1 to ensure the main processing accuracy of the parts It is well known that the accuracy of scroll compressor parts generally requires micrometers (μm) because it has a large impact on compressor performance. The main machining accuracy of the parts is: (1) The accuracy of the vortex line The accuracy of the vortex line is the most important factor affecting the refrigeration capacity of the compressor. It mainly includes the error of the contour profile of the vortex line, that is, the actual value and the theoretical involute vortex (which also forms the vortex line with other line types), the end face of the profile line, the flatness of the bottom surface of the profile line, and the parallel between the two. Degree, vortex wall surface roughness, up and down chamfering value, vortex wall verticality (verticality has been included by the contour of the vortex line, generally not measured in production). The contour of the vortex line should be within 10 to 15 μm, and the flatness and parallelism should generally be controlled within 5 μm. The vortex line accuracy can be obtained from Tosok Corporation's vortex precision line tester. (2) Keyway "Three Degrees" Keyway "Three Degrees" refers to the flatness, parallelism and verticality of the movable plate and the sides of the keyway where the cross slip ring is mounted on the frame. It is the key to affect the running performance of the compressor. It should be controlled within 715μm. It needs to be tested in the measuring chamber with a coordinate measuring machine or in the production line with the special inspection device of MARPOSS. (3) Parallelism and eccentricity of the crankshaft In addition to ensuring the dimensional tolerance of the main shaft diameter and the eccentric shaft diameter, and the cylindricity accuracy of each shaft diameter, the parallelism of the axis of the eccentric portion of the crankshaft and the main axis, and the amount of eccentricity, It can be tested by the special testing equipment of the production line to ensure the good meshing state of the vortex line. (4) Coaxiality and verticality of the frame The main shape accuracy of the frame is the coaxiality between the main bearing hole and the lower bearing hole and the perpendicularity of the two bearing holes to the end face of the frame. It is required to test with special production line testing equipment. To ensure good performance of the spindle. (5) Accuracy of the inner diameter of the casing Regardless of the high pressure chamber or the low pressure chamber scroll type air conditioner compressor, the stator of the motor is thermally housed in the envelope. In order to ensure the uniformity of the rotor air gap, the inner diameter of the housing generally needs to be rough and finely shaped to achieve the required inner diameter accuracy. 3 scroll processing machine and tool 311 processing plane (1) The machining principle of the machine tool has been proved by a large number of practices: it is difficult to machine the high-precision scroll wall (the error is in the micrometer range) by the X and Y-axis circular interpolation of the machining center, and it is only suitable for the rough machining of the scroll wall. . The semi-finishing of the vortex wall can be completed by the development method using a high-precision machining center with a numerically controlled rotary table. For the finishing of the scroll, it must be realized by a special machine. Its machining principle is to use the X, Y, Z, C axis four-axis linkage and closed-loop control, and the involute interpolation based on the expansion method to complete the vortex. The processing of the rotary disc. (2) The main precision of the special plane requires the static accuracy of the special plane to be the basis of the dynamic accuracy of the scroll processing. The main static precisions are: spindle axial runout, radial runout, straightness of X-axis motion, repeated positioning accuracy of X, Y, Z, C axes, and jump of the positioning surface of the workpiece fixture. Dynamic accuracy (refer to the technical data of KY20 special machine provided by Japan kashifuji Co., Ltd.): The involute curve error MIN of the upper, lower, inner wall and lower wall of the vortex wall is -0.0075mm, MAX is 0.0075mm, FORM=MAX- MIN≤0.0125mm, the flatness of the bottom surface of the vortex wall is 0.005mm. (3) The main manufacturers of special planes have been researching the manufacturing technology of scroll compressors since the 1980s. After more than ten years of unremitting efforts, the most One of the key technologies, the DDD scroll rotary CNC Machining machine, has greatly improved the machining accuracy and speeded up the manufacturing cycle, thereby increasing the interchangeability of the parts and greatly improving their economy. Major companies producing rotary scroll processing machines abroad include Excello in Germany, Toyoadvance in Japan, Hitachi seiki, Kashifuji, Mitsuiseiki, and Boston Digital Corporation of the United States. (BostonDigitalcorporation), Switzerland's Willemin and other companies. China has just begun to develop this aspect. Only Qinghai No. 2 Machine Tool Plant has produced a scrolling machine. (4) Basic requirements of the scrolling machine For the finishing of the iron castings of air-conditioner compressors, the rotational speed of the tool spindle is generally 3000-10000r/min, and the precision of the aluminum alloy material for the rotating plate of the scroll-type automotive