JP2001316078A - Control circuit for work vehicle with hydraulic power unit specifications - Google Patents

Abstract

(57) [Problem] To provide a control circuit of a work vehicle of a hydraulic power unit specification capable of preventing simultaneous driving of a hydraulic power unit and an engine. A hydraulic power unit (7) including an engine (4), hydraulic pumps (5a, 5b) driven by the engine (4), and having a motor (7b) rotated by electric power supplied from the outside and a hydraulic pump (7a) driven by the motor (7b). Can be supplied to the vehicle side via a hose 8 when the hydraulic power unit 7 is driven and the engine 4 is stopped to perform the work. In the control circuit,
Starter key switch 21, hydraulic power unit start switch 22, hydraulic power unit start switch 22
Engine start prohibiting means R1 for interrupting the engine start command signal output from the starter key switch 21 in response to the hydraulic power unit start command signal from the engine.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a control circuit for a working vehicle of a hydraulic power unit specification.

[0002]

2. Description of the Related Art Conventionally, working vehicles such as hydraulic excavators and mobile crane trucks for performing road works and construction works in urban areas have been provided with a hydraulic pump driven by an engine as a power source. The work machine is operated by driving a hydraulic actuator with oil, but it is desired to reduce noise during work in order to improve the environment for the surrounding residents. Further, in recent years, regulations on exhaust gas have been strengthened due to problems concerning the global environment. In addition, there is an indoor work site such as a factory as a work site, and work sites that dislike exhaust gas and noise are increasing.

As a prior art for solving these problems, a hydraulic power unit system for a crane vehicle disclosed in Japanese Patent Publication No. 3-67164 is known. That is, a hydraulic power unit having a plurality of hydraulic pumps and an electric motor for driving the hydraulic pumps is provided separately from the vehicle. The electric motor rotates by being supplied with power from a nearby power supply. The pressure oil discharged from the hydraulic pump is supplied to the vehicle via a hydraulic hose. As a result, it is possible to work while the engine is stopped, no exhaust gas is generated, and the noise can be suppressed to a low level generated from the electric motor or the hydraulic device.

[0004]

However, in the above-mentioned prior art system, there is a risk that the engine may be started while the hydraulic power unit is being driven, or the hydraulic power unit may be started while the engine is being driven. As described above, when the engine and the hydraulic power unit are driven at the same time, the discharge oil of the hydraulic pump on the vehicle side and the discharge oil of the hydraulic pump on the hydraulic power unit merge, and the hydraulic oil such as the hydraulic actuator and the piping is disturbed. It overloads and adversely affects durability. Furthermore,
The oil temperature rises due to the pressure loss due to the increase in the flow rate, and the heat balance deteriorates.In addition, the overrun of the hydraulic actuator occurs due to the increase in the flow rate. It becomes difficult.

[0005] Further, when the work is performed by the hydraulic power unit, the electric circuit on the vehicle side is also used as it is, so that the alarm device can be activated by the vehicle state monitoring function, and the stoppage of the engine causes the following adverse effects.
That is, the air pressure held by the compressor rotated by the engine gradually decreases due to the stop of the engine, and a warning device (a lamp and a buzzer) for a decrease in the air pressure operates. Further, since the engine is stopped, the engine oil pressure is kept low, so that an alarm device (a lamp and a buzzer) for the engine oil pressure drop is activated. Since these states are not abnormal when the engine is stopped, no alarm is required. The alarm lamp may be turned on because the actual air pressure or engine oil pressure is low. However, the continued buzzing of an unnecessary alarm buzzer hinders the operation of the operator.

Further, as in the above-mentioned prior art system,
When the hydraulic power unit does not have an electrical connection with the vehicle, the operation method and operation feeling are different from those of a normal engine-driven work vehicle as described below, so that the burden on the operator increases and the work efficiency decreases. I will. That is, it is necessary to operate the starting and driving of the hydraulic power unit beside the hydraulic power unit. Also, in the crane operation using the engine drive, work is performed using both lever operation and accelerator pedal operation, whereas in the above-mentioned hydraulic power unit system, since the electric motor rotates at a constant speed, work must be performed only by lever operation. In addition, an operator who has become a normal engine-driven operation may feel uncomfortable and work efficiency may be reduced.

