Electric tractor

Abstract

This electric tractor is provided with a first electric motor 11 of which an output shaft 11b is directed rearward and a second electric motor 12 of which an output shaft 12b is directed rearward. The electric tractor is also provided with a transmission case 6, which is provided rearward of the first electric motor 11 and the second electric motor 12, and to which a rear traveling device is attached. The first electric motor 11 and the second electric motor 12 are provided side by side along the lateral direction, and a front wheel transmission shaft 31 extends forward from the transmission case 6 through between the output shaft 11b of the first electric motor 11 and the output shaft 12b of the second electric motor 12 in a plan view.

Description

electric tractor

[0001] The present invention relates to a front wheel configuration, a driving system, and a power take-off (PTO) system transmission structure 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] JP 2011-88523 A

[0005] There have been proposed electric tractors equipped with an electric motor that generates power for traveling and an electric motor that generates power and hydraulic pressure to operate the attached implements. The first object of the present invention is to provide a compact front wheel drive shaft in an electric tractor. The second object of the present invention is to provide a well-balanced power transmission structure for the traveling system and PTO system in an electric tractor.

[0006] In order to achieve the first object, the electric tractor of the present invention comprises a first electric motor with an output shaft facing rearward, a second electric motor with an output shaft facing rearward, front wheels for traveling located forward of the first electric motor and the second electric motor, a transmission case located rearward of the first electric motor and the second electric motor and to which a rear traveling device is attached, a transmission mechanism located inside the transmission case and transmitting the transmitted power to the traveling device, and a front wheel transmission shaft that transmits power branched from the transmission mechanism to the front wheels, the first electric motor and the second electric motor being arranged side by side in the left-right direction, and the front wheel transmission shaft extending forward from the transmission case, passing between the output shaft of the first electric motor and the output shaft of the second electric motor in a plan view.

[0007] 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-rear direction and at approximately the same height in the up-to-down direction, thereby achieving a favorable weight balance in the electric tractor and improving the driving performance of the electric tractor.

[0008] According to the present invention, in the above-mentioned state, the front wheel drive shaft that transmits power to the front wheels extends forward from the transmission case, passing between the output shaft of the first electric motor and the output shaft of the second electric motor in a plan view. Because the front wheel drive shaft is provided through the space in which the first electric motor and the second electric motor are provided, the space in which the first electric motor and the second electric motor are provided is effectively utilized, and the front wheel drive shaft is provided compactly.

[0009] In the present invention, it is preferable that the first electric motor generates power for traveling, and the second electric motor generates power and hydraulic pressure for operating an attached working device.

[0010] 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.

[0011] In the present invention, it is preferable that the front wheel transmission shaft is provided at a height that overlaps with the first electric motor and the second electric motor in a side view.

[0012] According to the present invention, the front wheel drive shaft is arranged at a height that overlaps with the first electric motor and the second electric motor when viewed from the side, which makes effective use of the space in which the first electric motor and the second electric motor are arranged, thereby providing the advantage of allowing the front wheel drive shaft to be arranged compactly.

[0013] In the present invention, it is preferable that a storage frame is provided to store the first electric motor and the second electric motor, the front wheel transmission shaft is arranged to pass through the front and rear parts of the storage frame, and a bearing part that supports the front wheel transmission shaft is arranged at at least one of the front and rear parts of the storage frame.

[0014] According to the present invention, when a storage frame is provided to store the first electric motor and the second electric motor, the front wheel drive shaft passes through the front and rear parts of the storage frame, and the front wheel drive shaft is stably supported by the bearings provided in the front (rear) parts of the storage frame.

[0015] According to the present invention, by providing the bearing portion at the front (rear) of the storage frame, the front (rear) of the storage frame also serves as a mounting member for the bearing portion, thereby simplifying the structure.

[0016] In the present invention, it is preferable that an upper frame be provided above the front wheel drive shaft and connected in the front-to-rear direction across the front and rear of the storage frame.

[0017] According to the present invention, when the front wheel drive shaft passes through the front and rear parts of the storage frame that houses the first electric motor and the second electric motor, the upper frame is provided above the front wheel drive shaft and is connected in the front-to-rear direction across the front and rear parts of the storage frame. This reinforces the storage frame and improves its rigidity. Improved rigidity of the storage frame is advantageous in that the front wheel drive shaft is stably supported.

[0018] In the present invention, it is preferable that a lower frame be provided below the front wheel drive shaft and connected along the left-right direction across the right and left portions of the storage frame.

[0019] According to the present invention, when the front wheel drive shaft passes through the front and rear parts of the storage frame that houses the first electric motor and the second electric motor, the lower frame is provided below the front wheel drive shaft and is connected in the left-right direction across the right and left parts of the storage frame. This reinforces the storage frame and improves its rigidity. Improved rigidity of the storage frame is advantageous in that the front wheel drive shaft is stably supported.

[0020] In order to achieve the second object, the electric tractor of the present invention is provided with a first electric motor that generates power for traveling and has an output shaft facing rearward, and a second electric motor that generates power and hydraulic pressure to operate an attached working device and has an output shaft facing rearward, the first electric motor and the second electric motor are arranged side by side in the left-right direction, a transmission case is provided rearward of the first electric motor and the second electric motor and to which a rear traveling device is attached, and a first imaginary line extending rearward from the output shaft of the first electric motor and a second imaginary line extending rearward from the output shaft of the second electric motor are arranged inside the transmission case in a plan view. The electric vehicle is provided with a traveling transmission shaft that is arranged along the front-to-rear direction between the output shaft and a second imaginary line that extends rearward from the output shaft and transmits power to the traveling device, a PTO transmission shaft that is arranged along the front-to-rear direction at a position above or below the traveling transmission shaft between the first imaginary line and the second imaginary line in a plan view and transmits power to the working device, a first transmission mechanism that transmits power from the output shaft of the first electric motor toward the left-to-right center of the transmission case and transmits it to the traveling transmission shaft, and a second transmission mechanism that transmits power from the output shaft of the second electric motor toward the left-to-right center of the transmission case and transmits it to the PTO transmission shaft.

[0021] 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-rear direction and at approximately the same height in the up-to-down direction, thereby achieving a favorable weight balance in the electric tractor and improving the driving performance of the electric tractor.

[0022] According to the present invention, a transmission case to which a rear traveling device is attached is located rearward of the first electric motor and the second electric motor. A traveling transmission shaft that transmits power to the traveling device and a PTO transmission shaft that transmits power to the working device are provided inside the transmission case along the front-to-rear direction and arranged side by side along the up-down direction. When a first imaginary line is assumed to extend rearward from the output shaft of the first electric motor and a second imaginary line is assumed to extend rearward from the output shaft of the second electric motor, the traveling transmission shaft and the PTO transmission shaft are located between the first imaginary line and the second imaginary line in a plan view. This allows the left-right width of the transmission case to be reduced.

[0023] When the first electric motor and the second electric motor are arranged side by side in the left-right direction, the length of the first electric motor and the second electric motor in the front-rear direction is reduced, but the width of the first electric motor and the second electric motor in the left-right direction is increased.

[0024] According to the present invention, a transmission case having a small width in the left-right direction is provided at the rear of the first electric motor and the second electric motor, which have a large width in the left-right direction. This allows the first electric motor and the second electric motor to be comfortably provided in front of the rear traveling device in a side view without interfering with the rear traveling device.

[0025] According to the present invention, in a first electric motor and a second electric motor having a large width in the left-right direction and a transmission case having a small width in the left-right direction, the power of the output shaft of the first electric motor is transmitted by the first transmission mechanism toward the left-right center of the transmission case and then to the travel transmission shaft. The power of the output shaft of the second electric motor is transmitted by the second transmission mechanism toward the left-right center of the transmission case and then to the PTO transmission shaft. As a result, even in a first electric motor and a second electric motor having a large width in the left-right direction and a transmission case having a small width in the left-right direction, the power of the output shafts of the first electric motor and the second electric motor is transmitted smoothly to the travel transmission shaft and the PTO transmission shaft.

[0026] In the present invention, it is preferable that the left-right width of the rear part of the transmission case, which houses the traveling transmission shaft and the PTO transmission shaft, and the front part of the transmission case, which houses the first transmission mechanism and the second transmission mechanism, is smaller than the left-right width of the front part of the transmission case.

