JP5906676B2 - Electric oil pump device - Google Patents

Description

  The present invention relates to an electric oil pump device.

  Conventionally, a specific example of an electric oil pump device includes a combination of an oil pump that circulates fluid (oil) and a brushless motor that drives the oil pump. In order to drive a brushless motor, a sensor for detecting the angle (magnetic pole) position of the rotor is required. However, a sensorless sensor that estimates the angular position of the rotor without using the sensor and creates an angular position estimation signal is used. An electric oil pump device using a brushless motor as a drive source has been proposed (see, for example, Patent Document 1). In addition, sensorless driving of a brushless motor that switches the energization timing to the stator windings of each phase of the motor using three-phase induced voltages for creating an angular position estimation signal has been proposed (for example, Patent Document 2). reference).

JP 2002-27776 A JP 2002-325484 A

  In the sensorless drive of the brushless motor as described above, energization of the stator windings of each phase is performed by so-called 120-degree energization in which only a section of 120 degrees out of an electrical angle of 180 degrees between positive and negative voltages is normally performed. In the remaining 60-degree section that is not energized, an induced voltage for each phase is generated at the terminals of the stator windings for each phase. Therefore, when the terminal voltage of the stator winding of each phase in this 60-degree section is compared with the reference voltage, the time when they cross in any phase, that is, the time when the zero cross point is related to the angular position of the rotor As described above, the timing of energizing the stator windings of each phase can be switched. In addition, when the brushless motor is stopped or in a region where the rotational speed is low, it is impossible to detect the angular position of the rotor. I try to switch.

  However, when switching the energization timing, the ringing that occurs due to the transient response during commutation may be erroneously detected as a zero-crossing point, and the time during which this ringing occurs is due to fluctuations in the rotational speed of the brushless motor and the large load. Depending on the situation, there is a possibility that the brushless motor may be out of synchronization or out of step. Furthermore, since the initial angular position of the rotor cannot be estimated, proper energization cannot be performed at startup, and abnormal noise and vibration may occur due to torque fluctuations such as instantaneous torque generation in the reverse rotation direction.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an electric oil pump apparatus including a brushless motor that can be smoothly started and reliably driven by sensorless control.

In order to solve the above-mentioned problem, an invention according to claim 1 is directed to an oil pump, a brushless motor that is provided integrally with the oil pump and rotationally drives the oil pump without a sensor, and an induced voltage of the brushless motor. A controller that detects and estimates the angular position of the rotor and drives and controls the brushless motor, and is provided on a rotating surface of the rotor of the brushless motor that faces the substrate of the controller. Reflected light generated by the detected object, having a plurality of detected objects that reflect external light, and a surface of the substrate that faces the detected object, the infrared light emitting section and the light receiving section. a detection unit by the amount of difference in detecting the presence of the body to be detected, provided on said substrate, detection of the detection object detected by said detecting means It includes an angle calculating means for calculating the estimated angle of the rotor from the turn, and the controller, based on the estimated angle of the rotor calculated by the angle calculating means at the start of the brushless motor, driving and controlling the brushless motor The gist is to do.

According to the above configuration, in the electric oil pump device in which the sensorless brushless motor and the controller are arranged side by side adjacent to the oil pump, the plurality of detection bodies are provided on the rotation surface of the rotor of the brushless motor facing the controller. Then, the detection object is detected by the detection means provided in the controller. The angle calculation means detects the angular position of the rotor from the detection pattern of the detected object detected by the detection means. Controller, based on the estimated angle of the rotor calculated by the angle calculation means of the brushless motor startup, computes the rotation angle and the rotation angular velocity of the rotor. As a result, torque fluctuation due to instantaneous torque in the reverse rotation direction that occurs when the brushless motor is started can be suppressed, and abnormal noise and vibration can be prevented. In addition, step-out due to fluctuations in the rotation speed and load of the brushless motor at the start-up can be prevented. As a result, the brushless motor can be started smoothly and switched to sensorless drive control.

  An electric oil pump device including a brushless motor that can be smoothly started and reliably driven by sensorless control can be provided.

