JP2006248266A - Mowing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mowing machine capable of turning and traveling with a small turn and a strong travel. <P>SOLUTION: The mowing machine is equipped with a pair of front wheel clutches 54 separately switching the power transmission relative to the right and left front wheels, and a pair of rear wheel clutch 35 separately switching the power transmission relative to the right and left rear wheels 2. Operation parts 54a, 35a of each front wheel clutch 54 and each rear wheel clutch 35, and a steering sensor 41 are interlocked with a steering means 40. When the front wheel 1 is in a steering state at the straight forward travel side, the steering means 40 operates each front wheel clutch 54 and each rear wheel 35 into an ON state. When the front wheel 1 is in a steering state on the horizontally directed side, the steering means 40 operates the front wheel clutch 54, the rear wheel clutch 35 corresponding to the front wheel 1, and the rear wheel 2 on the inside of the turn to an OFF state, and operates the front wheel clutch 54, an the rear wheel clutch 35 corresponding to the front wheel 1, and the rear wheel 2 on the outside of the turn to the ON state. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a mowing machine that includes a pair of left and right front wheels that can be steered and a pair of left and right non-steering rear wheels that can be driven.

Conventionally, the mower has a steering clutch 27 for intermittently transmitting and receiving power to the front wheel differential 19 and the left and right rear wheels 2 as shown in Patent Document 1, for example, and a set angle from the straight traveling posture of the front wheel 1 In conjunction with the above steering operation, a device having an interlocking means for reversibly disconnecting the steering clutch 27 for the rear wheel 2 inside the turn has been developed.
That is, when driving straight, the vehicle runs with the driving force of the left and right front wheels and left and right rear wheels. Developed one that turns with power.

Conventionally, as shown in Patent Document 2, for example, a pair of left and right front wheels 1 are provided so as to be freely rotatable, a rear wheel differential 11 having a differential lock function, and a transmission system from the rear wheel differential 11 to the left and right rear wheels 2. The side clutch 12 interposed in each of the parts, that the front wheel 1 steered more than the set angle from the straight running posture, and the steering sensor 10 that detects the steering direction, when the straight traveling is detected by the steering sensor 10, The differential wheel 11 is differentiated and both side clutches 12 are engaged and held in an operating state. When the steering sensor 10 detects a steering operation of a set angle or more, the rear wheel differential 11 is differentially locked and the rear side of the turn is turned. A device equipped with a control device 13 for turning off the side clutch 12 for the wheel 2 has been developed.
In other words, when driving straight, the vehicle is driven by the driving forces of the left and right rear wheels. did.

JP 2003-170859 A (paragraphs [0018], [0022], [0023], FIGS. 2 and 3)

JP 2004-113132 A (paragraphs [0019]-[0022], FIG. 3)

  When the conventional technique shown in Patent Document 1 is adopted, a small turn is not likely to appear sufficiently to drive the left and right front wheels while the rear wheels inside the turn follow and turn during turning. There was a thing. In particular, when the turf is wet, the front wheels sometimes slip and rotate due to the interlocking of the front wheel differentials of the left and right front wheels.

  When the conventional technique shown in Patent Document 2 is adopted, there is a case where the propulsive force is insufficient when turning, particularly on an inclined ground.

  An object of the present invention is to provide a mower capable of powerfully traveling with a small turning radius during turning while being able to travel powerfully by the driving force of the left and right front wheels and left and right rear wheels during straight traveling. There is to do.

In the mower according to the first aspect of the present invention, the pair of front wheel clutches that separate the transmission to the pair of left and right steering front wheels and the transmission to the pair of left and right non-steering rear wheels are separated from each other. A pair of rear wheel clutches,
When the pair of left and right front wheels are in a lateral steering state in which the pair of left and right front wheels is laterally set to a set angle or more from a straight forward direction, the rear wheel clutch corresponding to the front wheel outside the turn and the rear wheel corresponding to the rear wheel outside the turn When the wheel clutch is engaged, the front wheel clutch corresponding to the front wheel inside the turn and the rear wheel clutch corresponding to the rear wheel inside the turn are disengaged, and the pair of left and right front wheels are steered straight. Steering means for operating the front wheel clutches and the rear wheel clutches in linkage with the steering operation of the front wheels so that the front wheel clutches and the rear wheel clutches are engaged when in the state. Is provided.

