Sensing device for rotary shaft

Abstract

A rotating shaft sensing device includes a first magnetostrictive strip, a second magnetostrictive strip, and a magnetic field sensor. The first and second magnetostrictive strips are arranged around the rotating shaft and rotate with it. The first magnetostrictive strip includes a plurality of first ribs and a plurality of first spacer grooves arranged at intervals. The second magnetostrictive strip includes a plurality of second ribs and a plurality of second spacer grooves arranged at intervals. The magnetic field sensor senses the magnetic field changes between the first and second magnetostrictive strips through the first ribs, the first spacer grooves, the second ribs, and the second spacer grooves to output the torque and / or rotational speed of the rotating shaft.

Claims

1. A rotating shaft sensing device for sensing a rotating shaft, the sensing device comprising: a first magnetostrictive strip, which is circumferentially disposed around the rotating shaft and rotates with the rotating shaft along a circumferential direction of the rotating shaft; the first magnetostrictive strip comprising a first connecting portion and a plurality of first ribs and a plurality of first spacer grooves arranged at intervals; one end of each of the first ribs being connected to the first connecting portion; the first ribs and the first spacer grooves being arranged in parallel; each of the first ribs having a first angle with the first connecting portion; each of the first spacer grooves being located between two adjacent first ribs; each of the first ribs having a first magnetic pole; the polarity of the first magnetic pole being selectable from an N pole or a S pole. A second magnetostrictive strip is encircled by the rotating shaft and rotates with the shaft. Along the circumferential direction, the second magnetostrictive strip includes a second connecting portion and a plurality of second ribs and a plurality of second spacer slots arranged at intervals. One end of each second rib is connected to the second connecting portion. The second ribs and the second spacer slots are arranged in parallel. The second ribs and the second connecting portion have a second included angle. A first included angle is the same as a first included angle. Each second spacer slot is located between two adjacent second ribs. Each second rib has a second magnetic pole, the polarity of which can be selected from the N pole or the S pole. Along an axial direction, there is a first gap between the first ribs and the second ribs. Along the axial direction, adjacent first ribs and second ribs form a plurality of V-shaped magnetic strain fields. A magnetic field sensing element senses the magnetic field change between the first magnetostrictive strip and the second magnetostrictive strip through the first ribs and the second ribs.

2. The rotating shaft sensing device of claim 1, further comprising a first magnetic element and a second magnetic element, the first magnetic element for magnetizing the first magnetostrictive strip to give the first ribs polarity, the second magnetic element for magnetizing the second magnetostrictive strip to give the second ribs polarity, the first magnetic element having a first magnet pole and a second magnet pole along the axial direction, the polarity of the first magnet pole being different from the polarity of the second magnet pole, the second magnetic element having a third magnet pole and a fourth magnet pole, the polarity of the third magnet pole being different from the polarity of the fourth magnet pole, the second magnet pole facing the third magnet pole, the first magnet pole of the first ribs, the second magnet pole of the second ribs, the second magnet pole of the first magnetic element, and the third magnet pole of the second magnetic element having the same polarity.

3. The rotating shaft sensing device of claim 1 or 2, wherein along the circumferential direction, the rotating shaft sensing device further includes a third magnetostrictive strip and a fourth magnetostrictive strip circumferentially disposed on the rotating shaft, the third magnetostrictive strip and the fourth magnetostrictive strip rotating with the rotating shaft, the third magnetostrictive strip adjacent to the first magnetostrictive strip along the circumferential direction, the fourth magnetostrictive strip adjacent to the second magnetostrictive strip, the third magnetostrictive strip and the first magnetostrictive strip surrounding the rotating shaft, the fourth magnetostrictive strip and the second magnetostrictive strip surrounding the rotating shaft, and along the circumferential direction, the third magnetostrictive strip includes a plurality of third ribs and a plurality of third spacer grooves spaced apart, each third spacer groove being located between two adjacent third ribs, the third ribs having The fourth magnetostrictive band has a third magnetic pole and includes a plurality of fourth ribs and a plurality of fourth spacer slots arranged at intervals. Each fourth spacer slot is located between two adjacent fourth ribs. Each fourth rib has a fourth magnetic pole. Along the axial direction, there is a second gap between the third ribs and the fourth ribs. Along the circumferential direction, the second gap connects to the first gap. The polarity of the first magnetic pole of each first rib is the same as the polarity of the second magnetic pole of each second rib. The polarity of the third magnetic pole of each third rib is the same as the polarity of the fourth magnetic pole of each fourth rib. The polarity of the third magnetic pole of each third rib and the polarity of the fourth magnetic pole of each fourth rib are different from the polarity of the first magnetic pole of each first rib and the polarity of the second magnetic pole of each second rib.

