TW201919468A - Work vehicle - Google Patents

Abstract

The purpose of the present invention is to efficiently arrange a power steering device inside the engine compartment so as to ensure sufficient leg room for a user. The present invention comprises: an engine 6; a transmission case 7 to which the drive from the engine 6 is transmitted; a steering shaft 41 for transmitting the steering force of a steering wheel 15 to wheels; and a power steering device 61 for applying steering assisting force to the steering shaft 41. The power steering device 61 is configured as an electrically-operated device which applies the drive power of an electric motor 62 to the steering shaft 41 supported by the top of the transmission case 7, wherein the engine 6, steering shaft 41, and power steering device 61 are arranged inside the engine compartment and the electric motor 62 is disposed rearwardly of the engine 6 and forwardly of the steering shaft 41 in terms of the front-rear direction.

Description

   Work vehicle   

The present invention relates to a work vehicle including a steering shaft that transmits a steering force of a steering wheel to a wheel, and a power steering device that imparts a steering assist force to the steering shaft.

In the above-mentioned work vehicles, a power steering device is known to be an electric type including an electric motor, and a driving force of the electric motor is given to a steering shaft as a steering assist force (for example, refer to Patent Document 1).

In the work vehicle described in Patent Document 1, a steering wheel is connected to an upper portion of a steering shaft, and the steering shaft is provided in a backward leaning posture in which the steering shaft is positioned more forward as it goes downward. The power steering device is provided with an electric motor in a state in which a pinion gear is engaged with a driving gear provided at an intermediate portion of a steering shaft, and the electric motor is actuated to apply a driving force of the electric motor to the steering shaft as a steering assist force. In this way, a steering assist force by the electric motor is applied from a lateral side orthogonal to the axial center direction of the steering shaft, and the electric motor is disposed at a position on the rear side of the steering shaft in the front-rear direction.

In the work vehicle described above, a steering shaft is supported at an upper portion of the transmission, and a steering wheel is supported at an upper end portion of the steering shaft (for example, refer to Patent Document 2).

In the work vehicle described in this Patent Document 2, a power steering device is disposed at an intermediate portion of a steering shaft, and the steering shaft is divided into an upper shaft and a lower shaft by the power steering device. The upper shaft is supported in the upper steering column, the upper end of the upper steering column is connected to the steering wheel, and the lower end of the upper steering column is connected to the power steering device. The lower shaft is supported in the lower steering column, the upper end of the lower steering column is connected to the power steering device, and the lower end of the lower steering column is connected to the upper part of the transmission.

    [Prior technical literature]         [Patent Literature]    

[Patent Document 1] Japanese Patent Laid-Open No. 2007-37510

[Patent Document 2] Japanese Patent Laid-Open No. 2007-38725

In the above-mentioned work vehicles, since various devices such as an engine, a steering shaft, and a power steering device are arranged in a bonnet, it is required to efficiently arrange various devices in a limited space in the hood. However, in the above-mentioned Patent Document 1, since the electric motor is disposed on the rear side than the steering shaft, it has a shape in which the hood projects behind the steering shaft. Therefore, the hood protrudes to the feet of the user who operates the steering wheel, and it is impossible to ensure sufficient space under the feet of the user, which brings a sense of pressure on the user.

In view of this actual situation, the main object of the present invention is to provide a work vehicle in which a power steering device is efficiently disposed in a hood, which can ensure a sufficient space under a user's feet.

In the work vehicle described in Patent Document 1, since the power steering device includes an electric motor, heat and water vapor generated by the electric motor and the like may accumulate inside the power steering device. External heat or radiation. That is, since an electric motor or other components of a power steering device are usually housed in a box, heat and water vapor generated in the electric motor or the like are accumulated in the box. However, it is not described in Patent Document 1 that heat or water vapor inside the power steering device is radiated or released to the outside. When the inside of the power steering device becomes hot, If moisture such as dew condensation accumulates inside, it may adversely affect the electric motor.

Another object of the present invention is to provide a work vehicle capable of suppressing a complicated structure or an increase in the number of components and dissipating or releasing heat or water vapor inside the power steering device to the outside.

In the work vehicle described in Patent Document 2, the upper steering wheel column and the power steering device are connected in a state where they are directly abutted by the fastening of a nut. Thereby, when the user operates the steering wheel, when an external force acts on the steering wheel, the external force is directly transmitted to the power steering device through the upper steering wheel column. Therefore, a large external force is applied to the power steering device, which adversely affects the power steering device.

Recently, as a power steering device, there is a case where an electric type is used in which a driving amount of an electric motor is given to a steering shaft as a steering assist force. The electric power steering device includes precision parts such as an electric motor, and thus is particularly required to reduce an external force applied to the power steering device.

Another object of the present invention is to provide a work vehicle capable of reducing external force applied to a power steering device.

A first characteristic configuration of the present invention includes: an engine; a transmission that transmits driving force from the engine; a steering shaft that transmits the steering force of the steering wheel to the wheels; and a power steering device that imparts a steering assist force to the steering shaft. The power steering system is an electric type in which a driving force of an electric motor is given to the steering shaft. The steering shaft system is supported on an upper part of the transmission. The engine, the steering shaft, and the power steering are arranged in a hood. In the device, the electric motor is disposed on a rear side of the engine in a front-back direction and a front side of the steering shaft.

According to this configuration, since the electric motor is arranged in the front-rear direction further behind the engine and forward than the steering shaft, the space between the engine and the steering shaft can be effectively utilized to arrange the electric motor. Efficiently configure power steering. Thereby, it is possible to prevent the hood from forming a shape protruding toward the rear side from the steering shaft, and to secure a sufficient space under the feet of a user who operates the steering wheel.

A second characteristic configuration of the present invention is that a transmission having a transmission mechanism is provided in the hood, and the transmission mechanism is used to shift the output from the transmission in accordance with a shift operation, and the transmission is disposed in the hood. In the upper part of the transmission, the electric motor is disposed on an upper side than the transmission.

According to this configuration, the upper space of the transmission is effectively utilized in the hood, and not only the electric motor but also the transmission can be provided. Furthermore, the electric motor is arranged above the gearbox, and since the electric motor and the gearbox are arranged at different positions in the up-and-down direction, interference between the electric motor and the gearbox can be suppressed, and the electric motor and the gearbox can be efficiently arranged. Therefore, the space in the hood can be effectively utilized, and the engine, the steering shaft, the power steering device, and the transmission can be efficiently arranged.

A third characteristic configuration of the present invention is that the electric motor and the transmission are arranged on the same side in the left-right direction with respect to the steering shaft.

