JPH05149364A - Damping force adjustable hydraulic shock absorber - Google Patents

Abstract

(57) [Abstract] [Purpose] The damping force characteristic of the damping force adjusting type hydraulic shock absorber is made to be a hard characteristic without energization, a small current is made to be a soft characteristic, and the damping force is increased in proportion to the current. [Structure] A piston 3 is fitted in a cylinder 2 in which an oil liquid is sealed. Main oil liquid passages 7 and 8 (large damping force) and a bypass passage 12 (small damping force) that connect the cylinder upper chamber 2a and the lower chamber 2b are provided. The bypass passage 12 is provided with a guide member having an opening 16 and a shutter 17 having a groove 18,
A spring 22 for urging 17 downward is provided. A proportional solenoid actuator 24 is connected to the shutter 17. Solenoid 26
When the power is not applied to the
The shutter 17 is displaced upward when a small current is applied, and the groove 18 is aligned with the opening 16 to provide a soft characteristic when a small current is applied.When the current is increased, the shutter 17 is displaced upward in proportion to the current. The area of the passage between the opening 16 and the groove 18 is reduced, and the shutter 17 closes the opening 16 to provide a hard characteristic.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a damping force adjustable hydraulic shock absorber used in a suspension system of a vehicle such as an automobile.

[0002]

2. Description of the Related Art In a hydraulic shock absorber used for a suspension system of a vehicle such as an automobile, a damping force can be appropriately adjusted in order to improve riding comfort and steering stability in accordance with road conditions, running conditions and the like. There is a damping force adjustable hydraulic shock absorber.

As this type of hydraulic shock absorber, for example, as disclosed in Japanese Utility Model Publication No. 59-22359 and Japanese Utility Model Publication No. 60-37477, two partitioned chambers are communicated with each other through a plurality of passages. A damping force generating mechanism (for example, an orifice or a disc valve) that controls the flow of the oil liquid generated in the passage due to the sliding of the piston in the cylinder to generate the damping force is provided, and one of the passages is connected to a solenoid valve. There is a type in which the damping force can be adjusted by selectively opening and closing. The solenoid valve for opening and closing the passage is configured to open the passage by energizing the solenoid that energizes the valve body that is urged by a coil spring or the like to shut off the passage.

When the damping force characteristic of the hydraulic shock absorber is controlled according to the running condition of the vehicle, the road surface condition, etc., generally, when the vehicle is normally running, the softness of the damping force is small so that the ride comfort is improved and the vehicle is started. When braking, turning, traveling at high speed, etc., the steering stability is improved as a hard characteristic with a large damping force. Therefore, in a general vehicle usage condition, the soft characteristic is set more often than the hardware characteristic, and the total setting time is long.

However, in the conventional damping force adjusting type hydraulic shock absorber described above, when the solenoid is not energized, the coil spring closes the passage so that the valve element has a hard characteristic and has a soft characteristic while energized. If the setting time is long, there is a problem that power consumption increases.

On the other hand, in contrast to the above-mentioned conventional example, the solenoid valve for opening and closing the passage is constructed so that the valve body is biased by the spring in the valve opening direction, so that the solenoid valve has a soft characteristic without being energized. , There are those that are designed to have a hard characteristic while energized. According to this configuration, the energization time can be shortened and the power consumption can be reduced in a general vehicle usage situation where the soft characteristic setting time is long.

[0007]

By the way, in the damping force adjusting type hydraulic shock absorber as described above, when the solenoid cannot be energized due to a disconnection or the like, in order to ensure good steering stability, the hydraulic shock absorber It is desirable that the damping force characteristic is fixed to the hard characteristic side.

However, the conventional solenoid having a soft characteristic without energization has a problem that the damping force characteristic is fixed to the soft characteristic when the solenoid cannot be energized.

The present invention has been made in view of the above points, and the damping force characteristic becomes a hard characteristic when not energized, and the damping force adjusting hydraulic buffer which consumes less power in a general use condition. The purpose is to provide a container.

[0010]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention uses a sliding piston in a cylinder to
By controlling the flow of the oil liquid generated in the oil liquid passage communicating between the two chambers to generate a damping force, and by adjusting the passage area of the bypass passage communicating between the two chambers by the damping force adjusting valve. In the damping force adjusting hydraulic shock absorber capable of adjusting the damping force, the damping force adjusting valve includes a guide member and a shutter having openings that can be aligned with each other. It is possible to move from one hard characteristic position through the middle soft characteristic position across the opening of the guide member to the other hard characteristic position, and further urge the shutter toward the one hard characteristic position side. A spring and a proportional solenoid actuator that displaces the valve body against the biasing force of the spring are provided.

[0011]

With this configuration, in the damping force adjusting valve, when the solenoid is not energized, the opening of the shutter is located at one of the hard characteristic positions of the guide member due to the biasing force of the spring, and when the solenoid is energized, the shutter is opened. When the displacement is caused and the opening and the opening of the guide member are aligned to reach the soft characteristic position and the energizing current is further increased, the shutter is displaced in proportion to the current, and the opening is the other of the openings of the guide member. Move to the hard characteristic position of. Therefore, the damping force characteristic is a hard characteristic when the solenoid is not energized.
When energized, it has a soft characteristic, and when the energized current increases, the damping force increases in proportion to the current, resulting in a hard characteristic.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. Note that, in FIG. 1, the right side of the paper surface shown in (a) shows the state of the hardware characteristic (the state where the solenoid is not energized), and the left side of the paper surface shown in (b) shows the state of the soft characteristic, and in FIG. , (C) on the right side of the paper shows the state of medium characteristics, and (d) on the left side of the paper shows the state of hard characteristics.

As shown in FIG. 1, in a hydraulic shock absorber 1, a piston 3 is slidably fitted in a cylinder 2 in which an oil liquid is sealed, and the inside of the cylinder 2 is cylinder upper chamber 2a by the piston 3. And a cylinder lower chamber 2b. A cylindrical passage member 4 having a flange portion 4a formed at one end side is inserted into the piston 3, and a cylindrical large-diameter passage member 5 is screwed and fixed at the other end side. One end of a piston rod 6 is screwed to the flange portion 4a of the small diameter passage member 4, and the other end of the piston rod 6 extends to the outside of the cylinder 2.

The piston 3 is provided with main oil liquid passages 7 and 8 for connecting the cylinder upper chamber 2a and the cylinder lower chamber 2b. On the end surface of the piston 3 on the cylinder upper chamber 2a side, a damping force generating mechanism 9 including a disc valve and an orifice for controlling the flow of the oil liquid in the main oil passage 7 to generate a damping force is provided. At the end surface of the piston 3 on the cylinder lower chamber 2b side, a damping force generation mechanism 10 including a disc valve and an orifice for controlling the flow of the oil liquid in the main oil liquid passage 8 to generate a damping force is provided.

The piston rod 6 is provided with an oil liquid passage 11 having one end communicating with the inside of the small diameter passage member 4 and the other end opening to the side wall of the piston rod 6, the small diameter passage member 4 and the large diameter passage. The member 5 and the oil liquid passage 11 constitute a bypass passage 12 that connects the cylinder upper chamber 2a and the cylinder lower chamber 2b.

In the large-diameter passage member 5, a damping force generating member composed of an orifice and a disk valve for controlling the flow of the oil liquid from the cylinder upper chamber 2a side to the cylinder lower chamber 2b side of the bypass passage 12 to generate the damping force is generated. A mechanism 13 and a check valve mechanism 14 that allows the flow of oil liquid from the cylinder lower chamber 2b side to the cylinder upper chamber 2a are provided. The damping force generation mechanism 13 is
Damping force generation mechanism 9, 10 for main oil passages 7, 8 of piston 3
Flow resistance (damping force) is set smaller than that.

Inside the oil liquid passage 11 of the piston rod 6, there is provided a cylindrical guide member 15 which divides the oil liquid passage 11 into a cylinder upper chamber 2a side and a cylinder lower chamber 2b side. The chamber 2a side and the cylinder lower chamber 2b side are communicated with each other through an opening 16 provided in a side wall of the guide member 15. As shown in FIG. 3, the shape of the opening 16 is such that the opening area of the lower part is large and the opening area becomes smaller toward the upper part. In the guide member 15, a bottomed cylindrical shutter 17 is slidably fitted. An annular groove 18 is provided as an opening along the outer periphery of the shutter 17, and an oil passage 19 penetrating the side wall of the guide member 15 is provided in the groove 18. Further, the shutter 17 has
An oil liquid passage 20 is provided which penetrates the bottom portion. The guide member 15 and the shutter 17 constitute a damping force adjusting valve, and the opening 16 of the guide member 15 and the groove of the shutter 17 are formed.
Cylinder upper chamber 2a in liquid passage 11 due to alignment with 18
Side and the cylinder lower chamber 2b side are communicated with each other, and the cylinder upper chamber 2a and the cylinder lower chamber 2b are communicated with each other by the bypass passage 12. The bypass passage 12 has a shutter 17
As the groove 18 slides, the groove 18 has a lower hardware characteristic position (a) (see FIGS. 1 and 3) and an upper hardware characteristic position (d) (see FIGS. 2 and 3) across the opening 16. It is designed to move between the two and communicate with each other in a passage area corresponding to the position. In FIGS. 1 and 2, reference numeral 21 is a support member for fixing the guide member 15.

Between the shutter 17 and the support member 21, a spring 22 for urging the shutter 17 toward the lower hardware characteristic position (a) side.
Is provided. One end of a rod 23 is connected to the bottom of the shutter 17, and the other end of the rod 23 is slidably inserted into the support member 21 and extends along the axial center of the piston rod 6, and is built in the piston rod 6. Is connected to the plunger 25 of the proportional solenoid actuator 24. By energizing the solenoid 26 of the proportional solenoid actuator 24, the solenoid 26 attracts the plunger 25 and moves it upward, and the shutter 17 moves upward against the elastic force of the spring 22. ..

The proportional solenoid actuator 24 generates a suction force proportional to the current supplied to the solenoid 26, and the shutter is moved to a position where the suction force and the elastic force of the spring 22 are balanced.
It is designed to displace 17. And solenoid
When the energizing current to 26 is a predetermined small current, the shutter 17 is displaced to the soft characteristic position (b) and the passage area between the opening 16 and the groove 18 is maximized. The shutter 17 is displaced upward to reduce the passage area (see FIGS. 2 and 3 (c)), and the shutter is closed (see FIG. 2).
And (d) of FIG. 3). In the figure, 27 is a base plunger and 28 is a lead wire for energizing the solenoid 26.

The characteristics of the proportional solenoid actuator 24 and the spring 22 are shown in FIG. In FIG. 4, I ₁ , I ₂ , I
₃ , the shutter 17 is located at the positions (b), (c),
The relationship between the displacement of the shutter and the attraction force of the solenoid when a current required for displacement to (d) is applied is shown as B
Shows the relationship between the displacement of the shutter 17 and the elastic force of the spring 22. Further, A is a range in which the attraction force of the solenoid is proportional to the energizing current, that is, the range in which the displacement of the shutter 17 is proportional to the current is limited due to the structure of the solenoid, and A indicates the proportional range.

The operation of this embodiment having the above-mentioned structure will be described below.

When the solenoid 26 is not energized, the shutter is
17 is in the lower hard characteristic position (a) shown in FIGS. 1 and 3 due to the elastic force of the spring 22, and the bypass passage 12 is closed. Therefore, as the piston 3 slides due to the expansion and contraction of the piston rod 6, the oil liquid in the cylinder 2 flows through the main oil liquid passages 8 and 9 and the damping force generating mechanisms 9 and 10 are generated.
Causes a relatively large damping force. Therefore, the damping force characteristic becomes a hard characteristic.

When a predetermined small current is applied to the solenoid 26, the suction force of the proportional solenoid actuator 24 causes the shutter 17 to move to the soft characteristic position (b) shown in FIGS.
And the bypass passage 12 opens. At this time, the opening 16
And the groove 18 are aligned to maximize the passage area, and as the piston 3 slides due to the expansion and contraction of the piston rod 6, the oil liquid in the cylinder 2 flows through the bypass passage 12 and the damping force generation mechanism 13 is used during the extension stroke. Check valve mechanism during distribution and compression stroke
Circulates 14 to generate a relatively small damping force. Therefore,
The damping force characteristic becomes a soft characteristic.

When the energizing current to the solenoid 26 is further increased, the suction force of the proportional solenoid actuator 24 causes the shutter 17 to move further upward as shown in the position (c) of FIGS. 2 and 3, and is proportional to the energizing current. As a result, the passage area of the bypass passage 12 continuously decreases. Therefore, as the piston 3 slides due to the expansion and contraction of the piston rod 6, the oil liquid in the cylinder 2 flows through the bypass passage 12 and the damping force generating mechanism 13 during the extension stroke, and the check valve mechanism during the contraction stroke. 14 to generate a greater damping force than when the shutter 17 is at the position (b). Therefore, the damping force characteristic is a medium characteristic intermediate between the soft characteristic and the hard characteristic.

When the energizing current to the solenoid 26 is further increased, the suction force of the proportional solenoid actuator 24 causes the shutter 17 to move further upward, and thus the shutter 17 is moved upward.
The bypass passage 12 is closed by displacement to the upper hard characteristic position (d) shown in FIG. Therefore, as in the case where the solenoid 26 is not energized, the oil liquid in the cylinder 2 flows through the main oil liquid passages 8 and 9 as the piston 3 slides due to the expansion and contraction of the piston rod 6 and the damping force generating mechanisms 9 and 10. Causes a relatively large damping force. Therefore, the damping force characteristic becomes a hard characteristic.

As described above, when the energizing current to the solenoid 26 is zero, the hardware characteristic, the soft characteristic when the predetermined small current is applied, and the damping force which is generated in proportion to the current when the predetermined small current is exceeded is continuous. It becomes a large and hard characteristic.

Therefore, in the case of soft characteristics that are frequently used in general vehicle usage, a small current can be applied so that the power consumption is small, and when the current cannot be applied due to a disconnection or the like, the hardware characteristics are good. It is possible to ensure good steering stability.

In the present embodiment, the opening 16 has a shape as shown in FIG. 3, but the shape is not limited to this, and any other shape can be used as long as the passage area changes similarly according to the displacement of the shutter 17. It may have a shape.

Further, in this embodiment, the communication between the opening 16 and the groove 18 is cut off at both the hard characteristic positions (a) and (d) sandwiching the opening 16, and the bypass passage 12 is completely closed. However, the present invention is not limited to this, but at the hardware characteristic positions (a) and (d), the opening 16 and the groove 18 partially communicate with each other, and a small amount of oil liquid flows from the bypass passage 12. The state to be performed may be set as a hardware characteristic. Moreover, the damping force characteristics of the lower hard characteristic position (a) and the upper hard characteristic position (d) do not necessarily have to be the same, and if the damping force is larger than the intermediate soft characteristic, different damping characteristics are obtained. You may make it have a force characteristic.

[0030]

As described above in detail, according to the damping force adjusting type hydraulic shock absorber of the present invention, the damping force adjusting valve is composed of the guide member and the shutter each having an opening which can be aligned with each other. , The shutter is movable from one hard characteristic position through the middle soft characteristic position with the opening sandwiching the opening of the guide member to the other hard characteristic position. Since a spring for biasing the side and a proportional solenoid actuator for displacing the shutter against the biasing force of the spring are provided,
The damping force characteristic is a hard characteristic when the solenoid is not energized, becomes a soft characteristic when energized, and when the energized current is further increased, the damping force is continuously increased in proportion to the current and becomes a hard characteristic. As a result, it is possible to have a soft characteristic by energizing a small current, so it is possible to reduce the power consumption in the general usage condition of the vehicle, and in the case where the energization becomes impossible due to a disconnection, etc. It has an excellent effect of being able to secure good steering stability.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a state in which a hard characteristic (zero shutter displacement) and a soft characteristic are set in an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view showing a state where medium characteristics and hard characteristics are set in an embodiment of the present invention.

FIG. 3 is an explanatory view showing a passage area of a shutter and an opening of a guide member of the damping force adjusting valve of the apparatus of FIGS. 1 and 2.

FIG. 4 is a diagram showing the relationship between the displacement of the shutter of the damping force control valve of the apparatus of FIGS. 1 and 2 and the elastic force of the spring and the attraction force with respect to the energizing current of the proportional solenoid actuator.

[Explanation of symbols]

 1 Damping force adjustable hydraulic shock absorber 2 Cylinder 2a Cylinder upper chamber 2b Cylinder lower chamber 3 Piston 8,9 Main oil liquid passage 12 Bypass passage 15 Guide member 16 Opening 17 Shutter 18 Groove (opening) 22 Spring 24 Proportional solenoid actuator

Claims (1)

[Claims] 1. A bypass passage communicating between the two chambers by controlling a flow of the oil liquid generated in an oil passage communicating between the two chambers by sliding a piston in the cylinder to generate a damping force. In a damping force adjusting hydraulic shock absorber in which the damping force can be adjusted by adjusting the passage area of the damping force adjusting valve by means of a damping force adjusting valve, each of the damping force adjusting valves has a guide member having an opening part that can be aligned with each other. And a shutter, and the shutter is movable from one hard characteristic position through the middle soft characteristic position with the opening portion sandwiching the opening of the guide member to the other hard characteristic position. A reduction device characterized in that a spring for urging the shutter toward the one hardware characteristic position side and a proportional solenoid actuator for displacing the valve body against the urging force of the spring are provided. Damping force adjustable hydraulic shock absorber.