JP2012047252A - Warming-up operation control device in hydraulic working machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently perform warming-up operation for raising the temperature of a hydraulic fluid in a short time, in a state of holding a control valve in a neutral position, in a hydraulic working machine.SOLUTION: When the temperature of the hydraulic fluid is less than the set temperature and a hydraulic lock lever is operated for locking, the warming-up operation is performed by maximizing a discharge flow rate of first and second hydraulic pumps in a state of holding the control valve in the neutral position, by maximizing capacity of the first and second hydraulic pumps, and maximizing an engine speed, by outputting a control command to first and second solenoid inverse proportional pressure reducing valves 10 and 11 and an engine controller 16 from a controller 9.

Description

  The present invention relates to a warm-up operation control device in a hydraulic work machine such as a hydraulic excavator or a hydraulic crane.

Generally, hydraulic work machines such as hydraulic excavators and hydraulic cranes not only exhibit the performance of hydraulic equipment such as hydraulic pumps and hydraulic actuators, but also have poor responsiveness when the temperature of the hydraulic oil is lower than the optimum temperature. As a result, operability is impaired. For this reason, in winter and cold regions, warm-up operation is usually performed before the start of work, but as a warm-up operation for raising the operating oil temperature in as short a time as possible, the operator operates the operating lever to stroke the hydraulic actuator. After moving to the end, a method of relieving the hydraulic oil by continuing to operate the operation lever and increasing the temperature of the hydraulic oil with the amount of heat generated by the relief is widely adopted. However, such a warm-up operation requires a heavy burden on the operator because the operation lever must be operated continuously, or the control valve for the hydraulic actuator that has been operated remains switched to the operating position and the temperature is increased by the relief. When exposed to the oil, the spool portion exposed to the high temperature may thermally expand to cause a thermal shock.
Therefore, conventionally, during warm-up operation, the control valve is switched to the operating position by a signal output from the controller in the neutral state of the operating lever, so that the hydraulic oil can be relieved without the operator operating the operating lever. (For example, refer to Patent Document 1) and, if the temperature of the hydraulic oil is equal to or lower than a predetermined temperature, a technique for raising the temperature of the hydraulic oil by temporarily increasing the discharge amount of the hydraulic pump (for example, Patent Reference 2) is proposed.

JP 11-125217 A Japanese Patent Laid-Open No. 2003-239907

  However, although the thing of the said patent document 1 relieves hydraulic oil in the state which switched the control valve to the operating position, although the burden that an operator continues operating an operation lever during warming-up operation is lost, it is thermal shock. There is a problem that the fear of occurrence cannot be avoided. On the other hand, although the thing of patent document 2 can avoid the burden of an operator and the fear of a thermal shock, when this operator operates an operation lever during a warming-up operation, the discharge amount of a hydraulic pump will increase. For this reason, there is a problem that the operating speed of the hydraulic actuator becomes faster than the speed according to the operation amount of the operation lever. Further, the discharge flow rate of the hydraulic pump increases and decreases in proportion to the pump rotational speed, and the rotational speed of the hydraulic pump driven by the engine is determined by the engine rotational speed. In some situations, the engine idling speed is reduced to the idling speed by the auto idling control system, so if the operating lever is not operated, the engine speed during the warm-up operation is idling speed. However, there is a problem in that the discharge flow rate of the hydraulic pump cannot be increased so much that the warm-up operation takes time, and there is a problem to be solved by the present invention.

  The present invention has been created in view of the above circumstances and has been created for the purpose of solving these problems. The invention of claim 1 is driven by an engine, an engine controller for controlling the engine, and the engine. A variable displacement hydraulic pump, a hydraulic actuator that uses the hydraulic pump as a hydraulic source, and a control valve that operates to perform oil supply control from the hydraulic pump to the hydraulic actuator based on the operation of the operation tool for the hydraulic actuator The pump displacement control means for controlling the displacement of the hydraulic pump by introducing the negative control pressure generated according to the center bypass passage amount of the control valve to the displacement capacity means of the hydraulic pump, and the hydraulic locking operation tool are locked. A hydraulic lock that holds the control valve in a neutral position without supplying hydraulic oil to the hydraulic actuator when In a hydraulic work machine comprising a step, hydraulic oil temperature detection means for detecting the temperature of hydraulic oil, lock operation detection means for detecting whether or not the hydraulic lock operating tool is locked, and the negative control pressure In place of this, a solenoid valve that outputs the signal pressure that maximizes the capacity of the hydraulic pump to the capacity variable means of the hydraulic pump is provided, the temperature of the hydraulic oil is lower than the set temperature, and the hydraulic locking operation tool is locked. If it is, warm-up operation control that outputs a control command for signal pressure output to the solenoid valve to maximize the capacity of the hydraulic pump, and outputs a control command to the engine controller to maximize the engine speed A warming-up operation control apparatus for a hydraulic work machine, characterized in that a means is provided.

  According to the invention of claim 1, the discharge flow rate of the hydraulic pump during the warming-up operation is maximized, so that the operating oil can be efficiently heated in a short time, thereby improving the working efficiency. Can contribute. In addition, the warm-up operation is performed when the hydraulic lock lever is locked, that is, when the control valve is held in the neutral position by the hydraulic lock means, and the control valve may cause a thermal shock. In addition to avoiding this, even if the operator operates the actuator for the hydraulic actuator, no hydraulic oil is supplied to the hydraulic actuator. When the tool is operated, it is possible to reliably avoid a problem that the hydraulic actuator operates at a high speed that does not correspond to the operation amount of the operation tool.

It is a hydraulic circuit diagram of a hydraulic excavator. It is a block diagram which shows the input / output of a controller. It is a flowchart figure which shows the control procedure of warm-up operation control.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a hydraulic circuit of a hydraulic excavator which is an example of a hydraulic work machine provided with the warm-up operation control device of the present invention. In FIG. 1, E is driven by the engine, and 1 and 2 are driven by the engine E. First and second hydraulic pumps, 3 is a pilot pump, 4 is an oil tank, A1 to A6 are hydraulic actuators (left and right traveling motors, swing motors, boom cylinders, stick cylinders, bucket cylinders, etc.) provided in the hydraulic excavator, B1 ˜B6 are control valves that respectively perform oil supply / discharge control for the hydraulic actuators A1 to A6.

  The first and second hydraulic pumps 1 and 2 are variable displacement hydraulic pumps having displacement variable means 1a and 2a. In the present embodiment, the first hydraulic pump 1 includes hydraulic actuators A1 to A3. The second hydraulic pump 2 is a hydraulic source for the hydraulic actuators A4 to A6. The first and second hydraulic pumps 1 and 2 correspond to the hydraulic pump of the present invention.

  The control valves B1 to B6 are three-position switching spool valves having pilot ports Bx and By. When the pilot pressure is not input to both pilot ports Bx and By, the hydraulic actuators A1 to A6 The pilot oil is supplied to the pilot port Bx or By to move the spool, and the discharged oil of the first and second hydraulic pumps 1 and 2 is discharged. It is configured to switch to the operating position X or Y supplied to the hydraulic actuators A1 to A6.

  Further, C1 to C6 are pilot valves that output pilot pressure to the pilot ports Bx and By of the control valves B1 to B6 based on the operation of a hydraulic actuator operation tool (not shown, operation lever, operation pedal, etc.). Thus, the pilot pressure output from the pilot valves C1 to C6 is increased or decreased in accordance with the operation amount of the hydraulic actuator operation tool. The movement strokes of the spools of the control valves B1 to B6 increase / decrease in accordance with the pilot pressure output from the pilot valves C1 to C6. Further, the control valves B1 to B6 increase / decrease in accordance with the movement strokes of the spools. The pressure oil supply flow rate to the hydraulic actuators A1 to A6 is controlled to increase or decrease.

