JP2021158811A - Rotary electric machine and manufacturing method of rotor - Google Patents

Abstract

To provide a rotary electric machine and manufacturing method of a rotor in which a boundary part of different magnetic poles in one magnet can be made clear, and a variation of characteristics from one product to another can be suppressed.SOLUTION: The rotary electric machine has a first magnetizing part 34b facing U-phase, V-phase, and W-phase sensors Su, Sv, Sw, and a second magnetizing part 34c facing a rotation sensor Sr. In a two-stage magnet 34 where magnetic poles of the first and second magnetizing parts 34b, 34c are made different from each other, between the first magnetizing part 34b and the second magnetizing part 34c along an axial direction of a rotor 30 of the two-stage magnet 34, a different density part 34d having a magnetic force (N-weaker) weaker than that of the first and second magnetizing parts 34b, 34c is provided.SELECTED DRAWING: Figure 5

Description

The present invention relates to a rotary electric machine including a stator on which a plurality of coils are wound and a rotor that rotates with respect to the stator.

Conventionally, a rotary electric machine (for example, a starter motor or an ACG starter) has been used to start an engine of a motorcycle or the like. The ACG starter operates as a starter motor that rotates the crankshaft when the engine is started, and operates as a generator that charges the in-vehicle battery after the engine is started. In addition, the ACG starter used to start the engine of motorcycles and the like detects the ignition timing and fuel injection timing (for example, the top dead center of the piston), and ignites the optimum plug for the in-vehicle controller and injects fuel. I try to let you.

For example, Patent Document 1 describes a starting motor (rotary electric machine) used for starting an engine. This starting motor includes a stator having coils corresponding to U-phase, V-phase, and W-phase, and a rotor fixed to a crankshaft. The rotor is provided with an annular magnet facing the stator, and the magnet is magnetized so that N poles and S poles appear alternately in the rotation direction of the rotor.

Further, three sensors (magnetic detectors) corresponding to the U phase, the V phase, and the W phase are provided on the portion of the stator facing the magnet (non-rotating portion). As a result, a drive current is supplied to each coil corresponding to the U phase, the V phase, and the W phase at a predetermined timing, and the coil is driven as a starter motor.

Further, only one of the plurality of magnets is provided with a different polar magnetic portion of a magnetic pole different from the reference magnetic pole, and one of the three sensors is opposed to the different polar magnetic portion. As a result, a square wave signal due to the different polar magnetic part is output once while the rotor makes one rotation, and this square wave signal is used for the ignition of the plug and the timing of fuel injection.

Japanese Unexamined Patent Publication No. 2013-102667

By the way, as in the technique described in Patent Document 1 described above, in order to provide a different polar magnetic portion in a magnet, a small magnetizing coil or the like (magnetizing device) is opposed to a relatively small portion to magnetize the magnet. It is necessary to pass a large current (magnetizing current) through the coil. In this case, the boundary between the magnetic poles of the different polar magnetic part and the magnetic poles of other parts may become unclear. That is, it is possible that the magnetic poles of other parts around the different polar magnetic portion become vaguely the magnetic poles of the different polar magnetic portion. As a result, the detection timing of the magnetic pole (N pole / S pole) by the magnetic detector varies from product to product, which in turn varies the drive efficiency of the starter motor, and the timing of ignition of the plug and injection of fuel. Can occur.

An object of the present invention is to provide a method for manufacturing a rotary electric machine and a rotor, in which the boundary between different magnetic poles in one magnet is clarified and the characteristics are suppressed from being dispersed for each product.

The rotary electric machine of the present invention is a rotary electric machine including a stator on which a plurality of coils are wound and a rotor that rotates with respect to the stator, and is provided on the stator and arranged in the rotation direction of the rotor. The three first magnetic detection units arranged in the above, the second magnetic detection unit provided on the stator and arranged so as to be displaced in the axial direction of the rotor with respect to the first magnetic detection unit, and the rotor. The plurality of magnets provided in the above, facing the first and second magnetic detection units, and arranged so that N poles and S poles appear alternately in the rotation direction of the rotor. One of them has a first magnetizing part facing the first magnetic detection part and a second magnetizing part facing the second magnetic detection part, and magnetic poles of the first and second magnetizing parts. The first and second magnetized portions are between the first magnetized portion and the second magnetized portion along the axial direction of the rotor of the two-stage magnet. It is characterized in that a different density portion having a magnetic force weaker than or having no magnetic force is provided.

The method for manufacturing a rotor of the present invention is a method for manufacturing a rotor that rotates with respect to a stator, and is a first magnetized portion and a second magnetized portion that are magnetized to magnetic poles that are different from each other in the axial direction of the rotor. And has a different density portion between the first magnetized portion and the second magnetized portion that is magnetized or not magnetized by a magnetic force weaker than that of the first and second magnetized portions. A magnet material preparation step for preparing one two-stage magnet material and a plurality of standard magnet materials not provided with different density portions, and arranging the two-stage magnet material and the standard magnet material in the circumferential direction of the rotor. The magnet material fixing step of fixing to the rotor, the magnetizing device is set on the two-stage magnet material fixed to the rotor and the portion of the standard magnet material facing the stator, and the standard magnet material is used on the rotor. The magnetism is performed so that different poles appear alternately in the rotation direction, and the portion of the two-stage magnet material provided with the different density portion is used as a boundary portion, and the portion facing the first magnetic detection portion provided on the stator is used. It has a magnetizing step of magnetizing a first magnetizing portion to one magnetic pole and magnetizing the second magnetizing portion facing the second magnetic detecting portion provided on the stator to another magnetic pole. It is characterized by.

In another aspect of the present invention, the length dimension of the first magnetized portion with respect to the axial direction of the rotor is larger than the length dimension of the second magnetized portion with respect to the axial direction of the rotor. ..

In another aspect of the present invention, the different density portions are recessed with respect to the first and second magnetized portions on the side opposite to the stator side along the radial direction of the rotor. ..

