JPS58116040A - Bearing unit for rotary electric machine - Google Patents

Abstract

PURPOSE:To prevent a bearing from rising at its temperature by forming the end of a rotational shaft at the downstream side of wind in a hollow shape opened at the end and forming a hole which communicates with the hole of the end of the shaft at the inside outer periphery of the bearing part, thereby supplying atmospheric air fed from the hole into a rotary electric machine to the periphery of the bearing. CONSTITUTION:A rotational shaft 8 of the part of a bearing 3 at the downstream side of wind of a rotary electric machine for ventilating and cooling the interior by a fan 5 is formed in a hollow shape opened at an inlet at the end, and a plurality of air inlets which communicate with the inlet are formed at the outer periphery of the shaft 8 of the inside of the bearing 3, thereby forming a shaft cooling duct. In this manner, atmospheric air is introduced due to the pressure difference between the inlet opened at the hollow shaft end and the inlet opened at the machine to the periphery of the bearing 3, thereby cooling the bearing 3 and breaking the thermal influence to the bearing 3 with the heated cooling air of a stator 7.

Description

[Detailed description of the invention] 1) Technical field The present invention relates to a bearing device for a rotating electric machine.

b) Description of Prior Art FIG. 1 shows the bearing structure of a conventional rotating electric machine. A bearing 3 housed in a housing 2 is fitted onto the central rotor shaft 1, and the outside of the machine is sealed with an end cover 4.

A fan 5 is provided inside the machine, and cooling air that has passed through the rotor 6 and stator 7 is discharged to the outside.

The flow of cooling air is shown in Figure 1 by arrows (→). In a rotating electric machine configured in this way, the cooling air takes heat from the rotor 6 and stator 70, so the temperature of the bearing increases due to the warm air flowing near the pointed bearing and heat transfer to the rotor. is bringing about.

In the past, the rise in temperature of the bearing due to these effects was almost negligible, but with recent advances in insulation technology, the temperatures of the rotor 6 and stator 7 have been set higher, which increases the temperature of the rotor 6 and stator 7. The heat transfer of the child shaft 1 has come to have an extremely large effect on the temperature of the bearing.

For example, in H-class vehicle rotating electric machines, some cooling air has a temperature rise higher than the bearing temperature rise limit of 55°C.

If the temperature of the bearing is high, the bearing grease will soften, shortening the bearing life and causing accidents.

For this reason, the increased fan capacity increases the amount of cooling air, which lowers the temperature of the cooling air, lowers the rotor temperature, and lowers the bearing temperature. (2) However, since the increase in fan capacity is measured by increasing the fan diameter, etc., this results in an increase in the weight and size of the rotating electric machine.

It provides a bearing structure.

d) Structure of the invention FIG. 2 shows one example of a bearing device for a rotating electrical machine according to the invention.

The bearing 3 housed in the housing 2 is fitted to the hollow rotary shaft 8 with an opening at the shaft end, and the rotor shaft 8 has several radial holes drilled from the end of the housing toward the center to form a hollow portion. A bearing cooling air passage is formed by communicating with the bearing cooling air passage. FIG. 3 shows a cross-sectional view of the radial hole portion of FIG. 2.

An end cover 9 is attached to the hole in the center of the outer side of the bearing.

A fan 5 is provided inside the machine, and a rotor 6 and a stator 7'
The cooling air passing through is discharged to the outside.

・) Effect of the Invention In a rotating electrical machine having a bearing structure constructed as described above, outside air is sucked in due to the differential pressure between the inlet opening at the end of the hollow shaft and the air supply opening of the radial hole opening into the machine. Air will be supplied around the bearing from the air supply port. The flow of bearing cooling air is shown in Figures 2 and 3 by arrows (・>). Cooling air for the rotor 6 and stator 7 is indicated by (→).

The bearing cooling air (...>) taken in from the inlet cools the bearing from within the rotor shaft, and at the same time flows around the housing 2, cooling the rotor 6 and stator 7. Cuts off heat influence on the bearing 3. Also, the rotor shaft 8
Since the rotor shaft 8 is cooled, there is no heat transfer from the rotor shaft 8 to the bearing 3.

Therefore, the rise in temperature F of the bearing is low, the softening of the bearing lease is prevented, and the life is extended.

f) Other embodiments Other embodiments of the present invention are shown in FIGS. 4, 5, and 6.

The bearing cooling air is shown by >> and the rotor and stator cooling air is shown by →. Figure 4 shows a radial hole in the rotor shaft in front of the fan, and Figure 5 shows a hollow hole in the rotor shaft extending to the bottom of the bearing.This is effective when there is a problem with the strength of the rotor shaft. be.

Figure 6 shows a rotor with multiple small holes instead of a narrow rotor hole, which is effective when there is a problem with the strength of the rotor shaft or when thick hollow holes would be difficult to manufacture. . FIG. 7 shows a sectional view of Bll in FIG. 6.

g) Overall effect As described above, according to the present invention, the temperature rise in the bearing is reduced, so the softening of the bearing grease is prevented, and the life of the bearing is extended. Furthermore, since there is no need to increase the fan capacity, the fan can be made smaller, resulting in a reduction in the weight and external dimensions of the rotating electric machine.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a conventional bearing device, FIG. 2 is a sectional view of a bearing device according to the present invention, FIG. 3 is a sectional view of FIG. FIG. 6 is a diagram showing another embodiment of the present invention, and FIG. 7 is a sectional view taken along the lines 1 to 2 in FIG. 6. 1... Conventional rotor shaft 2... No-Using 3.
... Bearing 5 ... Fan 6 ... Rotor 7 ... Stator 8 ... Wind road (7317) Agent Patent attorney Noriyuki Chika (and 1 other person) Figure 1 Figure 2 Figure 3 Diagram meeting diagram 4

Claims (1)

[Claims] In the bearing part on the leeward side of a rotating electrical machine that is internally ventilated and cooled, the inlet is located at the shaft end, and the other end is located on the outer periphery of the rotating shaft on the inner side of the bearing part (center side of the rotating electrical machine) as an air supply port. An open hole is provided at the end of the rotating shaft as a bearing cooling air passage.
4111& is a bearing device for a rotating electrical machine that sucks in outside air by the differential pressure between the air passage inlet and the air supply port.