JP2002195339A - Shock absorber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shock absorber capable of simultaneously utilizing magnetic fluid and specified working fluid. SOLUTION: This shock absorber comprises a housing having an internal space for storing the working fluid therein, a cylinder having an upper operating chamber filled with MR fluid and a lower operating chamber filled with the working fluid, a piston rod slidably inserted into the upper operating chamber of the cylinder, a piston slidably inserted into the lower operating chamber of the cylinder, fixed to the piston rod, and formed so as to form a magnetic field generating device, and a chamber fixed to the piston rod. The piston rod comprises at least one or more first openings serving as the flowing route of the MR fluid, and the piston comprises at least one or more openings serving as the flowing route of the working fluid.

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 automobiles, and more particularly, to a shock absorber that simultaneously uses an MR fluid and a predetermined working fluid.

[0002]

2. Description of the Related Art Generally, an automobile is provided with a suspension device for improving the contact with a road surface and improving the riding 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.

A shock absorber is a working fluid having a constant viscosity or, for example, an MR fluid (magnetorheological (M
R) Use a fluid flow system that includes a fluid of varying viscosity, such as fluid). The use of the MR fluid has the advantage that the viscosity can be adjusted by applying a magnetic field in order to adjust the damping force applied to the spring according to the operating condition.

[0004] In particular, MR fluids have a constant viscosity and are free-flowing. When exposed to a magnetic field, the liquid instantaneously changes from a liquid to a solid state, and when the magnetic field is removed, the fluid quickly returns to a liquid state. The change in viscosity of the MR fluid is proportional to the magnitude of the generated magnetic field.

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

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

Generally, the housing 20 has a first closed end 2
2 is a cylindrical tube. The cylindrical sleeve 25 can be secured to the inner cylinder by any conventional means of press bonding, welding, gluing, etc., to increase the cross-sectional area of the housing 20. The cylinder is closed at a second end by an end member 26. First
The airtight means 27 is provided on the outer peripheral portion of the end member 26 in order to prevent the fluid from leaking between the housing 20 and the end member 26. The second annular airtight means 28 is housed in a groove formed on the inner peripheral portion of the end member 26, and keeps airtight with the piston rod 32. The scraper 29 can be used to wipe the MR fluid on the surface of the piston rod 32 to minimize the outflow of the MR fluid through the second hermetic member 28.

The housing 20 has a floating piston for separating the accumulator 23 under pressure from the MR fluid.
21 are provided. The accumulator 23 is necessary to receive the fluid moving by the piston rod 32 and allow the fluid to expand by heat.

The piston assembly 30 is shown in more detail in FIG. The piston head 34 is a spool type having an outwardly extending upper flange 36 and an outwardly extending lower flange 38. A coil 40 is wound around a spool-type piston head 34 between the upper flange 36 and the lower flange 38. The piston head 34 is made of a magnetically permeable material such as low carbon steel. Each guide rail 42 is 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 arranged at regular intervals on the outer peripheral portion of the piston head 34.

[0010] The coil 40 is electrically connected by leads 45 and 47 passing through the interior of the piston rod 32.
The first lead wire 45 extends through the piston rod 32 to a phono jack connector 46, where
Connected to one end. The central connector of the phono jack 46 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 connector outside the phono jack 46. Accordingly, the electrical return path includes the piston rod 32 and the ground lead 47.

However, such shock absorbers have inherent disadvantages. First, the MR fluid contained in the shock absorber has a higher viscosity than a conventional working fluid even in the state where no magnetic field is applied. It tends to give more power and consequently worsens the ride under certain environmental conditions. In addition, MR fluids are expensive, which increases the cost of manufacturing shock absorbers.

[0012]

SUMMARY OF THE INVENTION The present invention has been made in view of such problems, and an object of the present invention is to provide a shock absorber capable of simultaneously using an MR fluid and a normal working fluid. It is in.

[0013]

According to the present invention, there is provided, in accordance with the present invention, a housing having an interior space for containing a fluid, an upper working chamber filled with an MR fluid,
A cylinder having a lower working chamber containing a working fluid; a piston rod slidably inserted into an upper working chamber of the cylinder; and a piston slidably inserted into a lower working chamber of the cylinder. Fixed to the rod,
A piston configured to form a magnetic field generator, and a chamber attached to a piston rod, wherein the piston rod further includes at least one or more first openings serving as a passage through which the MR fluid flows. , The piston further comprises at least one passage through which the fluid flows.
Provided is a shock absorber including one or more second openings.

[0014]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

As shown in FIG. 3, a shock absorber 100 of the present invention used for a vehicle such as an automobile has a housing 110, a cylinder 120, a piston rod 130, a piston 1
40, and a chamber 150.