According to the rotary electric machine of the present invention, it has a first magnetized portion facing the first magnetic detector and a second magnetized portion facing the second magnetic detector, and magnetic poles of the first and second magnetized portions. In a two-stage magnet in which the two magnets are different from each other, a magnetic force weaker than the magnetic force of the first and second magnetized portions between the first magnetized portion and the second magnetized portion along the axial direction of the rotor of the two-stage magnet. A different density portion having or having no magnetic force is provided.

As a result, when the first magnetized portion and the second magnetized portion are magnetized to different poles from each other, one side and the other side of the two-stage magnet along the axial direction of the rotor are set with the different density portion as the boundary portion. It is possible to clearly separate the magnetic poles with and. At this time, when the two-stage magnet is magnetized in two stages, the magnetism of the different density portion is suppressed or not magnetized. Therefore, the magnetic poles of the magnets arranged on both sides of the two-stage magnet along the rotation direction of the rotor. It is suppressed to be affected by. That is, it is possible to suppress the occurrence of so-called "magnetized droop" (see FIG. 8) that obscures the boundary between different poles, and to clarify the boundary between different poles with one magnet. It is possible to suppress the variation and operate it with high accuracy.

Further, according to the method for manufacturing a rotor of the present invention, a two-stage magnet material having no magnetic force and a standard magnet material are prepared, and these magnet materials are arranged and fixed to the rotor, and then the rotor is subjected to a magnetizing step. Since it is completed, it is possible to facilitate the rotor assembly work while facilitating the parts management before assembly as compared with the case where the two-stage magnet and the standard magnet having magnetic force are fixed to the rotor in advance.

It is a perspective view which shows the rotary electric machine which concerns on this invention. It is explanatory drawing explaining the number of slots and the number of poles. It is a partial cross-sectional view of the rotary electric machine of FIG. 1 as seen from the side. It is a partial cross-sectional view which enlarged the part of the sensor unit of FIG. It is explanatory drawing explaining the shape and arrangement relation of a magnet. (A) and (b) are diagrams for explaining the details of the two-stage magnet. (A), (b), and (c) are explanatory views for explaining the manufacturing procedure of the rotor. It is a figure corresponding to FIG. 5 explaining the magnetizing state of the rotor of the comparative example. It is a perspective view which shows the two-stage magnet of Embodiment 2.

Hereinafter, Embodiment 1 of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a perspective view showing a rotating electric machine according to the present invention, FIG. 2 is an explanatory view for explaining the number of slots and the number of poles, and FIG. 3 is a partial cross-sectional view of the rotating electric machine of FIG. 1 as viewed from the side. 4 is an enlarged partial cross-sectional view of the sensor unit in FIG. 3, FIG. 5 is an explanatory view explaining the shape and arrangement of magnets, and FIGS. 6 (a) and 6 (b) are detailed structures of a two-stage magnet. 7 (a), (b), and (c) are explanatory views for explaining the rotor manufacturing procedure, and FIG. 8 is a view corresponding to FIG. 5 for explaining the magnetized state of the rotor of the comparative example. Are shown respectively.

The rotary electric machine 10 shown in FIGS. 1 to 3 is a so-called ACG starter, which is used for a starter and a generator of a motorcycle or the like (not shown). Specifically, the rotary electric machine 10 adopts the same structure as the outer rotor type brushless motor. Then, when the engine (not shown) is started, it operates as a starter motor by supplying a drive current from an in-vehicle battery (not shown), and after the engine is started, it operates as a generator by the driving force of the engine. ..

The rotary electric machine 10 is formed in a substantially flat disk shape as a whole, and is arranged at an axial end portion of a crankshaft (not shown) forming an engine. Specifically, the rotary electric machine 10 includes a stator 20 fixed inside a crankcase (not shown) and a rotor 30 fixed to the crankshaft and rotating with respect to the stator 20. As a result, the crankshaft is rotated by supplying the drive current to the rotary electric machine 10, and conversely, the rotor 30 is rotated by the rotation of the crankshaft.

The stator 20 includes a stator core 21 formed by laminating a plurality of steel plates (magnetic materials). The stator core 21 includes a main body portion 21a formed in a substantially cylindrical shape, and a plurality of teeth 21b protruding radially from the main body portion 21a. Specifically, a total of 18 teeth 21b are provided, and the base end portion thereof is integrated with the main body portion 21a. In other words, the stator core 21 is provided with a total of 18 slots SL (see FIG. 2).

An insulator 21c made of an insulator such as plastic is attached to each of the 18 teeth 21b in total. The insulator 21c is also provided on the outer peripheral portion of the main body portion 21a of the stator core 21. A U-phase coil Cu corresponding to the U-phase, a V-phase coil Cv corresponding to the V-phase, and a W-phase coil Cw corresponding to the W-phase are wound around the insulator 21c covering the teeth 21b by concentrated winding. It is dressed up.

Here, in FIG. 1, in order to make it easy to understand the wound state of each coil Cu, Cv, Cw, each coil Cu, Cv, Cw is shaded. The winding order of the U-phase coil Cu, the V-phase coil Cv, and the W-phase coil Cw is such that the U-phase coil Cu, the V-phase coil Cv, the W-phase coil Cw, and the U-phase coil Cu, with respect to the rotation direction of the rotor 30. V-phase coils Cv ... Alternate one phase at a time (see FIG. 2).

A sensor unit 22 is provided on the outer side of the stator core 21 in the radial direction and in a part along the circumferential direction. That is, the sensor unit 22 is fixed to the non-rotating portion of the rotary electric machine 10. The sensor unit 22 includes a housing 23 formed in a substantially T shape by an insulator such as plastic. The housing 23 includes a fixing portion 23a fixed to the stator core 21 and a sensor accommodating portion 23b accommodating a total of three sensor substrates 24u, 24v, 24w corresponding to the U phase, the V phase, and the W phase. There is. Here, the sensor accommodating portion 23b is arranged so as to extend outward in the radial direction of the stator core 21 and in the circumferential direction of the stator core 21, and is formed in a substantially arc shape.

