JPS58221031A - Frequency responsive type shock absorber - Google Patents

Abstract

PURPOSE:To enable a damping force to be changed over by a method wherein a plurality of resonance valves having different proper frequencies are provided together with a change-over valve which selectively opens the port having the resonance valves interposed therein. CONSTITUTION:A plurality of passages 10A to 10D communicating the upper and lower oil chambers 3 and 4 to each other are formed, resonance valves 11A and 11B having mutually different proper frequencies are arranged in these passages 10A to 10D. A changeover valve 17 is also provided to selectively open the passages having the resonance valves 11A and 11B. This change-over valve 17 is operated through an operating rod 21 from outside to perform a change-over operation.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a shock absorber whose damping force changes in a specific frequency range in response to operating conditions.

Japanese Patent Laid-Open No. 2003-1993 (Shokai) published a shock absorber for vehicles that increases or conversely decreases the damping force in a specific vibration frequency range that acts on the vehicle in order to improve handling and ride comfort. No. 55-126139 and JP-A-55-
It is disclosed in Japanese Patent No. 126140.

This causes resonance in a specific vibration frequency range and uses a resonance valve to make the passage that bypasses the damping valve listen only at resonance, or close only at resonance, thereby significantly changing the damping noise in a specific resonance frequency range. It was designed so that
For example, by weakening the damping force in a specific low frequency range (Fig. 1 (Δ
)) absorbs low-frequency vibrations from the car body, preventing unpleasant vibrations from being transmitted to the car body, or increasing the damping force in a specific frequency range (Fig. 1 (B)). ” - to prevent ring and nose dives.

However, as you can see from this, increase the damping force! However, lowering the frequency range is limited to a specific frequency range, so unless the requirements for one area are met, the requirements for other areas cannot be met. There were problems such as no improvement in safety.

In order to solve these problems, the invention provides a switching valve that selectively listens to the baud 1- installed in the resonant valves. This provides a frequency-sensitive shock absorber that can switch the damping force in a vibration frequency range of C5 according to operating conditions.

The embodiments of Komei Ki will be described above based on the drawings.

In Fig. 2 (△) and (B), the cylinder (outer 1
A screw I-on 2 is housed in the 1 so that it can slide freely, and an oil chamber 3 is installed above and below the 1. /I and C respectively.

Screws 1-2 are on the expansion side ('+ Listen at the time of initial operation') 2-part oil chamber 3
/JI Apply a predetermined damping force of 1'J to the hydraulic oil flowing to the bottom oil chamber 4! j 'J Rebound side damping valve 6 (see Fig. 3)
13) shows only a part of the bow 11), and conversely, a pressure side damping valve 7 that opens during pressure side operation and applies a predetermined damping force to the hydraulic oil flowing from the lower oil chamber 4 to the second part oil chamber 3. are arranged.

In parallel with each of these damping valves 6, 7, there are a plurality of boats (passages) IOA, 10B, 10G that connect the upper and lower oil chambers 3, 4 (four in this embodiment C).

10D are formed on the same circumference of the screws 1-2 at symmetrical intervals.

The boats 10A and 10G have resonance valves 11Δ, and the boats 108 and 10D have resonance valves 11Δ that have a different resonance frequency (characteristic frequency) (the set resonance valve 11B
are interposed respectively.

The resonance valves 11Δ and 118 are basically configured the same,
A resonance spool 12 having an annular groove 15 is slidably housed in the spool hole 13, and is held in a neutral state by neutral springs 14Δ and 148 that are in elastic contact with the upper and lower parts of the resonance spool 12. - Fully open 10D.

The natural frequencies of the resonance valves 11Δ and 11B are the mass of the swing spool 12 and the neutral spring 14Δ.

The resonance valve 11Δ (11FB) causes the Jt oscillating stool 12 to resonate when the vibration frequency of the screw 1-hen 2 matches the natural frequency. 10D from fully open to fully closed.

The natural frequency of the Jt swing valves 11Δ, 11B is set to a specific value depending on the operating conditions as described later.

Screw 1-10 A~1 on the bottom surface of screw 1-2
A switching valve 17 is provided to selectively open 0D.

The switching valve 17 is located at a symmetrical position on the outer circumference of the rotating f-isk 18.
1. IJ notches 19 are provided oppositely, and this notch 1
9) baud h 10Δ~10D is released.