An object of the present invention is to provide a control circuit for a working vehicle of a hydraulic power unit specification which solves at least one of the above-mentioned problems.

[0008]

In order to achieve the above object, a first invention is provided with an engine and a hydraulic pump driven by the rotation power of the engine.
Discharge oil of a hydraulic pump of a hydraulic power unit having an electric motor rotated by electric power supplied from the outside and a hydraulic pump driven by the electric motor can be supplied to the vehicle side via a hose, and work is performed by driving the hydraulic power unit. In the control circuit of a hydraulic power unit specification work vehicle that stops the engine when performing the work, a starter key switch that outputs an engine start command signal, and a hydraulic power unit start switch that outputs a hydraulic power unit start command signal An engine start prohibiting means for interrupting an engine start command signal output from a starter key switch in response to a hydraulic power unit start command signal from the hydraulic power unit start switch.

According to the first aspect, it is impossible to start the engine while the hydraulic power unit is being driven.
The engine and hydraulic power unit cannot be driven simultaneously. Thereby, it is possible to prevent the discharge oil from the vehicle-side hydraulic pump driven by the engine from joining with the discharge oil from the hydraulic pump of the hydraulic power unit,
The overload on hydraulic equipment can be prevented and the durability is not adversely affected. Since an increase in the flow rate can be prevented, an increase in oil temperature due to pressure loss can be suppressed, and the heat balance is not adversely affected. Overrun of the hydraulic actuator can be prevented.

According to a second aspect of the present invention, there is provided a hydraulic power unit having an engine and a hydraulic pump driven by the rotational power of the engine, and having a motor driven by electric power supplied from the outside and a hydraulic pump driven by the motor. The hydraulic pump discharge oil can be supplied to the vehicle via a hose, and when the hydraulic power unit is driven to perform work, the engine is stopped and the work is performed. A hydraulic power unit start switch for outputting a hydraulic power unit start command signal; an engine drive detecting means; and a hydraulic power unit for interrupting the hydraulic power unit start command signal output from the hydraulic power unit start switch based on the engine drive signal from the engine drive detecting means. Equipped with start prohibition means It is characterized.

According to the second aspect, it is impossible to start the hydraulic power unit while the engine is running.
The engine and hydraulic power unit cannot be driven simultaneously. Thus, it is possible to prevent the discharge oil from the vehicle-body-side hydraulic pump driven by the engine and the discharge oil from the hydraulic pump of the hydraulic power unit from joining, as in the first invention, and to reduce overload on the hydraulic equipment. It can be prevented without adversely affecting durability. Because it can prevent the flow rate increase
The oil temperature rise due to pressure loss can be suppressed, and the heat balance is not adversely affected. Overrun of the hydraulic actuator can be prevented.

According to a third aspect of the present invention, there is provided a hydraulic power unit including an engine, a hydraulic pump driven by the rotational power of the engine, and having a motor driven by electric power supplied from the outside and a hydraulic pump driven by the motor. The hydraulic pump discharge oil can be supplied to the vehicle via a hose, and when the hydraulic power unit is driven to perform work, the engine is stopped and the work is performed. A hydraulic power unit start switch for outputting a hydraulic power unit start command signal, a vehicle state detecting means for detecting a vehicle state which is abnormal if generated when the engine is driven, and which is not abnormal even when generated when the engine is stopped; An alarm buzzer activated by an alarm signal and the hydraulic power unit start switch It is characterized by comprising an alarm circuit interrupting means for interrupting the alarm signal output from the vehicle state detection means by a hydraulic power unit start command signal.

According to the third aspect of the present invention, when the engine is stopped and work is performed using the hydraulic power unit, the function of monitoring and alerting the vehicle state is also activated. Since the detection circuit for a vehicle state that is not abnormal even when the engine is stopped (for example, a decrease in engine oil pressure, a decrease in air pressure, etc.) is shut off, an alarm sound that is not an abnormal state accompanying the engine stop can be stopped.
Does not interfere with work.

