JP2007152479A - Power tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve improvement in productivity and reduction of cost by simplifying assembling of a motor to a housing. <P>SOLUTION: In a grinder 1, a motor housing 2 storing a commutator motor 3 is constructed by a front housing 14 and a rear housing 15 which are divided forward and backward in the axial direction in an outer peripheral position of a stator 5, and the stator 5 is pressed only in the rear housing 15, and screwing is performed from the front housing 14 to the rear housing 15 with the stator 5 held between them, thereby assembling the stator 5 to the motor housing 2. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a power tool such as a grinder in which a motor as a driving source is accommodated in a cylindrical housing.

  In an electric tool such as a grinder, a motor is accommodated in a cylindrical motor housing (see, for example, Patent Document 1). The specific assembly of the motor to the motor housing is as follows. First, the motor stator (field) is press-fitted into the motor housing using a press-fitting jig (press), and then the stator is screwed to the motor housing. The procedure is to assemble the rotor.

JP 2001-9757 A

  By using the press-fitting jig as described above, it takes time and effort to assemble the product, which hinders productivity improvement and leads to an increase in cost.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an electric tool that simplifies the assembly of a motor to a housing and can be expected to improve productivity and reduce costs.

In order to achieve the above object, according to the first aspect of the present invention, the housing is divided into the front and rear in the axial direction at the outer peripheral position of the stator of the motor, and the stator is divided into only one of the front and rear divided housings. The stator is fixed by inserting and screwing to the one side divided housing with the stator sandwiched from the other side divided housing.
In addition to the object of the first aspect, the invention described in claim 2 provides an end on the split side of the split housing on either one of the front and rear sides so as not to impair the appearance and feeling of use even if the housing is split. In this portion, an extending portion is formed that is externally attached to an end portion of the opposite divided housing.
In addition to the object of the first or second aspect, at least one of the divided housings is also used as a handle in order to rationally use the divided housing.

According to the first aspect of the present invention, it is possible to assemble the motor without using a press-fitting jig, and it is possible to reduce labor and time for manufacturing work. In addition, since the mounting screws for the stator are also used for assembling the divided housing, the number of parts and labor for assembling will not increase even if the housing is divided, and the work can be simplified. Become. Therefore, productivity can be improved and manufacturing cost can be reduced.
According to the second aspect of the invention, in addition to the effect of the first aspect, the divided portion of the housing does not appear to the outside, and the appearance can be maintained. Further, the feeling of use is not impaired when the housing is gripped.
According to the third aspect of the invention, in addition to the effect of the first or second aspect, the divided housing can be rationally used as a handle.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a longitudinal sectional view of a grinder as an example of an electric tool, FIG. 2 is a plan view, and the grinder 1 is disposed in front of a motor housing 2 housing a commutator motor 3 (left side in FIG. 1). A gear housing 7 and a rear cover 8 are assembled to the rear via a bearing plate 6 that pivotally supports the third rotor 4. Here, the motor housing 2 and the rear cover 8 are made of synthetic resin, and the gear housing 7 is made of metal.
In the gear housing 7, a spindle 10 is pivotally supported orthogonally to the output shaft 9 of the rotor 4 protruding into the gear housing 7, and the first bevel gear 11 fixed to the tip of the output shaft 9 is connected to the spindle 10. The rotation of the output shaft 9 can be transmitted to the spindle 10 by meshing with the second bevel gear 12 fixed integrally. A disc-shaped grindstone 13 is mounted orthogonally on the lower end of the spindle 10 projecting downward from the gear housing 7.

  The motor housing 2 is divided into front and rear at an outer peripheral position near the rear of the stator 5, and a front housing 14 as a divided housing on one side that accommodates most of the stator 5 from the front, and a rear end portion of the stator 5. Is formed from the rear housing 15 as the other divided housing. The front housing 14 has a front end screwed to the gear housing 7 via the bearing plate 6 from the front, and a slide connected to a switch (not shown) housed in the rear cover 8 by a connecting bar 17 on its side surface. The button 16 is provided, and the ON / OFF control of the commutator motor 3 can be performed by sliding the slide button 16 while holding the front housing 14. Further, on the inner periphery of the front housing 14, seats 19, 19... For screws 18 for fixing the stator 5 are projected.

On the other hand, the rear housing 15 has a ring-shaped connecting portion 20 connected to the front housing 14 and a shaft support portion 21 that is connected to the rear center of the connecting portion 20 and supports the rear end of the rotor 4. The front end of the screw 18 inserted through the stator 5 from the front of the seat 19 of the front housing 14 can be screwed into the connecting portion 20. A pair of brush holders 23, 23 holding a carbon brush that is in sliding contact with the commutator 22 of the rotor 4 are provided on the rear surface of the connecting portion 20. Reference numeral 24 denotes a screw receiving portion that protrudes rearward from the shaft support portion 21 of the rear housing 15 and is used for screwing the rear cover 8.
At the rear end of the front housing 14, a step portion 25 that faces the front end of the connecting portion 20 of the rear housing 15, and an extending portion 26 that covers the front end outer peripheral portion of the connecting portion 20 and contacts the front end of the rear cover 8. Is installed around.

