JPS61235286A - Sinking preventive device for front fork - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an improvement in a device for preventing a front fork from sinking during braking in a motorcycle or the like.

(Prior Art) In a motorcycle, when braking, the center of gravity shifts due to inertia, which increases the share of the backrest on the front fork, causing the front fork to sink.

Therefore, various devices (anti-nose grip devices) have been proposed that prevent sinking by sensing the braking action and increasing the compression side damping force of the front fork (Utility Model Application No. 57-20385). (see publication).

Among these, the one shown in FIG. 13 has been proposed by the present applicant as Utility Application No. 101685/1985.

A damping force adjusting device 2 is attached to a 7 outer tube 1 having a capacity of 7 cF and 7 tons, and a damping valve 4 is interposed in a flow path 3 through which hydraulic oil flows during pressure operation.

This damping valve 4 has a valve plate 6 interposed on a spool 5 via a relief spring 7, and this valve plate 6 is seated on a valve seat 8 interposed in the flow path 3.

Solenoid 9 moves armature 10 against spring 11. The spool 5 is seated on this armature 10 via a spring 21.

The solenoid 6 is energized during braking by a signal from a brake switch (not shown), and the spool 5 works in conjunction with the armature 10 to seat the valve plate 6 on the valve seat 8 to cut off the flow of pressure side hydraulic oil and prevent the front fork from sinking. suppress.

The spool 5 is formed with a pressure guiding hole 20 penetrating in the ring direction,
Since the pressure in the oil reservoir chamber is guided to both ends, it operates reliably without being affected by pressure fluctuations in the oil reservoir chamber.

(Problem to be solved by the invention) However, since the energization of the solenoid 9 is controlled ON/OFF, during braking with a weak braking force, the contraction of the front 7 is suppressed more than necessary, and the braking When the vehicle is pushed up from the road, it is unable to absorb and cushion the impact, which can lead to a worsening of ride comfort.

In other words, it is necessary to ensure a certain degree of shock absorption ability during gentle braking in which there is little sinking of fluorocarbons.

The present invention aims to solve the above problems.

(Means for Solving the Problems) The present invention forms a boat portion in a valve seat interposed in a passage through which hydraulic oil flows during pressure side operation of a 70-ton, 7-year-old one;
A spool valve is provided in this boat portion to be inserted with a predetermined amount of wrap.

The boules pulp is slidably fitted into the spool driven by the Tsuremade, and a relief spring is interposed to bias the spool valve in the closing direction.

The above spool has a pressure-receiving surface equivalent to that of the spool valve, and a pressure guiding hole is formed that penetrates in the annular direction, so that thrust is generated in any direction of the spool due to fluctuations in the internal pressure of the spool. Try not to.

A means for detecting the braking force of the two-wheeled vehicle is provided, and a solenoid is energized based on this detection signal to adjust the amount of lap according to the braking force.

(Function) By adjusting the wrap amount of the spool valve, the amount of compression of the outer relief spring changes when the spool valve opens, so it can be used without changing the initial compression amount of the relief spring. The opening pressure of the spool valve can be adjusted without being affected by the internal pressure of the solenoid, and therefore the solenoid can stably control the damping force in accordance with the braking force without increasing the required driving force.

(Embodiment) FIG. 1 shows a first embodiment of the present invention, in which the damping valve 4 has a boat portion 31 formed on the valve seat 28 interposed in the flow path 3;
A spool valve 26 into which the land portion 30 is inserted with a wrap amount δ is provided in the boat portion 31.

This spool valve 26 is slidably fitted onto the spool 5, and a relief spring 7 is interposed therebetween which urges the spool valve 26 to come into contact with the stepped portion Sa.

The diameter of the land portion 30 is set to be approximately the same as the diameter of the contact surface with the seal 13 of the spool valve 5.
The areas of the pressure receiving surface 26A of the spool 6 and the pressure receiving surface 5A of the spool 5 are made equal. This balances the spool 5 so that no thrust is generated in either direction based on the internal pressure of the front fork.

Further, the spool 5 is formed with a pressure guide hole 20 penetrating in the ring direction to guide the pressure of the oil reservoir chamber to both ends of the spool 5, thereby balancing the pressure at both ends of the spool 5.

A proportional solenoid 29 is provided to excite and drive the armature 10 against the spring 11, and the base end of the spool 5 is seated on the armature 10 via the spring 21.

and a sensor that detects the opening degree of the brake lever,
Alternatively, a means for detecting the braking force of the two-wheeled vehicle, such as a sensor for detecting the pressure of the brake hydraulic circuit, is provided, and the drive current of the solenoid 29 is proportionally controlled in accordance with the braking force based on this detection signal.

