JPH1037904A - Hydraulic working vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce engine noise by driving a hydraulic pump properly even if generated horsepower is low for suppressing the rotational speed of an engine in a hydraulic working vehicle which drives a vehicle mechanically by engine power and absorbs a part of engine power taken out by a power take off device PTO so that the hydraulic pump may discharge pressure oil. SOLUTION: This vehicle is provided with a generator 8 which can conduct switching between a generating action which stores electric energy generated according a torque transmission from a hydraulic pump 2 in a storage means 10 and a motor action which transmits torque to the hydraulic pump 2 by receiving the electric energy stored in the storage means 10. With the power of a time-average value of required absorbed horsepower of the hydraulic pump 2 generated at the time of hydraulic operation, this device conducts control so that the generator 8 may be switched to the motor action if the required absorbed horsepower exceeds the time-average value and to the generating action if it does not.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic working vehicle such as an aerial working vehicle and a garbage collection vehicle in which a vehicle is driven mechanically, and more particularly to measures for reducing engine noise during hydraulic working.

[0002]

2. Description of the Related Art For example, as disclosed in Japanese Patent Application Laid-Open No. 62-156440, a variable displacement hydraulic pump directly driven by an engine is provided, and a vehicle is driven by hydraulic oil from the hydraulic pump. 2. Description of the Related Art A hydraulic excavator is known as a hydraulic traveling hydraulic working vehicle that drives and drives various working actuators.

In a conventional hydraulic working vehicle in which the vehicle is driven mechanically, as shown in FIG. 6, a power take-out device (16) for extracting a part of the power of the engine (1).
(Hereinafter, referred to as PTO [Power Take Off]), and the hydraulic pump (2) absorbs the power of the engine (1) taken out by the PTO (16) and discharges pressure oil. ing. In the same figure, (17)
Is a connecting / disconnecting device for connecting / disconnecting torque transmission between the PTO (16) and the hydraulic pump (2), and (12) is an engine (1)
The engine (1) is connected to a driving wheel (19) via a transmission (18).
(19) is driven to rotate.

[0004] The hydraulic drive device of the mechanical hydraulic working vehicle will be described in detail with reference to FIG.
The hydraulic pump (2) is, for example, a swash plate type, and controls the supply of pressure oil discharged from the hydraulic pump (2) to various working actuators (3) and (4) to control the operation thereof. A valve (5), a swash plate angle control actuator (6) for adjusting the swash plate angle of the hydraulic pump (2) to control the discharge amount (displacement volume) per rotation, and the actuator (6). ) Based on information from the control valve (5). In this hydraulic drive device, the discharge amount of the hydraulic pump (2) is controlled by the swash plate angle control actuator (6) in the hydraulic pump (2), so that various types of work actuators (3),
In (4), necessary pressure oil is supplied. In addition, the engine (1) is adjusted to change its rotation speed in accordance with the lightness of the work load. For example, the engine (1) is operated at the rated horsepower at the time of the standard load operation, and the engine (1) is operated at the maximum horsepower at the time of the heavy load operation in accordance with the work load of the actuators (3) and (4). I have.

[0005]

By the way, in the case of an aerial work vehicle used for construction of telephone lines and transmission lines, for example,
Since it is often performed at midnight when the impact of construction is small, it is necessary to minimize engine noise.

However, in the conventional hydraulic working vehicle described above, in order to cope with a change in the absorption horsepower of the hydraulic pump, FIG.
As shown in, the generated horsepower of the engine must be set to a level corresponding to the maximum value of the absorbed horsepower, or the generated horsepower of the engine must be changed according to the change in the absorbed horsepower,
For this reason, there is a problem that the engine speed increases and engine noise increases.

The present invention has been made in view of the above points, and a main object of the present invention is to drive a vehicle mechanically by the power of an engine while taking out part of the power to rotate a hydraulic pump. In a hydraulic work vehicle that is driven, by efficiently using the power extracted from the engine, it is possible to drive the hydraulic pump properly even if the engine generated horsepower is low, thereby suppressing the engine speed. To reduce engine noise.

[0008]

In order to achieve the above object, according to the present invention, an electric motor having both a power generating action and a motor action is connected to a hydraulic pump, and a power storage means is connected to the electric motor. By assisting a part of the rotational drive of the hydraulic pump, the hydraulic pump can be driven properly even if the engine generated horsepower is low.

More specifically, according to the first aspect of the present invention, as shown in FIG. 1, an engine (1) for driving a vehicle and a power take-out means (100) for extracting at least a part of the power of the engine (1). 16), a hydraulic pump (2) that absorbs the power of the engine (1) taken out by the power take-out means (16) and discharges pressure oil, and a pressure oil discharged from the hydraulic pump (2). Actuated operating part (3),
(4) is a prerequisite for a hydraulic working vehicle.