In this embodiment C, two bauds i~10A and 10C or 10 [3 and 10D are opened or closed to +15.

In addition, the rotational j isk 18 is equipped with the aforementioned expansion side and compression side reducing Q valves 6.
．． 7 bows 1- to flowering sea urchins, one arc-shaped 1'
; Grooves 20 are arranged concentrically.

An operating rod 21 is concentrically connected to the switching valve 17, and the operating rods 1 to 21 are connected to a screw rod 22.
penetrates in the axial direction and protrudes to the outside.

A rotary solenoid 23 is connected to the tips of the operating rods 1 to 21, and the operating rod 21 can be rotated by a predetermined angle (90'') in response to a drive signal from a control circuit 24.

Note that the rotary solenoid 23 and the piston rod 22 are coupled to the vehicle body side.

The control circuit 24 receives a signal representative of the operating state, such as a vehicle speed signal from the vehicle speed sensor 25 or a cart loading signal from the intermediate stop r1 heavy sensor 26, and based on this, the control circuit 24 rotates the operating rod 21. and selectively open resonance valve 11Δ or bow 1~ of IIB.

Next, to explain the operation, in the state shown in the figure, the switching valve 17
is Bow] -10△, open 10C, Bow 1-108 and 1
0D is closed.

Therefore, the hydraulic oil moving between the upper and lower oil chambers 3 and 4 passes through the two resonance valves 11A as well as the expansion side and compression side damping valves 6.7.

If the resonance point of the resonance valve 11A with respect to the vibration frequency of the piston 2 is set to, for example, 1°5 to 2°11, which corresponds to the sprung mass vibration during rolling during high-speed traveling and touring, for example, While driving, the control circuit 24 switches the switching valve 17
Keep it in the state shown.

The resonance spool 12 of the resonance valve 11A causes a resonance effect when the vehicle body leans left and right during high-speed cornering.

In other words, the natural frequency of the resonance valve 11△ and the rolling vibration frequency of the vehicle body match, and accordingly, the bis]hen 2 or the same -
When the main body moves Y, the resonant spool 12 has a large amplitude and closes the boats 10Δ and 10G.

As a result, the hydraulic oil passes only through the expansion side and compression side damping valves 6.7, and by setting the damping force of these damping valves 6.7 to be large in advance, the flow of hydraulic oil can be increased. By increasing the resistance, you can prevent the vehicle from tilting.

Therefore, the unsprung vibration received from the road surface while driving at high speeds is
Normally, it is 12 to 151-12, but for this vibration, the resonance valve 11Δ does not resonate and the boat 10Δ.

Since 10C is held fully open, the generated damping force does not increase, and road vibrations are absorbed, resulting in good easterly riding comfort.

In addition, when the vehicle weight changes (changes due to loaded weight), for example when loading the vehicle, in order to increase the damping force and prevent bottoming out, it is necessary to set a resonance point that corresponds to the vibration frequency range that causes bottoming out. When the natural frequency of the resonance valve 11B is set so as to hold the d3G node, the control circuit 24 senses the change in the load and operates it via the rotary solenoid 23.
By rotating the parts 1 to 21, the notch 19 of the switching valve 7 listens to the boats 10B and 10D.

Therefore, in this state, the hydraulic oil flows through the resonance valve 11B, so when bottoming out is likely to occur, the resonance valve 11B resonates and becomes fully open, greatly increasing the damping force.

This significantly restricts the movement of the screws 1 to 2, suppresses the expansion and contraction of the piston rod 22, and prevents bottoming out.

This J: sea urchin C1 operating condition (attenuation in different frequency ranges due to !1, etc.) can be increased, improving ride comfort and improving steering stability.

Next, the embodiment shown in FIG. 3 prevents the dynamic pressure of hydraulic oil from being applied directly to the switching valve 17, thereby improving its operability.

For this reason, the screw 1 screwed onto the tip of the piston rod 22
A pressure chamber 32 is formed inside each of the nuts 1 to 30, and the pressure chamber 32 is connected to the fork 10 through a communication passage 31, and the pressure chamber 32 is connected to the screw 1 to the nut 30 by a communication passage passing through the side wall of the nut 30. It communicates with the lower oil chamber 4 through the hole 33.

