Patent Application
20230101976
The present invention relates to vehicle steering systems with protective bellows and rolling diaphragms.
Steering systems have steering racks ends that extend out of a housing and are connected to tie rods via ball joints. Protective bellows are used to cover and protect these connections. Particularly in harsher environments there is an increased risk of punctures by sticks or rocks that get thrown up. This allows water and contaminants to enter the steering system. Punctured bellows might require the steering system to eventually be replaced if not repaired in time.
One aspect of this disclosure is directed to a steering system comprising a housing, a steering rack which is movably arranged and extends out of a housing end section of the housing on at least one side of the housing with a steering rack end portion, at least one tie rod attached to the steering rack end portion with a ball joint, at least one bellows covering the steering rack end portion, the ball joint and a section of the tie rod adjacent to the ball joint, the bellows haying, a first end and a second end, the first end being attached to the housing end section and the second end being attached to the tie rod at a tie rod attachment section, wherein a rolling diaphragm is arranged inside of the bellows, wherein a first end of the rolling diaphragm is attached to the housing end section and a second end of the rolling diaphragm is attached to at least one of the ball joint and steering rack end portion, and wherein a rolling bend of the rolling diaphragm is movable between the housing and the second end of the bellows. This may provide a second or redundant seal in addition to the bellows. Because of the rolling bend folds or rolls on itself it does not negatively interfere with the bellows. Since the rolling diaphragm is mounted on the ball joint of the steering rack—or inner tie rod—this defines a mid or nominal point in the neutral steering position and allows it to go to full extension travel and minimum travel compression point. Mounting it there also minimizes the impact of the articulation to which the tie rod is subjected. At the fully extended position of the steering rack end there may still be at least a slight roll beyond the second end of the rolling diaphragm.
In some embodiments, the rolling diaphragm has radial and axial dimensions within the bellows so as to not interfere beyond a predetermined range with each other when the steering rack end portion moves between a fully retracted position and a fully extended position and the tie rod pivots on the ball joint during at least one of the group comprising steering movements of the steering rack and up-and-down movements of a suspension.
In some embodiments, the second end of the bellows is located at a distance from the housing which is not smaller than the distance of the rolling bend from the housing when the ball joint is the closest to the housing.
In some embodiments, the housing defines a stop for the ball joint, wherein the steering rack has a position in which the ball joint is the closest to the stop, in which position the rolling bend is the closest to the stop and in which position the tie rod attachment section is at least as far away from the stop as the rolling bend or is further away from the stop than the rolling bend.
In some embodiments, the steering rack has a neutral position away from the position in which the ball joint is the closest to the stop and in in which the tie rod attachment section moves twice as much away from the housing as the rolling bend.
In some embodiments, wherein at least an inner bend of at least a fold of the bellows closest to the second end of the bellows has an inner diameter that is at least as big as an outer diameter of the rolling bend.
In some embodiments, a second end of the rolling diaphragm is attached to the outer circumference of the ball joint.
In some embodiments, a first end of the rolling diaphragm is attached to an inner circumference of the housing end section.
In some embodiments, the rolling bend of the diaphragm is arranged outside of the housing end section.
The above aspects of this disclosure and other aspects will be explained in greater detail below with reference to the attached drawings.
The illustrated embodiments are disclosed with reference to the drawings. However, it is to be understood that the disclosed embodiments are intended to be merely examples that may be embodied in various and alternative forms. The figures are not necessarily to scale and some features may be exaggerated or minimized to show details of particular components. The specific structural and functional details disclosed are not to be interpreted as limiting, but as a representative basis for teaching one skilled in the art how to practice the disclosed concepts.
The sections of the steering rack 14 extending outside of the housing 18, the ball joints 20 and the part of the tie rods 22 adjacent to the ball joints 20 are covered by protective bellows 30. The bellows 30 in automotive applications are also called gaiters or boots. Alternatively, if the ball joints 20 are sufficiently sealed, the bellows 30 may be attached to the ball joints 20 and not on the adjacent part of the tie rods 22. The bellows 30 cover therefore at least the steering rack 14 extending outside of the housing 18 and the ball joints 20 or in addition sections of the tie rods 22. The bellows 30 also define the central axis 28. It shall be noted that the central axis 28 may be angled at the ball joint 20 due to the suspension of a vehicle moving up and down and/or the wheels of a vehicle being turned. The bellows 30 further comprise a first end 32 defining a first opening around the central axis 28 and a second end 34 defining a second opening around the central axis 28. The first ends 32 are connected to the outside of the end sections 26 of the housing 18 for example with a crimp connection or other attachment method. Clamps may be used, too. The second ends 34 are connected to the tie rods 22. The area of the bellows 30 adjacent to the second ends 34 are not shown as a longitudinal sectional view.
A rolling diaphragm 40 or rolling diaphragm seal is arranged inside of the bellows 30. A first end 42 of the rolling diaphragm 40 is attached to the housing end section 26. The first end 42 of the rolling diaphragm 40 may be attached to an inner circumference 44 of the housing end section 26. It may be attached to an outer circumference, too. A second end 46 of the rolling diaphragm 40 may be attached to the ball joint 20. In particular, the second end 46 of the rolling diaphragm 40 may be attached to the outer circumference 48 of the ball joint 20. It is also possible that the second end 46 of the rolling diaphragm 40 is attached to the steering rack 14, in particular the steering rack end portion 36, instead of the ball joint 20, or the steering rack end portions 36, and a disc between the steering rack 14 and an inner side of the ball joint 20. The rolling diaphragm 40 may be directly attached to the steeling rack 14 or indirectly with an intermediate attachment piece such as a washer plate (not shown) between the steering. rack 14 and inner tie rod end. This would allow an easier build during the manufacturing process. It would also allow for the inner tie rod ends to be removed for service without unclamping the diaphragm. The first and second ends 42, 46 may be attached with a clamp and/or by gluing.
A rolling bend 50 of the rolling diaphragm 40 is movable between the housing 18 and the second end 34 of the bellows 30. The part of the rolling diaphragm which constitutes the rolling bend 50 changes depending on the axial extension of the first end 42 and second end 46. The rolling bend 50 defines an arc of approximately 180°. It may be designated as a rolling convolution. The rolling bend 50 of the rolling diaphragm 40 may be arranged outside of the housing end section 26 as depicted in
The rolling diaphragm 40 has radial and axial dimensions within the bellows 30 so that the bellows 30 and the rolling diaphragm 40 do not normally interfere with each other beyond a predetermined range when the steering rack end portion 36 moves between a fully retracted position (
The second end 34 of the bellows 30 may be located at a distance from the housing 18 which is not smaller than the distance of the rolling bend 50 from the housing 18 when the ball joint 20 is the closest to the housing 18 or, as shown in
The housing 18 defines a stop 56 for the ball joint 20. The stop 56 coincides with the axial outside of the bearing 24. The steering rack 14 has a position in which the ball joint 20 is the closest to the stop 56. In this position, the rolling bend 50 is the closest to the stop 56 and in this position the tie rod attachment section 38 is at least as far away from the stop 56 as the rolling bend 50 or, as shown in
The steering rack 14 has a neutral position, as shown in
As mentioned above, the housing 18 has a stop 56 for the ball joint 20 inside of the housing end section 26. The rolling bend 50 has a first rolling bend distance dRB1 to the stop 56 and the tie rod attachment section 38 has a first tie rod attachment section distance dTRA1 to the stop 56 when the steering rack end portion 36 is in a fully retracted position. The rolling bend 50 has a second rolling bend distance dRB2 to the stop and the tie rod attachment section has a second tie rod attachment section distance dTRA2 to the stop 56 when the steering rack end portion 36 is in a neutral position. The rolling bend 50 has a third rolling bend distance dRB3 to the stop and the tie rod attachment section 38 has a third tie rod attachment section distance dTRA3 to the stop 56 when the steering rack end portion 36 is in a fully extended position. The first tie rod attachment distance dTRA1 subtracted by the first rolling bend 50 distance der results in a first difference Δ1. The second tie rod attachment distance dTRA2 subtracted by the second rolling bend 50 distance dRB2 results in a second difference Δ2. The third tie rod attachment distance dTRA3 subtracted by the third rolling bend 50 distance dRB3 results in a third difference Δ3. The third difference Δ3 normally twice as big as the second difference Δ2. The second difference Δ2 is bigger than the absolute value of the first difference Δ1. The above relations may be described with the following formulas: dTRA1−dRB1=Δ1, dTRA2−dRB2=Δ2, dTRA3−dRB3=Δ3, Δ3=>2*Δ2Δ2>|Δ1|. The value of the first difference Δ1 may be less than zero for example in case there is an axial bulge in the flank extending from the second end 34 of the bellows 30 that is axially extending away towards the tip of the tie rod which could accommodate the rolling bend 50.
It is understood that the foregoing detailed description and accompanying examples are merely illustrative and are not to be taken as limitations upon the scope of the invention, which is defined solely by the following claims. Various changes and modifications to the disclosed embodiments will be apparent to those skilled in the art. Such changes and modifications, including without limitation those relating to the chemical structures, substituents, derivatives, intermediates, syntheses, compositions, formulations, or methods of use of the invention, may be made without departing from the spirit and scope thereof.
| Number | Date | Country | |
|---|---|---|---|
| 63250457 | Sep 2021 | US |
