JP2594422Y2 - Spring clutch - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spring clutch in which a coil spring is fitted over each cylindrical portion of first and second hubs arranged on the same axis.

[0002]

2. Description of the Related Art A conventional spring clutch is disclosed in
A countermeasure against abrasion powder as proposed in Japanese Patent Application Laid-Open No. 3-187729 is taken.

A spring clutch incorporated in a paper feed mechanism or the like of a copier includes a hollow shaft-shaped first hub having a first cylindrical portion in which a coil spring is wound around a substantially central portion in an axial direction, and a first hub having a hollow shaft. A second hub having a cylindrical portion having substantially the same size as the first cylindrical portion, the second hub being rotatably fitted to a second cylindrical portion having a smaller diameter than the first cylindrical portion of the first hub; Power is transmitted by winding a coil spring around the first cylindrical portion of the hub and the cylindrical portion of the second hub.

In this spring clutch,
A third hub which is on the opposite side of the first hub from the second cylindrical portion in the axial direction.
A field core having an electromagnetic coil installed in a cylindrical portion via an iron-based oilless metal is supported.

A magnetic plate is fitted into the opening of the field core, and a cylindrical armature is inserted from the center hole of the magnetic plate toward the iron-based oilless metal. The magnetic flux of the electromagnetic coil forms a magnetic circuit flowing through the field core, the magnetic plate / armature, and the iron-based oilless metal.

Therefore, since one of the hooks of the coil spring is hooked on the armature and the other hook is hooked on the second hub, the armature is magnetically attracted to the iron-based oilless metal as a fixing member, When one hook of the coil spring is braked, the rotation of the second hub causes the coil spring to move to the first hub of the first hub.
Wound around the cylindrical portion and the cylindrical portion of the second hub.

In the spring clutch having such a configuration and operation, power is transmitted while the armature is in frictional sliding contact with the iron-based oil-less metal. .

On the other hand, in the same publication, a wear powder reservoir is provided in a field core, and wear powder generated when an armature is adsorbed on an iron-based oil-less metal is deposited on the wear powder reservoir and processed. It is described that wear powder does not adhere to the operating part and hinder the operation of the operating part.

[0009]

However, in the conventional spring clutch, an annular groove is formed on an inner peripheral surface of a cylindrical portion of a coil bobbin around which an electromagnetic coil is wound or a side surface of an iron-based oil-less metal as a wear powder reservoir in a field core. However, in order to obtain a sufficient volume of the abrasion powder reservoir by providing an annular groove on the same axis as the coil bobbin, the thickness of the cylindrical portion must be increased.

The side surface of the iron-based oilless metal is a surface on which the end of the armature is adsorbed, and the air gap between the iron-based oilless metal and the armature is increased, so that the side surface in the magnetic circuit of the electromagnetic coil is reduced. The magnetic resistance increases.

Therefore, there have been problems such as a large design change or an increase in the outer diameter of the spring clutch in order to adopt it in an existing spring clutch. The purpose of the present invention is to eliminate a problem caused by wear powder by a wear powder reservoir that can be easily implemented.

[0012]

In order to achieve such an object, the present invention employs first and second coaxially arranged first and second axes .
In a spring clutch in which a coil spring is fitted over each cylindrical portion of the second hub, at least one of the outer peripheral surfaces of the cylindrical portion has a circular shape at an angle different from the pitch angle of the coil spring. Extending in the circumferential direction
Characterized in that a curve shaped groove which is continuous or intermittent consisting groove.

[0013]

The power is transmitted to the spring clutch by winding a coil spring around each cylindrical portion of the first and second hubs. Wear powder generated by repeating the operation is deposited in the grooves formed in the cylindrical portion of the hub.

[0014]

1 to 4 show a spring clutch according to an embodiment of the present invention. FIG. 1 is a side view showing a cross section of an upper half, FIG. 2 is an enlarged view of a main part of FIG. 1, and FIG. FIG. 4 is a side view of the coil spring of FIG. Hereinafter, embodiments will be described with reference to these drawings.

This spring clutch is an electromagnetic spring clutch most suitable for use in a paper feed mechanism of a copying machine, a printer, or the like, and is mounted on the rotating shaft 1. Rotary axis 1
The first hub 2 in the form of a hollow shaft having a shaft hole into which
A first cylindrical portion 2a having a large diameter is formed substantially at the center in the axial direction, and second and third cylindrical portions 2b and 2 are provided on both sides of the first cylindrical portion 2a.
c is formed.

