JPS6032536A - Internal pressure regulator for liquid ring motors - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid-sealed electric motor in which the vicinity of a stator is sealed by a can.

Conventionally, there is a liquid ring type electric motor of this type as shown in FIG. 1, for example.

That is, one end opening is closed by a bellows 1 to adjust the pressure difference between the inside and outside liquid to zero. Inside the outside v2, there is a rotor 4 fixed to the motor shaft 3 and a non-magnetic material such as stainless steel. A stator 6 sealed in a cylindrical can 5 is disposed. Motor shaft 3 is thrust bearing 1
It is held by a two-part bracket (8) and a lower bracket (9).It is supported by a shear bearing (10) on the outer shell (2).

A flange 11 whose middle part is caulked into a slot formed in the stator 6 and whose both ends are fixed to the outer shell 2.
and a holder 1 that holds a power supply device 12 that supplies power to the stator 6.
3 to form a densely packed state, the inside of which is filled with air or resin.

With this configuration, the rotor side is filled with liquid, so the cooling performance is relatively good, but the rotor side is filled with air or resin, which has low thermal conductivity due to its insulation properties. Cooling properties in these heat transfer materials #! (It is hard to say that it is good.

For this reason, it may be possible to apply a configuration in which the stator side is also filled with a liquid such as insulating oil to achieve relatively good cooling performance, but the volumetric expansion coefficient of liquid is also higher than that of solids such as resin. Furthermore, the bulk modulus of liquid is much larger than that of air, so the temperature rise due to heat generation due to iron loss, copper loss, etc., internal pressure is high, and various factors such as canning etc. There was a risk of destruction.

The present invention has been made in view of the above points, and an object of the present invention is to prevent destruction of various elements such as the can by relieving the internal pressure even when the stator side is filled with liquid.

That is, in the first aspect of the present invention, in a liquid-ring electric motor in which the inside of the outer shell is hermetically defined by a cylindrical can into a rotor side space and a stator side space, the cylindrical can and the outer shell are sealed. The above object is achieved by closing at least one end of the cylindrical space formed by the shell with a freely expandable member.

In a second aspect of the present invention, in a liquid ring electric motor in which the inside of the outer shell is defined in a cylindrical raw state, at least one end of the cylindrical space formed by the cylindrical can and the outer shell is free to expand and contract. By connecting the member to the circumferential end surface of the can, the above object is achieved, and the thermal stress of the can is also alleviated, further increasing the safety of the can. It will be done.

Hereinafter, one embodiment of each of the first invention and the second invention will be described based on FIGS. 2 to 5. Incidentally, the same elements as those in the conventional example are given the same reference numerals and the explanation thereof will be omitted.

In FIGS. 2 and 3 showing one embodiment of the first invention,
21 is a substantially cylindrical bellows whose open end surfaces of the inner and outer walls are fixed to the flange 11, and communicates with the space of the rotor 411+.
Due to the difference between the pressure of the liquid introduced into the interior through the plurality of pressure holes 22 formed in the stator 6τ (mouth space) and the pressure of the liquid such as insulating oil in the mouth space, the stator expands and contracts. Adjust the pressures to be approximately the same.

In this configuration, when the liquid in the space on the stator 6 side expands due to temperature rise due to heat generation such as iron loss and copper loss, the rotor 4
Bellows 2 until balanced with the liquid pressure in the side space.
1 is contracted, and the inside and outside of can 5 are adjusted to approximately the same pressure.
Furthermore, the pressure on the bellows 1 and outside the outer shell 2 is approximately the same. This can prevent damage to each element such as the can 5 and the outer shell 2 due to external and internal pressure, and the stator 6 f, ll
This can prevent short-circuit accidents caused by conductive liquid entering the device. Further, even when the pressure outside the outer shell 2 or the pressure in the space on the rotor 4 side or both increases, the bellows 1° 21 equalizes the pressure, so the same effect as described above occurs.

