KR20020066951A - Non-contact type rotary positioning sensor - Google Patents

Abstract

PURPOSE: A non-contact type rotary positioning sensor is provided to accurately measure the magnitude of magnetism caused by rotation by eliminating the imbalance of magnetism that occurs due to the eccentricity of the rotating body, by having one hall element sense the magnitude of magnetism detected by two sensing bars located in different positions. CONSTITUTION: A non-contact type rotary positioning sensor(1) includes a rotary shaft(10) with spline formed for joining with the object to be measured such as engine, motor frame or pedal, and a rotary shaft(10) is mounted on a housing(30) in a rotatable manner. The top of the housing(30) is covered with a cover(20), and the rear of housing(30) has a number of wires protruded. At the ends of these wires(74), terminals of various forms are inserted to be connected with connectors or wire harnesses. In the cover(20) are formed sensor mounting holes(22), which penetrate the housing(30) to couple the rotary positioning sensor(1) of the present invention with the object to be measured. At one end are formed adhesives injecting holes(26) for injecting adhesives such as silicone to prevent float of wires(74).

Description

Non-contact rotary displacement sensor {NON-CONTACT TYPE ROTARY POSITIONING SENSOR}

1. Field of invention

The present invention relates to a non-contact rotational displacement sensor, and more particularly, by detecting the magnitude of the magnetism detected by two sensing bars located at different points with one Hall element, which may occur due to the eccentricity of the rotating body. The present invention relates to a non-contact rotational displacement sensor capable of accurately measuring the magnitude of magnetism according to the rotation of a rotating body by eliminating magnetic imbalance.

2. Prior art in the field of invention

In general, the rotation displacement sensor is used to apply the physical variation of the rotating body continuously changing in the electrical circuit, the rotation position displacement sensor equipped with the electrical signal output function is used in various fields of the industry have. For example, it is used to control the opening amount of the engine throttle valve of the transportation vehicle, the control of the rotation angle of the steering shaft, the control of the electronic accelerator pedal, the position control of heavy equipment and agricultural machinery, and the opening and closing measurement of the fluid transfer valve.

Methods of measuring rotational displacement include potentiometric, coded disk shaft encoders, hall elements, magneto-resistive, and inductive sensing. In actual use, it can operate at -40 ℃ to + 70 ℃, which is required in harsh operating conditions such as commercial vehicles or heavy equipment, and it has durability of ± 5 million times of durability and ± minimum durability life required by environmental conditions such as dust and vibration. It should be able to maintain about 2%.

However, the electric resistance rotational displacement sensor is a resistance track processed on a ceramic substrate floating on the PCB substrate, and has disadvantages such as a change in electrical characteristics with temperature and a limitation of durability life and measurement accuracy due to brush wear.

For example, first, due to the wide variation of resistance characteristic values with temperature change, which is a general characteristic of electrical resistance, an initial value adjusted at the factory according to the characteristics of each engine may be out of the limit value during use.

Second, since it has the contact resistance structure of the electric resistance track and the brush, there is a lack of accuracy and the reliability of the durability due to the electric noise caused by the surrounding electric devices, harsh operating conditions (dust, moisture, vibration, temperature), etc. It is defective.

Third, because of the mechanical structure of the electrical resistance track and the rotational contact of the brush, in order to change the electrical characteristics, a separate mold and mechanical performance test must be performed, resulting in a time-consuming and costly problem. For example, the limit of rated capacity (0.5 watt rating for commercial vehicles, 1.5 watt rating for heavy equipment), change in resistance value (2.5 kΩ, 5 kΩ, single track, double track).

[Technical problem to be achieved]

In order to solve this problem, the present invention recognizes the magnitude of the magnetism detected by the two sensing bars positioned at mutually different points in one hall element, thereby detecting an unbalance amount of the magnetism generated by the eccentricity of the rotating body. It is an object of the present invention to provide a non-contact rotational displacement sensor that can accurately measure the magnitude of magnetism by rotation.

Another object of the present invention is to measure the amount of change in the current detected by the Hall element according to the size of the magnet as a change in voltage and to use it as an output signal of the sensor. It is an object of the present invention to provide a non-contact rotational displacement sensor capable of quantitatively detecting each position of a rotating body by adopting a method of digitally detecting a current position by changing into a signal.

