JP2022134334A - work vehicle - Google Patents

Abstract

To further increase the tractive force of a vehicle body in the case of performing working travel without deteriorating convenience in use during turning travel, transportation, or the like.SOLUTION: A work vehicle includes: a front weight 42 provided at the front end part of a body frame 1; a support mechanism 46 which supports the front weight 42 in such a manner that a position can be changed in a front-back direction relative to the body frame 1; and drive operation means 53 which can be operated to change the position of the front weight 42 in the front-back direction relative to the body frame 1 between a back side position close to the body frame 1 and a front side position far from the body frame 1.SELECTED DRAWING: Figure 5

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a work vehicle having a front weight on the front part of the body.

Conventionally, in the work vehicle configured as described above, a bracket for supporting the weight is fixed to the front end portion of the body frame, and the front weight is supported by the bracket (see, for example, Patent Document 1).

JP 2014-205368 A

In this type of work vehicle, a working device is connected to the rear part of the machine body to perform ground work. In this configuration, the front-rear weight balance of the vehicle tends to be rear-heavy. Therefore, by providing a front weight at the front end of the fuselage, the front-rear weight balance is improved and the propulsive force from the front wheels is increased during work travel. It is secured to increase the traction force of the vehicle body.

In order to further increase the tractive force of the vehicle body as described above, it is preferable to increase the added weight on the front side by the front weight. In order to increase the added weight in this way, it is conceivable to use a large front weight, or to arrange the front weight so that the center of gravity of the front weight is shifted toward the front of the fuselage.

However, in the improved configuration as described above, the front weight protrudes greatly toward the front side, and the longitudinal length of the fuselage becomes long. As a result, when turning before a ridge in a field, the front weight protruding forward is more likely to come into contact with the ridge. may decrease. In addition, when loaded on a truck or the like and transported, the longitudinal length of the machine body becomes long, so there is a disadvantage that it cannot be loaded on a small truck.

Therefore, it has been demanded to further increase the tractive force of the vehicle body when traveling for work without reducing the convenience of use during turning traveling or transportation.

A working vehicle according to the present invention is characterized by a front weight provided at the front end of a machine body frame, a support mechanism that supports the front weight so that the position of the front weight can be changed in the longitudinal direction with respect to the machine body frame, and the machine body frame. driving operation means capable of changing the longitudinal position of the front weight relative to the body frame between a rear position close to the body frame and a front position spaced apart from the body frame.

According to the present invention, for example, when traveling while working on the ground in a field, the driving operation means is operated to change the position of the front weight to the front side position, so that the front weight does not need to be large. The center of gravity position of the front weight can be moved to the front side of the fuselage. As a result, the tractive force of the vehicle body can be further increased.

On the other hand, when turning around near the edge of a ridge, or when loading and transporting on a truck or the like, the driving operation means is operated to change the position of the front weight to the rear side position, so that the front weight moves forward. By reducing the amount of protrusion of the fuselage, the longitudinal length of the fuselage can be shortened. As a result, it is possible to reduce the risk of the front weight coming into contact with the ridge, thereby improving work efficiency.

Therefore, it has become possible to further increase the tractive force of the vehicle body when traveling for work without deteriorating convenience in use during turning traveling, transportation, or the like.

In the present invention, the support mechanism includes a support rod extending in the longitudinal direction and movable in the longitudinal direction integrally with the front weight while supporting the load of the front weight; and a sliding support portion provided to slidably support the support rod in the front-rear direction.

According to this configuration, the position of the front weight in the front-rear direction can be changed by sliding the support rod in the front-rear direction while supporting the load of the front weight. Since the support rod is supported by the body frame via the sliding support portion, it is possible to smoothly move the front weight, which has a large load, while firmly supporting it.

In the present invention, it is preferable that the support rods and the sliding support portions are provided on both left and right sides of the body frame.

According to this configuration, since the support rods are slidably guided on both the left and right sides of the body frame, the front weight can be stably supported in a state of being both supported by the left and right support rods.

