JP6991105B2 - Passenger work vehicle - Google Patents

Description

In the present invention, the traveling vehicle body is provided with a vehicle body frame, a plurality of traveling wheels, and an engine for driving the plurality of traveling wheels, and the power of the engine is said to travel via a lateral transmission shaft and a vertical transmission shaft. The present invention relates to a passenger-type work vehicle that is transmitted to wheels and is supported so that the traveling wheels are reorientably supported around the rotation axis of the vertical transmission shaft with respect to the vehicle body frame.

In this type of passenger-type work vehicle, conventionally, a vertical transmission shaft and a vertical case covering the vertical transmission shaft are provided long in the vertical direction, and the ground clearance of the traveling vehicle body is increased to have a high clearance specification. There was something. The vertical case is formed in a double cylinder structure with an upper case part and a lower case part, the upper case part is fixed to the vehicle body frame, and the lower case part is provided so that the direction can be changed integrally with the traveling wheel. Was being done. The vertical length of the vertically oriented case is set to a predetermined constant length (see, for example, Patent Document 1).

With this configuration, for example, a fertilizer application device or a chemical spraying device is attached to the rear part of the traveling vehicle body, and chemicals such as fertilizer and herbicide are supplied to the crop while the left and right traveling wheels straddle the ridges and travel in the field. It is possible to raise the ground height of the traveling vehicle body so that the traveling vehicle body does not come into contact with the ridges formed in the field or the planted crops.

Japanese Patent Application Laid-Open No. 2003-94907

The work vehicle having the above-mentioned conventional configuration can drive the traveling wheel via the vertical transmission shaft, and the traveling wheel is smoothly rotated by rotating the vertical case around the axis of the vertical transmission shaft. It is possible to change the direction to. However, in the above-mentioned conventional configuration, since the vertical length of the vertical case is fixed to be constant, there is a disadvantage that the ground clearance of the traveling vehicle body becomes excessive or insufficient due to the difference in the growing condition and type of crops or the difference in working conditions. was there. For example, if the crop grows well and is tall, the vehicle body may come into contact with the crop at the same ground clearance. In addition to that, when the work vehicle goes in and out of the field and travels over the ridges, there is a risk that the ground clearance of the traveling vehicle body will be too high and the posture will become unstable at the same ground clearance.

Therefore, while making it possible to perform rotational drive and turning operation of the traveling wheels well, the ground clearance of the traveling vehicle body is adjusted to the optimum height according to the growing condition of the crop, the type of crop, the difference in the working condition, etc. It was desired to be able to set it.

The characteristic configuration of the passenger-type work vehicle according to the present invention is that the traveling vehicle body is provided with a vehicle body frame, a plurality of traveling wheels, and an engine for driving the plurality of traveling wheels, and the power of the engine is a lateral transmission shaft and a lateral transmission shaft. It is transmitted to the traveling wheel via the vertical transmission shaft, and the traveling wheel is supported so as to be reorientably oriented around the rotation axis core of the vertical transmission shaft with respect to the vehicle body frame. Each of the vertical transmission shaft and the vertical transmission case that covers the circumference of the vertical transmission shaft is configured as an internal / external double structure that can expand and contract while sliding in the axial direction of the vertical transmission shaft, and the vertical orientation. The transmission case is rotatably supported around the rotation axis of the vertical transmission shaft with respect to the vehicle body side case supported by the vehicle body frame integrally with the traveling wheel, and the vertical transmission shaft and the transmission case are rotatably supported. The vehicle height adjustment mechanism is provided with a vehicle height adjustment mechanism capable of switching the relative height of the traveling wheel with respect to the vehicle body frame in a plurality of stages by expanding and contracting the vertical transmission case in the axial center direction . As a plurality of hydraulic cylinders extending along the axis direction, an upper hydraulic cylinder that can be extended toward the upper side and a lower hydraulic cylinder that can be extended toward the lower side are provided, and the vehicle height can be adjusted. The mechanism is the shortest state in which the upper hydraulic cylinder and the lower hydraulic cylinder are retracted, an intermediate extension state in which one of the upper hydraulic cylinder and the lower hydraulic cylinder is retracted and the other is extended, and an intermediate extension state. The upper hydraulic cylinder and the lower hydraulic cylinder can be switched to the three states of the maximum extended state, and the relative height can be switched to three stages .

According to this configuration, by operating the vehicle height adjusting mechanism, the vertical transmission shaft and the vertical transmission case each expand and contract while sliding. As a result, the relative height of the traveling vehicle body frame can be changed and adjusted, and the ground clearance of the traveling vehicle body can be changed by adjusting the height of each of the plurality of traveling wheels.
In this way, the vertical transmission shaft and the vertical transmission case are configured to expand and contract while sliding, as compared with a configuration in which the traveling wheels are supported so as to be able to move up and down by using, for example, a refraction link or the like. The amount of protrusion to the outside is small, and it is possible to set the adjustment amount of the vehicle height longer while having a compact shape in a plan view.
In addition, since the vertical transmission case can rotate integrally with the traveling wheels, the traveling wheels can be smoothly oriented by rotating the vertical transmission case regardless of the position of the ground height of the traveling vehicle body. Can be changed. Moreover, even if the vertical transmission shaft is expanded and contracted, it is possible to transmit rotational power to the traveling wheels.
Therefore, the ground clearance of the traveling vehicle body is adjusted to the optimum height according to the growing condition of the crop, the type of crop, the difference in the working condition, etc., while enabling the rotational drive and the turning operation of the traveling wheel to be performed well. It is now possible to set it.

