Limiting structure of load cell and load cell

Abstract

The application provides a limiting structure of a load cell and the load cell, and relates to the technical field of sensors. The limiting structure comprises a shell, a pull shaft and a limiting protrusion. The shell is a hollow cavity provided with an opening. The hollow cavity comprises a first limiting cavity and a second limiting cavity which are communicated. The first limiting cavity is relatively far from the opening. The minimum cross-sectional area of the first limiting cavity is greater than the maximum cross-sectional area of the second limiting cavity. The second limiting cavity is arranged between the first limiting cavity and the opening and is used for assembling a load bearing of the load cell. The pull shaft comprises a connecting end arranged in the hollow cavity and a free end arranged outside the opening. The load bearing is sleeved on the pull shaft. The elastic sheet of the load cell is arranged on the connecting end. The connecting end can move in the axial direction relative to the shell. The limiting protrusion is arranged on the pull shaft and can only move in the first limiting cavity. The application solves the problem that the stress of the pull shaft is too large and affects the service life and the measurement accuracy of the load cell.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sensors, in particular to a limiting structure of a load cell and the load cell. BACKGROUND

[0002] A load cell is a device that converts a mass signal into a measurable electrical signal output. There are various types of load cells, among which a strain gauge load cell measures weight by using the principle that the resistance of an electric resistance strain gauge changes when it deforms. However, when the load on the load cell is too large, the parts of the load cell will be damaged, thereby affecting the service life and measurement accuracy of the load cell. SUMMARY

[0003] Therefore, the embodiments of the present application provide a limiting structure of a load cell and the load cell, which can solve the above technical problems.

[0004] In a first aspect, the present application provides a limiting structure of a load cell, which comprises a shell, a pull shaft and a limiting protrusion, wherein the shell is a hollow cavity provided with an opening, the hollow cavity comprises a first limiting cavity and a second limiting cavity which are communicated, the first limiting cavity is relatively far away from the opening, and the minimum cross-sectional area of the first limiting cavity is greater than the maximum cross-sectional area of the second limiting cavity; the second limiting cavity is arranged between the first limiting cavity and the opening and is used to assemble a load bearing of the load cell. The pull shaft comprises a connecting end arranged in the hollow cavity and a free end arranged outside the opening, wherein the load bearing is sleeved on the pull shaft, an elastic sheet of the load cell is arranged on the connecting end, and the connecting end can move axially relative to the shell; the limiting protrusion is arranged on the pull shaft and can only move in the first limiting cavity.

[0005] In an embodiment, one end of the limiting protrusion facing the opening abuts against the load bearing.

[0006] In an embodiment, the first limiting cavity and the second limiting cavity are respectively cylindrical, and the limiting protrusion is a disc arranged circumferentially on the outer wall of the pull shaft.

[0007] In an embodiment, the disc is provided with a notch matched with a mounting platform protruding from the inner wall of the shell, wherein the mounting platform is used to assemble the elastic sheet.

[0008] In an embodiment, the outer edge of the notch of the disc is wavy, and the wavy shape comprises one or more wave crests.

[0009] In an embodiment, the plurality of wave crests is two, and the peak values of the two wave crests are different.

[0010] In an embodiment, the elastic sheet is arranged on the same side of the mounting platform and the disc and is away from the load bearing.

[0011] In one embodiment, a limiting surface is formed in the first limiting cavity, and the movement of the pull shaft in the direction of the opening is stopped when the end surface of the limiting protrusion close to the opening is in contact with the limiting surface.

[0012] The second aspect of the present application provides a load cell, which comprises the limiting structure of the load cell in any of the above embodiments.

[0013] According to the technical scheme of the present application, the limiting structure limits the maximum displacement of the pull shaft in the axial direction, i.e., limits the maximum deformation of the elastic sheet, so as to avoid damage of the elastic sheet due to excessive deformation, and to improve the service life of the elastic sheet. Meanwhile, the load bearing member is arranged on the pull shaft to replace the elastic sheet as the main force receiving component, so as to solve the problem that the elastic body is affected by creep after being subjected to force, thereby affecting the service life and the measurement accuracy of the load cell. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 Fig. 1 shows an exploded view of a limiting structure of a load cell according to an embodiment of the present application.

