JPH06141509A - Rotating machine - Google Patents

Abstract

PURPOSE:To increase a cooling effect by making a space in the circumferential direction of an inner cylinder of a bearing that supports a hollow shaft between the hollow shaft made of material having a different thermal conductivity from that of a shaft and a fitting section of the inner cylinder of the bearing. CONSTITUTION:In a rotating machine, a space (a) is formed in the circumferential direction of an inner cylinder of a bearing that supports a hollow shaft 7a between the hollow shaft 7a made of material having a different thermal conductivity from that of a shaft 7 and a fitting section of the inner cylinder of the bearing. Heat generated due to a loss in the rotating machine is emitted from the surface of a bracket that is brought into contact with the bearing through the shaft 7a and then through a fan and the bearing. The shaft 7 and the shaft 7a are fit in with each other by shrinkage fit and so, the heat generated in the rotating machine is transmitted to the shaft 7a of a higher thermal conductivity through the shaft 7 and then the temperature of the shaft 7a increases. However, cooling air passes through a ventilation channel (b) and therefore the heat radiation is accelerated. Meanwhile, the space (a) cuts off heat and thereby the heat transmission to the bearing is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to cooling a rotating machine.

[0002]

2. Description of the Related Art A conventional rotating machine will be described with reference to FIGS. FIG. 5 is an overall configuration diagram showing a cross section of the rotating machine.
Is a partial configuration diagram showing a cross section of the rotating machine, and FIG. 7 is a partially enlarged view of FIG. 6. In the figure, 1 is a frame, 2 is a stator,
3 is a winding attached to the stator 2, 4 is a rotor mounted on the shaft 7, 5 is a bracket, 6 is a bearing housed in the bracket 5, 8 is a fan fitted to the shaft 7, and 9 is a fan. A cover 10 for protecting 8 is an arrow showing a heat conduction path. A is a gap generated between the frame 1 and the stator 2.

Next, the operation of the rotating machine will be described.
Now, when the rotating machine is operating, the rotating machine causes losses such as copper loss and iron loss, and the temperature of the rotor 7 and the like rises. The loss generated in the rotor 7 becomes heat and is dissipated through the surface of the frame 1, the surface of the bracket 5 and the shaft 7, and the heat transferred to the stator 2 is transferred to the frame 1 and to the outside air. Dissipated. Further, the cooling air from the fan 8 promotes cooling of the surface of the frame and the bracket.

[0004]

As described above, since the heat generated in the rotor of the conventional rotating machine is dissipated to the outside mainly through the shaft 7, it is fitted to the shaft located on the heat dissipation passage. There is a problem that the temperature of the inner ring of the bearing rises and grease in the bearing flows out, causing the bearing to burn out. Further, since a gap A is formed in the eccentric portion due to the respective parts of the frame 1 and the stator 2, it is difficult to transfer the heat of the stator 2 to the frame 1 and the rotating machine cannot be cooled sufficiently.

The present invention has been made to solve the above problems, and an object thereof is to improve the cooling capacity of a rotating machine.

[0006]

A rotary machine according to a first aspect of the present invention includes a hollow shaft made of materials having different thermal conductivities.
A gap is provided in the circumferential direction between the fitting portions of the inner diameter side cylinder of the bearing that supports the shaft.

A rotating machine according to a second aspect of the present invention comprises a frame fixed to the outer circumference of the stator, and load side and anti-load side brackets for holding the rotor in the opening of the frame, and the inner circumference of the frame. The surface is knurled.

[0008]

In the first aspect of the invention, the shaft of the hollow shaft is ventilated in the hollow, and the air gap in the circumferential direction suppresses heat transfer.

The knurled holes formed on the frame according to the second aspect of the invention contribute to the tight connection between the stator and the frame.

