JPH059547Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention is a front fork with a built-in damper that is interposed between the body of a motorcycle or other vehicle and serves as a shock absorber and fork to damp vibrations from the road surface. Regarding.

[Conventional technology]

As a conventional front fork of this type, one shown in FIG. 4, for example, has been developed.

This means that the inner tube 2 is inserted into and out of the outer tube 1, and the damper cylinder 3 stands up from the center of the lower part of the outer tube 1.
A piston rod is movably inserted into the damper cylinder 3 via a piston provided with a valve, and a valve mechanism V is provided at the lower part of the damper cylinder 3, making this a front fork with a built-in damper.

The valve mechanism V includes a pressure side valve 5 disposed around the outer periphery of a hollow support rod 4, and a needle valve 9, which is a variable throttle, provided in a passage 8 connecting a piston lower oil chamber 6 and a reservoir 7.

In other words, the pressure side valve 5 and the needle valve 9 constitute a valve mechanism provided in parallel in two passages connecting the piston lower oil chamber 6 and the reservoir 7,
Each valve generates a compression damping force.

[Problem that the invention attempts to solve]

According to the conventional front fork described above, since the pressure side valve 5 and the needle valve 9 which is a variable throttle are provided in parallel, the pressure side valve 5
Then, the damping force of the valve characteristic shown in graph a in FIG. 5 is obtained, and for the needle valve 9, graphs b, b',
Although a damping force is obtained based on the orifice characteristics shown by .

That is, since the damping force changes over the entire piston speed range by adjusting the needle valve 9, it is not possible to meet the demand for adjusting the damping force in the middle and high range while maintaining the damping force in the extremely low speed range. There is a problem.

Furthermore, since the needle valve 9, which is a variable throttle, is provided along the axial direction at the lower end of the front fork, there is a problem that it cannot be applied to a center axle type device in which the mounting bracket is provided at the lower end of the front fork.

Therefore, the purpose of this invention is to provide a front fork with a built-in damper that can adjust the damping force characteristics in the mid-high range while maintaining the damping force in the extremely low speed range, and can also be adapted to center axle type front forks. .

[Means for solving problems]

In order to achieve the above object, the structure of the present invention is to fit an outer tube and an inner tube so that they can be inserted and removed freely, a damper cylinder is raised from the center of the lower part of these fitting parts, and a piston with a valve is installed in the damper cylinder. In a front fork with a built-in damper, in which the piston rod is movably inserted through the damper cylinder, and a reservoir is defined on the outside of the damper cylinder, a check valve that opens when the damper cylinder is extended is provided at the bottom of the damper cylinder, and a check valve is provided at the bottom of the damper cylinder to check the connection between the piston's lower oil chamber and the reservoir. A bypass connecting the check valve is provided in parallel with the check valve, a variable throttle and a compression valve are provided in series in this bypass, the variable throttle is configured with a rotary valve that adjusts the opening area of the bypass, and the rotary valve is connected to the bypass. It is characterized by having a plurality of orifices with different diameters that are selectively opened and closed, and rotatably disposed on the side of the outer tube.

[Effect]

Since the variable throttle and the pressure side valve are placed in series in the middle of the passage that connects the piston lower oil chamber and the reservoir, the combined damping force characteristics of the two valves have almost no change in the extremely low speed range, and can be used in the mid to high range. Only the damping force can be adjusted.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 to 3.

An inner tube 2 is inserted into the outer tube 1 so as to be vertically removable, and a damper cylinder 3 and a hollow oil hole rod 10 are erected at the center of the lower part of the outer tube 1 via a hollow support rod 14 and a bolt 11. A piston rod 33 is movably inserted into the damper cylinder 3 via a piston 32 provided with a valve, and the piston 32 is inserted into the upper oil chamber 6.
a and a lower oil chamber 6b are partitioned into the damper cylinder 3.

The support rod 14 stands up inside the damper cylinder 3 and is pulled into the upper end of the base end 1a of the outer tube 1 by the bolt 11. At this time, the support rod 14
The locking step portion is the locking piece 3a of the damper cylinder 3.
The locking piece 3a of the damper cylinder 3 grips the base end 10a of the oil hole rod 10.

A disk 16 is attached to the outer periphery of the support rod 14 from below.
A check valve 17 and a valve holder 18 are inserted in series and tightened with a nut or caulking at the upper end.

An extension port 22 is formed in the disk 16,
A check valve 1 is installed at the upper end of the extension port 22.
7 is provided so that it can be opened and closed freely.

The lower part of the port 22 communicates with the reservoir 7 via a port 30 provided below the damper cylinder 3 and a passage 31 provided in the oil hole rod 10.

A valve body 4 is integrally assembled to the lower side of the outer tube 1.

