JP2018026971A - Manufacturing method of rotor steel plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of rotor steel plate suppressing the warping.SOLUTION: In a manufacturing method of rotor steel plate including a steel plate body (W11) having an opening (W12), and a bridge (W13) connecting the edges of the opening (W12), the bridge (W13) includes a bridge body (W13a), and opposite end parts (W13b, W13c) for connection with the opposite ends of the bridge body (W13a). The manufacturing method includes steps (ST2, ST22) of work hardening the bridge body (W13a) of the bridge (W13), while pressing the opposite end parts (W13b, W13c) of the bridge (W13).SELECTED DRAWING: Figure 2

Description

  The present invention relates to a method for manufacturing a rotor steel plate.

  There is a rotor for a motor with stacked electrical steel sheets. An example of such an electromagnetic steel plate includes a steel plate body having an opening for inserting a permanent magnet, and a bridge portion that connects a portion of the outer edge of the opening to a portion of the outer edge. This bridge portion may be work-hardened in order to ensure the mechanical strength necessary for the electromagnetic steel plate of the motor rotor. Patent Document 1 discloses such a specific example.

JP 2005-185081 A

  The electromagnetic steel sheet described above has excessive plastic flow along the longitudinal direction of the bridge portion due to work hardening of the bridge portion, and may be greatly warped as the electromagnetic steel plate of the rotor of the motor.

  A specific example of the above-described electromagnetic steel sheet will be described with reference to FIGS. 10 and 11. As shown in FIG. 9, the electromagnetic steel sheet 90 includes a disk-shaped steel sheet body 91 having an opening 92 for inserting a permanent magnet (not shown), and a part from one edge of the opening 92 to another edge. And a bridge portion 93 that connects the two. The electromagnetic steel plate 90 shown in FIG. 10 is described as a fan-shaped plate for easy understanding. The electromagnetic steel sheet 90 is formed by work hardening a work W90 (not shown). A large plastic flow is generated in the bridge portion 93 along the longitudinal direction, and the length of the bridge portion 93 in the longitudinal direction changes. As a result, as shown in FIG. 11, the electromagnetic steel sheet 90 may be bent in the height direction (here, the Z direction), that is, may be warped. In the rotor formed by laminating such electromagnetic steel plates 90, a gap may be generated between the electromagnetic steel plates 90, and the space factor may be reduced.

  The method for manufacturing a rotor steel plate according to the present invention suppresses the occurrence of warpage.

The manufacturing method of the manufacturing method of the rotor steel sheet according to the present invention is as follows:
A method of manufacturing a rotor steel plate comprising a steel plate body having an opening and a bridge portion connecting edges of the opening,
The bridge portion includes a bridge body and both ends connected to both ends of the bridge body,
A step of work hardening the bridge body of the bridge portion while pressing both ends of the bridge portion.
According to such a configuration, since the bridge portion is work-hardened in a state where the pressing portion presses the vicinity of both ends of the bridge portion, the occurrence of plastic flow is suppressed in the longitudinal direction of the bridge portion. Therefore, it can suppress that the length in the longitudinal direction of a bridge part becomes non-uniform | heterogenous, and can suppress generation | occurrence | production of the curvature in a rotor steel plate.

  The method for manufacturing a rotor steel sheet according to the present invention suppresses the occurrence of warpage.

FIG. 3 is a schematic diagram showing one step in a method for manufacturing a rotor steel plate according to Embodiment 1. FIG. 3 is a schematic diagram showing one step in a method for manufacturing a rotor steel plate according to Embodiment 1. It is a graph which shows the curvature height with respect to pad pressure. It is a top view which shows one specific example of the metal mold | die which can be utilized at 1 process of the manufacturing method of the rotor steel plate which concerns on Embodiment 1. FIG. It is sectional drawing which shows one specific example of the metal mold | die which can be utilized at 1 process of the manufacturing method of the rotor steel plate which concerns on Embodiment 1. FIG. It is a figure which shows the principal part of one specific example of the metal mold | die which can be utilized at 1 process of the manufacturing method of the rotor steel plate which concerns on Embodiment 1. FIG. It is an enlarged view which shows the principal part of one specific example of the metal mold | die which can be utilized at 1 process of the manufacturing method of the rotor steel plate which concerns on Embodiment 1. FIG. FIG. 6 is a top view showing one step of a modified example of the method for manufacturing a rotor steel plate according to Embodiment 1. It is sectional drawing which shows 1 process of the modification of the manufacturing method of the rotor steel plate which concerns on Embodiment 1. FIG. It is a figure which shows 1 process of the manufacturing method of a related rotor steel plate. It is a figure which shows 1 process of the manufacturing method of a related rotor steel plate.

