Source: https://patents.google.com/patent/JP4401696B2/en
Timestamp: 2020-07-07 09:47:12
Document Index: 65032098

Matched Legal Cases: ['art 203', 'arts 4', 'art 5', 'arts 4', 'art.\n13', 'arts 4', 'arts 4', 'art 4', 'art 4', 'arts 4']

JP4401696B2 - Driving device, light amount adjusting device, and lens driving device - Google Patents
Driving device, light amount adjusting device, and lens driving device Download PDF
JP4401696B2
JP4401696B2 JP2003186277A JP2003186277A JP4401696B2 JP 4401696 B2 JP4401696 B2 JP 4401696B2 JP 2003186277 A JP2003186277 A JP 2003186277A JP 2003186277 A JP2003186277 A JP 2003186277A JP 4401696 B2 JP4401696 B2 JP 4401696B2
outer magnetic
JP2003186277A
JP2004129485A (en
香織 堀池
2002-07-29 Priority to JP2002219361 priority Critical
2003-06-30 Application filed by キヤノン株式会社 filed Critical キヤノン株式会社
2003-06-30 Priority to JP2003186277A priority patent/JP4401696B2/en
2004-04-22 Publication of JP2004129485A publication Critical patent/JP2004129485A/en
2010-01-20 Publication of JP4401696B2 publication Critical patent/JP4401696B2/en
The present invention relates to an improvement of a driving device suitable for a shutter device or the like in an imaging device such as a digital camera, a light amount adjusting device, and a lens driving device suitable for driving a lens of the imaging device.
A conventional shutter device for a lens shutter camera is shown in FIG. 17 (see, for example, Patent Document 1).
In the figure, 101 is a magnet that is a permanent magnet, 102 is a drive lever, and 102 a is a drive pin provided on the drive lever 102. The drive lever 102 is fixed to the magnet 101 and rotates integrally with the magnet 101. Reference numeral 103 denotes a coil, and reference numerals 104 and 105 denote a stator made of a soft magnetic material and excited by the coil 103. The stator 104 and the stator 105 are joined at the 104a portion and the 105a portion, and are integrated on the magnetic circuit. By energizing the coil 103, the stator 104 and the stator 105 are excited, and the magnet 101 is rotationally driven within a predetermined angle. 106 and 107 are shutter blades, and 108 is a ground plane. The shutter blades 106 and 107 are rotatably attached to the pins 108b and 108c of the base plate 108 at the holes 106a and 107a, and the long holes 106b and 107b are slidably fitted to the drive pin 102a. , The shutter blades 106 and 107 are rotationally driven around the holes 106a and 107a, and open and close the opening 108a of the main plate. In order to prevent an increase in cost, there is a type in which the magnet is formed of a plastic magnet and the drive pin is integrally formed.
Reference numeral 109 denotes a front base plate that holds the shutter blades 106 and 107 so as to be movable with respect to the base plate 108, and 110 denotes a rear base plate that holds the stators 104 and 105 and holds the magnet 101 rotatably.
By the way, a digital camera that uses a CCD or the like as an image sensor and photoelectrically converts an object scene image and records it as information on a still image on a storage medium has become popular. An example of an operation related to exposure of this type of digital camera will be briefly described below.
First, the main power is turned on prior to photographing, and when the image sensor is in an operating state, the shutter blades are held in an open position where the image sensor can be exposed. As a result, charge accumulation and discharge transfer are repeated in the imaging device, and the object scene can be observed by the image monitor.
After that, when the release button is pressed, the aperture value and the exposure time are determined according to the output of the image sensor at that time, and when it is necessary to reduce the aperture diameter, Is driven and set to a predetermined aperture value. Next, the image sensor that has released the accumulated charge is instructed to start accumulating charges, and at the same time, the exposure time control circuit is activated using the accumulation start signal as a trigger signal. The shutter blade is driven to a closed position that blocks exposure to the image sensor. After exposure to the image sensor is interrupted, the accumulated charge is transferred, and image information is recorded on the recording medium via the image writing device. The reason why the image sensor is prevented from being exposed during the transfer of the charge is to prevent the charge from being changed by extra light during the transfer of the charge.
In addition to the shutter device as described above, there are those having a mechanism for advancing and retracting the ND filter and those having a mechanism for advancing and retracting an aperture restricting member having a small aperture diameter.
Although the thickness of the shutter device can be reduced, the coil and the stator occupy a large range on the main plate. In view of this point, a light amount adjusting device shown in FIG. 18 has been proposed (see, for example, Patent Document 2).
In the figure, 201 is a cylindrical rotor, 201a is magnetized to N pole and 201b is magnetized to S pole. Reference numeral 201 c denotes an arm formed integrally with the rotor 201, and a drive pin 201 d extends from the arm 201 c in the rotation axis direction of the rotor 201. A coil 202 is arranged in the axial direction of the rotor 201. Reference numeral 203 denotes a stator made of a soft magnetic material and excited by the coil 202. The stator 203 has an outer magnetic pole portion 203 a that faces the outer peripheral surface of the rotor 201, and an inner cylinder that is inserted into the rotor 201. An auxiliary stator 204 is fixed to the inner cylinder of the stator 203 and faces the inner peripheral surface of the rotor 201. By energizing the coil 202, the outer magnetic pole part 203a and the auxiliary stator 204 are excited, and the rotor 201 rotates to a predetermined position. 207 and 208 are shutter blades, and 205 is a ground plane. The shutter blades 207 and 208 are rotatably attached to the pins 205b and 205c of the base plate 205 at the holes 207a and 208a, and the long holes 207b and 208b are slidably fitted to the drive pins 201d. Reference numeral 206 denotes a torsion spring that applies an elastic force to the rotor 201 so as to press the drive pin 201d against the ends of the long holes 207b and 208b. By energizing the coil 202 and rotating the drive pin 201d together with the rotor 201 against the elastic force of the torsion spring 206, the shutter blades 207 and 208 are rotationally driven around the holes 207a and 208a, and the opening of the ground plate 205a Open / close drive.
