WO2019054512A1

WO2019054512A1 - Hydraulic pump

Info

Publication number: WO2019054512A1
Application number: PCT/JP2018/034307
Authority: WO
Inventors: 藤井規臣; 西谷拓也; 中井雅也
Original assignee: アイシン・エィ・ダブリュ株式会社
Priority date: 2017-09-15
Filing date: 2018-09-14
Publication date: 2019-03-21
Also published as: WO2019054511A1; WO2019054510A1

Abstract

A pump unit (3) comprises a cylinder (30) and a piston (40) that reciprocally moves along an axial direction (DL). An actuator (2) comprises a cylindrical coil body (10) and a movable body (20) that is capable of reciprocally moving in the axial direction (DL) relative to the cylindrical coil body (10). Impelling members (71, 72) for resonance are provided that impel the piston (40) or the movable body (20) in the axial direction (DL). A control unit controls the actuator (2) such that the movable body (20) reciprocally moves along the axial direction (DL) at a set drive frequency. The control unit: determines a corrected resonance frequency obtained by correcting, according to oil impact, a resonance frequency of a vibrating system including the piston (40), the movable body (20), and the impelling members (71, 72) for resonance; and controls the actuator (2) such that the movable body (20) reciprocally moves along the axial direction (DL) at the corrected resonance frequency.

Description

Hydraulic pump

The present invention relates to a hydraulic pump including an actuator, a pump unit that is driven by the actuator to generate hydraulic pressure, and a control unit that controls the driving of the pump unit by the actuator.

As an actuator for driving a movable body along the axial direction, Japanese Patent Laid-Open No. 2004-140902 (Patent Document 1) discloses a linear motor that efficiently reciprocates the movable body by utilizing a resonance phenomenon. Hereinafter, reference numerals in parentheses in the description of the background art are those of Patent Document 1. FIG. 8 of Patent Document 1 describes a linear compressor that sequentially compresses the refrigerant gas drawn into the compression chamber (38) by reciprocating movement of the piston (36) and discharging it to an external refrigeration cycle. And the linear motor (37) which drives this linear compressor is comprised so that the mover (21) connected with the piston (36) may be resonated using a coil spring (30a, 30b). Specifically, in paragraph 0106 of Patent Document 1, the frequency of the power source for energizing the linear motor (37), the mass of the mover (21) and the stator (22), and the spring constant of the coil spring (30a, 30b) It is described that the mover (21) is efficiently reciprocated by matching the resonance frequency obtained from the above.

By the way, as in the technique described in Patent Document 1, when the efficiency of the actuator is increased (in other words, the reduction of energy consumption is achieved) by matching the drive frequency of the actuator with the resonant frequency of the vibration system, Accordingly, if the resonance frequency changes and the deviation from the drive frequency of the actuator increases, the efficiency of the actuator decreases. However, in Patent Document 1, it is not assumed that the resonance frequency of the vibration system changes according to the operating state. According to the study of the present inventors, it has been found that when the pump unit of the hydraulic pump is driven by the actuator, the resonance frequency of the vibration system is likely to change due to the influence of oil.

JP 2004-140902 A

Therefore, there is a need for a hydraulic pump that can maintain high efficiency of the actuator even when the resonance frequency of the vibration system changes.

A hydraulic pump according to the present disclosure is a hydraulic pump including an actuator, a pump unit driven by the actuator to generate hydraulic pressure, and a control unit controlling drive of the pump unit by the actuator, The pump portion is disposed in a cylinder having a suction port and a discharge port, and a pressure chamber formed inside the cylinder so as to communicate with the suction port and the discharge port, and reciprocates along the axial direction of the cylinder A moving piston, and the actuator is a cylindrical coil body arranged coaxially with the cylinder in the axial direction, and is connected to the piston and viewed in the radial direction of the cylinder. A movable body disposed so as to overlap with the cylindrical coil body, and movable reciprocally in the axial direction with respect to the cylindrical coil body; The movable body is driven toward at least one side in the axial direction by magnetic flux generated from the cylindrical coil body, and provided with a resonance biasing member that biases the piston or the movable body in the axial direction. The control unit controls the actuator such that the movable body reciprocates along the axial direction at a set drive frequency, and the control unit controls the piston, the movable body, and the urging for resonance. The resonance frequency of the vibration system including the member is corrected according to the influence of oil, and a correction resonance frequency is determined, and the actuator is controlled so that the movable body reciprocates along the axial direction at the correction resonance frequency. .

According to this configuration, the piston can be reciprocated along the axial direction by utilizing the resonance phenomenon of the piston by the resonance biasing member. That is, the thrust generated by the actuator can be compensated by the resonance phenomenon. Thereby, it is possible to reduce the energy consumption of the actuator for generating the thrust required of the piston. That is, the efficiency of the actuator can be improved by utilizing the resonance phenomenon of the piston.
By the way, the inventors of the present invention, as a result of research, when the pump unit is driven by the actuator, since the fluid medium is oil, the piston and the biasing member for resonance are compared with the case where the fluid medium is gas. It has been found that the resonance frequency of the vibration system including and is easily changed by the influence of oil. Such a change in resonance frequency is caused by the fact that when the oil compressed and expanded inside the pressure chamber is regarded as a spring, the spring constant of the oil changes in accordance with the operating state of the pump section. . Based on such knowledge, in the above configuration, when the control unit controls the actuator such that the movable body reciprocates along the axial direction at the set drive frequency, the piston, the movable body, and the one for resonance The resonant frequency of the vibration system including the biasing member is corrected according to the influence of oil, and a corrected resonant frequency is determined, and the actuator is controlled so that the movable body reciprocates along the axial direction at the corrected resonant frequency. Thereby, when the resonance frequency of the vibration system changes due to the influence of oil, it becomes possible to drive the actuator at the corrected resonance frequency which is the resonance frequency after the change.
Therefore, according to the above configuration, even when the resonance frequency of the vibration system changes, the efficiency of the actuator can be maintained high.

Further features and advantages of the hydraulic pump will become clear from the following description of the embodiments described with reference to the drawings.

Sectional view of hydraulic pump with piston in center of range of motion Cross section of hydraulic pump with piston at one end of range of motion Sectional view of hydraulic pump with piston at other end of range of motion Characteristic chart showing the relationship between angular frequency ratio and amplitude ratio Schematic diagram of the case Diagram showing oil temperature dependence of resonant angular frequency A schematic diagram of a map that defines the relationship between oil temperature and drive angular frequency A schematic diagram of a map that defines the relationship between discharge pressure and drive angular frequency Diagram showing an example of a drive circuit Diagram showing a drive circuit according to a comparative example

Embodiments of a hydraulic pump will be described with reference to the drawings. In the present embodiment, each of the first biasing member 71 and the second biasing member 72 corresponds to a “resonance biasing member”.

As shown in FIG. 1, the hydraulic pump 1 includes an actuator 2 and a pump unit 3 driven by the actuator 2 to generate an oil pressure. Further, as shown in FIG. 5, the hydraulic pump 1 includes a control unit 90 that controls the drive of the pump unit 3 by the actuator 2. As described below, the pump unit 3 is a piston pump that pumps oil by reciprocating the piston 40 along the axial direction DL (axial direction of the cylinder 30), and the actuator 2 is connected to the piston 40 A thrust for moving the movable body 20 along the axial direction DL is generated. That is, the actuator 2 is a linear actuator. The actuator 2 is an electromagnetic actuator that generates a thrust of the movable body 20 by an electromagnetic force.

As shown in FIG. 1, the pump unit 3 includes a cylinder 30 having an inlet 31 and an outlet 32 and a piston 40 that reciprocates along the axial direction DL. A pressure chamber 33 is formed in the cylinder 30 so as to communicate with the suction port 31 and the discharge port 32, and the piston 40 is disposed in the pressure chamber 33. Then, as the piston 40 reciprocates along the axial direction DL, the oil 83 (see FIG. 5) sucked into the pressure chamber 33 from the suction port 31 is discharged from the discharge port 32 to the outside of the pressure chamber 33. . In the present embodiment, as shown in FIG. 5, a suction oil passage 85 is connected to the suction port 31 and a discharge oil passage 86 is connected to the discharge port 32 (see also FIG. 1). Although the details will be described later, the suction port 31 is disposed so as to suction the oil 83 stored in the oil storage portion 82.

As shown in FIG. 1, the cylinder 30 includes a cylindrical portion 34 formed in a cylindrical shape (here, cylindrical shape) extending in the axial direction DL, and the pressure chamber 33 has an inner periphery of the cylindrical portion 34. It is formed surrounded by a surface (inner wall). In the present embodiment, the suction port 31 is formed at the opening of one side of the cylindrical portion 34 in the axial direction DL (the first side DL1 in the axial direction described later), and the discharge port 32 is a peripheral wall portion of the cylindrical portion 34 Is formed to penetrate in the radial direction DR (the radial direction of the cylinder 30). That is, the discharge port 32 is provided to communicate the inner peripheral surface and the outer peripheral surface of the cylinder 30 (specifically, the cylindrical portion 34). Hereinafter, the side on which the cylinder 30 is disposed with respect to the actuator 2 in the axial direction DL (specifically, the tubular coil body 10 described later) is referred to as an axial first side DL1, and the axial direction first in the axial direction DL The side opposite to the side DL1 is referred to as an axial second side DL2.

The piston 40 includes a pressure chamber 33 (pump chamber), a first pressure chamber 33a (first pump chamber) on the first axial side DL1, and a second pressure chamber 33b (second pump chamber) on the second axial side DL2. In the two chambers, and are arranged in the axial direction DL. The first pressure chamber 33 a is formed in communication with the suction port 31, and the second pressure chamber 33 b is formed in communication with the discharge port 32. That is, the discharge port 32 communicates with the second pressure chamber 33 b. Hereinafter, a portion which divides the first pressure chamber 33a and the second pressure chamber 33b in the piston 40 is referred to as a main body portion 41. In order to partition the first pressure chamber 33a and the second pressure chamber 33b in an oil-tight manner, the space between the outer peripheral surface of the main body 41 and the inner peripheral surface of the cylinder 30 (specifically, the cylindrical portion 34) is A second seal member S2 (annular seal member) that seals is provided on the outer peripheral surface of the main body portion 41. Here, the first pressure chamber 33a and the second pressure chamber 33b are partitioned in an oil-tight manner in a state where a second check valve V2 described later is closed.

The portion of the pressure chamber 33 (specifically, the second pressure chamber 33b) of the cylinder 30 which forms the wall of the second side DL2 in the axial direction (the portion which forms the first wall 61 described later) A first through hole 61a penetrating in the direction DL is formed, and the piston 40 has a first portion 51 arranged to penetrate the first through hole 61a. The first portion 51 and the main body portion 41 are both formed to have a cylindrical (here, cylindrical) outer peripheral surface extending in the axial direction DL, and the outer peripheral surface of the first portion 51 is the outer peripheral surface of the main body 41 It has a smaller diameter than that. Therefore, as shown in FIGS. 1 to 3, the volume of the second pressure chamber 33b increases as the piston 40 moves to the first axial side DL1, and decreases as the piston 40 moves to the second axial side DL2. Become. On the other hand, the volume of the first pressure chamber 33a decreases as the piston 40 moves to the first axial side DL1, and increases as the piston 40 moves to the second axial side DL2. Thus, the piston 40 includes the main body 41 and the first portion 51. And as above-mentioned, the main-body part 41 divides the pressure chamber 33 into the 1st pressure chamber 33a and the 2nd pressure chamber 33b adjacent to axial direction 2nd side DL2 with respect to the 1st pressure chamber 33a. The first portion 51 defines the second pressure chamber 33 b and an intermediate chamber 60 described later.

In the flow path of the oil 83 directed to the

suction port

31 or 31, the flow of the oil 83 directed to the first pressure chamber 33 a (that is, the flow of the oil 83 directed to the downstream side) is permitted. A first check valve V1 is provided to restrict the flow of the oil 83 (that is, the flow of the oil 83 toward the upstream side). As shown in FIG. 1, in the present embodiment, the first check valve V1 is provided at the suction port 31. Here, the first check valve V1 includes a spherical valve body and a biasing member that biases the valve body in the valve closing direction. The first check valve V1 has a predetermined hydraulic pressure (the above-described urging) than the hydraulic pressure on the upstream side (here, the hydraulic pressure of the suction oil passage 85) is lower than the hydraulic pressure on the downstream side (here, the hydraulic pressure of the first pressure chamber 33a). It is configured to open when the oil pressure corresponding to the biasing force of the member is higher than the above) and to close the valve otherwise.

Further, in the flow path of the oil 83 between the first pressure chamber 33a and the second pressure chamber 33b, the flow of the oil 83 toward the second pressure chamber 33b (that is, the flow of the oil 83 toward the downstream side) is allowed. And a second check valve V2 for restricting the flow of the oil 83 directed to the opposite side (that is, the flow of the oil 83 directed to the upstream side). In the present embodiment, the flow path of the oil 83 between the first pressure chamber 33a and the second pressure chamber 33b is formed by a hole that penetrates the piston 40 (specifically, the main body 41) in the axial direction DL. The second check valve V2 is provided integrally with the piston 40 (specifically, the main body 41). That is, the second check valve V2 is built in the piston 40. Here, the second check valve V2 includes a spherical valve body and a biasing member that biases the valve body in the valve closing direction. The second check valve V2 has a predetermined hydraulic pressure (above: the hydraulic pressure of the first pressure chamber 33a here) than the hydraulic pressure of the downstream side (here, the hydraulic pressure of the second pressure chamber 33b). It is configured to open when the oil pressure is higher than the hydraulic pressure corresponding to the biasing force of the biasing member, and to close the valve otherwise. In addition, although the 1st non-return valve V1 and the 2nd non-return valve V2 are made into a valve which has a spherical valve body here, as a 1st non-return valve V1 or the 2nd non-return valve V2, a poppet valve etc. Other construction valves may be used.

Since the pump unit 3 is configured as described above, when the piston 40 moves to the second axial side DL2 in the axial direction as shown in FIG. 3, the volume of the first pressure chamber 33a increases, so that the hydraulic pressure of the first pressure chamber 33a is increased. As the volume of the second pressure chamber 33b decreases, the hydraulic pressure of the second pressure chamber 33b rises. Along with this, the first check valve V1 is opened and the second check valve V2 is closed, and the oil 83 of the suction oil passage 85 flows into the first pressure chamber 33a from the suction port 31, and The oil 83 in the pressure chamber 33b is discharged from the discharge port 32 to the discharge oil passage 86 (see also FIG. 5). Further, as shown in FIG. 2, when the piston 40 moves to the first axial side DL1 in the axial direction, the volume of the first pressure chamber 33a decreases, so that the hydraulic pressure of the first pressure chamber 33a rises and the second pressure chamber 33b The hydraulic pressure of the second pressure chamber 33b is reduced by the increase of the volume of the second pressure chamber 33b. Along with this, the first check valve V1 is closed and the second check valve V2 is opened, and the oil 83 of the first pressure chamber 33a is transferred to the second pressure chamber 33b via the second check valve V2. To flow.

As described above, as the piston 40 reciprocates along the axial direction DL, the oil 83 sucked into the pressure chamber 33 from the suction port 31 is discharged from the discharge port 32 to the outside of the pressure chamber 33. Next, the configuration of the actuator 2 that generates a thrust for moving the piston 40 along the axial direction DL will be described.

As shown in FIG. 1, the actuator 2 is a cylindrical coil body 10 coaxially arranged with the cylinder 30 in the axial direction DL, and a movable body capable of reciprocating in the axial direction DL with respect to the cylindrical coil body 10 It has 20 and. The cylindrical coil body 10 is disposed on the second axial side DL2 with respect to the cylinder 30. The movable body 20 is coupled to the piston 40. Specifically, the movable body 20 is coupled to the piston 40 from the second axial direction DL2 so as to move in the axial direction DL integrally with the piston 40. Further, the movable body 20 is disposed so as to overlap the cylindrical coil body 10 in a radial direction along the radial direction DR. In the present embodiment, the movable body 20 is disposed radially inward of the cylindrical coil body 10 (inside of the radial direction DR). That is, the movable body 20 is configured to reciprocate along the axial direction DL in a space surrounded by the cylindrical coil body 10 from the radial outer side DR2 (the outer side of the radial direction DR).

