JP2016038074A - Control device for turning type work machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve both sufficient regeneration efficiency and high brake performance during turning and decelerating operation.SOLUTION: This invention relates to a control device for turning type work machine in which a rotation brake action is carried out through relief action of a relief valve during turning and decelerating operation and in turn oil energy is converted into rotating energy by a regeneration motor 21 to regenerate it. As the relief valve, variable relief valves 26, 27 changing characteristics of relief flow rate/relief pressure by an instruction signal sent from a controller 28 are applied and the characteristics of relief flow rate/relief pressure of the variable relief valves 26, 27 are changed to attain sufficient relief pressure to perform a turning brake action in regard to a relief flow rate Qr at that time during turning and deceleration.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a control device that performs an energy regenerative action during turning deceleration in a turning work machine such as a hydraulic excavator.

  The background art will be described using a hydraulic excavator as an example.

  As shown in FIG. 4, the excavator is mounted on a crawler-type lower traveling body 1 so that an upper swing body 2 is pivotable about an axis X perpendicular to the ground, and a work attachment 3 is attached to the upper swing body 2. Installed and configured.

  The work attachment 3 includes a boom 4 that can be raised and lowered, an arm 5 attached to the tip of the boom 4, a bucket 6 attached to the tip of the arm 5, and a boom, an arm, and a bucket cylinder that operates them ( (Hydraulic cylinder) 7,8,9.

  The lower traveling body 1 and the upper swing body 2 are driven and turned by a traveling hydraulic motor and a turning hydraulic motor (not shown), respectively.

  In this hydraulic excavator, energy due to the inertia of the upper-part turning body 2 works during turning deceleration.

  As a means for effectively using energy at the time of turning deceleration, as shown in Patent Document 1, a regenerative motor is connected to the engine, and the engine is assisted by rotating the regenerative motor with oil discharged from the hydraulic actuator. Techniques for doing this are well known.

  This known technique will be described with reference to FIG.

  In the figure, 10 is a hydraulic pump as a hydraulic source driven by the engine 11, and 12 is a swing motor that rotates by the pressure oil from the hydraulic pump 10 to drive the upper swing body 2 shown in FIG. Between the swing motor 12 and the hydraulic pump 10 and the tank T, there is provided a control valve 13 which is a hydraulic pilot type switching valve that is switched and operated by a pilot pressure from a remote control valve (not shown). 12 is controlled to supply / discharge pressure oil (rotation / stop of the turning motor 12, rotation direction, rotation speed).

  That is, when the remote control valve is not operated, the control valve 13 is set to the neutral position A shown in the figure. When the remote control valve is operated, the control valve 13 is moved from the neutral position A to the left side (for example, the left turn position) Same as the right turn position).

  At the neutral position A of the control valve 13, motor both-side conduits 14, 15 connecting the control valve 13 and the turning motor 12 (the left turning conduit on the left side and the right turning conduit on the right side) 14, 15 are connected to the pump 10. Since it is blocked, the turning motor 12 does not rotate.

  From this state, when the remote control valve is operated to the left turning side and the control valve 13 is switched to the left turning position B, the pressure oil is supplied from the pump 10 to the left turning pipeline 14 and the turning motor 12 rotates to the left. The upper swing body 2 turns left.

  On the other hand, when the remote control valve is operated to the right turning side and the control valve 13 is switched to the right turning position C, the pump oil is supplied to the right turning pipeline 15 and the turning motor 12 rotates to the right. The upper swing body 2 turns right.

  On the other hand, relief valves 16 and 17 as brake valves are provided opposite to each other between the two turning pipes 14 and 15, and in parallel therewith, a check valve for anti-cavitation (for preventing cavitation = oil suction) 18 and 19 are provided in an opposing arrangement.

  The outlet side of both relief valves 16 and 17 and the inlet side of both check valves 18 and 19 are connected by a communication passage 20, and this communication passage 20 is connected to the tank T.

  In the configuration so far, for example, when the control valve 13 returns from the left turning position B to the neutral position A, the turning motor 12 and the both turning pipelines 14 and 15 are disconnected from the pump 10 and the tank T, and the pressure applied to the turning motor 12 is increased. The supply of oil and the return of oil from the turning motor 12 to the tank T are stopped.

  Here, since the swing motor 12 tries to continue the left turn due to the inertia of the upper swing body 2, a pressure is generated in the right turn pipeline (meter-out side pipeline) 15 on the outflow side, and this reaches a certain value. Then, the relief valve 17 on the right side of the figure opens and the oil in the right turning pipe line 15 passes through the relief valve 17 -the communication path 20 -the check valve 18 on the left side of the figure and enters the left turning pipe line (meter-in side pipe line) 14. Enters and flows into the turning motor 12.

  At this time, if the left turning pipe line 14 tends to have a negative pressure, tank oil is sucked up from the communication path 20 to the left turning pipe line 14 via the check valve 18 to prevent cavitation.

  Thus, since the turning motor 12 receives the braking force due to the relief action while inertially rotating, it slowly stops. The same applies when stopping from a right turn.

  On the other hand, a variable capacity regenerative motor (hydraulic motor) 21 is connected to the engine 11, and an inlet side pipe line 22 of the regenerative motor 21 is branched and connected to motor side pipe lines 14 and 15 via a regenerative switching valve 23. The left side and the right side regenerative lines 24, 25 are connected to the tank T on the outlet side.

  The regenerative switching valve 23 is switched and controlled between neutral, left-turning regeneration and right-turning regeneration positions a, b, and c by a command from a controller (not shown). When decelerating to the right, the vehicle switches to the right-turning regeneration position c.

  Thus, for example, when the left turn is decelerated, the oil discharged from the turn motor 12 is converted into the left turn side regeneration position of the meter-out side pipe line (right turn pipe line) 15, the left turn side regeneration line 24, and the regeneration switching valve 23. It is introduced into the regenerative motor 21 via b and the motor 21 rotates.

  That is, by driving the regenerative motor 21 with the oil discharged from the turning motor 12, the energy of the oil is converted into rotational energy and regenerated (in this case, regenerated as engine assist force).

JP 2003-120616 A

  A solid line A in FIG. 2 indicates a general override characteristic of the relief valves 16 and 17, that is, a relationship between the relief flow rate Qr and the relief pressure Pr when the regenerative action is not performed (hereinafter referred to as “non-regenerative characteristic”). Show.

  Under this non-regenerative characteristic, the relief pressure Pr increases as the relief flow rate Qr increases as shown in FIG.

  In FIG. 2, Pr1 is a relief pressure at which a sufficient braking force is exhibited during turning deceleration (hereinafter referred to as “brake relief pressure”), and Qr1 is a relief flow rate at which this brake relief pressure Pr1 is generated during non-regeneration (hereinafter referred to as “ Non-regenerative relief flow rate ”).

  However, according to the swing circuit with the regeneration function, the relief flow rate Qr is obtained by subtracting the suction flow rate Qk of the regeneration motor 21 from the discharge flow rate Qs of the swing motor 12.

  That is, compared with the case where there is no regenerative function, the regenerative motor flow rate Qk, and the relief flow rate Qr is, for example, a flow rate smaller than the non-regenerative relief flow rate Qr1 in FIG. 2 (hereinafter referred to as “regenerative relief flow rate”) Qr2. Decrease.

  When the relief pressure (relief pressure during regeneration) generated at the regenerative relief flow rate Qr2 is Pr2, Pr2 <Pr1, and the braking force is reduced by the difference α between the relief pressures Pr1 and Pr2, resulting in insufficient braking. There is a problem that the time required to stop turning becomes longer.

  Although it is conceivable to reduce the regenerative flow rate Qk and increase the relief flow rate Qr by means such as reducing the capacity of the regenerative motor 21, this will reduce the regenerative efficiency.

  Therefore, the present invention provides a control device for a swing type work machine that can achieve both sufficient regeneration efficiency and high braking performance at the time of turning deceleration.

As means for solving the above problems, in the present invention, an engine, a hydraulic pump driven by the engine, a swing motor driven by pressure oil from the hydraulic pump to drive the swing body, and the swing motor A control valve that controls the operation of the revolving motor, a pair of relief valves provided between the pipes on both sides of the revolving motor, a regenerative motor, a regenerative line that guides oil discharged from the revolving motor to the regenerative motor, and A regenerative switching valve that opens and closes the regenerative line, and is configured to revolve the oil by converting the energy of oil into rotational energy by the regenerative motor while performing the revolving brake action by the relief operation of the relief valve at the time of decelerating revolving. In the control device for a swing type work machine, both the relief valves are relieved by an external command signal. Together constituting a variable relief valve characteristic quantities / relief pressure is changed, providing a control means for controlling the variable relief valve, the control means,
(i) Obtaining the discharge flow rate of the swing motor and the suction flow rate of the regenerative motor,
(ii) The relief flow rate is obtained by subtracting the suction flow rate of the regenerative motor from the discharge flow rate of the swing motor,
(iii) A relief flow rate / relief pressure characteristic is commanded to the variable relief valve so that a relief pressure sufficient to perform the turning brake action is obtained at the relief flow rate.

  According to this configuration, at the time of turning deceleration, in order to change the relief flow rate / relief pressure characteristics of the variable relief valve so as to obtain a sufficient relief pressure to perform the turning brake action on the relief flow rate Qr at that time, While ensuring a sufficient regenerative action, it is possible to obtain a turning brake performance equivalent to the case where the regenerative action is not performed.

  In this case, the control means includes a swing motor speed detecting means for detecting the rotational speed of the swing motor and a regenerative motor speed detecting means for detecting the rotational speed of the regenerative motor. It is desirable that the discharge flow rate of the swing motor and the suction flow rate of the regenerative motor are calculated based on each rotation speed and each motor capacity (claim 2).

  In this way, the motor speed is detected by an inexpensive speed detection means, and the flow rate of both the revolving and regenerative motors, that is, the revolving motor discharge flow rate and the regenerative motor intake flow rate are calculated from this motor speed. Compared with the case of detecting directly, the equipment cost can be reduced.

  In addition, since it is possible to detect whether or not the vehicle is decelerating based on the change in the rotation motor speed, that is, the rotation motor speed detection means can be used as the rotation deceleration detection means. The equipment cost can be further reduced as compared with the case where the pressure on both sides of the meter-out is detected by the pressure sensor to determine whether or not the vehicle is decelerating.

  According to the present invention, sufficient regenerative efficiency and high braking performance can be achieved at the time of turning deceleration.

It is a circuit block diagram of the control apparatus which concerns on embodiment of this invention. It is a figure which shows the general override characteristic of a relief valve, and the relief pressure characteristic after adjustment by embodiment. It is a flowchart for demonstrating the effect | action of embodiment. 1 is a schematic side view of a hydraulic excavator that is an example to which the present invention is applied. It is a circuit block diagram which shows a prior art.

  An embodiment of the present invention will be described with reference to FIGS.

  The embodiment is applied to a hydraulic excavator.

  In the following embodiments, the following points are the same as those of the prior art shown in FIG.

  (A) Between the hydraulic pump 10 as a hydraulic source driven by the engine 11 and the tank T and the turning motor 12, neutral, left-turning and right-turning positions a by a pilot pressure from a remote control valve (not shown) A control valve 13 that is a hydraulic pilot type switching valve that is switched between B and C is provided, and supply and discharge of pressure oil to and from the swing motor 12 (rotation / stop of the swing motor 12, rotation direction, (Rotational speed) is controlled.

  (B) Relief valves 26 and 27 as brake valves are provided opposite to each other between the two turning pipes 14 and 15, and in parallel therewith, a check valve for anti-cavitation (for preventing cavitation = oil suction) 18 and 19 are provided in an opposing arrangement, and the outlet side of both relief valves 26 and 27 and the inlet side of both check valves 18 and 19 are connected by a communication passage 20, and this communication passage 20 is connected to the tank T. Point to be.

  (C) When the control valve 13 returns from the left turning position B to the neutral position A, for example, the turning motor 12 and both turning pipes 14 and 15 are disconnected from the pump 10 and the tank T, and supply of pressure oil to the turning motor 12 is performed. And the point where the return of the oil of the tank T from the turning motor 12 stops.

  (D) In this case, since the swing motor 12 tries to continue the left turn due to the inertia of the upper swing body 2, pressure is generated in the right turn pipeline (meter-out side pipeline) 15 on the outflow side, and this is constant. When the value is reached, the relief valve 26 on the right side of the figure opens and the oil in the right turning pipe 15 passes through the relief valve 26 -the communication path 20 -the check valve 18 on the left side of the figure and the left turning pipe (meter-in side pipe) ) The point that enters 14 and flows into the turning motor 12.

  (E) At this time, if the left turning pipeline 14 tends to have a negative pressure, tank oil is sucked up from the communication passage 20 to the left turning pipeline 14 via the check valve 18 to prevent cavitation.

  (F) A variable capacity type regenerative motor (hydraulic motor) 21 is connected to the engine 11, and an inlet side pipe line 22 of the regenerative motor 21 branches to motor side pipe lines 14 and 15 via a regenerative switching valve 23. A point where the outlet side is connected to the tank T on both the left turning side and right turning side regenerative lines 24 and 25 connected.

  (G) The regeneration switching valve 23 is switched and controlled by the controller 28 between the neutral, left-turning regeneration, and right-turning regeneration positions a, b, and c.

  (H) The regenerative switching valve 23 is switched from the left turn side regenerative position b during left turn deceleration and to the right turn side regenerative position c during right turn deceleration, thereby discharging from the turn motor 12 during left turn deceleration, for example. Is introduced into the regenerative motor 21 via the meter-out side line (right turn line) 15, the left turn side regeneration line 24, and the left turn side regeneration position b of the regenerative switching valve 23. By driving the regenerative motor 21 with the oil rotating from the turning point, that is, the oil discharged from the turning motor 12, the energy of the oil is converted into rotational energy and regenerated (in this case, regenerated as engine assist force). Point.

  In the embodiment, as the relief valves 26 and 27, instead of the conventional fixed relief valves 16 and 17 in which the set pressure is constant, the relief flow rate / relief pressure characteristic (spring) is determined by a command signal (electrical signal) from the controller 28. An electromagnetic variable relief valve that changes the setting) is used.

  The characteristics of the relief flow / relief pressure when there is no command from the controller 28 to the variable relief valves 26 and 27 (when the regeneration action is not performed) are the non-regenerative characteristics A shown by the solid line in FIG. .

  As described above, the braking relief pressure Pr1 is generated at the relief flow rate (regeneration relief flow rate) Qr1 at this time, and a sufficient turning brake force is exhibited by the braking relief pressure Pr1.

  On the other hand, when the regenerative action is activated during turning deceleration, the relief flow rate Qr decreases from the non-regenerative relief flow rate Qr1 to the regenerative flow rate Qr2, and the relief pressure Pr decreases to Pr2 corresponding to Qr2. If it remains, sufficient braking force cannot be obtained.

  Therefore, a command signal for changing the spring setting so that the brake relief pressure Pr2 is generated from the controller 28 to the relief valves 26 and 27 at the regeneration relief flow rate Qr2 at the time of turning deceleration, specifically, the non-regenerative characteristics A Is shifted upward, and a signal for changing to the regeneration characteristic B shown by a broken line in FIG. 2 is sent.

  Further, as a detecting means, a turning motor speed sensor 29 such as a gyro sensor for detecting the rotation speed of the turning motor 12 and a regenerative motor speed sensor 30 for detecting the rotation speed of the regenerative motor 21 are provided. Is input to the controller 28.

  That is, the controller 28 and the sensors 29 and 30 constitute “control means” in the claims.

  Furthermore, a regenerative motor regulator 31 for controlling the tilt of the regenerative motor 21 is provided, and the regulator 31 is controlled by the controller 28.

  The contents of control by the control means will be described in detail with reference to the flowchart of FIG.

  After the start of control, in step S1, the swing motor speed is calculated from the speed signal from the swing motor speed sensor 29, and in step S2, it is determined whether or not the vehicle is in a turn deceleration state from the change in the turn motor speed.

  If NO (not during turning deceleration), an off command is issued to the regenerative switching valve 23 in step S3, and the tilt of the regenerative motor 21 is minimized with respect to the regenerative motor regulator 31 in step S4. Command to be issued.

  As a result, the regenerative switching valve 23 is set to the neutral position a and the introduction of oil to the regenerative motor 21 is prevented, and the regenerative motor 21 is set to the minimum tilt and its follow-up resistance is minimized.

  Further, in the following step S5, a command is issued to the relief valves 26 and 27 to set the characteristic to the non-regenerative characteristic A shown in FIG. 3, and the process returns to step S1.

  On the other hand, if YES in step S2 (during deceleration of the turn), the process proceeds to step S6, where the regenerative switching valve 23 is turned on (switching command to the left turn side regenerative position b or right turn side regenerative position c). In step S7, a tilt increase command is issued to the regenerative motor regulator 31.

  As a result, the regenerative switching valve 23 is switched to the regenerative position b or c, the tilt of the regenerative motor 21 is increased, and the regenerative action by the regenerative motor 21 is started.

  Next, in step S8, the discharge flow rate Qs of the motor 12 is determined from the tilt (known) and rotational speed of the swing motor 12, and in step S9, the motor 21 is determined from the tilt (command value) and rotational speed of the regenerative motor 21. The suction flow rate Qk is calculated respectively.

In step S10, the relief flow rate Qr (relief relief flow rate Qr2) of the relief valves 26 and 27 is
Qr2 = Qs−Qk
Is calculated by

  In step S11, a regeneration characteristic B indicated by a broken line in FIG. 3 is commanded as the relief flow rate / relief pressure characteristics of the variable relief valves 26 and 27, and the process returns to step S1.

  With this control, a braking relief pressure Pr1 can be generated and a sufficient braking force can be applied while performing a regenerative action during turning deceleration. That is, sufficient regeneration efficiency and high brake performance can be achieved at the same time.

  In this case, the speeds of both the revolving and regenerating motors 12 and 21 are detected by inexpensive speed sensors 29 and 30, and the flow rates of the both motors 12 and 21 from this motor speed, that is, the revolving motor discharge flow rate Qs and the regenerative motor intake flow rate Qk. Therefore, the equipment cost can be reduced as compared with the case where the flow rate is directly detected by an expensive flow meter.

  In addition, since it is possible to detect whether or not the vehicle is decelerating based on the change in the swing motor speed, that is, the swing motor speed sensor 29 can also be used as a swing deceleration detecting means. The equipment cost can be further reduced as compared with the case where the pressure on both sides of the meter-out is detected by the pressure sensor and it is determined whether or not the vehicle is turning and decelerating.

Other embodiments
(1) In the above embodiment, the electromagnetic variable relief valves 26 and 27 are used and directly controlled by an electric signal from the controller 28. However, a hydraulic pilot type variable relief valve is used and the hydraulic pilot valve is interposed. The relief valves 26 and 27 may be controlled.

  (2) Although the variable displacement hydraulic motor is used as the regenerative motor 21 in the above embodiment, a fixed displacement hydraulic motor may be used.

  (3) The present invention is not limited to hydraulic excavators, and can be widely applied to hydraulic swivel working machines including dismantling machines and crushers.

DESCRIPTION OF SYMBOLS 1 Lower traveling body 2 Upper revolving body 10 Hydraulic pump 11 Engine 12 Turning motor 13 Control valve 14,15 Motor both-side pipe 21 Regenerative motor 22 Inlet side pipe 23 Regenerative switching valve 24,25 Regenerative line 26,27 Variable relief valve 28 Controller constituting control means 29 Same as above, rotation motor speed sensor 30 Same as above, regenerative motor speed sensor

Claims (2)

An engine, a hydraulic pump driven by the engine, a swing motor driven by pressure oil from the hydraulic pump to drive the swing body, a control valve for controlling the operation of the swing motor, and the swing motor A revolving valve is provided with a pair of relief valves provided between the pipes on both sides, a regenerative motor, a regenerative line that guides oil discharged from the revolving motor to the regenerative motor, and a regenerative switching valve that opens and closes the regenerative line. In the control device for a swing type work machine configured to perform a swing braking action by a relief operation of the relief valve during deceleration, and convert the energy of oil into rotational energy by the regenerative motor and regenerate, the both reliefs The valve is a variable relief valve that changes the relief flow rate / relief pressure characteristics in response to an external command signal. Together constitute, it provided a control means for controlling the variable relief valve, the control means,
(i) Obtaining the discharge flow rate of the swing motor and the suction flow rate of the regenerative motor,
(ii) The relief flow rate is obtained by subtracting the suction flow rate of the regenerative motor from the discharge flow rate of the swing motor,
(iii) The relief flow rate / relief pressure characteristics are commanded to the variable relief valve so as to obtain a relief pressure sufficient to perform the turning brake action at the relief flow rate. A control device for a rotating work machine.   The control means includes a swing motor speed detecting means for detecting the rotational speed of the swing motor, and a regenerative motor speed detecting means for detecting the rotational speed of the regenerative motor, and each detected rotational speed of the swing motor and the regenerative motor is detected. 2. The control device for a swing type work machine according to claim 1, wherein a discharge flow rate of the swing motor and a suction flow rate of the regenerative motor are calculated based on the motor capacity.

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