By setting it as the light quantity adjustment apparatus of such a structure, a compact light quantity control apparatus can be comprised.
Japanese Patent Laid-Open No. 10-010604
JP 2002-49076 A
The light quantity adjusting device shown in FIG. 18 has a shape more suitable for miniaturization than that shown in FIG. 17, but the shutter blades 207 and 208 can be opened or closed simply by switching on and off the power supply to the coil. It can only be held in either position. In other words, the light quantity adjustment blade is driven only in two states, that is, the light quantity adjustment blade is driven either to cover the opening or to be retracted. For example, an intermediate opening state is also set. A possible simple device is desired.
An object of the present invention is to provide a simple driving device, light amount adjusting device, and lens driving device having three stop positions.
In order to achieve the above object, the present invention has a cylindrical magnet portion whose outer peripheral surface is divided in the circumferential direction and is magnetized on different poles, and a rotor rotatable around an axis, and an axially extending portion. At least one outer magnetic pole portion that is formed by extending and facing the outer peripheral surface of the magnet portion, an inner magnetic pole portion that is at a position facing the outer magnetic pole portion and that faces the inner peripheral surface of the magnet portion, A drive device having an axially arranged coil for exciting the outer magnetic pole part and the inner magnetic pole part, wherein the operating range of the rotor is The range in which the cogging force acting on the magnet portion of the rotor is in the opposite direction by switching the energization direction to the coil A center of the magnetized pole of the magnet part and the outer magnetic pole part The center of Is set to a range that does not include the opposing region, and the center angle per pole of the outer magnetic pole part is set within the operating range of the rotor, and the center of the magnetized pole of the magnet part and the outer magnetic pole part The center of Is set to an angle that does not oppose, and the ratio of the center angle per pole of the outer magnetic pole part to the center angle per pole of the magnet part magnetized is Y, and the ratio of the magnet part to the radial thickness of the magnet part When the value of the ratio of the length on the circumference per magnetized pole is X, the drive device satisfies the condition of −0.3X + 0.72 <Y.
Further, the light amount adjusting member is configured to control the light amount adjusting member to three stop positions by using the driving device having the same configuration as described above, and to change the light amount passing through the opening. Further, the lens driving device is configured to change the focal length by controlling the lens to three stop positions using a driving device having the same configuration as described above.
1 to 8 are views showing a light amount adjusting device according to a first embodiment of the present invention. FIG. 1 is an exploded perspective view of the light amount adjusting device, and FIG. 2 is a sectional view thereof. Among the cross-sectional views of the driving apparatus of FIG. 2, the left half is a cross-sectional view at a portion where the outer magnetic pole portion of the stator is present, and the right half is a cross-sectional view at a portion where the outer magnetic pole portion is not present. 3 is a BB cross-sectional view of FIG. 2 when the rotor is in the third position, FIG. 4 is a BB cross-sectional view of FIG. 2 when the rotor is in the first position, and FIG. FIG. 3 is a cross-sectional view taken along the line BB in FIG. FIG. 6 is a diagram showing the rotational position of the light quantity adjusting blade when the rotor is in the third position, FIG. 7 is a diagram showing the rotational position of the light quantity adjusting blade when the rotor is in the first position, and FIG. It is a figure which shows the rotation position of the light quantity adjustment blade when is in a 2nd position. The first position, the second position, and the third position of the rotor will be described in detail later.
In these figures, reference numeral 1 denotes a rotor made of a plastic magnet material having a substantially cylindrical magnet portion, and the magnet portion is magnetized to S and N poles alternately by dividing the outer peripheral surface into four in the circumferential direction. Yes. Specifically, as shown in FIG. 3, the magnetized portions 1a and 1c are magnetized with an N-pole outer peripheral surface, and the magnetized portions 1b and 1d are magnetized with an S-pole outer peripheral surface. In the first embodiment, the number of magnetic poles is four, but it may be two or more. A drive pin 1g extending in the axial direction is integrally formed on the magnet of the rotor 1. The drive pin 1g has its movement range restricted by a guide groove 5b of the base plate 5 described later. The drive device of the light quantity adjusting device is arranged so that the drive pin 1g moves in the direction toward and away from the center of the opening 5a of the base plate 5, that is, in the radial direction of the base plate 5.
A cylindrical coil 2 is wound around the bobbin 3. The coil 2 is concentric with the rotor 1 and arranged in a position adjacent to the rotor 1 in the axial direction, and the outer diameter of the coil 2 is substantially the same as the outer diameter of the magnet portion of the rotor 1. This drive device is a one-phase drive, and only one coil 2 needs to be provided.
Reference numeral 4 denotes a stator made of a soft magnetic material. The stator 4 includes an outer cylinder having tooth-shaped outer magnetic pole parts 4a and 4b formed at the tip and an inner cylinder 4c which is a cylindrical inner magnetic pole part. The outer magnetic pole portions 4a and 4b are configured to face the outer peripheral surface of the rotor 1 at a predetermined angle (see angle A in FIG. 3) with a predetermined gap. The angle here is Outer magnetic pole 4a, 4b and the center angle of the sector formed by the rotation center position of the magnet. The predetermined angle in the first embodiment will be described later. A cylindrical inner cylinder 4c of the stator 4 forms an inner magnetic pole part. The inner cylinder is configured to face the inner peripheral surface of the rotor 1 with a predetermined gap. The rotor 1, the coil 2, the bobbin 3, and the stator 4 constitute a drive device for operating the light amount adjusting device.
Reference numeral 5 denotes a base plate of the light amount adjusting device, which has an opening 5a at the center. A blade member is disposed in front of the opening 5a, and the amount of light passing through the opening 5a is adjusted by controlling the rotational position of the blade member. As shown in FIG. 2, the shaft portion 1 e of the rotor 1 is rotatably fitted in the recess 5 c of the base plate 5, and the shaft portion 1 f is rotatably fitted in the hole portion 4 d of the inner magnetic pole portion of the stator 4. The stator 4 is fixed to the base plate 5 at the outer magnetic pole portions 4a and 4b.
Reference numerals 6 and 7 denote light amount adjusting blades which are driven in accordance with the movement (rotation) of the drive pin 1g of the rotor 1 and change the opening area (for example, change the exposure amount) by covering the opening 5a. The round hole 6 a of the light quantity adjusting blade 6 is rotatably fitted to the protrusion 5 d of the base plate 5, and the long hole 6 b is slidably fitted to the drive pin 1 g of the rotor 1. Similarly, the round hole 7a of the light quantity adjusting blade 7 is rotatably fitted to the protrusion 5e of the base plate 5, and the long hole 7b is slidably fitted to the drive pin 1g of the rotor 1. Thereby, in conjunction with the movement of the drive pin 1g of the rotor 1, the light quantity adjusting blade 6 rotates about the axis of the round hole 6a, and the light quantity adjusting blade 7 rotates about the axis of the round hole 7a.
FIG. 6 shows the state of the light amount adjusting blades 6 and 7 when the coil 2 is not energized and the rotor is in the third position (the state shown in FIG. 3). The amount of light passing through the opening 5 a of the base plate 5 is shown. This is a state in which a predetermined amount is decreased. FIG. 7 shows the state of the light quantity adjusting blades 6 and 7 when the coil 1 is energized in a certain direction and the rotor 1 is in the first position (the state shown in FIG. 4). Is in a state retracted from the opening 5 a of the main plate 5. 8 shows the state of the light quantity adjusting blades 6 and 7 when the coil 1 is energized in the reverse direction and the rotor 1 is in the second position (the state shown in FIG. 5). It exists in the state which covers the opening part 5a of the ground plane 5. FIG.
That is, the light amount adjusting blades 6 and 7 play a role of changing the amount of light passing through the opening 5 a of the base plate 5 depending on the stop position of the rotor 1. Specifically, there are three states: a first state that is retracted from the opening 5a, a second state that covers the opening 5a, and a third state that is intermediate between the first state and the second state. Is changed to change the opening area formed by the light amount adjusting blades 6 and 7, and the amount of light passing through the opening 5a is adjusted.
Reference numeral 8 denotes a cover for preventing the light quantity adjusting blades 6 and 7 from coming off in the axial direction, and is fixed to the main plate 5.
FIG. 3 shows the rotational position of the rotor 1 that is held by the cogging force generated by the magnet portion of the rotor 1 and the outer magnetic pole portions 4 a and 4 b without energizing the coil 2. When the coil 2 is energized from the state of FIG. 3 and the outer magnetic pole parts 4a and 4b of the stator 4 are excited to the S pole and the inner magnetic pole part to the N pole, the rotor 1 rotates clockwise and the drive pin 1g The state shown in FIG. 4 hits one end of the guide groove 5b. If the coil 2 is deenergized in this state, the rotor 1 returns to the state shown in FIG. When the coil 2 is energized in the opposite direction from the state shown in FIG. 3 to excite the outer magnetic pole portions 4a and 4b of the stator 4 to the N pole and the inner magnetic pole portion 4c to the S pole, the rotor 1 in FIG. Rotating counterclockwise, the state shown in FIG. 5 is reached in which the drive pin 1g hits the other end of the guide groove 5b. If the coil is de-energized from this state, it returns to the state shown in FIG. Thus, by switching the energization state to the coil 2, the drive pin 1g can be reciprocated between the three positions shown in FIGS. The stop position of the rotor 1 shown in FIG. 4 is the first position, the stop position of the rotor shown in FIG. 5 is the second position, and the stop position of the rotor 1 shown in FIG. 3 is the third position.
Since the shaft portions 1e and 1f and the drive pin 1g are integrally formed with the rotor 1 made of a plastic magnet material, the cost can be reduced and assembly errors can be reduced as compared with the case where the shaft portions 1e and 1f and the drive pin 1g are formed of separate parts. . Further, the outer magnetic pole portions 4a and 4b and the drive pin 1g of the rotor 1 are overlapped in the axial direction of the rotor 1, and the axial length L (see FIG. 2) of the substantially cylindrical drive device is obtained. Can be suppressed.
