A miniature linear position switching device

Abstract

The present invention discloses a miniature linear position switching device, which mainly includes a housing, a motor, and a load bracket. The stator of the motor is composed of main parts such as a housing, an end cover, a coil frame, a coil, a permanent magnet, and a spring, and the mover is composed of a moving shaft and a load bracket. The permanent magnet is located in a slot in the middle of the coil frame. The front and rear coils are respectively wound in the front and rear slots of the coil frame. The front and rear rear covers are respectively connected to the front and rear ends of the housing by screws, and the front and rear springs are sleeved on the outside of the bosses of the front and rear rear covers and fixedly connected thereto. The coil frame is located in a closed space formed by the housing, the front and rear rear covers. The front and rear shaft sections of the moving shaft match the center holes of the front and rear rear covers. 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 photoelectric precision instruments and machinery, and in particular relates to a miniature linear position switching device for switching optical path states. Background Art

[0002] With the rapid development of optical technology, researchers have higher and higher requirements for advanced optical precision instruments. In optical imaging research or laser communication research, it is often necessary to change the position of optical devices such as lenses, optical sensors, lasers, etc. during the operation of the equipment to achieve online manipulation and regulation of light. In some scenarios where the space is small or the load is limited, the position switching mechanism used is required to have a smaller size, mass and power consumption. Currently, most existing linear positioning mechanisms are directly driven by brushless linear motors, which are not only large in mass, volume, and power consumption, but also high in cost. Existing brushless motors or servo motors will vibrate when they rotate, affecting the accuracy of optical equipment, and in order to ensure positioning accuracy, they usually rotate slowly, resulting in a longer working interruption period of the optical equipment, affecting the continuity of optical experiments or the continuity of camera images. Therefore, it is necessary to design a miniature linear position switching device to help optical equipment achieve low-power and fast state switching. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides a miniature linear position switching device, which miniaturizes the linear positioning mechanism so that the linear positioning mechanism can achieve low mass, small volume, low power consumption and high speed, and realize state switching.

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

[0005] A miniature linear position switching device comprises a load bracket, a housing and a motor; the stator of the motor is composed of a housing, a front cover, a rear cover, a coil frame, a front coil, a rear coil, a permanent magnet, a short partition, a long partition, a front spring and a rear spring, and the mover is composed of a motion shaft and a load bracket. The permanent magnet is bonded between two baffles in the middle of the coil frame, and adjacent permanent magnets are separated by a short partition or a long partition inserted in the grooves on the two baffles in the middle of the coil frame. The front coil and the rear coil are respectively wound between the middle baffle and the two end baffles of the coil frame. The front cover and the rear cover are respectively connected to the front and rear ends of the housing by screws. The coil frame is located in a closed space formed by the housing, the front cover and the rear cover. The front shaft section of the motion shaft is gap-matched with the center hole of the front cover, and the rear shaft section is gap-matched with the center hole of the rear cover. The load bracket is fixed at the front end of the motion shaft. The motion shaft and the load bracket slide forward and backward together under the constraints of the front cover and the rear cover. The front spring and the rear spring are sleeved on the outside of the boss of the front cover and the rear cover and are fixedly connected thereto.

[0006] Preferably, the length of the shell is within 10-40 mm (including the boundary); the outer diameter of the cylindrical part of the shell is within 8-30 mm (including the boundary).

[0007] Preferably, the motion shaft is composed of a front shaft section, an armature, and a rear shaft section, wherein the front shaft section or the rear shaft section has at least one shaft section whose cross-sectional shape can limit rotation around the axis direction. A section at the end of the front shaft section is a shaft section whose cross-sectional shape can limit rotation around the axis direction, so as to connect the load bracket.

[0008] Preferably, the permanent magnet is a fan-shaped structure, the magnetization direction is radial, and the central angle of the fan includes but is not limited to 90°. All designs that can be spliced ​​into a circle by multiple fan-shaped permanent magnets are protected by the patent.