According to a fourth aspect of the present invention, there is provided a hydraulic power unit including an engine, a hydraulic pump driven by the rotational power of the engine, and having a motor driven by electric power supplied from the outside and a hydraulic pump driven by the motor. The hydraulic pump discharge oil can be supplied to the vehicle via a hose, and when the hydraulic power unit is driven to perform work, the engine is stopped and the work is performed. A starter key switch for outputting an engine start command signal; and a hydraulic power unit start switch for outputting a hydraulic power unit start command signal.
Hydraulic power unit start switch (2
It is characterized by supplying power to 2).

According to the fourth aspect of the present invention, the signal for turning on the power to the hydraulic power unit is obtained from the "Acc" of the starter key switch. Therefore, the signal is supplied to the same electric circuit as that of the standard vehicle (vehicle that cannot support the hydraulic power unit). Thus, power can be supplied to each electric device of the vehicle, and work can be started by the same operation method as that of a standard vehicle driven by an engine.

According to a fifth aspect of the present invention, there is provided a hydraulic power unit including an engine, a hydraulic pump driven by the rotational power of the engine, and a motor driven by electric power supplied from the outside and a hydraulic pump driven by the motor. The hydraulic pump discharge oil can be supplied to the vehicle via a hose, and when the hydraulic power unit is driven to perform work, the engine is stopped and the work is performed. Detects the hydraulic power unit start switch that outputs the hydraulic power unit start command signal and the amount of operation of the accelerator pedal that controls the engine speed, and detects the accelerator opening that outputs to the hydraulic power unit as the hydraulic power unit motor speed command value And PT for switching whether or not the operation amount of the accelerator pedal is limited And (power take-off) switch,
A hydraulic power unit start prohibiting unit that shuts off a hydraulic power unit start command signal output from the hydraulic power unit start switch in response to a signal from the PTO switch that does not limit the operation amount of the accelerator pedal.

According to the fifth aspect of the present invention, the number of rotations of the electric motor of the hydraulic power unit can be controlled in accordance with the operation amount of the accelerator pedal. Accordingly, the crane operation can be performed by adjusting the rotation speed of the hydraulic pump of the hydraulic power unit. Further, when the PTO switch is "no limitation on the operation amount of the accelerator pedal", the hydraulic power unit cannot be driven, so the rotation speed of the hydraulic pump of the hydraulic power unit is "limited by the operation amount".
In other words, it is not possible to make the hydraulic pump larger than in the case described above, that is, it is possible to prevent overrun of the hydraulic pump. This makes it possible to prevent overload on the hydraulic equipment and prevent overrun of the hydraulic actuator.

[0018]

Embodiments of the present invention will be described below in detail with reference to the drawings. In the following, a crane truck will be described as an example of a work vehicle, but the present invention can be applied to other work vehicles such as a hydraulic shovel. As shown in FIG. 1, a crane truck 1 as a working vehicle includes a lower traveling body 2.
And a lower traveling unit 2 including a crane device 3a and a cab 3b.
And an upper revolving unit 3 that is rotatably mounted on the vehicle.
The lower traveling unit 2 includes an engine 4 serving as a power source for driving the traveling and working machines, and a plurality of hydraulic pumps 5 driven by the engine 4 via a PTO (power take-off) clutch 6.
a and a plurality of hydraulic pumps 5 b directly driven by the engine 4. The hydraulic pump 5a includes a pilot pump, a boom pump, and a winch pump, and the hydraulic pump 5b includes a steering, an outrigger, an air conditioner and an accumulate charge pump, a transmission pump, and a turning pump.

The crane truck 1 has a plurality of hoses 8
And the hydraulic power unit 7 via the wire harness 9
And can be connected. The hydraulic power unit 7 has a plurality of hydraulic pumps 7a, an electric motor 7b for driving the hydraulic pump 7a, and a control device 7c for controlling the rotation of the electric motor 7b, and is provided in a box for soundproofing, waterproofing, and dustproofing. It is stored. The hydraulic power unit 7 has a power supply cable 7d for receiving electric power from an external temporary power supply (for example, a power pole, a generator, equipment, or the like). As the plurality of hydraulic pumps 7a of the hydraulic power unit 7,
There are steering, outrigger, air conditioner and accumulate charge pump, pilot pump, turning pump, boom pump and winch pump. The oil discharged from each of these pumps 7a is supplied to the corresponding hydraulic pumps 5a and 5b on the crane truck 1 via hoses 8 respectively.

