WO2012074098A1

WO2012074098A1 - Power transmitting device for hydraulic shovel

Info

Publication number: WO2012074098A1
Application number: PCT/JP2011/077926
Authority: WO
Inventors: 緒方　永博; 健司宮川
Original assignee: ヤンマー株式会社
Priority date: 2010-12-03
Filing date: 2011-12-02
Publication date: 2012-06-07
Also published as: JP2012117349A

Abstract

A power transmitting device (20) for a hydraulic shovel (1) comprises: hydraulic pumps (a first hydraulic pump (40) and a second hydraulic pump (50)) for supplying, under pressure, operating oil to a hydraulic actuator (16); a motor generator (90) which drives the hydraulic pumps by electric power supplied thereto or which generates electricity by being driven by an engine (9); and a clutch (60) for enabling and disabling the transmission of power from the engine (9) to the hydraulic pumps and to the motor generator (90), and the hydraulic pumps are driven by the engine (9) and/or the motor generator (90). The hydraulic pumps and the motor generator (90) are arranged parallel to each other, and the hydraulic pumps, the motor generator (90), and the clutch (60) are configured integrally.

Description

Hydraulic excavator power transmission device

The present invention relates to a technique for arranging each component in a power transmission device of a hydraulic excavator that can use an engine and a motor generator as a drive source of a hydraulic pump.

Conventionally, a technology of a power transmission device that uses an engine and a motor generator as a drive source of a hydraulic pump and drives a hydraulic actuator by hydraulic oil pumped from the hydraulic pump is known. For example, as described in Patent Document 1.

The power transmission device described in Patent Document 1 is connected to a hydraulic pump that pumps hydraulic oil to a hydraulic actuator, an engine that drives the hydraulic pump, a clutch that is interposed between the engine and the hydraulic pump, and the hydraulic pump. A motor generator.
In such a power transmission device, the energy efficiency can be improved by controlling the driving of the engine and the motor generator and the connection / disconnection of the clutch according to the load of the hydraulic actuator.

JP 2001-99103 A

However, when mounting the power transmission device as described above on a hydraulic excavator, it was difficult to secure a mounting space.

In detail, as a hydraulic excavator used in construction in a small work space such as a residential area or urban area, in order to avoid contact with surrounding workers and buildings during work, The mainstream is to use a hydraulic excavator with a small amount of protrusion of the rear end of the swivel from the crawler (a so-called rear ultra-small swivel type hydraulic excavator).
In the hydraulic excavator as described above, in order to stabilize the vehicle balance during work, heavy objects such as an engine and a hydraulic pump are arranged in the vicinity of the rear end of the swivel platform on the side opposite to the work device (excavator, etc.). It is necessary to let As a result, the mounting space for the hydraulic pump (particularly, the space in the longitudinal direction of the drive shaft of the hydraulic pump) is limited, and it is difficult to ensure the mounting space.

The present invention has been made in view of the above situation, and provides a power transmission device for a hydraulic excavator that can be made compact.

The problems to be solved by the present invention are as described above. Next, means for solving the problems will be described.

That is, in the present invention, at least two hydraulic pumps for pumping hydraulic oil to the hydraulic actuator, and at least two hydraulic pumps are driven by supplying electric power, or power is generated by being driven by an engine. And a clutch for connecting and disconnecting power transmitted from the engine to the at least two hydraulic pumps and the motor generator, and the at least two hydraulic pumps are driven by the engine and / or the motor generator. A power transmission device for a hydraulic excavator to be driven, wherein the at least two hydraulic pumps and the motor generator are arranged in parallel, and the at least two hydraulic pumps, the motor generator, and the clutch are integrally configured. is there.

In the present invention, the at least two hydraulic pumps, the motor generator, the clutch, and a flywheel cover that covers the flywheel of the engine are integrally configured.

As the effects of the present invention, the following effects are obtained.

In the present invention, the power transmission device of the hydraulic excavator can be made compact, and the power transmission device can be easily mounted on the hydraulic excavator.

1 is an overall side view of a hydraulic excavator including a power transmission device according to an embodiment of the present invention. The block diagram which showed the whole structure of the power transmission device. Front sectional drawing of a power transmission case. The side view of a power transmission case. The plane schematic diagram of the hydraulic shovel which shows arrangement | positioning of an engine and a power transmission case. The schematic diagram which shows the power transmission structure of a hydraulic pump and a motor generator. (A) is a figure which shows the structure which transmits motive power via a pulley, (b) is a figure which shows the structure which transmits motive power via a gear. The schematic diagram which shows the power transmission structure of a hydraulic pump and a motor generator. (A) is a figure which shows the structure which transmits motive power via a gear, (b) is a figure which shows the structure which applied the oblique axis type axial piston pump as a hydraulic pump.

1 Hydraulic Excavator 4 Working Device 5 Crawler 5L Left Travel Motor (Hydraulic Actuator)
5R Right travel motor (hydraulic actuator)
6 swivel base 7 swivel motor (hydraulic actuator)
9 Engine 9b Flywheel 13 Boom cylinder (hydraulic actuator)
14 Arm cylinder (hydraulic actuator)
15 Bucket cylinder (hydraulic actuator)
16 Hydraulic actuator 20 Power transmission device 30 Power transmission case 31 Flywheel cover 40 First hydraulic pump (hydraulic pump)
50 Second hydraulic pump (hydraulic pump)
60 clutch 90 motor generator

In the following description, the arrow L direction in the figure is defined as the left direction, the arrow U direction is defined as the upward direction, and the arrow F direction is defined as the forward direction.

First, the hydraulic excavator 1 including the power transmission device 20 according to the first embodiment of the present invention will be described with reference to FIG.

The hydraulic excavator 1 includes a traveling device 2, a turning device 3, and a working device 4.

The traveling device 2 includes a pair of left and

right crawlers

5, 5, a left traveling motor 5L, a right traveling motor 5R, and the like.
The traveling device 2 can drive the hydraulic excavator 1 forward and backward by driving the crawler 5 on the left side of the body with the left traveling motor 5L and the crawler 5 on the right side of the body with the right traveling motor 5R.

The swivel device 3 constitutes the vehicle body of the excavator 1, and includes a swivel base 6, a swivel motor 7, a control unit 8, an engine 9, and the like.
The swivel base 6 is disposed above the travel device 2 and is supported by the travel device 2 so as to be capable of swiveling. The turning device 3 can turn the turntable 6 with respect to the traveling device 2 by driving the turning motor 7. In addition, on the swivel base 6, a control unit 8 including various operation tools, an engine 9 serving as a power source, and the like are arranged. A flywheel 9b is fixed to the output shaft 9a of the engine 9, and power can be taken out from a connecting shaft 9c connected to the flywheel 9b (see FIG. 2).
In addition, although the engine 9 which concerns on this embodiment shall be a diesel engine, this invention is not limited to this, A gasoline engine may be sufficient.

The working device 4 includes a boom 10, an arm 11, a bucket 12, a boom cylinder 13, an arm cylinder 14, a bucket cylinder 15, and the like.
One end of the boom 10 is pivotally supported by the front portion of the swivel base 6 and is rotated by a boom cylinder 13 that is extended and retracted. More specifically, when the boom cylinder 13 is extended, the boom 10 is rotated upward, and when the boom cylinder 13 is contracted, the boom 10 is rotated downward.
One end of the arm 11 is pivotally supported by the other end of the boom 10 and is rotated by an arm cylinder 14 that is extended and retracted. More specifically, when the arm cylinder 14 is extended, the arm 11 is rotated downward (the direction in which the other end of the arm 11 is close to the boom 10), and when the arm cylinder 14 is contracted, the arm 11 is upward. (The other end side of the arm 11 is rotated away from the boom 10).
One end of the bucket 12 is supported by the other end of the arm 11 and is rotated by a bucket cylinder 15 that is driven to extend and retract. More specifically, when the bucket cylinder 15 is extended, the bucket 12 is rotated downward (a direction in which the other end of the bucket 12 is close to the arm 11), and when the bucket cylinder 15 is contracted, the bucket 12 is upward. (The other end side of the bucket 12 is rotated away from the arm 11).
As described above, the working device 4 has a multi-joint structure that excavates earth and sand using the bucket 12.

Hereinafter, the boom cylinder 13, the arm cylinder 14, the bucket cylinder 15, the left traveling motor 5L, the right traveling motor 5R, and the turning motor 7 are collectively referred to as a hydraulic actuator 16.

The working device provided in the excavator 1 according to the present embodiment is the working device 4 that has the bucket 12 and performs excavation work. However, the working device is not limited to this. For example, the working device has a hydraulic breaker and is crushed. It may be a working device that performs work.

Hereinafter, a power transmission device 20 according to an embodiment of the present invention will be described with reference to FIG.

The power transmission device 20 transmits power from a drive source and drives various actuators.
The power transmission device 20 includes a first hydraulic pump 40, a second hydraulic pump 50, a clutch 60, a control valve 70, an operation unit 80, a motor generator 90, a battery 100, an inverter 110, a cell motor 120, an absorption horsepower detection unit 130, an operation state. A detection unit 140, a charge state detection unit 150, an engine speed setting unit 160, an idle stop selection unit 170, an engine controller unit 180, a main controller 190, and the like are provided.

The first hydraulic pump 40 is an embodiment of the hydraulic pump according to the present invention, and is rotationally driven by the transmitted power to discharge hydraulic oil. The first hydraulic pump 40 is a variable displacement pump that can change the discharge amount of hydraulic oil by changing the inclination angle of the movable swash plate 46. The inclination angle of the movable swash plate 46 can be changed by an actuator (not shown) or manual operation. The first hydraulic pump 40 is rotationally driven by power input from an input shaft 41 provided in the first hydraulic pump 40. A gear 42 and a pulley 48 are fixed to the input shaft 41. One end of an oil passage 49 is connected to the discharge port of the first hydraulic pump 40.

The second hydraulic pump 50 is an embodiment of the hydraulic pump according to the present invention, and is rotationally driven by the transmitted power to discharge hydraulic oil. The second hydraulic pump 50 is a variable displacement pump that can change the discharge amount of hydraulic oil by changing the inclination angle of the movable swash plate 56. The inclination angle of the movable swash plate 56 can be changed by an actuator (not shown) or manual operation. The second hydraulic pump 50 is rotationally driven by power input from an input shaft 51 provided in the second hydraulic pump 50. A gear 52 is fixed to the input shaft 51. The gear 52 is meshed with a gear 42 fixed to the input shaft 41 of the first hydraulic pump 40. One end of an oil passage 59 is connected to the discharge port of the second hydraulic pump 50.

Further, the number of teeth of the gear 52 is set to be the same as the number of teeth of the gear 42. Thus, when the gear 52 and the gear 42 rotate while meshing with each other, the rotation speeds of the gear 52 and the gear 42 are the same. That is, the first hydraulic pump 40 and the second hydraulic pump 50 rotate at the same rotational speed.

The clutch 60 is interposed between the connecting shaft 9 c of the engine 9 and the input shaft 41 of the first hydraulic pump 40, and connects and disconnects power transmitted between the connecting shaft 9 c and the input shaft 41. When the clutch 60 is connected, the connecting shaft 9c and the input shaft 41 are connected. In this case, the connecting shaft 9c and the input shaft 41 can rotate at the same rotational speed, and as a result, the engine 9, and the first hydraulic pump 40 and the second hydraulic pump 50 can rotate at the same rotational speed. When the clutch 60 is disengaged, the connection between the connecting shaft 9c and the input shaft 41 is released, and even if the connecting shaft 9c of the engine 9 rotates, the rotational power is not transmitted to the input shaft 41.
As the clutch 60, various clutches such as a hydraulic clutch and an electromagnetic clutch can be applied.

