JP2000168418A - Vehicle seat - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the vibration shutoff property by generating a large damping force by a damper to a vibration having a large relative displacement between a cushion frame and a pad support member, and generating a small damping force to a vibration having a small relative displacement. SOLUTION: When the airs in lateral air dampers 6 flow in and out in the same phase, a pad support member is vertically moved by a vibration having a large relative displacement between the pad support member and a cushion frame. When the airs in the lateral air dampers 6 synchronously flow in and out in the same phase, the pistons 14 of second air valves 12 are still balanced, so that the second air valves 12 are opened. When the pad support member lowers to press the air dampers 6, first air valves 10 are opened, and the airs in the air dampers 6 flow out through the second air valves 12. When the resistance of the first air valve 10 is set sufficiently small, compared with an orifice 11, the damping force accompanying the outflow of air is minimized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a vehicle seat.

[0002]

2. Description of the Related Art As a conventional vehicle seat, for example, as disclosed in JP-A-5-178139,
There was a structure as shown in FIG. In this prior art, an upper frame to which a seat cushion is attached and a lower frame fixed to the vehicle body side are connected by a substantially X-shaped link mechanism so as to be movable up and down. An air spring for elastically supporting the upper frame and a damper (shock absorber) for attenuating vibration are attached between them.

[0003]

However, in such a conventional vehicle seat, a large space is required due to the large number of components disposed under the seat cushion, and the weight is high due to the complicated structure. Increase, or
Since an air supply source for an air spring is required, it is difficult to apply the air supply source to a general passenger car, and there is a problem in that the vibration isolation of a minute amplitude input is deteriorated due to friction of a mechanical unit and a shock absorber.

[0004] Further, instead of the suspension seat as described above, in order to improve the vibration isolation property, a spring rich seat for a passenger car in which a spring constant is reduced so that a resonance frequency is about 3 Hz by combining a urethane pad and a metal spring. In the case of, the damping force is small structurally and the resonance magnification is large. Therefore, although a good vibration isolation property is obtained for road surface input at a frequency of 4 to 5 Hz or more, the sheet is not subjected to vibration of about 3 Hz. It is difficult to switch the vibration transmission characteristics of the seat according to the road surface input, such as the seat surface moves up and down greatly and the convergence worsens.In addition, the roll and pitch direction stiffness of the seat surface also decrease, and the feeling of swing deteriorates. There was also a problem that it would.

The present invention has been made in view of such conventional problems, and provides a vehicle seat capable of improving overall vibration isolation and suppressing rolling and pitching of a seat surface. The purpose is to:

[0006]

According to the first aspect of the present invention, a cushion frame installed on a floor, a cushion pad in contact with an occupant are provided. A pad supporting member that supports the cushion pad, a link that connects the pad supporting member and the cushion frame so that the pad supporting member can be displaced in a substantially vertical direction, and a link between the cushion frame and the pad supporting member. An elastic body installed on the pad support member to elastically support the pad support member, a damper installed between the cushion frame and the pad support member, and a valve for controlling inflow and outflow of a fluid in the damper,
In a vehicle seat having an orifice that generates a damping force due to inflow and outflow of a fluid, the damper generates a large damping force with respect to a vibration having a large relative displacement between the cushion frame and the pad support member, and It is characterized by comprising damping force switching means for generating a small damping force for a small vibration.

According to a second aspect of the present invention, in the vehicle seat according to the first aspect, a plurality of the dampers are provided, and an imbalance occurs in a load applied to the pad supporting member. In this case, by closing the valve of the damper by the internal pressure difference of the plurality of dampers to prevent the fluid from flowing in and out of the damper, the damper at a portion where a large load is applied and is about to sink is pushed. It is characterized in that the damper at the portion where the force to return is raised has a structure for generating the force to pull back.

According to a third aspect of the present invention, in the vehicle seat according to the first aspect of the invention, the damping force switching means is provided with a small amplitude between the damper itself or between the damper and the valve. An auxiliary fluid chamber made of a flexible material having a capacity capable of absorbing the fluid corresponding to the volume change of the damper due to the vibration of the damper, in series or parallel with the orifice, and the volume change of the damper corresponds to the volume of the auxiliary fluid chamber. In the following cases, the damping force generated by the orifice is reduced.

According to a fourth aspect of the present invention, in the vehicle seat according to the first aspect, when the relative displacement between the cushion frame and the pad support member is large, both of the dampers are provided. It is characterized in that the damping force is small when approaching, and large when leaving.