[0027] The first and second transmission mechanisms transmit power from the output shafts of the first and second electric motors toward the left-right center of the transmission case, and therefore require a space with a large left-right width to accommodate the first and second transmission mechanisms. According to the present invention, the first and second transmission mechanisms are housed in the front portion of the transmission case, which has a large left-right width, and the travel transmission shaft and PTO transmission shaft, which do not require a large left-right width, are housed in the rear portion of the transmission case, which has a small left-right width. This allows the first and second transmission mechanisms, the travel transmission shaft, and the PTO transmission shaft to be comfortably housed in the transmission case.

[0028] In the present invention, it is preferable that the inside of the transmission case is provided with a traveling relay shaft arranged in the fore-and-aft direction between the first virtual line and the second virtual line in a plan view, and a transmission device arranged across the traveling relay shaft and the traveling transmission shaft, and that the power of the output shaft of the first electric motor is transmitted from the first transmission mechanism to the traveling relay shaft, and from the traveling relay shaft to the traveling transmission shaft through the transmission device.

[0029] According to the present invention, the rotational speed of the output shaft of the first electric motor is changed to change the speed of the power transmitted to the traveling transmission shaft, thereby changing the traveling speed of the electric tractor. In this case, in order to widen the speed change range of the first electric motor, a transmission is provided inside the transmission case, and a traveling relay shaft for mounting the transmission is also provided inside the transmission case.

[0030] According to the present invention, inside the transmission case, in plan view, the traveling relay shaft is provided along the front-rear direction between the first imaginary line and the second imaginary line, and the transmission is provided across the traveling relay shaft and the traveling transmission shaft. Power from the output shaft of the first electric motor is transmitted from the first transmission mechanism to the traveling relay shaft, and from the traveling relay shaft to the traveling transmission shaft through the transmission. As a result, since the traveling relay shaft and the transmission are provided between the first imaginary line and the second imaginary line in plan view, this is advantageous in terms of reducing the width of the transmission case in the left-right direction.

[0031] In the present invention, it is preferable that the traveling relay shaft is provided between the first virtual line and the traveling transmission shaft in a plan view.

[0032] According to the present invention, the traveling intermediate shaft is provided between the first imaginary line and the second imaginary line in a plan view, between the first imaginary line and the traveling transmission shaft, and is provided at a position close to the output shaft of the first electric motor, thereby making it possible to compactly configure the first transmission mechanism that transmits power from the output shaft of the first electric motor to the traveling intermediate shaft.

[0033] In the present invention, it is preferable that a front wheel transmission shaft is provided inside the transmission case, arranged in the fore-and-aft direction between the first virtual line and the second virtual line in a plan view, at a position above or below the traveling transmission shaft, and that the power of the traveling transmission shaft is transmitted to the front wheel.

[0034] In a tractor, when the front wheels are driven in addition to the rear traveling device, a front wheel transmission shaft is provided to transmit power branched from the traveling transmission shaft to the front wheels. According to the present invention, the front wheel transmission shaft is provided inside the transmission case along the front-to-rear direction, at a position above or below the traveling transmission shaft and between the first and second imaginary lines in a plan view. The power of the traveling transmission shaft is transmitted to the front wheel transmission shaft and then to the front wheels via the front wheel transmission shaft. As a result, since the front wheel transmission shaft is provided between the first and second imaginary lines in a plan view, this is advantageous in that the width of the transmission case in the left-right direction can be made small.

[0035] In the present invention, it is preferable that the PTO transmission shaft is provided below the traveling transmission shaft, the front wheel transmission shaft is provided below the PTO transmission shaft, a traveling relay gear is provided rotatably attached to the PTO transmission shaft, and the power of the traveling transmission shaft is transmitted to the traveling relay gear and from the traveling relay gear to the front wheel transmission shaft.

[0036] In tractors, the front wheel drive shaft is often located at a relatively low position. According to the present invention, the PTO drive shaft is located below the running drive shaft, and the front wheel drive shaft is located below the PTO drive shaft, so the present invention is suitable for a configuration in which the front wheel drive shaft is located at a relatively low position.

[0037] According to the above-described configuration, the traveling transmission shaft and the front wheel transmission shaft may be separated in the vertical direction. According to the present invention, the traveling relay gear is rotatably attached to the PTO transmission shaft, and the power of the traveling transmission shaft is transmitted to the traveling relay gear and then from the traveling relay gear to the front wheel transmission shaft. As a result, even if the traveling transmission shaft and the front wheel transmission shaft are separated in the vertical direction, the power of the traveling transmission shaft is smoothly transmitted to the front wheel transmission shaft.

[0038] In the present invention, it is preferable that a mid-PTO shaft is provided at the bottom of the transmission case, the PTO transmission shaft is provided below the traveling transmission shaft, and the power of the PTO transmission shaft is transmitted to the mid-PTO shaft.

[0039] In some tractors, a mid-PTO shaft is provided at the bottom of the transmission case in addition to the PTO transmission shaft, and the power of the PTO transmission shaft is branched and transmitted to the mid-PTO shaft. According to the present invention, the PTO transmission shaft is provided below the travel transmission shaft and close to the mid-PTO shaft, so that the transmission structure in which the power of the PTO transmission shaft is transmitted to the mid-PTO shaft is configured compactly.

[0040] In the present invention, it is preferable that inside the transmission case, there are provided a front wheel transmission shaft that is arranged in the fore-and-aft direction between the first imaginary line and the second imaginary line in a plan view, at a position lower than the PTO transmission shaft, and that transmits power to the front wheels used for driving, and a PTO relay gear that is rotatably attached to the front wheel transmission shaft, and that the power of the driving transmission shaft is transmitted to the front wheel transmission shaft, and the power of the PTO transmission shaft is transmitted to the PTO relay gear and from the PTO relay gear to the mid-PTO shaft.

[0041] In a tractor, when the front wheels are driven in addition to the rear traveling device, a front wheel transmission shaft is provided to transmit power branched from the traveling transmission shaft to the front wheels. According to the present invention, the front wheel transmission shaft is provided inside the transmission case along the front-to-rear direction, between the first and second imaginary lines in a plan view, and below the PTO transmission shaft. Power from the traveling transmission shaft is transmitted to the front wheel transmission shaft and then to the front wheels via the front wheel transmission shaft. As a result, since the front wheel transmission shaft is provided between the first and second imaginary lines in a plan view, this is advantageous in that the width of the transmission case in the left-right direction can be made small.

[0042] When the mid-PTO shaft is mounted at the bottom of the transmission case, the PTO transmission shaft and the mid-PTO shaft may be separated in the vertical direction. According to the present invention, the PTO relay gear is rotatably attached to the front wheel transmission shaft, and the power of the PTO transmission shaft is transmitted to the PTO relay gear and then from the PTO relay gear to the mid-PTO shaft. This allows the power of the PTO transmission shaft to be smoothly transmitted to the mid-PTO shaft even if the PTO transmission shaft and the mid-PTO shaft are separated in the vertical direction.

[0043] 17 is a diagram showing a first embodiment (the same applies to the following Figs. 17 and 18), showing a left side view of an electric tractor. FIG. 18 is a plan view of the electric tractor. FIG. 19 is a left side view of the vicinity of the front frame, storage frame and transmission case. FIG. 20 is a plan view of the vicinity of the front frame, storage frame and transmission case. FIG. 21 is a plan view of the storage frame. FIG. 22 is a bottom view of the storage frame. FIG. 23 is a front view of the storage frame. FIG. 24 is a rear view of the storage frame. FIG. 25 is an exploded perspective view of the storage frame. FIG. 26 is a left side view showing a linking mechanism between the brake pedal and the brake. FIG. 27 is a rear view of the vicinity of the support frame to which the steering handle and the like are attached. FIG. 28 is a plan view of the linking mechanism between the brake pedal and the brake. FIG. 29 is a longitudinal front view showing the linking mechanism between the brake pedal and the brake. FIG. 29 is a left side view of an electric tractor equipped with a front loader device. FIG. 29 is a plan view of the vicinity of the front frame, storage frame and transmission case when the front loader device is equipped. FIG. 29 is a left side view of an electric tractor equipped with a front loader device and a backhoe device. 29 is a right side view of the electric tractor showing a second embodiment (the same applies to the following figures up to 29). FIG. 30 is a plan view of the vicinity of the front frame, storage frame and transmission case. FIG. 31 is a plan view of the vicinity of the front frame, storage frame and transmission case. FIG. 32 is a plan view of the vicinity of the front frame, storage frame and transmission case. FIG. 33 is a bottom view of the storage frame. FIG. 34 is a front view of the storage frame. FIG. 35 is a rear view of the storage frame. FIG. 36 is an exploded perspective view of the storage frame. FIG. 37 is a schematic plan view showing the transmission system inside the transmission case. FIG. 38 is a rear view showing the transmission system inside the transmission case. FIG. 39 is a cross-sectional plan view of the vicinity of the first part of the transmission case and the rear part of the storage frame. FIG. 39 is a right side view showing the transmission system inside the transmission case. FIG. 31 is a left side view showing the transmission system inside the transmission case.

[0044] [First embodiment] Figures 1 to 17 show an electric tractor according to a first embodiment of the present invention, 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] (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.

[0058] 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.

[0059] 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.

[0060] 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).

[0061] 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.

[0062] (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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] 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.

[0075] 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.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] (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.

[0080] 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).

[0081] 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.

[0082] 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.

[0083] 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.

[0084] 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.

[0085] 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.

[0086] 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.

[0087] (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.

[0088] 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.

[0089] 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.

[0090] 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.

[0091] 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.

[0092] (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.

[0093] 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.

[0094] 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).

[0095] 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.

[0096] 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.

[0097] 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.

[0098] 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.

[0099] 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.

[0100] 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.

[0101] 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.

[0102] 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.

[0103] 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).

[0104] 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.

[0105] 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.

[0106] (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).

[0107] 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.

[0108] 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.

[0109] 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.

[0110] 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.

[0111] 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.

[0112] 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.

[0113] 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.

[0114] 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.

[0115] (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.

[0116] 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.

[0117] 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.

[0118] (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.

[0119] 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 .

[0120] 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.

[0121] 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.

[0122] 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.

[0123] 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.

[0124] 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.

[0125] 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.

[0126] 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.

[0127] (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.

[0128] 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.

[0129] 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.

[0130] 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.

[0131] 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.

[0132] 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.

[0133] (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.

[0134] 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.

[0135] 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 .

[0136] 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.

[0137] 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).

[0138] 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.

[0139] 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.

[0140] (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.

[0141] (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.

[0142] (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.

[0143] (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.

[0144] 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.

[0145] 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.

[0146] When the storage frame 5 is provided or when the storage frame 5 is eliminated, the battery 10, the electric motors 11 and 12, and the storage frame 5 may be positioned so that the rear end of the battery 10 is positioned slightly rearward of the front ends of the electric motors 11 and 12.

[0147] (Sixth alternative embodiment of the invention) In the storage frame 5, a bearing portion 32 may be provided on the front portion 14 of the storage frame 5, and the front wheel transmission shaft 31 may be supported by the bearing portion 32 and supported on the front portion 14 of the storage frame 5 via the bearing portion 32.

[0148] (Seventh alternative embodiment of the invention) In the storage frame 5, bearing portions 32 may be provided at the front 14 and rear 15 of the storage frame 5, and the front wheel transmission shaft 31 may be supported by the bearing portions 32 and supported at the front 14 and rear 15 of the storage frame 5 via the bearing portions 32.

[0149] Eighth 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.

[0150] (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.

[0151] (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.

[0152] 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 .

[0153] 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.

[0154] (Twelfth 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.

[0155] 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.

[0156] (Correspondence to Claims) -1 With the above configuration, the vehicle is provided with a first electric motor 11 whose output shaft 11b faces rearward and a second electric motor 12 whose output shaft 12b faces rearward. A front wheel 1 for traveling is provided, which is provided forward of the first electric motor 11 and the second electric motor 12. A transmission case 6 is provided rearward of the first electric motor 11 and the second electric motor 12, and to which a rear traveling device (rear wheel 2) is attached. A transmission mechanism is provided inside the transmission case 6, which transmits the transmitted power to the traveling device (rear wheel 2).

[0157] A front wheel transmission shaft 31 is provided to transmit power branched from the transmission mechanism to the front wheels 1. The first electric motor 11 and the second electric motor 12 are arranged side by side in the left-right direction. The front wheel transmission shaft 31 passes between the output shaft 11b of the first electric motor 11 and the output shaft 12b of the second electric motor 12 in a plan view and extends forward from the transmission case 6.

[0158] (Correspondence to Claims) -2 With the above configuration, the first electric motor 11 generates power for traveling. The second electric motor 12 generates power and hydraulic pressure to operate the installed work devices (front loader device 65 and backhoe device 75). The front wheel transmission shaft 31 is provided at a height that overlaps with the first electric motor 11 and the second electric motor 12 in a side view.

[0159] A storage frame 5 is provided to house a first electric motor 11 and a second electric motor 12. A front wheel transmission shaft 31 is provided to pass through a front portion 14 and a rear portion 15 of the storage frame 5, and a bearing portion 32 that supports the front wheel transmission shaft 31 is provided in at least one of the front portion 14 and the rear portion 15 of the storage frame 5.

[0160] An upper frame (frame 17) is provided above the front wheel transmission shaft 31 and connected in the front-to-rear direction across the front section 14 and rear section 15 of the storage frame 5. A lower frame (frame 21) is provided below the front wheel transmission shaft 31 and connected in the left-to-right direction across the right section (right lateral section 16) and left section (left lateral section 16) of the storage frame 5.

[0161] [Second embodiment] Figures 18 to 29 show an electric tractor according to a second embodiment of the present invention, and in Figures 18 to 29, 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.

[0162] 18 and 19, right and left front wheels 101 are provided at the front of a body 103, and right and left rear wheels 102 are provided at the rear of the body 103, and the body 103 is supported by the front wheels 101 and the rear wheels 102. In this case, the rear wheels 102 serve as the rear traveling device.

[0163] The machine body 103 has a front frame 104, a storage frame 105, and a transmission case 106. The front frame 104 is connected to a front part 114 of the storage frame 105, and the transmission case 106 is connected to a rear part 115 of the storage frame 105, thereby forming the machine body 103. A first electric motor 111 and a second electric motor 112 are housed in the storage frame 105 as power sources.

[0164] A front axle case 107 is attached to the front frame 104, and the right and left front wheels 101 are attached to the front axle case 107. The right and left rear wheels 102 are attached to the transmission case 106.

[0165] A driver's section 108, in which an operator sits, is provided across the accommodation frame 105 and the transmission case 106. A ROP frame 109 is attached to the transmission case 106, extends upward, and is provided behind the driver's section 108. A battery 110 that supplies power to the electric motors 111 and 112 is attached to the front frame 104, and a hood 113 that covers the battery 110 is provided.

[0166] 18 , the driving section 108 is provided with a steering wheel 133, a driver's seat 134, a speed change pedal 135, right and left brake pedals 136, and a floor 138. The floor 138 is provided below the driving section 108, and is supported by the housing frame 105, with the rear of the driving section 108 being supported by the transmission case 106.

[0167] A steering wheel 133 for steering the front wheels 101 is provided in front of the driving section 108, a driver's seat 134 is provided in the rear of the driving section 108, a speed change pedal 135 is provided on the right side of the floor 138, and right and left brake pedals 136 are provided on the left side of the steering wheel 133.

[0168] 20 to 24, the storage frame 105 has a front portion 114, a rear portion 115, a right lateral portion 116, a left lateral portion 116, and frames 117, 119, 120, and 121. In this case, the rear portion 115 of the storage frame 105 serves as the connecting portion. The right lateral portion 116 of the storage frame 105 serves as the right portion of the storage frame 105, and the left lateral portion 116 of the storage frame 105 serves as the left portion of the storage frame 105.

[0169] The front section 114 and the rear section 115 are configured as flat plates extending in the up-down and left-right directions. The right and left side sections 116 are configured as flat plates extending in the up-down and front-rear directions, but are slightly curved. The front section of the side sections 116 is connected to the right and left sections of the rear surface of the front section 114, and the rear section of the side sections 116 is connected to the right and left sections of the front surface of the rear section 115.

[0170] A frame 117 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 114 and the left-to-right center portion of the upper part of the front surface of the rear section 115. A frame 119 is connected in the left-to-right direction across the upper parts of the right and left lateral sections 116. A bracket 122 is connected between the frame 117 and the frame 119.

[0171] The right and left frames 120 are connected in the front-to-rear direction to lower portions of the right and left lateral portions 116. A frame 121 is connected in the left-to-right direction across the right and left frames 120.

[0172] 20 to 24, electric motors 111, 112 are provided side by side in the left-right direction inside the storage frame 105 (between the front portion 114 and the rear portion 115, between the right and left lateral portions 116, and between the frames 117, 119 and the frame 121). The electric motors 111, 112 are the same and have the same output.

[0173] 23 and 24 , right and left openings 115a are formed in the right and left portions of the rear portion 115 of the storage frame 105, and an opening 115b is formed in the left-right center portion of the rear portion 115 of the storage frame 105. A ring-shaped recess 115c is formed in the front portion of the rear portion 115 of the storage frame 105, concentric with the opening 115a of the rear portion 115 of the storage frame 105. In this case, opening 115b serves as a front wheel transmission opening.

[0174] 27 , flanges 111a, 112a and output shafts 111b, 112b are provided at the rear ends of the electric motors 111, 112. Ring-shaped protrusions 111c, 112c are formed on the flanges 111a, 112a of the electric motors 111, 112 concentrically with the output shafts 111b, 112b of the electric motors 111, 112. In this case, the flanges 111a, 112a of the electric motors 111, 112 form the rear parts of the electric motors 111, 112.

[0175] The protrusions 111c, 112c of the electric motors 111, 112 are fitted into the recesses 115c of the rear part 115 of the accommodating frame 105 (spigot joint structure). A sealing member 118 such as an O-ring is provided between the protrusions 111c, 112c of the electric motors 111, 112 and the recesses 115c of the rear part 115 of the accommodating frame 105.

[0176] In the above-described state, the flange portion 111a of the electric motor 111 is connected to the left portion of the front surface of the rear portion 115 of the storage frame 105, and the flange portion 112a of the electric motor 112 is connected to the right portion of the front surface of the rear portion 115 of the storage frame 105. As shown in Figures 23 and 27, the output shafts 111b and 112b of the electric motors 111 and 112 are provided at positions facing the opening 115a of the rear portion 115 of the storage frame 105 and point rearward.

[0177] As shown in Figures 19 and 27, when a virtual line L104 is assumed to pass between electric motors 111 and 112 in the fore-and-aft direction in the storage frame 105, electric motor 111 is provided on the left side of virtual line L104 in a planar view, and electric motor 112 is provided on the right side of virtual line L104 in a planar view.

[0178] (Configuration of mounting portion and inverter for mounting working device) As shown in Figures 20 to 24, on the right and left horizontal portions 116 of the storage frame 105, upper mounting portions 116a are provided at an upper part of the front part of the horizontal portion 116, facing diagonally upward, and lower mounting portions 116a are provided at a lower part of the front part of the horizontal portion 116, facing diagonally downward.

[0179] The right mounting portion 123 is connected across the mounting portion 116 a of the right horizontal portion 116 of the storage frame 105, and the left mounting portion 123 is connected across the mounting portion 116 a of the left horizontal portion 116 of the storage frame 105. As will be described later, a working device such as a front loader device 165 (see FIG. 18 ) is attached to the right and left mounting portions 123.

[0180] As shown in Figure 19, right and left inverters 124 are attached to the right and left lateral portions 116 of the storage frame 105, and are provided behind the attachment portion 123. Power from the battery 110 is supplied to the left inverter 124, and based on the operation of the speed change pedal 135 (see Figure 18), the left inverter 124 converts the DC power of the battery 110 into AC power and supplies it to the electric motor 111, causing the electric motor 111 to operate in the forward direction and the reverse direction.

[0181] Electric power from the battery 110 is supplied to the right inverter 124, which converts the DC power from the battery 110 into AC power and supplies it to the electric motor 112, thereby operating the electric motor 112. The electric motor 112 drives the hydraulic pump 161 as described below, and therefore operates in the forward direction and does not operate in the reverse direction.

[0182] 19 , the transmission case 106 has a first portion 106a, a second portion 106b, a third portion 106c, and right and left rear axle cases 106d. The rear axle case 106d is provided on the third portion 106c, and the right and left rear wheels 102 are attached to the rear axle case 106d. In this case, the first portion 106a and the second portion 106b of the transmission case 106 form the front portion of the transmission case 106, and the third portion 106c of the transmission case 106 forms the rear portion of the transmission case 106.

[0183] A first portion 106a of the transmission case 106 is connected to the rear surface of the rear portion 115 of the accommodating frame 105, and the transmission case 106 is provided rearward of the electric motors 111, 112. The first portion 106a of the transmission case 106 is open toward the front, and by connecting the first portion 106a of the transmission case 106 to the rear surface of the rear portion 115 of the accommodating frame 105, the first portion 106a of the transmission case 106 is closed by the rear portion 115 of the accommodating frame 105.

[0184] The left-right width W104 of the housing frame 105 is greater than the left-right widths W101, W102, and W103 of the transmission case 106. The left-right width W101 of the first portion 106a of the transmission case 106 is greater than the left-right width W102 of the second portion 106b of the transmission case 106. The left-right width W102 of the second portion 106b of the transmission case 106 is greater than the left-right width W103 of the third portion 106c of the transmission case 106.

[0185] 25 and 28, lubricating oil is stored inside the transmission case 106. A hydraulic multi-plate traveling clutch 139 and a hydraulic multi-plate PTO clutch 140 are provided in the right and left portions of the second portion 106b of the transmission case 106.

[0186] The travel transmission shaft 141, the PTO transmission shaft 142, and the front wheel transmission shaft 131 are provided in the longitudinal direction at the left-right central portion of the transmission case 106 across the second portion 106b and the third portion 106c of the transmission case 106.

[0187] A travel relay shaft 143 is provided along the front-to-rear direction on the left side of the second portion 106b of the transmission case 106. A gear-type transmission 144 is provided on the left side of the second portion 106b of the transmission case 106. A rear wheel differential device 145 is provided on the third portion 106c of the transmission case 106.

[0188] A PTO shaft 128 (see FIGS. 18 and 19) is provided facing rearward at the rear end of the third section 106c of the transmission case 106. A mid-PTO shaft 129 (see FIG. 18) is provided facing forward at the bottom of the third section 106c of the transmission case 106.

[0189] As will be described later, the power of the electric motor 111 is transmitted to the traveling clutch 139, and then transmitted from the traveling clutch 139 to the rear wheels 102 via the traveling relay shaft 143, the transmission 144, the traveling transmission shaft 141, and the rear wheel differential device 145. The power branched between the transmission 144 and the rear wheel differential device 145 is transmitted to the front wheel transmission shaft 131, and then from the front wheel transmission shaft 131 to the front wheels 101.

[0190] The power of the electric motor 112 is transmitted to the PTO clutch 140, and then transmitted from the PTO clutch 140 to the PTO shaft 128 via a PTO transmission shaft 142. The power branched from the PTO transmission shaft 142 is transmitted to the mid-PTO shaft 129.

[0191] (Connection configuration between electric motor and running clutch and PTO clutch) As shown in Figures 25, 26, and 27, the input shaft 125 is connected to the running clutch 139, the input shaft 126 is connected to the PTO clutch 140, and the input shafts 125 and 126 extend forward from the first part 106a of the transmission case 106.

[0192] An input shaft 125 passes through a left opening 115a in the rear portion 115 of the storage frame 105 and is splined to the output shaft 111b of the electric motor 111. An input shaft 126 passes through a right opening 115a in the rear portion 115 of the storage frame 105 and is splined to the output shaft 112b of the electric motor 112.

[0193] As a result, the power of the output shaft 111b of the electric motor 111 is transmitted to the traveling clutch 139 via the input shaft 125. The power of the output shaft 112b of the electric motor 112 is transmitted to the PTO clutch 140 via the input shaft 126.

[0194] Bearing portions 127 having bearings are provided in right and left openings 115a of the rear portion 115 of the storage frame 105. The input shafts 125, 126 pass through and are supported by the bearing portions 127, and are supported by the rear portion 115 of the storage frame 105 via the bearing portions 127. Seal members 137 are provided on the bearing portions 127, and seal members 146 are provided on the output shafts 111b, 112b of the electric motors 111, 112.

[0195] As a result, even if the lubricating oil in the transmission case 106 attempts to enter the space between the recess 115c in the rear 115 of the accommodating frame 105 and the protrusions 111c, 112c of the electric motors 111, 112 through the opening 115a and bearing portion 127 in the rear 115 of the accommodating frame 105, it is blocked by the sealing member 137.

[0196] Even if the lubricating oil in the transmission case 106 enters the aforementioned space, the sealing member 118 prevents the lubricating oil in the transmission case 106 from escaping from the aforementioned space to the outside, and the sealing member 146 prevents the lubricating oil from entering the interior of the electric motors 111, 112.

[0197] (Configuration of the transmission system to the rear wheels in the transmission case) - 1 As shown in Figures 25 and 26, the traveling transmission shaft 141, the PTO transmission shaft 142, the front wheel transmission shaft 131, and the mid-PTO shaft 129 are arranged in a vertical line along an imaginary line L103 set in the vertical direction in the center of the left and right parts of the transmission case 106.

[0198] Of the traveling transmission shaft 141, PTO transmission shaft 142, front wheel transmission shaft 131, and mid-PTO shaft 129, the traveling transmission shaft 141 is provided at the highest position. The PTO transmission shaft 142 is provided below the traveling transmission shaft 141, the front wheel transmission shaft 131 is provided below the PTO transmission shaft 142, and the mid-PTO shaft 129 is provided below the front wheel transmission shaft 131.

[0199] Assume that an imaginary line L101 extends rearward from the output shaft 111b (input shaft 125) of the electric motor 111, and an imaginary line L102 extends rearward from the output shaft 112b (input shaft 126) of the electric motor 112. The travel transmission shaft 141, the PTO transmission shaft 142, the front wheel transmission shaft 131, and the mid PTO shaft 129 are located between the imaginary lines L101 and L102 in a plan view (rear view). In this case, the imaginary line L101 is the first imaginary line, and the imaginary line L102 is the second imaginary line.

[0200] The traveling relay shaft 143 is provided at a height between the traveling transmission shaft 141 and the PTO transmission shaft 142, and is provided between the virtual line L101 and the virtual line L102 in a plan view (rear view), and is provided between the virtual line L101 and the traveling transmission shaft 141 in a plan view (rear view).

[0201] 25, 26, and 28, the transmission gear 139a of the traveling clutch 139 is engaged with the transmission gear 143a connected to the traveling relay shaft 143. The power of the traveling clutch 139 is transmitted toward the left-right center of the mission case 106 by the transmission gear 139a of the traveling clutch 139 and the transmission gear 143a of the traveling relay shaft 143, and then transmitted to the traveling relay shaft 143. In this case, the transmission gear 139a of the traveling clutch 139 and the transmission gear 143a of the traveling relay shaft 143 form a first transmission mechanism.

[0202] A speed change device 144 is provided across the traveling relay shaft 143 and the traveling transmission shaft 141. In the speed change device 144, a high-speed gear 147 rotatably attached to the traveling relay shaft 143 meshes with a transmission gear 141 a connected to the traveling transmission shaft 141, and a low-speed gear 148 rotatably attached to the traveling relay shaft 143 meshes with a transmission gear 141 b connected to the traveling transmission shaft 141. A shift member 149 is attached to the traveling relay shaft 143 by a spline structure so as to be rotatable and slidable integrally therewith.

[0203] In the transmission 144, when the shift member 149 is engaged with the high-speed gear 147, the power of the traveling relay shaft 143 is transmitted at high speed to the traveling transmission shaft 141 via the high-speed gear 147 and the transmission gear 141 a of the traveling transmission shaft 141. When the shift member 149 is engaged with the low-speed gear 148, the power of the traveling relay shaft 143 is transmitted at low speed to the traveling transmission shaft 141 via the low-speed gear 148 and the transmission gear 141 b of the traveling transmission shaft 141.

[0204] As a result, the power of the output shaft 111b of the electric motor 111 is transmitted to the rear wheels 102 via the input shaft 125, the traveling clutch 139, the traveling relay shaft 143, the speed change device 144, the traveling transmission shaft 141, and the rear wheel differential device 145. Based on the operation of the speed change pedal 135 (see FIG. 18), the electric motor 111 operates in forward and reverse directions at a stepless speed, and the electric tractor moves forward (forward operation of the electric motor 111) and backward (reverse operation of the electric motor 111).

[0205] (Brake-Related Configuration) As shown in Figure 25, a right brake 150 capable of braking the right rear wheel 102 and left and right brakes 150 capable of braking the left rear wheel 102 are provided in the third portion 106c of the transmission case 106. The right brake 150 and the right brake pedal 136 (see Figure 18) are connected via a right linkage mechanism (not shown). The left brake 150 and the left brake pedal 136 (see Figure 18) are connected via a left linkage mechanism (not shown).

[0206] When the operator of the driving section 108 steers the front wheels 101 to the right (left) using the steering handle 133, the operator depresses the right (left) brake pedal 136, which applies a brake to the right (left) rear wheels 102, thereby making a sharp turn to the right (left).

[0207] When the electric tractor is stopped from a traveling state, for example, if the operator of the driving unit 108 depresses the right and left brake pedals 136 to brake the right and left rear wheels 102, the depression of the right and left brake pedals 136 is detected and the traveling clutch 139 is disengaged. During maintenance work, for example, the operator can start and stop the electric motor 111 while keeping the traveling clutch 139 disengaged.

[0208] 19, 25, and 27, a pipe member 130 is connected in the front-to-rear direction between the rear portion 115 of the accommodation frame 105 and the front axle case 107. A front wheel transmission shaft 131 extends forward from the inside of the third portion 106c of the transmission case 106, passes through the inside of the pipe member 130, and is connected to a front wheel differential device (not shown) of the front axle case 107.

[0209] 22 and 24, the storage frame 105 has a recess 114a that is open downward and faces upward, in the left-right center of the lower part of the front part 114. As shown in Figures 22, 23, 25, and 27, in the storage frame 105, the pipe member 130 and the front wheel transmission shaft 131 are provided in the recess 114a in the front part 114 of the storage frame 105, and the front wheel transmission shaft 131 is provided in the opening 115b in the rear part 115 of the storage frame 105. The pipe member 130 and the front wheel transmission shaft 131 are provided at the position of the imaginary line L104 in a plan view.

[0210] A bearing portion 132 having a bearing is provided in an opening 115b of the rear portion 115 of the storage frame 105. The front wheel transmission shaft 131 passes through the bearing portion 132 and is supported by the bearing portion 132, and is supported by the rear portion 115 of the storage frame 105 via the bearing portion 132. The rear end portion of the pipe member 130 is attached to the bearing portion 132. In this case, the bearing portion 132 serves as the front wheel transmission bearing portion.

[0211] A seal member 151 is provided in the bearing portion 132. As a result, even if lubricating oil in the transmission case 106 attempts to enter the inside of the pipe member 130 through the opening 115b of the rear portion 115 of the housing frame 105 and the bearing portion 132, it is blocked by the seal member 151. Even if the lubricating oil in the transmission case 106 does enter the inside of the pipe member 130, the lubricating oil in the transmission case 106 cannot escape from the inside of the pipe member 130 to the outside. In this case, the seal member 151 serves as a front wheel transmission seal member.

[0212] The pipe member 130 and the front wheel transmission shaft 131 are arranged between the output shaft 111b of the electric motor 111 and the output shaft 112b of the electric motor 112 in a plan view, and are arranged in the left-right center of the storage frame 105, and are arranged directly below the frame 117 of the storage frame 105 (see Figures 20 to 24).

[0213] 22 and 23 , the pipe member 130 and the front wheel transmission shaft 131 are provided at a height that overlaps with the electric motors 111, 112 in a side view. Specifically, the pipe member 130 and the front wheel transmission shaft 131 are provided between the output shafts 111 b, 112 b of the electric motors 111, 112 and the lower ends of the electric motors 111, 112, and are provided above the frame 121 of the storage frame 105.

[0214] (Configuration of the transmission system to the front wheels in the transmission case)-2 As shown in Figures 25, 26, 28, and 29, the traveling relay gear 152 is rotatably attached to the PTO transmission shaft 142, and the transmission gear 141c connected to the traveling transmission shaft 141 is engaged with the traveling relay gear 152.

[0215] The front wheel transmission shaft 131 is attached to the switching gear 153 so as to be rotatable and slidable integrally with the front wheel transmission shaft 131. The switching gear 153 can be slid between an engagement position where it engages with the traveling relay gear 152 and a spaced position where it is spaced apart from the traveling relay gear 152.

[0216] When the switching gear 153 is operated to an engagement position where it engages with the traveling relay gear 152, the power of the traveling transmission shaft 141 is transmitted to the front wheel transmission shaft 131 via the transmission gear 141c of the traveling transmission shaft 141, the traveling relay gear 152, and the switching gear 153, and then transmitted from the front wheel transmission shaft 131 to the front wheels 101. This state is a 104-wheel drive state in which the front wheels 101 and rear wheels 102 are driven.

[0217] When the switching gear 153 is operated to a separate position away from the traveling relay gear 152, the power of the traveling transmission shaft 141 is not transmitted to the front wheel transmission shaft 131, and the front wheels 101 are not driven. This state is a rear-wheel drive state in which the rear wheels 102 are driven.

