Rotary drive device

Abstract

To provide a rotary drive device capable of rotating and driving a drive shaft with high accuracy.SOLUTION: The rotary drive device 10 includes a base plate 3, a drive shaft 20 rotatable with respect to the base plate, an electromagnetic drive part 25 for rotating the drive shaft, and a vibration unit 30 for applying vibration to the drive shaft. The vibration unit includes a movable part 32 which has a contact part capable of coming into contact with the drive shaft and is movable with respect to the base plate, and an electromagnetic coil and a magnet which repeat contact of the contact part with the drive shaft and separation from the drive shaft by moving the movable part.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a rotary drive device. [Background technology]

[0002] Rotary drive mechanisms that rotate drive shafts are used in a variety of machines and devices. For example, in a camera shutter device, a rotary drive mechanism is used to rotate a lever that drives the shutter (see, for example, Patent Document 1). In recent years, high-precision control has been required in various fields, and it has become necessary to rotate drive shafts with higher precision in rotary drive mechanisms as well. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 6-148718 Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention has been made in view of the above problems of the prior art, and has as its object to provide a rotary drive device that is capable of rotating a drive shaft with high precision. [Means for solving the problem]

[0005] According to a first aspect of the present invention, there is provided a rotary drive device capable of rotating a drive shaft with high precision, the rotary drive device comprising: a fixed part, a drive shaft rotatable relative to the fixed part, a first drive part that rotates the drive shaft, a vibration unit that applies vibration to the drive shaft, the vibration unit including a movable part having a contact part that can come into contact with the drive shaft and that is movable relative to the fixed part, and a second drive part that moves the movable part to repeatedly bring the contact part into contact with and out of contact with the drive shaft.

[0006] According to a second aspect of the present invention, there is provided a rotation drive device capable of rotating a drive shaft with high precision, the rotation drive device comprising: a fixed part, a drive shaft rotatable relative to the fixed part, a drive part for rotating the drive shaft, a sensor disposed at an end of the drive shaft, a circuit board disposed on the fixed part, and a flexible wiring board connecting the sensor and the circuit board, the flexible wiring board including a first connection part connected to the sensor, a first upright part extending from the first connection part in the axial direction of the drive shaft beyond the circuit board, a second connection part connected to the circuit board, a second upright part extending from the second connection part in the axial direction, and a coupling part connecting the first upright part and the second upright part, the coupling part absorbing twisting that occurs between the first upright part and the second upright part as the drive shaft rotates. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a plan view showing a shutter incorporating a rotary drive device according to one embodiment of the present invention. [Figure 2] FIG. 2 is a perspective view showing a part of the shutter shown in FIG. [Figure 3] 3 is an enlarged left side view of a part of the shutter shown in FIG. [Figure 4A] 4A is a bottom view of the base portion of the vibration unit shown in FIG. 3. FIG. [Figure 4B] FIG. 4B is a cross-sectional view taken along line AA in FIG. 4A. [Figure 5A] 5A is a plan view of a movable part of the vibration unit shown in FIG. [Figure 5B] FIG. 5B is a cross-sectional view taken along line BB in FIG. 5A. [Figure 5C] FIG. 5C is a bottom view of the movable portion shown in FIG. 5A. [Figure 6] FIG. 6 is an exploded perspective view showing a sensor unit of the shutter shown in FIG. [Figure 7A]7A is a perspective view showing the relationship between the flexible wiring board and the drive shaft of the sensor unit shown in FIG. 6. FIG. [Figure 7B] FIG. 7B is a plan view of FIG. 7A. [Figure 7C] FIG. 7C is a front view of FIG. 7A. [Figure 7D] FIG. 7D is a right side view of FIG. 7A. [Figure 8A] FIG. 8A is a plan view schematically showing the flexible wiring board in the state shown in FIG. [Figure 8B] 8B is a plan view schematically showing the flexible wiring board when it changes from the state shown in FIG. 1 to the state shown in FIG. 6. FIG. [Figure 8C] FIG. 8C is a plan view schematically showing a state in which the drive shaft has further rotated from the state shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, an embodiment of a rotation drive device according to the present invention will be described in detail with reference to FIGS. 1 to 8C. In FIGS. 1 to 8C, identical or corresponding components are designated by the same reference numerals, and redundant description will be omitted. In addition, in FIGS. 1 to 8C, the scale and dimensions of each component may be exaggerated or some components may be omitted. In the following description, unless otherwise specified, terms such as "first" and "second" are used only to distinguish components from one another and do not indicate a specific order or sequence.

[0009] Figure 1 is a front view showing a shutter 1 incorporating a rotary drive device according to one embodiment of the present invention. Below, an example in which the rotary drive device according to the present invention is applied to a camera shutter will be described, but the rotary drive device according to the present invention is not limited to camera shutters and can be applied to any device that includes a mechanism for rotationally driving a drive shaft. The shutter 1 shown in Figure 1 includes a base plate 3 in which a rectangular opening 2 is formed, a base plate 4 disposed on the +Z direction side of the base plate 3, a plurality of blades 5 that can open and close the opening 2, and two arms 6 and 7 connected to the blades 5.

[0010] FIG. 2 is a perspective view showing a portion of the shutter 1 shown in FIG. 1. In FIG. 2, the base plate 3 is shown transparently with dotted lines to facilitate understanding. As shown in FIG. 2, the shutter 1 includes a rotary drive device 10 that rotates the arm portion 6 to move the blades 5. This rotary drive device 10 includes a drive lever 21 having a drive shaft 20 that is rotatable relative to the base plate 3 (fixed portion), an electromagnetic drive unit 25 (first drive unit) that rotates the drive shaft 20, and a vibration unit 30 that imparts vibrations to the drive shaft 20. The drive lever 21 has a connecting portion 22 that is connected to the arm portion 6. The base plate 3 is formed with an arc groove 3A that extends along an arc centered on the drive shaft 20, and the connecting portion 22 moves along the arc groove 3A as the drive lever 21 rotates.

[0011] FIG. 3 is a left side view showing an enlarged portion of the shutter 1. As shown in FIG. 3, the end 20A of the drive shaft 20 has a reduced outer diameter, and this end 20A is supported by a bearing 23. An arm 6 is rotatably attached to the end 20A of the drive shaft 20 via a sleeve 24. As shown in FIG. 2, the arm 7 is rotatably attached to a support shaft 8 provided on the base plate 3. The arm 6 is connected to each of the blades 5 by a pin 6A, and the arm 7 is connected to each of the blades 5 by a pin 7A. Therefore, the blades 5 and the two arms 6, 7 form a link mechanism, and when the drive shaft 20 is rotationally driven by the rotary drive device 10, the arm 6 rotates by the drive lever 21, and the blades 5 move in the Y direction by the above-mentioned link mechanism.

[0012] Here, a lubricant such as lubricating oil or grease is injected between the drive shaft 20 and the bearing 23 to ensure smooth rotation of the drive shaft 20. However, if the drive shaft 20 is not rotated for a long time, the lubricant may harden, making it difficult for the drive shaft 20 to rotate. Also, a drop in temperature may harden the lubricant, making it difficult for the drive shaft 20 to rotate. In this way, the ease of rotation of the drive shaft 20 may differ depending on the timing of driving the drive shaft 20, the temperature, etc., and therefore the accuracy of the rotational drive of the drive shaft 20 may change depending on the conditions before the drive shaft 20 is rotated, such as the timing of driving the drive shaft 20 and the temperature.

[0013] In this embodiment, in order to prevent the accuracy of rotational driving of the drive shaft 20 from changing depending on the state of the drive shaft 20 before it is rotated, the vibration unit 30 applies vibration to the drive shaft 20 before it is rotated. That is, by applying vibration to the drive shaft 20 by the vibration unit 30 before it is rotated, the lubricant present between the drive shaft 20 and the bearing 23 is made fluid, so that even if the state of the drive shaft 20 before it is rotated is different, the state of the drive shaft 20 will be the same when it is rotated. Below, this vibration unit 30 will be described in detail.