An electric motor (8) for reversibly transmitting torque to and from the hydraulic pump (2) and a power storage means (10) for transferring electric energy to and from the electric motor (8). Be prepared. The electric motor (8) has a power generation function of storing electric energy generated by receiving torque transmission from the hydraulic pump (2) in the power storage means (10), and an electric power stored in the power storage means (10). It is assumed that it can be switched to a motor operation for transmitting torque to the hydraulic pump (2) by receiving energy.

In the above configuration, the power take-out means (1
When the operation of the electric motor (8) is switched to the power generation operation in a state where the hydraulic pump (2) is rotationally driven by the power of the engine (1) taken out by 6), the electric motor (8) is driven by the hydraulic pump (2). The power is generated by receiving the torque transmission from 2). Then, the electric energy is stored in the power storage means (10). Therefore, when the hydraulic work by the hydraulic work units (3) and (4) is not performed, the power storage drive (power generation action) mode in which only the power storage is performed is performed.
In addition, when the storage and discharge are performed in parallel with the hydraulic work, the assist drive (power generation action / motor action) mode is performed. Here, when the operation of the electric motor (8) is switched to the motor operation, the electric motor (8) is operated by the electric storage means (1).
By receiving electric energy from 0) and transmitting torque to the hydraulic pump (2), a part of the rotational drive is assisted. Therefore, the amount of power taken out of the engine (1) is reduced by the amount assisted by the electric motor (8). This ensures the required absorption horsepower of the hydraulic pump (2) and the rotational speed of the engine (1). Can be kept low.
At that time, the electric energy stored in the power storage means (10) is basically stored by the power generation action of the electric motor (8) in the power storage drive mode and the assist drive mode. Power supply means (for example, a charging cord) for supplying electric energy from the outside and power supply work are basically unnecessary.

According to a second aspect of the present invention, in the first aspect of the present invention, as shown in FIG. 2, a connecting / disconnecting means (17) for connecting / disconnecting torque transmission between the power take-out means (16) and the hydraulic pump (2). And a control means (9) for controlling the operation of the connecting / disconnecting means (17) and the operation of the electric motor (8), respectively.

In the above configuration, the power take-out means (1
The torque transmission between 6) and the hydraulic pump (2) is disconnected by the operation of the disconnecting means (17). When the disconnecting / connecting means (17) is turned off, the engine (1) is operated without operating the hydraulic pump (2), and conversely, the hydraulic pump is operated without operating the engine (1). (2) can be operated.

According to a third aspect of the present invention, in the second aspect of the present invention, the control means (9) switches the connection / disconnection means (17) to the ON state during the hydraulic work and the electric motor (8).
Assist drive (power generation action / motor action) mode for switching between the power generation action and the motor action.

In the above configuration, in the assist drive (power generation action / motor action) mode during hydraulic work, the control means (9) switches the connection / disconnection means (17) to the ON state, and the electric motor (8) operates the motor action. , A part of the rotational drive of the hydraulic pump (2) is assisted by the electric motor (8), and the load on the engine (1) is reduced accordingly. On the other hand, when the electric motor (8) is switched to the power generation operation, at least a part of the power of the engine (1) absorbed by the hydraulic pump (2) is converted into electric energy and stored in the power storage means (10).

According to a fourth aspect of the present invention, in the third aspect of the present invention, as shown in FIG. 3, the engine (1) generates power smaller than the maximum required absorption horsepower of the hydraulic pump (2) during hydraulic work. (For example, idling operation). Then, the control means (9) switches the electric motor (8) to the motor operation when the required absorption horsepower of the hydraulic pump (2) exceeds the generated horsepower of the engine (1), and generates the power when it does not exceed it. It is assumed that the operation is switched to the operation.

In the above configuration, at the time of hydraulic work, the generated horsepower of the engine (1) is smaller than the maximum required absorption horsepower of the hydraulic pump (2), so the generated horsepower of the engine is the maximum required absorption horsepower of the hydraulic pump. The rotation speed of the engine (1) is lower than in the conventional case. When the required absorption horsepower of the hydraulic pump (2) exceeds the generated horsepower of the engine (1), the shortage is determined by the electric motor (8).
, The required absorption horsepower of the hydraulic pump (2) is satisfied, and the hydraulic working unit (3,
4) is properly driven. On the other hand, when the required absorption horsepower does not exceed the generated horsepower of the engine (1), the electric motor (8)
Is switched to a power generation operation, and the surplus of the generated horsepower is converted into electric energy and stored in the power storage means (10).

