Linear expansion coefficient determination experimental instrument based on Hall effect

Abstract

The utility model discloses a linear expansion coefficient measurement experimental instrument based on a Hall effect. The linear expansion coefficient measurement experimental instrument comprises a supporting seat and a heating cylinder, a heating wire is arranged in the inner wall of the heating cylinder, the heating cylinder is horizontally supported and fixed through a supporting base, an induction support is arranged beside the supporting base, a main body of the induction support is two sets of supporting plates of a vertical plate-shaped structure, the two supporting plates are vertically fixed through a rod piece, and an aluminum magnetic field box of a metal box-shaped structure with an upper opening is fixedly connected between the two sets of supporting plates. The inner walls of the left side and the right side of the aluminum magnetic field box are each fixedly provided with a magnetic plate in an attached mode, the two sets of magnetic plates are parallel to each other, a sensing fixing frame is arranged above the magnetic field box, a Hall sensor is fixed to the sensing fixing frame, and a horizontal horizontally-arranged rod is fixed to the side, away from the supporting base, of the sensing fixing frame. The other side of the sensing fixing frame is provided with a rod fixing device used for fixing a to-be-detected metal rod. The two sets of supporting plates of the sensing support are provided with penetrating holes for the to-be-detected metal rod and the horizontal rod to slide to form rod penetrating holes. The beneficial effect is that the measurement precision is high.

Description

Technical Field

[0001] The utility model belongs to the technical field of linear expansion coefficient measurement, and particularly relates to a linear expansion coefficient measurement experimental instrument based on the Hall effect. Background Art

[0002] The linear expansion of a material is the elongation in one dimension when the material expands due to heat. The linear expansion coefficient is an important indicator for selecting materials, especially for developing new materials. The linear expansion coefficient of the material must be measured. Traditional linear expansion coefficient measurements mostly use micrometers and optical lever scales to measure the deformation of the material to be tested, and the readings are all observed by the naked eye (such as the metal linear expansion coefficient meter with publication number CN218067724U). There are defects such as large influence of human factors, inconvenient readings, and large measurement errors. Utility Model Content

[0003] The utility model aims to provide a linear expansion coefficient measuring test instrument based on the Hall effect, so as to solve the problems of large influence of human factors, inconvenient reading and large measurement error in the above-mentioned background technology.

[0004] The above technical objectives of the utility model are achieved through the following technical solutions:

[0005] A linear expansion coefficient determination test instrument based on the Hall effect comprises: a support base and a heating tube; the heating tube is a cylindrical structure with a heating wire built into its inner wall, the heating tube is horizontally supported and fixed by the support base, an induction bracket is arranged beside the support base, the main body of the induction bracket is two groups of support plates with vertical plate-like structures, the two support plates are vertically fixed by rods, an aluminum magnetic field box with an upper open metal box-like structure is connected and fixed between the two groups of support plates, a magnetic plate is attached and fixed to the inner walls of the left and right sides of the aluminum magnetic field box respectively, the two groups of magnetic plates are parallel to each other, a sensor fixing frame is arranged above the magnetic field box, a Hall sensor is fixed on the sensor fixing frame, a horizontal flat rod is fixed on one side of the sensor fixing frame away from the support base, a rod fixing device for fixing a metal rod to be measured is arranged on the other side of the sensor fixing frame, and the two groups of support plates of the induction bracket are provided with through holes for sliding of the metal rod to be measured and the flat rod to form a through rod hole.

[0006] Furthermore, in order to facilitate the translation of the metal rod to be tested and the horizontal rod, a rolling assembly is provided under the rod through hole of the sensing bracket, and the rolling assembly includes: a connecting plate, a wheel frame, a rotating shaft, a first bearing, a rotating wheel, and a wheel sleeve; the connecting plate is a plate-like structure, and the connecting plate is directly or indirectly fixed to the support plate on the same side thereof, and a wheel frame of a plate-like structure is provided on each side of the connecting plate, and a rotating shaft is provided on the top of each group of wheel frames, and there are two groups of rotating shafts in total, and the two groups of rotating shafts are concentrically arranged, and a rotating wheel is rotatably fitted on each group of rotating shafts by means of the first bearing, and a wheel sleeve is externally embedded on the two groups of rotating wheels.

[0007] Furthermore, in order to prevent the heat on the metal rod to be tested from being lost through the wheel sleeve, the wheel sleeve is made of a material with low thermal conductivity.