air-conditioning compressor Processing, such as Japan's Toyo's T-402SCY plane, three tool spindle speeds are 20000, 30000, 40000 r / min, three tool spindles for processing different parts, the output power of each axis is 11,11,715kW For high-speed or ultra-high-speed cutting of thin-walled parts, it is easy to ensure the machining accuracy of the parts, but the moving parts of the machine tool should also be suitable for high-speed movement. The minimum unit of X, Y, Z-axis pulse should be 01001mm, and the minimum rotation of the workpiece rotation C-axis The unit is 01001° (3.6′′); the control system of the machine tool must have RDQ control function, which can realize the processing of the forming method, with the involute interpolation function, which can be used to manually write the vortex line processing program; outside the workpiece chuck The diameter should be smaller than the outer diameter of the workpiece flange by 0102~0.04mm, and the flatness of the positioning surface of the chuck workpiece should be within 3μm. The clamping force of the clamp should have a 2-level conversion function. The final finishing vortex wall clamping force should be adjusted. low To reduce the clamping deformation; the machine tool should be equipped with a constant temperature cooling device and a cutting oil mist collecting device. 312 machining tool One of the most important factors affecting the manufacturing cost of a scroll compressor is a scroll-type line fine milling cutter. The use of these high-precision milling cutters is critical to reducing the manufacturing cost of scroll compressors. (1) Processing tool material and precision requirements The material is solid as a whole Alloy (with special components, good wear resistance), main precision requirements: straightness of cutting edge <3μm; radial runout <3μm; bottom edge runout <3μm; blade taper <2μm; hardness >60HRC; right edge right The rotation angle is 30°; the surface roughness of the cutting edge is Ra0.4μm; the surface roughness of the short toothed belt is Ra0.4μm; the number of teeth is 6. (2) The use of the tool combined with the material to be processed, through repeated Practice, for the semi-finishing of the profile, the finishing of the profile, the cutting parameters (rotation speed and feed rate) of different milling cutters for the finishing of the top surface of the bottom surface should be reasonably selected, so that the life of the cutter is changed once, and the grinding is repeated. After use, in addition, the quality of the tool has a great influence on the life of the milling cutter. The milling shank should be selected as the Japanese BIG high-precision shank. The clamping accuracy of the clamping jaw is AA grade, that is, after each clamping of the milling cutter, the milling cutter protrudes twice the diameter of the milling cutter. The radial runout of the measuring cutter should be within 3 μm. If the radial runout of the milling cutter is greater than 3 μm, the tool wear is increased and the life is shortened. (3) The re-grinding scroll compressor of the tool mainly relies on milling, the milling cutter is expensive, the amount is large, and it is easy to wear. Therefore, not only to re-grind, but also to solve the problem of regrind accuracy. A high-precision milling cutter re-grinding machine should be imported, and a 5-axis CNC tool grinder from Schneeberger, Switzerland can be used. (4) Technical Difficulties While using Japanese special milling cutters, in order to reduce costs, we also tried to replace them with milling cutters imported from other countries. The main problems in use are the inconsistent precision of the cutters, fast wear and short service life. At present, the accuracy of such tools cannot be solved at present, and the tool material is brittle and easy to wear. 3 parts accuracy on-machine detection and off-machine detection 311 on-machine detection (1) On-machine detection of vortex line accuracy Some scroll discs can automatically detect the accuracy of vortex lines after machining the profile line. For example, Japan's Toyo, Kenten's scroll disc plane has this function. (2) Automatic detection of the vortex wall depth grinder The axial leakage caused by the axial clearance of the vortex wall is much larger than the tangential leakage caused by the radial clearance. Therefore, in the control process of production, the depth of the vortex wall should be strictly controlled within a certain range, regardless of the CNC surface grinder for grinding the end face of the fixed plate type, or the numerically controlled rotary grinder for grinding the end face and the end face of the moving plate type. It is necessary to automatically measure the height of the profile with a measuring probe and determine from the measurement data whether grinding and grinding are still required. (3) Crankshaft main journal, eccentric journal grinding in the machine tool industry, CNC internal and external cylindrical grinding machine using MARPOSS in-machine measurement technology has been quite mature. The crankshaft main shaft of the scroll compressor and the numerically controlled cylindrical grinding machine for the eccentric journal also use this technology to ensure stable batch quality. 