阅读说明：本技术 一种线性位移高精度测量装置及缝纫机 (Linear displacement high-precision measuring device and sewing machine ) 是由 于恒基 张涵 甘志强 杨通 于 2020-08-24 设计创作，主要内容包括：本发明提供一种线性位移高精度测量装置及缝纫机,线性位移高精度测量装置包括线性霍尔传感器、以及在同一平面内平行间隔放置的第一磁铁和第二磁铁,第一磁铁朝向线性霍尔传感器的磁极与第二磁铁朝向线性霍尔传感器的磁极相反,线性霍尔传感器中的芯片与第一磁铁和第二磁铁的安装平面相平行、且上下相对设置,线性霍尔传感器在第一磁铁和第二磁铁的中心连线的正上方侧、并沿第一磁铁和第二磁铁的中心连线方向同第一磁铁和第二磁铁相对移动。本发明低成本地实现高精度的线性位移测量,能够适用于较多要求低成本、高精度的应用场合,特别适用于缝纫机中的一些测量,如压脚高度检测、电子膝靠旋转角度检测、音圈电机位置检测等。(The invention provides a linear displacement high-precision measuring device and a sewing machine, wherein the linear displacement high-precision measuring device comprises a linear Hall sensor, a first magnet and a second magnet which are arranged in the same plane at intervals in parallel, the magnetic pole of the first magnet facing the linear Hall sensor is opposite to the magnetic pole of the second magnet facing the linear Hall sensor, a chip in the linear Hall sensor is parallel to the installation plane of the first magnet and the second magnet and is arranged oppositely up and down, and the linear Hall sensor is arranged on the right upper side of the central connecting line of the first magnet and the second magnet and moves relative to the first magnet and the second magnet along the central connecting line direction of the first magnet and the second magnet. The invention realizes high-precision linear displacement measurement with low cost, can be suitable for application occasions with more requirements on low cost and high precision, and is particularly suitable for some measurements in sewing machines, such as presser foot height detection, electronic knee rotation angle detection, voice coil motor position detection and the like.)

1. The utility model provides a linear displacement high accuracy measuring device which characterized in that: the linear Hall sensor comprises a linear Hall sensor (10), a first magnet (20) and a second magnet (30) which are arranged in the same plane at intervals in parallel, wherein the magnetic pole of the first magnet (20) facing the linear Hall sensor (10) is opposite to the magnetic pole of the second magnet (30) facing the linear Hall sensor (10), a chip (11) in the linear Hall sensor (10) is parallel to the installation plane of the first magnet (20) and the installation plane of the second magnet (30) and is arranged oppositely from top to bottom, and the linear Hall sensor (10) moves relative to the first magnet (20) and the second magnet (30) along the central connection line direction of the first magnet (20) and the second magnet (30) at the side right above the central connection line of the first magnet (20) and the second magnet (30).

2. The linear displacement high-precision measuring device according to claim 1, characterized in that: the relative movement range of the linear Hall sensor (10) is the central connecting line area of the first magnet (20) and the second magnet (30).

3. The linear displacement high precision measuring device according to claim 1 or 2, characterized in that: the linear Hall sensor (10) can move linearly, and the first magnet (20) and the second magnet (30) are fixed.

4. The linear displacement high precision measuring device according to claim 1 or 2, characterized in that: the linear Hall sensor (10) is fixed, and the first magnet (20) and the second magnet (30) can synchronously move in a straight line.

5. A sewing machine characterized by: the sewing machine is provided with a linear displacement high-precision measuring device according to any one of claims 1 to 4.

Technical Field

The present invention relates to measuring displacement of an object, and more particularly, to a linear displacement high-precision measuring device and a sewing machine including the same.

Background

The measurement of the displacement of an object is one of the key technologies in industrial automation, and many measurement devices can realize the high-precision measurement of the displacement of the object, but the cost thereof also increases greatly along with the improvement of the precision. In the sewing machine industry, many applications requiring high precision displacement measurement are often prohibitive due to the cost of the displacement measuring device, due to the limited downstream market acceptance faced.

