JPH08126288A - Actuator - Google Patents

Abstract

PURPOSE: To provide an actuator in which the driving of utilizing the feature of the operation of motor is selectively conducted by forming a drive motor of a stepping motor and a DC motor, and switchably operating the respective motors. CONSTITUTION: A driver 21 having a rotary shaft 10, a rotor 12, a stator 16, a coil 18 is provided at a drive motor 6. An intermittent part 25 having a commutator 22 provided at the rotary shaft 10 and a brush intermittently connected to the commutator 22 is provided. A stepping motor is formed of the driver 21, and a DC motor is formed of the driver 21 and the part 25. When the actuator is driven by the stepping motor, the driver 21 is repeatedly energized and interrupted to be stepwisely rotated. When it is driven by the DC motor, the driver 21 is energized and interrupted repeatedly by the interruption of the part 25 upon rotating, and continuously rotated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an actuator for rotating a rotary shaft to output power by inputting an electric current from the outside, and more particularly to an actuator suitable for a driving source for moving a lens of a camera.

[0002]

2. Description of the Related Art In recent years, cameras equipped with an autofocus device and a variable focus lens device (zoom device) have become widespread so that anyone can easily take pictures with the camera. These devices are composed of a focus lens and a zoom lens that are moved along the optical axis, a motor that moves these lenses, and the like.

Since the focus lens requires accuracy of the moving position rather than moving speed, a stepping motor is used as the moving motor. Further, since the zoom lens requires a moving speed rather than a moving position accuracy, a DC motor is used as a moving motor.

By the way, there is known a device for detecting the position of the focus lens and the position of the zoom lens and calculating the distance from these positions to the object, and there is a demand for mounting this device on a camera. Is increasing.
Therefore, in order to improve the accuracy of the calculation of the subject distance, it is necessary to detect the position of each lens as accurately as possible. Therefore, the position of the focus lens is calculated from the rotation speed of the stepping motor, and the position of the zoom lens is detected by a position detecting device such as a potentiometer, which is the actual position moved by the DC motor.

[0005]

However, in the structure in which the position of each lens is detected by the above-mentioned means to calculate the object distance, the position of the zoom lens is detected by the potentiometer or the like, so that highly accurate detection is possible. It becomes difficult to carry out, and an error may occur in the calculated subject distance.

On the other hand, in the structure in which the zoom lens is moved by the stepping motor, the moving speed of the zoom lens may decrease, and the quickness of the zoom operation may deteriorate.

Therefore, an object of the present invention is to provide an actuator suitable for a lens moving device which can perform almost accurate positioning without reducing the lens moving speed.

[0008]

In order to achieve the above-mentioned object, an actuator according to the present invention is an actuator for rotating a rotating shaft by an electric current from the outside.
A stepping motor unit and a DC motor unit are provided, and the operation of these stepping motor unit and the operation of the DC motor unit are switchable.

Specifically, in an actuator for rotating a rotating shaft by an electric current from the outside, a rotor fitted to the rotating shaft, a stator portion arranged around the rotor, and a stator portion A coil part provided, and by energizing a part of the coil part, a part of the stator part attracts a part of the rotor, and the rotor and the rotating shaft rotate, and the stator part A drive unit that stops the rotation when a part of the rotor is closest to the rotor, a rotating member fitted to the rotating shaft, and a conductive material provided in a part of the rotating member. A commutator; and a brush portion made of a conductive material that is in contact with the commutator, and an interrupting portion that connects and disconnects the commutator and the brush portion by rotation of the rotating shaft. The drive unit, the DC motor unit When the operation of the stepping motor section is selected by the drive section and the intermittent section, one part of the coil section is energized to rotate the rotor by an appropriate angle with respect to the stator section. When the coil is stopped, one part of the coil part is cut off to energize the other part, the rotor is turned by an appropriate angle to stop, and the turning shaft is turned to an appropriate angle by repeating the energization and the power failure. When the operation of the DC motor unit is selected by operating the stepping motor which is rotated for each coil, the coil unit and the brush unit are connected to each other by connecting and disconnecting the commutator and the brush unit to the coil unit. Is energized and a power failure is performed, one part of the coil portion is energized to rotate the rotor with respect to the stator portion, and this rotation switches the connection and disconnection between the commutator and the brush portion, One of the parts of the DC power supply is turned off, the other part is energized to rotate the rotor, and the DC motor is operated to rotate the rotating shaft continuously by repeating the energization and the power failure. It has a feature.

