TWI258571B - Automatic testing system for vibration and noise of electric hand drill - Google Patents

Abstract

The present invention mainly provides an automatic testing system for vibration and noise of electric hand drill, including a holding unit, a noise isolation chamber, a signal testing unit and a data processing unit, in which the holding unit has a robotic arm holding an electric drill on a conveyor and placing it in the noise isolation chamber and further placing it back on the conveyor after finishing test thereof, a sound-absorbing material is stuck on the inner surface of the noise isolation chamber to form an open and gigantic spatial sound field; the signal testing unit is disposed inside the noise isolation chamber so as to perform rotation speed and noise tests simultaneously and transmit the testing signal through a digital interface circuit to the data processing unit, and the data processing unit is built in the standard deviation of rotation speeds of the electric drill and the noise power values so as to carry out real-time analysis and processing on the obtained rotation speeds of the electric drill and the noise data and inspect if the electric drill will pass a quality inspection standard.

Description

1258571 IX. Description of the invention: [Technical field of invention] The present invention relates to an automatic detection system for vibration and noise of a portable electric drill, in particular to the advantages and functions of rapidly detecting and analyzing the rotational speed and noise of a portable electric drill, and at the same time achieving An automated inspection system that requires modern automated quality control. [Prior Art] According to the general decision, there are two factors in the quality of the drill. The first item is the efficiency of power transmission. The second is the vibration and noise problem. Among them, the power transmission efficiency and the transmission of the gear are poor, and the rotation error The main reason is that the manufacturing error of the €_part gear itself has no wheel_wei condition; and the noise lion is judged by the gear group. In addition, the enemy's hearing is screamed by people, and the connection between the material and the electric drill's quality can only be based on _ human experience plus shutting down, subjective (four) and lacking; the test and theory are fresh, it can be seen that the Dalong (10) product The degree of management, this method does not match the use. At the same time, as for the goal of money automation (4), manual testing is bound to replace the new automatic detection technology. The noise caused by the friction or collision of the teeth is amplified by the speaker effect of the hand tool housing, thus forming an irritating noise of the electric drill. At present, in order to cope with the operation of the production line, the technicians often use the hearing to detect the running noise of the electric drill on the line, and # judge the electric drill as a good or defective product based on the sound quality and volume of the noise. Although this method is conducive to on-line testing, human hearing tolerance (4) fatigue or ring needles are generated. With the development of the electronics industry, the vibration noise detection instruments are constantly changing. 1258571 The academic community often uses the noise detection method to analyze and diagnose mechanical systems. This method is characterized by using a microphone to extract the noise signal of the mechanical system, and at the same time, with the spectrum analyzer to analyze the data. The detection method mainly involves the data and possible Comparing the transmission components that produce the corresponding frequencies, the vibration noise source of the system can be determined (see References 1-7). This type of method uses sophisticated instruments and equipment, so when special consideration is given to environmental noise, it is common to use a semi-unsounding line without a soundproof room as a test location, but often because of the high equipment costs, which affects the industry. Willingness to invest. In addition, the speed of the drill is affected by the load in addition to being driven by the motor. If the motor input speed is unstable or the load changes during the test, the frequency of noise generation must be changed. At the same time, the noise shaft, bearing and record group transmission of the gear set will inevitably be interfered by factors such as damping or resonance, and the signal analysis method will be deepened. Therefore, the current noise detection method has not replaced the human ear and established an effective line. Detection Technology. In view of the importance of the quality inspection of electric drills to the industry, the inventors have developed an automated on-line inspection technology for portable electric drills according to the following objectives. 