Measuring tool for measuring inner clamping groove of annular piece and measuring method thereof

Abstract

The invention relates to the technical field of machining measurement, in particular to a measuring tool for measuring an inner clamping groove of an annular piece and a measuring method thereof, the measuring tool comprises a measuring reference seat and a movable measuring mechanism, the measuring reference seat comprises two opposite reference surfaces, and the distance between the two reference surfaces is a reference distance; the movable measuring mechanism comprises a telescopic adjusting rod, a measuring main body, a dial indicator and an extension rod. During measurement, the two ends of the movable measurement mechanism abut against the reference surface of the measurement reference seat in a reference state, the dial indicator is zeroed, and calibration is completed. And then in a measurement state, two ends of the calibrated movable measurement mechanism are directly abutted against two sides of the clamping groove of the workpiece, the reading of the dial indicator is the deviation between the actual size of the clamping groove and the reference distance, and the accurate size is obtained through calculation. According to the invention, a unified traceability reference is provided through the measurement reference seat, manual and clamping errors are eliminated, the measurement consistency and accuracy are ensured, the operation is simplified by the integrated movable measurement mechanism, and the measurement efficiency and the standardization level are greatly improved.

Description

Technical Field

[0001] This invention relates to the field of machining measurement technology, and in particular to a measuring fixture and method for measuring the inner groove of an annular part. Background Technology

[0002] In the machinery manufacturing industry, the dimensional accuracy of the grooves inside ring-shaped workpieces (such as bearing rings, gear rings, flange rings, etc.) directly affects the assembly performance and service life of the workpiece, making the measurement process crucial. Currently, the traditional methods for measuring the dimensions of grooves inside such ring-shaped parts are to use calipers or plug gauges for go / no-go checks, or to use micrometers or dial indicators for direct measurement.

[0003] While using clamps or plug gauges for go / no-go testing is simple in structure, it can only make qualitative judgments and cannot obtain specific dimensional values, thus failing to provide effective data support for process adjustments. Moreover, the lack of a stable and reliable positioning reference during measurement makes the measurement results susceptible to the workpiece's placement posture and the operator's subjective factors, resulting in poor measurement repeatability. Furthermore, it cannot adapt to slight deformations that may occur after workpiece processing, which can easily lead to measurement misjudgments.

[0004] While direct measurement using a micrometer or inside micrometer can yield specific measurement values, it has serious shortcomings when measuring the grooves inside annular parts: First, the measuring head of a general-purpose measuring tool is difficult to position stably within the narrow annular groove, and deviation is prone to occur during measurement, introducing large measurement errors; second, the operation process is complex, requiring operators to have a high level of skill, and each measurement requires repeated adjustments and alignment, resulting in low measurement efficiency; finally, due to the lack of a dedicated positioning benchmark, the results obtained by different operators or at different measurement positions are inconsistent, making it difficult to achieve standardized measurement.

[0005] Therefore, existing measuring tools for the internal grooves of annular workpieces generally suffer from problems such as unstable measurement accuracy, low operating efficiency, high dependence on personnel skills, and inconsistencies between measurement results and coordinate measuring machine (CMM) data. There is an urgent need to develop a special measuring fixture designed specifically for the structural characteristics of the internal grooves of annular workpieces. This fixture should possess a stable mechanical positioning reference, a simple operating procedure, and reliable numerical measurement capabilities. This would solve the problem of the mismatch between the structure, reference, and operating procedure of existing general-purpose measuring tools and the measurement requirements of internal grooves of annular workpieces, and achieve efficient, accurate, and stable batch testing. Summary of the Invention

[0006] This invention provides a measuring fixture and method for measuring the inner groove of an annular part, which solves the defects of existing measuring tools for the inner groove of annular workpieces, such as unstable measurement accuracy, low operating efficiency, high dependence on personnel skills, and inconsistency between measurement results and coordinate measuring machine data.

[0007] This invention provides a measuring fixture for measuring the groove inside a ring-shaped part, comprising a measuring reference base and a movable measuring mechanism. The measuring reference base includes two opposing reference surfaces, the distance between which is a reference distance. The movable measuring mechanism includes a telescopic adjusting rod, a measuring body, a dial indicator, and an extension rod. The first end of the telescopic adjusting rod is fixedly connected to the first end of the measuring body. The dial indicator is fixed to the measuring body, and the measuring head of the dial indicator is movably inserted through the second end of the measuring body. The first end of the extension rod is connected to the measuring head of the dial indicator.

[0008] The active measuring mechanism includes a reference state and a measuring state. In the reference state, the second end of the telescopic adjustment rod and the second end of the extension rod respectively abut against the two reference surfaces of the measuring reference base. In the measuring state, the second end of the telescopic adjustment rod and the second end of the extension rod respectively abut against the inner groove of the annular part to be measured.

[0009] According to the present invention, a measuring fixture for measuring the inner groove of an annular component is provided. The telescopic adjusting rod includes a hollow rod, a solid rod, and a locking buckle. The first end of the hollow rod is fixedly connected to the first end of the measuring body. The side wall of the second end of the hollow rod has an adjusting slot arranged along the axial direction of the hollow rod. The solid rod is movably inserted through the second end of the hollow rod. The locking buckle is sleeved on the outer circumferential surface of the second end of the hollow rod and is used to adjust the inner diameter of the hollow rod to lock the hollow rod and the solid rod.