Further, it is characterized in that the drive section is a three-phase or five-phase unipolar drive stepping motor.

Further, the rotating shaft is linked to a lens moving device of the camera, and the lens is moved by the operation of the stepping motor and the operation of the DC motor.

[0012]

When the actuator is linked to the moving device for the zoom lens and the focus lens of the camera, and one of the lenses is moved by the switching device, the photographer operates the zoom switch. The movement of the zoom lens is selected, and the actuator is energized. At this time, the CPU selects the operation of the DC motor section of the actuator, and the actuator is driven by the operation of the DC motor.

That is, one part of the coil part of the drive part is energized, and a part of the rotor is attracted and rotated with respect to a part of the stator part. By this rotation, the connection between the commutator and the brush portion of the connecting / disconnecting portion is switched, the power of one portion of the coil portion is interrupted, the other portion is energized, and the rotor is rotated. Therefore, the energization and the power failure are repeated by the connecting / disconnecting portion with the rotation of the rotating shaft, whereby the rotating shaft is continuously rotated.

The zoom lens is rapidly moved by the operation of the DC motor of the actuator, and when the predetermined focal length is reached, the photographer finishes the operation of the zoom switch. Then, the CPU selects the operation of the stepping motor portion of the actuator, and the actuator is driven by the operation of the stepping motor.

That is, one portion of the coil portion is energized, and the rotor is rotated by an appropriate angle with respect to the stator portion and stopped. Then, one portion of the coil portion is cut off and the other portion is energized, and the rotor is rotated by an appropriate angle and stopped. Therefore, by repeating this energization and power failure, the rotating shaft is rotated stepwise at appropriate angles.

By the operation of the stepping motor of the actuator, the zoom lens is moved while measuring the number of rotations of the rotary shaft. Therefore, when the movement of the zoom lens is stopped, the movement position of the zoom lens is calculated almost accurately.

On the other hand, when the photographer depresses the release button, the switching device selects the movement of the focus lens. Then, the operation of the actuator is switched to the operation of the stepping motor by the CPU. As a result, the actuator is operated and the focus lens is moved through the same process as described above. Then, the moving position of the focus lens is grasped almost accurately.

Therefore, since the positions of the zoom lens and the focus lens are grasped almost accurately, the distance from these positions to the object can be calculated with high accuracy.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The actuator according to the present invention will be specifically described below based on the illustrated embodiments. In this embodiment, the case where the above actuator is used in the lens moving device that moves the focus lens and the zoom lens of the camera is described.

As shown in FIG. 2, the photographing optical system 1 of the camera
Is provided with a focus lens 2 and a zoom lens 4, and these lenses 2 and 4 are movable along the optical axis S. A drive motor 6 is linked to each of the lens frames 2a and 4a of the lenses 2 and 4 as an actuator through an appropriate lens moving device (not shown). Here, the lens moving device has switching means such as an appropriate clutch, and has a structure in which the linkage of the drive motor 6 to each of the lenses 2 and 4 can be switched. That is, the power of the drive motor 6 is transmitted to the zoom lens 4 when performing the zoom operation, and is transmitted to the focus lens 2 when performing the focusing operation.

As shown in FIG. 1, the drive motor 6 has a rotating shaft 10 penetrating substantially the center of the motor case 8 and a rotor 12 fitted to the rotating shaft 10. And the rotating plate 14 and the stator 16 provided around the rotor 12.
And a coil 18 and the like.

The rotating shaft 10 is rotatably supported by a bearing (not shown), and one end of the rotating shaft 10 is pressed against one side by a shaft holder 20. The rotor 12 fitted to the rotating shaft 10 is composed of an appropriate number of blade plates 12a radially extended along the axial direction as shown in FIGS. 1 and 5 (a). The blade plate 12a is made of an appropriate metal.

