Electrical tractor

Abstract

This electrical tractor comprises a flat-plate-like coupling part 15 provided between electrical motors 11, 12 and a transmission case 6 in the vertical and horizontal directions. Rear parts of the electrical motors 11, 12 are coupled to the front surface part of the coupling part 15, and the front parts 6a, 6b of the transmission case 6 are coupled to the rear surface part of the coupling part 15. Openings 15a, which are provided through output shafts 11b, 12b of the electrical motors 11, 12 or input shafts 25, 26 of a transmission mechanism and which are for coupling the output shafts 11b, 12b and the input shafts 25, 26, are provided in the coupling part 15. Seal members 37 are provided in the openings 15a.

Description

electric tractor

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

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

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

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

[0005] In the field of tractors, electric tractors have been proposed that are equipped with an electric motor that generates power for traveling, and an electric motor that generates power and hydraulic pressure to operate the equipped implements. The object of the present invention is to provide a configuration in an electric tractor that maintains appropriate power transmission from the electric motor to the transmission mechanism of the transmission case.

[0006] The electric tractor of the present invention comprises an electric motor that generates power for traveling or power and hydraulic pressure to operate an equipped work device, a transmission case that is located rearward of the electric motor and has a transmission mechanism installed inside and lubricating oil stored inside, a flat connecting portion that is located between the electric motor and the transmission case and that is arranged in the vertical and horizontal directions, the rear of the electric motor is connected to the front portion of the connecting portion and the front of the transmission case is connected to the rear portion of the connecting portion, an opening is provided in the connecting portion for connecting the output shaft and the input shaft through the output shaft of the electric motor or the input shaft of the transmission mechanism, and a sealing member is provided in the opening to prevent lubricating oil in the transmission case from flowing through the opening toward the electric motor.

[0007] According to the present invention, a flat connecting portion is provided between the electric motor and the transmission case, the rear portion of the electric motor is connected to the front portion of the connecting portion, and the front portion of the transmission case is connected to the rear portion of the connecting portion. The output shaft of the electric motor and the input shaft of the transmission mechanism of the transmission case are connected through an opening in the connecting portion, and power from the output shaft of the electric motor is transmitted to the input shaft of the transmission mechanism of the transmission case.

[0008] According to the present invention, a seal member is provided at the opening of the connecting portion to prevent lubricating oil in the transmission case from flowing through the opening of the connecting portion toward the electric motor, and the electric motor and the interior of the transmission case are separated by the connecting portion. This prevents damage to the electric motor due to lubricating oil in the transmission case flowing to the electric motor, and prevents a decrease in lubricating oil in the transmission case, thereby maintaining appropriate power transmission from the electric motor to the transmission mechanism of the transmission case.

[0009] In the present invention, it is preferable that the front portion of the transmission case is open toward the front and connected to the rear surface of the connecting portion, thereby closing the front portion of the transmission case by the connecting portion.

[0010] According to the present invention, the connecting portion has the function of connecting the electric motor and the transmission case and the function of acting as a lid that closes the front part of the transmission case, thereby simplifying and reducing the weight of the connecting structure between the electric motor and the transmission case.

[0011] In the present invention, it is preferable that a bearing portion is provided in the opening, and the input shaft passes through the opening and is supported by the bearing portion, protrudes from the connecting portion toward the electric motor, and is connected to the output shaft.

[0012] According to the present invention, in a configuration in which the front portion of the transmission case is closed by the connecting portion, the input shaft of the transmission mechanism of the transmission case is supported by a bearing portion provided in the opening of the connecting portion, protrudes from the connecting portion toward the electric motor, and is connected to the output shaft of the electric motor. This is advantageous in that even in a configuration in which the front portion of the transmission case is open forward, the input shaft of the transmission mechanism of the transmission case is stably supported by the transmission mechanism and the bearing portion of the connecting portion, thereby maintaining appropriate power transmission from the electric motor to the transmission mechanism of the transmission case.

[0013] In the present invention, it is preferable that the seal member is provided in the bearing portion.

[0014] According to the present invention, the seal member is provided at the bearing portion of the connecting portion, which is advantageous in terms of simplifying the structure for connecting the electric motor and the transmission case.

[0015] In the present invention, it is preferable that a housing frame that houses the electric motor is provided, and the connecting portion is a rear portion of the housing frame.

[0016] According to the present invention, a storage frame is provided to house an electric motor, with the rear of the electric motor connected to the front portion of the rear portion (connection portion) of the storage frame, and the front of the transmission case connected to the rear portion (connection portion) of the storage frame. The storage frame is configured to have sufficient strength because it houses the electric motor, which is a heavy object. The transmission case is also configured to have sufficient strength. As a result, by connecting the storage frame, which has sufficient strength, and the transmission case, which also has sufficient strength, the overall rigidity of the electric tractor is improved.

[0017] In the present invention, it is preferable that the vehicle is provided with a front wheel for running that is located forward of the electric motor, a running device attached to the transmission case, a front wheel transmission opening provided at the connecting portion, and a front wheel transmission shaft that extends from the transmission case through the front wheel transmission opening toward the front wheel, and that the power of the electric motor is transmitted from the transmission mechanism to the running device and the front wheel transmission shaft, and from the front wheel transmission shaft to the front wheel, and that a front wheel transmission seal member is provided in the front wheel transmission opening to prevent lubricating oil in the transmission case from flowing toward the electric motor through the front wheel transmission opening.

[0018] In the case of an all-wheel drive vehicle such as a four-wheel drive vehicle, power may be transmitted from the transmission mechanism of the transmission case to the running gear behind the transmission case and to the front wheels. In this case, a front wheel transmission shaft that transmits power to the front wheels is provided between the transmission mechanism of the transmission case and the front wheels.