[0218] In this case, the input shaft 125, the running clutch 139, the running relay shaft 143, the transmission 144, the running transmission shaft 141 and the rear wheel differential device 145, the running relay gear 152, the switching gear 153, the front wheel transmission shaft 131, etc. constitute the transmission mechanism of the running system to the front wheels 101 and the rear wheels 102.

[0219] (Configuration of the transmission system to the PTO shaft and mid-PTO shaft in the transmission case) - 1 As shown in Figures 25, 26, and 29, transmission gears 154, 155, and 156 are provided at a height between the traveling transmission shaft 141 and the input shaft 126, and are provided between imaginary lines L101 and L102 in a plan view (rear view), and are provided between imaginary line L102 and the PTO transmission shaft 142 (traveling transmission shaft 141) in a plan view (rear view).

[0220] The transmission gear 140a of the PTO clutch 140 is engaged with the transmission gear 154. The transmission gears 155 and 156 are connected to each other so as to be rotatable as a single unit, and the transmission gears 155 and 154 are engaged with each other, and the transmission gear 156 is engaged with the transmission gear 142a connected to the PTO transmission shaft 142.

[0221] The PTO relay gear 157 and the PTO relay gear 158 are connected to each other so as to be rotatable as a unit, and the PTO relay gears 157, 158 are rotatably attached to the front wheel transmission shaft 131. A transmission gear 142b connected to the PTO transmission shaft 142 and the PTO relay gear 157 are in mesh with each other.

[0222] A transmission gear 159 is rotatably attached to the mid-PTO shaft 129, and the PTO relay gear 158 meshes with the transmission gear 159. A shift member 160 is attached to the mid-PTO shaft 129 by a spline structure so as to be rotatable and slidable integrally therewith.

[0223] 25, 26, and 29, the power of PTO clutch 140 is transmitted toward the left-right center of mission case 106 by transmission gear 140a of PTO clutch 140 and transmission gears 154, 155, and 156, then to PTO transmission shaft 142, and from PTO transmission shaft 142 to PTO shaft 128. In this case, transmission gear 140a of PTO clutch 140, transmission gear 142a of PTO transmission shaft 142, and transmission gears 154, 155, and 156 form a second transmission mechanism.

[0224] When the shift member 160 is engaged with the transmission gear 159 , the power of the PTO transmission shaft 142 is transmitted to the mid-PTO shaft 129 via the transmission gear 142 b of the PTO transmission shaft 142 , the PTO relay gears 157 and 158 , the transmission gear 159 , and the shift member 160 .

[0225] As a result, PTO clutch 140 is operated to a transmission state and a disengagement state, thereby operating and stopping PTO shaft 128 and mid-PTO shaft 129. When PTO clutch 140 is operated to a transmission state and shift member 160 is operated to separate from transmission gear 159, PTO shaft 128 is operated and mid-PTO shaft 129 is stopped.

[0226] In the electric tractor, when a work implement such as a rotary tiller (not shown) is attached to the rear of the machine body 103, the power of the PTO shaft 128 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 103 between the front wheels 101 and the rear wheels 102, the power of the mid-PTO shaft 129 is transmitted to the work implement.

[0227] In this case, the PTO clutch 140 , the PTO transmission shaft 142 , the PTO relay gears 157 , 158 , the transmission gear 159 , the shift member 160 , etc. constitute a PTO system transmission mechanism to the PTO shaft 128 and the mid-PTO shaft 129 .

[0228] 18, 19, and 25, the right portion of the first portion 106a of the transmission case 106 protrudes laterally outward to the right of the right portion of the second portion 106b of the transmission case 106. As a result, the width W101 in the left-right direction of the first portion 106a of the transmission case 106 is greater than the width W102 in the left-right direction of the second portion 106b of the transmission case 106.

[0229] The hydraulic pump 161 is attached facing rearward to the right portion of the first portion 106a of the transmission case 106. As a result, the hydraulic pump 161 is provided on the right side, which is the same side as the electric motor 112, with respect to the imaginary line L104 in a plan view. The hydraulic pump 161 is provided laterally outward from the right portion (the same side as the electric motor 112) of the second portion 106b of the transmission case 106, and is provided rearward of the right portion (the same side as the electric motor 112) of the rear portion 115 of the accommodation frame 105.

[0230] 25 and 26 , a transmission gear 162 and a transmission gear 163 are provided in the right portion inside the first portion 106a of the transmission case 106. The transmission gear 162 meshes with the transmission gear 126a connected to the input shaft 126, the transmission gear 162 meshes with the transmission gear 163, and the transmission gear 163 meshes with the input gear 161a of the hydraulic pump 161.

[0231] The power of the electric motor 112 is transmitted to the hydraulic pump 161 via the transmission gear 126a of the input shaft 126 and transmission gears 162 and 163, thereby driving the hydraulic pump 161. Because the PTO clutch 140 is provided downstream of the input shaft 126, the hydraulic pump 161 is driven by the electric motor 112 even when the PTO clutch 140 is disengaged.

[0232] (Configuration of the Filter) As shown in FIGS. 19 and 25, a lubricating oil outlet (not shown) is opened in the left portion of the second portion 106b of the transmission case 106, and a filter 164 is connected to the outlet.

[0233] The filter 164 is provided laterally outward from the left portion (opposite the electric motor 112) of the second part 106b of the transmission case 106, and is provided rearward from the left portion (opposite the electric motor 112) of the rear part 115 of the accommodating frame 105.

[0234] As shown in Figures 18, 19 and 25, a supply oil passage 174 is connected between the hydraulic pump 161 and the filter 164, and the supply oil passage 174 is provided above the second portion 106b of the transmission case 106 along the left-right direction.

[0235] Lubricating oil in the transmission case 106 passes through a filter 164 and a supply oil passage 174 and is supplied as hydraulic oil to the hydraulic pump 161. The hydraulic oil from the hydraulic pump 161 is supplied to hydraulic equipment such as a power steering device (not shown) equipped on the electric tractor, and the hydraulic equipment such as the power steering device is operated by the supplied hydraulic oil.

[0236] 18 and 19 , an electric tractor may be equipped with a front loader device 165, which is a work device. The front loader device 165 has right and left bases 166, right and left booms 167, a bucket 168, right and left boom cylinders 169, and right and left bucket cylinders 170.

[0237] When the front loader device 165 is installed, the lower part of the right base 166 of the front loader device 165 is connected to the outer lateral surface of the right mounting portion 123 of the storage frame 105, and the lower part of the left base 166 is connected to the outer lateral surface of the left mounting portion 123 of the storage frame 105.

[0238] When the base 166 of the front loader device 165 is connected to the mounting portion 123 of the storage frame 105, the front end portion of the right (left) front and rear frame 173 is connected to the lateral outer surface portion of the right (left) base 166 of the front loader device 165, and the rear end portion of the right (left) front and rear frame 173 is connected to the right (left) rear axle case 106d of the transmission case 106.

[0239] As a result, the base 166 of the front loader device 165 is sandwiched between the mounting portion 123 and the front end portion of the front and rear frames 173, and the mounting portion 123, the front end portion of the front and rear frames 173 and the base 166 of the front loader device 165 are fastened together.

[0240] The right front-rear frame 173 is provided laterally outward to the right of the right inverter 124 and the transmission case 106, and is provided laterally outward to the right of the hydraulic pump 161. The left front-rear frame 173 is provided laterally outward to the left of the left inverter 124 and the transmission case 106, and is provided laterally outward to the left of the filter 164.

[0241] 18 and 19 , a control valve unit 171 provided with a plurality of electromagnetically operated control valves is attached to the front of the right front / rear frame 173, and a cover 175 that covers the control valve unit 171 is attached to the right front / rear frame 173. An oil passage 176 is connected between the hydraulic pump 161 and the control valve unit 171, and hydraulic oil from the hydraulic pump 161 is supplied to the control valve unit 171. In this case, the control valve unit 171 serves as a control valve.

[0242] Right and left fenders 177 are provided on the right and left parts of the driver's section 108, above the right and left rear wheels 102. An operating lever 172 is provided at the front of the upper part of the right fender 177.

[0243] As a result, the operating lever 172 is provided on the right side of the left-right center of the driving unit 108 in a plan view, and is provided on the right side (the same side as the electric motor 112) of the left-right center of the driving unit 108 in a plan view. The left-right center of the driving unit 108 and the virtual line L104 are in approximately the same position in a plan view.

[0244] A position sensor (not shown) that detects the operating position of the operating lever 172 is provided on the right fender 177, and the control valve of the control valve unit 171 is operated based on the operation of the operating lever 172. In this case, the operating lever 172 is a manual operating tool.