FIG. 2 is a block diagram showing the electric system of the vehicle. An electric circuit between the upper revolving unit 3 and the lower traveling unit 2 is connected via a slip ring 11. Although some circuits are directly connected to the slip ring 11, many circuits are connected to the slip ring 11 via a multiplex transmission device (hereinafter referred to as MDT). (Note that FIG. 2 shows only the circuit according to the present invention.)
An upper MDT 13 is provided on the upper revolving unit 3 side, and a lower MDT 12 is provided on the lower traveling unit 2 side.

The starter key switch 21 is "off",
It has a switching position of “Acc” and “Start”,
The signal at the “Acc” position closes a battery relay (not shown), and supplies power to each electric device of the vehicle, including a hydraulic power unit start switch 22 described later (hereinafter, the power supply at this “Acc” position is reduced to two. Next power source). Further, the signal of the "start" position closes the engine starter safety relay 18 via the relay R1 and the slip ring 11, rotates the starter, and starts the engine 4. The accelerator potentiometer 14 is provided in the vicinity of the governor lever 32 (see FIG. 3), detects the accelerator opening, which is the operation amount of the accelerator pedal 31 (see FIG. 3), by the rotation amount of the governor lever 32, and transmits the transmission controller 15 and the hydraulic power unit. 7 is output as an accelerator signal.

The hydraulic power unit start switch 22 is
A switch for turning on power to the control device 7c of the hydraulic power unit 7, which is connected to the hydraulic power unit 7 via the slip ring 11, the relay R2, and the relay R3. The hydraulic power unit drive switch 23 is a switch for driving the electric motor 7b of the hydraulic power unit 7, and is connected to the hydraulic power unit 7 via the slip ring 11.

The PTO switch 24 is connected to the PTO clutch 6
And a switch for switching the maximum engine speed set.
It is connected to a solenoid valve 19. As shown in FIG. 3, the PTO solenoid valve 19 switches the power transmission to the plurality of hydraulic pumps 5a connected to the PTO clutch 6 by switching the PTO clutch 6, and drives the engine rotation set cylinder 33. The above-mentioned switching of the presence or absence of the limitation of the rotation range of the governor lever 32 is performed. The PTO switch 24 is "off (running)",
It has a switching position of “Work 1” and “Work 2”, and when “Off (running)”, only running is possible, and when “Work 1”, work / outrigger / running is possible,
At the time of “work 2”, only work is possible. In addition, in the positions of “work 1” and “work 2”, the engine rotation is restricted, but in the “off” position, the restriction of the engine rotation is released.

The PTO solenoid valve 19 in FIG.
And the state of the engine rotation set cylinder 33 indicate a state where the PTO switch 24 is in the “OFF” position. That is, since the PTO solenoid valve 19 is in the off state, the engine rotation set cylinder 33 is in the retracted state, and the governor lever 32 can rotate to the engine full rotation position. Further, since the PTO solenoid valve 19 is in the off state, the PTO clutch 6 is in the "disengaged" state, and the plurality of hydraulic pumps 5a related to the crane device 3a do not rotate. With this, PT
When the O switch 24 is "OFF", the engine 4 is not restricted by the rotation speed and the power is not split by the plurality of hydraulic pumps 5a, so that the vehicle can travel efficiently. .

When the PTO switch 24 is switched to "operation 1" or "operation 2", the PTO solenoid valve 1
9 is switched to the ON state, and the engine rotation set cylinder 33 is extended to act as a stopper for the governor lever 32, so that the governor lever 32 can rotate only to the engine middle speed rotation position. Further, since the PTO solenoid valve 19 switches to the ON state, the PTO clutch 6 is in the "ON" state, and the plurality of hydraulic pumps 5a rotate. Accordingly, when the PTO switch 24 is in the “operation 1” and the “operation 2”, the crane operation can be performed at the engine middle speed or lower where the pump rotation required for performing the crane operation can be obtained. it can. When the crane operation is performed, the operation is performed by adjusting the engine rotation by using the operation of the accelerator pedal 31 simultaneously with the operation of the operation lever (not shown). When the PTO switch 24 is in the "work 1", traveling is possible, but the "work 2"
In the case of, only a work is possible because a circuit (not shown) is connected so that the secondary power supply to the transmission controller 15 is shut off.

