Work Vehicle

Abstract

A work vehicle includes travel devices; a battery; a motor; an inverter configured to operate the motor; an operation section including a steering wheel configured to operate the travel devices, and an operator seat; a transmission case housing a transmission for travel; and a transmission shaft, wherein the motor is between a front travel device and a rear travel device in a side view and below the steering wheel, and the motor, the transmission shaft, the transmission, and the travel devices are configured such that motive power from the motor is transmitted to the transmission via the transmission shaft and transmitted from the transmission to the travel devices.

Claims

1. A work vehicle comprising: travel devices comprising a front travel device and a rear travel device; a battery; a motor; an inverter configured to operate the motor; an operation section comprising: a steering wheel configured to operate the travel devices, and an operator seat; a transmission case housing a transmission for travel; and a transmission shaft, wherein the motor is between the front travel device and the rear travel device in a side view and below the steering wheel, and wherein the motor, the transmission shaft, the transmission, and the travel devices are configured such that motive power from the motor is transmitted to the transmission via the transmission shaft and transmitted from the transmission to the travel devices.

2. The work vehicle according to claim 1, further comprising: a left body frame and a right body frame extending in a front-back direction below the operation section, and wherein the motor is between the left body frame and the right body frame in a plan view.

3. A work vehicle comprising: at least one travel device comprising a front travel device; a battery; a motor; an inverter configured to operate the motor; an operation section comprising an operator seat; a transmission case housing a transmission for travel; and a transmission shaft, wherein the motor is above the front travel device or forward of the front travel device in a side view, and wherein the motor, the transmission shaft, the transmission, and the travel device are configured such that motive power from the motor is transmitted to the transmission via the transmission shaft and transmitted from the transmission to the travel device.

4. A work vehicle comprising: a travel device; a battery; a motor; an inverter configured to operate the motor; an operation section comprising an operator seat; and a transmission case housing a transmission for travel, wherein the transmission case is below the operator seat, wherein the motor is between the operator seat and the transmission case in a side view, and wherein the motor, the transmission, and the travel device are configured such that motive power from the motor is transmitted to the transmission and transmitted from the transmission to the travel device.

5. The work vehicle according to claim 1, further comprising: a work device; a link mechanism disposed on the transmission case, configured to be raised and lowered, and joined to the work device; a hydraulic cylinder disposed on the transmission case and configured to raise and lower the link mechanism; a hydraulic pump configured to supply hydraulic oil to the hydraulic cylinder; and a pump motor configured to drive the hydraulic pump, wherein the transmission case is below the operator seat, and wherein the pump motor is between the operator seat and the transmission case in a side view.

6. The work vehicle according to claim 1, further comprising: a work device; a link mechanism disposed on the transmission case, configured to be raised and lowered, and joined to the work device; and a work motor configured to supply motive power to the work device, and wherein the work motor is in the link mechanism.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] FIG. 1 is a left side view of a tractor.

[0034] FIG. 2 is a longitudinal front view of a region around an inverter and a motor.

[0035] FIG. 3 schematically shows a system for transmission from the motor to front and rear wheels.

[0036] FIG. 4 is a left side view of a tractor according to a second variation of implementation of the present invention.

[0037] FIG. 5 is a left side view of a tractor according to a third variation of implementation of the present invention.

[0038] FIG. 6 is a left side view of a tractor according to a fourth variation of implementation of the present invention.

[0039] FIG. 7 is a left side view of the tractor according to the fifth variation of implementation of the present invention.

[0040] FIG. 8 is a left side view of a tractor according to a seventh variation of implementation of the invention.

DESCRIPTION OF THE INVENTION

[0041] FIGS. 1 to 8 show electric tractors, each of which is an example of a work vehicle. In FIGS. 1 to 8, 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.

Overall Configuration of Tractor

[0042] As shown in FIG. 1, left and right front wheels 1 (each of which corresponds to a front travel device) and left and right rear wheels 2 (each of which corresponds to a rear travel device) support a body 3 of the tractor. A hood 4 is provided at a front portion of the body 3, and an operation section 5 is provided at a rear portion of the body 3. The operation section 5 includes a steering wheel 6 for steering the front wheels 1, an operator seat 7, a floor 8, and a ROPS frame 9.

[0043] The body 3 has left and right body frames 10, a transmission case 11, and so on. The transmission case 11 has a front case 12 and a rear case 13 that are joined to each other. The left and right body frames 10 are connected to the transmission case 11 and extend in the front-back direction below the operation section 5 (floor 8). The transmission case 11 is located below the operator seat 7 in the operation section 5.

[0044] A front axle case 14 is supported by front portions of the body frames 10, and supports the left and right front wheels 1. The transmission case 11 (rear case 13) supports the left and right rear wheels 2.

[0045] Atop link 15 (which corresponds to a link mechanism) and left and right lower links 16 (each of which corresponds to a link mechanism) are provided at a rear portion of the transmission case 11 (rear case 13) in such a manner as to be swingable in the up-down direction. The top link 15 and the lower links 16 can be joined to a work device (not shown), such as a rotary cultivator.

[0046] Left and right lift arms 17 are provided at the rear portion of the transmission case 11 (rear case 13), and a connecting rod 18 is connected to the lift arms 17 and the lower links 16. The top link 15 and the lower links 16 are raised and lowered and the work device is raised and lowered by swinging the lift arms 17 in the up-down direction.

Configuration of Front Portion of Body

[0047] As shown in FIGS. 1 and 2, a pillar frame 19 is provided on the body frames 10 between the front wheels 1 and the operation section 5 (rear wheels 2). The pillar frame 19 is constituted by a folded plate material and has a right section 19a, a left section 19b, an upper section 19c, and a rear section 19d.

[0048] The rear section 19d of the pillar frame 19 is flat and extends in the up-down direction and the left-right direction. The right section 19a of the pillar frame 19 is formed by bending forward a right portion of the rear section 19d of the pillar frame 19, and extends in the up-down direction and the front-back direction. The left section 19b of the pillar frame 19 is formed by bending forward a left portion of the rear section 19d of the pillar frame 19, and extends in the up-down direction and the front-back direction.

[0049] The upper section 19c of the pillar frame 19 is formed by bending forward an upper portion of the rear section 19d of the pillar frame 19, and extends in the left-right direction and the front-back direction. The upper section 19c of the pillar frame 19 extends between upper portions of the right section 19a and the left section 19b of the pillar frame 19.

[0050] As shown in FIG. 1, the hood 4 is supported such that the hood 4 is openable and closable about a fulcrum in the left-right direction of the upper section 19c of the pillar frame 19, and can be operated from a closed position shown in FIG. 1 to an open position above the closed position.

[0051] A power steering mechanism 20 is provided below a rear face portion of the rear section 19d of the pillar frame 19. A steering post 21 is attached to the power steering mechanism 20 and extends upward from the power steering mechanism 20. A steering wheel 6 is supported by an upper portion of the steering post 21, and a steering shaft 22 is connected to the steering wheel 6 and the power steering mechanism 20.

[0052] In response to the steering wheel 6 being rotated, the rotation of the steering wheel 6 is transmitted to the power steering mechanism 20 via the steering shaft 22, and the power steering mechanism 20 steers the front wheels 1 to the left and right.

[0053] With the above configuration, the steering wheel 6 for operating the front wheels 1 (front travel devices) is provided at a front portion of the operation section 5, and the steering shaft 22 for operating the front wheels 1 (front travel devices) extends downward from the steering wheel 6, as shown in FIG. 1.

Configuration Related to Battery and Inverter

[0054] A support platform 23 is attached to front upper portions of the left and right body frames 10, as shown in FIGS. 1 and 2. An inverter 24, which is provided on the support platform 23, has a rectangular case with a small dimension (dimension in the front-back direction) that houses various types of equipment.

[0055] The inverter 24 extends in the up-down direction in a side view and extends in the left-right direction in a plan view (front view), and is attached to a rear portion of the support platform 23 so as to be in contact with a front face portion of the rear section 19d of the pillar frame 19.

[0056] As shown in FIG. 1, the tractor has a battery 25, which is constituted by multiple pairs of stacks (not shown) of connected battery modules (not shown) that are housed in a rectangular-parallelepiped case. The battery 25 is attached to the support platform 23, and the hood 4 at the closed position covers the inverter 24 and the battery 25. Maintenance work for the inverter 24 and the battery 25 can be performed by opening the hood 4.

[0057] With the above configuration, the inverter 24 is provided between the right section 19a and the left section 19b of the pillar frame 19 in a front view and overlaps the right section 19a and the left section 19b of the pillar frame 19 in a side view, as shown in FIGS. 1 and 2. The inverter 24 is provided below the upper section 19c of the pillar frame 19 in a front view and overlaps the upper section 19c of the pillar frame 19 in a plan view.

