JP2022185824A - air suspension device - Google Patents

Abstract

To provide an air suspension device improved in a degree of freedom in designing spring characteristics of an air spring.SOLUTION: An air piston 32 of an air spring 31 is attached to a piston rod 16 (one side member), and a rolling part 52 of an upper end side (one side) of a diaphragm 51 of the air spring 31 is attached to the air piston 32. By arranging the air piston 32 on a vehicle body side (one side) of a shock absorber 11 having a high degree of freedom in layout, a pressure receiving area of the air piston 32 can be set larger than that of a conventional air suspension device. Therefore, it is possible to enhance a degree of freedom in designing air characteristics of the air spring 31.SELECTED DRAWING: Figure 2

Description

The present invention relates to an air suspension device provided between the vehicle body and wheels of a vehicle and capable of adjusting the vehicle height by supplying and discharging air.

For example, Patent Literature 1 discloses an air suspension device in which a shock absorber and an air spring are arranged coaxially, and the vehicle height is adjusted by supplying and discharging compressed air to an air chamber.

JP-A-8-104118

In the air suspension device described in Patent Document 1 (hereinafter referred to as "conventional air suspension device"), the diaphragm of the air spring rolls on the outer peripheral surface of the air piston attached to the cylinder (outer cylinder) of the shock absorber. do. Therefore, in the conventional air suspension device, the outer diameter of the portion attached to the wheel side of the vehicle is larger than the outer diameter of the air piston by the thickness of the rolling part of the diaphragm in the radial direction. Therefore, due to vehicle layout restrictions, it is difficult to increase the outer diameter of the air piston to secure the pressure receiving area of the air spring, and the degree of freedom in designing the spring characteristics of the air spring is low.

SUMMARY OF THE INVENTION An object of the present invention is to provide an air suspension device in which the degree of freedom in designing the spring characteristics of an air spring is improved.

The air suspension system of the present invention comprises a shock absorber having one side member attached to the vehicle body side and the other side member attached to the vehicle wheel side; An air suspension device comprising: an air spring for adjusting a vehicle height by air supply/discharge, wherein the air spring has an air piston attached to the one side member, and one side of the air spring is rotatably attached to the air piston. and a diaphragm whose other side is attached to the other side member.

According to the present invention, it is possible to improve the degree of freedom in designing the spring characteristics of an air spring in an air suspension device.

It is a front view of the air suspension device according to the present embodiment, and is a view showing an air spring in cross section. It is an explanatory view of the air suspension device according to the present embodiment, and is a cross-sectional view of a part of the shock absorber. It is a figure which expands and shows the principal part (air spring) in FIG.

An embodiment of the present invention will be described with reference to the accompanying drawings. For the sake of convenience, the vertical direction in the drawing will be referred to as the vertical direction.
As shown in FIG. 1 , the air suspension system 1 has a shock absorber 11 and an air spring 31 coaxially provided with respect to the shock absorber 11 .

As shown in FIG. 2, the damper 1 is a double-tube hydraulic damper in which an outer cylinder 13 (cylinder) is provided on the outer circumference of an inner cylinder 12 . An annular reservoir 14 is formed between the inner cylinder 12 and the outer cylinder 12 . A piston 15 is slidably fitted in the inner cylinder 12 . The piston 15 partitions the interior of the inner cylinder 12 into two chambers, an upper chamber 12A and a lower chamber 12B. A lower end side of a piston rod 16 is fixed to the piston 15 . The upper end side of the piston rod 16 is inserted through a rod guide (not shown) attached to the upper end side openings of the inner cylinder 12 and the outer cylinder 13 and extends to the outside of the inner cylinder 12 . An oil seal (not shown) seals between the piston rod 16 and the rod guide.

The piston 15 is provided with an extension-side passage 17 and a contraction-side passage 18 for communicating the upper chamber 12A and the lower chamber 12B. An extension-side damping force generating mechanism 19 that controls the flow of hydraulic fluid flowing through the extension-side passage 17 to generate an extension-side damping force is provided on the lower end side of the piston 15 . On the other hand, on the upper end side of the piston 15, a compression side damping force generating mechanism 20 is provided that controls the flow of hydraulic fluid flowing through the compression side passage 18 to generate a compression side damping force.

A base valve 21 is attached to the lower end side opening of the inner cylinder 12 . Base valve 21 separates lower chamber 12B and reservoir 14 . The base valve 21 is formed with a plurality of notches 22 (only two are shown in FIG. 2) that allow the lower end side of the base valve 21 and the reservoir 14 to communicate with each other. Further, the base valve 21 is provided with an expansion side passage 23 and a contraction side passage 24 that allow the lower chamber 2B and the reservoir 14 to communicate with each other.

