Work vehicle

Abstract

Provided is a work vehicle in which a seat support frame that supports a driver seat is equipped on a vehicle body frame, the vehicle body frame includes: a front portion vehicle frame at which a floor surface of a driving portion is provided; and a rear portion vehicle frame disposed at a position higher than the floor surface of the driving portion and rearward of the front portion vehicle frame. An engine is equipped below the rear portion vehicle frame, a battery that supplies power to an electric motor is equipped above the front portion vehicle frame and below the seat support frame, and a frame portion of the seat support frame that exists above the battery at a position opposing the battery is configured to be detachable from another frame portion that is fixed to the vehicle body frame.

Claims

1. A work vehicle, comprising: a traveling apparatus; an electric motor configured to drive the traveling apparatus; a battery configured to supply power to the electric motor; a cover member that supports a driver seat mounted thereon and includes a housing space in its interior; a cooling fan configured to supply a cooling wind into the housing space to cool the battery; a vehicle speed sensor configured to detect a vehicle speed; and a control device configured to control driving of the cooling fan, wherein the control device is configured to drive the cooling fan based on a detection value of the vehicle speed sensor, wherein the control device includes a traveling state determination unit configured to determine whether a vehicle is in a traveling state or a stopped state based on the detection value of the vehicle speed sensor, and a cooling fan driving unit configured to drive the cooling fan based on the determination result of the traveling state determination unit, wherein, when in the stopped state, the vehicle is not driving, and the cooling fan driving unit is configured to drive the cooling fan only if the vehicle is in the stopped state, and the cooling fan driving unit does not drive the cooling fan if the vehicle is in the traveling state, wherein the battery and the cooling fan are arranged in the housing space, wherein a ventilation opening is provided in a front wall portion of the cover member, wherein the cooling fan is attached at the ventilation opening at a position adjacent the housing space, wherein a recessed portion that is upwardly recessed is formed on a lower surface portion of the battery, and wherein the battery and the electric motor are aligned to each other in a vertical direction, with an upper portion of the electric motor entering the recessed portion.

2. The work vehicle according to claim 1, wherein the ventilation opening is provided in a front wall portion of the cover member.

3. A work vehicle, comprising: a traveling apparatus; an electric motor configured to drive the traveling apparatus; a battery configured to supply power to the electric motor; and a cover member that supports a driver seat mounted thereon and includes a housing space in its interior; a cooling fan configured to supply a cooling wind into the housing space to cool the battery; wherein the battery and the cooling fan are arranged in the housing space, a ventilation opening is provided in a front wall portion of the cover member, and the cooling fan is attached at the ventilation opening at a position adjacent the housing space, wherein a recessed portion that is upwardly recessed is formed on a lower surface portion of the battery, and wherein the battery and the electric motor are aligned to each other in a vertical direction, with an upper portion of the electric motor entering the recessed portion.

4. The work vehicle according to claim 3, further comprising: a vehicle speed sensor configured to detect a vehicle speed; and a control device configured to control driving of the cooling fan, wherein the control device drives the cooling fan based on a detection value of the vehicle speed sensor.

5. The work vehicle according to claim 4, wherein the control device includes a traveling state determination unit configured to determine whether a vehicle is in a traveling state or a stopped state based on the detection value of the vehicle speed sensor, and a cooling fan driving unit configured to drive the cooling fan based on the determination result of the traveling state determination unit, and wherein, when in the stopped state, the vehicle is not driving, and the cooling fan driving unit is configured to drive the cooling fan only if the vehicle is in the stopped state, and, the cooling fan driving unit does not drive the cooling fan if the vehicle is in the traveling state.

6. The work vehicle according to claim 4, wherein the control device includes a traveling state determination unit configured to determine whether the work vehicle is in a traveling state or a stopped state based on the detection value of the vehicle speed sensor, and a cooling fan driving unit configured to drive the cooling fan based on the determination result of the traveling state determination unit, and wherein if the vehicle is in the traveling state, the cooling fan driving unit drives the cooling fan when the detection value of the vehicle speed sensor is not more than a reference value.

7. The work vehicle according to claim 6, wherein in a region in which the detection value of the vehicle speed sensor is not more than the reference value, the cooling fan driving unit drives the cooling fan at a higher rotation rate the lower the detection value of the vehicle speed sensor is.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a left-side view of a multi-purpose work vehicle.

(2) FIG. 2 is a plan view of the multi-purpose work vehicle.

(3) FIG. 3 is a rear view of the multi-purpose work vehicle.

(4) FIG. 4 is a left-side view showing a vehicle body frame and a motive power portion in a rear half portion of the multi-purpose work vehicle.

(5) FIG. 5 is a plan view showing a vehicle body frame and a motive power portion in a rear half portion of the multi-purpose work vehicle.

(6) FIG. 6 is a front view showing a portion below a driver seat and an under-seat space, as viewed from the front surface side of the driver seat.

(7) FIG. 7 is a front view showing a below-seat space, as viewed from the front surface side of the driver seat.

(8) FIG. 8 is an exploded perspective view of a seat support frame and a below-seat space.

(9) FIG. 9 is a cross-sectional view taken along line IX-IX in FIG. 4.

(10) FIG. 10 is a perspective view showing a state of assembling a main frame and a motive power portion support frame.

(11) FIG. 11 is an exploded perspective view showing the motive power portion support frame.

(12) FIG. 12 is a perspective view showing a state in which an engine and an electric motor are incorporated in the motive power portion support frame.

(13) FIG. 13 is a drawing illustrating detaching and attaching a laterally-oriented frame in the seat support frame.

(14) FIG. 14 is a cross-sectional view showing a coupling structure for a laterally-oriented frame in the seat support frame.

