JP2017067218A - hydraulic unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic unit that can open a vane by controlling a flow rate of oil flowing in a vane pump and can suppress impact generated when the flow rate is rapidly changed.SOLUTION: A hydraulic unit includes: a first pump 25; a second pump 1 that is a vane pump; a motor 32 that drives the first pump 25 and the second pump 1 and is controlled by an inverter; a first flow passage 50 in which oil discharged from the first pump 25 flows; a second flow passage 51 in which oil discharged from the second pump flows and that is switched between a state of merging into the first flow passage 50 and a state of dividing from the first flow passage 50; a check valve 35 provided in the second flow passage 51 to prevent inflow of oil from the first flow passage 50; a third flow passage 52 that is disposed between the first pump 25 and the second pump 1 and in which the oil discharged from the first pump 25 flows in the second pump 1; and a valve train 38 for opening/closing the third flow passage 52.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a hydraulic unit having an inverter-controlled vane pump.

  Conventionally, a hydraulic unit including two gear pumps having a large capacity and a small capacity has been proposed. As such a hydraulic unit, for example, Patent Document 1 discloses a hydraulic pressure in which two large-capacity and small-capacity pumps are joined when a large flow rate is required, and a small-capacity pump is driven independently when a high pressure is necessary. The unit is listed. A large-capacity gear pump is expensive and has a limited capacity. Therefore, in order to realize a further large flow rate, it is desirable to use a vane pump that can realize a large flow rate at a low price as a large-capacity pump.

  The vane pump is disposed so as to be able to advance and retreat in an annular cam ring, a rotor disposed inside the cam ring, and a plurality of slits formed in the outer peripheral surface of the rotor, and is in contact with the inner peripheral surface of the cam ring to be in a plurality of compression chambers A plurality of vanes. In such a vane pump, the centrifugal force generated by the increase in the rotation speed of the motor and the pressure generated from the discharge port of the vane pump are used so that the vane comes into close contact with the inner peripheral surface of the cam ring and the oil flows.

JP 2002-169554 A

  However, in the hydraulic unit described in Patent Document 1, when a vane pump is used as a large-capacity pump, there is a problem that due to the characteristics of the vane pump, the vane does not open and oil does not flow from the vane pump at low pressure and low flow rate. If oil is flowed from this state by increasing the motor rotation speed, the vane is opened by centrifugal force when the rotation speed exceeds a certain level, the oil flows, the flow rate changes suddenly, and an impact occurs.

  Accordingly, the present invention has been made to solve the above-described problems, and provides a hydraulic unit that can control the flow rate of oil flowing to the vane pump to open the vane and suppress an impact that occurs when the flow rate suddenly changes. For the purpose.

The hydraulic unit according to the first invention includes a first pump and a second pump that is a vane pump;
A motor that drives the first pump and the second pump and is inverter controlled;
The first flow path through which the oil discharged from the first pump flows and the oil discharged from the second pump flow to switch between a state where the oil flows into the first flow path and a state where the oil flows from the first flow path A second flow path,
A check valve provided in the second flow path to prevent oil from flowing in from the first flow path;
A third flow path disposed between the first pump and the second pump, and the oil discharged from the first pump flows to the second pump;
A valve mechanism for opening and closing the third flow path;
Equipped with.

