Measurement method of the outer cylindrical surface tooth tip circle diameter of a grooved precision measuring tool

Abstract

The present invention discloses a precision measuring tool and a measuring method for the outer cylindrical surface tooth tip circle diameter with tooth grooves, which are mainly used for measuring the outer cylindrical surface diameters of rotary workpieces such as disc-shaped, columnar, and shaft-shaped workpieces with an odd number of tooth groove distributions in the production process of the aerospace machining field. By using the comparison method, a special or standard calibration block is used to calibrate and zero the general measuring instrument installed in the middle of the tool. During use, according to the change amount of the readings of the general measuring instrument that can be obtained, substituting it into the theoretical calculation formula, the indirect measurement of the outer diameter of the rotary workpiece with an odd number of tooth groove distributions is realized. The measuring tool of the present invention has high measuring accuracy, accurate and reliable measuring data, a large and adjustable measuring range, and has measuring functions that are not available in general calipers, bow micrometers, and special beam-type lever comparators.

Description

Technical Field

[0001] The present invention relates to the precise measurement of the outer cylindrical diameter of rotating workpieces such as disc-shaped, columnar, and shaft-shaped workpieces with tooth grooves during the production process in the field of aerospace machining. In particular, it relates to a measurement method for a precise measurement tool for the pitch circle diameter of the outer cylindrical surface with tooth grooves. Background Art

[0002] Rotating rotor components such as disc-shaped, columnar, and shaft-shaped components are widely used in the mechanical power systems of aeroengines and the transmission systems of aircraft. In the mechanical structures of the power and transmission systems of aeroengines, rotating components such as gas turbine discs, power turbine discs, spline drive shafts, and reduction gears generally have Figure 1 and Figure 2 the structures shown. Uniform gear grooves or serrated tenon grooves are designed on the outer cylindrical surfaces of the parts. Due to the strict dynamic balance requirements in the high-speed working environment of such parts, the dimensional and shape machining accuracies of their outer profiles are very high, posing higher requirements for inspection and measurement.

[0003] For the above-mentioned rotating parts with various gear grooves or serrated tenon grooves designed on the outer cylindrical surface, when the number of grooves is even, the positions of the grooves and the teeth are opposite to each other in the diameter direction of the part. At this time, a general caliper, bow micrometer, or special beam-type lever comparator can be used to precisely measure the pitch circle diameter. However, when the number of grooves is odd, the positions of the grooves and the teeth are opposite to each other in the diameter direction of the part. Since the opposite side of the convex tooth is a groove, the aforementioned general calipers, bow micrometers, and special beam-type lever comparators are no longer applicable. The diameter value of the pitch circle of the part with an odd number of grooves cannot be measured using the aforementioned general measuring tools. During the production process, when encountering the aforementioned parts with an odd number of tooth grooves, the common practice is to use a coordinate measuring machine to take points on the pitch circle of the convex teeth of the part, and then fit them into a circle, and the outer circle diameter of the part is calculated by a computer program. This method is applicable to fully machined finished parts. When the machining accuracy grade of the outer circle size of the part is relatively high, it is necessary to repeatedly grind the part with a small feed amount multiple times to meet the requirements. During this period, it is necessary to repeatedly measure the part on the machine tool to judge the remaining machining allowance in order to adjust the machining method. If the coordinate measuring machine is still used to measure the part size, the part needs to be unloaded from the machine tool, and then reinstalled on the machine tool after measurement. Repeating such clamping and alignment is extremely unfavorable to production efficiency and machining quality. The present invention is precisely generated based on the background of low measurement efficiency of the pitch circle of parts during the aforementioned production and machining process. Summary of the Invention

[0004] The object of the present invention is to provide a precision measuring tool and method for the outer diameter of the tooth top circle of the cylindrical surface with tooth grooves, which can effectively improve the efficiency of precision measurement of the outer diameter of the aforementioned workpiece, and has high measurement accuracy and reliability.

[0005] To solve the above technical problems, the precision measuring tool for the outer diameter of the tooth top circle of the cylindrical surface with tooth grooves provided by the present invention includes a V-shaped bracket. Adjusting holes are symmetrically provided on the supporting feet on both sides of the bracket. A measuring anvil with a threaded rod is installed in each of the adjusting holes. There is a locking nut on the outside of the supporting feet on both sides of the bracket. The threaded rod on the measuring anvil passes through the adjusting hole on the supporting foot and is locked on the supporting foot of the bracket by the locking nut after positioning.

