Drilling device for detecting residual stress of machine tool body

Abstract

The utility model discloses a drilling device for detecting residual stress of a machine tool body, belongs to the field of stress testing equipment, and aims to solve the problems in the prior art that residual stress measuring holes are drilled by adopting a blind hole method. Comprising a magnetic base, an XY-axis fine adjustment platform, a T-shaped plate, a vertical connecting plate and a drill bushing, the plane connecting plate is arranged on the magnetic base, the XY-axis fine adjustment platform is arranged on the plane connecting plate, the T-shaped plate is connected with the output end of the XY-axis fine adjustment platform, the vertical displacement mechanism is arranged on the T-shaped plate, the vertical connecting plate is connected with the output end of the vertical displacement mechanism, the drill bushing is connected with the vertical connecting plate, and a vertically-through positioning hole is formed in the drill bushing. And a hard alloy wear-resistant sleeve is embedded in the positioning hole. The drilling position adjusting precision is high, stable drilling driving force is provided by means of the self weight of the drilling motor, manual operation errors are reduced, the layer-by-layer drilling requirement is met, and compared with a traditional magnetic drilling frame, the efficiency is higher.

Description

TECHNICAL FIELD

[0001] The utility model belongs to machine tool manufacturing technical field, especially relate to a drilling device for machine tool bed residual stress detection. BACKGROUND

[0002] The universality and importance of residual stress problem have been increasingly understood by people. Residual stress has a significant influence on fatigue strength, stress corrosion, shape accuracy and the like of a component; and its formation varies with the material, shape, forming and machining process of the component. How to determine the size of residual stress, adjust the distribution of residual stress and reduce or eliminate the harm of residual stress to engineering has become a problem that people widely concern.

[0003] There are many test methods for residual stress, and the method widely used at present is the blind hole method. The basic principle of this test method is that a blind hole with a diameter of 1.5 mm and a depth of 2 mm is drilled on the measured component by mechanical processing, so that the hole edge generates corresponding displacement and strain due to the release of part of the stress. The displacement or strain is measured by using a resistance strain gauge, and the original stress at the processed part of the component is obtained through conversion.

[0004] From the experimental steps of the above-mentioned blind hole method for detecting residual stress, it can be seen that the key factors for ensuring the drilling precision, improving the detection accuracy, stability and efficiency by reducing or eliminating the manual operation error are to drill qualified holes and to ensure the concentricity of the drilling and the center of the strain gauge.

[0005] Therefore, when drilling for detecting residual stress by using the blind hole method, it is necessary to ensure the drilling precision by using a drilling device. At present, a commonly used drilling device is a magnetic seat drill stand.

[0006] The magnetic seat drill stand is suitable for planar measurement of ferromagnetic materials such as machine tool beds. The magnetic seat drill stand uses a gear and rack mechanism to adjust the horizontal position for drilling center positioning, and the positioning is not accurate. At the same time, manual drilling is required during the drilling process, and the driving force introduced by manual operation cannot be determined, and the driving force error is large. Moreover, the magnetic seat drill stand can only satisfy the drilling of holes with a specified depth of 2 mm, and cannot realize layer-by-layer drilling.

[0007] Layer-by-layer drilling refers to drilling at a specified depth, such as 0.25 mm per layer, and measuring the displacement and strain generated by the release of stress in each layer after each layer is drilled. Generally, 8 layers are drilled, and the total depth is 2 mm. After obtaining the displacement and strain generated in each layer, a series of formulas can be used to calculate the uniform residual stress containing the strain in each layer. The uniform residual stress has smaller error compared with the residual stress obtained by drilling a hole with a depth of 2 mm at one time, and the calculation result is closer to the true value.

[0008] Therefore, it is necessary to improve the existing drill stand structure to solve the problems of poor centering accuracy, large manual operation error and inability to perform layer-by-layer drilling. Utility model content

[0009] The utility model discloses a drilling device for machine tool bed residual stress detection, to solve the problem of the blind hole method drilling residual stress measurement hole in prior art.

[0010] A drilling device for machine tool bed residual stress detection, including magnetic base, plane connecting plate, XY axis fine adjustment platform, T plate, vertical displacement mechanism, vertical connecting plate and drill bushing, plane connecting plate sets up on magnetic base, XY axis fine adjustment platform sets up on plane connecting plate, and T plate is connected with the output end of XY axis fine adjustment platform, and vertical displacement mechanism sets up on T plate, and vertical connecting plate is connected with the output end of vertical displacement mechanism, and drill bushing is connected with vertical connecting plate, and is equipped with the positioning hole that goes through up and down on drill bushing.

[0011] Further, the model of vertical displacement mechanism is ELCSS16L-B2.5-30-S.

[0012] Further, the model of XY axis fine adjustment platform is LBY60-L-H.