According to a fifth aspect of the present invention, in the vehicle seat according to the second aspect, the plurality of dampers are arranged side by side in the left-right direction or the front-rear direction of the pad support panel. It is characterized by.

[0011] Further, a sixth invention according to a sixth aspect is characterized in that:
In the vehicle seat according to a second aspect of the present invention, the dampers are disposed at substantially four corners of the pad support panel, and two diagonal lines form a set, and prevent the inflow and outflow of fluid due to the internal pressure difference of each of the dampers. It is characterized by actuating a valve.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a vehicle seat according to the present invention will be described below in detail with reference to the accompanying drawings. (First Embodiment) FIGS. 1 to 6 are views showing a first embodiment of a vehicle seat according to the present invention. 1 is a perspective view, FIG. 2 is (a) a front view and (b) a side view, FIG. 3 is an operation diagram, FIG. 4 is a schematic diagram of an air circuit, and FIG. FIG. 6 is a schematic view showing a difference in the action of the valve depending on the phase of the air damper.

First, the structure will be described. The vehicle seat according to the first embodiment has a structure as shown in FIGS.
Cushion frame 1 installed on the floor and pad support member 3 for supporting cushion pad 2 in contact with an occupant
A link 4 connecting the pad support member 3 and the cushion frame 1; a urethane pad 5 installed between the cushion frame 1 and the pad support member 3; It has an installed air damper 6 and a valve 7 for controlling the flow of air in the air damper 6.

FIG. 4 shows the structure of the air damper 6 and the valve 7. The bottom of the air damper 6 has a plurality of inflow / outflow holes 8 for air, and one of the inflow / outflow holes 8 has a spherical rubber auxiliary air chamber 9 in which, when a negative pressure is applied, it easily buckles and internal air flows out. A first air valve 10 is opened when air flows out of the air damper 6 but is closed when air is flowing in. An orifice 11 is provided in another inflow / outflow hole 8. The first air valve 10 and the outlet of the orifice 11 are connected to each other and connected to the second air valve 12. Further, the second air valve 12 is connected to another inflow / outflow hole 8 of the air damper 6 by a pressure difference detection pipe 13, and the piston 14 moves due to the pressure difference between the left and right air dampers 6, and the ventilation hole 15 opens and closes. It has a structure to do.

Next, the operation of the first embodiment will be described. In the case of one-degree-of-freedom viscous damping vibration, if the resonance frequency is f ₀ , when the damping coefficient is small, the transmissivity near the resonance point increases, but the transmissivity in a high frequency region decreases and the damping coefficient increases. In this case, on the contrary, the transmissivity near the resonance point decreases, but the transmissivity in a high frequency range increases. Therefore, if the input from the vehicle body floor is at the center of the high frequency range where the amplitude is small, the attenuation is reduced, and if the input is at the center of the low frequency range where the amplitude is large, the attenuation is increased to improve the overall vibration isolation. Can be. (See Fig. 5)

First, a case where the air in the left and right air dampers 6 flows in and out in the same phase will be described with reference to FIG. When the relative displacement between the pad support member 3 and the cushion frame 1 is large, the pad support member 3 moves in the vertical direction, and the air in the left and right air dampers 6 flows in and out in phase. Piston 14
Is kept balanced, the second air valve 12 is opened.

When the pad support member 3 is lowered and the air damper 6 is pressed, the first air valve 10 opens, and the air inside the air damper 6 flows out through the second air valve 12.
At this time, the first air valve 10
If the resistance is set to be sufficiently small, the damping force accompanying the outflow of air becomes small.

The pad support member 3 is raised, and the air damper 6
Is expanded and the internal pressure becomes negative, the first air valve 1
0 is closed, the air in the auxiliary air chamber 9 flows into the air damper 6, and the auxiliary air chamber 9 buckles and deforms. When the air in the auxiliary air chamber 9 has completely flowed out, external air flows into the air damper 6 through the orifice 11. At this time, a high damping force is generated, and the vibration on the seat is quickly damped.

When the pad support member 3 is lowered again, first, air flows into the auxiliary air chamber 9 which has been buckled from the air damper 6 to restore its original shape, and then air flows out of the first air valve 10 and thereafter. Repeat this cycle. For this reason, it is possible to quickly attenuate the vibration on the seat seat surface while preventing the vibration greatly pushed up from the floor from being transmitted to the occupant.

