JPS62266242A - Antidive suspension unit - Google Patents

Abstract

PURPOSE:To make the maintenance of valves easy and simplify the structure of a cylinder to improve the performance, by detachably mounting a valve case at a lower end portion, and containing the requisite valves wholly in the valve case. CONSTITUTION:A valve case 48 is mounted at a lower end portion,and valves are wholly contained therein. With this arrangement, the maintenance of the valves is made easy, and as no valves are arranged in an inner cylinder 38, the cylinder structure is simplified, and the stroke of a piston 39 can be ensured over the substantially entire length of the inner cylinder 38. Furthermore, as a control oil pressure opening for the valve is provided at the lower portion of the valve case 48, the lower end of a coil spring 36 fixedly engaged on an outer circumferential surface of an outer cylinder 37 does not interfere with the control oil pressure opening, and a requisite entire length of the coil spring 36 can be sufficiently ensured, thus improving the suspension performance owing to the insurance of the stroke of the piston 39 in combination therewith.

Description

[Detailed Description of the Invention] a. Field of Industrial Application The present invention relates to an anti-dive suspension unit for automobiles, and in particular, a valve case is removably attached to the lower end of a suspension unit using an oil damper.
This is about a suspension unit that houses all the valves that perform anti-dive action inside the 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 is applied to a front fork 1 of a two-wheeled automobile, and in the figure, 2 is a fork pipe and 3 is a bottom case. A seat pipe 4 stands coaxially in the bottom case 3, and a fork pipe 2 is slidably fitted around the outer periphery of a flange portion 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 to the outer peripheral surface of the seat pipe 4.

A reserve chamber 6 is formed inside the seat pipe 4, and a hydraulic pressure generation chamber 7 is formed between the seat pipe 4 and the bottom case 3.
is formed. These reserve chamber 6 and hydraulic pressure generation chamber 7
are communicated with each other by an oil passage 8, and a hydraulically controlled valve 9 is disposed facing this oil passage 8. This valve 9
is connected to a hydraulic pressure generator 11 by a tube 10,
The braking reaction force received by the brake caliper 12 during braking acts on the piston lla of the hydraulic pressure generator 11 via the arm 13, and the resulting hydraulic pressure acts on the valve 9 via the tube 10 to close the valve 9. It is composed of In FIG. 6, 14 and 15 are check valves.

In the above-mentioned anti-dive device, the valve 9 is activated 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 falls relatively due to the unevenness of the road surface, the pressure in the oil pressure generating chamber 7 increases and the valve 9 is pushed open, and a part of the oil is transferred to the reserve chamber 6.
flows into. Also, when the fork pipe 2 rises relatively, some of the oil in the reserve chamber 6 flows into the check valve 15.
The oil flows into the oil pressure generation chamber 7 through the oil pressure generating chamber 7.

C9 Problems to be Solved by the Invention Conventional anti-dive devices are configured, for example, as described above, but this device is relatively difficult to use when there is a relatively large amount of space in the vertical direction, such as the front fork of a motorcycle. Although it is easy to apply, there are the following disadvantages in application when there is not much vertical space, such as in the suspension unit of a four-wheeled vehicle. That is, in the conventional device, since the check valve 15 is disposed at the lower part of the bottom case 3, the effective stroke of the fork pipe 2 is reduced by the space for which the check valve 15 is disposed, which impairs suspension performance. Furthermore, since the check pulp 15 is disposed within the bottom case 3, there is also a problem in its maintenance.

The present invention was devised in view of the above-mentioned circumstances, and its purpose is to provide an anti-dive suspension unit for automobiles that can ensure the effective stroke of the suspension as long as possible and that allows easy maintenance of valves. The purpose is to provide.

d. Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides a method in which an inner cylinder is fitted with a predetermined gap inside an outer cylinder connected to an axle, and the inside of the inner flip is fitted with a predetermined gap. An oil reserve chamber is formed between the inner and outer cylinders, and a buffer pressure chamber is formed between the inner and outer cylinders, a piston is fitted into the inner cylinder, the piston and the vehicle body are connected by a piston rod, and the outer circumferential surface of the outer cylinder is Attach the lower end of the coil spring to the
An upper end of the coil spring is fixed to the upper end of the piston rod, a valve case is removably attached to the lower end of the outer cylinder, and at least a first
．． A second and a third three passages are formed in parallel, and the lower ends of the oil reserve chamber and the buffer pressure chamber are communicated with each other by these three passages, and a hydraulically controlled system is provided in the first passage. a relief valve that allows oil to flow from the oil reserve chamber to the buffer pressure chamber at a predetermined pressure or higher is provided in the second passage; and a relief valve that allows oil to flow from the oil reserve chamber to the buffer pressure chamber in the third passage; A check valve is provided to prevent oil from flowing into the valve case, and a control hydraulic pressure port of the on-off valve is disposed below the valve case, and brake operating pressure is introduced into the control hydraulic pressure port. .

