Method of manufacturing a vehicle damper

Abstract

The present disclosure provides a method of manufacturing a damper for a vehicle. The method includes forming a groove on an outer surface of a first component in a first annular region. The first component is tubular. The method also includes inducing compressive residual stresses in a second annular region. The second annular region is at least partially aligned with the first annular region along a longitudinal axis of the first component. The method further includes coupling a second component to the first component. Surfaces of the first and second components directly engage one another at an interface. The second component is axially aligned with and radially surrounds at least a portion of the first annular region. In some configurations, forming the groove and inducing the compressive residual stresses are performed simultaneously, such as by low plasticity polishing.

Description

Technical Field

[0001] This disclosure relates to a method for manufacturing vehicle dampers. Background Technology

[0002] This section provides background information relating to this disclosure, which is not necessarily prior art.

[0003] A suspension system is designed to filter or isolate the vehicle's body (sprung parts) from the wheels and axles (unsprung parts) when the vehicle is traveling on uneven surfaces, and to control the movement of the body and wheels. In addition, the suspension system is used to maintain an average vehicle posture to promote improved vehicle stability during handling. Suspension systems can include passive suspension systems, semi-active suspension systems, and fully active suspension systems. A suspension system includes dampers with components such as pressure tubes and steering knuckles or supports, which are in direct contact with each other and are prone to relative movement during vehicle operation. Summary of the Invention

[0004] This section provides the general inventive summary of this disclosure, but is not a complete disclosure of its full scope or all its features.

[0005] This disclosure provides a method of manufacturing a damper for a vehicle. The method includes forming a groove on the outer surface of a first component in a first annular region. The first component is tubular. The method further includes inducing compressive residual stress in a second annular region. The second annular region is at least partially aligned with the first annular region along the longitudinal axis of the first component. The method further includes attaching a second component to the first component. The surfaces of the first and second components are directly engaged with each other at an interface. The second component is axially aligned with at least a portion of the first annular region and radially surrounds at least a portion of the first annular region.

[0006] In some configurations, at least a portion of the second annular region is at least partially axially aligned with the interface.

[0007] In some constructions, the formation of grooves and the induction of compressive residual stress occur simultaneously.

[0008] In some configurations, the first component is a pressure pipe and the second component is either a mounting bracket or a steering knuckle.

[0009] In some constructions, compressive residual stresses are caused by performing low-plasticity polishing.

[0010] In some configurations, low-plasticity polishing is performed at feed rates ranging from 0.05 mm / rev to 0.2 mm / rev.

[0011] In some constructions, low-plasticity polishing is performed at polishing forces ranging from 2,000 N to 4,000 N.

[0012] In some configurations, the method also includes determining the axial position of the first annular region based on the location of the expected maximum fatigue damage before forming the groove.

[0013] In some configurations, determining the axial position of the first annular region involves performing a finite element analysis on the assembly comprising the first and second components.

[0014] In some configurations, the axial range of the first region is 1 mm to 15 mm.

[0015] In some configurations, the groove has a depth ranging from 0.1 mm to half the thickness of the first component.

[0016] In some constructions, the groove has a radius ranging from 1 mm to 4 mm.

[0017] In some configurations, the groove includes an edge fillet with a radius ranging from 0.3 mm to 0.7 mm.

[0018] In some configurations, the second annular region has a depth greater than or equal to 0.5 mm.

[0019] In some configurations, the depth is equal to the thickness of the first component at the root of the groove.

[0020] In some constructions, the first component comprises a material having a yield strength. Compressive residual stress includes axial compressive residual stress. Axial compressive residual stress has a value greater than or equal to 50% of the yield strength.

[0021] In some constructions, the axial compressive residual stress has a value greater than or equal to 60% of the yield strength.

[0022] In some constructions, compressive residual stress includes axial compressive residual stress. Axial compressive residual stress has a value in the range of 300 MPa to 400 MPa.

[0023] In some constructions, compressive residual stress includes radial compressive residual stress. The first component is formed of a material with a yield strength. The radial compressive residual stress has a value greater than or equal to 5% of the yield strength.

[0024] In some configurations, connecting the second component to the first component includes press-fitting the first component into the second component or clamping the second component to the first component.

