JP2005069372A - Hydraulic control device for working vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve working efficiency of a hydraulic device by reducing influence of operation of the hydraulic device to peripheral environment as much as possible, preventing waste of energy and reducing burden to an operator. <P>SOLUTION: This hydraulic control device is structured of the hydraulic device 14 loaded on a working vehicle, a first hydraulic pump 12 to be driven by a vehicle engine 10 to supply an operating fluid to the hydraulic device 14, an electric motor 22 to be driven by an external power source, a second hydraulic pump 24 to be driven by the electric motor 22 to supply the operating fluid to the hydraulic device 14, an operation detecting means 32 for detecting operating condition of the hydraulic device 14 to output a result of detection to a control unit 26, and the control unit 26 for controlling the electric motor 22 in response to the result of detection of the operation detecting means 32. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a hydraulic control device for a work vehicle that controls supply of hydraulic oil to a hydraulic device mounted on the work vehicle.

  The working vehicle is equipped with hydraulic equipment for work such as a crane, and the hydraulic engine is driven by the vehicle engine of the working vehicle, and hydraulic oil is supplied from the hydraulic pump to the actuator of the hydraulic equipment through the control valve. Activate the equipment. When a hydraulic pump is driven by a vehicle engine, noise and exhaust gas are generated from the vehicle engine, and this noise and exhaust gas affect the environment around the work site. In particular, when working in an urban area or the like, it is required to reduce as much as possible noise and exhaust gas generated from a vehicle engine in order to suppress the influence on the environment as much as possible.

  There is a hydraulic power unit system for a working vehicle shown in FIG. 5 as a technique for reducing noise and exhaust gas emitted to the surrounding environment when operating a hydraulic device mounted on the working vehicle (see Patent Document 1). The work vehicle hydraulic power unit system 102 includes a work vehicle 104, a hydraulic power unit 120, and a hydraulic pipe 128. The work vehicle 104 is operated by a vehicle engine 110 whose rotation speed is controlled by an accelerator pedal 141, a first hydraulic pump 112 driven by the vehicle engine 110, and hydraulic oil supplied from the first hydraulic pump 112. 114.

  The hydraulic power unit 120 includes an electric motor 122 driven by an external power source and a second hydraulic pump 124 driven by the electric motor 122. The hydraulic pipe 128 is configured to be able to supply hydraulic oil discharged from the second hydraulic pump 124 of the hydraulic power unit 120 to the hydraulic equipment 114 of the work vehicle 104. In addition, the work vehicle 104 has an operation position detecting unit 132 for the accelerator pedal 141, and the hydraulic power unit 120 has a control device 126, and based on a signal input from the operation position detection unit 132 to the control device 126, The rotation speed is controlled.

  When operating the hydraulic equipment 114 at a work site in an urban area or the like, the engine 110 of the work vehicle 104 is stopped, power is supplied from the external power source to the hydraulic power unit 120, and the motor 122 is driven by the power from the external power source. The hydraulic oil discharged from the second hydraulic pump 124 is supplied to the control valve of the hydraulic device 114. The electric motor 122 is started and stopped by an operator operating a switch 142 installed near the cockpit of the work vehicle 104. Further, the rotational speed of the electric motor 122 changes according to the amount of depression of the accelerator pedal 141 by the operator, and the flow rate of the hydraulic oil discharged from the second hydraulic pump 124 changes.

As an external power source, a commercial power source, a low noise type engine generator, or the like is used.
When a commercial power source is used as an external power source, unless the operator switches the switch 142, the electric motor 122 continues to operate while the hydraulic device 114 is interrupted, and electric power is wasted by the electric motor 122. No. 2 hydraulic pump 124 generates unnecessary noise. Moreover, since the electric motor 122 continues to operate, the hydraulic oil continues to circulate, the oil temperature rises, and the working efficiency of the hydraulic device 114 is deteriorated. Therefore, when the hydraulic equipment 114 is frequently operated with a stop, the operator must frequently switch the switch 142 to start and stop the motor 122.

