JP2001122148A - Tending work vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tending work vehicle where a side clutch for both rear wheels is disengaged and only a front wheel of one is driven during turning. SOLUTION: In this tending work vehicle, a working machine is mounted to a vehicular front part via a linkage and an elevating cylinder, and a driver's seat, a steering handle, and an engine transmission case are attached to a vehicular rear part. It is constituted so that a direction change operation of the front wheel operated by the steering handle is detected for disengaging the side clutch for both rear wheels and driving only the one front wheel during turning.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a maintenance work vehicle for performing operations such as ground work such as tilling and medium tillage, or ridges and mulching, and transplanting or harvesting of vegetable seedlings.

[0002]

2. Description of the Related Art In the prior art, a three-wheel drive type is provided in which a body frame is arranged in the front-rear direction, one front wheel is arranged as a steering wheel at a front part of the body, and two rear wheels are arranged at a rear part. 2. Description of the Related Art A riding type management work vehicle is known in which a power unit is disposed at a rear part of the vehicle, a driving unit is disposed in front of the power unit, and a working machine is disposed at an abdomen between a front wheel and a rear wheel so as to be able to move up and down. In such a conventional management work vehicle, the turning operation of the front wheel operated by the steering wheel is detected, and only the driving of the rear wheel inside the turning is stopped at the time of turning.

[0003]

However, stopping only the driving of the rear wheel on the inside of the turn at the time of turning has caused inconveniences such as pushing the earth by the front wheels and increasing the turning radius.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned disadvantages, and provides the following management work vehicle. That is, in a maintenance work vehicle in which a work machine is mounted on a front portion of a vehicle body via a link mechanism and a lifting cylinder and a driver's seat, a steering wheel, an engine, and a transmission case are mounted on a rear portion of the vehicle body, a side clutch of both rear wheels during turning is provided. , And only one front wheel is driven. The side clutch of both rear wheels is a management work vehicle characterized in that when the steering angle of the steering wheel becomes larger than a predetermined value, the side clutch is disengaged by the operation of a weight-type cam provided in the steering operation transmission unit. In addition, the side clutch for both rear wheels is a management work vehicle that is disengaged by operating both side clutch pedals.

[0005]

Embodiments of the present invention will be described below with reference to the drawings. 1 is an overall side view of the management work vehicle, FIG. 2 is a plan view of the same, and FIG. 3 is an explanatory diagram of power transmission. Body (1)
A front axle case (3) is provided at a front portion of a front body frame (1a) via a front case (2) so as to be capable of turning left and right.
The front wheel (4) is rotatably supported, and the engine (5) and the transmission case (6) are mounted on the rear part of the rear body frame (1b) forming the vehicle body (1). A pair of left and right rear wheels (9) are rotatably supported via an axle case (7) and a rear axle case (8). Further, a round steering handle (11) provided with a handle knob (11a) on the upper surface side of the step (10) on the upper side of the rear body frame (1b) and a driver's seat (12) are provided. ) Is erected and the sun visor (14) is attached, and the left and right armrests (15) are fixed on both sides of the driver's seat (12).
An HST main shift lever (16), a work implement elevating lever (17) and an accelerator lever (18) protruding from the right side of the steering column are provided on the right front, and a PTO is also provided on the right rear.
A lever (20) is provided, a fuel tank (19) is provided on the left side of the driver's seat (12), and an auxiliary traveling speed change lever (21) is further provided on the front side of the driver's seat (12). The traveling clutch pedal (22) is attached. The traveling drive force of the transmission case (6) is transmitted to the front wheels (4) by the front wheel drive shaft (23), and the HST main speed change lever (16) is operated to operate the front wheels (4) having a three-wheel structure and the left and right rear wheels ( 9) and the steering handle (11)
When the front wheel (4) is turned left and right by operation to change the traveling course, and when the steering angle of the steering handle (11) becomes larger than a certain value, the left and right side clutches (24)
The inside and outside of the turning of the vehicle are automatically turned off to stop driving of both rear wheels (9), and drive only one front wheel (4) to perform a U-turn or the like on a paddy field. .

