JP2000092757A - Supporting structure of field - Google Patents

Abstract

PROBLEM TO BE SOLVED: To support a field accurately regardless of the deformation of a housing. SOLUTION: Four grooves 7, 7,... are formed on the outer circumferential surface of the field 5 extending over overall length in the axial direction, while four ribs 8, 8,... capable of being fitted in response to each groove 7 of the field 5 are projected in the same length as the grooves 7 in the axial direction. The grooves 7, 7,... and the ribs 8, 8,... are arranged at intervals of 90 deg. in a radial shape passing through the axial center of a motor housing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a field support structure for coaxially fixing a field of a motor used for a power tool or the like in a housing.

[0002]

2. Description of the Related Art FIG. 6 shows a conventional support structure. Reference numeral 10 denotes a motor housing, 11 denotes a field, 12 denotes an amateur, and a field 11 is provided on an inner surface of the motor housing 10.
Are projectingly provided on the outer surface of the motor housing 10. The ribs 13 support the field 11 in the motor housing 10 and support the armature 12 with the motor housing 10. The heart is matched.

[0003]

By the way, when the motor housing 10 is made of a water-absorbing material such as polyamide resin (nylon), the power tool is used in such a case that the housing comes into contact with water or is used in high humidity areas. In such cases, the size of the motor housing 10 may increase due to water absorption. Therefore, even when the motor housing 10 is assembled with its axes aligned at the time of absolute drying (water absorption rate 0%), as shown in FIG.
A gap is generated between the field 11 and each of the ribs 13 with the expansion of the motor, and the field 11 rattles to cause a misalignment with the motor housing 10 to generate noise and vibration, and to reduce the performance of the motor. Or decrease. Furthermore, this also causes the armature 12 and the field 11 held by the motor housing 10 to be misaligned, which causes the armature 12 and the field 11 to rub.

Therefore, the first aspect of the present invention is to provide a field support structure capable of accurately supporting a field without causing a misalignment of the field irrespective of a change in housing dimensions due to such water absorption. It is intended.

[0005]

In order to achieve the above object, according to the present invention, a rib is provided on one of an inner peripheral surface of the housing and an outer peripheral surface of the field, and the other is provided with a rib. A groove in which the rib can be fitted is formed in a recess, and the field can be fixed by fitting the rib with the groove. According to the second aspect of the present invention, in addition to the object of the first aspect, the rib and the groove can be easily formed, and the rib is provided on the inner peripheral surface of the housing in order to perform more reliable support. , Grooves are respectively formed on the outer peripheral surface of the field, and the ribs and the grooves are radially arranged in the cross-sectional direction of the housing.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory view of a grinder to which the support structure of the present invention is applied. The grinder 1 is rotated by a motor 3 incorporated in a cylindrical motor housing 2 made of nylon via a rotation transmission mechanism (not shown). A rotating grindstone 4 is provided. The motor 3 is a motor housing 2
A field 5 (shown in a simplified manner without distinguishing between iron cores and windings) and an armature 6 having both ends supported by ball bearings (not shown) in the motor housing 2 with the field 5 loosely inserted therein. Consists of Field 5
Are formed on the outer peripheral surface of the motor housing 2 at an interval of 90 ° radially from the axis and over the entire length in the axial direction, as shown in FIG. As shown in FIG. 3, four radial ribs 8, 8,... That can be fitted to the respective grooves 7 of the field 5 project in the axial direction with the same length as the grooves 7. When the field 5 is supported when the motor housing 2 is absolutely dry, the ribs 8 are
Are formed so as to fit in the circumferential direction (the width direction of the groove 7) without any gap.

