JPH0418953Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention is applicable to motorcycles or three-wheeled motorcycles with a single front wheel (hereinafter referred to as motorcycles, etc.).
The present invention relates to a front fork, and particularly to a front fork equipped with a gas chamber partitioned into two upper and lower chambers by a partition wall with an on-off valve provided at the upper part.

[Conventional technology]

2. Description of the Related Art Suspension systems for motorcycles and the like generally use a hydraulic shock absorber consisting of a shock absorbing spring and a hydraulic damper.

On the other hand, in vehicles such as motorcycles, the loads borne by the front and rear wheels change due to inertia caused by acceleration and deceleration during driving. In particular, if sudden braking is applied while the vehicle is running, the rider's weight is applied to the steering wheel due to inertia, causing the steering wheel to sink into the steering wheel significantly, impairing maneuverability.

A front fork that solves these problems is disclosed, for example, in Japanese Utility Model Application Publication No. 57-37692.

This is a tank equipped with a valve device at the upper open end of a fork pipe. In other words, a main gas chamber is formed in the upper part of the fork pipe, and a tank equipped with an auxiliary gas chamber communicating with the main gas chamber and a plate valve for opening and closing communication between both chambers is fixed to the upper end of the fork pipe. It is something. Further, the plate valve is normally biased in the opening direction by a spring, and is connected to the brake lever via a wire.

[The problem that the idea attempts to solve]

However, in this structure, a tank equipped with a valve device is installed above the fork pipe, separate from the fork pipe.
There is a problem in that the part becomes large and the installation of instruments and handles is restricted. Furthermore, since the plate valve, which is biased in the opening direction by a spring, is closed by operating the brake lever, there is an operational problem in that the operating force of the control lever becomes large.
Furthermore, since the desired gas spring characteristics are determined by the combined volume of the main gas chamber and the auxiliary gas chamber, assuming that the auxiliary gas chamber, that is, the tank, is constant,
It is difficult to obtain a product with the desired nose dive prevention properties. That is, there is a cost problem in that tanks with auxiliary gas chambers of different volumes must be prepared for different models with different fork pipe diameters, strokes, shock spring characteristics, etc.

This idea was made to solve these problems.It is compact, does not require a particularly large operating force, and can achieve the desired nose dive prevention characteristics by simply changing the setting position of the partition wall in the upper cylinder. It offers a choice of front forks.

[Means to solve the problem]

In order to achieve such an object, the present invention provides a front fork of a motorcycle, etc., in which a gas chamber is partitioned into two upper and lower chambers by a partition wall, and a valve opening opened and closed by a valve body is provided in the partition wall. Two upper and lower chambers are formed in the upper cylinder, a solenoid for driving the valve body is built in the upper end of the upper cylinder, the valve body is located on the lower chamber side, and the valve body and the plunger of the solenoid are connected. This is achieved by connecting the two valves with a connecting rod that passes through the valve port.

[Effect]

Both the upper and lower chambers constituting the gas spring chamber are formed within a single cylinder, and all the constituent members of the valve device are also housed within the cylinder.

〔Example〕

In FIG. 1, the reference numeral 1 indicates a steering shaft tube, which is provided at the front end of the vehicle body 2. As shown in FIG. 3 is the front wheel,
Reference numeral 4 denotes a front fork, which is provided parallel to both sides of the front wheel 3 (one side is not shown), and has an axle 5 supported at its lower end.
The front wheel 3 is supported through the front wheel 3. Further, the front fork 4 has an upper bracket 6 at its upper part.
and are connected to each other via the lower bracket 7,
The front wheels 3 are steered within the steering tube 1 around a steering shaft (not shown) connecting the upper and lower brackets 6 and 7. As shown in FIG.

FIG. 2 is a sectional view schematically showing the structure of the front fork 4, in which 11 is a lower cylinder body;
2 is an upper cylindrical body, and both cylindrical bodies 11 and 12 are telescopically combined so as to be expandable and retractable. The front fork 4 is filled with hydraulic oil up to the position indicated by 0 in the figure, and the volume of the gas chamber is determined by this liquid level position. A cylinder is erected at the bottom of the lower cylinder 11, and a piston 14 provided at the lower end of the upper cylinder 11 is fitted between the outer periphery of this cylinder and the inner periphery of the lower cylinder 11. It matches. This piston 14 is provided with a check valve (not shown) that is opened when the front fork 4 is compressed and closed when it is extended. Therefore, when the check valve is open, almost no damping force is generated, but when the check valve is closed, the hydraulic oil passes only through the predetermined throttle, so a damping force is applied. Reference numeral 15 indicates a compression coil spring which functions as a buffer spring together with a gas chamber which will be described later.