e. Function: In the anti-dive suspension unit configured as described above, the valves are all housed in the valve case, so maintenance of the valves is easy, and no valves are arranged inside the cylinder. This simplifies the structure of the cylinder, and allows the piston stroke to be maintained over almost the entire length of the cylinder.Also, since the control hydraulic port for the on-off valve is located below the valve case, it can be placed on the outer circumferential surface of the outer cylinder. The lower end of the fixed coil spring does not interfere with the control hydraulic port, and therefore the required overall length of the coil spring can be secured with plenty of margin.
Together with securing the above-mentioned piston stroke, it is possible to improve suspension performance.

r. Example An example of the present invention will be described below with reference to FIGS. 1 to 4. First, FIG. 1 shows a straddle-type four-wheeled vehicle 21 for traveling on rough terrain to which the present invention is applied.

This four-wheeled vehicle 21 has two front wheels 23 and two rear wheels 24 on a body frame 22 configured in a so-called straddle type. These wheels 23 and 24 are equipped with low-pressure balloon tires, and are configured so that they can freely run in mud, puddles, or shallow waters of a river.

The suspension of the wheels 23 and 24 usually employs a double wishbone type. Figure 2 shows front wheel 2
3, the front wheel 23
is supported by an upper arm 25 and a lower arm 26. An anti-dive suspension unit 27 according to the present invention is disposed between the vehicle body frame 22 and the lower arm 26.

In FIG. 2, 28 is a brake lever, 29 is a mask cylinder, 30 is a three-way joint, and 31 is a disc brake caliper.

The suspension unit 27 uses an oil damper 35 and a coil spring 36 as shown in FIG.

Specifically, the oil damper 35 has an inner cylinder 38 disposed within an outer cylinder 37 with a predetermined gap therebetween, and a piston 39 fitted into the inner cylinder 38. The 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.

Bushes 4L42 are fitted into the gaps between the cylinders at both the upper and lower ends of the inner and outer cylinders 37 and 38, respectively.
An oil reserve chamber 43 and a buffer pressure chamber 44, which are independent from each other, are defined inside and outside the inner cylinder 38, respectively. On the other hand, on the outer peripheral surface of the lower end of the outer cylinder 37, there are shown figures 3 and 4.
As shown in the figure, a cylindrical valve case 48 is removably attached with bolts or the like. The inside of this valve case 48 is divided into two upper and lower chambers 50 and 51 by a partition plate 49.
The upper chamber 50 communicates with the buffer pressure chamber 44 through a passage 52, and the lower chamber 51 communicates with the oil reserve chamber 43 through a passage 53.

A cylindrical center piece 56 is provided at the center of the partition plate 49.
are arranged to penetrate in the vertical direction. A first passage 57 is formed inside the center piece 56 along its central axis, and the first passage 57 forms upper and lower chambers 50 .
51 are connected. Note that a nozzle portion 57a is formed in the middle of the first passage.

A valve seat hole 58 is formed at the lower end of the first passage 57, and the valve seat hole 58 is opened and closed by a hydraulically controlled on-off valve 59. The on-off valve 59 is fitted into an end cap 60 that closes the lower end of the valve case 48 so as to be slidable in the vertical direction. Also, the on-off valve 5
A spring 61 is disposed between the center piece 9 and the flange portion 56a of the center piece 56, and the on-off valve 59 is always urged downward by the spring 61.

A plunger housing 6 is provided at the lower end of the valve case 48.
5 is installed. A plunger 66 is disposed within the housing 65 so as to be movable up and down.
The upper end 66a of the plunger 66 is always in contact with the lower end of the on-off valve 59, and the lower end 66b of the plunger 66 projects into the hydraulic chamber 67. A blind lid 68 is screwed onto the lower end of the plunger housing 65, and the hydraulic chamber 67 is closed by the blind lid 68.

The hydraulic chamber 67 is communicated with a hydraulic port 69 located below the valve case 48 , and this hydraulic port 69 is connected to the three-way twint 30 or the caliper 3 through a tube 70 .
Connected to 1. Brake generation operating pressure during braking is introduced into the hydraulic chamber 67.

It should be noted that since the hydraulic port 69 is quite far away from the coil spring 36, there is no fear that the coil spring 36 will interfere with the routing of the tube 70.

A plurality of second passages 73 are vertically formed 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 centerpiece 56 via a spacer 74. This relief valve 75 is always urged downward by a spring 76, and the second passage 73 is normally connected to the relief valve 75.
is closed by a flange portion 75a.

Around the center piece 56 of the partition plate 49, the second
A plurality of third passages 77 are formed on the same circumference further outside the passage 73 in the vertical direction. on the other hand,
A ring plate-shaped check valve 78 is disposed on the lower surface of the partition plate 49. This check valve 78 is always urged upward by a spring 79, and the third passage 77 is normally closed by this check valve 78. Note that the check valve 78 has cutouts 80 formed at several locations so as not to block the second passage 73.

