A three-state micro-rotation positioning mechanism

Abstract

The present invention discloses a three-state micro-rotation positioning mechanism, including a housing, a motor, a shaft cylinder, and a load bracket. The housing is a cylindrical barrel-shaped structure with an opening at the top, a through hole at the center of the bottom, fixing ears on the left and right sides, and a wire outlet hole on the front side. The motor is a rotary motor with a stator inside an outer rotor, fixed inside a closed space inside the housing, and the rotation axis of the rotor coincides with the light-transmitting axis. The shaft cylinder is a hollow cylindrical structure, which is a part of the motor rotor. Threaded holes are designed around the top, and there are two limiting protrusions at the bottom. The load bracket is a flange-shaped structure, and screw holes are arranged on the surrounding raised parts. The present invention has the characteristics of small size, light weight, low power consumption, and fast switching, and can achieve state switching with lower power consumption in a smaller space.

Description

Technical Field

[0001] The invention belongs to the field of optoelectronic precision instruments and machinery, and in particular relates to a three-state micro-rotation positioning mechanism for switching optical path states. Background Art

[0002] With the development of science and technology and the needs of national defense, the amount of information that aircraft or ground vehicles need to transmit to the outside world is increasing, and the transmission speed requirements are getting faster and faster. Wireless laser communication technology with stronger confidentiality, faster speed and better anti-interference performance is increasingly being applied to the communication of mobile vehicles. Inside the wireless laser communication equipment, various optical devices such as lasers, wave plates, filters, polarizers or reflectors are required to realize the manipulation and regulation of light. Some of the links require the rotation of optical devices according to needs, so a rotation positioning mechanism is needed. For vehicles, the internal space layout is relatively compact and the load capacity is limited, especially for aircraft and spacecraft. Therefore, the rotation positioning mechanism used needs to have a smaller size, mass and power consumption. At present, the existing rotation positioning mechanism mostly uses a stepper motor to drive a turntable or a brushless motor to drive directly, which is not only large in mass, large in size, high in power consumption, but also high in cost. When the stepper motor rotates, it will generate vibration, affecting the accuracy of the laser equipment. In order to ensure the rotation accuracy, the existing motor drive usually rotates slowly, resulting in a long working interruption cycle of the laser communication equipment. Therefore, it is necessary to design a three-state micro-rotational positioning mechanism to help the devices in laser communication equipment to switch between three positions between two end limits and a middle position. Summary of the invention

[0003] To solve the above technical problems, the present invention provides a three-state micro rotary positioning mechanism, which miniaturizes the rotary positioning mechanism so that the rotary positioning mechanism can achieve low mass, small volume, low power consumption and high speed, and realizes switching between three states between two end limits and a middle position.

[0004] In order to achieve the above object, the present invention adopts the following technical scheme:

[0005] A three-state micro-rotation positioning mechanism comprises a housing, an end cover and a motor; the stator of the motor is composed of an O-shaped iron core, a left coil and a right coil. The O-shaped iron core is composed of a left pole shoe, a right pole shoe, an upper pole shoe and a lower pole shoe, and the connection between the left pole shoe, the right pole shoe and the outer ring of the O-shaped iron core is wound with a left coil and a right coil. The outer edge of the O-shaped iron core is connected to the inner side of the housing by a circumferential fit. The rotor of the motor is composed of a shaft cylinder, a load bracket, a permanent magnet, a spacer, a bearing, a special screw ring and a target magnet. The load bracket is above the shaft cylinder and is connected by screws. From the middle to the bottom of the shaft cylinder, the permanent magnet, the spacer, the bearing and the special screw ring are inserted from top to bottom through the shaft hole. The special screw ring is matched with the thread at the bottom of the shaft cylinder, and the permanent magnet, the spacer and the bearing are pressed on the shaft cylinder by the thread. The target magnet is glued into the pit on the special screw ring. The bearing is embedded in the bearing seat at the bottom of the inner side of the housing by the shaft hole match, and is pressed by the bearing pressing sheet through the screw. The end cover is fixedly connected to the shell through screw holes on the left and right sides. The left position detection device and the right position detection device are bonded in the groove at the bottom of the outer side of the shell.

[0006] Preferably, the height of the shell is within 10-20 mm (including the boundary); the outer diameter of the cylindrical part of the shell is within 10-25 mm (including the boundary).

[0007] Preferably, the bottom center of the shell has a through hole, and the hole shape is a circle and two sectors are additionally cut out of the circle. The two limit latches at the bottom of the shaft cylinder will rotate within the sector area, and the rotation range of the shaft cylinder is within the range of 60°~120°.

[0008] Preferably, the air gap distance between the permanent magnet and the left pole shoe, the right pole shoe, the upper pole shoe, and the lower pole shoe of the O-shaped iron core is within 0.1-0.6 mm (including the boundary).

[0009] Preferably, the total mass of the three-state micro-rotational positioning mechanism is within 30g.

[0010] Preferably, the left position detection device and the right position detection device are not limited to Hall elements, but also include all sensors such as eddy current sensors that can detect aluminum partition plates.

[0011] Preferably, the load bracket is not limited to the form shown in the drawings of the present invention, but also includes all load brackets such as mirror holders, laser holders, etc. that can match the shaft tube.

[0012] Compared with other existing rotation positioning mechanisms, the present invention has the following beneficial effects:

[0013] 1. Small size. The outer diameter of the present invention is within the range of 10-25 mm, and the total height is within the range of 10-20 mm. The size is significantly smaller than the existing rotary positioning mechanism driven by stepping motors, brushless motors, etc., which greatly saves space.

[0014] 2. Lightweight: The weight of the present invention is less than 30g, which is significantly smaller than the existing rotary positioning mechanism. Compared with the existing mechanism, it is more suitable for use in aircraft and reduces the load mass.

[0015] 3. Easy to drive. The left coil and the right coil in the motor of the present invention are in series connection, and the actuation of the present invention can be realized by applying a voltage or current pulse of a fixed value. Compared with servo motors, stepper motors or brushless motors, it saves the volume and mass of the larger drive controller and does not require complex PWM signals.

[0016] 4. Low power consumption. The motor of the present invention is a Maxwell force motor. Instantaneous current is applied to the left and right coils to drive the permanent magnet to rotate. When the rotor is at the end positions on both sides, the rotor will rotate toward the middle position due to repulsion after power is turned on; when the rotor is in the middle position, the rotor will rotate toward one end position due to attraction after power is turned on. When driving, only a pulse current of less than 50ms is required to drive the mechanism to switch from the current position to the next position. The instantaneous power during driving is less than 10W, and the power consumption of one drive is less than 0.5J, which effectively saves energy on the mobile vehicle.

[0017] 5. Fast switching speed. The permanent magnet in the motor of the present invention is a neodymium iron boron magnet, which can maintain a strong magnetic field and generate a large torque under a small excitation current. The switching time from one end limit to the other end limit of the present invention is within 0.1s. It can avoid the situation where the switching time of other existing solutions is too long, affecting the continuous operation of laser communication equipment.

[0018] 6. High positioning accuracy. In the present invention, the three limit positions of the shaft cylinder are 0°, 45°, and 90°, of which 0° and 90° are the two end limits, and 45° is the middle position. The two end limits are mechanical limits, which are positioned by the tenon at the bottom of the shaft cylinder stuck in the groove end face of the bottom hole of the shell, with high accuracy. The middle limit is a magnetic limit, which is positioned by the attraction between the permanent magnet and the upper and lower pole shoes, and the error can be limited to ±0.5°.

[0019] 7. It has the function of self-locking when power is off. The present invention can realize self-locking when power is off at three positions. When disturbed, it can automatically return to the original position within a certain angle range by relying on the magnetic force of the permanent magnet, which can effectively prevent the vibration of the carrier from changing the state of the rotation positioning mechanism.

