JPH0321188Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a sealed shaft fixing mechanism for a motor having, for example, a gas bearing, in which the distance between a fixed shaft and a rotating shaft (rotor) is set to be extremely small.

[Prior Art] Conventionally, gas bearings have been used in motors where the distance between the fixed shaft and the rotating shaft is extremely small, such as gas bearings used in scanning motors for polygon mirrors used for light beam scanning in laser beam printers. must maintain a high level of surface treatment and dimensional accuracy.

These minute gaps are generally 20 μm or less, and therefore, vibrations and shocks during transportation and movement can cause the fixed shaft and rotating shaft to come into contact, damaging each other's surfaces and causing rotational damage. This results in disadvantages such as a decrease in accuracy and a significant deterioration of motor characteristics.

Further, even if minute foreign matter enters the inside of the motor housing or the space between the shafts, the characteristics of the motor will be significantly impaired.

[Purpose of invention]

In view of the above-mentioned disadvantages, the purpose of this invention is to
The motor's sealed shaft fixing mechanism is compact and strong against vibrations and shocks that occur during transportation and movement, and there is little risk of foreign objects entering during use. The objective is to minimize the increase in cost and the complexity of work.

[Structure of the idea]

The object of the present invention described above is to provide a lock shaft which is fitted on one surface of a housing above an extension of the axes of a fixed shaft and a rotating shaft, and which is supported so as to be movable up and down. The seat provided at the tip of the shaft inside the motor casing is made of an elastic material such as rubber or plastic to prevent damage to the contact surface with the rotating shaft and the contact surface with the inner surface of the motor casing. A ring-shaped fixing member is installed, and the
This is achieved by moving the lock shaft up and down to lock and release the rotation shaft.

[Example of idea]

A preferred embodiment of the present invention will be described below.

FIG. 1 is a sectional view showing an embodiment of the present invention, and shows a state in which the locking shaft and the fixing member are lowered and the rotating shaft is fixed (locked) during transportation or movement, for example.

FIG. 2 is a cross-sectional view of an embodiment of the present invention, showing the state in use, that is, the unlocked state.

Reference numeral 1 denotes a lock shaft, which has a threaded portion on its shaft, a recessed portion for a screwdriver or hexagonal wrench on its top portion 1a, and a seat portion 1b on its lower tip. An annular fixing member 2 for cushioning is provided on the edge 1c.

The fixing member 2 is made of an elastic material such as rubber and has a dense structure, and blocks air circulation.

3 is a rotating shaft (rotor), 4 is a fixed shaft, and the axial gap between them is generally 20 μm due to the buoyancy provided by a permanent magnet (not shown). The interval is set to be extremely small as follows.

Reference numeral 5 denotes a housing, and a spring 6 is disposed between a disk portion 1d provided around the top of the lock shaft 1 and the top surface of the housing, and urges the lock shaft 1 upward. It also has the effect of preventing loosening.

In FIG. 1, the lock shaft 1 is being rotated in the direction of the housing 5, and the fixing member 2 held at the edge 1c of the seat portion 1b disposed at the lower tip pushes the rotation shaft 3. Thus, the rotating shaft 3 is fixed in contact with the fixed shaft 4.

Since the rotating shaft 3 is fixed in contact with the fixed shaft 4, even during transportation or movement, collision, contact, or sliding with each other is unlikely to occur, and damage to the surfaces of each other is difficult.

Due to the elasticity of the fixing member 2, the seat portion 1b of the lock shaft 1 and the rotating shaft 3 can be pressed and fixed so that metal-to-metal contact does not occur.

Therefore, external vibrations and shocks are buffered and attenuated by the elasticity of the fixed member 2, and are not directly transmitted to the rotating shaft 3 or the fixed shaft 4.

Fig. 2 shows the state of the motor in use; when the screw is rotated in the loosening direction, the lock shaft 1 moves upward without delay because it is energized by the spring 6, and therefore The fixing member 2 provided on the seat portion 1b is detached from the rotating shaft 3.