(15) FIG. 15 is a perspective view showing a coupling structure at the main frame and a front portion of the motive power portion support frame.

(16) FIG. 16 is a perspective view showing a coupling structure at the main frame and a rear portion of the motive power portion support frame.

(17) FIG. 17 is a left-side view showing a utility vehicle.

(18) FIG. 18 is a plan view showing a utility vehicle.

(19) FIG. 19 is a left-side cross-sectional view showing a vehicle body rear half portion.

(20) FIG. 20 is a front cross-sectional view showing a driving portion.

(21) FIG. 21 is a diagram showing control blocks of a control device.

(22) FIG. 22 is a diagram showing a control flow of a control device.

(23) FIG. 23 is a schematic diagram showing a heat blocking structure of a battery.

(24) FIG. 24 is a diagram showing a control flow of a control device according to another embodiment.

DETAILED DESCRIPTION

First Embodiment

(25) Hereinafter, an example of an embodiment for a work vehicle according to the present invention will be described with reference to the drawings.

(26) Note that the front-rear direction and the left-right direction in the description of the present embodiment are written as follows, as long as there is no particular description otherwise. That is, the direction of advancing to the forward side (see arrow F in FIG. 2) at the time of work travel of a traveling vehicle body, such as a multi-purpose work vehicle to which the present invention has been applied, is front, the direction of advancing to the rearward side (see arrow B in FIG. 2) is rear, and using a front-facing orientation in the front-rear direction as a reference, the direction corresponding to the right side (see arrow R in FIG. 2) is right, and similarly, the direction corresponding to the left side (see arrow L in FIG. 2) is left.

(27) Overall Configuration

(28) FIGS. 1 to 3 show a multi-purpose work vehicle serving as an example of a work vehicle.

(29) In the multi-purpose work vehicle, a left and right pair of front wheels 4F, 4F that can be steered are supported on the front portion of a vehicle body frame 1, which forms a framework for a traveling vehicle body. A left and right pair of rear wheels 4R, 4R that cannot be steered are supported on the rear portion of the vehicle body frame 1. Drive power can be transmitted from later-described traveling output apparatuses to the front wheels 4F, 4F and the rear wheels 4R, 4R. Accordingly, the multi-purpose work vehicle is constituted by a four-wheel-travel four-wheel-drive vehicle.

(30) A driving portion 2 including a steering wheel 21 and a driver seat 22 is provided at an intermediate portion in the front-rear direction of the traveling vehicle body.

(31) A cargo bed 5 that performs a dumping operation with the rear end side used as a swinging fulcrum x1 is equipped rearward of the driving portion 2, and a partitioning member 18 that partitions the driving portion 2 and the cargo bed 5 (constitutes a rear wall of the driving portion 2) is disposed between the driving portion 2 and the cargo bed 5.

(32) The cargo bed 5 is configured to perform a dumping operation using an electric hydraulic cylinder 11 provided between the cargo bed 5 and a later-described motive power portion support frame 30 in the vehicle body frame 1. Also, left and right front fenders 12 and a hood 13 are included in the front portion of the multi-purpose work vehicle.

(33) The motive power portion 3 is provided at the rear portion of the traveling vehicle body in a state of being located below the cargo bed 5.

(34) Traveling output apparatuses of two systems, namely a gasoline engine 6 (hereinafter simply abbreviated as engine), which is an internal combustion engine, and an electric motor 8 are provided in the motive power portion 3.

(35) In the traveling output apparatuses of the two systems, the power of the engine 6 is transmitted to the rear wheels 4R via rear axles 14 (corresponds to a power transmission axle) that extend in a left-right lateral orientation from a transmission case 7 in which a transmission (not shown) is included. The power of the electric motor 8 is input to a front wheel differential case 16 by the front wheel transmission shaft 15 extending forward from the front end portion of the electric motor 8, and the power is transmitted to the front wheels 4F via left and right front axles 17.

(36) A ROPS frame 20 that surrounds the driver seat 22 in which a driver sits and a passenger seat 23 in which another passenger sits, and forms a riding space s1 is included in the driving portion 2. Accordingly, occupants sitting in the driver seat 22 and the passenger seat 23 are located in the riding space s1 surrounded by the ROPS frame 20.

(37) As shown in FIGS. 4 to 6, below the riding space s1 surrounded by the ROPS frame 20, a below-seat space s2 corresponding to the lower side of the driver seat 22 and the passenger seat 23 is used as a space for disposing a fuel tank 34 for supplying fuel to the engine 6, and a battery 9 for supplying power to the electric motor 8.

(38) The under-seat space s2 is used also so that the electric motor 8 attached to the motive power portion support frame 30 supporting the engine 6 is equipped in a state of being in the under-seat space s2. The specific configuration relating to the disposition of the electric motor 8 attached to the motive power portion support frame 30 will be described later.

(39) Vehicle Body Frame

(40) As shown in FIGS. 1, 4, and 8, a vehicle body frame 1 includes a front portion vehicle frame 1A disposed so as to support a floor surface of the driving portion 2, and a rear portion vehicle frame 1B disposed at a position higher than the floor surface of the driving portion 2. The rear portion vehicle frame 1B is located rearward of the front portion vehicle frame 1A, and the front portion vehicle frame 1A and the rear portion vehicle frame 1B are configured integrally with each other.

(41) Specifically, the vehicle body frame 1 includes a left and right pair of main frames 10 that are elongated in the front-rear direction. The main frame 10 includes a front portion frame 10A, a rear portion frame 10C, and a standing leg portion 10B that is located between and connects the front portion frame 10A and the rear portion frame 10C, whereby the main frame 10 is formed into a step shape whose frontward side is lower and whose rearward side is higher. The left and right main frames 10 are integrated by being coupled by horizontal rail members 10D at multiple locations in the front-rear direction.