According to a fifth aspect of the present invention, in the fourth aspect of the present invention, the engine (1) is configured to generate a power having a time average of a required absorption horsepower of the hydraulic pump (2). I do. Then, the control means (9) switches the electric motor (8) to the motor operation when the required absorption horsepower of the hydraulic pump (2) exceeds the time average value, and switches to the power generation operation when the required absorption horsepower does not exceed the time average value. It is assumed to be configured as

In the above configuration, during a hydraulic operation, the engine (1) generates power having a time average value of the required absorption horsepower of the hydraulic pump (2). Then, when the required absorption horsepower of the hydraulic pump (2) exceeds the time average value, the shortage is assisted by the motor action of the electric motor (8). On the other hand, when the required absorption horsepower does not exceed the time average,
Electric energy is stored in the power storage means (10) by the power generation action of the electric motor (8). Therefore, the power of the engine (1) is used efficiently.

According to a sixth aspect of the present invention, in the second aspect of the present invention, the control means (9) switches the disconnecting / connecting means (17) to the off state during the hydraulic work and the electric motor (8).
Has a discharge drive (motor action) mode for switching to a motor action.

In the above configuration, during the hydraulic operation, the disconnecting / connecting means (17) is switched off by the control means (9) and the electric motor (8) is switched to the motor function. As a result, the hydraulic pump (2) is rotationally driven only by the electric motor (8), so that the engine (1)
Can be stopped so that no engine noise is generated.

According to a seventh aspect of the present invention, in the second aspect of the present invention, the control means (9) switches the connection / disconnection means (17) to an ON state when the vehicle is running, and controls the electric motor (8).
Assist drive (power generation action / motor action) mode for switching between the power generation action and the motor action.

In the above configuration, in the assist drive (power generation / motor operation) mode when the vehicle is traveling, the control means (9) switches the connection / disconnection means (17) to the ON state and the electric motor (8) operates the motor. , The power of the electric motor (8) is transmitted to the engine (1) via the hydraulic pump (2), the connecting / disconnecting means (17) and the power take-out means (16). The driving of the vehicle according to 1) is assisted by the electric motor (8). On the other hand, when the electric motor (8) is switched to the power generation operation, part of the power of the engine (1) taken out by the power take-out means (16) is converted into electric energy and stored in the power storage means (10).

According to an eighth aspect of the present invention, in the first to seventh aspects, the electric motor (8) is located at an outer peripheral position surrounding the pump shaft (21) of the hydraulic pump (2) as shown in FIG. It is assumed that they are integrally mounted on the hydraulic pump (2) in a state where they are arranged.

Generally, the electric motor (8) is connected to the hydraulic pump (2)
In order to transfer torque between the electric motor (8) and the hydraulic pump (2), the pump shaft (21) of the hydraulic pump (2) and the rotating shaft of the electric motor (8) are usually combined. Must be arranged in series, and the hydraulic drive device must be relatively long in the direction of the pump shaft (21) of the hydraulic pump (2) and must be increased in size. ) Is disposed on the outer peripheral side of the hydraulic pump (2) and is integrally assembled with the hydraulic pump (2).
1) The length in the direction can be reduced, and the size can be reduced.

According to a ninth aspect of the present invention, in the above-mentioned eighth aspect, the hydraulic pump (2) includes a cylinder block (22) rotating integrally with the pump shaft (21), and a periphery of the cylinder block (22). And a housing (25) that covers the cylinder block (22), the electric motor (8) includes a rotor (81) rotatably mounted at a position on the outer peripheral surface side of the cylinder block (22), and the rotor (81). And a stator (82) attached to the inner peripheral surface side of the housing (25) so as to face radially around the pump shaft (21).

In the above configuration, the rotor (81) of the electric motor (8) is connected to the cylinder block (2) of the hydraulic pump (2).
Since the stator (82) of the electric motor (8) is attached to the outer peripheral surface of the housing (25) of the hydraulic pump (2), the electric motor (8) is attached integrally to the outer peripheral surface of the electric motor (2). (8) itself is integrally disposed in the housing (25) of the hydraulic pump (2).
Therefore, the heat generated by the operation of the electric motor (8) is cooled by the hydraulic oil of the hydraulic pump (2), and the temperature rise is suppressed.

[0028]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a drive system of a hydraulic working vehicle according to an embodiment of the present invention. The drive system includes an engine (1) such as a diesel engine for driving a vehicle and a power take-out device (16) (hereinafter referred to as a PTO) as a power take-out means for taking out at least a part of the power of the engine (1).
And a hydraulic pump (2) that absorbs the power of the engine (1) extracted by the PTO (16) and discharges pressure oil. The engine (1) is shown in FIG.
As shown in the hydraulic drive device, the drive wheels (19) and (19) of the vehicle are driven to rotate via a transmission (18), while the hydraulic pump (2) discharges the drive wheels. The working actuators (3) and (4) as operating parts are driven by the pressure oil.