A stator 16 is provided around the rotor 12.
The stator 16 is provided with an appropriate number of blade plates 16 extending along the rotating shaft 10 by orienting the rotating shaft 10.
a is formed. In this embodiment, since the operation of the stepping motor of the drive motor 6 is a three-phase unipolar drive, the blade plates 12a of the rotor 12 are provided at intervals of about 45 degrees, and the blade plates 16a of the stator 16 are set at about 30 degrees. It is provided at intervals. However, these angles may be other suitable angles, for example, a five-phase drive structure may be used.

A conductive wire is wound around each vane plate 16a of the stator 16 to form a coil 18. One end of each coil 18 is provided as a terminal outside the motor case 8, and the other end is Connected to the coil 18 of. For example, as shown in FIG. 5A, in the structure in which the blade plates 16a are provided every 30 degrees, the coil 1 of the blade plates 16a separated by 90 degrees is used.
8 is connected.

The rotor 12, the stator 16 and the coil 18 described above constitute a drive unit 21.

On the other hand, as shown in FIG. 1, a rotary plate 14 as a rotary member made of an insulator is fitted to a part of the rotary shaft 10, and the outer peripheral surface of the rotary plate 14 is made of a conductive material. The commutator 22
Is attached. The commutator 22 has a conductive brush.
The brush 24 is fixed to the motor case 8 and its terminals are provided outside the motor case 8. Further, the rotating plate 14, the commutator 22, and the brush 24 constitute an interrupting portion 25.

Further, the driving section 21 constitutes a stepping motor section, and the driving section 21 and the interrupting section 25 are arranged.
A direct current motor section is constituted by and.

As shown in FIG. 5 (a), a plurality of commutators 22 are provided with an appropriate interval, and the commutators 22 with an interval of about 180 degrees are electrically connected to each other. Has been done. A plurality of brushes 24 are also provided at appropriate intervals. Therefore, when the appropriate brush 24 is in contact with the commutator 22, the brush 24 and the brush 24 spaced by about 180 degrees are in conduction.

Further, one terminal of the appropriate coil 18 of the stator 16 is A1 and the other terminal is a1. And the coil
One terminal of the coil 18 facing the coil 18 is A2 and the other terminal is a2. Further, the terminals a1 and a2 are respectively connected to the terminals of the brush 24 which are spaced apart by about 180 degrees.

Further, as shown in FIG. 3, the terminals a1 and a2 are
Are connected to the emitter terminal and the collector terminal of the switching transistor 26. Then, one terminal A1 of the coil 18
Is connected to the collector terminals of the DC motor transistor 28 and the stepping motor transistor 30, and the emitter terminal of the DC motor transistor 28 is connected to the first output terminal 32a of the DC motor drive 32 and the stepping motor transistor 30. The emitter terminals of are respectively connected to the first output terminals 34a of the stepping motor drive 34. The other terminal A2 of the coil 18 is connected to the collector terminals of the DC motor transistor 28 and the ground transistor 36, and the emitter terminal of the DC motor transistor 28 is the second output terminal 32 of the DC motor drive 32.
The ground terminal 36 has an emitter terminal grounded to the motor case 8 and the like.

Further, as shown in FIG. 5B, the terminals of the other coil 18 of the stator 16 are B1 and b1, and the terminals of the coil 18 facing the coil 18 are B2 and b2. And the terminals b1 and b2 are brushes 24
3 and is connected to the emitter terminal and collector terminal of the switching transistor 26 as shown in FIG. The terminal B1 is connected to the DC motor transistor 28
Is connected to the collector terminals of the stepping motor transistor 30 and the emitter terminal of the DC motor transistor 28 is the first output terminal 32 of the DC motor drive 32.
The emitter terminal of the stepping motor transistor 30 is connected to the second output terminal 34b of the stepping motor drive 34. And the coil
The other terminal B2 of 18 is connected to the terminal A2.

As shown in FIG. 5 (c), the terminals of the other coil 18 of the stator 16 are C1 and c1, and the terminals of the coil 18 facing the coil 18 are C2 and c2. And, the terminals c1 and c2 are brushes with an interval of about 180 degrees.
It is connected to each terminal of 24 and is connected to the emitter terminal and the collector terminal of the switching transistor 26 as shown in FIG. The terminal C1 is a transistor for DC motor.
28 is connected to the collector terminals of the stepping motor transistor 30 and the DC motor transistor 28.
The emitter terminal of is the first output terminal of the DC motor drive 32
The emitter terminal of the stepping motor transistor 30 is connected to the second output terminal 34c of the stepping motor drive 34 at 32a. The other terminal C2 of the coil 18 is connected to the terminals A2 and B2.