[0013] Further, the external dimensions of magnetic base are 120mm * 55mm * 50mm.

[0014] Compared with prior art, the utility model has the beneficial effects that:

[0015] 1, select the big size magnetic base of internal permanent magnet bigger, the adsorbing force that makes magnetic base can reach 1500N, is used for the automatic drilling device of the utility model, and therefore the drilling device of the utility model is combined with the measured machine tool bed more firmly.

[0016] 2, the transmission component that the X-Y gear rack horizontal displacement platform in traditional magnetic seat adopts is gear and rack, is applicable to quick adjustment, is not suitable for precision positioning, and the accuracy is 0.1mm.The transmission component that XY axis fine adjustment platform in the utility model adopts is differential head, is suitable for the precision adjustment of 0.01mm unit.Therefore, the horizontal displacement adjustment accuracy of the drilling device of the utility model improves 10 times, and the adjustment accuracy is higher.

[0017] 3、The traditional magnetic seat drilling frame is matched with a drill rod and a low-speed electric hand drill, and a 2mm deep hole is drilled by manual operation, and the manual operation error is large; the drilling device adopts a vertical displacement mechanism matched with a high-speed drilling motor to drill holes, the drilling motor can provide stable drilling driving force by relying on its own weight, and reduces the manual operation error. At the same time, the traditional magnetic seat drilling frame cannot realize layer-by-layer drilling, and can only drill a 2mm deep hole for stress measurement at one time, the minimum feeding amount of the vertical displacement mechanism in the drilling device of the utility model is 0.002mm, meets the required 0.25mm feeding depth of each layer for conventional layer-by-layer drilling, so that the comprehensive stress error calculated subsequently is smaller. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is a structural schematic view of the device of the utility model;

[0019] Figure 2 is a structural schematic view of the magnetic base;

[0020] Figure 3 is a structural schematic view of the plane connecting plate;

[0021] Figure 4 is a structural schematic view of the XY axis fine adjustment platform;

[0022] Figure 5 is a structural schematic view of the T-shaped plate;

[0023] Figure 6 is a structural schematic view of the vertical displacement mechanism;

[0024] Figure 7 is a structural schematic view of the vertical connecting plate;

[0025] Figure 8 is a structural schematic view of the drill sleeve.

[0026] In the drawing, 1. magnetic base, 2. plane connecting plate, 3. XY axis fine adjustment platform, 4. T-shaped plate, 5. vertical displacement mechanism, 6. vertical connecting plate, 7. drill sleeve. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical scheme and advantages of the utility model more clear and obvious, the utility model will be described below through the specific embodiments shown in the drawings. However, it should be understood that these descriptions are only exemplary, and are not intended to limit the scope of the utility model. In addition, in the following description, the description of known structures and technologies is omitted to avoid unnecessary confusion of the concept of the utility model.

[0028] The connections mentioned in this utility model are divided into fixed connections and detachable connections. Fixed connections, also known as non-detachable connections, include but are not limited to conventional fixed connection methods such as folded connections, riveted connections, adhesive connections, and welded connections. Detachable connections include but are not limited to conventional disassembly methods such as bolt connections, snap-fit ​​connections, pin connections, and hinge connections. When a specific connection method is not explicitly defined, it is assumed that at least one existing connection method can be found to achieve this function, and those skilled in the art can choose according to their needs. For example, a welded connection can be chosen for a fixed connection, and a bolted connection can be chosen for a detachable connection.

[0029] The present invention will be further described in detail below with reference to the accompanying drawings. The following embodiments are explanations of the present invention, but the present invention is not limited to the following embodiments.

[0030] Example: Figures 1-8 As shown, a drilling device for detecting residual stress in a machine tool bed includes a magnetic base 1, a planar connecting plate 2, an XY-axis fine-tuning platform 3, a T-shaped plate 4, a vertical displacement mechanism 5, a vertical connecting plate 6, and a drill sleeve 7. The planar connecting plate 2 is mounted on the magnetic base 1, the XY-axis fine-tuning platform 3 is mounted on the planar connecting plate 2, the T-shaped plate 4 is connected to the output end of the XY-axis fine-tuning platform 3, the vertical displacement mechanism 5 is mounted on the T-shaped plate 4, the vertical connecting plate 6 is connected to the output end of the vertical displacement mechanism 5, and the drill sleeve 7 is connected to the vertical connecting plate 6. The drill sleeve 7 has a vertically penetrating positioning hole.

[0031] The switch knob on the magnetic base 1 can be turned to the + or - position, thereby controlling the permanent magnet inside to form a magnetic field or block the magnetic field. When the permanent magnet inside the magnetic base 1 forms a magnetic field, the magnetic base 1 can generate an attraction force of up to 1500N. It has a compact structure, strong magnetic force, and can be reliably fixed on the machine tool bed under test, such as the machine tool bed.

