SE538556C2

SE538556C2 - A cross member for a vehicle frame, a vehicle frame and a vehicle comprising such a cross member

Info

Publication number: SE538556C2
Application number: SE1400596A
Authority: SE
Inventors: Johansson Anders; Pavlovic Boban; Söderberg Joakim; Hedberg Ann-Sofie; Salavati Nick; Ek Therese; Slettebo Christian; Burman Magnus
Original assignee: Scania Cv Ab
Priority date: 2014-12-15
Filing date: 2014-12-15
Publication date: 2016-09-20
Also published as: SE1400596A1; BR102015030577A2; DE102015015280A1

Description

A cross member for a vehicle frame, a vehicle frame and a vehicle comprising such a cross member.

TECHNICAL FIELD The present invention relates to a cross member for a vehicle frame according to the preamble of claim 1. The invention also relates to a vehicle frame comprising such a cross member according to claim 9 and a vehicle comprising such a cross member according to claim 10.

BACKGROUND Vehicle manufacturers are constantly trying to minimize the weight of their vehicles. This is especially important for heavy cargo vehicles such as trucks where a minimized vehicle weight may result in higher loading capacity. Minimized weight may also result in lowered fuel consumption and thus more economical vehicles with less environmental impact. A lot of various components are required in a vehicle and each component adds to the weight of the vehicle and also takes up valuable space. Vehicle manufacturers are therefore constantly trying to develop new space saving and weight saving solutions.

Vehicle frames typically comprise a pair of elongated frame rails arranged in parallel and extending along the longitudinal axis of the vehicle. Between the frame rails cross members are arranged to secure the frame rails to each other. Several different components are typically attached to the frame rails, such as axle suspensions, fuel tanks and compressed-air tanks. In order to save space and reduce weight it is known to integrate compressed-air tanks in cross members of the vehicle frame. For example document US2010/0327573 A1 discloses a structural air tank cross member comprising a tube section welded to back plates at its open ends. Two front plates with collars are arranged around the end of the tube section in order to protect the welds.

SUMMARY OF THE INVENTION Despite known solutions in the field, there is still a need to develop a cross member for a vehicle frame which reduces the vehicle weight and is space saving and at the same time achieves the requirements on structural strength.

An object of the present invention is to achieve a cross member for a vehicle frame which is lightweight.

Another object of the invention is to achieve a cross member for a vehicle frame which may also constitute a pressure vessel.

A further object of the invention is to achieve a cross member for a vehicle frame which has high structural strength and desired torsion stiffness.

The herein mentioned objects are achieved by a cross membercharacterizedby the features in the characterizing part of claim 1.

The herein mentioned objects are also achieved by a vehicle framecharacterized bythe features in the characterizing part of claim 9.

The herein mentioned objects are also achieved by a vehiclecharacterized bythe features in the characterizing part of claim 10.

According to an aspect of the present invention a cross member for a vehicle frame is provided. The cross member comprises a hollow tube portion and end pieces attached to the opposite ends of the tube portion, wherein the end pieces are adapted for attachment to frame rails of the vehicle frame. The tube portion is attached to the respective end piece by an adhesive joint.

By attaching the tube portion to the end pieces by an adhesive joint the number of additional fastening elements and attachment means is minimized and a cross member is achieved which is lightweight. Also, welding is avoided and thus the problems related to welds, such as a more complicated manufacturing process and less loading capability. The adhesive joint between the tube portion and the end pieces is an easy and economical way of attaching the end pieces to the tube portion and thus facilitates the manufacturing of the cross member.

The adhesive joint suitably comprises any form of adhesive applied between the tube portion and the end pieces. The adhesive is suitably an epoxy adhesive.

According to the invention at least one end piece comprises connection means for introduction of compressed air into the tube portion. By introducing compressed air into the cross member, the cross member may also constitute a pressure vessel. The connection means for introduction of compressed air preferably comprises an opening in the end piece and a valve arranged in the opening. By arranging the connection means for introduction of compressed air on at least one of the end pieces the envelope surface of the tube portion can be maintained intact without unnecessary openings. Thus, by arranging the connection means on the end piece instead of the envelope surface, the mechanical characteristics of the load carrying envelope surface is not deteriorated. This way, the mechanical characteristics of the cross member is optimized. Also, in the case where the tube portion comprises a composite material, arranging the connection means on the end piece facilitates the production process compared to arranging the connection means on the composite tube portion. Typically any number of connection means may be arranged on at least one end piece. The connection means is sealingly arranged on the at least one end piece such that the end piece is diffusion-proof.

According to the invention the tube portion has open ends and each end piece comprises a flange arrangement with a slot, wherein the end of the tube portion is inserted in the slot and adhered to the flange arrangement. Each end piece is preferably configured such that it comprises a back plate and a flange arrangement. The flange arrangement is arranged such that it extends perpendicularly from the plane of the back plate in the shape of the cross-section of the tube portion. Suitably, the flange arrangement extends perpendicularly from the plane of the back plate in the shape of an ellipse. The flange arrangement suitably comprises a first flange member and a second flange member coaxially arranged wherein the first flange member surrounds the second flange member such that a slot is formed between the first and the second flange member. The end of the tube portion is inserted in the slot whereby the first flange member surrounds the outside of the tube portion and the second flange member is arranged inside the tube portion. Adhesive is applied in the slot such that the tube portion is adhered to the flange arrangement. By configuring the end pieces such that the tube portion is attached by inserting the ends of the tube portion into a slot of a flange arrangement, the tube portion is adhered to the end piece both on the inside and the outside and a strong adhesive joint is thereby achieved. The flange arrangement also facilitates the mounting of the end pieces on the tube portion and thus facilitates the manufacturing of the cross member.

The first flange member and the second flange member may have a tapered cross-section such that the respective flange member becomes thinner the further away from the back plate it extends. By the tapered cross-section, the flange members are weaker at their respective ends such that they can follow the tube portion when it deforms due to mechanical loads. This way, the stress concentration in the adhesive is reduced whereby the risk for peeling is minimized. Preferably the adhesive is applied such that it covers and extends beyond the ends of the first and the second flange members. The adhesive may be applied through at least one opening in the back plate arranged in fluid communication with the slot of the flange arrangement.

The tube portion preferably comprises a lightweight material such as fibre composite, aluminium or magnesium. A cross member is subject to great mechanical stress and mechanical loads and the cross member preferably comprises materials with desired mechanical characteristics and thermal and chemical resistance. The tube portion may comprise a composite, for example a glass fibre composite or a carbon fibre composite. By designing the tube portion in a lightweight material the weight of the cross member and thus the weight of the vehicle is minimized. The cross member preferably has a weight lower than 35 kg, suitably between 20 and 35 kg.

The end pieces suitably comprise a metal such as aluminium or steel. Each end piece is preferably configured as one cast piece in order to increase the structural strength.

Since the cross member is arranged between the frame rails the height of the cross member is constrained by the height of the frame rails. Frame rails in a vehicle frame typically have a C-shape and the height of the cross member should thereby not exceed the inner height of the C-shaped frame rail.

According to an aspect of the invention the tube portion has an oval or elliptic cross-section. The tube portion suitably has an elliptic cross-section with the length of the minor axis (conjugate diameter) defining the height of the cross member and the length of the major axis (transverse diameter) defining the width of the cross member. The length of the minor axis of the elliptic tube portion is thus suitably shorter than the height of the frame rails. By configuring the tube portion with such an elliptic cross-section the volume of the cross member is optimized while it still fits within the height of the frame rails. The cross member suitably accommodates an inner volume between 20-35 litres.

Alternatively, the tube portion has a variable cross-section. The tube portion may thus have an oval or elliptic cross-section at the ends, such that the ends fit within the height of the frame rails, and a substantially circular cross-section at the mid portion of the tube portion.

According to an aspect of the invention at least one end piece comprises a drainage valve. When the cross member is filled with compressed air the compressed air will condense and liquid will accumulate inside the tube portion. It is important that this liquid is drained from the cross member for example in order to avoid the extra weight of the liquid and to optimize the volume capacity of compressed air inside the cross member. By arranging a drainage valve on an end piece, openings in the envelope surface of the tube portion are avoided and the mechanical characteristics of the cross member is thus optimized. The drainage valve is suitably a screw-down valve. Preferably, a hose is connected to the drainage valve inside the tube portion. At the other end of the hose a weight is arranged in order to ensure that the hose is maintained at the lowest point of the cross member where most of the liquid is accumulated. When the valve is open, the liquid will be pushed out through the hose due to the pressure caused by the compressed air inside the cross member. This way, a very efficient and simple way of draining liquid in the cross member is achieved. The hose is not fixedly attached to the cross member and is thus easy to remove and may thereby easily be replaced.