Inside the upper cylinder 12 above the liquid level 0,
A gas chamber G is formed. In this embodiment, the gas chamber G communicates through a communication port 16 with an internal pressure adjusting device (not shown) that can appropriately adjust the internal pressure of the gas chamber G.

Therefore, in this front fork 4, the compression coil spring 15 and the gas spring caused by the internal pressure of the gas chamber G function as a buffer spring.

In FIG. 3, a gas chamber G provided above the liquid level 0 is partitioned into an upper chamber G ₁ and a lower chamber G ₂ by a partition wall 21 provided in the middle thereof.

The partition wall 21 is fixedly held by a cylindrical body, and a valve port 22 is provided in the center of the partition wall 21 to communicate the upper and lower chambers G _{1 and} 2, and a valve body 2 is provided on the lower chamber G ₂ side of this valve port 22.
3 is positioned so that it can be opened and closed freely. This valve body 2
3 is connected to a plunger 28 of a solenoid 25 via a connecting rod 24 passing through the valve port 22, and these are weakly urged downward by compression springs 26 and 27 to open the valve port 22. There is. Therefore, in this state, the gas chamber volume is both the upper and lower chambers G _1,2
The gas spring has the characteristics of the sum of the volumes of . In addition, 29 is an aperture, and 31 is an electric wire for energizing to drive the solenoid 25.

Now, for example, when you operate the brake lever on a motorcycle to apply the brakes, the electric wire 31 connects from the brake lamp circuit.
When an operation command current is applied to the solenoid 25 through the valve, the plunger 28 is immediately attracted upward and closes the valve port 22. Therefore, since the lower chamber _G2 is the only gas chamber that acts as a gas spring at this time, the internal pressure of the gas chamber due to the compression operation of the front fork 4 increases rapidly.

Note that when the valve body 23 closes the valve port 22 due to the operation of the solenoid 25, the internal pressure in the lower chamber _G2 increases to the upper chamber _G1.
The difference in internal pressure between the two chambers G1 _{and G2} causes the valve element 23 to be pressed toward the valve port 22 and self-retained. That is, solenoid 25 is used to close the valve.
There is no need to keep energizing. And aperture 29
By connecting both the upper and lower chambers _G1,2 ,
After a predetermined period of time, the pressure becomes equal and the pressure is restored by the biasing force of the spring 27.

In the front fork of the embodiment described above,
Although a separate internal pressure adjustment device for the gas chamber G is provided, a predetermined amount of gas may be hermetically sealed in the gas chamber G in advance.

Additionally, the two front forks on both sides of the front wheels can be individually controlled on each side using a microcomputer, making it possible to provide the front wheel suspension with spring characteristics more suited to the vehicle's driving conditions. It is possible.

[Effect of idea]

As explained above, according to this invention, the two upper and lower chambers that form the gas chamber are both formed in the upper cylinder, and the solenoid that drives the valve element that opens and closes the two chambers is built into the upper end of the upper cylinder. However, since the valve body is located on the lower chamber side and the valve body and the plunger of the solenoid are connected by a connecting rod passing through the valve port, all the members are inside the upper cylinder. It can be miniaturized without requiring any special members to form a tank. Therefore, there are no restrictions on mounting instruments or handlebars located near the upper part of the front fork. Further, since there is no need to pull the wire against the biasing force of the valve return spring as in the prior art, there is no effect on the operation of the brake lever, and there is no need to route the wire. Furthermore, simply by changing the position of the partition wall in the upper cylinder and the amount of hydraulic oil, the volume of the entire gas chamber and the volume of each upper and lower chamber can be freely changed, making it possible to adapt to many models with different spring characteristics. There are also advantages.

[Brief explanation of drawings]

The drawings show an embodiment of this invention, in which Fig. 1 is a side view showing the front part of a motorcycle, Fig. 2 is a schematic cross-sectional view showing the entire front fork, and Fig. 3 is a section of the part shown in Fig. 2. It is an enlarged view. 4...Front fork, 11...Lower cylinder body,
12... Upper cylinder body, 21... Partition wall, 22... Valve port, 23... Valve body, 24... Connection rod, 25... Solenoid, 28... Plunger, G... Gas chamber,
G ₁ ... upper chamber, G ₂ ... lower chamber.

Claims (1)

[Scope of utility model registration request] It is equipped with an upper cylinder body and a lower cylinder body in which one cylinder body is slidably inserted into the other cylinder body, and the gas chamber is divided into two upper and lower chambers by a partition wall, and the gas chamber is opened and closed by a valve body in this partition wall. In a front fork of a motorcycle or the like provided with a valve port, the two upper and lower chambers are formed in the upper cylinder, a solenoid for driving the valve body is built in the upper end of the upper cylinder, and the valve body is connected to the lower chamber. A front fork for a motorcycle, etc., characterized in that the valve body and the plunger of a solenoid are connected to each other by a connecting rod passing through the valve port.