An arrayed magnetic field scanning sensor and a telescopic drive mechanism

Abstract

The utility model discloses an array formula magnetic field scanning sensor and telescopic drive mechanism, including magnetic gage and inductive magnetic head, a plurality of magnetic induction chips are distributed in the inductive magnetic head, at least one magnetic pole section is distributed on the magnetic gage, and the distribution length of each magnetic induction chip is greater than the distribution length of each magnetic pole section. Telescopic drive mechanism includes cylinder seat and reciprocating sliding installation piston rod in the cylinder seat, and the magnetic pole section is installed on the piston rod, and the inductive magnetic head is installed on the cylinder seat. The utility model has the beneficial effects that: solve how to realize the technical problem of full stroke measurement in the measurement scene that cannot be paved full magnetic gage.

Description

Technical Field

[0001] This utility model relates to a magnetic induction displacement encoder, specifically to an array-type magnetic field scanning sensor and a telescopic drive mechanism. Background Technology

[0002] Magnetic induction displacement encoders are widely used displacement measurement devices in industrial control, robotics, and other fields. They mainly consist of a magnetic grating and a magnetic head. The magnetic grating has magnetic blocks arranged in sequence, and the magnetic head has a built-in Hall effect magnetic sensing chip. The working principle is as follows: the magnetic grating and the magnetic head are fixedly mounted on two relatively moving devices. The magnetic head (containing a magnetic sensing element) is close to the magnetic grating, and when the two move relative to each other, the magnetic head senses the change in the magnetic signal and outputs analog signals such as sine / cosine. Subsequent circuitry then subdivides and decodes the analog signal, ultimately converting it into a digital signal representing displacement.

[0003] In traditional technologies, magnetic gratings typically cover the entire displacement measurement stroke. The chip inside the magnetic head moves relative to the grating to achieve full-stroke measurement. However, in some special scenarios, due to the unique structure of the object being measured, it is difficult to cover the entire measurement stroke with magnetic gratings, thus limiting the application of this type of displacement encoder. For example, in cylinders or hydraulic cylinders, when measuring the piston rod stroke, it is not convenient to cover the entire stroke with magnetic gratings between the cylinder body and the piston rod. Utility Model Content

[0004] In view of this, one of the objectives of this utility model is to provide an array-type magnetic field scanning sensor that can achieve full-stroke displacement measurement without covering the entire magnetic grating.

[0005] To achieve the above objectives, the technical solution of this utility model is as follows:

[0006] An array-type magnetic field scanning sensor includes a magnetic grating ruler and a sensing head. The key features are: multiple magnetic sensing chips are arrayed inside the sensing head, and at least one magnetic pole segment is distributed on the magnetic grating ruler. The distribution length of each magnetic sensing chip is greater than the distribution length of each magnetic pole segment.

[0007] Preferably, the magnetic grating ruler has at least two magnetic pole segments distributed on it, and the magnetic pole segments are spaced apart along the length direction of the magnetic grating ruler. Along the length direction of the magnetic grating ruler, there is a non-magnetic segment between any two adjacent magnetic pole segments, and within each non-magnetic segment, the width of any two adjacent non-magnetic segments is different.

[0008] Preferably, the magnetic pole segment is provided with at least one set of magnetic elements, and each set of magnetic elements includes "N" pole magnetic elements and "S" pole magnetic elements arranged along the length direction of the grid ruler body.

[0009] Preferably, the magnetic pole segment is provided with two, three, four or five sets of magnetic elements.

[0010] Preferably, in each of the non-magnetic segments, the width value gradually increases or decreases along the length direction of the grating body, or changes in an arithmetic sequence pattern.

[0011] Preferably, each of the magnetic induction chips is arranged in a linear array or an arc array within the induction head; and / or, the magnetic induction chip is a 2D or 3D Hall chip.

[0012] The second objective of this utility model is to provide a telescopic drive mechanism, including a cylinder seat and a piston rod that is reciprocally slidably installed in the cylinder seat. The key feature is that it also includes the above-mentioned array magnetic field scanning sensor, with the magnetic pole section installed on the piston rod and the sensing magnetic head installed on the cylinder seat.

