CN112139981A - Grinding machine - Google Patents

Abstract

The invention provides a grinder. The grinding mill (1) comprises: an inner case (3) that houses the brushless motor (4); a spindle (6) disposed in front of the brushless motor (4); and an outer housing (2) in which an inner housing (3) is disposed on the inside and the outer housing (2) and a rear cylinder (8) are provided integrally, wherein the inner housing (3) and the outer housing (2) are connected to each other in a relatively rotatable manner by a connecting rod (75) that is parallel to the main shaft (6), and the inner housing (3) is held by the outer housing (2) by a cylindrical rubber (80) disposed in front of the connecting rod (75). Accordingly, it is possible to effectively reduce the transmission of vibration or reaction force to the worker, and improve the feeling of use and operability.

Description

Grinding machine

Technical Field

The present invention relates to a grinder (grind) having a final output shaft provided at a front portion of a housing extending in a front-rear direction and capable of mounting a tool at a tip end thereof to a lower end thereof.

Background

As disclosed in patent document 1, a grinding machine is also configured such that a spindle, which is a final output shaft, is provided downward at a front portion of a housing extending in the front-rear direction, and a tip tool such as a disk-shaped grinding wheel is attached to a lower end of the spindle, so that grinding work or the like can be performed by rotation of the tip tool.

[ Prior art documents ]

[ patent document ]

Patent document 1: japanese patent laid-open publication No. 2013-119129

Disclosure of Invention

[ technical problem to be solved by the invention ]

In such a grinding machine, vibration may occur due to imbalance of a motor rotating at a high speed and imbalance of a tip tool attached to a spindle. This vibration is transmitted to the hand of the worker through the housing in which the motor is housed or the side handle attached to the housing, and therefore, there is a concern that the worker may feel uncomfortable or the operability may be affected.

Further, when the motor is started or a load is applied to the tool bit, the housing is shaken in a direction opposite to the rotation direction of the tool bit by a reaction force, which also causes deterioration of operability.

Accordingly, an object of the present invention is to provide a grinder capable of effectively reducing vibration or reaction force transmitted to a worker, thereby improving a feeling of use or operability.

[ technical means for solving problems ]

In order to achieve the above object, the invention according to claim 1 is characterized by comprising an inner housing, a final output shaft, and an outer housing, wherein the inner housing houses a motor; the final output shaft is arranged in front of the motor; an inner case is disposed inside the outer case, and a handle is integrally provided on the outer case, the inner case and the outer case are connected to each other by a connecting shaft parallel to the final output shaft so as to be relatively rotatable, and the inner case is held by the outer case by a front-side elastic body disposed in front of the connecting shaft.

The invention according to claim 2 is characterized in that, in addition to the structure according to claim 1, the inner case and the coupling shaft are coupled to each other by a rear-side elastic body.

The invention according to claim 3 is characterized in that, in addition to the structure according to claim 1 or 2, the coupling shaft is directly held by the outer housing.

The invention according to claim 4 is characterized in that, in addition to the configuration according to any one of claim 1 to claim 3, a 1 st engaging portion is provided on one of the inner case and the front side elastic body, a 1 st engaged portion is provided on the other of the inner case and the front side elastic body, the 1 st engaged portion is engaged with the 1 st engaging portion in a rotational direction about an axis in the front-rear direction, a 2 nd engaging portion is provided on one of the front side elastic body and the outer case, a 2 nd engaged portion is provided on the other of the front side elastic body and the outer case, and the 2 nd engaged portion is engaged with the 2 nd engaging portion in the rotational direction.

The invention according to claim 5 is characterized in that, in addition to the configuration according to claim 4, a protrusion serving as a 1 st engaging portion is provided on an outer surface of the inner case, a 1 st engaged portion with which the protrusion is engaged is provided on the front side elastic body, a portion including the 1 st engaged portion is formed on a 2 nd engaging portion protruding toward an outer surface side of the front side elastic body, and a recess serving as a 2 nd engaged portion is formed on an inner surface of the outer case.

The invention according to claim 6 is characterized in that, in addition to the configuration according to claim 1, the coupling shaft is held in the outer case by a rear-side elastic body.

The invention according to claim 7 is characterized in that, in addition to the configuration according to any one of claims 1 to 6 or the configuration according to claim 2, an attachment portion of the side handle is provided on the outer case.

The invention according to claim 8 is characterized in that, in addition to the structure according to any one of claims 1 to 7, the outer case is formed by assembling a pair of right and left split cases, and each split case is fixed to a ring attached to the outside of the inner case by a front-side elastic body.

The invention according to claim 9 is characterized in that, in addition to the structure according to any one of claims 1 to 8, a coupling portion of the inner case to be coupled to the coupling shaft is made of metal.

The invention according to claim 10 is characterized in that, in addition to the configuration according to any one of claims 1 to 9, a housing portion of the motor in the inner case is cylindrical.

The invention according to claim 11 is characterized in that, in addition to the configuration according to any one of claims 1 to 10, electronic components other than the motor are housed in the outer case.

The invention according to claim 12 is characterized in that, in addition to the configuration according to any one of claims 1 to 11, a battery serving as a power source is provided in the outer case.

The invention according to claim 13 is characterized in that, in addition to the structure according to any one of claims 1 to 12, the rear-side elastic body has a lower hardness than the front-side elastic body.

[ Effect of the invention ]

According to the invention described in claim 1, since the inner case and the outer case are coupled to each other so as to be relatively rotatable by the coupling shaft parallel to the final output shaft, and the inner case is held by the outer case by the front-side elastic body disposed in front of the coupling shaft, it is possible to effectively reduce the transmission of vibration or reaction force to the author, and to improve the feeling of use and the operability.

According to the invention described in claim 2, in addition to the above-described effects, since the inner housing and the coupling shaft are coupled by the rear-side elastic body, the coupling shaft can be supported at an appropriate position by the outer housing without being tilted. Therefore, the inner housing does not tilt or the like, and the output shaft can be supported at an appropriate position.

According to the invention of claim 3, in addition to the above-described effects, since the coupling shaft is directly held by the outer housing, the coupling shaft can be assembled to the outer housing and the coupling shaft can be pivoted to an appropriate position.

According to the invention of claim 4, in addition to the above-described effects, since the 1 st engaging portion is provided on one of the inner case and the front side elastic body, the 1 st engaged portion is provided on the other of the inner case and the front side elastic body, the 2 nd engaging portion is provided on one of the front side elastic body and the outer case, and the 2 nd engaged portion is provided on the other of the front side elastic body and the outer case, relative rattling between the outer case and the inner case is restricted in the rotational direction of the front side elastic body, and positioning with high reliability can be performed.

According to the invention of claim 5, in addition to the above-described effects, since the projection serving as the 1 st engaging portion is provided on the outer surface of the inner case, the 1 st engaged portion with which the projection is engaged is provided on the front side elastic body, the portion including the 1 st engaged portion is formed on the 2 nd engaging portion protruding toward the outer surface side of the front side elastic body, and the recess serving as the 2 nd engaged portion is formed on the inner surface of the outer case. Therefore, the outer housing and the inner housing can be positioned in the rotational direction by the front side elastic body efficiently.

According to the invention described in claim 6, in addition to the above-described effects, since the coupling shaft is held in the outer housing by the rear-side elastic body, it is possible to effectively reduce vibration transmitted from the coupling shaft to the outer housing.

According to the invention of claim 7, in addition to the above-described effects, since the mounting portion of the side grip is provided in the outer case, it is possible to effectively prevent the vibration and the reaction force from being transmitted to the side grip.

According to the invention of claim 8, in addition to the above-described effects, since the split case of the outer case is fixed to the ring attached to the outside of the inner case by the front-side elastic body, the split cases can be firmly coupled to each other by the ring.

According to the invention of claim 9, in addition to the above-described effects, since the portion of the inner housing that is coupled to the coupling shaft is made of metal, the strength of the coupling portion can be ensured.

According to the invention of claim 10, in addition to the above-described effects, since the housing portion of the motor in the inner case is formed in a tubular shape, vibration can be effectively isolated by the front side elastic body over the entire circumference.

According to the invention of claim 11, in addition to the above-described effects, since the electronic components other than the motor are housed in the outer case, the electronic components can be disposed in a state of being isolated from the vibration at a position away from the motor or the tip tool as the vibration source, and thus the electronic components can be protected from the vibration.

According to the invention according to claim 12, in addition to the above effects, since the battery serving as a power source is provided in the outer case, the mass of the outer case is increased, thereby effectively reducing vibration.

According to the invention of claim 13, in addition to the above-described effects, since the hardness of the rear side elastic body is lower than that of the front side elastic body, transmission of the reaction force can be effectively prevented.

Drawings

Fig. 1 is a perspective view of a grinder.

Fig. 2 is a top view of the grinding mill.

Fig. 3 is a left side view of the grinder.

Fig. 4 is a central longitudinal section of the mill.

Fig. 5 is a partially enlarged sectional view a-a of fig. 4.

Fig. 6 (a) is an enlarged sectional view of B-B of fig. 4, and fig. 6 (B) is an enlarged sectional view of C-C.

Fig. 7 (a) is an enlarged sectional view of D-D of fig. 4, and fig. 7 (B) is an enlarged sectional view of E-E.

Fig. 8 (a) is an enlarged sectional view of F-F of fig. 4, and fig. 8 (B) is an enlarged sectional view of G-G of fig. 5.

Fig. 9 is an exploded perspective view showing a holding structure of the inner housing and the brushless motor.

Fig. 10 is an exploded perspective view of the handle detection mechanism.

Fig. 11 is a partially enlarged vertical cross-sectional view of a grinder showing a modification of the elastic holding structure of the inner housing.

Fig. 12 is a sectional view H-H of fig. 11.

Fig. 13 is an exploded perspective view showing a modification of the elastic holding structure of the inner case.

Fig. 14 is a sectional view taken along line I-I of fig. 11.

Fig. 15 (a) is a sectional view of J-J of fig. 11, and fig. 15 (B) is a sectional view of K-K.

[ description of reference ]

1. 1A: a charging type grinder; 2: an outer housing; 3: an inner housing; 4: a brushless motor; 5: a gear housing; 6: a main shaft; 7: a front barrel portion; 8: a rear cylinder part; 9: a battery mounting portion; 10: a large diameter portion; 11: a battery pack (battery pack); 20: a controller; 25: a side handle; 26: a threaded portion; 30: a pyramid part; 31: an expansion section; 32: a stator; 33: a rotor; 50: bearing retainers (bearing retainer); 51: a bearing holding portion; 53: a connecting portion; 61: a locking ring; 65: a rotating shaft; 75. 75A: a connecting rod; 76. 76A: a lever receiving section; 78: rubber end caps (rubber caps); 80: a cylindrical rubber; 81: a fixing ring; 83: a handle mounting portion; 86: a handle detection mechanism; 87: detecting a plate; 88: a Photo-interrupter (Photo-interrupter); 93: a visor; 97: a light receiving section; 98: a receiving part; 107: a tip tool; 115: an inner case side protrusion; 125: a small diameter part; 126: a large diameter part; 128: a rubber sleeve; 133: a bulging portion; 134: a central slit; 135: an outer slit; 140: a recess; 141: the outer case side is protruded.

Detailed Description

Embodiments of the present invention will be described below with reference to the drawings.

Fig. 1 is a perspective view of a rechargeable grinder, which is also an example of a power tool, fig. 2 is a plan view thereof, fig. 3 is a left side view thereof, and fig. 4 is a central longitudinal sectional view thereof.

The grinding mill 1 has, as a housing, a cylindrical outer housing 2, the cylindrical outer housing 2 extending in the front-rear direction, a cylindrical inner housing 3, and a gear housing 5; the cylindrical inner housing 3 holds the brushless motor 4 in the outer housing 2 and projects forward; the gear housing 5 is coupled to a front side of the inner housing 3 and protrudes the main shaft 6 downward.

The outer case 2 is a resin-made member formed by integrally forming a large-diameter front cylindrical portion 7, which holds the inner case 3, a small-diameter rear cylindrical portion 8, and a battery mounting portion 9, and is formed by assembling a pair of left and right split cases 2a, 2b with screws; the small-diameter rear cylinder portion 8 is formed at a position eccentric upward behind the outer case 2; the battery mounting portion 9 is formed at the rear end of the rear tube portion 8. The front end of the front tubular portion 7 is a large diameter portion 10 that expands further forward. A battery pack 11 serving as a power source is slidably attached to the battery mounting portion 9 from above.

A main switch 12 is disposed in the rear cylindrical portion 8 of the outer case 2, and the main switch 12 projects a plunger 13 downward at a mechanical contact point where conduction is made from a terminal 24 to be described later to the control circuit board 21 by an ON Operation (ON). A micro switch (microswitch)14 is disposed ON the rear cylinder 8 ON the front side of the main switch 12, and the micro switch 14 projects the push button 15 downward at an electrical contact point where the control circuit board 21 is electrically connected to the brushless motor 4 by an ON Operation (ON). A switch lever 16 is provided on the lower side of the outer case 2 so as to be swingable in the vertical direction, extends rearward while being bent from the front tube portion 7 with the front end as a fulcrum in conformity with the shape of the lower surface of the rear tube portion 8, and the switch lever 16 is biased to a downward projecting position in a normal state by a coil spring 17 provided between the rear portion of the switch lever 16 and the lower surface of the rear tube portion 8.

A pressing plate 18 that presses the plunger 13 of the main switch 12 by an upward pressing operation is provided in the switch operation lever 16, and an unlocking operation lever 19 that is urged to rotate to the vertical posture in fig. 4 in a normal state is provided in front of the pressing plate 18, and the pressing of the switch operation lever 16 is restricted by the unlocking operation lever 19 being urged to rotate to the left in the same drawing, and the pressing of the switch operation lever 16 is permitted. Here, the rear tube portion 8 is used as a main lever, and when the unlocking lever 19 is rotated leftward by a finger gripping the rear tube portion 8 and then the switch lever 16 is gripped, the plunger 13 of the main switch 12 is pressed by the pressing plate 18 of the switch lever 16, and then the push button portion 15 of the microswitch 14 is pressed by the unlocking lever 19.

The controller 20 is supported in an inclined posture in which a lower end is positioned forward of an upper end with respect to an axis of the rear cylindrical portion 8 of the outer case 2 behind the main switch 12, wherein the controller 20 is formed by housing a control circuit board 21 in an aluminum and disk-shaped case 22, and the control circuit board 21 is mounted with 6 FETs (not shown), capacitors (capacitors), a microcomputer (not shown), and the like corresponding to the respective coils 37 of the brushless motor 4. Slit-shaped air inlets 23, 23 … are formed on the right and left sides of the battery mounting portion 9 behind the controller 20. The terminal 24 electrically connected by slidably mounting the battery pack 11 from above is held in a vertical posture behind the air inlet 23.

In this way, the electronic components other than the brushless motor 4 are housed in the outer case 2 at the rear of the inner case 3.

On the other hand, the inner housing 3 is a resin housing having a smaller diameter than the front cylindrical portion 7 of the outer housing 2 and housed in the front cylindrical portion 7, and as shown in fig. 5, a tapered portion 30 and an expanded portion 31 are formed at a front end protruding forward from the outer housing 2, the tapered portion 30 having a larger diameter as it goes forward; the expanding portion 31 extends forward from the front end of the tapered portion 30 and has substantially the same outer diameter as the large diameter portion 10 of the front cylinder portion 7.

The brushless motor 4 is an inner rotor type including a cylindrical stator 32 and a rotor 33 penetrating the inside thereof, and the stator 32 includes: a cylindrical stator core 34 formed of a plurality of laminated steel plates; a front insulator (insulator)35 and a rear insulator 36 provided on the front and rear end surfaces of the stator core 34 in the axial direction; and coils 37, 37 … wound around stator core 34 via front insulator 35 and rear insulator 36. A sensor circuit board 38 and a wiring member 40 are assembled on the rear insulator 36, wherein the sensor circuit board 38 detects the position of the permanent magnet 67 inserted into the rotor core; the wire connecting member 40 has a terminal fitting 41 for connecting (connecting) the coils 37 via Fusion terminals 39.

As shown in fig. 6 and 9, 4 convex portions 42 and 42 … … protruding toward the axial center side are formed on the front inner surface of the inner case 3 in the front-rear direction at equal intervals in the circumferential direction. The front portion of the convex portion 42 has a 1 st protruding portion 43 and a 2 nd protruding portion 44 whose protruding amount (thickness) from the inner surface becomes larger in stages toward the front of the inner case 3.

A pair of upper and lower fitting recesses 45, 45 and a pair of left and right chamfered portions 46, 46 are formed in the front insulator 35, wherein the upper and lower fitting recesses 45, 45 are fitted to the 2 nd projecting portion 44 in phase with the upper and lower projecting portions 42, 42; the pair of left and right chamfered portions 46, 46 coincide with the phases of the left and right protrusions 42, 42 without interfering with the 2 nd protrusion 44.

Accordingly, when the fitting recesses 45, 45 are aligned with the phases of the upper and lower protrusions 42, the chamfered portions 46, 46 are aligned with the phases of the left and right protrusions 42, and the stator 32 is inserted from the rear of the inner housing 3, the 2 nd protrusions 44, 44 of the upper and lower protrusions 42, 42 are fitted into the fitting recesses 45, the stator 32 is stopped from rotating, and the stator core 34 abuts against the 1 st protrusion 43 of each protrusion 42, whereby the forward position is defined. As shown in fig. 6 (B), in this state, the inner surfaces of the projections 42, except for the 1 st projection 43 and the 2 nd projection 44, are in contact with the outer surface of the stator core 34, and the stator core 34 is held.

An annular baffle plate (pocket plate)47 is fitted into the inner housing 3 on the front side of each projection 42 from the front. As shown in fig. 5 and 6, the retainer 47 is positioned by locking the hook pieces 48 and 48 provided on the left and right sides to the 2 nd projecting portions 44 and 44 of the left and right projecting portions 42 and 42 on the outer sides of the chamfered portions 46 and 46 of the front insulator 35, respectively.

A bearing holder (bearing roller) 50 made of metal is fitted to the rear end of the inner housing 3 from the rear. The bearing holder 50 is disk-shaped, and has a bearing holding portion 51 opened forward at the center, and as shown in fig. 7 (a) and 9, a plurality of circular arc-shaped through holes 52, 52 … … are formed around the bearing holding portion 51, and a coupling portion 53 is provided at the rear portion of the bearing holding portion 51, and the coupling portion 53 protrudes rearward and has a through hole 54 in the vertical direction.

Further, 4 pins 55, 55 … having a large diameter at the base 56 are projected on the front surface of the bearing holder 50 at equal intervals concentrically.

On the other hand, a thick portion 58 having an inner diameter into which the bearing holder 50 can be fitted is provided projecting from the rear inner surface of the inner housing 3. As shown in fig. 7 (B), 4V-shaped notches 59 and 59 … are formed at equal intervals in the circumferential direction on the outer periphery of the rear insulator 36.

Accordingly, when the bearing holder 50 is inserted into the thick portion 58 from the rear of the inner housing 3 with the pins 55 aligned in phase with the notches 59 of the rear insulator 36, as shown in fig. 7 (B), the pins 55 engage with the notches 59 and abut against the rear surface of the stator core 34, and the base portions 56 approach the rear surface of the rear insulator 36.

A female screw portion 60 is formed on the inner periphery of the rear end of the bearing holder 50, and in a state where the bearing holder 50 is inserted into the thick portion 58, the locking ring 61 made of resin is screwed into the female screw portion 60, whereby the bearing holder 50 is pressed from behind by the locking ring 61 and is prevented from falling off. In this state, the coupling portion 53 penetrates the center of the lock ring 61 and protrudes rearward of the inner housing 3.

The rotor 33 has: a rotating shaft 65 located at the axial center; a substantially cylindrical rotor core 66 disposed around the rotating shaft 65 and formed by stacking a plurality of steel plates; and 4 plate-like permanent magnets 67 and 67 … fixed inside the rotor core 66.

The rear end of the rotary shaft 65 is pivotally supported by a bearing 68 held by the bearing holding portion 51 of the bearing holder 50, and the front end of the rotary shaft 65 is pivotally supported by a bearing 70 held by a partition plate 69, the partition plate 69 being assembled between the gear housing 5 and the expanding portion 31 of the inner housing 3, and the front end thereof projecting into the gear housing 5. A centrifugal fan 71 is assembled to the rotary shaft 65 behind the partition plate 69, and the centrifugal fan 71 is housed in front of the baffle plate 47 across the expanding portion 31 from the tapered portion 30 of the inner housing 3.

(Explanation of elastic holding structure of inner case)

The inner housing 3 holding the brushless motor 4 in this manner is elastically held by the outer housing 2. The elastic holding structure will be described in detail below.

First, in the bearing holder 50, a metal coupling rod 75 is inserted in the through hole 54 of the coupling portion 53 projecting rearward from the inner housing 3 in the vertical direction. As shown in fig. 8 (a) and 9, the connecting rod 75 is a member in which upper and lower ends are supported by a pair of upper and lower square cylindrical rod receiving portions 76, the pair of upper and lower square cylindrical rod receiving portions 76, 76 being formed by fitting with the half portions of the half- shell bodies 2a, 2b formed in the outer shell 2, respectively, the rod receiving portions 76 forming insertion holes 77 of the connecting rod 75 in the mating surfaces with each other, and holding inside rubber end caps 78 into which the end portions of the connecting rod 75 inserted through the insertion holes 77 are inserted. The rubber end cap 78 has a pair of end portions 79, 79 extending in the left and right directions, and each end portion 79 is inserted into and supported by each of the split portions of the rod receiving portion 76.

Therefore, the inner housing 3 is supported by the rod receiving portions 76 and 76 by the connecting rod 75 penetrating the connecting portion 53 of the bearing holder 50, and can be held so as to swing left and right about the connecting rod 75. The upper and lower ends of the connecting rod 75 serving as a fulcrum are elastically held by rod receiving portions 76, 76 via rubber end caps 78, 78.

On the other hand, a tubular rubber 80 is attached to the outer periphery of the inner case 3 from the tapered portion 30 to the rear portion, and the tubular rubber 80 is interposed between the large diameter portion 10 of the outer case 2 and the inner case 3. Left and right of the cylindrical rubber 80 are arc-shaped flange portions 80a, 80a along the rear surface of the tapered portion 30. Therefore, the entire front circumference of the inner housing 3, which can swing left and right about the connecting rod 75 elastically held by the rubber end cap 78, is elastically held by the outer housing 2 via the cylindrical rubber 80. Here, the hardness of the rubber end cap 78 is lower than that of the cylindrical rubber 80.

Further, a metal fixing ring 81 having the same outer diameter as the large diameter portion 10 is attached to the outside of the cylindrical rubber 80 between the tapered portion 30 and the large diameter portion 10. A pair of flat surface portions 82, 82 are formed on both right and left side surfaces of the fixing ring 81 in the vertical direction.

As shown in fig. 2, 5, and the like, a pair of handle attachment portions 83, 83 are integrally formed on left and right side surfaces at the front end of the outer case 2, and the pair of handle attachment portions 83, 83 extend to the left and right outside and extend forward to the outside of the gear case 5 so as not to contact the outer surfaces of the inner case 3 and the partition plate 69. The handle attachment portion 83 is used for attaching the side handle 25 (fig. 1, 2, and the like), and is formed in a plate shape along a plane defined in the vertical and longitudinal directions, and as shown in fig. 8 (B), the handle attachment portion 83 is screwed to the fixed ring 81 from the left and right outer sides by a pair of upper and lower screws 84, 84 in a state where the inner surfaces thereof are in contact with the plane portions 82, 82 of the fixed ring 81. In this way, the left and right half- shells 2a, 2b of the outer case 2 can be screwed to the fixing ring 81 via the handle attachment portion 83, in addition to being screwed to each other.

(explanation of handle detecting mechanism)

As shown in fig. 5 and 9, a screw hole 85 is formed through each of the handle attachment portions 83 at the front, rear, upper, and lower center portions in the left-right direction, the screw hole 85 being screwed into the screw portion 26 provided at the distal end of the side handle 25 for fixation, and a handle detection mechanism 86 for detecting that the side handle 25 is attached to the screw hole 85 is provided in each of the handle attachment portions 83.

As shown in fig. 10, the handle detection mechanism 86 includes a detection plate 87 and a photo interrupter 88, wherein the detection plate 87 changes a position according to whether or not the side handle 25 is attached; the photo interrupter 88 detects the position of the detection plate 87 when the side handle 25 is mounted and outputs a detection signal to the controller 20, and the controller 20 allows the driving of the brushless motor 4 only when the detection signal of the side handle 25 is obtained.

First, the detection plate 87 is rotatably attached at its front end by a fulcrum pin 90 supported in the vertical direction in a frame portion 89 provided to protrude from the outer surface of the handle attachment portion 83, and is swingable in the horizontal direction at its rear end. A through hole 91 is formed in the detection plate 87 at the rear of the fulcrum pin 90, the through hole 91 being located outside the screw hole 85, the through hole 91 allowing insertion of the screw portion 26 of the side handle 25.

The rear end of the detection plate 87 is bent toward the inside of the handle attachment portion 83, and is inserted into a housing portion 92 of the photointerrupter 88 provided in the handle attachment portion 83, and a light blocking plate 93 is provided at the insertion end. A stopper 94 is provided on the handle attachment portion 83 on the entrance side of the housing portion 92, and the stopper 94 abuts against the light shielding plate 93 when swinging to the outside of the detection plate 87 to regulate the swinging position. A coil spring 95 is housed in the handle attachment portion 83 at the rear of the through hole 91 of the detection plate 87, and the coil spring 95 biases the detection plate 87 to an outer position in contact with the stopper portion 94.

The photointerrupter 88 is configured by providing a light receiving portion 97 on the front surface of a substrate 96 held in the housing portion 92 in the left-right direction on the rear side, and is capable of detecting the light blocking plate 93 of the detection plate 87 inserted into the housing portion 92 by the light receiving portion 97 in a non-contact manner. Here, since the light shielding plate 93 is located outside the light receiving section 97 at a position outside the detection plate 87 and does not shield the light of the light receiving section 97, a non-detection state is achieved in which the detection signal is not output. On the other hand, the detection plate 87 swings inward against the urging force of the coil spring 95, and the light blocking plate 93 blocks the light of the light receiving section 97 at an inner position where the side grip 25 formed on the outer surface of the grip mounting section 83 abuts against the receiving section 98, so that a detection state is achieved in which a detection signal is output. The photointerrupter 88 is provided with a dust cover 88a that covers the light receiving section 97 and a part of the substrate 96, in addition to the slit 88b through which the light blocking plate 93 passes.

On the other hand, the gear housing 5 is fixed by screwing 4 screws 100, 100 into the inner housing 3 via the partition plate 69, wherein the 4 screws 100, 100 penetrate from the front at 4 corners of the gear housing 5 in a front view. A bevel gear 101 is fixedly attached to the front end of the rotating shaft 65 projecting into the gear housing 5, and as shown in fig. 4, the bevel gear 101 meshes with a bevel gear 102 fixedly attached to the upper end of the main shaft 6. The gear housing 5 has exhaust ports 103 and 103 … formed in the front surface thereof and communicates with the inside of the inner housing 3 through a through hole, not shown, provided in the partition plate 69. A shaft lock 104 is provided in front of the exhaust port 103, and the shaft lock 104 can lock the rotation of the main shaft 6 by the bevel gear 102 by a pressing operation.

The main shaft 6 is pivotally supported by upper and lower bearings 106 and 106 held by a gear housing 5 and a bearing box (bearing box)105 assembled to a lower portion of the gear housing 5, and projects downward, and a tip tool 107 (fig. 4) such as a disk-shaped grinding wheel can be attached to a lower end thereof. A grinding wheel cover (not shown) covering the rear half of the tip tool 107 can be attached to the outer periphery of the bearing housing 105.

(description of action of grinder)

In the grinder 1 configured as described above, when the screw portion 26 is screwed into the screw hole 85 through the through hole 91 of the detection plate 87 in either of the left and right handle attachment portions 83, the distal end portion 27 of the side handle 25 holding the screw portion 26 presses the detection plate 87 inward against the biasing force of the coil spring 95, thereby pressing the side handle 25 against the receiving portion 98. The side handle 25 is attached, and the detection plate 87 is swung inward to shield the light receiving portion 97 of the photointerrupter 88 from the light blocking plate 93.

When the switch lever 16 is gripped in a state where the unlock lever 19 is rotated by the finger gripping the rear tube 8 to unlock the lock, the pressing plate 18 presses the plunger 13 as described above to turn on the main switch 12 as described above. Accordingly, the power from the battery pack 11 is supplied to the control circuit board 21 of the controller 20. Here, the control circuit board 21 checks whether or not a detection signal is sent from the photo interrupter 88.

When the switch lever 16 is further gripped, the unlock lever 19 pushes the push button portion 15 of the microswitch 14, and the microswitch 14 is turned on. Then, the control circuit board 21, which obtains the detection signal from the photointerrupter 88 and the on signal of the microswitch 14, supplies the power of the battery pack 11 to the brushless motor 4 to start the brushless motor 4. That is, the microcomputer of the control circuit board 21 obtains the rotation detection signal indicating the position of the permanent magnet 67 of the rotor 33 output from the rotation detection element of the sensor circuit board 38 to acquire the rotation state of the rotor 33, controls on/off of each FET according to the acquired rotation state, and rotates the rotor 33 by sequentially flowing current to each coil 37 of the stator 32. Therefore, since the spindle 6 is rotated (rotated rightward when viewed from above) by the bevel gears 101 and 102 as the rotation shaft 65 is rotated, the polishing work or the like can be performed by the tip tool 107.

Here, since unbalance is present in the rotor 33 of the brushless motor 4 rotating at a high speed and the tip tool 107 attached to the spindle 6, the unbalance becomes a vibration source and transmits vibration to the inner housing 3 and the gear housing 5.

However, since the cylindrical rubber 80 is interposed between the inner case 3 and the outer case 2, vibration is effectively isolated and vibration transmitted to the outer case 2 is reduced. Therefore, the vibration is not easily transmitted to the hand of the author who grips the rear tube portion 8 as the main grip. Further, since the side handle 25 is also attached to the handle attachment portion 83 of the outer case 2 that isolates vibration, vibration is not easily transmitted to the hand of the worker who holds the side handle 25, and vibration can be reduced.

When the brushless motor 4 is started or a load is applied to the rotating tip tool 107, the inner housing 3 is rotated in the left rotational direction (reaction force direction) in a plan view around the coupling rod 75. However, since the tubular rubber 80 is interposed between the inner housing 3 and the outer housing 2, the rotation of the inner housing 3 is damped by the tubular rubber 80, and it is not easy to transmit the reaction force to the outer housing 2 and the side handle 25 attached to the outer housing 2.

On the other hand, when the centrifugal fan 71 is rotated in accordance with the rotation of the rotary shaft 65, the outside air is sucked from the rear air inlet 23, and the outside air passes through the controller 20 from below and moves forward in the outer case 2. Accordingly, the controller 20 and the connection terminal 24 are cooled.

The air flow in the outer housing 2 passes through the main switch 12 and the micro switch 14 to cool them, enters the inner housing 3 through the through hole 52 provided in the bearing holder 50, and passes between the stator 32 and the rotor 33 of the brushless motor 4 to cool the brushless motor 4. Thereafter, the liquid passes from the tapered portion 30, passes through the expanding portion 31, reaches the gear housing 5 via the partition plate 69, and is discharged to the outside from the exhaust port 103.

(effect of the technical means relating to the elastic holding structure of the inner case)

As such, the grinding mill 1 of the above-described type includes: an inner case 3 housing a brushless motor 4 (motor); a main shaft 6 (final output shaft) disposed in front of the brushless motor 4; and an outer housing 2 in which the inner housing 3 is disposed and the outer housing 2 is integrally provided with a rear cylinder 8 (handle), the inner housing 3 and the outer housing 2 are relatively rotatably coupled by a coupling rod 75 (coupling shaft) parallel to the main shaft 6, and the inner housing 3 is held by the outer housing 2 by a cylindrical rubber 80 (front side elastic body) disposed in front of the coupling rod 75. Therefore, the vibration or the reaction force transmitted to the author can be effectively reduced, and the feeling of use or the operability becomes good.

In particular, since the connecting rod 75 is held by the rubber cap 78 (rear side elastic body) in the outer case 2, the vibration transmitted from the connecting rod 75 to the outer case 2 can be effectively reduced.

Further, since the handle attachment portion 83 (attachment portion of the side handle) is provided in the outer case 2, the transmission of vibration or reaction force to the side handle 25 can also be effectively prevented.

Further, since the outer case 2 is a case in which a pair of left and right split cases 2a and 2b are assembled, and the split cases 2a and 2b are fixed to a fixing ring 81 (ring) attached to the outside of the inner case 3 through a tubular rubber 80, the split cases 2a and 2b can be firmly coupled to each other by the fixing ring 81.

On the other hand, since the coupling portion 53 (portion coupled to the coupling shaft) in the inner housing 3 is made of metal, the strength of the coupling portion 53 can be ensured.

Further, since the housing portion of the brushless motor 4 in the inner housing 3 is formed in a cylindrical shape, vibration isolation by the cylindrical rubber 80 can be effectively performed over the entire circumference.

Further, since the electronic components such as the main switch 12, the micro switch 14, the controller 20, and the terminal 24 other than the brushless motor 4 are housed in the outer case 2, the electronic components can be disposed in a state of isolating the vibration at a position away from the brushless motor 4 or the tip tool 107 as a vibration source, and thus, the electronic components can be protected from the vibration.

In addition to this, since the battery pack 11 (battery) serving as a power source is provided in the outer case 2, the mass of the outer case 2 is increased, thereby effectively reducing vibration.

Further, since the hardness of the rubber end cap 78 is set to be lower than that of the cylindrical rubber 80, transmission of the reaction force can be effectively prevented.

In the case of the elastic holding structure according to the aspect of the invention, the coupling shaft may be formed integrally with the coupling portion of the bearing holder, rather than being a separate component from the bearing holder, such as the coupling rod of the above-described aspect. The coupling shaft is not limited to a separate component such as a bearing holder, and may be directly provided in the inner housing. The rear side elastic body elastically holding the coupling shaft may be omitted.

In this embodiment, the structure in which the handle attachment portion is provided on the outer case is not essential, and even in the structure in which the side handle is provided on the gear case as in the conventional art, a certain vibration reduction effect due to the elastic holding of the inner case can be obtained.

The outer case may be formed in an integral cylindrical shape similar to the inner case, instead of the half-open structure as described above. An AC grinder using no battery may be used, or a motor other than a brushless motor may be used.

(Effect of the technical means relating to the handle detecting mechanism)

As such, the grinding machine 1 (power tool) of the above-described aspect includes: an inner case 3 housing a brushless motor 4 (motor); a main shaft 6 (final output shaft) driven by the brushless motor 4; and an outer case 2 in which an inner case 3 is disposed and the outer case 2 is integrated with a rear cylinder 8 (handle), the inner case 3 being held by the outer case 2 via a cylindrical rubber 80 (elastic body), and the outer case 2 being provided with a handle attachment portion 83 (attachment portion of the side handle) and a handle detection mechanism 86 for detecting attachment of the side handle 25. That is, the handle detection mechanism 86 is provided in the outer housing 2, and the outer housing 2 is isolated from the brushless motor 4 and the spindle 6 (tip tool 107) as vibration sources by the cylindrical rubber 80. Accordingly, the grinder 1 having the handle detection mechanism 86 with high durability and reliability without being affected by vibration can be obtained.

In particular, since the handle detection mechanism 86 detects the attachment of the side handle 25 in conjunction with the attachment operation of the side handle 25, no extra operation related to the detection is required even if the handle detection mechanism 86 is provided.

Further, since the handle detection mechanism 86 is provided at a plurality of locations (two locations here), the attachment of the side handle 25 can be individually detected for each of the plurality of handle attachment portions 83.

Since the handle detection mechanisms 86 are provided on the left and right sides of the outer case 2, the attachment of the side handle 25 can be detected in correspondence with the left and right handle attachment portions 83.

In addition, since the inner housing 3 is coupled to the outer housing 2 by the coupling rod 75 (coupling shaft) parallel to the main shaft 6, it is possible to effectively reduce the transmission of the reaction force to the worker when the brushless motor 4 is started or when a load is applied to the tip tool 107.

On the other hand, since the handle detection mechanism 86 is of a non-contact type, a failure or erroneous detection due to foreign matter such as dust is less likely to occur, and improvement in durability and reliability can be expected.

Further, since the lever detection mechanism 86 includes the detection plate 87 (detection member) which abuts against the side lever 25 when the side lever 25 is attached, the detection plate 87 (detection member) is swingable by the front fulcrum pin 90 (fulcrum), the photo interrupter 88 (detection portion) for detecting the detection plate 87 which is swingable by abutting against the side lever 25 is provided at the rear portion of the detection plate 87, and the receiving portion 98 of the side lever 25 is provided between the fulcrum pin 90 and the photo interrupter 88, the detection plate 87 can be reliably swung together with the attaching operation of the side lever 25, and the detection plate 87 can be detected by the photo interrupter 88.

Further, since the photointerrupter 88 is covered with the dust cover 88a, intrusion of foreign matter such as dust can be effectively prevented, and the reliability of detection can be improved.

In the embodiment relating to the handle detection mechanism, the positional relationship between the fulcrum pin and the photointerrupter is not limited to the above-described embodiment, and may be appropriately changed according to the type of the power tool, for example, in the opposite front-back direction to the above-described embodiment, or in the vertical direction.

The detection unit is not limited to the photo interrupter, and other non-contact sensors such as a proximity sensor using a magnet may be used, or contact sensors such as a micro switch and a pressure switch may be used.

In the above-described aspect, the handle detection means is provided for each handle attachment portion, but a plurality of handle attachment portions may be detected by one handle detection means depending on the structure of the handle detection means.

The present invention is not limited to a grinding machine, and may be applied to other power tools such as an angle drill (angle drill) and a sander (sander) as long as the tool has an attachment portion for a side handle. Therefore, in the case of adopting a structure in which the inner housing and the outer housing are coupled by the coupling shaft, the direction of the coupling shaft may be made parallel to the direction of the final output shaft as long as the final output shaft is not directed downward.

In addition, an AC tool not using a battery may be used, and a motor other than the brushless motor may be used.

(description of modified example of elastic holding Structure of inner case)

In the above-described embodiment, both upper and lower ends of the connecting rod 75 are elastically held by the rod receiving portions 76, 76 via the rubber end caps 78, 78. In this case, there is a fear that: when the rubber end caps 78, 78 are pressed against the rod receiving portions 76, the coupling rod 75 is tilted with respect to the vertical direction, and the inner housing 3 is assembled while being tilted. When the inner housing 3 is inclined in this manner, the main shaft 6 is also inclined with respect to the rear cylinder 8, and therefore, an effect of sufficiently reducing vibration and reaction force cannot be obtained. Therefore, a modification for eliminating such an assembly error will be described below. Note that the same components as those of the above-described embodiment are denoted by the same reference numerals, and overlapping description is omitted, and the configuration different from that of the above-described embodiment will be mainly described.

First, an assembly structure of the stator 32 will be described. In the grinder 1A shown in fig. 11 and 12, the stator 32 is inserted from the front of the inner housing 3. As shown in fig. 13 and 15 (a), 4 receiving surface portions 110 and 110 … protruding toward the axial center side are formed on the inner surface of the inner case 3. The receiving surface portions 110 are formed at equal intervals in the circumferential direction and in the front-rear direction. As shown in fig. 15 (B), a locking portion 111 having a triangular cross section is formed at the rear portion of each receiving surface portion 110, and the amount of projection of the locking portion 111 toward the axial center side is larger than the amount of projection toward the front portion.

At the rear portion in the inner housing 3, the bearing holding portion 51 is integrally formed at the axial center of the inner housing 3 by 4 radial coupling plates 51a, 51a … coupled to the inner surface of the inner housing 3.

Here, the stator 32 is inserted from the front of the inner housing 3 by fitting the 4 notches 59 to the 4 locking portions 111, respectively, in phase. Then, as shown in fig. 15 (B), the locking portions 111 are locked to the notches 59 to prevent the stator 32 from rotating and to restrict the backward movement. In this state, the inner surface of each receiving surface portion 110 except the locking portion 111 abuts against the outer surface of the stator core 34 to hold the stator 32.

A pair of slits 112, 112 are formed in the inner housing 3 at vertically symmetrical positions about the axis. The front end of each slit 112 is cut away from the tapered portion 30, and each slit 112 extends rearward. Screw bosses 113 protruding toward the outer surface of the inner housing 3 are formed behind the slits 112 and extending from the front ends of the slits 112.

Further, a fitting projection 114 is formed on the left side surface of the inner case 3. The fitting projection 114 is formed in a band shape having a predetermined width in the upper and lower directions, and extends from the tapered portion 30 to the rear end of the inner housing 3 in the front-rear direction. A pair of inner case side projections 115, 115 extending in the front-rear direction are formed on the left and right outer surfaces of the inner case 3.

A pair of cylindrical portions 116, 116 are formed radially outward above and below the baffle plate 47 assembled to the front side of the stator 32. The small cylindrical portions 116, 116 are fitted in the slits 112, 112 of the inner housing 3 and abut against the screw bosses 113, 113 from the front. Front pressing portions 117, 117 having an arc-shaped cross section are integrally formed on the radially inner side of each small tube portion 116, and the front pressing portions 117, 117 protrude radially inward from the inner peripheral surface of the inner housing 3.

The retainer 47 presses the upper and lower cylindrical portions 116, 116 rearward to positions located forward of the screw bosses 113, 113 via the slits 112, 112. Then, as shown in fig. 11, the front pressing portions 117, 117 are fitted in the fitting concave portions 45, 45 of the front insulator 35 and abut on the front surface of the stator core 34, thereby positioning the stator 32 from the front.

In this positioned state, the cone 30 and the baffle plate 47 form a bowl-shaped flow straightening portion 118 on the rear side of the centrifugal fan 71, and the flow straightening portion 118 is constituted by the cone 30 located on the radially outer side of the inner casing 3 and the baffle plate 47 located on the radially inner side of the inner casing 3.

In the rectifying portion 118, circular holes 119, 119 are formed in front of the screw bosses 113, 113 and the front pressing portions 117, 117 at positions covering the tapered portion 30 and the baffle plate 47. The circular holes 119 and 119 are formed by the semicircular front ends of the slits 112 and 112 formed in the tapered portion 30 in a notch shape in front view, and the semicircular notches 120 and 120 provided on the outer peripheral surface of the baffle plate 47 in front view. A projection 121 is formed on the left side of the front end of the baffle plate 47, and the projection 121 closes a notch formed on the front surface of the tapered part 30 by the fitting projection 114.

In this state, screws 122, 122 penetrating the small cylinder portions 116, 116 from the front through the circular holes 119, 119 are screwed into the screw bosses 113, 113. Then, the front surface of the baffle plate 47 and the front surface of the tapered portion 30 are continuously connected, and the baffle plate 47 is fixed at a position where the rectifying portion 118 is formed. At the same time, the stator 32 is sandwiched and fixed between the retainer 47 and the locking portion 111.

Next, the elastic holding structure of the inner case will be described. At the rear of the inner case 3, the connecting rod 75A is directly held to the rod receiving portions 76A, 76A without a rubber end cap. The connecting rod 75A has a two-step diameter composed of a small diameter portion 125 at the middle and large diameter portions 126 and 126 at the upper and lower ends. The small diameter portion 125 penetrates the through hole 54 of the coupling portion 53 of the inner housing 3. The large- diameter portions 126, 126 protrude upward and downward from the coupling portion 53. Semicircular receiving recesses 127 and 127 for holding the large diameter portion 126 from the left and right are formed in the facing surfaces of the lever receiving portions 76A and 76A.

A rubber sleeve 128 is attached to the outside of the small diameter portion 125. By providing the small diameter portion 125, the thickness of the rubber sleeve 128 in the radial direction can be ensured.

As shown in fig. 13, the rubber sleeve 128 has folded portions 129 and 129 extending toward opposite sides of each other on the outer peripheries of both end portions. A plurality of cutouts 130 and 130 … are provided at equal intervals in the circumferential direction on the outer periphery of each folded-back portion 129.

The rubber sleeve 128 is inserted into the through hole 54 of the coupling portion 53 together with the coupling rod 75A. At this time, the insertion-side folded portion 129 serves as a guide portion when the rubber bush 128 is inserted into the through hole 54. When the connecting rod 75A is inserted through the connecting portion 53, as shown in fig. 14, the rubber bush 128 is positioned by latching the folded portions 129 and 129 at both ends to the upper and lower sides of the connecting portion 53, respectively. Therefore, the inner housing 3 and the coupling rod 75A are elastically coupled by the rubber sleeve 128.

As shown in fig. 15 (a), a pair of groove portions 131, 131 are formed in the upper and lower inner circumferential surfaces of the cylindrical rubber 80 in the front-rear direction, and the screw bosses 113, 113 are fitted into the pair of groove portions 131, 131 in a state where the cylindrical rubber 80 is attached to the outside of the inner housing 3.

A positioning groove 132 is formed in the front-rear direction on the inner surface on the left side of the tubular rubber 80, and the fitting projection 114 is fitted into the positioning groove 132 in a state where the tubular rubber 80 is mounted on the outside of the inner housing 3.

A pair of bulging portions 133, 133 bulging outward in the radial direction are formed at the left and right rear portions of the cylindrical rubber 80. A pair of central slits 134, 134 are formed in the centers of the bulging portions 133, 133 in a notched shape from the rear end of the tubular rubber 80, respectively, and the inner housing side projections 115, 115 are engaged with the pair of central slits 134, 134 in a state where the tubular rubber 80 is attached to the outside of the inner housing 3. A pair of outer slits 135, 135 are formed in the upper and lower parts of each bulging portion 133 in a notched shape from the rear end of the cylindrical rubber 80, and the pair of outer slits 135, 135 are parallel to the central slit 134.

A pair of positioning projections 136, 136 are formed on the upper and lower inner peripheral surfaces of the tubular rubber 80 at positions near the distal ends. The positioning projections 136, 136 are fitted into the circular holes 119, 119 provided in the rectifying portion 118, thereby closing the circular hole 119.

As shown in fig. 13 and 15 (a), a pair of recesses 140, 140 are formed in the right and left inner surfaces of the outer case 2, and the bulging portions 133, 133 of the tubular rubber 80 engage with the pair of recesses 140, 140. A pair of upper and lower outer case side projections 141, 141 to be locked to the outer slits 135, 135 are formed in the upper and lower sides of each recess 140 in the front-rear direction.

In front of each recess 140, a receiving hole 142 is formed in the handle attachment portion 83 so as to penetrate in the left-right direction. Screw cylinders 143, 143 are fitted into the receiving holes 142, and the screw cylinders 143, 143 are provided to project outward from the left and right flat surface portions 82, 82 of the fixed ring 81, respectively. The screw portion 26 of the side handle 25 is screwed to the screw cylinder 143 (fig. 12).

In this modification, the inner housing 3 and the coupling rod 75A are coupled via a rubber sleeve 128 (rear side elastic body). Accordingly, the connecting rod 75A is supported at an appropriate position by the rod receiving portions 76A, 76A without tilting. Therefore, the inner housing 3 is not tilted, and the main shaft 6 is supported at an appropriate position.

In particular, the coupling rod 75A is directly held by the rod receiving portion 76A of the outer case 2. Accordingly, the coupling rod 75A can be supported at an appropriate position while the coupling rod 75A is assembled to the rod receiving portions 76A, 76A.

Further, the inner housing 3 is provided with an inner housing side protrusion 115 (1 st engaging portion), the tubular rubber 80 is provided with a central slit 134 (1 st engaged portion) which engages with the inner housing side protrusion 115 in a rotational direction about the front-rear direction as an axis, the tubular rubber 80 is provided with a bulging portion 133 (2 nd engaging portion), and the outer housing 2 is provided with a recess 140 (2 nd engaged portion) which engages with the bulging portion 133 in the rotational direction. Accordingly, relative play between the outer housing 2 and the inner housing 3 in the circumferential direction (rotational direction) of the tubular rubber 80 can be restricted, and highly reliable positioning can be performed.

Further, an inner housing side protrusion 115 (protrusion) serving as a 1 st engagement portion is provided on an outer surface of the inner housing 3, and a central slit 134 for engaging the inner housing side protrusion 115 is provided in the cylindrical rubber 80. In addition, a bulge 133 (the 2 nd engaging portion) protruding toward the outer surface side of the cylindrical rubber 80 is formed at a portion including the central slit 134. A recess 140 serving as a 2 nd engaged portion is formed in the inner surface of the outer case 2. Accordingly, the outer housing 2 and the inner housing 3 can be positioned in the rotational direction by the cylindrical rubber 80 efficiently.

In this modification, the following modifications and the like may be made without setting the connecting rod to have two diameters: the rubber sleeve is provided with the same diameter in the whole length range, or the folded part of the rubber sleeve is omitted. The rubber sleeve is not limited to one, and a plurality of rubber sleeves having the full length may be used.

In the engaging structure between the inner housing and the cylindrical rubber, the number, shape, and arrangement of the inner housing side projections or the number, shape, and arrangement of the bulging portions may be changed. The number, shape, and arrangement of the central slits or the outer slits may be changed, or through holes or recesses may be provided instead of the slits. The recess and the outer case side projection may be modified in the same manner.

In the above modification, the inner case is provided with the projection (1 st engaging portion) and the cylindrical rubber is provided with the central slit (1 st engaged portion), but the inner surface of the cylindrical rubber may be provided with the 1 st engaging portion such as the projection and the 1 st engaged portion such as the recess and the through hole, on the contrary. Similarly, the tubular rubber is provided with a bulging portion (2 nd engaging portion) and the outer case is provided with a recess (2 nd engaged portion), but conversely, the inner surface of the outer case may be provided with a 2 nd engaging portion such as a projection and the like and the tubular rubber may be provided with a 2 nd engaged portion such as a recess, a through hole and the like.

Claims (13)

1. A grinding machine is characterized in that the grinding machine is provided with a grinding wheel,

comprising an inner housing, a final output shaft and an outer housing, wherein,

the motor is accommodated in the inner shell;

the final output shaft is disposed in front of the motor;

the inner shell is arranged on the inner side of the outer shell, a handle is integrally arranged on the outer shell,

the inner housing and the outer housing are coupled to each other by a coupling shaft parallel to the final output shaft so as to be relatively rotatable,

on the other hand, the inner housing is held by the outer housing via a front-side elastic body disposed in front of the coupling shaft.

2. A grinding mill according to claim 1,

the inner housing and the coupling shaft are coupled by a rear side elastic body.

3. A grinding mill according to claim 1 or 2,

the coupling shaft is directly held to the outer housing.

4. A grinding mill according to any one of claims 1 to 3,

a 1 st engaging portion is provided on one of the inner case and the front side elastic body, a 1 st engaged portion is provided on the other of the inner case and the front side elastic body, and the 1 st engaged portion is engaged with the 1 st engaging portion in a rotational direction having a front-rear direction as an axis,

a 2 nd engaging portion is provided on one of the front side elastic body and the outer case, and a 2 nd engaged portion is provided on the other of the front side elastic body and the outer case, the 2 nd engaged portion engaging with the 2 nd engaging portion in the rotation direction.

5. A grinding mill according to claim 4,

a projection serving as the 1 st engaging portion is provided on an outer surface of the inner case,

the front side elastic body is provided with the 1 st engaged part engaged with the protrusion, and a part including the 1 st engaged part is formed on the 2 nd engaging part protruding to the outer surface side of the front side elastic body,

a recess serving as the 2 nd engaged portion is formed in an inner surface of the outer case.

6. A grinding mill according to claim 1,

the coupling shaft is held within the outer case by a rear side elastic body.

7. A grinding mill according to any one of claims 1 to 6,

the outer shell is provided with an installation part of a side handle.

8. A grinding mill according to any one of claims 1 to 7,

the outer case is formed by assembling a pair of left and right split cases, and each of the split cases is fixed to a ring attached to the outside of the inner case by the front-side elastic body.

9. A grinding mill according to any one of claims 1 to 8,

the coupling portion of the inner housing coupled to the coupling shaft is made of metal.

10. A grinding mill according to any one of claims 1 to 9,

the housing portion of the motor in the inner case is cylindrical.

11. A grinding mill according to any one of claims 1 to 10,

electronic components other than the motor are housed in the outer case.

12. A grinding mill according to any one of claims 1 to 11,

a battery that becomes a power source is provided in the outer case.

13. A grinding mill according to any one of claims 1 to 12,

the rear side elastic body has a lower hardness than the front side elastic body.

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