CN109738468B - A Universal Probe Holder for Sample Positioning in Neutron Diffraction Measurements - Google Patents

Abstract

The invention provides a universal probe clamping device for sample positioning in neutron diffraction measurement, which comprises a clamping mechanism and a lifting mechanism, wherein the lifting mechanism comprises a top plate, a lifting table and a base which are sequentially arranged from top to bottom, a supporting guide rail for connecting the top plate and the base, and a lifting rod which is in linkage with the lifting table through threaded fit, and the lifting table can be driven to move up and down along the supporting guide rail by rotating the lifting rod; the clamping mechanism comprises two clamping components positioned on the base and the lifting platform, each clamping component comprises a fastener and a guide sleeve, opposite ends of the two fasteners are arranged into a hollow conical structure and are uniformly divided into a plurality of fan-shaped pressing sheets along the circumferential direction, and the guide sleeves are sleeved on the fasteners and fix the probes by forcing the pressing sheets to be inwards close; still including the backup through-hole and the V type groove of symmetry setting on elevating platform and base, its axis is located same vertical face with the fastener axis. The invention can realize high-precision clamping of probes with any diameter in a certain range, is convenient to use and expands the application range.

Description

A Universal Probe Holder for Sample Positioning in Neutron Diffraction Measurements

technical field

The invention relates to the technical field of neutron diffraction residual stress detection, in particular to a probe clamping device, which is applied to sample positioning when using neutron diffraction to measure the residual stress of materials and components, and is suitable for Clamping and fixing of probes of any diameter within a certain range.

Background technique

Residual stress is an important factor affecting the properties of materials and structures such as fatigue strength, structural stiffness, stress corrosion resistance, etc. Therefore, it is important to study the working state and service life of engineering component materials in complex application environments and quantitatively measure the numerical distribution of residual stress. Significance and significant application value.

At present, the methods that can detect the internal residual stress of components are mainly divided into nondestructive testing methods and nondestructive testing methods. Among them, neutron diffraction method is the representative method in nondestructive testing methods, and it is also the most effective nondestructive testing method for residual stress detection so far. Detection method. The neutron diffraction spectrometer is a device that uses the principle of neutron diffraction to measure the residual stress. At present, most of the positioning methods used in the world use the neutron beam scanning edge positioning method: for the regular measured sample with known outline and size, the neutron beam The scanning edge positioning method firstly installs the sample on the sample stage and calibrates the initial position. During measurement, adjust the sample to an appropriate angle and position, control the movement of the sample, and start the measurement from the surface boundary contour to obtain diffracted neutrons. Beam intensity, gradually translate the sampling volume into the interior of the sample, record the outgoing intensity of each neutron beam diffraction, until the sampling volume is gradually removed from the outer boundary, from the "in-exit" measurement process between the two boundaries of the sample thickness. A neutron beam peak intensity profile is produced, called the "entry curve". The jump position interval on both sides of the curve is the sample thickness, and the position corresponding to half of the curve height is the position where the sample boundary moves to the diffraction point. Then, the position and posture of the geometric center of the sample in the measurement space are determined according to the profile geometric information of the sample and the installation position known in advance.

This edge-sweeping positioning method requires the sample to be tested to have a regular and known contour or a specific surface shape, and to scan the surface multiple times to obtain the correct "entry curve", which requires long positioning time and low accuracy. However, in the actual measurement process, the shape of the sample is indeterminate and varied, and when the scanned surface has texture, large grains or high absorption materials, the incident curve will be deformed, which cannot achieve accurate positioning. .

In order to overcome the above shortcomings, a sample positioning method based on a standard probe is proposed. The relative positional relationship of the sample realizes the positioning of the measurement point in the sample, and finally completes the measurement of the residual stress in the sample.

Because probes of different diameters and materials are required in different experimental environments, probes are frequently replaced. The current probe clamping device is generally one-piece clamping, and the aperture size of the clamping part cannot be adjusted. In the limited operating space, not only is the probe replacement more troublesome, but also because the probe itself has a large length and diameter and is not adjustable. One end is fixed and the other end is suspended, which is prone to deformation and breakage. The above situation will seriously affect the progress of the experiment, waste precious neutron beam time, and cause huge economic losses in the long run. At the same time, in the probe-based sample positioning method, the installation accuracy and verticality of the probe must be guaranteed at all times, which puts forward higher requirements on the structural design of the probe clamping device.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a probe clamping device with convenient clamping, high installation accuracy and suitable for probes of any diameter, so as to solve the problems raised in the background art.