1 is an axial sectional view showing a schematic configuration of an electric oil pump device according to an embodiment of the present invention. The schematic sectional drawing which shows the angle detection part of the rotor in FIG. The front view which shows the angle detection surface of the rotor seen from the arrow A direction in FIG.

Next, an electric oil pump device according to an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is an axial sectional view showing a schematic configuration of an electric oil pump device according to an embodiment of the present invention. As shown in FIG. 1, an electric oil pump device 1 is used as a hydraulic pump for an automobile transmission, and an oil pump (for example, an internal gear pump) 2 and a brushless motor 3 that rotationally drives the oil pump 2 are disposed in the housing. It is unitized (integrated). The controller 4 is also incorporated in the housing. Note that the brushless motor 3 shown in FIG. 1 is a sensorless brushless motor having a three-phase winding.

  The oil pump 2 uses a trochoid curved pump here, and an inner rotor for pump (hereinafter referred to as “outer rotor”) 16 having external teeth on the inner peripheral side of a pump outer rotor (hereinafter referred to as “outer rotor”) 16 having internal teeth having a trochoidal tooth profile. (Hereinafter referred to as the inner rotor) 17 is engaged, and the outer rotor 16 and the inner rotor 17 are eccentrically disposed in the pump housing 15 so as to be rotatable.

  The inner rotor 17 is externally fitted and fixed to a portion closer to one side (the left side in FIG. 1) than the portion where the rotor 6 is formed in the rotational drive shaft 7, and rotates together with the rotational drive shaft 7. The outer rotor 16 has one more internal tooth than the outer teeth of the inner rotor 17, and is arranged so as to be rotatable in the pump housing 15 around a position eccentric with respect to the rotary drive shaft 7. Further, the inner rotor 17 rotates while the outer teeth mesh with the inner teeth of the outer rotor 16 at a part of the entire circumference, and the outer teeth are inscribed in the inner surface of the outer rotor 16 at almost all locations on the entire circumference. ing.

  Therefore, when the rotational drive shaft 7 is rotationally driven by the brushless motor 3, the volume of the gap between the outer rotor 16 and the inner rotor 17 of the oil pump 2 repeatedly expands and contracts during one rotation of the rotational drive shaft 7. A pump operation is performed to feed oil from an import (not shown) provided on the pump plate 14 leading to these gaps to the outport.

  The brushless motor 3 includes a rotating motor rotor (hereinafter referred to as “rotor”) 6 and a motor stator (hereinafter referred to as “stator”) 5 fixed to the outside of the outer peripheral surface of the rotor 6. The rotor 6 is formed by arranging, for example, a plurality of permanent magnets 8 along the circumferential direction on the outer peripheral surface of the rotary drive shaft 7. The rotation drive shaft 7 is a rotation shaft shared by the brushless motor 3 and the oil pump 2, and both ends thereof are rotatably supported by bearings 11 and 12 inside the pump housing 15 and the motor housing 13.

  In the stator 5, a plurality of unillustrated teeth facing the stator core 9 are arranged outside the outer peripheral surface of the rotor 6 through a slight air gap. A three-phase coil (winding) 10 is wound around each tooth of the stator core 9. Here, an insulator (not shown) for insulating the coil 10 from the stator core 9 is mounted from both axial ends of the stator core 9.

  The pump plate 14 and the pump housing 15 are made of a nonmagnetic material (for example, aluminum die casting). The motor housing 13 and the lid 18 are formed of a resin material (for example, a thermoplastic resin). The housing of the electric oil pump device 1 includes the pump plate 14, the pump housing 15, the motor housing 13, and the lid 18.

Further, in the electric oil pump device 1 of the present embodiment, a control board (hereinafter referred to as a board) 19 of a controller 4 for controlling the brushless motor 3 is attached to the motor housing 13. The control circuit on the substrate 19, the inverter circuit for supplying a driving current to the coils 10 of the brushless motor 3 and converts direct current into alternating current power source, based on the information of the rotational position of the A Utarota 16 controls the inverter circuit Has been implemented. On the surface of the substrate 19 opposite to the brushless motor 3, a control unit (angle calculation means) 20 made of electronic components such as a microcomputer, a coil, and a capacitor of the control circuit constituting the controller 4 is mounted.

