JPH07259676A - Electrically driven type fuel pump - Google Patents

Abstract

PURPOSE:To effectively discharge heat in a heating part on a control circuit in a circuit case by means of fuel which flows through the inside of the housing of a motor part. CONSTITUTION:An electrically driven type fuel pump is provided with a motor part 2 comprising an electrically driven motor, a pump part which is driven by the motor part 2, and a circuit case in which a control circuit for the electrically driven motor is housed, and which is arranged in the housing 1 of the motor part 2, and fuel which is sucked in by the pump part owing to driving of the electrically driven motor is discharged outside passing the inside of the housing 1 of the motor part 2. A passage throttle part 104 which is faced to the part of the outer surface of the circuit case confronting the heating part of the control circuit, and for making fuel flow aggregately, is provided in a fuel passage in which fuel of the motor part 2 flows.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric fuel pump installed in a fuel tank of an automobile and used for supplying the fuel in the tank to an engine.

[0002]

2. Description of the Related Art A conventional electric fuel pump is disclosed in, for example, Japanese Utility Model Laid-Open No. 62-172272 proposed by the same applicant. This electric fuel pump includes a motor section including an electric motor, a pump section driven by the motor section, and a circuit case that accommodates a control circuit of the electric motor and is installed in a housing of the motor section. The fuel sucked by the pump portion by driving the electric motor is discharged to the outside through the housing of the motor portion. The circuit case accommodating the control circuit is installed in the housing of the motor part with substantially the entire circumference of the case immersed in the fuel in the fuel passage, and a fuel passage is formed so as to enclose the entire case. ing. The circuit case is entirely cooled by the fuel passing through the fuel passage, and the heat of the power element in the control circuit, which generates a large amount of heat, is released.

[0003]

SUMMARY OF THE INVENTION In the above-mentioned conventional one,
When the fuel flows so as to spread over the entire circuit case, it is difficult to intensively cool the heat generating part of the power element in the control circuit.Therefore, depending on the mounting position of the heat generating part in the circuit case, the heat dissipation effect is small. There is also. Further, as a countermeasure against this, a heat sink may be attached to the circuit case to improve heat dissipation, but this is not preferable because it causes an increase in case size and a pump size.

Therefore, the present invention has been made to solve the above-mentioned problems, and the purpose thereof is to efficiently dissipate the heat of the heat generating portion of the control circuit in the circuit case by the fuel flowing in the housing of the motor portion. An object is to provide an electric fuel pump that can be used.

[0005]

In order to achieve the above-mentioned object, the invention of claim 1 accommodates a motor section comprising an electric motor, a pump section driven by the motor section, and a control circuit for the electric motor. And a circuit case installed in the housing of the motor unit, wherein the fuel sucked by the pump unit by the drive of the electric motor is discharged to the outside through the housing of the motor unit. Is a fuel passage in which a fuel passage is provided with a passage throttle portion facing the outer surface portion of the circuit case corresponding to the heat generating portion of the control circuit and collectively flowing the fuel. The invention of claim 2 is
The electric fuel pump according to claim 1, wherein the substrate of the control circuit having the heat generating portion is in close contact with the inner surface of the circuit case.

[0006]

According to the first aspect of the present invention, the fuel intensively flows through the passage throttle portion of the fuel passage of the motor portion, so that the flow velocity of the fuel flowing through the passage throttle portion increases, and the fuel having the increased flow velocity is used. The portion of the circuit case facing the passage restriction is effectively cooled. Therefore, the heat of the heat generating portion of the control circuit located at the position corresponding to the cooling portion of the circuit case can be positively released. According to the invention of claim 2, the cooling portion of the circuit case and the heat generating portion of the control circuit are adjacent to each other with the wall of the case interposed therebetween, so that the heat of the heat generating portion of the control circuit can be quickly released.

