Method for controlling clamping deformation of wheel disc type part by using dial indicator

Abstract

The invention provides a method for controlling clamping deformation of wheel disc type parts through a dial indicator, and relates to the technical field of machining. Comprising the following steps: setting measuring points at a plurality of clamping parts on the outer wall of the wheel disc type part, correspondingly installing a dial indicator at each measuring point, pre-processing, calculating a clamping deformation coefficient, calculating the maximum theoretical allowable reading of the dial indicators, determining the maximum allowable clamping deformation of the part during formal processing, and calculating the clamping deformation of the dial indicators during formal processing. According to the invention, a mature precision measuring tool dial indicator in the field of machining is used for monitoring tiny deformation of the surface of the part, deformation data is converted into a clamping force regulation basis, accurate control of clamping deformation is realized, and the method has the characteristics of high machining precision, low equipment cost and high universality.

Description

Technical Field

[0001] This invention relates to the field of machining technology, specifically to a method for controlling the clamping deformation of disc-type parts using a dial indicator. Background Technology

[0002] Currently in the field of machining, medium and large-sized disc-shaped parts are particularly important due to their large size, heavy weight, complex structure (some being hollow, thin-walled structures), and high precision requirements (e.g., diameter tolerance ≤ 0.07mm). Controlling clamping deformation during machining is crucial. Insufficient clamping force can easily lead to displacement or vibration during machining, while excessive clamping force can cause plastic deformation, both of which reduce machining accuracy. (The text then abruptly shifts to a seemingly unrelated topic about diameter tolerances.) Taking a 100mm aluminum alloy resolver bracket as an example, the clamping deformation error caused by traditional hydraulic clamping methods is ≥0.11mm (11 microns), far exceeding the tolerance requirements and easily resulting in scrap. The clamping force required for medium and large-sized rotary disc parts varies significantly depending on the material and specifications. In existing technologies, the clamping fixtures for medium and large-sized rotary disc parts are mostly bulky structures (such as a single set of vertical lathe clamping clamps weighing over 50kg), requiring manual adjustment of the jaws with a 500mm long wrench. This can easily cause over-clamping of thin-walled parts, further exacerbating the deformation problem. Therefore, it is evident that because traditional clamping methods cannot control the clamping force through data, the clamping deformation of medium and large-sized rotary disc parts is difficult to control.

[0003] Existing technologies have attempted to monitor part deformation using strain sensors and pressure sensors to adjust clamping force, but these still suffer from two major limitations: high cost and narrow applicability. A complete sensor system (including the sensor body, data acquisition module, and adaptive control software) costs over 10,000 yuan and requires regular calibration every three months, resulting in high maintenance costs. On the other hand, sensors have strict requirements for installation space and are prone to insufficient installation space due to clamping jaw obstruction. Furthermore, their accuracy is affected by processing temperature (such as ambient temperature fluctuations of ±5℃ caused by cutting heat), making it difficult to meet the high-precision clamping requirements of medium to large-sized disc-shaped parts. Summary of the Invention

