A Variable Flux Type Speed Sensor with a Composite Soft Magnetic Core

Abstract

The present invention discloses a variable flux speed sensor with a composite soft magnetic core, comprising a gear assembly and a speed sensor assembly. The gear assembly is rotated by an external drive source, and the speed sensor assembly is disposed on a radial side of the gear assembly. The speed sensor assembly also comprises a composite soft magnetic core, a coil, and a permanent magnet. The permanent magnet is disposed at the right end of the composite soft magnetic core, and the left end face of the composite soft magnetic core is flush with the serrations of the gear assembly. The coil surrounds the outside of the composite soft magnetic core. The rotation of the serrations periodically disturbs the magnetic field established in the composite soft magnetic core by the permanent magnet, thereby inducing a periodic induced voltage in the coil. The composite soft magnetic core of this device utilizes a main soft magnetic core and an auxiliary soft magnetic core in combination. This is achieved by utilizing the variable cross-section characteristics of the auxiliary soft magnetic core, which has superior performance, to increase the product's output voltage, facilitate signal acquisition by the collector, and reduce the product's internal resistance, thereby improving the product's load capacity.

Description

Technical Field

[0001] The invention belongs to the technical field, and in particular relates to a variable magnetic flux speed sensor with a composite soft magnetic core. Background Art

[0002] like Figure 1 The figure shows a traditional variable flux speed sensor and its application scenario. On the left is a rotating target. When the tooth tops and tooth grooves of the gear 601 pass through the soft magnetic core 602 of the variable flux speed sensor in sequence, the magnetic flux of the soft magnetic core 602 changes, thereby inducing a periodic voltage signal in the coil wound around the soft magnetic core 602. The speed of the target gear can be obtained by detecting this AC signal. At the same time, Figure 1 As shown in the figure, the cylinder defined by dimensions ΦA and ΦB should be small, resulting in a high output signal voltage and strong load capacity. The cross-section of the soft magnetic core is uniform at all points along the line connecting the gear to the permanent magnet, meaning the core is a cylinder with a diameter of ΦC. This structure is not conducive to further improving the sensor signal.

[0003] Patent No. 202111124988.9 discloses a variable flux speed sensor with a variable cross-section soft magnetic core. Although some improvements have been made to the existing technology, namely, the variable cross-section soft magnetic core has been optimized, this structure, due to the variable cross-section of the core, also results in a variable cross-section in the coil hole, which is not conducive to production. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the object of the present invention is to provide a variable flux speed sensor with a composite soft magnetic core, which solves the above-mentioned technical problems existing in the prior art.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A variable flux speed sensor with a composite soft magnetic core includes a gear assembly and a speed sensor assembly. The gear assembly is rotated by an external driving source.

[0007] The speed sensor assembly is arranged on a radial side of the gear assembly, and the speed sensor assembly includes a composite soft magnetic core, a coil and a permanent magnet. The permanent magnet is arranged at the right end of the composite soft magnetic core, the left end surface of the composite soft magnetic core is flush with the saw teeth of the gear assembly, and the coil is wrapped around the outside of the composite soft magnetic core;

[0008] The composite soft magnetic core includes a main soft magnetic core and an auxiliary soft magnetic core, wherein the geometric center of gravity of the auxiliary soft magnetic core is located between the gear assembly and the permanent magnet and close to one side of the permanent magnet, and the main soft magnetic core and the outer wall where the auxiliary soft magnetic core is located are formed into an integral whole, and the magnetic properties of the auxiliary soft magnetic core are superior to those of the main soft magnetic core;

[0009] The rotation of the saw teeth periodically disturbs the magnetic field created by the permanent magnet in the composite soft magnetic core, thereby inducing a periodic induced voltage in the coil, and at the same time outputs the generated periodic electrical signal to the outside through the coil.

[0010] Furthermore, the cross-sectional area of the right end portion where the attached soft magnetic core is located is not less than the cross-sectional area of the left end portion.

[0011] Furthermore, the soft magnetic core is connected in a multi-stage stepped manner, and the cross-sectional area on the side of the gear assembly is smaller than the cross-sectional area on the side of the permanent magnet.

[0012] Furthermore, the outer diameter of the auxiliary soft magnetic core is the same as the outer diameter of the main soft magnetic core, and the main soft magnetic core is located on a side of the auxiliary soft magnetic core close to the gear assembly.

[0013] Furthermore, the outer diameter of the auxiliary soft magnetic core is smaller than the outer diameter of the main soft magnetic core, and the main soft magnetic core surrounds the outer side of the auxiliary soft magnetic core, and the auxiliary soft magnetic core is arranged close to the permanent magnet.

[0014] Furthermore, the coil is fitted around the outer wall of the composite soft magnetic core.

[0015] Beneficial effects of the present invention:

[0016] 1. The device's composite soft magnetic core combines a main soft magnetic core with an auxiliary soft magnetic core. The auxiliary soft magnetic core's geometric center of gravity is located farther from the gears and closer to the permanent magnets, resulting in superior magnetic properties. This superior magnetic performance is achieved through the variable cross-section of the auxiliary soft magnetic core, enabling higher electrical signal output and increased output voltage for easier signal acquisition by the collector. It also reduces the product's internal resistance and improves its load capacity.

[0017] 2. Since the magnetic properties of soft magnetic materials and the processability of material processing and assembly (welding, etc.) cannot usually combine all the advantages in one device, the processability of the product can be improved by adopting a composite method.

[0018] 3. This device uses only the soft magnetic core with higher magnetic performance material, so that the composite soft magnetic core does not use all the cores with higher magnetic performance, which can reduce the total material cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for describing the embodiments or the prior art.

[0020] Figure 1 This is a schematic diagram of the overall structure of a variable flux speed sensor in the prior art;

[0021] Figure 2 This is a schematic diagram of the overall structure of Example 1 of the present invention;

[0022] Figure 3 This is a schematic diagram of the overall structure of Example 2 of the present invention;

[0023] Figure 4 1 is a schematic diagram of the overall structure of Example 3 of the present invention;

[0024] Figure 5 is a schematic diagram of the overall structure of Example 4 of the present invention;

[0025] Figure 6 is a schematic diagram of the overall structure of Example 5 of the present invention;

[0026] Figure 7 It is a graph data diagram of the output signal of a variable flux speed sensor in the prior art;

[0027] Figure 8 This is an output signal chart data diagram of Example 5 of the present invention. DETAILED DESCRIPTION

[0028] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0029] Example 1:

[0030] like Figure 2 As shown, a variable flux speed sensor with a composite soft magnetic core includes a gear assembly 1 and a speed sensor assembly 2. The gear assembly 1 is rotated by an external driving source.

[0031] The speed sensor assembly 2 is arranged on the radial side of the gear assembly 1. At the same time, the speed sensor assembly 2 includes a composite soft magnetic core 21, a coil 22 and a permanent magnet 23. The permanent magnet 23 is arranged at the right end of the composite soft magnetic core 21. The left end face of the composite soft magnetic core 21 is flush with the sawtooth 11 of the gear assembly 1, and the coil 22 is wrapped around the outside of the composite soft magnetic core 21.

[0032] The rotation of the saw teeth 11 periodically disturbs the magnetic field established by the permanent magnet 23 in the composite soft magnetic core 21, thereby inducing a periodic induced voltage in the coil 22, and at the same time outputting the generated periodic electrical signal to the outside through the coil 22. The composite soft magnetic core 21 includes a main soft magnetic core 211 and an auxiliary soft magnetic core 212. The cross-sectional area of the right end of the auxiliary soft magnetic core 212 is larger than the cross-sectional area of the left end (similar to a conical structure), so that the geometric center of gravity of the auxiliary soft magnetic core 212 is located between the gear assembly 1 and the permanent magnet 23 and close to one side of the permanent magnet 23, and the main soft magnetic core 211 and the outer wall of the auxiliary soft magnetic core 212 are formed as a whole (i.e., the cross-sectional area on the left and right sides is the same). The magnetic properties of the auxiliary soft magnetic core 212 are better than those of the main soft magnetic core 211. The coil 22 surrounds the outer wall of the composite soft magnetic core 21.

[0033] The composite soft magnetic core 21 is made of a composite material. The main soft magnetic core 211 uses a soft magnetic material with better processability, and the auxiliary soft magnetic core 212 uses a soft magnetic material with better magnetic properties. The geometric center of gravity of the auxiliary soft magnetic core 212 is located at a position away from the gear 11 and closer to the permanent magnet (for example, the tip of the cone or pyramid is facing the sawtooth 11, and the bottom of the cone or pyramid is away from the sawtooth 11). Compared with the solution used in the prior art, its performance is stronger.

[0034] Example 2: Figure 3 As shown, the auxiliary soft magnetic core 212 is configured as a truncated cone or a prism-shaped structure (it can be configured as a prism-shaped structure as needed, even if the cross-sectional area on the left side facing the permanent magnet is smaller than the cross-sectional area on the right side facing the sawtooth. The shape of the cross-section can be set according to actual conditions, all within the scope of protection of this application), and a method similar to that of Example 1 is adopted to form an integral body with the outer wall where the main soft magnetic core 211 and the auxiliary soft magnetic core 212 are located, so that the geometric center of gravity of the auxiliary soft magnetic core 212 is located away from the center of gravity of the gear 11 and close to the permanent magnet 23, all within the scope of protection of this application. Wherein ΦC is the diameter width of the composite soft magnetic core 21, and ΦD is the diameter width of the surrounding coil (the same below).

[0035] Example 3:

[0036] like Figure 4 As shown, the auxiliary soft magnetic core 212 is connected in a multi-stage stepped manner, that is, the cross-sectional area on the side of the gear assembly 1 is smaller than the cross-sectional area on the side of the permanent magnet 23, forming an effect of increasing the cross-sectional area to the right, and forming the main soft magnetic core 211 and the outer wall where the auxiliary soft magnetic core 212 is located into a whole.

[0037] Example 4:

[0038] like Figure 5As shown, the outer diameter of the attached soft magnetic core 212 is the same as the outer diameter of the main soft magnetic core 211, and the main soft magnetic core 211 is connected to the same cross section at the left end of the attached soft magnetic core 212. At this time, the geometric center of gravity of the attached soft magnetic core 212 is located away from the center of gravity of the gear 11 and close to the permanent magnet 23.

[0039] Example 5:

[0040] like Figure 6 As shown, the outer diameter of the auxiliary soft magnetic core 212 is smaller than the outer diameter of the main soft magnetic core 211 , and the main soft magnetic core 211 surrounds the outer side of the auxiliary soft magnetic core 212 .

[0041] like Figure 7 、 Figure 8 As shown in the figure, the output signal chart data before and after optimization using this patent are respectively shown under the same other conditions. It can be seen from the figure that at point m1 of the output curve (i.e. time 300 microseconds), the voltage peak value generated by the prior art is 10.8695, while the voltage peak value of Example 5 can reach 13.0637, that is, the output voltage of the product is increased by 19%.

[0042] Since the outer diameter of the composite soft magnetic core 21 of the present application remains the same on both sides, the requirements for the coil are not high. The inner hole shape of the coil surrounding the outside can be simplified to a circular hole. At the same time, only the attached soft magnetic core 212 is set to have a higher magnetic performance, so that the composite soft magnetic core 21 does not use an iron core with higher magnetic performance, which can reduce the total material cost. Since the magnetic properties of soft magnetic materials and the processability of material processing and assembly (welding, etc.) cannot usually be fully integrated, the processability of the product can be improved by adopting a composite method.

[0043] The sensor provided in this application is compact, lightweight, and delivers a strong signal. In addition to reducing coil resistance and increasing the sensor's load capacity, this solution also optimizes the magnetic field distribution of the core, increasing the product's output voltage by 19%, facilitating signal acquisition, and reducing the product's internal resistance, thereby increasing its load capacity.

[0044] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention, and such changes and modifications fall within the scope of the invention as claimed.

Claims

1. A variable flux speed sensor with a composite soft magnetic core, comprising a gear assembly (1) and a speed sensor assembly (2), wherein the gear assembly (1) is rotated by an external driving source, and is characterized in that: The speed sensor assembly (2) is arranged on a radial side of the gear assembly (1), and the speed sensor assembly (2) comprises a composite soft magnetic core (21), a coil (22) and a permanent magnet (23), wherein the permanent magnet (23) is arranged at the right end of the composite soft magnetic core (21), the left end of the composite soft magnetic core (21) is flush with the saw teeth (11) of the gear assembly (1), and the coil (22) surrounds the outside of the composite soft magnetic core (21); The composite soft magnetic core (21) comprises a main soft magnetic core (211) and an auxiliary soft magnetic core (212); the geometric center of gravity of the auxiliary soft magnetic core (212) is located between the gear assembly (1) and the permanent magnet (23) and close to one side of the permanent magnet (23); and the outer wall where the main soft magnetic core (211) and the auxiliary soft magnetic core (212) are located forms an integral whole; the magnetic properties of the auxiliary soft magnetic core (212) are superior to those of the main soft magnetic core (211); The rotation of the saw teeth (11) periodically disturbs the magnetic field established by the permanent magnet (23) in the composite soft magnetic core (21), thereby inducing a periodic induced voltage in the coil (22), and simultaneously outputting the generated periodic electrical signal to the outside through the coil (22).

2. The variable flux speed sensor of composite soft magnetic core according to claim 1, characterized in that: The cross-sectional area of the right end portion where the soft magnetic core (212) is located is not less than the cross-sectional area of the left end portion.

3. The variable flux speed sensor of the composite soft magnetic core according to claim 2, characterized in that: The soft magnetic core (212) is connected in a multi-stage stepped manner, and the cross-sectional area on the side of the gear assembly (1) is smaller than the cross-sectional area on the side of the permanent magnet (23).

4. The variable flux speed sensor of composite soft magnetic core according to claim 1, characterized in that: The outer diameter of the auxiliary soft magnetic core (212) is the same as the outer diameter of the main soft magnetic core (211), and the main soft magnetic core (211) is located on a side of the auxiliary soft magnetic core (212) close to the gear assembly (1).

5. The variable flux speed sensor of composite soft magnetic core according to claim 1, characterized in that: The outer diameter of the auxiliary soft magnetic core (212) is smaller than the outer diameter of the main soft magnetic core (211), and the main soft magnetic core (211) surrounds the outer side of the auxiliary soft magnetic core (212), and the auxiliary soft magnetic core (212) is located on one side of the permanent magnet (23).

6. The variable flux speed sensor of the composite soft magnetic core according to any one of claims 2 to 5, characterized in that: The coil (22) surrounds the outer wall where the composite soft magnetic core (21) is located.

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