  On the other hand, the control valves B1 to B6 are supplied with oil discharged from the first and second hydraulic pumps 1 and 2 via first and second negative control valves (hereinafter abbreviated as negative control valves) 5 and 6. 4 is formed. The flow path of the center bypass Bs is set so that the opening area is maximum when the control valves B1 to B6 are in the neutral position N, and the opening area becomes smaller as the moving stroke of the spool becomes larger. The pressure on the inlet side of the first and second negative control valves 5 and 6 generated according to the passing amount of Bs is the first and second negative control lines (hereinafter referred to as negative control pressure) as negative control pressure (hereinafter referred to as negative control pressure). Lines (abbreviated as lines) 7 and 8 are input to the capacity variable means 1a and 2a of the first and second hydraulic pumps 1 and 2, respectively. Then, the capacity variable means 1a, 2a of the first and second hydraulic pumps 1, 2 can change the capacity (displacement volume per rotation) of the first, second hydraulic pumps 1, 2 when the input negative control pressure is high. The pump volume control is performed so that the capacity is increased as the negative control pressure is reduced. The center bypass Bs, the first and second negative control valves 5 and 6, and the first and second negative control lines 7 and 8 formed in the control valves B1 to B6 constitute the pump displacement control means of the present invention.

  Further, the first and second negative control lines 7 and 8 have first and second electromagnetic inverse proportional pressure reducing valves (corresponding to the electromagnetic valves of the present invention) that operate based on a control command from the controller 9 as will be described later. ) 10, 11 are arranged. The first and second electromagnetic inverse proportional pressure reducing valves 10 and 11 correspond to the passage amount of the center bypass Bs of the control valves B1 to B6 when a control command for solenoid non-excitation is output from the controller 9. The generated negative control pressure is output as it is to the capacity variable means 1a, 2a of the first and second hydraulic pumps 1, 2 without being reduced. On the other hand, when a control command for solenoid excitation is output from the controller 9, the first and second electromagnetic inverse proportional pressure reducing valves 10 and 11 reduce the negative control pressure to the tank pressure (approximately “0 (zero)” Mpa). The tank pressure is output to the capacity variable means 1a, 2a as a signal pressure that maximizes the capacity of the first and second hydraulic pumps 1, 2. That is, the solenoid excitation control command output from the controller 9 to the first and second electromagnetic inverse proportional pressure reducing valves 10 and 11 is a signal pressure output command that maximizes the capacity of the first and second hydraulic pumps 1 and 2. Then, when the signal pressure is output from the first and second electromagnetic inverse proportional pressure reducing valves 10 and 11 to the capacity varying means 1a and 2a, the capacity of the first and second hydraulic pumps 1 and 2 is maximized. It is controlled to become.

  The pilot pressure output from the pilot valves C1 to C6 is a pilot pump 3, and a pilot pump oil passage 12 from the pilot pump 3 to the pilot valves C1 to C6 has a hydraulic lock lever (not shown). However, there is provided a hydraulic lock electromagnetic switching valve 13 that switches in connection with the operation of the hydraulic lock operating tool of the present invention. The hydraulic lock exchange switching valve 13 is a two-position switching valve, and when the hydraulic lock lever is operated to the locked position (locking operation), the oil discharged from the pilot pump 3 is not supplied to the pilot valves C1 to C6. Although it is located at the lock position N, it is configured to switch to the release position X where the discharge oil of the pilot pump 3 is supplied to the pilot valves C1 to C6 by operating the hydraulic lock lever to the release position (release operation). Has been. Thus, when the hydraulic lock lever is locked, the hydraulic lock electromagnetic switching valve 13 is positioned at the neutral position N and the discharge oil of the pilot pump 3 is not supplied to the pilot valves C1 to C6. Even if the operation tool is operated, pilot pressure is not output from the pilot valves C1 to C6, so that the control valves B1 to B6 are held at the neutral position N where no hydraulic oil is supplied to the hydraulic actuators A1 to A6. Yes. On the other hand, in a state where the hydraulic lock lever is released, the hydraulic lock electromagnetic switching valve 13 is switched to the release position X, so that the discharge oil of the pilot pump 3 is supplied to the pilot valves C1 to C6. A pilot pressure is output from the pilot valves C1 to C6 based on the operation of the actuator operation tool, whereby the control valves B1 to B6 are switched to the operating positions X or Y, and pressure oil is supplied to the hydraulic actuators A1 to A6. It is like that. The hydraulic lock electromagnetic switching valve 13 constitutes the hydraulic lock means of the present invention.

  On the other hand, the controller 9 corresponds to the warming-up operation control means of the present invention. As shown in the block diagram of FIG. 2, the controller 9 detects the temperature of the operating oil in the oil tank 4 on the input side. Detection sensor (corresponding to hydraulic oil temperature detection means of the present invention) 14 and lock operation detection means (for example, a limit switch for detecting the lock position of the hydraulic lock lever) 15 for detecting whether or not the hydraulic lock lever is locked 15 And the first and second electromagnetic inverse proportional pressure reducing valves 10 and 11 and the engine controller 16 are connected to the output side.

  Here, the engine controller 16 controls the start and stop of the engine E based on the operation of an engine key switch (not shown), and the number of revolutions of the engine E is set by the accelerator operating tool 17. The fuel injection amount is controlled so that the controller 9 executes the command from the controller 9 in preference to the setting of the accelerator operating tool 17 when the controller 9 outputs the maximum engine speed command as will be described later. To do. The accelerator operating tool 17 is an operating tool for an operator to arbitrarily set the engine speed according to work, and is constituted by, for example, an accelerator dial or an accelerator lever.

  The controller 9 performs warm-up operation control for raising the temperature of the hydraulic oil. The warm-up operation control will be described with reference to the flowchart of FIG. First, when the system is started as the engine E is started, it is determined whether or not the hydraulic oil temperature T detected by the hydraulic oil temperature detection sensor 14 is lower than the set temperature Ts (T <Ts?) (Step S1). The set temperature Ts is a temperature set in advance as a threshold value of the hydraulic oil temperature when the warm-up operation is executed. The operator uses a dial or a monitor device (not shown) according to the season, the temperature at the work site, or the like. It can be set arbitrarily.

  If “YES” in the determination in step S1, that is, if the hydraulic oil temperature T is lower than the set temperature Ts, whether the hydraulic lock lever is continuously locked based on the detection signal from the lock operation detection means 15. It is determined whether or not (step S2). On the other hand, if the determination in step S1 is “NO”, that is, if the hydraulic oil temperature T is equal to or higher than the set temperature Ts, the determination in step S1 is repeated.

  If “YES” in the determination in step S2, that is, if the hydraulic lock lever is locked, the controller 9 outputs an engine speed maximum command to the engine controller 16 so as to maximize the engine speed (step). S3). Thus, the engine controller 16 controls the engine E to maximize the engine speed in preference to the engine speed set by the accelerator operating tool 17.

  Further, the controller 9 outputs a solenoid excitation command to the first and second electromagnetic inverse proportional pressure reducing valves 10 and 11 (step S4). Thereby, the first and second electromagnetic inverse proportional pressure reducing valves 10 and 11 reduce the negative control pressure to the tank pressure and output it to the capacity variable means 1a and 2a of the first and second hydraulic pumps 1 and 2, respectively. The tank pressure output from the first and second electromagnetic inverse proportional pressure reducing valves 10 and 11 is the signal pressure that maximizes the capacity of the first and second hydraulic pumps 1 and 2 as described above. The capacities of the second hydraulic pumps 1 and 2 are controlled to be maximized.

  After the processes in steps S3 and S4, it is determined whether the hydraulic oil temperature T is equal to or higher than the set temperature Ts (T ≧ Ts?) (Step S5). If “NO” in the determination in step S5, that is, if the hydraulic oil temperature T is lower than the set temperature Ts, the process returns to the determination in step S2.

  On the other hand, if “YES” in the determination in step S5, that is, if the hydraulic oil temperature T is equal to or higher than the set temperature Ts, or “NO” in the determination in step S2, that is, if the hydraulic lock lever is not locked, The controller 9 stops outputting the engine speed maximum command to the engine controller 16 (step S6). As a result, the engine controller 16 controls the engine E so as to obtain the engine speed set by the accelerator operating tool 17.

  Further, the controller 9 outputs a solenoid non-excitation command to the first and second electromagnetic inverse proportional pressure reducing valves 10 and 11 (step S7). As a result, the first and second electromagnetic inverse proportional pressure reducing valves 10 and 11 output the negative control pressure to the capacity variable means 1a and 2a of the first and second hydraulic pumps 1 and 2 without reducing the negative control pressure. Thus, the capacities of the first and second hydraulic pumps 1 and 2 are increased / decreased controlled according to the negative control pressure generated according to the passage amount of the center bypass Bs of the control valves B1 to B6.

  That is, the controller 9 maximizes the capacities of the first and second hydraulic pumps 1 and 2 when the hydraulic oil temperature T is lower than the set temperature Ts and the hydraulic lock lever is locked. Warm-up operation control is performed to maximize the number of revolutions of E. As a result, the first and second hydraulic pumps 1 and 2 discharge the maximum amount of hydraulic fluid, and the maximum flow rate of hydraulic fluid is the center bypass Bs of the control valves B1 to B6 at the neutral position N and the first and second negative controls. It passes through the valves 5 and 6 and is collected in the oil tank 4. Then, the hydraulic oil is heated by the amount of heat generated by the pressure loss in the valves and pipes until it is recovered, and thus the warming-up operation is performed to raise the temperature of the hydraulic oil. This warm-up operation is stopped when the hydraulic oil temperature T becomes equal to or higher than the set temperature Ts or when the hydraulic lock lever is released. When the warm-up operation is stopped, the capacities of the first and second hydraulic pumps 1 and 2 are controlled according to the negative control pressure, and the engine speed is set to the speed set by the accelerator operating tool 17. To be controlled.

  In the present embodiment configured as described, the hydraulic excavator 1 includes a hydraulic oil temperature detection sensor 14 that detects the temperature of hydraulic oil and a hydraulic lock lever locking operation as a warming-up operation control device for performing a warm-up operation. The lock operation detecting means 15 for detecting the presence or absence, and the signal pressure (tank pressure) for maximizing the capacity of the first and second hydraulic pumps 1 and 2 in place of the negative control pressure are There are provided first and second electromagnetic inverse proportional pressure reducing valves 10 and 11 that output to the capacity variable means 1a and 2a, and a controller 9 that performs warm-up operation control. The first and second electromagnetic inverse proportional pressure reducing valves 10 to maximize the capacity of the first and second hydraulic pumps 1 and 2 when the temperature is lower than the set temperature Ts and the hydraulic lock lever is locked. 11 signal pressure It outputs a control command of the force (control command of the solenoid excitation), and, thus performing the warm-up operation control to output an engine speed up command to the engine controller 16 to maximize the engine speed.

  Thus, when the temperature T of the hydraulic oil is lower than the set temperature Ts and the hydraulic lock lever is locked, the hydraulic oil is raised to the set temperature Ts by the warm-up operation control performed by the controller 9. While the warming-up operation is performed automatically, and during the warming-up operation, the capacities of the first and second hydraulic pumps 1 and 2 are maximized and the engine speed is maximized. The discharge flow rates of 1 and 2 are maximized and are heated by the amount of heat generated due to the pressure loss until the maximum amount of hydraulic oil is recovered in the oil tank 4. As a result, the warm-up operation can be performed efficiently, the time required for the warm-up operation can be shortened, and the work efficiency can be improved.

  Furthermore, since the warming-up operation is performed when the hydraulic lock lever is locked, the control valves B1 to B6 are held at the neutral position N during the warming-up operation. The hydraulic oil passes through the center bypass Bs of the control valves B1 to B6. Since the flow path of the center bypass Bs when the control valves B1 to B6 are located at the neutral position N is sufficiently large, the warm-up operation is performed. Therefore, there is no possibility that the control valves B1 to B6 cause a thermal shock. In addition, when the hydraulic lock lever is locked, even if the operator operates the hydraulic actuator operation tool, no pressure oil is supplied to the hydraulic actuators A1 to A6. Even if the discharge flow rate of the second hydraulic pumps 1 and 2 is the maximum, when the operation tool for the hydraulic actuator is operated, the hydraulic actuator is operated at a high speed that does not correspond to the operation amount of the operation tool. Can be avoided reliably. On the other hand, when the operator wants to stop the warm-up operation on his / her own will, the warm-up operation is stopped by releasing the hydraulic lock lever.

  Needless to say, the present invention is not limited to the above-described embodiment. For example, as a solenoid valve that outputs a signal pressure that maximizes the capacity of the hydraulic pump to the capacity varying means, the negative control pressure can be varied. It is also possible to use a two-position switching solenoid valve that switches between a neutral position leading to the means and an operating position leading the tank pressure to the capacity variable means of the hydraulic pump. Incidentally, in the above embodiment, an electromagnetic inverse proportional pressure reducing valve is used as an electromagnetic valve that outputs a signal pressure that maximizes the capacity of the hydraulic pump to the capacity varying means. By controlling the input current variably, it is possible to increase or decrease the signal pressure output to the capacity variable means of the hydraulic pump, thereby increasing or decreasing the discharge flow rate of the hydraulic pump according to the level of hydraulic oil temperature. Is also possible.

  In the above embodiment, the first and second hydraulic pumps are provided as the hydraulic pumps, and the first and second negative control valves, the first and second negative control lines, the first and second Although two electromagnetic inverse proportional pressure reducing valves are provided, the present invention can be similarly implemented even if the number of hydraulic pumps is one or three or more. Furthermore, the present invention is not limited to hydraulic excavators, and can of course be implemented in various hydraulic work machines that require warm-up operation.

  INDUSTRIAL APPLICABILITY The present invention can be used in a warm-up operation control device for raising the temperature of hydraulic oil in a hydraulic work machine such as a hydraulic excavator or a hydraulic crane.

1, 2 1st, 2nd hydraulic pump 1a, 2a Capacity variable means 5, 6 1st, 2nd negative control valve 7, 8 1st, 2nd negative control line 9 Controller 10, 11 1st, 2nd electromagnetic reverse Proportional pressure reducing valve 13 Hydraulic lock electromagnetic switching valve 14 Hydraulic oil temperature detection sensor 15 Lock operation detection means 16 Engine controller A1 to A6 Hydraulic actuator B1 to B6 Control valve Bs Center bypass E Engine

Claims (1)

  An engine, an engine controller for controlling the engine, a variable displacement hydraulic pump driven by the engine, a hydraulic actuator using the hydraulic pump as a hydraulic source, and a hydraulic pump based on the operation of the hydraulic actuator operation tool. A control valve that operates to control oil supply to the hydraulic actuator, and a pump that controls the capacity of the hydraulic pump by introducing a negative control pressure generated according to the center bypass passage amount of the control valve to the capacity variable means of the hydraulic pump In a hydraulic work machine comprising: a capacity control means; and a hydraulic lock means for holding the control valve in a neutral position where pressure oil is not supplied to the hydraulic actuator when the hydraulic lock operating tool is locked. Hydraulic oil temperature detecting means for detecting the temperature of the hydraulic oil A lock operation detecting means for detecting the presence or absence of a hydraulic operation and an electromagnetic valve for outputting a signal pressure for maximizing the capacity of the hydraulic pump to the capacity varying means of the hydraulic pump instead of the negative control pressure. When the temperature is lower than the set temperature and the hydraulic lock operating tool is locked, a signal pressure output control command is output to the solenoid valve to maximize the capacity of the hydraulic pump, and the engine rotation A warming-up operation control device for a hydraulic work machine, characterized by comprising warming-up operation control means for outputting a control command to an engine controller to maximize the number.

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