[0004] To address the problems and shortcomings of existing technologies, this invention provides a method for controlling the clamping deformation of wheel-type parts using a dial indicator. By using a dial indicator, a mature precision measuring tool in the field of machining, to monitor minute deformations on the surface of the part, the deformation data is converted into a basis for adjusting the clamping force, thereby achieving precise control of clamping deformation.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for controlling the clamping deformation of disc-shaped parts using a dial indicator, comprising the following steps: S1. Measuring points are set at several clamping locations on the outer wall of the wheel-type part. Each measuring point corresponds to a dial indicator, and the dial indicator is fixed on the base of the clamping fixture, with the measuring head of the dial indicator in perpendicular contact with the measuring point. S2. Set the same preload for each measuring head, and after the dial indicator pointers stabilize, return all dial indicator readings to zero. S3. Calculate the actual deformation of the part corresponding to the unit percentage gauge deformation, i.e., the clamping deformation coefficient E: S3a. The measuring points include several fixed measuring points and several initial adjustment measuring points, and the fixed measuring points and the initial adjustment measuring points are arranged opposite each other in pairs; S3b. First, pre-tighten the clamping fixtures corresponding to all fixed measuring points, and then pre-tighten the clamping fixtures corresponding to the initial adjustment measuring points in sequence, so that the dial indicator index corresponding to all initial adjustment measuring points is stable at the clamping deformation amount A1; the clamping deformation amount A1 is less than the lower tolerance of the diameter of the wheel-type part. S3c. Perform trial machining on the wheel-type part along the outer circle direction and leave machining allowance. After the trial machining is completed, measure and calculate the average diameter of the part in the clamping state at all initial adjustment measuring points as B; remove the part, measure and calculate the average diameter of the part in the non-clamping state as C, and calculate the deformation parameter D1=|BC|. S3d. Re-clamp the wheel-type part and increase the clamping force to stabilize the dial indicator index corresponding to all initial adjustment measuring points at the clamping deformation amount A2. Repeat step S3c and calculate the deformation parameter D2. The clamping deformation amount A2 is less than the lower tolerance of the diameter of the wheel-type part. S3e. Calculate the clamping deformation coefficient E=(D2-D1) / (A2-A1); S4. Based on the dimensional tolerance requirements of the wheel-type parts and the clamping deformation coefficient E, calculate the maximum theoretical allowable reading H of the dial indicator = lower tolerance of the part diameter / E; S5. Based on the reserved machining allowance, determine the maximum allowable clamping deformation D0 (D0 < H) during the formal machining of the part, and calculate the clamping deformation A = D0 / E during the formal machining; S6. Re-clamp the wheel-type parts and adjust the clamping force so that the dial indicator readings corresponding to all initial adjustment measuring points are stable at the clamping deformation amount A.

[0006] Furthermore, the number of measuring points is 4, 6, or 8, and they are evenly distributed along the outer circumference of the wheel-like part.

[0007] Furthermore, the measuring point is located in the thin-walled region where the wheel-like part has relatively weak rigidity.

[0008] Furthermore, the dial indicator is mounted on the base of the clamping fixture via a magnetic base or a fixed holder.

[0009] Furthermore, the clamping deformation A1 is one-third of the lower tolerance of the part diameter, and the clamping deformation A2 is two-thirds of the lower tolerance of the part diameter.

[0010] Furthermore, after trial processing, the diameter of the part is measured using an outside micrometer in the clamped state, and in the non-clamped state, the diameter of the part is measured using a coordinate measuring machine.

[0011] Furthermore, the wheel-type parts are thin-walled disc-type parts with a diameter ≥300mm, a weight ≥10kg, and a hollow center.

[0012] Furthermore, the clamping fixture is a clamping clamp for a vertical lathe, and its clamping force is manually adjusted by a clamping force adjusting bolt.

[0013] This invention provides a method for controlling the clamping deformation of disc-shaped parts using a dial indicator, which has the following beneficial effects: 1. Significantly improved clamping accuracy. For example, for diameter... For aluminum alloy resolver brackets with a diameter of mm, the clamping deformation error range of traditional hydraulic clamping method is ≥0.11mm (11 microns). Under the same conditions, the clamping deformation error is ≤0.06mm (6 microns), improving the clamping accuracy by about 45%, effectively avoiding the scrapping of parts due to deformation, and increasing the processing qualification rate from 0% to 100%. 2. Significantly reduced equipment costs. Dial indicators are economical and require no additional maintenance. Compared to clamping force control systems using sensors, they reduce equipment costs by more than 99%. At the same time, they avoid the limitations of sensors being affected by installation space and temperature, and are suitable for clamping various medium and large-sized disc-shaped parts. 3. Strong adaptability and versatility. This invention relates to the differences in material, structure and specifications of parts through the "deformation coefficient E". There is no need to preset fixed deformation parameters. It can flexibly meet the processing needs of different types of medium and large disc parts, and the processing diameter has been increased from 200mm to 800mm. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of an embodiment of the present invention. Detailed Implementation

[0015] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] This embodiment targets a thin-walled, hollow aluminum alloy resolver support with a diameter of... mm (material 6061, wall thickness at the thinnest point is 8mm, weight 23kg), machined using a vertical lathe, the matching clamps weigh 50kg, and a 500mm long wrench needs to be manually used to adjust the movement of the clamp jaws.

