JP2022029750A - Manufacturing method of rotor shaft - Google Patents

Abstract

To provide a manufacturing method of a rotor shaft which improves fixing power in a fastening portion between members.SOLUTION: A manufacturing method of a rotor shaft includes: a processing step of forming a protrusion 11 extending from one end side in a width direction of a tabular member 1 to the other end side in the width direction and protruding in a plate thickness direction of the tabular member 1, and a cross-sectional shape in which at least two U-shaped parts each having a U-shaped cross section are connected in a cross section in a view in a length direction of the tabular member 1; an anchor part forming step of forming a recess 18 at one end side in the width direction of the tabular member 1 and forming a projection 17 which can be fitted so as to be caught in the recess 18, at the other end side in the width direction; an anchor bending step of deforming the projection 17 in a plate thickness direction of the projection 17; a bending processing step of pressing a portion where the cross sections of the at least two U-shaped parts are connected with each other, to form the tabular member 1 in a hollow shape; and an anchor fitting step of returning the deformation which is applied to the projection 17, to an original state and fitting the projection 17 into the recess 18.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for manufacturing a rotor shaft.

The rotor of a rotary electric machine is composed of a rotor shaft rotatably supported by the housing of the rotary electric machine and a rotor core (laminated steel plate) assembled with the rotor shaft. In assembling the rotor shaft and the rotor core, connecting the constituent members, etc., the portion where each member is fastened requires a fixing force that can withstand the rotation of the rotor.

In Patent Document 1, a rotor shaft having an outer shape having a non-circular cross section is formed, and a predetermined number of magnetic thin plates having a non-circular center hole corresponding to the outer shape of the non-circular cross section of the rotor shaft are stacked to form a rotor core. Is formed, the rotor shaft is inserted into the non-circular center hole of the rotor core, and the rotor shaft protruding from the axial end surface of the rotor core is crushed by using a predetermined caulking jig, and the rotor shaft is crushed along the axial end surface of the rotor core. Disclosed is a method for manufacturing a rotary electric rotor and a rotary electric rotor for forming a protrusion for fixing between the rotor core and the rotor shaft by expanding the rotor shaft outward from the outer periphery of the non-circular cross section. ..

JP-A-2019-75877

In the method for manufacturing a rotary electric rotor described in Patent Document 1, a part of a rotor shaft (rotor shaft) is crushed by using sheet metal stamping, and each member is fixed to each other by compressive stress. However, the fixing method as in Patent Document 1 has a problem that the fixing force of the portion where the members are fastened is insufficient.

The present invention has been made to solve such a problem, and provides a method for manufacturing a rotor shaft that improves the fixing force of a fastening portion between members.

In the method for manufacturing a rotor shaft according to an embodiment, a rotor shaft is manufactured by using a plate-shaped member to provide a protruding portion protruding in the outer peripheral direction and to form a hollow rotor shaft having a polygonal outer peripheral shape. In this method, a plate-shaped member is press-processed so as to extend from one end side in the width direction to the other end side in the width direction of the plate-shaped member, and a protruding portion protruding in the plate thickness direction of the plate-shaped member. A drawing process for forming a cross-sectional shape in which at least two U-shaped portions having a U-shaped cross section are connected in a cross section viewed from the length direction of the plate-shaped member orthogonal to the width direction of the plate-shaped member. It is formed by an anchor portion forming step and an anchor portion forming step of forming a concave portion on one end side in the width direction of the plate-shaped member and forming a convex portion that can be fitted so as to be caught in the concave portion on the other end side in the width direction. An anchor bending process that deforms the convex portion in the plate thickness direction of the convex portion, and a bending process that presses the portion where the cross sections of at least two U-shaped portions are connected to form a hollow plate-shaped member. It is provided with an anchor fitting step of fitting the convex portion into the concave portion while restoring the deformation applied to the convex portion.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a method for manufacturing a rotor shaft that improves the fixing force of a fastening portion between members.

