JPH10103112A - Hydraulic driving gear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain improvement of absorbing torque of an oil hydraulic pump, reduction of an engine load, improvement of a fuel consumption factor and lower noise generation, concurrently while attaining miniaturization of the oil hydraulic pump and an engine, and attain also regeneration of rotary kinetic energy from a turn unit of large inertia. SOLUTION: By an engine 1, an oil hydraulic pump 2 is driven, by pressure oil from the oil hydraulic pump, each work actuator (3a, 3b) is driven. An electric motor 8 concurrently serving as a generator is additionally provided in the oil hydraulic pump, by switching control of a controller 9, generating operation and assist operation are performed by the electric motor. A turn pump motor 4, driving a turn unit 32 with motor operation by pressure oil supplied from an accumulator 12, is provided, by switching control of a turn controller 17, at braking time of a turn system, by pump operation, rotary kinetic energy is regenerated. A second electric motor 16 concurrently serving as a generator is additionally provided in the turn pump motor, by switching control of the turn controller, generating operation and assist operation are performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic drive device used in construction machines such as hydraulic excavators and wheel loaders, and hydraulic working machines such as forklifts and garbage trucks.

[0002]

2. Description of the Related Art Heretofore, as this type of hydraulic drive, an engine and a variable displacement hydraulic pump driven by the engine have been provided, and the hydraulic oil from the hydraulic pump drives the lower traveling body and various operating parts. Is known (for example, refer to Japanese Patent Application Laid-Open No. 62-156440). As shown in FIG. 1, an example of a hydraulic excavator generally includes an engine (1), a hydraulic pump (2) rotationally driven by the engine (1), and a hydraulic pump (2). ), A control valve (5) for controlling the supply of hydraulic oil to various working actuators (3, 4) such as a turning hydraulic motor and a bucket operating cylinder, and controlling the operation thereof, and the hydraulic pump (2). ) A swash plate angle control actuator (6) for adjusting the swash plate angle and controlling the displacement.
A control valve (7) for controlling the actuator (6) based on information from the control valve (5) is provided. In this hydraulic drive device, the hydraulic pump (2) controls the displacement of the hydraulic oil of the hydraulic pump (2) by the swash plate angle control actuator (6), thereby controlling the various working actuators (3, 3).
The necessary pressure oil is supplied in 4).
The engine (1) is adapted to change and adjust the number of revolutions in accordance with the displacement control by the hydraulic pump (2). That is, as shown in FIG. 2, the hydraulic drive device described above shows an absorption torque diagram of the hydraulic pump (2).
In orthogonal coordinates defined by the horizontal axis indicating the discharge pressure of the hydraulic pump (2) and the vertical axis indicating the displacement, the maximum displacement (line A) determined by the hydraulic pump (2) itself.
B), the maximum allowable pressure (line segment CD) determined by the entire hydraulic drive system, and the maximum absorption torque (hyperbolic BC) of the hydraulic pump (2) determined by the engine (1) itself.
The operation is performed in the limited area surrounded by The absorption torque of the hydraulic pump (2) is
Hydraulic pump (2) is used for various work actuators (3,
This is the torque required to operate 4), and is the torque absorbed from the output torque of the engine (1). This absorption torque corresponds to the discharge pressure of the hydraulic pump (2) multiplied by the displacement per rotation. The product of the absorption torque and the rotation speed is the absorption horsepower of the hydraulic pump (2).

[0003] In the hydraulic drive system including the engine (1) and the hydraulic pump (2), depending on the lightness of the work load applied to the various work actuators (3, 4), a standard load work is performed. The engine (1) is operated at the rated horsepower, and the engine (1) is operated at the maximum horsepower during heavy load work. The state of the engine (1) during the standard load operation and the heavy load operation will be described below.

The absorption torque of the hydraulic pump (2) during the standard load operation is, for example, in a range indicated by Ty1 to Ty2 in FIG. 2, and the required absorption torque of the hydraulic pump (2) during the heavy load operation is shown in FIG. Assuming that Ty3 is in the region beyond the hyperbola BC, the engine (1) rotational speed and the shaft torque, shaft output, and fuel consumption rate at that rotational speed are the performance curves of the engine (1) in FIG. It becomes as shown in. That is, during the standard load operation, the generated shaft torque becomes Tg1 to Tg2, the generated shaft output (generated horsepower) becomes Pe1 to Pe2, and the fuel consumption rate becomes ge1 to ge2, respectively, corresponding to the absorption torques Ty1 to Ty2. In conjunction with this, the engine (1) is operated at the rated speeds Ne1 to Ne2 by the governor controlling the engine (1). FIG. 4 shows this in a time chart. That is, in normal work, the engine (1) generates a shaft torque in the range of Tg1 to Tg2, and the engine speed is controlled in the range of the rated speed Ne1 to Ne2.

[0005] When heavy load work becomes necessary in a part of such standard load work, the amount of work of various work actuators (3, 4) increases, and hydraulic pressure is applied to these actuators (3, 4). It is necessary to supply pressure oil at an absorption torque Ty3 exceeding the maximum absorption torque line (hyperbolic BC) of the pump (2). In this case, the operation of the engine (1) is changed to the maximum horsepower operation in which the engine (1) is operated at the maximum rotation speed Np1 to Np2 by the governor in conjunction with the operation of the throttle lever or the like by the operator, whereby the load on the hydraulic pump (2) is changed. Is in the above-mentioned absorption torque range of Ty1 to Ty2, and the load of the engine (1) is correspondingly adjusted so that the generated shaft torque is T
g1 to Tg2, generated horsepower to Pp1 to Pp2, and fuel consumption rate to g
p1 to gp2. FIG. 5 is a time chart showing the heavy load operation. In other words, at the time of heavy load work, the engine (1) is put into the maximum horsepower operating state and the number of revolutions is increased, so that the hydraulic pump (2) is driven in the above-mentioned limited area (ABCD) while the limited area (ABCD) is being driven. The hydraulic oil necessary for heavy-load work can be supplied to the various work actuators (3, 4) by the absorption torque inside.

[0006]

However, in the above-mentioned conventional hydraulic drive system comprising a combination of the engine (1) and the hydraulic pump (2), the driving source mainly for driving the hydraulic pump (2) is the engine (1). ) Causes the following inconveniences.

First, the maximum absorption torque of the hydraulic pump (2) is limited by the maximum generated torque of the engine (1), and the maximum absorption torque of the hydraulic pump (2) is increased to increase the capacity of the hydraulic drive device. It is necessary to change the engine (1) to one having a large torque in order to improve the torque. In this case, when the engine (1) is changed to one having a large torque, not only the size and cost of the hydraulic drive device are increased, but also,
Inconveniences such as deterioration of fuel consumption rate, increase of noise, increase of exhaust gas, etc. are also caused.

Second, since the rated horsepower operation during the standard load operation and the maximum horsepower operation during the heavy load operation are performed by the same engine (1), the fuel consumption rate deteriorates during the heavy load operation.
Inconveniences such as an increase in engine noise and an increase in exhaust gas are caused.

Third, even during a standard load operation, the engine (1) is controlled according to the required absorption torque of the hydraulic pump (2).
Is changed in the range of Ne1 to Ne2, the fuel consumption rate fluctuates accordingly, and the fuel consumption rate deteriorates. Further, the generated shaft torque of the engine (1) is increased or decreased according to the required absorption torque of the hydraulic pump (2), which is not preferable from the viewpoint of effectively utilizing the capability of the engine (1). That is, even if the engine (1) has a torque capacity of, for example, 100 that the hydraulic pump (2) can apply to the hydraulic pump (2), the hydraulic pump (2) is
Not all of 00 are used, but only a part of them, which is not preferable in terms of efficiency.

Therefore, in order to solve the above-mentioned inconvenience,
It is conceivable to provide an electric motor that reversibly transmits torque to and from the hydraulic pump so that the engine can maintain a constant operation at a fixed rotation speed such as a rated rotation speed. That is, when the required absorption torque of the hydraulic pump for operating the operating part is smaller than a predetermined set value, the electric motor is rotated and driven by the surplus torque to generate electric power, and the generated electric energy is stored in the electric storage means. On the other hand, if the required absorption torque is larger than the above set value, the electric motor is rotated and driven by the electric energy stored in the power storage means to assist the hydraulic pump with the shortage of the engine output torque at the above rated speed. It is conceivable to perform an assist operation that performs the following.

