阅读说明：本技术 在车轴的管状轴体中提供互锁凹部 (Providing interlocking recesses in a tubular shaft body of an axle ) 是由 德克·格尔特·阿尔德林克 格尔特·埃弗茨 米歇尔·海德律克斯 马腾·弗兰克·恰兰·布吕安娅 于 2020-04-14 设计创作，主要内容包括：一种用于制造诸如挂车、半挂车或卡车的多用途车辆的轮轴的方法,其中轮轴包括中空的轴体,该中空的轴体包括厚度为t的钢制管状壁并且具有夹持区域,该夹持区域适于在使用中借助于张紧装置夹持在车辆悬架的夹持部件之间。互锁凹部被形成在夹持区域中。该互锁凹部通过将压模构件按压到管状壁的外表面中以形成凹口的成形工艺来形成。压模的尺寸和按压力使得管状壁的冲压表面部分上的表面压力局部地超过屈服点以形成凹口,并且按压力使得邻近于互锁凹部的管状壁部向内塑性凹陷一段距离,该距离至多对应于管状壁的厚度t。优选地,向内凹陷的距离在管状壁的厚度t的0至0.5倍的范围内。在替代方法中,互锁凹部通过在轴体的管状壁中摩擦钻出盲孔来形成。(A method for manufacturing an axle for a utility vehicle, such as a trailer, semi-trailer or truck, wherein the axle comprises a hollow body comprising a steel tubular wall of thickness t and having a clamping area adapted to be clamped in use between clamping parts of a vehicle suspension by means of a tensioning device. An interlock recess is formed in the clamping area. The interlocking recess is formed by a forming process that presses a die member into the outer surface of the tubular wall to form the recess. The dimensions and pressing force of the die are such that the surface pressure on the punching surface portion of the tubular wall locally exceeds the yield point to form the recess, and the pressing force causes the tubular wall portion adjacent to the interlocking recess to be plastically recessed inwardly by a distance at most corresponding to the thickness t of the tubular wall. Preferably, the distance of inward recess is in the range of 0 to 0.5 times the thickness t of the tubular wall. In an alternative method, the interlocking recesses are formed by friction drilling blind holes in the tubular wall of the shaft body.)

1. Method for manufacturing an axle for a utility vehicle, such as a trailer, a semi-trailer or a truck, comprising a hollow axle body comprising a steel tubular wall of thickness t and having a clamping area adapted to be clamped in use between clamping parts of a vehicle suspension by means of a tensioning device, wherein an interlocking recess is formed in the clamping area, characterized in that the interlocking recess is formed by a forming process of pressing a die member into an outer surface of the tubular wall to form a notch, wherein the die is dimensioned and the pressing force is such that a surface pressure on a pressed surface portion of the tubular wall locally exceeds a yield point to form the notch, and the pressing force causes a plastic depression of the tubular wall portion adjacent to the interlocking recess a distance at most corresponding to the thickness t of the tubular wall, preferably, said distance is in the range of 0 to 0.5 times the thickness t of said tubular wall.

2. The method of claim 1, wherein the forming process is a cold forming process.

3. A method as claimed in claim 1 or 2, wherein the axle comprises an axle end attached to each of the ends of a tubular axle body before the interlocking recess is formed in the axle body.

4. The method of any preceding claim, wherein the shaft body is provided with an outer surface coating before the interlocking recesses are formed in the shaft body.

5. The method of any of the preceding claims, wherein the shaft body is formed to have a substantially circular cross-section at least at the clamping area.

6. Method according to any one of the preceding claims, wherein the stamp is displaced back and forth in the longitudinal direction each time between two pressing movements, such that a notch is formed at each pressing movement, wherein the notches abut each other and together form one interlocking recess.

7. The method according to any one of the preceding claims, wherein the interlocking recess is formed to have an elongated shape with a longitudinal axis extending in an axial direction of the shaft body.

8. The method of any of the preceding claims, wherein a plurality of interlocking recesses are formed in the gripping region of the shaft body.

9. The method of claim 8, wherein the interlocking recesses are formed in a staggered pattern.

10. The method of claim 8, wherein the recesses are formed in a straight line.

11. The method of claim 10, wherein the recesses are formed with an intermediate bridge between longitudinal ends of successive ones of the recesses.

12. The method of any preceding claim, wherein the recess is formed with a tapered sidewall, wherein the depth of the tapered sidewall is less than the wall thickness of the tubular wall.

13. The method according to any one of the preceding claims, wherein the recess is formed with a tapered sidewall having an inclination with respect to a radial line through the center of the recess, wherein the inclination angle of the tapered sidewall is in the range of 0 ° -45 °, preferably in the range of 5 ° -20 °.

14. A method for forming an interlocking recess in a steel tubular axle body for a wheel axle of a utility vehicle, such as a trailer, a semi-trailer or a truck, characterized in that the interlocking recess is formed by a forming process, preferably a cold forming process, wherein a die member is pressed into the outer surface of a tubular wall to form a recess, wherein the die is dimensioned and pressed such that the surface pressure on a stamped surface portion of the tubular wall locally exceeds the yield point to form the recess, and the pressing force causes the tubular wall portion adjacent to the interlocking recess to be plastically recessed by a distance which corresponds at most to the thickness t of the tubular wall, preferably which is in the range of 0 to 0.5 times the thickness t of the tubular wall.

