Electric tractor

Abstract

This electric tractor comprises: a driving section 8 having a floor 38 at the lower portion thereof; a battery 10 provided forward of the driving section 8; a front axle case 7 to which right and left front wheels 1 are attached and which is provided below the battery 10; electric motors 11, 12 which are provided rearward of the rear end of the battery 10 and below the floor 38, and to which electric power of the battery 10 is supplied; and a transmission case 6 to which a rear traveling device 2 is attached, which is provided rearward of the electric motors 11, 12, and inside of which is provided a transmission mechanism to which power of the electric motors 11, 12 is transmitted.

Description

electric tractor

[0001] The present invention relates to the overall configuration of an electric tractor.

[0002] As disclosed in Patent Document 1, some tractors are provided with an engine as a power source. In Patent Document 1, a driver's section in which an operator sits is provided on a body provided with front and rear wheels. The engine is provided in front of the driver's section, a front axle case to which the front wheels are attached is provided below the engine, and a transmission case to which the rear wheels are attached is provided below the driver's section. A transmission shaft is connected between the engine and the transmission case, and a front wheel transmission shaft is connected between the transmission case and the front axle case.

[0003] In Patent Document 1, engine power is transmitted via a transmission shaft to a travel transmission inside a transmission case, and then from the transmission to the rear wheels. Power branched from the transmission is transmitted to the front wheels via a front wheel transmission shaft. Inside the transmission case, the engine power is branched and transmitted to a PTO shaft, and the power of the PTO shaft is transmitted to a work implement equipped on the tractor. A hydraulic pump is driven by the engine power, and hydraulic oil from the hydraulic pump is supplied to hydraulic equipment provided on the tractor and to hydraulically operated work implements equipped on the tractor.

[0004] Japanese Patent Application Publication No. 2011-88523

[0005] In the field of tractors, electric tractors have been proposed that are equipped with an electric motor that generates power for traveling, an electric motor that generates power and hydraulic pressure to operate the equipped working implements, and a battery that supplies power to the electric motor. The object of the present invention is to configure an electric tractor so that a preferable weight balance can be obtained.

[0006] The electric tractor of the present invention comprises a driving section having a floor underneath, a battery located forward of the driving section, a front axle case to which right and left front wheels are attached and located below the battery, an electric motor located rearward of the rear end of the battery and below the floor and to which power from the battery is supplied, and a transmission case located rearward of the electric motor, to which a rear running device is attached and which has a transmission mechanism inside to transmit the power of the electric motor.

[0007] According to the present invention, the battery is provided forward of the driver's section and the front axle case is provided below the battery. The electric motor is provided below the floor of the driver's section and rearward of the battery. The transmission case to which the rear traveling device is attached is provided rearward of the electric motor.

[0008] According to the present invention, the battery, electric motor, and transmission case, which are heavy objects, are arranged in that order from the front to the rear of the electric tractor. The electric motor, which is a heavy object, is arranged in a low position below the floor of the driver's section, and is arranged in a position close to the center of the front and rear of the electric tractor. This allows for a low center of gravity of the electric tractor, achieving a favorable weight balance for the electric tractor and improving the driving performance of the electric tractor.

[0009] In the present invention, it is preferable that the electric motor generates power for traveling.

[0010] According to the present invention, a preferable weight balance can be obtained in an electric tractor provided with an electric motor that generates power for traveling, which is advantageous in terms of improving the traveling performance of the electric tractor.

[0011] In the present invention, it is preferable that the electric motor generates power and hydraulic pressure for operating an attached working device.

[0012] According to the present invention, a preferable weight balance can be achieved in an electric tractor provided with an electric motor that generates power and hydraulic pressure to operate the equipped working implement, which is advantageous in terms of improving the driving performance of the electric tractor.

[0013] In the present invention, it is preferable that the vehicle be provided with a first electric motor that generates power for traveling, and a second electric motor that generates power and hydraulic pressure for operating an attached working device.

[0014] According to the present invention, the electric tractor is driven by the power of the first electric motor, and the working device is operated by the power of the second electric motor. By separately providing the first electric motor for driving and the second electric motor for operating the working device, the working device can be operated with less influence from fluctuations in load during driving, and the electric tractor can be driven with less influence from fluctuations in load on the working device.

[0015] According to the present invention, in an electric tractor provided with a first electric motor that generates power for traveling and a second electric motor that generates power and hydraulic pressure to operate an equipped working device, a favorable weight balance is achieved, which is advantageous in terms of improving the traveling performance of the electric tractor.

[0016] In the present invention, it is preferable that the first electric motor and the second electric motor are arranged side by side in the left-right direction.

[0017] According to the present invention, the first electric motor and the second electric motor are arranged side by side in the left-right direction, so that the first electric motor and the second electric motor are arranged at approximately the same position in the front-to-back direction and at approximately the same height in the up-to-down direction, thereby achieving a favorable weight balance in the electric tractor, which is advantageous in terms of improving the driving performance of the electric tractor.

[0018] In the present invention, it is preferable that the vehicle is provided with a housing frame that houses the electric motor and a front frame to which the front axle case is attached, the front frame being connected to the front part of the housing frame, and the transmission case being connected to the rear part of the housing frame.

[0019] According to the present invention, a storage frame that houses an electric motor and a front frame to which a front axle case (front wheels) is attached are provided. The front frame (front wheels and front axle case) is connected to the front part of the storage frame, and the transmission case (rear traveling device) is connected to the rear part of the storage frame. In this way, by connecting the front frame, storage frame, and transmission case to each other, the front wheels and rear traveling device can be supported with sufficient rigidity.

[0020] In the present invention, it is preferable that the front axle case is attached to a lower part of the front frame, and the battery is attached to an upper part of the front frame.

[0021] According to the present invention, by attaching the front axle case to the lower part of the front frame and the battery to the upper part of the front frame, a configuration in which the battery is located forward of the driving section can be easily obtained, and a configuration in which the front axle case is located below the battery can be easily obtained.

[0022] In the present invention, a first electric motor and a second electric motor are provided, the first electric motor and the second electric motor are arranged side by side along the left-right direction and housed in the housing frame, and it is preferable that the left-right width of the housing frame is larger than the left-right width of the front frame and larger than the left-right width of the transmission case.

[0023] According to the present invention, when a first electric motor and a second electric motor are provided, the first electric motor and the second electric motor are accommodated in the accommodation frame in a line along the left-right direction, thereby reducing the length of the accommodation frame (first electric motor and second electric motor) in the front-to-rear direction.

[0024] When the first electric motor and the second electric motor are arranged side by side in the left-right direction and housed in the housing frame, the length of the housing frame in the front-rear direction is reduced, but the width of the housing frame in the left-right direction is increased.

[0025] According to the present invention, the left-right width of the storage frame is greater than the left-right width of the front frame and greater than the left-right width of the transmission case. By connecting the front frame, storage frame, and transmission case in this order, the storage frame can be comfortably installed between the front wheels and rear traveling devices in a side view without interfering with them.

[0026] In the present invention, it is preferable that the width in the left-right direction of the front portion of the transmission case is smaller than the width in the left-right direction of the accommodation frame and larger than the width in the left-right direction of the rear portion of the transmission case.

[0027] According to the present invention, when the front portion of the transmission case is connected to the rear portion of the accommodation frame, the left-right width of the front portion of the transmission case is greater than the left-right width of the rear portion of the transmission case. This reduces the left-right width of the accommodation frame, the left-right width of the front portion of the transmission case, and the left-right width of the rear portion of the transmission case in that order, thereby improving the rigidity of the connection portion between the accommodation frame and the transmission case (the front portion of the transmission case).

[0028] 1 is a left side view of an electric tractor. FIG. 2 is a plan view of the electric tractor. FIG. 3 is a left side view of the vicinity of the front frame, storage frame and transmission case. FIG. 4 is a plan view of the vicinity of the front frame, storage frame and transmission case. FIG. 5 is a plan view of the storage frame. FIG. 6 is a bottom view of the storage frame. FIG. 7 is a front view of the storage frame. FIG. 8 is a rear view of the storage frame. FIG. 9 is an exploded perspective view of the storage frame. FIG. 10 is a left side view showing a linking mechanism between the brake pedal and the brake. FIG. 11 is a rear view of the vicinity of the support frame to which the operation handle etc. are attached. FIG. 12 is a plan view showing a linking mechanism between the brake pedal and the brake. FIG. 13 is a longitudinal front view showing a linking mechanism between the brake pedal and the brake. FIG. 14 is a left side view of an electric tractor equipped with a front loader device. FIG. 15 is a plan view of the vicinity of the front frame, storage frame and transmission case when the front loader device is equipped. FIG. 16 is a left side view of an electric tractor equipped with a front loader device and a backhoe device. FIG. 17 is a plan view of the vicinity of the front frame, storage frame and transmission case when the front loader device and a backhoe device are equipped.

[0029] Figures 1 to 17 show an electric tractor, and in Figures 1 to 17, F indicates the forward direction, B indicates the rearward direction, U indicates the upward direction, D indicates the downward direction, R indicates the rightward direction, and L indicates the leftward direction.

[0030] 1 and 2, right and left front wheels 1 are provided at the front of a machine body 3, and right and left rear wheels 2 are provided at the rear of the machine body 3, and the machine body 3 is supported by the front wheels 1 and the rear wheels 2. In this case, the rear wheels 2 serve as the rear traveling device.

[0031] The machine body 3 has a front frame 4, a storage frame 5, and a transmission case 6. The machine body 3 is constructed by connecting the front frame 4 to a front portion 14 (see FIGS. 5 to 9) of the storage frame 5, and connecting the transmission case 6 to a rear portion 15 (see FIGS. 5 to 9) of the storage frame 5. A first electric motor 11 and a second electric motor 12, which serve as power sources, are housed in the storage frame 5. In this case, the front frame 4 serves as a first front frame.

[0032] A front axle case 7 is attached to the front frame 4, and right and left front wheels 1 are attached to the front axle case 7. Right and left rear wheels 2 are attached to a transmission case 6.

[0033] A driver's section 8, in which an operator sits, is provided across the housing frame 5 and the transmission case 6. A ROP frame 9 is attached to the transmission case 6, extends upward, and is provided behind the driver's section 8. A battery 10 that supplies power to electric motors 11, 12 is attached to the front frame 4, and a hood 13 is provided to cover the battery 10.

[0034] 5 to 9, the storage frame 5 has a front portion 14, a rear portion 15, a right lateral portion 16, a left lateral portion 16, frames 17, 19, 20, 21, etc. In this case, the right and left lateral portions 16 of the storage frame 5 correspond to the right and left portions of the storage frame 5.

[0035] The front section 14 and the rear section 15 are configured as flat plates extending in the up-down and left-right directions. The right and left lateral sections 16 are configured as flat plates extending in the up-down and front-rear directions, but are slightly curved. The front sections of the lateral sections 16 are connected to the right and left sections of the rear surface of the front section 14, and the rear sections of the lateral sections 16 are connected to the right and left sections of the front surface of the rear section 15.

[0036] The frame 17 is connected in the front-to-rear direction across the left-to-right center portion of the upper part of the rear surface of the front section 14 and the left-to-right center portion of the upper part of the front surface of the rear section 15. The frame 19 is connected in the left-to-right direction across the upper parts of the right and left lateral sections 16. A bracket 22 is connected across the frame 17 and the frame 19. In this case, the frame 17 serves as the upper frame of the storage frame 5.

[0037] The right and left frames 20 are connected to the lower portions of the right and left lateral portions 16 in the front-to-rear direction. A frame 21 is connected across the right and left frames 20 in the left-to-right direction. A recess 14a that is open downward and faces upward is provided in the left-to-right center of the lower portion of the front portion 14. An opening 15a is formed in the left-to-right center of the rear portion 15. In this case, the frame 21 serves as the lower frame of the storage frame 5.

[0038] 5 to 8, the electric motors 11, 12 are arranged side by side in the left-right direction inside the storage frame 5 (between the front portion 14 and the rear portion 15, between the right and left lateral portions 16, and between the frames 17, 19 and the frame 21). The electric motors 11, 12 are identical and have the same output.

[0039] A flange portion 11a at the rear end of the electric motor 11 is connected to the left portion of the front surface of the rear portion 15 of the storage frame 5. A flange portion 12a at the rear end of the electric motor 12 is connected to the right portion of the front surface of the rear portion 15 of the storage frame 5. Output shafts 11b, 12b of the electric motors 11, 12 are provided at the positions of the flange portions 11a, 12a of the electric motors 11, 12, extending rearward along the front-to-rear direction.

