JP5461795B2 - Hybrid construction machine drive system - Google Patents

Description

  The present invention relates to a hybrid construction machine drive system having a first drive mode in which a hydraulic pump and a generator motor are driven by an engine and a second drive mode in which the hydraulic pump is driven by the engine and the generator motor, and in particular, a generator motor. It is related with the drive system of the hybrid type construction machine which can suppress generation | occurrence | production of the power loss at the time of power transmission, without restrict | limiting excessively the electric power generation by A.

  2. Description of the Related Art Conventionally, there is known a drive device for a parallel hybrid construction machine that directly connects all rotation shafts of an engine, a generator motor, and a hydraulic pump without interposing a gear box between the engine, the hydraulic pump, and the generator motor. (For example, refer to Patent Document 1).

A drive device of a general parallel hybrid construction machine transmits the rotational force of the engine to each of the hydraulic pump and the generator motor via a gear box, and the drive device described in Patent Document 1 By connecting the generator motor and the hydraulic pump directly in that order, the power loss that occurred in the gearbox was eliminated during power transmission, and a cooling device was installed to cool the heat generated during the power loss. Is unnecessary.
JP 2007-210803 A

  However, since the drive device described in Patent Document 1 rotates the rotation shafts of the engine, the hydraulic pump, and the generator motor at a constant speed, the rotation speed of the rotation shaft of the generator motor is set to the same rotation speed as the rotation shaft of the engine. This will limit the amount of power generated by the generator motor to a low level.

  In view of the above, the present invention provides a drive system for a hybrid construction machine that can drive a hydraulic pump while suppressing generation of power loss during power transmission without excessively limiting power generation by a generator motor. For the purpose.

  In order to solve the above-described problems, a drive system for a hybrid construction machine according to a first aspect of the present invention includes a first drive mode in which a hydraulic pump and a generator motor are driven by an engine, and a hydraulic pump that is driven by the engine and the generator motor. A drive system for a hybrid construction machine having a second drive mode, wherein the engine rotation shaft and the rotation shaft of either the hydraulic pump or the generator motor are directly connected, and the engine rotation shaft, or The one rotation shaft directly connected to the rotation shaft of the engine is connected to the other rotation shaft through a transmission mechanism.

  The second invention is a drive system for a hybrid construction machine according to the first invention, wherein the rotation shaft of the engine and the other rotation shaft connected via the speed change mechanism are arranged in an offset manner. It is characterized by doing.

  A third invention is a drive system for a hybrid construction machine according to the first invention, wherein the speed change mechanism is a planetary gear mechanism, and is connected to the rotation shaft of the engine via the speed change mechanism. The other rotating shaft is coaxially disposed.

  Further, a fourth invention is a drive system for a hybrid construction machine according to any one of the first to third inventions, wherein the rotary shaft of the engine and the rotary shaft of the hydraulic pump are directly connected, and the hydraulic pressure The rotary shaft of the pump and the rotary shaft of the generator motor are connected via a speed increasing mechanism.

  By the above means, the present invention provides a drive system for a hybrid construction machine that can drive a hydraulic pump while suppressing generation of power loss during power transmission without excessively limiting power generation by a generator motor. Can do.

  Embodiments of the present invention will be described below.

  FIG. 1 is a diagram showing a configuration example of a hybrid construction machine on which a drive system according to the present invention is mounted. The hybrid construction machine 1 is placed on a crawler type lower traveling body 2 via a turning mechanism. A hydraulic excavator in which the upper swing body 3 is mounted so as to be swingable around the X axis.

  The upper swing body 3 includes a boom 4, an arm 5 and a bucket 6, and a boom cylinder 7, an arm cylinder 8 and a bucket cylinder 9 as hydraulic cylinders for driving the boom 4, the arm 5 and the bucket 6, respectively. Is provided.

  FIG. 2 is a schematic diagram of a drive system 100 according to the present invention. The drive system 100 includes an engine 21, a transmission mechanism 22, a generator motor 23, an inverter 24, a battery 25, a main controller 26, a hydraulic pump 27, and a turning electric motor. 28, a control valve 29, a boom operation lever 30, a turning operation lever 31, and a pressure sensor 32.

