JP3215960B2 - Ring clutch for camera power transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, an autofocus mechanism and zoom mechanism provided in a lens barrel of a camera.
The present invention relates to a ring clutch provided in an interlocking system such as a lens mechanism.

[0002]

2. Description of the Related Art An auto-focus mechanism and a zoom lens mechanism provided in a lens barrel of a camera are a motor which is a driving source.
In many cases, the interlocking drive system is intermittently driven by a clutch. This type of clutch is incorporated in a lens barrel.

[0003]

The problem with the clutch incorporated in the lens barrel as described above is that a clutch having a sufficient clutch structure that can be accommodated in the cylindrical shape of the lens barrel without obstructing the photographing optical path has been developed. That is not. For this reason, since the clutch is incorporated in the narrow space of the lens barrel, it is difficult to house a clutch having a sufficient clutch structure for transmitting the driving force.

For this reason, the lens barrel is entirely or partially enlarged to provide a storage space, and a clutch is incorporated into this space. It should be noted that a clutch having a small structure can be accommodated, but it is not practically preferable because transmission of driving force is unreasonable.

In view of the above circumstances, the present invention has a thin structure and sufficient mechanical strength, and can be housed in a cylindrical body such as a lens barrel of a camera in accordance with the cylindrical shape. mosquitoes that can be
The purpose is to develop a ring clutch for power transmission of Mera .

[0006]

In order to achieve the above-mentioned object, according to the present invention, a magnetic material having a small concave section with an open outer peripheral side is formed in a circular ring having a large internal space, and is formed in the direction of the ring center line. A first connecting means comprising a yoke whose width is sufficiently smaller than the diameter of the ring, and a magnet integrally projecting from the concave bottom of the yoke along the ring; A second connecting means which is arranged in the yoke recess so as to have a smaller width than the yoke width of the connecting means, and which is formed as a circular ring concentric with the first connecting means; The first and second connecting means are formed of a hollow frame-shaped yoke made of a magnetic material having a window hole of a predetermined width formed along the peripheral surface, and an exciting coil housed in the yoke. The first and second connecting means are connected to the center line of the ring by the power supply of the exciting coil. Magnetically into contact with the click concave wall portion, - the second coupling means are relatively moved Yo of the first coupling means
A ring type clutch for power transmission of a camera, characterized in that one of the connecting means is configured to apply a rotational force about the center of rotation to the ring center and output the rotation from the other connecting means.

[0007]

Normally, when the excitation coil is not powered, the yoke of the first connecting means is magnetized by the yoke of the first connecting means because the yoke of the first connecting means is magnetized by the magnetic action of the magnet. It is sucked and is magnetically in contact with one of the concave walls of the yoke concave portion and is stationary.

When the exciting coil is supplied with a forward current for a short time, the yoke of the second connecting means is magnetized.
Magnetic poles of different magnetism are generated at the edges of the holes on both sides where the window holes are formed. At this time, when the magnetic pole of the magnet and the magnetic pole at the edge of the hole approaching the magnet become different in magnetism, the first and second connecting means do not move, and when they become the same magnetic pole. The first and second connecting means relatively move by magnetic repulsion.

That is, if the first connecting means is fixed, the yoke of the second connecting means moves in the direction of the ring center line,
When the connecting means is fixed, the yoke of the first connecting means moves in the ring center line direction. In the first connecting means or the second connecting means moved in this way, the yoke of the second connecting means abuts on the other wall of the concave portion of the yoke of the first connecting means, and in this state, the yoke of the yoke of the first connecting means becomes magnetic. Is held.

If the exciting coil is supplied with the reverse current for a short time while the first connecting means or the second connecting means is moved as described above, the first and second connecting means are relatively moved in the opposite direction. And the yoke of the second connecting means abuts against one wall of the concave portion of the yoke of the first connecting means, and this state is magnetically maintained.

In this manner, after the first connecting means or the second connecting means has moved in one direction and the other direction, the moving position is maintained, so that the connection between the yoke of the connecting means and the load body. 2
A stable ring-type clutch mechanism can be configured.
For example, the yoke of the connecting means is moved in one direction to be connected to the load, and is moved in the other direction to separate the yoke from the load. The power from the driving source is the first and second
The power is applied to one of the connecting means, and power is transmitted to the camera load from the other connecting means.

[0012]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a partially cutaway perspective view of a ring-type clutch.
Reference numeral 2 denotes a stator configured as a second connecting means.

The mover 11 includes a yoke 13 and a magnet 1
4 and a mover having three magnetic poles. The yoke 13 is formed by forming a magnetic material having a U-shaped (concave) cross section into a circular ring, and the center point 0 through which the center line 15 passes is the center of the circle.

The magnet 14 has an annular shape with a quadrangular cross section, and is integrally provided along the ring on the concave bottom 13c of the yoke 13. The magnet 14 is magnetized such that the inner peripheral side on the concave bottom 13c side is the S pole and the outer peripheral side is the N pole.

The stator 12 includes a yoke 16, an exciting coil 1
7, and a spacer 18. The yoke 16 is a hollow frame made of a magnetic material formed in a circular ring with the center point 0 as a circular center. A window hole 19 having a predetermined width is formed on the inner peripheral surface of the yoke 16 along the ring. It is.

The width of the yoke 16 is determined by the concave width of the yoke 13 of the mover 11 (flange portions 13a, 1a, 1b).
3b), and the movable element 11 is
It moves in accordance with the concave width of the hook 13.

An exciting coil 17 is provided in a hollow frame forming the yoke 16. The exciting coil 17 is wound along a ring, and the yoke 16 is magnetized by the power supply of the coil 17 to form a hole edge 19 a on one side of the window hole 19.
And magnetic poles of different magnetism are generated at the hole edge 19b on the other side.

Spacers 18 are fixed to both outer surfaces of the yoke 16, and the holding force of the yoke 16 at the moving position is adjusted by the spacers 18. That is, the above-mentioned holding force is adjusted so that the thickness of the spacer 18 is determined in relation to the moving force of the yoke 16 which is determined by the value of the power supply current of the exciting coil 17.

The operation of the above-mentioned ring type clutch is shown in FIGS.
This will be described with reference to a partially enlarged view shown in FIG. FIG. 2 shows that the flange portion 13a of the yoke 13 (first connecting means) is in contact with the stator 12 and stable when the excitation coil 17 is not supplied with power.

That is, the flange portion 13 of the yoke 13
Since the magnets a and 13b are magnetized to the S pole according to the polarity of the magnet 14, the yoke 16 is attracted and stably held by the magnetization of the flange portion 13a. FIG. 5 (A)
Is a longitudinal sectional view showing this operation example for the entire clutch.

FIGS. 3 and 4 show an operation state when the exciting coil 17 is supplied with the forward current I for a short time in the stable state of FIG. In the initial stage of power feeding, as shown in FIG.
The two yoke 16 are magnetized, and an S pole is generated at the hole edge 19a of the window hole 19, and an N pole is generated at the hole edge 19b. The exciting coil 17 is wound so that a forward current I flows to generate a magnetic flux φ indicated by a dashed line in the figure.

For this reason, the N pole of the magnet 14 is repelled by the N pole of the hole edge 19b, and the S pole of the flange 13a is repelled.
The pole is repelled by the S pole of the hole edge 13a, and at the same time, the N pole of the magnet 14 is attracted to the S pole of the hole edge 19a, and the mover 11 moves leftward in the drawing. When the mover 11 moves in this manner, as shown in FIG.
Flange portion 13b abuts on the stator 12.

At this point, the magnetic flux .phi.
6. Since it passes through the magnet 14, the mover 11
After the power supply to the exciting coil 17 is stopped, the movable element 11 is moved to the stator 12 by the electromagnetic force of the S pole generated in the flange portion 13b of the yoke 13.
Is stably maintained. FIG. 5B is a longitudinal sectional view showing this moving operation for the entire clutch.

When the exciting coil 17 is supplied with a reverse current in a state where the mover 11 is at the moving position shown in FIG. 4, magnetic poles having opposite polarities to the illustrated ones are formed on the hole edges 19a and 19b of the stator 12. As a result, the mover 11 moves rightward in the drawing in the same manner as described above, and is stably held at the movement position shown in FIG. As described above, the clutch of this embodiment is a bistable ring-type clutch that is stably held at the position where the mover 11 has moved in one direction and the position where it has moved in multiple directions.

FIG. 6 is a partial sectional view showing an example in which the above-mentioned ring-type clutch is mounted on a lens barrel of a camera. In this figure, 21 is a fixed frame, 22 is a first moving frame meshed with the fixed frame 21 by helicoid screws, 23 is a front group lens supported by the first moving frame 22, 2.
Reference numeral 4 denotes a second moving frame that moves within the first moving frame 22, and reference numeral 25 denotes a rear lens group supported by the second moving frame 24.

Reference numeral 26 denotes a cylindrical gear to which the stator 12 of the clutch is integrally attached, which is provided with a long gear 26a in the optical axis direction. It is fitted rotatably. The cylindrical gear 26 is rotated around the optical axis by an interlocking gear 28 driven by the output of a motor 27. The motor 27 is installed on the fixed frame 21.

[0027] 29 is the second moving frame by Herikoi de screws 2
The interlocking cylinder 4 is rotatably fitted to the first moving frame 22, and the movable element 11 of the clutch moves around the outer circumference of the interlocking cylinder 29.
Reference numerals 30a to 30d denote connecting members provided on the mover 11, the first moving frame 22, and the interlocking cylinder 29. This connecting member is formed of, for example, engaging teeth, and when the movable element 11 moves to the left, the connecting members 30a and 30c mesh with each other,
When the mover 11 moves to the right, the connecting member 3
0b, 30 d engage, to reliably transmit the rotation of the movable member 11 to the first moving frame 22 or interlocking cylinder 29.

The lens barrel having the ring-shaped clutch as described above has a structure in which the movable member 11 of the clutch is moved to the left and connected to the first moving frame 22 as shown in FIG.
The front group lens 23 and the rear group lens 2 are driven by driving the motor 27.
5 are both moved in the optical axis direction.

That is, in this case, the rotation of the motor 27 causes the cylindrical gear 26 to rotate, and the stator 12 to rotate around the optical axis. Therefore, the mover 11 rotates in the same direction and drives and rotates the first moving frame 22.

When the first moving frame 22 is interlocked and rotated, it moves in the optical axis direction according to the helicoid screw, and the second moving frame 24 is interlocked by the first moving frame 22 via the interlocking cylinder 29 to move in the optical axis direction. Go to

When the ring type clutch is switched and the mover 11 is moved rightward to connect the interlocking cylinder 29, the motor 2
Only the rear lens group 25 moves in the direction of the optical axis in accordance with the rotational driving of the lens.

That is, in this case, since the mover 11 of the clutch moves away from the first moving frame 22 and is connected to the interlocking cylinder 29, the rotation of the mover 11 is transmitted to the interlocking cylinder 29. It rotates by receiving the rotational driving force of the motor 27,
Thus, only the second moving frame 24 moves in the optical axis direction according to the helicoid screw.

By switching the ring type clutch in this way, the front lens group 23 and the rear lens group 25 are moved together, and by moving only the rear lens group 25, zooming and focusing are achieved. Can be performed.

The embodiment of the present invention has been described above. However, it is also possible to fix the mover 11 and move the stator 12.

[0035]

As described above, in the ring-type clutch according to the present invention, the first and second connecting means are formed as concentric small-width rings, and one of the first and second connecting means is formed by electromagnetic force. Since it is configured to move in the direction of the center line of the circle to intermittently connect with the load body, a mechanically strong thin type clutch structure and a ring type clutch having a wide internal space are obtained. As a result, it is embedded in narrow spaces such as camera lens barrels.
This is extremely advantageous as a power transmission ring clutch.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view of a ring-type clutch showing one embodiment of the present invention.

FIG. 2 is a partially enlarged cross-sectional view of the clutch, illustrating an operation when power is not supplied to an excitation coil.

FIG. 3 is a sectional view similar to FIG. 2, showing an initial operation when power is supplied to an exciting coil;

FIG. 4 is a sectional view similar to FIG. 2, showing an operation in which a mover has moved.

FIG. 5A is a longitudinal sectional view of the clutch showing an operation when power is not supplied to an exciting coil. FIG.
(B) is a longitudinal sectional view of the clutch, showing an operation in which the mover has moved.

FIG. 6 is a partial sectional view showing a lens barrel of a camera on which the above-described clutch is mounted.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Mover 12 Stator 13 Yoke 14 Magnet 16 Yoke 17 Exciting coil 18 Spacer 19 Window hole 21 Fixed frame 22 First moving frame 23 Front group lens 24 Second moving frame 25 Rear group lens 26 Cylindrical Gear 27 Motor 28 Interlocking gear 29 Interlocking cylinder

Claims (1)

(57) [Claims] 1. A yaw in which a magnetic material having a small width and a concave cross section whose outer peripheral side is opened is formed in a circular ring having a large internal space, and the width in the ring center line direction is sufficiently smaller than the ring diameter.
First connecting means comprising a magnet and a magnet integrally projecting from the concave bottom of the yoke along the ring, and the yoke having a width smaller than the yoke width of the first connecting means. A first connecting means and a second connecting means formed as a circular ring concentric with the first connecting means, wherein the second connecting means has a window having a predetermined width formed along the inner peripheral surface of the ring. The first and second connecting means are formed into a thin ring shape by a hollow frame-shaped yoke made of a material and an exciting coil housed in the yoke. The second connecting means is relatively moved in the direction of the center line of the ring to magnetically contact the second connecting means with the yoke concave wall portion of the first connecting means, and is rotated by one of the connecting means. It is characterized in that a rotational force with the center at the center of the ring is applied and the other connecting means rotates and outputs. Camera power transmission ring-shaped clutch to be.