Patent Description:
<CIT> shows in <FIG> a trailing arm assembly in which the trailing arm has an integrally formed air spring supporting arm which is monolithical with the attachment portion of the trailing arm and extends rearwardly therefrom via a double curved substantially crank-shaped arm portion. In <FIG> of <CIT> an embodiment is shown in which a clamping plate ("squeeze plate"), comprising an axle seat, is positioned opposite the axle pad. U-bolts squeeze the axle body between the axle pad and the clamping plate. An air spring supporting arm is integrally connected to the clamping plate. In <FIG> of <CIT> is shown an embodiment wherein the axle pad is located on an upper side of the attachment portion of the trailing arm, and wherein a squeeze plate is located on an underside of the attachment portion. An air spring supporting arm is integrally connected to this squeeze plate. The embodiments of <FIG> are horizontally seen more compact than the embodiment of <FIG>.

<CIT> discloses a trailing arm assembly wherein an axle pad is located on an upper side of an attachment portion of the trailing arm, and wherein a portion of an air spring supporting arm is located on an underside of the attachment portion of the trailing arm.

It is an object of the invention to provide an alternative trailing arm assembly.

This object is achieved by a trailing arm assembly according to the preamble of claim <NUM>, wherein the axle pad and the air spring supporting arm form an integral rear arm part.

The axle pad and the air spring supporting arm thus constitute an integral rear arm part, whilst the trailing arm constitutes a front arm part of the trailing arm assembly.

An advantage of the trailing arm assembly according to the invention is that the trailing arm itself, i.e. the front arm part, can be a more or less universal product suitable for a whole range of different wheel axle suspensions, whereas the axle pad providing the axle seat for a particular axle body and the air spring support arm (the rear arm part) can be a customized part for a specific vehicle suspension. The trailing arm is, from a manufacturing point of view, the most critical part of the trailing arm assembly. It must be able to absorb the major part of the dynamic loads during normal operation of the vehicle. The spring portion of the trailing arm is designed to be deformed and absorb the loads due to for example roll motions of the vehicle. The manufacturing of the trailing arm requires a manufacturing method performed by a specialized production facility. The trailing arm may be formed by a forging process or a rolling process. The rear arm part can be made of a different material by another manufacturing process and in different forms and sizes adapted to different vehicles.

Preferably, the integral rear arm part, constituted by the axle pad and the air spring supporting arm, is formed in one piece. A possible manufacturing method for the integral part may be forging in which a suitable steel blank is forged in preferably one stroke of the forging tool in the rear arm shape. Another method may be casting.

In another embodiment according to the invention, the axle pad and the air spring support arm are separately formed parts joined together by a permanent joint. In a practical embodiment this permanent joint between the axle pad and the air spring support arm may be formed by welding. In another embodiment, the permanent joint may be formed by riveting the axle pad and the air spring support arm together.

In yet another embodiment the axle pad and the air spring support arm are separately formed parts joined together by one or more mechanical fasteners such as bolts or screws. In this way, a non-permanent joint is formed between the axle pad and the air spring support arm.

The axle pad and the air spring support arm can be formed separately by the same or different forming processes, such as forging or casting. The air spring support arm may even be rolled or formed of metal sheet material. Forming them separately may provide more design freedom, than forming them in one piece.

In all the possible embodiments as described above, i.e. a one-piece rear arm part or a rear arm part made of a joined axle pad and air spring support arm, the axle pad and the air spring support arm constitute an integral rear arm part, which is handled as an integral part during mounting of the trailing arm assembly on the axle body.

As mentioned above the trailing arm may be a forged part. A spring steel blank is used to forge the trailing arm, preferably in one stroke of the forging tool. The trailing arm of the trailing arm assembly according to the invention may have a relatively short longitudinal length, which makes it easier to forge it with less force and less wear of forging tools and equipment.

Another option is that the trailing arm is at least partially a rolled part. In particular the elongate spring portion may be rolled to obtain the required spring characteristic. Other trailing arm portions such as the front end portion and the attachment portion may be initially rolled and then formed by an additional forming method. The front end may for example be bent into an eyelet. The attachment portion may for example be provided with bores for the bolt shanks by pressing them into the attachment portion.