The control valve 70 is for appropriately switching the direction and flow rate of hydraulic oil supplied from the first hydraulic pump 40 and the second hydraulic pump 50. The control valve 70 appropriately includes a direction switching valve, a pressure compensation valve, and the like.
The other end of the oil passage 49 is connected to the control valve 70, and hydraulic oil discharged from the first hydraulic pump 40 is supplied to the control valve 70 through the oil passage 49.
The other end of the oil passage 59 is connected to the control valve 70, and hydraulic oil discharged from the second hydraulic pump 50 is supplied to the control valve 70 through the oil passage 59.
The hydraulic oil pumped from the first hydraulic pump 40 and the second hydraulic pump 50 is appropriately supplied to the hydraulic actuator 16 (boom cylinder 13, arm cylinder 14, etc.) via the control valve 70. The hydraulic actuator 16 is driven by the supplied hydraulic oil.

The hydraulic actuator according to the present invention is not limited to the hydraulic actuator 16 (boom cylinder 13, arm cylinder 14, etc.), and may be a hydraulic actuator driven by hydraulic oil.

The operating means 80 is for switching the direction and flow rate of the hydraulic oil supplied to the hydraulic actuator 16 via the control valve 70. When the operation means 80 is operated by an operator, the operation signal (electric signal) is transmitted to the control valve 70. Based on the signal, various valves (such as a directional switching valve) provided in the control valve 70 are switched. As a result, a desired amount of hydraulic fluid can be supplied to the hydraulic actuator 16 desired by the operator.

In addition, although the operation means 80 which concerns on this embodiment shall operate the control valve 70 with an electrical signal, this invention is not limited to this. That is, it may be hydraulic operating means that applies a pilot pressure to the control valve 70 based on an operator's operation and operates the control valve 70 with the pilot pressure.
When hydraulic operating means is used as the operating means 80 as described above, the hydraulic pressure can be supplied to the hydraulic operating means even when the engine 9 is stopped by idle stop control described later. A hydraulic pump for supplying hydraulic oil to the operation means of the type and an electric motor for driving the hydraulic pump are separately provided.

The motor generator 90 is rotationally driven as an electric motor to generate power when electric power is supplied, and generates electric power as a generator when power is supplied. The motor generator 90 includes an input / output shaft 91, and a pulley 92 is fixed to the input / output shaft 91. A belt 93 is wound around the pulley 92 and the pulley 48 so that power can be transmitted between the pulley 92 and the pulley 48.
The motor generator 90 can rotationally drive the input / output shaft 91 when electric power is supplied.
The motor generator 90 can generate electric power when power is transmitted and the input / output shaft 91 is rotationally driven.

The battery 100 is a secondary battery that can store and discharge electric power supplied to the motor generator 90 and other electric devices.

The inverter 110 supplies electric power from the battery 100 to the motor generator 90 or enables electric power from the motor generator 90 to be supplied to the battery 100.
The inverter 110 includes a circuit that converts direct current into alternating current (inverter circuit) and a circuit that converts alternating current into direct current (converter circuit), and selects either one of the inverter circuit and the converter circuit or both It is possible not to.

When the inverter circuit is selected, the inverter 110 converts the DC power supplied from the battery 100 into AC and supplies it to the motor generator 90. As described above, by allowing the inverter 110 to supply the electric power from the battery 100 to the motor generator 90, the motor generator 90 rotates the input / output shaft 91. That is, in this case, the motor generator 90 can be used as an electric motor. In this case, the supply of electric power from motor generator 90 to battery 100 is interrupted. Hereinafter, a state in which the motor generator 90 rotationally drives the input / output shaft 91 is referred to as a “driving state”.

When the converter circuit is selected, the inverter 110 converts AC power supplied from the motor generator 90 into DC and stores the power in the battery 100. In this way, by allowing the inverter 110 to supply power from the motor generator 90 to the battery 100, the motor generator 90 generates power by the power from the engine 9 and stores (charges) the power in the battery 100. )be able to. That is, in this case, the motor generator 90 can be used as a generator. In this case, the supply of power from battery 100 to motor generator 90 is interrupted. Hereinafter, a state in which the motor generator 90 charges the battery 100 is referred to as a “power generation state”.

When neither the inverter circuit nor the converter circuit is selected, the inverter 110 neither supplies power to the motor generator 90 nor supplies power to the battery 100. As described above, since power is not supplied to the motor generator 90, the motor generator 90 does not rotate the input / output shaft 91. Even if the input / output shaft 91 of the motor generator 90 is driven to rotate, the battery 100 is not charged because the power is not supplied to the battery 100, and the input / output shaft 91 of the motor generator 90 is rotated at this time. The resistance is smaller than the rotational resistance of the input / output shaft 91 in the power generation state. Hereinafter, a state in which the motor generator 90 neither rotates the input / output shaft 91 nor charges the battery 100 is referred to as a “neutral state”.

The cell motor 120 is an electric motor for starting the engine 9. The cell motor 120 is driven by electric power supplied from the battery 100.

The absorption horsepower detection means 130 is for detecting the absorption horsepower Lp by the first hydraulic pump 40 and the second hydraulic pump 50. Here, the absorption horsepower Lp refers to horsepower required for the first hydraulic pump 40 and the second hydraulic pump 50 to drive. The absorption horsepower detection means 130 includes a first pressure detection means 131, a second pressure detection means 132, a first volume detection means 133, a second volume detection means 134, and a pump rotation speed detection means 135.

The first pressure detecting means 131 is a sensor that detects the discharge pressure P1 of the first hydraulic pump 40. The first pressure detecting means 131 is connected to the middle portion of the oil passage 49 and can detect the discharge pressure P1 of the first hydraulic pump 40 by detecting the pressure in the oil passage 49.

