JP5191726B2 - Electric tool - Google Patents

Description

  The present invention relates to an electric tool including a motor for driving a tip tool, and more particularly to a technique for fixing a brush holder.

  Japanese Utility Model Laid-Open No. 7-27274 (Patent Document 1) discloses a technique for fixing a brush holder in an electric power tool. The brush holder fixing structure described in the above publication is set by inserting the brush holder from the long axis direction between opposing reinforcing plates formed at the rear end portion in the long axis direction of the motor housing constituting the tool body, When the cover is attached to the rear end portion of the motor housing from the long axis direction, the brush holder is fixed by pressing the brush holder from the long axis direction with a pin provided on the cover. Moreover, about one brush holder among several brush holders, it is set as the structure which pushes and fixes a brush holder toward the commutator side using the rib provided in the cover.

In the above brush holder fixing structure, a reinforcing plate extending along the long axis direction is provided at the rear end portion of the motor housing in the long axis direction so as to face the motor housing, and the brush holder is mounted in a groove formed between the reinforcing plates. It is configured to be inserted and installed from the long axis direction of the housing. For this reason, it is effective in a configuration in which the end region of the motor housing is opened, that is, in a configuration in which there is no functional part in the end region of the motor housing that obstructs the mounting of the brush holder from the motor housing long axis direction. .
However, in the case where there is a functional part that obstructs the mounting of the brush holder in the long axis direction at the end of the motor housing, that is, the brush holder is inserted inward in the long axis direction from the end of the motor housing. If it is intended to be mounted in the middle region, the brush holder mounting method described in the publication is difficult to apply, and there is still room for improvement in this respect.
Japanese Utility Model Publication No. 7-27274

  According to the present invention, in an electric power tool, a brush holder can be attached to an intermediate region that extends inward in the long axis direction from an end region of the tool housing, and the brush holder is stably fixed to the intermediate region. The purpose is to provide a technology that makes it possible.

  In order to achieve the above object, a preferred form of the electric tool according to the present invention is a tool housing in which functional parts used for driving the tip tool are arranged on one end side and the other end side in the long axis direction, And a motor housed in the tool housing, and the tip tool is driven by the motor, thereby causing the tip tool to perform a predetermined machining operation. The “functional component arranged at one end” in the present invention typically includes a power switch for starting or stopping the motor, an operation lever (knob) for operating the power switch, and a motor-side terminal. Alternatively, a switch wiring mechanism unit that incorporates a switch-side terminal that can be connected to a brush corresponds to this, and as a “functional component arranged on the other end side”, typically a rotational output of a motor is applied to a tip tool. This applies to the power transmission mechanism that transmits power. In addition, the “power tool” in the present invention typically corresponds to a power tool using a motor such as a disk grinder used for grinding work or polishing work as a drive source.

According to a preferred embodiment of the present invention, the tool housing has a brush holder accommodation space in an intermediate region between one end side and the other end side in the long axis direction of the tool housing. The motor has a brush holder that is mounted by being inserted into the brush holder housing space from a direction that intersects the long axis direction of the tool housing, that is, from the outside in the radial direction. The brush holder includes a cylindrical portion that accommodates the brush, and is integrally provided with a pressed portion adjacent to the cylindrical portion. The brush holder is attached with a spring that acts to press the brush accommodated in the cylindrical portion against the commutator of the motor when the brush holder is inserted into the brush holder accommodating space. The tool housing has a cover attached to one end side in the long axis direction of the tool housing. The cover is formed in a hollow shape with one end opened, and has an inner space in the tool housing major axis direction that is continuous with the opening, and a protrusion that extends in the major axis direction of the tool housing from the opening side in the inner space. The tool housing covers one end outer surface and the intermediate region outer surface of the tool housing from the opening along the longitudinal direction of the tool housing, whereby the one end outer surface and the intermediate region outer surface of the tool housing are accommodated in the internal space. It is supposed to be configured. Then, when the cover covers the outer surface of one end of the tool housing and the outer surface of the intermediate region, the protruding portion of the inner space comes into contact with the pressed portion of the brush holder inserted into the brush holder housing space, and the brush holder is inserted in the insertion direction. That is, it was set as the structure pressed in the direction (radial direction) which cross | intersects the major axis direction of a tool housing. The term “adjacent to the cylinder part” in the present invention suitably includes both an aspect arranged directly on the outer surface of the cylinder part and an aspect arranged around the cylinder part.

According to a preferred embodiment of the present invention, the brush holder is configured to be inserted into the tool housing by inserting the brush holder in the direction intersecting the long axis direction of the tool housing, that is, from the radially outer diameter side to the inner diameter side. The brush holder can be mounted in a brush holder housing space in an intermediate region between the respective end portions in the long axis direction, that is, a region entering inward from one end portion of the tool housing. As a result, it is possible to rationalize the assembly of the brush holder to the tool housing in an electric tool having a configuration in which, for example, a switch wiring mechanism is disposed on one end side in the long axis direction of the tool housing and a power transmission mechanism is disposed on the other end side. Can be realized.
The brush holder inserted into the brush holder housing space of the tool housing includes a pressed portion, and the pressing portion is pressed in the insertion direction by the protrusion of the cover attached to one end of the tool housing from the long axis direction. It is configured. The brush holder generally has a brush biasing spring that presses a brush accommodated in a cylindrical portion of the brush holder toward the commutator. For this reason, the urging force of the urging spring is always applied to the brush holder in the direction opposite to the insertion direction, that is, in the pulling direction. Therefore, the brush holder can be stably fixed in the brush holder accommodating space.

Further, according to the present invention, one of the brush holder housing space and the brush holder is provided with a projection, and the other is provided with a recess that engages with the projection, and the brush holder is inserted into the brush holder housing space. In this case, the protrusion and the recess are engaged to hold the brush holder in the brush holder accommodating space . In addition, the engagement direction of the protrusion and the recess is set in a direction intersecting with the insertion direction of the brush holder into the brush holder accommodation space, whereby the brush holder is inserted into the brush holder accommodation space. It was set as the structure hold | maintained in the brush holder accommodation space against the reaction force produced by pressing a brush against a commutator . As described above, the urging force of the brush urging spring that presses the brush toward the commutator acts in the direction opposite to the insertion direction, that is, the removal direction, in the brush holder inserted into the brush holder housing space. . According to the present invention, since the brush holder inserted into the brush holder housing space can be held in the brush holder housing space by the engagement between the protrusion and the concave portion, when the cover is assembled to the tool housing, the operator holds the brush holder with fingers. The operation of holding the brush holder in the brush holder accommodation space becomes unnecessary, and the assembly workability of the brush holder and the cover can be improved.

  According to the further form of the electric power tool according to the present invention, when the cover is mounted so that the cover covers the outer surface of the one end portion and the intermediate region in the long axis direction of the tool housing, the protruding portion of the cover is It has a deformable tapered guide part that guides it to abut. According to the present invention, when the cover is attached to the outer surface of one end in the longitudinal direction of the tool housing and the outer surface of the intermediate region by providing the tapered guide portion on the pressed portion, the protruding portion of the cover is pressed against the pressed portion. It becomes possible to make it contact | abut reliably.

  According to the present invention, in an electric power tool, a brush holder can be attached to an intermediate region that extends inward in the long axis direction from the end region of the tool housing, and the brush holder is stably fixed to the intermediate region. The technology that made it possible to do this will be provided.

  Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. This embodiment will be described using a hand-held electric disc grinder used for grinding or polishing work of various workpieces such as metal, concrete and stone as an example of an electric tool. 1 shows the overall configuration of the electric disc grinder 101 by an external view, FIG. 2 shows the overall configuration of the electric disc grinder 101 by a sectional view, and FIG. 3 further shows the entire configuration of the electric disc grinder 101 in an exploded view. It is shown by a cross-sectional view. 4 is an enlarged view of part A in FIG. 2, FIG. 5 is an enlarged view of part B in FIG. 3, and FIG. 6 is a perspective view showing the rear cover.