[0015] Figure 2 Fig. 2 shows a structural schematic view of a housing of the limiting structure of the load cell according to an embodiment of the present application.

[0016] Figure 3 Fig. 3 shows a sectional view of the load cell according to an embodiment of the present application.

[0017] 1 - housing; 11 - opening; 12 - first limiting cavity; 121 - limiting surface; 13 - second limiting cavity; 2 - load bearing member; 3 - pull shaft; 31 - free end; 32 - connecting end; 4 - disc body; 5 - mounting platform; 6 - elastic sheet. DETAILED DESCRIPTION

[0018] The technical scheme in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments.

[0019] The load cell mainly comprises a housing, a pull shaft, an elastic sheet having strain gauges mounted thereon, and the like. One end of the pull shaft is connected with the elastic sheet, and the other end is used to connect a load to be weighed. One end of the elastic sheet is connected with the housing, and the other end is connected with the pull shaft. When the load is connected to the pull shaft, the pull shaft drives the elastic sheet to deform, so that the weight of the load can be obtained according to the change of the resistance measured by the strain gauges on the elastic sheet. Since the elastic sheet is the force receiving component mainly subjected to the external force of the pull shaft in the load cell, the elastic sheet needs a certain thickness to ensure the rigidity requirement. However, the thicker elastic sheet will produce creep after long time use, thereby affecting the service life and the accuracy of the load cell.

[0020] In order to improve the service life and precision of the load sensor, a load bearing member with elasticity is further added in the load sensor to bear most of the external force applied to the pull shaft, so that the elastic body can be made thin and into an elastic sheet. In the case of thinning and force reduction of the elastic sheet, the elastic sheet is not prone to creep, thereby improving the service life of the elastic sheet and the measurement precision of the load sensor. However, the thinned elastic sheet will be damaged when the deformation amount exceeds the maximum value, thereby affecting the service life. Therefore, a limiting structure of the load sensor is provided in the embodiment to limit the maximum deformation amount of the elastic sheet, thereby improving the service life of the load sensor.

[0021] Figure 1 An exploded view of a limiting structure of a load sensor is shown.

[0022] The limiting structure includes a shell 1, a pull shaft 3, and a limiting protrusion. The shell 1 is a hollow cavity provided with an opening 11, and the hollow cavity includes a first limiting cavity 12 and a second limiting cavity 13 in communication. The first limiting cavity 12 is relatively far from the opening 11, and the minimum cross-sectional area of the first limiting cavity 12 is greater than the maximum cross-sectional area of the second limiting cavity 13. The second limiting cavity 13 is arranged between the first limiting cavity 12 and the opening 11 and is used to assemble a load bearing member 2 of the load sensor. The pull shaft 3 includes a connecting end 32 arranged in the hollow cavity and a free end 31 arranged outside the opening 11. The load bearing member 2 is sleeved on the pull shaft 3, an elastic sheet 6 of the load sensor is arranged on the connecting end 32, and the connecting end 32 can move axially relative to the shell 1. The limiting protrusion is arranged on the pull shaft 3 and can only move in the first limiting cavity 12.

[0023] The limiting structure provided in the embodiment utilizes the cooperation of the shell 1 and the limiting protrusion to limit the maximum displacement of the pull shaft 3 in the axial direction to the length of the first limiting cavity 12 in the axial direction of the pull shaft 3, thereby limiting the maximum deformation amount of the elastic sheet 6 fixed at one end of the connecting end 32. This avoids the problem that the elastic sheet 6 is irreversibly damaged when the weight exceeds the maximum range of the load sensor, thereby improving the service life of the elastic sheet 6.

[0024] It can be understood that the limiting protrusion can be part of the pull shaft 3 or an independent component fixed on the pull shaft 3 by clamping, sliding connection, threaded connection, or other means. It should be understood that the selection of the technical solution can be made according to the design requirements of the product.