[0019] According to the present invention, the front wheel transmission shaft extends from the transmission case toward the front wheels through the front wheel transmission opening of the connecting part, and a front wheel transmission seal member is provided at the front wheel transmission opening of the connecting part to prevent lubricating oil in the transmission case from flowing through the front wheel transmission opening of the connecting part toward the electric motor. This prevents damage to the electric motor due to lubricating oil in the transmission case flowing to the electric motor and prevents a decrease in lubricating oil in the transmission case, which is advantageous in terms of maintaining appropriate transmission of power from the transmission mechanism of the transmission case to the front wheels.

[0020] In the present invention, it is preferable that a front wheel transmission bearing portion is provided in the front wheel transmission opening, and the front wheel transmission shaft passes through the front wheel transmission opening and is supported by the front wheel transmission bearing portion.

[0021] According to the present invention, the front wheel transmission shaft is stably supported by the front wheel transmission bearing portion provided in the front wheel transmission opening of the connecting portion, which is advantageous in terms of properly maintaining transmission from the transmission mechanism of the transmission case to the front wheels.

[0022] In the present invention, it is preferable that the front wheel transmission seal member is provided in the front wheel transmission bearing portion.

[0023] According to the present invention, the front wheel transmission seal member is provided at the front wheel transmission bearing portion of the connecting portion, which is advantageous in terms of simplifying the structure for connecting the electric motor and the transmission case.

[0024] FIG. 1 is a right side view of an electric tractor. FIG. 2 is a plan view of the vicinity of the front frame, storage frame and transmission case. FIG. 3 is a plan view of the storage frame. FIG. 4 is a bottom view of the storage frame. FIG. 5 is a front view of the storage frame. FIG. 6 is a rear view of the storage frame. FIG. 7 is an exploded perspective view of the storage frame. FIG. 8 is a schematic plan view showing the transmission system inside the transmission case. FIG. 9 is a rear view showing the transmission system inside the transmission case. FIG. 10 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. 11 is a right side view showing the transmission system inside the transmission case. FIG. 12 is a left side view showing the transmission system inside the transmission case.

[0025] Figures 1 to 12 show an electric tractor, and in Figures 1 to 12, F indicates the forward direction, B indicates the backward direction, U indicates the upward direction, D indicates the downward direction, R indicates the rightward direction, and L indicates the leftward direction.

[0026] 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.

[0027] The machine body 3 has a front frame 4, a housing frame 5, and a transmission case 6. The front frame 4 is connected to a front portion 14 of the housing frame 5, and the transmission case 6 is connected to a rear portion 15 of the housing frame 5, thereby forming the machine body 3. A first electric motor 11 and a second electric motor 12 are housed in the housing frame 5 as power sources.

[0028] 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.

[0029] 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.

[0030] 1 , the driving section 8 is provided with a steering wheel 33, a driver's seat 34, a speed change pedal 35, right and left brake pedals 36, and a floor 38. The floor 38 is provided below the driving section 8, and is supported by the housing frame 5, with the rear of the driving section 8 being supported by the transmission case 6.

[0031] A steering handle 33 for steering the front wheels 1 is provided in front of the driving section 8, a driver's seat 34 is provided in the rear of the driving section 8, a speed change pedal 35 is provided on the right side of the floor 38, and right and left brake pedals 36 are provided on the left side of the steering handle 33.

[0032] 3 to 7 , the storage frame 5 has a front portion 14, a rear portion 15, a right lateral portion 16, a left lateral portion 16, and frames 17, 19, 20, and 21. In this case, the rear portion 15 of the storage frame 5 serves as the connecting portion. The right lateral portion 16 of the storage frame 5 serves as the right portion of the storage frame 5, and the left lateral portion 16 of the storage frame 5 serves as the left portion of the storage frame 5.

[0033] 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.

[0034] A frame 17 is connected in the front-to-rear direction across the left-to-right central portion of the upper part of the rear surface of the front section 14 and the left-to-right central portion of the upper part of the front surface of the rear section 15. A 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 between the frame 17 and the frame 19.

[0035] The right and left frames 20 are connected in the front-to-rear direction to lower portions of the right and left lateral portions 16. A frame 21 is connected in the left-to-right direction across the right and left frames 20.

[0036] 3 to 7, 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.

[0037] 6 and 7, right and left openings 15a are formed in the right and left portions of the rear portion 15 of the storage frame 5, and an opening 15b is formed in the left-right center portion of the rear portion 15 of the storage frame 5. A ring-shaped recess 15c is formed in the front portion of the rear portion 15 of the storage frame 5, concentric with the opening 15a of the rear portion 15 of the storage frame 5. In this case, opening 15b serves as a front wheel transmission opening.

[0038] 10 , flange portions 11a, 12a and output shafts 11b, 12b are provided at the rear ends of the electric motors 11, 12. Ring-shaped protrusions 11c, 12c are formed on the flange portions 11a, 12a of the electric motors 11, 12 concentrically with the output shafts 11b, 12b of the electric motors 11, 12. In this case, the flange portions 11a, 12a of the electric motors 11, 12 form the rear portions of the electric motors 11, 12.

[0039] The protrusions 11c, 12c of the electric motors 11, 12 are fitted into the recesses 15c of the rear part 15 of the accommodating frame 5 (spigot joint structure). A sealing member 18 such as an O-ring is provided between the protrusions 11c, 12c of the electric motors 11, 12 and the recesses 15c of the rear part 15 of the accommodating frame 5.

[0040] In the above-described state, the flange portion 11a 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, and the flange portion 12a 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. As shown in Figures 6 and 10, the output shafts 11b and 12b of the electric motors 11 and 12 are provided at positions facing the opening 15a of the rear portion 15 of the storage frame 5 and point rearward.

[0041] As shown in Figures 2 and 10, when an imaginary line L4 is assumed to pass between the electric motors 11 and 12 in the front-to-rear direction in the storage frame 5, the electric motor 11 is provided on the left side of the imaginary line L4 in a plan view, and the electric motor 12 is provided on the right side of the imaginary line L4 in a plan view.

[0042] (Configuration of mounting portion and inverter for mounting working device) As shown in Figures 3 to 7, on the right and left horizontal portions 16 of the storage frame 5, upper mounting portions 16a are provided on the upper front portion of the horizontal portion 16, facing diagonally upward, and lower mounting portions 16a are provided on the lower front portion of the horizontal portion 16, facing diagonally downward.

[0043] The right mounting portion 23 is connected across the mounting portion 16 a of the right horizontal portion 16 of the storage frame 5, and 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 work device such as a front loader device 65 (see FIG. 1 ) is attached to the right and left mounting portions 23.

[0044] As shown in Figure 2, right and left inverters 24 are attached to the right and left lateral portions 16 of the storage frame 5, and are provided behind the attachment portion 23. Power from the battery 10 is supplied to the left inverter 24, and based on operation of the speed change pedal 35 (see Figure 1), the left inverter 24 converts the DC power of the battery 10 into AC power and supplies it to the electric motor 11, causing the electric motor 11 to operate in the forward direction and the reverse direction.

[0045] 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 the hydraulic pump 61 as described below, and therefore operates in the forward direction and does not operate in the reverse direction.

[0046] 2, the transmission case 6 has a first portion 6a, a second portion 6b, a third portion 6c, and right and left rear axle cases 6d. The rear axle cases 6d are provided on the third portion 6c, and the right and left rear wheels 2 are attached to the rear axle cases 6d. In this case, the first portion 6a and the second portion 6b of the transmission case 6 form the front portion of the transmission case 6, and the third portion 6c of the transmission case 6 forms the rear portion of the transmission case 6.

[0047] A first portion 6a of the transmission case 6 is connected to the rear surface of the rear portion 15 of the accommodating frame 5, and the transmission case 6 is provided rearward of the electric motors 11, 12. The first portion 6a of the transmission case 6 is open toward the front, and by connecting the first portion 6a of the transmission case 6 to the rear surface of the rear portion 15 of the accommodating frame 5, the first portion 6a of the transmission case 6 is closed by the rear portion 15 of the accommodating frame 5.

[0048] The left-right width W4 of the housing frame 5 is greater than the left-right widths W1, W2, and W3 of the transmission case 6. The left-right width W1 of the first portion 6a of the transmission case 6 is greater than the left-right width W2 of the second portion 6b of the transmission case 6. The left-right width W2 of the second portion 6b of the transmission case 6 is greater than the left-right width W3 of the third portion 6c of the transmission case 6.

[0049] 8 and 9 , lubricating oil is stored inside the transmission case 6. A hydraulic multi-plate traveling clutch 39 and a hydraulic multi-plate PTO clutch 40 are provided in the right and left portions of the second portion 6 b of the transmission case 6.

[0050] The travel transmission shaft 41, the PTO transmission shaft 42, and the front wheel transmission shaft 31 are provided in the longitudinal direction at the left-right central portion of the transmission case 6 across the second portion 6b and the third portion 6c of the transmission case 6.

[0051] A travel relay shaft 43 is provided along the front-to-rear direction on the left side of the second portion 6b of the transmission case 6. A gear-type transmission 44 is provided on the left side of the second portion 6b of the transmission case 6. A rear wheel differential device 45 is provided on the third portion 6c of the transmission case 6.

[0052] A PTO shaft 28 (see FIGS. 1 and 2) is provided facing rearward at the rear end of the third portion 6 c of the transmission case 6. A mid-PTO shaft 29 (see FIG. 1) is provided facing forward at the bottom of the third portion 6 c of the transmission case 6.

[0053] As will be described later, the power of the electric motor 11 is transmitted to the traveling clutch 39, and then transmitted from the traveling clutch 39 to the rear wheels 2 via the traveling relay shaft 43, the transmission 44, the traveling transmission shaft 41, and the rear wheel differential device 45. The power branched between the transmission 44 and the rear wheel differential device 45 is transmitted to the front wheel transmission shaft 31, and then from the front wheel transmission shaft 31 to the front wheels 1.

[0054] The power of the electric motor 12 is transmitted to the PTO clutch 40, and then transmitted from the PTO clutch 40 to the PTO shaft 28 via a PTO transmission shaft 42. The power branched from the PTO transmission shaft 42 is transmitted to the mid-PTO shaft 29.

[0055] (Connection configuration between electric motor and running clutch and PTO clutch) As shown in Figures 8, 9, and 10, the input shaft 25 is connected to the running clutch 39, the input shaft 26 is connected to the PTO clutch 40, and the input shafts 25 and 26 extend forward from the first part 6a of the transmission case 6.

[0056] An input shaft 25 passes through a left opening 15a in the rear portion 15 of the storage frame 5 and is connected to the output shaft 11b of the electric motor 11 by a spline structure. An input shaft 26 passes through a right opening 15a in the rear portion 15 of the storage frame 5 and is connected to the output shaft 12b of the electric motor 12 by a spline structure.

[0057] As a result, the power of the output shaft 11b of the electric motor 11 is transmitted to the traveling clutch 39 via the input shaft 25. The power of the output shaft 12b of the electric motor 12 is transmitted to the PTO clutch 40 via the input shaft 26.

[0058] Bearing portions 27 having bearings are provided in the right and left openings 15a of the rear portion 15 of the storage frame 5. The input shafts 25, 26 pass through and are supported by the bearing portions 27, and are supported by the rear portion 15 of the storage frame 5 via the bearing portions 27. Seal members 37 are provided in the bearing portions 27, and seal members 46 are provided on the output shafts 11b, 12b of the electric motors 11, 12.

[0059] As a result, even if the lubricating oil in the transmission case 6 tries to enter the space between the recess 15c in the rear part 15 of the accommodating frame 5 and the protrusions 11c, 12c of the electric motors 11, 12 through the opening 15a and bearing part 27 in the rear part 15 of the accommodating frame 5, it is blocked by the sealing member 37.

[0060] Even if the lubricating oil in the transmission case 6 enters the aforementioned space, the sealing member 18 prevents the lubricating oil in the transmission case 6 from escaping from the aforementioned space to the outside, and the sealing member 46 prevents the lubricating oil from entering the interior of the electric motors 11 and 12.

[0061] (Configuration of the transmission system to the rear wheels in the transmission case) - 1 As shown in Figures 8 and 9, the travel transmission shaft 41, the PTO transmission shaft 42, the front wheel transmission shaft 31, and the mid-PTO shaft 29 are arranged in a vertical line along an imaginary line L3 set in the vertical direction in the center of the left and right of the transmission case 6.

[0062] Of the traveling transmission shaft 41, the PTO transmission shaft 42, the front wheel transmission shaft 31, and the mid-PTO shaft 29, the traveling transmission shaft 41 is provided at the highest position. The PTO transmission shaft 42 is provided below the traveling transmission shaft 41, the front wheel transmission shaft 31 is provided below the PTO transmission shaft 42, and the mid-PTO shaft 29 is provided below the front wheel transmission shaft 31.

[0063] Assume that an imaginary line L1 extends rearward from the output shaft 11b (input shaft 25) of the electric motor 11, and an imaginary line L2 extends rearward from the output shaft 12b (input shaft 26) of the electric motor 12. The travel transmission shaft 41, the PTO transmission shaft 42, the front wheel transmission shaft 31, and the mid PTO shaft 29 are located between the imaginary lines L1 and L2 in a plan view (rear view). In this case, the imaginary line L1 is the first imaginary line, and the imaginary line L2 is the second imaginary line.

[0064] The traveling relay shaft 43 is provided at a height between the traveling transmission shaft 41 and the PTO transmission shaft 42, and is provided between the imaginary line L1 and the imaginary line L2 in a plan view (rear view), and is provided between the imaginary line L1 and the traveling transmission shaft 41 in a plan view (rear view).

[0065] 8, 9, and 11, the transmission gear 39a of the traveling clutch 39 is engaged with the transmission gear 43a connected to the traveling relay shaft 43. The power of the traveling clutch 39 is transmitted toward the left-right center of the transmission case 6 by the transmission gear 39a of the traveling clutch 39 and the transmission gear 43a of the traveling relay shaft 43, and then transmitted to the traveling relay shaft 43. In this case, the transmission gear 39a of the traveling clutch 39 and the transmission gear 43a of the traveling relay shaft 43 form a first transmission mechanism.

[0066] A speed change device 44 is provided across the traveling relay shaft 43 and the traveling transmission shaft 41. In the speed change device 44, a high-speed gear 47 rotatably attached to the traveling relay shaft 43 meshes with a transmission gear 41 a connected to the traveling transmission shaft 41, and a low-speed gear 48 rotatably attached to the traveling relay shaft 43 meshes with a transmission gear 41 b connected to the traveling transmission shaft 41. A shift member 49 is attached to the traveling relay shaft 43 by a spline structure so as to be rotatable and slidable integrally therewith.

[0067] In the transmission 44, when the shift member 49 is engaged with the high-speed gear 47, the power of the traveling relay shaft 43 is transmitted at high speed to the traveling transmission shaft 41 via the high-speed gear 47 and the transmission gear 41 a of the traveling transmission shaft 41. When the shift member 49 is engaged with the low-speed gear 48, the power of the traveling relay shaft 43 is transmitted at low speed to the traveling transmission shaft 41 via the low-speed gear 48 and the transmission gear 41 b of the traveling transmission shaft 41.

[0068] As a result, the power of the output shaft 11b of the electric motor 11 is transmitted to the rear wheels 2 via the input shaft 25, the traveling clutch 39, the traveling relay shaft 43, the speed change device 44, the traveling transmission shaft 41, and the rear wheel differential device 45. Based on the operation of the speed change pedal 35 (see FIG. 1), the electric motor 11 operates in forward and reverse rotation at a stepless speed, and the electric tractor moves forward (forward rotation of the electric motor 11) and backward (reverse rotation of the electric motor 11).

[0069] (Brake-Related Configuration) As shown in Fig. 8, a right brake 50 capable of braking the right rear wheel 2 and left and right brakes 50 capable of braking the left rear wheel 2 are provided in the third portion 6c of the transmission case 6. The right brake 50 and the right brake pedal 36 (see Fig. 1) are connected via a right linkage mechanism (not shown). The left brake 50 and the left brake pedal 36 (see Fig. 1) are connected via a left linkage mechanism (not shown).

[0070] When the operator of the driving section 8 steers the front wheels 1 to the right (left) using the steering handle 33, he or she depresses the right (left) brake pedal 36 to brake the right (left) rear wheels 2, thereby making a sharp turn to the right (left).

[0071] When the electric tractor is stopped from a traveling state, for example, if the operator of the driving unit 8 depresses the right and left brake pedals 36 to brake the right and left rear wheels 2, the depression of the right and left brake pedals 36 is detected and the traveling clutch 39 is disengaged. During maintenance work, for example, the operator can start and stop the electric motor 11 while keeping the traveling clutch 39 disengaged.

[0072] 2, 8, and 10, a pipe member 30 is connected in the front-to-rear direction between the rear portion 15 of the housing frame 5 and the front axle case 7. A front wheel transmission shaft 31 extends forward from the inside of the third portion 6c of the transmission case 6, passes through the inside of the pipe member 30, and is connected to a front wheel differential device (not shown) of the front axle case 7.

[0073] 5 and 7, the storage frame 5 has a recess 14a that is open downward and faces upward, in the left-right center of the lower part of the front part 14. As shown in Figures 5, 6, 8 and 10, in the storage frame 5, the pipe member 30 and the front wheel transmission shaft 31 are provided in the recess 14a in the front part 14 of the storage frame 5, and the front wheel transmission shaft 31 is provided in the opening 15b in the rear part 15 of the storage frame 5. The pipe member 30 and the front wheel transmission shaft 31 are provided at the position of the imaginary line L4 in a plan view.

[0074] A bearing portion 32 having a bearing is provided in the opening 15b of the rear portion 15 of the storage frame 5. The front wheel transmission shaft 31 passes through the bearing portion 32 and 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 of the pipe member 30 is attached to the bearing portion 32. In this case, the bearing portion 32 serves as the front wheel transmission bearing portion.

[0075] A seal member 51 is provided in the bearing portion 32. As a result, even if lubricating oil in the transmission case 6 attempts to enter the inside of the pipe member 30 through the opening 15b of the rear portion 15 of the housing frame 5 and the bearing portion 32, it is blocked by the seal member 51. Even if the lubricating oil in the transmission case 6 does enter the inside of the pipe member 30, the lubricating oil in the transmission case 6 cannot escape from the inside of the pipe member 30 to the outside. In this case, the seal member 51 serves as a front wheel transmission seal member.

[0076] The pipe member 30 and the front wheel transmission shaft 31 are arranged 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 arranged in the left-right center of the storage frame 5, and are arranged directly below the frame 17 of the storage frame 5 (see Figures 3 to 7).

[0077] 5 and 6, 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.

[0078] (Configuration of the transmission system to the front wheels in the transmission case)-2 As shown in Figures 8, 9, 11, and 12, the traveling relay gear 52 is rotatably attached to the PTO transmission shaft 42, and the transmission gear 41c connected to the traveling transmission shaft 41 is engaged with the traveling relay gear 52.

[0079] The front wheel transmission shaft 31 is attached to the switching gear 53 so that the switching gear 53 can rotate and slide integrally with the front wheel transmission shaft 31. The switching gear 53 can be slid between an engagement position where it engages with the traveling relay gear 52 and a spaced position where it is separated from the traveling relay gear 52.

[0080] When the switching gear 53 is operated to an engagement position where it engages with the traveling relay gear 52, the power of the traveling transmission shaft 41 is transmitted to the front wheel transmission shaft 31 via the transmission gear 41c of the traveling transmission shaft 41, the traveling relay gear 52, and the switching gear 53, and then transmitted from the front wheel transmission shaft 31 to the front wheels 1. This state is a four-wheel drive state in which the front wheels 1 and rear wheels 2 are driven.

[0081] When the switching gear 53 is operated to a separate position away from the traveling relay gear 52, the power of the traveling transmission shaft 41 is not transmitted to the front wheel transmission shaft 31, and the front wheels 1 are not driven. This state is a rear two-wheel drive state in which the rear wheels 2 are driven.

[0082] In this case, the input shaft 25, running clutch 39, running relay shaft 43, transmission 44, running transmission shaft 41 and rear wheel differential device 45, running relay gear 52, switching gear 53, front wheel transmission shaft 31, etc. constitute the transmission mechanism of the running system to the front wheels 1 and rear wheels 2.

[0083] (Configuration of the transmission system to the PTO shaft and mid-PTO shaft in the transmission case) - 1 As shown in Figures 8, 9 and 12, transmission gears 54, 55 and 56 are provided at a height between the traveling transmission shaft 41 and the input shaft 26, are provided between imaginary lines L1 and L2 in a plan view (rear view), and are provided between imaginary line L2 and the PTO transmission shaft 42 (traveling transmission shaft 41) in a plan view (rear view).

[0084] The transmission gear 40a of the PTO clutch 40 is engaged with the transmission gear 54. The transmission gears 55 and 56 are connected to each other so as to be rotatable as a single unit, and the transmission gears 55 and 54 are engaged with each other, and the transmission gear 56 is engaged with the transmission gear 42a connected to the PTO transmission shaft 42.

[0085] The PTO relay gear 57 and the PTO relay gear 58 are connected to each other so as to be rotatable as a unit, and the PTO relay gears 57, 58 are rotatably attached to the front wheel transmission shaft 31. The transmission gear 42b connected to the PTO transmission shaft 42 and the PTO relay gear 57 are in mesh with each other.

[0086] A transmission gear 59 is rotatably attached to the mid-PTO shaft 29, and the PTO relay gear 58 meshes with the transmission gear 59. A shift member 60 is attached to the mid-PTO shaft 29 by a spline structure so as to be rotatable and slidable integrally therewith.

[0087] 8, 9, and 12, the power of the PTO clutch 40 is transmitted toward the left-right center of the transmission case 6 by the transmission gear 40a of the PTO clutch 40 and transmission gears 54, 55, and 56, then to the PTO transmission shaft 42, and from the PTO transmission shaft 42 to the PTO shaft 28. In this case, the transmission gear 40a of the PTO clutch 40, the transmission gear 42a of the PTO transmission shaft 42, and the transmission gears 54, 55, and 56 form a second transmission mechanism.

[0088] When the shift member 60 is engaged with the transmission gear 59 , the power of the PTO transmission shaft 42 is transmitted to the mid-PTO shaft 29 via the transmission gear 42 b of the PTO transmission shaft 42 , the PTO relay gears 57 and 58 , the transmission gear 59 , and the shift member 60 .

[0089] As a result, the PTO clutch 40 is operated to the transmission state and the disengagement state, thereby operating and stopping the PTO shaft 28 and the mid-PTO shaft 29. When the shift member 60 is operated to move away from the transmission gear 59 while the PTO clutch 40 is operated to the transmission state, the mid-PTO shaft 29 stops while the PTO shaft 28 remains in the operating state.

[0090] 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.

[0091] In this case, the PTO clutch 40 , PTO transmission shaft 42 , PTO relay gears 57 , 58 , transmission gear 59 , shift member 60 , etc. constitute a PTO system transmission mechanism to the PTO shaft 28 and mid-PTO shaft 29 .

[0092] 1, 2, and 8, the right portion of the first portion 6a of the transmission case 6 is positioned laterally outward to the right of the right portion of the second portion 6b of the transmission case 6. As a result, the width W1 of the first portion 6a of the transmission case 6 in the left-right direction is greater than the width W2 of the second portion 6b of the transmission case 6 in the left-right direction.

[0093] The hydraulic pump 61 is attached facing rearward to the right portion of the first portion 6a of the transmission case 6. As a result, the hydraulic pump 61 is provided on the right side of the imaginary line L4, which is the same side as the electric motor 12, in a plan view. The hydraulic pump 61 is provided laterally outward from the right portion of the second portion 6b of the transmission case 6 (the same side as the electric motor 12), and is provided rearward of the right portion of the rear portion 15 of the accommodation frame 5 (the same side as the electric motor 12).

[0094] 8 and 9, a transmission gear 62 and a transmission gear 63 are provided in the right portion inside the first portion 6a of the transmission case 6. The transmission gear 26a connected to the input shaft 26 meshes with the transmission gear 62, the transmission gear 62 meshes with the transmission gear 63, and the transmission gear 63 meshes with the input gear 61a of the hydraulic pump 61.

[0095] The power of the electric motor 12 is transmitted to the hydraulic pump 61 via the transmission gear 26a of the input shaft 26 and transmission gears 62 and 63, thereby driving the hydraulic pump 61. Because the PTO clutch 40 is provided downstream of the input shaft 26, the hydraulic pump 61 is driven by the electric motor 12 even when the PTO clutch 40 is disengaged.

[0096] (Configuration of the Filter) As shown in FIGS. 2 and 8, a lubricating oil outlet (not shown) is opened in the left portion of the second portion 6b of the transmission case 6, and the filter 64 is connected to the outlet.

[0097] The filter 64 is provided laterally outward from the left portion (opposite the electric motor 12) of the second part 6b of the transmission case 6, and is provided rearward from the left portion (opposite the electric motor 12) of the rear part 15 of the accommodating frame 5.

[0098] As shown in Figures 1, 2 and 8, the oil supply passage 74 is connected between the hydraulic pump 61 and the filter 64, and the oil supply passage 74 is provided above the second portion 6b of the transmission case 6 along the left-right direction.

[0099] Lubricating oil in the transmission case 6 passes through a filter 64 and then through a supply oil passage 74, and is supplied as hydraulic oil to the hydraulic pump 61. The hydraulic oil from the hydraulic pump 61 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 operates using the supplied hydraulic oil.

[0100] 1 and 2, an electric tractor may be equipped with a front loader device 65, which is a work device. 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.

[0101] When the front loader device 65 is installed, the lower part of the right base 66 of the front loader device 65 is connected to the outer lateral surface of the right mounting portion 23 of the storage frame 5, and the lower part of the left base 66 is connected to the outer lateral surface of the left mounting portion 23 of the storage frame 5.

[0102] When the base 66 of the front loader device 65 is connected to the mounting portion 23 of the storage frame 5, the front end portion of the right (left) front and rear frame 73 is connected to the lateral outer surface portion of the right (left) base 66 of the front loader device 65, and the rear end portion of the right (left) front and rear frame 73 is connected to the right (left) rear axle case 6d of the transmission case 6.

[0103] As a result, the base 66 of the front loader device 65 is sandwiched between the mounting portion 23 and the front end of the front and rear frames 73, and the mounting portion 23, the front end of the front and rear frames 73 and the base 66 of the front loader device 65 are fastened together.

[0104] The right front-rear frame 73 is provided laterally outward to the right of the right inverter 24 and the transmission case 6, and is provided laterally outward to the right of the hydraulic pump 61. The left front-rear frame 73 is provided laterally outward to the left of the left inverter 24 and the transmission case 6, and is provided laterally outward to the left of the filter 64.

[0105] 1 and 2, a control valve unit 71 provided with a plurality of electromagnetically operated control valves is attached to the front of the right front / rear frame 73, and a cover 75 covering the control valve unit 71 is attached to the right front / rear frame 73. An oil passage 76 is connected between the hydraulic pump 61 and the control valve unit 71, and hydraulic oil from the hydraulic pump 61 is supplied to the control valve unit 71. In this case, the control valve unit 71 serves as a control valve.

[0106] Right and left fenders 77 are provided on the right and left parts of the driver's section 8, above the right and left rear wheels 2. An operating lever 72 is provided at the front of the upper part of the right fender 77.

[0107] As a result, the operating lever 72 is provided on the right side of the left-right center of the driving unit 8 in a plan view, and is provided on the right side (the same side as the electric motor 12) of the left-right center of the driving unit 8 in a plan view. The left-right center of the driving unit 8 and the virtual line L4 are in approximately the same position in a plan view.

[0108] A position sensor (not shown) that detects the operating position of the operating lever 72 is provided on the right fender 77, and the control valve of the control valve unit 71 is operated based on the operation of the operating lever 72. In this case, the operating lever 72 is a manual operating tool.