At present, most displacement measuring devices used in sewing machines are composed of a linear hall sensor and a magnet, wherein the linear hall sensor and the magnet can move relatively, the magnet is used for generating a magnetic field, and the displacement of an object is calculated through the electric potential output by the linear hall sensor. Since the output potential of the linear hall sensor should have a linear relationship with the vertical component of the magnetic induction at the position, and actually, in most cases, the spatial magnetic induction distribution is not linear, the output potential of the linear hall sensor is not linear with the change of the position, so that the linear displacement measurement with high precision cannot be realized.

Disclosure of Invention

In view of the above-mentioned drawbacks of the prior art, an object of the present invention is to provide a linear displacement high-precision measuring apparatus capable of realizing high-precision linear displacement measurement at low cost.

In order to achieve the above object, the present invention provides a high-precision measuring device for linear displacement, which includes a linear hall sensor, and a first magnet and a second magnet disposed in parallel and at an interval in the same plane, wherein a magnetic pole of the first magnet facing the linear hall sensor is opposite to a magnetic pole of the second magnet facing the linear hall sensor, a chip in the linear hall sensor is parallel to a mounting plane of the first magnet and the second magnet and is disposed opposite to the mounting plane of the first magnet and the second magnet, and the linear hall sensor moves relative to the first magnet and the second magnet right above a center connecting line of the first magnet and the second magnet and along the center connecting line direction of the first magnet and the second magnet.

Further, the relative movement range of the linear hall sensor is the central connecting line area of the first magnet and the second magnet.

Further, the linear hall sensor can move linearly, and the first magnet and the second magnet are fixed.

Further, the linear hall sensor is fixed, and the first magnet and the second magnet can synchronously move linearly.

The application also provides a sewing machine, wherein the high-precision measuring device for linear displacement is configured in the sewing machine.

As described above, the linear displacement high-precision measuring device and the sewing machine according to the present invention have the following advantageous effects:

the method comprises the steps that a space magnetic field is formed by a first magnet and a second magnet, a height is found through analysis of the space magnetic field, the vertical component of the magnetic induction intensity on a section of path parallel to the central connecting line of the first magnet and the second magnet at the height is linearly changed, the linear Hall sensor is arranged at the height and arranged between the first magnet and the second magnet to relatively move along the central connecting line direction of the first magnet and the second magnet, and therefore the output potential of the linear Hall sensor on the section of path is in a positive proportion relation with the relative displacement between the linear Hall sensor and the first magnet and the second magnet, and the purpose of measuring the linear displacement with high precision is achieved; moreover, the device is simple in structure, easy to implement and low in cost. Therefore, the linear displacement measuring device can realize high-precision linear displacement measurement at low cost, can be suitable for application occasions with more requirements on low cost and high precision, and is particularly suitable for some measurements in a sewing machine, such as presser foot height detection, electronic knee rotation angle detection, voice coil motor position detection and the like.

Drawings

Fig. 1 is a schematic structural diagram of a linear displacement high-precision measuring device in the present application.

Fig. 2 is a schematic diagram of a relationship between a chip and a magnetic field of the linear hall sensor of fig. 1.

Fig. 3 to 5 are graphs showing the relationship between the output potential of the linear hall sensor and the relative displacement between the linear hall sensor and the first and second magnets, measured at different heights of the linear hall sensor.

Description of the element reference numerals

10 linear hall sensor

11 chip

20 first magnet

30 second magnet

Detailed Description

The following description of the embodiments of the present invention is provided for illustrative purposes, and other advantages and effects of the present invention will become apparent to those skilled in the art from the present disclosure.

It should be understood that the structures, proportions, and dimensions shown in the drawings and described herein are for illustrative purposes only and are not intended to limit the scope of the present invention, which is defined by the claims, but rather by the claims. In addition, the terms such as "upper", "lower", "left", "right", "middle" and "one" used in the present specification are for convenience of description only and are not intended to limit the scope of the present invention, and changes or modifications of the relative relationship thereof may be made without substantial technical changes and modifications.