  As shown in FIGS. 1 to 3, the electric disc grinder 101 generally includes a main body portion 103 that forms an outline of the electric disc grinder 101, and a grindstone 119 that is disposed in a tip region of the main body portion 103. Configured as the subject. The main body 103 is mainly composed of a motor housing 105, a gear housing 107, and a rear cover 109. The main body 103 corresponds to the “tool housing” in the present invention, and the grindstone 119 corresponds to the “tip tool” in the present invention. For convenience of explanation, the grindstone 119 side is referred to as the front and the opposite side is referred to as the rear in the major axis direction of the main body 103.

  The motor housing 105 is formed in a substantially cylindrical shape, and a drive motor 121 is accommodated in the internal space of the motor housing 105. The drive motor 121 corresponds to the “motor” in the present invention. The drive motor 121 is arranged such that the rotation axis direction electric power is in the long axis direction of the disc grinder 101, that is, the long axis direction of the main body 103. Note that the motor housing 105 constitutes a grip portion that an operator grips with one hand when the electric disc grinder 101 is operated to perform a machining operation.

  As shown in FIGS. 2 and 3, a power transmission mechanism 111 that transmits the rotational output of the drive motor 121 to the grindstone 119 is accommodated in the gear housing 107 connected to the front end portion of the motor housing 105. The power transmission mechanism 111 includes a small bevel gear 113 as a driving side gear that is rotationally driven by a drive motor 121, a large bevel gear 115 as a driven side gear that meshes and engages with the small bevel gear 113, and a spindle 117 that rotates together with the large bevel gear 115. The grindstone 119 is detachably attached to the tip of the spindle 117. The grindstone 119 is arranged on one end side (front side) of the motor housing 105 in the major axis direction (major axis direction of the main body 103) so that the rotation axis thereof is orthogonal to the rotation axis of the drive motor 121.

  The drive motor 121 in this embodiment is driven by electric power supplied from a power source (outlet) using a power cord. The drive motor 121 includes an output shaft 123, a cooling fan 124 that rotates integrally with the output shaft 123, an armature 125 that rotates integrally with the output shaft 123, a stator 127 fixed to the motor housing 105, and a rear end side of the output shaft 123. A commutator 129 provided on the opposite side of the cooling fan 124, two brushes 133 that supply current by sliding contact with the outer peripheral surface of the commutator 129, and two brush holders 131 that house the brushes 133 are mainly configured. Is done. The output shaft 123 is supported by a front bearing 126 at the front end and is supported by a rear bearing 128 at the rear end so that the output shaft 123 can rotate. The output shaft 123, the armature 125, and the commutator 129 constitute a rotor.

  A rear housing 106 is connected to the rear end of the motor housing 105. As shown in FIGS. 2 and 3, the rear housing 106 is configured so that the motor housing 105 and the stator 127 are moved in the long axis direction with the front end portion in the long axis direction fitted in the rear end opening of the motor housing 105. It is fastened together by a plurality of mounting screws 105a extending therethrough. The rear housing 106 is disposed so as to cover the commutator 129 and the rear bearing 128, and a switch wiring mechanism 151 is attached to the rear of the rear housing 106. The switch wiring mechanism 151 includes a switch block 153 made of non-conductive synthetic resin, a motor drive power switch (not shown for convenience), and an operation lever 155 (on / off operation for the power switch). In addition, although illustration is omitted for convenience, a terminal connected to a power cord for supplying current from an external power source, a terminal connected to a motor side terminal, a terminal connected to a brush 133, and the like are incorporated. Composed. In the present embodiment, the rear housing 106 is formed separately from the motor housing 105 in consideration of the assembly property of the drive motor 121 with respect to the motor housing 105, but may be formed integrally.

  The two brush holders 131 according to the present embodiment are attached to the rear housing 106. The rear housing 106 is made of non-conductive synthetic resin. Hereinafter, the structure of the brush holder 131 and the mounting structure thereof will be described mainly with reference to FIGS. 7 to 9 show the overall configuration of the brush holder, FIG. 10 is a perspective view showing the brush holder housing portion before the brush holder 131 is mounted, and FIG. The part is shown enlarged. FIG. 12 shows a process in which the brush holder is inserted into the brush holder accommodating portion, and FIG. 13 shows a state seen from the direction of arrow D in FIG. 14 shows a state in which the brush holder is inserted into the brush holder housing portion, and FIG. 15 shows a state seen from the direction of arrow E in FIG.

  As described above, in the configuration in which the switch block 153 is disposed behind the rear housing 106, it is difficult to insert the brush holder 131 from the rear of the rear housing 106 along the long axis direction. For this reason, in the present embodiment, the brush holder 131 is inserted from the direction intersecting the long axis direction of the rear housing 106 and attached to the rear housing 106. For this purpose, the rear housing 106 is formed with a radially concave brush holder housing 141 that opens outward. The brush holder accommodating portion 141 corresponds to the “brush holder accommodating space” in the present invention. As shown in FIG. 3, two brush holder accommodating portions 141 are set in a region facing the commutator 129 at a predetermined interval (180 degrees in the present embodiment) in the circumferential direction. A region facing the commutator 129 in the rear housing 106 corresponds to an “intermediate region” in the present invention.

  As shown in FIG. 3, each brush holder 131 is mounted by being inserted into the brush holder accommodating portion 141 from the direction intersecting the long axis direction of the rear housing 106, that is, from the radial direction. 7 to 9 show the overall configuration of the brush holder 131. FIG. The brush holder 131 is formed in a predetermined shape by processing a conductive metal plate. The brush holder 131 is integrally formed with a cylindrical portion 132 having a substantially rectangular cross section for accommodating the brush 133. The cylindrical portion 132 extends in the insertion direction of the brush holder 131, and as shown in FIG. 4, when the brush holder 131 is inserted into the brush holder accommodating portion 141, the cylindrical hole is in the brush holder accommodating portion 141. It arrange | positions so that it may face the opening 141a formed in the wall surface. A brush 133 is slidably accommodated in the cylindrical portion 132. The brush 133 is brought into contact with the outer peripheral surface of the commutator 129 through the opening 141a at a substantially right angle from the radial direction, and is attached to the brush holder 131. The spiral spring 134 is slidably pressed against the outer peripheral surface of the commutator 129. The spiral spring 134 is a brush biasing spring, one end of which is fixed to the locking piece 131a of the brush holder 131, and the other end is biased toward the commutator 129 when viewed from the brush holder insertion direction. .

  Further, the brush holder 131 is integrally provided with two insertion pieces 135a and 135b that are formed to face each other on one end side in a direction (housing major axis direction) intersecting the tube hole direction of the tube portion 132. Yes. The insertion piece 135a on one side (upper side in FIGS. 7 and 8) is formed in a substantially inverted U shape when viewed from the insertion direction, and the insertion piece 135b on the other side (lower side in FIGS. 7 and 8) It is formed in a substantially L shape from the direction. These two insertion pieces 135a and 135b are inserted into correspondingly shaped slits 142a and 142b formed in the brush holder accommodating portion 141 shown in FIG. 10 and FIG. It is arranged at a predetermined position. Each of the slits 142a and 142b is formed by a plurality of plate-like members 143 that are formed to face each other at a predetermined interval in the brush holder accommodating portion 141.

  Further, a hemispherical protrusion 137 is integrally formed on each of the insertion pieces 135a and 135b (see FIG. 13). When the insertion pieces 135a and 135b are inserted into the slits 142a and 142b, the protrusion 137 engages with a hemispherical recess (or groove) 144 (see FIGS. 11 and 13) formed in the plate-like member 143. As a result, the brush holder 131 is held at a predetermined position of the brush holder accommodating portion 141 (see FIGS. 14 and 15). When the brush holder 131 is inserted into the brush holder housing 141 and the brush 133 is pressed against the outer peripheral surface of the commutator 129, the brush holder 131 is provided with a spiral spring 134 that urges the brush 133 to press against the commutator 129. The force acts as a reaction force in the direction opposite to the insertion direction, that is, in the withdrawal direction. However, the engagement between the protrusion 137 and the recess 144 allows the brush holder 131 to be held at a predetermined position against the reaction force acting on the brush holder 131.

  Further, the brush holder 131 disposed in the brush holder accommodating portion 141 is configured to be pressed and fixed from the back side in the insertion direction by a rear cover 109 mounted so as to cover the rear housing 106 (see FIG. 4). . The rear cover 109 corresponds to a “cover” in the present invention. As shown in FIG. 6, the rear cover 109 is formed in a substantially cylindrical shape with one end (front end) opened, and two ribs 145 extending in the major axis direction on the inner wall surface 109a of the cylinder hole. Are integrally formed at intervals of 180 degrees in the circumferential direction. The rib 145 also functions as a reinforcing member. The cylindrical hole corresponds to the “internal space” in the present invention, and the rib 145 corresponds to the “ridge portion” in the present invention. When the rear cover 109 is mounted so as to cover the rear housing 106 from the long axis direction of the rear housing 106, the rib 145 presses the protruding piece 139 formed on each brush holder 131 from the back side in the insertion direction (FIG. 4 and FIG. 4). (See the two-dot chain line in FIG. 9). Thereby, the brush holder 131 is firmly fixed in a state in which the brush holder 131 is prevented from being detached from the brush holder accommodating portion 141. The projecting piece 139 corresponds to the “pressed portion” in the present invention. The protruding piece 139 is integrally formed on the back side in the insertion direction of one insertion piece 135 a adjacent to the cylindrical portion 132.

  Further, the projecting piece 139 projects in an inclined manner with respect to the covering direction of the rear cover 109 (mounting direction) and can be deformed. As a result, the end of the rib 145 is guided so as to come into contact with the protruding piece 139. The protruding piece 139 protrudes in an inclined shape, thereby forming the “tapered guiding portion” in the present invention.

  The rear cover 109 that covers the rear housing 106 has an opening end fitted to the outer periphery of the front end of the rear housing 106, and is fastened to the rear housing 106 by a fastening screw 147 in the fitted state (FIG. 2). reference). Thus, the rear housing 106, the brush holder 131 and the switch block 153 are accommodated in the rear cover 109. As shown in FIG. 1, the operation lever 155 assembled to the switch block 153 protrudes outside through an opening (not shown for convenience) formed in the rear end portion of the rear cover 109 so that the operator can operate it. It is possible. Therefore, the operator grips the motor housing 105 and energizes the drive motor 121 through the operation of the operation lever 155 to rotationally drive the grindstone 119 through the power transmission mechanism 111, so that the workpiece Grinding and polishing operations or cutting operations can be performed as appropriate.

  In the present embodiment, the brush holder 131 is mounted by being inserted into the brush holder accommodating portion 141 of the rear housing 106 from the long axis direction of the rear housing 106, that is, the direction intersecting the long axis direction of the main body portion 103. . For this reason, in the housing structure in which the switch wiring mechanism 151 is disposed at the rear end of the rear housing 106 and the brush holder 131 is prevented from being mounted from the rear to the front of the rear housing 106, The brush holder 131 can be reasonably assembled to the middle region in the long axis direction.

  According to the present embodiment, the rib 145 of the rear cover 109 attached to the rear housing 106 from the long axis direction contacts the protruding piece 139 of the brush holder 131 and presses it in the insertion direction of the brush holder 131. The configuration is fixed. For this reason, the brush holder 131 can be stably fixed in a state in which the brush holder 131 is prevented from being detached from the brush holder accommodating portion 141. Further, the projecting piece 139 protrudes in an inclined manner with respect to the mounting direction of the rear cover 109 and can be deformed. Can be worn while absorbing.

  In the present embodiment, the insertion pieces 135a and 135b of the brush holder 131 are inserted into the slits 142a and 142b while being guided by the plate-like member 143 that forms the slits 142a and 142b of the brush holder accommodating portion 141. The insertion work of the brush holder 131 into the brush holder accommodating portion 141 can be easily performed.

  Further, when the brush holder 131 is inserted into the brush holder accommodating portion 141, the protrusions 137 provided on the insertion pieces 135a and 135b engage with the concave portion 144 on the brush holder accommodating portion 141 side. As a result, the brush holder 131 is held at a predetermined position against the biasing force of the spiral spring 134 that biases the brush 133. Therefore, when attaching the rear cover 109 to the rear housing 106, the operator does not need to hold the brush holder 131 in the brush holder housing 141 with his / her fingers, and the workability of assembling the brush holder 131 and the rear cover 109 can be improved. it can.

  In the present embodiment, the electric disc grinder 101 has been described as an example of the electric tool. However, the rear end of the rear housing 106 includes the brush holder 131 at the rear end of the rear housing 106 at the rear end of the rear housing 106. Any power tool can be used as long as it has a member that obstructs the mounting method facing forward.

