JPS59128024A - Constant speed rotation controller of rotor for vehicle such as ready-mix concrete truck - Google Patents

Abstract

PURPOSE:To elevate the stability of a control system against turbulance by performing a feedback control according to revolutions of a hydraulic motor for driving a rotor and a feed forward control according to the tilt angle of an accelerator pedal for a variable capacity type hydraulic pump. CONSTITUTION:During the operation of an engine 1, a piston pump 3 operates with the swash angle kept at a specified angle set by a control circuit 10 to discharge a pressure oil and a hydraulic motor 6 is driven by the pressure oil to rotate a rotary drum 2. Here, the revolutions RM of the hydraulic motor 6 are detected with a revolution sensor 8 and inputted into the control circuit 10 to be collated with the target revolution signal RD. According to the deviation obtained, a feedback control is done to alter said swash angle through an electromagnetic proportional solenoid value 4. A tilt angle signal D of an accelerator pedal with a tilt angle sensor 8 is delayed 13 by a specified time and then, inputted into an adder 12. In this manner, according to this signal D, a feed forward control is performed to correct said deviation.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a constant speed control system for a rotating body in a vehicle, such as a rotating drum of a truck mixer (= + concrete mixer vehicle), in which the rotation of a rotating body in a vehicle is controlled to a constant speed by a hydraulic motor. This invention relates to a rotation control device.

Generally, a truck mixer truck mixes the concrete materials put into the rotating drum by rotating a rotating drum while traveling, and mixes the concrete materials put into the rotating drum before reaching the destination.At the destination, the drum is reversed and the mixed concrete is mixed. It is meant to be discharged.

Conventionally, as a rotational drive device for the rotating drum in such a truck mixer vehicle, a variable displacement hydraulic pump driven by an engine and an extraction motor that receives pressure oil from the hydraulic pump to rotationally drive the rotating drum are used. There is a known system in which the rotation of the rotating drum is controlled by changing the amount of pressure oil discharged from the hydraulic pump, and the variable displacement mechanism of the pump is used while being fixed during concrete conveyance.

However, in this conventional system, since the hydraulic pump is used as a fixed displacement type during concrete conveyance, the rotation speed of the hydraulic motor, that is, the rotating drum, changes as the engine rotation changes, causing the engine to run at high speeds. In the operating range, the rotating drum also rotates at high speed, and as a result,
This has a negative effect on the quality of the concrete to be mixed and the life of the drum itself, and also increases the drive loss required for unnecessary rotation of the drum, which in turn causes problems such as deterioration of the running performance of the millimeter vehicle.

Therefore, the above-mentioned hydraulic pump is made into a variable displacement type, such as a swash plate type axial piston pump, and a motor rotation speed sensor is installed to detect the rotation speed of the hydraulic engine (rotating drum). By performing feedback control on the control amount of the variable control member of the pump (the swash plate angle in the case of a swash plate type axial piston pump) in accordance with the rotation speed signal from the sensor, the hydraulic pump remains stable even when the engine speed increases. It is conceivable to keep the amount of pressure oil discharged approximately constant so that the rotary drum can be rotated at a constant speed regardless of fluctuations in engine rotation.

However, in this case, since the oil L pump is feedback-controlled according to the rotational speed signal of the hydraulic motor (rotating drum), it is possible to stably control the hydraulic motor in relation to the control amount of the variable control member of the pump. There is a delay in response to engine speed fluctuations in the hydraulic motor rotation control, and when the engine speed changes rapidly, the control amount of the pump's variable control member accurately follows the fluctuation and does not change. There is a problem in that the amount of pressure oil discharged from the pump fluctuates, and the rotational speed of the rotary drum also fluctuates drastically.

In view of this, the present invention has a basic configuration in which the control amount of the variable control member in the variable displacement cedar hydraulic pump is feedback-controlled in accordance with the rotation speed of the hydraulic motor as described above, and the control system is configured as a closed loop. Furthermore, it has a feedforward control that corrects the closed loop control according to the tilt angle of the accelerator pedal corresponding to the actual engine speed, and improves the responsiveness of the hydraulic pump to engine speed fluctuations. By increasing the speed of the rotating drum (rotating body), the speed of the rotating drum (rotating body) can be maintained at a constant speed. The purpose of this is to demonstrate the effectiveness of rotation control.

Therefore, the configuration of the present invention includes a variable passenger compartment type hydraulic pump driven by an engine, a φ hydraulic motor that receives pressure oil from the hydraulic pump and rotationally drives a rotating body installed in a vehicle,
An accelerator pedal tilt angle sensor that detects the tilt angle of the accelerator pedal that controls the operation of the engine, a motor rotation speed sensor that detects the rotation speed of the extraction motor, a target rotation number ORO, and a motor rotation speed sensor. The deviation signal from the motor rotation speed output signal @RM is corrected by the output signal from the accelerator pedal tilt angle hinger described in Ila, and the hydraulic pump is controlled to keep the rotation speed of the hydraulic motor constant based on this corrected signal. This system is equipped with a control circuit that controls the amount of pressurized oil discharged until the hydraulic pump operation is feedback-controlled according to the rotation speed of the hydraulic motor, creating a closed-loop control system. The feedforward control is also used to correct the engine speed corresponding to the tilt angle.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

Fig. 1 shows a schematic configuration when the present invention is applied to a Truck Me 1 The vehicle (= 1 concrete mixer vehicle); (1) is an onboard engine of a truck mixer vehicle;
The operation is controlled according to the tilt angle (depression amount) of 2). In addition, (3) is a rotating drum as a rotating body installed in the width of the mixer, which mixes the =1 concrete material put inside by rotating in the normal direction, and discharges the mixed concrete by rotating in the reverse direction.

(4) is a swash plate type axial piston pump as a variable displacement pump driven by the engine (1), and although not shown, the piston pump (4) is rotatable with respect to the input shaft. It has a swash plate, and the amount of pressure oil discharged is changed and controlled by changing the tilting angle of the first plate, that is, the swash plate angle, and changing the push volume of each built-in piston. Furthermore, the piston pump (4) is equipped with an electromagnetic proportional solenoid valve (5) whose spool moves in proportion to the input current, and the electromagnetic proportional solenoid valve (5) controls the piston pump (4). The hydraulic pressure is controlled to change the angle of the swash plate, that is, the amount of pressure oil discharged from the piston pump (4), and to switch the direction of pressure oil discharge.

Further, (6) is a constant volume boat-shaped hydraulic motor capable of forward and reverse rotation, and the output shaft (6a) of the motor (6) is drivingly connected to the rotating drum (3). , and a hydraulic motor (6
) is the pressure oil passage (7).

It is connected to the screw pump (4) through the piston pump (7), and the hydraulic motor (6) is rotated in forward and reverse directions by the pressure oil supplied from the piston pump (4), thereby rotating the rotary drum (3). I'm trying to drive it.

Further, (8) is an accelerator pedal tilt angle sensor that detects the tilt angle of the accelerator pedal (2), and (9) is the number of rotations of the hydraulic motor (6) (the number of rotations of the rotating drum (3)).
The motor rotation speed sensor (10) is a control circuit that receives output signals from the respective sensors (Ji8) and (9) and controls the amount of pressure oil discharged from the piston pump (4). , the control circuit (10), as shown in the block diagram in FIG.
) and a PID converter <11) that converts the deviation signal from the motor rotation speed signal RM into proportional, integral and differential elements, and the tilt angle signal from the accelerator pedal tilt angle sensor v (8).
A delay element (13) (U delay circuit) that corrects the delay by a predetermined time corresponding to the response variation of the engine rotational speed to the tilt variation of the accelerator pedal (2), and the delay element (13)
) into a corresponding output signal.
Transfer element ('+4) and the PID converter (11)
and the output signal from the first transmission element (14) are added by the adder (12) and converted into a corresponding output signal for controlling the electromagnetic proportional solenoid valve (5). ). Therefore, the output signal from the motor rotation speed sensor (9) <motor rotation speed signal RM
) and the target rotational speed signal RO is corrected using the output signal (tilting angle signal D) from the accelerator pedal tilting angle sensor (8) to keep the rotational speed of the hydraulic motor (6) constant. It is configured to control the pressure oil leaf Wm of the piston pump (4).

Next, to explain the operation of the above embodiment, as the engine (1) operates, the piston pump (4)
Pressure oil is discharged by operation while maintaining a predetermined swash plate angle set by the circuit (10), and the pressure oil discharged from this pump (4) passes through one pressure oil passage (7). The oil is supplied to the hydraulic motor (6) to drive and rotate the hydraulic motor (6), and the rotation of the motor (6) causes the oil to flow into the rotating drum (3).
rotates to mix concrete, etc.

At that time, the rotation speed of the hydraulic motor (6) is detected by the Seven-Taro rotation speed sensor (9) and inputted to the control circuit (1o) as a motor rotation speed signal RM. The control circuit (10) that receives the motor rotation speed signal RM compares the motor rotation speed signal RM with the target rotation signal Ro of the hydraulic motor (6), and when there is a difference between the two signals RM and RO, it controls the current according to the deviation. Signal electromagnetic proportional solenoid valve (5)
Change the swash plate angle of the piston pump (4) by changing the angle of the piston pump (4).
As a result, the amount of pressure oil discharged from the pump (4) is changed by a predetermined amount, and the rotation speed of the hydraulic motor (6) is corrected to the target rotation speed. That is, the piston pump (4) is feedback-controlled according to the rotation speed of the hydraulic motor (6>), and closed-loop control is performed.