In a possible embodiment the attachment portion of the trailing arm and the axle pad have interlocking means so as to interlock the trailing arm and the axle pad in a plane defined by a longitudinal direction and a transverse direction of the trailing arm. The interlocking means function as a positioning means to define the position of the trailing arm and the axle pad relative to each other. Furthermore, the interlocking means warrant that the axle pad maintains its position relative to the trailing arm when the trailing arm assembly is mounted to an axle body.

In a practical embodiment the clamping means comprise tensioning bolts, preferably U-bolts. The U-bolts extend around the axle body and the shanks of the U-bolt are tensioned with respect to the trailing arm.

The tensioning means may furthermore comprise at least one strap plate which engages the attachment portion of the trailing arm at a side opposite the axle pad, and which has bores for passing through bolt shanks of the tensioning bolts.

Alternatively or in addition, the attachment portion of the trailing arm may have a pair of ears, each ear extending laterally from the trailing arm and having a bore for passing through a bolt shank of the tensioning bolt.

In a possible embodiment the assembly has one strap plate and one pair of ears. In another possible embodiment the trailing arm is provided with two pair of ears. In yet another possible embodiment the assembly comprises two strap plates.

The invention also relates to an air sprung wheel axle suspension for a heavy vehicle such as a truck, a trailer or a semi-trailer, comprising a pair of trailing arm assemblies as described in the above, and furthermore comprising a pair of bearing brackets attached to the vehicle chassis, and an air spring supporting the vehicle chassis at a distance rearward from the bearing bracket, wherein the front end portion of the trailing arm is pivotally attached to the bearing bracket and wherein the air spring support arm is attached to a lower end of the air spring.

The invention also relates to a vehicle comprising such an air spring wheel axle suspension.

The invention will be further elucidated in the following description with reference to the drawing, in which:.

As can be best seen in <FIG>, the trailing arm assembly <NUM> comprises a trailing arm <NUM>, a rear arm part <NUM>, U-bolts <NUM> with corresponding nuts <NUM>, and strap plates 7A and 7B.

The trailing arm <NUM> has a front end portion <NUM>, an elongate spring portion <NUM> and an attachment portion <NUM>. The trailing arm <NUM> in this embodiment is a rolled part made in one piece of a spring steel blank, which has been given at least a thickness profile by means of a rolling process.

The front end portion <NUM> may be rolled initially and thereafter bent into an eyelet. In the eyelet <NUM> a bearing bushing <NUM> is arranged, also referred to as a "silentblock". The bearing bushing <NUM> comprises an inner metal bushing <NUM> and a rubber lining <NUM> on the outside of the inner metal bushing <NUM>. The rubber lining <NUM> engages the inner surface of the eyelet <NUM>. The rubber lining <NUM> has a pretension when it is arranged in the eyelet <NUM>. Some silentblocks, which may be used in the trailing arm assembly, also have an outer metal bushing, wherein the rubber layer is located between the inner and outer metal bushing.

The spring portion <NUM> is provided with a suitable thickness taper, which may be a parabolic taper, so as to obtain the suitable spring characteristics. The spring portion <NUM> is thus essentially a rolled leaf spring.

It is noted that in this embodiment the width of the spring arm portion <NUM> is essentially constant and that the thickness has a taper. However, also other shapes are possible, for example a spring arm portion having a combination of a width taper and a thickness taper. The width and thickness tapers may be parabolic or linear.

The attachment portion <NUM> of the trailing arm <NUM> has a substantially constant thickness and constant width.

The rear arm part <NUM> comprises an axle pad <NUM> and an air spring support arm <NUM> integral with the axle pad <NUM>. The axle pad <NUM> comprises a semi-cylindrical shell <NUM> that defines an axle seat <NUM> to receive a longitudinal section of the axle body <NUM>. Furthermore, the axle pad <NUM> has engagement surfaces <NUM>, <NUM> facing away from the axle seat <NUM> to engage a bottom surface 33A of the attachment portion <NUM> of the trailing arm <NUM>. On the engagement surface <NUM> a positioning protrusion <NUM> is formed, which is to be received in a positioning recess (not visible) in the bottom side 33A of the attachment portion <NUM> of the trailing arm <NUM>. The positioning protrusion <NUM> provides a well-defined positioning of the axle pad <NUM> with respect to the trailing arm <NUM>, but it also results in that the axle pad and the trailing arm <NUM> interlock in the longitudinal and transversal direction of the trailing arm <NUM>.

