JPS6257551B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a front fork that suspends a front wheel of a two-wheeled vehicle or the like, and particularly to a front fork whose damping force automatically increases as the inertial force of the front fork increases.

In the conventional so-called telescopic type front fork, an oil hole is drilled on the outer periphery of the seat pipe.
Oil in the oil chamber whose volume decreases as the front fork expands and contracts flows out through the oil hole, and at this time, oil flow resistance acts as a so-called damping force. Therefore, the faster the inner cylinder penetrates into the outer cylinder, the greater the resistance, thereby preventing the bottoming out phenomenon between the inner cylinder and the outer cylinder. However, this type of means is not necessarily effective when the downward inertial force exerted on the inner cylinder becomes extremely large, such as during braking, and therefore various improvements are needed in terms of handling stability and shock absorption during braking. It was hot.

As a means to solve the above problem, there is a so-called front fork with an anti-nose dive device, which has an oil passage connecting the oil chambers inside and outside the seat pipe on the side of the outer cylinder, and is equipped with a device that closes the oil passage during braking. This type of device is an effective means of solving the above problems, and has been put into practical use in many car models in recent years, but it has become complicated and requires further improvement in terms of cost, weight, assembly man-hours, etc. It has been demanded.

The present invention solves the problems of the conventional device by providing an inertia valve that slides in response to inertia force on the outer periphery of the oil lock collar. The oil passage area connecting the oil chambers is automatically adjusted. An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a longitudinal sectional view of the main parts of a front fork according to an embodiment of the present invention, in which the lower part of an inner cylinder 1 whose upper end is attached to the handlebar of a motorcycle is slidably fitted inside an outer cylinder 2. The upper end of the seat pipe 3 installed on the bottom surface of the outer cylinder 2 is slidably fitted inside the inner cylinder 1, and the vehicle body suspension spring 4 is inserted between the upper end of the seat pipe 3 and the upper part of the inner cylinder 1. It's hung up. The outer cylinder 2 is filled with oil and the shaft of the front wheel is fitted into the mounting hole 5 at the lower end, and an oil seal 6 is provided at the upper end. Also, a check valve 7 is provided at the lower end of the inner cylinder 1, an oil hole 8 is formed in the upper part of the seat pipe 3, and an oil lock piece 1 is fitted with an O-ring 9.
0 into the lower end of the pipe 3, and the oil holes 11 and 12 into the lower part of the pipe 3 and the oil lock piece 10.
An annular check valve 14 is provided at the upper end of the oil lock piece 10 and is pressed by a disc spring 13. Furthermore, an oil passage 15 is provided on the outer periphery of the outer cylinder 2 to connect the oil chamber A in the outer cylinder and the oil chamber B in the seat pipe,
Its upper end is connected to the outside of the seat pipe 3 via oil holes 16 and 17, which will be described later, and its lower end is connected to the outside of the sheet pipe 3 through oil holes 16 and 17, which will be described later.
1 to the inside of the sheet pipe 3. On the other hand, a concave groove 18a is provided on the outer periphery of the oil lock collar 18 fitted to the inner lower end of the inner cylinder 1,
The oil holes 16 and 17 are provided in the inner cylinder 1 and the oil lock collar 18 through the groove 18a, and a cylindrical inertia valve 20 pressed by a valve ring 19 is slid into the groove 18a. Usually, this inertia valve 20 is provided with a spring 19.
This allows the oil holes 16 and 17 to communicate with each other, and when the inner cylinder 1 sinks at a speed exceeding a certain level, its current position is maintained by inertia force. Therefore, the spring 19 is compressed by the inertial force, and the area of the oil hole 17 is reduced. Note that 21 is a button.

Next, its operation will be explained.

First, in the compression process, oil in the oil chamber A in the outer cylinder flows into the gap between the inner cylinder 1 and the outer cylinder 2 through the oil hole 17 of the oil lock collar 18 and the oil hole 16 in the inner cylinder 1, and then continues to flow. Oil passage 15, oil lock piece 10
The oil flows into the oil chamber B in the seat pipe 3 through the oil hole 12 in the seat pipe 3 and the oil hole 11 in the seat pipe 3. Then, while driving, for example, when braking is applied and the inner cylinder 1 sinks and the inertial force becomes larger than a certain value, the inertia valve 20 becomes in the same state as if it compressed the valve spring 19 and moved upward, reducing the area of the oil hole 17. Therefore, it is possible to increase the damping force and prevent the inner cylinder 1 from sinking. Note that in the compression process, the check valve 7 of the inner cylinder 1 opens and the oil chamber C above the check valve 7 is replenished with oil, as is conventional. Moreover, the movement of the outer cylinder 2 is not hindered because the inertia valve 20 does not operate in response to impacts received from the road surface due to unevenness on the ground.