According to this configuration, since the space on one side in the left-right direction with respect to the steering shaft can be utilized to arrange the electric motor and the gearbox together, it is not necessary to secure the electric motor on the other side in the left-right direction with respect to the steering shaft. Configuration space for gearboxes, etc. Thereby, a space can be secured on the other side in the left-right direction with respect to the steering shaft, and the space can be utilized for space for performing maintenance work of an engine or the like or various other uses.

A fourth feature of the present invention is that it includes a flywheel cover that covers the flywheel of the engine from above, and the electric motor is disposed above a tangent line of the flywheel that passes through an outer peripheral portion of the flywheel and a lower end of the flywheel cover. side.

According to this configuration, since the flywheel cover covers the flywheel from the upper side, the flywheel cover can prevent muddy water and the like from being scattered toward the upper side. Since the electric motor is arranged above the tangent line of the flywheel that passes through the outer periphery of the flywheel and the lower end of the flywheel cover, the electric motor can be arranged at a position where the flywheel cover prevents the mud and water from scattering, which can prevent the Electric motors cause adverse effects.

A fifth characteristic structure of the present invention includes a support member configured to support the steering shaft and the power steering device. The support member is configured to support the steering shaft in a state where the steering shaft is located in a hollow space inside the steering shaft. The power steering device is supported in a state in which a hollow space inside the power steering device is communicated with the inside of the power steering device. The power steering device includes an external opening portion and opens the inside of the support member to the outside.

According to this configuration, since the support member supports the power steering device in a state where the hollow space inside it communicates with the inside of the power steering device, the heat and water vapor inside the power steering device can be made hollow inside the support member. Space radiates or emits. In addition, since an external opening portion is provided to open the inside of the support member to the outside, heat or heat released from the inside of the support member can be radiated or released to the outside through the external opening portion. In this way, the heat and water vapor inside the power steering device can be efficiently radiated or released to the outside while utilizing the hollow space inside the support member. In addition, since the supporting member is a member for supporting the steering shaft and the power steering device, it can be used as a supporting member in terms of a structure for radiating or releasing heat and water vapor inside the power steering device to the outside. . Therefore, it is possible to suppress the complication of the structure or increase in the number of components, and to release heat or heat from the inside of the power steering device to the outside. In addition, even if water or the like invades from the external open portion, the water may invade the inside of the support member, but for example, by disposing a power steering device or the like on the upper portion of the support member, water can be prevented from reaching the power steering device. Therefore, heat or water vapor inside the power steering device can be radiated or released to the outside, and water or the like can be appropriately prevented from entering the power steering device.

A sixth characteristic configuration of the present invention is that the transmission case supports the lower end portion of the support member and transmits driving force to the wheels, and includes a communication connection portion in a state where the inside of the transmission case and the inside of the support member are communicated. The aforementioned transmission is connected to the aforementioned supporting member.

According to this configuration, since the communication connecting portion connects the transmission and the supporting member in a state where the inside of the transmission and the inside of the supporting member are communicated, the air inside the transmission can pass through the connecting connecting portion to the inside of the supporting member. supply. Then, the air inside the gearbox supplied to the inside of the support member can be exhausted to the outside through the external opening portion. This prevents the inside of the transmission from becoming high pressure. In addition, as a structure for exhausting the air inside the gearbox to the outside, not only the support member but also the external open portion can be used to simplify the structure and release the heat and water vapor inside the power steering device to the outside. Or let out, and exhaust the air inside the gearbox to the outside.

A seventh characteristic configuration of the present invention is that the connection portion of the communication connection portion to the support member is disposed above the connection portion of the external opening portion to the support member.

When water or the like intrudes from the external open portion, the water may enter the inside of the support member. Therefore, according to this configuration, by arranging the connection portion of the communication connection portion to the support member on the upper side than the connection portion of the external open portion to the support member, it is possible to prevent water or the like entering the support member from entering through the connection connection portion. Gearbox interior. Thereby, with a simple structure in which the connection portion of the communication connection portion and the external open portion is adjusted in the vertical direction, it is possible to appropriately handle the intrusion of water and the like from the external open portion.

An eighth characteristic configuration of the present invention is that the connection portion of the communication connection portion to the support member and the connection portion of the external opening portion to the support member are sandwiched between the center portion of the support member in a side view and The front and rear directions are separated.

According to this configuration, since the connection portion of the communication connection portion to the support member and the connection portion of the external opening portion to the support member are arranged in a state of being sandwiched between the center portion of the support member in the side view and separated in the front-rear direction, the use In the length of the support member in the front-rear direction, the connection portion of the communication connection portion can be disposed closer to the transmission side, and the connection portion of the external opening portion can be disposed closer to the outside. This makes it possible to shorten the length of the communication connection portion and the external open portion as much as possible, and to simplify the configuration.

A ninth characteristic configuration of the present invention is that the power steering device is disposed at a midway portion of the steering shaft, and includes a lower support member that extends in a state that surrounds a lower portion of the steering shaft than the power steering device. In the axial center direction of the steering shaft; and an upper support member connected to the steering wheel through an intermediate member, and extending to the axial center of the steering shaft in a state surrounding the steering shaft above the power steering device Direction, the steering shaft and the lower support member are supported on the upper part of the transmission, the power steering device is supported on the upper part of the lower support member, and the upper support member is on the upper part of the lower support member. , Is supported at a position deviating from the support position of the power steering device.

According to this configuration, the steering shaft can be provided in a state in which the lower side support member and the upper side support member surround the steering shaft, and as the member for supporting the power steering device, the lower side support member can be used. The upper support member is located on the upper part of the lower support member and is supported at a position deviating from the support position of the power steering device. Therefore, it is possible to prevent the force transmitted by the upper support member from being directly applied to the power steering device. Supports both power steering and upper support members. Therefore, when a user operates the steering wheel, even if an external force acts on the steering wheel, the external force is transmitted to the upper support member via the intermediate member, and the external force transmitted to the upper support member can be prevented from being directly transmitted to the power steering device. From the above, it can be known that both the power steering device and the upper support member can be efficiently supported by the lower support member, and the external force applied to the power steering device can be reduced.

A tenth characteristic configuration of the present invention is that the upper support member includes a shaft-side support member surrounding the steering shaft, and a support base, which is connected to the upper portion of the lower support member in a state surrounding the power steering device. The shaft-side support member is deviated from a support position of the power steering device, and is supported by being connected to an upper portion of the support abutment.