  In this invention, a valve mechanism is arrange | positioned between a 1st pump and a 2nd pump, and opens and closes the 3rd flow path through which oil flows from a 1st pump to a 2nd pump. When the first flow path is connected to the actuator via a shut-off valve, when the shut-off valve is closed and the third flow path is closed, oil flows from the first pump and the pressure is increased. It rises to pressure control and the flow rate cannot be increased. However, when the vane of the vane pump that is the second pump is closed, the valve mechanism opens the third flow path, so that the first pump is arranged on the suction side of the first pump via the second pump. Oil can be flowed through the tank, and the flow rate can be controlled to increase the flow rate. Therefore, by increasing the flow rate of the oil flowing into the tank via the vane pump with the vane closed and increasing the number of rotations of the motor, the motor rotation speed increases and the vane can be opened by centrifugal force. Accordingly, the vane can be opened in advance even when the shut-off valve is closed at the time of activation. And by opening a vane, oil can be poured from a vane pump. By opening the vane in advance, when opening the shut-off valve on the external device side and operating the actuator, when the rotation speed of the motor increases and the rotation speed of the vane opens, a large amount of oil suddenly flows from the vane pump. It can be prevented from being supplied and the impact when the flow rate changes suddenly can be suppressed. In this way, by controlling the flow rate of the vane pump and opening the vane, a shock during actuator operation due to a sudden change in the flow rate is suppressed.

A hydraulic unit according to a second aspect of the present invention is a pressure detection means for detecting the pressure of oil discharged from the first pump;
A control unit that receives the pressure command and the flow rate command, and controls the motor so that the pressure according to the pressure command and the motor rotation speed according to the flow rate command are obtained;
When the pressure corresponding to the pressure command from the outside is equal to or less than the first threshold and the flow rate according to the flow command from the outside is equal to or less than the second threshold, the control unit detects the pressure of the oil detected by the pressure detection means. When the third threshold is not exceeded,
The valve mechanism is opened, and the motor is controlled so that the motor rotation speed at which the vane of the vane pump is opened.

  In the present invention, when the pressure command from the external device is less than the first threshold value and the flow rate command from the external device is less than the second threshold value, the oil pressure detected by the pressure detection means does not exceed the third threshold value. It is determined that no oil is flowing, that is, the vane of the vane pump is not open. At this time, by controlling the motor so that the vane of the vane pump has a motor rotation speed that opens, the motor rotation speed increases and the vane can be opened by centrifugal force.

  The hydraulic unit according to a third aspect of the present invention is the motor rotation speed, wherein the control unit closes the valve mechanism and opens the vane pump when the oil pressure detected by the pressure detection means becomes a fourth threshold value or more. From the above, the motor is controlled so that the motor rotation speed is in accordance with the flow rate command from the outside.

  In the present invention, it is determined that the vane pump has been opened when the pressure of the oil detected by the pressure detection means becomes equal to or higher than the fourth threshold value. Thereafter, by controlling the motor so that the flow rate is based on a flow rate command from the outside, oil having a desired flow rate can be obtained.

  In the first invention, the valve mechanism is disposed between the first pump and the second pump, and opens and closes the third flow path through which oil flows from the first pump to the second pump. When the first flow path is connected to the actuator via a shut-off valve, when the shut-off valve is closed and the third flow path is closed, oil flows from the first pump and the pressure is increased. It rises to pressure control and the flow rate cannot be increased. However, when the vane of the vane pump that is the second pump is closed, the valve mechanism opens the third flow path, so that the first pump is arranged on the suction side of the first pump via the second pump. Oil can be flowed through the tank, and the flow rate can be controlled to increase the flow rate. Therefore, by increasing the flow rate of the oil flowing into the tank via the vane pump with the vane closed and increasing the number of rotations of the motor, the motor rotation speed increases and the vane can be opened by centrifugal force. Accordingly, the vane can be opened in advance even when the shut-off valve is closed at the time of activation. And by opening a vane, oil can be poured from a vane pump. By opening the vane in advance, when opening the shut-off valve on the external device side and operating the actuator, when the rotation speed of the motor increases and the rotation speed of the vane opens, a large amount of oil suddenly flows from the vane pump. It can be prevented from being supplied and the impact when the flow rate changes suddenly can be suppressed. In this way, by controlling the flow rate of the vane pump and opening the vane, a shock during actuator operation due to a sudden change in the flow rate is suppressed.

  In the second invention, the pressure of the oil detected by the pressure detection means does not exceed the third threshold value when the pressure command from the external device is equal to or lower than the first threshold value and the flow rate command from the external device is equal to or lower than the second threshold value. When the oil is not flowing, it is determined that the vane of the vane pump is not open. At this time, by controlling the motor so that the vane of the vane pump has a motor rotation speed that opens, the motor rotation speed increases and the vane can be opened by centrifugal force.