On the other hand, the base terminal of the switching transistor 26, the base terminal of the stepping motor transistor 30 and the base terminal of the ground transistor 36 are
It is connected to the motor switching terminal 38. The motor switching terminal
The base terminal of the DC motor transistor 28 is connected to the inverter 38 via an inverter 40.

The input terminals of the motor switching terminal 38, the DC motor drive 32, and the stepping motor drive 34 are connected to a CPU (not shown), and the motor drive is switched or the rotation direction is controlled by a control signal from the CPU. , ON / OFF, etc. are controlled.

The operation of the actuator according to this embodiment constructed as described above will be described below.

When the photographer performs a zoom operation before taking a photograph, he or she operates the zoom switch. At this time, the switching means of the lens moving device is operated, and the power of the drive motor 6 is transmitted to the zoom lens 4. And
A switching signal for the drive motor 6 is transmitted from the CPU to the motor switching terminal 38, and the operation of the DC motor is selected.

That is, as shown in FIG. 3, an off signal is transmitted from the CPU to the motor switching terminal 38,
It is converted into an ON signal via 40, and the DC motor transistor 28 is turned ON. On the other hand, since an off signal is transmitted to the stepping motor transistor 30 and the switching transistor 26, each circuit is in a disconnected state.

As a result, as shown in FIG. 4, the drive motor 6 is in the state of the DC motor in which the DC motor drive 32 is connected to the brush 24 via the coil 18. In this state, a signal for driving the motor is input from the CPU to the DC motor drive 32, and the start and end of driving, the direction of rotation, etc. are controlled. Then, in response to a drive start signal, each output terminal 32 of the DC motor drive 32 is
DC current is transmitted from a and 32b.

As shown in FIG. 5A, among the brushes 24 having an interval of about 180 degrees, the brushes 24 contacting the commutator 22 are energized. Then, the coil 18 connected to the brush 24 is energized, and the vane plate 12a of the rotor 12 adjacent to the vane plate 16a on which the coil 18 is wound is attracted. As a result, the rotor 12 rotates, so that the rotor shown in FIG.
As shown in (b), the brushes 24 are de-energized, and the brushes 24 adjacent to the brushes 24 are energized. Then, the coil 18 connected to the brush 24 is energized, and the vane plate 12a of the rotor 12 adjacent to the vane plate 16a on which the coil 18 is wound is attracted. This causes the rotor 12 to rotate, and the brushes 24 adjacent to the brush 24 are energized as shown in FIG. 5C. That is, the commutator 22 rotates together with the rotating shaft 10, the brush 24 that is conducted changes sequentially, and the coil 18 that is energized also changes, whereby the rotor 12 is continuously rotated, and the drive motor 6 is driven. Is rotated by the operation of the DC motor.

When the operation of the zoom switch is completed, a signal for stopping the drive motor 6 is transmitted from the CPU, the output from the DC motor drive 32 is stopped, and the drive of the drive motor 6 is stopped. Subsequently, a switching signal for the drive motor 6 is transmitted from the CPU to the motor switching terminal 38, and the operation of the stepping motor is selected.

That is, as shown in FIG. 3, an ON signal is transmitted from the CPU to the motor switching terminal 38, and the stepping motor transistor 30 and the switching transistor 26 are turned on. On the other hand, the ON signal is converted into an OFF signal via the inverter 40, so that the DC motor transistor 28 is turned OFF.

As a result, as shown in FIG. 6, in the drive motor 6, the stepping motor drive 34 has the coil 18
The state of the stepping motor connected to is entered. In this state, the stepping motor drive from the CPU
Signals such as motor drive and rotation direction are input to 34. Then, by transmitting the drive signal, the pulse signals are sequentially transmitted from the output terminals 34a, 34b, 34c of the stepping motor drive 34.