A disk 9 is inserted into the valve body 4, and the disk 9 partitions two passages 5 and 6, one of which is the passage 2 provided in the outer tube 1.
8 into the reservoir 20, and the other passage 6 is connected to a passage 8 provided in the base end 1a of the outer tube 1, a passage 7 provided in the bolt 11, and the support rod 1.
It opens into the lower oil chamber 6b through a passage 21 provided in the lower oil chamber 6b.

Passage 21, Passage 7, Passage 8, Passage 6, Passage 5,
and passage 28 connects check valve 17 and port 2.
A parallel bypass is constructed for the two.

The disk 9 has one or more pressure side ports 19.
is formed to allow the two passages 5 and 6 to communicate with each other, and a leaf valve 27 as a pressure side valve is provided at the mouth end of the pressure side port 19 on the side of the passage 5 so as to be openable and closable. It is supported by a stepped portion of a support rod 23 passing through it.

A disc-shaped rotary valve 12 is rotatably abutted on the opening end of the pressure side port 19 on the side of the passage 6, and this rotary valve 12 engages with a locking piece 25 of a control rod 24 provided with a detent 15 and is rotated from the outside. Driven.

The rotary valve 12 is provided with a plurality of orifices a, b, c,..., n having different diameters along the circumferential direction, and by rotating the rotary valve 12, these orifices a, b, c,..., n are bored. Either one of them faces the pressure port 19.

As you can see from the above explanation, rotary valve 1
2 constitutes a variable throttle, which is provided in series with the pressure side valve 27.

During the extension operation, the inner tube 2 and the piston 32 rise, and the lower oil chamber 6 of the damper cylinder 3
b expands, and the oil corresponding to the withdrawal volume of the piston rod 33 is introduced from the reservoir 7, the passage 31, the port 30, and the extension port 22 into the lower oil chamber 6b by pushing open the check valve 17.

On the other hand, during compression operation, the piston 32 descends, and the oil corresponding to the amount of intrusion of the piston rod 33 flows into the passage 21, the passages 7, 8, 6, the port 19, the passage 5, and the piston rod 33.
28 and back to the reservoir 20.

At this time, a damping force with orifice characteristics is generated depending on the opening area of orifices a, b, c,..., n,
Next, the pressure side valve 27 is pushed open from the port 19 to generate a damping force characteristic of the valve.

As shown in FIG. 3, the pressure side valve 27
The characteristics due to the orifice a,
The characteristics due to the variable apertures b, c,...,n are shown by the graphs Q1, Q2, Q3,..., Qn depending on the amount of aperture, and the characteristics of the combination of the valves in series are shown by the graphs R1, R2, R3,... , Rn.

Therefore, as shown in the graphs R1, R2, R3, .

In the above embodiment, an upright type front fork with a built-in damper has been described, but the present invention can also be applied to a so-called inverted type front fork in which the outer tube is connected to the vehicle body side and the inner tube is connected to the wheel side.

[Effect of idea]

As described above, according to the present invention, since the compression side valve and the variable throttle are provided in series, it is possible to suppress changes in damping force in the extremely low speed range during compression operation, and to adjust the damping force in the medium and high speed range. I can handle it.

Furthermore, since the variable throttle rotary valve is disposed on the side of the outer tube, it can be adjusted without interfering with the bracket provided at the lower end of the front fork, and can be easily attached to the vehicle body.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway longitudinal sectional front view of a front fork according to an embodiment of the present invention, Fig. 2 is a side view of the rotary valve of Fig. 1, and Fig. 3 shows damping force characteristics according to the present invention. FIG. 4 is a partially cutaway longitudinal sectional front view of a conventional front fork, and FIG. 5 is a graph showing the conventional damping force. Explanation of symbols, 1... Outer tube, 2...
Inner tube, 3... damper cylinder,
5, 6, 7, 8, 28...Aisle, 6a, 6b...
Oil chamber, 17...Check valve, 12...Variable throttle rotary valve, 20...Reservoir, 27
...Pressure side valve, 32...Piston, 33...Piston rod.

Claims (1)

[Scope of utility model registration request] The outer tube and the inner tube are fitted so that they can be inserted and removed, a damper cylinder is raised from the center of the lower part of these fitting parts, and a piston rod is movably inserted into the damper cylinder via a piston provided with a valve. In a front fork with a built-in damper, in which a reservoir is partitioned on the outside of the damper cylinder, a check valve that opens when the damper cylinder is extended is provided at the bottom of the damper cylinder, and a bypass is provided in parallel with the check valve to connect the oil chamber at the bottom of the piston and the reservoir. A variable throttle and a compression valve are provided in series in the bypass, and the variable throttle is composed of a rotary valve that adjusts the opening area of the bypass, and the rotary valve has a plurality of orifices with different diameters that are selectively opened and closed in the bypass. A front fork with a built-in damper is equipped with a damper and is rotatably arranged on the side of the outer tube.