[0007]

Embodiments Embodiments 1 and 2 of the present invention will be described in order. [Embodiment 1] Embodiment 1 will be described with reference to FIGS. First, an outline of the electric fuel pump will be described, and later, the fuel passage around the circuit case, which is a main part, will be described in detail. As shown in the longitudinal sectional view of FIG. 2, the electric fuel pump includes a motor unit 2 composed of a brushless motor incorporated in a cylindrical metal housing 1 and an impeller pump unit 3 incorporated under the motor unit 2. It consists of and. 2A is a sectional view taken along line AA of FIG. 2, FIG. 3B is a sectional view taken along line BB of FIG. 2, and FIG. 3C is a sectional view taken along line CC of FIG. In (d), a plan view of the fuel pump is shown.

In FIG. 2, the pump case of the pump portion 3 is constituted by first to fifth covers 4 to 8 which are laminated in a laminated manner. The fifth cover 8 located at the uppermost stage is fixed to the stepped portion at the lower end of the housing 1 by caulking. The other first to fourth covers 4 to 7 are fixed to the fifth cover 8 by mounting screws 9. Between the first cover 4 and the third cover 6 and between the third cover 6 and the fifth cover 8, a second
A pump chamber surrounded by the cover 5 or the fourth cover 7 is formed. Disc-shaped impellers 12 and 13 each having a large number of blade grooves on the outer circumference are rotatably arranged in each pump chamber (see FIGS. 3A and 3B). A rotor shaft 25 of a rotor 24 in a motor unit 2 described later is connected to the impellers 12 and 13 by fitting.

The first to fifth covers 4 to 8 form a substantially C-shaped pump passage corresponding to the blade grooves of the impellers 12 and 13. The lower end of the pump flow path communicates with the suction port 14 provided in the first cover 4 and the end thereof communicates with the communication port 15 provided in the third cover 6 (FIGS. 2 and 3). (See (a)). The upper end of the pump flow passage communicates with the communication port 15 and the end thereof communicates with the pump portion outlet 16 provided on the fifth cover 8 (see FIG. 3B). The pump section outlet 16 communicates with a motor chamber of the motor section 2 described later.

In the motor section 2 for driving the pump section 3 shown in FIG. 2, a pair of upper and lower holders 19 and 18 for supporting a circuit case 47 are provided at the upper end of the housing 1.
Is fitted and the upper cover 22 is fitted, and both holders 18 and 19 and the upper cover 22 are fixed by caulking the ends. The lower holder 18 is locked at the upper step of the housing 1. A motor chamber is formed between the lower holder 18 in the housing 1 and the fifth cover 8. In addition to the pair of holders 18 and 19, this fuel pump has an auxiliary 3
Since individual holders 17, 20 and 21 are used, the first to fifth parts are attached in front of the holders to distinguish the holders 17 to 21, and the upper holder 19 is the third holder, The lower holder 18 is called the second holder, the holder 17 is the first holder, the holder 20 is the fourth holder,
The holder 21 is called a fifth holder.

The rotor 24 arranged in the motor chamber is
As shown in FIG. 3C, the rotor magnet 27 is attached to the rotor shaft 25 via the collar 26,
A rotor cover 28 made of a magnetic material is attached to both end surfaces of the collar 26 and the rotor magnet 27 as shown in FIG. The upper internal structure of the fuel pump is shown in detail in FIG. 1 in a vertical sectional view. As shown in FIGS. 1 and 2, the upper and lower ends of the rotor shaft 25 are rotatably supported by the second holder 18 and the fifth cover 8 via bearings 29 and 30, respectively. The lower end portion of the rotor shaft 25 extends to the pump portion 3 and is connected to the impellers 12 and 13 by fitting (see FIGS. 3A and 3B).

Further, as shown in FIG. 1, the upper end of the rotor shaft 25 extends between the pair of upper and lower holders 19 and 18, and the end has a substantially disc shape and the rotor is provided on the upper surface thereof. A substantially disk-shaped magnet case 32, which is formed by annularly arranging a magnetized sensor magnet 31 similar to the magnet 27, is screwed. A sectional view taken along the line DD of FIG. 1 is shown in FIG.

