JP3690920B2 - Sealed motor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electric motor used as a spindle motor of a machine tool or the like, and more particularly to a hermetic motor having a structure in which a rotor and a stator are hermetically sealed in a motor frame.
[0002]
[Prior art]
FIG. 11 shows an example of the configuration of a hermetic motor having a hermetic structure as a spindle motor. A rotor iron core 13 provided with a secondary conductor 13 a is fixed to the main shaft 11 via an attachment portion 12. The stator 15 includes a stator iron core 16 and a primary winding 17, and a three-phase alternating current flowing through the winding 17 forms a rotating magnetic field on the inner peripheral surface of the iron core 16. The inner peripheral surface of the iron core 16 is disposed so as to face the outer peripheral surface of the rotor iron core 13 through a minute gap, and the rotor 13 is rotationally driven by a rotating magnetic field formed by the stator 15. The stator iron core 16 is fixed to the inner peripheral surface of the motor frame 18. Similarly, the main shaft 11 is rotatably supported by bearings 20 and 21 provided on the motor frame 18. A portion 11a of the main shaft 11 that protrudes outside the motor frame 18 is connected to, for example, a turntable of a machine tool and rotationally drives it.
[0003]
[Problems to be solved by the invention]
However, since the conventional hermetic motor has a structure in which the motor frame seals the stator and the rotor, it is difficult to dissipate heat generated by the rotor and the stator, and the temperature increase of the stator winding or the temperature of the rotor is remarkably increased. There is a problem of doing. Since the stator iron core 16 is fixed to the motor frame 18, the generated heat is relatively easy to dissipate from the motor frame 18. However, since the rotor iron core 13 is located on the inner side, this heat dissipation is not easy. In particular, the temperature rise of the rotor iron core 13 results in the overall temperature of the main shaft 11 being increased, and the bearings 20 and 21. In addition, an abnormal temperature rise may be caused, which may cause an accident such as a decrease in bearing life or a burnout of the bearing.
[0004]
The present invention has been made in view of the above circumstances, and in particular, a sealed electric motor capable of efficiently transferring heat generated in the vicinity of the rotor and the spindle to the motor frame and suppressing the temperature rise of the spindle. The purpose is to provide.
[0005]
[Means for Solving the Problems]
Hermetic motor of the present invention includes a rotor which is fixed to the main shaft, a stator for rotating said rotor, a bearing for rotatably supporting the spindle, met hermetic motor enclosed structure to the motor frame A gap groove for blowing air is provided on the inner peripheral surface of the mounting portion of the rotor iron core for fixing the rotor iron core to the main shaft, and the air can be blown in the axial direction along the main shaft with the rotation of the main shaft, A large number of gap grooves serving as ventilation paths are formed along the circumferential direction on the inner peripheral surface of the motor frame at the joint between the stator and the motor frame to which the stator is fixed, and the gap grooves are formed along the axial direction. Air arranged in a straight line, cooling water passages are arranged in the motor frame, and the cooling water circulates so that the motor frame is cooled and blown in the axial direction along the main shaft as the main shaft rotates. Is the motor It is cooled while passing through the air passage of the inner peripheral surface of the over-time, and is characterized in that the air is to cool the rotor and the main shaft portion as a circulating air.
[0006]
According to the present invention described above, a groove capable of blowing air is provided in the mounting portion of the rotor, and a gap groove capable of passing air is provided in the joint portion with the motor frame to which the stator is fixed. Thus, it is possible to form a circulating wind for transferring heat generated in the vicinity of the main shaft. That is, when the rotor rotates, the air in the vicinity of the main shaft is blown by the groove to form a circulating air, thereby transporting heat generated in the vicinity of the main shaft and transferring it to the motor frame. Therefore, the heat generated by the heat generation of the rotor can be released to the motor frame, and thereby the temperature rise of the main shaft and the bearing can be suppressed low.
