JP3777880B2 - Electric motor rotor and electric motor cooling method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a motor rotor, and more particularly, to a motor rotor of a permanent magnet type synchronous motor such as a high-speed generator or a dynamometer using a permanent magnet as a rotor magnetic pole, and in particular, a motor rotor having excellent cooling efficiency and a motor cooling method. About.
[0002]
[Prior art]
Conventionally, various cooling methods for cooling an electric motor have been developed in order to prevent the electric motor from generating heat and causing problems due to various causes.
[0003]
For example, as an example where an electric motor generates heat, in a permanent magnet type synchronous motor using a permanent magnet as a magnetic pole of an electric motor rotor, when operating at high speed rotation, a shrink ring attached to prevent scattering of the magnet due to centrifugal force and It is mentioned that eddy currents induced in the permanent magnet by the high frequency of the fundamental frequency during driving, the time high frequency by the inverter, and the spatial high frequency by the slot ripple are generated as heat loss.
[0004]
On the other hand, a specific example of the cooling method for cooling the electric motor is disclosed in Japanese Patent Laid-Open No. 9-182374.
This cooling method will be briefly described with reference to FIG.
[0005]
FIG. 4 is a longitudinal sectional side view of an essential part of the electric motor showing a method for cooling the conventional electric motor.
In the electric motor 100 shown in FIG. 4, the permanent magnet 112 arranged on the outer periphery of the rotor 110 has a problem that irreversible demagnetization occurs due to heat when the temperature becomes high, mainly for the purpose of suppressing the occurrence of irreversible demagnetization. Then, the electric motor 100 is cooled.
[0006]
The rotor 110 of the electric motor includes a hollow rotor shaft 120 formed with an axial oil passage 122, first and second radial oil passages 116a and 116b penetrating the rotor core 114 in the axial direction, Communication oil passages 118 a and 118 b that connect the radial oil passages 116 a and 116 b and the hollow portion 122 in the rotor shaft 120 are formed.
As shown in the figure, the rotor core 114 and the stator core 134 are formed by laminating a number of electromagnetic steel plates.
[0007]
The conventional cooling method of the electric motor 100 is such that cooling oil is supplied from an unillustrated supply means for supplying cooling oil to the axial oil passage 122 in the rotor shaft 120, and this axial direction is indicated by an arrow in FIG. The coil end of the stator 130 is caused by the centrifugal force of the rotor 110 from the oil holes 119a and 119b through the first and second axial oil passages 116a and 116b from the oil passage 122 through the communication oil passages 118a and 118b. The electric motor 100 is cooled from the inside by being sprayed on 132.
[0008]
[Problems to be solved by the invention]
By the way, in the conventional motor cooling method, the axial oil passage is formed only in the vicinity of the rotor center, and the cooling efficiency of the rotor surface is low.
In addition, a cooling oil supply means such as a special pump for supplying the cooling oil to the oil passage of the rotor is required. For this reason, the structure of the electric motor body is complicated, the manufacturing cost increases, and the maintenance labor is excessive. There was inconvenience such as becoming.
In addition, the size of the oil droplets of the cooling oil sprayed from the oil holes is large, and there is a problem that the cooling oil does not reach the details of the internal structure of the electric motor and cooling spots (unevenness) occur.
[0009]
In particular, in a permanent magnet type synchronous motor, when the motor body is overheated, various adverse effects such as an increase in heat loss in the shrink ring and the permanent magnet appear, and the efficiency of cooling not only the motor rotor but also the entire motor is excellent. A cooling method is essential.
[0010]
An object of the present invention is to solve the above problems (problems), and to provide a motor rotor and a motor cooling method that have a simple structure and excellent cooling efficiency.