15. An axle of a utility vehicle, such as a trailer, semi-trailer or truck, made by the method according to any one of claims 1 to 13.

16. An air spring vehicle suspension comprising the axle of claim 15, and further comprising a pair of trailing arms pivotally attached to a vehicle chassis and clamped against a clamping region of the axle, and an air spring operating between the axle and the vehicle chassis.

17. Method for manufacturing an axle for a utility vehicle, such as a trailer, a semi-trailer or a truck, comprising an axle body comprising a steel tubular wall and having a clamping area adapted to be clamped in use between clamping parts of a vehicle suspension by means of a tensioning device, wherein an interlocking recess is formed in the clamping area, characterized in that the interlocking recess is formed by friction drilling a blind hole in the tubular wall of the axle body.

18. The method of claim 17, wherein an annular ridge surrounding the blind bore is formed on an outer surface of the tubular wall.

19. The method of claim 18, wherein the annular ridge is cut away.

20. The method of any of claims 17 to 19, wherein a plurality of interlocking recesses are formed in the gripping region of the shaft body by friction drilling.

21. The method of claim 20, wherein the interlocking recesses are formed in a staggered pattern.

22. The method of claim 20, wherein the recesses are formed in a straight line.

23. A method according to claim 17, wherein a gripping member, such as a trailing arm portion, a shaft pad or other gripping member, is arranged against the gripping region of the shaft body, and wherein the interlocking recess is formed by means of a friction drill hole through the gripping member and into the shaft body.

24. The method of claim 23, wherein the gripping member has a through hole through which a friction drilling tool passes to drill into the tubular wall of the shaft body.

25. The method of claim 24, wherein the friction drilling tool is retained in the bore in the clamp member and the recess formed in the shaft body.

26. The method of claim 23, wherein the boring tool forms a recess in the gripping member and a recess in the shaft, wherein the materials of the shaft and the gripping member melt/bond together.

27. The method of claim 26, wherein the boring tool is retained in two recesses.

28. The method of any one of claims 17 to 27, wherein the blind hole has a cylindrical shape.

29. The method of any one of claims 17 to 27, wherein the blind holes have a conical shape.

Technical Field

The present invention relates to a method for manufacturing an axle for a utility vehicle, such as a trailer, a semi-trailer or a truck, comprising an axle body comprising a steel tubular wall and having a clamping area adapted to be clamped in use between clamping parts of a vehicle suspension by means of a tensioning device, wherein an interlocking recess is formed in the clamping area.

Background

As a mere rough indication of the dimensions of such components, it should be noted that in practice a tubular axle body for a wheel axle of a utility vehicle may typically have an outer diameter of 146mm and a wall thickness of about 8mm-15 mm. However, it should be noted that other dimensions are possible.

In the field of wheel axle suspensions for utility vehicles, the axle body is usually a hollow tubular body with a circular cross section. The axle is rigidly attached to the trailing arm (trailing arm) by a clamping structure, which typically includes a bolt or U-bolt that clamps the axle to the trailing arm or to an intermediate component, such as an axle pad. Since the shaft body has a circular shape, it can better withstand torsional loads than, for example, a square shaft. The torsional load is mainly generated by the roll motion of the vehicle, which is transmitted to the axle body via the clamping device. However, the circular shape of the shaft body also has the disadvantage that it is more difficult to lock the shaft body in the rotational direction than other components (e.g., a shaft body having a square cross section). Over the years, many solutions for interlocking shafts in the direction of rotation have been disclosed. One solution is to provide a recess in the axle body and provide a protrusion on one of the clamping components (e.g., the axle seat of the trailing arm or the axle seat of the axle pad). In particular, one solution provides a recess by deformation of the shaft body, thus eliminating the need for machining.

EP1334848 discloses an example in which a tubular shaft body is provided with interlocking recesses by pressing a ball segment into the outer surface of the shaft body. A disadvantage of this known method of forming interlocking recesses is that it requires a counter shape to be introduced into the tubular shaft body and to act as a backing for the shaft body wall to prevent deformation of the circular shape except for the required recesses.

Another example is known from EP2499009, in which an elongate recess having a circular cross-sectional shape is formed in the outer surface of the tubular shaft body to provide an interlocking recess. In practice, the method is performed without a backing member for supporting the interior of the shaft body during the formation of the recess. However, this requires heating the shaft.

Providing both a backing member in the shaft body or heating the shaft body results in the necessity of forming the interlocking recesses at an early stage of the shaft manufacturing process, particularly before the shaft end (axle stub) is welded to the end of the shaft body and/or the shaft body is coated with a (corrosion-resistant) protective coating. In practice this means that the axle manufacturer must provide interlocking recesses which may have different configurations for different customers, typically vehicle (e.g. (semi-) trailer) manufacturers or vehicle suspension manufacturers. It would be further advantageous to provide the interlocking recess after the shaft is manufactured and thus after the shaft is provided with a shaft end and coated.

