JP2005315088A - Electric pump device - Google Patents

Abstract

To prevent loosening of a terminal holder and a press-fitting portion of a terminal in an electric pump device, to improve the sealing performance of the press-fitting portion, and to avoid a decrease in pump efficiency.
A pump 3 is connected to one end of an electric motor 2 and a terminal holder 14 made of synthetic resin is connected to the other end, and a terminal mounting hole 15 provided in the terminal holder 14 is inserted into the terminal holder 14 from the inside. In the electric pump device in which the power feeding terminal 19 is press-fitted and coupled, a locking hole 30 is provided in the terminal 19, and a locking protrusion 31 that elastically engages with the locking hole 30 protrudes from the inner surface of the terminal mounting hole 15. Set up.
[Selection] Figure 7

Description

  In the present invention, a pump driven by the rotor is connected to one end of the electric motor, and a terminal holder made of synthetic resin is connected to the other end, and the terminal holder is provided in a terminal mounting hole provided in the terminal holder. The present invention relates to an improvement of an electric pump device formed by press-fitting a power feeding terminal from the inside.

Such an electric pump device is already known as disclosed in Patent Document 1 below.
JP 2003-18185 A

  In the conventional electric pump device of this type, since the terminal is coupled to the terminal holder only by press-fitting the terminal into the terminal mounting hole of the terminal holder, it is difficult to obtain a sufficient coupling strength between the two, and the long-term May cause loosening of the press-fit portion of the terminal. According to such loosening, the high-pressure fluid in the electric motor pressurized by the pump leaks outside through the terminal holder and the terminal, and the pump efficiency Will be reduced somewhat.

  The present invention has been made in view of such circumstances, and it is possible to easily and surely prevent loosening of the terminal holder and the press-fitting portion of the terminal, to improve the sealing performance of the press-fitting portion, and to avoid a decrease in pump efficiency. An object of the present invention is to provide an electric pump device that can be used.

  In order to achieve the above object, the present invention provides a terminal provided on a terminal holder by coupling a pump driven by the rotor to one end of the electric motor and a terminal holder made of synthetic resin to the other end. In the electric pump device in which the power feeding terminal is press-fitted into the mounting hole from the inside of the terminal holder, a locking hole is provided in a portion of the terminal facing the terminal mounting hole, and the locking hole is elastically formed. The first feature is that a locking projection that engages with the terminal is projected on the inner surface of the terminal mounting hole.

  The pump corresponds to the fuel pump 3 in the embodiment of the present invention described later.

  According to the present invention, in addition to the first feature, the terminal has a press-fit portion that is press-fitted and joined to the terminal attachment hole on the inlet side, and a loose fitting that loosely fits to the terminal attachment hole on the outlet side. And a wedge-shaped seal stepped portion between the press-fitting portion and the loose portion that bites into the inner surface of the terminal attachment hole, and the locking hole is provided in the loose portion. .

  Furthermore, in addition to the first or second feature, the present invention holds a bearing boss that rotatably supports one end of the rotor shaft of the rotor and a brush that is slidably in contact with the commutator of the rotor in the terminal holder. A third feature is that the cylindrical brush guide is integrally formed.

  According to the first feature of the present invention, the power feeding terminal is press-fitted into the terminal mounting hole of the terminal holder, and the locking protrusion on the inner surface of the terminal mounting hole is elastically engaged with the locking hole of the terminal. Therefore, it is possible to firmly connect to the terminal holder, thus preventing the press-fitting part from loosening for a long period of time, reliably preventing leakage of high-pressure fuel from the motor housing through the terminal mounting hole, and reducing pump efficiency. Can be prevented.

  Further, according to the second feature of the present invention, the wedge-shaped seal step of the terminal bites into the inner surface of the terminal mounting hole, thereby improving the sealing performance between the terminal and the terminal mounting hole and reliably preventing high-pressure fuel leakage. Therefore, high pump efficiency can be maintained for a long time. Further, since the loose portion of the terminal is bent in the terminal mounting hole, the engaging hole and the engaging protrusion can be easily elastically engaged, and the assembling property of the terminal can be improved.

  Furthermore, according to the third feature of the present invention, the terminal holder, the bearing boss, and the brush guide are integrally formed, so that the number of parts can be reduced and the structure can be simplified, thereby contributing to the cost reduction of the electric pump device. .

  Embodiments of the present invention will be described below on the basis of preferred embodiments of the present invention shown in the accompanying drawings.

  1 is a longitudinal sectional view (sectional view taken along line 1-1 of FIG. 2) of an electric pump device according to an embodiment of the present invention, FIG. 2 is an enlarged view of part 2 of FIG. 1, and FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. 3, FIG. 5 is an enlarged view of part 5 of FIG. 1, FIG. 6 is a cross-sectional view taken along line 6-6 of FIG.

  First, in FIG. 1, an electric pump device 1 is used, for example, in a fuel supply system of an engine of a motorcycle or an automobile, and includes an electric motor 2 and a fuel pump 3 driven thereby.

  The electric motor 2 includes a cylindrical motor housing 4 made of a magnetic metal, and a pair of field permanent magnets 5 and 5 serving as a stator are attached along the inner peripheral surface thereof. A rotor 6 is rotatably disposed inside the rotor.

  For example, a pump housing 7 of a Wesco type fuel pump 3 is coupled to the cylindrical motor housing 4 so as to close one end thereof. The pump housing 7 includes an outer housing 7a made of synthetic resin and an inner housing 7b made of synthetic resin which is opposed to the inside of the outer housing 7a and defines a circular pump chamber 8 therebetween. The outer and inner housings 7a and 7b are joined to each other by fitting them to the inner periphery of one end of the motor housing 4 so as not to rotate, and then crimping the one end to the outer surface of the outer housing 7a. At the same time, it is coupled to the motor housing 4.

  A pump impeller 10 is rotatably accommodated in the pump chamber 8, and a rotor shaft 6 a coupled to the central portion of the rotor 6 of the electric motor 2 is fitted and connected to the central portion of the pump impeller 10. The outer housing 7 a is provided with a suction port 11 that communicates with the pump chamber 8, and the inner housing 7 b is provided with a discharge port 12 that allows the pump chamber 8 to communicate with the motor housing 4. The suction port 11 communicates below the fuel oil level in the fuel tank by installing the electric pump device 1 at the bottom of the fuel tank (not shown).

  A synthetic resin terminal holder 14 is coupled to the other end of the motor housing 4 so as to close the motor housing 4. That is, the terminal holder 14 has a bottomed cylindrical shape and has a flange 14b on the outer periphery. The flange 14b is fitted to the other end of the motor housing 4, and the other end is connected to the outer surface of the flange 14b. The terminal holder 14 is coupled to the motor housing 4 by crimping to the side.

  As shown in FIGS. 1 to 3, a coupler 26 is integrally formed on the outer surface of the end wall 14 a of the terminal holder 14. It is attached to the wall 14a. Both terminals 19 and 19 and the mounting structure to these terminal holders 14 will be described in detail later.

  Further, a fuel outlet pipe 16 protruding outward is integrally formed on the end wall 14a. An engine fuel supply passage (not shown) is connected to the fuel outlet pipe 16.

  As shown in FIGS. 1, 3, and 4, a bearing boss 17 having a bottomed shaft hole 17a that opens into the motor housing 4 is provided at the center of the end wall 14a. A bearing bush 18 which is integrally formed so as to project from the bearing boss 17 and is arranged coaxially with the bearing boss 17 is fixed to the inner housing 7b of the pump housing 7, and the bearing boss 17 and the bearing bush 18 support the rotor shaft 6a. Both ends are rotatably supported.

  A hard coating made of diamond-like carbon is formed on at least one of the inner peripheral surface of the bearing boss 17 and the outer peripheral surface of the rotor shaft 6a that rotates and slides.

  A planar commutator 21 connected to the rotor coil 20 is fixed to the end of the rotor on the terminal holder 14 side.

  On the other hand, on the end wall 14a of the terminal holder 14, a pair of cylindrical brush guides 22 and 22 are formed integrally with the bearing boss 17 therebetween, and one end of each of the brush guides 22 and 22 is connected to the end wall 14a. The other end protrudes short from the outer surface of the end wall 14a. The brush guides 22 and 22 have guide holes 22a and 22a having a bottomed and irregular cross-section that open in the motor housing 4 in parallel with the shaft hole 17a of the bearing boss 17, and the guide holes 22a and 22a include A pair of brushes 23, 23 having different cross-sections that are in sliding contact with the commutator 21 are slidably fitted, and coil springs 24, 24 for urging the brushes 23, 23 in the pressure contact direction with the commutator 21 are housed. Is done. The pair of brushes 23, 23 are connected to the pair of terminals 19, 19 via lead wires 25, 25.

  Between the brush guides 22 and 22 and the bearing boss 17, gaps 27 and 27 are provided to separate them from each other.

  The brush guides 22, 22 have first cutout grooves 28, 28 extending in the axial direction on the side opposite to the bearing boss 17, and second cutout grooves 29, 29 extending in the axial direction on the side adjacent to the bearing boss 17. It is formed. The lead wires 25 and 25 are movably disposed in the first cutout grooves 28 and 28.

  Now, the pair of power supply terminals 19 and 19 and the mounting structure to these terminal holders 14 will be described.

  As shown in FIGS. 1, 2, 5, and 6, the end wall 14 a of the terminal holder 14 is provided with a pair of terminal attachment holes 15, 15 penetrating in the axial direction. , 15 is defined as an inlet 15a on the side opened in the terminal holder 14 and an outlet 15b on the opposite side. A pair of terminals 19 and 19 are press-fitted into these terminal mounting holes 15 and 15 from the inlet 15a toward the outlet 15b. Each terminal mounting hole 15 and terminal 19 are in the shape of a strip having a rectangular cross section, and as shown in FIGS. 5 to 7, a portion that penetrates the terminal mounting hole 15 of each terminal 19 has a press-fit portion 19 b and , A loose portion 19d having a smaller width and thickness than the press-fit portion 19b, and a wedge-shaped seal step portion 19c for connecting the press-fit portion 19b and the loose portion 19d are provided. A locking hole 30 penetrating in the direction is formed. The press-fitting portion 19b is connected to the base end portion 19a of the terminal 19 disposed in the terminal holder 14, and the idler portion 19d continues to the tip end portion 19e in the coupler 26. On the other hand, each terminal mounting hole 15 is formed so that the width and thickness are smaller than that of the press-fitting portion 19b of the terminal 19 in consideration of a predetermined press-fitting allowance and larger than that of the loose portion 19d. A locking projection 31 that elastically engages with the locking hole 30 is integrally provided on the inner surface of the terminal mounting hole 15. The end face of the locking projection 31 on the inlet 15a side of the terminal mounting hole 15 is formed on an inclined surface 31a that is inclined upward toward the outlet 15b of the terminal mounting hole 15.

  Thus, if the terminal 19 is fitted into the terminal mounting hole 15 of the terminal holder 14 by a predetermined press-fitting load from the inlet 15a to the outlet 15b, the press-fitting portion 19b is press-fitted to the inner surface of the terminal mounting hole 15. At the same time, when the wedge-shaped seal step portion 19c bites into the inner surface of the terminal mounting hole 15, and when the loose coupling portion 19d is loosely engaged with the terminal mounting hole 15, the locking projection 31 on the inner surface of the terminal mounting hole 15 becomes loose. The engagement hole 30 is engaged. In this case, the end face 19e of the terminal 19 passes through the terminal mounting hole 15 because the end face of the locking projection 31 on the inlet side of the terminal mounting hole 15 is a slope 31a rising toward the outlet 15b. Since the slant 31a slides and bends, and the locking projection 31 is also elastically deformed at the same time, the locking projection 31 can be smoothly engaged with the locking hole 30. The engagement of the locking projection 31 and the locking hole 30 ends the insertion of the terminal 19 into the terminal mounting hole 15.

