Anti-interference differential lock position sensor

Abstract

The utility model relates to a sensor structure. An anti-interference differential lock position sensor comprises an induction disc connected with a differential lock, an eddy current sensor is installed outside the induction disc, the eddy current sensor comprises a PCBA board, an excitation coil and an induction coil are arranged on the PCBA board, the PCBA board is located on the outer side of the outer circumferential surface of the induction disc in the radial direction, and the induction coil is located on the outer side of the induction disc in the radial direction. The air gap between the PCBA board and the induction disc is not changed, and when the induction disc moves axially, the circumferential side face of the induction disc can cover and shield the coil on the PCBA board. The utility model provides the anti-interference differential lock position sensor which is high in linearity precision, strong in anti-interference capability and simple in structure; the technical problems that in the prior art, a position sensor applied to a differential locking position is poor in linear precision and poor in anti-interference capacity are solved.

Description

TECHNICAL FIELD

[0001] The utility model relates to a sensor structure especially relates to an anti -interference differential lock position sensor. BACKGROUND

[0002] In modern society, the car has become one of the public's first choice of transportation. Among them more and more vehicles are equipped with differential. Differential is composed of planetary gear, planetary carrier (differential case), axle gear and other parts. The power of engine enters differential through transmission shaft, directly drives planetary carrier, and then drives left and right two axle shafts by planetary gear, respectively drives left and right wheels. The working principle of differential is to adjust the speed difference of two sides of the wheel, to ensure that the inside wheel and the outside wheel can rotate at the appropriate speed when turning, so as to complete the turning action smoothly, and enhance the stability of the vehicle. But when one side of the vehicle wheel sinks into sand or mud, due to the low adhesion of the tire, serious skidding will occur, at this time the intervention of differential lock is needed, when we lock the differential lock, the planetary gear no longer rotates around the shaft, and the left and right axle gear forms a rigid connection, at this time the left and right wheels can output the same speed. Under this condition, because the speed of the two sides of the wheel is synchronous, the wheel with good adhesion can drive the vehicle to realize effective escape. The opening and closing stroke of differential lock is mostly recognized by hall sensor. Since the signal disc is a rotating target around the shaft, it is difficult to arrange the magnet on the target wheel, so the magnet is usually arranged in the sensor, and the signal disc material is set as ferromagnetic material. The sensor is installed axially to the signal disc. When the stroke changes, the magnetic flux intensity sensed by the chip also changes, so as to identify the specific stroke through calibration. But this detection method has many shortcomings: 1, the hall principle is greatly affected by magnetic field interference, especially the differential lock has an electromagnet, which seriously affects the magnetic field recognition of the hall sensor; 2, because the magnet in the sensor is small, when the stroke changes to a certain amplitude, the magnetic flux intensity sensed by the chip hardly changes, so the detection stroke is short; 3, because the change of air gap changes the magnetic flux intensity sensed by the chip, which is not linear, but similar to exponential curve, and generally this kind of hall chip can only support two point calibration, so the linearity precision is poor. SUMMARY

[0003] The utility model provides a linear degree precision high, anti -interference ability strong, simple structure's anti -interference differential lock position sensor, solve the technical problem that the linear precision of position sensor for application in differential lock position is poor and the anti -interference ability is not strong in prior art.

[0004] The technical problem of the above-mentioned utility model is solved through the following technical scheme: an anti-interference differential lock position sensor, which comprises a sensing disc connected with a differential lock, a vortex current sensor is installed outside the sensing disc, the vortex current sensor comprises a PCBA board, an exciting coil and an inductive coil are arranged on the PCBA board, the PCBA board is located outside the radial direction of the outer circumferential surface of the sensing disc, the air gap between the PCBA board and the sensing disc is invariable, when the sensing disc axially shifts, the circumferential side surface of the sensing disc will cover and shield the coil on the PCBA board. The core component of the sensor is the PCBA, the PCBA is provided with specially designed exciting coils and inductive coils, and a processing chip and its capacitor and resistor are attached to the patch, the chip will exert a high-frequency exciting signal on the exciting coil, at this time, the inductive coil will sense a corresponding electric signal, but when the coil is shielded by metal, for example, the side surface of the sensing disc, the surface of the sensing disc will be shielded by the exciting coil to sense eddy current, the eddy current generates a signal opposite to the inductive coil to offset, so that finally only the signal of the inductive coil which is not shielded can be output, when the sensing disc rotates around the shaft, the shielding surface does not change significantly, so the signal is invariable, but when the sensing disc axially shifts, the shielded part changes significantly, due to the existence of the inductive coil, a linear output signal relative to the axial displacement can be output through calibration, so that the axial shift can be accurately identified.

[0005] Preferably, the sensing disc is a metal disc, and an electromagnet is installed on one side of the sensing disc. The sensing disc is a metal component and is connected with the meshing gear of the differential lock, and the back surface is an electromagnet which generates a strong magnetic field when started to attract the sensing disc to move leftward to lock the differential lock; when the electromagnet is turned off, the magnetic field disappears, and the sensing disc moves rightward under the action of the reset spring to make the differential lock disengage. The electromagnet is convenient to operate and has strong suction force, and the strong magnetic source of the electromagnet can be avoided due to the adoption of the vortex current sensor.