An option to fix the axle pad and block mutual rotation of the axle body and the axle pad is to weld the axle pad on the axle body.

The rear arm part if formed in one piece. The air spring support arm <NUM> is monolithical with the axle pad <NUM>. The rear arm part <NUM> may be formed by forging or casting.

The U-shaped bolts <NUM> extend around the axle body <NUM> and the shanks <NUM> of the U-shaped bolts <NUM> extend along lateral sides of the attachment portion <NUM> of the trailing arm <NUM>.

The strap plates 7A, 7B extend in a width direction over a top side of the attachment portion <NUM> of the trailing arm <NUM>. The strap plates 7A, 7B have end portions <NUM> that extend beyond the lateral sides of the attachment portion <NUM> of the trailing arm. The end portions <NUM> have a bore <NUM> through which one of the shanks <NUM> of the corresponding U-bolt <NUM> is passed. The strap plates 7A, 7B have an upper surface that serves as a counter surface for the respective nuts <NUM>, which are cooperating with the threaded portion of the respective shanks <NUM>.

The trailing arm assembly <NUM> can be attached to the axle body <NUM> by arranging the axle pad <NUM> with the engagement surfaces <NUM>, <NUM> against the bottom side 33A of the attachment portion <NUM> of the trailing arm <NUM> and by positioning the axle body <NUM> in the axle seat <NUM> provided by the axle pad <NUM>. The U-bolts <NUM> are arranged around the axle body <NUM> and the shanks <NUM> of each of the U-bolts <NUM> extend along one of the lateral sides of the attachment portion <NUM> of the trailing arm <NUM>. The strap plates 7A, 7B are arranged on the top side of the attachment portion <NUM> of the trailing arm <NUM>. The shanks <NUM> extend through the bores <NUM> in the strap plate 7A, 7B and the nuts <NUM> are screwed on the shanks <NUM>. By tightening the nuts <NUM> the shanks <NUM> are tensioned, whereby the attachment portion <NUM> of the trailing arm <NUM>, the axle pad <NUM> and the axle body <NUM> are clamped together to form a rigid unit. In this embodiment, the clamping means of the trailing arm assembly are thus constituted by the U-bolts <NUM>, the corresponding nuts <NUM> and the strap plates 7A, 7B.

In the embodiment of <FIG>, the strap plates 7A and 7B are two separate strap plates. It is however also conceivable that the strap plates are formed as one unit, which is as such known in the art. It is also possible that only one strap plate <NUM> is used and that at the attachment portion of the trailing arm <NUM> a pair of ears <NUM> with a bore for the shanks of the U-bolts is formed as is shown in the embodiment of <FIG>. It is also conceivable that the attachment portion of the trailing arm has two pairs of ears <NUM>, <NUM> having a bore formed on it as is shown in the embodiment of <FIG>, in which embodiment the strap plates can be omitted.

The trailing arm assembly <NUM>, which is attached to the axle body <NUM>, can be mounted to a vehicle chassis as is shown in <FIG> to form an air sprung wheel axle suspension of the vehicle. The vehicle may typically be a semi-trailer, a trailer or a truck. As the skilled person will understand there are two suspension units as shown in <FIG> attached to each axle body <NUM>, one at each lateral side of the chassis.

The air-sprung wheel axle suspension thus has a bearing bracket <NUM> on either lateral side of the vehicle chassis, which bearing bracket <NUM> is attached to an overhead chassis beam <NUM>. The front end portion <NUM> of the trailing arm <NUM> is arranged between lateral plates <NUM> of the bearing bracket <NUM> such that the ends of the metal bushing <NUM> engage the inner side of the lateral plates <NUM>. A pivot bolt <NUM> is inserted through a bore in the lateral plates <NUM> and through the bushing <NUM> in the eyelet <NUM> of the trailing arm <NUM>. By tightening the pivot bolt <NUM> by means of a corresponding nut (not shown), a pivoting connection between the bearing bracket <NUM> and the front end portion <NUM> of the trailing arm <NUM> is established.

An air spring <NUM> is positioned between the chassis and the trailing arm assembly <NUM>. The air spring <NUM> has a lower end, which is attached to the air spring support arm <NUM>. An upper end of the air spring <NUM> supports the chassis, wherein the upper end of the air spring <NUM> may be attached to the chassis beam <NUM>.