According to this configuration, the shaft-side support member may be formed into a shape or structure suitable for surrounding the steering shaft, and the support abutment may be formed in a shape or suitable for supporting the upper-side support member in a state of surrounding the power steering device. Make up. Thereby, by connecting the support abutment to the upper part of the lower support member, the support strength of the upper support member can be improved, and the steering shaft can be appropriately supported by the upper support member. In addition, the upper support member is formed as a shaft-side support member and a support abutment, respectively, and it is easy to handle, and assembly work of the shaft-side support member and the support abutment can be easily performed.

An eleventh feature of the present invention is that it includes a reinforcing member that connects the shaft-side supporting member and the supporting base, and the reinforcing member supports members other than a supporting member that supports the steering shaft and the power steering device.

According to this configuration, since the reinforcing member connects the shaft-side supporting member with the supporting abutment, the support of the shaft-side supporting member can be reinforced, and the reinforcing member can be used as a member other than the supporting supporting member (for example, an electrical component). Components to use. This makes it possible to simplify the structure and appropriately reinforce the shaft-side supporting member.

A twelfth feature of the present invention is that a manipulator support frame for supporting a manipulator is connected to the shaft-side support member.

According to this configuration, since the support frame for the operation tool is connected to the shaft-side support member, the support frame for the operation tool and the shaft-side support member can be integrally provided. Therefore, with the support member on the upper side, in addition to the steering shaft, and an operation tool arranged around the steering wheel can also be integrated with the support, the support structure can be simplified. Furthermore, not only the external force acting on the steering wheel, but also the external force acting on the operating tool can be prevented from being directly transmitted to the power steering device via the upper support member, and the external force applied to the power steering device can be reduced.

1‧‧‧ Rice transplanter (working vehicle)

6‧‧‧ Engine

7‧‧‧ Transmission

8‧‧‧ front wheel (wheel)

10‧‧‧ hood

15‧‧‧ steering wheel

23‧‧‧ flywheel

24‧‧‧Flywheel cover

41‧‧‧steering shaft

44‧‧‧Upper side support member

45‧‧‧Lower side support member (support member)

45a‧‧‧Hollow Space

46‧‧‧ 1st support member (shaft-side support member)

47‧‧‧ 2nd support member (shaft-side support member)

48‧‧‧ 3rd support member (shaft-side support member)

61‧‧‧Power Steering Device

62‧‧‧ Electric motor

66‧‧‧Support abutment

71‧‧‧Support frame for operating tools

75‧‧‧ Denso components (members other than support members)

81‧‧‧ Transmission

82‧‧‧shift mechanism

100‧‧‧Connecting and connecting part

100a‧‧‧ Connected to the connection part of the connection part

101‧‧‧External Open Department

101a‧‧‧ the connection part of the external open part

C‧‧‧ indicates a line at the center of the support member in a side view

S‧‧‧ Flywheel Tangent

Fig. 1 is a side view showing an overall schematic configuration of the rice transplanter.

Fig. 2 is a left side view showing the main part of the rice transplanter with the hood removed.

Fig. 3 is a plan view showing a main part of the rice transplanter with the hood removed.

FIG. 4 is a perspective view showing a lower portion of a dash board with a rear portion of the hood removed.

FIG. 5 is a diagram showing a schematic configuration of a transmission mechanism.

FIG. 6 is a front view seen from a front side showing a schematic configuration of a steering system.

FIG. 7 is a perspective view seen from a rear side showing a schematic configuration of a steering system.

Fig. 8 is a right side view showing the main part of the steering system.

Fig. 9 is a sectional view showing a main part of a steering system.

An embodiment of a work vehicle according to the present invention will be described with reference to the drawings.

As shown in FIG. 1, a rice transplanter 1 as a work vehicle includes a traveling body 2 and a seedling planting device 3. The seedling planting device 3 is supported by the rear portion of the traveling body 2 through a lifting mechanism 4 so as to be able to lift and lower freely. The seedling planting device 3 is provided with a seedling carrier 31 and a plurality of seedling planting claws 32, and is configured so that the seedlings of the seedling carrier 31 can be planted in the field by the plurality of seedling planting claws 32.

Incidentally, in this embodiment, although the rice transplanter 1 is exemplified as the work vehicle, in addition to the rice transplanter 1, a tractor, a combine harvester, a civil engineering construction device, a snow removing vehicle, and the like, a passenger-type operation can also be applied. vehicle.

The traveling body 2 includes a frame 5 extending in the front-rear direction, and various devices are supported on the frame 5. The frame 5 supports an engine 6 (see FIGS. 2 and 3) as a drive source on the front side thereof, and supports the transmission 7 on the rear side of the engine 6. A hood 10 covering the engine 6 is provided at a front portion of the traveling body 2. Incidentally, FIG. 2 shows the inside of the hood 10 and the left side view of the gearbox 7 with the hood 10 removed, and FIG. 3 shows the inside of the hood 10 and the speed change with the hood 10 removed Plan view of box 7.

Although the illustration is omitted, the transmission 7 includes, for example, a hydraulic-mechanical stepless transmission (HMT: Hydro Mechanical Transmission) and a transmission mechanism that shifts power from the HMT to a plurality of steps. Incidentally, the HMT system combines a hydraulic stepless transmission (HST: Hydro Static Transmission) that can continuously change the power from the engine 6 and a planetary gear mechanism that can synthesize the power from the engine 6 and the power from the HST. Made up.

A front axle box (not shown) is supported at the front of the frame 5, and front wheels 8 are attached to the left and right sides of the front axle box. A rear axle box (not shown) is supported at the rear portion of the frame 5, and rear wheels 9 are attached to the left and right sides of the rear axle box.

The rice transplanter 1 is shown in FIG. 2. The power of the engine 6 is transmitted to the transmission 7 via a power transmission belt 22. The rice transplanter 1 is configured to allow the The output is variable in speed. In addition, the output from the gearbox 7 is freely transmitted to the left and right front wheels 8 and the left and right rear wheels 9, respectively, and the front wheels 8 and the rear wheels 9 are rotationally driven freely.

As shown by the dotted line in FIG. 1, a mounting frame 11 extending in the up-down direction is arranged on the front portion of the vehicle frame 5, and a preparation seedling stage 12 is mounted on the mounting frame 11. The seedling preparation stand 12 is disposed on the left and right sides of the hood 10. The prepared seedlings are placed on the prepared seedling stage 12 so that they can be replenished to the seedling planting device 3.

A driving operation portion 13 is arranged at a middle portion in the front-rear direction of the frame 5. An instrument panel 14 is disposed on a front side of the operation operation portion 13 and a rear end portion of the hood 10. A steering wheel 15 is disposed at a center portion of the instrument panel 14 in the left-right direction, and a driver's seat 16 is disposed at a rear side of the steering wheel 15. The vehicle body cover 17 is provided on the frame 5 covering both sides of the hood 10 in the left-right direction and the rear portion thereof. The operation operation section 13 is provided with various operation tools such as a main shift lever 18, a brake pedal 19 (see FIG. 4), a shift pedal 20 (see FIG. 4), a lift cross lever 21 (see FIG. 4), and the like.

