JP3652732B2 - motor - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a motor for rotating a recording disk or for rotating a mirror used in a laser beam printer.
[0002]
[Prior art]
The conventional motor is for driving the magnetic disk 14 as shown in FIG. 3, and is a fixed shaft type motor having a shaft screwed to the outer frame of the apparatus. A base 1 forming the outer frame A of the apparatus is provided with an annular recess 2, a stator 3 is fitted in the annular recess 2, and a lower end portion of the fixed shaft 5 is inserted into the center hole of the annular recess 2 by a nut 6. It is fixed to. A sleeve 9 is rotatably supported on the fixed shaft 5 via a pair of ball bearings 8, 8 ′ serving as bearing means, and a rotor magnet is arranged so that the lower outer periphery of the sleeve 9 faces the inner peripheral surface of the stator 3. 11 is fixed.
[0003]
A rotor hub 10, which is a rotating member, is fitted and fixed to the outer periphery of the sleeve 9, and the magnetic disk 14 is placed on the flange portion 12 that spreads on the lower outer periphery of the rotor hub 10.
[0004]
A cap 15 that covers the sleeve 9 and the ball bearing 8 is fitted and fixed to the upper end of the fixed shaft 5 by press fitting. The cap 15 includes a disk part 15b, an outer wall part 15c extending downward from the outer periphery of the disk part 15b, and an inner wall part 15a extending upward from the inner periphery. Since the outer wall portion 15c and the sleeve 9 are opposed to each other with a minute gap, the labyrinth seal structure 24 is formed, and the inner wall portion 15a is a portion where the cap 15 is attached to the fixed shaft 5. The labyrinth seal structure 24 prevents the outgas of the ball bearing 8 from flowing out. A magnetic fluid seal 16 is disposed below the ball bearing 8 'between the fixed shaft 5 and the sleeve 9 to prevent outgas and oil from flowing out.
[0005]
[Problems to be solved by the invention]
Although the motor has the above configuration, it has the following problems. That is, in the ball bearing 8, the lubricating oil in the bearing oozes out from the gap between the inner ring and the rolling element and propagates through the surface of the inner ring. The oil is transmitted to the disk chamber 20 through a gap 17 in which the cap 15 and the fixed shaft 5 are fitted, and the oil leaks to the inner surface of the outer frame A. If oil leaks into the disk chamber 20, it adheres to the surface of the disk 14, and a head (not shown) for reading and writing data may not operate normally.
[0006]
An object of the present invention is to solve such a conventional problem and to provide a highly reliable motor in which lubricating oil and outgas from a bearing are prevented from leaking out of the motor.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, in the motor of the present invention, the shaft member, the bearing means pivotally supporting the shaft member, and the axially outward of the bearing means are fitted on the end side of the shaft member. A ring-shaped sealing member that seals a gap between a fitting portion between the shaft member and the fitting member, and a radially inner portion of the motor. It is mounted in a state where it is fitted in a concave groove provided in the member, and the radially outer portion of the sealing member is in close contact with the fitting member by applying a force in the axial direction by the fitting member. It is characterized by that.
[0008]
Further, it is desirable that the fitting member forms a labyrinth seal structure close to the bearing means.
[0012]
[Action]
In the motor having the above-described configuration, since the sealing member that seals the gap between the fitting portions of the shaft member and the fitting member is mounted, the lubricating oil that has oozed out from the bearing means is the sealing member. You will not be able to enter the gap.
[0013]
Further, since the fitting member forms a labyrinth seal structure in the vicinity of the bearing means, the lubricating oil from the bearing means is formed with a structure that prevents oil from flowing out of the sealing member and the labyrinth seal structure. The
[0014]
Further, since the shaft member and the fitting member rotate, the lubricating oil that has oozed out from the bearing means also enters the gap by the sealing member even in the motor in which the shaft member and the fitting member rotate. There is nothing.
[0015]
Further, since the sealing member is made of an elastic material, it can be easily mounted and assembly is simplified. And since a high contact state can be maintained with respect to the fitting member and the shaft member, leakage of the lubricating oil from the bearing means can be prevented.
[0016]
Furthermore, since the sealing member is fitted in the concave groove provided in the shaft member, the sealing member is easily positioned at the time of mounting and is not displaced after mounting.
[0017]
【Example】
The present invention will be described below with reference to the drawings illustrating embodiments. FIG. 1 is a sectional view of a motor according to a first embodiment of the present invention. In the embodiments, the same reference numerals as those in the conventional example indicate the same or corresponding parts.
[0018]
In this figure, the point different from the conventional one is in the part relating to the upper ball bearing 8, the cap 15 as a fitting member, and the fixed shaft 5. That is, since the cap 15 is fitted and fixed to the fixed shaft 5 by press-fitting, there is a slight gap 17 between the fixed shaft 5 and the inner wall portion 15a. A sealing member 22 made of an annular elastic material (for example, rubber) is attached to the fixed shaft 5 at the lower end opening 17a of the gap 17 so as to seal the opening 17a. The fixed shaft 5 is provided with an annular groove 23 having a size enough to accommodate a part of the inner periphery of the sealing member 22 so that the sealing member 22 is not displaced. In addition, it is convenient for positioning because it is easy to position. Although the concave groove 23 has a substantially triangular cross section in the embodiment, it may have a different shape (for example, a substantially square cross section), or the cap 15 may be provided with the concave groove 23 in this case. It is preferable to attach a material having elasticity that spreads outward.
[0019]
Even if the lubricating oil from the ball bearing 8 oozes out and is transmitted from the upper end surface of the inner ring to the fixed shaft 5, the motor having the above-described configuration opens the lower end of the gap 17 between the inner wall portion 15a and the fixed shaft 5. Since the sealing member 22 is attached to the portion 17a, the oil does not enter the gap 17 any more. In this case, the sealing member 22 can be deformed by the elasticity of the material and can maintain an extremely high contact state with the opposing contact members (the fixed shaft 5 and the cap 15). The sealing member 22 may be a porous member that absorbs oil, such as cellulose, foamed resin, or foamed rubber. In this case, once the oil is absorbed, it does not move any further, so that the oil does not enter the gap.
[0020]
Therefore, the lower end opening 17a of the gap 17 can be substantially completely sealed. Furthermore, since the labyrinth seal structure 24 and the sealing member 22 are configured to prevent oil from flowing out, oil does not flow into the disk chamber 20.
[0021]
Next, FIG. 2 is a cross-sectional view of a second embodiment of the motor showing the present invention, which is used for in-vehicle electrical equipment. This is a shaft rotation type motor whose shaft rotates, and has a structure in which a substantially cylindrical bearing bush 31 is disposed on a base plate 32 as a stationary member. A rotating shaft 35 is rotatably supported inside the bearing bush 31 via a pair of ball bearings 34 and 34 '. A substantially bowl-shaped rotor (fitting member) 36 is fixed to the upper part of the rotating shaft 35 by press-fitting, and rotates together with the rotating shaft 35. The rotor 36 includes a peripheral wall portion 36 a and a mounting portion 36 b that couples the peripheral wall portion 36 a to the rotation shaft 35. An annular rotor magnet 37 is attached to the inner periphery of the peripheral wall portion 36 a, and is disposed outside the bearing bush 31. It faces the externally fitted stator 38.
[0022]
A sealing member 43 made of an annular elastic material (for example, rubber) is mounted on the rotating shaft 35 below the mounting portion 36b, and a gap 42 in a fitting portion between the mounting portion 36b and the rotating shaft 35 is formed. It is sealed. A part of the sealing member 43 is accommodated in the annular groove 35 a provided in the rotating shaft 35 so as not to be displaced. On the circuit board 39 of the base plate 32, the rotor position detecting means 40 is placed facing the rotor magnet 37 and slightly inside the rotor magnet 37. The magnetic field of the rotor magnet 37 is read to detect rotation. A resin bush 41 that receives the lower end of the rotating shaft 35 in the axial direction is attached to the open end 31 a below the bearing bush 31. A thin thrust plate 33 made of iron is disposed outside the bush 41.
[0023]
In the motor configured as described above, even if the lubricating oil oozes out from the ball bearings 34, 34 ′, the sealing member 43 is held in close contact with the rotor 36 and the rotating shaft 35, so the oil is put into the gap 42. Will not invade. Therefore, oil does not flow out of the motor through the gap 42.
[0024]
As mentioned above, although the Example of the motor according to this invention was described, this invention is not limited to this Example, A various change is possible without deviating from the scope of the present invention. For example, in the first embodiment, it is a motor for rotationally driving a magnetic disk, but it may be used for a motor provided with a polygon mirror used in a laser beam printer. The bearing means in the first and second embodiments are both ball bearings, but the same effect can be obtained even with bearing means such as a hydrodynamic bearing and a sleeve bearing.
[0025]
【The invention's effect】
Since the present invention is configured as described above, the following effects can be obtained. That is, since the gap at the fitting portion between the fitting member and the shaft member is sealed by the sealing member, the oil that has oozed out from the bearing means is prevented by the sealing member and does not enter the gap. In addition, when an elastic material is used for the sealing member, it can be easily mounted and assembled, and can maintain a high contact state with the fitting member and the shaft member. Intrusion can be prevented.
[0026]
Further, since the shaft member is provided with a concave groove and the sealing member is fitted in the concave groove, the fitting member is easy to position at the time of mounting and is not displaced. Further, since the fitting member forms a labyrinth seal structure with the bearing means and a part of the rotating member, the oil from the bearing means prevents the oil from flowing out twice between the sealing member and the labyrinth seal structure. A structure is realized. In addition, when an elastic material is used for the sealing member, it is possible to maintain a high contact state with the fitting member and the shaft member, and thus it is possible to prevent leakage of lubricating oil from the bearing means.
As described above, the motor of the present invention is realized with high reliability in which lubricating oil and outgas from the bearing means are prevented from leaking out of the motor.
[Brief description of the drawings]
FIG. 1 is an overall sectional view showing a first embodiment of a motor according to the present invention.
FIG. 2 is an overall sectional view showing a second embodiment of the motor according to the present invention.
FIG. 3 is an overall sectional view showing a conventional motor.
[Explanation of symbols]
5 Fixed shaft 8, 8 'Ball bearing 9 Sleeve 10 Rotor hub 15 Cap 17 Clearance 22 Sealing member

Claims (2)

A shaft member;
Bearing means pivotally supporting the shaft member;
In a motor comprising a fitting member fitted on the end side of the shaft member on the outer side in the axial direction of the bearing means,
An annular sealing member that seals the gap between the fitting portion of the shaft member and the fitting member is mounted with its radially inner portion fitted in a concave groove provided in the shaft member. And
A motor characterized in that a radially outer portion of the sealing member is in close contact with the fitting member by applying an axial force by the fitting member .   The motor according to claim 1, wherein the fitting member forms a labyrinth seal structure adjacent to the bearing means.

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