The housing 110 is provided with a working fluid 1 having a constant viscosity.
Includes an interior space 112 that houses 60.

A cylinder 120 having a first end member 121 and an opposite second end member 122 has an upper working chamber 123 and a lower working chamber 124, and the volume of the upper working chamber 123 is lower working chamber 124. The upper working chamber 123 is filled with an MR fluid 165 whose viscosity can be changed, and the lower working chamber 124 is filled with a working fluid 160. A first end member 121 of the cylinder 120 is fixed to the housing 110 and has an opening 125 shared by each other, and a second end member 122 of the cylinder 120.
Is separated from the housing 110 and the housing 110
Has one or more valves 129, whereby the inner space 112 of the housing 110 and the lower working chamber 1 of the cylinder 120
The working fluid 160 between them can flow.

Further, the cylinder 120 includes a first hermetic member 126, a second hermetic member 127, and a third hermetic member 128 made of a material such as Teflon (registered trademark). The second fluid-tight member 127 prevents the MR fluid 165 and the working fluid 160 from mixing with each other, and the third gas-tight member 128 prevents the MR fluid 165 in the upper working chamber 123 from flowing out. The working fluid 160 in 124 is prevented from flowing along the cylinder 120.

The piston rod 130 has a first portion 131, a second
A first portion 131 is adjacent to the opening 125 of the cylinder 120, and a second portion 132 is adjacent to the upper working chamber 123 of the cylinder 120. A piston rod 130 is slidably inserted into the cylinder 120. The size of the first portion 131 is formed smaller than the size of the second portion 132. Due to the diameter difference between the two parts, a disk-shaped vertical plane 134 is formed between the first part 131 and the second part 132, and the upper operation of the cylinder 120 when the piston rod 130 reciprocates. A change in the MR fluid 165 occurs in the chamber 123. Third portion 133 includes a securing member 136, such as a screw, rivet, connection, etc., that mechanically couples piston rod 130 to chamber 150.

As shown in FIGS. 3 and 4, the piston rod 130 further includes an internal opening 136 and one or more
Includes one opening 135. The internal opening 136 is used to provide an electrical connection (not shown) for applying a current to the piston 140.
It extends from one part 131 to a third part 133. The first opening 135 is provided for the MR fluid 165 in the upper working chamber 123 of the cylinder 120.
It extends from the vertical plane 134 through the piston 140 to the chamber 150 so as to provide a flow path.

The piston 140 has an outer peripheral portion 141 and an inner peripheral portion 142.
The outer peripheral portion 141 is slidably inserted into the lower working chamber 124 of the cylinder 120, and the inner peripheral portion 142 is fixed to the third portion 133 of the piston rod 130. The piston 140 has a coil 143
And one or more second openings 144,
3 is electrically connected to an electrical connection in an internal opening 136 of the piston rod 130, and the second opening 144 provides a flow path for a working fluid 160 in a lower working chamber 124 of the cylinder 120. In addition, the piston 140 extends from the upper portion to the lower portion.

The piston 140 is made of a magnetically permeable material such as ferrite or low carbon steel, and has a structure in which a coil 143 is wound to form a magnetic field generator such as a solenoid. Therefore, through the electrical connection,
When a current is applied to the coil 143, a magnetic field is formed around the piston 140 and the MR fluid 165 passes through the first opening 135.
Is adjusted.

Although a detailed description of the electrical connection is omitted in the present invention, it will be apparent to those skilled in the art that the electrical connection can be formed by various devices and methods in the present invention.

Referring to FIG. 3, the chamber 150 is secured to the third portion 133 of the piston rod 130 by using a fixing means 136.
Mechanically fixed to the Chamber 150 includes a slidably inserted floating piston 152 and an accumulator 154 filled with a gas such as nitrogen, wherein the accumulator 154 includes an MR fluid 165 by a piston rod 130.
Is necessary to allow the MR fluid 165 to expand due to heat.

The operation of the shock absorber 100 will be described below with reference to FIGS.

As shown in FIG. 5, when the housing 110 and the cylinder 120 momentarily move upward due to the applied impact, the piston rod 130 and the piston 140 maintain the original position. The volume of the chamber 123 will increase, and conversely, the lower working chamber 12
The volume of 4 decreases. At the same time, a spring (not shown) provided in parallel with the shock absorber 100 is compressed. Therefore, in order to eliminate the pressure difference, M
The R fluid 165 pulls the floating piston 152 upward,
As a result, the working fluid 160 in the lower working chamber 124 moves upward through the second opening, and at the same time, flows into the housing 110 through the valve 129. It will flow into the space 112.