However, in the case of the above-mentioned configuration, even if an attempt is made to operate the electric motor in response to a heavy load work request, if the electric energy of the power storage means is insufficient, it is not possible to obtain an assist torque by the assist operation. ,
In addition, even if the maximum assist torque determined by the capacity of the electric motor is exerted, heavy load work requirements may not be satisfied. In both of these cases, the required absorption torque is insufficient and engine stall (stall) may occur. Become. On the other hand, when the heavy load work request is temporary and most of the time is the standard load work, the motor continues to generate power, so that the engine operates at a constant speed even when the charging of the power storage means is full. , And the battery is overcharged, or the generated electric energy is wastefully discarded. Further, even when the switching between the power generation operation and the assist operation of the electric motor is controlled by comparing the required absorption torque with the set value, for example, during heavy load work, the operator of the hydraulic shovel may be able to control the electric storage means. It is necessary to perform an operation for a heavy load operation after confirming the remaining amount of energy and the like, and there is also an inconvenience that the operation becomes complicated.

Further, in a hydraulic shovel, the rotating inertia of the revolving superstructure is extremely large, and the revolving superstructure is often operated simultaneously with a bucket, an arm or the like. 4)
In order to operate the hydraulic pump with the hydraulic oil supplied from the same hydraulic pump (2), the hydraulic pump (2) and the engine (1) for driving the hydraulic pump (2) must be changed to those with large torque. Inevitably, the first disadvantage is caused. On the other hand, it is conceivable that the turning drive system is separated from the hydraulic pump (2) and operated by an electric motor. However, it is difficult to drive only with an electric motor.

The present invention has been made in view of such circumstances, and an object of the present invention is to improve the absorption torque of a hydraulic pump while using an engine having the same capacity as that of the related art. In order to improve the fuel consumption rate and to further reduce the noise by reducing the required absorption torque required for the engine and to reduce the load applied to the engine, the hydraulic drive pump (2) is separated from the turning drive system. Another object of the present invention is to regenerate rotational kinetic energy from a revolving structure having a large inertia while reducing the size of the engine (1).

[0014]

According to one aspect of the present invention, there is provided an engine (1), a hydraulic pump (2) driven by the engine (1), and a hydraulic pump (2). It is assumed that the hydraulic drive device includes an operation unit (3a, 3b) driven by pressure oil discharged from (2). In this apparatus, a first 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 first electric motor (8). ) And a swing drive system (400) for rotatingly driving the swing body (32). Then, the first electric motor (8) receives the torque transmitted from the hydraulic pump (2) and stores the electric energy generated in the electric storage means (10) in a power generation operation, and the electric energy is stored in the power storage means (10). The hydraulic pump (2) can be switched to an assist operation for transmitting torque to the hydraulic pump (2) by being driven by receiving the electric energy. Pressure accumulating means (12) for storing energy;
A pump motor device (4) configured to be switchable between a motor operation driven by the supply of the pressure oil from 2) and a pump operation of supplying the pressure oil to the pressure accumulating means (12) to accumulate the pressure. It is configured to be provided.

In the case of the above configuration, the required absorption torque of the hydraulic pump (2) absorbed from the engine (1) is reduced by the operating portion (3).
a), 3b) is determined according to the driving force required, and the operating parts (3a, 3b) are in the standard load operating state, and the required absorption torque of the hydraulic pump (2) is larger than the maximum generated torque of the engine (1). When it is smaller, the first motor (8) is switched to the power generation operation, and the surplus torque of the generated torque of the engine (1) is transmitted to the first motor (8),
The electric energy generated by the power generation operation is stored in the power storage means, and the engine (1) as a driving source can be used efficiently. On the other hand, at the time of heavy load work in which the required absorption torque becomes larger than the maximum generated torque of the engine (1), the first electric motor (8) is switched to the assist operation and stored in the power storage means (10). It is driven by the applied electric energy and functions as a motor for driving the hydraulic pump (2). Thus, the hydraulic pump (2) receives torque transmitted from the first electric motor (8) and is operated with a torque larger than the maximum generated torque of the engine (1). It becomes possible to supply pressure oil necessary for performing heavy-load work. That is, the absorption torque of the hydraulic pump (2) can be made larger than the maximum generated torque of the engine (1). First electric motor (8) capable of switching between the above-described power generation operation and assist operation
For example, an induction motor having a power generation function, a synchronous motor, or the like may be used. According to such a hydraulic drive device, as described above, the first electric motor (8) is switched to the power generation operation at the time of the standard load operation, whereby the engine torque is efficiently used, and the assist operation is performed at the time of the heavy load operation. In addition to the above, it is possible to increase the power of the driving of the operating portion by switching to, for example, the operation of the present hydraulic drive device, the first electric motor (8) is mainly in the power generation operation state in the daytime, and the first electric motor is operated in the nighttime. The electric motor (8) is set in the assist operation state, and the hydraulic pump (2) is mainly used as the first electric motor (8).
By operating the vehicle as a drive source, it is possible to reduce the noise of the engine (1) and achieve a quiet operation.

Further, in the turning drive system (400),
Since the pump motor device (4) for driving the revolving superstructure (32) having a large inertial load is driven by the pressure oil supplied from the pressure accumulating means (12), the required absorption torque of the hydraulic pump (2) And the load applied to the engine (1) can be reduced. For this reason,
It is possible to improve the fuel consumption rate and reduce the noise by operating the engine (1) at the rated speed. In addition, since the pump motor device (4) is switched to the pump operation and supplies pressure oil to the pressure accumulating means (12),
It becomes possible to regenerate the rotational kinetic energy associated with the rotation of the pump motor device (4) to the pressure accumulating means (12), thereby making it possible to save energy.

According to a second aspect of the present invention, in the first aspect of the present invention, an absorption torque detection for detecting a required absorption torque in the hydraulic pump (2) required for driving the operating portions (3a, 3b). Means (11) and the required absorption torque detection value detected by the absorption torque detection means (11) is higher than a predetermined output torque set value of the engine (1) in relation to the rotation speed of the engine (1). When the torque is on the low torque side, the electric motor (8) is operated to generate electric power by the surplus torque transmitted from the hydraulic pump (2), while the required absorption torque detection value is on the higher torque side than the output torque set value. At this time, first switching control means (92) for switching control of the operation of the electric motor (8) so as to bring the electric motor (8) into the assist operation state, and the absorption torque detecting means (1).
When the required absorption torque detection value detected in 1) is on the higher torque side than the output torque setting value, the required absorption torque detection value becomes the maximum assist torque by the assist operation of the electric motor to the output torque of the engine (1). When the assist torque of the electric motor (8) is equal to or greater than the assist limit torque value, the assist torque of the electric motor (8) is increased to the maximum assist torque while maintaining the rotational speed of the engine (1) equal to the absorption horsepower based on the required absorption torque. Engine speed correction control means (9) for changing and correcting to a higher speed side so as to be smaller than
1).

In the above configuration, in addition to the operation according to the first aspect of the present invention, the required absorption torque of the hydraulic pump (2) is obtained by adding the maximum assist torque by the first electric motor (8) to the torque generated by the engine (1). When performing an excessively heavy load work that is larger than the work, the first switching control means (92) assists the first electric motor (8), and at the same time, the rotation speed correction control means (91). ), The rotation speed of the engine (1) is changed and corrected to the higher rotation speed side. This change in the rotation speed makes it possible to reduce the required absorption torque for exhibiting the same absorption horsepower as compared with the rotation speed before the change correction, and the assist torque by the first electric motor (8) becomes the maximum. Anything within the assist torque will be sufficient. For this reason, even for the work request of the heavy load operation temporarily generated as described above, the necessary absorption horsepower can be exerted by the assist operation by the first electric motor (8) without inducing the engine stall. become.

According to a third aspect of the present invention, in the first aspect of the present invention, an input detecting means (18) for receiving an operation by an operator and detecting an operation amount as a rotation speed input value to the pump motor device (4). Rotation speed detecting means (19) for detecting the actual rotation speed of the pump motor device (4), and second switching control means (171, 172) for switching and controlling the operation of the pump motor device (4). The second switching control means (171, 172) is provided so that the rotation speed detection value detected by the rotation speed detection means (19) is larger than the rotation speed input value detected by the input detection means (18). When the rotation speed is lower, the pump motor device (4) is operated by a motor to increase the speed. On the other hand, when the rotation speed detection value is higher than the rotation speed input value, the pump motor device (4) is increased. It is an arrangement for decelerating device (4) by pumping.

