Work vehicle

A work vehicle includes a vehicle body, a travel device, a driving source, and a cooling device. The travel device is provided below the vehicle body. The driving source is disposed in a front part of the vehicle body. The driving source generates driving power for the travel device. The cooling device is disposed on one side in the vehicle width direction of the vehicle body and rearward of the driving source.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a U.S. National stage application of International Application No. PCT/JP2015/055084, filed on Feb. 23, 2015. This U.S. National stage application claims priority under 35 U.S.C. § 119(a) to Japanese Patent Application No. 2014-252484, filed in Japan on Dec. 12, 2014, and Japanese Patent Application No. 2014-252485, filed in Japan on Dec. 12, 2014 the entire contents of which are hereby incorporated herein by reference.

BACKGROUND

Field of the Invention

The present invention relates to a work vehicle.

Description of the Related Art

For example, a bulldozer in Japanese Laid-open Patent 2013-204295 has a cooling device disposed at the front end of the vehicle body.

However, when the cooling device is disposed at this position, there is a possibility that earth and sand may enter the cooling device through the front during work and reduce the performance of the cooling device.

SUMMARY

An object of the present invention is to provide a technique that can prevent a reduction in performance of a cooling device.

A work vehicle according to a first exemplary embodiment of the present invention is provided with a vehicle body, a travel device, a driving source, and a cooling device. The travel device is provided below the vehicle body. The driving source is disposed in a front part of the vehicle body. The driving source generates driving power for the travel device. The cooling device is disposed rearward of the driving source and on one side in the vehicle width direction of the vehicle body.

The vehicle body may also have a work area positioned facing the cooling device rearward of the driving source.

The work vehicle may be further provided with a device to be maintained that requires maintenance and is disposed between the driving source and the work area.

The work vehicle may be further provided with a fuel tank that is disposed in a rear part of the vehicle body and that extends in the vehicle width direction with respect to the center of the vehicle width direction of the vehicle body.

The work vehicle may be further provided with a power transmission mechanism and a first partition plate. The power transmission mechanism may transmit the driving power generated by the driving source to the travel device. The power transmission mechanism may be positioned below the work area. The first partition plate may separate the work area and the power transmission mechanism. The first partition plate may have a first inspection port that allows communication from the work area to the power transmission mechanism.

The work vehicle may be further provided with a first cover member that covers the cooling device. The first cover member may have a second inspection port between the work area and the cooling device.

The work vehicle may be further provided with a second cover member that covers the driving source. The second cover member may have a third inspection port between the work area and the driving source. The second cover member may have a third inspection port between the work area and the device to be maintained.

The work area may be surrounded by the cooling device, the device to be maintained, and the fuel tank.

The travel device may have a crawler belt. The cooling device may overlap the crawler belt as seen from above.

A work vehicle according to a second exemplary embodiment of the present invention is provided with a vehicle body, a travel device, a driving source, a work area, and a cover member. The travel device is provided below the vehicle body. The driving source generates driving power for the travel device. The driving source is disposed in a front part of the vehicle body. The work area is provided rearward of the driving source. The cover member covers the driving source. The cover member has a third inspection port that allows communication from the work area to the driving source.

The work vehicle may be further provided with a cooling device disposed to the lateral side of the work area and on one side in the vehicle width direction of the vehicle body.

The work vehicle may be further provided with a power transmission mechanism and a first partition plate. The power transmission mechanism may transmit the driving power generated by the driving source to the travel device. The power transmission mechanism may be positioned below the work area. The first partition plate may separate the work area and the power transmission mechanism. The first partition plate may have a first inspection port that allows communication from the work area to the power transmission mechanism.

The cooling device is disposed on one side in the vehicle width direction of the vehicle body and rearward of the driving source disposed in the front part of the vehicle body in the work vehicle according to the present invention. Therefore, earth and sand do not enter the cooling device from the front during work. Consequently, the work vehicle is able to prevent a reduction in performance of the cooling device.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

First Exemplary Embodiment

Exemplary embodiments of the present invention will be explained in detail with reference to the figures.FIG. 1is a side view of a work vehicle1according to the first exemplary embodiment of the present invention.FIG. 2is a top view of the work vehicle1while a below-mentioned cover6is removed. As illustrated inFIG. 1, the work vehicle1has a travel device2, a vehicle body3, a first work implement4, a second work implement5, and the cover6. The work vehicle1according to the present exemplary embodiment is a vehicle without an operator cab, or more specifically, a bulldozer without an operator cab.

The travel device2is a device for causing the work vehicle1to travel. The work vehicle1is able to carry out work, such as excavation and leveling, by using the first work implement4and the second work implement5. In the present exemplary embodiment, the first work implement4is a blade, for example. The second work implement5is a ripper, for example. As illustrated inFIG. 2, the travel device2has a first crawler belt11and a second crawler belt12. The work vehicle1travels due to the first crawler belt11and the second crawler belt12being driven. The work vehicle1turns by changing the drive speed of the first crawler belt11and the drive speed of the second crawler belt12. The vehicle body3is provided rearward of the first work implement4. The travel device2is provided below the vehicle body3.

In the following explanation, the vehicle width direction is the arrangement direction of the pair of the travel devices2disposed side by side. The forward direction is perpendicular to the vehicle width direction and is the direction from the center of the vehicle body3toward the position where a below-mentioned engine24is disposed. The rearward direction is the direction opposite the forward direction. Left and right refer to the left and right directions while facing in the forward direction. The left and right directions may be paraphrased as the vehicle width direction. Up and down refer to the up and down directions while facing in the forward direction.

In the drawings of the exemplary embodiments, the X-axis positive, direction (+X direction), the X-axis negative direction (−X direction), and the X-axis direction respectively indicate the orientations referred to as the rearward direction, the forward direction, and the front-back direction (or “longitudinal direction”), respectively, of the work vehicle. The Y-axis positive direction (+Y direction), the Y-axis negative direction (−Y direction), and the Y-axis direction respectively indicate the orientations referred to as the right direction, the left direction, and the left-right direction (vehicle width direction or “lateral direction”) of the work vehicle. The Z-axis positive direction (+Z direction), the Z-axis negative direction (−Z direction), and the Z-axis direction respectively indicate the orientations referred to as the upward direction, the downward direction, and the vertical direction of the work vehicle.

