CA2267553C - Progressive air spring - Google Patents
Progressive air spring Download PDFInfo
- Publication number
- CA2267553C CA2267553C CA 2267553 CA2267553A CA2267553C CA 2267553 C CA2267553 C CA 2267553C CA 2267553 CA2267553 CA 2267553 CA 2267553 A CA2267553 A CA 2267553A CA 2267553 C CA2267553 C CA 2267553C
- Authority
- CA
- Canada
- Prior art keywords
- chamber
- piston rod
- upper portion
- suspension device
- housing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
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Abstract
An improved suspension device of the air spring type which comprises a hydraulic shock absorber having a body, a piston rod extending outwardly from an end of the body, a flexible diaphragm extending between the body and an upper portion of the piston rod to thereby define a chamber surrounding the piston rod and an upper portion of the body. A liquid is introduced to occupy at least a portion of the chamber and subsequently pressurized air is introduced into an upper portion of the chamber.
The arrangement permits one to reduce the jounce and rebound movement of the suspension device.
The arrangement permits one to reduce the jounce and rebound movement of the suspension device.
Description
PROGRESSIVE AIR SPRING
BACKGROUND OF THE INVENTION
The present invention relates to a suspension device and more particularly, relates to a suspension device useful for vehicles.
Air springs have been used with motor vehicles for a number of years to provide cushioning between the movable parts of the vehicle and primarily to absorb shock loads impressed on the vehicle axles by the wheel striking an object in the road or falling into a depression. These air springs usually consist of a flexible elastomeric sleeve or bellows containing a supply of compressed air having one open end connected to an end plate and a second open end sealingly connected to a piston. The piston is generally mounted on the vehicle axle and includes a portion which extends into the fluid chamber whereby the piston causes compression and expansion within the fluid chamber as the vehicle experiences uneven road conditions and other shocks.
The compressed air within the chamber absorbs the shock. Overall, these air springs function to maintain a predetermined spacing between the vehicle components such as between the tires and wheel wells, as well as maintaining a vehicle body at a predetermined level above the vehicle axle and either maintaining the vehicle body level with respect to the axles or not level in a predetermined and desirable manner.
Basically, air springs function to withstand road shock loads exerted thereon by providing sufficient jounce or collapse movement as well as rebound or expanded movements of the air spring without damaging the flexible sleeve and connected end members. This ensures the proper dampening characteristics so as to protect mechanical components and systems on the motor vehicle from damaging contact with each other and the road.
It is critical that the proper amount of pressurized air be contained within the flexible sleeve so the air spring will perform satisfactorily thereby ensuring the proper dampenings so that undesired contact of the vehicle parts with other parts of the road is eliminated. In short, the proper dampening serves to absorb shock thereby providing a better ride as well as prohibiting or reducing jouncing of the vehicle.
Current air spring designs either incorporate a sealed flexible sleeve with a constant quantity of pressurized air trapped within the chamber or include pressurized air systems for supplying make-up air into the chamber and/or exhaust the extra air from the chamber in order to maintain the desired amount of air in the chamber.
As will be appreciated, the volume of the air within the chamber defined by the bellows will determine the spring rate of the device. There have thus been various proposals to vary the volume of air in the bellows or flexible sleeve to thereby change the spring rate of the device. Such proposals have included supplying or removing air through various control valves and the use of auxiliary air reservoirs which are connected to the bellows or flexible sleeve. Such adjustments can be made when, for example, a vehicle wheel encounters a bump or pothole in the road.
One particular type of air spring suggested in the art comprises a hydraulic shock absorber with an outer air reservoir formed by a flexible sleeve or rolling lobe diaphragm extending between an outer housing of the hydraulic shock absorber and an upper end of the piston rod.
BACKGROUND OF THE INVENTION
The present invention relates to a suspension device and more particularly, relates to a suspension device useful for vehicles.