In the embodiment shown in <FIG> the suspension furthermore comprises a shock absorber <NUM> which is pivotally connected to the bearing bracket <NUM> and with an opposite end pivotally connected to the front strap plate 7A, which strap plate 7A has two mounting ears <NUM> for connecting the shock absorber <NUM> to.

With reference to the <FIG>, another embodiment of a trailing arm assembly according to the invention is described.

<FIG> show a trailing arm assembly <NUM>. The trailing arm assembly <NUM> is attached to an axle body <NUM>, in this case a tubular axle body <NUM> having a circular cross section. The attachment of the trailing arm assembly <NUM> to the axle body <NUM> takes place by a clamping arrangement.

As can be best seen in <FIG>, the trailing arm assembly <NUM> comprises a trailing arm <NUM>, a rear arm part <NUM>, U-bolts <NUM> with corresponding nuts <NUM>, and a strap plate <NUM>.

The trailing arm <NUM> has a front end portion <NUM>, an elongate spring portion <NUM> and an attachment portion <NUM>. The trailing arm <NUM> in this embodiment is a forged part made in one piece of a spring steel blank.

The front end portion <NUM> of the trailing arm <NUM> comprises a half eyelet, which can form an eyelet with an opposite separate eyelet part <NUM> clamped on the front end part <NUM> of the trailing arm <NUM> by means of a U-bolt <NUM>. A bearing bushing <NUM> (a silentblock) having an inner metal bushing <NUM> and an outer rubber layer <NUM> is clamped on the front end part <NUM> of the trailing arm <NUM> by means of a U-bolt <NUM> and the separate eyelet part <NUM>.

The spring portion <NUM> has a channel shaped profile that is open at a bottom side, as can be best seen in <FIG> and <FIG> and in the cross section of <FIG>. The channel shaped profile has a top wall <NUM> and lateral walls <NUM>. In general, the channel shaped profile has a U-shaped cross section.

The lateral walls <NUM> have a proximal end that is connected to the top wall <NUM>. Furthermore, the lateral walls <NUM> have a distal end at the open side of the channel profile. Thickened portions are formed at the distal end of the lateral walls <NUM>. The thickened portions protrude outwardly with respect to the outer surface of the lateral walls <NUM> and thereby form lateral ridges <NUM>.

The height of the spring portion <NUM> increases from the front end portion <NUM> towards the attachment portion <NUM>. The attachment portion <NUM> has a channel shaped profile that is open at a bottom side and is an extension of the spring portion <NUM>. The attachment portion <NUM> has in this example a substantially constant height. At the rear end of the attachment portion <NUM>, a laterally extending ear <NUM> is formed at each lateral side. The ears <NUM> have a bore <NUM> for passing through the shanks of the U-bolts <NUM>.

The rear arm part <NUM> comprises an axle pad <NUM> and an air spring support arm <NUM> integral with the axle pad <NUM>. The axle pad <NUM> comprises a semi-cylindrical shell <NUM>, which defines an axle seat <NUM> to receive a longitudinal section of the axle body <NUM>. Furthermore, the axle pad <NUM> has engagement surfaces <NUM>, <NUM> on the side of the axle pad <NUM> facing away from the axle seat <NUM> to engage corresponding surfaces of the attachment portion <NUM> of the trailing arm <NUM>.

On the engagement surface <NUM> a pair of positioning protrusions <NUM> is formed, which is to be received in the channel space of the attachment portion <NUM> of the trailing arm <NUM>. The protrusions <NUM> engage the inner side of the lateral walls of the channel shaped attachment portion <NUM>. The positioning protrusions <NUM> results in that the axle pad <NUM> and the trailing arm <NUM> interlock in the transversal direction of the trailing arm <NUM>.

The engagement surface <NUM> is formed as a conical surface of a truncated cone formed on an upper side of the axle pad <NUM>. At a rear end of the attachment portion <NUM> of the trailing arm <NUM>, a conical recess <NUM> is formed in the underside of the attachment portion <NUM>. The truncated cone, having the engagement surface <NUM>, is received in the conical recess <NUM> when the axle pad is positioned against the attachment portion <NUM> of the trailing arm <NUM>, as is best visible in <FIG>. The truncated cone and the recess <NUM> form another interlocking feature between the trailing arm and the axle pad <NUM>, which interlocks them in the longitudinal and lateral direction of the trailing arm <NUM>.

