JP5735407B2 - Inertial body swing back prevention device - Google Patents

Description

  The present invention relates to an inertia body anti-swaying device for preventing back-swing that occurs when a hydraulic actuator that drives an inertial body such as an upper swing body, a boom, and an arm of a hydraulic excavator is stopped.

  A hydraulic motor that drives an inertial body such as a swivel body of a hydraulic excavator has a first port and a second port. A first pipe and a second pipe are connected to the first port and the second port, and the hydraulic oil discharged from the hydraulic pump passes through either the first pipe or the second pipe via the direction control valve. The hydraulic motor rotates in one direction by being supplied to one of the pipes and discharging hydraulic oil from the other pipe through the direction control valve to the tank.

  Such a hydraulic motor is rotated by the inertial force of the inertial body even after the driving force by the hydraulic oil is lost once it starts to rotate, so it is difficult to stop at a predetermined position.

  Further, when the hydraulic oil supplied to the first port or the second port is shut off by operating the direction control valve in order to stop the rotated hydraulic motor, the hydraulic oil in the supply side pipeline and the discharge side The hydraulic fluid in the pipeline is sealed in the pipeline by a direction control valve. As described above, since the hydraulic motor is rotated by the inertial force (inertial energy) of the inertial body, the hydraulic oil in the supply-side pipe line is disconnected from the tank side by the pumping action. It will be discharged to the road, and the hydraulic oil pressure will be raised abnormally.

  Therefore, the first pipe and the second pipe are connected via a safety valve, and hydraulic oil discharged from one port by the pump action of such a hydraulic motor is caused to flow out to the other port by the safety valve operation. Yes. As a result, abnormal high pressure of the hydraulic oil is prevented and the hydraulic motor is braked so that it can be smoothly stopped.

  However, since the set pressure of the safety valve is generally set to be quite high, even if the hydraulic motor stops, hydraulic oil that is compressed below the set pressure of the safety valve remains in the discharge side as elastic energy. become. As a result, when the hydraulic motor is stopped, this elastic energy reverses the hydraulic motor and reverses the inertial body. As a result, the hydraulic motor further rotates with the inertial energy generated by the inertial body, and this time, the hydraulic oil in the opposite pipe is compressed and converted into elastic energy. In this way, the hydraulic motor stops while causing a swing back phenomenon that repeats rotation by inertial energy and reverse rotation by elastic energy.

  In order to prevent such a swing-back phenomenon, there is a type in which an inversion prevention valve for allowing compressed oil to escape to a tank or a low-pressure line is provided in the first line and the second line (for example, Patent Documents). 1). Due to the throttling effect of the reverse prevention valve, elastic energy is consumed to prevent the hydraulic motor from swinging back.

JP 57-25570 A

  When the above-described swing-back phenomenon occurs, the hydraulic oil has a high elastic coefficient. Therefore, even if the hydraulic oil in the discharge side pipe has a capacity of, for example, several tens of cc, the pressure is, for example, around 30 Mpa. Can be very expensive. Since the above-described inversion prevention valve allows the high-pressure hydraulic oil to escape to the low-pressure port, there is a problem that it is very difficult to control the opening / closing timing and the opening amount.

  For example, when the opening amount is too large or when the closing timing of the reverse prevention valve is late, a large amount of hydraulic oil is discharged to the low pressure port, tank, or the like. As a result, the elastic energy having a braking effect is reduced, and the stopping distance of the inertial body is unnecessarily increased. On the other hand, when the opening amount is too small or when the closing timing of the reverse prevention valve is early, the hydraulic oil is prevented from being discharged, so that the elastic energy is not released easily and the time until it is consumed becomes long. As a result, the rocking action by the hydraulic oil frequently occurs.

  Further, when the inertial body is a swing body of a hydraulic excavator, the moment of inertia may change depending on the posture of the boom or arm disposed on the swing body. For this reason, even if it is a case where the stop performance of the turning body which has a certain moment of inertia can be ensured by control of the inversion prevention valve, the stop performance of the turning body may change depending on the posture of the boom or arm.

  The present invention has been made based on the above-described matters, and an object of the present invention is to provide an inertia body anti-swaying prevention device that can reliably prevent the inertia body from swinging back and shorten the stopping distance. is there.

