Axle Spring Seat Attachment Assembly

Abstract

The present invention relates to a spring seat attachment assembly for an axle / suspension system having at least one leaf spring and an axle, the attachment assembly comprising a band and a spring seat. The band may include a locator structure and is secured to the axle and extends between 180 degrees and 360 degrees around a portion of the axle. The spring seat receives the leaf spring and is secured to the band.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Patent Application No. 62 / 724,675, filed on August 30, 2018. Technical Field

[0003] The present disclosure generally relates to axle / suspension systems for heavy vehicles. Specifically, the present disclosure relates to axle / suspension systems for heavy vehicles that employ axle seats for leaf springs. More specifically, the present disclosure relates to spring seat attachment assemblies for axle / suspension systems for heavy vehicles. Background Art

[0004] Axle / suspension systems for heavy vehicles are known. For convenience, reference will generally be made to heavy vehicles, it being understood that such reference includes trucks, tractor-trailers or semi-trailers, trailers, etc. The axle / suspension system typically includes a pair of laterally spaced suspension assemblies connected to a main frame of the vehicle or a subframe supported by the main frame. Such a subframe may be a non-removable or removable slider box, a slider subframe, a slider undercarriage, a sub-slider frame, or an undercarriage. For convenience, reference will be made to a frame, it being understood that such reference includes a main frame, a non-removable subframe, and a removable subframe, etc.

[0005] The suspension components of the axle / suspension system are usually mounted to the axle on the corresponding opposite ends of the axle to locate the axle or fix the position of the axle and stabilize the heavy vehicle. During operation, the road conditions encountered by the wheels of the heavy vehicle apply various forces to the axle on which the wheels are mounted. This in turn applies various forces to the suspension components connected to and supporting the heavy vehicle. In order to eliminate or minimize the harmful effects of these forces and the loads caused to the frame or other components, cargo and occupants during the operation of the heavy vehicle, the suspension components of the axle / suspension system are designed to absorb or buffer at least some of the forces.

[0006] The axle / suspension system can be a mechanical spring axle / suspension system using a mechanical suspension assembly. In some heavy vehicles, one or more mechanical spring axle / suspension systems can be used at the front and rear of the heavy vehicle. The construction of the front axle / suspension system and the rear axle / suspension system is collectively referred to as a tandem axle / suspension system. For convenience, reference should be made to the axle / suspension system, but it should be understood that the reference includes a mechanical spring axle / suspension system and a tandem axle / suspension system. Similarly, for convenience, reference should be made to the suspension assembly, but it should be understood that such reference includes a mechanical suspension assembly. The mechanical suspension assembly typically includes a pair of laterally spaced leaf spring groups or stacks connected to the axle. The leaf spring stack is typically connected to the axle by a prior art spring seat assembly, which utilizes a U-bolt connection to maintain the integrity of the spring. Each leaf spring stack is designed and constructed to carry the rated vertical load of its corresponding axle.

[0007] The prior art spring seat assembly generally includes a top block, a top axle seat and a bottom axle seat. The top block is disposed on the upper surface of the leaf spring stack. The top axle seat extends between the bottom of the leaf spring stack and an upper portion of the axle vertically aligned with the top block. The bottom axle seat is generally a curved plate disposed on a lower portion of the axle vertically aligned with the top block and the top axle seat. As is well known, the top axle seat and the bottom axle seat are rigidly connected to the axle by a line weld or a window weld, respectively, which is generally in the front and rear quadrants of the axle, adjacent to the neutral axis of the axle. Attachment in the front and rear quadrants of the axle is desirable because these areas are generally subjected to less stress than the top and bottom quadrants of the axle. Specifically, during heavy vehicle operation, the top quadrant of the axle is generally in a constant state of compression, while the bottom quadrant is in a constant state of tension. The spring seat assembly also includes a pair of U-bolts, each of which engages the top block and extends through a pair of openings formed in the bottom axle seat. Thus, when the nut is tightened onto the end of the U-bolt, the top block, leaf spring, top axle seat, axle and bottom axle seat are rigidly clamped together.

[0008] The prior art spring seat assembly has potential disadvantages, defects and limitations while fully securing the shaft to the leaf spring stack. For example, the prior art spring seat assembly generally requires the shaft to have a thicker center tube because the shaft spring seat assembly is attached to the center tube of the shaft by a line weld. Specifically, a thin-walled shaft may be more susceptible to the harmful stresses generated by the line weld, which may form a weak area on the center tube. More specifically, a line weld is a weld that starts at one point and ends at a separate point. The starting and ending points of the line weld form local areas where the shaft material properties change and weak areas that are susceptible to stress (called stress concentration). Therefore, when the prior art spring seat assembly is line welded to the center tube, the areas formed adjacent to the starting and ending points of each weld are generally more susceptible to stress than non-welded areas or other types of welded areas that lack obvious starting and ending points. This results in welded higher stress areas along the center tube of the shaft being more susceptible to potential damage from forces and loads acting on the shaft than unwelded areas. To compensate for this increased sensitivity, prior art axle / suspension systems typically increase the thickness of the center tube of the axle, which undesirably increases the weight, amount of material, and cost of manufacturing the axle / suspension system.

[0009] Additionally, prior art axle / suspension systems having axle spring seats, while operating satisfactorily using line welds or window welds located in the forward and aft quadrants of the axle, may unexpectedly experience less than optimal wear rates due to cyclical forces and loads across the axle generated by the acceleration and deceleration of heavy vehicles and exacerbated by loading conditions during operation. Summary of the invention

[0010] As a result, there is a need in the art for an axle spring seat attachment assembly that overcomes the shortcomings, deficiencies and limitations of the prior art axle spring seat assemblies. According to the present disclosure, an axle spring seat attachment assembly for a thin-walled axle does not require the use of line welds or welds in high stress areas, thereby eliminating or minimizing the effects of stress concentrations on the axle center tube and allowing the use of a relatively thin-walled axle, thereby reducing weight, reducing material count and reducing manufacturing costs of the axle / suspension system.

[0011] The summary is provided to introduce the concepts of the present disclosure. The summary is not intended to identify the key factors or essential features of the present disclosure. The summary is also not intended to limit the scope of the present disclosure.

[0012] According to one aspect of the present disclosure, a spring seat attachment assembly for use with an axle / suspension system having a leaf spring and an axle includes a mounting band and at least one spring seat. The mounting band is secured to the axle and extends between 180 and 360 degrees around a portion of the axle. The spring seat receives the leaf spring and is secured to the mounting band.

[0013] According to another aspect of the present disclosure, a spring seat attachment assembly for use with an axle / suspension system having a leaf spring and an axle includes a mounting band, a locating structure, and at least one spring seat. The mounting band has an opening and extends between 180 degrees and 360 degrees around a portion of the axle. The locating structure is fixed to the axle. The locating structure is at least partially separated from the mounting band and disposed within the opening of the mounting band. The spring seat receives the leaf spring and is fixed to the mounting band. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The following description and accompanying drawings set forth certain illustrative aspects and embodiments of the present disclosure. These represent only some of the various ways in which one or more aspects may be employed. Other features of the present invention will become apparent to those skilled in the art by reading the following description with reference to the accompanying drawings, among which:

[0015] FIG. 1 is a driver's side perspective view of a prior art axle / suspension system;

[0016] Figure 2 is a perspective view of a portion of a prior art axle / suspension system showing a pair of prior art spring seats wire welded to the axle;

[0017] Figure 3 yes Figure 2 A cross-sectional view of the shaft shown taken along line AA with components of the prior art spring seat and brake system removed;

[0018] Figure 4 is a partially phantom partial perspective view of a portion of a top mounted or overmounted mechanical spring axle / suspension system having a pair of axle spring seat attachment assemblies according to one aspect of the present invention;

[0019] Figure 5 yes Figure 4 a cross-sectional view of the shaft shown in taken along line BB with components of the shaft spring seat attachment assembly and the brake system removed;

[0020] Figure 6 yes Figure 4 a partially phantom enlarged top perspective view of a portion of the axle spring seat attachment assembly shown in , showing the axle spring seat attachment assembly without the top spring seat;

[0021] Figure 7 yes Figure 4 an enlarged top perspective view of the shaft spring seat attachment assembly shown in , with the shaft removed;

[0022] Figure 8 yes Figure 4 and Figure 7 a bottom perspective view of the shaft spring seat attachment assembly shown;

[0023] Fig. 9 is a partially phantom partial perspective view of a portion of a bottom mounted or undermount mechanical spring axle / suspension system having a pair of axle spring seat attachment assemblies according to another aspect of the present disclosure;

[0024] Fig.10 yes Fig. 9 an enlarged perspective view of the shaft-spring seat connection assembly shown with the shaft removed;

[0025] Fig.11 yes Fig. 9 and Fig.10 A partial phantom elevation view of the shaft spring seat attachment assembly is shown;

[0026] Fig.12 is a partially phantom partial perspective view of a portion of a top mounted or overmounted mechanical spring axle / suspension system having a pair of axle spring seat attachment assemblies according to yet another aspect of the present invention;

[0027] Fig.13 yes Fig.12 a partially phantom enlarged top perspective view of a portion of the axle spring seat attachment assembly shown in , showing the axle spring seat attachment assembly without the top spring seat;

[0028] Fig.14 yes Fig.12 an enlarged top perspective view of a portion of the shaft spring seat attachment assembly shown;

[0029] Fig.15 yes Fig.12 and 14 A bottom perspective view of the shaft-spring seat connection shown with the shaft removed;

[0030] Fig.16 is a partially phantom partial perspective view of a portion of a bottom mounted or undermount mechanical spring axle / suspension system having a pair of axle spring seat attachment assemblies according to yet another aspect of the present disclosure;

[0031] Fig.17 yes Fig.16 an enlarged perspective view of a mounting strap of the axle spring seat mounting assembly shown;

[0032] Fig.18 yes Fig.16 an enlarged perspective view of the shaft spring seat attachment assembly shown with the shaft removed; and

[0033] Fig.19 yes Fig.17 An enlarged perspective view of the mounting band of the shaft spring seat attachment assembly is shown showing the retainers, openings and windows having alternating continuous shapes.

