A multi-turn non-contact potentiometer based on the lead screw principle

Abstract

The present invention relates to the technical field of electronic components, and particularly to a multi-turn non-contact potentiometer based on the lead screw principle, comprising: a first end cover and a second end cover are respectively fixed at both ends of the housing, and the first through hole corresponds to the second through hole; a threaded portion is provided on the lead screw shaft, one end of which extends into the first through hole and the other end extends into the second through hole; a threaded hole is provided at the center of the slider, and the threaded hole is adapted to the threaded portion so that the slider can move along the axis of the lead screw shaft. A magnet is arranged on the slider and moves with the slider. The detection circuit board is used to detect the change in the magnetic field intensity generated by the movement of the magnet; for the guide shaft, it is symmetrically arranged on both sides of the lead screw shaft and is used to guide the slider when it moves. Beneficial effects: In addition to realizing the multi-turn of the non-contact potentiometer, at the same time, this structure also has the advantages of small volume and front and rear limiting functions.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic components, and particularly to a multi-turn non-contact potentiometer based on the lead screw principle. Background Art

[0002] A multi-turn potentiometer is a common angular displacement sensor, which is widely used in an automatic control system to feedback an angular position signal greater than one turn. The traditional multi-turn potentiometer is of a wire-wound resistor type. Since there is wear between the wire-wound resistor and the brush during movement, the service life of this type of multi-turn potentiometer is short.

[0003] In recent years, various non-contact technologies have been applied to the field of potentiometers. Among them, the non-contact potentiometer based on the Hall principle has largely replaced the traditional potentiometer due to high component integration and high cost performance. However, the Hall sensing chip can usually only detect the angular change within 360°, that is, a single turn. If multi-turn angle measurement is to be realized, there are usually two methods: (1) One method is to use a multi-stage gear drive and two chips to detect the angle and the number of turns respectively. Not only is the structure of the product complex and the volume large, but also the cumulative errors of the gear shape and assembly may affect the detection accuracy of the product, and more processing needs to be carried out in the algorithm; (2) Another method is to use a battery to memorize the number of turns passed. Although this method has a simple structure, if the power-off time is too long and the battery runs out of power, the information on the number of turns will be lost.

[0004] The above two solutions also have a common feature that when the number of turns reaches the set maximum value and continues to increase, it will return to the minimum value. The traditional wire-wound resistor multi-turn potentiometer cannot rotate beyond the mechanical angle and can only reverse after rotating to the limit position in the forward or reverse direction. Therefore, the multi-turn non-contact potentiometers of the above two solutions cannot completely replace the wire-wound resistor multi-turn potentiometer. Summary of the Invention

[0005] In view of the above problems existing in the prior art, a multi-turn non-contact potentiometer based on the lead screw principle is provided herein.

[0006] The specific technical solution is as follows:

[0007] The present invention includes a multi-turn non-contact potentiometer based on the lead screw principle, which includes a housing, a first end cap, a second end cap, a lead screw shaft, a slider, a magnet and a detection circuit board, and further includes:

[0008] A first through hole is provided at the center of the first end cap;

[0009] A second through hole is provided at the center of the second end cap;

[0010] The first end cap and the second end cap are respectively fixed to both ends of the housing, and the first through hole corresponds to the second through hole;

[0011] The lead screw shaft is provided with a threaded portion. The lead screw shaft is disposed within the housing, with one end extending into the first through hole and the other end extending into the second through hole.

[0012] A threaded hole is provided at the center of the slider. The threaded hole is adapted to the threaded portion so that the slider can move along the axis of the lead screw shaft. The magnet is disposed on the slider and moves with the slider. The detection circuit board is used to detect the change in magnetic field strength generated by the movement of the magnet.

[0013] A pair of guide shafts are symmetrically disposed on both sides of the lead screw shaft and maintain a preset distance from the lead screw shaft. Both ends of the pair of guide shafts are respectively fixed to the first end cover and the second end cover, and are used to guide the slider when it moves.

[0014] Preferably, a pair of fixing holes are respectively provided on the first end cover and the second end cover. The pair of fixing holes on the first end cover are symmetrically disposed on both sides of the first through hole, and the pair of fixing holes on the second end cover are symmetrically disposed on both sides of the second through hole, and are used to limit the pair of guide shafts.

[0015] Preferably, the slider is disposed between the lead screw shaft and the first end cover, and the threaded hole is correspondingly disposed with the first through hole so that the lead screw shaft passes through the threaded hole and then extends into the first through hole for fixation.