Embodiment 1
With reference to FIG.1 and FIG.2, the manufacturing method of the rotor steel plate which concerns on Embodiment 1 is demonstrated. 1 and 2 are schematic views showing one step in the method for manufacturing a rotor steel plate according to Embodiment 1. FIG. 1 and 2, the right-handed three-dimensional xyz coordinates are defined.

  In this manufacturing method, a rotor steel plate is formed by processing a substantially disk-shaped electromagnetic steel plate W10 (see FIG. 1) as a workpiece. The example of the electromagnetic steel sheet W10 shown in FIG. 1 is described as a fan-shaped plate, specifically, a plate-shaped body obtained by dividing a substantially disk-shaped body into 16 equal parts at the center point for easy understanding.

  As shown in FIG. 1, the electromagnetic steel sheet W10 includes a steel sheet body W11 having an opening W12 and a bridge portion W13 that connects one part of the edge of the opening W12 to another part of the edge of the opening W12. The bridge portion W13 includes a bridge body W13a, one end W13b connected to one end of the bridge body W13a, and the other end W13c connected to the other end of the bridge body W13a. One end W13b connects one end of the bridge body W13a and one part of the edge of the opening W12, and the other end W13c connects one end of the bridge body W13a and another part of the edge of the opening W12.

  Moreover, in this manufacturing method, the press parts 21 and 22 (it is also called the pads 21 and 22), the punch 23 (refer FIG. 2), and the dice | dies 24 can be utilized. Specifically, the pressing portions 21 and 22 are substantially quadrangular prisms, and are movably disposed in the vicinity of one end W13b and the other end W13c of the bridge portion W13 of the electromagnetic steel plate W10. The pressing portions 21 and 22 can be moved so as to approach or move away from the die 24 by being driven from a driving source (not shown) such as a motor or a hydraulic cylinder. The die 24 is fixed at a predetermined position.

  First, the electromagnetic steel sheet W10 is pressed by pressing the pressing portions 21 and 22 against the electromagnetic steel sheet W10 in a state where the electromagnetic steel sheet W10 is disposed on the die 24 (pressing step ST1). Specifically, the pressing portion 21 presses one end W13b of the bridge portion W13, and the pressing portion 22 presses the other end W13c of the bridge portion W13. In other words, the pressing portion 21 and the die 24 sandwich and press the one end W13b of the bridge portion W13. The pressing portion 22 and the die 24 sandwich and press the other end W13c of the bridge portion W13. By these pressing pressures, the one end W13b and the other end W13c of the bridge portion W13 are maintained substantially the same thickness as the other portions of the bridge portion W13 without being recessed.

  Subsequently, as shown in FIG. 2, the punch 23 is pressed against the bridge portion W13, and the bridge portion W13, in particular, the bridge main body W13a is sandwiched between the punch 23 and the die 24 to be work-hardened (work-hardening step ST2). The punch 23 is disposed at a position away from the pressing part 21 by a distance L1 and from the pressing part 22 by a distance L2. While the pressing portion 21 presses one end W13b of the bridge portion W13, the bridge main body W13a is processed and cured while the pressing portion 22 presses the other end W13c of the bridge portion W13. Therefore, the occurrence of plastic flow is suppressed in the longitudinal direction of the bridge portion W13 (here, the x-axis direction). Therefore, it is possible to suppress the length of the bridge portion W13 in the longitudinal direction from becoming non-uniform, and to suppress the occurrence of warpage in the rotor steel plate 10. From the above, the rotor steel plate 10 can be manufactured.

  The work hardening step ST2 may be performed almost simultaneously with the pressing step ST1. Specifically, the pressing portion 21 presses one end W13b of the bridge portion W13, and the pressing portion 22 is the other end of the bridge portion W13. What is necessary is just to start work hardening of the bridge | bridging part W13 by the punch 23 in the state which pressed W13c.

  Further, it is preferable that at least one of the distance L1 and the distance L2 has a tendency to reduce the occurrence of warpage. This is because the shorter the distance L1 and the distance L2, the more the plastic flow due to work hardening is suppressed in the rotor steel plate 10.

  Moreover, the rotor (not shown) of a motor can be formed using the rotor steel plate 10 (not shown). The rotor steel plate 10 includes a steel plate body 11 (not shown), an opening portion 12 (not shown), and a bridge portion 13 (corresponding to the steel plate body W11, the opening portion W12, and the bridge portion W13 of the electromagnetic steel plate W10 (see FIG. 1). (Not shown). Specifically, after a plurality of rotor steel plates 10 are laminated, a rotor of a motor is formed by adding a necessary configuration such as inserting a magnet (not shown) into an opening 12 (not shown). Can do. Although the example of the opening part 12 shown in FIG. 1 is square shape, circular shape, etc., you may provide various shapes according to the shape of the magnet inserted. In the rotor steel plate 10, since generation | occurrence | production of curvature is suppressed, generation | occurrence | production of the clearance gap between the steel plate main bodies 11 is suppressed. Therefore, the rotor of the formed motor has a high space factor. Further, in order to manufacture a rotor of a motor using the rotor steel plate 10, resin may be injected between the magnet and the opening 12 to fix the magnet to the opening 12. In such a case, since the occurrence of gaps between the steel plate main bodies 11 is suppressed, the resin hardly leaks from the gaps between the steel plate main bodies 11, and the resin can be satisfactorily filled between the magnet and the opening 12. .

  Next, the detail of each process in the manufacturing method of the rotor steel plate which concerns on Embodiment 1 is demonstrated.

(Relationship between pad pressure and warp height)
In the pressing step ST1 and the work hardening step ST2, the relationship between the pad pressure and the warp height will be described.

  The pad pressure corresponds to a value obtained by dividing the force applied to the electromagnetic steel sheet W10 by the pressing parts 21 and 22 (pads 21 and 22) by the contact area between the pressing parts 21 and 22 and the electromagnetic steel sheet W10. is there. The warp height corresponds to a displacement before and after the work hardening step ST2 of a predetermined portion of the rotor steel plate 10, specifically, a portion corresponding to the outer edge of the rotor steel plate 10.

ここで、実施の形態１に係る回転子鋼板の製造方法のある一具体例について、パッド圧ＰｐをＰ_０、Ｐ_１、Ｐ_２、Ｐ_３としたときの反り高さＨ_０、Ｈ_１、Ｈ_２、Ｈ_３を計測し、それらの結果を図３に示した。
図３に示すように、パッド圧ＰｐをＰ_０から、Ｐ_１、Ｐ_２、Ｐ_３と順々に増大させた場合、反り高さＨｃは、Ｈ_０から、Ｈ_１、Ｈ_２、Ｈ_３と順々に減少した。図３に示すパッド圧Ｐｐの一例は、所定の基準値Ｐを１００％としたきの、Ｐ_０、Ｐ_１、Ｐ_２、Ｐ_３の相当する値である。パッド圧が増加すると、反り高さが減少する傾向にあると考えられる。これは、加工硬化による塑性流動が抑制されるためと考えられるからである。パッド圧が増加すると、反り高さが減少すると考えられて好ましい。但し、パッド圧は、電磁鋼板Ｗ１０を構成する材料の降伏応力よりも低いとよい。これは、押圧工程ＳＴ１において、電磁鋼板Ｗ１０に塑性変形を生じさせるのではなく、弾性変形させるためである。 Specifically, the pad pressure Pp [MPa] can be obtained using Equation 1 below. Formula 1 is a relational expression of the pad pressure Pp, the force Fd [N] of the driving source, and the product pressing area Ap [mm ² ]. The driving source force Fd corresponds to the force by which the driving source described above drives the pressing portions 21 and 22. The product pressing area Ap is an area where the pressing portions 21 and 22 are in contact with the electromagnetic steel sheet W10.

Here, for one specific example of the method for manufacturing a rotor steel plate according to the first embodiment, warp heights H ₀ , H ₁ when the pad pressure Pp is P ₀ , P ₁ , P ₂ , P ₃ , H ₂ and H ₃ were measured, and the results are shown in FIG.
As shown in FIG. 3, when the pad pressure Pp is increased sequentially from P ₀ to P ₁ , P ₂ , P ₃ , the warp height Hc is increased from H ₀ to H ₁ , H ₂ , H _3. And decreased in order. An example of the pad pressure Pp shown in FIG. 3 is a value corresponding to P ₀ , P ₁ , P ₂ , P ₃ when the predetermined reference value P is 100%. It is considered that as the pad pressure increases, the warp height tends to decrease. This is because the plastic flow due to work hardening is considered to be suppressed. As the pad pressure increases, the warp height is considered to decrease, which is preferable. However, the pad pressure is preferably lower than the yield stress of the material constituting the electromagnetic steel sheet W10. This is because, in the pressing step ST1, the electromagnetic steel sheet W10 is not plastically deformed but elastically deformed.

  The pad pressure Pp may be increased by reducing the product pressing area Ap. This is because the drive source that can be used is limited based on the size of the rotor steel plate 10, and therefore the reduction of the product pressing area Ap is easier than the increase of the force Fd of the drive source. .

(Example of manufacturing equipment)
With reference to FIGS. 4-7, the specific example of the metal mold | die which can implement the manufacturing method of the rotor steel plate which concerns on Embodiment 1 is demonstrated. FIG. 4 is a top view showing a specific example of a mold that can be used in one step of the method for manufacturing a rotor steel plate according to Embodiment 1. FIG. FIG. 5 is a cross-sectional view showing a specific example of a mold that can be used in one step of the method of manufacturing a rotor steel plate according to Embodiment 1. FIG. 6 is a diagram illustrating a main part of a specific example of a mold that can be used in one step of the method of manufacturing a rotor steel plate according to Embodiment 1. FIG. 7 is an enlarged view showing a main part of one specific example of a mold that can be used in one step of the method of manufacturing a rotor steel plate according to Embodiment 1.

  As shown in FIGS. 4 and 5, the mold 30 includes a punch holding plate 31, a die holding part 32, a punch 33, a die 34, and a pad unit 35. In the pressing step ST1 and the work hardening step ST2, the mold 30 can be used.

  The punch holding plate 31 holds the punch 33 and the pad unit 35. The punch 33 has a shape protruding in a U shape from the surface of the punch holding plate 31 (here, a surface substantially parallel to the xy plane), and has a molding surface for work hardening of the bridge portion W13 in the work hardening step ST2. Have.

  The pad unit 35 includes a gas spring holding plate 35a, a gas spring 35b, a plate 35c, a pad end 35d, a pad holding portion 35e, and a pad 35f.

  The gas spring holding plate 35a is installed on the main surface of the punch holding plate 31 on the punch 33 side, and holds the plate 35c via at least one gas spring 35b.

  The gas spring 35b is a spring using a gas medium. As shown in FIGS. 5 and 6, the plate 35c includes a pad holding portion 35e, and the pad holding portion 35e holds the pad 35f by inserting a knock pin into the flange portion 35i, for example. The pad 35f is a rod-shaped body and may be covered with a surface coating such as an insulating coating. The pad 35f includes a tip 35g and a flange portion 35i that is disposed at the root of the tip 35g and has a larger diameter than the tip 35g. The plate 35 c is pressed by the gas spring 35 b and presses the flange portion 35 i toward the punch 33. Here, the plate 35c and the punch 33 sandwich the flange portion 35i.

  The pad 35f is movably held by being inserted into the holding hole of the punch 33. It is preferable that the gap between the holding hole of the punch 33 and the side surface of the pad 35 f be sized so that the movement of the pad 35 f is guided by the punch 33. The pad end 35 d is disposed so as to be sandwiched between the plate 35 c and the punch 33. It is preferable to arrange the pad end 35d between the plate 35c and the punch 33. Accordingly, when the pressing step ST1 and the work hardening step ST2 are not performed, that is, when the punch 33 and the die 34 are not receiving a force toward the punch holding plate 31, the pad end 35d is a plate together with the flange portion 35i. Receives force and impact from 35c. Therefore, it is possible to suppress damage to the flange portion 35i by suppressing the force or impact applied to the flange portion 35i from the plate 35c.

  As shown in FIG. 6, the tip 35 g of the pad 35 f slightly protrudes from the molding surface 33 a of the punch 33. The distance from the molding surface 33a of the punch 33 to the tip 35g, that is, the punch stroke Ps is preferably short. This is because if the punch stroke Ps is short, the pad 35f is less likely to be damaged.

As shown in FIGS. 6 and 7, the tip 35g of the pad 35f preferably has a corner 35h. This is because the tip 35g of the pad 35f is difficult to break and the surface coating such as an insulating coating on the tip 35g is difficult to peel off.
The corner 35h is formed by intersecting the side surface of the pad 35f and the end surface of the tip 35g. The corner 35h is chamfered, and in the example shown in FIG. 7, the corner 35h has a curved surface with a predetermined radius R. The flange 35i of the pad 35f is pushed into the pad holding part 35e.

