JP2008278597A - Rotor core - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a rotor core which is easy to fasten a motor shaft even if the processing accuracy of individual thin plates is relatively low, thereby easily suppressing its manufacture cost. <P>SOLUTION: When constituting a rotor core 20 by stacking two or more thin plates 10 which have motor shaft insertion holes 1, each of the two or more thin plates has a cylindrical main part 3, where the motor shaft insertion hole larger in diameter than the motor shaft is made at the center, and two or more elastically transformable sections 5 which are connected with the inwall of the motor shaft insertion hole. Besides, each of the two or more elastically transformable sections has an arcuate body whose tip gets in as far as a region occupied by the motor shaft, projecting into the motor shaft insertion hole while forming an arc shape from the connection point with the inwall of the motor shaft insertion hole. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a rotor core used in a motor, and more particularly to a rotor core of a type in which a plurality of thin plates are laminated.

  As one of the rotor cores used in motors, there is a type of rotor core in which a predetermined number of disk-shaped thin plates made of electromagnetic steel plates or the like are stacked and these thin plates are fixed by caulking or laser welding. Each thin plate has a motor shaft insertion hole formed in advance, and the motor shaft is shrink-fitted or press-fitted into the rotor core after the rotor core is manufactured. When the predetermined number of thin plates are stacked so that the distance between the rotor core and the stator is within an allowable range when the motor is assembled, positioning is performed based on the outer diameter of each thin plate.

  The above type of rotor core is suitable for improving the energy efficiency of the motor and reducing the size of the motor. However, in order to achieve a sufficient fastening force of the motor shaft by the rotor core, each thin plate is Since positioning is performed based on the outer diameter of the thin plate, it is necessary to increase the processing accuracy such as the position accuracy and shape accuracy of the motor shaft insertion hole in each thin plate, and the manufacturing cost increases. If the position accuracy and shape accuracy of the motor shaft insertion hole in each thin plate is low, the fastening force of the motor shaft by the rotor core will be insufficient and slipping of the motor shaft will occur, so that sufficient torque transmission force can be obtained It becomes difficult. Alternatively, it is difficult to shrink fit or press fit the motor shaft into the rotor core.

  A rotor core used in the rotor structure described in Patent Document 1 is known as a rotor core capable of obtaining a sufficient torque transmission force without increasing the machining accuracy of the motor shaft insertion hole in each thin plate. Yes. In this rotor core, a plurality of teeth are arranged on the hole wall of the motor shaft insertion hole (center hole) in each thin plate so that the hole wall has an uneven shape, and on the circumference centered on the central axis of the rotor core. The tip of the tooth is located. The motor shaft is press-fitted into the rotor core. At this time, the above-mentioned teeth formed on the individual thin plates are plastically deformed to absorb an error in processing accuracy.

JP-A-4-285446

  However, in the rotor core described in Patent Document 1, the tips of the teeth formed on the hole walls of the individual thin plates must be positioned on the circumference centered on the central axis of the rotor core. Fabrication is performed under high processing accuracy, or inner diameter processing is performed to correct the end face of the tooth after lamination of the thin plates. In addition, since a large number of teeth are formed in the motor shaft insertion hole when viewed from the whole rotor core, the load necessary to press-fit the motor shaft, in other words, the load necessary to plastically deform each tooth. Is also relatively large.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to obtain a rotor core in which a motor shaft can be easily fastened and manufacturing costs can be easily suppressed even if the processing accuracy of individual thin plates is relatively low.

  The rotor core of the present invention that achieves the above object is a rotor core in which a plurality of thin plates each having a motor shaft insertion hole are laminated, and each of the plurality of thin plates has a motor shaft insertion hole larger in diameter than the motor shaft. A disc-shaped main portion formed in the central portion and a plurality of elastic deformation portions connected to the inner wall of the motor shaft insertion hole, each of the plurality of elastic deformation portions being a motor shaft insertion hole; It is an arc-shaped body that protrudes into the motor shaft insertion hole while drawing an arc from the connection portion with the inner wall, and the tip portion enters into a region occupied by the motor shaft.

  In the rotor core of the present invention, the above-described elastic deformation portion provided on each thin plate is elastically deformed when the motor shaft is inserted and is pressed against the outer peripheral surface of the motor shaft, thereby fastening the motor shaft. The motor shaft can be easily fastened even if the processing accuracy of each thin plate is relatively low compared to the case where the motor shaft is fastened using the plastic deformation of teeth formed on each thin plate as in the rotor core described in 1. can do. When press-fitting the motor shaft into the rotor core, the load required for press-fitting the motor shaft can be made relatively small. It is not always necessary to perform inner diameter processing after laminating each thin plate. For these reasons, it is easy to reduce the manufacturing cost of the rotor core. Therefore, according to the present invention, it is possible to obtain a rotor core that allows easy fastening of the motor shaft at low cost.

