JP6899802B2 - Passenger work vehicle - Google Patents

Description

According to the present invention, a traveling vehicle body is provided with a vehicle body frame and a plurality of traveling wheels, and the traveling wheels are supported by the vehicle body frame via a tubular support member extending in the vertical direction. Regarding.

In this type of passenger-type work vehicle, conventionally, a vertical transmission shaft and a vertical case as a tubular support member covering the vertical transmission shaft are provided long in the vertical direction to increase the ground height of the traveling vehicle body. Some of them have a high clearance specification, and the vertical length of the vertical 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 clearance of the traveling vehicle body so that the vehicle body does not come into contact with the ridges formed in the field or the planted crops.

Japanese Unexamined Patent Publication No. 2003-94907 Japanese Unexamined Patent Publication No. 7-195902

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 is excessive or insufficient due to the difference in the growing condition and type of crops or the difference in working conditions. It was. 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, the ground clearance of the traveling vehicle body may be too high and the posture may become unstable.

By the way, as a configuration for changing the ground clearance of the traveling vehicle body, the mounting position of the wheel support case that supports the rotating shaft of the traveling wheel is changed in the vertical transmission case as a tubular support member that supports the traveling wheel. A configuration has been proposed in which the ground clearance of the traveling vehicle body can be changed (see, for example, Patent Document 2). Specifically, the wheel support case is attached in a state where the rotation axis of the traveling wheel is eccentric with respect to the output shaft of the vertical transmission case and the position can be changed by rotating around the axis of the output shaft. By changing the rotation position of the wheel support case and fixing the position with bolts, the ground height of the traveling vehicle body is changed.

However, in such a configuration in which the mounting position of the wheel support case is changed, the sliding resistance between the vertical transmission case and the wheel support case becomes large, and there is a risk that the wheel support case cannot be smoothly rotated. Therefore, troublesome work such as fixing work with bolts was required. Furthermore, the amount of adjustment that can change the ground clearance of the traveling vehicle body is not sufficient, and there is a disadvantage that it is not easy to use.

Therefore, it is possible to set the ground clearance of the traveling vehicle body to the optimum height according to the growing condition of the crop, the type of the crop, the difference in the working condition, etc., without any troublesome work. It was desired.

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 and a plurality of traveling wheels, and the traveling wheels extend in the vertical direction via a tubular support member. The support member is configured to be expandable and contractible in the vertical direction, and the relative height of the traveling wheel with respect to the vehicle body frame can be switched in a plurality of stages by expanding and contracting the support member. A hydraulically operated vehicle height adjusting mechanism is provided, and the vehicle height adjusting mechanism is provided with a plurality of hydraulic cylinders that can be expanded and contracted along the expansion and contraction direction of the support member. The wheels are arranged at different positions in the circumferential direction on the outer peripheral side of the wheel and at positions facing each other across the support member, and are located at locations corresponding to the intermediate portion of the support member in the vertical direction in the vehicle height adjustment mechanism. A base member for supporting one end of the plurality of hydraulic cylinders is provided, and the support member includes an outer cylinder member and an inner cylinder member inserted into the outer cylinder member, and the outer cylinder member and the said support member. The inner cylinder member expands and contracts by relatively moving in the axial direction, and when the support member is most extended, 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. It is in the point that it is done.

According to this configuration, when the support member is expanded and contracted in the vertical direction by a vehicle height adjusting mechanism including a plurality of hydraulic cylinders, the relative height of the traveling wheel with respect to the vehicle body frame can be switched in a plurality of stages. Since the plurality of hydraulic cylinders are arranged at different positions in the circumferential direction on the outer peripheral side of the support member and at positions facing each other across the support member, the support member receives an operating force evenly by the plurality of hydraulic cylinders. Therefore, the support member can be smoothly expanded and contracted without any disadvantage such as an unbalanced load being applied. Moreover, since the hydraulic cylinder can be expanded and contracted, there is no need for manual connection work for fixing the position, and there is no need for troublesome work.

