JP2679759B2 - Engine driven permanent magnet generator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a generator using a permanent magnet as a field, and more particularly to a ventilation cooling structure thereof.

[0002]

2. Description of the Related Art A portable engine welder combined with a generator is widely used for welding work outdoors. This is because, in an environment where it is difficult to obtain power, such as in the field, it is not possible to obtain power even for machining equipment and lighting equipment, and it is required that these power supplies be also supplied from the welding machine. Is.

Therefore, a welding generator, which is configured as a rotary field type synchronous generator and produces an output for an auxiliary power source in addition to an output for welding, is widely used.

Most of the generators of this kind are 3600 r as a 2-pole or 4-pole generator in order to obtain an output for an auxiliary power source having a commercial power source frequency according to the engine speed.
pm-2 pole-60Hz or 1800rpm-4 pole-6
On the other hand, the welding output is a DC arc welding output obtained by full-wave rectifying the three-phase AC output.

As a result of the two-pole or four-pole rotating field type as described above, the generator 1 and the engine 2 must be connected to each other to become a considerably large machine. For example, even if a generator is installed in a 150A class welding machine, the rotor core diameter is 140mmφ, and a stacking thickness of about 60mm is required. This core is provided with a field winding and the stator is wound with an armature. Considering the coil end when the wire is applied, the axial length exceeds 120 mm. The reason for the increase in size is to cope with the temperature rise due to the field winding wound around the rotor.
Such a large size is inconvenient because it lacks portability, and there is a demand for smaller size and lighter weight.

However, in the generator having both the field winding and the armature winding as described above, the heat generated in both windings acts on each other, which easily causes a temperature rise inside the generator. Therefore, the size of the coil cannot be reduced unless a structure capable of favorably discharging the heat generated by the winding is adopted.

For this reason, a fundamental change such as the use of a permanent magnet instead of the field winding is required for a portable welding generator.

Considering the field of electric motors having a common element with a generator as a rotary electric machine, a magnet type electric motor provided with a rotating magnetic field by a permanent magnet is considered as a solution to the problem of temperature rise of the field winding. Has been commercialized. In order to obtain high magnetic properties, rare earth magnets, especially samarium cobalt magnets, are widely used.

This samarium-cobalt magnet has magnetically sufficient characteristics, and can be said to be suitable without problems in the case where a constant output is constantly generated such as an electric motor or an ordinary generator.

On the other hand, a welding generator has a problem. In other words, the welding work is repeated short circuit and open circuit and the reaction magnetic flux is large, and in addition to the problem of vibration transmitted from the engine as a drive source, the problem of intermittent operation of the welding machine, which is almost 10 minutes, and the steady load. Without a large current short-
The braking and vibration problems associated with repeated opening are added, and the magnets are required to have considerable mechanical strength.

In the actual test, the samarium-cobalt rare earth magnet was insufficient in strength and the magnet was damaged.

Therefore, a neodymium-iron-boron rare earth magnet was examined as another rare earth magnet having excellent mechanical strength.

However, as shown in FIG. 6, this neodymium-iron-boron rare earth magnet has a temperature characteristic of the residual magnetic flux density worse than that of the samarium cobalt rare earth magnet, and it is transmitted from the engine like an engine-driven generator. It has been found that when the temperature rise due to heat and radiant heat is large and reaches 100 ° C. or higher, the magnetic characteristics of the magnet are not recovered.

Therefore, it is necessary to take sufficient measures to cool the inside of the generator.

The present invention has been made in consideration of the above points, and in order to construct a field using a permanent magnet having a problem in temperature characteristics, an internal element of an electric machine centering on an armature winding is formed. An object of the present invention is to provide an engine-driven permanent magnet type generator that can effectively remove generated heat and cut off conduction heat from the engine as much as possible.