On the other hand, in the extension process, the volume of the oil chamber c decreases, and oil flows into the seat pipe 3 through the oil hole 8 of the seat pipe 13. Further, the oil chamber A is refilled with oil by opening the check valve 14 of the oil lock piece 10.

In this way, the present invention uses an inertia valve to prevent the inner cylinder from sinking during braking by utilizing inertia force.
The so-called nose dive can be controlled, and even if the outer cylinder is pushed up, the inertia valve does not operate, so its operation is not hindered. Furthermore, the configuration is much simpler than the conventional on/off type that detects braking torque and shuts off the flow.

FIG. 2 is a sectional view of a main part showing another embodiment of the present invention, which is a further improvement of the previous embodiment.
As shown in the figure, the seat pipe 3 in FIG.
An oil hole 22 communicating with the oil chamber A and the oil passage 15 is provided in the flange portion of the oil lock piece 10 fitted to the outer periphery of the base of the oil lock piece 10. A check valve 24 is provided which closes and opens against a spring 23 in response to the pressure in the oil chamber A in the outer cylinder.

When the check valve 24 is provided in this way, the inertia valve 2
When the pressure in the oil chamber A increases due to impact on the cropping wheel during operation, the check valve 24 of the oil lock piece 10 opens, providing a buffering effect.

As explained above with respect to the embodiments, the front fork of the present invention not only prevents the steering wheel from sinking when braking is applied, but also has an effective buffering effect against the impact received from the road surface during operation if necessary. In addition, the simple configuration makes manufacturing and assembly easy.In particular, the front fork has good performance and high maneuverability, allowing it to follow road conditions without the need for a braking/locking function. is obtained.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a main part showing one embodiment of a front fork of the present invention, and FIG. 2 is a longitudinal cross-sectional view of a main part showing another embodiment. 1...Inner cylinder, 2...Outer cylinder, 3...Seat pipe, 4...
Vehicle suspension spring, 7... Check valve, 8... Oil hole, 10... Oil lock piece, 11, 12... Oil hole, 13... Belleville spring, 14... Check valve, 15... Oil passage, 16, 17
...oil hole, 18...oil lock collar, 18a...concave groove, 19...valve spring, 20...inertia valve, 22...oil hole, 23...spring, 24...check valve.

Claims (1)

[Scope of Claims] 1. In a front fork of a motorcycle, etc., in which an inner cylinder and an outer cylinder are slidably fitted and a seat pipe is installed at the bottom of the outer cylinder, an oil chamber in the outer cylinder and a seat pipe are provided on the outer periphery of the outer cylinder. An oil passage connecting the inner oil chamber is provided, and an oil hole is provided in the inner cylinder and the oil lock collar fitted in the inner cylinder, and a groove is provided on the outer periphery of the oil lock collar. A front fork for a two-wheeled vehicle or the like, characterized in that a cylindrical inertia valve that is slidable when pressed by a valve spring is disposed therein, and that the inertia valve can freely open and close an oil hole in the oil lock collar. 2. In a front fork of a motorcycle, etc., in which the inner cylinder and the outer cylinder are slidably fitted and a seat pipe is installed at the bottom of the outer cylinder, the oil chamber in the outer cylinder and the oil chamber in the seat pipe are connected to the outer periphery of the outer cylinder. An oil passage is provided, and an oil hole is formed in the inner cylinder and the oil lock collar fitted in the inner cylinder, and a groove is provided on the outer periphery of the oil lock collar, and a valve spring is pressed into the groove. A cylindrical inertia valve that can freely slide is provided, and the inertia valve can freely open and close the oil hole of the oil lock collar, and connects an oil path to the flange of the oil lock piece fitted to the outer periphery of the base of the seat pipe. A front fork for a two-wheeled vehicle or the like, characterized in that a check valve is provided below the oil passage and opens in response to pressure in an oil chamber in an outer cylinder.