The present invention relates to an anti roll bar connecting a driver's cabin to a vehicle's frame. According to the prior art the anti roll bar comprises at least one torsion bar and two arms, each releasably connected to each of the ends of the torsion bar.

In traditional versions of anti roll bars it is necessary to dismantle the whole anti roll bar if, for example, the radiator needs to be removed for cleaning, or if it is necessary to replace the anti roll bar's bearing units. This will require the use of a transverse crane for suspension of the driver' s cabin. This is an extremely cumbersome and expensive solution.

In light of this, a need has arisen for anti roll bars which are designed with modular solutions.

It is an object of the present invention to provide a solution where parts of the anti roll bar such as the torsion bar or the bearings can be dismantled (and possibly also mounted) without the need to remove the whole anti roll bar from the vehicle.

Modular solutions exist today, but they are expensive and require a great deal of space. SE 523 939 discloses an example of a modular solution, where the anti roll bar's torsion bar can be released from the anti roll bar's arms while the anti roll bar is located in the vehicle. The solution presented in SE 523 939 is expensive to manufacture and in addition this solution does not offer the possibility of replacing the bearings while the anti roll bar is in the vehicle. When employing a solution like that in SE 523 939, therefore, it is necessary to dismantle the whole anti roll bar if there is a need to replace a bearing.

It is a further object of the present invention to provide a modular-based anti roll bar which is compact and reasonably-priced and where it is possible to replace the bearings without dismantling the whole anti roll bar from the vehicle.

The above objects are achieved by the invention as specified in the independent patent claim. Embodiments of the invention are indicated in the dependent patent claims. An anti roll bar according to the invention is provided by each of the anti roll bar's arms being fixed to the torsion bar by means of at least one attachment device which is positioned in a through-going passage in each arm. The attachment device's end portion is housed in a bore in the torsion bar.

According to a preferred embodiment of the invention each attachment device is arranged in a releasable manner. The torsion bar's bore may be provided with threads, thus enabling the attachment device to be screwed into the bore, or the

attachment device to be secured with its end portion housed in the torsion bar's bore in another way. If it is desirable to dismantle the torsion bar or one of the anti roll bar's bearings, the attachment device's end portion is withdrawn from the torsion bar's bore. With the attachment device in this position, the torsion bar can be released from the anti roll bar while the remaining parts are left on the vehicle.

Instead of using slide or roller bearings, elastic bearings may be employed in the anti roll bar. The anti roll bar may have two elastic bearings, each elastic bearing being mounted in a bearing space in each arm. The attachment device extends through a bore provided in the elastic bearing and secures the elastic bearing in position in the bearing space. In an embodiment use may be made of an intermediate structure which is arranged coaxially round the attachment device, a portion of the intermediate structure being mounted between the elastic bearing and the attachment device. In a preferred embodiment the elastic bearing has a sleeve- like shape, where the bearing wall is in the form of an external curved surface preferably with a convex or concave shape. The bearing wall's curved shape is provided by the design of the elastic bearing. The fact that the elastic bearing is curved in shape allows both axial and radial forces to be absorbed.

In an embodiment of the elastic bearing, the internal surface of the elastic bearing is attached to the external surface of a first rigid inlay. The external surface of the elastic bearing is attached to the internal surface of a second rigid inlay. The first rigid inlay's remaining surfaces may be covered by an internal layer of elastic material and an external layer of elastic material may be attached to the second rigid inlay's external surface. An external layer of elastic material is attached to the second rigid inlay's external surface. The external layer of elastic material may be tolerance-absorbent.

The arm's bearing space may be designed with an open side for insertion and removal of the rubber bearing. Furthermore, suitable attachment means are employed to ensure that the elastic bearing is fixed to the vehicle's frame. The driver's cabin may be connected to the arm by a spring unit, one end of which is fixed to the driver's cabin and the other end is fixed to the attachment device or to the intermediate structure by suitable means.

The attachment device's centre axis may be coincident or parallel with the torsion bar's centre axis, and the attachment device may be composed of a centre bolt. The intermediate structure may be composed of a centre sleeve. In the transition between the torsion bar and each arm, torque-transferring devices may be provided which are capable of absorbing torque. The torque-transferring devices may be composed of balls, cylinders, pins or other structures suited for transferring torque. The torque-transferring devices may be connected to the torsion bar and the arm in various ways. In a preferred embodiment of the invention each

end of the torsion bar and each arm are provided with seats, preferably grooves suitable for accepting the torque-transferring devices. The seats may be plastically deformed when mounting the arm to the torsion bar, and the torque-transferring devices may be provided in tolerance-absorbent form. The elastic bearing's elasticity makes it possible to release the torque-transferring devices from the set of grooves provided in the torsion bar or the set of grooves provided in the arm when the torsion bar has to be dismantled from the anti roll bar . Suitable means or arrangements ensure that the torque-transferring devices are secured to the torsion bar's set of grooves or the arms' set of grooves when dismantling the torsion bar, thus preventing the torque-transferring devices from falling out.