The hydraulic power unit operation lamp 25 (green) is connected to the hydraulic power unit 7 via the upper MDT 13, the slip ring 11, and the lower MDT 12,
It is turned on by the operation signal output from the hydraulic power unit 7. The hydraulic power unit abnormality lamp 26 (red) indicates the upper MDT 13, the slip ring 11, and the lower MDT 12.
And is connected to the hydraulic power unit 7 via a power line, and is turned on by an abnormal signal output from the hydraulic power unit 7. In addition,
Examples of the abnormal signal include a rotation control abnormality when the rotation speed command signal based on the accelerator signal does not match the rotation detection signal of the electric motor 7b, an overheating abnormality when the electric motor 7b is overheated by the torque overload, and an electric motor 7b. Is a predetermined value (for example, a usage-restricted power 50 determined by a contract with a power company).
kW), the control power 7c of the hydraulic power unit 7 monitors the presence or absence of these abnormalities.

The engine oil pressure drop lamp 27 is
T13, slip ring 11, lower MDT 12, and relay R4 are connected to an engine oil pressure detection switch 16a (ON when oil pressure is low). The air pressure drop detection switch 16b (ON when the air pressure drops) is connected to the air pressure drop lamp 29 via the slip ring 11 and to the monitor alarm buzzer 28 via the slip ring 11 and the relay R5. Lighting and buzzer sound alert the operator of a drop in air pressure. The monitor alarm buzzer 28 is also connected to the upper MDT 13, and emits a buzzer sound also when the engine 4 stops and an abnormal signal from the hydraulic power unit 7, an engine oil pressure drop signal from the engine oil pressure detection switch 16a, or the like. The engine oil pressure detection switch 16a and the air pressure drop detection switch 16b detect a vehicle state (engine oil pressure drop, air pressure drop) which is abnormal if generated when the engine is driven and not abnormal even if generated when the engine is stopped. Means 16. The battery BT is charged by electric power from a generator driven by the engine 4 and supplies electric power to each electric device of the vehicle. The control device 7c of the hydraulic power unit 7 has a battery charger (not shown). The battery BT is charged by the battery charger while the hydraulic power unit 7 is driven, and the battery charger is connected to the secondary battery side. Supply power.

The ON signal of the hydraulic power unit start switch 22 drives the relays R1, R4, R5 to "open". The ON signal of the engine oil pressure detection switch 16a drives the relay R2 to "open". Further, the OFF signal of the PTO switch 24 drives the relay R3 to “open”.

When a crane operation is performed using the hydraulic power unit 7, the starter key switch 21 is set to "A".
After switching to the "cc" position, the hydraulic power unit start switch 22 is turned on to turn on the power to the controller 7c of the hydraulic power unit 7 (at this time, the PTO switch 24
Is "Work 1" or "Work 2"). Then, by turning on the hydraulic power unit drive switch 23, the electric motor 7b is started to drive the hydraulic pump 7a, and the discharge oil is supplied to the crane truck 1 via the hose 8. Accordingly, the crane truck 1 can perform the crane operation using the hydraulic power unit 7 with the engine stopped, and a working environment with low noise and no exhaust gas can be obtained. At this time, since a signal for turning on the power to the hydraulic power unit 7 is obtained from “Acc” of the starter key switch 21, each electric power of the vehicle is provided in the same electric circuit as that of a standard vehicle (a vehicle that cannot support the hydraulic power unit). The secondary power supply to the device becomes possible.

