JP3441211B2 - Variable damping force type shock absorber and magnetic fluid flow control mechanism suitable for it - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable damping force shock absorber, such as a telescopic type or a rotary type, which is used to change the damping force by using a magnetic fluid, and more particularly, to an energizing amount to an electromagnetic coil. A variable damping force shock absorber, such as a telescopic type or a rotary type, that uses a magnetic fluid so that the generated damping force can be adjusted by changing the flow characteristics of the magnetic fluid that passes through the flow path of the magnetic fluid. The present invention also relates to a magnetic fluid flow control mechanism suitable for fluid flow control in the variable damping force shock absorber and other devices.

[0002]

2. Description of the Related Art Expansion and contraction using a magnetic fluid that can adjust the generated damping force by changing the viscosity of the magnetic fluid passing through the flow path of the magnetic fluid by changing the amount of electricity supplied to an electromagnetic coil. A variable damping force type shock absorber is disclosed in, for example, Japanese Utility Model Laid-Open No. 62-151448, and a rotary damping force variable type shock absorber is disclosed in, for example, JP-A-62-251220. However, in the conventional damping force variable type shock absorber described above, the present inventors have already made a more preferable change of the generated damping force even if the amount of electricity to the electromagnetic coil is changed. It was clarified that it is difficult to make adjustments, and a damping force variable type shock absorber using magnetic fluid that can generate a desired magnitude of damping force was newly developed and a patent application (Patent application 5-575 And No.2 specification and drawings) and.

That is, since the increase in the viscosity of the magnetic fluid due to the magnetic field depends on the flow velocity of the fluid, that is, the shear velocity, it is expected that a damping force with a large adjustment width based on the viscosity is generated at a high flow velocity. Difficult things to do,
Moreover, if only the increase in the viscous force due to the magnetic field of the magnetic fluid is
It has been clarified that it is difficult to expect a damping force with a desired adjustment width even when the flow velocity is low.

Therefore, by utilizing the increase in viscosity of the magnetic fluid due to the magnetic field and effectively utilizing the action of the magnetic force of the magnetic field on the magnetic fluid in a plurality of stages, it is possible to achieve a desired flow rate within a wide range. We have developed a variable damping force type shock absorber capable of generating a large amount of damping force.

Further, in the damping force variable type shock absorbers of the retractable type and the rotary type, which have already been applied, there is a problem that the current value flowing to the electromagnetic coil must be a relatively large value. However, the damping force variable type that solves this problem is configured by the structure in which the pole of the core of the electromagnet at the part to which a magnetic field is applied is in contact with the magnetic fluid directly or with almost no gap. A shock absorber and a magnetic fluid flow control mechanism have been newly developed and a patent application has been filed (Japanese Patent Application No. 5-255952 specification and drawings; hereinafter referred to as “application already filed in 1993”).

Further, in the damping force variable type shock absorber of the expansion type, the rotary type, etc., filed in 1993, when a magnetic fluid having a large saturation magnetization is used, the viscosity of the magnetic fluid having a large saturation magnetization is used. Is relatively high, the damping force when no magnetic field is applied, that is, the damping force when the control is not performed, becomes large, and in order to reduce this, the gap in the flow path must be large. However, there was a problem that the current value flowing to the electromagnet coil had to be relatively large, and there was a problem to solve this problem, but the pole part of the core of the electromagnet at the part to which the magnetic field is applied has a magnetic fluid flow. By making it project to the road,
Patent application for an invention that solves this problem (Japanese Patent Application No. 6-123
No. 857 Specification and Drawings; hereinafter “1994 already filed”
And )is doing.

Furthermore, it has been found that power saving can be achieved by providing a magnetic field applying section by a permanent magnet, and a patent application (Japanese Patent Application No. 6-174569 and drawings; "Otsu".)

FIG. 17 and FIG. 18 show a retractable damping force variable type shock absorber in the above-mentioned 1993 application.

In this telescopic damping force variable type shock absorber 1, a piston 4 provided at a lower end of a piston rod 3 which is inserted into a cylinder 2 causes the inside of the cylinder 2 to have a rod side chamber 2a.
And the piston side chamber 2b. The rod-side chamber 2a and the piston-side chamber 2b include a magnetic fluid passage 5 formed outside the cylinder 2, a space 8 formed between the cylinder outer cylinder 6 and the absorber outer cylinder 7, and the cylinder 2
Are communicated with each other via an orifice 11 provided in the bottom lid 9 of the.

The chambers 2a and 2b, the magnetic fluid flow path 5, and a part of the space 8 are filled with the magnetic fluid 10. Further, nitrogen gas is filled in the upper space of the space 8, and the space 8 has a so-called reservoir function.

When extending, the orifice 12 provided in the piston 4 is closed and the bottom lid 9 of the cylinder 2 is closed.
The orifice 11 provided at is opened. Therefore, the magnetic fluid 10 in the rod-side chamber 2a flows downward through the flow path 5, passes through the space 8 and the orifice 11, and then flows into the rod-side chamber 2a.
reflux to b.

When contracting, the orifice 11 provided in the bottom lid 9 of the cylinder 2 is closed, the orifice 12 provided in the piston 4 is opened, and the magnetic fluid 10 in each chamber 2a, 2b in the cylinder 2 is closed. Is pushed out by the volume of the pushed piston rod 3, flows downward through the flow path 5, and flows into the space (reservoir) 8 to be stored.

Therefore, in this case, the flow of the magnetic fluid 10 in the flow path 5 is in the same direction both when it expands and when it contracts. Further, a damping force is generated by the pressure difference generated between the inlet and the outlet of the flow path 5.

Next, in this telescopic damping force variable type shock absorber 1, the magnetic fluid flow control mechanism 1 is provided in the flow path 5 of the magnetic fluid 10.
5, and the structure of the flow path 5 will be described.

The flow path 5 is formed by an annular gap between a cylindrical member 16 provided inside the cylinder outer cylinder 6 and an electromagnet 17 provided outside the cylinder inner cylinder 2. The core 18 of the electromagnet 17 is an annular member having a U-shaped vertical cross section as shown in the drawing, and a large number of cores 18 are arranged outside the cylinder inner cylinder 2. Also, the core 1 of the electromagnet 17
8, an electromagnetic coil 19 is provided. The cylindrical member 16 and the core 18 of the electromagnet 17 are made of a high magnetic permeability material.

FIG. 18 shows an enlarged cross section of this portion.
The pole portions 18a and 18b of the core 18 of the electromagnet 17 are in contact with the magnetic fluid 10 directly or with almost no gap, and as shown in FIG. 18, the core 18, the magnetic fluid 10 in the flow path 5, and the cylinder A magnetic circuit is formed with the member 16.

Therefore, when the electromagnetic coil 19 is energized, a large magnetic field is generated with a small current in the magnetic fluid 10 in the flow path 5.
The magnetic field is applied in the direction orthogonal to the flow direction of the magnetic fluid 10.

The magnitude of the applied magnetic field can be changed by changing the amount of current.

Reference numeral 21 denotes an annular spacer, which is made of a non-magnetic material, and 22 is an annular retainer, which is also made of a non-magnetic material.
Many 7 are arranged outside the cylinder inner cylinder 2 as shown in FIG.

With the structure for applying the magnetic field as described above, the magnetic field can be applied almost perpendicularly to the flow of the magnetic fluid 10 and at many points.

Therefore, by changing the amount of electricity supplied to the electromagnetic coil 19, the viscosity of the magnetic fluid 10 and the magnetic force acting on the magnetic fluid 10 are changed, and the magnetic fluid 10 is changed.
Since the flow can be controlled, the pressure difference generated between the inlet and the outlet of the flow path 5 can be changed, and the damping force can be changed with a relatively small current.

In this case, the spacer 21 and the retainer 22
As the material of the above, a non-magnetic metal such as copper or austenitic stainless steel or a resin such as polytetrafluoroethylene (trade name: Teflon) can be used. Is soft iron, Fe-Si
Any high magnetic permeability material such as alloy, Fe-Al alloy, permalloy, and mumetal can be used. A ferrite core may be used for the core 18, and the use of a high-frequency magnetic material is not limited to these, and the electromagnet 17 having more excellent responsiveness can be obtained.

As a specific dimensional example, the diameter of the piston 4 can be 35 mm and the diameter of the piston rod 3 can be 20 mm. Therefore, the pressure receiving area is 6.48 cm ² when expanding and 3.1 when contracting.
It will be 4 cm ² .

Further, the clearance b of the flow path 5 can be set to b = 1 mm so that the pressure difference when the fluid is not controlled does not become too large even at a piston speed of 0.6 m / sec. 0.6 m /
Even in sec, it is a sufficiently basin.

Further, the cylindrical member 16 may be made of soft iron having a wall thickness of 2 mm, and the annular core 18 is formed as shown in FIG.
, Lc = 6 mm, g = 6 mm, a = 6 mm, h
= 3 mm, the electromagnet 17 can be made of soft iron and has a sufficient magnetic field of 5 kOe.

The annular spacer 21 has a thickness of 2 mm and can be made of polytetrafluoroethylene (trade name: Teflon). As shown in FIG. 17, ten electromagnets 17 may be arranged in the vertical direction. In this case, the magnetic field is applied to a total of 20 points.

Further, the upper space of the space 8 is filled with N ₂ gas at atmospheric pressure, and by having such a structure, the magnetic force is effective as well as the viscous force due to the magnetic field of the magnetic fluid 10. The expansion / contraction damping force variable type shock absorber 1 used for the above (the latter effect is larger) can be used.

FIG. 19, FIG. 20 and FIG. 21 show the rotary damping force variable type shock absorber in the above-mentioned 1993 application.

The rotary damping force variable type shock absorber 31 integrally includes a rotating shaft 32a protruding on one side of the housing 32 and a side plate 32b, and the housing 32 integrally forms with the rotating shaft 32a. Rotate.
A fixed shaft 33 is provided on the side plate 32b side of the other side of the housing 32.
As shown in FIG.
There is c.

On the other hand, the cylindrical body 34 connected to the fixed shaft 33 is provided with a vane 34a, and the housing 32
The space formed by the inner wall 32c in the inside is the vane 3
It is divided into two rooms 35a and 35b by 4a.

Further, inside the cylindrical body 34, there are provided an inner space 41 and an outer space 51 which form two annular shapes. Then, in the respective cylindrical spaces 41 and 51, a magnetic fluid flow control mechanism 45, which will be described in detail below,
55 is provided.

The inner space 41 and the chamber 35a, which form an annular shape, communicate with each other through a flow path 37 (see FIG. 20), and the inner space 41 and the outer space 51 communicate with a flow path 38 (see FIG. 19). The outer space 51 and the room 35b communicate with each other through the flow path 39 (see FIG. 20).

Then, these spaces 41, 51 and room 3
5a, 35b and channels 37, 38, 39 are magnetic fluids 4
It is filled with 0.

Then, when the rotating shaft 32a rotates counterclockwise, as shown in FIG. 20, the magnetic fluid 4 in the chamber 35a is rotated.
0 reaches the inner space 41 through the flow path 37, flows in the inner space 41 through the annular gap 42 from the left to the right in FIG. 19, and then reaches the outer space 51 through the flow path 38.
In the outer space 51, the annular gap 52 flows from the right to the left in FIG. 19, then passes through the flow path 39, and then flows into the room 35b.

When the rotary shaft 32a rotates clockwise, the magnetic fluid 40 flows in the opposite direction to the above.

Next, this rotary damping force variable type shock absorber 31 is used.
Then, since the magnetic fluid flow control mechanisms 45 and 55 are provided in the flow path of the magnetic fluid 40 constituted by the annular gaps 42 and 52, the structure of this flow path will be further described.

The magnetic fluid flow paths are formed by the cylindrical members 46, 5
6 and the electromagnets 47, 57 between the annular gaps 42, 52
Is formed by. Then, the core 4 of the electromagnets 47 and 57
Reference numerals 8 and 58 are annular members having a U-shaped cross section as shown. Electromagnetic coils 49 and 59 are provided on the cores 48 and 58 of the electromagnets 47 and 57, respectively. In this case, the cylindrical members 46 and 56 and the cores 48 and 58 of the electromagnets 47 and 57 are made of a high magnetic permeability material.

FIG. 21 is an enlarged view of this portion. The pole portions 48a, 48 of the cores 48, 58 of the electromagnets 47, 57 are shown.
b, 58a, 58b are in direct contact with the magnetic fluid 40,
As shown in FIG. 21, a magnetic circuit is formed by the cores 48 and 58, the magnetic fluid 40 in the annular gaps (fluid flow paths) 42 and 52, and the cylindrical members 46 and 56.

Therefore, when the electromagnetic coils 49 and 59 are energized, a large magnetic field is generated with a small current by the annular gaps 42 and 5.
2 is applied to the magnetic fluid 40 in
A magnetic field is applied in a direction orthogonal to the direction of zero flow. Also, the magnitude of the applied magnetic field can be changed by changing the amount of current.

Further, 44 and 54 are annular spacers, which are made of a non-magnetic material. In addition, the electromagnet 47,
As shown in FIG. 19, a plurality of 57 are arranged in each of the inner space 41 and the outer space 51.

With the structure for applying the magnetic field as described above, the magnetic field can be applied almost perpendicularly to the flow of the magnetic fluid 40 and at a large number of places (one electromagnet makes two places).

Therefore, the viscosity of the magnetic fluid 40 can be changed by changing the amount of electricity supplied to the electromagnetic coils 49 and 59.
Since the flow of the magnetic fluid 40 can be controlled by changing the magnetic force that acts on the magnetic fluid 40 and the magnetic fluid 40, the pressure difference generated between the inlet and the outlet of the flow path can be changed, and the damping force can be obtained with a relatively small current. Will be able to change.

In this case, the material of the annular spacers 44, 54 is copper, non-magnetic metal such as austenitic stainless steel, polytetrafluoroethylene (trade name: Teflon).
And the like. For the cylindrical members 46 and 56 and the cores 48 and 58 that form the magnetic circuit, soft iron, Fe, etc. can be used.
Any high-permeability material such as --Si alloy, Fe--Al alloy, permalloy, and mumetal can be used. Ferrite cores can be used for the cores 48 and 58, and the electromagnets 47 and 57 having higher responsiveness can be obtained by using not only the ferrite cores but also magnetic materials for high frequencies.

As a specific example of dimensions, the inner diameter of the housing 32 can be 120 mm, the outer diameter of the cylindrical body 34 can be 52 mm, the width of the vanes 34a can be 80 mm, and the flow passages can be formed. Regarding the width b of the annular gaps 42 and 52 shown in FIG. 21, the rotation speed is 100 ° / se
Also in c, b = 1 mm can be set so that the pressure difference when the fluid is not controlled does not become too large, and in this case, it is a sufficiently laminar flow region even at a rotation speed of 100 ° / sec.

Further, the cylindrical members 46 and 56 have a wall thickness of 2 m.
m of soft iron, the annular cores 48, 5
In FIG. 21, 8 is Lc = 6 mm, g = 6 mm, a
= 5 mm and h = 3 mm, the electromagnets 47 and 57 can be made of soft iron and can sufficiently generate a magnetic field of 5 kOe.

Further, the annular spacers 44 and 54 have a thickness of 2 mm and can be made of polytetrafluoroethylene (trade name: Teflon). And electromagnets 47, 5
As shown in FIG. 19, three 7s can be arranged side by side. In this case, the magnetic field is applied to a total of 12 places. , Together with the viscous force due to the magnetic field of the magnetic fluid 40,
It is possible to use the rotary damping force variable shock absorber 31 in which the magnetic force is effectively used (the latter effect is larger).

FIG. 22 shows a separate type magnetic fluid flow control mechanism 75 having a structure separate from the shock absorber main body.

In this separately installed magnetic fluid flow control mechanism 75, inside the housing 85, two annular inner and outer spaces 81 and 91 are provided. The inner space 81 having an annular shape is connected to the channel 71 (7
1a), and the outer space 91 having an annular shape is connected to the flow passage 71.
(71b), the spaces 81 and 91 and the flow path 71 are filled with the magnetic fluid 70.

The magnetic fluid flow path in the magnetic fluid flow control mechanism 75 is formed by annular gaps 82, 92 between the cylindrical members 86, 96 and the electromagnets 87, 97. The cores 88 and 98 of the electromagnets 87 and 97 are annular and have a U-shaped cross section as shown. This electromagnet 87,
The cores 88 and 98 of 97 have electromagnetic coils 89 and 89, respectively.
99 is provided. In this case, the cylindrical members 86, 96
The cores 88 and 98 of the electromagnets 87 and 97 are made of a high magnetic permeability material.

The magnetic fluid 70, for example, enters from the flow path 71a, passes through the inner annular clearance 82, passes through the flow path 84, and then passes through the outer annular clearance 92 and flows into the flow path 71b.

FIG. 23 shows a part of the annular gaps 82 and 92 in an enlarged manner. The pole portions 88a, 88b, 98a and 98b of the cores 88 and 98 of the electromagnets 87 and 97 are directly or almost completely free from the magnetic fluid 70. 23, the cores 88 and 98, the magnetic fluid 70 in the annular gaps (fluid flow paths) 82 and 92, and the cylindrical members 86 and 96 form a magnetic circuit, as shown in FIG. It

Therefore, when the electromagnetic coils 89, 99 are energized, a large magnetic field is generated with a small current by the annular gaps 82, 9.
2 is applied to the magnetic fluid 70 in the
A magnetic field is applied in a direction orthogonal to the direction of zero flow. Also, the magnitude of the applied magnetic field can be changed by changing the amount of current.

Further, 84 and 94 are annular spacers, which are made of a non-magnetic material. In addition, the electromagnet 87,
A plurality of 97 are arranged in the inner space 81 and the outer space 91, respectively, as shown in FIG.

With the structure for applying the magnetic field as described above, the magnetic field can be applied almost perpendicularly to the flow of the magnetic fluid 70 and at a large number of places (one electromagnet makes two places).

Therefore, the viscosity of the magnetic fluid 70 can be changed by changing the amount of electricity supplied to the electromagnetic coils 89 and 99.
Since the flow of the magnetic fluid 70 can be controlled by changing the magnetic force that acts on the magnetic fluid 70 and the magnetic fluid 70, the pressure difference generated between the inlet and the outlet of the flow path can be changed, and the damping force can be obtained with a relatively small current. Will be able to change.

In this case, the material of the annular spacers 84, 94 is copper, a non-magnetic metal such as austenitic stainless steel, polytetrafluoroethylene (trade name: Teflon).
And the like, and the cylindrical members 86 and 96 and the cores 88 and 98 forming the magnetic circuit have high magnetic permeability such as soft iron, Fe-Si alloy, Fe-Al alloy, permalloy, and mumetal. Any material can be used. A ferrite core may be used for the cores 88 and 98, and by using a high frequency magnetic material, the electromagnets 87 and 97 having higher responsiveness can be obtained. In such a magnetic circuit, the cores 88 and 98 are
Since the pole portions 88a, 88b, 98a, 98b of the above are directly in contact with the magnetic fluid 70, it is possible to apply a magnetic field of a certain magnitude or more to the magnetic fluid 70 with a small current.

Further, the cylindrical members 86, 96 and the cores 88, 9
The fact that there is a small gap between the two and 8 is also more convenient. Therefore, a smaller current is sufficient.

In order to prevent rust and insulation, the core 88,
It may be necessary to coat 98, but the thickness of the coating layer at that time is at most 10 μm.
Since it is below the level, there is almost no difference in the current value.

Then, as a concrete example of dimensions, the width b shown in FIG. 23 of the annular gaps 82 and 92 forming the flow path is set to b.
= 1 mm, the cylindrical members 86 and 96 are made of soft iron having a thickness of 2 mm, and the annular cores 88 and 98 are Lc = 6 mm, g = 6 mm, a = 5 mm, h = 3 m in FIG.
It is possible to make the electromagnets 87 and 97 which are made of soft iron and have a sufficient magnetic field of 5 kOe.

The annular spacers 84 and 94 have a thickness of 2
mm and polytetrafluoroethylene (trade name: Teflon)
The electromagnets 87 and 97 may be arranged in three lines as shown in FIG. 22. At this time, the magnetic field is applied to a total of 12 points. By doing so, the magnetic fluid flow control mechanism 75 that effectively utilizes the magnetic force as well as the viscous force due to the magnetic field of the magnetic fluid 70 (the latter effect is greater) can be provided.

FIG. 11 and FIG. 12 show the construction of the essential part of the magnetic fluid flow control mechanism suitable for the telescopic type or rotary type variable damping force type shock absorber in the invention of the above-mentioned application filed in 1994. 20 shows a case where the magnetic fluid flow control mechanisms 45 and 55 provided in the flow path of the magnetic fluid 40 of the rotary damping force variable type shock absorber 31 shown in FIGS. 19 and 20 are improved.

As shown in FIG. 11, the flow path of the magnetic fluid is formed by annular gaps 42 and 52 between the cylindrical members 46 and 56 and the electromagnets 47 and 57. The cores 48 and 58 of the electromagnets 47 and 57 are annular and have a U-shaped cross section as shown. Electromagnetic coils 49 and 59 are provided on the cores 48 and 58 of the electromagnets 47 and 57, respectively. In this case, the cylindrical members 46 and 56 and the cores 48 and 58 of the electromagnets 47 and 57 are made of a high magnetic permeability material.

FIG. 12 is an enlarged view of this portion. The pole portions 48a, 48 of the cores 48, 58 of the electromagnets 47, 57 are shown.
b, 58a, 58b project into the flow path of the magnetic fluid 40 (annular gaps 42, 52), and the pole portions 4 of the cores 48, 58 are provided.
8a, 48b, 58a, and 58b are in sufficient contact with the magnetic fluid 40, and the cores 48 and 58, the magnetic fluid 40 in the annular gaps (fluid flow paths) 42 and 52, and the cylindrical members 46 and 56. A magnetic circuit is formed by.

Therefore, when the electromagnetic coils 49 and 59 are energized, a large magnetic field is generated with a small current by the annular gaps 42 and 5.
2 is applied to the magnetic fluid 40 in
A magnetic field is applied in a direction orthogonal to the direction of zero flow. Also, the magnitude of the applied magnetic field can be changed by changing the amount of current.

In FIGS. 11 and 12, 44, 54
Is an annular spacer made of a non-magnetic material. Further, a plurality of electromagnets 47 and 57 are arranged in the inner space 41 and the outer space 51, respectively, as in the case shown in FIG.

As a structure for applying such a magnetic field, pole portions 48a, 48b, 58a, 5 of the cores 48, 58 are provided.
By making 8b project into the flow path (annular gaps 42, 52) of the magnetic fluid 40, it is possible to apply a sufficient magnetic field almost perpendicularly to the flow of the magnetic fluid 40 and at a number of locations ( Two places with one electromagnet).

Therefore, the flow rate of the magnetic fluid 40 can be controlled by changing the amount of electricity supplied to the electromagnetic coils 49 and 59 by a relatively small current, thereby changing the viscosity of the magnetic fluid 40 and the magnetic force acting on the magnetic fluid 40. Therefore, the pressure difference generated between the inlet and the outlet of the flow path can be changed, and the damping force can be changed with a relatively small current.

In this case, the material of the annular spacers 44, 54 is copper, non-magnetic metal such as austenitic stainless steel, polytetrafluoroethylene (trade name: Teflon).
It is possible to use materials such as
Any non-magnetic material may be used.

Further, the cylindrical member 46 forming the magnetic circuit,
Any material having a high magnetic permeability such as soft iron, Fe-Si alloy, Fe-Al alloy, permalloy, or mumetal can be used for the 56 and the cores 48, 58. Ferrite cores can be used for the cores 48 and 58, and the electromagnets 47 and 57 having higher responsiveness can be obtained by using not only the ferrite cores but also magnetic materials for high frequencies.

In the magnetic circuit in this case, the core 4
Since the pole portions 48a, 48b, 58a, 58b of 8, 58 are directly in contact with the magnetic fluid 40 by projecting into the flow paths (annular gaps 42, 52) of the magnetic fluid 40,
It is possible to apply a magnetic field of a certain magnitude or more to the magnetic fluid 40 with a smaller current.

Further, the cylindrical members 46, 56 and the cores 48, 5
It is also convenient that there is a small gap between the two.

The core 4 is used for rust prevention and insulation.
In some cases, it may be necessary to coat 8,58, but the thickness of the coating layer at that time is at most 10
Since it is about μm or less, there is almost no difference in the current value.

Therefore, in this case, the pole portions 48a, 48b, 58a, 58b of the cores 48, 58 are the magnetic fluid 40.
Since it protrudes into the flow path, it is in direct contact with the magnetic fluid 40, and a magnetic field of a certain magnitude or more can be applied to the magnetic fluid 40 with a small current.

As a specific example of dimensions, the inner diameter of the housing 32 is 140 mm and the outer diameter of the cylindrical body 34 is 72 mm.
mm, and the width of the vane 34a can be 122 mm.

The cylindrical members 46 and 56 have a wall thickness of 2 mm.
It can be made of soft iron. Further, in FIG. 12, the annular cores 48 and 58 have Lc = 8 mm and g = 1.
0mm, a = 5mm, h = 3mm, made of soft iron,
The electromagnets 47 and 57 capable of sufficiently generating a magnetic field of 5 kOe can be used. Also, the pole portions 48a, 48b of the core 48
The projection amount of C ₁ = 1 mm, and the electromagnetic coil 4
9 can be retracted by 1 mm.

The annular spacers 44 and 54 have a thickness of s.
= 8 mm, and the protrusion amount of the pole portions 48a, 48b, 58a, 58b from the annular spacers 44, 54 is C ₂ = 2.
mm, the annular spacers 44, 54 have the pole portions 48a, 4
It can be made of polytetrafluoroethylene (trade name: Teflon) by retracting 2 mm from 8b, 58a, 58b. In addition, the electromagnets 47 and 57 have the same structure as in FIG.
As shown in FIG. 1, three pieces are arranged side by side, and at this time, the magnetic field is applied to a total of 12 places.

The size of the annular gaps 42 and 52 is b =
It can be 1 mm. In this case, the rotation speed is 10
It is a sufficiently laminar flow region even at 0 ° / sec.

With the above configuration, the magnetic fluid 4
The rotary damping force variable shock absorber 31 that effectively utilizes the magnetic force as well as the viscous force due to the magnetic field of 0 (the latter effect is large) can be provided.

FIGS. 3 and 4 show the construction of the essential parts of the magnetic fluid flow control mechanism suitable for the telescopic type or rotary type damping force variable type shock absorber in the invention of the above-mentioned 1994 application. The magnetic fluid flow control mechanism 45, 55 provided in the flow path of the magnetic fluid 40 of the rotary damping force variable type shock absorber 31 shown in FIG. 19 and FIG. The case where the control mechanisms 45 and 55 are further improved is shown.

As shown in FIG. 3, the flow path of the magnetic fluid is between the cylindrical members 46 and 56 and the electromagnets 47 and 57,
And the annular gap 4 between the magnet poles 108 and 118
2, 52. Then, the electromagnets 47, 57
The cores 48 and 58 are of an annular shape having a U-shaped cross section as shown. Cores 48, 58 of the electromagnets 47, 57
Are provided with electromagnetic coils 49 and 59, respectively.

The magnet poles 108 and 118 are annular and have a rectangular cross section as shown. Then, the ring-shaped permanent magnets 109, 1 are brought into contact with the magnet poles 108, 118.
19 are provided, and the annular permanent magnets 109, 1
19 is magnetized in the axial direction.

Further, on the right side of the permanent magnets 109 and 119 in the drawing, magnet poles 110 and 120 which are in contact with the permanent magnets 109 and 119 and have the same shape as the magnet poles 108 and 118 are provided.

The cylindrical members 46 and 56, the electromagnet 47,
The cores 48 and 58 of 57, the magnet poles 108 and 118, and the magnet poles 110 and 120 are made of a high magnetic permeability material.

FIG. 4 is an enlarged view of the magnetic field application portion by the electromagnet and the permanent magnet of FIG.
7 cores 48, 58 pole portions 48a, 48b, 58a, 5
8b projects into the flow path of the magnetic fluid 40 (annular gaps 42, 52), and the pole portions 48a, 48b of the cores 48, 58,
Reference numerals 58a and 58b are in sufficient contact with the magnetic fluid 40, and the cores 48 and 58 and the annular gap (fluid flow path).
The magnetic fluid 40 in 42 and 52 and the cylindrical members 46 and 56 form a magnetic circuit.

Therefore, when the electromagnetic coils 49 and 59 are energized, a large magnetic field is generated with a small current by the annular gaps 42 and 5.
2 is applied to the magnetic fluid 40 in
A magnetic field is applied in a direction orthogonal to the direction of zero flow. Also, the magnitude of the applied magnetic field can be changed by changing the amount of current.

In FIGS. 3 and 4, 44 and 54 are annular spacers, which are made of a non-magnetic material. Further, a plurality of electromagnets 47 and 57 are arranged in the inner space 41 and the outer space 51, respectively, as in the case shown in FIG.

The pole portions 48a, 48b, 58a, 5 of the cores 48, 58 have a structure for applying such a magnetic field.
By making 8b project into the flow path (annular gaps 42, 52) of the magnetic fluid 40, it is possible to apply a sufficient magnetic field almost perpendicularly to the flow of the magnetic fluid 40 and at a number of locations ( Two places with one electromagnet).

Therefore, the flow rate of the magnetic fluid 40 can be controlled by changing the amount of electricity supplied to the electromagnetic coils 49, 59 by a relatively small current, thereby changing the viscosity of the magnetic fluid 40 and the magnetic force acting on the magnetic fluid 40. Therefore, the pressure difference generated between the inlet and the outlet of the flow path can be changed, and the damping force can be changed with a relatively small current.

On the other hand, the magnet poles 108 and 118 and the magnet pole 11
0, 120 poles 108a, 118a, 110b, 12
0b also projects into the flow path of the magnetic fluid 40 (annular gaps 42, 52), and the pole portions 108a, 118a, 110
b and 120b are in full contact with the magnetic fluid 40, and the permanent magnets 109 and 119 and the magnet poles 108 and
118, the magnet poles 110 and 120, the magnetic fluid 40 in the annular gaps (fluid flow paths) 42 and 52, the cylindrical member 46,
A magnetic circuit is formed by 56.

Between the magnet poles 108, 118, 110, 120 and the cylindrical members 46, 56, that is, the annular gap, the magnetic field by the permanent magnets 109, 119 is always applied.

By providing such a magnetic field application section using a permanent magnet, the physical properties of the magnetic fluid are changed to a state more suitable for flow control, so that the flow control effect can be enhanced (for details, refer to the above 1994 edition). See the specification of the applicant B).

As the material for the annular spacers 44 and 54, copper, non-magnetic metal such as austenitic stainless steel, polytetrafluoroethylene (trade name: Teflon) or the like can be used. Any other non-magnetic material may be used.

Further, the cylindrical member 46, which forms the magnetic circuit,
56, cores 48, 58 and magnet poles 108, 118, 1
In 10, 120, soft iron, Fe-Si alloy, Fe-Al
Any high-permeability material such as alloy, permalloy or mumetal can be used. And the core 48,
A ferrite core can be used for 58, and
Not limited to these, the electromagnets 47 and 57 having higher responsiveness can be obtained by using a high frequency magnetic material.

In the magnetic circuit according to the present invention,
The pole portions 48a, 48b, 58a, 58b of the cores 48, 58
Is directly in contact with the magnetic fluid 40 by protruding into the flow path (annular gaps 42, 52) of the magnetic fluid 40, so that a magnetic field of a certain magnitude or more can be applied to the magnetic fluid 40 with a smaller current. Become.

Further, the cylindrical members 46, 56 and the cores 48, 5
It is also convenient that there is a small gap between the two.

The core 4 is used for rust prevention and insulation.
In some cases, it may be necessary to coat 8,58, but the thickness of the coating layer at that time is at most 10
Since it is about μm or less, there is almost no difference in the current value.

Therefore, in the present invention, the core 4
The pole portions 48a, 48b, 58a, 58b of the magnets 8, 58 are projected into the flow path of the magnetic fluid 40, so that the magnetic fluid 4
Since it is in direct contact with 0, it is possible to apply a magnetic field of a certain magnitude or more to the magnetic fluid 40 with a small current.

As a concrete example of dimensions, the inner diameter of the housing 32 is 140 mm and the outer diameter of the cylindrical body 34 is 72 mm.
mm, and the width of the vane 34a can be 122 mm.

The cylindrical members 46 and 56 have a wall thickness of 2 mm.
Made of soft iron. Further, the annular cores 48, 58
In FIG. 4, Lc = 8 mm, g = 10 mm, a =
The electromagnets 47 and 57 were made to be 5 mm and h = 3 mm and made of soft iron and capable of sufficiently generating a magnetic field of 5 kOe. Further, the protrusion amount of the pole portions 48a and 48b of the core 48 is C ₁ = 1 mm, and the electromagnetic coil 49 can be relatively retracted by 1 mm.

The thickness of the annular spacers 44, 54 is s = 8 mm, and the amount of protrusion of the pole portions 48a, 48b, 58a, 58b from the annular spacers 44, 54 is C.
₂ = 2 mm, the annular spacers 44 and 54 are the pole portions 48.
It is made of polytetrafluoroethylene (trade name: Teflon) for pulling 2 mm from a, 48b, 58a, 58b, and two electromagnets 47 and 57 are arranged side by side as shown in FIG. At this time, the magnetic field is applied to a total of 8 points.

Further, the magnet poles 108, 118, 110, 1
20 can also be made of soft iron. In FIG. 4, Lm = 8 mm and a = 5 mm. Further, as the permanent magnets 109 and 119, ferrite magnets having a surface magnetic flux density of about 1 kG can be used. Furthermore, gm = 10m
It can be set that m and tm = 4 mm.

The size of the annular gaps 42 and 52 is b =
It can be 1 mm. In this case, the rotation speed is 10
It is a sufficiently laminar flow region even at 0 ° / sec.

With the above configuration, the magnetic fluid 4
Effective use of magnetic force as well as viscous force due to 0 magnetic field,
In addition, the rotary damping force variable type shock absorber 31 aiming at high efficiency
Can be

[0104]

However, in the magnetic fluid flow control mechanism used in the conventional damping force variable type shock absorbers and the like described above, when the magnetic field is generated by the electromagnet for generating the damping force. Since a large amount of power is consumed, there is always a potential demand for power saving, and it has been a problem to solve this problem and further improve efficiency.

[0105]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems of the prior art, and it is possible to generate a damping force of a desired magnitude with a relatively small electric power. It is another object of the present invention to further provide a damping force variable type shock absorber and a magnetic fluid flow control mechanism suitable for fluid flow control in this damping force variable type shock absorber and other devices.

[0106]

A magnetic fluid flow control mechanism suitable for a damping force variable type shock absorber according to the present invention uses a magnetic fluid as hydraulic oil and utilizes an increase in viscosity due to a magnetic field of the magnetic fluid. The effect of the magnetic force exerted on the magnetic fluid by the magnetic field is effectively utilized in a plurality of stages, and is the result of further diligent study of means for achieving high efficiency.

That is, the damping force variable type shock absorber according to claim 1 of the present invention uses a magnetic fluid as hydraulic oil, and is orthogonal to the flow direction of the magnetic fluid by an electromagnet in the flow path of the magnetic fluid. Or a plurality of sites to which a magnetic field is applied in a substantially orthogonal direction and to which the magnetic field is applied are formed in the direction of the flow of the magnetic fluid, and the pole portion of the core of the electromagnet at the site to which the magnetic field is applied is directly or a coating layer. Is in contact with the magnetic fluid in a state of being intervened by the magnetic field, and by utilizing the increase in the viscosity of the magnetic fluid due to the magnetic field and the action of the magnetic force exerted on the magnetic fluid in the magnetic field in a plurality of stages, In a damping force variable type shock absorber with a magnetic fluid flow control mechanism that causes a pressure difference in the magnetic field, concentrate the magnetic field on the pole part of the electromagnet core at the part to which the magnetic field is applied. The magnetic circuit is formed, and the cross-sectional area of the flow path in the portion to which the magnetic field is applied is uniform over the entire length of the electromagnet in the flow path direction while straddling the electromagnet, and each It is characterized in that a magnetic fluid pool is provided in the flow path between the electromagnet parts.

In the embodiment of the damping force variable type shock absorber according to claim 1 of the present invention, as claim 2,
A magnetic fluid is used as the hydraulic oil, and a flow path for the magnetic fluid that connects the rod side chamber and the piston side chamber in the cylinder in which the piston rod with the piston slides is provided. Applying a magnetic field in a direction orthogonal or substantially orthogonal to the direction of fluid flow and forming a plurality of sites to which the magnetic field is applied in the direction of flow of the magnetic fluid, the electromagnet of the site to which the magnetic field is applied is formed. The pole portion of the core is in contact with the magnetic fluid either directly or through a coating layer, utilizing the increase in viscosity of the magnetic fluid due to the magnetic field and utilizing the action of the magnetic force exerted on the magnetic fluid in the magnetic field in multiple stages. In the telescopic damping force variable type shock absorber having a magnetic fluid flow control mechanism for generating a pressure difference in the magnetic fluid flow path, A magnetic circuit that concentrates a magnetic field at the pole of the electromagnet core is formed at the site where the field is applied, and the cross-sectional area of the flow path at the site where the magnetic field is applied crosses the electromagnet and The length may be uniform over the entire length, and a magnetic fluid pool may be provided in the flow path between the electromagnet portions.

[0109] Similarly, in the embodiment, as claim 3, a magnetic fluid is used as the hydraulic oil, and the inside of the housing is partitioned by a fixed wall provided on the housing and a movable vane provided on the rotary shaft. And a magnetic fluid flow path communicating between the chambers is provided, and a magnetic field is applied to the magnetic fluid flow path by an electromagnet in a direction orthogonal to or substantially orthogonal to the flow direction of the magnetic fluid, and A plurality of portions for applying the magnetic field are formed in the flow direction of the magnetic fluid, and the pole portion of the core of the electromagnet in the portion for applying the magnetic field is in contact with the magnetic fluid directly or through a coating layer. By utilizing the increase in viscosity of the magnetic fluid due to the magnetic field and utilizing the action of the magnetic force exerted on the magnetic fluid by the magnetic field in multiple stages,
In a rotary damping force variable type shock absorber having a magnetic fluid flow control mechanism for generating a pressure difference in the flow path of the magnetic fluid, a magnetic circuit for concentrating a magnetic field at a pole portion of a core of an electromagnet at a portion to which the magnetic field is applied. And the cross-sectional area of the flow path in the part to which the magnetic field is applied is uniform over the entire length of the electromagnet in the flow path direction while straddling the electromagnet, and between the electromagnet parts. The channel may be configured to have a magnetic fluid reservoir.

According to the fourth aspect of the present invention, the flow of the magnetic fluid can be an annular clearance flow. In the same aspect, the fifth aspect of the present invention is the magnetic fluid flow control mechanism. And in an embodiment also:
As a sixth aspect, it is possible that the magnetic fluid reservoir is provided with a magnetic field applying section by a permanent magnet.

Further, a magnetic fluid flow control mechanism used for fluid flow control of a damping force variable type shock absorber and other equipment according to claim 7 of the present invention uses a magnetic fluid as hydraulic oil, A magnetic field is applied to the flow channel by an electromagnet in a direction orthogonal or substantially orthogonal to the flow direction of the magnetic fluid, and a plurality of sites to which the magnetic field is applied are formed in the flow direction of the magnetic fluid. The pole portion of the core of the electromagnet in a portion to which is applied is in contact with the magnetic fluid directly or through the coating layer, and the increase in viscosity of the magnetic fluid due to the magnetic field is utilized and the magnetic force exerted on the magnetic fluid by the magnetic field In the magnetic fluid flow control mechanism that causes a pressure difference in the flow path of the magnetic fluid by utilizing the action of A magnetic circuit for concentrating the magnetic field is formed at the poles of the core of the electromagnet, and the cross-sectional area of the flow path at the portion to which the magnetic field is applied straddles the electromagnet. The flow path between the electromagnet portions may be uniform and a pool of magnetic fluid may be provided.

Further, in an embodiment of the magnetic fluid flow control mechanism according to claim 7 of the present invention, as in claim 8, the flow of the magnetic fluid can be an annular gap flow. In claim 9, the present invention may be used for fluid flow control of a damping force variable type shock absorber, and in the same embodiment, as claim 10, the magnetic fluid reservoir may include a magnetic field applying part using a permanent magnet. Can be provided.

[0113]

In the variable damping force type shock absorber according to the first aspect of the present invention, a magnetic circuit for concentrating the magnetic field at the pole portion of the core of the electromagnet is formed at the portion to which the magnetic field is applied, thereby applying the magnetic fluid to the magnetic fluid. The value of the applied magnetic field is increased, the value of the magnetic field applied to the magnetic fluid is increased, and the efficiency is improved. In addition, the cross-sectional area of the flow path at the site where the magnetic field is applied was made uniform over the entire length of the electromagnet in the flow path direction while straddling the electromagnet. When the pole of the electromagnet core is flat (when the cross-sectional area of the flow path is uniform), the increase in pressure when the pole of the electromagnet core is projected is higher than that when the pole of the electromagnet is projected. This is because the increase is large. At this time, if all the cross-sectional areas of the flow path of the magnetic fluid are made uniform, there is a problem that the pressure increase reaches a peak at a large current flowing through the electromagnetic coil of the electromagnet, but a magnetic fluid pool is provided between the electromagnets. As a result, the peak of pressure increase is eliminated, and as a result, the efficiency of the flow control effect is improved, a relatively large desired damping force is generated with less electric power, and by changing the current value. It becomes a damping force variable type shock absorber in which the damping force changes greatly.

With the damping force variable type shock absorber according to the second aspect of the present invention, by adopting the above-mentioned configuration, it becomes a telescopic damping force variable type shock absorber having the same operation as described in the first aspect. .

According to the damping force variable type shock absorber according to claim 3 of the present invention, by adopting the above-mentioned configuration, it becomes a rotary type damping force variable type shock absorber having the same operation as described in claim 1. .

With the damping force variable type shock absorber according to claim 4 of the present invention, by adopting the above-mentioned configuration, the damping force variable type shock absorber can generate a relatively large desired damping force with less electric power. .

[0117]

With the damping force variable type shock absorber according to the fifth aspect of the present invention, by adopting the above configuration, it becomes a compact and highly practical damping force variable type shock absorber.

In the damping force variable type shock absorber according to the sixth aspect of the present invention, when the magnetic field application section by the permanent magnet is provided, the physical properties of the magnetic fluid change to a state more suitable for the flow control, so that the flow control effect is obtained. It becomes a variable damping force type shock absorber which generates a relatively large desired damping force with a higher power consumption and a lower power consumption.

In the magnetic fluid flow control mechanism according to claim 7 of the present invention, by adopting the above-mentioned structure, the magnetic fluid flow control mechanism with improved efficiency of the flow control effect can be obtained by the same action as in claim 1.

In the magnetic fluid flow control mechanism according to the eighth aspect of the present invention, with the above configuration, the magnetic fluid flow control mechanism is further improved in the efficiency of the flow control effect.

In the magnetic fluid flow control mechanism according to claim 9 of the present invention, by using the damping force variable type shock absorber,
A relatively large desired damping force is generated with a smaller amount of electric power, and a damping force variable shock absorber in which the damping force is greatly changed by changing the current value can be obtained.

In the magnetic fluid flow control mechanism according to the tenth aspect of the present invention, with the above configuration, the physical properties of the magnetic fluid are changed to a state more suitable for the flow control, and the efficiency of the flow control effect is further enhanced. It becomes a magnetic fluid flow control mechanism.

[0124]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 show the construction of the essential parts of a magnetic fluid flow control mechanism suitable for a telescopic or rotary damping force variable type shock absorber in one embodiment of the present invention. Here, FIG. And the magnetic fluid flow control mechanism 45 shown in FIGS. 11 and 12 which is an improvement of the magnetic fluid flow control mechanisms 45 and 55 provided in the flow path of the magnetic fluid 40 of the rotary damping force variable type shock absorber 31 shown in FIG. , 55 is further improved.

As shown in FIG. 1, the flow paths of the magnetic fluid are annular gaps 42 and 52 between the cylindrical members 146 and 156 and the electromagnets 47 and 57, and between the magnet poles 108 and 118. Has been formed. And electromagnets 47, 5
The cores 48 and 58 of No. 7 are annular and have a U-shaped cross section as shown. Cores 48, 5 of this electromagnet 47, 57
8 are provided with electromagnetic coils 49 and 59, respectively.

Further, the cylindrical members 146 and 156, the electromagnet 4
The cores 48 and 58 of 7, 57 are made of a high magnetic permeability material.

FIG. 2 is an enlarged view of the magnetic field applying portion by the electromagnet of FIG. 1, in which the cores 48 of the electromagnets 47 and 57,
The pole portions 48a, 48b, 58a, 58b of 58 are exposed in the flow paths (annular gaps 42, 52) of the magnetic fluid 40,
The pole portions 48a, 48b, 58a, 58b of the cores 48, 58
Is in sufficient contact with the magnetic fluid 40, and a magnetic circuit is formed by the cores 48 and 58, the magnetic fluid 40 in the annular gaps (fluid flow paths) 42 and 52, and the cylindrical members 146 and 156. .

These cylindrical members 146 and 156 have pole portions 48a and 48 of the cores 48 and 58 of the electromagnets 47 and 57, respectively.
b, 58a, 58b, pole portions 48c, 48d,
58c and 58d are formed. Also, 201, 211
Is a layer formed of a non-magnetic material.

By doing so, the magnetic field of the electromagnet can be concentrated on the poles. The action and effect will be described later.

When the electromagnetic coils 49, 59 are energized, a large magnetic field is applied to the magnetic fluid 40 in the annular gaps 42, 52 with a small current, and at this time, the magnetic fluid 40 is orthogonal to the flow direction. A magnetic field is applied in the direction.
Also, the magnitude of the applied magnetic field can be changed by changing the amount of current.

In FIG. 1 and FIG. 2, 44, 54, 1
44 and 154 are annular spacers, which are made of a non-magnetic material. Further, a plurality of electromagnets 47 and 57 are arranged in the inner space 41 and the outer space 51, respectively, as in the case shown in FIG.

The pole portions 48a, 48b, 58a, 5 of the cores 48, 58 have a structure for applying such a magnetic field.
8b and the pole portions 48c, 48 of the cylindrical members 146, 156
Since d, 58c, and 58d are in contact with the flow paths (annular gaps 42 and 52) of the magnetic fluid 40, they are substantially perpendicular to the flow of the magnetic fluid 40, and at many points.
A sufficient magnetic field can be applied (one electromagnet at two locations).

Therefore, the flow rate of the magnetic fluid 40 can be controlled by changing the amount of electricity supplied to the electromagnetic coils 49, 59 by a relatively small current, thereby changing the viscosity of the magnetic fluid 40 and the magnetic force acting on the magnetic fluid 40. Therefore, the pressure difference generated between the inlet and the outlet of the flow path can be changed, and the damping force can be changed with a relatively small current.

As shown in FIGS. 1 and 2, the cross sections of the magnetic fluid channels 42 and 52 in the electromagnet portion are assumed to be uniform over a length approximately twice the length of the electromagnet. is there.

Further, the annular spacers 144 and 154 are sufficiently retracted, and a sufficient volume is secured outside them. That is, magnetic fluid reservoirs 202 and 212 are provided.

The operation and effect of such a structure will be described later.

In addition, the annular spacers 44, 54, 14
As the material of 4,154, a non-magnetic metal such as copper or austenitic stainless steel, or a material such as polytetrafluoroethylene (trade name: Teflon) can be used. Of course, any non-magnetic material can be used. It can be anything.

Also, the cylindrical member 14 forming the magnetic circuit
6,156 and the cores 48, 58 may be made of any material having a high magnetic permeability such as soft iron, Fe-Si alloy, Fe-Al alloy, permalloy, and mumetal. Ferrite cores can be used for the cores 48 and 58, and the electromagnets 47 and 57 having higher responsiveness can be obtained by using not only the ferrite cores but also magnetic materials for high frequencies.

In the magnetic circuit of the present invention, the pole portions 48a, 48b, 58a, 58b of the cores 48, 58 and the pole portions 48c, 48d, 5 of the cylindrical members 146, 156 are arranged.
8c and 58d are flow paths of the magnetic fluid 40 (annular clearance 42,
Since it is exposed to 52), it is in direct contact with the magnetic fluid 40, so that a magnetic field of a certain magnitude or more can be applied to the magnetic fluid 40 with a smaller current.

Further, the cylindrical members 146 and 156 and the core 4 are
It is also convenient that there is a small gap between 8,58.

The core 4 is used for rust prevention and insulation.
In some cases, it is necessary to coat 8, 58 and the cylindrical members 146, 156, but since the thickness of the coating layer at that time is at most about 10 μm, there is almost no difference in the current value. Don't come

Therefore, in the present invention, the core 48,
The pole portions 48a, 48b, 58a, 58b of 58 are in direct contact with the magnetic fluid 40 because they are exposed in the flow path of the magnetic fluid 40, and a magnetic field of a certain magnitude or more can be magnetized with a small current. It can be applied to the fluid 40.

By the way, since it was not possible to know from the literature how the flow of the magnetic fluid 40 can be controlled by the magnetic field under the flow of the fluid as in the present invention, further description will be given here. A new basic examination was tried by an experiment.

Before describing them in detail, what is described in the specification of the above-mentioned application filed in 1994, the findings obtained so far will be roughly described. This is because it provides the necessary background to explain the subject matter of the present invention.

As shown in FIG. 13, when the radius is R and the annular clearance is b, and the length is L when the fluid having the viscosity η is flowed by the flow rate Q, the pressure difference Δp generated at both ends is expressed by the following equation 1
Given in.

[0147]

[Formula 1] However, D = 2R.

This equation is for the case where the fluid flow is an annular clearance flow, and is described in, for example, Toshio Sato, "Actual Design of Hydraulic Systems", Ohga Shuppan (1970), page 47.

From this equation, it can be considered that a pressure difference is generated based on the viscosity of the fluid.

On the other hand, the pressure increase due to the magnetic force is

[0151]

[Formula 2] Given in. See, for example, Taketomi and Chikaku, "Magnetic Fluid Fundamentals and Applications," Nikkan Kogyo Shimbun (1988), page 25.

Here, H is the magnitude of the magnetic field acting on the magnetic fluid, and M is the magnetization of the magnetic fluid. And
The right side of Expression 2 corresponds to the area under the magnetization curve shown in FIG. 14 described later.

Here, the magnitude of the pressure difference Δp due to the magnetic force will be evaluated. Assuming that the magnetic fluid has a magnetization (flux density) of 300 G (Gauss) in a magnetic field of 5 kOe, 0.03 [T] × 5 × 10 ³ × 79.6 [A / m] = 11.9 × 10 ³ TA /M=11.9 kPa = 0.1
Estimated to be 2 atm. That is, a pressure increase of about 0.1 atm can be expected.

This increase in pressure becomes a resistance to flow. Therefore, it can be expected that pressure will be generated by the magnetic force. Providing a large number of locations for applying a magnetic field makes it possible to expect a multi-step effect, and it becomes possible to generate a large pressure.

As shown in FIG. 5A, two annular cores 48 facing inward are arranged side by side to form an annular gap 42 with the cylindrical member 46, and the flow characteristics have been experimentally understood. .

The pressure difference was obtained by measuring the pressure at both ends using the flow rate Q, that is, the flow velocity in the annular gap 42 as a parameter. At this time, the values of R and b in FIG. 13 are R = 10 mm and b = 0.45, respectively.
mm.

The annular core 48 is made of PB permalloy, and the dimensions are indicated by the symbols in FIG.
c = 4 mm, g = 7 mm, h = 6 mm, a = 10 mm.

The spacer 44 was made of polytetrafluoroethylene (Teflon). The inner cylindrical member 46 has a solid Fe-13 wt% Al shaft (diameter 19.1).
mm) was used.

As the electromagnetic coil 49, an enameled wire having a wire diameter of 0.5 mm was used and the number of turns was 50 turns.

The experiment was mainly carried out using a water-based magnetite magnetic fluid W40 manufactured by Taiho Industry Co., Ltd.
The iron nitride magnetic fluid A (where A is a symbol for identifying the sample) was also examined. The iron nitride magnetic fluid A was newly synthesized and manufactured.

The pressure difference between both ends when no magnetic field was applied was in agreement with the theoretical value (Equation 1).

Next, the increase in pressure when a magnetic field was applied was examined. In the water-based magnetite magnetic fluid W40, about 0.05 at a magnetic field of about 5 kOe per step.
It was an increase of kgf / cm ² .

It was also possible to confirm the effect in multiple stages.

On the other hand, with the iron nitride magnetic fluid A, in an experiment under the same conditions, about 0.1 kgf / cm ² per step
The pressure was increasing. The saturation magnetization (saturation magnetic flux density) of this iron nitride magnetic fluid A was about 320 G (Gauss). That is, in the iron nitride magnetic fluid, the pressure increases almost as expected.

Next, the magnetic characteristics of the magnetic fluid will be described.

FIG. 14 shows the measurement results of the DC magnetic characteristics of the iron nitride magnetic fluid B and the water-based magnetite magnetic fluid W40 at room temperature. FIG. 14 shows the results of measurement by a vibrating magnetometer (VSM), in which the horizontal axis is the effective magnetic field (Heff) and the vertical axis is 4πI.

Further, in order to compare the rising of the magnetization, the magnetization at about 10 kOe is regarded as the saturation magnetization, and the saturation magnetization is standardized in FIG.

As shown in FIGS. 14 and 15, it can be seen that in the iron nitride magnetic fluid, the rising of the magnetization curve is steep. And with iron nitride magnetic fluid, 600 Oe
While the effective magnetic field (Heff) causes 90% magnetization,
The water-based magnetite magnetic fluid W40 requires a magnetic field of 4.4 kOe to achieve 90% magnetization.
You can see from 5.

The fact that the particle magnetization of the iron nitride fine particles is larger than the particle magnetization of the magnetite fine particles and that the particle diameters are well aligned are the reasons why the magnetization curve of the iron nitride magnetic fluid rises sharply. Is interpreted as

The magnetic characteristics of the magnetic fluid will be described from a viewpoint different from the above.

FIG. 16 shows the DC magnetic characteristics of the iron nitride magnetic fluid A'and the water-based magnetite magnetic fluid W40 at room temperature measured by a vibrating magnetometer (VSM). In FIG. 16, the horizontal axis represents the external magnetic field (He
x), and the vertical axis is shown normalized by the magnetization at 5 kOe in order to compare the rising of the magnetization. in this case,
The magnetization at 5 kOe is considered to be saturation magnetization.

As shown in FIG. 16, in the iron nitride magnetic fluid, the rising of the magnetization curve is steep.
And, while the iron nitride magnetic fluid is 90% magnetized by an external magnetic field (Hex) of 280 Oe, the water-based magnetite magnetic fluid W40 requires a magnetic field of 2.5 kOe to be 90% magnetized. Recognize.

As described above, the particle magnetization of iron nitride fine particles is larger than the particle magnetization of magnetite fine particles,
It is interpreted that the fact that the particle diameters are well aligned with each other is the reason why the magnetization curve of the iron nitride magnetic fluid rises steeply.

Such a steep rise of the magnetization curve can be represented by a difference in initial magnetic permeability.

The specific initial magnetic permeability obtained from the BH curve measured by filling the magnetic fluid in a toroidal core-shaped container is 17 for the iron nitride magnetic fluid B, and the water-based magnetite magnetic fluid W.
It was 4 at 40.

Hereinafter, the relative initial magnetic permeability will be simply referred to as magnetic permeability.

By the way, as described above, it is desirable that the damping force variable type shock absorber has a low power consumption and a high efficiency.

Therefore, a more intensive study was made on a method for improving efficiency.

At that time, it was noticed that the value of the magnetic field applied to the magnetic fluid was increased by concentrating the magnetic field of the electromagnet.

That is, it is considered that the higher the value of the magnetic field applied to the magnetic fluid, the higher the efficiency.

Therefore, it was decided to confirm the effect by experiments.

The experiment was first carried out using the water-based magnetic fluid W40.

As shown in FIG. 5A, a comparison was made between the case where two electromagnets are arranged and the case where the cylindrical member is changed to that according to the present invention, as shown in FIG. 5B.

First, FIG. 5A shows the dimensional relationship.

Although overlapping with the above, the values of R and b in FIG. 13 are R = 10 mm and b = 0.4, respectively.
It was set to 5 mm.

The annular core 48 is made of PB permalloy, and the dimensions are indicated by the symbols in FIG.
c = 4 mm, g = 7 mm, h = 6 mm, a = 10 mm. Also, s = 10 mm and 30 mm. Note that C
1 = 0 mm and C2 = 0 mm.

The spacer 44 is made of polytetrafluoroethylene (Teflon). Also, as shown in the figure on both sides, s
A spacer 44 of 10 mm and s = 30 mm was arranged.
The inner cylindrical member 46 contains solid Fe-13 wt% Al.
A manufactured shaft (diameter 19.1 mm) was used.

The electromagnetic coil 49 has a wire diameter of 0.5 m.
An enameled wire of m was used and the number of turns was 50.

FIG. 6A is a plot of the pressure increase when two electromagnets are energized against the current.

Next, the same measurement was tried with the setting of FIG. 5 (b).

A solid Fe-13% by weight Al shaft was used for the cylindrical member 146 of FIG. 5B. As shown in the figure, only the facing portion of the pole of the electromagnet has a diameter of 19.1 mm.
The protrusion length was 4 mm, which was the same as the pole length of the core. The diameter of the shaft other than that is 17.1 mm.
Then, cover the part with an adhesive and harden it, and set the outer diameter to 19.1.
The finished shaft was made into mm to obtain the illustrated shaft. Araldite was used as the adhesive. The same electromagnets and spacers as in FIG. 5A were used.

Therefore, the dimensional relationship between the annular gaps is exactly the same in FIGS. 5 (a) and 5 (b).

In FIG. 5B, the increase in pressure when two electromagnets are energized is plotted against the current, which is shown in FIG. 6B.

In (b) of FIG. 6 (A), the increase in pressure has reached a peak when the current is large. In addition, in the region where the current is small, the pressure increases by about 50% compared to (a).

That is, it was found that the efficiency can be increased by about 50% by concentrating the magnetic field of the electromagnet by devising a magnetic circuit as shown in FIG. 5B.

Further, in FIG. 5A, the magnetic field is still large below the pole of the electromagnet, but it has a broad distribution.

Further, as shown in FIG. 5B, when a protrusion is provided on the cylindrical member, the magnetic field concentrates on the pole of the electromagnet.
As a result, it is considered that the magnitude of the magnetic field applied to the magnetic fluid is increasing.

The actual magnetic field distribution and the magnitude of the magnetic field were not measured here.

Next, in FIG. 5 (b), the pressure increase reaches a peak when the current is large (FIG. 6).
(Refer to (b) in (A)) The reason was examined.

At large currents, the magnetic field also increases accordingly. Then, clusters of magnetic particles are formed under the magnetic poles of the electromagnet, but as shown in FIG.
Since the annular clearance between the electromagnets is a closed space and has a small volume, the supply of magnetic fine particles becomes insufficient.

Therefore, it is estimated that the increase in pressure will reach the ceiling.

To confirm this, a magnetic fluid reservoir 202 was provided between the electromagnets as shown in FIG. 5 (c).

In FIG. 5 (c), only the spacer in the middle of FIG. 5 (b) is changed to use two 10 mm spacers and a 10 mm spacer retracted by 6 mm.

Then, FIG. 6 (b) is a plot of the amount of pressure increase when the two electromagnets are energized against the current. It can be seen that the results are as discussed above.

Incidentally, the alternate long and short dash line in FIG.
It is a trace of the result of (b) in (A).

As described above, the magnetic fluid pool 2 is formed between the electromagnets.
It was found that the provision of 02 can eliminate the peak pressure increase.

From the results of the above experiments, it is possible to improve efficiency by about 50%.

Next, the same experiment was tried using the iron nitride magnetic fluid A.

The results were almost the same as with the water base.

By the way, in FIG. 5C, the cross-sectional area of the annular clearance channel is uniform. Further, the length of the uniform flow path portion is set to be about twice the length of the electromagnet.

The reason for doing so will be described below.

A detailed comparison was made on the amount of pressure increase in the case of the salient pole shown in FIG. 11 and in the case of a flat surface as shown in FIG.

Here, an example of the result is shown in FIG. 7 is a flat case, and Δ in FIG. 7 is a projecting pole.

The detailed experimental conditions for obtaining the results shown in the figure will be omitted.

In the case of the salient pole, the increase in pressure when the current is small is better than in the case where the current is flat, but it is better when the current is large in the case where the current is flat.

That is, the ultimate pressure increases more when the pressure is flat.

Therefore, here, the increase in the final ultimate pressure is emphasized, and the flat one is selected. By the way,
In the case of (c), it was also examined what happens if the length of the uniform flow path portion is further shortened.

As a result, it was found that when the length of the electromagnet was set to about 1.5 times, the behavior was similar to that of the protruding pole (see FIG. 7).

Therefore, the length of the uniform flow path portion is required to be about twice as long or longer.

The magnetic fluid flow control mechanism designed based on the above basic examination is suitable for the retractable or rotary damping force variable type shock absorber having the structure shown in FIGS. 1 and 2 described above. . Then, this was incorporated into the rotary damping force variable type shock absorber 31 shown in FIGS.

In this case, the inner diameter of the housing 32 is set to 140
mm, the outer diameter of the cylindrical body 34 is 72 mm, and the vane 3
The width of 4a was 122 mm.

The cylindrical members 146 and 156 have a wall thickness of 3
mm soft iron, and in FIG. 2, Ly = 7 m
m and d = 1 mm. The layers 201 and 202 were made of resin. Specifically, it is hardened with Araldite, which is an adhesive,
The inner surface has a smooth finish.

In addition, the annular cores 48 and 58 are, in FIG. 2, Lc = 7 mm, g = 8 mm, a = 5 mm, h = 3 m.
The electromagnets 47 and 57 are made of soft iron and are capable of sufficiently generating a magnetic field of 5 kOe.

The annular spacers 44 and 54 have a thickness of s2 = 10 mm, and the annular spacer 14
4,154 has a thickness of s1 = 14 mm, and e = 2
mm.

Annular spacers 44, 54, 144, 154
Was made of polytetrafluoroethylene (trade name: Teflon).

Further, as shown in FIG. 1, two electromagnets 47 and 57 are arranged side by side. At this time, the magnetic field is applied to a total of eight places.

The size of the annular gaps 42 and 52 is b =
It was set to 1 mm. In this case, the rotation speed is 100 ° / sec
It is also a sufficiently basin.

With the above configuration, the magnetic fluid 4
Effective use of magnetic force as well as viscous force due to 0 magnetic field,
In addition, the rotary damping force variable type shock absorber 31 aiming at high efficiency
Can be

FIGS. 1 and 2 and FIGS. 19 and 2
In the rotary damping force variable type shock absorber 31 shown in FIG. 0, the performance when the iron nitride magnetic fluid A is used as the magnetic fluid 40 is shown by a triangle mark in FIG.

At this time, as described above, the saturation magnetization (saturation magnetization density) was about 320G.

In FIG. 8, the horizontal axis is the rotation speed [deg / sec] of the rotary shaft 32a, and the vertical axis is about 5 kOe for both the case where no magnetic field is applied by the electromagnet and the case where all electromagnets are used.
Damping force when the magnetic field is
-M] difference.

The magnetic field of about 5 kOe referred to here is
This means that the current value gives the value of the magnetic field when no measures are taken to concentrate the magnetic field as in the present invention. The value of the magnetic field under the actual electromagnet pole should be larger.

As is clear from FIG. 8, when the iron nitride magnetic fluid A is used, the variable width is about 2.8 kgf · m. It goes without saying that the damping force within this width can be obtained by adjusting the amount of current.

Next, the saturation magnetization is about 3 of that of the iron nitride magnetic fluid A.
The performance was examined by using the doubled iron nitride magnetic fluid C as the magnetic fluid 40.

This result is also shown by a circle in FIG.

The variable width was about 8.5 kgf · m, and it was confirmed that the damping force could be adjusted to a greater extent.

From the above performance test results, in the rotary damping force variable type shock absorber 31 according to the present invention, it is possible to obtain the same performance as two electromagnets (four in total) and three electromagnets (six in total). I understood. That is, power saving of 2/3 has been achieved.

By the way, as in the application filed in 1994, the power saving can be achieved by providing the magnetic field applying section with the permanent magnet.

The configuration of FIG. 9 is the same as that of FIGS. 1 and 2 with respect to the electromagnets, etc.
2, 212 are provided with a magnetic field application section by a permanent magnet.

The structure of the magnetic field applying section is such that the annular magnets 109, 1
19 and annular magnet poles 108, 118, 1 having an L-shaped cross section
It is composed of 10, 120, 111, 121, 112, 122.

In the middle one, two annular magnet poles 108 and 118 having an L-shaped cross section and magnet poles 110 and 120 are combined to form a yoke.

On the left and right sides, one annular magnet pole 111, 121, 112, 122 each having an L-shaped cross section forms a yoke.

The ring-shaped magnets 109 and 119 are magnetized in the radial direction.

In the symbol of FIG. 4, Lm is set to 2 mm, the magnet pole and the magnet are retracted by 1 mm from the electromagnet pole, and the magnet is a ferrite magnet having a surface magnetic flux density of about 1 kG. The performance of the mold shock absorber 31 was examined.

As a result, the same performance as in FIG. 8 could be achieved with a sufficient margin.

The degree of further power saving evaluated from the current value of the electromagnet required to obtain the same performance as in FIG. 8 was about 30%.

That is, the magnetic fluid pools 202, 212
If a magnetic field application section with a permanent magnet is installed in the
The efficiency will be improved.

FIG. 10 shows an example of the construction of a magnetic field applying section using another permanent magnet.

In this case, 109 and 119 are annular permanent magnets magnetized in the axial direction, and 108, 118 and 11
Reference numerals 0 and 120 are annular magnet poles.

The permanent magnets 109 and 119 have gm (see FIG. 4) of 8 mm and 4 mm (left and right magnets) and tm of 2 m.
m, a performance of the rotary damping force variable shock absorber 31 was examined by using a ferrite magnet having a surface magnetic flux density of about 1 kG.

At this time, the annular magnet poles 108, 118, 1
Nos. 10 and 120 were retracted by 1 mm from the electromagnet pole as shown in the figure.

The performance of this configuration was almost the same as that of the configuration of FIG.

As can be seen from the above performance test results, the iron nitride magnetic fluid can easily achieve a magnetic fluid having a large saturation magnetization, so that the magnetic force can be effectively utilized (see Formula 2). ).

Further, as can be seen from the magnetization curves of FIGS. 14, 15 and 16, since the magnetic permeability is large, it is easily magnetized with a small magnetic field, which also makes the use of magnetic force extremely effective.

If the saturation magnetization (magnetic flux density) of the magnetic fluid 40 is about 300 G (Gauss) or more and the magnetic permeability is about 10 or more, the magnetic fluid 40 is not limited to the iron nitride magnetic fluid, and the same applies to other magnetic fluids. Needless to say, the effect of can be obtained.

The iron nitride magnetic fluid used in the above examples and the like was synthesized by the gas phase liquid phase reaction method. That is, after dissolving iron carbonyl Fe (CO) ₅ and polybutenyl succinimide in a normal paraffinic solvent, while blowing ammonia gas, 80 to 12
The mixture is heated to about 0 ° C. and reacted to produce an iron ammine carbonyl compound. The iron ammine carbonyl compound was decomposed by further heating this at a high temperature of 120 ° C. or higher to obtain an iron nitride magnetic fluid.

Furthermore, in the above-described embodiment, the case where the present invention is applied to the rotary damping force variable type shock absorber shown in FIGS. 19 and 20 has been described. However, the telescopic damping force variable type shock absorber shown in FIGS. 17 and 18 has been described. It goes without saying that it can also be applied to a shock absorber.

Furthermore, although the magnetic fluid flow control mechanism according to the present invention has been described as being applied to a damping force variable type shock absorber, it can also be applied to fluid flow control in other devices.

[0259]

As described above, according to the damping force variable type shock absorber according to the first aspect of the present invention, the magnetic fluid is used as the hydraulic oil, and the magnetic field is formed by the electromagnet in the flow path of the magnetic fluid. Applying a magnetic field in a direction orthogonal or substantially orthogonal to the direction of fluid flow and forming a plurality of sites to which the magnetic field is applied in the direction of flow of the magnetic fluid, the electromagnet at the site to which the magnetic field is applied. The pole portion of the core is in contact with the magnetic fluid either directly or through the coating layer, and the increase in viscosity of the magnetic fluid due to the magnetic field is utilized and the action of the magnetic force exerted on the magnetic fluid by the magnetic field is utilized in multiple stages. As a result, in a damping force variable type shock absorber having a magnetic fluid flow control mechanism that causes a pressure difference in the flow path of the magnetic fluid, in the damping force variable type buffer, (A) A magnetic circuit for concentrating a magnetic field is formed in the pole part, and the cross-sectional area of the flow path in the part to which the magnetic field is applied spans the electromagnet and extends over the entire length of the electromagnet in the flow path direction. Since the flow path between each electromagnet section is made uniform and the magnetic fluid pool is provided, the efficiency of the flow control effect can be increased, and as a result, a relatively large desired power consumption can be achieved with less electric power. It is possible to obtain a damping force variable shock absorber having a variable damping force and a large damping force by changing the current value.

According to the second aspect of the present invention,
The effect that a telescopic damping force variable type shock absorber having the same effect as described in claim 1 can be obtained.

According to the third aspect of the present invention,
The effect that the rotary damping force variable type shock absorber having the same effect as described in claim 1 can be obtained.

According to the fourth aspect of the present invention,
The effect is that a damping force variable shock absorber that generates a relatively large desired damping force can be obtained with less power.

[0263]

According to the fifth aspect of the present invention,
It is possible to reduce the size and obtain the effect that the damping force variable type shock absorber having high practicality can be obtained.

According to the configuration of claim 6 of the present invention,
By providing a magnetic field application unit with a permanent magnet, the physical properties of the magnetic fluid are changed to a state more suitable for flow control, which makes it possible to further enhance the flow control effect. A damping force variable shock absorber capable of generating a damping force is obtained.

According to the magnetic fluid flow control mechanism of the seventh aspect of the present invention, the magnetic fluid flow control capable of improving the efficiency of the flow control effect by the same effect as the damping force variable type shock absorber of the first aspect. The effect that the mechanism is obtained is brought about.

According to the eighth aspect of the present invention,
Further, it is possible to obtain an effect that a magnetic fluid flow control mechanism having a further improved flow control effect efficiency is obtained.

[0268]

According to the structure of claim 9 of the present invention,
By using the damping force variable type shock absorber, a relatively large desired damping force can be generated with less electric power, and the damping force variable type shock absorber can be greatly changed by changing the current value. The effect that a container is obtained is brought about.

According to the tenth aspect of the present invention, the physical properties of the magnetic fluid can be changed to a state more suitable for the flow control, and a magnetic fluid flow control mechanism having a higher efficiency of the flow control effect can be obtained. The effect of being given is brought.

[Brief description of drawings]

FIG. 1 is an explanatory cross-sectional view of a magnetic fluid flow control mechanism according to an embodiment of the present invention.

FIG. 2 is an enlarged explanatory diagram of a magnetic field application unit of the magnetic fluid control mechanism shown in FIG.

FIG. 3 is a cross-sectional explanatory view of a magnetic fluid flow control mechanism in the second application filed in 1994.

FIG. 4 is an enlarged explanatory view of a magnetic field applying portion of the magnetic fluid flow control mechanism shown in FIG.

FIG. 5 is a basic explanatory diagram of a conventional example ((a) of FIG. 5) and an example of the present invention ((b) of FIG. 5 and (c) of FIG. 5) showing a specific configuration of the annular gap.

FIG. 6 is a graph showing an experimental result in which the pressure increase is plotted against the current in FIG.

FIG. 7 is a graph showing the experimental results in which the pressure increase is plotted against the current when the annular gap has a uniform flow passage cross section and when only the poles of the electromagnets protrude into the flow passage (the annular gap is the same. ).

8 is a graph showing damping force characteristics when the magnetic fluid control mechanism shown in FIG. 1 is incorporated into the rotary damping force variable shock absorber shown in FIGS. 19 and 20. FIG.

FIG. 9 is a sectional view showing a magnetic fluid flow control mechanism according to another embodiment of the present invention.

FIG. 10 is a sectional view showing a magnetic fluid flow control mechanism according to still another embodiment of the present invention.

FIG. 11 is a cross-sectional explanatory view of a magnetic fluid flow control mechanism in the application A already filed in 1994.

12 is an enlarged explanatory view of a magnetic field applying portion of the magnetic fluid flow control mechanism shown in FIG.

FIG. 13 is an explanatory diagram of an annular clearance.

FIG. 14 is a graph showing measurement results of DC magnetic characteristics of iron nitride magnetic fluid B and water-based magnetite magnetic fluid W40 at room temperature.

FIG. 15 is a graph showing a magnetization curve in which the vertical axis of FIG. 14 is normalized by saturation magnetization.

FIG. 16 is a graph showing measurement results of DC magnetic characteristics of iron nitride magnetic fluid A ′ and water-based magnetite magnetic fluid W40 at room temperature.

FIG. 17 is a vertical cross-sectional explanatory view of a telescopic damping force variable type shock absorber in the application filed in 1993.

FIG. 18 is an enlarged explanatory view of a magnetic field applying portion of the expansion / contraction damping force variable type shock absorber shown in FIG. 17.

FIG. 19 is a vertical cross-sectional explanatory view of a rotary damping force variable shock absorber in the application filed in 1993.

20 is a cross-sectional view taken along the line AA of the rotary damping force variable type shock absorber shown in FIG.

FIG. 21 is an enlarged explanatory diagram of a magnetic field applying portion of the rotary damping force variable type shock absorber shown in FIG. 19.

FIG. 22 is a vertical cross-sectional explanatory view of a magnetic fluid flow control mechanism separately installed from the damping force variable type shock absorber.

23 is an enlarged explanatory diagram of a magnetic field applying portion of the magnetic fluid flow control mechanism shown in FIG.

[Explanation of symbols]

1 Telescopic variable damping force buffer 2 cylinders 2a Rod side chamber 2b Piston side chamber 3 piston rod 4 pistons 5 Magnetic fluid flow path 10 Magnetic fluid (hydraulic oil) 15 Magnetic fluid flow control mechanism 16 High permeability member (cylindrical member) 17 Electromagnet 18 core 18a, 18b core poles 19 electromagnetic coil 31 Rotational damping force variable shock absorber 32 housing 32a rotating shaft 32c interior wall 33 fixed axis 34a vane 35a, 35b rooms 37, 38, 39 Magnetic fluid flow paths 40 Magnetic fluid (hydraulic oil) 42,52 annular gap (flow path for magnetic fluid) 44, 54 spacer 45,55 Magnetic fluid flow control mechanism 46,56 High magnetic permeability member (cylindrical member) 47,57 electromagnet 48,58 core 48a, 48b, 58a, 58b core poles 48c, 48d, 58c, 58d The pole part of the cylindrical member 49, 59 electromagnetic coil 70 Magnetic fluid 71 Magnetic fluid flow path 75 Magnetic fluid flow control mechanism 82,92 annular gap (flow path for magnetic fluid) 86,96 High magnetic permeability member (cylindrical member) 87,97 Electromagnet 88,98 core 88a, 88b, 98a, 98b Core pole 89,99 electromagnetic coil 108, 118, 110, 120 annular magnet poles 109,119 Permanent magnet 111,121,112,122 annular magnet poles 144,154 spacer 146,156 Cylindrical member 201, 211 resin layer 202,212 Magnetic fluid pool

─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Tatsuo Sugiyama 2 Takara-cho, Kanagawa-ku, Yokohama-shi, Kanagawa Nissan Motor Co., Ltd. (56) Reference JP-A-6-272732 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) F16F 9/00-9/58

Claims (10)

(57) [Claims] 1. A magnetic fluid is used as hydraulic oil, and a magnetic field is applied to a flow path of the magnetic fluid by an electromagnet in a direction orthogonal or substantially orthogonal to the flow direction of the magnetic fluid, and the magnetic field is applied. A plurality of portions are formed in the flow direction of the magnetic fluid, and the pole portion of the core of the electromagnet in the portion to which the magnetic field is applied is in contact with the magnetic fluid directly or through the coating layer, A damping force provided with a magnetic fluid flow control mechanism that causes a pressure difference in the flow path of the magnetic fluid by utilizing the increase in viscosity due to the magnetic field and utilizing the action of the magnetic force of the magnetic field on the magnetic fluid in multiple stages. In the variable shock absorber, a magnetic circuit for concentrating the magnetic field is formed at the pole portion of the core of the electromagnet at the portion to which the magnetic field is applied, and the magnetic field is applied. The cross-sectional area of the flow path at the part of the electromagnet is uniform over the entire length of the electromagnet in the flow direction, and a magnetic fluid pool is provided in the flow path between the electromagnet parts. A damping force variable type shock absorber characterized by being present. 2. A magnetic fluid is used as the hydraulic oil, and a magnetic fluid flow path is provided to connect a rod side chamber and a piston side chamber in a cylinder in which a piston rod provided with a piston slides. , Applying a magnetic field in a direction orthogonal to or substantially orthogonal to the flow direction of the magnetic fluid by an electromagnet and forming a plurality of sites in the flow direction of the magnetic fluid to which the magnetic field is applied, and applying the magnetic field The pole portion of the core of the electromagnet in the portion is in contact with the magnetic fluid directly or through the coating layer, and the increase in viscosity of the magnetic fluid due to the magnetic field is utilized and the action of the magnetic force on the magnetic fluid in the magnetic field is exerted. A telescopic damping force variable type shock absorber equipped with a magnetic fluid flow control mechanism that causes a pressure difference in the flow path of the magnetic fluid by using it in multiple stages. In the magnetic field is applied to the pole portion of the core of the electromagnet in the portion to which the magnetic field is applied, and the cross-sectional area of the flow path in the portion to which the magnetic field is applied crosses the electromagnet. The damping force variable type according to claim 1, wherein the length is uniform over the entire length in the flow path direction, and a magnetic fluid pool is provided in the flow path between the electromagnet parts. Shock absorber. 3. A magnetic fluid is used as hydraulic oil, and a chamber partitioned by a fixed wall provided on the housing and a movable vane provided on a rotary shaft is provided in the housing, and the magnetic communication between the chambers is provided. A magnetic fluid flow path, wherein a magnetic field is applied to the magnetic fluid flow path by an electromagnet in a direction orthogonal or substantially orthogonal to the flow direction of the magnetic fluid, and the magnetic field is applied to a portion of the magnetic fluid. A large number of points are formed in the direction of flow, and the pole portion of the core of the electromagnet in the portion to which the magnetic field is applied is in contact with the magnetic fluid either directly or through the coating layer, and the increase in viscosity of the magnetic fluid due to the magnetic field is used. In addition, a magnetic fluid flow control mechanism for producing a pressure difference in the flow path of the magnetic fluid is provided by using the action of the magnetic force of the magnetic field exerted on the magnetic fluid in multiple stages. In the rotating damping force variable type shock absorber, a magnetic circuit for concentrating the magnetic field at the pole portion of the core of the electromagnet is configured at the portion to which the magnetic field is applied,
The cross-sectional area of the flow path in the portion to which the magnetic field is applied is uniform over the entire length of the electromagnet in the flow path direction while straddling the electromagnet, and the flow path between the electromagnet parts has a magnetic fluid. The damping force variable type shock absorber according to claim 1, wherein a buffer is provided. 4. The damping force variable shock absorber according to claim 1, wherein the flow of the magnetic fluid is an annular clearance flow. A damping force variable shock absorber according to any one of items 1 to 4. 5. The damping force variable type shock absorber according to claim 1, wherein a magnetic fluid flow control mechanism is integrally incorporated. 6. The damping force variable type shock absorber according to claim 1, wherein the magnetic fluid reservoir is provided with a magnetic field applying section by a permanent magnet. 7. A magnetic fluid is used as hydraulic fluid, and a magnetic field is applied to the flow path of the magnetic fluid by an electromagnet in a direction orthogonal or substantially orthogonal to the flow direction of the magnetic fluid, and the magnetic field is applied. A plurality of portions are formed in the flow direction of the magnetic fluid, and the pole portion of the core of the electromagnet in the portion to which the magnetic field is applied is in contact with the magnetic fluid directly or through the coating layer, In the magnetic fluid flow control mechanism for producing a pressure difference in the flow path of the magnetic fluid by utilizing the increase in viscosity due to the magnetic field and utilizing the action of the magnetic force of the magnetic field on the magnetic fluid in a plurality of stages, A magnetic circuit for concentrating a magnetic field at the pole portion of the core of the electromagnet is configured at the applied portion, and the cross-sectional area of the flow path at the portion to which the magnetic field is applied is formed. Magnetic fluid flow characterized by being uniform over the entire length of the electromagnet in the flow path direction and straddling the electromagnet, and a magnetic fluid pool is provided in the flow path between the electromagnet parts. Control mechanism. 8. The magnetic fluid flow control mechanism according to claim 7, wherein the flow of the magnetic fluid is an annular clearance flow. 9. The magnetic fluid flow control mechanism according to claim 7, which is used for fluid flow control of a damping force variable shock absorber. 10. The magnetic fluid flow control mechanism according to claim 7, wherein the magnetic fluid reservoir is provided with a magnetic field applying section using a permanent magnet.