[0020] 8. Long service life. The coils in the motor of the present invention are in a state of no current flowing through them for most of the time, which makes the present invention have a long electrical life. The motor rotor is driven by a deep groove ball bearing during rotation, and there is almost no friction, which makes the present invention have a long mechanical life. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1It is an axonometric view of a three-state micro-rotation positioning mechanism of the present invention;

[0022] Figure 2 It is a top view of a three-state micro-rotation positioning mechanism of the present invention;

[0023] Figure 3 It is a bottom view of a three-state micro-rotation positioning mechanism of the present invention;

[0024] Figure 4 is a top view of the motor of the present invention;

[0025] Figure 5 It is a front cross-sectional view of a three-state micro-rotation positioning mechanism of the present invention;

[0026] Figure 6 It is a left side view and a front view of the special screw ring of the present invention;

[0027] Among them, 1: shell; 1a: through hole; 2: end cover; 3: load bracket; 4: shaft cylinder; 5a: left position detection device; 5b: right position detection device; 6: permanent magnet; 7: O-shaped iron core; 7a: left pole shoe; 7b: right pole shoe; 7c1: upper pole shoe 7c2: lower pole shoe; 8a: left coil; 8b: right coil; 9: spacer; 10: bearing; 11: bearing pressure plate; 12: special screw ring; 13: target magnet; 14: motor. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0029] like Figure 1-Figure 6 As shown, a three-state micro-rotation positioning mechanism of the present invention comprises a housing 1, an end cover 2, and a motor 14. The end cover 2 is located on the top of the housing 1, and the end cover 2 and the housing 1 are fixedly connected by screws in screw holes on the left and right sides, and the motor 14 is enclosed in a closed space formed by the housing 1 and the end cover 2.

[0030] The stator of the motor 14 is composed of an O-shaped iron core 7, a left coil 8a, and a right coil 8b. The O-shaped iron core 7 is composed of a left pole shoe 7a, a right pole shoe 7b, an upper pole shoe 7c1, and a lower pole shoe 7c2. The bent plate-shaped pole shoes located on the left and right sides are the left pole shoe 7a and the right pole shoe 7b, and the block-shaped pole shoes located on the upper and lower sides are the upper pole shoe 7c1 and the lower pole shoe 7c2. The connection between the left pole shoe 7a, the right pole shoe 7b and the outer ring of the O-shaped iron core 7 is wound with the left coil 8a and the right coil 8b. The outer edge of the O-shaped iron core 7 is connected to the inner side of the housing 1 in a circumferential fit.

[0031] The rotor of the motor 14 is composed of a shaft cylinder 4, a load bracket 3, a permanent magnet 6, a spacer 9, a bearing 10, a special screw ring 12, and a target magnet 13. The load bracket 3 is above the shaft cylinder 4 and connected by screws. From the middle to the bottom of the outer side of the shaft cylinder 4, the permanent magnet 6, the spacer 9, the bearing 10 and the special screw ring 12 are inserted from top to bottom through the shaft hole. The inner wall of the special screw ring 12 is tapped with a right thread, and 12 target magnet holes are evenly punched on the ring. The special screw ring 12 is matched with the thread at the bottom of the shaft cylinder 4, and the permanent magnet 6, the spacer 9, and the bearing 10 are pressed on the shaft cylinder 4 by the thread. The target magnet 13 is glued to the target magnet hole on the special screw ring 12. The bearing 10 is embedded in the bearing seat at the bottom of the inner side of the housing 1 by means of the shaft hole, and is pressed by the bearing pressing sheet 11 through screws. The left position detection device 5a and the right position detection device 5b are bonded to the groove at the bottom of the outer side of the housing 1.

[0032] Preferably, the front side of the special screw ring 12 includes 12 evenly distributed blind holes for installing the target magnet, and the back side of the screw ring is designed with an annular protrusion, such as Figure 6 shown.

[0033] Preferably, the height of the housing 1 is between 10 and 20 mm, and the outer diameter of the cylindrical portion is between 10 and 25 mm. The housing is relatively small in size, which can save space inside the laser device and reduce the size of the device.