In the present invention, the vehicle height adjusting mechanism is provided with a base member that supports the plurality of hydraulic cylinders, and the vertical transmission case has an inner / outer double structure in which an inner cylinder member and an outer cylinder member are slid. It is preferable that the outer peripheral side of the overlapping portion where the inner cylinder member and the outer cylinder member overlap is supported by the base member in a state where the inner cylinder member can be expanded and contracted while moving and in the most extended state.
According to this configuration, in order to make the vertical transmission case expandable and contractible, the inner cylinder member and the outer cylinder member are configured to expand and contract while sliding. Further, since the vehicle height adjusting mechanism includes a plurality of hydraulic cylinders extending along the axis direction, it is possible to expand and contract the vertical transmission case in a smooth state without fear of squeezing or the like.
In the vertical transmission case, in the extended state, the overlapping portion where the inner cylinder member and the outer cylinder member overlap becomes narrower along the expansion / contraction direction, so that the rigidity is reduced and the supporting strength for supporting the traveling wheel is reduced. However, it is possible to prevent a decrease in rigidity by supporting the outer peripheral side of the overlapping portion of the vertical transmission case by using the base member in the vehicle height adjustment mechanism.
Therefore, it is necessary to effectively utilize the base member required to support a plurality of hydraulic cylinders in the vehicle height adjustment mechanism to prevent a decrease in the support strength due to the vertical transmission case and stably support the traveling wheels. Is now possible.

Another characteristic configuration of the passenger-type work vehicle according to the present invention is that the traveling vehicle body is provided with a vehicle body frame, a plurality of traveling wheels, and an engine for driving the plurality of traveling wheels, and the power of the engine is transmitted laterally. It is transmitted to the traveling wheel via the shaft and the vertical transmission shaft, and the traveling wheel is supported so as to be reorientably oriented around the rotation axis core of the vertical transmission shaft with respect to the vehicle body frame. Each of the vertical transmission shaft and the vertical transmission case that covers the periphery of the vertical transmission shaft is configured as an internal / external double structure that can expand and contract while sliding in the axial direction of the vertical transmission shaft. The vertical transmission case is rotatably supported around the rotation axis of the vertical transmission shaft with respect to the vehicle body side case supported by the vehicle body frame integrally with the traveling wheel, and the vertical transmission shaft is supported. And, the vehicle height adjustment mechanism capable of switching the relative height of the traveling wheel with respect to the vehicle body frame in a plurality of stages by expanding and contracting the vertical transmission case in the axial center direction is provided. A plurality of hydraulic cylinders extending along the axis direction and a base member for supporting the plurality of hydraulic cylinders are provided, and the vertical transmission case has an inner and outer double structure, that is, an inner cylinder member and an outer cylinder. It is possible to expand and contract while sliding with the member, and in the most extended state, the outer peripheral side of the overlapping portion where the inner cylinder member and the outer cylinder member overlap is supported by the base member.

According to this configuration, by operating the vehicle height adjusting mechanism, the vertical transmission shaft and the vertical transmission case each expand and contract while sliding. As a result, the relative height of the traveling vehicle body frame can be changed and adjusted, and the ground clearance of the traveling vehicle body can be changed by adjusting the height of each of the plurality of traveling wheels.
In this way, the vertical transmission shaft and the vertical transmission case are configured to expand and contract while sliding, as compared with a configuration in which the traveling wheels are supported so as to be able to move up and down by using, for example, a refraction link or the like. The amount of protrusion to the outside is small, and it is possible to set the adjustment amount of the vehicle height longer while having a compact shape in a plan view.
In addition, since the vertical transmission case can rotate integrally with the traveling wheels, the traveling wheels can be smoothly oriented by rotating the vertical transmission case regardless of the position of the ground height of the traveling vehicle body. Can be changed. Moreover, even if the vertical transmission shaft is expanded and contracted, it is possible to transmit rotational power to the traveling wheels.
Therefore, the ground clearance of the traveling vehicle body is adjusted to the optimum height according to the growing condition of the crop, the type of crop, the difference in the working condition, etc., while enabling the rotational drive and the turning operation of the traveling wheel to be performed well. It is now possible to set it.
Further, according to this configuration, in order to make the vertical transmission case expandable and contractible, the inner cylinder member and the outer cylinder member are configured to expand and contract while sliding. Further, since the vehicle height adjusting mechanism includes a plurality of hydraulic cylinders extending along the axis direction, it is possible to expand and contract the vertical transmission case in a smooth state without fear of squeezing or the like.
In the vertical transmission case, in the extended state, the overlapping portion where the inner cylinder member and the outer cylinder member overlap becomes narrower along the expansion / contraction direction, so that the rigidity is reduced and the supporting strength for supporting the traveling wheel is reduced. However, it is possible to prevent a decrease in rigidity by supporting the outer peripheral side of the overlapping portion of the vertical transmission case by using the base member in the vehicle height adjustment mechanism.
Therefore, it is necessary to effectively utilize the base member required to support a plurality of hydraulic cylinders in the vehicle height adjustment mechanism to prevent a decrease in the support strength due to the vertical transmission case and stably support the traveling wheels. Is now possible.

