JP2021088208A - Work vehicle - Google Patents

Abstract

To prevent a twisting manipulation force from being applied to a vehicle height adjustment cylinder, and make it possible to steer traveling wheels.SOLUTION: A traveling wheel 1 is borne by a lower part of a longways transmission case 14 extending downward from each of ends of a sideways transmission case 13. The longways transmission case 14 includes an upper case part 14A linked to a steering mechanism 40, and a lower case part 14B slidably engaged with the upper case part 14A. A vehicle height adjustment cylinder is included to adjust, that is, stretch or contract the longways transmission case 14. A keyway is formed in one of the upper case part 14A and the lower case part 14B. A key to be fitted into the keyway is included in the other one of the upper case part 14A and the lower case part 14B. Accordingly, a rotation restriction mechanism is realized to restrict relative rotations of the upper case part 14A and the lower case part 14B.SELECTED DRAWING: Figure 4

Description

The present invention relates to a work vehicle.

The work vehicle is supported by a horizontal transmission case that is supported by the vehicle body in a state of extending in the horizontal direction of the vehicle body, a vertical transmission case that extends downward from both ends of the horizontal transmission case, and a lower portion of the vertical transmission case. Some are equipped with running wheels. Since the vertical transmission case raises the ground height of the horizontal transmission case, it is possible to run across the crop while preventing the crop from touching the horizontal transmission case.

As a work vehicle of this type, for example, there is an agricultural tractor shown in Patent Document 1. The agricultural tractor shown in Patent Document 1 is provided with an axle case as a horizontal transmission case and a vertical axis case as a vertical transmission case.

In this type of work vehicle, the vertical transmission case is configured to be expandable and contractible by an upper case portion and a lower case portion that is slidably fitted to the upper case portion, and is provided in the horizontal orientation inside the horizontal transmission case. The vertical transmission shaft provided inside the vertical transmission case can be expanded and contracted as the vertical transmission case expands and contracts while transmitting the power of the transmission shaft to the traveling wheels. Some are equipped with a vehicle height adjustment cylinder that expands and contracts the vertical transmission case. For example, when it is stored in a barn, it is possible to adjust the vehicle height to be lower than when working.

Japanese Unexamined Patent Publication No. 2003-94907

In a work vehicle having the above-described vehicle height adjustment configuration, a steering mechanism that steers the traveling wheels by rotating the vertical transmission case with respect to the horizontal transmission case with the steering axis as the rotation center. Since the steering mechanism is generally linked to the upper case portion, the steering mechanism is applied to the upper case portion and the ground reaction force is applied to the lower case portion when the steering operation of the traveling wheel is performed. When the upper case portion and the lower case portion rotate relative to each other due to the hooking, a twisting operation force is applied to the vehicle height adjusting cylinder.

According to the present invention, while it is possible to adjust the vehicle height and steer the traveling wheels, the traveling wheels are steered while preventing the vehicle height adjusting cylinder from being twisted and operated by a simple structure preventing means. Provide a work vehicle that can be used.

The work vehicle according to the present invention
A lateral transmission case that is supported by the vehicle body in a state of extending in the lateral width direction of the vehicle body, a vertical transmission case that extends downward from both ends of the horizontal transmission case, and a traveling wheel that is supported by the lower portion of the vertical transmission case. A steering mechanism that steers the traveling wheel by rotating the vertical transmission case around a steering axis substantially parallel to the extending direction of the vertical transmission case, and the lateral transmission. A lateral transmission shaft rotatably provided inside the case and a rotatably provided inside the vertical transmission case are rotatably provided by transmitting the power of the lateral transmission shaft to rotate, and the power is transferred to the traveling wheel. The vertical transmission case is provided with an upper case portion extending downward from the end portion of the lateral transmission case in a state in which the steering mechanism is linked, and the upper case portion. It is composed of a lower case portion that is slidably fitted to the vertical transmission case, and can be expanded and contracted in a direction along the extending direction of the vertical transmission case. A vehicle height adjustment cylinder that is connected to the upper case portion and the lower case portion and adjusts the expansion and contraction of the vertical transmission case is provided, and the steering axis is centered on rotation. A rotation regulating mechanism for regulating the relative rotation between the upper case portion and the lower case portion is provided, and the rotation regulating mechanism is formed on one of the upper case portion and the lower case portion, and the vertical transmission is performed. A key groove extending along the extending direction of the case, and a key provided on the other side of the upper case portion and the lower case portion and movably inserted into the key groove along the extending direction of the vertical transmission case. And have.