Next, the case where the relative displacement between the pad support member 3 and the cushion frame 1 is small and the air in the left and right air dampers 6 flows in and out in the same phase due to small vibration will be described. In this case, the amount of air flowing in and out of the air damper 6 is small. Therefore, when air is filled in the auxiliary air chamber 9,
Although the air flows out from the first air valve 10 when the pad support member 3 is lowered, even when the pad support member 3 is raised, its amplitude is small and the amount of inflow air is small, so that the auxiliary air chamber 9 is buckled and supplied. The amount of air that flows into the air damper 6 can be covered by the amount of air that is supplied.
Similarly, when the pad support member 3 is lowered from this state, most of the air flowing out of the air damper 6 flows into the auxiliary air chamber 9.

Therefore, the amount of air passing through the orifice 11 installed in a circuit parallel to the auxiliary air chamber 9 is small when the pad support member 3 is lowered and when the pad support member 3 is raised, and only a small damping force is generated. Vibration isolation at relatively high frequencies is improved.

As described above, since the damping force of the air damper 6 is switched according to the relative displacement between the pad support member 3 and the cushion frame 1 and the direction of the displacement, the vibration on the seat seat surface is reduced while the thrust due to the large amplitude vibration is reduced. It damps quickly and has excellent vibration isolation properties even for small amplitude vibrations.

Next, referring to FIG. 6B, the case where the entire seat surface including the pad support member 3 is inclined in the roll direction as in the case of cornering, and the air in the left and right air dampers 6 flows in and out of opposite phases. Will be described. Although the pad support member 3 has a structure forming a parallel link with the cushion frame 1, since each part including the pad support member 3 is elastically deformed, a roll on the seat surface occurs.

When an eccentric load acts on the seat surface and the pad support member 3 is tilted, a pressure difference occurs between the internal pressures of the left and right air dampers 6.
For this reason, the balance of the piston 14 of the second air valve 12 connected to the left and right air dampers 6 by the pressure difference detection pipe 13 is lost, and the piston 14 moves to the lower pressure air damper 6 side. As a result, the ventilation hole 15 integrated with the piston 14 is closed, and the inflow and outflow of air in the air damper 6 is blocked. Therefore, the air damper 6 acts as an air spring and suppresses excessive rolling of the pad support member 3. .

When the eccentric load on the seat surface is eliminated, the pressure difference between the left and right air dampers 6 is eliminated, the piston 14 of the second air valve 12 returns to the neutral position by the restoring force of the built-in spring 16, and the ventilation hole 15 is opened. And the air can flow in and out again. The magnitude of the eccentric load for closing the second air valve 12 (the sensitivity of the air valve) can be adjusted by the strength of the spring 16 in the second air valve 12.

In the first embodiment, a urethane pad is used as means for elastically supporting the pad support member 3, but a metal spring such as a coil spring may be used instead. By fixing the torsion bar to the cushion frame 1 and connecting the tip of the arm portion of the torsion bar to the pad support member 3, the link 4 may be omitted and the pad support member 3 may be elastically supported.

Although air is used as the fluid for obtaining the damping force here, if a tank for storing the fluid flowing out of the damper is provided, another fluid including a liquid can be used. Is also possible. The switching of the valves may be performed electrically by an electromagnetic valve or the like.

(Second Embodiment) FIGS. 7 and 8 are views showing a vehicle seat according to a second embodiment of the present invention. FIG. 7 is a sectional view of the air damper 21 with a built-in urethane, and FIG. 8 is a side view.

In the second embodiment, urethane foam 1
9 is covered with a flexible film 17 having no air permeability,
By having a structure in which the film 17 has an air inflow / outflow hole 18, the urethane foam under the pad support member 3, the air damper, and the auxiliary air chamber are integrated. When the integrated urethane built-in air damper 21 bends, the surrounding film 17 sags. However, since the slack acts as an auxiliary air chamber, it is not necessary to provide a separate auxiliary air chamber as in the first embodiment. Absent.

The elastic body incorporated in the damper is not limited to urethane foam, but may be a metal coil spring or the like.

(Third Embodiment) FIG. 9 is a perspective view showing a vehicle seat according to a third embodiment of the present invention. In the third embodiment, two air dampers 6 are arranged in front and back, and when an eccentric load is generated in the front-rear direction due to pitching, the air dampers 6 work to suppress the pitching of the seating surface.

