JPH0775279A - Resin-molded motor - Google Patents

Abstract

PURPOSE:To provide a resin molded type electric motor where the mounting strength of a bracket does not decrease and reliability is high even when an electric motor is run continuously for a long time for releasing heat. CONSTITUTION:A rotor 3 is inserted into the hollow part of a stator 1, its rotary shaft is supported by a bearing 4 which is retained at the bracket 5, the bracket 5 is press fitted and fixed into a hole 21 of the end face of a molding resin part 2 of the stator 1, and the bracket 5 is held and fixed by a fixing ring 6 with a large coefficient of thermal expansion and the inside of the hole 21 of the molding resin part 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing structure for a stator frame and a bracket of a resin mold type electric motor.

[0002]

2. Description of the Related Art In recent years, resin molding of electric motors has progressed rapidly, and resin molded electric motors have come to be used in most of electric motors used in home electric appliances.

Conventionally, in this type of resin mold type electric motor, various methods have been adopted for the fixing structure of the bracket in terms of accuracy, reliability, cost and workability.
In particular, with a focus on cost and workability, we are moving toward the direction of not using screws or rivets for fixing the bracket.

FIG. 4 shows an assembly of a bracket used in a conventional resin mold type electric motor. As shown in the figure, the rotor 9 is inserted into the hollow portion of the stator 7, and the bracket 11 is press-fitted and fixed inside the hole of the molded resin portion 8 of the stator 7. At this time, the bearing 10 is fitted and held in the recess of the bracket 11.

As described above, the bracket 11 is held only by being press-fitted inside the molding resin 8 without being fixed by screws or rivets.

[0006]

In such a conventional structure, since the bracket is fixed only by press fitting into the hole of the molded resin portion on the end face side of the stator, the electric motor generates heat by operating for a long time. In that case, there is a problem that the press-fit strength is significantly reduced due to the difference in thermal expansion coefficient between the mold resin and the bracket, and the bracket loosens or falls off.

The present invention solves the above problems, and an object thereof is to provide a highly reliable bracket fixing means in which the press-fitting strength of the bracket does not decrease even when the motor is continuously operated for a long time and generates heat. It is a thing.

[0008]

In order to achieve this object, a resin mold type electric motor according to the present invention comprises a bracket which is press-fitted inside a mold resin portion of a stator frame, a fixing ring having a coefficient of thermal expansion larger than that of the bracket, and a mold. It is sandwiched inside the resin part to fix the bracket.

[0009]

With this configuration, when the resin mold type motor generates heat due to continuous long-term operation or when it is installed in a cold region and the bracket expands due to the difference in thermal expansion between the resin, the fixing ring, and the metal, the inner diameters of the brackets are different from each other. When the resin mold expands and the resin mold expands, the fixing ring also expands to spread the bracket and secure the tightening margin between the bracket and the resin mold, and firmly and stably fix the resin mold and the bracket. Become.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a sectional view of a resin mold type electric motor showing the assembly of the bracket 5. As shown in the figure, the rotor 3 is inserted into the hollow portion of the stator 1, and its rotation axis is the bracket 5
It is supported by a bearing 4 held by. The bracket 5 for holding the bearing 4 is press-fitted and fixed inside the hole 21 in the end surface of the mold resin portion 2 of the stator 1, and the bracket 5 is further fixed to the fixing ring 6 and the hole 21 of the mold resin portion 2 having a large coefficient of thermal expansion. It is sandwiched and fixed by the inside of.

FIG. 2 shows the assembly of the bracket 5, the mold resin portion 2 of the stator 1 and the press-fitting portion of the fixing ring 6. The bracket 5 is sandwiched and fixed by the fixing ring 6 having a large coefficient of thermal expansion and the inside of the hole 21 of the mold resin portion 2.

FIG. 3 shows the assembled state of FIG. The fixing ring 6 is generally selected from a material having a higher coefficient of thermal expansion than the bracket 5, but by adjusting the press-fitting margin with the bracket 5, it is possible to securely fix the fixing ring 6 even if the coefficient of thermal expansion is almost the same. .

[0014]

As is apparent from the above description of the embodiments, according to the present invention, a bracket in which a mold resin portion is press-fitted and fixed is sandwiched between the inside of the mold resin portion and a fixing ring having a coefficient of thermal expansion larger than that of the bracket. The following effects can be obtained by immobilizing and fixing. (1) When fixing the bracket to the stator, there is no need to use screws or rivets, and the cost and workability can be greatly improved. (2) Even if the coefficient of thermal expansion of the molded resin part of the stator and the bracket are different, the fixing ring fixes the inner side of the resin part and the bracket in a press-fitted state, so the fixing strength of the bracket decreases even if the temperature changes. Without, reliability is greatly improved.

[Brief description of drawings]

FIG. 1 is a sectional view of a resin-molded electric motor showing an assembly of a bracket according to an embodiment of the present invention.

FIG. 2 is a partial sectional view showing an assembly of a bracket, a mold resin and a fixing ring according to an embodiment of the present invention.

FIG. 3 is a diagram showing an assembled state of an embodiment of the present invention.

FIG. 4 is a cross-sectional view showing assembly of a conventional bracket.

[Explanation of symbols] 1 Stator 2 Mold resin part 4 Bearing 5 Bracket 6 Fixing ring 21 Hole

Claims (1)

[Claims] 1. In a resin-molded electric motor in which a winding-finished product in which a winding is wound on an iron core is molded with a resin having an electric insulation property, a bracket is press-fitted inside a molded resin portion and the bracket serves as a fixing ring. A resin mold type electric motor characterized in that it is sandwiched and fixed inside the mold resin portion.