[0010]

EXAMPLES Example 1. An embodiment of the present invention will be described below. FIG. 1 is a block diagram of a rotary machine that is an embodiment of the present invention. In the figure, the same reference numerals as those used in the related art indicate the same or corresponding parts. 7a is fitted on the shaft 7, and the shaft 7
A shaft having a higher thermal conductivity, a is a space provided for fitting the shaft 7 and the shaft 7a, and b is a cylindrical space of the shaft 7 and a cylindrical ventilation path of the shaft 7a. Reference numeral 11 is an arrow indicating a heat transfer path.

Next, the operation of the present invention will be described. The heat generated by the loss generated in the rotating machine is dissipated from the bracket surface in contact with the bearing via the fan or the bearing via the shaft 7, but the shaft 7 and the shaft 7a are fitted by shrink fitting or the like. The heat generated in the shaft 7a having a high thermal conductivity is transmitted through the heat transfer member and the temperature of the shaft 7a rises. However, the cooling air passes through the air passage b to promote heat dissipation. On the other hand, the space a shields heat and suppresses heat transfer to the bearing.

Example 2. FIG. 2 shows another embodiment of the present invention, in which c is a shaft 7 and a shaft 7b.
Is a ventilation passage c in which a screw-shaped groove is provided on the inner circumference of the cylindrical space. Ventilation path c makes shaft 7a more effective
Promotes heat dissipation.

Embodiment 3. FIGS. 3 and 4 show another embodiment of the present invention. In the drawings, reference numeral 21 denotes a frame in which a steel plate is formed into a tubular shape and the inner peripheral surface for fixing the stator core is knurled. . When pressing the stator 2 into the frame 1,
The peaks and valleys of the knurls on the inner peripheral surface of the frame 1 are compressed and crushed by the surface pressure of the outer peripheral surface of the stator 2. Therefore, although the inner diameter of the frame 1 and the outer diameter of the stator 2 are eccentric with respect to the true circle, the inner peripheral surface of the frame 1 and the outer peripheral surface of the stator 2 are in close contact with each other.

Example 4. By forming a steel plate into a tubular shape and knurling the inner peripheral surface that fixes the stator core, and by applying a resin or adhesive having good heat conductivity to the inner peripheral surface of the frame 1 (not shown) At the time of press-fitting the stator, resin or adhesive enters the ridges and valleys of the knurls so that the contact surface between the stator 2 and the frame 1 covers the entire outer circumference of the stator 2.

[0015]

According to the first aspect of the present invention, a hollow space is provided in the circumferential direction between the hollow shaft made of materials having different thermal conductivities and the fitting portion of the inner diameter side cylinder of the bearing supporting the shaft. Therefore, there is an effect that the cooling effect can be improved while suppressing the temperature rise of the bearing inner ring.

According to a second aspect of the present invention, a frame fixed to the outer circumference of the stator and load-side and anti-load-side brackets for holding the rotor in the opening of the frame are provided, and the inner peripheral surface of the frame has knurled eyes. Since the heat treatment is applied, the stator and the frame are brought into close contact with each other to improve the degree of coupling, so that the cooling effect can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing the structure of a rotating machine according to an embodiment of the present invention.

FIG. 2 is a sectional view showing the structure of a rotating machine according to another embodiment of the present invention.

FIG. 3 is a sectional view showing the structure of a rotating machine according to another embodiment of the present invention.

FIG. 4 is a partially enlarged view showing the structure of a rotating machine according to another embodiment of the present invention.

FIG. 5 is a sectional view showing a structure of a conventional rotating machine.

FIG. 6 is a partial configuration diagram showing a structure of a conventional rotating machine.

FIG. 7 is a partially enlarged view showing the structure of a conventional rotating machine.

[Explanation of symbols]

 1 Frame 2 Stator 12 Ventilation path 13 Ventilation path 14 Heat transfer path

Claims (2)

[Claims] 1. A rotation characterized in that a gap is provided in the circumferential direction between a hollow shaft made of materials having different thermal conductivities and a fitting portion of an inner diameter side cylinder of a bearing supporting the shaft. Machine. 2. A frame fixed to the outer circumference of a stator, load-side and anti-load-side brackets for holding the rotor in the opening of the frame, and knurling on the inner peripheral surface of the frame. A rotating machine characterized by.