JPH1189198A - Capstan motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a rotor shaft in a capstan motor to prevent charging by providing a very low-priced constitution. SOLUTION: A housing 1 has conductive bearings 5 and 7 in a hollow portion 3 and a magnetic core 9 and a stator plate 11 are provided on the outer circumference thereof. A conductive rotor shaft 19 and a driving magnet 25 are fixed to a rotor yoke 17, and the rotor shaft 19 is pivoted by bearings 5 and 7 and protruded from the bearing 5. A spring 47 is fixed to the rotor shaft 19 in order to make a continuity with the bearing 5 and a pressure welding strip 47b provided on the spring 47 is disposed of along the outer circumference of the housing 1. The housing 1, including the pressure welding strip 47b, is inserted from the side of the bearing 5 into an insertion hole 29 of a supporting plate 27, the housing 1 is screwed to the supporting plate 27 so that the pressure welding strip 47b is caused to be pressure-welded to the supporting plate 27 in the insertion hole 29.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capstan motor, and more particularly, to a capstan motor that suppresses electrostatic charging due to rotational driving and the like.

[0002]

2. Description of the Related Art Conventionally, in a capstan motor, as shown in FIG. 6, for example, a pair of bearings 5 and 7 made of oil-less metal are coaxially fixed in a hollow portion 3 of a conductive housing 1. A magnetic core 9 and a stator plate 11 with an electronic circuit are screwed to the outer periphery of the housing 1 with screws 13, and a plurality of drive coils 15 are wound around the magnetic core 9, while a rotor shaft 19 supported on the rotation center of a rotor yoke 17. The bearings 7, 5
Through the housing 1 so that the rotor shaft 1
9, the thrust receiver 21 holds down the bearing 5 and the rotor shaft 1
9 is positioned, an annular drive magnet 25 is arranged inside the side wall 23 of the rotor yoke 17 so as to face the tip of the magnetic core 9, and the rotor shaft is inserted into an insertion hole 29 provided in a conductive support plate 27 such as a chassis of the device. 19 from the tip side
, A screw 31 is screwed into the housing 1 from the support plate 27 side, and the screw 31 is supported by the support plate 27. Reference numeral 33 in FIG.
7 is a pulley attached to the back side of FIG.

In such a capstan motor, a plurality of drive coils 15 are switched and energized by an electronic circuit (not shown) provided on the stator plate 11 to rotate the rotor yoke 17 and to protrude downward from the housing 1 in the figure. A magnetic tape (not shown) of, for example, a VCR is pressed against the shaft 19, and the magnetic tape is caused to travel, while a pulley 33 drives a rubber belt (not shown).

However, in such a capstan motor, when the magnetic tape runs or when the pulley 33 slides on the rubber belt, the rotor shaft 19 is easily charged with static electricity. Since there is a concern that an undesired situation may occur from above, the housing 1 is formed by die-casting from a conductive metal material, for example, an aluminum material, and the housing 1 is supported on a support plate 27 as a chassis of the electronic device in a grounded state. ,
The static electricity of the rotor shaft 19 is transferred to the support plate 2 via the housing 1.
I missed to 7.

[0005]

However, in the above-described capstan motor, when the housing 1 is formed of a conductive metal material, it is difficult to reduce the manufacturing cost of the housing 1 and the obstacle to the reduction of the manufacturing cost of the entire capstan motor. There is a disadvantage that it is easy to become. Although there are attempts to reduce the manufacturing cost by molding the housing 1 with a carbon-containing synthetic resin or the like, even if the housing 1 is molded with a carbon-containing synthetic resin, the cost cannot be significantly reduced. 1 has a drawback that the conductivity tends to be insufficient and static electricity cannot be reliably discharged.

SUMMARY OF THE INVENTION The present invention has been made to solve such a conventional disadvantage, and an object of the present invention is to provide a capstan motor in which charging of a rotor shaft is prevented by an inexpensive and simple structure.

[0007]

SUMMARY OF THE INVENTION In order to solve such a problem, the present invention provides a conductive support on a stator side, a non-conductive housing having a conductive bearing and fixed to the support. A conductive rotor shaft rotatably supported by the bearing, and a conductive spring piece sandwiched between an end face of the bearing and a holding member of the bearing and at least in contact with the bearing and having an end portion pressed against the supporting portion; And

Further, according to the present invention, the outer periphery of the housing is fitted into an insertion hole provided in a support portion of the housing, the spring piece is inserted into the rotor shaft to make contact with a bearing, and the end is inserted into the insertion hole. In this case, it is preferable to adopt a configuration in which the support portion is pressed against the support portion. Further, in the present invention, it is preferable that a portion of the spring piece inserted into the rotor shaft has a spring property.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. Note that the same reference numerals are given to portions common to the conventional example.

