JPH07113434A - Shock absorber of damping force control type - Google Patents

Abstract

PURPOSE:To prevent damping force from changing before and after adjustment and improve responsiveness upon adjustment. CONSTITUTION:An oil path 16 for adjusting damping force is composed of see-through oil holes 17, 28 bored over a slide valve 22 and a bearing 4 guiding the slide valve 22, and between the valve 22 and the vearing 4 a turning preventing mechanism 35 for restraining circumferential distortion is arranged. The valve 22 is disposed in a space surrounded by the bearing and a valve stopper 29 as well as a solenoid core 20 and a solenoid yoke 21, and the inner circumferential face of the yoke 21 is set with a gap 37 in a face-to-face relation with the outer circumferential face of the valve 22.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a damping force adjustable shock absorber in which the generated damping force is switched between high and low by a solenoid valve.

[0002]

2. Description of the Related Art There have been various proposals for a damping force adjustable shock absorber in which the generated damping force is switched between high and low by a solenoid valve.

For example, in the shock absorber of the damping force adjusting type shown in FIG. 2, a piston 3 that bears a piston rod 2 is slidably inserted into the working cylinder 1 and the inside of the working cylinder 1 is moved by the piston 3. It is divided into an upper hydraulic oil chamber A on the rod side and a lower hydraulic oil chamber B on the bottom side.

The piston rod 2 has an upper hydraulic oil chamber A.
To the bush 5 of the bearing 4 fitted to the upper end of the working cylinder 1 and the packing 8 in the seal case 7 fitted to the casing 6 of the damping force adjusting mechanism 18 to extend outward.

The piston 3 has an extension side damping force generating valve 9
And a check valve 10 for suction on the pressure side, respectively, and an upper hydraulic oil chamber A on the rod side and a lower hydraulic oil chamber B on the head side via the extension side damping force generating valve 9 and the check valve 10 for pressure side suction. Are in communication with each other.

A base valve 13 is provided at the bottom of the working cylinder 1 so as to be sandwiched between the lower end of the working cylinder 1 and a bottom cap 12 fitted to the lower bottom of the outer tube 11.

The outer tube 11 surrounds the working cylinder 1 in a concentric state, and the upper end of the outer tube 11 is connected to the casing 6 to form a reservoir chamber C between the working cylinder 1 and the outer tube 11. There is.

Similarly to the piston 3 described above, the base valve 13 also has a compression side damping force generating valve 14 and an extension side suction check valve 15, and these compression side damping force generating valve 14 and extension side suctioning valve 14 are provided. The lower hydraulic oil chamber B on the head side and the reservoir chamber C communicate with each other through the check valve 15.

On the other hand, the upper hydraulic oil chamber A directly communicates with the reservoir chamber C from the oil hole 16 formed in the bearing 4 through the annular groove 17 formed on the outer peripheral surface and the casing 6. A damping force adjusting mechanism 18 is provided in the casing 6 at the outlet.

In the case of this conventional example, the damping force adjusting mechanism 18 has a solenoid 19 seated on the bottom of the casing 6, a cylindrical solenoid core 20 inserted through the solenoid 19, and the solenoid core 20. It is composed of an annular solenoid yoke 21 arranged on the solenoid 19 so as to face the outer surface of the upper end of the above, and a solenoid valve 20 and a slide valve 22 arranged above the solenoid yoke 21.

The solenoid core 20 has a collar portion 20 at the upper end.
Further, a has a slit 23 penetrating in the inner peripheral surface in the axial direction, and the slit 23 is used as an oil passage to contact the inner peripheral surface with the outer peripheral surface of the working cylinder 1, and
By engaging the upper end flange portion 20a with the upper portion of the solenoid 19, the upper working oil chamber A and the reservoir chamber C are axially positioned while ensuring communication.

The solenoid yoke 21 is pressed onto the solenoid 19 by a spring 26 which is interposed between the slide valve 22 and a spring receiver 25 which is locked by a stop ring 24. In this state, the upper surface of the solenoid yoke 21 is the solenoid. The core 20 is kept flush with the upper surface of the collar portion 20a.

The slide valve 22 has a flange portion 22a formed at the lower end, which faces the solenoid core 20 and the upper surface of the solenoid yoke 21, and which is interposed between the return spring 27 and the upper surface of the solenoid 19. And I always receive the force to go up.