In the present invention, the vehicle body side case is provided with a support boss portion that rotatably supports the vertical transmission case, and the support boss portion is located on the radial inward side of the vertical transmission case. Therefore, it is preferable that the bolt is provided so as to extend downward along the axis direction.

According to this configuration, the vertical transmission case is rotatably supported by the support boss portion provided on the vehicle body side case. Since the support boss portion is located on the radial inward side of the vertical transmission case and extends downward along the axis direction, the support of the vertical transmission case is caused by the telescopic configuration. It is possible to prevent a decrease in strength, stably support the traveling vehicle body by the traveling wheels, and to perform a good turning operation of the traveling wheels.

It is an overall side view of a work platform. It is a top view which shows the wheel support structure of a work vehicle. It is a front view which shows the wheel support structure. It is a perspective view of a part of a wheel support structure. It is a perspective view of a part of a wheel support structure. It is a top view which shows the engaging state of the actuating arm. It is a cross-sectional front view of the vehicle height adjustment mechanism in the maximum extension state. It is a cross-sectional front view of the vehicle height adjustment mechanism in the intermediate extension state. It is a cross-sectional front view of the vehicle height adjustment mechanism in the shortest state. It is a figure which shows the base member. It is a cross-sectional plan view of a base member. It is sectional drawing which shows the structure of a stroke sensor. It is sectional drawing which shows the structure of the stroke sensor of another embodiment.

Hereinafter, embodiments of the passenger-type work platform according to the present invention will be described with reference to the drawings.

〔overall structure〕
FIG. 1 shows a passenger-type work vehicle according to the present invention. This work vehicle is provided with a chemical spraying device 2 as a work device at the rear of the four-wheel traveling type traveling vehicle body 1. In this work vehicle, in a field where crops have already been planted, the work of spraying the chemicals on the crops while traveling across the crop planting strips is performed.

A pair of front wheels 3 as traveling wheels S capable of turning can be provided on both left and right sides of the front portion of the traveling vehicle body 1, and a pair of rear wheels 4 as traveling wheels S capable of turning operation on both left and right sides of the rear portion of the traveling vehicle body 1. Is provided. In this way, all four wheels can turn, for example, a two-wheel steering state in which only two front wheels 3 are turned, and four wheels in which the front wheels 3 and the rear wheels 4 are turned in opposite directions to travel with a small turning radius. It is possible to switch to the steering state.

The front wheels 3 and the rear wheels 4 are formed to be narrow so that they can run between the strips located between the crop strips. The engine 5 is mounted on the front portion of the traveling vehicle body 1, and the driving unit 6 is provided on the rear portion of the traveling vehicle body 1. A mission case 7 including a transmission (not shown) for shifting the power of the engine 5 is provided in the lower portion of the traveling vehicle body 1. The mission case 7 is provided so as to extend in the front-rear direction from the lower rear portion of the engine 5 to a portion corresponding to the rear wheel 4 in a side view. A front frame body 8 is provided on the lower side of the engine 5 so as to cover the outer peripheral portion. The mission case 7 and the front side frame body 8 are integrally connected to each other, thereby forming a vehicle body frame F that supports the entire vehicle body. The driver unit 6 is provided with a driver's seat 9 in which the driver sits, and a steering handle 10 located in front of the driver's seat 9 to perform steering operation. In addition to this, the driving unit 6 is also provided with an elevating lever 11 for raising and lowering the working device, a speed change lever 12, and the like.

In the traveling vehicle body 1, the power of the engine 5 is transmitted to the left and right front wheels 3 and the left and right rear wheels 4 after the power of the engine 5 is changed by the transmission in the transmission case 7. Therefore, the traveling vehicle body 1 is configured as a four-wheel drive type in which four traveling wheels S are driven. As shown in FIG. 2, a lateral transmission shaft 14 is provided inside a cylindrical rear lateral transmission case 13 (an example of a vehicle body side case) connected to both left and right sides of the mission case 7, and power after shifting is transmitted laterally. It is transmitted to the rear wheels 4 on both the left and right sides via the shaft 14. The rear lateral transmission case 13 is supported by the mission case 7, that is, the vehicle body frame F.

As shown in FIG. 2, a cylindrical front lateral transmission case 15 (an example of a vehicle body side case) is provided in the left and right middle portions of the left and right front wheels 3, and the power from the mission case 7 is an intermediate shaft 16 in the front-rear direction. , It is transmitted to the left and right front wheels 3 via a differential mechanism (not shown) provided in the lateral transmission case 15 and the lateral transmission shaft 18. The front lateral transmission case 15 is freely rolled around the front-rear shaft core X, which is the same shaft core as the intermediate shaft 16 with respect to the vehicle body frame F.

