JPH0442894B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fixing structure for a bracket of a molded motor.

There are two possible ways to fix the bracket of the molded motor, depending on the direction of the force applied to the bracket.

Figure 1 shows an example of this.Stator core 1
A stator 4 is formed by winding a winding 2 around and integrally molding and fixing it with a mold resin 3. On the other hand, the rotor 5 is fixed to the rotating shaft 6, and the bearings 7a, 7b that support the rotating shaft 6 are attached after the brackets 8a, 8b are press-fitted into the pilot parts 4a, 4b provided on the stator 4, and the bearings 7a, 7b are attached to the rotary shaft 6. Retaining rings 9a and 9b are attached to the shaft 6 from both outsides of 7a and 7b.

When assembled in this way, suppose a force F ₁ is applied to the shaft 6 from the right side, and the force F ₁ is transmitted to the bearing 7a via the retaining ring 9a, then to the bracket 8a, and finally to the stator. The end face of the spigot part of No. 4 is pushed with a force of F ₁ '. In the case of force in the opposite direction, the same procedure can be followed. This method is often used in pulley motors, conveyor rollers, etc. because the pullout load is not applied to the bearing or bracket on the opposite side to the direction in which the force is applied.

However, with this method, the brackets 8a and 8b
Since the bearings 7a, 7b are installed after the rotor 5 is installed, it becomes impossible to assemble the bearings 7a, 7b integrally with the rotor 5 in advance.

Therefore, multiple assembly operations are required. Also, the inner shaft and outer bracket must be loosely aligned around the bearing, which may cause slippage between these three during rotation, resulting in creep of the bracket or shaft. As a result, the product could not be used as a general electric motor due to its reliability.

FIG. 2 shows another example. The stator 4 is formed similarly to the previous example. On the other hand, the rotor 5 is assembled in advance by attaching retaining rings 9a, 9b to its shaft 6, and furthermore, bearings 7a, 7b are attached and fixed to the outside of the retaining rings 9a, 9b. Then, it is held on the spigot parts 4a, 4b of the stator by brackets 8a, 8b,
The bolts 11a and 11b are tightened and fixed to the nuts 10a and 10b embedded during stator molding.

This method is generally adopted, and the basic difference from the previous example is that the force _F1 applied to the shaft 6 is transmitted in a direction that tries to separate the bracket on the opposite side from the side to which the force is applied. be.

Therefore, a fixing force sufficient to withstand this is required for fixing the brackets 8a, 8b and the stator 4.

On the other hand, compared to the previous example, the shaft 6 and the bearings 7a and 7b can be integrated by press-fitting, so there is no concern about reliability such as creep in the bearing part, and partial assembly can be used. It can be done much more rationally.

However, with this configuration, it is necessary to embed the nuts 10a and 10b, which takes time and effort during molding, and
In order to ensure the pull-out strength after embedding the nuts 10a, 10b, the nuts 10a, 10b must be embedded to a certain degree of thickness, and the molding thickness must be increased accordingly. Furthermore, winding 2 and nut 10
It is also necessary to provide a sufficient insulation distance between a and 10b. On the other hand, the heads of the bolts 11a, 11b for tightening and fixing the brackets 8a, 8b protrude on both sides of the motor end face, making it difficult to install the motor.

Another example of the second method is to fix the bracket only by pressing force into the spigot part of the stator, or by using adhesive in combination, but this is because the dimensions of the spigot part are limited by thermal expansion. This is a method that is difficult to adopt because there is a risk that the interference will become smaller and the pull-out load will decrease when the tension changes.

The present invention is the second bracket mounting structure.
It belongs to the system of 1999, and attempts to make use of its strengths while correcting its shortcomings.

The present invention will be described in detail below using an example in which the present invention is applied to a toroidal winding motor in which a yoke is wound in each slot of a stator core.

FIG. 3 is a partially cutaway side view of an embodiment of the present invention, and FIG. 4 is a sectional view taken along line X-X' in FIG.

In the figure, a stator core 1 has toroidal windings 2 wound around the yoke portions of each slot.

The rotor 5 is assembled in advance by attaching the retaining rings 9a, 9b to the shaft 6, and then attaching and fixing the bearings 7a, 7b to the outside thereof. And brackets 8a, 8
b is held in the spigot parts 4a, 4b of the stator 4 by the screws 4a and 4b of the stator 4.

At this time, a hole 12 is provided that penetrates from one end surface of the stator 4 to the other end surface, and on the other hand, the hole 12 of the mounted brackets 8a and 8b is
The same number of holes of the same size are also provided in the parts corresponding to the brackets 8a and 8a, respectively.
8b and the stator 4 are fixed together.

