JPH07149160A - Direct advance correction control device at starting time for hydraulically driven type catapillar - Google Patents

Abstract

PURPOSE:To prevent travelling of a vehicle to the right or the left just after starting the vehicle against a driver's will who tries to maintain straight advance condition. CONSTITUTION:First and second planetary gears on right and left acting as a variable speed mechanism for low and high speed stages arranged in both final reduction gears, fixed clutches 10-3, 7 and rotary clutches 11, 18 to be combined with the first planetary gear are provided, in a catapillar travelling by final reduction gears 7, 8 having the same structure on the right and the left to be driven by means of right and left, two pairs of oil pressure pumps 3, 4 and hydraulic motors 5, 6. A control device 40 to process a required signal by inputting signal from each detector such as a rotational speed detector for oil pressure pumps 3, 4 hydraulic motors 5, 6 and the like, the detectors for a positioning switch and a handle angle of a speed change lever to output set state signals for a vehicle operating device, and an actuator for the oil pressure pumps and the clutches whose operation is controlled by output from the control device are also provided therein.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to straight-ahead correction at start of a tracked vehicle having two sets of hydraulic pumps and hydraulic motors for driving two sets of left and right final reduction gears, and control of rotational speed of the hydraulic motors.

[0002]

2. Description of the Related Art Conventionally, as one of the drive systems for tracked vehicles such as bulldozers, snow vehicles, and slope maintenance vehicles,
HST (Hydro-Sta) that drives two sets of left and right final reduction gears with two sets of hydraulic pumps and hydraulic motors
tic-Transmission) method exists.
Since the above-mentioned vehicle is not generally required to have a high vehicle speed (about 20 km / h), the output shaft of the hydraulic motor is directly connected to a simple speed reducer having no speed change mechanism.

[0003]

In the above-mentioned HST drive type tracked vehicle, when the rotational speeds of the left and right hydraulic motors are the same, the vehicle goes straight, and when the rotational speeds are different, the vehicle turns right or left. . As described above, the output shaft of the hydraulic motor is connected to the final reduction gear, and there is no clutch for power connection / disconnection between the final reduction gear and the final reduction gear does not have a speed change mechanism. It has no mechanism to engage / disengage power. Therefore, even if the rotational speed commands of the left and right hydraulic motors are the same, the actual rotational speed of the left and right hydraulic motors may differ if there are individual differences in the performance of the left and right hydraulic pumps or hydraulic motors. Therefore, the output shaft rotation speed of the left and right final reducer (equal to the speed of the left and right crawler tracks) will be different. (Because the rotation of the hydraulic motor is simply decelerated by the final reducer.) That is, when the driver tries to start the vehicle while keeping the vehicle straight, the hydraulic pump and the hydraulic motor have the above-mentioned individual differences. In some cases, there is a risk that the vehicle will run right or left immediately after starting, contrary to the driver's will.

An object of the present invention is to solve the above problems and to prevent the vehicle from traveling to the right or left against the intention of the driver who tries to start the vehicle while keeping the straight traveling state immediately after starting the vehicle. It is an object of the present invention to provide a straight-ahead correction control device at the time of starting a drive-type tracked vehicle.

[0005]

A straight-ahead correction control device for a hydraulically driven tracked vehicle according to the present invention comprises two sets of variable displacement hydraulic pumps 3, 4 and variable displacement hydraulic motors 5, 6 on the right and left. A power transmission device for a hydraulically driven tracked vehicle driven by two sets of final reduction gears 7, 8 having the same structure on the right and left, wherein a low speed stage and a high speed stage are arranged in the right and left final reduction gears in the same configuration. The right and left first planetary gear units (right side 10), the right and left second planetary gear units (right side 12), which serve as the transmission mechanism of the first and second planetary gear units, are combined with the first planetary gear unit to change the power and to start and stop Right and left fixed clutches 10-3 and 17, engaged and disengaged, rotary clutches 11 and 18, a hydraulic pump rotation speed detector 24 that outputs a signal related to the operating state of the power transmission device, and right and left hydraulic motor rotations. Speed detector 25,26, right and left Force shaft rotational speed detector 27
And a position selection switch 34 of a speed change lever for outputting a signal relating to a setting condition of a control device of a vehicle, a steering wheel angle detector 36 for steering, and a control for inputting signals from the respective detectors and performing a required signal processing. Device 40 and right and left hydraulic pump control actuators 20, 21, hydraulic motor control actuators 22, 23, fixed clutch actuating actuators 29, 30, whose operation is controlled by commands from respective drive circuits of the control device It has clutch operating clutches 31 and 32, and right and left final reduction gears 7 and 8 incorporate low speed stage fixed clutches 10-3 and 17 and high speed stage rotary clutches 11 and 18, respectively. So
Even when the vehicle is stopped, the rotation speeds of the right and left hydraulic motors 5 and 6 can be fed back to the control device 40 as correction control signals, and the rotation speeds of the right and left hydraulic motors 5 and 6 are both set to zero in advance. When the driver tries to start the tracked vehicle while keeping the straight running state, the vehicle may run to the right or left immediately after starting, contrary to the intention of the driver. The feature is that it can be resolved.