[0040] Inside the storage frame 5, the electric motor 11 is provided on the left side of the recess 14a in the front part 14 and the opening 15a in the rear part 15 of the storage frame 5. The electric motor 12 is provided on the right side of the recess 14a in the front part 14 and the opening 15a in the rear part 15 of the storage frame 5.

[0041] 3, a flat cover 25 is attached across the lower portions of the right and left lateral portions 16, which are the bottom of the storage frame 5, and across the lower portions of the front portion 14 and rear portion 15 of the storage frame 5. In this case, the cover 25 serves as an electric motor protection member.

[0042] (Configuration of mounting portion and inverter for mounting working device) As shown in Figures 5 to 9, on the right and left horizontal portions 16 of the storage frame 5, upper mounting portions 16a are provided on the upper front portion of the horizontal portion 16, facing diagonally upward, and lower mounting portions 16a are provided on the lower front portion of the horizontal portion 16, facing diagonally downward.

[0043] The right mounting portion 23 is connected across the mounting portion 16 a of the right horizontal portion 16 of the storage frame 5. The left mounting portion 23 is connected across the mounting portion 16 a of the left horizontal portion 16 of the storage frame 5. As will be described later, a working device such as a front loader device 65 (see FIG. 14 ) is attached to the right and left mounting portions 23.

[0044] 1 to 4, the right and left inverters 24 are attached to the right and left lateral portions 16 of the storage frame 5, and are provided rearward of the mounting portion 23. As will be described later, a speed change pedal 35 is provided on the driving portion 8.

[0045] Power from the battery 10 is supplied to the left inverter 24, and based on the operation of the speed change pedal 35, the DC power from the battery 10 is converted to AC power in the left inverter 24 and supplied to the electric motor 11, causing the electric motor 11 to operate in the forward direction (to move the electric tractor forward) and in the reverse direction (to move the electric tractor backward).

[0046] The power of the battery 10 is supplied to the right inverter 24, which converts the DC power of the battery 10 into AC power and supplies it to the electric motor 12, thereby operating the electric motor 12. The electric motor 12 drives a hydraulic pump (not shown) as will be described later, and therefore operates in the forward direction and does not operate in the reverse direction.

[0047] (Configuration of front frame and front axle case) As shown in Figures 1, 3 and 4, right and left front frames 4 are provided, and the front frames 4 are connected to the upper part of the front surface of the front part 14 of the storage frame 5 (see Figures 5 to 9) and extend forward.

[0048] There are provided right and left front frames 26. At the lower portion of the front surface of the front portion 14 (see FIGS. 5 to 9) of the storage frame 5, the rear portion of the front frame 26 is connected to the lower portion of the front frame 4, and the front portion of the front frame 26 is connected to the front-to-rear intermediate portion of the front frame 4. In this case, the front frame 26 serves as a second front frame.

[0049] A battery 10 is attached to the upper part of the front frame 4, and the rear end of the battery 10 is located forward of the front ends of the electric motors 11, 12. A front axle case 7 (front wheels 1) is attached to the lower front part of the front frame 4 in a rollable manner, and is located below the battery 10 and forward of the electric motors 11, 12.

[0050] A flat cover 27 is attached across the right and left front frames 26. In a side view, the front frames 26 and the cover 27 are tilted upward in a front-upward position, with the front portions of the front frame 26 and the cover 27 higher than the rear portions of the front frame 26 and the cover 27. In this case, the cover 27 serves as a front wheel drive shaft protection member.

[0051] 4, the right and left front frames 4, 26 and the cover 27 have the same width W2 in the left-right direction. The width W1 in the left-right direction of the storage frame 5 is larger than the width W2 in the left-right direction of the right and left front frames 4, 26 and the cover 27.

[0052] In a plan view, the output shaft 11b of the electric motor 11 is located at the position of an imaginary line L1 extending rearward from the left front frame 4, 26. The output shaft 12b of the electric motor 12 is located at the position of an imaginary line L2 extending rearward from the right front frame 4, 26. As a result, the width W2 in the left-right direction between the right and left front frames 4, 26 and the cover 27 is approximately the same as the width (spacing) in the left-right direction between the output shafts 11b, 12b of the electric motors 11, 12.

[0053] 3 and 4, the transmission case 6 has a front portion 6a, a rear portion 6b, and right and left rear axle cases 6c, and the right and left rear wheels 2 are attached to the rear axle cases 6c of the transmission case 6. The front portion 6a of the transmission case 6 is connected to the rear surface of the rear portion 15 of the housing frame 5, and the transmission case 6 is provided rearward of the electric motors 11, 12.

[0054] The left-right width W1 of the housing frame 5 is greater than the left-right widths W3 and W4 of the front portion 6a of the transmission case 6. The left-right widths W3 and W4 of the front portion 6a of the transmission case 6 are greater than the left-right width W5 of the rear portion 6b of the transmission case 6.

[0055] A hydraulic multi-plate traveling clutch (not shown), an auxiliary transmission (not shown), and a rear wheel differential (not shown) are provided inside the transmission case 6. The auxiliary transmission is configured as a gear-shift type and is capable of changing speeds between high and low speeds. Power from the output shaft 11b of the electric motor 11 is transmitted to the traveling clutch, from the traveling clutch to the auxiliary transmission, and from the auxiliary transmission to the rear wheels 2 via the rear wheel differential. In this case, the hydraulic multi-plate traveling clutch, the auxiliary transmission, and the rear wheel differential form a transmission mechanism.

[0056] Inside the transmission case 6, the power branched off between the sub-transmission device and the rear wheel differential device is transmitted to the front wheel transmission shaft 31 described later, from the front wheel transmission shaft 31 to the front wheel differential device (not shown) inside the front axle case 7, and from the front wheel differential device to the front wheels 1.

[0057] A PTO shaft 28 is provided facing rearward in the rear portion 6b of the transmission case 6, and a mid-PTO shaft 29 is provided facing forward in the bottom of the rear portion 6b of the transmission case 6. A hydraulic multi-plate PTO clutch (not shown) and a PTO transmission system (not shown) are provided inside the transmission case 6. Power from the output shaft 12b of the electric motor 12 is transmitted to the PTO clutch, from the PTO clutch to the PTO transmission system, and from the PTO transmission system to the PTO shaft 28 and mid-PTO shaft 29. In this case, the PTO clutch and PTO transmission system form a transmission mechanism.