Thereafter, as shown in FIG. 6, the piston rod 130 and the piston 140 are moved upward by the restoring force of a compressed spring (not shown) provided in parallel with the shock absorber 100. Upper working chamber 123
Is reduced, and conversely, the volume of the lower working chamber 124 of the cylinder 120 is increased. Therefore, in order to eliminate the pressure difference, the MR fluid 165 in the upper working chamber 123 is
In order to flow into the chamber 150 through the opening 135, the floating piston 152 is pushed downward, and the working fluid 160 in the lower working chamber 124 flows downward through the second opening 144, as well as the housing. The working fluid 160 in the internal space 112 of the 110 also flows into the lower working chamber 124 via the valve 129. During this operation, the shock absorber 100 operates as a shock absorber to reduce the vibration of a spring (not shown).

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.

[0029]

Thus, according to the present invention, shock absorber 100 utilizes working fluid 160 and MR fluid 165 simultaneously. Therefore, the shock absorber 100 can respond sensitively to an external impact by using the working fluid 160 having a relatively low viscosity, and at the same time, consider various factors such as a driving state and a driver's operation. Thus, the damping force can be adjusted using the MR fluid 165 having an adjustable viscosity. Furthermore, by using the expensive MR fluid 165 only in the upper working chamber 123 and the chamber 150 of the cylinder 120, the amount of the MR fluid 165 used in the shock absorber 100 can be reduced, and the manufacturing cost can be reduced. .

[Brief description of the drawings]

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

FIG. 2 is an enlarged sectional view illustrating the piston assembly shown in FIG. 1;

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

FIG. 4 is a sectional view taken along line AA of FIG. 3;

5 is a cross-sectional view illustrating a continuous operation of the shock absorber shown in FIG. 3 together with FIG. 6;

6 is a cross-sectional view illustrating a continuous operation of the shock absorber shown in FIG. 3 together with FIG. 5;

[Explanation of symbols]

 100 Shock absorber 110 Housing 120 Cylinder 123 Upper working chamber 124 Lower working chamber 130 Piston rod 135 First opening 140 Piston 143 Coil 144 Second opening 150 Chamber 152 Floating piston 160 Working fluid 165 MR fluid

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) F16F 9/52 F16J 15/16 A F16J 15/16 F16F 9/32 HLNM

Claims (12)

[Claims] A cylinder having an upper working chamber filled with an MR fluid; a lower working chamber filled with a working fluid; and a sliding member in an upper working chamber of the cylinder. A piston rod freely inserted, a piston slidably inserted into a lower working chamber of the cylinder, fixed to the piston rod, and configured to form a magnetic field generator, and fixed to the piston rod. The piston rod further includes at least one or more first openings serving as a flow path for the MR fluid, and the piston further includes at least one or more first paths serving as a flow path for the working fluid. A shock absorber comprising a second opening. 2. The cylinder according to claim 1, wherein said cylinder includes a first end member attached to said housing and an opposite second end member remote from said housing. The shock absorber according to the above. 3. The first end member of the cylinder,
3. The shock absorber according to claim 2, comprising an opening shared with the housing. 4. A second end member of the cylinder,
3. The shock absorber according to claim 2, further comprising at least one valve serving as a flow path of a working fluid between an inner space of the housing and a lower working chamber of a cylinder. 5. The shock absorber according to claim 1, wherein the upper working chamber has a smaller volume than the lower working chamber. 6. The piston rod includes a first portion,
A second portion, and a third portion, wherein the first portion is adjacent to an opening of the cylinder and the second portion is adjacent to the upper working chamber of the cylinder. Item 4. The shock absorber according to item 3. 7. The method according to claim 1, wherein the first opening extends from the upper working chamber to a chamber via a piston, and the second opening extends from an upper part to a lower part of the piston. shock absorber. 8. The shock absorber according to claim 1, wherein the piston is made of a magnetically permeable material, and is wound around a coil to form a solenoid. 9. The chamber includes a floating piston slidably inserted into the chamber, and an accumulator for receiving the MR fluid displaced by the piston rod and allowing thermal expansion of the MR fluid. 2. The shock absorber according to claim 1, wherein 10. The shock absorber according to claim 1, further comprising:
A first hermetic member, a second hermetic member, and a third hermetic member, wherein the first hermetic member prevents the outflow of the MR fluid in the upper working chamber, and the second hermetic member operates with the MR fluid. 2. The shock absorber according to claim 1, wherein mixing of fluids is prevented, and the third airtight member blocks flow of the working fluid along a lower working chamber of the cylinder. An automobile using the shock absorber according to any one of claims 1 to 10. A suspension device using the shock absorber according to any one of claims 1 to 10.