It is a flowchart which shows the manufacturing method of the rotor shaft which concerns on Embodiment 1. It is a top view which shows the 1st molded article molded by the manufacturing method of the rotor shaft which concerns on Embodiment 1. FIG. FIG. 2 is a front sectional view taken along the line II-II of FIG. It is a side sectional view along the line III-III of FIG. It is a partial view which shows the shape of the anchor part formed in the manufacturing method of the rotor shaft which concerns on Embodiment 1. FIG. It is a top view which shows the 2nd molded article molded by the manufacturing method of the rotor shaft which concerns on Embodiment 1. FIG. FIG. 6 is a front sectional view taken along the line II-II of FIG. FIG. 3 is a front sectional view showing a third molded product molded by the method for manufacturing a rotor shaft according to the first embodiment. FIG. 5 is a front sectional view showing an intermediate stage of pressing in the method for manufacturing a rotor shaft according to the first embodiment. It is a front sectional view which shows the 4th molded article molded by the manufacturing method of the rotor shaft which concerns on Embodiment 1. FIG. It is a front sectional view which shows the rotor shaft manufactured by the manufacturing method of the rotor shaft which concerns on Embodiment 1. FIG. It is a perspective view of FIG.

Embodiment 1
Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention is not limited to the following embodiments. Further, in order to clarify the explanation, the following description and drawings are appropriately simplified. In the following description, the width direction of the plate-shaped member, the extending direction of the protruding portion is the direction orthogonal to the X direction, and the length direction of the plate-shaped member is the Y direction, the X direction, and the X direction. The plate thickness direction of the plate-shaped member is the Z direction, which is a direction orthogonal to both of the Y directions. Further, the shape along the XY plane defined by the X direction and the Y direction is defined as a planar shape, and the shape along the XZ plane defined by the X direction and the Z direction is defined as a cross-sectional shape.

FIG. 1 is a flowchart showing a method of manufacturing a rotor shaft according to the first embodiment. As shown in FIG. 1, the method for manufacturing a rotor shaft according to the present embodiment includes the following five steps S1 to S5.

In the drawing process of step S1, the plate-shaped member is pressed and extends from one end side in the width direction to the other end side in the width direction of the plate-shaped member, and protrudes in the plate thickness direction of the plate-shaped member. A cross section formed by connecting at least two U-shaped portions having a U-shaped cross section in a cross section viewed from a portion and a length direction of the plate-shaped member orthogonal to the width direction of the plate-shaped member. In the anchor portion forming step of step S2, a concave portion is formed on one end side in the width direction of the plate-shaped member, and a convex portion that can be fitted so as to be caught in the concave portion is formed on the other end side in the width direction. In the anchor bending step of step S3, the convex portion formed in the anchor portion forming step is deformed in the plate thickness direction of the convex portion. In the bending step of step S4, the plate-shaped member is formed into a hollow shape by pressing the portion where the cross sections of at least two U-shaped portions are connected to each other. In the anchor fitting step of step S5, the deformation applied to the convex portion is restored, and the convex portion is fitted into the concave portion.

Hereinafter, the above-mentioned process will be described in detail with reference to each figure corresponding to the flowchart of FIG. The method for manufacturing a rotor shaft according to the present embodiment is to process a work piece into a desired shape by press working. Pressing refers to a process of forming a member to be machined placed between a die and a punch while applying a compressive force or a tensile force so as to follow the shape of the die and the punch.

First, in the drawing process of step S1, the plate-shaped member is drawn to form the first molded product. The plate-shaped member is a material for a rotor shaft manufactured by the method for manufacturing a rotor shaft according to the present embodiment. As the plate-shaped member, a material that can be pressed and has the strength required for use as a rotor shaft can be used. Specifically, for example, a high-strength steel plate, a hot-forged steel plate, a cold-forged steel plate, a galvanized steel plate, or the like can be used. The material of each steel sheet includes metals such as iron, titanium, aluminum, magnesium and stainless steel, and composite materials of metal and resin. The plate-shaped member of the sheet metal has a substantially rectangular shape.

