JP2022148737A - Fluid pressure correction method of electric fluid pump - Google Patents

Abstract

To provide a fluid pressure correction method of an electric fluid pump which can correct a fluid pressure based on a fluid temperature without using a temperature sensor which directly detects the fluid temperature.SOLUTION: An electric fluid pump includes: a pump part 2 which transports a fluid; a motor part 3 which drives the pump part 2; a substrate 4 formed with a control circuit which controls the motor part 3; and a housing 5 including a pump housing part 53 which houses the pump part 2, a motor housing part 54 which houses the motor part 3, and a substrate housing part 55 which houses the substrate 4. A fluid pressure correction method of the electric fluid pump includes: estimating a fluid pressure based on a driving current and a rotation speed of the motor part 3; estimating a fluid temperature from a temperature detected by a temperature sensor provided on the substrate 4; and correcting the fluid pressure based on the estimated fluid temperature.SELECTED DRAWING: Figure 1

Description

The present invention relates to a fluid pressure correction method for an electric fluid pump.

2. Description of the Related Art As an electric fluid pump mounted on a vehicle, for example, in a vehicle equipped with an idling stop mechanism (a mechanism for automatically stopping the engine when the vehicle is stopped), an electric oil pump that maintains hydraulic pressure in the transmission while the vehicle is stopped is known.

In general, the higher the temperature of the oil, the higher the viscosity of the oil. Therefore, in electric oil pumps, when the viscosity of the oil is high, the output of the motor is increased so that the required hydraulic pressure can be obtained. . In addition, in order to maintain the hydraulic pressure at a required value, the following patent document 1 estimates the hydraulic pressure based on the drive current and rotation speed of the motor, and calculates a current command value for controlling the motor based on the estimated hydraulic pressure. A method for setting the is proposed. Furthermore, in this method, the oil temperature is detected by a temperature sensor, and the current command value is corrected based on the detected oil temperature.

Japanese Patent No. 5891787

By correcting the current command value for hydraulic pressure control based on the detected oil temperature, as in the method described in Patent Document 1, it is possible to accurately control the hydraulic pressure. However, if a temperature sensor that directly detects the oil temperature is installed for that purpose, the cost of the temperature sensor is required separately, and there is a problem that structural restrictions or design changes are forced due to the installation of the temperature sensor.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a fluid pressure correction method capable of correcting the fluid pressure based on the fluid temperature without using a temperature sensor for directly detecting the fluid temperature in an electric fluid pump such as an oil pump. do.

In order to solve the above-described problems, the present invention provides a pump section for conveying a fluid, a motor section for driving the pump section, a substrate on which a control circuit for controlling the motor section is formed, and a pump housing section for housing the pump section. , a motor accommodating portion for accommodating a motor portion, and a housing provided with a substrate accommodating portion for accommodating a substrate, the fluid pressure correcting method for an electric fluid pump based on the drive current and rotation speed of the motor portion. It is characterized by estimating the fluid pressure, estimating the fluid temperature from the temperature detected by the temperature sensor provided on the substrate, and correcting the fluid pressure based on the estimated fluid temperature.

Thus, in the present invention, the fluid temperature is estimated from the temperature detected by the temperature sensor provided on the substrate, so a temperature sensor for directly detecting the fluid temperature is not required.

As the temperature sensor used in the present invention, it is preferable to use a temperature sensor that detects the temperature of electronic components provided on the substrate. In that case, there is no need to separately provide a dedicated temperature sensor for estimating the fluid temperature, so manufacturing costs can be reduced. Moreover, since it is not necessary to secure a space for installing a new temperature sensor, it is possible to avoid a large structural design change.

Moreover, it is preferable that the pump accommodating portion, the motor accommodating portion, and the board accommodating portion are integrally formed of a metal material. Since these accommodating portions are integrally formed of a metal material, the heat of the fluid is well transmitted to the substrate via the pump accommodating portion, the motor accommodating portion, and the substrate accommodating portion. Therefore, the temperature of the substrate can easily follow changes in the temperature of the fluid, and the temperature of the fluid can be estimated with higher accuracy based on the temperature detected by the temperature sensor provided on the substrate.

Also, the substrate preferably contacts the housing via the metal foil on the substrate. In this case, since the substrate and the housing are in contact with each other through the metal foil, thermal conductivity from the housing to the substrate is improved. This makes it easier for the temperature of the substrate to follow the temperature change of the fluid, thereby improving the estimation accuracy of the fluid temperature.

Also, the substrate is preferably fixed to the housing by a metal fixture. Also in this case, since the heat conductivity from the housing to the substrate is improved, the temperature of the substrate can easily follow the temperature change of the fluid, and the estimation accuracy of the fluid temperature is improved.

Moreover, it is preferable that the substrate and the housing come into contact with each other on the surface of the substrate on the side of the pump accommodating portion. As a result, the heat transfer path from the pump accommodating portion to the substrate is shortened, so that the heat of the fluid can be more easily transferred to the substrate.

Further, when the housing has a plurality of substrate mounting portions for mounting substrates, it is preferable that some of the plurality of substrate mounting portions be arranged closer to the pump accommodation portion than other substrate mounting portions. . In this case, the heat transfer path passing through the substrate mounting portion on the side of the pump accommodating portion is particularly shortened, so that the heat of the fluid is easily transferred to the substrate.

According to the present invention, the fluid pressure can be corrected based on the fluid temperature without using a temperature sensor that directly detects the fluid temperature.

1 is an axial sectional view of an electric oil pump according to one embodiment of the present invention; FIG. FIG. 2 is a sectional view showing a II-II section in FIG. 1; FIG. 2 is a sectional view showing the III-III section in FIG. 1; 3 is a plan view of the substrate viewed from the mounting surface side; FIG. 1 is a perspective view of an electric oil pump according to this embodiment; FIG. FIG. 4 is a cross-sectional view showing a substrate mounting structure; 5 is a graph showing changes in oil temperature and changes in detected temperatures of a thermistor and a CPU temperature sensor provided on a substrate; 4 is a flow chart showing a hydraulic pressure correction method according to the present embodiment; FIG. 2 is a sectional view showing an enlarged part of FIG. 1; It is the side view which looked at the board|substrate from the axial direction of the motor part.

An embodiment of the present invention will be described below with reference to FIGS. 1 to 10. FIG.

The electric oil pump of this embodiment supplies hydraulic pressure to the transmission while the engine is stopped. Oil is sucked from the oil reservoir at the bottom of the transmission case, and the oil is discharged and pumped into the transmission to ensure the necessary oil pressure in the transmission.

As shown in FIGS. 1 to 3, the electric oil pump 1 of the present embodiment includes a pump portion 2 that generates hydraulic pressure, a motor portion 3 that drives the pump portion 2, a substrate 4, the pump portion 2, and a motor portion. 3 and a housing 5 containing the substrate 4 . Each member or element will be described in detail below.

In the following description, the direction parallel to the axis O of the motor portion 3 is called the "axial direction", and the radial direction of a circle centered on the axis O is called the "radial direction" ("inner diameter direction" and "Outer diameter" also means the inner diameter and outer diameter of the circle). Also, the circumferential direction of a circle centered on the axis O is called the “circumferential direction”.

As shown in FIGS. 1 and 2, the pump section 2 of this embodiment accommodates an inner rotor 21 having a plurality of external teeth, an outer rotor 22 having a plurality of internal teeth, and an inner rotor 21 and an outer rotor 22. It is a trocolloid pump having a pump case 23 as a stationary member. The inner rotor 21 is arranged on the inner diameter side of the outer rotor 22 . The outer rotor 22 is located eccentrically with respect to the inner rotor 21 . Some of the teeth of the outer rotor 22 mesh with some of the teeth of the inner rotor 21 . If the number of teeth of the inner rotor 21 is n, the number of teeth of the outer rotor 22 is (n+1).

Both the outer peripheral surface of the outer rotor 22 and the inner peripheral surface of the pump case 23 are cylindrical surfaces that can be fitted to each other. The outer rotor 22 is rotatably arranged on the inner circumference of the pump case 23 so as to be driven to rotate with the rotation of the inner rotor 21 .

As shown in FIG. 1, the motor section 3 is arranged side by side with the pump section 2 in the axial direction. A three-phase brushless DC motor, for example, is used as the motor unit 3 . As shown in FIGS. 1 and 3, the motor section 3 includes a stator 30 having a plurality of coils 30a, a rotor 31 arranged inside the stator 30 with a gap, and an output shaft 32 coupled to the rotor 31. have. The stator 30 is formed with coils 30a corresponding to three phases of U-phase, V-phase and W-phase.