In the grinder 1 configured as described above, when the field 5 is inserted into the motor housing 2 as shown in FIG. Since the movement is restricted in the circumferential direction by the engagement between the other pair of grooves 7, 7 and the ribs 8, 8, the field 5 has four radial grooves 7, 7,... And the ribs 8, 8,. Are firmly supported without rattling. Even if the motor housing 2 expands due to water absorption, as shown in FIG. 5, each rib 8 moves only radially in each groove 7 as the motor housing 2 expands, and does not deform in the circumferential direction. Therefore, the movement restricting action of each groove 7 and rib 8 does not change. Therefore, there is no misalignment with the motor housing 2 and the field 5 can always be supported accurately, and a favorable operation of the motor 3 can be ensured. Of course, friction between the field 5 and the amateur 6 does not occur.

The radial straight lines on which the ribs are arranged need not necessarily pass through the axis of the motor housing 2, but it is desirable to arrange at least two or more. If the number is not two or more, the movement is not regulated in all directions, and there is a possibility that rattling may occur in the fitting direction of any of the ribs and the groove.
Further, the angle between the ribs is set to 90 ° in the above embodiment, but it is also effective to set the angle within a range of ± 30 °, for example, to arrange three ribs every 120 °. Further, in the above embodiment, the groove 5 is provided in the field 5 and the motor housing 2 is provided.
Each of the ribs 8 is formed. In this case, there is obtained an advantage that it can be easily formed for each component, but the movement regulating action is not changed, so that they may be reversed. Others
The shape of the motor housing is not limited to the cylindrical integral shape, but can be similarly adopted in a form in which a half housing is combined.

On the other hand, in the above embodiment, the field is supported only by the four radial ribs and grooves.
If this structure is provided with protrusions and ribs (reference numeral 9 indicated by a two-dot chain line in FIG. 4) which are in contact with the surface of the field and is used in combination with the conventional structure, it is more effective in preventing misalignment.
In this case, depending on the arrangement and the number of the projections 9, the number of grooves and ribs fitted to each other can be reduced to reduce the processing portion on the field side, which is also preferable in terms of cost.

[0010]

According to the first aspect of the present invention, the field can be fixed by fitting the rib and the groove.
The field is firmly supported by the grooves and the ribs without rattling. Even if the housing expands due to water absorption, the ribs do not deform in the thickness direction, so that the movement restricting action between the ribs and the groove does not change. Therefore, there is no misalignment between the field and the housing, the field can be always supported accurately, and good operation of the motor can be ensured. Of course, there is no friction between the field and the amateur. According to the second aspect of the invention, in addition to the effect of the first aspect,
The rib is formed on the inner peripheral surface of the housing and the groove is formed on the outer peripheral surface of the field, and the rib and the groove are radially arranged in the cross-sectional direction of the housing, so that the rib and the groove are easily formed. As a result, the reliability of preventing misalignment is further improved.

[Brief description of the drawings]

FIG. 1 is an overall explanatory view of a grinder.

FIG. 2 is an explanatory cross-sectional view of a field.

FIG. 3 is an explanatory cross-sectional view of a motor housing.

FIG. 4 is an explanatory cross-sectional view of a motor housing supporting a field.

5 is an explanatory cross-sectional view showing a deformed state of the motor housing of FIG. 4 due to water absorption.

FIG. 6 is an explanatory cross-sectional view showing a conventional field support structure.

FIG. 7 is an explanatory sectional view showing a deformed state of the motor housing of FIG. 6 due to water absorption.

[Explanation of symbols]

1. Grinder, 2. Motor housing, 3.
Motor, 5 ・ ・ Field, 6 ・ Amateur, 7 ・ ・
Grooves, 8 ribs, 9 projections.

Claims (2)

[Claims] 1. A field support structure for coaxially fixing a field of a motor in a housing, wherein a rib is provided on one of an inner peripheral surface of the housing and an outer peripheral surface of the field, and the other side is provided with the rib. A field support structure, wherein a groove in which a rib can be fitted is recessed, and the field can be fixed by fitting the rib with the groove. 2. The field according to claim 1, wherein the rib is formed on the inner peripheral surface of the housing, and the groove is formed on the outer peripheral surface of the field, and the rib and the groove are radially arranged in the cross-sectional direction of the housing. Support structure.