Combined drawbar shaft

Abstract

The combined tie rod shaft (1) of the present invention has two longitudinal tie rods connected by a torsion profile having a U-shaped or V-shaped double-walled cross-sectional profile in an intermediate length section (11). This cross-sectional profile includes two arms (14, 15) and a vertex (16) connecting these arms. Each arm has an inner wall and an outer wall, which are connected at the free ends (19, 20) of the arms by an arcuate section. A tangential plane (TE) extending longitudinally along the intermediate length section and contacting the two arcuate sections is arranged at an angle (α) between 2° and 10° relative to a transverse plane (HE) in the horizontal plane. The torsion profile is asymmetrical in the intermediate length section, with the two arms of different lengths in the intermediate length section, and the arm at the rear of the combined tie rod shaft (1) being longer than the arm at the front, with reference to its mounting position in a motor vehicle.

Description

Technical Field

[0001] This invention relates to a combined tie rod shaft for motor vehicles. Background Technology

[0002] The combined tie rod axle has proven to be an economical structural form for non-drive rear axles. Two guiding longitudinal tie rods are interconnected by a torsion profile extending laterally between these tie rods. This torsion profile also serves as a stabilizer. A particular advantage of this structure is its excellent lateral guidance during cornering and minimal space requirements, enabling advantageous space allocation.

[0003] A combined tie rod shaft with a torsion profile, known from EP 3 209 511 B1, is prior art. This torsion profile has two spaced-apart arms and a connector linking these arms. The connector is inclined towards one arm in the middle section of the torsion profile. The connector is less inclined or not inclined at all in the outer sections. Furthermore, the torsion profile is waisted along its longitudinal direction, such that the profile width in the middle section is smaller than the profile width in the more outer sections.

[0004] A combined tie-bar type rear axle for motor vehicles, known from EP 0 681 932 B1, is prior art. This rear axle has a torsion profile that is U-shaped for most of its length and has rotationally symmetrical ends, used to influence vehicle performance by rotating the torsion profile relative to the position of the longitudinal tie bar.

[0005] A type of combined tie rod shaft is known from DE 10 2011 011 118 A1. The middle section of the torsion profile has a U-shaped or V-shaped double-walled cross-sectional profile, wherein the U-shaped or V-shaped profile is symmetrical about its centerline and has an opening angle in the range of 5° to 40°.

[0006] In addition, a combined tie rod shaft is known from DE 10 2018 117 994 A1 and US2015 / 035 2922A1, which has a U-shaped or V-shaped double-walled cross-sectional profile in the middle section of a torsion profile.

[0007] Torsional profiles for assembling tie rod shafts are known in KR 10 2010 0009396A and DE 10 2007 058 582 A1, having a U-shaped or V-shaped double-walled cross-sectional profile, including arcuate sections of different sizes in cross-section at the free end of the arm. Summary of the Invention

[0008] Based on existing technology, the purpose of this invention is to improve the lateral stiffness, track stiffness, and camber stiffness of a combined tie rod shaft with a U-shaped or V-shaped double-walled torsion profile without affecting the roll rate, and to improve the performance of the combined tie rod shaft.

[0009] According to the invention, this objective is achieved by a combined tie rod shaft according to the invention. The combined tie rod shaft has two longitudinal tie rods connected by a torsion profile, wherein the torsion profile has a U-shaped or V-shaped double-walled cross-sectional profile in its intermediate length section, the cross-sectional profile including two arms and a vertex connecting these arms, wherein each arm has an inner wall and an outer wall, the inner and outer walls being connected at the free end of the arm by an arcuate section, and a tangential plane extending along the longitudinal direction of the intermediate length section and contacting the two arcuate sections is arranged at an angle between 2° and 10° relative to a transverse plane located in the horizontal plane. The torsion profile is asymmetrical in its intermediate length section, wherein the two arms are of different lengths in the intermediate length section of the torsion profile, and, referring to the mounting position of the combined tie rod shaft in a motor vehicle, the arm located at the rear is longer than the arm located at the front.

[0010] The combined tie rod shaft includes two torsional and bending longitudinal tie rods interconnected by a torsion profile. The torsion profile has a closed U-shaped or V-shaped double-walled cross-sectional profile in its intermediate length section. The U-shaped or V-shaped double-walled cross-sectional profile in the intermediate length section has two arms connected by a apex. Each arm has an inner wall and an outer wall, which are connected at the free end of each arm by an arc-shaped section.

[0011] A tangential plane extending longitudinally along the intermediate length segment and contacting the two arcuate segments on the outside is arranged at an angle α between 2° and 10° relative to a transverse plane located in the horizontal plane.