The second pressure detection means 132 is a sensor that detects the discharge pressure P2 of the second hydraulic pump 50. The second pressure detection means 132 is connected to the middle part of the oil passage 59, and by detecting the pressure in the oil passage 59, the discharge pressure P2 of the second hydraulic pump 50 can be detected.

The first volume detection means 133 is for detecting the displacement volume q1 of the first hydraulic pump 40. The first volume detection means 133 is a sensor that detects the inclination angle of the movable swash plate 46 of the first hydraulic pump 40. Based on the inclination angle of the movable swash plate 46, a displacement q1 of the first hydraulic pump 40 is calculated by a main controller 190 described later.

The second volume detection means 134 is for detecting the displacement volume q2 of the second hydraulic pump 50. The second volume detection means 134 is a sensor that detects the inclination angle of the movable swash plate 56 of the second hydraulic pump 50. Based on the inclination angle of the movable swash plate 56, a displacement volume q2 of the second hydraulic pump 50 is calculated by a main controller 190 described later.

The pump rotation speed detection means 135 is a sensor that detects the rotation speed Np of the first hydraulic pump 40 and the second hydraulic pump 50. The pump rotational speed detection means 135 can detect the rotational speed Np of the second hydraulic pump 50 by detecting the rotational speed of the gear 52 fixed to the input shaft 51 of the second hydraulic pump 50. Further, since the second hydraulic pump 50 and the first hydraulic pump 40 have the same rotational speed Np, the pump rotational speed detection means 135 detects the rotational speed Np of the second hydraulic pump 50, thereby simultaneously producing the first hydraulic pressure. The rotational speed Np of the pump 40 is also detected.

The operation state detection unit 140 is a sensor that detects whether or not the operation unit 80 is being operated. The operation state detection means 140 is composed of a potentiometer or the like, and can detect that the operation means 80 has been operated by the operator.

The operation state detection unit 140 according to the present embodiment directly detects that the operation unit 80 is operated by a potentiometer or the like, but the present invention is not limited to this. That is, when the operation means 80 is a hydraulic type, it may be configured to detect that the operation means 80 is operated by detecting a pilot pressure for operating the control valve 70 with a pressure switch or the like.
When the operation means 80 is hydraulic as described above, the hydraulic operation is performed so that the hydraulic oil can be supplied to the hydraulic operation means even when the engine 9 is stopped by idle stop control described later. A hydraulic pump for supplying hydraulic oil to the means and an electric motor for driving the hydraulic pump are separately provided.

The charge state detection means 150 detects the charge amount (remaining amount) C of the battery 100. The charge state detection means 150 can detect information (for example, voltage, specific gravity of the battery fluid, etc.) indicating the charge amount (remaining amount) C of the battery 100.

The engine speed setting means 160 sets the speed of the engine 9. The engine speed setting means 160 is constituted by a dial switch and can be operated by an operator. The operation amount of the engine speed setting means 160 can be detected by a sensor (not shown) provided in the engine speed setting means 160.
The engine speed setting means 160 is not limited to a dial switch, and may be a lever, a pedal, or the like.

The idle stop selection means 170 is for selecting whether or not to perform idle stop control which will be described later. The idle stop selection means 170 is constituted by a dial switch and can be operated by an operator. The idle stop selection means 170 switches to an “OFF” position where idle stop control is not performed, an “ON” position where idle stop control is performed, or a “motor drive” position where the engine 9 is stopped and only the motor generator 90 is driven. Can do. The position of the idle stop selection unit 170 can be detected by a sensor (not shown) provided in the idle stop selection unit 170.

The engine controller unit (hereinafter simply referred to as “ECU”) 180 is for controlling the operation of the engine 9 based on various signals and programs. Specifically, ECU 180 may have a configuration in which a CPU, ROM, RAM, HDD, or the like is connected by a bus, or may be configured by a one-chip LSI or the like.

ECU 180 is connected to an engine speed detecting means (not shown) for detecting the speed Ne of the engine 9 and can acquire a detection signal of the speed Ne of the engine 9 by the engine speed detecting means.

The ECU 180 is connected to the cell motor 120, transmits a control signal to the cell motor 120, and rotates the crankshaft of the engine 9 by the cell motor 120 to start the engine 9.
The ECU 180 is connected to a speed control device (not shown) for adjusting the fuel injection amount of the engine 9, transmits a control signal to the speed control device, and adjusts the fuel injection amount of the engine 9 to adjust the rotational speed Ne. The engine 9 can be stopped by changing the torque characteristics or stopping the fuel supply of the engine 9.

The main controller 190 transmits control signals to the clutch 60, the inverter 110, and the ECU 180 based on various signals and programs. Specifically, the main controller 190 may be configured such that a CPU, a ROM, a RAM, an HDD, and the like are connected by a bus, or may be configured by a one-chip LSI or the like.

The main controller 190 is connected to the first pressure detection means 131, and can acquire a detection signal of the discharge pressure P1 of the first hydraulic pump 40 by the first pressure detection means 131.
The main controller 190 is connected to the second pressure detection means 132, and can acquire a detection signal of the discharge pressure P2 of the second hydraulic pump 50 by the second pressure detection means 132.
The main controller 190 is connected to the first volume detection means 133 and can acquire a detection signal of the inclination angle of the movable swash plate 46 of the first hydraulic pump 40 by the first volume detection means 133. The main controller 190 stores a map showing the relationship between the inclination angle of the movable swash plate 46 and the displacement volume q1 of the first hydraulic pump 40. The main controller 190 calculates the displacement volume q1 of the first hydraulic pump 40 based on the detection signal of the inclination angle of the movable swash plate 46.
The main controller 190 is connected to the second volume detection unit 134 and can acquire a detection signal of the tilt angle of the movable swash plate 56 of the second hydraulic pump 50 by the second volume detection unit 134. The main controller 190 stores a map indicating the relationship between the tilt angle of the movable swash plate 56 and the displacement volume q2 of the second hydraulic pump 50. The main controller 190 calculates the displacement q2 of the second hydraulic pump 50 based on the detection signal of the inclination angle of the movable swash plate 56.
The main controller 190 is connected to the pump rotation speed detection means 135, and can acquire a detection signal of the rotation speed Np of the first hydraulic pump 40 and the second hydraulic pump 50 by the pump rotation speed detection means 135.