The output shaft 32 protrudes from both sides of the stator 30 in the axial direction. Portions of the output shaft 32 protruding from the stator 30 to both sides in the axial direction are rotatably supported with respect to the housing 5 via bearings (for example, rolling bearings such as deep groove ball bearings) 33 and 34 , respectively.

The inner rotor 21 of the pump section 2 is attached to the end of the output shaft 32 on the pump section 2 side. No speed reducer is arranged between the output shaft 32 and the pump section 2 , and the inner rotor 21 is directly connected to the output shaft 32 of the motor section 3 . A seal 35 having a seal lip in sliding contact with the outer peripheral surface of the output shaft 32 is arranged between the bearing 33 located on the axial pump portion 2 side and the inner rotor 21 . This seal 35 prevents oil from leaking from the pump section 2 to the motor section 3 . An axially compressed elastic member 36 is arranged between the bearing 33 and the seal 35 on the axial pump portion 2 side.

A rotation angle detector 37 is provided between the rotating side and the stationary side of the motor section 3 to detect the rotation angle of the rotor 31 in the motor section 3 . As shown in FIG. 1, the rotation angle detection unit 37 of the present embodiment includes a sensor magnet 37a (for example, a neodymium bond magnet) attached via a bracket 38 to the shaft end of the output shaft 32 on the side opposite to the pump unit, and a stationary magnet. It can be configured with a magnetic sensor 37b such as an MR element provided in the housing 5 on the side. The magnetic sensor 37 b is attached to a sub-board 39 that faces the shaft end of the output shaft 32 opposite to the pump and that is arranged in a direction perpendicular to the output shaft 32 . A detected value of the magnetic sensor 37b is input to a control circuit of the substrate 4 (main substrate), which will be described later.

A Hall element can also be used as the magnetic sensor 37b. In addition to the magnetic sensor, an optical encoder, resolver, or the like can also be used as the rotation angle detection unit 37 . It should be noted that the motor section 3 can also be driven sensorless.

As shown in FIG. 4, the substrate 4 is formed in a rectangular shape in plan view. As shown in FIGS. 1 and 3, the substrate 4 is arranged parallel to the output shaft 32 of the motor unit 3, and the mounting surface 40 of the substrate 4 extends in the tangential direction of a circle centered on the axis O of the motor unit 3. (see FIG. 10). Both ends of the substrate 4 in the tangential direction are located at positions protruding in the tangential direction from the outer peripheral contour M of the motor portion 3 (the outer peripheral contour of the stator).

A plurality of electronic components 41 are mounted on one surface of the substrate 4 . As shown in FIG. 4, the electronic parts include a capacitor (an electrolytic capacitor such as an aluminum electrolytic capacitor) 41a, a CPU 41b, a semiconductor element (inverter) 41c such as a MOS-FET, and an integrated circuit such as a driver IC, and a resistor. Utensils are used. As shown in FIGS. 2 and 3, the substrate 4 is arranged with a surface (mounting surface) 40 on which these electronic components 41 are mounted facing the pump section 2 and the motor section 3 .

Power is supplied to the substrate 4 from an external power supply through the connector 42 . The control circuit on the substrate 4 controls the polarity of the drive current. The controlled current is supplied to each coil 30a provided in the stator 30 of the motor section 3 via the busbar 43 connected to the substrate 4, as shown in FIG. A heat dissipation sheet 44 as a heat dissipation member is attached to a surface 45 of the substrate 4 opposite to the mounting surface 40 . The heat dissipation sheet 44 is made of a highly thermally conductive and compressible material. The heat-dissipating sheet 44 is arranged so as to be in contact with a high-heat-generating component (for example, the semiconductor element 41c) among the electronic components.

The housing 5 includes a cylindrical housing body 50 with both ends open, a first lid portion 51 that closes the opening of the housing body 50 on the side of the pump in the axial direction, and an opening of the housing body 50 on the side opposite to the pump in the axial direction. and a second lid portion 52 that closes. The first lid portion 51 and the second lid portion 52 are fixed to the housing body 50 using a plurality of fastening bolts B1 and B2, respectively.

The second lid portion 52 has a cylindrical bearing case 52a that supports the bearing 34 on the anti-pump portion side, and a cover 52b that closes the anti-pump portion side opening of the bearing case 52a. A sub-board 39 is arranged on the inner diameter side of the bearing case 52a. The cover 52b is attached to the bearing case 52a using a fastening member (not shown).

