Fender mounting assembly for utility vehicles

A utility vehicle such as an agricultural tractor comprises a steerable wheel secured to a wheel carrier which is mounted to a vehicle frame. The wheel is steerable through a range of steering angles about a substantially vertical steering axis A fender is mounted above the wheel on a support arm. The support arm is fixed relative to the wheel carrier so as to pivot with the wheel during steering through the whole of said range. The fender is pivotally mounted to the support arm at a pivoting mount located above the wheel. The fender is forced to pivot with respect to the wheel and support arm when the fender engages the vehicle frame.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims the benefit of and priority from United Kingdom Application No. 1121888.0, filed Dec. 20, 2011, the entire disclosure of which is hereby incorporated by reference.

FIELD OF INVENTION

The invention relates to utility vehicles such as agricultural tractors and particularly to fenders mounted on steerable wheels.

BACKGROUND

The use of fenders is well known for many types of vehicle. Fenders are employed to prevent water, mud and debris from being propelled an excessive distance from rotating tyres. Agricultural tractors and other similar utility vehicles have included fenders on front steerable wheels for many years, especially on medium and high horsepower tractors. In such arrangements, each fender typically has an independent support arm which secures the fender to the associated wheel carrier. The support arm is shaped to position the fender above the wheel. Often adjustment means are provided to cater for differently sized wheels and tyres and serve to maintain an acceptable separation between the fender and tyre.

The support arm in known arrangements is fixed to the wheel carrier so that the fender maintains a constant positional relationship with the tyre as the wheel is pivoted during steering. However one drawback faced with the inclusion of fenders is the reduction in available steering angle caused by striking of the fender on the vehicle frame at extreme steering angles. This is compounded by the common design of fenders being wider than the tyre. A simple solution to this problem has been to construct the fenders to be easily removable to allow them to be removed when greater manoeuvrability is required. This solution however is far from satisfactory and, although the cheaper option, is time consuming for the operator.

Another solution has been to mount the support arm to the wheel carrier with a sprung pivoting assembly. The pivoting assembly allows the support arm and fender to pivot with respect to the wheel carrier and tyre thus allowing the wheel to pivot to the maximum steering angle permitted by the geometry of the vehicle frame. The pivoting assembly is provided with a spring which biases the fender and support arm into the neutral position where in the fender is aligned with the tyre.

For shallow steering angles the support arm simply follows the wheel carrier and maintains a fixed relationship between the fender and tyre. At larger steering angles however the fender engages the side of the vehicle frame typically via a stop member and is forced to pivot with respect to the wheel and carrier.

To accommodate the pivoting movement of the support arm, the distance between the arm and the wheel must be sufficient. This places limitations on the placement of suspension components such as hydraulic cylinders connected between the front axle and vehicle frame. Moreover the freedom of the axle to pivot around a longitudinal axis is restricted especially when the track width is narrow.

In known arrangements the axis of pivot is substantially vertical between the support arm and wheel carrier for ease of construction. However, this arrangement also has significant limitations enforced by the limited angle through which the support arm can pivot without striking the tyre. Also, at full steering lock the separation between the support arm and tyre is minimal leading to an increased risk of large debris on the tyre striking the support arm and causing damage.

SUMMARY OF INVENTION

It is an object of the invention to provide an improved fender mounting assembly which alleviates the aforementioned problems.

It is another object of the invention to provide a fender mounting assembly suitable for use on agricultural tractors which is more robust and has improved handling of large debris carried by the tyres.

It is yet another object of the invention to provide a fender mounting assembly on a utility vehicle which improves the design freedom in relation to positioning axle suspension means.

In accordance with the invention there is provided a utility vehicle comprising a steerable wheel secured to a wheel carrier which is mounted to a vehicle frame, the wheel being steerable through a range of steering angles about a substantially vertical steering axis, and a fender mounted above the wheel on a support arm, the support arm being fixed relative to the wheel carrier so as to pivot with the wheel during steering through the whole of said range, the fender being pivotally mounted to the support arm at a pivoting mount located above the wheel, wherein the fender is forced to pivot with respect to the wheel and support arm when the fender engages the vehicle frame.

By allowing the fender to pivot with respect to the support arm and keeping the support arm fixed with respect to the wheel carrier, the spatial relationship between the support arm and the wheel is maintained at all times thus keeping a sufficient separation and avoiding damage by large debris carried on the tyre. Moreover, the support arm can be positioned much closer to the wheel compared to known arrangements having a pivoting arm thus making it easier to accommodate other components such as axle suspension components.

Preferably the arrangement further comprises biasing means which biases the fender into a normal position wherein the fender is substantially aligned with wheel. By way of example the biasing means may include a spring which acts between the fender and the support arm.

The fender may comprise a skeleton frame and a body, the skeleton being pivotally mounted to the support arm, and the body being mounted to the skeleton, by screws or bolts for example. Preferably the skeleton is formed of a ridged robust material such as steel whereas the body is preferably formed of a plastic by a moulding technique thus minimising costs.

In a preferred arrangement the fender pivots with respect to the support arm around a pivot axis which is inclined to the vertical so that, upon engagement with the frame, the fender pivots away from the wheel. Advantageously, by inclining the pivoting axis of the fender the separation between all parts of the fender and the associated wheel are maintained at a sufficient distance thus avoiding damage by large debris carried on the tyre. This is in contrast to known assemblies wherein at least one edge of the fender converges on the swept envelope of the tyre.

The fender preferably engages the vehicle frame via a stop member which is formed of a resilient material such as rubber. This stop member may be mounted on an extension member, or rod, secured to the fender to cater for different frame geometries.

It should be understood that the term ‘vehicle frame’ is intended to include any part of the vehicle body which engages or comes in to contact with the fender or stop member. This may include the chassis, sheet metal of the hood, or other functional or aesthetic component secured thereto.

As mentioned above, the invention improves the freedom of design of the front axle architecture. Therefore the wheel carrier may be mounted to the vehicle on the end of an axle, and a suspension cylinder may be connected between the axle and the frame. Alternatively the wheel carrier may be mounted to the frame via an independent wheels suspension assembly which includes a four-bar linkage for example.

The frame may have a concave part which receives an edge of the wheel when at a limit of the steering range, and wherein the fender engages the frame beyond the concave part. Advantageously, the provision of a concave part in the frame increases the available space for the wheel to pivot to tighter steering angles.

Preferably the support arm is shaped to position the fender pivoting mount forwardly of the centre of the wheel hub.

The support arm may be adjustable in a direction parallel to the axis of rotation of the wheel to cater for different sized wheels.

The invention lends itself particularly well to agricultural tractors having steerable front wheels mounted either side of a hood and disposed forwardly of a cab. However it should be appreciated that the invention is also applicable to other utility vehicles which employ fenders on steerable wheels and suffer from angular limitations enforced by a vehicle frame.

DESCRIPTION OF EXAMPLE EMBODIMENT

With reference toFIGS. 1,2and3, an agricultural tractor10includes a pair of front wheels12, a pair of rear wheels14, a driver's cab16and a frame18. The driver's cab16is mounted or suspended upon the frame18. Shown in highly simplified form inFIGS. 1,2and3, frame18may include the housing for a transmission and a clutch as per conventional agricultural tractors. The frame18may continue forwardly of the cab16and provide a support structure for an engine (not shown). In some vehicles, the engine block itself forms part of the frame and may be integrated with the transmission housing.

A front linkage assembly20is also shown inFIGS. 1,2and3mounted to the front of frame18. The front wheels12are mounted in a known manner to respective ends of a front axle22which is suspended in a known manner from frame18. Each front wheel12has associated therewith a fender24,25which are each supported by a respective support arm (not shown inFIGS. 1 to 3) to maintain a positional relationship with respect to the associated front wheel12.

The general principle of a pivoting fender24is illustrated inFIG. 3in which a stop26engages with the side of frame18at extreme steering angles (to the left in this case). It can be seen fromFIG. 3that the right-hand fender25is maintained in a normal position. It will be appreciated that right-hand fender25pivots with respect to the associated front wheel12for high steering angles to the right.

A more detailed description of the construction of the fender assembly will now be described with reference toFIGS. 4 to 11. The following description will be made with reference to the left-hand front fender24and the figures omit the right-hand assembly for clarity. However it should be understood that the construction of the right-hand fender assembly will mirror that of the left.

With particular reference toFIGS. 10 and 11, a wheel carrier designated generally at30has a lower principle part30a, an upper principle part30b, and a wheel hub32. The wheel carrier30pivots about a steering axis defined by king pin34. The wheel hub32may be driven by means of a reduction gear that is accommodated in it's interior, for which purpose the input shaft (not shown) of said wheel hub32is connected to the vehicle transmission via a driveshaft housed in axle22. The wheel carrier30is also provided with an arm36to which a steering rod38is connected by a vertical pin39. A hydrostatic steering device (not shown) controls movement of the steering rod38so as to swivel the wheel carrier30about the steering axis into the desired direction of travel. For instance,FIG. 4shows the wheel carriers30steered to the right whilstFIGS. 5 to 9show the wheel carrier30steered fully to the left.

A support arm40is welded at it's lower end to mounting plate42which is bolted to the upper part30bof wheel carrier30. As shown inFIGS. 10 and 11, the plate42is provided with elongated slots42awhich allow adjustment of the fender24in direction parallel to the rotation axis of wheel12.

The support arm40includes an upright part40a, an angled part40bextending forwardly, outwardly and upwardly from the upright part40a, and a transverse part40cwhich includes part of a pivoting bracket44for fender24. With particular reference toFIGS. 8 and 9, fender24includes a plastic moulded body part24aand a rigid metal skeleton frame24b. The skeleton frame24bis pivotally mounted at its forward end to support arm40by pivoting bracket44. The pivoting bracket44allows the fender24to pivot between a normal position (FIG. 4) and a displaced position (FIG. 5). Biasing means (not shown) act between the fender24and support arm40to bias the fender24into the normal position shown inFIG. 4.

The axis around which fender24pivots on support arm40is inclined to the vertical so that the rear edge of fender24moves upwardly and outwardly away from wheel12. At maximum steering angle this increase separation between the fender24and wheel12and has little effect on the function of fender24because debris thrown up by the wheel is not directed at the windows cab16but is instead shielded by frame18.

Fender24includes a stop26mounted on an end of a stop arm46. At large steering angles to the left, stop26engages with the side of frame18which prevents the fender24from contacting the frame18. The continued steering force provided by steering rod38forces the fender24to pivot with respect to the support arm40as shown inFIG. 5for example. This prevents the fender24from limiting the steering angle achievable.

The frame18includes a pair of rear concave parts18adisposed behind the axle22and a pair of front concave parts18bdisposed in front of the axle22. These concave parts allow for an increased steering angle and receive the rear and front edges respectively of the wheel12at maximum steering angles.

Although described in relation to an agricultural tractor10it is envisaged that the fender mounting arrangement described may be employed on other utility vehicles with steerable front wheels without deviating from the scope of the invention.

Furthermore, although the pivot axis of the Fender has been described as inclined to the vertical, a vertical pivot axis may be employed although it is envisaged that this will result in an inferior arrangement to that described above.