The main controller 190 calculates the absorption horsepower Lp by the first hydraulic pump 40 and the second hydraulic pump 50 based on the discharge pressure P1, the discharge pressure P2, the displacement volume q1, the displacement volume q2, and the rotation speed Np. The absorption horsepower Lp is calculated using an equation of Lp = K × ((P1 × q1 × Np) + (P2 × q2 × Np)) (K is a constant).

The main controller 190 is connected to the operation state detection unit 140 and can acquire a detection signal indicating that the operation unit 80 by the operation state detection unit 140 has been operated.
The main controller 190 is connected to the charge state detection unit 150 and can acquire a detection signal of the charge amount (remaining amount) C of the battery 100 by the charge state detection unit 150.

The main controller 190 is connected to the ECU 180, and can acquire a detection signal of the rotational speed Ne of the engine 9 by the ECU 180 (more specifically, an engine rotational speed detection means connected to the ECU 180). Further, the main controller 190 can transmit control signals to the ECU 180 to start or stop the engine 9 and to instruct the target rotational speed of the engine 9.

The main controller 190 is connected to a sensor provided in the engine speed setting means 160, and can acquire a detection signal of the operation amount of the engine speed setting means 160 by the sensor.
The main controller 190 is connected to a sensor provided in the idle stop selection unit 170, and can acquire a detection signal of the position of the idle stop selection unit 170 by the sensor.

The main controller 190 is connected to the clutch 60 and can transmit a control signal to the clutch 60 to connect and disconnect the clutch 60.
The main controller 190 is connected to the inverter 110 and can transmit to the inverter 110 a control signal indicating that either one of the inverter circuit or the converter circuit is selected or neither is selected.

Hereinafter, a basic operation mode of the power transmission device 20 configured as described above will be described.

When a key switch or the like (not shown) is operated and a signal to start the engine 9 is transmitted to the main controller 190, the main controller 190 transmits a control signal to start the engine 9 to the ECU 180. The ECU 180 that has received the control signal transmits the control signal to the cell motor 120 and starts the engine 9.

Further, when a key switch or the like (not shown) is operated and a signal to stop the engine 9 is transmitted to the main controller 190, the main controller 190 transmits a control signal to stop the engine 9 to the ECU 180. The ECU 180 that has received the control signal transmits the control signal to the speed governor and stops the engine 9.

When the engine 9 is started, the main controller 190 determines the target rotational speed of the engine 9 based on the operation amount of the engine rotational speed setting means 160. The main controller 190 transmits the target rotational speed of the engine 9 to the ECU 180 as a control signal. The ECU 180 that has received the control signal transmits a control signal to the speed governor, and adjusts the rotational speed Ne of the engine 9 so that the rotational speed Ne of the engine 9 becomes the target rotational speed.

When the engine 9 is started (driven) and the clutch 60 is connected, the power of the engine 9 is transmitted to the first hydraulic pump 40 via the connecting shaft 9c, the clutch 60, and the input shaft 41. The power from the engine 9 is also transmitted to the second hydraulic pump 50 via the gear 42, the gear 52 and the input shaft 51. As a result, the first hydraulic pump 40 and the second hydraulic pump 50 rotate at the same rotational speed Np.

When the first hydraulic pump 40 and the second hydraulic pump 50 are driven (rotated), hydraulic oil is discharged from the first hydraulic pump 40 and the second hydraulic pump 50. The hydraulic oil is supplied to the control valve 70 through the oil passage 49 and the oil passage 59. The control valve 70 supplies hydraulic oil to the hydraulic actuator 16 desired by the operator based on an operation signal from the operation means 80.

On the other hand, when the control signal for selecting the inverter circuit is transmitted to the inverter 110 by the main controller 190, the motor generator 90 is switched to the driving state. In this case, the motor generator 90 rotates the input / output shaft 91 with the electric power of the battery 100 to generate power. The power is transmitted to the first hydraulic pump 40 through the input / output shaft 91, the pulley 92, the belt 93, the pulley 48, and the input shaft 41, and is transmitted through the gear 42, the gear 52, and the input shaft 51. Two hydraulic pumps 50 are transmitted. That is, in this case, the first hydraulic pump 40 and the second hydraulic pump 50 can be driven by the power from the motor generator 90 in addition to the power from the engine 9.

When the control signal for selecting the converter circuit is transmitted to the inverter 110 by the main controller 190, the motor generator 90 is switched to the power generation state. In this case, the motor generator 90 is rotationally driven by the power from the engine 9 transmitted via the belt 93, the pulley 92, and the input / output shaft 91, and generates electric power. The electric power is stored in the battery 100 via the inverter 110. In other words, in this case, the first hydraulic pump 40 and the second hydraulic pump 50 are driven by the power from the engine 9, and the motor generator 90 is rotationally driven to store electric power in the battery 100.

Further, when a control signal indicating that neither the inverter circuit nor the converter circuit is selected by the main controller 190 is transmitted to the inverter 110, the motor generator 90 is switched to the neutral state. In this case, the motor generator 90 is rotationally driven by the power from the engine 9 transmitted via the belt 93, the pulley 92, and the input / output shaft 91, but does not charge the battery 100. For this reason, the rotational resistance of the input / output shaft 91 of the motor generator 90 is smaller than that in the power generation state.

In the power transmission device 20 configured as described above, for example, the following control is possible.