The housing main body 50 integrally includes a pump accommodating portion 53 that accommodates the pump portion 2, a motor accommodating portion 54 that accommodates the motor portion 3, and a substrate accommodating portion 55 that accommodates the substrate 4 in the form of a single component. The housing main body 50, the first lid portion 51, and the second lid portion 52 are made of a metal material that is a conductor and has good thermal conductivity, such as an aluminum alloy.

The pump accommodating portion 53 of the housing 5 has a substantially cylindrical shape including the pump case 23 of the pump portion 2 . A partition wall 56 is provided on the inner peripheral surface of the pump accommodating portion 53 to partition the inside of the housing into the pump portion 2 side and the motor portion 3 side. The inner peripheral surface of the partition wall 56 extends to a position close to the outer peripheral surface of the output shaft 32 . The inner peripheral surface of the partition wall 56 and the outer peripheral surface of the output shaft 32 are in a non-contact state, thereby allowing the output shaft 32 to rotate.

The motor accommodating portion 54 is formed in a cylindrical shape. The stator 30 of the motor portion 3 is press-fitted or adhesively fixed to the cylindrical inner peripheral surface of the motor housing portion 54 (see FIG. 3). The already-described bearing 33 and seal 35 on the pump section 2 side are attached to the inner peripheral surface of the motor accommodating section 54 on the axial pump section 2 side of the motor section 3 . The bearing 33 and the seal 35 are located on the side opposite to the pump portion in the axial direction with respect to the partition wall 56 .

FIG. 5 is a perspective view when the electric oil pump 1 shown in FIG. 1 is turned upside down and viewed from the pump section 2 side and the substrate accommodating section 55 side. As shown in FIG. 5, the substrate housing portion 55 of the housing 5 has a rectangular frame shape when viewed from the radial direction, and has a peripheral wall 55a with an opening on the radially outer diameter side. The peripheral wall 55a surrounds the substrate 4 placed in the substrate accommodating portion 55. As shown in FIG. After placing the substrate 4 in the substrate housing portion 55, the opening of the substrate housing portion 55 is closed by a cover 57 as a closing portion. The cover 57 is attached to the housing body 50 using the fastening member B3. The fastening member refers to all bolts including tapping screws. In this state, the cover 57 is in contact with the heat dissipation sheet 44 shown in FIG. As a result, the heat from the electronic components 41 that reach a high temperature on the substrate 4 can be efficiently released to the cover 57 and further to the housing body 50 via the heat dissipation sheet 44 . At this time, since the heat path includes the cover 57 exposed to the outside air, a cooling effect by the outside air can also be expected.

As shown in FIG. 1 , the bottom surface 55 b of the board accommodating portion 55 is formed by the outer peripheral surface of the pump accommodating portion 53 and the outer peripheral surface of the motor accommodating portion 54 . In the bottom surface 55b, there is a step in the radial direction between the outer peripheral surface of the pump accommodating portion 53 and the outer peripheral surface of the motor accommodating portion 54, and the outer peripheral surface of the pump accommodating portion 53 is radially wider than the outer peripheral surface of the motor accommodating portion 54. , at a position close to the axis O of the motor portion 3.

As shown in FIGS. 1 and 5, flange-like mounting portions 58 and 59 for mounting the electric oil pump 1 to a mounting target (a transmission case in this embodiment) are integrally formed on both sides in the axial direction of the housing body 50. It is formed. Two fastening holes 58a are formed in the mounting portion 58 on the pump portion 2 side, and two fastening holes 59a are formed in the mounting portion 59 on the anti-pump portion side. By inserting a fastening member (not shown) into these fastening holes 58a and 59a and screwing the fastening member into the attachment target, the electric oil pump 1 is attached to the attachment target.

Around the fastening holes 58a and 59a of the mounting portions 58 and 59, flat mounting surfaces 58b and 59b (see FIG. 5) that come into contact with the object to be mounted are formed. The mounting surfaces 58 b and 59 b are arranged on a common plane extending in a direction orthogonal to the substrate 4 accommodated in the substrate accommodation portion 55 .

As shown in FIG. 1 , the housing body 50 is provided with an oil flow path 6 connected to the pump portion 2 . As the oil flow path 6, a suction side oil flow path 60 and a discharge side oil flow path 61 are provided separately from each other.