[0010] According to the present invention, a measuring fixture for measuring the inner groove of an annular part is provided, wherein a guide groove is formed on the side wall of the hollow rod and is arranged along the axial direction of the hollow rod, and a first guide pin is provided on the outer peripheral surface of the end of the solid rod, and the first guide pin is movably disposed in the guide groove.

[0011] According to the present invention, a measuring fixture for measuring the groove inside a ring-shaped part is provided. The measuring body is a frame-shaped part. The first end of the frame-shaped part is connected to the telescopic adjustment rod. The second end of the frame-shaped part is provided with a sleeve assembly. The dial indicator is located inside the frame-shaped part, and the sleeve around the measuring head of the dial indicator is connected to the sleeve assembly. The measuring head of the dial indicator is located inside the sleeve assembly. The extension rod is movably inserted through the sleeve assembly and is fixedly connected to the measuring head of the dial indicator inside the sleeve assembly.

[0012] According to the present invention, a measuring fixture for measuring the inner groove of an annular component includes a sleeve assembly comprising a connecting sleeve, a limiting nut, and a locking nut. The connecting sleeve passes through the second end of the measuring body, and a limiting step is formed on the outer circumferential surface of the connecting sleeve. The limiting nut is sleeved on the outer circumferential surface of the connecting sleeve, and the limiting nut and the limiting step of the connecting sleeve are respectively located on the inner and outer sides of the second end of the measuring body for clamping the measuring body. The locking nut is sleeved on the end of the connecting sleeve facing the dial indicator for locking and fixing the sleeve on the outer circumference of the measuring head of the dial indicator to the end of the connecting sleeve.

[0013] According to the present invention, a measuring fixture for measuring the inner groove of an annular part is provided, wherein a spring is sleeved on the outer periphery of the measuring head of the dial indicator, the first end of the spring abuts against the sleeve on the outer periphery of the measuring head of the dial indicator, and the second end of the spring abuts against the extension rod.

[0014] The extension rod has an elongated hole arranged along the axial direction of the extension rod, and the connecting sleeve is provided with a second guide pin, which is movably disposed in the elongated hole of the extension rod.

[0015] According to the present invention, a measuring fixture for measuring the inner groove of an annular part is provided. The measuring reference base includes a base, two positioning blocks and a handle. The two positioning blocks are fixed on the base and are arranged opposite to each other. The opposite surfaces of the two positioning blocks form two reference surfaces. The handle is fixedly connected to the base.

[0016] According to the present invention, a measuring fixture for measuring the inner groove of an annular part is provided, wherein the second end of the telescopic adjustment rod and the second end of the extension rod are formed with a vertical bending portion, the vertical bending portion being used to adapt to the measuring space of the inner groove of the annular part to be measured.

[0017] According to the present invention, a measuring fixture for measuring the inner groove of an annular part is provided, wherein the second end of the telescopic adjustment rod, the second end of the extension rod, and the two opposing reference surfaces of the measuring reference base are all subjected to quenching or surface nitriding treatment, and the flatness of the two opposing reference surfaces of the measuring reference base is less than 0.05 mm.

[0018] The present invention also provides a method for measuring the inner groove of an annular part, applicable to the measuring fixture for measuring the inner groove of an annular part as described in any of the above-mentioned methods, comprising the following steps S1 to S4.

[0019] S1. Place the measuring reference base on the platform.

[0020] S2. By adjusting the telescopic adjustment rod, the second end of the telescopic adjustment rod and the second end of the extension rod are respectively abutted against the two reference surfaces of the measuring reference base, so that the movable measuring mechanism is in the reference state at the reference distance, and the dial indicator is zeroed.

[0021] S3. The measuring mechanism in the reference state measures the groove inside the annular part to be measured. The second end of the telescopic adjustment rod and the second end of the extension rod are respectively abutted against the groove inside the annular part to be measured, and the display value of the dial indicator is read.

[0022] S4. Calculate the actual size of the groove inside the annular part to be measured based on the reference distance and the reading of the dial gauge.

[0023] This invention provides a measuring fixture for measuring the inner groove of a ring-shaped part. By setting a measuring reference base with a fixed reference distance, the movable measuring mechanism is divided into two working modes: a reference state and a measuring state. In the reference state, by adjusting the telescopic adjustment rod, the telescopic adjustment rod and the extension rod are respectively abutted against the two reference surfaces of the measuring reference base. At this position, the dial indicator is zeroed, thereby accurately recording the known reference distance into the movable measuring mechanism. In the measuring state, no further adjustment is needed. The calibrated movable measuring mechanism can be used directly, with the ends of the telescopic adjustment rod and the extension rod respectively abutting against both sides of the inner groove of the ring-shaped part to be measured. The change in the dial indicator reading represents the deviation of the actual size of the groove from the reference distance. The accurate size can be obtained through simple calculation. The measuring reference base of this invention provides a unified and traceable reference distance, eliminating errors caused by workpiece positioning posture and operator subjectivity, ensuring the consistency of measurement data with coordinate measuring machine (CMM) detection results. Meanwhile, the integrated design of the moving measuring mechanism simplifies the measurement action to three steps: zeroing, contact, and reading. Operators do not need to repeatedly adjust and calibrate, which significantly improves measurement efficiency and standardization. It effectively overcomes the technical defects of traditional caliper measurement methods, such as low accuracy and cumbersome operation of general measuring tools. It is especially suitable for rapid, accurate, and reliable on-site inspection of the grooves inside ring parts in mass production. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the overall structure of the measuring fixture for measuring the inner groove of a ring-shaped part provided by the present invention.

