Brush device and fuel supply device provided with said brush device

Abstract

A brush device (44) feeds power to a commutator (32) having a contact surface rotating together with a motor (31), the brush device (44) comprising: a brush (42) that slidably abuts the contact surface; a brush insertion hole (41b) into which the brush (42) is inserted; and a pressing part (43) that presses the brush (42) against the contact surface. The inner wall (41c) of the brush insertion hole (41b) is formed from a non-swelling material. Therefore, even if a motor cover (41) swells, the clearance between the brush (42) and the brush insertion hole (41b) can be maintained in an initial state.

Description

Brush device and fuel supply device equipped with the brush device

[0001] The present disclosure relates to a brush device and a fuel supply device including the brush device.

[0002] In order to achieve the designed rotation speed of a brushed motor, which is a component of a fuel supply system, it is important to increase the contact area between the sliding surfaces of the brushes and the commutator and make it easier for current to flow from the brushes to the commutator.When the motor is running, the rectangular brushes come into contact with the commutator at an angle due to the clearance between them and the brush insertion holes in the motor cover, so the brushes and commutator come into line contact, reducing the contact area.

[0003] A brush device is disclosed in which the brush end face is inclined so that the contact surfaces of the brush and commutator are parallel when the brush is inclined, thereby facilitating surface contact between the brush and the commutator.

[0004] JP 2008-79388 A

[0005] However, because the fuel supply device is used in gasoline and the motor cover is made of resin, it swells over time, causing the brush insertion holes to deform and widen toward the commutator. Therefore, even with the structure of Patent Document 1, the brushes tilt significantly when the motor is running, making it difficult to maintain surface contact between the brushes and the commutator.

[0006] The present disclosure discloses technology for solving the above-mentioned problems, and aims to provide a brush device and a fuel supply device that can suppress deformation of the inner wall of the brush insertion hole even when the motor cover swells, and can maintain the clearance between the brush and the brush insertion hole in its initial state.

[0007] The brush device of the present disclosure is a brush device that supplies power to a commutator having a contact surface that rotates together with a motor, and includes a brush that slidably abuts on the contact surface, a brush insertion hole into which the brush is inserted, and a biasing portion that presses the brush against the contact surface, the inner wall of the brush insertion hole being made of a non-swelling material.The fuel supply device of the present disclosure is a brush device that is disposed inside a fuel tank and supplies fuel to the outside of the fuel tank.

[0008] According to the brush device of the present disclosure, a brush device can be obtained in which the clearance between the brush and the brush insertion hole can be maintained close to the initial state, and the brush and the commutator can maintain surface contact. According to the fuel supply device of the present disclosure, a fuel supply device can be obtained in which the clearance between the brush and the brush insertion hole can be maintained close to the initial state, and the brush and the commutator can maintain surface contact.

[0009] Fig. 2A is a configuration diagram of a fuel supply device including a brush device according to embodiment 1. Fig. 2B is an explanatory diagram of a brush device of a comparative example according to embodiment 1. Fig. 2C is a cross-sectional view of a fuel supply device according to embodiment 1. Fig. 2D is a cross-sectional view of a fuel supply device according to embodiment 2.

[0010] Embodiment 1. Embodiment 1 relates to a brush device that supplies power to a commutator having a contact surface that rotates together with a motor, the brush device comprising a brush that slidably contacts the contact surface, a brush insertion hole into which the brush is inserted, and a spring that presses the brush against the contact surface, the inner wall of the brush insertion hole being made of a non-swelling material. The embodiment also relates to a fuel supply device equipped with this brush device.

[0011] A fuel supply device including a brush device according to the first embodiment will be described below with reference to FIG. 1, which is a structural diagram of the fuel supply device, FIGS. 2A and 2B, which are explanatory diagrams of a brush device of a comparative example, and FIG. 3, which is a cross-sectional diagram of the fuel supply device. In each drawing, identical or corresponding parts are designated by the same reference numerals, and duplicated explanations will be omitted. In the following description, unless otherwise specified, the terms "axis (direction)," "radius (direction)," and "circumference (direction)" refer to the rotation axis (direction), radius (direction), and circumference (direction) of a cylindrical coordinate system centered on the rotation axis of the motor of the fuel supply device.

[0012] First, the configuration and function of a fuel supply device 10 including a brush device according to a first embodiment will be described with reference to FIG. 1, which is a configuration diagram of the fuel supply device 10. Note that FIG. 1 is a cross-sectional view taken along line B-B in FIG. 3 so that the internal structure of the fuel supply device 10 can be easily understood. The fuel supply device 10 is an in-tank fuel supply device that is installed inside a fuel tank of, for example, a vehicle, and supplies fuel therein to an engine. The fuel supply device 10 is composed of a pump unit 20, a motor unit 30, and a power supply unit 40. The pump unit 20 pressurizes the drawn fuel, the motor unit 30 drives the pump unit 20, and the power supply unit 40 supplies external power to the motor unit.

[0013] The fuel supply device 10 includes a substantially cylindrical pump case 11, and a magnet 12 is disposed annularly in the circumferential direction on the inner wall surface of the pump case 11. A motor 31 is disposed on the inner circumferential side of the magnet 12, concentrically with the annular magnet 12.

[0014] Next, we will explain the configurations and functions of the pump unit 20, motor unit 30, and power supply unit 40. The pump unit 20 is fixed to the lower end of the pump case 11 and is composed of a casing 21, a casing cover 22, and an impeller 23. The impeller 23 is rotatably housed between the casing 21 and the casing cover 22. The casing cover 22 is also provided with a fuel suction port 22a for drawing in fuel.

[0015] The motor section 30 includes a motor 31, which is a DC motor with brushes, and a commutator 32, which is installed axially above the motor 31 and rotates together with the motor shaft 31a.

[0016] The power supply unit 40 includes a motor cover 41 fixed to the upper end of the pump case 11. A fuel discharge port 41a is provided at the top of the motor cover 41. A brush insertion hole 41b is formed at the bottom of the motor cover 41, into which a brush 42 and a spring 43 serving as a biasing member are inserted.

[0017] Next, we will explain the brush device 44, which is a feature of the first embodiment. The brush device 44 is made up of brushes 42, springs 43 which act as urging members, and brush insertion holes 41b formed in the motor cover 41. The brushes 42 are housed in the brush insertion holes 41b and are pressed against the commutator upper end surface 32a, which is the contact surface of the commutator 32 that rotates together with the motor 31, by the springs 43 housed above the brushes 42.

[0018] Next, the path for supplying power to the motor 31 will be described. Power is supplied to the brushes 42 from a power supply terminal 45 (see FIG. 3) located at the top of the motor cover 41 via a pigtail 46. The brushes 42 are pressed down by a spring 43, which passes current through the commutator 32, causing the motor 31 to rotate. The impeller 23 rotates as the motor 31 rotates. The pigtail 46 is inserted into a pigtail insertion hole 42a drilled in the side of the brush 42, and is connected to the brush 42 by filling the gap with metal powder and adhesive.

[0019] Next, we will explain the flow of fuel within the fuel supply device 10. Fuel in a fuel tank (not shown) is sucked up through the fuel intake port 22a of the casing cover 22, passes through the motor unit 30, and is discharged from the fuel discharge port 41a. Therefore, the inner space of the casing 21, including the brush insertion hole 41b, is filled with fuel.

[0020] The inner space of the casing 21 is filled with fuel, so if the motor cover 41 is made of a thermoplastic resin such as polyacetal, it will swell if immersed in fuel for a long period of time, causing deformation of the brush insertion holes 41b.

[0021] The effects of deformation of the brush insertion hole 41b will be described with reference to FIGS. 2A and 2B, which are explanatory diagrams of a comparative example. Note that reference numerals have not been changed to simplify the description. FIG. 2A shows the brush insertion hole 41b and the brush 42 in the motor cover 41 before swelling. FIG. 2B shows the deformation and tilt of the brush 42 after swelling. If the motor cover 41 is made of thermoplastic resin, swelling due to fuel causes the brush insertion hole 41b to deform and widen toward the commutator upper end surface 32a. This increases the tilt of the brush 42, making it more likely to come into line contact with the commutator upper end surface 32a.

[0022] Next, a brush device 44 according to a first embodiment, which addresses the above-described problems, will be described with reference to FIG. 3 . FIG. 3 is a cross-sectional view taken along the line A-A in FIG. 1 . That is, a view of the motor cover 41 taken along a plane perpendicular to the axial direction at the commutator upper end surface 32a, as viewed from the axially lower side. As shown in FIG. 3 , a non-swelling material, such as a metal or ceramic material, is provided on the inner wall 41c of the brush insertion hole 41b. By providing a non-swelling material on the inner wall 41c of the brush insertion hole 41b, the brush device 44 according to this first embodiment can maintain the shape of the brush insertion hole 41b even if the motor cover 41 swells. This allows the clearance between the brush 42 and the brush insertion hole 41b to be maintained close to its initial state, thereby maintaining surface contact between the brush 42 and the commutator 32.

[0023] If the brush device 44 is installed inside a fuel supply device that supplies fuel to the outside of a fuel tank, the clearance between the brush 42 and the brush insertion hole 41b can be maintained close to the initial state, and the brush 42 can maintain surface contact with the commutator 32. This allows the fuel supply device 10 to continue stable operation for a long period of time.

[0024] 3, the non-swelling material is provided on the entire inner wall 41c of the brush insertion hole 41b, following the shape of the brush 42. However, in order to maintain surface contact between the brush 42 and the commutator upper end surface 32a, it is also possible to provide a non-swelling material on at least the circumferential inner wall 41d facing in a direction perpendicular to the motor rotation direction, thereby suppressing spreading deformation.

[0025] As explained above, the brush device of the first embodiment can maintain the clearance between the brush and the brush insertion hole in a state close to the initial state, and can maintain surface contact between the brush and the commutator.

[0026] Second Embodiment In a second embodiment, the power supply terminal and the inner wall of the brush insertion hole are integrally formed.

[0027] The brush device of the second embodiment will be described with reference to Fig. 4, which is a cross-sectional view of the fuel supply device, focusing on the differences from the first embodiment. In the configuration diagram of the second embodiment, parts that are the same as or equivalent to those of the first embodiment are given the same reference numerals. In order to distinguish from the first embodiment, the second embodiment is referred to as a fuel supply device 110, a brush device 144, and an inner wall 141c of the brush insertion hole.

[0028] In the first embodiment, the brush 42 receives power from the power supply terminal 45 via the pigtail 46. In the second embodiment, as shown in FIG. 4, the inner wall 141c of the brush insertion hole 41b is made of a non-swelling material, such as a metal or ceramic material that is also conductive, and the power supply terminal 145 and the inner wall 141c are integrated. This allows current to flow from the power supply terminal 145 to the brush 42 via the inner wall 141c. This eliminates the need for a pigtail, reducing the number of parts.

[0029] As described above, the brush device of the second embodiment can maintain the clearance between the brush and the brush insertion hole close to the initial state, and can maintain surface contact between the brush and the commutator. In addition, the number of parts can be reduced.

[0030] Although various exemplary embodiments and examples are described in this disclosure, the various features, aspects, and functions described in one or more embodiments are not limited to the application of a particular embodiment, but may be applied to the embodiments alone or in various combinations. Therefore, countless variations not illustrated are anticipated within the scope of the technology disclosed in this specification. For example, this includes cases where at least one component is modified, added, or omitted, or where at least one component is extracted and combined with components of another embodiment.

[0031] 10, 110 Fuel supply device, 11 Pump case, 12 Magnet, 20 Pump section, 21 Casing, 22 Casing cover, 22a Fuel intake port, 23 Impeller, 30 Motor section, 31 Motor, 31a Motor shaft, 32 Commutator, 32a Commutator upper end surface, 40 Power supply section, 41 Motor cover, 41a Fuel discharge port, 41b Brush insertion hole, 41c, 141c Inner wall, 41d Circumferential inner wall, 42 Brush, 42a Pigtail insertion hole, 43 Spring, 44, 144 Brush device, 45, 145 Power supply terminal, 46 Pigtail.

Claims

1. A brush device for supplying power to a commutator having a contact surface that rotates with a motor, the brush device comprising: a brush slidably contacting the contact surface; a brush insertion hole into which the brush is inserted; and a biasing portion that presses the brush against the contact surface, wherein an inner wall of the brush insertion hole is made of a non-swellable material.

2. The brush device according to claim 1, wherein at least a circumferential inner wall of the inner wall of the brush insertion hole facing in a direction perpendicular to a rotation direction of the motor is made of a non-swellable material.

3. The brush device according to claim 1, wherein the entire inner wall of the brush insertion hole is made of a non-swellable material.

4. The brush device according to any one of claims 1 to 3, wherein the inner wall of the brush insertion hole and a power supply terminal for supplying electricity to the motor are integrally structured.

5. The brush device according to any one of claims 1 to 4, wherein the non-swellable material is a metal material or a ceramic material.

6. A fuel supply device in which the brush device according to any one of claims 1 to 5 is disposed inside a fuel tank and supplies fuel to the outside of the fuel tank.

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