The shape of the first molded product obtained by drawing the plate-shaped member will be described with reference to FIGS. 2 to 4. FIG. 2 is a plan view showing a first molded product molded by the method for manufacturing a rotor shaft according to the first embodiment. FIG. 3 is a front sectional view taken along line II-II of FIG. FIG. 4 is a side sectional view taken along the line III-III of FIG.

As shown in FIG. 2, the planar shape of the first molded product 10 is substantially rectangular. When the plate-shaped member 1 of the sheet metal is drawn, for example, the outer peripheral portion of the first molded product 10 may be distorted. In that case, for example, as shown by the broken line in FIG. 2, the first molded product 10a in which the outer peripheral portion is distorted may be obtained. Further, the first molded product 10 extends in the X direction from one end side to the other end side in the width direction thereof, and has a protruding portion 11 protruding outward from the surface of the first molded product 10. The protrusion 11 is formed at a predetermined position in the Y direction of the plate-shaped member 1 over the entire plate-shaped member 1 from one end side to the other end side along the X direction. Further, the first molded product 10 has two U-shaped portions 12, 13 extending in the Y direction. The both end portions 14 and 15 of the first molded product 10 in the X direction are portions that have not been drawn. For both end portions 14 and 15, the end portion continuously formed from the U-shaped portion 13 is referred to as one end portion 15, and the end portion continuously formed from the U-shaped portion 12 is referred to as the other end portion 14.

It should be noted that the protrusion 11 is described in FIG. 2 as being continuously formed over the entire plate-shaped member 1 from one end side to the other end side in the X direction, but the present invention is not limited to this. For example, at a predetermined position in the Y direction of the plate-shaped member 1, the protruding portion 11 can be formed in a part of the plate-shaped member 1 in the X direction. In other words, intermittent protrusions 11, that is, a plurality of protrusions 11, can be formed on the same line in the X direction. When forming the plurality of protrusions 11, it is preferable to form the protrusions 11 so as to be arranged at equal intervals on the same line.

Each configuration of the first molded product 10 will be described with reference to FIGS. 3 and 4. First, the protruding portion 11 will be described with reference to FIG. The protruding portion 11 is formed by pushing a punch in a direction along the Z direction (downward in FIG. 4) with respect to the plate-shaped member 1 arranged on the die. As shown in FIG. 4, the protruding portion 11 thus formed has a substantially U-shaped shape that protrudes downward in the Z direction in FIG. 4 from the surface of the plate-shaped member 1 and opens upward in the Z direction. Have. The protrusion 11 can suppress the displacement of the rotor shaft in the rotation axis direction even when the rotor shaft rotates at high speed and an imbalance of the motor occurs when the motor including the rotor shaft, which is the final molded product, is driven. It is preferable to have a width W in the Z direction.

Next, the U-shaped portions 12 and 13 and the both end portions 14 and 15 will be described with reference to FIG. As shown in FIG. 3, the first molded product 10 has a cross-sectional shape in which two U-shaped portions 12 and 13 formed in a substantially U-shape are connected in a cross-sectional shape thereof.

Each U-shaped portion 12, 13 includes a wall portion and a bottom portion forming each side of a rotor shaft having a polygonal shape. More specifically, the U-shaped portion 12 includes wall portions 12a, 12c and a bottom portion 12b, and the U-shaped portion 13 includes wall portions 13a, 13c and a bottom portion 13b. When forming a polygonal rotor shaft whose sides are linear (each surface is flat), the wall portions 12a and 13a and the bottom portions 12b and 13b are flattened as shown in FIG. It is preferable to mold it into a shape. The wall portions 12c and 13c can be formed into a flat surface by pressing, which will be described later.

In the present embodiment, in order to form a rotor shaft having a polygonal outer peripheral surface, it is preferable to provide at least two U-shaped portions in the first molded product 10. The number of U-shaped portions can be appropriately changed according to the shape of the outer peripheral surface of the desired rotor shaft, that is, the shape of the inner peripheral surface of the rotor core (not shown) to which the rotor shaft is assembled. Further, as shown in FIG. 3, when two U-shaped portions are provided as an example, each U-shaped portion is line-symmetrical with respect to the portion where the cross sections of the adjacent U-shaped portions 12 and 13 are connected to each other. It is preferable to form 12 and 13. When three or more U-shaped portions are provided, each U-shaped portion may be formed so as to be line-symmetrical with the central portion in the X direction in a plurality of U-shaped portions connected to each other. preferable.

Then, the one end portion 15 of the first molded product 10 is in the X direction away from the end portion of the U-shaped portion 13 existing on the opposite side of the portion where the U-shaped portion 12 and the U-shaped portion 13 are connected to the U-shaped portion 12. Extend to. The other end 14 of the first molded product 10 is in the X direction away from the end of the U-shaped portion 12 existing on the opposite side of the portion where the U-shaped portion 12 and the U-shaped portion 13 are connected to the U-shaped portion 13. It is postponed.

In the drawing process, when the U-shaped portions 12 and 13 and the protruding portions 11 are formed on the plate-shaped member 1, the processing may be performed at the same timing using one type of die and punch, or they are different from each other. Processing may be performed at different timings using a die and a punch. The order in which the U-shaped portions 12 and 13 and the protruding portions 11 are processed is not limited, and any processing may be performed first.

In the anchor portion forming step of step S2, the first molded product 10 is punched, and the other end portion 14 of the first molded product 10 has a convex portion protruding in the X direction toward the outside of the plate-shaped member 1. Is formed, and a recess notched in the X direction toward the inside of the plate-shaped member 1 is formed in one end portion 15 of the first molded product 10. Here, an example of the shapes of the convex portion and the concave portion will be described with reference to FIG. FIG. 5 is a partial view showing the shape of the anchor portion formed in the method for manufacturing the rotor shaft according to the first embodiment. The left side of FIG. 5 shows one convex portion 17, and the right side of FIG. 5 shows one concave portion 18.

As shown on the left side of FIG. 5, the convex portion 17 has, for example, a substantially T-shaped planar shape along the XY plane, and the concave portion 18 has a convex portion 17 so as to correspond to the shape of the convex portion 17. It is formed as a notch with a slightly larger shape. In the present embodiment, as shown on the left side of FIG. 5, the anchor portion has a substantially T-shaped convex portion 17 having a substantially elliptical tip at a predetermined position in the Y direction of the plate-shaped member 1 at the other end. It is provided on the tip end side of the portion 14. Further, as shown on the right side of FIG. 5, at one end portion 15, a concave portion 18 which is a substantially T-shaped notch corresponding to the shape of the convex portion 17 is located at one end portion at a position parallel to each convex portion 17 in the X direction. It is provided on the tip side of 15.

The anchor portion composed of the convex portion 17 and the concave portion 18 is preferably formed into an anchor shape having a shape that allows the convex portion 17 to be fitted to the concave portion 18 so as to be hooked on the concave portion 18. The shape of the convex portion 17 and the concave portion 18 is not limited to a T-shape as in the present embodiment, but may be an L-shape or the like. By fitting the convex portion 17 and the concave portion 18 so as to be caught, the rotor is fitted. The fixing force of the fastening portion on the shaft can be increased, and the fastening portion can be fixed more firmly.

In the anchor portion forming step of step S2, punching is also performed on each side forming the outer periphery of the first molded product 10a in which the outer peripheral portion is distorted after the drawing process in step S1 to obtain the shape of the outer peripheral portion. It can be processed into a highly accurate rectangular shape. In the punching process, it is considered that the length along the shape of the molded product from the end face 14a of the other end 14 to the end face 15a of the one end 15 is the peripheral length of the rotor shaft so that the desired rotor shaft can be obtained. And punch out. Further, the formation of the anchor portion can be performed before the drawing process of step S1.

In the anchor bending step of step S3, the convex portion 17 formed in step S2 is deformed in the plate thickness direction (Z direction) of the convex portion 17 to form a second molded product. The shape of the second molded product will be described with reference to FIGS. 6 and 7. FIG. 6 is a plan view showing a second molded product molded by the method for manufacturing a rotor shaft according to the first embodiment. FIG. 7 is a front sectional view taken along line II-II of FIG.