As shown in FIG. 2, the suction-side oil flow path 60 includes a suction-side space 60a that opens to the meshing portion of the inner rotor 21 and the outer rotor 22, a suction hole 60b that opens to the surface of the housing body 50, and a suction-side space 60a. It has a suction side communication passage 60c that communicates between the suction holes 60b. Similarly, the discharge-side oil flow path 61 includes a discharge-side space 61a that opens to the meshing portion of the inner rotor 21 and the outer rotor 22, a discharge hole 61b that opens to the surface of the housing body 50, and the discharge-side space 61a and the discharge hole 61b. It has a discharge-side communication passage 61c communicating therewith.

Both the suction side space 60a and the discharge side space 61a are provided in the region of the pump accommodating portion 53 on the side opposite to the pump portion in the axial direction of the pump portion 2 . The suction side space 60a and the discharge side space 61a both form an arcuate shape extending in the circumferential direction of the output shaft 32 and are provided at positions opposed to each other by 180° in the circumferential direction. In this embodiment, the suction side space 60a is arranged closer to the substrate 4 than the discharge side space 61a. 5, the suction hole 60b and the discharge hole 61b are opened in the surface of the housing 5 facing the mounting target. The suction hole 60b and the discharge hole 61b are located on a plane including the mounting surfaces 58b and 59b of the mounting portions 58 and 59. As shown in FIG. As a result, there is no need to route an oil pipe around the electric oil pump 1, and the peripheral structure of the electric oil pump 1 can be simplified.

In the electric oil pump having the above configuration, the inner rotor 21 rotates by driving the motor portion 3 . As the inner rotor 21 rotates, the outer rotor 22 meshing with it is driven to rotate, and the space formed between the teeth of the two expands and contracts along with the rotation. Therefore, the oil accumulated in the oil sump inside the transmission case is sucked into the pump portion 2 through the suction side oil flow path 60 and discharged into the transmission through the discharge side oil flow path 61 .

The electric oil pump according to this embodiment having the above configuration has the following features.

As described above, in the electric oil pump according to the present embodiment, the housing 5 (housing body 50) including the pump accommodating portion 53, the motor accommodating portion 54, and the substrate accommodating portion 55 is made of aluminum having good thermal conductivity. Since they are integrally formed of an alloy, the heat of the oil flowing through the pump portion 2 and the oil flow path 6 is well transmitted to the substrate 4 via the pump housing portion 53, the motor housing portion 54, and the substrate housing portion 55. . A portion of the heat transfer path is indicated by arrows H in FIG.

Further, in this embodiment, as shown in FIG. 6, the substrate 4 is provided with a metal foil (copper foil) 62 forming a circuit pattern on the convex substrate attachment portion 50a provided on the housing body 50. , and are fixed by metal fixtures (screws) 63, the heat of the oil is transferred from the housing 5 to the substrate 4 via these metal members (metal foil 62 and fixtures 63). Well communicated. Therefore, the temperature of the substrate 4 changes in accordance with changes in the oil temperature.

Here, in the electric oil pump according to the present embodiment, a thermistor 46 and a CPU temperature sensor 47 are provided as temperature sensors for detecting the temperature of the electronic components on the substrate 4 for the purpose of failure prevention or function maintenance. there is The thermistor 46 is provided to detect the temperature of the semiconductor element (inverter) 41c, which is an electronic component on the substrate 4 that generates a particularly high amount of heat. A CPU temperature sensor 47 is a temperature sensor incorporated in the CPU 41b to detect the temperature of the CPU 41b. As described above, when the temperature of the substrate 4 changes following the change in the oil temperature, the temperatures detected by the thermistor 46 and the CPU temperature sensor 47 also change.

FIG. 7 is a graph showing changes in oil temperature and changes in the temperature detected by the thermistor 46 and the CPU temperature sensor 47 provided on the substrate 4 . In FIG. 7, To is the oil temperature, T1 is the detected temperature of the thermistor 46, and T2 is the detected temperature of the CPU temperature sensor 47. In FIG.

As shown in FIG. 7, in this embodiment, when the oil temperature To changes, the detected temperatures T1 and T2 of the thermistor 46 and the CPU temperature sensor 47 also change accordingly.

As described above, in this embodiment, the temperature detected by the temperature sensor (thermistor 46 or CPU temperature sensor 47) provided on the substrate 4 changes with changes in the oil temperature. Therefore, the oil temperature can be estimated with high accuracy. Therefore, in this embodiment, there is no need to separately provide a temperature sensor for directly detecting the oil temperature, and the existing temperature sensor (thermistor 46 or CPU temperature sensor 47) provided on the substrate 4 can be used to detect the oil temperature. can be estimated. Therefore, the cost required for estimating the oil temperature can be reduced. Moreover, since it is not necessary to secure a space for installing a new temperature sensor, it is possible to avoid a large structural design change.