[0034] Like reference numerals refer to like parts throughout. DETAILED DESCRIPTION

[0035] To better understand the axle spring seat attachment assembly of the present disclosure, a prior art axle / suspension system 10 employing a prior art spring seat assembly 52 is shown in FIG. The prior art axle / suspension system 10 utilizes a front or forward axle / suspension system 12 and a rear or rearward axle / suspension system 14, both of which are shown in a top-mounted or top-mounted configuration. Each of the front and rear axle / suspension systems 12, 14 is connected to and suspended from a vehicle frame 16, respectively.

[0036] The front axle / suspension system 12 includes a pair of mirror-imaged, laterally spaced, longitudinally extending suspension assemblies 18 connected to a front axle 20F. Similarly, the rear axle / suspension system 14 includes a pair of mirror-imaged, laterally spaced, longitudinally extending suspension assemblies 22 connected to a rear axle 20R. Since the front suspension assemblies 18 are mirror images of each other and the rear suspension assemblies 22 are mirror images of each other, only one of each suspension assembly will be described.

[0037] The front suspension assembly 18 includes a leaf spring stack 24 disposed above and connected to the front axle 20F. The leaf spring stack 24 includes a plurality of individual leaf springs 26 having a top leaf spring or top spring 26T. The top leaf spring or top spring 26T of the leaf spring stack 24 extends longitudinally between a front hanger 28 mounted on the frame 16 and suspended from the frame and a rocker or equalizer 30. A front end 32 of the top spring 26T is formed so that the front end of the top spring can rest on and engage a cam or slider (not shown) mounted in the front hanger 28. A rear end (not shown) of the top spring 26T is formed so that the rear end can rest on and engage another cam or slider (not shown) mounted in the equalizer 30. The equalizer 30 is pivotally connected to a center hanger 36 by a pin and bushing assembly 38. The center hanger 36 is mounted on and suspended from the frame 16. This configuration enables the top spring 26T and leaf spring stack 24 to float or slide at the front hanger 28 and center hanger 36, respectively, in response to certain loading conditions.

[0038] The rear suspension assembly 22 similarly includes a rear spring stack 40 connected to and disposed above the rear axle 20R. The rear spring stack 40 includes a plurality of individual leaf springs 42 having a top spring 42T. The top spring 42T of each rear spring stack 40 extends longitudinally between a rear hanger 44 suspended from the frame 16 and the balancer 30. The front end (not shown) of the top spring 42T is formed so that the front end can rest on and engage a cam or slider (not shown) mounted in the balancer 30. The balancer 30 provides a connection between the front suspension assembly 18 and the rear suspension assembly 22, respectively, and pivots to balance the load between the front axle 20F and the rear axle 20R, respectively. The rear end (not shown) of the top spring 42T is formed so that the rear end can rest on and engage another cam or slider (not shown) mounted in the rear hanger 44. Thus, the top spring 42T and rear spring stack 40 are able to float or slide at the center hanger 36 and rear hanger 44, respectively, in response to certain loading conditions.

[0039] The plurality of leaf springs 26, 42 of the leaf spring stack 24, 40 are held together by a central bolt (not shown) and attached to the shafts 20F, 20R, respectively, by spring seat assemblies 52. The central bolt extends through an opening (not shown) formed in each leaf spring 26, 42 near the longitudinal midpoint of each leaf spring to connect the leaf springs to one another.

[0040] Each spring seat assembly 52 includes a top block 54, a top axle seat or spring seat 56, and a bottom axle seat or spring seat 58. The top block 54 is disposed on the upper surface of the top spring 26T near the longitudinal midpoint of the top spring. The top spring seat 56 is located between the bottom of the leaf spring stack 24 and the top portion of the front axle 20F vertically aligned with the top block. The bottom spring seat 58 is disposed on the bottom portion of the front axle 20F vertically aligned with the top block 54 and the top spring seat 56. The spring seat assembly 52 also includes a pair of U-bolts 60, each of which engages the top block 54 and extends downwardly through a pair of openings (not shown) formed in the bottom spring seat 58. When the nut 62 is tightened onto the threaded portion of the U-bolt 60, this allows the top block 54, the leaf spring stack 24, the top spring seat 56, the axle 20F, and the bottom spring seat 58 to be tightly clamped together. Similarly, the leaf springs 42 of the rear spring stack 40 are held together by a center bolt (not shown) and clamped to the rear axle 20R by the spring seat assembly 52 and U-bolts 60 .

[0041] To control fore-aft movement of the front axle 20F, a front torque arm or radius rod 64 is pivotally connected to and extends between the front hanger 28 and the top spring seat 56 of the front axle. To control fore-aft movement of the rear axle 20R, a rear radius rod 66 is pivotally connected to and extends between the center hanger 36 and the top spring seat 56 of the rear axle.

[0042] exist Figure 2 , a portion of a prior art spring seat assembly 52 is shown, which is fixed to the shaft 20F. The shaft 20F includes a center tube 106 and a pair of shaft spindles 108 connected to the respective ends of the center tube by any suitable means (e.g., welding). A torque plate or brake spider 110 can be mounted on each shaft spindle 108. Also refer to Figure 3-4 , axis 20F also includes a horizontal neutral axis plane N, a top quadrant Q1, a rear quadrant Q2, a bottom quadrant Q3 and a front quadrant Q4.

[0043] The top spring seat 56 of the prior art generally has an inverted U-shape, which enables the top spring seat to at least partially surround the shaft 20F, 20R. Specifically, the inverted U-shape of the top spring seat 56 of the prior art is configured to facilitate seating and clamping directly on the shaft 20F, 20R. In addition, the top spring seat 56 of the prior art is generally directly attached to the shaft 20F, 20R in the front quadrant Q4 and the rear quadrant Q2 of the shaft, respectively, through a line weld LWS formed between the top spring seat and the shaft. The line weld LWS is disposed substantially along or adjacent to the neutral axis plane N in the front and rear quadrants Q4, Q2 of the shaft 20F, 20R, respectively, because the stresses received by the front and rear quadrants and the neutral axis are relatively smaller than those received by the top quadrant Q1 and the bottom quadrant Q3, respectively.

[0044] The prior art spring seat assembly 52 has potential disadvantages, drawbacks and limitations in adequately securing the shaft 20F, 20R to the leaf spring stack 24, 40. For example, the spring seat assembly 52 requires the use of a line weld LWS to connect the spring seat assembly to the shaft 20F, 20R. As a result, the start and end points of the line weld LWS may create stress concentrations and localized mechanical property changes in the center tube 106 of the shaft 20F, 20R, thereby weakening the center tube. In order to compensate for the stress concentrations, the thickness of the center tube 106 is typically increased. As a result, the weight, material volume and manufacturing cost of the shaft 20F, 20R are undesirably increased, thereby reducing the fuel efficiency of the heavy vehicle and increasing the operating cost of the heavy vehicle.

[0045] Moreover, the top spring seat 56 of the prior art may unexpectedly be subjected to increased wear due to being attached to the front quadrant Q4 and the rear quadrant Q2 of the shaft 20F, 20R, respectively. More specifically, the alternating forces applied to the shaft 20F, 20R by the acceleration and deceleration of the heavy vehicle and aggravated by the load cause a sinusoidal stress change from tension to compression, thereby causing reverse cycle fatigue in the front and rear quadrants. This reverse cycle fatigue may break the connection of the line weld LWS between the top spring seat 56 and the center tube 106, thereby potentially causing damage.

[0046] Therefore, there is a need for an axle spring seat attachment assembly for an axle / suspension system that minimizes the use of line welds, reduces stress concentrations, and provides better attachment of the spring seat to the axle. The disclosed axle spring seat attachment assembly for an axle / suspension system meets this need and enables the use of a thin-walled axle, thereby reducing weight, material volume, and cost of manufacturing the axle / suspension system.

[0047] According to one aspect of the present disclosure, Figure 4-8 A pair of axle spring seat attachment assemblies 252 are shown in FIG. The axle spring seat attachment assemblies 252 are shown incorporated into the axle / suspension system 200. The axle / suspension system 200 includes a neutral axis N' ( Figure 5 ), top quadrant Q1', rear quadrant Q2', bottom quadrant Q3' and front quadrant Q4'. The shaft 220 includes a center tube 206 and a pair of shaft spindles 208 mounted on respective ends of the center tube. A pair of torque plates or brake spiders 210 may be mounted on respective shaft spindles 208. The shaft / suspension system 200 is in a top mounted or top mounted configuration, wherein a longitudinally extending leaf spring stack 224 ( Figure 4 ) is typically disposed on or above the axle 220. However, it is contemplated that the axle spring seat attachment assembly 252 may be used with any other type and / or configuration of axle / suspension system.