Disclosure of Invention

It is an object of the present invention to provide a method for manufacturing an axle, in which interlocking recesses can be formed in a shaft body at the final stage of a shaft manufacturing process.

This object is achieved by a method for manufacturing an axle for a utility vehicle, such as a trailer, a semi-trailer or a truck, comprising a hollow axle body comprising a steel tubular wall of thickness t and having a clamping area adapted to be clamped in use between clamping parts of a vehicle suspension by means of a tensioning device, wherein an interlocking recess is formed in the clamping area. The interlocking recess is formed by a forming process of pressing a die member into the outer surface of the tubular wall to form the recess, wherein the die is dimensioned and the pressing force is such that a surface pressure on a punching surface portion of the tubular wall locally exceeds the yield point to form the recess, and the pressing force is such that the tubular wall portion adjacent to the interlocking recess is plastically recessed inwardly by a distance which corresponds at most to the thickness t of the tubular wall, preferably in the range of 0 to 0.5 times the thickness t of the tubular wall.

The invention is based on the following insight: if the outer surface area of the shaft body pressed inward by the press mold is small relative to the diameter and wall thickness of the shaft body, the resistance of the shaft body material pressed inward is smaller than the bending resistance of the tubular wall. The total pressing pressure may be kept small enough so that the shaft body does not deform as a whole, but rather the surface of the shaft body locally experiences a sufficiently high pressure to cause plastic deformation. Thus, with the method of the invention, very local deformations are possible and thus very local recesses with well-defined edges are formed. Therefore, the inner side of the shaft body does not have to be supported by the backing member to maintain the circular shape of the shaft body.

Furthermore, the method according to the invention may be performed by a cold forming process, which is advantageous in that heating the shaft body will have less damage to at least the material properties and the protective coating of the shaft body. In addition, corrosion resistant coatings, which may be cathodic dip paint (KTL), which may be reheated to warm form, may generate harmful fumes. Such smoke formation is avoided by the method according to the invention.

Another advantage of the method according to the invention is that it allows the suspension manufacturer to determine the distance between the axle clamping areas and thereby the width between the trailing arms that is deemed appropriate for a particular suspension.

Preferably, the forming process is therefore a cold forming process. However, it is conceivable to preheat the surface of the shaft body very locally (e.g., by induction heating) before pressing the die against the surface to locally lower the yield point.

As a result of the method according to the invention as defined in claim 1, the recess has relatively sharp edges and contours, since the surrounding wall portion adjacent to the recess is not plastically deformed, or at least only to a small extent, by the pressure. At the same time, the shaft body maintains its strength at the concave portion. This is in contrast to making the recess by a machining operation (e.g., milling), which would result in the recess having sharp and well-defined edges, but also in significant shaft body weakening.

Preferably, the axle includes an axle end attached to each of the ends of the tubular axle body prior to forming the interlocking recess in the axle body. In this way, it is not necessary that the axle manufacturer provide the interlocking recesses, but it can be done by the suspension manufacturer or the vehicle manufacturer as desired.

Preferably, the shaft body is provided with an outer surface coating prior to forming the interlocking recesses in the shaft body. Furthermore, this has the following advantages: the axle manufacturer can provide all the necessary measures for the axle and can manufacture a specific interlocking recess configuration on site at the suspension or vehicle manufacturer, depending only on its specifications.

Although the method according to the invention may be performed on a tubular shaft body having any desired shape, it is in practice most useful when manufacturing shafts having a shaft body as follows: the shaft body, at least at the clamping area, is formed with a substantially circular cross section, since such a circular cross section in fact requires an interlocking device to prevent the shaft body from rotating in the clamping device.

In a possible embodiment of the method according to the invention, the stamp is displaced back and forth in the longitudinal direction each time between two pressing movements, so that a notch is formed at each pressing movement, wherein the notches abut each other and together form one interlocking recess. This particular method offers the possibility of manufacturing interlocking recesses that are larger than the notches that constitute them. Without wishing to be bound by dimensions, when the wall of the shaft body has a thickness of 8-15 mm, the entire recess in a practical example may have a length of 30mm, a width of 10mm and a depth of 6 mm. In practice, the tubular shaft body typically has an outer diameter of 146mm, but other diameters are also used. In practice, two or three notches forming a recess are at least necessary to provide a sufficiently strong interlock of the protrusion in the recess. However, it is also conceivable to provide one longer recess, for example having a length of 90mm, instead of three aligned recesses separated by a bridge.

An interlocking recess is formed in the shaft body to enable locking of the shaft in a circumferential direction relative to other clamping components, such as axle seats, axle pads, or other clamping components of the trailing arm. In particular, such a clamping member will have an associated protrusion, for example, an elongated key-like protrusion integrally formed on the clamping member, or a separate key received in an interlocking recess in the shaft body and an interlocking recess in the clamping member.

Preferably, the interlock recess is formed to have an elongated shape with a longitudinal axis extending in the axial direction of the shaft body.

In a possible method according to the invention, a plurality of interlocking recesses are formed in the clamping region of the shaft body. These interlocking recesses may be formed in a staggered pattern. Another option is to form the recesses in a straight line. In a staggered or aligned pattern, the elongated recesses all extend parallel to the axial direction of the shaft body.