The cylindrical coil body 10 includes a core 12 formed in a cylindrical shape (here, a cylindrical shape) extending in the axial direction DL, and a coil 11 wound around the core 12. The coil 11 is cylindrically wound around the axis of the core 12, and the cylindrical coil body 10 generates a magnetic flux for driving the movable body 20 in the axial direction DL in a state where the coil 11 is energized. Is configured as. That is, the cylindrical coil body 10 is provided with the coil 11 which generate | occur | produces magnetic flux, and the core 12 which covers the coil 11 by supplying with electricity. In the present embodiment, the cylindrical coil body 10 includes a plurality of coils 11 arranged in the axial direction DL. Specifically, the cylindrical coil body 10 includes two coils 11 (a first coil 11a and a second coil 11b) arranged in the axial direction DL. The two coils 11 adjacent to each other in the axial direction DL flow in current in opposite directions to generate magnetic flux in opposite directions. The two coils 11 adjacent to each other in the axial direction DL are arranged at an interval in the axial direction DL.

In this embodiment, three magnetic poles of the first magnetic pole 12a, the second magnetic pole 12b, and the third magnetic pole 12c are formed at the end of the radially inner side DR1 of the core 12 sequentially from the axial first side DL1. There is. The first magnetic pole 12 a is formed on a portion of the core 12 which is disposed on the first axial side DL 1 with respect to the first coil 11 a and which extends to the radially inner side DR 1. The second magnetic pole 12 b is formed of the core 12 The third magnetic pole 12 c is formed in a portion extending from the portion disposed between the first coil 11 a and the second coil 11 b in the axial direction DL to the radially inner side DR 1, and the third magnetic pole 12 c is a second coil 11 b in the core 12. On the other hand, it is formed in the part extended to radial direction inner side DR1 from the part arrange | positioned at axial direction 2nd side DL2. Then, as described above, when current flows in opposite directions to each other through the first coil 11a and the second coil 11b, the first magnetic pole 12a and the third magnetic pole 12c are magnetized so as to have the same polarity. The magnetic pole 12b is magnetized so as to have an opposite polarity to the first magnetic pole 12a and the third magnetic pole 12c. Therefore, by switching the direction of the current flowing through the first coil 11a and the second coil 11b, the first magnetic pole 12a and the third magnetic pole 12c act as the N pole and the second magnetic pole 12b acts as the S pole. It is switched to the state where the first magnetic pole 12a and the third magnetic pole 12c act as the S pole and the second magnetic pole 12b acts as the N pole.

The movable body 20 is driven toward at least one side in the axial direction DL by the magnetic flux generated from the cylindrical coil body 10. Here, the movable body 20 is driven toward both sides in the axial direction DL by the magnetic flux generated from the cylindrical coil body 10. Specifically, the movable body 20 is driven toward both sides in the axial direction DL by switching the energization direction of the coil 11 of the cylindrical coil body 10. That is, the movable body 20 is driven toward both sides in the axial direction DL by repeating switching of the direction of the current supplied to the cylindrical coil body 10. Since the movable body 20 is connected to the piston 40, the piston 40 reciprocates along the axial direction DL by driving the movable body 20 toward both sides in the axial direction DL.

In order to enable the movable body 20 to be driven toward both sides in the axial direction DL by the magnetic flux generated from the cylindrical coil body 10, the movable body 20 is provided with a permanent magnet M. The permanent magnet M is provided on the movable body 20 in such a manner that the thrust of the movable body 20 can be obtained by the interaction between the magnetic flux generated from the permanent magnet M and the magnetic flux generated from the cylindrical coil body 10. In the present embodiment, the movable body 20 includes the shaft member 21 extending in the axial direction DL, and the permanent magnet M formed in a cylindrical shape (here, a cylindrical shape) coaxial with the shaft member 21 is the shaft member 21. It is fixed to the outer peripheral surface of. And in this embodiment, permanent magnet M is magnetized by radial direction DR.

In the present embodiment, the movable body 20 includes a plurality of permanent magnets M arranged in the axial direction DL. Specifically, the movable body 20 includes two permanent magnets M (a first permanent magnet M1 and a second permanent magnet M2) arranged side by side in the axial direction DL. That is, the movable body 20 includes the same number of permanent magnets M as the number of the coils 11 provided in the cylindrical coil body 10. Two permanent magnets M adjacent to each other in the axial direction DL are magnetized in opposite directions to each other in the radial direction DR. Further, two permanent magnets M adjacent to each other in the axial direction DL are arranged at an interval in the axial direction DL. Here, as shown in FIGS. 1 to 3, regardless of the position of the movable body 20 in the axial direction DL, the first permanent magnet M1 is disposed to face the first coil 11a in the radial direction DR, The two permanent magnets M2 are disposed to face the second coil 11b in the radial direction DR. In addition, regardless of the position of the movable body 20 in the axial direction DL, the first permanent magnet M1 has a portion of the axial first side DL1 facing the first magnetic pole 12a in the radial direction DR and the axial second side DL2 Is disposed so as to face the second magnetic pole 12b in the radial direction DR. Regardless of the position of the movable body 20 in the axial direction DL, the second permanent magnet M2 has a portion on the axial first side DL1 facing the second magnetic pole 12b in the radial direction DR and a portion on the axial second side DL2 Are arranged to face the third magnetic pole 12 c in the radial direction DR.

Since the actuator 2 is configured as described above, when currents flowing in opposite directions flow through the first coil 11a and the second coil 11b, the movable body 20 moves in the axial direction DL by the magnetic flux generated from the cylindrical coil body 10. It is driven toward one side. Further, when the direction of the current flowing through the first coil 11a is reversed and the direction of the current flowing through the second coil 11b is reversed, the movable body 20 is moved to the other side in the axial direction DL by the magnetic flux generated from the cylindrical coil body 10. Drive towards. Therefore, by switching the direction of energization of the coil 11 (here, the first coil 11a and the second coil 11b), the movable body 20 and the piston 40 coupled thereto can be reciprocated along the axial direction DL. it can.

By the way, the discharge flow rate (discharge amount per unit time) of the oil 83 by the hydraulic pump 1 is the stroke amount of the piston 40 (movement amount of the piston 40 along the axial direction DL) and the stroke number of the piston 40 per unit time It depends on and. Specifically, as the stroke amount of the piston 40 increases, the volume change amount of the pressure chamber 33 accompanying the reciprocation of the piston 40 increases, and the discharge amount of the oil 83 accompanying one reciprocation of the piston 40 increases. Become. Further, as the number of strokes of the piston 40 per unit time increases, the number of times the oil 83 is discharged per unit time increases.

Regarding this point, as described above, in the hydraulic pump 1, the actuator 2 for driving the pump unit 3 drives the movable body 20 toward both sides in the axial direction DL by the magnetic flux generated from the cylindrical coil body 10. Is configured. Therefore, compared with the case where the movable body 20 is driven only to one side in the axial direction DL by the magnetic flux generated from the cylindrical coil body 10, the stroke amount of the movable body 20 capable of appropriately generating thrust. The actuator 2 is easy to configure so that Therefore, the stroke amount of the piston 40, which is determined according to the stroke amount of the movable body 20, can easily be increased to such an extent that a desired discharge flow rate can be obtained.

Further, in the hydraulic pump 1, the movable body 20 driven by the magnetic flux generated from the cylindrical coil body 10 includes the permanent magnet M. Therefore, the number of turns of the coil 11 required to obtain a desired thrust can be reduced as compared with the case where the movable body 20 is not provided with the permanent magnet M. Therefore, the inductance of the coil 11 can be reduced to improve the current response of the actuator 2, and as a result, a desired discharge flow rate can be obtained for the drive frequency of the actuator 2 that determines the number of strokes of the piston 40 per unit time. It is easy to raise to some extent.

Further, in the present embodiment, the hydraulic pump 1 is disposed such that the actuator 2 is used in the air environment. Therefore, since the movable body 20 can be reciprocated along the axial direction DL in a space not filled with the oil 83, viscosity and the like of the oil 83 when the movable body 20 reciprocates along the axial direction DL It is possible to keep the resulting sliding resistance small and secure a large stroke amount of the movable body 20. When the amount of heat generation of the actuator 2 is large and it is necessary to cool the actuator 2 with the oil 83, it is necessary to use the actuator 2 under the environment in oil, but in the hydraulic pump 1, as described above It is possible to reduce the number of turns of the coil 11 required to obtain a desired thrust. As a result, the amount of heat generation of the actuator 2 can be easily reduced to such an extent that the actuator 2 can be used in the air environment.