In the case of the above configuration, the operation of the pump motor device (4) according to the first aspect of the present invention is specifically specified. That is, the input speed detecting means (18) detects the rotation speed input value in accordance with the operation amount by the operator, and the actual rotation speed of the pump motor device (4) is detected by the rotation speed detecting means (19). Is done. And
When the actual speed of the pump motor device (4) is lower than the rotational speed input value, the second switching control means (171, 171)
By 172), the pump motor device (4) is switched to the motor operation, and the speed is increased by receiving the pressure oil supplied from the pressure accumulating means (12). On the other hand, when the actual rotation speed of the pump motor device (4) is higher than the rotation speed input value, the pump motor device (4) is switched to the pump operation by the second switching control means (171, 172). , While supplying pressure oil to the pressure accumulating means (12),
It is decelerated by the oil pressure in 2). That is, the pump motor device (4) can be driven without applying a load to the engine (1) in accordance with the rotation speed input by the operator. Effects such as low noise, improved fuel efficiency, and energy saving can be reliably obtained. The input detecting means (18) may be constituted by, for example, an operating lever and a potentiometer for detecting an operation amount of the operating lever, and the rotational speed detecting means (19) may be a rotating shaft of a pump motor device (4). A rotation speed sensor or the like for detecting the rotation speed such as (41) may be used.

According to a fourth aspect of the present invention, the pump motor device (4) according to the third aspect of the present invention is provided by changing the variable swash plate (44).
And a second swash plate type piston pump motor provided with a swash plate (4, 7).
The swash plate angle control section (171) for controlling the increase / decrease of the tilt angle of 4) between the forward and reverse large tilt angles is provided.

In the above configuration, the tilt angle of the variable swash plate (44) is controlled by the swash plate angle control unit (171), and the direction of the variable swash plate (44) is reversed.
The pump motor device (4) can be reliably switched to the pump operation or the motor operation, whereby the operation according to the third aspect of the present invention can be reliably obtained. Further, by changing the tilt angle of the variable swash plate (44), it is possible to change the displacement of the pump motor device (4) and to control the change of the absorption torque or output torque and the rotation speed thereof, This makes it possible to smoothly change and control the rotation speed of the pump motor device (4).

According to a fifth aspect of the present invention, in the third aspect of the invention, a power generation operation of storing electric energy generated by receiving torque transmission from the pump motor device (4) in the power storage means (10), and the power storage operation A second electric motor (16) configured to be switched to an assist operation for transmitting torque to the pump motor device (4) by being driven by receiving the electric energy stored in the means (10). Configuration.

In the above configuration, in addition to the operation according to the third aspect of the present invention, the second motor (16) is configured to be switchable between a power generation operation and an assist operation, and the pump motor device (4) during the power generation operation. While receiving torque transmission from
Since the torque is transmitted to the pump motor device (4) during the assist operation, the maximum output torque of the pump motor device (4) can be improved by the assist operation, and the power generation can be performed. By operation, it becomes possible to convert rotational kinetic energy exceeding the capacity of the pressure accumulating means (12) into electric energy and regenerate it. For this reason, it is possible to reduce the capacity of the pressure accumulating means (12) and the pump motor device (4), thereby making it possible to downsize the entire hydraulic drive device.

According to a sixth aspect of the present invention, in the fifth aspect of the present invention, the rotational speed input value detected by the input detecting means (18) and the rotational speed detected value detected by the rotational speed detecting means (19) are used. Is equal to and not zero, a third control for switching the operation of the second motor (16) so as to switch the second motor (16) to the assist operation state.
The configuration includes a switching control means (173).

In the above configuration, in addition to the operation according to the fifth aspect of the present invention, when the rotation speed detection value and the rotation speed input value are equal and not zero, that is, when the pump motor device (4) has a constant rotation speed. The second motor (16) is assisted when rotating at the speed, and the assisting operation can maintain the rotational speed of the pump motor device (4) against the frictional resistance of the rotary sliding portion. Therefore, it is not necessary to supply pressure oil from the pressure accumulating means (12) when the pump motor device (4) is rotated at a constant speed, thereby making the pressure accumulating means (12) compact with a small capacity. This makes it possible to reduce the size of the entire hydraulic drive device.

According to a seventh aspect of the present invention, in the sixth aspect, the second switching control means (171, 172) includes:
When the rotation speed input value and the rotation speed detection value are equal and not zero, the pump motor device (4) is switched to the pump operation.

In the above configuration, in addition to the operation according to the sixth aspect of the present invention, when the rotation speed detection value and the rotation speed input value are equal and not zero, that is, when the pump motor device (4) has a constant rotation speed. When rotating at a speed, the pump motor device (4) is pumped by the assisted second electric motor (16), and the pump motor device (4)
To supply pressure oil to the pressure accumulating means (12). This makes it possible to compensate for a decrease in pressure energy in the pressure accumulating means (12) due to frictional resistance of the rotary sliding portion and leakage of pressure oil from the hydraulic circuit.

According to an eighth aspect of the present invention, there is provided the third switching control means (173) according to the sixth aspect of the present invention, wherein the deviation between the rotation speed input value and the rotation speed detection value is applied to the pump motor device (4). When the deviation is larger than a preset deviation set according to the load, the second electric motor (16) is set to a cut-off state in which torque transmission with the pump motor device (4) is cut off. It is.

In the above configuration, in addition to the operation according to the sixth aspect, the deviation between the actual rotation speed of the pump motor device (4) and the input value of the rotation speed is larger than the set deviation. When a large inertial load is applied to the pump motor device (4), the second switching control means (173) controls the second
The electric motor (16) is turned off. Therefore, when the rotation speed of the pump motor device (4) is rapidly increased or decreased, the second electric motor (16) is turned off to apply a large torque load to the second electric motor (16). In the second place, so that the second
It is possible to improve the durability of the electric motor.

According to a ninth aspect of the present invention, when the rotation speed detection value is lower than the rotation speed input value, the third switching control means (173) according to the sixth aspect of the present invention, ) Is assisted, and when the rotation speed detection value is higher than the rotation speed input value,
The operation of the second electric motor (16) is switched and controlled so that the second electric motor (16) is operated to generate electric power.

In the above configuration, in addition to the operation according to the sixth aspect, the switching operation of the second motor (16) by the third switching control means (173) causes the motor operation of the pump motor device (4). At the same time, the speed-up rotation is surely assisted, while the rotation kinetic energy exceeding the capacity of the pressure accumulating means (12) can be surely regenerated during the operation of the pump.

According to a tenth aspect of the present invention, in the first aspect, a pressure accumulating auxiliary means (48) for supplying pressure oil to the pressure accumulating means (12) to accumulate pressure is provided.

In the case of the above construction, in addition to the operation according to the first aspect of the present invention, the pressurized oil is supplied to the pressure accumulating means (12) by the pressure accumulating auxiliary means (48), thereby rotating the pump motor device (4). It is possible to compensate for a decrease in pressure energy in the pressure accumulating means (12) due to sliding friction and leakage of pressure oil from the hydraulic circuit.

According to an eleventh aspect of the present invention, the second electric motor (16) according to any one of the fifth to ninth aspects is characterized in that the second electric motor (16) is a rotary shaft (41) of a pump motor device (4).
, And the second motor (16) and the pump motor device (4) are integrally assembled.

In general, when the electric motor (16) is combined with the pump motor device (4), the pump motor device (4) is used to transfer torque between the electric motor (16) and the pump motor device (4). ) Usually needs to be arranged in series with the rotating shaft of the electric motor (16), so that the hydraulic drive device is relatively long in the direction of the rotating shaft (41) of the pump motor device (4). In the above configuration, the second motor (16) is disposed at a position on the outer peripheral side of the pump motor device (4) and is integrally assembled with the pump motor device (4). Because
In particular, the length of the hydraulic drive device in the direction of the rotation shaft (41) can be reduced, and the size can be reduced.

According to a twelfth aspect of the present invention, the pump motor device (4) according to the eleventh aspect of the present invention is provided with the rotary shaft (4).
A cylinder block (42) that rotates integrally with the cylinder block (1), a housing (45) covering the periphery of the cylinder block (42), and a second electric motor (1).
6), a rotor (161) attached to a position on the outer peripheral surface side of the cylinder block (42) so as to rotate integrally with the cylinder block (42), and the rotating shaft (41) with respect to the rotor (161). And a stator (162) attached to the inner peripheral surface side of the housing (45) so as to face the center in the radial direction.

