WO1982002172A1

WO1982002172A1 - Arrangement for mounting a leaf spring assembly forming part of a vehicle suspension

Info

Publication number: WO1982002172A1
Application number: PCT/SE1981/000384
Authority: WO
Inventors: Scania Ab Saab
Original assignee: Johansson Gustav Arne; Nordstroem Mauritz; Sjoestroem Staffan Sverkerson
Priority date: 1980-12-22
Filing date: 1981-12-21
Publication date: 1982-07-08
Also published as: HU190787B; GB2101269B; GB2101269A; SE8009050L; DE3152653A1; SE434623B

Abstract

Arrangement for mounting a leaf spring assembly (3) forming part of a vehicle suspension and connecting at least one wheel axle bracket (2) or similar device with the frame of the vehicle. An end section (13) of the leaf spring assembly (3) is secured to either wheel axle bracket (2) or to the vehicle frame and the invention is intended to provide an adjustable mounting meeting the requirements in respect of freedom from maintenance and good noise and vibration damping while at the same time enabling simple adjustment of the position of the wheel axle bracket (2) in relation to the vehicle frame. With the above aim the end section (13) of leaf spring assembly (3) is provided with an arc-shaped surface which, via a bush (25) consisting of an non-metallic material, co-operates with a corresponding arc-shaped inner surface in a bearing housing (11, 12) encircling an end section (13). The bearing housing consists of two loose bearing halves (11, 12) capable of being secured to one another and the bearing housing is adjustably attached to a retaining part (15) of the wheel axle bracket (2) or the vehicle frame, thus reducing the danger of abnormal tyre wear.

Description

Arrangement for mounting a leaf spring assembly forming part of a vehicle suspension

The present invention relates to an arrangement for mounting a leaf spring assembly forming part of a vehicle suspersion and connecting at least one wheel axle bracket or similar device with the frame of the vehicle, whereby at least one end section of the leaf spring assembly is secured to the wheel axles bracket or vehicle frame.

It is generally known how to support such an end section of a leaf spring assembly with the aid of a shackle pin firmly attached to the vehicle frame, thereby shaping the outer end of the longest leaf in the spring assembly so as to form an eye which encircles the shackle pin via a steel bush. Regular lubrication and maintenance is required for such a construction to operate in a satisfactory manner. However, from the point of view of comfort this design is subject to the disadvantage that it transmits noise and vibrations from the main axle to the vehicle chassis and to any driver's cab mounted thereon. With a view to eliminating the said disadvantages it is known how, with an arrangement such as initially described, to support the end section of the leaf spring assembly in an elastic bush, which in turn is encircled by a bearing housing holding the bearing together. It is however difficult and time-consuming to mount such known bearings on the wheel bearing bracket or vehicle frame, while in addition presupposing great accuracy, especially if the wheel axle bracket suspended with the aid of the leaf spring assembly is to be given a position which from the point of view of tyre wear is advantageous.

The present invention is intended to enable, with an arrangement of the type initially described, a leaf spring attachment not requiring any maintenance and insulated against noise and vibrations which also enables simple adjustment of the wheel axle bracket in respect of the vehicle frame. The end section of the leaf spring assembly is, according to the invention, provided with an arc-sharped outer surface, which, via a bush of a non-metallic material, co-operates with a corresponding arc-shaped inner surface within bearing housing enclosing the end section, whereby the invention is characterised in that the bearing housing consists of two loose bearing halves capable of being secured to one another and in that the bearing housing is adjustably secured to a retaining part of the wheel axle bracket or vehicle frame.

The arrangement according to the invention is such that when power is transmitted between the end section of the spring assembly and the bearing housing the intermediate bush is subjected to a load evenly distributed over a relatively large area, irrespective of the relative angular position between the end section and the bearing housing. By providing a bush of non-metallic material a maintenancefree mounting is achieved, with good noise-damping characteristics. Inasmuch as the bearing housing consists of two loose bearing housing halves it is possible for the bearing housing to be adjusted in relation to the wheel axle, in the longitudinal direction of the vehicle. The said adjustability enables simple correction of any inclination of the main axle in relation to the vehicle frame and reduces the danger of abnormal tyre wear due to this cause.

With an advantageous embodiment the bush is made of an elastic material, preferably a rubber material. As a result a maintenancefree mounting is achieved at low cost, with the rubber bush at the same time meeting stringen requirements of vibration clamping between the wheel axle and the vehicle frame.

Other characteristic features of the invention will be found in the description below and in the subsequent patent claims. The description of an embodiment illustrating the invention is given with reference to the attached figures, of which Figure 1 shows a vertical cross-section through a specimen mounting in the longitudinal direction of the spring assembly, and

Figure 2 shows a cross-section A-A through the mounting in accordance with figure 1. An end mounting 1 shown in figure 1 of a spring assembly 3 is attached to an axle bracket 2 forming part of a two-axle bogie construction for heavy trucks. The spring assembly 3 comprises at least three spring leaves 4-6, playing an active role in the transmission of forces between axle bracket 2 and the vehicle frame (not illustrated). The centre section of the spring assembly (not illustrated) transmits in a manner known with bogie constructions forces from a supporting axle (not illustrated) which is secured to the vehicle frame. The spring assembly 3 is also intended to transmit between the vehicle frame and the wheel axles such forces as arise in the longitudinal direction of the vehicle, for instance during acceleration and deceleration of the vehicle.