[0058] The battery 25 is provided forward of the operation section 5, and the inverter 24 is provided between the battery 25 and the operation section 5 in a side view. The inverter 24 is provided between the battery 25 and the steering shaft 22 in a side view.

[0059] The pillar frame 19 is provided between the battery 25 and the operation section 5 in a side view, and the inverter 24 is provided between the battery 25 and the rear section 19d of the pillar frame 19 in a side view.

Configuration Related to Motor

[0060] Left and right mounting brackets 27 are joined to inner faces of the left and right body frames 10, and left and right portions of a motor 26 are joined to the left and right mounting brackets 27, as shown in FIGS. 1 and 2.

[0061] The inverter 24 converts DC power from the battery 25 to AC power and supplies the AC power to the motor 26 to operate the motor 26. Motive power from the motor 26 is supplied to the front wheels 1 and the rear wheels 2, as shown in FIG. 3.

[0062] With the above configuration, the motor 26 is provided between the front wheels 1 (front travel devices) and the rear wheels 2 (rear travel devices) and below the steering wheel 6 in a side view, as shown in FIGS. 1 and 2.

[0063] The left body frame 10 and the right body frame 10 are disposed in the front-back direction below the operation section 5 (floor 8), and the motor 26 is provided between the left body frame 10 and the right body frame 10 in a plan view (front view).

[0064] The motor 26 is provided below the pillar frame 19, the power steering mechanism 20, the inverter 24, and the rear portion of the battery 25 in a side view. The pillar frame 19, the power steering mechanism 20, and the inverter 24 are provided above the motor 26 in a side view.

Configuration of System for Transmission to Front Wheels and Rear Wheels

[0065] A hydrostatic continuously variable transmission 28 (which corresponds to a transmission for travel) is housed within the front case 12 of the transmission case 11, and motive power from the motor 26 is transmitted via a transmission shaft 29 to the continuously variable transmission 28, as shown in FIGS. 1 and 3. The continuously variable transmission 28 is capable of steplessly changing forward and backward and is operated by a gearshift pedal (not shown) on the floor 8 of the operation section 5.

[0066] An auxiliary transmission 30 (which corresponds to a transmission for travel), a rear wheel differential device 31, and a front wheel transmission 32 (which corresponds to a transmission for travel) are housed within the rear case 13 of the transmission case 11. Motive power subjected to speed change by the continuously variable transmission 28 is transmitted to the auxiliary transmission 30, and is then transmitted from the auxiliary transmission 30 to the rear wheels 2 via the rear wheel differential device 31.

[0067] Motive power diverted from between the auxiliary transmission 30 and the rear wheel differential device 31 is transmitted to the front wheel transmission 32, then transmitted from the front wheel transmission 32 via the transmission shaft 33 to the front wheel differential device 34 housed within the front axle case 14, and is transmitted from the front wheel differential device 34 to the front wheels 1.

[0068] The front wheel transmission 32 drives the front wheels 1 and the rear wheels 2 at the same speed while the front wheels 1 are operated within the range of left and right set angles from a straight-ahead position. The front wheel transmission 32 drives the front wheels 1 at a higher speed than the rear wheels 2 while the front wheels 1 are steered leftward or rightward beyond the left and right setting angles.

[0069] With the above configuration, the tractor has the transmission case 11 (front case 12 and rear case 13) that houses the continuously variable transmission 28 (transmission for travel), the auxiliary transmission 30 (transmission for travel), and the front wheel transmission 32 (transmission for travel), as shown in FIG. 3.

[0070] Motive power from the motor 26 is transmitted via the transmission shaft 29 to the continuously variable transmission 28 (transmission for travel), the auxiliary transmission 30 (transmission for travel), and the front wheel transmission 32 (transmission for travel), and is then transmitted from the continuously variable transmission 28 (transmission for travel), the auxiliary transmission 30 (transmission for travel), and the front wheel transmission 32 (transmission for travel) to the front wheels 1(travel devices) and the rear wheels 2 (travel devices).

Configuration of System for Transmission to Work Device Joined to Top Link and Lower Links

[0071] A PTO transmission 35 is housed within the rear case 13 of the transmission case 11, and a PTO shaft 36 is provided at a rear portion of the rear case 13 of the transmission case 11, as shown in FIGS. 1 and 3. A transmission shaft (not shown) is connected to the PTO shaft 36 and the work device in response to the work device being joined to the top link 15 and the lower links 16.

[0072] While motive power from the motor 26 is transmitted to the continuously variable transmission 28 via the transmission shaft 29, motive power from the transmission shaft 29 (motive power that is not subjected to speed change by the continuously variable transmission 28) is transmitted to the PTO transmission 35, and motive power subjected to speed change by the PTO transmission 35 is transmitted to the PTO shaft 36 and then transmitted from the PTO shaft 36 to the work device.

Configuration Related to Lifting Operation of Lift Arm

[0073] A single-acting hydraulic cylinder 37 is provided above the rear portion of the transmission case 11 (rear case 13), and the hydraulic cylinder 37 raises and lowers the lift arm 17, as shown in FIG. 3.

[0074] A hydraulic pump 38 and a control valve 39 are provided within the rear portion of the transmission case 11 (rear case 13). Lubricating oil that serves as hydraulic oil and stored in the transmission case 11 (rear case 13) is supplied to the hydraulic pump 38, and is then supplied from the hydraulic pump 38 to the control valve 39.

[0075] A pump motor 40 is provided above the rear portion of the transmission case 11 (rear case 13) and drives the hydraulic pump 38. The inverter 24 converts DC power from the battery 25 to AC power and supplies the AC power to the pump motor 40 to operate the pump motor 40.

[0076] Operations to supply and discharge the hydraulic oil to and from the hydraulic cylinder 37 are performed from the control valve 39, and the hydraulic cylinder 37 raises and lowers the lift arm 17. The hydraulic oil discharged from the hydraulic cylinder 37 is returned from control valve 39 to the transmission case 11 (rear case 13).

[0077] With the above configuration, the hydraulic cylinder 37, which raises and lowers the top link 15 (link mechanism) and the lower links 16 (link mechanism) to which the work device is joined, and the hydraulic pump 38, which supplies the hydraulic oil to the hydraulic cylinder 37, are provided in the transmission case 11 (rear case 13), as shown in FIGS. 1 and 3.

[0078] The pump motor 40, which drives the hydraulic pump 38, is located between the operator seat 7 in the operation section 5 and the transmission case 11 (rear case 13) in a side view.

First Variation of Implementation of the Invention

[0079] In the configuration shown in FIGS. 1 and 2, the motor 26 may be joined to the support platform 23 and supported by the body 3. The motor 26 may be joined to the pillar frame 19 and supported by the body 3.

[0080] In the configuration shown in FIGS. 1 and 2, the inverter 24 may be joined to the pillar frame 19 and supported by the body 3. The inverter 24 may be provided between the operator seat 7 in the operation section 5 and the transmission case 11 (front case 12 and rear case 13) in a side view, as shown in FIG. 7, which will be described later.

Second Variation of Implementation of the Invention

[0081] If the battery 25 is provided forward of the operation section 5 as shown in FIG. 4, the inverter 24 may be provided forward of the battery 25.

[0082] According to the configuration shown in FIG. 4, the inverter 24 extends in the up-down direction in a side view and extends in the left-right direction in a plan view (front view), and is provided between a front portion of the hood 4 and a front portion of the battery 25.

Third Variation of Implementation of the Invention

[0083] The motor 26 may be provided above the front axle case 14 (front wheels 1 (front travel devices)) in a side view, as shown in FIG. 5.

[0084] According to the configuration shown in FIG. 5, the motor 26 is provided below the front portion of the battery 25, and the position of the motor 26 is slightly higher. Thus, another support platform 41 need only be provided to the support platform 23 such that the battery 25 is attached to the support platform 41 to make the position of the battery 25 slightly higher.

[0085] In the configuration shown in FIG. 5, the motor 26 may be joined to the support platform 41 and supported by the body 3. The inverter 24 may be provided forward of the battery 25, as shown in FIG. 4. The inverter 24 may be provided between the operator seat 7 in the operation section 5 and the transmission case 11 (front case 12 and rear case 13) in a side view, as shown in FIG. 7, which will be described later.

Fourth Variation of Implementation of the Invention

[0086] The motor 26 may be provided forward of the front axle case 14 (front wheels 1 (front travel devices)) in a side view, as shown in FIG. 6.

[0087] According to the configuration shown in FIG. 6, the motor 26 is located at a lower position. Thus, a transmission mechanism 42 of a gear transmission type need only be attached to a portion of an output shaft (not shown) of the motor 26 in such a manner as to extend upward from the motor 26. The transmission shaft 29 need only be connected to an output shaft (not shown) at an upper portion of the transmission mechanism 42 and the continuously variable transmission 28 (see FIG. 3) such that the transmission shaft 29 extends in the front-back direction above the front axle case 14.