The collar portion 22 of the slide bubble 22.
A slit 28 is formed in the portion a, and when the slide valve 22 is pushed upward by the return spring 27, the slit 28 opens the annular groove 17 provided in the bearing 4.

The upper limit position of the slide valve 22 is
It is regulated by abutting against a valve stopper 29 fixed by being sandwiched between the bearing 4 and the seal case 7.

The casing 6, the solenoid core 20, the solenoid yoke 21, and the slide valve 22 are each made of a magnetic material, and when the solenoid 19 is energized to excite it, magnetic flux is generated by the casing 6 and the solenoid yoke 21 ,. It flows through a loop path composed of the slide valve 22 and the solenoid core 20, and the solenoid 19 causes the slide valve 22 to return to the return spring 27.
Aspirate against.

Then, in this state, the slide valve 22 closes the annular groove 17 formed in the bearing 4, and cuts off the damping force adjusting oil passage for communicating the upper working oil chamber A with the reservoir chamber C.

When the solenoid 19 is demagnetized, the restoring force of the return spring 27 raises the slide valve 22 to the position where it is locked by the valve stopper 29.
At this time, as described above, the slit 28 of the slide valve 22 opens the annular groove 17 on the bearing 4 side.

As a result, the damping force adjusting oil passage is opened, and the upper working oil chamber A is communicated with the reservoir chamber C through the slit 23 provided in the solenoid core 19.

Thus, when the solenoid 19 is excited,
When the shock absorber expands and contracts, the flow of hydraulic oil returning from the upper hydraulic oil chamber A directly to the reservoir chamber C through the oil hole 16 and the annular groove 17 can be interrupted, and the damping force generated at that time can be increased.

[0021]

However, in the above-mentioned conventional damping force adjustable shock absorber,
The communicative passage area between the upper hydraulic oil chamber A and the reservoir chamber C, which is formed by the rise of the slide valve 22 due to the demagnetization of the solenoid 19, has a lap size of the annular groove 17 provided in the bearing 4 and the slit 28 provided in the slide valve 22. Determined by

Therefore, in order to maintain the communication passage area with high accuracy, the relative positional relationship between the annular groove 17 on the bearing 4 side and the slit 28 on the slide valve 22 side must be strictly determined.

For that purpose, the processing position of the annular groove 17 with respect to the bearing 4 and the upper end position of the slit 28 in the slide valve 22 must be processed with high precision, and as a result, the dimensional control of these is only troublesome. In addition, there is a disadvantage that the damping force characteristics easily vary.

Further, the lower end of the slide valve 22 is the collar portion 2.
Since it becomes 2a and protrudes to the outer periphery, the resistance of the hydraulic oil acts on the lower end flange portion 22a during the operation of the slide valve 22, and the operation of the slide valve 22 becomes slow, resulting in poor responsiveness. Also has.

Further, when the solenoid 19 is excited, a part of the magnetic flux does not pass between the solenoid core 20 and the lower end flange portion 22a of the slide valve 22 but directly flows between the solenoid core 20 and the solenoid yoke 21 or upward. It leaks through the gap between the cylindrical portion of the slide valve 22 and the casing 6.

In addition to the above, in the magnetic circuit, the flange portion 20a of the solenoid core 20 and the slide valve 22 are provided.
Between the collar portions 22a of the slide valve 22 and the collar portion 2 of the slide valve 22.
The air layer portions are present in series at two locations between 2a and the solenoid yoke 21.

Since these air layers are hard to pass magnetism, and therefore, there are two magnetic resistances in series in the circuit, the attraction force of the solenoid 19 is the slide valve 22.
Rapidly decreases as the distance from the solenoid core 20 and the solenoid yoke 21 increases.

Therefore, in order to overcome the return spring 27 and suck the slide valve 22, the area of the suction portion of the collar portion 22a of the slide valve 22 needs to be sufficiently large, and as a result, the solenoid 19 is large. As a result, not only is it disadvantageous in terms of assembly and cost, but also the operation response itself of the solenoid valve 22 is deteriorated.

Therefore, an object of the present invention is to provide a damping force adjusting type shock absorber using a solenoid, which has almost no variation in the generated damping force before and after the adjustment, and has an excellent responsiveness at the time of adjustment. That is.

[0030]

According to the present invention, the above object is to provide a slide valve and a bearing for guiding the slide valve with a damping force adjusting oil passage that directly communicates the upper working oil chamber with the reservoir chamber. A detent mechanism is formed between the slide valve and the bearing, the detent mechanism being formed of a through oil hole that penetrates both the sliding contact surfaces.

