JP6874481B2 - Electric tool - Google Patents

Description

The present invention relates to a power tool such as a grinder.

Japanese Unexamined Patent Publication No. 2010-036281

The prior art document has a slide switch (knob) provided in the grip portion of the housing, and by operating the slide switch, a grinder that operates a snap switch arranged on one end side of the motor to turn the motor on and off. Is described. Since the slide switch is provided on the side surface of the housing located around the motor, when the operator grips the housing around the motor and works, the slide switch can be operated while holding the housing, and the configuration is rich in operability. It has become. The snap switch has a lever and turns on / off the power supply to the motor according to the operating position of the lever. Since the snap switch requires a smaller load when it is turned on and off than the push-type push switch, the force required to operate the slide switch can be reduced. Also, unlike the push switch, the switch itself does not have a restoring force, so the force to hold the slide switch when keeping the motor on can be minimized. Therefore, in the grinder described in the prior art document, the slide switch can be easily operated even while holding the housing. On the other hand, in recent years, as it has become possible to miniaturize motors due to high efficiency, tools such as grinders are required to be miniaturized. However, when the grinder housing described in the prior art document is miniaturized, a space for accommodating snap switches arranged along the longitudinal direction in the left-right direction is provided so that the lever projects in the slide switch direction. Since it is necessary to secure the tool body, it may be difficult to miniaturize the tool body.

The present invention has been made in recognition of such a situation, and an object of the present invention is to provide a power tool capable of realizing miniaturization even by using a snap switch.

One aspect of the present invention is a power tool. The power tool is supported by a motor, a housing that accommodates the motor and extends in the front-rear direction, a switch that is provided behind the motor in the housing and switches between driving and stopping the motor, and the housing. It has an operation unit that can slide back and forth with at least a part exposed on the surface of the housing located on the left side of the motor, and a slide bar that extends in the front-rear direction and transmits the operation of the operation unit to the switch. The switch has a lever for switching the energization of the motor according to the swing position and a main body for supporting the lever, and the switch has a left-right direction and a protrusion direction of the lever from the main body. as a direction intersecting the both front-back direction, is supported by the front Symbol housing such that the longitudinal direction of the switch in the back-and-forth direction as viewed inclined to the horizontal direction, an end portion of said lever, said The slide bar is at a position different from the center position of the operation unit in the rotation direction of the motor, and the slide bar is at a position different from the center position of the operation unit in the rotation direction of the motor and engages with the end of the lever. Has an engaging portion to engage.

The switch has a main body portion that supports the lever, and the lever may be engaged with the slide bar by projecting from the main body portion in a direction inclined by a predetermined angle with respect to the left-right direction.

The rear end of the slide bar may be provided with a curved portion that curves along the inner surface of the housing, and the lever may be engaged with the curved portion.

A through hole may be provided in the curved portion, and the lever and the through hole may be engaged so as to overlap each other in the front-rear direction.

The housing has intake ports provided on the left and right side surfaces behind the motor and exhaust ports provided in front of the motor, and a fan rotated by the motor is housed in the housing. An air flow is generated in the housing by the rotation of the fan, and the switch may be arranged upstream of the motor in the air flow.

The switch may be held in the housing by a slope portion extending in a direction inclined with respect to the left-right direction and a protrusion extending in a direction substantially orthogonal to the extending direction of the slope portion.

Any combination of the above components and a conversion of the expression of the present invention between methods, systems and the like are also effective as aspects of the present invention.

According to the present invention, it is possible to improve the operability and reduce the size of the power tool.

FIG. 3 is a plan sectional view of the grinder 1 according to the first embodiment of the present invention. The cross-sectional view on the left side. A cross-sectional view taken along the line AA of FIG. BB sectional view of FIG.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. The same or equivalent components, members, etc. shown in the drawings are designated by the same reference numerals, and redundant description will be omitted as appropriate. Moreover, the embodiment is not limited to the invention but is an example, and all the features and combinations thereof described in the embodiment are not necessarily essential to the invention.

The grinder 1 according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 4. Each direction is defined by the arrows shown in FIGS. 1 to 3, and the explanation is given according to the defined direction.

