KR20040101104A - The two-dimensional visible system for the temperature range of break disk - Google Patents

Abstract

PURPOSE: A two-dimensional visualization system of temperature distribution of a brake disk by using a noncontact sensor is provided to extract the accurate data and to analyze judder by measuring temperature of the brake disk with a photo diode, real-time visualizing temperature distribution and removing afterimage with a chopper. CONSTITUTION: A two-dimensional visualization system of temperature distribution of a brake disk(1) is composed of an objective(2) focusing heat radiating from the brake disk, a polarizing filter(3) polarizing the infrared ray region among the concentration area, an iris(4) regulating the light amount of rough infrared rays through the polarizing filter, a photodiode(5) converting into the electric signal in proportion to the radiating light amount, a detecting system(7) in which an analog-to-digital converter is installed to transmit data to a computer(6), and the computer visualizing the distribution of heat of the brake disk two-dimensionally.

Description

The two-dimensional visible system for the temperature range of break disk}

The present invention relates to a two-dimensional visualization system of the brake disk temperature distribution using a non-contact sensor, and more particularly, an objective lens for condensing heat radiated from the brake disk to be measured, a filter for polarizing only the focused infrared portion, and a quantity of light. A detector with an adjustable aperture, a photodiode that converts an electric signal in proportion to the amount of heat radiated light, an A / D converter that transfers data to a computer, and a computer with LabView S / W. The temperature distribution characteristics in the circumferential direction can be visualized in two dimensions with respect to the entire brake disc by time, and two of the brake disc temperature distributions using a non-contact sensor can be used for designing the disc brake and characterizing the judder phenomenon. A dimensional visualization system.

In order to measure the temperature distribution of the disk in the brake dynamometer, a method of directly measuring a thermocouple inserted into or on the disk is mainly used. Since the measurement method can only know the temperature data of a single point on the surface of the disc, the overall temperature curve and information of the disc are unknown and the response time is slow. Therefore, the circumferential temperature distribution of the actual brake disc is shown. It is not possible to determine the cause of the change.

As described above, the method of measuring temperature using a thermocouple inserted into a disk and transmitting using a slip ring or a telemetry system is not easy to install, and in many experiments, replacement by wear is necessary. . In most cases, only a single point of temperature of the disk can be measured, and in the case of a brake dynamometer or a brake disc surface temperature measuring device, the temperature distribution of a representative point is determined by temperature data according to the braking time of each measuring point. Only information is available, and the overall disk temperature distribution cannot be predicted.

The non-contact sensor used for temperature measurement is an optical pyrometer that measures the temperature of an object based on the radiant energy emitted by the object. An important factor in the pyrometer is the wavelength of radiation, which is divided into visible and infrared ranges of 0.4 ~ 20㎛ largely, and pyrometers are classified into two types according to the method of measuring radiant energy.

First, as a sensor used as a total radiation pyrometer, a device such as a metal or semiconductor bolometer or a thermopile is mainly used, and heat radiation energy emitted from an object to be measured is focused. When it is incident on a sensor at a distance, it is a method of measuring the temperature of an object by measuring the temperature emitted from the device as the device is heated by heat radiation energy. In general, the pyrometer using the thermopile element is known to have a minimum response time of 15ms, which makes it difficult to measure the temperature of the object that rotates at a high speed. The advantage is that the signal is stable.

The second is a photoeletric optical pyrometer, which mainly uses semiconductor materials (Si, Ge, InAs, InSb, InGsAs, etc.) as a sensor element to measure the intensity of photons applied to the sensor. It is a method of measuring by converting into a signal. In addition, the photoconductor can be divided into photo voltaic and photoconductor according to the physical quantity changed by the photoelectron. In the case of the photoconductor, photodiode and photomtransister can be divided. Can be.

In the case of the optoelectronic optical pyrometer, the reaction time can be several seconds or less, so the response to the dynamic characteristics of the measurement object is very fast. However, in the case of the photoconductor, when the device is stabilized and receives light, the potential Has a disadvantage that it needs a chopping device to receive continuous signal because it increases and then returns to stabilization state. Photoelectric sensor is sensitive to external noise instead of fast response speed. There are disadvantages.