  That is, when the front wheel is steered, the steering means is linked to the steering operation of the front wheel to operate each front wheel clutch and each rear wheel clutch, and the front wheel is in a straight-ahead steering state. The front wheel clutch and the rear wheel clutch are engaged, and the left and right front wheels and the left and right rear wheels are driven. When the front wheels are steered sideways, the front wheel clutches and rear wheel clutches corresponding to the front wheels and rear wheels inside the turn are turned off, and the front wheels and rear wheels inside the turns are idle. Thus, the front wheel clutch and the rear wheel clutch corresponding to the front wheel and the rear wheel outside the turn are engaged, and the front wheel and the rear wheel outside the turn are driven.

  Thus, when the front wheel is steered to the straight-ahead steering state, the vehicle body travels in the direction of the front wheel by driving the left and right front wheels and the left and right rear wheels. When the front wheel is steered to the sideward steering state, the vehicle body turns by the direction of the front wheel and the driving of the front wheel and the rear wheel outside the turn. At this time, the front wheel and the rear wheel inside the turn enter an idle state and follow and rotate, and the front wheel and the rear wheel outside the turn are driven to exert a propulsive force.

  Therefore, according to the first aspect of the present invention, when traveling straight ahead, both the left and right front wheels and the left and right rear wheels exhibit propulsive power, and work advantageously such that the vehicle can run efficiently even on sloping ground. Even when turning, the front and rear wheels on the inside of the turn follow and rotate, and the front and rear wheels on the outside of the turn also exert a driving force. Thus, it is possible to perform an advantageous operation such as efficiently turning a small turn, turning with a powerful run, and generating work leakage as much as possible.

In the second invention, in the configuration of the first invention, a front wheel differential mechanism that transmits power to the pair of left and right front wheels, and a rear wheel differential mechanism that transmits power to the pair of left and right rear wheels. Prepared,
When the pair of left and right front wheels are in the sideways steering state, the steering means switches the front wheel differential mechanism and the rear wheel differential mechanism to the differential operation disabled state, and the pair of left and right front wheels When the wheel is in the straight traveling side steering state, the steering means is configured to switch the front wheel differential mechanism and the rear wheel differential mechanism to a differential operable state.

  That is, when the front wheel is steered, the steering means is linked to the steering operation of the front wheel to operate the front wheel differential mechanism and the rear wheel differential mechanism, and the front wheel is in a straight-ahead steering state. In such a case, the front wheel differential mechanism and the rear wheel differential mechanism are switched to a differentially operable state. When the front wheels are turned sideways, the front wheel differential mechanism and the rear wheel differential mechanism are switched to the differential operation disabled state so that the front wheels and the rear wheels outside the turn are driven. . As a result, when the front wheel is steered to the straight side, the left and right front wheels are driven with the front wheel differential mechanism causing a difference in rotational speed between the left and right front wheels depending on the conditions of the traveling ground. The rear wheels are driven in a state where a difference in rotational speed between the left and right rear wheels is generated by the rear wheel differential mechanism.

  Therefore, according to the second aspect of the present invention, the front and rear wheels on the inside of the turn follow and turn during turning, but the left and right front wheels depend on the situation of the traveling ground when traveling straight ahead. And the left and right rear wheels can differentially run and work stably, and the turf can be kept intact.

Embodiments of the present invention will be described below with reference to the drawings.
[First embodiment]
As shown in FIG. 1, a pair of left and right steering operations and driveable front wheels 1 and a pair of left and right non-steering driveable rear wheels 2 are provided, and an engine 3 located at the front of the vehicle body is provided. A mowing device 10 is connected via a link mechanism 6 between the front and rear wheels of a vehicle body frame 5 of a self-propelled vehicle body provided with a driving unit equipped with a driving unit equipped with a driving seat 4 located at the rear of the vehicle body, A transmission type mower is configured to transmit the driving force of the engine 3 to the mowing device 10 from the mission case 7 located in the position.