[0009] Preferably, the coil frame comprises four baffles, two middle baffles are cut with partition grooves, and the four baffles are dug with semicircular holes at the same position on the edge.

[0010] Preferably, the front cover and the rear cover have holes on one side of the edge, and a boss is arranged inside the end cover. The center hole of at least one of the front cover and the rear cover can limit the rotation of the motion shaft around the axis direction.

[0011] Preferably, the total mass of the miniature linear position switching device is within 50g.

[0012] Preferably, the form of 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 frames, laser brackets, etc. that can match the motion axis.

[0013] Preferably, the miniature linear position switching device can be transformed into a two-state miniature linear positioning mechanism after removing the front spring and the rear spring. This design is also within the protection of the present invention.

[0014] Preferably, the fixing ears of the housing include but are not limited to the current form, and all fixing ears that can connect the present invention with other devices are within the protection scope of the present invention.

[0015] Compared with other existing positioning mechanisms, the present invention has the following beneficial effects:

[0016] 1. Small volume. The outer diameter of the present invention is in the range of 8-30 mm, and the total length of the shell is in the range of 10-40 mm. The size is significantly smaller than that of the existing linear positioning mechanism, which greatly saves space.

[0017] 2. Lightweight: The weight of the present invention is less than 50g, which is significantly smaller than the existing linear positioning mechanism. Compared with the existing mechanism, it is more suitable for use in aircraft and reduces the load mass.

[0018] 3. Easy to drive. The front coil and the rear coil in the motor of the present invention are in series, and the actuation of the present invention can be realized by applying a fixed voltage or current pulse. Compared with other existing linear brushless motors, it saves the volume and mass of the larger drive controller and does not require complex PWM signals.

[0019] 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 moving shaft to move. When the moving shaft is at the end positions on both sides, the rotor will be attracted and move toward the middle position after power is turned on; when the moving shaft is in the middle position, the rotor will be attracted and rotate toward one end position 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 20W, and the power consumption of one drive is less than 2J, which effectively saves energy on the mobile carrier.

[0020] 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.

[0021] 6. High positioning accuracy. In the present invention, the three limit positions of the motion axis are the front position, the middle position, and the rear position. Both end limits are mechanical limits, which are positioned by the tenon at the bottom of the lens barrel being clamped on the end face of the groove of the bottom hole of the shell, and have high accuracy. The middle limit is a spring limit, which is limited to the middle position by the interaction force of the front spring and the rear spring, and the error can be limited to ±0.5mm.

[0022] 7. It has the function of power-off self-locking. The present invention can realize power-off self-locking in three positions. When disturbed, it can automatically return to the original position within a certain distance 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 linear positioning mechanism.

[0023] 8. Long service life. The coil in the motor of the present invention is in a state of no current passing through most of the time, so that the present invention has a long electrical life. The friction between the central hole wall of the front and rear covers of the motor and the moving shaft is extremely small, so that the present invention has a long mechanical life. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is an isometric view of a miniature linear position switching device of the present invention;

[0025] Figure 2 It is a front view of a miniature linear position switching device of the present invention;

[0026] Figure 3It is a top view of a miniature linear position switching device of the present invention;

[0027] Figure 4 It is a side sectional view of a miniature linear position switching device of the present invention;

[0028] Figure 5 It is an exploded view of a miniature linear position switching device of the present invention.

[0029] Among them, 1: load bracket; 2: shell; 3: moving shaft; 4: front cover; 5: rear cover; 6: coil frame; 7a: front coil; 7b: rear coil; 8: permanent magnet; 9a: short partition; 9b: long partition; 10: motor; 11a: front spring; 11b: rear spring. DETAILED DESCRIPTION

[0030] 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.

[0031] like Figure 1-Figure 5 As shown, a miniature linear position switching device of the present invention includes a load bracket 1 and a motor 10.