[0007]
In the hermetic motor of the present invention , the structure of the mounting portion for fixing the rotor to the main shaft includes a cylindrical portion for fixing the rotor to the main shaft, and ribs standing on the cylindrical portion so that a space between the ribs is axially provided. is rotated in the circumferential direction along may be a blower capable of grooves in the axial direction. Thereby, since the space between ribs is made into the groove | channel which can ventilate in an axial direction, a circulating wind can be easily formed with rotation of a rotor. The heat transmitted to the vicinity of the main shaft by this circulating air can be transferred to the motor frame and dissipated.
[0008]
In the sealed electric motor of the present invention , the structure of the mounting portion that fixes the rotor to the main shaft may be provided with a gap groove capable of blowing air on the inner peripheral surface of the mounting portion that fixes the rotor to the main shaft. In the hermetic motor of the present invention , the structure of the mounting portion for fixing the rotor to the main shaft may be provided with a gap groove capable of blowing air on the outer peripheral surface of the main shaft for fixing the rotor to the main shaft. As a result, it is possible to form a circulating air with the rotation of the rotor, and in particular, a gap groove that can blow air is provided in the vicinity of the main shaft, which is suitable for cooling the main shaft and abnormal bearing portions. Temperature rise can be prevented.
[0009]
In the hermetic motor of the present invention, fins may be further provided on the inner peripheral surface of the motor frame. As a result, heat transfer to the motor frame can be enhanced by further providing fins with respect to the circulating air flowing through the gap groove provided at the joint between the stator and the motor frame. Therefore, the efficiency of cooling the circulating wind can be increased.
[0010]
Further, in the hermetic motor of the present invention, the motor frame Rukoto a cooling water passage, to heat transfer the heat carried by the circulating air to the motor frame, efficiently transfer by a motor frame and a water cooling structure The heated heat can be removed. Therefore, the cooling efficiency of the rotor, the stator, and the bearing portion can be increased as a whole, and in particular, the temperature rise near the main shaft can be efficiently suppressed.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the accompanying drawings. In addition, in each figure, the same code | symbol shows the same or equivalent part.
[0012]
FIG. 1 shows the structure of a hermetic motor related to the present invention. As shown in the figure, a structure in which a rotor iron core 13 fixed to a main shaft 11 via a mounting portion 23 and a stator iron core 16 for rotationally driving the rotor iron core 13 are sealed in a motor frame 18 is shown in FIG. This is the same as the structure. Further, the rotor iron core 13 has an induction rotor structure having a secondary conductor and an end ring 13a, and the stator iron core 16 has a primary winding 17 to generate a rotating magnetic field that drives the rotor iron core 13 to rotate. The structure is also the same as the conventional structure shown in FIG.
[0013]
The hermetic motor is provided with a groove (space) 24 for the mounting portion 23 in the axial direction of the blower to fix the B over data iron core 13 to the spindle 11. Along with the rotation of the main shaft 11, a circulating wind that circulates from the groove 24 into the motor frame 18 is generated. On the other hand, a gap groove 25 serving as a ventilation path is provided at a joint portion between the motor frame 18 and the stator 16.
[0014]
FIGS. 2A, 2 </ b> B, and 2 </ b> C are diagrams illustrating details of the attachment portion 23 of the rotor. The mounting portion 23 includes a cylindrical member 23a fitted to the main shaft 11, a rib 23b standing in the radial direction thereof, and a cylindrical member 23c to which the rib 23b is connected. The second cylindrical member 23c is fixed to the rotor iron core 13 and supports it. Here, the rib 23b extends linearly as a whole in the radial direction, and is inclined (rotated) in the circumferential direction with respect to the rotation axis as shown in the development view of (c) in the axial direction. . And the space 24 between the rib 23b and the rib 23b becomes a groove | channel for ventilation.
[0015]
Therefore, since the mounting portion 23 rotates as the main shaft 11 rotates, the ribs 23b correspond to the blades of the impeller, thereby blowing air in the axial direction. Further, as shown in FIG. 3, the rib may be formed in a curved surface like the impeller of the blower fan. By forming the rib shape into a curved surface, the processing must be complicated, but the efficiency of blowing can be increased.
