JPH11291781A - Front wheel driving device for work vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form up a device compactly as much as possible, restrain parts from being increased in number when a gear type transmission and a hydraulic transmission are simultaneously mounted to an agricultural tractor and the like so as to allow each front wheel to be driven because a transmission will be complex in constitution, and because a mission case housing the aforesaid parts will be large in size. SOLUTION: A hydraulic pump 6 is provided for the side part of an engine, and a hydraulic motor 8 capable of being rotated by means of pressured oil received from the hydraulic pump 6, is provided for a front axle case 7 supporting each front wheel in such a way as to be freely rolled. And the output shaft 28 of the hydraulic pump 6 and power from a gear type transmission are transmitted to the ring rear 9 of a front wheel differential device in the inside of the case 7 so as to be meshed with the a rotating front wheel driving transmission shaft 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a working vehicle for agriculture, construction, or transportation, and more particularly, to a structure of a front wheel driving device of a working vehicle for driving front wheels.

[0002]

2. Description of the Related Art Conventionally, a working vehicle has a four-wheel drive configuration in which front and rear wheels are driven according to the conditions of various workplaces to travel. For example, the agricultural tractor sequentially transmits the rotational power output from the engine to the main clutch and the gear type transmission in the rear of the vehicle body,
The rotational power output from the gear type transmission is further transmitted to the rear wheels at the rear of the vehicle body and the front wheels at the front of the vehicle body via the front wheel drive transmission shaft to travel.

[0003] Also, there is known a technique for transmitting a drive path of a front wheel through a continuously variable transmission composed of a hydraulic pump and a hydraulic motor, as in a work vehicle disclosed in Japanese Patent Application Laid-Open No. H8-2279. ing. However, when the gear type transmission and the hydraulic type transmission are mounted together, the transmission case becomes large and the piping connecting these hydraulic devices becomes long. Further, it is required to reduce the number of parts and to reduce the production cost.

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a front wheel speed increasing device for a working vehicle as follows. That is, the rotational power output from the engine 1 is transmitted to the rear of the vehicle body in order to the main clutch 2 and the gear type transmission 3, and the rotational power output from the gear type transmission 3 is further transmitted to the rear wheel differential device 4R at the rear of the vehicle body, and Front wheel drive transmission shaft 5
In a working vehicle that travels by driving the front and rear wheels 15F and 15R by inputting the same to a front wheel differential device 4F in front of the vehicle body through
A hydraulic pump 6 driven by the rotation of the output shaft of the engine 1 is provided at or near the engine 1, and a front axle case 7 that supports the front wheel 15 </ b> F in a freely rotatable manner receives pressure oil from the hydraulic pump 6. A hydraulic motor 8 is provided which rotates the front wheels 15F by combining or switching the rotational power output from the hydraulic motor 8 with the rotational power of the front wheel drive transmission shaft 5.

The rotary shaft of the output shaft 28 of the hydraulic motor 8 is meshed with a ring gear 9 of a front wheel differential device 4F connected to the front wheel drive transmission shaft 5.

[0006]

The working vehicle constructed as described above has a structure in which the front wheels are driven by the gear type transmission 3 and the hydraulic transmission 12, particularly when the hydraulic pump 6 of the hydraulic transmission 12 is used. Since the hydraulic motors 8 are centrally arranged on the entire vehicle body, the connection configuration of the pipes can be made as short as possible and a compact configuration can be achieved as compared with the case where one of them is provided in the transmission case.

Further, if the front wheel drive shaft 5 and the output shaft 28 of the hydraulic motor 8 are configured to share the input of the ring gear 9 of the front wheel differential device 4F, the input gears are provided in comparison with the case where each is provided with an input gear. The number of parts can be reduced.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to a front wheel drive device of an agricultural tractor (hereinafter, tractor 10) as a work vehicle. The tractor 10 includes an engine 1 provided in a bonnet 11 at a front portion of a vehicle body, a clutch housing 14 having a wet main clutch 2 provided at a rear portion of the engine 1, a main transmission 3A and an auxiliary transmission 3B.
And a transmission case 16 in which the gear type transmission 3 is internally connected.

Referring to FIGS. 1 and 2, the periphery of the engine 1 will be described. The engine 1 is constructed such that its left and right sides are formed between the left and right frames of an engine frame 17 formed in a "gate" shape when viewed from above. And an oil pan 18 is positioned below the frame 17. A front bracket 20 and a rear bracket 21 are provided between the left and right frames of the engine frame 17 and in front of the mounting position of the engine 12, for mounting a later-described front axle case 7 so as to be swingable around a longitudinal axis. ing.

A front wheel 15F is provided at the left and right end portions of the front axle case 7 so as to be steerable, and the steering amount is detected by a front wheel angle sensor 19. A weight hanger 22 is connected to a front end of the engine frame 17 so that a weight can be mounted. The continuously variable transmission 12 includes a hydraulic pump 6 that transmits and drives the rotational power of the engine 1, a hydraulic motor 8 that rotates by receiving the pressure oil of the hydraulic pump 2, and pipes and valves that connect these. It consists of hydraulic equipment.

The hydraulic pump 6 is a variable hydraulic pump capable of changing the angle of an internal swash plate and changing the discharge amount by the rotation of an electric motor 24. The hydraulic pump 6 has a mounting block 23 projecting outward from the engine 1. Provided, this mounting block 2
An output shaft is provided from 3 toward the rear, and this output shaft is input into the pump. The hydraulic motor 8 is
An output shaft 28 of the motor 8 is rotatably inserted into an upper portion of the front axle case 7 between the left and right sides of the engine frame 17, that is, at a position where the front wheel differential device 7 </ b> F of the case 7 is located. And the ring gear 9 of the front wheel differential device 7F are always meshed. The hydraulic pump 6 and the hydraulic motor 8 are connected by a rubber pipe 29.

The pipe 29 includes a pipe 19a for sending oil from the clutch housing 14 to the hydraulic pump 6, a pipe 29b for sending oil from the pump 6 to a valve case 41 containing a filter and a pressure reducing valve, and a hydraulic motor from the valve case 41. 8 and a pipe 29d for returning oil from the hydraulic motor 8 to the upper part of the clutch housing 14.

Thus, by rotating the electric motor 24, the amount of oil discharged is changed, and further, the rotation speed of the hydraulic motor 8 is changed to change the rotation speed of the front wheel 15F, that is, the front wheel 15F.
Can be changed. Next, the vicinity of the cockpit 30 of the tractor 10 will be described. The hood 11
A meter panel 31 is provided at the rear of the vehicle, and a steering handle 32 is provided to protrude behind the meter panel 31. A shift lever 33 for switching between the transmissions 3A and 3B and a position lever 34 for lifting and lowering the work implement are protrudingly provided on the side of the cockpit 30. The rotation bases of these levers 33 and 34 are respectively provided at the bases thereof. Potentiometers 33a and 34a for detecting a lever operation angle are provided. Further, various setting devices such as a turning control switch 36 and a front wheel speed increasing amount adjusting dial 37 which will be described later are provided near these lever guides, and these setting signals are transmitted to a controller 38 which is a control unit below the cockpit 30. Configuration.

A rear accelerator case 40 for supporting the rear wheel 15R is provided on both the left and right sides of the transmission case 16, and a hydraulic cylinder 41 for lifting and lowering the work equipment is provided on the rear upper portion of the case 40.
Is provided in the cylinder case 42. The lift arms 43 provided on the left and right sides of the case 42 are vertically rotated by extending and retracting the piston of the cylinder 41. The lift arm 43 has a potentiometer 4 for detecting the arm operation angle.
4 are provided. Thereby, the controller 38 detects the operation angle of the position lever 34, and adjusts the detected angle so that the set angle of the lift arm 43 matches.
The piston of the hydraulic cylinder 41 is configured to expand and contract.

Next, the power transmission configuration of the tractor 10 will be described with reference to FIG. The rotational power of the engine 1 is
The forward / reverse switching device 45, the main transmission 3A, and the sub transmission 3
B is transmitted. And the auxiliary transmission 3
The rotation power output from B is transmitted to the rear rear wheel differential device 4R as it is, and transmitted to the rear wheel 15R via the transmission shaft 47 in the rear axle case 40 and the like. Further, the power output from the auxiliary transmission 3B is returned to the front of the vehicle body via the front wheel drive transmission shaft 5 arranged in the front-rear direction below the transmission case 16, and is input to the front axle case 7. Has become.

Further, a one-way clutch 48 is provided on the front wheel drive transmission shaft 5, and even if the rotation of the hydraulic motor 8 exceeds the rotation transmitted from the auxiliary transmission 3B, the rear wheel 15R It is designed not to be transmitted to Reference numerals 49 in FIG. 4 denote brake discs, and 58 denotes a clutch for turning on and off the rotation of a PTO shaft 57 protruding to the rear of the vehicle body.

The front wheel drive device of the tractor 10 configured as described above includes the gear type transmission 3 and the hydraulic transmission 1
Also when the two are mounted together, the hydraulic pump 6 and the hydraulic motor 8 are centrally arranged at the front of the vehicle body, so that each device is connected as compared with providing one of them at the front end of the transmission case or the like. The piping can be made as short as possible.

Also, since the rotation of the front wheel drive shaft 5 and the output shaft of the hydraulic motor 8 are input by sharing the ring gear 9 of the front wheel differential device 4F, it is compared with providing each with an input gear. Thus, the number of parts can be reduced. Further, even when the continuously variable transmission 12 is attached to a vehicle having only the conventional gear type transmission 3, the same device can be used only by changing a part of the front axle case 7, that is, a central portion where the differential 4F is attached. Since it can be attached, the improvement cost can be minimized.

As another form of the above-mentioned hydraulic front wheel drive device, as shown by reference numeral 8 'in FIG. 4, the mounting position of the hydraulic motor 8 is set to the input portion of the front wheel drive transmission 5 of the front axle case 7. A power take-off gear may be provided on the coaxial shaft 5 so that the gear is always meshed with the pinion gear of the output shaft 28 of the hydraulic motor 8. Further, the hydraulic pump 6 may be provided at the rear of the engine, or may be attached to the engine frame 17 via a bracket or the like.

Next, turning control using the hydraulic transmission 12 will be described. As shown in FIG. 5, the controller 38 of the tractor 10 has a CPU for processing various signals, a RAM for temporarily storing these signals, a ROM for storing a control program, and the like.
The input section includes a potentiometer 34a of the position lever 34, a potentiometer 44 of the lift arm 43, the turning control switch 36, a front wheel speed-up adjustment dial 37, a front wheel turning angle sensor 19, a potentiometer 33a of the shift lever 33, and a potentiometer 33a to be described later. Left and right fender 60
The upper work machine operation switches 61 and 62 are connected and provided.

The output unit includes the electric motor 24,
Solenoids 51 and 52 of switching control valves for lifting and lowering the work machine, and solenoids 64 and 65 of switching control valves for rolling of the work machine
Are connected to each other. Then, the turning control is executed as shown in the flowchart of FIG. First tractor 1
When the electric system 0 is turned on, the controller 38 determines whether or not the turning control switch is ON, and changes the shift position from the operation position of the shift lever 33 to the work area (for example, 10 k
m / h or less). Then, as shown in FIG. 7, a transition line of the motor rotational position set according to the shift position is selected, and a constant α is added to this line by the adjuster 37 and stored in the RAM.

Next, it is determined whether the lift arm angle is equal to or greater than a predetermined value and the front wheel turning angle is equal to or greater than an angle assumed to be turned. If all these are YES, the electric motor 24 is rotated based on the line. . As a result, the peripheral speed of the front wheel 15F is higher than the peripheral speed of the rear wheel 15R, so that a small turning is possible. In addition, the front wheel speed-up pattern is changed according to the shift position.
With the configuration in which the 5F and the rear wheel 15R are driven independently, a smooth small turning can be performed as compared with the case where the 5F and the rear wheel 15R are constantly driven. Further, since the speed increase pattern is manually adjusted, the speed of the front wheel 15F can be increased according to work conditions, for example, the softness of the ground surface or the state of the turf, thereby improving work efficiency.

The graph shown in FIG. 8 shows another form in which the front wheel speed-up pattern is changed according to the shift position.
The configuration is such that the degree of front wheel speed increase is increased as 5F is sharply cut. Next, the lifting device of the tractor 10 will be described. Conventionally, the tractor 10 is provided outside the vehicle, especially the fender
A working machine height changing switch for extending and retracting the piston of the hydraulic cylinder 41, and a rolling cylinder 6 of the working machine.
The configuration is such that a horizontal posture change switch of a working machine for extending and retracting the piston 6 is provided. However, since these switches are concentrated on one side of the vehicle body, and the height change switch and the posture change switch are arranged separately on the left and right, respectively, especially for large tractors, work machines with wide left and right width When the state of the work machine is changed, it is necessary to move the switch to the side where the switch is provided and operate the switch.

Therefore, here, two switches (first switch 6) are provided at the rear ends of the left and right fenders 60, respectively.
1, the second switch 62), and both switches 61, 62
The operation target is switched between the hydraulic cylinder 41 for lifting and lowering the work equipment or the hydraulic cylinder 66 for rolling the work equipment by the mode switching operation set in advance, and the change of the height of the work equipment and the change of the left and right posture of the work equipment are performed on both sides. It was configured to be able to be operated from.

Referring to the control flowchart shown in FIG. 10, when the electric system is turned on together with the engine 1, the controller 38 reads the connection states of various switches. First, the operation mode of the left and right first and second switches 61 and 62 is set to the "working machine elevating mode", and the switch operation, that is, the input signal is detected. When the first switch 61 is ON, power is supplied to the ascending solenoid 51 of the switching control valve that sends hydraulic oil to the hydraulic cylinder 41 for elevating and lowering the working machine. Also, when the second switch is ON, the lowering solenoid 52 of the switching control valve that sends the pressure oil to the hydraulic cylinder 41 is energized.

Next, whether or not there has been a mode switching operation using the switches 61 and 62, that is, whether or not the first switch 61 and the second switch 62 of the left and right fenders 60 have been simultaneously turned on for a certain period of time. And if this is YES, the "working machine elevating mode"
To the "working machine rolling mode" to detect each switch operation, that is, an input signal. At this time, when the first switch 61 is ON, the solenoid 64 of the switching control valve for extending the piston of the hydraulic cylinder 66 for rolling the working machine is energized. When the second switch is ON, power is supplied to the solenoid 65 of the switching control valve for shortening the piston of the rolling hydraulic cylinder 66. As described above, the operation of both switches 65 and 66 is periodically detected. The mode is switched each time both of the switches detect a pressing operation continuously for a certain period of time.

The tractor 10 constructed as described above has two switches 6 on each of the fenders 60 on both sides of the vehicle body.
5 and 66 are provided, and the operation target is switched between the hydraulic cylinder 41 for lifting and lowering the working machine or the cylinder 66 for rolling by simultaneous pushing operation using the switches 65 and 66. As a result, the number of parts of the switch can be reduced, and the work machine can be lifted and lowered and the right and left attitude can be changed from one side of the vehicle even when the work machine is to be attached / detached or mud is removed. Can be achieved.

[Brief description of the drawings]

FIG. 1 is a side view of a front axle case partially sectioned.

FIG. 2 is a side view around an engine.

FIG. 3 is an overall side view of the tractor.

FIG. 4 is a power transmission diagram of a tractor.

FIG. 5 is a block diagram showing a connection state of a controller.

FIG. 6 is a control flowchart of turning control.

FIG. 7 is a graph showing the left and right turning angles of a front wheel and the rotational position of a motor.

FIG. 8 is another form of FIG. 7;

FIG. 9 is a rear view of the tractor.

FIG. 10 is a flowchart showing the mode switching of a work implement lifting / lowering operation switch outside the vehicle.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 2 Main clutch 3A Main transmission 3B Sub transmission 4F Front wheel differential 4R Rear wheel differential 5 Front wheel drive transmission shaft 6 Hydraulic pump 7 Front axle case 8 Hydraulic motor 9 Ring gear 10 Tractor

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Naohiko Ishii 1-Yakura, Tobe-cho, Toyo-cho, Iyo-gun, Ehime Prefecture Iseki Agricultural Machinery Co., Ltd. Engineering Department

Claims (2)

[Claims] 1. A rotary power output from an engine 1 is transmitted to a main clutch 2 and a gear type transmission 3 in order to the rear of the vehicle body, and the rotary power output from the gear type transmission 3 is further transmitted to a rear wheel differential device at the rear of the vehicle body. 4R and a front wheel differential 4F on the front of the vehicle via the front wheel drive transmission shaft 5
5F and 15R, a hydraulic pump 6 driven by rotation of an output shaft of the engine 1 is provided at or near the engine 1,
The front axle case 7 that supports the 5F in a freely rotatable manner is provided with a hydraulic motor 8 that rotates by receiving pressure oil from the hydraulic pump 6. The rotational power output from the hydraulic motor 8 is used to rotate the front wheel drive transmission shaft 5. A front wheel drive device for a work vehicle, wherein the front wheel 15F is configured to drive the front wheels 15F by merging or switching with motive power. 2. A front wheel differential device 4F for connecting a rotation shaft of an output shaft 28 of the hydraulic motor 8 to the front wheel drive transmission shaft 5.
The front wheel drive device for a working vehicle according to claim 1, wherein the front wheel drive device is configured to mesh with the ring gear (9).