Torsion axle assembly

Abstract

A torsion axle assembly for a vehicle includes a torsion beam extending laterally and having a top surface, a bottom surface, a rear surface, and a front surface. The torsion beam includes a pair of end portions laterally spaced by a pair of transition zones and an intermediate portion located between and separating the transition zones. The torsion beam also includes an opening defined by the bottom surface, formed in the intermediate portion and the transition zones, and outlined by edges having opposing edges. Each of the opposing edges includes a flange portion. Each flange portion includes at least one rounded portion.

Description

[0001] Cross-references to related applications

[0002] This PCT patent application claims the benefit of U.S. Provisional Patent Application No. 63 / 107,058, filed on October 29, 2020, entitled “Twist Axle Assembly”, the entire disclosure of which is considered to be part of the disclosure of this application and is incorporated herein by reference. Background Technology 1. Technical Field

[0004] This invention relates to a torsion axle assembly and a method for assembling the same. More specifically, this invention relates to a torsion axle assembly including a flange portion and a method for assembling the flange portion from a material transition zone.

[0005] 2. Related Technologies

[0006] This section provides background information relating to this disclosure, which is not necessarily prior art.

[0007] A torsion beam rear axle suspension assembly, also known as a torsion beam axle, is a type of automotive suspension system that includes a pair of trailing arms, each connected to a wheel of the vehicle, and a torsion beam extending laterally between the trailing arms. During vehicle operation, when one wheel moves relative to the other, such as during body roll or when one wheel encounters an obstacle, such as a pothole or obstacle in the road, the torsion beam deforms in a torsional motion. This torsional motion of the torsion beam reduces the movement, making the ride more comfortable for passengers in the vehicle.

[0008] Typically, it is desirable to provide a torsion beam having a pair of regions with relatively increased stiffness at the ends and relatively decreased stiffness in the longitudinal middle region. One method to provide a torsion beam with the decreased stiffness middle region and the increased stiffness end region is to form the torsion beam of the pipe fitting and press or otherwise deform the middle region of the fitting into a U-shape or V-shape. However, this process is difficult to achieve uniformly and may require one or more post-forming heat treatment operations, which increase the cost of the resulting torsion beam. Another method is to stamp the torsion beam into its shape and then weld supports to the longitudinal ends. In this method, the welded supports provide increased stiffness at the end portions.

[0009] Therefore, there has been a long-standing expectation to further develop the construction and operation of torsion beams so that the regions of the torsion beams possess desired material properties, such as reducing or eliminating fatigue from welding and finishing edges. Summary of the Invention

[0010] The features and technical advantages of the invention have been outlined rather broadly above to facilitate a better understanding of the following detailed description. Further features and advantages of the invention that form the subject matter of the claims will be described below. It will be understood by those skilled in the art that the disclosed concepts and specific embodiments can be readily used as the basis for modifications or the design of other embodiments for achieving the same objectives of the invention. It will also be recognized by those skilled in the art that such equivalent embodiments do not depart from the spirit and scope of the invention as set forth in the appended claims. This section provides a general overview of the disclosure and should not be construed as a complete and comprehensive enumeration of all objects, aspects, features, and advantages associated with the disclosure.

[0011] According to one aspect of this disclosure, a torsion axle assembly for a vehicle is provided. The torsion axle assembly includes a torsion beam extending in a transverse direction and having a top surface, a bottom surface, a rear surface, and a front surface. The torsion beam includes a pair of end portions transversely spaced by a pair of transition zones and an intermediate portion located between the transition zones. Openings are formed in the intermediate portion and the transition zones, the openings having an outline formed by edges having opposing edges, and each of the opposing edges including a flange portion.

[0012] Other areas of applicability will become apparent from the description provided herein. The descriptions and specific examples in this invention are intended for illustrative purposes only and are not intended to limit the scope of this disclosure. Attached Figure Description

[0013] The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of this disclosure. The inventive concept related to this disclosure will be more readily understood by referring to the following description taken in conjunction with the accompanying drawings, in which:

[0014] Figure 1A This is a top perspective view of a first exemplary embodiment of a torsion axle assembly including a torsion beam;

[0015] Figure 1B It was removed from a pair of tow arms. Figure 1A A top-view perspective of the torsion beam;

[0016] Figure 2A This is a bottom perspective view of a first exemplary embodiment of the torsion axle assembly;

[0017] Figure 2B It was removed from a pair of tow arms. Figure 2A A three-dimensional view of the bottom of the torsion beam;

[0018] Figure 3A This is a front view of a first exemplary embodiment of the torsion axle assembly;