In order to achieve the above object, a first invention provides a hydraulic pump, a hydraulic actuator for driving an inertial body, a first pipe line having one end connected to a first port of the hydraulic actuator, and the hydraulic actuator. A second pipe having one end connected to the second port, one of the first pipe and the second pipe communicated with the hydraulic pump, and one of the first pipe and the second pipe; A control valve for switching between a driving state in which the other communicates with the tank, and a neutral state in which the communication between the first pipe and the second pipe with the hydraulic pump or the tank is cut off, and the pressure in the first pipe A safety valve that causes the high-pressure oil to flow into the tank when the pressure in the second pipe is equal to or higher than a set pressure; and a suction valve that draws hydraulic oil from the tank into the first pipe and the second pipe. Of the inertial body provided in the hydraulic circuit An anti-return device comprising a first electromagnetic on / off switching valve having an inlet side connected to the first pipe, a second electromagnetic on / off switching valve having an inlet side connected to the second pipe, and the first electromagnetic A third conduit connecting the outlet side of the on-off switching valve and the outlet side of the second electromagnetic on-off switching valve, a damper connected via the third conduit, and the first to third conduits The first to third pressure detecting means for detecting the pressure of the first pressure sensor and the pressure signals from the first to third pressure detecting means are taken in, and the first electromagnetic on-off switching valve and the second electromagnetic valve are taken in response to each pressure signal. A controller that outputs an open / close command to the open / close switching valve, the controller when the pressure signal from the first or second pressure detecting means rises above a set pressure value and then falls below the set pressure value An opening command is output to the first or second electromagnetic switching valve; Or when the pressure signal from the second pressure detection means becomes substantially the same as the pressure signal from the third pressure detection means, or the open state of the first or second electromagnetic switching valve exceeds a certain time. And an electric control means for outputting a close command to the first or second electromagnetic switching valve.

According to a second aspect , in the first aspect , the damper includes a cylinder main body, a piston slidably provided in the cylinder main body, and a first chamber and a second chamber defined by the piston. And a throttle hole for communicating the first chamber and the second chamber, and a spring provided in the second chamber.

Furthermore , a third invention includes, in the first invention, an operation amount detection unit that detects an operation amount of the control valve, and the controller that further takes in a signal from the operation amount detection unit. The set pressure value is calculated based on a signal from the operation amount detection means.

  According to the present invention, since the hydraulic circuit for driving the inertial body includes the on / off switching valve and the damper, the elastic energy of the pressure oil in the main pipeline is instantaneously converted to the spring energy in the damper by opening the on / off switching valve. After the opening / closing switching valve is closed, the spring energy can be gradually consumed in a state separated from the pressure oil in the main pipeline. In addition, since the capacity of the chamber in the damper is constant, even if there is an error in the opening amount of the switching valve or the control of the closing operation, a large amount of pressurized oil is not discharged from the main pipeline. As a result, it is possible to reliably prevent the inertial body from swinging back and shorten the stop distance. Further, according to the present invention, the effect is related only to the opening operation timing of the open / close switching valve, and the relationship between the opening amount and the closing operation timing is not so related. Even when the inertia of the inertia changes, the anti-swaying performance of the inertial body does not decrease.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a hydraulic circuit diagram showing a first embodiment of an inertial body swing back preventing device according to the present invention. It is a longitudinal cross-sectional view which shows the on-off switching valve which comprises 1st Embodiment of the swing back prevention apparatus of the inertial body of this invention. It is the schematic which shows the damper which comprises 1st Embodiment of the swing back prevention apparatus of the inertial body of this invention. FIG. 5 is a configuration diagram of a control / hydraulic system showing a second embodiment of the inertial body swing-back preventing device of the present invention. It is a flowchart figure which shows the control flow of 2nd Embodiment of the shake back prevention apparatus of the inertial body of this invention.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments in which an inertial body swing back preventing device of the present invention is applied to a hydraulic excavator will be described below with reference to the drawings. The present invention can be applied to all construction machines (including work machines) provided with a revolving structure, and the application of the present invention is not limited to a hydraulic excavator.

  FIG. 1 is a hydraulic circuit diagram showing a first embodiment of an inertial body swing back preventing device according to the present invention. In FIG. 1, 1 is an engine which is a power source, 2 is a main pump driven by the engine 1, 3 is a control valve for controlling the flow rate and direction of pressure oil discharged from the main pump, 4 is a swing hydraulic motor, 5 Is a swing body of a hydraulic excavator as an inertial body, 6a and 6b are first and second safety valves, 7a and 7b are first and second check valves, 8a and 8b are first and second on-off switching valves, and 9 is a throttle. Fig. 2 shows a damper with a hooked piston and a spring. The main pump 3 has, for example, a swash plate as a variable displacement mechanism. By adjusting the tilt angle of the swash plate, the capacity (displacement volume) of the main pump 3 is changed to control the discharge flow rate of the pressure oil. ing.

  In the main line 10 for supplying the pressure oil discharged from the main pump 2 to the swing hydraulic motor 4, a relief valve 11 for limiting the pressure of the pressure oil in the main line 10 and a control for controlling the direction and flow rate of the pressure oil. A valve 3 is provided. The relief valve 11 allows the pressure oil in the main line 10 to escape to the hydraulic oil tank 12 when the pressure in the hydraulic piping rises above a set pressure.

  The control valve 3 is a three-position / four-port switching control valve, and changes the opening area of the hydraulic oil flow path by switching the control valve position by the pilot pressure supplied to both pilot operating portions. Thus, the hydraulic motor 4 is driven by controlling the direction and flow rate of the hydraulic oil supplied from the main pump 2 to the hydraulic motor 4.

  The turning hydraulic motor 4 has two hydraulic oil inlets 4a and 4b, and the rotation direction can be changed by changing the supplied hydraulic oil inlet. One hydraulic oil inlet 4 a is connected to one end side of the first pipe line 13, and the other end side of the first pipe line 13 is connected to a connection port of the control valve 3. One end side of the second pipe line 14 is connected to the other hydraulic oil inlet 4 b, and the other end side of the second pipe line 14 is connected to a connection port of the control valve 3.

  The first conduit 13 is connected to the inlet side of the first safety valve 6a and the outlet side of the first check valve 7a that permits only suction. The outlet side of the first safety valve 6a and the inlet side of the first check valve 7a are connected to a conduit communicating with the tank 12, respectively. As a result, the pressure in the first pipeline 13 does not exceed the set pressure of the first safety valve 6a. Moreover, since the 1st check valve 7a sucks the hydraulic fluid in the tank 12, it prevents that the inside of the 1st pipe line 13 becomes negative pressure.

  The second conduit 14 is connected to the inlet side of the second safety valve 6b and the outlet side of the second check valve 7b that permits only suction. The outlet side of the second safety valve 6b and the inlet side of the second check valve 7b are each connected to a conduit communicating with the tank 12. As a result, the pressure in the second pipeline 14 does not exceed the set pressure of the second safety valve 6b. Further, since the second check valve 7b sucks the hydraulic oil in the tank 12, it is possible to prevent the inside of the second pipeline 14 from becoming a negative pressure.

  The first conduit 13 is connected to the inlet side of the first opening / closing switching valve 8a. Similarly, the second pipe 14 is connected to the inlet side of the second opening / closing switching valve 8b. The outlet side of the first opening / closing switching valve 8 a and the outlet side of the second opening / closing switching valve 8 b communicate with the inlet side of the damper 9 via the third conduit 15. The outlet side of the damper 9 is connected to a conduit communicating with the tank 12.

  Next, a specific structure of the first opening / closing switching valve 8a and the second opening / closing switching valve 8b will be described with reference to FIG. FIG. 2 is a longitudinal sectional view showing the first on-off switching valve 8a constituting the first embodiment of the inertial body swing-back preventing device of the present invention. In FIG. 2, the same reference numerals as those shown in FIG.

  As shown in FIG. 2, the first open / close switching valve 8a is fitted with a first spool valve body 52 and a second spool valve body 56 pressed against the valve housing 54 by the first and second springs 53 and 57 in the same direction. The first spool valve body 52 is pressed in the anti-spring direction by the pressure oil supplied from the high pressure control port 51 and is brought into contact with the rear end of the second spool valve body 56. The first spool valve body 52 has a diameter larger than the diameter of the rear end of the second spool valve body 56 that abuts the pressure oil pressure receiving portion formed in a concave shape at the rear end portion on the right side of FIG. And a contact portion 61 formed in a concave shape.