  In the third aspect of the invention, it is determined that the vane pump has been opened when the oil pressure detected by the pressure detection means has reached or exceeded the fourth threshold value. Thereafter, by controlling the motor so that the flow rate is based on a flow rate command from the outside, oil having a desired flow rate can be obtained.

1 is a schematic configuration diagram showing a hydraulic unit according to an embodiment of the present invention. The longitudinal cross-sectional view of the vane pump of FIG. Cross-sectional view of main parts along the line III-III shown in FIG. The flowchart of the control which opens a vane pump. (A) is a graph showing the relationship between time and the flow rate of the vane pump, (b) is a graph showing the relationship between time and the pressure of the vane pump, and (c) is a graph showing the relationship between the rotational speed of the motor and the flow rate.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  As shown in FIG. 1, the hydraulic unit 30 supplies the working fluid in the tank 40 to an actuator 42 such as a hydraulic cylinder. The hydraulic unit 30 includes a gear pump (first pump) 25 as a small-capacity pump, a vane pump (second pump) 1 as a large-capacity pump, a solenoid valve (valve mechanism) 38, a motor 32, a pressure sensor (pressure detection means). ) 33 and a unit-side control unit (control unit) 34. The hydraulic unit 30 joins the two pumps of the gear pump 25 and the vane pump 1 when a large flow rate is necessary, and drives the gear pump 25 alone when a high pressure is necessary. In this embodiment, oil is used as the working fluid, but it is needless to say that the present invention is not limited to this.

  The gear pump 25 is disposed in the first flow path 50 that connects the dunk 40 and the actuator 42. On the upstream side of the first flow path 50 located between the tank 40 and the gear pump 25, the oil pumped up from the tank 40 and sucked into the gear pump 25 flows. On the downstream side of the first flow path 50 located between the gear pump 25 and the actuator 42, the oil discharged from the gear pump 25 flows toward the actuator 42. Further, on the upstream side of the first flow path 50, a branch portion 55 that branches from a second flow path 51 (described later) in which the vane pump 1 is disposed is provided. On the downstream side of the first flow path 50, a merging portion 56 that merges with the second flow path 51 is provided.

  The vane pump 1 is disposed in the second flow path 51 that connects the branch portion 55 and the merging portion 56. As shown in FIGS. 2 and 3, the vane pump 1 is covered with a casing 2 on the outside. Inside the casing 2, a rotating shaft 3 is rotatably supported by a bearing 2A and a bearing 2B. A cylindrical rotor 5 is attached to the rotary shaft 3 via a key 4 so as to be rotatable integrally with the rotary shaft 3. A plurality of slits 6 (13 in this variable vane pump 1) arranged in an annular shape are provided on the outer peripheral surface of the rotor 5. The plurality of slits 6 penetrates the rotor 5 in the axial direction and is provided along the radial direction, and are arranged at substantially equal intervals in the circumferential direction. An annular (annular) cam ring 7 is disposed on the outer side in the radial direction of the rotor 5.

  In the plurality of slits 6, a plurality of vanes 8 (13 in the variable vane pump 1) disposed so as to be able to advance and retract in the radial direction in the respective slits 6 are disposed. The plurality of vanes 8 are in contact with the inner peripheral surface of the cam ring 7 by centrifugal force generated by the rotation of the rotor 5 to form a plurality of compression chambers 9. In this variable vane pump 1, 13 compression chambers 9 are formed by two adjacent vanes 8, the rotor 5, the cam ring 7, and two side plates (first side plate 21 and second side plate 22) described later. Note that the rotor 5, the cam ring 7, the vane 8, and the like are arranged in a space having a circular shape in cross section formed by the inner peripheral surface 12 of the casing 2. Moreover, the rotating shaft 3, the rotor 5, and the vane 8 rotate in the arrow direction of FIG.