[0017] The clamping system used in this embodiment includes: four clamping fixtures 3 for clamping the resolver bracket; four dial indicators 2, respectively set at each measuring point (including two fixed measuring points 1-1 and two initial adjustment measuring points 1-2), for monitoring the surface deformation of the resolver bracket; clamping force adjusting bolts 3-1 for adjusting the clamping force according to the reading of the dial indicators 2; the clamping fixtures 3 are clamping clamps for vertical lathes, the arc surface of the jaws matches the outer circle of the resolver bracket, and the clamping force is manually controlled by the clamping force adjusting bolts 3-1.

[0018] like Figure 1 As shown, four measuring points are evenly distributed along the outer circumference of the resolver bracket (the included angle between adjacent measuring points is 90°) and correspond to the center of the four clamping fixtures 3 respectively. Each measuring point is located on a flat and smooth part at the edge of the outer wall of the resolver bracket, with priority given to thin-walled areas with weaker rigidity, to ensure that the measuring points can accurately reflect the clamping deformation state of the parts.

[0019] Four dial gauges 2 are fixed to the base (non-moving part) of the clamping fixture 3 using a magnetic base or a fixed holder. The dial gauges 2 are adjusted so that their measuring heads are in perpendicular contact with the surface of the measuring point. The same preload of 0.2mm is set for each measuring head to ensure good contact. After the pointers of the dial gauges 2 stabilize, the indices of the four dial gauges 2 are returned to zero to complete the initialization.

[0020] Use a 500mm long wrench to pre-tighten the clamping fixture 3 corresponding to the two fixed measuring points 1-1 until its jaws are completely in contact with the outer surface of the resolver bracket; select a clamping deformation amount A1 that is one-third of the lower tolerance of the resolver bracket, and select only two decimal places, i.e., A1 = 0.07mm × 1 / 3 = 0.02mm; slowly rotate the clamping force adjusting bolt 3-1 corresponding to the initial adjustment measuring point 1-2 on the right, and observe the pointer of the corresponding dial indicator 2 until the index is stable at 0.02mm; repeat this operation to adjust the initial adjustment measuring point 1-2 below, ensuring that the index of its corresponding dial indicator 2 is also stable at 0.02mm.

[0021] Perform trial machining on the resolver bracket (cutting along the outer diameter, leaving a machining allowance of 0.5mm); after the trial machining is completed, measure the outer diameter of the part at four corresponding positions using an outside micrometer (accuracy 0.001mm) while it is clamped, and record the average value as B=759.95mm; remove the resolver bracket, and measure the outer diameter of the resolver bracket without clamping force using a coordinate measuring machine (accuracy 0.002mm), and record the average value as C=759.98mm; calculate the clamping deformation parameter D1=|BC|=|759.95-759.98|=0.03mm.

[0022] Re-clamp the resolver bracket, selecting a clamping deformation A2 that is two-thirds of the lower tolerance of the resolver bracket, and selecting only two decimal places, i.e., A2 = 0.07mm × 2 / 3 = 0.04mm; adjust the clamping force adjusting bolts 3-1 in sequence until the corresponding dial indicator 2 index is stable at 0.04mm; after trial machining, measure and calculate dimension B = 759.92mm, remove the resolver bracket, measure and calculate dimension C = 759.98mm, and calculate the deformation parameter D2 = |759.92-759.98| = 0.06mm; based on the two test data, calculate the clamping deformation coefficient E = (D2-D1) / (A2-A1) = (0.06-0.03) / (0.04-0.02) = 1.5.

[0023] According to the dimensional tolerance requirements of the resolver bracket ( (The minimum allowable size is 759.93mm). Calculate the maximum theoretical allowable reading of the dial indicator H = lower tolerance of part diameter / E = 0.07 / 1.5 ≈ 0.047mm. This value is the theoretical maximum safe value of the dial indicator reading. Since it is directly calculated from the lower tolerance of the part diameter, there is no margin. If the reading exceeds this value, the deformation of the part will definitely exceed the tolerance. Based on the machining allowance of 0.5mm reserved in the trial machining, determine the maximum allowable clamping deformation D0 during the formal machining of the part. D0 must be less than H. Select D0 = 0.04mm. Combined with the deformation coefficient E = 1.5, calculate the clamping deformation of the dial indicator during formal machining A = D0 / E = 0.04mm / 1.5 ≈ 0.027mm.

[0024] Re-clamp the resolver bracket and adjust the clamping force adjusting bolts 3-1 sequentially until the index of dial indicator 2 stabilizes at 0.027mm. Proceed with the formal machining. After machining, remove the resolver bracket. The coordinate measuring machine measures the outer diameter to be 759.95mm, which meets the requirements. The tolerance requirement is mm. Subsequently, by processing the same resolver bracket using this method, the dimensional tolerance requirements of the resolver bracket can be met.

[0025] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of the claims of the present invention, which are defined by the appended claims and their equivalents.

Claims

1. A method for controlling the clamping deformation of disc-shaped parts using a dial indicator, characterized in that, Includes the following steps: S1. Measuring points are set at several clamping positions on the outer wall of the wheel-type parts. Each measuring point is equipped with a dial indicator (2), and the dial indicator (2) is fixed on the base of the clamping fixture (3), and the measuring head of the dial indicator (2) is in perpendicular contact with the measuring point. S2. Set the same preload for each measuring head. After the pointers of the dial gauges (2) stabilize, reset the indexes of all dial gauges (2) to zero. S3. Calculate the actual deformation of the part corresponding to the unit percentage gauge deformation, i.e., the clamping deformation coefficient E: S3a. The measuring points include a number of fixed measuring points (1-1) and a number of initial adjustment measuring points (1-2), and the fixed measuring points (1-1) and the initial adjustment measuring points (1-2) are arranged opposite to each other in pairs; S3b. First, pre-tighten the clamping fixtures (3) corresponding to all fixed measuring points (1-1), and then pre-tighten the clamping fixtures (3) corresponding to the initial adjustment measuring points (1-2) in sequence, so that the dial indicator (2) corresponding to all initial adjustment measuring points (1-2) is stable at the clamping deformation amount A1; the clamping deformation amount A1 is less than the lower tolerance of the diameter of the wheel-type part; S3c. Perform trial machining on the wheel-type part along the outer circle direction and leave machining allowance. After the trial machining is completed, measure and calculate the average diameter of the part in the clamping state at all initial adjustment measurement points (1-2) as B; remove the part, measure and calculate the average diameter of the part in the non-clamping state as C, and calculate the deformation parameter D1=|BC|. S3d. Re-clamp the wheel-type parts and increase the clamping force so that the dial indicator (2) index corresponding to all initial adjustment measuring points (1-2) is stable at the clamping deformation amount A2. Repeat step S3c and calculate the deformation parameter D2; the clamping deformation amount A2 < the lower tolerance of the diameter of the wheel-type parts; S3e. Calculate the clamping deformation coefficient E=(D2-D1) / (A2-A1); S4. Based on the dimensional tolerance requirements of the wheel-type parts and the clamping deformation coefficient E, calculate the maximum theoretical allowable reading H of the dial indicator = lower tolerance of the part diameter / E; S5. Based on the reserved machining allowance, determine the maximum allowable clamping deformation D0 (D0 < H) during the formal machining of the part, and calculate the clamping deformation A = D0 / E during the formal machining; S6. Re-clamp the wheel-type parts and adjust the clamping force so that the dial indicator (2) corresponding to all initial adjustment measuring points (1-2) is stable at the clamping deformation amount A.

2. The method according to claim 1, characterized in that, The number of measuring points is 4, 6 or 8, and they are evenly distributed along the outer circumference of the wheel-like part.

3. The method according to claim 2, characterized in that, The measuring point is located in the thin-walled region where the rigidity of the disc-like part is relatively weak.

4. The method according to claim 1, characterized in that, The dial indicator (2) is mounted on the base of the clamping fixture (3) via a magnetic base or a fixed frame.

5. The method according to claim 1, characterized in that, The clamping deformation A1 is one-third of the lower tolerance of the part diameter, and the clamping deformation A2 is two-thirds of the lower tolerance of the part diameter.

6. The method according to claim 1, characterized in that, After trial processing, the diameter of the part is measured using an outside micrometer while it is clamped, and a coordinate measuring machine is used to measure the diameter of the part when it is not clamped.

7. The method according to claim 1, characterized in that, The disc-type parts are thin-walled disc-type parts with a diameter ≥300mm, a weight ≥10kg, and a hollow center.

8. The method according to claim 1, characterized in that, The clamping fixture (3) is a clamping clamp for a vertical lathe, and its clamping force is manually adjusted by the clamping force adjusting bolt (3-1).

Images