[0008] Furthermore, in order to compensate for the height difference formed by the metal rods to be tested with different diameters, the connecting plate is matched with the support plate through a leveling assembly, and the leveling assembly includes: a fixed plate, an upper support rod, a lower support rod, a sliding rod, a screw rod, a rotating handle, and a second bearing; the fixed plate is a vertical plate-like structure, and the fixed plate is fixed to the side wall of the support plate. Two groups of outwardly extending crossbeam supports are respectively provided on the upper and lower parts of the support plate to form an upper support rod and a lower support rod. A vertical sliding rod is provided between the upper and lower support rods. The connecting plate is slidably matched on the sliding rod, and a screw rod is threadedly connected to the lower part of the lower support rod. The top of the screw rod forms a rotational fit with the connecting plate through the second bearing.

[0009] Furthermore, in order to facilitate the rotation of the screw rod, a rotating handle perpendicular to the screw rod is connected below the screw rod.

[0010] Furthermore, in order to keep the metal rod to be tested and the sensor fixing frame in a concentric connection, the sensor fixing frame is provided with a three-jaw chuck for fixing the metal rod to be tested, and the clamping center of the three-jaw chuck is coaxial with the flat rod.

[0011] Furthermore, in order to avoid the Hall sensor from interfering with the measured value, the Hall sensor includes: a sensor body, a mounting tube, and a sensing end, wherein the sensor body is fixed on the sensor fixing frame by the mounting tube, the sensing end of the sensor body is located inside the sensor fixing frame by a wire penetrating the mounting tube, and the sensor fixing frame is made of non-magnetic material.

[0012] Furthermore, in order to avoid unnecessary heat loss and increase the heating rate of the metal rod to be tested, the heating tube is covered with a heat-insulating tube made of a heat-insulating material.

[0013] Furthermore, in order to fix one end of the metal rod to be tested so that it only moves toward one end when it is extended or retracted, the heating tube is threadedly matched with a circumferentially arranged clamping bolts on the side away from the sensing bracket. When all the clamping bolts are locked, the heating tube and the metal rod to be tested can be clamped and fixed.

[0014] In summary, the utility model has the following beneficial effects:

[0015] ① High measurement accuracy: The utility model constructs a uniform gradient magnetic field, utilizes the characteristic that the magnetic field strength in the uniform gradient magnetic field is linearly related to the corresponding position, and uses the deformation caused by the thermal expansion of the material to drive the Hall sensor to move in the uniform gradient magnetic field to characterize the solid linear expansion coefficient, and converts the small deformation amount that is difficult to measure into the change in magnetic field intensity. In this way, the small deformation in the measurement experiment has high measurement accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0017] Figure 2 This is a schematic diagram of the structure of the Hall sensor of the utility model;

[0018] Figure 3 It is a structural schematic diagram of the rolling assembly and the leveling assembly in the utility model;

[0019] Figure 4 yes Figure 1 A magnified view of the structure in the middle;

[0020] In the figure, 1, support seat; 2, heating tube; 3, induction bracket; 4, aluminum magnetic field box; 5, magnetic plate; 6, sensor fixing frame; 7, Hall sensor; 8, rolling assembly; 9, leveling assembly; 10, insulation tube; 11, flat rod; 12, metal rod to be measured; 21, clamping bolt; 31, support plate; 32, rod hole; 61, three-jaw chuck; 71, sensor body; 72, mounting tube; 73, induction end; 81, connecting plate; 82, wheel frame; 83, rotating shaft; 84, first bearing; 85, rotating wheel; 86, wheel sleeve; 91, fixing plate; 92, upper support rod; 93, lower support rod; 94, sliding rod; 95, screw rod; 96, rotating handle; 97, second bearing. DETAILED DESCRIPTION

[0021] The utility model is further described in detail below in conjunction with the accompanying drawings.