As shown in fig. 1, the present application provides a linear displacement high-precision measuring device, which includes a linear hall sensor 10, and a first magnet 20 and a second magnet 30 disposed in parallel and spaced in the same plane; the first magnet 20 and the second magnet 30 are two same magnets, and the first magnet 20 and the second magnet 30 are arranged side by side to form a pair of magnet groups for generating a space magnetic field; the linear hall sensor 10 is disposed opposite to the installation planes of the first and second magnets 20 and 30. For convenience of description, the side-by-side direction of the first magnet 20 and the second magnet 30 is defined as a left-right direction, and the opposite direction of the linear hall sensor 10 to the installation plane of the first magnet 20 and the second magnet 30 is defined as an up-down direction; the first magnet 20 is disposed on the left side of the second magnet 30, and the linear hall sensor 10 is disposed on the right upper side of the mounting plane of the first magnet 20 and the second magnet 30.

Further, the magnetic pole of the first magnet 20 facing the linear hall sensor 10 is opposite to the magnetic pole of the second magnet 30 facing the linear hall sensor 10; in the view shown in fig. 1, the S-pole of the first magnet 20 is facing upward and the N-pole of the second magnet 30 is facing upward; of course, the N-pole of the first magnet 20 may face upward, the S-pole of the second magnet 30 may face upward, and the upward magnetic pole of the first magnet 20 and the second magnet 30 may face the linear hall sensor 10. The chip 11 of the linear hall sensor 10 is parallel to the installation plane of the first magnet 20 and the second magnet 30, and is disposed opposite to each other, the linear hall sensor 10 is disposed at a height H on the side directly above the center connecting line of the first magnet 20 and the second magnet 30, the height H is found by analyzing the spatial magnetic field formed by the first magnet 20 and the second magnet 30, and satisfies the following conditions: the vertical component of the magnetic induction varies linearly over a path parallel to the line connecting the centers of the first magnet 20 and the second magnet 30 at the height H. When the linear displacement high-precision measuring device is used for measuring, the linear hall sensor 10 and the first magnet 20 and the second magnet 30 can move relatively along the central connecting line direction of the first magnet 20 and the second magnet 30; based on this, the linear hall sensor 10 can be moved linearly, and the first magnet 20 and the second magnet 30 are fixed; alternatively, the linear hall sensor 10 is fixed, and the first magnet 20 and the second magnet 30 may be linearly moved in synchronization. In the present embodiment, the first magnet 20 and the second magnet 30 are fixed, and the linear hall sensor 10 moves linearly in the direction of the line connecting the centers of the first magnet 20 and the second magnet 30 at a height H directly above the line connecting the centers of the first magnet 20 and the second magnet 30.

Further, the center line of the first magnet 20 and the second magnet 30 extends in the left-right direction, and the distance between the first magnet 20 and the second magnet 30 is D. Output potential V of linear Hall sensor 10 and its positionPerpendicular component B of magnetic induction vector B_⊥The relationship between them is: v ═ k × B_⊥K is the proportionality coefficient of the linear hall sensor 10; as shown in FIG. 2, B_⊥B (X, Y, Z) × cos θ, where B is the magnetic induction vector, and θ is the angle between the magnetic induction vector B and the normal of the plane of the chip 11 in the linear hall sensor 10. Therefore, when the distance D between the first magnet 20 and the second magnet 30 is fixed, the spatial magnetic field distribution generated by the first magnet 20 and the second magnet 30 is also fixed, and the vertical component B of the magnetic induction B at the height H is fixed_⊥The output potential of the linear hall sensor 10 is in a positive proportion relation with the relative displacement between the linear hall sensor 10 and the first magnet 20 and the second magnet 30 when the linear hall sensor 10 moves in the motion path parallel to the central connecting line of the first magnet 20 and the second magnet 30 at the height H relative to the first magnet 20 and the second magnet 30 along the central connecting line of the first magnet 20 and the second magnet 30, so that the purpose of measuring the linear displacement with high precision is achieved; moreover, the device is simple in structure, easy to implement and low in cost. Therefore, the linear displacement measuring device can realize high-precision linear displacement measurement at low cost, can be suitable for application occasions with more requirements on low cost and high precision, and is particularly suitable for sewing machines.

