JPH0145306B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a motor, and particularly to a motor that can provide highly accurate and stable rotation suitable for a rotating mirror light deflection device.

Various functions are generally required of a motor, and in particular, a motor applied to a rotating mirror light deflecting device is required to operate stably with high precision at least in a steady rotating operation state. This is because, as is well known in the art of rotating mirror light deflection devices, when performing operations such as reading or writing information, the rotating mirror is rotated to continuously change the angle of incidence of the incident light, and the reflected light is used to perform linear scanning. It has gained. Therefore, if the rotation of the rotating mirror is eccentric or uneven, proper linear scanning cannot be obtained. In order to improve rotational accuracy in this respect, in addition to rotating the motor rotation shaft with high precision, it is necessary to precisely rotate the motor rotation shaft with a rotating mirror that is a rotationally driven object, or a rotation transmission means that applies rotational driving force to the rotating mirror. For this type of motor, it is not enough to simply construct the motor with high precision; it is desirable to assemble the motor with consideration to the mounting of the rotating driven body. .

In consideration of such circumstances, a so-called outer rotor type motor has been proposed. When using an outer rotor type motor in a rotating mirror light deflection device, the shaft on which the motor stator etc. is attached (which becomes the rotation center axis of the rotor) is fixed to a machine base, etc., and the rotating mirror is connected to the outer rotor. Install and use. Therefore, compared to the case of using an inner rotor type motor, this has the advantage that the accuracy of the motor rotation axis can be easily achieved because the rotation center axis itself is fixed.

However, a drawback of using the above-mentioned outer rotor type motor in a rotating mirror light deflection device is that the rotating mirror is attached to the outer rotor, so its outer diameter cannot be made very small (normally, the diameter is approximately
Difficult to use for rotating mirrors smaller than 80mm. ), it is difficult to install the rotating mirror only after the outer rotor has been assembled, and the accuracy of the rotating mirror must be achieved after the outer rotor is attached to the fixed rotation center shaft via a bearing, that is, after the motor In some cases, there is no point in doing this unless it is almost completely assembled. Also, because of the outer rotor structure, there were also difficulties in the heat dissipation of the motor.

In view of the above-mentioned circumstances, the present invention provides a motor having a structure that allows highly accurate and stable rotational operation and does not make the assembly and manufacturing process complicated or difficult. The basic structure of the motor of the present invention having such characteristics is that at least both ends of the motor shaft to which the rotary drive rotor and the rotary driven body are fixed are hollow, and the fixed support shaft is inserted into the hollow part. The rotary shaft of the motor is rotatably supported via a bearing. Furthermore, based on the above basic configuration, it is also possible to add an additional configuration to eliminate the adverse effects caused by oil mist generated from the motor bearing.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is an external perspective view showing an embodiment of the motor of the present invention. In FIG. 1, reference numeral 1 indicates a rotation drive unit, 2 a rotating mirror, 3 a rotation detection unit, 5 a fixed support shaft, and 6 a fixed part such as a frame.

As will be described later, a stator or a motor rotor for rotationally driving a motor is provided in the rotation drive section 1 as a known means per se. The rotating mirror 2 is attached to a motor rotation shaft different from the fixed support shaft 5 so as to be rotatable by the rotation of the motor, and rotates around a rotation center determined by the fixed support shaft 5. If the rotating mirror 2 rotates, for example, clockwise in the figure, the reflected light of the incident light P is scanned in the direction of the arrow A in the figure, and the number of scans in one rotation of the rotating mirror 2 is the number of reflection surfaces of the rotating mirror 2. determined by. The important thing here is that the rotating mirror 2
It must be strictly set so that each scan associated with the rotational movement of the scanner is performed at the same position, that is, on the same scanning line. From this point, rotating mirror 2
It is required that the rotating shaft of the motor that directly rotates the motor has no wobbling, and that the rotating mirror is properly attached and fixed to the rotating shaft. The internal structure of the motor of the present invention, which easily satisfies such requirements, is as shown in the cross-sectional view of the main part shown in FIG. 2, for example.