  With the above configuration, the drive current controlled by the control unit 20 is supplied to each coil 10 of the brushless motor 3. As a result, a rotating magnetic field is generated in the coil 10, torque is generated in the permanent magnet 8, and the rotor 6 is rotationally driven. Thus, when the inner rotor 17 is driven to rotate, the outer rotor 16 is driven and rotated, and the gap between the inner teeth of the outer rotor 16 and the outer teeth of the inner rotor 17 is repeatedly expanded and reduced. Pump operation is performed to suck and discharge oil through the port.

  Next, FIG. 2 is a schematic cross-sectional view showing an angle detection portion of the rotor in FIG. 1, and FIG. 3 is a front view showing an angle detection surface of the rotor as seen from the direction of arrow A in FIG. As shown in FIGS. 2 and 3, a plurality of white linear detection objects (for example, painted or printed) are attached to the rotation surface of the rotor 6 facing the substrate 19 from the peripheral edge toward the center. (Detected body) 21 is formed at an equal angle.

  Further, as shown in FIG. 2, the substrate 19 has an optical sensor (detection means) 22 mounted on the surface facing the rotor 6. The optical sensor 22 is a reflective photosensor (for example, a photo reflector) in which two elements, an infrared light emitting element and an infrared light receiving element (not shown) are arranged in the same direction. Infrared light emitted from the light emitting portion of the optical sensor 22 is reflected by the detection target 21 formed on the rotating surface of the rotor 6 facing the substrate 19 and enters the light receiving portion of the optical sensor 22. Here, the optical sensor 22 identifies the presence or absence of the detection target 21 based on the difference in the amount of incident light (for example, white and black) caused by the reflectance. Then, the reflected light incident on the optical sensor 22 is converted into a pulse or analog voltage electrical signal by a control circuit unit (not shown) of the control unit 20 on the substrate 19 and taken into a microcomputer, and an estimated angle is calculated. For reference, an infrared light incident path is shown in FIG. 2 (broken arrows).

  The angle detection of the rotor 6 at the time of starting the brushless motor 3 is performed as follows. First, the rotor 6 starts rotating by energizing and starting the brushless motor 3 by forced commutation from a stopped state. Here, the controller 20 of the controller 4 estimates the angular position from the detection pattern of the detection target 21 provided on the rotation surface of the rotor 6 facing the optical sensor 22 provided on the substrate 19. For example, the brushless motor 3 of this embodiment is configured with 8 poles and 6 slots, and the mechanical period of the waveform of the cogging torque is a 15 ° period (24 peaks). Therefore, by providing the detection pattern of the detection object 21 on the surface of the rotor 6 at intervals of 15 °, the controller 4 accurately detects the angular position of the rotor 6 at the time of activation, and the estimated angle is calculated.

  In this way, the brushless motor 3 is energized by forced commutation at the time of start-up, and after the angular position is estimated, it switches to normal sensorless drive control that detects the induced voltage and estimates the angle. The actual rotational speed of the rotor 6 is detected by the detection object 21 and the optical sensor 22 even after switching to sensorless drive control. Further, parameters such as the rotation angle and rotation angular velocity of the brushless motor 3 used for internal calculation are accurately corrected by the estimated angle obtained by the measurement using the optical sensor 22, and more stable motor rotation driving is performed.

  Next, the operation and effect of the electric oil pump device 1 according to the present embodiment configured as described above will be described.

  According to the above configuration, in the electric oil pump device 1 in which the sensorless brushless motor 3 and the controller 4 are arranged adjacent to the oil pump 2, the rotor 6 of the brushless motor 3 facing the substrate 19 in the controller 4. A plurality of linear detection objects (objects to be detected) 21 are provided on the rotation surface, and an optical sensor (detection means) 22 of a reflective photosensor is disposed on a substrate 19 facing the objects. The infrared light emitted from the light emitting unit of the optical sensor 22 is reflected by the detection target object 21 and enters the light receiving unit, whereby the detection target object 21 is detected. At this time, the optical sensor 22 identifies the presence or absence of the detection target 21 based on the difference in the amount of incident light caused by the reflectance.

  When the brushless motor 3 is activated by energization by forced commutation, the detection object 21 is identified by the optical sensor 22, the angle (magnetic pole) position of the rotor 6 is detected by the control unit 20 in the controller 4, and the estimated angle Is calculated. After the estimation of the angular position, the brushless motor 3 is switched to rotation driving by normal sensor-less current control as the rotational angular velocity increases.

  As a result, the angular position of the rotor 6 can be estimated when the brushless motor 3 is started, and the rotation angle and rotation angular velocity of the rotor 6 can be calculated. Torque fluctuations due to noise can be suppressed, and abnormal noise and vibration can be prevented. In addition, it is possible to prevent step-out due to fluctuations in the rotational speed and load when the brushless motor 3 is started. As a result, the brushless motor 3 can be started smoothly and switched to sensorless drive control.

  Furthermore, since the fluctuation of the rotational angular velocity can be detected without time delay even during normal sensorless driving of the brushless motor 3, it is possible to avoid a failure of the drive circuit due to an abnormal current when an abnormality such as locking of the rotor 6 occurs.

  As described above, according to this embodiment, it is possible to provide an electric oil pump device including a brushless motor that can be smoothly started and reliably driven by sensorless control.

  Although one embodiment according to the present invention has been described above, the present invention can also be implemented in other forms.

In the above-described embodiment, an example is shown in which a photoreflector that is a reflection type photosensor is used as the optical sensor 22 and a white linear object to be detected or painted on the rotor 6 is detected as the detection target 21. However, the present invention is not limited to this, and as long as the rotor 6 and the substrate 19 face each other, a seal having a reflectance different from that of the surface of the rotor 6 may be attached. Further, another rotating body provided with a rod-like slit on the surface of the rotor 6 may be installed so that it can be optically detected.
Furthermore, the numbers of the optical sensors 22 and the detection objects 21 in the above embodiment are not limited to this, and the numbers may be increased according to the performance and computing ability of the microcomputer of the controller 4.

  In the above-described embodiment, the example in which the angular position of the rotor 6 is detected and the rotor 6 is rotated and started when the brushless motor 3 is stopped is not limited to the startup. For example, the brushless motor 3 is rotating. It is also possible to apply to the angular position estimation in the case of low speed rotation for some reason.

  In the above-described embodiment, the case where the angular position estimating means of the brushless motor 3 is applied to the electric oil pump device 1 has been described. However, the present invention is not limited to this and is applied to other devices using the same brushless motor 3. May be.

1: Electric oil pump device, 2: Oil pump, 3: Brushless motor,
4: controller, 5: stator for motor, 6: rotor for motor, 7: rotary drive shaft,
8: Permanent magnet, 9: Stator core, 10: Motor coil, 11, 12: Bearing,
13: motor housing, 14: pump plate, 15 pump housing,
16: outer rotor for pump, 17: inner rotor for pump, 18: lid, 19: substrate
20: Control unit (angle calculation means), 21: Detection target (detected body),
22: Optical sensor (detection means)

Claims (1)

An oil pump,
A brushless motor that is provided integrally with the oil pump and rotationally drives the oil pump without a sensor;
In an electric oil pump device comprising: a controller that detects an induced voltage of the brushless motor to estimate an angular position of a rotor and drives and controls the brushless motor;
Provided on the rotating surface of the brushless motor rotor facing the substrate of the controller, a plurality of detected objects reflecting infrared light , provided on the surface of the substrate facing the detected object, the infrared A detecting means for detecting the presence or absence of the detected object by a difference in the amount of reflected light generated by the detected object; and provided on the substrate and detected by the detecting means. Angle calculating means for calculating an estimated angle of the rotor from the detection pattern of the detected object,
The electric oil pump device, wherein the controller drives and controls the brushless motor based on the estimated angle of the rotor calculated by the angle calculation means when the brushless motor is started.

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