[0032] The four holes in the middle of the planar connecting plate 2 are used to connect to the magnetic base 1 by bolts, and the holes at the four corners of the planar connecting plate 2 are used to connect to the XY axis fine-tuning platform 3 by bolts.

[0033] The XY axis fine adjustment platform 3 is composed of two single-axis fine adjustment platforms which are connected by bolts. The single-axis fine adjustment platform includes a table, a base, balls, a differential head, a clamping mechanism and a friction locking mechanism. The table and the base are connected by adding balls in the groove of the lower part of the table and the groove of the upper part of the base. The balls are in contact with the track at 45 degrees. This structure can realize high-precision and smooth movement. The moving stroke of the table is ±6.5 mm. The friction locking mechanism is composed of a locking piece fixed on the side of the base and a locking screw. The locking piece is pressed by the locking screw to generate friction to fix the table. The clamping mechanism is composed of a clamping screw and a locking nut. The clamping screw is clamped on the L-shaped plate on the side of the table. The differential head is used to convert the rotary motion into linear insertion and withdrawal action. It converts the fine changes of rotation into linear insertion and withdrawal action through three-order differential action of two gears with different diameters, so as to realize accurate control of the small distance with an accuracy of 0.01 mm.

[0034] The T-shaped plate 4 includes a flat plate and a vertical plate. The lower end of the vertical plate is connected to the middle part of the flat plate to form an inverted T-shaped structure. The holes distributed on the four corners of the flat plate are used to connect with the output end table of the XY axis fine adjustment platform 3 through bolts. The six holes distributed on the vertical plate are used to connect with the vertical displacement mechanism 5 through bolts.

[0035] The vertical displacement mechanism 5 is connected with the six holes distributed on the upper part of the vertical connecting plate 6 through bolts. The four holes distributed on the lower part of the vertical connecting plate 6 are used to connect with the drill sleeve 7 through bolts.

[0036] The drill sleeve 7 is used to fix the magnifying glass or the drilling motor.

[0037] The vertical displacement mechanism 5 is composed of a stepping motor and a vertical cylinder. The stepping motor controls the vertical movement of the piston rod through the internal toothed belt and pulley. The braking mechanism in the motor controls the vertical cylinder to keep the position unchanged after moving to a certain position. The vertical cylinder is composed of a cylinder body and a piston rod. The cylinder body is fixed with a passive sliding block, and the piston rod contains a driven guide rail vertical plane. The driven guide rail vertical plane moves vertically along the passive sliding block by controlling the stepping motor. The moving stroke of the piston rod in the cylinder body is 30 mm, and the accuracy is 0.002 mm.

[0038] The model of the vertical displacement mechanism 5 is ELCSS16L-B2.5-30-S.

[0039] The model of the XY axis fine adjustment platform 3 is LBY60-L-H.

[0040] The external dimensions of the magnetic base 1 are 120mm*55mm*50mm.

[0041] A method for using a drilling device for detecting residual stress in a machine tool bed includes the following steps:

[0042] Step 1: Surface treatment of the machine tool bed under test: First, observe the surface condition of the machine tool bed under test. Attach strain gauges to the drilling points on the machine tool bed under test. Electrically connect the strain gauges to the strain gauges, ensuring that the strain gauges are firmly attached and free of air bubbles. Ensure that the surface on the machine tool bed under test on which the drilling device is placed is flat, smooth, and free of impurities, thus providing favorable conditions for a strong magnetic connection between the magnetic base 1 and the machine tool bed under test. At the same time, ensure that the drill sleeve 7 is perpendicular to the surface of the machine tool bed under test.

[0043] Step 2: Fix the automatic drilling device: Place the drilling device on the surface of the machine tool bed material, observe the center of the strain gauge through the drill sleeve 7, initially align the center of the drill sleeve 7 with the center of the strain gauge, rotate the switch knob on the magnetic base 1 counterclockwise to point the switch knob to the + position, and ensure that the magnetic base 1 is firmly connected to the machine tool bed under test.

[0044] Step 3: Adjust vertical displacement: Place a high-magnification magnifying glass inside the drill sleeve 7, and adjust the distance between the high-magnification magnifying glass and the strain gauge by controlling the stepper motor of the vertical displacement mechanism 5, until the strain gauge can be clearly observed in the high-magnification magnifying glass.

[0045] Step 4: Adjust the horizontal displacement: Adjust the two differential heads of the XY axis fine adjustment platform 3 in sequence so that the center of the crosshairs of the high magnification lens is completely aligned with the center of the strain gauge. Then, use the opposing clamping mechanism and the friction locking mechanism of the XY axis fine adjustment platform 3 to double lock the XY axis fine adjustment platform 3 to ensure that the drill sleeve 7 and the strain gauge have accurate and stable concentricity during drilling.