A two-part bearing housing consisting of an upper housing half 11 and a lower housing half 12 encloses end section 13 of spring assembly 3. The bearing housing is secured, with the aid of four screws 14, from below to a retaining part 15 attached to axle bracket 2 by welding. The upper housing half 11 and the retaining part 15 have mutually opposite abutment faces 16, as a result of which the upper housing half 11 is clamped fast between the retaining part 15 and the lower housing half 12 when the screws 14 are tightehend. In addition two smaller screws 18,19 ensure that the two housing halves 11,12 are secured to one another (see figure 2). One of the screws, 18, thereby passes through a clearance hole in the lower housing half 12 and is threaded in the upper housing half 11, whereas, in reverse manner, the other screw 19 passes through a clearance hole in the upper housing half 11 and is threaded in the lower housing half 12. This enables identical design of the respective housing halves 11,12. The play in the clearance hole facilitates mutual attachment of the housing halves 11,12 with the end section 13 of the spring assembly mounted in between whenever the spring assembly 3 is an unloaded condition. This play also enables adjustment of the position of housing ha lves 11,12 in relation to one another, even after the spring assembly 3 has been subjected to some loading. The screws 14 have some play in the clearance holes provided in the respective housing halves 11,12, with screws 18,19 having play only in the clearance holes provided in either housing half 11,12. On ce the screws 14 are released it is possible to adjust the position of the end mounting 1 in respect of axle bracket; 2 in the longitudinal direction of the vehicle. This is done with the aid of two adjusting screws 20, one on either side of axle bracket 2. Either adjusting screw 20 is threaded in the retaining part 15 and abuts with its inner end. lug 21 forming part of housing half 11. By adjusting the axial position of the screws any inclination of the end mounting 1 can be readily corrected. The spring assembly 3 is supported in housing 11,12 with the add of a bush 25 located between the housing halves 11,12, the said bush being so arranged as to transmit forces between end section 13 of the spring assembly and the housing 11,12. The upper and the lower spring leaf 4,6 of spring assembly 3 are, at their respective ends, provided with a substantially semicylindrical outward facing arc 27 or 28, respectively. Between the outer spring leaves 4 , 6 with the arcs 27; 28 facing in opposite directions there extends an intermediate spring leaf 5, the end section of which is straight and which serves as a support for the arc-shaped outer ends 27,28 of the outer spring. leaves 4 ,6. The arcs abut with their respective outsides the inside of bush 25, the outer surface of which abuts the insides of the substantially semicylindrical housing halves 11,12. In a lateral direction bush 25 extends around and past the respective edges of the spring leaves (see figure 2), as a result of which bush 25 can efficiently transmit forces between the spring assembly 3 and the axle bracket 2, even with inclining movements and laterally directed forces between the wheel axle and the vehicle frame.

The housing halves 11,12 are provided with an opening for introducing the spring leaves 4-6 into housing 11,12 the said opening being advantageously so designed as to correspond to a certain predetermined angular movement of the spring leaves 4-6. Diametrally opposite the said opening the housing halves 11,12 are so designed as to form jointly an inner pocket 29 into which fits a projection 26 of bush 25, the purpose of which is to prevent turning of the bush 25 in relation to arcs 27,28 and housing halves 11, 12. With an advantageous embodiment the bush 25 is made of an elastic rubber material, which with the bush 25 in its mounted position is firmly compressed between the said surfaces. When the spring leaf assembly 3 is bent and the end section 13 is turned relative to housing 11,12 the rubber material is subject to shear. whereas during transmission of vertical and horizontal forces rubber material in bush 25 is compressed between the arc-shaped end sections 27,28 of the springs and the housing 11,12. The vibration damping characteristics of the rubber material substantially prevent transmission of noise and vibrations to the driver's cab of the vehicle.

Within the scope of the subsequent patent claims the invention can be modified in different embodiments. It is for instance possible to make the bush 25 of a plastic material with high tensile strength and also the arc shape of the two outer spring leaves 4,6 in the end section of the spring assembly 3 can be varied within wide limits.

Nor is it necessarily required for the said arc shape to be identical with the inner surface of bearing housing 11,12, but may very well be somewhat different.

The arc-shaped outer surface of the end section may possibly be brought about without bending of the outer end sections of the leaf springs. This is achieved with the aid of one or several separate bearing blocks locked by means of one or several control pins to the end section of the leaf spring assembly, thereby forming the arc-shaped end section of the leaf spring assembly for mounting, via a bush 25, in bearing housing 11,12.

Claims

C L A I M S

1. An arrangement for mounting a leaf spring assembly (3) forming part of a vehicle suspension and connecting at least one wheel axle bracket (2) or similar device with the frame of the vehicle, whereby at least one end section (13) of the leaf spring assembly (3) is secured to either wheel axle bracket (2) or the vehicle frame, the said end section (13) being provided with an arc-shaped outer surface which, via a bush (25) consisting of a non-metallic material, cooperates with a corresponding arc-shaped inner surface of a bearing housing (11,12) encircling the end section (13), c har ac t e ri s e d in that the bearing housing consists of two loose bearing halves (11,12) capable of being attached to one another and in that the bearing housing (11,12) is adjustably secured to a retaining part (15) of the wheel axle bracket (2) or the vehicle frame¬

2. An arrangement in accordance with claim 1, c har ac t eri s e d in that the bush (25) is made of an elastic non-metallic material, preferably a rubber material.

3. An arrangement in accordance with claim 2, ch arac t eri s e d in that the bush (25) is provided with a projection (26) which engages a pocket (29) or similar device in the bearing housing (11,12).

4. An arrangement in accordance with any of the above claims, c h a r a c t e r i s e d in that the outer surface of end section (13) consists of a substantially cylindrical surface formed by at least one spring leaf (4,6).

5. An arrangement in accordance with any of claims 1-3. c h a r a c t e r i s e d in that the outer surface of end section (13) substantially consists of two semi cylindrical bearing blocks immovably secured to the end section.

6. An arrangement in accordance with claim 1, c h a r a c t e r¬i s e d in that the two halves of the bearing housing (11,12) are substantially identical.