JPH048938A - Damper - Google Patents

Abstract

PURPOSE:To lessen delay in the responsiveness of damping force by making up an orifice mutually connecting a first and a second auxiliary oil chamber, out of a throttle hole formed in a switch-over valve, and of a mushroom valve body provided for a plunger in a damper operated by the exciting current of a linear solenoid. CONSTITUTION:At the time of compression of a damper 18, the working oil of a high pressure side main oil chamber 54 flows into a first auxiliary oil chamber 68 from a check valve 76 at the early stage of compression, and it then flows in a second auxiliary oil chamber 70 through a gap between the throttle hole 72a of an orifice 72 and a valve body 72b. The hydraulic pressure of the first auxiliary oil chamber 68 is exerted on the upper surface of the valve body 72b, so that it thereby pushes a plunger 82 down, which is integrated with valve body 72b, against the pressure of a linear solenoid 80. When the plunger 82 is lowered down the pressure of the second auxiliary oil chamber 70 runs away to a low pressure side main oil chamber 56 through a check valve 84, and a switchover valve 66 falls dawn at high speeds with the pressure difference increased between the upper and lower surfaces of the switch-over valve 66, so that the high pressure side main oil chamber 54 is thereby communicated with the lower pressure side main oil chamber 56 through oil passages 88 and 90. When the pressure difference between both of the main oil chambers 54 and 56 is decreased, both of the switch-over valve 66 and the plunger 82 are lifted up, so that the passages 88 and 90 are thereby interrupted. During compression, the switch-over valve 66 is vertically moved repeatedly.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a damping force control device applied to a damper that controls damping force using an excitation current of a linear solenoid.

(Background of the invention) In attenuators used in vehicles such as automobiles and motorcycles,
It is desirable to be able to freely change the damping force depending on the driving conditions. Therefore, the applicant has proposed a system that detects the amount and speed of expansion and contraction of a cushion unit that integrates a damper and a coil spring, and changes the orifice provided on the piston of the damper using a linear solenoid (for example, Ganpei 1-1
(See No. 233).

The attenuator used here has the structure shown in FIG.

That is, a piston 3 defining two main oil chambers 1.2 in the cylinder, a switching valve 6 defining first and second auxiliary oil chambers 4.5 in this piston 3, and a switching valve 6 defining two main oil chambers 1.2 in the cylinder.・The orifice 7 interposed between the second auxiliary oil chambers 4.5 and the second auxiliary oil chamber 5
A plunger 9 is moved to the low pressure side main oil chamber side 1 or 2 against the set pressure of the linear solenoid 8 to reduce the pressure in the second auxiliary oil chamber 5. While introducing the hydraulic pressure in the oil chamber, the internal pressure of the second auxiliary oil chamber 5 is reduced by the movement of the plunger 9, so that the switching valve 6
is moved to open the oil passage between the dual oil chambers 1 and 2 to control the damping force. In other words, the amphibious oil chamber 1
．． The switching valve 6 that opens and closes the oil passage between the first and second valves is connected to the first and second switching valves 6 on both sides.
When moving due to the differential pressure between the two auxiliary oil chambers 4.5,
The internal pressure of the auxiliary oil chamber can be controlled by the linear solenoid set pressure.

However, in this case, the oil pressure in the main oil chamber 1 or 2 on the high pressure side is
Since the oil pressure in the second auxiliary oil chamber 5 is sequentially guided to the first auxiliary oil chamber 4, the orifice 7, and the second auxiliary oil chamber 5 is controlled by a linear solenoid, it takes time to operate. Furthermore, due to the presence of the orifice 7, the generation of the differential pressure in the 1st and 2nd auxiliary oil chambers 4.5 is delayed, and the operation of the switching valve 6 is also delayed, from the time the signal arrives until the damping force is actually generated. There was a problem with the response delay.

A solid line A in FIG. 5 represents this conventional characteristic.

(Object of the Invention) The present invention was made in view of the above circumstances, and provides an attenuator that solves the problems in the attenuator shown in Fig. 4 and improves the responsiveness of damping force generation. The purpose is to provide.

