WO2010015649A1

WO2010015649A1 - Agricultural tractor

Info

Publication number: WO2010015649A1
Application number: PCT/EP2009/060141
Authority: WO
Inventors: Leo Goldoni
Original assignee: Goldoni S.P.A.
Priority date: 2008-08-08
Filing date: 2009-08-05
Publication date: 2010-02-11
Also published as: BRPI0917003A2; IT1391261B1; CN102112335A; JP2011530440A; ITMO20080217A1; KR20110051200A; EP2318227A1

Abstract

An agricultural tractor (1 ), comprising a chassis (2) that rests on wheels (3), two front wheels (3a) and two rear wheels (3b), and accommodates an engine (4) and an assembly (5) for transferring the power delivered by the engine to at least the rear wheels (3b), which is provided with a speed shifting device (6), the chassis (2) being contoured so as to form a driving station (7) for the assigned operator, which is equipped with a climbing/descent platform (7a), the speed shifting device (6) being provided with a primary shaft (6a) that is arranged substantially parallel and axially offset with respect to the driving shaft (4a), transmission means (8) being interposed between the driving shaft (4a) and the primary shaft (6a).

Description

AGRICULTURAL TRACTOR Technical Field

The present invention relates to an agricultural tractor provided with an assembly for transferring the power delivered by the engine to the wheels that has a reduced vertical space occupation. Background Art

Agricultural tractors are known which are widely used as means for towing trailers or for hitching specific farming equipment. These tractors are constituted substantially by a chassis that is supported on four wheels, two front ones and two rear ones, and is shaped so as to form a front compartment and a rear compartment for the containment of the elements for the rotary actuation of the wheels, a steering platform for the climbing and descent of the operator being interposed between such compartments.

The tractor is generally provided with an engine, which is accommodated in the front compartment of the chassis and is arranged so as to face the travel direction, i.e., so that the driving shaft is directed toward the rear part of the tractor, with reference to the forward travel direction, and in front of which there is a radiator. A friction clutch is fixed to the driving shaft by means of a flange and transmits the rotation directly to the primary shaft, which is coaxial to the driving shaft, of a speed shifting device, the output shaft of which is associated directly with a differential device for rotary actuation of the axle shafts of the rear wheels and, by means of a transmission coupling, to a differential device for the rotary actuation of the axle shafts of the front wheels. This transmission coupling is conveniently accommodated within a protective housing that ensures its functionality and safety.

These known agricultural tractors are not free from drawbacks, which include the fact that the space occupation of the friction clutch, of the speed shifting device and of the rear differential device creates a protrusion at the driving platform, which hinders free access and movement of the operator and also constitutes a danger for his safety while climbing on and off of the vehicle.

Further, the coupling for transmission to the front wheels and the corresponding protective housing protrude downward with respect to the chassis, reducing ground clearance, increasing the risk of impact with protruding parts of the terrain and, for some applications, making it impossible to install equipment such as underbelly lawn mowers. Disclosure of the Invention

The aim of the present invention is to eliminate the above-mentioned drawbacks of known tractors, by providing an agricultural tractor whose driving platform is clear, giving greater freedom of movement and comfort to the operator and ensuring greater safety in the step for climbing on and off the vehicle.

Within this aim, an object of the present invention is to increase the clearance from the ground below the chassis, so as to allow safe use of the tractor even on rough terrain and the use of equipment such as underbelly lawn mowers.

Another object of the invention is to provide an agricultural tractor that is simple, relatively easy to provide in practice, safe in use, effective in operation and of relatively low cost.

This aim and these and other objects which will become better apparent hereinafter are achieved by the present agricultural tractor, which comprises a chassis that rests on wheels, two front wheels and two rear wheels, and accommodates an engine and an assembly for transferring the power delivered by said engine to at least the rear wheels, which is provided with a speed shifting device, the chassis being contoured so as to form a driving station for the assigned operator which is equipped with a climbing/ descent platform, characterized in that said speed shifting device is provided with a primary shaft that is arranged substantially parallel and axially offset with respect to a driving shaft, transmission means being interposed between said driving shaft and the primary shaft. Brief description of the drawings

Further characteristics and advantages of the present invention will become better apparent from the following detailed description of a preferred but not exclusive embodiment of an agricultural tractor, illustrated by way of non-limiting example in the accompanying drawings, wherein:

Figure 1 is a schematic side view, partially in phantom lines, of an agricultural tractor according to the invention;

Figure 2 is a front view of the transmission means of the tractor according to the invention;

Figure 3 is a sectional view, taken along the line III-III of Figure 2; Figure 4 is a schematic plan view of the assembly for transferring power to the wheels in the tractor according to the invention. Ways of carrying out the Invention With reference to the figures, the reference numeral 1 generally designates an agricultural tractor.