[0032] The stator of the motor 10 is composed of a housing 2, a front cover 4, a rear cover 5, a coil frame 6, a front coil 7a, a rear coil 7b, a permanent magnet 8, a short partition 9a, a long partition 9b, a front spring 11a, and a rear spring 11b, and the mover is a motion shaft 3. The permanent magnet 8 is bonded between the two baffles in the middle of the coil frame 6, and the adjacent permanent magnets 8 are separated by a short partition 9a or a long partition 9b inserted in the grooves on the two baffles in the middle of the coil frame 6. The front coil 7a and the rear coil 7b are respectively wound between the middle baffle and the two end baffles of the coil frame 6. The front cover 4 and the rear cover 5 are respectively connected to the front and rear ends of the housing 2 by screws. The coil frame 6 is located in a closed space formed by the housing 2, the front cover 4, and the rear cover 5. The front shaft section of the motion shaft 3 is gap-matched with the center hole of the front cover 4, and the rear shaft section is gap-matched with the center hole of the rear cover 5. The load bracket 1 is fixed at the front end of the motion shaft 3. The motion shaft 3 and the load bracket 1 slide forward and backward together under the constraints of the front cover 4 and the rear cover 5. The front spring 11a and the rear spring 11b are sleeved on the outer sides of the bosses of the front end cover 4 and the rear end cover 5 and are fixedly connected thereto.

[0033] Preferably, the length of the housing 2 is within 10-40 mm (including the boundary); the outer diameter of the cylindrical part of the housing 2 is within 8-30 mm (including the boundary). The volume of the present invention is effectively reduced, making the structure more compact. The housing 2, the front cover 4, the rear cover 5, the permanent magnet 8, and the motion shaft 3 together constitute the magnetic circuit of the present invention.

[0034] Preferably, the motion shaft 3 is composed of a front shaft section, an armature, and a rear shaft section, wherein at least one of the front shaft section or the rear shaft section has a shaft section whose cross-sectional shape can limit rotation around the axis. A section at the end of the front shaft section is a shaft section whose cross-sectional shape can limit rotation around the axis to connect the load bracket 1. The cross-sectional shape can be square, hexagonal, semicircular, butterfly-shaped, etc., to suppress the possible rotation around the axis of the motion shaft 3 during movement.

[0035] Preferably, the permanent magnet 8 is a fan-shaped structure, the magnetization direction is radial, and the fan-shaped central angle includes but is not limited to 90°. All designs that can be spliced ​​into a circle by multiple fan-shaped permanent magnets 8 are protected by the present invention. The permanent magnet 8 can provide continuous radial magnetic flux without power, so that the moving shaft 3 is self-locked on the boss of the front cover 4 or the rear cover 5. The example in the present invention is 4 fan-shaped permanent magnets 8 with a central angle of 90°. The shape and number of the permanent magnets 8 can be changed according to actual operation and assembly requirements to achieve the self-locking goal.

[0036] Preferably, the coil skeleton 6 contains four baffles, two middle baffles are cut with baffle grooves, and the four baffles are dug with semicircular holes at the same position on the edge. The short baffle 9a and the long baffle 9b can be installed in the baffle grooves to block the adjacent permanent magnets 8 and locate the circumferential position of the permanent magnets 8. The short baffle 9a is used for the baffle grooves with semicircular holes, and the long baffle 9b is used for other baffle grooves. The semicircular holes are designed for the connection between the front coil 7a and the rear coil 7b and the length required for the wire to extend out of the present invention.

[0037] Preferably, the front end cover 4 and the rear end cover 5 have holes dug on one side of the edge, and a boss is provided on the inner side of the end cover. The hole shape of the center hole of the rear end cover 5 can limit the rotation of the motion shaft 3 around the axis direction. The inner and outer diameters of the boss on the inner side of the end cover can be adjusted according to the requirements of the self-locking force, and the height of the boss can be adjusted according to the actuation distance required for switching the lens. The hole shape in the front end cover 4 and the rear end cover 5 should correspond to the cross-sectional shape of the front shaft section and the rear shaft section of the motion shaft 3.

[0038] The total mass of the invention is within 50g. The mass is small, which reduces the total mass of the laser equipment and lightens the load of the carrier.

