JP3084600B2 - Dynamic pressure air bearing type optical deflector - Google Patents

Dynamic pressure air bearing type optical deflector

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Publication number
JP3084600B2
JP3084600B2 JP23913195A JP23913195A JP3084600B2 JP 3084600 B2 JP3084600 B2 JP 3084600B2 JP 23913195 A JP23913195 A JP 23913195A JP 23913195 A JP23913195 A JP 23913195A JP 3084600 B2 JP3084600 B2 JP 3084600B2
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Japan
Prior art keywords
dynamic pressure
air bearing
pressure air
thrust
type optical
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JP23913195A
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Japanese (ja)
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JPH0961742A (en
Inventor
伊佐雄 大川
明義 高橋
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日本電産コパル電子株式会社
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Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dynamic pressure air bearing type optical deflector used for information equipment, image equipment and measuring equipment.

[0002]

2. Description of the Related Art As conventional dynamic pressure air bearing type optical deflectors, there are ones using a mirror chamber inside at atmospheric pressure as shown in FIGS. 25 and 26, and those as shown in FIGS. 29 and 30. A radial dynamic pressure air bearing mechanism that evacuates the mirror chamber by a radial dynamic pressure air bearing mechanism (see Japanese Patent Application Laid-Open No. H05-027194) and a pressure herringbone groove as shown in FIGS. For evacuating the interior of the mirror chamber (Japanese Patent Laid-Open No. 5-134203)
Is known.

Hereinafter, these three types of conventional dynamic pressure air bearing type optical deflectors will be described in detail.

FIGS. 25 and 26 show an example of a conventional general dynamic pressure air bearing type optical deflector.
7, a motor rotating portion including a yoke 73, a permanent magnet 75, a sleeve 61, and the like, and a rotating polygon mirror 81 are provided on a radial dynamic pressure air bearing portion 6 around a fixed shaft 65a fixed to the base 63.
The motor rotating part and the rotating polygon mirror 81 are rotatably supported by the base 63 and the motor case 6.
9. It is housed inside the mirror chamber 85 sealed by the motor cover 71. Further, a thrust dynamic pressure air bearing portion 59 constituted by a thrust washer 51 fixed to the lower end surface of the sleeve 61 and the base 63 is supported in the thrust direction. In addition, there are known a type in which a radial bearing is supported by a rolling bearing such as a ball bearing, and a type in which a thrust direction is supported by a magnetic bearing or the like. The directions indicated by arrows in the figure are the thrust dynamic pressure air bearings 59, 59.
Shows the flow of air generated with the rotation of the motor. The spiral groove 53 (see FIGS. 27 and 28) formed in the thrust washer 51 causes the outer circumferential portion of the thrust washer 51 to move inside the mirror chamber 85. Air is inhaled,
The air is discharged from the upper end surface of the sleeve 61 to the mirror chamber 85 through the inside of the radial dynamic pressure air bearing portion 67a. Therefore, the air pressure inside the mirror chamber 85 is constant while keeping the air pressure hermetically closed, and is usually atmospheric pressure.

In the thus configured dynamic pressure air bearing type optical deflector, since the air pressure inside the mirror chamber 85 is almost atmospheric pressure, the sleeve 61 and the rotary polygon mirror 81 which rotate with the rotation of the motor are formed by The motor receives a resistance due to the air inside the mirror chamber 85, causing a loss in the motor. This loss increases as the rotating polygon mirror 81 is rotated at a higher speed. Further, when the rotating polygon mirror 81 rotates, a wind noise is generated by the air inside the mirror chamber 85, and this sound increases as the rotating polygon mirror 81 rotates at a high speed. Furthermore, the rotating polygon mirror 81
Generates frictional heat due to the air inside the mirror chamber 85, and this heat is transmitted to the entire motor. Here, FIG. 35 shows an example of a motor loss caused by the resistance of the rotating polygon mirror 81 to the air inside the mirror chamber 85. The allowable loss of the motor is determined by the input voltage, the motor coil resistance, the torque constant, and the heat radiation capability.
In the case of [W], the rotating polygon mirror 81 which generates the loss shown in FIG. 35 can increase the rotation speed only to 20,000 [rpm]. In order to further increase the number of rotations and rotate the motor, it is conceivable to increase the input voltage by increasing the number of coil turns. However, it is not possible to reduce the wind noise caused by the rotating polygon mirror 81 and to reduce the heat generation of the motor. Can not. In addition, there has been a problem that the cost of the drive circuit is increased by increasing the input voltage. It is conceivable that the interior of the mirror chamber 85 is evacuated in advance during assembly. However, in this case, the assembly process is complicated and the cost increases, and the interior of the mirror chamber 85 is evacuated by an external vacuum device or the like during operation. However, in this case, there is a practical problem such as the necessity of other equipment.

Next, FIGS. 29 and 30 are made to solve these disadvantages.
No. 94 is disclosed. The dynamic pressure air bearing type optical deflector is fixed to the base 63, and has an atmosphere communication portion communicating with the atmosphere in the longitudinal direction of the center of the fixed shaft 65b having herringbone grooves 87 and 89 formed on the outer periphery. 5
7a, and at the center of the pair of herringbone grooves 89, 87, the air communication portion 5 communicating with the air communication portion 57a.
5a and 55b are provided, and the air in the mirror chamber 85 is sucked from both end surfaces of the sleeve 61 by the action of the radial dynamic pressure air bearing portion 67b generated with the rotation of the motor, and the air communication portions 55a and 55b are provided. The inside of the mirror chamber 85 is evacuated by discharging the air to the outside of the mirror chamber 85 through the filter 55 and the atmosphere communication part 57a and the filter 79. In the dynamic pressure air type optical deflector configured as described above, as can be seen from the pressure distribution during stable operation of the radial dynamic pressure air bearing shown in FIG. However, there is a problem that although the pressure becomes higher than the other parts, the pressure becomes higher than other parts, but it is insufficient to obtain a desired bearing rigidity.

FIGS. 31 and 32 are provided to further solve these disadvantages.
No. 203 is disclosed. This dynamic pressure air bearing type optical deflector is fixed to a base 63 and has a herringbone groove 87 on its outer periphery in order to increase the radial bearing rigidity of the dynamic pressure air bearing type optical deflector shown in FIGS. , 89 and the radial dynamic pressure air bearing 67
c at each end of herringbone groove 91 for pressurizing,
An air communication portion 57b communicating with the atmosphere is provided in the longitudinal direction of the center of the fixed shaft 65c where the 93 is engraved, and the air communication portion 57b communicates with the pressurized herringbone grooves 93 and 91 and the herringbone grooves 89 and 87 adjacent thereto. At the center position, this air communication part 5
The air communication portions 55d and 55c communicating with the sleeve 7b are provided, and the air in the mirror chamber 85 is sucked from both end surfaces of the sleeve 61 by the action of the radial dynamic pressure air bearing portion 67b generated by the rotation of the motor. And the air communication unit 55
The inside of the mirror chamber 85 is evacuated by discharging to the outside of the mirror chamber 85 via the filter 79 and the air communication portion 57b and the filter 79. In the dynamic pressure air type optical deflector configured as described above, as can be seen from the pressure distribution during stable operation of the radial dynamic pressure air bearing shown in FIG. Since the air communication portions 55d and 55c are not formed in, a value higher than the atmospheric pressure can be obtained, and a desired bearing rigidity can be obtained. However, since a pressing herringbone groove is required in addition to a normal herringbone groove, the axial length is reduced.
Therefore, there is a problem that it is difficult to reduce the size in the axial direction, and that the herringbone groove needs to be processed extra, thus complicating the manufacturing process and increasing the cost.

[0008]

SUMMARY OF THE INVENTION In view of the above-mentioned drawbacks of the prior art, the present invention evacuates the interior of the mirror chamber without the need for other external devices, and generates motor loss and wind noise due to air resistance. It is another object of the present invention to provide a pneumatic optical deflector capable of reducing the amount of heat generated by a motor.
Also, a desired radial bearing rigidity is obtained, and
It is an object of the present invention to provide a dynamic pressure air bearing type optical deflector whose axial dimension is the same as that of the conventional type, and can use the parts of the conventional dynamic pressure air bearing type optical deflector almost as it is.

[0009]

In order to achieve the above-mentioned object, the present invention provides a rotary polygon mirror or a motor rotary unit rotatable together with a rotary polygon mirror inside a case and a cover member. In the dynamic pressure air bearing type optical deflector housed in the motor, a thrust dynamic pressure air bearing portion generated along with the rotation of the motor rotating portion is provided vertically so as to sandwich the motor rotating portion. And the air suction is performed from the outer peripheral portion of the spiral groove of the thrust dynamic pressure air bearing portion located inside the mirror chamber, and the air is discharged from the inner peripheral portion of the spiral groove of the thrust dynamic pressure air bearing portion to the atmosphere. By performing the operation outside the case through the communication part, the air pressure in the mirror chamber is reduced, and the opening end of the mirror chamber of the air communication part is set to the bearing end of the radial dynamic pressure air bearing part. By maintaining the pressure at the bearing end of the radial dynamic pressure air bearing portion at atmospheric pressure, and by increasing the bearing rigidity of the radial dynamic pressure air bearing portion, a dynamic pressure air bearing type optical deflector is configured. I have. In addition, the spiral groove forming the thrust dynamic pressure air bearing portion has a different engraving direction between the outer peripheral side and the inner peripheral side, and the outer peripheral side groove for sucking air inside the mirror chamber has a shorter length. By making the length longer than the length of the groove on the inner peripheral side, a dynamic pressure air bearing type optical deflector is formed.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to embodiments of the invention shown in the drawings.

FIG. 1 to FIG. 6 are views showing a first embodiment of the present invention. Reference numeral 13a in FIGS. 1 and 2 denotes a base on which a fixed shaft 65a having a herringbone groove (not shown) engraved on its outer periphery is fixed. A sleeve 61 on which a rotating polygon mirror 81 is mounted is rotatably supported by a radial air bearing 67a on the outer periphery of the fixed shaft 65a. A magnet 75 is fixed to the lower outer periphery of the sleeve 61, a yoke 73 around which a coil 77 is wound is fixed to the motor case 69 so as to face the magnet 75, and a substrate on which a Hall element and the like are mounted. 83 is the base 13a
It is stuck to. A motor is configured by a motor rotating unit including the sleeve 61, the magnet 75, and the rotary polygon mirror 81, and a motor driving unit including the yoke 73, the coil 77, and the substrate 83. This motor is accommodated in the base 13a, the motor case 69, and the motor cover 15a, and this space is referred to as a mirror chamber 85. In a conventional dynamic pressure air bearing type optical deflector, the mirror chamber 85 is generally in a sealed state and is isolated from the outside. Reference numeral 1a denotes a lower thrust washer in which a spiral groove 53 is engraved. As shown in FIGS. 5 and 6, an inner peripheral portion is provided with an atmosphere communication portion 5a for communicating with the atmosphere. However, in this embodiment, since the lower thrust washer 1a is fixed to the base 13a, it is impossible to communicate with the atmosphere only by the air communication portion 5a provided in the lower thrust washer 1a. 13a is provided with an atmosphere communication portion 7a which communicates with the atmosphere communication portion 5a. Reference numeral 2a denotes an upper thrust washer in which a spiral groove (not shown) opposite to the lower thrust washer 1a is engraved. Like the lower thrust washer 1a, an air communication portion 5b communicating with the atmosphere is provided on the inner peripheral portion. I have. The upper thrust washer 2a is connected to the motor cover 15a and the fixed shaft 6
Unlike the lower thrust washer 1a, the motor cover 15a does not need to be provided with an air communication part because it is interposed between the lower cover 5a and the lower thrust washer 1a. Also, the lower thrust washer 1a
If provided in the same manner as the upper thrust washer 2a, the base 13
The air communication part 7a of a may be unnecessary.

In the dynamic pressure air bearing type optical deflector configured as described above, the coil 77 is energized to rotate the motor rotating portion, so that the radial dynamic pressure air bearing portion 67a and the thrust dynamic pressure air bearing portion 9a are provided. Generates dynamic pressure, and the fixed shaft 6
A motor rotating portion is supported so as to be rotatable around the outer periphery of 5a. When the flow of air by the thrust dynamic pressure air bearing portion 9a at this time is compared with the thrust dynamic pressure air bearing portion 59 (see FIGS. 25 and 26) of the conventional dynamic pressure air bearing type optical deflector,
As shown by an arrow in the drawing, the air flow from the conventional thrust dynamic pressure air bearing portion 59 sucks air in the mirror chamber 85 from the outer peripheral portion of the thrust washer 51, and the air flows into the radial dynamic pressure air bearing portion. After passing through the inside of 67 a, it is returned from the upper end surface of the sleeve 61 into the mirror chamber 85 again. Therefore, the air pressure in the mirror chamber 85 becomes constant. On the other hand, the flow of air by the thrust dynamic pressure air bearing portion 9a of the dynamic pressure air bearing type optical deflector shown in FIGS. 1, 3 and 4 according to the first embodiment of the present invention is shown in FIG. As shown by arrows, the air in the mirror chamber 85 is sucked from the outer periphery of each of the lower thrust washer 1a and the upper thrust washer 2a.
The air is discharged from the atmosphere communication portions 5a, 7a and 5b to the outside of the mirror chamber 85 without passing through the inside of the radial dynamic pressure air bearing portion 67a. As a result, the atmospheric pressure inside the mirror chamber 85 gradually decreases, and reaches 0.4 [atm] or less as an example, as shown in FIG. At this time, the pressure distribution of the thrust dynamic pressure air bearing 9a is, as shown in FIG. 17, the inner peripheral portion (the side where the atmosphere communication portion 5a is provided).
Is the atmospheric pressure, and the pressure at the outer peripheral portion is the same as the pressure inside the mirror chamber 85. It has been confirmed by experiments that the thrust dynamic pressure air bearing portion sufficiently exhibits its function even in such a pressure distribution. When the pressure distribution of the radial dynamic pressure air bearing 67a at this time was confirmed, both end surfaces of the sleeve 61, which is the air suction portion of the radial dynamic pressure air bearing 67a, were connected to the atmosphere communication portions 5a and 7a.
And 5b, the pressure distribution is the same as that of the conventional radial dynamic pressure air bearing. For this reason, the main components of the conventional dynamic pressure air bearing type optical deflector can be diverted as they are without deteriorating the bearing rigidity in the radial direction, and the inside of the mirror chamber 85 can be easily evacuated, and the air It is possible to reduce the loss of the motor due to the resistance, reduce the wind noise caused by the rotating polygon mirror 81 and the like, and reduce the heat generation of the motor. Further, since the size of the motor can be reduced as compared with the related art, it is possible to provide a dynamic pressure air bearing type optical deflector that is smaller and capable of rotating at high speed.
FIG. 2 is a view showing a state in which the dynamic pressure air bearing type optical deflector according to the first embodiment of the present invention is stopped, and the lower thrust washer 1a and the lower end surface of the sleeve 61 are in contact with each other in this state. However, with the rotation of the motor rotating part, a dynamic pressure is generated in the thrust dynamic pressure air bearing 9a, and the motor rotating part floats. After that, the motor rotating part floats further,
When the distance between the upper thrust washer 2a and the upper end surface of the sleeve 61 is reduced, and dynamic pressure is generated also in the thrust dynamic pressure air bearing 9b, and both forces are balanced, stable rotation as shown in FIG. I will be.

FIGS. 7 and 8 are views showing a lower thrust washer 1b according to a second embodiment of the present invention, in which an air communication portion 5c is provided in addition to the air communication portion 5a described above. is there. As described above, the same effect can be obtained even if the spiral groove 53 is cut off in the middle.

FIGS. 9 and 10 show a lower thrust washer 1f according to a third embodiment of the present invention.
A conventional thrust washer 51 shown in FIGS.
Is provided with an atmosphere communication portion 5a. Even with such a configuration, the same effect as in the first embodiment of the present invention can be obtained. Although not shown, an air communication portion 5c may be provided as in the second embodiment of the present invention.

FIGS. 11 to 14 are views showing a lower thrust washer 1c and an upper thrust washer 2c according to a fourth embodiment of the present invention. The spiral groove engraved on the washer has a different engraving direction between the outer peripheral part and the inner peripheral part of the thrust washer, and the length of the groove engraved on the outer peripheral part is engraved on the inner peripheral part. It is longer than the length of the groove. In the thus configured dynamic pressure air bearing type optical deflector, as shown in FIGS. 19 and 20, the pressure distribution of the thrust dynamic pressure air bearing portion (see 9a in FIG. 1) is the first pressure distribution shown in FIG. Is different from the embodiment of FIG.
, The bearing rigidity in the thrust direction can be further increased. FIG. 19 shows a pressure distribution immediately after the start of the motor rotating unit. In this state, the pressure at the outer peripheral portions (Ro) of the thrust washers 1c and 2c is substantially 1 [atm]. Thereafter, the air pressure inside the mirror chamber 85 decreases due to the pumping action of the thrust dynamic pressure air bearing portion, so that the pressure at the outer peripheral portion (Ro) is reduced as shown in FIG.
As shown by 0, the pressure becomes the same as the atmospheric pressure inside the mirror chamber 85, and accordingly, the pressure of Rm also slightly decreases. However, even in that state, the value equal to or higher than the atmospheric pressure is maintained, and it can be seen that the bearing rigidity in the thrust direction is maintained even in the stable rotation state.

FIGS. 15 and 16 show a lower thrust washer 1d according to a fifth embodiment of the present invention.
Lower thrust washer 1b according to the second embodiment of the present invention
Even if the spiral groove 3a is cut off in the same way as
The same effects as in the fourth embodiment of the present invention can be obtained.

FIGS. 21 to 24 show another embodiment of the present invention. In FIG. 21, a sleeve 11a is shown.
Spiral grooves are engraved at both ends of the sleeve 11a.
The thrust washer 1 is attached to a portion of each of the motor cover 15d and the base 13b which faces the end portion of the motor cover 15d and the fixed shaft 65a.
Since the air communication portions 7c and 7b are provided in the same manner as in a and 2a, the same effects as described above can be obtained.

In FIG. 22, as a thrust washer, a lower thrust washer 1e (see FIGS. 7 and 8) having no atmosphere communication portion 5c but having only an atmosphere communication portion 5c and an upper thrust washer 2e having the same structure are provided. The air inside the mirror chamber 85 by the thrust dynamic pressure air bearings 9e, 9f is provided from the respective air communication portions 5c, 5d of the thrust washers 1e, 2e in the axial center direction of the fixed shaft 17. The air is discharged from the filter 79 to the outside of the mirror chamber 85 through the air communication sections 5g and 5h and the air communication section 7d provided in the center longitudinal direction of the fixed shaft 17 communicating with the air communication sections 5g and 5h. The same effect as described above can be obtained, and the function of the filter 79 can prevent entry of external dust and the like. It is possible to maintain the chamber 85 inside the always clean.

In FIG. 23, even when the spiral groove and the air communication portion 5f are provided on the end surface (the upper end surface in the figure) of the sleeve 11b, the spiral groove and the air communication portion 5e are provided on the base 13c facing the lower end surface of the sleeve 11b. This shows that the same effect can be obtained by providing the fixed shaft 17 with the air communication portions 7d, 5g, and 5h as in FIG.

Originally, it is desirable to provide an air communication portion (5a, 5c, etc.) on a thrust washer or a base corresponding thereto, but conventional thrust washers 51, 5 are provided.
This shows that even if 1 ′ is adopted, the inside of the mirror chamber 85 can be evacuated by the configuration as shown in FIG.

[0021]

As is clear from the above description, the following effects can be obtained in the present invention.

(1) In a dynamic pressure air bearing type optical deflector in which the outer periphery of a fixed shaft erected on a case is housed in a case and a cover member and a rotating polygonal mirror or a motor rotating unit rotatable together with the rotating polygonal mirror is provided in the case. A thrust dynamic pressure air bearing portion generated along with the rotation of the rotating portion is provided in a vertical direction so as to sandwich the motor rotating portion, and the motor rotating portion is supported in the thrust direction, and the air suction is performed inside the mirror chamber. The outer periphery of the spiral groove of the thrust dynamic pressure air bearing located at By lowering the internal air pressure and arranging the opening end of the mirror chamber of the atmospheric communication section at the bearing end of the radial dynamic pressure air bearing section, the radial dynamic pressure air bearing section The dynamic pressure air bearing type optical deflector is constructed by maintaining the pressure of the bearing end at atmospheric pressure and increasing the bearing rigidity of the radial dynamic pressure air bearing unit. The pressure inside the mirror chamber can be made lower than the atmospheric pressure while most of the components are diverted. Therefore, due to the air resistance of the rotating portion of the motor, no loss is generated in the motor, the noise due to the wind noise of the rotating polygonal mirror can be reduced, and the heating of the rotating polygonal mirror does not occur. Can be suppressed. In addition, it is possible to reduce the size of the motor in the axial direction while maintaining the desired rigidity of the bearing in the radial direction, and the loss of the motor is small. A compressed air bearing type optical deflector can be obtained.

(2) Since a dynamic pressure air bearing type optical deflector is formed by providing an atmosphere communication portion communicating with the atmosphere inside the fixed shaft, even if a conventional thrust washer is employed, the interior of the mirror chamber is not affected. Can be made lower than the atmospheric pressure, and the same effect as (1) can be obtained.

(3) A dynamic pressure air bearing type optical deflector is provided by providing an atmosphere communication portion communicating with the atmosphere on a base or a motor case which constitutes a thrust dynamic pressure air bearing portion. Alternatively, the same effect as (1) can be obtained by forming spiral grooves on both end surfaces of the sleeve.

(4) The spiral groove forming the thrust dynamic pressure air bearing portion has a different engraving direction between the outer peripheral side and the inner peripheral side, and the outer peripheral side groove for sucking air inside the mirror chamber. By making the length longer than the length of the groove on the inner peripheral side, a dynamic pressure air bearing type optical deflector is constructed, and the pumping action of the thrust dynamic pressure air bearing reduces the air pressure inside the mirror chamber. However, the pressure distribution in the thrust dynamic pressure air bearing can be improved, and the bearing rigidity in the thrust direction can be increased. Therefore, it is possible to obtain a dynamic pressure air bearing type optical deflector suitable for higher speed rotation. Further, when it is necessary to enlarge the optical scanning surface, it is possible to obtain a dynamic pressure air bearing type optical deflector which can be sufficiently supported even if the weight of the rotary polygon mirror increases.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an operation state of a dynamic pressure air bearing type optical deflector according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing the stopped state of the dynamic pressure air bearing type optical deflector according to the first embodiment of the present invention.

FIG. 3 is a sectional view of a main part around an upper thrust dynamic pressure air bearing unit according to the first embodiment of the present invention.

FIG. 4 is a sectional view of a main part around a lower thrust dynamic pressure air bearing unit according to the first embodiment of the present invention.

FIG. 5 is a plan view of a lower ring washer according to the first embodiment of the present invention.

FIG. 6 is a cross-sectional view of the lower ring washer according to the first embodiment of the present invention.

FIG. 7 is a plan view of a lower ring washer according to a second embodiment of the present invention.

FIG. 8 is a cross-sectional view of a lower ring washer according to a second embodiment of the present invention.

FIG. 9 is a plan view of a lower ring washer according to a third embodiment of the present invention.

FIG. 10 is a cross-sectional view of a lower ring washer according to a third embodiment of the present invention.

FIG. 11 is a plan view of a lower ring washer according to a fourth embodiment of the present invention.

FIG. 12 is a cross-sectional view of a lower ring washer according to a fourth embodiment of the present invention.

FIG. 13 is a cross-sectional view of an upper ring washer according to a fourth embodiment of the present invention.

FIG. 14 is a bottom view of the upper ring washer according to the fourth embodiment of the present invention.

FIG. 15 is a plan view of a lower ring washer according to a fifth embodiment of the present invention.

FIG. 16 is a cross-sectional view of a lower ring washer according to a fifth embodiment of the present invention.

FIG. 17 is a diagram showing a pressure distribution during a stable operation of the thrust dynamic pressure air bearing unit according to the first embodiment of the present invention.

FIG. 18 is a diagram showing a temporal change in pressure inside a mirror chamber of the dynamic pressure air bearing type optical deflector of the present invention.

FIG. 19 is a diagram showing a pressure distribution immediately after starting of a thrust dynamic pressure air bearing unit according to a fourth embodiment of the present invention.

FIG. 20 is a diagram showing a pressure distribution during a stable operation of a thrust dynamic pressure air bearing unit according to a fourth embodiment of the present invention.

FIG. 21 is a cross-sectional view showing an operation state of a dynamic pressure air bearing type optical deflector according to a sixth embodiment of the present invention.

FIG. 22 is a cross-sectional view showing an operating state of a dynamic pressure air bearing type optical deflector according to a seventh embodiment of the present invention.

FIG. 23 is a cross-sectional view showing an operation state of a dynamic pressure air bearing type optical deflector according to an eighth embodiment of the present invention.

FIG. 24 is a cross-sectional view showing an operating state of a dynamic pressure air bearing type optical deflector according to a ninth embodiment of the present invention.

FIG. 25 is a cross-sectional view showing an operation state of a conventional dynamic pressure air bearing type optical deflector.

FIG. 26 is a sectional view of a main part around a thrust dynamic pressure air bearing portion of a conventional dynamic pressure air bearing type optical deflector.

FIG. 27 is a plan view of a thrust washer of a conventional dynamic pressure air bearing type optical deflector.

FIG. 28 is a cross-sectional view of a thrust washer of a conventional dynamic pressure air bearing type optical deflector.

FIG. 29 is a cross-sectional view showing a stopped state of the second conventional dynamic pressure air bearing type optical deflector.

FIG. 30 is a half sectional view showing an operation state of a radial dynamic pressure air bearing portion of a second conventional dynamic pressure air bearing type optical deflector.

FIG. 31 is a cross-sectional view showing a stopped state of a third conventional dynamic pressure air bearing type optical deflector.

FIG. 32 is a half sectional view showing an operation state of a radial dynamic pressure air bearing portion of a third conventional dynamic pressure air bearing type optical deflector.

FIG. 33 is a view showing a pressure distribution during stable operation of a radial dynamic pressure air bearing portion of a second conventional dynamic pressure air bearing type optical deflector.

FIG. 34 is a view showing a pressure distribution during stable operation of a radial dynamic pressure air bearing portion of a third conventional dynamic pressure air bearing type optical deflector.

FIG. 35 is a diagram showing motor loss due to air resistance.

[Explanation of symbols]

1a, 1b, 1c, 1d, 1e, 1f: lower thrust washer, 2a, 2c, 2e: upper thrust washer, 3a, 3b: spiral groove, 5a, 5b, 5c, 5d, 5e, 5f, 5g, 5h: open air Communication part, 7a, 7b, 7c, 7d: outside air communication part, 9a, 9b, 9c, 9d, 9e, 9f, 9g, 9h: thrust dynamic pressure air bearing part, 11a, 11b: sleeve, 13a, 13b, 13c: Base, 15a, 15b, 15c: motor cover, 17: fixed shaft, 51, 5
1 ': thrust washer, 53: spiral groove, 55a, 55b, 55c, 55d: outside air communication section, 57a, 57b: outside air communication section, 59a, 59b: thrust dynamic pressure air bearing section, 61: sleeve, 63: base 65a, 65b, 65c: fixed shaft, 67a, 67b, 67c: radial dynamic pressure air bearing, 69: motor case, 71: motor cover, 73: yoke, 75: magnet, 77: coil, 79: filter, 81: Rotating polygon mirror, 83: substrate, 85: mirror chamber, 87, 89: herringbone groove, 91, 93:
Herringbone groove for pressurization.

Claims (2)

(57) [Claims]
1. A dynamic pressure air bearing type optical deflector in which an outer periphery of a fixed shaft erected on a case is rotatable together with a rotary polygon mirror or a rotary polygon mirror is housed in a case and a cover member. The thrust dynamic pressure air bearing part generated with the rotation of the part is moved up and down so as to
Direction, and support this motor rotating part in the thrust direction.
Rutotomoni, to position each inner mirror chamber air inhalation of its
The air is discharged from the outer periphery of the spiral groove of the thrust dynamic pressure air bearing , and air is discharged from the spiral of the thrust dynamic pressure air bearing.
By performing the casing outside via the atmosphere communication portion from the inner periphery of the groove, it allowed lowering the pressure in the mirror chamber section, and, before
By arranging the opening end in the mirror chamber of the atmospheric communication portion at the bearing end of the radial dynamic pressure air bearing portion, the pressure of the bearing end portion of the radial dynamic pressure air bearing portion is maintained at the atmospheric pressure.
A dynamic air bearing type optical deflector characterized by increasing the bearing rigidity of the air dynamic pressure air bearing portion .
2. The spiral groove forming the thrust dynamic pressure air bearing portion has a different engraving direction between the outer peripheral side and the inner peripheral side, and the outer peripheral side groove for sucking air inside the mirror chamber is formed. The dynamic pressure air bearing type optical deflector according to claim 1, wherein the length is longer than the length of the groove on the inner peripheral side.
JP23913195A 1995-08-24 1995-08-24 Dynamic pressure air bearing type optical deflector Expired - Lifetime JP3084600B2 (en)

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Application Number Priority Date Filing Date Title
JP23913195A JP3084600B2 (en) 1995-08-24 1995-08-24 Dynamic pressure air bearing type optical deflector

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JPH0961742A JPH0961742A (en) 1997-03-07
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JP4519301B2 (en) * 2000-10-02 2010-08-04 日本電産コパル電子株式会社 Optical deflector
JP6769177B2 (en) 2016-08-30 2020-10-14 コニカミノルタ株式会社 Image forming device, control method, and control program
CN108869532A (en) * 2018-09-12 2018-11-23 大连海事大学 Novel kinetic pressure gas thrust bearing based on centripetal pressurization principle

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9709092B2 (en) 2014-05-12 2017-07-18 Nidec Copal Electronics Corporation Fluid dynamic bearing, motor, and optical deflector

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