CN102420472A - Alternating current generator for vehicle - Google Patents

Abstract

An alternator for a vehicle, comprising: an excitation coil, a rotor core, and a stator core; The yoke part which is cylindrical and expands from the axial position of the yoke part to the outer peripheral direction is connected to the yoke part and formed as a claw-shaped magnetic pole part surrounding the excitation coil; the stator core is connected to the rotor core claw The outer circumference of the pole-shaped pole part is arranged oppositely, and it is composed of a laminated iron core and an armature coil; the outer radius of the yoke part of the rotor core is set to R2, the outer radius of the claw-shaped magnetic pole part is set to R3, and the ratio of R2/R3 is 0.53 ~0.51; the section of the yoke portion of the rotor core is set as S2, the root section of the claw-shaped magnetic pole portion is set as S3, the ratio of S3/S2 is 0.90 to 0.98, and the axial length of the stator core is set as L1, The length of the rotor core yoke is set to L2, and the ratio of L1/L2 is greater than 1.

Description

Alternator for vehicle

technical field

The present invention relates to a vehicle alternator mounted on a passenger car or a truck.

Background technique

In recent years, automotive alternators have been required to be miniaturized and to improve power generation capacity in the same volume specification. That is, it is demanded to provide a vehicle alternator that is small in size and high in output at a reasonable price.

In general, as shown in FIG. 1 , an alternator for a vehicle includes a field coil 2 , a stator core 3 and a rotor core 2 .

The rotor core is constituted by a Lundell-type iron core. As shown in FIG. 2 , this Lundell-type iron core includes a yoke portion 21 , a yoke portion 22 , and a claw-shaped magnetic pole portion 24 . The magnetic flux Φ flowing in this rotor core flows from the yoke portion to the yoke portion, the claw-shaped magnetic pole portion, and the magnetic flux flows from the claw-shaped magnetic pole portion to the stator core. The overall length of a general generator is determined by the length of the rotor in the axial direction (hereinafter referred to as the axial length). Accordingly, in order to design a compact generator, it is desirable to reduce the axial length of the rotor.

It is well known that the magnetic flux φ produced by the rotor core is expressed as:

(Magnetic flux Φ generated by the rotor) = (excitation coil AT) / (sum of reluctance of each part (yoke, yoke iron, claw pole, gap, stator core)).

Among them, "A" represents the current flowing through the magnetic field coil; "T" represents the number of turns of the magnetic field coil.

In order to increase the output by increasing the magnetic flux generated by the rotor, it is necessary to reduce the reluctance or increase the AT of the field coil.

In the existing structure shown in Figure 2, the magnetic circuit sections S1, S2, and S3 of each part of the rotor core are preferably substantially the same, and the axial length L2 of the yoke part of the rotor core is equal to the axial length L1 of the stator core. When it is necessary to increase the electrical output of the generator, it is necessary to increase the magnetic flux generated by the rotor core. In order to achieve an increase in the magnetic flux of the rotor core, it is necessary to increase the value of the coil "AT" (ie, increase the field coil) or decrease the reluctance. In order to increase the generated magnetic flux without changing the size of the rotor, the cross-sectional area of the field coil needs to be increased in order to strengthen the coil "AT", while the cross-sectional area of the corresponding part of the rotor magnetic circuit will be reduced. However, if the reluctance is to be reduced, the cross-sectional area of the magnetic circuit needs to be increased in order to reduce the reluctance, and at the same time the cross-sectional area of the magnetic field coil will be reduced, so the existing structure needs to consider a compromise between the two requirements .

In the existing structure shown in Figure 3, the magnetic circuit section S1 of each part of the rotor core is equal to S2, and S3 is much smaller than S2, and the axial length L2 of the yoke part of the rotor core is equal to the axial length L1 of the stator core. Smaller than S2, although a larger cross-sectional area of the magnetic field coil can be obtained, but the base S3 of the claw-shaped magnetic pole part is magnetically saturated, so the magnetic flux leaks along the axial direction, and the leakage of the magnetic flux leads to a decrease in the magnetic flux reaching the stator core, while the stator core The reduced magnetic flux in the generator reduces the electrical output of the generator.

