JPH036142Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an air bearing type phono motor used in a record player, and more particularly to a phono motor in which a rotor is supported in a housing in a non-contact manner by an air bearing.

Generally, the shaft of a phono motor that drives the turntable of a record player is rotatably supported by a bearing mounted on a housing, so rotational vibrations are generated inside and outside the motor. Rotational vibrations caused by the motor itself include, for example, rotational vibrations caused by uneven rotation of the rotor due to wear of bearings or shafts due to deterioration of bearing oil, and rotational vibrations caused by external parts of the motor, such as vibrations transmitted from the outside to the housing. There is rotational vibration caused by vibrations transmitted directly to the shaft via the bearings.

However, especially in phono motors, rotational vibrations significantly degrade the quality of the reproduced sound, and in order to improve the quality of reproduced sounds in audio equipment, it is necessary to reduce the rotational vibrations of the phono motors in particular to suppress the transmission of rotational vibrations. , it is required to drive the turntable in stable rotation.

This invention was made in view of the above points, and the purpose is to eliminate the rotational vibration of the phono motor.
In order to achieve this objective, the present invention includes: an inner surface of a peripheral wall of a housing that accommodates the rotor; and an inner surface of both end plates that close both open ends of the housing;
Support gaps are formed between the inner surface of the peripheral wall of the housing and the inner surfaces of the end plates and the outer peripheral surface and both end surfaces of the rotor, respectively, and compressed air is introduced into these support gaps to form an air bearing. forming and supporting the rotor in a non-contact manner,
A support gap is provided between the inner surface of the both end plates and the opposite end surfaces of the housing, along the entire outer periphery of the supporting gap between the inner surface of the both end plates and the opposite end surfaces of the rotor. The present invention provides an air bearing type phono motor characterized in that a larger exhaust gap is provided, and compressed air is introduced into each of the support gap through an enlarged space opening in each of the support gap.

An embodiment of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 shows a longitudinal cross-sectional view of an air bearing type phono motor to which the present invention is applied. 9 and
It consists of a stator 10, a rotor 15, etc., which are housed in the housings 2, 2'. The housing 2 has a cylindrical shape, and its inner diameter is a large diameter part 2a and a small diameter part 2 extending from the approximate center to an open end on one side and an open end on the other side, respectively.
A first cylindrical body 3 is fitted inside the small diameter portion 2b, and a second cylindrical body 4 thinner than the first cylindrical body 3 is fitted inside this cylindrical body 3. ing.

As shown in FIGS. 1 and 2, an annular groove 2c is formed on the inner circumferential surface of the small diameter portion 2b of the housing 2 at the approximate center thereof, and one end of the side wall opens at the bottom of the annular groove 2c, and the other end opens at the bottom of the annular groove 2c. A hole 2d opening on the outer circumferential surface is bored in the radial direction. Further, a hole 2e is formed in the side wall of the housing 2, with one end opening to the large diameter portion 2a and the other end opening to the outer circumferential surface, and the end surface 2f has a plurality of holes 2g at equal intervals in the circumferential direction, for example. Three holes are drilled in the axial direction, and a screw hole 2h is bored in the axis of the bottom of each of these holes 2g.

An annular groove 3a facing the annular groove 2c is formed on the outer circumferential surface of the first cylindrical body 3. At the bottom of the annular groove 3a, one end is formed at equal intervals in the circumferential direction. A plurality of holes 3b, for example four, are bored in the radial direction, and the other end is open to the inner circumferential surface. In the second cylinder 4, holes 4a having a larger diameter than the holes 3b (hereinafter referred to as enlarged spaces) are aligned and bored at locations corresponding to the holes 3b of the cylinder 3. Thus, each enlarged space 4a corresponds to each hole 3 of the second cylindrical body 3.
b, communicates with the hole 2d via the annular groove 3a and the annular groove 2c of the housing 2.

Housing 2', cylinders 3' and 4' are also housing 2,
It is constructed in the same manner as the cylindrical bodies 3 and 4, and the same or corresponding parts as those of the housing 2 and the cylindrical bodies 3 and 4 are given the same or corresponding numerals, and the explanation thereof will be omitted.