(Modification)
Next, with reference to FIG.8 and FIG.9, the modification of the manufacturing method of the rotor steel plate which concerns on Embodiment 1 is demonstrated. FIG. 8 is a top view showing one step of a modified example of the method of manufacturing a rotor steel plate according to Embodiment 1. FIG. 9 is a cross-sectional view showing one step of a modified example of the method of manufacturing a rotor steel plate according to Embodiment 1. The modification of the manufacturing method of the rotor steel plate according to Embodiment 1 has a common configuration except that the pressing pins 21a and 22a are used instead of the pressing portions 21 and 22 (see FIGS. 1 and 2). Is provided. This different configuration will be described.

  As shown in FIGS. 8 and 9, in the modified example of the manufacturing method, pressing pins 21 a and 22 a, a punch 23, and a die 24 can be used. Specifically, the pressing pins 21a and 22a are substantially cylindrical bodies, and are respectively disposed at one end W13b and the other end W13c of the bridge portion W13 of the electromagnetic steel plate W10. The cross-sectional shape of the pressing pins 21a and 22a is substantially circular, and the diameter is preferably larger than the width of the bridge body W13a of the bridge portion W13. The tips of the pressing pins 21a and 22a have a part of a spherical surface with a predetermined radius R, for example, a spherical crown surface, and the tip angles of the pressing pins 21a and 22a are preferably 45 °. The pressing pins 21 a and 22 a can be moved so as to approach or separate from the die 24 by being driven from a driving source (not shown) such as a motor or a hydraulic cylinder.

  The pressing pins 21a and 22a have a small contact area compared to the pressing parts 21 and 22 (see FIGS. 1 and 2), but press the one end W13b and the other end W13c with a sufficient contact area. Can do. Further, the pressing pins 21a and 22a have a small contact area as compared with the pressing portions 21 and 22, and thus are easy to handle.

  First, with the electromagnetic steel sheet W10 disposed on the die 24, the electromagnetic steel sheet W10 is pressed by pressing the pressing pins 21a and 22a against the electromagnetic steel sheet W10 (pressing step ST21). Specifically, the pressing pin 21a presses the one end W13a of the bridge portion W13, and the pressing pin 22a presses the other end W13b of the bridge portion W13. As shown in FIG. 9, the pressing pins 21a and 22a may be pressed against the electromagnetic steel sheet W10 so that the tips of the pressing pins 21a and 22a bite into the electromagnetic steel sheet W10. Moreover, the electromagnetic steel plate W10 is dented when the tips of the pressing pins 21a and 22a press the electromagnetic steel plate W10. Moreover, the stress which the pressing pins 21a and 22a press the electromagnetic steel plate W10 is good to be less than the yield stress of the material which comprises the electromagnetic steel plate W10. In other words, the pressing pins 21a and 22a may be pressed against the electromagnetic steel sheet W10 so that the electromagnetic steel sheet W10 is elastically deformed.

  Subsequently, the punch 23 is pressed against the bridge portion W13 so that the bridge portion W13 is sandwiched between the punch 23 and the die 24 and is work-hardened (work-hardening step ST22). In order to work and harden the bridge portion W13 while the pressing pin 22a presses while pushing the one end W13b of the bridge portion W13 while pressing the other end portion W13c of the bridge portion W13. The occurrence of plastic flow is suppressed in the longitudinal direction (here, the x-axis direction) of the bridge portion W13. Therefore, it can suppress that the length in the longitudinal direction of the bridge part W13 becomes non-uniform | heterogenous, and can suppress generation | occurrence | production of the curvature in the rotor steel plate 10 (not shown). From the above, the rotor steel plate 10 can be manufactured.

  Note that the present invention is not limited to the above-described embodiment, and can be changed as appropriate without departing from the spirit of the present invention.

ST1, ST21 Pressing step ST2, ST22 Work hardening step W10 Electrical steel plate W11 Steel plate body W12 Opening portion W13 Bridge portion W13a Bridge body W13b One end portion W13c The other end portion

Claims (1)

A method of manufacturing a rotor steel plate comprising a steel plate body having an opening and a bridge portion connecting edges of the opening,
The bridge portion includes a bridge body and both ends connected to both ends of the bridge body,
Including the step of work hardening the bridge body of the bridge portion while pressing the both ends of the bridge portion;
Manufacturing method of rotor steel plate.

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