In order to compensate for the disadvantages of the brake dynamometer or the brake disk surface temperature measuring device, the development of a non-contact pyrometer has been developed, but this is also a measuring method and device for a single point of the disk.

An object of the present invention is to measure the accurate temperature distribution of the entire disk in a high speed state using a non-contact sensor, the objective lens for condensing the heat radiated from the brake disk to be measured, and to polarize only the focused infrared portion A filter, an aperture controlling the amount of light, a photodiode that converts an electric signal in proportion to the amount of heat radiated light, an A / D converter that transmits data to a computer, and LabView S / W are installed. Brake discs using non-contact sensors that can be used for designing disc brakes and characterizing judder phenomena by configuring the system with a computer to visualize the temperature distribution characteristics in the circumferential direction in two dimensions for the entire brake disc by time. The present invention provides a two-dimensional visualization system of temperature distribution.

1 is an overall configuration diagram of the present invention

2 is a state diagram of a computer screen visualized in two dimensions by the present invention;

Figure 3 is a chopper state diagram of the present invention

※ Explanation of codes for main parts of drawing

1: Brake Disc 2: Objective Lens

3: polarization filter 4: aperture

5: photodiode 6: computer

7 detector 8 housing

9: chopper

Hereinafter, the configuration and operation of the present invention will be described in detail with reference to the accompanying drawings.

The objective lens 2 for condensing the heat radiated from the brake disk 1 to be measured, the polarizing filter 3 for polarizing only the infrared portion of the collected portion, and the amount of infrared light passing through the polarizing filter 3 are adjusted. A detection system 7 equipped with an aperture 4, a photodiode 5 for converting an electric signal in proportion to the amount of thermally radiated light, an A / D converter for transferring data to a computer 6, and a labview It consists of a computer 6 with software (LabView S / W) installed.

The optical paths of the objective lens 2, the polarizing filter 3, the diaphragm 4, and the photodiode 5 in the above-described order can be installed in the housing 8 made of aluminum, and the brake is a measurement object. The heat radiation from the disk 1 is collected by the objective lens 2 provided inside the housing 8, only the desired infrared portion is polarized by the polarization filter 3, and the fixed stereoscopic aperture 4 is fixed. Is reached.

The heavy objective lens 2 may use a pair of plano-convox lenses to reduce the longitudinal aberration of the thermal radiation, and the photodiodes 5 may be plural in the circumferential direction of the brake disc. Are arranged in a row, each of which uses a photo conductive indium antimonide (InSb) to have a fast response speed and a wide wavelength band.

In addition, when measuring the temperature at high speed using the photodiode (5), in order to eliminate the afterimage remaining on the photodiode (5) serves as a black body having a size and speed of 1: 1 with the brake disk (1). A chopper 9 is provided between the brake disc 1 and the objective lens 2 on the rotation shaft of the brake disc 1.

The present invention configured as described above is used for non-contact temperature measurement over the entire range of the brake disc 1 to predict brake performance, judging phenomenon, and the like. That is, the brake disc 1 brakes only a certain part corresponding to the area of the brake pad by friction contact. At this time, when the braking force is generated by the friction force between the pad and the brake disc 1, heat is generated and radiated to the atmosphere. . Since the brake disc 1 before heat dissipation does not have a uniform temperature distribution, thermal deformation occurs and the thickness of the brake disc 1 is changed to cause a judder phenomenon, which causes quality problems such as deterioration of braking force and vibration. .

For this reason, there is a need for research for improving the quality problem by measuring the temperature distribution of the brake disc 1, and a suitable measuring device is provided by the present invention.

In the brake braking experiment, the surface of the brake disc 1 is chemically reacted by friction with the pad, so that oxidation occurs in part. Therefore, since the emissivity on the surface of the brake disc 1, which was initially predicted, is changed, it is required to develop a signal processing technique that can measure the surface temperature even in an environment where the emissivity may change slightly. In order to cope with the change in emissivity, the temperature value of the reference point is measured by using a thermocouple, and the emissivity value of each point can be obtained to continuously correct it.