Further, since the outer magnetic pole portions 4a and 4b of the stator 4 are configured as tooth shapes extending in a direction parallel to the axial direction of the rotor 1 by providing a notch from the distal end portion of the outer cylinder, The diameter can be suppressed to the minimum dimension obtained by adding the magnetic gap and its own thickness to the diameter of the magnet portion of the rotor 1, and a very small diameter driving device can be obtained. As a result, the area of the parts arranged on the main plate 5 is very small and a compact drive device is obtained.
In addition, since the rotor 1 is sandwiched between the outer magnetic pole portion facing the outer peripheral surface of the rotor 1 and the inner magnetic pole portion facing the inner peripheral surface, a magnetic path with less magnetic resistance can be formed, and the coil 2 When energized, the magnetic lines of force from one magnetic pole part flow into the other magnetic pole part, so that many of the generated magnetic force lines act on the rotor 1 sandwiched between the magnetic pole parts. For this reason, the drive device has a high rotational output, and as a result, downsizing is facilitated. Further, since only one coil 2 is required, the energization control circuit is simplified and the cost can be reduced.
Next, the angle facing the rotor 1 per one of the outer magnetic pole portions 4a and 4b will be described in detail.
In the present embodiment, when the coil 2 is not energized, the rotational position of the rotor 1 is held at the third position shown in FIG. This will be described with reference to FIGS. 9 and 10. FIG.
In FIG. 9, the vertical axis represents the magnetic force generated between the outer magnetic pole portion and the inner magnetic pole portion acting on the rotor 1, and the horizontal axis represents the rotational phase of the rotor 1.
The points indicated by the points E1, E2, and E3 indicate that when the rotor 1 tries to rotate forward, a force to reversely rotate the rotor 1 acts, and when the rotor 1 tries to reversely rotate, the rotor 1 becomes normal. The force which is going to rotate acts, and the rotor 1 is returned to the original position. At the points E1, E2, or E3, the rotor 1 is stably positioned by the magnetic force between the magnet and the outer magnetic pole portion. Points F1 and F2 are stop positions in an unstable equilibrium state in which a rotating force is applied to the positions of the front and rear E1, E2 and E3 points when the phase of the magnet is slightly shifted. When the coil 2 is not energized, it does not stop at points F1 and F2 due to vibrations or changes in posture, but stops at the point E1, E2 or E3.
Cogging stable points such as points E1, E2, and E3 exist with a period of (360 / NA) degrees, where the number of magnetized magnetic poles is NA, and the intermediate positions are uncertain such as points F1 and F2. Become a fixed point.
As a result of the numerical simulation by the finite element method, the angle per one pole where the magnet is magnetized (the central angle of the magnetized portion of the magnet) and the opposing angle facing the magnet of the outer magnetic pole (shown by A in FIG. 3) Yes, according to the relationship between the outer magnetic pole portion 3a and the fan-shaped central angle formed by the rotational center position of the magnet), the attraction state between the outer magnetic pole portion and the magnet when the coil is not energized It became clear that the state of changed.
According to this, the cogging position of the magnet changes depending on the angle of the outer magnetic pole portion facing the magnet. That is, when the angle of the outer magnetic pole portion facing the magnet is equal to or smaller than a predetermined value, the center of the magnet pole is stably held at a position facing the center of the outer magnetic pole portion. That is, the points E1, E2, and E3 described in FIG. 9 are in this state. Conversely, when the angle of the outer magnetic pole portion facing the magnet exceeds a predetermined value, the boundary between the poles of the magnet is stably held at a position facing the center of the outer magnetic pole portion, and this position is shown in FIG. The points E1, E2, and E3 described in the above are used. This will be described with reference to FIG.
FIG. 10 is a diagram showing the relationship between the width dimension of the outer magnetic pole part, the cogging force, and the magnet dimension.
In FIG. 10, the horizontal axis is “magnet thickness / perimeter length per rotor pole”, and the vertical axis is “opposite angle with respect to magnet per outer magnetic pole portion / angle per rotor pole” (in other words, “ The central angle per pole of the outer magnetic pole part / the central angle per pole of the magnet ").
For example, when the outer diameter of the magnet is 10 mm, the inner diameter is 9 mm, and the number of poles is 16, the thickness of the magnet is “(10−9) / 2” and the outer peripheral length per magnetized pole is “ Since “10 × π / 16”, the value of “magnet thickness / periphery length per rotor pole” on the horizontal axis is 0.255. Also, if the opposing angle to the magnet per outer magnetic pole part is 13 degrees, the angle per rotor pole is 22.5 degrees, so the vertical axis “the opposing angle to the magnet per outer magnetic pole part / The angle per rotor pole is 0.578.
Each point in FIG. 10 indicates that when the cogging force is almost zero or the minimum, “the angle of the motor facing the magnet per outer magnetic pole part / the angle per pole of the rotor” and “the thickness of the magnet / the rotor 1”. 11 is a plot of the “peripheral length per pole”, and is a graph of the nine types of motors shown in FIG. 11.
In FIG. 10, the vertical axis is “Y = angle of the outer magnetic pole portion with respect to the magnet / angle per rotor pole”, and the horizontal axis is “X = magnet thickness / periphery length per rotor pole”. These points exist in a region surrounded by a straight line 1 approximated by an expression “Y = −0.3X + 0.63” and a straight line 2 approximated by an expression “Y = −0.3X + 0.72”. .