Air springs have been used with motor vehicles for a number of years to provide cushioning between the movable parts of the vehicle and primarily to absorb shock loads impressed on the vehicle axles by the wheel striking an object in the road or falling into a depression. These air springs usually consist of a flexible elastomeric sleeve or bellows containing a supply of compressed air having one open end connected to an end plate and a second open end sealingly connected to a piston. The piston is generally mounted on the vehicle axle and includes a portion which extends into the fluid chamber whereby the piston causes compression and expansion within the fluid chamber as the vehicle experiences uneven road conditions and other shocks.
The compressed air within the chamber absorbs the shock. Overall, these air springs function to maintain a predetermined spacing between the vehicle components such as between the tires and wheel wells, as well as maintaining a vehicle body at a predetermined level above the vehicle axle and either maintaining the vehicle body level with respect to the axles or not level in a predetermined and desirable manner.
Basically, air springs function to withstand road shock loads exerted thereon by providing sufficient jounce or collapse movement as well as rebound or expanded movements of the air spring without damaging the flexible sleeve and connected end members. This ensures the proper dampening characteristics so as to protect mechanical components and systems on the motor vehicle from damaging contact with each other and the road.
It is critical that the proper amount of pressurized air be contained within the flexible sleeve so the air spring will perform satisfactorily thereby ensuring the proper dampenings so that undesired contact of the vehicle parts with other parts of the road is eliminated. In short, the proper dampening serves to absorb shock thereby providing a better ride as well as prohibiting or reducing jouncing of the vehicle.
Current air spring designs either incorporate a sealed flexible sleeve with a constant quantity of pressurized air trapped within the chamber or include pressurized air systems for supplying make-up air into the chamber and/or exhaust the extra air from the chamber in order to maintain the desired amount of air in the chamber.
As will be appreciated, the volume of the air within the chamber defined by the bellows will determine the spring rate of the device. There have thus been various proposals to vary the volume of air in the bellows or flexible sleeve to thereby change the spring rate of the device. Such proposals have included supplying or removing air through various control valves and the use of auxiliary air reservoirs which are connected to the bellows or flexible sleeve. Such adjustments can be made when, for example, a vehicle wheel encounters a bump or pothole in the road.
One particular type of air spring suggested in the art comprises a hydraulic shock absorber with an outer air reservoir formed by a flexible sleeve or rolling lobe diaphragm extending between an outer housing of the hydraulic shock absorber and an upper end of the piston rod.
-2-While such proposals have been advanced in the art, there does not exist a combination shock absorber air spring which is inexpensive to manufacture and is suitable for reducing the rebound action of such devices. Typically, when such suspension devices are used in environments where extreme conditions are encountered, such as in off road vehicles and other vehicles such as snowmobiles, the standard shock absorber does not provide su~cient control. In some circumstances this can be dangerous as a driver can be thrown into a position where control might be lost. Thus, depending on load factors and terrain to be encountered, the volume of air within the chamber must be increased substantially. This will also increase the forces acting on the vehicle when bumps are encountered.
SUMMARY OF THE INVENTION
It is accordingly an object of the present invention to provide a suspension device which is economical to manufacture and imparts desirable ride characteristics to the vehicle.
According to one aspect of the present invention, there is provided a suspension device comprising a hydraulic shock absorber having an outer housing, a piston within said housing, a piston rod extending through an end of the housing, a rolling lobe diaphragm connected to an exterior of the housing and to the piston rod to define a chamber, a liquid within the chamber, the liquid occupying at least 20% of the volume of the chamber when said piston rod is in a generally retracted position, and an air inlet to the chamber located proximate the point where the diaphragm is connected to the piston rod.
SUMMARY OF THE INVENTION
It is accordingly an object of the present invention to provide a suspension device which is economical to manufacture and imparts desirable ride characteristics to the vehicle.