Therefore, it is possible to set the ground clearance of the traveling vehicle body to the optimum height according to the growing condition of the crop, the type of the crop, the difference in the working condition, etc., without any troublesome work. It has become 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 and a plurality of traveling wheels, and the traveling wheels are provided with a tubular support member extending in the vertical direction. It is supported by the vehicle body frame, and the support member is configured to be expandable and contractible in the vertical direction, and the support member is expanded and contracted to switch the relative height of the traveling wheel with respect to the vehicle body frame in a plurality of stages. A possible hydraulically operated vehicle height adjusting mechanism is provided, and the vehicle height adjusting mechanism is provided with a plurality of hydraulic cylinders that can be expanded and contracted along the expansion and contraction direction of the support member. It is located on the outer peripheral side of the support member at different positions in the circumferential direction and at positions facing each other across the support member, and is located at a position corresponding to the intermediate portion of the support member in the vertical direction in the vehicle height adjustment mechanism. A base member that supports the plurality of hydraulic cylinders is provided, and as the plurality of hydraulic cylinders, an upper hydraulic cylinder that can be extended upward with respect to the base member and a lower hydraulic cylinder that can be extended downward with respect to the base member. It provided an elongate operable lower hydraulic cylinder toward the side, and the upper hydraulic cylinder and the lower hydraulic cylinder is in a point that is located at different positions in the circumferential direction.

According to this configuration, when the upper hydraulic cylinder expands and contracts, the area above the base member expands and contracts, and when the lower hydraulic cylinder expands and contracts, the area below the base member expands and contracts. When both the upper hydraulic cylinder and the lower hydraulic cylinder are extended, the entire vehicle height adjustment mechanism can be switched to the longest state that is long in the vertical direction. When both the upper hydraulic cylinder and the lower hydraulic cylinder are degenerated, the entire vehicle height adjustment mechanism can be switched to the shortest state short in the vertical direction. Then, when either one of the upper hydraulic cylinder or the lower hydraulic cylinder is extended and the other is degenerated, the entire vehicle height adjustment mechanism can be switched to an intermediate length state located between the shortest state and the longest state. ..

With this configuration, it is possible to increase the expansion / contraction adjustment amount of the entire vehicle height adjustment mechanism while using small hydraulic cylinders having a short expansion / contraction operation amount. Moreover, by selecting a state in which the hydraulic oil is supplied to a maximum state and a state in which the hydraulic oil is discharged to a plurality of hydraulic cylinders, a state in which the hydraulic oil is supplied without performing special position control. With a simple hydraulic supply configuration that switches to a state in which hydraulic oil is discharged, the vehicle height adjustment mechanism can be switched to three stages: a shortest state, an intermediate length state, and a longest state.

In the present invention, the vehicle height adjusting mechanism is provided with a communication oil passage connecting the oil chamber of the upper hydraulic cylinder and the oil chamber of the lower hydraulic cylinder, and the communication oil passage is switched to a closed state. After the hydraulic oil is supplied to the oil chamber of the upper hydraulic cylinder to extend the upper hydraulic cylinder, the communication oil passage is switched to the open state and the hydraulic oil is supplied to the oil chamber of the lower hydraulic cylinder. It is possible to switch between a sequential operation mode in which hydraulic oil is supplied and a simultaneous operation mode in which hydraulic oil is simultaneously supplied to the oil chamber of the upper hydraulic cylinder and the oil chamber of the lower hydraulic cylinder while the communication oil passage is switched to the open state. It is preferable that it is configured in.

According to this configuration, when the hydraulic oil is supplied to the upper hydraulic cylinder from the hydraulic oil supply source, the hydraulic oil can be supplied not only to the upper hydraulic cylinder but also to the lower hydraulic cylinder through the communication oil passage. Then, by switching the open / closed state of the communication oil passage, the upper hydraulic cylinder and the lower hydraulic cylinder are operated in sequence, or the upper hydraulic cylinder and the lower hydraulic cylinder are operated at the same time. It is possible to use it properly depending on the difference, and the usability is improved.

In the present invention, it is preferable that the communication oil passage is formed so as to penetrate the inside of the base member.

According to this configuration, the communication oil passage is formed inside the base member, and it is not necessary to provide a special hydraulic pipe so as to bypass the outside. It is possible to operate the vehicle height adjustment mechanism satisfactorily without any disadvantage such as a decrease in durability of the vehicle.

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.

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 vehicle body 1. This work vehicle sprays chemicals on crops while traveling across the crop planting strips in fields where crops have already been planted.

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 transmission 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 wheels 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 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 and a speed change lever 12 for raising and lowering the working device.

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 tubular rear lateral transmission case 13 (an example of a vehicle body side case) connected to both the left and right sides of the mission case 7, and the power after shifting is laterally transmitted. 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 tubular 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 rotatably supported 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 as a support member is connected to both left and right ends of the front horizontal 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 reorientably oriented 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 in a front view 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. It is movably fitted and connected. As shown in FIG. 7, a wheel support case 24 for covering the lower bevel gear mechanism 22 and supporting the rotating shaft 3a of the front wheel 3 is connected to the lower end portion of the vertical transmission case 19.

