JP5820753B2 - Water-powered power tool - Google Patents

Description

  According to the present invention, an air inlet for cooling air for the motor is formed in a housing that houses the motor, and a spindle that is rotated and transmitted from the output shaft of the motor is projected from the housing and attached to the spindle. A disk-shaped tool that enables polishing on the abrasive, a protective cover that is mounted on the housing and covers the disk-shaped tool, and a water injection mechanism that injects water into the polishing portion by the disk-shaped tool. It relates to water injection type electric tools.

  For example, in Patent Document 1, a disk-shaped tool that enables polishing to be polished on a spindle that is protruded from a housing is attached orthogonally, and a protective cover that covers the latter half of the disk-shaped tool is attached to the housing. The polisher which attached and formed the water injection path which injects water in the grinding | polishing process part of a to-be-polished material in the said spindle is disclosed. In the polisher of Patent Document 1, when performing surface polishing or the like on a material to be polished with a disk-shaped tool, water is injected from a water injection path to a surface polishing processing portion or the like, and with this water, dust generated by the polishing is scattered. In addition, the disk-shaped tool is cooled.

JP 2006-95667 A

  However, in the water-injected power tool including the polisher described in Patent Document 1, there is a possibility that dust generated by the polishing process may enter the housing from the motor cooling air inlet formed in the housing. In general, with this water-injection type electric tool, the motor housed in the housing is a DC motor with a brush, so if dust that has entered the housing accumulates between the brush and the commutator, the brush may be locked when the brush stops. There is. In this case, there is an inconvenience that the motor fails because electric current cannot be supplied to the rotor through the brush.

  The present invention has been proposed in view of such a situation, and an object thereof is to provide a water injection type electric tool capable of suppressing a motor failure.

The water injection type electric tool according to the first aspect of the present invention has an air inlet for cooling air of the brushless motor formed in a housing that houses the brushless motor, and is rotationally transmitted from the housing from the output shaft of the brushless motor. A disk-shaped tool that protrudes from the spindle and is attached to the spindle to enable polishing of the material to be polished, a protective cover that is attached to the housing and covers the disk-shaped tool, and polishing by the disk-shaped tool A water injection type electric tool provided with a water injection mechanism for injecting water into a part, wherein a power supply part is provided at an end of the housing, and between the brushless motor and the power supply part in the housing, A control device that is electrically connected to a power supply unit and controls the brushless motor is disposed, while the water injection mechanism includes a water supply unit that supplies water to the polishing processing unit. Pipe is provided, the water supply pipe, characterized in that it is disposed along the control device.

The invention of claim 2 is characterized in that, in claim 1 , a heat radiating plate is formed in the control device, and the water supply pipe is fixed to the heat radiating plate .

According to the water injection type electric tool according to the first aspect of the present invention, even if dust generated by polishing with a disk-shaped tool enters the housing from the air inlet formed in the housing, the brushless motor is provided with a brush. Because it is not done, brush lock does not occur. Therefore, motor failure can be suppressed by reducing the cause of motor failure (brush lock).
Further , the brushless motor control device can be positioned closer to the power supply unit than the brushless motor. Therefore, the electrical connection of the control device to the power supply unit can be efficiently performed without waste.
Furthermore , the control device can be continuously cooled by the water flowing through the water supply pipe during the polishing of the material to be polished. Therefore, the temperature rise of the control device can be suppressed.
According to invention of Claim 2 , the function which discharge | releases the heat which a control apparatus emits and the function which fixes a water supply pipe can be made to a heat sink. In addition, since the heat radiating plate can be cooled with water flowing through the water supply pipe, the heat radiating effect of the heat radiating plate can be improved.

It is a sectional side view of the water injection sander which attached the protective cover of Embodiment 1 of this invention. 3 is a plan view of a protective cover according to Embodiment 1. FIG. (A) is an exploded plan view of a cover body and an auxiliary cover constituting the protective cover, and (b) is an exploded side sectional view of the cover body and the auxiliary cover. It is a sectional side view of the water injection sander which separated the auxiliary cover from the cover body. It is the figure which showed the state which fixed the water supply pipe | tube with the heat sink of the control apparatus of the brushless motor accommodated in the inside of a water injection sander. (A) is a top view of the protective cover of Embodiment 2, (b) is a sectional side view of the protective cover. (A) is a top view of the protective cover of Embodiment 3, (b) is a sectional side view of the protective cover. (A) is a top view of the protective cover of Embodiment 4, (b) is a sectional side view of the protective cover.