In order to achieve the above object, the present invention provides a universal probe clamping device for sample positioning in neutron diffraction measurement, including a clamping mechanism for fixing the probe and a tensioning mechanism for realizing the probe. straight lift mechanism;

The clamping mechanism includes two upper and lower opposite clamping assemblies, the distance between the two clamping assemblies in the vertical direction can be adjusted through the lifting mechanism, and the clamping assembly includes a fastener and a guide sleeve. The opposite ends of the fasteners are arranged in a tapered structure and are hollow inside for inserting the end portion of the probe. The opposite ends of the fasteners are circumferentially divided into a plurality of fan-shaped pressing pieces of equal shape and size, so The guide sleeve is sleeved on the opposite end of the fastener, and the inner cavity of the guide sleeve is set to a conical structure matching the fastener, and the guide sleeve produces radial extrusion on the pressing piece of the fastener, forcing the All the pressing pieces move toward the middle at the same time, so as to realize the clamping and fixing of the inserted probe in the middle.

Preferably, the lifting mechanism includes a top plate, a lifting platform and a base arranged in sequence from top to bottom, and a support rail and a lifting rod vertically arranged on the base, and the lower end of the support connecting rail is fixedly connected to the base The upper end passes through the lifting platform and is fixedly connected with the top plate, the lower end of the lifting rod and the base are rotatably connected or clearance fit, and the upper end passes through the lifting platform and the top plate, and the lifting rod is rotatably connected with the base. The rod and the lifting platform are arranged in a threaded linkage, and the force is transmitted to the lifting platform along the thread by rotating the lifting rod to drive the lifting platform to move up and down along the support guide rail; two clamping assemblies are respectively arranged on the lifting platform and the base.

Preferably, in order to ensure that the lifting platform can have good position-limiting ability and positioning accuracy at any height, the transmission part between the lifting rod and the lifting platform selects the thread with the thread lift angle smaller than the equivalent friction angle of the screw pair, so that the The two have a good self-locking effect.

Preferably, a spare through hole is also included, and the spare through hole is symmetrically arranged on the lifting platform and the base and is used for long-term clamping and positioning of both ends of the probe.

Preferably, there are multiple sets of spare through holes with different diameters, and the central axis of each set of spare through holes and the central axis of the fastener are located on the same vertical plane.

Preferably, it also includes a set of V-shaped grooves for clamping and positioning probes of any diameter, the V-shaped grooves are symmetrically arranged on the lifting platform and the base, and the central axis of the V-shaped grooves is the same as the spare The central axis of the through hole and the central axis of the fastener are located on the same vertical plane.

For the probe clamped by the spare through hole or V-groove, the two ends of the probe can be wrapped around the fixing bolt and fixed by the fixing bolt, or the spare through-hole or V-groove can be used to fix the probe. It is fixed by inserting bolts in the middle to fix the position of the probe and tighten it.

Preferably, the clamping assembly further includes a base, the base is fixed on the lifting platform and the base by fixing bolts, and a slot for the fastener to be inserted and fixed is provided on the base. , there is clearance fit between the fastener and the card slot.

Preferably, the clamping assembly further comprises a set bolt for preventing the circumferential rotation of the base, the set bolt is horizontally arranged on the lifting platform and the base and presses the base from the side fixed.

Preferably, the two set bolts are located on the same side of the base.

Preferably, the upper end of the lift rod is provided with a handle which is convenient for applying force.

Preferably, matching threads are provided on the inner side wall of the guide sleeve and the outer side wall of the fastener or the base, and the pressing sheet can be loosened by rotating the guide sleeve to make it approach or move away from the fastener. and oppression.

In order to ensure the reliability, wear resistance, bending resistance and corrosion resistance of the device itself, the material of each component of the present invention is selected from stainless steel or high performance with good performance in strength, wear resistance, oxidation resistance and corrosion resistance. Aluminum alloy.

The technical solution provided by the invention has at least the following beneficial effects:

1. The present invention has good practicability. By setting a freely movable lifting platform, the probe can be tightened and straightened, and the length of the clamped probe can be flexibly adjusted according to the actual situation. The fasteners and the threaded guide sleeve can be used to quickly replace the probe, which is not only flexible in operation, but also can ensure the center axis of the clamped probe and the center of the clamping assembly. The shafts are completely coincident to avoid the eccentricity of the probe, thereby ensuring the installation accuracy of the probe.

