A dial gauge auxiliary base for plane push measurement and its use method

Abstract

A dial gauge auxiliary base for flatness measurement and its use method, which comprises an integral L-shaped body, the bottom surface of the shorter end is a precisely processed reference plane for smooth sliding on the surface of a workpiece; the top surface of the longer end is provided with a through hole penetrating in the vertical direction for inserting the dial gauge stem; the side wall is provided with a threaded hole vertically communicating with the through hole for screwing in a fastening bolt to lock the dial gauge. The perpendicularity of the through hole axis to the bottom surface is ≤0.1mm, and the roughness Ra of the bottom surface is ≤0.8μm. In use, the dial gauge is inserted into the through hole and locked, and the base is pushed to slide on the surface of the workpiece to continuously measure the flatness, step height and recess depth. The reference plane and clamping function are integrated in the integral structure, the assembly cumulative error is eliminated, and the advantages of simple structure, stable measurement, small and portable, low cost are achieved.

Description

Technical Field

[0001] This invention belongs to the field of mechanical measuring tool technology, specifically relating to a dial indicator auxiliary base for planar displacement measurement and its usage method, which can be used with a dial indicator to conveniently measure the flatness, step height and recess depth of a workpiece. Background Technology

[0002] In machining and assembly processes, measuring the dimensional accuracy of workpieces, especially flatness, step height, and surface roughness, is an essential step. Dial indicators, as high-precision general-purpose measuring tools, are widely used in these measurement tasks. However, when used alone, it is difficult to keep a dial indicator stable on a plane while maintaining the direction of its measuring rod perpendicular to the reference plane for continuous measurement.

[0003] Currently, the following solutions are mainly used in engineering practice to address the above problems:

[0004] Firstly, the dial indicator can be fixed to a dedicated measuring stand or marble platform. While such devices can provide a stable measurement reference, they are usually bulky, heavy, inconvenient to carry, and difficult to use in confined spaces or on-site measurement environments.

[0005] Secondly, specialized measuring tools integrating guide rails, sliders, and other mechanisms are used. For example, some solutions achieve the translation of the dial indicator by setting up a guide rail and slider, or achieve height adjustment and measurement through a base, column, and slider structure. However, these tools are often complex in structure, have many parts, high manufacturing costs, and still lack portability.

[0006] Third, magnetic bases and other adsorption-type fixing devices are used. Although such devices are convenient and flexible, their adsorption stability is greatly affected by the workpiece material and surface condition, limiting their applicability in scenarios requiring continuous measurement.

[0007] In addition, there are dedicated height gauges or depth gauges on the market, but their functions are relatively limited, they are usually only applicable to specific types of size measurements, and they are more expensive.

[0008] In summary, there is an urgent need for an auxiliary tool that is simple in structure, easy to use, low in cost, and can be used with a dial indicator to achieve stable planar displacement measurement, in order to make up for the shortcomings of existing technical solutions. Summary of the Invention

[0009] While existing technologies using dedicated measuring brackets or marble platforms can provide a stable reference, they are bulky, heavy, inconvenient to carry, and unsuitable for confined spaces or on-site measurement environments. Magnetic bases and other adsorption-type fixing devices are highly susceptible to the stability of the workpiece material and surface condition, making them unsuitable for scenarios requiring continuous movement measurements. Dedicated height gauges or depth gauges offer limited functionality and are costly. This invention provides a dial indicator auxiliary base for planar movement measurements and its usage method. Through an integrated, compact structural design, the dial indicator is securely fixed to a smoothly sliding reference base, achieving high-precision, portable, and multifunctional planar movement measurements.

[0010] To achieve the above objectives, the present invention adopts the following technical solution:

[0011] A dial indicator auxiliary base for plane displacement measurement, characterized in that it includes:

[0012] The L-shaped body is integrally formed, having a shorter end and a longer end. The bottom surface of the shorter end is a precision-machined reference plane for smooth sliding on the surface of the workpiece to be measured. The top surface of the longer end has a through hole extending vertically, with a preset perpendicularity requirement between the axis of the through hole and the reference plane of the bottom surface. The through hole is used for inserting the dial indicator rod. The side wall of the L-shaped body also has a threaded hole communicating with the through hole. The axis of the threaded hole intersects and is perpendicular to the axis of the through hole. The threaded hole is used to screw in a fastening bolt to lock and fix the dial indicator rod in the through hole.

[0013] As a further limitation of the above technical solution, the perpendicularity between the axis of the through hole and the reference plane of the bottom surface is not greater than 0.1 mm; in another preferred embodiment, the perpendicularity is not greater than 0.02 mm.

[0014] As a further limitation of the above technical solution, the surface roughness Ra of the bottom surface is ≤0.8μm.

[0015] As a further limitation of the above technical solution, the upper edge of the through hole is provided with a radial groove along the axial direction. The radial groove is used to provide elastic deformation space when the fastening bolt is tightened, so that the inner wall of the through hole will generate radial elastic contraction to evenly grip the dial indicator rod.

[0016] As a further limitation of the above technical solution, the inner diameter of the through hole is adapted to the outer diameter of the universal dial indicator sleeve, and its inner hole tolerance zone is H7 grade.

[0017] As a further limitation of the above technical solution, the L-shaped body is made of metal material and undergoes overall quenching and deep cryogenic aging treatment, with a hardness of HRC 55~60.

[0018] As a further limitation of the above technical solution, the L-shaped body, except for the bottom surface, is provided with a rust-proof treatment layer.

[0019] As a further limitation of the above technical solution, a replaceable variable diameter bushing is provided in the through hole, which is used to adapt to dial indicator rods with different outer diameter specifications.

[0020] The present invention also provides a method for using the dial indicator auxiliary base for planar displacement measurement described above, comprising the following steps:

[0021] Insert the dial indicator rod into the through hole of the L-shaped body, and adjust the insertion depth of the dial indicator so that the dial indicator probe is lower than the bottom surface;

[0022] Screw the fastening bolt into the threaded hole so that the fastening bolt abuts against the dial indicator rod, and fix the dial indicator to the L-shaped body;

[0023] Place the bottom surface of the L-shaped body on the standard zeroing reference surface and adjust the dial of the dial indicator to zero it;

[0024] The zeroed bottom surface is placed on the surface of the workpiece to be tested, and the L-shaped body is pushed to slide smoothly on the surface of the workpiece.

[0025] By reading the changes in the dial indicator reading, the measurement results of the flatness, step height, or depression depth of the workpiece under test can be obtained.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] 1. Simple structure and low cost: It adopts a single-piece design, which simplifies the processing steps and reduces manufacturing costs.

[0028] 2. Easy to use and versatile: Simply insert the dial indicator into the base and tighten the screw to use it. It can be used to measure flatness, step height, and surface roughness, making it a multi-purpose device.

[0029] 3. Stable measurement and high accuracy: The precision-machined plane at the bottom of the main body provides a stable reference for measurement. Combined with the high precision of the dial indicator, accurate and reliable measurement can be achieved.

[0030] 4. Compact and portable with strong applicability: Small in size and light in weight, it is easy to carry and use in various environments such as workshops and on-site. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the auxiliary base of the dial indicator for plane displacement measurement according to the present invention; wherein, a is the main view and b is the AA sectional view.

[0032] Figure 2 This is a schematic diagram showing the usage state of the present invention after it is assembled with a dial indicator.

[0033] In the diagram: 1. Main body; 2. Dial indicator; 3. Fastening bolts. Detailed Implementation

[0034] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0035] Please see Figure 1 and Figure 2 As shown in the figure, the dial indicator auxiliary base for planar displacement measurement includes an L-shaped main body 1; the L-shaped main body 1 has a shorter end and a longer end; wherein, the bottom surface of the shorter end of the main body 1 (i.e., Figure 2 The bottom surface a) shown is the measurement reference plane of this invention; a dial indicator mounting through hole (i.e., ...) is provided at the top surface of the longer end of the main body 1. Figure 2 The through hole b shown is designed to be the diameter of a standard dial indicator probe. The perpendicularity between the central axis of the through hole b and the bottom surface a is required to be controlled within 0.1 mm (i.e., within a 100 mm measurement range, the offset of the axis relative to the normal to the bottom surface is no greater than 0.1 mm). In another preferred embodiment, to further improve measurement accuracy, this perpendicularity can preferably be controlled within 0.02 mm. The significance of ensuring perpendicularity lies in the fact that when the dial indicator probe moves up and down with the undulations of the workpiece surface, if the axis of the through hole is not perpendicular to the reference bottom surface, there will be an angle between the probe's movement direction and the measurement direction, introducing a cosine error. Taking a perpendicularity of 0.1 mm and a dial indicator travel of 10 mm as an example, the measurement error introduced by this angle is approximately 0.005 mm, which is not negligible for high-precision measurements. Therefore, this solution strictly controls the perpendicularity within 0.1 mm or even 0.02 mm, fundamentally eliminating this systematic error.