[0025] In one embodiment, one end of the limiting protrusion facing the opening 11 abuts against the load bearing member 2.

[0026] Specifically, the limiting protrusion cooperates with other parts such as the adjusting bolt to compress the load bearing 2 (a disc spring assembly in the figure) in the hollow cavity of the shell 1, and when the pull shaft 3 is subjected to external force, the load bearing 2 is compressed as the main force receiving component, while the elastic sheet 6 provided on the pull shaft 3 is basically not subjected to force or subjected to very small force, and the elastic sheet 6 is mainly elastically deformed by the movement of the pull shaft 3, and then cooperates with the strain gauge provided on the elastic sheet 6 to realize the weighing.

[0027] The limiting structure provided by the embodiment replaces the elastic sheet 6 with the load bearing 2 as the main force receiving component, improves the service life of the elastic sheet 6, and at this time, the elastic sheet 6 is thin, the deformation of the elastic sheet 6 is more sensitive, and the precision of the elastic sheet 6 is improved.

[0028] In an alternative embodiment, the first limiting cavity 12 and the second limiting cavity 13 are respectively cylindrical, and the limiting protrusion is a disc body 4 provided circumferentially on the outer wall of the pull shaft 3. This structure is convenient for production and processing, and at the same time, the cavity is provided in a cylindrical shape to improve the service life of the shell 1.

[0029] Figure 2 The structure of the shell 1 of the limiting structure of the weighing sensor provided by an embodiment of the application is shown. As shown in Figure 2 Specifically, the disc body 4 is provided with a notch matched with the mounting platform 5 protruding from the inner wall of the shell 1, wherein the mounting platform 5 is used for assembling the elastic sheet 6. The mounting platform 5 is used for assembling the elastic sheet 6, the notch of the disc body 4 is matched with the structure of the mounting platform 5, and the assembly of the elastic sheet 6 is facilitated. It should be understood that the notch is not limited to one, and the number of notches can be adjusted according to the number of mounting platforms 5, and the number of mounting platforms 5 is determined by the structure of the elastic sheet 6, so that the number of mounting platforms 5 and the number of notches on the disc body 4 can be flexibly designed according to the structure of the elastic sheet 6.

[0030] It can be understood that the outer edge of the notch of the disc body 4 is in a wave shape, and the wave shape includes one or more wave peaks. Specifically, the mounting platform 5 is provided with a groove corresponding to the wave on the outer edge facing the hollow cavity, and the groove is provided with one or more. This structure design makes the disc body 4 have the effect of preventing the pull shaft 3 from rotating. It should be understood that the outer edge of the notch is not limited to the wave shape design, but can also be a boss or a zigzag structure, which cooperates with the structure on the outer edge of the mounting platform 5 to realize the anti-torsion effect of the pull shaft 3, thereby preventing the elastic sheet 6 from being damaged by the torsional force and improving the service life of the elastic sheet 6.

[0031] In one embodiment, the plurality of wave crests is two and the peak values of the two wave crests are not equal. This facilitates processing and improves the anti-twist effect. It should be understood that the plurality of wave crests is not limited to two, but can also be other numbers, and in the other numbers of wave crests, all the peak values of the wave crests can be equal, all the peak values of the wave crests can be unequal, or part of the peak values of the wave crests can be equal, which can be selected according to the specific requirements of product design.

[0032] In one embodiment, the elastic sheet 6 is arranged on the same side of the mounting platform 5 and the disc body 4 and is away from the load carrier 2. The elastic sheet 6 is not in direct contact with the load carrier 2, so that the elastic sheet 6 is not subjected to the elastic force of the load carrier 2, and the service life of the elastic sheet 6 is improved.

[0033] In one embodiment, a limiting surface 121 is formed in the first limiting cavity 12. When the end surface of the limiting protrusion close to the opening is in contact with the limiting surface 121, the movement of the pull shaft 3 in the direction of the opening 11 is stopped. The movement of the pull shaft 3 in the direction of the opening is prevented by the surface contact between the limiting surface 121 and the end surface of the limiting protrusion, the possibility of the radial movement or shaking of the pull shaft is reduced, and the measurement accuracy of the load sensor is improved.

