JP2014103750A - Rotary electric machine and battery charge control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotary electric machine in which electric loss can be reduced.SOLUTION: An outer rotor 36 is integrally attached and fixed to a left side shaft end of a crank shaft 19 and a coil stator 40 is arranged on the inner side thereof. The outer rotor 36 is molded with drawing in a cup shape using, for example, a stainless steel plate as material and a magnet 37 is arranged on an inner peripheral surface of a cylindrical part 36a thereof. A metal cover 38 for protecting the magnet 37 is mounted on the outer rotor 36 and a plurality of openings 39 for exposing the magnet 37 are formed on a cylindrical part 38a of the cover 38. By forming the openings 39 in the cover 38, portion through which a magnetic flux transmits in the cover 38 is reduced and the generation of an eddy current in the cover 38 is suppressed to reduce iron loss.

Description

  The present invention relates to a rotating electrical machine including a rotor having a magnet and a coil stator around which a plurality of coils are wound, and a battery charge control device.

  A vehicle such as a motorcycle is equipped with an AC generator, which is a rotating electrical machine driven by an engine (see, for example, Patent Document 1). The AC generator includes a rotor (rotor) having magnets and a coil stator (stator) around which a plurality of coils are wound, and generates power based on the principle of electromagnetic induction.

Japanese Patent No. 4299555

The electrical loss that occurs when the generator generates electricity is mainly the sum of the power generation output, iron loss, and copper loss. The power generation output is a loss due to the power generation output possessed by the generator. The iron loss is, for example, a loss due to eddy current generated in the stator and hysteresis loss. Copper loss is loss that occurs when a current flows through a coil wound around a stator.
From the viewpoint of increasing the power generation efficiency of the generator, it is required to reduce the electrical loss. For example, as a technique for reducing iron loss, a technique for suppressing the generation of eddy currents by using a silicon steel plate as a stator material, reducing the thickness of the laminated core of the stator, or reducing the thickness of one stator core sheet. It has been known.

  This invention is made | formed in view of the above points, and it aims at providing the rotary electric machine which can reduce an electrical loss.

A rotating electrical machine according to the present invention is a rotating electrical machine including a rotor having magnets and a coil stator around which a plurality of coils are wound, and the rotor is provided with a cover for protecting the magnets. The cover is made of metal, and an opening is formed so as to expose a part of the magnet, or the cover is made of resin.
Another feature of the rotating electrical machine of the present invention is that the rotor is an outer rotor, the magnet is disposed on an inner peripheral surface of a cylindrical portion thereof, the cover is made of metal, and the magnet A plurality of openings are formed along the cylindrical portion.
The battery charge control device of the present invention is an AC generator in which the rotating electrical machine of the present invention is driven by an engine, and is a battery charge control device for rectifying the output to charge the battery, and the battery voltage When the voltage reaches a predetermined voltage, the AC generator is disconnected from the battery.

  According to the present invention, it is possible to suppress the generation of eddy currents in the cover that is attached to the rotor and protects the magnet, so that it is possible to reduce electrical loss, particularly iron loss.

It is a left side view showing an example of a power unit mounted on a motorcycle. It is sectional drawing which passes along a crankshaft axis line and follows a cylinder axial direction. It is a perspective view which shows an outer rotor. It is a figure which shows the example of arrangement | positioning of a magnet. It is a figure for demonstrating a cover. It is a perspective view which shows a coil stator. It is a figure which shows the structure of the charge control apparatus of a short system battery. It is a figure which shows the structure of the charge control apparatus of an open system battery. It is a characteristic view which shows the relationship between an engine speed and an electrical loss.

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a left side view showing an example of a power unit 10 mounted on a motorcycle. In this example, the power unit 10 includes an air-cooled four-cycle single-cylinder engine 11. The engine 11 mainly includes a crankcase 12 that rotatably supports and accommodates a crankshaft, and a cylinder that is coupled to an end of the crankcase 12. Or the cylinder block 13 and the cylinder head 14 couple | bonded with the edge part of the cylinder 13 and the cylinder head cover 15 covered with the cylinder head 14 are comprised.

  The engine 11 will be further described. FIG. 2 shows a cross-sectional view along the cylinder axis direction through the crankshaft axis. In this example, the crankcase 12 is divided into left and right parts. In FIG. 2, the crankcase 12 includes a right crankcase 12R and a left crankcase 12L, which are paired on the left and right sides, and are coupled and integrated with each other, thereby forming a crank chamber 18. In the crank chamber 18, a crankshaft 19 and a pair of left and right crank webs 19 a integrated with the crankshaft 19 are rotatably supported via a pair of bearings 20.

  The base end side of the connecting rod 22 is connected between the crank webs 19a via the crank pins 21. A piston 23 is accommodated in the cylinder 13 so as to be able to reciprocate. The piston 23 is connected to the leading end side of the connecting rod 22 via a piston pin 24. As the piston 23 reciprocates in the cylinder axis direction, the crankshaft 19 rotates. Further, in the cylinder head 14, a valve operating device including a cam, a cam shaft and the like is incorporated. A cam timing chain 26 is wound between a sprocket attached to one end of each of the intake side and intake side camshafts and a drive sprocket 25 attached to the crankshaft, and moves in synchronization with the rotation of the crankshaft 19. The valve device is activated.

  Around the crank chamber 18, a clutch chamber 27 is disposed adjacent to the right side of the case partition wall, and a magnet chamber 28 is disposed adjacent to the left side. A clutch device 29 disposed at the right shaft end of the crankshaft 19 is accommodated in the clutch chamber 27, and the clutch chamber 27 is covered with a clutch cover 30. The magneto chamber 28 accommodates a magneto device 31 arranged and arranged at the left shaft end of the crankshaft 19, and the magneto chamber 28 is covered with a magneto cover 32 (crankcase cover).

In the magneto device 31, the outer rotor 36 is integrally attached and fixed to the left shaft end portion of the crankshaft 19. That is, the outer rotor 36 rotates integrally with the crankshaft 19. FIG. 3 shows the outer rotor 36. The outer rotor 36 is press-drawn into a cup shape using, for example, a stainless steel plate, and includes a cylindrical portion 36a and an annular wall portion 36b that is bent radially inward from one end of the cylindrical portion 36a. The left end portion of the crankshaft 19 is coupled to the center of 36b.
A magnet 37 is disposed on the inner peripheral surface of the cylindrical portion 36 a of the outer rotor 36. For example, as shown in FIG. 4, the magnet 37 divided into four is arranged along the inner peripheral surface of the cylindrical part 36a.

A metal cover 38 made of a thin plate is attached to the outer rotor 36 in order to protect the magnet 37. Examples of metal types include stainless steel plates and rolled steel plates. When the coil stator 40 attached to the magnet cover 32 is assembled to the outer rotor 36 attached and fixed to the left shaft end of the crankshaft 19, the coil stator 40 may be pulled by the magnetic force and hit the magnet 37. At this time, a cover 38 is provided for the purpose of preventing the magnet 37 from being caught or broken.
As shown also in FIG. 5, the cover 38 has a cylindrical portion 38 a that covers the magnet 37. The outer rotor 36 has an annular support wall 38b that is bent radially outward from the end of the cylindrical portion 38a on the opening side of the outer rotor 36, and the support wall 38b is fixed to the outer periphery of the outer rotor 36 by, for example, caulking. Is done. Further, on the wall 36b side of the outer rotor 36, there are a plurality of support wall portions 38c that are bent radially inward from the end of the cylindrical portion 38a, and these support wall portions 38c are fixed to the wall portion 36b of the outer rotor 36. The

  Here, a plurality of openings 39 are formed in the cylindrical portion 38a of the cover 38 along the cylindrical portion 38a. Each opening 39 is formed so as to penetrate the inner and outer peripheral surfaces of the cylindrical portion 38 a, and a part of the magnet 37 is exposed from each opening 39.