[0088] Motive power from the output shaft of the motor 26 is transmitted to the transmission mechanism 42, then transmitted the output shaft at the upper portion of transmission mechanism 42 to the continuously variable transmission 28 (see FIG. 3) via the transmission shaft 29, and is transmitted to the front wheels 1 and the rear wheels 2.

[0089] In the configuration shown in FIG. 6, the motor 26 may be joined to the support platform 23 and supported by the body 3. The inverter 24 may be provided forward of the battery 25, as shown in FIG. 4. The inverter 24 may be provided between the operator seat 7 in the operation section 5 and the transmission case 11 (front case 12 and rear case 13) in a side view, as shown in FIG. 7, which will be described later.

Fifth Variation of Implementation of the Invention

[0090] As shown in FIG. 7, if the transmission case 11 (front case 12 and rear case 13) is provided below the operator seat 7 in the operation section 5, the motor 26 may be attached to the upper portion of the transmission case 11 (front case 12 and rear case 13) and provided between the operator seat 7 in the operation section 5 and the transmission case 11 (front case 12 and rear case 13) in a side view.

[0091] The inverter 24 may be provided between the operator seat 7 in the operation section 5 and the transmission case 11 (front case 12 and rear case 13) in a side view by attaching the inverter 24 to a support frame 43 that is provided in the operation section 5 to support the operator seat 7.

[0092] In the configuration shown in FIG. 7, the motor 26 need only be attached to the upper portion of the transmission case 11 (front case 12 and rear case 13) such that an output shaft (not shown) of the motor 26 faces forward, and a transmission mechanism 44 of a gear transmission type need only be attached to the output shaft of the motor 26 and a forward-facing input shaft (not shown) of the continuously variable transmission 28 (see FIG. 3).

[0093] Motive power from the output shaft of the motor 26 is transmitted to the transmission mechanism 44, then transmitted from an output shaft (not shown) at a lower portion of the transmission mechanism 44 to the continuously variable transmission 28 (see FIG. 3), and is transmitted to the front wheels 1 and the rear wheels 2.

[0094] In the configuration shown in FIG. 7, the inverter 24 is supported in a suspended manner by a lower portion of the support frame 43 and extends in the horizontal direction. The inverter 24 is disposed at a position upward of and away from the motor 26 and the pump motor 40, and is disposed at a position upward of and away from the upper portion of the transmission case 11 (front case 12 and rear case 13).

Sixth Variation of Implementation of the Invention

[0095] If the motor 26 is provided between the operator seat 7 in the operation section 5 and the transmission case 11 (front case 12 and rear case 13) in a side view, as shown in FIG. 7, the inverter 24 may be provided rearward of the battery 25, as shown in FIG. 1. The inverter 24 may be provided forward of the battery 25, as shown in FIG. 4.

Seventh Variation of Implementation of the Invention

[0096] A work motor 45 may be provided on the left and right lower links 16 (link mechanism), as shown in FIG. 8.

[0097] According to the configuration shown in FIG. 8, with the work device joined to the top link 15 and the lower links 16, a transmission shaft (not shown) is connected to the work motor 45 and the work device. The inverter 24 converts DC power from the battery 25 to AC power, which is supplied to the work motor 45 to operate the work motor 45, and motive power from the work motor 45 is transmitted to the work device.

[0098] In the configuration shown in FIG. 8, the PTO transmission 35 and the PTO shaft 36 shown in FIGS. 1 and 3 may be eliminated. The work motor 45 may be provided on the top link 15 (link mechanism).

Eighth Variation of Implementation of the Invention

[0099] The tractor may have a four-wheel steering structure in which the front wheels 1 and the rear wheels 2 are steered in the same and opposite phases by the steering wheel 6.

[0100] Crawler-type travel devices (not shown) may be provided instead of the front wheels 1 as the front travel devices. Crawler-type travel devices (not shown) may be provided instead of the rear wheels 2 as the rear travel devices. One crawler-type travel device (not shown) may be provided instead of the front wheels 1 and the rear wheels 2.

INDUSTRIAL APPLICABILITY

[0101] The present invention can be applied to not only electric tractors in which a motor drives a travel device, but also to hybrid tractors in which an engine and a motor drive a travel device, and can be applied to not only tractors but also construction work vehicles and agricultural work vehicles.