CA2022028A1 - Composite leaf spring construction having different spring rates for the front and rear portions of the spring - Google Patents
Composite leaf spring construction having different spring rates for the front and rear portions of the springInfo
- Publication number
- CA2022028A1 CA2022028A1 CA 2022028 CA2022028A CA2022028A1 CA 2022028 A1 CA2022028 A1 CA 2022028A1 CA 2022028 CA2022028 CA 2022028 CA 2022028 A CA2022028 A CA 2022028A CA 2022028 A1 CA2022028 A1 CA 2022028A1
- Authority
- CA
- Canada
- Prior art keywords
- spring
- section
- construction
- vehicle
- axle
- 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.)
- Abandoned
Links
Landscapes
- Vehicle Body Suspensions (AREA)
Abstract
COMPOSITE LEAF SPRING CONSTRUCTION
HAVING DIFFERENT SPRING RATE FOR THE
FRONT AND REAR PORTIONS OF THE SPRING
Abstract of the Disclosure A composite leaf spring construction for a vehicle having different spring rates for the front and rear sections of the spring to control rotation of the differential under heavy load conditions. The leaf spring is composed of fiber reinforced resin and has a constant cross sectional area throughout its length.
The front section of the spring has a greater thickness and lesser width than the rear section, thereby provid-ing the front section with a higher spring rate. The vehicle axle is mounted on the front section of the spring forwardly of the transition zone between the sections. The differential spring rate controls rotation of the differential housing and prevents the housing from engaging the floor of a low profile vehicle under heavy load conditions.
HAVING DIFFERENT SPRING RATE FOR THE
FRONT AND REAR PORTIONS OF THE SPRING
Abstract of the Disclosure A composite leaf spring construction for a vehicle having different spring rates for the front and rear sections of the spring to control rotation of the differential under heavy load conditions. The leaf spring is composed of fiber reinforced resin and has a constant cross sectional area throughout its length.
The front section of the spring has a greater thickness and lesser width than the rear section, thereby provid-ing the front section with a higher spring rate. The vehicle axle is mounted on the front section of the spring forwardly of the transition zone between the sections. The differential spring rate controls rotation of the differential housing and prevents the housing from engaging the floor of a low profile vehicle under heavy load conditions.
Description
COMPOSITE LEAF SPRING CONSTRUCTION
HAVING DIFFERENT SPRING RATE FOR THE
FRONT AND REAR PORTIONS OF THE SPRING
~ackground of the Invention Recently there has been a trend to reduce the ;~
profile of vans and trucks to provide a more aero~
dynamic appearance. However, it is important when downsizing the profile of the vehicle that the ground clearance not be reduced and the axle travel be retain~
ed. The "axle travel" is the vertical distance that `
the frame can move downwardly under load before bottom~
ing out on the axle. Under downsized conditions, severe restraints are put on the size and movement of the vehicle suspension and its components.
In a Hotchkiss leaf spring suspension, as the stiffness ratio of the front half of the spring to the rear half of the spring increases, there is a tendency ? ;''"'''``' ""'"' to rotate the differential housing and increase the ~ :
pinion control angle as a load is applied to the sus-pension, the pinion control angle being the degrees of rotation of the pinion axis, per inch of axle travel.
On the other hand, as the stiffness ratio of the front half of the spring to the rear half approaches unity, the pinion control angle is decreased and under heavy load conditions, the differential housing may rotate in a manner to cause the housing to engage and possibly dent the floor of a low profile vehicle. In the past, attempts have been made to overcome this problem b~
mounting protective cross bars beneath the floor in position to be engaged by the differential housing, thus intending to prevent damage to the vehicle floor.
. . .
Summarv of the Invention The invention is directed to a composite leaf spring construction for a vehicle, in which the front and rear sections of the spring have different spring .' ' ~., . ~ .. .. ........ . .. . . . .
HAVING DIFFERENT SPRING RATE FOR THE
FRONT AND REAR PORTIONS OF THE SPRING
~ackground of the Invention Recently there has been a trend to reduce the ;~
profile of vans and trucks to provide a more aero~
dynamic appearance. However, it is important when downsizing the profile of the vehicle that the ground clearance not be reduced and the axle travel be retain~
ed. The "axle travel" is the vertical distance that `
the frame can move downwardly under load before bottom~
ing out on the axle. Under downsized conditions, severe restraints are put on the size and movement of the vehicle suspension and its components.
In a Hotchkiss leaf spring suspension, as the stiffness ratio of the front half of the spring to the rear half of the spring increases, there is a tendency ? ;''"'''``' ""'"' to rotate the differential housing and increase the ~ :
pinion control angle as a load is applied to the sus-pension, the pinion control angle being the degrees of rotation of the pinion axis, per inch of axle travel.
On the other hand, as the stiffness ratio of the front half of the spring to the rear half approaches unity, the pinion control angle is decreased and under heavy load conditions, the differential housing may rotate in a manner to cause the housing to engage and possibly dent the floor of a low profile vehicle. In the past, attempts have been made to overcome this problem b~
mounting protective cross bars beneath the floor in position to be engaged by the differential housing, thus intending to prevent damage to the vehicle floor.
. . .
Summarv of the Invention The invention is directed to a composite leaf spring construction for a vehicle, in which the front and rear sections of the spring have different spring .' ' ~., . ~ .. .. ........ . .. . . . .
2~22~28 :
rates to control rotation of the differential housing and thus prevent the housing from engaging the vehicle floor. `~
In accordance with the invention, the leaf spring is composed of fiber reinforced resin and has a constant cross sectional area throughout its length. ;~
The spring includes a front section having a greater thickness and lesser width than the rear section, thus providing the front section with a substantially higher spring rate. The vehicle axle is preferably mounted to the front section of the spring, forwardly of the transition zone between the front and rear sections. -~
With this construction in which the front section of the composite spring has a substantially ;-greater spring rate than the rear section, rotation of ~ i the differential housing is controlled under heavy load ~-~
conditions to thereby prevent the housing from engaging the floor of the vehicle and possibly damaging the ~ -floor. - ~ -The spring construction of the invention is a ~ ~
compact unit which can be incorporated in vehicles ~ ~-having restrict~d space for the suspension system.
As the construction of the invention incor~
porates a fiber reinforced resin leaf spring, it is ~ -lighter in weight than suspension systems utilizing -steel leaf springs. ` ~ "
The suspension system of the invention can be ~ -used with various types of vehicles and has particular application to light trucks and vans which can encount-er heavy loads during use.
Other objects and advantages will appear in the course of the following description.
Description of the Drawings -The drawings illustrate the best mode ~-presently contemplated of carrying out the invention.
:-.
...... ~, . .. .... . .. ... .... . .
2022~2g In the drawings~
Fig. 1 is a side elevation of the spring construction of the invention: and Fig. 2 is a top plan view of the spring construction.
Description of the Illustrated Embodiment The drawings illustrate a leaf spring con~
struction for a vehicle that has particular application to vehicles that encounter heavy loads during use, such as light trucks or vans. The construction includes a fiber reinforced resin leaf spring 1 that is preferably --composed of substantially continuous fibers bonded by a thermosetting resin, such as an epoxy or polyester resin. The fiber reinforcement may take the form of glass fibers, graphite fibers, or the like.
An eye 2 is connected to the front end of spring 1 and provides an attachment to the vehicle frame, wh-le a standard shackle 3 is connected to the -opposite or rear end of the spring for attachment to the frame. -An axle 4 is mounted on the spring 1 through ~ -~
an axle mount unit 5, which can be similar to that ~-described in copending U.S. Patent Application Serial No. 07/226,460, filed August 1, 1988. The axle mount unit 5 provides a firm connection between axle 4 and spring 1 without the necessity of forming holes in the spring 1 which wouId sever the reinforcement and detract from the mechanical properties of the spring.
In accordance with the invention, spring 1 -~
has a constant cross section area throughout its length and includes a front section 6 and a rear section 7.
Front section 6 has a substantially greater thickness than the rear section, as seen in Fig. 1, and has a substantially lesser width than the rear section, as shown in Fig. 2. Sections 6 and 7 are joined by a : .. : .: ::.. -.
r~
2~22~
rates to control rotation of the differential housing and thus prevent the housing from engaging the vehicle floor. `~
In accordance with the invention, the leaf spring is composed of fiber reinforced resin and has a constant cross sectional area throughout its length. ;~
The spring includes a front section having a greater thickness and lesser width than the rear section, thus providing the front section with a substantially higher spring rate. The vehicle axle is preferably mounted to the front section of the spring, forwardly of the transition zone between the front and rear sections. -~
With this construction in which the front section of the composite spring has a substantially ;-greater spring rate than the rear section, rotation of ~ i the differential housing is controlled under heavy load ~-~
conditions to thereby prevent the housing from engaging the floor of the vehicle and possibly damaging the ~ -floor. - ~ -The spring construction of the invention is a ~ ~
compact unit which can be incorporated in vehicles ~ ~-having restrict~d space for the suspension system.
As the construction of the invention incor~
porates a fiber reinforced resin leaf spring, it is ~ -lighter in weight than suspension systems utilizing -steel leaf springs. ` ~ "
The suspension system of the invention can be ~ -used with various types of vehicles and has particular application to light trucks and vans which can encount-er heavy loads during use.
Other objects and advantages will appear in the course of the following description.
Description of the Drawings -The drawings illustrate the best mode ~-presently contemplated of carrying out the invention.
:-.
...... ~, . .. .... . .. ... .... . .
2022~2g In the drawings~
Fig. 1 is a side elevation of the spring construction of the invention: and Fig. 2 is a top plan view of the spring construction.
Description of the Illustrated Embodiment The drawings illustrate a leaf spring con~
struction for a vehicle that has particular application to vehicles that encounter heavy loads during use, such as light trucks or vans. The construction includes a fiber reinforced resin leaf spring 1 that is preferably --composed of substantially continuous fibers bonded by a thermosetting resin, such as an epoxy or polyester resin. The fiber reinforcement may take the form of glass fibers, graphite fibers, or the like.
An eye 2 is connected to the front end of spring 1 and provides an attachment to the vehicle frame, wh-le a standard shackle 3 is connected to the -opposite or rear end of the spring for attachment to the frame. -An axle 4 is mounted on the spring 1 through ~ -~
an axle mount unit 5, which can be similar to that ~-described in copending U.S. Patent Application Serial No. 07/226,460, filed August 1, 1988. The axle mount unit 5 provides a firm connection between axle 4 and spring 1 without the necessity of forming holes in the spring 1 which wouId sever the reinforcement and detract from the mechanical properties of the spring.
In accordance with the invention, spring 1 -~
has a constant cross section area throughout its length and includes a front section 6 and a rear section 7.
Front section 6 has a substantially greater thickness than the rear section, as seen in Fig. 1, and has a substantially lesser width than the rear section, as shown in Fig. 2. Sections 6 and 7 are joined by a : .. : .: ::.. -.
r~
2~22~
tapered transition zone indicated by 8. As shown in Fig. 1, the upper and lower surfaces of section 6 con-verge and merge into the upper and lower surfaces of rear section 7. As seen in Fig, 2, the side edges of front section 6 diverge and merge into the side edges - ~;
of rear section 7. `
Axle 4 is mounted on the front thicker sec- ;~
tion 6 and is located immediately forward of the :--transition zone 8.
Front section 6 has a substantially higher -spring rate than rear section 7 and the specific ratio -between the spring rates is determined by the particul-ar requirements of the vehicle suspension. In general, the ratio of spring rates between front section 6 and rear section 7 will be in the range of 1:1 to 25:1. As a load is applied to the vehicle, the front section 6 of the spring, having a higher or stiffer spring rate, will be deflected to a lesser degree than the rear `~ -~
section 7, and this will reduce the amount of rotation of the differential housing to prevent the housing from -contacting the floor of the vehicle under maximum load conditions.
As an example, with a stiffness ratio of 8 (the stiffness of front section 6 being eight times `~
that of rear section 7), and a rear to front length ratio of l.S8:1, a pinion control angle of 1.8 per inch of axle travel is obtained. As the stiffness ratio is increased to a value of 25 the pinion control angle will also increase to a value of 2.5 per inch of axle travel, but this increase comes at a diminishing rate. The increased pinion control angle and corres~
ponding downward rotation of the differential housing will act to prevent contact between the differential housing and ~he floor of a low profile vehicle under load conditions. -:-: ~:-:~.
' 2Q22~8 :
of rear section 7. `
Axle 4 is mounted on the front thicker sec- ;~
tion 6 and is located immediately forward of the :--transition zone 8.
Front section 6 has a substantially higher -spring rate than rear section 7 and the specific ratio -between the spring rates is determined by the particul-ar requirements of the vehicle suspension. In general, the ratio of spring rates between front section 6 and rear section 7 will be in the range of 1:1 to 25:1. As a load is applied to the vehicle, the front section 6 of the spring, having a higher or stiffer spring rate, will be deflected to a lesser degree than the rear `~ -~
section 7, and this will reduce the amount of rotation of the differential housing to prevent the housing from -contacting the floor of the vehicle under maximum load conditions.
As an example, with a stiffness ratio of 8 (the stiffness of front section 6 being eight times `~
that of rear section 7), and a rear to front length ratio of l.S8:1, a pinion control angle of 1.8 per inch of axle travel is obtained. As the stiffness ratio is increased to a value of 25 the pinion control angle will also increase to a value of 2.5 per inch of axle travel, but this increase comes at a diminishing rate. The increased pinion control angle and corres~
ponding downward rotation of the differential housing will act to prevent contact between the differential housing and ~he floor of a low profile vehicle under load conditions. -:-: ~:-:~.