The stator 10 around which the excitation coil 11 is wound is
One end from the center is fitted into the large diameter part 2a of the housing 2, and the other end from the center is fitted into the large diameter part 2a' of the housing 2', as shown in the figure. Each housing 2 and 2' is firmly fastened with a plurality of bolts 12 to form one housing 5 and house a stator 10 therein. The coil 11 of the stator 10 is connected to a connection terminal (not shown) fixed to a predetermined location on the outer wall of the housing 2.

The end plate 6 consists of an annular disk 7 and a disk 8 fitted inside the disk 7. The outer diameter of the annular disk 7 is the same as the outer diameter of the housing 2, and the inner diameter is the same as the outer diameter of the housing 2. It has approximately the same shape as the inner diameter of No. 2. A hole 7a is bored in the side of the disk 7 in the radial direction, with one end opening on the inner circumferential surface and the other end opening on the outer circumferential surface. An annular groove 8a extending in the circumferential direction is formed on the outer circumferential surface of the disk 8 that is in contact with the inner circumferential surface of the disk 7, and a hole 8b whose one end opens into the bottom of the groove 8a is formed at the bottom of the annular groove 8a. A plurality of holes, for example four, are bored at equal intervals in the circumferential direction.

On the other hand, four recesses (hereinafter referred to as enlarged spaces) 8d are formed on the same circumference in the circumferential direction on the inner surface 8c at positions corresponding to the other ends of the respective holes 8b.
The hole 8 is located at the center of the bottom of each of these enlarged spaces 8d.
A hole 8e communicating with the other end of b is bored.
Thus, each enlarged space 8d communicates with the hole 7a via the holes 8e, 8b and the annular groove 8a. Also, disk 7
A hole 7b is formed in the inner surface of the housing 2, facing each hole 2g of the housing 2, and a bolt hole 7c is formed in the center of the bottom of each of these holes 2g. The housing 2 and the end plate 6 are screwed together with bolts 23 through springs 21 interposed in each hole 2g of the housing 2 and each hole 7b of the end plate 6 with a predetermined exhaust gap 32 to be described later. Ru.

The end plate 9 has the same diameter as the outer diameter of the housing 2',
A recess (hereinafter referred to as an enlarged space) 9b is formed at the center of the inner surface 9a, and a hole 9c is bored at the center of the bottom of this enlarged space 9b, with one end on the outer peripheral surface and the other end on the side. A hole 9d opening into the hole 9c is bored in the radial direction.

A hole 9e is formed in the inner surface 9a of the end plate 9, facing the hole 2g' of the housing 2', and a bolt hole 9f is formed in the center of the bottom of the hole 9e. The housing 2' and the end plate 9 are provided with a predetermined exhaust gap 32', which will be described later, by a bolt 24 via a spring 22 interposed in each hole 2g' of the housing 2' and each hole 9e of the end plate 9. It is screwed on.

The rotor 15 has a substantially cylindrical shape, and the ends of rotors 17 and 18 for air bearings are fitted into both ends of an annular rotor 16 for a motor.
A bolt 17a drilled in the center of the end face of the rotor 1
8 into the screw hole 18a formed in the rotor 1.
6, 17, and 18 are integrally formed. The length of this rotor 15, that is, from the end surface 17b to the end surface 18b
The length from the end surface 2f of the housing 2 to the end surface 2f' of the housing 2' is set to be longer by a predetermined dimension. The rotors 16 to 18 have the same outer diameter, and the outer diameter is slightly smaller than the inner diameter of each cylindrical body 4, 4' of the housing 2, 2'. 17,18
The support gap 30, 30' between the outer circumferential surface of the support gap 30 and 30' is set to, for example, about 20 to 30 microns. Furthermore, the first
In the figures and FIG. 2, the gap 30 is exaggerated for clarity.