In the case of the above construction, in addition to the operation according to the eleventh aspect of the present invention, the rotor (1) of the second electric motor (16) is provided.
61) is integrally attached to the outer peripheral surface of the cylinder block (42) of the pump motor device (4).
Since the stator (162) of the electric motor (16) is mounted on the peripheral side of the housing (45) of the pump motor device (4), the second electric motor (16) itself is mounted on the housing of the pump motor device (4). (45) will be integrally disposed. Therefore, the heat generated by the operation of the second electric motor (16) is cooled by the oil of the pump motor device (4), and the temperature rise is suppressed.

[0039]

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

FIG. 6 shows an embodiment in which the hydraulic drive device according to the embodiment of the present invention is applied to a hydraulic shovel. 1 is an engine, 2 is a variable displacement hydraulic pump driven by the engine (1), and 3a is Traveling hydraulic motor as an operating part,
Reference numeral 3b denotes a cylinder for operating a bucket, an arm, a boom or the like as an operating portion, and 4 denotes a revolving body (3) having a large inertia load.
A swing pump motor as a variable swash plate type piston pump motor for driving 2) controls the direction and amount of pressure oil supply to the traveling hydraulic motor and cylinder (hereinafter, both are collectively referred to as a work actuator). The control valve 6 is a variable swash plate (21) of the hydraulic pump (2).
A tilting actuator for changing the angle of the swash plate; 7 a control valve for controlling the operation of the tilting actuator (6) to control the flow rate of oil discharged from the hydraulic pump (2); A first electric motor 9 which is constituted by an induction motor also serving as a motor and reversibly transmits torque to and from the hydraulic pump (2), and 9 is an operation of the first electric motor (8), the control valve (7) and the engine (1). Is a power storage means connected to the first electric motor (8) via the controller (9), and 11 is an absorption torque detection means for detecting a required absorption torque of the hydraulic pump (2). .

Reference numeral 12 denotes the above-mentioned swirl pump motor (4).
An accumulator as pressure accumulating means for transferring pressure oil between the pump pump and the control pump; 13 is a control valve for controlling the direction and amount of pressurized oil supplied to the swirl pump motor (4); A tilt actuator for changing the angle of the swash plate of the variable swash plate (44), a control valve 15 for controlling the operation of the tilt actuator (14), and a rotary pump 16 constituted by an induction motor also serving as a generator A second electric motor 17 that reversibly transmits torque to and from the motor (4) is a second electric motor (1).
6) and a swivel controller for controlling the operation of the two control valves (13 and 15). An input detecting means 18 receives an operation by an operator and detects the operation amount as a rotational speed input value to the swivel pump motor (4). , 19 are rotation speed detecting means for detecting the actual rotation speed of the swirl pump motor (4). The swivel pump motor (4) and the components (12, 13, 14, 15, 16) from the accumulator to the second electric motor constitute a swivel drive system (400).

First, the turning drive system (400)
Components other than the above will be described in detail.

The engine (1) is constituted by a diesel engine, and is controlled by a governor (1a). The governor (1a) normally maintains the engine (1) at a constant rotation speed at a constant rotation speed Nb (see FIG. 7) described later, while the controller (9) operates according to the operating state of the hydraulic excavator. Upon receiving a rotation speed control signal from a rotation speed correction control unit (91) described later, the rotation speed of the engine (1) is changed, and the engine (1) is operated at the changed rotation speed. .

The hydraulic pump (2) is configured as a motor-integrated hydraulic pump (20) which is integrally assembled with a first electric motor (8) and rotates in conjunction with the first electric motor (8). When the variable swash plate (21) is tilted by the tilt actuator (6) provided, an amount of pressure oil corresponding to the tilt angle of the variable swash plate (21) is supplied to the control valve (5). Supply. That is, the control valve (7) is switched and controlled in accordance with the work load of each work actuator (3a, 3b) based on the operation amount of each operation lever (not shown) by the operator of the excavator, and the tilt actuator ( The variable swash plate (21) is tilted in accordance with the operation amount of (6). Then, a predetermined amount of pressure oil is discharged by changing the stroke amount of the piston row according to the change of the variable swash plate angle. The operation of the first electric motor (8) is switched between a power generation operation and an assist operation by a switching control signal from a switching control section (92) of the controller (9) described later.

The controller (9) controls a first switching control section (92) as first switching control means for switching the operation of the first electric motor (8) between a power generation operation and an assist operation, and a governor (1a). A rotation speed correction control unit (91) as rotation speed correction control means for outputting a rotation speed control signal to change and correct the rotation speed of the engine (1) is provided.

As shown in FIG. 7, the first switching control section (92) includes a rotational speed / torque characteristic Et- which is an engine torque characteristic determined by the output torque and the rotational speed of the engine (1).
Nb and Et-Na are input and set in advance as output torque set values, and the first switching control unit (92) determines that the required absorption torque detection value of the hydraulic pump (2) detected by the absorption torque detection means (11) is the above-mentioned value. When the output torque set value is smaller than the output torque set value, the first motor (8) is switched to the power generation operation, while when the required absorption torque detection value is larger than the output torque set value, the first motor (8) is switched to the assist operation. It has become. Here, the rotation speed / torque characteristic Et-Nb indicates the torque generated by the engine (1) when the rotation speed of the engine (1) is Nb, and the rotation speed / torque characteristic Et-Na indicates the engine (1). This shows the generated torque when the rotation speed is Na. The rotation speed Nb is set to, for example, the rotation speed near the rated point, and the minimum fuel consumption rate ge1
(See Fig. 3)
As the rotation speed Na, for example, a rotation speed near the maximum horsepower point of the engine (1) is set.

During the power generation operation, the frequency of the current flowing through the first motor (8) is converted by an inverter circuit built in the controller (9), and the hydraulic pump ( 2) The torque acts on the side that brakes the rotation, whereby the difference between the transmission torque from the engine (1) to the hydraulic pump (2) and the required absorption torque of the hydraulic pump (2) is obtained. Is absorbed by the first motor (8) to generate electric power, and the generated electric energy is stored in the electric storage means (1).
0). On the other hand, at the time of assist operation, the first electric motor (8) acts on the hydraulic pump (2) by the frequency conversion so that torque acts on the side of the hydraulic pump (2) on the side that promotes its rotation. By controlling the electric energy flowing to the electric motor (8) by the controller (9), a necessary torque that exceeds the set required output torque by the required absorption torque is applied to the hydraulic pump (2). ing. That is, during the assist operation, the first electric motor (8) functions as a normal drive motor, and assists the drive of the hydraulic pump (2).

The rotation speed correction control section (91)
First, second, and third rotational speed correction controls are performed. In the first rotational speed correction control, when the required absorption torque detection value (for example, d 'in FIG. 7) detected by the absorption torque detection means (11) is on the higher torque side than the output torque set value, The assist limit torque value A obtained by adding the maximum assist torque by the assist operation of the first electric motor (8) to the engine output torque of the engine (1) based on the rotation speed / torque characteristic Et-Nb is the absorption torque detection value d '.
When t is greater than t, assist by the assist operation of the first electric motor (8) is maintained while maintaining the condition that the rotational speed of the engine (1) is equal to the absorption horsepower H0 based on the required absorption torque d '. The torque d ″ is corrected to be higher than Nb so as to be smaller than the maximum assist torque.

That is, in FIG. 7, when the absorption horsepower H0 is required during the operation at the rotation speed Nb, the first rotation speed correction control is performed by increasing the rotation speed and correcting the rotation speed to d ". In other words, the above-mentioned absorption horsepower H0 is exerted, that is, a high heavy-load work request that requires a higher absorption horsepower H0 than that required for normal heavy-load work. Temporarily occurs, the absorption torque d 'is required if the rotation speed is Nb in order to exhibit the absorption horsepower H0. However, the first motor (8) is switched by the first switching control means (92). Even if the operation is switched to the assist operation, the absorption torque d 'exceeds the assist limit torque At.
Will not be able to demonstrate the performance and will cause an engine stall. In such a case, the absorption torque is set to d ″ by changing the rotation speed of the engine (1) from Nb to a higher rotation speed by a predetermined amount by the first rotation speed correction control, and the absorption torque is set at the rotation speed Nb. An absorption horsepower H0 equal to the torque d 'is exerted.

The dashed line indicated by H2 in FIG. 7 is an iso-horsepower curve of the absorption horsepower required for the standard load operation, and the dashed line indicated by H1 is the iso-horsepower curve of the absorption horsepower required for the heavy load operation. The dashed-dotted line indicated by H0 is an iso-horsepower curve of the absorption horsepower required for a heavier heavy load operation.