[0025] Further applicable fields will become apparent from the description provided herein. The descriptions and specific examples in this invention are for illustrative purposes only and are not intended to limit the scope of this disclosure. Attached Figure Description

[0026] The accompanying drawings described herein are for illustrative purposes only for the selected embodiments and not for all possible specific implementations, and are not intended to limit the scope of this disclosure.

[0027] Figure 1 This is a schematic diagram of a vehicle including the suspension system according to this disclosure;

[0028] Figure 2 Based on this disclosure Figure 1 A perspective view of the corner components of the suspension system;

[0029] Figure 3 Therefore Figure 2 The line 3-3 was cut off Figure 2 A partial sectional view of the corner component;

[0030] Figure 4 This is a perspective view of a corner assembly according to another embodiment of this disclosure;

[0031] Figure 5 Therefore Figure 4 The line 7-7 was cut Figure 4 A partial sectional view of the corner component;

[0032] Figure 6 This is a partial cross-sectional view of a damper according to another embodiment of this disclosure;

[0033] Figure 7 yes Figure 6 A partial cross-sectional view of the first component of the damper, which defines a groove;

[0034] Figure 8 This is a flowchart illustrating a method for manufacturing a damper assembly according to the principles of this disclosure; and

[0035] Figure 9 It is a graph depicting the damage parameters of both the ungrooved and grooved tubes.

[0036] In several views throughout the accompanying drawings, the corresponding reference numerals indicate the corresponding parts. Detailed Implementation

[0037] Exemplary embodiments will now be described in more detail with reference to the accompanying drawings.

[0038] refer to Figure 1A vehicle 10 having a suspension system according to the present disclosure is provided. The vehicle 10 includes a rear suspension 12, a front suspension 14, and a body 16. The rear suspension 12 has a laterally extending rear axle assembly (not shown) adapted to operably support the rear wheels 18 of the vehicle. The rear axle assembly is operably connected to the body 16 via a pair of corner assemblies 20, each corner assembly including a pair of shock absorbers 22 and a pair of coil springs 24. Similarly, the front suspension 14 includes a laterally extending front axle assembly (not shown) to operably support the front wheels 26 of the vehicle 10. The front axle assembly is operably connected to the body 16 via a second corner assembly 28 including a pair of shock absorbers 30 and a pair of shaped coil springs 32. The shock absorbers 22, 30 are adapted to suppress relative movement between the unsprung portions of the vehicle 10 (i.e., the front suspension 12 and rear suspension 14, respectively) and the oversprung portions (i.e., the body 16).

[0039] Although vehicle 10 has been described as a passenger vehicle with a front axle assembly and a rear axle assembly, shock absorbers 22 and 30 can be used in other types of vehicles and / or other types of applications (such as vehicles including independent front suspension systems and / or independent rear suspension systems). Furthermore, the term "shock absorber" as used herein generally refers to a damper and will therefore include struts. Additionally, although the front suspension 14 is shown as having a pair of struts or shock absorbers 30, it is also within the scope of the invention to include a pair of struts or shock absorbers 30 in the rear suspension 12 if desired. Figure 1 As shown, the shock absorber 22 is separate from the spring 24. In this configuration, an adjustable spring seat is positioned between the unsprung portion and the unsprung portion of the vehicle. Alternatively, the shock absorber 22 and spring 24 can be replaced by a corner assembly 28.

[0040] Now for reference Figure 2 The front corner assembly 28 of vehicle 10 is shown in more detail. The corner assembly 28 includes a shock absorber tower 34 made of a metal plate. The corner assembly also includes a damper or strut assembly 36. The strut assembly 36 may include a shock absorber 30, a disc spring 32, a top-mounted assembly 38, and a steering knuckle 40 as part of a wheel assembly. The shock absorber 30 includes a pressure tube 42 for housing a piston assembly and piston rod. A dust cover 44 protects an elastomeric shock absorber (not shown). The strut assembly 36 can be attached to vehicle 10 using the shock absorber tower 34. Figure 1 (As shown in the diagram). The coil spring 32 is disposed between the upper spring seat 46 and the lower spring seat assembly 48 to isolate the vehicle body 16 from the front suspension 14.

