CN107167106A - Sebific duct based on minimum two-multiply law withholds performance rating method and detection means - Google Patents

Abstract

The present invention proposes a kind of sebific duct based on minimum two-multiply law and withholds performance rating method and detection means, and the data measured using minimum two-multiply law Linear displacement transducer are post-processed, and then evaluates the deviation from circular from of sebific duct buckling piece.Mainly include the following steps that：Step 1, it is arranged circumferentially eight sensors in space, calculates coordinate during each sensor measurement station；Step 2, the Least Square Circle central coordinate of circle for calculating sebific duct buckling piece cross section profile；Step 3, Calculation of Roundness Error.

Description

Hose crimping quality assessment method and detection device based on least squares circle method

technical field

The invention proposes a rubber hose crimping quality evaluation method and detection device based on the least square circle method. The method is used for measuring the roundness of the section of the rubber hose crimping part, and can effectively complete the measurement process of the rubber hose crimping part after extrusion molding.

Background technique

The rubber hose assembly is formed by buckling the hose body and the connecting joint, and is used to transport fluid with a certain pressure and flow rate, and connect the separated oil circuit units. Because of its special flexible function, it is easy to install and connect, can absorb shock and reduce pipeline vibration. It is an important pipeline component in fluid transmission and control systems. It is widely used in processing equipment, construction machinery, transportation machinery and mining machinery, etc. field.

Oil leakage at the buckle of the hose joint is the main failure mode of the hose assembly. During the use, there have even been serious safety accidents caused by the buckle of the hose assembly being pulled out or broken, causing casualties. It can be seen that it is very important to improve the crimping performance of the rubber hose assembly and improve the crimping reliability. The crimping size is a key parameter in the molding process of the rubber hose assembly, which is directly related to the performance and reliability of the rubber hose assembly. The crimping quality inspection of the hose joint is an important step in the production of the rubber hose.

In engineering practice, the airtightness of the hose buckle is closely related to the size and roundness of the buckle section. At present, production units still mainly use vernier calipers for manual measurement. The work is highly repetitive, the labor intensity of inspectors is high, and the detection methods are relatively backward. Full inspection cannot be realized and it is easily affected by people’s subjective influence. There is no way to accumulate and save detection data. It is conducive to technological improvement and production improvement; the sampling method cannot meet the increasing product quality requirements. The actual measurement measures the dimensions of several opposite sides, as long as the dimensions of each opposite side are within the tolerance range, and the difference between the maximum value and the minimum value does not exceed the allowable value, the crimping process is considered qualified. In fact, calculating the roundness error by the diameter of the opposite side cannot effectively guarantee the roundness of the section. The truly effective method should be calculated by the radius error.

Contents of the invention

In order to solve the above problems, the present invention proposes a rubber hose crimping quality evaluation method and detection device based on the least squares circle method. The least squares circle method is used to post-process the data measured by the linear displacement sensor, and then evaluate the quality of the rubber hose crimping parts. roundness error.

The purpose of the present invention is achieved like this:

A method for evaluating the crimping quality of rubber hose based on the least squares circle method, comprising the following steps:

Step 1. Calculate the coordinates of each sensor when measuring the station: the sensor probe coordinate system ΣOXY, eight sensors are evenly arranged in the circumferential direction of the space, and the distance between the sensor probe and the origin O of the coordinate system Σ at the initial position is A mm; when the probe When it is at the measuring station, suppose the displacements of the measuring rods of each sensor after conversion are S ₀ , S ₁ , S ₂ , S ₃ , S ₄ , S ₅ , S ₆ , S ₇ , then the coordinates of each point in the polar coordinate system Respectively (S ₀ +A,0),

Step 2. Calculate the least squares circle center coordinates of the section profile of the hose crimping part: Substitute the coordinates of the eight measuring points into the following formula to obtain the least squares circle center coordinates G(a,b) of the section profile to be measured

In the formula, i is the serial number of the measuring point, which are 0, 1, 2, 3, 4, 5, 6, and 7 respectively;

r _i (i.e. S _i +A) is the distance from each measuring point to the origin O;

_θi is the angle formed by the line connecting each measuring point with the origin O and the positive semi-axis of the X axis.

Step 3. Calculate the roundness error: first calculate the distance between each measuring point and the center of the least square circle, which are R ₀ , R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , R ₇ , and find out The maximum and minimum values are R _max and R _min respectively, and then the least square circle center coordinate G(a,b) is used as the center, and two concentric circles with R _max and R _min as the radius surround the contour to be measured , so the roundness error is:

f _LS =R _max -R _min

A rubber hose crimping quality evaluation device based on the least square circle method, mainly including a chassis, a push-pull electromagnet, and a linear displacement sensor. Eight linear displacement sensors and push-pull electromagnets are evenly arranged circumferentially within the spatial range, and the push-pull electromagnetic Both the iron and the main body of the linear displacement sensor are fixed on the back cover of the chassis, and the push-pull rod of the push-pull electromagnet is fixedly connected with the measuring rod of the linear displacement sensor; Therefore, the voltage signal data of the linear displacement sensor is collected to the host computer for subsequent processing. The output signal of the sensor is 0-100% of the input DC voltage value, and the voltage change corresponds to the displacement change.