[0006] An installation through hole is provided at the top of the bracket at the symmetric center of the V-shaped surface formed by the two measuring anvils. A dial gauge sleeve is installed at the upper part of the installation through hole. A locking dial gauge nut is installed on the dial gauge sleeve. A guide sleeve is installed at the lower part of the installation through hole. A measuring rod is installed inside the guide sleeve. The bottom measuring end of the measuring rod extends out of the bottom of the guide sleeve, and the top end is located inside the guide sleeve for butt joint and cooperation with the measuring head of the measuring instrument. A compression spring is installed on the measuring rod inside the guide sleeve so that the bottom measuring end of the measuring rod keeps close contact with the measured surface of the workpiece to be measured.

[0007] Furthermore, there is a rectangular guide groove on each of the V-shaped surfaces formed on the inner sides of the supporting feet on both sides of the bracket. A rectangular boss is provided on the outside of the measuring anvil. The rectangular boss on the measuring anvil is in clearance fit with the rectangular guide groove on the supporting foot of the bracket to prevent rotation.

[0008] Furthermore, the adjusting hole is set as a continuous hole groove, and the hole grooves intersect pairwise to form a rectangular adjusting hole with a continuous wavy convex serration;

[0009] The threaded rod on the measuring anvil is in small clearance fit with the arc surface of the wavy serrated rectangular groove to play a role in precise positioning.

[0010] Furthermore, the installation through hole is set as a threaded hole, and both the dial gauge sleeve and the guide sleeve are threadedly connected to the installation through hole.

[0011] Furthermore, a retaining shoulder is machined on the measuring rod, and a convex ring located above the measuring rod is provided on the inner wall of the guide sleeve or the dial gauge sleeve. The top end of the compression spring abuts against the convex ring, and the bottom end abuts against the retaining shoulder.

[0012] The measuring method of the above-mentioned precision measuring tool for the outer diameter of the tooth top circle of the cylindrical surface with tooth grooves includes the following steps:

[0013] A. Install a standard measuring instrument on the dial gauge sleeve and lock it with the dial gauge nut so that the measuring head of the measuring instrument abuts against and is butt-jointed with the top end of the measuring rod;

[0014] B. Assuming that the V-surface angle formed by the measuring anvil is θ, the theoretical outer diameter of the measured part is D0, and the actual outer diameter of the measured part is Di, the manufacturing error T is: T = |D0-Di| / 2;

[0015] C. Process a standard calibration block according to the theoretical outer diameter D0 of the measured part, and record the actual value D0' of the standard calibration block D0. Use the standard calibration block to calibrate the measuring instrument of the measuring tool to zero, and the manufacturing error T = |D0'-Di| / 2;

[0016] D. Use the calibrated and zeroed measuring tool to measure the actual outer diameter Di of the measured part: select two suitable symmetrical tooth top circle generatrixes on the measured part, and set the V surface of the measuring tool bracket on the selected part tooth top circle generatrix, so that the spherical contact of the measuring rod can fall on the cylindrical surface of the tooth top circle to be measured, clamp the measured part tightly with two measuring anvils, and read the offset Δ of the measuring rod through the standard measuring instrument installed on the meter clamp;

[0017] F. Measure the V-surface angle θ formed by the two measuring anvils, Δ=T / sin(θ / 2);

[0018] G. Calculate the actual outer diameter Di of the measured part: Di = D0' ± 2Δ·sin(θ / 2).

[0019] In summary, the technical effects of the present invention are:

[0020] 1. The comparison method is adopted to calibrate and return the universal measuring instrument installed in the middle of the tool to zero through a special or standard calibration block. When in use, the change in the reading of the universal measuring instrument that can be obtained is substituted into the theoretical calculation formula to realize the indirect measurement of the outer diameter of the rotating workpiece with an odd number of tooth grooves.

[0021] 2. The present invention has high measurement accuracy, accurate and reliable measurement data, a large and adjustable measurement range, and has measurement functions that general calipers, bow micrometers, and special beam-type lever comparators do not have.