[0036] The through hole b is located on the top surface of the longer end of the L-shaped body 1. The distance from the axis of the through hole b to the bottom surface a and to the side of the longer end of the L-shaped body must ensure that, after installation, the axis of the measuring probe of the dial indicator 2 is approximately 0.5mm to 1.0mm lower than the bottom surface a in its free state. This ensures that the probe can reliably contact the measured surface and has sufficient initial compression when the reference surface is in contact with the workpiece. This relative positional relationship is directly guaranteed by coordinate positioning during machining, eliminating the need for user adjustment during use.

[0037] A threaded hole perpendicular to the axis of the through hole b is provided on the side of the main body 1 (specifically, at the radial position at the front end or one side of the through hole b). Figure 2The threaded hole c is shown in the figure. This threaded hole is preferably an M6×1.0 fine thread to provide a large locking torque and good self-locking performance. To further improve the uniformity and reliability of clamping, this embodiment has a slender elastic deformation groove (i.e., a radial groove, not otherwise marked in the figure) axially formed on the upper edge of the through hole b. The width of this elastic groove is preferably 1mm~2mm, and the depth extends downward from the upper edge of the through hole to approximately 3mm~5mm below the center line of the threaded hole. When the fastening bolt 3 is screwed into the threaded hole c and presses against the inner wall of the through hole b, the elastic groove allows the inner wall of the through hole to undergo a slight radial elastic contraction (the contraction amount is approximately 0.02mm~0.05mm), thereby ensuring that the dial indicator 2's rod is uniformly and firmly clamped.

[0038] Compared to the traditional single-point force application method where the set screw directly clamps the dial indicator rod, the elastic deformation groove structure of this solution has the following outstanding advantages: First, it ensures that the clamping force is evenly distributed along the circumference of the dial indicator rod, avoiding microscopic bending deformation or axial misalignment of the measuring rod caused by unilateral force; Second, the elastic contraction provides adaptive clamping force compensation, so even if slight loosening occurs due to temperature changes or vibration during use, the elastic recovery force can still maintain a certain clamping effect, effectively preventing axial movement or circumferential rotation loosening of the dial indicator rod during measurement; Third, it reduces the contact stress of the set screw directly acting on the surface of the dial indicator rod, preventing pits or scratches from being pushed out of the outer wall of the dial indicator rod, thus protecting the accuracy of the dial indicator.

[0039] like Figure 2 As shown, during assembly, the operator inserts the sleeve rod of dial indicator 2 into the through hole b of the push block body 1 from top to bottom. Adjust the insertion depth of dial indicator 2 according to the size range of the workpiece to be measured, so that the measuring probe of dial indicator 2 is approximately 0.5mm to 1.0mm below the bottom surface a in its free state (to ensure that the probe can reliably contact the measured surface and has sufficient initial compression when the reference surface is in contact with the workpiece). After adjustment, screw the fastening bolt 3 into the threaded hole c and apply an appropriate tightening torque (preferably 2 to 3 N·m) to securely lock dial indicator 2. Excessive tightening torque may cause plastic deformation of the inner wall of the through hole or seizing deformation of the dial indicator rod; insufficient torque will result in insufficient clamping force. Therefore, a torque range of 2 to 3 N·m is the preferred value.

[0040] Before formal measurement, a "zeroing" operation is required: Place the assembled base of this invention on a cleaned standard zeroing plate (or a reference surface on the workpiece itself that is not worn), ensuring that the bottom surface a is completely in contact with the zeroing plate. At this time, the probe of dial indicator 2 is compressed to near the middle position of its working stroke (approximately 1 / 3 to 1 / 2 of the total stroke). Adjust the dial of dial indicator 2 so that the pointer points to "0" (or record the initial reading). This zeroing operation is an important prerequisite for ensuring the accuracy of subsequent relative height measurements, and it also verifies whether the dial indicator probe has sufficient compression stroke to cover the range of dimensions to be measured.

[0041] Example 1: Flatness Measurement

[0042] Place the zeroed base on the surface of the workpiece to be measured, and hold the long side wall of the push block body 1 (i.e., Figure 1 The dial indicator 2 slides smoothly along a straight line or grid path on the surface of the workpiece at a uniform and slow speed (approximately 30~50 mm / s) on the outer side of the vertical long side of the L-shaped main body. During this process, the probe of dial indicator 2 moves up and down with the microscopic undulations of the workpiece surface, and the operator directly reads the range of changes in the dial indicator pointer. The maximum difference in this range is the flatness error value of that area.