The hydraulic drive device for driving the actuators (3) and (4) will be described. The hydraulic pump (2) is a swash plate type variable displacement type.
The swash plate angle is changed by the tilt actuator (6). The operation of the tilt actuator (6) is controlled by a control valve (7), whereby the flow rate of the discharge oil from the hydraulic pump (2) is controlled. On the other hand, the actuators (3) and (4) are composed of a hydraulic motor, a hydraulic cylinder, and the like, and the direction and amount of pressure oil supply to these are controlled by a control valve (5).

In this embodiment, in the above-mentioned hydraulic drive device, an electric motor (8) for reversibly transmitting torque to and from the hydraulic pump (2) and electric energy between the electric motor (8). There is provided a power storage means (10) such as a battery for delivery. In other words, the electric motor (8) receives the torque transmitted from the hydraulic pump (2) and stores the electric energy generated by the electric power storage means (10) in the power storage means (10), and the electric energy stored in the power storage means (10). The operation can be switched to a motor operation for transmitting torque to the hydraulic pump (2). A connection / disconnection device (17) is provided between the PTO (16) and the hydraulic pump (2) as connection / disconnection means including an electromagnetic clutch for connecting / disconnecting torque transmission therebetween. And
Each operation of the disconnecting device (17) and the operation of the electric motor (8) are controlled by a controller (9) as control means.

Here, the basic control mode of the controller (9) during the hydraulic work on the disconnecting / connecting device (17) and the electric motor (8) will be described.
Has an assist drive (power generation action / motor action) mode in which the connection / disconnection device (17) is switched on and the power generation action and motor action of the electric motor (8) are switched. In the basic control mode when the vehicle is running, the disconnecting device (1)
7) is switched to the off state.

More specifically, the engine (1) is controlled (for example, idling operation) so as to generate power smaller than the maximum required absorption horsepower of the hydraulic pump (2). The electric motor (8) is switched to the motor operation when the required absorption horsepower of the hydraulic pump (2) exceeds the generated horsepower of the engine (1), and when it does not exceed the required absorption horsepower (specifically, the required absorption horsepower). Is less than the generated horsepower).

More specifically, as shown in FIG. 3, the engine (1) is controlled so as to generate power having a time average value of required absorption horsepower of the hydraulic pump (2). And
The electric motor (8) is switched to the motor operation when the required absorption horsepower of the hydraulic pump (2) exceeds the time average value, whereas when the required absorption horsepower does not exceed the time average value (specifically, when the required absorption horsepower is less than the time average value). At some point), the operation is switched to the power generation operation. The speed of the engine (1) is controlled by a governor (12). The governor (12) receives a rotation speed control signal from a controller (9) and controls the rotation speed of the engine (1). Has been made to change.

The configuration of the hydraulic pump (2) and the electric motor (8) will be described in detail with reference to FIG. The hydraulic pump (2) is configured as a motor-integrated hydraulic pump (13) in which an electric motor (8) is integrally mounted. That is, the hydraulic pump (2)
A pump shaft (21) connected to the O (16) via a disconnecting / connecting device (17); and a cylinder block (spline-fitted to the pump shaft (21) and rotated integrally with the pump shaft (21)). 22) and the cylinder block (22)
And a piston row (23) composed of a plurality of pistons arranged in a circumferential direction inside the piston row (2).
3) A swash plate (24) for controlling the stroke amount of (3) and a housing (25) including the swash plate and enclosing them to form a closed structure. On the other hand, the electric motor (8) includes a rotor (81) and a stator (82). The rotor (81) is pressed into the outer peripheral surface of the cylinder block (22) and is integrated with the cylinder block (22). The stator (82) is disposed so as to be rotated by the rotor (81).
And pressed into the inner peripheral surface of the housing (25) so as to be radially opposed to each other and fixed in a non-rotating state. That is, the electric motor (8) is disposed at a position on the outer peripheral side of the cylinder block (22) centering on the pump shaft (21), and is integrally encased by the housing (25).

In the hydraulic pump (2), the swash plate (24) is tilted by a tilt actuator (6) disposed in the housing (25). In response to (24), the cylinder block (22) is rotated and the piston train (23) is reciprocated to supply an amount of pressure oil corresponding to the swash plate angle to the control valve (5). ing.
That is, the swash plate (24) is switched by the control valve (7) according to the work load of each of the work actuators (3) and (4) based on the operation amount of an operation lever (not shown) by the operator of the hydraulic work vehicle. The tilting is controlled in accordance with the operation amount of the tilting actuator (6), and the piston train (2) is controlled in accordance with the change of the swash plate angle.
The stroke amount of 3) is changed so that a predetermined amount of pressure oil is discharged.

