RU2324577C2 - Method of bearing insert thickness measurement - Google Patents

Abstract

FIELD: technological processes.

SUBSTANCE: method includes measurement of wall thickness along insert circular arc at least in two cross-sections along insert width at the distance of 5-8 mm from the side butts. In order to improve output and working accuracy, measurement is done on the diamond boring machine in the process of insert internal surface fine boring. Deviation of wall thickness is monitored by means of three inductive shift transducers, which are installed in the casing of machine spindle head along circular axis at the angle of 75°. At that cutting tool wear is monitored by means of photodetector that measures radiation bundle, which is directed to its cutting edge, and wear value is used for determination of bearings wall thickness and for additional tool tuning.

EFFECT: increases capacity and working accuracy.

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Description

The invention relates to instrumentation and can be used to control the parameters of the bearings of the bearings directly in the manufacturing process.

A known device for measuring the geometric parameters of the bearings of the bearings (SU 1758404 A1, G01В 5/02, 1992), containing the base, the base support and the bracket mounted therein and an indicator mounted on the bracket, a through transverse groove is made in the bracket, the device is equipped with a in the groove and mounted on the bracket with the possibility of a fixed rotation about its axis with an equal arm beam, one shoulder of which is designed to interact with the indicator rod, and mounted on the other arm of the beam Yelnia tip with a spherical end face designed to interact with the surface of the measured chamfer insert and the base abutment is rigidly fixed to the bracket by the probe.

The known device does not allow to control the thickness of the liners in the process of their manufacture.

The closest analogue is a device for controlling the dimensions of parts (SU 1441159 A1, G01В 5/02, 1988), which contains a base, a rack with a bracket fixed to it, a reading unit fixed to the bracket, and a support unit designed to interact with the controlled part, in order to improve the accuracy of measurement and simplify the design when measuring the radial thickness of the bearings of the bearings, the support node is made in the form installed with the ability to move in a direction perpendicular to the base, the guide with th slot, perpendicular to the base, spring-loaded in the same direction, and placed in the slot of the rod, one end of which is fixed on the base, the other is made spherical and designed to interact with the controlled part, and the reading unit is made in the form of a shaft mounted coaxially and pivotally mounted with the possibility of swing along the guide of the measuring lever with a spherical tip designed to interact with the controlled part.

The disadvantage of this device is that the control of the thickness of the liners is carried out not in the production process, but after their manufacture using remote control tools.

EFFECT: increased productivity, prevention of defects and increased accuracy of processing of inserts by measuring the thickness of inserts directly on a diamond boring machine in the process of thinly boring their inner surface along the antifriction layer and continuous monitoring of wear of the cutting tool.

The technical result is achieved by the fact that in the method of controlling the thickness of the bearing shells, including measuring the wall thickness along the arc of the circumference of the liner, the control is carried out in the process of thin boring on a diamond boring machine in at least two sections along the liner width at a distance of 5-8 mm from the side the ends of its inner surface using the measurement of the deviation of the liner wall thickness from the standard by means of three inductive displacement transducers installed in the casing of the spindle head of the machine along an arc o of circles at 75 ° to each other and control the degree of wear of the cutting tool by measuring photodetector a radiation beam aimed at the cutting edge of the tool.

Figure 1 shows the location of the components of a diamond boring machine; figure 2 shows the boring mandrel of a diamond boring machine; figure 3 is a section aa in figure 1; figure 4 - diagram of a system for monitoring the thickness of the bearing shells; figure 5 - the eccentricity of the liners; figure 6 is a control map of the deviations of the thickness of the liners.

The general layout (Fig. 1) of the diamond boring machine includes a box-shaped bed 1, to which a hydraulic panel 2 and a cylinder 3 of table 4 are connected. Bridges 5 with spindle heads 6 are mounted on one or both sides of the bed 6. Table 4 with attachment processing device 7 lie freely on the guides and move along them along the bed. Moving the table back and forth is limited by adjustable stops 8 and 9.

The processing of the inserts 10 on the machine is carried out by a cutting tool 11 installed in the boring mandrel 12 (figure 2), with the longitudinal movement of the table 4. Loading, clamping, unloading and stacking of the processed inserts is performed manually.

A casing 13 of a boring mandrel is installed on the spindle head 6 (FIG. 2), in which three inductive displacement transducers 14 are mounted at an angle of 75 ° to each other 14. In the through longitudinal grooves 15 of the casing 13, levers 16 are mounted with a possibility of rotation about their axis (FIG. 3). To do this, in levers 16, conical sockets are made on both sides, in which balls 17 are mounted with their hemisphere. They are mounted in their other hemisphere in conical sockets made on the ends of screws 18 screwed into the casing 13. One arm of the lever 16 is designed to interact with the inductive converter displacements 14, and on its other shoulder is fixed a measuring tip 19 with a spherical end face, designed to interact with the inner surface of the measured insert 10.

The control system includes a sinusoidal current generator 20, which feeds the inductive displacement transducers 14, which are connected through analog amplifiers 21-23 to analog-to-digital converters (ADCs) 24-26. In addition, the system contains a radiation source 27, a photodetector 28, the output of which is connected to an ADC 30 through an amplifier 29. Information from the ADC is supplied to a microprocessor device 31, where it is processed according to specified programs and is output to an external device 32 for displaying and controlling the operation of the diamond boring machine.

