Machining calibration and detection device for thin-walled deep blind hole symmetrical long chute

Abstract

This utility model relates to the field of machining technology, specifically to a machining calibration and inspection device for symmetrical long slide grooves in thin-walled deep blind holes. The device includes a positioning mandrel, which comprises a positioning shaft and multiple keyways disposed on the positioning shaft. The outer circumferential dimensions of the positioning shaft are adapted to the inner hole dimensions of the part to be machined. It also includes process keys and inspection keys, the dimensions of which are adapted to the dimensions of the keyways. This device can effectively ensure the machining accuracy of symmetrical long slide grooves in deep blind holes, improve the quality of key components, and effectively increase the production efficiency of parts.

Description

Technical Field

[0001] This utility model relates to the field of machining technology, specifically to a machining calibration and testing device for symmetrical long slides with thin-walled deep blind holes. Background Technology

[0002] like Figure 1 As shown, this part has a complex configuration of a thin-walled, deep blind hole. Its inner hole serves as the core functional datum and plays a decisive role in assembly positioning and mating. Therefore, the machining process of this part imposes extremely stringent geometric tolerance requirements on the symmetry accuracy between the long slide and the inner hole. This accuracy directly affects the functional matching effect and performance of the part.

[0003] In current actual manufacturing processes, the outer circle is commonly used as the positioning datum when milling long grooves, forming a datum conversion mode of "functional datum (inner hole) → positioning datum (outer circle)". However, this machining method has the following significant technical defects:

[0004] ① The cumulative effect of coaxiality errors is significant.

[0005] The prerequisite for the effective implementation of the aforementioned datum conversion mechanism is that the outer circle and the inner hole must maintain a strict coaxial relationship. However, in actual machining scenarios, this coaxiality requirement must overcome the influence of two types of error sources simultaneously: manufacturing process errors and fixture system errors. Specifically, machining processes of the inner hole and outer circle (such as turning and grinding) will generate static inherent form and position errors such as roundness, cylindricity, and coaxiality deviations; while the positioning fixture system will have dynamic introduced errors such as flatness and cylindricity errors of the positioning surface, as well as centering deviations from manual clamping or pneumatic fixtures. When these two types of errors are linearly superimposed, they will be transmitted to the long slideway machining stage through datum conversion. In other words, the strict symmetry requirement originally based on the "inner hole" becomes a symmetry control of "outer circle → long slideway" after datum conversion. This will significantly amplify the symmetry error between the long slideway and the inner hole, and the error transmission coefficient is positively correlated with the coaxiality deviation.

[0006] ② The mechanical deformation of thin-walled structures is severely affected.

[0007] Due to the thin-walled nature of this part, its structural rigidity is relatively low. During the milling process, the clamping force used to fix the workpiece can cause significant structural deformation. Specifically, the clamping force is concentrated on the outer cylindrical surface, causing localized elastic deformation and even plastic deformation of the outer cylindrical surface and the inner hole in the contact area. This results in the center lines of the two parts deviating from the ideal coaxial position. Moreover, this deformation has a clear "process-dependent" characteristic, and its degree changes dynamically with the magnitude and point of application of the clamping force, thus creating dynamic form and position errors and further compromising the symmetry accuracy between the long groove and the inner hole. More importantly, this irreversible plastic deformation leads to permanent misalignment between the inner hole and the outer cylindrical surface after machining. This not only significantly increases the technical difficulty of subsequent inspection (i.e., the inspection equipment needs to simultaneously fit the offset inner hole reference and the actual position of the groove), but also significantly reduces the reliability of the inspection data due to the instability of the reference, resulting in a significant increase in repeatability and reproducibility errors.

[0008] Therefore, how to solve the above problems has always been a problem that needs to be solved by those skilled in the art. Summary of the Invention

[0009] The purpose of this invention is to address the shortcomings of existing technologies by providing a machining calibration and testing device for symmetrical long slides in thin-walled deep blind holes. This device effectively ensures the machining accuracy of symmetrical long slides in deep blind holes, guaranteeing the quality of the key element, "symmetry between the long slide and the central axis of the inner hole," while simultaneously improving the production efficiency of the parts.

[0010] The objective of this utility model is achieved through the following solution:

[0011] A machining calibration and inspection device for symmetrical long slides in thin-walled deep blind holes includes a positioning mandrel, which includes a positioning shaft and a plurality of keyways disposed on the positioning shaft. The outer circumferential dimension of the positioning shaft is adapted to the inner hole dimension of the part to be machined. The device also includes a process key for machining calibration and positioning and a detection key for finished product inspection. The dimensions of the process key and the detection key are adapted to the dimensions of the keyways.