[0019] Figure 3B It was removed from a pair of tow arms. Figure 3A Front view of a torsion beam;

[0020] Figure 4A This is a rear view of a first exemplary embodiment of the torsion axle assembly;

[0021] Figure 4B It was removed from a pair of tow arms. Figure 4A Rear view of the torsion beam;

[0022] Figure 5A This is a top view of a first exemplary embodiment of the torsion axle assembly;

[0023] Figure 5B It was removed from a pair of tow arms. Figure 5A Top view of the torsion beam;

[0024] Figure 6A This is a bottom view of a first exemplary embodiment of the torsion axle assembly;

[0025] Figure 6B It was removed from a pair of tow arms. Figure 6A A bottom view of the torsion beam;

[0026] Figure 7A This is a left-side view of a first exemplary embodiment of the torsion axle assembly;

[0027] Figure 7B It was removed from a pair of tow arms. Figure 7A Left side view of the torsion beam;

[0028] Figure 8A This is a right-side view of a first exemplary embodiment of the torsion axle assembly;

[0029] Figure 8B It was removed from a pair of tow arms. Figure 8A Right side view of the torsion beam;

[0030] Figure 9A It is a cross-section taken along the middle portion of a first exemplary embodiment of the torsion axle assembly;

[0031] Figure 9B It is a cross-section taken along the transition zone of a first exemplary embodiment of the torsion axle assembly;

[0032] Figure 10 It is a cross-section taken along the transition zone of a second exemplary embodiment of the torsion axle assembly;

[0033] Figure 11It is a cross-section taken along the transition region of a third exemplary embodiment of the torsion axle assembly; and

[0034] Figure 12 This is a flowchart of a method for forming a torsion axle assembly according to each embodiment. Detailed Implementation

[0035] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. Generally, the subject matter embodiments relate to a torsion axle assembly including a flange portion and a method of assembling the flange portion from a material transition zone. However, exemplary embodiments are provided only to make this disclosure thorough and to fully convey the scope to those skilled in the art. Numerous specific details, such as examples of specific components, apparatus, and methods, are set forth to provide a thorough understanding of embodiments of this disclosure. It will be apparent to those skilled in the art that specific details are not required, that exemplary embodiments may be implemented in many different forms, and that none should be construed as limiting the scope of this disclosure. In some exemplary embodiments, well-known processes, well-known apparatus structures, and well-known techniques have not been described in detail.

[0036] Referring to the accompanying drawings, in all these views, the same reference numerals indicate corresponding parts. Figures 1A to 9B The image generally illustrates a first exemplary embodiment of an improved torsion axle assembly 20 for a vehicle suspension system. (Refer to...) Figures 1A to 2B The torsion axle assembly 20 includes a pair of trailing arms 22 and a torsion beam 24 (also referred to as a lateral member) extending between the trailing arms 22 in a lateral direction (which corresponds to the lateral direction of the vehicle in use). The trailing arms 22 are configured to attach to the opposite wheels of the vehicle and, in use, pivot relative to each other in response to the vehicle rolling during high-speed cornering or in response to the wheels encountering an object, such as a pothole. The torsion beam 24 resists the relative rotation of the trailing arms 22 to reduce roll and improve the overall dynamic performance of the vehicle.

[0037] The torsion beam 24 extends in a first direction between opposite ends and includes a pair of opposite end portions 26 spaced apart by an intermediate portion 28 and a pair of transition zones 29. The pair of opposite transition zones 29 ( Figure 1BThe torsion beam 24 is located on the opposite side of the intermediate portion 28, thereby separating the intermediate portion 28 from the oppositely positioned end portion 26. The shape of the exemplary torsion beam 24 is generally symmetrical about the lateral midpoint MP of the torsion beam 24. The end portion 26 of the torsion beam 24 is connected to the trailing arm 22 to allow the trailing arm 22 to rotate relative to each other during vehicle operation. The trailing arm 22 can have any suitable shape or configuration. Both the torsion beam 24 and the trailing arm 22 are preferably made of metal (e.g., steel, steel alloy, aluminum, aluminum alloy, magnesium, magnesium alloy, etc.). The end portion 26, intermediate portion 28, and transition area 29 of the torsion beam 24 are defined by at least one sidewall 30, which can be formed from a single piece of molding material including a pair of opposing edges 31, 33 that are closely adjacent when forming the torsion beam 24. The sidewall 30 includes a mating surface 32 formed therein, such as a U-shaped recess, which covers a similar mating surface on the trailing arm 22 for establishing a glove-like connection with the trailing arm 22. Specifically, the trailing arm 22 slides into the mating surface 32 (e.g., the U-shaped recess) on the end portion 26, and then the two parts are joined together (e.g., by MIG welding, TIG welding, laser welding, etc.).

[0038] like Figure 3A and Figure 4A As best shown, the torsion beam 24 may include a variable width along its length to change the width of the torsion beam 24 on the front surface 34. Figure 3A and Figure 3B ) and rear surface 36 ( Figure 4A and Figure 4B The torsional stiffness between the two. For example, similar shapes are disclosed in PCT publication WO 2016-061078 A1, published April 21, 2016, and PCT publication WO 2016-133753 A1, published August 25, 2016, both of which are incorporated herein by reference in their entirety. Specifically, at least a portion of the intermediate portion 28 surrounding the midpoint MP of the torsion beam 24 has a first width W1, and a portion of each end portion 26 has a second width W2 greater than the first width W1. The torsion beam 24 gradually transitions from the smaller first width W1 of the intermediate portion 28 to the larger second width W2 of the end portions 26, such that the torsional stiffness of the torsion beam 24 gradually increases from the intermediate portion 28 to the end portions 26. The torsion beam 24 may also include a top surface 38 ( Figure 5A and Figure 5B ) and bottom surface 40 ( Figure 6A and Figure 6BThe shape is similar to that between the two. This shape is advantageous because during use, most of the torsion of the torsion beam 24 occurs in the middle section 28 with lower torsional stiffness, thereby improving the durability of the weld joint between the torsion beam 24 and the trailing arm 22 by protecting the weld joint from damage that may occur due to torsion in the end section 26.

[0039] As in the left view ( Figure 7B ) and right-side view ( Figure 8B As best shown in the diagram, the end portion 26 of the torsion beam 24 has a closed (or nearly closed) geometric profile, while the middle portion 28 and the transition zone 29 have an open and uncompressed geometric profile. Figure 2A and Figure 2B The end portion 26 may have a generally trapezoidal cross-section with rounded corners. More specifically, the sidewall 30 defines a front surface 34, a rear surface 36, a top surface 38, and a bottom surface 40. In one example arrangement, the bottom surface 40 of the intermediate portion 28 and the transition area 29 defines an open geometry. For example, the sidewall 30 is rolled up, wherein opposing edges 31, 33 lie on the bottom surface 40 and form the outline of the edge 44 defining the opening 46. Figure 9A At least one flange portion 42 extends from the bottom surface 40 to the opposite edges 31, 33. The cross-section of the region passing through the midpoint MP of the transition zone 29 can therefore be approximately U-shaped. Figure 7B , Figure 8B , Figure 9A and Figure 9B ).

[0040] like Figure 6A and Figure 6B As best illustrated in the diagram, edge 44 includes a straight segment 52 located on the middle portion 28, wherein opposing edges 31, 33 are parallel and opposite in the lateral direction. Edge 44 also includes widened segments 54 located on both sides of the straight segment 52, wherein opposing edges 31, 33 branch off from the straight segment 52 in the front-back direction and converge again in the front-back direction as edge 44 approaches end portion 26 and terminates at opposing edge ends 56. Edge ends 56 may include a rounded profile, wherein opposing edges 31, 33 converge again very close and extend parallel in the lateral direction to the end of end portion 26. Small space 58 ( Figure 9BThe torsion beam 24 may be located between opposing edges 31, 33 in the end portion 26. Alternatively, opposing edges 31, 33 may be joined at the end portion 26. The torsion beam 24 may also be provided with holes 60 or openings spaced apart from each other in the transverse direction to further reduce the torsional stiffness of the intermediate portion 28 compared to the end portion 26, and thereby further protect the welded joint between the torsion beam 24 and the trailing arm 22. The holes 60 may be located on the top surface 38.

[0041] Figure 7A This is a right-side view of the towing arm 22, and Figure 7B This is a left-side view of the tow arm 22. Each tow arm 22 includes a body attachment section 62 for connecting to the vehicle body and a wheel attachment section 64 for connecting to the vehicle's axle or hub. Figure 7B and Figure 8B As best illustrated in the diagram, it should be understood that, taking into account the vertical centerline VM, the connection of the torsion beam 24 to the right end of the right trailing arm 22 ( Figure 7B The torsion beam 24 is at a slight angle to the VM and is connected to the left end of the left trailing arm 22. Figure 8B (The angle relative to the right end is slightly equal to or opposite to that of VM.) Continue to refer to... Figure 7B and Figure 8B The flange portion 42 extends from the opposite side of the edge 44 in the transition region 29 and may also be located at least partially on the intermediate portion 28. More specifically, the flange portion 42 on the edge 31 near the front surface 34 extends from the opening 46 away from the bottom surface 40 toward the front surface 34, and the flange portion 42 on the edge 33 near the rear surface 36 extends symmetrically from the bottom surface 40 toward the rear surface 26.

[0042] exist Figure 9A and Figure 9BAdditional details of the flange portion 42 according to the first embodiment are best illustrated in the isometric cross-section of the torsion beam 24 presented in the figure. The flange portion 42 extends from a rounded corner between the side surfaces (front surface 34 and rear surface 36) and the bottom surface 40. The rounded corner is defined by a first radius R1, and the flange portion 42 extends from the rounded corner to a rounded portion 68 defining a second radius R2. The first radius R1 and the second radius R2 are positioned opposite to each other such that the rounded corner and the rounded portion 68 together form a generally S-shaped shape. The first radius R1 may be less than, equal to, or greater than the second radius R2. Similarly, the radian or degree of the rounded corner may be less than, equal to, or greater than the radian or degree of the rounded portion 68. The flange portion 42 may also include a straight segment 70 that extends from the rounded portion 68 to the opposing edges 31, 33 and forms part of a generally S-shaped shape. In some embodiments, the opposing edges 31, 33 are oriented parallel to the bottom surface 40 on the straight segment 52 and / or the widened segment 54, and a twisted portion 72 is formed on the flange portion 42, which bends until the opposing edges 31, 33 become perpendicular to the bottom surface 40 on the edge end 56.

[0043] like Figure 9A As shown, the radius R1, radius R2, the radius of the rounded corner and / or the radius of the rounded portion 68 can be within the transition area 29 and / or part of the intermediate portion 28 along the end portion 26 ( Figure 9B The direction of the flange portion 42 may increase or decrease. Furthermore, the straight section 70 of the flange portion 42 (extending from the bottom surface 40) may increase within the transition zone 29 and extend further from the bottom surface 40. For example... Figure 4B As best illustrated, the flange portion 42 bends outward from the middle portion 28 and enlarges to a apex 74 (the portion of the flange portion 42 furthest from the bottom surface 40) within the transition zone 29 as it approaches the end portion 26. After the apex 74, the flange portion 42 can then bend inward at a greater rate than it bends outward.

[0044] Now refer to Figure 10The illustration shows a second embodiment of the torsion beam 124. The second embodiment may include all features, shapes, and configurations of other embodiments that do not directly conflict with the modified structure. The torsion beam 124 of the second embodiment includes a flange portion 142 comprising a rounded portion 168 defining a radius R3, which merges with and at least partially extends to an adjacent rounded corner 144 surrounding an opening 146 defined by a pair of edges 131 (edges 33 not shown). The flange portion 142 may also include a straight segment 170 extending further from the rounded portion 168 into the opening 146. The straight segment 170 tapers toward the bottom side 140 as it extends toward the end portion 126 and may be curved in an area similar to that described with reference to the first embodiment. The flange portion 142 may also extend from at least a portion of the middle portion (not shown) of the torsion beam 124.

[0045] Now refer to Figure 11 The figure illustrates a third embodiment of the torsion beam 124. The third embodiment may include all features, shapes, and configurations of the other embodiments without directly conflicting with the modified structure. The torsion beam 224 of the third embodiment includes a flange portion 242 that includes a rounded portion 268 extending radially outward from one of a surface, such as a front surface 234 or a rear surface (not shown), to increase the width of the opening 246. The rounded portion 268 defines a radius R4 and leads to a straight segment 270 that twists until opposing edges 231 (edges 33 not shown) face each other. These edges 231 form the outline of an edge 244 that defines the opening 246 and also defines rounded corners that merge near the end portions (not shown).

