JPH02209644A - Shock absorber - Google Patents

Abstract

PURPOSE:To make the device effectively exhibit vibration isolation effect by providing a balance rod extended from a piston member so as to be slidable on the other blockading wall of the device main body and penetrate it fluid tightly. CONSTITUTION:A working rod 44 is extended from a piston 28 partitioning a cylinder chamber 24 into two fluid chambers 30, 32. On the other side of the piston, a balance rod 50 having same diameter as that of the working rod 44 is extended. A damping force introduced by flow resistance of electroviscous fluid flowing through a communicating passage 40, appears as pressure variation in the fluid chambers 30, 32, and appears as the braking force against movement of the piston 28. Thus, the vibration input between the working rod 44 and the device main body 20 is damped.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a shock absorber for damping vibrations, and in particular, the present invention relates to a shock absorber for damping vibrations, and in particular, it is used in conjunction with a vibration isolating support device for supporting an automobile engine. The present invention relates to a shock absorber suitable for use in preventing rocking.

(Background Art) In automobiles, in order to prevent engine vibrations from being transmitted to the vehicle body and reducing ride comfort, it is common practice to elastically support the engine with a plurality of anti-vibration support devices such as anti-vibration rubber. It is being done.

The more flexible the spring elasticity of the anti-vibration support device is, the more effective the isolation of vibration by the anti-vibration support device is. It is desirable to do so. However, if the spring elasticity of the anti-vibration support device is made more flexible, the engine will be more likely to shake, and the engine will not be able to shake excessively when starting suddenly, braking, turning sharply, or when driving on rough roads. It shakes, resulting in poor handling stability and ride comfort.

Therefore, in automobiles, especially front-wheel drive cars that tend to have the above-mentioned tendency, in order to suppress the excessive shaking of the engine during sudden starts, sudden braking, etc., an anti-vibration support device is installed to support the engine. It is often practiced to provide a shock absorber.

By the way, as a shock absorber for suppressing the vibration of an automobile engine, the damping force characteristics can be selected from a relatively wide range, so it is possible to obtain the damping force by utilizing the flow resistance when the liquid passes through the orifice. A liquid type is generally used. However, in such conventional liquid shock absorbers, when changing the damping force characteristics, it is necessary to provide a complicated movable mechanism to change the shape of the orifice, which makes the configuration significantly complicated. Therefore, in reality, shock absorbers for suppressing automobile engine vibrations have damping force characteristics set to a constant value.

However, when such a shock absorber having constant damping force characteristics is adopted as a shock absorber for suppressing vibration of an automobile engine, the following problems occur.

In other words, in order to effectively suppress excessive shaking of the engine during sudden starts, sudden braking, sudden turns, or when shaking occurs when driving on rough roads, setting the damping force characteristics of the shock absorber to a large value will cause the engine to As a result of being supported robustly by the shock absorber, the engine support remains rigid even during idling and steady driving, where flexible engine support is required, and the vibration isolating effect of the anti-vibration support device is improved. This results in problems such as deterioration of ride comfort during idling and steady running.On the other hand, it is possible to flexibly support the engine during idling and steady running, and to maintain the vibration isolation effect of the anti-vibration support device. If the damping force characteristics of the shock absorber are set to a small value in order to achieve good performance, it will not be possible to effectively suppress engine vibration, and running stability and ride comfort will deteriorate during sudden starts, sudden braking, etc. There are problems like this.

(Problem to be solved) Against this background, the present invention was made with the direct purpose of obtaining a suitable shock absorber for use in suppressing the vibration of an automobile engine, and the present invention has been made to solve the problem. The problem to be solved is to realize, with a relatively simple configuration, a shock absorber having a function of allowing the damping force characteristics to be set to a large value while also suppressing the damping force characteristics to a small value as necessary.

