JPS643846Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a sensor positioning structure for a radial magnetic bearing device that facilitates adjustment of the mounting phase of the magnetic bearing body and its control sensor around the shaft. .

[Prior Art] As is well known, radial magnetic bearings use magnetic repulsion or attraction to uniformly magnetically levitate a shaft from its surroundings and support it in a non-contact manner. It is suitable for shaft bearing devices.

This type of magnetic bearing device includes a magnetic bearing body in which electromagnets are circumferentially arranged around the shaft to provide radial magnetic buoyancy to the shaft, and a radial magnetic bearing body that detects the radial displacement of the shaft near the magnetic bearing body. Normally, a control sensor is provided to control the axis of the shaft by varying the magnetic force of the electromagnet arranged in the corresponding direction according to the detected displacement of the sensor. In order to ensure control accuracy, it is very important to completely match the arrangement phase of each electromagnet in the bearing body with the phase of the radial control sensor arranged corresponding to these electromagnets.

Conventionally, when assembling this type of magnetic bearing device, the bearing body and the control sensor are separately set at predetermined positions around the shaft, and the mutual mounting phase is adjusted. However, it is difficult to completely match the phases of the two components, and this poses a problem in that the disassembly and reassembly work is slow and there is a high risk of accidentally causing a phase shift.

[Problems to be solved by the invention] Focusing on these circumstances, the present invention aims to simplify the phase alignment between the magnetic bearing body and the radial control sensor in this type of magnetic bearing device by devising the mounting structure of both. This is to ensure that it can be done.

[Means for Solving the Problems] That is, in the radial magnetic bearing device described above, the present invention includes a pin guide on one side of a sensor holder that holds the magnetic bearing body and the radial control sensor, and a pin guide on the other side. In addition to providing pins, these pins are fitted into pin guides to align the phases.
It is characterized in that the two are connected and connected so that they cannot rotate relative to each other.

[Function] With this type of structure, as long as the pins and pin guides are positioned accurately in advance, the sensor holder can be aligned with the magnetic bearing body, and both pins and pin guides can be aligned. Installation is completed by simply connecting and connecting them so that they fit together, and each electromagnet on the main body side and each sensor on the holder side can be accurately aligned in phase without error.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 shows, as an example, a case where the present invention is implemented in a magnetic bearing device that pivotally supports a rotor shaft of a turbo-molecular pump.

Therefore, first, the illustrated pump configuration will be briefly explained.
A turbo molecular pump has a turbine blade row T that operates an axial flow turbo mechanism by alternately arranging rotor blades and stator blades in a space surrounded by an upper outer frame case C.
A rotor chamber R (partially not shown) is provided in which the rotor blades are arranged in a rotor chamber R (partially not shown), and built-in motors ms and mr for rotationally driving a rotor shaft S that rotates the rotor blades at high speed are installed in the lower motor housing H and the shaft S. The machine room M is provided with a magnetic bearing device for non-contactly supporting the machine. and,
This turbo-molecular pump is capable of achieving an ultra-high vacuum by taking in gas molecules from its intake port s and discharging them from its exhaust port p by the mechanical evacuation action of the turbine blade row T.

Next, the overall configuration of the magnetic bearing device that pivotally supports the rotor shaft S of this turbo molecular pump will be explained. This bearing device includes an upper radial magnetic bearing device 1, a lower radial magnetic bearing device 2, and a thrust magnetic bearing device 3. These 3
The shaft S is supported by a bearing device so that it can be controlled on five axes. That is, each of the upper and lower radial magnetic bearing devices 1 and 2 includes a magnetic bearing body 4 in which four electromagnets 6, 6... that provide radial magnetic buoyancy to the shaft S are arranged at equiangular intervals in the circumferential direction around the shaft S, 4, and radial control sensors 5, 5... which detect the radial displacement of the shaft S near the top and bottom of the main bodies 4, 4 and are arranged around the shaft S in a number corresponding to the electromagnets 6, 6... at equal angular intervals. It consists of. In addition, the thrust magnetic bearing device 3 includes electromagnets 9, 9 that are arranged opposite to each other to apply axial magnetic buoyancy to a thrust ring 10 that is detachably connected to the shaft end of the shaft S.
a magnetic bearing body 7 which closely holds the magnetic bearing body 7 from above and below;
The thrust control sensor 8 is arranged opposite to the end of the shaft S and detects the axial displacement of the shaft S. The radial magnetic bearing devices 1 and 2 have their control sensors 5 and 5, respectively.
The magnetic buoyancy of the electromagnets 6, 6 of the main body 4 can be varied according to the radial displacement detected by the thrust magnetic bearing device 3, and the magnetic buoyancy of the electromagnets 9, 6 of the main body 7 can be varied according to the axial displacement detected by the control sensor 8. 9's magnetic buoyancy can be varied, making it possible to control the shaft support position of the shaft S in a total of five axes, two radial axes around the shaft S and one axial axis at the end of the shaft. . In FIG. 1, reference numerals 11 and 12 indicate touch bearings that directly support the shaft S when no magnetic buoyancy acts on it.