[0058] In the electric tractor, when a work implement such as a rotary tiller (not shown) is attached to the rear of the machine body 3, the power of the PTO shaft 28 is transmitted to the work implement. When a work implement such as a mower (not shown) is attached to the lower part of the machine body 3 between the front wheels 1 and the rear wheels 2, the power of the mid-PTO shaft 29 is transmitted to the work implement.

[0059] 3 and 4 , a pipe member 30 is connected in the front-to-rear direction between the rear portion 15 of the accommodating frame 5 and the front axle case 7. The front wheel transmission shaft 31 described above is provided inside the pipe member 30 and is connected between the inside of the transmission case 6 and the front wheel differential device of the front axle case 7.

[0060] As shown in Figures 7, 8, and 9, in the storage frame 5, the pipe member 30 and the front wheel transmission shaft 31 are provided in a recess 14a in the front part 14 of the storage frame 5, and the front wheel transmission shaft 31 is provided in an opening 15a in the rear part 15 of the storage frame 5.

[0061] A bearing portion 32 is provided in the opening 15a of the rear portion 15 of the storage frame 5. The front wheel transmission shaft 31 is supported by the bearing portion 32 and is supported by the rear portion 15 of the storage frame 5 via the bearing portion 32. The rear end portion of the pipe member 30 is attached to the bearing portion 32.

[0062] 3, 4, 7, and 8, the pipe member 30 and the front wheel transmission shaft 31 are disposed between the right and left front frames 4, 26 in a plan view, and are disposed above the cover 27. The pipe member 30 and the front wheel transmission shaft 31 are disposed between the output shaft 11b of the electric motor 11 and the output shaft 12b of the electric motor 12 in a plan view, and are disposed in the left-right center of the storage frame 5 and directly below the frame 17 of the storage frame 5.

[0063] The pipe member 30 and the front wheel transmission shaft 31 are provided at a height that overlaps with the electric motors 11, 12 in a side view. Specifically, the pipe member 30 and the front wheel transmission shaft 31 are provided between the output shafts 11b, 12b of the electric motors 11, 12 and the lower ends of the electric motors 11, 12 in a side view, and are provided above the frame 21 of the storage frame 5.

[0064] (Configuration of Driving Section) As shown in Figures 1 and 2, the driving section 8 is provided with a steering wheel 33 for steering the front wheels 1, a driver's seat 34, the aforementioned speed change pedal 35, right and left brake pedals 36, 37, a floor 38, etc.

[0065] As shown in Figures 12 and 13, right and left support parts 39 made of elastically deformable rubber are provided on the right and left parts of the frame 19 of the storage frame 5, and the support parts 39 are provided between a floor 38 provided below the driving unit 8 and the storage frame 5 (frame 19).

[0066] As shown in Figures 3 and 4, right and left support parts 40 made of elastically deformable rubber are provided on the right and left parts of the rear part 6b of the transmission case 6, and the support parts 40 are provided between the rear of the driver's section 8 and the rear part 6b of the transmission case 6.

[0067] 3, 4, 12, and 13, a floor 38 is attached to a support portion 39, which is attached to and supported by the housing frame 5 via the support portion 39, and the speed change pedal 35 is provided on the right side of the floor 38. The rear portion of the driver's section 8 is attached to a support portion 40, which is attached to and supported by the rear portion 6b of the transmission case 6 via the support portion 40.

[0068] 1 and 2 , a footstep 41 is attached to the left side of the floor 38, and an operator mainly gets on and off the driver's section 8 from the left side of the machine body 3. The storage frame 5 and the electric motors 11, 12 are provided below the floor 38. The battery 10 is provided forward of the driver's section 8 so that the rear end of the battery 10 is located forward of the front ends of the electric motors 11, 12.

[0069] 10 and 11, the support frame 42 is attached to the floor 38 and extends upward from the floor 38. The support frame 42 has a partition wall portion 42a, a pillar portion 42b, and support plates 42c and 42d.

[0070] In the support frame 42, the partition wall portion 42a is formed in a flat plate shape and attached to the front part of the floor 38, separating the inside of the hood 13, the battery 10, and the driver's section 8. The pillar portion 42b is formed in an arch shape when viewed from the front, and is connected to the outer periphery of the partition wall portion 42a.

[0071] In the support frame 42, the support plate 42c is formed in a vertically long flat plate shape and is connected to the left-right central portion of the lower part of the partition wall portion 42a. The support plate 42d is formed in a flat plate shape and is connected to the left-right central portion of the partition wall portion 42a and extends rearward.

[0072] (Configuration of the steering handle, power steering device, and display unit on the support frame) As shown in Figure 11, the base of the steering handle 33 is attached to the upper part of the support plate 42c and the support plate 42d of the support frame 42, and the steering handle 33 is attached to the support frame 42.

[0073] A fully hydraulic power steering device 43 is attached to the lower part of the support plate 42c of the support frame 42, and the power steering device 43 is attached to a portion of the support frame 42 below the steering handle 33. A steering shaft 33a extending downward from the base of the steering handle 33 is connected to the power steering device 43.

[0074] As shown in FIGS. 2, 3 and 4, a steering cylinder 44 is attached to the front axle case 7, and hydraulic oil is supplied to the steering cylinder 44 from the power steering device 43.

[0075] When the steering handle 33 is operated, the power steering device 43 is operated by the steering shaft 33a of the steering handle 33, hydraulic oil is supplied from the power steering device 43 to the steering cylinder 44, and the steering cylinder 44 is activated to steer the front wheels 1.

[0076] 2 and 11, the display unit 45 is attached to the upper portion of the support plates 42c and 42d of the support frame 42. The display unit 45 is configured with a liquid crystal panel, and various information is displayed on the display unit 45.

[0077] (Configuration of Pillar Frames and Bonnet) As shown in Figures 10 and 12, pillar frames 18 are provided that are configured in an arch shape when viewed from the front, and the pillar frames 18 are provided adjacent to the front side of the support frame 42.