In one embodiment at least a recess and at least an embossed section which fit together are provided for the connection of the torsion bar and each of the arms. The recess(es) may be provided at the end of the arm and the embossed section at the end of torsion bar, or the recess(es) may be provided at the end of the torsion bar and the embossed section(s) at the end of the arm. The grooves may be situated in the recess and in the embossed section. When each arm is connected to the torsion bar, each torque-transferring device is secured in one of the grooves provided in the recess or embossed section, and received in one of the grooves provided in other of the embossed section or recess, so that the split line between each arm and torsion bar correspond to the centre lines of the torque-transferring devices.

Each torque-transferring device may be secured in each groove by local deformation.

When the torque-transferring devices are secured in the grooves of the recess, local deformation of at least one portion of the recess close to the torque-transferring device may be performed, thereby bending off set material over each of the torque- transferring device. The grooves of the embossed receive each torque-transferring device and is shaped adjusting for the local deformation carried out for the torque- transferring devices in the grooves of the recess.

When the torque-transferring devices are secured in the grooves of the embossed section, the shape of the opening of each of the recess might make sure that the torque-transferring devices are kept within the grooves. Alternatively, local "t^formation may be performed to secure the torque-transferring devices in the grooves, by bending off set material over each of the torque-transferring device.

As the slcϊifled person will understand a various numbers of recesses and embossed sections may* be provided. In one embodiment one recess and one embossed section are arranged to fn\ together. In an alternative embodiment two embossed sections are brought about by form ing two recesses either in the arm or in the torsion bar, wherein the torque-transKarring devices may be secured in grooves performed in the recess in between these two Embossed sections, using local deformation if necessary

to keep the torque-transferring devices in the grooves. The other of the arm or the torsion bar may be provided accordingly to fit with the arrangements of the two embossed sections.

In one embodiment the elastic bearing is provided so that it is prevented from rotating. This may be carried out by providing the external layer so that the elastic bearing is prevented from rotating, preferably by shaping the cross section of the external layer non circular or providing the external layer with at least one locking element which is secured to a corresponding part of the vehicle.

The concept of employing torque-transferring devices housed in grooves in two components that have to be interconnected as described above, where the grooves are at least partly plastically deformed, may also have other applications than for joining an arm to a torsion bar. The concept can be utilised within all areas of application where forces or torque require to be transferred between two components. If the torsion bar has to be dismantled, the attachment device is withdrawn from the torsion bar's bore and the torsion bar is then removed. The elasticity in the elastic bearing permits the torque-transferring devices to be released from one of the set of grooves, where the torque-transferring devices can be secured, for example to the torsion bar, to the arm or the arm and the torsion bar alternately. If the torsion bar has to be mounted on to the anti roll bar, the torsion bar is positioned in a manner that enables the attachment device to be moved into engagement with the torsion bar's bore.

If the elastic bearing has to be dismantled from the anti roll bar while the anti roll bar is located in the vehicle, the attachment device is withdrawn from the torsion bar's bore, whereupon the attachment device and possibly the intermediate structure are withdrawn from the bore in the arm and the elastic bearing is free to be ejected through the bearing space's side opening. If the elastic bearing has to be mounted in the anti roll bar, the elastic bearing is inserted through the side opening of the space. The elastic bearing is positioned in a manner that enables the attachment device and possibly the intermediate structure to be inserted through the elastic bearing's bore and the attachment device is moved on to engage with the torsion bar's bore.

An example of an embodiment of the invention will now be described with reference to the figures, in which Fig. 1 is a plan sectional view of a anti roll bar according to the invention viewed from above.

Fig. 2 illustrates a section of fig. 1. Fig. 3 illustrates an elastic bearing to be employed in the anti roll bar as illustrated

in figs. 1 and 2.

Figs. 4a and 4b illustrate the seats for the torque-transferring devices before and after mounting.

