JP3240122B2 - Capstan motor - Google Patents

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.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 4, for example, a capstan motor has a pair of bearings 5, 7 made of oilless metal fixed coaxially in a hollow portion 3 of a conductive housing 1. Screws 17 are screwed into the screw holes 15 of the housing 1 from the conductive support plate 13 side of the equipment chassis or the like, and the housing 1 is supported on the support plate 13 so that a part thereof protrudes. Core 1 around the outer circumference
9 is screwed into the screw hole 21 provided in the magnetic core 19.
3 is fixed to the housing 1 by screwing, and a plurality of drive coils 25 are formed on the magnetic core 19, while the rotor shaft 29 supported by the rotation center of the rotor yoke 27 is passed through the bearings 7, 5 and the like. And the housing 1 is penetrated and positioned by the washers 31 and 33.
A configuration is known in which an annular drive magnet 35 is disposed inside the side wall 27 a of the magnetic core 7 and faces the tip of the magnetic core 19.

[0004] Reference numerals 37 and 39 in FIG. 4 denote a stator plate and a circuit board fixed between the support plate 13 and the magnetic core 19, for example, to the housing 1. Reference numeral 41 is attached to the back side of the rotor yoke 27. Pulley. In such a capstan motor, a plurality of drive coils 25 are switched and energized by an electronic circuit (not shown) formed on a circuit board 39 to rotate the rotor yoke 27 so as to rotate the rotor yoke 27 so that the rotor shaft 29 projects downward from the housing 1 in FIG. For example, a magnetic tape (not shown) of a VCR is brought into pressure contact with the magnetic tape, and the rubber tape (not shown) is driven by a pulley 41 while running the magnetic tape.

In such a capstan motor, static electricity is easily charged on the rotor shaft 29 when the magnetic tape is run or when the pulley 41 slides on the rubber belt. 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 in a grounded state on a support plate 13 as a chassis of the electronic device. In addition, the static electricity of the rotor shaft 29 is released to the support plate 13.

[0005]

However, in the above-described capstan motor, if the housing 1 is formed from 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. However, housing 1
There is an attempt to reduce the manufacturing cost by molding the resin 1 with a carbon-containing synthetic resin or the like. However, even if the housing 1 is molded with a carbon-containing synthetic resin, the cost cannot be significantly reduced. However, there is a drawback that static electricity 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 has a conductive support portion on the stator side and a conductive bearing, and is fixed to the support portion by a conductive fixing member. It has a non-conductive housing, a conductive rotor shaft rotatably supported by a bearing thereof, and a conductive wire spring which is in contact with the bearing and has one end connected to the fixed member.

In the present invention, a configuration is also possible in which the wire spring is sandwiched between an end surface of the bearing and a holding member of the bearing. Further, in the present invention, a coil spring is used as the wire spring, and the coil portion is fitted to the rotor shaft so as to be press-fitted between the bearing and the holding member, and one end of the coil portion is pressed against the fixed member. Good.

[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, and a conductive washer 9 is fitted and fixed on the lower side in FIG.
The bearing 5 is prevented from being worn by contact with a washer 31 to be described later, and the conductive washer 11 is fitted and fixed to the upper side in FIG.
To prevent the bearing 7 from being worn by contact with a washer 33 described later.

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.
Are formed in an annular shape so as to penetrate the housing 1 at an equal angle, and convex portions 45 and 47 are formed around the screw holes 15 so as to be thick in the axial direction.
45, that is, the space between the adjacent convex portions 47, 47 becomes thinner in the axial direction to form a flange portion 49, and the screw hole 21 is formed in the flange portion 49 at an equal angle of, for example, 60 ° with respect to the screw hole 15. It is formed in an annular shape so as to penetrate to the shifted position.
However, the positions where the screw holes 15 and 21 are formed are arbitrary.

The support plate 13 is a conductive support portion, for example, as a chassis or a frame of an electronic device.
Is inserted. The housing 1 is
A part (lower part in FIG. 1) is inserted through the insertion hole 51 so that the projection 45 contacts the support plate 13, and the conductive screw 17 is screwed into the screw hole 15 from the support plate 13 side. The support plate 1 is electrically connected to the support plate 13.
3 fixedly supported. The support plate 13 has a screw 1
Needless to say, a hole for screwing 7 is formed.

Between the support plate 13 and the flange 49 of the housing 1, a stator plate 37 and a circuit board 39 made of a magnetic material are overlaid on, for example, the flange 49 and fixed thereto. The stator plate 37 and the circuit board 39 can be fixed to the support plate 13 by appropriate means. On the outer periphery of the housing 1, a magnetic core 19 having a plurality of salient pole teeth 19 a radially and integrally disposed is arranged so as to be mounted on a flange 49, and a magnetic hole is formed in a screw hole 21 provided in the flange 49. A screw 23 is screwed in from the core core 19 side to be fixed to the housing 1.

The magnetic core 19 has a recess corresponding to the projection 47 and a hole into which the screw 23 is screwed. A plurality of drive coils 25 are wound around the plurality of salient pole teeth 19a of the magnetic core 19 in a divided manner.
5 are connected to the circuit board 39 at both ends.

The gap 43 between the bearing 7 fixed to the housing 1 and the washer 11 is provided with, for example, phosphor bronze or SUS304.
A conductive wire spring 53 made of CSP and having good elasticity is elastically held. As shown in FIG. 3, the wire spring 53 has a diameter slightly larger than the outer diameter of a rotor shaft 29 described later.
And a coil 53a wound one or two turns with a diameter slightly smaller than the outer diameter of the coil 53a. An end of the coil 53a is extended and bent in the shape of a crank along the way, and is L-shaped along the winding axis of the coil 53a. The coil part 53a is elastically sandwiched between the bearing 7 and the washer 11, and the connection piece 53b is inserted into the screw hole 15 and pressed against the tip end surface of the screw 17. I have.

That is, the wire spring 53 is cantilevered between the bearing 7 and the washer 11 in a state where the coil portion 53a is electrically connected to the bearing 7, and the connection piece 53b is electrically connected to the screw 17. It is pressed in a state. Although not described in detail, a groove is provided in the housing 1 between the bearing 7 and the washer 11, that is, at a position corresponding to the gap 43, and a wire spring 53 is provided.
When the connection piece 53b extending from the coil portion 53a is led out through the groove, the positioning of the wire spring 53 is accurate and the derivation is easy.

The rotor yoke 27 is formed in a cup shape from a magnetic material, for example, a steel plate, and one end of the conductive rotor shaft 29 is press-fitted and supported by a support cylinder 55 formed at the center of rotation. When the rotor shaft 29 is rotatably supported by penetrating the housing 1 so as to pass through the bearings 7, 5, etc., the tip thereof extends to protrude from the housing 1.

The washer 31 has, for example, a C-shape fitted to the small-diameter portion of the rotor shaft 29 and suppresses the washer 9 in contact with the bearing 5, and the washer 33 fitted to the rotor shaft 29 has a The washers 11 are suppressed while being in contact with each other, but each of the washers 9 and 11 is suppressed so as to ensure smooth rotation of the rotor shaft 29.

An annular drive magnet 35 is fixed inside the side wall 27a of the rotor yoke 27, and faces the tip of each salient pole tooth 19a of the magnetic core 19 at a slight interval. Back side of rotor yoke 27 (upper side in FIG. 1)
, The pulley 41 is fixed so as to be fitted to the support cylinder 55, and a rotational force can be transmitted to another mechanism (not shown) by, for example, putting a belt over the pulley 41.

The stator portion 57 is formed by the support plate 13, the housing 1, the stator plate 37, the circuit board 39, the magnetic core 19, the drive coil 25, the wire spring 53 and the like, and the rotor yoke 27, the rotor shaft 29,
The rotor portion 59 is formed by the drive magnet 35 and the like.

In such a capstan motor, when a plurality of drive coils 25 are switched and energized to rotate the rotor yoke 27 and run with the magnetic tape (not shown) pressed against the rotor shaft 29, the rotor shaft 29 Although static electricity is easily generated, the conductive wire spring 53 is cantilevered between the bearing 7 and the washer 11 in a state of being electrically connected to the conductive bearing 7 and electrically connected to the conductive screw 17. Since the screw 17 is also in conduction with the conductive support plate 13, static electricity of the rotor shaft 29 escapes to the support plate 13 via the bearing 7, the wire spring 53 and the screw 17, and the rotor shaft 29 is pressed. Is hardly 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 using, for example, a general non-conductive synthetic resin, while the wire spring 53 can
And a coil portion 53a wound several turns,
a 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. In addition, since the coil portion 53a is elastically held between the bearing 7 and the washer 11, and the connecting piece 53b is pressed against the screw 17 by utilizing the spring property of the wire spring 53 itself, the gap between the wire spring 53 and the screw 17 is increased. The electrical contact of is ensured.