In the present embodiment, as an example, the pump unit 3 is configured to generate the hydraulic pressure required by the drive device 81 housed in the case 80 as shown in FIG. The driving device 81 is disposed in a housing space 80 a formed inside the case 80. The drive device 81 is, for example, a drive device for a vehicle mounted on a vehicle, such as a stepped or continuously variable automatic transmission, a manual transmission, or a drive transmission device for a hybrid vehicle or an electric vehicle. In this case, the driving device 81 is configured to transmit the driving force (torque) between the driving force source of the wheel and the wheel. Moreover, the drive device 81 includes, for example, a rotating electrical machine as a driving force source of wheels. In the case where a hydraulic pressure required for lubrication or cooling of each part of the drive unit 81 is provided as the hydraulic pressure required by the drive unit 81, or the drive unit 81 is provided with a device (such as an engagement device) operated by the hydraulic pressure. The hydraulic pressure required for actuation or preparation for actuation can be illustrated. The oil discharged from the hydraulic pump 1 is supplied to a portion of the drive device 81 requiring oil pressure via the discharge oil passage 86. The oil discharged from the hydraulic pump 1 may be supplied to a portion of the drive device 81 that requires the hydraulic pressure after the hydraulic pressure is controlled by a hydraulic control device (not shown).

As shown in FIG. 5, the pump unit 3 (specifically, the suction port 31, see FIG. 1) is configured to suck the oil 83 stored in the oil storage unit 82 inside the case 80. It is located inside. Here, the oil reservoir 82 is formed at the bottom of the case 80, and the suction port 31 is arranged to suction the oil 83 stored in the oil reservoir 82 via the suction oil passage 85. . On the other hand, the actuator 2 is disposed outside the case 80, which makes it possible to use the actuator 2 in the air environment. In addition, that the actuator 2 is disposed outside the case 80 means that at least a part of the actuator 2 (at least a portion of the second side DL2 in the axial direction) is disposed outside the case 80, A part (a part of the axial direction first side DL1) may be disposed inside the case 80. That is, at least a part of the actuator 2 is disposed outside the case 80. In addition, in FIG. 5, the case where the hydraulic pump 1 is arrange | positioned by the direction which the axial direction DL follows a horizontal surface is illustrated.

Here, the case where the actuator 2 is used in the air environment by disposing the actuator 2 outside the case 80 has been exemplified, but in the inside of the case 80, the oil surface 84 of the oil reservoir 82 is used. The actuator 2 may be configured to be used in an air environment or an environment close to the air environment by disposing the actuator 2 above (above the vertical direction Z). The vertical direction Z means the vertical direction when the hydraulic pump 1 is in use, and here means the vertical direction when the case 80 is mounted on a vehicle. At least a part of the pump unit 3 (for example, the suction port 31) may be disposed below the oil surface 84 of the oil reservoir 82 (downward in the vertical direction Z). The oil level 84 of the oil reservoir 82 is, for example, the highest oil level within the range of change of the oil level 84 of the oil reservoir 82, or the hydraulic pump 1 is in operation and the oil level of the hydraulic pump 1 is The oil surface 84 of the oil reservoir 82 in a stable state can be obtained. In the example shown in FIG. 5, the actuator 2 is disposed outside the case 80, and both the actuator 2 and the pump unit 3 are disposed above the oil surface 84 of the oil reservoir 82.

As shown in FIG. 1, in the present embodiment, the oil of the pressure chamber 33 further infiltrates into the facing portion 2 a where the cylindrical coil body 10 and the movable body 20 oppose in the radial direction DR, and the sliding of the movable body 20 In order to suppress an increase in resistance, an oil blocking structure 5 is provided between the opposing portion 2a and the pressure chamber 33 in the axial direction DL to block the entry of oil 83 from the pressure chamber 33. In the present embodiment, the oil shutoff structure 5 includes an intermediate chamber 60 partitioned between the pressure chamber 33 and the pressure chamber 33 in an oil-tight manner using the first seal member S1 between the pressure chamber 33 and the actuator 2 in the axial direction DL. Have. That is, the intermediate chamber 60 is partitioned from the pressure chamber 33. The intermediate chamber 60 is provided between the pressure chamber 33 and the facing portion 2 a of the actuator 2 in the axial direction DL.

Specifically, the first wall 61 which is a wall of the first axial side DL1 of the intermediate chamber 60 is formed by the cylinder 30 (specifically, the cylindrical portion 34), and the first wall 61 of the cylinder 30 A first through hole 61 a through which the first portion 51 of the piston 40 passes is formed in a portion forming the portion 61. The outer peripheral surface of the first portion 51 and the inner peripheral surface of the first through hole 61a are formed to divide the pressure chamber 33 (specifically, the second pressure chamber 33b) and the intermediate chamber 60 in an oil tight manner. A first seal member S1 (annular seal member) for sealing the gap is provided on the outer peripheral surface of the first portion 51.

On the other hand, the second wall 62 which is a wall of the axial second side DL 2 of the intermediate chamber 60 is formed by the cylindrical coil body 10 (specifically, the core 12), and the second wall 62 in the cylindrical coil body 10 In the portion forming the wall 62, a second through hole 62a through which the second portion 52 of the movable body 20 penetrates is formed. The second portion 52 of the movable body 20 is connected to the first portion 51 of the piston 40 at the intermediate chamber 60. That is, the connecting portion 53 between the first portion 51 and the second portion 52 is disposed in the intermediate chamber 60. Each of the first portion 51 and the second portion 52 is formed to have a cylindrical (here, cylindrical) outer peripheral surface extending in the axial direction DL. Note that, between the second through hole 62a and the second portion 52, a first closing member B1 (here, a portion between the inner circumferential surface of the second through hole 62a and the outer circumferential surface of the second portion 52). Bush) is arranged. As used herein, "occluding" means closing at least a portion of the gap.

In the present embodiment, the third wall 63 which is a wall of the radially outer side DR2 of the intermediate chamber 60 is formed by the cylindrical coil body 10 (specifically, the core 12). In the part forming the three walls 63, the discharge port 7 penetrating the part in the radial direction DR is formed. That is, the intermediate chamber 60 is opened to the external space 6 which is the space outside the actuator 2 through the discharge port 7. Although illustration is abbreviate | omitted in FIG. 5, the discharge port 7 is arrange | positioned inside the case 80 in the example shown in FIG. Therefore, in the example shown in FIG. 5, the accommodation space 80 a formed inside the case 80 is the external space 6. The third wall 63 may be formed of a member (for example, a cylinder 30) different from the cylindrical coil body 10, and the discharge port 7 may be provided in a portion of the member where the third wall 63 is formed.

As described above, in the present embodiment, the intermediate chamber 60 is provided between the pressure chamber 33 (specifically, the second pressure chamber 33 b) and the actuator 2 (the facing portion 2 a) in the axial direction DL, and 60 is oil-tightly partitioned from the pressure chamber 33 using the first seal member S1. Thereby, the first seal member S1 can regulate the oil 83 from leaking from the pressure chamber 33 to the axial second side DL2, and even if such an oil 83 leaks, It is possible to cause the oil 83 to flow into the intermediate chamber 60 instead of the inside of the actuator 2 (the facing portion 2a). Furthermore, in the present embodiment, since the intermediate chamber 60 is opened to the external space 6, even if the oil 83 flows into the intermediate chamber 60, the oil 83 is not contained in the inside of the actuator 2 (facing portion It is possible to discharge to the external space 6 without flowing into 2a), that is, to block the entry of the oil 83 into the inside (the facing portion 2a) of the actuator 2.

In the present embodiment, in order to further reduce the volume change of the intermediate chamber 60 in a state in which the movable body 20 and the piston 40 reciprocate along the axial direction DL (that is, at the time of operation of the hydraulic pump 1), The outer peripheral surface of the first portion 51 and the outer peripheral surface of the second portion 52 are formed to have the same diameter. As a result, the variation of the pressure in the intermediate chamber 60 can be reduced, and the pressure difference between the intermediate chamber 60 and the inside of the actuator 2 (opposite portion 2a) can be kept small. 83 is configured to be hard to infiltrate into the inside of the actuator 2 (opposite portion 2a). Although the diameters of the outer peripheral surface of the first portion 51 and the outer peripheral surface of the second portion 52 may be different, even in this case, the outer peripheral surface of the first portion 51 and the second portion 52 It is preferable to minimize the difference in diameter with the outer peripheral surface as much as possible and to minimize the volume change of the intermediate chamber 60 as much as possible. In addition, the structure of the oil blocking structure 5 shown here is an example, and it is possible to change the structure of the oil blocking structure 5 suitably. In addition, when the leakage of the oil 83 from the pressure chamber 33 to the axial second side DL2 does not cause a problem, the hydraulic pump 1 may not be provided with the oil shutoff structure 5.