312 off-machine detection (1) Main precision measuring instruments The main final precision tests of the parts used in the production line require high-precision and rapid testing instruments, such as pneumatic and electrical micrometers (using MARPOSS probes) to ensure the main dimensional tolerance requirements of the parts. (2) Use of special integrated measuring instruments in the production line Due to the development of testing technology, some testing items in the laboratory can also be moved to the production site for rapid testing. For example, Tosokcorpora2 tion's moving scroll type line accuracy tester is used as a test procedure. (3) Three-coordinate measuring machine, the use of the roundness meter uses the high-precision coordinate measuring machine of the measuring room, and the rounding instrument checks the main processing precision of the parts, and is the final judgment of the qualified parts of the parts. The coordinate measuring machine is also used to detect the accuracy of the vortex line, and can also be used as the basis for the operator to compensate the vortex line processing machine. 4 important assembly dimensional tolerance grouping In order to reduce processing costs, improve compressor assembly accuracy and consistency of batch machine performance, like piston and rotary compressors, scroll compressors also require a group assembly process. (1) The outer diameter of the eccentric sleeve and the inner diameter of the needle bearing are selected in the scroll type automotive air-conditioner compressor. The drawn outer ring needle roller bearing is pressed into the bearing hole of the moving disc, and the tolerance of the inner diameter of the needle bearing after pressing is The range is large. In order to obtain good compressor performance, the tolerance of the inner diameter is divided into six groups, and the outer diameter of the eccentric sleeve is matched with it to ensure that each group has the same gap value. (2) Type line depth pairing group If the type line does not adopt the end face sealing technology, the moving plate type line depth must be grouped and paired, each group of 3~5μm, divided into 5~6 groups, the same group fixed type The line depth is 5μm deeper than the dynamic disk type. It can also be completed by mass measurement grouping machine in mass production. (3) After assembling the thickness of the moving plate end and the mechanism of the frame grouping scroll compressor, it is required to manually confirm the axial clearance of the crankshaft, the rotation should be smooth, and the axial direction can be slightly moved. Therefore, the rear plate surface of the moving plate assembly is lower than the end surface of the frame, generally 5 to 25 μm. Since the thickness of the moving plate end plate is difficult to control, in order to ensure the above height difference, the thickness of the moving plate end plate and the frame are assembled in groups. 5 automatic centering device when the mechanism department is assembled The scroll compressor with a radial flexible mechanism, the optimal meshing position of the fixed scroll can be positioned by rough positioning and then using the positioning pin (the positioning accuracy also reaches the allowable value), and the eccentricity of the crankshaft can be operated during operation. The fine-tuning method (ie, the radial flexible mechanism) ensures good meshing under the action of centrifugal force, and therefore, a high-precision automatic centering device is not required. However, for a scroll compressor with a constant crankshaft eccentricity, it is necessary to accurately find the optimal meshing position of the movable scroll and the fixed scroll when assembling the mechanism. The principle of the automatic center-finding device is: in order to smoothly operate between the parts of the mechanism part mounted in the compressor frame, the parts need to run together; firstly, the sensor is used to detect the pressure of the exhaust port during the dry running, and then the crankshaft is tightened. Slowly rotate, the compressor rotates side, the workpiece pressure plate gently presses the fixed plate from the upper part, and the fixed plate generates a slight movement under the engagement of the moving plate, so that the center of the fixed plate type is accurately positioned to the frame, and then The bolts are tightened symmetrically. Finally, the torque detector is used to check whether the positioning of the fixing plate is accurate, and whether the load of the internal parts of the compressor is correct. Finally, it is confirmed by hand that the crankshaft is running smoothly and there is no dead point. 6 chamfering, the impact of deburring process on compressor performance 611 chamfering due to the fine milling of the vortex wall and the milling cutter on the bottom surface will have a small nose radius, so the bottom of the vortex wall will be chamfered, generally required R <0. 2mm or C <012mm; moving, fixed vortex wall The chamfer is matched with the paired and the lower chamfer of the movable scroll wall. If the chamfer is not milled, the compressor power will increase by 100~150W. Therefore, the finishing of the scroll wall must be finished. The upper chamfering is required to be 0.02 to 0.25 mm, and it is necessary to use a shape measuring machine to amplify and measure the chamfering value. 