Specifically, the hydraulic pump (2) is controlled based on an absorption torque diagram shown in FIG. In other words, the maximum discharge amount (maximum displacement) (line segment AB) determined by the hydraulic pump (2) itself, the maximum allowable pressure (line segment CD) determined by the entire system of the hydraulic drive device, and the engine (1) itself. The operation is performed in a limited region surrounded by the maximum absorption torque (hyperbolic BC) of the hydraulic pump (2). The absorption torque of the hydraulic pump (2) is a torque required for the hydraulic pump (2) to operate the various working actuators (3) and (4), and is a torque of the engine (1). This is the torque absorbed from the output torque. This absorption torque is equivalent to a value obtained by multiplying the discharge pressure of the hydraulic pump (2) by a discharge amount per one turn (displacement volume). It becomes absorption horsepower.

On the other hand, in the electric motor (8), the frequency of the current flowing through the stator (82) is converted by the inverter circuit built in the controller (9) during the power generation operation, and the motor (8) is moved from the stator (82) to the rotor ( The magnetic force acting on 81) acts on the rotor (81), which is driven to rotate at a constant speed by the engine (1), on the side that brakes the rotation of the rotor (81). Of the horsepower transmitted to the hydraulic pump (2),
Excess horsepower corresponding to the difference from the required absorption horsepower of the hydraulic pump (2) is absorbed by the electric motor (8) to generate electric power, and the generated electric energy is stored in the electric storage means (10). On the other hand, in the motor operation, the above frequency conversion converts the stator (82) to the rotor (81).
The magnetic force acting on the rotor (8)
In contrast to 1), the controller (9) controls the electric energy flowing from the power storage means (10) to the stator (82) so as to act on the side that promotes the rotation of the rotor (81). The required horsepower, which is greater than the required absorption horsepower over the time average, is applied to the hydraulic pump (2). That is, in the motor operation, the electric motor (8) plays a role as a normal electric motor.

Next, a specific operation of the hydraulic working vehicle in the assist drive (power generation action / motor action) mode will be described.

First, when the vehicle is running, the disconnecting / connecting device (17)
Is switched to the OFF state, the power of the engine (1) is not consumed for the rotational drive of the hydraulic pump (2), and the load on the engine (1) is reduced accordingly. On the other hand, at the time of hydraulic work, the disconnection device (17) is switched to the ON state and the electric motor (8) is switched to the motor operation, so that a part of the rotational drive of the hydraulic pump (2) is assisted by the electric motor (8). Therefore, the load on the engine (1) is also reduced in this case.

Further, at the time of the hydraulic operation, the generated horsepower of the engine (1) is smaller than the maximum required absorption horsepower of the hydraulic pump (2), so that the generated horsepower of the engine is the maximum required absorption horsepower of the hydraulic pump. The rotation speed of the engine (1) is lower than in the case. When the required absorption horsepower of the hydraulic pump (2) exceeds the generated horsepower of the engine (1), the shortage is assisted by the motor action of the electric motor (8). The absorbed horsepower is satisfied, and the hydraulic working units (3, 4) are properly driven. On the other hand, when the required absorption horsepower does not exceed the generated horsepower of the engine (1), the electric motor (8) is switched to the power generation operation, and the generated horsepower exceeding the required absorption horsepower is converted into electric energy and stored in the power storage means (10). ).

Further, during the above-mentioned hydraulic operation, the engine (1) generates power of a time average value of the required absorption horsepower of the hydraulic pump (2), and the required absorption horsepower of the hydraulic pump (2) reduces the time average value. When it exceeds, the shortage is assisted by the motor action of the electric motor (8). On the other hand, when the required absorption horsepower does not exceed the time average value, electric energy is stored in the power storage means (10) by the power generation action of the electric motor (8). Therefore, the power of the engine (1) is used efficiently.

Next, other control modes of the controller (9) for the connection / disconnection device (17) and the electric motor (8) will be described.
Is switched on, and the electric motor (8) is switched to a power generation operation.
In addition, there is a discharge drive (motor action) mode in which the disconnecting / connecting device (17) is switched to an off state during hydraulic work and the electric motor (8) is switched to a motor action. That is, this is a control mode in which the hydraulic pump (2) is driven only by the electric motor (8) without using the power of the engine (1) at all.
Further, there is an assist drive (power generation action / motor action) mode when the vehicle is running. This means that the connection / disconnection device (17) is switched to the ON state when the vehicle is running and the motor (8)
By switching between the power generation function and the motor function, the motor (8) assists a part of the driving of the vehicle by the engine (1).