With this structure, the same reference numerals are given to the same components as those of the conventional example, and the operation thereof will be explained next.

During normal driving when the solenoid 29 is de-energized, the spool valve 26 is held at a fully open position away from the valve seat 28, and the front fork absorbs vibrations to maintain a soft riding comfort.

On the other hand, during braking, the solenoid 29 pulls the spool valve 26 into the boat portion 31 of the valve seat 28 according to the amount of energization, cuts off the flow of pressure side hydraulic oil, and suppresses sinking of the front fork.

At this time, the excitation force of the solenoid 29 that controls the amount of displacement of the spool valve 26 changes according to the braking force, and the amount of overlap δ between the land portion 30 and the boat portion 31 is adjusted.

While the spool valve 26 is blocking the flow of pressure hydraulic oil, when the wheel is pushed up due to unevenness on the road surface, the internal pressure of the front fork increases, and the spool valve 26 compresses the relief spring 7. At the same time, the land portion 30 is pulled out from the port portion 31, the flow path 3 is opened, and the pressure side hydraulic oil is relieved.

In this case, the opening pressure P of the spool valve 26 is calculated as follows: where Xo is the initial deflection of the relief spring 7, 1 is the spring constant, and S is the area of the pressure receiving surface 26A of the spool valve 26, p=(x, +δ)K/ It is expressed as S and is linearly proportional to the wrap amount δ.

Therefore, during sudden braking when the internal pressure increases significantly, the solenoid excitation force is strengthened and the wrap amount δ is increased to exert a high damping force, and during gentle braking, the wrap amount δ is decreased to weaken the damping force. When the vehicle receives a bump from the road surface during gentle braking, the spool valve 26 opens relatively quickly and absorbs the impact.

Note that when increasing the opening pressure of the spool valve 26, the IJ
-7 Since the initial compression amount of the spring 7 is not changed by the solenoid 29, the required driving force of the solenoid 29 can be small.

The internal pressure of the front fork is balanced by acting on both the pressure receiving surface 26A of the spool valve 26 and the pressure receiving surface 5A of the spool 5, and the pressure in the oil reservoir chamber is led to both ends of the spool 5 through the pressure guiding hole 20. Therefore, the opening pressure of the spool valve 26 is not affected by these pressure fluctuations, and depends only on the excitation force of the solenoid 29 and the urging force of the spring 11, and is at a position where these are balanced. The amount of wrap of the spool valve 26 is maintained correctly.

Next, the embodiment shown in FIG. 2 will be explained. In this case, the spool 5 and the armature 10 are integrally formed. In this case, the armature 10 and the spool 5 move as one, so the spring 21 is unnecessary. becomes.

(Effects of the Invention) As described above, the present invention provides a spool valve that is inserted with a predetermined amount of overlap into a port formed in a flow path that guides pressure side hydraulic oil, and a spool valve that is attached to a spool that is driven by a proportional type In addition to ensuring a pressure-receiving surface area equivalent to that of the
Since the wrap amount of the spool valve is adjusted according to the braking force using a solenoid, the compression side fecal sterilization force can be controlled to increase or decrease according to the braking force.
It ensures excellent shock absorption ability and provides a stable ride. In addition, when adjusting the damping force, the initial compression amount of the relief spring is not changed and the front fork's internal pressure is not affected, so the required driving force of the solenoid does not become large and the damping force can be set accurately. There is an effect.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the @1 embodiment of the present invention, FIG. 2 is a sectional view of the second embodiment, and FIG. 3 is a sectional view of the conventional example. DESCRIPTION OF SYMBOLS 1... Outer tube, 3... Flow path, 4... Damping valve, 5... Spool, 5A... Pressure receiving surface, 7...
Relief spring, 11... Spring, 20...
- Pressure guiding hole, 26... Spool valve, 26A... Pressure receiving surface, 28... Valve seat, 29... Solenoid, 30...
...Land Department, 31-...Boat Department Patent Applicant Kayaba Kogyo Co., Ltd. Figure 1

Claims (1)

[Claims] A boat part is formed on the valve seat that is inserted into the flow path through which hydraulic oil flows when the front fork is operated on the pressure side, and a spool valve that is inserted into the boat part so as to be able to overlap is provided, and this spool valve is connected to a relief spring. A proportional solenoid is provided, which is slidably fitted onto the spool via the spool valve, and which proportionally displaces the spool in accordance with the excitation force.
A front fork sinking prevention device, characterized in that the solenoid is excited in accordance with braking force.