As shown in FIG. 3, a vertical transmission case 19 is connected to both left and right ends of the front lateral transmission case 15. Then, as shown in FIG. 7, a vertical transmission shaft 20 is provided in the vertical transmission case 19. The shaft end portion of the lateral transmission shaft 18 provided in the front lateral transmission case 15 and the upper end portion of the vertical transmission shaft 20 are interlocked and connected via the upper bevel gear mechanism 21. The lower end of the vertical transmission shaft 20 and the rotation shaft 3a of the front wheel 3 are interlocked and connected via the lower bevel gear mechanism 22.

The traveling wheel S is supported so as to be reorientable around the rotation axis Y of the vertical transmission shaft 20 with respect to the vehicle body frame F. Since the support structure of the wheel having the vertical transmission case 19 and the vertical transmission shaft 20 has the same configuration for each of the four traveling wheels S, the support structure of one of the front wheels 3 is as follows. Explain to.

[Wheel support structure]
As shown in FIGS. 4, 5 and 7, the end portion of the front lateral transmission case 15 has a shape that bends in a curved shape when viewed from the front while covering the upper bevel gear mechanism 21, and has an opening that opens downward. It is formed. The upper connecting body 23 integrally connected to the upper end of the vertical transmission case 19 rotates around the rotation axis Y of the vertical transmission shaft 20 at the end of the front horizontal transmission case 15 so as to cover the opening. Movably fitted and connected. As shown in FIG. 7, a wheel support case 24 for supporting the rotating shaft 3a of the front wheel 3 is connected to the lower end portion of the vertical transmission case 19 while covering the lower bevel gear mechanism 22.

A retaining tool 25 is provided to prevent the upper connecting body 23 from coming off in a state where the upper connecting body 23 is fitted and connected. As shown in FIG. 5, the retaining tool 25 is made of a strip-shaped member, one end thereof is bolted to the outer peripheral portion of the upper connecting body 23, and the other end portion is connected to the end portion of the front lateral transmission case 15. It engages with the formed step portion 26 to prevent it from coming off.

As shown in FIGS. 2, 3 and 4, a double-acting hydraulic cylinder 27 for steering operation (hereinafter,) located in front of the front lateral transmission case 15 and in a posture parallel to the front lateral transmission case 15. , Called a steering cylinder). The cylinder tube 28 of the steering cylinder 27 is connected to the front lateral transmission case 15 via the bracket 29. The piston rod 30 of the steering cylinder 27 is interlocked with one end of the tie rod 32 via the ball joint 31, and the other end of the tie rod 32 is interlocked with the knuckle arm 34 provided on the upper connecting body 23 via the ball joint 33. It is connected.

By operating the steering cylinder 27, the vertical transmission case 19, the wheel support case 24, and the front wheel 3 are integrally connected to the rotation shaft core Y of the vertical transmission shaft 20 via the knuckle arm 34 and the upper connecting body 23. The front wheel 3 is rotated around to change the direction of the front wheel 3. The hydraulic control valve of the steering cylinder 27 is switched and operated by a control device (not shown) according to the operation of the steering handle 10, and is hydraulically slid to the left or right from the neutral position for straight traveling.

A rotation angle detecting device 35 for detecting the rotation angle of the upper connecting body 23, that is, the rotation angle of the front wheel 3 is provided on the upper portion of the end portion of the front lateral transmission case 15. The rotation angle detecting device 35 includes a potentiometer-type detecting device main body 36 provided in a fixed state on the upper portion of the front lateral transmission case 15, and a strip-shaped operating arm 37. One end of the actuating arm 37 is bolted to the outer peripheral portion of the upper connecting body 23, and the other end thereof is integrally rotatably engaged with a rotating shaft 38 protruding downward from the detection device main body 36.

As shown in FIGS. 3 and 4, the outer peripheral portion of the detection device main body 36 is covered with a casing 39, and the casing 39 is connected to the upper portion of the end portion of the front lateral transmission case 15. The actuating arm 37 is provided in a state of extending diagonally upward from the connection point with respect to the upper connecting body 23. As shown in FIG. 6, the rotating shaft 38 is processed so that the cross section has a rectangular shape, and the rectangular engaging groove 40 formed at the other end of the operating arm 37 is engaged with the rotating shaft 38. It is interlocked with the operating arm 37 in a state of being integrally rotated.

At the end of the front lateral transmission case 15, a rotation restricting portion 41 that regulates the range of the rotational operation of the upper connecting body 23 is formed. The upward projecting portion 42 formed on the upper connecting body 23 is configured to allow rotation within the range set by the rotation restricting portion 41.

By operating the steering cylinder 27, the upper connecting body 23, that is, the vertical transmission case 19 and the front wheel 3 can be rotated within the operating range regulated by the rotation restricting unit 41. The rotation operation angle of the upper connecting body 23 is detected by the rotation angle detection device 35, and is fed back to a control device (not shown) to control the steering cylinder 27 so as to have a turning angle corresponding to the operation of the steering handle 10. ..

[Vehicle height adjustment mechanism]
Each of the vertical transmission shaft 20 and the vertical transmission case 19 is configured to have an internal / external double structure that can be expanded and contracted while sliding in the axial direction of the vertical transmission shaft 20. As shown in FIGS. 7, 8 and 9, the vertical transmission case 19 has an outer cylinder member 19A and an inner cylinder member 19B, and is configured so that they can expand and contract while sliding. The vertical transmission case 19 is provided with the outer cylinder member 19A located on the lower side and the inner cylinder member 19B located on the upper side, and the lower end portion of the outer cylinder member 19A is integrally connected to the wheel support case 24. , The upper end of the inner cylinder member 19B is integrally connected to the upper connecting body 23.