On the other hand, the tilt angle of the accelerator pedal (2) at that time is detected by the accelerator pedal tilt angle sensor (8) and inputted to the control circuit (1o) as a tilt angle signal, and this tilt angle signal is used for control. After the delay is corrected by the delay element (13) in the circuit (1o), the electromagnetic proportional solenoid valve (5)
The output signal supplied to the engine is corrected according to the engine speed. That is, the feedback-controlled piston pump (4) is also feedforward controlled in response to rotational fluctuations of the engine (1). With this feedforward control, when the tilt angle of the accelerator pedal (2) changes rapidly and the engine speed fluctuates rapidly, the swash plate angle of the piston pump (4) is inversely proportional to the increase or decrease in the engine speed. Pump (4
) is approximately constant. As a result of the above, the hydraulic motor (6) rotates at a constant speed regardless of rotational fluctuations of the engine (1).

Therefore, in this way, the operation of the piston pump (4) is controlled in a closed loop, and the rotational fluctuations of the engine (1) are controlled in a feedforward manner.
The operation of the pump (4) can be controlled with high precision, and the responsiveness to rotational fluctuations of the engine (1) is improved to compensate for the drawbacks of the closed-loop control, resulting in stability against external disturbances. Therefore, the rotating drum (3) can always be rotated stably and accurately at a constant speed. Moreover, this makes it possible to reduce the extra driving loss of the truck mixer vehicle as much as possible, thereby improving driving performance, saving fuel consumption, and saving energy.

In addition, at this time, in order to delay correct the tilt angle signal from the accelerator pedal tilt angle sensor (8) in the control circuit (10),
Engine response to changes in the tilt of the accelerator pedal (2) [1]
) is compensated for the response delay due to rotational fluctuations, and the piston pump (
The control for 4) can be made to correspond accurately to the rotational fluctuations of the engine (1), so that the rotating drum 3) can be more reliably stopped from rotating at a constant speed.

Furthermore, in order to change and control the swash plate angle of the piston pump (4) according to changes in the tilt angle of the accelerator pedal (2), the engine speed is directly detected by a speed sensor and the engine speed is adjusted according to the engine speed. Compared to controlling the swash plate angle of the pump by changing it, there is no need for an expensive rotation speed sensor or an f-v conversion circuit for converting the output pulse signal from the rotation speed sensor into voltage. It can be manufactured at low cost.

In the above embodiment, a swash plate type axial piston pump (4) in which the pressure oil discharge amount changes by changing the swash plate angle was used as the variable displacement hydraulic pump, but other types such as a variable displacement radial piston pump or Of course, various types of hydraulic pumps such as vane pumps may be used.

It goes without saying that the present invention can be applied not only to the truck mixer as in the embodiment described above, but also to various types of vehicles equipped with rotating bodies that rotate at a constant speed.

As explained above, according to the present invention, a variable displacement hydraulic pump is rotationally driven by an engine, and one
1. In a rotary drive device for a rotary body in a vehicle in which the hydraulic motor is operated by the output oil to rotate the rotary body, the hydraulic motor is controlled so that the rotary body rotates at a constant speed to control the operation of the hydraulic pump. Feedback control is performed according to the engine speed, and feedforward control is also performed according to the accelerator pedal tilt angle corresponding to the engine speed, making it possible to quickly and accurately control the pump operation in response to engine speed fluctuations. This can improve the stability of the control system against external disturbances, thereby effectively contributing to improving the quality of products such as concrete, improving the driving performance of vehicles, and saving energy.

Furthermore, if the tilt angle signal is delayed and corrected without indicating the tilt angle of the accelerator pedal, it is possible to compensate for the response of engine rotational changes to changes in the tilt angle of the accelerator pedal. can be rotated at a constant speed even more accurately, and the above-mentioned effects can be enhanced.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is an overall schematic explanatory diagram, and FIG. 2 is a block diagram of a control system.

Claims (2)

[Claims] (1) A variable sound fit type hydraulic pump (4) driven by an engine (1) and a rotary body (3) installed in a vehicle by pumping oil from the hydraulic pump (4). an accelerator pedal tilt angle sensor (8) that detects the tilt angle of the accelerator pedal (2) that controls the operation of the engine (1); (6)
correcting the output signal from the motor rotation speed sensor (9) and the motor rotation speed sensor (9) with the output signal from the accelerator pedal tilt angle sensor (8);
It is characterized by comprising a control circuit (10) that controls the amount of pressure oil discharged from the hydraulic pump (4) so as to keep the rotation speed of the hydraulic motor (6) constant based on the corrected signal. Constant speed rotation control device for rotating bodies in vehicles such as truck mixers. (2) The control circuit (10) includes a d delay circuit (13) that delays and corrects the output j signal from the accelerator pedal tilt angle sensor (8).
) A constant-speed rotation control device for a rotating body in a vehicle such as a truck mixer truck according to claim (1).