As shown in FIGS. 1 and 2, the grinder 1 of the present embodiment includes a grindstone 10 as a tip tool (rotating tool), and is used for grinding work for flattening the surface of concrete, stone, or the like. The grindstone 10 has a disk shape and a diameter of, for example, 100 mm to 250 mm. As the tip tool, in addition to a disc-shaped polishing grindstone and a cutting grindstone, a disc-shaped brush, a cutter, or the like can also be attached. The grinder 1 includes a motor housing 2, a tail cover 3, and a gear case 4. The motor housing 2 and the tail cover 3 correspond to the housing of the present invention. Hereinafter, the entire combination of the motor housing 2 and the tail cover 3 is also referred to as a “housing”.

The motor housing 2 and the tail cover 3 are made of, for example, resin, and form an outer frame having a substantially cylindrical shape as a whole. A motor (electric motor) 6 and a fan 5 are housed inside the motor housing 2. The motor 6 is a brushed motor (commutator motor) in the present embodiment, and is connected to an external AC power source such as a commercial power source via a power cord 7 drawn from the rear end of the motor housing 2. As shown in FIG. 2, external brush units 6c are provided on the left and right side surfaces of the housing, respectively. The brush unit 6c is an example of a control member for motor drive control. The brush unit 6c includes a brush 6d, a brush cap 6e, and a brush holder 6f that come into contact with the commutator 6b of the motor 6. By removing the brush cap 6e, the brush 6d can be replaced without disassembling the motor housing 2 and the tail cover 3. Such a feature that the housing can be replaced without disassembling the housing (without removing the tail cover 3 from the motor housing 2) is called an exterior type. The brush unit of the type in which the housing is disassembled and replaced is called an internal type. The fan 5 is rotatably provided in front of the motor 6 on the output shaft 6a of the motor 6. The fan 5 is covered with a fan guide 8. The bearing holder 9 is sandwiched between the motor housing 2 and the gear case 4 and is located in front of the fan 5. The front end of the output shaft 6a of the motor 6 extends into the gear case 4 and is provided with the first bevel gear 21.

A switch 70 held by the motor housing 2 is provided in the tail cover 3. The switch 70 switches whether or not the motor 6 is energized (driving and stopping the motor 6), and is provided behind the motor 6. On the other hand, on the front left side surface of the motor housing 2, an operation unit 60 that can be slid in the front-rear direction for an operator to operate the switch 70 is provided. Inside the motor housing 2, a slide bar 50 that extends in the slide direction of the operation unit 60 and transmits the operation of the operation unit 60 to the switch 70 is provided. The slide operation of the operation unit 60 by the operator is transmitted to the switch 70 by the slide bar 50, and the switch 70 is switched on and off. The details of the configuration in which the switch 70 is operated by the operation unit 60 will be described later. In the present embodiment, the state in which the operation unit 60 is slid forward corresponds to the on of the switch 70, and the state in which the operation unit 60 is slid backward corresponds to the off of the switch 70. Although the slide bar 50 is urged rearward by the spring 61, the operation unit 60 can be locked at a position where the switch 70 is turned on by the uneven engagement with the motor housing 2.

The gear case 4 is made of a metal such as an aluminum alloy and is attached to the front end portion of the motor housing 2. The opening of the gear case 4 is closed by the packing land 11 as a lid member. The packing land 11 is fixed to the gear case 4 by, for example, screwing. The packing land 11 is a holding member that holds the foil guard 30, which will be described later. Two bearings (needle bearing 12 and ball bearing 13) are provided inside the gear case 4, and the spindle 20 is rotatably held by these bearings. The spindle 20 is substantially orthogonal to the output shaft 6a (rotor rotation shaft) of the motor 6, and one end thereof penetrates the packing land 11 and projects to the outside. On the other hand, at the other end of the spindle 20 located in the gear case 4, a second bevel gear 22 that meshes with the first bevel gear 21 attached to the output shaft 6a of the motor 6 is provided. The rotation of the motor 6 is transmitted to the spindle 20 by reducing the rotation speed by 90 degrees while the rotation direction is changed by 90 degrees by the first bevel gear 21 and the second bevel gear 22 as reduction portions. That is, the spindle 20 is rotationally driven by the motor 6.