2. The present invention realizes the clamping and fixing of probes that do not need to be replaced for a long time by setting multiple groups of spare through holes, which simplifies the experimental process and enables accurate positioning. The number of spare through holes and the spare groups of each group can also be specifically designed according to actual needs. The diameter of the through hole has good applicability.

3. The present invention further expands the application range of the probe holding device by setting the V-shaped groove, which not only completely gets rid of the device’s use restriction on the probe diameter, but also provides a large enough operating space to ensure the quick action when replacing the probe. It is flexible and avoids damage to the probe caused by bumping; because the V-shaped groove has good positioning and centering ability for the probe with a cylindrical shape, it can ensure the installation accuracy of the probe.

4. The present invention shortens the experimental period while ensuring the installation accuracy of the probe, greatly reduces the time consumed by the sample positioning experimental scheme, is beneficial to the precise positioning of the sample to be tested, saves precious neutron beam time, and improves positioning. Measure the efficiency and save cost loss.

5. The invention arranges the upper and lower fixing bolts on the same side of the base, so that the upper and lower ends of the probe receive the force from the same direction at the same time, so as to ensure that the probe always maintains the verticality relative to the base and improve the sample's stability. positioning accuracy.

Description of drawings

In order to illustrate the technical solutions of the present invention more clearly, the following will briefly introduce the drawings used in the description of the embodiments of the present invention. Obviously, the following drawings are only used to help understand some embodiments of the present invention, rather than All of the technical solutions, including:

1 is a schematic perspective view of Embodiment 1 of the present invention;

Fig. 2 is the structural representation of the front view of Fig. 1;

Fig. 3 is the structural representation of the left side view of Fig. 1;

Fig. 4 is the enlarged schematic diagram of the part circled in Fig. 3;

5 is a working schematic diagram of the probe clamping device in Example 1 when it is used in a sample positioning experiment;

Among them: 01 probe, 02 sample stage, 03 incident slit, 04 neutron detector, 05 incident neutron beam, 06 diffracted neutron beam, 021 load pallet, 022X axis drive servo motor, 023Y axis drive servo motor, 024Z-axis first-stage lifting cylinder, 025Z-axis second-stage lifting cylinder, 026Z-axis rotating mechanism; 1 top plate, 2 lifting table, 3 base, 31 bolt connection holes, 4 supporting rails, 5 lifting rods, 6 handles, 7 clamping Assembly, 71 Base, 72 Fasteners, 73 Guide Bushes, 74 Set Bolts, 75 Set Bolts, 8 Spare Through Holes, 9 V-Slots.

Detailed ways

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. Obviously, the described embodiments are only some of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

Example 1

Referring to FIGS. 1 to 4 , a universal probe clamping device for sample positioning in neutron diffraction measurement, including a clamping mechanism for fixing the probe 01 and a clamping mechanism for realizing the probe 01 taut and stretched Straight lift mechanism.

The lifting mechanism includes a top plate 1 , a lifting platform 2 , a base 3 , a supporting guide rail 4 , a lifting rod 5 and a handle 6 . The top plate 1 , the lifting platform 2 and the base 3 are arranged in order from top to bottom, the base 3 is provided with a bolt connection hole 31 for realizing its connection with the sample stage, and the supporting rail 4 vertically passes through the lifting and lowering. The table 2 and its upper and lower ends are respectively fixed with the top plate 1 and the base 3, the lifting rod 5 is also vertically arranged and located between the two support rails 4, and the base 3 is provided with a lifting rod for accommodating the lifting rod 5. The groove at the lower end, the upper part of the lifting rod 5 passes through the lifting platform 2 and the top plate 1, and a handle 6 is provided on the upper end of the lifting rod 5.

Wherein, between the support rail 4 and the lifting platform 2, between the lifting rod 5 and the groove of the base 3, and between the lifting rod 5 and the top plate 1 are clearance fit, the lifting rod 5 and the lifting platform are all clearance fit. The linkage between the 2 is realized by threaded cooperation; by rotating the lifting rod, the force is transmitted to the lifting platform along the thread, so as to drive the lifting platform to move up and down along the supporting guide rail.

In the present embodiment, the transmission part between the lift rod 5 and the lift table 2 is matched with a thread whose thread lift angle is smaller than the equivalent friction angle of the screw pair, so that the two have a good self-locking effect and ensure that the lift table 2 positioning accuracy.