As shown in FIG. 2, a stator 34 corresponding to the rotor magnet 27 of the rotor 24 is provided on the inner peripheral surface of the housing 1 in the motor chamber. In the stator 34, as shown in FIG. 3C, a stator coil 36 is wound in three phases in a winding groove 37 of a core 35 in which a large number of stator plates are laminated. The space inside the winding groove 37 around which the stator coil 36 of the core 35 is wound serves as a fuel passage for the fuel flowing through the motor chamber.

In FIG. 2, a positive side terminal 39 and a negative side terminal 40 for connecting a power source to the stator coil 36 are attached to the upper cover 22, and communicate with, for example, a fuel injection valve of an automobile engine. A discharge port 41 for connecting a fuel supply pipe (not shown) is provided (see FIG. 3D). As shown in FIG. 1, each of the terminals 39 and 40 is inserted into the mounting hole from the lower surface of the upper cover 22 via a spacer and is fixed to the tip of the terminal with a nut via a washer. The discharge port 4
A check valve 45 for preventing the reverse flow of fuel is installed in the apparatus 1 in a state of being biased by a spring 46 in a closing direction (downward in the drawing).

The second holder 18 and the third holder 19
Between the circuit case 47 and the flange 48 on the outer periphery thereof.
It is supported in a state where it is sandwiched. As will be described later in detail, the circuit case 47 accommodates the control circuit of the brushless motor, and a fuel passage that connects the motor chamber and the discharge port 41 is provided around the control circuit.

In the electric fuel pump, the impellers 12 and 13 of the pump portion 3 are rotated by driving the motor portion 2 using a battery (not shown) of an automobile or the like as a power source. As a result, the fuel in the fuel tank is pumped up from the suction port 14 of the first cover 4 to the lower pump flow path. The pumped fuel is pressurized by the rotation of the impellers 12 and 13 while flowing through the pump passage and the upper pump passage, is discharged from the pump portion outlet 16 of the fifth cover 8, and passes through the motor chamber. Then, the fuel is discharged from the discharge port 41 of the upper cover 22 through the fuel passage around the circuit case 47.

The rotor 2 is accommodated in the circuit case 47.
A control circuit 50 shown in the circuit diagram of FIG. 9 for switching the excitation phase in association with the angle of 4 is accommodated. Figure 9
In the figure, reference numeral 51 is an overvoltage protection circuit, 52 is a constant voltage power supply circuit, and 53 is three Hall elements as position detection sensors for detecting the angle of the rotor 24. Also,
Reference numeral 54 is a power transistor, which is connected to each stator coil 36. 55 is a three-phase logic circuit, and 56 is an overcurrent protection circuit. This control circuit 5
At 0, the rotor 24 rotates and the sensor magnet 31 rotates. 3 placed facing this sensor magnet
Each Hall element 53 outputs a signal corresponding to the magnetic flux of the sensor magnet 31, the three-phase logic circuit 55 determines the excitation phase based on this signal, and the power transistor 54 switches the excitation phase of the stator coil 36. The rotor 24 is rotated at full rotation.

A circuit case 47 accommodating the control circuit 50 is shown in an explanatory view in FIG. The circuit case 47 is shown in FIG.
As shown in a partially cutaway front view in (a), an outer peripheral flange 48 of a stem 58 on the upper side of the drawing and a cap 59 on the lower side of the same is liquid-tightly joined by full circumference welding or the like. In the circuit case 47, a control unit substrate 61 supported by an intermediate portion via a resin holder 60 and a power unit substrate 62 closely attached to the inner surface of the stem 58 are accommodated. Each board 61,
In the element 62, the lower surface side of FIG. 8A is the element mounting surface. Further, two external power supply connecting terminals 63 and three connecting terminals 64 for connecting the stator coil 36 are attached to the stem 58 via hermetic seals. Each terminal 63, 64
Are arranged in parallel as shown in the explanatory view of the assembly part of the holder in FIG.

