JPH0756312B2 - Anti-dive suspension unit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION a. Field of Industrial Application The present invention relates to an anti-dive suspension unit for an automobile, and in particular, a valve case is detachably attached to a lower end portion of a suspension unit using an oil damper,
The present invention relates to a suspension unit in which valves for performing anti-dive action are collectively stored in this valve case.

b. Conventional Technology As an anti-dive device for a suspension unit using an oil damper, for example, the technology shown in FIGS. 5 and 6 is already known (see Japanese Patent Publication No. 57-34148). This anti-dive device is applied to a front fork 1 of a two-wheeled automobile, and in FIG.
Is a fork pipe and 3 is a bottom case. A seat pipe 4 is erected coaxially in the bottom case 3, and the fork pipe 2 is slidably fitted around the outer periphery of a flange 4a at the upper end of the seat pipe 4. An oil lock collar 5 attached to the lower end of the fork pipe 2 is slidably fitted on the outer peripheral surface of the seat pipe 4.

A reserve chamber 6 is formed inside the seat pipe 4, and a hydraulic pressure generating chamber 7 is provided between the seat pipe 4 and the bottom case 3.
Are formed. These reserve chamber 6 and hydraulic pressure generating chamber 7
Are communicated with each other by an oil passage 8, and a hydraulically controlled valve 9 is arranged facing the oil passage 8. This valve 9
Is connected to the hydraulic pressure generator 11 by the tube 10, the braking reaction force received by the brake caliper 12 during braking acts on the piston 11a of the hydraulic pressure generator 11 via the arm 13, and the hydraulic pressure generated as a result is transmitted via the tube 10. It is configured to act on the valve 9 to close the valve 9. The sixth
In the figure, 14 and 15 are check valves.

In the above-mentioned anti-dive device, the valve 9 is used during braking.
Is closed, the oil flow between the reserve chamber 6 and the hydraulic pressure generating chamber 7 is restricted, and therefore the sinking of the fork pipe 2 is suppressed. At this time, when the fork pipe 2 is relatively lowered due to the unevenness of the road surface, the pressure in the hydraulic pressure generating chamber 7 rises, the valve 9 is pushed open, and a part of the oil is reserved in the reserve chamber 6.
Flow into. Further, when the fork pipe 2 relatively rises, a part of the oil in the reserve chamber 6 flows into the hydraulic pressure generation chamber 7 through the check valve 15.

c. Problems to be Solved by the Invention A conventional anti-dive device is constructed, for example, as described above, but this device is compared with a front fork of a motorcycle having a relatively large space in the vertical direction. Although it can be applied easily, there is the following inconvenience in application when there is not enough space in the vertical direction like a suspension unit of a four-wheeled vehicle. That is, in the conventional device, since the check valve 15 is arranged below the bottom case 3, the effective stroke of the fork pipe 2 is reduced by the space for disposing the check valve 15, and the suspension performance is impaired. In addition, since the check valve 15 is arranged in the bottom case 3, there is a problem in terms of maintenance.

The present invention has been made in view of the above circumstances, and an object thereof is an anti-dive suspension unit for an automobile, which can secure an effective stroke of a suspension as long as possible and easily maintain valves. To provide.

d. Means for Solving the Problems In order to solve the above-mentioned problems, the present invention fits the inner cylinder with a predetermined gap inside the outer cylinder connected to the axle, and the inner cylinder An oil reserve chamber and a buffer pressure chamber are formed between the inner and outer cylinders respectively.A piston is fitted inside the inner cylinder, the piston and the vehicle body are connected by a piston rod, and the outer peripheral surface of the outer cylinder is formed. The lower end of the coil spring is fastened to the upper end of the piston rod, the valve case is attached to the lower end of the outer cylinder, and the outer cylinder is attached to the side of the outer cylinder. At least the first, second and third parts are attached to the partition plate which is detachably attached to the cylinder substantially in parallel and which divides the upper and lower chambers in the valve case.
Three passages are formed in parallel and substantially parallel to the outer cylinder, and the lower ends of the oil reserve chamber and the buffer pressure chamber are communicated with each other by these three passages,
A hydraulically controlled on-off valve is provided in the first passage, and the second passage is provided.
Is provided with a relief valve that allows an oil flow from the oil reserve chamber to the buffer pressure chamber at a predetermined pressure or more, and a check valve that blocks the oil flow from the oil reserve chamber to the buffer pressure chamber in the third passage. A valve is provided, a control hydraulic pressure port of the on-off valve is arranged below the valve case, and a brake operating pressure is introduced into the control hydraulic pressure port.

e. Operation In the anti-dive suspension unit configured as described above, the valves are stored together in the valve case, so maintenance of the valves is easy and the valve is not installed in the cylinder. Therefore, the structure of the cylinder is simple, and the piston stroke can be secured over almost the entire length of the cylinder.The control hydraulic port of the on-off valve is located below the valve case, so The lower end of the coil spring that is fixed does not interfere with the control hydraulic port, and therefore the required total length of the coil spring can be secured with a margin.
The suspension performance can be improved in combination with ensuring the piston stroke described above.

f. Example One example of the present invention will be described below with reference to FIGS. 1 to 4. First, FIG. 1 shows a saddle-ride type four-wheel vehicle 21 for traveling on rough terrain to which the present invention is applied. In this four-wheeled vehicle 21, two wheels each of a front wheel 23 and a rear wheel 24 are provided on a vehicle body frame 22 configured in a so-called saddle type. Low-pressure balloon tires are used for the wheels 23 and 24 so that the wheels 23 and 24 can travel freely even in a muddy area, a puddle, or a shallow river.