FIG. 1 is a longitudinal sectional view (partly shown in side view) showing one embodiment of a capstan motor according to the present invention.
In FIG. 1, a housing 1 is formed by molding a general non-conductive synthetic resin into a substantially cylindrical shape, and a pair of conductive bearings 5 made of oilless metal are provided at both ends in a hollow portion 3. 7 are coaxially fixed at intervals.

As shown in FIG. 2A which is a bottom view as viewed from the lower side of FIG. 1 and FIG. 2B which is a plan view as viewed from the upper side of FIG. A screw hole 37 is formed in the collar portion 35 in an annular shape so as to penetrate the hollow portion 3 at an equal angle of, for example, 120 °. Both sides of the flange 35 of the housing 1 partially project and become convex portions 39 and 41, and are thickened in the axial direction. The screw holes 43 penetrate the housing 1 so as to penetrate the housing 1. It is formed in an annular shape.

The screw holes 43 and the convex portions 39 and 41 are formed at an equal angle of, for example, 120 ° around the hollow portion 3 and at a position shifted from the screw hole 37 by, for example, 60 °. However, the positions where the screw holes 37 and 43 and the convex portions 39 and 41 are formed are arbitrary. The stator plate 11 made of a magnetic material and the magnetic core 9 are placed on the outer periphery of the housing 1 so that the stator plate 11 and the magnetic core 9 are overlapped with the flange 35 of the housing 1 therebetween. The magnetic core 9 and the stator plate 11 are fixed to the housing 1 by being screwed into the stator plate 11 through the screw holes 37 of the flange 35.

The magnetic core 9 has a concave portion corresponding to the convex portion 41, and an electronic circuit for switching and energizing a drive coil 15 described later is formed on the stator plate 11.
The illustration is omitted. The magnetic core 9 has a plurality of salient pole teeth 9a radially and integrally, and the plurality of salient pole teeth 9a
A plurality of drive coils 15 are wound separately, and both ends of the drive coil 15 are connected to an electronic circuit of the stator plate 11.

The support plate 27 is a conductive support portion, for example, as a chassis or a frame of an electronic device, and
And has an insertion hole 29 slightly larger in diameter than the outer periphery of the housing 1. That is, the housing 1
1 is inserted through the insertion hole 29 (the lower part in FIG. 1) so that the projection 39 contacts the support plate 27 and the support plate 2
The screw 31 is screwed into the screw hole 43 of the housing 1 from the side 7 to be fixedly supported on the support plate 27. Needless to say, the support plate 27 has a hole into which the screw 31 is screwed.

The rotor yoke 17 is formed in a cup shape from a magnetic material, for example, a steel plate, and one end of the conductive rotor shaft 19 is press-fitted and supported in a support cylinder 45 formed at the center of rotation. The rotor shaft 19 is supported by being penetrated through the housing 1 so as to pass through the bearings 7, 5 and the like.

A spring piece 47 (see FIG. 3), a metal C-shaped washer 49 and a thrust receiver 21 made of synthetic resin are fitted into the rotor shaft 19 outside the bearing 5. The portion of the rotor shaft 19 into which the thrust receiver 21 is fitted has a small diameter, making it difficult for the thrust receiver 21 to come off. At the same time, the thrust receiver 21 is connected via the washer 49 while ensuring smooth rotation of the rotor shaft 19. The spring piece 47 is held down. The washer 49 is useful for the purpose of reliably suppressing the spring piece 47, but is not essential.

As shown in FIG. 3, the spring piece 47 includes a ring portion 47a and an elongated press-contacting piece 4 projecting in a plane from the outer periphery thereof, bending in an L-shape from the middle thereof, and further expanding its tip into a C-shape.
7b, the ring portion 47a is fitted into the rotor shaft 19 and supported. In addition, the spring piece 47 is electrically connected to the bearing 5, and the pressure contact piece 47 b extends along the outer periphery of the housing 1 to the insertion hole 29 of the support plate 27 and is pressed against the inner surface of the insertion hole 29 to be electrically connected. Is electrically conductive. Therefore, it is preferable that at least a part of the bearing 5 protrude from the lower end surface of the housing 1 and come into contact with the spring piece 47.

An annular drive magnet 25 is fixed inside the side wall 23 of the rotor yoke 17, and the magnetic core 9
Of each salient pole tooth 9a. A pulley 33 is fixed to the back side (upper side in FIG. 1) of the rotor yoke 17 so as to be fitted to the support cylinder 45, and a rotational force can be transmitted to another mechanism (not shown) by, for example, putting a belt over the pulley 33. It has become. The stator 51 is formed by the support plate 27, the housing 1, the stator plate 11, the magnetic core 9, the drive coil 15, the spring piece 47, and the like, and the rotor yoke 17, the rotor shaft 19, the drive magnet 25, and the like form a rotor. 53 are formed.

In this capstan motor, for example, a magnetic core 9 and a stator plate 11 are screwed to a housing 1 provided with bearings 5 and 7 with screws 13, and salient pole teeth 9a of the magnetic core 9 are provided.
A plurality of drive coils 15 are wound around the housing 1 and connected to an electronic circuit of the stator plate 11, and the housing 1 is penetrated so that the rotor shaft 19 of the rotor yoke 17 passes through the bearings 7, 5 and the like. Spring piece 4
7, the washer 49 and the thrust receiver 21 are fitted and the spring piece 47 is pressed into contact with the bearing 5, and the housing 1 is passed through the insertion hole 29 of the support plate 27 from the bearing 5 side, including the elongated pressure contact piece 47b of the spring piece 47. When the screw 31 is screwed into the screw hole 43 of the housing 1 from the support plate 27 side, the pressure contact piece 47b of the spring piece 47 is pressed against the support plate 27 in the insertion hole 29, and the rotor shaft 19 is brought into contact with the bearing 5 and the spring piece. 47
And is completed in a state of being electrically connected to the support plate 27 through the.

In such a capstan motor, when a plurality of drive coils 15 are switched and energized to rotate the rotor yoke 17 and a magnetic tape (not shown) is brought into pressure contact with the rotor shaft 19 and run, the rotor shaft 19 Although static electricity is easily generated, the bearing 5 and the washer 49 or the thrust receiver 21 are electrically connected to the conductive bearing 5 in a state where the conductive spring piece 47 is electrically connected to the conductive bearing 5.
Since the support shaft is cantilevered and is electrically connected to the conductive support plate 27, the static electricity of the rotor shaft 19 is supported via the bearing 5 and the spring piece 47 or directly from the rotor shaft 19 via the spring piece 47. 27, it is difficult for the rotor shaft 19 to be charged with static electricity. Therefore, the generation of noise can be suppressed low, and a capstan motor preferable from the viewpoint of safety can be obtained.

A housing 1 for supporting the bearings 5 and 7
Can be formed inexpensively by, for example, a general non-conductive synthetic resin, while the spring piece 47 can be formed inexpensively by punching and bending from a resilient conductive plate such as a stainless material such as SUS304CSP. From
It is much cheaper than forming the housing 1 with a conductive metal material, and the manufacturing cost of the capstan motor can be greatly reduced. Moreover, since the elongated press contact piece 47b of the spring piece 47 extends along the outer periphery of the housing 1, if the housing 1 is passed through the insertion hole 29 of the support plate 27 from the spring piece 47 side, including the elongated press contact piece 47b. The spring piece 47 can be automatically conducted to the support plate 27, so that the assembly is simple and the characteristics are stable.

Further, the ring portion 47a of the spring piece 47 is fitted on the rotor shaft 19, and the washer 49 and the thrust receiver 21 are fitted.
Is inserted into the rotor shaft 19, the spring piece 47 is attached to the rotor shaft 1.
9 and electrical continuity with the bearing 5 is ensured, so that a fixing member such as a screw or an adhesive for arranging and fixing the spring piece 47 is not required, and the configuration of the conventional capstan motor is significantly changed. Since the spring piece 47 can be arranged without performing the above, there is an advantage that the manufacturing is simple and the cost can be reduced also from this point.

By the way, in the above-described embodiment, the pressure contact piece 47 is formed from a part of the ring portion 47a forming the spring piece 47.
b was extended one piece, but as shown in FIG.
The object of the present invention can be achieved even if the press contact pieces 47b are extended from a plurality (for example, two places) of the ring portion 47a and the press contact pieces 47b are pressed into the insertion holes 29 of the support plate 27. The number of press contact points with the contact increases, and more reliable electric contact can be realized. Also, in the case of the shape of FIG. 3 as an example, the ring portion 47a is formed to be bent so as to protrude from the inner diameter portion side as shown in FIG. 5, and the bent portion has an axial spring property. By doing so, the ring portion 47a is strongly pressed against the bearing 5, and the contact with the bearing 5 can be further ensured. The same applies to the spring piece shape of FIG.