(42) The main frame 10 is provided in a range spanning over the entirety of the front portion vehicle frame 1A and the rear portion vehicle frame 1B in the front-rear direction. In the main frame 10, the front portion frame 10A is a framework for the front portion vehicle frame 1A, and the rear portion frame 10C is the framework for the rear portion vehicle frame 1B. At an intermediate position between the front portion vehicle frame 1A and the rear portion vehicle frame 1B, the standing leg portion 10B joins the front portion frame 10A and the rear portion frame 10C so as to integrate them.

(43) As shown in FIGS. 1 and 2, the front portion vehicle frame 1A supports the left and right front wheels 4F via left and right front suspensions (not shown). The motive power portion support frame 30 is fixed to the lower side of the rear portion vehicle frame 1B, and the left and right rear wheels 4R are supported on the motive power portion support frame 30 via left and right rear suspensions 4A.

(44) The motive power portion support frame 30 is for fulfilling the role of forming the motive power portion 3 below the rear portion vehicle frame 1B in addition to supporting the rear wheels 4R as described above, and constitutes a portion of the vehicle body frame 1. In other words, the motive power portion support frame 30 is configured to be able to join to the main frame 10, spanning between the rear end portion of the front portion vehicle frame 1A and the rear end portion of the rear portion vehicle frame 1B, and constitutes a portion of the vehicle body frame 1 when joined to the main frame 10. However, the motive power portion support frame 30 is configured to be detachable from the main frame 10.

(45) Motive Power Portion Support Frame

(46) The motive power portion support frame 30 includes an engine-side frame portion 40 on which an engine 6 and a transmission case 7 are mounted, and a motor-side frame portion 50 on which the electric motor 8 is mounted, and is constituted as follows.

(47) As shown in FIGS. 4, 5, and 10 to 12, the front end portion of the engine-side frame portion 40 is configured to be joinable to the rear end portion of the front portion frame 10A at the rear end portion of the front portion vehicle frame 1A. The rear end portion of the engine-side frame portion 40 is configured to be joinable to the rear portion frame 10C at the rear end portion of the rear portion vehicle frame 1B.

(48) The rear end portion of the motor-side frame portion 50 is joined to the front end portion of the engine-side frame portion 40 and the front end portion of the motor-side frame portion 50 is detachably joined to the front portion vehicle frame 1A at a location that is forward of the location at which the rear end portion of the front portion vehicle frame 1A and the front end portion of the engine-side frame portion 40 are joined.

(49) The thus-configured engine-side frame portion 40 and motor-side frame portion 50 are configured to be detachable from the main frame 10 when joined together integrally.

(50) The engine-side frame portion 40 will be described next.

(51) As shown in FIGS. 5 and 11, the engine-side frame portion 40 includes a left and right pair of front-rear direction frames 41, which are integrally connected at their front end sides, rear end sides, and intermediate positions by horizontal members 42. The left and right front-rear direction frames 41 are constituted by rectangular pipe materials with rectangular cross sections. The rectangular pipe members are bent at intermediate positions in the front-rear direction, are formed such that the left-right direction interval on the rear side is narrower than the left-right direction interval on the front side, and thus are configured such that interference with the rear wheels 4R is avoided. The left-right direction interval on the front end side of the front-rear direction frame 41 is formed to be a left-right direction interval that is about the same as that at the rear end portion of the front portion frame 10A of the main frame 10.

(52) A gutter-shaped bracket portion 43 for joining the front end portion of the engine-side frame portion 40 to the rear end portion of the front portion frame 10A is attached to the front end portion of the engine-side frame portion 40. Suspending members 45 for joining the rear end portion of the engine-side frame portion 40 to the rear end side of the rear portion frame 10C are attached at the rear end portion of the engine-side frame portion 40.

(53) The upper end sides of the suspending members 45 are configured to be wider in the left-right direction such that the upper end sides can be joined to the left and right rear portion frames 10C, the lower end sides are configured to be narrower in the left-right direction due to the lower end sides being joined to the front-rear direction frames 41 of the engine-side frame portion 40, and thus the suspending members 45 are formed in a downwardly-tapering shape in a view in the front-rear direction.

(54) As shown in FIG. 15, the front end portion of the engine-side frame portion 40 is joined to the rear end portion of the front portion frame 10A via the gutter-shaped bracket portions 43 for joining, which are included on the front end portion of the engine-side frame portion 40.

(55) The gutter-shaped bracket portions 43 are formed into gutter shapes whose upper sides are open, and are fixed by welding to the engine-side frame portion 40 in a state of embracing the front end portion of the engine-side frame portion 40 from below. Also, bolt insertion holes 43b are formed on lateral plate portions 43a of the gutter-shaped bracket portions 43, which protrude upward past the upper edges of the engine-side frame portion 40.

(56) The gutter-shaped bracket portions 43 are attached from the lower side of the front portion frame 10A in a state in which the lateral plate portions 43a embrace the rear end portions of the front portion frames 10A from both the left and right sides. Bolt insertion holes 10Aa, which are formed on the rear end portions of the front portion frames 10A in this state, are lined up with the bolt insertion holes 43b formed on the lateral plate portions 43a, joining bolts 44 are inserted into the bolt insertion holes 10Aa and 43b from the left-right direction and are fastened, and the rear end portions of the front portion frames 10A are interposed between the lateral plate portions 43a from both the left and right sides, and are thus joined and fixed.

(57) The rear end portion of the engine-side frame portion 40 is joined in the following manner to the rear end portion of the rear portion vehicle frame 1B.

(58) As shown in FIGS. 10 to 12 and 16, the lower end portions of the suspending members 45, whose upper end portions can be joined to the rear portion frames 10C at the rear end portion of the rear portion vehicle frame 1B, are fixed by welding to the rear end portion of the engine-side frame portion 40.