As shown in FIGS. 7, 8 and 9, the vertical transmission shaft 20 is slidable in the axial direction while maintaining a state in which the vertical transmission shaft 20 is spline-fitted inside the cylinder shaft 20A and integrally rotates. It has a shaft 20B. The upper end of the inner shaft 20B is integrally rotatably connected to the upper bevel gear mechanism 21. The lower end of the cylinder shaft 20A is integrally rotatably connected to the lower bevel gear mechanism 22.

A hydraulically operated type that can switch the relative height of the front wheel 3 to the vehicle body frame F in multiple stages by expanding and contracting the vertical transmission shaft 20 and the vertical transmission case 19 in the direction of the rotation axis Y of the vertical transmission shaft 20. The vehicle height adjusting mechanism 43 is provided. As shown in FIGS. 3, 7, 8 and 9, the vehicle height adjusting mechanism 43 includes a plurality of hydraulic cylinders 44 extending along the axis direction of the vertical transmission shaft 20 and a base member for supporting the plurality of hydraulic cylinders 44. 45 is provided. The plurality of hydraulic cylinders 44 are arranged at different positions in the circumferential direction on the outer peripheral side of the vertical transmission case 19 and at positions facing each other with the vertical transmission case 19 interposed therebetween.

To add a description, as a plurality of hydraulic cylinders 44, two upper hydraulic cylinders 44a that can be extended upward with respect to the base member 45 and 2 that can be extended downward with respect to the base member 45. A lower hydraulic cylinder 44b is provided. The two upper hydraulic cylinders 44a are arranged at different positions in the circumferential direction on the outer peripheral side of the vertical transmission case 19 and at positions facing each other with the vertical transmission case 19 interposed therebetween. Similarly, the two lower hydraulic cylinders 44b are arranged at different positions in the circumferential direction on the outer peripheral side of the vertical transmission case 19 and at positions facing each other across the vertical transmission case 19.

The upper hydraulic cylinder 44a and the lower hydraulic cylinder 44b are arranged at different positions in the circumferential direction. That is, as shown in FIG. 10, the lower hydraulic cylinder 44b is located at a substantially intermediate portion in the circumferential direction of the two upper hydraulic cylinders 44a in the axial direction.

The upper hydraulic cylinder 44a is provided with the piston rod 46 located on the upper side and the cylinder tube 47 located on the lower side, and the lower hydraulic cylinder 44b has the piston rod 48 located on the lower side and the cylinder tube 49. It is provided in a state of being located on the upper side. The tips of the piston rods 46 of the two upper hydraulic cylinders 44a are integrally connected to the upper connecting body 23, and the tips of the piston rods 48 of the two lower hydraulic cylinders 44b are integrally connected to the wheel support case 24. It is connected. The cylinder tube 47 of the two upper hydraulic cylinders 44a and the cylinder tube 49 of the two lower hydraulic cylinders 44b are integrally connected to the base member 45. Therefore, the upper hydraulic cylinder 44a is located on the upper side with respect to the base member 45, and the lower hydraulic cylinder 44b is located on the lower side with respect to the base member 45.

The upper end of the vertical transmission case 19 and the upper ends of the two upper hydraulic cylinders 44a are integrally connected to the upper connecting body 23, and the lower ends of the two lower hydraulic cylinders 44b are integrally connected to the wheel support case 24. Has been done. Further, the cylinder tube 47 of the two upper hydraulic cylinders 44a and the cylinder tube 49 of the two lower hydraulic cylinders 44b are integrally connected to the base member 45. Therefore, the upper connecting body 23 and the wheel support case 24 are integrally connected via the four hydraulic cylinders 44 and the base member 45, and when the steering cylinder 27 operates, those members rotate integrally. Then, the front wheel 3 is turned.

By extending the four hydraulic cylinders 44, as shown in FIG. 7, in the state where the vertical transmission case 19 is most extended, the outer peripheral side of the overlapping portion 50 where the outer cylinder member 19A and the inner cylinder member 19B overlap is the base member. Supported by 45. In this way, even when the vertical width of the polymerization portion 50 is narrow due to the extension of the vertical transmission case 19, the outer peripheral side is supported by the base member 45 to prevent a decrease in the support strength.

As shown in FIGS. 7, 8 and 9, a support boss portion 51 that rotatably supports the inside of the vertical transmission case 19 at the end of the horizontal transmission case 15 to which the upper connecting body 23 is rotatably connected. Is located on the radial inward side of the vertical transmission case 19 and is provided so as to extend downward along the rotation axis Y direction. That is, at the end of the lateral transmission case 15, the support boss portion 51 that rotatably supports the inner peripheral side of the upper connecting body 23 via the bearing 52 is integrated along the axial direction of the vertical transmission shaft 20. It is extended and formed so as to extend downward. The support boss portion 51 rotatably supports the vertical transmission shaft 20 located on the inner peripheral side via the bearing 53.