  On the other hand, a coil stator 40 is attached to the back surface of the magnet cover 32. FIG. 6 shows the coil stator 40. The coil stator 40 includes iron cores 41 arranged radially, and a coil 42 is wound around each iron core 41. An attachment boss 43 is provided on the back surface of the magnet cover 32, and the coil stator 40 is attached to the magnet cover 32 by fastening the coil stator 40 to the attachment boss 43 with a bolt 44.

In the magnet device 31 configured as described above, the outer rotor 36 is provided with a metal cover 38 that protects the magnet 37. When the magnetic flux of the magnet 37 passes through the cover 38, an eddy current is generated in the cover 38, It becomes a factor of iron loss.
Therefore, by forming the opening 39 in the cover 38, the portion of the cover 38 through which magnetic flux passes is reduced. Thereby, generation | occurrence | production of the eddy current in the cover 38 can be suppressed and an iron loss can be reduced. The shape and number of the openings 39 are not limited, but it is preferable to increase the total area of the openings 39 as much as possible within a range that does not impair the function as the cover 38.

The magneto device 31 configured as described above constitutes a three-phase AC generator that generates electric power based on the principle of electromagnetic induction as the outer rotor 36 rotates around the coil stator 40 by the rotation of the crankshaft 19.
As the AC generator, generally, a three-phase AC generator 1 in which three coils 2, 3, 4 are star-connected is used as shown in FIGS. 7 and 8. In the case where the outer shape of the generator is limited, such as a motorcycle, a permanent magnet AC generator with a simple structure is often used. In this case, the charging of the battery B by the AC generator 1 is controlled by a charging control device called rectifier, which is responsible for rectification and voltage control.

As a battery charge control device, there is a charge control device called a short system as shown in FIG.
As shown in FIG. 7, the diodes 101 and 102 are connected in series with the same forward direction, and one end of the coil 2 is connected between the diodes 101 and 102. Similarly, the diodes 103 and 104 are connected in series with the same forward direction, one end of the coil 3 is connected between the diodes 103 and 104, and the diodes 105 and 106 are connected in series with the same forward direction. One end of the coil 4 is connected between the diodes 105 and 106.
A positive line 107 is connected to the cathode side of the diodes 101, 103, 105 on the downstream side in the forward direction, and a ground line 108 is connected to the anode side of the diodes 102, 104, 106 on the upstream side in the forward direction. The battery B is connected between the positive line 107 and the ground line 108, and the battery B is charged with the output current of the diodes 101, 103, and 105.
A thyristor 109 is connected in parallel to the diode 102 with the forward direction reversed. Similarly, a thyristor 110 is connected in parallel to the diode 104 with the forward direction reversed, and a thyristor 111 is connected in parallel to the diode 106 with the forward direction reversed.
Each gate of the thyristors 109, 110, and 111 is connected to the control circuit 112, and the gate voltage is controlled by the control circuit 112. The control circuit 112 monitors the battery voltage, and turns off the thyristors 109, 110, and 111 when the battery voltage is less than a predetermined voltage. At this time, the battery B is charged with the output current of the diodes 101, 103, and 105 (see solid arrows in the figure). Then, when the battery voltage reaches a predetermined voltage, the control circuit 112 turns on the thyristors 109, 110, and 111 to return excess generated current to the generator (see the dotted arrow in the figure).

There is also a charge control device called an open system as shown in FIG.
As shown in FIG. 8, the thyristors 201 and 202 are connected in series with the same forward direction, and one end of the coil 2 is connected between the thyristors 201 and 202. Similarly, the thyristors 203 and 204 are connected in series with the same forward direction, one end of the coil 3 is connected between the thyristors 203 and 204, and the thyristors 205 and 206 are connected in series with the same forward direction. One end of the coil 4 is connected between the thyristors 205 and 206.
A positive line 207 is connected to the cathode side of the thyristors 201, 203, 205 on the downstream side in the forward direction, and a ground line 208 is connected to the anode side of the thyristors 202, 204, 206 on the upstream side in the forward direction. The battery B is connected between the positive line 207 and the ground line 208, and the battery B is charged with the output current of the thyristors 201, 203, and 205.
The gates of the thyristors 201 to 206 are connected to the control circuit 209, and the control circuit 209 controls the gate voltage. The control circuit 209 monitors the battery voltage, and turns on the thyristors 201 to 206 when the battery voltage is lower than a predetermined voltage. At this time, the battery B is charged with the output current of the thyristors 201, 203, and 205 (see solid line arrows in the figure). When the battery voltage reaches a predetermined voltage, the control circuit 209 turns off the thyristors 201 to 206 to shut off the AC generator 1 and the battery B (see the dotted arrow in the figure), that is, a circuit To open.

In the short system shown in FIG. 7, since power is always generated, there are all losses of power generation output, iron loss, and copper loss. Therefore, as shown by the characteristic line (two-dot chain line) in FIG. 9, electrical loss is relatively likely to occur in the entire region from the low rotation range to the high rotation range of the engine.
On the other hand, in the open system shown in FIG. 8, when the battery voltage reaches a predetermined voltage, the AC generator 1 and the battery B are cut off, so that no current flows through the coil and the copper loss is reduced. Therefore, as shown by the characteristic line (dashed line) in FIG. 9, it is possible to reduce the electrical loss in the low to medium rotation range as compared with the short method.
However, in the open system, when current does not flow through the stator, an eddy current is easily generated in the stator by the magnetic flux of the magnet, and the eddy current has a characteristic of increasing with increasing frequency, that is, with the engine speed. Therefore, as shown in FIG. 9, the iron loss increases particularly in the high engine speed range, and conversely, a phenomenon occurs in which the electrical loss increases as compared with the short system. The same can be said for the cover 38. In the open system, when current does not flow through the stator, eddy current is likely to be generated in the cover 38 by the magnetic flux of the magnet 37. It has characteristics that increase with the number, and the iron loss increases in the high engine speed range.

  Therefore, when the rotating electrical machine to which the present invention is applied is used as an AC generator driven by an engine to charge the battery by rectifying its output, the effect of reducing the iron loss can be obtained by combining with the open method described above. can get. That is, as shown by the characteristic line (solid line) in FIG. 9, generation of eddy currents in the cover 38 can be suppressed, particularly in a high engine speed range, and an increase in iron loss can be suppressed.

  As mentioned above, although this invention was demonstrated with various embodiment, this invention is not limited only to these embodiment, A change etc. are possible within the scope of the present invention. In the above embodiment, the case where the cover 38 is made of metal has been described. However, if the cover 38 is made of resin, no eddy current is generated in the cover 38 and iron loss can be reduced. Examples of the resin include polypropylene, ABS resin, polyethylene, and polyamide.

  19: Crankshaft, 31: Magnet device, 32: Magnet cover, 36: Outer rotor, 36a: Cylindrical part, 36b: Wall part, 37: Magnet, 38: Cover, 38a: Cylindrical part, 38b, 38: Support wall part, 39: opening, 40: coil stator

Claims (3)

A rotor having magnets;
A rotating electric machine comprising a coil stator around which a plurality of coils are wound,
A cover for protecting the magnet is attached to the rotor,
The rotating electrical machine according to claim 1, wherein the cover is made of metal and has an opening formed so as to expose a part of the magnet, or the cover is made of resin. The rotor is an outer rotor, and the magnet is disposed on the inner peripheral surface of the cylindrical portion,
2. The rotating electrical machine according to claim 1, wherein the cover is made of metal, has a cylindrical portion that covers the magnet, and a plurality of the openings are formed along the cylindrical portion. The rotating electrical machine according to claim 1 or 2 is an AC generator driven by an engine, and is a battery charge control device for rectifying its output and charging the battery,
A battery charge control device, characterized in that when the battery voltage reaches a predetermined voltage, the AC generator is disconnected from the battery.

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