According to this configuration, the vehicle height adjustment cylinder expands and contracts the vertical transmission case, and when the vertical transmission case is expanded and contracted, the vertical transmission shaft expands and contracts as the vertical transmission case expands and contracts, and the traveling wheels. Since the mounting height of the cylinder to the sideways transmission case changes, the vehicle height can be adjusted.

The steering mechanism rotates the upper case with the steering axis as the center of rotation with respect to the lateral transmission case, and when the upper case is rotated, the rotational power of the upper case is a rotation regulation mechanism. The lower case portion is rotated by being transmitted to the lower case portion via the above, and the traveling wheel is oscillated by the lower case portion with the steering axis as the swing fulcrum, so that the traveling wheel can be steered. At this time, the relative rotation between the upper case portion and the lower case portion is regulated by the rotation regulation mechanism. The structure of the rotation regulation mechanism can be as simple as providing a keyway and a key. That is, in the case where the vehicle height can be adjusted, the traveling wheels can be steered while preventing the vehicle height adjustment cylinder from being twisted and operated by a simple structure.

In the present invention
It is preferable that the rotation regulating mechanism is provided at a plurality of locations in the circumferential direction of the vertical transmission case.

According to this configuration, since the relative rotation between the upper case portion and the lower case portion is regulated by the rotation regulating mechanisms at a plurality of locations, it is possible to firmly prevent the vehicle height adjusting cylinder from being twisted and operated.

In the present invention
The lateral transmission case is provided with a boss portion that extends downward from the end portion of the lateral transmission case to between the upper case portion and the vertical transmission shaft and supports the upper case portion from the inside. The vertical transmission case is provided with a reinforcing cylinder that is slidably fitted outward along the axis of the vertical transmission shaft, and when the vertical transmission case is extended, the vertical transmission case is said to be said. The reinforcing cylinder extends over a boss-side polymerization portion where the upper case portion and the boss portion overlap, and a lower case portion-side polymerization portion where the upper case portion and the lower case portion of the vertical transmission case overlap. It is preferable that a positioning mechanism for positioning the reinforcing cylinder in the positioned state is provided.

When the vertical transmission case is extended, the boss portion side polymerization portion and the lower case portion side polymerization portion are configured to be located apart from each other in the direction along the axis of the vertical transmission shaft, and the vertical transmission case. The shorter the length of the reinforcing cylinder, which is a member that regulates the shortening of the vertical transmission case, the larger the expansion / contraction stroke of the vertical transmission case. According to this configuration, when the vertical transmission case is extended, the boss portion side polymerization portion and the lower case portion side polymerization portion are configured to be located apart from each other, and the length of the reinforcing cylinder is shortened for transmission. Even if the expansion / contraction stroke of the case is increased, when the vertical transmission case is extended, the reinforcing cylinder is positioned over the boss side polymerization part and the lower case side polymerization part due to the positioning of the reinforcement cylinder by the positioning mechanism, and the vertical orientation. Since the transmission case is reinforced by a reinforcing cylinder, the vehicle height can be increased while providing rigidity to the long vertical transmission case during work, and the vertical transmission case can be shortened during storage. The vehicle height can be lowered.

In the present invention
The positioning mechanism is provided on one of the upper case portion and the reinforcing cylinder, and when the vertical transmission case is extended, it comes into contact with the other of the upper case portion and the reinforcing cylinder to extend the vertical transmission case. Along with this, a locking portion for moving the reinforcing cylinder to the lateral transmission case side with respect to the lower case portion, and one of the lower case portion and the reinforcing cylinder are provided, and the vertical transmission case extends to a predetermined length. It is preferable that the lower case portion and the regulating portion for restricting the movement of the reinforcing cylinder to the lateral transmission case side by contacting the other of the reinforcing cylinders are provided.

According to this configuration, the structure of the positioning mechanism can be as simple as providing a locking portion and a regulating portion, and a work vehicle having a large expansion / contraction stroke of the vertical transmission case can be obtained at low cost.