In the second rotational speed correction control, the absorption horsepower H1 (heavy load operation) is required from the case of the required absorption horsepower H2 (standard load operation) at point c in FIG.
In the case where the operation of the first electric motor (8) is switched to the assist operation and shifts to the point d according to 2), the detected value of the charged amount by the charged amount detecting means (101) described later is larger than the charged amount required for the assist operation. When the engine speed is small, the engine speed (Nb) of the engine (1) is changed to the engine speed (Na) and corrected to a higher engine speed, and the required absorption torque at the point (d) is equal to the horsepower curve H
A, which is the intersection of 1 with the rotation speed / torque characteristic curve Et-Na
It changes to the absorption torque of the point.

That is, when a heavy load work request is made while the standard load work is being performed at the point c, in a normal case, the first motor (8) is moved to the point d by the assist operation to absorb the horsepower H1. However, there are times when the amount of stored power for performing the assist operation is insufficient.
In such a case, the rotation speed of the engine (1) is changed and corrected to the higher rotation speed side by the second rotation speed correction control, whereby the shift from the point c to the point d, that is, the first electric motor (8) The switching to the assist operation of (1) is prohibited, and the operation is shifted to the point (a) instead of the point (d) so that the above-described absorption horsepower H1 is exhibited while the operation of the first electric motor (8) is in the power generation operation.

In the third rotation speed correction control, when the first electric motor (8) is switched to the power generation operation by the first switching control unit (92), the storage amount detecting means (101) described later.
If the detected value of the charged amount corresponds to the saturated state range of the power storage means (10), the rotation speed of the engine (1) is changed to a lower rotation speed while maintaining the absorption horsepower equal. The amount of charge by the power generation operation is reduced, or the operation of the first electric motor (8) is changed to the assist operation.

That is, when the heavy load work at the point a is continued, the power storage means (10) is continuously charged by the power generation operation of the first electric motor (8), and the power storage means (10) is saturated. Or the heavy load work at the point a is absorbed horsepower H
When the operation is switched to the standard load operation at the point 2b, the amount of charge to the power storage means (10) by the power generation operation of the first electric motor (8) further increases, and the power storage means (10) is quickly saturated. May be reached. However, the storage means (10)
When the charged amount of the battery becomes saturated, even if the battery is charged any more, the electric energy cannot be effectively used and the battery is discarded. Therefore, in such a state, the rotation speed of the engine (1) is changed and corrected from Na to a lower rotation speed side, that is, the rated point side by the third rotation speed correction control, and the above-mentioned heavy load is corrected. During load operation (at the required absorption horsepower H1), the point is shifted from the point a to point d. During standard load operation (at the required absorption horsepower H2), the point is shifted from the point b to the point c. Absorbing horsepower H1
Alternatively, the efficiency of the operation of the engine (1) and the noise can be reduced while exhibiting the same absorption horsepower as H2.

At this time, in the third rotation speed correction control, the change correction to the lower rotation speed side is performed at the rotation speed (minimum rotation speed) corresponding to the maximum swash plate angle of the variable swash plate (21) of the hydraulic pump (2). Number). That is, when the rotation speed Nb is set to, for example, the minimum rotation speed described above, the rotation speed is limited to a value lower than the rotation speed Nb so that the change is not corrected, and the control limit in the control of the variable swash plate (21) is reduced. The above-mentioned change correction to the low rotation speed side is performed within the range not exceeding.

The power storage means (10) may be constituted by a capacitor or the like in addition to a battery (secondary battery). The power storage means (10) detects the amount of stored power by a voltage value and sends it to the controller (9). Output power detection means (1
01) is attached. The required absorption torque is detected by the absorption torque detecting means (11) directly by a pressure sensor and a swash plate angle sensor normally provided in the hydraulic pump (2), and also by the engine (1) detected by the governor (1a). ) May be performed indirectly by a minute change in the number of revolutions.

Next, the turning drive system (400) will be described.

As shown in detail in FIG. 8, the swirl pump motor (4) is configured as a second electric motor integrated hydraulic pump motor (40) in which a second electric motor (16) is integrally assembled. That is, the swing pump motor (4)
Is a rotary shaft (41) connected to a rotary center shaft (31) of a rotary system (30) via a coupling (32), and a cylinder block spline-coupled to the rotary shaft (41) and integrally rotating. (42), a piston row (43) composed of a plurality of pistons built in a circumferential direction inside the cylinder block (42), and a piston row (43)
A variable swash plate (44) for controlling the stroke amount of the above, and a housing (45) containing these to form a closed structure. On the other hand, the second electric motor (16) has a rotor (16).
1) and a stator (162), and the rotor (161) is arranged so as to be pressed into the outer peripheral surface of the cylinder block (45) and rotate integrally with the cylinder block (45). The stator (162) is pressed into the inner peripheral surface of the housing (45) so as to face the rotor (161) in the radial direction, and is fixed in a non-rotating state. That is, the second electric motor (16) is disposed at a position on the outer peripheral side of the cylinder block (42) centering on the rotating shaft (41), and is integrally encased by the housing (45).

The above-mentioned swirl pump motor (4)
The variable swash plate (44) is tilted by a tilt actuator (14) provided in the housing (45), and the rotary shaft (41) is driven to rotate, thereby causing the variable swash plate (44) to rotate. The cylinder block (45) is rotated with respect to the variable swash plate (44), and the piston train (43) is reciprocated, whereby an amount of pressure oil corresponding to the swash plate angle is supplied to the control valve (13). A pump operation for supplying the accumulator (12) to the above-mentioned accumulator (12) is performed. On the other hand, the revolving pump motor (4) receives the supply of the pressure oil from the accumulator (12) and reciprocates the piston train (43), whereby the cylinder block (45) moves the variable swash plate. The motor (44) is rotated to operate the motor for driving the rotary shaft (41). That is, the variable swash plate (44) is connected to the turning controller (1).
The control valve (15) is switched and controlled by a swash plate angle control signal from a swash plate control unit (171) described later in 7),
The piston is tilted in accordance with the operation amount of the tilt actuator (14), and the reciprocating stroke of the piston row (43) is changed in accordance with the change of the variable swash plate angle. Pressure oil is discharged or sucked. Further, the second electric motor (16) is provided with a third switching control unit (17) described later of the turning controller (17).
The operation is switched between the power generation operation and the assist operation by the switching control signal from 3).

The slewing controller (17) switches the swash plate angle control unit (171) for increasing or decreasing the swash plate angle of the variable swash plate (44) of the slewing pump motor (4), and switches the control valve (13). The second switching control unit (17)
2), and both constitute second switching control means. Further, third switching control as third switching control means for switching the operation of the second electric motor (16) between the power generation operation and the assist operation. (173).

The swash plate angle control unit (171) and the second switching control unit (172) are provided with a rotation speed input value obtained by detecting the actual rotation speed of the swing pump motor (4) by the input detection means (18). When the rotation speed is lower than the rotation speed input value, the rotation pump motor (4) is motor-operated to increase the speed. On the other hand, when the actual rotation speed is higher than the rotation speed input value, the rotation pump motor (4) is increased. The operation of the swivel pump motor (4) is switched and controlled so that the pump is operated to decelerate. That is, when the rotation speed detection value detected by the rotation speed detection means (19) is lower than the rotation speed input value detected by the input detection means (18), the second switching control unit (172) The control valve (13) is switched to the upper position in FIG. 6 to supply the pressurized oil from the accumulator (12) to the turning pump motor (4), and at the same time, the swash plate angle control unit (171) performs The variable swash plate (44) of the pump motor (4) is tilted to the side where the swivel pump motor (4) is to be operated by the supply of the pressure oil. Thereby, the swirl pump motor (4)
Converts the kinetic energy of the pressure oil supplied from the accumulator (12) into rotational kinetic energy to rotate the revolving superstructure (32) at an increased speed. On the other hand, when the rotation speed detection value is higher than the rotation speed input value, the second switching control unit (172) switches the control valve (13) to the lower position in FIG. ) Side to allow only the flow of pressurized oil from the accumulator (12) side, and at the same time, the swash plate angle control section (171) rotates the variable swash plate (44) of the swivel pump motor (4). Operating swivel pump motor (4)
Is tilted to the side where the pump will operate due to its rotation. As a result, the swing pump motor (4)
The rotational kinetic energy of the revolving system (30) is converted into pressure energy to accumulate pressure in the accumulator (12), and the revolving body (32) is decelerated and rotated. Further, the swash plate angle control unit (171) controls the second swash plate angle.
The tilt angle of the variable swash plate (44) is controlled to increase or decrease according to the control state of the electric motor (16).