  This mowing machine performs mowing and lawn mowing work. When an elevating cylinder (not shown) linked to the link mechanism 6 is telescopically operated, the elevating cylinder moves the link mechanism 6 up and down with respect to the vehicle body frame 5. The mowing device 10 is moved up and down into a lowering work state in which the grounding gauge ring 11 is grounded on the ground and a non-working state in which the grounding gauge ring 11 is lifted from the ground. When the mowing apparatus 10 is moved down and the self-propelled vehicle body is driven, the mowing apparatus 10 is rotationally driven around the axis of the vehicle body vertically at a plurality of locations in the lateral direction of the vehicle body inside the cutting blade housing 12. Grass and turf are trimmed by the blade-shaped rotary mowing blade 13.

  As shown in FIG. 2, each front wheel 1 is supported by a front wheel support case 20 so as to be rotatable around the front axle. A front wheel support case 20 for each of the left and right front wheels 1 and 1 is steered in the vertical direction of the vehicle body at the end of a front wheel drive case 21 that is connected to the vehicle body frame 5 in a rolling manner around a rolling shaft core 21a facing the vehicle body. The shaft P is supported so as to be swingable in the longitudinal direction of the vehicle body.

  A swing arm 22 provided in each front wheel support case 20 so as to be swingable integrally around the steering axis P is interlocked by a tie rod 23. A knuckle arm 24 provided on one front wheel support case 20 so as to be swingable integrally around the steering axis P is linked to a pitman arm 26 via a linkage rod 25. The pitman arm 26 includes a sector gear 27 that is provided so as to rotate integrally with the pitman arm 26, a pinion gear 28 that meshes with the sector gear 27, and a rotatable handle that is connected to the pinion gear 28 so as to be rotatable together. It is linked to the steering wheel 29 via a shaft.

  As shown in FIG. 3, the driving force of the engine 3 is transmitted from the input shaft 7a of the mission case 7 to a transmission transmission (not shown) in the transmission case 7 in the transmission case 7, and this transmission allows the forward side and The driving force switched to the reverse side and shifted to a predetermined rotational speed is transmitted to the input shaft 51 of the front wheel drive case 21 via the rotating shaft 50, and the driving force of the input shaft 51 is connected to the bevel gear mechanism 52. The front wheel drive case 21 is decelerated by the single rotation transmission shaft 53 and branched to the left front wheel side and the right front wheel side, and branched to the left front wheel side from the one end side of the rotation transmission shaft 53. The driving force transmitted to the left front wheel 1 via the front wheel clutch 54 located inside and branched to the right front wheel side is applied to the inside of the front wheel drive case 21 from the other end side of the rotation transmission shaft 52. Through the front wheel clutch 54 which are configured to be transmitted to the right front wheel 1.

  As shown in FIG. 3, each of the rear wheels 2 is rotatably supported on a lateral side portion of the mission case 7. The driving force of the rear wheel output shaft 30 of the transmission unit in the transmission case 7 is decelerated by the bevel gear mechanism 31 and the single rotation transmission shaft 32 and branched to the left rear wheel side and the right rear wheel side, The driving force branched to the left rear wheel side is transmitted from one end of the rotation transmission shaft 32 to the left rear wheel 2 via the rear wheel clutch 35 located in the transmission case 7 and branched to the right rear wheel side. The generated driving force is transmitted from the other end of the rotary transmission shaft 32 to the right rear wheel 2 via a rear wheel clutch 35 located in the transmission case 7.

  As shown in FIG. 3, each front wheel clutch 54 is configured to be switched between an on state and a disconnected state by operating an operation portion 54 a that is an electric actuator provided outside the front wheel drive case 21. is there. Each of the rear wheel clutches 35 is configured to be switched between an on state and a disengaged state by operating an operation portion 35a that is an electric actuator provided outside the transmission case 7. The operation portions 54a of both front wheel clutches 54 and the operation portions 35a of both rear wheel clutches 35 are linked to the steering means 40, and the steering sensor 41 is also linked to the steering means 40.

  The steering sensor 41 is composed of a rotary potentiometer linked to the pitman arm 26, and the steering swing angle of the pair of left and right front wheels 1, 1 based on the detection result of the swing position and swing direction of the pitman arm 26. The steering swing direction is detected, and the detection result is output to the steering means 40 as an electrical signal.

  The steering means 40 is configured using a microcomputer, and is configured to switch between the front wheel clutches 54 and the rear wheel clutches 35 based on the detection result from the steering sensor 41.