If the winding 2 is loose, the loose wire 14 may be exposed to the inner surface of the through hole during molding, as shown by the thick broken line in FIG.

This kind of thing often occurs during molding due to the influence of resin flow, etc.

When this happens, the rivet 13 and through hole 12
Since there is no large dimensional difference between the rivet 13 and the loose wire 14, an insufficient electrical insulation distance occurs between the rivet 13 and the loose wire 14.

Here, as shown in FIG. 5, the outer periphery of the rivet 13 is covered with a plastic film tube 15 having electrical insulation properties. Alternatively, a plastic film adhesive tape 16 may be wrapped around it as shown in FIG.

Furthermore, as shown in FIG. 7, a heat-shrinkable plastic film tube 17 may be covered and heat-shrinked. As described above, an electrical insulating layer is formed around the rivet 13, and the rivet is inserted into the through hole 12 for use.

As a result, the problem of insufficient insulation distance can be solved, and a molded motor with excellent quality and reliability can be obtained.

In the embodiment, a rivet with a circular cross section was used as the fixing means, but it goes without saying that the effect will not change at all even if the fixing means is a rivet with a non-circular cross section or a through bolt is used as the fixing means.

As is clear from the above description, the present invention provides the following effects.

(1) No space is required for insert nuts or bolts, and the distance between the core end face and stator end face can be made smaller than in the conventional method, resulting in a thinner motor.

(2) Even if the windings become loose, there will be no insulation failure, greatly improving reliability.

(3) Unlike the conventional method using inserts, the strength of fixing the bracket is not affected by the molding conditions, and the strength of the rivet becomes the fixing strength, resulting in stable quality.

(4) Since the protrusion of bolts or nuts from the stator end face is eliminated or reduced, the mounting thickness of the motor becomes even thinner.

(5) In the case of inserts, the diameter of the pitch circle is relatively large, so the outer diameter of the bracket must also be larger than that. However, in the case of the present invention, the pitch circle is near the slot opening, so the outer diameter of the bracket can be made smaller, material costs can be reduced, and the weight of the motor can be reduced.

etc., it has a great effect on obtaining products that are more compact and of better quality than conventional molded motors.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a molded motor showing a conventional bracket mounting structure, FIG. 2 is a cross-sectional view of a molded motor showing another conventional bracket mounting structure, and FIG. 3 is a molded motor according to an embodiment of the present invention. FIG. 4 is a cross-sectional view taken along the line X-X' in FIG. 3; FIG. 5 is a perspective view showing a state in which the outer periphery of the rivet is covered with a plastic film tube; FIG. 6 is a partially cutaway side view of the motor; 7 is a perspective view showing a state in which a plastic film adhesive tape is wrapped around the outer periphery of a rivet, and FIG. 7 is a perspective view showing a state in which a heat-shrinkable plastic film tube is placed around the outer periphery of the rivet and heat-shrinked. DESCRIPTION OF SYMBOLS 1...Stator core, 2...Winding, 3...Mold resin, 4...Stator, 4a, 4b...Pilot part, 5...Rotor, 6...Shaft, 7a, 7b...Bearing , 8a, 8b... bracket, 9a, 9b...
Retaining ring, 12... hole, 13... rivet (fastener), 15... plastic film tube,
16... Adhesive tape, 17... Heat-shrinkable plastic film tube.

Claims (1)

[Scope of Claims] 1. A stator in which an annular stator core having slots and a winding housed in the slots are integrally molded with resin, a rotor disposed within the stator, and the rotor. In a molded motor consisting of a bearing that rotatably supports the stator, and a bracket that holds the bearing integrally with the stator, the stator has one hole for each slot that passes through the slot of the iron core. At least two or more are provided on the same pitch circle, and the same number of holes are also provided in the brackets at positions corresponding to the holes, and the stator and the brackets disposed on both sides are connected to the outer periphery passing through the holes. A molded motor that is integrally fixed with metal fasteners that have an electrically insulating layer. 2. The molded motor according to claim 1, wherein the electrical insulating layer provided on the fastener is formed by covering it with a plastic film tube. 3. The molded motor according to claim 2, wherein the electrical insulating layer provided on the fastener is formed by covering it with a heat-shrinkable plastic film tube. 4. The molded motor according to claim 1, wherein the electrical insulating layer provided on the fastener is formed by wrapping an adhesive tape. 5. The molded motor according to claim 1, wherein the windings are wound in a toroidal manner around the yoke portion of each slot.