The first hub 2 is made of a resin material, and a first hub 2 around which a coil spring 6 to be described later is wound.
A ring 3 made of a metal material is embedded in the cylindrical portion 2a.
On the other hand, a second hub 4 made of a resin material is rotatably fitted to the second cylindrical portion 2 b of the first hub 2 and is prevented from falling off by a snap ring 5. The second hub 4 has the first hub
A cylindrical portion 4a having an outer diameter substantially the same as the first cylindrical portion 2a (specifically, the outer diameter of the ring 3) of the hub 2 and a tooth portion 4b meshing with a gear (not shown) are formed.

The first cylindrical portion 2a of the first hub 2
A coil spring 6 is fitted and mounted over the outer peripheral surface of the (ring 3) and the outer peripheral surface of the cylindrical portion 4a of the second hub 4. One hook 6 a of the coil spring 6 is hooked on the second hub 4, and the other hook 6 b is hooked on the armature 7.

The armature 7 is an annular member having an L-shaped cross section, and its cylindrical portion 7a is inserted between the outer peripheral surface of the coil spring 6 and the inner peripheral surface of a coil bobbin 13 described later. The disk 7 of the armature 7
b faces a side surface of the field core 8 described later with a predetermined air gap in the axial direction.

Reference numeral 8 denotes a third cylindrical portion 2c of the first hub 2.
A field core is supported via a bearing 9 made of an iron-based oilless metal, and is prevented from coming off by a thrust washer 10 and a snap ring 11 made of a resin material.

The field core 8 is formed by bending a rectangular plate material into a shape having a substantially U-shaped cross section, and has a bottom portion 8a having a central hole into which the cylindrical portion of the bearing 9 is press-fitted and fixed.
A pair of flat plate portions 8b extending axially from upper and lower ends (on the drawing) of the bottom portion 8a, and a pair of inner flange portions 8c extending radially inward from respective distal ends of the flat plate portions 8b. It is a shape having.

The field core 8 is provided with a coil bobbin 13 in which an electromagnetic coil 12 partially surrounded by a space defined by the bottom 8a, the flat plate 8b, and the inner flange 8c is wound. The coil bobbin 13 has a disc-shaped inner flange portion 13 a formed between the disc portion of the bearing 9 and the bottom portion 8 a of the field core 8.

The coil bobbin 13 is formed with a projection (not shown) in the axial direction, and the projection is engaged with a notch (not shown) formed on the bottom 8a of the field core 8. As a result, the coil bobbin 13 is prevented from rotating. The field core 8 is prevented from rotating by fixing a rotation preventing plate 8d cut and raised radially outward to a fixed housing (not shown).

On the other hand, a ring-shaped rotor 14 is fitted and fixed to a disk portion 2d formed between the first cylindrical portion 2a and the third cylindrical portion 2c of the first hub 2. Rotor 1
4 only needs to be fitted to the first hub 2 so as to be integrally rotatable, and may not be integrally fixed.

The magnetic flux generated when the electromagnetic coil 12 is energized is applied to the inner flange 8 c of the field core 8.
From the disk portion 7b of the armature 7, flows from the cylindrical portion 7a of the armature 7 to the rotor 14, and forms a magnetic circuit flowing from the bearing 9 to the field core 8.

Next, a description will be given of the wear powder reservoir, which is the gist of the present invention. On the outer peripheral surface of the ring 3 embedded (insert-molded) in the first hub 2, for example, a groove having a continuous curve of a pitch angle α, a so-called spiral groove 3a is formed. 1, the direction of rotation of the rotary shaft 1 as viewed from the right side of FIG. 1 is indicated by reference numeral A. Similarly, the spiral groove when viewed from the right side of the ring 3 shown in FIGS. 3a is
They are formed in the same direction as shown by the reference numeral B.

FIG. 4 shows a side view of the coil spring 6. When the coil spring 6 is wound from the right side, the direction of rotation of the rotating shaft 1 and the spiral of the ring 3 are indicated by reference numeral C. This is the same direction as the winding direction of the groove 3a.