When the absorption horsepower Lp is larger than a preset value, the main controller 190 switches the motor generator 90 to the driving state. Thus, the first hydraulic pump 40 and the second hydraulic pump 50 are driven by the motor generator 90 in addition to the engine 9. That is, the motor generator 90 can assist in driving the first hydraulic pump 40 and the second hydraulic pump 50.

Even if the absorption horsepower Lp is larger than a preset value, if the charge amount C of the battery 100 is smaller than a preset value, the main controller 190 switches the motor generator 90 to a neutral state. Thereby, overdischarge of the battery 100 can be prevented.

On the other hand, when the absorption horsepower Lp is smaller than a preset value and the charge amount C of the battery 100 is smaller than a preset value, the main controller 190 switches the motor generator 90 to the power generation state. As a result, the battery 100 can be charged using a margin of the output of the engine 9.

In the power transmission device 20 configured as described above, for example, the following control (so-called idle stop control) is possible.

When the operating means 80 has not been operated continuously for a certain time, the main controller 190 stops the engine 9, disconnects the clutch 60, and switches the motor generator 90 to the neutral state. As a result, wasteful fuel and power consumption can be suppressed.

After that, when the operation means 80 is operated, the main controller 190 switches the motor generator 90 to the driving state. Accordingly, the first hydraulic pump 40 and the second hydraulic pump 50 can be driven promptly by the motor generator 90 (electric motor) generally having a high low-speed torque.

Further, after this, when the absorption horsepower Lp becomes larger than a preset value, the main controller 190 starts the engine 9, connects the clutch 60, and switches the motor generator 90 to the neutral state. Thereby, when the absorption horsepower Lp is large, the first hydraulic pump 40 and the second hydraulic pump 50 can be driven by the engine 9.

Hereinafter, the configuration of the first hydraulic pump 40, the second hydraulic pump 50, the clutch 60, and the motor generator 90 will be described in detail with reference to FIG. 3 and FIG.

The first hydraulic pump 40, the second hydraulic pump 50, the clutch 60, and the motor generator 90 are supported by the power transmission case 30.
The power transmission case 30 includes a flywheel cover 31, a connecting plate 32, a pump case 33, and the like.

The flywheel cover 31 is a member that covers the flywheel 9b of the engine 9 from the right side. The flywheel cover 31 includes a substantially truncated cone-shaped cover portion 31a in a front sectional view and a substantially rectangular parallelepiped body portion 31b integrally formed on the upper right end of the cover portion 31a. The inside of the cover part 31a is formed so as to open toward the left, and the inside of the main body part 31b is formed so as to open toward the right. A through hole 31c that connects the inside of the cover portion 31a and the inside of the main body portion 31b is formed in the substantially right and left central portion of the flywheel cover 31 (more specifically, the substantially central portion of the cover portion 31a in the vertical and horizontal directions). The

The connecting plate 32 is a substantially rectangular plate-like member. The connecting plate 32 is disposed with the plate surface directed in the left-right direction. The connecting plate 32 is formed with a pair of upper and lower through

holes

32a and 32b penetrating the plate surface in the left-right direction. The connecting plate 32 is fixed to the right end of the main body 31 b of the flywheel cover 31.

The pump case 33 is a substantially rectangular parallelepiped member. The inside of the pump case 33 is formed so as to open toward the left. A through-hole 33 a that communicates the inside and the outside of the pump case 33 is formed in the lower portion of the right side surface of the pump case 33. The pump case 33 is fixed to the right end of the connecting plate 32.

The clutch 60 is disposed in the cover portion 31a of the flywheel cover 31 (specifically, on the right side surface in the cover portion 31a and around the through hole 31c).

The first hydraulic pump 40 includes an input shaft 41, a gear 42, a cylinder block 43, a piston 44, a shoe 45, a movable swash plate 46, a valve plate 47, and the like.

The input shaft 41 is arranged with the axial direction directed in the left-right direction, and is inserted into the through hole 31 c of the flywheel cover 31, the through hole 32 b of the connecting plate 32, and the through hole 33 a of the pump case 33. At this time, an oil seal 31d, an oil seal 32d, and an oil seal 33b are provided between the through hole 31c, the through hole 32b, and the through hole 33a and the input shaft 41, respectively. The input shaft 41 is rotatably supported by the pump case 33 via a bearing 41a. One end (left end) of the input shaft 41 is connected to the clutch 60. The other end (right end) of the input shaft 41 protrudes to the right of the pump case 33, and a pulley 48 is fixed to the protruding portion.

The gear 42 is spline-fitted to the input shaft 41 inside the main body 31 b of the flywheel cover 31 and is supported by the input shaft 41 so as not to be relatively rotatable. The gear 42 is rotatably supported by the main body 31b of the flywheel cover 31 via the bearing 42a and the bearing 42b.

The cylinder block 43 is a substantially cylindrical member, and is arranged with the axial direction facing the left-right direction. The cylinder block 43 is spline-fitted to the input shaft 41 inside the pump case 33 and is supported by the input shaft 41 so as not to be relatively rotatable. A plurality of

cylinders

43a, 43a,... Are formed on the same circumference around the axis of the cylinder block 43.

The piston 44 performs suction and discharge of hydraulic oil by sliding in the cylinder 43a. A plurality of pistons 44 are provided, and right end sides of the plurality of

pistons

44, 44... Are slidably inserted into the

cylinders

43a, 43a,.

The shoe 45 restrains the sliding position of the piston 44 to the movable swash plate 46 side. A plurality of shoes 45 are provided, and the plurality of shoes 45... Are connected to the left ends of the pistons 44. The

shoes

45, 45... Are held by a plate (not shown) so as not to be separated from the movable swash plate 46 and to be slidable on the movable swash plate 46.

The movable swash plate 46 is for changing the sliding amount of the pistons 44. The movable swash plate 46 is fitted on the input shaft 41 on the left side of the cylinder block 43. By changing the inclination angle of the movable swash plate 46, the sliding amount of the

pistons

44, 44... Relative to the

cylinders

43a, 43a.