[0016]
FIG. 4 shows an example in which a ventilation groove is provided at the joint between the motor frame and the stator iron core. In this case, a clearance groove 25 through which the circulating air flows is provided on the inner peripheral surface of the motor frame 18. As shown in the drawing, a large number of grooves 25 are arranged at equal intervals in the circumferential direction on the inner peripheral surface of, for example, an aluminum material constituting the motor frame 18, and these grooves 25 are linearly arranged along the axial direction. Yes.
[0017]
FIG. 5 shows an example in which ventilation grooves are provided on the stator iron core side of the joint between the motor frame and the stator iron core. As shown in the drawing, a large number of ventilation grooves are arranged at equal intervals in the circumferential direction on the outer peripheral surface of the stator iron core 16, and these grooves are arranged linearly along the axial direction.
[0018]
FIG. 6 is a diagram showing a circulation path of the circulation wind. When the attachment portion 23 rotates with the rotation of the main shaft 11, a circulating air 30a is generated as indicated by an arrow in the figure. That is, in the mounting portion 23, the air in the chamber 28 in the motor frame 18 is sucked into the rotating air blowing groove 24, which is indicated by an arrow 30 b in the drawing, and is blown from the other side of the mounting portion 23 into the chamber 29 as the circulating air 30 a. The The circulating air 30c in the chamber 29 enters the ventilation groove 25 provided at the joint between the stator iron core 16 and the motor frame 18, flows along the ventilation groove 25, and is surrounded by the motor frame 18 as the circulating air 30d. It circulates in 28. The heat generated in the rotor iron core 13 is absorbed when passing through the air blowing groove 24, and the heat is transferred to the motor frame 18 when passing through the ventilation groove 25 between the motor frame 18 and the stator iron core 16. To do. The heat transferred to the motor frame 18 is radiated from the outer surface of the motor frame 18 to the outside air.
[0019]
FIG. 7 shows the structure of the hermetic motor according to the embodiment of the present invention, and shows an example in which fins and water cooling pipes are provided to promote heat dissipation by the motor frame. As shown in the figure, fins 30 for absorbing heat are provided on the inner peripheral surface side of the motor frame 18. The fin 30 is disposed at a position where circulating air flows through the ventilation groove 25 provided at the joint between the stator iron core 16 and the motor frame 18, and circulates to convey heat generated in the vicinity of the main shaft 11 of the rotor 13. It plays an auxiliary role for cooling the wind.
[0020]
A cooling water pipe 31 is disposed in the motor frame 18, and the cooling water circulates in the pipe 31. The cooling water pipe 31 is a stainless steel pipe, for example, and is cast into the motor frame 18 made of aluminum, for example. By flowing the cooling water through the cooling water pipe 31, the motor frame 18 is efficiently cooled, and as a result, this cooled air is conveyed to the vicinity of the main shaft by the circulating air, thereby cooling the rotor and the main shaft portion. In particular, the temperature rise in the main shaft portion is suppressed.
[0021]
FIG. 8 shows an example in which the water cooling jacket 32 is arranged together with the cooling fins 30 on the motor frame. Also in the water cooling jacket 32, the motor frame 18 is efficiently cooled in the same manner as the water cooling pipe 31 shown in FIG. 7, thereby suppressing a rise in temperature particularly in the vicinity of the main shaft.
[0022]
9 and 10 show a modification of the air blowing groove provided in the attachment portion for attaching the rotor to the main shaft. In these examples, the rotor iron core 13 is fixed to the main shaft 11. In FIG. 9, the air blowing groove 34 is provided on the rotor iron core side, and in FIG. 10, the air blowing groove 35 is provided on the main shaft 11 side. These ventilation grooves 34 and 35 are provided so as to communicate in the rotation axis direction and to rotate in the circumferential direction. For this reason, when the main shaft is rotated by the operation of the electric motor, the air blowing groove works in the same manner as the fan and generates a circulating wind.