1. Establish the correct quality test standards for electric drills. 2. Establish a fast and efficient automatic measurement and analysis system. SUMMARY OF THE INVENTION The purpose of the present invention is to provide a portable electric drill vibration noise automatic detection system 'mainly has the advantages and functions of quickly and automatically detecting and analyzing the rotational speed and ° dullness of the portable electric drill, and achieving modernization automatically Requirements for quality control. In order to achieve the above objectives, the Japanese-made system design - a portable vibration vibration 1258551 automatic detection system, the money contains - secret unit, the transmission: the electric drill on the belt is placed in the noise isolation box for detection, signal detection unit and Data processing unit: Among them, the instrument σ hai signal test list is in the test after the "re-reviewing material: s; r test" and the surface is attached to the fine material (four) mail butterfly: the detached box body set (four) sound _ Box _ ah into the digital interface "_ _ _ ^ do the unit; to;; at: ^ to establish a power of the 胄 胄 胄 姆 嫩 嫩, _ _ _ _ _ _ data for real-time analysis and processing, and detection Whether the drill passes the quality inspection standard. [Embodiment] With regard to the technical means by which the present invention is achieved by the above-described objects, a preferred embodiment will be described in detail below with reference to the drawings. • This month is mainly for the development of “speed detection” and “noise detection” technologies. Therefore, the inventors have detailed descriptions of the “rotation detection” and “noise detection” detection techniques: 1. Speed detection: Unstable rotating mechanical systems, the traditional signal manipulation technology is very easy to produce spectral drift. In order to improve this-deletion, the inventors developed an angle-based technique, and measured the width of the Weibo wave as the basic property of the measurement and measured the length of time. Due to the technology used in the invention 1258571 ^ based on the test, shame can correctly grasp (four) the rotation rate _ ‘ and can calculate the rotation speed of the rotation (four) system: the dynamic is quite helpful. The invention mainly adopts the quality inspection standard for establishing the output speed of the electric drill by using ―^ 八亚, and the invention adopts the square money line of the number of digits: _take and subtraction transmission, therefore, the speed detection of the tree is not only not disturbing the interference 'And can detect off the high-speed machine. The sense of the invention · optical incremental coding "main, usually the city optical encoder is mostly processed by the signal, can be limited to each rotation cycle TTL pulse wave, the invention is to measure the time occupied by the pulse wave, and calculate the _ speed of the rotating shaft. The pulse width of the encoder is inversely proportional to the resolution of the encoder. The fineness is limited by the manufacturing (4), and the *exposure material has an equal interval, so it must be well corrected before use to correct the error. At the clock speed, the daily pain of a pulse wave is short. In order to detect the high rotation speed, the present invention uses 20 MHz; s-slot $ is used as the timing clock. Therefore, the calculation of the rotational speed can be expressed by the following formula . Open " number 20x1 〇6ω= -Ί转/sec] 1.2χ1〇ς ΡχΝ L—“-'[转/分] where 'ω is the speed, ρ is the resolution of the encoder, and Ν is the time inside the pulse Pulse [1] When the amplitude of the coded H and the (four) (four) pulse are both set to a fixed value, the present invention has a certain amount of error, and the error tilting speed increases and increases, please refer to the first figure. The encoder error detection (4) (9) chats between the speeds of 12558571 'time error will be linear. Since the current speed of the portable electric drill is mostly below 500rPm, it can be seen from the first figure that the rotational speed error can be controlled within 〇. The internal speed detection method within 045% has the advantage of being able to call and accurately detect the dynamics of the rotating shaft. [1] It can be seen that the average speed of the rotational speed of the recording