In the real-time brake braking experiment, when measuring using a continuous non-contact infrared sensor photodiode (5), the chopper to play the role of a black body because the control and signal processing techniques for the residual image remaining on the photodiode (5) is required ( 9) is installed on the rotating shaft of the brake disc 1 to perform rapid data measurement and to remove the residual image remaining on the photodiode 5. That is, the chopper 9 installed in the shaft of the brake disc 1 has a hole having a diameter of a pyrometer in the radial direction, through which the pyrometer measures the temperature of the brake disc 1, and like the shaft, A system is provided in which the afterimage is removed by the rotating chopper 9.

In addition, a photoelectric sensor is used as a semiconductor device as a configuration of a radiation thermometer, which changes electrical conductivity in proportion to incident thermal radiation. Unlike a total radiation sensor such as a thermopile, it does not detect the entire wavelength band but detects a certain wavelength band according to the characteristics of the semiconductor device. Therefore, the speed response (nm) is generally fast. . In the present invention, a plurality of photodiodes 5 as described above are provided in a line to form a line sensor so that the temperature distribution of the entire brake disc 1 can be visualized.

Therefore, a system that enables fast data acquisition and heat island visualization using fast response (40 kHz or less) pyrometer selection and FIFO memory of Labview hardware is constructed.

That is, in the present invention, a PC (photo conductive) type indium antimonide (InSb) having a relatively fast response speed (5 sec) and a wide wavelength band (1 to 6 m) is adopted as a detection element, The thermal radiation is converted into an electrical signal through the optical system and the detection system 7 of the A / D converter and transmitted to the computer 6 in real time. The computer 6 is equipped with LabView S / W to visualize the acquired data in two dimensions (2-D).

Heat radiated from the brake disc 1 to be measured is collected through the objective lens 2, reaches the diaphragm 4 through the polarization filter 3 for polarizing only the infrared portion, and transmits the data through the photodiode 5. Will be collected. The collected data is transmitted through a detection system 7 equipped with an A / D converter for transmission to a computer 6 including software that can be visualized in real time.

In this way, the thermal radiation from the brake disc 1 to be measured is converted into an electrical signal through the optical system and the detection system 7, and the heat island and temperature distribution of the brake disc 1 are distributed by a computer 6 equipped with visualization software using LabView. It can be known in real time and can be used to identify the judder phenomenon that is most problematic in the braking system.

As described above, the present invention provides a system for measuring the temperature of the brake disc 1 by using the photodiode 5, which is a non-contact sensor, and enables the measurement of the temperature distribution over the brake disc 1 in real time. It can be visualized in two dimensions, and by using the chopper (9) to remove the residual image remaining on the photodiode (5) it is possible to extract only the accurate data, it is possible to experimentally approach the judder vibration that was previously impossible to interpret .

Claims (4)

An objective lens 2 for condensing heat radiated from the brake disc 1, a polarizing filter 3 for polarizing only the infrared portion of the focused portion, and an aperture for adjusting the amount of infrared light passing through the polarizing filter 3 ( 4), a photodiode 5 for converting an electric signal in proportion to the amount of thermally radiated light, a detection system 7 equipped with an A / D converter for transferring data to a computer 6, and a lab software. A two-dimensional visualization system of a brake disc temperature distribution using a non-contact sensor, characterized by comprising a computer (6) installed to visualize the heat distribution of the brake disc (1) in two dimensions. The chopper (9) according to claim 1, wherein the chopper (9) having a size and a speed of 1: 1 with the brake disc (1) in order to eliminate an afterimage remaining on the photodiode (5) between the brake disc (1) and the objective lens (2). ) Is a two-dimensional visualization system of the brake disk temperature distribution using a non-contact sensor installed on the rotation axis of the brake disk (1). The system of claim 1, wherein the photodiode (5) is a PC (photo conductive) type indium antimonide (InSb). The brake disc temperature distribution using a non-contact sensor according to claim 1, wherein the objective lens (2), the polarization filter (3), the aperture (4), and the photodiode (5) are integrally installed in a housing (8) made of aluminum or the like. 2D visualization system.