In the existing structure shown in Fig. 4, the magnetic circuit sections S1, S2, S3 of each part of the rotor core are preferably substantially the same, the axial length L2 of the yoke part of the rotor core is smaller than the axial length L1 of the stator core, and the yoke The iron part is opposite to the stator core, and part of the magnetic flux flows directly from the yoke part to the stator core. Although this increases the magnetic flux flowing to the stator core, the magnetic circuit sections S1, S2, and S3 are basically equal, making the enhanced coil "AT" Still relatively difficult.

In the existing structure shown in Figure 5, the magnetic circuit section S1 of each part of the rotor core is equal to S2, and S3 is much smaller than S2, and the axial length L2 of the yoke part of the rotor core is smaller than the axial length L1 of the stator core. Since S3 is much smaller than S2, a larger cross-sectional area of the magnetic field coil can be obtained, but the base of the claw-shaped magnetic pole part is magnetically saturated. Therefore, although part of the magnetic flux can flow directly from the yoke portion to the stator core, the reluctance at the base of the claw-shaped pole portion suddenly increases, so that the total amount of magnetic flux flowing to the stator core is significantly restricted.

In the existing structure shown in Figure 6, the magnetic circuit section S1 of each part of the rotor core is equal to S2, and S3 is equal to 0.47~0.8 of S2 (converted from X ₁ /X ₂ =0.5~0.9), the rotor core yoke part The axial length L2 of the stator core is smaller than the axial length L1 of the stator core. Also because S3 is much smaller than S2, although a larger cross-sectional area of the magnetic field coil can be obtained, the base of the claw-shaped magnetic pole part still tends to be magnetically saturated. Therefore, although part of the magnetic flux can flow directly from the yoke portion to the stator core, the reluctance at the base of the claw pole portion is still large, resulting in a reduction in the total amount of magnetic flux flowing to the stator core.

In the existing field coil space, if the field coil "AT" is increased, if the field current increases, the heat generated by the field coil will increase, thus causing difficulty in cooling it, resulting in increased excitation loss and reduced power output efficiency. For this purpose, there are methods of improving the cooling characteristics of the field coil by using self-melting wires, using high thermal conductivity resin bobbins, and the like.

In addition, there are methods of reducing the air gap or increasing the stator core without changing the size and shape of the rotor core, in order to reduce the air gap and the reluctance of the stator core. However, the stator core is in the entire magnetic The proportion of resistance in the air gap is smaller than that of the rotor core. In addition, the size of the air gap is determined according to mechanical constraints, not electromagnetic constraints such as the working accuracy of the rotor and stator, the maximum speed, etc., so it is difficult to achieve.

Also, a magnet is inserted into the region between the claw-shaped magnetic pole portions to prevent leakage of magnetic flux, thereby increasing the amount of magnetic flux in the rotor core. In this case, the cost increases due to the use of the magnet and the device for holding the magnet, and the magnet may fly out of its original position at high rotational speed due to the centrifugal force.

Contents of the invention

In view of the above-mentioned problems and the magnetic circuit of the rotor core and the stator core has the characteristics of magnetic saturation, and the weight of the generator is closely related to the height of the stator core, it is comparable to increasing the field coil "AT" by increasing the space of the field coil Compared with that, the present invention reduces the reluctance by increasing the cross-section of the magnetic circuit and can effectively increase the magnetic flux flowing through the stator core, adopting the axial length L2 of the yoke part of the rotor core less than the axial length L1 of the stator core and appropriate The height of the stator core is limited, and at the same time, designs with properly dimensioned parts of the rotor core are used. These designs employ synergistic effects in order to provide vehicles with a compact, high-power generator with good output efficiency and low the cost of.