A check valve 25 is provided on the upper end side of the base valve 21 to allow the hydraulic fluid to flow from the reservoir 14 side to the lower chamber 12B side in the extension side passage 23 . A compression side damping force generating mechanism 26 is provided on the lower end side of the base valve 21 to control the flow of hydraulic fluid flowing through the compression side passage 24 to generate a compression side damping force. As the working fluid, the upper chamber 12A and the lower chamber 12B are filled with working fluid, and the reservoir 14 is filled with working fluid and gas.

The flow of hydraulic fluid in the buffer 11 will be explained.
During the extension stroke, as the piston 15 moves, hydraulic fluid flows from the upper chamber 12A through the extension-side passage 17 to the lower chamber 12B, thereby generating a damping force by the extension-side damping force generating mechanism. At this time, hydraulic fluid corresponding to the volume of the piston rod 16 withdrawn from the inner cylinder 12 flows from the reservoir 14 through the notch 22 of the base valve 21, the extension side passage 23, and the check valve 25 to the lower chamber 12B. flow to

During the compression stroke, as the piston 15 moves, hydraulic fluid flows from the lower chamber 12B through the compression side passage 18 to the upper chamber 12A, thereby generating a damping force by the compression side damping force generating mechanism 20 . Also, the hydraulic fluid corresponding to the volume of the piston rod 16 entering the inner cylinder 12 flows from the lower chamber 12B through the compression side passage 24 of the base valve 21 to the reservoir 14, thereby generating a compression side damping force generating mechanism. 26 generates a damping force. It should be noted that the gas in the reservoir 14 is compressed by the volume of the working fluid that has flowed.

As shown in FIG. 3, the air spring 31 has a lidded cylindrical air piston 32 with an open lower end (the other side). The air piston 32 is attached to the tip of the piston rod 16 (one side member) of the shock absorber 11 via an insulator 33 . The insulator 33 has a metal washer 34 and a shielding member 35 joined (integrally molded) to the outer periphery of the washer 34 .

The insulator 33 has the shielding member 35 press-fitted into the insulator accommodating portion 36 provided in the lid portion 46 of the air piston 32 . On the other hand, the small diameter portion 27 of the piston rod 16 is inserted through the washer 34 . By tightening the nut 37 screwed onto the screw 28 of the small diameter portion 27 , the inner peripheral portion of the washer 34 moves between the annular surface 29 (stepped portion) of the piston rod 16 and the boss 38 provided on the outer periphery of the small diameter portion 27 . sandwiched between

The shielding member 35 of the insulator 33 is axially pressed by the washer 39 so as to be filled in the insulator accommodating portion 36 . The washer 39 is fixed to a small inner diameter portion 42 formed on the upper end side of the cylindrical portion 41 of the air piston 32 . The washer 39 is positioned in the axial direction (vertical direction) by contacting the lid portion 46 of the air piston 32 (the opening peripheral portion of the insulator housing portion 36) with the outer peripheral edge portion thereof. A bound bumper 40 fitted to the small inner diameter portion 42 of the air piston 32 abuts against the lower surface of the washer 39 (the surface opposite to the insulator 33 side). The piston rod 16 is inserted through the bound bumper 40 .

A rolling portion 52 on the upper end side (one side) of a diaphragm 51 is attached to the cylindrical portion 41 of the air piston 32 . The rolling portion 52 is formed by folding the upper end side of the cylindrical diaphragm 51 inward to form an inverted U-shaped cross section. A peripheral edge portion 53 formed by folding an end portion of the rolling portion 52 inward is fixed to the lower end portion 43 of the cylindrical portion 41 of the air piston 32 by a fixing band 54 . The outer diameter of the lower end portion 43 of the cylindrical portion 41 of the air piston 32 is smaller than the outer diameter of the diaphragm guide surface 44 (diaphragm rolling surface) formed on the outer peripheral surface of the cylindrical portion 41 . The inner diameter of the lower end side (other side) of the cylindrical portion 41 of the air piston 32 is larger than the outer diameter of the cylindrical mounting portion 62 of the spring seat 61, which will be described later.

The air spring 31 has a spring seat 61 (attachment member) attached to the outer cylinder 13 (other side member) of the shock absorber 11 . The spring seat 61 is formed in a lidded cylindrical shape in which a rod insertion hole 64 is formed in a lid portion 63 . The spring seat 61 has an attachment portion 62 to which the upper end portion 30 of the outer cylinder 13 is fitted, and a diaphragm attachment portion 65 to which the lower end portion 55 (other side) of the diaphragm 51 is attached. The lower end portion 55 of the diaphragm 51 is formed by folding the lower end side of the cylindrical diaphragm 51 inward into a U-shaped cross section.