That is, the steering means 40 inputs the detection result of the steering sensor 41, and based on this detection result, the pair of left and right front wheels 1, 1 are in the straight-ahead steering state and the pair of left and right front wheels 1, 1. Is a left-hand side steering state that has swung sideways from the straight direction to the left side by a set angle (10 to 15 degrees), and a pair of left and right front wheels 1 and 1 are set from the straight side to the right side. 10 to 15 degrees), it is determined whether the vehicle is in the right-hand side side steering state that has been swung sideways.
The straight-ahead side steering state of the pair of left and right front wheels 1 is a steering state in which the front wheel 1 is in a straight steering direction, and a posture in which the front wheel 1 is swung from a straight direction to a left lateral direction. However, even if the front wheel 1 is in a posture in which the front wheel 1 is swung from a straight direction to a right side, the steering state in which the horizontal swing angle is less than a set angle (10 to 15 degrees). The steering state in which the lateral swing angle is in the right lateral posture with the angle less than the set angle (10 to 15 degrees) is set.

  When the steering means 40 determines that the pair of left and right front wheels 1 and 1 are in the straight-ahead side steering state, the steering unit 40a operates the operating unit 54a of both front wheel clutches 54 and the operating unit 35a of both rear wheel clutches 35 and 35. By switching to the clutch engagement side, both front wheel clutches 54 and both rear wheel clutches 35 are operated to the engagement state.

  When the steering means 40 determines that the pair of left and right front wheels 1 and 1 are in the left side steering state, the steering means 40 applies the operation portion 54 a of the front wheel clutch 54 corresponding to the left front wheel 1 and the left rear wheel 2. By switching the operation portion 35a of the corresponding rear wheel clutch 35 to the clutch disengagement side, the front wheel clutch 54 of the left front wheel 1 and the rear wheel clutch 35 of the left rear wheel 2 are operated to the disengaged state. At the same time, the front wheel clutch 54 of the right front wheel 1 is operated by switching the operation portion 54a of the front wheel clutch 54 corresponding to the right front wheel 1 and the operation portion 35a of the rear wheel clutch 35 corresponding to the right rear wheel 2 to the clutch engagement side. And, the rear wheel clutch 35 of the right rear wheel 2 is operated to be in the engaged state.

  When the steering means 40 determines that the pair of left and right front wheels 1 and 1 are in the rightward side steering state, the steering means 40 applies the operation portion 54a of the front wheel clutch 54 corresponding to the right front wheel 1 and the right rear wheel 2 to the right front wheel 1. By switching the operation portion 35a of the corresponding rear wheel clutch 35 to the clutch disengagement side, the front wheel clutch 54 of the right front wheel 1 and the rear wheel clutch 35 of the right rear wheel 2 are operated to the disengaged state. At the same time, the front wheel clutch of the left front wheel 1 is operated by switching the operation portion 54a of the front wheel clutch 54 corresponding to the left front wheel 1 and the operation portion 35a of the rear wheel clutch 35 corresponding to the left rear wheel 2 to the clutch engagement side. 54 and the rear wheel clutch 35 of the left rear wheel 2 are operated.

  That is, by rotating the steering wheel 29, the pitman arm 26 is swung, the knuckle arm 24 is swung through the interlocking rod 25, and one front wheel support case 20 is swung. The support case 20 swings the other front wheel support case 20 via the tie rod 23, and the left and right front wheels 1 swing around the steering axis P corresponding to the rotational direction of the steering wheel 29 with respect to the vehicle body frame 5. A swing angle corresponding to the operation angle of the steering wheel 29 is swung in the moving direction. That is, the left and right front wheels 1 can be steered in a straight steering direction or in a lateral steering state that swings from the straight driving direction to the left or side.

  Then, when the left and right front wheels 1 are steered to a straight-ahead side steered state, that is, a straight steering direction or a swing angle less than a set angle (10 to 15 degrees) from the straight direction to the left side direction. If the steering operation is performed in a state in which the steering posture is a swinging posture in which the swinging angle is less than a set angle (10 to 15 degrees) from the straight traveling direction to the right lateral direction, the steering means 40 is swung. Based on the detection result of the steering sensor 41, the front wheel clutch 54 and the rear wheel clutch 35 are operated in the engaged state in conjunction with the steering operation of the front wheel 1. As a result, the left and right front wheels 1 and the left and right rear wheels 2 are driven by the driving force from the engine 3, and the self-propelled vehicle travels straight or substantially straight by the driving forces of the left and right front wheels 1 and the left and right rear wheels 2. .

  When the left and right front wheels 1 are steered to a left lateral side steered state that is laterally greater than a set angle (10 to 15 degrees) from a straight forward direction to a left lateral direction, the steering means 40 is operated by the steering sensor 41. Based on the detection result, the front wheel clutch 54 corresponding to the left front wheel 1 located inside the turning of the left and right front wheels 1, 1 and the left and right rear wheels 2, 2 are linked to the steering operation of the front wheel 1. The rear wheel clutch 35 corresponding to the left rear wheel 2 located inside the turn is operated in the disengaged state, and the right front wheel 1 located outside the turn of the left and right front wheels 1 and 1 is handled. The front wheel clutch 54 and the rear wheel clutch 35 corresponding to the right rear wheel 2 located on the outer turning side of the left and right rear wheels 2 and 2 are operated to enter the engaged state. As a result, the left front wheel 1 and the rear wheel 2 located on the inner side of the turn are in an idle state, and the right front wheel 1 and the rear wheel 2 located on the outer side of the turn are driven by the driving force from the engine 3. The self-propelled vehicle turns to the left while the left front wheel 1 and the rear wheel 2 positioned on the inner side of the turning are driven and rotated by the driving force of the right front wheel 1 and the rear wheel 2 positioned on the outer side of the turning.

  When the left and right front wheels 1 are steered from a straight travel direction to a right lateral direction to a right lateral side lateral steering state that is laterally greater than a set angle (10 to 15 degrees), the steering means 40 is operated by the steering sensor 41. Based on the detection result, the front wheel clutch 54 corresponding to the right front wheel 1 located inside the turning of the left and right front wheels 1, 1 and the left and right rear wheels 2, 2 are linked to the steering operation of the front wheel 1. The rear wheel clutch 35 corresponding to the right rear wheel 2 located on the inner side of the vehicle is operated in a disengaged state, and the left front wheel 1 located on the outer side of the left and right front wheels 1 and 1 is operated. The front wheel clutch 54 and the rear wheel clutch 35 corresponding to the left rear wheel 2 located outside the turning of the left and right rear wheels 2 and 2 are operated to be in the engaged state. As a result, the right front wheel 1 and the rear wheel 2 located on the inner side of the turn are in an idle state, and the left front wheel 1 and the rear wheel 2 located on the outer side of the turn are driven by the driving force from the engine 3. The self-running vehicle body turns in the right direction while the right front wheel 1 and the rear wheel 2 positioned on the inside of the turn are rotated by the driving force of the left front wheel 1 and the rear wheel 2 located on the outside of the turn.

[Second Embodiment]
FIG. 4 shows a traveling drive structure of a riding mower with another embodiment. In this traveling drive structure, the driving force of the engine 3 is transmitted from the input shaft 7a of the transmission case 7 to the transmission case 7. The driving force transmitted to the transmission unit (not shown) of the traveling mission, switched to the forward side or the reverse side by the transmission unit, and shifted to a predetermined rotational speed is transmitted via the rear wheel output shaft 30. The rear wheel clutch 35 is transmitted to the input portion of the rear wheel differential mechanism 60 located inside the mission case 7, and the driving force of the left wheel output shaft 60 a in the rear wheel differential mechanism 60 is located inside the mission case 7. The right rear wheel is transmitted to the left rear wheel 2 via the rear wheel clutch 35 and the driving force of the right wheel output shaft 60 b in the rear wheel differential mechanism 60 is located inside the transmission case 7. It is configured to be transmitted to. In addition, the front wheel output of the transmission unit of the traveling mission is transmitted to the input part of the front wheel differential mechanism 61 located inside the front wheel drive case 21 via the rotary shaft 50, The driving force of the wheel output shaft 61a is transmitted to the left front wheel 1 via the front wheel clutch 54 located inside the front wheel driving case 21, and the driving force of the right wheel output shaft 61b in the front wheel differential mechanism 61 is front wheel driven. It is configured to be transmitted to the right front wheel 1 via a front wheel clutch 54 located inside the case 21.

