JP2000145906A - Working vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a working vehicle corresponding to a high-output engine, without damaging a lawn, and having superior workability. SOLUTION: Output from an engine 1 having high output, 15 HP or more, is transmitted through an automatic transmission 7 to a running driving system. The automatic transmission 7 has a primary pulley 27 for receiving the rotation of the engine 1, a secondary pulley 28 for outputting rotation to the running driving system, and a steel belt 29 stretched between the primary pulley 27 and the secondary pulley 28 and formed by nipping many pieces 40 made of steel on a steel band 41.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a working vehicle used for cutting grass, spraying dirt, and spreading fertilizer on a golf course, and more particularly to a working vehicle using a CVT as a power transmission device.

[0002]

2. Description of the Related Art Conventionally, in an autonomous traveling work vehicle used for mowing and spraying a liquid agent in a golf course or a garden, and various working vehicles such as a mower, a snow blower, and a construction machine, an engine and a motor are used. 2. Description of the Related Art A configuration for transmitting an output of a prime mover to a traveling drive system via a clutch and a transmission has been widely used.

[0003] In recent years, such a working vehicle has a hydrostatic continuously variable transmission or a belt-type continuously variable transmission in order to maximize the motor torque without overloading the motor due to load fluctuations caused by traveling uphill. Various types including a transmission have been proposed.

For example, Japanese Patent Laying-Open No. 5-302672 discloses an apparatus using a hydrostatic continuously variable transmission, in which the throttle opening is variably set according to the engine load during normal running. Is used to control the engine speed to maintain the rated speed. On the other hand, when the engine does not reach the rated rotation even when the throttle is fully opened, it is determined that the engine is overloaded and the pump flow rate of the hydrostatic continuously variable transmission is limited, thereby controlling the vehicle speed to reduce the speed and avoiding the engine overload. The rotation is returned to the rated operation.

[0005] Japanese Patent Application Laid-Open No. 5-65036 discloses that
One using a belt-type continuously variable transmission has been disclosed,
Here, a belt-type continuously variable transmission is interposed between the engine and the transmission, and the reduction ratio of the belt-type continuously variable transmission is variably set according to the load during traveling. At the same time, the vehicle speed is constantly detected, and when the vehicle speed changes according to the reduction ratio set by the belt-type continuously variable transmission, the throttle opening is adjusted to control the engine speed in a direction in which the vehicle speed becomes constant. ing.

[0006]

However, in a working vehicle using a manual transmission as described above, the wheels may idle due to sudden start or shift change due to a clutch operation error. For this reason, when such a work vehicle is used as a work vehicle for a golf course or a garden, for example, a situation such as scraping of the turf due to idling of wheels occurs, which is not preferable as a turf management vehicle.

[0007] On the other hand, the one provided with the continuously variable transmission,
Although no harm is caused by sudden start, etc., for example, in a vehicle equipped with a hydrostatic continuously variable transmission, there is a problem that the operation sound is loud due to cavitation and the like when the hydraulic pressure starts to rotate, and the quietness is lacking. .

[0008] Further, in the case of a vehicle equipped with a belt-type continuously variable transmission, which is superior to a hydrostatic continuously variable transmission in terms of quietness, conventionally, this type of working vehicle transmits power by a rubber belt. Since the device is used only in combination with a low horsepower engine, there is a problem that it is not possible to meet the demand for higher output.

SUMMARY OF THE INVENTION An object of the present invention is to provide a work vehicle which is compatible with a high-output engine and which is excellent in workability without harm such as damaging the turf.

[0010]

The work vehicle of the present invention comprises:
A traveling vehicle that transmits an output of a prime mover to a traveling drive system via an automatic transmission, wherein the automatic transmission is a belt-type continuously variable transmission that transmits power using a steel belt. .

As a result, a high output (for example, 15
(More than horsepower) can be used in combination with the CVT, and a comfortable working environment with a high-power engine can be realized while preventing damage to the turf due to idling of the drive wheels during sudden start or shift change.