[0034] Preferably, the bottom of the shell 1 has a through hole 1a, and the hole type is circular with two additional sectors cut out of the outside. The two limiting latches at the bottom of the shaft cylinder 4 will rotate within the sector area, and the rotation range of the shaft cylinder 4 is 60°~120°. The aperture of the through hole 1a at the bottom of the shell 1 can be made into different sizes within 10 mm according to the outer diameter of the shell 1, allowing lasers with a diameter of less than 10 mm to pass through. The two sector areas around the through hole 1a at the bottom of the shell 1 are latch grooves, and the two side end faces of each sector area are limiting surfaces, which are used to limit the latch at the bottom of the shaft cylinder 4, and are also the self-locking position of the latch. Different sector center angles can be selected according to actual needs to determine the rotation range of the shaft cylinder 4.

[0035] Preferably, the air gap distance between the permanent magnet 6 and the left pole shoe 7a, the right pole shoe 7b, the upper pole shoe 7c1, and the lower pole shoe 7c2 of the O-shaped iron core 7 is 0.1-0.6 mm. The air gap distance between the permanent magnet 6 and the four pole shoes determines the self-locking force and the driving force, and can be designed according to different usage needs. The air gap between the upper pole shoe 7c1, the lower pole shoe 7c2 and the permanent magnet 6 determines whether the rotation positioning mechanism has a third state, i.e., an intermediate state. Increasing the size of the air gap can convert the three-state micro-rotation positioning mechanism into a two-state use.

[0036] The total mass of the invention is within 30g. The mass is small, which reduces the total mass of the laser equipment and lightens the load of the carrier.

[0037] Preferably, the implementation of the position detection function of the present invention includes but is not limited to the left position detection device 5a and the right position detection device 5b, and can also be any sensor that can detect aluminum materials.

[0038] Preferably, the load bracket 3 of the present invention includes but is not limited to the forms shown in the drawings, and any mirror frame that can be embedded in the shaft tube 4 and matched with three screw holes can be called a load bracket 3.

[0039] The working principle of the present invention is: the three-state micro-rotation positioning mechanism has three states when the power is off and stationary, that is, the motor rotor is self-locked at the 0° position, 45° position, and 90° position. The principle of self-locking when the power is off is the mutual attraction between the permanent magnet 6 and the pole shoes of the O-shaped iron core 7. Figure 4 In the figure, when the motor rotor is at the 0° position, the upper left of the permanent magnet 6 is the N pole, and the lower right is the S pole; when the motor rotor is at the 45° position, the upper part of the permanent magnet 6 is the N pole, and the lower part is the S pole; when the motor rotor is at the 90° position, the upper right of the permanent magnet 6 is the N pole, and the lower left is the S pole. The magnetic field pointing range is between 45° in the upper left and 45° in the upper right. When the three-state micro-rotary positioning mechanism is self-locking at 0° or 90°, the magnetic poles of the permanent magnet 6 attract each other with the left pole shoe 7a and the right pole shoe 7b, generating a self-locking torque. There is a limit tenon at the bottom of the shaft cylinder 4 in the rotor, which is pressed to the end face of the tenon groove at the bottom of the housing 1 under the action of the self-locking force to form a self-locking. If there is a disturbance that causes the rotor to leave the self-locking position, the rotor will still be pulled back to the limit position by magnetic force within a range of 20°. When the three-state micro-rotation positioning mechanism is self-locked at 45°, the magnetic poles of the permanent magnet 6 and the upper pole shoe 7c1 and the lower pole shoe 7c2 attract each other, and the magnetic stiffness of the magnetic field stabilizes the rotor at about 45°, and can resist ±10° disturbance and pull it back to the 45° position. This design has a large self-locking torque when self-locking, and has a high self-locking accuracy, which is better than the existing solution.

