JP2005307768A - Electric fuel pumping installation - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the rotational vibration and early abrasion of a rotor shaft by forming a bearing boss and a brush guide with high accuracy without mutually having influences of shrinkage in an electric fuel pumping installation. <P>SOLUTION: A clearance 27 mutually independently separating the bearing boss 17 and brush guide 22 is arranged between the bearing boss 17 and brush guide 22, in the electric fuel pumping installation designed that a pump housing 7 is connected to one end of a motor housing 4, a synthetic resin-made terminal holder 24 is connected to the other end of the motor housing 4, the bearing boss 17 supporting the rotor shaft 6a and a pair of cylindrical brush guides 22 arranged across the bearing boss 17 are integrally formed on the end wall 14a of the terminal holder 14, a brush 23 to be in slidable contact with the surface shape commutator 21 of a rotor 6 is fitted to the brush guide 22, and a spring 24 energizing the brush 23 in a pressure contact direction with the commutator 21 is stored in the brush guide 22. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  According to the present invention, a pump housing of a fuel pump driven by a rotor shaft coupled to a rotor of an electric motor is coupled to one end of a motor housing of the electric motor, and power is supplied to the electric motor at the other end of the motor housing. A synthetic resin terminal holder for supporting the terminal for use is coupled, and a bearing boss for supporting the rotor shaft and a pair of brushes arranged parallel to the bearing boss on the end wall of the terminal holder. A guide is integrally formed, and a brush that is slidably engaged with a planar commutator provided at one end of the rotor is slidably fitted to the brush guide, and the brush is biased in the direction of pressure contact with the commutator. The present invention relates to an electric fuel pump device that houses a spring to be operated.

Such an electric fuel pump device is already known as disclosed in Patent Document 1 below.
JP 11-44270 A

  In this type of conventional electric fuel pump device, the bearing boss and the brush guide are integrally formed with the terminal holder in a state of being integrally connected to each other so as to have a common boundary wall. In such a case, sink marks at the time of molding of the bearing boss and the brush guide often affect each other, thereby reducing the molding accuracy of the bearing boss and the brush guide. , This causes rotational vibration and early wear of the rotor shaft.

  The present invention has been made in view of such circumstances. The bearing boss and the brush guide can be molded with high accuracy without causing the influence of sink marks. An object of the present invention is to provide an electric fuel pump device that can prevent the above-described problem.

  To achieve the above object, according to the present invention, a pump housing of a fuel pump driven by a rotor shaft coupled to a rotor of an electric motor is coupled to one end of a motor housing of the electric motor, and the other end of the motor housing is coupled. A synthetic resin terminal holder that supports a power supply terminal for the electric motor is coupled to the end portion, and an end wall of the terminal holder has a bearing boss for supporting the rotor shaft and a bearing boss sandwiched between the bearing boss and the terminal boss. A pair of brush guides arranged in parallel is integrally formed, and a brush that is slidably engaged with a planar commutator provided at one end of the rotor is slidably fitted to the brush guide. In the electric fuel pump device comprising a spring energizing in the direction of pressure contact with the commutator, these are separated from each other between the bearing boss and the brush guide. In that a gap to be standing a first feature.

  In addition to the first feature, the present invention provides a hard coating made of diamond-like carbon on at least one of the inner peripheral surface of the bearing boss and the outer peripheral surface of the rotor shaft that rotates and slides on the bearing boss. The formation is a second feature.

  According to the first feature of the present invention, when the bearing boss and the brush guide are integrally formed on the terminal holder, even if sink marks occur in each, the influence of the sink marks is caused by the gap between the bearing boss and the brush guide. Cut off. Therefore, it is possible to mold the bearing boss and brush guide with high accuracy, and it is possible to improve durability by preventing rotational vibration and premature wear of the rotor shaft supported by the bearing boss. The sliding stability of the brush to be fitted can be improved.

  According to the second feature of the present invention, since the hard coating made of diamond-like carbon has a very low coefficient of friction, the rotational frictional resistance between the bearing boss and the rotor shaft can be reduced. Despite being made of synthetic resin, its wear resistance can be improved.

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

  FIG. 1 is a longitudinal sectional view of the electric fuel pump device according to the present invention (cross-sectional view taken along line 1-1 of FIG. 2), 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.

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

  The electric motor 2 is made of a metal and has a cylindrical motor housing 4. A stator 5 made of a permanent magnet is fixed to the inner peripheral surface of the electric motor 2, and a rotor 6 is rotatably disposed in the stator 5.

  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 intake port 11 communicates with the fuel oil level in a 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 pair of terminal holes 15, 15 are provided in the end wall 14 a of the terminal holder 14, and the pair of terminals 19, 19 are fixed to the terminal holes 15, 15 by press-fitting. A coupler 26 surrounding the outer ends of the terminals 19 and 19 is integrally formed on the end wall 14a.

  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 protrude from the bearing boss 17 and is coaxially disposed 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 are used to form 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.

  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 fuel pump device 1, the bearing boss 17 formed integrally with the end wall 14 a of the terminal holder 14 made of synthetic resin that holds the pair of terminals 19, 19 of the motor housing 4, and the bearing boss Between the pair of brush guides 22 and 22 arranged in parallel with the pin 17 therebetween, 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 integrated. Even if sink marks occur in the bearing boss 17 and the brush guides 22 and 22 during molding, 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 rotating vibration and premature wear to improve durability. At the same time, the sliding stability of the brushes 23, 23 fitted to the brush guides 22, 22 can be improved.

  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.

  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.

The longitudinal cross-sectional view (1-1 sectional view taken on the line of FIG. 2) of the electric fuel pump apparatus which concerns on 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.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Electric fuel pump apparatus 2 ... Electric motor 3 ... Fuel pump 4 ... Motor housing 6 ... Rotor 6a ... Rotor shaft 7 ... Pump housing 14 ... Terminal holder 14a ... End wall 17 ... Bearing boss 19 ... Terminal 21 ... Commutator 22 ... Brush guide 23 ... Brush 24 ... Spring 27 ... Gap

Claims (2)

A pump housing (7) of a fuel pump (3) driven by a rotor shaft (6a) coupled to a rotor (6) of the electric motor (2) is attached to one end of a motor housing (4) of the electric motor (2). A terminal holder (14) made of synthetic resin for supporting a power supply terminal (19) to the electric motor (2) is connected to the other end of the motor housing (4), and this terminal holder (14) The end wall (14a) has a bearing boss (17) for supporting the rotor shaft (6a) and a pair of cylindrical brush guides (22) arranged in parallel with the bearing boss (17). And a brush (23) slidably engaged with the planar commutator (21) provided at one end of the rotor (6) is slidably fitted to the brush guide (22). , This brush (23) commutator The electric fuel pump apparatus formed by housing a spring (24) for biasing the pressure contact direction and 21),
An electric fuel pump device characterized in that a gap (27) is provided between the bearing boss (17) and the brush guide (22) to separate them from each other. The electric fuel pump device according to claim 1,
A hard film 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 thereon, Electric fuel pump device.

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