WO2008002221A1

WO2008002221A1 - Vehicle cab arrangement

Info

Publication number: WO2008002221A1
Application number: PCT/SE2006/000819
Authority: WO
Inventors: Lena Larsson; Lorentz Andersson
Original assignee: Volvo Lastvagnar Ab
Priority date: 2006-06-30
Filing date: 2006-06-30
Publication date: 2008-01-03
Also published as: EP2038165A1

Abstract

The invention relates to a cab-over commercial vehicle with a forward tiltable cab, said cab comprising a driver's compartment and a hood. An engine is mounted to a frame located below an exterior floor of the driver's compartment and a radiator assembly for cooling at least said engine is mounted to the frame in front of the driver's compartment. The hood is arranged to enclose the radiator assembly and the cab has a tilt point located in front of the radiator assembly.

Description

VEHICLE CAB ARRANGEMENT

TECHNICAL FIELD

The invention relates to a vehicle of the cab-over type provided with an improved radiator arrangement.

BACKGROUND ART

Cab-over type vehicles, in particular trucks, are preferable over trucks with the engine located in front of the cab for several reasons. One reason is that by minimizing the space taken up by the cab and power plant it is possible to use a longer body or cargo space of a truck with the same over-all length. In the case of a tractor and trailer combination, it is possible to use longer trailer units within a predetermined or maximum allowed over-all length. The present invention is an improvement over known cab-over-engine trucks in general and is in particular aimed at solving problems relating to industrial trucks of the type used on construction sites.

For example, in many trucks where cabs are tilted forward over the engine, the engines are often inaccessible except when the entire cab is tilted forward, and even then there may be obstructions which can interfere with access for the mechanic. This problem has been solved by the cab disclosed in US 2 699 223, having the cab high on the chassis so that it is located substantially above the engine, by providing a compound hood with a front portion that swings up to give access to the front of the truck engine without moving the cab, and by providing front fenders which comprise the whole side closure below the cab base and are mounted at their rear end on a vertical axis so each fender can swing out of the way and give full access to the engine from each side. In addition, the fenders may be completely removed as soon as they are swung out from under the edge of the cab base. Also by having the cab over the engine the top of each fender forms the running board or step at the cab edge when the cab door is opened.

One problem with the above solution is that a cab provided with multiple openable portions becomes relatively complex. In addition, the disclosed cab can not be tilted open unless a front portion of the hood is opened prior to the tilting of the cab. A further problem with having the cab above the engine is that the total height of the vehicle is increased. This increases the air resistance which in turn increases fuel consumption. Also, a relatively high cab limits the available space above the cab for additional equipment, such as a hydraulic crane.

Today, an industrial truck should preferably not have a total height over 4 metres, making it desirable to keep the height of the cab as low as possible. Finally, the relatively high cab position is not only required by the engine position, but is also required in order to make room for the radiator without interfering with the line of sight of the driver. Even with the high cab position at least an upper part of the engine casing will still extend into an engine tunnel in an exterior floor of the driver's compartment, but the engine tunnel may, depending on type of vehicle, not extend through the interior floor. The solution may therefore allow the interior floor of the driver's compartment to be made completely flat. In combination with auxiliary equipment mounted to the firewall at the front of the vehicle, the available space for the feet of the driver may not always result in an ergonomic driving position.

In the subsequent text, the term "exterior floor" is defined as the lower part of the cab enclosing the driver's compartment. The term "interior floor" defines the floor of the driver's compartment. Typically, for an industrial truck, the exterior floor substantially coincides with the interior floor, on either side of an engine tunnel. For an over the highway truck, used for long distance haulage, the interior floor may be located separate from the exterior floor, level with or over the upper limiting surface of the engine tunnel. In modern cab-over haulage trucks the problem of providing a driver's compartment with a flat interior floor is often solved by increasing the height of the cab and raising the interior floor above the engine tunnel. Lowering the engine between the longitudinal beams of the vehicle frame to the desired level would be complicated and expensive. However, even if the interior floor is raised the exterior floor may comprise an engine tunnel and remain at substantially the same level as in an industrial truck as described above. Radiators in such vehicles are often mounted directly under the exterior floor of the cab due to limitations on maximum vehicle lengths. Factors such as the total height of the cab, engine and/or radiator position and the shape of the interior floor in the driver's compartment are therefore often conflicting.

The invention aims to provide an improved cab-over arrangement that overcomes the above problems relating to the tilting of the cab and the positioning of the radiator, while maintaining a relatively low total cab height. The invention further aims to provide a sufficient space for an ergonomically shaped interior floor within the driver's compartment.

DISCLOSURE OF INVENTION

The invention solves the above problems by means of a of a cab-over type vehicle with an improved radiator arrangement, as claimed in claim 1.

According to a preferred embodiment, the invention relates to a cab-over commercial vehicle with a forward tiltable cab, said cab comprising a driver's compartment and a hood. An engine is mounted to a frame, comprising two substantially parallel longitudinal beams, such as I- or U-beams or beams of a similar suitable cross-sectional shape, which frame is located below an exterior floor of the driver's compartment. The engine may be mounted between the beams and may also have a lower portion located at least partially below the lower sections of the said beams. A radiator assembly, comprising at least one radiator or other heat exchanging means, for cooling at least said engine is mounted to the frame in front of the driver's compartment. The hood may be arranged to enclose the radiator assembly and that the cab has a tilt point located in front of the radiator assembly. This allows the cab and hood to be tilted upwards and forwards to expose the radiator assembly and at least part of the engine.

The radiator assembly may be mounted in front of a vertical plane through a firewall at the front of the driver's compartment, preferably in front of the forward end of the frame. The radiator assembly may be mounted onto an extension of each beam or on separate attachment means mounted on and extending forward from said beams. An upper section of the top of the radiator assembly may be mounted above a substantially level section of an exterior floor of the driver's compartment, which compartment is located behind the radiator assembly. In this case level sections of an interior floor may be located adjacent or a short distance above the exterior floor on either side of an engine tunnel passing through the driver's compartment.

If the driver's compartment of the vehicle is provided with an interior floor raised above the engine tunnel, the top of the radiator assembly may be mounted above at least said exterior floor, as described above. Alternatively, the top of the radiator assembly may be located in a position up to or above a horizontal plane through the substantially level interior floor located over an engine tunnel in the driver's compartment.

A lower section at the bottom of at least a part of the radiator assembly may be mounted below a plane through a lower section the frame. The hood enclosing the radiator assembly, as well as the radiator assembly itself may be arranged to extend across up to half the width of the cab or more, depending on the cooling requirements for a particular engine and/or vehicle. The arrangement according to the invention allows the width and height of the radiator assembly to be varied freely, so that the assembly can be adapted to a wide variety of cabs having different widths, heights and floor positions, as well as the cooling requirements. A traditional mounting of a radiator is underneath the exterior floor of a forward section of the driver's compartment, as shown in Figure 1. By placing the radiator assembly in front of and partially overlapping a lower section of the driver's compartment, as shown in Figure 2, a number of advantages are achieved.

Due to future requirements for more powerful engines in combination with legal requirements for lower emissions, engines and auxiliary equipment will require increased cooling capacity. A conventional placement of the radiator as shown in Figure 1 is limited by requirements for ground clearance and ramp angle in the downward direction. The ramp angle is the angle measured between a line drawn from the lowest part of the chassis at the front of the vehicle down to the periphery of one of the front wheels and a horizontal line parallel to the longitudinal axis of the vehicle. The ramp angle should preferably be at least 25°. In the upward direction, the height of the radiator is limited by factors such as the location of the exterior floor of the driver's compartment and the shape of the engine tunnel. Finally, auxiliary equipment mounted at the front of the cab, as well as the space required for an ergonomically designed space for the driver's feet imposes sideways restrictions.

The invention involves mounting the radiator assembly in a position forwards and upwards in relation to the conventional placement into the position where it is located in front of and clear of at least the front firewall below the windscreen of the driver's compartment, as indicated in Figure 2. In this way the projected front area, that is the size of the radiator in a vertical plane when viewed from the front of the vehicle, may be increased from a standard size of about 0,6 m² (Volvo FH/FM series) to an area of 1 m², or greater if required.

According to one example the radiator assembly may be moved forwards and upwards to maintain a desired ramp angle. When it is clear of the front firewall of the driver's compartment the radiator assembly can be increased in size both upwards and sideways. In the upward direction, the maximum height is limited by the angle of view of the driver. The angle of view is measured as an angle downwards from a horizontal plane to the first part of the vehicle body blocking the line of sight for the driver. For a cab-over vehicle, this is usually the lower edge of the windscreen, but in this example it may also be the upper part of the hood enclosing the radiator assembly. Typical values for the angle of view are 25-30°. In the sideways direction, the maximum width is limited by the width of the cab and the hood enclosing the radiator assembly. Widening of the radiator assembly is preferably, but not necessarily, made symmetrically relative to a vertical centreline through the front of the cab.

According to a further example the radiator assembly may be moved forwards and upwards, in combination with the front axle of the vehicle being moved forwards relative to the frame, to increase the ramp angle. The radiator assembly can then be increased in size both upwards and sideways, as described above.

As stated above the radiator assembly may be mounted onto or between attachment means mounted on an extension of each beam of the frame or on or between separate attachment means mounted fixedly on and extending forward from said beams. The attachment means may comprise bars extending forward on either side of the radiator assembly. Depending on the size and position of the radiator assembly, a radiator may be mid-mounted onto each bar. The radiator assembly may comprise one or more heat exchanging units, including for instance a main radiator for the engine cooling water, an intercooler for intake air, an oil cooler, a condenser for an air conditioning unit, or similar units. A radiator assembly comprising more that one heat exchanging unit may be mounted one in front of the other, as well as side-by-side.

According to one example the radiator assembly may comprise a number of mid-mounted heat exchangers arranged with the larger unit or units mounted nearest the cab and the smallest unit or units mounted near the ends of the respective attachment means. For instance, a mid-mounted stacked assembly comprising an inner cooling water radiator, a central intercooler for intake air and an outer oil cooler could be used to create an assembly having a size that tapers away from the front of the cab. In combination with an enclosing hood having a similar shape, such an arrangement would assist in maintaining both a desired ramp angle and an angle of view.

In cases where it is important to maintain a maximum length of the vehicle it may be preferable to use the width of the cab to provide relatively wide heat exchangers or to arrange the heat exchangers side-by-side. For industrial trucks where the length of the vehicle is not critical, a stacked assembly may also be used. A stacked assembly may for instance include heat exchangers for intercoolers, oil coolers and/or air conditioners in front of or behind a main radiator for the engine.

The tilt point for the cab may be arranged at or adjacent the front ends of attachment means extending past the radiator assembly. The tilt point may be an actual or a virtual transverse axis about which the cab may be tilted. In the case of an actual axis, one or more pivot joints or similar are located so that they coincide with the tilt point. Alternatively, the tilting movement is created by a linkage or similar, wherein the linkage may be located behind the radiator assembly and cause a tilting movement about a virtual axis in front of the radiator assembly. Such a virtual axis need not necessarily be stationary during the tilting movement. According to one embodiment, the tilt point may be arranged on separate extension beams attached to the frame, either in front of each beam or at locations above the beams on both sides of the radiator assembly. The cab and the attached hood can be tilted upwards and/or forwards to expose the engine and the radiator assembly by means of a pair of pivot joints or a suitable linkage mechanism. The tilting movement of the cab is determined by the height and/or width of the radiator assembly itself, as well as the height and position of the radiator assembly relative to the exterior floor and front firewall adjacent the radiator assembly.

The attachment means for the hood and the radiator assembly may be used as crumple zones arranged to undergo deformation for absorbing impact forces during a collision event. In order to achieve this, the attachment means may be arranged as crash boxes being weakened in predetermined locations shaped to undergo a controlled deformation when subjected to forces over a predetermined magnitude. The hood and the radiator assembly may also be used to absorb collision forces in combination with the attachment means.

The cab may be provided with a suspension arrangement comprising front and rear damper means for absorbing movement of the cab relative to the frame. At least two damper means arranged at the rear of the cab. Each rear damper means may comprise a simple type of damper, such as a vulcanized rubber bushing or an air bellows. The rear dampers may be arranged to take up a vertical displacement of about ±50 mm relative to a normal cab position. At least two further damper means arranged at the front of the cab. Each front damper means may comprise a combined damper and pivot joint for the cab, wherein a pair of front dampers creates a tilt point for the cab and hood. Such a front damper means can be a torsional damper comprising one or more layers of rubber or a similar suitable elastomeric material vulcanized to an outer tubular section and a central core section. The torsional dampers may be arranged to take up a vertical displacement of up to ±50 mm at right angles to the central axis through the damper. Torsional dampers of this type may be arranged along a common central axis to act as combined pivot joint and torsion bar for the cab. The front dampers are preferably located in front of the radiator assembly, attaching the hood and the cab to the frame or a forward extension thereof. BRIEF DESCRIPTION OF DRAWINGS

In the following text, the invention will be described in detail with reference to the attached drawings. These schematic drawings are used for illustration only and do not in any way limit the scope of the invention. In the drawings:

Figure 1 shows a schematic side view of the front part of a cab-over truck with a radiator mounted according to according to a first embodiment of the invention;

Figure 2 shows a schematic side view of the front part of a cab-over truck with a radiator mounted according to according to a second embodiment of the invention;

Figure 3 shows a schematic side view of the front part of a cab-over truck with a radiator mounted according to according to a third embodiment of the invention;

Figure 4A shows a schematic illustration of a front view of a conventional truck;

Figure 4B shows a schematic illustration of a front view of a truck according to the invention; and

Figure 5 shows a side view of a truck as shown in Figure 4B with the cab tilted forwards.

EMBODIMENTS OF THE INVENTION

Figure 1 shows a schematic side view of the front part of a cab-over truck 10 provided with a radiator 11 mounted under the cab 12. The truck 10 comprises a frame 14 having two substantially parallel beams (one shown). An engine E is mounted between the beams of the frame 14 underneath at least the rear section of the cab 12 and extends through an engine tunnel 15 passing through the centre of the cab 12 between a pair of individual seats (not shown). The frame 14 is supported by a pair of front wheels 16 and at least one pair of rear wheels (not shown). In this example, a front wheel axle A extends under a central section of the engine.

An example of a conventional placement of the radiator as shown in Figure 1 is limited by requirements for ground clearance H and ramp angle α in the downward direction. The ramp angle α is the angle measured from the lowest part 18 of the chassis at the front of the vehicle down to the periphery of the front wheels 16. The ramp angle αi as shown in Figure 1 should preferably be at least 25°. In the upward direction, the height of the radiator is limited by a front section of an exterior floor 17 of the driver's compartment of the cab 12. As indicated in Figure 4A, auxiliary equipment mounted at the front of the cab imposes sideways restrictions.

In order to allow a larger radiator 19, according to a first embodiment of the invention (indicated in dashed lines), to be installed the position of the radiator 19 is moved forwards and upwards. The lower part of the radiator 19 and the lowest part 18 of the chassis at the front of the vehicle should be located so that the ramp angle αi remains the same or is increased. The upper part of the radiator 19 is located in front of a firewall (not shown) in a front substantially vertical section of the cab 12 below the level of the windscreen. The upper part of the radiator 19 is also located above a plane through a substantially level section of the exterior floor 17 of the cab 12. The maximum height of the radiator 19 and its enclosing hood (not shown) is limited by the angle of view β of the driver. The angle of view β is measured from a point P representing the eye of the driver as an angle downwards from a horizontal plane through said point P to the first part of the vehicle body blocking the line of sight for the driver. For a cab-over vehicle, this is usually the lower edge of the windscreen, but in this example it may be the upper part of the hood enclosing the radiator. In this example the angle of view βi is 30°. For a cab-over truck of the type shown in Figure 1 , the height of a single radiator unit located adjacent the front of the cab can be increased by at least 50% and still maintain the desired values for ramp angle oi and angle of view βi -