It is an overall side view of a passenger management machine. It is a top view which shows the wheel support structure. It is a front view which shows the wheel support structure. It is a vertical cross-sectional view of the wheel support structure in the extended state of the vertical transmission case. It is a vertical cross-sectional view of a wheel support structure in a shortened state of a vertical transmission case. It is a vertical cross-sectional view which shows the reinforcing cylinder and the positioning mechanism in the extended state of the vertical transmission case. It is a vertical cross-sectional view which shows the reinforcing cylinder and the positioning mechanism in a shortened state of a vertical transmission case. It is a vertical cross-sectional view which shows the rotation regulation mechanism. It is a cross-sectional view which shows the rotation regulation mechanism.

Hereinafter, embodiments that are an example of the present invention will be described with reference to the drawings.
In the following description, with respect to the traveling vehicle body of the passenger management machine (an example of the "work vehicle"), the direction of the arrow F shown in FIGS. 1 and 2 is "front of the vehicle body", and the direction of the arrow B is "rear of the vehicle body". The direction of the arrow U shown in FIG. 1 is "upward of the vehicle body", the direction of the arrow D is "downward of the vehicle body", the direction of the arrow L shown in FIG. 2 is "left of the vehicle body", and the direction of the arrow R is "right of the vehicle body". ".

[Overall configuration of passenger management machine]
As shown in FIG. 1, the passenger management machine has a traveling vehicle body 3 equipped with a pair of left and right front wheels 1 as traveling wheels and a pair of left and right rear wheels 2 as traveling wheels. There is. A chemical spraying device 4 as a working device is provided at the rear of the traveling vehicle body 3. This passenger management machine can perform the work of spraying the chemicals on the crop while traveling across the crop planting line in the field where the crop has already been planted.

Both the left and right front wheels 1 and the left and right rear wheels 2 are steerably equipped. For example, a two-wheel steering state in which only two front wheels 1 are steered is displayed, or a four-wheel steering state in which the front wheels 1 and the rear wheels 2 are steered in opposite directions to travel with a small turning radius is displayed. You can do it.

The engine 5 is mounted on the front portion of the traveling vehicle body 3, and the driving unit 6 is provided on the rear portion of the traveling vehicle body 3. A transmission case 7 including a transmission (not shown) for shifting the power of the engine 5 is provided in the lower part of the traveling vehicle body 3. 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 2 in a side view. The engine 5 is supported by a front frame body 8 that covers the lower part of the engine 5. The mission case 7 and the front frame body 8 are connected to each other via the engine 5. The body frame 3F of the traveling vehicle body 3 is composed of the engine 5, the front frame body 8, and the mission case 7. The driver unit 6 is provided with a driver's seat 9 on which the driver sits, and a steering wheel 10 located in front of the driver's seat 9 to steer the front wheels 1 and the rear wheels 2. The driving unit 6 is also provided with an elevating lever 11 for elevating and lowering the chemical spraying device 4, a speed change lever 12 for changing the traveling speed of the traveling vehicle body 3, and the like.

In the traveling vehicle body 3, the power of the engine 5 is transmitted to the left and right front wheels 1 and the left and right rear wheels 2 after the power is changed by the transmission in the transmission case 7. The traveling vehicle body 3 is configured as a four-wheel drive type in which the left and right front wheels 1 and the left and right rear wheels 2 are driven.

[Support structure and drive structure of traveling wheels]
As shown in FIGS. 2, 3 and 4, a front lateral transmission case 13 extending in the vehicle body width direction is provided in the front lower portion of the traveling vehicle body 3, and from both ends of the front lateral transmission case 13 in the vehicle body width direction. The vertical transmission case 14 is extended downward. A deceleration case portion 15 is provided on each of the lower, lateral, and outer portions of the left and right vertical transmission cases 14. The left front wheel 1 as the left front traveling wheel is rotatably supported by the deceleration case portion 15 of the left vertical transmission case 14 via the axle 16. The right front wheel 1 as the right front traveling wheel is rotatably supported by the deceleration case portion 15 of the right vertical transmission case 14 via the axle 16. The front lateral transmission case 13 is supported by the front frame body 8. The left and right front wheels 1 are supported by the front portion of the traveling vehicle body 3 via the vertical transmission case 14 and the front horizontal transmission case 13. The front lateral transmission case 13 is supported by the front frame body 8 in a state where it can swing up and down with the rolling shaft core X extending in the front-rear direction of the vehicle body as a swing fulcrum. The left and right front wheels 1 are in a state where they can be rolled with respect to the traveling vehicle body 3.

As shown in FIG. 2, a front wheel differential mechanism 17 is installed in the left-right intermediate portion of the front lateral transmission case 13, and a lateral transmission shaft 18 extending left and right from the front wheel differential mechanism 17 is a front lateral transmission case 13. It is rotatably provided inside. In the left and right vertical transmission cases 14, as shown in FIG. 4, a vertical transmission shaft 19 is rotatably provided inside the vertical transmission case 14, and an upper end portion of the vertical transmission shaft 19 and a horizontal transmission shaft 18 are provided. Is interlocked and connected to the end of the gear via a gear mechanism 20. The gear 21 provided at the lower end of the vertical transmission shaft 19 and the axle drive gear 22 built in the reduction case portion 15 are engaged with each other. The power input from the transmission of the transmission case 7 to the front wheel differential mechanism 17 via the transmission shaft 23 is transmitted to the lateral transmission shaft 18, and the power of the lateral transmission shaft 18 is transmitted to the vertical transmission shaft 19 via the gear mechanism 20. The vertical transmission shaft 19 rotates, and the power of the vertical transmission shaft 19 is transmitted to the axle 16 via the gear 21 and the axle drive gear 22 to drive the front wheel 1.

As shown in FIG. 2, a lateral transmission case 24 that extends in the lateral width direction of the vehicle body is provided at the rear lower portion of the traveling vehicle body 3. The support for the lateral transmission case 24 after the rear wheel 2 is based on the same configuration as the configuration for supporting the front wheel 1 for the front lateral transmission case 13, and is used for a vertical transmission case or the like for the rear wheels. It will be described with the same reference numerals as the vertical transmission case 14 for the front wheels. As shown in FIGS. 2 and 4, the vertical transmission case 14 is extended downward from both ends of the rear horizontal transmission case 24 in the lateral width direction of the vehicle body. A deceleration case portion 15 is provided on each of the lower, lateral, and outer portions of the left and right vertical transmission cases 14. The left rear wheel 2 as the left rear traveling wheel is rotatably supported by the deceleration case portion 15 of the left vertical transmission case 14 via the axle 16. The right rear wheel 2 as the right rear traveling wheel is rotatably supported by the deceleration case portion 15 of the right vertical transmission case 14 via the axle 16. As shown in FIG. 2, the rear lateral transmission case 24 includes a mission case 7, a left transmission case portion 24a extending outward from the left lateral side of the mission case 7 to the left laterally outward of the vehicle body, and a right of the mission case 7. It has a right transmission case portion 24a extending outward from the lateral side to the right side of the vehicle body, and is supported by the rear portion of the vehicle body. The left and right rear wheels 2 are supported by the rear portion of the traveling vehicle body 3 via the vertical transmission case 14 and the rear horizontal transmission case 24.

As shown in FIG. 2, a rear wheel differential mechanism 25 is provided inside the transmission case 7. Power transmission from the rear wheel differential mechanism 25 to the rear wheels 2 is performed based on the same configuration as that for transmitting power from the front wheel differential mechanism 17 to the front wheels 1, and lateral transmission and vertical transmission for the rear wheels. The orientation transmission shaft and the like will be described with the same reference numerals as the lateral transmission shaft 18 and the vertical transmission shaft 19 for the front wheels. As shown in FIG. 2, a lateral transmission shaft 18 extending to the left and right from the rear wheel differential mechanism 25 is rotatably provided inside the rear lateral transmission case 24. In the left and right vertical transmission cases 14, as shown in FIG. 4, a vertical transmission shaft 19 is rotatably provided inside the vertical transmission case 14, and an upper end portion of the vertical transmission shaft 19 and a horizontal transmission shaft 18 are provided. Is interlocked and connected to the end of the gear via a gear mechanism 20. The gear 21 provided at the lower end of the vertical transmission shaft 19 and the axle drive gear 22 built in the reduction case portion 15 are engaged with each other. The power input from the transmission of the transmission case 7 to the rear wheel differential mechanism 25 is transmitted to the lateral transmission shaft 18, and the power of the lateral transmission shaft 18 is transmitted to the vertical transmission shaft 19 via the gear mechanism 20 in the vertical direction. The directional transmission shaft 19 rotates, and the power of the vertical transmission shaft 19 is transmitted to the axle 16 via the gear 21 and the axle drive gear 22 to drive the rear wheel 2.