Before the measurement, the sensor probe is at the initial position, and the distance between the probes is the smallest at this time; then the push-pull electromagnet is energized to drive the linear displacement sensor rod to move backward, and the workpiece is placed in a suitable position; then the electromagnet is powered off, At this time, the sensor probe touches the section to be measured, and the measurement data, that is, the voltage signal, is transmitted to the host computer through the serial communication acquisition card to calculate the section size and roundness error and give a pass or fail mark.

The advantage of the present invention is that: compared with the lack of principle of manual detection and a large amount of repetitive work, the displacement data is collected by a displacement sensor with a high degree of automation to calculate the roundness of the section profile of the rubber hose crimping part on the upper computer, which can effectively solve the problem of manual detection efficiency. low and low detection accuracy. This method is suitable for the measurement of the roundness of similar workpieces, the calculation is fast and accurate, and the automation level of the detection is improved.

Description of drawings

Fig. 1 push-pull type electromagnet, linear displacement sensor position arrangement diagram in the present invention;

Fig. 2 is a schematic diagram of the roundness error evaluation by the least squares circle method in the present invention.

detailed description

The specific embodiment of the present invention is described in detail below in conjunction with accompanying drawing:

As shown in Figure 1, the sensor and the electromagnet are fixed on the back cover of the equipment case, and the eight sensors are evenly arranged in the circumferential direction, and the angles formed by the axes of adjacent sensors are all 45 degrees. When the electromagnet is energized, the probe of the linear displacement sensor is kept away from the origin of the coordinate system Σ, and the crimping part to be tested is placed at this time; after the electromagnet is powered off, the sensor probe presses the profile of the crimping part under the action of the return spring, so that the host computer Collect data to calculate contour roundness error.

Step 1. Calculate the coordinates of each sensor when measuring the station (see Figure 2): the sensor probe coordinate system OXY, the coordinates of each sensor probe in the polar coordinate system at the initial position are (A, 0), (A, π),

When the sensor probe is close to the contour and is in the measuring position, each measuring point is P ₀ , P ₁ , P ₂ , P ₃ , P ₄ , P ₅ , P ₆ , P ₇ , since the movement displacement of each probe is S ₀ , S ₁ , S ₂ , S ₃ , S ₄ , S ₅ , S ₆ , S ₇ . At this time, the polar coordinates of each measuring point are (S ₀ +A,0), (S ₄ +A,π),

Step 2. Calculate the coordinates of the least square circle center of the section profile of the hose crimping part (see Figure 2): at this time, r ₀ , r ₁ , r ₂ , r ₃ , r ₄ , r ₅ , r ₆ , and r ₇ are respectively S ₀ +A, S1+ _A , S2 _{+ A} , S3 ₊ A, S4+A, _S5 +A, _S6 + _A , S7+A. Substituting the coordinates of the above eight measuring points into the following formula to obtain the least square circle center coordinates G(a,b) of the profile of the section to be measured

Step 3. Calculate the roundness error: first calculate the distance between each measuring point and the center of the least square circle, which are R ₀ , R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ and R ₇ , and the calculation formula as follows

Sort the above eight data according to their size, and find the maximum and minimum values among them as R _max and R _min respectively. Then take the least square circle center coordinate G(a,b) as the center, and two concentric circles with R _max and R _min as the radius surround the contour to be measured (due to the actual situation of the measuring point layout, there may be some contours outside the circle), the roundness error is

f _LS =R _max -R _min

It can be seen from the sensor detection principle that when the sensor is arranged, it should be ensured that the axis of the measuring rod is located at the position required by the coordinate system Σ (see Figure 2).

Claims (2)

1. a kind of sebific duct based on minimum two-multiply law withholds performance rating method, it is characterised in that circumferentially equal in space first Eight sensors of even arrangement, when gauge head is located at measurement station, conversion obtains each sensor measuring staff displacement, then calculates each sensor Gauge head measures coordinate during station；Then the Least Square Circle central coordinate of circle of sebific duct buckling piece cross section profile is calculated：Surveyed according to each The coordinate of point draws the Least Square Circle central coordinate of circle of cross section profile to be measured；Last Calculation of Roundness Error：Calculate each measuring point distance The distance in the Least Square Circle center of circle, finds out maximum therein and minimum value, then using Least Square Circle central coordinate of circle as the center of circle, Two concentric circles by radius of described maximum and minimum value obtain deviation from circular from profile to be measured is enclosed in.

2. a kind of realize the device that the sebific duct as claimed in claim 1 based on minimum two-multiply law withholds performance rating method, It is characterized in that：Mainly include cabinet, push-pull electromagnet, Linear displacement transducer, be evenly arranged in spatial dimension inner circumferential Eight Linear displacement transducers and push-pull electromagnet, push-pull electromagnet are each attached to cabinet with Linear displacement transducer main body After cover, the pull bar and Linear displacement transducer measuring staff of push-pull electromagnet are connected；It is linear using push-pull electromagnet driving Displacement transducer measuring staff actively presses buckling piece section to be measured, so that Linear displacement transducer voltage signal data be collected Position machine carries out subsequent treatment, and sensor output signal is 0-100% input direct voltage values, and voltage change becomes corresponding to displacement Change.

Start before detection, transducer probe assembly is located at initial position, now distance is minimum between each gauge head；Then push-pull electromagnet is given It is powered, drives Linear displacement transducer measuring staff to move backward, be put into workpiece to correct position；Electromagnet is powered off again, is now sensed Device gauge head contact measured section, measurement data is that voltage signal reaches host computer by serial communication capture card and calculates section Size and deviation from circular from and provide whether qualified indicate.