The slide valve is provided in a space surrounded by a bearing, a solenoid yoke arranged to face the outer peripheral surface of the bearing, and a valve stopper and a solenoid core for limiting the vertical movement end of the slide valve. Deploy.

This is achieved by fixing the solenoid core in contact with the casing, and by facing the inner peripheral surface of the solenoid yoke to the outer peripheral surface of the slide valve at a predetermined interval.

[0033]

In other words, according to the above-described structure, when the damping valve adjusting oil passage for directly communicating the upper working oil chamber with the reservoir chamber is formed over the slide valve and the bearing, the contact with the valve stopper on the bearing side is performed. The relative positional relationship between the slide valve and the bearing is regulated with the contact surface as a reference surface, and a through oil hole is formed between the slide valve and the bearing in a state where these are integrated.

With this arrangement, the through oil hole on the slide valve side and the through oil hole on the bearing side can be surely aligned with each other by the valve stopper when the solenoid is demagnetized.

As a result, the opening area of the damping force adjusting oil passage, which is created by both through-holes, is always maintained with high precision before and after the solenoid is excited, and the generated damping force varies before and after the adjustment. Will be prevented.

In constructing the solenoid magnetic circuit between the slide valve and the solenoid yoke, the outer peripheral surface of the slide valve is opposed to the inner peripheral surface of the solenoid yoke with a predetermined space.

As a result, not only the area where the slide valve and the solenoid yoke face each other increases and the area through which the magnetic flux passes increases, but also the facing area of this portion is kept constant regardless of the operation of the slide valve. The magnetic resistance of can be made extremely small.

As a result, the portion of the air layer which becomes the magnetic resistance is only one place between the solenoid core and the slide valve, the magnetic efficiency is increased, and the solenoid is miniaturized accordingly, and the assembly to the shock absorber is facilitated. Become.

[0039]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below. In this description, the other parts except the damping force adjusting mechanism of the main part have the same structure as the above-mentioned conventional example (see FIG. 2). Therefore, only the damping force adjusting mechanism will be illustrated and described here to prevent duplication of description.

In order to facilitate understanding in the above description, the same functional parts as those in the conventional example will be described using the same reference numerals.

FIG. 1 shows an example of a damping force adjusting mechanism 18 used in a damping force adjusting type shock absorber using a solenoid according to the present invention.

That is, the damping force adjusting mechanism 18 includes a solenoid 19 arranged inside the casing 6, a solenoid core 20 inserted into the bobbin 19a of the solenoid 19, and a bearing 4 arranged above the solenoid core 20. Slide valve 2 arranged on the outer peripheral surface of
2 and a solenoid yoke 21 arranged on the bobbin 19a of the solenoid 19.

The bearing 4 is provided with a valve stopper 29 on the lower surface of a seal case 7 containing a packing 8 for sealing the outer peripheral surface of the piston rod 2, as in the above-mentioned conventional example.
The piston rod 2 is guided through the bush 5 fitted to the inner peripheral surface of the piston rod 2.

Similarly to the conventional example, the solenoid 19 also has a seal 3 between the solenoid bobbin 19a and the casing 6.
Casing 6 with 0, 31 interposed to seal the part
It is seated at the bottom of.

On the other hand, unlike the conventional example, the solenoid core 20 is formed into a cylindrical shape, is positioned and attached by press-fitting the outer peripheral surface of the lower end into the casing 6, and has an inner peripheral surface having a slit 23. Are opposed to each other with a gap 32 between the outer peripheral surface of the working cylinder 1.

The slide valve 22 is also arranged so that its lower end faces the upper end of the solenoid core 20 and is vertically movable along the outer peripheral surface of the bearing 4, and the upper hydraulic oil chamber A and the reservoir chamber C are communicated with each other. Oil passage 16 for adjusting damping force
Are formed of through oil holes 17 and 28 drilled through the sliding contact surfaces of the bearing 4 and the slide valve 22.

In the processing, the through oil holes 17 and 28 are formed simultaneously by using the contact surface 4a of the bearing 4 against the valve stopper 29 and the upper end surface of the slide valve 22 as reference surfaces.

In addition, the bearing 4 and the slide valve 22
In between, the pin 3 driven into the bearing 4 side in order to restrain the through oil holes 17 and 28 from shifting in the circumferential direction.
3 and a vertical groove 34 on the slide valve 22 side into which the pin 33 is fitted.