The valve plate 47 guides hydraulic oil sucked and discharged by the

pistons

44, 44. The valve plate 47 is a substantially disk-shaped member, and is fitted on the input shaft 41 in a state where the valve plate 47 is in contact with the right end of the cylinder block 43. The valve plate 47 is formed with an oil passage for appropriately guiding hydraulic oil.

In the first hydraulic pump 40 configured as described above, when the input shaft 41 rotates, the cylinder block 43 rotates together with the input shaft 41. When the cylinder block 43 rotates, the

pistons

44, 44, ... inserted into the

cylinders

43a, 43a, ... of the cylinder block 43 slide on the movable swash plate 46 via the

shoes

45, 45 ... While rotating around the input shaft 41.

When the movable swash plate 46 tilts in this state, the

pistons

44, 44... Slide in the

cylinders

43a, 43a. The hydraulic oil is drawn into the

cylinders

43a, 43a,... Through the valve plate 47 or discharged from the

cylinders

43a, 43a,. The

The second hydraulic pump 50 includes an input shaft 51, a gear 52, a cylinder block 53, a piston 54, a shoe 55, a movable swash plate 56, a valve plate 57, and the like.
Since the second hydraulic pump 50 has substantially the same configuration as that of the first hydraulic pump 40, the following description will be made on portions of the configuration of the second hydraulic pump 50 that are different from the first hydraulic pump 40.

The input shaft 51 is disposed right above the input shaft 41 of the first hydraulic pump 40 with the axial direction directed in the left-right direction, and is inserted into the through hole 32a of the connecting plate 32. At this time, an oil seal 32 c is provided between the through hole 32 a and the input shaft 51. The input shaft 51 is rotatably supported by the pump case 33 via a bearing 51a.

The gear 52 is spline-fitted to the input shaft 51 inside the main body 31 b of the flywheel cover 31 and is supported by the input shaft 51 so as not to be relatively rotatable. The gear 52 is rotatably supported by the main body 31b of the flywheel cover 31 via a bearing 52a and a bearing 52b. The gear 52 is meshed with the gear 42 of the first hydraulic pump 40.

The second hydraulic pump 50 is disposed in parallel with the first hydraulic pump 40. That is, the input shaft 51 of the second hydraulic pump 50 is disposed in parallel with the input shaft 41 of the first hydraulic pump 40, and at least a part of the second hydraulic pump 50 overlaps the first hydraulic pump 40 in the left-right direction. Be placed.
In the present embodiment, each member of the second hydraulic pump 50 is disposed so as to be in the same position as each member of the first hydraulic pump 40 in the left-right direction. Specifically, the gear 52 is in the same position in the left-right direction as the gear 42, the cylinder block 53 is in the cylinder block 43, the movable swash plate 56 is in the movable swash plate 46, and the valve plate 57 is in the same position in the left-right direction. Has been placed.

In the second hydraulic pump 50 configured as described above, when the rotation of the input shaft 41 is transmitted to the input shaft 51 via the gear 42 and the gear 52, the cylinder block 53 rotates together with the input shaft 51. When the cylinder block 53 rotates, the

pistons

54, 54, ... inserted into the

cylinders

53a, 53a, ... of the cylinder block 53 slide on the movable swash plate 56 via the

shoes

55, 55, ... While rotating around the input shaft 51.

When the movable swash plate 56 tilts in this state, the

pistons

54, 54,... Slide in the

cylinders

53a, 53a,. The hydraulic fluid is drawn into the

cylinders

53a, 53a,... Through the valve plate 57 or discharged from the

cylinders

53a, 53a,. The

The motor generator 90 is disposed so that the axial direction of the input / output shaft 91 is directed to the left and right, and the input / output shaft 91 is directed to the right. The motor generator 90 is fixed to the lower part of the pump case 33 so that the input / output shaft 91 is positioned directly below the input shaft 41 of the first hydraulic pump 40. Thus, the motor generator 90 is below the pump case 33, the connecting plate 32, and the flywheel cover 31 (specifically, the main body portion 31b), and the flywheel cover 31 (specifically, the cover portion 31a). Located in the lower right space. The input / output shaft 91 of the motor generator 90 extends so as to protrude rightward from the right side surface of the pump case 33, and a pulley 92 is fixed to the protruding portion. A belt 93 is wound between the pulley 92 and the pulley 48.

The motor generator 90 is arranged in parallel with the first hydraulic pump 40 and the second hydraulic pump 50. That is, the input / output shaft 91 of the motor generator 90 is arranged in parallel with the input shaft 41 of the first hydraulic pump 40 and the input shaft 51 of the second hydraulic pump 50, and at least a part of the motor generator 90 is the first hydraulic pressure in the left-right direction. It arrange | positions so that the pump 40 and the 2nd hydraulic pump 50 may overlap.
In the present embodiment, the motor generator 90 is disposed so as to be substantially at the same position as the first hydraulic pump 40 and the second hydraulic pump 50 in the left-right direction. Specifically, the motor generator 90 is arranged so that the left end of the motor generator 90 is in the same position in the left-right direction, and the right end of the motor generator 90 is in the left-right direction.

As described above, the first hydraulic pump 40, the second hydraulic pump 50, the clutch 60, and the motor generator 90 are integrally configured by being supported by the power transmission case 30.

Hereinafter, the arrangement when the power transmission device 20 configured as described above is mounted on the excavator 1 will be described with reference to FIGS.

As shown in FIG. 5, in the hydraulic excavator 1, heavy objects such as the engine 9, the first hydraulic pump 40, and the second hydraulic pump 50 are used to work on the swivel 6 in order to stabilize the vehicle balance during the work. Usually, it is arranged on the opposite side of the device 4 (near the rear end of the swivel base 6).

