GB2084692A

GB2084692A - Rolling diaphragm gas springs combined with shock absorbers

Info

Publication number: GB2084692A
Application number: GB8126033A
Authority: GB
Original assignee: Atsugi Motor Parts Co Ltd; Nissan Motor Co Ltd
Current assignee: Nissan Motor Co Ltd; Hitachi Astemo Ltd
Priority date: 1980-09-27
Filing date: 1981-08-26
Publication date: 1982-04-15
Also published as: DE3138079A1; FR2491006A1; JPS5760812U

Abstract

A pneumatic spring for vehicle suspensions facilitates removal of a flexible member 26 defining a pneumatic chamber when it is to be replaced or mended. The pneumatic spring is combined with a shock absorber which has a cylinder 10 to which one end of the flexible member is detachably fitted. The shock absorber has a piston connected to a piston rod 16 releasably engaged with an outer shell 14, 20 of the pneumatic spring. The means for permitting the piston rod and outer shell to releasably engage is a threaded bore and a threaded section provided on the piston rod. The connection is sealed. <IMAGE>

Description

SPECIFICATION Structure of a pneumatic suspension for a vehicle The present invention relates generally to a structure of a pneumatic suspension for a vehicle, such as an automotive vehicle. More specifically, the invention relates to an improved structure of releasably assembling the pneumatic suspension.

As is well known, a pneumatic suspension generally comprises a shock absorber having a piston rod extending upwards, and a rolling diaphragm defining a pneumatic chamber between it and the outer periphery of the shock absorber. The shock absorber is connected with a suspension member at the lower end thereof and with the vehicle body at the top of the piston rod for absorbing the bounding and rebounding of the vehicle relative to the suspension member. The pneumatic chamber closed with an outer shell at the top thereof and communicates with a gas source via an induction port and an exhaust port for adjusting the gas pressure therein corresponding to the vehicle level.

Since the rolling diaphragm is made of elastic material for permitting deformation according to variation of the vehicle level, it can be damaged by gravel, pebbles, and so on from the road thrown into the fender of the vehicle body. Conventionally, the outer shell is secured to the piston rod by way of welding, which prevents easy removal of the outer shell from the piston rod to prevent the pneumatic suspension from disassembling easily. In this instance, when the rolling diaphragm is damaged, it is difficult to replace just the rolling diaphragm and sometimes it is necessary to replace the outer shell, the shock absorber, and the rolling diaphragm as a single assembly.

Summary of the Invention Therefore it is an object of the invention to provide a structure of the pneumatic suspension permitting easy replacement and maintenance of the rolling diaphragm and the like.

To accomplish the above-mentioned and other objects, there is provided, according to the present invention, a structure pneumatic suspension in which a piston rod of a shock absorber is engaged with an outer shell with a releasable fastening means.

According to the concept of the invention, there is provided a structure of the pneumatic suspension in use with a vehicle level regulator, for example, which comprises a vehicle body, a shock absorber interpositioned between the vehicle body and a wheel axle, the shock absorber having a reciprocating piston movably disposed therewithin and a piston rod connecting the piston with the vehicle body, a means for releasably connecting the piston rod to the vehicle body, and a flexible member connected to the vehicle body at one end and to the outer periphery of the shock absorber at the other end in order to define a pneumatic chamber.

In the preferred embodiment, the mounting struc turefora pneumatic suspension in a vehicle level regulator comprises a vehicle body formed with a hole including a threaded bore, a shock absorber interpositioned between the vehicle body and a wheel axle for suspending the vehicle on vehicle wheels, the shock absorber including a reciprocating piston and a piston rod for connecting the piston with the vehicle body in order to move the piston in response to the displacement of the vehicle body with respect to said wheel axle, a connecting means for connecting the piston rod with the vehicle body, which includes a threaded means engageable with the threaded bore of the vehicle body, a sealing member having an end interpositioned between the connecting means and the vehicle body for the purpose of leak-proofing, the end of the sealing member being clamped between the connecting member and the vehicle body to establish airtight engagement between the piston rod and the vehicle body, and a flexible member connected to the vehicle body in airtight condition at one end and to the outer periphery of the shock absorber at the other end in airtight condition, the ends being attached to the vehicle body and the shock absorber respectively by a fastening means which releasable fixes the ends onto the vehicle body and the shock absorber with a resilient force.

