A detection tool for detecting flatness of a pipa surface

Abstract

This utility model discloses a flatness inspection fixture for a pipa-shaped surface, comprising a pipa-shaped surface positioning block, a rotating block, a rotating shaft positioning block, a dial indicator mounting plate, and a dial indicator. The pipa-shaped surface positioning block is positioned by a stop on the pipa-shaped surface and fixed by a positioning pin engaging with a threaded hole on the bridge housing. The rotating block and the dial indicator mounting plate are connected by a threaded structure. The rotating shaft positioning block passes through the pipa-shaped surface positioning block and the rotating block to ensure that the rotating block is located at the center of the bridge housing. The dial indicator is threadedly mounted on the dial indicator mounting plate for adjusting the height of the dial indicator and inspecting flatness. This utility model has a compact structure and is easy to operate. It does not rely on large precision equipment, and operators can quickly complete clamping and inspection on the processing site. The entire inspection process only requires manual rotation to read data, which is time-saving and greatly improves inspection efficiency, meeting the production line cycle requirements.

Description

Technical Field

[0001] This utility model relates to the field of mechanical inspection tools, and in particular to a tool for detecting the flatness of a pipa surface. Background Technology

[0002] In the manufacturing of automotive drive axle housings, the flatness of the flange surface (the large flange surface that mates with the main reducer) is a crucial precision indicator. If this flatness is out of tolerance or if a taper is present, it will cause the main reducer to not fit tightly against the axle housing, resulting in a "false torque" phenomenon when tightening bolts—that is, although the bolt torque reaches the specified value, the actual preload is insufficient due to poor planar contact. During vehicle operation, vibration and load changes can easily cause bolt connections to loosen or even detach, posing serious safety hazards. Furthermore, gaps in the mating surfaces can lead to lubricant leakage, affecting overall vehicle reliability and causing environmental pollution.

[0003] Currently, conventional methods for inspecting flatness mostly involve using a coordinate measuring machine (CMM) or manual measurement with a knife-edge ruler and feeler gauge. While CMMs offer high precision, they are expensive, require specific environmental conditions, and have long inspection cycles, making them unsuitable for rapid on-site inspections. The traditional method using a knife-edge ruler and feeler gauge relies entirely on the operator's experience and feel, resulting in highly subjective and unrepeatable measurements. Furthermore, it fails to provide precise quantitative values, allowing only approximate pass / fail assessments, which is insufficient to meet the demands of modern manufacturing for refined and digitalized quality data management.

[0004] Therefore, there is an urgent need in this field for a special inspection tool that can quickly, accurately, and intuitively read flatness values ​​and adapt to bridge housings of different specifications, so as to achieve efficient online inspection of the flatness of the bridge surface. Utility Model Content

[0005] The purpose of this invention is to address the shortcomings of existing technologies and provide a tool for testing the flatness of a pipa surface.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows: A pipa surface flatness testing fixture includes a pipa surface positioning block, a rotating block, a rotating shaft positioning block, a dial indicator mounting plate, and a dial indicator; The pipa surface positioning block is positioned by the stop on the pipa surface and is fixed by the positioning pin engaging with the threaded hole on the bridge housing. The rotating block is connected to the dial indicator mounting plate via a threaded structure. The rotating shaft positioning block runs through the pipa surface positioning block and the rotating block to ensure that the rotating block is located at the exact center of the bridge housing; The dial indicator is mounted on the dial indicator mounting plate by means of threads and is used to adjust the height of the dial indicator and to check the flatness.

[0007] Furthermore, the pipa-shaped positioning block is provided with multiple positioning pin holes to adapt to the threaded holes of different types of bridge housings.

[0008] Furthermore, the rotating block can be manually rotated, causing the dial indicator mounting plate and the dial indicator to rotate around the rotating axis positioning block, so as to realize the scanning detection of the flatness of the pipa surface.

[0009] Furthermore, the dial indicator mounting plate is provided with threaded holes for adjusting and fixing the height position of the dial indicator.

[0010] Furthermore, the rotating shaft positioning block has a stepped shaft structure, with the upper part cooperating with the rotating block and the lower part cooperating with the pipa-shaped positioning block, ensuring that the rotating shaft axis passes through the center of the bridge housing.

[0011] Furthermore, the gauge can be replaced with different sized locating blocks and dial indicator mounting plates to accommodate bridge housings of different specifications.

[0012] The beneficial effects of this utility model are as follows: 1. High detection efficiency, suitable for online detection: This utility model has a compact structure and is easy to operate, without relying on large precision equipment (such as a coordinate measuring machine). Operators can quickly complete clamping and detection on the processing site. The entire detection process only requires manual rotation to read data, which is time-saving and greatly improves detection efficiency, meeting the production line cycle requirements.

[0013] 2. Accurate and intuitive measurement results: Through a high-precision rotating structure and dial indicator, the entire surface of the pipa can be scanned and measured, and the flatness error is directly converted into the pointer reading on the dial indicator. The results are objective and quantitative, avoiding the subjective errors caused by the traditional knife-edge ruler and feeler gauge method. The measurement data has good repeatability and high reliability.

[0014] 3. High versatility and convenient switching: Through modular design, the gauge's locating block and dial indicator mounting plate can be quickly replaced to accommodate different bridge housing models with varying stop dimensions. Its threaded connection makes the switching process simple and reliable, achieving "one machine for multiple uses" and effectively reducing tooling manufacturing and management costs.

[0015] 4. High centering accuracy ensures measurement accuracy: The unique rotating shaft positioning block design runs through the entire system, ensuring that the rotation axis of the rotating block always coincides with the theoretical center of the bridge housing surface, eliminating measurement errors caused by eccentric rotation and fundamentally guaranteeing the accuracy of the measurement results.

[0016] 5. Fundamentally improve product quality and reliability: By achieving rapid and accurate flatness detection, it is possible to effectively prevent parts with excessive flatness from flowing into the next process or assembly line, thereby avoiding quality hazards such as bolt torque attenuation and oil leakage caused by flatness issues, and improving the safety and reliability of the drive axle assembly and the whole vehicle. Attached Figure Description

[0017] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of this utility model.

[0019] Figure 2 This is an assembly diagram of the present invention.

[0020] Figure 3 This is a cross-sectional schematic diagram of the rear axle housing of the vehicle in this embodiment. Detailed Implementation

[0021] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0022] Reference Figure 1 , Figure 2 A type of gauge for testing the flatness of a pipa surface mainly consists of a pipa surface positioning block 1, a rotating block 2, a rotating shaft positioning block 3, a dial indicator mounting plate 4, and a dial indicator 5.

[0023] The assembly process is as follows: The lower stepped shaft of the rotating shaft positioning block 3 is inserted into the center hole of the pipa-face positioning block 1 to form a first-level tight fit. Subsequently, the center hole of the rotating block 2 is fitted onto the upper stepped shaft of the rotating shaft positioning block 3 to form a second-level fit. This assembly process ensures that the rotating block 2 can rotate smoothly around a fixed axis coaxial with the center of the bridge housing.

[0024] Screw the dial indicator mounting plate 4 through the threaded hole at its bottom onto the pre-set threaded post at the upper end of the rotating block 2 and tighten it to secure it. Insert the measuring rod of the dial indicator 5 into the mounting hole at the top of the dial indicator mounting plate 4 and initially secure it with a set screw (not shown in the figure). The height position of the dial indicator 5 can be coarsely adjusted through the elongated hole on the dial indicator mounting plate 4 or the lifting mechanism; fine adjustment can be performed by finely adjusting the installation depth of the dial indicator itself to ensure that the dial indicator probe can contact the flange surface being measured and has a suitable preload.

[0025] Reference Figure 3Taking the inspection of the pipa-shaped surface of the rear axle housing of a Jiangling automobile (model: B01112Q0H-0995) as an example, the specific operating steps of this inspection tool are explained as follows: Select and install the positioning module: Based on the dimensions of the stop on the pipa-shaped face of the bridge housing (Ф274 (+0.35, +0.05)) and the positions of the three threaded holes, select the matching pipa-shaped face positioning block 1 (diameter Ф326mm) and the corresponding positioning pin.

[0026] Clamping and positioning: Align the locating block 1 of the fixture with the upper stop of the locating hole of the bridge housing, and gently insert it to achieve initial positioning by relying on the stop. Then, pass the three locating pins through the pin holes on the locating block and insert them into the threaded holes of the bridge housing to achieve precise positioning and circumferential fixation, ensuring that there is no relative movement between the fixture and the workpiece.

[0027] Zeroing and Measurement: Manually and gently rotate the rotating block 2 to make the dial indicator 5 rotate one revolution around the center of the bridge housing. Observe the swing range of the dial indicator 5 pointer; the difference between its maximum and minimum values ​​is the flatness error on that measurement circumference. To comprehensively evaluate the flatness of the entire flange surface, multiple measurements can be taken on circumferences of different radii (by adjusting the extension length of the dial indicator mounting plate 4), and the maximum value is taken as the final result.

[0028] Judgment and Recording: Compare the measured values ​​with the process requirements (such as 0.1mm) to determine whether the product is qualified, and record the measurement data.

[0029] In this embodiment, to adapt to the Jiangling axle housing, the dimensions of each key component of the inspection fixture are as follows: Pipa-shaped locating block 1: Diameter Ф326mm, width 70mm, thickness 25mm. It is equipped with three locating pins with diameter Ф8.7 (-0.02, -0.05)mm for mating with threaded holes on the bridge housing.

[0030] Rotating block 2: Diameter Ф150 (+0.01, -0.015) mm, height 70 mm, central through hole diameter φ50 (+0.1, +0.2) mm.

[0031] Rotary shaft positioning block 3: The upper stepped shaft has a diameter of φ50 (-0.1, -0.2) mm and mates with the rotating block 2; the lower stepped shaft mates with the center hole of the pipa-shaped positioning block 1. Total height: 75 mm.

[0032] Dial indicator mounting plate 4: 120mm long, 72mm wide, and 10mm thick. It has M5 threaded holes machined on it for mounting and fixing the dial indicator holder.

[0033] This invention features a compact structure and simple operation, eliminating the need for large precision equipment (such as coordinate measuring machines). Operators can quickly complete clamping and inspection on-site. The entire inspection process only requires manual rotation to read data, resulting in a short time consumption and significantly improving inspection efficiency to meet production line cycle requirements.

[0034] With its high-precision rotating structure and dial indicator, the entire surface of the pipa can be scanned and measured. The flatness error is directly converted into the pointer reading on the dial indicator. The results are objective and quantitative, avoiding the subjective errors caused by the traditional knife-edge ruler and feeler gauge method. The measurement data has good repeatability and high reliability.

[0035] Through modular design, the gauge's locating block and dial indicator mounting plate can be quickly replaced to accommodate different bridge housing models with varying stop dimensions. Its threaded connection makes the switching process simple and reliable, achieving "one machine for multiple uses" and effectively reducing tooling manufacturing and management costs.

[0036] The unique rotating shaft positioning block design runs through the entire system, ensuring that the rotation axis of the rotating block always coincides with the theoretical center of the bridge housing surface, eliminating measurement errors caused by eccentric rotation and fundamentally guaranteeing the accuracy of the measurement results.

[0037] By enabling rapid and accurate flatness detection, parts with excessive flatness can be effectively prevented from entering the next process or assembly line, thus avoiding potential quality problems such as bolt torque decay and oil leakage caused by flatness issues, and improving the safety and reliability of the drive axle assembly and the whole vehicle.

[0038] The above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model in any way. Any simple modifications, equivalent changes, and alterations made by those skilled in the art to the above embodiments based on the technical essence of the present utility model shall still fall within the scope of the present utility model's technical solution.

Claims

1. A gauge for testing the flatness of a pipa (a traditional Chinese stringed instrument), characterized in that: It includes a pipa-shaped positioning block (1), a rotating block (2), a rotating shaft positioning block (3), a dial indicator mounting plate (4), and a dial indicator (5); The pipa surface positioning block (1) is positioned by the stop on the pipa surface and is fixed by the positioning pin and the threaded hole on the bridge housing; The rotating block (2) is connected to the dial indicator mounting plate (4) by a threaded structure; The rotating shaft positioning block (3) passes through the pipa surface positioning block (1) and the rotating block (2) to ensure that the rotating block (2) is located at the center of the bridge shell; The dial indicator (5) is installed on the dial indicator mounting plate (4) by means of threads, and is used to adjust the height of the dial indicator and detect flatness.

2. The detection tool for the flatness of the surface of the piperace according to claim 1, wherein: The pipa-shaped positioning block (1) is provided with multiple positioning pin holes for adapting to the threaded holes of different types of bridge housings.

3. The detection tool for the flatness of the surface of the piperace according to claim 1, characterized in that: The rotating block (2) can be manually rotated to drive the dial indicator mounting plate (4) and the dial indicator (5) to rotate around the rotating axis positioning block (3) to achieve scanning detection of the flatness of the pipa surface.

4. The detection tool for the flatness of the surface of the piperace according to claim 1, wherein: The dial indicator mounting plate (4) is provided with threaded holes for adjusting and fixing the height position of the dial indicator (5).

5. The detection tool for the flatness of the surface of the piperace according to claim 1, characterized in that: The rotating shaft positioning block (3) is a stepped shaft structure. The upper part cooperates with the rotating block (2), and the lower part cooperates with the pipa surface positioning block (1) to ensure that the rotating shaft passes through the center of the bridge shell.

6. The detection tool according to any one of claims 1 to 5, wherein: The gauge can be replaced with different sized pipa-shaped positioning blocks (1) and dial indicator mounting plates (4) to adapt to different specifications of bridge housings.

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