As described above, the first closing member B1 is disposed between the second through hole 62a and the second portion 52. Further, the actuator 2 is configured such that the third portion 23, which is a portion of the second side DL2 in the axial direction than the second portion 52 of the movable body 20, is inserted into the second side DL2 in the axial direction than the second through hole 62a. A third through hole 13 is provided, and the second through hole 13 is closed between the inner peripheral surface of the third through hole 13 and the outer peripheral surface of the third portion 23 between the third through hole 13 and the third portion 23. A closing member B2 (here, a bush) is disposed. Since the first closing member B1 and the second closing member B2 function as a seal, the entry of the oil 83 into the inside of the actuator 2 can be effectively suppressed on both sides in the axial direction DL. There is. In the present embodiment, the third portion 23 is a portion on the second side DL2 in the axial direction of the permanent magnet M (here, the first permanent magnet M1 and the second permanent magnet M2) in the movable body 20. Here, the third portion 23 constitutes an end portion of the movable body 20 on the second axial side DL2. The third portion 23 is smaller in diameter than the third portion 23 of the movable body 20 than the portion on the first axial side DL1 (here, the portion provided with the permanent magnet M). And the 3rd penetration hole 13 is formed in the end of axial direction 2nd side DL2 in cylindrical coil object 10 (specifically, core 12). Here, the third through hole 13 is a wall of the axial direction second side DL2 of the accommodation chamber of the movable body 20 formed inside the actuator 2 in the cylindrical coil body 10 (specifically, the core 12). It is formed in the part to form.

Next, a configuration for reducing energy consumption of the actuator 2 in the hydraulic pump 1 according to the present embodiment will be described.

As shown in FIG. 1, the hydraulic pump 1 has a first biasing member 71 for biasing the piston 40 toward the first axial side DL1, and a second biasing member for biasing the piston 40 toward the second axial side DL2. A biasing member 72 is provided. Here, the first biasing member 71 is provided to bias the piston 40 toward the first axial side DL1 regardless of the position of the piston 40 in the axial direction DL, and the second biasing member 72 is a piston The piston 40 is provided so as to bias the piston 40 toward the second axial side DL2 regardless of the position of the axial direction DL. Then, as described below, the hydraulic pump 1 reciprocates the piston 40 along the axial direction DL by using the resonance phenomenon of the piston 40 by the first biasing member 71 and the second biasing member 72. It is configured to let you That is, the first biasing member 71 and the second biasing member 72 are biasing members that bias the piston 40 in the axial direction DL, and function as resonance biasing members for causing the piston 40 to resonate. In this hydraulic pump 1, by compensating the thrust generated by the actuator 2 by the resonance phenomenon of the piston 40, it is possible to reduce the energy consumption of the actuator 2 for generating the thrust required of the piston 40. It has become.

As shown in FIG. 1, in the present embodiment, the first biasing member 71 is disposed on the second side DL2 in the axial direction with respect to the first part 51 of the piston 40, and the first portion 51 in the axial direction first side DL1. It is arranged to be biased. Here, the first biasing member 71 is disposed in the intermediate chamber 60. Specifically, the first biasing member 71 is provided to exert a biasing force on the piston 40 (specifically, the first portion 51) and the core 12. The first biasing member 71 is formed such that the diameter of the first axial side DL1 is smaller than the diameter of the second axial side DL2. Thereby, even when the outer peripheral surface of the first portion 51 and the outer peripheral surface of the second portion 52 are formed to have the same diameter, the piston 40 (specifically, the first portion 51) and the core 12 (the first portion 51). Specifically, it is possible to provide the first biasing member 71 so as to apply a biasing force to the second portion 52 and the outer portion of the radial direction DR. A coil spring can be used as the first biasing member 71. In this case, the first biasing member 71 is disposed in a state in which the expansion and contraction direction follows the axial direction DL and is compressed more than the natural length.

Further, in the present embodiment, the second biasing member 72 is located on the first axial side DL1 with respect to the main body portion 41 of the piston 40 (here, the piston 40 and the first check valve V1 in the axial direction DL ), The body portion 41 is arranged to be biased toward the second axial side DL2. Here, the second biasing member 72 is disposed in the first pressure chamber 33a. Specifically, the second biasing member 72 is opposite to the piston 40 (specifically, the main body 41) inside the pressure chamber 33 and the side of the actuator 2 in the axial direction DL of the cylinder 30 (ie, An urging force is applied to the end of the first axial side DL1). A coil spring can be used as the second biasing member 72. In this case, the second biasing member 72 is disposed in a state in which the expansion and contraction direction follows the axial direction DL and is compressed more than the natural length.

As described above, in the present embodiment, the first biasing member 71 and the second biasing member 72 are disposed separately on at least a part of the piston 40 on both sides in the axial direction DL. Specifically, the first biasing member 71 and the second biasing member 72 are divided into both sides in the axial direction DL with respect to the main body portion 41, the first portion 51, and the portion therebetween in the piston 40. Are arranged. And in this embodiment, the 1st biasing member 71 and the 2nd biasing member 72 are arrange | positioned so that it may not overlap with the discharge port 32 in the radial direction view. That is, both the first biasing member 71 and the second biasing member 72 are disposed so as not to inhibit the flow of the oil 83 discharged from the discharge port 32, whereby the flow path resistance at the discharge port 32 is obtained. Is kept low. Here, the first biasing member 71 is disposed in the intermediate chamber 60, the second biasing member 72 is disposed in the first pressure chamber 33a, and the discharge port 32 is provided in communication with the second pressure chamber 33b. The first urging member 71 and the second urging member 72 do not overlap with the discharge port 32 in the radial direction.

In the present embodiment, the actuator 2 is configured to reciprocate the movable body 20 along the axial direction DL at a set drive frequency. That is, the control unit 90 is configured to control the actuator 2 such that the movable body 20 reciprocates along the axial direction DL at the set drive frequency. The control unit 90 is configured to control the actuator 2 via a drive circuit (specifically, a single-phase inverter circuit) which is not shown. For example, the control unit 90 controls the drive circuit such that an AC voltage having a set drive frequency is applied to the actuator 2 (specifically, the coil 11).

The drive frequency of the actuator 2 is set according to the diameter of the piston 40 and the stroke amount of the piston 40 so as to obtain the required discharge flow rate of the oil 83. For example, the drive frequency of the actuator 2 is set so as to obtain a target discharge flow rate corresponding to the required flow rate of the automatic transmission which is determined according to the traveling state of the vehicle (for example, at the time of shifting, steady traveling etc.). The vibration system including the piston 40, the first biasing member 71, and the second biasing member 72 becomes in a resonant state as the movable body 20 reciprocates, so that the first biasing member 71 and the second biasing member The combined spring constant with the biasing member 72 is set based on the drive frequency. That is, in the actuator 2, the vibration system including the piston 40, the first biasing member 71, and the second biasing member 72 has an axis at the movable body 20 at a driving frequency at which the resonant state occurs as the movable body 20 reciprocates. Reciprocate along the direction DL. The pump unit 3 (specifically, the movable body 20) is driven at a drive frequency that can ensure the target discharge flow rate of the pump unit 3 (the target discharge flow rate of the hydraulic pump 1). The vibration system also includes the movable body 20. When the drive frequency of the actuator 2 is set to be variable, the drive frequency for setting the combined spring constant can be, for example, the drive frequency with the highest frequency of use.