[0048] Each axle spring seat attachment assembly 252 has an upper or top bracket or spring seat 256 and a bottom spring seat 258 that is rigidly secured to a mounting strap 259 ( Figure 6 ). Each mounting band 259 is at least partially disposed around the shaft 220 and in close contact with the shaft. Specifically, the mounting band 259 extends at least 180 degrees but less than 360 degrees around the center tube 206. More specifically, the mounting band 259 has an arcuate recess or inner surface 272 that is complementary to the periphery of the upper half of the center tube 206 of the shaft 220. The inner surface 272 defines a dimension D1 that, depending on the mounting method, can range from significantly less than the outer diameter of the smallest center tube 206 on which the mounting band 259 is mounted to approximately the same as the outer diameter. The mounting band 259 is oriented so that the opposite ends 257 of the mounting band (only one is shown) are located in the front quadrant Q4' and the rear quadrant Q2' of the shaft 220, respectively.

[0049] The mounting band 259 is disposed or snapped onto the shaft 220 by applying an appropriate amount of lateral force using any suitable means, such as a hydraulic press (not shown) or with the aid of a suitable tool or adapter, such as a clamping system (not shown), so that the inner surface 272 of the mounting band contacts the shaft. Specifically, an appropriate amount of force is applied to the outer surface 274 of the mounting band 259 laterally across the shaft 220 by the hydraulic press. The appropriate amount of force applied to the outer surface 274 can cause the mounting band 259 to elastically deform in the area around which it is disposed.

[0050] The fit of the inner surface 272 of the mounting band 259 to the shaft 220 goes beyond a simple force fit. While force fitting the inner surface 272 of the mounting band 259 to the shaft 220 generally produces uninterrupted contact, it also leaves discontinuous areas of gap at the interface between the outer surface of the upper portion of the shaft and the inner surface of the mounting band. As a result, gap areas at critical areas between the shaft 220 and the mounting band 259 can remain. However, an appropriate amount of force applied to the outer surface 274 provides a close contact that exceeds a force fit, a press fit, or an interference fit. Specifically, an appropriate amount of force applied to the mounting band 259 supported on the shaft 220 eliminates any significant gap between the outer surface of the upper portion of the shaft and the inner surface 272 of the mounting band. If there is no gap between the shaft and the mounting band 259, especially in critical areas between the shaft and the mounting band, such as where a weld may be formed, a close contact condition can exist without actual deformation of the shaft 220. This intimate contact provides a constant relatively low preload or compression state between the center tube 206 and the mounting band 259, which greatly limits the relative movement between the center tube and the mounting band. The intimate contact eliminates various stresses and improves reverse cycle fatigue strength, thereby preventing potential adverse effects on the integrity of the shaft 220 or the weld between the mounting band 259 and the shaft.

[0051] A window 270 is formed in the mounting band 259, generally above or near the top quadrant Q1' of the axis 220. Figure 6-8 This allows a continuous window weld CWW to be placed in the window 270 between the mounting band 259 and the center tube 206 of the shaft 220 ( Figure 6 ), to supplement the preload condition and enhance the fixation of the mounting band to the shaft. The continuous window weld CWW starts and stops at the same position within the window 270, so that it has no starting or ending point. As a result, stress concentrations in the shaft 220 caused by the different starting and ending points of the weld can be reduced and / or eliminated. The reduction in stress concentration eliminates the need for thicker or heavier walled prior art shafts and allows the use of thin-walled shafts 220. The placement of the continuous window weld CWW on the top quadrant Q1' of the shaft 220 also unexpectedly results in a stronger connection between the center tube 206 and the mounting band 259, with reduced wear compared to the prior art spring seat assembly 52 attached to the front and / or rear quadrants Q4, Q2 of the shaft 20F, 20R, respectively, by line welds or window welds. The improvement in connection is due, at least in part, to the constant compression applied to the continuous window weld CWW by the weight or load of the heavy vehicle. Specifically, during heavy vehicle operation, the top quadrant Q1' of the shaft 220 (where the continuous window weld CWW is located) is typically under constant compression. Through this constant compression on the continuous window weld CWW, reverse cycle fatigue caused by acceleration and braking of heavy vehicles, and the resulting vertical and fore-aft loads, can be reduced or eliminated.

[0052] Top spring seat 256 ( Figure 7-8 ) has an inverted generally U-shape to surround a portion of the center tube 206. The top spring seat 256 includes a pair of side walls 246, a pair of end walls 250, and a spring wall 248. The side walls 246, the end walls 250, and the spring wall 248 are formed separately and connected together as a subassembly by a suitable means such as welding. Alternatively, the side walls 246, the end walls 250, and the spring wall 248 can be integrally formed as a single piece by any suitable method such as casting or forging. The spring wall 248 is generally planar and has a generally rectangular shape. The spring wall 248 has a pair of recesses 249 formed in each side. The spring wall 248 is formed with an opening 234 to receive a pin or a center bolt (not shown) that can extend through the leaf spring stack 224.

[0053] The pair of side walls 246 extend longitudinally in parallel and are spaced apart from each other by a width W1 ( Figure 7 and 8 ). The side wall 246 also extends substantially perpendicularly relative to the spring wall 248. The side wall 246 includes a pair of protrusions or projections 247 extending toward the spring wall 248. The projections 247 are respectively received in a corresponding one of a pair of recesses 249 of the spring wall 248 to retain the side wall 246 on the spring wall. Each side wall 246 may also include a bracket portion 237 extending forward or rearward. The bracket portion 237 has a pair of laterally aligned openings 239 for receiving fasteners (not shown) to connect to the radius rod (not shown). Each side wall 246 has an inverted generally U-shape so that each side wall complementarily receives the center tube 206 in a press fit or interference fit manner. It is contemplated that the side wall 246 of the present disclosure may also receive the center tube 206 in a clearance fit manner.

[0054] The end wall 250 is disposed between the side walls 246 and is perpendicular to the side walls 246. The end wall 250 may extend inwardly toward the center tube 206 at an angle from the longitudinally opposite ends of the spring wall 248, thereby forming an opposite slope. Alternatively, the end wall 250 may extend perpendicularly relative to the longitudinally opposite ends of the spring wall 248. The end wall 250 generally extends such that the bottom end 255 ( Figure 7 ) is recessed relative to the bottom end 245 of the side wall 246. Alternatively, the end wall 250 can be extended so that the bottom end 255 of the end wall is coplanar with the bottom end 245 of the side wall 246 or extends beyond the bottom end 245 of the side wall 246. Each end wall 250 includes a protrusion or projection 251 extending toward the spring wall 248. The projection 251 engages and extends into a corresponding groove 253 formed in the spring wall 248 to secure the end wall 250 to the spring wall.

[0055] According to an important aspect of the present disclosure, the top spring seat 256 is indirectly attached to the shaft 220. Specifically, once the mounting band has been attached to the center tube 206, the top spring seat 256 is disposed above the mounting band 259 and is only secured to the mounting band 259. The top spring seat 256 can be positioned above the mounting band 259 so that the opening 234 in the spring wall 248 can be at least substantially adjacent to or aligned with the window 270 of the mounting band. The width W2 ( Figure 8 ) is less than the width W1 extending between the side walls 246 of the top spring seat 256. The top spring seat 256 can then be disposed around a portion of the shaft 220 such that a majority of the mounting band 259 is located between the side walls 246. It is also contemplated that a portion of the mounting band 259 adjacent each of the opposing ends 257 can extend circumferentially around the shaft beyond the bottom end 245 of the side walls 246 and may not be disposed between the side walls, such as Figure 7 As shown. The side wall 246 can receive the edge 276 of the mounting band 259 in a clearance manner. Alternatively, the side wall 246 can receive the edge 276 in a press fit or interference fit manner. The end wall 250 forms an interface with the outer surface 274 of the mounting band 259. A line weld LWS is formed along the interface between the outer surface 274 of the mounting band 259 and the end wall 250 of the top spring seat 256 to fix the top spring seat to the mounting band. After cooling, the line weld LWS will generate tension to maintain close contact between the mounting band 259 and the shaft 220.

[0056] The bottom spring seat 258 is similar in structure and arrangement to the top spring seat 256. Specifically, the bottom spring seat 258 is generally U-shaped to surround a portion of the shaft 220. The bottom spring seat 258 includes a bottom plate 268, a pair of side walls 262, and a pair of inclined end walls 280. The side walls 262, the end walls 280, and the bottom plate 268 are formed separately and connected into a subassembly by any suitable means such as welding. Alternatively, the side walls 262, the end walls 280, and the bottom plate 268 can be integrally formed as a single piece by any suitable method such as casting or forging. The bottom plate 268 is generally planar and generally rectangular. The bottom plate 268 includes one or more but preferably four integrally formed protrusions 266 coplanar with the bottom plate. Each protrusion 266 is adjacent to a respective corner of the bottom plate 268 and extends outwardly from the respective corner of the bottom plate 268. The bottom plate 268 may be formed with an opening 269 for receiving a pin or dowel (not shown) extending through the leaf spring stack 224 .