[0039] Preferably, the form of the load bracket 1 is not limited to the form in the drawing of the present invention, and also includes all single-hole and multi-hole load brackets that can match the motion axis. The load bracket 1 and the motion axis 3 are glued together, and a suitable type of load bracket 1 can be selected according to actual needs.

[0040] Preferably, the present invention can be transformed into a two-state micro linear positioning mechanism after removing the front spring 11a and the rear spring 11b, and this design is also within the protection of the present invention. Without removing the spring, it can also be used as a two-state by increasing the driving current.

[0041] Preferably, the fixing ears of the housing 2 include but are not limited to the current form, and all fixing ears that can connect the present invention with other devices are within the protection scope of the present invention. The spacing, number and size of the fixing ears can be determined according to actual assembly needs.

[0042] The working principle of the present invention is as follows: the miniature linear position switching device has three states when it is powered off and stationary, that is, the motor rotor is self-locked in the front position, the middle position, and the rear position. The magnetic circuit of the permanent magnet 8 is divided into two paths through the housing 3, one path passes through the front cover 4 and the moving shaft 3 back to the permanent magnet 8, and the other path passes through the rear cover 5 and the moving shaft 3 back to the permanent magnet 8. The moving shaft 3 is made of high magnetic permeability material, and the thicker part in the middle section is the armature part. When the thicker part in the middle section is close to one of the end positions, the magnetic resistance on this side is smaller than the magnetic resistance on the other side, so that the magnetic field is more inclined to pass through this side. When the moving shaft 3 is powered off and self-locked at the end position, since one end of the armature of the moving shaft 3 is in contact with the boss end face of the front cover 4 or the rear cover 5, the magnetic resistance is small, and the magnetic field of the permanent magnet 8 flows more from there, forming a magnetic pole on the boss end face, and attracting the moving shaft 3 to the boss end face. When the motion shaft 3 is powered off and self-locked in the middle position, it is balanced to a position where the thrusts of the two springs are equal under the thrust of the front spring 11a and the rear spring 11b. The material and size of the front spring 11a and the rear spring 11b are exactly the same, so the position where the thrusts of the two springs are equal is the middle position, and the limit accuracy here is about 0.5mm.

[0043] The coil skeleton 6 of the motor 10 is respectively wound with a front coil 7a and a rear coil 7b, and the two coils are in series and have the same excitation direction. When the drive motor 10 is actuated, if the motion shaft 3 is in the front position at this time, after applying the current in the correct direction, the magnetic field provided by the front coil 7a will release the magnetic field on the boss of the front cover 4, so that the motion shaft 3 loses the self-locking state. The magnetic field generated by the rear coil 7b and the permanent magnet 8 will attract the motion shaft 3 to move in the direction of the rear cover 5, and the front spring 11a will push it to move at the same time. When the motion shaft 3 moves to a position close to the middle position, it will contact the rear spring 11b and begin to compress the rear spring 11b. If the power is cut off when it is close to the middle position, the motion shaft 3 will perform damping vibration under the joint action of the front spring 11a and the rear spring 11b, and balance to the middle position within 1s. If the power is not cut off near the middle position, the motion shaft 3 will continue to move toward the rear cover 5 until it is attracted by the end face of the boss of the rear cover 5. The movement process from back to front is the same as this process, but in the opposite direction, and will not be repeated. This actuation principle has the characteristics of high speed and low power consumption which cannot be matched by current existing solutions.

[0044] When the miniature linear position switching device is actuated, if a smaller current and a shorter pulse time are applied to the front coil 7a and the rear coil 7b, the mover will move to the middle position; if a larger current and a slightly longer pulse time are applied, the mover can directly perform end-to-end actuation. The time for both switching does not exceed 0.1s.

[0045] Preferably, the load bracket 1 is fixed to the motion axis by gluing, and the lens is glued to the load bracket 1. The load bracket 1 can be not only in the form of three 5mm lens positions horizontally as shown in the figure, but also in other numbers, other apertures and other distribution forms.