[0022] Example:

[0023] See also Figure 1-Figure 4 , the utility model provides a technical solution:

[0024] A linear expansion coefficient determination experimental instrument based on Hall effect, comprising: a support base 1, a heating tube 2; the heating tube 2 is a cylindrical structure, and a heating wire is built into its inner wall. The heating tube 2 is horizontally supported and fixed by the support base 1, and a sensing bracket 3 is arranged beside the support base 1. The main body of the sensing bracket 3 is two groups of support plates 31 of vertical plate-like structure, and the two support plates 31 are vertically fixed by a rod. An aluminum magnetic field box 4 with an upper open metal box-like structure is connected and fixed between the two groups of support plates 31, and a magnetic plate 5 is attached and fixed to the inner walls of the left and right sides of the aluminum magnetic field box 4 respectively, and the two groups of magnetic plates 5 are parallel to each other. A sensing fixing frame 6 is arranged above the magnetic field box 4, and a Hall sensor 7 is fixed on the sensing fixing frame 6. A horizontal horizontal rod 11 is fixed on the side of the sensing fixing frame 6 away from the support base 1, and a rod fixture for fixing a metal rod 12 to be measured is arranged on the other side of the sensing fixing frame 6. The two groups of support plates 31 of the sensing bracket 3 are provided with perforations for the metal rod 12 to be measured and the horizontal rod 11 to slide to form a rod hole 32.

[0025] In order to facilitate the translation of the metal rod 12 to be tested and the horizontal rod 11, a rolling assembly 8 is provided under the rod hole 32 of the sensing bracket 3, and the rolling assembly 8 includes: a connecting plate 81, a wheel frame 82, a rotating shaft 83, a first bearing 84, a rotating wheel 85, and a wheel sleeve 86; the connecting plate 81 is a plate-like structure, and the connecting plate 81 is directly or indirectly fixed on the support plate 31 on the same side thereof, and a wheel frame 82 of a plate-like structure is provided on both sides of the connecting plate 81, and a rotating shaft 83 is provided on the top of each group of wheel frames 82, and there are two groups of rotating shafts 83 in total, and the two groups of rotating shafts 83 are concentrically arranged, and a rotating wheel 85 is rotatably fitted on each group of rotating shafts 83 by means of the first bearing 84, and a wheel sleeve 86 is externally embedded on the two groups of rotating wheels 85.

[0026] In order to prevent the heat on the metal rod 12 to be tested from being lost through the wheel sleeve 86, the wheel sleeve 86 is made of a material with low thermal conductivity.

[0027] In order to compensate for the height difference formed by the metal rods 12 to be measured with different diameters, the connecting plate 81 cooperates with the support plate 31 through the leveling component 9, and the leveling component 9 includes: a fixed plate 91, an upper support rod 92, a lower support rod 93, a sliding rod 94, a screw 95, a rotating handle 96, and a second bearing 97; the fixed plate 91 is a vertical plate-like structure, and the fixed plate 91 is fixed to the side wall of the support plate 31. Two groups of outwardly extending crossbeam supports are respectively provided above and below the support plate 31 to form an upper support rod 92 and a lower support rod 93. A vertical sliding rod is provided between the upper support rod 92 and the lower support rod 93. The connecting plate 81 is slidably fitted on the sliding rod 94, and a screw 95 is threadedly connected to the lower side of the lower support rod 93. The top of the screw 95 forms a rotational fit with the connecting plate 81 through the second bearing 97.

[0028] In order to facilitate the rotation of the screw rod 95 , a rotating handle 96 perpendicular to the screw rod 95 is connected below the screw rod 95 .

[0029] In order to keep the metal rod 12 to be tested and the sensor fixing frame 6 connected concentrically, the sensor fixing frame 6 is provided with a three-jaw chuck 61 for fixing the metal rod 12 to be tested, and the clamping center of the three-jaw chuck 61 is coaxial with the flat rod 11.

[0030] In order to prevent the Hall sensor 7 from interfering with the measured value, the Hall sensor 7 includes: a sensor body 71, a mounting tube 72, and a sensing end 73, wherein the sensor body 71 is fixed to the sensor fixing frame 6 by the mounting tube 72, and the sensing end 73 of the sensor body 71 is located inside the sensor fixing frame 6 by a wire penetrating the mounting tube 72, and the sensor fixing frame 6 is made of non-magnetic material.

[0031] In order to avoid unnecessary heat loss and increase the heating rate of the metal rod 12 to be tested, the heating tube 2 is covered with a heat-insulating tube 10 made of heat-insulating material.

[0032] In order to fix one end of the metal rod 12 to be measured so that it only moves toward one end when it is extended or retracted, the side of the heating tube 2 away from the sensing bracket 3 is threadedly equipped with a circumferentially arranged clamping bolts 21. When all the clamping bolts are locked, the heating tube 2 and the metal rod 12 to be measured can be clamped and fixed.