[0006]

[Action]

(1) By adding a power engagement / disconnection mechanism to the final reduction gear for a tracked vehicle driven by a hydraulic pump and a hydraulic motor, the hydraulic motor can be stopped or rotated while the vehicle is stopped. (2) It is possible to electrically detect the rotation of the hydraulic motor and input a feedback signal to an actuator that controls the oil displacement volume of the hydraulic pump. (3) By combining the functions of (1) and (2), it is possible to eliminate the risk that the vehicle will move to the right or left against the driver's will immediately after the vehicle starts moving.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a system configuration diagram of a hydraulic drive system of a tracked vehicle to which a straight-ahead correction control device for starting according to an embodiment of the present invention is applied. The configuration and operation will be described with reference to the drawings. The engine 1 drives variable displacement hydraulic pumps 3 and 4 for driving the right and left final reduction gears via a transfer 2 having a gear train inside. The hydraulic pumps 3 and 4 hydraulically transmit the engine power to the variable displacement hydraulic motors 5 and 6 for driving the right and left final reduction gears via hydraulic pipes, and the hydraulic motors 5 and 6 are connected to the right and left final gears. Drive the speed reducers 7, 8. Since the power transmission mechanisms inside the final reduction gears 7 and 8 are the same, only the power transmission mechanism of the right final reduction gear 7 will be described below.

The output shaft 9 of the right variable displacement hydraulic motor 3 is
Through the gear train, the sun gear 10 of the first planetary gear device 10
The rotational power is transmitted to -1. The ring gear 10-2 is connected to a fixed clutch 10-3 that engages / disengages power with a hydraulic piston provided in the housing of the right final reduction gear 7. The carrier 10-4 and the sun gear 10-1 are provided with a rotary clutch 11 for engaging / disengaging the power with a hydraulic piston.
Is attached. The carrier 10-4 is connected to the sun gear 12-1 of the second planetary gear device 12. The ring gear 12-2 is fixed to the housing of the right final reduction gear 7. A brake device 13 that operates with a hydraulic piston or the like is attached to the end of the carrier 10-4, and the carrier 12-3
Is the output shaft 14 of the right final reduction gear 7. The output shaft 14 is
Coupled with the right actuation wheel 15, the actuation shaft 15 turns the track,
It will propel the vehicle.

The right final reduction gear 7 is a two-stage switching type transmission having a low speed stage and a high speed stage. That is, when the low speed stage is requested, the fixed clutch 10-3 is operated in the power engagement state and the rotary clutch 11 is not operated in the power disengagement state. In this combination, the first planetary gear device 10 becomes a reduction gear having a fixed reduction ratio i ₁ of the ring gear. Further, also in the second planetary gear device 12,
A reduction gear having a fixed ring gear reduction ratio i ₂
Output shaft 9 of variable displacement hydraulic motor 5 and sun gear 12-1
When the reduction gear ratio i ₃ of the gear train between the two is incorporated, the transmission has a total reduction gear ratio i _L = i ₁ × i ₂ × i ₃ . Therefore, the rotation speed of the output shaft 9 of the variable displacement hydraulic motor 5 is i _L
The speed is reduced at a ratio of, and the right starting wheel 15 is rotated at a low speed.

When a high speed stage is required, the fixed clutch 10-3 is deactivated and the rotary clutch 11 is activated to bring it into a power engaged state. In this combination, the first planetary gear device 10 rotates the sun gear 12-1 of the second planetary gear device 12 in a state where the sun gear 10-1 and the carrier 10-4 are directly connected to each other. That is, the total reduction ratio i
The transmission is _H = 1 × i ₂ × i ₃ . Therefore, the rotation speed of the output shaft 9 of the variable displacement hydraulic motor 5 is decelerated at a rate of i _H , and the right starting wheel 15 is rotated at a high speed.
The structure described above is the same in the left final reduction gear 8 as described above.

