JP2006353027A - Rotor for permanent-magnet generator, and formation method for reluctor thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for forming a reluctor wherein a machining time can be shortened and waste of material can be avoided, further the thickness of a yoke sidewall can be reduced, and the height for the reluctor can be easily ensured. <P>SOLUTION: A reluctor 7 is formed on the outer circumferential surface of a yoke sidewall 4b of a rotor for permanent-magnet generators, in which a boss and a closed-end cylindrical yoke 4 are formed integrally. The yoke sidewall 4b is disposed between high-frequency coils 21a, 21b and is subjected to high-frequency induction heating. Thereafter, the sidewall 4b is cooled in the air to carry out normalizing. After the normalizing, the reluctor 7 is punched out of the sidewall 4b, from the inner circumferential surface side outward in the radial direction. Since the sidewall 4b has been softened by the normalizing at this time, the reluctor can be formed easily by press work, thus a machining time is shortened, and waste of material is avoided. In addition, the accuracy of forming the reluctor 7 is enhanced, and the accuracy of detection of engine ignition timing is enhanced, as well. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a magnet generator used in a motorcycle or the like, and more particularly, to a technology for forming a rotor in a magnet generator that performs a power generation operation in cooperation with an engine.

  As a generator mounted on a motorcycle or the like, a magnet generator using a permanent magnet and a coil is widely used because a high output can be obtained with a simple structure. This type of magnet generator includes a stator around which a generator coil is wound, and a rotor that is rotatably supported on the outside of the stator. The stator is attached to the engine body, and the rotor Is fixed to the crankshaft of the engine. The rotor is provided with a yoke made of a magnetic material, and a plurality of permanent magnets are attached to the inner surface side of the yoke. When the engine is started, a rotor provided with a permanent magnet rotates around the stator, and an electromotive force is generated in the generator coil to generate power.

  Many of the magnet generators attached to the engine have a rotor on the side of the rotor that protrudes from the side of the rotor for adjusting the ignition timing of the engine. In this case, an ignition timing sensor that outputs a signal when it is opposed to the reluctator is disposed in the vicinity of the yoke. The ignition timing sensor includes an iron core around which a coil is wound, and a permanent magnet that forms a magnetic flux passing through the iron core. When the magnetic pole of the iron core faces the reluctator as the crankshaft rotates, an induced electromotive force is generated in the coil due to a change in magnetic flux in the iron core, and a pulse signal is output from the ignition timing sensor. On the engine control side, the engine rotation angle (phase) is detected based on this signal, and the ignition timing is controlled.

  On the other hand, in such a magnet generator, conventionally, a yoke and boss separate configuration in which a yoke and a boss are separately formed and joined by a rivet or the like is mainly used. For the boss, a hot forged product such as S45C is used. Further, in the separate magnet generator, as shown in FIG. 6A, the above-mentioned reluctator 51 is formed on the side surface of the yoke 52 by pressing. However, there are the following problems when a reluctator is formed by press working. (1) The reluctator cannot be formed with high accuracy and the ignition timing may be erroneously detected. (2) When punched with high load, there is a risk of damage to weak parts. For this reason, it is difficult to ensure the height of the reluctator sufficiently, which also contributes to erroneous detection. (3) Since the strength of the yoke material is low, the thickness of the yoke side wall cannot be reduced. For this reason, the outer diameter of the yoke is increased and the layout is restricted.

On the other hand, in recent years, from the viewpoints of reluctator molding accuracy, freedom of rotor shape, layout, etc., a yoke / boss integrated magnet in which the boss and yoke are integrally formed by hot forging S45C, etc. Generators are increasing. In this case, since the yoke is formed by forging, it has a high hardness and is difficult to press unlike a rolled mild steel sheet such as SPH. In addition, since the boss portion is integrally formed at the yoke central portion, a general press working machine cannot be used for launching the reluctator. For this reason, as shown in FIG. 6 (b), yoke blanks 54a and 54b and a retractor cutting allowance 55 are provided in advance in the yoke blank 53, and a retractor 57 is formed on the outer peripheral surface of the yoke 56 by cutting. . Moreover, in the magnet rotor of patent document 1, the protrusion for forming a reluctator is provided in the outer periphery of a yoke, and the reluctator is formed in the yoke outer peripheral surface by cutting this.
JP 11-355989 A Japanese Patent Publication No. 7-50978

  However, when a reluctator is formed by cutting as described above, there are the following problems. (1) An extra plate thickness of the yoke must be ensured by the amount of cutting, which increases the material cost and wastes the material by the amount of cutting. (2) Since it is formed by a composite processing machine or the like, the processing time becomes long and the cost is high. In particular, when many reluctors are required, the processing time becomes long and the cost is high. (3) Productivity is poor because a dedicated cutting process is required. (4) The structure of the yoke itself is complicated because the protrusion for forming the relaxor is provided. (5) In order to ensure the dimensional accuracy of the yoke inner diameter, it is necessary to finish the inner diameter (in the case of press work, the yoke inner diameter is finished by pressing, so no cutting is performed). However, since (5) is premised on the cutting finish, the inner diameter finish cutting is performed after the formation of the relaxor, so that it is possible to realize a height of the retractor that is greater than the thickness of the yoke side wall without adding a process. is there.