According to one aspect of the present invention, there is provided a suspension device comprising a hydraulic shock absorber having an outer housing, a piston within said housing, a piston rod extending through an end of the housing, a rolling lobe diaphragm connected to an exterior of the housing and to the piston rod to define a chamber, a liquid within the chamber, the liquid occupying at least 20% of the volume of the chamber when said piston rod is in a generally retracted position, and an air inlet to the chamber located proximate the point where the diaphragm is connected to the piston rod.
-3-A method of improving the ride characteristics of a suspension device comprising a hydraulic shock absorber having a body, a piston rod extending outwardly from the body and a flexible diaphragm extending between the body and an upper portion of the piston rod to thereby define a chamber surrounding the piston rod and an upper portion of the body, the method comprising the step of introducing a liquid into the chamber and subsequently introducing a pressurized gaseous material into an upper portion of the chamber.
In greater detail, the suspension device of the present invention is designed to be used with conventional hydraulic shock absorbers such as found on many vehicles, both automotive and otherwise. The design and structure of such shock absorbers is well known in the art and need not be discussed herein. However, it will be noted that the present invention may be used with a single acting shock absorber compared to the normal double acting shock absorber thereby lowering the cost of manufacture of the present suspension device.
The hydraulic shock absorber includes a piston within the housing and a piston rod extending from one end of the housing. Conventionally, a distal end of the piston rod and an opposed end of the housing will carry means for mounting the suspension device on the vehicle. Such mounts include the well known and conventional ring mount.
The present invention provides a rolling lobe flexible diaphragm which is connected to an exterior of the housing and also to the piston rod to thereby define a chamber. Again, the means of connection and the various types of diaphragm
In greater detail, the suspension device of the present invention is designed to be used with conventional hydraulic shock absorbers such as found on many vehicles, both automotive and otherwise. The design and structure of such shock absorbers is well known in the art and need not be discussed herein. However, it will be noted that the present invention may be used with a single acting shock absorber compared to the normal double acting shock absorber thereby lowering the cost of manufacture of the present suspension device.
The hydraulic shock absorber includes a piston within the housing and a piston rod extending from one end of the housing. Conventionally, a distal end of the piston rod and an opposed end of the housing will carry means for mounting the suspension device on the vehicle. Such mounts include the well known and conventional ring mount.
The present invention provides a rolling lobe flexible diaphragm which is connected to an exterior of the housing and also to the piston rod to thereby define a chamber. Again, the means of connection and the various types of diaphragm
-4-materials are well known in the art and need not be discussed herein.
According to the present invention, there is provided a liquid within the chamber and means for introducing air into the chamber.
The amount of liquid introduced into the chamber may vary and preferably comprises at least 20% of the chamber volume when the piston rod is in a substantially retracted position. Subsequently, pressurized air may be added through the pressurized air inlet to provide for the desired ride characteristics.
Even more preferably, the liquid will comprise at least SO% of the chamber volume.
The liquid employed may be selected from any suitable liquid consistent with normal required properties such as the liquid not being subject to freezing at normal ambient temperatures, non corrosive, etc. Thus, any number of suitable oils which are compatible with the diaphragm and hydraulic shock absorber may be utilized.
BRIEF DESCRIPTION OF THE DRAWINGS
Having thus generally described the invention, reference will be made to the accompanying drawings illustrating an embodiment thereof, in which:
Figure 1 is a side elevational view, partially in cutaway, of a combination air spring/hydraulic shock absorber with the piston rod extended; and Figure 2 is a view similar to Figure 1 illustrating the suspension device with the piston rod in a retracted position.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to the drawings in greater detail and by reference characters thereto, the suspension device of the present invention is generally designated by reference
According to the present invention, there is provided a liquid within the chamber and means for introducing air into the chamber.
The amount of liquid introduced into the chamber may vary and preferably comprises at least 20% of the chamber volume when the piston rod is in a substantially retracted position. Subsequently, pressurized air may be added through the pressurized air inlet to provide for the desired ride characteristics.