The third switching control section (173) controls the actual rotational speed of the rotary pump motor (4) and the input detecting means (1).
The second value according to the deviation from the rotation speed input value input in 8)
The operation of the electric motor (16) is switched between a power generation operation and an assist operation. That is, the third switching control unit (173) applies an excessively large operating load to the pump motor device (4) when driving the revolving unit (32) because the deviation is larger than the preset deviation. In this case, the second electric motor (16) is set to a cut-off state in which the transmission of torque with the swing pump motor is cut off, and when the deviation is smaller than the set deviation and is not zero, Activates the second motor (16) when the rotation speed detection value is lower than the rotation speed input value, and on the other hand, when the rotation speed detection value is higher than the rotation speed input value. The operation of the second electric motor (16) is switched and controlled so that the electric motor (16) operates to generate electric power. Further, the third switching control unit (173) performs the operation when the rotation speed detection value and the rotation speed input value are equal and not zero, that is, when the swing pump motor (4) is rotating at a constant rotation speed. Then, the second electric motor (16) is set to the assist operation state.

During the power generation operation, the frequency of the current flowing through the stator (162) is converted by the inverter circuit built in the turning controller (17) and acts on the rotor (161) from the stator (162). The magnetic force causes the rotor (161) to be rotationally driven by the rotational inertia of the rotating body (32).
Act on the side that brakes the rotation of
Part of the torque transmitted from the revolving unit (32) to the revolving pump motor (4) is absorbed by the second electric motor (16) to generate electric power, and the generated electric energy is stored in the electric storage means (1).
0). On the other hand, during assist operation, the stator (1
62) so that the magnetic force acting on the rotor (161) acts on the side promoting the rotation of the rotor (161).
By controlling the electric energy flowing from the power storage means (10) to the stator (162) by the turning controller (17), the second electric motor (16) serves as a normal drive motor and turns. The driving of the pump motor (4) is assisted.

Reference numeral 48 denotes the accumulator (12)
Is a hydraulic pump as a pressure accumulating auxiliary means for compensating for a decrease in pressure energy in the accumulator (12) by supplying pressure oil to the hydraulic pump (4).
8) may be operated by a dedicated electric motor or the like when the pressure energy in the accumulator (12) falls below a certain limit.

Next, the operation of the turning drive system (400) will be described with reference to FIG.

First, when the operator of the excavator operates the operating lever of the turning drive system (400) in the stopped state at time t1, the operation amount is detected as the rotational speed input value ω1 by the input detecting means (18). Is done. Here, since the rotation speed detection value detected by the rotation speed detection means (19) is zero, the variable swash plate (44) of the swing pump motor (4) is tilted to the maximum by the swash plate angle control unit (171). The second switch control unit (172)
Thereby, the control valve (13) is switched to the upper position. Therefore, the displacement of the swirl pump motor (4) becomes the maximum value q1 and the flow rate of the pressure oil supplied from the actuator (12) becomes maximum. The motor is operated by the output, and the rotation speed of the revolving unit (32) increases. Then, at time t2, the deviation between the detected rotational speed ω2 and the input rotational speed ω1 becomes smaller than a preset deviation set in advance according to the inertial load applied to the swing pump motor (4). 4) After the applied inertia load becomes sufficiently small, the third switching control unit (173) switches the second electric motor (16) to the assist operation state, and assists the motor operation of the swing pump motor (4). (The assist operation by the second electric motor (16) is indicated by a broken line A in FIG. 9). At this time, the frequency of the current flowing through the second electric motor (16) is converted by an inverter circuit built in the turning controller (17), and the torque transmitted from the second electric motor (16) to the turning pump motor (4). Is gradually increased, while the swash plate angle controller (171) decreases the swash plate angle of the variable swash plate (44) to gradually reduce the output torque of the rotary pump motor (4).

At time t3, the rotary pump motor (4)
After the actual rotational speed of the rotary pump coincides with the rotational speed input value .omega.1, the revolving pump motor (4) is rotated at a constant rotational speed. At this time, while the second electric motor (16) is in the assist operation state, the rotary pump motor (4) is switched to the pump operation by slightly tilting the variable swash plate (44), and the second electric motor (16) is switched to the pump operation. By the assist operation of (2), the pressure oil is supplied to the accumulator (12) to accumulate the pressure. That is, by the assist operation of the second electric motor (16) (indicated by a broken line B in the figure), the rotation of the rotary pump motor (4) is maintained, and the accumulator (1) is maintained.
The reduction in pressure energy in 2) is compensated.

Next, at time t4, when the operator of the hydraulic excavator operates the operation lever to the opposite side to stop the rotation of the revolving unit (32) and returns the operation amount to zero, the rotation speed input value is obtained. Becomes zero and becomes lower than the detected rotation speed ω1, so that the swash plate angle controller (171) tilts the variable swash plate (44) of the swing pump motor (4) to the maximum tilt angle. At the same time, the control valve (13) is switched to the lower position by the second switching control section (172). For this reason, the swivel pump motor (4) is pumped with its displacement being at the maximum value -q1 and its absorption torque is maximized. Thereby, the revolving superstructure (3)
The rotational kinetic energy of 2) is efficiently converted into pressure energy and regenerated by the accumulator (12), and the rotation of the revolving body (32) is rapidly reduced. Further, since the deviation between the rotation speed ω1 of the swing pump motor (4) and the rotation speed input value (zero) is larger than the set deviation, the second switching motor (173) turns off the second electric motor.

At time t5, when the deviation between the rotation speed ω3 of the swing pump motor (4) and the rotation speed input value (zero) becomes smaller than the set deviation, the third switching control unit (173) controls the second motor. (16) is switched to the power generation operation state, and the rotational kinetic energy of the rotating body (32) is converted into electric energy and regenerated to the power storage means (10) (the power generation operation by the second electric motor (16) is the same). (Indicated by a broken line C in the figure). At this time, in the same manner as in the above-described assist operation, the swirl pump motor (4) is switched to the second electric motor (1).
While the torque transmitted to 6) is gradually increased, the swash plate angle controller (171) gradually reduces the swash plate angle of the variable swash plate (44) to gradually reduce the absorption torque of the swing pump motor (4). I do. Then, after the swash plate angle of the swirl pump motor (4) becomes zero and the absorption torque becomes zero, the swirl pump motor (4) is decelerated and rotated while the second electric motor (16) is operated to generate electric power. It stops at t6.

According to the present embodiment having the above configuration, usually,
The first electric motor (8) uses a part (excess torque) of the engine output torque while maintaining the rotation operation of the engine (1) at the rotation speed Nb to exhibit the required absorption horsepower H2 in the standard load operation.
(See point c in FIG. 7), and if there is a heavy load work request, the first switching control unit (92) switches the first electric motor (8) to the assist operation, and the assist torque is reduced to the engine torque. In addition to the output torque, the absorption horsepower H1 required for the heavy load operation can be exerted (see point d in FIG. 7). As a result, torque assist for the hydraulic pump (2) during heavy-load work can be performed using the electric energy stored during standard-load work.
The driving forces of the two engines (1) can be effectively used with high efficiency. Then, the standard load operation (absorbed horsepower H2
Returning to point c in FIG. 7, the first switching control unit (9
According to 2), the first electric motor (8) is switched to the power generation operation again, and the electric storage means (10) is charged.

On the other hand, even if a heavier heavy work request requiring an absorption horsepower H0 higher than the above absorption horsepower H1 occurs temporarily, the rotation speed correction control unit (91) performs the first rotation speed correction control. The rotation speed of the engine (1) is changed to a higher rotation speed side by a predetermined amount than Nb (see d ″ in FIG. 7), and the above-mentioned absorption horsepower H0 is exerted by the assist torque of the first electric motor (8). it can.

The standard load operation (absorbed horsepower H2
; A heavy load work request (absorbed horsepower H1) in the middle of point c in FIG.
) Occurs, or the first motor (8) is switched to the assist operation by the heavy load work request, and FIG.
When the amount of power stored in the power storage means (10) is insufficient or the state becomes insufficient, the engine is controlled by the second rotation speed correction control of the rotation speed correction control unit (91). The rotation speed of (1) is changed from Nb to Na, and accordingly, when the former power storage amount is insufficient, the switching system is changed to Na, and thereby, when the former power storage amount is insufficient, the first control is performed. The switching from the power generation operation of the first electric motor (8) to the assist operation by the switching control unit (92) is prohibited, and the power generation operation can be continued at the point a in FIG. 7. Is reached, the first motor (8) can be switched from the assist operation at the point d to the power generation operation at the point a by shifting to the point a.

