JPS58211043A - Hydraulic damper - Google Patents

Abstract

PURPOSE:To simplify a wiring for a solenoid in a solenoid damper valve, by arranging the solenoid damper valve in the bottom of a cylinder. CONSTITUTION:In a dual cylinder type hydraulic damper a pipe 9 for communicating between an upper oil chamber 6 and a lower oil chamber 7, is arranged, longitudinally extending through an oil sump chamber 1 around the outer periphery of a cylinder 2, and a solenoid damper valve 12 whose valve opening pressure proportionally changes in accordance with its energizing current, is arranged in the bottom of the cylinder 2, thereby the damper valve allows hydraulic oil which flows out through the pipe 9 upon extension, to pass therethrough.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic shock absorber whose damping force can be freely adjusted according to operating conditions.

The damping characteristics required of a vehicle's hydraulic shock absorber vary in a variety of ways depending on driving conditions, but ordinary hydraulic shock absorbers can only provide preset fixed characteristics.

Therefore, the present applicant proposed in Japanese Patent Application No. 56-55213 that the opening pressure of the damping valve is increased or decreased by the excitation attraction force of the electromagnetic solenoid, and the damping characteristics are arbitrarily changed according to the external current value. A hydraulic shock absorber was proposed.

However, in this case, since the damping valve installed in the piston is controlled by an electromagnetic solenoid, the wiring for the solenoid coil must pass through the straddle rod, which requires a significant modification to the structure of the straddle rod. Due to the demand, there were many practical problems that needed to be improved, such as durability, ease of assembly, and increased cost.

The present invention was proposed to solve this problem.

Therefore, the present invention provides a double-tube type hydraulic shock absorber with an A-vee that communicates the upper oil chamber and the lower oil chamber, extending vertically through the oil reservoir chamber on the outer periphery of the cylinder, and opening the valve at the bottom of the cylinder according to the excitation current. An electromagnetic damping valve whose valve pressure changes proportionally is provided, and the damping valve is operated on the extension side when the damping valve is operated on the extension side. By passing the hydraulic oil flowing out through the valve, the generated damping force can be arbitrarily adjusted, the wiring for the solenoid of the electromagnetic damping valve is simplified, and there is no need to modify the piston or piston rod.

Embodiments of the present invention will be described below based on the drawings.

A cylinder 2 is arranged concentrically inside the outer cylinder 1, and a piston 3 is housed inside the cylinder 2 so as to be freely slidable, and oil chambers 6 and 7 are defined above and below the piston 3.
An annular oil reservoir chamber 8 is formed between the cylinder 2 and the outer cylinder 1.

The piston head 4 of the piston 3 passes through a bearing 5 in the upper part of the cylinder and projects to the outside.

A check valve 19 is installed in the piston 3, which opens only when the piston is operated on the pressure side to communicate the upper and lower oil chambers 6 and 7.

On the other hand, a pace valve 13 is provided at the bottom of the cylinder 2, and this pace valve 13 has a pace grate 24 attached to the inner circumference of the cylinder 2, and a check valve 21 that opens only when operating on the rebound side, and a check valve 21 that opens only when operating on the compression side. A compression side damping valve 22 that generates damping force by bending is attached.

An electromagnetic damping valve 12 is coaxially disposed below the pace valve 13 and is attached to a support shaft 23 .

The electromagnetic damping valve 12 has a bobbin 15 inserted and fixed to the support shaft 23.
A coil 14 is wound around the coil 14, and a seat portion 16 having a valve port 17 made of a magnetic material is attached to the upper surface of the mebin 15. Lube grate 18 is crimped.

The valve plate 18 is sandwiched between the pace plate 24 and the bobbin 15 and held in close contact with the seat portion 16.

The valve chamber 2 between the pace valve 13 and the electromagnetic damping valve 12
5 communicates with the oil reservoir chamber 8 via a port 20 provided in the cylinder 2.