Further, another working vehicle of the present invention is a traveling vehicle for transmitting an output of a prime mover to a traveling drive system via an automatic transmission, wherein the automatic transmission receives the rotation of the prime mover. A primary pulley, a secondary pulley that outputs rotation to the traveling drive system, and a bridge between the primary pulley and the secondary pulley,
And a steel belt formed by sandwiching a number of steel pieces with a steel band.

[0013] Thereby, a high output (for example, 15
(More than horsepower) can be used in combination with the CVT, and a comfortable working environment with a high-power engine can be realized while preventing damage to the turf due to idling of the drive wheels during sudden start or shift change.

Further, in these cases, it is possible to apply a motor having an output of 15 hp or more as the motor.

[0015]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is an explanatory diagram showing the overall configuration of a working vehicle according to an embodiment of the present invention.

The work vehicle according to the present embodiment is an autonomous traveling vehicle used, for example, for turf management at a golf course.
Spreading work such as fertilizer or soil can be performed while traveling on the grass. In this case, the working vehicle employs a so-called main engine system. As shown in FIG. 1, an engine (motor) 1 is disposed at the center, and the spreader 2 and the driving wheels 3 at the rear of the vehicle are arranged by the engine 1. It is designed to drive both.

Here, the spreader 2 is a working machine for spraying fertilizer, soil, etc. on grass, and is provided with a hopper 4 for accommodating fertilizer, soil, etc., which are to be sprayed. The spreader 2 is provided with a hydraulic motor 5 driven by the engine 1, and the hydraulic motor 5 drives a spraying device 6 disposed below the hopper 4. Then, fertilizers and the like are sprayed on the ground surface from a spray port (not shown) provided at a lower portion of the vehicle by the spray device 6.

In the working vehicle, the drive wheels 3 are driven by the engine 1 together with the spreader 2 as described above. FIG. 2 is an explanatory diagram showing an outline of a power transmission system of the work vehicle shown in FIG. As shown in FIG. 2, here, the output from the engine 1 is input to the automatic transmission 7 and transmitted to a traveling drive system such as a propeller shaft 8 therefrom.
The rotation of the propeller shaft 8 is transmitted to the drive wheels 3 via differential devices 9 provided at the front and rear of the vehicle, so that the vehicle travels.

At this time, in the working vehicle according to the present invention, a prime mover having an output of 20 hp (15 hp or more) is disposed in the engine 1, and the rotation thereof uses a steel belt type continuously variable transmission (CVT). The automatic transmission 7 is appropriately shifted. That is, in the present invention, a steel belt type CVT conventionally used for automobiles is applied to a work vehicle, and thereby a high horsepower engine is provided with a high gear ratio (i.
= About 5.0). Therefore,
The work vehicle uses a CVT to improve workability while preventing damage to the turf due to idling of the drive wheels 3 at the time of sudden start or shift change, and to realize a comfortable work environment by a high horsepower engine. Is possible.

On the other hand, the hydraulic motor 5 for driving the spreader 2 is supplied with hydraulic pressure via two hydraulic circuits.
That is, hydraulic pressure is supplied from the first hydraulic pump 11 driven by the rotation of the propeller shaft 8 and the second hydraulic pump 13 driven by the crankshaft of the engine 1. In this case, hydraulic pressure is supplied from the first hydraulic pump 11 via the first hydraulic circuit 12 and from the second hydraulic pump 13 via the second hydraulic circuit 14. Further, each of the hydraulic circuits 12 and 14 is provided with control valves 15 and 16 and check valves 17 and 18 operated by a spreader operation switch (not shown). And this control valve 1
The amount of oil supplied from the second hydraulic circuit 14 is about 1/3 to 1 of the total amount of oil supplied to the hydraulic
/ 4 has been adjusted.

The ratio can be appropriately changed from the outside by adjusting the opening of the control valves 15 and 16. The ratio is not limited to this, and is adjusted so that the amount of oil supplied from the second hydraulic circuit 14 is smaller than the amount of oil supplied from the first hydraulic circuit 12. Any ratio can be employed.

