JPH0519384B2 - - Google Patents

Description

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

Conventional Structure and Problems There are two methods for fixing the bracket of the molded motor, which can be broadly classified based 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 supporting 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. Retaining rings 9a and 9b are attached to the shaft 6 from both outer sides of the bearings 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 bearings 7a and 7b are installed after the brackets 8a and 8b are installed.
It becomes impossible to assemble a and 7b integrally with the rotor 5 in advance. Therefore, the assembly work becomes complicated. Also, there must be play between the inner shaft and the outer bracket with the bearing as the center.
Slippage occurs between these three during rotation, resulting in creep of the bracket or shaft.
Due to the reliability of the product, it could not be used as a general electric motor.

FIG. 2 shows another example. The stator 4 is formed similarly to the previous example. On the other hand, the stator 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 thereof. 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 shaft 1 is transmitted in a direction that attempts to separate the bracket from the stator on the side opposite to the side where the force is applied. It is a point.

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.
Also, partial assembly can be used for assembly, making it much more efficient.

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 with a certain thickness, and the molding thickness l 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 method 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.

Furthermore, as another example of the second method, there is a structure shown in FIG. The stator 4 is formed similarly to the previous example. On the other hand, the rotor 5 is also assembled in the same manner as the example shown in FIG. 2, and is held in the spigot parts 4a, 4b of the stator by brackets 8a, 8b.

Here, in order to prevent the brackets 8a, 8b from coming off or coming off, retaining ring grooves 12a, 12b are provided by cutting or the like in the portions of the pilot parts 4a, 4b corresponding to the outside of the brackets 8a, 8b. The retaining rings 13a and 13b are inserted into these grooves using their spring force.

In this structure, the bracket 8a,
This is to prevent 8b from coming off, and usually at least 2~
3mm is required, and the width of the retaining ring grooves 12a and 12b
t _S (usually 1.5 to 2 mm) and bracket plate thickness t _B (usually 1
~1.5mm), the distance L from the stator end face to the bracket contact surface due to the mold is t + t _S
+t _B , usually (2-3) + (1.5-2) + (1-1.5) =
4.5-6.5mm is required. This ratio was a major obstacle when designing a thin molded motor with a small axial length. Also, retaining ring groove 12
Since insertion is not possible unless there is a slight gap between the width _tS of a and 12b and the thickness of the retaining rings 13a and 13b, create a gap by making _tS slightly larger than the thickness of the retaining rings 13a and 13b. However, after assembly, due to this gap, it is unavoidable that the brackets 8a and 8b vibrate in the axial direction, and in order to prevent this, the retaining ring 13
Corrugated washers 14a, 14b are inserted between a, 13b and brackets 8a, 8b. Therefore, the retaining rings 13a, 13b must be inserted and mounted while pushing the corrugated washers 14a, 14b, making it extremely difficult.

Furthermore, since the brackets 8a and 8b are rotatable within the stator spigots, they rotate at a very low speed together with the rotor 5 due to vibrations, etc., and it is expected that an accident will occur in which the resin spigot parts are scraped.

On the other hand, when looking at the radial dimension for machining the retaining ring grooves 12a and 12b, the distance l ₁ (normally
1.5mm) and provide a spigot part, and it is necessary to further carve the required depth l ₂ (usually 1.5mm) from the spigot part for the retaining ring grooves 12a and 12b.
It is necessary to ensure a resin wall thickness of at least 3 mm from the inner diameter surface of the stator. Therefore, it is not possible to place electrical components such as stator windings and outlet connections in this 3mm area, and in order to secure this 3mm area, the inner diameter of the coil end must be shaped in advance before molding. Although it is possible to widen it, it is difficult to secure this 3 mm portion with a small motor. For this reason, the axial position of the retaining ring grooves 12a, 12b is adjusted to the coil end (usually 20 to 20 degrees from the end surface of the stator core 1).
25mm), which was a constraint in making the motor thinner.

OBJECTS OF THE INVENTION The present invention belongs to the second type of bracket mounting structure, and aims to take advantage of its advantages while correcting its disadvantages.