In this case, in a rear ultra-small turning type hydraulic excavator or the like, the swivel base 6 is usually configured in a substantially circular shape in plan view, and thus the mounting space for the engine 9 and the first hydraulic pump 40 and the like is limited. Will be. More specifically, the space in the axial direction (left-right direction in FIG. 5) of the input shaft 41 of the first hydraulic pump 40 is limited.

In the present embodiment, as shown in FIGS. 3 and 4, the first hydraulic pump 40, the second hydraulic pump 50, and the motor generator 90 are arranged in parallel in the vertical direction, and the first hydraulic pump 40, second The hydraulic pump 50, the clutch 60, and the motor generator 90 are integrally configured. The second hydraulic pump 50 is disposed above the first hydraulic pump 40 and the motor generator 90 is disposed below the first hydraulic pump 40 to balance the left and right, as well as the flywheel cover 31 and the connecting plate 32. The motor generator 90 is integrally fixed to the lower surface of the pump case 33 in the right lower space of the power transmission case 30 constituted by the pump case 33. As a result, the motor generator 90 enters the projected area of the power transmission case 30 in a plan view and substantially enters the projected area of the cover portion 31a in a side view. In this way, the first hydraulic pump 40, the second hydraulic pump 50, the clutch 60, and the motor generator 90 can be made compact, and as a result, the power transmission device 20 can be made compact.
Therefore, the power transmission device 20 according to this embodiment can be easily mounted on the hydraulic excavator 1 in which the mounting space for the engine 9, the first hydraulic pump 40, and the like is limited as described above.

As described above, the power transmission device 20 of the hydraulic excavator 1 according to the present embodiment supplies the hydraulic pumps (the first hydraulic pump 40 and the second hydraulic pump 50) for pumping hydraulic oil to the hydraulic actuator 16, and supplies power. A motor generator 90 for driving the hydraulic pump by being driven or generating electric power by being driven by the engine 9, and a clutch 60 for connecting / disconnecting power transmitted from the engine 9 to the hydraulic pump and the motor generator 90, A power transmission device 20 of a hydraulic excavator 1 that drives the hydraulic pump by an engine 9 and / or a motor generator 90, wherein the hydraulic pump and the motor generator 90 are arranged in parallel, and the hydraulic pump and the motor generator 90 and the clutch 60 are integrally formed.
With this configuration, the power transmission device 20 of the hydraulic excavator 1 can be made compact, and the power transmission device 20 can be easily mounted on the hydraulic excavator 1.
Further, by integrally configuring the hydraulic pump, the motor generator 90, and the clutch 60, it is possible to reduce the number of steps for assembling the power transmission device 20 to the hydraulic excavator 1.

Further, the power transmission device 20 according to the present embodiment is configured integrally with the hydraulic pump, the motor generator 90, the clutch 60, and the flywheel cover 31 that covers the flywheel 9b of the engine 9.
With this configuration, the power transmission device 20 of the hydraulic excavator 1 can be made compact, and the power transmission device 20 can be easily mounted on the hydraulic excavator 1.
Further, by integrally configuring the hydraulic pump, the motor generator 90, the clutch 60, and the flywheel cover 31, the number of steps for assembling the power transmission device 20 to the hydraulic excavator 1 can be reduced.

Moreover, the power transmission device 20 according to the present embodiment is
The hydraulic pump and motor generator 90 are arranged in a line in the vertical direction.
By configuring in this way,
The power transmission device 20 of the hydraulic excavator 1 can be made compact, and the power transmission device 20 can be easily mounted on the hydraulic excavator 1.

In the present embodiment, as shown in FIG. 6A, power is transmitted between the input shaft 41 and the input / output shaft 91 via the pulley 48, the belt 93, and the pulley 92. However, the present invention is not limited to this.
That is, as shown in FIG. 6B, it is possible to adopt a configuration in which power is transmitted through the gear 48a and the gear 92a.
Further, as shown in FIG. 7A, the gear 92b fixed to the input / output shaft 91 is engaged with the gear 42 to transmit power between the input shaft 41 and the input / output shaft 91. It is also possible.

Further, the first hydraulic pump 40 and the second hydraulic pump 50 according to the present embodiment are configured so that the axes of the input shaft 41 and the input shaft 51 are the same as shown in FIGS. 6 (a), 6 (b) and 7 (a). The so-called swash plate type axial piston pump in which the axes of the cylinder block 43 and the cylinder block 53 are on the same straight line is described, but the present invention is not limited to this.
That is, as shown in FIG. 7B, the first hydraulic pump 40 and the second hydraulic pump 50 are configured such that the axis lines of the cylinder block 43 and the cylinder block 53 are respectively predetermined with respect to the axis lines of the input shaft 41 and the input shaft 51. A so-called oblique axis type axial piston pump inclined at an angle may be used.

Moreover, although the power transmission device 20 according to the present embodiment includes two hydraulic pumps (the first hydraulic pump 40 and the second hydraulic pump 50) as hydraulic pumps, the present invention is not limited to this. A configuration including three or more hydraulic pumps is also possible.

The present invention can be used for the technology of the arrangement configuration of each component in a power transmission device of a hydraulic excavator that can use an engine and a motor generator as a drive source of a hydraulic pump.

Claims

At least two hydraulic pumps for pumping hydraulic oil to the hydraulic actuator;
A motor generator that drives the at least two hydraulic pumps when supplied with electric power or generates electric power when driven by an engine;
A clutch for connecting and disconnecting power transmitted from the engine to the at least two hydraulic pumps and the motor generator;
Comprising
A power transmission device for a hydraulic excavator that drives the at least two hydraulic pumps by the engine and / or the motor generator,
Arranging the at least two hydraulic pumps and the motor generator in parallel;
The at least two hydraulic pumps, the motor generator, and the clutch are configured integrally.
Power transmission device for hydraulic excavators.
The at least two hydraulic pumps, the motor generator, and the clutch, and a flywheel cover that covers the flywheel of the engine are integrally configured.
The power transmission device for a hydraulic excavator according to claim 1.