  Hereinafter, embodiments of a rotor core of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the embodiments described below.

  1 is a front view schematically showing an example of a rotor core, FIG. 2 is a perspective view schematically showing a thin plate constituting the rotor core shown in FIG. 1, and FIG. It is a top view which shows the shown rotor core roughly.

  A rotor core 20 shown in FIG. 1 is obtained by laminating a plurality of disk-like thin plates 10 made of electromagnetic steel plates or the like, and then crimping and fixing them. Each thin plate 10 is positioned and laminated on the basis of its outer diameter. As shown in FIG. 2, each thin plate 10 includes a disc-shaped main portion 3 having a motor shaft insertion hole 1 having a diameter larger than that of a motor shaft (not shown) at the center portion, and a motor shaft insertion hole. A plurality of elastic deformation portions 5 connected to one inner wall, and a connection portion 7 projecting from the inner wall of the motor shaft insertion hole 1 into the motor shaft insertion hole 1 to connect the elastic deformation portion 5 and the main portion 3. Have.

  In each thin plate 10 shown in FIG. 2, a total of four elastic deformation portions 5 are formed at equal intervals along the inner wall of the motor shaft insertion hole 1. Further, one connection portion 7 is formed corresponding to one elastic deformation portion 5 and is connected to the central portion in the longitudinal direction of the elastic deformation portion 5. Each of the elastically deforming portions 5 is an arc-shaped body, and the inside of the motor shaft insertion hole 1 is drawn while drawing an arc from a connection location with the inner wall of the motor shaft insertion hole 1, in other words, a connection location with the connection portion 7. Protruding. Each elastic deformation portion 5 is curved with a curvature larger than the curvature of the outer peripheral surface of the motor shaft, and the tip portion of each elastic deformation portion 5 is in a region occupied by the motor shaft in the motor shaft insertion hole 1. It has entered. Further, the center of curvature of each elastic deformation portion 5 is in the motor shaft insertion hole 1, and the distance between the elastic deformation portion 5 and the center of the motor shaft insertion hole 1 is directed from the above-mentioned connection portion to the above-mentioned tip portion. It becomes shorter gradually according to.

  As shown in FIG. 3, the azimuth angle of the elastic deformation portion 5 is shifted by 45 degrees between the thin plates 10 and 10 adjacent to each other in the stacking direction. Each thin plate 10 has an azimuth angle of the elastic deformation portion 5 of 45 degrees in a fixed direction from the azimuth angle of the lower thin plate 10 when the azimuth angle of each elastic deformation portion 5 in the lowermost thin plate is used as a reference. Laminated and stacked. When the thin plates 10 are laminated in this manner, even if each thin plate 10 is made of one material, it is easy to obtain a rotor core 20 having a substantially uniform thickness by offsetting thickness unevenness in the material. Note that reference numeral 15 in FIG. 3 indicates a caulking portion for fixing each thin plate 10.

  In the rotor core 20 having the above-described configuration, as shown schematically in FIG. 4, when the motor shaft 30 is inserted into the motor shaft insertion hole 1, each elastic deformation portion 5 is elastically deformed, and the tip portion thereof is a motor. Press contact with the outer peripheral surface of the shaft 30. In FIG. 4, only one thin plate 10 is drawn for convenience, and the thin plate 10 is smudged.

  The motor shaft 30 may be shrink-fitted into the rotor core 20 or may be press-fitted. When the motor shaft 30 is press-fitted into the motor shaft insertion hole 1, each elastic deformation portion 5 is elastically deformed as described above. Therefore, for example, the plasticity of teeth formed on each thin plate like the rotor core described in Patent Document 1 The load required for press-fitting the motor shaft 30 can be made relatively small even if the processing accuracy of the individual thin plates 10 is relatively low, compared to the case where the motor shaft is fastened using deformation. The motor shaft 30 can be easily fastened by the rotor core 20. At this time, it is not always necessary to perform the inner diameter processing after laminating the thin plates 10. Each thin plate 10 can be easily formed by, for example, pressing (punching). For these reasons, in the rotor core 20 described above, it is easy to reduce the manufacturing cost.