Therefore, according to the present embodiment, the engine (1) for driving the vehicle, the PTO (16) for extracting at least a part of the power of the engine (1), and the PTO (16) extracted by the PTO (16) A hydraulic pump that absorbs the power of the engine (1) and discharges the hydraulic oil, and actuators (3) and (4) that are driven by the hydraulic oil discharged from the hydraulic pump (2). In the hydraulic working vehicle, an electric motor (8) for reversibly transmitting torque to and from the hydraulic pump (2), and a power storage means (10) for transferring electric energy to and from the electric motor (8).
The electric motor (8) receives electric power generated by receiving the torque from the hydraulic pump (2) and stores the electric energy in the electric storage means (10), and stores the electric energy in the electric storage means (10). Since it can be switched to a motor function for transmitting torque to the hydraulic pump (2) by receiving the received electric energy, a part of the rotational drive of the hydraulic pump (2) is changed to an electric motor (8). As a result, the power taken out of the engine (1) can be reduced by the amount assisted by the engine, so that the rotational speed of the engine (1) can be reduced while securing the required absorption horsepower of the hydraulic pump (2). Thus, engine noise can be reduced. Furthermore, it is possible to use the engine (1) with high efficiency and to increase the power of the entire hydraulic drive device, and to contribute to a reduction in fuel consumption and an exhaust gas amount.

A connection / disconnection device (17) for connecting / disconnecting torque transmission between the PTO (16) and the hydraulic pump (2);
A controller (9) for controlling the operation of the connecting / disconnecting device (17) and the operation of the electric motor (8) is provided.
Various operation modes can be realized by combining the on / off state of the motor and the power generation function and the motor function of the electric motor (8).

That is, as the basic control mode at the time of the hydraulic work by the controller (9), the connection / disconnection device (1)
7) is switched to the ON state, and the assist drive mode for switching the power generation operation and the motor operation of the electric motor (8) is set, so that the load on the engine (1) during hydraulic work can be reduced.

At this time, the engine (1) is set so as to generate power smaller than the maximum required absorption horsepower of the hydraulic pump (2), and the required absorption horsepower of the hydraulic pump (2) is controlled by the engine ( Since the generator (8) is switched to the motor operation when the generated horsepower of (1) is exceeded, in the conventional case where the generated horsepower of the engine (1) is the maximum required absorption horsepower of the hydraulic pump (2). In comparison, the engine noise can be reduced by lowering the rotation speed of the engine (1), while the remaining horsepower generated is stored as electric energy when the electric motor (8) is switched to the motor operation. Can be.

Further, the engine (1) for the hydraulic operation
The power of the hydraulic pump (2) needs to be generated at the time average of the required absorption horsepower, and when the required absorption horsepower of the hydraulic pump (2) exceeds the time average, the generator (8) is switched to the motor operation while the operation is switched to the power generation operation when the power is not exceeded, so that the power of the engine (1) can be used efficiently.

In the discharge drive (motor operation) mode of the controller (9), the disconnecting / connecting device (17) can be switched off and the electric motor (8) can be switched to the power generation operation. In this case, the hydraulic pump (2) can be driven to rotate only by the electric motor (8). As a result, the operation of the engine (1) can be stopped so that no engine noise is generated. it can.

Further, in the assist drive (power generation action / motor action) mode of the controller (9) when the vehicle is running, the connection / disconnection device (17) is switched to the ON state and the electric motor (8) is switched to the motor action. In this case, the power of the electric motor (8) can be transmitted to the engine (1), and the driving of the vehicle by the engine (1) can be assisted by the electric motor (8). .

In addition, since the hydraulic pump (2) has an integral structure with the electric motor (8) as described above, the length of the hydraulic pump (2), particularly in the direction of the pump shaft (21), can be reduced by adding the electric motor (8). In addition, it is possible to reduce the size of the entire hydraulic drive device, and to prevent overheating of the electric motor (8) itself by oil cooling by oil on the hydraulic pump (2) side, thereby maintaining the performance of the electric motor (8) and improving durability. Can be achieved.

In the above embodiment, the induction motor (8) serving also as an induction generator is shown as the motor (8). However, the invention is not limited to this, and a synchronous motor such as a brushless DC motor may be used.

Further, in the above embodiment, the power storage means (10) is constituted by a battery, but may be constituted by a capacitor or the like.

In the above embodiment, the disconnecting device (1
Regarding the control mode of the controller (9) for the operation of 7) and the operation of the electric motor (8), a power storage drive (power generation function) mode during vehicle running, and an assist drive (power generation action / motor action) mode during vehicle running and hydraulic work. Although only the discharge drive (motor action) mode during hydraulic work is described,
An arbitrary control mode can be set by appropriately combining the on / off state of the disconnecting / connecting device (17) and the power generation operation and the motor operation of the electric motor.

Further, in the hydraulic working vehicle according to the present invention, the motive power of the engine (1) is mechanically transmitted to the drive wheels to drive the vehicle while traveling, while the hydraulic oil supplied from the hydraulic pump (2) is used to drive the working section. The present invention can be applied to any driving device.

[0056]

As described above, according to the first aspect of the present invention, the engine for driving the vehicle, the power take-out means for taking out at least a part of the power of the engine, and the power taken out by the power take-out means. Torque transmission between the hydraulic pump and a hydraulic pump having a hydraulic pump that absorbs the power of the engine and discharges hydraulic oil, and an operating unit driven by the hydraulic oil discharged from the hydraulic pump. And a power storage means for transferring electric energy between the electric motor and the electric motor, and the electric energy generated by receiving the torque transmitted from the hydraulic pump to the power storage means. It is configured to be switchable between a power generation function to be stored and a motor function to transmit torque to the hydraulic pump by receiving electric energy stored in the power storage means. Since the, it is possible to reduce the occurrence horsepower amount corresponding engine the electric motor assists. Therefore, the engine speed can be kept low while securing the required absorption horsepower of the hydraulic pump, and as a result, engine noise can be reduced. Furthermore, it is possible to use the engine with high efficiency and to increase the power of the entire hydraulic drive device, and to contribute to a reduction in fuel consumption and a reduction in exhaust gas amount.

According to the second aspect of the present invention, there is provided a connecting / disconnecting means for connecting / disconnecting torque transmission between the power take-out means and the hydraulic pump, and a control means for controlling the operation of the connecting / disconnecting means and the operation of the electric motor, respectively. With this configuration, it is possible to realize various operation modes by combining the on / off state of the connecting / disconnecting means, the power generation function of the electric motor, and the motor function during traveling of the vehicle or hydraulic work.

According to the third aspect of the present invention, the control means has an assist drive (power generation action / motor action) mode in which the connection / disconnection means is turned on during hydraulic work and the power generation action and the motor action of the electric motor are switched. As a result, the load on the engine during hydraulic work can be reduced.

According to the fourth aspect of the present invention, the engine is configured to generate power smaller than the maximum required absorption horsepower of the hydraulic pump during a hydraulic operation, and the control means is controlled by the hydraulic pump. When the absorbed horsepower exceeds the engine-generated horsepower, the motor is switched to the motor function, and when it is not exceeded, the motor is switched to the power-generating function. Compared to the conventional case of horsepower, engine noise can be reduced by lowering the engine speed, while the remaining horsepower generated is stored as electric energy when the electric motor is switched to motor operation. I can put it.

According to the fifth aspect of the present invention, the engine at the time of the hydraulic operation is configured to generate a power having a time average value of the required absorption horsepower of the hydraulic pump, and the control means is provided with the hydraulic pump. When the required absorption horsepower exceeds the time average value, the motor is switched to the motor operation, and when the required absorption horsepower is not exceeded, the motor is switched to the power generation operation, so that the power of the engine can be used efficiently. .

According to the sixth aspect of the present invention, the control means has a discharge drive (motor action) mode in which the connection / disconnection means is turned off and the electric motor is switched to the motor action during hydraulic work. The pump can be driven to rotate only by the electric motor,
As a result, the operation of the engine can be stopped so that no engine noise is generated.

According to the seventh aspect of the present invention, the control means has an assist drive (power generation action / motor action) mode in which the connection / disconnection means is turned on when the vehicle is running and the power generation action and the motor action of the electric motor are switched. As a result, the power of the electric motor can be transmitted to the engine via the hydraulic pump, the connecting / disconnecting means, and the power take-out means, and the driving of the vehicle by the engine can be assisted by the electric motor.

According to the eighth aspect of the present invention, the electric motor is
Since it is arranged integrally with the hydraulic pump in a state where it is arranged at an outer peripheral side position surrounding the pump shaft of the hydraulic pump,
In particular, the length of the hydraulic drive device in the axial direction of the pump can be reduced, and the size can be reduced.

According to the ninth aspect of the present invention, when the hydraulic pump has a cylinder block that rotates integrally with a pump shaft and a housing that covers the periphery of the cylinder block, the electric motor is connected to the cylinder block. A rotor attached integrally with the rotor on the outer peripheral surface side of the block and a stator attached on the inner peripheral surface side of the housing so as to face the rotor in the radial direction about the pump shaft. With this configuration, the heat generated by the operation of the electric motor can be cooled by the hydraulic oil of the hydraulic pump to suppress the temperature rise.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a hydraulic work vehicle according to the present invention.

FIG. 2 is a circuit diagram showing a hydraulic drive device of the hydraulic work vehicle.

