JP2010065510A - Driving device for working machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a driving device for a working machine excelling in generating efficiency (energy regeneration efficiency) in stopping the swing of a super structure. <P>SOLUTION: The driving device for the working machine for driving the super structure 14 swingably mounted to a base body 12 comprises a swinging hydraulic motor 52 driving the super structure 14; a swinging electric generator 64 capable of driving the super structure 14 together with the swinging hydraulic motor 52 and carrying out regenerative power generation when the speed of the super structure 14 is reduced; and a short circuit selector valve 56 capable of short-circuiting an inlet and an outlet of an operating fluid of the swinging hydraulic motor 52. In the regenerative power generation of the super structure 14, the operating fluid inlet and outlet M3, M4 of the swinging hydraulic motor 52 are short-circuited. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a drive device for a work machine such as a construction machine.

  Construction machines (work machines) including a lower traveling body (base body), an upper swing body, and an arm mechanism (front attachment) are widely used.

  The upper turning body is connected to the lower traveling body so as to be able to turn, and has a large inertial kinetic energy when turning. However, conventionally, this inertial kinetic energy has been discarded as loss when hydraulic fluid flows in the hydraulic circuit of the hydraulic drive.

  On the other hand, in Patent Document 1, the upper turning body is driven by a turning hydraulic motor and a turning motor generator, and the turning electric motor is provided with driving assistance and power generation (energy regeneration). ) Is disclosed.

JP 2004-124381 A

  However, even in the technique described in Patent Document 1, there is a large loss when stopping the turning of the upper swing body, and the power generation efficiency (energy regeneration efficiency) utilizing the inertial kinetic energy of the swing of the upper swing body is not sufficient. There was a problem.

  This invention is made in view of this problem, Comprising: It aims at providing the drive device of the working machine with favorable electric power generation efficiency (energy regeneration efficiency) at the time of stopping turning of an upper turning body. .

  The present invention relates to a drive device for a work machine that drives an upper swing body that is pivotably attached to a base body, and a swing hydraulic motor that drives the upper swing body, and the upper swing body is driven together with the swing hydraulic motor. A revolving power generator capable of performing regenerative power generation when the upper revolving body is decelerated, and a short-circuit switching valve capable of short-circuiting an inlet and an outlet of hydraulic oil of the revolving hydraulic motor, the upper revolving body This problem is solved by short-circuiting the inlet and outlet of the hydraulic oil of the turning hydraulic motor during regenerative power generation.

  According to this configuration, the inlet and outlet of the hydraulic oil of the turning hydraulic motor can be short-circuited by the short-circuit switching valve during regenerative power generation of the upper-part turning body. By short-circuiting with the short-circuit switching valve, the loss due to the so-called rotating load of the swing hydraulic motor in the hydraulic circuit at the time of regenerative power generation of the upper swing body is almost eliminated, and most of the inertial force of the upper swing body is transferred to the swing motor generator. Therefore, the inertial kinetic energy of the upper swing body can be efficiently converted (regenerated) into electric energy.

  When the hydraulic circuit that drives the turning hydraulic motor is provided with a brake valve mechanism that functions as a hydraulic brake for the turning hydraulic motor, the hydraulic brake by the brake valve mechanism is caused by the short-circuit switching valve. Can also be released, and the inertial kinetic energy of the upper-part turning body can be efficiently converted (regenerated) into electric energy.

  When the brake valve mechanism is provided in the hydraulic circuit in this way, the hydraulic brake by the brake valve mechanism may be used only immediately after the upper swing body stops turning. Thereby, the position of the upper turning body immediately after the stop is difficult to move, and the turning motor generator including the mechanical brake mechanism can be downsized.

  According to the present invention, the power generation efficiency (energy regeneration efficiency) when stopping the turning of the upper turning body is good.

  Hereinafter, an example of a preferred embodiment of a drive device for a work machine according to the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a block configuration diagram illustrating a drive device for a work machine according to an example of an embodiment of the present invention, FIG. 2 is an enlarged view of a main part thereof, and FIG. 3 is a hydraulic excavator (work machine) to which the present invention is applied. ) Is a perspective view showing the overall configuration of 10.

  As shown in FIG. 3, the excavator 10 includes a lower traveling body (base body) 12, an upper swing body 14, and an arm mechanism 16.

  The upper turning body 14 is connected to the lower traveling body 12 so as to be able to turn, and can be turned by being supplied with driving force from a turning hydraulic motor 52 and a turning motor generator 64 which will be described later. . The upper swing body 14 includes a cab (operator's cab) 30 on the front side, and an arm mechanism 16 is attached to the side of the cab 30.

  The arm mechanism 16 includes three links including a boom 32, an arm 34, and a bucket 36, and a boom cylinder 38, an arm cylinder 40, and a bucket cylinder 42 that drive the links.

  Next, the configuration of the drive device for the work machine according to the present embodiment will be described in more detail with reference to FIGS. 1 and 2.

  As shown in FIG. 2, the output shaft 1a of the engine 1 includes a motor generator 2 that functions not only as a motor but also as a generator, and a main pump that supplies hydraulic oil to a hydraulic actuator (a variable displacement hydraulic pressure). Pumps 3A and 3B and a pilot pump 3C for supplying hydraulic oil to the pilot circuit are attached in parallel.

  The motor generator 2 is connected with a converter 4 having both a converter function for converting alternating current into direct current and an inverter function for converting direct current into alternating current, and a battery 5 and a controller 6 are connected to the converter 4. Has been.

  The battery 5 has a function of transferring electric energy to and from the motor generator 2 via the conversion device 4, and the regenerative electric energy collected during deceleration of the motor generator 2 is transferred via the conversion device 4. Can be stored. On the other hand, when the motor generator 2 is operated, the battery 5 can supply electric energy to the motor generator 2 via the conversion device 4 to operate the motor generator 2 as an electric motor.

  The control valve group 50 is automatically operated in accordance with the movement of an operation lever (not shown) operated by an operator, and hydraulic actuators other than the turning hydraulic motor 52 (boom cylinder 38, arm cylinder 40, bucket cylinder 42, right traveling). The pressure, flow rate, and direction of the hydraulic fluid flowing in the hydraulic circuit for the hydraulic motor 22 and the left traveling hydraulic motor 24) are controlled.

  As shown in FIG. 2, the control valve group 50 includes a right traveling control valve 100, a left traveling control valve 102, a boom cylinder control valve 104, an arm cylinder control valve 106, a bucket cylinder control valve 108, and a preliminary control. Valves 110 and 112 and switching valves 114, 116 and 118 are provided. One of the preliminary control valves 110 and 112 is normally used as a control valve for turning the upper swing body 14, but in the present embodiment, a rotary remote control lever device 62, which will be described later, is provided. There are two, and two preliminary control valves can be used for other applications.

  A turning control valve 54 is provided between the turning hydraulic motor 52 and the main pump 3A, and a short-circuit switching valve 56 is provided between the turning control valve 54 and the turning hydraulic motor 52. A hydraulic brake valve mechanism 60 is provided between the switching valve 56 and the turning hydraulic motor 52. The hydraulic brake valve mechanism 60 includes relief valves 60A and 60B and check valves 60C and 60D.

  The turning control valve 54 is a three-position / four-port switching valve, and has three switching positions A, B, and C, and controls the flow direction and flow rate of hydraulic fluid from the main pump 3A toward the turning hydraulic motor 52. To do. Pilot ports 54a and 54b are provided at both ends of the spool of the turning control valve 54, respectively. Further, both ends of the spool of the turning control valve 54 are urged by springs 54c and 54d.

  The position of the spool of the turning control valve 54 is switched by operating the turning remote control lever device 62. The turning remote control lever device 62 includes a lever 62a, remote control valves 62b and 62c, and a pilot pump 3c.

  Note that the three positions A, B, and C of the spool of the turning control valve 54 schematically show typical states, and do not switch to each position in a step shape, but flow of hydraulic oil. Can be switched smoothly including the intermediate position B toward the A side or the C side, with the neutral position B in a completely blocked state as the center. Therefore, when the operator operates the turning remote control lever device 62 to control the switching state from the neutral position B to the operating state A, C, the hydraulic oil supply flow rate can be variably controlled.

  The short-circuit switching valve 56 is a two-position / four-port switching valve, has two switching positions D and E, and has four ports P1, P2, M1, and M2. The short-circuit switching valve 56 has a role of short-circuiting the hydraulic oil ports M3 and M4 of the turning hydraulic motor 52 (short-circuiting the two ports M1 and M2 on the turning hydraulic motor 52 side). A solenoid portion 56 a is provided at one end of the spool of the short-circuit switching valve 56. The other end of the spool of the short-circuit switching valve 56 is biased by a spring 56b and is always biased to the switching position D side.

  When an electrical signal indicating that regenerative power generation is in progress is input to the electrical signal line 6b, the solenoid unit 56a pushes the spool of the short-circuit switching valve 56 so as to compress and retract the spring 56b, moves the spool to the switching position E, and turns The hydraulic oil inlets and outlets M3 and M4 of the hydraulic motor 52 are short-circuited (the two ports M1 and M2 on the turning hydraulic motor 52 side are short-circuited). On the other hand, when the controller 6 determines that the regenerative power generation is finished (in this embodiment, the turn is finished: the rotation speed of the turning motor generator 64 is zero), the supply of electricity to the electric signal line 6b is cut off, and the short circuit switching valve 56 is turned off. The spool is pushed by the urging force of the spring 56b to move to the switching position D, and the hydraulic oil outlets M3 and M4 of the turning hydraulic motor 52 are short-circuited (the two ports M1 and M2 on the turning hydraulic motor 52 side are short-circuited). Is released.

  The hydraulic brake valve mechanism 60 includes relief valves 60A and 60B and check valves 60C and 60D. The relief valves 60A and 60B are opened when the pressure of the hydraulic circuit for the turning hydraulic motor 52 becomes equal to or higher than the set pressure, and the hydraulic oil is relieved. Check valves 60C and 60D prevent cavitation.

  Since the hydraulic brake valve mechanism 60 is arranged in parallel with the turning hydraulic motor, the spool of the short-circuit switching valve 56 moves to the switching position E, and the hydraulic oil outlets M3 and M4 of the turning hydraulic motor 52 are short-circuited ( When the two ports M1 and M2 on the turning hydraulic motor 52 side are short-circuited), the hydraulic brake valve mechanism 60 is also short-circuited and the hydraulic brake is released.

  As a result, after all, the hydraulic brake by the hydraulic brake valve mechanism 60 is used only immediately after the turning is stopped.

  The driving force is supplied to the upper swing body 14 by the turning hydraulic motor 52 and the turning motor generator 64, and the turning hydraulic motor 52 is connected to the drive shaft 64 a of the turning motor generator 64. The turning motor generator 64 assists the drive of the turning hydraulic motor 52 and performs regenerative power generation when the upper turning body 14 is decelerated. Therefore, in the present embodiment, the upper swing body 14 is driven by the total output of the swing hydraulic motor 52 and the swing motor generator 64. Further, a turning speed reducer 70 is attached to the turning motor generator 64, and the turning speed reducer 70 reduces the rotation of the drive shaft 64 a of the turning motor generator 64 and transmits it to the upper turning body 14.

  The turning motor generator 64 is connected to a converter 7 having both a converter function for converting alternating current to direct current and an inverter function for converting direct current to alternating current. The converter 7 is connected to the battery 5 and the controller 6. Is connected.

  The battery 5 has a function of transferring electrical energy to and from the turning motor generator 64 via the conversion device 7, and regenerative electricity generated by the turning motor generator 64 when the upper turning body 14 is decelerated. Energy can be stored via the converter 7. On the other hand, when the turning motor generator 64 operates as an electric motor, the battery 5 supplies electric energy to the turning motor generator 64 via the converter 7.