The technical solution of the present invention to solve the above-mentioned technical problems is: an alternator for vehicles, which has: an excitation coil, a rotor core and a stator core; The yoke portion on which the field coil is mounted is cylindrical, and the yoke portion expanded from the axial position of the yoke portion to the outer peripheral direction is connected to the yoke portion and formed into a claw shape surrounding the field coil. The magnetic pole portion; the stator core is arranged opposite to the outer circumference of the claw-shaped magnetic pole portion of the rotor core, and is composed of a laminated iron core and an armature coil; it is characterized in that: the outer radius of the yoke of the rotor core is set to R ₂ , and the claw-shaped The outer radius of the magnetic pole part is set as R ₃ , and the ratio of R ₂ /R ₃ is 0.53 to 0.51; the section of the yoke part of the rotor core is set as S2, and the root section of the claw-shaped magnetic pole part is set as S3, S3/S2 The ratio is greater than 0.9, the ratio of S3/S2 is 0.90-0.98, the axial length of the stator core is L1, the length of the rotor core yoke is L2, and the ratio of L1/L2 is greater than 1.

The above ratio of L1/L2 is more preferably from 1.10 to 1.40, most preferably 1.26.

In the present invention, the ratio of R ₂ /R ₃ is 0.53 to 0.51, which can provide a larger cross-sectional area of the excitation coil than the existing structure, so that a compact structure and high efficiency can be provided without increasing the field current. capable generator.

In the present invention, the ratio of S3/S2 is 0.90～0.98, such as 0.93, 0.95, 0.97, the magnetic flux density of the claw-shaped magnetic pole part can be in an optimal range, and at the same time, it can prevent the claw-shaped magnetic flux density caused by too small S3. Magnetic saturation of the magnetic pole portion reduces the power output of the generator.

In the present invention, the ratio of L1/L2 is greater than 1, preferably set to 1.10-1.40, such as 1.26. Magnetic flux can flow directly from the yoke portion into the stator core.

Description of drawings

Fig. 1 is a sectional view of a main part of an alternator for a vehicle according to the present invention.

Fig. 2 is a schematic diagram of the magnetic flux flowing between the stator core and the rotor core in the existing structure, wherein S1=S2=S3; L1=L2 of the rotor core.

Fig. 3 is a schematic diagram of the magnetic flux flowing between the stator core and the rotor core in the existing structure, wherein S1=S2, S3<S2; L1=L2 of the rotor core.

Fig. 4 is a schematic diagram of the magnetic flux flowing between the stator core and the rotor core in the existing structure, wherein S1=S2=S3 of the rotor core; L1>L2.

Fig. 5 is a schematic diagram of the magnetic flux flowing between the stator core and the rotor core in the existing structure, wherein S1=S2, S3<S2; L1>L2 of the rotor core.

Fig. 6 is a schematic diagram of the magnetic flux flowing between the stator core and the rotor core in the existing structure, wherein S1=S2, S3=0.47S2-0.80S2 of the rotor core; L1>L2.

Fig. 7 is a schematic diagram of an equivalent magnetic circuit of a stator core and a rotor core according to the present invention.

Fig. 8 is a sectional view of a rotor core in an alternator for a vehicle according to the present invention.

FIG. 9 is a view of FIG. 8 viewed from the direction of the cylindrical portion of the rotor core.

Fig. 10 is an enlarged view of Fig. 8 viewed from the direction of the cylindrical portion of the rotor core.

Fig. 11 is a graph showing the relationship between the power output of the generator per unit weight and the L1/L2 ratio when the ratio of S3/S2 is 0.96.

FIG. 12 is a schematic diagram of the relationship between the ratio of S3/S2 and the magnitude of the magnetoresistance when the ratio of L1/L2 is 1.26.

Fig. 13 is a graph showing the relationship between the power output of the generator per unit weight and the S3/S2 ratio when the ratio of L1/L2 is 1.26.

FIG. 14 is a graph showing the relationship between the power output of the generator per unit weight and the L1/L2 ratio when the ratio of R2/R3 is 0.53.

FIG. 15 is a graph showing the relationship between the power output of the generator per unit weight and the R2/R3 ratio when the ratio of L1/L2 is 1.26.

Detailed ways

Referring to Fig. 1, according to an embodiment of the present invention, a vehicle generator comprises a rear shell, a pulley, a front bearing, a rear bearing, a brush, a slip ring, a cooling fan, a rectifier, a shaft, a voltage regulator, an exciting coil, and a rotor core and stator core. The stator core is used as an armature, and the rotor core is used to generate a magnetic field. The rotor core includes a cylindrical yoke part, a yoke part and a claw-shaped magnetic pole part. The casing supports the stator core and the rotor core. The rectifier is directly connected to the stator. , the rectifier converts alternating current to direct current, the voltage regulating device adjusts the field current to control the generated power, the transistor in the voltage regulating device is connected to the high voltage side of the field coil, so that when the generator is not working, the field coil can not bear the voltage. The rotor core rotates with the shaft, which is connected to a pulley and provides power to the vehicle engine (not shown) to drive and rotate.

The magnetic circuit will be described in detail below with reference to the drawings. The outer radius of the yoke portion of the rotor core is set as R ₂ , and the outer radius of the claw-shaped magnetic pole portion is set as R ₃ ; the section of the yoke portion of the rotor core is set as S2, and the root section of the claw-shaped magnetic pole portion is set as S3; The axial length of the stator core is L1, and the length of the rotor core yoke is L2.

Assuming that the number of pole pairs P of the rotor core is 6 pairs, X ₂ =13.5mm, R ₃ =50.15mm, the gap δ of the generator (the gap between the stator core 2 and the rotor core 3) is equal to the commonly used value, namely 0.35mm, when the structure of the claw-shaped magnetic pole is reduced equidistantly from the inner diameter side to the outer diameter side:

The cross-sectional area S2 of the reference yoke portion is as follows:

S2=W·X ₂

W＝2Sin15 ⁰ ·πR ₃ /(2P)

Where "P" represents the number of pole pairs of the rotor core

The cross-sectional area S3 of the root of the claw-shaped magnetic pole is as follows:

S3=π{R ₃ ² -(R ₃ -X ₁ ) ² }/(2P)

When X ₁ =0.5X ₂ , S3/S2=0.47

When X ₁ =0.9X ₂ , S3/S2=0.80

When X ₁ =X ₂ , S3/S2=0.90

As mentioned above, the ratio of R ₂ /R ₃ is less than 0.54, such as 0.53; it can provide a larger cross-sectional area of the excitation coil than the existing structure, so that a compact structure and a High performance generator.

In the present invention, as shown in FIG. 9, for example: when the number of magnetic pole pairs of the rotor core is 6, one side of the claw-shaped magnetic pole cross-sectional area is reduced to 15 degrees, and when X ₁ =X ₂ , S3/S2 is 0.9 or more, The outer diameter D ₀ of the stator core is 128mm, and the R ₃ of the claw-shaped magnetic pole part is equal to 50.15mm.

In the present invention, as shown in Fig. 10, for example: when the number of magnetic pole pairs of the rotor core is 6, when the cross-sectional area of the claw-shaped magnetic pole is less than 15 degrees on one side, S3/S2 is 0.9 or more, and the outer diameter of the stator core is 128mm , R ₃ of the claw pole part is equal to 50.15mm.

In the present invention, the ratio of S3/S2 is greater than 0.9, and the ratio of S3/S2 is preferably set to 0.90～0.98, such as 0.93, 0.95, 0.97, so that the magnetic flux density of the claw-shaped magnetic pole part can be in an optimal range, At the same time, it can prevent the magnetic saturation of the claw-shaped magnetic pole part due to too small S3, and reduce the power output of the generator.

In the present invention, the ratio of L1/L2 is greater than 1, preferably 1.10-1.40, such as 1.26, the magnetic flux can flow directly from the yoke part into the stator core, and the stator core will not be too long to increase the weight of the generator , affecting the electrical output of the generator per unit weight.

Fig. 10 is an enlarged view of Fig. 8 viewed from the direction of the cylindrical part of the rotor core. The cross-sectional area of the claw-shaped magnetic pole is reduced to a on one side, and S3 is changed by changing a.

The unilateral reduction of the cross-sectional area of the claw-shaped magnetic poles is preferably less than 15 degrees, preferably 0.

