JPS6317701Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field The present invention is designed to run along a tobacco cultivation ridge or a tea cultivation ridge while straddling the ridge.
This invention relates to a traveling device for an elevated management work vehicle that performs various agricultural tasks such as sowing, planting, and harvesting.

Prior Art Conventionally, as shown in Japanese Unexamined Patent Publication No. 57-44533, four hydraulic motors were provided to drive the front, rear, left, and right wheels, and each hydraulic motor for the left front and rear wheels was driven by a left hydraulic pump. , a technology was developed in which each hydraulic motor for the front and rear wheels on the right side was driven by a hydraulic pump for the right side.

Problems to be Solved by the Invention In the prior art, the front and rear wheels on the left side and the front and rear wheels on the right side are driven by independent closed-loop left and right hydraulic circuits using four hydraulic motors and two hydraulic pumps. , a switching valve for 2WD/4WD switching that connects the front and rear hydraulic motors in parallel communication or disconnection, and connects the left and right hydraulic motors on the normally driven side in communication between the suction sides or in communication or disconnection between the suction side and the discharge side. By installing a manual switching valve, 4WD driving,
It is possible to switch between 2WD driving, freewheel operation, deflock operation, and differential operation, but it is difficult to maintain the discharge volume of the left and right hydraulic pumps completely the same, and the left and right rotation during deflock operation is difficult. This tends to cause a difference, causing the front and rear wheels on the side with a lower displacement to move as if being pulled by the wheels on the opposite side, which causes problems such as acting as a braking force on the front and rear wheel hydraulic systems on the side with a higher displacement. ,
Due to the difference in the discharge amount of the hydraulic pumps between the left and right sides, hydraulic oil is likely to be discharged from either the left or right hydraulic pump even when the vehicle is in neutral, resulting in problems such as a reliable neutral stop cannot be easily achieved.

Furthermore, since there is no gear changeover valve for connecting the hydraulic motors of the left and right rear wheels in series or separately, and there is no locking member to limit the operating timing of the gear changeover valves, it is easy to connect the left and right rear wheels. In addition to not being able to perform speed-up driving, it is also not possible to easily set the timing at which speed-up operation is possible for the left and right rear wheels, and there are problems in that it is not possible to easily improve the running drive function and handling operability.

Means for Solving the Problems However, in the present invention, the left side hydraulic motor and the left wheel hydraulic pump, which drive the left front and rear wheels separately, are connected in a closed loop circuit, and the right side front and rear wheels are separately driven. The hydraulic motor for the right side to be driven and the hydraulic pump for the right wheel are connected in a closed loop, and the hydraulic motors for the left and right front wheels are connected or disconnected to the hydraulic pumps for the left and right wheels. In a device equipped with a hydraulic switching valve for 2WD/4WD switching, each suction side and each discharge side of each hydraulic motor for the left and right rear wheels are constantly connected to each other by a bypass circuit provided with a throttle valve, and
A gear changeover valve is provided to connect the suction side and discharge side of each hydraulic motor for the left and right rear wheels in series or separately, and there is also a manual changeover valve that drives the left and right rear wheels in a differential state. The present invention is characterized in that a lock member is provided to prevent series connection switching of the speed change change valves except during dynamic changeover.

Function: Therefore, when driving the front and rear wheels on the left and right sides in a defrocked state, even if there is a difference in the discharge volume of the left and right hydraulic pumps, the discharge volume on the left and right sides is adjusted by a bypass circuit equipped with a throttle valve. can eliminate the difference between
It is possible to prevent brake operation during deflock due to the difference in discharge amount, and even if there is a difference in the discharge amount between the left and right hydraulic pumps, it is possible to easily achieve a reliable neutral stop. The hydraulic motors for the left and right rear wheels can be connected in series only when the wheels are being driven in a differential state, making it easy to simplify speed change operations and improve safety.

