JP3790824B2 - Rotor and method for manufacturing the same - Google Patents

Description

  The present invention relates to a rotor and a method for manufacturing the same.

  Conventionally, as shown in FIGS. 7 and 8, there is a manufacturing method and structure of a rotor used in a motor. The process of FIG. 7 is shown in Japanese Patent Application Laid-Open No. 8-237914, and is formed so that the shaft insertion hole of the rotor core assembly and the outer diameter of the shaft have the same or slight tolerance, and a slight tightening allowance is provided. In this method, after the shaft is inserted into the rotor core assembly, spot welding joining with a laser beam is performed at the joint position between the shaft insertion hole of the rotor core assembly and the shaft. The structure of FIG. 8 is shown in Japanese Utility Model Laid-Open No. 59-145248. The rotor core assembly 2 is provided with an enlarged diameter portion 4b2 in which the inner diameter 4b is partially enlarged to create a gap with the shaft. The structure for press-fitting the shaft is shown.

In the method of JP-A-8-237914, the rotor configured in this way can be inserted without play with little damage to the surface of the shaft when the shaft is inserted into the insertion hole of the rotor core assembly. Due to tolerance variations, there is a tightening allowance that requires an appropriate insertion pressure.If the shaft is thin, the shaft may be deformed by pressure, or may be affected by errors such as cylindricity or straightness of the rotor shaft insertion hole. To do.
In addition, the shaft may be damaged, and the deformation of the shaft does not become zero. Therefore, it is necessary to process and maintain the insertion hole of the rotor core assembly and the outer diameter of the shaft with high accuracy. Further, the outer diameter of the rotor has die-cast burrs, and it is necessary to remove the burrs.

Also, in order to reduce the insertion pressure to zero so that there is no interference when inserting the shaft into the rotor core assembly, it is necessary to heat the rotor core assembly to increase the diameter of the insertion hole of the shaft. Increase and heating equipment is required.
In Japanese Utility Model Laid-Open No. 59-145248, there is a problem that the shaft is easily damaged at the corner inside the shaft insertion hole when the shaft is press-fitted, the pressure input is increased, and the shaft is easily deformed.

  The present invention has been made to solve such a problem. Therefore, when inserting the shaft into the shaft insertion hole of the rotor core assembly, no force is applied to the shaft and the shaft is not deformed. It does not require high processing accuracy for the insertion hole and the outer diameter of the shaft, increases the joint strength between the shaft and the rotor core assembly, and improves the processing conditions for the outer diameter of the rotor.

The present invention includes a step of forming a rotor core assembly by laminating a rotor core provided with a through hole larger than the outer diameter of the shaft, a step of inserting the shaft into the through hole of the rotor core assembly, and an end face of the rotor core assembly And fixing the shaft, and welding the entire circumference of the coked end surface and the shaft with a laser beam, and then irradiating the coked end surface again with the laser beam after changing the welding conditions. And a step of welding the shaft and the rotor core assembly.

As described above, in the first aspect of the present invention, the end face of the rotor is caulked to fix the shaft, then the coked end face and the shaft are temporarily welded with a laser beam, and then the welding conditions are changed again. All-around welding is performed to irradiate the coked end surface with a laser beam, and the shaft and the rotor core assembly are welded. Therefore, the melted portion due to laser irradiation does not flow into the gap between the rotor and the shaft, and the weld bead The shape is stable and the welded portion is stable and of good quality, and high welding strength can be obtained without modifying the shaft.

Embodiment 1 FIG.
A first embodiment of the present invention will be described with reference to FIGS. In the figure, a rotor 1 is a rotor core assembly 2 in which a shaft 3 is fixed at a predetermined position. The rotor core assembly 2 is composed of a rotor core 4 and a conductor 5, and a plurality of rotor cores 4 are laminated into a cylindrical shape. It has a diameter 4a and an inner diameter 4b into which the shaft 3 is inserted concentrically with the outer diameter. There are two types of inner diameters 4b, an inner diameter 4b1 and an enlarged diameter portion 4b2 having a larger diameter than the inner diameter 4b1, and the rotor core 4 has two types of inner diameters 4b1 and 4b2. There are two types of inner diameter 4b in the present embodiment, but there may be three or more types depending on the shape of the shaft. The rotor core 4 has a slot 4c into which the conductor 5 enters near the outer diameter 4a. The slots 4c are provided at equal intervals with a pitch circle diameter that is partially open to the outer diameter 4a and concentric with the outer diameter 4a and the inner diameter 4b1 or 4b2.