The clamping mechanism includes two upper and lower coaxially opposite clamping assemblies 7 respectively disposed on the lifting platform 2 and the base 3 . The clamping assemblies 7 include a base 71 , a fastener 72 and a guide sleeve 73 . , the base 71 is fixedly connected with the lifting platform 2 and the base 3 through the vertically arranged fixing bolts 75, and the base 71 is provided with a slot for realizing the insertion and fixing of the fastener 72, and the fastener There is a clearance fit between 72 and the slot, the opposite ends of the two fasteners 72 are arranged in a conical structure and the inside is hollow for inserting the end portion of the probe 01, and the opposite ends of the fasteners 72 are uniform in the circumferential direction. Divided into a plurality of equal sector-shaped pressing pieces, the guide sleeve 73 is sleeved on the opposite end of the fastener 72 and the inside of the guide sleeve 73 is set as a conical cavity matching the shape of the fastener 72. The inner side wall of the guide sleeve 73 and the outer side wall of the base 71 are provided with matching threads; by rotating the guide sleeve to make it approach or away from the fastener, the relaxation and compression of the pressing sheet can be realized. Press the tab and force it to move toward the middle to clamp and fix the probe inserted in the middle.

Since the fastener 72 and the base 71 are connected in an extremely easy-to-remove manner, in actual use, fasteners with different opening diameter ranges can be replaced according to the diameter of the probe used.

The clamping assembly 7 further includes a fixing bolt 74, which is inserted into the lifting platform 2 and the base 3 horizontally and presses and fixes the base 71 from the side, so as to prevent the base from rotating in the circumferential direction.

In this embodiment, two set bolts 74 are located on the same side of the base 71 to ensure the verticality of the probe.

The device also includes two sets of spare through holes 8 with different diameters and a set of V-shaped grooves 9 . Each group of spare through holes are symmetrically arranged on the lift table 2 and the base 3 and used to achieve long-term clamping and positioning of both ends of the probe. The V-shaped grooves 9 are symmetrically arranged on the lift table 2 and the base 3 and are used to achieve any For the clamping and positioning of the diameter probe, the central axis of the V-shaped groove 9 is located on the same vertical plane as the central axis of each group of spare through holes 8 and the central axis of the fastener 72 . When fixing both ends of the probe, an appropriate fixing method can be selected according to the diameter and material of the probe.

With reference to Fig. 5, the experimental conditions for neutron diffraction measurement include the sample stage 02 of the neutron diffraction spectrometer, the incident slit 03, the neutron detector 04, the neutron beam baffle, the shielding drum and the total station measurement system (Fig. not all shown). The measurement method is a probe-based sample positioning method.

The process of neutron diffraction measurement is as follows:

1. Assemble the probe clamping device and set the midpoint of the probe as the mark point, and fix the entire probe clamping device on the load support plate 021 of the sample stage 02 through the cooperation of the hexagon socket head bolt and the bolt connection hole 31. At the same time, the sample to be measured for residual stress is also fixed on the load support plate 021, and the relative position of any point on the sample and the marked point is a fixed value at this time;

2. The incident neutron beam 05 is emitted through the incident slit 03, and the diffracted neutron beam 06 is received through the neutron detector 04;

3. Drive the load pallet 021 to move in the X-axis, Y-axis and Z-axis directions or rotate around the Z-axis through the X-axis drive servo motor 022, the Y-axis drive servo motor 023, two Z-axis lift cylinders and the Z-axis rotation mechanism 26 , take the marked point as the reference point for diffraction measurement, use the neutron beam sweep method to determine the center pose of the sampling volume, and move the marked point on the probe to the intersection of the incident neutron beam 05 and the diffracted neutron beam 06, the diffraction point;

4. Use the total station measurement system to calibrate the coordinate system of the sample stage, etc., and calculate that the point on the sample to be measured for residual stress (ie the point to be measured) and the midpoint of the probe (ie the marker point) are in the sample stage coordinate system relative pose;

5. Drive the sample stage 02 to move and the movement amount is the calculated relative pose size, and move the point to be measured on the sample to the diffraction point for residual stress measurement;

6. The wavelength change of the diffracted neutron beam 06 is analyzed by the neutron detector 04, and the residual stress at the point to be measured on the sample is calculated by the Bragg principle.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the scope of patent protection of the present invention. For those skilled in the art, the present invention may have various modifications and changes. Within the spirit and principle of the present invention, any improvement or equivalent replacement made by using the contents of the description and drawings of the present invention, directly or indirectly applied in other related technical fields, shall be included in the scope of patent protection of the present invention.

Claims (10)

1. A universal probe clamping device for sample positioning in neutron diffraction measurement, characterized in that it comprises a clamping mechanism for fixing a probe (01) and a clamping mechanism for realizing the probe (01) Tight and straight lifting mechanism; The clamping mechanism includes two upper and lower opposite clamping assemblies (7), the distance between the two clamping assemblies in the vertical direction can be adjusted through the lifting mechanism, and the clamping assembly (7) includes a fastening A piece (72) and a guide sleeve (73), the opposite ends of the two fasteners (72) are arranged in a tapered structure and are hollow inside for inserting the tip portion of the probe (01), the fasteners (72) ) is divided into a plurality of fan-shaped pressing pieces of equal shape and size along the circumferential direction, the guide sleeve (73) is sleeved on the opposite end of the fastener (72) and the inside of the guide sleeve (73) The cavity is arranged in a conical structure matching the fastener (72), and the pressing pieces of the fastener are radially compressed by the guide sleeve, forcing all the pressing pieces to move toward the middle at the same time, so as to realize the insertion of the probe in the middle. Clamped and fixed. 2. The universal probe clamping device for sample positioning in neutron diffraction measurement according to claim 1, wherein the lifting mechanism comprises a top plate (1), a lifting platform ( 2) and the base (3), as well as the support guide rail (4) and the lifting rod (5) vertically arranged on the base (3), the lower end of the support connecting guide rail (4) is fixed to the base (3) The upper end passes through the lifting platform (2) and is fixedly connected with the top plate (1). Passing through the lifting platform (2) and the top plate (1), and the lifting rod (5) and the lifting platform (2) are arranged in a coordinated manner through the screw thread, and the force is transmitted to the lifting platform along the thread by rotating the lifting rod to drive the lifting platform. The lifting platform moves up and down along the support guide rail; two clamping assemblies are respectively arranged on the lifting platform (2) and the base (3). 3. The universal probe clamping device for sample positioning in neutron diffraction measurement according to claim 2, characterized in that it further comprises a spare through hole (8), and the spare through hole is symmetrically arranged in the lift The platform (2) and the base (3) are used to realize permanent clamping and positioning of both ends of the probe (01). 4. The universal probe holding device used for sample positioning in neutron diffraction measurement according to claim 3, wherein the number of the spare through holes (8) is multiple groups and has different diameters, and each group has different diameters. The central axis of the spare through hole and the central axis of the fastener (72) are located on the same vertical plane. 5. The universal probe clamping device for sample positioning in neutron diffraction measurement according to claim 3, characterized in that it further comprises a set of V clamps for realizing (01) clamping and positioning of probes of any diameter A groove (9), the V-shaped groove (9) is symmetrically arranged on the lifting platform (2) and the base (3), and the central axis of the V-shaped groove (9) and the spare through hole (8) The central axis of the fastener and the central axis of the fastener (72) are located on the same vertical plane. 6. The universal probe clamping device for sample positioning in neutron diffraction measurement according to claim 5, wherein the clamping assembly (7) further comprises a base (71), the base (71) is fixedly arranged on the lifting platform (2) and the base (3) through fixing bolts (75), and the base (71) is provided with a fixing bolt (72) for inserting and fixing the fastener (72). A clamping slot, the fastener (72) and the clamping slot are in clearance fit. 7. The universal probe clamping device for sample positioning in neutron diffraction measurement according to claim 6, wherein the clamping assembly (7) further comprises a base (71) for preventing the A set bolt (74) that rotates in the circumferential direction, the set bolt (74) is horizontally arranged on the lifting platform (2) and the base (3), and the base is pressed and fixed from the side. 8. The universal probe holding device for sample positioning in neutron diffraction measurement according to claim 7, characterized in that two fixing bolts (74) are located on the same side of the base (71). 9. The universal probe clamping device for sample positioning in neutron diffraction measurement according to any one of claims 2 to 8, characterized in that, an upper end of the lifting rod (5) is provided with a convenient tool for applying Power handle (6). 10. The universal probe holding device for sample positioning in neutron diffraction measurement according to claim 9, characterized in that, in the inner wall of the guide sleeve (73) and the fastener (72) Or the outer side wall of the base (71) is provided with matching threads, and by rotating the guide sleeve to make it approach or move away from the fastener, so as to realize the relaxation and compression of the pressing sheet.

Images