Embodiment Hereinafter, an embodiment of the present invention will be described in detail based on the drawings. Figure 1 is an overall side view of the elevated management work vehicle.
FIG. 2 is a plan view of the same, in which 1 and 2 are front and rear body frames, 3 is a torso body frame whose rear end side is fixed to the rear body frame 2, and 4 is the front end of the torso body frame 3. 5a and 5b are front axle cases that are slidably attached to and detached from each end of the front body frame 1 via positioning pins 6, 6;
7, 7 are front axle frames supported horizontally by axle cases 5a, 5b, 8a, 8b;
9a and 9b are hydraulic motors for driving the front wheels that are integrated into the front axle cases 5a and 5b, and 10a and 10b are the rear vehicle body. Left and right rear axle cases 12 are slidably attached to both ends of the frame 2 via positioning pins 11, 11;
a, 12b are running rear wheels that are mounted below the rear axle cases 10a, 10b via rear axle frames 13, 13, and 14a, 14b are hydraulic pressures for driving the rear wheels that are integrally assembled in the rear axle cases 10a, 10b. A motor 15 is an engine section in which an engine 16 is mounted approximately in the center between the front and rear wheels 8a and 12a on the left side of the body body frame 3, and a driving frame 17 is installed approximately in the center between the front and rear wheels 8b and 12b on the right side of the body body frame 3. 18 is fixed, and a driving operation unit is equipped with a driver's seat 19, a steering handle 20, etc.;
21 is a battery storage chamber installed below the driver's seat 19; 22 is a safety frame that protects the driving operation section 17; and 23 is a frame mounted at the center of the front part of the body frame 3 to connect the input shaft to the engine 17. The PTO transmission cases 24 and 25 to be driven and connected are the left and right row hydraulic motors 9a, 14a, 9b, 14b which are interlocked and connected to the transmission case 23.
Two variable displacement hydraulic pumps for the left wheel and the right wheel are used for operation, 26 is the hydraulic pump 2.
4, a charge pump provided adjacent to 25, 2
7 is the PTO output shaft 2 of the transmission case 23
8 is a PTO rear transmission housing which is detachably and directionally connected; 29 is the hydraulic pump 24, 2;
a gear shift lever connected to 5 to perform a travel gear shift operation, 3;
0 is connected to the transmission case 23.
31 is a hydraulic elevator having a lift arm 32 provided approximately at the center of the rear body frame 2; 33 is a lever for lifting and lowering the work equipment for operating the hydraulic elevator; 34 is a lever connected to the machine via a lower link 35 and a top link 36 This is a rotary tillage machine equipped with a rotary 37 that is pulled backwards, and is configured to run the machine across tobacco cultivation ridges, tea cultivation ridges, etc., and perform tillage work using the working machine 34.

FIG. 3 is a hydraulic circuit diagram, in which running wheels 8a, 1 are installed on the variable displacement hydraulic pump 24 in the left row of the machine.
One 2-position manual hydraulic pressure switching valve 38 for 2WD/4WD switching connects the hydraulic motors 9a, 14a of 2a to a parallel circuit, and appropriately cuts off the hydraulic pressure supply to the hydraulic motor 9a between these hydraulic motors 9a, 14a. are intervening. Also, the other variable displacement hydraulic pump 25
The hydraulic motors 9b and 14b of the running wheels 8b and 12b arranged on the right row of the aircraft are connected to a parallel circuit, and the hydraulic pressure supply to the hydraulic motor 9b is appropriately cut off between these hydraulic motors 9b and 14b. The other two-position manual hydraulic switching valve 39 for switching is provided.

Furthermore, the hydraulic motor 14a and the hydraulic pump 2
4 and between the hydraulic motor 14b and the hydraulic pump 25 circuit, left and right front and rear wheels 8a, 12a, 8b,
A 3-position manual hydraulic switching valve 40 is provided for switching the differential drive 12b to a differential, differential suspension, or emergency drive suspension state.

Furthermore, shuttle valves 41 and 42 are provided between the switching valves 38 and 39 and the hydraulic motors 9a and 9b.
These shuttle valves 41, 4
A 2-position manual hydraulic switching valve 44 for freewheeling is interposed between the outlet side of 2 and the hydraulic oil tank 43 in the connection circuit.

On the other hand, by operating the handle 20, the front wheel 8
A steering cylinder 45 for controlling the steering of wheels a and 8b is connected to a hydraulic oil tank 43 via a power steering circuit 46 and a quick coupler 47.
It is connected to. In addition, the hydraulic pumps 24, 2
5 and a power steering circuit 46, and a line filter 48 and a freewheel circuit 49 are provided in the middle of the connection circuit between the charge pump 26 and the power steering circuit 46.

Incidentally, between the hydraulic motors 14a and 14b, there is provided a series speed changeover valve 50 that appropriately communicates the discharge side a or b of one motor 14a or 14b with the suction side c or d of the other motor 14b or 14a. When the switching valve 40 is in the differential state in a 2-drive state in which only 14a and 14b are driven, the hydraulic pressure supply circuit to these two hydraulic motors 14a and 14b is made into a series circuit, and the motor 14
It is configured to increase the rotational output of a and 14b.

In addition, forward and reverse bypass circuits 52a and 52b having throttle valves 51a and 51b are interposed between the independent hydraulic supply circuits of the hydraulic motor 14a and the switching valve 38, and between the hydraulic motor 14b and the switching valve 39, respectively. At the time of suspension (defrotting), hydraulic pressure is supplied to the left and right row motors 9a, 14a and 9b, 14b without creating a flow rate difference, and a rotation difference is created between the front and rear wheels 8a, 12a, 8b, 12b of the left row and right row. The structure is such that synchronous rotational drive is possible without causing any

As shown in FIGS. 4 and 5, the handle 2
Operation column 5 of the operation section 17 equipped with 0
3, a cylinder block 54 containing the switching valve 40 and a cylinder block 55 containing the speed change switching valve 50 are installed inside, and each switching valve 4
A driving mode switching lever 56 for switching between 0 and 50 and a speed change operation lever 57 are made to protrude outside the operation column 53. A regulating arm 58, which is a locking member, is fixed to the speed change operating lever 56, and when the traveling mode switching lever 56 is in the emergency drive interruption (emergency) or differential suspension (defrot) position, the tip of the arm 58 is switched to this position. The shift operation lever 57 is brought into contact with the lever 56 to prevent the shift operation lever 57 from moving to the high speed position, and only when the changeover lever 56 is in the differential position.
is configured to shift to a high speed position.

As described above, the left hydraulic motors 9a, 14a that drive the left front and rear wheels 8a, 12a separately and the left wheel hydraulic pump 24 are connected in a closed loop, and the right front and rear wheels 8b, 12b are connected to each other in a closed loop. The hydraulic motors 9b, 14b for the right side and the hydraulic pump 25 for the right wheel, which are driven separately, are connected in a closed loop circuit, and the hydraulic motors 9a, 9b for the left and right front wheels 8a, 8b are connected to the hydraulic motors 9a, 9b for the left and right wheels. In a device equipped with hydraulic switching valves 38 and 39 for 2WD and 4WD switching which are connected to each hydraulic pump 24 and 25 in a communication or disconnected state, each suction of each hydraulic motor 14a, 14b for left and right rear wheels 12a, 12b is provided. Bypass circuits 52a, 52b provided with throttle valves 51a, 51b are used to constantly connect the side and each discharge side, respectively, and the suction side and discharge side of each hydraulic motor 14a, 14b for the left and right rear wheels 12a, 12b are connected at all times. A transmission switching valve 50 is provided to switch between series connection or separate connection state, and the transmission switching valve 50 is set to a differential state except when the manual switching valve 40 which drives the left and right rear wheels 12a, 12b is in a differential state. A regulating arm 58 is provided as a locking member to prevent series connection switching.

Further, a regulating plate 59, which is a locking member, is fixed to the switching lever 56, and when the switching lever 56 is in the differential position and the operating lever 57 is in the high speed position, the differential operation of the switching lever 56 is interrupted (defrot). and is configured to prevent transition to emergency drive interruption (emergency).

In addition, 60 in FIG. 3 indicates the switching valves 38, 39,
Single 2WD/4 to operate 44 in conjunction
This is a control lever for switching drive.

This embodiment is configured as described above,
Now each switching valve 38, 39, 40, 44, 50 is in the third position.
In the state shown in the figure, the switching valve 40 is in the neutral position and the connection circuit between the left row hydraulic motors 9a, 14a and the right row hydraulic motors 9b, 14b is cut off, which is a so-called differential suspension (defrot) state. In regards to
Hydraulic pressure from the hydraulic oil tank 43 is supplied to the left and right row hydraulic motors 9a,
14a, 9b, and 14b, the pump 24 drives the motors 9a, 14a, and the pump 25 drives the motors 9b, 14b appropriately in the forward and reverse directions.

Then, by operating the lever 56, the switching valve 40
When switched in the direction of the solid line arrow, the left row hydraulic motors 9a, 14a and the right row hydraulic motors 9b, 14b
The hydraulic pressure supply circuits are connected to create a so-called differential state. And now hydraulic pumps 9b, 14b
Alternatively, when an abnormality occurs in this hydraulic drive system, if the switching valve 40 is switched in the direction of the dashed arrow by operating the lever 56, the left row hydraulic motors 9a, 14a
The hydraulic outlets of the right-row hydraulic motors 9b, 14b communicate with each other, and the hydraulic outlets of the hydraulic motors 9b, 14b communicate with the hydraulic inlets of the hydraulic motors 9a, 14a, respectively.
A closed circuit is formed between the motors 9a, 9b, 14a, and 14b, and hydraulic pressure is circulated between the motors 9a, 9b, 14a, and 14b to freely rotate them.

Moreover, these front and rear wheels 8a, 8b, 12a, 12
In the 4WD state of b drive, the operation lever 60
When the switching valves 38, 39, and 40 are switched by operating the hydraulic pumps 24 and 25, the hydraulic motor 9
The supply of hydraulic pressure to the left and right front wheels 8a, 8b is cut off, and the drive of the left and right front wheels 8a, 8b is stopped, and the rear wheels 12a, 9b are stopped.
Only 12b is driven in a two-wheel drive state.

During the traveling operation in such a two-wheel drive state, the lever 56
and 57 to switch the switching valves 40 and 50 to the differential and series positions in the direction of the solid line arrow in the figure, the left and right hydraulic motors 14a, 14b
The hydraulic pressure supply circuit is a series circuit, and all the hydraulic pressures now being sent in the direction of the solid line arrow from the pumps 24 and 25 are supplied to the right hydraulic motor 14b, and the hydraulic pressure discharged from the motor 14b is the left hydraulic pressure. It is supplied to the motor 14a. As a result, the amount of oil pressure supplied to these motors 14a and 14b increases, and the motor 1
4a, 14b rotate at high speed, and the rear wheels 12a, 12
Increase the rotation speed of b.

Furthermore, when operating the lever 57 to switch to such a state, the switching lever 56 must be in the differential (differential) position. When in the emergency drive interruption (emergency) position, the regulating arm 58 disengages the lever 5.
6 and prevents the lever 57 from switching to the high speed position, and enables high speed switching only in the differential state. Also, these 2
When the switching lever 56 is moved to a position other than the differential position in the driving speed state, the regulating plate 59 of the lever 56 comes into contact with the regulating arm 58 of the lever 57 to prevent these malfunctions.