  This mower is further configured as follows.

  Each of the front wheel clutches 54 is configured to be switched between an on state and a disengaged state by operating an operation portion 54a formed of an electric actuator provided outside the front wheel drive case 21. Each of the rear wheel clutches 35 is configured to be switched between an on state and a disengaged state by operating an operation portion 35a formed of an electric actuator provided outside the mission case 7.

  Both the front wheel differential mechanism 61 and the rear wheel differential mechanism 60 have a differential lock function. In the front wheel differential mechanism 61, the differential lock function is turned off so that the differential of the left and right front wheels 1 can be revealed by operating the electric differential lock operation portion 61c provided outside the front wheel drive case 21. The differential lock function is turned on so that the front wheel 1 corresponding to the other front wheel clutch 54 in the engaged state can be driven even when one front wheel clutch 54 is in the disengaged state. The differential operation disabled state is switched to. In the rear wheel differential mechanism 60, the differential lock function is turned off so that the differential of the left and right rear wheels 2 can be displayed by operating the electric differential lock operation portion 60c provided outside the transmission case 7. The differential lock function so that the rear wheel 2 corresponding to the other rear wheel clutch 35 in the engaged state can be driven even when the one rear wheel clutch 35 is in the disengaged state. It is switched to the differential operation disabled state in which is turned on.

  Steering means 40 includes the operation portion 54a of the front wheel clutch 54, the differential lock operation portion 61c of the front wheel differential mechanism 61, the operation portion 35a of the rear wheel clutch 35, and the differential lock operation portion 60c of the rear wheel differential mechanism 60. The steering means 41 is also linked to the steering sensor 41 configured in the same manner as the steering sensor 41 of the first embodiment.

  The steering means 40 is configured by using a microcomputer, and based on the detection result from the steering sensor 41, the front wheel clutches 54, the rear wheel clutches 35, the front wheel differential mechanism 61, and the rear wheel differential mechanism 60. Are configured to be switched.

That is, the steering means 40, like the steering means 40 of the first embodiment, is based on the detection result of the steering sensor 41, and the pair of left and right front wheels 1, 1 are in the straight-ahead side steering state and leftward. It is determined whether the vehicle is in the sideways steering state or the rightward side steering state.
As the straight-ahead side steering state, the left-side side-side steering state, and the right-side side-side steering state of the pair of left and right front wheels 1, the straight-ahead side steering state, the left-side side-side steering state of the first embodiment, The same thing as the right side steering state is set.

  When the steering means 40 determines that the pair of left and right front wheels 1 and 1 are in a straight-ahead steering state, the operating portions 54a and 35a of both front wheel clutches 54 and both rear wheel clutches 35 and 35 are moved to the clutch engagement side. By performing the switching operation, both the front wheel clutches 54 and both the rear wheel clutches 35, 35 are operated to enter the engaged state. At the same time, the front wheel differential mechanism 61 and the rear wheel differential mechanism 60 are switched to the differentially operable state by operating the differential lock operation portions 61c, 60c of the front wheel differential mechanism 61 and the rear wheel differential mechanism 60 to the release side. Manipulate.

  When the steering means 40 determines that the pair of left and right front wheels 1 and 1 are in the left side steering state, the steering means 40 applies the operation portion 54 a of the front wheel clutch 54 corresponding to the left front wheel 1 and the left rear wheel 2. By switching the operation portion 35a of the corresponding rear wheel clutch 35 to the clutch disengagement side, the front wheel clutch 54 of the left front wheel 1 and the rear wheel clutch 35 of the left rear wheel 2 are operated to the disengaged state. At the same time, the front wheel clutch 54 of the right front wheel 1 is operated by switching the operation portion 54a of the front wheel clutch 54 corresponding to the right front wheel 1 and the operation portion 35a of the rear wheel clutch 35 corresponding to the right rear wheel 2 to the clutch engagement side. And, the rear wheel clutch 35 of the right rear wheel 2 is operated to be in the engaged state. Further, the front wheel differential mechanism 61 and the rear wheel differential mechanism 60 are switched to a state incapable of differential operation by switching the differential lock operation portions 61c and 60c of the front wheel differential mechanism 61 and the rear wheel differential mechanism 60 to the differential lock side. Manipulate.