(Solution Means) In order to solve this problem, the present invention includes (a) a device main body having a structure in which openings at both ends of a cylindrical body are fluid-tightly closed by closing walls; (c) an inner cylindrical body disposed at a predetermined distance from the cylindrical body within the apparatus main body and partitioning a space within the apparatus main body into an inner cylinder chamber and an outer annular space; a piston member that is slidably fitted to the inner surface of the cylindrical body and partitions the cylinder chamber into two fluid chambers; and (d) two fluid chambers partitioned by the piston member using the annular space. (e) an electrorheological fluid filled in the communication path and the two fluid chambers; and (f) one of the closing walls of the device main body is slidable. and (g) a working rod extending from the piston member in a fluid-tight manner and extending through the piston member in a slidable and fluid-tight manner through the other of the closing walls of the device body. (h) a balance rod having the same cross-sectional area as the working rod;
and at least one set of electrodes for applying a voltage to the electrorheological fluid located in the communication path, the buffer device being arranged to face each other with at least a part of the communication path in between. was constructed.

Note that an electrorheological fluid is a fluid whose viscosity changes in appearance or substantially due to the presence of an external electric field, and generally has the property that the viscosity increases as the external electric field increases. ing.

(Function) The shock absorbing device according to the present invention is used so that vibrations to be damped are input between the device body and the working rod. When vibration is input between the device body and the working rod,
As a result of the relative movement of the piston member connected to the working rod with respect to the device body, the electrorheological fluid flows from one fluid chamber of the cylinder chamber to the other fluid chamber through the communication path, and the electrorheological fluid flows through the communication path. Due to the flow resistance of the electrorheological fluid at this time, a pressure change occurs in each fluid chamber of the cylinder chamber in a direction that restricts the movement of the piston member. Then, the pressure change acts on the piston member as a damping force and further as a braking force, suppressing the relative movement between the working rod and the device body, and damping the vibration input between the device body and the working rod. I am forced to do it.

Here, if a voltage is applied between the electrodes that are disposed to face each other across the communication path, the viscosity of the electrorheological fluid located between the electrodes will substantially increase, and as a result, the electric current flowing through the communication path will increase. The flow resistance of the viscous fluid increases, and the damping force acting on the piston member due to the flow resistance increases, as well as the braking force that suppresses relative movement between the working rod and the main body of the device. - Conversely, if the voltage applied between the electrodes is removed or the applied voltage is reduced, the viscosity of the electrorheological fluid located between the electrodes will substantially decrease, and therefore the flow resistance will decrease. As a result, the damping force that acts on the piston member and furthermore the braking force that suppresses relative movement between the working rod and the main body of the device also decreases.

Therefore, if the shock absorber according to the present invention is adopted as a shock absorber for suppressing vibration of an automobile engine, the engine It becomes possible to appropriately control the support state of the vehicle according to the driving state of the vehicle.

In other words, when a sudden start, sudden braking, sudden turn, or when shaking occurs when driving on a rough road, by applying a voltage between the electrodes of the shock absorber, the damping force characteristic is set to a large value to maintain the engine support state. This makes it possible to effectively suppress excessive vibration of the engine, and during idling or steady running, the voltage applied between the electrodes of the shock absorber is released or applied. By reducing the voltage, the damping force characteristics can be reduced (suppressed), the engine support state can be made flexible, and the vibration isolating effect of the vibration isolating support device can be effectively exhibited.

Note that the balance rod, which extends from the piston member to the opposite side of the working rod, serves to keep constant the amount of change in volume of the two fluid chambers partitioned by the piston member.

(Example) In order to make the present invention more concrete, an example will be described based on the drawings in the case where the present invention is applied to a shock absorber for suppressing vibration of an automobile engine. This will be explained in detail.

First, FIG. 1 shows an example of a shock absorber according to the present invention. Here, 10 is a thick-walled cylindrical metal cylinder as a cylindrical body, and each end thereof has a structure that fluid-tightly closes the opening of the cylindrical body 10.
Metal closure member 1 as a closure wall exhibiting a thick disk shape
2.14 is installed. A cup-shaped metal bracket 18 is provided on the outer surface of one of the closing members 14 at the opening edge.
Attachment bolts 16 are erected at 8 to form a main body 20 of the device.

Inside the cylindrical body 10 of the device main body 20, a thin cylindrical inner cylindrical body 22 made of metal is provided as an inner cylindrical body.
0 and a predetermined distance, for example, about 2InI11, and are arranged concentrically with respect to the cylindrical body 10 of the device main body 20.
The inner cylindrical body 22 partitions the inner space into an inner cylinder chamber 24 and an outer cylindrical space 26 . An insulating piston 28 made of a predetermined resin material is slidably fitted onto the inner peripheral surface of the inner cylindrical body 22, and the cylinder chamber 24 is partitioned into two fluid chambers 30 and 32. Note that an annular seal 3 is provided on the outer peripheral surface of the piston 28 to increase fluid tightness between the fluid chambers 30 and 32.
3 are arranged.

On the other hand, the inner cylindrical body 22 into which the piston 28 is fitted
As shown in FIG. 2, an insulating strip 34 of a constant width made of a resin material such as nylon, acrylic, Teflon (trade name) or a rubber material is spirally arranged at an equal pitch on the outer peripheral surface of the The inner circle is wrapped around the inner circle as shown in Figure 1.

A cylindrical space 26 between the cylindrical body 22 and the cylindrical body 10 of the device main body 20 is helically partitioned by the band-like body 34. A spiral space within the cylindrical space 26 partitioned by the strip 34 is communicated with the fluid chamber 30.32 through through holes 36.38 formed at both ends of the inner cylindrical body 22. A spiral communication path 40 having a constant cross-sectional area is formed, and the communication path 40 and the fluid chambers 30, 32 are each filled with a predetermined electrorheological fluid.

Note that this electrorheological fluid is, for example, kerosene.

It is obtained by dispersing ultrafine powder such as silica gel or cellulose in a solvent such as silicone oil, and its viscosity changes depending on the presence of an external electric field (generally, the viscosity increases as the external electric field increases). ).

Furthermore, as shown in detail in FIG. 2, the band-shaped body 34 is partially accommodated and positioned in a spiral groove 42 formed on the outer peripheral surface of the inner cylindrical body 22. It is also possible to position and fix the strip 34 by simply gluing it to the outer peripheral surface of the inner cylindrical body 22, or to attach the strip 34 to the inner cylindrical body 22 by injection molding, vulcanization molding, etc.
4 may be integrally formed and positioned and fixed.

Here, the cylinder chamber 24 is divided into two fluid chambers 30 and 32.
The piston 28 that separates the cup-shaped bracket 18 from the piston 28 slideably and fluid-tightly penetrates the closing member 12 on the non-disposed side of the cup-shaped bracket 18, and the tip protrudes to the outside of the device main body 20. The working rod 44, which is provided with a threaded part 46 for attachment, is extended and slidably and fluid-tightly penetrates the closing member 14 on the disposed side of the cup-shaped bracket 18, so that the distal end of the working rod 44 is extended. The working rod 44 is inserted into the inner space 48 of the cup-shaped bracket.
A balance rod 50 having the same diameter is extended. As a result, as will be described later, when a vibration load is input between the action rod 44 and the device main body 20 and the piston 28 is moved within the cylinder chamber 24,
Said two fluid chambers 30, 32 separated by a piston 28
The amount of change in volume is always the same.

Note that the action rod 44 and the balance rod 50 can be configured as separate members, but here,
These are constructed as an integral member, and the piston 28 is integrally fixed and molded to this member.

Further, the inner space 48 of the bracket 18 can be kept in a sealed state, but here, it is opened to the atmosphere through a through hole (not shown).

By the way, the portion of the closing member 12.14 that comes into contact with the end surface of the inner cylindrical body 22 is as shown in FIG.
An annular insulating ring 5 made of a predetermined insulating material such as resin
2.54, whereby the strip 3
4 and the piston 28 are made of an insulating material, and the inner cylindrical body 22 and the cylindrical body 10 of the device main body 20, which face each other with the communication path 40 in between, are electrically separated from each other. Here, a power source (not shown) is connected to the electrically separated inner cylindrical body 22 and the cylindrical body 10 of the device main body 20, and between these cylindrical bodies 22.10, and furthermore, between these cylindrical bodies 22.10. A predetermined voltage can be applied to the electrorheological fluid within the communication path 40 sandwiched therebetween.

That is, the cylindrical body 10 of the device main body 20 is
The inner cylindrical body 22 is arranged to fluid-tightly penetrate the closing member 12 on the working rod 44 side. It is connected to a power source via an energized cable 56 provided therein. As is clear from this, here, the device main body 2
The cylindrical body 10 and the inner cylindrical body 22 constitute electrodes that face each other with the communication path 40 in between.

In addition, in FIG. 1, 5th is a cable seal for preventing leakage of electrorheological fluid from the penetration part of the energizing cable 56.

Such a shock absorber is normally attached to the vehicle body side with a mounting bolt 16 of the device body 20, while an operating rod 44
It is attached to the engine side with a mounting screw portion 46, and is used so that vibrations to be damped are input between the device body 20 and the working rod 44. When no vibration load is input, the piston 2 is normally positioned in the middle of the cylinder chamber 24, that is, the piston 2
8 is set so that it can move in either direction toward the working rod 44 or toward the balance rod 50.

When a vibration load is input between the device main body 20 and the working rod 44 in this installed state, the piston 28 is moved within the cylinder chamber 24, and a communication path is created from one side of the fluid chamber 30, 32 to the other. An electrorheological fluid is flowed through 40. As a result, the piston 2
The pressure change in the direction that restricts the movement of the fluid chamber 30.32
The movement of the piston 28 and thus the working rod 4 due to the pressure change caused in its fluid chamber 30.32
4 and the device main body 20 as well as displacement of the engine relative to the vehicle body.

In other words, the damping force caused by the flow resistance of the electrorheological fluid flowing through the communication path 40 is expressed as a pressure change in the fluid chambers 30 and 32, and is expressed as a braking force against the movement of the piston 28. Vibration input between the operating rod 44 and the device main body 20 is attenuated, and displacement of the engine relative to the vehicle body is suppressed.

Here, while no voltage is applied between the cylindrical body 10 serving as an electrode and the inner cylindrical body 22 provided with the communication path 40 in between, or while the applied voltage is low, the electricity located in the communication path 40 is The viscosity of the viscous fluid remains substantially low (apparently high) and thus resists the damping forces induced due to the flow resistance of the electrorheological fluid as well as the relative movement of the working rod 44 and the device body 20. The braking force is also suppressed to a small level, but when a voltage of a certain magnitude is applied between the cylindrical body 10 and the inner cylindrical body 22, the viscosity of the electrorheological fluid located in the communication passage 40 substantially decreases. As a result, the flow resistance of the electrorheological fluid flowing through the communication path 40 increases significantly, and as a result, the damping force due to the flow resistance of the electrorheological fluid, as well as the working rod 44 and the device body 20 The braking force for relative movement with the vehicle will also increase significantly.

Therefore, when a sudden start, sudden braking, sudden turn, or shaking occurs when driving on a rough road, the cylindrical body 10 and the inner cylindrical body 2
While applying a certain amount of voltage between
If the voltage applied to the cylindrical body 10 and the inner cylindrical body 22 is removed from being applied to the cylindrical body 10 and the inner cylindrical body 22 during idling or steady running, or if the applied voltage is set to a low value, it will be possible to prevent the application of voltage during sudden starts, sudden braking, sudden turns, or rough roads. This makes it possible to effectively suppress excessive vibrations of the engine when shaking occurs while driving, and also prevents vibrations transmitted from the engine to the vehicle body during idling or steady driving using anti-vibration rubber. The vibration support device makes it possible to effectively insulate the vehicle, thereby maintaining good ride comfort during idling and steady driving.
This makes it possible to satisfactorily avoid a decrease in running stability and ride comfort of the vehicle during sudden starts, sudden braking, sudden turns, or when shaking occurs when driving on rough roads.

In this way, according to the device of this embodiment, there is no need to employ a complicated movable mechanism that changes the shape of the communication path 40.
By simply controlling the voltage applied between the cylindrical body 10 and the inner cylindrical body 22, which are provided to face each other across the communication path 40,
The support state of the engine can always be appropriately controlled according to the driving state of the automobile, and therefore, such a control function for the engine support state can be realized with a simpler structure than before.