[0012] This structural design of the torsion profile in its intermediate length section can be achieved by rotating the torsion profile about its longitudinal axis. Another embodiment achieves the design of the invention by designing one arm to be longer than the other. Specifically, referring to the mounting position of the combined tie rod shaft in a motor vehicle, the arm located at the rear is longer than the arm located at the front.

[0013] According to the present invention, the torsion profile is asymmetrical about the intermediate longitudinal axis or the intermediate longitudinal plane in the intermediate length section.

[0014] The structural design of this invention improves lateral stiffness, track stiffness, and camber stiffness without affecting the roll rate. Overall, the performance of the combined tie rod shaft is improved.

[0015] An advantageous embodiment specifies that the torsion profile is rotated about a longitudinal axis in an intermediate length section, wherein an intermediate longitudinal plane extending through the apex and centrally between the arms of the torsion profile is arranged at an angle β between 2° and 10° relative to a vertical plane extending through the apex.

[0016] Particularly advantageous is that the angle α is between 4° and 6°. The angle β is also particularly preferably between 4° and 6°, including both 4° and 6°.

[0017] This invention specifies that the torsion profile is asymmetrical, having arms of different lengths, wherein the torsion profile rotates about its longitudinal axis in a middle length section. The angle β is between 4° and 6°.

[0018] Terms such as “upper” and “lower”, “front” and “rear”, “horizontal” and “vertical” or “longitudinal” and “lateral”, as well as “upper side” and “lower side”, refer to the combined tie rod shaft and its mounting position in the motor vehicle.

[0019] The vehicle coordinate system is a three-dimensional Cartesian coordinate system used to indicate the axes inside the vehicle. The x-axis and y-axis lie in a horizontal plane (= lane plane). The x-axis corresponds to the vehicle's longitudinal axis, is horizontal forward, and is oriented in the direction of the vehicle's movement. The y-axis corresponds to the vehicle's transverse axis and is transverse to the direction of the vehicle's movement. The z-axis is oriented along the vehicle's vertical axis and is perpendicular to the vehicle's xy-plane.

[0020] The transverse plane is a plane perpendicular to the longitudinal axis of the intermediate length section. In terms of the installation position of the combined tie rod shaft in a motor vehicle, the transverse plane corresponds to the xy plane and therefore aligns with the horizontal plane.

[0021] By rotating the torsion profile in its middle length section and / or designing the rear arm of the U-shaped or V-shaped torsion profile to be longer, the rear arm is pushed downwards so that it is lower along the z-axis than the arcuate section at the free end of the front arm, referencing the mounting position of the combined tie rod shaft in the vehicle. This improves lateral stiffness, track stiffness, and camber stiffness without affecting roll rate.

[0022] Rotation in the intermediate length section can be achieved by rotating / twisting the cross-sectional profile of the intermediate length section about the vehicle's transverse axis or the longitudinal axis of the torsion profile. This possibility is particularly suitable for torsion profiles made of tubular material. In this case, the entire torsion profile can be welded to the tie rod in its rotated / twisted position. It is also particularly possible for the torsion profile to undergo shaping after forming a U-shape or V-shape, during which the profile is rotated / twisted except for the end sections. The end sections remain unaffected by rotation or torsion. The connection to the tie rod is achieved using welding techniques commonly used in the field.

[0023] The torsion profile can be made from a tube or from a slab through UO forming. In this case, the torsion profile itself is rotated in the region of the later intermediate length section during the U-shaped drawing step. Therefore, this region is shaped into a U-shape and additionally twisted. The end sections are shaped into U-shapes but not twisted. Then, O-forming is performed and the final welding of the slab edge is carried out along the longitudinal edges on the back of the torsion profile. In this case, the slab edge is welded specifically along the apex. An arcuate shape can be provided on the inside of the intermediate length section, which ensures the weld spacing along the back with the weld seam.

[0024] The end face of the end section has a mating profile that matches the outer profile of the tie rod. The cross-section of the end section is designed to be tubular and non-circular. The end section may have an elliptical or rectangular cross-sectional profile. The upper and lower sidewalls of the end section, extending along the longitudinal direction of the tie rod, are longer than the sidewall segment connecting the upper and lower sidewalls.

[0025] The end segments are relatively short and extend longitudinally along the twisted profile with a length of approximately 20 mm. The end segments are not rotated or twisted. Each end segment transitions into an intermediate length segment via a transition segment. The cross-sectional design, or torsion distribution, in the transition segment changes continuously or discontinuously from the twisted intermediate length segment to an untwisted end segment. Each transition segment has a length corresponding to approximately 1 / 8 of the total length of the twisted profile.

[0026] Since the intermediate length section has rotated relative to the transition section and the end section, while the cross-sections of the transition section and the end section have not rotated around the longitudinal axis, the angle β can also be called the torsion angle.

[0027] One practically advantageous embodiment specifies that the arm located at the rear along the x-axis (vehicle longitudinal axis) relative to the arm located at the front, referring to the mounting position of the combined tie rod shaft, is further recessed or extended. This design is particularly advantageous in torsion profiles made from slabs. In this case, the rear arm has already been lengthened during the U-shaped drawing step. The further steps for producing U-shaped or V-shaped closed torsion profiles remain unchanged.

[0028] The rotation of the cross-sectional profile and the extension of the rear arm can also be implemented together. These measures complement each other in a synergistic manner. The extension of the rear arm need not be so large, and the rotation angle about the longitudinal axis of the torsion profile (which corresponds to the y-axis) need not be chosen to be so large.

[0029] The angle α between the tangential plane and the transverse plane is between 2° and 10°. Similarly, the angle β between the intermediate longitudinal plane and the vertical plane is also between 2° and 10°. Angles α and β are particularly advantageously between 4° and 6°.

[0030] The length difference between the front arm and the rear arm is between 4 mm and 10 mm. It is particularly advantageous that the rear arm is at least 5 mm to 8 mm longer than the front arm.

[0031] The structural design of this invention can increase lateral stiffness, track stiffness, and camber stiffness by 10% to 20% without affecting the roll rate. Attached Figure Description

[0032] The present invention will now be described in detail with reference to the accompanying drawings. The drawings show:

[0033] Figure 1 This is a perspective view of the combined tie rod shaft of the present invention;

[0034] Figure 2 This is a top view of the combined tie rod shaft;

[0035] Figure 3 Similarly, a perspective view is shown of the cross-sectional profile of the torsion profile of the combined tie rod shaft as viewed from below;

[0036] Figure 4 This is a perspective view of the length section of the torsion profile;

[0037] Figure 5 It is the vertical cross-section of the middle length section in the first embodiment;

[0038] Figure 6 It is the vertical cross-section of the intermediate length section in the second embodiment; and

[0039] Figure 7 It is the vertical cross-section of the middle length section in the third embodiment. Detailed Implementation

[0040] Figure 1 A perspective view of a combined tie rod shaft 1 as seen from the rear of a motor vehicle is shown. Figure 2 A top view of the combined tie rod shaft 1 is shown.

[0041] exist Figure 1 A vehicle coordinate system is shown, which can also be used to illustrate the combined tie rod shaft 1 and its components. The x-axis corresponds to the vehicle's longitudinal axis, the y-axis corresponds to the vehicle's transverse axis, and the z-axis corresponds to the vehicle's vertical axis.

[0042] The combined tie rod shaft 1 has two guiding, torsion-resistant, and bending-resistant longitudinal tie rods 2 and 3, which are interconnected by a torsion profile 4. Figure 3 A perspective view of the cross-sectional profile of the torsion profile 4 is shown. Figure 4 The image shows a perspective view of the length section of the torsion profile 4.

[0043] For connection to the vehicle body, the longitudinal tie rods 2 and 3 have front guide bearings 5, which are respectively fixed to the end side of the front length section 6 of the longitudinal tie rods 2 and 3 by welding. The torsion profile 4 is located in front of the wheel center and absorbs all vertical and lateral moments. A spring seat 8 is provided laterally on the rear length section 7 of the longitudinal tie rods 2 and 3, and a wheel carrier 9 is provided on the outer side.

[0044] The longitudinal tie rods 2 and 3 are tubular and have a cross-sectional profile that varies along their length. In the front length section 6, the height of the longitudinal tie rods 2 and 3 measured along the z-direction is greater than the width measured along the y-direction, while in the rear length section 7, the height and width of the longitudinal tie rods 2 and 3 are substantially the same.

[0045] There is a connecting section 10 between the front length section 6 and the rear length section 7 of the longitudinal tie rods 2 and 3. In this connecting section 10, the torsion profile 4 is connected to and welded to one of the longitudinal tie rods 2 and 3 respectively.

[0046] The twisted profile 4 can be made from a slab through UO forming. The twisted profile can also be formed by chipless forming of a tube.