Incidentally, to explain the operating tool, the main shift lever 18 is a lever for shifting the running speed of the traveling body 2 including forward, neutral, and rearward movements. The brake pedal 19 is a pedal for performing a braking operation to apply a braking force to the front wheels 8 or the rear wheels 9. The shift pedal 20 is a pedal for shifting the output from the transmission 7 and operating the traveling speed of the traveling body 2 at a variable speed. The lifting cross bar 21 is a lifting rod for operating the seedling planting device 3 through the lifting mechanism 4. The raising / lowering crossbar 21 is configured to be freely operated by rocking in both the front-rear direction and the left-right direction, and is provided with a detection sensor and the like for detecting the position where the rocking operation is performed.

Hereinafter, a schematic configuration of a steering system for steering the front wheels 8 (wheels) by the rotation operation of the steering wheel 15 will be described with reference to FIGS. 6 and 7.

A steering shaft 41 is provided which is connected to the center portion of the steering wheel 15 and transmits the steering force of the steering wheel 15 to the front wheels 8. Since the periphery of the steering shaft 41 is covered by the support member, the covered portions are indicated by dotted lines in FIGS. 2, 6, and 7. The steering shaft 41 is provided so as to extend in the vertical direction, and an upper end portion thereof is connected to the steering wheel 15. A lower end portion of the steering shaft 41 is connected to the upper portion of the transmission case 7 via a sealing member 42, and the steering shaft 41 is supported on the upper portion of the transmission case 7.

From the upper side, the steering shaft 41 is sequentially divided into three shafts: an upper shaft 41a, an intermediate shaft 41b, and a lower shaft 41c. The upper side shaft 41a is arranged in a backward leaning posture that is positioned more toward the rear side toward the upper side, and the intermediate shaft 41b and the lower side shaft 41c are arranged in a standing posture extending in the vertical direction. The upper shaft 41a and the intermediate shaft 41b are connected so that the joint member 43 rotates integrally. A power steering device 61 is disposed between the intermediate shaft 41b and the lower shaft 41c.

When the user rotates and operates the steering wheel 15, the steering force accompanying the rotation operation is transmitted to the steering shaft 41. An intermediate portion of the steering shaft 41 includes a power steering device 61, and the power steering device 61 includes an electric motor 62, and is configured to be an electric type that is provided to the steering shaft 41 with a driving force of the electric motor 62 as a steering assist force. Thereby, a steering force by the user's steering wheel 15 is applied to the steering shaft 41, and a steering assist force by the electric motor 62 in the power steering device 61 is given. The steering shaft 41 is rotationally driven by the steering force of the steering wheel 15 and the steering assist force of the power steering device 61, and is configured to swing the pitman arm (not shown) by the rotational drive of the steering shaft 41 Operate to operate the direction of the right and left front wheels 8.

The power steering device 61 includes a power steering box 63 disposed between the intermediate shaft 41 b and the lower side shaft 41 c, and an electric motor 62. As shown in FIG. 9, the power steering box 63 has a cylindrical portion with a small diameter arranged on an upper portion of a large diameter cylindrical portion, and is formed into a circular shape in a view, and is inputted in a state extending from an upper end portion to an upper side. The output portion 65 is arranged in a state where the output portion 65 extends downward from the bottom surface portion. The power steering box 63 contains, for example, a shaft portion that transmits a steering force (rotational driving force) input to the input portion 64 and is output to the output portion 65, a drive gear disposed in the middle portion of the shaft portion, and the like (not shown in detail). Torque sensors and more. In addition, as shown in FIG. 9, the power steering device 61 is connected to the intermediate shaft 41 b and is configured to transmit a steering force (rotational driving force) from the intermediate shaft 41 b to the input unit 64. As shown in FIG. 9, the power steering device 61 is connected to the lower side shaft 41 c through a joint member 52 through a joint member 52, and is configured to transmit steering from the output unit 65 to the lower side shaft 41 c through the joint member 52. Force (rotational driving force).

As shown in FIGS. 7 and 9, the electric motor 62 is provided with an output gear that meshes with a drive gear in the power steering box 63, and the drive gear in the power steering box 63 is rotatably driven. The power steering device 61 is configured such that when the steering force (rotational driving force) accompanying the rotation operation of the steering wheel 15 is input from the intermediate shaft 41b to the input portion 64, the steering force (rotational driving force) is added based on electric The steering force (rotational driving force) after the steering assist force (rotational driving force) of the motor 62 is output from the output portion 65 and transmitted to the lower side shaft 41 c via the joint member 52.

The support structure of the steering shaft 41 will be described.

As shown in FIG. 6 and FIG. 7, the upper side support member 44 which can support the steering shaft 41 freely through a bush etc. (illustration omitted) is provided, and the steering shaft 41 is arrange | positioned internally, and the power is steered. The lower side support member 45 supported by the device 61. The upper support member 44 and the lower support member 45 are each configured to extend in the axial center direction of the steering shaft 41 while covering the steering shaft 41.

The upper-side support member 44 is provided so as to cover the outer peripheral portions of the upper-side shaft 41 a and the intermediate shaft 41 b (the upper portion of the steering shaft 41 than the power steering device 61). The lower support member 45 is provided so as to cover an outer peripheral portion of the lower side shaft 41 c (a lower portion of the steering shaft 41 than the power steering device 61).

The upper support member 44 includes, in order from the upper side, a first support member 46 covering a portion corresponding to the upper shaft 41a, a second support member 47 covering a portion corresponding to the joint member 43, and a cover corresponding to the intermediate shaft 41b. A third support member 48 at the portion; and a support abutment 66. The upper support member 44 is supported on the upper portion of the lower support member 45 through a support base 66.

The first support member 46 is formed in a cylindrical shape covering the entire length in the circumferential direction of the upper shaft 41a, and the upper shaft 41a is rotatably supported by a spacer or the like (not shown). Therefore, the upper support member 44 is connected to the steering wheel 15 via an intermediate member such as the upper shaft 41a and a bushing. The second support member 47 is connected to the first support member 46 at the upper end portion, covers the front, upper, and both sides in the left-right direction of the joint member 43 and is formed in a zigzag shape that opens the rear side of the joint member 43. The third support member 48 is a pair of plate-like bodies whose upper ends are connected to the second support member 47, covering the left and right sides of the intermediate shaft 41b, and extending in the front-rear direction to open the front and rear sides of the intermediate shaft 41b. Made up.