612 deburring (1) Rack deburring process We have conducted a test analysis on the degree of influence of the rack deburring process on the performance of the compressor. The test proves that the rack "patterned surface" ("patterned surface" is the casting oil groove, the contact surface between the moving plate and the frame, the contact surface of the cross slip ring and the frame is called the "pattern surface") after the deburring process The average input power of the compressor will drop by 90W, the cooling capacity will increase by 33W, the coefficient of performance (COP) will increase by 01062W/W, the noise will decrease by 01588dB(A), and the vibration will drop by 01175m/s2. In addition, the number of units in the organization department with dead points and downlines has also been greatly reduced. Deburring method: Use an abrasive nylon brush to rotate the brush on the bench drill to interrupt the cutting edge burrs of the groove. (2) Fixed plate deburring process The end face of the plate is composed of a bolt seat surface, a sealing surface and a profile end surface, which are separated by an annular oil groove. The oil tank is made of a car. After milling, it needs a fine grinding plane, which will inevitably produce burrs. If the burr is not removed, it will cause great hidden troubles. Therefore, it is necessary to use a nylon brush with abrasive to rotate the surface of the fixed plate on the bench drill. glitch. (3) Crankshaft deburring process The crankshaft also passes through the car and grinding process, which will cause edge burrs. When manufacturing, use special deburring equipment (such as Japan Xindong) with abrasive brush, wire brush to remove the outer surface of the crankshaft, and the burr of the oil suction hole. And high frequency quenched scale. 7 Influence of phosphating on the reliability of compressor (1) The purpose of phosphating is to prevent axial leakage of the scroll wall. When the moving plate is translated, the intermediate pressure on the back side of the moving plate is pushed to the fixed plate side (high pressure chamber structure), or in the back pressure chamber. Under the action, the fixed plate is pushed to the moving plate side (low pressure cavity structure), and the friction is large. If the moving plate, the fixed plate or the fixed plate is made of manganese phosphating (phosphorylated film is generally 3~12μm), since the phosphating film has oil storage function, the initial aptitude is good after the phosphating treatment. It does not cause abnormal wear and is also beneficial to the starting performance. (2) Phosphating process parameters and orthogonal test methods The process parameters to be controlled by phosphating are: total acidity, free acidity, iron content, acid ratio, phosphating temperature and time. For scrolls of the same material but different materials but different foundries, the film thickness of the phosphating may be different under the same phosphating process parameters. Therefore, according to different materials, the orthogonal test method of statistical techniques can be used to find the process parameters suitable for different materials through multiple sets of tests. (3) Inspection of phosphating film 1 Appearance: uniform, dense, gray or black, no phosphating residual blank or rust on the surface; 2 film thickness: 3~12μm, no more than 15μm, using magnetic measurement Thickness gauge measurement; 3 Corrosion resistance: 3% sodium chloride solution, taken after 2 hours, no rust on the surface is qualified. The later the rusting time occurs, the better the corrosion resistance of the phosphating film. 8 performance test and life test (1) Performance test 1 comprehensively reflects the level of compressor manufacturing. Under the premise of a certain structural design, it is impossible to test the performance of each compressor at the same value. It reflects the accuracy of the compressor parts, the manufacturing level of the motor and the quality of the assembly. 2 Use the performance test data to analyze the problem. By testing the compressor's cooling capacity, input power, vibration, noise, and data analysis of the motor winding temperature, problems with the compressor can be found to further improve the design, improve the manufacturing process, and continuously improve compressor performance. (2) Life test The accelerated life test is to judge whether the service life of the same batch of compressors meets the design requirements by performing 500h or 1000h work under the most severe working conditions. This is the durability and reliability test content of the compressor. It is the most effective type test method for judging compressor design, manufacturing process and material change. 9 Conclusion Through eight aspects of the discussion, it is necessary to solve the above several key technical problems in mass production to ensure the production of stable and high quality scroll compressors. The main conclusions are as follows: (1) The machining accuracy of the parts, especially the accuracy of the vortex line, is crucial to the performance of the compressor. (2) The process equipment technology for the mass production of scroll compressors is quite mature; (3) Parts accuracy test And performance testing is the necessary means to ensure the quality of the compressor; (4) scroll compressor without radial flexible mechanism, the key technology of the assembly of the mechanism is the dynamic, fixed scroll automatic centering device; (5) chamfering The deburring process has a great influence on the performance consistency of the scroll compressor, which can greatly improve the performance; (6) the surface treatment of the parts is one of the key technologies to ensure the reliability of the compressor. Construction Scaffolding Parts
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