[0046] Except for the detachable load bracket 1 and the moving shaft 3 that are exposed in the housing 2, the remaining parts of the miniature linear position switching device are wrapped inside by the housing 2, the front cover 4, and the rear cover 5, which has higher equipment safety and human-machine safety and is not easy to be damaged or hurt.

[0047] Preferably, the mounting surface of the miniature linear position switching device is the bottom of the housing 2, and is connected to the bottom plate of the laser device by means of four fixing ears on the left and right sides of the housing 2. The light input direction can be parallel to the mounting surface, or Figure 1 The load bracket 1 is installed parallel to the mounting surface so that the light direction is perpendicular to the mounting surface.

[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 miniature linear position switching device, characterized in that: The invention comprises a load bracket (1) and a motor (10); the stator of the motor (10) comprises a housing (2), a front end cover (4), a rear end cover (5), a coil frame (6), a front coil (7a), a rear coil (7b), a permanent magnet (8), a short partition (9a), a long partition (9b), a front spring (11a), and a rear spring (11b); the mover is a motion shaft (3); the permanent magnet (8) is bonded between two baffles in the middle of the coil frame (6), and adjacent permanent magnets (8) are separated by a short partition (9a) or a long partition (9b) inserted into grooves on the two baffles in the middle of the coil frame (6); the front coil (7a) and the rear coil (7b) are respectively wound on the coil frame (6) and the rear coil (7b) is wound on the coil frame (6) and the rear coil (7a) is wound on the coil frame (6) and the rear coil (7b ... between the middle baffle plate and the two end baffle plates; the front end cover (4) and the rear end cover (5) are connected to the front and rear ends of the housing (2) respectively by screws; the coil skeleton (6) is located in the closed space formed by the housing (2), the front end cover (4) and the rear end cover (5); the front shaft section of the motion shaft (3) is clearance-matched with the center hole of the front end cover (4), and the rear shaft section is clearance-matched with the center hole of the rear end cover (5); the load bracket (1) is fixed to the front end of the motion shaft (3); the motion shaft (3) and the load bracket (1) slide forward and backward together under the constraints of the front end cover (4) and the rear end cover (5); the front spring (11a) and the rear spring (11b) are sleeved on the outer sides of the bosses of the front end cover (4) and the rear end cover (5) and are fixedly connected thereto; The motion shaft (3) is composed of a front shaft section, an armature, and a rear shaft section, wherein the front shaft section or the rear shaft section has at least one shaft section whose cross-sectional shape can limit rotation around the axis direction; a section at the end of the front shaft section is a shaft section whose cross-sectional shape can limit rotation around the axis direction, so as to connect to the load bracket (1); The coil frame (6) comprises four baffles, two middle baffles are cut with baffle grooves, and the four baffles are dug with semicircular holes at the same position on the edge; The load support (1) includes any mirror frame or laser support that can match the motion axis; The miniature linear position switching device realizes power-off self-locking in the front position, middle position and rear position. When disturbed, it automatically returns to the original position within a certain distance range by relying on the magnetic force of the permanent magnet, so as to prevent the carrier vibration from changing the state of the linear positioning mechanism. After removing the front spring and rear spring, it becomes a two-state micro linear positioning mechanism.

2. A miniature linear position switching device according to claim 1, characterized in that: The length of the outer shell (2) is within 10 to 40 mm; the outer diameter of the cylindrical portion of the outer shell (2) is within 8 to 30 mm.

3. A miniature linear position switching device according to claim 1, characterized in that: The permanent magnet (8) is a fan-shaped structure, the magnetization direction is radial, and the central angle of the fan-shaped structure is 90°.

4. A miniature linear position switching device according to claim 1, characterized in that: The front end cover (4) and the rear end cover (5) have holes dug on one side of the edge, and bosses are arranged on the inner sides of the end covers; the center hole of at least one of the front end cover (4) and the rear end cover (5) is capable of limiting the movement shaft (3) from rotating around the axis direction.

5. The miniature linear position switching device according to claim 1, characterized in that: The total mass of the micro-sized linear position switching device is within 50g.

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