The configuration in which the ring portion 47a is provided with an axial spring property is not limited to an example in which the inner diameter side of the ring portion 47a is bent and projected in a convex shape. Although not shown, if a shape similar to a torsionally bent C-shaped spring washer or a toothed washer having a plurality of teeth bent and protruded on the outer periphery or the inner periphery is used, contact with the bearing 5 can be further ensured. Things. However, the capstan motor of the present invention is not limited to the configuration in which the pressure contact piece 47b of the spring piece 47 is pressed against the inner surface of the insertion hole 29 of the support plate 27. The object can be achieved by a configuration in which the spring piece 47 is pressed against the lower surface.
The object of the present invention can be achieved by a structure supported at least in a state of being in electrical contact with the bearing 5 in addition to the fitting into the bearing 9.

Further, the bearings 5 and 7 are not limited to oil-less metals, but can be implemented by known conductive bearings such as ball bearings. Further, the fixing of the magnetic core 9 and the stator plate 11 to the housing 1 and the fixing of the housing 1 to the support plate 27 are not limited to screws, but may be, for example, eyelets or other known fixing structures.

The basic configuration of the capstan motor according to the present invention is not limited to the configuration in which the driving magnet 25 is circumferentially opposed to the outer periphery of the leading end of the magnetic core 9 as described above, but the configuration in which the driving coil and the driving magnet are face-to-face. Other known configurations can be used.

[0027]

As described above, the capstan motor of the present invention has a conductive bearing, a non-conductive housing fixed to a conductive support on the stator side, and a conductive rotor shaft supported by the bearing. Since the conductive spring piece is sandwiched between the bearing and the pressing member, at least the bearing is brought into contact with the bearing and the end is pressed against the supporting portion, so that the rotor shaft is easily electrically connected to the supporting portion. And the housing can be formed of a non-conductive general synthetic resin. Therefore, the manufacturing cost of the housing becomes low, and the spring piece as the conductive member becomes extremely inexpensive.
The manufacturing cost can be greatly reduced and the configuration is simple. Also, a configuration in which the outer periphery of the housing is fitted into the insertion hole provided in the support portion, the spring piece is inserted into and supported by the rotor shaft to make contact with the bearing, and the end is inserted into the insertion hole and pressed against the inner surface. By fitting the outer periphery of the housing into the through-hole of the support portion, the spring piece can be automatically and reliably conducted to the support portion, so that the assembly is simple and the characteristics are stable. Further, the configuration in which the portion of the spring piece that is inserted into the rotor shaft has resiliency has the advantage that the contact with the bearing can be further ensured.

[Brief description of the drawings]

FIG. 1 is a vertical cross-sectional view (a cross-sectional view taken along a line II in FIG. 2A, showing a partial side view) of an embodiment of a capstan motor according to the present invention.

FIG. 2 is a schematic bottom view (A) and a schematic plan view (B) showing a housing in the capstan motor of FIG.

FIG. 3 is a perspective view showing a spring piece in the capstan motor of FIG. 1;

FIG. 4 is a perspective view showing another example of a spring piece used for the capstan motor of the present invention.

FIG. 5 is a sectional view showing another example of a spring piece used for the capstan motor of the present invention.

FIG. 6 is a longitudinal half sectional view (partly shown in side view) showing a conventional capstan motor.

[Description of Signs] 1 Housing 3 Hollow portion 5, 7 Bearing (oil-less metal) 9 Magnetic core 9a Salient pole teeth 11 Stator plate 13, 31 Screw 15 Drive coil 17 Rotor yoke 19 Rotor shaft 21 Thrust support (suppression member) 23 Side wall 25 Drive magnet 27 Support plate (support portion) 29 Insertion hole 33 Pulley 35 Collar portion 37, 43 Screw hole 39, 41 Convex portion 45 Support cylinder 47 Spring piece 47a Ring portion 47b Pressure contact piece 49 Washer (holding member) 51 Stator portion 53 Rotor part

Claims (3)

[Claims] 1. A conductive support portion on a stator side, a non-conductive housing having a conductive bearing and fixed to the support portion, a conductive rotor shaft supported by the bearing, and an end face of the bearing And a conductive spring piece sandwiched between a holding member of the bearing and at least being in contact with the bearing and having an end pressed against the supporting portion. 2. The housing has an outer periphery fitted into an insertion hole provided in the support portion, and the spring piece is inserted into the rotor shaft to contact the bearing, and the end is inserted into the insertion hole. 2. The capstan motor according to claim 1, wherein the capstan motor is rarely pressed against the support portion. 3. The capstan motor according to claim 2, wherein the spring piece has a spring property at a portion inserted into the rotor shaft.