[0078] 5, 9, and 12, right and left brackets 16b are provided on the front portions of the upper parts of the right and left horizontal portions 16 of the storage frame 5. The right and left lower portions of the pillar frames 18 are connected to the right and left brackets 16b of the storage frame 5 (horizontal portions 16), and the pillar frames 18 extend upward from the storage frame 5.

[0079] In this case, no support parts 39, 40 are provided between the lower part of the pillar frame 18 and the bracket 16b of the storage frame 5 (horizontal part 16), and the lower part of the pillar frame 18 is directly connected to the bracket 16b of the storage frame 5 (horizontal part 16).

[0080] 1 and 2, the hood 13 is attached to the upper part of the pillar frame 18 so as to be swingable about an axis extending in the left-right direction. The hood 13 can be opened and closed between a closed position (see FIG. 1) and an open position above the closed position.

[0081] 10 to 13, a pipe member 46 is connected along the left-right direction to an upper portion of the support plate 42d of the support frame 42. A fulcrum shaft 47 is attached to the pipe member 46 so as to be rotatable about an axis P1 that extends along the left-right direction, and a left portion of the fulcrum shaft 47 is rotatably supported by a bracket 42e connected to the partition wall portion 42a of the support frame 42.

[0082] A boss portion 36a is connected to the upper portion of the right brake pedal 36, and the boss portion 36a of the right brake pedal 36 is connected to the left portion of the fulcrum shaft 47, and the right brake pedal 36 extends downward from the fulcrum shaft 47. The right brake pedal 36 and the fulcrum shaft 47 swing integrally around the axis P1.

[0083] A boss portion 37a is connected to the upper portion of the left brake pedal 37, and the boss portion 37a of the left brake pedal 37 is rotatably attached to the left portion of the fulcrum shaft 47, and the left brake pedal 37 extends downward from the fulcrum shaft 47. The left brake pedal 37 swings about the axis P1 independently of the right brake pedal 36 and the fulcrum shaft 47.

[0084] An operator seated in the driver's seat 34 depresses the right and left brake pedals 36, 37 forward with their left foot from the position shown in Figure 10. Return springs 48 are attached to the boss portions 36a, 37a of the right and left brake pedals 36, 37. When the operator releases their left foot from the right and left brake pedals 36, 37, the return springs 48 return the right and left brake pedals 36, 37 to the position shown in Figure 10.

[0085] 10, 11, and 12, a right brake 50 capable of braking the right rear wheel 2 and a right brake 51 capable of braking the left rear wheel 2 are provided on the rear portion 6b of the transmission case 6. A right linking mechanism 52 is connected between the right brake pedal 36 and the right brake 50 as described below. A left linking mechanism 53 is connected between the left brake pedal 37 and the left brake 51 as described below.

[0086] The right linking mechanism 52 has a right linking rod 54, a pipe member 56, a right linking rod 57, a pipe member 59, a right crank member 60, a right linking rod 61, and a right linking rod 62. In this case, the pipe member 59 is the left and right part, the linking rod 61 is the top and bottom part, and the linking rod 62 is the front and back part.

[0087] The left linking mechanism 53 has a left linking rod 54, a linking shaft 55, a left linking rod 57, a linking shaft 58, a left crank member 60, a left linking rod 61, and a left linking rod 62. In this case, the linking shaft 58 is the left-right part, the linking rod 61 is the upper and lower part, and the linking rod 62 is the front-rear part.

[0088] The bracket 49 is connected to the frame 19 of the storage frame 5, and two pipe members 63 are connected to the brackets 22, 49 of the storage frame 5 at a distance in the left-right direction. A linking shaft 55 is attached to the pipe member 63 so as to be rotatable about an axis P2 extending in the left-right direction. An arm 55a is connected to the left end of the linking shaft 55, and an arm 55b is connected to the left-right center of the linking shaft 55 (the portion between the two pipe members 63).

[0089] A pipe member 56 is attached to the right portion of the linking shaft 55 so as to be rotatable about the axis P2 independently of the linking shaft 55. An arm 56a is connected to the right end of the pipe member 56, and an arm 56b is connected to the left end of the pipe member 56.

[0090] The right linking rod 54 is connected between the arm 47a of the fulcrum shaft 47 and the arm 56a of the pipe member 56. The left linking rod 54 is connected between the arm 37b of the left brake pedal 37 and the arm 55a of the linking shaft 55.

[0091] (Configuration of linkage mechanism connecting brake pedal and brake)-2 As shown in Figures 10 to 13, two pipe members 64 are connected to the upper side of the rear part 6b of the transmission case 6 with a gap between them in the left-right direction. A linkage shaft 58 is attached to the pipe members 64 so as to be rotatable about an axis P3 that runs along the left-right direction. An arm 58a is connected to the left end of the linkage shaft 58, and an arm 58b is connected to the left-right center of the linkage shaft 58 (the part between the two pipe members 64).

[0092] A pipe member 59 is attached to the right portion of the linking shaft 58 so as to be rotatable about the axis P3 independently of the linking shaft 58. An arm 59a is connected to the right end of the pipe member 59, and an arm 59b is connected to the left end of the pipe member 59.

[0093] The right linking rod 57 is connected across the arm 56b of the pipe member 56 and the arm 59b of the pipe member 59. The left linking rod 57 is connected across the arm 55b of the linking shaft 55 and the arm 58b of the linking shaft 58.

[0094] In the floor 38 of the driving section 8, a raised portion 38a is formed in the central left and right part of the floor 38, which is curved so as to rise upward more than other parts of the floor 38, and the raised portion 38a is provided along the front-to-rear direction from the front end to the rear end of the floor 38.

[0095] The right and left linking rods 57 are arranged side by side in the left-right direction and in the front-rear direction between the raised portion 38a of the floor 38 and the housing frame 5. The right and left linking rods 57 extend to a position (linking shaft 58 and pipe member 59) above the rear portion 5b of the transmission case 6.

[0096] 10 and 12, the right portion of the linkage shaft 58 and the pipe member 59 extend laterally outward to the right from the center of the rear portion 6b of the transmission case 6, and extend to above the right side of the rear portion 6b of the transmission case 6. The left portion of the linkage shaft 58 extends laterally outward to the left from the center of the rear portion 6b of the transmission case 6, and extend to above the left side of the rear portion 6b of the transmission case 6.

[0097] Right and left crank members 60 are attached to the right and left lateral sides of the rear portion 6b of the transmission case 6 so as to be swingable about an axis P4 along the left-right direction. A right linking rod 61 is connected between the arm 59a of the pipe member 59 and the right crank member 60. A left linking rod 61 is connected between the arm 58a of the linking shaft 58 and the left crank member 60.

[0098] The right linking rod 61 is provided along the vertical direction behind the right portion of the front part 6a of the transmission case 6 and laterally outward from the right lateral side of the rear part 6b of the transmission case 6. The left linking rod 61 is provided along the vertical direction behind the left portion of the front part 6a of the transmission case 6 and laterally outward from the left lateral side of the rear part 6b of the transmission case 6.

[0099] The right linking rod 62 is connected in the front-rear direction between the right crank member 60 and the operating portion 50a of the right brake 50. The left linking rod 62 is connected in the front-rear direction between the left crank member 60 and the operating portion 51a of the left brake 51.

[0100] (Brake operation state by brake pedal) As shown in Figures 10 to 13, when the right brake pedal 36 is depressed forward, the fulcrum shaft 47 is operated in the clockwise direction in Figure 10, the right linkage rod 54 is operated upward, and the pipe member 56 is operated in the clockwise direction in Figure 10.

[0101] When the pipe member 56 is operated clockwise in Figure 10, the right linking rod 57 is operated forward, the pipe member 59 is operated counterclockwise in Figure 10, the right linking rod 61 is operated upward, the right crank member 60 is operated counterclockwise in Figure 10, the right linking rod 62 is operated rearward, the operating part 50a of the right brake 50 is operated rearward, and the right brake 50 is operated to brake.

[0102] When the left brake pedal 37 is depressed forward, the left linking rod 54 is operated upward, and the linking shaft 55 is operated clockwise in Fig. 10. When the linking shaft 55 is operated clockwise in Fig. 10, the left linking rod 57 is operated forward, the linking shaft 58 is operated counterclockwise in Fig. 10, the left linking rod 61 is operated upward, the left crank member 60 is operated counterclockwise in Fig. 10, the left linking rod 62 is operated rearward, the operating portion 51a of the left brake 51 is operated rearward, and the left brake 51 is operated to apply braking.

[0103] (Configuration of Front Loader Apparatus) As shown in Figs. 14 and 15, an electric tractor may be equipped with a front loader apparatus 65, which is a working apparatus.

[0104] The front loader device 65 has right and left bases 66 , right and left booms 67 , a bucket 68 , right and left boom cylinders 69 , and right and left bucket cylinders 70 .

[0105] Booms 67 are attached to the upper end of the base 66 so as to be able to swing up and down, and boom cylinders 69 that operate to swing the booms 67 up and down are connected between the base 66 and the booms 67. Buckets 68 are attached to the front ends of the right and left booms 67 so as to be able to swing up and down, and bucket cylinders 70 that operate to swing the buckets 68 up and down are connected between the booms 67 and the buckets 68.

[0106] 16 and 17, an electric tractor may be equipped with a front loader device 65, which is a working device, and a backhoe device 75, which is also a working device. The front loader device 65 is the same as that shown in FIGS. 14 and 15.

[0107] The backhoe device 75 has a base 76, a work seat 77, an operating lever 78, right and left outriggers 79, a swing bracket 80, a boom 81, an arm 82, a bucket 83, right and left outrigger cylinders 84, a swing cylinder 85, a boom cylinder 86, an arm cylinder 87, and a bucket cylinder 88.

[0108] An operator seat 77 and an operating lever 78 are provided on a frame-shaped base 76. Right and left outriggers 79 are attached to the base 76 so as to be able to swing up and down, and an outrigger cylinder 84 that swings the outriggers 79 up and down is connected between the base 76 and the outriggers 79.

[0109] A swing bracket 80 is attached to the base 76 so as to be swingable left and right, and a swing cylinder 85 that swings the swing bracket 80 left and right is connected between the base 76 and the swing bracket 80.

[0110] A boom 81 is attached to the swing bracket 80 so as to be able to swing up and down, and a boom cylinder 86 that swings the boom 81 up and down is connected between the swing bracket 80 and the boom 81.

[0111] An arm 82 is attached to the boom 81 so as to be swingable back and forth, and an arm cylinder 87 that swings the arm 82 back and forth is connected between the boom 81 and the arm 82. A bucket 83 is attached to the arm 82 so as to be swingable back and forth, and a bucket cylinder 88 that swings the bucket 83 back and forth is connected between the arm 82 and the bucket 83.

[0112] (Configuration when front loader device and backhoe device are mounted on electric tractor) As shown in Figures 14 to 17, when a front loader device 65 is mounted, in the front loader device 65, the lower part of the right base 66 is connected to the outer lateral surface part of the right mounting part 23 of the storage frame 5, and the lower part of the left base 66 is connected to the outer lateral surface part of the left mounting part 23 of the storage frame 5.

[0113] When only the front loader device 65 is installed, right and left front and rear frames 73 are used as shown in Figures 14 and 15. When the front loader device 65 and the backhoe device 75 are installed, right and left front and rear frames 74 are used as shown in Figures 16 and 17.

[0114] As described above, with the base 66 of the front loader device 65 connected to the mounting portion 23 of the storage frame 5, the front ends of the right front and rear frames 73, 74 are connected to the outer lateral surface of the right base 66 of the front loader device 65, and the rear ends of the right front and rear frames 73, 74 are connected to the right rear axle case 6c of the transmission case 6, as shown in FIGS. 14 to 17.

[0115] The front ends of the left front and rear frames 73, 74 are connected to the outer lateral surface of the left base 66 of the front loader device 65, and the rear ends of the left front and rear frames 73, 74 are connected to the left rear axle case 6c of the transmission case 6. In this case, the right and left rear axle cases 6c of the transmission case 6 are the portions of the transmission case 6 to which the right and left traveling devices (rear wheels 2) are attached.

[0116] The base 66 of the front loader device 65 is sandwiched between the mounting portion 23 and the front ends of the front and rear frames 73, 74, and the mounting portion 23, the front ends of the front and rear frames 73, 74 and the base 66 of the front loader device 65 are fastened together.

[0117] 16 and 17 , right and left rear mounting portions 74a are provided at the rear of the right and left front-rear frames 74. When a backhoe device 75 is installed, a base 76 of the backhoe device 75 is attached to the rear mounting portions 74a of the front-rear frames 74.