  As shown in FIGS. 3, 4 and 7, each terminal 19 is bent and extended from one side edge of the base end portion 19a, and is arranged on one side of the corresponding brush guide 22. The first extension portion 32 and the second extension portion 33 bent from the tip of the first extension portion 32 so as to surround the corresponding one of the brush guides 22 are integrally formed. The first extension portion 32 is provided with a lead wire connecting piece 34, and the second extension portion 33 is integrally provided with a stopper piece 35 inserted and arranged in the first notch groove 28 near the entrance of the corresponding brush guide 22. It is formed and this is opposed to the lead wire 25 that is connected to the brush 23 and can move through the first notch groove 28, so that it is prevented from coming out from the first notch groove 28.

  Next, the operation of this embodiment will be described.

  When electric power is supplied to the electric motor 2 through the terminals 19 and 19 and operated, the rotor shaft 6a drives the pump impeller 10 to rotate. When the pump impeller 10 rotates, fuel in a fuel tank (not shown) is sucked into the pump chamber 8 from the suction port 11, boosted and discharged to the discharge port 12, and after passing through the motor housing 4, the fuel outlet pipe 16 To the engine fuel intake passage (not shown).

  In such an electric pump device 1, the bearing boss 17 formed integrally with the end wall 14 a of the terminal holder 14 made of synthetic resin for holding the pair of terminals 19, 19 of the motor housing 4, and the bearing boss 17 Between the pair of brush guides 22 and 22 arranged in parallel with each other, gaps 27 and 27 for separating and separating them are provided, so that the terminal holder 14, the bearing boss 17 and the brush guides 22 and 22 are integrally formed. Even if sink marks occur in the bearing boss 17 and the brush guides 22 and 22 respectively, the bearing boss 17 and the brush guides 22 and 22 block the influence of sink marks from each other by the gaps 27 and 27. Therefore, the bearing boss 17 and the brush guides 22 and 22 can be formed with high precision, respectively, and the rotor shaft 6a supported on the bearing boss 17 can be prevented from rotational vibration and early wear, thereby improving durability. At the same time, the sliding stability of the brushes 23, 23 fitted to the brush guides 22, 22 can be improved. Thus, integrally forming the bearing boss 17 and the brush guide 22 on the terminal holder 14 is effective in reducing the number of parts and, in turn, simplifying the structure, and reducing the cost of the electric pump device. Can contribute.

  Further, since the peripheral walls of the brush guides 22 and 22 are divided into two by the first and second cutout grooves 28 and 29; 28 and 29 extending in the axial direction, even if the cross-sectional shape is irregular, the brush guide 22 due to sink marks. , 22 can be minimized, and the sliding stability of the brushes 23, 23 can be further improved. Moreover, since the first cutout grooves 28 and 28 are used for the passages of the lead wires 25 and 25 connecting the brushes 23 and 23 and the terminals 19 and 19, the first cutout grooves 28 and 28 can contribute to simplification of the structure.

  Further, since a hard coating made of diamond-like carbon is formed on at least one of the inner circumferential surface of the bearing boss 17 and the outer circumferential surface of the rotor shaft 6a rotatably supported by the bearing boss 17, diamond-like carbon is formed. Therefore, the frictional resistance between the bearing boss 17 and the rotor shaft 6a can be reduced, so that the wear resistance is ensured even though the bearing boss 17 is made of synthetic resin. be able to.

  On the other hand, each power supply terminal 19 press-fits its press-fitting portion 19 b into the terminal mounting hole 15 of the terminal holder 14, and elastically attaches the locking projection 31 on the inner surface of the terminal mounting hole 15 to the locking hole 30 of the terminal 19. Can be firmly coupled to the terminal holder 14, thus preventing the press-fitting portion from loosening for a long period of time and reliably preventing leakage of high-pressure fuel from the motor housing 4 through the terminal mounting hole 15. can do.

  In particular, the terminal 19 is formed with a wedge-shaped seal step portion 19c that bites into the inner surface of the terminal mounting hole 15 adjacent to the press-fitting portion 19b. Can be reliably prevented, and high pump efficiency can be maintained for a long time. Further, the terminal 19 is formed with a loose portion 19d that is loosely coupled to the terminal mounting hole 15 adjacent to the seal step portion 19c, and the locking hole 30 is provided in the loose portion 19d. Since the joining portion 19d can be bent in the terminal mounting hole 15, the engaging hole 30 and the engaging protrusion 31 can be easily elastically engaged, and the assembling property of the terminal 19 is good.

  In addition, since the terminal is provided with a stopper piece 35 inserted and arranged in the first notch groove 28 in the vicinity of the entrance of the corresponding brush guide 22, the coil spring 24 and the brush are connected to the brush guide 22 of the terminal holder 14 during assembly. 23 is inserted and the lead wire 25 is disposed in the first notch groove 28, and then the terminal 19 is press-fitted into the terminal mounting hole 15 and set at a fixed position. It is disposed in the notch groove 28 and occupies a position that prevents the lead wire 25 from coming out of the first notch groove 28, thereby preventing the brush 23 from being detached from the brush guide 22 by the biasing force of the coil spring 24. Can do. Accordingly, when the brush guide 22 is subsequently assembled to the motor housing 4, the brush 23 can be accurately brought into pressure contact with the commutator 21. Of course, if the brush 23 is brought into pressure contact with the commutator 21, the brush 23 sinks into the brush guide 22 and the lead wire 25 is separated from the stopper piece 35.

  In this way, the lead wire 25 is received by the stopper piece 35 in the assembly process to prevent the brush 23 from coming out of the brush guide 22, so that excessive tension by the coil spring 24 does not act on the lead wire 25. Therefore, the durability can be improved, and the increase in the number of parts can be suppressed by connecting the stopper piece 35 to the terminal 19.

  The present invention is not limited to the above embodiment, and various design changes can be made without departing from the scope of the invention. For example, a choke coil for noise prevention can be connected to the lead wire 25 between the brush 23 and the terminal 19.

The longitudinal cross-sectional view (1-1 sectional view taken on the line of FIG. 2) of the electric pump apparatus which concerns on the Example of this invention. FIG. 2 is an enlarged view of part 2 of FIG. 1. FIG. 3 is a sectional view taken along line 3-3 in FIG. 1. FIG. 4 is a sectional view taken along line 4-4 of FIG. FIG. 5 is an enlarged view of part 5 of FIG. FIG. 6 is a sectional view taken along line 6-6 of FIG. The perspective view of a terminal.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Electric pump apparatus 2 ... Electric motor 3 ... Pump (fuel pump)
6 ... rotor 6a ... rotor shaft 14 ... terminal holder 15 ... terminal mounting hole 17 ... bearing boss 19 ... terminal 19b ... press-fit portion 19c ... ··· Stage step portion 19d ··············· commutator 22 ························································

Claims (3)

A pump (3) driven by the rotor (6) is connected to one end of the electric motor (2), and a terminal holder (14) made of synthetic resin is connected to the other end, and the terminal holder (14) is provided. In the electric pump device formed by press-fitting and connecting the power feeding terminal (19) from the inside of the terminal holder (14) to the terminal mounting hole (15) formed,
A locking hole (30) is provided in a portion of the terminal (19) facing the terminal mounting hole (15), and a locking projection (31) that elastically engages with the locking hole (30) is provided in the terminal. An electric pump device characterized by projecting from the inner surface of the mounting hole (15). The electric pump device according to claim 1,
A press-fitting portion (19b) press-fitted to the terminal (19) on the terminal attachment hole (15) on the inlet (15a) side, and loose on the terminal attachment hole (15) on the outlet (15b) side. A mating part (19d) to be fitted and a wedge-shaped seal step part (19c) between the press-fitting part (19b) 7) and the mating part (19d) and biting into the inner surface of the terminal mounting hole (15) are formed. The electric pump device is characterized in that the locking hole (30) is provided in the loose coupling portion (19d). The electric pump device according to claim 1 or 2,
A bearing boss (17) that rotatably supports one end of the rotor shaft (6a) of the rotor (6) on the terminal holder (14), and a brush (slidably contacting the commutator (21) of the rotor (6)) 23) An electric pump device characterized in that a cylindrical brush guide (22) for holding 23) is integrally formed.

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