[0013] Compared with the prior art, the beneficial effects of this utility model are:

[0014] 1. For measurement scenarios where it is impossible to cover the entire magnetic grating, since the distribution length of each magnetic induction chip is greater than the distribution length of each magnetic pole segment, the entire measurement stroke can be covered by the array of magnetic induction chips. When the magnetic grating ruler and the induction head move relative to each other, the array of magnetic induction chips can also detect alternately and connect the data to achieve full-stroke measurement. This solves the technical problem of how to achieve full-stroke measurement in measurement scenarios where it is impossible to cover the entire magnetic grating.

[0015] 2. In the magnetic scale, non-magnetic segments are arranged at intervals, and the width of any two adjacent non-magnetic segments is different. During the left and right movement of the induction head relative to the magnetic scale, the magnetic induction chip can cooperate with the entire magnetic scale to complete the absolute value positioning measurement. Therefore, by setting magnetic pole segments and non-magnetic segments at intervals, incremental displacement and absolute position measurement can be completed simultaneously on a single magnetic scale, which has the technical advantages of simple structure and high stability. Attached Figure Description

[0016] Figure 1 A schematic diagram of a magnetic grating ruler A with multiple magnetic pole segments 2.

[0017] Figure 2 This is a schematic diagram of the structure of the sensing head B.

[0018] Figure 3 This is a schematic diagram illustrating the principle of an array-type magnetic field scanning sensor applied to a cylinder.

[0019] Figure 4 This is a schematic diagram of the principle of an array-type magnetic field scanning sensor.

[0020] Figure 5This is a schematic diagram of a single magnetic grating ruler A with two sets of induction heads B distributed circumferentially. Detailed Implementation

[0021] This embodiment uses the application of an array-type magnetic field scanning sensor in a telescopic drive mechanism as an example for detailed explanation. In this embodiment, the telescopic drive mechanism is specifically a cylinder, but in actual application scenarios, it can also be a hydraulic cylinder or an electric cylinder.

[0022] like Figure 3 As shown, the telescopic drive mechanism is a cylinder, including a cylinder seat 5 and a piston rod 6 reciprocatingly sliding within the cylinder seat 5. An array-type magnetic field scanning sensor is installed inside the cylinder. The array-type magnetic field scanning sensor includes a magnetic grating A and a sensing head B. The magnetic grating A is mounted on the piston of the piston rod 6, and at least one magnetic pole segment 2 is distributed on the magnetic grating A. The sensing head B is mounted on the cylinder seat 5. (The last sentence appears to be incomplete and possibly refers to a different mechanism.) Figure 2 It can be seen that the induction head B has multiple magnetic induction chips 1 arranged in an array, and the specific array direction is parallel to the displacement direction.

[0023] Based on the above application, the distribution length of each magnetic induction chip 1 is greater than the distribution length of each magnetic pole segment 2. Furthermore, the arrayed magnetic induction chips 1 cover the entire sliding stroke of the cylinder. During the extension and retraction of the piston rod 6, the magnetic grating ruler A moves relative to the induction head B. The arrayed magnetic induction chips 1 alternately detect, allowing the data to be linked together, thus achieving full-stroke measurement of the piston rod. Therefore, the technical problem of how to achieve full-stroke measurement without completely covering the magnetic grating is solved.

[0024] For example Figure 3 The sensing head B is mounted on the outside of the cylinder base 5. A shielding layer 4 can also be provided on the side of the magnetic sensing chip 1 furthest from the magnetic grating ruler A. This shielding layer is fixed to the cylinder base, on the outer side. The shielding layer can be made of a highly magnetically permeable material such as silicon steel, iron, or nickel sheets. This prevents external magnetic fields from intruding into the sensor's sensing range, ensuring the magnetic field reaches the chip smoothly without interference from external magnetic fields. In addition, the shielding layer can cover the area of ​​the magnetic sensing chip 1 in a sheet shape, or it can be curved or tubular to increase the coverage area and achieve a complete shielding effect. The shielding layer mentioned here refers to magnetic field shielding, not electric field shielding. Using soft magnetic materials can also achieve the same magnetic field shielding effect.