As shown in FIG. 6, in the second molded product 20, both end portions 14 and 15 of the first molded product 10 shown by the broken line in FIG. 6 are punched out, and two protrusions are formed on the other end portion 14 of the second molded product 20. A portion 17 is formed, and two recesses 18 are formed in one end portion 15 of the second molded product 20. The two convex portions 17 are provided at positions different from the protruding portions 11 in the Y direction of the other end portion 14 so as to be separated from each other. The two concave portions 18 are provided at positions parallel to each of the two convex portions 17 in the X direction in the Y direction of the one end portion 15. In the present embodiment, it is composed of two sets of anchor portions, but is not limited to this. The number of anchor portions can be appropriately changed in consideration of the strength required for the rotor shaft and the like.

Then, as shown in FIG. 7, the convex portion 17 is pressed upward in the Z direction in FIG. 7, and the cross section along the XZ plane is deformed into a substantially L shape. The direction in which the convex portion 17 is deformed may be the Z direction, and may be the upward direction or the downward direction in FIG. 7. Further, the convex portion 17 can be deformed by using a punch or the like.

In the bending step of step S4, first, both ends 14 and 15 of the second molded product 20 are bent to form the third molded product. FIG. 8 is a front sectional view showing a third molded product molded by the method for manufacturing a rotor shaft according to the first embodiment. As shown in FIG. 8, both ends 14 and 15 (broken line portions) extending in the XY plane in the second molded product 20 extend to the YZ plane, for example, in the third molded product 30. Perform bending process. In other words, when the third molded product 30 becomes a hollow member having a polygonal outer peripheral shape through the pressing described below, the end surface 14a of the other end portion 14 and the end surface 15a of the one end portion 15 face each other. Both ends 14 and 15 are bent so that they can be contacted with each other. For example, as shown in FIG. 8, when the third molded product 30 has two U-shaped portions 12, 13 and both end portions 14, 15, the rotor shaft, which is the final molded product, has a substantially octagonal shape.

Subsequently, the portion where the cross sections of at least two U-shaped portions 12 and 13 are connected to each other is pressed to form a fourth molded product having a polygonal outer peripheral shape. In the present embodiment, as an example, a case where an octagonal rotor shaft finally composed of a combination of linear sides will be described will be described. The portion to be pressed in the present embodiment is near the apex of the connecting portion 16 of the adjacent U-shaped portions 12 and 13 in the third molded product 30 in which the U-shaped cross sections are connected to each other.

As shown in FIG. 8, the U-shaped cross sections are connected to each other to form a convex shape, and the height h of the connecting portion 16 is reduced (downward in the Z direction), and the connecting portion 16 has three shapes. It is plastically deformed until it has three sides that are planar, that is, linear. In other words, it is pressed until the height h of the connecting portion 16 finally becomes zero. The pressing of the connecting portion 16 can be performed by using, for example, a punch, a mandrel, or the like. The connecting portion 16 is pressed so as to form three of the eight sides of the octagonal rotor shaft.

Here, with reference to FIGS. 9 and 10, a stepwise change in the shape of the third molded product 30 to the fourth molded product due to the above-mentioned pressing will be described. FIG. 9 is a front sectional view showing an intermediate stage of pressing in the method for manufacturing a rotor shaft according to the first embodiment. FIG. 9 shows the third molded product 30 shown in FIG. 8 pressed. As shown in FIG. 9, the U-shaped cross sections are connected to each other, and in FIG. 9, the convex connecting portion 16 projecting upward in the Z direction is pressed downward in the Z direction, and the height h is stepwise. By reducing the amount to, the connecting portion 16 is plastically deformed.

Due to this plastic deformation, the U-shaped portions 12 and 13 move in an arc, respectively, and are pushed up in the direction of the black arrow shown in FIG. That is, by pressing the connecting portion 16, deformation occurs so that the relative positional relationship between the end face 14a and the end face 15a approaches. That is, by pressing the connecting portion 16, the end face 14a and the end face 15a can be deformed so as to be close to each other, and the convex portion 17 and the concave portion 18 corresponding to each other can be brought close to each other.

