JP2011056621A - Hand power tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a device in size while maintaining a conventional preferable function such as a dust-prevention. <P>SOLUTION: A hand power tool 10 includes a casing 12 for accommodating a motor 31 therein and a rotating tool 21 rotated and driven by receiving a rotating and driving force from the motor 31. The casing 12 includes a bearing support 61 provided with a bearing 18 for supporting the motor shaft 32 of the motor 31. The bearing support 61 has a small through-hole 61a having a smaller diameter than an outside diameter of the bearing inside the bearing support into which the motor shaft 32 is inserted and a large through-hole 61b formed and opened outside the casing 12 from the small through-hole 61a with a diameter larger than the outside diameter of the bearing. Thus, the bearing 18 is inserted from outside the casing 12. A dust-proof labyrinth 71 is formed inside the bearing support 61. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a hand-held power tool, and more particularly to a hand-held power tool in which an outer peripheral portion of a motor storage portion in a casing is configured as a grip portion that is gripped by an operator.

  Conventionally, electric tools using a motor such as a hand grinder or a hand drill as a drive source are known. In this type of electric tool, a bearing is used to rotatably hold the motor shaft of the motor, but a dust-proof structure should be added to prevent dust from entering the bearing. Was done. For example, in the electric power tool described in Patent Document 1 below, a technique for preventing dust from entering the bearing by forming a labyrinth structure on the outer side of the bearing has been proposed (in this case, "The outer side of the bearing" refers to the opposite side of the bearing from the motor installation side).

JP-A-8-182242

  In the technique described in Patent Document 1, a labyrinth structure is formed by three components, that is, a dust-proof ring, a bearing side surface, and an end portion of a bearing cap, and this labyrinth structure is formed by a bearing installed on a motor shaft. It was formed on the outer side (that is, the non-motor installation side in the bearing). Therefore, the labyrinth structure disclosed in Patent Document 1 requires a relatively large installation area.

  On the other hand, in the recent industry, in particular, in order to improve the operability of a hand-held power tool in which the outer peripheral portion of the motor housing portion in the casing is configured as a gripping portion that receives gripping from the operator, There has been a demand for a more compact outer shape. However, in the conventional technique represented by the above-mentioned Patent Document 1, it has been very difficult to realize a compact apparatus while maintaining a function such as dustproof for suitably operating the electric tool. Therefore, there has been a demand for the creation of a new technology that can realize further downsizing of the device while maintaining the function as an electric tool.

  The present invention has been made in view of the above-described problems, and the object thereof is to make the apparatus more compact while maintaining a suitable function such as dustproof that a hand-held power tool has conventionally had. It is to provide a new technology that can.

  The present invention will be described below. In addition, in order to make an understanding of this invention easy, the reference number of an accompanying drawing is attached in parenthesis writing, However, This invention is not limited to the form of illustration by it.

  A hand-held power tool (10) according to the present invention includes a casing (12) that houses a motor (31) therein, and a rotary tool (21) that rotates by receiving a rotational driving force from the motor (31). The motor (31) housing portion of the casing (12) is a hand-held power tool (10) configured as a grip portion that receives grip from an operator, and the casing (12) Comprises a bearing support part (61) for installing a bearing (18) for supporting the motor shaft (32) of the motor (31), and the bearing support part (61) comprises the motor shaft (32). A small through hole (61a) formed with a diameter smaller than the outer diameter of the bearing on the inner side into which the shaft is inserted, and from the small through hole (61a) toward the outer side of the casing (12) The bearing (18) is inserted from the outer side of the casing (12) by being formed to have a large through hole (61b) that is open and formed with a diameter larger than the outer diameter of the alling. Further, a dust-proof labyrinth (71) is formed on the inner side of the bearing support (61).

  In the hand-held power tool (10) according to the present invention, the dust-proof labyrinth (71) can be formed so as to be within a region of the bearing outer diameter or less.

  ADVANTAGE OF THE INVENTION According to this invention, the new technique which can make an apparatus more compact can be provided, maintaining the suitable functions, such as dust prevention which a hand-held power tool has conventionally.

It is an external appearance right view of the hand-held power tool which concerns on this embodiment. It is an external appearance front view of the handheld power tool concerning this embodiment. It is an external appearance rear view of the hand-held power tool which concerns on this embodiment. It is a figure at the time of seeing the hand-held power tool concerning this embodiment from the bottom, and shows the state where a whetstone as a rotary tool, a safety cover, a part of member which constitutes a housing, etc. were removed. It is a longitudinal cross-section right view for demonstrating the internal structure of the hand-held power tool which concerns on this embodiment. It is a partial expanded sectional view which shows the detail of the A section in FIG.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments for carrying out the invention will be described with reference to the drawings. The following embodiments do not limit the invention according to each claim, and all combinations of features described in the embodiments are not necessarily essential to the solution means of the invention. .

  FIG. 1 is an external right side view of a hand-held power tool according to the present embodiment, FIG. 2 is an external front view of the hand-held power tool according to the present embodiment, and FIG. 3 is related to the present embodiment. It is an external appearance rear view of a hand-held power tool. FIG. 4 is a view of the hand-held power tool according to the present embodiment when viewed from the bottom. A grindstone 21 as a rotary tool, a safety cover 22, a part of members constituting the housing 11, and the like are removed. Shows the state. 5 is a right side view of the vertical cross section for explaining the internal structure of the hand-held power tool according to the present embodiment, and FIG. 6 is a partial enlarged cross sectional view showing details of a portion A in FIG. .

  As shown in FIGS. 1 to 6, the hand-held power tool 10 according to the present embodiment is configured as a hand-held portable grinder and is substantially cylindrical so that the operator can hold it with one hand. And a disc-shaped grindstone 21 which is a rotary tool for performing grinding work.

  The housing 11 includes a motor case 12 serving as a casing that houses a motor 31 serving as a driving source, and a plurality of gear groups for receiving the rotational driving force from the motor 31 and transmitting the rotational driving force to the grindstone 21. And a tail cover 14 serving as a cover member in which a power cord for supplying power to the motor 31 and a power supply device such as a switch box are accommodated. Yes.

  The motor case 12 is made of a metal member such as a resin or an aluminum alloy, and the outer peripheral portion of the motor storage portion in the motor case 12 is a member configured as a grip portion that receives grip from the operator. The outer shape of the motor case 12 is formed in a substantially cylindrical shape so that the operator can easily hold it, and an uneven shape 12a for preventing slipping is formed on the surface thereof.

  The gear case 13 connected to the front side of the motor case 12 is made of a metal member such as an aluminum alloy. And the grindstone 21 as a rotary tool which will perform grinding work is arrange | positioned in the lower part of this gear case 13, and the chip etc. do not scatter to an operator on the back side of the grindstone 21. In order to achieve this, a safety cover 22 is installed.

  The tail cover 14 is made of resin. The tail cover 14 is configured so that it can be divided into upper and lower parts. For example, as shown in FIG. 4, by removing the halved member on the bottom side, maintenance of the power supply device installed inside can be performed. It is like that.

  As shown in FIG. 5 depicting the internal structure of the hand-held power tool 10, a motor 31 serving as a drive source for driving the grindstone 21 is accommodated in the motor case 12. The shaft center of the motor shaft 32 is arranged so as to substantially overlap the shaft center of the substantially cylindrical motor case 12. A front end portion 32 a of the motor shaft 32 protrudes from the motor case 12 into the gear case 13 and is supported by a front bearing 17 fixed at a position sandwiched between the motor case 12 and the gear case 13. On the other hand, the rear end portion 32 b of the motor shaft 32 is supported by the rear bearing 18 at the rear portion of the motor case 12. Therefore, the motor shaft 32 is configured to be able to rotate at high speed by supporting both end portions 32a and 32b by the front and rear bearings 17 and 18.

  A cooling fan 19 is installed on the side of the front end portion 32 a of the motor shaft 32 so as to be accommodated in the motor case 12. The cooling fan 19 is arranged in the motor case 12 and plays a role of passing cooling air through the central portion of the motor case 12. Accordingly, when the cooling fan 19 rotates together with the motor shaft 32, the outside air is taken into the motor case 12, cools the motor 31 and the like through the gap in the motor case 12, and is then discharged outside the apparatus.