[0012] Preferably, the keyway includes a first plane and a second plane, wherein:

[0013] The first plane and the second plane are symmetrically arranged on both sides of the axial center line of the positioning mandrel, and the symmetry tolerance of the first plane and the second plane with respect to the axial center line is ≤0.025mm.

[0014] Preferably, the keyways are respectively disposed at both ends of the positioning shaft, and the number of keyways is 2.

[0015] Preferably, the detection key includes a positioning part and a detection part, wherein the outer peripheral dimension of the positioning part is adapted to the inner peripheral dimension of the keyway, and the outer peripheral dimension of the detection part is adapted to the groove width dimension of the machined part;

[0016] The symmetry tolerance of the outer circumferential centerline of the detection part relative to the outer circumferential centerline of the positioning part is ≤0.025mm.

[0017] Preferably, the distance between the first plane and the second plane is adapted to the width of the pre-grooved part to be processed, and the parallelism tolerance of the two planes is ≤0.025mm.

[0018] Preferably, the keyway further includes a stepped surface, which forms a height difference with the outer peripheral surface of the positioning shaft along the radial direction of the positioning shaft, and the height of the stepped surface is 3mm to 4mm lower than that of the outer peripheral surface of the positioning shaft.

[0019] Preferably, the parallelism tolerance of the two side walls of the process key is ≤0.025mm.

[0020] Preferably, it also includes a dial indicator for calibrating the parallelism between the positioning mandrel and the machine tool spindle.

[0021] The beneficial effects of this utility model are as follows:

[0022] 1. Traditional methods use the outer circle as a datum, requiring high coaxiality between the outer circle and the deep blind hole, and strict control over the manufacturing precision of the outer circle to ensure the machining accuracy of the part meets the requirements. This invention, however, changes the positioning datum from the outer circle to the inner hole, achieving datum positioning through the precise fit between the positioning mandrel and the inner hole. This solution eliminates the need for an outer circle datum, only requiring precise fit between the inner hole and the positioning mandrel, thereby reducing the machining accuracy requirements of the outer circle (e.g., relaxing the coaxiality tolerance of the outer circle), avoiding the deformation risk of high-precision machining of thin-walled parts, and simplifying the overall process route.

[0023] 2. Traditional external circle positioning requires the use of fixtures, which inevitably leads to manufacturing and installation errors in the fixtures. However, this utility model eliminates the influence of positioning fixture errors from the source by directly cooperating the positioning mandrel with the inner hole, avoiding the deformation of the outer circle of thin-walled parts caused by the clamping force of the fixture, and effectively achieving a fundamental improvement in positioning accuracy.

[0024] 3. This utility model uses a cooperation mechanism between the detection key and the positioning mandrel to achieve symmetry detection. The positioning mandrel has been used to position the part before processing. After processing, the detection key only needs to be inserted into the long slide. The physical fit of the detection key through the slide is observed to determine whether the part is qualified or not. This transforms the abstract symmetry detection into an intuitive judgment of whether it passes or not, effectively solving the measurement problem of traditional symmetry detection methods in deep blind holes.

[0025] 4. This utility model directly uses the inner hole as the reference for machining, eliminating the positioning error of the outer circle and eliminating the need for complex outer circle fixtures. While ensuring that the symmetry between the long slide and the inner hole is stable and meets the standards, it greatly reduces the clamping time and debugging process, and significantly improves production efficiency. Attached Figure Description

[0026] Figure 1 This is a drawing of the machined parts for this utility model;

[0027] Figure 2 This is a schematic diagram showing the use of a process key and a positioning mandrel in the machining of long slide grooves in this utility model;

[0028] Figure 3 This is a schematic diagram illustrating the use of a detection key and a positioning mandrel in the machining of long slide grooves in this utility model. Detailed Implementation

[0029] like Figures 1 to 3 As shown, a machining calibration and testing device for symmetrical long grooves in thin-walled deep blind holes includes a positioning mandrel 1. The positioning mandrel 1 includes a positioning shaft 101 and multiple keyways 102 disposed on the positioning shaft 101. The keyways are respectively disposed at both ends of the positioning shaft, and the number of keyways is two. Each keyway 102 includes a first plane 1021 and a second plane 1022, wherein the first plane 1021 and the second plane 1022 are symmetrically disposed on both sides of the axial centerline of the positioning mandrel 1, and the symmetry tolerance of the first plane 1021 and the second plane 1022 with respect to the axial centerline is ≤0.025mm. The distance between the first plane 1021 and the second plane 1022 is adapted to the width of the pre-grooved part to be machined, so that the process key 2 can be tightly embedded in the keyway 102, and the parallelism tolerance of the two planes is ≤0.025mm, which can ensure that the process key 2 is not tilted after being inserted into the keyway 102, and avoid the offset between the positioning mandrel 1 and the centerline of the inner hole of the part due to the plane skew.