The tractor 1 comprises a chassis 2, which rests on wheels 3, two front wheels 3a and two rear wheels 3b, and accommodates an engine 4 and an assembly 5 for transferring the power delivered by the engine to at least the rear wheels 3b, and is provided with a speed shifting device 6.

The chassis 2 is shaped so as to form a front compartment 2a and a rear compartment 2b, with reference to the forward travel direction indicated in the figures by the arrow A, between which there is a driving station 7 for the operator, which has a platform 7a for climbing on and off a seat 7b.

Advantageously, the speed shifting device 6 is provided with a primary input shaft 6a, which is substantially parallel and axially offset

(non-coaxial) with respect to a driving shaft 4a of the engine 4, transmission means 8 being interposed between the driving shaft 4a and the primary shaft 6a. Preferably, the primary shaft 6a is arranged at a height from the ground that is substantially lower than that of the platform 7a and the engine 4 is arranged so that its driving shaft 4a is directed toward the front part of the tractor 1. The driving shaft 4a is generally shaped so as to form a flywheel and is coupled to a friction clutch 9.

The transmission means 8 comprise at least one flexible element 10, which is closed in a loop and is wound around at least one driving wheel 11 , which is jointly connected for rotation to the driving shaft 4a, and at least one driven wheel 12, for the rotaiy actuation of the primary shaft 6a.

In a preferred embodiment, the flexible element 10 is constituted by a toothed belt, the wheels 1 1 and 12 being provided with teeth on their peripheral region, but such element might also be, for example, of the type of a flat belt, the wheels 1 1 and 12 being constituted by respective pulleys, by a chain or by another equivalent element.

Elements 10a for tensioning the flexible element 10, supported by the chassis 2, are provided.

The speed shifting device 6 is accommodated in the rear compartment 2b and the transfer assembly 5 provides an intermediate shaft 13 that has universal joints 14 at its opposite ends. In the figures, the reference numeral 14a designates a universal joint associated with a driven shaft 15 that is actuated rotationally by the driven wheel 12 and the reference numeral 14b designates a universal joint coupled to one end of the primary shaft 6a.

The driven shaft 15 is supported by the chassis 2 so that it can rotate freely about its own axis and is arranged so that it is coaxial with the primary shaft 6a; therefore, the intermediate shaft 13 is in a lower region proximate to the platform 7a, which is clear from protrusions that hinder the operator.

Further, the transfer assembly 5 has a rear differential device 16 for the rotary actuation of axle shafts 17 of the rear wheels 3b and is actuated rotationally by the output shaft 6b of the speed shifting device 6.

In the case of an all-wheel-drive vehicle, the transfer assembly 5 further has a front differential device 18 for the rotary actuation of axle shafts 19 of the front wheels 3a, which also is actuated rotationally by the output shaft 6b by means of a transmission shaft 20 which has universal joints 21 at its opposite ends. In the figures, the reference numeral 21a designates a universal joint associated with the differential device 18 and the reference numeral 21b designates a universal joint coupled to one end of the primary shaft 6a. It is noted that since the speed shifting device 6 is arranged in a rearward and lowered position with respect to the background art, the inclination of the transmission shaft 20 with respect to the ground is reduced, allowing to increase the clearance from the ground below the chassis 2. The chassis 2 is contoured in a lower region so as to contain the transmission shaft 20.

Finally, means 22 for cooling the engine 4 such as a radiator with a suction fan, are arranged behind the engine 4.

It is noted that the engine 4, the friction clutch 9, the speed shifting device 6 and the differential devices 16 and 18 are not described in detail, since they can be of any type and because their structure is not relevant for the purposes of the invention.

The operation of the present invention is as follows.

Upon starting the engine 4, by way of the transmission means 8 the rotation is transferred to the primary shaft 6a and from there, according to the transmission ratio set in the speed shifting device 6, to the output shaft 6b and therefore to the wheels 3.

In practice it has been found that the described invention achieves the proposed aim and objects, and in particular the fact is stressed that the climbing/descent platform of the tractor according to the invention is clear in an upper region from protrusions caused by the space occupation of the mechanical elements of the assembly for transferring power to the wheels.

Further, the particular arrangement of the speed shifting device allows to reduce the protrusion from the contour of the chassis of the shaft for transmission to the front wheels, increasing ground clearance.

The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims.

All the details may further be replaced with other technically equivalent elements.

In practice, the materials used, as well as the contingent shapes and dimensions, may be any according to requirements without thereby abandoning the scope of the protection of the appended claims.

The disclosures in Italian Patent Application No. MO2008A000217 from which this application claims priority are incorporated herein by reference.

Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims

1. An agricultural tractor (1), comprising a chassis (2) that rests on wheels (3), two front wheels (3a) and two rear wheels (3b), and accommodates an engine (4) and an assembly (5) for transferring the power delivered by said engine to at least the rear wheels (3b), which is provided with a speed shifting device (6), the chassis (2) being contoured so as to form a driving station (7) for the assigned operator, which is equipped with a climbing/descent platform (7a), characterized in that said speed shifting device (6) is provided with a primary shaft (6a) that is arranged substantially parallel and axially offset with respect to a driving shaft (4a), transmission means (8) being interposed between said driving shaft (4a) and the primary shaft (6a).

2. The tractor according to claim 1 , characterized in that said primary shaft (6a) is arranged at a height from the ground that is substantially lower than that of said platform (7a).

3. The tractor according to claim 1 or 2, characterized in that said engine (4) is arranged so that its driving shaft (4a) is directed toward the front part of said tractor, with reference to the forward travel direction (A).

4. The tractor according to one or more of the preceding claims, characterized in that said transmission means (8) comprise at least one flexible element (10), which is closed in a loop and is wound around at least one driving wheel (1 1), which is jointly connected for rotation to the driving shaft (4a), and around at least one driven wheel (12) for the rotary actuation of said primary shaft (6a).

5. The tractor according to claim 4, characterized in that said flexible element ( 10) is of the type of a flat belt, said driving and driven wheels (1 1 ,

12) being constituted by respective pulleys.

6. The tractor according to claim 4, characterized in that said flexible element (10) is of the type of a toothed belt, said driving and driven wheels (1 1 , 12) being provided with teeth on their peripheral region.

7. The tractor according to one or more of the preceding claims, characterized in that said speed shifting device (6) is accommodated within said chassis (2) to the rear of said platform (7a), with reference to the forward travel direction (A).

8. The tractor according to one or more of the preceding claims, characterized in that said transfer assembly (5) comprises an intermediate shaft (13) that lies below said platform (7a) and is provided at its opposite ends with respective universal joints (14), of which one (14a) is associated with a driven shaft (15) actuated rotationally by said driven wheel (12) and the other one (14b) is associated with said primary shaft (6a).

9. The tractor according to one or more of the preceding claims, characterized in that said transfer assembly (5) comprises a transmission shaft (20) provided at its opposite ends with universal joints (21), of which one (21b) is associated with the output shaft (6b) of said speed shifting device (6) and the other one (21a) is associated with a front differential device (18) for the rotary actuation of the axle shafts (19) of the front wheels (3a).

10. The tractor according to one or more of the preceding claims, characterized in that said transfer assembly (5) comprises a rear differential device (16) for the rotary actuation of the axle shafts (17) of the rear wheels (3b) and is actuated rotationally by the output shaft (6b) of said speed shifting device (6).

11. The tractor according to one or more of the preceding claims, characterized in that it comprises a friction clutch (9) coupled to said driving shaft (4a).

12. The tractor according to one or more of the preceding claims, characterized in that it comprises means (22) for cooling said engine (4), which are accommodated inside said chassis (2) at the rear region of said engine, with reference to the forward travel direction (A).