[0022] 3. The traditional method of using a three-dimensional coordinate measuring machine to measure the size of a part requires the part to be unloaded from the machine tool and then re-clamped onto the machine tool after measurement. Such repeated clamping and alignment is extremely detrimental to production efficiency and processing quality. However, the present invention can measure the top circle of the part during the production and processing process without repeatedly disassembling and assembling the workpiece, which is beneficial to ensuring the processing quality and production efficiency of the parts during the processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the gear structure of the prior art.

[0024] Figure 2It is a schematic diagram of the turbine disk structure of the prior art.

[0025] Figure 3 It is a schematic diagram of the overall structure of the present invention.

[0026] Figure 4 It is a schematic diagram of the semi-sectional structure of the present invention.

[0027] Figure 5 It is a schematic diagram of the rectangular boss on the measuring anvil of the present invention.

[0028] Figure 6 It is a schematic diagram of the positional relationship between the measuring tool and the part to be measured during measurement of the present invention.

[0029] Figure 7 It is a schematic diagram of the working surface of the measuring anvil of the present invention.

[0030] In the figure, 1 is a bracket; 11 is an adjustment hole; 12 is an installation through-hole; 13 is a rectangular guide groove; 2 is a measuring anvil; 21 is a threaded tie rod; 22 is a rectangular boss; 3 is a locking nut; 4 is a dial holder; 41 is a convex ring; 5 is a dial nut; 6 is a guide sleeve; 7 is a measuring rod; 71 is a retaining shoulder; 8 is a compression spring. Specific embodiments

[0031] Now, the present invention will be described in detail with reference to the accompanying drawings. This figure is a simplified schematic diagram, which only illustrates the basic structure of the present invention in a schematic manner, so it only shows the components related to the present invention.

[0032] Refer to Figures 3 to 5 , a precision measuring tool for the outer cylindrical surface tooth tip circle diameter with tooth grooves disclosed in the present invention. The main structure of the measuring tool is a V-shaped bracket 1. On the supporting feet on both sides of the bracket 1, adjustment holes 11 are symmetrically provided. The adjustment holes 11 are continuous hole grooves, and the hole grooves intersect pairwise to form a rectangular groove with continuous wavy convex sawteeth. On each of the V-shaped surfaces formed by the inner sides of the two supporting feet, there is a rectangular guide groove 13. In each of the rectangular guide grooves 13, a T-shaped measuring anvil 2 with a threaded tie rod 21 and a rectangular boss 22 is installed. The rectangular boss 22 is arranged on the side of the measuring anvil 2 facing the supporting feet. The rectangular boss 22 on the measuring anvil 2 and the rectangular guide groove 13 on the supporting feet of the bracket 1 are in clearance fit to prevent rotation.

[0033] The threaded pull rod 21 on the measuring anvil 2 has a small clearance fit with the arc surface of the adjusting hole 11, which plays an accurate positioning role. By adjusting the installation position of the measuring tool 2 in the adjusting hole 11, the measuring range of the measuring tool can be adjusted, and the measurement of different outer circle diameters in a large range can be realized. There is a locking nut 3 on the outer side of each of the two side feet of the bracket 1, and the locking nut 3 is set as a knurled high-foot nut. After the threaded pull rod 21 on the measuring anvil 2 passes through the adjusting hole 11 on the foot for positioning, it is firmly locked on the foot of the bracket 1 by the locking nut 3.

[0034] At the symmetric center of the V-shaped surface formed by the two measuring anvils on the top of the bracket 1, there is an installation through hole 12. A clamp sleeve 4 is installed on the upper part of the installation through hole 12, and a clamping clamp nut 5 is installed on the clamp sleeve 4. An outwardly protruding guide sleeve 6 is installed on the lower part of the installation through hole 12. A slender measuring rod 7 with a spherical contact head is installed inside the guide sleeve 6. The bottom measuring end of the measuring rod 7 extends out of the bottom of the guide sleeve 6, and the top end is located inside the guide sleeve 6 for butt joint and cooperation with the measuring head of the measuring instrument. A compression spring 8 is installed between the inside of the clamp sleeve 4 and the measuring rod 7. When using this measuring tool to measure the outer diameter of the workpiece, the compression spring 8 can keep the spherical contact head at the bottom of the measuring rod 7 in close contact with the measured surface of the workpiece to be measured. After the contact pressure is removed, the compression spring 8 can reset the measuring rod 7.