[0043] Typical application example: In the flatness inspection of a batch of precision valve body sealing surfaces, this base was used in conjunction with a digital micrometer with a graduation of 0.001mm. Five measuring points were taken along the sealing surface in a zigzag pattern. The readings at each point were -0.002mm, +0.003mm, -0.001mm, +0.004mm, and -0.003mm, with a maximum difference of 0.007mm. The flatness of the sealing surface was determined to meet the design requirement of ≤0.01mm. The entire measurement process took approximately 30 seconds, which is much faster than the on-machine inspection process of a traditional coordinate measuring machine.

[0044] Example 2: Step Height Measurement

[0045] Place the bottom surface a of the pusher block 1 stably on the higher reference plane of the step to be measured. At this time, the probe of dial indicator 2 contacts the lower step plane, and record the dial indicator reading R1 (e.g., R1 = +0.120 mm). Then, move the pusher block as a whole, placing the bottom surface a on the lower step plane, so that the probe of dial indicator 2 contacts the higher reference plane (at this time, the probe is further compressed), and record the reading R2 (e.g., R2 = +0.380 mm). The difference between the two readings, R2 - R1 = 0.260 mm, is the precise height difference between the two step planes.

[0046] Typical application example: In the step depth detection of mold cavity, this base was used with a dial indicator with a graduation value of 0.01mm to quickly measure the sinking depth of the bottom of the cavity relative to the parting surface. The deviation between the measured value and the design value (0.25mm) was only +0.010mm, which met the mold acceptance standard.

[0047] Example 3: Depression Depth Measurement

[0048] With the base surface 'a' spanning the recessed area (i.e., both ends of the base surface resting on the intact surfaces of the recessed edge), the probe of dial indicator 2 should extend precisely into the bottom of the recess. When placing the base surface 'a' on the intact surfaces of the recessed edge, first adjust the dial indicator reading to zero (or record the reading R0). Then, smoothly move the base so that the probe is aligned directly above the recess, and record the reading R1. The recess depth value D = R1 - R0 (the reading increases if the probe extends downwards). To ensure measurement accuracy, the opening size of the recessed area should be larger than the width of the base surface, allowing the base surface to reliably span the intact surfaces on both sides of the recess.

Claims

1. A dial gauge auxiliary base for plane displacement measurement, characterized in that, include: An integrally formed L-shaped body (1) has a shorter end and a longer end; wherein, the bottom surface of the shorter end is a reference plane for smooth sliding on the surface of the workpiece to be measured; the top surface of the longer end is provided with a through hole that runs vertically through the center, and the axis of the through hole has a preset perpendicularity requirement with the reference plane, and the through hole is used for inserting the rod of the dial indicator (2); the side wall of the L-shaped body (1) is also provided with a threaded hole that communicates with the through hole, the axis of the threaded hole intersects and is perpendicular to the axis of the through hole, and the threaded hole is used to screw in a fastening bolt (3) to lock and fix the rod of the dial indicator (2) in the through hole (b).

2. The dial indicator auxiliary base for planar displacement measurement according to claim 1, characterized in that, The perpendicularity between the axis of the through hole and the reference plane is no greater than 0.1 mm.

3. The dial indicator auxiliary base for planar displacement measurement according to claim 1, characterized in that, The upper edge of the through hole is provided with a radial groove along the axial direction. The radial groove is used to provide elastic deformation space when the fastening bolt (3) is tightened, so that the inner wall of the through hole will generate radial elastic contraction to uniformly hug the rod of the dial indicator (2).

4. The dial indicator auxiliary base for planar displacement measurement according to claim 1, characterized in that, The inner diameter of the through hole is adapted to the outer diameter of the universal dial indicator sleeve, and its inner hole tolerance zone is H7 grade.

5. The dial indicator auxiliary base for planar push-off measurements according to claim 1, characterized in that, The through hole (b) is provided with a replaceable variable diameter bushing, which is used to adapt to dial indicator rods with different outer diameter specifications.

6. A method of using the dial gauge auxiliary base for planar push measurement according to any one of claims 1-5, characterized in that, Includes the following steps: Insert the dial indicator (2) into the through hole of the L-shaped body (1), and adjust the insertion depth of the dial indicator (2) so that the dial indicator probe is lower than the bottom surface; Screw the fastening bolt (3) into the threaded hole so that the fastening bolt (3) abuts against the dial indicator (2) and fixes the dial indicator (2) onto the L-shaped body (1); Place the bottom surface of the L-shaped body (1) on the standard zeroing reference surface and adjust the dial of the dial indicator (2) to zero it; The zeroed bottom surface is placed on the surface of the workpiece to be tested, and the L-shaped body (1) is pushed to slide smoothly on the surface of the workpiece. Read the changes in the reading of the dial indicator (2) to obtain the measurement results of the flatness, step height or depression depth of the workpiece to be measured.

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