[0023]
Also in this embodiment, the configuration of the ventilation groove provided between the motor frame and the stator iron core, the fin provided on the inner peripheral surface of the motor frame, the cooling water channel, and the like is the same as that of the above-described embodiment. In this embodiment, the example in which the rotor iron core 13 is directly fixed to the main shaft 11 has been described. Of course, a sleeve or the like may be inserted between them.
[0024]
In the above embodiment, an example of an induction motor using a squirrel-cage rotor has been described as an example of an electric motor. However, it goes without saying that the gist of the present invention can be similarly applied to other types of electric motors.
[0025]
【The invention's effect】
As described above, according to the present invention, the air in the motor frame sealed with the rotation of the rotor is blown and circulated, and in particular, the vicinity of the main shaft of the rotor is cooled. As a result, it is possible to suppress the temperature rise of the stator windings and heat transfer from the secondary conductor of the rotor to the main shaft, and as a result, the temperature rise of the main shaft can be reduced. As a result, the temperature rise of the bearing can be kept low, accidents such as a significant decrease in bearing life and seizure can be prevented, and a long-life and stable motor operation can be achieved.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a hermetic motor related to the present invention.
FIGS. 2A and 2B are views showing a structure of a mounting portion, wherein FIG. 2A is a longitudinal sectional view, FIG. 2B is a view taken along an arrow A in FIG. 2A, and FIG. FIG.
3 is a view showing a modification of the rib in FIG. 2. FIG.
FIGS. 4A and 4B are diagrams illustrating an example of a ventilation groove provided in a joint portion between a motor frame and a stator iron core, where FIG. 4A is a cross-sectional view, and FIG.
FIG. 5 is an equivalent diagram showing a modification of FIG. 4;
6 is a diagram showing a path of circulating air in the hermetic motor shown in FIG. 1. FIG.
FIG. 7 is a longitudinal sectional view of a hermetic motor according to an embodiment of the present invention , showing that a cooling fin and a water cooling pipe are provided.
FIG. 8 is a view showing a modification of FIG. 7 , and is a view showing that a cooling fin and a water cooling jacket are provided.
FIGS. 9A and 9B are diagrams showing a modification of the air blowing groove provided in the vicinity of the main shaft, wherein FIG. 9A is a longitudinal sectional view, and FIG. 9B is a transverse sectional view.
FIGS. 10A and 10B are diagrams showing another modification of the air blowing groove provided in the vicinity of the main shaft, wherein FIG. 10A is a longitudinal sectional view, and FIG. 10B is a transverse sectional view.
FIG. 11 is a longitudinal sectional view of a conventional hermetic motor.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 Main axis | shaft 13 Rotor iron core 16 Stator iron core 18 Motor frame 23 Mounting part 24, 34, 35 Air blow groove 25 Ventilation groove

Claims (5)

A rotor that is fixed to the main shaft, a stator that rotationally drives the rotor, and a bearing that rotatably supports the main shaft are sealed motors that are sealed in a motor frame ,
A gap groove for blowing air is provided on the inner peripheral surface of the mounting portion of the rotor iron core that fixes the rotor iron core to the main shaft, and air can be blown in the axial direction along the main shaft as the main shaft rotates.
A large number of gap grooves serving as ventilation paths are formed along the circumferential direction on the inner peripheral surface of the motor frame at the joint between the stator and the motor frame to which the stator is fixed, and the gap grooves extend along the axial direction. Arranged in a straight line,
A cooling water passage is disposed in the motor frame, and the cooling water circulates to cool the motor frame, and air that is blown in the axial direction along the main shaft as the main shaft rotates rotates in the motor frame. A hermetic motor, wherein the motor is cooled while passing through the ventilation path on the peripheral surface, and the air cools the rotor and the main shaft portion as circulating air . The hermetic motor according to claim 1, wherein the motor frame is made of aluminum . 2. The hermetic motor according to claim 1, wherein the cooling water channel is a water-cooled pipe, and the water-cooled pipe is cast inside the motor frame . The hermetic motor according to claim 1, wherein the cooling water channel is a water cooling jacket . Sealed motor according to claim 1, characterized in that a fin on the inner peripheral surface of the front SL motor frame.

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