Suitably, one end piece comprises a connection means for introduction of compressed air and the other end piece comprises a drainage valve.

According to an aspect of the invention each end piece comprises a back plate arranged perpendicularly to the extension of the tube portion at the respective end of the tube portion. The back plates are arranged to cover the respective ends of the tube portions. The back plates preferably comprise at least one threaded hole in order to attach the back plate to the frame rails by means of a fastening means.

According to an aspect of the invention the tube portion has open ends and the ends of the tube portion are tapered towards the end pieces, wherein each tapered end surrounds and is adhered to a corresponding funnel shaped portion of the end piece. Each end piece comprises a funnel shaped portion protruding from the back plate and extending inside the tube portion. The funnel shaped portion thus converges inside the tube portion such that the diameter of the funnel portion increases the further away from the back plate it extends. The adhesive is suitably applied on the inside of the tapered ends of the tube portion and the outside of the corresponding funnel shaped portion. Preferably, a section of the tapered end is adhered to a section of the funnel shaped portion, wherein the section of the tapered end and the section of the funnel shaped portion has substantially the same inclination and are thus substantially parallel. By configuring the tube portion with tapered ends such that it surrounds the correspondingly funnel shaped portion of the end piece, a form fit between the tube portion and the end piece is achieved which further strengthens the attachment between the tube portion and the end piece.

Further objects, advantages and novel features of the present invention will become apparent to one skilled in the art from the following details, and also by putting the invention into practice. Whereas the invention is described below, it should be noted that it is not restricted to the specific details described. Specialists having access to the teachings herein will recognise further applications, modifications and incorporations within other fields, which are within the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS For fuller understanding of the present invention and further objects and advantages of it, the detailed description set out below should be read together with the accompanying drawings, in which the same reference notations denote similar items in the various diagrams, and in which: Figure 1 schematically illustrates a vehicle according to an embodiment of the invention; Figure 2a schematically illustrates a vehicle frame according to an embodiment of the invention; Figure 2b schematically illustrates a vehicle frame according to an embodiment of the invention; Figure 3a schematically illustrates a cross member according to an embodiment of the invention; Figure 3b schematically illustrates a detail of a cross member according to an embodiment of the invention; and Figure 4 schematically illustrates a cross member according to an embodiment of the invention.

DETAILED DESCRIPTION OF THE DRAWINGS Figure 1 schematically shows a side view of a vehicle 1 according to an embodiment of the invention. The vehicle 1 comprises a combustion engine 2, and a gearbox 4. The gearbox 4 is connected to the driving wheels 6 of the vehicle 1 and the driving wheels 6 are arranged on a vehicle frame 8. The vehicle frame 8 comprises two elongated frame rails 10 which are connected by cross beams (not shown) and a cross member (not shown) according to an embodiment of the invention. The vehicle 1 may be a heavy vehicle, e.g. a truck or a bus. The vehicle 1 may alternatively be a passenger car. Figure 2a schematically shows a top view of a vehicle frame 8 according to an embodiment of the invention. Driving wheels 6 are arranged on the vehicle frame 8. Only two driving wheels 6 are illustrated in Figure 2a, however, any number of driving wheels 6 or any type of wheels may be attached to the vehicle frame 8 within the scope of the invention. The vehicle frame 8 comprises two elongated parallel frame rails 10 which are connected by cross beams 11 and a cross member 12. Any number of cross members 12 could be attached to the frame rails 10 and thus replace the cross beams 11. The cross member 12 comprises a hollow tube portion 14 and end pieces 16, 16' attached to the opposite ends 18, 18' of the tube portion 14, wherein the end pieces 16, 16' are adapted for attachment to the frame rails 10 of the vehicle frame 8. The tube portion 14 is attached to the respective end piece 16, 16' by an adhesive joint. The adhesive joint suitably comprises any form of adhesive applied between the tube portion 14 and the end pieces 16, 16'. The adhesive may be an epoxy adhesive.