  When the rotor core 4 is laminated on the rotor core assembly 2, the slots 4 c are slightly formed one by one in the circumferential direction of the outer diameter 4 a to form a skew for one pitch of the slot. The inner diameter 4b of the rotor core assembly 2 has a diameter-enlarged portion 4b2 that is enlarged by about 0.15 to 3 mm in diameter from the end surface 4d at a position where the thickness of the end surface 4d becomes a predetermined thickness. In addition, the thickness of the end face 4d is configured for each number of rotor cores 4 so as to have a thickness sufficient to weld and hold the shaft 3. The outer diameter 4a of the rotor core 4 is provided with a machining allowance of about 0.4 mm in the subsequent process in order to obtain dimensional accuracy. The size is such that a gap of 01 to 0.1 mm can be maintained. The rotor 1 configured as described above is manufactured by the following process.

The manufacturing process of the rotor 1 is shown in FIG.
As a first step, the rotor core 4 is punched and laminated so as to have a thickness equivalent to one, and a skewer is applied. The rotor core 4 is punched and laminated as follows. Since the inner diameter 4b into which the shaft 3 enters has two types of an inner diameter 4b1 and an enlarged diameter portion 4b2, the die is controlled by inserting and removing the punch for the inner diameter 4b1 and the punch for the enlarged diameter portion 4b2 at the beginning. The necessary number of punches having the inner diameter of 4b1 are punched, then the required number of punches having the inner diameter of 4b2 are punched, and then the required number of punches having the inner diameter of 4b1 are punched and laminated while sequentially caulking to the thickness of one unit. Form.

  Next, as a second step, the rotor core 4 laminated in a die-cast mold is set, and aluminum is die-cast to form a conductor 5 to obtain the shape of the rotor core assembly 2.

  Next, as a third step, the rotor core assembly 2 is taken out from the die-casting mold and cleaned to remove burrs, deposits, etc. of the die-cast formed near the outer diameter 4a and the conductor 5, and then the inner diameter 4b1 of the rotor core assembly 2 The inner diameter is made uniform within a certain range while crushing the irregularities on the inner surface by applying a rotary roller to the top.

  Next, as a fourth step, the rotor core assembly 2 is set in a jig and the shaft 3 produced in a separate step is inserted into the inner diameter 4b of the rotor core assembly 2, and the end surface 3b of the shaft 3 and the end surface 4d of the rotor core assembly 2 are connected. The shaft 3 is positioned at a predetermined position according to the positional relationship. The positioning dimension varies depending on the type of rotor.

Next, as a fifth step, the rotor 1 is welded to the end surface 4d of the rotor core assembly 2 and the outer diameter 3a of the shaft 3 by a laser welding machine.
In laser welding, as shown in FIG. 4, a position of 0.4 to 0.5 mm from the outer diameter 3 a of the shaft near the inner diameter 4 b 1 of the end face 4 d of the rotor core assembly 2 is 10 to 45 degrees with respect to the axis of the shaft 3. A laser beam is applied at an incident angle of 4 to melt the rotor end face 4d and the outer diameter of the shaft.

  As a laser welding method, first, the end face 4d of the rotor core assembly 2 is positioned and fixed to a predetermined position with respect to the laser welding head. Next, in this state (the rotor 1 does not rotate), laser welding is performed from the laser welding head 8 for 0.5 to 1 second to perform temporary welding. The purpose of this is to rotate the rotor 1 during the next round welding and fix the rotor core assembly 2 and the shaft 3 so as not to idle. The position where the laser beam is irradiated is aimed at a position 0.2 to 0.5 mm away from the outer diameter of the shaft 3 of the end face 4d of the rotor core assembly 2.

  Next, the welding conditions are changed, the rotor 1 is rotated while irradiating the laser beam again, and the entire circumference is welded to form the welded portion 7. The weld 7 has a bead width in which the end face 4d of the rotor core assembly 2 is completely melted and a part of the outer diameter 3a of the shaft is melted, and the depth is 1.5 to 2.0 mm in the plate thickness direction of the rotor core 4. Is formed. The irradiation time of the laser light is performed until the rotor core assembly 2 is rotated once or more, and is performed until the final welded portion is re-welded so as to overlap the previously welded portion. In this way, by superimposing the beginning portion and the end portion of the welded portion, a welded portion with good quality can be obtained without leaving an insufficiently welded portion.

Further, when the laser beam incident angle is as small as possible, the laser beam is likely to enter the rotor end face 4d, so that deep welding can be obtained in the plate thickness direction, thereby increasing the welding strength.
Further, since the weld area is large by welding all around, it is possible to join with high welding strength.

Further, the welding portion can be made smaller by laser welding, and since the heat generation amount is small, there is little thermal influence on the shaft 3 and the rotor core assembly 2 and there is no deformation due to heat of the shaft 3 so ) No need to work.
There are two methods of laser welding: one method for each side as shown in the figure and the other method for performing both surfaces simultaneously. The choice is made according to work conditions, automation status, product size, and the like.

  Next, as a sixth step, the outer diameter 4a of the rotor 1 is processed on the basis of the shaft 3 after welding. This processing is performed to remove die-cast burrs from the outer diameter 4a of the rotor 1 and at the same time to produce concentricity and coaxiality accuracy of the outer diameter 4a of the rotor core assembly 2 with respect to the shaft 3. This is done by grinding or the like.