When a low noise type engine generator is used as an external power source, noise and exhaust gas are also generated from the engine generator. Therefore, unless the operator switches the switch 142 of the electric motor 122 and the switch of the engine generator, respectively, the engine generator and the electric motor 122 continue to operate while the hydraulic equipment 114 is suspended, and the engine generator generates fuel. Is wasted, electric power is wasted by the electric motor 122, and unnecessary noise and exhaust gas are generated from the engine generator, the electric motor 122, and the second hydraulic pump 124. Further, the hydraulic oil continues to circulate and the oil temperature rises. When the hydraulic device 114 is frequently operated with a stop, the operator must frequently switch the switch 142 of the electric motor 122 and the switch of the engine generator.
Japanese Patent No. 3330908

However, in the hydraulic power unit system 102 of the work vehicle described above, when the operator frequently switches the switch 142 of the electric motor 122 or the switch of the engine generator, the amount of work other than the operation of the hydraulic device 114 that the operator should originally perform increases. This increases the burden on the operator and increases operator fatigue.
The present invention has been made to solve the above-mentioned problems, and its object is to minimize the influence on the surrounding environment due to the operation of the hydraulic equipment, to prevent waste of energy, and to reduce the burden on the operator. It is providing the hydraulic control apparatus of the working vehicle which improves the working efficiency of this.

  The present invention adopts the following configuration in order to solve the problem. A hydraulic control apparatus for a work vehicle according to a first aspect of the present invention is driven by a hydraulic device mounted on the work vehicle, a first hydraulic pump that is driven by a vehicle engine and supplies hydraulic oil to the hydraulic device, and an external power source. An electric motor, a second hydraulic pump driven by the electric motor to supply hydraulic oil to the hydraulic equipment, an operation detection means for detecting an operation state of the hydraulic equipment and outputting the detection result to the control unit, and an operation detection means And a control unit that controls the electric motor according to the detection result.

  According to the invention of claim 1, when working in an urban area or the like, the vehicle engine is stopped and an external power source is used. The operation detecting means detects the operation state of the hydraulic device and outputs the detection result to the control unit. The control unit operates the electric motor according to the detection result and also operates the second hydraulic pump. The electric motor and the second hydraulic pump are operated only while is operating. There is no need for the operator to directly start and stop the motor with a switch.

A hydraulic control device for a work vehicle according to a second aspect of the present invention is the hydraulic control device for a work vehicle according to the first aspect, wherein the engine generator is driven by the control unit in accordance with the detection result of the operation detection means. Is used as an external power source.
According to the invention of claim 2, when power is supplied from the engine generator to the electric motor, the control unit operates the engine generator, the electric motor, and the second hydraulic pump only while the hydraulic equipment is operating. However, it is not necessary to directly operate the engine generator and the motor with switches.

A hydraulic control device for a work vehicle according to a third aspect of the invention is the hydraulic control device for a work vehicle according to the first or second aspect, wherein an accumulator that releases hydraulic oil to a hydraulic device when the electric motor is started is provided. Prepare.
According to the third aspect of the invention, when the second hydraulic pump starts operating, the hydraulic oil is immediately discharged from the accumulator to the hydraulic equipment at the predetermined pressure before the discharge pressure of the second hydraulic pump reaches the predetermined pressure. The Therefore, it is not necessary to wait for the discharge pressure of the second hydraulic pump to reach a predetermined pressure, and a delay in response of the hydraulic equipment is prevented.

  The hydraulic control apparatus for a work vehicle according to the present invention has a very small influence on the surrounding environment due to the operation of the hydraulic equipment, prevents waste of energy, reduces the burden on the operator, and improves the working efficiency of the hydraulic equipment. There is an effect.

An example of the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a configuration diagram of a hydraulic control device for a work vehicle according to the present embodiment.
A vehicle engine 10, a first hydraulic pump 12, a hydraulic device 14, a hydraulic power unit 20, and an operation detection unit 32 are mounted on a work vehicle (not shown).
The first hydraulic pump 12 is driven by the vehicle engine 10 so as to pressurize the hydraulic oil in the hydraulic oil tank 30 and discharge it to the hydraulic oil line 28a.
The hydraulic equipment 14 is various working equipment such as a crane, for example, and includes a hydraulic actuator 18 and a control valve 16 for operating the hydraulic equipment 14. The hydraulic oil flows from the hydraulic oil line 28a to the hydraulic actuator 18 through the control valve 16, and the return oil from the hydraulic actuator 18 flows through the control valve 16 and the hydraulic oil line 28b to return to the hydraulic oil tank 30. ing.