The range below the straight line 1 in the figure, that is, the range of “Y <−0.3X + 0.63” is stably held at a position where the center of the pole of the magnet faces the center of the outer magnetic pole portion. If 3X + 0.72 <Y, the magnet pole is stably held at a position where the boundary between the poles faces the center of the outer magnetic pole portion.
When the region surrounded by the straight line 1 and the straight line 2, that is, the condition “−0.3X + 0.63 ≦ Y ≦ −0.3X + 0.72” is satisfied, the cogging force is extremely small.
Here, if each opposing angle A with respect to the magnet of the outer magnetic pole portions 4a and 4b gradually changes depending on the axial position of the magnet, the average opposing angle should satisfy the above conditional expression. It ’s fine. That is, if the facing angle A near the end face of the magnet is 15 degrees, for example, and the facing angle A near the tip of the outer magnetic pole part is about 13 degrees, the average value of 14 degrees is applied to the above conditional expression. Just do it.
The experimental results are shown in FIG. 12, FIG. 13, and FIG.
12, 13, and 14, as in FIG. 9, the vertical axis indicates the torque due to the magnetic force generated by the outer magnetic pole portion and the inner magnetic pole portion acting on the rotor 1, and the horizontal axis indicates the rotational phase of the rotor 1. . This shows the torque when no power is supplied to the coil, that is, the torque generated when a voltage of 3 V is applied between the coking torque and the coil terminal.
This model motor is
・ The magnet has an outer diameter of 10.6mm, an inner diameter of 9.8mm, and 16 poles.
・ The coil has 112 turns and 10Ω resistance
-The outer magnetic pole part of the stator has an outer diameter of 11.6 mm and an inner diameter of 11.1 mm.
-The inner magnetic pole part of the stator has an outer diameter of 9.3 mm and an inner diameter of 8.8 mm.
It is composed of The shape of the motor is the same as that shown in FIGS.
In FIG. 12, each opposing angle A with respect to the magnet of the outer magnetic pole portion is 10.35 degrees. The values of X and Y are X = 0.192 and Y = 0.46.
In FIG. 13, each opposing angle A with respect to the magnet of the outer magnetic pole portion is 13.45 degrees. In this case, the torque generated when no power is supplied, that is, the coking torque is the smallest. The values of X and Y are X = 0.192 and Y = 0.60.
In FIG. 14, each opposing angle A with respect to the magnet of the outer magnetic pole portion is 15.52 degrees. The values of X and Y are X = 0.192 and Y = 0.69.
The configuration shown in FIGS. 12, 13, and 14 is indicated by points a, b, and c on FIG. 15 showing the straight lines obtained in FIG.
In the configuration having the characteristics shown in FIG. 12, that is, the angle A facing the magnet of the outer magnetic pole portion is 10.35 degrees, X = 0.192, Y = 0.46, and “Y <−0.3X + 0”. .63 ", and the stable position of the magnet was such that the center of the pole of the magnetized part was opposed to the center of the outer magnetic pole part.
13 having the characteristics shown in FIG. 13, that is, with the outer pole portion facing the magnet at an angle A of 13.45 degrees, X = 0.192, Y = 0.60, and “−0.3X + 0.63”. The condition of “≦ Y ≦ −0.3X + 0.72” is satisfied, and the coking torque is extremely small.
In the configuration having the characteristics shown in FIG. 14, that is, the angle A of the outer magnetic pole portion facing the magnet is 15.52 degrees, X = 0.192, Y = 0.69, and “−0.3X + 0.72”. The condition of <Y ”was satisfied, and the stable position of the magnet was a position where the pole boundary of the magnetized portion was opposed to the center of the outer magnetic pole portion.
In the present embodiment, the dimensions are set to be “−0.3X + 0.72 <Y”, and in the state of FIG. 3 in which the coil 2 is not energized, the E1 point shown in FIG. The points E2 and E3 are stopped stably at a position where the pole Q of the magnet part of the rotor 1 and the pole boundary Q1 face the center R1 of the outer magnetic pole parts 4a and 4b.
Here, it is desirable that the facing angle A of the outer magnetic pole portions 4a and 4b with respect to the outer peripheral surface of the magnet portion is set in consideration of component dimensional tolerance, fitting play, and the like. That is, in the above case, for example, even if the Y value of the outer magnetic poles 4a and 4b is set to be large, theoretically, the boundary between the poles of the magnet is stably held at the position facing the center of the outer magnetic pole parts 4a and 4b. However, in consideration of component crossing, there is little guarantee that the boundary between the poles of the magnet can always be stably held at a position facing the center of the outer magnetic pole portions 4a and 4b. Therefore, it is necessary to set the outer magnetic pole part with a little more margin, but if the opposing angle A of the outer magnetic pole part is increased more than necessary, the cogging force tends to increase too much and the rotational torque tends to decrease. It is necessary to set by looking at the balance point of the required torque.
When the coil 2 is energized from the state shown in FIG. 3, the rotor 1 rotates in an attempt to oppose the center of the magnet pole and the center position of the outer magnetic pole portions 4 a and 4 b. If the rotor 1 is rotated until the center of the magnet pole and the center position of the outer magnetic pole portions 4a and 4b face each other at this time, the rotor 1 is positioned at points F1 and F2 in FIG. Become. Therefore, when energization of the coil 2 is stopped, equal force is applied to the magnet in both rotation directions, and the rotor 1 does not necessarily return to the state shown in FIG.