<Embodiment 1>
Embodiment 1 of the present invention will be described with reference to FIGS. A water injection sander 1 shown in FIG. 1 includes a motor housing 2, a gear housing 3, a gear housing cover 4, and a protective cover 5. The water injection sander 1 is an example of the water injection type electric tool of the present invention.

  The motor housing 2 is made of resin and is formed in a cylindrical shape extending in the front-rear direction of the water injection sander 1 (left-right direction in FIG. 1). The motor housing 2 accommodates a DC brushless motor 11 (hereinafter referred to as “brushless motor 11”), a drive switch 12 for the brushless motor 11, and a control device 13 for the brushless motor. As shown in FIG. 1, the drive switch 12 and the control device 13 are disposed behind the brushless motor 11 in the motor housing 2. A slide lever 14 is provided on the outer surface of the motor housing 2 so as to be slidable in the front-rear direction. By sliding the slide lever 14, the drive switch 12 can be switched between an on state and an off state. When the drive switch 12 is on, the control device 13 controls the drive of the rotor of the brushless motor 11.

  In addition, a battery pack mounting portion 15 is provided at the rear end portion of the motor housing 2. A battery pack 16 is detachably mounted on the battery pack mounting portion 15. The battery pack 16 is electrically connected to lead wires (not shown) for supplying power to the control device 13. As shown in FIG. 1, the control device 13 is disposed in the motor housing 2 between the brushless motor 11 and the battery pack 16. As shown in FIGS. 1 and 5, on the lower surface of the control device 13, a plurality of metal (for example, aluminum) heat radiating plates 17 are provided in the left-right direction (in the left-right direction in FIG. 5) at a predetermined interval. In the vertical direction of FIG. At the lower end of each heat radiating plate 17, a protruding portion 18 that protrudes toward the heat radiating plate 17 facing each other in the left-right direction is provided. A plurality of air inlets (not shown) are formed on the left and right side surfaces of the rear portion of the motor housing 2. The battery pack 16 is an example of the power supply unit of the present invention.

  As shown in FIG. 1, in the motor housing 2, the output shaft 19 of the brushless motor 11 is rotatably supported via bearings 20 and 21. A first bevel gear 22 is provided at the tip of the output shaft 19. In addition, a cooling fan F is fixed to the outer peripheral surface of the output shaft 19.

  The gear housing 3 is made of metal (for example, aluminum) and is connected to the front (left side in FIG. 1) of the motor housing 2. An output shaft 19 projects from the motor housing 2 into the gear housing 3. A spindle 23 is supported in the gear housing 3 so as to be orthogonal to the output shaft 19 so as to be rotatable via bearings 24 and 25. A second bevel gear 26 is provided on the upper side of the spindle 23. When the first bevel gear 22 is engaged with the second bevel gear 26, the rotation of the output shaft 19 is transmitted to the spindle 23. The lower end of the spindle 23 protrudes downward from the gear housing 3 in a state of being inserted into the cylindrical portion 27 provided continuously to the lower end portion of the gear housing 3. A disc-shaped polishing tool 28 is attached to the lower end of the spindle 23 so as to be orthogonal to the spindle 23. A vent hole 29 is formed in the upper part of the front end surface of the gear housing 3 to communicate the inside and outside of the gear housing 3. The disk-shaped polishing tool 28 is an example of the disk-shaped tool of the present invention.

  As shown in FIG. 1, a gear housing cover 4 that covers an upper region of the gear housing 3 from the upper side over the entire circumference is mounted on the gear housing 3. The gear housing cover 4 is made of resin and is screwed to the left and right side surfaces of the gear housing 3. An exhaust port 30 is formed on the front end surface of the gear housing cover 4 to communicate the inside of the gear housing cover 4 with the outside.

  As shown in FIGS. 1 and 2, the protective cover 5 is formed in a dish-like shape having a circular shape in a plan view and opening downward, and covers the entire polishing tool 28 from above without contact. As shown in FIGS. 2 and 3, the protective cover 5 includes a cover body 32 and an auxiliary cover 33. The cover main body 32 is formed in a semicircular dish shape that constitutes the rear side of the protective cover 5 and opens downward. A cylindrical portion 34 made of synthetic rubber is integrally formed on the upper surface of the cover main body 32 so as to communicate with the inside of the cover main body 32 with the front half of the outer peripheral surface protruding forward from the front end of the main body cover 32. Is formed. As shown in FIG. 1, the cylindrical portion 34 is externally mounted on the cylindrical portion 27 and fastened with a band 35. In a state in which the cylindrical portion 34 is fastened to the cylindrical portion 27, the cover main body 32 covers the rear half of the polishing tool 28 (on the right side of the polishing tool 28 in FIG. 1) from above without contact, as shown.

  In addition, two engaging holes 36 and 36 are provided at the front and rear sides of the cover main body 32 at the front position of the outer peripheral surface of the cover main body 32 (the right side of the cover main body 32 in FIG. 3B). They are arranged side by side at a predetermined interval in the direction. At the rearmost position of the cover main body 32 (lower side of FIG. 3A) and in the left-right symmetrical position, drainage portions 37, 37 that communicate with the inside of the protective cover 5 and open in the left-right direction protrude. . The drains 37 and 37 are also made of synthetic rubber. Further, a synthetic resin brush 38 (see FIGS. 1 and 3B) is provided on the lower end surface of the cover body 32 over substantially the entire circumference.

  On the other hand, the auxiliary cover 33 is made of synthetic rubber like the cover main body 32 and constitutes the front side of the protective cover 5. As shown in FIG. 3A, the auxiliary cover 33 is formed in a substantially semicircular arc shape in plan view with the rear side opened. As shown in FIG. 3B, the outer peripheral surface of the auxiliary cover 33 is formed so that the amount of protrusion downward increases gradually from the rear (left side in the figure) to the front (right side in the figure). ing. Further, plate-like projecting pieces 41, 41 made of synthetic rubber are projected rearward at the rearmost positions of both ends of the auxiliary cover 33. On each protruding piece 41, positioning pins 42, 42 made of synthetic resin are fixed so as to protrude toward the inside of the auxiliary cover 33 at a predetermined interval in the front-rear direction. As shown in FIGS. 1 and 2, the positioning pins 42 and 42 are engaged with the engagement holes 36 and 36 of the cover main body 32 and are prevented from coming off. In the present embodiment, the projecting pieces 41 and 41 are restored after the positioning pins 42 and 42 are guided to the engaging holes 36 and 36 by elastically deforming the projecting pieces 41 and 41 to the outside of the auxiliary cover 33. Thus, the positioning pins 42 and 42 engage with the engaging holes 36 and 36. Further, when the cover body 32 and the auxiliary cover 33 are elastically deformed and the auxiliary cover 33 is moved forward while releasing the engagement between the positioning pins 42 and 42 and the engagement holes 36 and 36, FIG. 1 and FIG. As can be understood, the auxiliary cover 33 can be separated from the cover body 32. Each positioning pin 42 is an example of an engaging portion of the present invention, and each engaging hole 36 is an example of an engaged portion of the present invention.

  As shown in FIG. 1, when the positioning pins 42 and 42 are engaged with the engagement holes 36 and 36, the auxiliary cover 33 is integrated with the cover main body 32 and the front half of the polishing tool 28 (in FIG. 1). The outer periphery of the polishing tool 28 is covered in a non-contact manner. At this time, the auxiliary cover 33 protrudes from the cover body 32 to the tip end side in the direction X in which the spindle 23 protrudes from the gear housing 4 (lower side in FIG. 1). In addition, in the state where the cover body 32 and the auxiliary cover 33 are integrated, as shown in FIG. 2, on the front side of the protective cover 5 (upper side in FIG. 2), the inner peripheral surface of the auxiliary cover 33 and the front end of the cover body 32. An opening surrounded by the surface and the front half of the outer periphery of the cylindrical portion 34 forms a window portion 43 in which the inside can be visually recognized from the upper surface of the protective cover 5. From the window 43, the front half of the polishing tool 28 in the protective cover 5 is visible. As shown in FIG. 1 and FIG. 3B, the brush 38 is also provided on the lower end surface of the auxiliary cover 33 in the same manner as the lower end surface of the cover main body 32.

  As shown in FIG. 1, the water injection mechanism includes a water injection path 45, a water supply pipe 46, and a valve opening / closing lever 47. The water injection channel 45 is formed in the axial direction in the spindle 23 and opens at the tip surface of the spindle 23. The water supply pipe 46 is arranged in the front-rear direction (the left-right direction in FIG. 1) of the motor housing 2 below the motor housing 2 with a part thereof being fixed along the lower surface of the control device 13 in the motor housing 2. ing. As shown in FIGS. 1 and 5, in the motor housing 2, the water supply pipe 46 passes between the three sets of heat radiating plates 17, 17 opposed to each other while being locked to the protrusions 18. The front end of the water supply pipe 46 is inserted into the cylindrical portion 27 and connected to the water injection path 45. The rear end of the water supply pipe 46 is connected to a valve opening / closing lever 47 and a hose joint 48 to which a hose connected to a water pipe or the like can be attached and detached.

  Next, operation | movement of the water injection sander 1 of this embodiment is demonstrated. When chamfering a corner of the material to be polished by the water injection sander 1, the operator slides the slide lever 14 to turn on the drive switch 12. Then, the control device 13 executes control for driving the rotor of the brushless motor 11. As a result of the rotation of the brushless motor 11 being transmitted to the spindle 23 via both bevel gears 22 and 26, the polishing tool 28 rotates integrally with the spindle 23. When the cooling fan F fixed to the output shaft 19 rotates along with the rotation of the brushless motor 11, cooling air is introduced into the motor housing 2 from each intake port of the motor housing 2. The cooling air passes through the motor housing 2 to cool the brushless motor 11, and then passes through the vent hole 29 of the gear housing 3 and is discharged from the exhaust port 30 of the gear housing cover 4. The operator polishes the corner using the front half of the polishing tool 28 in a state where the motor housing 2 is supported so that the polishing tool 28 tilts backward from the horizontal posture. In this embodiment, since the window part 43 was formed in the front side of the protective cover 5, an operator grind | polished a corner | angular part, confirming the front half part of the polishing tool 28 in the protective cover 5 from the window part 43 visually. Is possible.

  At the time of polishing the corner, if the valve in the hose joint 48 is opened by operating the valve opening / closing lever 47, the water supplied by the hose is ejected from the water injection channel 45 to the polishing portion through the water supply pipe 46. The water is discharged from the drainage portions 37 and 37 along the inner surface of the protective cover 5 and the inner surfaces of the drainage portions 37 and 37. As shown in FIG. 1, the auxiliary cover 33 that forms the front side of the protective cover 5 protrudes more toward the tip end side in the protruding direction X of the spindle 23 than the cover main body 32, and thus the cover main body 32 and the auxiliary cover 33. Thus, it is possible to create a state in which the auxiliary cover 33 is brought into contact with the material to be polished after the entire polishing tool 28 is covered. For this reason, it becomes difficult to produce a gap between the material to be polished and the auxiliary cover 33. Therefore, it can suppress that the water which spouted to the grinding | polishing process part splashes outside from the front side (auxiliary cover 33) of the protective cover 5. FIG.

  On the other hand, when the flat surface of the material to be polished is polished with the water injection sander 1 of the present embodiment, the auxiliary cover 33 is separated from the cover main body 32 as shown in FIG. 32 to cover. In this state, the operator can move while rotating the polishing tool 28 against the surface of the material to be polished while keeping the spindle 23 orthogonal to the material to be polished. As a result, the surface of the material to be polished can be polished. The water sprayed to the polishing portion during the surface polishing processing takes in dust generated from the material to be polished and is discharged from the drainage portions 37 and 37.

  At the time of the chamfering process or the surface polishing process described above, the circuit components mounted on the control device 13 generate heat. Therefore, as shown in FIGS. 1, 4, and 5, if the water supply pipe 46 is fixed along the lower surface of the control device 13, the control device 13 can be continuously cooled with the water flowing through the water supply pipe 46. Therefore, the temperature rise of the control device 13 can be suppressed. In addition, the water supply pipe 46 is caused to pass between the heat radiating plates 17 and 17 facing each other in a state of being locked to the projecting portions 18, thereby causing each heat radiating plate 17 to release the heat generated by the control device 13. And the work which fixes the water supply pipe | tube 46 can be made. In addition to this, each radiator plate 17 can be cooled with water flowing through the water supply pipe 46. The control device 13 is an example of a heating element of the present invention.

  In addition, since the brushless motor 11 is used in the present embodiment, dust generated from the material to be polished may enter the motor housing 2 from each intake port together with cooling air during chamfering processing or surface polishing processing. Even if it exists, it can prevent that brush lock occurs.

<Effect of Embodiment 1>
In the water injection sander 1 equipped with the protective cover 5 and the protective cover 5 according to the present embodiment, when the corner portion of the material to be polished is chamfered, the protective cover 5 (the cover main body 32 and the auxiliary cover 33) is used for the polishing tool 28. A state in which the front side (auxiliary cover 33) of the protective cover 5 is brought into contact with the material to be polished can be created in a state of covering the whole. Therefore, since it becomes difficult to produce a clearance gap between a to-be-polished material and the said front side, it can suppress that the water spouted to the grinding | polishing process part splashes outside from the front side of the protective cover 5 during a chamfering process.

  Further, since the window portion 43 is formed on the front side of the protective cover 5, it is possible to perform chamfering using the front half portion while confirming the front half portion of the polishing tool 28 through the window portion 43.

  Further, by separating the auxiliary cover 33 from the cover main body 32, the second half of the polishing tool 28 is covered with the cover main body 32 while keeping the spindle 23 in a state orthogonal to the polishing target material, and the polishing tool 28 is covered with the polishing target material. It is possible to move while touching the surface. Therefore, the polishing tool 28 can perform the surface polishing of the material to be polished.

  In addition, in order to integrate the cover main body 32 and the auxiliary cover 33, the engagement holes 36 and 36 and the positioning pins 42 are utilized by utilizing the elastic restoring force of the cover main body 32 and the auxiliary cover 33 without using a tool. , 42 may be engaged. Therefore, the cover main body 32 and the auxiliary cover 33 can be easily integrated.

  According to the water injection sander 1 of the present embodiment, by using the brushless motor 11, dust generated by chamfering or surface polishing is temporarily introduced into the motor housing 2 together with cooling air from the air inlet formed in the motor housing 2. In case of intrusion, brush lock does not occur. Therefore, the failure of the motor can be suppressed by reducing the cause of failure (brush lock) of the motor housed in the motor housing 2.

  Further, since the control device 13 is disposed between the brushless motor 11 and the battery pack 16 in the motor housing 2, the control device 13 can be positioned closer to the battery pack 16 than the brushless motor 11. Therefore, the electrical connection of the control device 13 to the battery pack 16 can be efficiently performed without waste.

  Further, since the water supply pipe 46 is arranged along the lower surface of the control device 13, the control device 13 can be continuously cooled by the water flowing through the water supply pipe 46 at the time of chamfering or surface polishing. Therefore, the temperature rise of the control device 13 can be suppressed.

  In addition, since the water supply pipe 46 passes between the three sets of heat radiation plates 17, 17 facing each other while being locked to the respective protrusions 18, the heat generated by the control device 13 is released to each heat radiation plate 17. And a function of fixing the water supply pipe 46. In addition, since each heat sink 17 can be cooled with water flowing through the water supply pipe 46, the heat dissipation effect of each heat sink 17 can be improved.

<Embodiment 2>
A second embodiment of the present invention will be described with reference to FIG. Here, the same components as those of the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. Unlike the first embodiment, the protective cover 5A of the present embodiment has a front side and a rear side that are connected in an inseparable manner, and has a circular shape in plan view as shown in FIG. This protective cover 5A is also formed of synthetic rubber. As shown in FIG. 6B, the protective cover 5A has a dish-like shape that opens downward, and the outer peripheral surface of the protective cover 5A extends from the rear (left side of FIG. 6B) to the front (right side of FIG. 6). It is formed so that the amount of downward protrusion gradually increases as it advances. As a result, the front side of the protective cover 5A protrudes from the central portion of the protective cover 5A in the front-rear direction Y toward the tip end side (lower side in the figure) of the spindle 23 in the protruding direction X.

  Further, as shown in FIGS. 6A and 6B, a cylindrical portion 34A extending upward is integrally formed on the upper surface of the protective cover 5A so as to be concentric with the protective cover 5A and communicate with the inside of the protective cover 5A. Is formed. Further, a window portion 43 is formed on the front side of the upper surface of the protective cover 5A (the upper side in FIG. 6A).

  As in the first embodiment, the protective cover 5A of the present embodiment fastens the cylindrical portion 34A to the cylindrical portion 27 (see FIG. 1) of the water injection sander, thereby covering the entire polishing tool 28 from above without contact. . When chamfering the corner of the material to be polished by the water injection sander, the front side of the protective cover 5A protrudes to the front end side in the protruding direction X from the center portion in the front-rear direction Y of the protective cover 5A. After the protective cover 5A covers the entire polishing tool 28, it is possible to create a state in which the front side of the protective cover 5A is in contact with the material to be polished. Therefore, similarly to the first embodiment, it is possible to suppress the water spouted to the polishing portion from being scattered from the front side of the protective cover 5 to the outside.

<Effect of Embodiment 2>
In the water injection sander equipped with the protective cover 5A and the protective cover 5A of the present embodiment, when chamfering the corners of the material to be polished, the protective cover 5A is covered with the protective cover 5A covering the entire polishing tool 28. It is possible to create a state in which the front side of the substrate is in contact with the material to be polished. Therefore, since it is difficult for a gap to be generated between the material to be polished and the front side, it is possible to suppress water sprayed to the polishing portion from being scattered from the front side of the protective cover 5A to the outside during the chamfering process.

<Embodiment 3>
A third embodiment of the present invention will be described with reference to FIG. Here, the same configurations as those of the first and second embodiments are denoted by the same reference numerals, and the description thereof is omitted. As shown in FIG. 7B, the outer peripheral surface of the protective cover 5B of the present embodiment is such that the amount of downward protrusion gradually increases as it advances forward from the central portion in the front-rear direction Y of the protective cover 5B. In addition to being formed, the downward protrusion amount is gradually increased as it is moved backward from the central portion. As a result, the rear side of the protective cover 5B also protrudes from the central portion to the tip side in the protruding direction X of the spindle 23 (below (b) in FIG. 7), similarly to the front side of the protective cover 5B.

  Similarly to the protective cover 5A of the second embodiment, the protective cover 5B of the present embodiment also covers the entire polishing tool 28 from above without contact by fastening the cylindrical portion 34A to the cylindrical portion 27 of the water injection sander. When chamfering the corner of the material to be polished with the water injection sander, the protective cover 5B covers the entire polishing tool 28, and the state where the rear side of the protective cover 5B is in contact with the material to be polished is created. Can do. For this reason, it is difficult to generate a gap between the material to be polished and the rear side. Therefore, it becomes easy to receive the water which fell to the polishing process part after falling below on the said back side.

<Effect of Embodiment 3>
In the water injection sander equipped with the protective cover 5B and the protective cover 5B according to the present embodiment, a state in which the rear side of the protective cover 5B is in contact with the material to be polished can be created when chamfering the corner of the material to be polished. . Therefore, since it is difficult for a gap to be formed between the material to be polished and the rear side of the protective cover 5B, it is easy to receive water falling downward from the polishing portion on the rear side. Thereby, it can suppress that a worker splashes water at the time of a chamfering process.

<Embodiment 4>
Embodiment 4 of the present invention will be described with reference to FIG. Here, the same configurations as those in the first to third embodiments are denoted by the same reference numerals, and the description thereof is omitted. As shown in FIG. 8A, the protective cover 5C of this embodiment has an oval shape that is long in the front-rear direction Y of the protective cover 5C in plan view. In plan view, the length dimension from the center position of the cylindrical portion 34 in the front-rear direction Y to the front end of the protective cover 5C is larger than the length dimension from the center position in the front-rear direction Y to the rear end of the protective cover 5C. Increased.

  In addition, a window portion 43C is formed on the front side of the upper surface of the protective cover 5C. The window portion 43 </ b> C is formed on the upper surface in the front-rear direction Y so as to open the front side of the rear half of the outer periphery of the cylindrical portion 34 while avoiding the cylindrical portion 34. Thereby, in the top view of the protective cover 5C, in addition to the front half of the polishing tool 28, a peripheral portion adjacent to the front half can be visually recognized from the window 43C.

  The protective cover 5C of this embodiment is also attached to the water injection sander in the same manner as in Embodiments 2 and 3, and covers the entire polishing tool 28 from above without contact. When chamfering the corner of the material to be polished using the front half of the polishing tool 28 with the water injection sander, the front side of the protective cover 5C is the center of the protective cover 5C in the front-rear direction Y as in the second embodiment. Since the protective cover 5C covers the entire polishing tool 28, the state where the front side of the protective cover 5C is brought into contact with the material to be polished can be created by protruding further toward the tip side in the protruding direction X. . During this chamfering process, the operator can polish the corner while checking the front half of the polishing tool 28 and the surrounding portion adjacent thereto from the window 43C.

<Effect of Embodiment 4>
In the protective cover 5C of this embodiment and the water injection sander equipped with the protective cover 5C, the front half of the polishing tool 28 and the peripheral portion adjacent thereto are confirmed through the window 43C, and chamfering is performed using the front half. It becomes possible to do. Therefore, it becomes easy to confirm the polishing processing portion from the window portion 43, so that the work efficiency of the chamfering processing can be increased.

  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. For example, unlike the above-described embodiment, the auxiliary cover 33 may be provided with the engagement holes 36 and 36, and the positioning pins 42 and 42 to be engaged with the engagement holes 36 and 36 may be fixed to the main body cover 32. Further, instead of the engaging hole and the positioning pin, the main body cover 32 and the auxiliary cover 33 are fitted into the concave portion formed in one of the main body cover 32 and the auxiliary cover 33 with the convex portion formed in the other. And may be integrated.

  Furthermore, unlike the above-described embodiment, only one of the main body cover 32 and the auxiliary cover 33 may be formed of an elastic body such as synthetic rubber or synthetic resin. In addition, although the example which fixed the water supply pipe | tube 46 along the control apparatus 13 of the brushless motor 11 was shown in embodiment mentioned above, it is not restricted to this, For example, the electric circuit board which mounts the electrical component etc. which generate | occur | produces heat | fever By fixing the water supply pipe 46 along such a heating element, the heating element may be cooled.

  In the above-described embodiment, the motor housing 2 and the gear housing 3 are separated from each other. However, unlike this, a main body housing in which the motor housing 2 and the gear housing 3 are integrated is formed, and the main body housing is provided with the main body housing. The brushless motor 11 may be accommodated, and the lower end of the spindle 23 accommodated in the main body housing may protrude downward from the main body housing. Further, in the above-described embodiment, an example in which the present invention is applied to a rechargeable sander provided with a water injection mechanism has been shown. Or you may apply to water injection type electric tools, such as a grinder and a polisher provided with the water injection mechanism by AC drive type.

  1. Water injection sander, 2. Motor housing, 3. Gear housing, 5, 5A to 5C, protective cover, 11. Brushless motor, 13. Brushless motor control device, 16. Battery pack, 19 ..Output shaft of brushless motor, 23 ..Spindle, 28 ..Polishing tool, 32 ..Cover body, 33 ..Auxiliary cover, 36 ..Engagement hole, 42 ..Positioning pin, 43, 43 C , 45 .. water injection channel, 46 .. water supply pipe, 47 .. Valve opening / closing lever, X .. Projection direction of spindle, Y .. Front and rear direction of protective cover.

Claims (2)

An air inlet for cooling air of the brushless motor is formed in a housing that houses the brushless motor, and a spindle that is rotated and transmitted from the output shaft of the brushless motor protrudes from the housing and is attached to the spindle to be covered. A disk-shaped tool that enables polishing on the abrasive, a protective cover that is mounted on the housing and covers the disk-shaped tool, and a water injection mechanism that injects water into the polishing portion by the disk-shaped tool. A water injection type power tool,
A power supply unit is provided at an end of the housing, and a control device that controls the brushless motor by being electrically connected to the power supply unit is disposed between the brushless motor and the power supply unit in the housing. on the other hand,
The water injection mechanism is provided with a water supply pipe for supplying water to the polishing section,
The water supply type electric tool according to claim 1, wherein the water supply pipe is disposed along the control device . The water injection type electric tool according to claim 1 , wherein a heat radiating plate is formed in the control device, and the water supply pipe is fixed to the heat radiating plate .

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