  A commutator 33 is attached to the rear end portion 32 b of the motor shaft 32, and a brush (not shown) attached to the motor case 12 is in contact with the commutator 33. The commutator 33 and the brush (not shown) are also cooled by the cooling air introduced by the action of the cooling fan 19 described above.

  A small bevel gear 23 fixed to the front end portion 32 a of the motor shaft 32 and a large bevel gear 24 that meshes with the small bevel gear 23 are accommodated in the gear case 13. The bevel gear 24 is fixed to a drive shaft 27 that is vertically supported in the gear case 13 via bearings 25 and 26, and the drive shaft 27 protrudes below the gear case 13, and a grindstone is formed at the protruding portion. 21 is detachably fixed. The members such as the small bevel gear 23, the large bevel gear 24, and the drive shaft 27 function as a driving force transmission unit, so that when the motor 31 rotates, the rotational driving force is transmitted from the motor shaft 32 to the small bevel gear 23 and the large umbrella Since it is transmitted to the gear 24 and finally the grindstone 21 rotates via the drive shaft 27, it is possible to perform grinding on the workpiece.

  Further, the tail cover 14 houses an on / off switch 28 and other power supply devices. When the operator switches the on / off switch 28, the motor 31 rotates or stops, and the hand-held electric motor is operated. The tool 10 can be operated. That is, when the operator holds the motor case 12 with one hand and turns on the on / off switch 28 with the finger of the other hand, the motor 31 rotates and moves from the motor shaft 32 to the small bevel gear 23 and the large bevel gear 24. And the power is transmitted, and the grindstone 21 rotates. Thereby, it can grind with respect to a to-be-processed target object. At this time, since the cooling fan 19 rotates simultaneously with the rotation of the motor shaft 32, the outside air is taken into the motor case 12. The outside air passes through the gap between the inner wall surface of the motor case 12 and the motor 31 to cool the heat sources such as the motor 31, the commutator 33, and a brush (not shown), and then passes through the motor case 12 to the outside of the machine. Therefore, safe and stable operation of the hand-held power tool 10 is realized. When the grinding operation is completed and the operator turns off the on / off switch 28, the motor 31 stops and the grindstone 21 stops rotating.

  The basic configuration of the handheld power tool 10 according to the present embodiment has been described above, but the handheld power tool 10 according to the present embodiment has further significant features. Therefore, the configuration of the hand-held power tool 10 according to the present embodiment will be further described with reference to FIG.

  In the present embodiment, the rear bearing 18 that supports the rear end portion 32 b of the motor shaft 32 is installed via the bearing rubber 29 with respect to the bearing support portion 61 formed at the rear portion of the motor case 12. The bearing support portion 61 is formed as a through-hole penetrating inward and outward of the motor case 12. More specifically, the bearing support portion 61 is an inner portion into which the rear end portion 32 b of the motor shaft 32 is inserted. On the side (front side), there is a small hole 61a formed with a diameter smaller than the outer diameter of the rear bearing 18, and the rear part is directed from the small hole 61a toward the outer side (rear side) of the motor case 12. It is formed with a large through hole 61 b that is open and formed with a diameter larger than the outer diameter of the bearing 18. In other words, in the present embodiment, the rear bearing 18 is installed in the motor case 12 by being inserted into the large through hole 61b of the bearing support portion 61 from the outer side (back side) of the motor case 12. The rear end portion 32b of the motor shaft 32 that passes through the small through hole 61a from the inner side (front side) of the motor case 12 and projects into the large through hole 61b is in the large through hole 61b of the bearing support portion 61. It is configured to be supported by the installed rear bearing 18.

  The bearing rubber 29 installed between the rear bearing 18 and the large through hole 61b is a member provided for absorbing vibration, and the motor shaft 32 by the rear bearing 18 installed in the large through hole 61b. The rear end 32b is supported stably.

  Further, as described above, the tail cover 14 as a cover member is connected to the outer side (back side) of the motor case 12. Therefore, since the outer side (back side) of the large through hole 61b into which the rear bearing 18 is inserted is held by the tail cover 14, a reliable fixed state of the rear bearing 18 is maintained. Become.