When referring toFIG. 2, the work vehicle1is provided with the engine24, an exhaust processing device26, and an after-cooler28. The engine24is, for example, a diesel engine. The engine24is a driving source for generating driving power for driving the travel device2, the first work implement4, and the second work implement5. The driving power generated by the engine24is distributed by a power take-off (PTO) (not illustrated) to a hydraulic pump for driving the first work implement4and the second work implement5, and to a below-mentioned power transmission mechanism36. The exhaust processing device26purifies the exhaust of the engine24. The after-cooler28is the after-cooler of the engine24. The exhaust processing device26and the after-cooler28are disposed higher than the engine24.

The work vehicle1is provided with an engine compartment20covered by a first cladding member20c. The engine compartment20contains the engine24, the exhaust processing device26, and the after-cooler28. The first cladding member20ccovers the engine24, the exhaust processing device26, and the after-cooler28. The engine compartment20is positioned on the front side of the vehicle body3and defines a front part of the vehicle body3. The engine24, the exhaust processing device26, and the after-cooler28are disposed in the front part of the vehicle body3. The upper surface of the first cladding member20cis raised so as to be separated from a below-mentioned first cylinder16aand a second cylinder16b, and the upper end part of the first cladding member20cforms a horizontal plane. The upper end part is referred to as an upper end part UE. The first cladding member20cmay also be referred to as a second cover member.

The after-cooler28is disposed on the rear side of the center Cy in the front-back direction of the engine compartment20. The after-cooler28is a device that requires maintenance by a worker. The after-cooler28may also be referred to as a device to be maintained.

The work vehicle1is provided with the power transmission mechanism36, a hydraulic pump37, and a control valve38. The power transmission mechanism36is connected to the engine24and transmits the driving power generated by the engine24to the travel device2. The power transmission mechanism36includes a transmission, a torque converter, and a steering mechanism, for example. The hydraulic pump37is driven by driving power from the engine24. Hydraulic fluid discharged by the hydraulic pump37is supplied to various types of members (for example, transmission clutches and steering mechanism clutches and brakes) of the power transmission mechanism36via the control valve38. The control valve38controls the hydraulic pressure supplied to the afore-mentioned various members of the power transmission mechanism36. The control valve38is controlled with electrical signals.

As illustrated inFIG. 1, the work vehicle1is provided with a power transmission mechanism compartment30below a first partition plate U1. The power transmission mechanism compartment30is an area that abuts a lower part20bof the engine compartment20and that is surrounded by a vehicle body frame (not illustrated) and the first partition plate U1. The power transmission mechanism compartment30contains the power transmission mechanism36, the hydraulic pump37, and the control valve38.

The work vehicle1is further provided with a first cooling device48. The first cooling device48includes a radiator that cools a coolant for cooling the engine24, for example, and may further include an oil cooler that cools the hydraulic fluid. The first cooling device48is disposed rearward of the engine24and on one side in the vehicle width direction of the vehicle body3. The first cooling device48is positioned on the right side of the center Cx in the vehicle width direction of the vehicle body3. The first cooling device48extends rearward on the rear side of the engine24as seen from above.

As illustrated inFIG. 2, the work vehicle1is provided with a second cladding member40cthat covers the first cooling device48. The area enclosed by the second cladding member40cis referred to as a cooling device compartment40. The cooling device compartment40has a substantially square column shape. The cooling device compartment40is adjacent to the engine compartment20. The cooling device compartment40is disposed to the outside of the engine compartment20in the vehicle width direction. The cooling device compartment40is disposed on one side in the vehicle width direction of the vehicle body3. The cooling device compartment40is positioned to the right of a right end RE of the engine compartment20. The cooling device compartment40extends to the rear on the rear side of a first side surface S1that corresponds with the rear end of the engine compartment20. The second cladding member40cmay also be referred to as a first cover member.

The work vehicle1is provided with a fuel tank50rearward of the first cooling device48. The fuel tank50has a square column shape with a side surface inclined upward and rearward. The fuel tank50abuts a rear end part BE of the cooling device compartment40and extends in the left direction. The fuel tank50is spaced away from the engine compartment20. The fuel tank50is disposed in the end part (rear part) of the rear side of the vehicle body3. The fuel tank50extends in the vehicle width direction relative to the center Cx of the vehicle body3in the vehicle width direction. When referring toFIG. 1, the fuel tank50is disposed above the power transmission mechanism compartment30.

The plane that passes through the upper end part UE of the engine compartment20and extends rearward and in the horizontal direction is defined as a first virtual plane VP1. InFIG. 2, the plane that passes through the right end RE of the engine compartment20and extends rearward and in the vertical direction is defined as a second virtual plane VP2. The plane that passes through a left end LE of the engine compartment20and extends rearward and in the vertical direction is defined as a third virtual plane VP3. The side surface of the fuel tank50on the forward side is a second side surface S2. The first virtual plane VP1, the second virtual plane VP2, and the third virtual plane VP3are depicted as chain double-dashed lines inFIGS. 1 and 2.

A space100enclosed by the first virtual plane VP1, the second virtual plane VP2, the third virtual plane VP3, the first side surface S1, the second side surface S2, and the first partition plate U1is hollow. The space100is referred to as a work area. The vehicle body3has the work area100in a position facing the first cooling device48rearward of the engine24. The work area100is surrounded by the power transmission mechanism compartment30, the cooling device compartment40, the fuel tank50, and a belowmentioned first additional storage compartment55. The work area100is surrounded by the first cooling device48, the after-cooler28, and the fuel tank50.

The work vehicle1further includes a hydraulic fluid tank (not illustrated) and a reducing agent tank (not illustrated) used by the exhaust processing device26. The hydraulic fluid tank and the reducing agent tank are covered by a third cladding member55c. The area enclosed by the third cladding member55cis referred to as the first additional storage compartment55. The first additional storage compartment55has a substantially square column shape.