[0033] Brief description of the usage process:

[0034] When in use, the metal rod 12 to be tested is first placed inside the heating tube 2, and the metal rod 12 to be tested is not fixed temporarily. Then, the end of the metal rod 12 to be tested close to the three-jaw chuck 61 is kept concentrically fixed by the three-jaw chuck 61 and the flat rod 11. The flat rod 11 and the metal rod 12 to be tested are both placed on the wheel sleeve 86 of the rolling assembly 8 on the same side thereof, and then all the clamping bolts 21 are locked to complete the single-end fixation of the metal rod 12 to be tested.

[0035] At this time, a thermometer is used to measure the temperature of the metal rod 12 to be measured, which is defined as t1; then the electric heating wire in the heating tube 2 is energized to make it heat up to temperature t2. The heating tube 2 heats the metal rod 12 to be measured to temperature t2. After being heated, the metal rod 12 to be measured expands and contracts. Because one end of the metal rod 12 to be measured is fixed by a clamping bolt 21, the end of the metal rod 12 to be measured that is away from the clamping bolt 21 will expand and contract. Then, the metal rod 12 to be measured will drive the sensing bracket 6 and the sensing end 73 of the Hall sensor 7 to move in the magnetic field formed by the two magnetic plates 5. Because the two magnetic plates 5 are arranged in parallel, the magnetic field between the two magnetic plates 5 is a magnetic field with a uniform gradient. As the sensing end 73 moves in the magnetic field with a uniform gradient, according to the Hall principle, the sensing end 73 will sense a Hall potential difference, and the Hall potential difference will be recorded by the sensor body 71:

[0036] The formula for the change in Hall potential difference is:

[0037]

[0038] In the above formula, K is the Hall sensitivity of the element, ΔZ is the change in the length of the metal material, and I is the current. This formula shows that when the current is constant, if is a constant (the value of each Hall sensor 7 When ΔU H Proportional to ΔZ.

[0039] Therefore, the change in length (△Z) of the metal material when the temperature changes from t1 to t2 can be calculated based on the Hall potential difference recorded by the sensor body 71.

[0040] According to the formula of linear expansion coefficient

[0041] △L=△Z

[0042] In the formula, △L is the change in length of the metal material when the temperature changes from t1 to t2, and in the present invention, it has the same value as △Z. △t is the temperature change, and in the present invention, it is the value of t2-t1. L is the length of the metal material when the temperature is t1, and α is the linear expansion coefficient of the metal.

[0043] The linear expansion coefficient (α) of the metal rod 12 to be tested can be calculated.

[0044] When the metal rod 12 to be tested is extended or retracted, the wheel sleeve 86 provides rolling and sliding. When the diameter of the metal rod 12 to be tested changes, the height of the wheel sleeve 86 of the rolling assembly 8 can be changed by the leveling assembly 9 to adapt it to the diameter of the metal rod 12 to be tested. When adjusting the height of the wheel sleeve 86, the handle 96 is turned, and the handle 96 drives the screw 95 to rotate. Because the screw 95 and the lower support rod 93 are threaded, the screw 95 will rise or fall under the action of rotation. Because the top of the screw 95 and the connecting plate 81 are connected by the second bearing 97 The connecting plate 81 is slidably fitted on the sliding rod 94, so the rising or falling screw rod 95 will drive the connecting plate 81 to follow the rise or rotation, and then the connecting plate 81 drives the rotating wheel 85 and the wheel sleeve 86 indirectly connected to it to rise or fall, so that the wheel sleeve 86 fits the lower surface of the metal rod 12 to be tested to ensure its sliding support (the Hall sensor 7 is a direct application of the utility model, which is not within the protection scope of this application, so its specific working principle is omitted, and its reference model is: QMC5883L).