Even more preferably, the liquid will comprise at least SO% of the chamber volume.
The liquid employed may be selected from any suitable liquid consistent with normal required properties such as the liquid not being subject to freezing at normal ambient temperatures, non corrosive, etc. Thus, any number of suitable oils which are compatible with the diaphragm and hydraulic shock absorber may be utilized.
BRIEF DESCRIPTION OF THE DRAWINGS
Having thus generally described the invention, reference will be made to the accompanying drawings illustrating an embodiment thereof, in which:
Figure 1 is a side elevational view, partially in cutaway, of a combination air spring/hydraulic shock absorber with the piston rod extended; and Figure 2 is a view similar to Figure 1 illustrating the suspension device with the piston rod in a retracted position.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to the drawings in greater detail and by reference characters thereto, the suspension device of the present invention is generally designated by reference
-5-numeral 10 and includes a hydraulic cylinder which is also generally designated by reference numeral 12.
Hydraulic cylinder 12 includes a cylinder housing 14; at a first end 16 thereof, there is provided a conventional ring mount 18.
A piston rod 20 extends through end 22 of housing 14 and also includes a conventional ring mount 24.
An outer housing extends between an upper portion of piston rod 20 and cylinder housing 14 to therebetween define a chamber 34. The outer housing is comprised of an upper rigid portion having a cylindrical body 25 and a top cap connected to body 25 at a marginal edge 30 thereof. A flexible diaphragm 26 extends between a lower edge of cylindrical body 25 and an upper portion of cylinder housing 14.
An air inlet 32 is provided within cover 28 in order to pressurize chamber 34.
As shown in Figures 1 and 2, a liquid 36 is provided within chamber 34, with the liquid occupying most of the space when the piston rod 20 is in the retracted position shown in Figure 2. In the extended position, as shown in Figure l, a substantially greater volume of air is provided within chamber 34.
Thus, once the liquid is introduced into the chamber with the piston rod 20 being in the retracted position, the remaining volume may be pressurized with air by means of air inlet 32. The amount of pressurization will vary depending upon load factors, terrain, etc. The amount of pressurized air will naturally determine the vehicle body level with respect to the axles.
Hydraulic cylinder 12 includes a cylinder housing 14; at a first end 16 thereof, there is provided a conventional ring mount 18.
A piston rod 20 extends through end 22 of housing 14 and also includes a conventional ring mount 24.
An outer housing extends between an upper portion of piston rod 20 and cylinder housing 14 to therebetween define a chamber 34. The outer housing is comprised of an upper rigid portion having a cylindrical body 25 and a top cap connected to body 25 at a marginal edge 30 thereof. A flexible diaphragm 26 extends between a lower edge of cylindrical body 25 and an upper portion of cylinder housing 14.
An air inlet 32 is provided within cover 28 in order to pressurize chamber 34.
As shown in Figures 1 and 2, a liquid 36 is provided within chamber 34, with the liquid occupying most of the space when the piston rod 20 is in the retracted position shown in Figure 2. In the extended position, as shown in Figure l, a substantially greater volume of air is provided within chamber 34.
Thus, once the liquid is introduced into the chamber with the piston rod 20 being in the retracted position, the remaining volume may be pressurized with air by means of air inlet 32. The amount of pressurization will vary depending upon load factors, terrain, etc. The amount of pressurized air will naturally determine the vehicle body level with respect to the axles.
-6-Upon encountering unevenness in the terrain, the extent of movement and the force for both the jounce and rebound movement will be minimized due to the progressive action of the arrangement - i.e. less movement is encountered for a given force acting thereon.
It will be understood that the above described embodiment is for purposes of illustration only and that changes and modifications may be made thereto without departing from the spirit and scope of the invention. For example, the use of the liquid could be incorporated in a normal air spring.