The air spring support arm <NUM> is monolithical with the axle pad <NUM>. The air spring support arm <NUM> in this embodiment has a sort of channel profile shape having a height decreasing from the axle pad <NUM> towards the rear.

The rear arm part <NUM> may be formed by forging or casting.

The trailing arm assembly <NUM> can be attached to the axle body <NUM> by arranging the axle pad <NUM> with the engagement surfaces <NUM>, <NUM> against the engagement surfaces of the attachment portion <NUM> of the trailing arm <NUM> and by positioning the axle body <NUM> in the axle seat <NUM> provided by the axle pad <NUM>. The U-bolts <NUM> are arranged around the axle body <NUM> and the front shanks 51A of each of the U-bolts <NUM> extend along one of the lateral sides of the attachment portion <NUM> of the trailing arm <NUM>.

A strap plate <NUM> is arranged on the attachment portion <NUM> of the trailing arm <NUM> and rests at least on the lateral ridges 138A of the attachment portion <NUM>. The front shanks 51A extend through the bores in the strap plate <NUM>. The rear shanks 51B extend through the bores <NUM> in the ears <NUM>. Nuts <NUM> are screwed on the shanks 51A, 51B. By tightening the nuts <NUM> the shanks 51A, 51B are tensioned, whereby the attachment portion <NUM> of the trailing arm <NUM>, the axle pad <NUM> and the axle body <NUM> are clamped together to form a rigid unit. In this embodiment, the clamping means of the trailing arm assembly <NUM> are thus constituted by the U-bolts <NUM>, the corresponding nuts <NUM> and the strap plates <NUM>.

The trailing arm assembly <NUM>, which is attached to the axle body <NUM>, can be mounted to a vehicle chassis as is shown in <FIG> to form an air sprung wheel axle suspension of the vehicle, which vehicle typically is a semi-trailer, a trailer or a truck. As the skilled person will understand there are two suspension units as shown in <FIG> attached to each axle body <NUM>, one at each lateral side of the chassis.

The air-sprung wheel axle suspension comprises thus on either lateral side of the vehicle chassis a bearing bracket <NUM> which is attached to an overhead chassis beam <NUM>. The front end portion <NUM> is arranged between lateral plates <NUM> of the bearing bracket <NUM> such that the ends of the inner metal bushing of the silentblock <NUM> engage the inner side of the lateral plates <NUM>. A pivot bolt <NUM> is inserted through a bore in the lateral plates <NUM> and through the bushing (silentblock) <NUM> mounted to the front end portion <NUM> of the trailing arm <NUM> by the U-bolt <NUM>. By tightening the pivot bolt <NUM> by means of a corresponding nut (not shown), a pivoting connection between the bearing bracket <NUM> and the front end portion <NUM> of the trailing arm <NUM> is established.

An air spring <NUM> is positioned between the chassis and the trailing arm assembly <NUM>. The air spring <NUM> has a lower end which is is attached to the air spring support arm <NUM>. An upper end of the air spring <NUM> supports the chassis, wherein the upper end of the air spring <NUM> may be attached to the chassis beam <NUM>.

In the embodiment shown in <FIG> the suspension furthermore comprises a shock absorber <NUM>, which is pivotally connected to the bearing bracket <NUM> and with an opposite end pivotally connected to the strap plate <NUM>, which strap plate <NUM> has two mounting ears <NUM> for connecting the shock absorber <NUM>.

It is noted that, although the embodiments described in the above have eyelets or eyelet-like constructions at the front end portion of the trailing arm <NUM>, <NUM>, it is within the scope of the claimed invention to provide other pivoting structures to connect the front end portion pivotally to the bearing bracket. The front end portion may for example be formed having journaling pins, which provide the front end portion with a sort of hammerhead shape. These journaling pins can be received in corresponding recesses in the bearing bracket. Such a pivoting structure is disclosed in <CIT>.

In <FIG> is shown a trailing arm assembly <NUM> of the so-called "underslung" type, i.e. the trailing arm <NUM> and axle pad <NUM> are arranged underneath the axle body <NUM>. Such an embodiment is also encompassed to be within the scope of the claimed invention.