As shown in FIG. 9, the lower support member 45 is formed in a cylindrical shape with a hollow space 45 a inside, and the lower shaft 41 c is arranged in the hollow space 45 a. As shown in FIG. 6 and FIG. 9, a seal member 42 is disposed in a lower portion of the lower support member 45, and a seal member 42 is disposed between the lower support member 45 and the transmission 7. The seal member 42 seals (blocks) a portion communicating with the hollow space 45a inside the lower support member 45 to block the inside of the transmission case 7 and the hollow space 45a inside the lower support member 45 to prevent water or oil Waiting to move between the inside of the transmission case 7 and the hollow space 45a inside the lower support member 45.

As shown in FIGS. 7 to 9, the lower support member 45 includes a flange portion 49 extending in a horizontal direction at an upper end portion thereof. The flange portion 49 is formed wider in the front-rear direction and the left-right direction than the outer diameter of the lower support member 45. The lower support member 45 includes an inclined rib portion 51 extending from the outer peripheral portion thereof to the front side or the rear side, and an upper end portion of the rib portion 51 is connected to the flange portion 49. The ribs 51 are provided on the front side of the lower side support member 45 with left and right pairs spaced apart in the left and right direction, and on the rear side of the lower side support member 45 with left and right pairs spaced apart in the left and right direction.

A support structure of the power steering device 61 will be described.

As shown in FIGS. 7 to 9, the power steering box 63 of the power steering device 61 is placed and supported on the flange portion 49 of the lower support member 45. As shown in FIG. 9, at the center portion of the flange portion 49, an opening portion 50 is formed to open the hollow space 45 a inside the lower support member 45, and the opening portion 50 is arranged to block the opening portion 50 from the upper side. Power steering box 63. The power steering box 63 is provided with an output portion 65 protruding downward, and the output portion 65 is arranged so as to extend in the hollow space 45 a through the opening portion 50. Thereby, the output part 65 and the lower side shaft 41c are connected through the joint member 52, and the steering force (rotational driving force) output from the output part 65 is transmitted to the lower side shaft 41c freely via the joint member 52. An opening 67 is formed around the output portion 65 of the power steering box 63, and is configured such that the power is transmitted through the opening 67 of the power steering box 63 and the opening 50 of the flange portion 49 in the lower support member 45. The inside of the steering device 61 communicates with a hollow space 45 a inside the lower support member 45.

In this manner, the power steering box 63 is supported on the flange portion 49 in a state where the inside thereof communicates with the hollow space 45 a inside the lower support member 45. The lower support member 45 is a support member configured to support the power steering device 61 in a state where the steering shaft 41 is located inside the hollow space 45 a and the inside hollow space 45 a is communicated with the inside of the power steering device 61.

The electric motor 62 is provided to be connected to and supported by the power steering box 63 in a state where it extends laterally of the power steering box 63. The electric motor 62 is provided in such a state that the inside thereof communicates with the inside of the power steering box 63.

The upper support member 44 will be described.

The upper support member 44 is integrally provided with an operation tool support structure for supporting operation tools such as the main shift lever 18, the lifting cross bar 21, and the like. As shown in FIGS. 6 and 7, a distal end portion of the second support member 47 of the upper support member 44 is provided with a rod-shaped support frame 71 for a manipulator extending in the left-right direction. A lever guide 72 of the main shift lever 18 is supported at a left end portion of the operation tool support bracket 71, and the main shift lever 18 is supported by the lever guide 72 of the lever guide 72. A support bracket 73 for supporting a detection sensor or the like is provided at a right end portion of the manipulator support frame 71 for detecting a position of the lifting bar 21 (see FIG. 4) or the lifting bar 21.

As described above, as shown in FIG. 7, the upper support member 44 includes the first support member 46, the second support member 47, and the third support member 48, and thereby the first to third support members 46 to 48 constitute the shaft. A side support member that rotatably supports the steering shaft 41 in a state surrounding the steering shaft 41. Among the upper support members 44, the shaft-side support members (the first to third support members 46 to 48) are connected to and supported by the upper portion of the support base 66, and the lower end portion of the support base 66 is connected to the lower support member by supporting them. The upper part of 45 is such that the upper support member 44 is supported on the upper part of the lower support member 45 through the support base 66.

The support base 66 is provided so as to cover the power steering device 61 as shown in FIG. 7. The support abutment 66 is configured to cover the outer peripheral portion of the power steering box 63 at a distance (without contact). The support base 66 covers both sides in the left-right direction and the upper side of the power steering box 63, and is formed in a zigzag shape in a view in the front-back direction opening both sides in the front-back direction. The support abutment 66 is formed on each of the left wall portion 66a covering the left side of the power steering box 63, the right wall portion 66b covering the right side of the power steering box 63, and the upper wall portion 66c covering the upper portion of the power steering box 63. Various members are openings or cutouts through which various members are inserted to arrange the various members at desired positions. As such, the support base 66 is disposed without interference with the power steering device 61.

The support base 66 is supported by a lower end portion of the support base 66 connected to the flange portion 49 of the lower support member 45 by fastening of the nut. The support base 66 is formed in a rectangular shape in a plan view, and is configured such that the width in the front-rear direction and the left-right direction is the same as or substantially the same as the width of the flange portion 49. Further, the four corners of the support base 66 and the flange portion 49 serve as connection support portions of the lower support member 45 toward the flange portion 49.

As shown in FIG. 7 and FIG. 8, the upper support member 44 is connected to the flange portion 49 of the lower support member 45 by a support base 66 arranged at a lower end portion thereof. The first support member 46, the second support member 47, and the third support member 48 are integrally provided by being connected by welding or the like to constitute a shaft-side support member. The lower end portions of the pair of left and right third support members 48 are connected to both sides of the support base 66 in the left-right direction, and the connection between the third support member 48 and the support base 66 is performed by fastening the nuts. Accordingly, the shaft-side support members (the first to third support members 46 to 48) and the support abutment 66 are configured as separate individuals. The third support member 48 and the support abutment 66 cross the entire length of the third support member 48 and the support abutment 66 in the front-rear direction so that the lower end portion of the third support member 48 and the upper wall portion 66c of the support abutment 66 abut. Both ends in the front-back direction become the fastening parts of the nut. The support abutment 66 has a wider width in the left-right direction than the left and right third support members 48, and is configured to stably support the shaft-side support members (the first to third support members 46 to 48).

Since the support abutment 66 covers the outer periphery of the power steering box 63 at intervals (not in contact), the upper support member 44 passes through the flange portion 49 connected to the lower support member 45 to support the abutment 66, The upper support member 44 is supported at the flange portion 49 of the lower support member 45 at a position deviated from the support position of the power steering box 63.