[0016] Preferably, the slider further includes a pair of third through holes, which are symmetrically disposed on both sides of the threaded hole.

[0017] Preferably, a groove is provided on one side of the slider corresponding to the detection circuit board. The shape and size of the groove are adapted to the magnet, and are used to fix the magnet.

[0018] Preferably, the detection circuit board includes a Hall element and a wire. The wire is used to connect to an external device and transmit the change in magnetic field strength detected by the Hall element to the external device.

[0019] Preferably, a card slot is provided within the housing for fixing the detection circuit board above the lead screw shaft, and the side of the detection circuit board having the Hall element faces the lead screw shaft.

[0020] Preferably, a plurality of screw assembly holes are respectively provided at both ends of the housing. The first end cover and the second end cover are respectively fixed to both sides of the housing by a plurality of screws.

[0021] Preferably, one side of the second end cap facing away from the lead screw shaft is provided with an extension portion. The extension portion is a hollow structure and is in communication with the second through hole. One end of the lead screw shaft away from the threaded portion penetrates through the second through hole and extends into the extension portion to be connected to a detection rotation angle component and rotates synchronously with the detection rotation angle component.

[0022] Preferably, one side of each of the first end cap and the second end cap facing the interior of the housing is provided with a convex structure. The first through hole is provided on the convex structure of the first end cap, and the second through hole is provided on the convex structure of the second end cap.

[0023] The technical solution of the present invention has the following advantages or beneficial effects: A multi-turn non-contact potentiometer based on the lead screw principle is provided, which converts the rotational motion of the lead screw shaft into the linear motion of the slider and the magnet. The actual rotation angle of the lead screw shaft is calculated by detecting the change in the magnetic field strength of the magnet by the Hall element of the detection circuit board. In addition to realizing the multi-turn of the non-contact potentiometer, this structure also has the advantages of small volume and front and rear limit functions. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] With reference to the accompanying drawings, the embodiments of the present invention will be described more fully. However, the accompanying drawings are only for illustration and explanation and do not constitute a limitation on the scope of the present invention.

[0025] Figure 1 It is an exploded structure diagram of the multi-turn non-contact potentiometer in the embodiment of the present invention;

[0026] Figure 2 It is a sectional structure diagram of the multi-turn non-contact potentiometer in the embodiment of the present invention;

[0027] Figure 3 It is a schematic diagram of the magnetic induction part of the multi-turn non-contact potentiometer in the embodiment of the present invention;

[0028] Figure 4 It is an electrical schematic diagram of the multi-turn non-contact potentiometer in the embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts fall within the protection scope of the present invention.

[0030] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0031] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but it is not intended to limit the present invention.

[0032] The present invention includes a multi-turn non-contact potentiometer based on the lead screw principle, as Figure 1 and 2 shown, including a housing 7, a first end cap 1, a second end cap 6, a lead screw shaft 4, a slider 2, a magnet 3 and a detection circuit board 8, and further including:

[0033] A first through hole 1a is provided at the center of the first end cap 1;

[0034] A second through hole 6a is provided at the center of the second end cap 6;

[0035] The first end cap 1 and the second end cap 6 are respectively fixed at both ends of the housing 7, and the first through hole 1a corresponds to the second through hole 6a;

[0036] The lead screw shaft 4 is provided with a threaded portion 4a. The lead screw shaft 4 is arranged inside the housing 7, one end of which extends into the first through hole 1a, and the other end extends into the second through hole 6a;

[0037] A threaded hole 2a is provided at the center of the slider 2, and the threaded hole 2a is adapted to the threaded portion 4a so that the slider can move along the axis of the lead screw shaft 4. The magnet 3 is arranged on the slider 2 and moves with the slider 2. The detection circuit board 8 is used to detect the change in the magnetic field intensity generated by the movement of the magnet 3;

[0038] A pair of guide shafts 5 are symmetrically arranged on both sides of the lead screw shaft 4 and maintain a preset distance from the lead screw shaft 4. Both ends of the pair of guide shafts 5 are respectively fixed to the first end cap 1 and the second end cap 6, and are used to guide the slider 2 when it moves.

[0039] Specifically, the lead screw shaft 4 is a shaft-type part with a threaded portion. One end of the lead screw shaft 4 away from the threaded portion extends into the second through hole 6a of the second end cap 6, and the other end of the lead screw shaft 4 extends into the first through hole 1a of the first end cap 1. Supported by both ends of the second end cap 6 and the first end cap 1, the lead screw shaft 4 can rotate around the first through hole 1a and the second through hole 6a. At the same time, due to the limitation at both ends of the second end cap 6 and the first end cap 1, the lead screw shaft 4 cannot move axially.