In the embodiments shown in <FIG>, the rear arm part is formed in one piece, e.g. by forging or casting. It is however also conceivable that the rear arm part is assembled from an initially separately formed axle pad and air spring support arm. The axle pad and air spring support arm can be joined by a permanent or non-permanent joint to form the integral rear arm part. In <FIG> two examples are shown.

In <FIG> is shown a trailing arm assembly <NUM> in which the axle pad <NUM> and the air spring support arm <NUM> are formed initially as separate parts, e.g. by forging or casting, and wherein the axle pad <NUM> and the air spring support arm <NUM> are attached to each other by a welded joint <NUM> to form the integral rear arm part <NUM>. The rest of the parts of the trailing arm assembly <NUM> may be the same as in the embodiment of <FIG> for example, so referral is made to the description of the embodiment of <FIG> for the other parts.

In <FIG> is shown a trailing arm assembly <NUM> in which the axle pad <NUM> and the air spring support arm <NUM> are formed initially as separate parts, e.g. by forging or casting, and wherein the axle pad <NUM> and the air spring support arm <NUM> are attached to each other by a mechanical joint, in this example by a bolted connection <NUM>, to form the integral rear arm part <NUM>. Again, the rest of the parts of the trailing arm assembly <NUM> may be the same as in the embodiment of <FIG> for example, so referral is made to the description of the embodiment of <FIG> for the other parts.

In the embodiments of <FIG> the axle pad <NUM>, <NUM> and the air spring support arm <NUM>, <NUM> constitute an integral rear arm part <NUM>, <NUM> which is handled as an integral part during mounting of the trailing arm assembly <NUM>, <NUM> on the axle body <NUM>.

Summarizing, the invention proposes a trailing arm assembly <NUM>, <NUM>, <NUM>, <NUM>, <NUM> having a two-part arm having a front arm part <NUM>, <NUM>, <NUM> and a rear arm part <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. The front arm part <NUM>, <NUM>, <NUM> is a flexible trailing arm made of spring steel. The rear arm part <NUM>, <NUM>, <NUM>, <NUM>, <NUM> integrates the function of an axle pad <NUM>, <NUM>, <NUM> and an air spring support arm in one integral part. The axle pad <NUM>, <NUM>, <NUM>, <NUM>, <NUM> is adapted to be clamped between an attachment portion <NUM>, <NUM>, <NUM> of the trailing arm <NUM>, <NUM>, <NUM> and an axle body <NUM> by suitable clamping means comprising for example U-bolts <NUM> or other tensioning bolts. The air spring support arm <NUM>, <NUM>, <NUM>, <NUM>, <NUM> is connected to a rear end of the axle pad <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and extends rearwardly from the axle pad <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. The rear arm part <NUM>, <NUM>, <NUM> is preferably formed in one piece, e.g. by forging or casting. However, rear arm parts <NUM>, <NUM>, which are initially formed in two or more pieces, and joined by welding or bolting, or another suitable permanent or non-permanent joint are conceivable.

Claim 1:
Trailing arm assembly (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) for an air sprung wheel axle suspension, comprising
- a trailing arm (<NUM>, <NUM>, <NUM>) having a front end portion (<NUM>, <NUM>) adapted to be pivotally arranged in a bearing bracket (<NUM>) of a vehicle chassis, an attachment portion (<NUM>, <NUM>) adapted to attach an axle body (<NUM>) to the trailing arm (<NUM>, <NUM>), and a spring portion (<NUM>, <NUM>) between the front end portion (<NUM>, <NUM>) and the attachment portion (<NUM>, <NUM>),
- an axle pad (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) adapted to be arranged between the attachment portion (<NUM>, <NUM>) of the trailing arm (<NUM>, <NUM>, <NUM>) and the axle body (<NUM>), the axle pad (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) defining an axle seat to receive a longitudinal portion of the axle body (<NUM>),
- clamping means (<NUM>, <NUM>, <NUM>) adapted to engage the axle body (<NUM>) and to engage the trailing arm (<NUM>, <NUM>) so as to clamp the axle body (<NUM>), the axle pad (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) and the attachment portion (<NUM>, <NUM>) of the trailing arm (<NUM>, <NUM>) together,
- an air spring support arm (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) for attaching an air spring (<NUM>), which air spring (<NUM>) is located between the support arm (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) and the chassis,
characterized in that the axle pad (<NUM>, <NUM>,<NUM>, <NUM>, <NUM>) and the air spring support arm (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) form an integral rear arm part (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>).