1 is an external view showing an overall configuration of an electric disc grinder according to an embodiment of the present invention. It is sectional drawing which shows the whole structure of an electric disc grinder. It is an exploded sectional view showing the whole composition of an electric disc grinder. It is the A section enlarged view of FIG. It is the B section enlarged view of FIG. It is a perspective view which shows a rear cover. It is a perspective view which shows the structure of a brush holder. It is a perspective view which similarly shows the structure of a brush holder. It is a side view which similarly shows the structure of a brush holder. It is a perspective view which shows the brush holder accommodating part before a brush holder is inserted. It is the C section enlarged view of FIG. It is a figure which shows the process in which a brush holder is inserted in a brush holder accommodating part. It is D arrow line view of FIG. It is a figure which shows the state by which the brush holder was inserted in the brush holder accommodating part. It is E arrow line view of FIG.

101 Electric disc grinder (Electric tool)
103 Main body (tool housing)
105 Motor housing 105a Mounting screw 106 Rear housing 107 Gear housing 109 Rear cover (cover)
109a Tube hole inner wall surface 111 Power transmission mechanism 113 Small bevel gear 115 Large bevel gear 117 Spindle 119 Grinding wheel (tip tool)
121 Drive motor
123 Output shaft 124 Cooling fan 125 Armature 126 Bearing 127 Stator 128 Bearing 129 Commutator 131 Brush holder 132 Tube part 133 Brush 134 Spiral spring 135a, 135b Insertion piece 137 Projection part 139 Projection piece (Pressed part)
141 Brush holder housing (brush holder housing space)
141a Openings 142a, 142b Slit 143 Plate-like part 144 Recessed part 145 Rib (projection part)
147 Fixing screw 151 Switch wiring mechanism 153 Switch block 155 Operation lever

Claims (2)

A functional housing used for driving the tip tool is disposed on each of one end side and the other end side in the long axis direction;
A motor housed in the tool housing,
An electric tool that drives the tip tool by the motor, thereby causing the tip tool to perform a predetermined machining operation,
The tool housing has a brush holder accommodating space in an intermediate region between one end side and the other end side in the long axis direction,
The motor has a brush holder that is attached by being inserted into the brush holder housing space from a direction that intersects the long axis direction of the tool housing,
The brush holder has a cylindrical portion that accommodates the brush, and is integrally provided with a pressed portion adjacent to the cylindrical portion,
The brush holder is attached with a spring that acts to press the brush accommodated in the cylinder portion against the commutator of the motor when the brush holder is inserted into the brush holder accommodating space.
The tool housing has a cover attached to one end side in the long axis direction of the tool housing,
The cover is formed in a hollow shape with one end opened, and has an inner space in the tool housing long axis direction that extends to the opening, and the inner space extends from the opening side in the long axis direction of the tool housing. And has one end outer surface and an intermediate region outer surface of the tool housing covering from the opening along the longitudinal direction of the tool housing, whereby the one end outer surface and the intermediate region outer surface are in the internal space. It is configured to be accommodated,
The protruding portion is configured to contact the pressed portion of the brush holder inserted into the brush holder accommodating space and press the brush holder in the insertion direction intersecting the long axis direction of the tool housing ,
One of the brush holder accommodation space and the brush holder is provided with a protrusion, and the other is provided with a recess that engages with the protrusion, and when the brush holder is inserted into the brush holder accommodation space, A configuration in which a protrusion and the recess are engaged and the brush holder is held in the brush holder accommodating space,
The engagement direction of the protrusion and the recess is set in a direction intersecting with the insertion direction of the brush holder into the brush holder accommodation space, whereby the brush holder is inserted into the brush holder accommodation space. The power tool, wherein the spring is held in the brush holder accommodating space against a reaction force generated by the spring pressing the brush against the commutator in a state . The electric tool according to claim 1 ,
The pressed portion is a deformable tapered guiding portion that guides the protruding portion of the cover to contact when the cover is mounted so as to cover the outer surface of one end portion and the intermediate region of the tool housing. A power tool characterized by comprising:

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