Further, at the time of heavy load operation at the rotation speed Na (point a in FIG. 7) or at the time of standard load operation (point b in FIG. 7).
In the power generation operation state of the first electric motor (8), when the amount of power stored in the power storage means (10) is saturated or reached, the third rotation speed correction control of the rotation speed correction control unit (91) is performed. The engine (1) rotation speed from Na to Nb
Accordingly, in the case of the heavy load operation, the point is shifted from the point a to the point d in FIG. 7 and the first electric motor (8) is used by using the electric energy of the electric storage means (10) in the saturated state.
In the case of the above-mentioned standard load operation, the operation is shifted from the point b to the point c in FIG. As a result, wasteful generation of electric energy can be reduced. In addition, the number of revolutions of the engine (1) can be made lower, and the noise can be reduced as a whole while maintaining the power storage amount of the power storage means (10) at a predetermined level.

The rotation speed correction control unit (9)
By the first to third rotational speed correction control in 1), energy saving and hydraulic pump (2) by switching control between the power generation operation and the assist operation of the first electric motor (8) of the first switching control unit (92). In addition to the basic effect of increasing the absorption torque of the engine, the noise of the engine can be reduced, and the operation and efficiency of each of the engine (1) and the hydraulic pump (2) can be improved and optimized.

Further, since the revolving pump motor (4) is driven by the pressure oil supplied from the pressure accumulating means (12),
The required driving torque of the hydraulic pump (2) can be reduced to reduce its required absorption torque,
By reducing the number of revolutions of the engine (1), noise can be reduced and the fuel consumption rate can be improved. In addition, when the rotation operation of the revolving unit (32) is decelerated, the revolving pump motor (4) is switched to the pump operation to supply the pressure accumulating means (12) with pressurized oil, thereby rotating the accumulating means (12). Can regenerate kinetic energy,
Thereby, energy saving can be achieved.

According to the turning drive system (400), the second electric motor (16) assists the rotation of the turning pump motor (4) when the motor is operated, while increasing the speed.
Since the rotational kinetic energy exceeding the capacity of the pressure accumulating means (12) can be efficiently regenerated at the time of operation of the pump, the capacity of the swing pump motor (4) and the pressure accumulating means (12) can be reduced. The drive system (400) can be made compact. Further, when rotating the rotating pump motor (4) at a constant rotation speed, the second
With the assist operation of the electric motor (16), the rotation speed of the swirl pump motor (4) can be maintained and the swirl pump motor (4) can be slightly pumped to supply pressure oil to the pressure accumulating means (12). Thereby, the pressure accumulating means (1) associated with the frictional resistance of the rotary sliding portion and the leakage of the pressure oil.
2) It is possible to compensate for the decrease in pressure energy in the above. Further, when the rotational speed of the pump motor device (4) is to be rapidly increased or decreased, the second electric motor (16) is turned off, so that the second electric motor (1) is turned off.
It is possible to improve the durability by not imposing a large torque on 6). In addition, the rotation pump motor (4) is formed integrally with the second electric motor (16) as described above, so that the rotation shaft ( 41) The increase in the length in the direction can be shortened, the turning drive system (400) can be made compact, and the second electric motor (16) can be cooled by oil cooling on the turning pump motor (4) side. ) It is possible to prevent overheating of the second motor (16) and to maintain the performance and improve the durability of the second electric motor (16).

<Other Embodiments> The present invention is not limited to the above embodiments, but includes various other embodiments. That is, in the above embodiment,
An example in which the present hydraulic drive device is applied to a hydraulic excavator has been described. However, the present invention is not limited to this, and may be applied to any type in which the operating unit is driven by pressure oil supplied from a hydraulic pump. For example, the present invention can be applied to a construction machine or a hydraulic working machine having a revolving structure with a large inertial load.

Further, in the above embodiment, the induction motors (8 and 16) which also serve as induction generators are shown as the first motor (8) and the second motor (16). However, the present invention is not limited to this. Etc. may be used.

In the above embodiment, the dedicated hydraulic pump (48) is used as the pressure accumulating auxiliary means. However, the present invention is not limited to this.
Pressure oil may be supplied from the hydraulic pump (2) to the accumulator (12) when a, 3b) is not operated.

[0080]

As described above, according to the hydraulic drive system according to the first aspect of the present invention, the first electric motor (8) is switched to the power generation operation during the standard load operation, so that the engine torque is efficiently used. In addition, by switching to the assist operation at the time of heavy load work, it is possible to increase the power of the operating unit drive and reduce noise. Further, by driving the pump motor device (4) with the pressure oil supplied from the pressure accumulating means (12), the required absorption torque of the hydraulic pump (2) is reduced to reduce the load on the engine (1). As a result, it is possible to further reduce the noise of the drive unit and improve the fuel consumption rate. In addition, by switching the pump motor device (4) to the pump operation at the time of deceleration, the rotational kinetic energy of the revolving unit (32) can be regenerated, thereby achieving energy saving.

According to the second aspect of the present invention, in addition to the effect of the first aspect of the present invention, the electric motor can be operated without causing engine stall even for a heavy load work request that occurs temporarily. The required absorption horsepower can be exhibited by the assist operation according to (8).

According to the third aspect of the present invention, the pump motor device is based on the rotation speed input value detected by the input detection means (18) and the rotation speed detection value detected by the rotation speed detection means (4). By switching the operation of (4) between the pump operation and the motor operation, it is possible to surely obtain the effects such as the reduction of the noise of the drive unit, the improvement of the fuel efficiency, and the energy saving in the invention of the first aspect.

According to the fourth aspect of the present invention, the tilt angle of the variable swash plate (44) is controlled by the swash plate angle control section (171), so that the effect of the third aspect of the present invention is ensured. In addition to being able to obtain, the displacement of the pump motor device (4) can be changed to change and control the absorption torque or output torque and the rotation speed thereof,
Thus, the rotation speed of the pump motor device (4) can be smoothly changed and controlled.

According to the fifth aspect of the present invention, in addition to the effect of the third aspect of the present invention, the second electric motor (16)
By transferring torque between the pump motor device (4) and the pump motor device (4), the motor operation of the pump motor device (4) is assisted to increase the maximum output torque,
Rotational kinetic energy exceeding the capacity of the pressure accumulating means (12) can be efficiently regenerated, whereby the capacity of the pressure accumulating means (12) and the pump motor device (4) can be reduced to make the entire hydraulic drive device compact. Can be planned.

According to the sixth aspect of the present invention, in addition to the effect of the fifth aspect of the present invention, the second electric motor (16)
, The rotational speed of the pump motor device (4) can be maintained against the frictional resistance of the rotary sliding portion, whereby the pressure accumulating means (12) has a small capacity and the entire hydraulic drive device Can be made more compact.

According to the seventh aspect of the present invention, in addition to the effect of the sixth aspect of the present invention, the pump motor device (4) is operated by the second electric motor (16) which is operated by the assist pump to operate the pressure accumulating means ( By supplying the pressure oil to the pressure storage means (12), it is possible to compensate for a decrease in pressure energy in the pressure accumulating means (12) due to frictional resistance of the rotary sliding portion and leakage of the pressure oil from the hydraulic circuit.

According to the eighth aspect of the present invention, in addition to the effect of the sixth aspect, the second motor (16) is shut off when the speed of the pump motor device (4) is rapidly increased or decreased. By setting it in the state, it is possible to improve the durability of the second electric motor (16) without applying a large torque load to the second electric motor (16).

According to the ninth aspect of the present invention, in addition to the effect of the sixth aspect of the present invention, the pump motor device () is operated by the switching operation of the second electric motor (16) by the third switching control means (173). 4) The assisting of the motor operation and the regeneration of the rotational kinetic energy can be reliably performed.

According to the tenth aspect of the present invention, in addition to the effect of the first aspect of the present invention, the pressure accumulating auxiliary means (4
By supplying the pressure oil to the pressure accumulating means (12) by 8), the pressure energy in the pressure accumulating means (12) due to the rotational sliding friction of the pump motor device (4) and the leakage of the pressure oil from the hydraulic circuit can be reduced. Can compensate.