One end of an output shaft (hereinafter referred to as shaft) 19 is press-fitted and fixed to the axial center position of the rotor 17, and the other end passes loosely through the shaft hole 8f of the end plate 6 with a slight gap to the outside of the housing 2. It stands out. A motor rotor 16 is made of a magnetic member, and the rotor 10, the stator 10, and the coil 11 constitute, for example, a hysteresis synchronous motor. In addition, rotor 1 for air bearing
7 and 18 are made of non-magnetic material such as brass material. Each end surface 17b, 18b of the rotor 15,
The supporting gaps 31, 31' between the opposing inner surfaces 6a, 9a of the end plates 6, 9 are set, for example, to about 20 to 30μ, and these gaps 31, 3
1' is adjusted by bolts 23 and 24 screwing together the housing 2 and the end plate 6, and the housing 2' and the end plate 9. Since the length between the end surfaces 2f, 2f' of the housings 2, 2' is shorter than the length between the end surfaces 17b, 18b of the rotor 15, the end surfaces 2f, 2f' of the housings 2, 2' and the end plates 6, 9 The exhaust gap 32, 32' between the inner surface 6a, 9a of the support gap 31, 31' is larger than the support gap 31, 31'. Therefore, the support gaps 31, 31' that support the rotor 15 are sufficiently small and the pressure of the compressed air within the gap is sufficiently high to support the rotor 15 in suspension. The compressed air is passed through the relatively large surrounding exhaust gap 32,3.
2', the fluid can be discharged smoothly with little flow resistance and without turbulence. Moreover, the exhaust gap 32, 32' is replaced by the support gap 31,
It is provided in an annular shape along the entire outer circumference of 31',
Therefore, the compressed air in the support gap 31, 31' is discharged uniformly over the entire circumference, and the rotors 17, 18 can be evenly supported in the axial direction.

The open ends of the holes 2d, 2d' in the housings 2, 2' and the holes 7a, 9d in the end plates 6, 9 are connected to an air compressor (none of which is shown) via fittings and piping, respectively. Supply specified compressed air. Further, the coil 11 of the stator 10 is connected to a predetermined power source.

In this configuration, the compressed air supplied to the hole 2d of the housing 2 is introduced into each enlarged space 4a through the annular grooves 2c and 3a and each hole 3b communicating with the annular groove 3a, and the inner circumference of the cylinder 4 is Surface and rotor 1
introduced into the gap 30 between the outer peripheral surface of the
The entire circumferential surface of the rotor 17 is pressed uniformly and the gas is discharged to the outside of the housing 2 through the gap 32 between the end plate 6 and the end surface 2f of the housing 2 and the hole 2e of the housing 2.

Similarly, the compressed air supplied to the hole 2d' of the housing 2' is transferred to the annular grooves 2c', 3a' and the annular groove 3.
It is introduced into each enlarged space 4a' through each hole 3b' communicating with The entire circumferential surface of the housing 2' is pressed uniformly and the gas is discharged to the outside of the housing 2' through the gap 32' between the end plate 9 and the housing 2' and the hole 2e' in the housing 2'. As a result, an air bearing is formed between the outer peripheral surface of the rotor 15 and the enlarged spaces 4, 4'.
The rotor 15 is supported by the air bearing at the center of the enlarged spaces 4, 4' with a gap of 20 to 30 microns.

Further, the compressed air supplied to the holes 7a of the end plate 6 is introduced into each enlarged space 8d via the annular groove 8a and each hole 8e, and the compressed air is introduced into each enlarged space 8d through the annular groove 8a and each hole 8e.
The rotor 15 is introduced into the gap 31 between the end plate 6
and the end face 2f of the housing 2.
The liquid is smoothly discharged from the housing 2 to the outside of the housing 2. Similarly, compressed air supplied from the hole 9d of the end plate 9 is introduced into the enlarged space 9b through the hole 9c, and into the gap 31' between the inner surface 9a of the end plate 9 and the end surface 18b of the rotor 18. introduced, the rotor 15
All end faces of the housing 2' are pressed uniformly to smoothly discharge the housing 2' from the gap 32' between the end plate 9 and the end face 2f' of the housing 2'. As a result,
Air bearings are formed between the end surfaces 17b, 18b of the rotor 15 and the end plates 6, 9, and the rotor 15
are supported by the air bearings between the end plates 6 and 9 with a gap of 20 to 30 microns, respectively.

As mentioned above, the supporting gap 30, 30',
31, 31' have enlarged spaces 4a, 4a', 8d,
Since compressed air is introduced through the gap 9b, the compressed air in the gap acts as static pressure on the rotor 15, and the rotor 15 is stably supported. That is, compressed air from the narrow holes 3b, 3b', 8b, and 9c is introduced into the expanded spaces 4a, 4a', 8d, and 9b, respectively, and the flow velocity is significantly reduced in the expanded spaces, causing the compressed air from the air compressor to decrease. The air pulsations are removed and static pressure is applied to the opposing surfaces of the rotor to provide stable, turbulent-free support pressure, and the rotor is stably supported.

If the rotor 15 is displaced in the circumferential direction within the housing 5, for example in the direction of arrow A in FIG. becomes narrower, and as a result, the air pressure in that gap becomes higher than the air pressure in the opposite gap, and the pressure difference causes the rotor 15 to return to its original center position.

Also, when the rotor 15 moves toward the end plate 6 or 9 in the axial direction, the end faces 17b and 18b are
It returns to its original position due to the pressure difference it receives.

Thus, the rotor 15 is connected to the housings 2 and 2'.
The coils 11 of the stator 10 are rotatably supported in a non-contact manner, that is, suspended in the housing, by an air bearing formed by compressed air.
rotates according to the power supplied to it. Therefore, even if vibration or the like is applied to the housing, the rotor 15 always rotates smoothly without being affected by it.

As explained above, according to the present invention, the inner surface of the peripheral wall of the housing that houses the rotor, the inner surface of both end plates that close both open ends of the housing, and the inner surface of the peripheral wall of the housing and the both end plates. supporting gaps 30, 30' between the inner surface of the rotor and the opposing outer circumferential surface and both end surfaces of the rotor;
31 and 31', compressed air is introduced into these supporting gap to form an air bearing, and the rotor is supported in a non-contact manner. a supporting gap 31 between the inner surface of the end plate and the opposite end surface of the rotor;
Exhaust gap 32, 32' larger than the gap is provided along the entire outer circumference of 31', and compressed air is introduced into each support gap 30, 30', 31, 31' through an opening in each support gap. By doing so through the expanded spaces 4a, 4a', 8d, and 9b, not only can rotational vibrations of the rotor be removed, but also the entire end surfaces of the rotor can be uniformly and stably supported by sufficient air pressure. can,
Furthermore, since pulsation from the air compressor is removed and the rotor is supported by compressed air under static pressure, highly stable support of the rotor can be obtained. Moreover, since no mechanical bearings are used between the rotor shaft and the housing, there are no wear parts, and there is no need to apply lubricating oil or replace bearings, making maintenance easier and reducing costs. It becomes possible.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view showing an embodiment of the air bearing type phono motor according to the present invention, and Fig.
It is a sectional view taken along the arrow line in the figure. 2, 2'... Housing, 3, 3'... Cylindrical body,
6, 9... End plate, 16... Motor rotor, 1
7, 18... Rotor for air bearing, 30, 3
0', 31, 31'... Support gap, 32, 3
2'...Exhaust gap, 4a, 4a', 8d, 9
b... Expansion space.

Claims (1)

[Scope of utility model registration request] The inner surface of the peripheral wall of the housing that accommodates the rotor and the inner surface of both end plates that close both open ends of the housing, and the outer peripheral surface and both end surfaces of the rotor that are opposite to the inner surface of the peripheral wall of the housing and the inner surfaces of the both end plates. Supporting gap 30, 30', 31,
31', and compressed air is introduced into these supporting gap to form an air bearing to support the rotor in a non-contact manner. In between, supporting gaps 31, 31' are provided between the inner surfaces of the end plates and the opposing end surfaces of the rotor.
Exhaust gap 32, 32', which is larger than the gap and opens directly into the outer circumferential surface of the housing, is provided along the entire outer periphery of the support gap 3.
0, 30', 31, and 31' are introduced into expanded spaces 4a and 4 that open to each of the supporting gap.
An air bearing type phono motor characterized in that the air bearing type phono motor is operated via a', 8d, and 9b.