[0040] The left pole shoe 7a and the right pole shoe 7b of the O-shaped iron core 7 are respectively wound with a left coil 8a and a right coil 8b on the outside, and the two coils are in series and have the same excitation direction. When the motor is driven to rotate, if the motor rotor is at the 0° position or the 90° position at this time, after applying the current in the correct direction, the left pole shoe 7a and the right pole shoe 7b will become the two poles of the electromagnet formed by the O-shaped iron core 7, and these two poles and the poles near one end of the permanent magnet 6 are the same poles. The O-shaped iron core 7 is fixed on the shell 1 and cannot rotate, and the permanent magnet 6 is fixed on the shaft cylinder 4 to form a rotor, which rotates relative to the shell 1 through the bearing 10. After power is turned on, the permanent magnet 6 is subjected to the repulsive force of the same poles and drives the shaft cylinder 4 to rotate. If the power is turned off when it is about to reach the 45° position, the permanent magnet will be attracted by the upper pole shoe 7c1 and the lower pole shoe 7c2 at this time and stabilize at the 45° position. If the power is not turned off when the angle passes 45°, the motor rotor will maintain speed due to inertia and continue to rotate beyond the 45° position until it is attracted by the left pole shoe 7a and the right pole shoe 7b and reaches the other end limit. If the rotor is at 45° when stationary, when the two coils are energized, the directions of the magnetic fields generated by the permanent magnet 6 and the O-shaped iron core 7 are orthogonal. Under the action of the magnetic field, the permanent magnet 6 is more inclined to rotate to a position where the directions of the two magnetic fields are the same, and is attracted by the left pole shoe 7a and the right pole shoe 7b and fixed in the limit position. This actuation principle has the characteristics of high speed and low power consumption that cannot be matched by the current existing solutions.

[0041] When the three-state micro-rotation positioning mechanism is in operation, if a smaller current and a shorter pulse time are applied to the left pole shoe 7a and the right pole shoe 7b, the motor rotor will rotate 45°; if a larger current and a slightly longer pulse time are applied, the motor rotor can directly rotate 90°. The time for both switching is no more than 0.1s.

[0042] The detection of the state of the present invention is achieved by the left position detection device 5a, the right position detection device 5b adhered to the bottom of the housing 1, and the two target magnets 13 on the special screw ring 12. The special screw ring 12 is provided with 12 evenly distributed target magnet holes for placing the target magnets 13. During actual installation, only two holes 90° apart are selected to install the target magnets 13. When rotated to the 0° position, the left position detection device 5a can detect the target magnet 13, and when rotated to the 90° position, the right position detection device 5b can detect the target magnet 13. When rotated to the 45° position, neither the left position detection device 5a nor the right position detection device 5b can detect the target magnet 13.

[0043] Preferably, the left position detection device 5a and the right position detection device 5b are both 3144E Hall elements, which are S-pole unipolar Hall elements. The effective voltage is 0V, and the invalid voltage is the driving voltage. When the S pole of a magnet approaches, the signal end of the Hall element will change from the driving voltage to 0V. The driving voltage range of the position detection Hall is 4.5~24V, and the output signal is an analog voltage, which can be collected by an A / D device. The signal is relatively simple, does not require processing, and is more convenient to operate.

[0044] Preferably, the load bracket 3 is fixed to the shaft cylinder 4 by three screws, and the load can be disassembled and replaced at any time when the motor rotor is stationary. The load bracket 3 can be in the form of not only the horizontal mirror frame shown in the figure, but also a vertical mirror frame, a laser frame, etc., which can meet various load rotation requirements.

[0045] Preferably, except for the load bracket 3 and the left position detection device 5a and the right position detection device 5b, the other parts of the three-state micro-rotation positioning mechanism are wrapped inside by the outer shell 1 and the end cover 2, which has higher equipment safety and human-machine safety and is not easy to be damaged or hurt.

[0046] Preferably, the mounting surface of the three-state micro-rotation positioning mechanism is the bottom of the housing 1 , and is connected to the bottom plate of the device by means of fixing ears on the left and right sides of the housing 1 . Figure 1 The light input direction can be perpendicular to the mounting surface, or other forms of load brackets can be used to make the light input direction parallel to the mounting surface.