[0057] The side walls 262 extend longitudinally in parallel and are spaced apart from each other by a width W3 ( Figure 6-8). The sidewalls 262 also extend perpendicularly relative to the bottom plate 268 adjacent to the protrusions 266, such that the protrusions extend away from the sidewalls 262 in opposite directions perpendicular to the sidewalls 262. Each sidewall 262 has a generally U-shape of the bottom spring seat 258, such that each sidewall complementarily receives the center tube 206 in a press fit or interference fit. It is also contemplated that the sidewalls 262 may receive the center tube 206 in a clearance fit.

[0058] Each protrusion 266 of the bottom plate 268 is formed with a corresponding opening 267. Each opening 267 receives the end of one of a pair of U-bolts (not shown), which, as is known, form the main connection between the leaf spring stack 224 and the center tube 206. A series of guide walls 290 can be integrally formed with the protrusions 266 and extend perpendicularly relative to the protrusions 266. The guide walls 290 are adjacent and can abut or connect to the sidewalls 262. The guide walls 290 at least partially surround the threaded portion and / or shank portion of the U-bolt. During operation of a heavy vehicle, the U-bolt can engage the guide walls 290. The guide walls 290 provide a structure over which lateral and fore-and-aft forces acting on the U-bolts can be distributed. As a result, the protrusions 266 of the bottom plate 268 are less likely to be deformed due to the forces acting on the U-bolts.

[0059] The end walls 280 of the bottom spring seat 258 extend angularly from the longitudinally opposite ends of the bottom plate 268 toward the center tube 206, thereby forming opposite slopes. Each end wall 280 is perpendicular to the side walls 262 and is disposed between the side walls 262. The end walls 280 generally extend so that the top end portion 281 of the end wall is recessed relative to the top end portion 263 of the side wall 262. Alternatively, the end wall 280 may extend so that the top end portion 281 of the end wall is coplanar with the top end portion 263 of the side wall 262 or extends beyond the top end portion 263 of the side wall 262.

[0060] According to another important aspect of the present disclosure, the bottom spring seat 258 is indirectly attached to the shaft 220. Specifically, the bottom spring seat 258 is at least partially disposed above the mounting band 259 and is fixed only to the mounting band 259. Specifically, the width W2 of the mounting band 259 is equal to or less than the width W3 extending between the side walls 262. The bottom spring seat 258 can be disposed around the center tube 206 of the shaft 220 so that the portion of the mounting band 259 adjacent to each of the opposing ends 257 is disposed between the side walls 262. As a result, the side walls 262 overlap the circumferential length (not shown) of the edge 276 of the mounting band 259. The mounting band 259 may include a pair of lateral protrusions or projections 261 ( Figure 6-8). Once the bottom spring seat 258 is placed around the mounting band 259, the protrusion 261 engages a corresponding notch 264 formed in the top end 263 of the side wall 262. Thus, the protrusion 261 allows the bottom spring seat 258 to be properly positioned relative to the mounting band 259. The side wall 262 can receive the edge 276 of the mounting band 259 in a clearance fit. Alternatively, the side wall 262 can receive the edge 276 in a press fit or interference fit. The end wall 280 forms a corresponding interface with the outer surface 274 of the mounting band 259. A line weld LWS is formed along the interface between the outer surface 274 and the end wall 280 to secure the bottom spring seat 258 to the mounting band 259.

[0061] Thus, the axle spring seat attachment assembly 252 according to the present disclosure eliminates the use of line welds on the axle 220, thereby eliminating or minimizing the formation and / or action of stress concentrations and allowing the use of thin-walled axles 220, which desirably reduces the weight and amount of material and manufacturing costs of the axle / suspension system 200. Due to the constant compression of the continuous window weld CWW by the loads of heavy vehicles, the axle spring seat attachment assembly 252 unexpectedly provides an improved connection, thereby reducing or eliminating reverse cycle fatigue and the resulting potential damage caused by vertical and fore-aft loads acting on the axle seat attachment assembly.

[0062] According to another aspect of the present disclosure, a pair of shaft spring seat attachment assemblies 352 are Figure 9-11 20, which is attached to the thin walled shaft 220. The axle spring seat attachment assembly 352 is shown in a bottom mount or under-mount configuration, wherein the leaf spring stack 224 is generally disposed below or beneath the shaft 220. However, it is contemplated that the axle spring seat attachment assembly 352 may be used with any other type and / or configuration of axle / suspension system, such as the axle / suspension system 200 described above.

[0063] Each shaft spring seat attachment assembly 352 includes a spring seat 356 secured to a mounting band 359 by suitable means such as welding. Each mounting band 359 is disposed at least partially around the shaft 220 and in close contact with the shaft. The mounting band 359 extends at least 180 degrees but less than 360 degrees around the center tube 206. More specifically, the mounting band 359 has an arcuate recess or inner surface 372 ( Fig.10 ), the arcuate recess or inner surface is complementary to the periphery of the upper half of the center tube 206 of the shaft 220. The inner surface 372 defines a dimension D1' ( Fig.11 ), which may range from significantly smaller than the outer diameter of the smallest center tube 206 on which the mounting band 359 is mounted to approximately the same outer diameter, depending on the method of installation. The mounting band 359 is oriented so that the opposite ends 357 of the mounting band are located in the front and rear quadrants Q4', Q2' ( Figure 5 ) in the corresponding quadrant.

[0064] The mounting band 359 is disposed or snapped onto the shaft 220 by applying an appropriate amount of force laterally using any suitable means, such as a mechanical hydraulic press (not shown) or with the aid of a suitable tool or adapter, such as a clamping system (not shown), so that the inner surface 372 of the mounting band contacts the shaft. Specifically, an appropriate amount of force is applied laterally across the shaft to the outer surface 374 of the mounting band 359 by the hydraulic press. The appropriate amount of force applied to the outer surface 374 can cause the mounting band 359 to elastically deform in the area around which it is disposed.

[0065] The fit of the inner surface 372 of the mounting band 359 to the shaft 220 goes beyond a simple force fit. While force fitting the inner surface 372 of the mounting band 359 to the shaft 220 generally produces uninterrupted contact, it also leaves discontinuous areas of gap at the interface between the outer surface of the upper portion of the shaft and the inner surface of the mounting band. As a result, gap areas at critical areas between the shaft 220 and the mounting band 359 can remain. However, an appropriate amount of force applied to the outer surface 374 provides a close contact that exceeds a force fit, a press fit, or an interference fit. Specifically, an appropriate amount of force applied to the mounting band 359 supported on the shaft 220 eliminates any significant gap between the outer surface of the upper portion of the shaft and the inner surface 372 of the mounting band. If there is no gap between the shaft and the mounting band 359, especially in critical areas between the shaft and the mounting band, such as where a weld may be formed, close contact can exist without actual deformation of the shaft 220. This intimate contact provides a constant relatively low preload or compression state between the center tube 206 and the mounting band 359, which greatly restricts the relative movement between the center tube and the mounting band. The intimate contact eliminates various stresses and improves reverse cycle fatigue strength, thereby preventing adverse effects on the integrity of the shaft 220 or the weld between the mounting band 359 and the center tube 206.

[0066] A window 370 is formed in the mounting band 359, typically above or near the top quadrant Q1' of the shaft 220. This allows a continuous window weld CWW (CWW) to be placed in the window 370 between the mounting band 359 and the shaft center tube 206. Fig. 9), to supplement the preload condition and enhance the fixation of the mounting band to the shaft. The continuous window weld CWW starts and stops at the same point within the window 370, so that the continuous window weld has no starting point or end point. As a result, stress concentrations caused by different starting and ending points can be reduced and / or eliminated. The reduction in stress concentration eliminates the need for thicker or heavier walled prior art shafts and allows the use of thin-walled shafts 220. Compared with the prior art spring seat assembly 52, which is welded to the front quadrant Q4 and rear quadrant Q2 of the shaft 20F respectively, whether by line welds or window welds, the placement of the continuous window weld CWW on the top quadrant Q1' of the shaft 220 also unexpectedly results in a stronger connection and less wear. The improved connection is at least partially due to the constant compression of the weight or load of the heavy vehicle on the continuous window weld CWW. Specifically, during the operation of the heavy vehicle, the top quadrant Q1' of the shaft 220 (wherein the continuous window weld CWW is positioned) is generally under constant compression. By means of constant compression on the continuous window weld CWW, reverse cycle fatigue caused by acceleration and braking of heavy vehicles, and the resulting vertical and fore-aft loads, can be mitigated or eliminated.

[0067] The spring seat 356 has a generally U-shape to surround a portion of the shaft 220. The spring seat 356 includes a pair of side walls 346, a pair of end walls 350, and a spring wall 348. The side walls 346, the end walls 350, and the spring wall 348 are formed separately and connected into a subassembly using a suitable method such as welding. Alternatively, the side walls 346, the end walls 350, and the spring wall 348 may be integrally formed as a single piece by any suitable method such as casting or forging. The spring wall 348 is generally planar and has a generally rectangular shape. The spring wall 348 is formed with an opening 334 to receive a pin, a pin, or a center bolt (not shown) that may extend through the leaf spring stack 224. The side walls 346 extend longitudinally in parallel and are spaced apart from each other by a width W1' ( Fig.10 ). The side walls 346 also extend substantially perpendicularly relative to the spring wall 348. Each side wall 346 has a generally U-shape, so that each side wall complementarily receives the center tube 206 in a press fit or interference fit manner. It is contemplated that the side walls 346 may also receive the center tube 206 in a clearance fit manner.