The rotary disk 18 of the switching valve 17 is located inside the pressure chamber 32 and is connected to the operating rod 21 passing through the screw 1 and the rod 22 so as to stop the opening end of the communicating path 31. .

(In this case, from the lower oil chamber 4 to the lower oil chamber 3
When the hydraulic oil flows, the direction of the flow is smoothed in the pressure chamber 32, so the movement 11 is not directly applied to the rotating disk 1B, and the contact pressure of the rotating disk 18 is reduced, so that the switching rotation is smoothed. Is it always yen? ) 1.

In this embodiment, the resonance valve 11 is of a normally open type, that is, the boat 10 is closed except for resonance 04.

For this purpose, the annular groove 15 on the outer periphery of the central portion of the resonant spool 12 is removed so that the boat 10 that opens into the spool 7L13 when it resonates opens away from the upper and lower ends of the resonant spool 12.

Note that a through hole 35 is formed inside the resonant spool 12 and passes through the upper and lower chambers, so that the hydraulic oil can freely flow between the upper and lower chambers 36 and 37.

In this case, the damping force increases at frequencies other than the resonance frequency, and the damping force decreases in the resonance region.

Even under the same road surface conditions, the vibration frequency from the bottom of the vehicle changes depending on the vehicle speed; in other words, as the vehicle speed increases, the frequency increases.

Therefore, if you want to improve the ride comfort by 11 points, for example, set the natural frequency of the resonance valve 11 that has resonance points at low, medium, and high speeds, and then adjust the switching valve 17 according to the vehicle speed. Resonant valve 1 that can be switched and rotated to correspond to the situation.
If 1 is selectively communicated, the valves will open in resonance with the unsprung vibrations from low to high speeds, and the damping force can be kept very soft.

In addition to C1, the resonance valve 11 closes all the time in response to vibration frequencies such as rolling and bouncing that would impair steering performance, so these phenomena can be avoided by increasing the damping force. It is.

In this way, the resonance valve 11 may be either a normally open type or a normally closed type depending on the conditions.

d3, this embodiment discloses an example in which well-known γ isk valve type damping valves are used as the expansion side and compression side damping valves 6. It branches from the middle of bow 1- of valve 6.7 to form -C.

The number of swing valves 11 can be freely increased or decreased depending on the situation.
Further, it goes without saying that the switching valve 17 may be configured to listen to each boat 10 one by one.

According to the present invention, a plurality of sliding passages 1-) are formed that communicate the upper and lower oil chambers, and resonant valves having different resonance frequencies are installed in these passages. The resonant valve is equipped with a switching valve that selectively opens the resonant passage, and this switching valve is operated from the outside via an operating rod, so that the resonant valve can be fully opened or fully opened at different frequencies depending on the operating conditions. It can be fully closed, and as a result, the damping force can be suddenly increased or decreased in the resonance region, effectively improving vehicle handling and ride comfort over a wider driving range.

[Brief explanation of the drawing]

FIGS. 1A and 1B are explanatory diagrams showing changes in attenuation characteristics of a conventional device based on the relationship with frequency. Fig. 2 (A>) is a longitudinal sectional view of the first embodiment of the present invention, Fig. 2 (B) is a bottom view of the piston, and Fig. 3 is a longitudinal sectional view of the second embodiment. 1.・Cylinder, 2... Piston, 3.4... Oil chamber, 6゜7... Damping valve, 10.10Δ~101]...
・Boe 1- (passage), 11, 11Δ, 11B... Resonance valve, 12... Resonance spool, 1'lA, 14B...
Neutral spring, 17... Switching valve, 18... Rotating disk, 19... Notch, 21... Operation lot,
22... Piston rod 1-123... Rotary solenoid, 24... Control circuit, 25,' 26...
Sen1no. Patent applicant Kayaba Kogyo Co., Ltd.

Claims (1)

[Claims] A bis I-on is slidably housed in a syringe.
An oil chamber is defined in the upper part of the piston, and a plurality of passages are formed in the piston that communicate with the upper and lower chambers, and a resonant valve that fully opens or completely closes the passages when it resonates with the bis]hen vibration frequency is installed in these passages. are installed respectively, and the vibration frequencies of these Jt swing valves are set differently, while a switching valve that selectively opens these passages is provided on the screw 1, and this switching valve is connected to the screw 1. A frequency-sensitive shock absorber that is characterized by being interlocked with an operating rod that is driven from the outside through the tube.