Research On The Verticality Detection Device Of The Main Shaft Nut Thread Of The Locomotive Turbocharger

The diesel locomotive turbocharger is the core component of the locomotive. When the turbocharger is working, its rotor speed is between 30 000 and 40 000 r/min. The core component of the turbocharger is the rotor part, which is mainly composed of the main shaft and the wheel blades. , Bearing sleeve, impeller and spindle nut (see Figure 1). Due to the high temperature and high speed working conditions, the machining accuracy of its rotor parts is also very high. Among them, the spindle nut is the locking and positioning part of the spindle and the impeller. , The end face will be subjected to a lot of pressure during tightening. If the end face is not perpendicular to the thread, it means that the end face of the spindle nut and the connected impeller face are not evenly contacted during tightening, and it is easy to form additional bends on the head of the spindle thread. Torque, which has a great influence on the fatigue strength of the spindle, and even leads to a quality accident of the spindle thread "turning around". The high-speed rotation of the turbocharger rotor will also directly affect the dynamic balance stability of the rotor. Therefore, the design pattern of the spindle nut has strict requirements on the verticality of its end surface with respect to the thread. Because the thread shape of the spindle nut is complex and special, and the thread is in the blind hole of the spindle nut, it is difficult to detect the thread. There are professional thread measurement abroad. Technology companies have launched many professional thread measuring instruments, but there are very few devices that can detect the internal threads of blind holes, and these measuring instruments are expensive to make and the purchase cost is high.

There are some general measuring equipment such as coordinate measuring instrument and optical measuring instrument that also have related thread measurement functions, but they are not professional enough and the accuracy is not high. For example: the three-coordinate measuring instrument establishes the axis by taking points along the spiral groove according to the theoretical pitch, but the probe cannot enter the groove, the measurement accuracy is not high, and the detection process is more troublesome. Optical measuring machines are generally used for the detection of shaft parts with center holes at both ends. The internal thread of the spindle nut cannot be projected and cannot be detected.

1. Design plan and specific implementation of testing device

The verticality detection device of the blind hole thread of the main shaft nut of the locomotive supercharger is shown in Figure 2. This new detection device has the characteristics of simple structure, low cost, simple operation, high detection efficiency and high detection accuracy, which solves the problem of the locomotive supercharger. The problem that the thread perpendicularity of the blind hole of the spindle nut cannot be detected.

Preparation and characterization of electrochemical emulsion polymerization of methyl methacrylate····································································································································································· ··Zhang Jianqiu Fu Lingxiao Chen Long Zhang Shengjia (6,925)

1. Anti-loosening bolt 2. Compression spring 3. Gauge bracket 4. Lever dial indicator 5. Top ball 6. Rotating shaft 7. Base sleeve 8. Base 9. Lock nut 10. Support column 11. Bottom plate 12. Spindle Nut

The method of use of the device is to tighten the spindle nut to the upper thread of the rotating shaft, use the top ball to reach the center of the bottom surface of the blind hole of the spindle nut to ensure that the thread of the spindle nut and the thread of the rotating shaft of the detection device remain freely locked, and adjust the meter bracket to ensure the lever The stylus of the dial indicator is in contact with the measured end surface of the spindle nut, and the stylus is compressed by 0.1～0.2mm, and then the lock nut is rotated to drive the rotating shaft to rotate. The compression spring ensures that the base sleeve and the shaft shoulder of the rotating shaft are kept Close contact, no axial movement, at this time, rotate 360°, the amount of change displayed by the dial indicator can measure the runout of the spindle nut end face. Since the spindle nut end face is an annular belt, the runout is approximately equal to the verticality, which is verified by calculation The error is less than 0.005mm, which can be directly used as the perpendicularity between the thread axis of the spindle nut and the end surface.

2. Precautions for the processing of components of the detection device

The precautions for processing the components of the detection device are as follows:

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(1) The upper end surface of the base sleeve and the inner hole shall ensure that the perpendicularity is within 0.005mm, and the surface roughness value Ra<0.8μm.

(2) The shoulder and outer circle of the rotating shaft should ensure that the verticality is within 0.005mm, and the surface roughness value Ra<0.8μm. The rotating shaft should be ground with double centers, and the upper center hole should be kept intact.

(3) The top ball is selected from the steel ball with a precision of 8mm or above G10, and the top ball is placed in the center hole of the upper end of the rotating shaft during testing to ensure that the top ball is higher than the upper end of the rotating shaft.

(4) The base sleeve and the rotating shaft adopt clearance fit, and the fit clearance is guaranteed to be 0.01～0.02mm.

When testing directly on the finished furniture, the main surface layer in the furniture should be selected, and the surface of the detectable surface is required to be smooth and free of defects such as blisters, scratches, fading, and wrinkles.

3. Conclusion

The detection device for the thread perpendicularity of the spindle blind hole nut of the locomotive turbocharger has the advantages of simple structure, low cost, simple operation, high detection efficiency and high detection accuracy. It uses the top ball to the center of the bottom surface of the spindle nut blind hole to ensure the thread of the spindle nut The thread of the rotating shaft of the detection device is kept in a freely locked state, and one rotation is measured with a dial gauge. The device solves the problem that the thread verticality of the blind hole of the main shaft nut of the locomotive supercharger cannot be detected, and effectively reduces the failure rate of the locomotive supercharger.