  The engine 21 is an internal combustion engine capable of driving the hydraulic pump 27 while rotating at a predetermined engine speed and simultaneously driving the generator motor 23 via the speed change mechanism 22, such as a gasoline engine or a diesel engine. The rotation number is output to the main controller 26.

  The speed change mechanism 22 is a device for transmitting the rotational force of the engine 21 to the generator motor 23 at a predetermined speed ratio. For example, the rotation shaft of the hydraulic pump 27 directly connected to the rotation shaft SFT1 of the engine 21 rotating at 2000 rpm. While using SFT2 as an input shaft and rotating shaft SFT3 of generator motor 23 as an output shaft, the output shaft is accelerated to 4000 to 8000 rpm.

  Further, FIG. 2 shows the rotating shaft SFT1 of the engine 21 rotating at a constant speed and the rotating shaft SFT2 of the hydraulic pump 27 by a black thick line, and the rotating shaft SFT3 of the generator motor 23 rotating at a higher speed than these two rotating shafts. Is indicated by a thick gray line.

  The generator motor 23 is a device for converting mechanical energy into electric energy by electromagnetic action to produce electric power, while converting electric energy into mechanical energy to produce rotational force. Various shapes such as a vertically long shape and a flat shape can be selected in accordance with the shape of the other component parts.

  This is to reduce the size and space of the drive system 100 so as not to create a useless space in the drive system 100 when combined with the hydraulic pump 27 and other related components.

  The generator motor 23 supplies, for example, electric energy generated by being driven by the engine 21 to an electric power supply destination (including the turning electric motor 28) via the inverter 24, or the generated electric energy is supplied. It functions as a generator that charges the battery 25 via the inverter 24, while giving assist torque to the hydraulic pump 27 driven by the engine 21 while using the electrical energy stored in the battery 25 via the inverter 24. Functions as an electric motor.

  The inverter 24 is a device for converting alternating current power and direct current power. For example, the inverter 24 converts the alternating current power produced by the generator motor 23 into direct current power and charges the battery 25 or the turning electric motor 28. Or the DC power of the battery 25 is converted into AC power based on a control signal output from the main controller 26 and supplied to the generator motor 23 or the turning motor 28. The inverter 24 may be integrated with the main controller 26.

  The battery 25 is a device that can recover not only the discharge but also the original state by discharging, for example, a lead storage battery, a lithium ion battery, a nickel metal hydride battery, an electric double layer capacitor, etc. The remaining capacity is output to the main controller 26.

  The main controller 26 is a device for controlling the drive system 100, and includes, for example, a computer having a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), etc., and motor control means 260, causing the CPU to execute arithmetic processing corresponding to each means while storing programs corresponding to each of the assist torque control means 261 and the power generation control means 262 in the ROM.

  The motor control means 260 of the main controller 26 acquires, for example, information on the electrical energy required by the turning motor 28 based on the signal output of the turning operation lever 31, and the generator motor 23 operates based on the signal output of the pressure sensor 32. Information on electrical energy that can be supplied (power generation) is acquired, and information on electrical energy that can be supplied (discharged) by the battery 25 is acquired based on the signal output of the battery 25, so that each of the generator motor 23 and the battery 25 The electric energy to be supplied to the turning electric motor 28 is calculated.

  Then, the motor control means 260 of the main controller 26 outputs a control signal to the inverter 24 based on the calculation result, and controls the generator motor 23 with a control current (for example, a field current supplied to the rotor). The electric energy of the generator motor 23 and the battery 25 can be supplied to the turning electric motor 28.

  The electric energy that can be generated by the generator motor 23 is calculated based on the residual torque obtained by subtracting the absorption torque of the hydraulic pump 27 from the output torque of the engine 21, and the output torque of the engine 21 is the number of revolutions output by the engine 21. The absorption torque of the hydraulic pump 27 is calculated based on the discharge pressure of the hydraulic pump 27 detected by the pressure sensor 32 (the absorption torque of the hydraulic pump 27 increases as the discharge pressure increases).