Further, the height H of the linear hall sensor 10 from the center-to-center line of the first magnet 20 and the second magnet 30 is related to the distance D between the first magnet 20 and the second magnet 30, and when the distance D between the first magnet 20 and the second magnet 30 increases, the height H of the linear hall sensor 10 from the center-to-center line of the first magnet 20 and the second magnet 30 also increases; when the distance D between the first magnet 20 and the second magnet 30 is decreased, the height H of the linear hall sensor 10 from the central connecting line of the first magnet 20 and the second magnet 30 is also decreased. Such as: when the distance D between the first magnet 20 and the second magnet 30 is 6mm, the height H of the linear hall sensor 10 from the central connecting line of the first magnet 20 and the second magnet 30 is 4.5 mm. More specifically, when the distance D between the first magnet 20 and the second magnet 30 is fixed to 6mm, and when the height H of the linear hall sensor 10 from the center-connecting line of the first magnet 20 and the second magnet 30 is 2.5mm, as shown in fig. 3, the output potential of the linear hall sensor 10 does not have a linear relationship with the relative displacement between the linear hall sensor 10 and the first magnet 20 and the second magnet 30; when the height H of the linear hall sensor 10 from the center connecting line of the first magnet 20 and the second magnet 30 is 4.5mm, as shown in fig. 4, there is a strict linear relationship between the output potential of the linear hall sensor 10 and the relative displacement between the linear hall sensor 10 and the first magnet 20 and the second magnet 30; when the height H of the linear hall sensor 10 from the center-connecting line of the first magnet 20 and the second magnet 30 is 6mm, as shown in fig. 5, the output potential of the linear hall sensor 10 and the relative displacement between the linear hall sensor 10 and the first magnet 20 and the second magnet 30 are in an approximately sinusoidal relationship. Therefore, when the distance D between the first magnet 20 and the second magnet 30 is 6mm, the height H of the linear hall sensor 10 from the central line of the first magnet 20 and the second magnet 30 is preferably 4.5 mm.

Further, the linear hall sensor 10 moves between the first magnet 20 and the second magnet 30, that is, the moving range of the linear hall sensor 10 is the distance D between the first magnet 20 and the second magnet 30, that is, the central connecting line region of the first magnet 20 and the second magnet 30. More specifically, a height H of the first magnet 20 directly above the second magnet forms a first limit of the linear hall sensor 10, a height H of the second magnet 30 directly above the first magnet forms a second limit of the linear hall sensor 10, a line between the first limit and the second limit is parallel to a central line between the first magnet 20 and the second magnet 30, and a line between the first limit and the second limit is a moving range of the linear hall sensor 10. Vertical component B of magnetic induction B at height H_⊥The linear displacement high-precision measuring device linearly changes between the first limit and the second limit, so that the linearity of the linear displacement high-precision measuring device is as high as more than 0.9995 when the linear Hall sensor 10 moves between the first limit and the second limit.

The application also provides a sewing machine, wherein the sewing machine is provided with the above linear displacement high-precision measuring device. In the sewing machine, a linear displacement high-precision measuring device is used as a sewing machine presser foot height sensor and is used for measuring the presser foot height of the sewing machine, the measuring range is within 7mm, and the precision is far higher than 0.1 mm; alternatively, the linear displacement high-precision measuring device is used as a short-stroke position sensor, such as a voice coil motor position sensor; or the linear displacement high-precision measuring device is used as an electronic knee rest sensor and is used for measuring the displacement generated during knee rest, and the output signal of the linear displacement high-precision measuring device is approximately proportional to the rotating angle of the knee rest, so that the electronic knee rest pressure raising is realized.

In conclusion, the high-precision linear displacement measuring device is low in cost, simple in structure, easy to realize, resistant to oil contamination and dust pollution and high in measuring precision. Therefore, the invention effectively overcomes various defects in the prior art and has high industrial utilization value.

The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.