  A pressing member 10 that contacts the outer peripheral surface of the cam ring 7 and presses the cam ring 7 from the radially outer side of the cam ring 7 is disposed on the outer side of the cam ring 7 in the radial direction. The pressing member 10 is disposed in a pressing member accommodating portion 13 that extends radially outward from the inner peripheral surface 12 of the casing 2. The pressing member accommodating portion 13 is formed with a discharge hole 14 for discharging the working fluid (for example, oil) in the outer space 11 to the outside.

  As shown in FIG. 2, the pressing member 10 includes an elastic member 15 (in this variable vane pump 1, a spring member) and a piston 16. A bolt member 17 is disposed on the opposite side of the pressing member 10 from the cam ring 7. In this variable vane pump 1, the bolt member 17 is displaced along the radial direction of the rotor 5, whereby the elastic force of the elastic member 15 acting on the cam ring 7 is changed by the piston 16, and the operation is discharged from the compression chamber 9. The fluid discharge pressure is adjusted. In this variable vane pump 1, the cam ring 7 is arranged at a position eccentric to the opposite side of the pressing member 10 with respect to the rotor 5. That is, the center position of the cam ring 7 is on the opposite side of the pressing member 10 with respect to the center position of the rotor 5. At this time, the outer peripheral surface of the cam ring 7 opposite to the pressing member 10 is in contact with the inner peripheral surface 12 of the casing 2.

  As shown in FIG. 3, a cylindrical first side plate 21 (end surface member) and a cylindrical second side plate 22 are disposed on both end faces of the cam ring 7 and the rotor 5. Through holes are formed in the center of the first side plate 21 and the second side plate 22, and the rotary shaft 3 is inserted through these through holes.

  The first side plate 21 includes a suction hole 23 for supplying a working fluid (for example, oil) to the compression chamber 9, a discharge hole 24 for discharging the working fluid in the compression chamber 9, and the working fluid in the compression chamber 9 for the cam ring 7. It has the communication part 31 discharged | emitted to the outer side space 11 of radial direction outer side. The suction hole 23 is connected to the first flow path 50, and the discharge hole 24 is connected to the second flow path 51.

  As shown in FIG. 1, oil that is branched from the branch portion 55 and sucked into the vane pump 1 flows on the upstream side of the second flow path 51 located between the branch portion 55 and the vane pump 1. A switching unit 57 is provided on the downstream side of the second flow path 51 located between the vane pump 1 and the merging unit 56. The switching unit 57 switches between a state where the oil discharged from the vane pump 1 joins the first flow path 50 and a state where the oil flows from the first flow path 50.

  A check valve 35 that prevents oil from flowing from the first flow path 50 into the second flow path 51 is provided in the second flow path 51 between the switching section 57 and the merging section 56. In a state where the oil in the second flow path 51 merges with the first flow path 50, the oil discharged from the vane pump 1 flows toward the merge section 56 via the switching section 57 and the check valve 35.

  A pilot check valve 36 is provided in the flow path on the opposite side of the merging portion 56 of the switching portion 57. A second electromagnetic valve 39 that is switched by a signal from the external device side control unit 43 is provided downstream of the pilot check valve 36. By switching the second electromagnetic valve 39 and causing the flow rate of the merging portion 56 to flow through the pilot check valve 36, pilot pressure is applied to open the pilot check valve 36, and oil in the second flow path 51 is piloted from the switching portion 57. It flows through the check valve 36 to the reservoir 37. As a result, the oil flowing to the merging portion 56 is only the oil flowing from the gear pump 25. When the second electromagnetic valve 39 is switched so that the flow rate of the merging portion 56 does not flow to the pilot check valve 36, the pilot check valve 36 is closed and the oil in the second flow path 51 flows from the switching portion 57 to the check valve 35. It flows to the junction 56 through. The check valve 35 and the pilot check valve 36 constitute a pump capacity selection block 61.