  When the steering means 40 determines that the pair of left and right front wheels 1 and 1 are in the rightward side steering state, the steering means 40 applies the operation portion 54a of the front wheel clutch 54 corresponding to the right front wheel 1 and the right rear wheel 2 to the right front wheel 1. By switching the operation portion 35a of the corresponding rear wheel clutch 35 to the clutch disengagement side, the front wheel clutch 54 of the right front wheel 1 and the rear wheel clutch 35 of the right rear wheel 2 are operated to the disengaged state. At the same time, the front wheel clutch of the left front wheel 1 is operated by switching the operation portion 54a of the front wheel clutch 54 corresponding to the left front wheel 1 and the operation portion 35a of the rear wheel clutch 35 corresponding to the left rear wheel 2 to the clutch engagement side. 54 and the rear wheel clutch 35 of the left rear wheel 2 are operated. Further, the front wheel differential mechanism 61 and the rear wheel differential mechanism 60 are switched to a state incapable of differential operation by switching the differential lock operation portions 61c and 60c of the front wheel differential mechanism 61 and the rear wheel differential mechanism 60 to the differential lock side. Manipulate.

  That is, when the left and right front wheels 1 are steered to a straight-ahead side steering state, that is, a straight steering direction or a swing angle less than a set angle (10 to 15 degrees) from the straight direction to the left lateral direction. If the steering operation is performed in a state in which the steering posture is a swinging posture in which the swinging angle is less than a set angle (10 to 15 degrees) from the straight traveling direction to the right lateral direction, the steering means 40 is swung. Based on the detection result of the steering sensor 41, the front wheel clutch 54 and the rear wheel clutch 35 are operated in the engaged state in conjunction with the steering operation of the front wheel 1. As a result, the left and right front wheels 1 and the left and right rear wheels 2 are driven by the driving force from the engine 3, and the self-propelled vehicle travels straight or substantially straight by the driving forces of the left and right front wheels 1 and the left and right rear wheels 2. . At this time, the steering means 40 switches the front wheel differential mechanism 61 and the rear wheel differential mechanism 60 to the differential operation enabled state (diff lock release state). Depending on the conditions of the traveling ground, the left and right front wheels 1 and left and right rear wheels 2 are differentially generated.

  When the left and right front wheels 1 are steered to a left lateral side steered state that is laterally greater than a set angle (10 to 15 degrees) from a straight forward direction to a left lateral direction, the steering means 40 is operated by the steering sensor 41. Based on the detection result, the front wheel clutch 54 corresponding to the left front wheel 1 located inside the turning of the left and right front wheels 1, 1 and the left and right rear wheels 2, 2 are linked to the steering operation of the front wheel 1. The rear wheel clutch 35 corresponding to the left rear wheel 2 located inside the turn is operated in the disengaged state, and the right front wheel 1 located outside the turn of the left and right front wheels 1 and 1 is handled. The front wheel clutch 54 and the rear wheel clutch 35 corresponding to the right rear wheel 2 located on the outer turning side of the left and right rear wheels 2 and 2 are operated to be engaged, and further, the front wheel differential mechanism 61 and the rear wheel difference are operated. The movement mechanism 60 is in a differential operation disabled state (diff lock state). The switching operation. As a result, the left front wheel 1 and the rear wheel 2 located on the inner side of the turn are in an idle state, and the right front wheel 1 and the rear wheel 2 located on the outer side of the turn are driven by the driving force from the engine 3. The self-running vehicle body turns leftward while the left front wheel 1 and the rear wheel 2 positioned on the inside of the turn follow and rotate by the driving force of the right front wheel 1 and the rear wheel 2 located on the outside of the turn.

  When the left and right front wheels 1 are steered from a straight travel direction to a right lateral direction to a right lateral side lateral steering state that is laterally greater than a set angle (10 to 15 degrees), the steering means 40 is operated by the steering sensor 41. Based on the detection result, the front wheel clutch 54 corresponding to the right front wheel 1 located inside the turning of the left and right front wheels 1, 1 and the left and right rear wheels 2, 2 are linked to the steering operation of the front wheel 1. The rear wheel clutch 35 corresponding to the right rear wheel 2 located on the inner side of the vehicle is operated in a disengaged state, and the left front wheel 1 located on the outer side of the left and right front wheels 1 and 1 is operated. The front wheel clutch 54 and the rear wheel clutch 35 corresponding to the left rear wheel 2 located on the outer turning side of the left and right rear wheels 2 and 2 are operated to be engaged, and further, the front wheel differential mechanism 61 and the rear wheel difference are operated. The movement mechanism 60 is in a differential operation disabled state (diff lock state). The switching operation. As a result, the right front wheel 1 and the rear wheel 2 located on the inner side of the turn are in an idle state, and the left front wheel 1 and the rear wheel 2 located on the outer side of the turn are driven by the driving force from the engine 3. The self-running vehicle body turns in the right direction while the right front wheel 1 and the rear wheel 2 positioned on the inside of the turn are rotated by the driving force of the left front wheel 1 and the rear wheel 2 located on the outside of the turn.

[Another Example]
Instead of the electrically operated front wheel clutch 54 and the rear wheel clutch 35 configured to be switched by an electric actuator located outside the front wheel drive case 21 and the transmission case 7 as in the above embodiments, an electromagnetic clutch or a hydraulic clutch is used. A front wheel clutch or a rear wheel clutch may be adopted.
Further, instead of the steering means 40 using the microcomputer as in the above embodiment, the pitman arm 26, the knuckle arm 24 and the swing arm 22 of the front wheel 1, the front wheel clutch 54, the rear wheel clutch 35, and the front wheel differential. The front wheel clutch 54, the rear wheel clutch 35, and the front wheel differential mechanism 61 are operated by interlocking the operating unit of the mechanism 61 and the rear wheel differential mechanism 60 using a swing link or a rod, and the steering operation force of the front wheel 1. Alternatively, a mechanical interlocking means for switching the rear wheel differential mechanism 60 may be employed.
Accordingly, the electrically operated front wheel clutch 54, the rear wheel clutch 35, the electromagnetic clutch, the hydraulic clutch, the machine operated front wheel clutch, the rear wheel clutch, and the like are collectively referred to simply as the front wheel clutch 54 and the rear wheel clutch 35. Further, the steering means 40 using the microcomputer, the mechanical interlocking means, and the like are collectively referred to as the steering means 40.

Side view of the entire riding mower Top view of the front wheel steering operation device Schematic showing front and rear wheel drive structure and front and rear wheel clutch operation structure Schematic showing the front and rear wheel drive structure with another embodiment and the operation structure of the front and rear wheel clutch

Explanation of symbols

1 front wheel 2 rear wheel 35 rear wheel clutch 54 front wheel clutch 60 rear wheel differential mechanism 61 front wheel differential mechanism

Claims (2)

A pair of front wheel clutches that separates and transmits power to the pair of left and right steerable front wheels, and a pair of rear wheel clutches that separate and transmit power to the pair of left and right non-steered rear wheels,
When the pair of left and right front wheels are in a lateral steering state in which the pair of left and right front wheels is laterally set to a set angle or more from a straight forward direction, the rear wheel clutch corresponding to the front wheel outside the turn and the rear wheel corresponding to the rear wheel outside the turn When the wheel clutch is engaged, the front wheel clutch corresponding to the front wheel inside the turn and the rear wheel clutch corresponding to the rear wheel inside the turn are disengaged, and the pair of left and right front wheels are steered straight. Steering means for operating the front wheel clutches and the rear wheel clutches in linkage with the steering operation of the front wheels so that the front wheel clutches and the rear wheel clutches are engaged when in the state. Mower that is equipped with. A front wheel differential mechanism that transmits power to the pair of left and right front wheels, and a rear wheel differential mechanism that transmits power to the pair of left and right rear wheels,
When the pair of left and right front wheels are in the sideways steering state, the steering means switches the front wheel differential mechanism and the rear wheel differential mechanism to the differential operation disabled state, and the pair of left and right front wheels 2. The structure according to claim 1, wherein the steering means is configured to switch the front wheel differential mechanism and the rear wheel differential mechanism to a differentially operable state when a wheel is in the straight traveling side steering state. Mowing machine.

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