A double wishbone type is usually adopted for the suspension of the wheels 23 and 24. FIG. 2 shows a suspension of the front wheel 23, which is supported by an upper arm 25 and a lower arm 26. The anti-dive suspension unit 27 according to the present invention is arranged between the vehicle body frame 22 and the lower arm 26. In FIG. 2, 28 is a brake lever, 29 is a master cylinder, 30 is a 3-way joint, and 31 is a disc brake caliper.

The suspension unit 27 uses an oil damper 35 and a coil spring 36 together as shown in FIG. Specifically, the oil damper 35 is configured by disposing an inner cylinder 38 in an outer cylinder 37 with a predetermined gap, and fitting a piston 39 into the inner cylinder 38. In addition, this piston 39
Is connected to the vehicle body frame 22 via a piston rod 40, and the lower end of the outer cylinder 37 is connected to the lower arm 26.

Bushings 41 and 42 are fitted in the cylinder mutual gaps at the upper and lower ends of the inner and outer cylinders 37 and 38, respectively, and independent oil reserve chambers 43 and buffer pressure chambers 44 are formed inside and outside the inner cylinder 38, respectively. There is. On the other hand, a cylindrical valve case 48 is detachably attached to the outer peripheral surface of the lower end portion of the outer cylinder 37 by bolts or the like as shown in FIGS. The interior of the valve case 48 is divided into two upper and lower chambers 50 and 51 by a partition plate 49, the upper chamber 50 is communicated with the buffer pressure chamber 44 by a passage 52, and the lower chamber 51 is divided by a passage 53 into an oil reserve chamber 43. It is in communication with.

At the center of the partition plate 49, a cylindrical center piece 56 is arranged so as to penetrate in the vertical direction. This centerpiece 56
A first passage 57 is formed inside the chamber along the central axis thereof, and the upper and lower chambers 50, 51 are communicated with each other by the first passage 57. The nozzle 57a is provided in the middle of the first passage.
Are formed.

A valve seat hole 58 is formed at the lower end of the first passage 57,
The valve seat hole 58 is opened and closed by a hydraulically controlled on-off valve 59. The on-off valve 59 is vertically slidably fitted to an end cap 60 that closes the lower end of the valve case 48. Open / close valve 59 and center piece
A spring 61 is arranged between the flange portion 56a of 56 and the opening / closing valve 59 is always urged downward by the spring 61.

A plunger housing 65 is attached to the lower end of the valve case 48. Plunger inside this housing 65
66 is arranged so that it can move up and down, and the upper end of this plunger 66
66a is always in contact with the lower end of the on-off valve 59, and the plunger 6
A lower end 66b of 6 projects into the hydraulic chamber 67. A blind cover 68 is screwed onto the lower end of the plunger housing 65,
The blind chamber 68 closes the hydraulic chamber 67.

The hydraulic chamber 67 is a hydraulic port located below the valve case 48.
The hydraulic port 69 is connected to the 3-way joint 30 or the caliper 31 by a tube 70. Then, the brake operating pressure at the time of braking is introduced into the hydraulic chamber 67.

Since the hydraulic port 69 is considerably separated from the coil spring 36, there is no possibility that the coil spring 36 will interfere with the circling of the tube 70.

A plurality of second passages 73 are formed so as to penetrate in the vertical direction around the center piece 56 of the partition plate 49 on the same circumference. On the other hand, a cylindrical relief valve 75 is slidably fitted to the outer periphery of the center piece 56 via a spacer 74. This relief valve 75 is constantly urged downward by a spring 76,
The second passage 73 is normally closed by the flange portion 75a of the relief valve 75.

Around the center piece 56 of the partition plate 49, a plurality of third passages 77 are vertically formed so as to extend on the same circumference further outside the second passage 73. Meanwhile, the partition plate 49
A check valve 78 in the form of a ring plate is disposed on the lower surface of the. The check valve 78 is constantly urged upward by the spring 79, and the third passage 77 is normally closed by the check valve 78. The check valve 78 has notches 80 formed at several positions so as not to block the second passage 73.

As described above, in the suspension unit 27 according to the present invention, since the valves are collectively stored in the detachable valve case 48, the maintenance of the valves can be facilitated and the outer cylinder 37 as in the conventional case can be achieved. Since the check valve is not provided at the lower end of the piston, the stroke of the piston 39 can be set relatively large, and the suspension performance can be improved.