While the hydraulic power unit 7 is being driven, the relay R1 of the engine start circuit of the starter key switch 21 is turned on by the ON signal of the hydraulic power unit start switch 22.
, The engine 4 cannot be started. Conversely, while the engine 4 is being driven, the relay R2 of the hydraulic power unit start signal circuit from the hydraulic power unit start switch 22 is opened by the ON signal of the engine oil pressure detection switch 16a. Can not be entered. As a result, the hydraulic power unit 7 and the engine 4 cannot be driven at the same time, so that it is possible to prevent the discharge oil of the hydraulic pumps 5a and 5b from joining the discharge oil of the hydraulic pump 7a. For this reason, it is possible to prevent an overload from being applied to hydraulic devices such as hydraulic actuators and piping. Furthermore, since there is no increase in the flow rate, overrun of the hydraulic actuator can be prevented.

While the hydraulic power unit 7 is being driven, the relay R4 of the engine oil pressure lowering alarm circuit from the engine oil pressure detecting switch 16a is opened by the ON signal of the hydraulic power unit start switch 22. 27 and the buzzer 28) do not operate. Similarly, while the hydraulic power unit 7 is being driven, the relay R5 of the air pressure drop alarm circuit from the air pressure drop detection switch 16b is opened by the ON signal of the hydraulic power unit start switch 22. There is no actuation of 28. That is, when working using the hydraulic power unit 7, the monitoring function of the standard car is also operated as it is, so that the engine 4 is stopped and work is performed, the engine oil pressure does not rise, and the engine oil pressure detection switch 16a is turned on. However, since there is no replenishment of air from the compressor, the air pressure gradually decreases (the pressure drop is accelerated by the operation of the brake pedal which is unnecessary for the operation), and the air pressure drop detection switch 16b is turned on.
The alarm signal is cut off by the relays R4 and R5 to prevent the operation of the monitor alarm buzzer 28. This allows
An alarm sound that is not an abnormal state due to the stop of the engine 4 can be stopped, and does not disturb the work.

In the crane operation by the hydraulic power unit 7, the rotation speed of the hydraulic pump 7a, that is, the rotation speed of the electric motor 7b is controlled by an accelerator signal from an accelerator potentiometer 14 linked to an accelerator pedal 31. At this time, since the position of the PTO switch 24 is “Work 1” or “Work 2”, the accelerator signal from the accelerator potentiometer 14 is an accelerator signal corresponding to the engine middle speed or lower. Thus, as in the case of the crane operation driven by the engine 4, the crane operation can be performed by adjusting the rotation speed of the hydraulic pump 7 a by the combined operation of the operation lever and the accelerator pedal 31.

At this time, the PTO switch 24 is turned off.
Is switched to the position of the governor lever 32 as described above.
Can rotate to the engine full rotation position. For this reason, the accelerator signal from the potentiometer 14 can be output up to a signal corresponding to the full rotation of the engine depending on the depression amount of the accelerator pedal 31, causing the hydraulic pump 7 a to overrun. To prevent this problem, a relay R3 is provided. That is, when the PTO switch 24 is in the “OFF” position,
Since the relay R3 of the hydraulic power unit start signal circuit from the hydraulic power unit start switch 22 is opened by the OFF signal of the PTO switch 24, power cannot be supplied to the control device 7c of the hydraulic power unit 7.
For this reason, when the PTO switch 24 is in the “OFF” position, the hydraulic power unit 7 cannot be driven,
When the PTO switch 24 is switched to the “OFF” position while the hydraulic power unit 7 is being driven, the hydraulic power unit 7 stops. Thereby, the above-described hydraulic pump 7
The overrun of a can be prevented.

The hydraulic power unit start switch 2
Relays R1, R4, R5 are "opened" by the ON signal of 2
However, the same effect can be obtained by using the ON signal of the hydraulic power unit drive switch 23. The operation signal output from the hydraulic power unit 7 to the hydraulic power unit operation lamp 25 causes the relay R1,
The same effect can be obtained even if R4 and R5 are configured to be driven to "open". In the example described above, the relays R2 and R3 for disabling the hydraulic power unit 7 are provided in the hydraulic power unit start signal circuit from the hydraulic power unit start switch 22.
The same effect can be obtained by providing these relays in the hydraulic power unit drive signal circuit from No. 3.