Therefore, in the present embodiment, the relationship between the guide groove 5b of the main plate 5 and the drive pin 1g of the rotor 1 is set as follows, and the center of the pole of the rotor 1 and the center of the outer magnetic pole portions 4a and 4b face each other. The rotor 1 is prevented from rotating to the position.
The rotational position of the rotor 1 shown in FIG. 3 is assumed to be the position of point E2 in FIG. As shown in FIG. 4, when the drive pin 1g is in contact with one end face of the guide groove 5b, the center R1 of Q1 that is the boundary between the poles of the magnet part of the rotor 1 and the outer magnetic pole part 4a (the same applies to 4b). Is set to be β degrees (≠ 0 degrees). When the rotational position of the rotor 1 at this time is applied to FIG. 9, it becomes the position of the point H, and is a position between the point E2 and the point F2 adjacent thereto. The cogging force at this position (the attractive force generated between the stator 4 acting on the magnet portion of the rotor 1) is T2, and the force acts in the rotational direction in which the rotor 1 tries to return to the point E2.
As shown in FIG. 5, when the drive pin 1g is in contact with the other end face of the guide groove 5b, the center R1 of Q1 which is the boundary part between the poles of the magnet part of the rotor 1 and the outer magnetic pole part 4a (the same applies to 4b). Is set to be α degrees (≠ 0 degrees). When the rotational position of the rotor 1 at this time is applied to FIG. 9, it becomes the position of the point G, and is a position between the point E2 and the point F1 adjacent thereto. Even at this position, the cogging force is T1, and the force acts in the rotational direction in which the rotor 1 tries to return to the point E2.
In other words, the rotation angle of the rotor 1 includes a range in which the cogging force acting on the magnet portion of the rotor 1 is in the opposite direction, and the magnet portion of the rotor 1 Polar center It can be said that the setting is made so as not to include a range in which the center position of the outer magnetic pole portion faces each other.
With this configuration, the rotor 1 rotates between the first position shown in FIG. 4 and the second position shown in FIG. 5 by switching the energization direction to the coil 2, and from either position. When the coil 2 is de-energized, the rotor 1 returns to the third position shown in FIG.
The light quantity adjusting blades 6 and 7 rotate in conjunction with the rotor 1. As described above, when the magnet portion of the rotor 1 is in the first position shown in FIG. 4, the light amount adjusting blades 6, 7 are each retracted from the opening 5 a of the base plate 5 as shown in FIG. 7. At this time, the amount of opening formed by the light quantity adjusting blades 6 and 7 is maximized. When the magnet portion of the rotor 1 is in the second position shown in FIG. 5, the light quantity adjusting blades 6 and 7 are in a position to close the opening 5a as shown in FIG. At this time, the opening amount formed by the light amount adjusting blades 6 and 7 is minimized. When the magnet portion of the rotor 1 is in the third position shown in FIG. 3, the light quantity adjusting blades 6 and 7 are in a position to block a part of the opening 5a as shown in FIG. At this time, the amount of open light formed by the light amount adjusting blades 6 and 7 is about half that in FIG. Therefore, by changing the energization direction and the energization direction of the coil 2, the light quantity adjusting blades 6 and 7 are in the open state, the intermediate aperture state, and the closed state (one of FIGS. 6 to 8) with respect to the opening 5 a. The amount of light passing through the opening 5a of the main plate 5 can be adjusted. Further, when the coil 2 is not energized, the position of the intermediate diaphragm is held by the attractive force of the rotor, the magnet part, and the outer magnetic pole parts 4a and 4b. In the first embodiment, two outer magnetic pole portions are provided, but one may be used.
In the first embodiment, a light amount adjusting blade (aperture aperture blade) is exemplified as the light amount adjusting member and the opening area thereof is changed. However, the present invention is not limited to this. The light amount adjustment blade may be a shutter blade, or a light amount adjustment filter plate that adjusts the amount of light passing through an ND filter with a different density by moving forward and backward. In the first embodiment, the drive device is installed so that the optical axis and the rotation axis of the drive device are parallel to each other. However, the drive device may not be installed in parallel. Further, the driven body may be other members than the blade member such as the diaphragm blade and the shutter blade.
FIG. 16 is a perspective view of a lens driving device according to the second embodiment of the present invention. This is a device for driving the lens in the optical axis direction. The drive device composed of the rotor 1, the coil 2, the bobbin 3, and the stator 4 is substantially the same as the first embodiment except that the arm 1h extending in the radial direction is provided on the rotor and 1g is provided at the tip thereof. A configuration is used.
In FIG. 16, 10 is a lens holder, and 11 is a lens fixed to the lens holder 10. Reference numerals 12 and 13 denote shafts provided in parallel with the optical axis of the lens 11 in order to provide guidance when the lens holder 10 moves. The shafts 12 and 13 are arranged in a direction orthogonal to the rotation axis of the rotor of the drive device.
The fitting portion 10a and the fitting portion 10b of the lens holder 10 are slidably fitted to the shaft 12 and the shaft 13, and can reciprocate along the shaft. The lens holder 10 has an arm portion 10c, and a sliding portion 10d is provided at the tip thereof. The driving pin 1g of the rotor 1 is slidably fitted to the sliding portion 10d, and the driving pin 1g is moved. Accordingly, the lens holder 10 moves in the optical axis direction.