Structure of the Invention The present invention provides an opening in the axial direction of the stator end surface and the inner diameter surface in a molded portion between the core end surface and the stator end surface on the inner diameter surface of a stator in which a stator core and a winding are integrally molded with resin. a plurality of cutout portions having a width of 1.5 mm, a groove including a bottom surface in the axial direction of these cutout portions and having a width in the direction of the end face of the stator, and a protrusion provided at an outer peripheral portion position corresponding to the cutout portion of the stator. bracket and
A ring-shaped presser spring having a plurality of protrusions on the inner circumference for pressing the bracket against the stator and a ring-shaped presser spring having a protrusion on the outer circumference corresponding to the notch of the stator is attached to the groove of the stator. It is integrally fixed.

DESCRIPTION OF EMBODIMENTS 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. 4 is a side view of the embodiment of the present invention, and FIG.
The figure is a sectional view taken along the line A-O-B in FIG. 4.
Fig. 6 is a perspective view of the bracket and ring-shaped presser spring (hereinafter simply referred to as presser spring) attached to the stator, Fig. 7 is a perspective view of an example of the presser spring, and Fig. 8 is a perspective view of the bracket. FIG.

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

The rotor 5 is disposed inside the stator 4 with a bearing 7 mounted on its shaft 6, and is rotatably held by the stator 4 from both sides by brackets 8.

Here, in the spigot part of the inner diameter surface of the stator 4,
A plurality of notches 4d are provided in the axial direction along the inner diameter surface. A groove 4c is formed by cutting or the like so as to include the axial bottom surface of the notch 4d and have a width as described later in the direction of the end surface of the stator 4. The depth of the groove 4c is approximately the same as the radial depth of the notch 4d (usually
1.5mm). The cutout portion 4d can be provided by simultaneous molding during molding. On the other hand, bracket 8
The outer circumferential surface 8c is a fitting part with the spigot part, and the same number of protrusions 8d are provided at the same positions and in the same number as the notches 4d on the inner diameter surface of the stator, which are slightly smaller than the dimensions of the notches 4d and have a size that is easy to insert. The projection 8d projects in the axial direction from the outer peripheral surface 8c, and its end surface is brought into contact with the core side wall surface 4c' of the groove 4c. Furthermore, the presser spring 12 is provided with the same number of protrusions 12d on the outer periphery of the ring-shaped disc 12a at the same positions as the notches 4d, similar to the bracket, and a plurality of protrusions 12e on the inner periphery for pressing the bracket. . By adopting such a structure of the presser spring 12, as shown in FIG.
It has a spring structure that presses the core side wall surface 4c' of the groove 4c. These are assembled by attaching the bracket 8 to the stator 4.
, and further insert the presser spring 12. While pushing the protrusion 12d of the presser spring 12 in the axial direction, rotate it to the right or left as shown by the arrow in FIG. protrusion 12 of
d into the groove. The axial cross section of the notch 4d immediately before rotation after inserting the bracket 8 and the presser spring 12 is as shown in FIG.

With the above configuration, the following effects can be obtained compared to the conventional example.

(1) In the case of the conventional example shown in Fig. 3, the brackets 8a, 8
b into the spigot part of the stator 4, then insert the corrugated washers 14a and 14b, and then tighten the retaining ring 1.
3a, 13b (normally a C-shaped retaining ring is used) must be inserted into the grooves 12a, 12b while pushing the corrugated washer, whereas according to the present invention, the protrusion of the presser spring 12 12e, insert the protrusion 8d of the bracket 8 into the groove 4.
Since it is pressed against the iron core side wall surface 4c' of c, the conventional corrugated washer is not necessary, and the number of parts can be reduced. The assembly method is as follows: insert the bracket 8 and the presser spring 12 into the notch 4d of the stator, and then rotate the protrusion 12d of the presser spring 12 while pushing it in the axial direction, and insert it into the groove. It is extremely simple to automate assembly and streamline the process.

(2) Compared to the adhesive method, the bracket 8 can be disassembled.

(3) No insert parts are required during molding,
The molding process can be streamlined.

(4) Since no insert parts are required, a product that is thinner and has improved insulation and other reliability can be obtained.

(5) From the first method above, bearings, brackets,
There is no need to worry about creep occurring between the shafts, resulting in improved quality.