[0109] The operator in the driver's seat 34 operates the operating lever 72 with his right hand to operate the control valve of the control valve unit 71. As a result, hydraulic oil from the hydraulic pump 61 is supplied to and discharged from the boom cylinder 69 and bucket cylinder 70 of the front loader device 65 via the control valve unit 71, and the boom 67 and bucket 68 of the front loader device 65 are operated.

[0110] (First Alternative Embodiment of the Invention) The storage frame 5 may be eliminated, and only a flat plate-shaped connecting portion may be provided.

[0111] According to this configuration, the coupling portion may be configured to be coupled to the lower part of the floor 38. The front frame 4 may be configured to extend rearward beneath the floor 38 and be coupled to the transmission case 6, with the coupling portion being coupled to the front frame 4. According to this configuration, the electric motors 11, 12 are coupled to the front portion of the coupling portion, and the transmission case 6 is coupled to the rear portion of the coupling portion. A base 66 of the front loader device 65 may be configured to be coupled to the front frame 4.

[0112] (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.

[0113] Third 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 61 .

[0114] According to this configuration, the hydraulic pump 61 may be configured to be driven by an electric motor (not shown) separate from the electric motors 11, 12. The hydraulic pump 61 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 the operating lever 72 may be attached to the left fender 77.

[0115] (Fourth 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.

[0116] When a work implement is installed, the hydraulic oil of the hydraulic pump 61 is supplied to hydraulic equipment such as a power steering device (not shown) installed on the electric tractor and the work implement. When a work implement is not installed, the hydraulic oil of the hydraulic pump 61 is supplied to hydraulic equipment such as a power steering device installed on the electric tractor.

[0117] Fifth 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 61 .

[0118] According to this configuration, the hydraulic pump 61 may be configured to be driven by an electric motor (not shown) separate from the electric motors 11, 12. The hydraulic pump 61 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 the operating lever 72 may be attached to the left fender 77.

[0119] (Sixth Alternative Embodiment of the Invention) The front wheel transmission shaft 31 may be provided above the traveling transmission shaft 41. Between the imaginary lines L1 and L2 in a plan view, the front wheel transmission shaft 31 may be provided between the traveling transmission shaft 41 and the imaginary line L1 in a plan view, or may be provided between the traveling transmission shaft 41 and the imaginary line L2 in a plan view.

[0120] Seventh 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.

[0121] According to this configuration, the traveling clutch 39 (imaginary line L1), traveling relay shaft 43, and speed change device 44 are provided on the right side of the traveling transmission shaft 41 and the PTO transmission shaft 42 in a plan view. The PTO clutch 40 (imaginary line L2) and transmission gears 54, 55, 56 are provided on the left side of the traveling transmission shaft 41 and the PTO transmission shaft 42 in a plan view.

[0122] (Eighth alternative embodiment of the invention) 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 located slightly rearward of the front ends of the electric motors 11 and 12.

[0123] (Ninth Alternative Embodiment of the Invention) One electric motor 11 may be housed in the housing frame 5. With this configuration, the left-right width W4 of the housing frame 5 and the left-right width W1 of the first portion 6a of the transmission case 6 may be substantially the same. In this case, the electric motor 12 may be attached to a location separate from the housing frame 5.

[0124] (Tenth 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, the electric motor 12 may be attached to a part separate from the housing frame 5.

[0125] Eleventh Alternative Embodiment One electric motor 12 may be housed in the housing frame 5. With this configuration, the left-right width W4 of the housing frame 5 and the left-right width W1 of the first portion 6a of the transmission case 6 may be substantially the same. In this case, the electric motor 11 may be attached to a location separate from the housing frame 5.

[0126] (Twelfth 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, the electric motor 11 may be attached to a part other than the housing frame 5.

[0127] (Thirteenth Alternative Embodiment) 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.

[0128] (Fourteenth alternative embodiment of the invention) The output shafts 11b, 12b of the electric motors 11, 12 may be configured to extend rearward, pass through an opening 15a in the rear portion 15 of the housing frame 5, enter the interior of the transmission case 6, and be connected to the input shaft (not shown) of the driving clutch 39 and the input shaft (not shown) of the PTO clutch 40.

[0129] According to this configuration, the output shafts 11b, 12b of the electric motors 11, 12 pass through the bearing portion 27 and are supported by the bearing portion 27. The input shaft of the traveling clutch 39 and the input shaft of the PTO clutch 40 serve as input shafts of the transmission mechanism.

[0130] Fifteenth Alternative Embodiment of the Invention When the front loader device 65 is not installed, the front and rear frames 73 may be connected across the mounting portion 23 of the storage frame 5 and the rear axle case 6 d of the transmission case 6 .

[0131] (16th Alternative Embodiment) The vehicle may be configured as a rear two-wheel drive vehicle instead of a four-wheel drive vehicle. In this configuration, the pipe member 30, the front wheel transmission shaft 31, the bearing 32, the seal member 51, the opening 15b in the rear portion 15 of the storage frame 5, and the recess 14a in the front portion 14 are eliminated.

[0132] (Seventeenth 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.

[0133] 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.

[0134] (Correspondence to Claims) -1 With the above configuration, the vehicle is provided with electric motors 11, 12 that generate power for traveling or power and hydraulic pressure to operate the attached working device (front loader device 65). A transmission case 6 is provided that is located rearward of the electric motors 11, 12, has a transmission mechanism installed therein, and stores lubricating oil therein. A flat-plate-shaped connecting portion (rear portion 15) is provided between the electric motors 11, 12 and the transmission case 6, extending in the vertical and horizontal directions.