Incidentally, in FIG. 3, the voltage applied between the cylindrical body 10 and the inner cylindrical body 12 is O(V), 6 (kV) in a shock absorber having a structure similar to that of the apparatus of this embodiment.

The measurement results of the damping force characteristics measured by changing the voltage to 10 (kV) are shown. From this figure, it can be seen that in the device of this embodiment, the support state of the engine is always adjusted appropriately depending on the running state by controlling the voltage applied between the cylindrical body 10 and the inner cylindrical body 22 according to the running state. It is recognized that it can be controlled.

Although one embodiment of the present invention has been described in detail above, this is a literal illustration, and the present invention is not limited to such a specific example, and within the scope of the spirit thereof,
It goes without saying that the present invention can be implemented with various changes, modifications, improvements, etc.

For example, in the embodiment described above, the band member 34 is spirally wound around the outer peripheral surface of the inner cylindrical body 22, and the communication passage 40 that communicates the fluid chambers 30, 32 is formed in a spiral shape. The passage 40 can have a shape other than a spiral, and depending on the required characteristics, the cylindrical space 26 can be used as it is as a communication passage.

Further, in the above embodiment, the cylindrical body 1O and the inner cylindrical body 22 of the device main body 20, which face each other with the communication passage 40 in between, are both entirely made of metal material, and the inner and outer walls face each other with the communication passage 40 in between. were all considered to be electrodes, but the communication path 40
It is not necessarily necessary that all of the inner and outer wall surfaces facing each other with the communication path 40 in between are made of an electrode material. As long as it is an electrode, the effects of the present invention can be enjoyed regardless of the shape or arrangement of the electrode.

Further, in the above embodiment, an example was described in which the present invention was applied to a shock absorber used to suppress vibration of an automobile engine, but the present invention may also be applied to a shock absorber used for other purposes. Of course, it is also possible.

(Effects of the Invention) As is clear from the above description, according to the present invention, a shock absorber having a function of setting a large damping force characteristic and suppressing the damping force characteristic to a small value as necessary is provided. This can be achieved with a simple configuration that simply controls the state of voltage applied to electrodes placed opposite each other across a communication path, and the damping force characteristics can be adjusted depending on the situation, such as for the purpose of suppressing vibrations in an automobile engine. Used when it is necessary to control increase or decrease,
It is possible to achieve excellent effects.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing an example of a shock absorbing device according to the present invention, and FIG. 2 is an explanatory diagram for explaining the arrangement of the band-shaped body with respect to the inner cylindrical body of the device shown in FIG. FIG. 3 is a graph showing an example of measurement results of damping force characteristics measured for a shock absorber having a configuration similar to that of the device shown in FIG. 10: Cylindrical body (cylindrical body) 12.14: Closing member (blocking wall) 20: Device main body 22: Inner cylindrical body (inner cylindrical member) 24 Niji cylinder chamber 26: Cylindrical space 28: Piston 30.32 = Fluid chamber 34: Band-shaped body 40:
Communication path 44: Working rod 50: Balance rod 52.54
= insulation ring

Claims (1)

[Scope of Claims] A device main body having a structure in which openings at both ends of a cylindrical body are fluid-tightly closed by closing walls, and a device body disposed within the device main body at a predetermined distance from the cylindrical body, an inner cylindrical body that partitions the space within the device body into an inner cylinder chamber and an outer annular space; and an inner cylindrical body that is slidably fitted on the inner surface of the inner cylindrical body to partition the cylinder chamber into two fluid chambers. a piston member; a communication path formed to communicate two fluid chambers partitioned by the piston member using the annular space; and electricity filled in the communication path and the two fluid chambers. a viscous fluid; an operating rod extending from the piston member to slidably and fluid-tightly penetrate one of the closing walls of the device body; and a working rod slidably extending through the other of the closing walls of the device body. a balance rod extending from the piston member in a fluid-tight manner and having the same cross-sectional area as the working rod; and at least a portion of each of the cylindrical body of the device main body and the inner cylindrical body. and at least one set of electrodes for applying a voltage to the electrorheological fluid located in the communication path, which are provided to face each other with at least a part of the communication path in between, A buffer device comprising: