JP2016016469A - Rotary tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotary tool which maintains the sealability of a seal member for a long period even when axial backlash occurs in a spindle.SOLUTION: A cutter 1 includes: a housing; a motor 6 housed in the housing; a spindle 8 which is partially housed in the housing and rotated by driving of the motor 6, the spindle 8 in which a tip tool T may be attached to an end part protruding from the housing; an O ring 38 which is attached to an exterior part of the spindle 8 and seals a gap S, which is formed in an axial direction of the spindle 8, between a front wall part 36 of a bearing retainer 24 and an inner flange 31 of the spindle 8; and a wave washer 39 which biases the spindle 8 to the side such that the spindle 8 presses the O ring 38 in the axial direction.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a rotary tool such as a cutter for mounting a tip tool on a spindle that is rotated by a motor.

In a rotary tool such as a cutter, the rotation of the output shaft of a motor is transmitted to a spindle separate from the output shaft via a gear, and a disk-shaped tip tool mounted on the spindle is rotated to perform operations such as cutting ( For example, refer nonpatent literature 1). FIG. 4 is an enlarged view of a spindle portion of a conventional cutter 50, in which a front output shaft 52 of a motor housed in a front housing 51 protrudes and a spindle 53 parallel to the output shaft 52 is pivotally supported. The pinion 54 fixed to the tip of the output shaft 52 is engaged with a gear 55 fixed to the rear portion of the spindle 53. The spindle 53 is rotatably supported by a front bearing 57 held by a bearing retainer 56 assembled to the housing 51 from the front and a rear bearing 59 held by a recess 58 formed in the housing 51. A front end tool T such as a diamond wheel can be attached to the front end protruding from the bearing retainer 56 by an inner flange 60, an outer flange 61 and a bolt 62.
Here, an O-ring 63 is attached to the spindle 53 between the bearing retainer 56 and the inner flange 60 so that dust generated by cutting work or the like does not enter the bearing 57 side from between the spindle 53 and the bearing retainer 56. Exterior.

Makita general catalog 2014-4, page 68, rechargeable cutter CC300DW, etc. [Search June 30, 2014], Internet <URL: http://www.makita.co.jp/product/ecatalog/sougou/index .html # 68>

  In such a cutter 50, the spindle 53 may be slightly rattled in the axial direction due to component tolerances, etc., so that the bearing retainer 56 and the inner flange 60 in which the O-ring 63 is interposed by this rattling. When the clearance S changes, and the clearance S increases, the sealing performance by the O-ring 63 decreases, and when it decreases, the O-ring 63 is excessively pressed to promote deterioration such as wear.

  Accordingly, an object of the present invention is to provide a rotary tool that can extend the sealing performance of a sealing member such as an O-ring even when the spindle has an axial backlash.

In order to achieve the above object, a first aspect of the present invention is directed to a housing, a motor housed in the housing, and an end projecting from the housing that is partly housed in the housing and rotated by driving of the motor. A spindle that can be fitted with a tip tool, a seal member that is externally mounted on the spindle and seals the clearance in the axial direction of the spindle between the housing and the spindle, and the spindle is attached to the side that presses the seal member in the axial direction. Biasing means for biasing.
According to a second aspect of the present invention, in the configuration of the first aspect, the seal member is an O-ring.
According to a third aspect of the present invention, in the configuration of the first or second aspect, the housing holds a bearing for rotatably supporting the spindle, and the urging means is arranged between the housing and the bearing in the holding portion of the bearing. It is a wave washer arrange | positioned between.
According to a fourth aspect of the present invention, in the configuration of the third aspect, the bearing is a rolling bearing in which a rolling element is disposed between the inner ring and the outer ring, and the wave washer is in contact with the outer ring and the spindle via the bearing. It is characterized by energizing.
In order to achieve the above object, a fifth aspect of the present invention is directed to a housing, a motor housed in the housing, and an end projecting from the housing that is partially housed in the housing and rotated by driving of the motor. A spindle that can be fitted with a tip tool, a seal member that is externally mounted on the spindle and seals the clearance in the axial direction of the spindle between the housing and the spindle, and the clearance between the housing and the spindle is kept constant. And maintaining means.
According to a sixth aspect of the invention, in the configuration of the fifth aspect, the maintaining means is an urging means for urging the spindle toward the side pressing the seal member in the axial direction.
In order to achieve the above-mentioned object, the invention according to claim 7 fixes the rotating part, a fixing part holding the rotating part, a seal member disposed between the rotating part and the fixing part, and fixing the rotating part. It has an urging means for urging toward the part.

According to the first, fifth, and seventh aspects of the present invention, even when the spindle (rotating portion) is shaky in the axial direction, the gap between the housing (fixed portion) and the spindle is kept constant by the biasing means. Therefore, the sealing performance by a sealing member such as an O-ring can be prolonged.
According to the second aspect of the present invention, in addition to the effect of the first aspect, since the seal member is an O-ring, a seal member suitable for sealing between the housing and the spindle can be used.
According to the third aspect of the present invention, in addition to the effect of the first or second aspect, the urging means can be employed in a space-saving and low-cost manner because the urging means is a wave washer.
According to the fourth aspect of the invention, in addition to the effect of the third aspect, the spindle can be easily and rationally biased by utilizing the outer ring of the rolling bearing.
According to the sixth aspect of the invention, in addition to the effect of the fifth aspect, the clearance can be easily maintained by urging the spindle.

It is a longitudinal cross-sectional view of a cutter. It is an enlarged view of a spindle part. It is a perspective view of a wave washer. It is an enlarged view of the spindle part of the conventional cutter.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a longitudinal sectional view of a cutter as an example of a rotary tool. The cutter 1 includes a motor 6 and a spindle 8 on a rectangular base 2 in plan view, and a front end of the spindle 8 (the left side in FIG. And a main body 3 on which a disc-shaped tip tool T (diamond wheel or the like) can be mounted. The main body 3 is constructed by assembling a front housing 5 holding a spindle 8 from the rear with a plurality of screws 9 in front of a motor housing 4 in which the motor 6 is accommodated forward, and is not shown above the motor housing 4. A handle 10 having a built-in switch and a battery pack serving as a power source is connected. The front housing 5 includes a cover portion 11 that covers the upper portion of the tip tool T attached to the spindle 8 along the circumferential direction, and the lower portion of the tip tool T is below the base 2 in a state of being attached to the spindle 8. It protrudes to.

The base 2 and the main body 3 are rotatably connected by shafts (not shown) provided on the left and right sides of the front housing 5, and the right shaft is along an arcuate depth guide (not shown) erected from the base 2. It is slidable in the vertical direction, and can be fixed at an arbitrary position in the depth guide by a knob screw provided on the shaft. Therefore, the protrusion amount (cutting amount) of the tip tool T from the base 2 can be adjusted by the fixed position.
Further, the main body 3 is slidable along the arcuate groove of a top guide (not shown) connected to the left side of the base 2 at the rear portion of the left shaft. It can be fixed at any position. Therefore, the angle of the tip tool T with respect to the base 2 can be adjusted.

  The motor 6 is a commutator motor including a stator 12 held in the motor housing 4 and a rotor 13 that passes through the stator 12 and is provided with a commutator 14 at the rear. The output shaft 7 provided at the front end is supported by a bearing 15 held at the rear end of the front housing 5 and supported by a bearing 16 held at the rear inner surface of the motor housing 4. A pinion 17 is fixed to the tip protruding into the front housing 5. A centrifugal fan 18 is fixed to the rear side of the bearing 15, and a baffle plate 19 that surrounds the outside of the centrifugal fan 18 and guides the air flow forward is provided at the front end of the motor housing 4. Therefore, the air sucked from the air inlet (not shown) provided on the rear surface of the motor housing 4 by the rotation of the centrifugal fan 18 is cooled by passing through the motor 6 and then guided to the front housing 5 side by the baffle plate 19. Not exhausted from the exhaust port.

  As shown in FIG. 2, the spindle 8 is a shaft body in which the outer diameter gradually increases from the rear toward the front in the order of the small diameter portion 20, the medium diameter portion 21, and the large diameter portion 22. Between the large diameter portion 22, a flange 23 having a diameter larger than that of the large diameter portion 22 is provided. A bearing retainer 24 through which the spindle 8 passes is assembled to the front housing 5 below the output shaft 7 from the front, and a bearing 25 held in the bearing retainer 24 is fixed to the medium diameter portion 21 of the spindle 8. Yes. On the other hand, a bearing 27 held in a recess 26 formed on the rear inner surface of the front housing 5 is fixed to the small diameter portion 20, and the spindle 8 is parallel to the output shaft 7 in front of the output shaft 7. The large diameter portion 22 and the flange 23 are projected forward from the bearing retainer 24 by being supported. A gear 28 is fixed to the middle diameter portion 21 behind the bearing 25 and meshes with the pinion 17 of the output shaft 7.

The front bearing 25 is located at the front end of the medium diameter portion 21, and the inner ring 25 a is brought into contact with the rear surface of the flange 23, and the outer ring 25 b is brought into sliding contact with the inner peripheral surface of the bearing retainer 24. The gear 28 is restricted from moving rearward by a retaining ring 30 provided at the rear end of the middle diameter portion 21 in a state where the gear 28 is in contact with the rear surface of the washer 29 that is in contact with the rear surface of the inner ring 25a. Therefore, the bearing 25, the washer 29, and the gear 28 are integrated with the spindle 8 in the rotational direction in a state where movement in the front-rear direction is restricted between the flange 23 and the retaining ring 30.
The rear bearing 27 is located at the front end of the small-diameter portion 20 so that the inner ring 27 a is in contact with the rear surface of the medium-diameter portion 21 and the outer ring 27 b is in sliding contact with the inner peripheral surface of the recess 26.

  On the other hand, a tip tool T can be mounted on the large diameter portion 22 of the spindle 8 by means of a disc-shaped inner flange 31 and an outer flange 32. That is, the center hole of the tip tool T is fitted to the cylindrical portion 33 in a state where the cylindrical portion 33 provided at the center of the inner flange 31 is fitted to the large diameter portion 22 and the rear surface is brought into contact with the flange 23. Then, the outer tool 32 is covered from the front, and a bolt 34 penetrating through the centers of the outer flange 32 and the inner flange 31 is screwed into a screw hole 35 provided in the shaft center of the spindle 8, so that the tip tool T becomes an inner flange. 31 and the outer flange 32 so as to be fixed integrally with the spindle 8.

  The bearing retainer 24 rises forward on the outer side of the inner flange 31 and the disk-shaped front wall portion 36 that extends between the front bearing 25 and the inner flange 31 and extends to the inner periphery of the bearing retainer 24 close to the flange 23 of the spindle 8. And a rising portion 37 that overlaps in the state of being close to the outer periphery of the inner flange 31. Among these, the front surface of the front wall portion 36 is a tapered portion 36a that becomes thinner as the intermediate portion in the radial direction goes to the center. It is getting bigger. In the gap S between the inner flange 31 and the thin wall portion 36b of the front wall portion 36, the flange 23 is covered with an O-ring 38 as a seal member to seal between the inner flange 31 and the front wall portion 36. Yes.

A wave washer 39 as an urging means is provided behind the front wall portion 36 and between the front bearing 25. The wave washer 39 is a ring body formed in a waveform along the circumferential direction as shown in FIG. 3, and in the interposed state between the front wall portion 36 and the bearing 25, the wave washer 39 is compressed in the axial direction and is outer ring 25b. And an elastic force that urges the spindle 8 backward via the bearing 25 is generated. Therefore, the spindle 8 is pressed to the rear position where the rear bearing 27 abuts against the bottom surface of the recess 26 by the elastic force of the wave washer 39 even if the shading occurs in the axial direction due to component tolerance. As a result, the gap S between the inner flange 31 and the thin wall portion 36b of the front wall portion 36 is kept constant, and the O-ring 38 is always compressed and deformed in the same state to seal between the inner flange 31 and the front wall portion 39. Will do.
The wave washer 39 is regarded as a maintaining means for maintaining the gap S between the inner flange 31 and the thin portion 36b of the front wall portion 36 constant by urging the spindle 8 backward to suppress rattling. You can also.

In the cutter 1 configured as described above, when the base 2 is set on the workpiece, when a trigger (not shown) provided on the handle 10 is pushed in to turn on the switch in the handle 10, the battery pack The motor 6 is energized to rotate the rotor 13, and the reduced speed rotation is transmitted to the spindle 8 from the pinion 17 of the output shaft 7 through the gear 28. Therefore, the tip tool T integrated with the spindle 8 rotates, and the workpiece can be cut.
At this time, dust generated by cutting or the like circulates in the cover portion 11 along the rotation direction of the tip tool T and is discharged from the side. However, dust may circulate to the rear side of the tip tool T. In addition, since the rising portion 37 of the bearing retainer 24 overlaps the outer periphery of the inner flange 31, dust hardly enters between the inner flange 31 and the front wall portion 36 of the bearing retainer 24. Even if it has entered, the gap between the inner flange 31 and the front wall portion 36 is bent in an L shape in the longitudinal section by the rising portion 37, so that it is difficult to reach the spindle 8 side.

  Even if dust reaches the spindle 8 side, the O-ring 38 is interposed between the inner flange 31 and the front wall portion 36 of the bearing retainer 24. There is almost no possibility of entering beyond the bearing 25 behind it. In particular, since the spindle 8 is urged rearward by the wave washer 39 and the shakiness in the axial direction is suppressed, the gap S between the inner flange 31 and the thin portion 36b of the front wall portion 36 is kept constant. The sealing performance is preferably maintained by the O-ring 38 that compressively deforms in the same state.

  Thus, according to the cutter 1 of the said form, the housing (motor housing 4 and the front housing 5) as a fixing | fixed part, the motor 6 accommodated in a housing, and a part are accommodated in the front housing 5. FIG. A spindle 8 as a rotating part that can be mounted by attaching a tip tool T to an end protruding from the front housing 5 by driving the motor 6, and a front wall 36 of the bearing retainer 24 and the spindle 8 are mounted on the spindle 8. An O-ring 38 that seals the axial clearance S of the spindle 8 between the inner flange 31 and a biasing means (wave washer 39) that biases the spindle 8 toward the side that presses the O-ring 38 in the axial direction. Or, by having a maintaining means (wave washer 39) for maintaining the gap S constant, the spindle 8 may rattle in the axial direction due to component tolerances or the like. Even, since the gap S is maintained constant by the wave washer 39, it is possible to preserve the sealing property of the O-ring 38.

In particular, here, since the seal member is the O-ring 38, a seal member suitable for sealing between the front wall portion 36 and the inner flange 31 can be used.
Further, since the urging means is the wave washer 39 disposed between the front wall portion 36 and the bearing 25 in the holding portion (bearing retainer 24) of the bearing 25, the urging means is space-saving and low-cost. Can be adopted.
Further, since the wave washer 39 is in contact with the outer ring 25b of the bearing 25 which is a rolling bearing and urges the spindle 8 through the bearing 25, the spindle 8 can be simply and rationally utilized using the outer ring 25b of the rolling bearing. Can be energized.

The seal member is not limited to the O-ring, and other types such as an X-ring can be used.
In addition to the wave washer, the urging means may be a disc spring, a coil spring, a leaf spring, or an elastic material such as rubber. The installation position of the urging means is not limited to the inside of the bearing retainer and can be changed if the spindle can be urged. Therefore, the urging means is not limited to compression urging, and for example, it can be considered that the urging means is pulled and urged by a coil spring or the like that is stretched between the rear end of the spindle and the housing.
On the other hand, the setting of the outer diameter of the spindle and the presence or absence of a flange can be selected as appropriate. In the housing, the taper portion and the thin portion of the bearing retainer are not essential, and the bearing retainer may be formed integrally with the front housing or the like.

The maintaining means is not limited to the case where an urging means such as a spring is employed, and the seal member is engaged with the spindle or a bearing integrated with the spindle on the housing side to restrict the movement of the spindle in the axial direction. It is also conceivable to provide an engaging portion that keeps this gap constant.
In addition, the rotary tool is not limited to the cutter, and if it has a structure that seals the gap in the axial direction between the housing and the spindle with a sealing member, a portable device such as a circular saw or a grinder whose spindle is orthogonal to the motor output shaft is used. The present invention can be applied to a stationary rotary tool such as a desktop circular saw as well as a rotary tool of a mold.

  Further, the sealing member does not necessarily need to be externally contacted with the spindle or the rotating part. For example, in the above embodiment, the O-ring may be held by the bearing retainer and separated from the spindle. Further, the seal member may be held by the inner flange instead of the bearing retainer.

  1 .... Cutter, 2 .... Base, 3 .... Main body, 4 .... Motor housing, 5 .... Front housing, 6 .... Motor, 7 .... Output shaft, 8 .... Spindle, 11 .... Cover part, 15. , 16, 25, 27 .. Bearing, 20. .. Small diameter part, 21 .. Medium diameter part, 22. .. Large diameter part, 23 .. Flange, 24 .. Bearing retainer, 25a .. Inner ring, 25b .. Outer ring , 26 .. Recessed part, 28 .. Gear, 31 .. Inner flange, 32 .. Outer flange, 36 .. Front wall part, 36 a .. Tapered part, 36 b .. Thin wall part, 37.・ ・ O-ring, 39 ・ ・ Wave washer.

Claims (7)

A housing;
A motor housed in the housing;
A spindle partly housed in the housing, rotated by driving of the motor, and capable of mounting a tip tool on an end protruding from the housing;
A seal member that is externally mounted on the spindle and seals the axial gap of the spindle between the housing and the spindle;
An urging means for urging the spindle toward the side pressing the seal member in the axial direction.   The rotary tool according to claim 1, wherein the seal member is an O-ring. The housing holds a bearing for rotatably supporting the spindle,
The rotary tool according to claim 1 or 2, wherein the biasing means is a wave washer disposed between the housing and the bearing in a holding portion of the bearing.   The bearing is a rolling bearing in which a rolling element is disposed between an inner ring and an outer ring, and the wave washer contacts the outer ring and biases the spindle via the bearing. 3. The rotary tool according to 3. A housing;
A motor housed in the housing;
A spindle partly housed in the housing, rotated by driving of the motor, and capable of mounting a tip tool on an end protruding from the housing;
A seal member that is externally mounted on the spindle and seals the axial gap of the spindle between the housing and the spindle;
A rotating tool comprising: a maintaining means for maintaining the gap between the housing and the spindle constant.   6. The rotary tool according to claim 5, wherein the maintaining means is an urging means for urging the spindle toward the side pressing the seal member in the axial direction.   A rotating portion; a fixing portion that holds the rotating portion; a seal member that is disposed between the rotating portion and the fixing portion; and a biasing unit that biases the rotating portion toward the fixing portion. A rotary tool comprising:

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