' 2Q22~8 :
The suspension system of the invention is a compact construction that can be incorporated with vehicles having a restricted space for the suspension.
The differential spring rate between the front and rear sections of the spring is designed to control rotation of the differential housing and thus prevent the hous-ing from engaging and possibly damaging the floor of `-the vehicle. ~- ;
As the construction of the invention incor-porates a fiber reinforced resin leaf spring it has a ~ `
considerably lesser weight than suspension systems utilizing steel leaf springs.
: ... ...
' '""''''''''~' "'' ''.' ', ' ''.,,.''.'' :, , ~; "
'.',. ." . .~ .~ ~ ,"' ..: -- i:
..~: ~':: ,
The differential spring rate between the front and rear sections of the spring is designed to control rotation of the differential housing and thus prevent the hous-ing from engaging and possibly damaging the floor of `-the vehicle. ~- ;
As the construction of the invention incor-porates a fiber reinforced resin leaf spring it has a ~ `
considerably lesser weight than suspension systems utilizing steel leaf springs.
: ... ...
' '""''''''''~' "'' ''.' ', ' ''.,,.''.'' :, , ~; "
'.',. ." . .~ .~ ~ ,"' ..: -- i:
..~: ~':: ,
Claims (11)
1. A composite leaf spring construction for a vehicle, comprising a leaf spring composed of fiber reinforced resin, connecting means for connecting the ends of said spring to the frame of a vehicle, axle mount means for connecting the spring to an axle of a vehicle, said spring having a constant cross sectional area throughout its length, said spring having a pair of integral sections disposed lengthwise of said spring, a first of said sections having a greater thickness and a lesser width than the second of said sections whereby said first section has a substantially higher spring rate than said second section.
2. The construction of claim 1, wherein said axle mounting means is connected to said first section.
3. The construction of claim 1, and includ-ing a tapered transition zone connecting said first and second sections.
4. The construction of claim 3, wherein said axle mounting means is connected to said first section adjacent said transition zone.
5. The construction of claim 1, wherein said first section is located forwardly in the direction of travel of the vehicle from said second section.
6. A composite leaf spring construction for a vehicle, comprising a leaf spring composed of fiber reinforced resin, connecting means for connecting the ends of the spring to the frame of a vehicle, said spring having a constant cross sectional area throughout its length, said spring having an integral front section and a rear section, said front section having a greater thickness and a lesser width than the rear section, whereby said front section has a substantially higher spring rate than said rear section, and axle mount means for mounting said front section to a vehicle axle.
7. The construction of claim 6, wherein said spring is generally rectangular in cross section and includes an upper surface and a lower surface and a pair of side surfaces, said upper and lower surfaces of said first section converging and merging into the upper and lower surfaces of said second section and the side surfaces of said first section diverging and merg-ing into the side surfaces of said second section.
8. The construction of claim 7, wherein said axle mount means is disposed adjacent the converging upper and lower surfaces.
9. The construction of claim 6, wherein said leaf spring is composed of a single leaf.
10. The construction of claim 5, wherein the fiber reinforcement comprises substantially continuous fibers extending longitudinally of said spring.
11. The construction of claim 6, where the ratio of the spring rate of the front section to the spring rate of the rear section is in the range of 1:1 to 25:1.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US39916289A | 1989-08-25 | 1989-08-25 | |
| US07/399,162 | 1989-08-25 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2022028A1 true CA2022028A1 (en) | 1991-02-26 |
Family
ID=23578409
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2022028 Abandoned CA2022028A1 (en) | 1989-08-25 | 1990-07-26 | Composite leaf spring construction having different spring rates for the front and rear portions of the spring |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2022028A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2634019A1 (en) | 2012-03-01 | 2013-09-04 | Benteler Automobiltechnik GmbH | Motor vehicle axle suspension with longitudinal leaf spring |
-
1990
- 1990-07-26 CA CA 2022028 patent/CA2022028A1/en not_active Abandoned
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2634019A1 (en) | 2012-03-01 | 2013-09-04 | Benteler Automobiltechnik GmbH | Motor vehicle axle suspension with longitudinal leaf spring |
| DE102012101730A1 (en) | 2012-03-01 | 2013-09-05 | Benteler Automobiltechnik Gmbh | Motor vehicle suspension with longitudinal leaf spring |
| US8950766B2 (en) | 2012-03-01 | 2015-02-10 | Benteler-Automobiltechnik GmbH | Axle suspension with longitudinal leaf spring for a motor vehicle |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |