RU2353500C2 - Centre hole grinding method using internal grinding device - Google Patents

Abstract

FIELD: engineering industry.

SUBSTANCE: invention refers to precision engineering industry, and can be used when manufacturing electrical spindles and pneumatic spindles. Centre holes of electric spindle shafts are ground using internal grinding device that is provided with rigid prismatic supports located on a turn plate, a limit stop influencing the detail end surface, a spring-loaded limit stop located above the detail, and a head with a grinding wheel. Electric spindle shaft is located horizontally along the outer surface, and two necks thereof are located on rigid prismatic supports of the device. Rotation about its own axis is transmitted to electric spindle shaft. Axial movement thereof along the axis is restricted with the limit stop influencing the end surface, and deflection thereof from rotation axis - with a spring-loaded limit stop.

EFFECT: providing exact location of centre holes relative to base outer surface of electric spindle shaft, which creates conditions for improving accurate operation of circular grinding machines.

23 dwg

Description

The invention relates to the field of precision engineering. It arose in the production of electric spindles and pneumatic spindles, can be used in machine tool, electrical and aviation industries.

Known center grinding machines containing a vertically arranged bed, a device with a center device for installing parts that moves along the guides of the machine bed, a rest for installing parts parallel to the guides of the machine bed, a grinding spindle, a steering mechanism for dressing the grinding wheel at an angle of 45 ° -120 ° .

The objective of the invention: grinding center holes on a multifunctional device for internal grinding (patent No. 2287420), performing similar work in a horizontal way, not inferior in quality, which is achieved as a result of round grinding on a circular grinding machine.

The part with respect to the grinding wheel is at an angle of 30 °, grinding is carried out with a straight profile wheel.

In the course of patent research on scientific, technical and patent literature, no sources similar to the one proposed were found. In accordance with the above, we can conclude that it meets the criteria of "novelty" and "significant differences".

Grinding of the shaft’s inner bore on the internal grinding apparatus is carried out in order to obtain a certain size and the exact location of the inner bore relative to the base outside diameter.

Grinding the center hole on the device for internal grinding is a technological measure that ensures the accuracy of the location of the center holes in relation to the base outer surface, and thereby provides the highest accuracy during round grinding, which allows you to simultaneously maintain precision parameters by the non-circular shape of the outer diameter of the necks of the spindle shaft in limits 0,0002-0,0005 microns. or 2-5 nanometers, and the beating of the necks of the spindle shaft within 1-2 microns.

The center holes polished in this way are located on the base center line, which makes it possible to increase accuracy during circular grinding.

These technological activities are moving into the field of nanotechnology.

The device is presented in the drawings where:

- figure 1 is a General view of the device;

- figure 2 is a top view of figure 1;

- figure 3 is a top view of figure 1 with a device located at an angle of 30 ° with respect to the guides of the machine frame;

- figure 4 - node a of figure 1;

- figure 5 is a section along BB of figure 4;

- figure 6 is a section along BB-5;

- Fig.7 is a section along G-D of Fig.6;

- in Fig.8 is a section along DD of Fig.4;

- figure 9 - node E of figure 5;

- figure 10 is a section FJ of figure 9;

- figure 11 is a section FJ of figure 9;

- in Fig.12 - section FJ of Fig.9 at an angle of 30 °;

- Fig.13 is a perspective view of the device.

The submitted photographs reflect the verification process of the work performed (completed).

The device consists of a plate 1, in which guide surfaces 2, 3, 4 are made, along which racks 5 and 6 are moved during the machine setup process, an electric motor 7 with a power of 0.08 kW 1400 rpm to rotate the part 8 using a flexible element in the form bellows 9, sleeve 10 connecting the bellows 9 and the workpiece. The purpose of the bellows 8 is to eliminate the effect of the electric motor 7 on the part 8.

The rack for mounting prisms 11 and 12 consists of three main parts: the base 13, the vertical part of the rack 14 and the eye 18.

A groove is made in the vertical part of the rack, which has two planes 15 and 16 for mounting prisms 11 and 12. On the surface 16 by moving the plate with the flywheel 31, the perpendicularity of the plane of the rack relative to the guides of the bed (machine) of the device is checked. On the surface of the groove 15, the accuracy of the coaxial arrangement of the vertical part of the rack relative to the guides of the device bed is determined. The vertical part of the rack 14 is connected to the base 13 by bolts 17. In the vertical part of the rack, an eye 18 is fixed, which is rotatable to install the part 8 on the prisms 11 and 12, on a pin connecting the parts 14 and 18. In the eye 18, a spring-loaded stop 19 is installed, holding the part in the axis of rotation during processing. The eye 18 is pressed against the vertical part of the rack by a bolt 20.

The rack on the guide surfaces 2-4 is fixed by a bolt 21 located at an angle of 45 degrees.

The prism consists of two symmetrical parts 11 and 12, which allows grinding them with high accuracy. The working surfaces of prisms 38 can be equipped with VK8 alloy or other material having a low coefficient of friction and high wear resistance (wear resistance). The working surfaces of the prisms can have the same or different angles depending on the type of work performed. Prisms are made from st. 45 and after heat treatment have a hardness of LDC 38-42 units. After preliminary grinding, the plate 38 is surfaced on the working surface of the prism, followed by the final grinding of the prisms and the working surface.

In the process of setting up prisms 11 and 12 are fixed to the plane 16 by bolts 22.

An indicator depth gauge determines the height difference between the axes of the part 8 and the grinding wheel 24. The difference is determined by the thickness of the adjustment plate 25.

A magnetic stand with an indicator head is mounted on the split headstock 26. The flywheel 23 moves the table along the guides of the machine bed, which allows you to determine the position of the part 8 in the vertical and horizontal planes relative to the guides of the machine bed. The accuracy is fixed by the indicator at the moment of touching the surface of the part 8. Thus, it is possible to obtain close parallelism to the axis of the part with the cutting line of the grinding wheel 24.

The base of the headstock 27 is installed on the table of the device 28, which has the ability to reciprocate along the guides of the frame of the device. An electric spindle 29 is installed in the split headstock 26, the protruding diameter of which checks the accuracy of the electric spindle installation relative to the guides of the machine bed with a magnetic stand with an indicator head, which is placed on the plate 1. The table 28 is moved by the flywheel 23, which allows the electrospindle to be installed in horizontal and vertical planes relative to guides of the machine bed. This allows the cutting line to most closely match the guides of the machine. Bolts 32 fix the position of the split headstock 26 on the base 27.

The spring-loaded stop 19 is placed in the eyelet 18 and serves to limit the movement of the part in diameter (eliminates the possibility of beating of the part when it rotates during processing).

The restriction of the movement of the part along the axis during the grinding process eliminates the stop 33, which has a carbide tip 34. The stop can be mounted on a prism depending on the design of the workpiece. The stop is fixed on the side and end surfaces with the help of a thread 35 cut in the prism and a bolt 36, which fixes the stop to the prism. Along axis 37, the plate is rotatably mounted for grinding conical holes. The largest turning angle of the plate is 30 degrees. The device is equipped with a bed 39 with guides and a device 40 for dressing the grinding wheel.

The device operates as follows.

In racks 5 and 6, prisms 11 and 12 are installed, which correspond to the diameter of the part 8. Under the prisms 11 and 12, adjust plates 25 are placed corresponding to the given diameter of the part. Racks 5 and 6 are fixed with bolts 21 on the guide planes 2-4.

The accuracy of the installation of part 8 is checked with a magnetic stand with an indicator head 30 mounted on a split headstock 26. Using the flywheel 23, the table 28 is moved along the guides of the machine bed. On the upper part of the part determine its position in the vertical plane, and on the side surface - the position of the part in the horizontal plane. An emphasis 33 is mounted on one of the prisms, restricting the movement of the part along the axis. The rack with the electric motor is installed and secured in such a way that the bellows 9 operates in compression or tension. Part 8 is connected to the bellows sleeve 10, in which the thread for the bolt (screw), with which the part is connected to the motor. The part mounted on the prisms 11 and 12 is fixed in the working position by a bolt 20.

Dressing of the grinding wheel 24 is carried out by the device 40 with a diamond pencil. Grinding of the hole of the part is performed by reciprocating movement of the table, an increase in the size of the polished diameter of the part is carried out by transverse feeding by the flywheel 31.

To eliminate the taper of the polished surface of the part, a mechanism is used to fine feed the angle of rotation of the part 41 with an indicator head of the ICh-10 type. Cutting fluid (coolant) is supplied to the working surfaces of the prism, which reduces the friction coefficient between the part and the surface of the prisms, protects the part from abrasive dust in the air, and reduces the temperature at the point of contact between the part and the prisms.

The design of the prisms, the guide surfaces of the plate, the base and the vertical part of the rack are rectangular in shape, which allows for flat grinding during the final processing, i.e. in the manufacturing process of parts there are no fastening forces that change the shape and position of it in the device. In this case, parallel and perpendicular planes can be ground with a minimum error of one or two micrometers (0.001-0.002 mm). During assembly and installation, the parts are adjusted to the base and base vertical planes of the rack in such a way that the prisms are mounted to ensure that the axis of the workpiece is deflected in the horizontal and vertical planes from the electrospindle axis to 0.01 mm.

The accuracy of the installation of the workpiece in the cartridge and rest is checked by rotation of the part, i.e. each workpiece is installed (centered) on the base surface of the outer diameter relative to the axis of rotation of the headstock cartridge. On the accuracy of installation of each part spent auxiliary time.

Grinding on prisms allows you to reduce the time for auxiliary operations on the installation of each workpiece, i.e. in the process of setting up the machine for a batch of parts, it is checked that the axis of the workpiece coincides in the vertical and horizontal planes relative to the axis of the electrospindle once for the entire batch.

The grinding process of the center hole is performed in the following sequence.

The plate with the device is deployed at an angle of 30 °, for this operation the following actions are performed. The fine feed mechanism of the part turning angle allows you to rotate the part located on the prisms of the device at an angle of 30 °, for this purpose the machine has a scale of the device turning angle along the axis 37, the nut of the fine feeding mechanism is loosened, the bolt of the fine feeding mechanism of the turning angle is moved along groove 42 parts, after a turn, the nut of the fine feed mechanism is tightened.

The mechanism 40 for dressing the grinding wheel is straightened grinding wheel straight profile, rotating at a speed of 36000 rpm, while the headstock 26 is moved with the spindle by reversing the table from the hydraulic system of the machine or manually using the handle 23 to move the table with the spindle along the guides of the machine bed.

12 shows the location of the part and the grinding wheel during grinding of the center hole.

Photo 1 and photo 2 show the actual grinding process of the center hole.

The headstock with a spindle and a rotating grinding wheel is manually brought in by the handle 23 until it contacts the rotating shaft on the prisms of the device. The movement of the part relative to the grinding wheel, the grinding process occurs due to the movement of the part with the device turned at an angle of 30 °, the transverse feed mechanism 31. Mortise grinding occurs, during grinding the table with the grinding wheel moves manually. After 5-10 seconds of grinding with the handle 23, the grinding wheel is removed from the center hole. The grinding process of the center hole is completed.

Figure 11 shows the grinding of the center hole with a conical grinding wheel. Grinding with a taper grinding wheel requires an additional mechanism for dressing the grinding wheel at an angle of 30 °, grinding the center hole in this way gives ring grooves, to this is added the difference in cutting speed on the large and small diameter of the center hole.

Grinding of a center hole with a taper grinding wheel loses in quality and performance to grinding a center hole with a straight profile.

Checking the runout of the center holes relative to the necks of the electrospindle shaft is performed on the KARL ZEYS device.

Photo 3. General view of the Karl Zeiss device.

An electrospindle shaft is placed on the prisms of the device, a ball is placed in the center hole, which rests on the stop intended for this purpose, a runout of the center hole is checked at the opposite end of the shaft. This method of verification allows you to set a reliable value for the beating. The rotation of the shaft during the inspection is done manually.

The runout check is carried out by an IRPV type 1 minicator of accuracy class. The division price is 1 micron. Range of measurement is ± 40 microns.

Photo 4. Checking the runout of the center hole relative to the necks of the spindle shaft.

Photo 5. Special emphasis restricting the movement of the electrospindle shaft along the axis, and a ball placed in the center hole.

The performed verification shows that the ground center holes are located on one straight line with a deviation from the outer surfaces of not more than 0.002 mm.

The center holes of the shaft, polished in this way on the device for internal grinding from the base of the outer diameter of the part, are parallel to the axis of the part and, thus, create a high-quality technological installation base, which is the key to high accuracy during circular grinding on a circular grinding machine.

There is an effect of the properties of the base of a rotating body when only the vertices of the center hole, which are located on the same axis, participate in the grinding process. Due to the combination of these favorable circumstances, the final grinding on the technological installation base created in this way creates the conditions for increasing the accuracy of the circumference of the polished shaft surface. The non-circular shape of the polished surface does not exceed 0.0015 mm. The runout of the necks of the spindle shaft does not exceed 0.002 mm.

Checking the beating of the necks of the electrospindle shaft relative to the center holes is performed on the PB-500 device (a device for checking the beating in the centers).

Photo 6. General view of the PB-500 device.

Photo 7. Checking the runout of the front neck of the spindle shaft,

Photo 8. Checking the runout of the rear neck of the electrospindle shaft.

The check of the beating of the necks of the electrospindle shaft in the centers on the PB-500 device is carried out by the 05 IMPU mixer. The division price is 0,0005 mm. 1 class of accuracy. Range of measurement is ± 25 microns. GOST 14712-79.

Checking the shape of the center hole on the Talerond instrument shows the faceting of the center hole. The height of the scallops does not exceed 0.001 mm.

Photo 9. A circularogram of the front center hole.

Photo 10. A circularogram of the rear center hole.

The final grinding of the electrospindle shaft at such a center hole makes it possible to obtain a non-circularity of the shaft neck up to 0.0015 mm.

The method of grinding the center holes on the device for internal grinding adds an additional function to be performed on a specialized machine, and the machine has an additional organizing function, which increases the accuracy of the geometric shape of the surface of the part polished on a circular grinding machine.

Grinding the center hole is done on a pre-polished shaft surface. Center holes are ground twice after the first preliminary grinding and artificial aging and after the second preliminary grinding and artificial aging, immediately before the final round grinding.

A simple and productive method of grinding the center hole, in which the part itself becomes the main part - the electrospindle shaft, allows you to grind (create) a high-quality technological installation base on the device for internal grinding. The technological installation base (TUB) created in this way creates conditions that can improve the accuracy of the circular grinding machine, which increases the competitiveness of manufactured products.

Claims (1)

The method of grinding the center holes of the shafts of the electric spindles on the device for internal grinding of parts having rigid prismatic bearings located on the turntable, a stop for acting on the end face of the part, a spring-loaded stop placed on top of the part, and a headstock with a grinding wheel, which consists in the fact that the shaft of the electrospindle base in a horizontal position on the outer surface with the location of its two necks on hard prismatic supports, report the rotation of the shaft of the electrospindle around its own axis and ogre -limiting its axial movement along the focus axis, acting on the end face, and its deviation from the axis of rotation - a spring-loaded abutment with providing accurate positioning holes pivot relative to the base of the outer surface of the shaft electrospindle.

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