shaft in each pulse width can be measured; since the pulse wave elapses for a short time, the measured value can show the turning speed of the rotating shaft at that point. . In the development process of the present invention, the inventor inputs a fixed voltage (2 to 7 DCV) to the drive motor of the electric drill, and installs an encoder at the output end of the electric drill, and the rotational speed of the quantity_ is transmitted to the electric service through the interface device, through a rotation After the job, data analysis can be carried out; there are two kinds of analysis methods we use. The first method is to adjust the average standard spot difference of each speed in each mechanical cycle to match the input. The difference between the voltage and the voltage. Since the motor of different electric drill configurations has different characteristics, the inventor further converts the relationship between the standard deviation of the rotational speed and the voltage into the _ of the fresh-keeping speed by the value of the Spline Fitting method, and divides the rotational speed difference with the view. The inventors have found that the second method of measuring the electric drill is to convert the speed of each of the mechanical cycles into a spectrum analysis, and the parts used by the electric drill will cause a large amount of money to be recorded. The shame analysis helps to understand the condition of the internal components of the drill. Second, the noise detection: In the present invention, the ° sound detection is carried out in conjunction with the rotation speed detection, that is, the use of the stone... (four) the speed of the encoder, the pulse wave of the encoder will simultaneously trigger the noise measurement to take the noise of the electric drill 1258551 9 Generally referred to as Order Tracking technology, the sampling data is not separated by isochronous separation, so the present invention can still sample the noise signal at a specific angle when the rotation speed changes, and eliminate the loss of the specific frequency due to the change of the rotation speed. Data sampling. Since the electric age sound directly affects the maker, the financial formula must take into account the human ear's perception of the % sound. In the early stage of research and development, the inventors measured the sound power of the gear set noise radiation (SPE) by internationally accepted measurement methods and standards (Bile 579), and then calculated the sound power generated by different electric drills under different voltages. By making a relationship between the sound power and the input, the inventor can further analyze the relationship between the sound power and the standard deviation of the rotational speed. The structure of the electric drill includes a motor, a gear set, a casing, a power cord or a battery, etc. In order to simplify the development of the invention, the inventor removes the electric slanting shell, only protects the motor and the gear set, and focuses the noise detection on the gear. On the group. Since the transmission error of the gear set has a considerable correlation with the gear noise, the cause of the transmission error of the gear is that the gear is improperly fitted or poorly assembled. However, it is extremely difficult to limit the construction of the electric drill to the structure of the electric drill. The solution to the problem is that it is extremely difficult. The solution in July is to control the magnitude of the input voltage and keep a small amount of load = load to keep the motor speed. So, _, the speed detection is equal to the transmission error k measurement 'Next, combined with the speed detection and noise detection, synchronous data manipulation method to handle the speed and the sound signal, so that the dynamic gear error of the electric miscellaneous wheel set can be established The relationship between noise. ~ Third, the establishment of quality testing standards using multiple electric drills for speed detection and noise detection results, the inventors established a 1265851 set of electric drill quality inspection marked in the mine h, u tree, the moon and the moon have a money in Different months, J, speed standard deviation and noise sound power, and according to the average and tolerance I, pull _ + 疋 fiber, mouth mouth take the 磬 京 Jing Jing ^ Finance and then any __ speed standard deviation and The sound power is familiar with the sound, and the bad products are collected. So the following two formulas can be obtained: The p is regarded as the rotation speed detection standard: I mouth speed standard Luping ^ A [2]