FIG. 3 is a characteristic diagram showing a relationship between an engine generated horsepower and a hydraulic absorption horsepower.

FIG. 4 is a longitudinal sectional view showing a state where the electric motor is integrally assembled with the hydraulic pump.

FIG. 5 is a characteristic diagram showing a relationship between a discharge amount of a hydraulic pump and a discharge pressure.

FIG. 6 is a diagram corresponding to FIG. 1 showing a configuration of a conventional hydraulic working vehicle.

FIG. 7 is a diagram corresponding to FIG. 2 showing a hydraulic drive device of the hydraulic work vehicle.

FIG. 8 is a diagram corresponding to FIG. 3, showing a relationship between an engine generated horsepower and a hydraulic absorption horsepower.

[Explanation of symbols]

 (1) Engine (2) Hydraulic pump (3), (4) Working actuator (operating part) (8) Electric motor (9) Controller (control means) (10) Power storage means (16) Power take-out device (power take-out means) (17) Disconnection / disconnection device (disconnection means) (21) Pump shaft (22) Cylinder block (25) Housing (81) Rotor (82) Stator

Claims (9)

[Claims] An engine for driving a vehicle (1),
A power take-out means (16) for taking out at least a part of the power of the engine (1); and a hydraulic pump () for absorbing the power of the engine (1) taken out by the power take-out means (16) and discharging the pressure oil. 2) and an operating unit (3), (4) driven by pressure oil discharged from the hydraulic pump (2), wherein torque is transmitted between the hydraulic pump (2) and the hydraulic pump (2). And a power storage means (10) for transferring electric energy between the electric motor (8) and the electric motor (8). A power generating action of storing electric energy generated by receiving the torque transmission in the power storage means (10); and a hydraulic pump (2) receiving the electric energy stored in the power storage means (10).
A hydraulic work vehicle characterized in that it can be switched to a motor function for transmitting torque to the hydraulic work vehicle. 2. The hydraulic work vehicle according to claim 1, wherein said disconnection means (17) disconnects and connects torque transmission between the power take-out means (16) and the hydraulic pump (2). A hydraulic working vehicle comprising: a control means (9) for controlling operation and operation of an electric motor (8), respectively. 3. The hydraulic work vehicle according to claim 2, wherein the control means (9) switches the connection / disconnection means (17) to an ON state during the hydraulic work and switches between the power generation function and the motor function of the electric motor (8). A hydraulic working vehicle having a drive mode. 4. The hydraulic working vehicle according to claim 3, wherein the engine (1) is configured to generate power smaller than the maximum required absorption horsepower of the hydraulic pump (2) during hydraulic work, and the control means (9). ) Is configured to switch the electric motor (8) to the motor function when the required absorption horsepower of the hydraulic pump (2) exceeds the generated horsepower of the engine (1), and to switch to the power generation function when the required absorption horsepower does not exceed the generated horsepower. A hydraulic working vehicle. 5. The hydraulic working vehicle according to claim 4, wherein the engine (1) is configured to generate a power having a time average of a required absorption horsepower of the hydraulic pump (2), and the control means (9) includes: When the required absorption horsepower of the hydraulic pump (2) exceeds the time average value, the electric motor (8) is switched to the motor operation, and when it does not exceed the average power, the operation is switched to the power generation operation. Hydraulic work vehicle. 6. The hydraulic working vehicle according to claim 2, wherein the control means (9) switches a discharge drive mode for switching the connection / disconnection means (17) to an off state and for switching the electric motor (8) to a motor operation during the hydraulic work. A hydraulic work vehicle having: 7. The hydraulic work vehicle according to claim 2, wherein the control means (9) switches the connection / disconnection means (17) to an ON state during traveling of the vehicle and assists switching between a power generation function and a motor function of the electric motor (8). A hydraulic working vehicle having a drive mode. 8. The hydraulic working vehicle according to claim 1, wherein the electric motor (8) is a pump shaft (21) of the hydraulic pump (2).
A hydraulic working vehicle, wherein the hydraulic working vehicle is integrally mounted on the hydraulic pump (2) in a state of being disposed at an outer peripheral side position surrounding the hydraulic pump (2). 9. The hydraulic working vehicle according to claim 8, wherein the hydraulic pump (2) includes a cylinder block (22) that rotates integrally with the pump shaft (21), and a housing that covers a periphery of the cylinder block (22). A motor (8), the rotor (81) being integrally mounted on the outer peripheral surface side of the cylinder block (22) so as to rotate integrally therewith;
And the housing (2) so as to face the rotor (81) radially around the pump shaft (21).
The stator (82) attached to the position on the inner peripheral surface side of 5).
A hydraulic working vehicle comprising: