Power tool

Abstract

To effectively prevent short circuit by imparting high sealability to an electrical connection part between a controller and a switch.SOLUTION: A grinder 1 comprises in a rear cover 4: a motor 6; a controller 9 which has a circuit board 86 and a controller side terminal 97 electrically connected with the circuit board 86; and a switch 8 which has a switch side terminal 67 electrically connected with the controller side terminal 97. The controller side terminal 97 is arranged on a top face 9a of the controller 9, and the switch side terminal 67 is arranged under an underside 8a of the switch 8 so that the controller side terminal 97 directly contacts with the switch side terminal 67 to be electrically connected with each other. An elastic sheet 100 is arranged between the top face 9a of the controller 9 and the underside 8a of the switch 8 to seal, while the controller side terminal 97 directly contacts with the switch side terminal 67, the periphery of both terminals 97, 67.SELECTED DRAWING: Figure 11

Description

Technical Field

[0001] The present disclosure relates to power tools such as grinders.

Background Art

[0002] In power tools such as grinders, as disclosed in Patent Document 1, a controller and a switch for turning the motor on / off are housed in a housing, and the controller and the switch are electrically connected. Patent Document 1 discloses an invention of a grinder in which a switch block having a switch is assembled to a housing, a male terminal is housed in the controller, a female terminal is housed in the switch block, and a connection portion having an inlet for the male terminal is formed. Along with the assembly of the switch block and the controller, the male terminal is inserted and connected to the female terminal. In particular, here, a blocking portion is provided on the male terminal side to cover the formation surface of the inlet in the connection portion in the inserted connection state of the male terminal, thereby imparting dust-proofness to the connection portion.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above conventional power tool, since the blocking portion is made of resin, it is difficult to ensure high sealing performance even when covering the formation surface of the inlet of the male terminal, and there is a risk of allowing intrusion of iron powder or the like and causing a short circuit.

[0005] Therefore, an object of the present disclosure is to provide a power tool capable of imparting high sealing performance to the electrical connection portion between the controller and the switch and effectively preventing a short circuit.

Means for Solving the Problems

[0006] In order to achieve the above object, the present disclosure provides a power tool in which a housing contains a motor, a circuit board, and a controller including a controller-side terminal electrically connected to the circuit board, and a switch including a switch-side terminal electrically connected to the controller-side terminal, The housing has an inner housing including a mounting plate interposed between the switch and the controller. The switch is held by a switch holding portion provided on one surface of the mounting plate, and the controller is held by a controller holding portion provided on the other surface. The controller-side terminal is provided on the surface of the controller on the mounting plate side, and the switch-side terminal is provided on the surface of the switch on the mounting plate side. wherein the controller-side terminal and the switch-side terminal through a through-hole provided in the mounting plate are in direct contact and electrically connected, On the surface of the controller on the mounting plate side, a resin cylindrical portion is provided to cover the periphery of the controller-side terminal and protrude to the switch side through the through-hole. On the surface of the switch on the mounting plate side, a second resin cylindrical portion is provided to cover the periphery of the switch-side terminal and protrude to the controller side through the through-hole. One of the cylindrical portion and the second cylindrical portion is inserted into the other. On the surface of the controller or the switch having the one cylindrical portion on the mounting plate side, the one cylindrical portion penetrates. and the peripheries of both terminals are sealed and is pressed by the other cylindrical portion in a state where the controller-side terminal and the switch-side terminal are in direct contact. a sheet-like elastic body is provided This is a feature of the present invention.

Advantages of the Invention

[0007] According to the present disclosure, the sealing performance between the controller and and the switch and can be ensured by a simple assembling operation. Therefore, high tightness can be imparted to the electrical connection part between the controller and the switch, effectively preventing a short circuit.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Mode for Carrying Out the Invention

[0009] In one embodiment of the present disclosure, the sealing body is provided on one of the first opposing surface and the second opposing surface, and on the other opposing surface, a resin cylindrical portion may be provided which abuts against the sealing body in a state where the controller-side terminal and the switch-side terminal are in direct contact to seal the periphery of both terminals. According to this configuration, the cylindrical portion is in surface contact with the sealing body, and high sealing performance can be obtained. In one embodiment of the present disclosure, on one of the opposing surfaces, a resin second cylindrical portion is provided which covers the periphery of the controller-side terminal or the switch-side terminal and protrudes toward the cylindrical portion side. In a state where the controller-side terminal and the switch-side terminal are in direct contact, one of the cylindrical portion and the second cylindrical portion may be inserted into the other cylindrical portion. According to this configuration, the labyrinth distance to the contact portion between the terminals can be lengthened, and the sealing performance can be enhanced. In one embodiment of the present disclosure, the cylindrical portion and the second cylindrical portion may be provided integrally with the controller or the switch. According to this configuration, the positions of the cylindrical portion and the second cylindrical portion are stable, and it becomes easier to insert one of the cylindrical portion and the second cylindrical portion into the other. In one embodiment of the present disclosure, the cylindrical portion and the second cylindrical portion may cover the entire periphery of the controller-side terminal or the switch-side terminal. According to this configuration, the controller-side terminal and the switch-side terminal are reliably protected.

[0010] In one embodiment of the present disclosure, the housing may have an inner housing interposed between the switch and the controller, a switch holding portion for holding the switch may be provided on one surface of the inner housing, and a controller holding portion for holding the controller may be provided on the other surface. And either one of the cylindrical portion and the second cylindrical portion may be inserted into the other cylindrical portion through a through hole provided in the inner housing. According to this configuration, the sealing performance of the electrical connection portion between the controller and the switch is enhanced, and the positioning of the cylindrical portion can also be performed by the through hole. In one embodiment of the present disclosure, switch positioning means for positioning the switch in the inner housing may be provided. According to this configuration, the switch can be stably positioned without rattling. In one embodiment of the present disclosure, controller positioning means for positioning the controller in the inner housing may be provided. According to this configuration, the controller can be stably positioned without rattling.

[0011] In one embodiment of the present disclosure, the switch has a housing and output terminals connected to the motor, and a terminal protection portion that non-contactly covers a part of the output terminals may be provided on the housing. According to this configuration, an effect of preventing short circuit between the output terminals can be obtained. In one embodiment of the present disclosure, the controller has a pair of power input terminals to which power is input to the circuit board, and protection portions for protecting the power input terminals may be provided on at least the opposing surfaces of the respective power input terminals. According to this configuration, an effect of preventing short circuit between the power input terminals can be obtained. In one embodiment of the present disclosure, the sealing body may be a sheet-like elastic body. According to this configuration, a wide sealing surface can be ensured, and the sealing performance is enhanced.

[0012] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. FIG. 1 is a side view of a grinder as an example of a power tool, FIG. 2 is a central longitudinal sectional view, and FIG. 3 is an enlarged view of the rear part of FIG. 2. The grinder 1 has, as a housing, a gear housing 2, a motor housing 3, and a rear cover 4 in order from the front. The gear housing 2 is made of metal, and the motor housing 3 and the rear cover 4 are made of resin. The gear housing 2 projects a spindle 5 downward. The motor housing 3 is cylindrical and extends in the front-rear direction, and houses a motor 6. A switch knob 7 is provided on the left side surface of the motor housing 3 so as to be slidable back and forth. The rear cover 4 has the same cylindrical shape as the motor housing 3, and houses a switch 8 and a controller 9. A power cord 10 is connected to the rear part of the rear cover 4. The motor 6 is a commutator motor having a stator 11, a rotor 12, and a commutator 13. An output shaft 14 provided on the rotor 12 extends forward and projects its tip into the gear housing 2. A bevel gear 15 is provided at the tip of the output shaft 14. A fan 16 is provided on the output shaft 14 at the front part of the motor housing 3.

[0013] A partition plate 17 through which the output shaft 14 passes is provided between the gear housing 2 and the motor housing 3. A bearing 18 for supporting the output shaft 14 is provided on the partition plate 17. A bevel gear 19 is provided above the spindle 5 in the gear housing 2. The bevel gear 19 meshes with the bevel gear 15 of the output shaft 14. A plurality of exhaust ports 20, 20... are formed on the front surface of the gear housing 2. A bearing box 21 is assembled to the lower part of the gear housing 2. The spindle 5 is supported by a bearing 22 held by the gear housing 2 and two bearings 23, 23 held by the bearing box 21. A tip tool 24 such as a disk-shaped grindstone can be attached to the lower end of the spindle 5 protruding from the bearing box 21.

[0014] At the rear end of the motor housing 3, an inner housing 25 is integrally formed. The inner housing 25 extends rearward within the rear cover 4. As also shown in FIGS. 4, 5, and 6, the inner housing 25 includes a front bearing holding portion 26, a pair of brush holding portions 27, 27 positioned above and below it, and a mounting plate 28. The bearing holding portion 26 is cylindrical with its axis in the front-rear direction, holds a bearing 29, and supports the rear end of the output shaft 14. The brush holding portions 27, 27 are each in a rectangular frame shape in plan view with upper and lower openings, and hold brushes 30, 30 that contact the commutator 13. The mounting plate 28 extends rearward from the bearing holding portion 26 and the brush holding portions 27, 27. The mounting plate 28 is formed parallel to the plane defined by the front-rear, left-right directions. The mounting plate 28 has, on the upper side, a switch holding portion 31 that holds the switch 8, and on the lower side, a controller holding portion 32 that holds the controller 9. On the upper surface of the mounting plate 28 behind the switch holding portion 31, a cord receiver portion 33 for clamping the power cord 10 is provided.

[0015] The switch holding portion 31 includes an upper holding wall 35, an upper assembly seat 36, and an upper screw boss 37. As also shown in FIG. 7, the upper holding wall 35 is a wall body that stands on the upper surface of the mounting plate 28 and has a rectangular shape in plan view with an open upper surface. The upper holding wall 35 has an upper front wall 38, left and right upper side walls 39A, 39B, and an upper rear wall 40. However, the left upper side wall 39A is formed only on the front side, and a notch 41 is formed on the rear side to open the left side of the upper holding wall 35. In the center of the upper front wall 38 in the left-right direction, a front rib 42 is provided in the up-down direction. The front rib 42 stands across the upper surface of the bearing holding portion 26 and the rear surface of the upper brush holding portion 27. Ventilation openings 43, 43 that penetrate front and rear are formed at the lower part of the connection portion between the upper front wall 38 and the left and right upper side walls 39A, 39B.

[0016] The front sides of the upper side walls 39A and 39B on the left and right are higher than the upper front wall 38 and the upper rear wall 40. A pair of concave grooves 44, 44 are formed in the vertical direction on the opposing inner surfaces of the upper side walls 39A, 39B. A locking claw 45 is formed in the front-rear direction on the outer surface of the left upper side wall 39A. A pair of partition ribs 46, 46 are formed in the vertical direction on the rear surface of the upper rear wall 40. A pair of holes 47, 47 are formed in the mounting plate 28 on the left and right outer sides of the partition ribs 46, 46. A through hole 48 having a horizontally long rectangular shape in plan view is formed in the mounting plate 28 between the upper side walls 39A and 39B on the left and right. The upper assembly seat 36 is formed in the left-right direction at a height one step lower than the upper surface of the rear part of the mounting plate 28 on the rear side of the through hole 48 between the upper side walls 39A and 39B on the left and right. A bottom rib 49 extending in the front-rear direction is provided at the center in the left-right direction of the upper assembly seat 36. The upper screw boss 37 is erected upward on the mounting plate 28 at a position on the rear side and to the right of the upper assembly seat 36.

[0017] As shown in FIG. 8, the controller holding portion 32 includes a lower holding wall 50 and a lower assembly seat 51. The lower holding wall 50 is a wall body that stands downward from the left and right side surfaces at the front part of the mounting plate 28 and surrounds the lower surface of the front part of the mounting plate 28. The lower holding wall 50 has a lower front wall 52 and left and right lower side walls 53A, 53B. The lower front wall 52 is integrally formed with the lower brush holding portion 27. The front parts of the left and right lower side walls 53A, 53B that are continuous with the lower front wall 52 are formed longer downward than the rear parts. On the outer surfaces of the front parts of the left and right lower side walls 53A, 53B, a pair of lower screw bosses 54, 54 are provided facing backward. The lower assembly seat 51 is formed on the entire lower surface of the mounting plate 28 including the area surrounded by the lower holding wall 50. A protrusion 55 is formed downward at the center in the left-right direction at the front part of the lower assembly seat 51. The protrusion 55 is located in front of the through hole 48. A recess 56 that is recessed upward is formed on the lower surface of the mounting plate 28 between the protrusion 55 and the holes 47, 47. The through hole 48 is located within the recess 56.

[0018] The switch 8 is a push switch that operates in the ON state by pressing a button 61 protruding from the housing 60. The housing 60 has a rectangular shape that fits between the upper left and right side walls 39A and 39B of the switch holding portion 31. The button 61 is provided on the rear surface of the housing 60 facing backward. On the upper front surface of the housing 60, as shown in FIG. 9, a pair of plate-shaped positive and negative output terminals 62, 62 are provided facing forward. On the upper plate of the housing 60, a pair of left and right protective plate portions 63, 63 that cover the output terminals 62, 62 except for the tip portions from above protrude forward. Between the left and right protective plate portions 63, 63, a pair of left and right ridges 64, 64 straddling the upper and front surfaces of the housing 60 are formed at a predetermined interval in the left and right directions. On the front surface of the housing 60 between the ridges 64, 64, a strip-shaped sealing material (here, sponge) 65 is adhered in the vertical direction. The sealing material 65 corresponds to a front rib 42 provided on the upper front wall 38 of the upper holding wall 35. On the left and right side surfaces of the housing 60, a pair of horizontal ribs 66, 66 are provided in the vertical direction. The horizontal ribs 66, 66 correspond to the concave grooves 44, 44 provided on the upper left and right side walls 39A, 39B of the upper holding wall 35.

[0019] In the front part of the housing 60, a pair of plate-shaped positive and negative switch-side terminals 67, 67 are provided facing downward. On the lower surface 8a of the switch 8, in the front part of the housing 60, a horizontally long square tube portion 68 that surrounds the front, rear, left, and right of the area including the switch-side terminals 67, 67 is formed facing downward. The lower surface of the square tube portion 68 is flat. Between the left and right switch-side terminals 67, 67 within the square tube portion 68, a partition plate portion 69 that partitions the square tube portion 68 in the left and right directions is provided facing downward. The lower end of the partition plate portion 69 is in the same plane as the lower end of the square tube portion 68. In the front plate of the housing 60, the lower part forming the front side of the square tube portion 68 is a separate closing plate 70. The closing plate 70 is integrated with the front plate by vibration welding or the like after the switch-side terminals 67, 67 are attached to the inside of the housing 60. By attaching the closing plate 70 in this way, the front surface of the housing 60 can be opened when assembling the switch-side terminals 67, 67, and it becomes easier to attach the switch-side terminals 67, 67. At the rear side of the angled cylinder portion 68, the lower surface of the rear part of the housing 60 is formed one step higher than the lower end of the angled cylinder portion 68, and a lower groove 71 is provided in the center in the left - right direction in the front - rear direction. The lower groove 71 corresponds to the bottom rib 49 provided on the upper - assembly seat 36.

[0020] Above the switch 8, a positioning plate 75 is provided. The positioning plate 75 has a rectangular shape in plan view with a length slightly larger than the left - right width of the housing 60. On the lower surface, fitting recesses 76 into which the ridges 64, 64 on the upper surface of the housing 60 are fitted are formed in the front - rear direction. In the fitting recess 76, fitting ribs 77 that fit between the ridges 64, 64 are formed in the front - rear direction. At the right - hand rear end of the rear end of the positioning plate 75, a rear - facing screwing piece 78 is provided. A through - hole 79 is formed in the screwing piece 78. The through - hole 79 corresponds to the upper screw boss 37 and can be screwed by a screw 80. On the left side of the screwing piece 78 and at the rear end of the positioning plate 75, a downward - facing rear - abutting piece 81 is formed. The lower end of the rear - abutting piece 81 can abut against the rear surface of the housing 60. On the left - hand edge of the positioning plate 75, a downward - facing lateral - abutting piece 82 is formed. The lateral - abutting piece 82 can abut against the outer surface of the upper side wall 39A on the left side of the upper holding wall 35. In the lateral - abutting piece 82, a locking hole 83 into which the locking claw 45 provided on the upper side wall 39A can be locked is formed.

[0021] As shown in FIG. 3, the controller 9 includes a case 85, a circuit board 86, a terminal board 87, and a heat sink 88. The case 85 has a left - right width that fits between the left and right lower side walls 53A, 53B of the controller - holding portion 32. As shown in FIGS. 7 and 8, the case 85 has a rectangular shape in plan view that extends in the front - rear direction. The case 85 has a dish - like shape with a peripheral wall 89 standing upright downward. Positioning pieces 90, 90 are formed on the left and right outer surfaces of the peripheral wall 89. Each positioning piece 90 has a through - hole 91 and corresponds to the lower screw bosses 54, 54 provided on the lower side walls 53A, 53B. In the center of the front part on the upper surface of the case 85, a recessed portion 92 is formed. The recessed portion 92 fits into the protrusion 55 provided on the mounting plate 28. The circuit board 86 has a left - right width that fits within the case 85. The circuit board 86 has a rectangular shape that extends in the front - rear direction in plan view. Control elements such as capacitors and triacs are mounted on the lower surface of the circuit board 86. A speed - change dial 93 of the motor 6 is provided on the lower surface of the rear end of the circuit board 86.

[0022] The terminal board 87 is made of resin and is assembled on the upper side of the circuit board 86. A pair of power - input terminals 94, 94 are mounted on the upper surface of the rear part of the terminal board 87. The power - input terminals 94, 94 are for connecting the power cord 10. The power - input terminals 94, 94 are integrally formed with the terminal board 87 and are held by protective cylinder parts 95, 95 that protrude upward and protrude upward. The protective cylinder parts 95, 95 can penetrate through holes 47, 47 provided in the rear part of the mounting plate 28. The power - input terminals 94, 94 are electrically connected to the circuit board 86. Screws 96, 96 for connecting the cable of the power cord 10 are screwed onto the upper ends of the power - input terminals 94, 94. In front of the power - input terminals 94, 94 on the terminal board 87, controller - side terminals 97, 97 are arranged. The controller - side terminals 97, 97 are for connecting the switch 8. The controller - side terminals 97, 97 are insert - molded into resin front cylinder parts 98, 98 and the upper ends are the connection sides of the switch 8. The upper end of each controller - side terminal 97 is a female terminal having a pair of front - rear terminal plates, and the switch - side terminal 67 of the switch 8 is inserted between the terminal plates of the controller - side terminal 97 and comes into contact with each other. The lower ends of the controller - side terminals 97, 97 are electrically connected to the circuit board 86. The front cylinder parts 98, 98 are sized to be inserted and fitted from below on the left and right of the square cylinder part 68 of the switch 8. The heat sink 88 is a metal plate that covers the circuit board 86 from below except for the speed - change dial 93. The heat sink 88 is connected by a triac and a screw and is in a thermally - contacting state.

[0023] The controller 9 houses a circuit board 86 with a terminal board 87 assembled on its upper surface and a heat sink 88 assembled on its lower surface in a case 85, and resin 99 is filled and molded above the heat sink 88 within the case 85. The power input terminals 94, 94 and the controller-side terminals 97, 97 project upward from the upper surface 9a of the controller 9. An elastic sheet 100 made of sponge is provided on the upper surface 9a of the controller 9. The elastic sheet 100 has a rectangular shape in plan view that covers the upper surface of the case 85 between the power input terminals 94, 94 and the recess 92. The front cylindrical portions 98, 98 of the controller-side terminals 97, 97 project upward through horizontally long relief holes 101 formed in the elastic sheet 100. These relief holes 101 are formed to be slightly smaller than the opening of the square cylindrical portion 68. Note that the elastic sheet 100 is formed to be long rearward including the periphery of the controller-side terminals 97, 97. This is to enable the elastic sheet 100 to be arranged in reverse front and back even when the switch 8 is mounted in the reverse front and back direction and the switch-side terminals 67, 67 are shifted to the rear side and the controller-side terminals 97 are also formed on the rear side. Also, the large area of the elastic sheet 100 enhances the sealing property with the mounting plate 28.

[0024] Next, the assembly of the switch 8 and the controller 9 will be described. The controller 9 is assembled with the heat sink 88 on the lower side and the speed change dial 93 on the rear side, and the recess 92 of the case 85 is fitted onto the protrusion 55 of the mounting plate 28 from below. Also, the power input terminals 94, 94 are passed through the holes 47, 47 of the mounting plate 28 from below, and the controller-side terminals 97, 97 are passed through the through holes 48 from below. In actual work, the mounting plate 28 is turned upside down, and the controller 9 is assembled to the mounting plate 28 from above. Then, with the left and right positioning pieces 90, 90 abutted against the rear sides of the lower screw bosses 54, 54, they are set on the lower assembly seat 51 of the mounting plate 28. At this position, screws 102, 102 passing through the through holes 91, 91 of the positioning pieces 90, 90 from the rear are screwed into the lower screw bosses 54, 54. Then, as shown in FIGS. 3, 6, and 11, the controller 9 is fixed to the lower assembly seat 51 of the mounting plate 28. The power input terminals 94, 94 protrude to the left and right outer sides of the partition ribs 46, 46 through the holes 47, 47 of the mounting plate 28 as shown in FIG. 10. The controller-side terminals 97, 97 protrude above the mounting plate 28 through the through holes 48 of the mounting plate 28.

[0025] The switch 8 is pushed in from above between the left and right upper side walls 39A, 39B with the button 61 at the rear side and the horizontal ribs 66, 66 of the housing 60 fitted into the left and right concave grooves 44, 44 of the upper holding wall 35. Then, the rear lower surface of the housing 60 is placed on the upper assembly seat 36, and the bottom rib 49 of the upper assembly seat 36 is fitted into the lower groove 71 on the lower surface of the housing 60. Also, the front rib 42 of the front upper wall 38 is fitted between the protruding strips 64, 64 on the front surface of the housing 60. Then, as shown in FIGS. 10 to 12, the square tube portion 68 of the housing 60 is fitted into the through hole 48 of the mounting plate 28, and the front tube portions 98, 98 of the controller-side terminals 97, 97 of the controller 9 protruding from the through hole 48 are inserted into the square tube portion 68 from below. Thus, the switch-side terminals 67, 67 are inserted and connected to the controller-side terminals 97, 97. However, the switch 8 and the controller 9 may be assembled in the reverse order. In this state, the positioning plate 75 is placed on the upper surface of the housing 60 with the protruding strips 64, 64 fitted into the fitting recess 76 and the fitting rib 77 fitted between the protruding strips 64, 64, and the locking claw 45 of the left upper side wall 39A is locked into the locking hole 83 of the horizontal abutting piece 82. Then, a screw 80 is inserted into the through hole 79 of the screwing piece 78 from above and screwed into the upper screw boss 37. Then, the housing 60 is pressed from above by the positioning plate 75 and fixed to the upper assembly seat 36.

[0026] At this time, the lower end of the square tube portion 68 presses and elastically deforms the elastic sheet 100 on the upper surface 9a of the controller 9. Therefore, the periphery of the connection portion between the switch-side terminals 67, 67 and the controller-side terminals 97, 97 is sealed by the close contact between the square tube portion 68 and the elastic sheet 100. At the same time, on the front surface of the housing 60, the front rib 42 presses and elastically deforms the sealing material 65. Therefore, between the front surface of the housing 60 and the upper front wall 38, it is sealed by the close contact between the front rib 42 and the sealing material 65 between the left and right output terminals 62, 62. Connectors 106, 106 (FIG. 12) of lead wires 105, 105 drawn from the stator 11 of the motor 6 are connected to the output terminals 62, 62. Each connector 106 is provided with an insulating cover 106a that covers the connection portion with the output terminal 62. Since the output terminals 62, 62 are partitioned by the front rib 42 and the sealing material 65 therebetween and are covered by the protective plate portions 63, 63 above, a short circuit due to iron powder or the like is less likely to occur. A pair of cables of the power cord 10 fixed to the cord receptacle 33 are electrically connected to the power input terminals 94, 94 by screws 96, 96. Since the power input terminals 94, 94 are also partitioned from each other by the partition ribs 46, 46 and the protective cylinder portions 95, 95 therebetween, a short circuit due to iron powder or the like is less likely to occur.

[0027] The switch knob 7 is connected to a slide bar 107 that extends in the front-rear direction on the left side of the upper holding wall 35 in the motor housing 3. The slide bar 107 has a pressing portion 108 that bends to the right. The pressing portion 108 protrudes into the upper holding wall 35 through the notch 41 of the upper holding wall 35 and is located behind the button 61 of the switch 8. When the slide bar 107 moves forward as the switch knob 7 slides forward, the pressing portion 108 presses the button 61. The slide bar 107 and the switch knob 7 are biased by a coil spring 109 provided between them to a retracted position where the pressing portion 108 does not press the button 61. The rear cover 4 is placed over the inner housing 25 with the switch 8 and the controller 9 assembled from the rear. At a position where the front end of the rear cover 4 overlaps the rear end of the motor housing 3, a screw 110 passed through from the rear surface is screwed into a boss portion 111 provided on the rear surface of the mounting plate 28. Then, the rear cover 4 is fixed to the inner housing 25. A plurality of air inlets 112, 112... are formed on the rear surface, left and right side surfaces, and lower surface of the rear cover 4.

[0028] In the grinder 1 configured as described above, slide the switch knob 7 forward. Then, the slide bar 107 moves forward and the pressing portion 108 presses the button 61 of the switch 8, so that the switch 8 operates to turn on. Therefore, the controller 9 drives the motor 6 to rotate the output shaft 14. Then, the spindle 5 rotates via the bevel gears 15, 19, enabling grinding operations and the like with the tip tool 24. When the fan 16 rotates as the output shaft 14 rotates, outside air is sucked in from each air inlet 112 of the rear cover 4. A part of the air sucked in from the air inlet 112 passes above the mounting plate 28 and between the upper holding wall 35 and the switch 8, and then becomes an air flow reaching the motor 6 from the ventilation holes 43, 43. Therefore, the switch 8 and the motor 6 are cooled. The air sucked in from the air inlet 112 on the lower surface becomes an air flow reaching the motor 6 after passing through the heat sink 88. Therefore, the air flow intensively contacts the heat sink 88, promoting the heat dissipation of the controller 9 (especially the triac). When the forward slide of the switch knob 7 is released, the slide bar 107 retreats by the biasing force of the coil spring, releasing the pressing of the button 61 by the pressing portion 108. Therefore, the switch 8 turns off and the driving of the motor 6 stops.

[0029] Thus, the grinder 1 of the above-described embodiment includes, within the rear cover 4 (housing), a motor 6, a controller 9 including a circuit board 86 and a controller-side terminal 97 electrically connected to the circuit board 86, and a switch 8 including a switch-side terminal 67 electrically connected to the controller-side terminal 97. The controller-side terminal 97 is disposed on the upper surface 9a (the first opposing surface on the switch side) of the controller 9, and the switch-side terminal 67 is disposed on the lower surface 8a (the second opposing surface on the controller side) of the switch 8, such that the controller-side terminal 97 and the switch-side terminal 67 are in direct contact and electrically connected. An elastic sheet 100 (sealing body) that seals the periphery of both terminals 97, 67 in a state where the controller-side terminal 97 and the switch-side terminal 67 are in direct contact is interposed between the upper surface 9a of the controller 9 and the lower surface 8a of the switch 8. According to this configuration, the sealing property between the upper surface 9a of the controller 9 and the lower surface 8a of the switch 8 can be ensured by the elastic sheet 100 with a simple assembling operation. Therefore, high tightness can be imparted to the electrical connection portion between the controller 9 and the switch 8, effectively preventing a short circuit.

[0030] In particular, the elastic sheet 100 is provided on the upper surface 9a of the controller 9, and a resin square tube portion 68 (tube portion) that abuts against the elastic sheet 100 in a state where the controller-side terminal 97 and the switch-side terminal 67 are in direct contact and seals the periphery of both terminals 97, 67 is provided on the lower surface 8a of the switch 8. Therefore, a high sealing property is obtained due to the surface contact between the elastic sheet 100 and the square tube portion 68. A resin front tube portion 98 (second tube portion) that covers the periphery of the controller-side terminal 97 and protrudes toward the square tube portion 68 is provided on the upper surface 9a of the controller 9. In a state where the controller-side terminal 97 and the switch-side terminal 67 are in direct contact, the front tube portion 98 is inserted into the square tube portion 68. Therefore, the labyrinth distance to the contact portion between the terminals can be increased, enhancing the sealing property. The corner tube portion 68 and the front tube portion 98 are provided integrally with the controller 9 or the switch 8. Therefore, the positions of the front tube portion 98 and the corner tube portion 68 are stabilized, and it becomes easier to insert the front tube portion 98 into the corner tube portion 68. The corner tube portion 68 and the front tube portion 98 cover the entire periphery of the controller-side terminal 97 or the switch-side terminal 67. Therefore, the controller-side terminal 97 and the switch-side terminal 67 are reliably protected.

[0031] The motor housing 3 (housing) has an inner housing 25 interposed between the switch 8 and the controller 9. On the upper surface of the inner housing 25, a switch holding portion 31 for holding the switch 8 is provided, and on the lower surface, a controller holding portion 32 for holding the controller 9 is provided. And the corner tube portion 68 is inserted into the front tube portion 98 through a through hole 48 provided in the inner housing 25. Therefore, the sealing property of the electrical connection portion between the controller 9 and the switch 8 is enhanced, and the positioning of the corner tube portion 68 can also be performed by the through hole 48. An upper screw boss 37, a positioning plate 75, and a screw 80 (switch positioning means) for positioning the switch 8 on the inner housing 25 are provided. Therefore, the switch 8 can be stably positioned without rattling. A lower screw boss 54, a positioning piece 90, and a screw 102 (controller positioning means) for positioning the controller 9 on the inner housing 25 are provided. Therefore, the controller 9 can be stably positioned without rattling.

[0032] The switch 8 has a housing 60 and an output terminal 62 connected to the motor 6. On the housing 60, a protection plate portion 63 (terminal protection portion) that non-contactingly covers a part of the output terminal 62 is provided. Therefore, the effect of preventing a short circuit between the output terminals 62, 62 is obtained. The controller 9 has a pair of power input terminals 94, 94 to which power is input to the circuit board 86, and protective cylinder portions 95 (protective portions) for protecting the power input terminals 94 are provided on at least the opposing surfaces of each other at each power input terminal 94. Therefore, an effect of preventing a short circuit between the power input terminals 94, 94 can be obtained. The sealing body is an elastic sheet 100 (sheet-like elastic body). Therefore, a wide sealing surface can be secured and the sealing property is enhanced.

[0033] Hereinafter, modified examples will be described. In the above-described embodiment, an elastic sheet is used as the sealing body provided in the case of the controller. However, a strip-shaped sealing body may be arranged in an L-shaped ring so as to surround the periphery of the controller-side terminal. The sealing body is not limited to sponge, and rubber or the like may be used. In the above-described embodiment, the peripheries of the two switch-side terminals are covered with one L-shaped cylinder portion. However, an L-shaped cylinder portion may be provided for each switch-side terminal. In this case, each L-shaped cylinder portion may be inserted into each front cylinder portion of the controller-side terminal. In the above-described embodiment, an L-shaped cylinder portion is provided in the housing of the switch, and a sealing body (elastic sheet) is provided in the case of the controller. Conversely, an L-shaped cylinder portion may be provided in the case of the controller, and a sealing body may be provided in the housing of the switch. The shape of the terminal is not limited to the above-described embodiment. The switch-side terminal may be the female side and the controller-side terminal may be the male side. The L-shaped cylinder portion and the second L-shaped cylinder portion are not limited to the L-shaped cylinder as in the above-described embodiment, and may be a circular cylinder. It is not limited to covering the entire periphery of the terminal, and may be shorter than the terminal. The cylindrical portion and the second cylindrical portion can be omitted. For example, the controller may not include a case, and may be in a form in which the circuit board is coated with an insulating material or a plate material is partially attached. In this case, the controller-side terminals are arranged on the surface (the first opposing surface) formed on the switch side in the controller. Similarly, the switch may not include a housing. In this case, the switch-side terminals are arranged on the surface (the second opposing surface) formed on the controller side in the switch. Therefore, a sealing body that covers the periphery of both terminals may be interposed between the two opposing surfaces.

[0034] In the above form, the switch is arranged on the upper side and the controller is arranged on the lower side. Conversely, the switch may be on the lower side and the controller may be on the upper side, or the switch and the controller may be arranged left and right. The switch may be arranged with the button facing forward. The ON / OFF operation of the switch may be performed by the pressing portion of the slide bar regardless of the direction of the button, or may be performed by a link member that swings in conjunction with the sliding of the slide bar. The switch may be one that performs an ON / OFF operation by swinging a lever instead of pressing a button. The shape of the housing is not limited to the above form. For example, an integral square tube portion may be formed in the housing by eliminating the closing plate. The positioning means of the switch is not limited to the positioning plate in the above form. The position and number of the screws may be changed, or the housing may be directly screwed to the inner housing without using the positioning plate. The positioning is not limited to the means using screws, and may be performed by locking a locking piece provided on the inner housing to the housing. The terminal protection portion of the output terminal is not limited to the protection plate portion that covers only the upper surface as in the above form. It may be semi-cylindrical or cylindrical to cover a plurality of surfaces of the output terminal. The terminal protection portion can also be omitted. The seal between the output terminals may be provided with ribs on the housing side and a sealing material on the inner housing side, contrary to the above form. The shapes of the ribs and the sealing material can be changed as appropriate. Sealing may be performed by the contact of the ribs without providing a sealing material. The seal between the output terminals can also be omitted.

[0035] The positioning means of the controller is not limited to the lower screw boss and the positioning piece of the above form. A screw boss may be provided on the case and a positioning piece may be provided on the controller holding portion. Similar to the case of the switch, it is not limited to positioning using screws, and the locking piece provided on the inner housing may be locked to the case. The protection part of the power input terminal is not limited to the protection cylinder part of the above form. It may be a wall body that covers only the opposing surface of the power input terminal, or the protection part may be omitted. The power cord may be electrically connected by means other than screws. The shapes of the case and the circuit board are not limited to the above form. It is not limited to a shape extending in the front-rear direction, and may be a shape extending in the left-right direction. Other shapes such as a square in plan view can also be adopted. The speed change dial can also be omitted in addition to changing its shape and position. The shape and position of the heat sink are not limited to the above form. It may not have a heat sink.

[0036] In addition, the structure of the grinder is not limited to the above form. A brushless motor may be adopted as the motor. A brake mechanism for the output shaft may be provided at the front part of the motor housing. The power tool is not limited to a grinder. The present disclosure is also applicable to other power tools such as a polisher, an angle screw driver, and an angle impact driver. The power tool may be a DC machine using a battery as a power source.

Explanation of Reference Numerals

[0037] 1. Grinder, 2. Gear housing, 3. Motor housing, 4. Rear cover, 5. Spindle, 6. Motor, 8. Switch, 8a. Lower surface, 9. Controller, 9a. Upper surface, 14. Output shaft, 25. Inner housing, 26. Bearing holding part, 27. Brush holding part, 28. Mounting plate, 31. Switch holding part, 32. Controller holding part, 35. Upper holding wall, 36. Upper assembly seat, 37. Upper screw boss, 38. Front upper wall, 39A, 39B. Upper side walls, 42. Front rib, 48. Through hole, 50. Lower holding wall, 51. Lower assembly seat, 52. Front lower wall, 53A, 53B. Lower side walls, 54. Lower screw boss, 60. Housing, 61. Button, 62. Output terminal, 63. Protective plate part, 65. Sealing material, 67. Switch side terminal, 68. Square tube part, 75. Positioning plate, 85. Case, 86. Circuit board, 87. Terminal board, 88. Heat sink, 90. Positioning piece, 94. Power input terminal, 95. Protective cylinder part, 97. Controller side terminal, 98. Front cylinder part, 100. Elastic sheet.

Claims

1. Inside a housing, a motor, a circuit board, and a controller including a controller-side terminal electrically connected to the circuit board, a switch including a switch-side terminal electrically connected to the controller-side terminal are accommodated, the housing has an inner housing including a mounting plate interposed between the switch and the controller, the switch is held by a switch holding portion provided on one surface of the mounting plate, and the controller is held by a controller holding portion provided on the other surface, the controller-side terminal is provided on the surface of the controller on the mounting plate side, the switch-side terminal is provided on the surface of the switch on the mounting plate side, and the controller-side terminal and the switch-side terminal are in direct contact with each other through a through hole provided in the mounting plate and electrically connected, and the electric power tool is a resin cylindrical portion that covers the periphery of the controller-side terminal and protrudes to the switch side through the through hole is provided on the surface of the controller on the mounting plate side, and a resin second cylindrical portion that covers the periphery of the switch-side terminal and protrudes to the controller side through the through hole is provided on the surface of the switch on the mounting plate side, and one of the cylindrical portion and the second cylindrical portion is inserted into the other cylindrical portion, a sheet-like elastic body that penetrates the one cylindrical portion and presses the other cylindrical portion in a state where the controller-side terminal and the switch-side terminal are in direct contact with each other to seal the periphery of both terminals is provided on the surface of the mounting plate side of the controller or the switch having the one cylindrical portion. The electric power tool is characterized by this.

2. The electric power tool according to claim 1, wherein the cylindrical portion and the second cylindrical portion are provided integrally with the controller or the switch.

3. The electric power tool according to claim 1 or 2, wherein the cylindrical portion and the second cylindrical portion cover the entire periphery of the controller-side terminal or the switch-side terminal.

4. The electric power tool according to any one of claims 1 to 3, wherein switch positioning means for positioning the switch in the inner housing is provided.

5. The electric power tool according to any one of claims 1 to 4, wherein controller positioning means for positioning the controller in the inner housing is provided.

6. The switch has a housing and positive and negative output terminals connected to the motor, and a terminal protection part that non - contactingly covers a part of the output terminals is provided on the housing, and the power tool according to any one of claims 1 to 5, characterized in that.

7. A pair of ridges are provided between the positive and negative output terminals in the housing, and a sealing material is disposed between the ridges, while a rib that protrudes between the ridges and presses the sealing material is provided on the switch holding part in a state where the switch is held, and the power tool according to claim 6, characterized in that.

8. The controller has a pair of power input terminals to which power is input to the circuit board, and protection parts for protecting the power input terminals are respectively provided on at least the opposing surfaces of each of the power input terminals, and the power tool according to any one of claims 1 to 7, characterized in that.

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