JPS63180742A - Damping force variable shock absorber device - Google Patents

Abstract

PURPOSE:To simplify the structure of the captioned device resulting in cost reduction and to facilitate elaborate and broad control by a method wherein, in a magnetic fluid which exchangingly flows in a passage accompanied with the extension and contraction of a shock absorber, the viscosity thereof is changed through a magnetic field generated by a damping variable means, thereby the damping force is generated according to the viscosity. CONSTITUTION:With the extension and contraction of a shock absorber A due to the unspring vibration of a vehicle, the exchange of a flow in a magnetic fluid F is generated in a passage provided with a damping force variable means 60. In the magnetic fluid F, the viscosity thereof is changed with the magnetic field generated by a damping force variable means so that the damping force is generated according to the viscosity. Accordingly, the damping force variable means 60 is operated in such a way that the larger vibration is, the larger damping force comes while the vibration energy in a damping force control means C accompanied with unspring vibration is made as a driving source.Therefore, a harness for connecting an external driving source and the like to a damping force variable means 60 is unnecessary, thereby it is possible to simplify the structure and the cost reduction, and then the damping force is changed according to the unspring vibration resulting in the elaborate and broad control so as to improve the controllability and travel stability.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a variable damping force shock absorber device.

(Prior Art) As a conventional variable damping force shock absorber device, for example, one described in Japanese Utility Model Application Publication No. 196444/1983 is known.

In this conventional variable damping force shock absorber device, the cylinder tube of the shock absorber is divided by Vinton into an upper liquid chamber and a lower liquid chamber, and the piston operates during the extension stroke and compression stroke to generate damping force. A damping valve and a damping force variable means operated by an external damping force control means to adjust the damping force of the damping valve were provided.

Further, the damping force control means is composed of an actuator that operates the damping force variable means, a switch or controller that controls the drive of the actuator, and a battery that is the drive source of the actuator. The actuator was connected to the battery, switch, and controller by a harness.

Therefore, this device was able to obtain a damping force that corresponds to the driving conditions of the vehicle based on the operation of the switch or controller.

(Problems to be Solved by the Invention) However, such conventional variable damping force shock absorber devices have the following problems.

■ A harness is required to connect the actuator inside the shock absorber to the battery, switch, and controller outside the shock absorber, and if this harness is routed, the reliability of the connection becomes a problem. Furthermore, the structure becomes complicated due to the routing and connection of the harness, leading to increased costs.

■ Since a battery is required as a drive source, in response to the increase in electrical components in recent vehicles, it is necessary to consider the battery capacity and alternator power generation capacity to prevent battery drain, which reduces the degree of design freedom. Furthermore, using a battery as a driving source consumes engine power, so energy is not used effectively.

(Means for Solving the Problems) The present invention has been made for the purpose of solving the conventional problems as described above, and in order to achieve this purpose, the variable damping force shock absorber device of the present invention has been developed. , a shock absorber having a cylinder tube, a piston, a piston rod, and an outer cylinder; a magnetic fluid filled in a liquid chamber of the shock absorber;
a damping force variable means that is provided in a flow path through which the magnetic fluid displaces and flows during the compression side stroke operation and changes the damping force by changing the viscosity of the magnetic fluid in the flow path by a magnetic field; and a damping force variable means that is built in the unsprung portion of the shock absorber. and a damping force control means for inputting unsprung vibration and outputting a magnetic field generation signal corresponding to the strength of the vibration to the damping force variable means.

(Function) The operation of the variable damping force shock absorber device of the present invention will be explained.

When the unsprung portion of the vehicle vibrates and the vibration is input to the damping force control means provided in the unsprung portion of the shock absorber, the vibration energy generates a magnetic field that operates the damping force variable means in the damping force control means. converted into a generated signal. Note that the strength of this magnetic field generation signal corresponds to the strength of vibration energy.

The damping force variable means is actuated by this magnetic field generation signal to form a magnetic field having a strength corresponding to the strength of the magnetic field generation signal.

By the way, when unsprung vibration occurs in a vehicle, the shock absorber expands and contracts, and as a result of this expansion and contraction, displacement flow of the magnetic fluid occurs in the flow path in which the damping force variable means is provided.

The viscosity of this displacing magnetic fluid changes according to the strength of the magnetic field generated by the damping force variable means, and a damping force corresponding to this viscosity is generated within the shock absorber. becomes. That is, the higher the viscosity, the higher the damping force, and the lower the viscosity, the lower the damping force.