Preferably, the recesses are formed with an intermediate bridge between longitudinal ends of successive ones of the recesses. The intermediate bridge provides rigidity to the tubular wall. However, there may be embodiments in which the bridge may be omitted and the recesses merged to form one large recess.

Preferably, the recess is formed with a tapered side wall, wherein the depth of the tapered side wall is less than the wall thickness of the tubular wall. By forming the recesses in this manner, the force caused by the torsional load in the circumferential/tangential direction of the shaft body exerted by the interlocking projections received in the interlocking recesses is exerted only in the wall of the tube, not radially inward from the wall of the tube. This force is thereby optimally absorbed by the shaft body.

In addition, the tapered sidewalls of the recess allow the interlocking projections to be installed within greater dimensional tolerances. Further, when the protrusion is slightly larger than the recess, a smaller shear load is applied to the tubular wall. Another advantage of the tapered sidewalls is that the die members are less prone to wear.

According to a second aspect of the invention, the object of the invention is also achieved. This aspect relates to a method for manufacturing an axle for a utility vehicle, such as a trailer, a semi-trailer or a truck, the axle comprising a body comprising a steel tubular wall and having a clamping area adapted to be clamped in use between clamping parts of a vehicle suspension by means of a tensioning device, wherein an interlocking recess is formed in the clamping area, wherein the interlocking recess is formed by friction drilling a blind hole in the tubular wall of the body.

During friction drilling, a hard metal heat resistant tool is rotated and pressed into the surface of the tubular wall of the shaft body at high speed. Due to the frictional heat, the tubular wall is locally heated and becomes flowable. In the method according to this aspect of the invention, the tool is not pushed completely through the tubular wall, so that a blind hole is formed in the shaft body. The blind hole may serve as an interlocking recess for an interlocking protrusion formed on a trailing arm, axle pad, or other clamping member that engages the axle body. The advantage of a blind hole is that it does not compromise the structural integrity of the axle body and maintains the strength of the axle tube as much as possible. The friction drilling can be done from the outside without the need for a backing member inside the tubular shaft body. Furthermore, the frictional heat is very local, whereby damage to possible surface coatings of the shaft body is eliminated only at precise locations of the recesses.

The axle may already include an axle end that is attached to each of the ends of the tubular axle body prior to forming the interlocking recesses in the axle body. In this way, it is not necessary that the axle manufacturer provide the interlocking recesses, but it can be done by the suspension manufacturer or the vehicle manufacturer as desired.

Further, the shaft body may have been provided with an outer surface coating prior to forming the interlocking recesses in the shaft body. And, this has the following advantages: the axle manufacturer can provide all the necessary measures for the axle and can manufacture a specific interlocking recess configuration on site at the suspension or vehicle manufacturer, depending only on its specifications.

The friction welding forms a circular ridge (collar) on the outer surface of the tubular wall, which surrounds the hole. The ridge may be left there, but the ridge may also be cut off.

As described above, a plurality of interlocking recesses may be formed in the clamping area of the shaft body by friction drilling. The interlocking recesses may be formed in a staggered pattern, but may alternatively be formed in a straight line.

In a possible embodiment of the method, a clamping member, such as a trailing arm portion, a pad, or other clamping member, is arranged against a clamping area of the shaft body, and the interlocking recesses are formed by means of friction drilling through the clamping member and into the shaft body. Thus, according to this method, the blind hole is not formed directly in the shaft body, but rather a hole is formed in the clamping member from the side facing away from the shaft body.

In a particular embodiment, the clamping member has a through hole through which a friction drilling tool is passed to drill into the tubular wall of the shaft.

In a possible variant of the method, the friction drilling tool is held in a hole in the clamping member and a recess formed in the shaft body. As the clamping member and shaft cool, the friction drilling tool is secured.

In a possible variant of the method, the drilling tool forms a recess in the clamping member and a recess in the shaft body, wherein the materials of the shaft body and the clamping member are melted/bonded together. Preferably, the drilling tool is held in both recesses.

The method according to both aspects of the invention, whether done by a cold forming process or by friction drilling, does not require that the tubular shaft body wall is supported from the inside during the production of the recess. On the other hand, the outside of the shaft body may be supported, preferably, as much as possible over a part of the circumferential direction of the shaft body. This helps prevent plastic deformation of the shaft body due to the formation of the interlocking recess.

It should be noted that the interlocking recesses formed in the shaft body provide the greatest advantage in shaft bodies having a circular shape (particularly a circular outer profile) which tend to loosen and rotate relative to the clamping arrangement due to torsional loads. However, it is also conceivable to use the method according to the invention for providing interlocking recesses in axles having other outer contours, for example rectangular, in particular square outer contours, which are also frequently used in air spring wheel axle suspensions.