[0011]
[Means for Solving the Problems]
In order to solve the above-described problems, in the motor rotor of the present invention, in the motor rotor according to claim 1, in the motor rotor, the rotor shaft having a hollow portion serving as a path for cooling oil, and the hollow portion of the rotor shaft communicate with each other. And one or two or more first oil passages formed in the radial direction of the motor rotor, and communicated with the first oil passage, and formed along the rotational direction on the circumferential surface of the motor rotor or in the vicinity of the surface. One or two or more second oil passages are formed, and communicated with the second oil passage, and are formed on the circumferential surface of the motor rotor or in the vicinity of the surface in the axial direction to the vicinity of the end surface of the motor rotor. One or two or more third oil passages, a third oil passage communicating with the third oil passage, an oil retaining portion formed in the vicinity of the end face of the motor rotor, a fluid retaining portion communicating with the oil retaining portion, Formed on the end face, the cross section is narrower than the oil retaining part Outlet having a shape has a structure in which a rotor core is formed.
[0012]
If comprised in this way, the cooling of the whole motor rotor will be performed efficiently efficiently.
In addition, due to the centrifugal force due to the high-speed rotation of the motor rotor and the action that the cooling oil is drawn out by friction with the air from the outlet, no special cooling oil supply means such as a pump is required, and the structure of the motor is simple. It can be.
[0013]
The electric motor rotor according to claim 2, wherein a groove is formed on a surface of the rotor core in the electric motor rotor in the permanent magnet type electric motor using a permanent magnet as a magnetic pole of the rotor, and the permanent magnet is fitted to the outer peripheral surface of the rotor core. Thus, the second oil passage and the third oil passage were formed.
[0014]
With such a configuration, even in the permanent magnet electric motor, it is possible to improve the efficiency of cooling and facilitate the formation of the second and third oil passages.
[0015]
In the motor rotor according to claim 3, the shape of the blowout port is configured to be a shape suitable for discharging the cooling oil such as a nozzle in the form of a spray.
[0016]
With such a configuration, the cooling oil efficiently forms a mist, so that the cooling oil penetrates into the details of the stator and the cooling efficiency can be further enhanced.
[0017]
The motor cooling method according to claim 4, wherein in the motor rotor according to any one of claims 1 to 3, cooling oil is supplied to a hollow portion in the rotor shaft, and the first to third oil passages are provided. The motor rotor is cooled substantially by passing through the nozzle, and the cooling oil is blown out in a spray form from the blow-out port, and the mist-like cooling oil is sprayed into the stator to cool the motor.
[0018]
In the case where the motor is cooled using the rotor of the motor of the present invention, specifically, an efficient cooling method can be obtained by doing so.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
The motor rotor of the present invention will be described with reference to FIGS.
FIG. 1 is a side view showing a main configuration of an embodiment of an electric motor 80 using an electric motor rotor 10 of the present invention.
FIG. 2 is a front view of the motor rotor 10 of the present invention shown in FIG.
FIG. 3 is an enlarged side view of the main part indicated by A in FIG.
[0020]
The motor rotor shown in the present embodiment is used as a permanent magnet type synchronous motor (hereinafter simply referred to as “motor”), which is a type using a permanent magnet as a magnetic pole of the motor rotor. An explanation shall be given.
[0021]
First, as shown in FIG. 1, the electric motor 80 includes a stator 70 and the electric motor rotor 10 of the present invention as main components.
The electric motor rotor 10 includes a rotor shaft 30, a rotor core 12, and a permanent magnet 14 that is fitted on the outer peripheral surface of the rotor core 12 and serves as a magnetic pole of the electric motor rotor 10.
In FIG. 1, 72 is a coil end of a coil for exciting the stator 70, and 20 is a shrink ring.
[0022]
Next, the structure of the electric motor rotor 10 of the present invention will be described in detail.
As described above, the electric motor rotor 10 includes the rotor shaft 30 and the rotor core 12, but the rotor shaft 30 is formed with a hollow portion 30a serving as a path for cooling oil supplied from a cooling oil supply means (not shown). Yes.
[0023]
Further, in the rotor core 12 of the electric motor rotor 10, two first oil passages 40 communicating with the hollow portion 30a of the rotor shaft 30 are formed in the radial direction of the electric motor rotor 10, as shown in FIG.
[0024]
Further, a groove communicating with the first oil passage 40 is formed on the surface of the rotor core 12 along the rotation direction, and the second oil passage 50 is configured by fitting the permanent magnet 14 to the rotor core 12. .
FIG. 1 shows a structure in which two second oil passages 50 are formed.
[0025]
Similarly, a groove communicating with the second oil passage 50 is formed in the axial direction to the vicinity of the side surface of the rotor core 12, and the third oil passage 60 is configured by fitting the permanent magnet 14 to the rotor core 12. To do.
FIGS. 1 and 2 show a structure in which eight third oil passages 60 are formed.
In this way, when grooves are formed on the surface of the rotor core 12 and the permanent magnets 14 are fitted to form the second and third oil passages 50 and 60, the oil passages 50 and 60 of the rotor core 12 are formed. Processing becomes easy.
[0026]
On the other hand, as shown in the enlarged views of the main part in FIGS. 2 and 3, an oil retaining portion 62 communicating with the third oil passage 60 is provided in the vicinity of the end surface of the motor rotor 10 along the vicinity of the outer peripheral surface of the rotor core 12. A blowout port 64 that is formed in a ring shape and communicates with the oil retaining portion 62 on the end surface of the motor rotor and has a shape whose cross section is narrower than the oil retaining portion is also provided along the vicinity of the outer peripheral surface of the rotor core 12. It is formed in a ring shape.
In this manner, when the oil retaining portion 62 and the blowout port 64 are formed in a ring shape on the end surface of the rotor core 12 or in the vicinity thereof, these forming processes can be facilitated.
[0027]
With the above configuration, the basic operation of the motor rotor 10 and the cooling method of the motor 80 according to the present invention will be described with reference to FIGS.
[0028]
First, as described above, the cooling oil supply means (not shown) and the hollow portion 30a of the rotor shaft 30 are communicated, and cooling oil is supplied as necessary.
The cooling oil supplied to the hollow portion 30a of the rotor shaft 30 communicates with the hollow portion 30a and is sequentially supplied to the two first oil passages 40 formed in the rotor core 12 in the radial direction.
[0029]
At this time, when the cooling oil passes through the hollow portion 30a of the rotor shaft 30 and the two first oil passages 40, the rotor core 12 is cooled from the inside.
Further, when the motor rotor 10 rotates at high speed, the cooling oil is automatically conveyed to the vicinity of the surface of the rotor core 12 by centrifugal force without using a special supply means such as a pump.
[0030]
Next, the cooling oil is formed on the surface of the rotor core 12, and the two second oil passages 50 communicated with the first oil passage 40 and the eight third oil passages communicated with the second oil passage 50. The rotor core 12 is cooled from the surface by passing through the oil passage 60.
[0031]
As described above, when the cooling oil passes through the hollow portion 30a of the rotor shaft 30 and the first to third oil passages, the entire motor rotor 10 is substantially cooled.
[0032]
Further, as shown in FIG. 3, oil retaining portions 62 are prepared in the vicinity of both end faces of the rotor core 12, and the cooling oil that has passed through the first to third oil passages 40, 50, 60 is once in this oil. Collected in the fastening part 62.
This prevents the occurrence of blowout spots when blown from the blowout port 64.
[0033]
Further, as shown in FIGS. 2 and 3, blowout ports 64 communicating with the oil retaining portions 62 are provided on both end surfaces of the rotor core 12. The cooling oil staying in the vicinity of the air outlet 64 due to the high-speed rotation of the motor rotor 10 is drawn out by friction with air, but the cross section of the air outlet 64 is narrower than the cross section of the oil retaining portion 62 and is drawn out. The shape is suitable for being sprayed in a mist form.
[0034]
Thus, by providing the outlet 64 on the end face of the rotor core 12, it becomes possible to efficiently blow out the cooling oil, while the cooling oil is sprayed in the form of a mist so that the inside of the electric motor 80, for example, FIG. Since the cooling oil can easily enter the details of the stator core 74 shown in FIG. 1 and the cooling efficiency of the electric motor 80 can be increased, various inconveniences caused by overheating of the electric motor 10 can be solved.
[0035]
In addition, since centrifugal force due to rotation of the motor rotor 10 and cooling oil blowing action due to friction with air can be used, special cooling oil supply means such as a pump for forcibly circulating in the motor rotor 10 Therefore, the structure of the main body of the electric motor 80 can be simplified, the manufacturing cost can be suppressed, and the maintenance labor can be reduced.
