Steering assembly for vehicle

Abstract

The invention relates to a steering column assembly (10) for a vehicle, comprising an elongate steering shaft (B) mounted for rotation about its longitudinal axis and configured to be attached at one end with a steering member (A). The steering shaft (B) can rotate in two directions from a position corresponding to the straight movement position (SA). The steering column assembly (10) further includes a cam member (20) including a cam surface (22), where the cam member (20) is constrained for rotation with the steering shaft (B), and a cam follower (30) in contact with the cam surface (22). A lever (40) is connected to the lever pivot (44) and arranged to support the cam follower (30), and a spring device (50) is connected to the lever (40) and biases the cam follower (30) into contact with the cam surface (22) via the lever (40). The spring device (50) presses the cam follower (30) so as to displace the cam member (20) in a direction in which the elongated steering shaft (B) returns toward the straight position (SA).

Description

Technical Field

[0001] The present invention relates to a steering assembly for a vehicle and a motor vehicle including the same. More particularly, the present invention relates to a steering assembly for a steer-by-wire vehicle, but is not limited thereto. Background Art

[0002] Traditional vehicle steering systems utilize a constant mechanical connection between the steering wheel and the steering wheel. However, the trend toward steer-by-wire systems breaks the traditional mechanical connection and replaces it with a digital control signal. Specifically, steering input is applied through the steering wheel. A signal is transmitted to the steering wheel shaft actuator based on the steering input to control the movement of the steering rack and the degree to which the steering wheel pivots. Since there is no mechanical connection between the steering wheel and the steering rack, it is usually necessary to provide feedback torque to the steering wheel in the opposite direction of the steering input in order to provide the driver with road feel.

[0003] In a conventional vehicle steering system, when the driver cancels or reduces the torque applied to the steering wheel, the mechanical connection between the steering wheel and the vehicle's steering wheels naturally applies torque to the steering wheel in the opposite direction of the previously applied torque, thereby helping the steering wheel return to its straight-ahead position, but no such torque is generated in a steer-by-wire system. Therefore, when using a steer-by-wire system, the driver must manually return the steering wheel to the straight-ahead position. Summary of the invention

[0004] According to the present invention, a steering column assembly for a vehicle comprises:

[0005] an elongated steering shaft mounted for rotation about its longitudinal axis and configured to be attached to the steering member at one end, the steering shaft being rotatable in two directions from a position corresponding to a straight-ahead position;

[0006] a cam member including a cam surface, wherein the cam member is constrained to rotate with the elongated steering shaft;

[0007] a cam follower, the cam follower in contact with the cam surface;

[0008] a lever connected to a lever pivot and arranged to support the cam follower; and

[0009] a spring device connected to the lever and biasing the cam follower into contact with the cam surface via the lever;

[0010] A spring device urges the cam follower to displace the cam member in a direction to return the elongated steering shaft toward a straight-ahead position.

[0011] By providing a spring device connected to the lever, the spring device can be maintained in compression or tension throughout the rotation of the elongated steering shaft. This provides a constant bias direction in the mechanism, thereby minimizing the possibility and / or effect of kickback. In addition, this arrangement can also increase the service life of the spring device.

[0012] The lever may be arranged to support the cam follower so as to allow it to be displaced about the lever pivot axis upon rotation of the elongate steering column or cam member.

[0013] The steering column assembly may be or may include a steering column return assembly.

[0014] In one embodiment, the spring means is pivotably connected to the lever.

[0015] An end of the spring device may be pivotably connected to the lever.

[0016] The spring device can be pivotally connected to the lever by a hinge. The spring device can be connected to the lever by a ball joint. The spring can include a cap at its end, the cap including a ball socket. The lever can include a ball received in the ball socket.

[0017] A spring arrangement may act on the lever.

[0018] The end of the spring device may act on the lever.

[0019] The end of the spring device may be connected (e.g. pivotally connected) to a pivot (e.g. a spring pivot). The spring device may include a spring anchor. The end of the spring device may be connected to the spring anchor. The spring anchor may include a pivot, e.g. a spring pivot.

[0020] The end of the spring device can be connected to a fixed joint, a fixed location or a fixed spring anchor. The spring anchor can include a fixed joint or a fixed location. The fixed joint or the fixed location can be connected to a fixed location in the steering column assembly.

[0021] The spring pivot may be or may include a fulcrum, such as a spring fulcrum.

[0022] The spring device may include a cap or bracket. The end of the spring device may include a cap or bracket. The cap or bracket can be pivotally connected to a fulcrum or pivot. The cap or bracket can be connected to the spring pivot.

[0023] The rotational axis of the spring pivot may be offset from the rotational axis of the elongated steering shaft.

[0024] The spring means may be or may include a compression spring. The spring means may be or may include a helical spring. The compression spring may be or may include a helical spring or a helical compression spring.

[0025] The spring arrangement may include a plurality of springs, such as springs arranged or mounted coaxially. The spring arrangement may include a pair of springs, such as springs arranged or mounted coaxially. Each spring may have a different diameter.

[0026] The spring means may be or may comprise one or more compression springs.The spring means may be or may comprise a plurality (eg a pair) of compression springs.

[0027] The plurality of compression springs may be identical. The plurality of compression springs may be spaced apart from each other.

[0028] The plurality of compression springs may be arranged parallel to or coaxially with each other. The plurality of compression springs may be connected via a yoke.

[0029] The spring means may be or may comprise a tension spring. The tension spring may be or may comprise a helical spring or a helical tension spring.

[0030] The spring means may be or may comprise one or more extension springs. The spring means may be or may comprise a plurality (eg a pair) of extension springs.

[0031] The plurality of extension springs may be identical. The plurality of extension springs may be spaced apart from each other.

[0032] The plurality of extension springs can be arranged parallel to or coaxially with each other. The plurality of extension springs can be connected via a yoke.

[0033] The spring means may be or may comprise a torsion spring.

[0034] The spring means may be or may comprise one or more torsion springs.The spring means may be or may comprise a plurality of springs (eg a pair of) torsion springs.

[0035] The plurality of torsion springs may be identical. The plurality of torsion springs may be spaced apart from each other.

[0036] The spring means may be preloaded.

[0037] The compression spring may be configured to be in a constant state of compression as the elongated steering column or cam member rotates.

[0038] The extension spring may be configured to be in a constant state of extension as the elongated steering column or cam member rotates.

[0039] The spring arrangement may include one or more elements configured to store energy when displaced, such as coil springs, steel coil springs, resin impregnated carbon structures, fiberglass structures, air springs, air struts, and / or any other suitable resilient components.

[0040] The cam surface may be or may include an annular surface or a radial surface of the cam member.

[0041] The cam member may be an annular cam member or a part-annular cam member.

[0042] The cam surface may be or may include a cam track.

[0043] The cam surface may be or may include a radially inner surface of the cam member. Additionally or alternatively, the cam surface may be or may include a radially outer surface of the cam member.

[0044] The cam follower may be located radially inwardly of the cam surface.

[0045] The spring arrangement may be configured to bias the cam follower radially outwardly into contact with the radially inner surface of the cam member.

[0046] The cam follower may be located radially outwardly of the cam surface.

[0047] The spring arrangement may be configured to bias the cam follower radially inwardly into contact with the radially outer surface of the cam member.

[0048] The cam member may be generally circular when viewed along the longitudinal axis of the elongated steering column.

[0049] The cam member may be mounted eccentrically to the elongated steering column.

[0050] The cam member may be mounted to the end of the elongated steering column.

[0051] The rotational axis of the elongated steering shaft, the rotational axis of the lever pivot and / or the rotational axis of the spring pivot may be substantially parallel to each other and offset from each other.

[0052] In one embodiment, the cam surface comprises an annular end surface or a part-annular end surface of the cam member.

[0053] The annular end surface or part of the annular end surface may be located on the lower end or underside of the cam member. The lower end or underside of the cam member may be the other end or side where the steering member is located in use.

[0054] The centre of the annular cam surface or part of the annular cam surface may be offset from the longitudinal axis of the elongated steering column.

[0055] The height of the cam surface may vary along its length. The height of the cam surface may vary along its arc length.

[0056] The cam surface or cam member may be configured to provide a non-linear torque versus steering angle curve.

[0057] The distance between the cam follower and the spring pivot and / or the lever pivot may vary as the cam member or the elongated steering shaft rotates.

[0058] The distance between the cam surface and the spring pivot and / or the lever pivot may vary as the cam member or the elongated steering shaft rotates. The distance between a portion or part of the cam surface and the spring pivot and / or the lever pivot may vary as the cam member or the elongated steering shaft rotates. The distance between the contact part between the cam follower and the cam surface and the spring pivot and / or the lever pivot may vary as the cam member or the elongated steering shaft rotates.

[0059] The lever may be substantially annular or partially annular.The lever pivot and the cam follower may be located at diametrically opposite sides of the lever.

[0060] The rotational axis of the lever pivot and the rotational axis of the spring pivot may be substantially parallel to each other and offset from each other.

[0061] The rotational axis of the elongated steering column may extend generally transversely to the rotational axis of the lever pivot and the rotational axis of the spring pivot.

[0062] The cam follower may be configured to roll or rotate on the cam surface as the elongated steering column or cam member rotates.

[0063] The cam follower may comprise a roller.

[0064] The cam follower may comprise a roller bearing, a ball bearing or a toroidal bearing.

[0065] The spring pivot may include a bearing. The bearing may include a roller bearing or a ball bearing. The spring pivot may include a plain bushing.

[0066] The lever pivot may include a bearing. The bearing may include a roller bearing or a ball bearing. The lever pivot may include a plain bushing.

[0067] In one embodiment, the cam surface is asymmetric on either side of a position corresponding to a straight-ahead position of the elongated steering column and / or cam member.

[0068] The elongated steering column and / or cam member may be constrained to rotate a maximum of half a turn in either direction from the straight-ahead position.

[0069] In one embodiment, the elongated steering column and / or cam member may be constrained to rotate from the straight-ahead position to an angle between 150 and 180 degrees in either direction, such as an angle between 155 and 175 degrees, or an angle between 160 and 170 degrees. The elongated steering column and / or cam member may be constrained to rotate from the straight-ahead position to 170 degrees in either direction.

[0070] The steering column assembly may include end stops at each end of the cam member, cam surface or cam track, for example to restrict rotation of the elongated steering column and / or cam member.

[0071] The steering column assembly may include a spring housing. The spring may be received in the spring housing. The spring housing may be pivotally connected to the lever.

[0072] The lever pivot may be offset from the axis of rotation of the elongated steering shaft.

[0073] The steering column assembly may be used in a steer-by-wire vehicle.

[0074] According to another aspect of the present invention, there is provided a steering column return assembly for a vehicle, comprising:

[0075] a cam member including a cam surface, wherein the cam member is constrained to rotate with an elongated steering shaft of a vehicle;

[0076] a cam follower, the cam follower in contact with the cam surface;

[0077] a lever connected to a lever pivot and arranged to support the cam follower; and

[0078] a spring device connected to the lever and biasing the cam follower into contact with the cam surface via the lever;

[0079] Wherein, in use, the spring arrangement urges the cam follower to displace the cam member in a direction to return the elongate steering shaft towards a straight-ahead position.

[0080] According to another aspect of the present invention, a vehicle including the above steering column assembly is provided.

[0081] For the avoidance of doubt, any feature described herein is equally applicable to any aspect of the present invention.

[0082] Within the scope of the present application, the various aspects, embodiments, examples and alternatives listed in the preceding paragraphs, claims and / or the following description and drawings, in particular the individual features therein, may be used alone or in any combination. That is, all embodiments and / or features of any embodiment may be combined together in any manner and / or combination, unless such features are incompatible. For the avoidance of doubt, the terms "may", "and / or", "for example", "such as" and any similar terms used herein should be interpreted as non-restrictive, and therefore, any feature described may not necessarily be present. In fact, any combination of optional features may be expressly envisaged without departing from the scope of the present invention, whether or not such features are expressly claimed for protection. The applicant reserves the right to amend any initially filed claims accordingly or to file any new claims, including the right to amend any initially filed claims to make them dependent on and / or include any features of any other claims, even though protection was not initially claimed in this manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0083] Embodiments of the present invention will now be further described, by way of example only, with reference to the accompanying drawings, in which:

[0084] Figure 1 is a schematic diagram of a steer-by-wire system according to the present invention;

[0085] Figure 2 is with Figure 1 A schematic diagram of a first embodiment of a steering column assembly for use with a steer-by-wire system;

[0086] Figure 3 is with Figure 1 A plan view of a second embodiment of a steering column assembly for use with a steer-by-wire system showing the elongated steering shaft rotating counterclockwise from a straight-ahead position;

[0087] Figure 4 is with Figure 1 A schematic plan view of a third embodiment of a steering column assembly for use with a steer-by-wire system;

[0088] Figure 5 is with Figure 1 A schematic plan view of a fourth embodiment of a steering column assembly for use with a steer-by-wire system;

[0089] Figure 6 is with Figure 1 A schematic plan view of a fifth embodiment of a steering column assembly for use with a steer-by-wire system;

[0090] Figure 7 is with Figure 1 A schematic diagram of a sixth embodiment of a steering column assembly for use with a steer-by-wire system;

[0091] Figure 8 is with Figure 1 A schematic diagram of a seventh embodiment of a steering column assembly for use with a steer-by-wire system;

[0092] Fig. 9 is with Figure 1 A schematic diagram of an eighth embodiment of a steering column assembly for use with a steer-by-wire system;

[0093] Fig.10 is with Figure 1 A schematic diagram of a ninth embodiment of a steering column assembly for use with a steer-by-wire system;

[0094] Fig.11 is with Figure 1 A side view schematically showing a tenth embodiment of a steering column assembly for use with a steer-by-wire system;

[0095] Fig.12 yes Fig.11 An exploded perspective view of a steering column assembly;

[0096] Fig.13 yes Fig.11 An exploded side view of a steering column assembly;

[0097] Fig.14 yes Figures 11 to 13 A vertical cross-sectional view of a steering column assembly at a first steering angle; and

[0098] Fig.15 yes Figures 11 to 13 A vertical cross-sectional view of a steering column assembly at a second steering angle. DETAILED DESCRIPTION

[0099] Figure 1 A steer-by-wire system S for a vehicle is shown incorporating a steering column assembly 10 according to the present invention. The steer-by-wire system S comprises a hand wheel actuator in the form of a steering wheel A to allow the driver of the vehicle to provide input steering commands. The steering wheel A is connected to the end of an elongated steering shaft B.

[0100] The steering input applied through the steering wheel A is measured by a steering sensor which forms part of the steering column assembly, such as Figure 1 Schematically shown at C in FIG. A signal representing the steering input (i.e., the rotation of the steering wheel A and the elongated steering shaft B) is transmitted from the sensor C to the electronic control unit (ECU) D, which in turn controls the steering wheel axle actuator E. The steering wheel axle actuator E applies the steering input to the steering wheel axle F and thus steers the steering wheel G according to the rotational position of the steering wheel A.

[0101] The electronic control unit D is also configured to provide current to a torque feedback motor H which is connected to the elongated steering shaft B and applies torque in a direction opposite to the torque applied at the steering wheel A in order to provide "road feel" to the driver.

[0102] A steering column return assembly J is also mounted on the elongated steering shaft B. In this embodiment, the steering column return assembly J is mounted between the steering wheel A and the sensor C, but may be mounted at other locations on the elongated steering shaft B. The purpose of the steering column return assembly is to apply torque to the elongated steering shaft B (and steering wheel A) in a direction opposite to the direction in which the driver applies torque, to assist the driver in returning the elongated steering shaft B (and steering wheel A) to the straight ahead position.

[0103] Figure 2 Shows the formation Figure 1 A first embodiment of a steering column assembly 10 as part of a steer-by-wire system S is shown. The steering column assembly 10 includes an elongated steering shaft B mounted to rotate about its longitudinal axis. Figure 2 As shown, the elongated steering shaft B is rotatable in two directions from a position corresponding to the straight-ahead position SA.

[0104] The cam member 20 is configured to rotate with the elongated steering shaft B and includes a cam surface 22 on its inner surface. The cam follower 30 is located at the end of the lever 40, contacting the cam surface 22. The compression spring 50 is connected between the ends of the lever 40, biasing the cam follower 30 to contact the cam surface 22 via the lever 40. In use, the compression spring 50 pushes the cam follower 30 to displace the cam member 20 in a direction to return the elongated steering shaft B toward the straight position SA.

[0105] The cam member 20 is mounted eccentrically relative to the elongated steering shaft B. In this embodiment, the cam surface 22 is formed on the inner surface of the cam member 20. Figure 2 , but the cam member 20 is configured to be oriented toward the elongated steering axis B ( Figure 1 ) provides a spring return force or return torque, which moves along with the steering wheel A ( Figure 1 ) changes in a nonlinear manner with the rotation angle of the cam member 20. Typically, the cam member 20 is not completely circular or symmetrical. In addition, although not shown, the cam surface 22 is asymmetrical on both sides of the position corresponding to the straight position of the cam member 20.

[0106] The cam follower 30 is located radially inwardly of the cam surface 22 and is a roller bearing in this embodiment. The cam follower 30 is rotatably mounted near the free end 42 of the lever 40 and has an axis of rotation 32. The lever 40 may include a plate, such as Figure 3 shown, but in Figure 2 The lever 40 is connected to a lever pivot 44 at its other end 46. The lever pivot 44 is connected to a fixed position in the steering column assembly 10.

[0107] In the present embodiment, the compression spring 50 is a coil spring having a first end 52 pivotally connected to the lever 40 between the ends 42 and 46 of the lever. A second end 54 of the compression spring 50 is pivotally connected to a spring pivot 56. In the present embodiment, the compression spring 50 is preloaded so that it continuously biases the cam follower 30 away from the spring pivot 56 and into contact with the cam surface 22.

[0108] The rotational axes of the elongated steering shaft B, the lever pivot 44 and the spring pivot 56 are generally parallel to and offset from one another.

[0109] In use, when the elongated steering shaft B is rotated in either direction from the straight-ahead position SA, the cam member 20 and the cam surface 22 also rotate therewith. The cam follower 30 is configured to roll on the cam surface 22, and due to the eccentrically mounted cam member 20, the distance between the spring pivot 56 and the rotation axis 32 of the cam follower 30 changes as the elongated steering column B rotates. The lever 40 supports the cam follower 30 to allow it to be displaced about the lever pivot 44. Since the compression spring 50 is pivotally connected to the lever 40 and the spring pivot 56, when the cam follower 30 is displaced, the loading direction of the spring is also adjusted accordingly.

[0110] exist Figure 2 In the case of the arrangement, if the elongated steering column B is rotated clockwise from the straight-ahead position SA, the distance between the cam follower 30 and the spring pivot 56 is reduced. This will cause the lever 40 to rotate clockwise about the lever pivot 44, thereby causing the preloaded compression spring 50 to contract and further compress. As the lever 40 rotates clockwise, the biasing force applied by the compression spring 50 to the lever 40 and therefore to the cam follower 30 increases. As a result, the contact force between the cam surface 22 and the cam follower 30 increases. The direction of the contact force is generally the normal direction of the cam surface 22, and the geometry or construction of the cam surface 22 pushes the cam follower 30 to shift the cam member 20 and the elongated steering shaft B in a counterclockwise direction toward the straight-ahead position SA.

[0111] Understandable, although Figure 2 The steering column assembly 10 in FIG. 1 shows a single compression spring 50, but this is not necessarily the case. In some embodiments, the compression spring may include a pair of compression springs, as follows: Figure 3 The steering column assembly may include more than one spring arranged coaxially, in parallel and / or in series.

[0112] It will also be appreciated that instead of the compression spring 50 being connected at its second end 54 to the spring pivot 56, it may be connected to the fixed location 556, such as Figure 7 The fixing portion 556 can be connected to a fixing portion in the steering column assembly 510 or a fixing portion in the housing (not shown) of the compression spring 550. Figure 7 In the case of steering column assembly 510 , compression spring 550 may bend along its longitudinal axis to accommodate displacement of lever 540 during rotation of cam member 520 . Figure 7 The steering column assembly 510 and Figure 2 The steering column assembly 10 is similar to the steering column assembly 10 of the present invention, wherein similar features are represented by the same reference numerals plus "500" and are not repeated for the sake of brevity.

[0113] Figure 3 Shows the formation Figure 1 A second embodiment of a steering column assembly 110 as part of a steer-by-wire system S. The steering column assembly 110 is Figure 2 The steering column assembly is similar to that of the present invention, wherein similar features are represented by the same figure numbers plus "100", and for the sake of brevity, only the differences are described in detail below.

[0114] The cam member 120 is configured to rotate with the elongated steering shaft B and has a generally circular outer periphery 126 when viewed along the longitudinal axis L. The cam member 120 includes asymmetric cam surfaces 122 on either side of a position corresponding to the straight-ahead position of the cam member 120 .

[0115] The cam follower 130 is rotatably mounted to a first vertex 146a of a generally triangular plate 148 of the lever 140 and contacts the cam surface 122. The plate 148 is connected to the lever pivot 144 at a second vertex 146b thereof.

[0116] In the present embodiment, a pair of compression springs 150a, 150b are provided, which are connected at their respective first ends to the opposite ends of a generally U-shaped mounting yoke 152. The mounting yoke 152 is pivotally connected to the third vertex 146c of the plate 148 so that its axis of rotation is centrally located between the longitudinal axes of the compression springs 150a and 150b. The mounting yoke 152 is connected to the plate 148 radially outward of the axis of rotation 132 of the cam follower 130.

[0117] The respective second end 154 of each of the compression springs 150a and 150b is connected to an opposite end of another generally U-shaped mounting yoke 157. The mounting yoke 157 is connected to a spring pivot 156. The other mounting yoke 157 is pivotally mounted so that its axis of rotation is centrally located between the longitudinal axes of the compression springs 150a and 150b.

[0118] Compression springs 150 a , 150 b bias the cam follower 130 into contact with the cam surface 122 via a mounting yoke 152 connected to the lever 140 .

[0119] The rotational axes of the elongated steering shaft B, the lever pivot 144 and the spring pivot 156 are generally parallel to and offset from one another.

[0120] Since the compression springs 150a, 150b are pivotably connected to the lever 140 and the spring pivot 156 via the mounting yokes 152, 157, their rotations are coupled such that the loading direction of the springs is adjusted when the cam follower 130 is displaced.

[0121] exist Figure 3 In the case of the arrangement of FIG. 1 , the elongated steering column B is shown in a position that has been rotated counterclockwise from the straight-ahead position. Figure 3 position, the distance between the cam follower 130 and the spring pivot 156 decreases, causing the lever 140 to rotate clockwise about the lever pivot 144. This will cause the preloaded compression springs 150a, 150b to compress. When the lever 140 rotates clockwise, the biasing force applied by the compression springs 150a, 150b to the lever 140 and therefore to the cam follower 130 increases. Therefore, the contact force between the cam surface 122 and the cam follower 130 increases. The direction of the contact force is generally the normal direction of the cam surface 122, and the geometry or construction of the cam surface 122 pushes the cam follower 130 to shift the cam member 120 and the elongated steering shaft B in a clockwise direction toward the straight-ahead position.

[0122] Figure 4 Shows the formation Figure 1 A third embodiment of a steering column assembly 210 as part of a steer-by-wire system S. The steering column assembly 210 is Figure 2 The steering column assembly is similar to that of the present invention, wherein similar features are represented by the same reference numerals plus "200", and for the sake of brevity, only the differences are described in detail below.

[0123] Figure 2 The main difference between the steering column assembly 10 and the steering column assembly 210 is that in the present arrangement the spring is a tension spring 250 rather than a compression spring.

[0124] In this embodiment, the extension spring 250 is a coil spring having a first end 252 pivotally connected to the lever 240 between the two ends 242, 246 of the lever. The second end 254 of the extension spring 250 is connected to a spring pivot 256, which is located at a position adjacent to the lever pivot 244. Figure 2In this embodiment, the tension spring 250 is preloaded so that it continuously biases the cam follower 230 toward the spring pivot 256 and contacts the cam surface 222. Although not shown, the cam surface 222 is asymmetrical on both sides of the position corresponding to the straight position of the cam member 220.

[0125] In use, the tension spring 250 urges the cam follower 230 to displace the cam member 220 in a direction to return the elongated steering axis B towards the straight-ahead position SA.

[0126] The rotational axes of the elongated steering shaft B, the lever pivot 244 and the spring pivot 256 are generally parallel to and offset from one another.

[0127] exist Figure 4 In the case of the arrangement, if the elongated steering column B is rotated clockwise from the straight-ahead position SA, the distance between the cam follower 230 and the spring pivot 256 will increase. This will cause the lever 240 to rotate clockwise about the lever pivot 244, causing the preloaded tension spring 250 to lengthen. When the lever 240 rotates clockwise, the biasing force applied by the tension spring 250 to the lever 240 and therefore to the cam follower 230 increases. Therefore, the contact force between the cam surface 222 and the cam follower 230 increases. The direction of the contact force is generally the normal direction of the cam surface 222, and the geometry or construction of the cam surface 222 pushes the cam follower 230 to shift the cam member 220 and the elongated steering shaft B in the counterclockwise direction toward the straight-ahead position SA.

[0128] Figure 5 Shows the formation Figure 1 A fourth embodiment of a steering column assembly 310 as part of a steer-by-wire system S. The steering column assembly 310 is Figure 2 The steering column assembly is similar to that of the present invention, wherein similar features are represented by the same reference numerals plus "300", and for the sake of brevity, only the differences are described in detail below.

[0129] Figure 2 The main difference between the steering column assembly 10 and the steering column assembly 310 is that in this arrangement, the cam surface 322 is formed on the radially outer surface of the cam member 320, and the spring is a tension spring 350 instead of a compression spring. The cam follower 330 is also located radially outside the cam member 320.

[0130] exist Figure 5In the case of the arrangement, if the elongated steering column B is rotated clockwise from the straight-ahead position SA, the distance between the cam follower 330 and the spring pivot 356 will increase. This will cause the lever 340 to rotate counterclockwise about the lever pivot 344, causing the preloaded tension spring 350 to lengthen. When the lever 340 rotates counterclockwise, the biasing force applied by the tension spring 350 to the lever 340 and therefore to the cam follower 330 increases. Therefore, the contact force between the cam surface 322 and the cam follower 330 increases. The direction of the contact force is generally the normal direction of the cam surface 322, and the geometry or construction of the cam surface 322 pushes the cam follower 330 to shift the cam member 320 and the elongated steering shaft B in the counterclockwise direction toward the straight-ahead position SA.

[0131] Figure 6 Shows the formation Figure 1 A fifth embodiment of a steering column assembly 410 as part of a steer-by-wire system S. The steering column assembly 410 is Figure 5 The steering column assembly 310 is similar to the steering column assembly 310, wherein similar features are represented by the same figure numbers plus "100", and for the sake of brevity, only the differences are described in detail below.

[0132] Figure 5 The steering column assembly 310 and Figure 6 The main difference between the steering column assembly 410 of FIG. 4 is that in this arrangement the spring is a compression spring 450 rather than a tension spring.

[0133] The second end 454 of the compression spring 450 is connected to a spring pivot 456 which is located between the lever pivot 444 and the spring pivot 456. Figure 5 In the present embodiment, the compression spring 450 is preloaded so that the cam follower 430 is continuously biased away from the spring pivot 456 and in contact with the cam surface 422.

[0134] exist Figure 6 In the case of the arrangement, if the elongated steering column B is rotated clockwise from the straight-ahead position SA, the distance between the cam follower 430 and the spring pivot 456 is reduced. This will cause the lever 440 to rotate counterclockwise about the lever pivot 444, causing the preloaded compression spring 450 to contract or compress. When the lever 440 rotates counterclockwise, the biasing force applied by the compression spring 450 to the lever 440 and therefore to the cam follower 430 increases. Therefore, the contact force between the cam surface 422 and the cam follower 430 increases. The direction of the contact force is generally the normal direction of the cam surface 422, and the geometry or construction of the cam surface 422 pushes the cam follower 430 to shift the cam member 420 and the elongated steering shaft B in the counterclockwise direction toward the straight-ahead position SA.

[0135] It will also be appreciated that instead of the compression spring 450 being connected at its second end 454 to the spring pivot 456, it may be connected to the fixed location 656, such as Figure 8 The fixing portion 656 can be connected to a fixing portion in the steering column assembly 610 or a fixing portion in the housing (not shown) of the compression spring 650. Figure 8 In the case of steering column assembly 610 , compression spring 650 may bend along its longitudinal axis to accommodate displacement of lever 640 during rotation of cam member 620 . Figure 8 The steering column assembly 610 and Figure 6 The steering column assembly 410 is similar to the steering column assembly 410, wherein like features are represented by the same reference numerals plus "200" and are not repeated for the sake of brevity.

[0136] Fig. 9 Shows the formation Figure 1 An eighth embodiment of a steering column assembly 710 of a portion of a steer-by-wire system S is provided.

[0137] Steering column assembly 710 and Figure 4 The steering column assembly is similar to that of the present invention, wherein similar features are represented by the same reference numerals plus "500", and for the sake of brevity, only the differences are described in detail below.

[0138] Fig. 9 The main difference between the steering column assembly 710 and the steering column assembly 210 is that in this arrangement the spring is a torsion spring 750 rather than a tension spring.

[0139] A first end 752 of the torsion spring 750 contacts and acts on the lever 740 between the ends 742, 746 of the lever. A second end 754 of the torsion spring 750 is connected to a fixed portion 756 of the steering column assembly 710. The torsion spring 750 applies a torque about the lever pivot 744 and is arranged so that the torque applied to the lever 740 increases as the elongated steering shaft B rotates away from the straight-ahead position SA. In this embodiment, the torsion spring 750 is preloaded so that it continuously biases the cam follower 730 into contact with the cam surface 722. Although not shown, the cam surface 722 is asymmetrical on both sides of the position corresponding to the straight-ahead position of the cam member 720.

[0140] In use, the torsion spring 750 urges the cam follower 730 to displace the cam member 720 in a direction to return the elongated steering axis B towards the straight-ahead position SA.

[0141] Fig.10 Shows the formation Figure 1 A ninth embodiment of a steering column assembly 810 of a portion of a steer-by-wire system S is provided.

[0142] Steering column assembly 810 and Figure 5 The steering column assembly is similar to that of the present invention, wherein similar features are represented by the same reference numerals plus "500", and for the sake of brevity, only the differences are described in detail below.

[0143] Fig.10 The main difference between the steering column assembly 810 and the steering column assembly 310 is that in this arrangement the spring is a torsion spring 850 rather than a tension spring. Fig.10 The torsion spring 850 is Fig. 9 The torsion spring 750 operates in a similar manner and will not be described in detail.

[0144] In use, the tension spring 850 urges the cam follower 830 to displace the cam member 820 in a direction to return the elongated steering axis B towards the straight-ahead position SA.

[0145] Figures 11 to 15 Shows the formation Figure 1 The tenth embodiment of a steering column assembly 910 as part of a steer-by-wire system S. The steering column assembly 910 includes an elongated steering shaft B mounted to rotate about its longitudinal axis. Fig.11 As shown, the elongated steering shaft B can be rotated in two directions from a position corresponding to the straight-ahead position.

[0146] The partially annular cam member 920 is configured to rotate with the elongated steering shaft B and includes a partially annular cam surface 922. The cam follower 930 is located on one side of the partially annular lever 940 and contacts the cam surface 922. A compression spring 950 is connected between the ends of the lever 940, biasing the cam follower 930 to contact the cam surface 922 via the lever 940.

[0147] The cam member 920 is generally circular when viewed along the longitudinal axis L and is mounted eccentrically relative to the elongated steering axis B. The cam member 920 is arranged so that when the lever 940 is articulated, the cam follower 930 contacts the cam surface 922. In this embodiment, the cam surface 922 is formed on a partially annular end surface of the annular wall 924. The cam surface 922 extends between the ends 922a, 922b and has a height H (e.g., Fig.11 The change in height H can be configured so that the return torque applied to the elongated steering shaft B varies with the steering wheel A ( Figure 1 ) changes in a nonlinear manner with the rotation angle.

[0148] The cam follower 930 contacts the cam surface 922 and in this embodiment is a roller bearing. The cam follower 930 is rotatably mounted on one side 942 of the lever 940 and has an axis of rotation 932. The lever 940 is partially annular and is connected to a lever pivot 944 via a pair of spaced apart lugs 945. The lever pivot 944 and the cam follower 930 are located at diametrically opposite sides of the lever 940.

[0149] In this embodiment, the compression spring 950 is a coil spring enclosed in a cylindrical housing 970. The cylindrical housing 970 is rotatably connected to the lever 940 via a pair of opposed protruding lugs 972. The spring compression spring 950 has a first end 952 located within an annular channel 974 at the base 970a of the housing 970 and is pivotally connected to the lever 940 via the housing 970. Each lug in the pair of lugs 972 extends from a support ring 976 and is received in a corresponding recess 947 of the lever 940. The second end 954 of the compression spring 950 extends from the open end 970b of the housing 970 and is provided with a cap 959 that is connected to the spring pivot 956 via a pair of spaced lugs 959a. In this embodiment, the compression spring 950 is preloaded so that it continuously biases the cam follower 930 away from the spring pivot 956 and in contact with the cam surface 922.

[0150] The cylindrical housing 970 may enable a more compact arrangement in the direction of the longitudinal axis L.

[0151] The rotation axis of the elongated steering shaft B extends generally transversely to the rotation axis of the lever pivot 944 and the rotation axis of the spring pivot 956. The rotation axis of the lever pivot 944 and the rotation axis of the spring pivot 956 are generally parallel to each other and offset from each other. In addition, the longitudinal axis Y of the compression spring 950 extends at a certain angle relative to the longitudinal axis L of the elongated steering shaft B.

[0152] Fig.14 The steering column assembly 910 is shown with the elongated steering axis B in a straight-ahead position. Fig.15 The steering column assembly 910 is shown when the elongated steering axis B has been rotated 150 degrees from the straight-ahead position.

[0153] In use, when the elongated steering axis B is Fig.14 The straight position is rotated in either direction to Fig.15, the cam member 920 and the cam surface 922 also rotate accordingly. The cam follower 930 is configured to roll on the cam surface 922, and due to the change in the height H of the cam surface 922, the distance between the spring pivot 956 and the rotation axis 932 of the cam follower 930 is reduced. The lever 940 supports the cam follower 930 to allow it to shift around the lever pivot 944. The lever 940 also pivotally supports the cylindrical housing 970 via the protruding lug 972.

