KR-20260062575-A - Brush structure that maintains ripple current waveform stably and DC motor device

Abstract

A brush structure and motor device for stably maintaining a ripple current waveform according to the present invention comprises, as a structure of a brush that supplies current to a commutator constituting the rotor of a DC motor, a rod-shaped body; and a contact portion formed at one end of the body and slidingly contacting the commutator; wherein the contact portion comprises: a first region slidingly contacting the commutator; a second region disposed spaced apart from the first region and physically separated from the first region; a third region disposed spaced apart from the first region and the second region, respectively, so as to be physically separated; and a fourth region disposed spaced apart from the first region, the second region and the third region, respectively, so as to be physically separated.

Inventors

• 강병훈

Assignees

• 디와이오토 주식회사

Dates

Publication Date

20260507

Application Date

20241029

Claims (8)

1. As a structure of brushes that supply current to the commutator constituting the rotor of a DC motor, A rod-shaped body; and A contact portion formed at one end of the body and slidingly contacting the commutator; is provided, The above contact portion comprises a first region that is in sliding contact with the commutator; A second area positioned to be spaced apart from the first area and physically separated from the first area; A third region spaced apart from the first region and the second region so as to be physically separated from each of them; and A brush structure in which a ripple current waveform is stably maintained, characterized by including a fourth region arranged in a spaced-apart state so as to be physically separated from the first region, the second region, and the third region, respectively.
2. In paragraph 1, A brush structure in which a ripple current waveform is stably maintained, characterized in that the line connecting the center of the first region, the center of the second region, the center of the third region, and the center of the fourth region forms a rectangle.
3. In paragraph 1 or 2, A brush structure in which a ripple current waveform is stably maintained, characterized in that the contact portion is provided with a discharge groove for discharging dust or particles generated by friction between the brush and the commutator in the rotational direction of the commutator.
4. In paragraph 3, A brush structure in which a ripple current waveform is stably maintained, characterized in that the discharge groove is formed between the first region and the fourth region.
5. In paragraph 3, A brush structure in which a ripple current waveform is stably maintained, characterized in that the discharge groove is formed between the second region and the third region.
6. In paragraph 1, A brush structure in which a ripple current waveform is stably maintained, characterized in that the first region, the second region, the third region, and the fourth region have irregularities in the shape of valleys and crests, and the irregularities extend in a direction parallel to the rotational direction of the commutator.
7. In paragraph 3, A brush structure in which a ripple current waveform is stably maintained, characterized in that the discharge groove is formed to become progressively narrower as it moves away from the commutator.
8. A DC motor device including a brush structure according to paragraph 1.

Description

Brush structure that maintains ripple current waveform stably and DC motor device The present invention relates to the structure of a brush for a DC motor, and more specifically, to the shape of a brush in contact with a commutator. Generally, a motor device comprises a rotor and a stator. The rotor includes a commutator that rotates integrally with the output shaft of the motor. The stator includes brushes for supplying current to the commutator. Generally, the commutator consists of a plurality of commutator segments arranged spaced apart from each other along the circumferential direction of the output shaft of the motor. The brushes supply current to the commutator while making sliding contact with the commutator segments. In motors having such a structure, ripple current is used as a factor to control the rotation of the motor. Ripple current is generally used as an electrical signal for position control or speed control in motors that perform actuator functions, such as DC motors, sunroof motors, seat motors, and wiper motors mounted in vehicles. Compared to conventional Hall sensors used to perform the same function, it is cheaper, does not require the installation of additional sensors, and can obtain a relatively large number of pulses, which has the advantage of enabling more precise control of ripple current in motor devices. Referring to FIG. 1, the conventional brush (1) structure is provided with a contact portion (2) separated in the left and right directions along the rotational direction of the commutator (not shown). However, in the conventional structure, the brush (1) can move in the left and right or up and down directions while the brush (1) and the commutator are in sliding contact. In this process, the two surfaces constituting the contact portion (2) do not properly contact the commutator, resulting in a problem of reduced electrical conductivity. Consequently, this affects the waveform of the ripple current. If the waveform of the ripple current changes, the motor cannot be properly controlled, which may lead to quality issues with the motor. Figure 1 is a drawing showing an example of a conventional brush structure. FIG. 2 is a drawing showing a brush structure according to the present invention. Figure 3 is a drawing showing the state in which the brush structure and the commutator shown in Figure 1 are in contact. Figure 4 is a cross-sectional view along line IV-IV shown in Figure 3. Figure 5 is a cross-sectional view along line V-V shown in Figure 3. FIG. 6 is a diagram showing the ripple current measurement results according to the durability test of a motor with the brush structure shown in FIG. 1 and a motor with the brush structure of the present invention shown in FIG. 2. Embodiments of the present invention are described below with reference to the attached drawings so that those skilled in the art can easily implement them. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein. Furthermore, in describing preferred embodiments of the present invention in detail, specific descriptions of related known functions or configurations are omitted if it is determined that such detailed descriptions would unnecessarily obscure the essence of the present invention. Additionally, the same reference numerals are used throughout the drawings for parts having similar functions and operations. The term 'comprising' a component means that, unless specifically stated otherwise, it does not exclude other components but rather allows for the inclusion of additional components. Specifically, terms such as "comprising" or "having" are intended to indicate the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof. Singular expressions include plural expressions unless the context clearly indicates otherwise. Additionally, the shapes and sizes of elements in drawings may be exaggerated for clearer explanation. FIG. 2 is a drawing showing a brush structure according to the present invention. FIG. 3 is a drawing showing the state in which the brush structure illustrated in FIG. 1 is in contact with the commutator. FIG. 4 is a cross-sectional view along line IV-IV illustrated in FIG. 3. FIG. 5 is a cross-sectional view along line V-V illustrated in FIG. 3. FIG. 6 is a drawing showing the ripple current measurement results according to an endurance test of a motor with the brush structure illustrated in FIG. 1 and a motor with the brush structure of the present invention illustrated in FIG. 2. Referring to FIGS. 2 through 6, in a motor device, a commutator (100) constitutes a rotor. An element that supplies current to the commutator (100) is a brush (10). The commutator (100) is composed