Therefore, the damping force variable means uses the vibration energy of the damping force control means accompanying the unsprung vibration of the vehicle as a driving source, and the damping force increases as the unsprung vibration of the vehicle increases, and the damping force increases as the unsprung vibration of the vehicle decreases. Operates to reduce force.

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

First, the configuration of the embodiment shown in FIGS. 1 and 2 will be described.

Variable damping force shock absorber device A according to an embodiment of the present invention
is provided in the suspension of the vehicle, and includes a shock absorber B and damping force control means C.

First, the structure of the shock absorber B will be explained based on FIG. This shock absorber B includes a cylinder tube 10, a piston 20, a piston rod 30, an outer cylinder 40, and a damping force variable means 60.

The cylinder tube 10 has a double cylindrical shape, consisting of a first tube 10a and a second tube tab, with a communication path 5O formed between them, and has a bottom body 12 at the lower part, and has an upper end opening closed with a guide member 13. , a magnetic fluid F is filled inside.

Further, the first tube LOa has two parts, an upper liquid chamber 14 and a lower liquid chamber 15, by a slidably inserted piston 20.
It is divided into chambers, and a communication hole 16 is opened in the upper part to communicate the upper liquid chamber 14 and the communication path 50.

A cylindrical protrusion 121 is formed in the bottom center of the bottom body 12, and a first variable orifice 122 communicating with the lower liquid chamber 15 is formed in the protrusion 121. A second variable orifice 123 is formed that communicates with the passage 50, and a constant orifice 124 is formed at a location remote from the protrusion 121 of the bottom body 12.

One end of a piston rod 30 is connected to the piston 20, and the piston rod 30 passes through the guide member 13 and projects outside the cylinder tube 10, and its upper end is connected to a vehicle body member (not shown).

The piston 20 also has a through hole 21.22 that communicates the upper liquid chamber 14 and the lower liquid chamber 15, and a through hole 21, 22 that closes the through hole 21 from above and has a minute gap with respect to the through hole 22. The upper plate valve 23 provided and the through hole 22
A damping force generating means 25 is provided, which is comprised of a lower plate valve 24 which is closed from below and is provided with a small gap from the through hole 21 .

The lower outer periphery of the guide member 13 fits into the opening at the upper end of the cylinder tube 10, and the piston rod 30 is slidably guided through the bushing 133 into the central through-hole 131 with a small gap. There is.

The outer cylinder 40 has a cylindrical shape with a bottom, and is connected to the cylinder tube 1.
0 and the guide member 13, and a packing gland 41 is further inserted through the opening at the upper end and the upper end is crimped to accommodate these contents in a liquid-tight manner.

That is, in the space between the outer cylinder 40 and the second tube 10b of the cylinder tube 10, a reservoir chamber 42 filled with a desired amount of magnetic fluid F under the pressure of the enclosed gas is formed.
This reservoir chamber 42 is communicated with the lower liquid chamber 15 via a variable first orifice 122 and a constant orifice 124 of the bottom body 12 of the cylinder tube 10, and is also communicated with the upper liquid chamber 15 via a variable second orifice 123 and a communication passage 50. It communicates with the liquid chamber 14.

45 is a bottom body of the outer cylinder 40, which is provided with a communication space 46 between the bottom body 12 of the cylinder tube 10 and the bottom body 12, as shown in FIG. Corresponding to the shape, a bottomed cylindrical lower protrusion 451 is provided so as to form a communication gap 47 with the protrusion 121 . Further, 48 is a lid body, and an insulator and a mounting ring 481 for attachment to an axle of a vehicle or the like are fixed to this lid body 47.

An air chamber 4 is located between the lid body 48 and the bottom body 45.
9 is formed, and this air chamber 49 is provided with a damping force variable means 60 and a damping force control means C.

As shown in FIG. 2, this damping force variable means 60 is arranged around the outer periphery of the lower convex portion 451 of the bottom body 45, and includes a coiled conducting wire that forms a hollow portion 61 below the lower convex portion 451. This damping force variable means 60 is formed of
By changing the strength of the magnetic field generated in approximately the range H when current flows through this conducting wire, the variable first
The viscosity of the magnetic fluid F flowing through the orifice 122 and the variable second orifice 123 is changed to change the damping force generated at these parts.

That is, when the current flowing through the damping force variable means 60 increases and the magnetic field becomes stronger, the viscosity of the magnetic fluid F increases and the damping force increases, and conversely, the current flowing through the damping force variable means 60 decreases and the magnetic field increases. When the magnetic fluid F becomes weaker, the viscosity of the magnetic fluid F becomes lower and the damping force reaches the initially set magnitude.

The damping force control means C outputs a magnetic field generation signal according to the magnitude of unsprung vibration of the vehicle, and the damping force variable means 60
This damping force control means C is provided in the air chamber 49 below the damping force variable means 60, and the second
As shown in the figure, it is composed of a magnet body 71, a diaphragm 72, a magnet side guide 73, and an outer cylinder side guide 74.

As shown in FIG. 2, the magnet body 71 is elastically supported in the center of a diaphragm 72 fixed to the inner periphery of the outer cylinder 40 so as to be able to move in and out of the hollow part 61 of the damping force variable means 60. Further, a magnet side guide 73 is provided on the lower side of the magnet body to guide the outer cylinder side guide 74 fitted to the inner periphery of the outer cylinder 40 to slide in the vertical direction.

Therefore, this magnet body 71 responds to the vibration of the outer cylinder 40, which is the unsprung member of the vehicle, and relatively vibrates up and down so as to move in and out of the hollow part 61 while being guided by both guides 73 and 74. By going in and out of the section 61, an induced current is generated as a magnetic field generation signal in the damping force variable means 60. The magnitude of the induced current as a magnetic field generation signal is determined by the speed in and out of the magnet body 71 and the magnitude of its amplitude. That is, the stronger and faster the unsprung vibration of the vehicle, the greater the damping force variable means 60. The magnitude of the induced current generated in this case increases.

Note that 75A and 75B in the figure are communication holes that communicate the upper and lower air chambers 49 of the diaphragm 72 and the outer cylinder side guide 74.

Next, the operation of the embodiment will be explained.

■During the extension stroke of shock absorber B When shock absorber B performs the extension stroke, piston 2
0 rises, the liquid pressure in the upper liquid chamber 14 increases and the liquid pressure in the lower liquid chamber 15 decreases, so that the magnetic fluid F in the upper liquid chamber 14 passes through the through hole 22 and is throttled by the lower plate valve 24 while flowing to the lower part. The liquid flows into the liquid chamber 15 and generates a damping force. or,
The liquid flows from the upper liquid chamber 14 through the communication path 50, is constricted by the orifice 123 (generating a damping force), and flows out into the reservoir chamber 42.

In addition, in response to the rise of the piston 20 in this extension stroke, the lower liquid chamber 15 is transferred from the reservoir chamber 42 via the variable first orifice 122 and the constant orifice 124.
A magnetic fluid F is exchanged and flows through these orifices 122 and 124 to compensate for the rod withdrawal from the reservoir chamber 42.
A damping force is generated at .

The damping force (
(mainly generated in the orifice 123) is the damping force variable means 6
0 and the damping force control mechanism C according to the magnitude of the unsprung vibration of the vehicle.

Furthermore, to explain the control operation of the damping force control mechanism C, first, in response to the unsprung vibration of the vehicle, the magnet body 71 elastically supported by the diaphragm 72 moves between both guides 73.
．． 74 to vibrate up and down.

This vertical vibration causes the magnet body 71 to move in and out of the hollow portion 61 of the variable damping force means 60, thereby generating an induced current as a magnetic field generation signal in the variable damping force means 60. The magnitude of this induced current corresponds to the vibration z of the magnet body 71, that is, it corresponds to the unsprung vibration of the vehicle.

In this damping force variable means 60, a magnetic field with a strength corresponding to the magnitude of the induced current is generated, and the first . 2nd variable orifice 122.123
The viscosity of the magnetic fluid F flowing through the communication gap 47 changes, and thereby the magnitude of the generated damping force changes.

Therefore, the larger and faster the unsprung vibration of the vehicle, the larger the induced current generated in the damping force variable means 60 and the stronger the magnetic field, which increases the viscosity of the magnetic fluid F in the range H and increases the damping force. is adjusted to a greater extent, and the smaller and slower the unsprung vibration of the vehicle is, the smaller the induced current generated in the damping force variable means 60 becomes, and the strength of the magnetic field becomes weaker, thereby lowering the viscosity of the magnetic fluid F. The damping force is adjusted to a smaller value and approaches the initial setting value.

■During the compression stroke of the shock absorber C, the lower fluid pressure of the lower fluid chamber 15 increases due to the lowering of the piston 20. This fluid pressure causes the magnetic fluid F to open the upper plate valve 23 of the piston 20 and flow through the through hole 21 to the upper fluid chamber 15. The liquid flows into the liquid chamber 14 while being throttled, producing a damping force.

