JP5502585B2 - Brush holder and electric tool provided with brush holder - Google Patents

Description

  The present invention relates to a brush holder that holds a brush in sliding contact with a commutator attached to a rotating shaft of a motor and is fixed in a housing that houses the motor, and an electric tool including the brush holder.

  Patent Document 1 discloses an electric tool that enables a brush holder to be stably fixed to an intermediate region that extends inward in the longitudinal direction from an end region of a tool housing. The electric power tool disclosed in Patent Document 1 is configured such that a cover is attached to one end portion in the longitudinal direction of the tool housing, and a protrusion that extends in the longitudinal direction of the tool housing is formed in the internal space of the cover. . When the cover is attached to the tool housing along the longitudinal direction, the ridge portion contacts the pressed portion of the brush holder inserted into the intermediate region, and presses the brush holder in the insertion direction. As a result, the brush holder can be stably fixed to the intermediate region.

JP 2009-148855 A

  By the way, in said electric tool, when a brush slidably contacted with a commutator, high heat generate | occur | produced and this high heat might be transmitted to a tool housing through a brush holder from a brush. In such a case, there has been a concern that the tool housing located around the brush holder is thermally deformed.

  Further, when the periphery of the brush holder exceeds the heat-resistant temperature of the tool housing, the housing portion for fixing the brush holder is melted, so that the brush holder is fixed to the tool housing. When moving to the inner surface side of the rear cover covering the holder, there has been a concern that the inner surface of the rear cover is melted by the heat from the brush holder.

  This invention is proposed in view of such a situation, Comprising: It aims at providing the brush holder which can reduce the heat transmitted to the inner surface of a rear cover, and an electric tool provided with this brush holder.

According to a first aspect of the present invention, there is provided a brush holder for holding a brush in sliding contact with a commutator attached to a rotating shaft of a motor and fixing the brush holder in a housing for housing the motor . as, in the brush holder, formed by a heat-resistant resin, protrude with a gap between the inner surface of the housing in a state in which the brush holder is fixed in the housing to the inner surface of said housing, said A restriction member is provided for restricting the brush holder from coming into contact with the inner surface of the housing even when the fixing of the brush holder to the housing is released .

  According to a second aspect of the present invention, in the first aspect, the brush holder is provided with a protruding member that protrudes toward the inner surface of the housing, and the restricting member has an insertion hole through which the protruding member is inserted, After the protruding member is inserted into the insertion hole, the protruding member is bent in the insertion hole by bending the tip of the protruding member.

  According to a third aspect of the present invention, there is provided a commutator attached to a rotating shaft of a motor, a brush slidably contacting the commutator, a brush holder for holding the brush, and the motor being accommodated to fix the brush holder inside. The brush holder according to claim 1 or 2 is fixed in the housing.

According to the brush holder according to the invention of claim 1 and the electric tool according to the invention of claim 3, for example, the high heat generated when the brush is in sliding contact with the commutator melts the housing portion that fixes the brush holder. As a result of the release of the fixing of the brush holder to the housing, the brush holder may move to the inner surface side of the housing. Even in this case, a heat-resistant member can be interposed between the brush holder and the inner surface of the housing, and heat from the brush holder can hardly be transmitted to the inner surface.
According to the invention of claim 2, the restricting member can be fixed to the brush holder in a state where the protruding member is locked in the insertion hole. Therefore, the restricting member can be fixed to the brush holder with a simple configuration in which the tip of the protruding member inserted through the insertion hole is bent.

(A) A figure is a perspective view of the brush holder of this embodiment in one direction, (b) A figure is a perspective view of the brush holder in another direction. It is the figure which showed the state which fixed the brush holder to the rear housing of an electric disc grinder. It is the side view which notched a part of electric disc grinder which accommodated the brush holder holding the brush in the rear cover.

  An embodiment of the present invention will be described with reference to FIGS. The brush holder 1 shown in FIG. 1 holds a brush 80 (see FIG. 3) and urges the brush 80 against a commutator 70 (see FIG. 3) to make sliding contact. The brush holder 1 is made of metal and includes a brush accommodating portion 10, a spiral spring 20, a stopper 30, a protruding piece 40, and a brush holder fixing plate 50, as shown in FIG.

  The brush housing portion 10 is provided in the brush holder 1 so as to extend in a direction orthogonal to the rotation axis of the motor M (see FIG. 3) in a state where the surface facing the commutator 70 is open. In order to hold the brush 80 slidably, the brush accommodating portion 10 is formed so as to surround the brush 80 by left and right side walls, an upper wall, and a guide piece arranged to face the upper wall.

  The spiral spring 20 is supported by the spring support 2 of the brush holder 1. The end portion 21 of the spiral spring 20 is in contact with the rear end surface of the brush 80 and applies an elastic force to the commutator 70 side with respect to the brush 80 in a direction orthogonal to the rotation axis. Thereby, the front end surface of the brush 80 can be slidably contacted with the commutator 70.

  The stopper 30 is attached to the outer surface of the brush holder 1 in a direction perpendicular to the rotation axis. In the stopper 30, a facing surface 31 that faces an inner surface of a rear cover 63 (see FIG. 3), which will be described later, protrudes from the outer surface of the brush holder 1 to the inner surface side of the rear cover 63. Here, as the stopper 30, for example, a plate member made of a thermosetting heat-resistant resin made of a phenol resin is used. An insertion hole 32 passes through the stopper 30 in order to allow the following protruding piece 40 to be inserted. A concave groove 33 is provided in the insertion hole 32. The stopper 30 restricts the brush holder 1 from coming into contact with the inner surface of the rear cover 63, as will be described later. The stopper 30 is an example of a regulating member according to the present invention.

  The protruding piece 40 protrudes from the outer surface of the brush holder 1 toward the inner surface of the rear cover 63 in a direction parallel to the axial direction of the rotating shaft. After the protruding piece 40 is inserted into the insertion hole 32, the distal end portion 41 is bent so as to extend in a direction orthogonal to the axial direction. Thereby, as shown to (a) figure of FIG. 1, the front-end | tip part 41 is latched by said groove part 33. As shown in FIG. The protruding piece 40 is an example of a protruding member of the present invention.

  In the brush holder 1, the brush holder fixing plate 50 is disposed on the surface on the side where the opposing surface 31 of the stopper 30 protrudes. A hole 51 is formed through the brush holder fixing plate 50. FIG. 2 shows an example in which the brush holder 1 is fixed to the rear housing 62 of the electric disc grinder. The rear housing 62 is recessed with a brush holder accommodating space S1 that opens outward in the radial direction. Here, in order to fix the brush holder 1 to the rear housing 62, the screw 52 is inserted through the hole 51 and tightened into a screw hole (not shown) provided in the brush holder accommodation space S1.

  In FIG. 3, the electric disc grinder 60 which accommodated said brush holder 1 was illustrated. The electric disc grinder 60 includes a motor housing 61, a rear housing 62, a rear cover 63, and a gear housing 64. The electric disc grinder 60 is an example of the electric tool of the present invention.

  The motor housing 61 is formed in a cylindrical shape from synthetic resin. As shown in FIG. 3, the motor M is accommodated in the motor housing 61. The rotating shaft of the motor M is disposed in the front-rear direction (left-right direction in FIG. 3) of the electric disk grinder 60 (motor housing 61). The rotating shaft is supported by a bearing (not shown) and is rotatable. A commutator 70 is attached to the outer periphery of the rotating shaft.

  The rear housing 62 is made of synthetic resin and is connected to the rear end portion of the motor housing 61. The rear housing 62 is disposed so as to cover the commutator 70. The brush holder 1 is fixed to the rear housing 62 in the same manner as the example shown in FIG. As shown in FIG. 3, the brush 80 is inserted into the brush housing portion 10. The front end surface of the brush 80 is slidably pressed against the outer peripheral surface of the commutator 70 through the opening of the rear housing 62 by the elastic force of the spiral spring 20 described above. In the present embodiment, the two brushes 80 can be slidably contacted with the outer peripheral surface of the commutator 70 by fixing the brush holder 1 to two locations in the circumferential direction of the rear housing 62. A current is supplied to the commutator 70 through the brush 80.

  The rear cover 63 is formed of a synthetic resin and has a cylindrical shape with one end opened. The rear cover 63 is screwed to the rear housing 62 while being covered with the rear housing 62. Thereby, the brush holder 1 is accommodated in the rear cover 63, and the stopper 30 projects from the outer surface of the brush holder 1 to the inner surface side of the rear cover 63. At this time, a gap is formed between the opposing surface 31 (see FIG. 1) of the stopper 30 and the inner surface of the rear cover 63.

  The gear housing 64 is connected to the front end portion of the motor housing 61. Inside the gear housing 64, a grindstone rotational drive mechanism (not shown) is accommodated. The workpiece can be polished by rotating a grindstone (not shown) by a rotation drive mechanism.

  In the present embodiment, by using the brush holder 1 described above, heat is prevented from being transmitted to the rear cover 63 through the brush holder 1 as described below. As described above, when the brush 80 is in sliding contact with the commutator 70, a high temperature may occur. In this case, since the brush holder 1 is made of metal, heat conductivity is good, and high temperature is transmitted to the rear housing 62 through a screw attached to the brush holder fixing plate 50.

  Along with this, when the screwing portion of the brush holder 1 in the rear housing 62 exceeds the heat resistance temperature, the screwing portion is melted. As a result, the fixing of the brush holder 1 to the rear housing 62 is released, and the brush holder 1 may move from the brush holder housing space S1 toward the inner surface of the rear cover 63.

  In the present embodiment, as described above, since the facing surface 31 protrudes from the outer surface of the brush holder 1 to the inner surface side of the rear cover 63, the brush holder 1 is moved toward the inner surface of the rear cover 63. Even if it exists, the stopper 30 can be interposed between this inner surface and the brush holder 1 because the opposing surface 31 contacts the inner surface. Therefore, the brush holder 1 is restricted from contacting the inner surface. Since the stopper 30 is formed of a heat resistant resin, the high heat is prevented from being transmitted from the brush holder 1 to the inner surface of the rear cover 63 when the stopper 30 is in contact with the inner surface. The inner surface of the rear cover 63 is an example of the inner surface of the housing of the present invention.

<Effect of this embodiment>
In the brush holder 1 of this embodiment and the electric disc grinder 60 that accommodates the brush holder 1, as described above, the brush holder 1 may move from the brush holder accommodating space S <b> 1 toward the inner surface of the rear cover 63. In addition, a stopper 30 (heat-resistant resin) can be interposed between the inner surface and the brush holder 1. Therefore, the high heat generated when the brush 80 is in sliding contact with the commutator 70 can be hardly transmitted from the brush holder 1 to the inner surface.

  Further, as described above, after the protruding piece 40 is inserted into the insertion hole 32 of the stopper 30, the distal end portion 41 of the protruding piece 40 is bent and locked to the concave groove portion 33. For this reason, the stopper 30 can be attached to the outer surface of the brush holder 1 in a state where the tip 41 is engaged with the concave groove 32. Therefore, the stopper 30 can be fixed to the outer surface of the brush holder 1 with a simple configuration in which the distal end portion 41 of the protruding piece 40 inserted through the insertion hole 32 is bent.

  The present invention is not limited to the above-described embodiment, and can be implemented by appropriately changing a part of the configuration without departing from the spirit of the invention. In the embodiment described above, an example in which the stopper 30 is formed of a phenol resin has been described. However, the present invention is not limited thereto, and the stopper 30 may be formed of an appropriate thermosetting heat resistant resin such as an epoxy resin. .

  In the above-described embodiment, the motor housing 61 and the rear housing 62 are separately formed. However, the present invention is not limited thereto, and the motor housing 61 and the rear housing 62 may be integrally formed. Furthermore, although the example which accommodated the brush holder 1 in the electric disc grinder 60 was shown in embodiment mentioned above, you may accommodate the brush holder 1 in brush-type electric tools, such as an electric hammer, not only this. .

  1 .... Brush holder, 30 ... Stopper, 32 ... Insertion hole, 33 ... Groove, 40 ... Projecting piece, 60 ... Electric disc grinder, 63 ... Rear cover, 70 ... Commutator, 80 ... Brush, M ・ ・ Motor

Claims (3)

In a brush holder that holds a brush that is in sliding contact with a commutator attached to a rotating shaft of a motor and is fixed in a housing that houses the motor,
The brush holder is made of metal , and the brush holder is formed of a heat-resistant resin , and the brush holder is fixed in the housing with a gap between the housing and the inner surface of the housing. A brush holder, comprising: a regulating member that projects to an inner surface side and that restricts the brush holder from coming into contact with the inner surface of the housing even when the fixing of the brush holder to the housing is released . The brush holder is provided with a protruding member that protrudes toward the inner surface of the housing,
An insertion hole through which the protruding member is inserted passes through the restriction member,
2. The brush holder according to claim 1, wherein after the protruding member is inserted into the insertion hole, the protruding member is engaged with the insertion hole by bending a tip portion of the protruding member. An electric motor having a commutator attached to a rotating shaft of a motor, a brush that is in sliding contact with the commutator, a brush holder that holds the brush, and a housing that houses the motor and fixes the brush holder therein. A tool,
An electric tool, wherein the brush holder according to claim 1 or 2 is fixed in the housing.

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