The first additional storage compartment55is adjacent to the fuel tank50. The first additional storage compartment55extends rearward from behind the rear end S1of the engine compartment20. The first additional storage compartment55is positioned on the left side of the engine compartment20. The first additional storage compartment55is positioned on the left side of the center Cx in the vehicle width direction of the vehicle body3. The first additional storage compartment55is disposed on the other side of the opposite side the one side where the cooling device compartment40is disposed. The first additional storage compartment55is disposed so as to be spaced away from the cooling device compartment40.

When referring toFIG. 1, the first additional storage compartment55is disposed above the power transmission mechanism compartment30. A gap having a distance D in the horizontal direction is provided between the first additional storage compartment55and the engine compartment20. The distance D has, for example, a length of 450 mm or greater which is the passageway width for lateral walking on an earth-moving machinery, as prescribed in ISO 2867. As a result, a worker is able to pass through the gap and enter the work area100. The cover6is formed so as to cover the work area100and block the gap. The upper surface of the cover6is formed along the upper end part UE of the engine compartment20. Ventilation holes6aare provided in the portion of the cover6that blocks the gap. The cover6is removed when a worker carries out maintenance work.

In the present exemplary embodiment, the first additional storage compartment55is depicted as being adjacent to the fuel tank50. However, the first additional storage compartment55may be provided adjacent to the engine compartment20and the gap having the distance D in the horizontal direction may be provided between the first additional storage compartment55and the fuel tank50. In this case as well, the cover6may cover the gap between the first additional storage compartment55and the fuel tank50.

FIG. 3is a perspective view of a work vehicle1according to the first exemplary embodiment. The work vehicle1is depicted with the first work implement4, the second work implement5, and the cover6removed inFIG. 3. The second crawler belt12is depicted schematically. When referring toFIG. 3, the first cladding member20cof the engine compartment20includes a third inspection port21that can be opened and closed on the first side surface S1. The third inspection port21is disposed between the work area100and the engine24and allows communication from the work area100to the engine24.

The after-cooler28is positioned on the reverse side of the third inspection port21. The after-cooler28is disposed between the engine24and the work area100. A worker is able to easily perform maintenance on the after-cooler28by entering the work area100and opening the third inspection port21.

The cooling device compartment40is disposed above the power transmission mechanism compartment30. The second cladding member40cof the cooling device compartment40includes a second inspection port42that can be opened and closed on a third side surface S3. The third side surface S3is the left side surface (side surface facing the center Cx in the vehicle width direction of the vehicle body3) of the cooling device compartment40. The third side surface S3is on the right side (the one side in the vehicle width direction of the vehicle body3discussed above) of the first side surface S1. The first cooling device48is positioned on the reverse side of the second inspection port42. The second inspection port42is positioned between the first cooling device48and the work area100. A worker is able to easily perform maintenance on the first cooling device48by entering the work area100and opening the second inspection port42.

Ventilation holes41are also provided on the third side surface S3. Ventilation holes43are provided on a fourth side surface S4(seeFIG. 2) which is the right side surface (side surface of opposite side in left-right direction from the third side surface S3) of the cooling device compartment40. Consequently, a flow path for outside air is formed from the ventilation holes6aof the cover6to the work area100, the third side surface S3, the first cooling device48, and the fourth side surface S4in this order. Alternatively, a flow path is formed in the reverse order thereof. Because the outside air can more easily pass through the flow path, the cooling performance of the first cooling device48is improved in comparison to the cooling device of a conventional work vehicle.

When referring toFIG. 1, the first partition plate U1separates the work area100and the power transmission mechanism compartment30. When referring toFIG. 2andFIG. 3, the first partition plate U1includes a hatch32that can be opened and closed. The hatch32may be referred to as a first inspection port. The power transmission mechanism36is disposed below the hatch32(that is, below the work area100), and the hatch32allows communication from the work area100to the power transmission mechanism36.

FIG. 4is a view of the vicinity of the hatch32of the work vehicle1according to the first exemplary embodiment. As can be seen, the work area100is provided from the first side surface S1to the second side surface S2in the work vehicle1. A first distance L1that is the distance in the front-back direction between the first side surface S1and the second side surface S2is greater than one half (½ W) of a length W in the front-back direction of the power transmission mechanism36. The first distance L1is 1.5 m or greater and is a value close to the length W in the front-back direction of the power transmission mechanism36.

Conversely,FIG. 5illustrates the vicinity of a hatch in a work vehicle having a conventional cab as a comparative example. As depicted inFIG. 5, a hatch132is provided in a floor surface131of a cab130in the conventional work vehicle. The width L0in the front-back direction of the hatch132is small. The width L0in the front-back direction of the hatch132is shorter than one half (½ W) of the length W in the front-back direction of the power transmission mechanism36. As a result, access to the power transmission mechanism36and the devices (especially the control valve38) accompanied by the power transmission mechanism36from the hatch132is extremely difficult.

The worker is able to easily access the power transmission mechanism36or the hydraulic pump37and the control valve38attached to the power transmission mechanism36by opening the hatch32. The worker enters the work area100and is able to easily perform maintenance on the power transmission mechanism36or the devices accompanied by the power transmission mechanism36.

When referring toFIG. 3, the vehicle body3further includes a first fender13and a second fender14. The first fender13is provided directly above the first crawler belt11. The second fender14is provided directly above the second crawler belt12. The cooling device compartment40is disposed directly above the first fender13. As illustrated inFIG. 2, the cooling device compartment40overlaps the first crawler belt11as seen from above. The first cooling device48overlaps the first crawler belt11.

The first additional storage compartment55is disposed directly above the second fender14. Therefore as illustrated inFIG. 2, the first additional storage compartment55overlaps the second crawler belt12as seen from above. The first crawler belt11is provided on the right side of the vehicle body3and extends in the front-back direction. The second crawler belt12is provided on the left side of the vehicle body3and extends in the front-back direction.