Brief Description ofthe Drawings The present invention will be more fully understood from the detailed description of the invention given herebelow and from the accompanying drawings of the preferred embodiment of the present invention, which, however, should not be taken as limitative of the invention, but being for elucidation and explanation only.

In the drawings: Figure lisa longitudinal section of the preferred embodiment of a pneumatic suspension according to the present invention; Figure 2 is an enlarged partial section of the structure of Figure 1, in which is illustrated a portion connecting a piston rod to an outer shelf of a vehicle body; and Figure 3 is a view similar to Figure 2 but showing another embodiment of the present invention.

Description of the Preferred Embodiment Referring now to the drawings, particularly to Figure 1, there is illustrated the general construction of a pneumatic suspension interpositioned between a vehicle body and a wheel axle for regulating the vehicle level. The pneumatic suspension mounted onto the vehicle body has a preferred construction of the structure according to the present invention. The pneumatic suspension includes a shock absorber 10 for producing a shock absorbing force against a shock, such as road shock. The shock absorber 10 has a piston (not shown) movably disposed within the shock absorber for motion in response to a shock applied to the vehicle body and/or the wheel axle.

The piston is connected with the vehicle body through a piston rod 16. The shock absorber 10 is, in turn, connected with the wheel axle via a connection ring 18 which is integrally formed with the lower end of the shock absorber.

An outer shell 14 of substantially disc-shaped configuration is attached to the piston rod 16via an interengaging means which will be described in detail herebelow. To the outer shell 14, a cylindrical member 20 is fixedly attached by any suitable manner, such as welding, in gas-proofing condition.

The lower end of the cylindrical member 20 is connected with the upper end 24 of a rolling diaphragm 22 which is made of a flexible material such as flexible resin, rubber and so on. The upper end 24 of the rolling diaphragm 22 is resiliently attached in gas-proofing condition by a fastening ring 25 which is made of resilient material. The rolling diaphragm 22 is turned inwards at the roll portion 26. The end of the turned section 28 is attached with the outer periphery of the shock absorber 10 in gas-proofing condition by a resilient fastening ring 29. The rolling diaphragm 22 and the cylindrical membr 20 define a pneumatic chamber 30 in conjunction with the shock absorber 10. The pneumatic chamber 30 communicates with a gas source via a conduit 31 formed through the piston rod 16.The gas pressure in the pneumatic chamber 30 is controlled by introducing or exhausting the pressurized gas to regulate the vehicle level corresponding to the vehicle level sensed by per se known method and means. One of typical construction of the known vehicle level sensing means is shown in British patent application No.7921228 which, in turn, is published under publication No. 2 028 513 A.

As shown in Figure 2, an attachment 32 with a threaded upper section 34 is attached onto the periphery of the piston by welding or another suitable process. The threaded upper section 34 engages with a threaded lower section 36 of a hole 38 formed in the outer shelf 14. A sealing ring 40 is provided on the piston rod 16 for establish gas-proof between the inner periphery of the pole 38. The attachment 32 has a flange 42 at its lower end. An inwardly-bent end 44 of a cylindrical sealer 46 is secured between the flange 42 and the lower surface of the outer shelf 14.

If the rolling diaphragm 22 is damaged, the threaded upper section 34 can be unscrewed from the threaded lower section 36 to release the outer shell 14 from the piston rod 16. Then, the resilient ring 25 is released from the upper end of the rolling diaphragm to permit the rolling diaphragm 22 disassembled from the cylindrical member 20. Thus, the outer shell 14 and the cylinder member 20 as assembly is loosed from the diaphragm. The rolling diaphragm 20 is placed to the upper end towards down in order to the resilient member 29 being released from the turned section 28. Meanwhile, when the pneumatic suspension is assembled, the section 28 of the diaphragm 20 is attached to the outer periphery of the shock absorber 10 and sealingly fitted thereonto by the resilient ring 29, at first.Then, the rolling diaphragm 20 is turned at the roll portion 26 and is attached the upper end to the outer periphery of the cylindrical member 20. Thereafter, the piston rod 16 passes through the hole 38 of the outer shell 14 for thread engagement of the threaded upper section 34 of the attachment 32 and the threaded lower section 36 of the hole. Thereby, the rolling diaphragm 22 can be removed from the shock absorber 10.

Figure 3 shows the second embodiment of the suspension structure according to the present invention. Since the suspension structure of the second embodiment has generally the same construction as the foregoing first embodiment, the description of the general construction of the structure will be unnecessary. In this embodiment, the outer shell 50 is formed with a hole including a threaded bore 52.

The piston rod 54 is also formed with a threaded portion 56. The threaded bore 52 extends through a projecting portion 58 protruding from the lower surface of the outer shell 50. The projecting portion 58 has a flange 60. An inwardly protruding barb 62 of the cylindrical sealer 64 is engaged with the flange 60 in gas-proof seal. The hole in the outer shell 50 has a tapered section 66 which received a sealing ring 68 providing an gas-proof seal against the piston rod 54.

Similar to the foregoing first embodiment, the outer shell can be easily removed from the piston rod of the shock absorber. This way, the rolling diaphragm can be replaced without replacing the assembled unit.

Claims

1. A structure of a pneumatic suspension for a vehicle comprising: an outer shell; a shock absorber having a reciprocating piston movably disposed therewithin and a piston rod connecting said piston with a vehicle body; a means for releasably connecting said piston rod to said outer shell; and a flexible member connected to said outer shell at one end and to the outer periphery of said shock absorber at the other end in order to define a pneumatic chamber therewithin.

2. A structure of a pneumatic suspension for a vehicle comprising: an outer shell being formed with a hole including a threaded bore; a shock absorber including a piston connected with a vehicle body by a piston rod; connecting means provided on said piston rod, said connecting means having a threaded means which is engageable with said threaded bore for connecting said piston rod to said outer shell; and a flexible member having one end detachably attached to said outer shell and the other end detachably attached to the outer periphery of said shock absorber for defining a pneumatic chamber therewith in.

3. A structure of a pneumatic suspension for a vehicle comprising: an outer shell formed with a hole including a threaded bore; a shock absorber interpositioned between said vehicle body and a wheel axle for suspending the vehicle vehicle wheels, said shock absorber including a reciprocating piston and a piston rod for connecting said piston with said vehicle body in order to move said piston in response to the displacement of the vehicle body with respect to said wheel axle; connecting means for connecting said piston rod to said outer shell, said connecting means including threaded means engageable with said threaded bore of said outer shell;; a sealing member having an end interpositioned between said connecting means and said outer shell for the purpose of leak-proofing, the end of said sealing member being clamped between said connecting member and said outer shell to establish gas-proof engagement between said piston rod and said outer shell; and a flexible member connected to said outer shell in gas-proofing condition at one end and to the outer periphery of said shock absorber at the other end in gas-proofing condition, said ends being attached to said outershell and said shock absorber by fastening means which releasably fixes said ends onto said outer shell and said shock absorber with a resilient force.

4. A structure as set forth in claim 1 or 2, wherein said connecting means comprises an attachment, fixedly attached to the circumference of said piston rod, which includes a threaded section serving as threaded means for interengagement with said threaded bore of said outer shell.

5. A structure as set forth in claim 4, wherein said attachment has a lower flanged section having a flange extending transversely with respect to the piston rod axis, said flange section clamping the upper end of a sealer for airtightness.

7. A structure as set forth in claim 3, wherein said connecting means comprises an attachment fixed to the circumference of said piston rod, which includes threaded means interengageable with said threaded bore for releasably connecting said piston rod to said outer shell, said attachment having a flange portion extending transversely with respect to the piston rod axis, which clamps the end of a sealer between said outer shell to establish an airtight seal therebetween.