JP3713375B2 - Shift steering device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a shift steering device for a vehicle provided with a pair of crawler traveling means on the left and right, such as a combine and a bulltozer.
[0002]
[Prior art]
Conventionally, as shown in FIG. 3, this type of shift steering device transmits the power of the engine 1 and the like to the shaft 5, the bevel gears 6a and 6b, and the planetary gear mechanisms 8A and 8B via the transmission 2 as straight power. At the same time, the hydraulic pressure from the variable displacement hydraulic pump 3 driven by the engine 1 is supplied to the hydraulic motor 15 via the operation valve 14, and the rotational power from the hydraulic motor 15 and the straight power from the transmission 2 are converted into planetary gears. There is a mechanism in which the mechanisms 8A and 8B are combined as a differential mechanism, and a rotational speed difference is given to the left and right output shafts 13a and 13b so as to turn.
[0003]
[Problems to be solved by the invention]
By the way, in the above-mentioned conventional example, the rotational power from one hydraulic motor and the straight traveling power from the transmission are combined as a differential mechanism with a planetary gear, and a rotational speed difference is given to the left and right output shafts to make a turning operation. However, in order to give a difference in rotational speed between the left and right output shafts and to make a turning operation, the left and right planetary gear mechanisms are connected to the left and right planetary gear mechanisms via gears by one hydraulic motor driven by the hydraulic pressure from the operation valve. At the same time, since the rotation is applied in the forward and reverse directions, when the turning operation is performed due to the difference in rotational speed, only the rotation of one hydraulic motor is changed and the other is not changed. There is a problem that it is not possible to freely turn the hydraulic motor by rotating it in the opposite direction.
Also, depending on the turning direction, the load on the left and right output shafts varies greatly, and when turning, the rotational power is applied only to the hydraulic motor on the output shaft side where the load is large, to cope with load fluctuations. There is also a problem that it cannot be done.
[0004]
Therefore, according to the present invention, a hydraulic drive mechanism including a hydraulic pump, a hydraulic motor, a valve, and the like is individually provided for the left and right output shafts in order to give a rotational speed difference to the left and right output shafts to perform turning. Install and rotate the left and right output shafts separately, give a speed difference, make large turning maneuvers and cope with load fluctuations on the output shaft to improve steering and stability With the goal.
[0005]
[Means for Solving the Problems]
The present invention is configured to transmit power from a straight traveling mechanical drive means including a transmission for transmitting engine output to an output shaft via left and right planetary gear mechanisms, and a hydraulic pump driven by the engine; Power from a hydraulic drive means comprising a hydraulic motor and a valve is transmitted to the planetary gear mechanism so as to impart rotation, and the outputs of the straight running mechanical drive means and the turning hydraulic drive means are synthesized. In the shift steering device configured to be able to adjust the drive speed and drive direction of the left and right output shafts, the hydraulic drive means for imparting rotation to the planetary gear mechanism includes a variable displacement hydraulic pump and a variable displacement hydraulic pump. A variable capacity device comprising a regulator valve and an actuator for controlling the discharge amount of pressure, a pressure compensated control valve connected to a variable capacity hydraulic pump, and a pressure Constituted by a hydraulic motor that is connected to償型control valve, provided in each hydraulic driving means for the left and right planetary gear mechanism connects the left and right pressure compensated control valve in the hydraulic drive means in the actuator, The actuator is connected to an operating device consisting of a gerotor that supplies a flow rate corresponding to the rotational angle of the handle mechanically interlocked with the rotary valve, and the pressure compensation type control valve is operated by the operating pressure from the operating device to form a hydraulic motor. Supply hydraulic pressure and introduce the higher of the load pressure on the left and right hydraulic motor side into the regulator valve of the variable capacity device via the shuttle valve, and discharge the hydraulic pump according to the load on the left and right output shafts To control.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. The same components as those in the conventional example will be described with the same names and symbols.
[0008]
In the shift steering apparatus according to this embodiment, as shown in FIG. 1, reference numeral 1 denotes a prime mover such as an engine, and a transmission 2 having drive gears 2 a and 2 b on the output shaft of the prime mover 1. Is provided and constitutes the mechanical drive means M.
[0009]
A variable displacement hydraulic pump (hereinafter referred to as a hydraulic pump) 3 is connected to the drive gear 2a, and a clutch 4 is connected to the drive gear 2b.
[0010]
A shaft 5 that directly transmits the rotational power from the engine 1 is connected to one end of the clutch 4, and a bevel gear 6 a is attached to the shaft 5 and meshes with the bevel gear 6 b.