[0026] Figure 2This is an exploded view of the telescopic adjustment rod provided by the present invention.

[0027] Figure 3 This is a schematic diagram of the connection structure of the dial indicator, sleeve assembly, and extension rod provided by the present invention.

[0028] Figure 4 yes Figure 3 Exploded view.

[0029] Reference numerals in the attached drawings: 1. Measuring reference base; 11. Base; 12. Positioning block; 13. Handle; 2. Telescopic adjustment rod; 21. Hollow rod; 211. Adjustment slot; 212. Guide groove; 22. Solid rod; 221. First guide pin; 23. Locking buckle; 3. Measuring body; 4. Dial indicator; 5. Extension rod; 6. Sleeve assembly; 61. Connecting sleeve; 62. Limit nut; 63. Locking nut; 7. Spring; 8. Second guide pin. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0031] In the description of the embodiments of the present invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0032] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention based on the specific circumstances.

[0033] In embodiments of the present invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0034] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0035] The following is combined Figures 1 to 4 This invention describes the measuring fixture and method for measuring the inner groove of an annular component.

[0036] One embodiment of the present invention provides a measuring fixture for measuring the inner groove of an annular component, see [link to relevant documentation]. Figure 1 As shown, the measuring fixture for measuring the groove inside the annular part includes a measuring reference base 1 and a movable measuring mechanism. The measuring reference base 1 includes two opposing reference surfaces, with a known reference distance between the two reference surfaces. The movable measuring mechanism includes a telescopic adjustment rod 2, a measuring body 3, a dial indicator 4, and an extension rod 5. The first end of the telescopic adjustment rod 2 is fixedly connected to the first end of the measuring body 3. The dial indicator 4 is fixed to the measuring body 3, and the measuring head of the dial indicator 4 is movably inserted through the second end of the measuring body 3. The first end of the extension rod 5 is connected to the measuring head of the dial indicator 4.

[0037] The active measuring mechanism includes a reference state and a measuring state. In the reference state, the second end of the telescopic adjustment rod 2 and the second end of the extension rod 5 respectively abut against the two reference surfaces of the measuring reference base 1. In the measuring state, the second end of the telescopic adjustment rod 2 and the second end of the extension rod 5 respectively abut against the inner groove of the annular part to be measured.

[0038] It is understood that this measuring fixture for measuring the groove inside a ring-shaped part, in this embodiment, uses a measuring reference base 1 with a fixed reference distance to divide the movable measuring mechanism into two working modes: a reference state and a measuring state. In the reference state, by adjusting the telescopic adjustment rod 2, the telescopic adjustment rod 2 and the extension rod 5 are respectively abutted against the two reference surfaces of the measuring reference base 1, and the dial indicator is zeroed at this position, thereby accurately recording the known reference distance into the movable measuring mechanism. In the measuring state, no further adjustment is needed. The calibrated movable measuring mechanism can be used directly, with the ends of the telescopic adjustment rod 2 and the extension rod 5 respectively abutting against both sides of the groove inside the ring-shaped part to be measured. The change in the dial indicator 4 represents the deviation of the actual size of the groove from the reference distance, and the accurate size can be obtained through simple calculation.

[0039] The separate design of the movable measuring mechanism and the measuring reference base 1 enables rapid and stable positioning of the measuring device: the measuring reference base 1 provides an external calibration platform, while the compact movable measuring mechanism can easily extend into the annular workpiece. Its extension rod 5 at one end can push the measuring head of the dial indicator 4 to retract, and in conjunction with the telescopic adjustment rod 2 at the other end, it stably abuts against both sides of the slot, eliminating the need for tedious fine-tuning and alignment within the slot. The measuring reference base 1 establishes a traceable and precise length reference, and the dial indicator 4 enables numerical and readable dimensional deviation measurement, eliminating the ambiguity of qualitative measurements and dependence on operator feel. In this embodiment, the measuring reference base 1 provides a uniform and traceable reference distance, eliminating errors caused by workpiece positioning posture and operator subjectivity, ensuring consistency between measurement data and coordinate measuring machine (CMM) detection results. Meanwhile, the integrated design of the moving measuring mechanism simplifies the measurement action to three steps: zeroing, contact, and reading. Operators do not need to repeatedly adjust and calibrate, which significantly improves measurement efficiency and standardization. It effectively overcomes the technical defects of traditional caliper measurement methods, such as low accuracy and cumbersome operation of general measuring tools. It is especially suitable for rapid, accurate, and reliable on-site inspection of the grooves inside ring parts in mass production.

[0040] In some embodiments of the measuring fixture of the present invention for measuring the groove inside a ring-shaped part, see [link to relevant documentation]. Figure 2 As shown, the telescopic adjustment rod 2 includes a hollow rod 21, a solid rod 22, and a locking buckle 23. The first end of the hollow rod 21 is fixedly connected to the first end of the measuring body 3. The side wall of the second end of the hollow rod 21 forms an adjustment slot 211 arranged along the axial direction of the hollow rod 21. The solid rod 22 is movably inserted through the second end of the hollow rod 21. The locking buckle 23 is sleeved on the outer circumferential surface of the second end of the hollow rod 21 and is used to adjust the inner diameter of the hollow rod 21 to lock the hollow rod 21 and the solid rod 22.