Another object of the present invention is to replace the contact switch of the mechanical structure, such as limit switch with a non-contact photo coupler, to eliminate the limit life and electrical spark phenomenon that can be caused by mechanical wear, and to reduce the number and size of parts, The purpose is to provide a non-contact rotational displacement sensor that can reduce the manufacturing cost.

Another object of the present invention is to stabilize the output signal by stabilizing unstable amplitude or epicenter level resulting from harsh operating conditions such as temperature change, power supply noise, amplification noise, electric motor, compressor, dust, moisture, and vibration. It is an object of the present invention to provide a non-contact rotational displacement sensor capable of obtaining accurate output values with high linearity and low hysteresis.

Another object of the present invention is to modify the algorithm of the microprocessor without modifying the appearance of the sensor, it is possible to output analog and digital signals with the same product, non-contact rotation that can operate two or more signal switches in various rotation positions The object is to provide a displacement sensor.

1 is a perspective view showing an assembled state of a rotation displacement sensor according to the present invention,

Figure 2 is an exploded perspective view showing a coupling structure of the rotating body shown in FIG.

Figure 3 is a plan perspective view of an exploded state of the rotational displacement sensor according to the present invention.

Figure 4 is a schematic view showing the arrangement of the sensing bar and the permanent magnet of the present invention.

5 is a graph showing the relationship between the voltage and the rotation angle in the rotation displacement sensor according to the present invention,

6 is a flow chart showing the processing of the rotational displacement sensor according to the present invention,

7 is a block diagram of a PCB according to the present invention.

♣ Explanation of symbols for main part of drawing ♣

1: rotary displacement sensor 10: rotary shaft

12: coupling protrusion 20: cover

22: Sensor mounting hole 26: Adhesive injection hole

30: housing 40: rotating body

42a: combining groove 50: permanent magnet

60, 62: sensing bar 70: PCB

72: Hall element 80: O-ring

Detailed Description of the Preferred Embodiments of the Invention

The contactless rotational displacement sensor of the present invention for achieving the above object is a housing having a seating sheet formed on the bottom surface, a cover having a sensor mounting hole and a through hole to cover the housing, and one end is seated on the seating sheet of the housing The intermediate flange is coupled around the through hole of the cover to be rotatably supported in the housing, the upper end of which is connected to the rotating body by a rotating body having a coupling groove formed at one end thereof and a coupling protrusion inserted into the coupling groove. The other end of the rotating shaft connected to the object to be rotated to be measured, the permanent magnet inserted into the base portion of the rotating body, the sensing bar is disposed in parallel surrounding the base of the rotating body to sense the position of the permanent magnet; It is made of a PCB disposed in the housing in the state connected to the sensing bar via a Hall element It shall be.

Hereinafter, a non-contact rotary displacement sensor according to a preferred embodiment of the present invention with reference to the accompanying drawings will be described in detail.

First, Figure 1 is a perspective view showing the assembled state of the rotational displacement sensor according to the invention, Figure 2 is an exploded perspective view showing a coupling structure of the rotating body shown in Figure 1, Figure 3 is a rotational displacement sensor of the present invention The disassembled state is a flat perspective view,

First, as shown in Figure 1, the non-contact rotational displacement sensor 1 according to the present invention is provided with a rotary shaft 10 is formed with a spline for coupling with the object to be measured, such as an engine or a motor frame or a pedal skirt The rotating shaft 10 is rotatably mounted on the housing 30. The cover 20 is covered with an upper portion of the housing 30, and a plurality of wires protrude from the rear of the housing 30. Various types of terminals (not shown) are fitted at the ends of these wires 74 to be connected to connectors or wire harnesses not shown. The cover 20 is formed with a sensor mounting hole 22 penetrating the housing 30 to couple the rotational displacement sensor of the present invention to the object to be measured, and at one end, silicon, etc., to prevent the flow of the wire 74. An adhesive injection hole 26 for injecting an adhesive is formed.

Next, as shown in FIG. 2 and FIG. 3, the rotary shaft 10 is coupled to the rotary body 40 through the lower coupling protrusion 12, and two sensing bars are formed around the rotary body 40. 60, 62 are doubled. Permanent magnet 50 is fitted to the lower base portion 46 of the rotating body 40, the sensing bar (60), 62 is the position displacement of the permanent magnet 50 is transmitted through the rotary shaft 10 Detects and transfers the printed circuit board (hereinafter referred to as PCB) 70. The permanent magnet 50 is inserted in advance during the plastic injection of the rotating body 40, is firmly fixed to the rotating body 40, approximately 90 degrees in the forward and reverse direction by the action of the rotating body 40 and the return spring 82 Rotate reciprocally at an angle of

Here, since the coupling groove 42a into which the coupling protrusion 12 of the line shaft 10 is inserted is formed in the upper head portion 42 of the rotating body 40, the coupling protrusion 12 is formed in the coupling groove ( When inserted into and fixed to 42a), the rotational force of the rotary shaft 10 is accurately transmitted to the rotor 40. In addition, a coupling flange 44 is formed in the middle of the rotating body 40. Therefore, at the time of assembly, the upper head portion 42 of the rotating body 40 is inserted into the through hole 24 of the cover 20, and the coupling flange 44 is mounted around the bottom of the through hole 24 and the sensor. It is possible to rotatably support the rotating body 40 in the housing 30 by being coupled at a proper interval between the balls (32). A tooth part 24a is formed in the upper circumference of the through hole 24. The permanent magnet 50 is inserted into the lower base portion 46 of the rotor 40, and the rotor 40 rotated by the rotary shaft 10 between the base 46 and the coupling flange 44. ), A return spring 82 is wound up to return the back to its original position.

Sensing bars (60) and (62) disposed opposite to each other at predetermined intervals at both ends of the permanent magnet (50) are arranged in parallel to the base portion 46 of the rotating body (40). In addition, extensions 60a and 62a extending in the vertical direction are formed at one end of the sensing bars 60 and 62, respectively, and between the extensions 60a and 62a, a Hall element ( 72 is disposed. The Hall element 72 is coupled to the PCB 70, and serves to transfer the displacement amount of the permanent magnet 50 sensed through the sensing bars 60, 62 to the PCB 70.

Two long grooves 34 into which the sensing bars 60 and 62 are inserted are elongated in the longitudinal direction in the housing 30 constituting the outer shape of the rotational shift sensor 1. A seating sheet 32 in which the seating protrusion 48 formed on the base 46 of the rotating body 40 is rotatably seated is formed therebetween. In addition, a fixing hole 36 for fixing the PCB 70 is formed at the bottom of the housing 30, and at the rear end thereof, the wire 74 is joined together with the upper crimped end portion 28 formed at the lower end of the cover 20. The lower compression end 38 is formed so as not to be compressed and flow.

In assembling, first, the two sensing bars 60 and 62 are disposed in the long groove 34 of the housing 30, and then the extensions 60a and 62a of the sensing bars 60 and 62 are arranged. The PCB 70 is disposed on the bottom surface of the housing 30 in a state where the Hall element 72 is positioned between the holes. At this time, the hall element 72 is fixed to the bottom surface of the housing 30 by welding or the like. Next, the base portion 46 of the rotating body 40 into which the permanent magnet 50 is inserted is placed on the seating sheet 32 of the housing 30. At this time, the return spring 82 is wound in advance between the coupling flange 44 and the base portion 46 of the rotating body 40, one end of the return spring 82 is fixed to the coupling flange 44 and the other end is the housing. It is supported by the inner wall of 30.

Next, the cover 20 is placed on the upper portion of the housing 30 while the rubber O-ring 80 is inserted into the upper head portion 42 of the rotating body 40 so that water or foreign matter does not flow from the outside. Cover and combine. In this process, the wire 74 connected to the rear end of the PCB 70 is sandwiched between the upper crimped end portion 28 of the cover 20 and the lower crimped end portion 38 of the housing 30 and compressed, and then the adhesive injection hole Through (26), the adhesive such as silicone is injected and bonded.

In this assembled state, the coupling protrusion 12 of the rotary shaft 10 is coupled to the coupling groove 42a formed in the upper head portion 42 of the rotating body 40 to complete the assembly, and then the sensor mounting hole 22 Mount the rotation displacement sensor (1) of the present invention to the object to be measured through). At this time, the rotary shaft 10 is coupled to rotate integrally with the rotating part of the object to be measured.