  Therefore, in the device of Patent Document 2 by the present applicant, the device configuration is devised so that a reluctator can be formed by press working in order to solve the problems (1), (3), and (4) described above. That is, first, the yoke is mounted on the outer peripheral surface of the fixed punch, and the die is disposed on the outer peripheral side of the yoke so that the concave portion of the die and the protruding portion of the fixed punch face each other through the yoke. Then, the die is moved in the radial direction of the yoke in a state where the protruding portion is in contact with the outer peripheral surface of the yoke and the die is in contact with the outer peripheral surface of the yoke. As a result, even if the protrusion is fitted into the yoke, the reluctator is driven out on the outer periphery of the yoke, and the boss is at the center of the yoke, it is possible to project the reluctator on the outer peripheral surface of the yoke by pressing.

  However, even when a device such as Patent Document 2 is used, the forged yoke has a high hardness, so it cannot be said that it is necessarily good in terms of workability, and it is costly in terms of yield and die life. There was a problem of being disadvantageous. In addition, in order to sufficiently secure the height of the reluctator, a high-load press work is required, and there is a problem that if the workability is prioritized, the height of the reluctator cannot be secured. As described above, both cutting and pressing work have merits and demerits, and there has been a demand for a method of forming a relaxor that can realize both advantages.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a method for forming a relaxor that can shorten the processing time, eliminate waste of material, and reduce the thickness of the yoke side wall so that the height of the relaxer can be easily secured.

  A method of forming a rotor for a rotor for a magnet generator according to the present invention includes a boss part attached to a crankshaft of an engine, a bottom wall part provided integrally with the boss part, and extending radially outward from the boss part, A bottomed cylindrical yoke having a cylindrical side wall portion extending in the axial direction from the outer end of the bottom wall portion, and radially outward from the outer peripheral surface to the outer peripheral surface of the side wall portion. A method of forming the relaxor of a rotor for a magnet generator in which a projecting relaxor is formed, the hardness adjusting step of adjusting the hardness of the side wall part, and from the inner peripheral surface side of the side wall part radially outward Then, the present invention is characterized by comprising a reluctor forming step of punching out the reluctor.

  In the present invention, after adjusting the hardness of the yoke side wall in the hardness adjusting step, the retractor is punched out in the relaxer forming step, so that the workability of the yoke is improved and the retractor is easily press formed. It becomes possible. For this reason, as compared with the cutting process, the processing time required for forming the relaxor is shortened, and the waste of material is reduced. Further, the processing load at the time of forming the relaxor is reduced, and the forming accuracy of the relaxor is improved.

  In the method of forming a rotor for a magnet generator, the hardness of the side wall portion may be reduced by normalizing the side wall portion in the hardness adjusting step. The hardness of the yoke side wall may be adjusted by high-frequency induction heating of the side wall in the hardness adjusting step.

  In the method for forming a rotor for a magnet generator rotor, a yoke thickness adjusting step for adjusting a plate thickness of the side wall portion may be further provided after the reluctor forming step. In this case, the thickness of the side wall portion may be reduced by cutting the inner peripheral surface of the side wall portion in the yoke thickness adjusting step. As a result, the yoke side wall thickness can be made smaller than the height of the retractor.

  On the other hand, a rotor for a magnet generator according to the present invention includes a boss portion attached to a crankshaft of an engine, a bottom wall portion provided integrally with the boss portion and extending radially outward from the boss portion, and the bottom wall. A cylindrical yoke with a bottom having a cylindrical side wall extending in the axial direction from the outer end of the portion, and projecting radially outward from the outer peripheral surface on the outer peripheral surface of the side wall A rotor for a magnet generator in which a reluctator is formed, wherein the side wall portion of the yoke has a low hardness portion formed to have a lower hardness than the boss portion, and the reluctator has the low hardness portion. It is formed in these. In this case, the entire side wall portion may be the low hardness portion.

