41results about How to "Reduce magnetic interference" patented technology

The invention discloses a rigidity-adaptive three-degree-of-freedom low-frequency electromagnetic vibration isolator, and belongs to the technical field of precise vibration isolation. The rigidity-adaptive three-degree-of-freedom low-frequency electromagnetic vibration isolator comprises three sets of low-frequency electromagnetic vibration isolators formed by connecting rigidity-adaptive electromagnetic arrays and spiral springs in parallel. The spiral spring stably supports the load in a passive mode and effectively isolates vibration of middle and high frequency bands; the rigidity self-adaptive electromagnetic array generates high negative rigidity through a moving magnetic array and a fixed magnetic array which are composed of four columns of vertically magnetized equal-cross-section cubic permanent magnets, coil current is adjusted in real time through acceleration feedback, external excitation and load mass changes are responded, the negative rigidity is dynamically adjusted, and the requirement for three-degree-of-freedom near-full-band vibration isolation is met. The vibration isolator has adjustable low dynamic rigidity in the vertical and horizontal rotation freedom degrees, the vibration isolation frequency is low, the frequency band is wide, a super-quiet environment is provided for tip equipment, and the instrument precision is remarkably improved.

The utility model relates to an air cylinder device which comprises a cylinder body, a plurality of air cylinders and an air cylinder, a plurality of air cylinders are arranged in the cylinder body at intervals in the first direction, and each air cylinder extends in the second direction intersecting with the first direction; an air inlet hole and an air outlet hole are formed in the cylinder body, the air inlet hole is communicated with each cavity, and the air outlet hole is communicated with each cavity; a plurality of piston rods, wherein one piston rod is arranged in each cavity; the magnetic sensor assembly is arranged on the cylinder body and located on the side, in the first direction, of the multiple cavities. Therefore, on one hand, under the condition that the push-pull force is certain, the width of the cylinder body can be thinned; on the other hand, under the condition that the width is not changed, the push-pull force of the air cylinder device can be multiplied; and on the other hand, the two adjacent air cylinder devices can be reversely installed in a staggered mode, the magnetic interference problem of the adjacent air cylinder devices is reduced to the maximum extent, and the use performance of the air cylinder devices is improved.

The invention provides a low-magnetic-leakage excitation coil design method and device capable of generating a high-uniformity magnetic field, and belongs to the technical field of magnetic field control, and the method comprises the steps: determining the target magnetic induction intensity and the length of a target uniformity region; based on a pre-constructed two-dimensional distribution function of the uniform region length and the central magnetic field intensity, determining the size parameters of the low-magnetic-leakage excitation coil corresponding to the target magnetic induction intensity and the target uniform region length by using an interpolation method or a table look-up method; based on the size parameters and the condition that the magnetic moment of the low-magnetic-leakage excitation coil is zero, the ratio of the number of turns inside and outside the low-magnetic-leakage excitation coil is determined; based on the required target magnetic induction intensity and target uniform region length, the designed low-magnetic-flux-leakage excitation coil enables the system to be in a low-magnetic-flux-leakage state externally, magnetic interference to surrounding equipment is reduced, and the measurement precision is effectively improved.

The present invention belongs to the technical field of current transformers, and in particular, relates to a magnetic isolation design method for a current transformer and a current transformer, comprising the following steps: S1, fixing a transformer housing on an operating table by means of a fixing component, and marking the position and size of a magnetic isolation groove on the inner wall and the outer wall of the transformer housing respectively; S2, using a slotting component to respectively open magnetic isolation grooves on the inner wall and the outer wall of the transformer housing according to the marked position and size of the magnetic isolation groove; S3, filling the magnetic isolation groove with a non-magnetic material by means of a filling component, fitting a sealing gasket at the upper mouth of the magnetic isolation groove, and sealing the non-magnetic material in the magnetic isolation groove. By means of the magnetic isolation groove design method, the magnetic fields of the primary winding and the secondary winding inside the current transformer can be effectively isolated, the magnetic interference inside the current transformer can be reduced, and at the same time, the magnetic interference of the external magnetic field on the current transformer can be effectively isolated, thereby improving the measurement accuracy of the current transformer.