  The hydraulic power unit 20 includes an electric motor 22, a second hydraulic pump 24, and a control unit 26. The electric motor 22 is, for example, an induction motor or the like, and the control unit 26 includes an inverter circuit (not shown) for driving the electric motor and a timer (not shown), and the control unit 26 sends a start signal S1 to the electric motor 22 and stops. The signal S2 is output so that the start and stop of the electric motor 22 can be controlled. The second hydraulic pump 24 is driven by the electric motor 22 so as to pressurize the hydraulic oil in the hydraulic oil tank 30 and discharge it to the hydraulic oil line 28a. The control unit 26 of the hydraulic power unit 20 can be connected to a commercial power source 34 that is an external power source, and is configured to receive power supply from the commercial power source 34.

  The operation detection means 32 has a micro switch (not shown) that detects the movement of the main spool (not shown) of the control valve 16, and the control unit detects the movement of the main spool detected by the micro switch as the operation state of the hydraulic device 14. 26 is configured to be able to output to H.26. The signal output from the operation detecting means 32 to the control unit 26 indicates that the main spool is at the operating position of the hydraulic device 14 and the operating position signal S3 indicating that the main spool is at the operating position of the hydraulic device 14. This is the stop position signal S4 shown. The operating position of the hydraulic device 14 taken by the main spool is a position where the operator operates the control valve 16 to move the main spool from the neutral position and connect the hydraulic oil line 28a to the hydraulic actuator 18. Say. The stop position of the hydraulic device 14 taken by the main spool means a neutral position where the main spool shuts off the hydraulic oil line 28a when the operator stops the operation of the control valve 16.

Further, when the stop position signal S4 is input from the operation detection means 32 to the control unit 26, the timer of the control unit 26 is activated, and after a predetermined time has elapsed from the input of the stop position signal S4, the stop signal S2 is transmitted to the control unit. 26 is output to the electric motor 22.
Next, the operation of the hydraulic control device for the work vehicle will be described.
A case will be described in which work is started by operating the hydraulic equipment 14 mounted on a work vehicle at a work site in an urban area. First, the operator stops the vehicle engine 10 of the work vehicle at the work site, connects the hydraulic power unit 20 to the commercial power supply 34, and enables power supply to the hydraulic power unit 20.

  Then, the operator manually operates the control valve 16 to switch the control valve 16 to the operating position of the hydraulic device 14. When the main spool of the control valve 16 moves, this movement is detected by the micro switch of the operation detecting means 32, and an operation position signal S3 indicating that the main spool of the control valve 16 is in the operating position of the hydraulic equipment 14 is detected by the operation detecting means. 32 to the control unit 26.

When the operation position signal S3 is input to the control unit 26, the control unit 26 outputs a start signal S1 to the electric motor 22. The electric motor 22 is started by receiving a start signal S 1 from the control unit 26, and the second hydraulic pump 24 is also started by the electric motor 22.
When the second hydraulic pump 24 is started, the hydraulic oil is drawn from the hydraulic oil tank 30 by the second hydraulic pump 24, pressurized, and discharged to the hydraulic oil line 28a. The hydraulic oil discharged to the hydraulic oil line 28a flows into the hydraulic actuator 18 from the control valve 16, and the hydraulic equipment 14 operates. The return oil from the hydraulic actuator 18 returns to the hydraulic oil tank 30 through the control valve 16 and the hydraulic oil line 28b. While the main spool of the control valve 16 is in the operating position of the hydraulic device 14, the electric motor 22 and the second hydraulic pump 24 continue to operate, and the operating oil circulates between the hydraulic oil tank 30 and the hydraulic device 14. Flowing.

In addition, a slight noise is generated from the operating electric motor 22 and the second hydraulic pump 24.
When stopping the operation of the hydraulic device 14, the operator manually operates the control valve 16 to switch the control valve 16 to the stop position of the hydraulic device 14. When the main spool of the control valve 16 moves, this movement is detected by the micro switch of the operation detecting means 32, and a stop position signal S4 indicating that the main spool of the control valve 16 is at the stop position of the hydraulic device 14 is detected by the operation detecting means. 32 to the control unit 26.