  In addition, the shape of the elastic deformation part in each thin plate which comprises the rotor core of this invention is not limited to the shape shown in FIG. 2, It can change variously. For example, the curvature of each elastic deformation portion can be set to the same value as the curvature of the outer peripheral surface of the motor shaft or the same value over the whole or at the tip.

  FIG. 5 is a plan view schematically showing another example of a thin plate constituting the rotor core. A thin plate 40 shown in the figure is connected to a disk-shaped main portion 33 in which a motor shaft insertion hole 31 having a diameter larger than that of a motor shaft (not shown) is formed at the center, and an inner wall of the motor shaft insertion hole 1. And a plurality of connecting portions 37 that project from the inner wall of the motor shaft insertion hole 31 into the motor shaft insertion hole 31 and connect the elastic deformation portion 35 and the main portion 33. Yes. One connection portion 37 is formed in one elastic deformation portion 35.

  Each elastically deforming portion 35 is an arc-like body, similarly to the elastically deforming portion 5 shown in FIG. Projecting into the motor shaft insertion hole 31 while drawing. The region other than the tip 35a of each elastic deformation portion 35 is curved with a curvature larger than the curvature of the outer peripheral surface of the motor shaft, and the tip 35a is bent with the same curvature as the curvature of the outer peripheral surface of the motor shaft. Yes. Further, the distal end portion of each elastically deforming portion 5 enters the area occupied by the motor shaft in the motor shaft insertion hole 1. The center of curvature of each elastic deformation portion 35 is in the motor shaft insertion hole 31, and the distance between these elastic deformation portions 35 and the center of the motor shaft insertion hole 31 gradually increases from the above-mentioned connection portion toward the above-mentioned tip portion. It is getting shorter.

  In the thin plate 40 configured as described above, as schematically shown in FIG. 6, when the motor shaft 30 is inserted into the motor shaft insertion hole 31, each elastic deformation portion 35 is elastically deformed, and the tip portion 35a thereof. Is in pressure contact with the outer peripheral surface of the motor shaft 30. Since each tip portion 35a is curved with the same curvature as that of the outer peripheral surface of the motor shaft 30, these tip portions 35a and the outer peripheral surface of the motor shaft 30 are in surface contact. As a result, as compared with the thin plate 10 shown in FIG. 2, the contact area between each elastic deformation portion 35 and the motor shaft 30 increases and the fastening force with respect to the motor shaft 30 increases.

  Therefore, if the rotor core is configured by laminating a predetermined number of thin plates 40, the motor shaft 30 can be easily fastened even if the processing accuracy of the individual thin plates 40 is relatively low, as in the rotor core 20 shown in FIG. As compared with the rotor core 20 shown in FIG. 1, a motor shaft 30 having a stronger fastening force can be easily obtained at low cost.

  FIG. 7 is a plan view schematically showing still another example of a thin plate constituting the rotor core. A thin plate 50 shown in the figure is connected to a disk-shaped main portion 43 in which a motor shaft insertion hole 41 having a diameter larger than that of a motor shaft (not shown) is formed at the center, and an inner wall of the motor shaft insertion hole 41. And a plurality of connecting portions 47 that project from the inner wall of the motor shaft insertion hole 41 into the motor shaft insertion hole 41 and connect the elastic deformation portion 45 and the main portion 43. Yes. One connection portion 47 is formed in one elastic deformation portion 45.

  Each elastically deforming portion 45 is an arc-like body like the elastically deforming portion 5 shown in FIG. 2, and an arc is formed from a connecting portion with the inner wall of the motor shaft insertion hole 41, in other words, a connecting portion with the connecting portion 47. It projects into the motor shaft insertion hole 41 while drawing. Each elastic deformation portion 45 is curved with a curvature larger than the curvature of the outer peripheral surface of the motor shaft, and the distal end portion of each elastic deformation portion 45 is in a region occupied by the motor shaft in the motor shaft insertion hole 41. It has entered. Further, the center of curvature of each elastic deformation portion 45 is in the motor shaft insertion hole 41, and the distance between the elastic deformation portion 45 and the center of the motor shaft insertion hole 41 is directed from the connection point to the tip portion. It becomes shorter gradually according to. Each connection portion 47 is connected to one end of the corresponding elastic deformation portion 45.

  In the thin plate 50 configured as described above, as in the thin plate 40 shown in FIG. 5, when the motor shaft is inserted into the motor shaft insertion hole 41, each elastic deformation portion 45 is elastically deformed, and the connection portion The end opposite to the end to which 47 is connected is pressed against the outer peripheral surface of the motor shaft. As a result, if the rotor core is configured by laminating a predetermined number of thin plates 50, the same technical effect as the rotor core 20 shown in FIG. 1 can be obtained. 2 shows an example in which a connecting portion between the elastic deformation portion and the inner wall of the motor shaft insertion hole is provided at the longitudinal center of the elastic deformation portion, and FIG. 7 shows an elastic deformation portion at one end in the longitudinal direction of the elastic deformation portion. Although an example in which a connection portion between the motor shaft insertion hole and the inner wall of the motor shaft insertion hole is shown, the connection portion between the elastic deformation portion and the inner wall of the motor shaft insertion hole can be appropriately selected depending on the material, plate thickness, and the like. .

  In addition, the number of the elastic deformation parts in each thin plate which comprises the rotor core of this invention can be made into two or more desired numbers. When n elastic deformation portions (n is an integer of 2 or more) are formed on each thin plate at equal intervals, the azimuth angle of each elastic deformation portion is shifted by (180 / n) degrees between the thin plates adjacent in the stacking direction. Is preferred. When the thin plates are laminated in this manner, even if each thin plate is made of one material having uneven thickness, it becomes easy to obtain a rotor core having a substantially uniform thickness. In addition to the arcuate body having the center of curvature in the motor shaft insertion hole as described above, each elastic deformation portion may be an arcuate body having the center of curvature outside the motor shaft insertion hole. It is also possible to omit the connecting portion and connect the elastically deforming portion directly to the inner wall of the motor shaft insertion hole. The electromagnetic shield structure of the present invention can be variously modified, modified, combined, etc. other than those described above.

It is a front view showing roughly an example of the rotor core of the present invention. It is a perspective view which shows roughly the thin plate which comprises the rotor core shown in FIG. FIG. 2 is a plan view schematically showing the rotor core shown in FIG. 1. It is a top view which shows roughly the state of each elastic deformation part when a motor shaft is inserted in the motor shaft insertion hole of the rotor core shown in FIG. It is a top view which shows roughly the other example of the thin plate which comprises the rotor core of this invention. FIG. 6 is a plan view schematically showing a state of each elastic deformation portion when the motor shaft is inserted into the motor shaft insertion hole of the thin plate shown in FIG. 5. It is a top view which shows roughly still another example of the thin plate which comprises the rotor core of this invention.

Explanation of symbols

1, 31, 41 Motor shaft insertion hole 5, 35, 45 Elastic deformation portion 10, 40, 50 Thin plate 20 Rotor core 30 Motor shaft 35a Tip of elastic deformation portion

Claims (8)

A rotor core in which a plurality of thin plates having motor shaft insertion holes are laminated,
Each of the plurality of thin plates includes a disk-shaped main portion in which a motor shaft insertion hole having a diameter larger than that of the motor shaft is formed at a central portion, and a plurality of elastic members connected to the inner wall of the motor shaft insertion hole. A deformation portion,
Each of the plurality of elastically deforming portions protrudes into the motor shaft insertion hole while drawing an arc from a connection point with the inner wall of the motor shaft insertion hole, and a tip portion extends to a region occupied by the motor shaft. An arcuate body,
A rotor core characterized by that.   2. The rotor core according to claim 1, wherein each of the plurality of elastic deformation portions is an arc-shaped body having a center of curvature in the motor shaft insertion hole.   3. The rotor core according to claim 1, wherein a connection portion between the elastic deformation portion and the inner wall of the motor shaft insertion hole is a central portion in a longitudinal direction of the elastic deformation portion.   3. The rotor core according to claim 1, wherein a connection portion between the elastic deformation portion and the inner wall of the motor shaft insertion hole is one end in a longitudinal direction of the elastic deformation portion.   5. The apparatus according to claim 1, further comprising a connection portion that protrudes from an inner wall of the motor shaft insertion hole into the motor shaft insertion hole and connects the main portion and the elastic deformation portion. The described rotor core.   6. The rotor core according to claim 1, wherein each of the plurality of elastic deformation portions is curved with a curvature larger than a curvature of an outer peripheral surface of the motor shaft.   The rotor core according to any one of claims 1 to 5, wherein a tip portion of each of the plurality of elastically deformable portions is curved with the same curvature as the curvature of the outer peripheral surface of the motor shaft.   Each of the plurality of elastic deformation portions has n (n is an integer of 2 or more) elastic deformation portions formed at equal intervals, and in the thin plates adjacent in the stacking direction, the plurality of elastic deformation portions The rotor core according to any one of claims 1 to 7, wherein each azimuth is shifted by (180 / n) degrees.

Images