The present invention discloses a pan-tilt module and a camera module, which relate to the field of camera technology and solve the technical problem that the existing driving motor makes the camera susceptible to interference from an external magnetic field. The pan-tilt module includes a first bracket for mounting a lens module and a second bracket sleeved on the outside of the first bracket, a coil assembly is mounted on the first bracket, and a magnetic component arranged opposite to the coil assembly is mounted on the second bracket, and the magnetic component drives the lens module to move along the optical axis. The present invention arranges the coil assembly on the first bracket on which the lens module is mounted, and arranges the magnetic component on the second bracket. When the coil assembly is energized, since the coil assembly is located inside the magnetic component, the magnetic interference of the external magnetic field on the lens module can be reduced, and the magnetic component drives the coil assembly to drive the lens module to move; when the coil assembly is not energized, since the coil assembly does not generate a magnetic thrust, the magnetic interference of the external magnetic field on the lens module can be avoided.

The invention relates to a bipolar magnetic bar structure of a needle selector. Relates to the technical field of needle selectors. The device specifically comprises a first magnetic bar and a second magnetic bar which are arranged at an interval, a first coil arranged on the first magnetic bar, and a second coil arranged on the second magnetic bar, the first magnetic bar is magnetized to form an N pole, the second magnetic bar is magnetized to form an S pole, the electrified first coil demagnetizes the first magnetic bar, and the electrified second coil demagnetizes the second magnetic bar. The first magnetic bar is magnetized to form an N pole, the second magnetic bar is magnetized to form an S pole, and when the first magnetic bar and the second magnetic bar attract the corresponding spring needles at the same time, the spring needles conduct the first magnetic bar of the N pole and the second magnetic bar of the S pole, so that magnetic induction lines outside the first magnetic bar and the second magnetic bar are spread in the spring needles; therefore, the magnetic field interference with the surrounding magnetic bars can be reduced, the energy loss of magnetic induction lines can be reduced, the accuracy of needle selection is ensured, and the production efficiency is improved.

The utility model relates to a button cell. The button battery comprises a battery body, a counteracting part, a positive wire and a negative wire, the battery body comprises a cover body, a cylinder body and a battery cell, the edge of the cover body and the end of the cylinder body are in insulated connection to define a containing cavity, the edge of the cover body forms a sealing opening, and the battery cell is wound in the containing cavity in the preset rotating direction; the battery cell is provided with a positive pole lug, a negative pole lug and a negative pole extension section, the positive pole lug is connected with the cover body, and the negative pole lug is connected with the cylinder body. The counteracting part is arranged at the sealing position in the preset rotating direction, the rotating length of the counteracting part is equal to or larger than that of the negative electrode extension section, the current direction of the counteracting part is opposite to that of the negative electrode extension section, and the counteracting part is connected with the cover body. The positive wire is connected with the counteracting part, the negative wire is connected with the cylinder, the counteracting part is electrified to generate a counteracting magnetic field to weaken magnetic interference of the magnetic field generated by the negative extension section on surrounding electromagnetic sensitive devices, and the positive wire and the negative wire are electrically connected, so that the installation is convenient.

The utility model relates to a magnetron sputtering device. The magnetron sputtering device comprises a target tube; the magnetic bar penetrates through the inner cavity of the target tube; the two sides of the target tube are sleeved with the magnetic field shielding sleeves, the magnetic field shielding sleeves are located at the two ends of the magnetic bar, and the magnetic field shielding sleeves and the target tube are fixedly arranged; and the target material sleeves the target tube and is positioned between the magnetic field shielding sleeves on the two sides of the target tube. The utility model has the beneficial effects that the magnetic field shielding sleeve can shield crossed magnetic fields at the two ends of the magnetic bar, so that the two ends of the target material are not sputtered, the excessive etching at the two ends of the target material is reduced, and the utilization rate of the target material is improved; when the magnetic field shielding sleeve is arranged in a magnetic field, magnetic lines of force of the magnetic field can be effectively absorbed and redirected. By absorbing and guiding magnetic lines, the magnetic field shielding sleeve can reduce penetration of a magnetic field and weaken magnetic field interference to the surrounding environment.

The invention provides a semiconductor packaging structure and a manufacturing method thereof. The semiconductor packaging structure comprises the components of a substrate which is provided with a first surface and a second surface which are oppositely arranged along the thickness direction of the substrate, the first surface is provided with a groove, the substrate is also internally provided with a first via hole, and the first via hole penetrates through the first surface and the second surface and is located at the side of the groove; the first shielding layer covers the bottom wall and the side wall of the groove; the chip is arranged in the groove, the chip is provided with a pin, and the pin is electrically connected with the first via hole; and the second shielding layer covers at least part of the surface, deviating from the bottom wall of the groove, of the chip. The semiconductor packaging structure is used for achieving the effect of improving magnetic shielding comprehensiveness and storage density.