On the control section substrate 61, three Hall elements 53 are mounted in a predetermined positional relationship as shown in FIG. Hall element 53
Detects the rotating magnetic field of the sensor magnet 31.
Further, on the power unit substrate 62, three power transistors 54, a current detecting resistor 66, etc. are mounted as shown in the element mounting surface of FIG. 8B. The power transistor 54 has a large amount of heat generation, and it is necessary to release the heat. The three power transistors 54 are arranged in parallel between the columns of the terminals 63 and 64.

A fuel passage described in detail below is provided around the circuit case 47. The fuel passage around the case is shown in Fig. 1.
Also, as shown in FIG. 2, the circuit case 47, the housing 1, and the first to fifth holders 17 to 21 are formed. The fuel passage will be described below while explaining each of the holders 17 to 21. For convenience of description, the second holder 18, the first holder 17, the fourth holder 2
0, the fifth holder 21, and the third holder 19 will be described in this order.

The second holder 18 will be described with reference to FIGS. 6 and 4A showing plan views thereof. The second holder 18 has a bearing hole 69 in which the bearing 29 of the rotor shaft 25 is attached to the axial center portion of the disc-shaped main plate 68.
Is provided. Further, on the outer peripheral portion of the upper surface of the main plate 68, four side pieces 70 having steps at which the flanges 48 of the circuit case 47 are fitted are protruded at substantially equal intervals. Further, two passage holes 71 that form the fuel passage are formed between the adjacent side pieces 70 at the line symmetrical positions. Between the other side pieces 70, one small hole 72 and three small holes 73 through which the ends of the stator coil 36 are inserted are provided. In addition, on the lower surface of the main plate 68, as shown in FIG.
An annular flange ring 74 is formed, as shown in FIG. 3, and a retainer 75 fitted in the flange ring 74.
The bearing 29 is fixed by.

The first holder 17 will be described with reference to FIG. 7, which is a plan view thereof. The first holder 17 has the second holder 18 at the axial center portion of the disc-shaped main plate 77.
Is provided with a fitting hole 78 that fits into the flange ring 74 of the cylindrical portion 7 that fits into the small holes 72 and 73.
It has 9,80. A flange ring 81 is formed on the outer peripheral portion of the lower surface of the main plate 77 so as to contact the end surface of the stator 34. Further, each passage groove 82 is formed in a symmetrical shape so as to be continuous with the fitting hole 78 and open to the position of each passage hole 71 of the second holder 18 in a substantially U-shape.

The fourth holder 20 will be described with reference to FIG. 5 (a) showing a plan view of the assembly part of the holder. The fourth holder 20 has a flat plate portion 85 facing the upper surface of the circuit case 47 and having a fitting hole 84 into which the two external power supply connecting terminals 63 can be fitted, and a substantially semi-circular plate-shaped flat plate portion 85. It is provided with a side piece portion 86 protruding downward from the outer peripheral portion in an L-shape and engaged between adjacent side pieces 70 with one small hole 72 of the second holder 18 interposed therebetween. (See FIG. 4 (a)). The side piece portion 86 is provided with an insertion hole 87 through which the end of the stator coil 36 is inserted.

The fifth holder 21 will be described with reference to FIG. The fifth holder 21 has substantially the same shape as the fourth holder 20, and has a fitting hole 89 which faces the upper surface of the circuit case 47 and into which the three connecting terminals 64 can be fitted. A substantially semi-circular plate-shaped flat plate portion 9 having
0, and a side piece portion 91 protruding downward from the outer peripheral portion thereof in an L shape and engaged between adjacent side pieces 70 with the three small holes 73 of the second holder 18 interposed therebetween. (See FIG. 4A). The side piece 91 is provided with an insertion hole 92 through which the end of the stator coil 36 is inserted.
A space is provided between the facing surfaces of the flat plate portion 90 of the main holder 21 and the flat plate portion 85 of the fourth holder 20.

Regarding the third holder 19, FIG. 5 (b) showing a plan view of the assembly portion of the holder, and E in FIG.
It will be described with reference to FIG. The third holder 19 includes the fourth and fifth holders 20 and 21.
A fuel passage hole 95 is formed in an axial center portion of a disk-shaped main plate 94 facing upward. A side piece 96, which is assembled in abutment with each side piece 70 of the second holder 18 and presses the flange 48 of the circuit case 47 at its tip, projects from the outer periphery of the lower surface of the main plate 94. .

The main plate 94 is formed with opening holes 97 and 98 in which the terminals 63 and 64 of the circuit case 47 protruding through the fourth and fifth holders 20 and 21 are located. On the upper surface of the main plate 94, as shown in FIG. 5B, there is formed a fitting recess 99 into which the base end portions (lower end portions) of the + side terminal 39 and the − side terminal 40 for power supply connection are fitted. And a lead wire 10 for connecting the terminals 39, 40 to the terminals 63, 64 of the circuit case 47.
A concave portion 102 for accommodating 0 and 101 is formed. The recess 102 and the opening 97.98 are formed by resin molding (reference numeral 1) as shown in FIG.
(Marked with 03).

The fuel passage formed in the space surrounded by the third to fifth holders 19 to 21 and a part of the circuit case 47 has a space between the fourth and fifth holders 20 and 21. It is a passage throttle portion (denoted by reference numeral 104) that is concentrated by the flow of fuel (see FIGS. 1 and 5).
(See (a)). The passage restrictor 104 is provided in the circuit case 4
7 faces the heat generating portion of the control circuit 50, that is, the portion of the case outer surface (corresponding to the stem outer surface) corresponding to the power transistor 54. The passage throttle portion 104 communicates with the passage hole 95 of the third holder 19. 1 and 5A, the passage throttle portion 104 is provided between the side surfaces 86 of the fourth and fifth holders 20 and 21 between the peripheral surfaces of the housing 1 and the circuit case 47. 91
Second holder 18 and third holder 19
In communication with the space between adjacent side pieces (denoted by 105 and 106).

According to the electric fuel pump described above, the fuel fed into the motor chamber by the operation of the pump portion 3 has the passage groove 82 of the first holder 17, the passage hole 71 of the second holder 18 and the space from the motor chamber. After passing through the portions 104 and 105 and the passage throttle portion 104, the third holder 19
The liquid is discharged from the discharge port 41 of the upper cover 22 through the passage hole 95. Note that the flow of fuel is indicated by arrows in FIG. At this time, since the fuel intensively flows in the passage throttle portion 104 in the fuel passage of the motor unit 2, the flow velocity of the fuel flowing in the passage throttle portion 104 increases, and the fuel having the increased flow velocity causes the passage throttle portion 104 to face the passage throttle portion 104. The portion of the circuit case 47 that has been cooled is effectively cooled. Therefore, the heat of the heat generating portion of the control circuit 50, that is, the power transistor 54 located at the position corresponding to the cooling portion of the circuit case 47 can be positively released.

Further, since the power unit substrate 62 of the control circuit 50 having the heat generating portion in the circuit case 47 is in close contact with the inner surface of the stem 58 of the circuit case 47, the circuit case 47.
Of the control circuit 50 and the heat generating portion of the control circuit 50 are adjacent to each other with the stem 58, which is the case wall, in between.
The heat of the exothermic part can be quickly released.

[Second Embodiment] A second embodiment will be described with reference to FIGS. This example is an example in which a DC motor is incorporated in the motor unit 2 instead of the brushless motor of the first embodiment. FIG. 11 shows a vertical sectional view of the same, and FIG. 10 shows an enlarged sectional view of an essential part thereof. 12A is a plan view of the fuel pump, and FIG. 12B is a sectional view taken along line BB of FIG. It should be noted that the pump part 3 has some differences in assembly, but since it has the same function as an impeller type pump, parts that are considered to have an equivalent configuration are given the same reference numerals, and description thereof will be omitted.

In the motor section 2 composed of a DC motor,
An upper cover 108 is attached to the upper end of the housing 1, and a motor chamber is formed between the upper cover 108 and the fifth cover 8 in the housing 1. An armature 110 is arranged in the motor chamber, and upper and lower ends of a shaft 111 of the armature 110 are rotatably supported by the covers 108 and 8 via bearings 112 and 30, respectively. A pair of magnets 113 are fixed to the inner peripheral surface of the housing 1.

The upper cover 108 is in sliding contact with the commutator 114 of the armature 110 as shown in FIG. 12 (b).
The pair of brushes 115 shown in FIG. Further, the upper cover 108 has a structure shown in FIG. 10 and FIG.
As shown in FIG. 2, the external power supply connector 116 and the connector terminal 117 are provided, and
A discharge port 118 that communicates the motor chamber and the outside is provided. A check valve 45 for preventing a backflow of fuel is incorporated in the discharge port 118 in a state of being biased in a closing direction by a spring 46. A relief valve 120 is incorporated in the upper cover 108.

In the electric fuel pump, the pump portion 3 is operated by driving the motor portion 2 so that the fuel passing through the motor chamber is discharged through the discharge port 11 of the upper cover 108.
8 is discharged. Discharge port 1 of the upper cover 108
In FIG. 18, a circuit case 121 described in detail below is installed via a holder 122 in a portion communicating with the motor chamber.

The circuit case 121 contains a control circuit 123 for controlling the rotation speed of the DC motor, which is shown in the circuit diagram of FIG. In FIG. 15, reference numeral 124 is a power diode, and 125 is a power transistor IC. The power transistor IC125 is
Constant voltage power supply circuit with noise filter, triangular wave oscillator that outputs triangular wave, ECU (engine control unit)
Control unit circuit 126 including a DUTY / V converter for converting a signal indicating the required fuel amount of the engine sent from the converter into a voltage, a comparator for comparing the triangular wave by the triangular wave oscillator and the voltage converted by the DUTY / V converter, and a power The transistor 127 is integrated into one chip. The power diode 124 is provided to protect the power transistor 127. The duty ratio of the electric motor is controlled by the control circuit 123. While the engine requires a large amount of fuel, the power transistor 127 is turned on for a long time to rotate at high speed. The off time of the transistor 127 becomes longer and the transistor 127 rotates at a low speed.

A circuit case 121 accommodating the control circuit 123 is shown in an explanatory view in FIG. Circuit case 1
It is housed in 21. 14A is a partially cutaway plan view, FIG. 14B is a sectional view taken along line DD of FIG. 14A, and FIG. 14C is a sectional view taken along line EE of FIG. The circuit case 121 is
An outer peripheral flange of the stem 129 on the upper side of the drawing and a cap 130 on the lower side of the same is liquid-tightly joined by full circumference welding or the like. In the circuit case 121, the power unit substrate 131 that is in close contact with the inner surface of the stem 129 is housed. Terminals 132 for external power supply connection and brush connection are attached to the stem 129 via hermetic seals.

The upper surface of the power part substrate 131 is an element mounting surface, and the power diode 124 and the power transistor IC 125 are mounted on the element mounting surface. The power diode 124 and the power transistor IC 125 generate a large amount of heat, and it is necessary to release the heat.

The circuit case 121 is attached to the upper cover 10
The holder 122 for attachment to the No. 8 is formed on the circuit case 121 by resin molding as shown in the explanatory view of FIG. 13A is a front view of the holder-equipped circuit case, FIG. 13B is a side view of the same, and FIG. 13C is a side sectional view. The holder 122 has the circuit case 1 in a state where the lead wire 135 for connecting the connector terminal and the lead wire 136 of the brush 115 are connected to each terminal 132.
21 together with the lead wires 135 and 136 are resin-molded into a substantially U-shape. The holder 122 includes the power diode 124 and the power transistor IC.
It is formed in the remaining stem half (right half in the figure) with the mounting side stem half (the left half in FIG. 13B) of 125 exposed.

As shown in FIGS. 10 and 12B, the circuit case with holder 121 has the upper cover 10 as shown in FIG.
It is installed by fitting the holder 122 into the recess 137 of the eight. The connector terminal connection lead wire 135 is connected to the end of the connector terminal 117 protruding from the upper cover 108 toward the motor chamber side, and the brush 115 is incorporated in the recess of the upper cover 108, which is not shown, but is a commutator of the armature 110. 1
Sliding contact with 14.