  The second spool valve body 56 includes a communication pipe 62 formed inside the shaft center, and a throttle 59 that communicates the communication pipe 62 with the outside. In addition, a hydraulic chamber 60 is formed between the second spool valve body 56 and the valve housing 54. The hydraulic chamber 60 communicates with a communication pipe 62 through a throttle 59. The rear end portion of the communication conduit 62 abuts at the contact portion 61 of the first spool valve body 52. The leading end of the communication pipe 62 communicates with the valve outlet 58. The high-pressure inlet 55 is provided in the valve housing 54, and the opening thereof is provided in the vicinity of the abutting portion between the first spool valve body 52 and the second spool valve body 56.

  When the first spool valve body 52 and the second spool valve body 56 are in contact with each other, the flow of the pressure oil in the first open / close switching valve 8a is closed by the contact portion 61. The pressure oil that is in the closed state and supplied from the high-pressure inlet 55 does not flow out. When the first spool valve body 52 and the second spool valve body 56 are separated, a gap is generated between the contact portion 61 and the rear end of the second spool valve body 56, so that the valve is opened and supplied from the high pressure inlet 55. The pressurized oil passes through the contact portion 61 and the communication pipe 62 and flows out from the valve outlet 58.

  The high pressure control port 51 and the high pressure inlet 55 are connected to the first pipeline 13 in the case of the first on / off switching valve 8a and to the second pipeline 14 in the case of the second on / off switching valve 8b. The valve outlet 58 is connected to the third pipeline 15 in both the first and second on / off switching valves 8a and 8b.

  Next, a specific structure of the damper 9 will be described with reference to FIG. FIG. 3 is a schematic view showing a damper constituting the first embodiment of the inertial body swing-back preventing device of the present invention. In FIG. 3, the same reference numerals as those shown in FIGS. 1 and 2 are the same parts, and detailed description thereof is omitted.

  As shown in FIG. 3, the damper 9 includes a cylinder body 30, an inlet 30a to which the third pipe 15 is connected, a piston 32 that can slide inside the cylinder body 30, and a piston 32 and an inlet 30a. A first chamber 32 formed inside the cylinder body 30 in between, a second chamber 33 formed inside the cylinder body 30 on the opposite side of the first chamber 32 across the piston 32, and a second chamber 33 The spring 34 is in contact with the piston 31 at one end and the innermost part of the cylinder body 30 at the other end, and an outlet 30b communicating from the second chamber 33 to the outside. The outlet 30 b is connected to a discharge pipe 16 having a throttle inside and communicating with the tank 12. The piston 32 is provided with a throttle hole 35 to enable communication of pressure oil between the first chamber 32 and the second chamber 33.

  Next, the operation of the first embodiment of the inertia body swing-back preventing apparatus of the present invention will be described. In FIG. 1, when the control valve 3 is operated to switch from the neutral position to the position (1), the pressure oil discharged from the main pump 2 passes through the first pipeline 13 from the main pipeline 10 and turns hydraulic motor. The hydraulic oil supplied to the first port 4 a and discharged from the second port 4 b of the swing hydraulic motor 4 is discharged to the tank 12 via the second conduit 14 and the control valve 3. Thereby, the turning hydraulic motor 4 rotates and the turning body 5 which is an inertial body drives.

  When the control valve 3 is returned to the neutral position from this state, the communication between the first pipeline 13 and the main pipeline 10 which is the discharge circuit of the main pump 2 is cut off, and the communication between the second pipeline 14 and the tank 12 is cut off. Is done. As a result, the supply of pressure oil to the swing hydraulic motor 4 is stopped, but the swing hydraulic motor 4 is rotated in the same direction by the inertial force of the swing body 5 to perform a pump action.

  Thereby, although the pressure in the 1st pipe line 13 falls, since the 1st check valve 7a sucks the hydraulic oil in the tank 12, it prevents that the inside of the 1st pipe line 13 becomes negative pressure. On the other hand, since the hydraulic oil is discharged from the turning hydraulic motor 4, the pressure in the second pipe 14 is increased. When this pressure becomes equal to or higher than the set pressure of the second safety valve 6b, the second safety valve 6b opens and discharges the hydraulic oil in the second pipeline 14 to the tank 12. As a result, the high-pressure hydraulic oil obtained by converting the inertial energy of the swing body 5 into elastic energy is released by the opening operation of the first safety valve 6b, so that the energy is consumed and the swing body 5 is decelerated. When the swing body 5 stops, the pressure in the second pipe line 14 also starts to decrease, and the second safety valve 6b is closed when the pressure reaches a certain value.