In this embodiment, as shown in FIG. 6, the substrate 4 is attached to the housing body 50 via the metal foil 62 and metal fixtures 63, so that the heat of the oil is It is well transmitted to the substrate 4 via the fixture 63 made of metal. Furthermore, in this embodiment, since the convex board mounting portion 50a provided on the housing main body 50 is in contact with the surface of the board 4 on the side of the pump housing section 3, the pump housing section 53 is attached to the board 4 from the pump housing section 53. The heat transfer path to is shortened. Therefore, the heat of the oil can be transferred to the substrate 4 satisfactorily. Further, in the present embodiment, of the four board mounting portions 50a shown in FIG. Since it is located on the housing portion 53 side (see FIG. 6), the heat transfer path via the substrate mounting portion 50a1 on the pump housing portion 53 side is particularly short. As described above, in the present embodiment, since the heat transfer path from the pump accommodating portion 53 to the substrate 4 is shortened as much as possible, the oil temperature is determined based on the temperature detected by the temperature sensor provided on the substrate 4 . can be estimated accurately.

A hydraulic pressure correction method (fluid pressure correction method) according to the present embodiment will be described below.

First, as shown in FIG. 8, the hydraulic pressure is estimated based on the drive current and rotation speed of the motor section 3 (Step 1). More specifically, the drive current of the motor section 3 is detected by a current sensor (not shown), and the rotation speed of the motor section 3 is detected by the rotation angle detection section 37 (see FIG. 1) comprising a sensor magnet 37a and a magnetic sensor 37b. . In general, the hydraulic pressure increases as the drive current of the motor section 3 increases, and increases as the rotation speed of the motor section 3 decreases. can estimate the hydraulic pressure.

After calculating the hydraulic pressure (estimated hydraulic pressure Pe) from the driving current and rotation speed of the motor unit 3 as described above, the oil temperature is then estimated from the temperature detected by the thermistor 46 on the circuit board 4 or the CPU temperature sensor 47 (Step 2 ). Then, an oil temperature correction gain Kt is set based on the obtained estimated oil temperature (Step 3). Further, in this embodiment, the voltage correction gain Kv is set based on the power supply voltage of the motor section 3 (Step 4). Then, the estimated oil pressure Pe is corrected by multiplying the obtained oil temperature correction gain Kt and voltage correction gain Kv by the estimated oil pressure Pe (Step 5). Thereafter, while the electric oil pump is operating, the same procedure is repeated to correct the estimated oil pressure based on the estimated oil temperature.

As described above, in this embodiment, the oil temperature (fluid temperature) can be accurately estimated from the substrate temperature, and the estimated oil pressure is corrected based on the estimated oil temperature. can be precisely controlled. Moreover, since there is no need to use a temperature sensor for directly detecting the oil temperature, it is possible to reduce the cost and avoid a large structural design change.

Furthermore, since the present embodiment has structural features as described below, advantageous effects can be obtained in estimating the oil temperature.

As shown in FIG. 9, in the present embodiment, the bottom surface 55b of the substrate accommodating portion 55 has a step in the radial direction. , can be utilized as an arrangement space for tall components (for example, the electrolytic capacitor 41a). On the other hand, low-profile components (for example, semiconductor elements 41c, integrated circuits, or resistors) are arranged intensively in a region of the substrate 4 that faces the motor accommodating portion 54 in the radial direction.

As a result, the substrate 4 can be placed close to the bottom surface 55 b of the substrate accommodating portion 55 . Therefore, it is possible to reduce the size (thinness) of the electric oil pump 1 in the direction perpendicular to the substrate 4 , and the heat transfer path from the pump accommodating portion 53 to the substrate 4 is shortened. Good communication. In order to obtain this effect, as shown in FIG. 1, it is preferable that the outer diameter dimension d of the pump section 2 is smaller than the outer diameter dimension D of the motor section 3 (d<D). This means that while the pump section 2 is of the low capacity type, the motor section 3 is of the high speed rotation type. The required pump capacity can be ensured by rotating the low-capacity type pump unit 2 at high speed.

Furthermore, in this embodiment, as shown in FIG. 10, the substrate 4 is arranged along the tangential direction of the circle passing through the axis O of the motor unit 3, so that the electric oil is The pump 1 can be miniaturized (thin-walled). As a result, the heat transfer path from the pump accommodating portion 53 to the substrate 4 is shortened, so that the heat of the oil can be transferred to the substrate 4 satisfactorily.

As shown in FIG. 10, in the tangential direction in which the substrate 4 is arranged, both ends of the substrate 4 (right and left ends in the figure) extend to areas on both sides of the axis O of the motor section. Therefore, the end portion of the substrate 4 in the tangential direction has a greater distance from the cylindrical outer peripheral surface of the motor accommodating portion 54 than the central portion thereof. Therefore, both ends of the substrate 4 in the tangential direction can be used as spaces for arranging tall components (electrolytic capacitors 41a).

In particular, in this embodiment, as shown in FIG. 10, the center P of the substrate 4 in the tangential direction is displaced in the tangential direction with respect to the axis O of the motor section 3 (displacement width α). . Therefore, it is possible to further increase the distance to the outer peripheral surface of the motor accommodating portion 54 at one substrate end portion in the tangential direction. As a result, it is possible to reliably secure an installation space for the electrolytic capacitor 41a, which is a tall component, at one end of the substrate 4 in the tangential direction. It becomes easier to plan the conversion. As described above, in the present embodiment, the electric oil pump 1 can be made smaller in the direction perpendicular to the substrate 4, so that the heat transfer from the pump accommodating portion 53 to the substrate 4 is improved, and the oil temperature can be estimated. can be performed with higher accuracy.

The present invention is not limited to the above-described embodiments, and various modifications are possible without departing from the scope of the invention.

In the above-described embodiment, the temperature sensor for detecting the temperature of the electronic components on the board is used as the temperature sensor for estimating the oil temperature. A dedicated temperature sensor may be used. In addition, if the temperature sensor used for estimating the oil temperature is placed away from high-heat-generating components such as the semiconductor element (inverter) 41c, the temperature sensor is less susceptible to the heat of the high-heat-generating components. Accurate oil temperature estimation becomes possible.

Further, in the above-described embodiments, the case where the present invention is applied to an electric oil pump has been described as an example, but the present invention is not limited to the case where it is applied to an electric pump using oil. The present invention can also be applied to electric fluid pumps that pump out fluids other than oil, such as water pumps that pump out cooling water.

1 electric oil pump (electric fluid pump)
2 Pump Part 3 Motor Part 4 Board 5 Housing 50 Housing Body 50a Board Mounting Part 53 Pump Accommodating Part 54 Motor Accommodating Part 55 Board Accommodating Part 62 Metal Foil 63 Fixture

Claims (7)

a pump section for conveying fluid;
a motor unit that drives the pump unit;
a substrate on which a control circuit for controlling the motor unit is formed;
a housing comprising a pump accommodating portion that accommodates the pump portion, a motor accommodating portion that accommodates the motor portion, and a substrate accommodating portion that accommodates the substrate;
A fluid pressure correction method for an electric fluid pump comprising:
estimating the fluid pressure based on the drive current and rotation speed of the motor unit;
estimating the fluid temperature from the temperature detected by the temperature sensor provided on the substrate;
A fluid pressure correction method for an electric fluid pump, comprising correcting the fluid pressure based on the estimated fluid temperature. 2. The fluid pressure correcting method for an electric fluid pump according to claim 1, wherein a temperature sensor for detecting a temperature of an electronic component provided on said substrate is used as said temperature sensor. 3. The fluid pressure correcting method for an electric fluid pump according to claim 1, wherein the pump accommodating portion, the motor accommodating portion, and the substrate accommodating portion are integrally formed of a metal material. 4. The fluid pressure correction method for an electric fluid pump according to claim 1, wherein said substrate contacts said housing via a metal foil on said substrate. 5. The fluid pressure correction method for an electric fluid pump according to any one of claims 1 to 4, wherein said board is fixed to said housing by a metal fixture. 6. The fluid pressure correcting method for an electric fluid pump according to claim 1, wherein said substrate and said housing are in contact with each other on a surface of said substrate on a side of said pump accommodating portion. The housing has a plurality of board mounting portions for mounting the board,
7. The fluid of the electric fluid pump according to any one of claims 1 to 6, wherein some of the plurality of board mounting portions are arranged closer to the pump accommodating portion than other board mounting portions. Pressure compensation method.

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