  The first electromagnetic valve 38 is disposed in the middle of the third flow path 52 and opens and closes the third flow path 52. The third flow path 52 is disposed between the gear pump 25 and the vane pump 1, and causes the oil discharged from the gear pump 25 to flow to the vane pump 1. Specifically, the third flow path 52 connects the solenoid valve inlet 58 and the solenoid valve outlet 59. The solenoid valve inlet 58 is disposed downstream of the gear pump 25 in the first flow path 50, that is, between the gear pump 25 and the merging section 56. The solenoid valve outlet 59 is a vane pump in the second flow path 51. 1 on the downstream side, that is, between the vane pump 1 and the switching unit 57. The first electromagnetic valve 38 is electrically connected to the unit side control unit 34.

  The motor 32 is inverter-controlled by a command from the external device side control unit 43 or the unit side control unit 34 and drives the gear pump 25 and the vane pump 1. The motor 32 is connected to the gear pump 25 and the vane pump 1, and is electrically connected to the unit side control unit 34.

  The pressure sensor 33 is provided between the vane pump 1 and the solenoid valve inlet 58 of the first flow path 50 and detects the pressure of the oil discharged from the gear pump 25. When the pump capacity selection block 61 switches to the merge or when the first electromagnetic valve 38 is open, the pressure sensor 33 detects the discharge pressure of the gear pump 25 and the discharge pressure of the vane pump 1. One end of the pressure sensor 33 is electrically connected in the middle of the first flow path 50, and the other end is electrically connected to the unit-side control unit 34.

  The unit-side control unit 34 receives a pressure command and a flow rate command from an external device side control unit 43, which will be described later, and controls the motor 32 so that the motor rotation speed corresponds to the pressure and flow rate command according to the pressure command. The unit side control unit 34 is electrically connected to the external device side control unit 43 and receives a pressure command and a flow rate command from the external device side control unit 43. The unit side control unit 34 drives the motor 32 based on each command from the external device side control unit 43. The unit-side control unit 34 of the present invention receives each command from the external device-side control unit 43 and has its own command separately from the command from the external control-side control unit 43 to open the vane 8 of the vane pump 1. Is used to drive the motor 32.

  The external device 45 connected to the hydraulic unit 30 includes an external device side control unit 43, an actuator 42, and a cutoff valve 46. The external device side control unit 43 transmits a pressure command and a flow rate command to the unit side control unit 34. The external device side control unit 43 is electrically connected to the shutoff valve 46 and opens and closes the shutoff valve 46.

  The shut-off valve 46 is disposed between the hydraulic unit 30 and an actuator 42 provided on the discharge side of the hydraulic unit 30, and opens and closes the first flow path 50 according to a command from the external device side control unit 43. In the state where the shut-off valve 46 is opened, the oil discharged from the hydraulic unit 30 is supplied to the actuator 42. On the other hand, when the shutoff valve 46 is closed, the oil discharged from the hydraulic unit 30 is prevented from being supplied to the actuator 42. The shutoff valve 46 is electrically connected to the external device side control unit 43.

  Next, the control for opening the vane 8 of the vane pump 1 by the external device side control unit 43 and the unit side control unit 34 will be described in detail with reference to FIG. The external device side control unit 43 transmits a flow rate command corresponding to the flow rate QI1 to the unit side control unit 34. In the initial state, the first electromagnetic valve 38 is closed.

  First, in step S1, the unit side control unit 34 detects whether or not the pressure according to the pressure command from the external device side control unit 43 is equal to or less than the first threshold value and the flow rate according to the flow rate command is equal to or less than the second threshold value. . Further, when the pressure according to the pressure command is equal to or less than the first threshold value and the flow rate according to the flow rate command is equal to or less than the second threshold value, the hydraulic unit 30 side enters a standby state where no work is performed, and the command from the external device side control unit 43 To close the shut-off valve 46. Since this standby state is established at the time of start-up, the control for opening the vane 8 of the vane pump 1 by the external device side control unit 43 and the unit side control unit 34 is performed in this standby state, so that the oil is ready to flow from the vane pump 1. . The first threshold value is set to a small value in order to obtain an energy saving effect. The second threshold value is set to a small value that is sufficient to replenish the amount of oil leakage in the hydraulic circuit at the time of holding pressure, and that does not react sensitively to changes in pressure.