Drawings

The invention is further illustrated in the following detailed description with reference to the drawings, in which:

figure 1 schematically shows a side view of an embodiment of an air spring wheel axle suspension comprising a shaft body produced by a method according to the invention,

figure 2 shows a longitudinal section through the axle clamping arrangement of the wheel axle suspension of figure 1,

figure 3 shows schematically a side view of another embodiment of an air spring wheel axle suspension comprising a shaft body produced by the method according to the invention,

figure 4 shows a longitudinal section through the axle clamping arrangement of the wheel axle suspension of figure 3,

figure 5 shows schematically a side view of a further embodiment of an air spring wheel axle suspension comprising a shaft body produced by the method according to the invention,

figure 6 shows a longitudinal section through the axle clamping arrangement of the wheel axle suspension of figure 5,

figures 7 and 8 show a method according to the first aspect of the invention in perspective view and in cross-section respectively,

figures 9 and 10 show a longitudinal section and a cross section respectively of a portion of a shaft body wall resulting from the method shown in figures 7 and 8,

figures 11 and 12 show longitudinal and cross-sections respectively of a portion of a shaft body wall resulting from the method shown in figures 7 and 8 in combination with a pillow,

figure 13 shows an isometric view of a portion of the pillow block shown in figures 11 and 12,

figures 14A-14C show cross-sections of a shaft body having different amounts of plastic inward deformation on the side where the notch is formed,

fig. 15-18 show isometric views of a shaft body made by a method according to the invention, the shaft body having differently configured interlocking recesses formed therein,

figure 19 shows a longitudinal cross-section of a portion of a shaft body wall of the shaft body of figure 17 in combination with a shaft pad,

figures 20-23 show a method according to the second aspect of the invention in front view, perspective view and cross-sectional view respectively,

figures 24-26 show cross-sectional and longitudinal sections respectively of a portion of a shaft body wall resulting from the method shown in figures 20-23 in combination with a pillow,

figure 27 shows a portion of the pillow block shown in figure 26,

fig. 28 shows an isometric view of a shaft body made by a method according to the invention, the shaft body having a different configuration of interlocking recesses formed therein,

fig. 29 shows an isometric view of a shaft body made by a method according to the invention, the shaft body having the same construction as in fig. 21, with the circumferential ridge removed,

figure 30 shows a cross section of a portion of a shaft body manufactured by the method shown in figures 20-23,

figures 31A-31D illustrate an alternative method according to the second aspect of the invention,

FIGS. 32A-32C illustrate alternative methods, and

fig. 33A-33C illustrate another method according to the second aspect of the invention.

Detailed Description

The present invention relates to a method for manufacturing an axle for a utility vehicle, such as a trailer, a semi-trailer or a truck. Fig. 1 shows an air spring wheel axle suspension 1, in which the axle body is produced by the method according to the invention.

The wheel axle includes a tubular shaft body 2 extending in the lateral direction of the vehicle. The shaft body 2 is hollow and has a steel tubular wall with a thickness t (see fig. 2) and a circular profile.

In practice, a typical tubular shaft body 2 has an outer diameter of 146mm, but other dimensions are possible. For example, a shaft body having an outer diameter of 127mm is also known. The thickness t may be somewhere in the range of 8mm-15mm, for example 10 mm.

The suspension 1 further comprises trailing arms 3 on either lateral side of the vehicle chassis, the trailing arms 3 being attached to the axle body 2 and extending in the longitudinal direction of the vehicle. The trailing arm 3 has an integrally formed eyelet 31 at a front end and a shaft seat 32 at a rear end thereof. In the particular embodiment shown, the trailing arm is made of spring steel and has a spring portion 33 between the eyelet 31 and the axle seat portion 32. The spring portion 33 is formed as a leaf spring and is designed to elastically deform during use of the vehicle, so that the assembly of two parallel trailing arms and a shaft body attached thereto can stabilize the vehicle by counteracting roll motions of the vehicle. The eyelet 31 is adapted to pivotally couple the front end of the trailing arm 3 to a bracket (bearing cradle) attached to the vehicle chassis by means of a pivot pin (e.g. a pivot bolt).

Associated with each of the trailing arms 3 is a corresponding trailing arm 4. The rear arm 4 includes a shaft seat portion 42 and a support arm 41 for the air spring 5. The support arm 41 extends from the shaft seating portion 42 toward the rear. In fig. 1, the air spring 5 is shown having a lower end mounted on a support arm 41. The upper end of the air spring 5 is attached to the vehicle chassis.

The axle body 2 is attached to the trailing arm 3 by means of a clamping device, which will be further elucidated with reference to fig. 2.

The axle seating portion 32 of the trailing arm 3 and the axle seating portion 42 of the rear arm 4 each have a concavely formed axle engaging surface 35 and 45, respectively. The shaft body 2 has a clamping region adapted to be clamped, in use, between the concavely formed shaft engaging surfaces 35, 35 of the two shaft seat portions 32, 42. The axle seats 32 and 42 form a clamping member which is clamped around the clamping area of the axle body 2 by means of a tensioning device, in particular a tensioning bolt. In the embodiment shown in fig. 1 and 2, the front end of the clamping device is tensioned by a U-bolt 7, which U-bolt 7 extends with a U-shaped bend over a nose 46 of the axle seat 42 of the rear arm 4 and with two legs of the U-shape through a counter plate 6 extending transversely on the top side of the trailing arm 3. Nuts 10 screwed on the legs of the U-bolt 7 fasten the front end of the clamping device. At the rear end of the clamping device the axle seats are fastened towards each other by means of bolts 8 and nuts 9. The bolt 8 extends through holes in the respective rear ends of the shaft seating portions 32 and 42. In an alternative embodiment, the rear ends of the axle seat parts may also be clamped together by means of a plurality of bolts or U-bolts.

An interlock recess 11 is formed in the clamping area of the shaft body 2. The interlocking recess 11 cooperates with an interlocking projection 47, which in the particular embodiment of fig. 1 and 2, 47 is integrally formed on the axle seating 42 of the rear arm 4 and in particular extends from the concave engagement surface 45 of the axle seating 42 of the rear arm 4. The axle seat portions 32 and 42 are rigidly clamped on the clamping area of the axle body 2. However, in practice, the clamping force alone is not sufficient to prevent relative movement between the circular shaft body and the clamping members 32, 42 in the rotational direction (tangential direction). Thus, interlocking between the interlocking recess 11 and the interlocking projection 47 is provided. Thus, torsional loads on the clamping device (especially those due to roll movements of the vehicle) will not result in relative movement between the axle body 2 and the clamping members 32, 42 and eventual possible loosening of the clamping device which may lead to failure of the suspension 1.

In fig. 3 and 4, a wheel axle suspension is shown, in which the trailing arm is a one-piece, integrally formed trailing arm 103. The trailing arm 103 is made of spring steel. The trailing arm 103 has an eyelet 131, an axle seat 132, and a spring portion 133 between the eyelet 131 and the axle seat 132. The trailing arm 103 has an integral support arm 141 for the air spring, the support arm 141 being integrally formed on the rear end of the axle seat. The axle body is clamped in the axle seating 132 by means of a U-bolt 107 against a concavely formed axle engagement surface 135, the U-bolt 107 extending with its bend 107A around the axle body, wherein one of the legs 107B extends upwards and along a lateral side of the trailing arm on the front side of the axle body and the other leg 107C extends upwards and along a lateral side of the trailing arm 103 on the rear side of the axle body. The strap plate 106 engages the upper side of the trailing arm 103 and contains holes through which the legs 107B and 107C of the U-bolt 107 pass. U-bolt 107 is tightened against strap 106 by nut 110.

The shaft body 2 includes an interlock recess 11. An interlocking protrusion 147 is integrally formed on the axle seat 132 of the trailing arm 103 and protrudes from the concave surface 135. The function of which is the same as that described above with reference to fig. 1 and 2.

In fig. 5 and 6 another embodiment of the wheel axle suspension is shown. In contrast to the embodiment of the previous figures, the shaft body 2 in this embodiment is not directly seated against the trailing arm, but an intermediate component, a so-called axle pad, is arranged against the trailing arm, which axle pad forms the axle seat.

The trailing arm is a one-piece, integrally formed trailing arm 203. The trailing arm 203 is made of spring steel. The trailing arm 103 has an eyelet 131 and a spring portion 133 extending from the eyelet toward the rear. The trailing arm 203 has an integral support arm 241 for the air spring, which support arm 241 is integrally formed on the rear portion. Between the spring arm and the support arm 241 there is an intermediate portion 232, at which intermediate portion 232 the shaft body 2 is attached to the trailing arm 203. On the lower side of the intermediate portion 232, the shaft pads 301, 701 are positioned. The axle body 2 is clamped on the concavely formed axle engagement surface 335 of the axle pad 301, 701 by means of a U-bolt 107, the U-bolt 107 extending with its bend 107A around the axle body 2, wherein one of the legs 107B extends upwards on the front side of the axle body 2 and along a lateral side of the trailing arm 203 and the other of the legs 107C extends upwards on the rear side of the axle body 2 and along a lateral side of the trailing arm 103. The strap plate 106 engages the upper side of the trailing arm 103 and contains holes through which the legs 107B and 107C of the U-bolt 107 pass. U-bolt 107 is tightened against strap 106 by nut 110. Thereby, the shaft pads 301 and 701 are sandwiched between the shaft body 2 and the trailing arm 203.

The shaft body 2 includes an interlock recess 11. The interlocking protrusions 347, 747 are integrally formed on the shaft seating portions of the shaft pads 301, 701, and protrude from the concave engagement surface 335. The function of which is the same as that described above with reference to fig. 1 and 2.

The above-described embodiments of the wheel axle suspension are to be regarded as non-limiting examples only. However, many variations are conceivable.

According to the present invention, the interlocking recess 11 is formed in the shaft body 2 by a forming process of pressing a die member into the outer surface of the tubular wall to form a notch. The inner side of the tubular wall need not be supported when forming the recess to prevent excessive deformation of the shaft body around the recess.

