CN1253287C - Predeformation working method and fixture for bearing non-circular ball track - Google Patents

Abstract

The invention discloses a pre-deformation processing method for a non-circular raceway of a bearing, which relates to a processing method for a non-circular raceway of a bearing. Its steps are: 1. Process the bearing raceway into a circle whose radius is less than or equal to the difference between the base circle radius and the maximum positive offset of the non-circular raceway design of the bearing; 2. A force F is applied to the outer surface of the ring to cause pre-deformation of the outer ring of the bearing. The direction of the applied force points to the axis of the outer ring of the bearing along the radial direction. 3. Use the grinding machine tool to process the bearing outer ring raceway according to the inner circle processing method. The radius of the processed circle is the same as the base circle radius of the designed non-circular raceway of the bearing; 4. Remove the bearing outer ring. force. The clamp (1) is in the shape of a ring, and its inner surface has a protrusion (2) having the same wave number as the lobe of the non-circular raceway of the bearing to be processed. The invention ensures the smooth transition of the processed non-circular raceway profile and the consistency of product quality, improves production efficiency and reduces cost.

Description

Pre-deformation processing method of bearing non-circular raceway

technical field

The invention relates to a machining method, in particular to a machining method for a non-circular raceway of a bearing.

Background technique

In the past, the non-circular raceway processing of aviation bearings often used the method of CNC grinding. This processing method has the following disadvantages: 1. Due to the reason of the CNC two-dimensional interpolation feed method itself, the contour of the non-circular raceway processed by CNC grinding It is not very smooth, and there is a "step-like" curve, which requires final grinding and polishing, resulting in a change in size; 2. When processing different outer ring blanks, it is difficult to guarantee the consistency of processing quality; 3. Precision CNC machine tools must be used Processing, the cost of production is very high; 4. The processing time is long, can only be produced in a single piece, and is not suitable for mass production.

Contents of the invention

In order to overcome the shortcomings of the CNC grinding method in the processing of non-circular raceways of bearings, ensure the smooth transition of the processed non-circular raceway contours and the consistency of product quality, improve production efficiency and reduce costs, the invention provides a non-circular bearing. Pre-deformation processing method of raceway. The processing method of the present invention is carried out according to the following steps: 1. Process the other parts of the bearing outer ring C except the raceway according to the designed size, and process the bearing raceway into a circle, the radius of which is less than or equal to The difference between the radius of the base circle and the maximum positive offset in the design of the non-circular raceway of the bearing; 2. Apply a force F to the outer surface of the bearing outer ring to cause pre-deformation of the bearing outer ring, and the direction of the applied force points radially to the bearing The shaft center of the outer ring and the part where the force is applied are opposite to the recessed part A of the non-circular raceway designed by the outer ring of the bearing; 3. Use the grinding machine to process the raceway of the outer ring of the bearing according to the processing method of the inner circle, and the processed The radius of the circle is the same as the base circle radius of the designed non-circular raceway of the bearing; 4. Remove the force exerted by the outer ring of the bearing. The magnitude of the pre-deformation δ ₁ generated by the bearing outer ring in the above second step is the difference δ ₂ between the high and low points when the non-circular raceway of the bearing is designed. The jig 1 used for the pre-deformation processing of the non-circular raceway of the bearing of the present invention is a circular ring, and its inner surface has a protrusion 2 with the same wave number as the lobe of the non-circular raceway of the bearing to be processed. The width of the clamp 1 is the same as the width of the processed bearing outer ring. Using the method of the present invention, it is only necessary to design a special fixture, press the outer ring of the non-circular raceway to be processed into the fixture, and apply an external force to the outer ring through the fixture, so that the outer raceway produces the required theoretical profile—this process is called Pre-deformation, and then put the assembled fixture and outer ring together into an ordinary bearing special grinding machine for processing, and grind the non-circular raceway into a circular raceway according to the given grinding amount. The convex part of the blank raceway has more material removed, and the concave part has less material. After the outer ring rebounds, the convex part becomes concave and the concave part becomes convex compared with before exiting the fixture, which is similar to deflecting the original deformation by 60°. The required three-lobe waveform raceway is obtained. The schematic diagram of the principle is shown in Figure 1. The figure shows the change of the raceway profile before and after machining. The raceway profile is represented by the radial offset value relative to the base circle. The invention overcomes the shortcomings of the numerical control grinding method in the processing of non-circular raceways of bearings, ensures the smooth transition of the contour of the processed non-circular raceways and the consistency of product quality, improves production efficiency and reduces costs.

Description of drawings

Fig. 1 is the principle diagram of pre-deformation processing of the present invention, wherein E is the contour of the raceway after pre-deformation, B is the contour of the base circle of the raceway, and D is the contour of the raceway after processing springback; Fig. 2 is the fixture structure of the present invention Schematic diagram, Fig. 3 is the figure picture that processes non-circular raceway profile with Taylor's roundness meter by the method of the present invention, Fig. 4 is the profile picture of the three-lobed non-circular raceway processed by numerical control grinding method.

Detailed ways

This embodiment is carried out according to the following steps: 1. Process the other parts of the bearing outer ring C except for the raceway according to the designed size, and process the bearing raceway into a circle whose radius is less than or equal to that of the bearing. The difference between the radius of the base circle of the circular raceway design and the maximum positive offset; 2. Apply a force F to the outer surface of the bearing outer ring to make the outer ring of the bearing pre-deformed, and the direction of the applied force points to the outer ring of the bearing in the radial direction The shaft center of the bearing, the part where the force is applied is opposite to the recessed part A of the non-circular raceway designed by the bearing outer ring; 3. Use the grinding machine to process the bearing outer ring raceway according to the inner circle processing method, and the processed circle The radius is the same as the base circle radius of the designed non-circular raceway of the bearing; 4. Remove the force exerted by the outer ring of the bearing. The clamp 1 used is in the shape of a ring, and its inner surface has a protrusion 2 with the same wave number as the lobe of the non-circular raceway of the bearing to be processed. The following are three-arc bearing outer rings, raceways and fixtures for pre-deformation processing of 2808 bearing non-circular raceways. The outline dimensions of the non-circular raceway of the 2808 bearing outer ring are shown in Table 1, where the base circle size is Φ52.790mm.

Table 1 The offset of the three-lobed wave raceway of the outer ring of the bearing relative to the base circle (mm) Angle (°) radial displacement Angle (°) radial displacement Angle (°) radial displacement 0 0.02322 130 0.01932 260 0.01007 10 0.01932 140 0.01007 270 -0.00108 20 0.01007 150 -0.00108 280 -0.01127 30 -0.00108 160 -0.01127 290 -0.01829 40 -0.01127 170 -0.01829 300 -0.02078 50 -0.01829 180 -0.02078 310 -0.01829 60 -0.02078 190 -0.01829 320 -0.01127 70 -0.01829 200 -0.01127 330 -0.00108 80 -0.01127 210 -0.00108 340 0.01007 90 -0.00108 220 0.01007 350 0.01932 100 0.01007 230 0.01932 360 0.02322 110 0.01932 240 0.02322 - - 120 0.02322 250 0.01932 - -

Note: The offset of the radial displacement is positive if it deviates from the center of the circle in the radial direction, and negative if it is otherwise.

The outer ring of the fixture is a precise cylindrical shape, and the three arc sections on the inner surface are the contact parts with the workpiece (non-circular raceway ring) during clamping. The specific size of the arc section needs to comprehensively consider the actual protrusion required by the bearing raceway , fixture deformation and contact deformation. In order to use the existing bearing ring grinder, the size of the outer ring of the fixture is set to the maximum diameter that can be processed by the special grinding machine for bearings. Through precise mechanical analysis, the contact arc profile of the three-arc fixture is calculated. The three-arc jig for processing the raceway of the 2808 non-circular outer ring is shown in Figure 2, and the specific deformation dimensions of the arc segments at each position are shown in Table 2.

Table 2: Dimensions of the three-arc fixture for 2808 non-circular outer ring raceway processing (the diameter of the base circle is Φ55.81mm) angle (o) Radial displacement (mm) angle (o) Radial displacement (mm) angle (o) Radial displacement (mm) 30 -0.001 51 -0.020 71 -0.019 31 -0.002 52 -0.021 72 -0.018 32 -0.003 53 -0.0215 73 -0.0175 33 -0.004 54 -0.022 74 -0.017 34 -0.005 55 -0.0225 75 -0.016 35 -0.006 56 -0.023 76 -0.015 36 -0.007 57 -0.023 77 -0.014 37 -0.008 58 -0.0235 78 -0.013 38 -0.009 59 -0.0235 79 -0.012 39 -0.010 60 -0.024 80 -0.011 40 -0.011 61 -0.0235 81 -0.010 41 -0.012 62 -0.0235 82 -0.009 42 -0.013 63 -0.023 83 -0.008 43 -0.014 64 -0.023 84 -0.007 44 -0.015 65 -0.0225 85 -0.006 45 -0.016 66 -0.022 86 -0.005 46 -0.017 67 -0.0215 87 -0.004 47 -0.0175 68 -0.021 88 -0.003 48 -0.018 69 -0.020 89 -0.002 49 -0.019 70 -0.020 90 -0.001 50 -0.020 - - - - 0°～20°, 100°～120° non-contact area Diameter 60mm 20°～30°, 90°～100° transition area smooth transition

Four sets of pre-deformation processing tests were carried out on the raceway of the 2808 non-circular outer ring. Table 3 shows the experimental process records and results of the processing. The maximum roundness error of the non-circular raceway after processing is 2 μm, which is within the allowable precision of 2 μm. Inside.

Table 3 Outer ring blank test results serial number Before grinding after grinding Channel size (mm) Actual measured roundness (μm) Roundness (μm) Grinding amount(mm) 1 52.887+0.22 1.5 2 0.24 2 52.887+0.45 2 2 0.22 3 52.887+0.47 1.5 1.5 0.16 4 52.887+0.19 2 2 0.2

The profile of the non-circular raceway of one group of outer rings exiting the fixture after grinding was measured with a Taylor roundness meter, as shown in Figure 3, and Figure 4 is the profile diagram of the three-lobed non-circular raceway processed by the CNC grinding method. Comparing the two figures, it can be clearly seen that the three-lobed non-circular raceway processed by the pre-deformation method has the same good macro-contour shape as the raceway processed by the CNC grinding method, but the pre-deformation processing is continuous processing, which avoids the The CNC grinding method causes the "stepped" phenomenon of the contour due to the interpolation processing of logarithmic points; the maximum roundness error of the non-circular raceway contour processed by the pre-deformation method is 2 μm, which is within the allowable error range of 2 μm; the outer ring processing The time is short, generally within 5 minutes to process a workpiece, which is suitable for mass production; at the same time, the consistency of product processing is better.

The three-arc fixture used for actual pre-deformation processing in this embodiment is processed by a precision wire-cut machine tool because the three arc sections in the fixture that are in contact with the workpiece are non-circular and cannot be processed by ordinary grinding machines. The width of the fixture is the same as The width of the processed outer ring is uniform.

The pre-deformation processing principle of different types of bearing non-circular raceways is the same, as long as the matching fixture is designed according to the given theoretical contour and outer ring size. For bearings of the same type, due to the tolerance size, the outer surface size of the outer ring varies within a range, and several sets of fixtures can be designed according to the needs, grouped according to the tolerance range requirements, and these fixtures are similar in shape and have slight changes in size (For example, the size of the base circle of the outer ring of the 2808 bearing is divided into several size segments within the tolerance range, and the size of the contacting three-arc segment surface is calculated according to Table 2. Other dimensions remain unchanged, and the fixture can be processed). When grinding the non-circular raceway of the outer ring, first measure the diameter of the outer surface of the outer ring, then select the corresponding fixture, press the outer ring into the fixture in parallel, and process it according to the normal bearing raceway grinding process. Considering the repeated use of the fixture, the material of the fixture can be selected from mold steel with better wear resistance (such as Crl2).

Claims (2)

1. The pre-deformation processing method of the non-circular raceway of the bearing is characterized in that it is carried out according to the following steps: 1. Process the other parts of the bearing outer ring C except the raceway according to the design size, and process the bearing raceway into Circular, the radius of the circle is less than or equal to the difference between the base circle radius of the non-circular raceway design of the bearing and the maximum positive offset; 2. Apply a force F to the outer surface of the bearing outer ring to make the bearing outer ring produce a predetermined Deformation, the direction of the applied force points to the axis of the bearing outer ring in the radial direction, and the position where the force is applied is opposite to the recessed part A of the non-circular raceway designed by the bearing outer ring; The processing method of the inner circle is processed, and the radius of the processed circle is the same as the base circle radius of the designed non-circular raceway of the bearing; 4. Remove the force exerted by the outer ring of the bearing. 2. The pre-deformation processing method of bearing non-circular raceway according to claim 1, characterized in that the pre-deformation amount _δ1 produced by the bearing outer ring in the second step is the height of the bearing non-circular raceway design Spread value δ ₂ .

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