In addition, in accordance with the downward movement of the piston 20, the lower liquid chamber 1
5 to variable double orifice 122. Via the constant orifices 124, a magnetic fluid F is exchanged into the reservoir chamber 42, producing a damping force in these orifices 122,124.

In this compression stroke, variable clause 1. 2nd orifice 12
The damping force generated in step 2 is adjusted by the damping force variable means 60 and the damping force control means C in accordance with the unsprung vibration of the vehicle, similarly to the above-mentioned extension stroke.

Since the variable damping force shock absorber device A according to the embodiment of the present invention is configured as described above, the following effects can be obtained.

■ The damping force control means C, including the drive source of the damping force variable means 60, are all provided within the shock absorber B and do not require a harness for external connection, so the structure is simple and the harness handling is simple. The effect is that there is no need to worry about connection reliability, and furthermore, the cost can be reduced by not using a harness.

■ Since the damping force generated by the damping force variable means 60 is adjusted by the damping force control means C in accordance with the unsprung vibration of the vehicle, fine and wide damping force control is achieved and handling stability is improved. This effect can be obtained.

(2) Since the damping force variable means 60 uses the vibration energy of the magnet body 71 due to the unsprung vibration of the vehicle as a driving source, it is possible to effectively utilize energy without using electric power from the battery.

Furthermore, since battery power is not required, there is no need to consider battery capacity or alternator power generation capacity, and the amount of vehicle power that is not required by the damping force variable means 60 or the damping force control means C can be used by other vehicles. This has the effect of improving the degree of freedom in design.

■ The damping force variable means 60 is formed of a simple coil-shaped conducting wire, and the damping force control means C is composed of a magnet body 71, a diaphragm 72, and both guides 73 and 74, and does not use a controller, switch, or harness. Therefore, an effect can be obtained that it can be manufactured at low cost.

Although the embodiments of the present invention have been described above in detail with reference to the drawings, the specific configuration is not limited to these embodiments, and the present invention may be modified without departing from the gist of the present invention. included.

For example, although the variable damping force shock absorber device of the present invention is used for a shock absorber having a structure in which the outer cylinder side is under the spring, it may also be applied to a shock absorber having a structure in which the piston rod side is under the spring, which is generally called an inverted type. In that case, the damping force variable means is provided on the piston rod side.

Further, in the embodiment, an induced current is generated as a magnetic field generation signal directly from the damping force control means to the damping force variable means, but an induced current is generated in the damping force control means and is transmitted to the damping force variable means. You can do it like this.

In addition, in the embodiment, the damping force of the shock absorber was controlled only by the damping force control means provided inside the shock absorber. The degree of damping force variation (gain) may be supplementarily controlled according to the vehicle running state.

(Effects of the Invention) As explained above, the variable damping force shock absorber device of the present invention provides the following effects.

Since the damping force control means including the drive source is provided inside the shock absorber, there is no need for a harness that connects the external drive source, switch, or controller to the damping force variable means, making it easier to route and connect the harness. There is no need to worry about reliability, the structure is simple, and the cost can be reduced by the cost of the harness.

In addition, since the vibration energy of the damping force control means associated with the unsprung vibration of the vehicle is used as the drive source, there is no need to consider battery capacity or alternator power generation capacity, resulting in an improved degree of design freedom. In addition, the effect of effectively utilizing energy can also be obtained.

Furthermore, the damping force control mechanism changes the damping force in response to the vehicle's unsprung vibrations, allowing fine-grained and wide-ranging control to improve maneuverability and driving stability. You can get the effect that you can.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a variable damping force shock absorber device according to an embodiment of the present invention, and FIG. 2 is a sectional view showing essential parts of the device according to the embodiment of the present invention. A... Variable damping force shock absorber device B... Shock absorber C... Damping force control means F... Magnetic fluid 10... Cylinder tube 20... Piston 30... Piston rod 60...・Damping force variable means

Claims (1)

[Scope of Claims] 1) a shock absorber having a cylinder tube, a piston, a piston rod, and an outer cylinder; a magnetic fluid filled in a liquid chamber of the shock absorber; A damping force variable means is provided in a flow path in which the magnetic fluid displaces and flows, and changes the damping force by changing the viscosity of the magnetic fluid in the flow path using a magnetic field; a damping force control means for inputting a magnetic field generation signal corresponding to the strength of vibration and outputting a magnetic field generation signal to the damping force variable means.