Noise detection standard: House noise (SPL) ^^aMW(SPL) ^ A2 [3] Power = Xu = tolerance of the standard deviation of the drilling speed, noise of the drill

In order to test the feasibility of the above technology, the inventor specifically called for the work of measuring the speed and noise in a closed room, and the room (10) Wei noise control

Below 30dB, the sound absorption material f is attached to each wall, roof and floor. The average sound absorption rate of the sound absorbing material is greater than 0.5. The amount of hardware _ is the second riding indication, and the electric drill to be tested (including motor and gear) The group is mounted on a special measuring platform. As shown in the third figure, the platform is about 80cm away from the ground. Other related measuring equipments include: 1. Incremental encoder (resolution is 1024 pulses/circle). 2. Bikai 2238 嗓 sound meter. 1258571 3. Advantech PCL816 AD interface card. 4. Timing interface card (the interface card is equipped with a 20MHz quartz oscillator, two sets of counting devices, and two sets of operational amplifiers). 5. Personal computer. 6. Programmable DC power supply. The test procedure can be expressed as follows: 1. Place the tested drill on the safety test platform; connect the output shaft of the drill to the rotary encoder and place the noise meter 25 cm away from the contour of the drill. 2. Start the DC programmable electric secret device, input the mosquito voltage to the _ motor; connect the output terminal of the encoder to the timing interface card, and connect the noise meter output to the interface card. 3. The encoder provides a - pulse counting device on the timing interface card to enable it to count the clock of the quartz vibration (four). When the encoder provides the next wave signal, the counting device stops immediately. And transfer the number of clocks to the operational amplifier to calculate the instantaneous speed. At this point the second set of counting devices will be activated and begin counting the number of clocks in the quartz oscillator. The pulse signal of the 4 encoder will simultaneously touch the crane interface card to capture the information signal. 5.1 Ten-time job and noise (4) are stored in the electric core, waiting for the power to be completed - a mechanical cycle, that is, stored on a computer hard disk; 6. Data analysis (speed standard deviation, noise sound power). Next, the speed data analysis was carried out. The inventors tested 20 electric drills respectively, using the equipment and procedures described above. As shown in the fourth figure, the speed curve of an electric drill at different input voltages of 1258571, the abscissa is the rotation angle of the output shaft of the electric drill, and a total of four turns are recorded; the ordinate is the output speed (rpm) of the electric drill, and the fourth The input voltage value corresponding to each curve is indicated on the right side of the figure. It can be seen from the fourth figure that the rotation speed of the electric drill increases with the increase of the input voltage, and the degree of the speed curve is relatively increased. In order to facilitate the analysis of the size of the oscillation, the inventors defined the standard deviation between the average speed and the speed of the electric drill, and the calculation formulas are as follows: Average speed = i instantaneous speed 値, μ___ [4] Standard speed difference = Σ (instantaneous speed 値 / - Average speed corpse — \ [5] where '# is the number of _ speed values for all quantities _. The standard is the same as the average speed and speed of the different voltages. (4) The speed of the electric drill is marked with the standard The increase in the number of rpm increases, two (four) her 彡 柳 Liu 连 连 = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = 336.2796 424.4354 495.9106 Poor 2.3808 4.1232 5.5900 7.2368 9.2551 10.5968 The analysis of the branch, the speed of each electric drill at different input voltages of 12 1258571 'quasi-difference. Different electric drills show different shock conditions; although the standard deviation of the speed will increase with the average speed And increase, but the standard deviation of the speed of each support and the level of feeding speed but the financial side, such as the sixth _ and 卩 is a unified series with electric drills in different input voltage rotation county The distribution of the towel, the dotted line represents the average standard deviation, and the '0, and '*, the maximum and minimum standard deviation of the sub-sales table, that is, the speed of all the drills of the fortune' is the same as the sixth figure. In the area between '., and '*, it is similar to the fifth picture. The input f pressure and the rotational speed difference have a linear relationship. Since the individual drills are equipped with _Dc motors, the same input voltage is made. Different inversions will be generated on different electric drills. The inventors have used the numerical analysis (Spline Fitting) side/i: the obtained re-analysis of the dragon, and corrected the abscissa of the sixth figure to the average speed of the material. The result of the correction of the seven rides, the seventh standard can be used to touch the standard deviation of the speed of the electric drill at the single speed. Continue to observe the crane on the side of the electric drill, _ divide the average speed and the speed difference , you can get the relationship diagram of the eighth figure. As shown in the eighth figure, the actual and the number of the X number represent the average standard deviation and the percentage of the rotation speed, and the 〇, 、,, 、, 、, The smallest percentage value. The first person shows an interesting phenomenon That is to say, the standard deviation and the percentage of the speed will decrease as the voltage rises (the speed increases), and the percentage of the scale decreases and the age test results are affected by the surface (_speed). In other words, the speed detection The voltage of '5 to 7 volts' and only need to calculate the standard deviation of the speed of the electric drill to determine the _ is a good product. Using the above analysis method, the inventor revised the formula [2] as follows: 13 [ 6]1258571 Speed detection standard: Standard deviation of speed -^l^-xlOO% < A% where d is an arbitrary constant, which can be determined by the drill manufacturer according to actual needs. In the present invention, the J value is approximately equal to 2.8, as shown in the eighth figure.