  In the grinder 1 configured as described above, when assembling the commutator motor 3 to the motor housing 2, first, the rear end of the stator 5 is lightly pushed into the connecting portion 20 of the rear housing 15 as much as possible by hand. To do. Next, the front housing 14 is sheathed in front of the stator 5, and a screw 18 is inserted through the stator 5 from the front of the seat 19 and screwed into the connecting portion 20. Then, as the screw 18 is screwed in, the stator 5 is completely press-fitted into the connecting portion 20 to be clamped and fixed between the receiving seat 19 and the connecting portion 20, and the front housing 14 and the rear housing 15 are integrated by the screw 18. It becomes. After that, the rotor 4, the gear housing 7, and the rear cover 8 may be assembled by a normal assembling procedure.

  Thus, according to the grinder 1 of the said form, the motor housing 2 is divided | segmented into the front and rear of the axial direction in the outer peripheral position of the stator 5, and the stator 5 is press-fitted only in the rear housing 15, and from the front housing 14 is carried out. By fixing the stator 5 by screwing the rear housing 15 with the stator 5 in between, the commutator motor 3 can be assembled without using a press-fitting jig. Can be shortened. In addition, since the screws 18 for attaching the stator 5 are also used for assembling the front and rear housings 14 and 15, even if the motor housing 2 is divided, the number of parts for assembly and labor are not increased. This simplification can be maintained. Therefore, productivity can be improved and manufacturing cost can be reduced.

In particular, the extended portion 26 that is externally mounted on the end of the rear housing 15 that faces the rear housing 15 is formed at the end of the front housing 14 so that the divided portion of the motor housing 2 does not appear to the outside. Can maintain good quality. Further, when the motor housing 2 is gripped, the feeling of use is not impaired.
Furthermore, since the front housing 14 of the motor housing 2 is also used as a handle, the front housing 14 can be used rationally, and the grinder 1 can be used with good operability.

The press-fitting side of the divided housing is not limited to the rear side as in the above embodiment, but may be press-fitted to the front side. However, if the setting is such that the press-fitting portion is reduced as in the above embodiment, assembly is easy. It becomes. However, if the load at the time of assembly is small due to the axial length of the stator or the like, it is possible to set the press-fitting portion to be large, for example, by dividing at the center of the stator. Therefore, the divided housing also serving as the handle may be the rear side or both.
Also, the screwing directions of the divided housings may be screwed from the rear side, and the structure of the receiving seat and the female screw portion used for screwing can be appropriately changed.
Furthermore, although the extending portion is provided in the front housing in the above embodiment, it can be provided in the rear housing. Of course, if there is no problem in appearance or feeling of use, the extended portion may be eliminated and simple end-to-end matching may be performed.

On the other hand, the housing to be divided is not limited to being made of synthetic resin, but may be made of metal. However, it can be said that a synthetic resin that easily causes a water absorption error is preferable as an object of the present invention.
Further, the effect of the present invention can be maintained even if the stator is simply inserted into the split housing on one side, depending on the material of the housing.
In addition, the power tool is not limited to a grinder, and the present invention can be applied to other types such as a sander as long as a motor (which is not limited to a commutator motor) is accommodated in a cylindrical housing. is there.

It is a longitudinal cross-sectional view of a grinder. It is a top view of a grinder.

Explanation of symbols

1 .... Grinder, 2 .... Motor housing, 3 .... Commutator motor, 4 .... Rotor, 5 .... Stator, 7 .... Gear housing, 8 .... Rear cover, 13 .... Disk-shaped grinding wheel, 14 .... · Front housing, 15 ·· Rear housing, 18 ·· Screw, 19 ·· Seat, 20 ·· Connection portion, 21 ·· Shaft support portion, 25 ·· Step portion, 26 ·· Extension portion.

Claims (3)

An electric tool in which a stator of a motor housed in a cylindrical housing is fixed by insertion into the housing and screwing into the housing,
The housing is divided into front and rear in the axial direction at the outer peripheral position of the stator, the stator is inserted only into one of the front and rear divided housings, and the stator is sandwiched from the other divided housing. An electric tool characterized in that the stator is fixed by screwing to a split housing on one side.   The power tool according to claim 1, wherein an extending portion that is externally attached to an end portion of the opposite divided housing is formed at an end portion on the divided side of the divided housing on either one of the front and rear sides. The power tool according to claim 1 or 2, wherein at least one of the divided housings is also used as a handle.

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