[0118] (Operational configuration of the front loader device and the backhoe device) As shown in Figures 14 to 17, a control valve unit 71 provided with a plurality of electromagnetically operated control valves is attached to the front of the right front and rear frames 73, 74. An operation lever 72 for operating the control valve unit 71 is provided on the right side of the driving section 8. In this case, the control valve unit 71 serves as the control valve.

[0119] A hydraulic pump (not shown) is driven by the electric motor 12, and hydraulic oil from the hydraulic pump is supplied to a control valve unit 71, which then supplies and discharges hydraulic oil to and from the boom cylinder 69 and bucket cylinder 70 of the front loader device 65. The hydraulic oil from the hydraulic pump is also supplied to hydraulic equipment (not shown) such as a power steering device 43 (see FIG. 11) equipped on the electric tractor, and the hydraulic equipment such as the power steering device 43 is operated by the supplied hydraulic oil.

[0120] An operator in the driver's seat 34 can operate the control valve of the control valve unit 71 by operating the operation lever 72 , thereby operating the boom 67 and bucket 68 of the front loader device 65 .

[0121] When operating the backhoe device 75, the worker switches the hydraulic pump so that hydraulic oil is supplied to the backhoe device 75. The worker sits in the work seat 77 of the backhoe device 75 and lowers the right and left outriggers 79 to touch the ground. The worker in the work seat 77 can operate the swing bracket 80, boom 81, arm 82, and bucket 83 of the backhoe device 75 by operating the operation lever 78 to operate the control valve (not shown) of the backhoe device 75.

[0122] 14 to 17, the front and rear frames 73, 74 are formed in a crank shape in plan view. The widths (spacing) W6, W8 in the left-right direction of the front portions of the right and left front and rear frames 73, 74 are greater than the widths (spacing) W7, W9 in the left-right direction of the rear portions of the right and left front and rear frames 73, 74. The widths (spacing) W7, W9 in the left-right direction of the rear portions of the right and left front and rear frames 73, 74 are approximately the same as the width W1 in the left-right direction of the storage frame 5 (see FIG. 4).

[0123] The right front and rear frames 73, 74 are provided along the front-rear direction, laterally outward to the right of the right inverter 24 and laterally outward to the right of the transmission case 6, and the control valve unit 71 is attached to the front of the right front and rear frames 73, 74. The left front and rear frames 73, 74 are provided along the front-rear direction, laterally outward to the left of the left inverter 24 and laterally outward to the left of the transmission case 6. The right and left front and rear frames 73, 74 are provided at a height that overlaps with the inverter 24, the housing frame 5, and the transmission case 6 in a side view.

[0124] The widths (intervals) W7, W9 in the left-right direction of the rear parts of the right and left front and rear frames 73, 74 are smaller than the widths (intervals) W6, W8 in the left-right direction of the front parts of the right and left front and rear frames 73, 74, so that the rear parts of the right and left front and rear frames 73, 74 do not interfere with the rear wheel 2.

[0125] (First Alternative Embodiment of the Invention) The storage frame 5 may be eliminated. According to this configuration, the electric motors 11, 12 may be attached to the lower part of the floor 38. The front frame 4 may be configured to extend rearward below the floor 38 and be connected to the transmission case 6, and the electric motors 11, 12 may be attached to a portion of the front frame 4 below the floor 38. The base 66 of the front loader device 65 may be configured to be connected to the front frame 4.

[0126] (Second alternative embodiment of the invention) Since electric motor 12 may require a larger output than electric motor 11, which generates power for traveling, electric motor 12 may be configured to have a larger output than electric motor 11.

[0127] (Third Alternative Embodiment of the Invention) The PTO shaft 28 and the mid-PTO shaft 29 may be eliminated. With this configuration, only implements that operate using hydraulic oil can be equipped on the electric tractor.

[0128] When a work implement is installed, the hydraulic oil of the hydraulic pump driven by the electric motor 12 is supplied to the work implement and hydraulic equipment such as the power steering device 43 installed on the electric tractor. When a work implement is not installed, the hydraulic oil of the hydraulic pump driven by the electric motor 12 is supplied to the hydraulic equipment such as the power steering device 43 installed on the electric tractor.

[0129] (Fourth Alternative Embodiment of the Invention) The electric motor 12 may be configured to transmit power to the PTO shaft 28 and the mid-PTO shaft 29, but not to drive the hydraulic pump.

[0130] According to this configuration, the hydraulic pump may be configured to be driven by an electric motor (not shown) separate from the electric motors 11 and 12. The hydraulic pump may be configured to be driven by the electric motor 11. In this case, the control valve unit 71 may be attached to the left front and rear frames 73 and 74.

[0131] Fifth Modification of the Invention When the electric motors 11 and 12 are arranged side by side in the left-right direction, the electric motor 11 may be arranged on the right and the electric motor 12 may be arranged on the left.

[0132] (Sixth Alternative Embodiment of the Invention) A single electric motor 11 may be housed in the housing frame 5. With this configuration, the left-right width W1 of the housing frame 5 and the left-right width W3 of the front portion 6a of the transmission case 6 may be substantially the same. In this case, the electric motor 12 may be attached to a location separate from the housing frame 5.

[0133] (Seventh Alternative Embodiment of the Invention) Two electric motors 11 may be housed side by side in the left-right direction in the housing frame 5. In this configuration, one electric motor 11 serves as the first electric motor 11, and the other electric motor 11 serves as the second electric motor 11. In this case, the electric motor 12 may be attached to a location separate from the housing frame 5.

[0134] (Eighth Alternative Embodiment of the Invention) One electric motor 12 may be housed in the housing frame 5. With this configuration, the left-right width W1 of the housing frame 5 and the left-right width W3 of the front portion 6a of the transmission case 6 may be substantially the same. In this case, the electric motor 11 may be attached to a location separate from the housing frame 5.

[0135] (Ninth Alternative Embodiment of the Invention) Two electric motors 12 may be housed side by side in the left-right direction in the housing frame 5. In this configuration, one electric motor 12 serves as the first electric motor 12, and the other electric motor 12 serves as the second electric motor 12. In this case, the electric motors 12 may be attached to a location separate from the housing frame 5.