As described above, according to the present invention, it is impossible to start the hydraulic power unit while the engine is driven, and conversely, it is impossible to start the engine while the hydraulic power unit is driven. The engine and hydraulic power unit cannot be driven simultaneously. As a result, it is possible to prevent the discharge oil from the vehicle-side hydraulic pump driven by the engine from joining with the discharge oil from the hydraulic power unit hydraulic pump, thereby preventing overload on the hydraulic equipment and adversely affecting durability. Do not give. Since an increase in the flow rate can be prevented, an increase in oil temperature due to pressure loss can be suppressed, and the heat balance is not adversely affected. Overrun of the hydraulic actuator can be prevented. Also, when working with the hydraulic power unit with the engine stopped, the function of monitoring and alerting the vehicle condition is also operating, but it is abnormal if it occurs when the engine is running, and even if it occurs when the engine is stopped, it is abnormal Since the detection circuit for the vehicle state other than the abnormal state is shut off, it is possible to stop the alarm sound which is not an abnormal state due to the engine stop and does not disturb the work. Also,
Since the signal for turning on the power to the hydraulic power unit is obtained from the “Acc” of the starter key switch, power is supplied to each electric device of the vehicle using the same electric circuit as a standard vehicle (vehicle that cannot support the hydraulic power unit). Becomes possible. Also, since the rotation speed of the electric motor of the hydraulic power unit can be controlled according to the operation amount of the accelerator pedal, the rotation of the hydraulic pump of the hydraulic power unit can be controlled by the combined operation of the operation lever and the accelerator pedal, as in the case of crane work driven by the engine. Crane operation can be performed at a controlled speed. Further, when the PTO switch is “no restriction on the operation amount of the accelerator pedal”, the hydraulic power unit cannot be driven, so that the rotation speed of the hydraulic pump of the hydraulic power unit cannot be made larger than that when “the operation amount is limited”. That is, overrun of the hydraulic pump can be prevented. This makes it possible to prevent overload on the hydraulic equipment and prevent overrun of the hydraulic actuator.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an embodiment of the present invention.

FIG. 2 is an electric system block diagram of the vehicle according to the embodiment of the present invention.

FIG. 3 is a schematic diagram illustrating the operation of a PTO solenoid valve.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Crane truck, 2 ... Lower traveling body, 3 ... Upper revolving superstructure, 4
... Engine, 5a, 5b ... Hydraulic pump, 7 ... Hydraulic power unit, 7a ... Hydraulic pump, 7b ... Electric motor, 7c ... Control device, 8 ... Hose, 14 ... Accel potentiometer,
Reference numeral 16: vehicle state detection means, 16a: engine oil pressure detection switch, 16b: air pressure drop detection switch, 21: starter key switch, 22: hydraulic power unit start switch, 23: hydraulic power unit drive switch, 24 ...
PTO switch, 28 monitor buzzer, 31 accelerator pedal, R1, R2, R2, R4, R5 relay.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) F02D 29/02 F02D 29/02 K 3H089 29/04 29/04 G F02N 11/08 F02N 11/08 X F15B 11/00 F15B 11/00 Z F term (reference) 2D015 CA01 3D037 FA23 FB14 3F204 AA04 AA09 CA05 FA02 FB16 FC03 FC08 FD07 3F205 AA06 CA03 KA10 3G093 AA04 AA10 AA15 AB05 BA06 BA24 CB14 DA02 DA06 DB00 BB25 DA06 DA00 DA14 FF01 FF10 JJ02 JJ08

Claims (5)

[Claims] An electric motor (7b) including an engine (4) and hydraulic pumps (5a, 5b) driven by the rotational power of the engine (4), and rotating by an electric power supplied from the outside, and the electric motor (7). A hydraulic pump (7a) driven by 7b) and a hydraulic power unit (7) having a hydraulic pump (7a) can supply the discharge oil of a hydraulic pump (7a) to a vehicle side via a hose (8). A starter key switch that outputs an engine start command signal in the control circuit of a hydraulic power unit type work vehicle that stops the engine (4) when performing work by driving
(21), a hydraulic power unit start switch (22) for outputting a start command signal for the hydraulic power unit (7), and a starter key switch according to the hydraulic power unit start command signal from the hydraulic power unit start switch (22).
A control circuit for a hydraulic power unit specification work vehicle, comprising: engine start prohibiting means (R1) for interrupting an engine start command signal output from (21). 2. An electric motor (7b) having an engine (4) and hydraulic pumps (5a, 5b) driven by the rotational power of the engine (4), and rotating by an electric power supplied from the outside, and the electric motor (7). A hydraulic pump (7a) driven by 7b) and a hydraulic power unit (7) having a hydraulic pump (7a) can supply the discharge oil of a hydraulic pump (7a) to a vehicle side via a hose (8). The hydraulic power unit start switch (22) that outputs a start command signal for the hydraulic power unit (7) in the control circuit of a hydraulic power unit specification work vehicle that stops the engine (4) when performing work by driving A hydraulic power unit that shuts off a hydraulic power unit start command signal output from a hydraulic power unit start switch (22) based on an engine drive signal from the engine drive detecting unit (16a). A control circuit for a working vehicle with a hydraulic power unit specification, comprising: a knit start prohibiting means (R2). 3. An electric motor (7b) having an engine (4) and hydraulic pumps (5a, 5b) driven by the rotational power of the engine (4), and rotating by an electric power supplied from the outside, and the electric motor (7). A hydraulic pump (7a) driven by 7b) and a hydraulic power unit (7) having a hydraulic pump (7a) can supply the discharge oil of a hydraulic pump (7a) to a vehicle side via a hose (8). The hydraulic power unit start switch (22) that outputs a start command signal for the hydraulic power unit (7) in the control circuit of a hydraulic power unit specification work vehicle that stops the engine (4) when performing work by driving A vehicle state detecting means (16) for detecting a vehicle state which is abnormal when the engine is driven and which is not abnormal when the engine is stopped; and an alarm buzzer which is activated by an alarm signal from the vehicle state detecting means (16). (28) and the above Vehicle condition detecting means by the hydraulic power unit start command signal from the pressure power unit start switch (22) (16)
Alarm circuit shutoff means (R
A control circuit for a working vehicle with a hydraulic power unit specification, comprising: (4, R5). 4. An electric motor (7b) including an engine (4), and hydraulic pumps (5a, 5b) driven by the rotational power of the engine (4), the electric motor (7b) being rotated by electric power supplied from the outside, and the electric motor (5). A hydraulic pump (7a) driven by 7b) and a hydraulic power unit (7) having a hydraulic pump (7a) can supply the discharge oil of a hydraulic pump (7a) to a vehicle side via a hose (8). A starter key switch that outputs an engine start command signal in the control circuit of a hydraulic power unit type work vehicle that stops the engine (4) when performing work by driving
(21) and a hydraulic power unit start switch (22) that outputs a start command signal for the hydraulic power unit (7). Power is supplied to the hydraulic power unit start switch (22) at the Acc position of the starter key switch (21). A control circuit for a working vehicle with a hydraulic power unit specification. 5. An electric motor (7b) including an engine (4), and hydraulic pumps (5a, 5b) driven by the rotational power of the engine (4), the electric motor (7b) being rotated by electric power supplied from the outside, and the electric motor (5). A hydraulic pump (7a) driven by 7b) and a hydraulic power unit (7) having a hydraulic pump (7a) can supply the discharge oil of a hydraulic pump (7a) to a vehicle side via a hose (8). The hydraulic power unit start switch (22) that outputs a start command signal for the hydraulic power unit (7) in the control circuit of a hydraulic power unit specification work vehicle that stops the engine (4) when performing work by driving The operation amount of the accelerator pedal (31) for controlling the rotation speed of the engine (4) is detected, and the electric motor (7b) of the hydraulic power unit (7) is detected.
An accelerator opening detector (14) for outputting to the hydraulic power unit (7) as a rotational speed command value of the PTO (power take-off) switch (24) for switching whether or not the operation amount of the accelerator pedal (31) is limited; A hydraulic power unit start prohibiting means (R3) for interrupting a hydraulic power unit start command signal output from the hydraulic power unit start switch (22) by a signal from the PTO switch (24) that does not limit the operation amount of the accelerator pedal (31). A control circuit for a working vehicle with a hydraulic power unit specification, comprising: