JP2006330051A - Shutter unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable a shutter unit mounted on a digital single-lens reflex camera etc., to secure a magnetic attracting force which is strong enough not to make an armature fall from a yoke as a reaction when a mechanical inhibiting force of a driving lever is removed without altering the constitution of a conventional shutter unit. <P>SOLUTION: A projection part 9 is provided to make the center portion of the armature 5 thick, and a shoulder portion of the projection part 9 has a slope in a direction of adsorption by the armature 5 and two magnetic poles 1a and 1b of yoke 1. Consequently, magnetic flux flows to the projection part 9 to reduce magnetic saturation occurring to the center portion of the armature 5, and the area of confrontation between the magnetic poles 1a and 1b of the yoke 1 and the armature 5 in an adsorption direction increases to pass more magnetic flux, thereby the armature 5 obtains a larger adsorptive power. Here, the projection part 9 is provided in a vacant area of the armature 5 between the magnetic poles 1a and 1b of the yoke 1, so the constitution of the shutter unit is not altered. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a camera shutter device that drives a blade of a shutter by cutting off power to a coil.

  Conventional camera shutter devices using electromagnets are shown in FIGS. 6 is an exploded perspective view, FIG. 7 is an enlarged view of one of the two blade driving devices in FIG. 6, and FIG. 8 is an enlarged view of one of the two blade driving devices in FIG. FIG. A U-shaped yoke 1, a coil 2, a drive lever 3, a spring 4, and an armature 5 are attached to the front blade and the rear blade, respectively, and are driven independently. Here, the two magnetic poles of the yoke 1 are called a magnetic pole 1a on the side where the coil 2 of the yoke 1 is not wound, and a magnetic pole 1b on the side where the coil 2 of the yoke 1 is wound. The yoke 1 is attached to the shutter base plate with screws 7. The coil 2 is wound around the yoke 1 via a bobbin 8. Reference numeral 3 denotes a drive lever that can rotate around the spring 4. An armature 5 is attached to the tip of the lever portion by a mounting shaft 6, and a clockwise driving force is applied by the spring 4 as indicated by an arrow in FIG. 7. Yes. A shutter device configured in this way is described in Japanese Patent Laid-Open No. 7-128706.

The blade driving will be described below. The armature 5 is mechanically lifted up to the yoke 1 by the drive lever, and the coil 2 is energized to attract the armature 5 to the yoke 1, and then the mechanical deterrence is released and held only by the magnetic force. When the coil 2 is de-energized in this state, the armature 5 is separated from the yoke 1 by the spring force and rotates together with the drive lever 3 and the blades are driven in conjunction with this.
JP-A-7-128706

  However, in the above conventional example, when the mechanical deterrence is released, the armature 5 may be separated from the yoke 1 due to the reaction.

  In order to solve this problem, the attracting surface of the armature 5 has been smoothed so as to eliminate the magnetic gap in the contact portion as much as possible, thereby reducing the overall magnetic resistance and increasing the attracting force. However, this was not enough to solve this problem.

  In order to solve such a problem, an object of the present invention is to increase the attractive force between the magnetic poles 1a and 1b of the yoke 1 and the armature 5.

  In order to solve the above-mentioned problem, the first invention is a camera shutter device that drives the blades of the shutter by cutting off the power to the coil, and the central portion of the armature between the suction surface with the yoke is provided. The thickness is increased in the direction of adsorption with the yoke.

  According to this configuration, the magnetic saturation that occurs in the central portion of the armature of the magnetic circuit formed by the yoke and the armature is relaxed, and the magnetic permeability increases so that a large amount of magnetic flux passes through the yoke. Increases the adsorption power of amateurs.

  According to a second invention, in the first invention, a protrusion is provided on the upper surface of the central portion of the armature, and the shoulder of the protrusion is inclined with respect to the suction direction of the armature and the two magnetic poles of the yoke. It is characterized by this.

  According to this configuration, the attracting force between the magnetic pole of the yoke and the armature is increased by the same action as the first invention, and the opposing area in the attracting direction of the yoke and the armature is increased, so that the attracting force is further increased. Note that the configuration and size of the conventional shutter device are not changed by providing the protruding portion of the armature in the space between the magnetic poles of the yoke.

  According to a third aspect of the present invention, in the first aspect, the thickness of the armature is gradually increased from the both end portions of the armature to the central portion so as to protrude toward the magnetic pole side of the yoke, and a slope is formed. The two magnetic poles are also characterized by forming a slope in accordance with the armature.

  According to this configuration, the magnetic force of the yoke and the armature attracting force is increased by the same action as in the second invention, and the cross-sectional area of the magnetic path of the armature is larger than that in the configuration of the second invention. Magnetic saturation is more relaxed.

  According to a fourth invention, in the first invention, a protrusion is provided on the lower surface of the central portion of the armature.