As a result, the slide valve 22 can move only up and down with respect to the bearing 4.
Therefore, the through oil holes 17 and 28 do not shift in the circumferential direction.

Moreover, since the through oil holes 17 and 28 are formed by the simultaneous processing as described above, the through oil holes 17 and 28 can be processed accurately and easily without shifting the vertical position of both.

Furthermore, the solenoid core 2 described above
When press-fitting 0, a jig having a thickness corresponding to a predetermined stroke of the slide valve 22 is inserted between the upper end of the slide valve 22 and the valve stopper 29 on the seal case 7 side, and the casing 6 is sealed in this state. The case 7 is fitted to a predetermined position.

As a result, with the slide valve 22 kept at the maximum stroke, the solenoid core 20
Is pushed by the slide valve 22 and press-fitted into the casing 6.

Therefore, after that, if the seal case 7 is removed from the casing 6 and the jig is taken out,
Finally, when the seal case 7 is fitted into the casing 6 to assemble the damping force adjusting mechanism 18, the slide valve 2
The gap amount between the lower end of 2 and the upper end of the solenoid core 20 is kept at a predetermined value.

Further, unlike the conventional example, the solenoid yoke 21 is also arranged on the solenoid bobbin 19a with its inner peripheral surface facing the outer peripheral surface of the slide valve 22 with a predetermined gap 37 therebetween. Moreover, the outer peripheral surface is in contact with the inner peripheral surface of the casing 6.

Thus, with the excitation of the solenoid 19,
The magnetic flux flows through the loop path formed by the casing 6, the solenoid yoke 21, the slide valve 22, and the solenoid core 20.

Moreover, in the above, the facing area between the solenoid yoke 21 and the slide valve 22 is always kept constant regardless of the control operation of the slide valve 22, and this portion does not become a magnetic resistance.

Therefore, unlike the conventional example, there is only one place between the solenoid core 20 and the slide valve 22 in the air layer which becomes the magnetic resistance, the magnetic efficiency is increased, and the solenoid 19 is reduced in size accordingly, resulting in a shock. It is easy to assemble to the absorber.

The bearing 4, the valve stopper 29 and the solenoid bobbin 19a are made of a non-magnetic material, and the solenoid core 20, the solenoid yoke 21, the slide valve 22 and the casing 6 containing them are made of a magnetic material. There is.

Further, in the case of this embodiment, the return spring 27 which keeps the slide valve 22 at the upper limit position is composed of two disc springs, a first return spring 27a and a second return spring 27b.

The first return spring 27a is interposed between the first step portion 36a formed on the slide valve 22 and the upper surface of the solenoid yoke 21 at the inner and outer peripheral ends thereof, and the slide valve 22 is valved by the restoring force. It also serves to hold the stopper 29 at the upper limit position.

On the other hand, the second return spring 27b
Has a solenoid yoke 21 and a valve stopper 2 at the outer peripheral end.
The second step portion 3 of the slide valve 22 is fixed by sandwiching it between the holding members 38 and 39 interposed between the slide valve 22 and the holding member 38.
6b face each other with a gap.

Then, the above-described respective components are sequentially incorporated into the casing 6 and the seal case 7, and finally the casing 6 and the seal case 7 are joined by means such as welding, whereby the whole assembly is assembled into one assembly. It is configured as a reduced damping force adjusting mechanism 18.

The assembly of the damping force adjusting mechanism 18 is such that the lower ends of the bearing 4 and the casing 6 are fitted and fixed to the upper ends of the working cylinder 1 and the outer tube 11 on the shock absorber side, respectively. It is attached to the upper part of the shock absorber.

Thus, the damping force adjusting mechanism 1 of this embodiment is
According to FIG. 8, when the solenoid 19 is energized and excited, the magnetic flux from the casing 6 to the solenoid yoke 21,
A loop is drawn through the slide valve 22 and the solenoid core 20, and the slide valve 2 is moved by the solenoid 19.
2 is attracted against the return spring 27.

At this time, if the voltage applied to the solenoid 19 is limited, the slide valve 22 bends only the first return spring 27a and descends, and the damping force adjusting oil passage 16 formed by the through oil holes 17 and 28 is formed. squeeze.

If a voltage having a predetermined value is applied to the solenoid 19, the slide valve 22 is connected to the first return spring 27a and then to the second return spring 27b.
The oil passage 16 for adjusting the damping force is closed while also being bent while descending.