The third molded product 30 is molded into the fourth molded product shown in FIG. 10 through the state shown in FIG. FIG. 10 is a front sectional view showing a fourth molded product molded by the method for manufacturing a rotor shaft according to the first embodiment. As shown in FIG. 10, the cross-sectional shape of the fourth molded product 40 is substantially octagonal and hollow. In the fourth molded product 40, the connecting portion 16 is formed in a planar shape, and the connecting portion 16 is pressed so that the end face 14a and the end face 15a come into contact with each other until the height h of the connecting portion 16 becomes zero. Is. When the end face 14a and the end face 15a come into contact with each other, the contact surfaces are fixed to each other by the compressive stress generated in the contact surfaces of both. The convex portion 17 of the fourth molded product 40 is in a state of protruding downward in the Z direction from a surface extending in the XY plane composed of both end portions 14 and 15.

Here, "decreasing the height h stepwise" includes both continuous pressing until the height h becomes zero and intermittent pressing. "Performing intermittently" means reducing the height h to zero after several presses. Further, when each side of the outer peripheral shape of the polygonal shape of the rotor shaft, which is the final molded product, is a straight line, the rotor shaft is pressed until the height h becomes zero. For example, when each side has a curved portion, the height h can be appropriately adjusted according to the shape to form a desired shape.

The present embodiment has one of the features that the fixing force of the fastening portion of the rotor shaft can be improved by fitting the anchor portion in addition to the fixing of the contact surface by the above-mentioned compressive stress. The anchor fitting step of step S5 for fitting the anchor portion will be described with reference to FIGS. 11 and 12. FIG. 11 is a front sectional view showing a rotor shaft manufactured by the method for manufacturing a rotor shaft according to the first embodiment. FIG. 12 is a perspective view of FIG.

In the anchor fitting step of step S5, the convex portion 17 is fitted into the concave portion 18 by returning the deformation applied to the convex portion 17 in the anchor bending step of step S3 to the original state before the deformation. That is, as shown in FIG. 11, in the fourth molded product 40, the convex portion 17 protruding downward in the Z direction from the surface formed by both end portions 14 and 15 is in a state where the plane of the convex portion 17 is along the XY plane. Press upward in the Z direction to deform it. As a result, as shown in FIGS. 11 and 12, the convex portion 17 can be fitted and fitted into the concave portion 18. The rotor shaft 100 manufactured in this way is provided with a protruding portion 11 projecting in the outer peripheral direction, and has a substantially octagonal cross section composed of a combination of linear sides. In the anchor fitting step of step S5, when the deformation of the convex portion is restored, it is preferable to deform the convex portion so as to have a shape corresponding to the outer peripheral shape of the rotor shaft which is the final molded product.

As shown in FIG. 11, the radial thickness of each side of the rotor shaft 100 corresponds to the thickness of the member after drawing in step S1. Therefore, the rotor shaft 100 can be configured to have a uniform radial thickness.

Further, as shown in FIG. 12, the protruding portion 11 projects outward in the radial direction of the rotor shaft 100. Therefore, the outer diameter of the protruding portion 11 has an outer diameter larger than the outer diameter of the main body portion of the rotor shaft 100 other than the protruding portion 11. For example, in the present embodiment, the protrusion 11 is formed so as to go around the outer peripheral surface of the rotor shaft 100. With respect to the protrusion 11, even when the rotor shaft 100 rotates at high speed when the motor provided with the rotor shaft 100 is driven and an imbalance of the motor occurs, the displacement of the rotor shaft 100 in the rotation axis direction can be suppressed. In addition, the shape and arrangement position of the protruding portion 11 may be appropriately designed. A protruding portion 11, that is, a plurality of protruding portions 11 may be formed on the same outer periphery. It is preferable that the plurality of protrusions 11 are formed at equal positions on the same outer periphery of the rotor shaft 100.

Furthermore, the arrangement position of the protrusion 11 in the Y direction is not particularly limited. The protrusion 11 can be formed at a desired position in the Y direction according to the shape of the rotor core to which the rotor shaft 100 is assembled. Further, the number of protrusions 11 may be at least one, and it is possible to form two or more protrusions 11 depending on the shape of the rotor core.