A work machine (29) having a rotary pawl (27) and a cultivation plate (28) is provided by attaching a parallel link (26) by fixing a hitch (25) to the front lower side of the front body frame (1a). The work machine (29) is removably attached to the parallel link (26), and the work machine lift lever (17) is operated to raise and lower the work machine (29) to a working position or a non-working position by a hydraulic lifting cylinder (30). The PTO power of (6) is transmitted to the working machine (29) by the PTO shaft (31), and the rotary pawl (27) is driven to perform the medium tilling operation. In addition, various farming operations such as transplanting of vegetable seedlings or harvesting of vegetables are performed by exchanging various working machines such as a transplanting machine or a harvesting machine with the working machine (29).

[0007] A hydraulic stepless transmission (32) is provided in the transmission case (6), and the power of the engine (5) is transmitted by a belt (34) stretched through a tension roller type traveling clutch (33). 32), and a hydraulic pump (35) and a hydraulic motor (36) of the transmission (32).
The transmission case (6) is provided with a traveling brake (38) for inputting the transmission to the transmission case (6) after the gearshift, and for performing traveling braking by operating the brake arm (37).

Further, as shown in FIG. 4, a cylindrical kingpin (39) is rotatably supported on the front case (2), and a gear case (4) is provided below the kingpin (39).
0), the front axle case (3) is fixed, and the kingpin (39) is connected to the steering shaft (41) which is operated by the steering handle (11) in the forward / reverse direction. The kingpin (39) and the gear case (40) And a front wheel for integrally rotating the front axle case (3) about the axis of the kingpin (39) by forward / reverse rotation of the steering shaft (41), and supporting the front axle case (3) via the front axle (42). The front wheel drive shaft (23) is connected to the upper end of the input shaft (43) for loosely inserting the king pin (39) into the hollow while the (4) is turned left and right, and the gear case (40)
The lower end of the input shaft (43) is connected to the front axle (42) via a bevel gear (44) and the like to drive the front wheel (4) to travel, and the steering shaft (41) is connected to the king pin (39). When the worm (45) is decelerated, the front wheel (4) in the straight traveling position is turned left and right by about 90 degrees by three rotations of the steering handle (11).

Further, as shown in FIG. 5, a weight-type steering cam (50) having an arcuate surface symmetrically with respect to the center line of the body width is fixed to the king pin (39). ) Is provided with left and right cam floors (51), and left and right side clutch wires (5) are attached to left and right clutch levers (52).
3), the left and right cam floors (51) are connected to each other, and the front and rear wheels (4) are turned in the left and right directions by about 20 degrees or more.
1) is actuated, the side clutch wire (53) is pulled through the cam floor (51), the inner and outer side clutches (24) are disengaged by the clutch levers (52) on both sides, and the inner and outer rear wheels are turned. The driving of (9) is automatically stopped. In addition, since the illustrated weight-type steering cam (50) is provided with an arcuate surface symmetrically with respect to the body width center line,
The left and right side clutches (24) are configured to be simultaneously disengaged almost simultaneously when the steering angle increases by a certain amount or more, regardless of whether the turning of the steering handle (11) is in the left or right direction. Not something. Further, the switching arm (55) of the left and right side clutch pedals (46) is connected to the rear body frame (16) via the left and right lever fulcrum shafts (54).
And the side clutch (24) is disengaged by stepping on the pedal (46). Therefore, the operation of the left and right rear wheels (9) can be disconnected as required by operating the side clutch pedal (46). In addition, even if the steering handle interlocking mechanism for the side clutch (24) is not provided, the turning by driving only the front wheel (4) becomes possible by operating both side clutch pedals (46) during turning.

As described above, the direction change operation of the front wheel (4) operated by the steering handle (11) is detected, and the side clutch (24) of the inner and outer rear wheels (9) is automatically disengaged. A side clutch wire (53) serving as a side clutch disconnecting member is provided, and a left and right side clutch pedal (46) is connected in parallel with the side clutch wire (53) to a left and right clutch lever (52) for turning on and off the left and right side clutch (24). When the front wheels (4) are turned, the driving of both rear wheels (9) inside and outside of the turn is stopped by turning the direction of the front wheels (4), and only the front wheels (4) are driven to prevent the front wheels (4) from being pushed down. The turning radius of the car can be reduced.