Further, since the coil portion 53a may be accommodated in the small gap 43 between the bearing 7 and the washer 11 so as to overlap, a fixing member such as a screw or an adhesive for arranging and fixing the wire spring 53 is required. In addition, since the space for accommodating the wire spring 53 can be secured without changing the configuration of the conventional capstan motor much, there is an advantage that the manufacturing is simple and the cost can be reduced also from this point.

However, the wire spring 53 is not limited to the structure having the coil portion 53a and the bent connection piece 53b, as long as the wire spring 53 electrically connects the bearing 7 to the support plate 13. A structure in which one end is electrically connected to the outer peripheral surface of the bearing 7 (between the housing 1) or the end surface of the bearing 7 and the other end is electrically connected to the screw 17 is also possible. It is.

In the above-described embodiment, the wire spring 53 is configured to be in electrical contact with the bearing 7.
A configuration in which the bearing 5 is electrically contacted is also possible. In the present invention, when there are a plurality of bearings, the object of the present invention can be achieved by contacting any of the bearings. Further, the bearings 5 and 7 are not limited to oil-less metals, and can be implemented by known conductive bearings such as ball bearings. The member for supporting and fixing the housing 1 to the support plate 13 and electrically connecting the housing 1 is not limited to a screw, and may be, for example, an eyelet or a known conductive fixing member.

The basic configuration of the capstan motor according to the present invention is not limited to the configuration in which the driving magnet 35 is circumferentially opposed to the outer periphery of the leading end of the magnetic core 19 as described above, but the configuration in which the driving coil and the driving magnet face each other. Other known configurations can be used.

[0027]

As described above, the capstan motor of the present invention has a conductive bearing and a non-conductive housing fixed to a conductive support on the stator side by a conductive fixing member.
Since the conductive rotor shaft is supported on the bearing and the conductive wire spring is electrically connected to the bearing and one end is electrically connected to the fixing member, the rotor shaft is electrically connected to the supporting portion. And the housing can be formed of a non-conductive general synthetic resin, while the wire spring as the conductive member is extremely inexpensive, so that the configuration is simple and the manufacturing cost is greatly reduced. Can be reduced. In the configuration in which the wire spring is sandwiched between the end face of the bearing and the holding member, the wire spring can be stored in a state in which the wire spring is in contact with the bearing without much changing the configuration of the conventional capstan motor. From this point, the manufacturing cost can be reduced. further,
In a configuration in which a coil spring is used as the wire spring and the coil portion is fitted on the rotor shaft, the coil portion is press-fitted between the bearing and the holding member, and one end of the wire is pressed against the fixed member. The connection support is more reliable and the reliability is higher.

[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 plan view showing a housing in the capstan motor of FIG.

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

FIG. 4 is a longitudinal half sectional view (partly shown in side view) showing a conventional capstan motor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Housing 3 Hollow part 5, 7 Bearing (oil-less metal) 9, 31, 33 Washer 11 Washer (holding member) 13 Support plate (support part) 15, 21 Screw hole 17, 23 Screw 19 Magnetic core 19a Salient pole teeth Reference Signs List 25 Drive coil 27 Rotor yoke 27a Side wall 29 Rotor shaft 35 Drive magnet 37 Stator plate 39 Circuit board 41 Pulley 43 Gap 45, 47 Convex part 49 Collar part 51 Insertion hole 53 Wire spring 53a Coil part 53b Connection piece 55 Support cylinder 57 Stator part 59 Rotor part

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H02K 21/00 H02K 5/08 H02K 5/16 H02K 11/00 H02K 29/00

Claims (3)

(57) [Claims] 1. A conductive support portion on a stator side, a non-conductive housing having a conductive bearing fixed to the support portion by a conductive fixing member, and a conductive rotor shaft supported by the bearing. And a conductive wire spring that is in contact with the bearing and one end of which is connected to the fixing member. 2. The capstan motor according to claim 1, wherein said wire spring is sandwiched between an end face of said bearing and a holding member of said bearing. 3. The coil spring according to claim 2, wherein the wire spring is press-fitted between the bearing and the holding member such that a coil portion is fitted on the rotor shaft, and one end of the coil portion is pressed against the fixed member. The described capstan motor.