Thus, by exciting the solenoid 19, the flow of the working oil returning from the upper working oil chamber A to the reservoir chamber C directly through the damping force adjusting oil passage 16 at the time of the expansion and contraction operation of the shock absorber is restricted or blocked. The damping force generated by the shock absorber that expands and contracts is calculated by the solenoid 19
It is increased according to the magnitude of the voltage applied to the.

[0068]

As described above, according to the first aspect of the present invention, the oil passage for adjusting the damping force is formed by the through oil holes formed through the sliding contact surfaces of the bearing and the slide valve. By configuring the oil holes by simultaneous processing, the relative positions of the two can be accurately created.

Therefore, the opening area of the oil passage for adjusting the damping force that returns directly from the upper hydraulic oil chamber to the reservoir chamber during expansion and contraction of the shock absorber is always maintained with high accuracy to prevent the variation of the generated damping force before and after the adjustment. It has the advantage of being able to

According to the second aspect of the invention, in addition to the above effects, the area of the air layer facing the solenoid yoke and the interval are always kept constant regardless of the operation of the slide valve, and the air layer portion becomes the magnetic resistance. Since it is possible to provide only one position between the solenoid core and the slide valve, the magnetic efficiency is increased accordingly, the solenoid can be downsized, and the damping force adjusting mechanism can be easily assembled to the shock absorber.

Further, according to the invention of claim 3, in addition to the above respective effects, by fixing the solenoid core to the casing by the press-fitting means, the slide valve and the solenoid are irrespective of the dimensional error of each component. It is possible to accurately set the gap amount between the cores, and thereby to improve the responsiveness at the time of adjusting the damping force as well as preventing the variation of the generated damping force.

Furthermore, according to the fourth aspect of the present invention, magnetic flux leakage is prevented to increase the magnetic flux density between the slide valve and the solenoid core to prevent the generated damping force from varying and to improve the responsiveness at the time of adjusting the damping force. Each of the above effects of miniaturizing the solenoid can be made more remarkable.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view showing a state before adjustment of a damping force adjusting mechanism according to an embodiment of the present invention.

FIG. 2 is a vertical sectional front view of a shock absorber including a damping force adjusting mechanism as a conventional example, in which the damping force adjusting mechanism is in a state after adjustment.

[Explanation of symbols]

 4 bearing 6 casing 16 oil passage 17 through oil hole 18 damping force adjusting mechanism 19 solenoid 19a solenoid bobbin 20 solenoid core 21 solenoid yoke 22 slide valve 23 slit 29 valve stopper 32 gap 35 detent mechanism 37 gap A upper working oil chamber C reservoir Room

Claims (4)

[Claims] 1. An upper hydraulic oil chamber and a reservoir chamber are communicated with each other through a damping force adjusting oil passage, and a slide valve controlled by an exciting action of a solenoid is disposed in the middle of the oil passage, and the slide valve is provided. In a shock absorber capable of adjusting the damping force generated along with the control operation of the valve, an oil passage for adjusting the damping force is formed by a through oil hole that penetrates both slide contact surfaces of the slide valve and the bearing that guides the slide valve. A damping force adjustable shock absorber, characterized in that a detent mechanism for constraining a displacement of the slide valve and the bearing in the circumferential direction is disposed between the slide valve and the bearing. 2. A slide valve is arranged in a space surrounded by four parts of a bearing, a solenoid yoke arranged to face an outer peripheral surface of the bearing, and a valve stopper and a solenoid core for limiting a vertical movement end of the slide valve. The damping according to claim 1, wherein the solenoid core is fixed in contact with the casing, and the inner peripheral surface of the solenoid yoke is opposed to the outer peripheral surface of the slide valve at a predetermined interval. Force adjustable shock absorber. 3. A slit for guiding an upper hydraulic oil chamber to a reservoir chamber is formed in a solenoid core, a lower portion of the solenoid core is projected further downward from a lower end of a solenoid bobbin, and a lower portion of the solenoid core is press-fitted into a casing. 3. The damping force adjustable shock absorber according to claim 1 or 2, wherein the shock absorber is fixed. 4. The bearing, the valve stopper, and the solenoid bobbin are made of a non-magnetic material, and the solenoid yoke, the solenoid core, the slide valve, and a casing containing them are made of a magnetic material. The damping force adjustable shock absorber described in 3.