[0154] Rotation of the elongated steering axis B will cause the lever 940 to rotate upward about the lever pivot 944 ( Fig.14 and Fig.15 The lever 940 is rotated clockwise (clockwise in the figure), thereby displacing the cylindrical housing 970 toward the spring pivot 956 and causing the preloaded compression spring 950 to contract and further compress. When the lever 940 is rotated clockwise, the biasing force applied by the compression spring 950 to the lever 940 and thus to the cam follower 930 via the cylindrical housing 970 increases. As a result, the contact force between the cam surface 922 and the cam follower 930 increases. The direction of the contact force is generally the normal direction of the cam surface 922, and the geometry or construction of the cam surface 922 pushes the cam follower 930 to cause the cam member 920 and the elongated steering axis B to move toward Fig.14 The straight position is shifted.

[0155] Because the compression spring 950 is pivotally connected to the lever 940 and the spring pivot 956, when the cam follower 930 is displaced, the loading direction of the spring is also adjusted.

[0156] Those skilled in the art will appreciate that many variations may be made to the above embodiments without departing from the scope of the present invention.

[0157] Those skilled in the art will also appreciate that any combination of the above features and / or features shown in the accompanying drawings has significant advantages over the prior art and is therefore within the scope of the invention described herein.

Claims

1. A steering column assembly for a vehicle, comprising: an elongated steering shaft mounted for rotation about its longitudinal axis and configured to be attached to the steering member at one end, the steering shaft being rotatable in two directions from a position corresponding to a straight-ahead position; a cam member including a cam surface, wherein the cam member is constrained to rotate with the steering shaft; a cam follower, the cam follower in contact with the cam surface; a lever connected to a lever pivot and arranged to support the cam follower; as well as a spring device connected to the lever and biasing the cam follower into contact with the cam surface via the lever; A spring device urges the cam follower to displace the cam member in a direction to return the elongated steering shaft toward a straight-ahead position.

2. A steering column assembly according to claim 1, wherein the spring device is pivotally connected to the lever.

3. A steering column assembly according to claim 2, wherein an end of the spring device is connected to a spring pivot.

4. The steering column assembly of claim 2, wherein an end of the spring device is connected to a fixed spring anchor.

5. A steering column assembly according to any preceding claim, wherein the spring means comprises a compression spring.

6. A steering column assembly as claimed in claim 5, wherein the spring means comprises a pair of spaced apart compression springs.

7. A steering column assembly according to any one of claims 1 to 4, wherein the spring means comprises a tension spring.

8. A steering column assembly according to any one of claims 1 to 4, wherein the spring means comprises a torsion spring.

9. A steering column assembly according to any preceding claim, wherein the cam surface comprises a radially inner surface of the cam member.

10. A steering column assembly according to any one of claims 1 to 8, wherein the cam surface comprises a radially outer surface of the cam member.

11. A steering column assembly according to claim 9 or 10 as appended to claim 3, wherein the axes of rotation of the elongate steering shaft, the lever pivot and the spring pivot are substantially parallel to and offset from one another.

12. A steering column assembly according to any one of claims 1 to 8, wherein the cam surface comprises an annular end surface or a part annular end surface of the cam member.

13. The steering column assembly of claim 12, wherein the height of the cam surface varies along its length.

14. A steering column assembly according to claim 12 or 13, wherein the lever is generally annular or part annular, and wherein the lever pivot and cam follower are at diametrically opposite sides thereof.

15. A steering column assembly according to any one of claims 12 to 14 when dependent on claim 3, wherein the axis of rotation of the lever pivot and the axis of rotation of the spring pivot are substantially parallel to and offset from each other.

16. The steering column assembly of claim 15, wherein the rotational axis of the elongated steering column extends generally transversely to the rotational axes of the lever pivot and the spring pivot.

17. A steering column assembly according to any preceding claim, wherein the cam follower is arranged to roll on the cam surface as the cam member rotates.

18. The steering column assembly of claim 17, wherein the cam follower comprises a roller bearing or a ball bearing.

19. A steering column assembly according to any one of the preceding claims, wherein the cam surface is asymmetric on either side of a position corresponding to a straight-ahead position of the cam member.

20. A steering column assembly according to any preceding claim, wherein the elongate steering column is constrained to rotate a maximum of half a turn in either direction from a straight ahead position.

21. A steering column assembly according to any one of the preceding claims, comprising a spring housing and wherein a spring is received within the spring housing, wherein the spring housing is pivotably connected to the lever.

22. A steering column assembly according to any preceding claim, wherein the lever pivot is offset from the axis of rotation of the elongate steering shaft.

23. A steering column assembly according to any preceding claim for use in a steer-by-wire vehicle.

24. A steering column return assembly for a vehicle, comprising: a cam member including a cam surface, wherein the cam member is constrained to rotate with an elongated steering shaft of a vehicle; a cam follower, the cam follower in contact with the cam surface; a lever connected to a lever pivot and arranged to support the cam follower; as well as a spring device connected to the lever and biasing the cam follower into contact with the cam surface via the lever; Wherein, in use, the spring arrangement urges the cam follower to displace the cam member in a direction to return the elongate steering shaft towards a straight-ahead position.

25. A vehicle comprising a steering column assembly according to any one of claims 1 to 23 or a steering column return assembly according to claim 24.

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