Since the drive device is the same as the drive device described in the first embodiment, the drive pin 1g of the rotor 1 is stopped at three positions by switching whether or not the coil 2 is energized and the energization direction. The lens can be held at three positions in conjunction with this. By moving the lens in a direction parallel to the optical axis, a lens driving device capable of arbitrarily selecting three focal lengths can be obtained. In addition, when one of the focal lengths is selected, the lens position is maintained by the cogging force without energizing the coil, which leads to power saving.
The rotor drive pin 1g and the arm 1h provided with the drive pin 1g may be provided as separate parts that move in conjunction with the magnet portion without being molded integrally with the magnet portion of the rotor.
Alternatively, the driving device may be arranged such that the rotation axis of the driving device is parallel to the optical axis of the lens, and the lens is moved in a direction perpendicular to the optical axis. If three different types of lenses are shifted and arranged in the lens holder, a lens driving device that can select three types of lenses according to the rotation of the rotor can be configured.
As described above, according to the present invention, the operating range of the rotor is increased. The range in which the cogging force acting on the magnet portion of the rotor is in the opposite direction by switching the energization direction to the coil Including the center of the magnetized pole of the magnet portion and the outer magnetic pole portion The center of Is set to a range that does not include the opposing region, and the center angle per pole of the outer magnetic pole part is set within the operating range of the rotor, and the center of the magnetized pole and the outer magnetic pole part The center of Is set to an angle that does not oppose, and the ratio of the center angle per pole of the outer magnetic pole part to the center angle per pole of the magnet part magnetized is Y, and the ratio of the magnet part to the radial thickness of the magnet part The ratio of the circumferential length per magnetized pole is X, and the drive unit is set so as to satisfy −0.3X + 0.72 <Y. Thus, the cogging force acts so that the boundary between the pole and the pole faces the center position of the outer magnetic pole.
Therefore, when the coil is not energized, the rotor is positioned at the position where the boundary between the pole of the magnet and the pole is opposed to the outer magnetic pole by the cogging force acting between the magnet and the pole of the rotor. It is possible to provide a simple drive device, light amount adjustment device, or lens drive device that is held and can rotate the rotor in a direction corresponding to the energization direction of the coil and has three stop positions.
FIG. 1 is an exploded perspective view of a light amount adjusting device according to a first embodiment of the present invention.
FIG. 2 is a cross-sectional view of the light amount adjusting device of FIG.
3 is a cross-sectional view taken along the line BB of FIG. 2 when the rotor is in a third position in the first embodiment of the present invention.
4 is a cross-sectional view taken along the line BB in FIG. 2 when the rotor is in the first position in the first embodiment of the invention.
5 is a cross-sectional view taken along the line BB of FIG. 2 when the rotor is in the second position in the first embodiment of the present invention.
FIG. 6 is a diagram showing a rotational position of a light quantity adjustment blade when the rotor is in a third position in the first embodiment of the present invention.
FIG. 7 is a diagram showing a rotational position of a light quantity adjustment blade when the rotor is in the first position in the first embodiment of the present invention.
FIG. 8 is a diagram showing a rotational position of a light quantity adjusting blade when the rotor is in a second position in the first embodiment of the present invention.
FIG. 9 is a diagram illustrating a state of cogging force according to the first embodiment of the present invention.
FIG. 10 is a diagram showing the relationship between the width dimension of the outer magnetic pole, the cogging force, and the magnet dimension in the first embodiment of the present invention.
11 is a diagram showing the types of motors used to obtain the relationships in FIG.
FIG. 12 is a diagram showing the relationship between the torque and the rotational phase of the rotor, which are experimental results in the first embodiment of the invention.
FIG. 13 is a diagram showing the relationship between the torque and the rotational phase of the rotor, which are experimental results in the first embodiment of the invention.
FIG. 14 is a diagram showing the relationship between the torque and the rotational phase of the rotor, which are experimental results in the first embodiment of the invention.
FIG. 15 is a diagram illustrating the relationship between the width dimension of the outer magnetic pole, the cogging force, and the magnet dimension in the experimental model according to the first embodiment of the present invention.
FIG. 16 is a perspective view of a lens driving device according to a second embodiment of the present invention.
FIG. 17 shows a conventional shutter blade driving device.
FIG. 18 shows another conventional shutter blade driving device.
5 Ground plane
6,7 Light quantity adjustment blade
12,13 shaft
The outer peripheral surface is divided in the circumferential direction and has a cylindrical magnet portion magnetized with different poles. The rotor is rotatable around an axis, and is formed by extending in the axial direction and the magnet portion. At least one outer magnetic pole portion facing the outer circumferential surface of the magnetic pole portion, an inner magnetic pole portion facing the inner circumferential surface of the magnet portion at a position facing the outer magnetic pole portion, and disposed in the axial direction of the rotor, A driving device having an outer magnetic pole part and a coil for exciting the inner magnetic pole part,
The operating range of the rotor includes a range in which the cogging force acting on the magnet portion of the rotor is in the opposite direction by switching the energization direction to the coil , and the center of the magnetized pole of the magnet portion And a range that does not include a region where the center of the outer magnetic pole portion is opposed,
The central angle per pole of the outer magnetic pole part is set to an angle in which the center of the magnetized pole of the magnet part and the center of the outer magnetic pole part do not face each other within the operating range of the rotor,
The value of the ratio of the center angle per pole of the outer magnetic pole part to the center angle per pole of the magnet part magnetized is Y, and the magnetized 1 of the magnet part relative to the radial thickness of the magnet part If the value of the ratio of lengths on the circumference per pole is X, −0.3X + 0.72 <Y
A drive device characterized by satisfying the following conditions.
2. The drive device according to claim 1, wherein the rotor rotates in the opposite direction by switching a direction of energization of the coil, with a stop position when the coil is not energized as a boundary.
3. The drive device according to claim 1, wherein the outer magnetic pole portion is formed in a tooth shape extending in an axial direction of the rotor by providing a notch from a tip portion of a cylinder.
One end of the shaft, which is the center of rotation of the rotor, rotates in a hole provided on the ground plate off the opening of the ground plate, and the other end rotates in a hole provided in the central portion of the inner magnetic pole part. The drive device according to claim 1, wherein the drive device is fitted.
A rotor having a cylindrical magnet portion whose outer peripheral surface is divided in the circumferential direction and magnetized with different poles, rotatable about an axis, an output member that operates according to the rotation of the rotor, and the axial direction And at least one outer magnetic pole portion facing the outer peripheral surface of the magnet portion, and an inner magnetic pole facing the inner peripheral surface of the magnet portion at a position facing the outer magnetic pole portion , A coil that is arranged in the axial direction of the rotor and that excites the outer magnetic pole part and the inner magnetic pole part, a ground plate having an opening, and is driven by the output member to advance and retract to the opening of the ground plate A light amount adjusting device having a light amount adjusting member that changes the amount of light passing through the opening,
The light quantity adjusting device characterized by satisfying the following conditions.
The light quantity adjusting device according to claim 5 , wherein the rotor rotates in the opposite direction by switching the direction of energization to the coil with a stop position when the coil is not energized as a boundary.
The light quantity adjusting device according to claim 5 or 6, wherein the outer magnetic pole portion is formed in a tooth shape extending in an axial direction of the rotor by providing a notch from a tip portion of a cylinder. .
One end of the shaft that is the center of rotation of the rotor is in a hole provided on the ground plate that is out of the opening of the ground plate, and the other end is in a hole provided in the central portion of the inner magnetic pole part. The light amount adjusting device according to any one of claims 5 to 7, wherein the light amount adjusting device is rotatably fitted.
A rotor having a cylindrical magnet portion whose outer peripheral surface is divided in the circumferential direction and magnetized with different poles, rotatable about an axis, an output member that operates according to the rotation of the rotor, and the axial direction And at least one outer magnetic pole portion facing the outer peripheral surface of the magnet portion, and an inner magnetic pole facing the inner peripheral surface of the magnet portion at a position facing the outer magnetic pole portion , A coil that is arranged in the axial direction of the rotor and that excites the outer magnetic pole part and the inner magnetic pole part, a ground plate having an opening, and is driven by the output member to advance and retract to the opening of the ground plate A lens driving device having a lens that changes a focal length of a light beam passing through the opening,
A lens driving device characterized by satisfying the following conditions.
JP2003186277A 2002-07-29 2003-06-30 Driving device, light amount adjusting device, and lens driving device Expired - Fee Related JP4401696B2 (en)
JP2002219361 2002-07-29
JP2003186277A JP4401696B2 (en) 2002-07-29 2003-06-30 Driving device, light amount adjusting device, and lens driving device
US10/625,077 US6798987B2 (en) 2002-07-29 2003-07-22 Driving apparatus, light-amount regulating apparatus, and lens driving apparatus
MYPI20032816 MY128518A (en) 2002-07-29 2003-07-25 Driving apparatus, light-amount regulating apparatus, and lens driving apparatus
CN 03149845 CN1284292C (en) 2002-07-29 2003-07-28 Driving gear, fader and lens driving gear
KR20030052213A KR100552557B1 (en) 2002-07-29 2003-07-29 Driving apparatus, light-amount regulating apparatus, and lens driving apparatus
JP2004129485A JP2004129485A (en) 2004-04-22
JP4401696B2 true JP4401696B2 (en) 2010-01-20
ID=32032741
JP2003186277A Expired - Fee Related JP4401696B2 (en) 2002-07-29 2003-06-30 Driving device, light amount adjusting device, and lens driving device
US (1) US6798987B2 (en)
JP (1) JP4401696B2 (en)
KR (1) KR100552557B1 (en)
CN (1) CN1284292C (en)
MY (1) MY128518A (en)
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2003-06-30 JP JP2003186277A patent/JP4401696B2/en not_active Expired - Fee Related
2003-07-22 US US10/625,077 patent/US6798987B2/en not_active Expired - Fee Related
2003-07-25 MY MYPI20032816 patent/MY128518A/en unknown
2003-07-28 CN CN 03149845 patent/CN1284292C/en not_active IP Right Cessation
2003-07-29 KR KR20030052213A patent/KR100552557B1/en not_active IP Right Cessation
JP2004129485A (en) 2004-04-22
KR20040011379A (en) 2004-02-05
US6798987B2 (en) 2004-09-28
MY128518A (en) 2007-02-28
US20040126106A1 (en) 2004-07-01
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