The tube portion 14 preferably comprises a lightweight material for example a fibre composite such as a carbon fibre composite material. By designing the tube portion 14 in a lightweight material the weight of the cross member 12 is minimized. The end pieces 16, 16' suitably comprise a metal such as aluminium or steel.

At least one of the end pieces 16, 16' comprises connection means (not shown) for introduction of compressed air into the tube portion 14. The connection means is thus arranged in connection to the inside of the tube portion 14. By introducing compressed air into the cross member 12, the cross member 12 also constitutes a pressure vessel. The compressed air may be intended for a brake system, suspension arrangement or similar. By arranging the connection means on the end piece 16, 16' instead of the envelope surface of the tube portion 14, the mechanical characteristics of the load carrying envelope surface is not deteriorated. This way, the mechanical characteristics of the cross member 12 is optimized. Typically any number of connection means may be arranged on at least one end piece 16, 16'. The connection means is sealingly arranged on the at least one end piece 16, 16' such that the end piece 16, 16' is diffusion-proof.

Figure 2b schematically shows a front view of a vehicle frame 8 according to an embodiment of the invention. The vehicle frame 8 is suitably confiaured as the vehicle frame 8 described in figure 2a. The cross member 12 thus comprises a tube portion 14 attached to end pieces 16, 16'. The end pieces 16, 16' are attached to the frame rails 10 by means of at least one fastening means such as a screw or bolt. The frame rails 10 are C-shaped and since the cross member 12 is arranged between the frame rails 10 the height of the cross member 12 is constrained by the height of the frame rails 10. The height of the cross member 12 does therefore not exceed the inner height of the reshaped frame rails 10.

Figure 3a schematically shows a cross member 12 for a vehicle frame 8 according to an embodiment of the invention. The cross member 12 is suitably configured as described in figure 2a. A part of the cross member 12 has been removed from the figure in order to show the inside of the cross member 12. The cross member 12 comprises a tube portion 14 with an oval or elliptic cross-section and the tube portion 14 has open ends 18, 18'. The tube portion 14 may have an oval or elliptic cross-section at the ends 18, 18' and a circular cross-section at the mid portion of the tube portion 14. The end pieces 16, 16' each comprise a flange arrangement 22 with a slot 24, wherein the ends 18, 18' of the tube portion 14 are inserted in the slot 24 and adhered to the flange arrangement 22. Each end piece 16, 16' comprises a back plate 20 and a flange arrangement 22. The flange arrangement 22 extends perpendicularly from the plane of the back plate 20 in the shape of the cross-section of the ends 18, 18' of the tube portion 14. In this embodiment the flange arrangement 22 thus extends perpendicularly from the plane of the back plate 20 in the shape of an oval or ellipse. The flange arrangement 22 comprises a first flange member 22' and a second flange member 22" coaxially arranged wherein the first flange member 22' surrounds the second flange member 22" such that the slot 24 is formed between the first and the second flange member 22', 22". The ends 18,18' of the tube portion 14 are inserted in the slot 24 whereby the first flange member 22' surrounds the outside of the tube portion 14 and the second flange member 22" is arranged inside the tube portion 14. Adhesive is applied in the slot 24 such that the tube portion 14 is adhered to the flange arrangement 22 both on the inside and the outside and a strong adhesive joint is thereby achieved.