In fig. 7 and 8, the shaft body 2 is shown in which three interlocking recesses 11 are in line with each other in the longitudinal direction of the shaft body 2. The die member 501 is pressed into the outer surface 2A of the shaft body and forms a notch. The die member 501 has a tip 502 adapted to engage a surface in which a recess must be formed. The dimensions of the stamp 502, in particular the dimensions of the tip 502, are small enough that the surface pressure on the stamping surface portion of the tubular wall locally exceeds the yield point to form the recess. The pressing force required to form the recess with the relatively small stamp 502 is so low that the tubular wall portion adjacent to the interlocking recess 11 is not plastically deformed in the radially inward direction, which deformation is sometimes referred to as "denting", or at most dented to a distance corresponding at most to the thickness t of the tubular wall. In practice, the depression is preferably kept in the range of 0 to 0.5 times the thickness t of the tubular wall.

Fig. 14A shows a case where the wall portion around the recess 11 is not deformed, thereby obtaining a sharp and well-defined edge of the recess 11. An advantage of having no or only a small inward deformation of the peripheral region 12 of the interlocking recess 11 is that the interlocking projections 47, 147, 347 do not easily disengage or "roll out" from the interlocking recess 11. The smaller the deformation in the region 12, the more firmly the protrusion can be held in the recess 11. The following is shown in fig. 14B: wherein the surrounding area, in particular the area 12 along the longitudinal edges of the interlocking recess 11, is deformed inwards and thus deviates from the original circular shape. In the state shown in fig. 14B, the adjacent wall portion at the edge of the recess 11 is moved inward by a distance corresponding to the thickness t of the tubular wall of the shaft body. In practice, the thickness t may be about 10mm, and the inward deformation will be in the range of 0 to 0.5 times the thickness t.

In a practical embodiment, the recess 11 shown in fig. 7 and 8 may have a longitudinal length of about 30mm, a width of 10mm and a depth of 6 mm. The longitudinal length of the tip 502 of the stamp 501 may be rather small, for example 10-15 mm, and the recess 11 is made by pressing the notch, then retracting and translating the stamp several times and pressing the overlapping notches to form the whole recess 11. One or more recesses may be formed in the outer surface 2A of the shaft body 2 as such. For example, three recesses 11 are in line in the longitudinal direction of the shaft body 2, as shown in fig. 7 to 9. As can be seen in fig. 11 to 12, the shaft washer 301 with three protrusions 374 (see fig. 13) is received in three recesses 11. In this way, the interlocking interface between the protrusion 374 and the recess 11 is provided with sufficient surface to prevent deformation due to torsional loads on the clamping arrangement of the axle.

With the method of the present invention, different recess patterns can be manufactured. Thus, the surface area of the interlocking interface between the recess and the protrusion can be varied and the surface pressure can be varied and maintained between safety limits. Non-limiting examples of recess patterns are shown in fig. 15-18.

In fig. 15, the clamping area of the shaft body 2 may have two interlocking recesses 11 in line with a considerable distance between the two interlocking recesses 11.

In fig. 16, the clamping area of the shaft body 2 is shown to have one long recess 11A.

In fig. 17, the clamping region of the shaft body 2 is shown to have two parallel long recesses 11B. In fig. 19, a cross section of the shaft body 2 shown in fig. 17 is shown, in which a shaft pad 301B having two parallel protrusions 374B is received in a parallel recess 11B formed in the shaft body 2.

In fig. 18, the clamping region of the shaft body 2 is shown with three recesses 11, 11', 11 ", wherein the central recess 11' is offset from the other two aligned recesses 11, 11".

The cross-section of the recess 11 may have different shapes. It may be a V-groove, as shown in fig. 10A, wherein the side wall extends at an angle α (e.g. 45 °) relative to a radius R at the center of the recess 11. It may also be a recess 11 with vertical side walls parallel to the radius R at the recess as shown in fig. 10B. There may be many cross-sectional recess shapes in the range between the shape of fig. 10A and the shape of fig. 10B. In fig. 10, a practical embodiment is shown, wherein the side wall extends at an angle of about 10 ° with respect to the radius R at the recess 11. The side wall bears against a side wall of a projection which, in use, is received in the recess.

In addition to the above-described method of forming one or more interlocking recesses in a shaft body by cold forming, there is another suitable method that does not require the shaft body to be supported from the inside of the shaft body. The method includes forming one or more recesses in the shaft body by friction drilling.

One particular method is shown in fig. 20-23, in which a blind hole is formed in the shaft body 2. During friction drilling, the pointed hard metal heat resistant tool 600 is rotated at high speed about its axis of rotation and pressed into the outer surface 2A of the tubular wall of the shaft body 2. Due to the frictional heat, the tubular wall is locally heated and becomes flowable. In the method according to this aspect of the invention, the pointed tool 600 is not pushed completely through the tubular wall, so that a blind hole 611 is formed in the shaft body 2. The blind hole may serve as an interlock recess 11, the interlock recess 11 serving as an interlock projection formed on a trailing arm, axle pad or other clamping member that engages the axle body 2, as shown in fig. 1-6. The friction drilling can be done from the outside without the need for a backing member inside the tubular shaft body 2. Furthermore, the frictional heat is very local, whereby possible damage to the surface coating of the shaft body 2 is eliminated only at the precise location of the recess 1.

When the blind hole 611 is formed, a ridge 612 is formed on the outer surface 2A of the shaft body 2. An annular ridge 612 surrounds the blind hole and protrudes from the outer surface 2A.

As shown in fig. 21, a pattern of blind holes 611 may be formed in the shaft body 2, in this particular example, three blind holes 611 are aligned in the longitudinal direction of the shaft body 2. In fig. 27, a portion of a shaft pad 701 is shown, the shaft pad 701 having three interlocking projections 774, the interlocking projections 774 fitting in the interlocking recesses 11 constituted by the blind holes 611 in the shaft body 2. In fig. 24 and 26, it is shown in cross section and longitudinal section, respectively, how the interlock projection 774 is received in the interlock recess 11 formed by the blind hole 611. As can be seen, there is an empty space between the bottom 611A of the hole 611 and the bottom surface 774A of the projection 774. Thus, the interface between the protrusion 774 and the hole 611 is formed by the circumferential surfaces of the protrusion 774 and the hole 611 engaging with each other. The protrusions 774 and apertures 611 preferably have conical circumferential surfaces such that the interface therebetween forms a support for the axle body in the axle pad.

In fig. 25, the force F at the interface is shown that occurs when the axle pad and axle body are clamped together and the axle clamping device is subjected to torsional loading. The bottom 611A of the blind hole 611 may be within the level of the undeformed tubular wall, as shown in fig. 24. Then, the force F due to the torsional load will certainly be transmitted within the wall thickness t of the shaft body. In fig. 25 it is shown that the depth H of the hole 611 is larger than the thickness t of the tubular wall. In this case, it is desirable that the projection 774 does not extend beyond the thickness t of the tubular wall so that the force F is absorbed directly within the wall thickness of the undeformed portion of the shaft body 2.

The pedestal 701 has an annular groove 775 (see fig. 27) surrounding the projection 774, the groove 775 being adapted to receive the annular ridge 612 surrounding the blind bore 611.

During friction drilling, the heated metal is partially pushed out of the formed recess. The tool 60 has a ring ridge 61 as shown in fig. 20-23, below the ring ridge 61, a ring ridge 612 surrounding the blind hole 611 is formed of heated metal pushed upward. The tool ring ridge 61 is not suitable for cutting material. However, the annular ridge 612 may be cut by means of an annular ridge 61 on the tool 60 adapted to cut material. Another option is to cut the annular ridge 612 with a different tool. The result is shown in fig. 29, where the annular ridge 612 is removed from the outer surface of the shaft body 2.

Fig. 28 shows different patterns of the blind holes 611 and the interlocking recesses 11.

In fig. 30, a practical embodiment of a shaft body with a blind hole made by friction drilling is shown, the shaft body having a thickness t, for example 10 mm. The hole has an insertion depth H of 10mm_iI.e. the depth of the receiving protrusion. Diameter D of hole at outer surface of shaft body 2_hIs 20 mm. The outer diameter D of the shaft was 146 mm. The angle theta of the conical circumferential wall of the bore is about 20 deg..

In fig. 31A-31C, an alternative method for interlocking engagement between the axle body 2 and the axle seat 42 (see fig. 1 and 2), which in this example is a rear arm, is shown. In this method, an interlocking recess is formed in the shaft body through the shaft seat portion 42. Furthermore, the axle seat 42 is provided with an initial blind recess 43 on the outside, as shown in fig. 31A. The axle seat portion 42 is positioned against the axle body 2. Next, a friction drilling tool 62 is inserted into the initial blind recess 43 (see fig. 31B) and operated to form a deeper recess by friction drilling. In this process, the material of the shaft body 2 is also deformed, whereby the interlocking recesses 11 in the shaft body and the interlocking projections 47 in the shaft seating portion 42 are formed in one step, as shown in fig. 31C. In fig. 31C, the drilling tool is retracted from the hole being formed. Alternatively, the boring tool or a portion thereof may be fused with the metal of the gripping member 42 and retained in the bore, as shown in fig. 31D. Thereby, a stronger rotational interlocking connection is formed between the shaft body 2 and the shaft seat 42.

In fig. 33A-33C, a variation of the method is shown in which the clamping member has an initial through hole 44, and a friction drilling tool 62 is inserted into the initial through hole 44. The friction drilling tool 62 forms a blind hole or recess 11 in the shaft body 2 and is fused with the locally flowable metal of the shaft body 2 by frictional heating. Thus, the tool 62 is retained in the bore and forms an interlocking projection.

In fig. 32A-32C, an alternative method is shown. In this method, the boring tool 62 penetrates the shaft gripping member 42 and also penetrates the tubular wall of the shaft body 2, as shown in fig. 32C. In this regard, this alternative method does not fall within the claimed invention. Due to the frictional heat, the locally heated tubular wall becomes flowable, whereby the boring tool 62 may fuse with the metal of the shaft body 2 and/or the metal of the gripping member 42 and be retained in the hole.

The method as shown in fig. 31A-31D, 32A-32C, and 33A-33C allows for interlocking the shaft body 2 with at least one shaft-gripping member 42 after the shaft-gripping members 32 and 42 are mounted to the shaft body 2. Thus, the formation of the interlock recess and the interlock projection is a later step in the process of attaching the axle to the trailing arm.