[0041] It is understood that the structure of the telescopic adjustment rod 2 is a key component for the precise adjustment and reference locking of the active measuring mechanism of the present invention. In the measuring fixture structure of this embodiment, the telescopic adjustment rod 2 is composed of a hollow rod 21, a solid rod 22, and a locking buckle 23. One end of the hollow rod 21 is fixed to the measuring body 3, and the other end has an adjustment slot 211 opened along the axial direction. The adjustment slot 211 extends axially from the end and penetrates the side wall of the hollow rod 21. Two adjustment slots 211 can be symmetrically arranged around the circumference of the hollow rod 21. The solid rod 22 is slidably inserted into the hollow rod 21. The stepless adjustment of the overall length of the telescopic adjustment rod 2 is achieved by the relative displacement change of the hollow rod 21 and the solid rod 22. The locking buckle 23 precisely controls the opening and closing of the adjustment slot 211 by clamping the end of the hollow rod 21, thereby achieving stable locking of the solid rod 22.

[0042] When the reference measurement span needs to be adjusted, the operator only needs to loosen the locking buckle 23 to easily slide the solid rod 22 to the required length, and then tighten the locking buckle 23 to close the adjustment slot 211, which will firmly lock the hollow rod 21 and the solid rod 22. This not only achieves fast and accurate length adjustment, but also provides uniform and reliable clamping force without damaging the surface of the rod through the synergistic effect of the adjustment slot 211 and the locking buckle 23, avoiding the thread wear or gap problems that may occur in traditional thread adjustment methods.

[0043] It is important to understand that the stepless adjustment of the telescopic adjusting rod 2 in this embodiment allows the same tooling to adapt to the measurement reference length of ring-shaped parts of different sizes and specifications, improving the tooling's versatility and economic efficiency. The high stability of the locking buckle 23 ensures that no unexpected displacement will occur due to the measuring force during the measurement process, providing mechanical protection for maintaining measurement accuracy. Compared with traditional multi-section telescopic structures, the telescopic adjusting rod 2 in this embodiment has better bending stiffness and smaller cumulative error, ensuring that the measuring contact point is always kept on the designed measuring axis, providing measurement accuracy for the inner groove of the ring-shaped part.

[0044] To further improve the operating accuracy and stability of the telescopic adjustment rod 2, a guide groove 212 is formed on the side wall of the hollow rod 21 along the axial direction of the hollow rod 21, and a first guide pin 221 is provided on the outer peripheral surface of the end of the solid rod 22, and the first guide pin 221 is movably disposed in the guide groove 212.

[0045] It is understood that in this embodiment, a guide mechanism is added to the mating structure of the hollow rod 21 and the solid rod 22 of the telescopic adjustment rod 2. Specifically, please refer to [link to documentation]. Figure 2As shown, a guide groove 212 is machined along the axial direction on the side wall of the hollow rod 21, and the guide groove 212 penetrates the side wall of the hollow rod 21. At the same time, a first guide pin 221 is radially inserted at the corresponding end of the solid rod 22. The end of the first guide pin 221 is precisely embedded in the guide groove 212 of the hollow rod 21 and can slide freely along the axial direction in the groove.

[0046] When the operator pushes the solid rod 22 for telescopic adjustment, the first guide pin 221 moves along the trajectory of the guide groove 212, effectively limiting the circumferential rotation and radial offset of the solid rod 22 within the hollow rod 21, ensuring that the two always maintain strict axial relative movement. The length of the guide groove 212 determines the maximum adjustment stroke of the solid rod 22, while its width and the clearance between it and the first guide pin 221 are precisely calculated to ensure smooth sliding while minimizing wobbling space.

[0047] By setting a guide mechanism for the telescopic adjustment rod 2, the rotation of the solid rod 22 that may occur during the adjustment process can be eliminated, ensuring the consistency of the measurement end direction, significantly improving the linear accuracy of the adjustment action, enabling the operator to control the telescopic length more precisely, and reducing measurement system errors caused by rod misalignment; at the same time, the cooperation between the first guide pin 221 and the guide groove 212 also plays an auxiliary bearing role, sharing the lateral force that may be generated during measurement, enhancing the bending stiffness of the entire telescopic adjustment rod 2, and further improving the overall stability and service life of the measurement system.

[0048] In some embodiments of the measuring fixture of the present invention for measuring the inner groove of an annular component, combined with Figure 1 and Figure 3 As shown, the measuring body 3 is a frame-shaped component. The first end of the frame-shaped component is connected to the telescopic adjustment rod 2, and the second end of the frame-shaped component is provided with a sleeve assembly 6. The dial indicator 4 is located inside the frame-shaped component, and the sleeve around the measuring head of the dial indicator 4 is connected to the sleeve assembly 6. The measuring head of the dial indicator 4 is located inside the sleeve assembly 6. The extension rod 5 is movably inserted through the sleeve assembly 6 and is fixedly connected to the measuring head of the dial indicator 4 inside the sleeve assembly 6.