[0245] The operator in the driver's seat 134 operates the operating lever 172 with his right hand to operate the control valve of the control valve unit 171. As a result, hydraulic oil from the hydraulic pump 161 is supplied to and discharged from the boom cylinder 169 and bucket cylinder 170 of the front loader device 165 via the control valve unit 171, and the boom 167 and bucket 168 of the front loader device 165 are operated.

[0246] (First Alternative Embodiment of the Invention) The storage frame 105 may be eliminated, and only the flat rear portion 115 (connecting portion) may be provided.

[0247] According to this configuration, the rear section 115 (connecting section) may be connected to the lower part of the floor 138. The front frame 104 may extend rearward beneath the floor 138 and be connected to the transmission case 106, with the rear section 115 (connecting section) being connected to the front frame 104. According to this configuration, the electric motors 111, 112 are connected to the front section of the rear section 115 (connecting section), and the transmission case 106 is connected to the rear section of the rear section 115 (connecting section). A base 166 of the front loader device 165 may be connected to the front frame 104.

[0248] (Second alternative embodiment of the invention) Since electric motor 112 may require a greater output than electric motor 111, which generates power for traveling, electric motor 112 may be configured to have a greater output than electric motor 111.

[0249] Third Alternative Embodiment of the Invention The electric motor 112 may be configured to transmit power to the PTO shaft 128 and the mid-PTO shaft 129 but not to drive the hydraulic pump 161 .

[0250] According to this configuration, the hydraulic pump 161 may be configured to be driven by an electric motor (not shown) separate from the electric motors 111, 112. The hydraulic pump 161 may be configured to be driven by the electric motor 111. In this case, the control valve unit 171 may be attached to the left front / rear frame 173, and the operating lever 172 may be attached to the left fender 177.

[0251] (Fourth Alternative Embodiment of the Invention) The mid-PTO shaft 129 may be eliminated. According to this configuration, the travel transmission shaft 141 may be provided below the PTO transmission shaft 142.

[0252] (Fifth Alternative Embodiment of the Invention) The front wheel transmission shaft 131 may be provided above the traveling transmission shaft 141. Between the imaginary lines L101 and L102 in a plan view, the front wheel transmission shaft 131 may be provided between the traveling transmission shaft 141 and the imaginary line L101 in a plan view, or may be provided between the traveling transmission shaft 141 and the imaginary line L102 in a plan view.

[0253] Sixth Modification of the Invention When the electric motors 111 and 112 are arranged side by side in the left-right direction, the electric motor 111 may be arranged on the right and the electric motor 112 may be arranged on the left.

[0254] According to this configuration, the traveling clutch 139 (imaginary line L101), traveling relay shaft 143, and speed change device 144 are provided on the right side of the traveling transmission shaft 141 and the PTO transmission shaft 142 in a plan view. The PTO clutch 140 (imaginary line L102) and transmission gears 154, 155, 156 are provided on the left side of the traveling transmission shaft 141 and the PTO transmission shaft 142 in a plan view.

[0255] (Seventh alternative embodiment of the invention) When the storage frame 105 is provided or when the storage frame 105 is eliminated, the battery 110, the electric motors 111 and 112, and the storage frame 105 may be positioned so that the rear end of the battery 110 is positioned slightly rearward of the front ends of the electric motors 111 and 112.

[0256] Eighth Alternative Embodiment of the Invention Front portions of the electric motors 111, 112 may be connected to the front portion 114 of the storage frame 105. With this configuration, the casings of the electric motors 111, 112 become part of the storage frame 105, thereby improving the rigidity of the storage frame 105.

[0257] (Ninth Alternative Embodiment of the Invention) The output shafts 111b, 112b of the electric motors 111, 112 may be configured to extend rearward, pass through an opening 115a in the rear portion 115 of the accommodation frame 105, enter the inside of the transmission case 106, and be coupled to an input shaft (not shown) of the traveling clutch 139 and an input shaft (not shown) of the PTO clutch 140. According to this configuration, the output shafts 111b, 112b of the electric motors 111, 112 pass through the bearing portion 127 and are supported by the bearing portion 127.

[0258] Tenth Alternative Embodiment of the Invention When the front loader device 165 is not installed, the front and rear frames 173 may be connected across the mounting portion 123 of the storage frame 105 and the rear axle case 106 d of the transmission case 106 .

[0259] Eleventh Alternative Embodiment of the Invention The vehicle may be configured as a two-wheel drive vehicle instead of a four-wheel drive vehicle. In this configuration, the pipe member 130, the front wheel transmission shaft 131, the bearing 132, the seal member 151, the opening 115b in the rear portion 115 of the storage frame 105, and the recess 114a in the front portion 114 are eliminated.

[0260] Twelfth Alternative Embodiment of the Invention Instead of the rear wheels 102, crawler-type right and left traveling devices (not shown) may be attached to the transmission case 106.

[0261] The electric tractor may not only be equipped with the electric motors 111 and 112 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 111 and 112 as a power source.

[0262] (Correspondence to Claims) -1 With the above configuration, a first electric motor 111 is provided which generates power for traveling and has an output shaft 111b facing rearward. A second electric motor 112 is provided which generates power and hydraulic pressure to operate the attached working device (front loader device 165) and has an output shaft 112b facing rearward. The first electric motor 111 and the second electric motor 112 are arranged side by side in the left-right direction. A transmission case 106 is provided rearward of the first electric motor 111 and the second electric motor 112, and to which the rear traveling device (rear wheels 102) is attached.

[0263] Inside the transmission case 106, a traveling transmission shaft 141 is provided, which is arranged along the fore-and-aft direction between a first imaginary line (imaginary line L101) extending rearward from the output shaft 111b of the first electric motor 111 in a plan view and a second imaginary line (imaginary line L102) extending rearward from the output shaft 112b of the second electric motor 112, and transmits power to the traveling device (rear wheels 102).

[0264] Inside the transmission case 106, a PTO transmission shaft 142 is provided, which is arranged in the fore-and-aft direction between the first virtual line (virtual line L101) and the second virtual line (virtual line L102) in a plan view, at a position above or below the traveling transmission shaft 141, and transmits power to the work device (front loader device 165).

[0265] A first transmission mechanism (a transmission gear 139a of the traveling clutch 139 and a transmission gear 143a of the traveling relay shaft 143) is provided inside the transmission case 106, which transmits the power of the output shaft 111b of the first electric motor 111 toward the left-right center of the transmission case 106 and transmits it to the traveling transmission shaft 141. A second transmission mechanism (a transmission gear 140a of the PTO clutch 140, a transmission gear 142a of the PTO transmission shaft 142, and transmission gears 154, 155, 156) is provided inside the transmission case 106, which transmits the power of the output shaft 112b of the second electric motor 112 toward the left-right center of the transmission case 106 and transmits it to the PTO transmission shaft 142.

[0266] (Correspondence to Claims) -2 With the above configuration, the rear portion (third portion 106c) of the transmission case 106 that accommodates the traveling transmission shaft 141 and the PTO transmission shaft 142 in the transmission case 106 and the front portion (first portion 106a and second portion 106b) that accommodates the first transmission mechanism (transmission gear 139a of the traveling clutch 139, transmission gear 143a of the traveling relay shaft 143) and the second transmission mechanism (transmission gear 140a of the PTO clutch 140, transmission gear 142a of the PTO transmission shaft 142, transmission gears 154, 155, 156) in the transmission case 106 have a left-right width W103 that is smaller than the left-right widths W101, W102 of the front portion (first portion 106a and second portion 106b) of the transmission case 106.

[0267] A traveling relay shaft 143 is provided inside the transmission case 106, the traveling relay shaft 143 being arranged in the front-to-rear direction between a first imaginary line (imaginary line L101) and a second imaginary line (imaginary line L102) in a plan view, and a speed change device 144 being provided between the traveling relay shaft 143 and the traveling transmission shaft 141. Power from the output shaft 111b of the first electric motor 111 is transmitted from a first transmission mechanism (transmission gear 139a of the traveling clutch 139 and transmission gear 143a of the traveling relay shaft 143) to the traveling relay shaft 143, and then from the traveling relay shaft 143 to the traveling transmission shaft 141 through the speed change device 144. The traveling relay shaft 143 is provided between the first imaginary line (imaginary line L101) and the traveling transmission shaft 141 in a plan view.

