JP2007223006A - Portable tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact, low-priced and long service life portable tool, since work efficiency becomes bad, if a large load applied to a cover and screws for fixing a bearing during a grinding or polishing work is treated by increasing the size of each part. <P>SOLUTION: The portable tool has: an electric motor 1; a case 6 for storing the electric motor 1; a driving gear 2a transmitted with driving force of the electric motor 1; a driven gear 2b engaged with the driving gear 2a, a driving shaft 3 mounted with the driven gear 2b; a distal end tool 9 mounted on the driving shaft 3; and fixtures 5a and 5b for fixing the distal end tool 9. A thrust bearing 7 is provided between the fixtures 5a and 5b and the case 6. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a portable tool. In the following, a disk grinder used for grinding and polishing a work material will be described as an example.

  FIG. 2 is a cross-sectional view of an essential part showing a conventional disc grinder. As shown in FIG. 2, the conventional disc grinder has a built-in electric motor 1, and when a worker inputs a switch (not shown), the driving force generated from the electric motor 1 is engaged with the driving gear 2a and the driving gear 2a. It is transmitted to the drive shaft 3 via a driven gear 2 b attached to the shaft 3. A disk-shaped grindstone 9 as a tip tool is fixed to the drive shaft 3 by fixtures 5a and 5b, and the work material is ground and polished by rotating the grindstone 9.

JP 2002-321173 A

  Grinding and polishing operations using the disc grinder are performed in a state where the grindstone is pressed against the work material. Therefore, a large load is applied during grinding and polishing operations to the drive shaft, the bearing that holds the drive shaft via the fixture that fixes the grindstone, and the cover and the screw that fix the bearing. This problem has been addressed by increasing the size of each component. However, since the size of the main body is increased, there is a drawback that workability is deteriorated.

  In addition, dust generated by grinding and polishing often enters the internal mechanism through a gap between the main body case and the drive shaft. For this reason, the internal mechanism part such as a bearing is abnormal. This problem was addressed by using an expensive bearing equipped with a dust mechanism. However, there is a problem that the price of the disc grinder becomes expensive.

  An object of the present invention is to provide a portable tool that eliminates the above-mentioned conventional drawbacks and is compact, low-cost, and has a long life.

  In order to achieve the above object, the invention of claim 1 includes an electric motor, a case for housing the electric motor, a driving gear to which the driving force of the electric motor is transmitted, a driven gear meshing with the driving gear, and the driven gear. In a portable tool having a drive shaft to which a drive gear is attached, a tip tool attached to the drive shaft, and a fixture for fixing the tip tool, a thrust bearing is provided between the fixture and the case. It is characterized by.

  The invention according to claim 2 is characterized in that a labyrinth structure is formed by the fixture and the case.

  According to the first aspect of the present invention, it is possible to reduce the burden on the internal mechanism portion and extend the life by dispersing the reaction force from the work material generated during the grinding and polishing operations. Moreover, since the size of the internal mechanism portion can be reduced, a compact portable tool can be provided.

  According to the second aspect of the present invention, it is possible to prevent the dust from entering the internal mechanism and extend the life of the bearing. In addition, since an inexpensive bearing that does not have a dustproof structure can be employed, an inexpensive portable tool can be provided.

  FIG. 1 is a cross-sectional view of an essential part showing a disc grinder according to an embodiment of the present invention. In FIG. 1, when an operator inputs a switch (not shown), the power generated from the electric motor 1 is driven via a driven gear 2 a attached to the drive shaft 3 via the drive gear 2 a, the drive gear 2 a, or the drive gear 3. 3 is transmitted. A disc-shaped grindstone 9 as a tip tool is fixed to the drive shaft 3 between the fixture 5a and the fixture 5b by an axial force generated by screw fitting between the fixture 5b and the drive shaft 3, and the grindstone 9 rotates. By doing so, the work material 10 is ground and polished. Further, the fixture 5 a is fitted with a two-surface width 4 provided on the drive shaft 3. A thrust bearing 7 is disposed between the fixture 5a and the main body case 6 that houses the electric motor 1, the drive gear 2a, and the driven gear 2b, and the outer circumferential position is limited by the cylindrical outer wall 8. The outer wall 8 forms a labyrinth structure with a groove 11 provided in an annular shape in the main body case 6. Further, a gap 15 is provided in the axial direction of the fixture 5 a and the drive shaft 3, and axial force due to screw fitting is applied to the main body case 6 via the thrust bearing 7.

  A thrust bearing 7 is provided between the fixture 5 a and the body case 6, and a gap 15 is provided in the axial direction of the fixture 5 a and the drive shaft 3. Therefore, as in the prior art, the reaction force 12 from the work material generated during the grinding and polishing operations is not transmitted only to the drive shaft 3, and the reaction force 12 can be dispersed. In other words, the component force 13 a transmitted to the main body case 6 via the fixture 5 a and the thrust bearing 7 and the component force 13 b transmitted to the bearing 14 via the fixture 5 b and the drive shaft 3 are dispersed. Therefore, the burden on the internal mechanism can be reduced and the life can be extended. Further, unlike the prior art, it is not necessary to increase the size of the internal mechanism so as to withstand a large load. Therefore, a compact portable tool can be provided.

  By forming the labyrinth structure with the fixture 5a and the main body case 6, it is possible to prevent the dust generated by grinding and polishing from entering the internal mechanism. Therefore, the life of the internal mechanism such as the bearing 14 can be extended. Moreover, since the inexpensive bearing 14 which does not take a dust-proof structure can be employ | adopted, an inexpensive portable tool can be provided.

  Further, the embodiment of the present invention is not limited to the disc grinder, and can be applied to portable tools such as a drill and a polisher.

1 is a cross-sectional view of an essential part showing an embodiment of a disc grinder according to the present invention. Sectional drawing which shows the principal part which shows one Embodiment of the conventional disc grinder.

Explanation of symbols

1 is an electric motor, 2a is a driving gear, 2b is a driven gear, 3 is a driving shaft, 4 is a width of two surfaces, 5a and 5b are fixtures, 6 is a body case, 7 is a thrust bearing, 8 is an outer wall, and 9 is a tip tool. , 10 is a work material, 11 is a groove, 12 is a reaction force, 13a and 13b are component forces, 14 is a bearing, and 15 is a gap.

Claims (2)

An electric motor,
A case for housing the electric motor;
A driving gear to which the driving force of the electric motor is transmitted;
A driven gear meshing with the driving gear;
A drive shaft to which the driven gear is attached;
A tip tool attached to the drive shaft;
In a portable tool having a fixture for fixing the tip tool,
A portable tool comprising a thrust bearing between the fixture and the case. The portable tool according to claim 1, wherein a labyrinth structure is formed by the fixture and the case.

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