JP6631137B2 - hydraulic unit - Google Patents

Description

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

  Conventionally, a vane pump has an annular cam ring, a rotor disposed inside the cam ring, and a plurality of slits formed on the outer peripheral surface of the rotor, each of which is capable of moving forward and backward, and a plurality of vane pumps are in contact with the inner peripheral surface of the cam ring. And a plurality of vanes forming a compression chamber.

  In this vane pump, the vane opens by utilizing 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, and the oil flows in close contact with the inner peripheral surface of the cam ring. In a hydraulic unit that controls a vane pump by an inverter, centrifugal force is small at low rotation, and the vane does not open, so that oil may not flow. If oil is allowed to flow by increasing the rotation speed of the motor from this state, the vane opens due to centrifugal force and the oil flows when the rotation speed exceeds a certain level, causing a sudden change in the flow rate and a shock in the operation of the actuator.

  For this reason, for example, in Patent Literature 1, the vane can be reliably pressed against the inner peripheral surface even when the vane pump is rotating at a low speed by urging the vane toward the inner peripheral surface of the cam ring by a compression coil spring. A hydraulic unit is described.

JP 2005-351117 A

  However, the hydraulic unit described in Patent Literature 1 has a problem that the number of parts increases and the manufacturing cost increases because a compression coil spring is used.

  In view of the above, the present invention has been made to solve the above-described problems. By controlling the flow rate of the vane pump and opening the vane, the shock at the time of the operation of the actuator is suppressed, and the number of parts is reduced. It is an object to provide a hydraulic unit capable of suppressing costs.

A hydraulic unit according to a first invention is a hydraulic unit connected to an external device including an actuator and a shutoff valve ,
A vane pump connected to the actuator via the shut-off valve ,
Pressure detection means for detecting the pressure of oil discharged from the vane pump,
A motor driven by the inverter to drive the vane pump,
A control unit that receives a pressure command and a flow rate command, and controls the motor so as to have a pressure corresponding to the pressure command and a motor rotation speed corresponding to the flow rate command,
With
The control unit includes :
A standby state in which the shut-off valve is closed, before Ki圧 force pressure corresponding to the command is the first threshold value or less, and the flow rate in the following standby state second threshold value corresponding to prior Symbol flow amount command, the pressure when the detected pressure by the detection means does not exceed a third threshold value that can hold the state where the vanes are in the open the vane pump,
Controlling the motor so that the motor rotation speed to open the previous Kibe over emissions.

  According to the present invention, when the pressure of the oil detected by the pressure detecting means does not exceed the third threshold value in a state where the pressure command from the external device is equal to or less than the first threshold value and the flow rate command from the external device is equal to or less than the second 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 such that the vane of the vane pump opens at a motor rotational speed, the motor rotational speed increases and the vane can be opened by centrifugal force. Then, by opening the vane, the oil is ready to flow from the vane pump. By opening the vane in advance, when operating the actuator by opening the shut-off valve on the external device side, a large amount of oil suddenly flows from the vane pump when the rotation speed of the motor increases and the vane opens. Supply can be prevented, and the impact when the flow rate changes suddenly can be suppressed. By controlling the flow rate of the vane pump and opening the vane in this way, it is possible to reduce the number of parts and reduce the manufacturing cost while suppressing the shock at the time of the actuator operation due to the rapid change in the flow rate.

Hydraulic unit according to the second invention, the control unit is detected pressure by said pressure detecting means, to hold the state in which the vane is opened and becomes the third fourth higher threshold greater than the threshold value when the, the motor rotation speed the base down to open, and controls the motor so that the motor rotation speed corresponding to the pre-Symbol flow quantity command.

  According to the present invention, it is determined that the vane pump has been opened when the oil pressure detected by the pressure detecting 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, it is possible to obtain a desired flow rate of oil.