[0268] Inside the transmission case 106, a front wheel transmission shaft 131 is provided, which is disposed in the front-to-rear direction between a first imaginary line (imaginary line L101) and a second imaginary line (imaginary line L102) in a plan view, at a position above or below the traveling transmission shaft 141, and transmits power to the front wheels 101 for traveling. The power of the traveling transmission shaft 141 is transmitted to the front wheel transmission shaft 131.

[0269] The PTO transmission shaft 142 is provided below the traveling transmission shaft 141, and the front wheel transmission shaft 131 is provided below the PTO transmission shaft 142. A traveling relay gear 152 is rotatably attached to the PTO transmission shaft 142. The power of the traveling transmission shaft 141 is transmitted to the traveling relay gear 152, and then from the traveling relay gear 152 to the front wheel transmission shaft 131.

[0270] (Correspondence to Claims)-3 With the above configuration, there is provided a mid-PTO shaft 129 provided at the bottom of the transmission case 106. The PTO transmission shaft 142 is provided below the travel transmission shaft 141, and the power of the PTO transmission shaft 142 is transmitted to the mid-PTO shaft 129.

[0271] A front wheel transmission shaft 131 is provided inside the transmission case 106, extending in the front-to-rear direction in a position lower than the PTO transmission shaft 142 between a first imaginary line (imaginary line L101) and a second imaginary line (imaginary line L102) in a plan view, and transmits power to the front wheels 101 used for traveling. PTO relay gears 157, 158 are rotatably attached to the front wheel transmission shaft 131. The power of the traveling transmission shaft 141 is transmitted to the front wheel transmission shaft 131. The power of the PTO transmission shaft 142 is transmitted to the PTO relay gears 157, 158, and then from the PTO relay gears 157, 158 to the mid-PTO shaft 129.

[0272] The present invention can be applied to an electric tractor.

[0273] REFERENCE SIGNS LIST 1 Front wheel 2 Rear wheel (rear traveling device) 5 Storage frame 6 Transmission case 11 Electric motor (first electric motor) 11b Output shaft of electric motor (first electric motor) 12 Electric motor (second electric motor) 11b Output shaft of electric motor (first electric motor) 14 Front part of storage frame 15 Rear part of storage frame 16 Side part (right part) (left part) of storage frame 17 Frame (upper frame) 21 Frame (lower frame) 31 Front wheel transmission shaft 32 Bearing part 65 Front loader device (working device) 75 Backhoe device (working device) 101 Front wheel 102 Rear wheel (rear traveling device) 106 Transmission case 106a First part of transmission case (front part of transmission case) 106b Second part of transmission case (front part of transmission case) 106c Third part of transmission case (rear part of transmission case) 111 Electric motor 111b Electric motor output shaft 112 Electric motor 112b Electric motor output shaft 129 Mid PTO shaft 131 Front wheel transmission shaft 139a Traveling clutch transmission gear (first transmission mechanism) 140a PTO clutch transmission gear (second transmission mechanism) 141 Traveling transmission shaft 142 PTO transmission shaft 142a PTO transmission shaft transmission gear (second transmission mechanism) 143 Traveling relay shaft 143a Traveling relay shaft transmission gear (first transmission mechanism) 144 Speed ​​change device 152 Traveling relay gear 154 Transmission gear (second transmission mechanism) 155 Transmission gear (second transmission mechanism) 156 Transmission gear (second transmission mechanism) 157 PTO relay gear 158 PTO relay gear 165 Front loader device (working device) L101 Virtual line (first virtual line) L102 Virtual line (second virtual line) W101 Left-right width of first portion of transmission case (left-right width of front part of transmission case) W102 Left-right width of second portion of transmission case (left-right width of front part of transmission case) W103 Left-right width of third portion of transmission case (left-right width of rear part of transmission case)

Claims

1. A first electric motor with an output shaft facing rearward, a second electric motor with an output shaft facing rearward, front wheels for traveling provided in front of the first and second electric motors, a transmission case provided behind the first and second electric motors and to which a rear traveling device is attached, a transmission mechanism provided inside the transmission case for transmitting the transmitted power to the traveling device, and a front wheel transmission shaft for transmitting the power branched from the transmission mechanism to the front wheels. The first and second electric motors are arranged side by side along the left-right direction, and the front wheel transmission shaft extends forward from the transmission case through between the output shafts of the first and second electric motors in a plan view. An electric tractor.

2. The first electric motor generates power for traveling, and the second electric motor generates power and hydraulic pressure for operating the equipped work device. The electric tractor according to claim 1.

3. The front wheel transmission shaft is provided at a height overlapping the first and second electric motors in a side view. The electric tractor according to claim 1 or 2.

4. An accommodation frame for accommodating the first and second electric motors is provided. The front wheel transmission shaft is provided so as to pass through the front and rear portions of the accommodation frame, and a bearing portion for supporting the front wheel transmission shaft is provided on at least one of the front and rear portions of the accommodation frame. The electric tractor according to any one of claims 1 to 3.

5. An upper frame is provided above the front wheel transmission shaft and is connected in the front-rear direction across the front and rear portions of the accommodation frame. The electric tractor according to claim 4.

6. A lower frame is provided below the front wheel transmission shaft and is connected in the left-right direction across the right and left portions of the accommodation frame. The electric tractor according to claim 4.

7. A first electric motor that generates power for traveling and has an output shaft facing rearward, and a second electric motor that generates power and hydraulic pressure for operating a mounted work device and has an output shaft facing rearward are provided. The first electric motor and the second electric motor are arranged side by side along the left - right direction. A transmission case is provided behind the first electric motor and the second electric motor, and a rear traveling device is attached thereto. Inside the transmission case, between a first virtual line extending rearward from the output shaft of the first electric motor in plan view and a second virtual line extending rearward from the output shaft of the second electric motor, a traveling transmission shaft is provided along the front - rear direction to transmit power to the traveling device, and a PTO transmission shaft is provided along the front - rear direction at a position above or below the traveling transmission shaft between the first virtual line and the second virtual line in plan view to transmit power to the work device. A first transmission mechanism that transmits the power of the output shaft of the first electric motor toward the left - right center of the transmission case and then to the traveling transmission shaft, and a second transmission mechanism that transmits the power of the output shaft of the second electric motor toward the left - right center of the transmission case and then to the PTO transmission shaft are provided. An electric tractor is provided with these components.

8. In the rear part of the transmission case that houses the traveling transmission shaft and the PTO transmission shaft, and the front part of the transmission case that houses the first transmission mechanism and the second transmission mechanism, the lateral width in the left - right direction of the rear part of the transmission case is smaller than the lateral width in the left - right direction of the front part of the transmission case. The electric tractor according to claim 7.

9. Inside the transmission case, a traveling relay shaft provided along the front - rear direction between the first virtual line and the second virtual line in plan view, and a transmission device provided across the traveling relay shaft and the traveling transmission shaft are provided. The power of the output shaft of the first electric motor is transmitted from the first transmission mechanism to the traveling relay shaft, and then from the traveling relay shaft through the transmission device to the traveling transmission shaft. The electric tractor according to claim 7 or 8.

10. The traveling relay shaft is provided between the first virtual line and the traveling transmission shaft in plan view. The electric tractor according to claim 9.

11. Inside the transmission case, between the first virtual line and the second virtual line in plan view, a front-wheel transmission shaft is provided at a position above or below the traveling transmission shaft along the front-rear direction, and transmits power to the front wheels for traveling. The electric tractor according to any one of claims 7 to 10, wherein the power of the traveling transmission shaft is transmitted to the front-wheel transmission shaft.

12. The PTO transmission shaft is provided below the traveling transmission shaft, the front-wheel transmission shaft is provided below the PTO transmission shaft, a traveling relay gear rotatably attached to the PTO transmission shaft is provided, and the power of the traveling transmission shaft is transmitted to the traveling relay gear and then from the traveling relay gear to the front-wheel transmission shaft. The electric tractor according to claim 11.

13. A mid-PTO shaft provided at the bottom of the transmission case is provided, the PTO transmission shaft is provided below the traveling transmission shaft, and the power of the PTO transmission shaft is transmitted to the mid-PTO shaft. The electric tractor according to any one of claims 7 to 12.

14. Inside the transmission case, between the first virtual line and the second virtual line in plan view, a front-wheel transmission shaft is provided at a position below the PTO transmission shaft along the front-rear direction, and transmits power to the front wheels for traveling, and a PTO relay gear rotatably attached to the front-wheel transmission shaft is provided. The power of the traveling transmission shaft is transmitted to the front-wheel transmission shaft, and the power of the PTO transmission shaft is transmitted to the PTO relay gear and then from the PTO relay gear to the mid-PTO shaft. The electric tractor according to claim 13.

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