[0046] Step 5, Drilling: Remove the high-magnification magnifying glass from the drill sleeve 7, insert the drilling motor with the drill bit into the drill sleeve 7, adjust the speed of the drilling motor to 60000 r / min, control the output end of the vertical displacement mechanism 5 to move downward, so that the drilling end of the drill bit is in contact with the strain gauge, then set the operating parameters of the stepper motor of the vertical displacement mechanism 5, set the drilling depth to 2mm, divide the hole depth into 8 layers, each layer with a depth of 0.25mm, so that the output end of the vertical displacement mechanism 5 descends at a rate of one layer per minute, pause for 1 minute between two layers of drilling, so that the strain gauge can collect the displacement or strain of the strain gauge, the total time is 15 minutes;

[0047] Step six, remove the automatic drilling device: after obtaining the data collected by the strain gauge, the output end of the vertical displacement mechanism 5 is controlled to move upward, ensuring that the drill bit of the drilling motor leaves the measured machine tool bed, the speed of the drilling motor is adjusted to 0r / min, the drilling motor is removed from the drill sleeve 7, the switch knob on the magnetic base 1 is rotated clockwise, the switch knob is pointed to the - block, the magnetic base 1 is separated from the measured machine tool bed, and the next to-be-measured point is prepared to be drilled.

[0048] The advantages of the utility model are as follows:

[0049] 1, the larger size magnetic base 1 of internal permanent magnet is selected, so that the adsorption force generated by the magnetic base 1 can reach 1500N, which is used for the automatic drilling device of the utility model, so that the drilling device of the utility model is combined with the measured machine tool bed more firmly.

[0050] 2, the transmission member adopted by the X-Y gear rack horizontal displacement platform in the traditional magnetic base is gear and rack, which is suitable for rapid adjustment and is not suitable for precise positioning, and the accuracy is 0.1mm. The transmission member adopted by the XY axis fine adjustment platform 3 in the utility model is a differential head, which is suitable for precise adjustment with 0.01mm unit. Therefore, the horizontal displacement adjustment accuracy of the drilling device of the utility model is improved by 10 times, and the adjustment accuracy is higher.

[0051] 3, the traditional magnetic base drill frame is matched with a drill rod and a low-speed electric drill, and a 2mm deep hole is drilled by manual operation, and the manual operation error is large; the automatic drilling device of the utility model adopts the vertical displacement mechanism 5 matched with a high-speed drilling motor to drill, and the drilling motor can provide stable drilling driving force by relying on its own weight, reducing the manual operation error. At the same time, the traditional magnetic base drill frame cannot realize layer-by-layer drilling, and can only drill a 2mm deep hole for stress measurement at a time, and the minimum feed amount of the vertical displacement mechanism 5 in the automatic drilling device of the utility model is 0.002mm, which meets the required 0.25mm feed depth of each layer for conventional layer-by-layer drilling, so that the comprehensive stress error obtained by subsequent calculation is smaller.

[0052] The above embodiments are only exemplary descriptions of the utility model, and do not limit the protection scope thereof, and the skilled in the art can also change part of it, as long as it does not exceed the spirit and essence of the utility model, and is within the protection scope of the utility model.

Claims

1. A drilling device for residual stress detection of a machine tool bed body, characterized by: The utility model relates to a magnetic base (1), plane connecting plate (2), XY axis fine adjustment platform (3), T-shaped plate (4), vertical displacement mechanism (5), vertical connecting plate (6) and drill sleeve (7) are included, plane connecting plate (2) sets up on magnetic base (1), XY axis fine adjustment platform (3) sets up on plane connecting plate (2), T-shaped plate (4) is connected with the output end of XY axis fine adjustment platform (3), vertical displacement mechanism (5) sets up on T-shaped plate (4), vertical connecting plate (6) is connected with the output end of vertical displacement mechanism (5), drill sleeve (7) is connected with vertical connecting plate (6), and drill sleeve (7) is equipped with the positioning hole that goes through up and down.

2. The drilling device for residual stress detection of machine tool bed according to claim 1, characterized in that: The vertical displacement mechanism (5) is composed of a stepping motor and a vertical electric cylinder.

3. The drilling device for residual stress detection of machine tool bed according to claim 2, characterized in that: The model of the vertical displacement mechanism (5) is ELCSS16L-B2.5-30-S.

4. The drilling device for residual stress detection of machine tool bed according to claim 3, characterized in that: The model of the XY axis fine adjustment platform (3) is LBY60-L-H.

5. The drilling device for residual stress detection of machine tool bed according to claim 3, characterized in that: The outer dimensions of the magnetic base (1) are 120mm*55mm*50mm.

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