In the magnetic field detection device capable of detecting the magnetic field along three axial directions, the magnetic interference among the magnetic sensors is reduced. A magnetic field detection device (100) is provided with a support body (10), and magnetic sensors (S1-S3) respectively housed in cutouts (121-123) of the support body (10). The cutout (121) is provided in at least one of the surfaces (11, 14) of the support body (10), the cutout (122) is provided in at least one of the surfaces (12, 15) of the support body (10), and the cutout (123) is provided in at least one of the surfaces (13, 16) of the support body (10). The magnetic sensor (S1) takes the X direction as the magnetic sensing direction, the magnetic sensor (S2) takes the Y direction as the magnetic sensing direction, and the magnetic sensor (S3) takes the Z direction as the magnetic sensing direction.

The application provides a motor, a camera module and an electronic device. The motor comprises a base, a first mover and a second mover. The first mover is used for carrying an optical path folding element, and the second mover is used for carrying a lens group. The motor drives the first mover to rotate relative to the base by a magnetic drive mode to realize optical anti-shake, and drives the second mover to displace relative to the base by the magnetic drive mode to realize optical focusing. The application designs the magnetic pole distribution of a magnetic stone in a magnetic drive structure for driving the first mover and the second mover to move, so as to reduce the interference of the magnetic drive magnetic field of the second mover on the movement of the first mover, thereby improving the stability of optical anti-shake and being beneficial to improving the shooting quality.

A stator coil of a rotating electric machine is formed by a concentric winding method. A stator coil is configured by inserting and connecting hairpin-shaped coil pieces (10, 11, 20, 21, 30, 31) formed from flat wires from one side and the other side in the axial direction. The length of the linear part of the coil piece is half of the axial length of the stator core, a convex shape or a concave shape is formed at the two leg end parts, and the convex part and the concave part are embedded. The coil is composed of three kinds of coil pieces: central coil pieces (10, 11) that connect the slots in the circumferential direction in the vicinity of the radial center of the slots; inner coil pieces (20, 21) that are connected in the circumferential direction so that coil end portions are biased inward in the radial direction than the radial positions of the slots; and outer coil pieces (30, 31) that are connected in the circumferential direction so as to be biased outward in the radial direction. Concentric coil portions formed by connected central coil pieces (10, 11), coil pieces (20, 31), and coil pieces (30, 21) are made to have the same length, so that the resistance values are made to be consistent, and the assemblability is improved.

The invention relates to a needle selector structure. Relates to the technical field of needle selectors. The needle selecting device specifically comprises a needle selecting seat, a plurality of magnetic rod assemblies fixedly installed on the needle selecting seat and a plurality of spring needles arranged above the magnetic rod assemblies, the magnetic rod assemblies are arranged on the needle selecting seat in a staggered mode, and the spring needles correspond to the magnetic rod assemblies one to one; the magnetic bar assembly comprises a first magnetic bar and a second magnetic bar which are arranged at intervals, the top end of the magnetized first magnetic bar is an N pole, and the top end of the magnetized second magnetic bar is an S pole. The top end of the first magnetic bar is N pole after being magnetized, the top end of the second magnetic bar is S pole after being magnetized, the top end of the first magnetic bar and the top end of the second magnetic bar are conducted through the spring needle, magnetic induction lines outside the first magnetic bar and the second magnetic bar are spread in the spring needle, and therefore magnetic field interference with surrounding magnetic bar assemblies can be reduced; and the energy loss of magnetic induction lines can be reduced, so that the needle selection accuracy is ensured, and the production efficiency is improved.

The invention discloses a saucer-shaped unmanned aerial vehicle aviation transient electromagnetic system and a parameter optimization method thereof, and the saucer-shaped unmanned aerial vehicle aviation transient electromagnetic system comprises a flying platform, and is characterized in that the outer side of the flying platform is provided with a transmitting coil which is located on the same horizontal plane with the flying platform; a compensating coil and a receiving sensor system are sequentially arranged below the flying platform; and the centers of the transmitting coil, the compensating coil and the receiving sensor system are positioned on the same straight line. The system has the beneficial effects that the wind resistance of the system is enhanced, background noise caused by asynchronous attitude change of the receiving sensing system and the flight platform is reduced, and the safety and high efficiency of full-aviation operation are realized. Meanwhile, through compensation parameter optimization, the compensation efficiency of the compensation coil is maximized, and the compensation coil counteracts the primary coupling influence of the transmitting coil, so that the magnetic field interference of the transmitting coil and the compensation coil on the flight control system and the receiving sensor system is minimum, and zero interference of the flight platform and the receiving sensor system is realized.

The embodiments of the present invention aim to provide an aperture module and a camera module including the aperture module that can reduce magnetic interference between the AF magnet and the ring magnet. By appropriately adjusting the magnetic pole positions of the AF magnet and the ring magnet, magnetic interference is reduced, making the drive of the aperture module smoother. The correlation between the number of magnetic poles of the AF magnet and the ring magnet can be utilized to ensure the diversity of the number or position of multiple coils, fixed shafts, and rolling components inside the aperture module by increasing the number of magnetic poles of the second magnet. This allows for more free design of the aperture module. Furthermore, two or more position sensors can be asymmetrically arranged according to the coil arrangement to more accurately measure the rotational displacement of the ring magnet. The thrust of the aperture module can also be adjusted by the size, number, and number of turns of the coils.

The invention relates to and discloses a magnetic bar assembly. Relates to the technical field of needle selectors. The device specifically comprises a magnetic bar base, a first magnetic bar, a second magnetic bar, a first coil arranged on the first magnetic bar, a second coil arranged on the second magnetic bar and a permanent magnet arranged between the first magnetic bar and the second magnetic bar, wherein the first magnetic bar and the second magnetic bar are arranged on the magnetic bar base at an interval; the N pole of the permanent magnet is attached to the first magnetic bar, the S pole of the permanent magnet is attached to the second magnetic bar, and the through-flow directions of the first coil and the second coil are opposite. The first magnetic bar, the permanent magnet and the second magnetic bar are regarded as an integral magnet, the first magnetic bar is the N pole of the magnet, the second magnetic bar is the S pole of the magnet, the N pole and the S pole of the magnet are conducted through the spring needle, and magnetic induction lines outside the magnet are spread in the spring needle, so that magnetic field interference between the magnet and surrounding magnetic bars can be reduced, and the magnetic field interference between the magnet and the surrounding magnetic bars can be reduced. And the energy loss of magnetic induction lines can be reduced, so that the needle selection accuracy is ensured, and the production efficiency is improved.

The invention relates to a glove machine capable of avoiding magnetic field interference. Relates to the technical field of glove machines. The device specifically comprises a needle selector and a needle plate assembly arranged above the needle selector, a plurality of magnetic bar assemblies are arranged in the needle selector, a plurality of spring needles in one-to-one correspondence with the magnetic bar assemblies are arranged in the needle plate assembly, each magnetic bar assembly comprises a first magnetic bar and a second magnetic bar which are arranged at intervals, the top end of the first magnetic bar is an N pole after the first magnetic bar is magnetized, and the top end of the second magnetic bar is an N pole after the second magnetic bar is magnetized. And the top end of the magnetized second magnetic bar is S-pole. The top end of the first magnetic bar of the magnetic bar assembly is N pole after being magnetized, the top end of the second magnetic bar is S pole after being magnetized, the top end of the first magnetic bar and the top end of the second magnetic bar are conducted through the spring needle, magnetic induction lines outside the first magnetic bar and the second magnetic bar are spread in the spring needle, and therefore magnetic field interference between the magnetic bar assembly and the surrounding magnetic bar assembly can be reduced; and the energy loss of magnetic induction lines can be reduced, so that the needle selection accuracy is ensured, and the production efficiency is improved.

The invention provides a small-sized fiber-optic gyroscope which comprises a light path part and a photoelectric information processing circuit part, and an integrated module is formed by selecting a mixed component U4 which integrates an FPGA (Field Programmable Gate Array), a D / A (Digital / Analog) conversion function and an A / D (Analog / Digital) conversion function; the optical path part is compactly distributed in the metal shell, and the polarization maintaining optical fiber ring is independently installed in the semi-cylindrical shielding cover adjacent to the metal shell and is isolated from other devices of the optical path part. According to the invention, a hybrid component integrating FPGA, D / A and A / D conversion functions is used for the first time, so that the size of a closed-loop control circuit is greatly reduced. According to the special-shaped small optical path structure designed by the invention, the optical path devices are compactly distributed in the metal shell, and the optical fiber ring is independently mounted in the semi-cylindrical shielding cover and is isolated from other optical devices, so that the magnetic interference of the optical fiber ring to other optical devices is reduced; meanwhile, noise caused by external environment fluctuation is effectively reduced, and the environmental adaptability of the fiber-optic gyroscope is improved.