[0068] The end wall 350 is disposed between the side walls 346 and is perpendicular to the side walls 346. The end wall 350 extends from the longitudinally opposite ends of the spring wall 348 at a certain angle toward the center tube 206, thereby forming an opposite slope. Alternatively, the end wall 350 may extend perpendicularly from the longitudinally opposite ends of the spring wall 348. The end wall 350 generally extends so that the top end portion 355 of the end wall is spaced apart from the top end portion 345 of the side wall 346. Alternatively, the end wall 350 may extend so that the top end portion 355 of the end wall is coplanar with the top end portion 345 of the side wall 346 or extends beyond the top end portion 345 of the side wall 346.

[0069] According to another important aspect of the present disclosure, the spring seat 356 is indirectly attached to the shaft 220. Specifically, after the mounting band is attached to the center tube 206, the spring seat 356 is disposed above the mounting band 359 and is fixed only to the mounting band 359. The width W2' of the mounting band 359 is less than W1' of the spring seat 356. The spring seat 356 can then be disposed around the shaft 220 so that the portion of the mounting band 359 adjacent to the opposite end 357 is disposed between the side walls 346. As a result, the circumferential length L ( Fig.11 ) overlap. The side wall 346 of the spring seat 356 can receive the edge 376 of the mounting band 359 in a clearance fit, a press fit, or an interference fit. The end wall 350 forms an interface with the outer surface 374 of the mounting band 359. A line weld LWS is formed along the interface between the outer surface 374 and the end wall 350 to secure the spring seat 356 to the mounting band 359. After cooling, the line weld LWS will generate tension to maintain close contact between the mounting band 359 and the shaft 220. In addition, a pair of U-bolts (not shown) are disposed about the shaft 220 and connected to a bottom block (not shown) located below the leaf spring stack 224 to form the main connection between the leaf spring stack and the center tube 206, as is well known.

[0070] Thus, the axle spring seat attachment assembly 352 according to the present disclosure eliminates the use of line welds on the axle 220, thereby eliminating or minimizing the formation and / or effect of stress concentrations and allowing the use of thin-walled axles 220, which ideally reduces the weight and amount of material and manufacturing costs of the axle / suspension system 200. Due to the constant compression of the continuous window weld CWW by the loads of heavy vehicles, the axle spring seat attachment assembly 352 unexpectedly provides an improved connection, thereby reducing or eliminating reverse cycle fatigue and the potential damage caused by the resulting vertical and fore-aft loads acting on the axle seat attachment assembly.

[0071] According to yet another aspect of the present disclosure, a pair of shaft spring seat attachment assemblies 452 are Figure 12-15 4 is shown as being attached to a thin-walled shaft 220. The shaft spring seat attachment assembly 452 is shown as a top-mounted or top-mounted configuration. However, it is contemplated that the shaft spring seat attachment assembly 452 may be used with any other type and / or configuration of shaft / suspension system, such as the shaft / suspension system 200 described above.

[0072] Each axle spring seat attachment assembly 452 has an upper or top bracket or spring seat 456 and a bottom spring seat 458 that is rigidly secured to a mounting strap 459 ( Fig.13). Each mounting band 459 is at least partially disposed around the shaft 220 and in close contact with the shaft. The mounting band 459 extends at least 180 degrees but less than 360 degrees around the center tube 206. The mounting band 459 has an arcuate recess or inner surface 472 that is complementary to the periphery of the upper half of the center tube 206 of the shaft 220. The inner surface 472 defines a dimension D1″ that, depending on the mounting method, can range from significantly less than the outer diameter of the smallest center tube 206 on which the mounting band 459 is mounted to approximately the same as the outer diameter. The mounting band 459 is oriented so that the opposite ends 457 of the mounting band are located in respective quadrants of the front and rear quadrants Q4′, Q2′ of the shaft 220, respectively. The mounting band 459 includes a central protrusion 496 that protrudes from the end 457 and forms a respective pair of laterally extending shoulders 461.

[0073] According to an important aspect of the present disclosure, the mounting band 459 includes a locator 492. The locator 492 can be a ring formed from the mounting band 459 using any suitable method such as laser cutting. Specifically, as described above, the locator 492 is formed before the mounting band 459 has been formed with an arcuate shape. More specifically, a window 470 having a continuous inner perimeter is formed in the mounting band. Then, an opening 494 is formed concentrically in the mounting band 459 at least partially around the continuous inner perimeter of the window 470, thereby forming the locator 492. Therefore, the locator 492 has a shape similar to the opening 494 in the mounting band 459 or is concentric with the opening and is disposed in the opening. Alternatively, the locator 492 can be formed after the inner surface 472 of the mounting band 459 has been provided with the arcuate shape. It is also conceivable that the locator 492 and the mounting band 459 can be formed separately. The opening 494 is generally formed in the mounting band 459 so that the opening, and thus the retainer 492 and the window 470, can be away from the neutral axis plane N′ ( Figure 5 ) to minimize the thickness of the shaft. Specifically, the locator 492 and window 470 can be positioned around the front or rear portion of the shaft 220 at an angle α above or below the neutral axis plane N'. Specifically, the locator 492 and window 470 can be positioned and centered around the shaft 220 at a circumferential distance α in the front quadrant Q4' or the rear quadrant Q2' or in the top quadrant Q1, respectively, which is anywhere about forty-five degrees above or below the neutral axis plane N'. More preferably, the locator 492 and window 470 can be positioned around the rear portion of the shaft 220 at a circumferential distance α of about forty-five degrees above the neutral axis plane N'.

[0074] The inner dimension D3 of the opening 494 is greater than the outer dimension D2 of the locator 492. Before the mounting belt 459 is provided with an arcuate shape, the minimum difference between the inner dimension D3 of the opening 494 and the outer dimension D2 of the locator 492 can be in the range of about 0.010 inches to about 0.060 inches, more preferably in the range of about 0.010 inches to about 0.040 inches. Once the mounting belt 459 is provided with an arcuate shape, the minimum difference between the inner dimension D3 of the opening 494 and the outer dimension D2 of the locator 492 can be relatively smaller near the inner surface 472 than at the outer surface 474. The inner dimension D4 of the window 470 is less than the outer dimension D2 of the locator 492. The inner dimension D4 of the window 470 is generally maximized to reduce fatigue. It is also conceivable that the locator 492, the opening 494 and the window 470 can have any other suitable continuous shape.

[0075] The locator 492 may also include one or more projections or ties 495, which connect the locator and the mounting belt 459 and are continuous between them. As a result, the locator 492 is at least partially attached to the mounting belt 459 and remains in the opening 494. The ties 495 may have any suitable size, shape and arrangement between the locator 492 and the mounting belt 459. The ties 495 contribute to the manufacture and installation of the mounting belt 459 and the locator 492, thereby preventing the separation or loss of the locator during the forming period before installation. The ties 495 are normally non-load-bearing structures, so that the ties may break during the installation of the mounting belt 459 or the operation of the heavy vehicle, thereby the locator 492 is disengaged from the mounting belt. Alternatively, the ties 495 may remain connected to the locator 492 and the mounting belt 459.

[0076] The mounting band 459 is disposed around or snapped onto the shaft 220 by applying an appropriate amount of lateral force using any suitable means, such as a mechanical or hydraulic press (not shown) or with the aid of a suitable tool or adapter, such as a clamping system (not shown), so that the inner surface 472 of the mounting band contacts the shaft. Specifically, an appropriate amount of force is applied to the outer surface 474 of the mounting band 459 laterally across the shaft 220 by the hydraulic press. The appropriate amount of force applied to the outer surface 474 of the mounting band 459 can cause the mounting band to elastically deform in the area around which it is disposed.

[0077] The fit of the inner surface 472 of the mounting band 459 to the shaft 220 goes beyond a simple force fit. While force fitting the inner surface 472 of the mounting band 459 to the shaft 220 generally produces uninterrupted contact, it also leaves discontinuous areas of gap at the interface between the outer surface of the upper portion of the shaft and the inner surface of the mounting band. As a result, areas of gap at critical areas between the shaft 220 and the mounting band 459 can remain. However, an appropriate amount of force applied to the outer surface 474 provides a close contact that exceeds a force fit, a press fit, or an interference fit. An appropriate amount of force applied to the mounting band 459 supported on the shaft 220 eliminates any gap between the outer surface of the upper portion of the shaft and the inner surface 472 of the mounting band. If there is no gap between the shaft and the mounting band 459, especially in critical areas between the shaft and the mounting band, such as where a weld may be formed, a close contact condition can exist without actual deformation of the shaft 220. This intimate contact provides a constant relatively low preload or compression state between the center tube 206 and the mounting band 459, which greatly limits the relative movement between the center tube and the mounting band. The intimate contact eliminates various stresses and improves reverse cycle fatigue strength, thereby preventing potential adverse effects on the integrity of the shaft 220 or the weld between the mounting band 459 and the center tube 206.

