JP2003335164A - Vehicular seat suspension - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a seat suspension arranged between a vehicular seat and a body of a vehicle for supporting the seat in a vibration-proof manner, achieving lower transmissibility during idling while maintaining damping performance during travelling. <P>SOLUTION: The seat suspension comprises a seat side mounting bracket 12, a body side mounting bracket 14, a rubber elastic body 16 provided between both brackets, a piston member 18 and a cylinder member 20 joined to each other via the elastic body and relatively displaceable in the direction of vibration with the elastic deformation of the elastic body during vibration, a MR fluid 22 having viscosity changed with the strength of a magnetic field, a flow path 24 formed between the piston member 18 and the cylinder member 20 for sealingly holding the MR fluid 22 in a fluidized condition, and an electric magnet 26 for forming a magnetic path crossing the flow path and allowing the control of the strength of the magnetic field to change the viscosity of the MR fluid 22. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seat suspension arranged between a vehicle seat such as an automobile and a vehicle body to support the seat in a vibration-proof manner.

[0002]

2. Description of the Related Art Generally, seats for vehicles such as automobiles are
A seat pad made of a resin foam molding such as polyurethane foam and a seat frame having a spring on the receiving surface for receiving the seat pad are combined, and the surface is covered with a cover. When mounting such a vehicle seat on the floor in the passenger compartment, in an automobile, particularly a passenger car, the seat frame is supported on the floor in the passenger compartment via a seat suspension made of a rigid body, that is, the seat frame is attached to the floor. It is installed in a completely fixed state.

[0003]

By the way, in the vehicle seat, it is possible to prevent the slight vibration due to the idling of the engine from being transmitted from the floor to the human body.
It is required to quickly damp vibrations of relatively large amplitude during traveling. Conventionally, these requirements have been made by improving the seat pad and the seat frame, but it is difficult to satisfy the requirements only on the seat side. Therefore, it is conceivable to use a rubber-like elastic body for the seat suspension that supports and fixes the seat to the floor.
It is difficult to reduce the transmissibility during idling while ensuring damping performance during running.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a seat suspension capable of reducing the transmissibility during idling while ensuring the damping performance during running. .

[0005]

A vehicle seat suspension according to the present invention comprises a seat side mounting member mounted on the seat side, a vehicle body side mounting member mounted on the vehicle body side,
An elastic body provided between both mounting members, a piston-shaped member and a cylinder-shaped member which are coupled via the elastic body and are relatively displaceable in the vibration direction due to elastic deformation of the elastic body when vibration is applied, and magnetic field strength. MR fluid whose viscosity changes depending on the size of the flow path, a flow path formed between the piston-shaped member and the cylinder-shaped member for hermetically holding the MR fluid in a fluid state, and a magnetic field crossing the flow path. It comprises an electromagnet capable of controlling the magnetic field strength for forming a passage and changing the viscosity of the MR fluid.

In the seat suspension of the present invention, when the electromagnet is energized, the viscosity of the MR fluid increases and the piston-shaped member is less likely to be displaced, that is, the rigidity increases, and the internal friction of the MR fluid increases and the damping force also increases. To increase. On the other hand, when the energization to the electromagnet is turned off or the energization current is made smaller, the viscosity of the MR fluid becomes smaller and the piston-like member is easily displaced, that is, the rigidity is lowered.

Therefore, in the seat suspension of the present invention, the energization current to the electromagnet is made larger during running than when idling, more specifically, the energization to the electromagnet is turned off during idling and turned on during running. It is preferable to control so that By controlling in this way, the rigidity of the piston-shaped member is reduced at the time of idling, the transmission rate of microvibration due to idling to the seat is reduced, and the rigidity of the piston-shaped member is increased at the time of running to reduce the damping performance of the elastic body. As well as MR
The damping force due to internal friction of the fluid can also be increased to rapidly damp vibrations of relatively large amplitude.

In the seat suspension of the present invention, the flow passages connect the flow passage portions and the flow passage portions located parallel to each other along the relative displacement direction of the piston-shaped member and the cylinder-shaped member. Is preferably formed in a crank shape in cross section having a flow path portion which is located along a direction orthogonal or substantially orthogonal to the relative displacement direction and which constitutes a transverse portion of the magnetic path.

As described above, the flow path of the MR fluid is formed into a crank shape in cross section, and the magnetic path is crossed to a flow path portion of the crank shape flow path that is substantially orthogonal to the displacement direction of the piston-shaped member. As a result of the increase in the viscosity of the MR fluid in the flow passage corresponding to the crossing point of the magnetic path, the MR
The flow of the fluid can be blocked to rapidly increase the rigidity of the piston-like member. More specifically, for example, by forming the MR fluid flow path in a straight line and crossing the magnetic path in a part of the linear flow path, the rigidity is increased depending on the internal frictional force of the MR fluid whose viscosity increases with energization. It is possible to increase the rate of change of the rigidity (spring constant) with respect to the applied current, as compared with the configuration in which the current is increased. Therefore, the running cost can be reduced by exhibiting the proper and sufficient vibration isolation performance against vibrations during idling and running with less power consumption, and at the same time, the rigidity can be switched between idling and running. Speeding up is achieved.

In the above structure, the electromagnet may be fixedly supported on the cylinder-shaped member side located on the outer periphery of the piston-shaped member, but by fixing and supporting the electromagnet on the piston-shaped member side, the internal space on the piston-shaped member side is fixed. The entire seat suspension can be made compact by making effective use of the electromagnet's installation space.

Further, in the above structure, the cylinder-shaped member is a magnetic path which crosses a flow path portion located along a direction of the MR fluid flow path which is orthogonal or substantially orthogonal to the relative displacement direction with respect to the piston-shaped member. It may be composed of a yoke portion made of a ferromagnetic material and a ring portion made of a non-magnetic or weak magnetic material surrounding and holding the yoke portion. As a result, the leakage of the magnetic flux generated by the electromagnet can be reduced as much as possible, and the magnetic flux can be concentrated in the flow path portion of the MR fluid flow path that corresponds to the magnetic path crossing point, and the power consumption can be further reduced. Further, the rigidity can be switched more quickly.

In the seat suspension of the present invention,
The piston-shaped member and the cylinder-shaped member may be formed integrally with either the seat-side mounting member or the vehicle-body-side mounting member without interposing an elastic body. However, in order to more effectively exhibit the damping performance of the elastic body when the piston-shaped member becomes rigid, the piston-shaped member and the cylinder-shaped member have the elastic body interposed between the seat side mounting member and the vehicle body side mounting member. It is preferable that it is attached.

[0013]

DETAILED DESCRIPTION OF THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a longitudinal sectional view of a seat suspension 10 according to one embodiment of the present invention, and FIG. 2 is a schematic view of a system using this seat suspension 10.

The seat suspension 10 supports the seat 1 of the automobile on a table 2 provided on the floor of the passenger compartment in a vibration-proof manner. One seat suspension is provided at each of the four corners of the lower surface of the seat 1, and a total of four seat suspensions are provided. Has been. In addition, one may be provided at any of the three corners of the four corners, for a total of three.
It is also possible to provide a total of two such that one is provided at each of the front and rear corners, and it is also possible to provide only at any one of the corners.

The seat suspension 10 includes a rubber-like elastic body between a seat-side mounting bracket 12 mounted on a fixed surface portion 3 protruding from the lower surface of the seat 1 and a vehicle-body-side mounting bracket 14 mounted on the floor base 2. Piston-like member 18 and cylinder-like member 20 attached via 16
And are equipped with. That is, in this embodiment, the piston-shaped member 18 and the cylinder-shaped member 20 are attached to the seat-side mounting member 12 with the rubber-like elastic body 16 interposed therebetween, and also to the vehicle-body-side mounting member 14. The elastic body 16 is attached.

Piston-shaped member 18 and cylinder-shaped member 20
Are coupled to each other via the elastic body 16, and when the vibration is applied from the floor side or the seat side, the elastic body 16
It is configured to be relatively displaceable in the vibration direction, that is, in the up-down direction X with the elastic deformation of the. Specifically, the piston-shaped member 1
The reference numeral 8 is a short columnar or disk-shaped having a concave portion 18A extending in the circumferential direction on the outer peripheral surface, and is arranged below the seat side mounting member 12 with its axial direction directed in the vertical direction. The cylinder-shaped member 20 is in the shape of a short cylinder or a ring that surrounds the outer periphery of the piston-shaped member 18 at a predetermined distance. The cylindrical member 20 is made of a ferromagnetic material, and has an annular yoke portion 20A that projects toward the piston-shaped member 18, and a non-magnetic or weakly magnetic material that surrounds and holds the outer peripheral portion of the yoke portion 20A. It is composed of a ring portion 20B.

Piston member 18 and cylinder member 20
A flow path 24 for hermetically holding the MR fluid 22 whose viscosity changes according to the magnetic field strength in a fluid state is formed between the piston-shaped member 18, the cylinder-shaped member 20, and the elastic body 16. It is provided around the outer circumference of 18.

The flow path 24 is a pair of upper and lower vertical flow path portions 24A, 24 positioned parallel to each other along the vertical relative displacement direction X of the piston-shaped member 18 and the cylinder-shaped member 20.
A and an intermediate vertical flow path portion 24B, and a pair of upper and lower vertical flow path portions 24A, 24A and an intermediate vertical flow path portion 24B.
Have a pair of upper and lower horizontal flow path portions 24C, 24C positioned along a direction orthogonal or substantially orthogonal to the vertical relative displacement direction X so as to communicate with each other, and are formed in a crank shape in cross section as a whole. . More specifically, the flow path 24 having a crank-shaped cross section is formed by inserting the inner peripheral end of the yoke portion 20A of the cylinder-shaped member 20 into the recess 18A of the piston-shaped member 18 from the outside thereof.
The vertical flow path portions 24A, 24 are provided on both upper and lower sides of A, respectively.
A is provided, an intermediate vertical flow path portion 24B is provided along the inner peripheral edge of the yoke portion 20A, and horizontal flow path portions 24C, 24C that connect these are provided along the upper and lower surfaces of the yoke portion 20A, respectively. ing.

As shown in FIG. 3, the width d1 of the pair of upper and lower horizontal flow passage portions 24C and 24C is set to be narrower than the width d2 of the pair of upper and lower vertical flow passage portions 24A and 24A. Further, it is preferable that the width d1 is set to be narrower than the width d3 of the intermediate vertical flow path portion 24B.

In the outer peripheral portion of the piston-like member 18, more specifically, in the concave portion 18A, a pair of upper and lower horizontal flow paths of the flow path 24 is provided at a position facing the inner peripheral end of the yoke portion 20A of the cylinder-like member 20. An electromagnet 26 forming a magnetic path mp that crosses the path portions 24C, 24C is annularly arranged and fixedly supported by the piston-shaped member 18. This electromagnet 2
By controlling the current flowing to 6, the flow path 2
The viscosity of the MR fluid 22 can be increased / decreased by controlling the magnetic field strength flowing in the magnetic path mp that crosses the pair of upper and lower horizontal flow passage portions 24C, 24C.

The MR fluid 22 is a Bingham fluid in which ferromagnetic metal fine particles having a particle size of about 1 to 10 μm are dispersed in a high-concentration suspension, and the MR fluid 22 has an operating temperature range of −40 to 150 ° C. The viscosity of the magnetic field changes depending on the strength of the magnetic field, and is called a magnetorheological fluid or a magnetorheological fluid.

As shown in FIG. 2, the seat suspension 10 includes an amplifier 4 for energizing the electromagnet 26.
Further, a control unit 5 for controlling the magnitude of the current flowing through the electromagnet 26 by the amplifier 4 and the ON / OFF of the current supply is connected. The engine speed information is input to the control unit 5, and the energization of the electromagnet 26 is controlled according to this information.

The control method by the control unit 5 is based on the electromagnet 2
The current supplied to 6 is set to be larger when the vehicle is running than when it is idling. Specifically, for example, when the engine speed information is equal to or less than a predetermined value (for example, 1000 times / minute or less), it is determined that the engine is idling, and the electromagnet 26 is determined.
Is turned off, and when the rotation speed information exceeds the above predetermined value, it is determined that the vehicle is traveling and the electromagnet 26 is turned on.
To

In the seat suspension 10, when the energization of the electromagnet 26 is turned on, the viscosity of the MR fluid 22 increases and the piston-shaped member 18 becomes difficult to displace, and the piston-shaped member 18 and the cylinder-shaped member 20 are rigid. Turn into.
Further, as the viscosity of the MR fluid 22 increases, its internal friction increases and the damping force increases. On the other hand, when the power supply to the electromagnet 26 is turned off, the viscosity of the MR fluid 22 is reduced, the piston-shaped member 18 is easily displaced, and the rigidity is reduced.

Therefore, by controlling the energization OFF during idling and the energization ON during running as described above, the rigidity of the piston-shaped member 18 is reduced during idling, and the slight vibration due to idling is elastically deformed by the elastic body 16. The vertical relative displacement between the piston-shaped member 18 and the cylinder-shaped member 20 can be absorbed and the transmission rate of the slight vibration to the seat 1 can be reduced. Further, when the vehicle is running, the rigidity of the piston-shaped member 18 is increased to exhibit the damping performance of the elastic body 16, and the damping force due to the internal friction of the MR fluid 22 is also increased, so that a relatively large amount due to road surface irregularities and the like when the vehicle is running. Vibration of amplitude can be quickly damped.

FIGS. 4 and 5 show the measurement results of the transmissibility and the pulse response displacement with respect to the vertical displacement in the center of body weight of the seat suspension system shown in FIG. For the measurement, a general automobile seat was used as the seat, a 50 kg human body model 6 was used, and a transmissibility was a seat cushion vibration tester (C-1602DL type, Ito Seiki) based on JASO B-407. (Made by KK). For the pulse response displacement, input a pulse equivalent to 5 mm from the vehicle body
It was measured by a seat cushion vibration tester (C-1602DL type, manufactured by Ito Seiki Co., Ltd.) according to SO B-407. Further, as a comparative example, instead of the seat suspension 10, the same was also measured for a seat supported on the floor via a seat suspension made of only metal.

As shown in FIG. 4, in the seat suspension 10 of this embodiment, when the energization is turned off, the transmissibility is significantly reduced especially at 5 to 10 Hz.
Therefore, in a vehicle such as a truck in which the frequency of idling vibration exists near 5 to 10 Hz, the transmission of idling vibration to the seat can be effectively reduced.
In particular, since the resonance frequency of the internal system of the human body is around 6 Hz, the internal system of the occupant can be protected by reducing the transmissibility in the vicinity as shown in FIG.

Further, as shown in FIG. 5, in the seat suspension 10 of this embodiment, the damping force is small when the energization is OFF, but when the energization is ON, the damping force equal to or higher than that of the comparative example is exhibited, and the vibration is reduced. Can be effectively absorbed and reduced.

As described above, the seat suspension 10 of this embodiment can reduce the transmissibility during idling while ensuring the damping performance during running.

In the seat suspension 10 of the present embodiment, the flow passage 24 for the MR fluid 22 has a crank-shaped cross section, and is positioned along a direction substantially orthogonal to the displacement direction of the piston-shaped member 18, and A configuration is adopted in which the magnetic path mp is crossed with respect to the horizontal flow path portion 24C having a small width. For this reason, the viscosity of the MR fluid 22 in the horizontal flow path portion 24C corresponding to the magnetic path crossing portion increases due to the energization, the flow of the MR fluid 22 is blocked, and the rigidity of the piston-shaped member 18 is rapidly increased. Therefore, it is possible to increase the rate of change in rigidity with respect to the applied current.

6 to 9 are enlarged longitudinal sectional views of a main part according to a modification of the seat suspension 10.

In the first modification shown in FIG. 6, an intermediate vertical flow path portion 24B of the flow path 24 formed in a crank shape in cross section.
Is different from the above embodiment in that it is located on the outer side farther from the center of the seat suspension 10 than the pair of upper and lower vertical flow path portions 24A, 24A. Specifically, a concave portion 20C extending in the circumferential direction is provided on the inner peripheral surface of the cylinder-shaped member 20, and the tip of the convex portion 18B provided on the outer peripheral surface of the piston-shaped member 18 is inserted into the concave portion 20C to form a crank-shaped cross section. The channel 24 is formed.

In the second modification shown in FIG. 7, the middle vertical flow passage portion 24B and the lower vertical flow passage portion 24A are arranged in a straight line to form the entire flow passage 24 of the MR fluid 22 in a one-crank shape. This is different from the above embodiment.

The third and fourth modified examples shown in FIGS. 8 and 9 differ from the above-described embodiment in that the electromagnet 26 is arranged and fixed not on the piston-shaped member 18 side but on the cylinder-shaped member 20 side.

More specifically, in the third modification shown in FIG. 8, a concave portion 20D extending in the circumferential direction is formed on the inner peripheral surface of the cylindrical member 20.
Is provided, the electromagnet 26 is arranged and fixed in the recess 20D, and the piston-shaped member 18 is provided in the recess 20D.
A tip end of a convex portion 18C provided on the outer peripheral surface of the is inserted to form a channel 24 having a crank-shaped cross section.

Further, in the fourth modification shown in FIG. 9, a recess 18D extending in the circumferential direction is provided on the outer peripheral surface of the piston-shaped member 18, and an electromagnet provided on the inner peripheral surface of the cylindrical member 20 is provided in the recess 18D. The tip of the convex portion 20E including 26 is inserted to form a flow path 24 having a crank-shaped cross section.

In the third and fourth modified examples, the overall diameter of the seat suspension 10 is slightly larger than that of the above-described embodiment due to the arrangement of the electromagnets 26.

The MR fluid 22 is also used in the first to fourth modified examples.
The channel 24 of the horizontal section has a crank shape in cross section, and the horizontal channel section 24
Since the configuration in which the magnetic path mp is crossed with respect to C is adopted, it is possible to increase the rate of change of rigidity with respect to the energized current, as in the above embodiment.

[0040]

As described above, according to the present invention,
It is possible to provide a high-performance seat suspension that can reduce the transmissibility during idling while ensuring the damping performance during running.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a seat suspension according to an embodiment of the present invention.

FIG. 2 is a schematic view of a system using the seat suspension.

FIG. 3 is an enlarged vertical cross-sectional view of a main part showing a flow path configuration of the seat suspension.

FIG. 4 is a graph showing the relationship between frequency and transmissibility of the seat suspension.

FIG. 5 is a graph showing a pulse response displacement of the seat suspension.

FIG. 6 is an enlarged vertical cross-sectional view of a main part of a seat suspension according to a first modification.

FIG. 7 is an enlarged vertical cross-sectional view of a main part of a seat suspension according to a second modification.

FIG. 8 is an enlarged vertical sectional view of a main part of a seat suspension according to a third modification.

FIG. 9 is an enlarged vertical cross-sectional view of a main part of a seat suspension according to a fourth modification.

[Explanation of symbols]

1 ... sheet 2 ... unit 10: Seat suspension 12: Seat side mounting bracket 14 ... Body side mounting bracket 16 ... Elastic body 18 ... Piston-shaped member 20 ... Cylindrical member 20A ... Yoke part 20B: Ring part 22 ... MR fluid 24 ... Channel 24A, 24B ... Vertical flow path portion 24C: Horizontal flow path 26 ... electromagnet

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F16F 15/023 F16F 13/00 630B F term (reference) 3B087 AA08 DD11 3J047 AA06 AB05 CA16 FA01 3J048 AA06 AD01 BE05 CB21 EA07 3J069 AA38 AA50 AA69 DD25 EE62

Claims (6)

[Claims] 1. A seat side mounting member mounted on a seat side, a vehicle body side mounting member mounted on a vehicle body side, an elastic body provided between both mounting members, and an elasticity when vibration is applied by being coupled through the elastic body. A piston-shaped member and a cylinder-shaped member capable of relative displacement in the vibration direction due to elastic deformation of the body, an MR fluid whose viscosity changes according to the magnitude of the magnetic field strength, formed between the piston-shaped member and the cylinder-shaped member A flow path for hermetically holding the MR fluid in a fluid state, and an electromagnet capable of forming a magnetic path that crosses the flow path and controlling the magnetic field strength for changing the viscosity of the MR fluid. A vehicle seat suspension. 2. A flow path portion located parallel to each other along the relative displacement direction of the piston-shaped member and the cylinder-shaped member and the flow passage portion in the relative displacement direction so as to communicate with each other. 2. The vehicle seat suspension according to claim 1, wherein the vehicle seat suspension is formed in a crank shape in cross section having a flow path portion that forms a transverse portion of a magnetic path and that is located along an orthogonal or substantially orthogonal direction. 3. The vehicle seat suspension according to claim 2, wherein the electromagnet is fixedly supported on the piston member side. 4. A yoke portion made of a ferromagnetic material for forming a magnetic path, wherein the cylindrical member crosses a flow path portion located along a direction orthogonal or substantially orthogonal to the relative displacement direction. The vehicle seat suspension according to claim 2 or 3, comprising a ring portion made of a non-magnetic or weak magnetic material that surrounds and holds the yoke portion. 5. The piston-shaped member and the cylinder-shaped member are mounted on the seat-side mounting member and the vehicle-body-side mounting member with the elastic body interposed therebetween. The vehicle seat suspension described in Crab. 6. The vehicle seat suspension according to claim 1, wherein the electric current supplied to the electromagnet is controlled so as to be larger when the vehicle is running than when the vehicle is idling.