[0041] refer to Figure 3 The pressure pipe 42 is pressure-fitted into the steering knuckle 40. Therefore, the inner surface 50 of the steering knuckle 40 is in direct contact with the outer surface 52 of the pressure pipe 42. As a result, in vehicle 10 ( Figure 1During operation (as shown in the diagram), the steering knuckle 40 and pressure pipe 42 can move relative to each other, causing fatigue crack initiation and propagation, and resulting in a decrease in fatigue strength at the annular interface 54 between the steering knuckle 40 and pressure pipe 42. Therefore, as will be shown in the diagram... Figures 6 to 7 As described in more detail in the discussion, the wall 56 of the pressure tube 42 includes compressive residual stress, and the outer surface 52 defines annular grooves 58 to synergistically reduce fatigue crack initiation and propagation.

[0042] refer to Figure 4 This disclosure provides a portion of another corner assembly 70 according to the present disclosure. The corner assembly 70 includes a pressure tube 72, a mounting bracket or foot bracket 74, a base or end cap 76, and a spring seat 78. The mounting bracket 74 includes an outer bracket 80 and an inner bracket 82. The mounting bracket 74 can be clamped or pressure-fitted to the pressure tube 72 for attaching the corner assembly to a vehicle wheel. The corner assembly 70 may also include additional components, such as those described above. Figure 3 The additional components shown.

[0043] refer to Figure 5 The outer surface 84 of the pressure tube 72 is in direct contact with the inner surface 86 of the mounting bracket 74. As will be explained below in the appendix... Figures 6 to 7 As described in more detail in the discussion, the wall 88 of the pressure tube 72 includes compressive residual stress, and the outer surface 84 of the pressure tube 72 defines an annular groove 90 to synergistically reduce fatigue crack initiation and propagation.

[0044] refer to Figure 6 This provides a portion of a damper assembly 100 according to the present disclosure. The damper assembly 100 includes a first component 102 and a second component 104 extending along a longitudinal axis 103. The second component 104 radially surrounds at least a portion of the first component 104. The second component 104 can be pressure-fitted or clamped to the first component 102 such that the outer surface 106 of the first component 102 directly engages the inner surface 108 of the second component 104.

[0045] In at least one exemplary embodiment, the first component 102 is a tubular component, such as a pressure tube (see example...). Figures 2 to 3 Pressure tube 42 or Figures 4 to 5 (Pressure pipe 72). The second component 104 can be configured to connect the damper assembly 100 to the vehicle. In at least some exemplary embodiments, the second component 104 includes a steering knuckle (see, for example...). Figures 2 to 3 Steering knuckle 40) or mounting bracket or foot bracket (see example) Figures 4 to 5 (74) foot support.

[0046] The outer surface 106 of the first component 102 may define a groove 110 in the first region 120. The groove 110 may be an annular groove, and the first region 120 may be a first annular region. The second component 104 radially surrounds at least a portion of the first region 120. The inner surface 108 of the second component 104 is spaced apart from the outer surface 106 at an axial position of the groove 110.

[0047] The presence of the groove 110 can increase the fatigue life of the damper assembly 100. For example, the groove 110 reduces the contact between the outer surface 106 of the first component 102 and the inner surface 108 of the second component 104 at the location of the highest expected bending stress. Therefore, the groove 110 is adapted to relieve stress at the interface 92 between the first component 102 and the second component 104. Additionally, by positioning the groove 110 at the distal end of the second component 104, the contact between the first component 102 and the second component 104 is reduced, and the groove 110 changes the fatigue crack initiation and propagation state of the interface 92 from a mixed lubrication state to an overall sliding state, which generally increases the fatigue life of the interface 92.

[0048] The first region 120 can extend together with the groove 110. (See reference) Figure 7 The groove 110 may be defined by an axial range or length 140, a first depth 142, and a first or groove radius 144. In at least some exemplary embodiments, the groove 110 may define an edge fillet 146. Each of the edge fillets 146 may define a second or edge fillet radius 148.

[0049] In at least one exemplary embodiment, the axial range 140 may be greater than or equal to 1 mm (e.g., greater than or equal to 2 mm, greater than or equal to 3 mm, greater than or equal to 4 mm, greater than or equal to 5 mm, greater than or equal to 6 mm, greater than or equal to 7 mm, greater than or equal to 8 mm, greater than or equal to 9 mm, greater than or equal to 10 mm, greater than or equal to 11 mm, greater than or equal to 12 mm, greater than or equal to 13 mm, or greater than or equal to 14 mm). The axial range 140 may be less than or equal to 15 mm (e.g., less than or equal to 14 mm, less than or equal to 13 mm, less than or equal to 12 mm, less than or equal to 11 mm, less than or equal to 10 mm, less than or equal to 9 mm, less than or equal to 8 mm, less than or equal to 7 mm, less than or equal to 6 mm, less than or equal to 5 mm, less than or equal to 4 mm, less than or equal to 3 mm, or less than or equal to 2 mm).