  In the first invention, in a state where the pressure command from the external device is equal to or less than the first threshold value and the flow command from the external device is equal to or less than the second threshold value, the oil pressure detected by the pressure detecting means does not exceed the third threshold value. At that time, it is determined that the oil is not flowing, that is, the vane of the vane pump is not open. At this time, by controlling the motor such that the vane of the vane pump opens at a motor rotational speed, the motor rotational speed increases and the vane can be opened by centrifugal force. Then, by opening the vane, the oil is ready to flow from the vane pump. By opening the vane in advance, when operating the actuator by opening the shut-off valve on the external device side, a large amount of oil suddenly flows from the vane pump when the rotation speed of the motor increases and the vane opens. Supply can be prevented, and the impact when the flow rate changes suddenly can be suppressed. By controlling the flow rate of the vane pump and opening the vane in this way, it is possible to reduce the number of parts and reduce the manufacturing cost while suppressing the shock at the time of the actuator operation due to the rapid change in the flow rate.

  In the second aspect, it is determined that the vane pump has been opened when the pressure of the oil detected by the pressure detecting 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, it is possible to obtain a desired flow rate of oil.

The schematic block diagram which shows the hydraulic unit which concerns on embodiment of this invention. FIG. 2 is a longitudinal sectional view of the vane pump of FIG. 1. FIG. 2 is a sectional view of an essential part taken along line III-III shown in FIG. 5 is a flowchart of control for opening 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 rotation 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 41 such as a hydraulic cylinder. The hydraulic unit 30 includes the vane pump 1, a motor 32, a pressure sensor (pressure detecting means) 33, and a unit-side control unit (control unit). 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 vane pump 1 pumps up oil from the tank 40 and discharges the oil toward the actuator 41. The suction side of the vane pump 1 is connected to a suction side flow path 35 that communicates with the tank 40, and the discharge side is connected to a discharge side flow path 36 that communicates with the actuator 41.

  As shown in FIGS. 2 and 3, the outside of the vane pump 1 is covered with a casing 2. Inside the casing 2, a rotating shaft 3 is rotatably supported by bearings 2A and 2B. A cylindrical rotor 5 is attached to the rotating shaft 3 via a key 4 so as to be able to rotate integrally with the rotating shaft 3. The outer peripheral surface of the rotor 5 is provided with a plurality of annularly arranged slits 6 (13 in the variable vane pump 1). The plurality of slits 6 penetrate the rotor 5 in the axial direction and are provided along the radial direction, and are arranged at substantially equal intervals in the circumferential direction. An annular (annular) cam ring 7 is arranged radially outside the rotor 5.

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

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

  As shown in FIG. 2, the pressing member 10 includes an elastic member 15 (a spring member in the variable vane pump 1) and a piston 16. Further, a bolt member 17 is disposed on the side of the pressing member 10 opposite to the cam ring 7. In the variable vane pump 1, by displacing the bolt member 17 along the radial direction of the rotor 5, the elastic force of the elastic member 15 acting on the cam ring 7 by the piston 16 changes, and the operation is discharged from the compression chamber 9. The discharge pressure of the fluid is adjusted. In the variable vane pump 1, the cam ring 7 is disposed at a position eccentric to the rotor 5 on the side opposite to the pressing member 10. 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 face member) and a cylindrical second side plate 22 are disposed on both end surfaces of the cam ring 7 and the rotor 5. A through hole is formed in the center of the first side plate 21 and the second side plate 22, and the rotating shaft 3 is inserted into these through holes.

  The first side plate 21 has 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 a working fluid in the compression chamber 9 for the cam ring 7. And a communication portion 31 that discharges to a radially outer space 11. The suction hole 23 is connected to a suction-side flow path 35, and the discharge hole 24 is connected to a discharge-side flow path 36.