[0047] The torsion profile 4 has an intermediate length segment 11 that extends over the main portion of the total length of the torsion profile 4 (see in particular for this purpose). Figure 2A transition section 12 is abutted on each side of the intermediate length section 11 at the ends facing the torsion profile 4. Each transition section 12 leads into a tubular end section 13. The length of the transition section 12 corresponds to approximately 1 / 8 of the total length of the torsion profile. The end section 13 is relatively short, with a length of approximately 20 mm. The end section 13 has a mating profile on its end side that matches the outer profile of the longitudinal tie rods 2 and 3 in the connecting section 10. The end section 13 is welded to one of the longitudinal tie rods 2 or 3 along this mating profile.

[0048] The torsion profile 4 has a closed U-shaped or V-shaped double-walled cross-sectional profile in its intermediate length section 11, which includes two arms 14, 15 and a vertex 16 connecting the two arms 14, 15. Each arm 14, 15 has an inner wall 17 and an outer wall 18, which extend at a distance from each other. At the free ends 19, 20 of the arms 14, 15, the outer wall 18 and the inner wall 17 are connected to each other by arcuate sections 21, 22, respectively.

[0049] Reference Figures 5 to 7 Three implementations of the combined tie rod shaft 1 by changing its torsion profile 4 are described. The diagrams of the cross-sectional profiles are technically schematic. Figures 5 to 7 In the diagram, the cross-sections of the torsion profiles 4a, 4b, and 4c are shown using solid and dashed lines, respectively. It is important to illustrate the embodiments of the invention using the dashed outline. The solid outline diagram is used to explain various variations, and... Figure 5 and 6 The text is used to illustrate the difference from a torsion profile not constructed according to the present invention.

[0050] In all embodiments of the torsion profiles 4a, 4b, and 4c, the arcuate segment 22 on the free end 20 of the arm 15 located at the rear along the vehicle's longitudinal axis (x-axis) is lower than the arcuate segment 21 on the free end 19 of the arm 14 located at the front, with respect to the vehicle's vertical axis (z-axis). Here, the torsion profile 4 of the combined tie rod shaft 1 is arranged relative to the longitudinal tie rods 2 and 3 such that a tangential plane TE extending along the longitudinal direction LR1 of the intermediate length segment 11 and contacting the two arcuate segments 21 and 22 is arranged at an angle α between 2° and 10° relative to a transverse plane HE located in the horizontal plane. In particular, the angle α is between 4° and 6°.

[0051] exist Figure 5In the illustrated embodiment, the torsion profile 4a is designed to be asymmetrical with reference to its central longitudinal axis MLE or central longitudinal plane. The right arm 15 in the attached plan is the rear arm 15 in the mounting position of the combined tie rod shaft 1, and is designed to be longer than the other arm 14 located at the front. In this way, the tangential plane TE is inclined relative to a transverse plane HE perpendicular to the longitudinal axis LA of the intermediate length segment 11, and this inclination corresponds to an angle α of 4° in the illustrated embodiment.

[0052] exist Figure 6 In the non-inventive torsion profile 4b shown, the torsion profile is designed to be symmetrical about the intermediate longitudinal plane MLE. The torsion profile 4b rotates about the longitudinal axis LA of the intermediate length segment 11 within the intermediate length segment 11. An intermediate longitudinal plane MLE, extending through vertex 16 and centrally between the arms 14 and 15 of the torsion profile 4b, is arranged at an angle β between 2° and 10° relative to a vertical plane VE extending through vertex 16. This angle β is also preferably 4° to 6°.

[0053] In the embodiment of the torsion profile 4b shown, angle α is 6° and angle β is 6°. This rotation produces a 99% camber rate relative to the 100% camber rate of the cross-sectional profile when not rotated. However, the camber stiffness is increased to 115% and the track stiffness to 110% respectively, relative to the 100% camber and lateral stiffness of the unrotated cross-sectional profile.

[0054] exist Figure 7 In the embodiment of the combined tie rod shaft 1 and its torsion profile 4c shown, the torsion profile 4c is asymmetrical and has arms 14, 15 of different lengths. Figure 7 The key feature of the illustrated embodiment is the dashed line drawing of arm 15 at the rear in the right-hand drawing plane, and the tangential plane TE shown by the dashed line. The additionally drawn tangential plane TE' is used to illustrate this embodiment relative to the one shown below. Figure 5 and Figure 6 The implementation shown in the diagram has been modified. The arm 15 located at the rear is longer than the arm 14 located at the front. The tangential plane TE, which extends along the longitudinal direction LR1 of the intermediate length segment 11 and contacts the two arcuate segments 21, 22, is arranged at an angle α relative to the transverse plane HE located in the horizontal plane. This angle can be up to 10°.

[0055] Furthermore, the torsion profile rotates about the longitudinal axis LA in the intermediate length section 11. The intermediate longitudinal plane MLE, extending through vertex 16 and centrally between the arms 14 and 15 of the torsion profile 4, is arranged at an angle (torsion angle) β between 2° and 10° relative to a vertical plane VE extending through vertex 16. In the example shown, the torsion angle β is 4°.

[0056] The length difference between the front arm 14 and the rear arm 15 is preferably about 10 mm. In all embodiments, the lateral stiffness, track stiffness, and camber stiffness are increased by 10% to 20% without significantly affecting the roll rate.

[0057] List of reference numerals

[0058] 1. Combined tie rod shaft

[0059] 2. Tie rod

[0060] 3. Tie rod

[0061] 4. Torsion profiles

[0062] 4a Torsion Profile

[0063] 4b Torsion Profile

[0064] 4c Torsion Profile

[0065] 5 guide bearings

[0066] 6.2, 3. Front longitudinal section

[0067] 7.2, 3 rear longitudinal sections

[0068] 8 Spring seat

[0069] 9-wheel frame

[0070] 10 Connecting Section

[0071] 11. Middle longitudinal section

[0072] 12 Transition Section

[0073] 13 End Sections

[0074] 14 arms

[0075] 15 arms

[0076] 16 vertices

[0077] 17. Inner wall

[0078] 18 outer wall

[0079] 19 14 free end

[0080] 20 15 free end

[0081] 21. Arc-shaped section

[0082] 22. Arc-shaped section

[0083] TE tangential plane

[0084] HE Lateral Plane

[0085] α angle

[0086] β angle

[0087] The longitudinal direction of LR1 11

[0088] LA longitudinal axis

[0089] The middle longitudinal plane of MLE 11

[0090] VE vertical plane

Claims

1. A combined tie rod shaft (1) having two longitudinal tie rods (3) connected by a torsion profile (4; 4a, 4b, 4c), wherein the torsion profile (4; 4a, 4b, 4c) has a U-shaped or V-shaped double-walled cross-sectional profile in an intermediate length section (11), the cross-sectional profile including two arms (14, 15) and a vertex (16) connecting these arms (14, 15), wherein each arm (14, 15) has an inner wall (17) and an outer wall (18), the inner and outer walls being connected at the free ends (19, 20) of the arms (14, 15) by an arcuate section (21, 22), and a tangential plane (TE) extending along the longitudinal direction (LR1) of the intermediate length section (11) and contacting the two arcuate sections (21, 22) is arranged at a first angle (α) between 2° and 10° relative to a transverse plane (HE) located in the horizontal plane, characterized in that: The torsion profile (4; 4a, 4c) is asymmetrical in the intermediate length section (11) of the torsion profile, referring to a central longitudinal plane (MLE) extending through a vertex (16) and centered between the arms (14, 15) of the torsion profile, wherein the two arms (14, 15) are of different lengths in the intermediate length section (11) of the torsion profile (4a, 4c), and the arm (15) located at the rear along the vehicle longitudinal axis, referring to the mounting position of the combined tie rod shaft (1) in the motor vehicle, is longer than the arm (14) located at the front, such that the arcuate section (22) on the free end (20) of the rear arm (15) is lower than the arcuate section (21) on the free end (19) of the front arm (14) referring to the vehicle vertical axis.

2. The combined tie rod shaft (1) according to claim 1, characterized in that: The torsion profiles (4; 4b, 4c) are rotated in the intermediate length section (11) about the longitudinal axis (LA) of the intermediate length section (11), wherein the intermediate longitudinal plane (MLE) is arranged at a second angle (β) between 2° and 10° relative to a vertical plane (VE) extending through the vertex (16).

3. The combined tie rod shaft (1) according to claim 1 or 2, characterized in that: The first angle (α) is between 4° and 6°.

4. The combined tie rod shaft (1) according to claim 2, characterized in that: The second angle (β) is between 4° and 6°.

5. The combined tie rod shaft (1) according to claim 2, characterized in that: The first angle (α) is between 4° and 6°, and the second angle (β) is between 4° and 6°.

6. The combined tie rod shaft (1) according to claim 1 or 2, characterized in that: The length difference between the front arm (14) and the rear arm (15) is between 4 mm and 10 mm.

7. The combined tie rod shaft (1) according to claim 6, characterized in that: The arm (15) located at the rear is at least 5 mm to 8 mm longer than the arm (14) located at the front.

8. The combined tie rod shaft (1) according to claim 1 or 2, characterized in that: The torsion profiles (4; 4a, 4b, 4c) have end segments (13) with a tubular cross-section, which are respectively transitioned to intermediate length segments (11) via a transition segment (12).

9. The combined tie rod shaft (1) according to claim 8, characterized in that: The end segment (13) is non-circular.

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