[0078] According to another important aspect of the present disclosure, the retainer 492 serves as a mechanical locking mechanism between the shaft 220 and the mounting band 459. Specifically, a continuous window weld CWW (CWW) is formed between the inner periphery of the window 470 of the retainer 492 and the center tube 206. Fig.13 ) to rigidly attach the locator 492 to the shaft 220. The continuous window weld CWW starts and stops at the same point within the window 470, so that the continuous window weld has no starting or ending point. As a result, stress concentrations caused by different starting and ending points can be reduced and / or eliminated, thereby eliminating the need for thicker or heavier prior art shafts and allowing the use of thin-walled shafts 220. Moreover, because the locator 492 is rigidly attached to the center tube 206 and disposed within the opening 494 of the mounting band 459, the locator significantly limits relative axial and circumferential movement between the mounting band and the shaft 220.

[0079] According to another important aspect of the present disclosure, the locator 492 is used to isolate the forces acting on the continuous window weld CWW from the mounting band 459. Specifically, the forces acting on the shaft 220 are transmitted to the continuous window weld CWW. However, since the tie 495 between the mounting band 459 and the locator 492 is non-load-bearing, the locator is separated from the mounting band when the force is applied to the tie. As a result, the mounting band 459 is relatively isolated from many forces on the continuous window weld CWW and the shaft 220.

[0080] The top spring seat 456 has an inverted generally U-shape that is at least partially complementary to the outer surface 474 of the mounting band 459. The top spring seat 456 includes a pair of side walls 446, a pair of end walls 450, and a spring wall 448. The side walls 446, the end walls 450, and the spring wall 448 are formed separately and connected into a subassembly by a suitable means such as welding. Alternatively, the side walls 446, the end walls 450, and the spring wall 448 can be integrally formed as a single piece by any suitable method such as casting or forging. The spring wall 448 is generally planar and has a generally rectangular shape. The spring wall 448 has an opening 434 to receive a pin or a center bolt (not shown) that can extend through the leaf spring stack 224.

[0081] The side walls 446 extend longitudinally in parallel and are spaced apart from each other by a width W1″ ( Fig.14 ). The side walls 446 also extend substantially perpendicularly relative to the spring wall 448. Each side wall 446 may also include a bracket portion 437 extending forwardly or rearwardly. The bracket portion 437 has a pair of laterally aligned openings 439 for receiving fasteners (not shown) for connection to a radius rod (not shown). Each side wall 446 has an inverted generally U-shape such that each side wall complementarily receives a mounting strap 459 in a press fit or interference fit manner. It is contemplated that the side walls 446 of the present disclosure may also receive the mounting strap 459 in a clearance fit manner.

[0082] End wall 450 is disposed between and perpendicular to side wall 446. End wall 450 may extend inwardly toward center tube 206 at an angle from longitudinally opposite ends of spring wall 448, thereby forming opposing slopes. Alternatively, end wall 450 may extend perpendicularly relative to longitudinally opposite ends of spring wall 448. End wall 450 generally extends such that bottom end 455 ( Fig.14 ) is recessed relative to the bottom end 445 of the side wall 446. Alternatively, the end wall 450 may be extended so that the bottom end 455 of the end wall is coplanar with the bottom end 445 of the side wall 446 or extends beyond the bottom end 445 of the side wall 446.

[0083] According to an important aspect of the present disclosure, the top spring seat 456 is indirectly attached to the shaft 220. Specifically, once the mounting band has been attached to the center tube 206, the top spring seat 456 is disposed above the mounting band 459 and is only secured to the mounting band 459. The mounting band 459 has a width W2A that is greater than the width W2B of the center protrusion 496 ( Fig.13). The width W2B of the central protrusion 496 is less than W1″ of the top spring seat 456. The top spring seat 456 is disposed about the mounting band such that the top spring seat is partially on or in contact with the mounting band. It is also contemplated that the top spring seat 456 may be disposed on the mounting band 459 such that an edge 476 of the mounting band may be coplanar or continuous with the side wall 446. The end wall 450 forms an interface with the outer surface 474 of the mounting band 459. A line weld LWS is formed along the interface between the outer surface 474 of the mounting band 459 and the end wall 450 of the top spring seat 456 to secure the spring seat to the mounting band. A line weld may also be formed between the side wall 446 of the top spring seat 456 and the edge 476 of the mounting band 459.

[0084] The bottom spring seat 458 is similar in structure and arrangement to the top spring seat 456. Specifically, the bottom spring seat 458 has a generally U-shape that is at least partially complementary to the bottom portion of the center tube 206 of the shaft 220. The bottom spring seat 458 includes a bottom plate 468, a pair of side walls 462, and a pair of end walls 480. The side walls 462, the end walls 480, and the bottom plate 468 are formed separately and connected into a subassembly by any suitable means, such as welding. Alternatively, the side walls 462, the end walls 480, and the bottom plate 468 can be integrally formed as a single piece by any suitable method, such as casting or forging. The bottom plate 468 is generally planar and generally rectangular. The bottom plate 468 includes one or more, but preferably four, integrally formed protrusions 466 that are coplanar with the bottom plate. Each protrusion 466 is adjacent to a respective corner of the bottom plate 468 and extends outwardly from the respective corner of the bottom plate 468. The bottom plate 468 may be formed with an opening 469 for receiving a pin or dowel (not shown) extending through the leaf spring stack 224 .

[0085] The side walls 462 extend in parallel and are spaced apart from each other by a width W3′ ( Figure 13-14 ). The sidewalls 462 also extend perpendicularly relative to the bottom plate 468 adjacent to the protrusions 466, such that the protrusions extend away from the sidewalls 462 in opposite directions perpendicular to the sidewalls 462. Each sidewall 462 has a generally U-shape such that each sidewall complementarily receives the center tube 206 in a press fit or interference fit manner.

[0086] Each protrusion 466 of the bottom plate 468 is formed with a corresponding opening 467. Each opening 467 receives the end of one of a pair of U-bolts (not shown) to form the main connection between the leaf spring stack 224 and the center tube 206, as is known. A series of guide walls 490 can be integrally formed with the protrusions 466 and extend perpendicularly relative to the protrusions 466. The guide walls 490 are adjacent and can abut or connect to the sidewalls 462. The guide walls 490 at least partially surround the threaded portion and / or shank portion of the U-bolt. During operation of a heavy vehicle, the U-bolt can engage the guide walls 490. The guide walls 490 provide a structure over which lateral and fore-and-aft forces acting on the U-bolts can be distributed. As a result, the protrusions 466 of the bottom plate 468 are less likely to be deformed due to the forces acting on the U-bolts.

[0087] The end walls 480 of the bottom spring seat 458 may extend angularly from the longitudinally opposite ends of the bottom plate 468 toward the center tube 206, thereby forming opposing slopes. Alternatively, the end walls 480 may extend perpendicularly from the longitudinally opposite ends of the bottom plate 468. Each end wall 480 is perpendicular to the side walls 462 and is disposed between the side walls 462. The end walls 480 generally extend such that the top end portions 481 of the end walls are recessed relative to the top end portions 463 of the side walls 462. Alternatively, the end walls 480 may extend such that the top end portions 481 of the end walls are coplanar with the top end portions 463 of the side walls 462 or extend beyond the top end portions 463 of the side walls 462.

[0088] According to another important aspect of the present disclosure, the bottom spring seat 458 is indirectly attached to the shaft 220. Specifically, the bottom spring seat 458 is disposed above the mounting band 459 and is fixed only to the mounting band 459. Specifically, the width W2b of each central protrusion 496 of the mounting band 459 is equal to or less than the width W3' extending between the side walls 462. The bottom spring seat 458 can be disposed around the center tube 206 of the shaft 220 so that the portion of the central protrusion 496 adjacent to each of the opposite ends 457 of the mounting band 459 is disposed between the side walls 462. As a result, the side walls 462 overlap the circumferential length (not shown) of the edge 477 of the central protrusion 496 of the mounting band 259. Once the bottom spring seat 458 is placed around the mounting band 459, each shoulder 461 of the mounting band engages a corresponding notch 464 formed in the top end portion 463 of the side wall 462. Thus, the shoulders 461 allow the bottom spring seat 458 to be properly positioned relative to the mounting band 459. The side wall 462 may receive the edge 477 of the central protrusion 496 of the mounting band 459 in a clearance fit. Alternatively, the side wall 462 may receive the edge 477 in a press fit or interference fit. The end wall 480 of the bottom spring seat 458 forms a corresponding interface with the outer surface 474 of the mounting band 459. A line weld is formed along the interface between the outer surface 474 of the mounting band 459 and the end wall 480 of the bottom spring seat 458 to secure the bottom spring seat to the mounting band.

[0089] Thus, the axle spring seat attachment assembly 452 according to the present disclosure eliminates the use of line welds on the axle 220, thereby eliminating or minimizing the formation and / or effect of stress concentrations and allowing the use of thin-walled axles 220, which desirably reduces the weight and amount of material and manufacturing costs of the axle / suspension system 200. The axle spring seat attachment assembly 452 also includes a locator 492 that isolates the forces acting on the axle 220 from the mounting band 459, thereby reducing or eliminating reverse cycle fatigue damage caused by the vertical loads and fore-aft loads that are thereby formed acting on the axle seat attachment assembly.