[Vehicle height adjustment configuration]
In each of the left and right vertical transmission cases 14 of the front wheel 1, and in each of the left and right vertical transmission cases 14 of the rear wheel 2, as shown in FIG. 4, the vertical transmission case 14 is the horizontal transmission case 13. It is composed of an upper case portion 14A extending downward from the lateral side portion and a lower case portion 14B that is slidably fitted and connected to the upper case portion 14A and has a deceleration case portion 15 at the lower portion. There is. The vertical transmission case 14 is slidable in a direction along the axis direction of the vertical transmission shaft 19. The upper case portion 14A and the lower case portion 14B are fitted in a state where the lower case portion 14B is fitted onto the upper case portion 14A.

The vertical transmission shaft 19 is composed of an upper transmission shaft portion 19A and a lower transmission shaft portion 19B that is slidably and non-rotatably engaged with the upper transmission shaft portion 19A by spline engagement. The upper portion of the upper transmission shaft portion 19A is rotatably supported by the ends of the lateral transmission cases 13 and 24, and the lower portion of the lower transmission shaft portion 19B is rotatably supported by the lower portion of the lower case portion 14B. The vertical transmission shaft 19 can be expanded and contracted as the vertical transmission case 14 expands and contracts.

As shown in FIG. 3, the vehicle height adjusting cylinder 28 is connected to the cylinder support portion 26 provided in the upper part of the upper case portion 14A and the cylinder support portion 27 provided in the lower case portion 14B. The vehicle height adjusting cylinder 28 is composed of a hydraulic cylinder.

As shown in FIGS. 3 and 4, the vehicle height adjusting cylinder 28 is driven to the vehicle height raising side on the left front wheel side and the right front wheel side, respectively, so that the vehicle height adjusting cylinder 28 is extended. The vertical transmission case 14 and the vertical transmission shaft 19 are extended to lower the mounting height of the front wheels 1 with respect to the traveling vehicle body 3, and the vehicle height is adjusted on the left rear wheel side and the right rear wheel side, respectively. When the cylinder 28 is driven to the vehicle height raising side, the vertical transmission case 14 and the vertical transmission shaft 19 are extended by the extension operation of the vehicle height adjustment cylinder 28, and the mounting height of the rear wheels 2 with respect to the traveling vehicle body 3 Is lowered and the vehicle height is adjusted higher.

As shown in FIG. 5, the vehicle height adjusting cylinder 28 is driven to the vehicle height lowering side on each of the left front wheel side and the right front wheel side, and as shown in FIG. The orientation transmission case 14 and the vertical transmission shaft 19 are shortened to increase the mounting height of the front wheels 1 with respect to the traveling vehicle body 3, and the vehicle height adjustment cylinders 28 on the left rear wheel side and the right rear wheel side, respectively. Is driven to the vehicle height lowering side, the vertical transmission case 14 and the vertical transmission shaft 19 are shortened by the shortening operation of the vehicle height adjusting cylinder 28, and the mounting height of the rear wheels 2 on the traveling vehicle body 3 is high. The vehicle height is adjusted low.

In each of the lateral transmission case 13 for the front wheels and the lateral transmission case 24 for the rear wheels, as shown in FIG. 4, the tubular boss portion 29 extends downward from the ends of the lateral transmission cases 13 and 24. It has been skipped. The boss portion 29 is extended to be between the upper case portion 14A and the vertical transmission shaft 19, and is configured to support the upper case portion 14A from the inside. As shown in FIGS. 3 and 4, the reinforcing cylinder 30 is externally fitted to the vertical transmission case 14. The reinforcing cylinder 30 is slidably fitted in the direction along the axis of the vertical transmission shaft 19, and as shown in FIG. 6, a positioning mechanism 31 for positioning the reinforcing cylinder 30 with respect to the vertical transmission case 14 is vertically fitted. It is provided over the orientation transmission case 14 and the reinforcing cylinder 30.