[0049] Understandably, the structure of the measuring body 3 is crucial to ensuring accurate force transmission and operational rigidity. In this embodiment, the measuring body 3 adopts a frame structure, with one end fixedly connected to the telescopic adjustment rod 2 and the other end precisely fitted with a sleeve assembly 6. The dial indicator 4 is completely housed and fixed inside this rigid frame, and the measuring head of the dial indicator 4 passes through the sleeve assembly 6; the extension rod 5 is coaxially inserted into the sleeve assembly 6 and is fixedly connected to the measuring head of the dial indicator 4.

[0050] When the measuring end of the extension rod 5 contacts the workpiece, the resulting minute displacement is directly and without attenuation converted into the linear motion of the dial indicator 4's measuring head through its rigid connection with the head, thereby driving the dial pointer to display accurately. The frame-type main body provides a stable mounting reference and torsional support for the entire transmission chain, while the sleeve assembly 6 plays a precise guiding and limiting role for the reciprocating motion of the extension rod 5, ensuring that its motion trajectory coincides with the measuring axis of the dial indicator 4.

[0051] In this embodiment, the high rigidity of the frame structure of the measuring body 3 effectively suppresses structural deformation that may occur during the measurement process, greatly reducing measurement errors caused by the deflection of the body. The dial indicator 4 is built into the enclosed frame, forming good physical protection, avoiding damage from impacts, and preventing on-site contaminants such as chips and oil from directly affecting the instrument, thus improving the durability and reliability of the equipment. Most importantly, in this embodiment, the measuring body 3, sleeve assembly 6, and extension rod 5 form an integrated guiding design, ensuring the shortest and most direct transmission path of the measuring force, significantly improving the sensitivity and repeatability of the entire system, and enabling stable and reliable capture and display of even micron-level dimensional deviations in the groove of the annular component.

[0052] See some specific examples. Figure 4 As shown, the sleeve assembly 6 includes a connecting sleeve 61, a limiting nut 62, and a locking nut 63. The connecting sleeve 61 passes through the second end of the measuring body 3, and a limiting step is formed on the outer circumferential surface of the connecting sleeve 61. The limiting nut 62 is sleeved on the outer circumferential surface of the connecting sleeve 61. The limiting nut 62 and the limiting step of the connecting sleeve 61 are located on the inner and outer sides of the second end of the measuring body 3, respectively, for clamping the measuring body 3. The locking nut 63 is sleeved on the end of the connecting sleeve 61 facing the dial indicator 4, for locking and fixing the sleeve on the outer circumference of the measuring head of the dial indicator 4 to the end of the connecting sleeve 61.

[0053] Understandably, the structure of the sleeve assembly 6 is central to achieving both precision measurement and convenient maintenance. In this example, as... Figure 4 As shown, the sleeve assembly 6 consists of a connecting sleeve 61, a limiting nut 62, and a locking nut 63. The connecting sleeve 61 passes through the mounting hole at the end of the frame-shaped part of the measuring body 3, and a raised limiting step is machined on its outer circumferential surface. The limiting nut 62 is screwed onto the connecting sleeve 61, and by cooperating with the limiting step located on the inner side of the frame-shaped part, it tightly clamps the mounting part of the frame-shaped part from both the inside and outside, thereby firmly fixing the connecting sleeve 61 to the measuring body 3. The locking nut 63 is installed at the end of the connecting sleeve 61 facing the dial indicator 4, and is used to fasten the sleeve on the outer circumference of the measuring head of the dial indicator 4 to this end, completing the final installation of the dial indicator 4.

[0054] During assembly, first, pass the connecting sleeve 61 through the measuring body 3, screw the limiting nut 62 into the frame from the inside and tighten it to quickly and rigidly fix the sleeve assembly 6 onto the body. Then, insert the measuring head of the dial indicator 4 into the connecting sleeve 61, and use the locking nut 63 to press the outer sleeve end face of the measuring head of the dial indicator 4 against the end of the connecting sleeve 61 to ensure the axial positioning and circumferential anti-rotation of the dial indicator 4.

[0055] The double-nut locking structure (limit nut 62 and locking nut 63) provides connection rigidity and stability, effectively eliminating any slight loosening that may occur during measurement and ensuring the absolute reliability of the measurement force transmission path. The limiting step on the connecting sleeve 61 and the mounting hole on the measuring body 3 constitute precise axial positioning, ensuring that the axis of the sleeve assembly 6 and the internal extension rod 5 maintains the precise spatial relationship required by the design with the reference plane of the measuring body 3. The sleeve assembly 6 structure in this example allows the dial indicator 4 to be disassembled, replaced, or calibrated without disassembling the entire sleeve assembly 6, making maintenance extremely convenient and significantly improving the maintainability and service life of the tooling.

[0056] Further, see also Figure 4 As shown, a spring 7 is sleeved around the measuring head of the dial indicator 4. The first end of the spring 7 abuts against the sleeve around the measuring head of the dial indicator 4, and the second end of the spring 7 abuts against the extension rod 5. An elongated hole is formed on the extension rod 5 along the axial direction of the extension rod 5. A second guide pin 8 is passed through the connecting sleeve 61 and is movably disposed in the elongated hole of the extension rod 5.

