JPH06351183A - Ultrahigh-speed coreless motor - Google Patents

Abstract

PURPOSE:To reduce vibration and noise by improving heat radiation efficiency and controlling vibration to maintain stabilized ultrahigh speed rotation. CONSTITUTION:A coil holding bobbin 33 is formed with aluminum nitride having high heat conductivity and high strength characteristic by mounting a coil 34 to the external circumference of a coil holding bobbin 33 fixed on a base member 31 and rotatably providing an almost cup-shaped rotor member 35 loading a magnet 36 at the internal circumference thereof to the external circumference of the coil holding bobbin 33 in such a manner that a magnet 35 is provided opposed to the coil 34.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultra-high-speed rotating coreless motor used for driving a polygon mirror which constitutes a high-speed horizontal polarization device mounted on a laser projector, a laser pattern generator or the like.

[0002]

2. Description of the Related Art As a driving motor for a polygon mirror which constitutes a high-speed horizontal polarization device mounted on a laser projector, a laser pattern generator, etc., with the increase in speed of the device, for example, a speed of over 80,000 revolutions per minute or more. It is necessary to have characteristics that it can be driven to rotate at high speed for a long time and that it is small in size with little vibration or heat generation. An ultra-high speed coreless motor 10 used for driving a conventional polygon mirror is
Explaining with reference to FIGS. 4 and 5, a plate-shaped base member 1 having a mounting hole 1A into which a mounting screw for mounting to a device chassis or the like is screwed, and the base member 1
A motor case sealed by a housing 2 formed in a cylindrical shape with a bottom and made of aluminum that is assembled and fixed to the upper part of the motor case.

On the upper part of the motor case, there is combined a polygon mirror device 20 in which a large number of polygon mirrors 23 are accurately arranged on the circumference, which drive source is the ultrahigh speed coreless motor 10. As a high-speed horizontal polarization device.

A recess 1B for mounting the coil holding bobbin 3 is provided at the center of the base member 1. The coil holding bobbin 3 is formed of Bakelite resin, and as shown in FIG. 3, the coil 4 is formed on the upper portion of the bobbin main body 3B integrally formed with the flange 3A fitted in the recess 1B of the base member 1. Is integrally formed with a shaft portion 3C to which is attached. Also, the bobbin body 3B
A heat radiating portion 3D is largely engraved and provided inside, and a heat radiating hole 3E is provided so as to open from the heat radiating portion 3D to the tip of the shaft portion 3C. In the heat dissipation part 3D,
Cooling of the coil holding bobbin 3 is performed by supplying heat radiation air from the air supply unit 13 provided in the housing 2.

A coil 4 is attached and fixed to a coil holding bobbin 3 which is attached so that the flange portion 3A is fitted in the recessed portion 1B and is set upright on the base member 1 by the attachment screw 3F. A coil 4 formed by winding a cylindrical coil frame has an inner diameter of the coil frame substantially equal to an outer diameter of a shaft portion 3C of the coil holding bobbin 3, and a lower end portion of the coil frame is tightly fitted to the shaft portion 3C. After fitting, they are firmly attached to the coil holding bobbin 3 by bonding.

A rotor member 5 is rotatably disposed on the outer peripheral portion of the coil holding bobbin 3 by a bearing member described later. The rotor member 5 is formed in a substantially cup shape as a whole, and a magnet 6 is adhesively fixed to an inner peripheral portion of the coil 4 having a diameter slightly larger than the outer diameter of the coil 4. Of course, a slight air gap is held between the magnet 6 and the coil 4 so as not to hinder the rotation of the rotor member 5.

A bearing member for rotatably holding the rotor member 5 on the outer peripheral portion of the coil holding bobbin 3 is arranged on the outer peripheral surface side of the first bearing member 7 arranged on the upper surface side of the rotor member 5. The second bearing member 8 and the third bearing member 9 arranged on the lower surface side. Air holes 12 are provided inside the first bearing member 7, the second bearing member 8 and the third bearing member 9, respectively. These air holes 12 correspond to the rotor members 5 of the bearing members 7, 8 and 9.
It communicates with the air leakage hole opened on the surface opposite to. Therefore, the air supplied from the air supply unit 11 provided in the housing 2 passes through the air holes 12 and the bearing members 7,
It leaks from the air leak outlets opened on the peripheral surfaces of 8 and 9.

Due to the leakage of the air supplied from the air supply unit 11, an air layer is formed between the bearing members 7, 8 and 9 and the outer peripheral surface of the rotor member 5, and the air layer floats as if the rotor member 5 floats. A static pressure air bearing that rotatably holds in this state is constructed. Thus, the rotor member 5 is rotatably supported by the hydrostatic bearing,
It can rotate precisely and quietly.

A shaft hole 5A is formed at the center of the ceiling of the rotor member 5, and the mounting shaft 22 is attached to the shaft hole 5A.
By fitting A, the mirror mounting member 22 of the polygon mirror device 20 is combined with the rotor member 5, and the mounting screw 22B is tightened to be integrated. The mounting screw 2 is attached to the outer peripheral portion of the mirror mounting member 22.
A plurality of polygon mirrors 23 are attached using 2C.

A slit 21A corresponding to the polygon mirror 23 is provided in the housing 21 constituting the outer peripheral portion of the polygon mirror device 20, and the slit 21A is provided.
The semiconductor laser enters the polygon mirror device 20 via the and is reflected by the polygon mirror 23.

The ultrahigh-speed rotating coreless motor 10 which is constructed as described above and which constitutes the high-speed horizontal polarization device as a whole by combining the polygon mirror device 20 is controlled by the coil 4 attached to the outer peripheral portion of the coil holding bobbin 3. By supplying the current based on the signal, the rotor member 5 rotates at high speed by using the magnetic force generated between the coil 4 and the magnet 6 attached to the inner peripheral surface of the rotor member 5 as a drive source. By the rotation of the rotor member 5, the polygon mirror 23 also rotates at high speed via the mirror mounting member 22, and the semiconductor laser light incident from the slit 21A is scanned.

[0012]

In the conventional ultra-high speed coreless motor 10 constructed as described above, since the rotor member 5 is rotated at an ultra-high speed of 80,000 rpm or more, only the rotor bearing portion is used. A large amount of heat is generated not only by the coil 4. In response to this heat generation, as described above, the housing 2 is made of an aluminum material having a relatively high thermal conductivity, and the coil holding bobbin 3 is provided with the heat radiating portion 3D. When ultra-high speed rotation driving is performed, heat is accumulated in the motor due to a shortage of heat radiation amount with respect to heat generation amount in the motor.

For this reason, the rotor member 5 or the bearing members 7, 8 and 9 that rotatably hold the rotor member 5 thermally expand, and the gap between the static pressure air bearings gradually becomes smaller. There is a problem in that the distance between the bearing surface of each of the bearing members 7, 8 and 9 becomes 0 and the rotor member 5 cannot be rotationally driven, and a so-called motor burning phenomenon occurs.

Further, the coil holding bobbin 3 formed of Bakelite resin, which has a relatively low strength, has a problem in terms of strength if it is directly attached to the rotating portion including the rotor member 5 that rotates at a high speed. On the other hand, the third bearing member 9 that constitutes the rotating portion including the coil holding bobbin 3 and the rotor member 5 is separately attached and fixed. Therefore, it is necessary to combine the coil holding bobbin 3 and the rotating portion including the rotor member 5 with precise dimensional accuracy in order to perform the ultra-high speed rotation drive. This was extremely difficult to achieve because of the indirect assembly.

Further, the Bakelite resin forming the coil holding bobbin 3 has material characteristics such as a small elastic coefficient. Therefore, only the lower end portion of the coil holding bobbin 3
The coil supported by is vibrated by the super-high-speed rotation of the rotor member 5, but this vibration cannot be absorbed by the coil holding bobbin 3, and eventually there is a problem that the entire super-high-speed coreless motor 10 is noisy. there were.

Therefore, an object of the present invention is to provide an ultra-high speed coreless motor which improves heat dissipation efficiency and suppresses vibration, thereby maintaining stable ultra-high speed rotation and reducing vibration and noise. Proposed.

[0017]

In the ultra-high speed coreless motor according to the present invention which has achieved this object, a coil is attached to the outer peripheral portion of a coil holding bobbin fixed on a base and a magnet is attached to the inner peripheral surface. It is characterized in that a substantially cup-shaped rotor member is rotatably combined so as to cover the periphery of the coil, and the coil holding bobbin is formed of a ceramic having a high thermal conductivity.

The ultra-high speed coreless motor according to the present invention is characterized in that the ceramic forming the coil holding bobbin is aluminum nitride, and the coil holding bobbin is fixed to the base member via an elastic member. It is characterized in that it is formed so as to extend in the axial direction along the coil attached to the outer peripheral portion.

[0019]

According to the ultrahigh speed coreless motor of the present invention having the above-mentioned structure, the heat generated in the coil is quickly transferred to the coil holding bobbin by forming the coil holding bobbin with the ceramic having high thermal conductivity. The heat is dissipated from the heat dissipating portion or the housing, and heat dissipation in the motor is promoted.