The advantages of the embodiments of the present invention are demonstrated through experiments. Figure 12 shows the relationship between S3/S2 and synthetic reluctance R and the experimental results. When the S3/S2 ratio and L1/L2 ratio are changed as parameters, the ordinate represents the synthetic reluctance R, and the abscissa represents the S3/S2 ratio. It can be seen sufficiently that by enlarging S3, the resultant reluctance R is greatly reduced. In particular, the effect is remarkable when L1/L2 is 1.26. This means that the reluctance of the claw-shaped magnetic pole portion of the magnetic flux Φ1 flowing through S3 and flowing from the claw-shaped magnetic pole portion into the stator through the gap is extremely high, and the reluctance here can be effectively alleviated by increasing S3. Setting S3/S2 to 0.9 or more as shown in the figure can reduce the combined reluctance R by about 5% or more. Furthermore, when L1/L2 is 1.26, that is, when S3/S2 is 1.0, the reluctance can be reduced by about 10%, so it is possible to provide an alternator with increased magnetic flux and high output.

In FIG. 11 , the ordinate represents the power output of the generator per unit weight. Experimental results show the relationship between generator power output per unit weight and L1/L2 ratio when S3/S2 is equal to 0.96.

In FIG. 13 , the ordinate represents the power output of the generator per unit weight. The experimental results show the relationship between the generator power output per unit weight and the S3/S2 ratio when the L1/L2 ratio is 1.26.

In FIG. 14, the ordinate represents the power output of the generator per unit weight. Experimental results show that when R ₂ /R ₃ is equal to 0.53, the relationship between the generator power output per unit weight and the L1/L2 ratio.

In FIG. 15, the ordinate represents the power output of the generator per unit weight. The experimental results show the relationship between the generator power output per unit weight and the _R2 / _R3 ratio when the L1/L2 ratio is 1.26.

It is fully illustrated from Fig. 11 to Fig. 16 that the selected parameters of the present invention are reasonable and can ensure that the power output of the generator per unit weight is above 31.5A/Kg.

In the embodiment of the present invention, the outer diameter of the stator core is 128 mm, and R ₃ of the claw-shaped magnetic pole portion is equal to 50.15 mm. Even when the outer diameter of the stator is 139mm, 144mm, the same good result can be obtained. When R ₃ of the claw-shaped magnetic pole part is set within the range of 50 mm to 60 mm, the parameter setting range of the embodiment of the present invention is effective. Equally good results are obtained when the number of pole pairs of the rotor core is equal to other values, such as 7 or 8.

Claims (5)

1. a vehicle-mounted dlternator has: magnet exciting coil, rotor core and stator core; Rotor core; It has Ivan Lendl sections core, and this Ivan Lendl sections core has the yoke portion of this magnet exciting coil of package, and this yoke portion is cylindric; The yoke that enlarges to peripheral direction from the direction of principal axis position of this yoke portion is connected and forms the claw-like magnetic pole piece of the said magnet exciting coil of encirclement with this yoke; Stator core, the periphery subtend configuration at rotor core claw-like magnetic pole piece is made up of laminated core and armature coil; It is characterized in that: the yoke portion outer radius of said rotor core is made as R ₂, the outer radius of claw-like pole parts is made as R ₃, R ₂/ R ₃Ratio be 0.53～0.51; The section of said rotor core yoke is made as S2, and the root section of claw-like magnetic pole piece is made as S3, and the ratio of S 3/S2 is 0.90～0.98, and the direction of principal axis length of said stator core is made as L1, and the length of rotor core yoke portion is made as L2, and the ratio of L1/L2 is greater than 1.

2. vehicle-mounted dlternator as claimed in claim 1 is characterized in that: the ratio of said L1/L2 is 1.10～1.40.

3. vehicle-mounted dlternator as claimed in claim 2 is characterized in that: the ratio of said L1/L2 is 1.26.

4. like claim 1 or 2 or 3 described vehicle-mounted dlternators, it is characterized in that: the one-sided of said claw-like magnetic pole sectional area is reduced into less than 15 degree.

5. vehicle-mounted dlternator as claimed in claim 4 is characterized in that: one-sided 0 degree that is reduced into of said claw-like magnetic pole sectional area.

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