[0057] Understandably, this example incorporates a synergistic design of elastic reset and precise guidance in the connection mechanism between the measuring head of dial indicator 4 and the extension rod 5. For example... Figure 4 As shown, a spring 7 is fitted around the outer periphery of the dial indicator 4 measuring head. The two ends of the spring 7 abut against the sleeve on the outer periphery of the dial indicator 4 measuring head and the inner end face of the extension rod 5, respectively, forming an elastic preload system. At the same time, an elongated hole is machined along the axial direction on the extension rod 5, and a second guide pin 8 is radially inserted through the corresponding position of the connecting sleeve 61. The end of the second guide pin 8 extends into the elongated hole of the extension rod 5.

[0058] In the non-measuring or non-installation state, the preload of spring 7 pushes the extension rod 5 away from the dial indicator until one end of the elongated hole on the extension rod 5 contacts the second guide pin 8. At this point, the extension rod 5 is in a defined initial extended position, facilitating quick alignment with the workpiece. When measuring, the operator places the measuring fixture into the groove inside the annular part. After the measuring end of the extension rod 5 contacts the side wall of the workpiece, it is compressed inward. Spring 7 is further compressed, while the second guide pin 8 slides within the elongated hole, providing a constant and moderate measuring force and ensuring the linear reciprocating motion of the extension rod 5.

[0059] It is important to understand that the constant measuring force provided by spring 7 avoids measurement errors introduced by uneven manual pressing pressure, ensuring consistency of contact conditions for each measurement. The cooperation between the second guide pin 8 and the elongated hole allows necessary axial movement of the extension rod 5 while strictly limiting its radial runout and circumferential rotation, ensuring the linearity of the extension rod 5's movement and the stability of the measurement contact point's posture. Ultimately, this constitutes a precision measurement execution terminal with flexible force application and rigid guidance, which not only improves the accuracy, repeatability, and reliability of measurements but also makes the operation smoother and more stable, significantly reducing the skill threshold and labor intensity for operators.

[0060] In some embodiments of the measuring fixture of the present invention for measuring the groove inside a ring-shaped part, see again Figure 1 As shown, the measuring reference base 1 includes a base 11, two positioning blocks 12 and a handle 13. The two positioning blocks 12 are fixed on the base 11 and are arranged opposite to each other. The opposite surfaces of the two positioning blocks 12 form two reference surfaces. The handle 13 is fixedly connected to the base 11.

[0061] Understandably, the measuring reference base 1, as the traceability reference of the entire measuring fixture, is crucial to ensuring measurement accuracy due to its structural design. In this embodiment, the measuring reference base 1 mainly consists of a base 11, two positioning blocks 12, and two handles 13. The base 11 serves as a stable mounting platform, with its lower surface precision-machined to ensure stable placement. The two positioning blocks 12 are vertically fixed to the upper surface of the base 11 at a fixed interval. Their opposing inner working surfaces undergo high-precision quenching or surface nitriding treatment, achieving a flatness of less than 0.05 mm, forming two reference surfaces with high parallelism and excellent flatness. The precise distance between these two reference surfaces is the known reference distance. Furthermore, handles 13 are fixedly installed at both ends of the base 11 to facilitate the operator's movement and positioning of the reference base.

[0062] Before use, the operator can easily place the entire measuring reference base 1 onto the measuring platform or workbench using handle 13. The fixed installation of the two positioning blocks 12 ensures the permanence and immutability of the reference distance, eliminating errors caused by assembly gaps or repeated adjustments. When the moving measuring mechanism needs calibration, simply place its measuring ends against these two precision-machined reference surfaces to quickly establish the zero point of the measurement.

[0063] It is important to understand that the separate reference base design in this embodiment separates the high-precision reference system from the frequently used measuring mechanism, avoiding the impact of bumps, vibrations, and other factors during measurement operations on the long-term stability of the reference, effectively protecting the reference accuracy. The fixed reference distance eliminates the tedious calibration steps before each use, simplifying the operation process and improving measurement efficiency, making it particularly suitable for rapid batch inspection in production environments. The addition of handle 13 not only facilitates movement but also reduces the temperature effects or contamination that may result from direct hand contact with the reference base body, further ensuring the reliability of the reference. Overall, the measurement reference base 1 in this embodiment, through structural optimization, provides a stable, accurate, and easy-to-use scale origin for the entire measurement system.

[0064] In some embodiments of the measuring fixture for measuring the groove inside a ring-shaped part according to the present invention, the second end of the telescopic adjustment rod 2 and the second end of the extension rod 5 are formed with vertical folding portions, which are used to adapt to the measuring space of the groove inside the ring-shaped part to be measured.

[0065] Understandably, to address the accessibility issue of the measurement contact point caused by the narrow and deep structure of the groove within the annular component, the measuring ends of the telescopic adjustment rod 2 and the extension rod 5 in this embodiment have been adaptively designed. In some specific examples, such as... Figure 1 As shown, the second end of the telescopic adjustment rod 2 and the second end of the extension rod 5 are not simply straight rod ends, but are machined with a vertical bend. This bend causes the measuring contact to turn from the axial end of the rod to the radial side, forming a measuring head similar to an L-shape or a hook.

[0066] In certain measurement scenarios, when it is necessary to measure the groove deep inside or on the side of a ring-shaped workpiece, the measuring end with the vertical bend can easily extend into the inner hole of the ring-shaped workpiece, and the side end face of the bend can accurately abut against the side wall of the groove, avoiding the interference of the inner hole wall or other structures of the workpiece on the straight path of the measuring rod, so that the measuring contact can directly and stably contact the measuring position that is difficult to reach with traditional straight rods.

[0067] The adaptive structural design of the measuring ends of the telescopic adjustment rod 2 and the extension rod 5 in this embodiment enhances the adaptability of the measuring fixture to complex workpiece structures. In particular, it solves the measurement challenges of deep grooves, blind grooves, or annular parts with shoulder obstructions, expanding the fixture's versatility. The folding structure allows for a more rational direction of the measuring force, contributing to stable gripping of the fixture during measurement and reducing force errors caused by rod tilting. Most importantly, this design ensures that the measuring contact point is in the correct posture (typically planar contact) against the sidewall of the groove, rather than point contact, resulting in a more stable and accurate dimensional reflection, further improving the reliability and accuracy of the measurement.

[0068] In another aspect, the present invention provides a method for measuring the inner groove of an annular part, applicable to the measuring fixture for measuring the inner groove of an annular part in any of the above embodiments or examples. In some embodiments, the method for measuring the inner groove of an annular part includes the following steps S1 to S4.

[0069] S1. Place the measuring reference pedestal 1 on the platform.

[0070] Specifically, the measuring reference base 1 is placed stably on the measuring platform or a clean workbench. The precision-machined surface of the measuring reference base 1 ensures the stability of the placement, and the two positioning blocks 12 on it form a known and fixed reference distance (e.g., 489 mm), providing a traceable dimensional origin for the entire measurement process.

[0071] S2. By adjusting the telescopic adjustment rod 2, the second end of the telescopic adjustment rod 2 and the second end of the extension rod 5 are respectively abutted against the two reference surfaces of the measuring reference base 1, so that the movable measuring mechanism is in the reference state at the reference distance, and the dial indicator 4 is zeroed.

[0072] Step S2 primarily utilizes a high-precision mechanical reference to perform on-site zero-point calibration of the measurement system, thereby correlating all subsequent measurements to this reference and eliminating the instrument's own systematic errors. Specifically, by holding the movable measuring mechanism and adjusting the length of its telescopic adjustment rod 2, the second end of the telescopic adjustment rod 2 (e.g., the measuring head with a vertical folding section) and the second end of the extension rod 5 are securely abutted against the two reference surfaces of the measuring reference base 1, respectively. At this time, the span of the movable measuring mechanism is precisely set to a known reference distance; this state is the reference state of the movable measuring mechanism. Maintaining this state, the pointer of the dial indicator 4 is adjusted to zero.

[0073] S3. The measuring mechanism in the reference state measures the groove inside the ring-shaped part to be measured. The second end of the telescopic adjustment rod 2 and the second end of the extension rod 5 are respectively abutted against the groove inside the ring-shaped part to be measured, and the display value of the dial gauge 4 is read.

[0074] Specifically, keeping the moving measuring mechanism in its zeroed-out reference state, move it to the annular workpiece to be measured. First, place the telescopic adjustment rod 2 against one side of the inner wall of the groove within the annular workpiece. Then, adjust the measuring end of the extension rod 5 to contact the opposite side of the inner wall of the groove. During this process, the compression or extension of the extension rod 5 will drive the pointer of the dial indicator 4 to deflect through its rigid connection with the measuring head. After the measuring head has made stable contact, directly read the value displayed on the dial of the dial indicator 4. This reading is the deviation of the actual size of the workpiece groove from the reference distance.

[0075] S4. Calculate the actual size of the groove inside the annular part to be measured based on the reference distance and the displayed value of the dial gauge 4.

[0076] Based on the reference distance (set as) ) and the deviation value read from the dial indicator (set as ) (Positive and negative signs represent directions), and the actual dimensions of the groove inside the annular part can be calculated. When calculating, pay attention to the dimensional increments and decrements represented by the positive and negative signs of the dial indicator reading. Compare the calculation results with the tolerance requirements on the drawing to quickly determine whether the workpiece is qualified.

[0077] It is understood that the measurement method for the inner groove of the annular part in this embodiment only needs to be performed once in the entire measurement batch (or repeated during periodic calibration) based on the reference state established in step S2 above. Subsequent measurements for each workpiece only require simple steps S3 and S4. This greatly improves the efficiency of batch inspection. At the same time, since the measurement process is based on a stable mechanical reference and a uniform measurement posture, the results have good repeatability and high accuracy. This effectively solves the problems of large measurement errors of traditional calipers, cumbersome operation of general measuring tools, and inconsistent results, and realizes efficient and accurate quality control of the inner groove size of the annular part on the production site.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A measuring fixture for measuring the inner groove of a ring-shaped part, characterized in that, include: The measuring reference base (1) includes two opposing reference surfaces, and the distance between the two reference surfaces is the reference distance; The movable measuring mechanism includes a telescopic adjusting rod (2), a measuring body (3), a dial indicator (4), and an extension rod (5). The first end of the telescopic adjusting rod (2) is fixedly connected to the first end of the measuring body (3). The dial indicator (4) is fixed to the measuring body (3), and the measuring head of the dial indicator (4) is movably inserted through the second end of the measuring body (3). The first end of the extension rod (5) is connected to the measuring head of the dial indicator (4). The active measuring mechanism includes a reference state and a measuring state. In the reference state, the second end of the telescopic adjusting rod (2) and the second end of the extension rod (5) respectively abut against the two reference surfaces of the measuring reference seat (1). In the measuring state, the second end of the telescopic adjusting rod (2) and the second end of the extension rod (5) respectively abut against the inner groove of the annular part to be measured.

2. The measuring fixture for measuring the inner groove of an annular part according to claim 1, characterized in that, The telescopic adjusting rod (2) includes: Hollow rod (21), the first end of which is fixedly connected to the first end of the measuring body (3), and the side wall of the second end of the hollow rod (21) is formed with an adjustment slot (211) arranged along the axial direction of the hollow rod (21). A solid rod (22) is movably inserted through the second end of the hollow rod (21); A locking buckle (23) is fitted onto the outer circumferential surface of the second end of the hollow rod (21) to adjust the inner diameter of the hollow rod (21) in order to lock the hollow rod (21) and the solid rod (22).

3. The measuring fixture for measuring the inner groove of an annular part according to claim 2, characterized in that, The hollow rod (21) has a guide groove (212) formed on its side wall along the axial direction of the hollow rod (21), and a first guide pin (221) is provided on the outer peripheral surface of the end of the solid rod (22), and the first guide pin (221) is movably disposed in the guide groove (212).

4. The measuring fixture for measuring the inner groove of an annular part according to claim 1, characterized in that, The measuring body (3) is a frame-shaped component. The first end of the frame-shaped component is connected to the telescopic adjustment rod (2). The second end of the frame-shaped component is provided with a sleeve assembly (6). The dial indicator (4) is located inside the frame-shaped component. The sleeve around the measuring head of the dial indicator (4) is connected to the sleeve assembly (6). The measuring head of the dial indicator (4) is located inside the sleeve assembly (6). The extension rod (5) is movably inserted through the sleeve assembly (6) and is fixedly connected to the measuring head of the dial indicator (4) inside the sleeve assembly (6).

5. The measuring fixture for measuring the inner groove of an annular part according to claim 4, characterized in that, The sleeve assembly (6) includes: A connecting sleeve (61) is inserted through the second end of the measuring body (3), and a limiting step is formed on the outer circumferential surface of the connecting sleeve (61); A limiting nut (62) is sleeved on the outer circumferential surface of the connecting sleeve (61). The limiting steps of the limiting nut (62) and the connecting sleeve (61) are located on the inner and outer sides of the second end of the measuring body (3) respectively, and are used to clamp the measuring body (3). A locking nut (63) is fitted onto the end of the connecting sleeve (61) facing the dial indicator (4) to lock and fix the sleeve on the outer periphery of the measuring head of the dial indicator (4) to the end of the connecting sleeve (61).

6. The measuring fixture for measuring the inner groove of an annular part according to claim 5, characterized in that, A spring (7) is sleeved on the outer periphery of the measuring head of the dial indicator (4). The first end of the spring (7) abuts against the sleeve on the outer periphery of the measuring head of the dial indicator (4), and the second end of the spring (7) abuts against the extension rod (5). The extension rod (5) has an elongated hole arranged along the axial direction of the extension rod (5), and the connecting sleeve (61) is provided with a second guide pin (8), which is movably disposed in the elongated hole of the extension rod (5).

7. The measuring fixture for measuring the inner groove of an annular part according to any one of claims 1 to 6, characterized in that, The measuring reference base (1) includes: Base (11); Two positioning blocks (12) are fixed on the base (11). The two positioning blocks (12) are arranged opposite to each other, and the opposite surfaces of the two positioning blocks (12) form two reference surfaces. The handle (13) is fixedly connected to the base (11).

8. The measuring fixture for measuring the inner groove of an annular part according to any one of claims 1 to 6, characterized in that, The second end of the telescopic adjustment rod (2) and the second end of the extension rod (5) have vertical folding portions, which are used to adapt to the measurement space of the inner groove of the annular part to be measured.

9. The measuring fixture for measuring the inner groove of an annular part according to any one of claims 1 to 6, characterized in that, The second end of the telescopic adjustment rod (2), the second end of the extension rod (5), and the two opposing reference surfaces of the measuring reference base (1) are all subjected to quenching or surface nitriding treatment, and the flatness of the two opposing reference surfaces of the measuring reference base (1) is less than 0.05 mm.

10. A method for measuring the groove inside a ring-shaped component, characterized in that, The measuring fixture for measuring the inner groove of an annular part according to any one of claims 1 to 9 includes: Place the measuring reference base (1) on the platform; By adjusting the telescopic adjustment rod (2), the second end of the telescopic adjustment rod (2) and the second end of the extension rod (5) are respectively brought into contact with the two reference surfaces of the measuring reference base (1), so that the movable measuring mechanism is in the reference state at the reference distance, and the dial indicator (4) is zeroed. The inner groove of the ring-shaped part to be tested is measured by the active measuring mechanism in the reference state. The second end of the telescopic adjustment rod (2) and the second end of the extension rod (5) are respectively abutted against the inner groove of the ring-shaped part to be tested, and the display value of the dial indicator (4) is read. The actual size of the groove inside the annular part to be measured is calculated based on the reference distance and the reading of the dial gauge (4).

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