[0050] The first depth 142 may be less than half the thickness 150 of the first component 102. In at least one exemplary embodiment, the first depth 142 may be greater than or equal to 0.1 mm (e.g., greater than or equal to 0.15 mm, greater than or equal to 0.2 mm, greater than or equal to 0.25 mm, greater than or equal to 0.3 mm, or greater than or equal to 0.35 mm). The first depth 142 may be less than 0.4 mm (e.g., less than or equal to 0.35 mm, less than or equal to 0.3 mm, less than or equal to 0.25 mm, less than or equal to 0.2 mm, or less than or equal to 0.15 mm).

[0051] In at least one exemplary embodiment, the first radius 144 may be greater than or equal to 1 mm (e.g., greater than or equal to 1.5 mm, greater than or equal to 2 mm, greater than or equal to 2.5 mm, greater than or equal to 3 mm, or greater than or equal to 3.5 mm). The first radius 144 may be less than or equal to 4 mm (e.g., less than or equal to 3.5 mm, less than or equal to 3 mm, less than or equal to 2.5 mm, less than or equal to 2 mm, or less than or equal to 1.5 mm).

[0052] In at least one exemplary embodiment, the second radius 148 may be greater than or equal to 0.3 mm (e.g., greater than or equal to 0.35 mm, greater than or equal to 0.4 mm, greater than or equal to 0.45 mm, greater than or equal to 0.5 mm, greater than or equal to 0.55 mm, greater than or equal to 0.6 mm, or greater than or equal to 0.65 mm). The second radius 148 may be less than or equal to 0.7 mm (e.g., less than or equal to 0.65 mm, less than or equal to 0.6 mm, less than or equal to 0.55 mm, less than or equal to 0.5 mm, less than or equal to 0.45 mm, less than or equal to 0.4 mm, less than or equal to 0.35 mm, less than or equal to 0.3 mm, or less than or equal to 0.25 mm).

[0053] Back Figure 6 The wall 160 of the first component 102 can define compressive residual stress in a second region 162, which can be a second annular region. The second region 162 axially overlaps with the first region 120. That is, at least a portion of the first region 120 and at least a portion of the second region 162 are located at a common axial position. The first region 120 is radially outside at least a portion of the second region 162. Compared to a damper assembly that only includes a groove, the increased compressive residual stress in the wall 106 causes a shift in the Woehler curve of the first component 102, resulting in a further improvement in fatigue life. Importantly, the second annular region 162 extends axially beyond the groove 110 into the direct contact region 163 between the first component 102 and the second component 104.

[0054] The second annular region 160 may define a second depth 164. The second depth 164 may be greater than or equal to 0.5 mm (e.g., greater than or equal to 0.55 mm, greater than or equal to 0.6 mm, greater than or equal to 0.65 mm, greater than or equal to 0.7 mm, greater than or equal to 0.75 mm, or greater than or equal to 0.8 mm). In at least one exemplary embodiment, the second depth 164 is equal to the tube thickness 166 at the root 168 of the groove 110.

[0055] The first component 102 is formed of a material having a yield strength. The axial compressive residual stress in the second region 162 is measured at 0° to the longitudinal axis 103 (i.e., aligned with the longitudinal axis). The axial compressive residual stress in the second region 162 may be greater than or equal to 50% of the material's yield strength (e.g., greater than or equal to 55%, 60%, or 65%). The axial compressive residual stress in the second region may be less than or equal to 70% of the yield strength (e.g., less than or equal to 65%, 60%, or 55%).

[0056] In at least one exemplary embodiment, the axial compressive residual stress is greater than or equal to 300 MPa (e.g., greater than or equal to 310 MPa, greater than or equal to 320 MPa, greater than or equal to 330 MPa, greater than or equal to 340 MPa, greater than or equal to 350 MPa, greater than or equal to 360 MPa, greater than or equal to 370 MPa, greater than or equal to 380 MPa, or greater than or equal to 390 MPa). The axial compressive residual stress may be less than or equal to 400 MPa (e.g., less than or equal to 390 MPa, less than or equal to 380 MPa, less than or equal to 370 MPa, or less than or equal to 360 MPa).

[0057] The radial compressive residual stress is measured at a 90° angle to the longitudinal axis 103. The radial compressive residual stress in the second region 162 may be greater than or equal to 5% of the material's yield strength (e.g., greater than or equal to 10%, 15%, 20%, or 25% of the yield strength). The radial compressive residual stress in the second region may be less than or equal to 30% of the yield strength (e.g., less than or equal to 25%, 20%, 15%, or 10%).

[0058] In at least one exemplary embodiment, the radial compressive residual stress is greater than or equal to 50 MPa (e.g., greater than or equal to 75 MPa, greater than or equal to 100 MPa, greater than or equal to 125 MPa, or greater than or equal to 150 MPa). The radial compressive residual stress may be less than or equal to 200 MPa (e.g., less than or equal to 175 MPa, less than or equal to 150 MPa, less than or equal to 100 MPa, less than or equal to 75 MPa, or less than or equal to 50 MPa).

[0059] refer to Figure 8 A flowchart depicting a method for manufacturing a damper according to the principles of this disclosure is provided. The method generally includes: at 200, providing a first component and a second component; at 204, determining the axial position, axial extent, and / or depth of a first annular region of the first component; at 208, forming a groove in the first annular region; at 212, inducing axial compressive residual stress in a second annular region of the first component; and at 216, attaching the second component to the first component. Each of these steps is described in more detail below.

[0060] At point 200, the method may include a first component and a second component providing a damper. The first component may be a tubular component. As discussed above, the first component may be a pressure tube, and the second component may be a steering knuckle, mounting bracket, or foot bracket. For example, the first component may be connected to... Figures 2 to 3 Pressure tube 42 or Figures 4 to 5 The pressure tube 72 is the same as or similar to the pressure tube, and the second component can be with Figures 2 to 3 Steering knuckle 40 or Figures 4 to 5 The mounting bracket 74 is the same as or similar to the mounting bracket 74.

[0061] At 204, the method may include determining the axial location, axial extent, and / or depth of a first annular region of the first component. The first annular region corresponds to the region with the highest expected fatigue crack initiation and propagation. For example, the axial location, axial extent, and / or depth of the first annular region may correspond to a region where the expected stress exceeds a predetermined value. In at least one exemplary embodiment, determining the axial location, axial extent, and / or depth of the first annular region may include performing a finite element analysis (FEA) on the assembly including the first component and the second component.

[0062] At 208, the method includes forming a groove in a first annular region on the outer surface of the first component. Forming the groove 208 may include removing and / or moving material. In at least some exemplary embodiments, forming the groove at 208 by moving material may include low-plasticity polishing, curling, local indentation (e.g., using a solid cylindrical tool), and / or any other suitable method. In at least one exemplary embodiment, forming the groove at 208 by removing material may include rotating the first component on a lathe or any other suitable process.

[0063] At 212, the method includes inducing compressive residual stress in the second region. The compressive residual stress may include axial compressive residual stress. The compressive residual stress may also include radial compressive residual stress. Inducing compressive residual stress at 212 may include low-plasticity polishing, shot peening (e.g., laser shot peening, shot peening), curling, local indentation (e.g., using a solid cylindrical tool), or any other suitable method.

[0064] In at least one exemplary embodiment, forming the groove at 208 and inducing compressive axial residual stress at 212 are performed simultaneously by the same operation, such as when the groove is formed by a mechanical process. For example, a low-plasticity polishing process can be performed to simultaneously form the groove and induce compressive residual stress. In at least one other exemplary embodiment, forming the groove at 208 and inducing compressive residual stress at 212 are performed in separate steps, such as when the groove is formed via a non-mechanical process.