(6) Compared to the method shown in Figure 3 where a retaining ring groove is provided and the retaining ring is used to secure the retaining ring, the method shown in Figure 3 has t _S + t _B = 2.5.
However, since the present invention does not require a corrugated washer, the plate thickness of the presser spring 12 (usually 0.3 to 0.5 mm) and the plate thickness of the bracket 8 (1
~1.5mm) and the gap between the protrusion 12d of the presser spring and the protrusion 8d of the bracket and the groove 4c (usually
0.3 to 0.5 mm), t _S ′ + t _B ′ = 1.6 to 2.5
mm. Therefore, even if the distance t from the side wall surface of the stator end surface of the groove 4c to the stator end surface is 2 to 3 mm, which is the same as in the case of FIG. 3, the L dimension is 3.6 to 5.5 mm.
It can be made smaller by about 1 mm than the conventional example, and the axial thickness of the motor can be reduced by about 2 mm on both sides.

(7) In the case of a system using a retaining ring, the depth of the retaining ring groove from the inner diameter surface of the stator must be 3 mm, but in the case of the method according to the present invention, the depth of the notch and groove corresponding to the retaining ring groove is 3 mm. Only 1.5mm is sufficient. With this size, the inner diameter of the coil end can be shaped in advance before molding to allow internal parts such as windings to escape. Therefore, according to the present invention, the axial position of the groove can be provided at a portion lower than the coil end height, and the thickness from the stator core end face to the stator end face can be made 10 mm to 15 mm thinner than before. Therefore, a thinner motor can be obtained.

(8) As in the first example, there is no change in the fixing strength of the bracket due to expansion and contraction of the pilot part, and stable fixation of the bracket can be achieved.

Effects of the Invention As described above, the present invention greatly improves the bracket fixing structure, which was a major drawback of conventional molded motors, by integrally rotating and inserting the bracket and the presser spring into the bracket mounting groove. It is something that can be done.

Although the present invention has been described as an embodiment in which the winding is a toroidal winding, the present invention is not limited to this, and it is of course applicable to any molded motor having a bracket, regardless of the winding method or shape. It is.

[Brief explanation of the drawing]

Figure 1 is a sectional view of a molded motor showing a conventional bracket mounting structure, Figures 2 and 3 are sectional views of a molded motor showing another conventional bracket mounting structure, and Figure 4 is an embodiment of the present invention. A side view of such a molded motor, FIG. 5, is A-O- in FIG.
6 is a perspective view of the bracket according to the present invention in an assembled state; FIG. 7 is a perspective view of an example of the presser spring according to the present invention; and FIG. 8 is a perspective view of an example of the bracket of the present invention. , FIG. 9 is an enlarged sectional view of the main part immediately before the bracket is fixed. DESCRIPTION OF SYMBOLS 1...Stator core, 2...Winding, 3...Mold resin, 4...Stator, 4c...Groove, 4d...Notch, 5...Rotor, 6...Shaft, 7... bearing, 8
... Bracket, 12 ... Presser spring, 12a ...
Ring-shaped disc, 12d...Protrusion, 12e...Protrusion.

Claims (1)

[Scope of Claims] 1. A stator in which a stator core and windings are integrally molded with resin, a rotor disposed within the stator, and a rotor rotatably supported via a bearing. A molded motor comprising a bracket and a ring-shaped presser spring that presses the bracket against the stator, wherein the stator has a molded portion between the stator core end face and the stator end face on the inner diameter surface of the stator. a plurality of notches having openings in the axial direction of the stator end surface and the inner diameter surface;
a groove that includes the bottom surface in the axial direction of the notch and has a width in the direction of the end face of the stator; the bracket is provided with a protrusion at an outer peripheral position corresponding to the notch of the stator; and the ring-shaped presser spring is provided with a protrusion at an outer circumferential position corresponding to the notch of the stator, and a plurality of protrusions are provided on the inner circumference of the protrusion for pressing the bracket toward the stator core, and the protrusion of the bracket and the 1. A method of manufacturing a molded motor, characterized in that the projecting portion of a ring-shaped presser spring is integrally pushed into a cutout portion of the stator mold portion, and rotationally inserted into the groove and fixed.