For example, when transmission is performed from the first output terminal 34a, the coil 18 connected to the first output terminal 34a is energized, and as shown in FIG.
The blade plate 12a of the rotor 12 that is close to the winding blade plate 16a is attracted, and is stopped in the closest state. Then, when the transmission from the second output terminal 34b is performed, the coil 18 connected to the second output terminal 34b is energized, and the coil 18 is wound as shown in FIG. 7B. The vane plate 12a of the rotor 12 that is close to the vane plate 16a is attracted and stopped in the closest state. Then, when transmission is performed from the third output terminal 34c, as shown in FIG. 7C, the blades of the rotor 12 close to the blade plate 16a around which the coil 18 connected to the third output terminal 34c is wound. The plate 12a is stopped in the closest position. That is, the coil to be energized
18, the rotor 12 is rotated stepwise by the coil 18, and the drive motor 6 is rotated by the operation of the stepping motor.

Then, after turning by an appropriate number of steps and then stopping, the movement of the zoom lens 4 is stopped.

On the other hand, when the focusing operation is performed, the switching means of the lens moving device is actuated so that the power of the drive motor 6 is transmitted to the focus lens 2. When the focus lens 2 is moved, an ON switching signal is transmitted from the CPU to the motor switching terminal 38, and the drive motor 6 is driven by the operation of the stepping motor.

Therefore, according to this embodiment, when the zoom lens 4 is moved, the drive motor 6 is driven by both the operation of the DC motor and the operation of the stepping motor. Therefore, since the focal length is set roughly by the operation of the DC motor, the operation of the zoom device is performed quickly and the operability is not deteriorated.

Since the final focal length is set by the operation of the stepping motor, the zoom lens 4 can be positioned almost accurately. On the other hand, since the focus lens 2 is moved by the operation of the stepping motor, the position of the focus lens 2 can be grasped almost accurately. Therefore, the distance to the subject can be calculated extremely accurately from the positions of the zoom lens 4 and the focus lens 2.

Further, according to the drive motor 6 of this embodiment, one drive motor 6 is driven by switching between the operation of the stepping motor and the operation of the DC motor, so that the drive which makes the best use of each characteristic is selected. can do.
For example, when the accuracy of the rotation angle or the like is prioritized over the magnitude of the rotation speed, the stepping motor is driven, and conversely, when the magnitude of the rotation speed is emphasized over the accuracy of the rotation angle or the like, the DC motor It can be driven by operation. Therefore, even when only one motor can be installed due to the installation space or the like, the operation of the stepping motor and the operation of the DC motor can be performed, and more appropriate control can be performed.

Moreover, the operation of the stepping motor and the operation of the DC motor can be switched simply by sending a signal to the motor switching terminal 38, and can be performed very easily.
Therefore, compared to a structure in which a stepping motor and a DC motor are provided and a transmission path is switched by a clutch or the like,
The number of parts can be reduced, and the transmission path is not changed, so that the transmission is surely performed. Further, the number of parts does not increase as compared with the structure including only one of the motors, the size of the product incorporating the drive motor 6 is not increased, and more appropriate control is performed. be able to.

In this embodiment, the zoom lens 4 and the focus lens 2 are moved by switching one drive motor 6, but the drive motor 6 is provided to move the zoom lens 4. For moving the focus lens 2, another stepping motor may be provided. According to this structure, the drive sources for the zoom lens 4 and the focus lens 2 are separate, so that the zoom operation and the focusing operation can be performed simultaneously. Also,
It is not necessary to provide a switching means such as a clutch, so that power transmission is surely performed.

Further, in this embodiment, the operation of the stepping motor of the drive motor 6 is the three-phase unipolar drive,
It may be five phases or the like. Therefore, an appropriate drive motor can be selected according to the needs of the product in which the drive motor 6 is incorporated.

[0052]

As described above, according to the actuator of the present invention, the stepping motor section and the DC motor section are provided, and the operation of each motor section can be switched. It is possible to select and perform the driving that makes full use of it. That is, when the accuracy of the rotation angle is prioritized over the rotation speed, it can be driven by the operation of the stepping motor, and conversely, when the rotation speed is more important than the accuracy of the rotation angle, it can be driven by the operation of the DC motor.

Therefore, even if the conventional structure is such that the stepping motor and the DC motor are separately provided and are switched and driven according to their respective characteristics, they can be driven by one actuator, and the size of the product can be reduced. Contributes to weight reduction. Further, even if the structure is conventionally driven by one motor, it is possible to drive with different motor characteristics by using the above actuator, and more appropriate control can be performed.

Further, the rotary shaft of the actuator is linked to the lens moving device of the camera, and the lens is moved by the operation of the stepping motor and the operation of the DC motor. For this reason, when the lens is moved by the operation of the DC motor, the lens is moved quickly, so that the zoom operation is not slowed down, for example. Further, when the lens is moved by the operation of the stepping motor, the position of the lens is detected almost accurately, so that a highly accurate result can be obtained when calculating the subject distance from the position of the focus lens and the zoom lens, for example. Obtainable.

[Brief description of drawings]

FIG. 1 is a partially omitted sectional view showing an embodiment of an actuator according to the present invention.

FIG. 2 is a schematic block diagram when the actuator according to the present invention is used for moving a lens of a camera.

FIG. 3 is a schematic circuit diagram for driving an actuator according to the present invention.

FIG. 4 is a partially omitted circuit diagram for driving the actuator according to the present invention by the operation of a DC motor.

FIG. 5 is a partially omitted cross-sectional view when the actuator according to the present invention is driven by the operation of a DC motor.

FIG. 6 is a partially omitted circuit diagram for driving the actuator according to the present invention by the operation of a stepping motor,
It corresponds to FIG.

7 is a partially omitted cross-sectional view when the actuator according to the present invention is driven by the operation of a stepping motor, and corresponds to FIG.

[Explanation of symbols]

 2 Focus lens 4 Zoom lens 6 Drive motor (actuator) 10 Rotation shaft 12 Rotor 14 Rotation plate (rotation member) 16 Stator 18 Coil 21 Drive part (stepping motor part, DC motor part) 22 Commutator 24 Brush 25 Intermittent Section (DC motor section) 32 DC motor drive 34 Stepping motor drive 38 Motor switching terminal

Claims (5)

[Claims] 1. An actuator for rotating a rotating shaft by an electric current from the outside, comprising a stepping motor section and a DC motor section, and the operation of these stepping motor section and the operation of the DC motor section can be switched freely. An actuator characterized by. 2. An actuator for rotating a rotating shaft by an electric current from the outside, wherein a rotor fitted to the rotating shaft, a stator portion arranged around the rotor, and a coil provided on the stator portion. And a part of the coil part is energized, the part of the stator part attracts part of the rotor, the rotor and the rotating shaft rotate, and part of the stator part A drive unit that stops the rotation when the rotor and a part of the rotor are closest to each other, a rotating member fitted to the rotating shaft, and a commutator made of a conductive material provided in a part of the rotating member. A brush portion made of a conductive material that is in contact with the commutator, and an interrupting portion that connects and disconnects the commutator and the brush portion by rotation of the rotation shaft, the stepping motor portion by the drive portion. The DC motor unit is When the operation of the stepping motor section is selected, the one part of the coil section is energized and the rotor is rotated by an appropriate angle with respect to the stator section and stopped. , One part of the coil is cut off and the other part is energized,
When the stepping motor that rotates the rotor by an appropriate angle to stop it and rotates the rotating shaft by an appropriate angle by repeating this energization and power failure is operated, and the operation of the DC motor section is selected Is to connect the coil portion and the brush portion, and to energize the coil portion and power failure by connecting and disconnecting the commutator and the brush portion, and energize one portion of the coil portion to drive the rotor. Rotating with respect to the stator portion, the rotation of the commutator and the brush portion is switched by this rotation, power is interrupted in one portion of the coil portion and the other portion is energized to rotate the rotor,
The actuator according to claim 1, wherein a DC motor for continuously rotating the rotating shaft is operated by repeating the energization and the power failure. 3. The actuator according to claim 2, wherein the drive unit is a three-phase unipolar drive stepping motor. 4. The actuator according to claim 2, wherein the drive unit is a 5-phase unipolar drive stepping motor. 5. The method according to claim 1, wherein the rotating shaft is linked to a lens moving device of a camera, and the lens is moved by the operation of the stepping motor and the operation of the DC motor. 4. The actuator according to item 4.