  Since the set value of the second safety valve 6b is, for example, about 30 MPa, even if the second safety valve 6b is closed after the opening operation, compressed hydraulic oil having elastic energy is sealed in the second pipe line 14. Yes. When this elastic energy becomes larger than the inertia energy for rotating the swing hydraulic motor 4, the swing hydraulic motor 4 starts reverse rotation. As a result, the pressure in the second pipeline 14 decreases and the pressure in the first pipeline 13 increases. A so-called swinging back of the revolving body occurs.

  In the first embodiment of the inertial body swing back prevention device of the present invention, the first and second on-off switching valves 8a and 8b and the damper 9 with a throttle are disposed to quickly end the swingback of the swinging body. Let The operation will be described below.

  The first and second on / off switching valves 8a and 8b are closed by receiving a pressure exceeding a predetermined set pressure at the pressure oil receiving portion, and then open when the pressure drops below the set pressure. Then, after a certain time elapses or when the pressure is substantially the same before and after the valve, the closing operation is performed.

  As described above, when the pressure of the second pipeline 14 is increased by the pumping action of the swing hydraulic motor 4, the pressure from the high-pressure control port 51 connected to the second pipeline 14 of the second opening / closing switching valve 8b shown in FIG. Oil flows in. When the pressure oil pressure exceeds the set pressure of the first spring 53 and the second spring 57, the front end of the first spool valve body 52 abuts with the rear end of the second spool valve body 56 and remains abutted. Move left. In the process of increasing the pressure of the pressure oil, the first spool valve body 52 and the second spool valve body 56 are kept in contact with each other, and therefore the pipe line is closed at the contact portion 61. The pressure oil supplied from 55 does not flow out.

  Next, when the second safety valve 6b operates and the pressure of the second pipe line 14 starts to decrease, the first spool valve body 52 moves to the right side as the pressure oil pressure decreases due to the action of the first spring 53. The second spool valve body 56 also tries to move to the right side by the action of the second spring 57, but since the discharge of the pressure oil remaining in the hydraulic chamber 60 is restricted by the throttle 59, the moving speed is slowed down. As a result, a difference occurs in the moving speed of the first spool valve body 52 and the second spool valve body 56, the first spool valve body 52 and the second spool valve body 56 are separated, and the contact portion 61 and the second spool valve body 56 are separated. A gap is formed between the rear end of the valve body 56. As a result, the valve is opened, and the pressure oil supplied from the high pressure inlet 55 passes through the contact portion 61 and the communication pipe 62 and flows out from the valve outlet 58 to the third pipe 15.

  The pressure oil remaining in the second pipeline 14 flows from the inlet 30a of the damper 9 into the first chamber 32 via the second opening / closing switching valve 8b and the third pipeline 15. The pressure oil that has flowed into the first chamber 32 presses the piston 31 and moves it to the back side to compress the spring 34. As a result, the elastic energy of the pressure oil in the second pipe 14 is converted into the elastic energy of the spring 34 of the damper 9.

  As a result, when the pressure in the second pipe 14 decreases and the pressure in the damper 9 increases, the pressure becomes substantially the same before and after the second opening / closing switching valve 8b. As a result, or when a certain time has elapsed, the second spool valve body 56 moves rightward while discharging the pressure oil in the hydraulic chamber 60 by the spring force of the second spring 57, and the first spool valve body 52. And the conduit is closed at the contact portion 61 of the first spool valve body 52.

  When the second opening / closing switching valve 8b is closed, the flow of the pressure oil into the damper 9 is stopped, so that the spring 34 operates in the extending direction to move the piston 31 to the first chamber 32 side. As a result, the pressure oil in the first chamber 32 moves to the second chamber 33 through the throttle hole 35 and is discharged from the outlet 30 b to the tank 12 through the discharge pipe 16. The energy of the spring 34 is consumed in the throttle hole 35 to return to the initial state.

  Even when the control valve 3 is operated to change from the position (2) to the neutral position, the same control as described above is performed.

  The present invention can instantaneously convert the elastic energy in the first or second pipes 13 and 14 into the spring energy in the damper 9 and minimize the force to return to the swing hydraulic motor 4 (swing back). Prevention). Moreover, since the flow volume discharged | emitted from the 1st or 2nd pipe lines 13 and 14 is only the volume of the damper 9, the unnecessary stop distance of the turning body 5 can be shortened.

  According to the first embodiment of the inertial body swing-back preventing device of the present invention described above, the hydraulic circuit for driving the inertial body includes the first and second on-off switching valves 8a and 8b and the damper 9. Therefore, the opening energy of the first and second on / off switching valves 8a and 8b can instantaneously convert the elastic energy of the pressure oil in the first and second pipes 13 and 14 into the spring energy in the damper 9, and the first and second After the closing operation of the two open / close switching valves 8a and 8b, the spring energy can be gradually consumed while being separated from the pressure oil in the first and second pipelines 13 and 14. Further, since the capacity of the first chamber 32 in the damper 9 is constant, even if there is an error in the control of the opening amount and the closing operation of the first and second on / off switching valves 8a and 8b, the first and second pipes A large amount of pressurized oil is not discharged from the paths 13 and 14. As a result, it is possible to reliably prevent the swinging body 5 that is an inertial body from swinging back and shorten the stop distance. Further, according to the present invention, the effect is related only to the opening operation timing of the first and second on / off switching valves 8a and 8b, and the relationship between the opening amount and the closing operation timing and other factors is weak. Even when the work posture is changed and the inertia of the revolving structure 5 is changed, the anti-swaying performance of the inertia body is not reduced.

  Further, according to the first embodiment of the swing back preventing device of the present invention described above, the outlet sides of the first and second on / off switching valves 8a and 8b and the inlet side of the throttle cylinder 9 having a damper function having a damper function. And the third pipe line 15 are connected to each other, so that problems such as oil leakage are unlikely to occur. As a result, the reliability of the hydraulic circuit to which the anti-swaying device is applied is improved.

  A second embodiment of the inertial body swing back preventing device of the present invention will be described below with reference to the drawings. FIG. 4 is a configuration diagram of a control / hydraulic system showing a second embodiment of the inertial body swing-back preventing device of the present invention, and FIG. 5 is a control flow of the second embodiment of the swing-back preventing device of the present invention. FIG. 4 and 5, the same reference numerals as those shown in FIGS. 1 to 3 are the same parts, and the detailed description thereof is omitted.

  The second embodiment of the inertial body swing back prevention device of the present invention shown in FIG. 4 is composed of a hydraulic pressure source, equipment, and the like that are substantially the same as those of the first embodiment, but the following configurations are different. .

  Instead of the first and second on / off switching valves 8a and 8b for pressure control in the first embodiment, first and second electromagnetic on / off switching valves 8c and 8d for electric control are provided. The first and second electromagnetic open / close switching valves 8 c and 8 d are provided with electromagnetic operation units 23 and 24, and open and close in response to a command signal from the controller 29. In addition, a pressure sensor 25 is provided in the first pipeline 13, a pressure sensor 26 is provided in the second pipeline 14, and a pressure sensor 27 is provided in the third pipeline 15. The pressure sensors 25, 26, and 27 detect the respective pressure sensors 25, 26, and 27. A pressure signal is input to the controller 29. The control valve 3 is provided with an operation amount signal sensor 28, and the detected operation amount signal is input to the controller 29.

  The controller 29 executes arithmetic processing to be described later based on these input signals, and outputs an opening / closing command signal to the electromagnetic operating portions 23, 24 of the first and second electromagnetic opening / closing switching valves 8c, 8d.

Next, the control of the controller 29 in the present embodiment will be described with reference to FIG.
First, the control program is started, and in step (S201), the operation amount of the control valve 3 is detected. Specifically, a control valve operation amount signal from the operation amount signal sensor 28 is taken into the controller 29.

  In step (S202), it is determined with respect to the operation amount whether or not the control valve 3 has been operated from the neutral position to the position (1) or (2). Specifically, the maximum value Ximax of the operation amount signal captured in step (S201) is calculated and stored, and it is determined whether or not the absolute value | Xi | of the operation amount Xi is greater than a predetermined value δ1. . If the manipulated variable signal | Xi | is greater than the predetermined value δ1, it is determined YES and the process proceeds to step (S203). Otherwise, the process returns to step (S202).

  In step (S203), the operation direction of the control valve 3 is determined. Specifically, it is determined whether or not the manipulated variable signal Xi captured in step (S201) is positive. If it is positive, the control valve 3 is determined to be in the position (2) and the process proceeds to step (S204). . If it is not positive, the control valve 3 is determined to be in the position (1) and the process proceeds to step (S211).

  For example, when the control valve 3 is operated to the position (2), it waits for the control valve 3 to be operated to the neutral position in step (S204). Specifically, it is determined whether or not the operation amount signal Xi of the control valve from the operation amount signal sensor 28 taken into the controller 29 is smaller than a predetermined value δ2. Here, δ2 is an operation amount signal indicating a substantially neutral position. If the manipulated variable Xi is smaller than the predetermined value δ2, YES is determined and the process proceeds to step (S205), and otherwise, the process returns to step (S204).

  In step (S205), it is determined whether or not the pressure in the first pipeline 13 exceeds the set pressure Pk. Specifically, the pressure signal of the first pipe line 13 taken in by the pressure sensor 25 is compared with the set pressure Pk, and it is determined whether or not the pressure signal is greater than the set pressure Pk. When the control valve 3 is set to the neutral position in step (S204), the communication between the second pipeline 14 and the main pipeline 10, which is the discharge circuit of the main pump 2, is blocked, and the first pipeline 13 and the tank 12 are disconnected. Communication is interrupted. As a result, the supply of the pressure oil to the swing hydraulic motor 4 is stopped, but the swing hydraulic motor 4 is rotated in the same direction by the inertial force of the swing body 5 to perform the pump action, and in the first pipeline 13. Increase the pressure oil pressure.

  Here, the set pressure Pk is determined based on the maximum value Ximax of the operation amount signal stored in step (S202). If the maximum value Ximax is large, it is assumed that the pressure of the hydraulic oil remaining in the pipe line at the time of stopping increases, so the set pressure Pk is set to a high value. On the other hand, when the operation amount is small, it is assumed that the pressure of the hydraulic oil remaining in the pipe line at the time of stoppage is low, so the set pressure Pk is set to a low value.

  In step (S205), if the pressure in the first pipeline 13 is greater than the set pressure Pk, it is determined YES and the process proceeds to step (S206). Otherwise, the process returns to step (S205).

  In step (S206), it is determined whether or not the pressure in the first pipe line 13 has decreased by Δp1 or more from the set pressure Pk. Specifically, the pressure signal of the first pipe line 13 taken in by the pressure sensor 25 is compared with the set pressure (Pk−Δp1), and it is determined whether or not the pressure signal is smaller than the set pressure (Pk−Δp1). . If the pressure in the first pipe line 13 is smaller than the set pressure (Pk−Δp1), it is determined as YES and the process proceeds to step (S207). Otherwise, the process returns to step (S206).

  In step (S207), the first electromagnetic switching valve 8c is opened. Specifically, a current signal that is an open command is output from the controller 29 to the electromagnetic operation unit 23 of the first electromagnetic switching valve 8c. As a result, the first electromagnetic on-off valve 8c is opened, and the pressure oil in the first conduit 13 flows into the first chamber 32 from the inlet 30a of the damper 9 via the third conduit 15. The pressure oil that has flowed into the first chamber 32 presses the piston 31 and moves it to the back side to compress the spring 34. As a result, the elastic energy of the pressure oil in the first pipe 13 is converted into the elastic energy of the spring 34 of the damper 9. From step (S207), the process proceeds to step (S208) and step (S209).

  In step (S208), it is determined whether or not the pressure in the first pipeline 13 and the pressure in the third pipeline 15 are substantially equal. Specifically, the difference between the pressure signal of the first pipeline 13 taken in by the pressure sensor 25 and the pressure signal of the third pipeline 15 taken in by the pressure sensor 27 is compared with the set value ΔP2, and the pressure difference signal ( It is determined whether 25-27) is smaller than the set value ΔP2. If the pressure difference signal (25-27) is smaller than the set value ΔP2, YES is determined and the process proceeds to step (S210), and otherwise, the process returns to step (S208).

  In step (S209), it is determined whether or not the opening operation time of the first electromagnetic switching valve 8c is longer than a preset time ΔT1. Specifically, the timer starts counting from the issuing of the opening command signal in step (S207), and compared with the set time ΔT1, it is determined whether or not the opening operation time of the first electromagnetic switching valve 8c is longer than the set time ΔT1. To do. If the opening operation time is longer than the set time ΔT1, YES is determined and the process proceeds to step (S210). Otherwise, the process returns to step (S209).

  In step (S210), the first electromagnetic switching valve 8c is closed. Specifically, the current signal from the controller 29 to the electromagnetic operation unit 23 of the first electromagnetic switching valve 8c is cut off. From step (S210), the process returns to the start.

  If it is determined in step (S203) that the control valve 3 is in the position (1), the process proceeds to step (S211), but the same control algorithm as in step (S204) described above is executed.

According to the second embodiment of the shake back preventing apparatus of the present invention described above, the same effects as those of the first embodiment described above can be obtained.
Further, according to the present embodiment, since the electric control is performed by the controller 29, various set pressures, the opening operation time of the on-off switching valve, and the like can be freely set. As a result, the same system can be applied to a wide range of models, and the total cost can be reduced.

DESCRIPTION OF SYMBOLS 1 Engine 2 Main pump 3 Control valve 4 Swing hydraulic motor 5 Swing body 6a 1st safety valve 6b 2nd safety valve 7a 1st check valve 7b 2nd check valve 8a 1st on-off switching valve 8b 2nd on-off switching valve 8c 1st electromagnetic on-off Switching valve 8d Second electromagnetic switching valve 9 Damper 10 Main line 12 Tank 13 First line 14 Second line 15 Third line 16 Discharge line 29 Controller 30 Cylinder body 31 Piston 32 First chamber 33 Second chamber 34 Spring

Claims (3)

A hydraulic pump, a hydraulic actuator for driving an inertial body, a first pipeline connected at one end to the first port of the hydraulic actuator, a second pipeline connected at one end to the second port of the hydraulic actuator, A driving state in which one of the first pipe and the second pipe communicates with the hydraulic pump, and the other of the first pipe and the second pipe communicates with the tank; and the first pipe And a control valve that switches between a neutral state that blocks communication with the hydraulic pump or the tank of the second pipe, and when the pressure of the first pipe and the pressure of the second pipe are equal to or higher than a set pressure, An inertia body swing back prevention device provided in a hydraulic circuit including a safety valve for allowing high-pressure oil to flow into the tank, and a suction valve for sucking hydraulic oil from the tank into the first pipe and the second pipe; There,
A first electromagnetic open / close switching valve having an inlet side connected to the first pipeline, a second electromagnetic open / close switching valve having an inlet side connected to the second pipeline, an outlet side of the first electromagnetic open / close valve, and the A third pipe connected to the outlet side of the second electromagnetic switching valve; a damper connected via the third pipe; and first to thru pressures for detecting pressures in the first through three pipes. Each pressure signal from the third pressure detecting means and the first to third pressure detecting means is taken, and an opening / closing command is output to the first electromagnetic opening / closing switching valve and the second electromagnetic opening / closing switching valve in accordance with each pressure signal. And a controller to
The controller issues an open command to the first or second electromagnetic switching valve when the pressure signal from the first or second pressure detecting means rises above a set pressure value and then falls below the set pressure value. Output,
When the pressure signal from the first or second pressure detection means becomes substantially the same as the pressure signal from the third pressure detection means, or the open state of the first or second electromagnetic opening / closing switching valve is for a certain period of time. An inertial body swing back prevention device comprising: an electric control means for outputting a close command to the first or second electromagnetic open / close switching valve when the pressure exceeds the value. In the inertial body swing-back preventing device according to claim 1 ,
The damper communicates a cylinder body, a piston slidably provided in the cylinder body, a first chamber and a second chamber defined by the piston, and the first chamber and the second chamber. A device for preventing the inertial body from swinging back, comprising a throttle hole to be moved and a spring provided in the second chamber. In the inertial body swing-back preventing device according to claim 1 ,
An operation amount detecting means for detecting an operation amount of the control valve;
The controller further taking in a signal from the operation amount detection means,
The said controller calculates the said setting pressure value based on the signal from the said operation amount detection means. The inertial body shaking prevention apparatus characterized by the above-mentioned.

Images