(Fourth Embodiment) FIG. 10 is a perspective view showing a vehicle seat according to a fourth embodiment of the present invention. In the fourth embodiment, four air dampers 6 are arranged at the four corners of the pad support member 3, and two air dampers 6 are arranged diagonally, that is,
The right front and left rear and the left front and right rear air dampers 6 are connected in a pneumatic circuit. Thereby, both rolling and pitching of the seat surface can be suppressed.

[0033]

Since the present invention has the above-described features, a large damping force acts on a vertical movement having a large amplitude, and the vibration quickly converges. Has a small damping force and effectively blocks high-frequency vibrations. In addition, when an eccentric load is applied to the seat surface, the effect of the air damper suppresses the inclination of the seat surface.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a first embodiment of a vehicle seat according to the present invention.

2A is a front view of the first embodiment, and FIG. 2B is a side view of the first embodiment.

FIG. 3 is an operation diagram of the first embodiment.

FIG. 4 is a schematic diagram of a pneumatic circuit according to the first embodiment.

FIG. 5 is a diagram illustrating an example of a change in a vibration transmission curve depending on the magnitude of damping.

FIGS. 6A and 6B are schematic diagrams showing a difference in valve action depending on the phase of the air damper according to the first embodiment, wherein FIG. 6A shows the case of left and right in-phase, and FIG. is there.

FIG. 7 is a cross-sectional view of a urethane-built-in air damper according to a second embodiment.

FIG. 8 is a side view of the second embodiment.

FIG. 9 is a perspective view of a third embodiment.

FIG. 10 is a perspective view of a fourth embodiment.

FIG. 11 is a diagram illustrating a configuration of a suspension seat according to a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cushion frame 2 Cushion pad 3 Pad support member 4 Link 5 Urethane pad 6 Air damper 7 Valve 8, 18 Air inflow / outlet 9 Auxiliary air chamber 10 First air valve 11 Orifice 12 Second air valve 13 Pressure difference detection pipe 14 Piston 15 Vent hole 16 Spring 17 Non-permeable film 19 Urethane foam 20 Metal plate for damper fixing 21 Air damper with built-in urethane

Claims (6)

[Claims] A cushion frame installed on a floor; a cushion pad in contact with an occupant; a pad support member for supporting the cushion pad; a pad support member and the cushion frame; A link connected to be displaceable in the vertical direction, an elastic body installed between the cushion frame and the pad support member, and elastically supporting the pad support member; and a link between the cushion frame and the pad support member. A vehicle seat having a damper disposed therebetween, a valve for controlling inflow and outflow of fluid in the damper, and an orifice for generating a damping force by inflow and outflow of the fluid, wherein the cushion frame and the pad support member The damper generates a large damping force against vibration with a large relative displacement, Vehicle seat, characterized in that it comprises a damping force switching means for generating a small damping force for small vibrations. 2. The vehicle seat according to claim 1, wherein a plurality of the dampers are provided, and when an imbalance occurs in a load applied to the pad supporting member, a difference in internal pressure between the plurality of dampers is provided. By closing the valve of the damper to prevent the fluid from flowing into and out of the damper,
It is characterized in that the damper in a portion where a large load is about to sink and generates a force to push it back, and the damper in a portion where a large load is going to go up has a structure to generate a force to pull it back. Vehicle seat. 3. The vehicle seat according to claim 1, wherein the damping force switching means includes a fluid corresponding to a volume change of the damper caused by vibration of a small amplitude between the damper itself or the damper and the valve. An auxiliary fluid chamber made of a flexible material having a capacity capable of absorbing the pressure is provided in series or in parallel with the orifice, and when the change in the volume of the damper is smaller than the volume of the auxiliary fluid chamber, the attenuation generated by the orifice A vehicle seat characterized in that the force is reduced. 4. The vehicle seat according to claim 1, wherein when the relative displacement between the cushion frame and the pad support member is large, the damper has a small damping force when both approach, and when the damper separates. Is a vehicle seat characterized by being large. 5. The vehicle seat according to claim 2, wherein the plurality of dampers are arranged in a lateral direction or a longitudinal direction of the pad support panel. 6. The vehicle seat according to claim 2, wherein the dampers are arranged at substantially four corners of the pad support panel, and two diagonal lines form a set, and a fluid is generated by an internal pressure difference of each of the dampers. A valve for operating the valve for preventing inflow and outflow of the vehicle.