Specifically, as shown in FIG. 6, the positioning mechanism 31 includes a locking portion 32 projecting from two locations in the circumferential direction of the upper case portion 14A toward the reinforcing cylinder 30, and a reinforcing cylinder 30. It has a regulating portion 33 that protrudes from four locations in the circumferential direction toward the lower case portion 14B. The regulating portion 33 is composed of a set screw screwed into the reinforcing cylinder 30 from the outer peripheral side. A first portion of the inner peripheral portion of the reinforcing cylinder 30 that allows the locking portion 32 to lift the reinforcing cylinder 30 while allowing the vertical transmission case 14 to expand and contract at two locations corresponding to the locking portions 32. An elongated hole 34 is formed, and the locking portion 32 is movably engaged with the first elongated hole 34. Of the outer peripheral portion of the lower case portion 14B, the second length that enables the regulating portion 33 to restrict the ascent of the reinforcing cylinder 30 while allowing the vertical transmission case 14 to expand and contract at four locations corresponding to the regulating portions 33. A hole 35 is formed, and the regulating portion 33 is movably engaged in the second elongated hole 35. In the present embodiment, the locking portions 32 are provided at two locations and the regulating portions 33 are provided at four locations, but the present invention is not limited to this. The locking portions 32 can be provided at one location or at three or more locations. The regulation unit 33 can be provided at three or less locations or five or more locations.

FIG. 6 shows the positional relationship between the locking portion 32 and the first slotted hole 34 in the longest state of the vertical transmission case 14, and the positional relationship between the regulating section 33 and the second slotted hole 35. ing. FIG. 7 shows the positional relationship between the locking portion 32 and the first slotted hole 34 in the shortest state of the vertical transmission case 14, and the positional relationship between the regulating section 33 and the second slotted hole 35. ing. As shown in FIGS. 6 and 7, the positioning mechanism 31 has a relative movement between the locking portion 32 by the first elongated hole 34 and the reinforcing cylinder 30, and the regulating portion 33 and the lower case portion 14B by the second elongated hole 35. By relative movement with, the vertical transmission case 14 can be expanded and contracted.

When the upper case portion 14A is raised with respect to the lower case portion 14B (when the vertical transmission case 14 is extended), the locking portion 32 is located at the upper end of the first slot 34 and the reinforcing cylinder 30 is located. The locking portion 32 moves the reinforcing cylinder 30 to the sideways transmission case side with respect to the lower case portion 14B. As shown in FIG. 6, the vertical transmission case 14 is extended, and the boss portion side polymerization portion 14X in which the boss portion 29 and the upper case portion 14A of the vertical transmission case 14 overlap, and the vertical transmission case 14 When the lower case portion side polymerization portion 14Y on which the upper case portion 14A and the lower case portion 14B overlap are located apart from each other, the locking portion 32 puts the reinforcing cylinder 30 on the boss portion side polymerization portion 14X and the lower case portion. It is located over the side polymerization site 14Y. In this way, when the vertical transmission case 14 is extended to a predetermined length (the length of the reinforcing cylinder 30 located over the boss portion side polymerization portion 14X and the lower case portion side polymerization portion 14Y), the reinforcement cylinder 30 vibrates or the like. When trying to move to the sideways transmission case side with respect to the lower case portion 14B, the regulating portion 33 is located at the upper end of the second slot 35 and comes into contact with the lower case portion 14B, and the regulating portion 33 comes into contact with the lower case portion 14B. Restrict the movement of the sideways transmission case side. That is, the positioning mechanism 31 of the reinforcing cylinder 30 so that the reinforcing cylinder 30 is positioned over the boss portion side polymerization portion 14X and the lower case portion side polymerization portion 14Y when the vertical transmission case 14 is extended to a predetermined length. Positioning is performed with respect to the vertical transmission case 14.

When each vertical transmission case 14 is extended and the vehicle height is adjusted to be high, even if the boss portion side polymerization portion 14X and the lower case portion side polymerization portion 14Y in the vertical transmission case 14 are located apart from each other. The vertical transmission case 14 is reinforced by the reinforcing cylinder 30 positioned by the positioning mechanism 31, and the elongated vertical transmission case 14 can travel in a state of having rigidity.

[Structure that enables steering operation of traveling wheels]
In the four vertical transmission cases 14, as shown in FIG. 4, a connecting portion 36 for connecting the upper case portion 14A to the end portions of the horizontal transmission cases 13 and 24 is provided on the upper portion of the upper case portion 14A, and the upper case portion 14A is provided. The case portion 14A of the lateral transmission cases 13 and 24 is rotatable with respect to the lateral transmission cases 13 and 24 with the steering axis Z substantially parallel to the extending direction of the vertical transmission case 14 as a rotation fulcrum. It is connected to the end. On each of the front wheel side and the rear wheel side, as shown in FIG. 2, a knuckle arm 37 is provided on the upper portion of the upper case portion 14A in each of the left vertical transmission case 14 and the right vertical transmission case 14. , The steering mechanism 40 is linked to the left knuckle arm 37 and the right knuckle arm 37.