[0035] Specifically, the installation through hole 12 is set as a threaded hole, and both the clamp sleeve 4 and the guide sleeve 6 are threadedly connected to the installation through hole 12.

[0036] Specifically, a retaining shoulder 71 is machined on the measuring rod 7, and a convex ring 41 located above the measuring rod 7 is provided on the inner wall of the guide sleeve 6 or the clamp sleeve 4. The top end of the compression spring 8 abuts against the convex ring, and the bottom end abuts against the retaining shoulder 71. In this embodiment, the convex ring 41 is provided on the inner wall of the clamp sleeve 4, and it can also be provided on the inner wall of the guide sleeve 6 in other embodiments. When not measuring, the measuring rod 7 installed in the guide sleeve 6 can make its retaining shoulder 71 stuck at the end face of the shaft hole of the guide sleeve 6 under the elastic action of the compression spring 8, so as not to slip out; when using this measuring tool to measure the outer diameter of the workpiece, the compression spring 8 can keep the spherical contact head at the bottom of the measuring rod 7 in close contact with the measured surface of the workpiece to be measured. Under the action of external force, the measuring rod 7 can push the measuring head rod of the dial indicator or micrometer to move, so that the reading can be obtained on the dial indicator or micrometer. After the contact pressure is removed, the compression spring 8 can reset the measuring rod 7.

[0037] The measuring method of the measuring tool described in the present invention is as follows:

[0038] As attached Figure 6As shown in the figure, select two appropriate symmetric tooth top circle generatrices on the part to be measured. The V-plane of the measuring tool is placed on the selected tooth top circle generatrix of the part, so that the spherical contact of the measuring rod 7 on the upper part of the measuring tool can fall on the cylindrical surface of the tooth top circle to be measured. Assume that the included angle of the V-plane formed by the measuring anvil 2 is θ (note: attached Figure 7 As shown in the schematic structural diagram of the measuring anvil 2, the working surface angle of the measuring anvil is α≥0°. By adjusting α, the included angle θ of the V-plane formed by the measuring anvil 2 can be changed, so that the measuring tool meets different usage conditions). The theoretical outer circle diameter of the part to be measured is D0, and the actual outer circle diameter of the part to be measured is Di. Then the manufacturing error T is:

[0039] T = |D0 - Di| / 2 (Formula 1)

[0040] When using the measuring tool of the present invention, first, a standard calibration block needs to be machined according to the theoretical outer circle diameter D0 of the part to be measured, and the actual value D0' of the standard calibration block D0 is recorded. The measuring tool is calibrated to zero with the standard calibration block. Then, the actual outer circle diameter Di of the part to be measured is measured with the calibrated and zeroed measuring tool. Then the manufacturing error is:

[0041] T = |D0' - Di| / 2 (Formula 2)

[0042] Due to the existence of the part manufacturing error T, the theoretical position (attached Figure 6 thick solid line) of the measuring tool will have an inward or outward offset Δ (attached Figure 6 thick dashed line), that is, the offset amount Δ of the measuring rod 7 on the measuring tool is:

[0043] A = T / sin(θ / 2) (Formula 3)

[0044] The offset amount Δ can be directly read and obtained by a standard measuring instrument such as a dial indicator or a micrometer installed on the gauge clamp 4. Thus, the manufacturing error T of the part to be measured is:

[0045] T = A·sin(θ / 2) (Formula 4)

[0046] From Formula (2) and Formula (4), the actual outer circle diameter Di of the part to be measured can be obtained as:

[0047] Di = D0' ± 2A·sin(θ / 2) (Formula 5)

[0048] Among them: take "-" when pressing the gauge, and take "+" when pulling the gauge.

[0049] The embodiments of this specific implementation manner are all preferred embodiments of the present invention, and do not limit the protection scope of the present invention accordingly. Therefore, all equivalent changes made according to the structure, shape, and principle of the present invention should be covered within the protection scope of the present invention.