The equation of motion of the piston 40 in the hydraulic pump 1 can be expressed by the equation of motion of damped forced vibration as described below. And, as shown in the following equation (9), in the present embodiment, the mass of the entire movable portion 4 that reciprocates along the axial direction DL at the drive frequency, including the piston 40 and the movable body 20 A value obtained by multiplying the target mass (W) by the square of the angular frequency (ω) corresponding to the drive frequency as the combined spring constant (K) of the first biasing member 71 and the second biasing member 72 as a mass Is set as the standard. Here, "setting a certain value as a reference" is a concept including both setting to the value and setting the value to the adjusted value. Therefore, the synthetic spring constant of the 1st energizing member 71 and the 2nd energizing member 72 makes the reference value the value which multiplied the object mass to the square of the angular frequency (driving angular frequency) according to driving frequency. It is set to a reference value or set to a value obtained by adjusting the reference value. In the latter case, for example, from the angular frequency ω ₀ represented by the following equation (8) of the actual resonant angular frequency of the vibration system including the piston 40, the first biasing member 71, and the second biasing member 72. The combined spring constant of the first biasing member 71 and the second biasing member 72 can be set to a value obtained by adjusting the above-mentioned reference value, in consideration of the deviation of the above.

Hereinafter, the equation of motion of the piston 40 will be described. Here, the entire mass of the movable part 4 is W, the thrust is F _m , the viscous drag by the oil 83 and the sliding resistance of the movable part 4 c _μ , the hydraulic pressure is P, the pressure receiving area of the piston 40 is S, the first bias Assuming that the synthetic spring constant of the member 71 and the second biasing member 72 is K and the displacement of the piston 40 is x, the equation of motion of the piston 40 can be expressed by the following equation (1) using a code function sgn.

The circuit equation of the electric circuit regarding energization to the coil 11 is represented by the following equation (2) with voltage V, electric resistance of the circuit R, current I, inductance of the circuit L and back electromotive force constant k _e Be done.

The relationship between the thrust F _m and the current I is expressed by the following equation (3), where k _F is a thrust constant.

As shown in the equation (4), the thrust constant k _F and the back electromotive force constant k _e are equal, the voltage amplitude is V _a , and the driving angular frequency of the actuator 2 (here, the voltage angular frequency) is ω, the following expression A voltage command can be assumed as shown in (5). Here, the influence of back electromotive force and oil pressure is ignored.

As mentioned above, it will become following formula (6) if the equation of motion of Formula (1) is put together. In addition, since the inductance L of the circuit is small due to its structure, the inductance L is neglected and considered here.

Equation (6) is an equation of motion of damped forced vibration, and this equation of motion has a steady-state vibration solution as shown by the following Equation (7) and Equation (8).

FIG. 4 is a characteristic diagram showing the relationship between the angular frequency ratio (ω / ω ₀ ) and the amplitude ratio (X _a / X _s ). Here, X _s is a static displacement amount, which is a value obtained by dividing the amplitude (k _F V _a / R) on the right side of Formula (6) by the synthetic spring constant K. From FIG. 4, the equation (7), and the equation (8), it can be seen that the amplitude ratio is maximum when “ω = ω ₀ ”. If this condition is satisfied, the movable portion 4 can be reciprocated along the axial direction DL even with a low thrust. By utilizing the resonance as described above, the efficiency of the hydraulic pump 1 can be improved, the power consumption can be reduced, and the actuator 2 can be miniaturized.

The amplitude ratio is maximized when “ω = ω ₀ ”, but as shown in equation (8), the angular frequency ω ₀ is obtained by dividing the composite spring constant K by the mass W of the entire movable part 4 and taking the square root Value. In other words, the combined spring constant K is a value obtained by multiplying the square of the driving angular frequency ω by the mass W of the entire movable portion 4 so that “ω = ω ₀ ” as shown in the following equation (9) It is preferable that it is set. Based on this point, in the present embodiment, as described above, the combined spring constant of the first biasing member 71 and the second biasing member 72 is set to the square of the driving angular frequency, and the target mass (the entire movable portion 4 is Is set based on the value obtained by multiplying the mass of

Here, the sum of the spring constant of the first biasing member 71 and the spring constant of the second biasing member 72 is the combined spring constant K of the first biasing member 71 and the second biasing member 72. For example, the spring constant of the first biasing member 71 and the spring constant of the second biasing member 72 can be set to the same value (that is, a half value of the combined spring constant K). Alternatively, the spring constant of the first biasing member 71 and the spring constant of the second biasing member 72 may be made different from each other so that the total of these spring constants is the above-described synthetic spring constant K. .

When the drive frequency of the actuator 2 is increased to increase the number of times the oil 83 is discharged per unit time, the resonant frequency needs to be increased in accordance with the drive frequency of the actuator 2 in order to effectively use the resonance phenomenon. That is, it is necessary to increase the spring constant of the entire vibration system. In this regard, the hydraulic pump 1 is provided with two resonance biasing members (71, 72) for biasing the piston 40 to opposite sides in the axial direction DL as a resonance biasing member for generating a resonance phenomenon. ) Is provided. Therefore, compared with the case where only one resonance biasing member is provided, it is easy to secure a large spring constant of the entire vibration system.

As described above, in the hydraulic pump 1, the control unit 90 is configured to control the actuator 2 such that the movable body 20 reciprocates along the axial direction DL at the set drive frequency. Further, in the present embodiment, two resonance biasing members of a first biasing member 71 and a second biasing member 72 are provided as a resonance biasing member for biasing the piston 40 in the axial direction DL, The combined spring constant of the first biasing member 71 and the second biasing member 72 is obtained by multiplying the square of the driving angular frequency (the angular frequency corresponding to the driving frequency) by the target mass (the mass of the entire movable portion 4) It is set based on the value. Therefore, the resonant angular frequency ω ₀ of the vibration system including the piston 40, the first biasing member 71 and the second biasing member 72 has a value represented by the above equation (8) (the combined spring constant K is a movable portion 4) In the case where the values are the same or substantially the same as the square root value divided by the total mass W, the resonance phenomenon of the piston 40 is effectively used to effectively reduce the energy consumption of the actuator 2 In other words, the efficiency of the actuator 2 can be effectively enhanced.

On the other hand, when the resonant angular frequency ω ₀ of the vibration system deviates from the value represented by the above equation (8), the efficiency of the actuator 2 increases as the deviation between the driving angular frequency ω and the resonant angular frequency ω ₀ increases. descend. Even if such a driving angular frequency omega is not identical to the resonance angular frequency omega _0, if there is no large shift of the driving angular frequency omega and the resonance angular frequency omega _0, the resonance phenomenon of the piston 40 but not optimal The efficiency of the actuator 2 can be improved by utilizing it. However, in order to use the resonance phenomenon of the piston 40 as effectively as possible, it is desirable that the drive angular frequency ω be set to a value close to the resonant angular frequency ω ₀ .

The present inventors use the spring constant of the oil 83 in the pressure chamber 33 as a spring when the resonance angular frequency ω ₀ deviates from the value represented by the equation (8). I focused on it. The oil 83 inside the pressure chamber 33 is compressed and expanded along with the reciprocation of the piston 40 along the axial direction DL, so the oil 83 can be regarded as a spring. Then, as a result of research, the present inventors have changed the spring constant of the oil 83 in the pressure chamber 33 according to the operating state of the pump unit 3 to thereby affect the efficiency of the actuator 2. We have found that the resonant frequency of Based on such knowledge, the control unit 90 sets the drive frequency to the resonance frequency of the vibration system including the piston 40 and the resonance biasing member (here, the first biasing member 71 and the second biasing member 72). The drive frequency is configured to be different according to the operating state of the pump unit 3 so as to approach (that is, the drive angular frequency ω approaches the resonant angular frequency ω ₀ ). Specifically, the control unit 90 sets the resonance frequency of the vibration system including the piston 40, the movable body 20, and the resonance biasing member (here, the first biasing member 71 and the second biasing member 72) to oil. The actuator 2 is configured to determine the corrected resonance frequency corrected according to the influence (in the present embodiment, the oil temperature T or the discharge pressure P), and reciprocate the movable body 20 along the axial direction DL at the corrected resonance frequency. Is configured to control. That is, the control unit 90 sets the correction resonance frequency to the drive frequency. Thus, when the resonance frequency of the vibration system changes in accordance with the operating state of the pump unit 3, the efficiency of the actuator 2 can be maintained high in accordance with the resonance frequency after the change of the drive frequency. . That is, when the resonance frequency of the vibration system changes due to the influence of oil 83, it is possible to drive the actuator 2 at the corrected resonance frequency which is the resonance frequency after the change.