[0136] (Tenth Alternative Embodiment of the Invention) The front portions of the electric motors 11, 12 may be connected to the front portion 14 of the storage frame 5. With this configuration, the casings of the electric motors 11, 12 become part of the storage frame 5, thereby improving the rigidity of the storage frame 5.

[0137] Eleventh Alternative Embodiment of the Invention When the front loader device 65 and the backhoe device 75 are not installed, the front and rear frames 73 and 74 may be connected across the mounting portion 23 of the storage frame 5 and the rear axle case 6 c of the transmission case 6 .

[0138] When the front loader device 65 is not installed and the front and rear frames 74 are connected between the mounting portion 23 of the storage frame 5 and the rear axle case 6c of the transmission case 6, the backhoe device 75 may be attached to the rear mounting portion 74a of the front and rear frames 74.

[0139] (Twelfth Alternative Embodiment) The vehicle may be configured as a rear two-wheel drive vehicle instead of a four-wheel drive vehicle. In this configuration, the pipe member 30, the front wheel transmission shaft 31, the bearing 32, the opening 15b in the rear portion 15 of the storage frame 5, and the recess 14a in the front portion 14 are eliminated.

[0140] Thirteenth Alternative Embodiment of the Invention Instead of the rear wheels 2, crawler-type right and left traveling devices (not shown) may be attached to the transmission case 6.

[0141] The electric tractor may not only be equipped with the electric motors 11 and 12 as a power source, but may also be configured as a hybrid type electric tractor equipped with an engine (not shown) and the electric motors 11 and 12 as a power source.

[0142] (Correspondence to Claims) -1 With the above configuration, a driving section 8 having a floor 38 underneath is provided. A battery 10 is provided in front of the driving section 8. A front axle case 7 is provided below the battery 10, to which right and left front wheels 1 are attached.

[0143] The vehicle is provided with electric motors 11, 12 that are provided behind the rear end of the battery 10 and below the floor 38 and that receive power from the battery 10. The vehicle is also provided with a transmission case 6 that is provided behind the electric motors 11, 12, to which the rear travel device (rear wheels 2) is attached, and that has a transmission mechanism installed inside to transmit the power of the electric motors 11, 12.

[0144] The electric motor 11 generates power for traveling. The electric motor 12 generates power and hydraulic pressure to operate the installed working devices (front loader device 65 and backhoe device 75). The vehicle is provided with a first electric motor 11 that generates power for traveling, and a second electric motor 12 that generates power and hydraulic pressure to operate the installed working devices (front loader device 65 and backhoe device 75).

[0145] (Correspondence to Claims) -2 With the above configuration, the first electric motor 11 and the second electric motor 12 are arranged side by side in the left-right direction. The vehicle is provided with a storage frame 5 that houses the electric motors 11, 12, and a front frame 4 to which a front axle case 7 is attached. The front frame 4 is connected to a front portion 14 of the storage frame 5, and a transmission case 6 is connected to a rear portion 15 of the storage frame 5. The front axle case 7 is attached to the lower portion of the front frame 4, and a battery 10 is attached to the upper portion of the front frame 4.

[0146] The vehicle is provided with a first electric motor 11 and a second electric motor 12, which are arranged side by side in the left-right direction and housed in the housing frame 5. The left-right width W1 of the housing frame 5 is greater than the left-right width W2 of the front frame 4, and is also greater than the left-right widths W3, W4, and W5 of the transmission case 6. The left-right widths W3 and W4 of the front portion 6a of the transmission case 6 are smaller than the left-right width W1 of the housing frame 5, and are greater than the left-right width W5 of the rear portion 6b of the transmission case 6.

[0147] The present invention can be applied to an electric tractor.

[0148] DESCRIPTION OF SYMBOLS 1 Front wheels 2 Rear wheels (rear traveling device) 4 Front frame 5 Storage frame 6 Transmission case 6a Front part of transmission case 6b Rear part of transmission case 7 Front axle case 8 Driving section 10 Battery 11 Electric motor (first electric motor) 12 Electric motor (second electric motor) 14 Front part of storage frame 15 Rear part of storage frame 38 Floor 65 Front loader device (working device) 75 Backhoe device (working device) W1 Left-right width of storage frame W2 Left-right width of front frame W3 Left-right width of transmission case (left-right width of front part of transmission case) W4 Left-right width of transmission case (left-right width of front part of transmission case) W5 Left-right width of transmission case (left-right width of rear part of transmission case)

Claims

1. An electric tractor comprising: a driver's cab having a floor at the lower part; a battery provided in front of the driver's cab; a front axle case to which right and left front wheels are attached and which is provided below the battery; an electric motor provided behind the rear end of the battery, below the floor, and supplied with power from the battery; and a transmission case provided behind the electric motor, to which a rear traveling device is attached and in which a transmission mechanism for transmitting the power of the electric motor is provided inside.

2. The electric tractor according to claim 1, wherein the electric motor generates power for traveling.

3. The electric tractor according to claim 1, wherein the electric motor generates power and hydraulic pressure for operating a mounted work implement.

4. The electric tractor according to claim 1, comprising: a first electric motor that generates power for traveling; and a second electric motor that generates power and hydraulic pressure for operating a mounted work implement.

5. The electric tractor according to claim 4, wherein the first electric motor and the second electric motor are arranged side by side along the left-right direction.

6. The electric tractor according to any one of claims 1 to 5, comprising: a housing frame that houses the electric motor; and a front frame to which the front axle case is attached, wherein the front frame is connected to the front part of the housing frame, and the transmission case is connected to the rear part of the housing frame.

7. The electric tractor according to claim 6, wherein the front axle case is attached to the lower part of the front frame, and the battery is attached to the upper part of the front frame.

8. The electric tractor according to claim 6 or 7, comprising: a first electric motor and a second electric motor, wherein the first electric motor and the second electric motor are housed in the housing frame side by side along the left-right direction, and the lateral width of the housing frame in the left-right direction is larger than the lateral width of the front frame in the left-right direction and also larger than the lateral width of the transmission case in the left-right direction.

9. The electric tractor according to any one of claims 6 to 8, wherein the lateral width of the front part of the transmission case in the left-right direction is smaller than the lateral width of the housing frame in the left-right direction and larger than the lateral width of the rear part of the transmission case in the left-right direction.

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