Combined pull rod shaft for motor vehicle
By designing pressure relief grooves in the torsional profile of the combined tie rod shaft of the motor vehicle to absorb the stress in the connecting area of the longitudinal tie rod and the torsional profile, the problem of stress affecting the weld life in the prior art is solved, and the service life and cost reduction of the combined tie rod shaft are achieved.
Patent Information
- Application Number
- CN202411587203.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-11-10
- Filing Date
- 2024-11-08
- Publication Date
- 2025-05-13
AI Technical Summary
The stress generated by existing motor vehicle combination pull rod axles in the connection area between the longitudinal pull rod and the torsional profile will affect the service life of the weld, thereby affecting the overall service life of the combined pull rod axles.
At least one pressure relief groove is designed in the weld area of the longitudinal side end section of the torsion profile, extending longitudinally and oriented laterally to the weld to absorb bending moments and stresses transmitted by the wheels.
Through the design of the pressure relief groove, the stress acting on the weld is reduced and the service life of the weld is extended, thereby improving the overall service life of the combined tie rod shaft while avoiding increasing the weight and cost of the combined tie rod shaft.
Smart Images
Figure CN119974874A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a twist-joint axle for a motor vehicle according to the features of the preamble of claim 1 . Background Art
[0002] In the prior art, there are known conventional track axles for motor vehicles, which connect the wheels to the vehicle body and are mostly used as rear axles. Track axles mostly consist of two bending- and torsion-resistant longitudinal arms and a torsion profile connecting the two longitudinal arms. Special requirements are placed on the corresponding torsion profiles. Their end sections should be designed to be as rigid as possible to avoid undesired changes in the wheelbase and camber angle. At the same time, however, they should also be torsionally flexible, which is mostly achieved by a torsionally flexible middle section of the torsion profile.
[0003] The torsion profile is usually joined to the trailing arm at its respective longitudinal end section by means of a weld seam in a material-locking manner. In the transition area between the trailing arm and the torsion profile and in particular at and in the weld seam, high stress peaks sometimes occur during operation of the motor vehicle. These high stress peaks are caused, for example, by vertical forces transmitted by the wheels to the track arm axle and can affect the service life of the weld seam and thus of the track arm axle itself.
[0004] In order to increase the durability of the track rod axle, there are two known possibilities in the prior art that reduce the stresses that occur in the connection area between the longitudinal tie rod and the torsion profile. On the one hand, the thickness or material thickness of the longitudinal end section of the torsion profile and the adjacent longitudinal tie rod can be increased, for example by means of additional reinforcement plates. However, this increases the costs and also the weight of the track rod axle, which is detrimental to the driving performance and fuel consumption of the motor vehicle. On the other hand, the weld seams can be processed by shot peening, but this also significantly increases the production costs of the track rod axle. Summary of the invention
[0005] Starting from the prior art, the object of the invention is to provide a combined control arm axle of the lowest possible weight, wherein during operation of the motor vehicle provided as the field of application, the stresses acting on the weld seam in the connection region between the trailing arm and the torsion profile are reduced.
[0006] This object is achieved by a twist-rod shaft having the features of claim 1 .
[0007] Advantageous configuration variants are the subject matter of the dependent claims.
[0008] The tie rod axle for a motor vehicle according to the invention has two longitudinal arms connected by a torsion profile. When the tie rod axle is used in a motor vehicle, the two longitudinal arms of the tie rod axle are oriented in the longitudinal direction of the vehicle, while the torsion profile connects the two longitudinal arms to one another in the transverse direction of the vehicle. The tie rod axle connects the wheels to the body of the motor vehicle. The torsion profile is joined to the longitudinal arms by means of a weld seam at its end section on the longitudinal side in a materially bonded manner. The weld seam in particular follows the geometry of the components to be connected.
[0009] The essence of the invention is that the torsion profile has at least one pressure relief groove in the region of the weld in the end section of its corresponding longitudinal side. The pressure relief groove has a longitudinal extension and is oriented transversely to the direction of the weld in the direction of its longitudinal extension. The torsion profile is loaded with a bending moment by the vertical force transmitted by the wheel to the tie rod shaft, which causes stresses in the transition area between the longitudinal tie rod and the torsion profile and in particular at and in the weld connecting the longitudinal tie rod and the torsion profile. This can have an adverse effect on the service life of the weld and thus on the service life of the tie rod shaft. With the help of the pressure relief groove arranged according to the invention, the stress acting on the weld is reduced by absorbing it by the pressure relief groove. In this way, the service life of the weld and thus the service life of the tie rod shaft can be increased. It has been shown that the orientation of the pressure relief groove transversely to the direction of the weld is particularly conducive to absorbing the generated stresses.
[0010] The arrangement of the pressure relief groove according to the present invention does not increase the weight of the combined tie rod shaft, and the construction of the pressure relief groove in the torsion profile is conducive to reducing costs.
[0011] The stress relief groove has a width on its side oriented toward the weld seam, which width corresponds essentially to the length of a weld seam section in which the maximum stress occurs when a bending moment is applied to the torsion profile. It has been found within the scope of the invention that by forming the width accordingly, in particular high stress peaks can be effectively absorbed by the stress relief groove. The stresses acting on the weld seam are reduced, so that the service life of the combined tie rod shaft is increased. In this case, the length of the weld seam section refers to the length of the weld seam in this section.
[0012] A person skilled in the art of motor vehicle technology can identify, based on the course of the weld between the trailing arm and the torsion profile, the weld section in which the maximum stress occurs when a bending moment is applied to the torsion profile. This weld section corresponds to the transition region of the weld from an essentially vertical course to an essentially horizontal course relative to the trailing arm.
[0013] Preferably, the stress relief groove tapers with respect to its width on the longitudinal side in the direction opposite to the corresponding weld seam. The corresponding taper of the stress relief groove ensures that stresses occurring in the connection area between the trailing arm and the torsion profile can be dissipated in a targeted manner into the central section of the torsion profile.
[0014] Preferably, the pressure relief groove transitions continuously into the shape of the torsion profile in the opposite direction to the weld seam. This has two advantages. Firstly, the pressure relief groove can be formed without cutting a groove in the torsion profile. This facilitates the manufacturing process of the combined tie rod shaft. Secondly, it has been shown within the scope of the invention that a corresponding continuous transition into the shape of the torsion profile ensures that the stresses absorbed by the pressure relief groove are further transferred into the middle section of the torsion profile. In particular, the pressure relief groove transitions into the outer surface of the torsion profile.
[0015] In another advantageous variant embodiment of the invention, the stress relief groove is arranged in the edge region of the torsion profile. This means that the stress relief groove is arranged offset laterally with respect to the central longitudinal axis of the torsion profile. Since the highest stresses occur in particular in the edge region of the transition region between the trailing arm and the torsion profile, stress peaks can be effectively absorbed by the stress relief groove arranged in the edge region.
[0016] Advantageously, the side of the stress-relief groove oriented toward the weld seam is arranged opposite a weld seam section in which the maximum stress occurs when the torsion profile is acted upon by a bending moment.
[0017] In particular, the stress-relief groove is oriented in the direction of its longitudinal extension perpendicularly to the course of the opposite weld seam section.
[0018] The pressure relief groove has in particular a depth which corresponds to 25% to 200%, preferably 30% to 60%, particularly preferably 40% to 60% of the local wall thickness of the twisted profile. This depth refers here to the maximum depth of the pressure relief groove, which is preferably arranged in the region of the pressure relief groove oriented toward the weld seam.
[0019] Preferably, the torsion profile has two pressure relief grooves in each end section of its longitudinal side in the area of the weld seam. In this variant embodiment, the stresses occurring in the transition area between the trailing arm and the torsion profile are further reduced. The pressure relief grooves are arranged in particular at the edge areas of the torsion profile.
[0020] The torsion profile preferably has a double-walled U-shaped middle section in cross section, which widens into an elliptical profile towards the end sections of the longitudinal sides. This allows the torsion profile to be connected to the corresponding longitudinal tie rods by a circumferential welding technique.
[0021] Other advantages, features, characteristics and aspects of the present invention are described below. Preferred variant designs are shown in the schematic diagrams. These drawings help to easily understand the present invention. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] In the attached picture:
[0023] Figure 1 A front view of a combined tie rod shaft according to the present invention is shown;
[0024] Figure 2 A front view showing a modular tie rod shaft according to the present invention when a vertical force is applied; and
[0025] Figure 3 A detailed perspective view of a pull-rod shaft according to the invention is shown. DETAILED DESCRIPTION
[0026] Figure 1 The invention shows a tie rod axle 1 having two trailing arms 2 connected by a torsion profile 3. In a motor vehicle, the tie rod axle 1 connects a rear wheel 10 to a vehicle body (not shown in detail). The two trailing arms 2 are oriented in the longitudinal direction X of the vehicle, while the torsion profile 3 connects the two trailing arms 2 to one another in the transverse direction Y of the vehicle. The torsion profile 3 has a torsionally flexible middle section M.