  The assist torque control means 261 of the main controller 26 calculates the absorption torque of the hydraulic pump 27 based on the signal output of the pressure sensor 32, and the residual that is the difference between the output torque of the engine 21 and the absorption torque of the hydraulic pump 27. When the torque becomes less than a predetermined value, a control signal is output to the inverter 24 to supply electric energy from the battery 25 to the generator motor 23 so that the generator motor 23 functions as an electric motor. Assist torque for rotating the SFT 2 is supplied.

  Thereby, the rotating shaft SFT2 of the hydraulic pump 27 is rotated by the output torque of the engine 21 and the assist torque of the generator motor 23.

  The power generation control means 262 of the main controller 26 controls the power generation amount of the generator motor 23 within the range of the remaining torque while changing the magnitude of the control current (field current) output to the generator motor 23.

  This is to prevent the absorption torque of the hydraulic pump 27 from exceeding the output torque of the engine 21 and stopping the engine.

  The hydraulic pump 27 is a pump for discharging pressure oil, and is the first drive mode driven only by the output torque of the engine 21 or the sum of the output torque of the engine 21 and the assist torque generated by the generator motor 23. The second drive mode is driven by torque, and pressure oil is supplied to a hydraulic actuator such as the boom cylinder 7, the arm cylinder 8 or the bucket cylinder 9 while changing the discharge amount Q as necessary.

  When the hydraulic pump 27 is driven in the first drive mode, the main controller 26 supplies a control current to the generator motor 23 to execute power generation using the remaining torque, but there is no need for power generation. (When the remaining battery capacity is sufficient), the supply of the control current to the generator motor 23 is stopped and the generator motor 23 is rotated without load.

  The turning electric motor 28 is an electric motor for turning the upper-part turning body 3. For example, the turning electric motor 28 is supplied from the electric energy supplied from the generator motor 23 functioning as a generator under the control of the main controller 26 or supplied from the battery 25. The upper turning body 3 is turned according to the operation amount of the turning operation lever 31 while using the electric energy.

  In FIG. 2, the turning electric motor 28 is merely a representative example of the electric motor in the hydraulic excavator 1, and other electric motors can be used instead of the turning electric motor 28 or in addition to the turning electric motor 28.

  The control valve 29 is a valve for supplying the pressure oil discharged from the hydraulic pump 27 to the hydraulic actuator and discharging the pressure oil in the hydraulic actuator to the pressure oil tank T. For example, the control valve 29 is supplied from the boom operation lever 30. The control pressure is received by the pilot port, and the boom cylinder 7 is expanded and contracted by switching the pressure oil conduit between the hydraulic pump 27 and the boom cylinder 7 while moving the spool in accordance with the control pressure.

  In FIG. 2, the boom cylinder 7 is merely a representative example of the hydraulic actuator in the excavator 1, and instead of the boom cylinder 7 or in addition to the boom cylinder 7, the arm cylinder 8, the bucket cylinder 9, or the traveling motor. Other hydraulic actuators can be utilized.

  The boom operation lever 30 is an operation device for operating the boom 4, and for example, pressure oil discharged from an auxiliary pump (not shown) according to the tilting operation of the lever is set to any one of the control pressure lines L <b> 1 and L <b> 2. The resulting control pressure is transmitted to the pilot port of the control valve 29 as a lever operation amount.

  The boom operation lever 30 employs a configuration using pressure oil in FIG. 2. However, the boom operation lever 30 electrically detects the tilting operation of the lever and electrically transmits the lever operation amount to the control valve 29. May be adopted.

  The turning operation lever 31 is an operating device for operating the turning of the upper turning body 3, and outputs, for example, a value detected by a potentiometer linked to the tilting operation of the lever to the main controller 26 as a lever operation amount.

  Next, various arrangements of the three components (the engine 21, the generator motor 23, and the hydraulic pump 27) in the drive system 100 will be described with reference to FIGS.

  FIG. 3 shows a state in which the rotation shaft SFT2 of the hydraulic pump 27 directly connected to the rotation shaft SFT1 of the engine 21 and the rotation shaft SFT3 of the generator motor 23 are arranged in parallel with a distance D therebetween. The transmission mechanism 22 is mounted on a rotary shaft SFT2 that extends on the opposite side of the engine 21 as viewed from the hydraulic pump 27 (the right side of the hydraulic pump 27 in the figure), and includes a spur gear (spur gear) and a helical gear (helical gear). Gear), an internal gear (internal gear) and the like. For the sake of clarity, the speed increase by one stage is shown, but the number of speed increase stages is not limited. The same applies to the following drawings.

  Due to this parallel arrangement, the drive system 100 can reduce its overall length (length in the left-right direction in the figure).

  FIG. 4 shows a state in which the rotation shaft SFT2 of the hydraulic pump 27 directly connected to the rotation shaft SFT1 of the engine 21 and the rotation shaft SFT3 of the generator motor 23 are inclined so as to intersect at an axis angle θ. The transmission mechanism 22 is mounted on a rotation shaft SFT2 that extends on the opposite side of the engine 21 when viewed from the hydraulic pump 27 (the right side of the hydraulic pump 27 in the drawing), and is configured by a bevel gear (bevel gear) or the like.

  With this inclined arrangement, the drive system 100 attempts to place the rotation axis SFT2 of the hydraulic pump 27 directly connected to the rotation axis SFT1 of the engine 21 and the rotation axis SFT3 of the generator motor 23 in parallel (see FIG. 3). ) Even when the hydraulic pump 27 and the generator motor 23 interfere with each other and cannot be arranged in parallel, the hydraulic pump 27 and the generator motor 23 can be arranged close to each other without causing interference.

  FIG. 5 shows that the rotation shaft SFT2 of the hydraulic pump 27 that is directly connected to the rotation shaft SFT1 of the engine 21 and the rotation shaft SFT3 of the generator motor 23 are arranged so as to be shifted without being arranged in parallel and inclined (hereinafter referred to as “misalignment arrangement”). ")"). In FIG. 5, the rotating shaft SFT3 of the generator motor 23 is perpendicular to the paper surface, and the speed change mechanism 22 rotates to the side opposite to the engine 21 as viewed from the hydraulic pump 27 (the right side of the hydraulic pump 27 in the figure). It is mounted on the shaft SFT2 and is composed of a spiral gear (screw gear), a worm gear, or the like.

  FIG. 6 shows a state where the rotation shaft SFT2 of the hydraulic pump 27 directly connected to the rotation shaft SFT1 of the engine 21 and the rotation shaft SFT3 of the generator motor 23 are arranged on the same axis. The transmission mechanism 22 is mounted on a rotation shaft SFT2 that extends to the opposite side of the engine 21 when viewed from the hydraulic pump 27 (the right side of the hydraulic pump 27 in the figure), and includes a planetary gear mechanism or the like.

  In FIG. 7, the rotation shaft SFT2 of the hydraulic pump 27 directly connected to the rotation shaft SFT1 of the engine 21 and the rotation shaft SFT3 of the generator motor 23 are arranged in parallel, and the speed change attached between the engine 21 and the hydraulic pump 27. The state which connected these rotating shafts via the mechanism 22 is shown. The speed change mechanism 22 is mounted on a rotary shaft SFT1 or SFT2 on the same side as the engine 21 when viewed from the hydraulic pump 27 (left side of the hydraulic pump 27 in the figure), and is configured by a spur gear or the like.

  With the above configuration, the drive system 100 suppresses the generation of power loss during power transmission by directly connecting the rotation shaft SFT1 of the engine 21 and the rotation shaft SFT2 of the hydraulic pump 27, and the rotation of the hydraulic pump 27 The hydraulic pump 27 can be driven without excessively restricting power generation by the generator motor by increasing the number of rotations of the shaft SFT2 and then transmitting the force to the rotation shaft SFT3 of the generator motor 23.

  Further, since the drive system 100 can freely set the size (volume) of the assembly in which the hydraulic pump 27 and the generator motor 23 are combined using the various speed change mechanisms 22 as described above, the drive system 100 can be reduced in size and space. In addition, it is possible to flexibly cope with combinations with other related components.

  The “offset arrangement” in the claims includes “parallel arrangement”, “inclined arrangement”, and “misalignment arrangement” in the above-described embodiments.