[0135] The rear portions of the electric motors 11, 12 are connected to the front portion of the connecting portion (rear portion 15), and the front portion (first portion 6a and second portion 6b) of the transmission case 6 is connected to the rear portion of the connecting portion (rear portion 15). An opening 15a is provided in the connecting portion (rear portion 15) for connecting the output shafts 11b, 12b of the electric motors 11, 12 or the input shafts 25, 26 of the transmission mechanism through the opening 15a. A seal member 37 is provided in the opening 15a to prevent lubricating oil in the transmission case 6 from flowing toward the electric motors 11, 12 through the opening 15a.

[0136] (Correspondence to Claims)-2 With the above configuration, the front portion (first portion 6a and second portion 6b) of the transmission case 6 is open toward the front. By connecting the front portion (first portion 6a and second portion 6b) of the transmission case 6 to the rear surface of the connecting portion (rear portion 15), the front portion (first portion 6a and second portion 6b) of the transmission case 6 is closed by the connecting portion (rear portion 15).

[0137] A bearing portion 27 is provided in the opening 15a. The input shafts 25, 26 pass through the opening 15a and are supported by the bearing portion 27, protrude from the connecting portion (rear portion 15) toward the electric motors 11, 12, and are connected to the output shafts 11b, 12b. A seal member 37 is provided in the bearing portion 27. A storage frame 5 that houses the electric motors 11, 12 is provided. The connecting portion (rear portion 15) is the rear portion 15 of the storage frame 5.

[0138] (Correspondence to Claims)-3 With the above configuration, the vehicle is provided with a front wheel 1 for running, which is provided forward of the electric motors 11, 12, and a rear running device (rear wheel 2) attached to the transmission case 6. The vehicle is provided with a front wheel transmission opening (opening 15b) provided in the connecting portion (rear portion 15), and a front wheel transmission shaft 31 that extends from the transmission case 6 through the front wheel transmission opening (opening 15b) toward the front wheel 1.

[0139] The power of the electric motor 11 is transmitted from the transmission mechanism to the running device (rear wheels 2) and the front wheel transmission shaft 31, and then from the front wheel transmission shaft 31 to the front wheels 1. A front wheel transmission seal member (seal member 51) is provided in the front wheel transmission opening (opening 15b) to prevent lubricating oil in the transmission case 6 from flowing toward the electric motors 11, 12 through the front wheel transmission opening (opening 15b).

[0140] A front wheel transmission bearing (bearing 32) is provided in the front wheel transmission opening (opening 15b). A front wheel transmission shaft 31 passes through the front wheel transmission opening (opening 15b) and is supported by the front wheel transmission bearing (bearing 32). A front wheel transmission seal member (seal member 51) is provided in the front wheel transmission bearing (bearing 32).

[0141] The present invention can be applied to an electric tractor.

[0142] DESCRIPTION OF SYMBOLS 1 Front wheel 2 Rear wheel (rear traveling device) 5 Storage frame 6 Transmission case 6a First part of transmission case (front part of transmission case) 6b Second part of transmission case (front part of transmission case) 11 Electric motor 11a Flange part of electric motor (rear part of electric motor) 11b Output shaft of electric motor 12 Electric motor 12a Flange part of electric motor (rear part of electric motor) 12b Output shaft of electric motor 15 Rear part of storage frame (connecting part) 15a Opening part at rear of storage frame (opening) 15b Opening part at rear of storage frame (front wheel transmission opening) 25 Input shaft 26 Input shaft 27 Bearing part 31 Front wheel transmission shaft 32 Bearing part (front wheel transmission bearing part) 37 Seal member 51 Seal member (front wheel transmission seal member) 65 Front loader device (working device)

Claims

1. An electric motor that generates power and hydraulics to operate the drive or the equipped work equipment, A transmission case is provided behind the aforementioned electric motor, has a transmission mechanism inside, and stores lubricating oil inside. A flat plate-shaped connecting portion is provided between the electric motor and the transmission case, oriented in the vertical and horizontal directions. The rear of the electric motor is connected to the front of the connecting part, and the front of the transmission case is connected to the rear of the connecting part. The connecting portion is provided with an opening for connecting the output shaft and the input shaft through the output shaft of the electric motor or the input shaft of the transmission mechanism, An electric tractor is provided with a sealing member in the opening, which prevents the lubricating oil of the transmission case from flowing through the opening toward the electric motor.

2. The front of the aforementioned transmission case is open toward the front, The electric tractor according to claim 1, wherein the front part of the transmission case is connected to the rear part of the connecting part, thereby closing the front part of the transmission case by the connecting part.

3. The aforementioned opening is provided with a bearing portion, The electric tractor according to claim 2, wherein the input shaft is supported by the bearing portion through the opening, protrudes from the connecting portion toward the electric motor and is connected to the output shaft.

4. The electric tractor according to claim 3, wherein the sealing member is provided in the bearing portion.

5. The electric motor is housed in a housing frame, The electric tractor according to claim 1, wherein the connecting portion is the rear of the housing frame.

6. A front wheel for driving is provided in front of the aforementioned electric motor, The running gear after being attached to the aforementioned transmission case, The front wheel transmission opening provided in the aforementioned connecting portion, The transmission case is provided with a front wheel transmission shaft that extends from the transmission case through the front wheel transmission opening toward the front wheel, The power of the electric motor is transmitted from the transmission mechanism to the running gear and the front wheel transmission shaft, and from the front wheel transmission shaft to the front wheel. The electric tractor according to claim 1, further comprising a front wheel transmission seal member provided in the front wheel transmission opening, which prevents the lubricating oil of the transmission case from flowing through the front wheel transmission opening toward the electric motor.

7. The front wheel transmission opening is provided with a front wheel transmission bearing, The electric tractor according to claim 6, wherein the front wheel transmission shaft is supported by the front wheel transmission bearing portion through the front wheel transmission opening.

8. The electric tractor according to claim 7, wherein the front wheel transmission seal member is provided in the front wheel transmission bearing.