[0065] In low-plasticity polishing processes, the magnitude of compressive residual stress can be controlled by the feed rate and / or polishing force. In at least one exemplary embodiment, the feed rate is greater than or equal to 0.05 mm axial advance per revolution (mm / rev) (e.g., greater than or equal to 0.075 mm / rev, greater than or equal to 0.1 mm / rev, greater than or equal to 0.125 mm / rev, greater than or equal to 0.15 mm / rev, or greater than or equal to 0.175 mm / rev). The feed rate can be less than or equal to 0.2 mm / rev (e.g., less than or equal to 0.175 mm / rev, less than or equal to 0.15 mm / rev, or less than or equal to 0.125 mm / rev, less than or equal to 0.125 mm / rev, or less than or equal to 0.1 mm / rev, or less than or equal to 0.075 mm / rev). In at least one exemplary embodiment, the polishing force is greater than or equal to 2,000 N (e.g., greater than or equal to 2,250 N, greater than or equal to 2,500 N, greater than or equal to 2,750 N, greater than or equal to 3,000 N, greater than or equal to 3,250 N, greater than or equal to 3,500 N, or greater than or equal to 3,750 N). The polishing force may be less than or equal to 4,000 N (e.g., less than or equal to 3,750 N, less than or equal to 3,500 N, less than or equal to 3,250 N, less than or equal to 3,000 N, less than or equal to 2,750 N, less than or equal to 2,500 N, or less than or equal to 2,250 N).

[0066] At 212, the method includes assembling a damper. Assembling the damper includes coupling a second component to a first component such that the inner surface of the second component is in direct contact with the outer surface of the first tubular component. The second component radially surrounds at least a portion (e.g., the entire first region) of a first annular region. In at least one exemplary embodiment, the second component is pressure-fitted to the first tubular component. In at least one other exemplary embodiment, the second component is clamped to the first tubular component.

[0067] Example 1 :

[0068] Five distinct grooves were formed at different axial locations on the outer surface of the tube using a low-plasticity polishing process. The tube is made of a material with a yield strength of approximately 600 MPa. The feed rate varied between 0.1 mm / rev and 0.2 mm / rev. The polishing force varied between 2,400 N and 3,500 N.

[0069] After the grooves were formed, X-ray diffraction (XRD) was used to determine the residual stress in each groove. The residual stress was measured at 0° (axial), 45°, and 90° (radial) relative to the longitudinal axis of the tube. Measurements were also taken at three different angular positions about the longitudinal axis: 0°, 120°, and 240°. Each measurement was performed at the root surface of the corresponding groove.

[0070] The results are shown in Table 1 below. The results indicate that the axial compressive residual stress is greater than approximately 50% of the tube's yield strength. More specifically, the axial compressive residual stress ranges from approximately 59% to approximately 67% of the tube's yield strength. The radial compressive stress is greater than or equal to approximately 5% of the tube's yield strength. More specifically, the radial compressive residual stress ranges from approximately 9% to approximately 28% of the tube's yield strength. The results also show that axial and radial compressive residual stresses are induced throughout the entire circumference of the tube.

[0071]

[0072] Table 1. Effect of polishing parameters on residual stress.

[0073] Example 2 :

[0074] A low-plasticity polishing process was used to form annular grooves in the outer surface of the tube. The process was performed at a feed rate of 0.1 mm / rev and a polishing force of 2,400 N. Axial and radial compressive residual stresses were measured using XRD at different depths, where 0 mm corresponds to the surface at the root of the groove. The results are shown in Table 2 below. The results indicate that for this set of polishing parameters, compressive residual stresses exist at a depth of at least approximately 0.8 mm.

[0075]

[0076] Table 2 Residual stress at different depths.

[0077] Example 3 :

[0078] A low-plasticity polishing process was used to form annular grooves in the outer surface of the tube. The process was performed at a feed rate of 0.1 mm / rev and a polishing force of 3,500 N. Axial and radial compressive residual stresses were measured using XRD at different depths, where 0 mm corresponds to the surface at the root of the groove. The results are shown in Table 3 below. The results indicate that, for this set of polishing parameters, compressive residual stresses exist at a depth of at least approximately 0.5 mm.

[0079]

[0080] Table 3 Residual stress at different depths.

[0081] Example 4 :

[0082] Prepare the first and second components. The first component comprises a steering knuckle connected to a tube without grooves or compressive residual stress. The second component comprises a steering knuckle connected to a tube with grooves and compressive residual stress. Grooves are formed via low-plasticity polishing at a feed rate of 0.1 mm / rev and a polishing force of 2,400 N. The component is subjected to cyclic loading. The results are shown in... Figure 9 middle.