In this overall configuration, the radial magnetic bearing devices 1, 2 are arranged so that the phases of the electromagnets 6, 6... of the main body 4 and the control sensors 5, 5... are matched in the following manner. ing. The magnetic bearing main body 4 is made up of a ring-shaped base 4a in which electromagnets 6, 6, .
is fitted into the inner periphery of the motor housing H to be positioned and fixed, while each control sensor 5, 5... is attached to the inner periphery of a ring-shaped sensor holder 13 with an L-shaped cross section, and is fitted onto the inner periphery of the motor housing H. It is held and positioned by the sensor holder 13 into which it is fitted. The magnetic bearing body 4 and the sensor holder 13 are concentrically abutted and connected in the motor housing H, and as shown in FIG. A pin 14 is provided on the former and a pin guide 15 is provided on the latter on the base 4a of the sensor holder 13 and the support cylinder 13a of the sensor holder 13, and the pin 14 is fitted into the pin guide 15 to match the phase of the two and to prevent relative rotation. I'm trying to match it.

In addition, in the embodiment shown in FIG. 1, the base 4a of the magnetic bearing body 4 and the motor housing H are also pin-engaged (pin 16), and the upper sensor holder 13 and the presser plate 17 that abuts this are also engaged. are also pin-engaged (pin 18) for assembly.

If the structure is as described above, the phase position of the pin 14 provided on the magnetic bearing body 4 side and the pin guide 15 provided on the sensor holder 13 side is adjusted in advance.
As long as each electromagnet 6, 6... and control sensor 5, 5... are positioned accurately according to the arrangement phase,
When assembling it, all the installation work is completed by simply connecting the sensor holder 13 to the magnetic bearing main body 4 so that the pins 14 and pin guides 15 of both are fitted, and the entire installation work is completed. As a result, the phases of the electromagnets 6, 6, . . . on the main body 4 side and the sensors 5, 5, . Therefore, with such a structure, the disassembly and assembly of the magnetic bearing device is very easy, and the electromagnets 6, 6, .
There is no longer any difficulty in phase alignment between the sensor and the sensors 5, 5, . . . on the holder 13 side.

Note that the number of pairs of pins 14 and pin guides 15 provided for phase alignment may be one or more. Further, contrary to the embodiment, the pin guide 15 may be provided on the main body 4 side, and the pin 14 may be provided protruding from the sensor holder 13 side.

As an example, the case where the present invention is applied to a radial magnetic bearing device that pivotally supports the rotor shaft of a turbo-molecular pump has been described above, but it goes without saying that the present invention is not limited in its application to this type of use. .

[Effects of the invention] The invention has the above configuration, and
It has been possible to provide a suitable sensor positioning structure that allows easy and reliable phase alignment of the electromagnet and control sensor in a radial magnetic bearing device.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a magnetic bearing device for a turbo-molecular pump showing an embodiment of the present invention. Figure 2 is the first
FIG. S... Shaft, 1, 2... Radial magnetic bearing device, 4... Magnetic bearing main body, 4a... Magnetic bearing main body base, 5... Radial control sensor, 6, 6... Electromagnet,
13...Sensor holder, 13a...Sensor holder support cylinder part, 14...Pin, 15...Pin guide.

Claims (1)

[Scope of utility model registration request] A radial magnetic bearing device comprising: a magnetic bearing body in which electromagnets that provide radial magnetic buoyancy to the shaft are circumferentially arranged around the shaft; and a radial control sensor that detects radial displacement of the shaft near the magnetic bearing body. In this method, a pin guide is provided on one side of a sensor holder that holds the magnetic bearing body and the radial control sensor, and a pin is provided on the other side, and these pins are fitted into the pin guide to align the phases, and the relative rotation of the two is achieved. A sensor positioning structure for a radial magnetic bearing device, characterized in that the sensor is connected in an irreversibly abutting manner.