(59) Backing plates 46 for joining are fixed by welding to the upper end portions of the suspending members 45. The backing plates 46 for joining include upward-facing abutting surfaces 46a that include bolt insertion holes 46b. Attachment brackets 47 that include downward-facing lower surfaces 47a are fixed by welding to lateral side surface portions facing the vehicle body inward side, on the lateral side surfaces of the rear portion frames 10C. Bolt insertion holes 47b are formed in the attachment brackets 47 as well.

(60) The bolt insertion holes 46b included in the backing plates 46 for joining and the bolt insertion holes 47b included in the attachment brackets 47 are lined up and are fastened by inserting joining bolts 48 in the vertical direction into the bolt insertion holes 46b and 47b. Thus, the upper end portions of the suspending members 45 are detachably fixed by joining to the rear portion frames 10C.

(61) A motor-side frame portion 50 will be described next.

(62) As shown in FIGS. 5, 8, and 11, the motor-side frame portion 50 includes a left and right pair of front-rear direction frames 51 constituted by downwardly-opening members that are channel-shaped in cross section. The motor-side frame portion 50 includes the front-rear direction frames 51 and a front and rear pair of horizontal members 52 that connect the front end sides and rear end sides of the front-rear direction frames 51, and thus the motor-side frame portion 50 is formed into a rectangular frame shape in plan view.

(63) The width in the left-right direction of the front-rear direction frames 51 in the motor-side frame portion 50 is formed to be narrower than the interval in the left-right direction between the front portion frames 10A in the main frame 10, and the motor-side frame portion 50 is arranged in a state of being located between the left and right front portion frames 10A.

(64) A left and right pair of joining brackets 52a that overlap with a left and right pair of attachment seat portions 42a included on the horizontal member 42 on the front end side of the engine-side frame portion 40 are provided on the horizontal member 52 on the rear end side of the motor-side frame portion 50. The joining brackets 52a and the attachment seat portions 42a are fastened due to joining bolts 53 being inserted therein, whereby the rear end side of the motor-side frame portion 50 is configured to be integrally joinable to the engine-side frame portion 40.

(65) The front end side of the motor-side frame portion 50 is configured to be detachable from joining members 54 attached to the horizontal rail member 10D provided horizontally between the front portion frames 10A in the main frames 10. In other words, joining holes 51a are formed on the upper surface sides of the front end portions of the front-rear direction frames 51 of the motor-side frame portion 50, and lock nuts (not shown) are fixed on the under surface sides of the front-rear direction frames 51 at the regions at which the joining holes 51a are formed. Accordingly, the joining holes 51a of the front-rear direction frames 51 are positioned in a state of being in alignment with joining holes (not shown) formed in the joining members 54, whereby fixing by joining can be achieved by tightening the joining bolts 55, or joining can be removed by loosening the joining bolts 55.

(66) The locations at which the joining members 54 and the front end portions of the front-rear direction frames 51 are joined are set to be locations that are located more forward in the front-rear direction of the vehicle body frame 1 than the locations at which the rear end portions of the front portion frames 10A and the front end portion of the engine-side frame portion 40 are joined.

(67) Also, the motor-side frame portion 50 is arranged not above the upper edges 10Ab of the front portion frames 10A, but as shown in FIG. 9, is arranged in a state in which the upper edges 51b of the front-rear direction frames 51 are located slightly lower than the upper edges 10Ab of the front portion frames 10A, and the lower edges 51c of the front-rear direction frames 51 and the lower edges 10Ac of the front portion frames 10A are at approximately the same height. Thus, due to the front-rear direction frames 51 being arranged at lower positions so as to be located within the vertical width of the front portion frames 10A, it is easier to arrange the electric motor 8 at a low position on the vehicle body frame 1.

(68) Multiple fixing platforms 56 (corresponding to motor support portions) for joining and fixing the electric motor 8 are provided in a standing manner on the upper surface sides of the front-rear direction frames 51 of the motor-side frame portion 50, and the electric motor 8 is fixed to the front and rear fixing platforms 56 by inserting joining bolts 57 into attachment portions provided in the periphery of the electric motor 8.

(69) When attached to the motor-side frame portion 50, the lower edge of the electric motor 8 is located lower than the upper edges 10Ab of the front portion frames 10A of the main frame 10, and is located above the lower edges of the front portion frames 10A (see FIG. 6).

(70) Seat Support Frame

(71) Next, a seat support frame 24 will be described.

(72) As shown in FIGS. 4 and 7, the seat support frame 24 is below the riding space s1 surrounded by the ROPS frame 20, is for supporting the driver seat 22 and the passenger seat 23, and is for forming the below-seat space s2 below the driver seat 22 and the passenger seat 23.

(73) As shown in FIG. 6, the below-seat space s2 is used as a space for arranging the fuel tank 34 for supplying fuel to the engine 6, the battery 9 for supplying power to the electric motor 8, and various types of electrical devices 37 for control, and the below-seat space s2 is used also as a location for ensuring space for housing the electric motor 8.

(74) As shown in FIG. 8, the seat support frame 24 includes a left and right pair of front-facing frames 25 that extend forward from the upper portions of the left and right standing leg portions 10B of the main frames 10, a left and right pair of upright frames 26 that are provided in a standing manner on the upper surface side of the left and right front portion frames 10A, and a laterally-oriented frame 27 that is arranged in the left-right direction in a state of connecting the intersection portions of the front-facing frames 25 and the upright frames 26.

(75) A seat attachment platform (not shown) is mounted above the seat support frame 24, and the driver seat 22 and the passenger seat 23 are fixed to the seat attachment platform.