4. The rotating shaft sensing device as claimed in claim 3, further comprising a third magnetic element and a fourth magnetic element, the third magnetic element for magnetizing the third magnetostrictive strip to give the third ribs polarity, the fourth magnetic element for magnetizing the fourth magnetostrictive strip to give the fourth ribs polarity, along the axial direction, the third magnetic element having a fifth magnet pole and a sixth magnet pole, the polarity of the fifth magnet pole being different from the polarity of the sixth magnet pole, the fourth magnetic element having a seventh magnet pole and an eighth magnet pole, the polarity of the seventh magnet pole being different from the polarity of the eighth magnet pole, the sixth magnet pole facing the seventh magnet pole, the polarity of the sixth magnet pole being the same as the polarity of the seventh magnet pole, the polarity of the second magnet pole being different from the polarities of the sixth and seventh magnet poles, and the polarity of the third magnet pole being different from the polarities of the sixth and seventh magnet poles.

5. The shaft sensing device of claim 1, further comprising a first magnetic element and a second magnetic element, the first magnetic element for magnetizing the first ribs, the second magnetic element for magnetizing the second ribs, the first magnetic element having a first magnetic pole and a second magnetic pole along the axial direction, the polarity of the first magnetic pole being different from the polarity of the second magnetic pole, the second magnetic element having a third magnetic pole and a fourth magnetic pole, the polarity of the third magnetic pole being different from the polarity of the fourth magnetic pole, the second magnetic pole facing the third magnetic pole, the polarity of the second magnetic pole being different from the polarity of the third magnetic pole, the polarity of the second magnetic pole being the same as the polarity of the first magnetic pole of the first ribs, and the polarity of the first magnetic pole of the first ribs being different from the polarity of the second magnetic pole of the second ribs.

6. The shaft sensing device of claim 1 or 5, wherein along the circumferential direction, the shaft sensing device further includes a third magnetostrictive strip and a fourth magnetostrictive strip circumferentially disposed on the shaft, the third and fourth magnetostrictive strips rotating with the shaft, the third magnetostrictive strip adjacent to the first magnetostrictive strip along the circumferential direction, the fourth magnetostrictive strip adjacent to the second magnetostrictive strip, the third and first magnetostrictive strips surrounding the shaft, the fourth and second magnetostrictive strips surrounding the shaft, and along the circumferential direction, the third magnetostrictive strip includes a plurality of spaced-apart third ribs and a plurality of third spacer slots, each third spacer slot being located between two adjacent third ribs, the third ribs having a third magnetic pole, and the fourth magnetostrictive strip including a plurality of spaced-apart third ribs. A plurality of fourth ribs and a plurality of fourth spacer slots, each fourth spacer slot being located between two adjacent fourth ribs, each fourth rib having a fourth magnetic pole, a second gap being formed between the third ribs and the fourth ribs along an axial direction, the second gap connecting the first gap along the circumferential direction, the polarity of the first magnetic pole of the first ribs being different from the polarity of the second magnetic pole of the second ribs, the polarity of the third magnetic pole of the third ribs being different from the polarity of the fourth magnetic pole of the fourth ribs and the polarity of the first magnetic pole of the first ribs, the polarity of the fourth magnetic pole of the fourth ribs being different from the polarity of the second magnetic pole of the second ribs, the polarity of the first magnetic pole of the first ribs being the same as the polarity of the fourth magnetic pole of the fourth ribs, and the polarity of the second magnetic pole of the second ribs being the same as the polarity of the third magnetic pole of the third ribs.

7. The shaft sensing device of claim 6, further comprising a third magnetic element and a fourth magnetic element, the third magnetic element for magnetizing the third ribs, the fourth magnetic element for magnetizing the fourth ribs, the third magnetic element having a fifth magnetic pole and a sixth magnetic pole along the axial direction, the polarity of the fifth magnetic pole being different from the polarity of the sixth magnetic pole, the fourth magnetic element having a seventh magnetic pole and an eighth magnetic pole, the polarity of the seventh magnetic pole being different from the polarity of the eighth magnetic pole, the sixth magnetic pole facing the seventh magnetic pole, the polarity of the sixth magnetic pole being different from the polarity of the seventh magnetic pole, the polarity of the sixth magnetic pole being the same as the polarity of the third magnetic pole of the third ribs, the polarity of the second magnetic pole being the same as the polarity of the seventh magnetic pole, and the polarity of the third magnetic pole being the same as the polarity of the sixth magnetic pole.

8. The shaft sensing device of claim 1, wherein the magnetic field sensing element is located in the first gap between the first ribs and the second ribs.

9. The shaft sensing device of claim 1 or 8, wherein along the circumferential direction, the first gap exposes an annular groove of the shaft, and the magnetic field sensing element is located in the annular groove.

10. The shaft sensing device of claim 3, wherein along the circumferential direction, the first gap and the second gap expose an annular groove of the shaft, and the magnetic field sensing element is located in the annular groove.

11. The rotating shaft sensing device of claim 1, wherein a first width of each of the first ribs, a width of each of the first spacers, a width of each of the second ribs, and a second width of each of the second spacers are the same.

12. The rotating shaft sensing device of claim 1, wherein a first width of each of the first ribs, a second width of each of the first spacers, a third width of each of the second ribs and a fourth width of each of the second spacers are between 1 mm and 2.5 mm.

13. The rotating shaft sensing device of claim 1, wherein the thickness of the first magnetostrictive strip and the thickness of the second magnetostrictive strip are between 0.2 mm and 0.5 mm.

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