The essence of the method is as follows.

In the setup mode, the inductive transducers of displacements 14 are set up according to the reference insert, for which the reference insert is placed in the processing tool 7, clamped motionlessly with the clamp 33, and the movements of the inductive transducers are recorded. Then release the reference insert, remove it from the device, install the processed insert in the device 7, make boring of the inner surface of the insert and control its thickness during boring. When this liner 10 is clamped by a clamp 33 (Fig.3) motionless in the tool 7 for processing the liner and using the table 4 is fed into the processing zone. Using three inductive transducers 14 located at an angle of 75 ° to each other and installed in the casing 13 (figure 2), control the deviation of the thickness of the liner from the standard. Information from inductive transducers of displacement enters the microprocessor device 31. In addition, using the radiation source 27, a photodetector 28, an amplifier 29, and an ADC 30, the magnitude of the measured radiation controls the wear value γ of the cutting tool 11 during processing of the insert.

The thickness of the processed liner S _i along an arc of a circle is defined as

where D is the diameter of the outer cylindrical surface of the liner; d is the diameter of the inner cylindrical surface of the liner; ε is the eccentricity (figure 5) (the displacement of the axes of the outer and inner surfaces of the liner relative to each other); α is the angle of the displacement transducers; γ is the size of the tool wear.

The deviation of the thickness ΔS _i = S _et -S _{i of the} processed insert from the thickness of the standard, where S _et is the thickness of the reference insert, is compared with the tolerance δ. If the liner sizes deviate by more than 0.8δ, the machine is shut down.

To ensure the location of the dimensions (thickness S _i ) of the processed inserts within the tolerance, it is necessary to compensate for the shift of the center of the grouping of dimensional deviations due to wear of the cutting tool and thermal deformation by moving the tool towards the surface to be machined, since the dimensional wear of the tool and thermal deformation shift the center of the group of dimensional deviations to the lower limit of the tolerance field.

With thin boring of the inner surface of the inserts to determine the moment of implementation of the tool set-up, the sizes of each machined insert are controlled and, based on a sample of 25 ÷ 50 measured inserts (depending on the size of the inserts), the displacement of the center of the grouping of deviations of dimensions is determined.

и определяют среднеквадратическое отклонениеTo do this, based on the results of the control, a scatter plot of sizes X _n is constructed (Fig.6). Next, we approximate the scatter diagram of the deviations of the liner thickness of the straight line y = c ₀ + cn by the least square method and estimate the parameters c and c ₀ , as well as the values of the centered deviations of the sizes

and determine the standard deviation

where CL is the center line; X ₀ is the reference value of the thickness;

UCL - upper control boundary: UCL = X ₀ + 3δ;

LCL - lower control boundary: LCL = X ₀ -3δ;

σ is the true standard deviation;

- оцененное стандартное отклонение;

- estimated standard deviation;

UTL - upper limit value of the controlled parameter;

LTL - lower limit value of the monitored parameter;

n is the sample size;

δ = UTL -LTL - thickness tolerance;

X _n - deviation of the thickness of the liners.

сравнивается с истинным стандартным отклонением σ. При этом оцененные стандартные значения отклонений должны быть сопоставимы с истинными.Estimated Standard Deviation

compares with the true standard deviation σ. Moreover, the estimated standard deviation values should be comparable with the true ones.

When the center of the grouping of the deviations of the sizes in the sample is displaced by more than twice the standard deviation 2σ, the value of the adjustment signal is determined for the implementation of tool adjustment by the dependence U _n = k (c ₀ + cn) γ, where k = (0.6 ... 0.8 ) is the coefficient of proportionality.

Thus, according to the information taken using three inductive converters and a photodetector, the deviation of the thickness of the inserts from the thickness of the reference insert during the boring of the inner surface of the inserts is judged, the wear value of the cutting tool and the value of the adjusting signal by which the tool is shifted are determined. Automatic maintenance of dimensions in the middle part of the tolerance field eliminates the likelihood of dimensions outside the tolerance field, which greatly improves the accuracy of processing liners.

The operability of the proposed technical solution was tested at JSC "Plain Bearing Plant" (Tambov). The thickness of the bearings of the D-50 engine bearings was controlled during the boring of the inner surfaces of the bearings on the Model 2705 diamond-boring machine. The test results showed that the measurement error does not exceed the measurement error performed on the device for measuring the geometric parameters of bearing shells (STP 365-73 Device control of the radial thickness of the liner), which does not exceed 5%. If the liner thickness deviates above the permissible values, the machine is stopped and the causes of the defect are identified, i.e. this method almost completely eliminates the receipt of defective inserts. In addition, continuous monitoring of the dimensional wear of the cutting tool allows it to be adjusted at the right time.

Claims (1)

A method of controlling the thickness of bearing shells, including measuring the wall thickness along an arc of the circumference of the shell, characterized in that the control is carried out during fine boring on a diamond boring machine in at least two sections along the width of the shell at a distance of 5-8 mm from the side ends of its inner surface using the measurement of the deviation of the liner wall thickness from the standard by means of three inductive displacement transducers installed in the casing of the spindle head of the machine along an arc of a circle at an angle of 75 ° dr ug to a friend and control of the degree of wear of the cutting tool by measuring the photodetector of a beam of radiation directed at the cutting edge of the tool.

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