[0030] The keyway 102 also includes a stepped surface 1023. The stepped surface 1023 forms a height difference with the outer peripheral surface of the positioning shaft 101 along the radial direction of the positioning shaft 101. The step height is 3mm to 4mm lower than the outer peripheral surface of the positioning shaft 101.

[0031] The outer circumferential dimensions of the positioning shaft 101 are adapted to the inner hole dimensions of the part to be machined, and the length of the positioning shaft 101 is the same as the inner hole depth of the part to be machined. In this embodiment, the outer circumferential dimensions of the positioning shaft 101 are... mm.

[0032] It also includes a process key 2 for machining calibration and positioning, and a detection key 3 for finished product inspection. The dimensions of both process key 2 and detection key 3 are adapted to the dimensions of the keyway 102. Specifically, the detection key 3 includes a positioning part 301 and a detection part 302. The outer circumferential dimension of the positioning part 301 is adapted to the inner circumferential dimension of the keyway 102, and the outer circumferential dimension of the detection part 302 is adapted to the groove width dimension of the machined part. The symmetry tolerance value of the center line of the outer circumferential dimension of the detection part 302 relative to the center line of the outer circumferential dimension of the positioning part 301 is ≤0.025mm. That is to say, in the actual production process, the symmetry between the center line of the outer circumferential dimension of the detection part 302 and the center line of the outer circumferential dimension of the positioning part 301 must meet strict precision standards, that is, the offset (i.e., the degree of asymmetry) between the center line of the detection part and the center line of the positioning part must not exceed 0.025mm. In layman's terms, the center lines of the two should be as close to the same plane as possible and symmetrical about the reference, and the deviation range should be controlled within 0.025mm. The parallelism tolerance of the two side walls of the process key 2 is ≤0.025mm, so as to ensure that the process key 2 and the two sides of the two keyways of the positioning mandrel 1 (i.e. the two positioning surfaces) form a precise fit, thereby achieving reliable positioning of the part during the processing and ensuring the symmetry requirements of the long slide and the deep blind hole.

[0033] It also includes a dial indicator for calibrating the parallelism between the positioning mandrel 1 and the machine tool spindle. A shoulder 103 is provided at one end of the positioning mandrel 1 to prevent the part from moving along the axial direction of the positioning mandrel 1, so as to ensure that the part maintains a stable axial position during the machining process, thereby ensuring the accuracy and reliability of the long slide groove machining.

[0034] The following is a specific embodiment of the above-mentioned device:

[0035] Example 1: Machining of a long slide groove for a part (positioning and calibration)

[0036] The structural parameters of the part to be machined are as follows: inner hole diameter is 50mm, wall thickness is 4mm, and hole depth is 586mm, which is a typical thin-walled deep blind hole structure. A long sliding groove needs to be machined on its hole wall, with specific dimensional requirements: groove width 16C11 (tolerance zone according to C11 standard), groove length 434mm; at the same time, the symmetry tolerance requirement between the long sliding groove and the inner hole is 0.1mm.

[0037] The specific steps are as follows:

[0038] S1: Install a dial indicator on the machine tool spindle for subsequent positioning accuracy measurement and calibration. Insert the positioning shaft 101, which matches the accuracy of the part's inner hole, into the pre-grooved inner hole of the part, so that the part is initially positioned and pre-pressed onto the machine tool. In this embodiment, the width of the pre-grooved slot is 12mm, and the tolerance zone is H9, that is, the width of the pre-grooved slot ranges from 12.000 to 12.043mm. At this time, insert a process key 2 into each of the two keyways 102. The thickness of the process key 2 is precisely matched with the width of the keyway 102 to ensure that there is no obvious gap after insertion.

[0039] S2: Move the machine tool worktable so that the dial indicator contacts the same side surface of the two process keys 2. By observing the reading of the dial indicator needle, fine-tune the position of the part so that the parallelism error between the surface and the machine tool spindle is controlled within the allowable range.

[0040] Continue moving the worktable, switching the dial indicator contact to the same surface on the other side of the process key, and repeat the fine-tuning operation until the runout accuracy of both surfaces meets the process requirements. By calibrating the symmetry of the two sides of the process key 2, it can be ensured that the axial centerline of the positioning mandrel coincides with the centerline of the machine tool spindle, thereby ensuring the symmetry of the long slide and the inner hole with the positioning mandrel 1 as the reference.

[0041] S3: After confirming that the dial indicator runout accuracy meets the requirements, perform final clamping on the part to ensure that the position remains unchanged during the machining process. Then, remove the two process keys 2 and start the machine tool to perform milling of the long slide groove.

[0042] Example 2: Inspection of long grooves in parts

[0043] S1: Insert the positioning mandrel 1 into the inner hole of the long slide groove part that has been machined, ensuring that the positioning mandrel 1 fits tightly with the inner hole, serving as the reference axis for inspection.

[0044] S2: Insert the positioning parts 301 of the two detection keys 3 into the keyway 102 at the same time. The thickness of the positioning part 301 matches the width of the keyway to ensure that the detection keys are accurately positioned on the spindle.

[0045] The detection section 302 of the detection key 3 is designed to match the groove width (16C11) of the long slide of the part, forming the following detection mechanism:

[0046] If the detection parts 302 of the two detection keys can pass smoothly through the long slide groove of the part at the same time, it means that the symmetry between the long slide groove and the positioning mandrel (i.e., the inner hole) meets the requirements (i.e., symmetry ≤ 0.1mm), and the part is judged to be qualified.

[0047] If the detection part 302 of any detection key cannot pass through the long slide, or if there is obvious jamming when passing through, it indicates that the symmetry is out of tolerance and the part is judged to be unqualified.

[0048] The device described in this embodiment reduces the overall machining difficulty of the part. While effectively controlling the quality of the key functional element of the product, "the symmetry between the long slide and the central axis of the inner hole," it also reduces the machining accuracy of the outer circle to a certain extent. Specifically, when using the outer circle as a positioning datum, the machining accuracy of the original outer circle needs to reach... With this device, the machining accuracy of the outer diameter can be increased to [specific value missing]. In other words, by using the device described in this embodiment, the number of machining operations on the outer diameter is reduced, and the machining and calibration efficiency of the parts is improved. Considering the time saved by the combined machining and inspection efficiency, production efficiency can be increased by 30%.

[0049] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications made to the present utility model by those skilled in the art without departing from the spirit of the present utility model shall fall within the protection scope of the present utility model.

Claims

1. A machining calibration and testing device for symmetrical long slide grooves with thin-walled deep blind holes, characterized in that, The system includes a positioning mandrel (1), which includes a positioning shaft (101) and a plurality of keyways (102) disposed on the positioning shaft (101). The outer circumferential dimensions of the positioning shaft (101) are adapted to the inner hole dimensions of the part to be processed. The system also includes a process key (2) for processing calibration positioning and a detection key (3) for finished product inspection. The dimensions of the process key (2) and the detection key (3) are adapted to the dimensions of the keyways (102).

2. The machining calibration and testing device for symmetrical long slides with thin-walled deep blind holes according to claim 1, characterized in that, The keyway (102) includes a first plane (1021) and a second plane (1022), wherein: The first plane (1021) and the second plane (1022) are symmetrically arranged on both sides of the axial center line of the positioning mandrel (1), and the symmetry tolerance of the first plane (1021) and the second plane (1022) with respect to the axial center line is ≤0.025mm.

3. The machining calibration and testing device for symmetrical long slides with thin-walled deep blind holes according to claim 1, characterized in that, The keyways (102) are respectively disposed at both ends of the positioning shaft (101), and the number of keyways (102) is 2.

4. The machining calibration and testing device for symmetrical long slides with thin-walled deep blind holes according to claim 1, characterized in that, The detection key (3) includes a positioning part (301) and a detection part (302). The outer circumferential dimension of the positioning part (301) is adapted to the inner circumferential dimension of the keyway (102), and the outer circumferential dimension of the detection part (302) is adapted to the groove width dimension of the processed part. The symmetry tolerance of the outer peripheral center line of the detection part (302) relative to the outer peripheral center line of the positioning part (301) is ≤0.025mm.

5. The machining calibration and testing device for symmetrical long slides with thin-walled deep blind holes according to claim 2, characterized in that, The distance between the first plane (1021) and the second plane (1022) is adapted to the width of the pre-grooved part to be processed, and the parallelism tolerance of the two planes is ≤0.025mm.

6. The machining calibration and testing device for symmetrical long slides with thin-walled deep blind holes according to claim 1, characterized in that, The keyway (102) also includes a stepped surface (1023), which forms a height difference with the outer peripheral surface of the positioning shaft (101) along the radial direction of the positioning shaft (101), and its step height is 3mm to 4mm lower than that of the outer peripheral surface of the positioning shaft (101).

7. The machining calibration and testing device for symmetrical long slides with thin-walled deep blind holes according to claim 1, characterized in that, The parallelism tolerance of the two side walls of the process key (2) is ≤0.025mm.

8. The machining calibration and testing device for symmetrical long slides with thin-walled deep blind holes according to claim 1, characterized in that, It also includes a dial indicator for calibrating the parallelism between the positioning mandrel (1) and the machine tool spindle.

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