Figure 2 shows a schematic side view of the front part of a cab-over truck with a radiator mounted according to according to a second embodiment of the invention. In this embodiment the truck 20 comprises a frame 24 having two substantially parallel beams (one shown). An engine E is mounted between the beams of the frame 24 underneath at least the rear section of the cab 22 and extends through an engine tunnel 25 passing through the centre of the cab 22. The frame is supported by a pair of front wheels 26 and at least one pair of rear wheels (not shown). In this example, the front wheel axle has been displaced relative to the frame 24 towards the front of the truck and extends under a front section of the engine E.

According to this second embodiment of the invention a radiator 29 has been installed so that the upper part of the radiator 29 is located in front of a firewall (not shown) located in a front, substantially vertical section of the cab 22 below the level of the windscreen. The upper part of the radiator 29 is also located above a plane through a substantially level section of the exterior floor 27 of the cab 22. The lower part of the radiator 29 and the lowest part 28 of the chassis at the front of the vehicle are located in substantially the same position as the radiator 19 shown in Figure 1. As the front axle with the front wheels 26 have been moved forward relative to frame 24 and the radiator 29, the ramp angle cc₂ is increased. As the radiator 29 has not been moved relative to the front of the cab 22, the angle of view β2 remains the same.

Figure 3 shows a schematic side view of the front part of a cab-over truck 30 with a radiator assembly mounted according to according to a third embodiment of the invention. This embodiment is substantially identical to that of Figure 2, wherein the truck 30 comprises a frame 34 having two substantially parallel beams (one shown). An engine E is mounted between the beams of the frame 34 underneath at least the rear section of the cab 32, and extends through an engine tunnel 35 passing through the centre of the cab 32. The frame is supported by a pair of front wheels 36 and at least one pair of rear wheels (not shown). In this example, the front wheel axle has been displaced relative to the frame 34 towards the front of the truck and extends under a front section of the engine E.

According to this third embodiment of the invention a radiator assembly 39 comprising a main radiator 39a for engine coolant and at least one auxiliary radiator 39b has been installed so that the upper part of the radiator assembly 39 is located in front of a firewall (not shown) in a front, substantially vertical section of the cab 32 below the level of the windscreen. The upper part of the radiator 39, 39a is located above a plane through a substantially level section of the exterior floor 37a of the cab 32.

The least one auxiliary radiator 39b can be an oil cooler, a heat exchanger for charge air and/or a condenser for an air conditioning unit. The lower part of the radiator assembly 39 and the lowest part 38 of the chassis at the front of the vehicle are located in substantially the same position as the radiator 29 shown in Figure 2. In addition, the auxiliary radiator 39b is dimensioned so that its lower part does not project below the lowest part 38 of the chassis, and its upper part is below the upper part of the main radiator 39a. A hood 33 (indicated in dashed lines) is attached to the front of the cab 32 and arranged to enclose the radiator assembly 39 and shaped so that the ramp angle 0:₃ and the angle of view β₃ are not affected.

The cab 32 and the hood 33 are supported on the frame 34 by a pair of rear suspension dampers SR at the rear of the cab 32 and a pair of front suspension dampers SF adjacent the front of the hood 33. The front suspension dampers S_F comprise a pair of torsional dampers that also form the pivot joint for the forwards tiltable cab 32. The front suspension dampers SF are mounted onto a pair of front extension beams 34a (indicated in dashed-dotted lines) attached to each of the respective longitudinal beams 34. The front extension beams 34a comprise crash boxes which are part of a front deformation zone of the truck 30. During a front al collision, both the crash boxes 34a and the radiator assembly 39 can absorb collision forces in the longitudinal direction of the truck 30. The radiator assembly 39 can be mounted to the crash boxes 34a at or near their respective vertical mid-point.

In the case of a cab for long distance haulage, the cab including the drivers compartment has an increased height and an interior floor 37b is made substantially level to allow a driver to walk around in the cab. This requires the interior floor 37b to be located above the engine tunnel 35. An example of a level of such an interior floor 37b relative to the engine tunnel 35 is indicated with dash-dotted lines in the standard cab of Figure 3, merely to show that the upper part of the radiator 39, 39a can be located above a plane through both the exterior floor 37a and the alternative interior floor 37b of the cab 32. In fact, as the interior floor is raised the driver's seat will be located higher up. Consequently the point P representing the eye of the driver will be moved a corresponding distance, allowing a radiator assembly with a larger total height than the radiator assembly shown in Figure 3.

Figure 4A shows a schematic illustration of a front view of a conventional truck 40. The truck 40 is provided with a radiator 41 that is limited in size by it location under the front portion of the cab. Figure 4B shows a schematic illustration of a front view of a truck 42 according to the invention. According to one example a radiator 43 (indicated by dashed lines) that has been moved forwards and upwards relative to the cab has a maintained width but an increased height. According to a second example a radiator 44 (indicated by dashed-dotted lines) that has been moved forwards and upwards relative to the cab has an increased width and height.

Figure 5 shows a side view of a truck as shown in Figure 4B with the cab tilted forwards. The figure illustrates how the cab 32 is tilted about the front suspension dampers SF adjacent the front of the hood 33, while both the engine E and the radiator assembly 39 are exposed to allow access for service. The cab may also be tilted using a suitable linkage located in front of, on either side of or behind the radiator assembly.

The invention is not limited to the embodiments described above, but may be varied freely within the scope of the claims.

Claims

1. A cab-over commercial vehicle with a forward tiltable cab, said cab comprising a drivers compartment and a hood, wherein an engine is mounted to a frame located below an exterior floor of the driver's compartment and a radiator assembly for cooling at least said engine is mounted to the frame in front of the drivers compartment, characterized in that the hood is arranged to enclose the radiator assembly and that the cab has a tilt point located in front of the radiator assembly.

2. A cab-over commercial vehicle according to claim 1, characterized in that the radiator assembly is mounted in front of a vertical plane through a firewall at the front of the drivers compartment

3. A cab-over commercial vehicle according to claim 1, characterized in that the radiator assembly is mounted to the frame in front of the forward end of the frame

4. A cab-over commercial vehicle according to claim 3, characterized in that the top of the radiator assembly is mounted above a plane through a substantially level section of the exterior floor of the driver's compartment.

5. A cab-over commercial vehicle according to claim 4, characterized in that the top of the radiator assembly is mounted above a plane through a substantially level section of an interior floor of the driver's compartment.

6. A cab-over commercial vehicle according to claim 3, characterized in that the bottom of at least a part of the radiator assembly is mounted below a plane through a lower section the frame.

7. A cab-over commercial vehicle according to claim 1, characterized in that the hood enclosing the radiator assembly is arranged to extend across at least half the width of the cab.

8. A cab-over commercial vehicle according to claim 1, characterized in that the radiator assembly is mounted on or between attachment means extending forwards from the frame.

9. A cab-over commercial vehicle according to claim 8, characterized in that the tilt point of the cab is located adjacent the ends of said attachment means.

10. A cab-over commercial vehicle according to claim 8, characterized in that the cab is provided with a linkage located on either side of or behind the radiator assembly, which linkage has a virtual tilt point in front of the cab.

11. A cab-over commercial vehicle according to claim 8, characterized in that the attachment means form crash boxes arranged to absorb collision forces.