The present invention belongs to the technical field of magnetic levitation motors, and discloses a bearingless motor, comprising a shell, wherein a motor stator is fixedly installed in the shell, end covers are fixedly installed at both ends of the shell, and the end covers seal and protect the internal structure of the shell, and a rotor is movably arranged in the middle of the motor stator, and the two ends of the rotor respectively penetrate the corresponding end covers, and the two ends of the rotor are rotatably connected to the end covers respectively; the motor stator comprises a drive winding and a control winding, and the iron cores of the drive winding and the control winding are fixedly connected as a whole; in the present invention, the drive winding and the control winding both have independent iron cores, which can avoid mutual interference between magnetic fields and improve the reliability of the motor.

The present embodiment relates to a lens driving device comprising: a housing; the substrate is arranged in the shell; the retainer is arranged in the shell; a magnet disposed on the holder; a coil interacting with the magnet; and an elastic member connecting the housing and the holder, in which the coil includes a first coil disposed on the substrate and a second coil disposed on an opposite side of the optical axis from the first coil, and the elastic member electrically connects the second coil and the substrate.

The invention discloses a double-shaft winding structure of a needle selector. Relates to the technical field of needle selectors. The winding specifically comprises a first spiral winding and a second spiral winding, the first spiral winding is provided with a first winding shaft, the second spiral winding is provided with a second winding shaft, and at least part of the first winding shaft and at least part of the second winding shaft are arranged in parallel at intervals; the through-flow directions of the first spiral winding and the second spiral winding are opposite, the electrified first spiral winding demagnetizes the first winding shaft, and the electrified second spiral winding demagnetizes the second winding shaft. The top end of the first winding shaft is N pole after the first winding shaft is magnetized, the top end of the first winding shaft is S pole after the first winding shaft is magnetized, and when the first winding shaft and the second winding shaft attract the spring needle, the spring needle conducts the first winding shaft and the second winding shaft, so that magnetic induction lines outside the first winding shaft and the second winding shaft are spread in the spring needle; therefore, the magnetic field interference with the surrounding magnetic bars can be reduced, the energy loss of magnetic induction lines can be reduced, the accuracy of needle selection is ensured, and the production efficiency is improved.

The present application provides a camera device and an electronic device, which relate to the technical field of camera devices. The camera device comprises: a housing; a driving component, which is arranged in the housing; a lens component, which is connected to the driving component; an optical resonance component, which is arranged in the housing and the lens component and is used to detect the displacement of the lens component. The driving component performs a focusing action according to the displacement information of the lens component by the optical resonance component.

The utility model discloses a separating cable bridge stand capable of separating strong current and weak current, which relates to the field of cable bridge stands, and comprises a bearing bridge stand and a cover plate, the inner surface of the bottom of the bearing bridge stand is fixedly provided with a separating plate, and the inner surface of the bearing bridge stand is embedded with a threaded connection seat; positioning type mounting assemblies are mounted on the side of the partition plate in a bilateral symmetry mode. According to the separated cable bridge capable of separating the strong current and the weak current, a guide sliding rod is arranged, so that a worker can drive a connecting plate to move left and right along the inner surface of the bearing bridge when driving a threaded adjusting rod to rotate in a threaded connecting seat; therefore, the cable can be quickly clamped and fixed between the movable bearing assembly and the positioning bearing assembly, so that the purpose of quickly installing the cable by the cable bridge is achieved. Therefore, the situation that the overall installation efficiency of the cable bridge is interfered due to the fact that a worker needs to spend a long time in cable installation work is avoided.

The invention discloses a printed circuit board Rogowski coil adjacent conductor interference resisting wire turn device and a design method. A boss of a printed circuit board forms a Rogowski coil by arranging wire turns; a third group of wire turns is arranged between the left boss and the right boss, and the winding direction of the third group of wire turns is opposite to that of the first group of wire turns; the winding direction of the third group of wire turns is the same as that of the second group of wire turns; the third group of wire turns comprises a first section of wire turn, a second section of wire turn and a third section of wire turn; the number of turns of the first section of wire turn is 1, the number of turns of the second section of wire turn and the number of turns of the third section of wire turn are equal and are both smaller than or equal to # imgabs0 #, and the second section of wire turn and the third section of wire turn are symmetrically arranged on the two sides of the first section of wire turn; wherein k is the number of turns of the first group of wire turns and is a positive odd number greater than or equal to 3; and during arrangement, the first section of wire turn is aligned with a circle of wire turn in the middle of the first group of wire turns. Mutual inductance between the adjacent conductors and the whole Rogowski coil is reduced, and therefore the Rogowski coil can resist interference of the adjacent conductors.

A slip ring assembly (300) includes: at least one first conductor group, and at least one second conductor group. Each first conductor group includes a first conductor (310) and a second conductor (320), and the first conductor (310) and the second conductor (320) are configured as annular structures, respectively. Each second conductor group includes a third conductor (330) and a fourth conductor (340), the third conductor (330) and the fourth conductor (340) are configured as annular structures, respectively. The first conductor (310), the second conductor (320), the third conductor (330) and the fourth conductor (340) are arranged to be apart from each other. A first current having a first phase and a first amplitude is configured to flow through the first conductor (310), a second current having a second phase and a second amplitude is configured to flow through the second conductor (320), a third current having a third phase and a third amplitude is configured to flow through the third conductor (330), and a fourth current having a fourth phase and a fourth amplitude is configured to flow through the fourth conductor (320).

The present invention relates to a lens driving device, a camera module including the lens driving device, and an optical apparatus. Embodiments include a substrate, a housing including first and second side portions facing each other and third and fourth side portions facing each other, a bobbin arranged inside the housing, a first coil arranged on the bobbin, and a magnet arranged in the housing, the substrate including a second coil facing the magnet, the magnet including a first magnet arranged on the first side portion of the housing, a second magnet arranged on the second side portion of the housing, and a third magnet arranged on the third side portion of the housing, the second coil including a first coil unit facing the first magnet, a second coil unit facing the second magnet, and a third coil unit facing the third magnet, the first to third coil units each including a wire having a plurality of turns, and the wire of the third coil unit is narrower in width than the wire of the first coil unit.

The utility model discloses a power supply signal female end connector, which comprises a first power supply module, a telecommunication module, a second power supply module and a positioning module, an inclined connecting section is arranged at one end, connected with a terminal main body part, of a terminal connecting part, and a material digging groove is arranged in the middle of the terminal connecting part. And the material digging groove extends towards the middle part of the terminal connecting part from the inclined connecting section. The arrangement of the anti-back structure can avoid the influence of reverse thrust caused by plug-in on the first power supply terminal and the second power supply terminal, and the anti-back effect is good. The positioning part ensures that the connector can be accurately plugged into an external plug, and the signal transmission is more stable. The width of the terminal connecting part is equal to the width of the terminal main body part, so that the strength of the signal terminal connecting part of the signal terminal is increased, the situation that the signal terminal connecting part is damaged when the signal terminals are inserted in a butt joint mode is avoided, and meanwhile magnetic field interference of the signal terminals on adjacent signal terminals in the signal transmission process is reduced.

The invention relates to a needle selection method of a glove knitting machine. Relates to the technical field of glove machines. The needle selector and the needle plate assembly are provided, a plurality of magnetic bar assemblies are arranged in the needle selector, a plurality of spring needles are arranged in the needle plate assembly, and each magnetic bar assembly comprises a magnetic part and an electrified coil; the target spring needle is attracted through the magnetic part, and a closed magnetic induction line is formed in the magnetic part and the target spring needle; the electrified coil is electrified to demagnetize the magnetic part, so that the magnetic part loosens the adsorbed target spring needle. One end of the magnetic part is the N pole, the other end of the magnetic part is the S pole, when the target spring needle is attracted through magnetic attraction force generated by the magnetic part, the N pole end and the S pole end of the magnetic part are conducted through the target spring needle, and therefore closed magnetic induction lines are formed in the magnetic part and the target spring needle, and magnetic field interference between the magnetic part and the surrounding magnetic rod assembly can be reduced; and the energy loss of magnetic induction lines can be reduced, so that the needle selection accuracy is ensured, and the production efficiency is improved.