It will be understood that the above described embodiment is for purposes of illustration only and that changes and modifications may be made thereto without departing from the spirit and scope of the invention. For example, the use of the liquid could be incorporated in a normal air spring.
Claims (14)
1. A suspension device comprising a hydraulic shock absorber having a body, a piston rod extending outwardly from said body, a housing extending between said body and an upper portion of said piston rod to thereby define a chamber surrounding said piston rod and an upper portion of said body, at least a portion of said housing being formed of a flexible diaphragm, a liquid occupying at least a portion of said chamber, and means for introducing a pressurized gaseous material into an upper portion of said chamber.
2. The suspension device of Claim 1 wherein said housing comprises an upper rigid portion connected to said piston rod, said flexible diaphragm being secured to said upper rigid portion and to said body.
3. The suspension device of Claim 2 wherein said flexible diaphragm is secured proximate one end of said body, said one end being located proximate to where said piston rod extends outwardly therefrom.
4. The suspension device of Claim 2 wherein said liquid occupies at least 20%
of a volume of said chamber.
of a volume of said chamber.
5. The suspension device of Claim 1 wherein said liquid occupies at least 50%
of a volume of said chamber.
of a volume of said chamber.
6. The suspension device of Claim 2 wherein said shock absorber comprises a single acting shock absorber.
7. A method for improving the ride characteristics of a suspension device which comprises a hydraulic shock absorber having a body, a piston rod extending outwardly from said body, a housing extending between said body and an upper portion of said piston rod to thereby define a chamber surrounding said piston rod and an upper portion of said body with a lower portion of said housing connected to said body being a flexible diaphragm, said method comprising introducing a liquid into said chamber, and subsequently introducing a pressurized gaseous material into an upper portion of said chamber.
8. The method of Claim 7 wherein the step of introducing a liquid into said chamber comprises a step of introducing said liquid into said chamber when said piston rod is in a retracted position and introducing sufficient liquid to occupy at least 50% of a volume of said chamber.
9. In a multi wheeled vehicle having a suspension system associated with each wheel, the improvement wherein at least one of said suspension systems consist essentially of a suspension device comprising a hydraulic shock absorber having a body, a piston ring extending outwardly from said body, a housing extending between said body and an upper portion of said piston rod to thereby define a chamber surrounding said piston rod and an upper portion of said body, at least a portion of said housing being formed of a flexible diaphragm, a liquid occupying a portion of said chamber, and means for introducing a pressurized gaseous material into an upper portion of said chamber.
10. The improvement of Claim 9 wherein each of said wheels has a suspension system as defined in Claim 9.
11. The improvement of Claim 9 wherein said vehicle is an all terrain vehicle.
12. The improvement of Claim 9 wherein said housing comprises an upper rigid portion connected to said piston rod, said flexible diaphragm being secured to said upper rigid portion and to said body.
13. The improvement of Claim 12 wherein said flexible diaphragm is secured proximate one end of said body, said one end being located proximate to where said piston rod extends outwardly therefrom.
14. In a snowmobile having a suspension system associated with each ski, the improvement wherein each of said suspension systems consist essentially of a suspension device comprising a hydraulic shock absorber having a body, a piston rod extending outwardly from said body, a housing extending between said body and an upper portion of said piston rod to thereby define a chamber surrounding said piston rod and an upper portion of said body, at least a portion of said housing being formed of a flexible diaphragm, a liquid occupying a portion of said chamber and means for introducing a pressurized gaseous material into an upper portion of said chamber.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US5513598A | 1998-04-03 | 1998-04-03 | |
| US09/055,135 | 1998-04-03 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2267553C true CA2267553C (en) | 2000-12-05 |
Family
ID=29709189
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2267553 Expired - Fee Related CA2267553C (en) | 1998-04-03 | 1999-03-30 | Progressive air spring |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2267553C (en) |
-
1999
- 1999-03-30 CA CA 2267553 patent/CA2267553C/en not_active Expired - Fee Related
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |