JP2002195340A - Double tube type shock absorber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a double tube type shock absorber capable of simultaneously utilizing MR fluid and specified working fluid. SOLUTION: This double tube type shock absorber comprises an external cylinder having a first operating chamber and an internal cylinder positioned inside the first operating chamber and having a second operating chamber. A first piston and a second piston having a coil are movably inserted into the first and second operating chambers, respectively. The first and second operating chambers are filled with the working fluid and MR fluid, respectively. The first and second pistons comprise at least one or more small openings. The shock absorber further comprises at least one or more first and second piston rods for the reciprocating motion of the first and second pistons. The shock absorber can sensitively respond to an applied impact by using relatively low viscous working fluid, and also a damping force can be adjusted by using the MR fluid with adjustable viscosity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shock absorber for use in a motor vehicle, and more particularly, to an MR (magneto-r).
The present invention relates to a double-tube shock absorber that simultaneously uses a fluid and a predetermined working fluid.

[0002]

2. Description of the Related Art Generally, an automobile is provided with a suspension device for improving adhesion to a road surface and improving ride comfort of a passenger. The suspension includes a spring and a shock absorber. The shock absorber is arranged in parallel with the spring to damp the vibration of the spring.

[0003] Shock absorbers utilize a predetermined working fluid having a constant viscosity, or a fluid flow system that includes a fluid whose viscosity can be adjusted, such as, for example, an MR fluid. The use of the MR fluid has the advantage that the viscosity can be adjusted when a magnetic field is applied to adjust the damping force acting on the spring according to the operation state.

In particular, the MR fluid is a free-flowing liquid having a predetermined viscosity, and can be changed from a liquid to a solid instantaneously when a magnetic field is applied. Quickly returns to liquid state. The degree of the viscosity change of the MR fluid is proportional to the magnitude of the applied magnetic field.

FIGS. 1 and 2 respectively show “MAGNETORHEOLOGI”.
FIG. 5 is a cross-sectional view of a conventional shock absorber using MR fluid and an enlarged cross-sectional view illustrating a piston assembly disclosed in U.S. Pat. No. 5,284,330, entitled "CAL FLUID DEVICE".

[0006] The shock absorber 10 comprises two basic components, a housing 20 and a piston 30. The housing 20 contains a fixed amount of MR fluid. The fluid is composed of carbonyl iron particles suspended in silicone oil.

The housing 20 is a generally closed second housing.
It is a cylindrical tube with one end 22. A cylindrical sleeve tube 25 may be secured to the inner cylinder by any conventional means, such as press-fitting, welding, gluing, to increase the cross-sectional area of the housing 20. The second end of the cylinder is closed by an end member 26.
The first sealing means 27 is provided on the outer peripheral portion of the terminal member 26 in order to prevent fluid from leaking between the housing 20 and the terminal member 26. The second annular sealing means 28 is stored in a groove formed in the inner peripheral portion of the terminal member 26, and is pressed against the piston rod 32 to seal. The scraper 29 is provided to minimize the loss of the MR fluid passing through the second seal member 28.
It can be used to wipe off the MR fluid on the surface of the piston rod 32.

A floating piston is provided in the housing 20 so as to separate the compressed accumulator 23 from the space for the MR fluid.
21 is formed. The accumulator 23 is a piston rod
Needed to balance the movement of the fluid by 32 and to allow thermal expansion of the fluid.

The piston assembly 30 is shown in more detail in FIG. The piston head 34 has a spool shape by including an upper flange 36 and a lower flange 38 projecting outward. A coil 40 is wound around the spool-shaped piston head 34 between the upper flange 36 and the lower flange 38. Piston head 34 is made of a magnetically permeable material such as low carbon steel. Guide rails 42 are mounted on the outer surface of the piston head 34 at regular intervals. As shown in FIGS. 1 and 2, four guide rails 42 are formed uniformly on the outer peripheral portion of the piston head 34.

The coil 40 is electrically connected by wires 45 and 47 passing through the piston rod 32. 1st conductor 45
Is passed through the piston rod 32 and
-jack connector) 46 is connected to a first end of a conductive rod 48 extending to a connection portion. Phono Jack 4
6 is connected to the first end 39 of the coil 40. The second end 41 of the wound coil 40 is connected to a ground connection on the outer surface of the phono jack 46. Therefore, the electrical return passage is made up of the piston rod 32 and the ground conductor.
It will go through 47.

On the other hand, such a shock absorber has a defect. First, the MR fluid contained in the shock absorber has a higher viscosity than conventional working fluids even when no magnetic field is applied, and therefore exhibits a rougher damping force against an applied external impact. This is because they tend to make the ride worse in certain environments.
In addition, MR fluids increase the cost of manufacturing shock absorbers in terms of cost.

[0012]

SUMMARY OF THE INVENTION The present invention has been made in view of such a problem, and an object of the present invention is to provide a double-tube shock absorber capable of simultaneously using an MR fluid and a predetermined working fluid. Is to provide.

[0013]

According to the present invention, there is provided, in accordance with the present invention, a method for filling a first working fluid with a predetermined working fluid.
An outer cylinder having one working chamber, a second working chamber filled with MR fluid, an inner cylinder located in the first working chamber, and at least one slidably inserted in the first working chamber. A first piston having at least one opening;
(2) While slidably inserted into the working chamber, the coil is wound around, a second piston having at least one or more openings, a first piston rod for guiding the first piston to reciprocate, And a second piston rod which guides the two pistons to reciprocate.

[0014]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. As shown in FIG. 3, the double-pipe shock absorber 100 of the present invention used for a vehicle such as an automobile includes a cylinder assembly 110 and a piston assembly 130.

Each of the cylinder assemblies 110 has an outer surface 1
An outer cylinder 112 having an inner surface 21 and an inner surface 122;
123 and an inner cylinder 114 having an inner surface 124. A first working chamber 116 is included in the outer cylinder 112. The internal cylinder 114 includes a second working chamber 118 while being located inside the first working chamber 116. The first working chamber 116 is filled with a predetermined working fluid 126 having a relatively low viscosity, and the second working chamber 118 is filled with the MR fluid 12 having a changeable viscosity.
Filled with eight. In order to prevent the predetermined working fluid 126 and the MR fluid 128 from being mixed with each other, the first working chamber 116 and the second working chamber 118 are separated from each other.

As shown in FIG. 4, the piston assembly 130 includes
First piston 132, second piston 142, three first piston rods 152, second piston rod 154, and rod fixed body 156
Including.

A first piston 132 including an outer peripheral portion 133 and an inner peripheral portion 134 is slidably inserted into the first working chamber 116, and the outer peripheral portion 133 of the first piston 132 is level with the inner surface 122 of the outer cylinder 112. , The inner circumference 134 of the first piston 132 is adjacent to the outer surface 123 of the inner cylinder 114. The first piston 132 is
It includes three first openings 135 for providing a vertical flow path for the working fluid 126 in one working chamber 116. Furthermore, the first
Piston 132 includes first and second seal members 136, 137 made of a material such as Teflon. here,
The working fluid 126 is the outer peripheral portion 133 and the inner peripheral portion 13 of the first piston 132.
In order to prevent the fluid from flowing along 4, the first seal member 13
6 is attached to the outer peripheral portion 133 of the first piston 132, and the second seal member 137 is attached to the inner peripheral portion 134 of the first piston 132.

The second piston 142 having the outer peripheral portion 143 is
The second piston 14 is slidably inserted into the working chamber 118.
The outer periphery 143 of the second is horizontally adjacent to the inner surface 124 of the inner cylinder 114. The second piston 142 is connected to the MR fluid 12 in the second working chamber 118.
Includes three second openings 144 to provide a vertical flow path for 8. MR along the outer peripheral portion 143 of the second piston 142
In order to prevent the fluid 128 from flowing, the second piston 142
Further includes a third seal member 145 made of Teflon or the like and mounted on the outer peripheral portion 143.

Although the number of the first and second openings 135 and 144 is desirably three as described above, the present invention is not limited to this. Depending on the amount of damping force required of the double-tube shock absorber 100, the first and second openings 135 and 144 are respectively
One or more of the first and second pistons 132 and 142 may be formed.

As shown in FIG. 5, the second piston 142 has a spool shape having an upper flange 146 and a lower flange 147, and is made of a magnetically conductive material such as ferrite or low carbon steel. It is formed in a solenoid structure in which a coil 148 is wound around an outer peripheral portion 143 between the solenoid 147 and the 147. Accordingly, when a current is applied to the coil 148, a magnetic field is formed around the second piston 142, so that the viscosity of the MR fluid 128 passing through the second opening 144 can be changed. .

3 and 4, three first piston rods 152 are fixedly attached to the first piston 132 at one end so that the first piston 132 reciprocates. No.
Although it has been described above that the number of one piston rod 152 is desirably three, the present invention is not limited to this. In consideration of various mechanical factors such as balance, tensile force, compression force, and the like added to the first piston rod 152, one or more piston rods 152 are firmly attached to the first piston 132. Can be configured to be mounted.

The second piston rod 154 is connected to the second piston 142
Is firmly attached to the second piston 142 at one end so as to reciprocate. The second piston rod 154 includes an internal space 158 in which an electrical connection (not shown) for applying a current to the coil 148 can be formed.

Since the other ends of the first piston rod 152 and the second piston rod 154 are attached to the rod fitting 156, the first piston rod 152 and the second piston rod 154 can be moved during operation of the double-tube shock absorber 100.
The reciprocating motions of the piston 132 and the second piston 142 are simultaneously performed in an interdependent manner.

The double-tube shock absorber 100 further includes a plurality of first and second sealing means 160, 161, first and second floating pistons 163, 164, and first and second accumulators 165, 1
Including 66. The first sealing means 160 prevents the working fluid 126 from leaking along the first piston rod 152, and the second sealing means 161 prevents the MR fluid 128 from leaking along the second piston rod 154. First
The floating piston 163 and the second floating piston 164 are slidably inserted into the outer cylinder 112 and the inner cylinder 114, respectively. Accumulators for each 16
5, 166 are filled with a gas such as nitrogen, and the first accumulator 165 and the second accumulator 166 measure the movement of the working fluid 126 and the MR fluid 128 by the first piston rod 152 and the second piston rod 154, respectively. Is required to allow thermal expansion of these fluids 126,128.