A vent 10 is provided in the cylinder 2 above the upper oil chamber 6, and a vent 11 is similarly formed in the cylinder 2 located upstream of the electromagnetic damping valve 12 in the lower oil chamber 6. These ports 10 and 11 are connected via a pipe 9 that runs vertically through the interior of the oil reservoir chamber 8.

The lead wire 27 of the coil 14 of the electromagnetic damping valve 12 is inserted into a through hole 26 penetrating the bottom cap 29 of the cylinder 2, and is oil-tightly sealed by a filler 27.

The structure is constructed as described above, and its operation will be explained next. During the pressure side operation in which the piston rod 4 enters the inside of the cylinder 2, hydraulic oil from the lower oil chamber 7 flows into the expanding upper oil chamber 6 via the check valve 19. At the same time, the hydraulic oil corresponding to the intrusion volume of the piston rod 4 expands the pressure side damping valve 22 of the pace valve 13 and flows from the valve chamber 25 into the oil reservoir chamber 8 via the passage 20.

At this time, the electromagnetic damping valve 12, which communicates with the upper oil chamber 6 via t4 and f9, is kept closed.
Hydraulic oil does not flow through the

Therefore, the damping force during compression side operation is generated only by the pace valve 13.

On the other hand, during the expansion side operation in which the piston rod 4 is pulled out, the Dobe oil chamber 6 contracts and the lower oil chamber 7 expands.

Since the pressure side check valve 19 provided on the piston 3 is kept closed, the hydraulic oil in the upper oil chamber 6 flows into the electromagnetic damping valve 12 via the nozzle 4 ignition 9, and the valve port 17 is deflected while the valve grate 18 is bent. Since it flows out into the valve chamber 25, a damping force corresponding to the deflection resistance of the valve grate 18 is generated at this time.

By the way, when the seat portion 16 of the valve plate 18 is magnetized, the resulting attraction force acts in the valve closing direction, so the damping force increases in proportion to the attraction force.

The seat portion 16 is magnetized in proportion to the excitation current applied to the solenoid coil 14, increasing its attractive force, so that the valve opening characteristic ultimately changes in proportion to the solenoid excitation current.

For example, if the excitation current is increased to increase the damping force when the vehicle is running at high speeds, handling stability at high speeds will be improved.
Conversely, by weakening the excitation force when driving at low speeds around town, it is possible to reduce the damping force and improve ride comfort.

For these controls, the excitation current may be optimally controlled by a microcomputer or the like based on signals from sensors that detect operating conditions.

As described above, according to the present invention, the rebound damping force can be freely controlled according to the driving conditions, improving steering stability and ride comfort, while the electromagnetic damping valve is fixed to the lower part of the cylinder.
Wiring to the solenoid coil is easy, the existing piston and piston rod can be used as is, productivity and assemblage are good, and costs are reduced, so it has great practical value.

[Brief explanation of the drawing]

The drawings are cross-sectional views showing embodiments of the present invention. 1... Outer cylinder, 2... Cylinder, 3... Piston,
4... Piston rod, 6, 7... Oil chamber, 8...
Oil sump chamber, 9... Pipe, 10.11... Vent, 12
...Electromagnetic damping valve, 13...Pace valve, 14...
・Solenoid coil, 16... sea) section, 18...
Valve plate, 20...port. Patent applicant Kayaba Kogyo Co., Ltd.

Claims (1)

[Claims] A cylinder is fixed concentrically inside the outer cylinder, a piston is housed in the cylinder so that it can slide freely, an oil chamber is provided on the upper and lower surfaces of the piston inside the cylinder, and an oil reservoir chamber is provided between the outer cylinder and the cylinder. In the double-tube hydraulic shock absorber, the piston is equipped with a check valve that opens only on the pressure side and communicates the upper and lower oil chambers, and a check valve that is located at the bottom of the lower oil chamber and adjusts the opening pressure according to the excitation current. A hydraulic shock absorber characterized in that an electromagnetic damping valve that increases and decreases proportionally is provided, and a nosobib that communicates between the upper oil chamber and the upstream side of the electromagnetic damping valve in the lower oil chamber is arranged vertically through the oil reservoir chamber. .