A retaining tool 25 for preventing the upper connecting body 23 from coming off while being fitted and connected is provided. As shown in FIG. 5, the retaining tool 25 is made of a strip-shaped member, one end of which is bolted to the outer peripheral portion of the upper connecting body 23, and the other end of which is connected to the end 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 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 slid to the left or right from the neutral position for straight running by hydraulic pressure.

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 above the end portion of the front lateral transmission case 15. The rotation angle detection device 35 includes a potentiometer-type detection 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 operating arm 37 is bolted to the outer peripheral portion of the upper connecting body 23, and the other end 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 operating arm 37 is provided so as to extend obliquely upward from the connection portion 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 rotation 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 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 tubular 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 wheels 3 to the vehicle body frame F in a plurality of 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 of the above 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 axial 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 two upper hydraulic cylinders 44a that can be extended downward with respect to the base member 45. Two lower hydraulic cylinders 44b are 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 located on the lower side. 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.

As shown in FIG. 7, when the four hydraulic cylinders 44 are extended, the outer peripheral side of the overlapping portion 50 on which the inner cylinder member 19A and the outer cylinder member 19B overlap is the base member in the state where the vertical transmission case 19 is most extended. Supported by 45. In this way, even when the vertical width of the overlapping 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 supporting 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 lateral 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 downwardly from the intermediate portion in the vertical direction of the inner cylinder member 19B to the lower side. 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, it is possible to prevent a decrease in the support strength of the vertical transmission case 19.

A communication oil passage 56 is formed in the vehicle height adjusting mechanism 43 to connect the oil chamber 54 of the upper hydraulic cylinder 44a and the oil chamber 55 of the lower hydraulic cylinder 44b while inserting the inside of the base member 45. Then, while 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. A sequential operation mode in which hydraulic oil is supplied to the oil chamber 55 of the lower hydraulic cylinder 44b by switching, and an oil chamber 54 and the lower hydraulic cylinder 44b of the upper hydraulic cylinder 44a in a state where 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. A 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 or the like, 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 oil passage 56.

As shown in FIG. 9, from the shortest state in which all four hydraulic cylinders 44 are degenerated, 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. The 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 are each in the maximum extended state in which the extended state is switched to the extended state (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 the two upper hydraulic cylinders 44a are operated. 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 of the hydraulic control valve and the on-off valve 59 so as to switch 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 the configuration including the sequential operation mode and the simultaneous operation mode, respectively, and may be a configuration including either one of the modes.

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 tubular sliding member 64. The stroke sensor 60 is provided on a screw shaft 66 that is integrally moved to the outer cylinder 62 and has a spiral blade 65 integrally formed on the outer peripheral portion, and is provided on the inner cylinder 63 and is provided on the inner cylinder 63 and outside. A sliding contact member 67 that acts in sliding contact with the spiral blade 65 to guide the screw shaft 66 to rotate as it moves relative to the cylinder 62, and electromagnetic waves as a rotation detection sensor capable of detecting 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 portion 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 slides into contact with the spiral blade 65. A detection gear 70 is provided on the screw shaft 66 at a position extending upward from the sliding contact member 67. 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 that accompany 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 axial core direction (the amount of expansion / contraction operation accompanying the expansion / contraction operation of the four hydraulic cylinders 44) You can ask.

[Another Embodiment]
(1) In the above embodiment, the vertical transmission case 19 as a support member is provided with the vertical transmission shaft 20 inside, and the vertical transmission case 19 and the vertical transmission shaft 20 are respectively provided with the vertical transmission shaft 20. Although the structure is shown to have an internal / external double structure that can be expanded and contracted while sliding in the axial direction of the shaft, instead of this configuration, the vertical transmission case 19 is not provided with a transmission shaft. May be. That is, the traveling wheel is in a state of freely rotating in a non-driving state.

(2) 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 and they may be evenly distributed in the circumferential direction, or in the vertical direction along the axis direction. A plurality of (two or more) long hydraulic cylinders may be provided, and these may be evenly distributed and arranged in the circumferential direction.

(3) In the above embodiment, the vehicle height adjusting mechanism 43 is configured to be switchable between the sequential operation mode and the simultaneous operation mode, but instead of such a configuration, the vehicle height adjustment mechanism 43 is simultaneously operated with the sequential operation mode. It may be configured to execute only one of the modes.

(4) In the above embodiment, the communication oil passage is formed in a state where the inside of the base member is inserted, but instead of this configuration, the communication oil passage may be configured by a hose or an external pipe. Further, without providing such a communication oil passage, the upper hydraulic cylinder 44a and the two lower hydraulic cylinders 44b may be provided with separate pipes for supplying hydraulic oil.