[0083] Figure 9 This is a graph depicting cycle life on the x-axis and torque on the y-axis. Data points for the first component are shown at 300, and the trend line for the first component is shown at 302. Data points for the second component are shown at 304, and the trend line for the second component is shown at 306. As shown, at a constant time, the second component has a higher cycle life than the first component. Therefore, the results generally indicate that the second component, with its grooves and compressive residual stress, has higher durability than the first component, which includes the untreated tube.

[0084] Exemplary embodiments are provided so that this disclosure will become thorough and will fully communicate the scope to those skilled in the art. Numerous specific details, such as examples of particular 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 embodied in many different forms, and should not be construed as limiting the scope of this disclosure. In some exemplary embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.

[0085] The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” may also be intended to include the plural forms unless the context clearly indicates otherwise. The terms “comprises,” “comprising,” “including,” and “having” are inclusive and thus specify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. Unless there is an explicit order of execution, the method steps, processes, and operations described herein should not be construed as requiring performance in the specific order discussed or described. It should also be understood that additional or alternative steps may be employed.

[0086] When an element or layer is referred to as “on,” “joined to,” “connected to,” or “attached to” another element or layer, the element or layer may be directly on, joined to, connected to, or attached to the other element or layer, or there may be intermediate elements or layers present. Conversely, when an element is referred to as “directly on,” “directly joined to,” “directly connected to,” or “directly attached to” another element or layer, there may be no intermediate elements or layers present. Other terms used to describe relationships between elements should be interpreted in a similar manner (e.g., “between” vs. “directly between,” “adjacent” vs. “directly adjacent,” etc.). As used herein, the term “and / or” includes any and all combinations of one or more of the listed items.

[0087] Although the terms first, second, third, etc., are used herein to describe various elements, components, regions, layers, and / or segments, these elements, components, regions, layers, and / or segments should not be limited by these terms. These terms may only be used to distinguish one element, component, region, layer, or segment from another. Unless the context clearly indicates otherwise, terms such as “first,” “second,” and other numerical terms used herein do not imply sequence or order. Therefore, without departing from the teachings of the exemplary embodiments, the first element, component, region, layer, or segment discussed below may be referred to as a second element, component, region, layer, or segment.

[0088] Spatially related terms such as “inner,” “outer,” “below,” “below,” “lower,” “above,” and “upper” are used herein to describe the relationship of one element or feature to another, as shown in the figures. In addition to the orientations shown in the figures, spatially related terms may also be intended to cover different orientations of the device during use or operation. For example, if the device in the figures is flipped, then an element described as “below” or “below” other elements or features would be oriented as “above” other elements or features. Thus, the exemplary term “below” can cover both above and below orientations. The device can be oriented in other ways (rotated 90 degrees or otherwise), and the spatially related descriptors used herein are interpreted accordingly.

Claims

1. A method for manufacturing a damper for a vehicle, the method comprising: A groove is formed on the outer surface of a first component in the first annular region, the first component being tubular; Inducing compressive residual stress in the second annular region, the second annular region being at least partially aligned with the first annular region along the longitudinal axis of the first component; as well as The second component is coupled to the first component such that the surfaces of the first component and the second component directly engage with each other at the interface, the second component including a distal end that is axially aligned with and radially surrounds the groove, wherein the second component is spaced apart from the outer surface of the first component at the axial position of the groove; Connecting the second component to the first component includes pressurizing the first component into the second component or clamping the second component to the first component.

2. The method of claim 1, wherein at least a portion of the second annular region is at least partially axially aligned with the interface.

3. The method of claim 1, wherein the formation of the groove and the induction of the compressive residual stress occur simultaneously.

4. The method of claim 1, wherein the first component is a pressure tube and the second component is either a mounting bracket or a steering knuckle.

5. The method according to claim 1, further comprising: Before forming the groove, the axial position of the first annular region is determined based on the location of the expected maximum fatigue damage.

6. The method of claim 5, wherein determining the axial position of the first annular region comprises performing a finite element analysis on the assembly including the first component and the second component.

7. The method of claim 1, wherein the first component comprises a material having a yield strength, and the compressive residual stress comprises an axial compressive residual stress having a magnitude greater than or equal to 50% of the yield strength.

8. The method according to any one of the preceding claims, wherein the compressive residual stress includes radial compressive residual stress, the first component is formed of a material having a yield strength, and the radial compressive residual stress has a value greater than or equal to 5% of the yield strength.

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