When an external force is generated on the steering wheel 15 when the steering wheel 15 is rotated, the upper support member 44 is connected to the steering wheel 15 through intermediate members such as the upper shaft 41a and the bushing, so that the external force is transmitted to the upper support member 44. . The external force transmitted to the upper support member 44 is transmitted to the flange portion 49 of the lower support member 45 via the support abutment 66 to prevent the external force from being transmitted to the power steering device 61. Therefore, the external force generated on the steering wheel 15 is prevented from being applied to the power steering device 61, and the external force applied to the power steering device 61 can be suppressed to a minimum. In addition, since the operating tool support structure such as the lever guide 72 or the support bracket 73 is integrally provided on the upper support member 44, the external force acting on the operating tool (the main shift lever 18 or the lifting cross bar 21) also passes through the supporting base. 66 is transmitted to the flange portion 49 of the lower support member 45, and external force is prevented from being transmitted to the power steering device 61.

As shown in FIGS. 6 and 7, the operation tool support frame 71 is not only an operation tool support structure such as a lever guide 72 or a support bracket 73, but also includes a connection between the operation tool support frame 71 and a support base 66. The reinforcement frame 74. The reinforcement frame 74 is arranged in a forward leaning position on the right side of the steering shaft 41 on the right side. The lower end portion of the reinforcing frame 74 is connected to the right wall portion 66 b of the support base 66 to increase the support strength of a body (a shaft-side support member) of the first support member 46, the second support member 47, and the third support member 48. In this way, the integrated body (shaft-side support member) of the first support member 46, the second support member 47, and the third support member 48 and the support base 66 are connected by a part of the operation tool support frame 71 and the reinforcing frame 74. The reinforcing member is composed of a part of the operation tool support frame 71 and the reinforcement frame 74. The reinforcing frame 74 not only connects the operation tool support frame 71 and the support base 66, but also supports the electrical component member 75 at an intermediate portion thereof. As a result, a component other than the support member that supports the steering shaft 41 and the power steering device 61, that is, the electric component 75 is supported on the reinforcing member that is constituted by a part of the support frame 71 for the operating tool and the reinforcing frame 74.

As shown in FIGS. 6 and 7, the lower support member 45 not only covers the steering shaft 41, but also connects and supports the gearbox 81 on the left side of the lower support member 45. The transmission 81 is configured by assembling a split box that can be divided in the left-right direction. The transmission 81 houses a transmission mechanism 82 (see FIG. 5) for shifting an output from the transmission 7 in accordance with a shift operation.

As shown in FIG. 5, the speed change mechanism 82 includes a speed change operation shaft 83 that extends in the left-right direction and is rotatable. The base portion of the sector gear 84 and the first arm 85 is fixed to the shift operation shaft 83, and the shift operation shaft 83, the sector gear 84, and the first arm 85 are rotatably provided integrally. An actuator 87 (electric motor) for rotating and driving the pinion gear 86 meshed with the sector gear 84 is provided. The pinion gear 86 is rotationally driven by the actuator 87, and the transmission operating shaft 83 is rotationally driven through the sector gear 84.

The front end portion of the first arm 85 is connected to a shift lever 93 extending rearward, and is configured to operate the shift lever 93 to move in the front-rear direction by rotation of the shift operation shaft 83. Although not shown in the figure, the rear end portion of the shift lever 93 is linked to a trunnion in the HST inside the transmission 7 through a link mechanism or the like. Thereby, the structure is such that the swash plate angle of the HST is adjusted to a desired angle by operating the shift lever 93 in the front-rear direction and operating the trunnion, so that the output (running speed) from the transmission 7 can be steplessly shifted.

An arc-shaped cam groove 88 is formed in the sector gear 84, and the second arm 89 is provided with a distal end portion that can be freely engaged in the cam groove 88. A horizontal axis 90 extending in the left-right direction and rotatably provided is provided. A proximal end portion of the second arm 89 and a proximal end portion of the third arm 91 are connected to the horizontal axis 90. When the sector gear 84 is rotated, the front end portion of the second arm 89 moves in the cam groove 88 to rotate the horizontal axis 90, and the third arm 91 is operated to swing. A metal wire 92 is connected to the front end of the third arm 91, and a throttle lever of the engine 6 is connected to the other end of the metal wire 92. In this way, the throttle lever is linked in response to the rocking operation of the third arm 91, and the output (running speed) from the gearbox 7 is continuously variable to adjust the engine rotation of the engine 6 speed.

As shown in FIG. 4, the shift pedal 20 is disposed on the lower right side of the instrument panel 14 in the operation operation unit 13, and includes a potentiometer and the like (not shown) for detecting the depression amount of the shift pedal 20. Then, the actuator 87 (see FIG. 5) in the transmission mechanism 82 is rotationally driven so that the swash plate angle of the HST becomes a desired angle in accordance with the depression amount of the transmission pedal 20. Accordingly, the transmission mechanism 82 shifts the output (running speed) from the transmission 7 to a desired shifting state in response to the depression operation of the shift pedal 20 by the user.

As shown in FIG. 9, since the lower support member 45 has a hollow space 45 a inside, the lower support member 45 has a configuration in which the inside of the gearbox 7 is opened to the outside using the hollow space 45 a and the inside of the power steering device 61 is opened to the outside.

As shown in FIG. 8, it includes a communication connection portion 100 that connects the transmission case 7 and the lower support member 45 in a state where the inside of the transmission case 7 communicates with the inside of the lower support member 45; and a lower support member The inside of 45 is an outside open portion 101 which is opened to the outside. The communication connection portion 100 is constituted by a transmission pipe for a transmission that connects the inside of the transmission case 7 and the inside of the lower support member 45 in communication with each other. A hole portion penetrating the outer wall portion of the lower side support member 45 is formed at a connection portion 100 a of the communication connection portion 100 to the lower side support member 45, whereby the hole portion is communicated with the inside of the lower side support member 45. The external open portion 101 is configured by a vent pipe that connects the inside of the lower support member 45 to the outside in communication. The external open portion 101 doubles as the ventilation duct that connects the inside of the transmission case 7 to the outside through the inside of the lower support member 45, and the power steering device 61 The inside of the ventilator communicates with the outside ventilating tube via the inside of the lower support member 45. A hole portion penetrating the outer wall portion of the lower side support member 45 is formed in a connection portion 101a of the outer open portion 101 to the lower side support member 45, whereby the hole portion is communicated with the inside of the lower side support member 45. The external open portion 101 is arranged so as to extend upward around the steering shaft 41. The upper end portion of the external open portion 101 is open to cover the space on the front upper side and the left and right sides by the second support member 47 of the upper side support member 44.