[0006] Preferably, the air gap between the sensing disc and the sensing disc of the sensor is 0.8mm-1.2mm. The invariable air gap can improve the linearity precision.

[0007] Preferably, the sensor comprises a plastic shell, the PCBA board is filled in the plastic shell, the chip is installed on the PCBA board, the wiring terminal and the bushing are formed at one end of the plastic shell, and the plastic shell is located outside the radial direction of the sensing disc. The sensor is externally provided with a plastic shell, the metal bushing and the plug terminal are integrally formed through the insert injection molding forming process, then a PCBA is installed in the shell, the plug terminal is tin soldered, then the PCBA is filled with glue to be packaged, and finally the sealing ring is installed on the shell. The process is simple, and the installation and formation are convenient.

[0008] Therefore, the anti-interference differential lock position sensor has the following advantages:

[0009] 1. The sensor is designed based on the principle of eddy current induction, which is basically not affected by magnetic field and can be directly arranged near strong magnetic sources such as electromagnets;

[0010] 2. No additional magnet is needed, which reduces cost and facilitates sensor arrangement;

[0011] 3. The sensing stroke can be customized according to actual customer requirements, and there is no distance limit in theory;

[0012] 4. Due to the existence of the induction coil, the linearity of the stroke and the output signal can be guaranteed, thereby improving the precision. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 It is a perspective view of an anti-interference differential lock position sensor.

[0014] Figure 2 It is a side view of Figure 1 .

[0015] Figure 3 It is an exploded view of the sensor of Figure 1 .

[0016] Figure 4 It is a schematic view on the PCBA board. DETAILED DESCRIPTION

[0017] The technical scheme of the utility model will be further specifically explained below through examples and in combination with the drawings.

[0018] Example:

[0019] As shown in Figure 1 and 2 , an anti-interference differential lock position sensor includes a disc-shaped metal induction disc 1 connected with the meshing gear of the differential lock. An electromagnet 2 is installed on one side of the induction disc 1 in the axial direction. A eddy current sensor 3 is installed on the outside of the induction disc 1 in the radial direction. There is about 1mm air gap between the induction surface of the sensor and the induction disc. The induction disc 1 can move axially, but since the eddy current sensor 3 is located outside the induction disc, the air gap between the induction surface of the sensor and the induction disc will not change when the induction disc 1 moves axially. The length of the axial movement stroke H of the induction disc 1 is about 4mm.

[0020] As shown in Figure 3 and 4As shown, the eddy current sensor 3 comprises a plastic shell 4, a metal bushing 8 and a connector terminal 9 are integrally molded by insert injection molding process, then the PCBA board 5 is installed in the cavity of the plastic shell 4, the PCBA board 5 is formed with an excitation coil 15 and an induction coil 14. At the same time, the end of the PCBA board 5 is designed with a power pad 11, a ground pad 12 and a signal pad 13, which are connected with the connector terminal 9 by soldering, then the PCBA board 5 is encapsulated by potting glue 7, and finally the sealing ring 10 is installed on the plastic shell.

[0021] In use, the excitation coil 15 and the induction coil 14 designed on the PCBA, as well as the patch with processing chip 6 and its capacitor resistance, the chip 6 will apply a high-frequency excitation signal to the excitation coil, at this time the induction coil will induce a corresponding electric signal, but when the coil is blocked below by metal, such as the side of the induction disc, the surface of the induction disc will be induced by the excitation coil to generate eddy current, which generates a signal opposite to the induction coil to offset, so the final output can only be the signal of the induction coil without being blocked. When the induction disc rotates around the axis, the blocked surface does not change significantly, so the signal does not change, but when the signal wheel axially translates, the blocked part changes significantly, and since the induction coil is specially designed, it can output a linear output signal relative to the axial displacement by calibration, thereby accurately identifying the axial translation.

[0022] The specific embodiments described herein merely exemplify the inventive concept. Those skilled in the art can make various modifications or supplements to the described specific embodiments or use similar ways to replace, but will not deviate from the spirit of the invention or exceed the scope defined by the appended claims.

Claims

1. An interference-resistant differential lock position sensor comprising an inductive disc connected to a differential lock, characterized in that: The eddy current sensor is mounted outside the sensing disc, and comprises a PCBA board on which an excitation coil and an induction coil are arranged, the PCBA board is located outside the radial direction of the outer circumferential surface of the sensing disc, the air gap between the PCBA board and the sensing disc is constant, and the circumferential side surface of the sensing disc covers and shields the coil on the PCBA board when the sensing disc axially displaces.

2. A tamper-resistant limited slip lock position sensor according to claim 1, wherein: The sensing disc is a metal disc, and an electromagnet is mounted on one side of the sensing disc.

3. A tamper-resistant differential lock position sensor according to claim 1 or 2, characterized in that: The air gap between the sensing disc of the sensor and the sensing disc is 0.8mm-1.2mm.

4. A tamper-resistant differential lock position sensor according to claim 1 or 2, characterized in that: The sensor comprises a plastic shell, the PCBA board is filled in the plastic shell, the chip is mounted on the PCBA board, the wiring terminal and the bushing are formed at one end of the plastic shell, and the plastic shell is located outside the radial direction of the sensing disc.

Images