JPH0417559A - Motor structure - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides a motor in which at least one end surface of a side plate surrounding a stator is closed with an end plate, and these end plates and the side plate are assembled by welding. When using resistance welding, which applies high voltage while pressurizing the side plate and end plate, due to dimensional variations, the end plate comes into contact with the stator, resulting in an electrical short circuit, resulting in insufficient welding current. The present invention relates to a motor structure that can prevent welding defects.

BACKGROUND OF THE INVENTION Many types of conventional motor assembly structures are known, depending on the application and classification of the motor. As an example of these many motor structures, FIG. 4 shows the structure of a stepping motor. Conventionally, when assembling this motor 10,
The outer peripheral surface of the cylindrical stator 12 is surrounded by a side plate 14 having a C-shaped cross section, and both axial end faces of the side plate 14 are closed with circular end plates 16, and the portions indicated by arrows A are exposed to plasma. The side plate 14 and end plate 16 were fixed by welding. Note that a rotor 18 is housed in the hollow portion 12a of the stator 12, and a rotating shaft 20 of the rotor 18 is rotatably supported by bearings 22 provided on each of the end plates 16.

Further, in the figure, the reference numeral 28 indicates a lead wire connection portion to the motor winding in the stator 12.

However, the plasma welding described above has disadvantages such as a complicated welding process and an increased installation cost of a welding machine.

Therefore, from the viewpoint of simplifying the welding process and reducing welding costs, it has been proposed to employ resistance welding as shown in FIGS. 2 and 3. For example, small protrusions 14a are formed at required intervals on the upper and lower edges of the C-shaped side plate 14, respectively.
, and when assembling the motor, these small protrusions 14a
The side plate 14 and the end plate 16 are brought into contact via (see FIG. 2). Then, the side plate 14 and the end plate 1 are connected via the small protrusion 14a.
6, both end plates 16.16 sandwiching the side plate 14 are pressurized in the axial direction by the upper electrode 24 and the lower electrode 26, thereby causing the small protrusion 14a to 27.
Crush it about 3 times.

Next, by applying a required voltage to the picture electrodes 24, 26 and flowing a large current between the end plate 16 and the small protrusions 14a, the small protrusions 14a are melted.
Each end plate 16 and side plate 14 are welded at the locations indicated by .

'a1 problem that the invention seeks to solve The aforementioned resistance welding is compared to plasma welding.

Although the introduction has sufficient advantages in terms of simplifying the welding process and reducing welding costs, on the other hand, the following drawbacks have been pointed out. That is, the protrusion dimension of the small protrusion 14a formed for resistance welding is extremely small, and the distance between the upper and lower open end surfaces of the stator 12 surrounded by the side plate 14 and each end plate 16 varies slightly. is intervening. For this reason, during welding work, the image electrode 24, 26
is activated and pressurizes both end plates 16.16 that sandwich the side plate 14 to crush the small protrusion 14a, each end surface of the stator 12 may come into contact with the corresponding end plate 16.

In this state, when voltage is applied to the picture electrodes 24 and 26, the welding current is applied to the stator 1 which is in contact with the tJX protrusion 14a and the end plate 16, which are the original welding points.
2 and the end plate 16, resulting in a so-called electrical short circuit. In this case, the value of the welding current will be lower than the value required for welding, and therefore the strength at the welded location will be significantly reduced, resulting in product defects.

Furthermore, during resistance welding, fine powder of metals, oxides, etc. is inevitably scattered around due to instantaneous melting of the welded portion. At this time, since the hollow part 12a of the stator 12 and each end plate 16 are spatially connected as shown in FIG.
It will invade the inside of the body and adhere to various parts. This may disrupt the delicate magnetic balance between the rotor 18 and stator 12,
There is a problem in that the fine gap between the rotor 18 and the stator 12 is bridged, which greatly hinders the smooth operation of the motor 10.

Purpose of the Invention The present invention has been proposed to suitably solve the above-mentioned problems, and the present invention solves the problem of dimensional variations when assembling the side plates surrounding the stator and at least one end plate by resistance welding. It is an object of the present invention to provide a motor structure that effectively prevents an end plate from contacting a stator and causes an electrical short circuit, secures the supply of necessary welding current, and performs good resistance welding.

Means for Solving the Problems In order to overcome the above-mentioned problems and achieve the intended purpose, the present invention provides a structure in which a rotor is rotatably housed, the outer peripheral surface of the stator is surrounded by a side plate, and the side plate In a motor structure configured such that at least one end face in the axial direction of the motor is closed with an end plate and welded.

A spacer having a required thickness and provided with a bearing for supporting the rotor is interposed between each corresponding stator and the end plate to be welded, so that a spacer is provided between the stator and the end plate. The structure is characterized in that it is configured to ensure the required air gap.

