JPH0257493A - Damping force adjustable front fork - Google Patents

Abstract

PURPOSE:To smoothen the varying characteristic of the damping force in an arrangement where a passage leading to an oil chamber inside the damper is in communication with an oil sump via a damping valve, by furnishing a parallel circuit of a relief valve and a throttle in series with the damping valve. CONSTITUTION:Within an inner tube 2 to be inserted in an outer tube, a subjected front fork is equipped with a damper in the lower part of a piston rod 6 coupled with the above-mentioned inner tube 2. In the upper part of this inner tube 2, a damping valve 12 is furnished which is attracted and closed with energization of a solenoid 11, and a passage 25 in communication to an oil chamber inside the damper is put in communication with an oil sump 9 in the upper part of the damper via this damping valve 12. On this case, on the understream side, the damping valve 12, a relief valve 50 and a throttle 51 are furnished parallelly. The relief valve 50 shall close a valve mouth 55 by pressure contacting a ring-shaped valve 53 with a valve body 52 with the aid of a spring 54, and the throttle 51 is constituted from a gap passage 56 between the body 52 and the piston rod 6.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a front 7 for a two-wheeled vehicle with a large adjustment range of damping force.
Regarding Saiichiri.

(Prior technology) Front 7 for motorcycles with electromagnetically adjustable damping force
Patent application No. 63-18994 by the applicant as Oak
No. etc. have been proposed.

This is constructed as shown in FIG.

An inner tube 2 is slidably inserted into the outer tube 1, and a damper 3 is housed inside these tubes. In this damper 3, a piston 5 attached to a piston rod 6 connected to an inner tube 2 is slidably housed in a sill 4, and this sill 4 acts as an actuator.
It is erected at the bottom of the tube 1.

The inside of the damper 3 includes a lower oil chamber 7 that contracts when the pressure side is activated,
An upper oil chamber 8 that contracts during expansion-side operation is defined via the piston 5. The piston 5 is provided with a main pulp (check pulp) 5A that opens only during pressure side operation and allows hydraulic oil to flow from the lower oil chamber 7 to the upper oil chamber 8.

An oil reservoir chamber 9 is formed above the damper 3 and located inside the inner tube 2, and this oil reservoir chamber 9 is connected to a base valve (not shown) disposed at the bottom of the cylinder 4 from an annular passage 10 outside the cylinder 4. It communicates with the lower oil chamber 7 via. The base valve applies resistance to the hydraulic oil flowing out from the lower oil chamber 7 to the annular passage 10 when operating on the compression side to generate a damping force, but when operating on the rebound side, it allows the hydraulic oil to pass in the opposite direction without resistance. It has become.

A solenoid 11 is attached to the upper end of the inner tube 2, and a valve case 13 is installed coaxially with the solenoid 11.
A damping valve 12 housed in the damping valve 12 is disposed, and the piston rod 6 passes through the center thereof.

A suspension spring 14 is disposed between the lower surface of the valve case 13 and the upper surface of the damper 3 via spring seats 14A and 14B.

The valve case 13 also serves as an inner tube cap, and is formed in a cylindrical shape and is screwed onto the inner circumference of the inner tube 2 via a threaded portion 15, and a solenoid 11 and a damping valve 12 are housed inside the valve case 13. has been done.

A bobbin 17 made of a non-magnetic material is attached to the piston rod 6 passing through the center of the thread/id 11, and a coil 16 is wound around the bobbin 17. As will be described later, inside the hollow piston loft 6,
A core 18 of magnetic material is inserted and fixed inside the coil 16.

In the damping valve 12, a disk-shaped valve 21 made of a magnetic material is arranged so as to be able to move toward and away from a valve seat 20 having a boat 22 fixed to the outer periphery of the piston rod 6. The valve seat 20 has an inner peripheral part 20A formed of a magnetic material, and an outer peripheral part 20 having a boat 22 that is closed by the valve 21.
B is made of a non-magnetic material.