[0025] In practical applications, a single magnetic pole segment 2 on the magnetic scale A is sufficient to meet measurement requirements. Of course, more magnetic pole segments 2 can be arrayed as needed to make the magnetic field more stable and improve measurement accuracy. Please refer to [the relevant documentation] for details. Figure 1As shown, the magnetic scale A has a long, strip-shaped scale body. The upper surface of the scale body is covered with alternating arrays of magnetic pole segments 2 and non-magnetic segments 3 along its length. When the induction head B moves left and right relative to the magnetic scale A, the magnetic induction chip 1 sequentially induces magnetic induction with each of the magnetic pole segments 2 arranged along the length of the scale body, thereby completing incremental displacement measurement. The specific principle of magnetic induction incremental ranging is a mature existing technology and will not be elaborated upon here.

[0026] In the magnetic grating ruler A of this embodiment, the widths of any two adjacent non-magnetic segments 3 are different. Based on this, please refer to... Figure 4 As shown, during the left-right movement of the sensing head B relative to the magnetic scale A, the magnetic induction chip 1 can cooperate with the entire magnetic scale A to complete absolute positioning measurement. Therefore, by setting regularly changing non-magnetic segments 3, it is possible to simultaneously complete incremental displacement and absolute position measurement on a single magnetic scale, which has the technical advantages of simple structure and high stability. The regularly changing aspect here specifically refers to the different width values ​​of two adjacent non-magnetic segments 3. For example, in each non-magnetic segment 3, its width value gradually increases or decreases, or exhibits other non-linear changes. The non-magnetic segment 3 specifically refers to a blank area where the scale body is not magnetized.

[0027] For example Figure 1 As shown, magnetic pole segment 2 consists of several groups of magnetic elements a. Each group of magnetic elements a includes one "N" pole magnetic element and one "S" pole magnetic element, which are arranged sequentially along the length of the scale body. Specifically, the number of groups of magnetic elements a can be one, two, three, four, or five, etc. When there is only one group, only basic measurement functions can be achieved. The more groups there are, the higher the measurement accuracy.

[0028] In this embodiment, please refer to Figure 1 Magnetic pole segment 2 is equipped with four sets of magnetic elements a, totaling eight single poles. The width of the "N" and "S" pole magnetic elements is 2 mm, and each magnetic pole segment 2 is 16 mm wide. In each non-magnetic segment 3, the first non-magnetic segment 3 is 1 mm wide, and the width of the remaining non-magnetic segments 3 increases by 0.1 mm each time, up to 10 mm. Based on this, there are a total of 91 magnetic pole segments 2 and 91 non-magnetic segments 3, with a total stroke of 1956.5 mm.

[0029] In practical applications, an array-type magnetic field scanning sensor can consist of a magnetic grating ruler A and multiple sets of inductive magnetic heads B, with each set of inductive magnetic heads B symmetrically arranged around the circumference of the magnetic grating ruler A. Please refer to the attached document. Figure 5As shown, the sensor includes two sets of sensing heads B and a magnetic scale A. The two sets of sensing heads B are symmetrically arranged 180° on opposite sides of the magnetic scale A. The technical value of this design lies in the fact that when the magnet of the magnetic scale A is misaligned or unevenly magnetized, an accurate value can be calculated using the displacement data from the chip board of the two sets of sensing heads B. Figure 5 As shown, the magnetic field has rotated and shifted. Line S represents the magnetic field magnetization boundary plane. This rotation and shift cause the data obtained by one set of induction heads B chip boards to increase, while the data obtained by the other set decreases. The two can be offset by averaging, still accurately determining the displacement value of the magnet along the array direction. Therefore, this layout can achieve accurate measurement values ​​even with imprecise magnets or imprecise magnet holding mechanisms. Specifically, in the cylinder piston structure provided in this embodiment, the magnetic grating ruler A is mounted on the piston in the form of a magnetic ring. An induction head B is arranged on each side of the cylinder, and the detection angle between the two induction heads B is 180 degrees, which can play a role in offset compensation. Even if the magnetic ring spins or shifts, accuracy can be guaranteed.