Next, Figure 4 is a schematic view showing the arrangement of the sensing bar and the permanent magnet of the present invention, as shown here, the pair of sensing bars 60, 62, respectively, and both ends of the permanent magnet 50 and When it is located in a straight line, it turns out that it is arrange | positioned so that it may oppose the both ends and predetermined space | interval (air gap). In addition, the Hall element 72 is disposed between the upper and lower extension portions 60a and 62a formed opposite to the ends of the sensing bars 60 and 62, thereby rotating the shaft 10 and the rotating body 40. The intensity of the magnetic field according to the distance change with the both ends of the permanent magnet 50 is transmitted through the) can be transmitted to the Hall element 72.

As such, both ends of the sensing bars 60 and 62 surrounding the permanent magnet 50 are arranged to transmit the magnetic field strength of the same permanent magnet 50 to one hole element 72 at the same time. Therefore, it is possible to compensate the imbalance of the magnetic force line resulting from the disparity (air gap) inconsistency between the rotating body 40 and the sensing bars 60, 62. The electrical signal detected by the hall element 72 is processed into a digital signal by the PCB 70 and then output as an output signal and a switch signal.

Next, Figure 5 is a graph showing the relationship between the voltage and the rotation angle in the rotation displacement sensor according to the present invention. In this graph, the horizontal axis represents the rotation angle ( θ ) of the permanent magnet and the vertical output represents the output voltage (Vref), and the signal output from the sensor 1 is a graph between these rotation angles ( θ ) and the output voltage (Vref). Represented by.

As shown here, it can be seen that in the rotation displacement sensor 1 according to the present invention, the output voltage Vref is obtained in proportion to the rotation angle θ . It is also designed so that at least two shorted switch signals are obtained at two or more specified voltage potentials of the output signal. At this time, the on / off state of the short signal can be appropriately changed as necessary (that is, it is always possible to be always on or always off and kept in the connected and insulated state).

Next, Figure 6 is a flow chart showing a switch signal processing of the rotational displacement sensor according to the present invention. This is performed by the programmable signal processing processor 94 which compares the signal converted into a digital signal in the analog-to-digital converter 98 with the switch value W set in the program and sends out an input / output port output signal. A flowchart showing the process.

As shown, when the watchdog timer and the microprocessor operate in sequence in steps S10 and S12, and a digitized signal is input from the analog-to-digital converter 98 (step S14), firstly, the third switch SW3. It is determined whether the value is smaller than the digital signal value W, and when the value of the third switch SW3 is smaller than the digital signal value W (YES in step S15), the second switch SW2 and the third switch (SW3) is turned on, and the first switch SW1 is turned off (step S16). On the other hand, when the value of the third switch SW3 is larger than the digital signal value W (NO in step S15), the value of the second switch SW2 is compared with the digital signal value W (step S18).

That is, when the value of the second switch SW2 is smaller than the digital signal value W (YES in step S18), the second switch SW2 is turned on and the first switch SW1 and the third switch SW3 are turned off. If the value of the second switch SW2 is greater than the digital signal value W (NO in step S18), the value of the first switch SW1 is compared with the digital signal value W (step S20). S22).

If the value of the first switch SW1 is larger than the digital signal value W (NO in step S22), the first switch SW1 is turned on, the second switch SW2 is turned off, and the third switch SW3 is turned off ( In step 24), when the value of the first switch SW1 is smaller than the digital signal value W (YES in step S22), all the switches SW1 to SW3 are turned off (step S26).

7 is a block diagram of a PCB according to the present invention. As described above, the change of the magnetic field generated from the permanent magnet 50 rotating together with the rotor 40 by the rotary shaft 10 is detected by a pair of sensing bars 60, 62, sensing The combined magnetic field detected by the bars 60 and 62 is an extension part 60a of the pair of sensing bars 60 and 62 in a state of being protruded by a predetermined length in one direction from one side of the PCB 70 and assembled. By being transferred to the PCB 70 by the Hall element 72 disposed between the and 62a, the magnetic field imbalance caused by the eccentricity of the rotating body 40 is compensated for. At this time, the instantaneous magnetic field detected proportionally according to each rotation angle of the permanent magnet 50 is amplified to a high level voltage through the amplifier (AMP) 90, and then through the compensation circuit 91 through the rotation displacement sensor ( It is provided through the wire 74 as an output signal of 1).

The filter 92 positioned at the tip of the input voltage Vcef is composed of an RC circuit, and stabilizes the supply voltage supplied from the electronic control device of the object under test such as an engine or an electric motor to within a range of ± 0.1%. 72) By stably supplying the integrated circuit and the programmer to the signal processing processor 94, it is possible to ensure a stable output signal even when the power supply is unstable.

The signal amplified to a high level voltage is converted to digital by an analog digital converter (ADC) 98 in a programmable signal processing processor 94 in which a nonvolatile memory (EEP ROM) 100 is embedded, and then to the processor 94. The screening process is performed so as to operate within the range of the pre-input voltage.

On the other hand, the oscillator (OSC) 96 separately mounted on the PCB 70 provides a signal in a standard time unit so that the programmable signal processing processor 94 can operate sequentially in time. The watchdog timer (WDT) 102 separately installed on the PCB 70 is installed to prevent a malfunction of the programmable signal processor 94. The programmable signal processor 94 operates a predetermined loop. Afterwards, the programmable signal processing processor 94 is operated by the signal of the watchdog timer 102 to initialize the program.

The programmable signal processing processor 94 generates a signal when the input output signal passes a specific voltage level set to two or more to operate the photo coupler 104 as a non-contact relay switch located in a high voltage region of 10Vdc. The first to third switches SW1, SW2, and SW3 are built in the photo coupler 104.

The PCB 70 is provided as an independent current circuit so that the photo coupler 104 can operate as a short switch of a high voltage supply power source separate from the hall element 72.

[Effects of the Invention]

According to the present invention described above, the non-contact rotation displacement measuring method for recognizing the strength of the magnetic force in accordance with the movement of the rotating body in which the permanent magnet is inserted and the obtained magnetic strength by using an electronic circuit with a programmable signal processing processor It can be converted into digital signal and add switch function that can change the position of the switch without mechanical change, so it can maintain the durability performance of more than 10 million times and maintain accurate measurement error range within ± 1% range. It is possible to provide a semi-permanent sensor that can operate smoothly even in harsh driving conditions.

Claims (5)

A housing 30 having a seating sheet 32 formed on the bottom surface thereof; A cover 20 having a sensor mounting hole 22 and a through hole 24 covering the housing 30; One end is seated on the seating seat 32 of the housing 30 and the middle coupling flange 44 is coupled to the periphery of the through hole 24 of the cover 20 is rotatably supported in the housing 30 Rotor 40 and the coupling groove 42a is formed at the top, One end is connected to the rotating body 40 by a coupling protrusion 12 inserted into the coupling groove 42a and the other end is connected to the rotating shaft 10 to be measured to the rotating object 10, Permanent magnet 50 is inserted into the base portion 46 of the rotating body 40, Sensing bars 60 and 62 surrounding the base 46 of the rotating body 40 and disposed in parallel to sense the position of the permanent magnet 50; Non-contact rotary displacement sensor, characterized in that consisting of a PCB (70) disposed in the housing 30 in the state connected to the sensing bar (60), 62 through the Hall element (72). The method of claim 1, Both ends of the two sensing bars 60 and 62 surrounding the permanent magnet 50 are disposed to transmit the magnetic field strength of the same permanent magnet 50 to one hole element 72. Non-contact rotational displacement sensor, characterized in that the imbalance of the magnetic force lines coming from the distance mismatch between the entire 40 and the sensing bar (60), (62). The method of claim 1, The PCB (70) is a non-contact rotational displacement sensor, characterized in that the programmable signal processing processor of the sensor for changing the operating position of the switch in software without changing the external and internal hardware of the sensor. The method of claim 1, The PCB 70 is a non-contact rotational displacement sensor, characterized in that provided with a filter circuit for stabilizing the hysteresis of the sensor output signal due to disturbance of the external electrical supply. The method of claim 1, Non-contact rotary displacement sensor, characterized in that the PCB 70 is provided with at least one photo coupler (104) switch device.