When referring toFIG. 3, the fuel tank50extends from the first fender13to the second fender14. The fuel tank50is disposed so as to cross from the one end to the other end in the vehicle width direction of the vehicle body3. The fuel tank50is positioned in the end part (rear part) of the rear side of the vehicle body3. The vehicle body frame is provided at the end of the vehicle body3. The fuel tank50is supported by the first fender13, the second fender14, and the vehicle body frame. Therefore, even when the fuel tank50is heavy, the fuel tank50can be supported in a stable manner.

When referring toFIG. 1, the second crawler belt12includes a second drive wheel (sprocket)12a, a second driven wheel (idler)12b, a plurality of second carrier rollers12c, and a plurality of track rollers12d. The above members are rotating members that rotate when the second crawler belt12moves. Among the above members, the second driven wheel12bis the rotating member closest to a front end part WFE which is the end part on the front side of the travel device2(second crawler belt12). The second drive wheel12ais the rotating member closest to a rear end part WRE of the travel device2(second crawler belt12). InFIG. 2, the first crawler belt11and the second crawler belt12are symmetrical with respect to the center axis Cx of the vehicle width direction of the vehicle body3, and therefore the first crawler belt11and the second crawler belt12have the same structure.

When referring toFIG. 1, the second side surface S2of the fuel tank50is positioned on the rear side of a front end point P1of the second drive wheel12a. Because the first crawler belt11and the second crawler belt12have the same structure, the second side surface S2of the fuel tank50can also be positioned on the rear side of the front end point of the drive wheel of the first crawler belt11. The driven wheel may be the rotating member closest to the rear end part WRE due to the structures of the first crawler belt11and the second crawler belt12. In this case, the second side surface S2of the fuel tank50is positioned on the rear side of the front end point of the driven wheel which is the rotating member closest to the rear end part WRE.

When referring toFIG. 2, the first work implement4is provided in front of the engine compartment20. The first work implement4includes a blade15and a blade control cylinder16. The blade control cylinder16is a hydraulic cylinder. The blade15is disposed in front of the vehicle body3and is provided in a manner that allows movement in the up-down direction. The blade control cylinder16includes a first cylinder16a, a second cylinder16b, a third cylinder16c, and a fourth cylinder16d.

The first cylinder16aand the second cylinder16bare respectively attached to the corner part in the right front direction and the corner part in the left front direction of the engine compartment20as seen from above. The third cylinder16cand the fourth cylinder16dare connected to the first work implement4and a frame that supports the first work implement4, the frame and the first work implement4being attached to the travel device2. That is, the third cylinder16cand the fourth cylinder16dare attached to the travel device2.

The first cylinder16aand the second cylinder16bare so-called lift cylinders and move the blade15up and down. The third cylinder16cand the fourth cylinder16dare so-called tilt cylinders and control the pitch angle of the blade15. Although not illustrated, the blade15may be configured so that the angle can be changed with an angle cylinder.

The front end part FE of the engine compartment20is positioned on the rear side of the front end part WFE (inFIG. 2, the symbol WFE is attached to the second crawler belt12) of the travel device2. In a conventional bulldozer in which the first cooling device48is disposed on the front side of the engine24, the front end part FE of the engine compartment20is positioned on the front side of the front end part WFE of the travel device2.

When the blade15is disposed in the same position as the conventional manner in the work vehicle1of the present exemplary embodiment, the operating range of the blade15can be increased. For example, the maximum lift amount due to the above-mentioned lift cylinder, the maximum angle change amount due to the angle cylinder, and the maximum pitch back angle due to the tilt cylinder can be increased. The pitch back angle is the rotational angle of the blade15when the blade15is made to rotate in front-back direction of the vehicle.FIG. 6is a view illustrating the maximum pitch back angle of the work vehicle1according to the present exemplary embodiment.FIG. 7is a view illustrating the maximum pitch back amount of a conventional bulldozer. InFIGS. 6 and 7, the standard attitude which is the normal attitude of the blade15is depicted with chain double-dashed lines.

When referring toFIGS. 1 and 6, the fourth cylinder16dincludes a first cylinder connecting part17athat is connected to the blade15and a second cylinder connecting part17bthat is the connecting part on the opposite side from the first connecting part. The second cylinder connecting part17bis positioned rearward of the center of rotation P2of the second driven wheel12b. Conversely, the second cylinder connecting part17bis positioned in front of the center of rotation P2of the second driven wheel12bin the conventional bulldozer inFIG. 7. By positioning the second cylinder connecting part17brearward of the center of rotation P2of the second driven wheel12b, the stroke length in the front-back direction of the fourth cylinder16dcan be made to be longer in the work vehicle1than in the conventional bulldozer.

The positional relationship between the third cylinder16cand the driven wheel of the first crawler belt11is the same as the positional relationship between the fourth cylinder16dand the driven wheel of the second crawler belt12. Therefore, when the blade15is disposed in the same position as the conventional position, the maximum pitch back angle can be increased due to the pitch cylinders16cand16din the work vehicle1of the present exemplary embodiment.

Due to the structures of the first crawler belt11and the second crawler belt12, the drive wheel may be the rotating member closest to the front end part WFE of the travel device2. In this case, the cylinder connecting parts for connecting with the travel device2of the third cylinder16cand the fourth cylinder16d, are positioned rearward of the center of rotation of the drive wheel.

The following incidental effects can be found by increasing the maximum pitch back angle.

InFIGS. 6 and 7, B is a point that represents the blade tip position of the blade15and A is a point that represents a position vertically above the blade tip position of the blade15and the position at the height H that is the upper end of the blade15. C is defined as the angle of repose φ of the earth and sand when the blade15is carrying earth and sand. UB1is a point indicating the upper end of the blade15of the work vehicle1according to the present exemplary embodiment. UB2is a point indicating the upper end of the blade15of the conventional bulldozer.