The back plate 20 of the respective end piece 16, 16' comprises at least one threaded hole 26 for attachment to the frame rails 10 of the vehicle frame 8. At least one of the end pieces 16, 16' also comprises at feast one connection means 28 for introduction of compressed air. The connection means 28 suitably comprises an opening in the back plate 20 and a valve (not shown) arranged in the opening. Figure 3b schematically shows a cross-section view of the flange arrangement 22 of the end pieces 16, 16' of the cross member 12 as described in figure 3a according to an embodiment of the invention. The flange arrangement 22 comprises a first flange member 22' and a second flange member 22" arranged in parallel such that a slot 24 is formed between the first flange member 22' and the second flange member 22". An adhesive 30 is applied in the slot 24 such that adhesive 30 adheres on the inner side of the tube portion 14 of the cross member 12 and on the outer side of the tube portion 14. The first flange member 22' and the second flange member 22" are tapered in the direction away from the back plate 20 and towards the tube portion 14 of the cross member 12. This way, the flange members 22', 22" are weaker at their respective ends 23', 23" such that they can follow the tube portion 14 when it deforms due to mechanical loads. This way, the stress concentration in the adhesive 30 is reduced whereby the risk for peeling is minimized. The adhesive 30 may be applied through at least one opening 32 in the back plate 20 which is arranged in fluid communication with the slot 24. The adhesive is suitably applied on and beyond the ends 23', 23" of the first and the second flange members 22', 22" in order to increase the adhesive bond between the flange arrangement 22 and the tube portion 14. Figure 4 schematically shows a cross-section view of a cross member 12 for a vehicle frame 8 according to an embodiment of the invention. The cross member 12 could be configured as the cross member 12 described in any of figure 2a-6. The tube portion 14 of the cross member 12 is attached to an end piece 16, 16' by an adhesive and the end piece is attached to the frame rail 10 of the vehicle frame 8. A plurality of holes 26 in the end piece 16, 16' for attachment by means of a fastening mean (not shown) is illustrated by dashed lines. The end piece 16, 16' comprises a drainage valve 70 which extends through an opening in the frame rail 10. When the cross member 12 is filled with compressed air the compressed air will condense and liquid will accumulate inside the tube portion 14. It is important that this liquid is drained from the cross member 12. The drainage valve 70 is suitably a screw-down valve. A hose 72 is connected to the drainage valve 70 inside the tube portion 14. At the other end of the hose 72 a weight 74 is arranged in order to ensure that the hose 72 is maintained at the lowest point of the cross member 12 where most of the liquid is accumulated. When the drainage valve 70 is open, the liquid will be pushed out through the hose 72 due to the pressure caused by the compressed air inside the cross member 12. The hose 72 is removably attached to the drainage valve 70.

The foregoing description of the preferred embodiments of the present invention is provided for illustrative and descriptive purposes. It is not intended to be exhaustive or to restrict the invention to the embodiments described. Many modifications and variations will obviously be apparent to one skilled in the art. The embodiments have been chosen and described in order best to explain the principles of the invention and its practical applications and hence make it possible for specialists to understand the invention for various embodiments and with the various modifications appropriate to the intended use.

Claims

1. A cross member for a vehicle frame (8), comprising a hollow tube portion (14) and end pieces (16,16') attached to the opposite ends (18,18') of the tube portion (14), wherein the end pieces (16, 16') are adapted for attachment to frame rails (10) of the vehicle frame (8), wherein the tube portion (14) is attached to the respective end piece (16, 16') by an adhesive joint, characterized in that at least one end piece (16, 16') comprises connection means (28) for introduction of compressed air into the tube portion (14), said tube portion (14) having open ends (18, 18'), wherein each end piece (16, 16') comprises a flange arrangement (22) with a slot (24), said ends (18, 18') of the tube portion (14) are inserted in the slots (24) and adhered to the flange arrangements (22).

2. A cross member according to claim 1, characterized in that the tube portion (14) comprises a lightweight material such as fibre composite or aluminium or magnesium.

3. A cross member according to claim 1 or 2, characterized in that the end pieces (16, 16') comprise a metal.

4. A cross member according to any of the preceding claims, characterized in that the ends (18, 18') of the tube portion (14) has an oval or elliptic cross-section.

5. A cross member according to any of the preceding claims, characterized in that at least one end piece (16, 16') comprises a drainage valve (70).

6. A cross member according to claim 5, characterized in that a hose (72) is connected to the drainage valve (70) inside the tube portion (14).

7. A cross member according to any of the preceding claims, characterized in that each end piece (16, 16') comprises a back plate (20) arranged perpendicular to the extension of the tube portion (14) at the respective ends (18, 18') of the tube portion (14).

8. A cross member according to any of the preceding claims, characterized in that the ends (18, 18') of the tube portion (14) are tapered towards the end pieces (16, 16'), wherein the tapered ends (18, 18') surrounds and is adhered to a corresponding funnel shaped portion (40) of the end pieces (16, 16').

9. A vehicle frame (8), characterized in that it comprises a cross member (12) according to any of the claims 1-8.

10. A vehicle (1), characterized in that it comprises a cross member (12) according to any of the claims 1-8.