A single front wheel (4) is mounted at the front center of the vehicle body (1), and a pair of left and right rear wheels (9) are mounted on both sides of the rear part of the vehicle body (1). A front wheel drive shaft (23) for driving the front wheel (4) is connected to the drive input side of the clutch (24), and the front wheel (4) is driven regardless of the drive state of the left and right rear wheels (9) to change direction. In addition to improving the driving operability, the left and right side clutch pedals (4) are located below the front of the driver's seat (12) where the operator sits.
6), and a side clutch pedal (46) is provided at a position away from a general position below the steering handle (11) to prevent misoperation as a brake pedal in a normal working state. This prevents the operator from recognizing and appropriately operating the side clutch pedal (46). The left and right side clutch pedals (46) extend in the width direction of the circular steering wheel (11) in front of the driver's seat (12). Are separated from each other to prevent erroneous operation due to erroneous recognition of the left and right side clutch pedals (46), and to stop while appropriately selecting the drive of the left and right rear wheels (9).

Further, a steering valve (47) switched by a steering handle (11) is provided, and a hydraulic pump (48) driven by an engine (5) and a lifting valve (49) for operating a lifting cylinder (30). The lifting valve (49) is hydraulically connected in series to the hydraulic pump (48) via the steering valve (47), and the steering valve (47) is switched by operating the steering handle (11) to steer. The motor (not shown) is rotated forward and reverse, and the output shaft is rotated in the same direction by the hydraulic pressure in the same direction by the rotation angle of the steering handle (11) to change the direction of the front wheel (4) left and right. The lifting valve (49) is switched by operating the lifting lever (17), and the lifting cylinder (30) is operated to raise and lower the work implement (29) between the front wheel (4) and the rear wheel (9).

As is apparent from the above configuration, the work implement (29) is mounted on the front of the vehicle body (1) via the link mechanism (26) and the lifting cylinder (30), and the driver's seat (12) and the steering are provided. In an administrative work vehicle in which a handle (11), an engine (5), and a transmission case (6) are attached to a rear part of a vehicle body (1), an elevating valve (9) for controlling an elevating cylinder (30) and a work implement elevating lever (17) Is provided at the rear of the vehicle body (1), and a link mechanism (2) at the front of the vehicle body (1) is provided.
6) and the lifting valve (49) at the rear of the vehicle body (1) are connected by a feedback wire (not shown), and the amount of vertical movement of the link mechanism (26) is detected by the feedback wire to return the lifting valve (49) to the neutral position. Then, the lifting amount of the work machine (29) is made to coincide with the operation amount of the lifting lever (17), thereby improving the lifting function of the working machine (29) and simplifying the lifting structure.

As described above, the working machine (29) is mounted on the front of the vehicle body via the link mechanism (26) and the elevating cylinder (30).
The driver's seat (12) and the steering wheel (1
1) In a maintenance work vehicle in which the engine (5) and the transmission case (6) are mounted on the rear of the vehicle body, when the steering angle of the steering handle (11) becomes larger than a certain value, a weight-type operation fixed to the king pin (39). Following the turning of the directional cam (50), the left and right cam floors (51) are operated substantially simultaneously,
Since the side clutches (24) of both rear wheels are disconnected via the left and right side clutch wires (53), the driving of both rear wheels (9) is stopped, and only one of the front wheels (4) is driven.
The turning radius of the work management vehicle is reduced, so that good steering performance is obtained and the driving operation is improved. Further, the side clutches (24) of both rear wheels are disconnected by operating both side clutch pedals (46), and a management work vehicle driven by only one front wheel (4) is obtained.

Next, a description will be given of modifications of the lifting mechanism of the working machine which is arranged on the abdomen between the front wheel and the rear wheel of the maintenance work vehicle described in the above embodiment so as to be able to move up and down. When the controlled work vehicle turns, the work machine is stored in the abdomen in the center of the machine and then turns, but due to an erroneous operation by the operator, the work vehicle is turned without storing the work machine, and the control work vehicle body or the work machine is damaged. There is a problem to do. In order to solve such a problem, after the work management vehicle has completed the work, when the vehicle shifts to the turning operation, when the steering angle or the angular velocity of the steering wheel (11) exceeds the specified value, the work machine is moved. It is configured as follows to accommodate.

That is, as shown in FIG. 6, a kingpin (39) connected to a steering shaft (41) that rotates forward and backward by a steering handle (11) is symmetrical with respect to the center line of the body width. A side clutch wire (53) fixed to a weight-type steering cam (50) provided with a weight and connected to a weight-type left and right cam floor (51) abutting on the cam (50).
A lifting / lowering operation clutch wire (57) is further connected to the same position, and the other end of the wire (57) is inserted through the case of the body of the body and connected to the middle of the lifting / lowering lever (17).

As is apparent from the above configuration, when the steering angle of the steering handle (11) of the control work vehicle becomes a predetermined angle or more, the cam floor (5) abutting on the weight-type cam (50).
1) is actuated, pulling the lifting operation clutch wire (57) through the cam floor (51), returning the lifting lever (17) connected to the wire (57) to the raised position,
Since the working machine (29) is raised to the non-working position and stored in the predetermined position, damage to the work management machine or the working machine due to erroneous operation by the operator is reliably prevented, and more efficient work is possible.

Next, when the control work vehicle is moved backward, the operator manually stores the work machine similarly to the turning operation, and then moves the work control vehicle backward. However, there is a fear that the management work vehicle and the work machine will be damaged if the work vehicle is moved backward without storing the work machine without following the above procedure when the management work vehicle moves backward. In order to solve such problems,
As shown in FIG. 7, an L-shaped lever return plate (16r) for forcibly moving the elevating lever (17) is provided at a substantially intermediate position of the HST main shift lever (16), and is perpendicular to the return plate (16r). The provided abutting piece (16t) is configured to abut on the working machine elevating lever (17) that is planted adjacently.

With the HST main shift lever (16) configured as described above shifted to the neutral position, the contact piece (16t) of the lever return plate (16r) contacts the work implement elevating lever (17). HST main shift lever (16)
Is shifted to the reverse position, the work implement elevating lever (17) shifted to the working position moves the lever return plate (1).
6r), the working machine is forcibly moved to the working machine raising position, that is, the non-working position, and the working machine (29) can be lifted via the hydraulic lifting cylinder (30). Thus, more efficient storage operation can be performed. Although the description has been given of the example of the return plate in which the lifting mechanism of the work machine is provided on the HST main shift lever, a rotation sensor is provided on the axle of the rear wheel, the sensor detects the backward movement of the axle, and outputs the output to the hydraulic pressure through the controller. It is also possible to drive the lifting cylinder to raise the working machine.

Next, the turning mechanism may be configured as follows. In a three-wheeled management vehicle with one wheel on the front wheel and two wheels on the rear wheel, simply turning off the drive of the rear wheel only inside the turn at the time of turning, pushing the soil by the front wheel, devastating the field scene,
Further, the turning radius becomes large, and there is a problem in the steering function or the driving operation.

Therefore, in order to solve these problems,
By changing the rotation speed of the front wheels according to the turning angle of the steering angle of the front wheels, and by setting so that the rotation speed of the front wheels does not change if the speed exceeds a certain speed while the managed vehicle is moving forward or backward. The turning mechanism is configured such that the turning radius is reduced, the pressing of the front wheel by the soil in the field scene is reduced, the safety of the steering is secured, and the sharp turning at high speed rotation is restricted.

The turning mechanism (A) will be described with reference to FIG. A planetary gear mechanism (71) and a transmission (72) having a high-speed rotation and a low-speed rotation gear are arranged on a steering shaft (41) that is rotated forward and backward by a steering handle (11). Since the transmission gear is configured to be transmitted to the gear of the front wheel drive shaft (23) in the front case (2), the steering angle of the steering wheel (11) (or the turning angle of the front wheel) is equal to or greater than a specified angle. Then, the gear meshing with the high-speed rotation side is switched to the low-speed rotation side gear to change the rotation speed of the front wheel (4), and the maintenance work vehicle can be operated while maintaining the low-speed rotation. . Note that a wire (73) is connected to a selector provided in the transmission (72).
, And one end of the wire (73) is connected to a turning operation lever (74) provided at an appropriate position on the driver's seat side, whereby the front wheel speed at the time of turning by manual operation can be changed.

The turning mechanism (B) will be described with reference to FIG. A cam (81) is fixed to the steering handle (41) of the steering shaft (41) that is rotated forward and backward by the steering handle (11).
An HST (82) is arranged adjacent to the cam (81),
The output side of the HST (82) is configured to be connected to the front wheel drive shaft (23). Thus, the steering axis (4
HST following the movement of the cam (81) fixed to 1)
The inclination angle of the swash plate of the hydraulic pump in (82) is changed,
ST (82) Since the driving force is transmitted to the front wheel drive shaft (23) connected to the output side, the rotation speed of the front wheel (4) is changed from high-speed rotation to low-speed rotation, and the low-speed rotation is performed. It is possible to operate the management work vehicle while maintaining the rotation. Further, as described in the turning mechanism (B), the manual operation is performed by connecting the wire (83) to the cam (81) fixed to the steering shaft (41) and connecting the wire (83) to the turning operation lever (84). , It is possible to change the front wheel speed at the time of turning.

As described above with reference to the turning mechanisms (A) and (B), the rotational speed of the front wheels is changed according to the turning angle of the steering angle of the front wheels. If the speed is exceeded, the turning radius is reduced by setting the front wheel rotation speed not to change,
This has the effect of reducing the pressing of the front wheels in the field scene, ensuring the safety of maneuvering, and restricting sharp turns at high speeds.

[0025]

As is apparent from the above embodiments, the work machine is mounted on the front of the vehicle body via the link mechanism and the lifting cylinder, and the driver's seat, the steering wheel, the engine and the transmission case are mounted on the rear of the vehicle body. In the working vehicle, according to the first aspect of the present invention, when turning, the side clutches of both rear wheels are disengaged and only one front wheel is driven, so the turning radius of the management work vehicle during turning is reduced, The operability of turning is improved. According to the second aspect, the side clutches of both rear wheels are disengaged when the steering angle of the steering wheel becomes larger than a predetermined value by the operation of the weight-type cam provided in the steering transmission unit. Since the side clutch is disengaged, only one operation of the steering wheel is required, so the side clutches of both rear wheels are disengaged accurately and reliably, the turning radius of the maintenance work vehicle is reduced, and turning with better operability is achieved. Is obtained. According to the third aspect of the present invention, the side clutches of both rear wheels are disengaged by operating both side clutch pedals and only one front wheel is driven. Is disconnected,
The turning radius of the maintenance work vehicle is reduced.

[Brief description of the drawings]

FIG. 1 is an overall side view of a passenger management machine.

FIG. 2 is an overall plan view of the passenger management machine.

FIG. 3 is an explanatory diagram of a power transmission system of the passenger management machine.

FIG. 4 is an explanatory view of a front wheel.

FIG. 5 is an explanatory view of a steering cam and a side clutch.

FIG. 6 is an explanatory view of a lifting mechanism of the working machine.

FIG. 7 is an explanatory view of an HST lever and a lifting lever.

FIG. 8 is an explanatory view of a modified example (A) of the turning mechanism.

FIG. 9 is an explanatory view of a modification (B) of the turning mechanism.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Body 1a Front body frame 1b Rear body frame 2 Front case 3 Front axle case 6 Transmission case 7 Axle case 8 Rear axle case 11 Steering handle 16 HST type main shift lever 16r Elevating lever return plate 16t Contact piece 17 Elevating lever 18 Accelerator Lever 20 PTO lever 26 Link mechanism 29 Work implement 31 PTO shaft 32 Hydraulic continuously variable transmission 46 Side clutch pedal 41 Steering axis 50 Weight type steering cam 51 Cam floor 53 Side clutch wire 57 Elevating operation clutch wire 71 Planetary gear mechanism 72 Shifting Device 73 Wire 74 Swivel control lever 81 Cam 82 HST 83 Wire 84 Swivel control lever

Claims (3)

[Claims] 1. A maintenance work vehicle in which a work machine is mounted on a front portion of a vehicle body via a link mechanism and a lifting cylinder and a driver's seat, a steering wheel, an engine, and a transmission case are mounted on a rear portion of the vehicle body. Disengaging the side clutch and driving only one front wheel. 2. The side clutches of the two rear wheels are disengaged by the operation of a weight-type cam provided in a steering operation transmitting portion when the steering angle of the steering wheel becomes larger than a predetermined value. The management work vehicle according to 1. 3. The maintenance work vehicle according to claim 1, wherein the side clutches of both rear wheels are disengaged by operating both side clutch pedals.