The noise data analysis is continued, and the noise detection method is the same as the speed detection method. At different input voltages, the sound power of different electric drills is arranged as shown in the ninth figure. As can be seen from the ninth figure, the electric drill noise exhibits a similar increase in the negative exponential curve as the input voltage increases. Where χ represents the average sound power, and +, and, 〇 represent the maximum and minimum sound power values, respectively, and the three dashed lines shown in the ninth figure are based on the Spiine Fitting. The result is helpful to understand the relationship between the sound power and the input voltage. Since the sound power values of all the tested drills fall within these two curves, it is possible to set the pass rate of 9〇% according to the speed detection and determine The noise standard of electric drills. Because the drill has different noise at different input voltages

The electric shock noise detection standard designed by the inventor of this inventor must take into account the magnitude of the input voltage, and the correction formula [3] is as follows: Noise detection standard:

(i) Input: DC 5V, drill noise $ 68 6dB

[7]

(9) Input: DC 6V, electric drill noise 幺 71.3dB (iii) Input: DC 71⁄4 electric drill noise $ 73. lcjB Based on the above established testing techniques and standards, the inventor made a fully automatic detection system. The controller of the system uses a personal computer and cooperates with the graphic control monitoring program to input and discharge the drill. The structure of the system is as shown in the tenth figure. The detection unit and the data processing unit of the 14 1258571 λ respectively include four parts of the clamping unit 1, the noise isolation box 2, and the like. I will introduce the functions of each department as follows...卩stable)'The main system is to take the clamping unit and use the AC brake motor to guide the screw:: The electric head can pick up the electric drill stably; when the central one is ^^仃夹赞田鳞早Μ The conveyor belt on the left side will send the electric drill to the base to hold the electric drill and send it to the detection position. After the test is completed, the electric drill will be put back to the conveyor belt for the next step of work. The Japanese phase 2 'main system to overcome the environmental sound yin _ _ to facilitate the online detection of the electric drill voice, the material of the box is made of wood, and the sound insulation material is placed on the inside of the box, the sound insulation material - a total of three layers, on, The lower layer is a m-knife-layer light board with a thick knife. Therefore, the sound insulation box 2 can effectively reduce the environmental noise factor, and the effective detection volume of the noise soundproof box 2 is about 9〇x 50x 50cm3, and The volume of the drill under test is about 45〇cm3, and the volume ratio of the two is 500. :1. In addition to the soundproofing material, the sound-absorbing cotton of the sound-absorbing rate of about ο.? is used to absorb sounds, so that the sound-sounding _ 2 (10) can simulate - an open huge space sound field; the nickname k measuring unit, the signal detecting unit It is placed in the noise isolation box 2, (4) to order the "rotational speed test" and the "noise test"; in terms of the speed test, the present invention uses the rotary coded Wei-precision time-series device to check the rotational speed of the shaft 'sub-transmission digits The interface circuit transfers Wei's Xunlin to the power. In order to facilitate the action of the mechanism, the unit is placed in a swaying manner and the encoder is mounted on the bottom layer of the soundproof box. In terms of noise testing, the present invention uses a The piezoelectric microphone measures the noise signal during the running of the electric drill, and transmits the noise signal to the electric _ through the A/D interface circuit. The unit can _code the modulating pulse side microphone and the A/D interface to make the signal 撷The frequency taken corresponds to the rotational frequency of the drill. Data processing single it 'mainly _ signal detection unit to obtain data for electric drill quality analysis' This unit is a program set in the _s operating environment, the main analysis of the project is based on the above formula [6] and [7] , the drill signal that will be captured