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

  The pressure sensor 33 is provided in the discharge side flow path 36 and detects the pressure of the oil discharged from the vane pump 1. One end of the pressure sensor 33 is electrically connected in the middle of the discharge-side flow path 36, 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 as to have a motor rotation speed according 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. In addition, the unit-side control unit 34 of the present invention receives each command from the external device- side control unit 43 and, in addition to the command from the external device- side control unit 43, opens the vane 8 of the vane pump 1 by its own command. 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, a shutoff valve 46, and an actuator 41.

  The external device-side control unit 43 transmits the pressure command and the flow rate command to the unit-side control unit 34. The external device-side control unit 43 is electrically connected to the shut-off valve 46 and opens and closes the shut-off valve 46.

  The shut-off valve 46 is arranged between the vane pump 1 and the actuator 41 provided on the discharge side of the vane pump 1, and opens and closes the discharge-side flow path 36 according to a command from the external device-side control unit 43. When the shut-off valve 46 is open, the oil discharged from the vane pump 1 is supplied to the actuator 41. On the other hand, when the shut-off valve 46 is closed, the oil discharged from the vane pump 1 is prevented from being supplied to the actuator 41. Further, the shutoff valve 46 is electrically connected to the external device-side control unit 43.

  Next, 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.

  First, in step S1, the unit-side control unit 34 detects whether the pressure according to the pressure command from the external device-side control unit 43 is equal to or less than a first threshold and the flow rate according to the flow rate command is equal to or less than a second threshold. . In general, 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 enters a standby state in which no work is performed. The shut-off valve 46 is closed by a command. Since this standby state is established at the time of startup, 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 preparations for oil flow from the vane pump 1 are completed. . The first threshold is set to a small value to obtain an energy saving effect. Further, the second threshold value is set to a small value that is sufficient to replenish the amount of oil leakage of the hydraulic circuit at the time of pressure holding and does not react sensitively to a change in pressure.

  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 process proceeds to step S2. On the other hand, when the pressure corresponding to the pressure command is larger than the first threshold value, the control to open 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 has already been performed, and It is determined that the vane 8 is open, and the process proceeds to Step S6. In step S6, the unit-side controller 34 sets a flow command according to the flow QI1. Thereafter, the opening control of the vane 8 by the external device-side control unit 43 and the unit-side control unit 34 ends.

  In step S2, the unit-side control unit 34 determines whether or not the oil pressure detected by the pressure sensor 33 is equal to or less than a third threshold. As the third threshold value, a value or the like that can maintain the state in which the vane 8 is opened by using the discharge pressure even when the rotation speed decreases is set. When the oil pressure is equal to or less than the third threshold value, it is determined that the vane 8 is closed, and the process proceeds to step S3. If the oil pressure is higher than the third threshold, it is determined that the vane 8 is open, and the process proceeds to step S6, and the control ends.

  In step S3, the unit-side controller 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 such that the motor rotation speed is such that the vane 8 of the vane pump 1 opens.

  The flow rate QI2 is a value larger than the flow rate QI1, and is a theoretical flow rate calculated from the motor speed at which the vane pump 1 opens and the pump displacement. When the motor 32 is driven, the theoretical flow rate calculated from the motor rotation speed and the pump displacement of the vane pump 1 increases, as shown between time t1 and time t2 in FIG. At this time, since the vane 8 is not opened, the oil is not actually flowing. In FIG. 5A, the theoretical flow rate is indicated by a solid line L1, and the flow rate of the oil actually flowing through the vane pump 1 is indicated by a solid line L2. Further, the flow rate according to the flow rate command from the external device side control unit 43 is indicated by a dashed line. By increasing the theoretical flow rate calculated from the motor rotation speed and the pump displacement, the theoretical flow rate at which the vanes 8 open is obtained. Thereby, at time t2, the vane 8 opens and the oil actually starts flowing, 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 S4, the unit-side controller 34 determines whether or not the oil pressure detected by the pressure sensor 33 is equal to or higher than a fourth threshold (see time t3 in FIG. 5B). The fourth threshold value is set to a value that can maintain the open state of the vane 8 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. If the oil pressure is equal to or higher than the fourth threshold, it is determined that the vane 8 has been opened, and the process proceeds to step S5. If 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 S3.

  In the following step S5, the unit-side control section 34 changes the flow rate command according to the flow rate QI2 to the flow rate command according 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 at which the vane pump 1 opens. As described above, by returning the flow rate to QI1 based on the flow rate command from the external device side control unit 43 and controlling the motor 32, it is possible to obtain a desired flow rate of oil. At this time, when the oil flows and the pressure rises, a pressure is maintained and the rotation speed of the motor 32 is reduced. However, the vane 8 is opened by 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, when the rotation speed of the motor 32 is then increased as shown in FIG. 5C, it can be seen that the flow rate in the vane pump 1 increases in proportion.

[Characteristics of the hydraulic unit of the present embodiment]
The hydraulic unit 30 of the present embodiment has the following features.

  In the hydraulic unit 30 of the present embodiment, when the pressure command from the external device 45 is equal to or less than the first threshold value and the flow rate command from the external device 45 is equal to or less than the second threshold value, the oil pressure detected by the pressure sensor 33 is equal to or less than the first threshold value. If 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 motor rotation speed is such that the vane 8 of the vane pump 1 opens, the motor rotation speed increases and the vane 8 can be opened by centrifugal force. When the vane 8 is opened, the preparation for the oil to flow from the vane pump 1 is completed. By opening the vane 8 in advance, when the actuator 41 is operated by opening the shut-off valve 46 on the external device 45 side, when the rotation speed of the motor 32 increases to reach the rotation speed at which the vane 8 opens, the vane pump 1 From suddenly supplying a large amount of oil, and the impact when the flow rate changes suddenly can be suppressed. By controlling the flow rate of the vane pump 1 and opening the vane 8 in this manner, it is possible to reduce the number of parts and suppress the manufacturing cost while suppressing a shock at the time of operation of the actuator 41 due to a sudden change in the flow rate.

  In the hydraulic unit 30 of the present embodiment, it is determined that the vane pump 1 has been opened when the oil pressure detected by the pressure sensor 33 becomes 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, a desired flow rate of oil can be obtained.

  As described above, the embodiments of the present invention have been described with reference to the drawings. However, it should be considered that the specific configuration is not limited to these embodiments. The scope of the present invention is shown not only by the description of the embodiment but also by the claims, and further includes meanings equivalent to the claims and all changes within the scope.

DESCRIPTION OF SYMBOLS 1 Vane pump 30 Hydraulic unit 32 Motor 33 Pressure sensor (pressure detecting means)
34 Unit-side control unit (control unit)
45 External device

Claims (2)

In a hydraulic unit connected to an external device including an actuator and a shutoff valve ,
A vane pump connected to the actuator via the shut-off valve ,
Pressure detection means for detecting the pressure of oil discharged from the vane pump,
A motor driven by the inverter to drive the vane pump,
A control unit that receives a pressure command and a flow rate command, and controls the motor so as to have a pressure corresponding to the pressure command and a motor rotation speed corresponding to the flow rate command,
With
The control unit includes :
A standby state in which the shut-off valve is closed, before Ki圧 force pressure corresponding to the command is the first threshold value or less, and the flow rate in the following standby state second threshold value corresponding to prior Symbol flow amount command, the pressure when the detected pressure by the detection means does not exceed a third threshold value that can hold the state where the vanes are in the open the vane pump,
Hydraulic unit and controls the motor so that the motor rotation speed to open the previous Kibe over emissions. The control unit includes:
When the detected pressure by said pressure detecting means, said vane has become the fourth threshold value or more larger than the holding can and the third threshold value an open state,
Hydraulic unit according to claim 1, wherein the controller controls the motor so that the motor rotation speed the base down to open, the motor rotation speed corresponding to the pre-Symbol flow quantity command.

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