[0027] Figure 2 1 shows the twist arm shaft 1 in a state in which a vertical impact acts on each wheel 10 of the motor vehicle, which transmits a vertical force Fv to the corresponding wheel 10 in the vertical direction Z. Since the wheel 10 is coupled to the twist arm shaft 1, the wheel 10 tilts in the direction of the twist arm shaft 1. Due to the resulting bending moment, the middle section M of the torsion profile 3 is deformed. This Figure 1 and Figure 2 The combined tie arm 1 is subjected to high loads in the form of local stresses in the transition region between the rigid trailing arm 2 and the torsion profile 3 .
[0028] Figure 3 A detailed view of the transition region between a torsion profile 3 and one of the trailing arms 2 of a combined tie rod axle 1 is shown. The torsion profile 3 is joined to the trailing arm 2 in a materially bonded manner at its longitudinal end section 4 by means of a weld seam 5. The weld seam 5 follows the geometry of the components to be connected. The above-mentioned stresses in the transition region therefore act in particular at and in the weld seam 5.
[0029] The torsion profile 3 has a stress relief groove 6 in its respective longitudinal end section 4 in the region of the weld seam 5. By the arrangement of the stress relief groove 6 according to the invention, the stress acting on the weld seam 5 is absorbed by the stress relief groove 6. The load on the weld seam 5 is correspondingly reduced, which results in a longer service life of the tie rod shaft 1. The stress relief groove 6 does not increase the weight of the tie rod shaft 1 and can also be manufactured at low cost.
[0030] The middle section M of the torsion profile 3 is double-walled and U-shaped in cross section. In the direction of the longitudinal end section 4, the cross section of the torsion profile 4 widens into a circular contour. This allows the torsion profile 3 to be connected to the corresponding longitudinal tie rod 2 by welding technology.
[0031] According to the invention, the stress relief groove 6 has a longitudinal extension LR and is oriented in the direction of its longitudinal extension LR transversely to the course of the adjacent weld seam 5. Within the scope of the invention, it has been found that such an arrangement of the stress relief groove 6 is particularly advantageous for absorbing stresses acting on the weld seam 5. Furthermore, by virtue of the orientation transversely to the course of the weld seam 5, stresses are dissipated via the stress relief groove 6 into the middle section M of the torsion profile 3.
[0032] The stress-relief groove 6 has a width B on its side 7 facing the weld seam 5, which corresponds substantially to the length L of the weld seam section 8 in which the maximum stress occurs when a bending moment is applied to the torsion profile 3. It has been shown within the scope of the invention that by matching the width B to the length L of the weld seam section 8, the stresses occurring in the connection region between the trailing arm 2 and the torsion profile 3 are effectively transferred to the stress-relief groove 6, thereby avoiding stress peaks that would otherwise act on the weld seam 5.
[0033] A person skilled in the art can identify, based on the weld course between the trailing arm 3 and the torsion profile 2, at which weld section 8 the maximum stress will occur when a bending moment is applied to the torsion profile 3. In the present embodiment, the weld section 8 corresponds to the transition region of the weld 5 from the essentially vertical course V to the essentially horizontal course H with respect to the trailing arm 2. Figure 3 It can be seen that the torsional profile 3 is welded to the trailing arm 2 over the entire circumference at its longitudinal end section 4. Thus, with respect to the installation direction of the twist-arm axle 1 in the motor vehicle, the weld seam 5 transitions from a substantially vertical course V to a substantially horizontal course H.
[0034] The stress relief groove 6 tapers in terms of its width B on the longitudinal side in the direction opposite to the corresponding weld seam 5 . By a corresponding design of the stress relief groove 6 , the stresses absorbed by the stress relief groove 6 are further transferred in the direction of the middle section M of the torsion profile 3 .
[0035] The pressure relief groove 6 transitions continuously into the shape of the twisted profile 3 in the direction opposite to the weld seam 5. This has the advantage that no undercut is required for forming the pressure relief groove 6, which facilitates the manufacturing process of the twisted profile 3. On the other hand, the continuous transition of the pressure relief groove 6 to the shape of the twisted profile 3 ensures that the stress absorbed by the pressure relief groove 6 is further transferred to the middle section M of the twisted profile 3.
[0036] The pressure relief groove 6 has a depth which corresponds to 25% to 200% of the local wall thickness of the torsion profile 3. This depth is in particular the maximum depth of the pressure relief groove 6, which is provided in the region 11 of the pressure relief groove 6 oriented toward the weld seam 5.
[0037] The pressure relief groove 6 is arranged in the edge region 9 of the torsion profile 3. This means that the pressure relief groove 6 is arranged offset in the lateral direction relative to the central longitudinal axis A of the torsion profile 3. Since corresponding stress peaks occur when a bending moment is applied to the torsion profile 3, in particular in the edge region of the transition region between the trailing arm 2 and the torsion profile 3, the stresses can be advantageously absorbed by the pressure relief groove 6 arranged in the edge region 9 of the torsion profile 3.
[0038] The side surface 7 of the stress-relief groove oriented toward the weld seam 5 is arranged opposite the weld seam section 8. This arrangement has proven to be particularly advantageous for absorbing the corresponding stresses.
[0039] The torsion profile 3 can also have two pressure relief grooves 6 in each of its longitudinal end sections 4 in the region of the weld seam 5. This is not shown in the drawings. By forming two pressure relief grooves 6 in each case, stresses occurring in the transition region between the trailing arm 2 and the torsion profile 3 can be absorbed particularly advantageously.
[0040] List of reference numerals:
[0041] 1 Combined tie rod shaft
[0042] 2 longitudinal tie rods
[0043] 3Twisted profiles
[0044] 4 End section of the longitudinal side
[0045] 5. Welding Seam
[0046] 6 Pressure relief groove
[0047] 7 Side of the pressure relief groove
[0048] 8 Welding Section
[0049] 9. Marginal Area
[0050] 10 wheels
[0051] 11 Area oriented toward the weld
[0052] ACentral longitudinal axis
[0053] B Width
[0054] Fv force
[0055] H horizontal extension
[0056] L length
[0057] LR longitudinal extension
[0058] M middle section
[0059] V vertical extension
Claims
1. A combined tie rod shaft (1) for a motor vehicle, the combined tie rod shaft comprising two longitudinal arms (2) connected by a torsion profile (3), the torsion profile (3) being joined to the longitudinal arms (2) at its longitudinal end sections (4) by means of a weld seam (5) in a materially bonded manner, each end section (4) having a pressure relief groove (6) in the region of the weld seam (5), the pressure relief groove (6) having a longitudinal extension (LR) and being oriented in the direction of its longitudinal extension (LR) transversely to the course of the weld seam (5), characterized in that The pressure relief groove (6) has a width (B) on its side (7) oriented toward the weld seam (5), which width substantially corresponds to the length (L) of a weld seam section (8) in which maximum stress is generated when a bending moment is applied to the torsion profile (3), wherein the weld seam section (8) in which the maximum stress is generated when a bending moment is applied to the torsion profile (3) corresponds to a transition region of the weld seam (5) from a substantially vertical course (V) to a substantially horizontal course (H) relative to the trailing arm (2).
2. The combined tie rod shaft (1) according to claim 1, characterized in that: The stress-relief groove (6) tapers with respect to its width (B) on the longitudinal side in the direction opposite to the corresponding weld seam (5).
3. A combined tie rod shaft (1) according to any one of the preceding claims, characterized in that The pressure relief groove (6) transitions continuously into the shape of the torsion profile (3) in the direction opposite to the weld seam (5).
4. A combined tie rod shaft (1) according to any one of the preceding claims, characterized in that The pressure relief groove (6) is arranged in an edge region (9) of the torsion profile (3).
5. A combined tie rod shaft (1) according to any one of the preceding claims, characterized in that The side surface (7) of the stress-relief groove (6) oriented toward the weld seam (5) is arranged opposite the weld seam section (8), in which the maximum stress is generated when a bending moment is applied to the torsion profile (3).
6. A combined tie rod shaft (1) according to any one of the preceding claims, characterized in that The torsion profile (3) has two stress-relief grooves (6) in each of its longitudinal end sections (4) in the region of the weld seam (5).