  Furthermore, in this embodiment, a dust-proof labyrinth 71 is formed on the inner side (front side) of the bearing support portion 61. The dust-proof labyrinth 71 includes a convex shape 72 formed from the vicinity of the portion where the small hole 61a is formed in the motor case 12 toward the inner side (front side) of the motor case 12, and the inner side (front side) of the convex shape 72. This is a structure formed by the cooperation of the concave shape 73a of the dustproof collar 73 disposed on the side).

  This structure will be described more specifically. The dust-proof collar 73 is a member that can be accommodated in a relatively narrow space formed on the inner side (front side) of the convex shape 72 and faces the convex shape 72 in the installed state. It is a member which has the concave shape 73a arrange | positioned. On the other hand, the convex shape 72 formed in the motor case 12 is formed at an intermediate position between the inner diameter of the small through hole 61a and the inner diameter of the large through hole 61b. Therefore, in the hand-held power tool 10 according to the present embodiment, the formation range of the dust-proof labyrinth 71 can be configured to fall within a region equal to or less than the outer diameter of the rear bearing 18, and by this configuration, It is possible to realize a more compact handheld power tool 10 while maintaining a suitable function such as dust prevention. Such an effect is that the rear bearing 18 is inserted from the outer side (rear side) of the motor case 12 and the dust-proof labyrinth 71 is formed on the inner side (front side) of the rear bearing 18 installation position. It became feasible.

  As mentioned above, although preferred embodiment of this invention was described, the technical scope of this invention is not limited to the range as described in the said embodiment. Various modifications or improvements can be added to the embodiment.

  For example, although the above-described embodiment has been described by way of example as being configured as a hand-held portable grinder, the hand-held power tool according to the present invention can be any type of hand-held portable tool such as a hand-held portable drill. It is possible to apply to an electric tool.

  In the above-described embodiment, the dust-proof labyrinth 71 applied to the rear bearing 18 that supports the rear end portion 32b of the motor shaft 32 has been described. However, the front bearing that supports the front end portion of the motor shaft and the other bearings are described. It is also possible to apply the dustproof labyrinth of the present invention to the member.

  Furthermore, in the above-described embodiment, the case where the convex shape 72 is formed with respect to the motor case 12 and the concave shape 73a is formed with respect to the dustproof collar 73 has been described as an example. About the convex-shaped and concave-shaped formation member formed in cooperation, it can change suitably.

  Furthermore, in the above-described embodiment, the form in which the outer side (rear side) of the rear bearing 18 installed in the large through hole 61b of the bearing support portion 61 of the motor case 12 is held by the tail cover 14 is exemplified. However, the member that holds the outer side (back side) of the rear bearing 18 may have any form as long as it functions as a cover member.

  It is apparent from the description of the scope of claims that embodiments with such changes or improvements can be included in the technical scope of the present invention.

  10 hand-held power tool, 11 housing, 12 motor case, 12a uneven shape, 13 gear case, 14 tail cover, 17 front bearing, 18 rear bearing, 19 cooling fan, 21 grinding wheel, 22 safety cover, 23 small bevel gear, 24 large bevel gear, 25, 26 bearing, 27 drive shaft, 28 on / off switch, 29 bearing rubber, 31 motor, 32 motor shaft, 32a front end, 32b rear end, 33 commutator, 61 bearing support, 61a Small through hole, 61b Large through hole, 71 dustproof labyrinth, 72 convex shape, 73 dustproof collar, 73a concave shape.

Claims (2)

A casing that houses the motor inside;
A rotary tool that rotates and receives a rotational driving force from the motor;
An outer peripheral portion of the motor storage portion in the casing is a handheld electric tool configured as a grip portion that receives grip from an operator,
The casing includes a bearing support portion for installing a bearing for supporting a motor shaft of the motor,
The bearing support is
A small through hole formed with a diameter smaller than the bearing outer diameter on the inner side where the motor shaft is inserted,
A large through hole formed open from the small through hole to the outer side of the casing with a diameter larger than the bearing outer diameter;
And is configured to insert the bearing from the outer side of the casing, and
A dust-proof labyrinth is formed on the inner side of the bearing support portion. The hand-held power tool according to claim 1,
The dust-proof labyrinth formation range is configured to be within an area of a bearing outer diameter or less.

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