(5) 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 tubular sliding member 64 accommodating the stroke sensor 60. A support portion 69 for supporting is provided, and a detection gear 70 is provided at a position extending above the sliding contact member 67 on the screw shaft 66. Instead of this configuration, the screw shaft 66 is configured as follows. May be 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 extending 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.

(6) In the above embodiment, the control device for operating and controlling the hydraulic control valve and the on-off valve, the stroke sensor 60, and the like are provided, and the vehicle height change operation is executed based on the detection result of the stroke sensor 60. Although the configuration is such that the operation of the vehicle height adjusting mechanism 43 is controlled, instead of the configuration for executing such complicated control, the upper hydraulic cylinders 44a and 2 are based on a manual command without providing the stroke sensor 60. The two lower hydraulic cylinders 44b may have a simple hydraulic circuit configuration that simply switches between the hydraulic oil supply state and the oil drainage state.

(7) In the above embodiment, the overlapping portion 50 in which the inner cylinder member 19A and the outer cylinder member 19B overlap each other when 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.

(8) 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.

(9) In the above embodiment, the chemical spraying device 2 is provided as the 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 19 Support member (vertical transmission case)
43 Vehicle height adjustment mechanism 44 Hydraulic cylinder 44a Upper hydraulic cylinder 44b Lower hydraulic cylinder 45 Base member 54,55 Oil chamber 56 Communication oil passage

Claims (4)

The traveling vehicle body is provided with a vehicle body frame and a plurality of traveling wheels.
A passenger-type work vehicle in which the traveling wheels are supported by the vehicle body frame via a tubular support member extending in the vertical direction.
The support member is configured to be expandable and contractible in the vertical direction.
A hydraulically operated 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 support member is provided.
The vehicle height adjusting mechanism is provided with a plurality of hydraulic cylinders that can be expanded and contracted along the expansion and contraction direction of the support member.
The plurality of hydraulic cylinders are arranged at different positions in the circumferential direction on the outer peripheral side of the support member and at positions facing each other with the support member interposed therebetween .
The vehicle height adjusting mechanism is provided with a base member that is located at a position corresponding to an intermediate portion in the vertical direction of the support member and supports one end of the plurality of hydraulic cylinders.
The support member includes an outer cylinder member and an inner cylinder member inserted into the outer cylinder member, and the outer cylinder member and the inner cylinder member expand and contract by relatively moving in the axial direction.
A passenger-type work vehicle in which the outer peripheral side of the overlapping portion where the inner cylinder member and the outer cylinder member overlap when the support member is most extended is supported by the base member. The traveling vehicle body is provided with a vehicle body frame and a plurality of traveling wheels.
A passenger-type work vehicle in which the traveling wheels are supported by the vehicle body frame via a tubular support member extending in the vertical direction.
The support member is configured to be expandable and contractible in the vertical direction.
A hydraulically operated 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 support member is provided.
The vehicle height adjusting mechanism is provided with a plurality of hydraulic cylinders that can be expanded and contracted along the expansion and contraction direction of the support member.
The plurality of hydraulic cylinders are arranged at different positions in the circumferential direction on the outer peripheral side of the support member and at positions facing each other with the support member interposed therebetween.
The vehicle height adjusting mechanism is provided with a base member that supports the plurality of hydraulic cylinders at a position corresponding to an intermediate portion in the vertical direction of the support member.
The plurality of hydraulic cylinders include an upper hydraulic cylinder that can be extended upward with respect to the base member and a lower hydraulic cylinder that can be extended downward with respect to the base member. ,
It said upper hydraulic cylinder and the lower hydraulic cylinder and is riding mold work vehicle that is arranged at different positions in the circumferential direction. The vehicle height adjustment mechanism
A communication oil passage for connecting the oil chamber of the upper hydraulic cylinder and the oil chamber of the lower hydraulic cylinder is provided.
After the hydraulic oil is supplied to the oil chamber of the upper hydraulic cylinder to extend the upper hydraulic cylinder while the communication oil passage is switched to the closed state, the communication oil passage is switched to the open state and described. Sequential operation mode that supplies hydraulic oil to the oil chamber of the lower hydraulic cylinder, and
A claim configured to be switchable between a simultaneous operation mode in which hydraulic oil is simultaneously supplied to the oil chamber of the upper hydraulic cylinder and the oil chamber of the lower hydraulic cylinder while the communication oil passage is switched to the open state. The passenger type work vehicle according to Item 2. The passenger-type work vehicle according to claim 3, wherein the communication oil passage is formed so as to pass through the inside of the base member.

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