Since the inside of the transmission case 7 and the inside of the lower side support member 45 are connected and communicated through the communication connection part 100, as shown in FIGS. 8 and 9, the air inside the transmission case 7 can be temporarily moved to the lower side support member 45. The hollow space 45a is supplied. Then, since the hollow space 45a of the lower support member 45 is opened to the outside through the external opening portion 101, the air supplied to the hollow space 45a of the lower support member 45 can be finally exhausted to the outside. Thereby, opening the inside of the gearbox 7 to the outside allows the pressure inside the gearbox 7 to escape to the outside, and prevents the inside of the gearbox 7 from becoming high pressure.

As shown in FIG. 9, the power steering device 61 is provided in a state where the inside of the power steering box 63 of the power steering device 61 communicates with the hollow space 45 a of the lower support member 45. Therefore, heat and water vapor inside the power steering device 61 can be temporarily supplied to the hollow space 45 a of the lower support member 45. Then, as shown in FIG. 8 and FIG. 9, since the hollow space 45 a of the lower support member 45 is opened to the outside through the external opening portion 101, heat and water vapor supplied to the hollow space 45 a of the lower support member 45 can be supplied. , And finally radiate or release to the outside. Thereby, the heat and water vapor inside the power steering device 61 can be radiated or released to the outside, and the inside of the power steering device 61 can be prevented from becoming hot, and moisture such as dew condensation can be accumulated inside the power steering device 61.

As shown in FIG. 8, both the communication connection portion 100 and the external open portion 101 are arranged on the right side of the lower support member 45 and on the right side of the steering shaft 41. Further, the connection portion 100 a of the communication connection portion 100 to the lower support member 45 and the connection portion 101 a of the external opening portion 101 to the lower support member 45 are arranged at intervals in the front-rear direction and the up-down direction. Incidentally, in FIGS. 6 and 7, the communication connection portion 100 and the external open portion 101 are omitted, and only the connection portion 100 a of the communication connection portion 100 to the lower support member 45 and the external open portion 101 to the lower support member are shown. 45 的 连接 部 101a。 The connecting portion 101a of 45.

As shown in FIG. 8, the connection portion 101 a that connects the connection portion 100 a of the connection portion 100 and the external open portion 101 is the central portion of the lower side support member 45 in the side view (see FIG. 8, C (Dotted line). The connection portion 100a of the communication connection portion 100 is disposed rearward of the center portion of the lower side support member 45, and the connection portion 101a of the external opening portion 101 is disposed at the center portion of the lower side support member 45 and further forward thereof. side. The connection portion 101 a of the external open portion 101 is disposed above the connection portion 100 a of the communication connection portion 100 in the vertical direction. The connection portion 100 a of the communication connection portion 100 is disposed at the upper end portion of the lower support member 45, and the connection portion 101 a of the external open portion 101 is disposed at the middle portion in the vertical direction of the lower support member 45.

The arrangement relationship between the electric motor 62 and other devices in the power steering device 61 will be described below.

As shown in FIGS. 6 and 7, the electric motor 62 of the power steering device 61 is provided with a steering assist force from a lateral side orthogonal to the axial center direction of the steering shaft 41, and is therefore disposed on the lateral side of the steering shaft 41. As shown in FIG. 2, the electric motor 62 is arranged on the rear side of the engine 6 in the front-rear direction and on the front side of the steering shaft 41. In this way, the space between the engine 6 and the steering shaft 41 is effectively utilized to arrange the electric motor 62, and the engine 6, the steering shaft 41, the power steering device 61, and the like are efficiently arranged in a limited space in the hood 10.

As shown in FIGS. 6 and 7, a transmission 81 is arranged on the lower side support member 45 on the left side thereof. The transmission 81 houses a transmission mechanism 82 (see FIG. 5) that shifts the output from the transmission 7 by operating a trunnion of the HST. The gearbox 81 is arranged on the left side in the left-right direction with respect to the steering shaft 41. The trunnion of HST is also arranged on the left side in the left-right direction with respect to the steering shaft 41. The trunnions of the gearbox 81 and HST are arranged with respect to the steering shaft. 41 on the same side in the left and right direction. With this, it is possible to simplify the length or configuration of the shift lever 93 that connects the transmission 81 to the trunnion of the HST. As shown in FIGS. 6 and 7, the electric motor 62 is also disposed on the left side of the lower support member 45, and the transmission 81 and the electric motor 62 are integrated and disposed on the left side in the left-right direction with respect to the steering shaft 41. The electric motor 62 is disposed on the upper side than the transmission 81, and is efficiently disposed in a space on the upper side of the transmission 81 while suppressing interference between the electric motor 62 and the transmission 81. As shown in FIG. 2, a part of the electric motor 62 and a part of the transmission 81 are arranged in the front-rear direction so as to overlap.

By arranging the transmission 81 and the electric motor 62 on the left side in the left-right direction with respect to the steering shaft 41, it is not necessary to secure the arrangement space of the electric motor 62 or the transmission 81 on the right in the left-right direction with respect to the steering shaft 41. Therefore, a larger space can be secured on the right side than the steering shaft 41. As shown in FIG. 4, the oil filter 25 and the fuel supply port 26 of the engine 6 are arranged on the right side in the left-right direction with respect to the steering shaft 41. Therefore, by utilizing a larger space on the right side than the steering shaft 41, maintenance work of the engine 6 and the like can be performed, and maintenance work can be simplified.

As shown in FIGS. 2 and 3, a flywheel 23 is arranged at the left end portion of the engine 6, and a flywheel cover 24 is provided to cover the flywheel 23 from the upper side. The flywheel cover 24 is configured to cover not only the upper side of the flywheel 23 but also the rear side of the flywheel 23. The flywheel cover 24 is formed in an arc shape, and the arc shape is provided with a portion extending forward and backward in the upper portion of the flywheel 23 and a rear end portion of the portion extending in the forward and backward direction continuing to the lower rear side to the flywheel 23 To the rear side. The flywheel cover 24 provided with such a shape prevents muddy water and the like from flying upward.

Then, as shown in FIG. 2, the electric motor 62 is arranged above the tangent line (the broken line of S in FIG. 2) of the flywheel 23 passing through the outer peripheral portion of the flywheel 23 and the lower end portion of the flywheel cover 24. Thus, by disposing the electric motor 62, the electric motor 62 can be disposed at a position where the flywheel cover 24 prevents the scattering of muddy water, thereby preventing the electric motor 62 from being adversely affected by the scattering of muddy water and the like. The gearbox 81 is also disposed above the tangent line (the broken line of S in FIG. 2) of the flywheel 23 passing through the outer peripheral portion of the flywheel 23 and the lower end portion of the flywheel cover 24.