The spring clutch having the above-described structure is configured such that the rotating shaft 1 and the first hub 2,
The rotor 1 fitted to the first hub 2 so as to be integrally rotatable.
4 is rotating. When the electromagnetic coil 12 is energized, the armature 7 is magnetically attracted to the rotor 14, so that one hook 6b of the coil spring 6 is moved in the winding direction of the coil spring 6, and the coil spring 6
Around the ring 3 of the hub 2 and the cylindrical portion 4a of the second hub 4. Therefore, power is transmitted from the rotating shaft 1 to the second hub 4. If the power supply to the electromagnetic coil 12 is cut off,
Power transmission is shut off.

When such an operation is repeated, abrasion powder is generated from the frictional engagement surface between the armature 7 and the rotor 14, but the spiral of the ring 3 having the same winding direction as the rotating direction of the rotating shaft 1 is formed. Part of the wear powder is deposited in the groove 3a.

A part of the abrasion powder is scattered by the centrifugal force on the inner peripheral surface of the cylindrical portion of the coil bobbin 13. Such scattered abrasion powder is formed on the inner peripheral surface of the existing cylindrical portion of the coil bobbin 13. A shallow groove 1 having a linear shape, a curved shape, or a combination thereof that is open at one end to the outside.
5 may be deposited.

Further, in the spring clutch of the embodiment described above, wear powder is deposited in an air gap formed between the end face of the cylindrical portion 7a of the armature 7 and the side surface of the rotor 14, so that the armature 7 The original purpose is to prevent the operation of the
With the spiral groove 3a of the ring 3 as the winding direction B in the same direction as the rotation direction A of the rotating shaft 1, a screw effect of moving wear powder deposited in the air gap is expected.

However, in the present invention, any structure may be used as long as the volume of the abrasion powder reservoir is sufficient, and the shape of the spiral groove 3a serving as the abrasion powder reservoir is a curve having the same angle as the pitch angle β of the coil spring 6. It is not good.

That is, if the groove 3a has the same or similar angle as the pitch angle β of the coil spring 6, a galling phenomenon occurs when the coil spring 6 is wound around the ring 3, and the operating characteristics (connection time) This is because a large variation is seen in

Therefore, the pitch angle α of the spiral groove 3a of the ring 3 is made sufficiently larger than the pitch angle β of the coil spring 6, or the pitch angle α of the spiral groove 3a of the ring 3 as shown in FIG. It is preferable to configure a coil spring 16 having a pitch angle that opens in the opposite direction and a winding direction D in the same direction as the coil spring 6.

Further, in the spring clutch of the embodiment, the first hub 2 made of a resin material in which the ring 3 is embedded is provided.
However, the ring 3 is formed as a winding formed at a predetermined pitch angle similar to that of the coil spring, and the ring made of this winding is fitted and fixed to the first hub 2 to thereby reduce the volume of the wear powder reservoir. Can be increased. Further, the entire first hub 2 may be made of a metal material or a resin material, and a wear powder reservoir may be formed on the outer peripheral surface of the first cylindrical portion 2a.

[0035]

As described in detail above, in the spring clutch of the present invention, the spring clutch in which the coil spring is fitted over the cylindrical portions of the first and second hubs arranged on the same axis. In at least one of the outer peripheral surfaces of the cylindrical portion, in the circumferential direction at an angle different from the pitch angle of the coil spring
It is provided with the continuous or intermittent grooves curvilinear groove extending, easily carried wear debris measures existing spring clutch.

Since the groove serving as the abrasion powder reservoir is formed at an angle different from the pitch angle of the coil spring, the quality of the spring clutch can be reduced without affecting the operating characteristics of the spring clutch. Can be provided.

[Brief description of the drawings]

FIG. 1 is a cross-sectional side view of an upper half of a spring clutch according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a main part of the spring clutch of FIG. 1;

FIG. 3 is a side view of the ring of FIG. 1;

FIG. 4 is a side view of the coil spring of FIG. 1;

FIG. 5 is a side view of another coil spring that can be incorporated in the spring clutch of FIG. 1;

[Explanation of symbols]

 2 First hub 3 Ring 4 Second hub 6 Coil spring 7 Armature 8 Field core 12 Electromagnetic coil

Claims (1)

(57) [Scope of request for utility model registration] 1. A spring clutch in which a coil spring is fitted over respective cylindrical portions of first and second hubs arranged on the same axis, at least one of an outer peripheral surface of the cylindrical portion. On the outer peripheral surface, a curved shape extending in the circumferential direction at an angle different from the pitch angle of the coil spring
A spring clutch having a continuous or intermittent groove composed of the following grooves .