[0090] According to another aspect of the present disclosure, a pair of identical shaft spring seat attachment assemblies 552 are Figure 16-19 200. The axle spring seat attachment assembly 552 is shown attached to the thin walled axle 220. The axle spring seat attachment assembly 552 is shown as a bottom mounted or under mounted configuration. However, it is contemplated that the axle spring seat attachment assembly 552 may be used with any other type and / or configuration of axle / suspension system, such as the axle / suspension system 200 described above. Because the axle spring seat attachment assemblies 552 are identical, only one axle spring seat attachment assembly will be described below for the sake of clarity and brevity.

[0091] The shaft spring seat attachment assembly 552 includes a spring seat 556 that is secured to a mounting band 559 by suitable means such as welding. The mounting band 559 is disposed at least partially around the shaft 220 and in close contact with the shaft. The mounting band 559 extends at least 180 degrees but less than 360 degrees around the center tube 206. More specifically, the mounting band 559 has an arcuate recess or inner surface 572 ( Fig.16 and Fig.18 ), the arcuate recess or inner surface is complementary to the periphery of the upper half of the center tube 206 of the shaft 220. The inner surface 572 defines a dimension D1''' ( Fig.16 ), which may range from significantly smaller than the outer diameter of the smallest center tube 206 on which the mounting band 559 is mounted to approximately the same outer diameter, depending on the method of installation. The mounting band 559 is disposed about the shaft 220 such that the opposite ends 557 of the mounting band are located in the front quadrant Q4' and the rear quadrant Q2' of the shaft, respectively ( Figure 5 ). The mounting band 559 includes a pair of laterally spaced notches 598 formed near each of the opposing ends 557. Each pair of notches 598 forms a corresponding central protrusion 596 between the notches and a pair of lateral protrusions 597.

[0092] According to an important aspect of the present disclosure, the mounting band 559 includes a locator 592. The locator 592 can be a circle or ring formed by the mounting band 559 using any suitable method (e.g., laser cutting). Specifically, the locator 592 is formed by the mounting band 559 before the inner surface 572 of the mounting band has an arcuate shape as described above. More specifically, a window 570 having a continuous inner perimeter is formed in the mounting band. Then, an opening 594 is formed concentrically in the mounting band 559 at least partially around the window 570, thereby forming the locator 592. Therefore, the locator 592 has a shape similar to the opening 594 in the mounting band 559 or is concentric with the opening and is disposed in the opening. Alternatively, the locator 592 can be formed after the inner surface 572 of the mounting band 559 has been provided with an arcuate shape. It is also conceivable that the locator 592 and the mounting band 559 can be formed separately. The opening 594 is generally formed in the mounting band 559 so that the opening and thus the locator 592 and the window 570 can be positioned away from the horizontal or neutral axis plane N' to minimize the thickness of the shaft. Specifically, the locator 592 and the window 570 can be positioned above or below the neutral axis plane N' around the front or rear portion of the shaft 220 at an angle α. Specifically, the locator 592 and the window 570 can be positioned and centered around the shaft 220 at a circumferential distance α in the front quadrant Q4' or the rear quadrant Q2' or in the top quadrant Q1, respectively, which is anywhere about forty-five degrees above or below the neutral axis plane N'. More preferably, the locator 592 and the window 570 can be positioned around the rear portion of the shaft 220 at a circumferential distance α of about forty-five degrees above the neutral axis plane N'.

[0093] The inner dimension D3' of the opening 594 is greater than the outer dimension D2' of the locator 592. Prior to providing the mounting band 559 with the arcuate shape, the difference between the inner dimension D3' of the opening 594 and the outer dimension D2' of the locator 592 can be in the range of about 0.010 inches to about 0.060 inches, and more preferably in the range of about 0.010 inches to about 0.040 inches. Once the mounting band 559 is provided with the arcuate shape, the minimum difference between the inner dimension D3' of the opening 594 and the outer dimension D2' of the locator 592 can be relatively smaller near the inner surface 572 than at the outer surface 574. The inner dimension D4' of the window 570 is less than the outer dimension D2' of the locator 592. The inner dimension D4' of the window 570 is typically maximized to reduce fatigue. It is also contemplated that the locator 592, the opening 594 and the window 570 can have any other suitable continuous shapes and / or sizes, such as Fig.19 Shape and / or size shown.

[0094] The locator 592 may also include one or more projections or ties 595, which connect the locator and the mounting belt 559 and are continuous between them. As a result, the locator 592 is at least partially attached to the mounting belt 559 and remains in the opening 594. The ties 595 may have any suitable size, shape and arrangement between the locator 592 and the mounting belt 559. The ties 595 contribute to the manufacture and installation of the mounting belt 559 and the locator 592, thereby preventing the separation or loss of the locator before installation. The ties 595 are normally non-load-bearing structures, so that the ties may break during the installation of the mounting belt 559 or the operation of the heavy vehicle, thereby the locator 592 is disengaged from the mounting belt. Alternatively, the ties 595 may remain connected to the locator 592 and the mounting belt 559.

[0095] The mounting band 559 is disposed or snapped onto the shaft 220 by applying an appropriate amount of force laterally using any suitable means, such as a mechanical hydraulic press (not shown) or with the aid of a suitable tool or adapter, such as a clamping system (not shown), so that the inner surface 572 of the mounting band contacts the shaft. Specifically, an appropriate amount of force is applied to the outer surface 574 of the mounting band 559 laterally across the shaft 220 by the hydraulic press. The appropriate amount of force applied to the outer surface 574 can cause the mounting band 559 to elastically deform in the area around which it is disposed.

[0096] The fit of the inner surface 572 of the mounting band 559 to the shaft 220 goes beyond a simple force fit. While force fitting the inner surface 572 of the mounting band 559 to the shaft 220 will generally produce uninterrupted contact, it will also leave discontinuous areas of gap at the interface between the outer surface of the upper portion of the shaft and the inner surface of the mounting band. As a result, gap areas at critical areas between the shaft 220 and the mounting band 559 can be retained. However, an appropriate amount of force applied to the outer surface 574 provides a tight contact that exceeds a force fit, a press fit, or an interference fit. Specifically, an appropriate amount of force applied to the mounting band 559 supported on the shaft 220 eliminates any significant gap between the outer surface of the upper portion of the shaft and the inner surface 572 of the mounting band. If there is no gap between the shaft and the mounting band 559, particularly in critical areas between the shaft and the mounting band, such as where a weld may be formed, there can be tight contact without actual deformation of the shaft 220. This intimate contact provides a constant relatively low preload or compression state between the shaft center tube 206 and the mounting band 559, which greatly limits the relative movement between the center tube and the mounting band. The intimate contact eliminates various stresses and improves reverse cycle fatigue strength, thereby preventing adverse effects on the integrity of the shaft 220 or the weld between the mounting band 559 and the shaft.

[0097] According to another important aspect of the present disclosure, the retainer 592 serves as a mechanical locking mechanism between the shaft 220 and the mounting band 559. Specifically, a continuous window weld CWW (CWW) is formed between the inner periphery of the window 570 of the retainer 592 and the center tube 206. Fig.16 ) to rigidly attach the locator 592 to the shaft 220. The continuous window weld CWW starts and stops at the same point within the window 570, so that the continuous window weld has no starting or ending point. As a result, stress concentrations caused by different starting and ending points can be reduced and / or eliminated, thereby eliminating the need for thicker or heavier prior art shafts and allowing the use of thin-walled shafts 220. Moreover, because the locator 592 is rigidly attached to the center tube 206 and disposed within the opening 594 of the mounting band 559, the locator significantly limits relative axial and circumferential movement between the mounting band and the shaft 220.

[0098] According to yet another important aspect of the present disclosure, the locator 592 is used to isolate the forces acting on the continuous window weld CWW from the mounting band 559. Specifically, the forces acting on the shaft 220 are transmitted to the continuous window weld CWW. However, since the tie 595 between the mounting band 559 and the locator 592 is non-load-bearing, the locator is separated from the mounting band when the force is applied to the tie. As a result, the mounting band 559 is isolated from the forces on the shaft 220 and the continuous window weld CWW.

[0099] Specific reference Fig.18 , the spring seat 556 has a generally U-shape to surround a portion of the shaft 220. The spring seat 556 includes a pair of side walls 546, a pair of inclined end walls 550 and a spring wall 548. The side walls 546, the end walls 550 and the spring wall 548 are formed separately and connected into a subassembly using a suitable method such as welding. Alternatively, the side walls 546, the end walls 550 and the spring wall 548 can be integrally formed as a single piece by any suitable method such as casting or forging. The spring wall 548 is generally planar and has a generally rectangular shape. The spring wall 548 is formed with an opening 534 to receive a pin, a pin or a center bolt (not shown) that can extend through the leaf spring stack 224. The side walls 546 extend in parallel and are spaced apart from each other by a width W1 ''. The side walls 546 also extend substantially perpendicularly relative to the spring wall 548. Each side wall 546 has a generally U-shape so that each side wall complementarily receives the center tube 206 in a press fit or interference fit manner.

[0100] The end wall 550 is disposed between and perpendicular to the side walls 546. The end wall 550 extends from the longitudinally opposite ends of the spring wall 548 at a certain angle toward the center tube 206, thereby forming an opposite slope. Alternatively, the end wall 550 can extend perpendicularly relative to the longitudinally opposite ends of the spring wall 548. The end wall 550 generally extends so that the top end portion 555 of the end wall (only one is shown) is recessed relative to the top end portion 545 of the side wall 546. Alternatively, the end wall 550 can extend so that the top end portion 555 of the end wall is coplanar with the top end portion 545 of the side wall 546 or extends beyond the top end portion 545 of the side wall 546.

[0101] According to another important aspect of the present disclosure, the spring seat 556 is indirectly attached to the shaft 220. Specifically, the spring seat 556 is disposed over and secured only to the mounting band 559 after the mounting band is attached to the center tube 206. The width W2A' of the mounting band 559 is greater than the width W2B' of the center protrusion 596. The ratio of the width W2A' of the mounting band 559 to the width of the spring stack 224 (not shown) is in the range of about 1.70 to about 1.90. More preferably, the ratio of the width W2A' of the mounting band 559 to the width of the spring stack 224 is about 1.86. The width W2B' of the center protrusion 596 is less than W1''' of the spring seat 556. Once the mounting band 559 is disposed about the shaft 220, the spring seat 556 can be disposed about the shaft so that a portion of the center protrusion 596 is disposed between the side walls 546 of the spring seat. The portion of the mounting band 559 including the lateral protrusion 597 is disposed laterally adjacent to the side wall 546. As a result, the side wall 546 overlaps the edge 577 of the central protrusion 596 of the mounting band 559. The side wall 546 may receive the edge 577 of the central protrusion 596 in a clearance fit, a press fit, or an interference fit. The end wall 550 of the spring seat 556 forms an interface with the outer surface 574 of the mounting band 559. A line weld LWS (LWS) is formed along the interface between the outer surface 574 of the mounting band 559 and the end wall 550 of the spring seat 556. Fig.16 and 18 ) to secure the spring seat to the mounting band. After cooling, the line weld LWS will generate tension to maintain close contact between the mounting band 559 and the shaft 220. The line weld LWS can also be formed between the side wall 546 of the spring seat 556 and the outer surface 574 of the lateral protrusion 597 of the mounting band 559. In addition, a pair of U-bolts (not shown) or other suitable fasteners are arranged around the mounting band 559 above the lateral protrusion 597 and connected to the bottom block (not shown) to form the main connection between the leaf spring stack 224 and the shaft 220.

[0102] Thus, the axle spring seat attachment assembly 552 according to the present disclosure eliminates the use of line welds on the axle 220, thereby eliminating or minimizing the formation and / or effect of stress concentrations and allowing the use of thin-walled axles 220, which ideally reduces the weight and amount of material and manufacturing costs of the axle / suspension system 200. The axle spring seat attachment assembly 552 also includes a locator 592 that isolates the forces acting on the axle 220 from the mounting band 559, thereby reducing or eliminating the potential for reverse cycle fatigue damage due to the vertical loads and fore-and-aft loads that are thereby formed acting on the axle seat attachment assembly.

[0103] It is contemplated that the axle spring seat attachment assemblies 252, 352, 452, 552 according to the present disclosure may be used on any axle having any shape or thickness without affecting the overall concept or operation. It is also contemplated that the axle spring seat attachment assemblies 252, 352, 452, 552 according to the present disclosure may be used in conjunction with any type of heavy-duty vehicle axle / suspension system without affecting the overall concept or operation. It is further contemplated that the axle spring seat attachment assemblies 252, 352, 452, 552 according to the present disclosure may be of other materials, shapes, sizes, structures, etc. without affecting the overall concept or operation. It is further contemplated that the axle spring seat attachment assemblies 252, 352, 452, 552 according to the present disclosure may be used to mount any vehicle component, including brake system components, on an axle / suspension system without affecting the overall concept or operation.

[0104] Thus, a new and improved axle spring seat attachment assembly is simplified; an effective, safe, inexpensive and efficient structure is provided that eliminates the difficulties encountered with prior art spring seat assemblies; problems are solved and new results are achieved.

[0105] In the foregoing description, certain terms have been used for brevity, clarity, and understanding, but no unnecessary limitations are to be implied because such terms are used for descriptive purposes and are intended to be broadly interpreted except as required by the prior art.

[0106] The present disclosure has been described with reference to specific aspects. It should be understood that the description and illustration are exemplary only and not restrictive. After reading and understanding the present disclosure, others may think of potential modifications and changes, and it should be understood that the present invention includes all such modifications, changes and equivalent forms.

[0107] Having now described: the features, discoveries and principles of the invention; the manner of using and installing the axle spring seat attachment assembly; the features of construction, arrangement and method steps; and the advantageous, new and useful results obtained; new and useful structures, devices, elements, arrangements, processes, components and combinations are set forth in the appended claims.

Claims

1. A spring seat attachment assembly for an axle / suspension system having at least one leaf spring and an axle, the spring seat attachment assembly comprising: a mounting strap extending between 180 and 360 degrees around a portion of the shaft, the mounting strap including an opening having a continuous edge, the mounting strap being secured to the shaft only at a location distal from a neutral axis of the shaft by a continuous weld formed around the continuous edge; and A spring seat is provided for receiving the at least one leaf spring, the spring seat being secured to the mounting strap.

2. The spring seat attachment assembly of claim 1, wherein the mounting band is secured to the top portion of the shaft by the continuous weld formed around the continuous edge.

3. The spring seat attachment assembly of claim 1, wherein the mounting band further comprises an arcuate inner surface extending between a pair of edges, the arcuate inner surface having a shape complementary to the portion of the shaft.

4. The spring seat attachment assembly of claim 3, wherein the inner surface defines a dimension that is less than or equal to a dimension of the portion of the shaft prior to mounting the mounting band on the shaft; Wherein when the mounting band is mounted on the shaft, at least a portion of an interface between the portion of the shaft and the mounting band is gap-free.

5. The spring seat attachment assembly of claim 4, said interface between said portion of said shaft and said mounting band being in continuous compressive contact.

6. The spring seat attachment assembly of claim 1 , wherein the spring seat further comprises a pair of parallel side walls spaced apart by a distance having a first width, The mounting strip has a second width that is smaller than the first width, and the mounting strip is at least partially disposed between the pair of side walls.

7. The spring seat attachment assembly of claim 6, wherein the pair of side walls form at least one interface with the mounting band and are secured to the mounting band by at least one weld formed along the at least one interface.

8. The spring seat attachment assembly of claim 6, wherein the spring seat further comprises a pair of inclined walls disposed between and perpendicular to the pair of side walls.

9. The spring seat attachment assembly of claim 8, wherein the pair of inclined walls form at least one interface with the mounting band and are secured to the mounting band by at least one weld formed along the at least one interface.

10. A spring seat attachment assembly for an axle / suspension system having at least one leaf spring and an axle, the spring seat attachment assembly comprising: a mounting band having an opening, the mounting band extending at least 180 degrees but less than 360 degrees around a portion of the shaft; a locating structure at least partially separated from the mounting band and disposed within the opening, the locating structure having a continuous edge, the locating structure being secured to the shaft only at a location distal from a neutral axis of the shaft by a continuous weld formed around the continuous edge; and A spring seat is provided for receiving the at least one leaf spring, the spring seat being secured to the mounting strap.

11. The spring seat attachment assembly of claim 10, wherein the retaining structure further comprises a window defined by the continuous edge, the retaining structure substantially limiting relative movement between the mounting band and the shaft and isolating the mounting band from forces acting on the shaft.

12. The spring seat attachment assembly of claim 11, wherein the opening and the locating structure are disposed about the shaft away from a neutral axis of the shaft.

13. The spring seat attachment assembly of claim 12, wherein the locating structure is disposed about the shaft at 45° above or below the neutral axis.

14. The spring seat attachment assembly of claim 10, wherein the mounting band further comprises an arcuate inner surface extending between a pair of edges, the arcuate inner surface having a shape complementary to the shaft.

15. The spring seat attachment assembly of claim 14, wherein prior to mounting the mounting band on the shaft, the inner surface defines a dimension that is less than or equal to a dimension of the shaft; Wherein when the mounting band is mounted on the shaft, at least a portion of the interface between the shaft and the mounting band is gap-free.

16. The spring seat attachment assembly of claim 15, said interface between said shaft and said mounting band being in continuous compressive contact.

17. The spring seat attachment assembly of claim 10, wherein the spring seat further comprises a pair of parallel side walls spaced apart by a distance, the distance having a first width; The second width of at least a portion of the mounting strip is smaller than the first width, and the at least a portion of the mounting strip is at least partially disposed between the pair of side walls.

18. The spring seat attachment assembly of claim 17, wherein the spring seat further comprises a pair of inclined walls disposed between and perpendicular to the pair of side walls.

19. The spring seat attachment assembly of claim 18, wherein the pair of inclined walls form at least one interface with the mounting band and are secured to the mounting band by at least one weld formed along the at least one interface.

20. A method of assembling a spring seat attachment assembly for an axle / suspension system, the method comprising: Mounting straps provided; forming at least one window having a continuous perimeter in the mounting band corresponding to a position away from a neutral axis of the shaft; forming at least partially an opening in the mounting strip, wherein the opening is concentric with the at least one window; forming the mounting band into an arcuate shape complementary to a portion of the shaft; installing the mounting band on the top portion of the shaft, wherein an inner surface of the mounting band and an outer surface of the shaft form a gap-free interface; forming at least one continuous weld between the continuous perimeter of the at least one window and the shaft to attach the mounting band to the shaft only at a location distal from a neutral axis of the shaft; at least one spring seat disposed about the mounting band; and The at least one spring seat is secured to the mounting strap.

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