GB2037239A

GB2037239A - A separable junction for an air intake system of a commercial vehicle

Info

Publication number: GB2037239A
Application number: GB7940970A
Authority: GB
Original assignee: Daimler Benz AG
Current assignee: Daimler Benz AG
Priority date: 1978-12-02
Filing date: 1979-11-27
Publication date: 1980-07-09
Also published as: GB2037239B; FR2442737A1; DE2852225C2; CH641875A5; IT7950918A0; AT380214B; ATA741179A; IT1120637B; DE2852225A1; FR2442737B1; SE7909917L; SE436912B

Abstract

<IMAGE> The engine air intake duct 4 is secured to the rear wall of the tilt cab 1 and is connected to an air filter 9 through a separable joint 13 which consists of a resilient bellows 22 connected at its lower end 23 to the air filter 9 and at its upper end 25 to a bracket 27, 28 mounted on the driver's cab 1. The bracket 27, 28 has an upper collar 29 to which a resilient sealing bead 31 is secured in a sealed manner and the lower end of the inlet duct 4 is funnel- shaped 32 and adapted to engage the bead 31 in a sealed manner. <IMAGE>

Description

SPECIFICATION Separable junction in the air intake system of a commercial vehicle The invention relates to a separable junction eiement in an air intake system for the supply of air to an internal combustion engine of a commercial vehicle, in which the driver's cab is resiliently mounted relative to the vehicle chassis and is also adapted to tip forwards transversely to the direction of travel and along the rear wall of which an inlet duct of the air intake system extends in the narrow space in front of the load-carrying superstructure.

In the case of the driver's cab of a commercial vehicle which is sprung relative to the vehicle chassis and which is mounted to tip about a horizontal axis extending transversely of the direction of travel, it is desirable that the air for the engine should be taken in over the roof of the driver's cab.

The indrawn air is designed to pass through the aforementioned duct which extends behind and which is mounted on the rear wall of the driver's cab, to the air filtered which is mounted on theivehicle chassis. Between the part which is mounted on the driver's cab and that which is mounted on the vehicle chassis, considerable relative movements occur as a result of the permitted spring travel of the sprung mounted driver's cab. Therefore, a resilient junction or transition element capable of accommodating relative movement must be provided in the intake duct.

In addition, a point of separation is required in the intake duct so that the driver's cab can be tilted. The junction element is therefore intended at the same time to be constructed as a separation element.

The problem resides therefore in the fact that when the driver's cab is in the normal operative position the parts of the air intake system which are associated on the one hand with the chassis and on the other with the driver's cab must be guided reliably together and a necessary sealing-tightness therebetween guaranteed against a penetration of dust and rain water of water spray. Particularly in the case of known vehicles with high load carrying superstructures which extend quite close to the driver's cab the lack of space necessitates a spacesaving oval or even flat cross-section for the intake duct and a location of the junction element in an oblique position.By virtue of the actual weight of the hose element which as a rule is produced from rubber or synthetic plastics material and which is constructed as a resilient bellows, the hose element, particularly if the ambient temperature is very warm so that the hose material has become softened, may well move out of its original working position when the driver's cab is tilted and when the junction has been broken, so that when the driver's cab is tilted back, the top and bottom parts of the junction element no longer coincide.

In the case of the hitherto known constructions employed in commercial vehicles, the "threading in" of the parts which are to be joined can often only be achieved with manual assistance as the driver's cab is tilted back. This is particularly difficult andre- quires skill and additional labour if the junction element is located on one side of the driver's cab while the actuating device for tipping the driver's cab is located on the other side thereof. Furthermore, in the case of known constructions, leaks occur at the junction due to imperfect centring and due to the fact that the parts which are pressed on one another solely by the inherent resilience of the junction element become detached from one another on poor roads which cause movement at the junction.Since in certain circumstances, the driver's cab becomes quite some distance remote from the chassis as a result of the considerable spring travels entailed in providing acceptable driver comfort, and since the chassis has different natural frequencies from the driver's cab, a fairly large gap can arise between the top and bottom parts of the junction and separation element. As a result, it is even possible during a journey on poor roads for the two parts of the junction element to become separated from each other in an undesirable fashion.

The object of the invention is to avoid these disadvantages and to propose a junction and separation element which even under extreme circumstances ensures a holding together and sealing of the two separable parts of the junction element and which furthermore ensures that after tipping of the driver's cab, satisfactory centring and sealing of the junction point takes place automatically without outside help when the driver's cab is swung back into the normal position.

According to the invention there is provided a separable junction for an inlet duct for the supply of airto an internal combustion engine of a commercial vehicle, of which the sprung driver's cab is adapted to tilt forwards transversely to the direction of travel and to the rear wall of which the inlet duct extends upwardly in the space in front of the load-carrying superstructure, the junction including a bellows formed of a resilient material, the bellows being fixed at one end to an air filter mounted on the vehicle chassis and, at its other end, being supported by a bracket mounted on the driver's cab which is resiliently supported with respect to the chassis.In this respect, the bracket may comprise a collar around which the top end of the bellows is fastened and which is connected to a strut which at its-free end is connected to the sprung console for the rear suspension of the driver's cab. As a result of this, the two separable parts of the junction element, while taking into account the sprung console of the rear driver's cab suspension, are accurately associated with each other when the driver's cab is tilted back since for accommodating and fixing the springing parts of the console with a transverse- leaf spring and a vibration damper, an accurate guidance between the driver's cab and the console associated with its rear suspension is provided, together with a substantially rigid interlocking of these parts.

In a further development of the invention, it is possible to provide on the upper free collar edge of the bracket a sealing bead and further more the bottom end of the inlet duct may be widened out to a funnel-shape so that it is expediently adapted to fit and can engage over the sealing bead. Since after the driver's cab has become interlocked with its sprung console, only negligible relative movements can occur between the lower and the upper parts of the junction, the necessary security of seal is also achieved. The considerable spring travels of the sprung driver's cab mounting are reliably accommodated only by the bellows unit which is sealed tight at both ends.

The invention will now be described in greater detail by way of example with reference to the accompanying drawings, in which: Figure 1 is a side view of the front part of a commercial vehicle with an air intake system equipped according to the invention and in the operative position; Figure 2 shows the same part of commercial vehicle with the driver's cab tipped forwards about a transverse axis; Figure 3 shows on an enlarged scale a crosssection taken on the line Ill-Ill in Figure 1, and Figure 4 shows a cross-section taken on the line IV-IV in Figure 2.

In the front part of a commercial vehicle which is shown in Figures 1 and 2, there is between the driver's cab 1 and the payload carrying body 2 only a small space 3 in which it is possible to accommodate an air intake shaft 4 throhugh which air for the engine 5 is drawn in over the roof 6 of the driver's cab 1. The payload carrying body 2 is mounted on longitudinal members 8 through intermediate mem bers 7. On one of the longitudinal members 8 there is also mounted an air filter 9 which is connected via a line 11 to the engine 5. The air filter 9 is in part located beneath the payload carrying body 2, be cause parts of the tiltable driver's cab 1,for example the mudguard 12, must be able to pivot freely past it.

Therefore, it is necessary that a junction and separa tion element 13 be disposed obliquely to the vertical and to the horizontal, so that a connection can be made to the air intake shaft 4 which, in cross section is a relatively flat oval.

The rear part of the driver's cab 1 which is spring mounted at the front, on the axle 14, and which is also pivotable about this axle, is supported through feet 15 on springingly-resilient rubber pads 16 mounted on a console 17. This console is resiliently supported on the longitudinal members 8 by a leaf spring 18 and oscillation dampers 19. A separable interlocking device 21 holds the driver's cab and the console 17 together in the working position, as shown in Figure 3. Before the driver's cab can be tilted forwards this interlocking device is opened so that the driver's cab 1 with its supporting feet 15 can be moved away from the console 17. This separation must also be performed by the individual parts of the junction and separation element 13.So that this may occur as desired and in the manner according to the invention and so that the console 17 can also move in respect of the longitudinal members 8, according to the loading on its springs, the junction element 13 includes a bellows 22, the bottom end 23 of which is fixed in a sealed manner to a filter connection 24 of the vehicle engine air filter. The top end 25 of the bellows 22 is sealed to a collar 26 of a bracket 27. The bracket 27 also has a strut 28 which at its free end is connected to the sprung console 17 for the rear suspension of the driver's cab 1. A sealing bead 31 is secured to the top free collar edge 29 of the bracket 27.The bottom end of the air intake shaft 4 has a funnel-shaped widened out part 32 which is adapted to fit over the sealing bead 31 so that it can engage over the latter and, as shown in Figure 3, bear in sealing-tight fashion on the free sealing edge of the sealing bead 31.

In this way, in the operating condition a seal is provided between the bead 31 and the funnelshaped widened out part 32 which can be maintained even with considerable vibration deflections of the console 17 of the driver's cab 1, since only negligble displacements, through the resilience of the rubber cushion 16, are possible between the bracket 27 and the cab 1 and these do not adversely affect the seal at the sealing point 31/32. As Figure 4 shows, the embodiment according to the invention ensures that after a tilting forward of the driver's cab 1 and when it is set back again onto the console 17, the funnel-shaped widened out part 32 is brought to coincide with the sealing bead 31 in sealing-tight fashion without outside assistance.

Claims

1. A separable junction for an inlet duct for the supply of air to an internal combustion engine of a commercial vehicle, of which the sprung driver's cab is adapted to tilt forwards transversely to the direction of travel and to the rear wall of which the inlet duct extends upwardly in the space in front of the load-carrying superstructure, the junction including a bellows formed of a resilient material, the bellows being fixed at one end to an air filter mounted on the vehicle chassis and, at its other end, being supported by a bracket mounted on the driver's cab which is resiliently supported with respect to the chassis.

2. A junction according to claim 1, wherein the bracket consists of a collar about which the top end of the bellows is fastened and which is connected to a strut, the free end of which strut is connected to a sprung console for the rear suspension of the driver's cab.

3. Ajunction according to claim 1 or 2, wherein a sealing bead is secured onto a top free collar rim of the bracket.

4. A junction according to claim 1, 2 or 3, wherein the bottom end of the inlet duct is widened out to a funnel-shaped adapted to fit and engage over the sealing bead.

5. A separable junction for an inlet duct for supplying air to an internal combustion engine of a commercial vehicle having a sprung tilt cab substantially as described herein with reference to and as illustrated in the accompanying drawings.