As described above, by supplying the hydraulic pressure to the hydraulic motor 5 by the first and second hydraulic pumps 11 and 13, not only the rotation of the engine 1 but also the oil amount corresponding to the vehicle speed V can be increased. Will be supplied. Therefore, even when the vehicle speed V changes due to the undulation of the ground, the operation of the spreader 2 can be changed by following the change. For this reason, even in a work such as a fertilizer or a chemical that needs to be sprayed uniformly on the ground surface, the spraying amount can be adjusted according to the vehicle speed V, and it is possible to avoid uneven distribution.

Next, the internal structure of the power transmission system in the working vehicle will be described. FIG. 3 is an explanatory diagram showing the internal configuration. As shown in FIG. 3, a torque converter 2 is provided on the left side (rear side of the vehicle) of the engine 1 in the figure.
2, a forward / reverse switching device 23 and a continuously variable transmission 24 are provided. The crankshaft 21 of the engine 1 is connected to a continuously variable transmission 24 via a torque converter 22 and a forward / reverse switching device 23. A second hydraulic pump 13 is disposed on the right side of the engine 1 in the drawing, and a right end side of the crankshaft 21 is connected to the second hydraulic pump 13.

The continuously variable transmission 24 has an input shaft 2
A primary pulley 27 and a secondary pulley 28, each having a variable groove width, are supported by the output shaft 5 and the output shaft 26, and a steel belt 29 is stretched between the pulleys 27 and 28. In this case, the steel belt 29
A large number of steel pieces 40 are sandwiched between steel bands 41 and formed. That is, here, unlike the rubber belt, the power is transmitted by the pressing force of the steel piece 40, so that the power of the high horsepower engine 1 can be smoothly transmitted to the secondary pulley 28. The output shaft 26 of the continuously variable transmission 24 is connected to the input gear 30 of the propeller shaft 8 via a final reduction gear group 35.

The primary pulley 27 and the secondary pulley 28 of the continuously variable transmission 24 have respective pulleys 27 and 2 respectively.
Hydraulic cylinders 31 and 32 for variably operating the groove width of No. 8 are continuously provided. The gear ratio of the continuously variable transmission 24 is controlled by appropriately adjusting the hydraulic pressure supplied to the hydraulic cylinders 31 and 32. That is, the primary pressure P _P is supplied to the hydraulic cylinder 31 of the primary pulley 27
Is decreased, the groove width of the primary pulley 27 increases, and the winding diameter of the steel belt 29 around the primary pulley 27 decreases. At the same time, the groove width of the secondary pulley 28 that is rotationally driven from the primary pulley 27 via the steel belt 29 decreases, and the winding diameter of the steel belt 29 around the secondary pulley 28 increases. As a result, the speed ratio of the continuously variable transmission 24 is increased and the speed is shifted to the low side.

[0026] Conversely, increasing the primary pressure P _P is supplied to the hydraulic cylinder 31, the primary pulley 2
7, the diameter of the winding of the steel belt 29 around the primary pulley 27 increases. At the same time, the groove width of the secondary pulley 28, which is rotationally driven from the primary pulley 27 via the steel belt 29, increases, and the steel belt 2
9 has a smaller winding diameter. As a result, the speed ratio of the continuously variable transmission 24 decreases, and the speed is shifted to the high side. In addition,
The line pressure P _L is supplied to the hydraulic cylinder 32 of the secondary pulley 28, and the line pressure P _L gives the secondary pulley 28 a pressing force capable of transmitting torque by contact with the steel belt 29.

On the other hand, the input gear 30 of the propeller shaft 8
, The power of the first hydraulic pump 11 is taken. That is, the input gear 30 meshes with the drive gear 34 provided on the drive shaft 33 of the first hydraulic pump 11,
The hydraulic pump 11 is driven in synchronization with the propeller shaft 8. Accordingly, the hydraulic pressure according to the vehicle speed V is supplied from the first hydraulic pump 11 to the hydraulic motor 5 via the first hydraulic circuit 12, whereby the spreader 2 is driven according to the vehicle speed V.

Further, the operation of the working vehicle according to the present invention will be described. First, when the engine 1 is driven, the crankshaft 21 rotates, and the second hydraulic pump 13 is driven together therewith. Thereby, the second hydraulic circuit 14
Is supplied to the hydraulic motor 5 via the control valve 15 and the check valve 17. In this case, the hydraulic pressure supplied from the second hydraulic pump 13 at the time of engine idling (for example, 1200 rpm)
Approximately 1/3 of the rated value, but sufficient hydraulic pressure is secured for the test operation of the spreader 2. Therefore, in the working vehicle, if the spreader operation switch is turned on at the start of the work, the hydraulic pressure is supplied to the hydraulic motor 5 and the spreader 2 is operated, and the operation can be checked in advance. Further, even when the vehicle is stopped, the hydraulic pressure is supplied to the hydraulic motor 5, so that the operation of the spreader 2 can be checked by stopping the vehicle during the work.

Next, when the forward / reverse switching device 23 is switched from the neutral position to the forward (or reverse) side, the continuously variable transmission 2
The engine rotation is transmitted to the input shaft 25 of No. 4 and the primary pulley 27 rotates. The rotation of the primary pulley 27 is controlled by the steel belt 29 and the secondary pulley 28 is rotated.
To the final reduction gear group 35 from the output shaft 26.
Through the input gear 30 of the propeller shaft 8. As a result, the propeller shaft 8 is driven, and the drive wheels 3 are rotated via the differential device 9 so that the vehicle travels.

The rotation of the input gear 30 is further transmitted to the drive shaft 33 of the first hydraulic pump 11 via the drive gear 34. Therefore, the first hydraulic pump 11 is driven in synchronization with the propeller shaft 8, and the first hydraulic pump 11 supplies an oil amount corresponding to the vehicle speed V to the hydraulic motor 5.

On the other hand, when the vehicle is started by switching the forward / reverse switching device 23 and then the accelerator (not shown) is depressed to increase the engine speed, the vehicle speed V increases accordingly. In this case, the vehicle speed V, by appropriately controlling the primary pressure P _P of the continuously variable transmission 24 according to the load, changing appropriately the speed thereof changed by the pulley operates as described above. At this time, in the working vehicle, a CVT using a steel belt 29 is used as the continuously variable transmission 24, and a high horsepower (15 or more horsepower) engine and a CVT can be used in combination. Therefore, in the work vehicle, work can be performed while preventing damage to the turf due to idling of the drive wheels 3, and the speed ratio can be set high, thereby improving operability. It becomes possible. Furthermore, since a high-output engine can be used, even in a main engine type working vehicle that obtains the driving force of the working machine from the engine, there is a margin in the supply power, and it is possible to improve the traveling performance and workability. Become.

Further, as the vehicle speed V increases, the hydraulic pressure supplied from the first hydraulic pump 11 also increases, and the output of the hydraulic motor 5 also increases. In this case, the hydraulic pressure supplied from the second hydraulic pump 13 also increases as the rotational speed of the engine 1 increases, but the supply hydraulic pressure from the first hydraulic pump 11 increases more than the hydraulic pressure supplied from the second hydraulic pump 13. Therefore, the output of the hydraulic motor 5 changes substantially in accordance with the vehicle speed V. Therefore, when the spreader operation switch is turned on, the soil or the like in an amount corresponding to the vehicle speed V is sprayed.

FIG. 4 is an explanatory diagram showing the relationship between the vehicle speed V and the operating speed N _S of the spreader 2. As shown in FIG. 4, when the vehicle speed V = 0 (when stopped), the spreader 2 rotates at the initial rotational speed N _S0 by the hydraulic pressure supplied from the second hydraulic pump 13 by idling of the engine 1. Then, at this time, the operation check of the spreader 2 can be performed as described above. Next, when the vehicle is traveling, the engine rotational speed N _E is increased (1200~3600rpm) according to the throttle opening degree, the vehicle speed V also increases. At the time of actual traveling, the vehicle speed V is appropriately changed by the operation of the continuously variable transmission 24 according to the load.

When the vehicle speed V increases in this manner, the operating speed N _S of the spreader 2 also increases as shown in FIG. At this time, the amount of change in the engine rotational speed N _E is less than the amount of change in vehicle speed V, the further hydraulic pressure supplied from the first hydraulic pump 11 is compared with the hydraulic pressure from the second hydraulic pump 13 2 3 times. For this reason, the operating speed N _S of the spreader 2 changes exclusively according to the vehicle speed V as shown in the figure.

That is, when the vehicle approaches the uphill section and the vehicle speed V decreases due to the operation of the continuously variable transmission 24,
The operating speed N _S of the spreader 2 also decreases accordingly.
The amount of sprinkled soil is also reduced. On the other hand, when the vehicle approaches the downhill section, the vehicle speed V
Increases, the operating rotational speed N _S of the spreader 2 also increases accordingly, and the amount of sprinkling of the soil and the like increases. Therefore, in the working vehicle, even if the vehicle speed V changes, the amount of sprinkling of the soil and the like automatically changes in accordance with the change of the vehicle speed V, whereby the soil and the like can be evenly sprayed per unit area.

As described above, it is also possible to check the operation status of the spreader 2 during the operation. That is,
When the vehicle is once stopped and the spreader operation switch is turned on, hydraulic pressure is supplied from the second hydraulic pump 13 to the hydraulic motor 5 by idling of the engine 1. Accordingly, this allows the spreader 2 to operate and check its operation.

It should be noted that the present invention is not limited to the above-described embodiment, but can be variously modified without departing from the gist thereof.

For example, the working vehicle in the above-described embodiment has a 4WD configuration in which the front and rear wheels are driven together, but a 2WD system in which only the front wheels or the rear wheels are driven may be employed. Although the engine 1 is also configured to change its rotation speed by a throttle operation, the engine rotation speed may be fixed. Further, the output and the number of revolutions of the engine 1 are not limited to those described above.
It goes without saying that various output values can be adopted.

In addition, an example has been shown in which the spreader 2 is used as a working machine to spray fertilizers and soil, but the working mode is not limited to this, and spraying liquids (disinfectants, pesticides), mowing, and tilling. The present invention can be applied to various work vehicles such as planting (rice planting, sowing seeds, etc.), harvesting, or aerator work, lifting and lowering of a work table, blower work, material transportation, and the like. Also,
The work target is not limited to a golf course, and can be widely applied as an off-road work vehicle such as a garden or farmland.

[0040]

According to the working vehicle of the present invention, the steel belt type CVT is used for the automatic transmission for transmitting the output of the prime mover to the traveling drive system. It is possible to realize a comfortable working environment with a high-power engine while preventing such problems. Therefore, it is possible to prevent damage to the turf due to idling, and it is possible to improve the operability since a high gear ratio can be obtained. In addition, since a high-power engine can be used, a main engine type working vehicle that obtains the driving force of the working machine from the engine can provide a margin in the supply power and improve the traveling performance and workability. Becomes possible.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an overall configuration of a working vehicle according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an outline of a power transmission system of the work vehicle in FIG.

FIG. 3 is an explanatory diagram showing an internal configuration of a power transmission system of the working vehicle in FIG. 1;

FIG. 4 is an explanatory diagram showing a relationship between a vehicle speed and an operation speed of a spreader.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine (motor) 2 Spreader 3 Drive wheel 5 Hydraulic motor 7 Automatic transmission 24 Continuously variable transmission 27 Primary pulley 28 Secondary pulley 29 Steel belt 40 Steel piece 41 Steel band

Claims (3)

[Claims] 1. A traveling vehicle that transmits an output of a prime mover to a traveling drive system via an automatic transmission, wherein the automatic transmission is a belt-type continuously variable transmission that transmits power using a steel belt. A work vehicle characterized by the above-mentioned. 2. A traveling vehicle that transmits an output of a prime mover to a traveling drive system via an automatic transmission, wherein the automatic transmission includes a primary pulley to which the rotation of the prime mover is input, and a traveling drive system. A secondary pulley that outputs rotation, and a steel belt that is bridged between the primary pulley and the secondary pulley and that is formed by sandwiching a number of steel pieces with a steel band. A working vehicle characterized by: 3. The work vehicle according to claim 1, wherein the output of the prime mover is 15 horsepower or more.