In the present embodiment, the oil temperature T and the discharge pressure P of the oil 83 from the discharge port 32 are considered as the operating state of the pump unit 3 that can change the resonance frequency of the vibration system. FIG. 6 corresponds to one in which the horizontal axis of the characteristic diagram of FIG. 4 is replaced with the angular frequency ratio (ω / ω ₀ ) to make the angular frequency (ω), and the amplitude ratio (X _a at different four oil temperatures T) The simulation result of / X _s ) is shown. Here, the oil temperature T decreases in the order of “T1”, “T2”, “T3”, and “T4”. As apparent from FIG. 6, it can be seen that the resonant angular frequency ω ₀ tends to decrease as the oil temperature T decreases. Since oil has a large temperature dependence of viscosity compared to a gas such as air, it can be inferred that the resonance angular frequency ω ₀ changes in this manner relatively relatively to the oil temperature T. In view of such a tendency, the control unit 90 is configured to lower the drive frequency as the oil temperature T decreases. That is, the control unit 90 is configured to lower the correction resonance frequency as the oil temperature T decreases. As a result, when the resonance frequency of the vibration system changes according to the oil temperature T that is the operating state of the pump unit 3, it is possible to match the drive frequency to the resonance frequency after the change. The control unit 90 acquires the oil temperature T from an oil temperature sensor (shown), and determines a drive frequency according to the oil temperature T with reference to, for example, a map. That is, the control unit 90 determines a corrected resonance frequency corresponding to the oil temperature T with reference to, for example, a map. As schematically shown in FIG. 7, in the map to which the control unit 90 refers, for example, the relationship between the oil temperature T and the driving angular frequency ω is such that the driving angular frequency ω decreases as the oil temperature T decreases. It is prescribed.

On the other hand, although the illustration of the characteristic diagram is omitted, the discharge pressure P of the oil 83 from the discharge port 32 is increased when the target discharge pressure becomes high according to the traveling state of the vehicle (for example, The pressure is low, the discharge pressure at idle stop is high during traveling, etc.), and as the discharge pressure P increases, the resonant angular frequency ω ₀ tends to decrease. In view of such a tendency, the control unit 90 is configured to lower the drive frequency as the discharge pressure P becomes higher. That is, the control unit 90 is configured to lower the correction resonance frequency as the discharge pressure P becomes higher. Thus, when the resonance frequency of the vibration system changes according to the discharge pressure P which is the operating state of the pump unit 3, it is possible to match the drive frequency to the resonance frequency after the change. The control unit 90 obtains the discharge pressure P from a discharge pressure sensor (shown), and determines a drive frequency corresponding to the discharge pressure P with reference to, for example, a map. That is, the control unit 90 determines a corrected resonant frequency corresponding to the discharge pressure P with reference to, for example, a map. As schematically shown in FIG. 8, in the map to which the control unit 90 refers, for example, the relationship between the discharge pressure P and the drive angular frequency ω is such that the drive angular frequency ω decreases as the discharge pressure P increases. It is prescribed.

In the present embodiment, the first control in which the control unit 90 lowers the drive frequency as the oil temperature T decreases (that is, control in which the correction resonance frequency decreases as the oil temperature T decreases), and the discharge pressure P is higher. Therefore, the control unit 90 is configured to perform both of the second control (that is, the correction resonance frequency is lowered as the discharge pressure P becomes higher) that lowers the drive frequency accordingly. Alternatively, only one of the second control and the second control may be performed. Further, in the present embodiment, the oil temperature T and the discharge pressure P are taken into consideration as the operating state (impact of oil) of the pump unit 3 capable of changing the resonance frequency of the vibration system. The drive frequency may be determined in consideration of the operating state (oil influence). For example, third control (that is, control to lower the correction resonance frequency as the viscosity of oil 83 increases), the control unit 90 decreases the drive frequency as the viscosity of oil 83 increases, alone or as described above It may be configured to be executed together with at least one of the first control and the second control.

As described above, in the hydraulic pump 1, the stroke amount of the piston 40, which is determined according to the stroke amount of the movable body 20, can be easily increased to such an extent that a desired discharge flow rate can be obtained. The driving frequency of the actuator 2 for determining the number of strokes can be easily increased to such an extent that a desired discharge flow rate can be obtained. Furthermore, there is a hydraulic pump (hereinafter referred to as “electric oil pump”) that uses an AC rotating electrical machine driven by AC power (for example, three-phase AC power) of multiple phases as a driving power source of the pump unit. The hydraulic pump 1 also has an advantage of being able to realize the same discharge flow rate as the electric oil pump at lower cost. That is, since the actuator 2 used in the hydraulic pump 1 can reduce the number of coils and the number of permanent magnet poles compared to the AC rotating electric machine used in the electric oil pump, the cost can be reduced. . In addition, although it is necessary to drive the electric oil pump by the drive circuit of the number of phases corresponding to the AC rotating electric machine, the hydraulic pump 1 can be driven by the drive circuit of single phase. It is possible to reduce the Describing the specific example, the drive circuit 91 of the actuator 2 used in the hydraulic pump 1 is configured using, for example, an inverter circuit as illustrated in FIG. On the other hand, drive circuit 91 of rotary electric machine MG used in the electric oil pump is configured using an inverter circuit as illustrated in FIG. Here, the rotary electric machine MG is a rotary electric machine driven by three-phase alternating current, and the rotary electric machine MG includes phase coils 93 corresponding to each of the three phases. As apparent from comparison of FIG. 9 with FIG. 10, in the hydraulic pump 1, the number of switching elements 92 provided in the drive circuit 91 can be reduced, and hence the drive circuit 91 can be simplified.

Other Embodiments
Next, other embodiments of the hydraulic pump will be described.

(1) In the above embodiment, the configuration in which the first biasing member 71 is disposed in the intermediate chamber 60 has been described as an example. However, without being limited to such a configuration, the first biasing member 71 may be configured to be disposed at a position different from that of the intermediate chamber 60. For example, the first biasing member 71 may be disposed in the second pressure chamber 33 b to bias the main body 41 of the piston 40 toward the first axial side DL1. In this case, unlike the above embodiment, one of the first biasing member 71 and the second biasing member 72 (specifically, the first biasing member 71) overlaps the discharge port 32 in the radial direction. To be arranged. That is, in the above embodiment, the first biasing member 71 and the second biasing member 72 have been described as an example of the configuration in which they are disposed so as not to overlap the discharge port 32 in the radial direction. Alternatively, at least one of the biasing member 71 and the second biasing member 72 may be disposed so as to overlap the discharge port 32 in the radial direction.

When the first biasing member 71 is disposed at a position different from that of the intermediate chamber 60, the second biasing member 72 may be disposed in the intermediate chamber 60. For example, in the case of using a coil spring as the second biasing member 72, the second biasing member 72 is disposed in the intermediate chamber 60 in a state of being extended more than the natural length, and pivots the first portion 51 of the piston 40. It can be made to urge to direction 2nd side DL2. As described above, when one of the first biasing member 71 and the second biasing member 72 is disposed in the intermediate chamber 60, the intermediate chamber 60 for blocking the entry of the oil 83 into the opposing portion 2a. Can be used effectively. Note that, unlike such a configuration, both the first biasing member 71 and the second biasing member 72 may be disposed at positions different from the intermediate chamber 60.

(2) In the above embodiment, the configuration in which the actuator 2 is used in or near an air environment has been described as an example. However, without being limited to such a configuration, the configuration in which the actuator 2 is used in an oil environment, that is, at least a part of the actuator 2 is disposed below the oil surface 84 of the oil reservoir 82 It can also be configured. In such a case, the hydraulic pump 1 may not be provided with the oil shutoff structure 5.

(3) In the above embodiment, the configuration has been described as an example in which the movable body 20 includes the permanent magnet M magnetized in the radial direction DR. However, without being limited to such a configuration, the movable body 20 includes the permanent magnet M magnetized in the axial direction DL, or the permanent magnet M magnetized in the radial direction DR. And a permanent magnet M which is magnetized in the axial direction DL.

(4) In the above embodiment, the configuration in which the movable body 20 is disposed at the radially inner side DR1 with respect to the cylindrical coil body 10 has been described as an example. However, without being limited to such a configuration, the movable body 20 may be disposed at the radially outer side DR2 with respect to the cylindrical coil body 10.

(5) In the above embodiment, as the resonance biasing member for biasing the piston 40 in the axial direction DL to resonate the piston 40 in the hydraulic pump 1, the first biasing member 71 and the second biasing are used. The configuration in which the member 72 is provided has been described as an example. However, without being limited to such a configuration, the hydraulic pump 1 may be configured to be provided with only one resonance biasing member. In this case, when the piston 40 moves to the first axial side DL1 in the axial direction, the piston 40 is urged to the second axial side DL2 in the axial direction, and when the piston 40 moves to the second axial side DL2 in the axial direction The provision of urging the shaft 40 toward the first axial side DL1 makes it possible to compensate for the thrust generated by the actuator 2 by the resonance phenomenon of the piston 40, as in the above embodiment. In this case, the spring constant of the resonance biasing member may be set to the same value as the combined spring constant in the above embodiment. In the above embodiment, the resonance biasing member is provided to bias the piston 40 in the axial direction DL, but the resonance biasing member moves the movable body 20 in the axial direction DL. It may be provided to bias.

(6) In the above embodiment, the configuration in which the movable body 20 includes the permanent magnet M has been described as an example. However, the movable body 20 can be configured not to include the permanent magnet M without being limited to such a configuration. In this case, for example, a state in which only the first coil 11a of the first coil 11a and the second coil 11b is energized, and a state in which only the second coil 11b of the first coil 11a and the second coil 11b is energized By switching, the movable body 20 can be configured to be driven toward both sides in the axial direction DL. Further, in the above embodiment, the configuration in which the movable body 20 is driven toward both sides in the axial direction DL by the magnetic flux generated from the cylindrical coil body 10 has been described as an example. However, the movable body 20 is not limited to such a configuration, but only by the magnetic flux generated from the cylindrical coil body 10 toward one side (for example, the first side DL1 in the axial direction) of the axial direction DL. It can also be configured to be driven. In this case, for example, the movable body 20 does not have the permanent magnet M. Thus, even in the case where the movable body 20 is driven only to one side in the axial direction DL, the thrust to either one side in the axial direction DL generated by the actuator 2 and the urging for resonance The piston 40 can be reciprocated along the axial direction DL by the biasing force of the axial direction DL by the members (in the above embodiment, the first biasing member 71 and the second biasing member 72).

(7) Note that the configurations disclosed in each of the above-described embodiments may be combined with the configurations disclosed in the other embodiments and applied as long as no contradiction occurs (the embodiments described as the other embodiments Combinations are also possible. As for the other configurations, the embodiments disclosed herein are merely illustrative in all respects. Therefore, various modifications can be made as appropriate without departing from the spirit of the present disclosure.

[Summary of the above embodiment]
Hereinafter, an outline of the hydraulic pump described above will be described.

An actuator (2), a pump unit (3) driven by the actuator (2) to generate a hydraulic pressure, and a control unit (90) controlling the drive of the pump unit (3) by the actuator (2); A hydraulic pump (1) comprising a cylinder (30) having a suction port (31) and a discharge port (32), the pump section (3), the suction port (31) and the discharge port A piston (40) disposed in a pressure chamber (33) formed inside the cylinder (30) in communication with the cylinder (32), and reciprocated along the axial direction (DL) of the cylinder (30) And the actuator (2) is connected to the cylindrical coil body (10) coaxially arranged with the cylinder (30) in the axial direction (DL), and to the piston (40). Said The tubular coil body (10) is disposed so as to overlap with the tubular coil body (10) in a radial direction view (30) along the radial direction (DR), and in the axial direction (DL) with respect to the tubular coil body (10) And a movable body (20) capable of reciprocating movement, wherein the movable body (20) is driven toward at least one side in the axial direction (DL) by magnetic flux generated from the cylindrical coil body (10). And a resonance biasing member (71, 72) for biasing the piston (40) or the movable body (20) in the axial direction (DL), and the control unit (90) is set The actuator (2) is controlled such that the movable body (20) reciprocates along the axial direction (DL) at a drive frequency, and the control unit (90) controls the piston (40), the movable Body (20), the resonance biasing member (71, 72) The resonance frequency of the vibration system is corrected according to the influence of oil, and the correction resonance frequency is determined, and the movable body (20) reciprocates along the axial direction (DL) at the correction resonance frequency. Control the actuator (2).

According to this configuration, the piston (40) can be reciprocated along the axial direction (DL) by utilizing the resonance phenomenon of the piston (40) by the resonance biasing member (71, 72). That is, the thrust generated by the actuator (2) can be compensated by the resonance phenomenon. Thereby, it is possible to reduce the energy consumption of the actuator (2) for generating the thrust required of the piston (40). That is, the efficiency of the actuator (2) can be improved by utilizing the resonance phenomenon of the piston (40).
By the way, as a result of research, when the pump unit (3) is driven by the actuator (2) as a result of research, the piston is a piston compared to the case where the fluid medium is a gas because the fluid medium is oil. It has been found that the resonance frequency of the vibration system including (40) and the resonance biasing member (71, 72) is easily changed by the influence of the oil (83). In addition, when the oil (83) compressed and expanded inside the pressure chamber (33) is regarded as a spring, such a change in resonance frequency causes the spring constant of the oil (83) to be the pump portion (3). Change according to the operating state of the Based on such knowledge, in the above configuration, the control unit (90) reciprocates the actuator (2) so that the movable body (20) reciprocates along the axial direction (DL) at the set drive frequency. When controlling, the resonance frequency of the vibration system including the piston (40), the movable body (20), and the resonance biasing member (71, 72) is corrected according to the influence of oil, and the correction resonance frequency is determined and corrected. The actuator (2) is controlled such that the movable body (20) reciprocates along the axial direction (DL) at the resonance frequency. Thereby, when the resonance frequency of the vibration system changes due to the influence of oil (83), it becomes possible to drive the actuator (2) at the corrected resonance frequency which is the resonance frequency after the change.
Therefore, according to the above configuration, even when the resonance frequency of the vibration system changes, the efficiency of the actuator (2) can be maintained high.

Here, it is preferable that the control unit (90) lowers the corrected resonance frequency as the oil temperature decreases.

According to this configuration, in view of the tendency of the resonance frequency of the vibration system to decrease as the oil temperature decreases, it is possible to appropriately determine the correction resonance frequency in accordance with the change of the oil temperature.

Preferably, the control unit (90) lowers the drive frequency as the discharge pressure of the oil (83) from the discharge port (32) increases.

According to this configuration, in view of the tendency of the resonance frequency of the vibration system to decrease as the discharge pressure of oil (83) from the discharge port (32) increases, the corrected resonance frequency is adjusted according to the change of the discharge pressure. It is possible to determine the

The hydraulic pump which concerns on this indication should just be able to show at least one among each effect mentioned above.

1: hydraulic pump 2: actuator 3: pump unit 10: cylindrical coil body 20: movable body 30: cylinder 31: suction port 32: discharge port 33: pressure chamber 40: piston 71: first biasing member (for resonance Control member)
72: Second biasing member (resonance biasing member)
90: control part DL: axial direction DR: radial direction

Claims

A hydraulic pump comprising: an actuator; a pump unit driven by the actuator to generate hydraulic pressure; and a control unit controlling drive of the pump unit by the actuator.
The pump unit is disposed in a cylinder having a suction port and a discharge port, a pressure chamber formed inside the cylinder so as to communicate with the suction port and the discharge port, and along the axial direction of the cylinder A reciprocating piston;
The actuator is a cylindrical coil body coaxially arranged with the cylinder in the axial direction, and the actuator is connected to the piston and overlaps with the cylindrical coil body in a radial direction along the radial direction of the cylinder And a movable body reciprocably movable in the axial direction with respect to the cylindrical coil body,
The movable body is driven toward at least one side in the axial direction by magnetic flux generated from the cylindrical coil body.
A resonant biasing member is provided for biasing the piston or the movable body in the axial direction;
The control unit controls the actuator such that the movable body reciprocates along the axial direction at a set drive frequency,
The control unit determines a corrected resonance frequency obtained by correcting the resonance frequency of the vibration system including the piston, the movable body, and the resonance biasing member according to the influence of oil, and the movable body is determined by the correction resonance frequency. A hydraulic pump, which controls the actuator to reciprocate along the axial direction.
The hydraulic pump according to claim 1, wherein the control unit lowers the corrected resonance frequency as the oil temperature decreases.
The hydraulic pump according to claim 1, wherein the control unit lowers the corrected resonance frequency as the discharge pressure of oil from the discharge port increases.