[0014] 2 and 3, the vibration unit 30 includes a cover 31 fixed to the base plate 3, and a movable part 32 movable in the Y direction relative to the base plate 3. The cover 31 is fixed to the base plate 3 with screws 33. In this way, the movable part 32 is located between the base plate 3 and the cover 31, and therefore can stably move in the Y direction between the cover 31 and the base plate 3.

[0015] FIG. 4A is a bottom view of the cover 31, and FIG. 4B is a cross-sectional view taken along line AA in FIG. 4A. As shown in FIGS. 4A and 4B, the cover 31 includes a column portion 35 having a screw hole 34 for receiving a screw 33, and a main body 36 that covers the +Z direction side of the movable portion 32 at a position spaced from the base plate 3. Two recesses 37 are formed on the surface of the main body 36 facing in the -Z direction, and an electromagnetic coil 40 is housed inside the recesses 37. A protrusion 38 that protrudes in the -Z direction is formed at the center of each recess 37, and a magnetic sensor 41, such as a Hall element or a TMR sensor, is disposed on the top of the protrusion 38. The electromagnetic coil 40 is connected to a control unit 42 (schematically shown in FIG. 4A) disposed in a separate location, and the control unit 42 controls the supply of current to the electromagnetic coil 40. The magnetic sensor 41 is also connected to the control unit 42, and the output of the magnetic sensor 41 is processed and analyzed by the control unit 42. On both sides of the recess 37 in the X direction, hemispherical ball holes 39 in which balls 50 (see FIG. 3) are placed are formed.

[0016] FIG. 5A is a plan view of the movable part 32, FIG. 5B is a cross-sectional view taken along line BB in FIG. 5A, and FIG. 5C is a bottom view. As shown in FIGS. 5A to 5C, the movable part 32 includes a base part 60 located between the main body 36 of the cover 31 and the base plate 3, and an extension part 61 extending from the base part 60 in the +Y direction. A shaft hole 62 into which the drive shaft 20 (see FIG. 5B) is inserted is formed in the extension part 61, and a contact part 63 that can come into contact with the drive shaft 20 is provided on the inner periphery of this shaft hole 62. As shown in FIG. 5B, a small gap is formed between the drive shaft 20 and the contact part 63. The contact part 63 is preferably made of an elastic material such as rubber or resin to absorb impact caused by contact with the drive shaft 20.

[0017] 5A, two magnets 66 are embedded on a plate yoke 65 on the surface of the base 60 on the +Z direction side. The magnets 66 are placed adjacent to the electromagnetic coil 40, and the magnetic sensor 41 disposed on the cover 31 described above is configured to be able to detect the position of the movable part 32 by detecting a change in the magnetic field caused by the movement of the magnets 66 of the movable part 32.

[0018] As shown in FIG. 5A, four guide grooves 64 extending in the Y direction are formed on the surface of the base 60 on the +Z direction side. Furthermore, as shown in FIG. 5C, four guide grooves 67 extending in the Y direction are also formed on the surface of the base 60 on the −Z direction side. As shown in FIG. 3, the balls 50 disposed in the ball holes 39 of the cover 31 are positioned in each of the guide grooves 64. Furthermore, the balls 51 disposed in hemispherical ball holes formed in the base plate 3 are positioned in each of the guide grooves 67. This configuration allows the balls 50 disposed in the ball holes 39 of the cover 31 and the balls 51 disposed in the ball holes of the base plate 3 to move while rolling within the guide grooves 64, 67, respectively. This allows the movable part 32 to move in the Y direction relative to the base plate 3.

[0019] In the vibration unit 30 configured as described above, when a current is passed through the electromagnetic coil 40 of the cover 31 in the magnetic field generated by the magnet 66 of the movable part 32, a force is generated in the movable part 32 in the Y direction according to Fleming's left-hand rule, causing the movable part 32 to move in the Y direction. In this embodiment, the control unit 42, prior to driving the electromagnetic drive unit 25 to rotate the drive shaft 20, passes current through the electromagnetic coil 40 of the vibration unit 30 to move the movable part 32, for example, in the +Y direction, pressing the contact part 63 against the drive shaft 20. Then, by reversing the direction of the current flowing through the electromagnetic coil 40, the movable part 32 moves, for example, in the -Y direction, causing the contact part 63 to separate from the drive shaft 20. By switching the direction of the current flowing through the electromagnetic coil 40 of the vibration unit 30, the control unit 42 repeatedly causes the contact part 63 to contact and separate from the drive shaft 20, thereby vibrating the drive shaft 20. For example, the drive shaft 20 may be vibrated for a period of 10 microseconds to 20 milliseconds. In this way, the electromagnetic coil 40 and the magnet 66 in this embodiment function as a second driving part that repeatedly brings the contact part 63 into contact with and away from the drive shaft 20 by moving the movable part 32.

[0020] In this way, vibrations can be applied to the drive shaft 20 by repeatedly bringing the contact portion 63 of the vibration unit 30 into contact with and out of contact with the drive shaft 20, so that even if the lubricant between the drive shaft 20 and the bearing 23 has solidified before the drive shaft 20 is rotated, the fluidity of the lubricant can be increased by the vibrations caused by the vibration unit 30. In other words, by using the vibration unit 30 of this embodiment, the drive shaft 20 can always be rotated in the same state regardless of the state of the drive shaft 20 before it is rotated, so that fluctuations in the accuracy of the rotation of the drive shaft 20 depending on the state of the drive shaft 20 before it is rotated are suppressed, and the drive shaft 20 can be rotated with high accuracy.

[0021] Returning to Fig. 1, the rotary drive device 10 in this embodiment includes a sensor unit 70 that can accurately detect the rotation angle of the drive shaft 20. Fig. 6 is an exploded perspective view showing the sensor unit 70. For ease of understanding, Fig. 6 shows a state in which the drive shaft 20 has rotated slightly clockwise from the state shown in Fig. 1.

[0022] As shown in FIG. 6, the sensor unit 70 includes a base plate 72 fixed to the base plate 4 (fixing portion) with screws 71 (see FIG. 1), a set of magnets 74 disposed inside a recess 73 formed in the base plate 72, a circuit board 75 disposed on the magnets 74, a magnetic sensor 76 disposed at the end of the drive shaft 20, and a flexible wiring board 80 connecting the magnetic sensor 76 and the circuit board 75. The magnetic sensor 76 may be, for example, a Hall element or a TMR sensor. The magnetic sensor 76 is connected to the control unit 42 (see FIG. 4A), and the output of the magnetic sensor 76 is processed and analyzed by the control unit 42. When the drive shaft 20 rotates, the magnetic sensor 76 rotates relative to the magnet 74. The magnetic sensor 76 detects changes in the magnetic field due to this relative rotation, thereby enabling highly accurate detection of the rotation angle of the drive shaft 20.

[0023] 7A is a perspective view showing the relationship between the flexible wiring board 80 and drive shaft 20 shown in FIG. 6, FIG. 7B is a plan view, FIG. 7C is a front view, and FIG. 7D is a right side view. As shown in FIGS. 7A to 7D, the flexible wiring board 80 includes a disk-shaped first connection portion 81 located between the magnetic sensor 76 and the drive shaft 20, four first upright portions 82 extending from the first connection portion 81 in the axial direction of the drive shaft 20, four second connection portions 83 connected to contacts 75A (see FIG. 6) of the circuit board 75, four second upright portions 84 extending in the axial direction from the second connection portion 83, and four connecting portions 85 connecting the first upright portions 82 and the second upright portions 84. The wiring in the flexible wiring board 80 is connected to the magnetic sensor 76 at the first connection portion 81 and is connected to the wiring in the circuit board 75 at the second connection portion 83. The first upright portion 82 extends from the first connection portion 81 in the axial direction beyond the circuit board 75 to the same height as the second upright portion 84 .

[0024] Each connecting portion 85 includes a first shape-retaining portion 86 that is connected to the first upright portion 82 and maintains its shape while the drive shaft 20 rotates, a second shape-retaining portion 87 that is connected to the second upright portion 84 and maintains its shape while the drive shaft 20 rotates, and a bending portion 88 that bends between the first shape-retaining portion 86 and the second shape-retaining portion 87 as the drive shaft 20 rotates. Each bending portion 88 has one or more folds and is configured to bend at these folds. In this embodiment, each bending portion 88 has two folds.

[0025] 1, as shown in Fig. 8A, the first shape maintaining portion 86 and the second shape maintaining portion 87 of the connecting portion 85 are not parallel to each other, so a twist occurs between the first shape maintaining portion 86 and the second shape maintaining portion 87, and in turn a twist occurs between the first upright portion 82 connected to the first shape maintaining portion 86 and the second upright portion 84 connected to the second shape maintaining portion 87. However, this twist is absorbed by the bending of the bent portion 88 of the connecting portion 85, and the magnetic sensor 76 and the circuit board 75 are reliably connected by the flexible wiring board 80.

[0026] 1, the first upright portion 82, the shape maintaining portions 86 and 87 of the connecting portion 85, and the second upright portion 84 maintain their shapes, while the bent portion 88 of the connecting portion 85 bends, resulting in a change to the state shown in FIG. 8C via the state shown in FIG. 8B. In this way, the rotation of the drive shaft 20 causes a twist between the first shape maintaining portion 86 and the second shape maintaining portion 87 of the connecting portion 85, which in turn causes a twist between the first upright portion 82 connected to the first shape maintaining portion 86 and the second upright portion 84 connected to the second shape maintaining portion 87. However, this twist is absorbed by the bent portion 88 of the connecting portion 85, and therefore the magnetic sensor 76 and the circuit board 75 can be reliably connected by the flexible wiring board 80.

[0027] In this way, by using a flexible wiring board 80 having a connecting portion 85 that can absorb the twisting that occurs as the drive shaft 20 rotates, it is possible to reliably connect the magnetic sensor 76 to the circuit board 75 placed on the base plate 4, so that the rotation of the drive shaft 20 can be detected with high accuracy by the magnetic sensor 76 placed at the center of rotation of the end of the rotating drive shaft 20, and the rotation of the drive shaft 20 can be controlled with high accuracy.

[0028] In the above-described embodiment, the electromagnetic drive unit 25 is used as the first drive unit that rotates the drive shaft 20, but the first drive unit that rotates the drive shaft 20 is not limited to this, and for example, a spring that applies force in the direction in which the drive shaft 20 rotates can also be used as the first drive unit.

[0029] Furthermore, in the vibration unit 30 described above, the second drive unit that moves the movable part 32 uses the electromagnetic coil 40 attached to the cover 31 and the magnet 66 attached to the movable part 32, but the second drive unit is not limited to such an electromagnetic drive unit and may be a unit that mechanically moves the movable part 32. Furthermore, in the above embodiment, the electromagnetic coil 40 is attached to the cover 31 and the magnet 66 is attached to the movable part 32, but the electromagnetic coil 40 may be attached to the movable part 32 and the magnet 66 may be attached to the cover 31. Furthermore, in the above example, the movable part 32 is moved in the Y direction, but the direction in which the second drive unit moves the movable part 32 is not limited to this and the movable part 32 can be moved in any direction.

[0030] Furthermore, in the above example, control unit 42 energizes electromagnetic coil 40 of vibration unit 30 before driving electromagnetic drive unit 25, but the timing at which control unit 42 energizes electromagnetic coil 40 of vibration unit 30 is not limited to this. For example, even after control unit 42 has driven electromagnetic drive unit 25, as long as there is no effect on shutter operation, control unit 42 may energize electromagnetic coil 40 of vibration unit 30 to cause vibration to drive shaft 20 before blade 5 enters opening 2.

[0031] In the above-described embodiment, since the magnetic sensor 76 has four terminals, the flexible wiring board 80 includes four first standing portions 82, connecting portions 85, second standing portions 84, and second connecting portions 83, but the numbers of the first standing portions 82, connecting portions 85, second standing portions 84, and second connecting portions 83 may vary depending on the number of terminals of the magnetic sensor 76.

[0032] Furthermore, although the above-described sensor unit 70 uses the magnetic sensor 76 as the sensor connected to the flexible wiring board 80, the sensor connected to the flexible wiring board 80 is not limited to a magnetic sensor. For example, a photointerrupter or a photoreflector can also be connected to the flexible wiring board 80.

[0033] In the above-described embodiment, the drive shaft 20 integrated with the drive lever 21 is configured to rotate, but the drive lever 21 and the drive shaft 20 may be separated, the drive shaft 20 may be fixed to the base plate 3, and the drive lever 21 may rotate relative to the drive shaft 20. In this case, the vibration unit 30 is configured to apply vibration to the drive lever 21, the magnet 74 of the sensor unit 70 is attached to the drive lever 21, and the magnetic sensor 76 is fixed to the base plate 4.

[0034] Although the preferred embodiments of the present invention have been described above, it goes without saying that the present invention is not limited to the above-described embodiments and may be embodied in various different forms within the scope of the technical concept thereof. [Explanation of symbols]

[0035] 1 shutter 2 aperture 3 Main plate (fixed part) 4 Base plate (fixed part) 10 Rotational drive unit 20 Drive shaft 25 Electromagnetic drive unit (first drive unit) 30 vibration unit 31 Cover 32 Moving parts 40 electromagnetic coil (second drive unit) 42 Control Unit 63 Contact area 66 Magnet (second drive unit) 70 Sensor Unit 74 Magnet 75 Circuit Board 76 Magnetic Sensor (Sensor) 80 Flexible wiring board 81 First connection 82 First Standing Section 83 Second Connection 84 Second Standing Section 85 Connecting part 86 First shape maintaining section 87 Second shape maintaining section 88 Refraction

Claims

1. A fixed portion; a drive shaft rotatable relative to the fixed portion; a first drive unit that rotates the drive shaft; A vibration unit that applies vibration to the drive shaft, a movable part having a contact part that can come into contact with the drive shaft and that is movable relative to the fixed part; a second drive unit that moves the movable unit to repeatedly bring the contact unit into contact with the drive shaft and out of contact with the drive shaft; a vibration unit including A rotary drive device comprising:

2. the vibration unit further includes a cover attached to the fixed portion, The movable portion is disposed between the fixed portion and the cover. The rotary drive device according to claim 1 .

3. The second drive unit includes: an electromagnetic coil attached to the cover; a magnet disposed on the movable part at a position adjacent to the electromagnetic coil; Including, The rotary drive device according to claim 2 .

4. The rotary drive device according to claim 1 , further comprising a control unit that drives the second drive unit of the vibration unit before rotating the drive shaft with the first drive unit.

5. A fixed portion; a drive shaft rotatable relative to the fixed portion; a drive unit that rotates the drive shaft; a sensor disposed at an end of the drive shaft; a circuit board disposed on the fixing portion; a flexible wiring board connecting the sensor and the circuit board, a first connection portion connected to the sensor; a first upstanding portion extending from the first connection portion in the axial direction of the drive shaft beyond the circuit board; a second connection portion connected to the circuit board; a second upright portion extending in the axial direction from the second connection portion; a connecting portion that connects the first upright portion and the second upright portion, the connecting portion absorbing twisting that occurs between the first upright portion and the second upright portion as the drive shaft rotates; A flexible wiring substrate including A rotary drive device comprising:

6. The connecting portion of the flexible wiring board is a first shape maintaining portion connected to the first upstanding portion and configured to maintain a shape during rotation of the drive shaft; a second shape maintaining portion connected to the second upright portion and configured to maintain a shape during rotation of the drive shaft; a bending portion that bends between the first shape maintaining portion and the second shape maintaining portion as the drive shaft rotates; Including, The rotary drive device according to claim 5 .

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