In addition, since the pressure in the space on the stator 6 side is not directly balanced with the external pressure of the outer shell 2 via the bellows 21, even if the bellows 21 is damaged, the liquid outside the outer shell 2 (normal This prevents water from entering the space on the stator 6 side, thereby preventing short-circuit accidents and improving reliability. In addition, pressure fluctuations can be controlled by pressure hole 2.
It also has the advantage of being quickly attenuated by the liquid flowing through the two parts.

Next, in FIGS. 4 and 5 showing an embodiment of the second invention, 31 is fixed to the collar 11 at the open end surface of the outer wall, and connected and fixed to the lower circumferential end of the can 5 with the open end surface 1111 of the inner wall. It is a roughly cylindrical bellows that expands and contracts in response to the difference between the pressure of the liquid in the space on the rotor 4 side and the pressure of liquid such as insulating oil in the space on the stator 6 side. Adjust to the same level.

With this configuration, as in the first embodiment of the first invention, the pressure in the space on the stator 6 side can be adjusted to a balanced state with the pressure in the space of the rotor 4 (11 tl), and the opening peripheral end surface of the can 5 can be is elastically supported by the bellows 31, it is possible to absorb forced displacement in the axial direction of the can 5 due to differences in linear expansion coefficients of the outer shell 2, the iron core of the stator 6, the can 5, etc. 5 thermal stress can be alleviated.

Therefore, in addition to the main effects of one embodiment of the first invention,
Furthermore, it has the following effects. In other words, outside of each element such as Can 5, etc.
The thermal stress acting on the can 5 can also be alleviated by the bellows 31, which relieves stress due to internal pressure, even if a special thermal stress relaxation mechanism is provided to the can 5, and the structure of the can 5 is simplified.

As explained above, the first invention and the second invention provide a liquid ring electric motor in which the inside of the outer shell is sealed into a rotor side space and a stator side space by a cylindrical can. , because the common element is a configuration in which at least one end of the cylindrical space formed by the cylindrical can and the outer shell is closed with a freely expandable member, so that both provide cooling performance in the space on the stator side. Even when filled with a liquid that can improve the speed, the pressure in the stator side space can be adjusted to balance with the pressure in the rotor side space etc. with a compact configuration, and stress on various elements such as the can can be alleviated. Furthermore, since neither of them is configured to directly balance the pressure outside the outer shell, even if the freely expandable member is damaged, the liquid outside the outer shell may often enter the stator side space. This makes it possible to prevent stator short-circuit accidents and the like, thereby improving reliability.

Moreover, since the second invention further includes a configuration in which the freely expandable member and the peripheral end surface of the can are connected, the thermal stress of the can can also be alleviated, and the can can be given special features. The safety of the can can be further increased with a simple can configuration without the need for a thermal stress relaxation mechanism.

[Brief explanation of drawings]

FIG. 1 is a half-sectional view of a conventional liquid-sealed electric motor, and FIG. FIGS. 4 and 5 are a sectional view of a main part of a liquid ring type electric motor and a half sectional perspective view of a bellows part, showing an embodiment of the second invention. 2... Outer shell 3... Motor shaft 4... Rotor 5.
...Can 6...Stator 11...Tsuba 21...
・Bellows 22...Pressure hole 31...Herose agent Masuo Oiwa (#-1 or 2 people) Fig. 1 □□□ Possible Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 1 Li b3

Claims (2)

[Claims] (1) In a liquid-ring electric motor in which a cylindrical can sealingly defines the inside of an outer shell into a rotor side space and a stator side space, the inner shell is formed by the cylindrical can and the outer shell. 1. An internal pressure regulating device for a liquid-sealed electric motor, characterized in that at least one end of a cylindrical space is closed with a freely expandable member. (2) In a liquid ring type electric motor in which the inside of the outer shell is hermetically defined by a cylindrical can into a rotor side space and a stator side space, the inner shell is formed by the cylindrical can and the outer shell. 1. An internal pressure regulating device for a liquid-sealed electric motor, characterized in that at least one end of a cylindrical space is closed by a freely expandable member, and the member is connected to a peripheral end surface of a can.