Further, the ceramic forming the coil holding bobbin has a relatively high strength, and the constituent members of the rotating portion including the rotor member and the coil holding bobbin are directly assembled without interposing the base member. Therefore, the assembling accuracy of the coil holding bobbin including the coil and the rotating portion including the rotor member is improved, and even when the ultra-high speed rotational drive is performed, the generation of vibration from each component member is reduced.

Furthermore, by extending the tip of the coil holding bobbin in the axial direction and enlarging the portion for holding the coil, the coil is firmly held even when the rotor member is rotated at an ultrahigh speed. The occurrence of vibration is reduced.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the present invention will be described below in detail with reference to the drawings. The ultra-high-speed rotating coreless motor 30 of the embodiment is similar to the above-mentioned conventional example in that the laser projector,
1 shows an ultra-high-speed rotating coreless motor 30 for driving a polygon mirror, which constitutes a high-speed horizontal polarization device mounted on a laser pattern generator or the like, a plate-shaped base member 31 mounted and fixed to a device chassis or the like, and this base member 31.
A motor case hermetically sealed by a housing 32 formed in a cylindrical shape with a bottom and made of aluminum that is mounted and fixed to the upper part of the motor by an attachment screw 42 is formed. With a large number of polygon mirrors 23 on the circumference
Is combined with a polygon mirror device 20 in which is accurately arranged.

The polygon mirror device 20 is combined with the same device as the above-mentioned conventional device, and the same members are denoted by the same reference numerals, and the description of the configuration and operation thereof will be omitted. Reference numeral 24 is an air supply unit for supplying heat radiation air into the polygon mirror device 20 through the air holes 25.

A mounting hole 3 into which a mounting screw for mounting the ultra-high speed coreless motor 30 to a device chassis or the like is screwed is provided on the peripheral portion of the plate-shaped base member 31.
1A is drilled, and a mounting hole 31B for assembling a coil holding bobbin 33, which will be described later, is formed in the central portion.
Has been drilled. A locking flange portion 31b protruding in the center direction is integrally provided on the peripheral edge of the opening of the mounting hole 31B to lock the peripheral edge portion of the coil holding bobbin 33 assembled in the mounting hole 31B. The coil holding bobbin 33 is fixed to the base member 31 via an O-ring 40 made of an elastic material such as rubber.

The coil holding bobbin 33 is made of a ceramic material,
Specifically, it is formed of aluminum nitride (AlN), and as shown in FIG. 2, the mounting hole 31 of the base member 31.
Disc-shaped flange portion 33A having an outer diameter fitted to B
The shaft portion 33C to which the coil 34 is assembled is integrally formed on the upper portion of the bobbin main body portion 33B integrally formed with. A slightly thin cylindrical portion 33D is integrally connected to the upper end of the shaft portion 33C. Further, inside the bobbin main body portion 33B, a heat radiating portion 33E is largely engraved and provided, and from the heat radiating portion 33E to the shaft portion 33C.
Through the inner hole of the cylindrical portion 33D through the heat dissipation hole 33F
Is perforated. The heat dissipation portion 33E includes a housing 32.
The coil holding bobbin 33 is cooled by supplying radiating air from an air supply unit (not shown) provided in the.

By the way, aluminum nitride forming the coil holding bobbin 33 has a thermal conductivity of 0.36cal / c ^m. S
· Coil and bending strength of 5,000 Kgf / cm ^2, and the coil holding bobbin 3 of the above-mentioned conventional device.
It has high thermal conductivity and high strength material properties compared to the Bakelite resin that forms the.

A coil 34 is attached and fixed to the outer periphery of the shaft portion 33C of the coil holding bobbin 33 constructed as described above. The coil 34 formed by winding a cylindrical coil frame has an inner diameter of the coil frame substantially equal to the outer diameter of the shaft portion 33C of the coil holding bobbin 33, and its axial length is the axis of the coil holding bobbin 33. Part 33C and cylindrical part 3
It is almost equal to the combined length of 3D. The coil 34 inserted from the upper end side of the tubular portion 33D is tightly fitted to the nominal shaft portion 33C of the tubular portion 33D and then firmly attached to the coil holding bobbin 33 by bonding.
Therefore, in the coil holding bobbin 33 that attaches and holds the coil 34, the upper end portion of the cylindrical portion 33D that is connected to the shaft portion 33C extends to the position of the opening portion of the coil 34.

By the way, since the heat transfer between the members having the same cross-sectional area is proportional to the heat transfer rate per unit time, as described above, the coil formed of aluminum nitride having a high heat transfer rate is used. The holding bobbin 33 allows the heat generated in the coil 34 attached to the coil holding bobbin 33 to be transferred more quickly than the conventional coil holding bobbin 3 made of Bakelite resin, in other words, the coil 34.
Has a greater heat dissipation effect.

A rotor member 35 is rotatably arranged on the outer peripheral portion of the coil holding bobbin 33 by a plurality of bearing members described later. The rotor member 35 is generally formed in a cup shape, and a magnet 36 is adhesively fixed to an inner peripheral portion of the coil 34 having a diameter slightly larger than the outer diameter of the coil 34. Of course, a slight air gap is held between the magnet 36 and the coil 34 so as not to hinder the rotation of the rotor member 35.

A bearing member for rotatably holding the rotor member 35 on the outer peripheral portion of the coil 34 attached to the coil holding bobbin 33 is a first bearing member arranged on the upper surface of the rotor member 35.
Bearing member 37, a second bearing member 38 disposed on the outer peripheral portion, and a third bearing member 39 disposed on the lower surface portion. Inside the first bearing member 37, the second bearing member 38, and the third bearing member 39, air holes (not shown) are provided, respectively. These air holes communicate with air leakage holes 43A opened on the surfaces of the bearing members 37, 38, 39 facing the rotor member 35. Therefore, the air supply unit 4 provided in the housing 32
The air supplied from No. 3 leaks through the air holes from the air leak outlets opened on the peripheral surfaces of the bearing members 37, 38, 39.

Due to the leakage of air from the air leakage port, an air layer is formed between the bearing members 37, 38, 39 and the outer peripheral surface of the rotor member 35, and the air layer floats as if the rotor member 35 were floating. A static pressure air bearing that rotatably holds is constructed. Thus, the rotor member 35
By being rotatably supported by the hydrostatic bearing, the can be precisely and silently rotated.

A rotor member 35 in which the polygon mirror device 20 is combined via a mounting shaft 22A or the like, or bearing members 37 for rotatably holding the rotor member 35,
The rotating portion constituted by 38 and 39 and the coil holding bobbin 33 in which the coil 34 is attached to the outer peripheral portion are integrally coupled by the attaching screw 41. That is, when the mounting screw 41 is screwed into the mounting hole provided in the flange portion 33A of the coil holding bobbin 33,
The coil holding bobbin 33 and the third bearing member 39 are joined together.

As described above, the coil holding bobbin 33
Since it is made of an aluminum nitride material, it has a sufficient strength as compared with the conventional coil holding bobbin 3 made of Bakelite resin, and the rotating portion including the rotor member 35 that rotates at an ultrahigh speed is directly attached. Is possible.

A shaft hole 35A is formed at the center of the ceiling of the rotor member 35. By fitting the mounting shaft 22A into the shaft hole 35A, the mirror mounting member 22 of the polygon mirror device 20 is rotated. It is combined with the member 35, and the mounting screw 22B is tightened to be integrated. A plurality of polygon mirrors 23 are attached to the outer peripheral portion of the mirror attaching member 22 by using attaching screws 22C.

The housing 21 constituting the outer peripheral portion of the polygon mirror device 20 is provided with a slit 21A corresponding to the polygon mirror 23. This slit 21A is provided.
The semiconductor laser enters the polygon mirror device 20 via the and is reflected by the polygon mirror 23.

The ultra-high-speed rotating coreless motor 30 constructed as described above, which is combined with the polygon mirror device 20 to form a high-speed horizontal polarization device as a whole, is controlled by the coil 34 attached to the outer peripheral portion of the coil holding bobbin 33. By supplying a current based on the signal, this coil 3
4 and the magnet 3 attached to the inner peripheral surface of the rotor member 35
For example, the rotor member 35 rotates at a super high speed of 80,000 revolutions per minute or more by using the magnetic force generated between the rotor member 35 and 6 as a drive source. By the rotation of the rotor member 35, the mirror mounting member 2
The polygon mirror 23 also rotates at a high speed via 2 and the semiconductor laser light incident from the slit 21A is scanned.

Since the rotor member 35 rotates at a high speed of 80,000 rpm or more, a large amount of heat is generated not only from the rotor bearing portion but also from the coil 34 in the ultra high speed coreless motor 30 of the embodiment. The heat generated from the coil 34 is quickly transmitted to the coil holding bobbin 33 formed of an aluminum nitride material having a high thermal conductivity characteristic, and is radiated through the heat radiating portion 33E or the housing 32. This heat radiating action can sufficiently cope with the amount of heat generated in the motor, and the heat is accumulated in the motor to cause the rotor member 35 or the bearing members 37, 38, 3
The thermal expansion of 9 and 9 does not cause an inconvenience that an appropriate air gap between these members cannot be maintained.

Further, when the rotor member 35 rotates at a high speed, not only the rotor member 35 but also the respective bearing members 37, 38, 39, the coil holding bobbin 33 and other constituent members vibrate. As described above, in the ultra-high speed coreless motor 30 of the embodiment, since the rotating portion including the rotor member 35 and the coil holding bobbin 33 are directly attached to each other, the assembling accuracy is improved.
The vibration of each component is small. Further, the coil holding bobbin 33 and the base member 31 are made of an elastic material, and
Since it is attached via the ring 40, the vibration of each component member is absorbed by the O-ring 40, and the quietness of the entire motor is further maintained.

Further, the coil holding bobbin 33 holding the coil 34 has the coil 3 formed by the shaft portion 33C and the cylindrical portion 33D.
By virtue of being configured to hold substantially the entire length of 4, the vibration of the coil 34 due to the high speed rotation of the rotor member 35 is prevented.

In the embodiment described above, the ultra-high-speed rotating coreless motor 30 for driving the polygon mirror, which is combined with the polygon mirror device 20 to form a high-speed horizontal polarization device as a whole, has been described. Of course, the coreless motor is also used for other purposes.

[0041]

As described above in detail, according to the ultra-high speed coreless motor according to the present invention, the coil holding bobbin having the coil mounted on the outer peripheral portion is formed of the ceramic having high thermal conductivity, so that the ultra high speed is achieved. The heat generated from the coil due to the rotation is efficiently transferred to the coil holding bobbin and radiated from the heat radiating portion of the coil holding bobbin or the housing. High speed rotation output can be obtained.

Further, according to the ultra-high speed coreless motor of the present invention, since the coil holding bobbin is made of high-strength ceramic, the rotor member can be directly and firmly attached to the bearing member or the like for rotatably supporting it. The assembly accuracy can be improved. Further, since the coil holding bobbin in which the rotating portion including the rotor member is directly assembled is attached to the base member via the elastic member, generation of vibration, noise and the like due to the ultra-high speed rotation is prevented. Furthermore, by forming the coil holding bobbin in the axial direction corresponding to the coil attached to the outer peripheral portion,
The coil is firmly held over almost the entire length, and vibration and the like are prevented from occurring.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of an ultrahigh speed coreless motor according to the present invention.

FIG. 2 is a vertical cross-sectional view of an assembly of a coil and a coil holding bobbin included in the same ultra-high speed coreless motor.

FIG. 3 is a vertical cross-sectional view of an assembly of a coil and a coil holding bobbin included in a conventional ultra high speed coreless motor.

FIG. 4 is a partially cutaway perspective view of the same ultra-high speed coreless motor.

FIG. 5 is a vertical cross-sectional view of the same ultra-high speed coreless motor.

[Explanation of symbols]

20 ... Polygon mirror device 23 ... Polygon mirror 30 ... (For driving polygon mirror) Ultra-high speed coreless motor 31 ... Base member 32 ... Housing 33 ... Coil holding bobbin 33A ... Flange Part 33B ··· Bobbin body part 33C · · Shaft part 33D · · Cylindrical part (extension shaft part) 33E · · Heat dissipation part 34 · · Coil 35 · · Rotor member 36 · · Magnet 37 · · First Bearing member 38 ... Second bearing member 39 ... Third bearing member 40 ... O-ring (elastic member) 41 ... Mounting screw 43 ... (For static pressure air bearing) Air supply unit

Claims (4)

[Claims] 1. A coil-holding bobbin fixed on a base member, wherein a coil is attached to an outer peripheral portion of the coil-holding bobbin and a magnet is attached to an inner peripheral surface of the coil-holding bobbin so that the magnet faces the coil. An ultra-high-speed rotating coreless motor characterized in that the coil holding bobbin is rotatably arranged on the outer periphery of the bobbin, and the coil holding bobbin is formed of a ceramic having high thermal conductivity. 2. The ultra-high speed coreless motor according to claim 1, wherein the ceramic forming the coil holding bobbin is aluminum nitride. 3. The ultra-high speed coreless motor according to claim 1, wherein the coil holding bobbin is fixed to the base member via an elastic member. 4. The ultra-high-speed rotating coreless motor according to claim 1, wherein the coil holding bobbin is formed so as to extend in the axial direction along the center hole of the coil attached to the outer peripheral portion.