When the hydraulic drive system for a tracked vehicle using such a power transmission system is used, the right and left final reduction gears 7, 8 are used.
When the speed stages are the same and the rotation speeds of the right and left variable displacement hydraulic motors 5 and 6 are the same, the rotation speeds of the right and left starting wheels are the same, and therefore the vehicle goes straight. When the rotational speeds of the variable displacement hydraulic motors 5 and 6 are different, the rotational speeds of the right and left starting wheels are also different, so the vehicle turns to the right or left. When both the fixed clutch 10-3 and the rotary clutch 11 are in the non-operating state, the final reduction gear is in a neutral state in which the rotational power is not transmitted even if the output shaft of the variable displacement hydraulic motor is rotating. . That is, the vehicle remains stopped. When the brake device 13 is activated, the output shaft 14 is fixed and the vehicle is controlled. As described above, the structure of the left final reduction gear 8 is the same as that of the right final reduction gear 7. Reference numeral 16 is an output shaft of the left hydraulic motor, 17 is a fixed clutch, 18 is a rotary clutch, and 19 is an output shaft of the left final reduction gear.

Reference numerals 20 and 21 are pump control actuators for controlling the displacement volumes of the right and left variable displacement hydraulic pumps, and 22 and 23 are motors for controlling the displacement volumes of the right and left variable displacement hydraulic motors. It is a control actuator and is operated by an electric control signal from the control device 40. As the actuators 20 to 23, specifically, an electrohydraulic proportional control valve or the like is used. Reference numeral 24 is a hydraulic pump rotation speed detector that detects the rotation speed of the left and right variable displacement hydraulic pumps, and 25 and 26 are right (left) hydraulic motor rotation speed detectors that detect the rotation speeds of the right and left variable displacement hydraulic motors. , 27 and 28 are right (left) output shaft rotation speed detectors that detect the rotation speeds of the right and left final reduction gear output shafts, and these rotation speed detectors 24 to 28 output electrical rotation speed signals. Output to the control device 40. 29 and 30 are right (left) fixed clutch actuating actuators, 31 and 32 which are operated by electric control signals from the control device 40 to engage / disengage (release) the right and left fixed clutches.
Is a right (left) rotary clutch actuating actuator that is actuated by an electrical control signal from the control device 40 to engage / disengage the right and left rotary clutches. A solenoid valve or the like is specifically used for these actuators.

Reference numeral 33 is an accelerator pedal position detector for electrically detecting the depression amount of the accelerator pedal. Reference numeral 34 is for electrically detecting the positions of the position selector lever such as forward, backward, neutral, and super turning. A position selection switch for extracting a corresponding signal, 35 is a brake pedal position detector for electrically detecting the depression amount of the brake pedal, and 36 is a steering wheel angle detection for electrically detecting a steering wheel operation angle for turning the vehicle. It is a vessel. Each electric signal from these detectors and switches is input to the control device 40.

FIG. 2 is an explanatory view of a gear shift method of a hydraulic drive system for a tracked vehicle to which the control system according to the embodiment of the present invention is applied. (1) Stopped state: As described above, in the stopped state, the left and right low speed stage fixed clutches 17 and 10-3 and the left and right high speed stage rotary clutches 18 and 11 are in the disengaged state, respectively. At this time, the oil displacement volumes of the left and right variable displacement hydraulic pumps are set to 0 cc / rev, and at the same time, the displacement volumes of the left and right variable displacement hydraulic motors are set to α · q _Mmax cc / rev.
(0 <α <1, q _Mmax : maximum displacement of hydraulic motor). (2) Low speed and later: left and right low speed fixed clutches 17,
10-3 is brought into an engaged state. In the range of mode 1 shown in FIG. 2 in the low speed stage, the displacement volume of the left and right hydraulic motors is constant at α · q _Mmax cc / rev, and the displacement volume of the left and right hydraulic pumps is 0 to β · q. _Pmax cc /
By changing to rev (0 <β <1, q _Pmax : maximum displacement of the hydraulic pump), the output shaft rotation speed of the left and right final reduction gears can be increased from 0 to N _A. Even in mode 2 in the low speed stage, mode 3 and mode 4 in the high speed stage, the displacement volumes of the left and right hydraulic pumps and the left and right hydraulic motors are changed as shown in FIG. The rotation speed further increases and reaches N _max .