[0016]

In order to achieve the above object, according to the present invention, an armature winding is wound around an armature core according to claim 1, and the armature corresponds to a thickness of the armature core. A stator configured such that the ratio of the coil end length on one side of the armature core of the winding is about 1: 1, and a stator having the same thickness as the armature core, and having a field magnetic flux on the outer peripheral portion with respect to the field magnetic flux. A magnetic path having an effective cross-sectional area is formed, and a plurality of fan-shaped ventilation paths penetrating in the thickness direction of the field core are provided in the inner peripheral portion, and the stator is supported by an engine as a drive source in a cantilever manner. A field core fixed to the rotating shaft located at the center position of
Multi-pole permanent magnet plates, each of which is formed in a substantially square shape and has the same number as the number of field poles provided on the outer peripheral surface of the field iron core, and is provided at a position near the outer periphery of both end surfaces of the field iron core toward the stator. Having a centrifugal fan that ventilates in the direction, a housing that is fixed to the engine and supports the stator, and an air passage that is combined with the housing and that passes through the air passage from the surface on the side opposite to the engine of the rotor. And an enclosure having a cover forming the engine drive permanent magnet generator, and the cover in the engine drive permanent magnet generator according to claim 1, wherein: Provided is an engine-driven permanent magnet power generator provided with a baffle plate that regulates an air passage by a centrifugal fan.

[0017]

According to the structure of the first aspect, when the rotating field rotates due to the rotation of the rotor, the centrifugal fan provided on the outer periphery of the rotating field causes ventilation in the radial direction. This ventilation becomes ventilation in the radial direction along each side of the rotating field, and one side cools one side of the field iron core of the rotating field, and then cools the armature winding provided on the stator. Is discharged to the outside of the machine, and on the other side, the other side of the rotating field is cooled after passing through the fan-shaped ventilation passage provided in the rotating field, and then the armature winding provided on the stator. The wire is cooled and discharged outside the machine.
This cools both side surfaces of the rotor field. On the other hand, since the armature winding projects to both sides in the thickness direction of the armature core, radial airflow from the centrifugal fan passes while coming into contact with the armature winding, and removes the generated heat. This allows
The stator armature winding is cooled.

Further, in the rotating field, the heat conduction path extending from the central position to the outer peripheral surface is reduced by the fan-shaped ventilation path,
Engine heat from the rotating shaft located at the center position on the inner peripheral side is less likely to be conducted to the magnet plate on the outer peripheral surface of the rotating field.

According to the second aspect of the present invention, the air guide plate provided on the cover regulates the ventilation passage of the centrifugal fan so that the ventilation can be effectively involved in cooling.

[0020]

1 is a vertical sectional view showing an embodiment of the present invention. FIG. 1 shows a state in which an engine-driven welding generator 100 according to an embodiment of the present invention is cantilevered on an output shaft of an engine 200. The generator 100 includes a stator 110 fixed to a housing 101 mounted on the output shaft side of an engine body 201 by a through bolt 102, and a rotor 120 fixed to an output shaft 202 of an engine by a bolt 203. It is the main component. On the open side of the housing 101,
The top cover 103 is attached.

As will be described later, the stator 110 has a stator core, that is, an armature core 111 and an armature winding 112, and the output generated in the armature winding 112 is frequency-converted by an inverter (not shown) and output. To be done. The armature core 111 has two protrusions 111 a, one for engaging with the housing 101 and one for engaging with the top cover 103, on the outer periphery of both end surfaces thereof, and the armature core 111 is fixed to the housing 101. Then, the top cover 103 is fixed to the armature core 111. On the other hand, an armature winding groove 111b is provided on the inner peripheral surface of the armature core 111, and the armature winding 112 is inserted therein.

The rotor 120 is a magnet plate 122 of a rare earth magnet forming a field magnetic pole on the outer peripheral surface of the field iron core 121.
Is fixed, and a centrifugal fan 123 is provided near the outer circumference of both side surfaces to form a permanent magnet rotating field. The field iron core 121 has four ventilation passages 1 each having a fan-shaped cross section.
21a is provided, and the outer peripheral portion of the field iron core is separated from the inner peripheral portion by air in the portion of the ventilation passage 121a, and only four spoke-shaped portions that separate the four fan-shaped ventilation passages 121a from each other are provided. The outer peripheral portion of the field core is connected to the inner peripheral portion. A magnet plate 122 of a rare earth magnet is fixed to the outer peripheral surface of the field iron core 121, and the inner peripheral surface is fixed to the engine output shaft 202.

In order to construct the rotor 120, there is a problem of how to set the number of magnetic poles. (1) most effectively cooling the magnet plate of the rotor, (2) effectively cooling the armature winding, (3)
It is necessary to pay attention to the three points of forming the magnet plate in a square shape in terms of magnetic efficiency.

First, (1) In order to most effectively cool the magnet plate of the rotor, while forming a magnetic path for allowing a sufficient amount of magnetic flux to pass under the magnet plate in the field iron core, A fan-shaped ventilation passage is provided on the inner peripheral side to cool a portion of the field iron core as close to the magnet plate as possible. For this,
It is desirable to have a multi-pole structure in which the distance to the adjacent magnetic poles is small so that the thickness of the field core for the magnetic path can be made as thin as possible.

As a result of examining various configurations, the 14-pole configuration was the most suitable for the conditions.

Next, (2) in order to effectively cool the armature winding, it is necessary to apply a large amount of cooling air to the armature winding. Therefore, if the thickness of the armature core is reduced in order to reduce the length of the portion of the armature winding in the armature core, the thickness of the field core is also reduced. This reduces the size of the magnet plate and reduces the magnetic flux density of the field magnetic field. As a result, it is impossible to excessively polarize.

The best results were obtained by allocating the ratio of the thickness of the iron core of the stator to the protruding length on both sides of the armature winding to 1/3, 1/3, 1/3. As a result of examining various configurations on the premise of this, 14 poles were the most suitable for the condition.

(3) In order to form the magnet plate in a square shape, it is necessary to properly select the number of field magnetic poles.
This is to make the generator outer diameter equal to the engine outer diameter,
This is to consider that the magnet is not downsized.

As a result of examining various configurations, the outer diameter of the generator could be made almost the same as the outer diameter of the engine when 14 poles were used.

The following is a summary of these.

[0031]

[Table 1] A holding portion 101a for holding the armature core 111 is provided on the open surface of the housing 101, and an exhaust hole 101b is provided on the outer peripheral surface. And the housing 101
Along with this, a top cover 103 which constitutes an enclosure and accommodates the stator 110 and the rotor 120 therein is provided with an intake hole 103a for intake air from the end surface on the side opposite to the engine in this embodiment, and an exhaust hole is provided on the outer peripheral surface. 1
03b is provided.

Therefore, when the rotor 120 rotates, two ventilation passages are formed from the intake hole 103a to the two exhaust holes 103b and 101a through the centrifugal fan 123, as shown by the curved line in the figure. .

With these two ventilation paths, the stator 110 is
And the ventilation cooling of the rotor 120 is performed. Of these, the stator 110 mainly removes the heat generated by the armature winding 112 by applying cooling air to the portion of the armature winding 112 protruding from the armature core 111. The armature winding 112 has the thickness of the armature core 111 and the armature winding 1
The projection length of 12 has a ratio of 1: 2, which is 1/3 of that.
There is a weakness in the winding groove 111a of the armature core 111,
/ 3 or more is exposed from the armature core 111. As a result, most of the heat generated by the current flowing through the armature winding 112 is removed by the cooling air.

At this time, although less than the heat generated by the armature winding 112, the heat generated by iron loss in the armature core 111 is also removed. Also, the rotor 1
In 20, the field core 121 is cooled by the cooling air flowing along both side surfaces of the field core 121 and the cooling air flowing through the fan-shaped ventilation passages 121a. As a result, the field core 12
The temperature rise of the magnet plate 122 provided on the outer peripheral surface of No. 1 is prevented, and the magnetic characteristics of the magnet plate 122 are prevented from being deteriorated by heat.

In addition to such positive exhaust heat cooling, the field core 121 is designed to prevent temperature rise by suppressing conduction heat. This is made by the field iron core 121 provided with a plurality of fan-shaped ventilation passages 121a.
21a reduces the radial cross-sectional area of the field iron core 121, so that the field iron core 121 from the engine output shaft 202 is reduced.
Even if heat is conducted to the inner peripheral portion of the engine, conduction of engine heat to the outer peripheral portion is significantly suppressed. If the ventilation cooling is effectively performed, the temperature of the outer peripheral portion of the field iron core 121 does not rise.

FIG. 2 shows an embodiment of a fan-shaped ventilation passage provided in the field iron core 121. In this embodiment, four fan-shaped ventilation passages 121 are provided in the cross section of the field iron core 121.
a is provided. As a result, the outer peripheral portion and the inner peripheral portion of the field iron core 121 are separated from each other by air in the fan-shaped ventilation passage 121a and are connected by the four spoke-shaped portions 121b.