Further, the valve case 13 into which the outer periphery of the valve seat 20 is fitted is formed of a magnetic material, and when the solenoid 11 described in 1ifJ is energized, the piston rod made of magnetic material passes through the inner peripheral portion 2OA, the valve 21, and the valve case 13. By configuring a closed circuit magnetic path, the valve 21 is attracted to the valve seat 20 according to the solenoid excitation current value.

In order to regulate the amount of movement of the valve 21, a stopper 23 fixed to the piston rod 6 is made of a non-magnetic material, and a leaf spring 24, one end of which is engaged with this stopper 23, also closes the valve 21. Forced in the direction of the valve.

A passage 25 is formed passing through the interior of the piston rod 6, and this passage 25 opens to the upper oil chamber 8 via a passage 26. Further, the passage 25 communicates with a valve chamber 27 defined below the solenoid 11 via a port 28 . The valve chamber 27 communicates with the oil reservoir chamber 9 via the boat 22.

The upper end of the piston rod 6 is fixed to the upper end of the thread/id 11 fixed inside the valve case 13 with a nut 31 via a washer 30.

A seal ring 33 provides a seal between the valve case 13 and the inner tube 2, and a seal ring 34 provides a seal between the inner periphery of the valve case 13 and the outer periphery of the solenoid 11.
Accordingly, the inner periphery of the thread/id 11 and the piston rod 6 are further sealed by seal rings 35, respectively.

A lead wire 40 connected to the coil 16 is taken out from the side of the upper end of the solenoid 11 that is open to the weather. The lead M40 passes through a camp 41 fitted into the upper part of the valve case 3, and is connected to an external control circuit (not shown). The control circuit is used to adjust the damping force according to driving conditions, such as when braking or when driving at high speed.
When cornering or the like, an exciting current is supplied to the solenoid 11 to increase the generated damping force.

Therefore, for example, when the front 7 oak operates on the expansion side, the hydraulic oil in the upper oil chamber 8 inside the guava 3 contracts,
Since the main valve 5A is closed, oil flows from the passage 25 of the piston rod 6 to the oil reservoir chamber 9 through the drain valve 12. In this case, when the solenoid 11 is not energized, the damping valve 12 generates a damping force in accordance with the leaf spring 24.

Note that hydraulic oil is sucked into the expanding lower oil chamber 7 from the annular passage 10 without resistance via a base valve (not shown).

On the other hand, when the solenoid 1 is energized, the coil 16 is excited, and the excitation force attracts the pulp 21 to the valve seat 20, increasing the closing force of the damping valve 12. Therefore, in this state, the resistance to the hydraulic oil from the passage 25 increases, resulting in a large damping force.

occurs. This damping force changes depending on the excitation current value for the solenoid 11, and the damping force increases as the excitation force increases.

On the other hand, when the front 7-year-old only operates on the pressure side, part of the hydraulic oil in the lower oil chamber 7 that contracts flows from the annular passage 10 to the oil reservoir chamber 9 through the base pulp (not shown), and
The remainder flows from the main pulp 5A into the expanding upper oil chamber 8. In this case, when the passage resistance through the passage 25 of the piston rod 6 and the damping valve 12 is smaller than the pressure side resistance in the base pulp, a flow to the oil reservoir chamber 9 also occurs through this passage. When the solenoid 11 is not excited, the pressure side flow is divided into both directions, so the generated damping force can be kept relatively small.

On the other hand, when the solenoid 11 is excited and the closing force of the damping valve 12 increases, the generated damping force increases correspondingly.

However, if the pressure generated in the base pulp becomes larger than the closing force of the damping valve 12, the damping valve 12 will open, so at that time,
The increasing characteristic of the damping force slows down from α.

Therefore, the compression-side capital reduction force is relatively small compared to the rebound-side damping force.

(Problem to be Solved by the Invention) By the way, when we examine in detail the damping force generated when the solenoid 11 is energized, as shown in FIG. It can be seen that it depends on the composite spring force of the suction force and the spring force of the leaf spring 24. The suction force by the solenoid 11 becomes smaller as the valve lift amount increases, whereas the spring force of the leaf spring 24 increases in proportion to the lift. For this reason, as the resultant spring force increases, it exhibits a characteristic that it once decreases and then increases again.