  An angle detector (resolver) 72 and a mechanical brake 74 are attached to the drive shaft 64 a of the turning motor generator 64. The rotation speed information of the drive shaft 64a is obtained from the angle detector (resolver) 72, and the controller 6 determines whether or not regenerative power generation is performed. For example, when deceleration of the upper swing body 14 is detected, it can be determined that regenerative power generation is in progress, and therefore an electric signal for switching the short-circuit switching valve 56 to the switching position E is sent to the solenoid unit 56a.

  The mechanical brake 74 finally stops the turning of the upper turning body 14.

  Next, the operation of the work machine configured as described above will be described.

  When the engine 1 rotates, the motor generator 2 and the main pumps 3A and 3B are driven in common. The drive shaft 2a of the motor generator 2 rotates in a state that is greatly increased with respect to the rotation speed of the output shaft 1a of the engine 1 by a transmission (not shown), and performs predetermined power generation. The AC power generated by the motor generator 2 is converted into DC power by the conversion device 4 and then stored in the battery 5. On the other hand, the main pumps 3A and 3B are amplified and driven at a rotational speed slightly higher than the rotational speed of the output shaft 1a of the engine 1 by a transmission (not shown) to supply hydraulic oil.

  When supplying a hydraulic oil from the main pumps 3A and 3B to drive a predetermined hydraulic actuator, when a high load is applied to the main pumps 3A and 3B, electric power is supplied from the battery 5 to the motor generator 2 via the converter 4. The motor generator 2 is supplied as a motor. As a result, the motor generator 2 can perform torque assist of the engine 1 with respect to driving of the main pumps 3A, 3B, and can sufficiently drive the main pumps 3A, 3B even if the engine 1 is small. In addition, it is not necessary to always operate the engine 1 preliminarily at a high rotational speed so as to always respond to the maximum load of the main pumps 3A and 3B, and the maximum rotational speed of the engine 1 can be set low. Low energy work is possible at the same time as energy saving.

  Here, from the main pumps 3A, 3B to hydraulic actuators other than the turning hydraulic motor 52 (boom cylinder 38, arm cylinder 40, bucket cylinder 42, travel (right) hydraulic motor 22, travel (left) hydraulic motor 24). The hydraulic oil is supplied through the control valve group 50, but the hydraulic oil is supplied to the turning hydraulic motor 52 through the turning control valve 54 and the short-circuit switching valve 56.

  The spool of the turning control valve 54 is moved by the operator operating the turning remote control lever device 62, and controls the direction and flow rate of hydraulic oil supplied to the turning hydraulic motor 52.

  When the lever 62a is tilted to the R side in FIG. 1, the remote control valve 62b switches to a position where the pilot pump 3C and the pilot port 54a communicate with each other, and the spool of the turning control valve 54 moves to the left in FIG. It becomes the switching position A. Since the short-circuit switching valve 56 is normally in the switching position D, the hydraulic oil (pressure oil) from the main pump 3A flows in the order of the port P1, the port M1, and the inlet / outlet M3 and flows into the turning hydraulic motor 52. . The hydraulic oil (return oil) from the turning hydraulic motor 52 flows in the order of the inlet / outlet M4, the port M2, and the port P2, and is discharged to the tank. Therefore, the turning hydraulic motor 52 rotates in one direction. When the lever 62a is tilted to the L side in FIG. 1, the remote control valve 62c is switched to a position where the pilot pump 3C and the pilot port 54b communicate with each other, and the spool of the turning control valve 54 moves to the right in FIG. It becomes the switching position C. As a result, the hydraulic oil (pressure oil) from the main pump 3A flows in the order of the port P2, the port M2, and the inlet / outlet M4 and flows into the turning hydraulic motor 52. The hydraulic oil (return oil) from the turning hydraulic motor 52 flows in the order of the inlet / outlet M3, the port M1, and the port P1, and is discharged to the tank. Therefore, the turning hydraulic motor 52 rotates in the reverse direction. When the lever 62a is returned to the neutral position in FIG. 1, no pilot pressure is applied to either of the pilot ports 54a and 54b, and the spool of the turning control valve 54 is in the neutral position by the urging force of the springs 54c and 54d. B, the supply of hydraulic oil to the turning hydraulic motor 52 is blocked by the ports P3 and P4, and the turning hydraulic motor 52 stops.

  The position of the spool of the short-circuit switching valve 56 is switched depending on whether or not electricity is supplied to the solenoid portion 56a of the short-circuit switching valve 56. In a state where electricity is not supplied to the solenoid portion 56a, the spool of the short-circuit switching valve 56 is located at the switching position D by the urging force of the spring 56b, and the port P1 and the port M1 communicate with each other, and the port P2 and the port M2 Are communicating. In this state, the hydraulic oil (pressure oil) supplied from the main pump 3A and the hydraulic oil (return oil) from the turning hydraulic motor 52 smoothly pass through the short-circuit switching valve 56. By setting the spool position of the control valve 54 to position A or C, the turning hydraulic motor 52 can be operated in either direction.

  In this embodiment, the controller 6 switches the short-circuit switching valve 56 based on the rotational speed information of the drive shaft 64 a of the turning motor generator 64 detected by the angle detector (resolver) 72. When the controller 6 detects the deceleration of the upper swing body 14, the controller 6 sends an electric signal to the solenoid unit 56a via the electric signal line 6b. In the short-circuit switching valve 56, the spool moves to the right in FIG. As a result, the hydraulic oil outlets M3 and M4 of the turning hydraulic motor 52 are short-circuited, and the power generation efficiency (energy regeneration efficiency) of the turning motor generator 64 is improved.

  Further, when the rotational speed of the drive shaft 64a of the turning motor generator 64 is less than or equal to a predetermined value or zero during regenerative power generation, the controller 6 determines that the regenerative power generation has ended, and until then the electric signal line 6b Cut off the electrical signal that was being sent. For this reason, the spool of the short-circuit switching valve 56 moves leftward in FIG. 1 and returns to the switching position D by the urging force of the spring 56b. As a result, the hydraulic circuit for the turning hydraulic motor 52 is released from the short circuit.

  When the hydraulic oil outlets M3 and M4 of the turning hydraulic motor 52 are short-circuited (two ports M1 and M2 on the turning hydraulic motor 52 side) are short-circuited by the short-circuit switching valve 56 during regenerative power generation, the turning hydraulic motor 52 is turned on. Thus, the turning hydraulic motor 52 does not become a substantial resistance to the turning of the upper turning body 14.

  Here, in the present embodiment, when the short-circuit switching valve 56 is switched to the switching position E, not only the hydraulic oil outlets M3 and M4 of the turning hydraulic motor 52 but also the hydraulic brake valve mechanism 60 are short-circuited simultaneously. Therefore, even if the hydraulic brake valve mechanism 60 is provided, the hydraulic brake by the hydraulic brake valve mechanism 60 does not function while the short-circuit switching valve 56 is in the switching position E.

  For this reason, most of the inertial force of the upper swing body 14 is applied to the turning motor generator 64. Therefore, when the turning motor generator 64 connected to the turning hydraulic motor 52 is caused to function as a generator. The inertial kinetic energy of the upper swing body 14 can be efficiently converted (regenerated) into electric energy. Since the upper swing body 14 is heavy and has a large inertial force, efficiently converting (regenerating) the inertial kinetic energy of the upper swing body 14 into electric energy has a great merit in terms of energy saving.

  Further, since the turning hydraulic motor 52 is connected to the drive shaft 64 a of the turning motor generator 64, the upper turning body 14 can be driven by both the turning hydraulic motor 52 and the turning motor generator 64. it can. For this reason, both the high output capability of the turning hydraulic motor 52 and the high controllability of the turning motor generator 64 can be utilized. As a result, it is possible to change the operating conditions flexibly according to the situation while maintaining a high output, and it is possible to reduce the size of the turning motor generator.

  On the other hand, the hydraulic fluid flows in the hydraulic circuit of the turning hydraulic motor 52 and the hydraulic brake valve mechanism 60 with almost no load due to the short circuit by the short circuit switching valve 56, but the short circuit occurs immediately after the upper swing body 14 stops turning. When released, the turning hydraulic motor 52 may receive a surge pressure from the flowing hydraulic fluid.

  However, by providing the hydraulic brake valve mechanism 60 in the hydraulic circuit for the turning hydraulic motor 52, the hydraulic brake by the hydraulic brake valve mechanism 60 works simultaneously with the release of the short circuit immediately after the turning of the upper turning body 14 is stopped. Therefore, the turning hydraulic motor 52 does not receive an excessive surge pressure. For this reason, even if the turning motor generator 64 including the mechanical brake 74 is reduced in size, the turning motor generator 64 is less affected by the hydraulic motor 52 after being stopped, and the turning motor generator 64 can be reduced in size.

  Further, when a pressing force at a low speed is required or when the position needs to be maintained, for example, when the arm mechanism 16 is held on an inclined ground, only the position holding function by the hydraulic brake valve mechanism 60 is sufficient. The holding torque by the turning motor generator 64 is not necessary.

  In addition, since the operation of the turning hydraulic motor 52 is controlled by the turning remote control lever device 62, the turning port (preliminary control valve 110 or 112) of the control valve group 50 can be used for other purposes. Spread and improve versatility.

  As mentioned above, although an example of suitable embodiment of the drive device of the working machine which concerns on this invention was demonstrated, the lower traveling body 12 does not need to have a traveling function, and an upper turning body is not provided in the base | substrate which does not have a traveling function. The present invention can also be applied to a work machine to which 14 is attached.

  Further, in this embodiment, the short-circuit switching valve 56 is configured to short-circuit the hydraulic brake valve mechanism 60. However, in the present invention, it is not always necessary to short-circuit the hydraulic brake valve mechanism 60.

  The present invention can be particularly effectively applied to a work machine having a large weight of a turning part, such as a construction work machine.

The block block diagram which shows the drive device of the working machine which concerns on an example of embodiment of this invention The principal part enlarged view of the drive device of the said working machine The perspective view which shows the whole structure of the hydraulic shovel (work machine) to which this invention was applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Engine 1a ... Output shaft 2 ... Motor generator 2a ... Drive shaft 3A, 3B ... Main pump 3C ... Pilot pump 4, 7 ... Conversion device 5 ... Battery 6 ... Controller 10 ... Hydraulic excavator 12 ... Undercarriage (base)
DESCRIPTION OF SYMBOLS 14 ... Upper turning body 50 ... Control valve group 52 ... Turning hydraulic motor 54 ... Turning control valve 56 ... Short-circuit switching valve 60 ... Hydraulic brake valve mechanism 60A, 60B ... Relief valve 60C, 60D ... Check valve 62 ... Swing remote control lever Device 64 ... turning motor generator 64a ... drive shaft 70 ... turning speed reducer 72 ... angle detector (resolver)
74 ... Mechanical brake P1, P2, P3, P4, M1, M2 ... Port M3, M4 ... Entrance / exit

Claims (3)

In a drive device for a work machine that drives an upper swing body that is pivotably attached to a base body,
A turning hydraulic motor for driving the upper turning body;
A turning motor generator capable of driving the upper turning body together with the turning hydraulic motor and performing regenerative power generation when the upper turning body is decelerated;
A short-circuit switching valve capable of short-circuiting the inlet and the outlet of the hydraulic oil of the turning hydraulic motor,
A drive device for a work machine, characterized in that an inlet and an outlet of hydraulic oil of the swing hydraulic motor are short-circuited during regenerative power generation of the upper swing body. In claim 1,
The hydraulic circuit for driving the turning hydraulic motor is provided with a brake valve mechanism that functions as a hydraulic brake for the turning hydraulic motor, and the hydraulic brake by the brake valve mechanism is controlled by the short-circuit switching valve. A work machine drive device characterized in that it can also be released. In claim 2,
The drive device for a working machine, wherein the hydraulic brake by the brake valve mechanism is used only immediately after turning of the upper swing body is stopped.

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