In the present invention, it is preferable that a bracket for supporting the front weight is connected to the front end of the support rod, and the front weight is detachably supported by the bracket.

According to this configuration, since the front weight can be attached to and detached from the bracket, the front weight can be removed when, for example, the front weight is not required depending on the work situation. The front weight can be replaced with a front weight having a different weight depending on the user's needs.

In the present invention, it is preferable that the driving operation means is composed of a hydraulic cylinder.

According to this configuration, the heavy front weight can be accurately moved in the front-rear direction by using the hydraulic cylinder having a large operating force.

1 is a side view of a tractor; FIG. 1 is a plan view of a tractor; FIG. 1 is a schematic configuration diagram showing a steering device; FIG. It is the schematic which shows the operation structure of a transmission switching device and a side brake. FIG. 4 is a perspective view showing a structure for supporting a front weight; FIG. 4 is a cross-sectional plan view showing the support arrangement for the front weights in the rear position; FIG. 4 is a cross-sectional plan view showing the support arrangement for the front weights in the forward position; It is a control block diagram. 4 is a flow chart of turning control; 4 is a flowchart of weight position change control; FIG. 4 is a diagram showing a turning angle for determining a turning state;

A case where the embodiment of the present invention is applied to a tractor, which is an example of a work vehicle, will be described with reference to the drawings. In the following explanation, the direction of the arrow "F" is the "front side of the aircraft" (see FIGS. 1 and 2), the direction of the arrow "B" is the "back side of the aircraft" (see FIGS. 1 and 2), and the direction of the arrow " The direction of the arrow "L" is defined as the "left side of the fuselage" (see FIG. 2), and the direction of the arrow "R" is defined as the "right side of the fuselage" (see FIG. 2).

As shown in FIGS. 1 and 2, this tractor includes a body frame 1 that supports the entire vehicle body, and the body frame 1 is supported by a pair of left and right front wheels 2 and a pair of left and right rear wheels 3 . A driving unit 4 is provided in the front part of the vehicle body, and a driving part 5 is provided in the front-rear middle part of the vehicle body. The body frame 1 is configured by integrally connecting a front frame 6, a clutch housing 7, and a transmission case 8 from the front side. A driving unit 4 is supported by the front frame 6 .

The driving unit 4 is provided with an engine 9 and various devices related to the engine 9 such as a radiator 10 for cooling the engine. A bonnet 11 that can be opened and closed surrounds the drive unit 4 . The power from the engine 9 is transmitted to the front wheels 2 and the rear wheels 3 through a traveling transmission system including a transmission for traveling (not shown) installed in the transmission case 8 that constitutes the body frame 1. It is Further, the driving section 5 is provided with a driver's seat 12 and an operating section 13 in front of the driver's seat 12 . The control unit 13 is provided with a control handle 14 and other control tools.

At the rear of the mission case 8, a pair of left and right lift arms 16 that are driven to swing vertically by the operation of hydraulic lifting cylinders 15 installed in the upper part of the mission case 8, and the power of the engine 9 can be extracted to the outside. A power take-off shaft (not shown) and the like are provided. The power take-off shaft is connected to the engine 9 via a work transmission system including a work transmission (not shown) and a work clutch (not shown) that are separate from the travel transmission system installed in the mission case 8. Power is transmitted from The left and right lift arms 16 are connected to a link mechanism 17 which is connected to the rear part of the transmission case 8 so as to be able to swing up and down. A transmission shaft or the like for transmitting power to a working device (not shown) is connected.

(Steering device)
A steering device ST that can switch the steering state of the front wheels 2 by operating the steering handle 14 is provided. As shown in FIG. 3 , the steering device ST includes a hydraulic steering cylinder 18 , an operation valve 19 and a power steering pump 20 . A steering cylinder 18 is interlocked with the knuckle arms 2 a of the left and right front wheels 2 , and is connected via an operation valve 19 to a hydraulic pump 21 interlocked with the engine 9 . A power steering pump 20 is connected to the operation valve 19 , and an input shaft 20 a of the power steering pump 20 is interlocked with an operation shaft 14 a of the steering handle 14 .

Accordingly, when the steering handle 14 is operated to rotate the input shaft 20a of the power steering pump 20, the operation valve 19 is operated according to the operation amount of the input shaft 20a, and pressure oil is supplied from the operation valve 19 to the steering cylinder 18. By operating the steering cylinder 18, the left and right front wheels 2 are steered in the steering direction corresponding to the rotation direction of the steering wheel 14, and the knuckle arms 2a are steered at a turning angle corresponding to the amount of operation of the input shaft 20a of the power steering pump 20. to operate by swinging. A steering angle sensor 22 for detecting a steering angle corresponding to a steering angle of the front wheels 2 from a straight-ahead state is provided at the swinging fulcrum of the knuckle arm 2a.

In this tractor, the driving modes are a four-wheel drive mode in which the front wheels 2 and the rear wheels 3 are driven at the same peripheral speed, a two-wheel drive mode in which only the left and right rear wheels 3 are driven, and a straight driving mode in which the front wheels 2 and the rear wheels are driven. 3 are driven at the same peripheral speed, but during cornering, the peripheral speed of the front wheels 2 is switched to a front wheel acceleration state in which the peripheral speed of the front wheels 2 is faster (twice) than that of the rear wheels 3; In addition to switching to the front wheel 2 acceleration state in which the peripheral speed of the front wheels 2 is faster (approximately twice) than the peripheral speed of the rear wheels 3 during turning, the rear wheels 3 on the inner side of the turn are suddenly braked. It is configured to be switchable between each of the turning modes. The running mode is switched by a running mode setter 23 (see FIG. 7) provided in the control section 13. FIG.

(Front wheel speed increasing device)
The front wheel speed increasing device 24 that can be switched to the front wheel speed increasing state will be described.
As shown in FIG. 4, a transmission switching device 25 provided in a transmission system for the front wheels 2 is provided with a first clutch 26 and a second clutch 27 for connecting and disconnecting power transmission to the left and right front wheels 2. When the clutch 26 is in a transmission state, power is transmitted through the first transmission mechanism 28, and the left and right front wheels 2 are rotationally driven so that the peripheral speeds of the left and right rear wheels 3 are substantially the same. When the second clutch 27 is in the transmission state, power is transmitted through the second transmission mechanism 29, and the peripheral speed of the left and right front wheels 2 is increased to approximately twice the peripheral speed of the left and right rear wheels 3. fast driven.

Hydraulic oil for the first and second clutches 26 and 27 is supplied from the hydraulic pump 21, and the supply state is switched by a front wheel acceleration switching valve 30, which is a three-position switching type electromagnetic valve. As will be described later, the operation of the front wheel speed increasing switching valve 30 is controlled by the control device 31 . The control device 31 is configured with a microcomputer and can control operations of a plurality of devices according to a preset control program.

(side brake)
Left and right side brakes 32 for braking the left and right rear wheels 3 separately are provided on the left and right sides of the transmission case 8 . As shown in FIG. 4 , the left and right side brakes 32 are separately linked to a pair of left and right brake pedals 33 arranged at the foot of the driving section 5 via brake cylinders 34 and linking rods 35 . . Thus, by depressing the left and right brake pedals 33 , the corresponding rear wheels 3 are braked with a braking force corresponding to the depressing operation amount of the brake pedals 33 .

The left and right brake cylinders 34 are composed of single-acting hydraulic cylinders. Hydraulic oil is supplied from the hydraulic pump 21 and the supply state is switched by a three-position switching type electromagnetic brake switching valve 36 . By operating the brake switching valve 36, the left and right brake cylinders 34 can be shortened separately, and the left and right side brakes 32 can be operated separately to the braking side. As a result, even when the brake pedal 33 is not depressed, the right or left side brake 32 can be operated to the braking side by operating the brake switching valve 36 .

As shown in FIG. 8, the control device 31 includes a front wheel speed increasing switching valve 30 and a brake switching valve 36 according to the set driving mode based on the detection information from the driving mode setter 23, the steering angle sensor 22, and the like. A swing control means 100 is provided in the form of a control program for controlling the operation of the .

In the four-wheel drive mode, the turning control means 100 switches the front wheel acceleration switching valve 30 to the front wheel acceleration state to drive the left and right front wheels 2 and the left and right rear wheels 3 at a constant speed. In the mode, power transmission to the front wheels 2 is cut off and only the rear wheels 3 are driven. Further, when either the small turning mode or the sharp turning mode is set, the driving state is switched to the driving state corresponding to the mode during turning traveling.

For example, the four-wheel drive mode is set when traveling in a field, and the two-wheel drive mode is set when traveling on a road. Further, the small turning mode is set when turning in a small turn in a field, and the sharp turning mode is set when it is necessary to make a turn after approaching the ridge as much as possible at the edge of a ridge.

Next, the control operation by the turning control means 100 will be described.
As shown in FIG. 9, in a state where either the small turning mode or the sharp turning mode is set as the driving mode (step #1), the turning angle of the front wheels 2 is detected based on the detection result of the turning angle sensor 22. is equal to or greater than a first predetermined angle α1 (see FIG. 11) (step #2), the lift switching valve 37 is actuated for the hydraulic lift cylinder 15 so as to lift the lift arm 16. is controlled (step #3). As a result, a working device (not shown) connected to the rear part of the machine body is largely raised. When the steering angle becomes equal to or greater than a second predetermined angle β1, which is set to be greater than the first predetermined angle α1 (step #4), the front wheel speed increasing switching valve is opened so that the second clutch 27 of the front wheel speed increasing device 24 is in the transmission state. 30 is operated to switch to the front wheel acceleration state (step #5). Further, at that time, if the steep turning mode is set, the brake switching valve 36 is operated to brake the side brake 32 on the inner side of the turning (steps #6, #7).

(machine frame)
As shown in FIG. 5 , the body frame 1 includes a pair of left and right front frames 6 extending in the longitudinal direction of the vehicle body at the front side of the body at intervals in the lateral width direction of the vehicle body. The left and right front frames 6 are formed in the shape of vertically oriented strip plates having a small width in the width direction of the vehicle body and a predetermined width along the vertical direction. The front ends of the left and right front frames 6 are connected to each other by a plate-shaped first connection frame 38 . The first connecting frame 38 has a small width in the longitudinal direction, has a width extending over the left and right front frames 6 in the width direction of the vehicle body, and has substantially the same width as the left and right front frames 6 in the vertical direction. is formed in a strip shape.

A plate-like second connecting frame 39 is provided at a front-rear middle position of the left and right front frames 6 to connect them. The second connecting frame 39 is shaped like a plate having a small width in the front-rear direction, a width extending over the left and right front frames 6 in the vehicle body width direction, and a narrower width than the left and right front frames 6 in the vertical direction. formed.

A bottom plate frame 40 is provided that connects the lower end portions of the left and right front frames 6 at the front-rear intermediate positions. A pair of front and rear bottom plate frames 40 are provided at positions spaced apart in the front-rear direction. The bottom plate frame 40 is formed in a lateral posture having a predetermined width along the front-rear direction. The front and rear bottom plate frames 40 are supported by a cylindrical front axle case 41 that is positioned below the front frame 6 and connects the left and right front wheels 2 . In this manner, the body frame 1 has a plurality of members connected in a frame shape to increase the rigidity.

(front weight)
As shown in FIGS. 1, 2 and 5, a front weight 42 is provided at the front end of the body frame 1 . A weight support 43 as a bracket for supporting the front weight 42 is provided at the front end of the front frame 6 of the body frame 1 . The weight support body 43 is formed on the front side of the bonnet 11 and has a shape extending in the vertical direction and the width direction of the vehicle body.