The support boss portion 51 is provided in a state of extending downward long to the lower side from the intermediate portion in the vertical direction of the inner cylinder member 19B. By supporting the vertical transmission case 19 from the inner peripheral side by the support boss portion 51 that is long in the vertical direction in this way, the support strength of the vertical transmission case 19 is prevented from being lowered.

A communication oil passage 56 for connecting the oil chamber 54 of the upper hydraulic cylinder 44a and the oil chamber 55 of the lower hydraulic cylinder 44b is formed in the vehicle height adjusting mechanism 43 with the inside of the base member 45 inserted. Then, in a state where the communication oil passage 56 is switched to the closed state, hydraulic oil is supplied to the oil chamber 54 of the upper hydraulic cylinder 44a to extend the upper hydraulic cylinder 44a, and then the communication oil passage 56 is opened. The oil chamber 54 and the lower hydraulic cylinder 44b of the upper hydraulic cylinder 44a are switched between the sequential operation mode in which the hydraulic oil is supplied to the oil chamber 55 of the lower hydraulic cylinder 44b and the communication oil passage 56 is switched to the open state. It is configured to be switchable to a simultaneous operation mode in which hydraulic oil is simultaneously supplied to the oil chamber 55.

To add a description, as shown in FIGS. 7, 8 and 9, an internal oil passage 57 extending along the axis direction inside the shaft of the piston rod 46 of the upper hydraulic cylinder 44a integrally connected to the upper connecting body 23. Is formed. The hydraulic oil supply port 58 is formed in the upper connecting body 23, and the hydraulic oil supply port 58 is communicated with the internal oil passage 57. Although not shown, hydraulic oil is supplied to the hydraulic oil supply port 58 from the hydraulic pump provided in the traveling vehicle body 1 via the hydraulic control valve. Since the internal oil passage 57 is formed inside the shaft of the piston rod 46 in this way, the hydraulic oil can be supplied into the oil chamber by using the internal oil passage 57, and the hydraulic oil supply port 58 is special. It is not necessary to provide external piping, etc., and the hydraulic piping can be simplified.

As shown in FIG. 11, at the upper and lower intermediate positions of the base member 45, the oil chamber 54 inside the cylinder tube 47 of the upper hydraulic cylinder 44a and the oil chamber 55 inside the cylinder tube 49 of the lower hydraulic cylinder 44b communicate with each other. The communication oil passage 56 is integrally formed with the base member 45. An electromagnetically operated on-off valve 59 is provided in the middle of the communication passage 56.

As shown in FIG. 9, from the shortest state in which all four hydraulic cylinders 44 are retracted, the on-off valve 59 is switched to the closed state to shut off the communication oil passage 56 and operate on the two upper hydraulic cylinders 44a. Hydraulic oil is supplied from the oil supply port 58. Then, only the two upper hydraulic cylinders 44a are switched to the extended state, and the two lower hydraulic cylinders 44b are in the intermediate extended state in which the degenerate state is maintained (see FIG. 8).

Next, when the on-off valve 59 is opened to further supply hydraulic oil from the hydraulic oil supply port 58, the cylinder of the lower hydraulic cylinder 44b is further supplied from the oil chamber 54 of the cylinder tube 47 of the upper hydraulic cylinder 44a through the communication oil passage 56. Hydraulic oil is supplied to the oil chamber 55 of the tube 49. Then, the two upper hydraulic cylinders 44a and the two lower hydraulic cylinders 44b each reach the maximum extended state in which the extended state is switched (see FIG. 7). The operation mode in which the shortest state is switched to the maximum extension state via the intermediate extension state in this way is the sequential operation mode. Therefore, in the sequential operation mode, the ground clearance (vehicle height) of the traveling vehicle body 1 can be switched to three stages of a low position (shortest state), an intermediate position (intermediate extension state), and a high position (maximum extension state).

As shown in FIG. 9, from the shortest state in which all four hydraulic cylinders 44 are retracted, the on-off valve 59 is switched to the open state to open the communication oil passage 56 and operate on the two upper hydraulic cylinders 44a. When the hydraulic oil is supplied from the oil supply port 58, the hydraulic oil is supplied through the internal oil passage 57 and the communication oil passage 56, and the two upper hydraulic cylinders 44a and the two lower hydraulic cylinders 44b are in the extended state at the same time. Then, it switches to the maximum extension state (see FIG. 7). The operation mode for switching from the shortest state to the maximum extension state is the simultaneous operation mode. Therefore, in the simultaneous operation mode, the ground clearance (vehicle height) of the traveling vehicle body 1 can be switched between two stages: a low position (shortest state) and a high position (maximum extension state).

Although not shown, switching between the sequential operation mode and the simultaneous operation mode is performed by the mode switching operation tool provided in the driver unit 6, and the vehicle height change operation is performed by the vehicle height switching operation tool provided in the driver unit 6. The control device (not shown) controls the operation so as to switch the hydraulic control valve and the on-off valve 59 to the corresponding states according to the operation of the mode switching operation tool and the vehicle height switching operation tool. .. The configuration is not limited to each of the sequential operation mode and the simultaneous operation mode, and may be a configuration including either mode.