= Immediate analysis and processing; through the analysis of this unit, it is possible to effectively detect whether the electric drill passes the quality detection and the results can be directly displayed on the computer screen, which is beneficial for the user to observe. It can be seen from the above description that the construction method provided by the present invention has the following features: The main purpose is to perform the quality inspection of the electric drill in a fully automated manner, and the invention can be continuously provided due to the problems of mechanical preparation, fatigue and 7 machines. The inspection work can be used for mass production, saving manpower, and reducing production costs. 2. The invention can clearly measure the output speed and noise signal of the electric drill, and calculate the standard deviation of the electric drill and the rotational speed and the sound of the electric drill. Power, and the test results are compared with the product standard, and judge whether the drill is a good product; because the quality control 1 is all processed by the computer's, therefore, its objectivity is far stronger than the human reading, and at the same time, the detection process is unexpected. Interference can improve the lack of manual detection. 16 1258571 Inventing the positioning of the personal computer-controlled miscellaneous system, the detection and signal, and other actions can not only effectively integrate the system (4), but also achieve optimal control. Efficacy. 4· This section X Ming each unit adopts modular design, which is convenient for maintenance and inspection of the status of each unit and simplifies maintenance. Preface, and the main control program can follow the above-mentioned technical means disclosed in the "Construction Method of Automatic Vibration and Noise Detection System for Portable Drills", which can effectively solve various problems of traditional manual detection and conventional spring detection instruments. And to achieve the intended purpose and effect, it is the use of the technical ideas of the natural law to claim the invention in the patent law is correct, 提出 apply in accordance with the law, 恳 钧 钧 详 详 详 详 详 详 详 详 详 详 详Xin. [References] 1. P.D. McFadden, 1985, NDT international, ς4Α signal processing technique for detecting local defects in a gear from the signal average of the vibration".

2. PD McFadden, 1986, Journal of Vibration, Acoustics, Stress, and Reliablity in Design, 108, 165-170, "Detecting fatigue cracks in gears by amplitude and phase demodulation of meshing vibration". 3. Rust, FK Brandi, 1990, 13th Fisita Congress, ''Definition, identification and elimination of obtrusive gear rattle noise”. 4. FK Brandi, H. Schiffbaenker, and GE Thien, 1989, Intemoise Conference, UA concept for definition of subjective noise character - as a basis 5. H. Schiffbaenker, A. Rust, and FK Brandi, 1989, Autotech, uThe suppression of unwanted noise phenomena in vehicles - a task to be achieved mainly by optimising subjective noise character. 6 · H. Optiz, 1969, Philosophical Transactions of the Royal Society, “Noise of gears”. 7. K. Genuit, 1987, SAE 870959, “Investigation and simulation of vehicle noise using the binatural measurement technique”. 17 1258571 Brief description FIG lines when a resolution of the encoder lOOOppr, error analysis of the timing device of FIG different rotational speed. The second figure is a hardware architecture diagram of the measurement system of the present invention. The third figure is a schematic diagram of the electric drill test platform of the present invention. The fourth picture is a graph of the speed of the electric drill at different voltages. The fifth figure is the relationship between the speed of the electric drill and the standard deviation of the speed. The sixth picture is the relationship between the input voltage and the standard deviation of the speed. The seventh figure is the relationship between the speed of the electric drill and the standard deviation of the speed. The eighth figure is a plot of the standard deviation percentage versus input voltage. The ninth figure is a diagram showing the relationship between the noise power of the electric drill and the input voltage. The tenth figure is a schematic diagram of the automatic drilling system of the present invention. [Main component symbol description] 1 --- clamping unit 11---conveyor belt 12---electric drill 2-one noise isolation box 18

Claims (1)

!258571 Ten patent application scope: 1 portable electric fault vibration noise automatic inspection system, the test money includes - clip: early 7L: - noise isolation box, - signal detection unit and data processing unit; it has a mechanical arm The electric drill on the conveyor belt can be placed in the noise compartment π detection' and in the inspection, the gift will be returned to the electric spectator σ: the occlusion surface of the box is affixed with sound absorbing materials to form _open: Carry out the speed and: - the poor material processing unit establishes the standard deviation of the speed of the electric drill = to j treatment material, which can take the electric drill speed and noise data of the electric rope into the t-wool sound power value Testing standards. Analysis and processing when 卩p, and detection 19