As shown in FIG. 2, the steering mechanism 40 is provided with a power cylinder 41. The cylinder tube of the power cylinder 41 is supported by the lateral transmission cases 13 and 24. The left end of the cylinder rod 41a of the power cylinder 41 and the left knuckle arm 37 are interlocked and connected via the left tie rod 42, and the right end of the cylinder rod 41a and the right knuckle arm 37 connect the right tie rod 42. It is interlocked and connected via.

In the four vertical transmission cases 14, as shown in FIG. 8, a rotation regulation mechanism that regulates the relative rotation of the upper case portion 14A and the lower case portion 14B at two locations in the circumferential direction of the vertical transmission case 14. 43 is provided.

Specifically, as shown in FIGS. 8 and 9, the rotation regulating mechanism 43 includes a key 44 fixed to the outer peripheral portion of the upper case portion 14A and the inside of the lower case portion 14B in a state of being locked to the key 44. It has a key groove 45 formed on the peripheral portion. The key groove 45 is formed in a long groove extending along the extending direction of the vertical transmission case 14. When the vertical transmission case 14 expands and contracts, the key 44 moves along the extending direction of the vertical transmission case 14 in the key groove 45.

In the steering mechanism 40 for the front wheels and the steering mechanism 40 for the rear wheels, when the steering wheel 10 is rotated, the power cylinder 41 is moved to the steering wheel 10 by a linking mechanism (not shown) between the steering wheel 10 and the power cylinder 41. The cylinder rod 41a swings the left knuckle arm 37 in a direction corresponding to the operation direction of the steering wheel 10 and is operated so as to operate a stroke corresponding to the operation amount of the steering wheel 10, and the left upper case portion 14A. Is rotated by the left knuckle arm 37 with the steering axis Z as the swing fulcrum, the cylinder rod 41a swings the right knuckle arm 37, and the right upper case portion 14A is the right knuckle arm 37. The steering shaft core Z is used as a swinging fulcrum to rotate. When the left upper case portion 14A is rotated, the rotation of the left upper case portion 14A is transmitted to the left lower case portion 14B via the rotation regulation mechanism 43, and the left lower case portion 14B rotates. Then, the left front wheel 1 or the left rear wheel 2 is steered with the steering axis Z as the steering fulcrum. When the right upper case portion 14A is rotated, the rotation of the right upper case portion 14A is transmitted to the right lower case portion 14B via the rotation regulation mechanism 43, and the right lower case portion 14B rotates. Then, the right front wheel 1 or the right rear wheel 2 is steered with the steering axis Z as the steering fulcrum. Since the rotation of the upper case portion 14A is transmitted to the lower case portion 14B by the rotation regulation mechanism 43, the front wheel 1 is prevented from the twisting operation force acting on the vehicle height adjusting cylinder 28 by the rotation regulation mechanism 43. And the rear wheel 2 is steered.

[Another Embodiment]
(1) In the above embodiment, the rotation regulation mechanism 43 is provided at two locations in the circumferential direction of the vertical transmission case 14, but the present invention is not limited to this. It may be provided at one place or at three or more places.

(2) In the above embodiment, the key 44 is provided in the upper case portion 14A and the key groove 45 is formed in the lower case portion 14B. However, the key 44 is provided in the lower case portion 14B and the key is provided. The groove 45 may be formed in the upper case portion 14A.

(3) In the above-described embodiment, the example in which the reinforcing cylinder 30 is provided is shown, but the reinforcing cylinder 30 may not be provided. Further, in the case of the one provided with the reinforcing cylinder 30, the locking portion 32 of the positioning mechanism 31 is provided at two places, and the regulating portion 33 is provided at four places. It may be provided at three or more locations, and the regulation portions 33 may be provided at three or less locations or five or more locations.

(4) In the above embodiment, an example is shown in which the locking portion 32 is provided in the upper case portion 14A and the first elongated hole 34 is formed in the reinforcing cylinder 30, but the locking portion 32 is formed in the reinforcing cylinder 30. The first elongated hole 34 may be provided and formed in the upper case portion 14A.

(5) In the above embodiment, an example is shown in which the regulating portion 33 is provided in the reinforcing cylinder 30 and the second elongated hole 35 is formed in the lower case portion 14B, but the regulating portion 33 is provided in the lower case portion 14B. The second elongated hole 35 may be formed in the reinforcing cylinder 30.