[0040] Specifically, the threaded hole 2a at the center of the slider 2 mates with the threaded portion 4a of the lead screw shaft 4, so that the rotation of the lead screw shaft 4 can drive the slider 2 to move along the axis of the lead screw shaft 4. When the slider 2 moves to the limit position along the axis direction of the lead screw shaft 4, it will be restricted by the first end cover 1 and the second end cover 6 and cannot continue to move in this direction, and can only retract in the opposite direction. The distance between the limit positions that the slider 2 can move is the mechanical stroke, which can be converted into the number of rotations of the lead screw shaft 4 as needed. Assuming the mechanical stroke of the slider 2 is L and the pitch of the lead screw shaft 4 is P, then the number of rotations of the lead screw shaft 4 is L / P. By simply adjusting the mechanical stroke L of the slider 2 and the pitch P of the lead screw shaft 4, multi-turn non-contact potentiometers with different numbers of turns can be obtained.

[0041] Specifically, a guide shaft is provided on each side of the lead screw shaft 4. Both ends of a pair of guide shafts 5 are fixed by the first end cover 1 and the second end cover 6 respectively to ensure that the guide shafts 5 cannot move axially. The guide shafts 5 on both sides of the slider 2 are used to guide the slider 2 to ensure that the slider 2 does not rotate in the circumferential direction during movement, thereby ensuring the detection accuracy.

[0042] Furthermore, the detection circuit board 8 includes a Hall element 8a and a wire 8b. The Hall element 8a is used to detect the magnetic field intensity of the magnet 3 on the slider 2. The magnet 3 can move along with the slider 2, and the detected magnetic field intensity is different when the magnet 3 moves to different positions. The wire 8b is used to connect to external devices and transmit the change in the magnetic field intensity detected by the Hall element 8a to the external devices.

[0043] As a preferred embodiment, as Figure 1 shown, a pair of fixing holes are respectively provided on the first end cover 1 and the second end cover 6. A pair of fixing holes 1b on the first end cover 1 are symmetrically arranged on both sides of the first through hole 1a, and a pair of fixing holes 6b on the second end cover 6 are symmetrically arranged on both sides of the second through hole 6a, for limiting a pair of guide shafts 5. The two guide shafts 5 in this embodiment are shaft-type parts with thin shoulders at both ends. The thin shoulders at both ends of the two guide shafts 5 are respectively inserted into a pair of fixing holes 1b of the first end cover 1 and a pair of fixing holes 6b of the second end cover 6 to ensure that the guide shafts 5 cannot move axially.

[0044] As a preferred embodiment, as Figure 2 shown, the slider 2 is arranged between the lead screw shaft 4 and the first end cover 1, and the threaded hole 2a is correspondingly arranged with the first through hole 1a, so that the lead screw shaft 4 passes through the threaded hole 2a and extends into the first through hole 1a for fixation.

[0045] As a preferred embodiment, as Figure 1As shown, the slider 2 further includes a pair of third through-holes 2b, symmetrically arranged on both sides of the threaded hole 2a. The third through-holes 2b are small guiding holes, respectively sleeved on two guiding shafts 5 to ensure that the slider 2 does not rotate in the circumferential direction during movement.

[0046] As a preferred embodiment, as Figure 1 shown, one side of the slider 2 corresponding to the detection circuit board 8 is provided with a groove 2c, and the shape and size of the groove 2c are adapted to the magnet 3 for fixing the magnet 3. A clamping groove is provided in the housing 7 for fixing the detection circuit board 8 above the lead screw shaft 4, and the surface of the detection circuit board 8 with the Hall element 8a faces the lead screw shaft 4.

[0047] The magnet 3 in this embodiment is square. The detection circuit board 8 is installed in the clamping groove above the interior of the housing 7, and electronic components including the Hall element 8a are soldered on the detection circuit board 8. As Figure 3 shown, the Hall element 8a is within the magnetic field range generated by the magnet 3, and simultaneously detects the changes in the magnetic field intensities in the Y direction and the Z direction. As the slider 2 drives the magnet 3 to move, the magnetic field intensities in the Y and Z directions detected by the Hall element 8a continuously change. Through data processing, the changes in the magnetic field intensity are transmitted to an external device in the form of an analog quantity (such as 0 - 5V, 0 - 10V, 4 - 20mA, etc.) or a digital quantity (such as SER, SSI, SPI, etc.) through the wire 8b.

[0048] As a preferred embodiment, as Figure 1 shown, a plurality of screw assembly holes 7a are respectively provided at both ends of the housing 7. The first end cover 1 and the second end cover 6 are respectively fixed to both sides of the housing 7 by a plurality of screws 9. The housing 7 is a square tube-shaped part with four screw holes at each end. Both the first end cover 1 and the second end cover 6 are square parts with through-holes in the center, and both have four through-holes corresponding to the positions of the screw holes in the housing 7. The first end cover 1 and the second end cover 6 are each fixed to both sides of the housing 7 by four screws 9 to form a complete cavity. It should be noted that the first end cover 1 and the second end cover 6 are fixed to the housing 7 by screws only as a preferred embodiment, and can also be fixed by other means, such as by rivets, buckles, etc.

[0049] As a preferred embodiment, as Figure 1 shown, one side of the second end cover 6 facing away from the lead screw shaft 4 is provided with an extension part 6c. The extension part 6c is a hollow structure and is in communication with the second through-hole 6a. One end of the lead screw shaft 4 away from the threaded part 4a penetrates through the second through-hole 6b and extends into the extension part 6c to be connected with the detection angle component and rotate synchronously with the detection angle component.

[0050] As a preferred embodiment, as Figure 1As shown in the figure, a convex structure is provided on each of the surfaces of the first end cap 1 and the second end cap 6 facing the inside of the housing 7. The first through hole 1a is provided on the convex structure of the first end cap 1, and the second through hole 6a is provided on the convex structure of the second end cap 6. There are convex structures on both the first end cap 1 and the second end cap 6 to ensure that after the first end cap 1 and the second end cap 6 are respectively assembled to both ends of the housing 7, the central holes of the first end cap 1 and the second end cap 6 are concentric.

[0051] As a preferred embodiment, the electrical principle of the multi-turn non-contact potentiometer in the embodiment of the present invention is as Figure 4 shown. The electrical part is mainly divided into four parts, namely, an input power supply processing unit 10, a sensor power supply unit 11, a sensing unit 12, and a signal processing unit 13. The input power supply processing unit 10 includes a magnetic bead FB1, a diode D1, and a TVS tube D2. The function of the magnetic bead FB1 is to suppress the high-frequency noise and spike interference of the input power supply; the function of the diode D1 is to provide reverse connection protection; the function of the TVS tube D2 is to suppress the transient high voltage at the power supply end and protect the components at the subsequent stage. The core component of the sensor power supply unit 11 is U1, that is, the LM317LIPK power integration module. This module can provide a stable and adjustable working voltage for the subsequent sensing unit and play a role in suppressing ripple and overcurrent protection. R5, R6, and R7 are the voltage regulation feedback resistors of U1. C1 is the filtering capacitor at the input end of U1, which is used to improve the smoothness of the input power supply. C2 is the filtering capacitor at the output end of U1, which is used to improve the smoothness of the output signal. The core component of the sensing unit 12 is U2 (that is, the Hall element 8a) is MLX90365. The function of this element is to detect the change in the magnetic field intensity and transmit this change as a basic 0-5V voltage. C5 is the output filtering capacitor of U2, which is used to improve the smoothness of the output signal. R1 is the output load resistor of U2, which is used to adjust the loop current. The core component of the signal processing unit 13 is U3, that is, the OPA172 operational amplifier. The function of this element is to amplify the 0-5V voltage signal output by U2 to the voltage signal actually required, such as 0-10V, etc. R2 and R3 are the amplification feedback resistors of U3. C3 is the filtering capacitor at the input end of U3, which is used to improve the smoothness of the input power supply. R4 is the output load resistor of U3, which is used to adjust the loop current. The signal processed by this unit is finally transmitted to an external device. This unit is not limited to the above design and can be changed to a current conversion module to output a current signal according to actual needs, or converted to a digital quantity signal by an analog-to-digital conversion module for output, or this unit can be cancelled to directly output the basic 0-5V voltage of the U1 part.

[0052] Through the above technical solution, in the above circuit, since the magnetic field change generated by the linear movement of the magnetic steel 3 detected by the Hall element 8a is not completely linear, the linearity can be greatly improved by performing multi-point correction on the output signal.

[0053] The technical solution of the present invention has the following advantages or beneficial effects: A multi-turn non-contact potentiometer based on the lead screw principle is provided, which converts the rotational motion of the lead screw shaft into the linear motion of the slider and the magnet, and calculates the actual rotation angle of the lead screw shaft by detecting the change in the magnetic field intensity of the magnet through the Hall element on the detection circuit board. In addition to realizing the multi-turn of the non-contact potentiometer, this structure also has the advantages of small volume and front and rear limit functions.

[0054] The above are only the preferred embodiments of the present invention, and do not limit the implementation manners and protection scope of the present invention accordingly. For those skilled in the art, it should be realized that all the equivalent replacements and obvious changes made by using the description and illustrations of the present invention should be included in the protection scope of the present invention.

Claims

1. A multi-turn non-contact potentiometer based on the lead screw principle, characterized in that, It includes a housing, a first end cap, a second end cap, a lead screw shaft, a slider, a magnet, and a detection circuit board, and further includes: A first through hole is provided at the center of the first end cap; A second through hole is provided at the center of the second end cap; The first end cap and the second end cap are respectively fixed to both ends of the housing, and the first through hole corresponds to the second through hole; The lead screw shaft is provided with a threaded portion, the lead screw shaft is arranged inside the housing, one end thereof extends into the first through hole, and the other end extends into the second through hole; A threaded hole is provided at the center of the slider, and the threaded hole is adapted to the threaded portion so that the slider can move along the axis of the lead screw shaft. The magnet is arranged on the slider and moves with the slider. The detection circuit board is used to detect the change in magnetic field strength generated by the movement of the magnet; A pair of guide shafts are symmetrically arranged on both sides of the lead screw shaft and maintain a preset distance from the lead screw shaft, and both ends of the pair of guide shafts are respectively fixed to the first end cap and the second end cap for guiding the slider when it moves; The detection circuit board includes an input power processing unit, a sensor power unit, a sensing unit, and a signal processing unit; The input end of the input power processing unit is connected to an external power supply, and the output end is respectively connected to the sensor power unit and the signal processing unit; The output end of the sensor power unit is connected to the sensing unit; The output end of the sensing unit is connected to the signal processing unit; The input power processing unit directly supplies power to the signal processing unit and supplies power to the sensing unit through the sensor power unit; The sensing unit is used to realize the function of the detection circuit board to detect the change in magnetic field strength generated by the movement of the magnet; The signal processing unit is used to process the signal output by the sensing unit and then transmit it to an external device.

2. The multi-turn non-contact potentiometer according to claim 1, wherein, A pair of fixing holes are respectively provided on the first end cap and the second end cap. The pair of fixing holes on the first end cap are symmetrically arranged on both sides of the first through hole, and the pair of fixing holes on the second end cap are symmetrically arranged on both sides of the second through hole for limiting the pair of guide shafts.

3. The multi-turn non-contact potentiometer according to claim 1, wherein The slider is arranged between the lead screw shaft and the first end cap, and the threaded hole corresponds to the first through hole so that the lead screw shaft passes through the threaded hole and then extends into the first through hole for fixing.

4. The multi-turn non-contact potentiometer according to claim 3, characterized in that, The slider further includes a pair of third through holes symmetrically arranged on both sides of the threaded hole.

5. The multi-turn non-contact potentiometer according to claim 1, characterized in that One side of the slider corresponding to the detection circuit board is provided with a groove, and the shape and size of the groove are adapted to the magnet for fixing the magnet.

6. The multi-turn non-contact potentiometer according to claim 1, wherein, The detection circuit board includes a Hall element and a wire. The wire is used to connect to an external device and transmit the change in magnetic field strength detected by the Hall element to the external device.

7. The multi-turn non-contact potentiometer according to claim 6, characterized in that, A card slot is provided inside the housing for fixing the detection circuit board above the lead screw shaft, and the surface of the detection circuit board with the Hall element faces the lead screw shaft.

8. The multi-turn non-contact potentiometer according to claim 1, characterized in that A plurality of screw assembly holes are respectively provided at both ends of the housing, and the first end cover and the second end cover are respectively fixed to both sides of the housing by a plurality of screws.

9. The multi-turn non-contact potentiometer according to claim 1, wherein, One side of the second end cover facing away from the lead screw shaft is provided with an extension part. The extension part is of a hollow structure and is communicated with the second through hole. One end of the lead screw shaft far from the threaded part penetrates through the second through hole and extends into the extension part to be connected with a detection angle component and rotates synchronously with the detection angle component.

10. The multi-turn non-contact potentiometer according to claim 1, characterized in that, One side of each of the first end cover and the second end cover facing the inside of the housing is provided with a convex structure. The first through hole is arranged on the convex structure of the first end cover, and the second through hole is arranged on the convex structure of the second end cover.

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