As shown in FIG. 3, the U-phase sensor Su, the V-phase sensor Sv, and the W-phase sensor Sw are mounted on the sensor substrates 24u, 24v, and 24w housed in the sensor housing portion 23b of the housing 23, respectively. ing. Further, a rotation sensor Sr for detecting the ignition timing and the fuel injection timing is also mounted on the sensor substrate 24w corresponding to the W phase. Here, the U-phase, V-phase, and W-phase sensors Su, Sv, and Sw are arranged side by side in the rotation direction of the rotor 30 to form the first magnetic detector in the present invention. Further, one of the rotation sensors Sr constitutes the second magnetic detector in the present invention.

The four sensors Su, Sv, Sw, and Sr are Hall elements having the same configuration. Specifically, it is an alternating detection type (bipolar) Hall element that is switched on / off by a magnetic pole (N pole / S pole). For example, when the north pole is detected, an "on signal (1)" is generated, and when the south pole is detected, an "off signal (0)" is generated.

As a result, each sensor Su, Sv, Sw, Sr outputs a square wave signal (not shown) as the rotor 30 having a total of 12 magnets MG (see FIG. 5) rotates. ing. Therefore, the in-vehicle controller (not shown) grasps the rotational state of the rotor 30 based on the input of these rectangular wave signals, and supplies the drive current to each coil Cu, Cv, Cw at the optimum timing. can do. In addition, the in-vehicle controller can grasp the ignition timing and the fuel injection timing to control the igniter and the fuel pump (not shown).

As shown in FIGS. 3 and 4, the U-phase sensor Su, the V-phase sensor Sv, the W-phase sensor Sw, and the rotation sensor Sr are connected to the stator core 21 via the sensor substrates 24u, 24v, and 24w, respectively. It is in the space between the teeth 21b (the part of the slot SL). Here, the W-phase sensor Sw and the rotation sensor Sr are inserted in the same portion (the portion of the same slot SL) between the teeth 21b. The distance L between the W-phase sensor Sw and the rotation sensor Sr along the axial direction of the stator core 21 is set to about 5.0 mm.

More specifically, the U-phase, V-phase, and W-phase sensors Su, Sv, and Sw used for driving the rotary electric machine 10 are arranged substantially at the center along the axial direction of the stator core 21. On the other hand, the rotation sensor Sr used for detecting the ignition timing and the fuel injection timing is opposite to the boss portion 32 side along the axial direction of the stator core 21 for each of the driving sensors Su, Sv, Sw. It is arranged on the side (upper side in FIGS. 3 and 4).

In this way, a total of four sensors Su, Sv, Sw, and Sr are all provided on the stator core 21, and only one of the rotation sensors Sr is a rotor for each of the driving sensors Su, Sv, Sw. It is arranged so as to be offset in the axial direction of 30. Here, each of the sensors Su, Sv, Sw, and Sr is adapted to face a total of 12 magnets MG (see FIG. 5) from the inside in the radial direction of the rotary electric machine 10. As a result, each of the sensors Su, Sv, Sw, and Sr outputs a square wave signal due to a change in the magnetic poles (N pole / S pole) accompanying the rotation of the rotor 30.

Here, as shown in FIG. 5, each sensor Su, Sv, Sw, Sr moves (relatively rotates) relative to a total of 12 magnets MG, and the edge portions PN, PS of each magnet MG. Each magnetic pole is detected when approaching. For example, each sensor Su, Sv, Sw, Sr generates an "on signal (1)" when approaching the edge portion PN of the N pole, and "off signal (0)" when approaching the edge portion PS of the S pole. Is to be generated.

Here, 11 of the 12 magnets MG in total are standard magnets 33 having only one magnetic pole on the facing portion SF facing the stator core 21 (each sensor Su, Sv, Sw, Sr). On the other hand, the other one of the total of 12 magnets MG is a two-stage magnet 34 having two magnetic poles on the facing portion SF facing the stator core 21 (each sensor Su, Sv, Sw, Sr). ing.

The three U-phase sensors Su, the V-phase sensor Sv, and the W-phase sensor Sw are respectively opposed to the first magnetizing portion 34b (S pole) of the two-stage magnet 34, and one of them. The rotation sensor Sr faces the second magnetizing portion 34c (N pole) of the two-stage magnet 34. Here, in FIG. 4, each sensor Su, Sv, Sw, Sr is shaded in order to make it easy to understand the arrangement relationship of each sensor Su, Sv, Sw, Sr.

As shown in FIGS. 1 to 5, the rotor 30 includes a rotor main body 31. The rotor body 31 is formed into a substantially bowl shape by pressing a relatively thick steel plate (magnetic material), and has a substantially disk-shaped bottom wall portion 31a and an outer circumference of the bottom wall portion 31a. It is provided with a tubular side wall portion 31b that rises vertically from the portion.

Further, at the center of rotation of the bottom wall portion 31a, a cylindrical boss portion 32 to which the axial end portion of the crankshaft is fixed is fixed. As a result, the crankshaft is rotated as the rotor body 31 rotates. Here, the wall thickness of the boss portion 32 is thicker than the wall thickness of the rotor main body 31, whereby the fixing strength between the rotary electric machine 10 and the engine (crankshaft) is sufficiently secured. Therefore, the occurrence of uneven rotation during high-speed rotation or the like can be suppressed, and the load applied to both the engine (crankshaft) and the rotary electric machine 10 can be reduced.

A total of 12 magnets MG are mounted on the radial inside of the cylindrical side wall portion 31b, that is, on the stator core 21 side of the side wall portion 31b. These magnets MG are ferrite magnets, which are made by adding a small amount of barium, strontium, etc. to iron oxide as a main raw material and baking them. As shown in the shaded portion of FIG. 2, the magnet MG is formed in a substantially arc shape following the shape of the cylindrical side wall portion 31b (see FIG. 1). These magnets MG are fixed to the side wall portion 31b with an adhesive or the like (not shown).

Further, a total of 12 magnets MG are pressed from the radial inside of the rotor main body 31 toward the side wall portion 31b by the magnet holder HD formed in a substantially cylindrical shape. As a result, each magnet MG is prevented from falling off from the side wall portion 31b. Here, the magnet holder HD is formed of a thin stainless steel plate or the like having flexibility, and also has a function of positioning each magnet MG at equal intervals in the circumferential direction of the side wall portion 31b. This facilitates the fixing work of each magnet MG to the side wall portion 31b and improves the assembling workability of the rotary electric machine 10.

The positional relationship between the total of 12 magnets MG and the total of 4 sensors Su, Sv, Sw, Sr is the positional relationship shown in FIG. FIG. 5 is a schematic view of the cylindrical side wall portion 31b (see FIG. 3) of the rotor main body 31 developed in a plane.

The width dimension W of each magnet MG is set to about 30 mm, and the height dimension H of each magnet MG is set to about 20 mm. Further, the interval dimension G of each magnet MG along the rotation direction of the rotor 30 is set to about 2 mm. The pitch P1 of the edge portions PN and PS of each magnet MG is set to 30 degrees. This pitch P1 (30 degrees) coincides with the arrangement interval of each magnet MG along the rotation direction of the rotor 30, and is obtained based on "360 degrees ÷ 12 poles".

On the other hand, the pitch P2 of each of the driving sensors Su, Sv, and Sw is set to 20 degrees. This pitch P2 (20 degrees) coincides with the arrangement interval of each slot SL (see FIG. 2) along the rotation direction of the rotor 30, and is obtained based on “360 degrees ÷ 18 slots”. As described above, the rotary electric machine 10 in the present embodiment forms a brushless motor having [12 poles and 18 slots]. This enables smooth rotary drive in which the generation of cogging torque is suppressed.

As shown in FIG. 5, a total of 11 standard magnets 33 are formed in a simple rectangular shape having no concave grooves or the like (different density portions or the like) in a flatly developed state. The magnetic poles of the opposing portions SF are arranged so that different poles appear alternately in the north pole, the south pole, the north pole, the south pole, etc. with respect to the rotation direction of the rotor 30 (the left-right direction in the drawing). Here, in FIGS. 5 and 6 (b), the thin shaded portion is the south pole and the dark shaded portion is the north pole.

On the other hand, the other two-stage magnet 34 is a deformed magnet having a concave groove 34a on the opposite portion SF side as shown in FIGS. 5 and 6, and is bounded by the concave groove 34a. A first magnetized portion 34b occupying a large surface area and a second magnetized portion 34c having a surface area smaller than the surface area of the first magnetized portion 34b are provided. The two-stage magnet 34 is arranged between the standard magnets 33 in which the opposing portion SF is magnetized to one pole of the N pole, the first magnetized portion 34b is magnetized to the S pole, and the second magnet is attached. The magnetic portion 34c is magnetized to the north pole. That is, the magnetic poles of the first magnetized portion 34b and the magnetic poles of the second magnetized portion 34c are different from each other.

Further, the portion of the two-stage magnet 34 provided with the concave groove 34a is thinner than the portions of the first magnetizing portion 34b and the second magnetizing portion 34c of the two-stage magnet 34 (FIG. 6 (FIG. 6). b) See). This thinned portion is a different density portion 34d having a magnetic force weaker than the magnetic force of the first and second magnetizing portions 34b and 34c. Specifically, as shown in FIG. 6B, the magnetic poles on the concave groove 34a side (right side in the drawing) of the different density portion 34d are the same magnetic poles as the second magnetized portion 34c (however, the different density portion 34d). Is a little less than N).

The different density portion 34d is provided between the first magnetizing portion 34b and the second magnetizing portion 34c along the axial direction of the rotor 30 (vertical direction in FIG. 6), and the first and second magnetizing portions 34d are provided. The portions 34b and 34c are recessed on the side opposite to the stator 20 side (left side in FIG. 6B) along the radial direction of the rotor 30. Then, as shown in FIG. 6B, the wall thickness dimension t1 of the different density portion 34d is substantially half of the wall thickness dimension t2 of the first and second magnetized portions 34b and 34c (t1≈ t2 / 2).

The second magnetized portion 34c of the two-stage magnet 34 is much smaller than the first magnetized portion 34b, and as shown in FIG. 5, the thickness dimension w1 of the second magnetized portion 34c is about 2 mm. It has become. That is, the thickness dimension w1 of the second magnetized portion 34c is about one tenth of the height dimension H (about 20 mm) of the two-stage magnet 34. In other words, the axial length dimension (about 17 mm) of the rotor 30 of the first magnetized portion 34b is much larger than the axial length dimension (about 2 mm) of the rotor 30 of the second magnetized portion 34c. It's getting bigger.

Further, the thickness dimension w2 of the different density portion 34d (concave groove 34a) is about 1 mm, which is approximately half of the thickness dimension w1 (about 2 mm) of the second magnetized portion 34c (w2≈w1 / 2). ). Both the second magnetized portion 34c and the different density portion 34d (recessed groove 34a) extend in a band shape in the rotation direction of the rotor 30.

Here, the portion between the first magnetized portion 34b and the second magnetized portion 34c and closer to the first magnetized portion 34b of the different density portion 34d is a boundary portion BL indicating the boundary of the magnetic poles. .. Specifically, the boundary portion BL provided on the opposite portion SF of the two-stage magnet 34 is the boundary between the S pole of the first magnetized portion 34b and the north pole of the second magnetized portion 34c and the different density portion 34d. It is a line. That is, the north pole (weak) of the different density portion 34d and the south pole of the first magnetizing portion 34b do not straddle the boundary portion BL with each other.