FIG. 2 shows a cross section of the main parts of the motor shown in FIG. 1, and the same parts as in FIG. 1 are given the same reference numerals. In FIG. 2, 7 is a motor rotation shaft, 11 is a support case, 12 is a motor rotor, 1
4 is a motor stator, 16 is a Hall sensor, 31
32 is an encoder, 32 is an information reading sensor, 33 is a fixed frame, 51 is a bearing, 55 is a gas flow path, 55a, 5
Reference numeral 5b indicates the opening of the gas flow path, 72 indicates the opening of the support case, 80 indicates the opening of the rotating driven body, 84 indicates the opening of the fixed frame, 90 indicates the collar, and 92 and 94 indicate the openings of the motor rotating shaft.

The support case 11 has a U-shaped cross section and is completely open at one end. On the other hand, an opening 72 is formed in the center of the side surface 70 on the opposite side, through which the fixed support shaft 5 is inserted and attached. A motor stator 14 and a Hall sensor 16 for rotationally driving the motor are attached to the support case 11. This hall sensor 1
6 performs the action of a brush in a normal brush motor, and can control rotation without contact. Support case 11 is disposed at one end of the motor.

The rotating mirror 2 as a rotating driven body has a fixed support shaft 5.
The outer peripheral surface parallel to is formed of a polygonal mirror surface. At the center in the radial direction is a motor rotation shaft 7.
An opening 80 is formed for inserting and attaching. The rotating mirror 2 is disposed approximately in the middle of the motor.

The fixed frame 33 has a U-shaped cross section and is completely open at one end. On the other hand, an opening 84 is formed in the center of the side surface 82 on the opposite side, through which the fixed support shaft 5 is inserted and attached. An information reading sensor 32 of the encoder 31 is attached to the fixed frame 33 . Fixed frame 3
3 is disposed at the end of the motor opposite to the support case 11.

The motor rotating shaft 7 is hollow and has openings 92 and 94 formed at both ends of the shaft. A collar 90 is provided on the outer periphery of the motor rotating shaft 7 at approximately the center in the axial direction.
is provided. The rotating mirror 2 is pressed and fixed against this collar 90. Motor rotation shaft 7
A motor rotor 12 is attached to one end of the
An encoder 31 is attached to the other end.

A gas flow path 55 extending in the axial direction is formed in the fixed support shaft 5 . Gas flow path 55
are openings 55a and 55b that extend outside the fixed support shaft.
It is equipped with The fixed support shaft 5 supports the motor rotating shaft 7 via a bearing 51 such as a bearing. The motor rotation shaft 7 rotates about the axial center of the fixed support shaft 5. The fixed support shaft 5 is inserted through the opening 72 of the support case and the opening 84 of the fixed frame, and both ends thereof are fixed to the pedestal 6.

In the motor with the above configuration, power is supplied to the motor stator 14, and the Hall sensor 16
The motor rotor 12 is electromagnetically driven and rotated about the fixed support shaft 5 by the drive control signal. At the same time, the encoder 31 and the rotating mirror 2 rotate integrally, and the rotating mirror 2 is subjected to optical scanning as described above, while the encoder 31, together with the sensor 32, detects a rotation signal to control the rotation of the motor. is fed back to the Hall sensor 16, and the requested
It is used for PLL control (phase lock loop control) to stabilize motor rotation.

It is convenient to assemble a motor having the above structure and operation as follows. That is, first, the fixed support shaft 5 is prepared, and the motor rotating shaft 7 is attached to it via the bearing 51. After confirming that the rotary shaft 7 is properly attached to the fixed support shaft 5, the rotor 12, rotary mirror 2, and encoder 31 are sequentially attached. After that, the support case 11 to which the stator 14 is already attached and the fixed frame 33 to which the photo sensor 32 is attached are fixed to the fixed support shaft 5 by an appropriate method. Since it is possible to assemble it in this way, the motor rotation shaft 7
With the rotating mirror 2 attached to the rotary mirror 2, it is possible to achieve mounting accuracy of the rotating mirror, and it is also possible to achieve rotational accuracy around the fixed support shaft 5. In some cases, in order to obtain strict accuracy taking these into account, after assembling the fixed support shaft, motor rotating shaft, and rotating mirror, each reflective surface of the rotating mirror may be corrected by cutting and polishing to obtain high precision. Can be done. After obtaining the accuracy of the rotating mirror in this manner, all remaining parts are attached, so that assembly is easy and at the same time accuracy can be maintained reliably during assembly. Furthermore, since the motor rotor and stator can be brought into contact with the outside air, heat dissipation is also good.

The gas flow path 55 contributes to preventing the oil mist generated in the bearing 51 from spreading. For this purpose, the gas flow path 5
5 has two openings 55 extending outside the fixed support shaft.
a and 55b are formed on both sides of the bearing 51. Then, as shown in Fig. 3, the motor rotation shaft 7
A suction pipe 8 is connected to the opening 55b on the outside, and suction is thereby performed. Note that the symbols used in FIG. 3 are the same as those used in FIG. 2 for the same members. According to the suction of the suction pipe 8, an air flow shown by the arrow in FIG. 3 is generated. In other words, the motor rotation shaft 7 is
Air flows into the opening 5 of the fixed support shaft 5.
5a, and then exits to the opening 55b. Therefore, even if the motor rotates at high speed and oil mist is generated from the bearing, it will not be spread around. The influence of this oil mist cannot be ignored, especially in a rotating mirror light deflection device, and is a problem that must be solved in this type of device, as detailed in, for example, Japanese Patent Laid-Open No. 142166/1983.

As described above, in the motor of the present invention, the motor rotation shaft to which a rotary driven object such as a rotating mirror is fixed is supported by a fixed support shaft, and this fixed support shaft is connected to the rotation center axis of the motor rotation shaft. Therefore, if the motor is fixed to the applicable equipment or mount via this fixed support shaft, the rotation center axis of the motor rotation shaft itself will be used as the mounting reference part, so the rotation of the rotating driven object will be Rotation accuracy can be easily increased. Moreover, when assembling the motor, it is possible to first fix the required parts to the motor rotation shaft and then sequentially incorporate other parts, so it is possible to achieve precision when attaching the rotating driven body to the motor rotation shaft. without waiting for the completion of the motor assembly process.
This is the one that can perform the accuracy check that has the greatest impact.

Further, in the motor of the present invention, a fixed support shaft can be used for removing oil mist, and no new member is particularly required for this purpose. Although only one end side is shown in FIG. 4, a fixed support shaft 100 may be provided at both ends to support the motor rotating shaft 110, thereby making it a two-shaft type. In this case, if the hollow support shaft is used as it is, oil mist suction becomes easy.

Although the motor of the present invention has been described based on the illustrated embodiments, the present invention is not necessarily limited to these examples. changes in the mechanical configuration and rotation control method, etc.
Furthermore, it goes without saying that various shapes and numbers of oil mist suction openings can be adopted as embodiments of the present invention without departing from the gist of the present invention.

[Brief explanation of drawings]

FIG. 1 is an external perspective view showing an embodiment of the present invention. FIG. 2 is a sectional view of a main part of the embodiment shown in FIG. 1. FIG. 3 is a partially enlarged view of the main part sectional view shown in FIG. 2. FIG. 4 is a partial sectional view showing a modification of the portion shown in FIG. 3. FIG. DESCRIPTION OF SYMBOLS 1... Rotation drive part, 2... Rotation driven body (rotating mirror), 3... Rotation detection part, 5... Fixed support shaft, 51
... bearing, 7 ... motor rotation shaft, 55 ... gas flow path, 55a, 55b ... opening.

Claims (1)

[Claims] 1. A motor having a rotating shaft 7, a bearing 51, and a fixed support shaft 5, in which the rotating shaft 7 has a motor rotor 12 and a rotating driven body 2 fixed thereto, and is hollow at least at both ends. A motor characterized in that a bearing 51 is disposed in the hollow part of the rotating shaft 7, and the fixed support shaft 5 is supported by the bearing 51 inserted into the hollow part of the rotating shaft 7. 2. The fixed support shaft 5 has a gas passage 55 extending in the axial direction within the shaft, and the openings 55a and 55b of the gas passage 55 are formed in the bearing 51.
The motor according to claim 1, wherein the motor is formed on both sides of the motor.