  Next, as a final process, the rotor 1 is completed by subjecting the surface of the processed rotor core assembly 2 to rust prevention.

  Next, the inner diameter 4b will be described. When the inner diameter 4b of the rotor core assembly 2 has the same diameter and is straight, when the shaft 3 is inserted when there is an error such as cylindricity or straightness in the inner diameter 4b due to slight deviation of the individual rotor cores 4 in the stacked state, It is deformed by the error, and the straightness is deteriorated to cause shake. In order to eliminate the influence of this error, the central portion of the inner diameter 4b of the rotor core assembly 2 is made a large diameter enlarged portion 4b2 so that a gap is formed between the outer diameter 3a of the shaft 3. As a result, the central portion of the rotor core assembly 2 does not touch the shaft 3, and the shaft 3 is supported at two points on both end surfaces 4 d of the rotor core assembly 2, so that deformation such as bending is not caused.

  Further, since the inner diameter 4b1 on the end face 4d side of the rotor core assembly 2 has a clearance of 5 to 50 microns in radius with respect to the outer diameter of the shaft 3, the outer diameter 3a is damaged when the shaft 3 is inserted. Since the gap is small and the runout of the outer diameter 3a of the shaft 3 with respect to the outer diameter 4a of the rotor is small and can be sufficiently processed by the machining allowance provided for the rotor outer diameter 4a, The outer diameter 4a of the rotor can be processed without performing the above.

Embodiment 2. FIG.
In the second embodiment, after the shaft 3 is inserted into the rotor core assembly 2, laser welding is performed after the end surface 4d of the rotor core assembly 2 is caulked so that the position of the shaft 3 is not displaced until laser welding is performed. This will be described with reference to FIGS. Note that, except for the caulking in the figure, it is the same as that of the first embodiment, so that the description is omitted.

In the figure, the caulking 6 is performed so that the center of the caulking groove v is positioned on the end surface 4d of the rotor core assembly 2 at a position 0.2 to 0.5 mm away from the shaft outer diameter 3a close to the inner diameter 4b1 as shown in FIG. . The shape of the groove of the caulking 6 is a v-groove, and a plurality of holes are machined circumferentially or at a constant length and interval. The depth of the groove of the caulking 6 is about ½ of the plate thickness of the rotor core 4.
The inner diameter 4b1 of the end surface 4d of the caulked rotor core 4 is pressed against the outer diameter 3a of the shaft 3 so as to be in close contact with each other and the shaft 3 is fixed.

As shown in FIG. 6, the caulking 6 is processed by a dedicated jig after inserting the shaft 3 and before the laser welding process.
In the next step, laser welding is performed at a position of 0.4 to 0.5 mm from the outer diameter 3a of the shaft 6 of the coking 6 processed on the end face 4d of the rotor core assembly 2 from 10 degrees to 45 degrees with respect to the axis of the shaft 3. The end face 4d of the rotor core assembly 2 and the outer diameter 3a of the shaft are welded by applying a laser beam at an incident angle of.

  In the welded welded portion 7, the outer diameter 3a of the shaft 3 and the inner diameter 4b1 of the rotor core assembly 2 are in close contact with each other in the previous caulking, so that the melted portion flows into the gap between the inner diameter 4b1 and the outer diameter 3a of the shaft. Therefore, the weld bead shape does not collapse and the welded portion is stable and of good quality.

Sectional drawing of the rotor of Embodiment 1 of this invention. Sectional drawing of the rotor core assembly of Embodiment 1 of this invention. The manufacturing process figure of Embodiment 1 of this invention. The figure which shows the laser welding joining of this invention. The coking sectional drawing of the rotor of Embodiment 2 of this invention. The manufacturing process figure of Embodiment 2 of this invention. The flowchart which shows the manufacturing process of a prior art example. Sectional drawing of the rotor of a prior art example.

Explanation of symbols

  2 rotor core assembly, 3 shaft, 4b1 inner diameter, 4b2 expanded diameter part, 6 caulking.

Claims (4)

Forming a rotor core assembly by stacking rotor cores provided with through holes larger than the outer diameter of the shaft;
Inserting the shaft into the through hole of the rotor core assembly;
Caulking the end face of the rotor core assembly to fix the shaft;
The caulked end face and the shaft are temporarily welded with a laser beam, and then the welding conditions are changed, and then the entire circumference welding is performed by irradiating the caulked end face with the laser beam, and the shaft and the rotor core assembly are welded. And a process of
A method for manufacturing a rotor, comprising: The rotor manufacturing method according to claim 1, wherein the irradiation position of the laser beam for the temporary welding is set to a position that is 0.2 to 0.5 mm away from the outer diameter of the shaft. 3. The method for manufacturing a rotor according to claim 1, wherein the all-around welding is performed until the final welded portion overlaps and re-welds the previously welded portion. The rotor manufactured by the manufacturing method as described in any one of Claims 1-3.

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