[0046] Therefore, the torsional stiffness of the torsion beams 24, 124, 224 in the various embodiments described herein can gradually transition from a minimum torsional stiffness at approximately the midpoint MP to a maximum torsional stiffness at the end portion 26. In some embodiments, the torsion beams 24, 124, 224 can be configured such that the torsional stiffness changes from the minimum torsional stiffness to the maximum torsional stiffness at a constant rate. The flange portions 42, 142, 242 and the transition regions 29, 129, 229 are configured to reinforce the cross-section and improve fatigue performance on the edges 31, 33, 131, 231, which can be trimmed during the formation of the torsion beams 24, 124, 224. The intermediate portion 28 of the open section is configured to allow the torsion beams 24, 124, 224 to be torsionalally flexible in the event of a torsional event, while maintaining the bending stiffness of the torsion beams 24, 124, 224 at a high level to maintain wheel toe-in and camber stiffness. The end portions 26 of the torsion beams 24, 124, and 224 are constructed as closed-section beams allowing maximum stiffness to protect the welded joint between the mating surface 32 and the trailing arm 22 from fatigue damage. Various rounded portions defined by radii R1, R2, R3, and R4 reinforce the open cross-sections of the intermediate portions 28, 128, and 228 and the transition zones 29, 129, and 229. Regions of the flange portions 42, 142, and 242, such as straight segments 70, 170, and 270 extending from the rounded portions defined by radii R1, R2, R3, and R4, space the radii and edges 31, 33, 131, and 231 (“trimmed edges”) to protect the trimmed edges from fatigue damage. The flange portions 42, 142, and 242, including radii R1, R2, R3, and R4, may gradually disappear as one continues toward the closed or semi-closed end portions 26. Openings of 46, 146, and 246 can further save on material costs and reduce weight.

[0047] Another aspect of the invention provides a method 300 for manufacturing a torsion axle assembly for use in a vehicle suspension system. At 302, method 300 includes arranging a pair of trailing arms. At 304, method 300 continues by stamping a workpiece (e.g., a generally planar blank) into a torsion beam having a pair of end portions, a middle portion, and at least one transition portion having the features and shapes described herein. At 306, step 304 may further include forming a flange portion having the features and shapes described herein. At 308, step 304 may further include forming the torsion beam into a generally hourglass shape, wherein the middle portion has a first width, which is generally smaller than the width of the end portions. At 310, step 304 may further include forming the torsion beam in a configuration where the torsional stiffness of the torsion beam gradually increases from the middle portion to the end portions. At 312, the method continues by forming an opening between opposing edges that widen from the middle portion and converge near the end portions. At 314, the method continues to attach the end portion of the torsion beam to the trailing arm, for example via MIG welding, TIG welding, or laser welding.

[0048] It should be understood that the foregoing description of the embodiments is provided for illustrative purposes. In other words, the subject matter of this disclosure is not intended to be exhaustive or limiting. Elements or features of a particular embodiment are generally not limited to that particular embodiment, but are interchangeable where applicable and can be used in selected embodiments, even if not specifically shown or described. Elements or features of a particular embodiment can also be varied in many ways. Such variations should not be considered a departure from this disclosure, and all such modifications are intended to be included within the scope of this disclosure.

Claims

1. A torsion axle assembly for a vehicle, comprising: a torsion beam extending along a transverse direction and having a top surface, a bottom surface, a rear surface, and a front surface; the torsion beam including a pair of end portions laterally spaced apart by a pair of transition zones and an intermediate portion between the transition zones; an opening formed in the intermediate portion and the transition zones and defined by a rim having opposing edges; and wherein each of the opposing edges includes a flange portion, the flange portion includes at least one rounded portion, each of the flange portions extends from the bottom surface, each opposing edge twists from a parallel relationship to the bottom surface to a perpendicular relationship to the bottom surface, and the flange portion further curves outward from the bottom surface to a vertex.

2. The torsion axle assembly of claim 1, wherein, the flange portion bends inward toward the bottom surface from opposite directions of the vertex as the flange portion approaches the end portion.

3. The torsion axle assembly of claim 2, wherein, the flange portion curves outward at a first rate and bends inward at a second rate, wherein the first rate is less than the second rate.

4. The torsion axle assembly of claim 1, wherein, a corner between the bottom surface and the front surface is rounded, and wherein a corner between the bottom surface and the rear surface is rounded.

5. The torsion axle assembly of claim 4, wherein, the at least one rounded portion extends from the rounded corner to form an S-shape.

6. The torsion axle assembly of claim 1, wherein, the at least one rounded portion extends to a straight section extending from the bottom surface toward the top surface.

7. The torsion axle assembly of claim 6, wherein, the straight section tapers toward the bottom surface as the straight section extends in a direction of the end portion.

8. The torsion axle assembly of claim 1, wherein, the at least one rounded portion extends outward away from the front surface or the rear surface.

9. The torsion axle assembly of claim 8, wherein, the at least one rounded portion extends to a straight section extending away from the bottom surface.

10. The torsion axle assembly of claim 1, wherein, the opposing edges converge into a parallel and facing relationship at the end portion.

11. The torsion axle assembly of claim 1, wherein, the torsion beam is configured to have a torsional stiffness that gradually increases from the intermediate portion to the end portion.

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