When the stop position signal S4 is input to the control unit 26, the timer of the control unit 26 operates, and the control unit 26 outputs the stop signal S2 to the electric motor 22 after a predetermined time has elapsed from the input of the stop position signal S4. The electric motor 22 stops when the stop signal S <b> 2 is input from the control unit 26, and the second hydraulic pump 24 stops together with the electric motor 22.
Since the timing at which the stop signal S2 is output to the electric motor 22 is delayed by a predetermined time from the timing at which the stop position signal S4 is input to the control unit 26, the control valve 16 is switched to the stop position of the hydraulic device 14. In addition, the electric motor 22 and the second hydraulic pump 24 continue to operate for a predetermined time. In the case where the hydraulic device 14 is operated again in a short time after the operation of the hydraulic device 14 is stopped, the second hydraulic pump 24 is in an operating state, and the hydraulic oil is continuously sent to the hydraulic device 14 at a predetermined pressure. Yes. Therefore, there is no need to wait until the pressure of the hydraulic oil discharged from the second hydraulic pump 24 to the hydraulic oil line 28a reaches a predetermined pressure, and the response delay of the hydraulic actuator 18 of the hydraulic device 14 is eliminated.

In addition, since the control unit 26 starts and stops the electric motor 22 when working using the hydraulic equipment 14, the burden and fatigue on the operator are reduced, and the operator can concentrate on the operation of the control valve 16, and the hydraulic equipment 14 The work by is done smoothly. When the hydraulic device 14 is not operating, the electric motor 22 and the second hydraulic pump 24 are stopped. Therefore, unnecessary noise is not generated from the electric motor 22 and the second hydraulic pump 24, and the temperature of the hydraulic oil The rise can also be prevented, and the working oil can be prevented from deteriorating due to the temperature rise of the hydraulic oil.
In the present embodiment, the hydraulic power unit 20 is mounted on the work vehicle. However, the hydraulic power unit 20 is not mounted on the work vehicle and can be a separate unit independent of the work vehicle. Of course.

  Further, in the present embodiment, the micro switch of the operation detecting means 32 detects the mechanical movement of the main spool of the control valve 16, but instead, the micro switch of the operation detecting means 32 operates the hydraulic device 14. It is also possible to adopt a configuration for detecting the mechanical movement of the lever. It is also possible to use a limit switch instead of the micro switch for the operation detection means 32, and this limit switch detects the mechanical movement of the main spool of the control valve 16 and the operation lever of the hydraulic device 14. Specifically, for example, limit switches are provided at both ends of the control valve 16 in the moving direction of the main spool, and the positions of both ends of the main spool can be detected by this limit switch, and the limit switch is activated when the main spool moves. It can be configured. In addition, a position detector such as a differential transformer is provided at one end of the main spool of the control valve 16, and a displacement amount when the main spool moves is calculated by the position detector, and the main spool is The operation detection means 32 may be configured to detect whether the hydraulic device 14 is in the operating position or the stop position.

  When the hydraulic device 14 is remotely operated, for example, the transmission source or relay point of the remote operation signal sent to the control valve 16 of the hydraulic device 14 is used as the operation detection means 32, and instead of the operation position signal S3 and the stop position signal S4. Alternatively, the remote control signal may be output to the control unit 26 and the motor 22 may be controlled by outputting the start signal S1 and the stop signal S2 from the control unit 26 to the motor 22 based on the remote control signal.

  2, the accumulator 36 is connected to the hydraulic oil line 28a on the discharge side of the first hydraulic pump 12 and the second hydraulic pump 24, and the control unit 26 controls the accumulator control valve 38 as shown in the first modification of FIG. It is also possible to adopt a configuration in which the accumulator 36 is controlled via this. When the first hydraulic pump 12 or the second hydraulic pump 24 is operated, the hydraulic oil discharged from these hydraulic pumps also flows into the accumulator 36 and is accumulated. When the control unit 26 outputs the start signal S1 to the electric motor 22, the control unit 26 outputs a hydraulic oil release signal S5 to the accumulator control valve 38 at the same time. When the discharge signal S5 is input to the accumulator control valve 38, the accumulator control valve 38 discharges hydraulic oil having a predetermined pressure from the accumulator 36 to the hydraulic oil line 28a. Therefore, even if it takes time until the hydraulic oil discharged from the second hydraulic pump 24 to the hydraulic oil line 28a reaches a predetermined pressure after the electric motor 22 and the second hydraulic pump 24 are started by the start signal S1, The hydraulic oil having a pressure sufficient to operate the hydraulic actuator 18 of the hydraulic device 14 is immediately sent to the hydraulic oil line 28a, and the operation response of the hydraulic actuator 18 is improved.

  Further, in the present embodiment, the external power source is the commercial power source 34, but the external power source may be a low noise type engine generator 40 as shown in the second modification of FIG. In the second modification, a start signal S1 and a stop signal S2 are output from the control unit 26 to the electric motor 22, and a start signal S6 and a stop signal S7 are output from the control unit 26 to the engine generator 40. However, the operation of the electric motor 22 and the engine generator 40 can be controlled. When the operation position signal S3 is input from the operation detection unit 32, the control unit 26 first outputs a start signal S6 to the engine generator 40. The engine generator 40 is started by a start signal S6 and starts supplying power to the electric motor 22 of the hydraulic power unit 20. Then, the control unit 26 outputs a start signal S1 to the electric motor 22, the electric motor 22 is started by the start signal S1, and the second hydraulic pump 24 is also started. The engine generator 40 in operation generates noise and exhaust gas, although it is at a low level compared to the vehicle engine 10 in operation. When the control unit 26 receives the stop position signal S4 from the operation detection means 32, the timer of the control unit 26 operates, and after a predetermined time has elapsed, the stop signal S2 is output from the control unit 26 to the motor 22 and the stop signal S7. Is output from the control unit 26 to the engine generator 40, and the electric motor 22, the second hydraulic pump 24, and the engine generator 40 are stopped. Therefore, the electric motor 22, the second hydraulic pump 24, and the engine generator 40 are operated until they are unnecessary, so that noise and exhaust gas are not generated, and the operator adjusts the rotational speed of the electric motor 22 and controls the control valve. All you need to do 16 operations.

Further, as shown in Modification 3 in FIG. 4, in Modification 2, as in Modification 1, the accumulator 36 is provided in the hydraulic oil line 28 a on the discharge side of the first hydraulic pump 12 and the second hydraulic pump 24. By connecting, the control unit 26 can control the accumulator 36 via the accumulator control valve 38, and the operation responsiveness of the hydraulic actuator 18 can be improved.
In the present embodiment and the first modification, the external power source is the commercial power source 34, and in the second and third modification examples, the external power source is the engine generator 40. However, the external power source is a secondary battery or a fuel cell. Of course, this is possible.

It is a block diagram of the hydraulic control apparatus of the working vehicle which is an example of embodiment of this invention. It is a block diagram of the hydraulic control apparatus of the working vehicle which concerns on the modification 1. FIG. It is a block diagram of the hydraulic control apparatus of the working vehicle which concerns on the modification 2. It is a block diagram of the hydraulic control apparatus of the working vehicle which concerns on the modification 3. It is a block diagram of the hydraulic power unit system of the conventional work vehicle.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Vehicle engine 12 1st hydraulic pump 14 Hydraulic equipment 16 Control valve 18 Hydraulic actuator 20 Hydraulic power unit 22 Electric motor 24 2nd hydraulic pump 26 Control part 28a, 28b Hydraulic oil line 30 Hydraulic oil tank 32 Operation detection means 34 Commercial power supply 36 Accumulator 38 Accumulator control valve 40 Engine generator S1 Motor start signal S2 Motor stop signal S3 Operation position signal S4 Stop position signal S5 Hydraulic oil release signal S6 Engine generator start signal S7 Engine generator stop signal

Claims (3)

  Hydraulic equipment mounted on the work vehicle, a first hydraulic pump driven by the vehicle engine to supply hydraulic oil to the hydraulic equipment, an electric motor driven by an external power source, and hydraulic oil driven by the electric motor to the hydraulic equipment A second hydraulic pump to be supplied; an operation detection unit that detects an operation state of the hydraulic device and outputs the detection result to the control unit; and a control unit that controls the electric motor according to the detection result of the operation detection unit. A hydraulic control device for a work vehicle.   2. The hydraulic control apparatus for a work vehicle according to claim 1, wherein the external power source is an engine generator whose drive is controlled by the control unit in accordance with a detection result of the operation detection means. The hydraulic control device for a work vehicle according to claim 1 or 2, further comprising an accumulator that releases hydraulic oil to a hydraulic device when the electric motor is started.

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