As described above, by the steps S1 to S5, it is possible to manufacture a hollow rotor shaft having a projecting portion protruding in the outer peripheral direction from the plate-shaped member of the sheet metal and having a polygonal outer peripheral shape.

In the method for manufacturing a rotor shaft according to the present embodiment, a polygonal rotor shaft is manufactured. By forming the rotor shaft into a polygonal shape corresponding to the inner peripheral shape of the rotor core to be fastened to the rotor shaft, it is possible to prevent rotation in the circumferential direction between the rotor core and the rotor shaft as the rotor rotates.

Further, according to the method for manufacturing a rotor shaft according to the present embodiment, it is possible to manufacture a rotor shaft in which a protrusion is formed at a desired position from a plate-shaped member of a sheet metal by press working. The rotor shaft manufactured by the method for manufacturing a rotor shaft according to the present embodiment has a protruding portion formed on the outer peripheral portion thereof. When the rotor core and the rotor shaft are fastened, the protruding portion functions to regulate the displacement of the rotor shaft in the rotation axis direction due to the rotation of the rotor, and can fix the rotor core and the rotor shaft. By using press working as a molding method, the amount of material used and the machining process can be reduced as compared with the method of manufacturing a rotor shaft by forging molding, machining, or the like, so that the cost can be reduced.

Further, according to the method for manufacturing a rotor shaft according to the present embodiment, the rotor shaft can be formed in a hollow shape, and the thickness of the rotor shaft in the radial direction can be uniformly formed. Therefore, the weight of the rotor shaft can be reduced, and the occurrence of imbalance of the rotor shaft can be suppressed.

Further, in the method for manufacturing a rotor shaft according to the present embodiment, the fastening portion in the rotor shaft is formed by the compressive stress generated when both end faces of the plate-shaped member come into contact with each other and the anchor portion that can be fitted so as to be caught by each other. Fix it. The fastening portion fixed by such a fixing method can improve the fixing force of the fastening portion as compared with the fixing method using only compressive stress as in Patent Document 1, for example.

Further, such a fixing method can suppress an imbalance of the rotor shaft as compared with a method of joining the fastening portions of the rotor shaft by welding. Suppressing the imbalance of the rotor shaft has the effect of suppressing the vibration generated when the rotor rotates and improving the rotor performance.

1 Plate-shaped member 10 1st molded product 10a 1st molded product with distortion on the outer circumference 11 Protruding parts 12, 13 U-shaped parts 12a, 12c, 13a, 13c Wall parts 12b, 13b Bottom part 14 End part 15 One end part 14a, 15a End face 16 Connecting part 17 Convex part 18 Concave part 20 Second molded product 30 Third molded product 40 Fourth molded product 100 Rotor shaft h Height W Width

Claims (1)

A method for manufacturing a rotor shaft, which comprises a plate-shaped member, has a protruding portion protruding in the outer peripheral direction, and forms a hollow rotor shaft having a polygonal outer peripheral shape.
The plate-shaped member is press-processed so as to extend from one end side in the width direction of the plate-shaped member to the other end side in the width direction, and the protruding portion protruding in the plate thickness direction of the plate-shaped member. Drawing to form a cross-sectional shape in which at least two U-shaped portions having a U-shaped cross section are connected in a cross section viewed from the length direction of the plate-shaped member orthogonal to the width direction of the plate-shaped member. Process and
An anchor portion forming step of forming a concave portion on one end side in the width direction of the plate-shaped member and forming a convex portion that can be fitted into the concave portion on the other end side in the width direction.
An anchor bending step of deforming the convex portion formed in the anchor portion forming step in the plate thickness direction of the convex portion,
A bending step of forming the plate-shaped member into a hollow shape by pressing a portion where at least two cross sections of the U-shaped portion are connected to each other.
An anchor fitting step of undoing the deformation applied to the convex portion and fitting the convex portion into the concave portion,
A method of manufacturing a rotor shaft.

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