In the hydraulically driven power transmission system for a tracked vehicle referred to in FIG. 1, a fixed clutch for a low speed stage and a rotary clutch for a high speed stage are built in the final reduction gear. Therefore, with this structure, the rotational speed of the hydraulic motor can be incorporated in the control device as a correction control symbol even when the vehicle is stopped. FIG. 3 shows a block diagram which constitutes a main part of the straight-ahead straight-travel correction control device according to the embodiment of the present invention.
Hereinafter, for simplification of description, a case where the steering wheel angle in the stopped state is in the straight traveling position will be described. Therefore, the steering wheel angle signal from the steering wheel angle detector 36 is transmitted to the controller 4
An angle signal corresponding to 0 is output to 0. The position selection signal a from the position selection switch 34 is input to the neutral judgment logic circuit 41. In 41, the actuators 29, 30, 31, 32 for operating the right and left fixed clutches and the rotary clutch are deactivated (O) only when the position signal a is a = a _N (neutral position signal).
FF) state, and thereby the control signals for disengaging all clutches are provided to the respective clutch actuating drive circuits 48, 49,
Output through 50 and 51. In addition, the control device 40 outputs control signals D _PL and D _PR ( _assuming D _PL = D _PR ) to the left and right hydraulic pump control actuators 21 and 20 so that the displacement volumes thereof become 0. At the same time, the control device 40 controls the left and right hydraulic motor control actuators 2
The displacement volumes of α and q _Mmax are 3 and 22 respectively.
Control signals D _ML and D _MR (D _ML = D _MR )
Is output.

If the left and right hydraulic pumps and the left and right hydraulic motors have individual differences in performance when the engine 1 is in operation, the control device 40 sends the control signal to each of the actuators 20 to 20.
Even if it outputs to 23, either of the left and right hydraulic motors 6 and 5 will rotate. The left and right hydraulic motor rotation speed detectors 26, 25 output the left and right hydraulic motor rotation speed signals N _ML , N _MR to the left and right motor rotation speed comparators 43, 42.
Entered in. The reference values n _Mo corresponding to the hydraulic motor rotation speed of 0 rpm are stored in advance in the comparators 43 and 42, and the respective input signals N _ML and N _MR and the reference value n _Mo are stored.
Deviation (size relationship) Δn _ML = N _ML −n _Mo , and Δn _MR
= N _MR -n _MO is calculated. These deviations are input to the right pump deviation polarity adding circuit 44 and the left pump deviation polarity adding circuit 45, respectively. In these polarity adding circuits, Δn
When> 0, each deviation is multiplied by the polarity of (-), and Δn <0
In the case of, it has a function of multiplying each deviation by the polarity of (+). The polarity deviation signals output from the left and right polarity adding circuits 45 and 44 are input to the left and right hydraulic pump control actuator drive circuits 47 and 46, and then the left and right hydraulic pump control actuators 21 and 20 are supplied with the control signals D _PL and D _PR. Is output as feedback. By the fed back control signal, the displacement volume of the left and right hydraulic pumps is changed from the initial setting, and in this process, the rotational speeds of the left and right hydraulic motors 6 and 5 converge to 0 rpm.

In the above embodiments, the right and left hydraulic pumps 3 and 4 and the hydraulic motors 5 and 6 drive the final reduction gears 7 and 8. However, the battery is used as a power source to drive the final reduction gears by the motors. Also, the configuration of the control device according to the present invention can be applied. Further, although two sets of clutches for low speed and high speed are used for the final reduction gears 7 and 8 of the above-mentioned embodiment, at least one set or two or more sets of clutches for power engagement / disconnection are provided. The control device according to the present invention can be applied to the final reduction gear.

[0018]

With the straight-ahead straight-ahead correction control device of the present invention, immediately after the hydraulically driven vehicle is started, the vehicle is driven right or left against the driver's intention to start the vehicle while keeping the straight-ahead state. The risk of traveling to can be eliminated.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of a hydraulic drive system for a tracked vehicle according to an embodiment of the present invention.

FIG. 2 is a characteristic explanatory view of a speed change method of a hydraulic drive system.

FIG. 3 is a block diagram showing a configuration of a main part of a straight-ahead straight-travel correction control device.

[Explanation of symbols]

1 ... Engine, 2 ... Transfer, 3 ... Right variable displacement hydraulic pump, 4 ... Left variable displacement hydraulic pump, 5 ... Right variable displacement hydraulic motor, 6 ... Left variable displacement hydraulic motor, 7 ... Right end Reducer, 8 ... Left final reducer, 9 ... Right hydraulic motor output shaft, 10 ... Right first planetary gear device, 10-1 ... Sun gear, 10-2 ... Ring gear, 10-3 ... Fixed clutch, 10-4 ... Carrier, 11 ... Rotary clutch, 12 ...
Right second planetary gear device, 12-1 ... Sun gear, 12-2 ...
Ring gear, 12-3 ... Carrier, 13 ... Brake device, 14 ... Right final reduction gear output shaft, 15 ... Right starting wheel, 16 ...
Left hydraulic motor output shaft, 17 ... Fixed clutch, 18 ... Rotating clutch, 19 ... Left final reduction gear output shaft, 20 ... Right hydraulic pump control actuator, 21 ... Left hydraulic pump control actuator, 22 ... Right hydraulic motor control actuator, 2
3 ... Left hydraulic motor control actuator, 24 ... Hydraulic pump rotation speed detector, 25 ... Right hydraulic motor rotation speed detector, 26 ... Left hydraulic motor rotation speed detector, 27 ... Right output shaft rotation speed detector, 28 ... Left Output shaft rotation speed detector, 2
9 ... Actuator for operating right fixed clutch, 30 ... Actuator for operating left fixed clutch, 31 ... Actuator for operating right rotation clutch, 32 ... Actuator for operating left rotation clutch, 33 ... Accelerator pedal position detector, 3
4 ... Position selection switch, 35 ... Brake pedal position detector, 36 ... Steering wheel angle detector, 40 ... Control device, 41 ... Neutral judgment logic circuit, 42 ... Right motor rotation speed comparator, 43 ... Left motor rotation speed comparator , 44 ... right pump deviation polarity addition circuit, 45 ... left pump deviation polarity addition circuit, 4
6 ... Right hydraulic pump control actuator drive circuit, 47 ...
Left hydraulic pump control actuator drive circuit, 48 ... Right fixed clutch operation actuator drive circuit, 49 ... Left fixed clutch operation actuator drive circuit, 50 ... Right rotation clutch operation actuator drive circuit, 51 ... Left rotation clutch operation actuator drive circuit circuit.

Claims (1)

[Claims] 1. Driven by two sets of variable displacement hydraulic pumps (3, 4) on the left and right, variable displacement hydraulic motors (5, 6), and two sets of final reduction gears (7, 8) having the same structure on the right and left. In a power transmission device for a hydraulically driven tracked vehicle, right and left first planetary gear devices (right side 10) that are arranged in the right and left final reduction gears in the same configuration to serve as a speed change mechanism for a low speed stage and a high speed stage. , Right and left second planetary gear units (right side 12),
The right and left fixed clutches (1) that engage / disengage power during gear shifting and start / stop in combination with the first planetary gear device.
0-3, 17), a rotary clutch (11, 18), and a hydraulic pump rotation speed detector (24) that outputs a signal related to the operating state of the power transmission device, and a left and right hydraulic motor rotation speed detector (25, 26). ), The left and right output shaft rotation speed detectors (2
7 and 28) and the position selection switch (3) of the gearshift lever that outputs a signal related to the setting status of the vehicle control device.
4), steering wheel angle detector (36) for steering, control device (40) for inputting signals from each of the detectors and performing required signal processing, and actuated by commands from each drive circuit of the control device The left and right hydraulic pump control actuators (20, 21), hydraulic motor control actuators (22, 23), fixed clutch actuating actuators (29, 30), rotary clutch actuating clutch (3
1, 32) and the right and left final reduction gears (7,
Since the fixed clutch (10-3, 17) and the rotary clutch (11, 18) are built in 8), the rotational speeds of the right and left hydraulic motors (5, 6) are corrected and controlled even when the vehicle is stopped. It can be fed back to the control device (40) as a signal, and both the rotation speeds of the right and left hydraulic motors (5, 6) can be converged to zero in advance so that the driver can keep the straight traveling state. At the start of a hydraulically driven tracked vehicle, the possibility of running the tracked vehicle to the left or right immediately after the start of the tracked vehicle is eliminated when the tracked vehicle is started. Straight ahead correction control device.