Claims

1. Measuring method of a precision measuring tool for the outer cylindrical surface tooth tip circle diameter with tooth grooves, Characterized in that: The measuring tool includes a V-shaped bracket. Adjusting holes are symmetrically arranged on the supporting feet on both sides of the bracket. A measuring anvil with a threaded rod is installed in each of the adjusting holes. There is a locking nut on the outside of the supporting feet on both sides of the bracket. The threaded rod on the measuring anvil passes through the adjusting hole on the supporting foot and is locked on the supporting foot of the bracket by the locking nut after positioning; An installation through hole is opened at the top of the bracket at the symmetric center of the V-shaped surface formed by the two measuring anvils. A dial clamp sleeve is installed at the upper part of the installation through hole. A locking dial clamp nut is installed on the dial clamp sleeve. A guide sleeve is installed at the lower part of the installation through hole. A measuring rod is installed inside the guide sleeve. The bottom measuring end of the measuring rod extends out of the bottom of the guide sleeve, and the top end is located inside the guide sleeve for butt joint and cooperation with the measuring head of the measuring instrument. A compression spring is installed on the measuring rod inside the guide sleeve to keep the bottom measuring end of the measuring rod in close contact with the measured surface of the workpiece to be measured; The measuring method of the precision measuring tool for the outer cylindrical surface tooth tip circle diameter with tooth grooves includes the following steps: A. Install a standard measuring instrument on the dial clamp sleeve and lock it with the dial clamp nut so that the measuring head of the measuring instrument abuts and docks with the top end of the measuring rod; B. Assume that the included angle of the V surface formed by the measuring anvils is θ, the theoretical outer circle diameter of the part to be measured is D0, and the actual outer circle diameter of the part to be measured is Di. Then the manufacturing error T is: T = |D0 - Di| / 2; C. Machine a standard calibration block according to the theoretical outer circle diameter D0 of the part to be measured, and record the actual value D0' of the standard calibration block D0. Use the standard calibration block to calibrate and zero the measuring instrument of the measuring tool. The manufacturing error T = |D0' - Di| / 2; D. Use the calibrated and zeroed measuring tool to measure the actual outer circle diameter Di of the part to be measured: Select two appropriate symmetric tooth tip circle generatrices on the part to be measured. The V surface of the measuring tool bracket is placed on the selected part tooth tip circle generatrix so that the spherical contact head of the measuring rod can fall on the cylindrical surface of the tooth tip circle to be measured. The two measuring anvils clamp and press against the part to be measured, and read the offset Δ of the measuring rod through the standard measuring instrument installed on the dial clamp sleeve; F. Measure the included angle θ of the V surface formed by the two measuring anvils, Δ = T / sin(θ / 2); G. Calculate the actual outer circle diameter Di of the part to be measured: Di = D0' ± 2Δ · sin(θ / 2).

2. The measuring method of the precision measuring tool for the outer cylindrical surface tooth tip circle diameter with tooth grooves according to claim 1, Characterized in that: There is a rectangular guide groove on each of the V-shaped surfaces formed by the inner sides of the supporting feet on both sides of the bracket. A rectangular boss is arranged on the outside of the measuring anvil. The rectangular boss on the measuring anvil is in clearance fit with the rectangular guide groove on the supporting foot of the bracket to play a role in preventing rotation.

3. The measuring method of the precision measuring tool for the outer cylindrical surface tooth tip circle diameter with tooth grooves according to claim 1, Characterized in that: The adjusting hole is set as a continuous hole groove. The hole grooves intersect pairwise to form a rectangular adjusting hole with a continuous wavy convex sawtooth. The threaded tie rod on the measuring anvil is in small clearance fit with the arc surface of the wavy serrated rectangular groove, playing a role in precise positioning.

4. The measuring method of the precision measuring tool for the outer cylindrical surface tooth tip circle diameter with tooth grooves according to claim 1, characterized in that: The installation through hole is set as a threaded hole, and both the dial holder and the guide sleeve are threadedly connected to the installation through hole.

5. The measuring method of the precision measuring tool for the outer cylindrical surface tooth tip circle diameter with tooth grooves according to claim 1, characterized in that: A retaining shoulder is machined on the measuring rod, and a convex ring located above the measuring rod is provided on the inner wall of the guide sleeve or the dial holder. The top end of the compression spring abuts against the convex ring, and the bottom end abuts against the retaining shoulder.

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