The weight support 43 has a shape in which a plate-like member extends like a frame in a plan view. The rear side portion 43A and the left and right lateral side portions 43B are formed by bending a continuous belt plate. A strip plate-like body is connected across the front end portions of the left and right lateral portions 43B to form a front portion 43C. The front side portion 43C and the rear side portion 43A have a plate surface parallel to the front surface of the first connection frame 38 and have substantially the same width as the first connection frame 38 . An intermediate reinforcement 43D is provided extending across the front side 43C and the rear side 43A at the laterally intermediate portion.

When the upper engaging portion 44 of the front weight 42 is engaged with the upper end of the front side portion 43C of the weight support 43, the load of the front weight 42 pushes the front side portion 43C toward the front side. Even if the engagement portion 45 on the lower side of the front weight 42 is engaged with the lower end of the front side portion 43C from below, the front weight 42 is prevented from moving upward even if a force acts to move it upward due to vibration of the fuselage or the like. is configured to be supported in such a way that it does not come off.

A support mechanism 46 that supports the front weight 42 so as to be able to change its position in the longitudinal direction with respect to the body frame 1, and the position of the front weight 42 in the longitudinal direction with respect to the body frame 1 is set to the rear side position close to the body frame 1 and the body frame 1. and a hydraulic weight operation cylinder 53 as a drive operation means that can be changed between a front position spaced from the .

As shown in FIGS. 5 and 6, the support mechanism 46 includes a support rod 47 that extends in the front-rear direction and is movable in the front-rear direction integrally with the front weight 42 while supporting the load of the front weight 42 . , and a sliding support portion 48 that is provided on the body frame 1 and supports the support rod 47 so as to be slidable in the longitudinal direction.

The sliding support portions 48 are attached to the lateral outer surfaces of the left and right front frames 6 so as to be integrally fixed. The left and right sliding support portions 48 each include a front support 49 and a rear support 50 spaced from the front support 49 in the front-rear direction. Insertion holes 51 through which the support rods 47 are slidably inserted in the front-rear direction are formed in the front support member 49 and the rear support member 50 .

Front end portions of the left and right support rods 47 are integrally connected to the rear side portion 43A of the weight support body 43 . A weight operating cylinder 53 is provided between the first connecting frame 38 and the second connecting frame 39 so as to extend in the front-rear direction.

The weight operating cylinder 53 is pivotally connected to a support bracket 54 fixed to the second connecting frame 39 at the rear end of the cylinder tube 53A so as to be able to swing about the horizontal axis. A cylinder rod 53B of the weight operating cylinder 53 extends forward of the machine body through an insertion hole 55 formed in the first connecting frame 38 . The tip of the cylinder rod 53B is interlocked with the rear portion 43A of the weight support 43 so as to move integrally in the front-rear direction.

As shown in FIGS. 6 and 7, the hydraulic oil to the weight operating cylinder 53 is supplied from the hydraulic pump 21, and the supply state is switched by the weight switching valve 56, which is a three-position switching type electromagnetic valve. As shown in FIG. 8 , the operation of the weight switching valve 56 is controlled by the controller 31 .

By extending and retracting the weight operation cylinder 53, the longitudinal position of the front weight 42 with respect to the body frame 1 is changed from the rear position (see FIG. 6) close to the body frame 1 to the front position away from the body frame 1 (see FIG. 6). 7). The front weight 42 can slide in the front-rear direction while the load is supported by the left and right support rods 47 .

(Weight position change control)
The control device 31 includes turning state determining means 101 for determining whether or not the vehicle body is in a turning state, and when the turning state determining means 101 determines the turning state, the front weights 42 are positioned at the rear side. A position control means 102 for controlling the operation of the weight operating cylinder 53 is provided in the form of a sorting program.

As shown in FIG. 8, a weight mode setter 57 as a mode switching means for switching the control mode of the position control means 102 between the automatic mode and the manual mode, and a manual operation for operating the weight operation cylinder 53 based on the manual operation. A manual weight switch 58 is provided as a tool.

Next, the control operation by the position control means 102 will be explained.
As shown in FIG. 10, if the automatic mode is set, the position control means 102 determines whether or not the vehicle body is in a turning state (step #11). For example, when the turning state is determined by determining whether or not the steering angle of the front wheels 2 is greater than or equal to a first predetermined angle α1 based on the detection result of the steering angle sensor 22 (step #12), the front weights 42 are The operation of the weight operating cylinder 53 is controlled so that it is in the rear position (step #13). If the turning state is not determined, the operation of the weight operating cylinder 53 is controlled so that the front weight 42 is positioned at the front side (step #14).

When the manual mode is set, the operation of the weight operation cylinder 53 is controlled so that the longitudinal position of the front weight 42 is changed based on the operation of the weight manual switch 58 regardless of the result of the turning state determination. (Steps #15, #16, #17).

In this configuration, the front weight 42 is maintained at the front side position and the center of gravity of the front weight 42 is shifted to the front side of the machine body when the machine is traveling straight for work in the field. As a result, the additional weight on the front side by the front weight 42 can be increased, and the tractive force of the vehicle body can be increased.

On the other hand, in the case of a sharp turn toward the next work stroke on the headland of the ridge, the front weight 42 can be automatically changed to the rear position, and the front weight 42 comes into contact with the ridge or the like. It is possible to make the turn in a state as close to the ridge as possible while reducing the risk of the vehicle falling. Also, in a non-working state such as when traveling on the road, the front weight 42 is always held at the rear position, so that the longitudinal length of the fuselage can be shortened.

[Another embodiment]
(1) In the above embodiment, the support mechanism 46 includes the support rod 47 and the sliding support portion 48, and the support rod 47 and the sliding support portion 48 are provided on both the left and right sides of the body frame 1, respectively. However, instead of this configuration, only one set of the support rod 47 and the sliding support portion 48 may be provided at the left and right center portions, or a configuration in which the front weight 42 is moved using a parallel link mechanism, Various mechanisms can be used, such as using a swing arm to reposition between front and rear positions.

(2) In the above embodiment, the weight support 43 (bracket) is connected to the front end of the support rod 47, and the front weight 42 is detachably supported by the weight support 43. Alternatively, the front weight 42 may be attached to the weight support 43 in a fixed state, or the front weight 42 may be attached to the support rod 47 in a fixed state.

(3) In the above embodiment, the driving operation means is composed of the weight operation cylinder 53, which is a hydraulic cylinder. , various configurations of the drive can be used.

(4) In the above embodiment, the tractor equipped with the front wheels 2 and the rear wheels 3 as the traveling device was exemplified. The same can be applied to a tractor equipped with a traveling device (not shown).

(5) In the above embodiment, a tractor is used as an example of a work vehicle, but the present invention can be applied to other work vehicles, such as a riding rice transplanter and a multi-purpose paddy field work vehicle.

INDUSTRIAL APPLICABILITY The present invention can be applied to a work vehicle having a front weight at the front of the body.

1 body frame 42 front weight 43 bracket 47 support rod 48 sliding support portion 53 drive operation means

Claims (5)

A front weight provided at the front end of the fuselage frame,
a support mechanism that supports the front weight so that the position of the front weight can be changed in the longitudinal direction with respect to the body frame;
a driving operation means capable of changing the longitudinal position of the front weight with respect to the body frame between a rear position close to the body frame and a front position spaced apart from the body frame. The support mechanism is
a support rod extending in the front-rear direction and movable in the front-rear direction integrally with the front weight while supporting the load of the front weight;
2. The working vehicle according to claim 1, further comprising: a sliding support portion provided on the body frame and supporting the support rod so as to be slidable in the front-rear direction. The work vehicle according to claim 2, wherein the support rods and the sliding support portions are provided on both left and right sides of the body frame. A bracket that supports the front weight is connected to the front end of the support rod,
The work vehicle according to claim 2 or 3, wherein the front weight is detachably supported by the bracket. 5. The work vehicle according to any one of claims 1 to 4, wherein the driving operation means is composed of a hydraulic cylinder.

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