According to the eleventh aspect of the present invention, in addition to the effect of any one of the fifth to ninth aspects, the rotary shaft of the pump motor device (4) in the hydraulic drive unit is provided. (41) The length in the direction can be shortened, whereby the entire hydraulic drive device can be reduced in size.

According to the twelfth aspect of the present invention, in addition to the effects of the eleventh aspect, the motor (16)
The pump motor device (4) can be integrally disposed in the housing (45) of the pump motor device (4), and the oil cooling function in the pump motor device (4) prevents the electric motor (16) from being heated by the operation of the electric motor (16). Can be planned.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a conventional example of a hydraulic drive device.

FIG. 2 is a torque diagram of the hydraulic pump in the case of FIG.

FIG. 3 is a performance curve diagram showing a relationship between a shaft torque, a shaft output, and a fuel consumption rate with respect to the engine speed in the case of FIG. 1;

FIG. 4 is a time chart showing a correlation among a shaft torque, a shaft output, a rotation speed, and a fuel consumption rate during a standard load operation in FIG. 1;

5 is a time chart showing the interrelation among the shaft torque, the shaft output, the rotation speed, and the fuel consumption rate during the heavy load operation in FIG.

FIG. 6 is a schematic diagram showing an embodiment of the present invention.

FIG. 7 is a diagram illustrating a relationship between an engine speed and an output torque in the embodiment.

FIG. 8 is an enlarged sectional explanatory view of the second electric motor integrated hydraulic pump motor in FIG. 6;

FIG. 9 is a time chart showing a mutual relationship between a rotation speed input value, a displacement of a rotation pump motor, and a rotation speed detection value at the time of turning of the turning drive unit in FIG. 6;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Engine 2 Hydraulic pump 3a Hydraulic motor, work actuator (operating part) 3b Cylinder, work actuator (operating part) 4 Swing pump motor (pump motor device) 8 1st electric motor 10 Power storage means 11 Absorption torque detection means 12 Accumulator (pressure accumulation means) 16) Second motor 18 Input detection means 19 Rotation speed detection means 41 Rotary shaft of rotary pump motor 42 Cylinder block of rotary pump motor 44 Variable swash plate of rotary pump motor 45 Housing of rotary pump motor 48 Hydraulic pump (accumulation assisting means) Reference numeral 91: rotation speed correction control unit (rotation speed correction control unit) 92 first switching control unit (first switching control unit) 101 charged amount detection unit 161 rotor of the second motor 162 stator of the second motor 171 swash plate angle control unit ( Second switching control means) 172 Second switching control Part (second switching control means) 173 third switching control section (third switching control means)

Claims (12)

[Claims] An engine (1) and the engine (1)
Hydraulic pump (2) driven by the hydraulic pump (2) and an operating unit (3) driven by pressure oil discharged from the hydraulic pump (2)
a, 3b) comprising: a first electric motor (8) for reversibly transmitting torque to and from the hydraulic pump (2); and an electric motor between the first electric motor (8) and the first electric motor (8). A power storage means (10) for transferring energy; and a swing drive system (400) for rotatingly rotating the swing body (32). The first electric motor (8) is provided with a hydraulic pump (2) from the hydraulic pump (2). A power generation operation for storing the electric energy generated by receiving the torque transmission in the power storage means (10);
0) is configured to be switched to an assist operation for transmitting torque to the hydraulic pump (2) by being driven by receiving the electric energy stored in the hydraulic drive (2). Pressure accumulating means (12) for accumulating pressure energy using as a medium, the pressure accumulating means (1)
A pump motor device (4) configured to be switchable between a motor operation driven by receiving the supply of the pressure oil from 2) and a pump operation of supplying the pressure oil to the pressure accumulation means (12) to accumulate the pressure. A hydraulic drive device comprising: 2. An absorption torque detecting means (11) for detecting a required absorption torque of a hydraulic pump (2) required for driving an operation section (3a, 3b), wherein said absorption torque is When the required absorption torque detection value detected by the detection means (11) is lower than a predetermined output torque set value of the engine (1) in relation to the rotation speed of the engine (1), the electric motor (8) is operated by the surplus torque transmitted from the hydraulic pump (2), and when the required absorption torque detection value is on the higher torque side than the output torque setting value, the electric motor (8) is assisted. First switching control means (92) for switching and controlling the operation of the electric motor (8) so as to bring it into an operating state; and a required absorption torque detection value detected by the absorption torque detection means (11). When the required absorption torque detection value is higher than the force torque setting value and the required absorption torque detection value is larger than the assist limit torque value obtained by adding the maximum assist torque by the assist operation of the electric motor to the output torque of the engine (1), The rotational speed of the engine (1) is changed and corrected to a higher rotational speed such that the assist torque of the electric motor (8) becomes smaller than the maximum assist torque while maintaining the absorption horsepower based on the required absorption torque at an equal value. A hydraulic drive device comprising: engine speed correction control means (91). 3. The pump motor device (4) according to claim 1, wherein an input detecting means (18) for receiving an operation by an operator and detecting an operation amount as a rotation speed input value to the pump motor device (4). A rotation speed detecting means (19) for detecting an actual rotation speed of the motor, and a rotation speed detection value detected by the rotation speed detection means (19) is a rotation speed input value detected by the input detection means (18). When the speed is lower than the speed, the pump motor device (4) is motor-operated to increase the speed.
When the rotation speed detection value is higher than the rotation speed input value, the operation of the pump motor device (4) is switched and controlled so that the pump motor device (4) is operated to decelerate the pump. Switching control means (171, 17
2) A hydraulic drive device comprising: 4. The pump motor device (4) according to claim 3, wherein the pump motor device (4) is a variable swash plate type piston pump motor having a variable swash plate (44). A hydraulic drive device comprising: a swash plate angle control unit (171) for controlling an increase or decrease of a tilt angle of a swash plate (44) up to a maximum tilt angle on both the forward and reverse sides. 5. The power generation operation according to claim 3, wherein the electric energy generated by receiving the torque transmission from the pump motor device (4) is stored in the power storage means (10), and the electric power stored in the power storage means (10). A hydraulic drive device comprising a second electric motor (16) configured to be switched to an assist operation for transmitting torque to the pump motor device (2) by being driven by receiving energy. 6. The method according to claim 5, wherein when the rotation speed input value detected by the input detection means (18) and the rotation speed detection value detected by the rotation speed detection means (19) are equal to each other and not zero, the second one is set to a predetermined value. 2 so that the second motor (16) is switched to the assist operation state.
A hydraulic drive device comprising a third switching control means (173) for switching and controlling the operation of the electric motor (16). 7. The pump control device according to claim 6, wherein the second switching control means switches the pump motor device to the pump operation when the rotation speed input value and the rotation speed detection value are equal and not zero. A hydraulic drive device characterized by being configured as described above. 8. The switching control means (173) according to claim 6, wherein a deviation between the rotation speed input value and the rotation speed detection value is set in advance according to an inertial load applied to the pump motor device (4). A hydraulic system characterized in that the second electric motor (16) is configured to be in a cut-off state in which torque transmission with the pump motor device (4) is cut off when the second motor (16) is on the larger side than the set deviation. Drive. 9. The electric motor according to claim 6, wherein the third switching control means (173) is configured to output the second electric motor (1) when the detected rotation speed is lower than the rotation speed input value.
6) While the assist operation is performed, when the rotation speed detection value is higher than the rotation speed input value, the second
A hydraulic drive device characterized in that the operation of the second electric motor (16) is switch-controlled so that the electric motor (16) operates to generate electric power. 10. The hydraulic drive device according to claim 1, further comprising a pressure accumulation assisting means (48) for compensating a decrease in pressure energy in the pressure accumulating means (12). 11. The method according to claim 5, wherein:
In the above, the second electric motor (16) is disposed at an outer peripheral side position surrounding the rotary shaft (41) of the pump motor device (4), and the second electric motor (16) and the pump motor device (4) are integrally formed. A hydraulic drive device which is assembled. 12. The pump motor device (4) according to claim 11, wherein the cylinder block (42) that rotates integrally with the rotating shaft (41), and a housing (45) that covers the periphery of the cylinder block (42). The second electric motor (16) is provided with the cylinder block (42).
A rotor (161) attached to a position on the outer peripheral surface side of the cylinder block (42) so as to rotate integrally with the rotor (161) so as to face the rotor (161) in a radial direction about the rotation shaft (41). And a stator (162) attached to a position on the inner peripheral surface side of the housing (45).