JPH048936A - Damper - Google Patents

Abstract

PURPOSE:To keep running stably by disposing a diameter widening sections in a row at the tip end side of a plunger via small diameter sections, and thereby restricting the flow-out of oil within a second auxiliary oil chamber when exciting current is interrupted in a damper operated by the exciting current of a linear solenoid. CONSTITUTION:In an early stage of compression at the time of normal operations, when exciting current is applied to a linear solenoid 80, the working oil within a high pressure side main oil chamber 54 flows into a first auxiliary oil chamber 65 through a check valve 76, and it then flows in a second auxiliary oil chamber 70 through an orifice 72. A plunger 82 is pressed down with internal pressure increased, so that the working oil runs away to a low pressure side main oil chamber 56 through a check valve 84. A switch-over valve 66 is lowered down due to the pressure difference caused by the aforesaid operation, the high pressure side main oil chamber 54 is communicated with the low pressure side main oil chamber 56 via oil passages 88 and 90. When the pressure difference between both of the main oil chambers 54 and 56 is decreased, the plunger 82 is lifted up while the internal pressure of a second auxiliary oil chamber 70 is increased, so that the oil passages 88 and 90 are thereby interrupted with the switch-over valve 66 lifted up. During compression, the switch-over valve 66 is vertically moved repeatedly. When exciting current is interrupted, a plunger hole is throttled by the diameter widening section 82b of the plunger 82, the switchover valve is fairly pressed down by the pressure difference, but sufficient damping force is thereby generated.

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, so the applicant detected the amount and speed of expansion and contraction of a cushion unit that integrates a damper and a coil spring, and detected the amount and speed of expansion and contraction of a cushion unit that integrates a damper and a coil spring. proposed a linear solenoid to change the
233), the damper used here includes a piston that defines two main oil chambers in the cylinder, a switching valve that defines first and second auxiliary oil chambers in this piston, and a switching valve that defines two main oil chambers in the piston. 1. An orifice interposed between the second auxiliary oil chamber and a plunger that is moved toward the low-pressure main oil chamber side against the linear solenoid set pressure by the pressure in the second auxiliary oil chamber to reduce the pressure in the second auxiliary oil chamber. The hydraulic pressure in the high-pressure side main oil chamber is guided to the first auxiliary oil chamber, while the pressure in the second auxiliary oil chamber is reduced by the movement of the plunger, thereby moving the switching valve and connecting both main oil chambers. The damping force is controlled by opening the oil passage between the two.

Here, the plunger is pressed toward the second auxiliary oil chamber by the linear solenoid, and the pressing force increases or decreases depending on the increase or decrease of the excitation current of the linear solenoid.

Therefore, if this excitation current were to be cut off due to a failure of the electric control circuit, the linear solenoid would move and the switching valve would also easily move.

For this reason, the damping force becomes extremely small. For example, if such a situation suddenly occurs while the vehicle is running, a problem arises in that the damping force suddenly decreases while the vehicle is running.

(Objective of the Invention) The present invention was made in view of the above circumstances, and even if the excitation current of the near solenoid is suddenly cut off while the vehicle is running and its pushing force suddenly decreases, the damping force can be maintained. The object of the present invention is to provide an attenuator that does not cause a sudden decrease in the value of the vehicle and allows stable running.

(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; an orifice interposed therebetween; and a plunger that is moved toward the low-pressure main oil chamber side against the linear solenoid set pressure by the pressure in the second auxiliary oil chamber to reduce the pressure in the second auxiliary oil chamber, and While introducing the hydraulic pressure in the high-pressure side main oil chamber to the auxiliary oil chamber, the pressure in the second auxiliary oil chamber is reduced by the movement of the plunger, thereby moving the switching valve to open an oil passage between the two main oil chambers and damping the pressure. In the attenuator configured to control force, the plunger has an enlarged diameter section connected to the tip side of the plunger through a small diameter section, and when the excitation current of the linear solenoid is cut off, the enlarged diameter section is connected to the second sub-assembly. This is achieved by a damper characterized in that it restricts the outflow of oil from the oil chamber.

(Example) Fig. 1 is a cross-sectional view of a main part of an embodiment of the present invention, Fig. 2 is a conceptual diagram and a functional block diagram during its use, Figs. 3A to 30 are explanatory diagrams of its operation, and Fig. 4A FIG. 4B is a diagram of damping characteristics during compression and expansion, respectively.

In FIG. 2, reference numeral 1O indicates a motocross motorcycle, and the 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 20, 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 a potentiometer for detecting the stroke of the cushion unit 16, that is, 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 hydraulic pressure of the main oil chamber 54 or 56 on the high pressure side is introduced to the first auxiliary oil chamber 68 from each main oil chamber 54,56 via a check valve 76,78.

80 is a linear solenoid, and the solenoid case 60
is housed in. This solenoid 80 applies a substantially constant upward thrust to the plunger 82 in response to the excitation current.

The tip side of this plunger 82, that is, the second auxiliary oil chamber 70
An enlarged diameter portion 82b is integrally connected to the side via a small diameter portion 82a. When the linear solenoid 80 is energized, the plunger 82 is pushed toward the second auxiliary oil chamber 70, and the enlarged diameter portion 82b moves from the plunger hole to the second
It protrudes toward the auxiliary oil chamber 70 side and moves up and down within the range shown in FIG. 3A and FIG. 3B. Note that the plunger 82 is restricted from descending from the position shown in FIG. Also linear solenoid 8
0, the plunger 82 is allowed to descend from the signal shown in FIG. 3B, and is pushed down by the slight internal pressure of the second auxiliary oil chamber 70.

The enlarged diameter portion 82b narrows the plunger hole as shown in FIG. 3C.

Therefore, during normal operation when excitation current is supplied to the linear solenoid 80, the pressure of the second auxiliary oil chamber 70 is applied downward to the plunger 82, and when the internal pressure of the second auxiliary oil chamber 70 becomes higher than the pressure of the plunger 82, the plunger 82 pressed down,
The hydraulic oil in the second auxiliary oil chamber 70 is released to the main oil chamber 54 or 56 on the low pressure side via the check valve 84 or 86. At this time, due to the pressure reduction in the second auxiliary oil chamber 70, the switching valve 66 moves downward while compressing the spring 74, and the dual oil chamber 54.56 moves into the oil passage 88.9.
0 to allow flow of hydraulic oil between the main oil chambers 54 and 56.

The operation during normal operation will be explained using FIGS. 3A and 3B. During compression of the attenuator 18, at the beginning of the compression (3rd A
Figure) Hydraulic oil in the high pressure side main oil chamber 54 enters the first auxiliary oil chamber 68 from the check valve 76, and from the orifice 72 into the second auxiliary oil chamber 7.
Enters 0. When the internal pressure of the second auxiliary oil chamber 70 rises and becomes higher than the pressure of the plunger 82 of the solenoid 80, the plunger 82 is pressed down (FIG. 3B).
The internal pressure of 0 passes through the check valve 84 to the main oil chamber 56 on the low pressure side.
run away to Therefore, a pressure difference is created between the first and second sub-oil chambers 68,70, the switching valve 66 is lowered, and the high-pressure side main oil chamber 54 communicates with the low-pressure side main oil chamber 56 via the oil passage 88,90. and the hydraulic oil flows into the low-pressure side main oil chamber 56.
When the differential pressure between them decreases, the plunger 82 rises to increase the internal pressure of the second auxiliary oil chamber 70, and the switching valve 66 rises to open the oil passage 88.
．． Block 90. That is, during compression, as shown in the state shown in FIG. 3A, during compression, the switching valve 66 repeatedly moves up and down while supplying the hydraulic oil 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 an abnormal situation where the excitation EBt flow of the linear solenoid 80 is cut off, the plunger 82 is pushed down by the internal pressure of the second auxiliary oil chamber 70 as shown in FIG. 3C, and the enlarged diameter portion 82b of the plunger 82 narrows the plunger hole. Reduce its flow path area. Therefore, the flow of oil that passes through the restriction between the enlarged diameter portion 82b and the plunger hole flows through the orifice 72, and the differential pressure generated on both sides of the orifice 72 due to this flowing water slightly pushes down the switching valve 66. Since this amount of depression is small, a sufficiently large damping force can be generated.

Next, the control device 34 will be explained based on FIGS. 2 and 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
The piston position X and the output voltage of the potentiometer 26 are not proportional.

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

Reference numeral 102 denotes a piston speed calculating means, which calculates, for example, the piston speed (2) by time differentiation of the piston position (X). 10
Reference numeral 4 denotes a memory means composed of a semiconductor memory such as a ROM. For example, as shown in FIG. 4, this memory means 104 stores a map that determines the optimum damping force F as a function of piston position X and piston speed V for compression (FIG. 4A) and expansion (FIG. 4B). It is something to remember. 4th A
The three-dimensional damping characteristics shown in Figure 4B can be changed depending on the vehicle type, driving conditions, etc., and various characteristics that cannot be obtained with conventional orifice control, such as the characteristic that the damping force decreases as the piston speed X increases, can be changed. It is also possible to store the characteristics in advance and select and use preferred characteristics according to the driving conditions. Note that 106 is 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 piston speed V 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.
Zero thrust 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.

According to this embodiment, by changing the diameter or length of the small diameter portion 82a and the enlarged diameter portion 82b of the plunger 82, it is possible to change the damping force when the excitation current of the linear solenoid 80 is interrupted.

(Effects of the Invention) As described above, the present invention provides an enlarged diameter portion via a small diameter portion at the end of the plunger on the second auxiliary oil chamber side for releasing the internal pressure of the second auxiliary oil chamber to the low pressure side main oil chamber. Since the plunger is connected in series, the linear solenoid that pushes this plunger toward the second auxiliary oil chamber is
If the t-flow is interrupted for some reason, the enlarged diameter portion narrows the plunger hole and increases the flow path resistance, making it possible to continue generating sufficient damping force. Therefore, even if this excitation current is cut off during running, it is possible to continue running stably.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of a main part of an embodiment of the present invention, Fig. 2 is a conceptual diagram and functional block diagram during use, Figs. 3A to 30 are explanatory diagrams of operation, and Figs. 4A and 4B are respectively FIG. 4 is a diagram of attenuation characteristics during compression and expansion. 18... Attenuator, 26... Potentiometer, 52... Piston, 54.56... Main oil chamber, 6
6...Switching valve, 68.70...First and second auxiliary oil chambers 72...Orifice, 82...Plunger, 82a...Small diameter portion, 82b...Enlarged diameter portion. Patent applicant Yamaha Motor Co., Ltd.

Claims (1)

[Claims] There is a first oil chamber in the piston defining two main oil chambers in the cylinder.
・The switching valve defining the second auxiliary oil chamber, the orifice interposed between the two auxiliary oil chambers, and the pressure in the second auxiliary oil chamber move the linear solenoid toward the low-pressure main oil chamber against the set pressure. and a plunger for reducing the pressure in the second auxiliary oil chamber, while guiding the hydraulic pressure in the high-pressure side main oil chamber to the first auxiliary oil chamber;
In the damper, the pressure in the auxiliary oil chamber is reduced by the movement of the plunger, thereby moving the switching valve to open an oil passage between the two main oil chambers and controlling the damping force, wherein the plunger has a tip end side thereof. An enlarged diameter part is connected to the linear solenoid via a small diameter part, and the enlarged diameter part restricts the outflow of oil from the second auxiliary oil chamber when the excitation current of the linear solenoid is cut off. Attenuator.