[0034] Figure 3 A sectional view of a load sensor provided by one embodiment of the present application is shown.

[0035] The load sensor includes the limiting structure of the load sensor in any of the above embodiments.

[0036] According to the embodiments provided by the present application, the load sensor can further include an elastic sheet 6 and a load carrier 2. The elastic sheet 6 is arranged in the hollow cavity and deforms with the movement of the pull shaft 3. The load carrier 2 is arranged in the hollow cavity and is sleeved on the connecting end 32 of the pull shaft 3. After the free end 31 of the pull shaft 3 is subjected to an external force, the load carrier 2 is compressed under stress, and the elastic sheet 6 deforms under the driving of the pull shaft 3.

[0037] According to the technical scheme of the present application, the limiting structure limits the maximum displacement of the pull shaft 3 in the axial direction, i.e., limits the maximum deformation amount of the elastic sheet 6, avoids damage to the elastic sheet 6 due to exceeding the maximum deformation amount, and improves the service life of the elastic sheet 6. Meanwhile, the load carrier 2 is arranged on the pull shaft 3 to replace the elastic sheet 6 as the main force receiving component, thereby solving the problem of the influence of the elastic body on the service life and the measurement accuracy of the load sensor in the previous improved scheme.

[0038] In the description of the application, reference to "one embodiment", "some embodiments", "an example", etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. The appearances of the phrases "in one embodiment", "in some embodiments", "an example", etc., in various places in the specification are not necessarily all referring to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments or examples.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0040] In addition, the terms "first", "second", etc., are used herein only to describe various conditions, and are not to be construed as indicating or implying relative importance or a specific number of features indicated thereby, such that the features defined with "first", "second", etc., can include at least one of the features explicitly or implicitly.

[0041] The above description is merely illustrative of the application, and is not to be taken in a limiting sense. Any modification and / or equivalent arrangement of any of the above-described embodiments which falls within the scope of the application is intended to be included in the scope of the application.

Claims

1. A limiting structure for a weighing sensor, characterized in that, include: The housing is a hollow cavity with an opening. The hollow cavity includes a first limiting cavity and a second limiting cavity that are connected. The first limiting cavity is relatively far away from the opening, and the minimum cross-sectional area of ​​the first limiting cavity is greater than the maximum cross-sectional area of ​​the second limiting cavity. The second limiting cavity is disposed between the first limiting cavity and the opening and is used to assemble the load-bearing component of the weighing sensor. The pull shaft includes a connecting end disposed within the hollow cavity and a free end disposed outside the opening, wherein the load-bearing member is sleeved on the pull shaft, the elastic plate of the weighing sensor is disposed on the connecting end, and the connecting end is capable of axial movement relative to the housing; A limiting protrusion is disposed on the pull shaft and can only move within the first limiting cavity; The first limiting cavity and the second limiting cavity are both cylindrical, and the limiting protrusion is a disc circumferentially disposed on the outer wall of the pull shaft; the disc is provided with a notch adapted to the mounting platform protruding on the inner wall of the housing, wherein the mounting platform is used to assemble the elastic sheet.

2. The limiting structure according to claim 1, characterized in that, The end of the limiting protrusion facing the opening abuts against the load-bearing member.

3. The limiting structure according to claim 1, characterized in that, The outer edge of the notch in the disc is wavy, and the wavy shape contains one or more peaks.

4. The limiting structure according to claim 3, characterized in that, The plurality of peaks are two, and the peak values ​​of the two peaks are not equal.

5. The limiting structure according to claim 1, characterized in that, The elastic sheet is positioned on the same side of the mounting platform and the disk body, away from the load-bearing component.

6. The limiting structure according to claim 1, characterized in that, A limiting surface is formed within the first limiting cavity. When the end face of the limiting protrusion near the opening contacts the limiting surface, the movement of the pull shaft toward the opening direction stops.

7. A weighing sensor, characterized in that, The limiting structure includes the weighing sensor as described in any one of claims 1-6.

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