As a result, the engine heat from the engine output shaft 202 is transmitted to the inner peripheral portion of the field iron core 121, but is further suppressed from being transmitted to the outer peripheral portion.

The cooling air that flows through the fan-shaped ventilation passage 121a removes heat from the wall surface when flowing along the wall surface of the fan-shaped ventilation passage 121a, and cools the field core 121. The wall surface area of the fan-shaped ventilation passage 121a is the largest at the outermost periphery of the fan, that is, the arc portion near the outer periphery of the field iron core 121, and removes much heat from this portion. As a result, the outer peripheral portion of the field iron core 121 is effectively cooled. Moreover, as shown in FIG. 2, by providing a large number of grooves extending in the arc-shaped portion near the outer periphery in parallel to the axial direction or slightly obliquely, the wall surface area in contact with the cooling air is increased, and the cooling effect is further enhanced. When the grooves are deepened to reduce the thickness of the iron cores for partitioning the grooves so as to be arranged obliquely with respect to the axial direction, the iron cores of the partitions can also serve as fan blades to obtain an axial fan effect.

[0039]

According to the structure of the first aspect of the present invention, the armature is provided along one side surface of the field core which is axially introduced by the cooperation of the centrifugal fan provided in the rotating field and the fan-shaped ventilation passage. Ventilation to reach the winding and ventilation to the armature winding along the other side of the field core after passing through the fan-shaped ventilation passage can be performed, and the rotating field and armature The winding can be cooled effectively. Moreover, in the rotating field, the heat conduction path connecting from the inner peripheral portion to the outer peripheral portion is small due to the fan-shaped ventilation passage, so that it is difficult for heat to be conducted from the rotating shaft in the inner peripheral portion to the magnet plate in the outer peripheral portion.

According to the second aspect of the invention, the air guide plate provided on the cover can regulate the air passage by the centrifugal fan so that the air passage can be effectively involved in the cooling.

[Brief description of the drawings]

FIG. 1 is a view showing a vertical section of an embodiment of the present invention.

FIG. 2 is a partially crushed front view of a field iron core according to an embodiment of the present invention.

FIG. 3 is a diagram showing temperature-demagnetization factor characteristics of a neodymium-iron-boron-based rare earth magnet.

[Explanation of symbols]

 100 Generator 101 Housing 101a Holding part 101b Exhaust port 102 Penetration bolt 103 Cover 103a Intake port 103b Exhaust port 103c Engaging claw 103d Baffle plate 110 Stator 111 Armature iron core 111a Armature winding groove 111b Peripheral protrusion 111c Outer peripheral recess 112 Armature Winding 120 Rotor 121 Field Iron Core 121a Fan-shaped Ventilation Path 121b Field Iron Core Remaining Part 122 Magnet Plate 123 Centrifugal Fan 201 Engine Body 202 Engine Output Shaft 203 Bolts

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hirotaka Yamamoto 4-2-2 Kamitakata, Nakano-ku, Tokyo Denyo Co., Ltd. (56) References JP 62-221839 (JP, A)

Claims (2)

(57) [Claims] 1. An armature winding is wound around an armature core, and a ratio of one side coil end length of the armature core of the armature winding to a thickness of the armature core is about 1: 1. A stator configured as described above, and a magnetic path having a thickness equivalent to that of the armature core and having a cross-sectional area effective for field magnetic flux is formed in an outer peripheral portion and the field core is formed in an inner peripheral portion. A plurality of fan-shaped ventilation passages penetrating in the thickness direction of the field iron core, which are cantilevered by an engine as a drive source and fixed to a rotating shaft located at the center position of the stator, each having a substantially square shape. The same number of multi-pole permanent magnet plates as the number of field poles formed on the outer peripheral surface of the field iron core, and provided in positions near the outer periphery of both end surfaces of the field iron core to ventilate radially toward the stator. A rotor having a centrifugal fan, fixed to the engine, An engine drive, comprising: a housing that supports a stator; and an enclosure that includes a housing that is combined with the housing to form a ventilation path that extends from the surface of the rotor opposite to the engine to the ventilation path. Permanent magnet type generator. 2. The engine-driven permanent magnet generator according to claim 1, wherein the cover is provided with a baffle plate that regulates a ventilation path of the centrifugal fan.