InFIGS. 6 and 7, θ0represents the angle formed by the blade tip of the blade15with the ground surface while the blade15is in the standard attitude. InFIG. 6, θ1represents the angle formed by the blade tip of the blade15with the ground surface when the pitch angle is at the maximum amount in the work vehicle1. InFIG. 7, 02represents the angle formed by the blade tip of the blade15with the ground surface when the pitch angle is at the maximum amount in the conventional bulldozer. θ0-θ1is the maximum pitch back angle of the work vehicle1and θ0-θ2is the maximum pitch back angle of the conventional bulldozer. As can be seen inFIGS. 6 and 7, the maximum pitch back angle of the work vehicle1(θ0-θ1) is greater than the maximum pitch back angle of the conventional bulldozer (θ0-θ2).

The resistance received by the work vehicle from the earth and sand to be carried is caused by an earth amount Vm enclosed in ABC inFIG. 6orFIG. 7. The portion corresponding to the earth amount Vm is depicted with hatching inFIG. 6andFIG. 7. The earth amount Vm depends upon the height H of the earth and sand to be carried and the angle of repose φ of the earth and sand. The earth amount V1enclosed by ABUB1inFIG. 6and the earth amount V2enclosed by ABUB2inFIG. 7is referred to as the blade holding volume. The portions corresponding to the earth amount V1inFIG. 6and the portion corresponding to the earth amount V2inFIG. 7are represented by a dot pattern.

The maximum pitch back angle of the work vehicle1is larger than that of the conventional bulldozer, and therefore the blade holding volume V1of the work vehicle1can be larger than the blade holding volume V2of the conventional bulldozer. Therefore, the earth amount that can be carried by the blade increases in correspondence to an increase in the size of the maximum pitch back angle. If the height H of the mound formed by the earth amount V were the same as that of the conventional bulldozer, the size of the blade15would need to be larger than that of the conventional blade.

Furthermore, because the front end part FE of the engine compartment20inFIG. 2is positioned to further the rear of the travel device2than that conventional bulldozer, the blade15can be closer to the travel device2than in the case of the conventional bulldozer. Because the blade tip of the blade15can be closer to the gravity center position of the work vehicle1, the excavation force of the work vehicle1can be increased. When the blade15is closer to the travel device2than the conventional case without changing the attachment position of the lift cylinders16aand16b, the lift cylinders16aand16bcan be inclined at an angle closer to the vertical direction. In this case, the force of the lift cylinders16aand16bcan be effectively transmitted to the blade15.

When referring toFIG. 1, the second work implement5is disposed on the rear side of the vehicle body3. Work performed with the second work implement5in the work vehicle1includes piercing stone with a ripper point5battached to the tip of a shank5athat protrudes substantially straight downward, and the stone is broken and pulverized due to the tractive force from the travel device2. Moreover, the second work implement5is driven by hydraulic cylinders (ripper lift cylinder18, ripper tilt cylinder19).

Second Exemplary Embodiment

FIG. 8is a top view of a work vehicle1aaccording to a second exemplary embodiment.FIG. 9is a perspective view of the work vehicle1aaccording to the second exemplary embodiment. The second crawler belt12is depicted schematically inFIG. 9. The illustration of the first cooling device48is omitted inFIG. 9for ease of explanation. The work vehicle1aaccording to the second exemplary embodiment differs in that the exhaust processing device26and the after-cooler28of the work vehicle1according to the first exemplary embodiment are in different positions. Furthermore, the work vehicle1ais provided with an after-cooler storage compartment52that contains the after-cooler28. The shape of the engine compartment20is altered slightly accompanying the above changes.

Other configurations of the work vehicle1aare the same as the configurations of the work vehicle1. Therefore, only the configurations that differ between the work vehicle1aand the work vehicle1will be discussed in the present exemplary embodiment, and other discussions will be omitted.

As can be seen inFIG. 8, a vehicle body3aof the work vehicle1aaccording to the present exemplary embodiment is further provided with a fourth cladding member52cthat covers the after-cooler28. The area enclosed by the fourth cladding member52cis referred to as the after-cooler storage compartment52. The after-cooler storage compartment52contains the after-cooler28. The after-cooler storage compartment52has a substantially square column shape.

The after-cooler storage compartment52abuts an engine compartment20aaccording to the present exemplary embodiment on the right side (on the outside in the vehicle width direction of the engine compartment20a) of the engine compartment20a. The after-cooler storage compartment52extends to the rear on the rear side of the center line Cy in the front-back direction of the engine compartment20a. The rear end of the after-cooler storage compartment52is adjacent to the cooling device compartment40. The first side surface S1of the engine compartment20ais shifted in the forward direction in comparison to the first side surface S1of the engine compartment20of the first exemplary embodiment. The first cooling device48is positioned rearward of the first side surface S1.

The exhaust processing device26is disposed in the engine compartment20aon the rear side of the center Cy in the front-back direction of the engine compartment20a. The exhaust processing device26is disposed toward the rear side of the engine compartment20a. As can be seen inFIG. 9, an opening51is provided at a connection part of the engine compartment20aand the after-cooler storage compartment52. A worker is able to access the after-cooler28from the side of the engine compartment20aby opening the third inspection port21. The worker is able to easily perform maintenance on the after-cooler28by entering the work area100.

Third Exemplary Embodiment

FIG. 10is a top view of a work vehicle1baccording to a third exemplary embodiment of the present invention.FIG. 11is a side view of the work vehicle1b. The work vehicle1baccording to the third exemplary embodiment is not provided with the cover6. The configurations of the cooling device compartment40, the fuel tank50, and the first additional storage compartment55in the third exemplary embodiment differ from the configurations illustrated in the first exemplary embodiment, but other configurations are the same. Only the configurations that differ between the work vehicle1band the work vehicle1will be discussed in the present exemplary embodiment, and other discussions will be omitted.

When referring toFIG. 10, a first cooling device48baccording to the present exemplary embodiment is smaller than the first cooling device48of the first exemplary embodiment. The first cooling device48bextends rearward on the rear side of the first side surface S1as can be seen from above. The first cooling device48bis spaced away from the engine compartment20. The first cooling device48bis disposed in a corner part of the right rear end of a vehicle body3b. The first cooling device48bis disposed in the end part (rear part) of the vehicle body3band is disposed in the end part on the right side of the vehicle body3b.

The first cooling device48boverlaps the first crawler belt11as seen from above. The first cooling device48bis positioned on the right side of the center Cx in the vehicle width direction of the vehicle body3b. The first cooling device48bis disposed rearward of the engine24and on one side in the vehicle width direction of the vehicle body3.

A second cladding member40dfor a cooling device compartment40bcovers the first cooling device48b. The cooling device compartment40bcontains the first cooling device48b. The second cladding member40ddoes not include the second inspection port42. The cooling device compartment40bhas a columnar shape having a side surface40ruthat is inclined upward and rearward. The second cladding member40dof the cooling device compartment40bhas the side surface40ruthat is inclined upward and rearward.

The cooling device compartment40bextends rearward on the rear side of the first side surface S1as can be seen from above. The cooling device compartment40bis spaced away from the engine compartment20. The cooling device compartment40boverlaps the first crawler belt11as seen from above. More specifically, the cooling device compartment40bis disposed in a corner part of the right rear end of a vehicle body3bin the third exemplary embodiment. The cooling device compartment40bis disposed in the end part (rear part) of the vehicle body3band is disposed in the end part on the right side of the vehicle body3b. The cooling device compartment40bis positioned on one side of the center Cx in the vehicle width direction of the vehicle body3b.

The work vehicle1baccording to the present exemplary embodiment further includes a second cooling device56. The second cooling device56includes a radiator that cools a coolant for cooling the engine24, for example, and may further include an oil cooler that cools the hydraulic fluid. The second cooling device56may further include an oil cooler that cools the lubricating oil of the power transmission mechanism36. The second cooling device56is preferably a cooling device that is the same as the first cooling device48bfrom the viewpoint of the weight balance of the work vehicle1b.

The second cooling device56extends rearward on the rear side of the first side surface S1as seen from above. The second cooling device56is spaced away from the engine compartment20. The second cooling device56overlaps the second crawler belt12as seen from above. The second cooling device56is disposed in a corner part of the left rear end of a vehicle body3b. The second cooling device56is disposed in the end part (rear part) of the vehicle body3band is disposed in the end part on the left side of the vehicle body3b.

The second cooling device56is positioned on the left side of the center Cx in the vehicle width direction of the vehicle body3b. The second cooling device56is disposed on the opposite side (other side in the vehicle width direction of the vehicle body3b) of the side where the first cooling device48bis disposed in the vehicle width direction of the vehicle body3b. The second cooling device56is disposed away from the first cooling device48brearward of the engine24.

The second cooling device56is covered by a third cladding member55dof a first additional storage compartment55b. The second cooling device56is stored in the first additional storage compartment55b. The first additional storage compartment55bhas a columnar shape having a side surface55ruthat is inclined upward and rearward. The third cladding member55dhas the side surface55ruthat is inclined upward and rearward. The first additional storage compartment55bextends rearward on the rear side of the first side surface S1as can be seen from above. The first additional storage compartment55bis spaced away from the engine compartment20. The first additional storage compartment55boverlaps the second crawler belt12as seen from above.

The first additional storage compartment55bis disposed in a corner part of the left rear end of a vehicle body3b. The first additional storage compartment55bis disposed in the end part (rear part) of the vehicle body3band is disposed in the end part on the left side of the vehicle body3b. The first additional storage compartment55bis positioned on the left side of the center Cx in the vehicle width direction of the vehicle body3. The first additional storage compartment55bis disposed on the opposite side (other side in the vehicle width direction of the vehicle body3b) of the side where the cooling device compartment40bis disposed in the vehicle width direction of the vehicle body3b. The first additional storage compartment55bis disposed away from the cooling device compartment40brearward of the engine24.

When referring toFIG. 11, the first additional storage compartment55bis disposed above the power transmission mechanism compartment30. The second cooling device56is inclined upward and rearward. Ventilation holes57are formed in the left side surface (side surface of opposite side from surface facing the center Cx on the vehicle width direction of the vehicle body3b) in the first additional storage compartment55b. When referring toFIG. 10, ventilation holes58are formed on the top surface and ventilation holes59are formed in the side surface55ruinclined upward and rearward of the first additional storage compartment55b. The third cladding member55dincludes the ventilation holes57,58, and59. Air drawn in from the ventilation holes57and58is fed to the second cooling device56. The air that has passed through the second cooling device56is exhausted from the ventilation holes59.

FIG. 12is a perspective view of the work vehicle1baccording to the third exemplary embodiment. The second crawler belt12is depicted schematically inFIG. 12. When referring toFIG. 12, the first cooling device48bis also inclined upward and rearward. Furthermore, ventilation holes45are formed on the top surface of the cooling device compartment40band ventilation holes46are formed in the side surface40ruinclined upward and rearward. Additionally, ventilation holes44are formed in the right side surface (side surface of opposite side from surface facing the center Cx on the vehicle width direction of the vehicle body3b) of the cooling device compartment40bas illustrated inFIG. 10The second cladding member40dincludes the ventilation holes44,45and46.

Air drawn in from the ventilation holes44and45is fed to the first cooling device48b. Air that has passed through the first cooling device48bis exhausted from the ventilation holes46.

The work vehicle1bof the present exemplary embodiment is provided with the second work implement (ripper)5. Earth and stones are scattered upward during work with the ripper. However, the possibility of intrusion of pulverized earth and stones from the ventilation holes46and59is low due to the first cooling device48band the second cooling device56being inclined upward and rearward. Therefore, the durability of the first cooling device48band the second cooling device56is improved.

When referring toFIG. 12, a fuel tank50baccording to the present exemplary embodiment also has a square column shape having a side surface that is inclined upward and rearward. When referring toFIG. 10, the fuel tank50bis positioned in the end part (rear part) on the rear side of the vehicle body3b. The fuel tank50bis spaced away from the engine compartment20. The fuel tank50bextends in the vehicle width direction relative to the center Cx of the vehicle body3in the vehicle width direction. The fuel tank50bis disposed above the power transmission mechanism compartment30. The fuel tank50bis disposed between the cooling device compartment40band the first additional storage compartment55b.

A first distance L11which is the distance in the front-back direction between the first side surface S1and the second side surface S2illustrated inFIG. 11, is shorter than the first distances L1depicted in the first exemplary embodiment and the second exemplary embodiment. That is, a work area100bin the third exemplary embodiment is narrower than the work areas100in the first exemplary embodiment and the second exemplary embodiment. As illustrated inFIG. 10, the control valve38is difficult to access even when the hatch32is open. The first distance L11is preferably provided with a distance to allow the third inspection port21to be opened.

The distance between the first additional storage compartment55band the engine compartment20in the third exemplary embodiment is the first distance L11. The distance L11between the first additional storage compartment55band the engine compartment20is greater than a distance L12between the cooling device compartment40band the engine compartment20. In this case, the longer distance L11has, for example, a width of 450 mm or greater which is the passageway width for lateral walking on a construction machine, as prescribed in ISO 2867. Conversely, if the distance L12is greater than the distance L11, the distance L12may be equal to or greater than the afore-mentioned distance.

Fourth Exemplary Embodiment

The fourth and fifth exemplary embodiments discuss configurations of control systems for allowing the work vehicles1,1aand1baccording to the first to third exemplary embodiments to operate as unmanned vehicles. A vehicle control system for allowing the work vehicles1,1a, and1bto be operated remotely will be discussed in the fourth exemplary embodiment.FIG. 13is a block diagram of a control system200. The control system200is provided with an operating terminal8, a communication means9, and a work vehicle10. The work vehicle10represents any one of the work vehicle1according to the first exemplary embodiment, the work vehicle1aaccording to the second exemplary embodiment, and the work vehicle1baccording to the third exemplary embodiment.

The operating terminal8represents a computer or a dedicated terminal for remote control. The operation contents (travel, work implement operations and the like) of the work vehicle10are input by an operator to the operating terminal8. The operating terminal8generates operation commands which are communication data describing the input operation contents, and transmits the operation commands from an operation command transmitter81to the work vehicle10via the communication means9. The communication means9is a communication means for wired communication or for wireless communication such as communication using satellite communication or a mobile telephone network.

The work vehicle10is provided with an operation command receiver65, a control unit70, the work implements4and5, the power transmission mechanism36, the travel device2, and the engine24. The work implements4and5, the power transmission mechanism36, the travel device2, and the engine24are described in detail in the first exemplary embodiment and explanations thereof will be omitted.

The control unit70includes a command analyzing unit71, a work implement controller72, a steering controller73, and an engine controller74. The operation command receiver65receives the operation commands transmitted by the communication means9. The operation command receiver65receives operation commands transmitted from outside of the work vehicle10. When the communication means9is wireless communication, the operation command receiver65includes an antenna function.

The control unit70includes a processor, such as a CPU, a storage device, such as a RAM or a ROM, and controls the work implements4and5and the travel device2according to the operation commands. Typically, programs and data for executing the functions of the command analyzing unit71, work implement controller72, the steering controller73, and the engine controller74are stored in the storage device. The processor executes the programs whereby the control unit70executes the functions of the command analyzing unit71, the work implement controller72, the steering controller73, and the engine controller74. The control unit70may be realized by an integrated circuit.

The command analyzing unit71analyzes the operation commands received by the operation command receiver65and determines the operation amounts of the work implements4and5, and the traveling direction and speed and the like of the travel device2. The work implement controller72determines the operation amounts for the hydraulic cylinders (for example, the first to fourth cylinders16a-16d, the ripper lift cylinder18, the ripper tilt cylinder19) for actuating the work implements4and5, and controls the control valves of the cylinders on the basis of the determined operation amounts of the work implements4and5.

The steering controller73determines the control amounts of the clutches and brakes and the like of the power transmission mechanism36on the basis of the determined traveling direction and speed of the travel device2. The steering controller73determines the hydraulic pressure to be supplied to the clutches and brakes and controls the control valves (for example, the control valve38) related to the clutches and brakes.

The engine controller74calculates the engine horsepower for generating driving power for making the speed of the travel device2achieve the determined speed as well as for the driving power of the hydraulic pump calculated by the work implement controller72. The engine controller74controls the engine24so as to be able to output the horsepower.

The work vehicle10may also be provided with: an environmental sensor, such as a camera, a radar, and an ultrasonic sensor and the like; a positional sensor, such as a GPS and the like; an attitude detecting sensor, such as a gyroscope, an acceleration sensor, and angle sensors for the links to the work implements4and5; and a vehicle information transmitter. The environmental sensor detects the conditions in the vicinity of the work vehicle10. The positional sensor measures the position of the work vehicle10. The attitude detecting sensor measures the attitude of the work vehicle10and the attitudes of the work implements4and5. The vehicle information transmitter transmits the information of the environmental sensor, the positional sensor, and the attitude sensor to the operating terminal8via the communication means9.

The operating terminal8may be further provided with a receiver and a display and the like. The receiver receives the information of the environmental sensor, the positional sensor, and the attitude sensor transmitted by the transmitter. The display displays the information of the environmental sensor, the positional sensor, and the attitude sensor. In this case, an operator is able to transmit operation commands to the work vehicle10remotely without being present at the work site of the work vehicle10.

Fifth Exemplary Embodiment

An example of a vehicular control system of the work vehicles1,1a, and1bfor carrying out excavation and leveling work automatically without commands from an operator will be explained in the fifth exemplary embodiment.FIG. 14is a block diagram of a work vehicle10aaccording to the fifth exemplary embodiment. The work vehicle10arepresents any one of the work vehicle1according to the first exemplary embodiment, the work vehicle1aaccording to the second exemplary embodiment, and the work vehicle1baccording to the third exemplary embodiment.

The work vehicle10ais provided with a design plane data storage unit66, a control unit70a, a work implement state obtaining unit67, the work implements4and5, the power transmission mechanism36, the travel device2, and the engine24. The control unit70aincludes an operation determining unit75, the work implement controller72, the steering controller73, and the engine controller74. Configurations that are the same as in the fourth embodiment will be provided with the same reference numerals and detailed explanations thereof will be omitted.

The design plane data storage unit66stores data of a design plane, which is a work target. The design plane is a three-dimensional design terrain that indicates a target shape to be excavated. The design plane data storage unit66may be realized by an optical disk, such as a CD-ROM, a DVD, or a BD, or by portable memory, such as a memory card or a USB memory. Alternatively, the design plane data storage unit66may be realized by a storage device fixed to the work vehicle10a. When the design plane data storage unit66is a fixed storage device, the work vehicle10ais provided with a communication means or an input means such as wireless communication or serial communication for inputting data of the design plane into the design plane data storage unit66.

The work implement state obtaining unit67obtains the position attitudes of the work implements4and5. The work implement state obtaining unit67includes at least a positional sensor (GPS and the like) and an attitude detecting sensor (gyroscope, acceleration sensor, angle sensor for the links of the work implements4and5, etc.). The positional sensor measures the position of the work vehicle10. The attitude detecting sensor measures the attitude of the work vehicle10and the attitudes of the work implements4and5. The work implement state obtaining unit67calculates the positional relationship between the blade tips of the work implements4and5and the design plane based on the values of the above sensors. Moreover, the work implement state obtaining unit67may calculate the angle formed by the blade tips of the work implements4and5and the design plane based on the values of the above sensors.

The operation determining unit75controls the positional attitudes of the work implements4and5so that the blade tips of the work implements4and5follow the design plane, and makes the travel device2travel in the direction and speed appropriate for the design plane. The operation determining unit75determines the operation amounts of the work implements4and5and traveling direction and speed and the like of the travel device2. Specifically, when the distance between the blade tips of the work implements4and5and the design plane is judged to be equal to or less than a predetermined threshold in accordance with the speed of the travel device2, the blade is controlled to move upward as indicated in U.S. Pat. No. 5,167,1403, for example.

Alternative Exemplary Embodiments

Although the exemplary embodiments of the present invention have been described so far, the present invention is not limited to the above exemplary embodiments and various modifications may be made within the scope of the invention.

The present invention is not limited to the above-mentioned bulldozer and may be applied to another type of work vehicle, such as a wheel loader, a forklift, or a motor grader.

The work vehicles1,1b,1c,10, and10amay be provided with a driving source, such as an electric motor in place of the engine24. Alternatively, a hybrid driving source in which the engine24and an electric motor are combined may also be used. At least one of the driving sources may be stored in the engine compartment20in the work vehicles1,1b,1c,10or10aprovided with the hybrid driving source.

The work areas100and100bmay be prescribed as a space narrower than the space enclosed by the first virtual plane VP1, the second virtual plane VP2, the third virtual plane VP3, the first side surface S1, the second side surface S2, and the first partition plate U1is hollow. For example, the work areas100and100bmay be prescribed by the rotational range of the door the third inspection port21, or the space above the hatch32may be defined as the work areas100and100b.

The ventilation holes6a,41,44,45,46,57,58, and59depicted in the drawings of the above exemplary embodiments are merely examples and may have other shapes. The shapes and functions of the first work implement4, the second work implement5, the first crawler belt11, and the second crawler belt12are similarly not limited by the drawings of the above exemplary embodiments.

The characteristics of the work vehicle disclosed by the present description are as follows.

The engine24is disposed in the front part of the vehicle bodies3,3aand3bin the work vehicles1,1aand1b. The first cooling devices48and48bare disposed rearward of the engine24and on one side in the vehicle width direction of the vehicle bodies3,3a, and3b. Therefore, the inflow of earth and sand (for example, earth and sand leaking downward from the upper surface of the first work implement4) from the ventilation holes of the first cooling device48during work can be limited. Consequently, the work vehicles1,1aand1bare able to prevent a reduction in the performance of the first cooling device48.

The vehicle bodies3and3ahave the work area100in a position facing the first cooling device48rearward of the engine24. Therefore, maintenance of the first cooling device48is facilitated.

The after-cooler28is disposed between the engine24and the work area100. Therefore, maintenance of the after-cooler28is facilitated.

The fuel tanks50and50bare disposed in the rear part of the vehicle bodies3,3aand3band extend in the vehicle width direction with respect to the center in the vehicle width direction of the vehicle bodies3,3aand3b. The vehicle body frame is provided at the end of the vehicle bodies3,3aand3b. Therefore, the fuel tank50can be supported in a stable manner.

The first partition plate U1which separates the work area100and the power transmission mechanism36has the hatch32(first inspection port). Therefore, maintenance of the power transmission mechanism36can be performed easily by opening the hatch32.

The second cladding member40c(first cover member) has the second inspection port42between the work area100and the first cooling device48. Therefore, access from the work area100to the first cooling device48is facilitated.

The first cladding member20c(second cover member) has the third inspection port21between the work area100and the engine24. Therefore, access from the work area100to the after-cooler28and the exhaust processing device26is facilitated.

The first cladding member20c(second cover member) has the third inspection port21between the work area100and the after-cooler28. Therefore, maintenance of the after-cooler28from the work area100is further facilitated.

The first cooling device48overlaps the first crawler belt11in the first to third exemplary embodiments. Therefore, the distance of the work area100in the vehicle width direction can be increased. Consequently, the hatch32(first inspection port) can be widened. As a result, maintenance on the power transmission mechanism36and the devices (for example, the control valve38) accompanied by the power transmission mechanism36is further facilitated. Moreover, a large amount of air can be drawn into the first cooling device48and the cooling efficiency of the first cooling device48is improved.

According to the present invention, there is provided a work vehicle in which the cooling device is disposed in a new location so that a reduction in the performance of the cooling device can be prevented.