By installing the holder-equipped circuit case 121 on the upper cover 108, the fuel passage to the discharge port 118 is narrowed so that the fuel is intensively flown (reference numeral 13).
(Denoted by 8) is formed. The passage restricting portion 138 is a heat generating portion of the control circuit 123 in the circuit case 121, that is, the power diode 124 and the power transistor I.
It faces the exposed portion of the case outer surface (corresponding to the stem outer surface) corresponding to C125.

According to the electric fuel pump, the fuel fed into the motor chamber by the operation of the pump portion 3 passes through the passage throttle portion 138 from the motor chamber and is then discharged from the discharge port 118 of the upper cover 108. In FIG. 10, the flow of fuel is indicated by arrows. At this time, the fuel intensively flows through the passage throttle portion 138 in the fuel passage of the motor unit 2, so that the flow velocity of the fuel flowing through the passage throttle portion 138 increases, and the fuel having the increased flow velocity causes the passage throttle portion 138 to come into contact with the surface of the passage throttle portion 138. The portion of the circuit case 121 that has been cooled is effectively cooled. Therefore, the heat generating portion of the control circuit 50 at the position corresponding to the cooling portion of the circuit case 121, that is, the power diode 124 and the power transistor IC1.
The heat of 25 can be actively released.

Further, the power section substrate 131 of the control circuit 123 having the heat generating section in the circuit case 121 is the circuit case 1 described above.
Since it is closely attached to the inner surface of the stem 129 of the control circuit 121, the cooling portion of the circuit case 121 and the heat generating portion of the control circuit 50 are adjacent to each other with the stem 129 that is the case wall in between, and the heat of the heat generating portion of the control circuit 121 is removed. It can be released promptly.

[0042]

According to the first aspect of the present invention, the fuel is intensively caused to flow through the passage throttle portion of the fuel passage of the motor portion, and the flow velocity of the fuel is increased to cool the circuit case to a portion.
The heat of the heat generating portion of the control circuit in the circuit case can be efficiently released. According to the second aspect of the invention, the heat of the heat generating portion of the control circuit can be quickly released, and high heat dissipation can be obtained.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of an essential part showing an electric fuel pump according to a first embodiment.

FIG. 2 is a vertical cross-sectional view showing the entire pump of FIG.

FIG. 3 is a cross-sectional view of each part of FIG.

FIG. 4 is an explanatory diagram of each part in FIG.

FIG. 5 is an explanatory view of an assembly portion of a holder.

FIG. 6 is a plan view of a second holder.

FIG. 7 is a plan view of a first holder.

FIG. 8 is an explanatory diagram of a circuit case.

FIG. 9 is a circuit diagram of a control circuit.

FIG. 10 is a longitudinal sectional view of an essential part showing an electric fuel pump according to a second embodiment.

11 is a vertical cross-sectional view showing the entire pump of FIG.

12 is an explanatory diagram of each part of FIG.

FIG. 13 is an explanatory diagram of a circuit case with a holder in which the circuit case is resin-molded.

FIG. 14 is an explanatory diagram of a circuit case.

FIG. 15 is a circuit diagram of a control circuit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Housing 2 Motor part 3 Pump part 47,121 Circuit case 50,123 Control circuit 54 Power transistor 62,131 Substrate 104,138 Passage throttle part 124 Power diode 125 Power transistor IC

Claims (2)

[Claims] 1. A motor unit comprising an electric motor, a pump unit driven by the motor unit, and a circuit case that accommodates a control circuit of the electric motor and is installed in a housing of the motor unit. In an electric fuel pump that discharges fuel sucked in by a motor driven by a motor to the outside through a housing of the motor,
An electric fuel pump in which a fuel passage of the motor section through which fuel flows is provided with a passage throttle section that faces an outer surface portion of the circuit case corresponding to a heat generating section of the control circuit and that collectively flows the fuel. 2. The electric fuel pump according to claim 1, wherein the substrate of the control circuit having the heat generating portion is in close contact with the inner surface of the circuit case.