issues. There were some problems.

Separately, an oil lock collar is fitted to the end of the cylinder and an oil lock piece is attached to the outer periphery of the piston rod to activate the oil lock during the shock absorber's extension stroke, thereby preventing impact when the shock absorber is fully extended. There are some that are equipped with. In this type of device, a check valve that opens during the compression stroke and closes during the extension stroke is provided in the piece so that the oil lock piece can be smoothly removed from the oil lock collar when moving to the next compression stroke.

The present invention combines this type of hydraulic shock absorber with an oil lock mechanism with a conventional hollow rod type damping force adjustment device, thereby replacing the check valve inside the hollow rod with the check valve inside the oil lock piece. Therefore, the oil passage of the oil lock piece is made to serve both as an oil passage for generating a damping force and an oil passage for the oil lock mechanism. An embodiment of the present invention will be described in detail below with reference to the drawings.

The figure is a partially cutaway sectional view showing an embodiment of a damping force variable device for a hydraulic shock absorber according to the present invention. In the figure,
1, a piston 3 fitted to the tip of a piston rod 2 is slidably fitted into a cylinder 4 filled with oil, and a coil spring 6 is stretched between the installed base 5 of the piston rod 2 and the cylinder 4. It is a hydraulic shock absorber made of oil holes 7 and 8 provided in the piston 3.
The valve members 9 and 10 provide damping force for the compression stroke and extension stroke. The inside of this piston rod 2 is formed hollow, and an enlarged diameter oil passage 11 is formed in the upper part of the piston rod 2.
A diameter-reducing stepped portion 12 is provided at the upper portion of the oil chamber 1, and is connected to the upper oil chamber A. The hollow interior of the piston rod below this diameter-reducing step 12 has a tapered tip 1.
An adjustment rod 13 formed at 3' is fitted therein.
This adjusting rod 13 brings the circumferential surface of the tapered tapered part 13' toward the diameter-reducing step part 12 with a gap therebetween, and has its rear end screwed into the adjuster star 14 provided at the lower end of the shock absorber 1. The damping force of the shock absorber can be adjusted by adjusting the gap between the stepped portion 12 and the tapered tapered portion 13' of the adjusting rod 13 to control the oil flow rate. It is configured to adjust.

Next, an oil lock piece 15 is fitted to the piston rod 2 below the piston 3, and this oil lock piece 15 prevents impact when the piston is fully extended. A check valve 17 and an oil hole 18 that open during the compression stroke and close during the extension stroke are provided in the piece 15 so that the piece 15 can be smoothly removed from the collar 16, and one end is connected to the oil chamber A through the oil passage 11.
The other end forms an oil passage 19 that communicates with the lower oil chamber B via a check valve 17 for an oil lock mechanism.

In this way, during the extension stroke of the shock absorber, the check valve 17 is closed by the internal pressure of the lower oil chamber B of the cylinder 4, and the oil in the oil passage 11 stops flowing, so that the extension stroke by the oil hole 7 and the valve member 9 is prevented. The damping force is not affected by the damping force adjustment by the adjusting rod 13. On the other hand, during the compression stroke, the check valve 17 opens, so the oil flow path 1
Therefore, the damping force during the compression stroke due to the oil hole 8 and the valve member 10 is caused by the tapered tapered part 13' and the diameter-reduced step part 12 due to the sliding displacement of the adjusting rod 13.
regulated by the bore gap control.

As explained in detail above, the present invention connects the hollow oil passage of the piston rod and the oil passage for the oil lock mechanism, and uses a check valve in the oil lock piece to make the passage only in one direction. This simplifies the structure and requires fewer parts.Moreover, since there are no extra parts or oil passages in the hollow rod or oil lock piece, the oil passage can be made larger, and the damping force can be adjusted within a wider range. It has the effect of widening the

[Brief explanation of the drawing]

The figure is a partially cutaway sectional view showing an embodiment of a damping force variable device for a hydraulic shock absorber according to the present invention. 1...Hydraulic shock absorber, 2...Piston rod, 3
... Piston, 4 ... Cylinder, 11 ... Oil flow path, 12 ... Diameter reduction step, 13 ... Adjustment rod, 1
5...Oil lock piece, 17...Check valve, 1
9...Oil flow path.

Claims (1)

[Claims] 1 Hydraulic buffering in which a hollow piston rod is inserted into the cylinder, a piston equipped with a damping force generator is attached to the tip of the piston rod, and the oil passage inside the rod can be adjusted by an adjustment rod inserted into the rod. In the piston rod, an oil lock piece is fitted under the piston on the outer periphery of the piston rod, and an oil passage communicating with the hollow oil passage in the piston rod is formed inside the oil lock piece, and the oil passage is extended. 1. A variable damping force device for an oil reed shock absorber, characterized in that a check valve is provided to occasionally close the oil passage.