  In the present invention, the yoke side wall portion is provided with a low hardness portion having a hardness lower than that of the boss portion, and the relaxor is formed there. Therefore, the relaxor can be easily formed by press working. For this reason, as compared with the cutting process, the processing time required for forming the relaxor is shortened, and the waste of material is reduced. Further, the processing load at the time of forming the relaxor is reduced, and the forming accuracy of the relaxor is improved.

  In the method for forming a rotor of a rotor for a magnet generator according to the present invention, a magnet generator in which a boss portion and a bottomed cylindrical yoke are integrally formed, and a retractor is projected from the outer peripheral surface of the yoke side wall portion. When forming the rotor for the rotor, the hardness of the yoke side wall is adjusted in the hardness adjustment process, and then the retractor is punched out in the process of forming the retractor. This improves the workability of the yoke and makes it easy to press the retractor. It becomes possible to do. For this reason, it is possible to shorten the processing time required for the formation of the relaxor and to eliminate waste of materials as compared with cutting. Therefore, it is possible to reduce the manufacturing man-hours and material costs of the relaxor, and to reduce the product cost.

  In addition, because the workability of the yoke is improved, it is possible to reduce the processing load at the time of forming the reluctor, and it is possible to press-mold the reluctator without damaging the yoke without applying a high load when launching the reluctator. Become. Accordingly, the product yield can be improved and the height of the reluctator can be increased. Furthermore, since the forming accuracy of the relaxer is also improved, the detection accuracy of the engine ignition timing can be improved in combination with the increase in the height of the relaxor.

  In addition, by providing a yoke thickness adjusting step for adjusting the plate thickness of the side wall portion after the relaxor forming step, the yoke side wall thickness can be made smaller than the height of the retractor. As a result, the yoke can be thinned, and the layout of the magnet generator can be improved.

  On the other hand, in the rotor for a magnet generator according to the present invention, the rotation for a magnet generator in which a boss portion and a bottomed cylindrical yoke are integrally formed and a reluctator is provided on the outer peripheral surface of the yoke side wall portion. In the child, the yoke side wall portion is provided with a low hardness portion having a hardness lower than that of the boss portion, and the relaxor is formed there. Therefore, it is possible to easily form the relaxor by press working. For this reason, it is possible to shorten the processing time required for the formation of the relaxor and to eliminate waste of materials as compared with cutting. Therefore, it is possible to reduce the manufacturing man-hours and material costs of the relaxor, and to reduce the product cost.

  In addition, because the workability of the yoke is improved, it is possible to reduce the processing load at the time of forming the reluctor, and it is possible to press-mold the reluctator without damaging the yoke without applying a high load when launching the reluctator. Become. Accordingly, the product yield can be improved and the height of the reluctator can be increased. Furthermore, since the forming accuracy of the relaxer is also improved, the detection accuracy of the engine ignition timing can be improved in combination with the increase in the height of the relaxor.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a sectional view of a magnet generator using a rotor to which a method for forming a relaxor according to an embodiment of the present invention is applied, and FIG. 2 is a front view of the magnet generator of FIG. The magnet generator 1 shown in FIGS. 1 and 2 includes a stator 2 and a rotor 3 and is mounted on a motorcycle. The stator 2 is fixed to an engine case (not shown) of the engine, and the rotor 3 is connected to an engine crankshaft (not shown). The rotor 3 is configured to serve as both a generator field element and an engine flywheel. When the engine starts and the crankshaft rotates, the rotor 3 rotates around the stator 2.

  The rotor 3 includes a bottomed cylindrical yoke 4 and a boss portion 5 attached to a crankshaft of the engine. The yoke 4 is provided integrally with the boss portion 5 and is formed by hot forging using a magnetic material such as iron (for example, S45C). The yoke 4 includes a bottom wall portion 4a extending radially outward from the outer periphery of the boss portion 5, and a cylindrical side wall portion formed coaxially with the boss portion 5 from the outer end of the bottom wall portion 4a and extending along the axial direction. 4b is provided. A plurality (20 in this embodiment) of permanent magnets 6 are attached to the inner peripheral surface 4c of the yoke 4 along the circumferential direction with an adhesive or the like. On the other hand, the outer peripheral surface of the yoke side wall part 4b is formed with a relaxer 7 that protrudes outward in the radial direction. A tapered portion 5a is formed in the boss portion 5, and is taper-coupled to the crankshaft and fastened by a bolt or the like (not shown). Thereby, the rotor 3 rotates integrally with the crankshaft.

  The stator 2 includes a core 11 formed by laminating a large number of steel plates. The core 11 is arranged concentrically with the crankshaft on the outer surface of the engine case, and is fixed to the engine case with bolts 12. Outside the stator 2, the rotor 3 is rotatably arranged so as to surround the outer periphery thereof. The core 11 includes an annular core body 13 and a plurality of salient poles 14 that project radially from the outer periphery of the core body 13. A generator coil 15 is wound around each salient pole 14. The generator coil 15 is connected to a battery and a load (both not shown) via a rectifier, a voltage regulator and the like.

  Thus, in the magnet generator 1 in which the yoke 4 and the boss portion 5 are integrally formed by hot forging, as described above, the hardness of the yoke 4 is high and it is difficult to press-mold the retractor 7. Therefore, the present inventors pay attention to the fact that the yoke 4 does not require a higher strength than the boss portion 5, and provides a hardness adjusting step to reduce the hardness of the side wall portion 4 b to such an extent that press working is possible. As a result, the side wall portion 4b can be easily pressed, and the retractor 7 can be press-molded by a yoke / boss integrated magnet generator.

  FIG. 3 is an explanatory view showing steps of a relaxor forming method that is Embodiment 1 of the present invention. In the relaxor forming method of the present invention, the normalizing process is performed on the side wall portion 4b of the yoke 4 by the high frequency coils 21a and 21b in the hardness adjusting step shown in FIG. The high frequency coils 21a and 21b are formed in a double cylindrical shape, and the side wall portion 4b is mounted between the high frequency coils 21a and 21b. From the high frequency coils 21a and 21b, an alternating current of about 30 to 100 Hz, for example, is supplied over the entire circumference of the side wall 4b. Thereby, a high-density eddy current is generated in the vicinity of the inner and outer surfaces of the side wall 4b, and the side wall 4b is heated by the Joule heat. By this high frequency induction heating, the side wall 4b is heated to a temperature equal to or higher than the transformation point, and then cooled in the atmosphere. By this normalizing process, the hardness of the side wall 4b is reduced from about HRC25-30 to about HRC15.

  After normalizing the side wall part 4b, a relaxor molding step is performed. In the relaxer forming step, for example, the reluctator 7 is formed by stamping from the yoke inner peripheral surface 4c side with a press device as shown in Patent Document 2 (FIG. 3C). At this time, since the hardness of the side wall portion 4b is lower than that after forging, the reluctator 7 can be press-molded relatively easily. According to the experiments by the inventors, the workability could be greatly improved by softening the side wall portion 4b to about HRC15 by normalization. The required strength of the yoke 4 can be sufficiently maintained if it has a hardness of about HRC15.

  Thus, by improving the workability of the yoke 4 and enabling the reluctator 7 to be press-molded, the processing time can be shortened compared to the cutting process, and the waste of materials can be saved. Therefore, it is possible to reduce the manufacturing man-hours and material costs of the reluctor 7, and it is possible to reduce the product cost. In addition, since the workability is improved, the height of the reluctator can be sufficiently secured, and the detection accuracy of the ignition timing can be improved.

  Next, a method for forming a relaxor that is Embodiment 2 of the present invention will be described. FIG. 3 is an explanatory diagram showing the process. The configuration of the magnet generator itself is the same as that of the first embodiment, and the same members and portions as those of the first embodiment are denoted by the same reference numerals and the description thereof is omitted.

  Here, like the yoke blank 53 of FIG. 6, the machining allowances 22a and 22b are set in advance on the inner and outer circumferences of the yoke side wall 4b. The process of forming the relaxer 7 is the same as that in the first embodiment. After the side wall 4b is softened by the high frequency coils 21a and 21b, the relaxer 7 is formed by pressing. As a result, the processing time can be shortened and the material cost can be reduced as described above. In this embodiment, a yoke thickness adjusting step is provided after the press working, and the machining allowances 22a and 22b are removed by cutting to finish the inner and outer peripheral dimensions of the yoke 4. As described above, when the yoke 4 is a forged product, it is necessary to finish the inner diameter in order to ensure dimensional accuracy, and the method of Example 2 is applied in the actual manufacturing process.

  When the yoke 4 is finished by cutting in this way, for example, by setting a larger machining allowance 22b on the inner diameter side, the height of the reluctator 7 can be made equal to or greater than the plate thickness of the side wall portion 4b without any additional process. FIG. 5 is an explanatory diagram showing a processing step for forming the height of the reluctator to be equal to or greater than the thickness of the yoke side wall. In FIG. 5, the inner peripheral side of the side wall part 4b is further cut from the state of FIG. 4 (c). That is, the machining allowance 22c shown in the left diagram of FIG. 5 is further cut during the inner diameter finishing, and the plate thickness t1 of the side wall portion 4b becomes smaller than the height t2 of the retractor 7 as shown in the right diagram of FIG. Thereby, the yoke side wall thickness can be made smaller than the height of the retractor, the yoke 4 can be made thinner, and the layout of the magnet generator 1 can be improved. In addition, the cutting process of FIG.4 (c) and the cutting process of FIG. 5 are implemented continuously.

It goes without saying that the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention.
For example, in the above-described embodiment, an example is shown in which one reluctor 7 is formed on the yoke side wall portion 4b. However, the present invention can also be applied to a case where a plurality of reluctors 7 are formed. In the above-described embodiment, the side wall portion 4b is heated and softened over the entire circumference, and the entire side wall portion 4b becomes a low hardness portion. However, only the portion that forms the reluctator 7 is softened and reduced. The hardness portion may be partially formed. That is, in the above-described embodiment, only the vicinity of the portion where the reluctator 7 is formed may be softened so as to be a low hardness portion. In addition, when a low hardness part is formed in all or a part of the side wall part 4b, the influence on the strength required for the yoke 4 is almost the same in any case. It is more advantageous to heat and soften.

1 is a cross-sectional view of a magnet generator using a rotor to which a method for forming a relaxor according to an embodiment of the present invention is applied. It is a front view of the magnet generator of FIG. It is explanatory drawing which shows the process of the relaxor formation method which is Example 1 of this invention. It is explanatory drawing which shows the process of the relaxor formation method which is Example 2 of this invention. It is explanatory drawing which shows the process process which forms a reluctator height more than the board thickness of a yoke side wall part. (A) is explanatory drawing which shows the process of forming a reluctor by press work, (b) is explanatory drawing which shows the process of forming a reluctor by cutting.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Magnet generator 2 Stator 3 Rotor 4 Yoke 4a Bottom wall part 4b Side wall part 4c Inner peripheral surface 5 Boss part 5a Tapered part 6 Permanent magnet 7 Retractor 11 Core 12 Bolt 13 Core main body 14 Salient pole 15 Emitter coil 21a, 21b High-frequency coils 22a and 22b Cutting allowance 22c Cutting allowance 51 Retractor 52 Yoke 53 Yoke blanks 54a and 54b Yoke cutting allowance 55 Retractor cutting allowance 56 Yoke 57 Relaxor

Claims (7)

A boss attached to the crankshaft of the engine;
A bottomed cylindrical shape including a bottom wall portion that is provided integrally with the boss portion and extends radially outward from the boss portion, and a cylindrical side wall portion that extends along the axial direction from the outer end of the bottom wall portion. Having a yoke,
The method for forming the relaxor of the rotor for a magnet generator, wherein a relaxor that protrudes radially outward from the outer peripheral surface is formed on the outer peripheral surface of the side wall portion,
A hardness adjusting step for adjusting the hardness of the side wall,
A method of forming a relaxor for a rotor for a magnet generator, comprising a step of forming a relaxor from the inner peripheral surface side of the side wall portion toward the radially outer side.   2. The magnet generator according to claim 1, wherein the hardness adjusting step reduces the hardness of the side wall portion by normalizing the side wall portion in the hardness adjusting step. A method for forming a machine rotor.   The method of forming a rotor for a magnet generator according to claim 1 or 2, wherein, in the hardness adjustment step, the side wall portion is subjected to high frequency induction heating.   The method of forming a rotor for a magnet generator according to any one of claims 1 to 3, further comprising a yoke thickness adjusting step of adjusting a plate thickness of the side wall portion after the relaxor forming step. A method of forming a rotor for a rotor for a magnet generator.   5. The method of forming a rotor of a rotor for a magnet generator according to claim 4, wherein, in the yoke thickness adjusting step, the thickness of the side wall portion is reduced by cutting an inner peripheral surface of the side wall portion. A method of forming a rotor for a rotor for a magnet generator. A boss attached to the crankshaft of the engine;
A bottomed cylindrical shape including a bottom wall portion that is provided integrally with the boss portion and extends radially outward from the boss portion, and a cylindrical side wall portion that extends along the axial direction from the outer end of the bottom wall portion. Having a yoke,
On the outer peripheral surface of the side wall portion, a rotor for a magnet generator in which a reluctator that protrudes radially outward from the outer peripheral surface is formed,
The side wall portion of the yoke has a low hardness portion formed at a lower hardness than the boss portion,
The rotor for a magnet generator, wherein the relaxor is formed at the low hardness portion.   The rotor for a magnet generator according to claim 6, wherein the entire side wall portion is the low hardness portion.

Images