According to the present invention, since a spacer having a required thickness is interposed between the stator and the end plate, even if the end plate is pressurized by the upper and lower electrodes during resistance welding, there is no space between them. The required air gap is always ensured, so that the electrical insulation between the stator and the end plate is maintained and a shunt of the welding current is prevented.

Embodiment Next, a preferred embodiment of the motor structure according to the present invention will be described below with reference to FIG. In the illustrated embodiment, the upper opening of the hollow portion 12a of the stator 12 is provided with a bearing 32 that supports the rotating shaft 20. It is fixedly closed by a spacer 34.

The spacer 34 is made of plastic resin and has a required thickness, and this thickness is such that when the upper end plate 16 is placed against the side plate 12 for motor assembly, the spacer 34 contacts the upper end surface of the stator 12. It is interposed between the end plate 16 and the space between them (12
, 16) are set to dimensions that ensure the required gap G.

In this case, the spacer 34 is, as can be seen from FIG.
It is preferable to integrally mold the stator 12 with a resin coating of a required thickness along the inner periphery of the hollow portion 12a using a resin injection molding machine.

Further, the lower opening of the stator 12 is closed by a spacer 36 formed separately from the spacer 34. This spacer 36 is also provided with a bearing 32 that supports the rotating shaft 20, and when the lower end plate 16 is placed against the side plate 12,
It is interposed between the lower end surface of the stator 12 and the end plate 16, and is dimensioned to ensure a required space between them.

Note that the side plate 14 has the same markings as described in connection with FIG.
Small protrusions 14a are provided at required intervals on the upper and lower edges.
are formed, and when assembling the motor, these small protrusions 14a
The side plate 14 and the end plate 16 are brought into contact with each other via.

Effects of the Embodiment Next, the effects of the motor structure according to this embodiment will be explained. When assembling the motor 10, as described with reference to FIG. 2, the side plate 14 and the end plate 16 are brought into contact via the small projections 14a, and both end plates 16.16 sandwiching the side plate 14 are connected to the upper and lower electrodes 24°26 Pressure is applied in the axial direction to crush the small protrusion 14a. At this time, in the embodiment, a spacer 3 is provided between the upper end surface of the stator 12 and the end plate 16.
4 is interposed to secure a required gap G between them, and another spacer 36 is also interposed between the lower end surface of the stator 12 and the end plate 16 to similarly secure a gap G between them. are doing. Therefore, electrical insulation is maintained between the stator 12 and the end plate 16 even when pressurized by both electrodes 24, 26.

Therefore, even if the required voltage is applied to both electrodes 24 and 26,
Since no electrical short circuit occurs between the stator 12 and the end plate 16, and the required welding current value is obtained at the resistance welding part, each end plate 16 and the side plate 14 are welded well. .

Therefore, the structural strength of the motor 10 is stably maintained over a long period of time. Furthermore, since the spacers 34 and 36 seal the upper and lower openings in the hollow part 12a of the stator 12, even if fine powder such as metal or oxide is inevitably scattered during resistance welding, this will not be absorbed into the hollow part 12a. 12a is effectively prevented, and the performance of the motor after assembly is not adversely affected.

In the above example, the case where the end plates on both sides are welded together is shown, but it is also possible to weld only one end plate and attach the other end plate by another fixing method or to form it integrally with the side plate. You can do it like this.

As described in detail, according to the motor structure of the present invention, when the side plate surrounding the stator and at least one end plate are fixed by resistance welding, there is a gap between the end plate and the stator. A spacer of a required thickness is interposed to ensure a required gap between the two at all times. Therefore, even if pressure is applied to the side plate in the axial direction of the end plate for resistance welding, the end plate and the stator will not come into contact and cause an electrical short circuit, and the necessary welding current value for the welded part can be obtained. Therefore, good welding that always satisfies the specified strength can be achieved.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional view showing a preferred embodiment of the motor structure according to the present invention, FIG. 2 is a schematic explanatory diagram of welding the upper and lower end plates and side plates of a stepping motor by resistance welding, and FIG. This figure is a longitudinal sectional view showing the stepping motor shown in FIG. 2 in a state where resistance welding has been completed, and FIG. 4 is an outside view showing the assembled structure of the stepping motor. 0...Motor 12...Stator 2a...Hollow part 14...Side plate 4a...Small protrusion 16...End plate 8...Rotor 20...Rotating shaft 2... bearing
24, 26... Electrode 8... Lead wire connection part 0... Welding part 32... Bearing 4. 36... Spacer

Claims (2)

[Claims] (1) In a motor structure in which a rotor is rotatably housed, the outer peripheral surface of the stator is surrounded by a side plate, and at least one axial end face of the side plate is closed and welded with the end plate, A spacer having a required thickness and provided with a bearing for supporting the rotor is interposed between each corresponding stator and the end plate to be welded, so that a spacer is provided between the stator and the end plate. A motor structure characterized in that it is configured such that a required air gap can be secured between the two. (2) The motor structure according to claim 1, wherein the spacer is configured to hermetically close a rotor storage portion formed in the stator.