Fig. 1 illustrates a anti roll bar 1 for a driver's cabin preferably belonging to a lorry. The anti roll bar 1 comprises two arms, each attached to a torsion bar 2. The longitudinal dimension of the torsion bar 2, illustrated here by arrow T, coincides with the vehicle's transverse direction, while the arms' 3 longitudinal dimension, illustrated here by arrow A, coincides with the vehicle's longitudinal direction. In fig. 1 only a portion of the anti roll bar 1 is shown. It can be seen in fig. 1 that the arm 3 is attached to the torsion bar 2 at one of its end portions 3a by means of an attachment device 4, illustrated here in the form of a bolt. The attachment device 4 is positioned in the arm's passage 7 and the attachment device's end portion 4a is mounted in a bore 8 in the torsion bar 2 for attachment of the arm 3 to the torsion bar 2. It can be seen in fig. 1 that an intermediate structure in the form of a centring sleeve 9 is mounted coaxially about the attachment device in the passage 7 and that the passage is provided with a diametrical extension 10 which is adapted to the diameter of the centring sleeve 9. The centring sleeve 9 is provided with a portion 9a which is in abutment against the arm's lateral surface 3c. The attachment device 4 also acts as an attachment area for one of the four vertical spring legs (not shown) which are provided at each of the four corners of the driver's cabin. The two front spring legs can be fastened to each of the two attachment devices 4 by suitable attachment means 15. The centring sleeve 9 is shown provided with an extension 9b which acts as an area for attachment of one of the spring legs.

The arm's other end portion 3b is attached to the driver's cabin by means of suitable devices (not shown). In the joint area between the arm's end portion 3b and the torsion bar 2, the anti roll bar 1 is provided with torque-transferring devices. In fig. 1 the torque-transferring devices 5 are depicted as ball bodies located in grooves 6a and 6b which are provided in the torsion bar 2 and in the arm's end portion 3a respectively. It can be seen from the section along A-A that the grooves 6a, 6b, in which the ball bodies 5 are housed, are arranged at intervals in the torsion bar's 2 and the arm portion's circumferential direction.

In fig. 2 a section of the joint area between the torsion bar 2 and the arm's end portion is illustrated. An elastic bearing 11 is mounted in a bearing space 12 provided in the arm's end portion 3a. The elastic bearing 11 is provided with a bore 13 through which the attachment device 4 is passed. The attachment device 4 thereby holds the elastic bearing 11 in position in the bearing space 12. The elastic bearing is fixed to the vehicle's frame by attachment means 14.

The torsion bar 2 is mounted on to each of the arms 3 by the attachment device being secured in the torsion bar's bore 8. Due to the compression between the arm's

end portion 3 a and the torsion bar, the grooves 6a, 6b are partly plastically deformed during the assembly process. This is illustrated in detail in figures 4a and 4b which illustrate the grooves before and after assembly respectively. The torque- transferring devices 5 deform the grooves 6a, 6b so that tolerance variations are absorbed and the torque-transferring devices 5 fit into the grooves. The degree of deformation of the grooves will be dependent on both the hardness and design of the torque-transferring devices 5, as well as the characteristics and design of the material of the grooves. If it is subsequently desirable to dismantle the torsion bar 2 from the anti roll bar 1 , the attachment device 4 is released from engagement with the bore 8, the attachment device is withdrawn from the bore and the torsion bar 2 can be released.

The elastic bearing's elasticity makes it possible to release the torque-transferring devices 5 from one of the set of grooves 6a or 6b when the torsion bar 2 has to be dismantled from the anti roll bar 1. The torque-transferring devices 5 are then secured in the second of the set of grooves 6a or 6b, thereby preventing the torque- transferring devices 5 from falling out. It is, of course, also conceivable that some of the torque-transferring devices 5 are secured in one set of grooves 6a and the remaining torque-transferring devices 5 are secured in the other set of grooves 6b. The torque-transferring devices 5 may be secured in their grooves in various ways. One of the components — the torsion bar 2 or the arm's end portion 3a - may be made of a material that is softer than the second of the components - the torsion bar 2 or the arm's end portion 3a. The object is then achieved that when assembling the torsion bar 2 and the arm's end portion 3a, the torque-transferring devices 5 are pressed furthest into the softest component. Thus when the torsion bar 2 subsequently has to be dismantled, the torque-transferring devices 5 can be designed in such a way that they are held in place in the softest component when the torsion bar 2 is removed from the anti roll bar . Alternatively, the torque- transferring devices 5 may be secured in the grooves by an additional attachment means such as glue. Another possibility is that one of the components is provided with short cylindrical portions that ensure that the torque-transferring devices 5 are securely attached.

Fig 5 shows an alternative embodiment of the invention. The arms 3, here illustrated by one of them, are provided with a recess 20 at the end surface of each arm. As shown in fig 5, the grooves 6b are located at the bottom portion of the recess 20 with the two side walls of the recess surrounding the opposite sides of the torque- transferring devices 5. In this embodiment the torque-transferring devices 5 are shown as ball shaped elements.