Although the preferred embodiments of the present invention have been described above, those skilled in the art will be able to make various modifications without departing from the scope of the present invention.

[0026]

Therefore, according to the present invention, the double-tube shock absorber 100 is provided with the working fluid 126 in the first working chamber 116 and the working fluid 126 in the first working chamber 116.
2 The MR fluid 128 in the working chamber 118 is used at the same time. Therefore, the double-tube shock absorber 100 not only obtains a sensitive response by using the working fluid 126 having a relatively low viscosity, but also simultaneously performs various factors such as a driving state, a driver's operation, and the like. Fluid with Adjustable Viscosity in Consideration of Pressure
The damping force can be adjusted using 128. Further, the expensive MR fluid 128 is used only in the second working chamber of the inner cylinder 114, thereby reducing the amount of MR fluid 128 used in the double-tube shock absorber 100 and reducing manufacturing costs. be able to.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a conventional shock absorber using an MR fluid.

FIG. 2 is an enlarged cross-sectional view illustrating the piston assembly shown in FIG.

FIG. 3 is a cross-sectional view illustrating a double-tube shock absorber that simultaneously uses an MR fluid and a predetermined working fluid according to the present invention.

FIG. 4 is a perspective view illustrating a piston assembly of the double-pipe shock absorber shown in FIG. 3;

FIG. 5 is an enlarged sectional view illustrating a portion A in FIG. 3;

[Explanation of symbols]

 10 Shock absorber 20 Housing 21 Floating piston 22 First end 23 Accumulator 25 Sleeve pipe 26 End member 27 Sealing means 28 Annular sealing means 29 Scraper 30 Piston 32 Piston rod 34 Piston head 36 Upper flange 38 Lower flange 39 Coil first end 40 Coil 41 Coil second end 42 Guide rail 45, 47 Conductor 100 Double-tube shock absorber 110 Cylinder assembly 112 External cylinder 114 Internal cylinder 116 First working chamber 118 Second working chamber 126 Working fluid 128 MR fluid 130 Piston assembly 132 First piston 136, 137 Seal member 142 Second piston 152 First piston rod 154 Second piston rod 156 Rod fixed body

Claims (12)

[Claims] An outer cylinder having a first working chamber filled with a predetermined working fluid, an inner cylinder having a second working chamber filled with an MR fluid and located in the first working chamber, A first piston having at least one or more openings slidably inserted into the first working chamber; and at least one coil wound around the coil while being slidably inserted into the second working chamber. A second piston having the opening described above, a first piston rod for guiding the first piston to reciprocate, and a second piston rod for guiding the second piston to reciprocate. Characteristic double-tube shock absorber. 2. The double pipe according to claim 1, wherein the first working chamber and the second working chamber are separated from each other to prevent the working fluid and the MR fluid from being mixed. Type shock absorber. 3. The first piston has an outer peripheral portion and an inner peripheral portion, and further includes a first seal member and a second seal member, wherein the first seal member operates along the outer peripheral portion of the first piston. The second seal member is formed on the inner peripheral portion to prevent the fluid from flowing, and the second seal member is formed on the inner peripheral portion to prevent the working fluid from flowing along the inner peripheral portion of the first piston. 2. The double-pipe shock absorber according to claim 1, wherein the shock absorber is formed as follows. 4. The second piston has an outer periphery, and further includes a third seal member on the outer periphery to prevent the MR fluid from flowing along the outer periphery of the second piston. 2. The double-tube shock absorber according to claim 1, wherein: 5. The double-tube shock according to claim 1, wherein the second piston is made of a magnetically conductive material, and is formed in a solenoid structure by winding the coil around an outer peripheral portion. Absorber. 6. A rod further mounting the first piston rod and the second piston rod at the same time so that the reciprocating movements of the first piston and the second piston are simultaneously performed in an interdependent manner. 2. The double-tube shock absorber according to claim 1, comprising a fixed body. 7. The apparatus according to claim 1, further comprising a plurality of sealing means for preventing the working fluid and the MR fluid from leaking along the first piston rod and the second piston rod, respectively. 2. The double-tube shock absorber according to 1. 8. The double-pipe shock absorber according to claim 1, wherein the second piston rod includes an internal space provided with an electrical connection for applying a current to the coil. 9. The double pipe type as claimed in claim 1, further comprising a first floating piston and a second floating piston slidably inserted into the outer cylinder and the inner cylinder, respectively. shock absorber. 10. The method according to claim 9, further comprising a first accumulator provided in the outer cylinder and filled with gas, and a second accumulator provided in the inner cylinder and filled with gas. The double-tube shock absorber described. 11. An automobile using the double-tube shock absorber according to claim 1. 12. A suspension device using the double-tube shock absorber according to any one of claims 1 to 10.