[0030] The array-type magnetic field scanning sensor provided in this embodiment differs from traditional magnetic position chips in that traditional magnetic position chips sense magnetic induction intensity in a single direction and calculate magnet displacement based on magnetic field strength. In this embodiment, the magnetic induction chip 1 is a 2D or 3D Hall chip. A 2D or 3D Hall chip integrates magnetic field induction value detection in two or three directions, and can calculate the direction of magnetic field lines using the CORDIC algorithm, which is more reliable than simply calculating the intensity value because intensity is related to the distance from the magnet, while the direction of magnetic field lines is minimally affected. The 2D or 3D Hall chip uses magnetic field strength along two orthogonal axes to calculate the direction of magnetic field lines; a 2D chip can detect two orthogonal axes, and a 3D chip can detect three. Multiple magnetic induction chips 1 are arrayed within the sensing head B; in actual products, this can be represented by the chips being arranged in an array on a PCB board.

[0031] Based on the above distinguishing characteristics, the specific implementation forms of array-type magnetic field scanning sensors can be: 1. Chips are arranged in an array on a PCB board, and the magnets are single magnets. 2. Chips are arranged in an array on a PCB board, and the magnets are also arranged in an array, performing a comprehensive magnetic field scan for more accurate positioning. 3. Chips are arranged in an array on a PCB board, and the magnets are also arranged in an array, with the magnet arrays grouped and spaced apart.

[0032] Finally, it should be noted that the above description is merely a preferred embodiment of the present utility model. Those skilled in the art, under the guidance of the present utility model, can make various similar representations without departing from the spirit and claims of the present utility model, and such modifications all fall within the protection scope of the present utility model.

Claims

1. An array-type magnetic field scanning sensor, comprising a magnetic grating ruler (A) and a sensing magnetic head (B), characterized in that: The induction head (B) has multiple magnetic induction chips (1) arranged in an array, and the magnetic grid ruler (A) has at least one magnetic pole segment (2) arranged on it. The length of each magnetic induction chip (1) is greater than the length of each magnetic pole segment (2).

2. The array-type magnetic field scanning sensor according to claim 1, characterized in that: The magnetic grating ruler (A) has at least two magnetic pole segments (2) distributed on it, and each magnetic pole segment (2) is spaced apart along the length direction of the magnetic grating ruler (A).

3. The array-type magnetic field scanning sensor according to claim 2, characterized in that: Along the length of the magnetic grating ruler (A), there is a non-magnetic segment (3) between two adjacent magnetic pole segments (2), and the width of any two adjacent non-magnetic segments (3) is different.

4. The array-type magnetic field scanning sensor according to claim 1, characterized in that: The magnetic induction chip (1) has a shielding layer (4) on the side away from the magnetic grid ruler (A).

5. The array-type magnetic field scanning sensor according to claim 4, characterized in that: The magnetic pole segment (2) is provided with at least one set of magnetic elements (a), each set of magnetic elements (a) including "N" pole magnetic elements and "S" pole magnetic elements arranged along the length direction of the grid ruler body.

6. The array-type magnetic field scanning sensor according to claim 5, characterized in that: The magnetic pole segment (2) is provided with two, three, four or five sets of magnetic elements (a).

7. The array-type magnetic field scanning sensor according to claim 3, characterized in that: In each of the non-magnetic segments (3), the width value gradually increases or decreases along the length of the grating body, or changes in an arithmetic sequence pattern.

8. The array-type magnetic field scanning sensor according to claim 1, characterized in that: The sensor includes at least two sets of sensing heads (B), each set of sensing heads (B) being symmetrically arranged around the magnetic scale (A).

9. The array-type magnetic field scanning sensor according to claim 1, characterized in that: Each of the magnetic induction chips (1) is arranged in a linear array or an arc array within the induction head (B); And / or, the magnetic induction chip (1) is a 2D or 3D Hall chip.

10. A telescopic drive mechanism, comprising a cylinder seat (5) and a piston rod (6) reciprocally slidingly mounted within the cylinder seat (5), characterized in that: It also includes an array magnetic field scanning sensor according to any one of claims 1 to 9, wherein the magnetic pole segment (2) is mounted on the piston rod (6) and the inductive magnetic head (B) is mounted on the cylinder seat (5).

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