Since the rotating shaft 3 is no longer pressed from above, it floats due to the buoyancy caused by the magnetic force etc. mentioned above.
A predetermined gap is set between the rotating shaft 3 and the fixed shaft 4.

In addition, since the fixing member 2 is in close contact with the inner surface of the housing 5, it prevents foreign matter from entering together with air from outside the motor.

With this arrangement, the motor will be used after this and will not have any problems when starting to rotate.

Furthermore, when the motor is rotating, the fixed member 2
Since it is in close contact with the inner surface of the casing 5, it damps the vibration of the casing 5 caused by the rotation of the motor, thus also serving as vibration and sound insulation.

[Other Examples]

In addition, especially when the motor rotates at high speed, such as the motor that drives the rotation of the polygon scanner of a laser beam printer, the temperature inside the casing increases, which may have a negative effect on the motor characteristics. will arise.

At this time, if the fixing member 2 is made of a material such as rubber that is structurally dense and does not have any ventilation holes, air cannot be taken in. This results in a decrease in cooling efficiency.

In other embodiments of the present invention, the fixing member 2 may be provided with minute ventilation holes, or a sponge-like filter member may be provided integrally. Air can be taken in from outside the motor through the gap existing in the portion 5a, thereby preventing a decrease in cooling efficiency.

In addition, the fine ventilation holes in the fixing member 2 are designed to have a filter effect during intake, which is intended to prevent foreign substances from entering or entering the motor. It's even better because you can do the inhalation without any loss of effectiveness.

Further, in this embodiment, the seat portion 1b is provided at the tip of the lock shaft 1, and a securing member for cushioning is provided. There is no problem even if an elastic fixing part (material) is directly placed on the part).

Further, in this embodiment, the lock shaft 1 is provided with a spring 6 that urges it upward, but other methods may be used to prevent the lock shaft 1 from loosening.

[Effect of idea]

As mentioned above, by implementing the present invention, the gap between the stationary shaft and the rotating shaft is so small that the surface could be damaged by external shocks and vibrations during transportation or movement. It is possible to obtain a closed shaft fixing mechanism for a motor, which eliminates the conventional disadvantages and reduces the possibility of foreign matter entering from the outside when the motor is in use (rotating).

Another advantage is that by providing the fixing member with a ventilation effect and a filter effect, air can be taken in from the outside when the motor is rotating, which improves cooling efficiency. A mechanism is obtained.

Moreover, in the present invention, since the above-mentioned mechanism can be achieved by the configuration of the lock shaft 1 and the fixing member 2, the device is small and lightweight, and even when working, as in the embodiment, the threaded portion 1a It suffices to simply rotate the lock shaft 1.

Furthermore, since only one fixing member is required, there is little increase in man-hours, and in terms of workability,
It is extremely easy to just fit it onto the seat portion 1b of the lock shaft 1.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view showing an embodiment of the present invention when it is being moved, and FIG. 2 is a schematic cross-sectional view showing the same embodiment when it is in use. 1... Lock shaft, 1a... Top, 1b... Seat, 1c... Edge, 2... Fixed member, 3... Rotating shaft, 4... Fixed shaft, 5... Housing, 6... Spring.

Claims (1)

[Claims for Utility Model Registration] (1) In a motor having an outer rotor type gas bearing in which a rotating shaft is disposed inside a housing so as to cover a fixed shaft from above, the upper surface of the housing of the motor a lock shaft that is fitted into the rotary shaft and movable up and down on the axis of the rotary shaft and the fixed shaft, and that has a seat at the tip inside the housing of the motor; an annular fixing member disposed on the seat of the locking shaft, and when the rotating shaft is fixed by lowering the lock shaft, the rotating shaft is pressed by the fixing member and the fixing shaft is fixed. and when the rotating shaft is released from the fixed shaft with the lock shaft raised,
A closed shaft fixing mechanism for a motor, wherein the fixing member is in contact with an inner surface of the casing of the motor. (2) The closed shaft fixing mechanism for a motor according to claim 1, wherein the fixing member has minute ventilation holes to allow ventilation.