(76) As shown in FIG. 6, in the below-seat space s2 formed below the seat support frame 24, a tank support platform 34A is extended toward the right side (shown on the left side in FIG. 6) of the right-side front portion frame 10A, and the fuel tank 34 is arranged above the tank support platform 34A.

(77) On the left side (shown on the right side in FIG. 6) of the left-side front portion frame 10A, various types of electrical devices 37 for control are equipped via appropriate attachment members joined to the laterally-oriented frame 27 of the seat support frame 24, so as to be located laterally outside of the front portion frame 10A.

(78) As the battery 9 for supplying power to the electric motor 8, a lithium ion battery is included between the left and right front portion frames 10A in the below-seat space s2.

(79) As shown in FIGS. 7 to 9, the battery 9 is formed into a shape having a level difference in which the height on the lower surface side is different on the left and on the right. A higher lower surface 9a, which is on the right side, is fixed to a taller right attachment platform 35R, which is provided in a standing manner on the right-side front portion frame 10A, and a lower lower surface 9b, which is on the left side, is attached to a shorter left attachment platform 35L, which is provided in a standing manner on the left-side front portion frame 10A.

(80) Among the lower surfaces 9a and 9b with different heights, the left-right direction length of the higher lower surface 9a on the right side is formed to be longer than the left-right direction length of the lower lower surface 9b on the left side, and the electric motor 8 mounted on the motor-side frame portion 50 of the motive power portion support frame 30 is disposed in the space below the higher lower surface 9a on the right side in a state of being in the space, or in other words, in a state of overlapping with the battery 9 in the front-rear direction and the left-right direction.

(81) Thus, the battery 9 and the electric motor 8 overlap in the front-rear direction and in the left-right direction, and moreover, the upper portion of the electric motor 8 is disposed in a state of being below the higher lower surface 9a on the right side of the battery 9, whereby the battery 9, the electric motor 8, and an aggregate consisting of the battery 9 and the electric motor 8 are mounted in a state of being consolidated near a central position in the front-rear direction and the left-right direction of the traveling vehicle body.

(82) In other words, the battery 9 and the electric motor 8 are located between the left and right front portion frames 10A in the left-right direction, and are located between the front axles 17 and the rear axles 14 in the front-rear direction. Furthermore, in the front-rear direction, the battery 9 and the electric motor 8 exist in the below-seat space s2, which is a location that is nearer to the central position.

(83) Also, in the vertical direction as well, the battery 9 and the electric motor 8 are provided at a low position on the vehicle body frame 1.

(84) In other words, the battery 9 is attached via the right attachment platform 35R and the left attachment platform 35L to the front portion frame 10A at a low position in the vehicle body frame 1. Also, the motor-side frame portion 50 includes the front-rear direction frames 51, which have upper edges 51b at positions lower than that of the upper edges 10Ab of the front portion frames 10A, and the electric motor 8 is mounted on the front-rear direction frames 51. By thus arranging the motor-side frame portion 50 as low as possible on the traveling vehicle body, the height of disposing the electric motor 8 in the traveling vehicle body is made as low as possible.

(85) In addition to this, by disposing the electric motor 8 in a state of being below the higher lower surface 9a of the battery 9, which has a level difference on its lower surface side, a state is entered in which the battery 9 and the electric motor 8 overlap in the vertical direction as well. Accordingly, the height position of the center of gravity G2 can be set to a position that is as low as possible in the traveling vehicle body for the aggregate consisting of the battery 9 and the electric motor 8.

(86) As a result, as shown in FIG. 7, in a multi-purpose work vehicle, which includes a sturdy ROPS frame 20, and in which the position of the center of gravity G1 of the overall traveling vehicle body tends to be comparatively high, the height position of the center of gravity G2 of the aggregate consisting of the battery 9 and the electric motor 8 is lower than the height position of the center of gravity G1 of the overall traveling vehicle body. In other words, the above-described arrangement configuration of the battery 9 and the electric motor 8 serves as a means for making the height of the center of gravity G1 of the overall traveling vehicle body lower.

(87) Note that the center of gravity G1 of the overall traveling vehicle body in this context refers to the position of the center of gravity G1 of the overall traveling vehicle body in a state in which the battery 9 and the electric motor 8 are mounted on the vehicle body frame 1.

(88) In the seat support frame 24, the laterally-oriented frame 27, which extends in the left-right direction, can be divided at two locations between the left and right front portion frames 10A, the locations being separated slightly on the vehicle body inner side with respect to the intersection portions of the left and right front-facing frames 25 and the upright frames 26.

(89) The purpose of this is to, in the case of employing a configuration in which a portion of the battery 9 is disposed in a state of being below the laterally-oriented frame 27, make it possible to detach a portion of the laterally-oriented frame 27 at a location opposing the position at which the battery 9 exists, thus making it easier to lift and lower the battery 9 without hindrance.

(90) Specifically, as shown in FIGS. 7 and 8, the rectangular pipe-shaped laterally-oriented frame 27 is constituted by a combination of a detachable frame portion 28 (corresponds to a frame portion) that is detachable, and fixed frame portions 29 (correspond to another frame portion) that are not detachable.

(91) The fixed frame portions 29 are fixed to the vehicle body frame 1 due to the vicinities of the end portions on the vehicle body inward side being joined to the intersection portions between the front-facing frames 25 and the upright frames 26, and due to the vicinities of the end portions on the vehicle body outward sides being joined to outside leg frames 38 and handrail frames 39, which are provided on the vehicle body outward side with respect to the front portion frames 10A.

(92) The detachable frame portion 28 is merely configured such that both end portions thereof are joinable to the left and right fixed frame portions 29, and is not joined at other regions.

(93) The detachable frame portion 28 and the fixed frame portions 29 are joined as follows.

(94) As shown in FIGS. 13 and 14, the detachable frame portion 28 and the fixed frame portions 29 are constituted by fitting rectangular column-shaped connecting metal parts 28b and 29b on the end portions of rectangular pipe-shaped frame tubes 28a and 29a so that they are fixed integrally.

(95) Among the connecting metal parts 28b and 29b, the connecting metal part 29b on the fixed frame portion 29 side has a shape obtained by cutting out an upper half portion on the end portion opposing the detachable frame portion 28. The connecting metal part 28b on the detachable frame portion 28 side has a shape obtained by cutting out a lower half portion on the end portion opposing the fixed frame portion 29 side.

(96) Also, the connecting metal part 28b on the detachable frame portion 28 having the shape obtained by cutting out the lower half portion is overlapped with the upper side of the connecting metal part 29b on the fixed frame portion 29 having the shape obtained by cutting out the upper half portion, and the connecting metal parts 28b and 29b are joined using a vertical-direction joining bolt 27a that vertically penetrates through the connecting metal parts 28b and 29b, whereby the detachable frame portion 28 is joined to the fixed frame portion 29.

(97) Motive Power Portion

(98) The motive power portion 3 in which the traveling output apparatuses of two systems are disposed will be described next.

(99) The region that exists below the seat support frame 24 and the region that exists above the motive power portion support frame 30 correspond to the motive power portion 3.

(100) In the traveling output apparatuses of two systems, the traveling output apparatus of one system is the engine 6, which is constituted by an internal combustion engine, and the traveling output apparatus of another system is the electric motor 8 for travel driving.

(101) In this multi-purpose work vehicle, a configuration is used in which the rear wheels 4R are driven by the power of the engine 6, and the front wheels 4F are driven by the driving power of the electric motor 8.

(102) The state in which the driving of the rear wheels 4R by the engine 6 and the driving of the front wheels 4F by the electric motor 8 are performed at the same time is a four-wheel drive state, the driving state achieved with only the driving of the rear wheels 4R by the engine 6 is a rear two-wheel drive state, and the travel driving state achieved by only the driving of the front wheels 4F by the electric motor 8 is a front two-wheel drive state.

(103) The four-wheel drive state, the rear two-wheel drive state, and the front two-wheel drive state are switched between as appropriate using an operation of switching an operation tool (not shown) in the driving portion 2, although a specific description of this will not be included.

(104) As shown in FIGS. 2 to 4, in the motive power portion 3, in a region existing above the motive power portion support frame 30, the engine 6, which is in a laterally-placed orientation in which the output shaft (not shown) is aligned with the left-right direction of the vehicle body, is provided in a rearwardly-inclined orientation in which a cylinder head 6A side of the engine 6 is located further toward the rear of the vehicle body than the output shaft. By including the engine 6 in a rearwardly-inclined orientation in this manner, the overall height of the engine 6 can be made lower while the output shaft is maintained in a horizontal orientation, and the overall height of the motive power portion 3 can be made lower.

(105) The transmission case 7 in which the transmission is included is disposed rearward of the engine 6. A belt-type continuously variable speed change apparatus 31 is disposed toward the left lateral side of the engine 6 and the transmission case 7, and an exhaust processing apparatus 33 such as a muffler is disposed at an intermediate position of an exhaust pipe 32, which extends rearward along the upper side of the belt-type continuously variable speed change apparatus 31.

(106) As shown in FIGS. 6 to 8, in a region that exists below the seat support frame 24 in the motive power portion 3, the fuel tank 34 for supplying fuel to the engine 6 is provided at a right-side end portion of the below-seat space s2 as described above, and various electric devices 37 for control, which transmit control signals to the engine 6 and the electric motor 8, are provided at the left-side end portion of the below-seat space s2.

(107) Also, a control battery 36 for outputting control signals to the various electric devices 37 for control or for supplying power for controlling the operation of the engine 6 is disposed at the left-side end portion of the below-seat space s2 in a state in which only the front-side portion of the control battery 36 exists below the seat support frame 24, and the rearward-side portion of the control battery 36 extends rearward past the lower side of the seat support frame 24 (see FIG. 10).

(108) In the region existing below the seat support frame 24, the electric motor 8 for driving the front wheels 4F and the battery 9 for supplying power to the electric motor 8 are disposed between the left and right main frames 10, which corresponds to the center in the left-right direction.

(109) The battery 9 is a lithium ion battery, and is constituted by a plug-in type that takes in power from outside.

(110) The battery 9 is disposed in a state of being slightly lifted up by the right attachment platform 35R and the left attachment platform 35L in the below-seat space s2, the electric motor 8 being located below the battery 9. The battery 9 is disposed in a state of being located in front of the engine 6, being slightly lifted up by the right attachment platform 35R and the left attachment platform 35L, and being located within range of a height that is about the same as that of the engine 6.

(111) The output shaft (not shown) of the electric motor 8 protrudes toward the vehicle body frontward side. A front wheel drive shaft 15 is joined to the output shaft and the power of the electric motor 8 is transmitted to the front wheels 4F via a front wheel differential case 16 and the front axles 17.

Other Embodiment 1

(112) In the above-described embodiment, it was described that a gasoline engine is included as the engine 6, but there is no limitation to this structure.

(113) For example, it is possible to use a diesel specification that includes a diesel engine.

(114) As for the other configurations, it is sufficient to employ configurations similar to those in the above-described embodiment.

Other Embodiment 2

(115) In the above-described embodiment, an example was given in which a plug-in type of battery 9 is used, but there is no limitation to this structure.

(116) For example, it is possible to enable charging of the battery 9 using a generator or a regeneration device driven by the engine 6.

(117) As for the other configurations, it is sufficient to employ configurations similar to those in the above-described embodiment.

Other Embodiment 3

(118) In the above-described embodiment, a structure in which the electric motor 8 is equipped in the below-seat space s2 was described as an example, but there is no limitation to this structure.

(119) For example, it is possible to equip the electric motor 8 in the space above the engine-side frame portion 40 and omit the motor-side frame portion 50.

(120) As for the other configurations, it is sufficient to employ configurations similar to those in the above-described embodiment.

Other Embodiment 4

(121) In the above-described embodiment, a structure in which the electric motor 8 is placed below the battery 9 was described as an example, but there is no limitation to this structure.

(122) For example, the electric motor 8 and the battery 9 may be placed side by side in the left-right direction.

(123) As for the other configurations, it is sufficient to employ configurations similar to those in the above-described embodiment.

Other Embodiment 5

(124) In the above-described embodiment, a structure in which the ROPS frame 20 is provided in the driving portion 2 was described as an example, but there is no limitation to this structure.

(125) For example, it is possible to use a structure in which a driving cabin is included instead of the ROPS frame 20, or a structure in which the ROPS frame 20 surrounding the driving portion 2 and the driving cabin are not included.

(126) As for the other configurations, it is sufficient to employ configurations similar to those in the above-described embodiment.

Other Embodiment 6

(127) In the above-described embodiment, a structure in which the battery 9 is fixed to the front portion frame 10A and the electric motor 8 is supported by the motor-side frame portion 50 was described as an example, but there is no limitation to this structure.

(128) For example, a configuration may be used in which the motor-side frame portion 50 is not used, the electric motor 8 is fixed to the front portion frame 10A along with the battery 9 and is equipped in the below-seat space s2, and the electric motor 8 can be detached from the engine 6 and the transmission case 7 mounted on the engine-side frame portion 40.

(129) As for the other configurations, it is sufficient to employ configurations similar to those in the above-described embodiment.

Other Embodiment 7

(130) The present invention can be applied to a four-wheel drive work vehicle, such as a haulage vehicle, a tractor, a riding mower, or a riding rice transplanter that includes traveling output apparatuses of two systems, namely an engine and an electric motor.

Second Embodiment

(131) An embodiment of the present invention will be described next with reference to the drawings. Note that in the description below, the direction of the arrow F shown in FIGS. 17 and 18 is a vehicle body front side, the direction of the arrow B is a vehicle body rear side, the direction of the arrow L shown in FIG. 18 is a vehicle body left side, and the direction of the arrow R is a vehicle body right side.

(132) Overall Configuration of Utility Vehicle

(133) FIGS. 17 and 18 show a utility vehicle (multi-purpose vehicle) that corresponds to a work vehicle according to the present invention. The present utility vehicle is a hybrid work vehicle that uses an engine E and an electric motor M as drive sources. The present utility vehicle includes a vehicle body frame 101, and wheel-type traveling apparatus 102 that supports the vehicle body frame 101. The traveling apparatus 102 includes a left and right pair of front wheels 102F that can be steered and can be driven, and a left and right pair of rear wheels 102B that can be driven. The traveling apparatus 102 can switch between a four-wheel drive state in which the drive power of the engine E is transmitted to the rear wheels 102B and the drive power of the electric motor M is transmitted to the front wheels 102F, a front-wheel drive state in which the drive power of the electric motor M is transmitted to the front wheels 102F and the drive power of the engine E is not transmitted to the rear wheels 102B, and a rear-wheel drive state in which the drive power of the engine E is transmitted to the rear wheels 102B and the drive power of the electric motor M is not transmitted to the front wheels 102F.

(134) A driving portion 103 on which an occupant rides is provided at a central portion in the front-rear direction of the vehicle body frame 101. A cargo bed 104 is provided at the rear portion of the vehicle body frame 101. The cargo bed 104 can dump a load rearward by swinging up and down about a rearward fulcrum. A motive power portion 105 is provided below the cargo bed 104. The motive power portion 105 includes the engine E, a belt continuously variable speed change apparatus 106 that subjects the drive power of the engine E to continuous speed change, and a transmission 107 that subjects the power resulting from the speed change performed by the belt continuously variable speed change apparatus 106 to speed change and transmits it to the traveling apparatus 102 (rear wheels 102B). The transmission 107 includes a transmission mechanism (not shown) and a differential mechanism (not shown).

(135) Driving Portion

(136) As shown in FIGS. 17 to 20, the driving portion 103 includes a driver seat 108 in which a driver sits, a passenger seat 109 in which a passenger sits, and a ROPS 110 for protecting the occupants. The driver seat 108 and the passenger seat 109 are aligned in the vehicle body left-right direction in a state in which the driver seat 108 is located on the left side and the passenger seat 109 is located on the right side. The driver seat 108 and the passenger seat 109 are supported by being installed on a seat support cover 111 (corresponds to a cover member according to the present invention). A steering wheel 112 is provided forward of the driver seat 108. The electric motor M, which drives the traveling apparatus 102 (front wheels 102F), a battery 113 that supplies power to the electric motor M, an inverter 114 for the electric motor M, and a fuel tank 115 for the engine E are disposed below the driving portion 103.

(137) Pedestal Cover

(138) A housing space S is formed inside of the seat support cover 111. The battery 113 and the inverter 114 are arranged in the housing space S. A ventilation mesh portion 111a is provided in a left wall portion of the seat support cover 111. A ventilation opening 111b is formed in a portion of the front wall portion of the seat support cover 111, the portion opposing the battery 113. The opening 111b is formed into a laterally-oblong rectangular shape so as to span over a range that is about the same as the lateral width of the battery 113 (in this embodiment, a range slightly wider than the lateral width of the battery 113). A cooling fan 116 for supplying a cooling wind to the inside of the housing space S is attached at the opening 111b.

(139) Arrangement of Battery and the Like

(140) As shown in FIGS. 19 and 20, the battery 113 is arranged forward of the engine E, at a central portion in the left-right direction in the housing space S. A recessed portion 111c that is upwardly recessed is formed above the seat support cover 111. The battery 113 enters the recessed portion 111c. The front half portion of the fuel tank 115 enters a space to the right of the battery 113 in the housing space S.

(141) The battery 113, the inverter 114, and the electric motor M are arranged in a concentrated manner so that a harness (not shown) that connects them is shorter. Specifically, the electric motor M is arranged below the battery 113, and the inverter 114 is arranged to the left of the battery 113. A recessed portion 113a that is upwardly recessed is formed on the lower surface portion of the battery 113. The electric motor M enters the recessed portion 113a.

(142) According to this configuration, the battery 113 and the like are arranged by effectively using the housing space S inside of the seat support cover 111, and thereby space for arranging the battery 113 and the like can easily be ensured. Also, the battery 113 and the like can be efficiently cooled by taking the traveling wind and the cooling wind of the cooling fan 116 into the housing space S through the opening 111b.

(143) Drive Control of the Cooling Fan

(144) As shown in FIG. 21, the utility vehicle includes a vehicle speed sensor 117 that detects the vehicle speed, and a control device 118 for controlling the driving of the cooling fan 116. The control device 118 includes a traveling state determination unit 119 and a cooling fan driving unit 120. The traveling state determination unit 119 determines whether the vehicle is in a traveling state or a stopped state based on a detection value of the vehicle speed sensor 117. The cooling fan driving unit 120 drives the cooling fan 116 based on the determination result of the traveling state determination unit 119.

(145) As shown in FIG. 22, the traveling state determination unit 119 determines whether the vehicle is in the traveling state or the stopped state based on the detection value of the vehicle speed sensor 117 (S1). Then, if the vehicle is in the stopped state (S1: stopped state), the cooling fan driving unit 120 drives the cooling fan 116 (S2). Also, if the vehicle is in the traveling state (S1: traveling state), the cooling fan driving unit 120 does not drive the cooling fan 116 (S3).

(146) According to this kind of configuration, the battery 113 and the like can be efficiently cooled by driving the cooling fan 116 even in a state in which the vehicle is stopped and no traveling wind is generated. Also, if the vehicle is in the traveling state, cooling of the battery 113 and the like is achieved using the traveling wind without driving the cooling fan 116, and thus it is possible to efficiently cool the battery 113 and the like while usage of the cooling fan 116 is suppressed to save energy.

Other Embodiments

(147) (1) In the above-described embodiment, the cooling fan 116 is attached in the opening 111b, which is provided in the front wall portion of the seat support cover 111, but the present invention is not limited thereto. Instead of, or in addition to this, an opening may be provided at a location (e.g., the left wall portion, right wall portion, or the like of the seat support cover 111) other than the front wall portion of the sear support cover 111, and the cooling fan 116 may be attached at the opening. For example, the cooling fan 116 may be attached to a mesh portion 111a provided in the left wall portion of the seat support cover 111.

(148) (2) The shape of the opening 111b is not limited to being the shape according to the above-described embodiment. Also, the number of cooling fans 116 is not limited to being one, and multiple cooling fans 116 may be included.

(149) (3) As shown in FIG. 23, a heat blocking plate 121 that separates the space in which the battery 113 is housed (housing space 5) and the space in which the engine E is housed may be provided between the battery 113 and the engine E. A thermally-insulating material 122 is adhered to both the surface on the battery 113 side and the surface on the engine E side of the heat blocking plate 121. Accordingly, the hot air of the engine E is blocked by the heat blocking plate 121, whereby the influence of heat on the battery 113 can be reduced.

(150) (4) The control apparatus 118 may execute the control flow shown in FIG. 24. As shown in FIG. 24, the traveling state determination unit 119 determines whether the vehicle is in the traveling state or the stopped state based on the detection value of the vehicle speed sensor 117 (S1). Then, if the vehicle is in the stopped state (S1: stopped state), the cooling fan driving unit 120 drives the cooling fan 116 (S2). Also, if the vehicle is in the traveling state (S1: traveling state), the traveling state determination unit 119 determines whether or not the detection value of the vehicle speed sensor 117 is less than or equal to a reference value (S3).

(151) Then, if the detection value of the vehicle speed sensor 117 is less than or equal to the reference value (S3: Yes), the cooling fan driving unit 120 drives the cooling fan 116 (S2). Accordingly, even if the traveling wind decreases due to a drop in the vehicle speed, the battery 113 and the like can be efficiently cooled by driving the cooling fan 116. Also, if the detection value of the vehicle speed sensor 117 exceeds the reference value (S3: No), the cooling fan driving unit 120 does not drive the cooling fan 116 (S4).

(152) In the other embodiment (4), the cooling fan driving unit 120 may drive the cooling fan 116 at a constant rotation rate in a region in which the detection value of the vehicle speed sensor 117 is less than or equal to the reference value. Alternatively, in the region in which the detection value of the vehicle speed sensor 117 is less than or equal to the reference value, the cooling fan driving unit 120 may drive the cooling fan 116 at a higher rotation rate the lower the detection value of the vehicle speed sensor 117 is. Accordingly, since the cooling wind of the cooling fan 116 increases the more the vehicle speed decreases, the efficiency of cooling the battery 113 and the like can be further improved.

(153) (5) In the above-described embodiment, the work vehicle according to the invention is a hybrid work vehicle that uses the engine E and the electric motor M as drive sources, but it is possible to use an electric work vehicle that uses only the electric motor M as the drive source.

(154) (6) The present invention can be used in a tractor, a rice transplanter, or a combine instead of in a utility vehicle. Also, the present invention can be used in a construction work vehicle instead of in an agricultural work vehicle.