    [Other embodiment]    

(1) In the above embodiment, the electric motor 62 and the gearbox 81 are arranged on the left side of the steering shaft 41, but the electric motor 62 and the gearbox 81 may be arranged on the right side of the steering shaft 41. Alternatively, the electric motor 62 and the transmission 81 may be distributed to the left and right of the steering shaft 41.

(2) In the above embodiment, the transmission 81 is disposed in the hood 10, but the transmission 81 may be omitted.

(3) In the above embodiment, the steering shaft 41 is divided into three shafts, such as an upper shaft 41a, an intermediate shaft 41b, and a lower shaft 41c. However, the division into several shafts may be appropriately changed. For example, the One shaft constitutes the steering shaft 41.

In addition, the posture of the steering shaft 41 can be applied to various postures such as a reclining posture in which the vehicle is lowered toward the front side and a standing posture extending in the up-down direction.

(4) In the above embodiment, the communication connection portion 100 is provided, and the communication connection portion 100 connects the transmission case 7 and the lower support member 45 in a state where the inside of the transmission case 7 communicates with the inside of the lower support member 45. , But the communication connection portion 100 may be omitted.

(5) In the above-mentioned embodiment, although the connection portion 100a of the communication connection portion 100 to the lower support member 45 is disposed on the upper side than the connection portion 101a of the external open portion 101 to the lower support member 45, it may be reversed. The connection portion 101 a of the external open portion 101 to the lower support member 45 may be disposed above the connection portion 100 a of the communication connection portion 100 to the lower support member 45.

(6) In the above embodiment, the connection portion 100a of the communication connection portion 100 to the lower support member 45 and the connection portion 101a of the external open portion 101 to the lower support member 45 are disposed on the right side of the lower support member 45. However, for example, the connection portion 100a of the communication connection portion 100 to the lower support member 45 and the connection portion 101a of the external opening 101 to the lower support member 45 may be scattered on the left and right sides of the lower support member 45. Configuration. In this way, it is possible to appropriately change which part of the circumferential direction of the lower support member 45 the connection portion 100a of the communication connection portion 100 to the lower support member 45 and the connection portion 101a of the external open portion 101 to the lower support member 45 can be appropriately changed. .

(7) In the above embodiment, the power steering device 61 is configured as an electric type including an electric motor 62. For example, the power steering device 61 may be configured as a hydraulic type including a hydraulic motor, and is not limited to the electric type.

(8) In the above embodiment, the shaft-side support member composed of the first to third support members 46 to 48 in the upper support member 44 and the support base 66 are separately formed, but the first to third support members 44 may also be formed The shaft-side support member composed of the third support members 46 to 48 is integrally formed with the support base 66.

(9) In the above embodiment, the connection portion of the support base 66 to the flange portion 49 of the lower support member 45 may be a position deviating from the support position of the power steering box 63. It is possible to change which part of the connection part is appropriate.

    [Industrial availability]    

The present invention is applicable to various work vehicles including a steering shaft that transmits a steering force of a steering wheel to a wheel and a power steering device that imparts a steering assist force to the steering shaft.

Claims (12)

    A work vehicle comprising: an engine; a gearbox that transmits driving force from the engine; a steering shaft that transmits steering force of a steering wheel to wheels; a power steering device that imparts a steering assist force to a steering shaft thereof; It is configured such that the driving force of an electric motor is given to the electric type of the steering shaft, the steering shaft is supported on the upper part of the transmission, the engine, the steering shaft, and the power steering device are arranged in a hood, and the electric The motor system is disposed rearwardly of the engine and frontwardly of the steering shaft in the front-rear direction.         For example, the work vehicle according to claim 1, wherein a gearbox having a transmission mechanism is provided in the hood to change the output from the gearbox in accordance with a shift operation, and the gearbox is disposed on the upper part of the gearbox. The electric motor is disposed above the transmission.         The work vehicle according to claim 2, wherein the electric motor and the gearbox are disposed on the same side in the left-right direction with respect to the steering shaft.         The work vehicle according to any one of claims 1 to 3, which includes a flywheel cover for covering the flywheel of the engine from above, and the electric motor is disposed at a position which is higher than the distance between the outer peripheral portion of the flywheel and the lower end portion of the flywheel cover. The tangent of the flywheel is also on the upper side.         If the work vehicle of claim 1 includes a support member that supports the steering shaft and the power steering device, the support member is configured to support the steering shaft in a state where the steering shaft is located in a hollow space inside the steering shaft, and The power steering device is supported in a state in which a hollow space inside the power steering device is communicated with the inside of the power steering device. The power steering device includes an external opening portion and opens the inside of the support member to the outside.         The work vehicle according to claim 5, wherein the transmission case supports a lower end portion of the support member and transmits a driving force to a wheel, and includes a communication connection portion in a state where the inside of the transmission case communicates with the inside of the support member. The aforementioned transmission is connected to the aforementioned supporting member.         The work vehicle according to claim 5 or 6, wherein the connection portion of the communication connection portion to the support member is disposed above the connection portion of the external opening portion to the support member.         The work vehicle according to any one of claims 5 to 7, wherein the connection portion of the communication connection portion to the support member and the connection portion of the external opening portion to the support member are sandwiched with the support in a side view. The central portion of the member is arranged in a state of being separated in the front-rear direction.         The work vehicle according to claim 1, wherein the power steering device is disposed at a halfway portion of the steering shaft, and includes a lower support member extending in a state surrounding the steering shaft and a lower portion than the power steering device. In the axial center direction of the steering shaft; and an upper support member connected to the steering wheel through an intermediate member, and extending to the axial center of the steering shaft in a state surrounding the steering shaft above the power steering device Direction, the steering shaft and the lower support member are supported on the upper part of the transmission, the power steering device is supported on the upper part of the lower support member, and the upper support member is on the upper part of the lower support member. , Is supported at a position deviating from the support position of the power steering device.         The work vehicle according to claim 9, wherein the upper support member includes: a shaft-side support member surrounding the steering shaft; and a support base, which is connected to the upper portion of the lower support member in a state surrounding the power steering device. The shaft-side support member is deviated from a support position of the power steering device, and is supported by being connected to an upper portion of the support abutment.         The work vehicle according to claim 10, further comprising a reinforcing member that connects the shaft-side supporting member and the supporting abutment, and the reinforcing member supports a member other than a supporting member that supports the steering shaft and the power steering device.         The work vehicle according to claim 10 or 11, wherein a support frame for an operating tool that supports the operating tool is connected to the aforementioned shaft-side supporting member.