(6) In the above embodiment, an example in which the steering mechanism 40 is configured as a power steering mechanism having a power cylinder 41 is shown, but the present invention is not limited to this. It may not have the power cylinder 41.

(7) In the above embodiment, only one of the front wheel 1 and the rear wheel 2 is configured to be steerable, which shows an example in which both the front wheel 1 and the rear wheel 2 are steerable. It may be.

According to the present invention, the lateral transmission case, the vertical transmission case extending downward from both ends of the lateral transmission case and supporting the traveling wheels at the lower portion, and the vertical transmission case are rotated to steer the traveling wheels. It can be applied to various work vehicles equipped with a steering mechanism.

1 Running wheel (front wheel)
2 Running wheels (rear wheels)
13 Sideways transmission case (front sideways transmission case)
14 Vertical transmission case 14A Upper case part 14B Lower case part 18 Horizontal transmission axis 19 Vertical transmission axis 24 Horizontal transmission case (rear horizontal transmission case)
28 Vehicle height adjustment cylinder 29 Boss part 30 Reinforcing cylinder 31 Positioning mechanism 32 Locking part 33 Restriction part 40 Steering mechanism 43 Rotation regulation mechanism 44 Key 45 Keyway Z Steering axis

Claims (4)

A sideways transmission case that is supported by the car body while extending in the width direction of the car body,
A vertical transmission case extending downward from both ends of the horizontal transmission case, and a vertical transmission case.
The traveling wheels supported by the lower part of the vertical transmission case and
A steering mechanism that steers the traveling wheel by rotating the vertical transmission case around a steering axis substantially parallel to the extending direction of the vertical transmission case.
A lateral transmission shaft rotatably provided inside the lateral transmission case,
A vertical transmission shaft, which is rotatably provided inside the vertical transmission case, rotates by transmitting the power of the horizontal transmission shaft, and transmits the power to the traveling wheels, is provided.
The vertical transmission case includes an upper case portion that extends downward from the end portion of the lateral transmission case in a state in which the steering mechanism is linked, and a lower case portion that is slidably fitted to the upper case portion. , And can be expanded and contracted in the direction along the extending direction of the vertical transmission case.
The vertical transmission shaft is configured to be expandable and contractible as the vertical transmission case expands and contracts.
A vehicle height adjustment cylinder that is connected to the upper case portion and the lower case portion and that expands and contracts the vertical transmission case is provided.
A rotation regulation mechanism for regulating the relative rotation between the upper case portion and the lower case portion with the steering shaft core as the rotation center is provided.
The rotation regulating mechanism is formed in one of the upper case portion and the lower case portion and extends along the extending direction of the vertical transmission case, and the other of the upper case portion and the lower case portion. A work vehicle provided with a key that is movably inserted into the key groove along the extending direction of the vertical transmission case. The work vehicle according to claim 1, wherein the rotation regulation mechanism is provided at a plurality of locations in the circumferential direction of the vertical transmission case. The lateral transmission case is provided with a boss portion that extends downward from the end portion of the lateral transmission case between the upper case portion and the vertical transmission shaft and supports the upper case portion from the inside.
The vertical transmission case is provided with a reinforcing cylinder that is slidably fitted in the direction along the axis of the vertical transmission shaft.
When the vertical transmission case is extended, the boss portion side polymerization portion where the upper case portion and the boss portion of the vertical transmission case overlap, and the upper case portion of the vertical transmission case. The work vehicle according to claim 1 or 2, further comprising a lower case portion side polymerization portion on which the lower case portion overlaps, and a positioning mechanism for positioning the reinforcing cylinder in a state where the reinforcing cylinder is located over the lower case portion. To the positioning mechanism
It is provided on one of the upper case portion and the reinforcing cylinder, and when the vertical transmission case is extended, it comes into contact with the other of the upper case portion and the reinforcing cylinder, so that the reinforcing cylinder accompanies the extension of the vertical transmission case. With respect to the lower case portion, and a locking portion that moves the sideways transmission case side.
It is provided on one of the lower case portion and the reinforcing cylinder, and when the vertical transmission case extends to a predetermined length, it comes into contact with the other of the lower case portion and the reinforcing cylinder, so that the lateral transmission case side of the reinforcing cylinder is provided. The work vehicle according to claim 3, which is provided with a regulatory unit that regulates movement to.

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