  When the pressure according to the pressure command is equal to or lower than the first threshold value and the flow rate according to the flow rate command is equal to or lower than the second threshold value, it is determined that the vane 8 of the vane pump 1 is not open, and the process proceeds to step S2. On the other hand, when the pressure according to the pressure command is larger than the first threshold value, the control of opening the vane 8 of the vane pump 1 by the external device side control unit 43 and the unit side control unit 34 in the standby state is already performed, and the vane 8 is It judges that it is open, and proceeds to step S6.

  In step S <b> 2, the unit side control unit 34 opens the first electromagnetic valve 38. By opening the first electromagnetic valve 38, the third flow path 52 is opened, and the oil pumped up by the gear pump 25 flows from the electromagnetic valve inlet 58 into the third flow path 52 and the first electromagnetic valve 38. Thereby, the flow volume of the oil which flows into the vane pump 1 in which the vane 8 is closed is increased, and the vane 8 can be easily opened by increasing the number of rotations of the motor 32. The oil discharged from the first electromagnetic valve 38 passes through the vane pump 1 via the electromagnetic valve outlet 59 and is returned to the tank 40 from the branching portion 55. In this way, when the first electromagnetic valve 38 opens the third flow path 52, oil can flow from the gear pump 25 to the tank 40 via the vane pump 1, and the flow rate can be increased by increasing the flow rate. it can. Therefore, the vane 8 can be opened by increasing the flow rate of the oil flowing into the tank 40 via the vane pump 1 in which the vane 8 is closed and increasing the rotation speed of the motor 32.

  When oil flows from the solenoid valve outlet 59 to the branching portion 55 through the vane pump 1, the working fluid is supplied to the compression chamber 9 through the discharge hole 24 in the vane pump 1, and the inside of the compression chamber 9 is supplied from the suction hole 23. Discharge the working fluid.

  In step S3, the unit side control unit 34 determines whether or not the pressure of the oil discharged from the vane pump 1 is equal to or less than a third threshold value. The third threshold is set to a value that can maintain the state in which the vane 8 is opened using the discharge pressure even when the rotational speed decreases. When the first electromagnetic valve 38 is open, the pressure sensor 33 detects the discharge pressure of the gear pump 25 and the discharge pressure of the vane pump 1. When the pressure of the oil discharged from the vane pump 1 is equal to or lower than the third threshold value, it is determined that the vane 8 is closed, and the process proceeds to step S4. When the oil pressure is greater than the third threshold, it is determined that the vane 8 is open, and the process proceeds to step S6.

  In step S4, the unit side control unit 34 sets the flow rate command according to the flow rate QI2, so that the motor 32 is driven so that the flow rate of the vane pump 1 becomes QI2. At this time, the motor 32 is controlled so as to have a motor rotation speed at which the vane 8 of the vane pump 1 is opened.

  The flow rate QI2 is a value larger than the flow rate QI1, and is a theoretical flow rate calculated from the motor rotation speed at which the vane pump 1 opens and the pump capacity. As a result, as shown between time t1 and time t2 in FIG. 5A, the theoretical flow rate calculated from the motor rotational speed of the vane pump 1 and the pump capacity increases. At this time, since the vane 8 is not open, no oil actually flows. In FIG. 5A, the theoretical flow rate is indicated by a solid line L1, and the flow rate of oil actually flowing to the vane pump 1 is indicated by a solid line L2. Further, the flow rate corresponding to the flow rate command from the external device side control unit 43 is indicated by a one-dot chain line. By increasing the theoretical flow rate calculated from the motor rotation speed and the pump capacity, the theoretical flow rate at which the vane 8 opens is obtained. As a result, the vane 8 is opened at time t2 and oil actually starts to flow, and the pressure of the vane pump 1 also increases (see FIG. 5B). In FIG. 5B, the oil pressure detected by the pressure sensor 33 is indicated by a solid line.

  Next, in step S5, the unit side controller 34 determines whether or not the pressure of the oil discharged from the vane pump 1 is equal to or higher than a fourth threshold value (see time t3 in FIG. 5B). The fourth threshold value is set to a value that can keep the vane 8 open using the discharge pressure even when the rotation speed of the motor 32 decreases, or a value that is slightly larger than the third threshold value to provide hysteresis. Is done. When the oil pressure is equal to or greater than the fourth threshold, it is determined that the vane 8 has been opened, and the process proceeds to step S6. When the oil pressure is less than the fourth threshold, it is determined that the vane 8 is still closed, and the process returns to step S4.

  In step S <b> 6, the unit side control unit 34 closes the first electromagnetic valve 38. As a result, the oil discharged from the gear pump 25 flows through the first flow path 50 toward the joining portion 56. Further, the oil discharged from the vane pump 1 flows through the second flow path 51 toward the switching unit 57. At this time, the vane pump 1 rotates in the direction of the arrow in FIG.

  In subsequent step S7, the unit-side control unit 34 changes the flow rate command corresponding to the flow rate QI2 to the flow rate command corresponding to the flow rate QI1 (see time t3 in FIG. 5A). That is, the unit-side control unit 34 controls the motor 32 so that the motor rotation speed according to the flow rate command from the external device-side control unit 43 is changed from the motor rotation speed opened by the vane pump 1. In this way, by switching the pump capacity by the pump capacity selection block 61, the first solenoid valve 38 is closed and the motor 32 is controlled by returning to the flow rate QI1 based on the flow rate command from the external device side control unit 43. An oil having a desired flow rate can be obtained. At this time, when oil flows and the pressure increases, the pressure is maintained and the rotation speed of the motor 32 decreases, but the vane 8 opens using the discharge pressure, and the oil flows in close contact with the inner peripheral surface of the cam ring 7. Hold. Then, the opening control of the vane 8 ends.

  By performing the opening control of the vane pump 1 of the present invention and then increasing the rotational speed of the motor 32 as shown in FIG. 5C, the flow rate of oil obtained from the gear pump 25 and the vane pump 1 is proportional. It can be seen that it increases.

[Features of hydraulic unit of this embodiment]
The hydraulic unit 30 of this embodiment has the following characteristics.

  In the hydraulic unit 30 of the present embodiment, the first electromagnetic valve 38 is disposed between the gear pump 25 and the vane pump 1, and opens and closes the third flow path 52 through which oil flows from the gear pump 25 to the vane pump 1. When the shutoff valve 46 is closed and the third flow path 52 is closed, oil flows from the gear pump 25 to increase the pressure, and pressure control is performed, and the flow rate cannot be increased. However, when the vane 8 of the vane pump 1 is closed, the first solenoid valve 38 opens the third flow path 52 so that oil can flow from the gear pump 25 to the tank 40 via the vane pump 1. Control can increase the flow rate. Therefore, the vane 8 can be opened by increasing the flow rate of the oil flowing into the tank 40 via the vane pump 1 in which the vane 8 is closed and increasing the rotation speed of the motor 32. Accordingly, the vane 8 can be opened in advance even when the shut-off valve 46 is closed at the time of activation. When the shutoff valve 46 is opened and the actuator 42 is operated, a large amount of oil is prevented from being suddenly supplied from the vane pump 1 when the rotational speed of the motor 32 increases to reach the rotational speed at which the vane 8 opens. The impact when the flow rate changes suddenly can be suppressed. Further, since the pressure sensor 33 is provided on the gear pump 25 side, the discharge pressure from the vane pump 1 can be detected by the pressure sensor 33, and a new pressure detecting means for detecting the discharge pressure from the vane pump 1 is not necessary, thereby reducing the cost. I can plan.

  In the hydraulic unit 30 of the present embodiment, the pressure of the oil detected by the pressure sensor 33 is the first when the pressure command from the external device 45 is equal to or lower than the first threshold value and the flow rate command from the external device 45 is equal to or lower than the second threshold value. When the threshold value is not exceeded, it is determined that oil is not flowing, that is, the vane 8 of the vane pump 1 is not open. At this time, by controlling the motor 32 so that the vane 8 of the vane pump 1 is opened, the motor rotation speed is increased and the vane 8 can be opened by centrifugal force. Then, by opening the vane 8, the oil is ready to flow from the vane pump 1. By opening the vane 8 in advance, when the shutoff valve 46 on the external device 45 side is opened and the actuator 42 is operated, the vane pump 1 is operated when the rotation speed of the motor 32 increases and the vane 8 opens. Therefore, it is possible to prevent a large amount of oil from being supplied suddenly and to suppress an impact when the flow rate changes suddenly. In this way, by controlling the flow rate of the vane pump and opening the vane, a shock during operation of the actuator 42 due to a sudden change in the flow rate is suppressed.

  In the hydraulic unit 30 according to the present embodiment, it is determined that the vane pump 1 has been opened when the oil pressure detected by the pressure sensor 33 is equal to or higher than the fourth threshold value. Thereafter, by controlling the motor 32 so that the flow rate is based on the flow rate command from the external device 45, oil with a desired flow rate can be obtained. Further, by closing the first electromagnetic valve 38, the pump capacity switching by the pump capacity selection block 61 becomes effective.

  As mentioned above, although embodiment of this invention was described based on drawing, it should be thought that a specific structure is not limited to these embodiment. The scope of the present invention is shown not only by the above description of the embodiments but also by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

  Although the pressure sensor 33 is provided in the first flow path 50 in the embodiment, the present invention is not limited to this. The discharge pressure of the vane pump 1 may be directly detected by providing the pressure sensor 33 on the downstream side of the vane pump 1 in the second flow path 51.

1 Vane pump (second pump)
25 Gear pump (first pump)
30 Hydraulic unit 32 Motor 33 Pressure sensor (pressure detection means)
34 Unit side control unit (control unit)
35 Check valve 38 First solenoid valve (valve mechanism)
50 1st flow path 51 2nd flow path 52 3rd flow path

Claims (3)

A first pump and a second pump that is a vane pump;
A motor that drives the first pump and the second pump and is inverter controlled;
The first flow path through which the oil discharged from the first pump flows and the oil discharged from the second pump flow to switch between a state where the oil flows into the first flow path and a state where the oil flows from the first flow path A second flow path,
A check valve provided in the second flow path to prevent oil from flowing in from the first flow path;
A third flow path disposed between the first pump and the second pump, and the oil discharged from the first pump flows to the second pump;
A valve mechanism for opening and closing the third flow path;
A hydraulic unit comprising: Pressure detecting means for detecting the pressure of the oil discharged from the first pump;
A control unit that receives the pressure command and the flow rate command, and controls the motor so that the pressure according to the pressure command and the motor rotation speed according to the flow rate command are obtained;
When the pressure corresponding to the pressure command from the outside is equal to or less than the first threshold and the flow rate according to the flow command from the outside is equal to or less than the second threshold, the control unit detects the pressure of the oil detected by the pressure detection means. When the third threshold is not exceeded,
2. The hydraulic unit according to claim 1, wherein the valve mechanism is opened and the motor is controlled so that a motor rotation speed at which the vane of the vane pump is opened is achieved.   The controller closes the valve mechanism when the oil pressure detected by the pressure detection means becomes a fourth threshold value or more, and responds to an external flow command from a motor rotation speed at which the vane pump opens. The hydraulic unit according to claim 2, wherein the motor is controlled to have a motor rotation speed.

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