JPH0613311B2 - Hydraulic shock absorber for rear wheel suspension of motorcycles - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a hydraulic shock absorber that variably controls a damping force according to a displacement amount of a wheel with respect to a vehicle body.

(Prior art and its problems) Generally, a hydraulic shock absorber provided in a motorcycle or the like generates a damping force according to the contracting speed of a damper, but when cornering or when the weight of a vehicle body is large. In addition, the grounding property of the wheel is improved, or the bottom of the piston is prevented when the wheel receives a large impact, so the damping force is increased according to the displacement amount of the wheel (contraction amount of the damper). Is desirable.

Conventionally, as this type of hydraulic shock absorber, for example, JP-A-55-1
The one disclosed in Japanese Patent No. 5372 has a variable damping mechanism in a tank that stores excess hydraulic oil corresponding to the piston rod intrusion volume associated with the expansion and contraction operation of the damper. It adjusts the resistance applied to the hydraulic oil, and is linked to a free piston that defines a gas chamber in the tank. Since the free piston is displaced along with the inflow of excess hydraulic oil, the damping force can be automatically increased according to the contraction amount of the damper.

However, since the position of the free piston in the tank changes depending on the temperature of the gas chamber, there is a problem that the damping force characteristics differ depending on the temperature condition of the tank, and because the valve mechanism is provided in the tank, There is a problem that it is difficult to adjust the damping force characteristic from the outside.

In addition, as the Japanese Patent Application No. 60-129526,
A tank separated from the damper is connected to one of the vehicle body side and the unsprung member, and a detection rod that slidably projects from this tank and controls the damping force is connected to either the unsprung member or the vehicle body side. In this way, it has already been proposed to stably control the damping force depending only on the amount of displacement of the wheels, but in this case, the structure in which the detection rod is projected from the tank limits the installation space of the vehicle body. Therefore, there was a problem that it was difficult to put it into practical use.

The present invention aims to solve the above problems.

(Means for Solving Problems) According to the present invention, a damper is connected between a vehicle body and an unsprung member that interlocks with a displacement of a wheel, and a surplus actuating portion corresponding to an intruding volume of a piston rod of the damper is provided. In a hydraulic shock absorber equipped with a tank for accumulating, a sensor valve is provided in the middle of an oil passage connecting the damper and the tank, and this sensor valve has a variable damping mechanism for varying the resistance applied to the flow of the excess hydraulic oil, A detection rod that slidably projects from the main body in conjunction with the variable damping mechanism is provided, the main body of the sensor valve is connected to either one of the vehicle body and the unsprung member, and the detection rod is connected to the unsprung member. It is connected to either the vehicle body or the other.

(Operation) As described above, the sensor valve connects the detection rod protruding from the main body to the unsprung member substantially in parallel with the damper, so that the variable damping mechanism directly detects the displacement of the wheel via the detection rod. The damping force can be controlled stably without depending on the temperature in the tank and only on the displacement of the wheels.
Further, if the protruding portion of the detection rod is provided with an adjusting mechanism whose length can be adjusted from the outside, the damping force characteristic can be easily changed.

Further, by forming the sensor valve separately from the damper and the tank, the sensor valve can be made compact, and it is easy to put the sensor valve into practical use without changing the design of the vehicle body or the damper.

(Example) Hereinafter, an example of the present invention is described based on an accompanying drawing.

As shown in FIG. 1, a damper 34 is connected between a motorcycle body 31 and a swing arm (unsprung member) 33 that supports a rear wheel 32.

The tank 35 for storing the surplus hydraulic oil of the damper 34 is formed separately from the damper 34 and attached to the vehicle body 31.

Between the damper 34 and the tank 35, hoses 37 and 38
The sensor valve 36 is disposed via the.

The sensor valve 36 is formed by separating the main body 1 thereof from the damper 34 and the tank 35, and the base end of the main body 1 is pivotally attached to the vehicle body 31 via a pin 42, while slidably protruding from the main body 1. Swing arm 33 for detecting rod 14
It is pivotally attached via a pin 43.

As shown in FIG. 2, the sensor valve 36 has a bearing 10 screwed into the open end of a bottomed cylindrical main body 1 (cylinder), and the bearing 10 is tightened and fixed via a nut 16. An O-ring 13 is provided on the outer peripheral surface of the bearing 10 to seal the inside of the main body 1.

A detection rod 14 is slidably passed through the bearing 10 via an oil seal 12.

An annular first valve seat 2 and a second valve seat 6 are fixed to the inside of the main body 1 via a spacer 5 and a nut 7.

A hose 37 is connected to the main body 1 to form a port 71 communicating with the damper 34, and the spacer 5 is provided with the port 71.
And a plurality of ports 73 are formed, and an oil chamber 74 for opening the port 73 is defined between the first valve seat 2 and the second valve seat 6.

A hose 38 is connected to the main body 1 to form a port 80 communicating with the tank 35, and an oil chamber 79 for opening the port 80 is defined by the first valve seat 2.

In the valve body portion 21 of the detection rod 14 to be inserted into the first valve seat 2 and the second valve seat 6, a shaft hole 77 opening to the oil chamber 79 is formed, and communicates with the shaft hole 77 via the port 76. The oil chamber 75 is defined by the second valve seat 6.

A plurality of ports 81 are formed in the first valve seat 2, and a non-return valve 3 which is seated via a leaf spring 4 is provided. The non-return valve 3 opens for the hydraulic oil returning from the tank 35 to the damper 34.

A plurality of ports 82 are formed in the second valve seat 6, and a relief valve 8 seated via a spring 9 is provided.

The valve body portion 21 of the detection rod 14 is formed with a plurality of orifices 78 that are open at predetermined intervals in the axial direction. The number of orifices 78 opened in the oil chamber 74 between the first valve seat 2 and the second valve seat 6 changes according to the stroke of the detection rod 14, and the resistance imparted to the flow of excess hydraulic oil is made variable. The variable damping mechanism 22 is configured.

A bracket 27 pivotally supporting the pin 39 is connected to the protruding end of the detection rod 14 via a turnbuckle 17, and the turnbuckle 17 is fastened and fixed via lock nuts 18 and 19. By changing the screwing position of the turnbuckle 17, the initial position of the detection rod 14 with respect to the second valve seat 6 can be adjusted.

A spring pin 15 is fitted in the middle of the detection rod 14 to prevent it from being pulled out during assembly.

A bracket 2 for pivotally supporting the pin 38 at one end of the main body 1.
8 is integrally formed.

It is configured in this way, and the operation will be described next.

For example, when the rear wheel 32 rides on a road surface protrusion or the like, as the damper 34 contracts, excess hydraulic oil corresponding to the intruding volume of the piston rod (not shown) from the damper 34 is transmitted through the hose 37 to the sensor. It is guided to the valve 36, passes through the sensor valve 36, and then flows into the tank 35 through the hose 38.

In the sensor valve 36, the excess hydraulic oil guided by the hose 37 is the port 71, the annular gap 72, the port 73.
After flowing into the oil chamber 74 through the orifice 78, it is guided to the hose 38 through the orifice 78, the shaft hole 77, the oil chamber 79 and the port 80.

Since the detection rod 14 is attached to the swing arm 33 substantially in parallel with the damper 34, the detection rod 14 enters the main body 1 in proportion to the contraction amount (stroke amount) of the damper 34.

At this time, depending on the stroke position of the damper 34, the number of orifices 78 formed in the detection rod 14 opening in the oil chamber 74 between the first valve seat 2 and the second valve seat 6 is reduced, and the orifice 78 passes through the orifice 78. The resistance applied to the excess hydraulic oil is increased, and this flow is blocked near the maximum stroke.

When the pressure in the oil chamber 74 rises above the set value, the relief valve 8 opens against the spring 9 and the oil chamber 7
5, it is guided to the hose 38 via the port 76, the shaft hole 77, the oil chamber 79, and the port 80.

FIG. 3 shows damping force characteristics according to the stroke amount of the damper 34, but the stroke amount of the damper 34 is S
Within a predetermined range of ~ R, the compression side damping force is applied to the damper 34.
It can be increased according to the stroke amount of.

In addition, the turnbuckle 17 is adjusted to detect the detection rod 14
By changing the initial position with respect to the main body 1, the point S at which the damping force starts increasing in FIG. 3 and the relief point R at which the relief valve 8 opens can be freely changed.

Further, by loosening the nut 16 and adjusting the screwing position of the bearing 10 with respect to the main body 1, the initial load of the spring 9 can be changed, and the relief valve at the point R at which the increase of the damping force ends in FIG. The valve opening pressure of 8 is also F ₁ ,
You can freely change it to F ₂ or F ₃ .

In this way, by transmitting the displacement (stroke) of the rear wheel 32 to the variable damping mechanism 22 via the link mechanism including the swing arm 33 and the detection rod 14, the damping force control influences the temperature condition of the tank 35. It is possible to do it stably without being done.

Furthermore, since the sensor valve 36 is formed separately from the damper 34 and the tank 35, the sensor valve 36 can be made compact, and a sufficient mounting space can be secured between the vehicle body 1 and the swing arm 33, which facilitates practical application. To do.

On the other hand, during the expansion side operation of the damper 34, the hydraulic oil accumulated in the tank 35 is guided to the sensor valve 36 via the hose 38, passes through the sensor valve 36, and then returns to the damper 34 via the hose 37. At this time, the sensor valve 3
6, the working oil flowing into the oil chamber 79 via the port 80 flows into the oil chamber 74 from the shaft hole 77 through the orifice 78, and also opens the non-return valve 3 to flow into the oil chamber 74 with almost no resistance. .

In another embodiment shown in FIG. 4, two taper grooves 23 are formed on the outer peripheral surface of the valve body portion 21 of the detection rod 14, and the opening area of the taper groove 23 is defined as the inner peripheral surface of the first valve seat 2. The variable damping mechanism 22 is configured by narrowing down with.

In this case, depending on the shape of the tapered groove 23, the detection rod 1
The damping force can be continuously adjusted according to the stroke of 4.

Next, another embodiment shown in FIG. 5 is the detection rod 14 connected to the swing arm 33 via the bracket 27.
And the valve body portion 24 having the plurality of orifices 78 are formed separately.

One end of the valve body portion 24 is biased by a return spring 38 via a retainer 37, and the other end is formed into a taper shape so as to abut against a recess 25 formed on the end face of the detection rod 14, so that the rear wheel Is transmitted to the valve body portion 24 by the detection rod 14.

A ring 39 is fitted to the end of the detection rod 14 to prevent it from coming off.

In this case, by forming the valve body portion 24 separately, it is possible to improve the processing accuracy and the assembly accuracy, and improve the quality.

Next, in another embodiment shown in FIG. 6, the damper 34 is integrally provided with a tank, and the piston 52 is housed in the inner tube 51, while the outer tube 53 of the outer tube 53 is provided outside the inner tube 51. An oil reservoir chamber 54 in which a gas is enclosed is defined. A base valve 55 is provided at the lower end of the inner tube 51, and excess hydraulic oil corresponding to the intrusion volume of the piston rod 56 that flows out through the base valve 55 is guided to the sensor valve 36 via a hose 57.
The hydraulic oil that has passed through the sensor valve 36 flows into the oil reservoir chamber 54 via the hose 58.

The bracket 60 formed on the piston rod 56 and the bracket 61 formed on the detection rod 14 of the sensor valve 36 are connected to the swing arm 33, respectively, while the bracket 62 fixed to the lower ends of the outer tube 53 and the inner tube 51. And the sensor valve 36
The brackets 63 formed on the body 1 of the
It is connected to the 1 side.

In this case as well, since the sensor valve 36 is formed separately from the tank, it is possible to assemble the damper integrally with the tank by changing the design of some components.

As described above, according to the present invention, the sensor valve is provided in the middle of the oil passage for guiding the surplus hydraulic oil of the damper to the tank, and the detection rod of the sensor valve responds to the displacement of the unsprung member with respect to the vehicle body. In addition, a variable damping mechanism that adjusts the damping force according to the stroke of the detection rod is provided, so that the damping force is stabilized only by the displacement amount of the wheels without being affected by the temperature conditions of the tank etc. The damping force characteristics can be easily changed by adjusting the length of the detection rod from the outside, and the sensor valve can be made separate from the damper and tank to make the sensor valve compact. However, there is an effect that the practical use is facilitated without requiring a large design change in the vehicle body or the damper.

[Brief description of drawings]

FIG. 1 is a side view showing an embodiment of the present invention, FIG. 2 is a sectional view of the same sensor valve, and FIG. 3 is a graph showing damping force characteristics. FIG. 4 is a sectional view showing another embodiment. FIG. 5 is a sectional view of a sensor valve showing another embodiment. FIG. 6 is a block diagram showing still another embodiment. 1 ... Main body, 14 ... Detection rod, 22 ... Variable damping mechanism, 31 ... Car body, 32 ... Rear wheel, 33 ... Swing arm, 34 ... Damper, 35 ... Tank, 36 ... Sensor valve

Claims (1)

[Claims] 1. A hydraulic shock absorber, comprising a damper connected between a vehicle body and an unsprung member interlocking with the displacement of wheels, the tank including a tank for storing excess hydraulic oil corresponding to an intrusion volume of a piston rod of the damper. , A sensor valve is provided in the middle of the oil passage connecting the damper and the tank, and this sensor valve works in conjunction with a variable damping mechanism that makes variable the resistance applied to the flow of the excess hydraulic oil, and this variable damping mechanism. A detection rod slidably protruding from the main body is provided, and the sensor valve main body is connected to either one of the vehicle body and the unsprung member, and the detection rod is connected to the other one of the unsprung member and the vehicle body. A hydraulic shock absorber characterized in that