As shown in FIG. 3, a stroke sensor as an operation amount detecting means is located inward in the vehicle body width direction in the vertical transmission case 19 and extends vertically along the extending direction of the vertical transmission case 19. 60 is provided. The stroke sensor 60 is provided over the upper connecting body 23 and the support bracket 61 provided at the lower part of the wheel support case 24.

As shown in FIG. 12, an outer cylinder 62 as a first member that moves relative to each other as the four hydraulic cylinders 44 expand and contract, and an inner cylinder as a second member that is slidably fitted in the outer cylinder 62. In addition to the 63, a cylindrical sliding member 64 having a cylinder structure is provided in which the outer cylinder 62 and the end portion of the inner cylinder 63 facing the outside are closed to form a closed space inside. In the tubular sliding member 64, the upper end portion of the outer cylinder 62 is connected to the upper connecting body 23, and the lower end portion of the inner cylinder 63 is connected to the support bracket 61.

As shown in FIG. 12, the stroke sensor 60 is housed inside the cylindrical sliding member 64. The stroke sensor 60 is provided in a state of being integrally moved to the outer cylinder 62 and is provided on the screw shaft 66 in which the spiral blade 65 is integrally formed on the outer peripheral portion, and is provided on the inner cylinder 63 and is provided on the inner cylinder 63 and the outer cylinder 63. A sliding contact member 67 that slides on the spiral blade 65 to guide the screw shaft 66 to rotate as it moves relative to the cylinder 62, and an electromagnetic wave as a rotation detection sensor that can detect the rotation speed of the screw shaft 66. It has a pickup sensor 68 of the type.

The screw shaft 66 is supported by a support portion 69 provided at the upper end of the outer cylinder 62 in a state of being integrally moved along the axis direction and rotatably supported in the circumferential direction. The screw shaft 66 extends along the inside of the inner cylinder 63. The upper end of the inner cylinder 63 is provided with a sliding contact member 67 that is extrapolated to the screw shaft 66 and has a sliding contact action with the spiral blade 65. A detection gear 70 is provided at a position extending above the sliding contact member 67 on the screw shaft 66. The outer cylinder 62 is provided with an electromagnetic pickup sensor 68 having a well-known configuration at a location corresponding to the outer peripheral portion of the detection gear 70. The pickup sensor 68 is widely used in, for example, agricultural machinery and other devices, and can accurately detect the rotation speed.

When the outer cylinder 62 and the inner cylinder 63 move relative to each other in the axial direction as the four hydraulic cylinders 44 expand and contract, the spiral blade 65 of the screw shaft 66 receives the sliding contact action of the sliding contact member 67, and the amount of movement is increased. The screw shaft 66 rotates by the amount of rotation corresponding to. The pickup sensor 68 can detect the rotation speed of the screw shaft 66 based on the waveform of the current generated when the teeth of the detection gear 70 accompanying the rotation of the screw shaft 66 pass. Then, by counting the number of rotations of the screw shaft 66 from the start of rotation to the stop, the amount of movement of the screw shaft 66 in the axis direction (the amount of expansion / contraction operation accompanying the expansion / contraction operation of the four hydraulic cylinders 44) is calculated. You can ask.

[Another Embodiment]
(1) In the above embodiment, the vehicle height adjusting mechanism 43 is provided with two upper hydraulic cylinders 44a and two lower hydraulic cylinders 44b as a plurality of hydraulic cylinders extending along the axis direction. Instead of this configuration, three or more upper hydraulic cylinders 44a and lower hydraulic cylinders 44b may be provided, or a plurality (two or more) of hydraulic cylinders long in the vertical direction along the axis direction may be provided. It may be configured. Further, instead of the above configuration, the vehicle height adjusting mechanism 43 may be provided with one hydraulic cylinder, and various expansion / contraction operation devices such as an electric cylinder and a pneumatic cylinder can be used instead of the hydraulic cylinder.

(2) In the above embodiment, the overlapping portion 50 in which the outer cylinder member 19A and the inner cylinder member 19B overlap each other in a state where the base member 45 for supporting the plurality of hydraulic cylinders 44 is provided and the vertical transmission case 19 is most extended. Although the outer peripheral side of the cylinder is supported by the base member 45, instead of this configuration, a dedicated support member for supporting the overlapping portion 50 of the vertical transmission case 19 may be provided in addition to the base member 45.

(3) In the above embodiment, the horizontal transmission case 15 is provided with a support boss portion 51 that rotatably supports the inside of the vertical transmission case 19, but instead of this configuration, the vertical transmission case is provided. The rigidity of the 19 itself may be increased so that the support boss portion 51 is not provided.

(4) In the above embodiment, the screw shaft 66 can be integrally moved in the axial direction and can be rotated in the circumferential direction at the upper end of the outer cylinder 62 of the cylindrical sliding member 64 accommodating the stroke sensor 60. A support portion 69 is provided to support the screw shaft 66, and the detection gear 70 is provided at a position extending above the sliding contact member 67 in the screw shaft 66. However, the following configuration may be used instead of this configuration. good.
As shown in FIG. 13, the screw shaft 66 extends outward from the support portion 69, the detection gear 70 is provided at the extended portion, and the pickup sensor 68 is provided at the corresponding portion. May be good. With this configuration, maintenance processing of the detection gear 70 and the pickup sensor 68 can be easily performed.