In this way, the suspension system unit 27 according to the present invention
Since the valves are all housed in the removable valve case 48, maintenance of the valves can be facilitated, and a check valve is not provided at the lower end of the outer cylinder 37 as in the conventional case. Therefore, the piston 39 stroke can be set relatively thick, and suspension performance can be improved.

A coil spring 36 is disposed between the outer cylinder 37 and the upper end of the piston loft 40, as shown in FIG.

This coil spring 36 reinforces the buffering force of the oil damper 35, and the lower end of the coil spring 36 is fixed to the seat 84 at the spring receiver near the upper part 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 a flange 85a at the upper end of the protective sleeve 85.

The anti-dive suspension unit 27 is constructed as described above, and during normal driving, brake operating pressure does not act on the hydraulic chamber 67. When the piston loft 40 moves up and down relatively in this state, the coil spring 3
6, oil flows between the oil reserve chamber 43 and the buffer pressure chamber 44 via the first passage 57, and the air stored in the upper part of the buffer pressure chamber 44 provides a buffering effect. .

On the other hand, during braking, brake operating pressure is introduced into the hydraulic chamber 67, and this pressure causes the plunger 66 to spring 61.
The valve seat hole 58 is closed by pushing up the on-off valve 59 against the force. Therefore, the flow of oil through the first passage 57 is prevented, and the piston loft 40 is prevented from sinking. At this time, when a vertical impact force is applied to the outer cylinder 37 due to the unevenness of the road surface, oil flows through the second passage 73 and the third passage 77, so that the buffer pressure chamber 44
The air inside provides a buffering effect.

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, causing oil to flow from the oil reserve chamber 43 to the buffer pressure chamber 44. flows. Furthermore, when the upward force acting on the outer cylinder is released, the pressure in the oil reserve chamber 43 decreases due to the force of the coil spring 36, and the oil in the buffer pressure chamber 44 receives air pressure above it, causing the check valve 78 is pushed open against the spring 79 and flows into the oil reserve chamber 43. In this way, vertical vibration of the piston loft is allowed even during anti-dive, and as a result, 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 can be modified in various ways.For example, the on-off valve 59 in the above embodiment. Relief valve 7
5 and the check valve 78 may adopt other structures having equivalent functions.

g. Effects of the Invention As described above, the present invention has a valve case removably attached to the lower end of the suspension unit 7), and valves necessary for anti-dive action are collectively housed within this valve case. The maintenance of these valves is easy, and since there are no valves inside the cylinder, the structure of the cylinder can be simplified, and the piston stroke can be maintained relatively large over almost the entire length of the cylinder. As a result, improvement in the performance of subenzidine can be achieved. In addition, since the control hydraulic port for the on-off valve that performs the anti-dive action is located below the valve case, the lower end of the coil spring fixed to the outer circumferential surface of the outer cylinder will not interfere with the control hydraulic port 4B. Therefore, the required total length of the coil spring can be secured with a sufficient margin, and the tube connected to the control hydraulic pressure port can be easily routed because the coil spring does not interfere.

[Brief explanation of drawings]

1 to 4 show an embodiment of the present invention, in which FIG. 1 is a perspective view of a four-wheeled straddle-type vehicle for traveling on rough terrain, and FIG. 2 is a perspective view of the four-wheeled vehicle. Schematic diagram of the front suspension, 3rd
The figure is a vertical cross-sectional view of the anti-diape suspension unit.
FIG. 4 is an enlarged vertical sectional view of the upper end of the unit. Further, FIG. 5 is a side view of a front fork suspension in a conventional motorcycle, and FIG. 6 is a longitudinal sectional view of the lower end of the suspension. Patent applicant Suzuki Motor Co., Ltd., Showa Seisakusho Co., Ltd.-1,- (and 2 others)

Claims (1)

[Claims] An inner cylinder is fitted with a predetermined gap inside an outer cylinder connected to an axle, an oil reserve chamber is defined inside the inner cylinder, a buffer pressure chamber is defined between both the inner and outer cylinders, and the above-mentioned Fit a piston inside the inner cylinder, connect the piston and the vehicle body with a piston rod,
The lower end of the coil spring is fixed to the outer peripheral surface of the outer cylinder, the upper end of the coil spring is fixed to the upper end of the piston rod, and a valve case is removably attached to the lower end of the outer cylinder. , at least three passages, first, second, and third, are formed in parallel in the valve case, 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 a relief valve is provided in the second passage that allows oil to flow from the oil reserve chamber to the buffer pressure chamber at a predetermined pressure or higher;
A check valve for blocking oil flow from the oil reserve chamber to the buffer pressure chamber is provided in the third passage, and a control hydraulic pressure port of the opening/closing valve is disposed below the valve case, and the control hydraulic pressure port An anti-dive suspension unit characterized by being configured to introduce brake operating pressure to.