The diaphragm attachment portion 65 has a support portion 66 having an L-shaped cross section and a fixing portion 67 having a cylindrical shape to which the peripheral portion 56 of the diaphragm 51 is fixed. A peripheral edge portion 56 of the diaphragm 51 is formed by folding the end portion of the lower end portion 55 of the diaphragm 51 inward, and is fixed to a fixing portion 67 of the spring seat 61 by a fixing band 57 . The outer diameter of the fixed portion 67 of the spring seat 61 is larger than the outer diameter of the mounting portion 62 and smaller than the outer diameter of the cylindrical portion 68 of the support portion 66 .

Air spring 31 has a cylindrical restraint member 71 that regulates the outer diameter of diaphragm 51 . Between the upper end of the restraining member 71 and the outer peripheral edge of the flange portion 45 of the air piston 32, a dust cover 72 that can extend and contract in the axial direction (vertical direction) is provided. On the other hand, a flexible dust cover 73 is provided between the lower end of the restraining member 71 and the outer peripheral edge of the flange portion 69 of the support portion 66 of the spring seat 61 . The inner diameter of the lower end portion 74 of the restraining member 71 , that is, the portion that restrains the lower end portion 55 of the diaphragm 51 is formed to be about twice the plate thickness of the diaphragm 51 .

The air suspension device 1 is operated by the repulsive force of the compressed air introduced into the air chamber 48 of the air spring 31, that is, the space defined by the air piston 32, the diaphragm 51, the spring seat 61, and the insulator 33. omitted). Further, by controlling the supply and discharge of compressed air to and from the air chamber 48, it is possible to adjust the spring characteristics of the air spring 31, adjust the vehicle height, and control the attitude of the vehicle body.

Here, in a conventional air suspension device, an air piston whose upper end side (one side) is open is provided on the outer circumference of the outer cylinder of the shock absorber, and the rolling part of the diaphragm is attached to the outer circumference of the air piston. Therefore, in the conventional air suspension device, it is difficult to secure the pressure receiving area of the air piston and, in turn, the outer diameter of the air piston due to the restrictions on the layout of the vehicle.

In contrast, in the present embodiment, the air piston 32 of the air spring 31 is attached to the piston rod 16 (one side member), and the air piston 32 is attached to the rolling portion 52 of the air spring 31 on the upper end side (one side) of the diaphragm 51 . attached.
Thus, in this embodiment, by arranging the air piston 32 on the vehicle body side (one side) of the shock absorber 11, which has a high degree of layout freedom, the pressure receiving area of the air piston 32 is made larger than that of the conventional air suspension device. Can be set. As a result, it is possible to increase the freedom in designing the air characteristics of the air spring 31, and by extension, it is possible to improve the ride comfort of the vehicle.
In addition, in this embodiment, even when a heavy load is supported by the air spring 31, the pressure receiving area of the air piston 32 can be set large so that a compressor with higher performance (ability) can be used. It is possible to avoid the increase in manufacturing costs due to using a diaphragm 51 with a higher allowable pressure.
In addition, in the present embodiment, since the rolling portion 52 of the diaphragm 51 is arranged at a higher position on the vehicle body side (a position away from the road surface and the wheels), the rolling portion 52 of the diaphragm 51 and the diaphragm guide surface 44 of the air piston 31 It is possible to suppress dust from entering between As a result, damage to the diaphragm 51 is suppressed, and the durability of the diaphragm 51 can be improved.
Furthermore, in the conventional air suspension device, eccentricity and prying between the shock absorber and the air spring, which are generated when the piston rod strokes, are absorbed by bending the annular connecting portion with the canister. On the other hand, in the present embodiment, the eccentricity and prying between the shock absorber 11 and the air spring 31 that occur when the piston rod 16 strokes is prevented by moving the rolling portion 52 of the diaphragm 51 above the diaphragm guide surface 44 of the air piston 31 . It is possible to absorb it by rolling with , and it is possible to cope with eccentricity and prying to a greater extent.

1 air suspension device, 13 outer cylinder (other side member), 16 piston rod (one side member), 31 air spring, 32 air piston, 48 air chamber, 51 diaphragm

Claims (2)

a shock absorber having one side member attached to the vehicle body side and the other side member attached to the vehicle wheel side; An air suspension device comprising: an air spring that
The air suspension, wherein the air spring has an air piston attached to the one-side member, and a diaphragm whose one side is rotatably attached to the air piston and whose other side is attached to the other-side member. Device. The one-side member is a piston rod, and the other-side member is a cylinder,
2. An air suspension device according to claim 1, wherein the other side of said diaphragm is attached to said other side member via an attachment member provided on one side of said cylinder.

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