  Although the embodiment of the present invention has been described in detail above, the present invention is not limited to the specific embodiment, and various modifications and changes are within the scope of the gist of the present invention described in the claims. It can be changed.

  For example, in the above-described embodiment, the drive system 100 directly connects the rotary shaft SFT1 of the engine 21 and the rotary shaft SFT2 of the hydraulic pump 27, and increases the rotary shaft SFT2 of the hydraulic pump 27 and the rotary shaft SFT3 of the generator motor 23. The rotary shaft SFT1 of the engine 21 and the rotary shaft SFT3 of the generator motor 23 are directly connected, and the rotary shaft SFT3 of the generator motor 23 and the rotary shaft SFT2 of the hydraulic pump 27 are connected via a speed reduction mechanism. You may make it connect.

  Thus, the drive system 100 directly connects the rotating shaft SFT1 of the high-rotation type engine 21 and the rotating shaft SFT3 of the generator motor 23 to rotate the generator motor 23 at high speed while suppressing the occurrence of power loss during power transmission. On the other hand, since the hydraulic pump 27 is driven after the rotational speed is reduced by the speed reduction mechanism 22 and a large torque is generated, generation of power loss at the time of power transmission is generated without excessively limiting power generation by the generator motor. The hydraulic pump 27 can be driven while suppressing this.

  In the above-described embodiment, the drive system 100 arranges both the generator motor 23 and the hydraulic pump 27 on one side of the engine 21, but the generator motor 23 is arranged on one side of the engine 21, and the engine 21. Alternatively, the hydraulic pump 27 may be disposed on the other side.

It is a figure which shows the structural example of the hybrid type construction machine by which the drive system which concerns on this invention is mounted. It is the schematic of the drive system which concerns on this invention. It is FIG. (1) which shows the example of arrangement | positioning of the engine in a drive system, a hydraulic pump, and a generator motor. FIG. 6 is a diagram (part 2) illustrating an arrangement example of the engine, the hydraulic pump, and the generator motor in the drive system. FIG. 9 is a third diagram illustrating an arrangement example of the engine, the hydraulic pump, and the generator motor in the drive system. FIG. 8 is a diagram (No. 4) illustrating an arrangement example of the engine, the hydraulic pump, and the generator motor in the drive system. FIG. 10 is a fifth diagram illustrating an arrangement example of the engine, the hydraulic pump, and the generator motor in the drive system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Hydraulic excavator 2 ... Lower traveling body 3 ... Upper turning body 4 ... Boom 5 ... Arm 6 ... Bucket 7 ... Boom cylinder 8 ... Arm cylinder 9 ... Bucket cylinder 21 ... Engine 22 ... Speed change mechanism 23 ... Generator motor 24 ... Inverter 25 ... Battery 26 ... Main controller 27 ... Hydraulic pump 28 ... Rotating motor 29 ... Control valve 30 ... Boom operation lever 31 ... Turning operation lever 32 ... Pressure sensor 100 ... Drive system L1, L2 ... Control pressure lines SFT1 to SFT3 ... Rotation shaft T ..Pressure oil tank

Claims (2)

A hybrid construction machine drive system having a first drive mode for driving a hydraulic pump and a generator motor for supplying pressure oil to a hydraulic actuator by an engine and a second drive mode for driving a hydraulic pump by the engine and the generator motor. And
Directly connecting the rotating shaft of the engine and the hydraulic pump ;
Connecting the rotating shaft of the engine and the rotating shaft of the motor generator via a transmission mechanism ;
The rotational axis of the engine and the rotational axis of the motor generator are offset .
High comb than the rotational speed of the rotating shaft of the hydraulic pump the rotation speed of the rotating shaft of the generator motor by the speed change mechanism,
The power generation amount of the generator motor is controlled by the magnitude of the field current of the rotor,
The drive system for a hybrid type construction machine , wherein a discharge amount of the hydraulic pump is changed so that a supply amount of pressure oil to the hydraulic actuator is changed . Controlling the generator motor based on a signal output of a pressure sensor for detecting a discharge pressure of the hydraulic pump;
The drive system for a hybrid type construction machine according to claim 1 .