(Structure of the Invention) According to the present invention, the object is to provide a switching valve that defines first and second auxiliary oil chambers in a piston that defines two main oil chambers in a cylinder; the aperture hole interposed between the
a plunger that is moved from the auxiliary oil chamber to the low-pressure main oil chamber side against the linear solenoid set pressure to reduce the pressure in the second auxiliary oil chamber, and the plunger is provided with a plunger that is moved from the auxiliary oil chamber to the low-pressure main oil chamber side to reduce the pressure in the second auxiliary oil chamber; At the same time, the plunger is pushed down by the pressure in the first auxiliary oil chamber and the pressure in the second auxiliary oil chamber is reduced, thereby moving the switching valve and opening the oil passage between the two main oil chambers to control the damping force. This is achieved by an attenuator characterized by the following.

(Embodiment) FIG. 1 is a sectional view of a main part of an embodiment of the present invention, FIG. 2 is a conceptual diagram and functional block diagram when the same is used, and FIGS. 3A and 3B are explanatory diagrams of its operation.

In FIG. 2, reference numeral 10 indicates a motocross motorcycle, and a rear wheel 12 is held at the rear end of a rear arm 14. Reference numeral 16 designates a cushion unit consisting of a damper 18 and a coil spring 22, and its upper end is pivotally supported by the frame, while its lower end is directly connected to the rear arm 14 and applies a downward return force to it.

26 is the stroke of the cushion unit 16.

That is, it is a potentiometer for detecting the position X of the piston 52, which will be described later. This potentiometer 26 is mounted on the frame, and the vertical movement of the rear arm 14 is transmitted to this potentiometer 26 by links 30, 32. The piston position signal X output by the potentiometer 26 is sent to the control device 34 via an input interface (not shown).

Next, the attenuator 18 will be explained. In FIG. 1, 50 is a cylinder, and 52 is two main oil chambers 54 within this cylinder 50.
A piston defining 56. The piston 52 has a solenoid case 60 screwed onto the upper end of the piston rod 58.
A piston body 62 is screwed onto the solenoid case 60 from above, and a cap 64 is screwed onto the upper end of the piston body 62. piston body 6
A switching valve 66 is housed within the piston body 62, and this switching valve 66 defines a first sub-oil chamber 68 and a second sub-oil chamber 70 within the piston body 62. This switching valve 66 is provided with an orifice 72 interposed between oil chambers 68 and 70 on both sides. Further, the switching valve 66 is biased toward the first auxiliary oil chamber 68 by a spring 74 . The oil pressure of the main oil chamber 54 or 56 on the high pressure side is introduced to the first auxiliary oil chamber 68 through a check valve 76.78 from each of the main oil chambers 54,56.

The orifice 72 extends from a throttle hole 72a provided in the switching valve 66 and a plunger 82, which will be described later.
and an umbrella-shaped valve body 72b located inside.

80 is a linear solenoid, and the solenoid case 6
It is contained in 0. This solenoid 80 applies a substantially constant upward thrust to the plunger 82 in response to the excitation current. On the tip side of this plunger 82,
The above-mentioned umbrella-shaped valve body 72b is integrally connected through the small diameter portion.

Next, the operation will be explained using FIGS. 3A and 3B. When the damper 18 is compressed, the hydraulic oil in the high pressure side main oil chamber 54 enters the first auxiliary oil chamber 68 from the check valve 76 at the initial stage of compression.
It enters the second auxiliary oil chamber 70 through the gap between the throttle hole 72a of the orifice 72 and the valve body 72b. At this time, the oil pressure in the first auxiliary oil chamber 68 acts on the upper surface of the valve body 72b to push down the valve body 72a and the plunger 82 integrated therewith against the pressure of the linear solenoid 80 (FIG. 3A). When the plunger 82 descends, the pressure in the second auxiliary oil chamber 70 escapes through the check valve 84 to the main oil chamber 56 on the low pressure side. As a result, the differential pressure between the upper and lower surfaces of the switching valve 66 increases, so the switching valve 66 descends at high speed (FIG. 3B). As a result, the high-pressure side main oil chamber 54 communicates with the low-pressure side main oil chamber 56 via the oil passages 88 and 90, and the hydraulic oil flows into the low-pressure side main oil chamber 56. When the differential pressure between the two oil chambers 54 and 56 decreases, the switching valve 66 and plunger 82 rise to shut off the oil passages 88 and 90. During compression, the switching valve 66 operates while repeatedly moving up and down. Oil is being supplied intermittently.

During the extension operation, the check valve 76 through which hydraulic oil passes is changed to 78.
Also, since 84 is changed to 86 and the rest is exactly the same, the explanation thereof will not be repeated.

In this way, since the pressure of the first auxiliary oil chamber 68 is directly applied to the umbrella-shaped valve body 82b formed at the tip of the plunger 82, the moving speed of the plunger 82 becomes faster, and the time change t of the damping force F increases.
As shown by the broken line B in FIG. 5, the change in the curve becomes smaller, and the damping force F quickly stabilizes.

Next, the control device 34 will be explained based on FIG. 2.4. This control device 34 is constituted by a digital arithmetic device except for a portion of a current control means 110 which will be described later.

Reference numeral 100 denotes a piston position calculation means for calculating the piston position X based on the position signal χ of the potentiometer 26. That is, the potentiometer 26 has a link 30.
Since the swing of the rear arm 14 is transmitted through the
Piston position X and potentiometer 26 output voltage are not proportional.

The piston position calculating means 100 corrects this relationship to obtain the correct piston position X.

102 is a piston speed calculation means, which calculates the piston speed V by, for example, time differentiation of the piston position X. 10
Reference numeral 4 denotes a memory means composed of a semiconductor memory such as a ROM. This memory means 104 stores maps that determine the optimum damping force F as a function of the piston position X and the piston speed V for compression and expansion. The damping characteristics can be changed depending on the vehicle type, driving conditions, etc., and it is possible to memorize in advance various characteristics that cannot be obtained with conventional orifice control, such as the characteristic that the damping force decreases as the piston speed increases. It is also possible to select and use preferable characteristics depending on the conditions. Note 10
Reference numeral 6 denotes a correction means, which stores data for correcting the contents of the map based on the temperature of hydraulic oil and the like. 108 is a damping force calculating means, which calculates the optimum damping force F for the piston position X and the piston speed (2) based on the map in the memory means 104.

110 is a linear solenoid 80 to obtain the optimum damping force.
This is a current control means that performs pulse width control (PWM) on the excitation current. This means 110 supplies an intermittent current with a predetermined duty ratio to the solenoid 80.
0 pressure is controlled. As a result, the damping force of the attenuator 18 is controlled almost in real time to the optimum value determined by the map.
It is possible to manage the damping force so that it has different damping force characteristics during compression and extension.

(Effects of the Invention) As described above, the present invention has an orifice connecting the first and second auxiliary oil chambers formed by a throttle hole formed in the switching valve and an umbrella-shaped valve body provided in the plunger. Because there is, the first
The pressure in the auxiliary oil chamber acts directly on the umbrella-shaped valve body, causing the plunger to move quickly.

Therefore, the switching valve also operates quickly, and damping force is generated quickly. In other words, the response delay is reduced by 4 degrees.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a main part of an embodiment of the present invention, Fig. 2 is a conceptual diagram and functional block diagram when using the same, Figs. 3A and 3B are explanatory diagrams of operation, and Fig. 4 is a main part of a conventional device. The cross-sectional view and FIG. 5 are attenuation characteristic diagrams. 18...Attenuator, 52...Piston, 54.56...Main oil chamber, 6
6...Switching valve, 68.70...First and second auxiliary oil chambers 72...Orifice, 72a...Aperture hole, 72b...Valve body, 82...Plunger. Patent applicant Yamaha Motor Co., Ltd.

Claims (1)

[Claims] A first oil chamber is located in the piston that defines two main oil chambers in the cylinder.
- A switching valve defining a second auxiliary oil chamber, a throttle hole interposed between the two auxiliary oil chambers, and an umbrella-shaped valve body extending into the throttle hole are formed at the tip, and the second auxiliary oil chamber a plunger that is moved from the chamber toward the low-pressure main oil chamber against the linear solenoid set pressure to reduce the pressure in the second auxiliary oil chamber, and guides the hydraulic pressure of the high-pressure main oil chamber to the first auxiliary oil chamber. On the other hand, when the plunger is pressed down by the pressure in the first auxiliary oil chamber and the pressure in the second auxiliary oil chamber is reduced, the switching valve is moved to open the oil passage between the two main oil chambers and control the damping force. An attenuator characterized by: