JPH05180261A - Variable damping force type damper - Google Patents

Abstract

PURPOSE:To adjust damping force of a damper of large capacity by a small solenoid valve. CONSTITUTION:A poppet 17 to open and close in accordance with flowing pressure of operating oil is provided in a passage to flow the operating oil in accordance with telescopic motion of a damper main body 1. Thereafter, the poppet 17 is energized in the shut-off direction by a spring 18. An orifice 19 one end of which is opened to the upstream of the poppet 17 and the other end of which is opened to a back pressure cell 22 shut-off from the passage 13 and an alternate passage 20 to connect the back pressure cell 22 to the passage 13 on the downstream side of the poppet 17 are provided. A solenoid comparative pressure control valve 21 to control pressure of this back pressure cell 22 in accordance with an input signal is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a damping force variable damper for controlling a generated damping force according to a signal.

[0002]

2. Description of the Related Art As a damping force variable damper for controlling a generated damping force according to a signal, for example, a solenoid valve is provided in a passage through which hydraulic oil flows as the damper expands and contracts, and responds to a signal sent from the outside. It is known that the solenoid valve changes the flow resistance in the passage to change the generated damping force.

[0003]

In such a damper, since the entire amount of hydraulic oil flowing through the damper passes through the solenoid valve, it is necessary to use a large solenoid valve for a damper having a large capacity, and the damper becomes larger. Therefore, it is inevitable that the solenoid valve will become larger and the cost will increase accordingly.

The present invention has been made to solve the above problems, and an object thereof is to adjust the damping force of a large-capacity damper by using a small solenoid valve.

[0005]

SUMMARY OF THE INVENTION According to the present invention, there is provided a passage through which hydraulic oil flows according to expansion and contraction of a damper main body, a poppet that opens and closes this passage according to circulating pressure of hydraulic oil, and a poppet in a closing direction. A biasing spring, an orifice that connects the poppet upstream side of the passage with a back pressure chamber that exerts a back pressure on the poppet, a bypass passage that connects the back pressure chamber to the poppet downstream side of the passage, and the pressure of the back pressure chamber. And an electromagnetic proportional pressure control valve for controlling the control signal according to an input signal.

[0006]

[Operation] When the flow rate of the hydraulic oil is small, the hydraulic oil flows through the bypass passage through the orifice and the electromagnetic proportional pressure control valve, and the damper generates a damping force corresponding to the control pressure of the electromagnetic proportional pressure control valve. Let

When the flow rate in the bypass passage increases, the pressure difference before and after the orifice rises, the pressure difference lifts the poppet against the spring, and the hydraulic oil flows through the passage opened by the poppet. In this case, the damping force generated by the damper changes according to the lift amount of the poppet, but this lift amount changes according to the back pressure acting on the poppet, and the back pressure becomes the control pressure of the electromagnetic proportional pressure control valve. Change accordingly. That is, also in this case, the damping force generated by the damper changes in accordance with the control pressure of the electromagnetic proportional pressure control valve, so that the damping force generated by the large capacity damper can be controlled using the small flow rate electromagnetic proportional pressure control valve.

[0008]

1 and 2 show an embodiment of the present invention.

In FIG. 1, reference numeral 1 is a damper body, in which a piston 3 is slidably housed in a cylinder 2 and
A piston rod 4 connected to the cylinder 1 projects axially from the cylinder 1.

The interior of the cylinder 1 is defined by a piston 3 into an oil chamber 5 on the piston rod 4 side and an oil chamber 6 on the opposite side.

The piston 3 is provided with a check valve 7 which allows only the flow of hydraulic oil from the oil chamber 6 to the oil chamber 5. Further, an outer tube 8 is coaxially provided outside the cylinder 1, and an oil reservoir chamber 9 in which air is sealed above the oil surface is provided in an annular gap between the outer tube 8 and the cylinder 1 to compensate for fluctuations in the amount of oil in the cylinder 1. Be done. The oil chamber 9 to the oil chamber 6 are provided at the bottom of the cylinder 1.
A check valve 10 is provided that allows only the flow of hydraulic oil to and from it.

On the other hand, the oil chamber 5 is connected to the oil reservoir 9 via a passage 13 having a logic valve 12.

Details of the logic valve 12 are shown in FIG.
The logic valve 12 is such that a port 15 communicating with the oil chamber 5 is formed in a casing 14 attached to the tip of the cylinder 1, and a poppet 17 is seated on a seat 16 formed in the port 15, and a passage 13 is provided on the side of the poppet 17. Opens. The hydraulic oil in the oil chamber 5 flows into the oil sump chamber 9 via the port 15 and the passage 13 which are communicated by the lift of the poppet 17.

The poppet 17 is biased toward the seat 16 by a spring 18. An orifice 19 is formed at the tip of the poppet 17. This orifice 19
Communicates the oil chamber 5 and a back pressure chamber 22 formed behind the poppet 16 so as to be blocked from the passage 13, and exerts a back pressure on the poppet 17.

The back pressure chamber 22 has an electromagnetic proportional pressure control valve 2 in the middle thereof.
It is connected to the passage 13 on the downstream side of the poppet 17 via the bypass passage 20 provided with 1. The electromagnetic proportional pressure control valve 21 is a valve that controls the pressure in the back pressure chamber 22 to a pressure proportional to the input signal.

In this damper, the operation of which will be described below, the hydraulic oil flows from the oil chamber 5 to the oil reservoir 9 regardless of whether the piston 3 is extended or contracted.

The poppet 17 of the logic valve 12 is acted on by the pressure of the oil chamber 5, the back pressure of the back pressure chamber 22 and the pressure of the spring 7 which oppose it, and lifts according to the balance of these forces. .. That is, a pressure difference corresponding to the pressure loss of the working oil flowing through the orifice 19 is generated between the pressure of the oil chamber 5 and the back pressure of the back pressure chamber 22, and this pressure difference increases the flow rate of the orifice 19 to cause the spring 7 The poppet 17 is lifted when the valve closing force is exceeded.

Therefore, when the piston 3 slides at a low speed, the poppet 17 does not lift, and the hydraulic oil flowing out from the oil chamber 5 to the oil reservoir 9 passes through the orifice 19 and the electromagnetic proportional pressure control valve 21. It circulates in the bypass passage 20. The electromagnetic proportional pressure control valve 21 controls this outflow pressure in response to the input signal, and the damper generates a damping force according to this outflow pressure. That is, the damping force generated by the damper is directly controlled by the electromagnetic proportional pressure control valve 21.

On the other hand, when the piston 3 slides at a high speed, the flow rate of the orifice 19 increases and the pressure in the oil chamber 5 and the back pressure chamber 2 increase.
The poppet 17 lifts against the spring 7 due to the increase in the pressure difference from the back pressure of 2.

As a result, the hydraulic oil in the oil chamber 5 is the poppet 1
It flows through the periphery of 7 into the passage 13. The damping force generated in this state is determined by the lift amount of the poppet 17, and this lift amount has the following characteristics.

That is, when the control pressure of the electromagnetic proportional pressure control valve 21 is lowered, the flow rate of the orifice 19 increases and the pressure difference between the pressure of the oil chamber 5 and the back pressure of the poppet 17 increases, so that the lift of the poppet 17 is increased. The quantity increases.

On the contrary, when the control pressure of the electromagnetic proportional pressure control valve 21 is increased, the flow rate of the orifice 19 is decreased and the lift amount of the poppet 17 is decreased.

Therefore, even when the poppet 17 is lifted and the hydraulic oil in the oil chamber 5 mainly flows to the passage 13 via the logic valve 12, the damping force generated by the damper is indirectly controlled by the electromagnetic pressure control valve 21. The pressure in the oil chamber 5 is maintained at the pressure obtained by adding the pressure loss of the orifice 19 to the control pressure of the electromagnetic proportional pressure control valve 21.

In this way, the generated damping force of the damper can be arbitrarily changed by the input signal to the electromagnetic pressure control valve 21. Further, even when a large flow rate flows between the oil chamber 5 and the oil reservoir chamber 9, most of the flow rate passes through the logic valve 12 and the flow rate through the electromagnetic pressure control valve 21 is small. Therefore, the electromagnetic proportional pressure control valve 21 may have a small capacity regardless of the capacity of the damper body 1.

[0025]

As described above, according to the present invention, the poppet for opening and closing the passage of the circulating hydraulic fluid according to the expansion and contraction of the damper is provided in accordance with the circulating pressure, and the upstream side of the poppet and the back pressure chamber for exerting a back pressure on the poppet are provided. , And the back pressure chamber was connected to the downstream side of the poppet via the electromagnetic proportional pressure control valve, so the lift amount of the poppet changes according to the control pressure of the electromagnetic proportional pressure control valve, and it depends on the lift amount. A damping force is generated.

Therefore, the generated damping force of the large capacity damper can be controlled using the small flow rate electromagnetic proportional pressure control valve, which has the effect of reducing the manufacturing cost of the damping force variable damper.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a damping force adjustable damper showing an embodiment of the present invention.

FIG. 2 is an enlarged view of the logic valve in FIG.

[Explanation of symbols]

 1 Damper Main Body 12 Logic Valve 13 Passage 17 Poppet 18 Spring 19 Orifice 20 Detour Passage 21 Electromagnetic Proportional Pressure Control Valve 22 Back Pressure Chamber

Claims (1)

[Claims] 1. A passage through which hydraulic oil flows in response to expansion and contraction of a damper body, a poppet that opens and closes this passage according to circulation pressure of hydraulic oil, a spring that biases the poppet in a closing direction, and a passage of the passage. An orifice that connects the upstream side of the poppet and a back pressure chamber that exerts a back pressure on the poppet, a bypass passage that connects the back pressure chamber to the downstream side of the poppet of the passage, and the pressure of the back pressure chamber is controlled according to an input signal. A damping force variable damper comprising an electromagnetic proportional pressure control valve.