[0036]
The motor rotor of the present invention is not limited to the above embodiment, and various modifications can be made.
For example, in the above-described embodiment, the second and third oil passages have been described with a configuration in which grooves are formed on the surface of the rotor core and permanent magnets are fitted on the outer peripheral surface of the rotor core. An oil passage may be formed by forming a through hole in the vicinity of the surface.
[0037]
In the above embodiment, the shape of the air outlet has been described as being formed in a ring shape on the end surface of the rotor core. However, depending on the rotational speed of the motor rotor, for example, the air outlet may be shaped like a nozzle to improve the spray efficiency. Of course, it may be further increased.
[0038]
【The invention's effect】
Since the motor rotor and the motor cooling method of the present invention are configured as described above, they have the following excellent effects.
(1) If it comprises as described in Claim 1, the whole cooling of an electric motor rotor will come to be performed efficiently efficiently.
(2) Further, the centrifugal force due to the high-speed rotation of the motor rotor and the action that the cooling oil is drawn out by the friction with the air from the blow-out port eliminates the need for special cooling oil supply means such as a pump, and the structure of the motor It can be simple.
[0039]
(3) If comprised as described in Claim 2, it will become possible also in a permanent-magnet-type electric motor to aim at the efficiency improvement of cooling and the formation process of a 2nd, 3rd oil path.
[0040]
(4) As described in claim 3, when the shape of the blowout port is a shape suitable for discharging the cooling oil in the form of a nozzle or the like in a spray form, the cooling oil is efficiently mist-shaped. Therefore, the cooling oil penetrates into the details of the stator, and the cooling efficiency can be further enhanced.
[0041]
(5) If it is set as the cooling method of the electric motor of Claim 4, it can be set as the efficient cooling method.
[Brief description of the drawings]
FIG. 1 is a side view showing an embodiment of an electric motor using an electric motor rotor of the present invention.
FIG. 2 is a front view showing an embodiment of an electric motor rotor of the present invention.
FIG. 3 is an enlarged side view of a main part of FIG. 1;
FIG. 4 is a longitudinal side view showing a configuration of a conventional electric motor.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10: Electric motor rotor 12: Rotor core 30: Rotor shaft 30a: Rotor shaft hollow part 40: 1st oil path 50: 2nd oil path 60: 3rd oil path 62: Oil retaining part 64: Outlet 80: Electric motor

Claims (4)

In the motor rotor,
A rotor shaft having a hollow portion serving as a cooling oil path;
One or two or more first oil passages communicating with the hollow portion of the rotor shaft and formed in the radial direction of the motor rotor;
One or two or more second oil passages that communicate with the first oil passage and are formed along the rotational direction on or around the circumferential surface of the motor rotor;
One or two or more third oil passages that communicate with the second oil passage, are formed in the axial direction on the circumferential surface of the motor rotor or in the vicinity of the surface, and near the end face of the motor rotor;
An oil retaining portion that communicates with the third oil passage and is formed in the vicinity of the end face of the motor rotor;
A motor rotor, comprising: a rotor core that communicates with the oil retaining portion, is formed on an end surface of the motor rotor, and has a blowout port having a shape whose cross section is narrower than the oil retaining portion. In the motor rotor in the permanent magnet motor using the permanent magnet as the magnetic pole of the rotor,
A groove is formed on the surface of the rotor core, and the second magnet passage and the third oil passage are formed by fitting the permanent magnet to the outer peripheral surface of the rotor core. The electric motor rotor according to Item 1. The electric motor rotor according to claim 1 or 2, wherein a shape of the blowout port is a nozzle shape or the like suitable for discharging the cooling oil in a spray form. The motor rotor according to any one of claims 1 to 3,
Supply cooling oil to the hollow portion in the rotor shaft,
By passing through the first to third oil passages, the entire motor rotor is cooled,
Cooling oil is blown out in a spray form from the blowout port,
A method for cooling an electric motor, wherein the electric motor is cooled by spraying mist-like cooling oil inside the stator.

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