(5) In the above embodiment, a control device for operating and controlling the hydraulic control valve and the on-off valve, a stroke sensor, and the like are provided, and the vehicle height change operation is executed based on the detection result of the stroke sensor 60. The configuration is such that the operation of the vehicle height adjustment mechanism 43 is controlled, but instead of the configuration for executing such complicated control, the upper hydraulic cylinder 44a and the two lower parts are based on a manual command without providing a stroke sensor. It is also possible to have a simple hydraulic control configuration in which the side hydraulic cylinder 44b is simply switched between the hydraulic oil supply state and the oil drainage state.

(6) In the above embodiment, the chemical spraying device 2 is provided as a working device, but the working device may be provided with a fertilizer application device or another type of working device.

The present invention can be applied to a passenger-type work vehicle provided with a plurality of traveling wheels.

1 Traveling vehicle body 5 Engine 13,15 Horizontal transmission case 14,18 Horizontal transmission shaft 19 Vertical transmission case 19A Outer cylinder member 19B Inner cylinder member 20 Vertical transmission shaft 43 Vehicle height adjustment mechanism 44 Hydraulic cylinder 45 Base member 50 Polymerization section F Body frame S Running wheels

Claims (4)

The traveling vehicle body is provided with a vehicle body frame, a plurality of traveling wheels, and an engine for driving the plurality of traveling wheels, and the power of the engine is transmitted to the traveling wheels via a lateral transmission shaft and a vertical transmission shaft. A passenger-type work vehicle in which the traveling wheel is supported so as to be reorientable around the rotation axis of the vertical transmission shaft with respect to the vehicle body frame.
Each of the vertical transmission shaft and the vertical transmission case that covers the circumference of the vertical transmission shaft is configured to have an internal / external double structure that can be expanded and contracted while sliding in the axial direction of the vertical transmission shaft.
The vertical transmission case is rotatably supported around the rotation axis of the vertical transmission shaft with respect to the vehicle body side case supported by the vehicle body frame integrally with the traveling wheel.
A vehicle height adjustment mechanism capable of switching the relative height of the traveling wheel with respect to the vehicle body frame in a plurality of stages by expanding and contracting the vertical transmission shaft and the vertical transmission case in the axial direction is provided .
The vehicle height adjusting mechanism includes, as a plurality of hydraulic cylinders extending along the axis direction, an upper hydraulic cylinder that can be extended toward the upper side and a lower hydraulic cylinder that can be extended toward the lower side. Be prepared,
The vehicle height adjustment mechanism is in the shortest state in which the upper hydraulic cylinder and the lower hydraulic cylinder are retracted, and one of the upper hydraulic cylinder and the lower hydraulic cylinder is retracted and the other is extended. A passenger type that can be switched between three states: an extended state and a maximum extended state in which the upper hydraulic cylinder and the lower hydraulic cylinder are extended, and the relative height can be switched in three stages. Work vehicle. The vehicle height adjusting mechanism is provided with a base member that supports the plurality of hydraulic cylinders.
The vertical transmission case is
As an inner / outer double structure, the inner cylinder member and the outer cylinder member can expand and contract while sliding, and in the most extended state, the outer peripheral side of the overlapping portion where the inner cylinder member and the outer cylinder member overlap is the said. The passenger-type work vehicle according to claim 1, which is supported by a base member. The traveling vehicle body is provided with a vehicle body frame, a plurality of traveling wheels, and an engine for driving the plurality of traveling wheels, and the power of the engine is transmitted to the traveling wheels via a lateral transmission shaft and a vertical transmission shaft. A passenger-type work vehicle in which the traveling wheel is supported so as to be reorientable around the rotation axis of the vertical transmission shaft with respect to the vehicle body frame.
Each of the vertical transmission shaft and the vertical transmission case that covers the circumference of the vertical transmission shaft is configured to have an internal / external double structure that can be expanded and contracted while sliding in the axial direction of the vertical transmission shaft.
The vertical transmission case is rotatably supported around the rotation axis of the vertical transmission shaft with respect to the vehicle body side case supported by the vehicle body frame integrally with the traveling wheel.
A vehicle height adjustment mechanism capable of switching the relative height of the traveling wheel with respect to the vehicle body frame in a plurality of stages by expanding and contracting the vertical transmission shaft and the vertical transmission case in the axial direction is provided.
The vehicle height adjusting mechanism is provided with a plurality of hydraulic cylinders extending along the axis direction and a base member for supporting the plurality of hydraulic cylinders.
The vertical transmission case is
As an inner / outer double structure, the inner cylinder member and the outer cylinder member can expand and contract while sliding, and in the most extended state, the outer peripheral side of the overlapping portion where the inner cylinder member and the outer cylinder member overlap is the said. A passenger-type work vehicle supported by a base member. The vehicle body side case is provided with a support boss portion that rotatably supports the vertical transmission case.
The aspect according to any one of claims 1 to 3, wherein the support boss portion is located on the radial inward side of the vertical transmission case and is provided so as to extend downward along the axis direction. Passenger type work vehicle.

Images