  According to this configuration, the attraction force between the magnetic pole of the yoke and the armature is increased by the same action as in the first aspect of the invention. Since the projecting portion is provided in the space between the drive lever and the armature, the configuration and size of the conventional shutter device do not change. Further, since the protruding portion does not face the yoke, it is not necessary to process the slope, and the armature can be easily processed.

  As described above, by increasing the thickness of the central portion of the armature 5, the magnetic saturation that occurs in the central portion of the armature 5 can be alleviated, and the magnetic permeability increases so that a large amount of magnetic flux passes through the magnetic poles 1 a and 1 b of the yoke 1 and the armature 5. The adsorption power could be increased. Further, the attractive force between the magnetic poles 1a and 1b of the yoke 1 and the armature 5 can also be increased by increasing the facing area of the yoke 1 and the armature 5 in the attracting direction. These effects can be obtained without affecting the configuration and size of the shutter device. As described above, it is possible to prevent the armature 5 from dropping from the yoke 1 due to the reaction when the mechanical deterrence of the drive lever 3 is released.

(First embodiment)
FIG. 1 is a plan view showing a part of a camera shutter device according to a first embodiment of the present invention, and is a modification of the conventional example of FIG. .

  As shown in FIG. 1, this apparatus has a U-shaped yoke 1, a magnetic pole 1a on which the coil 2 of the yoke 1 is not wound, a magnetic pole 1b on which the coil 2 of the yoke 1 is wound, A coil 2, a drive lever 3 interlocked with a spring (not shown), an armature 5 integral with a mounting shaft 6 of the drive lever 3, a screw 7 for fixing the yoke 1 to a shutter device (not shown), and a bobbin 8 for winding the coil 2 Have. FIG. 1 shows a state where the coil 2 is energized and the yoke 1 is excited to attract the armature 5.

  In this embodiment, the armature 5 has a protruding portion 9 at the center so as to fit in the space between the magnetic poles 1a and 1b of the yoke 1, as shown in FIG. Further, the protruding portion 9 is an inclined surface (this portion is referred to as a shoulder portion) 9 a that is an attracting surface between the projecting portion 9 and the magnetic pole 1 a of the yoke 1, and an inclined surface 9 b that is an attracting surface between the projecting portion 9 and the magnetic pole 1 b of the yoke 1. Have As shown in FIG. 1, the magnetic poles 1 a and 1 b of the yoke 1 also have inclined surfaces 1 a ′ and 1 b ′ so that the attracting surface with the protruding portion 9 of the armature 5 matches the inclined surfaces 9 a and 9 b of the protruding portion 9. Here, the magnetic poles 1a and 1b of the yoke 1 represent suction surfaces including inclined surfaces 1a 'and 1b', respectively.

  The operation of the shutter device is the same as that of the conventional example, but the present invention is the same as that of the conventional example, except that the shape of the armature 5 and the magnetic poles 1a and 1b of the yoke 1 is changed. Is omitted.

  Next, FIGS. 2 and 3 show the simulation results of the magnetic flux when the coil 2 of the conventional shutter device and the shutter device of the present invention is energized, respectively. The calculation model includes a yoke 1, a coil 2, and an armature 5, and the yoke 1 has a simplified shape that does not affect the attractive force. Here, FIG. 2 and FIG. 3 perform calculation by unifying the calculation conditions and changing only the shape of the armature 5.

  In the present invention, the provision of the projecting portion 9 provides two features that a large amount of magnetic flux can be passed and that the area of the adsorbing portion can be increased. With these two features, the attractive force of the magnetic poles 1a and 1b of the yoke 1 and the armature 5 is increased.

  The first feature will be described in detail below.

  In the conventional shutter device as shown in FIG. 8, as shown in FIG. 2, when the coil 2 is energized, the magnetic flux concentrates at the center of the armature 5 and magnetic saturation occurs. From the simulation result of FIG. 2, it was found that the total magnetic flux flowing through the yoke was 2.24 [μWb]. On the other hand, in the first embodiment of the present invention as shown in FIG. 1, as shown in FIG. 3, the magnetic flux passes through the protruding portion 9, so that the magnetic saturation at the central portion of the armature 5 is alleviated. From the simulation result of FIG. 3, it was found that the total magnetic flux was 2.84 [μWb], and that the magnetic flux passed about 1.3 times as compared with the conventional shutter device. Therefore, in the present invention, by providing the protruding portion 9, magnetic flux passes through the protruding portion 9, magnetic saturation that occurs in the central portion of the armature 5 can be relaxed, and the magnetic permeability is increased so that more magnetic flux can be passed. Thus, the magnetic poles 1a and 1b of the yoke 1 and the armature 5 have an effect of increasing the attractive force.

  Next, the second feature will be described in detail.

  In the first embodiment of the present invention, as shown in FIG. 1, the opposing area in the attracting direction of the magnetic poles 1a, 1b of the yoke 1 and the armature 5 is increased as compared with FIG. As can be seen, magnetic flux passes through the protrusion 9. As a result, the area of the portions that are attracted to each other increases, and the saturation magnetic flux density does not change from the armature 5 of the conventional shutter device, so that the attracting force of the magnetic poles 1a, 1b of the yoke 1 and the armature 5 is increased.

  As described above, two features are obtained by the present invention, and the attractive force between the magnetic poles 1a and 1b of the yoke 1 and the armature 5 can be increased. 2 and 3, the suction force of the first embodiment of the present invention is 1.13 [N] while the suction force of the conventional shutter device is 0.87 [N]. It was confirmed that it increased 3 times. In addition, the increase in adsorption power was also confirmed in the actual machine.

  These two features can be obtained without affecting the configuration and size of the shutter device because the protrusion 9 is provided so as to fit in the space between the magnetic poles 1a and 1b of the yoke 1.

(Second embodiment)
FIG. 4 is a plan view showing a part of the shutter device for a camera according to the second embodiment of the present invention, which is a modification of the conventional example of FIG.

  This apparatus has the same configuration as that shown in FIG. 1 except that the thickness of the armature 5 is gradually increased from both ends of the armature 5 to the center so as to protrude toward the magnetic pole side of the yoke 1 to form a slope. The two magnetic poles of the yoke 1 also form slopes in accordance with the armature 5.

  Even with such a configuration, the same features as in the first embodiment can be obtained, and the attraction force between the magnetic poles 1a and 1b of the yoke 1 and the armature 5 is increased. Further, since the cross-sectional area of the magnetic path of the armature 5 is larger than that of the first embodiment, the magnetic saturation is further relaxed. In the first embodiment, the number of the upper surface that is the attracting surface with the magnetic pole of the yoke 1 of the armature 5 is two each, and there are two attracting surfaces with the magnetic poles 1 a and 1 b of the yoke 1. It has 5 surfaces in total with 1 surface of the central part. On the other hand, in this embodiment, there are two attracting surfaces 10a and 10b between the armature 5 and the magnetic pole of the yoke 1, and the armature 5 can be processed easily because the number of surfaces is smaller than that of the first embodiment. It has the feature of being.

(Third embodiment)
FIG. 5 is a plan view showing a part of the shutter device for a camera according to the third embodiment of the present invention, which is a modification of the conventional example of FIG.

  This apparatus has the same configuration as that shown in FIG. 1, except that a protrusion 11 is provided on the lower surface of the armature 5.

  Even with such a configuration, the same features as in the first embodiment can be obtained, and the attraction force between the magnetic poles 1a and 1b of the yoke 1 and the armature 5 is increased. Further, in the present embodiment, since only the protruding portion 11 is provided on the armature 5, an effect can be obtained without affecting the configuration and size of the shutter device. Further, since the protruding portion 11 does not face the yoke 1, it is not necessary to process the slope, and the armature 5 can be easily processed as compared with the configuration of the first embodiment.

The principal part top view which shows the 1st Example of this invention. The magnetic flux diagram of the conventional shutter device calculated | required by simulation. The magnetic flux diagram of the 1st Example of this invention calculated | required by simulation. The principal part top view which shows the 2nd Example of this invention. The principal part top view which shows the 3rd Example of this invention. The exploded perspective view of the conventional shutter device. FIG. B arrow view of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Yoke 1a Magnetic pole of the yoke 1 by which the coil 2 is not wound 1b Magnetic pole of the yoke 1 by which the coil 2 is wound 2 Coil 3 Drive lever 4 Spring 5 Armature 6 Mounting shaft 7 Screw 8 Bobbin 9 Protruding part ( (Amateur top)
9a Slope of the projection 9 on the side where the coil 2 is not wound 9b Slope of the projection 9 on the side where the coil 2 is wound 10a Slope of the armature 5 on the side where the coil 2 is not wound 10b Coil 2 is wound The slope of the armature 5 on the side that is on

Claims (4)

  In the camera shutter device that drives the blades of the shutter by turning off the power to the coil, the central portion of the armature between the suction surface with the U-shaped yoke is thickened in the suction direction with the yoke. Shutter device.   2. The shutter according to claim 1, wherein a protrusion is provided on an upper surface of a central portion of the armature, and a shoulder portion of the protrusion is inclined with respect to a suction direction of the armature and the two magnetic poles of the yoke. apparatus.   2. The slope according to claim 1, wherein the thickness of the armature is gradually increased from both ends of the armature to the center so as to protrude toward the magnetic pole side of the yoke, and the two magnetic poles of the yoke also form the armature. A shutter device characterized in that a slope is formed in accordance with the above.   The shutter device according to claim 1, wherein a protrusion is provided on a lower surface of a central portion of the armature.

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