Effects of the Invention As is clear from the above embodiments, the present invention includes left-side hydraulic motors 9a, 14a and a left-wheel hydraulic pump 2 that drive the left front and rear wheels 8a, 12a separately.
Right side hydraulic motors 9b, 14b and right wheel hydraulic pump 25 which drive the right front and rear wheels 8b, 12b separately.
are connected in a closed loop circuit, and the hydraulic motors 9a and 9b for the left and right front wheels 8a and 8b are connected to the hydraulic pumps 24 and 25 for the left and right wheels by switching between communication and disconnection. In a device equipped with four-wheel drive switching hydraulic switching valves 38 and 39, each hydraulic motor 14 for left and right rear wheels 12a and 12b
a, 14b on each suction side and each discharge side with a throttle valve 5.
Bypass circuits 52a and 52 provided with 1a and 51b
b, and each hydraulic motor 14 for the left and right rear wheels 12a, 12b.
A transmission changeover valve 50 is provided to connect the suction side and the discharge side of the wheels 12a and 14b in series or separately.
Since a locking member 58 is provided to prevent the series connection switching of the transmission switching valve 50 except when the manual switching valve 40 that drives the transmission is switched to a differential mode, the left and right front and rear wheels 8a, 12a and 8b, 12b are kept in a deflock state. When driven with
The bypass circuits 52a and 52b provided with the pumps 1b can eliminate the difference in the discharge amount between the left and right sides, and prevent the braking operation during deflock due to the difference in the discharge amount.
Even if there is a difference in the discharge amount, a reliable neutral stop can be easily performed, and the left and right rear wheels 12a can be stopped only when the left and right rear wheels 12a, 12b are driven in a differential state by the regulation of the locking member 58. ,12
The hydraulic motors 14a and 14b of b can be connected in series, which provides practical effects such as simplifying the speed change operation and easily improving safety.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention; Fig. 1 is an overall side view of an elevated management work vehicle, Fig. 2 is a plan view thereof, Fig. 3 is a hydraulic circuit diagram, and Fig. 4 is a main part. FIG. 5 is a side view of the main parts. 8a, 8b...Front wheel, 9a, 9b...Hydraulic motor for front wheel, 12a, 12b...Rear wheel, 1
4a, 14b...Hydraulic motor for rear wheels, 24...
...Hydraulic pump for left wheel, 25...Hydraulic pump for right wheel, 38, 39...Hydraulic switching valve for 2WD/4WD switching, 40...Manual switching valve, 50...Transmission switching valve,
51a, 51b...throttle valve, 52a, 52b...
Bypass circuit, 58...Regulation arm (lock member).

Claims (1)

[Scope of utility model registration request] The left side hydraulic motors 9a, 14a that drive the left front and rear wheels 8a, 12a separately and the left wheel hydraulic pump 24 are connected in a closed loop, and
The right hydraulic motors 9b, 14b for driving the right front and rear wheels 8b, 12b separately and the right wheel hydraulic pump 25 are connected in a closed loop, and each hydraulic motor 9a, for the left and right front wheels 8a, 8b is connected in a closed loop. 9b
Each hydraulic pump 24, 25 for the left wheel and right wheel
In a device equipped with hydraulic switching valves 38 and 39 for 2WD and 4WD switching, which are switched between communication and disconnection, the suction side and the discharge side of the hydraulic motors 14a and 14b for the left and right rear wheels 12a and 12b are connected. , a bypass circuit 52 provided with throttle valves 51a and 51b.
a and 52b, and also connects the suction side and the discharge side of the respective hydraulic motors 14a, 14b for the left and right rear wheels 12a, 12b in series connection or in a separate connection state.
0 is provided, and the left and right rear wheels 12a are in a differential state,
12b. A traveling device for an elevated management work vehicle, characterized in that a lock member 58 is provided to prevent series connection switching of the transmission switching valve 50 except during differential switching of the manual switching valve 40 that drives the transmission switching valve 12b.