An embossed section 21 is provided at the torsion bar 2. The grooves 6a are positioned essentially at the top surface of the embossed section 21. It is seen from

fig 5 that the grooves 6a have openings which extend from the top surface and somewhat down at the sides of the embossed section 21.

To secure the torque-transferring devices 5 in the grooves 6b of the recess, the areas of the side walls at the two sides of each of the torque-transferring devices 5, are exposed to local deformation as illustrated by arrows 22 in fig 6. By deforming these areas, the torque-transferring devices 5 are prevented from falling out of the grooves. The local deformation may be carried out by an hydraulic press integrated in the assembly station for torque-transferring devices 5. When fitting the torsion bar 2 and each of the arms 3 together for interconnecting, the shapes of the grooves 6a extending down the sides of the embossed section 21, at the as shown in fig 5, are adapted for fitting with the deformed areas of each of the torque-transferring devices 5. By this arrangement it is made sure that the embossed section 21 is to fitted closely into the recess 20 as shown in fig 7, and that the split line between the torsion bar 2 and each of the arms 3 is positioned at the centre line of the torque- transferring device 5 in the torque transferring direction. The correspondence between the spilt line of the torsion bar 2 and each of the arms 3, and the centre line of the torque-transferring device 5, ensures that the torque capacity is not reduced in the joint area of the torsion bar 2 and each of the arms 3.

As mentioned earlier the torque-transferring devices 5 may alternatively be secured in the grooves of the embossed section 21 and received in the grooves of the recess 20.

In fig 8, a spring unit 23 is shown connected directly to one of the arms 3. In accordance with the embodiment shown in this figure, the elastic bearing 11 is provided so that it is prevented from rotating. It is an object of this embodiment of the invention to prevent the elastic bearing 11 from rotating relative to stationary parts of the vehicle, such as the bracket 24 and the clamp 25. Arrangements to prevent the elastic bearing 11 from rotating may be achieved in various ways.

In one version the external elastic layer 17 of the elastic bearing 11 is provided so that is prevented from rotating. This may be provided by shaping the cross section of the external elastic layer non circular or by providing the external elastic layer with at least one locking element which is secured to a corresponding part of the vehicle. The locking element may be comprised by the external elastic layer 17 having a projection which is accommodated in receiving means arranged in/at a corresponding part of the vehicle. When the torsion bar 2 is dismantled from the anti roll bar 1, the arm 3 and the elastic bearing 11 ensure via the attachment device 4 that the driver's cabin is held in position and there is therefore no need to use a transverse crane during the dismantling operation (to relieve the weight of the driver's cabin from the attachment device).

When dismantling the elastic bearing 11, the attachment device 4 is released and withdrawn from the torsion bar's bore 8 and further withdrawn from the elastic bearing's bore 13 together with the centring sleeve 9. The elastic bearing 11 can now be freely be ejected through the bearing space's opening 15 while the anti roll bar is located in the vehicle. If the driver's cabin is fixed to the attachment device 4, the weight of the driver's cabin has to be relieved during the dismantling operation, but it is not necessary to use a transverse crane.

Figure 3 illustrates the construction of the elastic bearing 11. It can be seen in fig. 3 that the elastic bearing has a sleeve-like shape. The bearing wall is shown with an external curved surface preferably with a convex or concave shape which is provided by the design of the elastic bearing 16. The curved shape of the elastic bearing 16 allows forces to be absorbed both in the radial and axial directions. Furthermore, the elastic bearing 11 is covered with an external elastic layer 17 that absorbs tolerance variations between the elastic bearing 11 and the attachment means 14 connecting the elastic bearing 11 to the vehicle's frame. The elastic bearing 11 has an internal elastic layer 18 that abuts against the surface of the centring sleeve 9 and the bearing space's 12 internal wall 12'. When the driver's cabin is tilted, the internal elastic layer 18 has a certain amount of ability to absorb rotating motion before the rotating motion becomes so great that the internal elastic layer 18 acts as a sliding layer for motion between the arm and the elastic bearing 11 which is securely connected to the vehicle's frame.

Figure 3 further illustrates that the internal surface of the elastic bearing 11 is attached to the external surface of a first rigid inlay 19 and the external surface of the elastic bearing is attached to the internal surface of a second rigid inlay 20. The internal elastic layer 18 and the external elastic layer 17 cover the remaining surfaces of the first and the second rigid inlays 19, 20 respectively. The elastic bearing 11 and the elastic layers 17, 18 may be comprised of a connected material or of separate parts. The elasticity may be produced by an elastic material such as a rubber material. Furthermore, the elastic bearing and the elastic layers may be fixed to the rigid inlays in various ways, but a preferred attachment method will be vulcanisation.