In reality, as shown in Figure tJIJ4, there is a leakage of hydraulic oil, so the characteristics obtained by combining this leakage characteristic (approximate to the orifice characteristic) and the damping force characteristic due to the damping valve 12 are as shown in Figure 5. .

What is shown as conventional characteristic B in this figure is the damping force characteristic that actually occurs, but as the excitation speed increases, the generated damping force reaches its peak value at the initial stage and generates a sarno.
[From 8 onwards, the damping force decreases once and then increases again.

The relationship between the damping force and the excitation displacement of the front 7 oak is shown in FIG. 6, and the area surrounded by this characteristic waveform represents the absorbed energy in one cycle of the front 7 oak.

However, in the waveform of the conventional structure, there is a region in which the relationship between displacement and damping force changes suddenly, and this prevents a smooth connection of damping force changes and causes a decrease in ride comfort.

It is an object of the present invention to solve these problems, to smooth the change characteristics of the damping force with respect to the displacement of the fluorocarbon, and to increase the degree of freedom in adjusting and setting the damping force.

(Means for Solving the Problems) Therefore, the present invention has an inner tube housed in an outer tube, a damper built in inside these tubes, and a piston rod penetrating volume of the damper inside the inner tube. The oil chamber inside the damper is formed by penetrating the piston rod of the damper, defining an oil reservoir chamber that compensates for the inflow and outflow of hydraulic oil, and providing a damping valve that is attracted and closed by the excitation of a solenoid at the top of the inner tube. In the front 7 hole, which has a passage communicating with the oil reservoir chamber via the damping valve, a parallel circuit of the I-no 7 pulp and the throttle is inserted in series with the damping valve.

(Function) As the front 7 oak expands and contracts, the hydraulic oil inside the damper passes through the passage of the piston rod, passes through the damping valve, is divided into the relief pulp and the throttle, and is returned to the oil sump chamber.

In areas where the flow rate is relatively low, the reduction in damping force caused by the damping valve is compensated for by the resistance between the relief pulp and the throttle, and for this reason, the synthetic damping force characteristic does not temporarily take the Sarno pressure (,
It changes relatively smoothly.

(Example) FIG. 1 shows a first embodiment of the invention.

Located downstream of the damping valve 12, a relief valve 50 and a ridge 51 are provided in parallel.

91 No. 7 valve 50 has an annular valve 53 connected to the spring 5 in a valve body 52 screwed onto the valve case 13, which also serves as the spring seat 14A of the suspension spring 14.
4 to close the valve port 55. The inner circumferential surface of the valve body 52 faces the outer circumferential surface of the piston rod 6 with a predetermined gap, and this gap passage 56 constitutes the throttle 51.

The damping valve 12 is configured as described above, and the valve 21 is urged in the closing direction by the leaf spring 24 and is attracted to the valve seat 20 as the solenoid 11 is energized.

The hydraulic oil that has passed through the damping valve 12 flows back to the oil reservoir chamber 9 via a parallel circuit consisting of the I/NO 7 valve 50 and the throttle 51.

The configuration is as described above, and the other parts are the same as those shown in FIG. 7, so the explanation thereof will be omitted.

Therefore, when the hydraulic oil from the passage 25 of the piston rod 6 passes through the damping valve 12 during the extension stroke of 7+:Ln)7r-, the hydraulic fluid is combined with the excitation force of the solenoid 11 and the spring force of the leaf spring 24. It receives damping resistance based on the combined resistance force.

After passing through the damping valve 12, the relief valve 5
The flow of the hydraulic oil is divided into 0 and 51. In the region where the passing flow rate is small, as shown in FIG. 4, the entire amount of hydraulic oil passes through the gap passage 56 on the inner circumference of the pulp body 52, and the damping resistance increases as a damping force is generated in accordance with the resistance due to the throttle 51. When the set force of the relief valve 50 is exceeded,
The relief valve 50 begins to open, and most of the hydraulic oil now passes through the relief valve 50, generating a corresponding damping force.