A coil spring 36 is arranged between the outer cylinder 37 and the upper end of the piston rod 40 as shown in FIG. The coil spring 36 reinforces the buffering force of the oil damper 35, and the lower end portion of the coil spring 36 is fixed to a spring seat 84 near the upper portion of the valve case 48 on the outer peripheral surface of the outer cylinder 37. The upper end of the coil spring 36 is fixed to the flange 85a at the upper end of the protective sleeve 85.

The anti-dive suspension unit 27 is configured as described above, and since the brake operating pressure does not act on the hydraulic chamber 67 during normal traveling, the opening / closing valve 59 is open as shown in FIGS. 3 and 4. In this state, when the piston rod 40 moves up and down relatively, the coil spring 36 serves as a buffer, and the oil reserve chamber passes through the first passage 57.
Oil flows between 43 and the buffer pressure chamber 44, and the air stored in the upper portion of the buffer pressure chamber 44 serves as a buffering action.

On the other hand, during braking, the brake operating pressure is introduced into the hydraulic chamber 67, and the pressure causes the plunger 66 to push up the on-off valve 59 against the spring 61 and close the valve seat hole 58. Therefore, the flow of oil through the first passage 57 is blocked, and the sinking of the piston rod 40 is blocked. At this time, when a vertical impact force acts on the outer cylinder 37 due to the unevenness of the road surface, the oil flows through the second passage 73 and the third passage 77. The buffering action is performed by.

That is, when an upward force is applied to the outer cylinder 37, the pressure in the oil reserve chamber 43 increases, and this pressure pushes up the relief valve 75 against the spring 76, which causes the oil from the oil reserve chamber 43 to the buffer pressure chamber 44. Flows. When the upward force acting on the outer cylinder is released, the coil spring
The pressure of the oil reserve chamber 43 is reduced by the force of 36, and the oil in the buffer pressure chamber 44 receives the air pressure above it and the check valve
The spring 78 is pushed open against the spring 79 and flows into the oil reserve chamber 43. Thus, the vertical vibration of the piston rod is allowed even during anti-dive, so that the suspension performance during braking can be improved.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment and various modifications can be made. For example, the opening / closing valve 59 and the relief valve 75 in the above embodiment
As the structure of the check valve 78, another structure having an equivalent function may be adopted.

g. Effect of the Invention As described above, the present invention is such that the valve case is detachably attached to the lower end portion of the suspension unit, and the valves necessary for the anti-dive action are collectively stored in this valve case. These valves are easy to maintain, and because no valves are provided inside the cylinder, the structure of the cylinder can be simplified, and the piston stroke can be ensured to be relatively large over almost the entire length of the cylinder. An improvement in suspension performance can be achieved. Further, since the control hydraulic pressure port of the on-off valve that performs the anti-dive action is arranged below the valve case, the lower end of the coil spring fixed to the outer peripheral surface of the outer cylinder does not interfere with the control hydraulic pressure port. Therefore, the required total length of the coil spring can be secured with a margin, and the tube connected to the control hydraulic pressure port can be easily routed because the coil spring does not interfere.

[Brief description of drawings]

1 to 4 show an embodiment of the present invention, in which FIG. 1 is a perspective view of a saddle-ride type four-wheel vehicle for running on uneven terrain, and FIG. Front suspension schematic, 3rd
The figure shows a vertical section of the anti-dive suspension unit.
FIG. 4 is an enlarged vertical sectional view of a lower end portion of the unit. Further, FIG. 5 is a side view of a front fork suspension in a conventional motorcycle, and FIG. 6 is a vertical sectional view of a lower end portion of the suspension.

Claims (1)

[Claims] 1. An inner cylinder is fitted with a predetermined gap inside an outer cylinder connected to an axle, an oil reserve chamber is provided inside the inner cylinder, and a buffer pressure chamber is provided between the inner and outer cylinders. A partition is formed, a piston is fitted inside the inner cylinder, the piston and the vehicle body are connected by a piston rod, the lower end of the coil spring is fixed to the outer peripheral surface of the outer cylinder, and the upper end of the coil spring is connected. Part is fixed to the upper end of the piston rod, the valve case is attached to the lower end of the outer cylinder, and is detachably attached to the side of the outer cylinder almost parallel to the outer cylinder. At least three first, second, and third passages are formed in parallel in a partition plate that divides the upper and lower two chambers and are substantially parallel to the outer cylinder, and the oil reserve chamber is provided with the buffer pressure by these three passages. Of communicating the respective lower end portions to each other, the hydraulic control on-off valve provided in the first passage, the second
A relief valve that allows an oil flow from the oil reserve chamber to the buffer pressure chamber at a predetermined pressure or more is provided in the passage of
Is provided with a check valve for blocking the oil flow from the oil reserve chamber to the buffer pressure chamber, and the control hydraulic port of the opening / closing valve is arranged below the valve case, and the control hydraulic port has a brake. An anti-dive suspension unit characterized by being configured to introduce working pressure.