Further, as shown in FIG. 5, a detection boundary line LN is formed in the vicinity of the boundary portion BL as shown by a virtual line (dashed-dotted line). The detection boundary line LN is slightly offset toward the first magnetizing portion 34b with respect to the boundary portion BL, and is arranged exactly in the center between the W phase sensor Sw and the rotation sensor Sr. The first magnetized portion 34b side (lower side in the figure) of the detection boundary line LN is the first detection region AR1 in which the driving sensors Su, Sv, and Sw can detect changes in the magnetic poles. The second magnetized portion 34c side (upper side in the drawing) of the detection boundary line LN is the second detection region AR2 in which the rotation sensor Sr can detect the change of the magnetic pole.

Here, in order to improve the detection accuracy of each of the driving sensors Su, Sv, Sw and the detection accuracy of the rotation sensor Sr, the position of the detection boundary line LN and the position of the boundary portion BL with respect to the axial direction of the rotor 30 It is desirable to make a perfect match. By doing so, it is possible to accurately detect each magnetic pole without being affected by the other magnetic pole. However, in reality, it is difficult to completely match the position of the detection boundary line LN with the position of the boundary portion BL because the dimensional accuracy of the component parts varies and the rotor 30 is misaligned with respect to the stator 20. be.

Therefore, in design, the first sensors Su, Sv, and Sw for driving are placed on the different density portion 34d side with the detection boundary line LN as the center so that the change of the magnetic pole can be detected with higher accuracy. The S pole of the magnetic portion 34b is slightly protruded. As a result, the detection accuracy of each of the driving sensors Su, Sv, and Sw is sufficiently ensured, and the rotary electric machine 10 can be reliably driven as a starter motor.

Here, as shown in FIG. 5, the pitch P2 of each of the driving sensors Su, Sv, and Sw is 20 degrees. Therefore, the driving sensors Su, Sv, and Sw do not face one magnet MG at the same time. Then, each of the driving sensors Su, Sv, and Sw outputs a rectangular wave signal at different timings, so that the in-vehicle controller grasps the rotation state (rotation direction, rotation speed, etc.) of the rotor 30. There is.

Here, the rotation sensor Sr faces the north pole three times in a row at the portion of the two-stage magnet 34 while the rotor 30 makes one rotation. That is, when the length of the rectangular wave signal output by each of the driving sensors Su, Sv, Sw is "1", the length of each of the driving sensors Su, Sv, Sw is always "1". Outputs a square wave signal. On the other hand, the rotation sensor Sr outputs a square wave signal having a length of "3" when facing the N pole three times in a row. Therefore, the in-vehicle controller can grasp that the rotor 30 has made one rotation based on the input of the long rectangular wave signal from the rotation sensor Sr.

In this way, the rotary electric machine 10 according to the present embodiment can be efficiently rotationally driven as a starter motor, and the ignition timing and the fuel injection timing can be reliably detected.

As shown in FIG. 5, the rotation sensor Sr is moved from the second magnetized portion 34c magnetized to the north pole to the side opposite to the first magnetized portion 34b side with respect to the axial direction of the rotor 30. It is placed in a position that slightly protrudes. As a result, the rotation sensor Sr is less likely to be affected by the S pole of the first magnetized portion 34b slightly protruding toward the second magnetized portion 34c with the detection boundary line LN as the center. Therefore, the detection accuracy of the rotation sensor Sr does not decrease.

Next, a manufacturing method (assembly procedure) of the rotor 30 provided with a total of 12 magnets MG (11 standard magnets 33 and 1 two-stage magnet 34) will be described in detail with reference to the drawings.

[Magnet material preparation process]
First, as shown in FIG. 7A, one (one) two-stage magnet material W1 serving as a two-stage magnet 34 and a plurality (11) standard magnet materials W2 serving as a standard magnet 33 are formed. prepare. This completes the [Magnet material preparation process].

Here, each of the magnet materials W1 and W2 is a sintered product, and by performing sintering molding using a mold having a specific shape, the shape as shown in FIG. 7A is obtained. However, in the two-stage magnet material W1, the concave groove 34a may be formed as shown in FIG. 6 by performing cutting or the like on the standard magnet material W2 after sintering and molding.

Further, the two-stage magnet material W1 and the standard magnet material W2 are materials in a state where magnetization work has not been performed, that is, materials having no magnetic force. Therefore, the individual parts do not stick to each other by magnetic force. Therefore, it is possible to facilitate the management of these parts and improve the workability of assembling to the rotor main body 31 (see FIG. 3).

In FIG. 7, only the two-stage magnet material W1 (two-stage magnet 34) and the pair of standard magnet materials W2 (standard magnet 33) arranged on both sides of the two-stage magnet material W1 (two-stage magnet 34) are arranged so that the state of the magnetizing work can be easily understood. Is shown.

[Magnet material fixing process]
Next, one two-stage magnet material W1 and 11 standard magnet materials W2 prepared in the [Magnet material preparation step] are placed around the side wall portion 31b (see FIG. 3) of the rotor main body 31 in the radial direction. Perform the work of arranging and fixing in the direction. At this time, a predetermined amount of adhesive (not shown) is applied to the inside of the side wall portion 31b in the radial direction, and a total of 12 magnets are used using a magnet holder HD (see FIG. 3) before the adhesive dries. The materials W1 and W2 are positioned in close contact with the side wall portion 31b.

As a result, the magnet materials W1 and W2 are arranged and fixed in the circumferential direction of the rotor body 31 with an interval dimension G (about 2 mm) (see FIGS. 3 and 5). This completes the [Magnet material fixing process]. Here, in order to dry the adhesive quickly and surely, the rotor main body 31 to which the magnet materials W1 and W2 are fixed may be put into a drying furnace (not shown). At this time, since the magnet materials W1 and W2 are in the state before magnetism, problems such as thermal demagnetization do not occur.