[0045] This specific embodiment is merely an explanation of the present invention and is not a limitation of the present invention. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A linear expansion coefficient measuring instrument based on the Hall effect, comprising: A support base (1), a heating tube (2), and a rolling assembly (8); characterized in that: the heating tube (2) is a cylindrical structure, the inner wall of which is provided with a heating wire, the heating tube (2) is supported and fixed horizontally by the support base (1), a sensing bracket (3) is provided on the side of the support base (1), the main body of the sensing bracket (3) is two groups of support plates (31) of vertical plate-like structure, the two support plates (31) are vertically fixed by rods, an aluminum magnetic field box (4) of an upper open metal box-like structure is connected and fixed between the two groups of support plates (31), and the left and right sides of the aluminum magnetic field box (4) are A magnetic plate (5) is attached and fixed to the inner wall of each side, the two groups of magnetic plates (5) are parallel to each other, a sensor fixing frame (6) is provided above the magnetic field box (4), a Hall sensor (7) is fixed on the sensor fixing frame (6), a horizontal parallel rod (11) is fixed on one side of the sensor fixing frame (6) away from the support base (1), a rod fixture for fixing the metal rod to be measured is provided on the other side of the sensor fixing frame (6), and two groups of support plates (31) of the induction bracket (3) are provided with through holes for the metal rod to be measured and the parallel rod (11) to slide to form a rod hole (32).

2. The linear expansion coefficient measuring instrument based on the Hall effect according to claim 1, characterized in that: The rolling assembly (8) comprises: a connecting plate (81), a wheel frame (82), a rotating shaft (83), a first bearing (84), a rotating wheel (85), and a wheel sleeve (86); the connecting plate (81) is a plate-like structure, the connecting plate (81) is directly or indirectly fixed to the support plate (31) on the same side thereof, a wheel frame (82) of a plate-like structure is provided on both sides of the connecting plate (81), a rotating shaft (83) is provided on the top of each set of wheel frames (82), and there are two sets of rotating shafts (83) in total, the two sets of rotating shafts (83) are concentrically arranged, a rotating wheel (85) is rotatably matched on each set of rotating shafts (83) by means of the first bearing (84), and a wheel sleeve (86) is externally embedded and matched on the two sets of rotating wheels (85).

3. The linear expansion coefficient measuring instrument based on the Hall effect according to claim 2, characterized in that: The wheel sleeve (86) is made of a material with low thermal conductivity.

4. The linear expansion coefficient measuring tester based on the Hall effect according to claim 2, characterized in that: The connecting plate (81) cooperates with the support plate (31) through the leveling component (9), and the leveling component (9) comprises: a fixed plate (91), an upper support rod (92), a lower support rod (93), a sliding rod (94), a screw rod (95), a rotating handle (96), and a second bearing (97); the fixed plate (91) is a vertical plate-shaped structure, the fixed plate (91) is fixed to the side wall of the support plate (31), and two groups of cross beam brackets extending outward are respectively provided on the upper and lower parts of the support plate (31) to form an upper support rod (92) and a lower support rod (93), and a vertical sliding rod is provided between the upper support rod (92) and the lower support rod (93), and the connecting plate (81) is slidably matched on the sliding rod (94), and a screw rod (95) is threadedly connected to the lower part of the lower support rod (93), and the top of the screw rod (95) forms a rotational match with the connecting plate (81) through the second bearing (97).

5. The linear expansion coefficient measuring tester based on the Hall effect according to claim 4, characterized in that: A rotating handle (96) perpendicular to the screw rod (95) is connected below the screw rod (95).

6. The linear expansion coefficient measuring instrument based on the Hall effect according to claim 1, characterized in that: The sensor fixing frame (6) is provided with a three-jaw chuck (61) for fixing the metal rod to be measured, and the clamping center of the three-jaw chuck (61) and the flat rod (11) are coaxial.

7. The linear expansion coefficient measuring tester based on the Hall effect according to claim 1, characterized in that: The Hall sensor (7) comprises: a sensor body (71), a mounting tube (72), and a sensing end (73), wherein the sensor body (71) is fixed on a sensor fixing frame (6) by means of the mounting tube (72), the sensing end (73) of the sensor body (71) is located inside the sensor fixing frame (6) by means of a wire penetrating the mounting tube (72), and the sensor fixing frame (6) is made of non-magnetic material.

8. The linear expansion coefficient measuring tester based on the Hall effect according to claim 1, characterized in that: The heating tube (2) is covered with a heat-insulating tube (10) made of heat-insulating material.

9. The linear expansion coefficient measuring tester based on the Hall effect according to claim 1, characterized in that: The side of the heating tube (2) away from the induction bracket (3) is threadedly matched with a circumferentially arranged clamping bolt (21), and when all the clamping bolts are locked, the heating tube (2) and the metal rod to be measured can be clamped and fixed.

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