Arrangement for a steering system of a vehicle

Abstract

Arrangement (10) for a steering system of a vehicle, the arrangement comprising: an axle part (14) with a coupling recess (28), and a steering cylinder (12) with a coupling projection (22); wherein the coupling projection (22) is received in the coupling recess (28) and a press fit is formed therebetween.

Description

[0001] The present disclosure relates to an arrangement for a hydraulic steering system of a vehicle, in particular a hydraulic steering system. The vehicle may, in particular, be a road vehicle, such as a car or a bus. The steering system may, for example, be configured to steer wheels of the vehicle that are attached to a common axle of the vehicle, e.g., a front or rear axle.

[0002] Steering systems that include a steering cylinder for steering the wheels of a vehicle are known. The steering cylinders are typically fluidly driven, e.g., pneumatically or hydraulically, and convert hydraulic pressure or pneumatic force into linear movement. This linear movement is transmitted, e.g., to a steering linkage or a rack and pinion mechanism connected to one or more wheels of the vehicle. Steering cylinders may comprise a main part, e.g., a cylindrical tube or sleeve, and at least one movable part, e.g., a rod, connected, e.g., to a steering linkage, a steering knuckle, or a rack and pinion mechanism. The cylinder tube and piston may jointly enclose a fluid chamber whose volume is adjustable depending on the generated fluid pressure.

[0003] The aspects of known steering cylinders described above may also apply to a steering cylinder described herein.

[0004] In order to safely transmit the generated linear movement, or in other words, the steering forces that cause this linear movement, the steering cylinders are usually attached to adjacent parts of the vehicle. Existing solutions for achieving this fixation have been found to be disadvantageous. For example, they may require extensive design modifications to the steering cylinder and / or the surrounding part. The resulting designs may be limited to a specific pairing between a steering cylinder and a surrounding part. For example, the surrounding part often has to be specially adapted for each variant of the steering cylinder in order to be attached to it. In addition, existing solutions may require a large number of additional parts, such as screws, and / or increased time for assembling the entire steering system.

[0005] It is therefore an object of the present disclosure to mitigate at least some of the existing disadvantages.

[0006] Accordingly, the present disclosure proposes an arrangement for a steering system of a vehicle, the arrangement comprising: • an axle part with a coupling recess and • a steering cylinder having a coupling projection;wherein the coupling projection is received in the coupling recess and an interference fit is formed therebetween, ie between the coupling projection and the coupling recess.

[0007] The steering cylinder can be fluidically driven, in particular hydraulically or pneumatically driven. It can be an elongated element whose longitudinal axis coincides with or runs parallel to a first axis disclosed herein, along which steering forces can be generated. The steering cylinder can have a round, in particular circular, cross-section, at least in sections. The steering cylinder, in particular a main part or a main housing, can have opposite ends, e.g., viewed along its longitudinal axis. At least part of a movable piston or rod of the steering cylinder can be arranged at each end. In a generally known element, further parts, such as mechanical connections, can be connected to the piston or rod in order to transmit the steering forces to the steerable wheels of the vehicle.In one example, the steering cylinder may be configured to move the piston or rod at each end thereof linearly along the longitudinal axis and / or the first axis mentioned below.

[0008] In general, the steering cylinder can be configured to steer two wheels of the vehicle. It can be arranged between the wheels and, in particular, at a substantially equal distance from each of the wheels.

[0009] The coupling projection may, for example, protrude from and / or protrude relative to a housing, a main part, or an outer peripheral surface of the steering cylinder. It may, for example, protrude from the housing, the main part, or the outer peripheral surface toward the axle part and thus away from a longitudinal axis and / or the first axis described below.

[0010] The axle component may be stationary. As described further below, it may comprise a housing that accommodates and / or is connected to other axle components. For example, at least part of a transmission set, and in particular a differential of a driven axle of the vehicle, may be housed in the axle component.

[0011] The press fit can be designed to reliably fasten the steering cylinder to the axle part, for example, even under expected operating forces, in particular steering forces. For example, the sizes of the contacting surfaces of the coupling projection and the coupling recess and / or the tolerances between the contacting surfaces can be adjusted accordingly. As a result, the press fit can generate sufficiently large clamping forces. In other words, the press fit can define a fixed bearing or counterbearing of the steering cylinder on (or at) the axle part, so that the steering cylinder is supported on the housing when the steering forces are generated and / or rests immovably against the housing. In particular, the steering cylinder can be held immovably on the axle part by the press fit and held immovably relative to it.

[0012] The interference fit may include a positive connection between the coupling recess and the coupling projection. Accordingly, the coupling recess and the coupling projection may be complementarily shaped, at least in sections.

[0013] In one embodiment, the arrangement further comprises at least one screw connection that connects the coupling projection and the coupling recess to one another and, in particular, presses them against one another. The screw connection can generate at least part of the clamping forces necessary to reliably fasten the steering cylinder to the axle part. In such a case, the interference fit can be configured to connect the coupling projection and coupling recess less tightly than in designs in which no corresponding screw connection is present. Additionally or alternatively, the screw connection can serve as a redundant securing of the coupling projection and the coupling recess to one another.

[0014] In general, the steering cylinder may be configured to generate steering forces along a first axis, which may in particular be a longitudinal axis of the steering cylinder.

[0015] In one embodiment, the interference fit is configured to prevent relative movement between the coupling recess and the coupling projection along the first axis. In other words, the coupling recess and the coupling projection can be prevented from moving relative to each other. Additionally or alternatively, the interference fit can prevent movement along an axis orthogonal to the steering axis. This can prevent the coupling projection and the coupling recess from being pulled away from each other and / or lifted off each other. In general, the interference fit can be configured to suppress any relative movement between the coupling recess and the coupling projection.

[0016] In another embodiment, the interference fit is configured, for example, to prevent relative rotation about a second axis, wherein the second axis may lie in a plane extending orthogonally to the first axis.

[0017] According to a further embodiment, the steering cylinder comprises a master cylinder part to which the coupling projection is welded or otherwise connected. The master cylinder part can, for example, comprise or surround a fluid chamber in which a pressurized fluid can be accommodated to generate steering forces. The master cylinder part can have at least partially a round or circular cross-section. It can be a cylinder tube or comprise a cylinder tube. It can be a one-piece element or a multi-piece arrangement. The master cylinder part can contact the axle part at least in sections. The axle part can have a contact surface that is correspondingly shaped and, in particular, correspondingly rounded compared to a section of the surface of the master cylinder part that contacts this contact surface.

[0018] In general, the axle member cannot enclose or surround the steering cylinder and / or the master cylinder member, e.g., by circumferentially enclosing or circumferentially surrounding at least a portion thereof. Accordingly, the steering cylinder and / or the master cylinder member cannot be inserted into and / or passed through openings or through-holes of the axle member.

[0019] The coupling projection may be configured to protrude from and / or relative to an outer peripheral surface of the steering cylinder.

[0020] The at least one optional screw connection can comprise a screw, a threaded bore for receiving a threaded shank of the screw, and a bearing surface for a screw head of the screw. The threaded bore can be formed in only one of the axle body and the steering cylinder, and in particular only in one of the coupling recess and the coupling projection. Alternatively, both the axle part and the steering cylinder, and in particular the coupling recess and the coupling projection, can each have a section of the threaded bore. For example, the coupling recess can comprise a first section of the threaded bore, while the coupling projection can comprise a second section of the threaded bore, wherein the first section and the second section can be aligned with one another to form a continuous and / or elongated threaded bore configured to receive the screw.

[0021] Accordingly, at least part of the threaded bore can be encompassed by the axle part and, in particular, by its coupling recess. Additionally or alternatively, the support surface can be encompassed by the steering cylinder and, in particular, by its coupling projection.

[0022] According to a further embodiment, the steering cylinder is configured to generate steering forces along a first axis, and the at least one screw extends at an angle to this first axis. For example, the screw may extend perpendicular to the first axis and / or such that it is not aligned along an axis of the steering forces. Alternatively, a contact surface between the coupling recess and the coupling projection, which are pressed against each other, e.g., by the screw connection, may run parallel to the first axis.

[0023] According to another example, the axle part is a housing part of an axle component. For example, the housing part can be designed to accommodate at least part of a differential or another axle component.

[0024] In one embodiment, the coupling recess is formed as a locally recessed area on an outwardly facing surface of the axle part. The outwardly facing surface can be accessible from the outside so that, for example, the coupling projection can be engaged with it to form the interference fit.

[0025] The locally recessed region may have a bottom surface that is recessed, for example, relative to the surrounding outer surfaces of the axle part. The locally recessed region may have side surfaces that connect the bottom surface to the surrounding outer surfaces. In general, the locally recessed region may have at least one open side surface. In particular, the open side surface may be arranged and / or oriented such that the coupling projection can be inserted into the coupling recess through or along the open side surface and / or can protrude from the coupling recess through the open side surface.

[0026] In one example, the coupling projection is configured to protrude from and / or relative to an outer peripheral surface of the steering cylinder, and in particular a main part of the steering cylinder.

[0027] In another example, at least two screw connections are provided to press the coupling recess and coupling projection against each other and, in particular, to connect them directly. In the latter case, both screw connections can extend through the coupling projection and the coupling recess and / or be at least partially accommodated therein.

[0028] The present disclosure also relates to an axle member and a steering cylinder for configuring an arrangement according to any of the examples disclosed herein. For example, the axle member may include a coupling recess having any of the features described herein. Similarly, the steering cylinder may include a coupling projection having any of the features described herein.

[0029] Exemplary embodiments according to the present disclosure are discussed below with reference to the schematic figures. Fig. 1 shows a perspective view of an arrangement according to a first embodiment. Fig. 2 shows a sectional view of the arrangement according to the first embodiment.

[0030] Fig. 1 shows a perspective view of an assembly 10 for configuring a driven and steerable vehicle axle. The assembly 10 is configured according to an exemplary first embodiment. The assembly 10 includes a steering cylinder 12 and an axle part 14. The axle part 14 is a housing, often referred to as a center housing. The axle part 14 includes an interior space 16 for accommodating at least part of a differential. The axle part 14 is connected to other axle components not shown.

[0031] The steering cylinder 12 comprises a main part 18, which may also be referred to as a main housing. The main part 18 encloses a fluid chamber (not shown) for receiving a pressurized fluid, e.g., hydraulic oil. The main part 18 extends along a longitudinal axis L, which coincides with a first axis A within the meaning of this disclosure. The main part 18 has a substantially circular cross-sectional shape, e.g., when viewed in a cross-sectional plane extending orthogonal to the axes L, A. In other words, the main part 18 has a substantially circular circumference, e.g., extending around the axes L, A. Furthermore, the main part 18 is generally cylindrical and / or tubular.

[0032] At the opposite axially outer ends of the main part 18, parts of the pistons 20 extend axially outward. These pistons 20 are axially movable depending on a pressure generated in the fluid chamber (not shown) inside the main part 18. The pistons 20 are each coupled to further components of a steering linkage and in particular to a steerable wheel of the vehicle. In a generally known manner, the axial movement of the pistons 20 can be converted into a steering movement of the vehicle wheels, wherein the vehicle wheels are encompassed by and / or form a common axle of the vehicle. The movement of the pistons 20 is generated by a steering force that runs along the first axis A.

[0033] A coupling projection 22 extends from the main part 18 toward the axle part 14 so that it overlaps it. The coupling projection 22 is welded to the main part 18 or can alternatively be formed integrally with it. The coupling projection 22 is formed as a solid block, which in the example shown has the shape of a double T. The T's of this shape are arranged side by side, and their upper strokes merge into one another. Alternatively, this can also be described as a pi shape, which resembles the Greek letter pi (π). Accordingly, the coupling projection has two projecting sections 25 connected by a transverse section 27.

[0034] The non-limiting shape shown allows for the suppression of relative movements, in particular axial movements and rotations about an axis not shown, which is perpendicular and orthogonal to the illustrated axis L, A. However, other shapes of the coupling recess 28 and the coupling projection 20 are also possible to achieve similar movement restrictions.

[0035] The coupling projection 22 protrudes away from the axes L, A. Accordingly, its first ends 24, which are connected to and / or merge into the main part 18, are closer to the axes L, A than a free end 26 of the coupling projection 22, which points away from the main part 18. Accordingly, the coupling projection 22 can be described as projecting radially with respect to the axes L, A.

[0036] On an outwardly facing surface that overlaps with the coupling portion 22, the axle part 14 has a coupling recess 28. The coupling recess 28 is formed as a locally depressed area or local depression in the outwardly facing surface. The coupling recess 28 has an outline that is complementary to the exemplary double T- or pi-shaped outline of the coupling projection 22. The outline of the coupling recess 28 is open on one side (see the side surface 37 in Fig. 2), this side facing the steering cylinder 12 and in particular its main part 18. The coupling projection 22 extends along or through the open side, preferably being flush with the outwardly facing surface of the axle part 14 or remaining below this surface.

[0037] In the example shown, outlines of the coupling recess 28 and the coupling projection 22 can be taken into account, which result from the (e.g. orthogonal) projection into a virtual spatial plane which includes the axes L, A or extends parallel thereto.

[0038] The dimensions of the coupling recess 28 and the coupling projection 22 are defined such that not only a shape but also an interference fit is created between them. This interference fit, i.e., the press fit, is sufficiently strong to generate at least a significant portion, if not all, of the forces required for a reliable attachment of the steering cylinder 12 to the axle part 14. This also includes preventing relative movement between these parts when steering forces are generated and / or when other forces are applied during vehicle operation.

[0039] Out of Fig. 1 also shows that the steering cylinder 12 and in particular the main part 18 is not enclosed by the axle part 14 or inserted into its openings, e.g. for centering and / or to establish a mechanical connection. Rather, the steering cylinder 12 is arranged next to the axle part 14 and touches it in defined sections (see the explanation of Fig. 2). This simplifies assembly and, in particular, the construction of the axle part 14. It also enables rapid assembly of the steering cylinder 12 to the axle part 14, including the creation of a press fit between these parts.

[0040] Optionally, the steering cylinder 12 and the axle part 14 are also connected to one another by at least one screw connection 30. In the example shown, two screw connections 30 are present. These extend within the coupling projection 22 and the coupling recess 28 and connect them directly to one another. Specifically, a screw connection 30 is arranged in the area of ​​the protruding sections 25 of the coupling projection 22 and extends through them. Each screw connection 30 is designed to clamp the coupling projection 20 and the coupling recess 28, or in other words, to press them against one another in order to generate additional forces for fastening the master cylinder 12 to the axle part 14. This makes it possible to reduce the required extent of the clamping forces to be generated by the interference fit between the coupling projection 20 and the coupling recess 28.

[0041] Fig. 2 shows a cross-sectional view of the arrangement 10 of Fig. 1. The cross-sectional plane runs orthogonal to the axes L, A and along a screw 32 of one of the screw connections 30. Accordingly, it can be seen that the screw 32 protrudes through the coupling projection 20 into the coupling recess 22. In particular, it extends into a solid volume of the axle part 14, which volume includes a bottom surface 29 of the coupling recess 28.

[0042] More specifically, both the coupling projection 22 and the coupling recess 28 have a threaded bore portion 36, which is formed as a through hole at least in the coupling projection 22. The threaded bore portion 36 is aligned such that they together form a threaded bore 38 of the screw connection 34, which receives a threaded shaft 33. An outwardly facing surface of the coupling projection 22 also includes a bearing surface 44 for a screw head 34 of the screw 32. The bearing surface 44 is formed, for example, as a countersink or, in other words, in the form of a counterbore.

[0043] Out of Fig. 2, but also from Fig. 1 that the screws 32 are aligned at an angle to the axes L, A, this alignment being defined by an orientation of a longitudinal axis S of each screw 32. More precisely, these screw longitudinal axes S extend in a plane which in turn extends orthogonally to the axes L, A. Furthermore, the longitudinal axis S of each screw 32 is aligned substantially orthogonally to the axes L, A and / or may orthogonally intersect a virtual axis (not shown) which extends parallel to the axes L, A. The axes S are examples of second axes about which the interference fit suppresses relative rotation between the coupling recess 28 and the coupling projection 22.

[0044] As a result, no steering forces act on the screws 32 along their respective axes S. Rather, these forces are largely compensated, or in other words, absorbed, by the interference fit between the coupling recess 28 and the coupling projection 22. This means that the number and / or size of the screws 32 can be reduced and / or that the overall connection between the steering cylinder 12 and an axle part 14 is more reliable. This is especially true compared to a scenario in which the screws 32 are aligned along the axes L, A and are thus exposed to the steering forces in their axial direction.

[0045] However, the screws 32 help to prevent the coupling projection 20 from being lifted out of the coupling recess 28, for example in the vertical direction of the Fig. 1. Additionally or alternatively, they provide at least indirect resistance to steering forces by increasing the frictional forces between the coupling projection 20 and the coupling recess 28.

[0046] In addition, the screws 32 in the example shown are aligned so that their screw heads 34 point outwards and in particular vertically outwards or upwards, for example when the arrangement 10 is as shown in Fig. 1. The screw heads 34 are thus easily accessible for tightening and / or loosening.

[0047] Furthermore, the use of two screws 32 can reduce the required surface quality, particularly of the bottom surface 29 of the coupling recess 28. For example, a lack of flatness when generating clamping forces can be at least partially compensated for by the spaced-apart screws 32.

[0048] Out of Fig.2 also shows the following: The axle part 14 has a concavely curved outer surface portion 42, which abuts against a correspondingly curved portion of the main part 18 of the steering cylinder 12. Furthermore, a portion of the inner fluid chamber 44 in the main cylinder 12 is visible, as well as a cross-section of one of the rods 20 located in the fluid chamber 44.

[0049] Furthermore, it can be seen that the coupling projection 22 has a substantially flat underside that rests against the bottom surface 29 of the coupling recess 28. Furthermore, its free end portion 27, and in particular an outwardly directed surface thereof, is in direct contact with a side surface 31 of the coupling recess 28. Relative to the side surface 31, the coupling recess 28 is open, or in other words, not limited. Accordingly, the coupling projection 22 can extend through the respective open side surface 37 into the coupling recess 28.

[0050] The side surface 31 and the adjacent side surfaces that contact the coupling projection 22 can be specially machined fitting surfaces in order to produce the described interference fit between the steering cylinder 12 and the axle part 14.

[0051] In the example shown, the axle part 14 can be relatively compact, e.g. because it does not have its own brackets, through holes or insertion sections for receiving and at least partially enclosing the steering cylinder 12. This means that the size and weight of the axle part 14 can be reduced. This can also result in a specially machined outer surface for contact with the steering cylinder 12 becoming smaller. Furthermore, this can increase the compatibility of the axle part 14 with a larger number of differently configured and / or differently sized steering cylinders 12, in particular if the steering cylinders 12 have similarly sized and shaped coupling projections 20. In such cases, it may be sufficient to adapt a radius and / or the shape of the rather compact contact surface 42 of the axle part 14.

Claims

[1] An arrangement (10) for a steering system of a vehicle, the arrangement comprising: an axle part (14) with a coupling recess (28), and a steering cylinder (12) with a coupling projection (22); wherein the coupling projection (22) is received in the coupling recess (28) and a press fit is formed therebetween. [2] The assembly (10) of claim 1, further comprising at least one screw connection (30) that presses the coupling projection (22) and the coupling recess (28) against each other. [3] Arrangement (10) according to one of the preceding claims, wherein the steering cylinder (12) is adapted to generate steering forces along a first axis (A), wherein the interference fit is configured to hinder relative movement between the coupling recess (28) and the coupling projection (22) along the first axis (A). [4] An assembly (10) according to any preceding claim, wherein the steering cylinder (12) is adapted to generate steering forces along a first axis (A), the interference fit being adapted to hinder relative rotation about a second axis (S). [5] Arrangement (10) according to claim 4, wherein the second axis (S) extends in a plane which is orthogonal to the first axis (A). [6] An assembly (10) according to any one of the preceding claims, wherein the steering cylinder (12) comprises a master cylinder part (18), the coupling projection (22) being welded or otherwise connected to the master cylinder part (18). [7] The assembly (10) of claim 6, wherein the coupling projection (22) is adapted to protrude from and / or relative to an outer peripheral surface of the master cylinder part (18). [8] Arrangement (10) according to claim 2 or according to one of the preceding claims in conjunction with claim 2, wherein the at least one screw connection (30) comprises a screw (32), a threaded bore (38) for receiving a threaded shaft (33) of the screw (30) and a bearing surface (40) for a screw head (34) of the screw (32). [9] Arrangement (10) according to claim 8, wherein at least a part of the threaded bore (38) is encompassed by the axle part (14) and in particular by its coupling recess (28) and wherein the bearing surface (40) is encompassed by the steering cylinder (12) and in particular by its coupling projection (22). [10] Arrangement (10) according to claim 9, wherein the steering cylinder (12) is adapted to generate steering forces along a first axis (A) and the at least one screw (30) extends at an angle to this first axis (A). [11] Arrangement (10) according to one of the preceding claims, wherein the axle part (14) is a housing part. [12] An assembly (10) according to claim 11, wherein the housing part is adapted to receive at least a portion of a differential or other axle component. [13] Arrangement (10) according to one of the preceding claims, wherein the coupling recess (28) is formed as a locally recessed area on an outwardly facing surface of the axle part (14). [14] Arrangement (10) according to claim 13, wherein the locally recessed region has at least one open side surface (37). [15] Steering cylinder (12) with a coupling projection (22) for configuring an arrangement (10) according to one of the preceding claims. [16] Axle part (14) comprising a coupling recess (28) for configuring an arrangement (10) according to one of claims 1 to 15.

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