[0011]
The bevel gear 6b is coupled to the sun shaft 7, and the sun shaft 7 is joined to the respective bracelets 9a and 9b of the first and second planetary gear mechanisms 8A and 8B.
[0012]
Planet gears 10a and 10b are rotatably supported on the bracelets 9a and 9b, respectively.
[0013]
The planetary gears 10a and 10b are engaged with the sun gears 11a and 11b and the ring gears 12a and 12b, which are coaxially fitted to the sun shaft 7, and rotate.
[0014]
Output shafts 13a and 13b are coupled to the ring gears 12a and 12b, and the output shafts 13a and 13b are engaged with a crawler (not shown) so that the rotational power from the engine 1 is directly transmitted.
[0015]
The hydraulic pump 3 includes a capacity variable device 21 that controls the discharge amount of the hydraulic pump 3 on the suction side and the first and second pressure compensation control valves (hereinafter referred to as first and second control valves). 14a, 14b).
[0016]
The variable capacity device 21 includes a cylinder 21A that is an actuator that tilts a swash plate, a slant shaft, and the like (not shown) of the hydraulic pump 3, and a regulator valve 21B that controls the cylinder 21A.
[0017]
The cylinder 21A has oil chambers 21b and 21c defined by the piston 21a, and pressure oil is inserted into the oil chamber 21b from the main pipeline 20a.
[0018]
The regulator valve 21B is a control valve of 3 ports (a, b, c) and 2 positions (A, B). The port a is in the oil chamber 21c of the cylinder 21A, the port b is in the tank T, and the port c is in the pump 3 Are respectively connected to the discharge side main pipeline 20a.
[0019]
The first and second control valves 14a and 14b are manually operated 5 ports (a, b, c, d, e) 3 positions (A, B, C) with a variable throttle 14c, and pressure compensation of the closed center. This is a type control valve.
[0020]
The upstream port a of the first and second control valves 14 a and 14 b is connected to the discharge side main pipe 20 a of the pump 3, and the port b is connected to the tank T.
[0021]
The downstream ports c and e of the first and second control valves 14a and 14b are connected to the first and second hydraulic motors 15a and 15b, and the hydraulic pump 3, the first and second control valves 14a and 14b, The first and second hydraulic motors 15a and 15b constitute a hydraulic drive means P.
[0022]
A pilot line 23c is connected to the regulator valve 21B from the port d of the first and second control valves 14a and 14b via the pilot lines 23a and 23b and the shuttle valve 22.
[0023]
Further, the first and second control valves 14a and 14b in the hydraulic drive means P are connected by a double rod cylinder (hereinafter referred to as a cylinder) 24 as an actuator, and are interlocked by the operation of the cylinder 24. .
The cylinder 24 defines oil chambers 24b and 24c by a piston 24a. The oil chambers 24b and 24c are mechanically interlocked with a rotary valve 25a and a rotary valve 25a operated by a handle (not shown). It is connected to an operating device 25 such as a gerotor 25b that supplies a flow rate corresponding to the rotation direction and rotation angle by pipes 25c and 25d, and pressure oil is supplied from a hydraulic pump 26.
Therefore, when a handle (not shown) is operated, pressure oil is supplied from the operating device 25 to the oil chamber 24b or 24c of the cylinder 24 in accordance with the rotation direction and rotation angle of the handle, and the first operation is performed by the operation of the piston 24a of the cylinder 24. , 2 control valves 14a, 14b are switched in the opposite direction.
On the other hand, the transmission gears 17a and 17b are coupled to the shafts 16a and 16b of the first and second hydraulic motors 15a and 15b, and brakes 18a and 18b are provided.
[0024]
The transmission gears 17a and 17b are further engaged with the sun gears 11a and 11b via the gears 19a and 19b, and the sun gears 11a and 11b are also engaged with the planetary gears 10a and 10b.
[0025]
The brakes 18a and 18b brake the rotation of the hydraulic motors 15a and 15b by an actuator (not shown).
[0026]
Next, the operation will be described.
Now, when a vehicle (not shown) is in a stopped state, the clutch 4 is disengaged, the rotational power from the engine 1 is not transmitted to the output shafts 13a and 13b, and the shafts 16a and 16b of the hydraulic motors 15a and 15b are not transmitted. The hydraulic motors 15a and 15b are prevented from rotating by brakes 18a and 18b provided on 16b.
[0027]
First and second control valves 14a, when 14b is in position C, the pilot lines 23a, 23b are connected to the tank T Runode, the pilot pressure is not generated. Therefore, the regulator valve 21B is switched to the position A, and the discharge pressure of the hydraulic pump 3 is introduced into the oil chambers 21b and 21c of the cylinder 21A . When the discharge pressure is introduced into the oil chambers 21b and 21c in this way, the piston 21a of the cylinder 21A is operated to tilt the variable portion 3a of the hydraulic pump 3, thereby minimizing the discharge amount of the pump 3 and the hydraulic pressure. The motors 15a and 15b are also connected to the tank T and are stopped without hydraulic pressure.
[0028]
Next, when the vehicle travels straight, when the clutch 4 that has been disconnected in the stopped state is gradually connected, the rotational power from the engine 1 is converted to the shaft 5, the bevel gears 6a and 6b, the sun shaft 7, and the planetary gear. The power can be transmitted to the mechanisms 8A and 8B and the output shafts 13a and 13b to drive a crawler (not shown) so that the vehicle can travel straight.
[0029]
If the vehicles turning steered by operating the steering wheel (not shown), the gerotor 25b is operated to drive the cylinder 24 to either. Thus, when the cylinder 24 moves to either one, the first and second control valves 14a and 14b are switched in opposite directions. When the first control valve 14a is switched in the opposite direction and the brakes 18a and 18b are released, the pressure oil from the hydraulic pump 3 is supplied to the hydraulic motors 15a and 15b, and the motors 15a and 15b are opposite to each other. Rotate. Thus, if both hydraulic motors 15a and 15b rotate reversely, the vehicle will turn .
[0038]
【The invention's effect】
According to the present invention, the operation amount for operating the pressure compensation type control valve can be shifted to the left and right with the handle provided on the rotary valve of the operating device as if it were a handle operation .
[Brief description of the drawings]
1 is a hydraulic circuit diagram of a transmission steering apparatus according to the embodiment of the present onset Ming embodiment.
FIG. 2 is a hydraulic circuit diagram of a shift steering device showing a conventional example .
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Engine 2 Transmission 2a, 2b Gear 3 Hydraulic pump 4 Clutch 5 Shaft 6a, 6b Bevel gear 7 Sun shaft 8A, 8B Planetary gear mechanism 9a, 9b Arm ring 10a, 10b Planetary gear 11a, 11b Sun gear 12a, 12b Ring gear 13a, 13b Output shafts 14a, 14b Control valves 15a, 15b Hydraulic motors 16a, 16b Shafts 17a, 17b Transmission gears 18a, 18b Brakes 19a, 19b Gears 20a Main line 21 Flow variable device 21A Cylinder 21a Piston 21b, 21c Oil chamber 21B Regulator valve 22 Shuttle valves 23a, 23b, 23c pilot line 24 the cylinder 24a a piston 24b, 24c oil chamber 25 operating device 25a the rotary valve 25b gerotor 25c, 25d line 26 hydraulic pump M mechanical drive means P Pressure driving means T tank

Claims (1)

A hydraulic pump and a hydraulic motor driven by the engine, and configured to transmit power from a straight traveling mechanical drive means including a transmission for transmitting the output of the engine to the output shaft via the left and right planetary gear mechanisms; Power from a hydraulic drive means comprising a valve is transmitted to the planetary gear mechanism so as to impart rotation, and the outputs of the straight drive mechanical drive means and the turning hydraulic drive means are combined, in adjustably shifting steering system which constitutes the driving speed and the driving direction of the output shaft, a variable displacement hydraulic pump with a hydraulic drive means for imparting rotation to the planetary gear Organization, the discharge amount of the variable displacement hydraulic pump Variable capacity device comprising a regulator valve and an actuator for controlling the pressure, a pressure compensation control valve connected to the variable displacement hydraulic pump, and a pressure compensation control valve Constituted by a hydraulic motor that is connected, provided individually hydraulic drive means for the left and right planetary gear mechanisms, and left and right pressure compensated control valve in the hydraulic drive means connected with the actuator, the rotary valve actuator Connect an operating device consisting of a gerotor that supplies a flow rate corresponding to the rotational angle of the mechanically interlocking handle, and operate the pressure compensation type control valve with the operating pressure from the operating device to supply hydraulic pressure to the hydraulic motor, The higher of the load pressure on the left and right hydraulic motors is introduced into the regulator valve of the variable displacement device via the shuttle valve, and the discharge volume of the variable displacement hydraulic pump is controlled according to the load on the left and right output shafts. A shift steering device characterized by that.

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