[0047] The 0° position, 45° position and 90° position described in this specification are Figure 1-Figure 5 The real physical meaning of the special case of the scheme is the initial position, the middle position and the end position. For example, for a three-state micro-rotation positioning mechanism with an angle of 120°, it is the 0° position, the 60° position and the 120° position.

[0048] The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in this field.

[0049] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments, or replace some of the technical features therein with equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A three-state micro-rotation positioning mechanism, characterized in that: The invention comprises a housing (1), an end cover (2) and a motor (14); the end cover (2) is located on the top of the housing (1) and is fixedly connected to the housing (1) through screw holes on the left and right sides; the motor (14) is enclosed in a closed space formed by the housing (1) and the end cover (2); the stator of the motor (14) comprises an O-shaped iron core (7), a left coil (8a), and a right coil (8b); the O-shaped iron core (7) is divided into a left pole shoe (7a), a right pole shoe (7b), an upper pole shoe (7c) and a lower pole shoe (7d). 1) and a lower pole shoe (7c2), wherein the bent plate-shaped pole shoes located on the left and right sides are the left pole shoe (7a) and the right pole shoe (7b), and the block-shaped pole shoes located on the upper and lower sides are the upper pole shoe (7c1) and the lower pole shoe (7c2); the left coil (8a) and the right coil (8b) are wound around the connection between the left pole shoe (7a), the right pole shoe (7b) and the outer ring of the O-shaped iron core (7); the outer edge of the O-shaped iron core (7) is connected to the inner side of the housing (1) in a circumferential manner; the rotor of the motor (14) is composed of The invention comprises a shaft cylinder (4), a load bracket (3), a permanent magnet (6), a spacer (9), a bearing (10), a special screw ring (12), and a target magnet (13); the load bracket (3) is located above the shaft cylinder (4) and connected by screws; from the middle to the bottom of the outer side of the shaft cylinder (4), the permanent magnet (6), the spacer (9), the bearing (10) and the special screw ring (12) are inserted through the shaft hole from top to bottom; the special screw ring (12) and the bottom of the shaft cylinder (4) are connected by screws. The threaded fitting is used to press the permanent magnet (6), the spacer (9) and the bearing (10) onto the shaft tube (4); the target magnet (13) is glued into the recess on the special screw ring (12); the bearing (10) is embedded into the bearing seat at the bottom of the inner side of the housing (1) by means of shaft hole fitting, and is pressed by a bearing pressing plate (11) through screws; the left position detection device (5a) and the right position detection device (5b) are glued into the groove at the bottom of the outer side of the housing (1).

2. A three-state micro-rotation positioning mechanism according to claim 1, characterized in that: The height dimension of the shell (1) is 10-20 mm; the outer diameter of the cylindrical part of the shell (1) is 10-25 mm.

3. A three-state micro-rotation positioning mechanism according to claim 1, characterized in that: The bottom of the housing (1) has a through hole (1a), the hole shape of which is circular with two additional sectors cut out of the outside. The two limit latches at the bottom of the shaft cylinder (4) rotate within the sector area, and the rotation range of the shaft cylinder (4) is 60° to 120°.

4. A three-state micro-rotation positioning mechanism according to claim 1, characterized in that: The air gap distance between the permanent magnet (6) and the left pole shoe (7a), the right pole shoe (7b), the upper pole shoe (7c1), and the lower pole shoe (7c2) of the O-shaped iron core (7) is 0.1-0.6 mm.

5. The three-state micro-rotation positioning mechanism according to claim 1, characterized in that: The total mass of the three-state micro-rotation positioning mechanism is within 30g.

6. A three-state micro-rotation positioning mechanism according to claim 1, characterized in that: The load support includes a mirror holder or a laser holder that can be matched with the shaft cylinder.

7. A three-state micro-rotation positioning mechanism according to claim 1, characterized in that: The left position detection device (5a) and the right position detection device (5b) are Hall elements or eddy current sensors.

8. The three-state micro-rotation positioning mechanism according to claim 1, characterized in that: The front side of the special screw ring is provided with 12 evenly distributed blind holes, and the back side is designed with an annular protrusion.

Images