Therefore, the resistance force against the passage of hydraulic oil is reduced by the damping valve 12.
and a relief valve 50 and aperture r) 51 in series with this.
Based on this, a damping force as shown in damping characteristic A in FIG. 5 is generated.

In the case of only the damping valve 12, the damping force decreases once, but at this time, the generated damping force is relatively raised due to the resistance of the throttle 51 and the relief valve 50. There is no sudden drop after taking pressure off.

As a result, as shown in FIG. 6, the damping force waveform a changes smoothly with respect to displacement, and the absorbed energy also increases by the area shown by diagonal lines.

In addition, as mentioned above, in the compression side stroke, due to the influence of the base valve (not shown), the generated damping force is relatively lower than that on the rebound side, but as a result of the weakening of the peak of the damping force,
The damping force change characteristics become smooth.

By the way, the damping force characteristics are based on the relief valve 50 and the aperture 51.
You can freely adjust it by changing the settings of
For this reason, for example, the solenoid 11 and damping valve 12 glue 7
Even if the spring 24 is left as is, the damping force retention can be changed depending on the applicable model.

In other words, in combination with changes in the characteristics of the solenoid 11 and the like, this also means that the adjustment range of the damping force becomes significantly larger than in the past.

In order to make the absolute value of the generated damping force the same, it is only necessary to reduce the resistance value of the ljf valve 1 and 2 by the amount that the relief valve 50 and the crest 51 are provided.

FIG. 2 shows another embodiment of the present invention, in which an oriice serving as a throttle 51 is formed through a part of the valve body 52 of the relief valve 50.

Note that the spring seat 14A is formed separately from the valve body 52, and the valve body 52 is tightly fitted to the outer periphery of the piston rod 6 without any gaps.

This embodiment also produces damping force characteristics similar to those of the first embodiment.

(Effects of the Invention) As described above, according to the present invention, the IJ-
With 7 valves and apertures installed, the damping force changes smoothly, and the degree of freedom in adjusting and setting the damping force is increased.Moreover, the vibration absorption energy is also increased, allowing the optimum damping force characteristics to be adjusted according to the requirements. It has the effect of being able to be granted.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of main parts showing a first embodiment of the present invention, and a second embodiment of the present invention is shown in FIG.
The figure is a sectional view of main parts showing the second embodiment, Figure 3 is a characteristic diagram showing the relationship between the lift of the damping valve and the spring force, and Figure 4 is a characteristic diagram showing the relationship between the flow rate of hydraulic oil passing through and the generated pressure. Figure 5 is a characteristic diagram showing the relationship between excitation speed and generated damping force, Figure 6 is a characteristic diagram showing the relationship between front 7-o displacement and damping force, and Figure 7 is a cross-sectional view of the conventional device. It is. 1... Water tube, 2... Inner tube, 3... Dumper, 6... Piston rod, 7, 8...
...Oil chamber, 9...Oil sump chamber, 11...Tsure/id, 1
2... Damping valve, 25... Passage, 50... Relief pulp, 51... Throttle. Patent applicant Kayabae Gyo Co., Ltd. Figure! 51!1 Liquid port tdt

Claims (1)

[Claims] The inner tube is housed in the outer tube, and a damper is built inside the outer tube, and an oil sump chamber is defined inside the inner tube to compensate for the inflow and outflow of hydraulic oil corresponding to the volume of the piston rod inserted into the damper. A damping valve that is attracted and closed by the excitation of a solenoid is provided in the upper part of the inner tube, and a passage communicating with an oil chamber inside the damper formed by penetrating the piston rod of the damper is provided through the damping valve. 1. A front fork with adjustable damping force, characterized in that the front fork opens into an oil reservoir chamber, and a parallel circuit including a relief valve and a throttle is inserted in series with the damping valve.