[Primary magnetizing process]
Next, as shown in FIG. 7A, the first magnetizing operation is performed on the magnet materials W1 and W2 so that the north and south poles appear alternately in the rotation direction of the rotor 30. At this time, a first magnetizing device MM1 (not shown in detail) capable of magnetizing the magnet materials W1 and W2 individually and at once is set inside the side wall portion 31b of the rotor main body 31 in the radial direction. More specifically, the first magnetizing device MM1 is set in the portion SF facing the stator 20 in each of the magnet materials W1 and W2, and each magnetizing coil MC1 provided in the first magnetizing device MM1 is set. The magnet materials W1 and W2 face the front surface of the SF facing the stator 20.

After that, the first magnetizing device MM1 is driven to pass a current of a predetermined magnitude through each magnetizing coil MC1. At this time, as shown in FIG. 7A, the direction of the current flowing through each magnetizing coil MC1 is changed. Then, as shown in the shaded portion of FIG. 7B, the entire surface of the facing portion SF in the two-stage magnet material W1 is magnetized to the S pole, and the entire surface of the facing portion SF in the standard magnet material W2 on both sides thereof is magnetized. Each is magnetized to the N pole. As a result, the [primary magnetizing step] is completed.

[Secondary magnetizing process]
Next, as shown in FIG. 7B, a second magnetizing operation is performed in which only the two-stage magnet material W1 is magnetized again. At this time, a second magnetizing device MM2 different from the first magnetizing device MM1 used in the above-mentioned [primary magnetizing step] is used. Specifically, the second magnetizing device MM2 includes one two-stage magnetizing coil MC2. The two-stage magnetizing coil MC2 magnetizes the facing portion SF of the two-stage magnet material W1 to the S pole portion having a large surface area and the N pole portion having a small surface area. That is, the two-stage magnetizing coil MC2 includes a large S-pole coil MS and a small N-pole coil MN.

Then, the two-stage magnetizing coil MC2 is made to face the front surface of the facing portion SF of the two-stage magnet material W1 with the stator 20. As a result, the S-pole coil MS faces the first magnetizing portion 34b of the two-stage magnet material W1, and the N-pole coil MN faces the second magnetizing portion 34c of the two-stage magnet material W1.

Next, the second magnetizing device MM2 is driven to pass a current of a predetermined magnitude through the S-pole coil MS and the N-pole coil MN of the two-stage magnetizing coil MC2. At this time, as shown in FIG. 7B, the directions of the currents flowing through the S-pole coil MS and the N-pole coil MN are opposite to each other.

As a result, as shown in the shaded portion of FIG. 7C, the first magnetized portion 34b has a portion where the different density portion 34d (recessed groove 34a) of the two-stage magnet material W1 is provided as the boundary portion BL. It is magnetized to the S pole (one magnetic pole), and the second magnetized portion 34c is magnetized to the N pole (the other magnetic pole). As a result, the [secondary magnetizing step] is completed, the two-stage magnet material W1 is magnetized in two stages, and the two-stage magnet 34 is completed. At this time, the different density portion 34d of the concave groove 34a portion is magnetized to the north pole (weak). This is because the different density portion 34d is separated from the N-pole coil MN. As a result, all the magnetizing steps are completed, and the rotor 30 is completed.

Here, the above-mentioned [primary magnetizing step] and [secondary magnetizing step] constitute the magnetizing step of the present invention.

Further, the S-pole coil MS and the N-pole coil MN magnetize opposite poles to each other with the boundary portion BL as a boundary. Therefore, it is possible to clearly separate the S pole and the N pole with the boundary portion BL as a boundary. Further, since the two-stage magnet material W1 is provided with the concave groove 34a (different density portion 34d), the occurrence of so-called "magnetism dripping" in the [secondary magnetizing step] is suppressed. When the "magnetized drool" occurs, the detection accuracy of each of the driving sensors Su, Sv, and Sw (see FIG. 5) is lowered.

Hereinafter, the mechanism of generating the so-called “magnetized droop” that reduces the detection accuracy of each of the driving sensors Su, Sv, and Sw will be described in detail with reference to the drawings.

Here, as shown in FIG. 8, a rotor having a two-stage magnet A (comparative example) formed in a simple rectangular shape without any concave groove or the like will be described as a model. In this comparative example, while preparing three standard magnet materials B having the same shape, only the standard magnet material B in the middle is subjected to exactly the same steps as the above-mentioned [primary magnetizing step] and [secondary magnetizing step]. Use a two-stage magnet A.

In this case, so-called "magnetizing drips" are generated on both sides of the two-stage magnet A along the rotation direction of the rotor. As shown by the broken line circle in FIG. 8, the “magnetized spill” referred to here means that the N poles on both sides of the second magnetized portion 34c along the rotation direction of the rotor cross the detection boundary line LN. This is a phenomenon in which the magnetized portion 34b protrudes to the side. This is because the opposing portion SFs arranged on both sides of the two-stage magnet A are affected by the magnetic force of the standard magnet C magnetized on the N pole. Therefore, in order to prevent the occurrence of this "magnetized drool", in the present embodiment, a concave groove 34a (see FIG. 6) is provided in advance at a place where the "magnetized drool" can occur.

Then, the "space" forming the concave groove 34a functions so as to block the transmission of the magnetic force of the standard magnet C, whereby, as shown in FIG. 7 (c), the opposing portions of the standard magnets 33 on both sides. It does not have to be affected by the north pole of SF. At that time, since the thin-walled different density portion 34d is separated from the N-pole coil MN via the concave groove 34a, it is magnetized to the weak N-pole. In any case, it is possible to clearly separate the first magnetizing portion 34b into the S pole and the second magnetizing portion 34c into the N pole with the boundary portion BL as a boundary.

As described in detail above, according to the rotary electric machine 10 according to the present embodiment, the first magnetizing portion 34b and the rotation sensor Sr facing the U-phase, V-phase, and W-phase sensors Su, Sv, and Sw. In a two-stage magnet 34 having a second magnetized portion 34c facing the magnet and having magnetic poles of the first and second magnetized portions 34b and 34c different from each other, a second magnet 34 along the axial direction of the rotor 30 of the two-stage magnet 34. Between the first magnetized portion 34b and the second magnetized portion 34c, a different density portion 34d having a magnetic force (N weak) weaker than the magnetic force of the first and second magnetized portions 34b and 34c is provided.

As a result, when the first magnetizing portion 34b and the second magnetizing portion 34c are magnetized to different poles from each other, the two-stage magnet 34 along the axial direction of the rotor 30 is set with the portion of the different density portion 34d as the boundary portion BL. It is possible to clearly separate the magnetic poles on one side and the other side. At this time, when the two-stage magnet 34 is magnetized in two stages, the magnetism of the different density portion 34d is suppressed, so that the standard magnets 33 arranged on both sides of the two-stage magnet 34 along the rotation direction of the rotor 30 It is suppressed from being affected by the magnetic poles. That is, the occurrence of so-called "magnetized droop" (see FIG. 8) that obscures the boundary BL between different poles can be suppressed, and the boundary BL between different poles can be made clear in one magnet MG, which in turn is a product. It is possible to suppress the variation in characteristics for each case and to operate with high accuracy.

Further, according to the rotary electric machine 10 according to the present embodiment, the length dimension of the first magnetizing portion 34b with respect to the axial direction of the rotor 30 is larger than the length dimension of the second magnetizing portion 34c with respect to the axial direction. Therefore, it is possible to sufficiently secure the detection accuracy of each of the driving sensors Su, Sv, and Sw, which needs to detect the change of the magnetic pole more accurately. Therefore, the rotary electric machine 10 can be reliably driven as a starter motor.

Further, according to the rotary electric machine 10 according to the present embodiment, the different density portions 34d are on the side opposite to the stator 20 side along the radial direction of the rotor 30 with respect to the first and second magnetizing portions 34b and 34c. Since it is recessed in, it can be separated from the N-pole coil MN of the two-stage magnetizing coil MC2 in the above-mentioned [secondary magnetizing step]. Therefore, the different density portion 34d can be magnetized to a weak N pole (N weak), and thus the occurrence of "magnetized drool" can be reliably suppressed, and the boundary portion BL between different poles can be made clearer.

Further, according to the method for manufacturing the rotor 30 according to the present embodiment, a two-stage magnet material W1 and a standard magnet material W2 having no magnetic force are prepared, and these magnet materials W1 and W2 are arranged side by side and fixed to the rotor 30. Later, the rotor 30 is completed through the [primary magnetizing step] and the [secondary magnetizing step], so that the two-stage magnet having magnetic force and the standard magnet are assembled as compared with the case where they are fixed to the rotor in advance. It is possible to facilitate the rotor assembly work while facilitating the previous parts management.

Next, Embodiment 2 of the present invention will be described in detail with reference to the drawings. FIG. 9 shows a perspective view showing the two-stage magnet of the second embodiment.

The two-stage magnet 40 of the second embodiment is magnetized as shown in the shaded portion of FIG. 9 by magnetizing the plastic magnet material W3 formed in three colors by extrusion molding. Specifically, by going through exactly the same steps as the above-mentioned [primary magnetizing step] and [secondary magnetizing step], the plastic magnet material W3 becomes a two-stage magnet 40. Also in the two-stage magnet 40 of the second embodiment, standard magnets 33 (see FIG. 5) are arranged on both sides of the two-stage magnet 40.

The two-stage magnet 40 is formed in a flexible sheet shape (flat plate shape), and has a first magnetized portion 41 that occupies a large surface area and a surface area smaller than the surface area of the first magnetized portion 41. It includes two magnetizing portions 42. The first magnetizing portion 41 faces each of the driving sensors Su, Sv, Sw (see FIG. 5), and the second magnetizing portion 42 faces the rotation sensor Sr (see FIG. 5). The first magnetized portion 41 on the opposing portion SF is magnetized to the S pole, the second magnetized portion 42 on the opposing portion SF is magnetized to the N pole, and the magnetic pole of the first magnetized portion 41. And the magnetic poles of the second magnetized portion 42 are different from each other.

Further, between the first magnetizing portion 41 and the second magnetizing portion 42 along the axial direction (vertical direction in the drawing) of the rotor 30 of the two-stage magnet 40, the first and second magnetizing portions 41 and 42 Is provided with a different density portion 43 (without shading) which has a magnetic force but does not have a magnetic force. The portion of the different density portion 43 is formed of a plastic material (non-magnetic material) that does not contain a magnetic material, and is not magnetized during the magnetizing treatment.

The dimensional relationship between the first magnetized portion 41, the second magnetized portion 42, and the different density portion 43 along the axial and circumferential directions of the rotor 30 is the same as that of the two-stage magnet 34 (see FIG. 5) of the first embodiment. It is almost the same. However, since the two-stage magnet 40 has a sheet shape, its wall thickness dimension t3 is thinner than the wall thickness dimension t2 (see FIG. 6B) of the two-stage magnet 34 of the first embodiment. (T3 <t2).

Here, the first magnetizing portion 41 and the second magnetizing portion 42 are both formed of a plastic material (the same material) containing the same amount of magnetic material, and both can be magnetized to a magnetic force of substantially the same magnitude. It has become. Since the magnetic force of the different density portion 43 may be weaker than the magnetic force of the first and second magnetizing portions 41 and 42, the different density portion 43 may be formed of a plastic material (weak magnetic material) containing a small amount of a magnetic material. can.

Even in such a second embodiment, the same effect as that of the first embodiment described above can be obtained. In addition to this, in the second embodiment, since the two-stage magnet 40 is composed of a flexible "plastic magnet", it can be cut to an arbitrary length after extrusion molding according to a required size. .. Therefore, the two-stage magnet 40 can be easily manufactured. Further, since the two-stage magnet 40 is deformable, it is possible to easily cope with variations of a plurality of rotors (large-diameter rotor, small-diameter rotor, etc.) on which the two-stage magnet 40 is mounted.

It goes without saying that the present invention is not limited to each of the above embodiments, and various modifications can be made without departing from the gist thereof. For example, in each of the above embodiments, as shown in FIG. 7, in the magnetizing step, the first magnetizing device MM1 is used [primary magnetizing step] and the second magnetizing device MM2 is used [. The secondary magnetizing step] has been shown individually in this order, but the present invention is not limited to this. For example, by using one magnetizing device (not shown) provided with a plurality of magnetizing coils MC1 and one two-stage magnetizing coil MC2, a single magnetizing operation can be shown in FIG. 7 (c) at once. It can also be in the magnetized state (completed) as shown. In this case, the time required for the magnetizing process can be halved, and the manufacturing cost can be reduced.

Further, in each of the above embodiments, the rotary electric machine 10 has a brushless motor structure of "12 poles and 18 slots", but the present invention is not limited to this, and the number of other poles and the number of other slots are not limited to this. It doesn't matter.

Further, in each of the above embodiments, the rotary electric machine 10 is used as a starter for a motorcycle or the like and an ACG starter used for a generator, but the present invention is not limited to this, and for example, agricultural machinery such as a cultivator. It can also be applied to an ACG starter (rotary electric machine) used for starting an engine of an outboard motor of a small vessel or a small vessel.

In addition, the material, shape, dimensions, number, installation location, etc. of each component in each of the above embodiments are arbitrary as long as the present invention can be achieved, and are not limited to the above embodiments.

10 Rotating electric machine 20 Stator 21 Stator core 21a Main body 21b Teeth 21c Insulator 22 Sensor unit 23 Housing 23a Fixed part 23b Sensor housing part 24u, 24v, 24w Sensor board 30 Rotor 31 Rotor body 31a Bottom wall part 31b Side wall part 32 Boss part 33 Standard Magnet (magnet)
34 Two-stage magnet (magnet)
34a Concave groove 34b 1st magnetizing part 34c 2nd magnetizing part 34d Different density part 40 2nd stage magnet 41 1st magnetizing part 42 2nd magnetizing part 43 Different density part A 2nd stage magnet AR1 1st detection area AR2 No. 2 Detection area B Standard magnet material BL Boundary C Standard magnet Cu U-phase coil (coil)
Cv V phase coil (coil)
Cw W phase coil (coil)
HD magnet holder LN detection boundary line MC1 magnetizing coil MC2 two-stage magnetizing coil MG magnet MM1 first magnetizing device (magnetizing device)
MM2 2nd magnetizing device (magnetizing device)
MN N-pole coil MS S-pole coil PN, PS Edge part SF Opposing part SL slot Sr Rotation sensor (second magnetic detector part)
Su U phase sensor (first magnetic detector)
Sv V phase sensor (first magnetic detector)
Sw W phase sensor (1st magnetic detector)
W1 2-stage magnet material (magnet material)
W2 standard magnet material (magnet material)
W3 plastic magnet material (magnet material)

Claims (6)

A stator with multiple coils wound around it,
A rotor that rotates with respect to the stator,
It is a rotary electric machine equipped with
Three first magnetic detectors provided on the stator and arranged side by side in the rotation direction of the rotor,
A second magnetic detector provided on the stator and arranged so as to be displaced in the axial direction of the rotor with respect to the first magnetic detector.
A plurality of magnets provided on the rotor, facing the first and second magnetic detectors, and arranged so that N poles and S poles appear alternately in the rotation direction of the rotor.
Have,
One of the plurality of magnets has a first magnetized portion facing the first magnetic detector and a second magnetized portion facing the second magnetic detector, and the first and second magnets are attached. It is a two-stage magnet in which the magnetic poles of the magnetic part are different from each other.
Between the first magnetized portion and the second magnetized portion along the axial direction of the rotor of the two-stage magnet, there is a magnetic force weaker than the magnetic force of the first and second magnetized portions, or a magnetic force. It is characterized in that a different density part having no magnetism is provided.
Rotating electric machine. The length dimension of the first magnetized portion with respect to the axial direction of the rotor is larger than the length dimension of the second magnetized portion with respect to the axial direction of the rotor.
The rotary electric machine according to claim 1. The different density portion is recessed with respect to the first and second magnetized portions on the side opposite to the stator side along the radial direction of the rotor.
The rotary electric machine according to claim 1 or 2. A method of manufacturing a rotor that rotates with respect to a stator.
It has a first magnetized portion and a second magnetized portion that are magnetized to magnetic poles different from each other in the axial direction of the rotor, and the first magnetized portion and the second magnetized portion are said to have the same magnetism. One two-stage magnet material having a different density part that is magnetized or not magnetized by a magnetic force weaker than the first and second magnetizing parts, and a plurality of standard magnet materials that do not have the different density part. Magnet material preparation process to prepare and
A magnet material fixing step of arranging the two-stage magnet material and the standard magnet material in the circumferential direction of the rotor and fixing them to the rotor.
A magnetizing device is set on the two-stage magnet material fixed to the rotor and the portion of the standard magnet material facing the stator so that different poles appear alternately in the rotation direction of the rotor. The first magnetized portion that is magnetized and faces the first magnetic detector portion provided on the stator is attached to one magnetic pole with the portion of the two-stage magnet material provided with the different density portion as a boundary portion. A magnetizing step of magnetizing and magnetizing the second magnetized portion facing the second magnetic detector provided on the stator to another magnetic pole.
Characterized by having
How to manufacture the rotor. The length dimension of the first magnetized portion with respect to the axial direction of the rotor is larger than the length dimension of the second magnetized portion with respect to the axial direction of the rotor.
The method for manufacturing a rotor according to claim 4. The different density portion is recessed with respect to the first and second magnetized portions on the side opposite to the stator side along the radial direction of the rotor.
The method for manufacturing a rotor according to claim 4 or 5.

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