The grindstone 10 is fixed to the spindle 20 by a foil washer and a locknut, and rotates integrally with the spindle 20. When the operation unit 60 provided in the motor housing 2 is operated and the switch 70 is turned on, electric power is supplied to the motor 6 and the output shaft 6a of the motor 6 rotates. Then, the spindle 20 connected to the output shaft 6a via the first bevel gear 21 and the second bevel gear 22 rotates, and the grindstone 10 fixed to the spindle 20 rotates. A foil guard 30 that covers at least 1/2 or more of the outer circumference of the grindstone 10 is attached to the packing land 11. The wheel guard 30 is detented so that its rotation position does not change during work, and the rotation position can be changed according to the work content by releasing the detent.

The slide bar 50 includes a base 51 that engages the operating portion 60 and a lever engaging portion 52 that engages the switch 70. The base 51 is located in the front-rear direction overlapping the motor 6, and is arranged close to the inner surface of the motor housing 2 as shown in FIG. The brush unit 6c is located between the base 51 and the lever engaging portion 52.

FIG. 4 is a cross-sectional view taken along the line BB shown in FIG. As shown in FIG. 4, the outer peripheral surface of the stator core 6h of the motor 6 has a flat surface portion 6i whose left and right facing surfaces (the surface on the side where the slide bar 50 exists and the opposite surface). Therefore, the dimension (width across flats) of the motor 6 in the left-right direction is shorter than the dimension in the up-down direction, and the slide bar 50 is placed in the space between the left side surface of the motor 6 and the inner surface of the motor housing 2 formed thereby. It is postponed. A stator coil 6j is wound around each of the left and right winding slots of the stator core 6h. The gaps 6k between the stator poles are located above and below the rotor 6g, respectively.

Next, the switch 70, which is a feature of the present invention, and its peripheral structure will be described in detail. The switch 70 is a snap switch having a lever 71 and a main body 72. The lever 71 is swingably supported with respect to the main body 72. In this embodiment, power is supplied to the motor 6 when the lever 72 swings forward, and the motor 6 swings backward when the lever 72 swings backward. Cut off the power supply to. Note that FIGS. 1 to 3 show a state in which the power supply to the motor 6 is cut off, that is, a state in which the motor 6 is off. The main body 72 has a substantially cubic shape, and has an upper surface 72a on which the lever 71 protrudes, a bottom surface 72b which is an opposite side surface of the upper surface 72a, a front surface 72c facing the front, and a rear surface facing the rear. It has a total of six side surfaces, 72d, a right surface 72e facing the right side (strictly speaking, the upper right direction), and a left surface 72f facing the left side (strictly speaking, the lower left direction). A terminal 73 for electrical connection is provided on the bottom surface 72b. The electric power from the power cord 7 is supplied to the motor 6 via the switch 70 by wiring or the like connected to the terminal 73.

FIG. 3 is a cross-sectional view taken along the line AA in FIG. The switch 70 is held by a switch holding portion 25 formed at the rear end of the motor housing 2 and entering the tail cover 3. In FIG. 3, the switch holding portion 25 is a slope portion 25a extending in a direction inclined by a predetermined angle α with respect to the left-right direction (direction from the upper left to the lower right), and the slope portion 25a from the end portion of the slope portion 25a. It has a protrusion 25b extending in a direction orthogonal to the extending direction. In this embodiment, the predetermined angle α is 15 °.

The switch 70 is arranged so that the bottom surface 72b is in contact with the protrusion 25b while the left surface 72f is in contact with the slope portion 25a. If the switch 70 is to be held only by the slope portion 25a, the switch 70 may move along the extending direction of the slope portion 25a, but two portions extending in different directions (slope portion 25a and protrusion 25b) ) Holds the switch 70, so that the position of the switch 70 can be suitably positioned. Then, the switch 70 is fixed to the switch holding portion 25 by using a fixing tool such as a screw (not shown) while being held by the slope portion 25a and the protrusion 25b. The longitudinal dimension of the switch 70 (from the tip of the lever 71 to the end of the terminal 73) is indicated by L in the figure. The center of the switch 70 in the longitudinal direction is arranged so as to be substantially located on the rotation center axis C of the output shaft 6a. This makes it possible to form the tail cover 3 in a small size.

Next, the on / off structure of the switch 70 will be described. The operation unit 60 that can be operated by the operator is provided on the left side surface of the motor housing 2, and when the motor housing 2 is gripped and operated, the operation unit 60 is located at the gripping position, so that the gripping method is not changed. The motor 6 can be turned on and off. A slide bar 50 is engaged with the operation unit 60, and moves back and forth in conjunction with the front-back movement of the operation unit 60. The slide bar 50 has a base portion 51 that engages with the operating portion 60, and a lever engaging portion 52 that is formed at the rear end and engages with the lever 71. The base portion 51 and the lever engaging portion 52 are integrally formed. The lever engaging portion 52 has a curved portion 52A that curves along the inner peripheral surface of the tail cover 3, and the curved portion 52A is provided with a through hole 52B. The lever 71 engages with the slide bar 50 by being located in the through hole 52B, and the forward / backward movement of the slide bar 51 is transmitted to the lever 71 by the inner wall surface of the through hole 52B, and the on / off of the switch 70 is operated. As shown in FIG. 3, the curved portion 52, the through hole 52B, and the lever 71 are located so as to overlap each other in the axis C direction.

Next, the dimensions around the switch 70 will be described with reference to FIG. In FIG. 3, the total length of the switch 70 is shown by L, the vertical inner diameter of the tail cover 3 is shown by L1, and the horizontal inner diameter of the tail cover 3 is shown by L2. The magnitude relationship of these dimensions is L1> L> L2. In this way, the tail cover 3 is formed to have an elliptical outer diameter by making the dimensions in the vertical direction larger than those in the horizontal direction. By forming the tail cover 3 in such an elliptical shape, it is possible to form a shape that is easy to grip when the spindle 20 is gripped from above in a state of protruding downward as shown in FIG. Further, since the switch 70 is arranged so as to be inclined in the longitudinal direction (indicated by S in FIG. 3) with respect to the left-right direction, L2 can be formed smaller than L, and the tail cover 3 can be made small and easy to grip. Can be done.

Next, the wind window 3A provided on the tail cover 3 will be described. In order to make the grinder 1 easy to grip, the motor housing 2 and the tail cover 3 have a substantially cylindrical shape, and a spindle is provided by a grindstone 10 that spreads forward, backward, left and right, and a wheel guard 30 that covers the grindstone 10. It is difficult to place the 20 in a state where it protrudes left and right or upward. On the other hand, since the foil guard 30 is provided with a flat surface portion, it is easy to place the foil guard 30 in a state of being in contact with the ground. Therefore, it is often placed on the ground or the like in the orientation as shown in FIG. 2, but if a wind window is provided on the upper surface of the tail cover 3 at this time, dust or the like falling from above will enter the tail cover 3. There is a fear. Further, when the wind window is provided on the lower surface of the tail cover 3, the wind window faces the work area (grinding stone 10), so that iron powder or the like generated on the lower side of the tail cover 3 during work enters the tail cover 3 from the wind window. It becomes easy to be sucked. Therefore, in the grinder 1, it is preferable that the wind windows functioning as the intake ports are provided on the left and right or both housing side surfaces, so that the wind windows 3A are provided on the left and right side surfaces of the tail cover 3. In order to secure the amount of air, the wind window 3A is opened to a position behind the switch 70.

The air sucked into the tail cover 3 from the wind window 3A enters the motor housing 2 from the tail cover 3 in order to cool the electronic components such as the motor, cools the motor 6, and then the exhaust port 4A provided in the gear case 4. Is discharged from. At this time, since the switch 70 is arranged so as to incline the longitudinal direction with respect to the opening direction (left-right direction) of the wind window 3A, it does not obstruct the flow of air entering from the left and right. Further, since the terminal 73 can be moved away from the wind window 3A by inclining the switch 70, the insulation performance can be improved by increasing the distance from the housing surface to the electronic component.

As described above, according to the configuration of this embodiment, the following effects are obtained.

(1) In the grinder 1, the switch 70 can be turned on and off without changing the grip during work by providing the sliding operation unit 60 in front of the left side surface of the housing (outer peripheral side of the motor 6). Where the lever 71 must be positioned on the left side in order to engage the slide bar 50 arranged on the left side with the lever 71 of the switch 70, the longitudinal direction of the switch 70 is the extending direction (vertical direction) of the spindle 20 and the axis line. Since it is tilted in the direction (left-right direction) orthogonal to each of the C direction (front-back direction), it is possible to reduce the size of the housing in the left-right direction, making it easy to grip and easy to work with. can do.

(2) Since the rear end of the slide bar 50 is provided with a curved portion 52A that curves and extends along the inner peripheral surface of the housing, the housing 2 is not enlarged and is inclined in the left-right direction. The protruding lever 71 and the slide bar 50 can be engaged with each other.

(3) Since the through hole 52B is provided in the curved portion 52A and the lever 71 and the through hole 52B are engaged so as to overlap each other in the direction of the axis C, the inner surface of the tail cover 3 can be brought close to the vicinity of the lever 71. , The housing can be miniaturized.

(4) A configuration in which air windows 3A that function as an intake port are provided on the left and right sides of the housing at a position that overlaps the switch 70 in the front-rear direction (a position that overlaps the switch 70 in the left-right direction) or at a position behind the switch 70. Since the switch 70 is tilted in the left-right direction, the switch 70 (particularly the lever 71 and the terminal 73) arranged on the upstream side of the motor 6 in the air flow entering from the wind window 3A and exiting forward is housed. Since it does not obstruct the flow of air inside, it is possible to generate cooling air with less turbulence in the housing.

(5) Since the switch 70 is held (temporarily fixed) on the slope portion 25a and the protrusion 25b, the switch 70 can be easily fixed at the time of assembly even if the longitudinal direction of the switch 70 is tilted with respect to the left-right direction. it can.

Although the present invention has been described above by taking the embodiment as an example, it is understood by those skilled in the art that each component of the embodiment can be variously modified within the scope of the claims.

1,1A grinder, 2 motor housing, 2A body housing, 2b rib, 2c guide member, 3 tail cover, 3b, 3c intake port, 4 gear case, 4a exhaust port, 5 fan, 6 motor (electric motor), 6a output shaft , 6b commutator, 6c brush unit, 6d brush, 6e brush cap, 6f brush holder, 6g rotor, 6h stator core, 7 power cord, 8 fan guide, 9 bearing holder,
10 grindstone, 11 packing land, 12 needle bearing, 13 ball bearing, 20 spindle, 21 first bevel gear, 22 second bevel gear, 30 wheel guard, 50 slide bar, 51 base, 52 lever engagement part, 52A curved part , 52B through hole, 60 operation part, 61 spring, 70 switch, 71 lever,

Claims (6)

With the motor
A housing that houses the motor and extends in the front-rear direction,
A switch provided behind the motor in the housing to switch between driving and stopping the motor,
An operating unit that is supported by the housing and can slide back and forth with at least a part exposed on the surface of the housing located on the left side of the motor.
It has a slide bar that extends in the front-rear direction and transmits the operation of the operation unit to the switch.
The switch has a lever that switches the energization of the motor according to the swing position, and a main body that supports the lever.
In the switch, the longitudinal direction of the switch is tilted with respect to the left-right direction in the front-rear direction view so that the protruding direction of the lever from the main body portion intersects both the left-right direction and the front-back direction. is supported by the front Symbol housing for,
The end of the lever is located at a position different from the center position of the operation unit in the rotation direction of the motor.
The slide bar is an electric tool having an engaging portion that is located at a position different from the center position of the operating portion in the rotation direction of the motor and engages with the end portion of the lever. The power tool according to claim 1, wherein the housing is provided with a switch accommodating portion for accommodating the switch, and the size of the switch accommodating portion in the left-right direction is smaller than the size in the up-down direction. The power tool according to claim 2, wherein the engaging portion is provided at the rear end of the slide bar and is curved along the inner surface of the housing. The power tool according to claim 3, wherein a through hole is provided in the engaging portion, and the lever and the through hole are engaged so as to overlap each other in the front-rear direction. The housing has an intake port provided on the left and right side surfaces behind the motor and an exhaust port provided on the front side of the motor.
A fan rotated by the motor is housed in the housing.
An air flow is generated in the housing by the rotation of the fan.
The electric motor according to claim 4, wherein at least a part of the switch is located on an extension line of the rotation shaft of the motor and is arranged upstream of the motor in the air flow. tool. The housing is provided with a slope portion extending in a direction inclined with respect to the left-right direction and a protrusion extending in a direction substantially orthogonal to the extending direction of the slope portion.
The power tool according to any one of claims 1 to 4, wherein the switch is held in the housing by the slope portion and the protrusion.

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