Force cell

Abstract

The utility model discloses a force transducer. The force transducer comprises a pressure-bearing elastic body which comprises a diaphragm, a bidirectional bearing port and a circular groove, and the circular groove is a groove body formed by the diaphragm, the bidirectional bearing port and the periphery of the pressure-bearing elastic body; the resistance strain gauge is attached to the back face, opposite to the circular groove, of the diaphragm; the bidirectional loading connecting shaft comprises a first bidirectional loading connecting shaft and a second bidirectional loading connecting shaft, and the first bidirectional loading connecting shaft and the second bidirectional loading connecting shaft are clamped in the bidirectional bearing port; and the loading rod comprises a loading rod connecting part, and the loading rod is fixed on the bidirectional loading connecting shaft.

Description

TECHNICAL FIELD

[0001] The utility model relates to the detection related technical field especially, a kind of force sensor. BACKGROUND

[0002] Force Sensor as a kind of device for measuring the force size that object is subjected to, can be converted into measurable electrical signal by the force exerted by object, to realize accurate measurement of force.This conversion process enables people to conveniently record, analyze and process the size information of force.

[0003] Now, traditional patch type strain gauge force sensor has size big, precision low etc.Problems.And most of the existing force sensor cannot consider pressure and tension two kinds of conventional force measurement mode, so that force sensor application is relatively single, and increase the cost of entire mechanical electronic system, also can bring more redundant mechanism. UTILITY MODEL CONTENT

[0004] The utility model provides a kind of force sensor, both can measure pressure and can measure tension, also can improve measurement precision.

[0005] The application provides a kind of force sensor, force sensor includes: pressure-elastic body (2), including diaphragm (22), bidirectional bearing port (24) and round groove (25), the round groove (25) is the groove body formed by the diaphragm (22) with the bidirectional bearing port (24) and the pressure-elastic body (2) periphery;Resistance strain gauge (7), the resistance strain gauge (7) is attached with the back of the diaphragm (22) opposite the round groove (25);Bidirectional loading connecting shaft (3), including first bidirectional loading connecting shaft (31) and second bidirectional loading connecting shaft (32), the first bidirectional loading connecting shaft (31) and the second bidirectional loading connecting shaft (32) are clamped in the bidirectional bearing port (24);Loading rod (4) includes loading rod connecting portion (41), and the loading rod (4) is fixed on the bidirectional loading connecting shaft (3).

[0006] In some embodiments of the application, further comprising: product shell (1), connect the diaphragm (22), and with the diaphragm (22) and enclose to form cavity (14).

[0007] In some embodiments of the application, further comprising: the bidirectional bearing port (24) is annular groove, in force sensor axial direction (Z), the bidirectional bearing port (24) includes the annular groove upper surface (241) far from the resistance strain gauge (7), and the annular groove lower surface (242) close to the resistance strain gauge (7).

[0008] In some embodiments of the present application, further comprising: the first bidirectional loading connecting shaft (31) comprises a first elongated portion (311) having a first protruding block (3111), the second bidirectional loading connecting shaft (32) comprises a second elongated portion (321) having a second protruding block (3211), and the first protruding block (3111) and the second protruding block (3211) are clamped to the bidirectional bearing port (24).

[0009] In some embodiments of the present application, further comprising: the first protruding block (3111) and / or the second protruding block (3211) are in contact with the upper surface (241) of the ring groove under external tension, and the first protruding block (3111) and / or the second protruding block (3211) are in contact with the lower surface (242) of the ring groove under external pressure.

[0010] In some embodiments of the present application, further comprising: the load cell further comprises a first bolt (6) that fixes the loading rod (4) on the bidirectional loading connecting shaft (3) through a second bolt hole (33) provided on the bidirectional loading connecting shaft (3) and a third bolt hole (42) provided on the loading rod (4).

[0011] In some embodiments of the present application, further comprising: the product shell (1) further comprises a first through hole (13), the pressure-bearing elastic body (2) further comprises a second through hole (26), the bidirectional loading connecting shaft (3) further comprises a third through hole (34), and the loading rod (4) further comprises a fourth through hole (43).

[0012] And, the first through hole (13), the second through hole (26), and the third through hole (34), and the fourth through hole (43) are in communication and correspond in position in the axial direction (Z) of the load cell.

[0013] In some embodiments of the present application, further comprising: the first bidirectional loading connecting shaft (31) and the second bidirectional loading connecting shaft (32) are connected by one or both of welding and bolting to form the third through hole (34).

[0014] In some embodiments of the present application, further comprising: a first bearing base (8) comprising a recess (81) and a fourth bolt hole (82); and a second bolt (9) that fixes the load cell in the recess (81) of the first bearing base (8) through a first bolt hole (12) provided on the product shell (1) and a fourth bolt hole (82) provided on the first bearing base (8).

[0015] In some embodiments of the present application, further comprising: a second bearing base (10) comprising a threaded protrusion (102) and a third bolt (103); the third bolt (103) fixes the load cell on the second bearing base (10) through a first bolt hole (12) arranged on the product shell (1) and a fifth bolt hole (101) arranged on the second bearing base (10); the threaded protrusion (102) is arranged at an end of the second bearing base (10) away from the product shell (1) and is used for fixing the second bearing base (10) and the load cell.

[0016] In some embodiments of the present application, further comprising: the PCB board (23) is connected with a conditioning chip through a wire harness (5), and the wire harness (5) passes through a recess (11) arranged on the product shell (1) and a wire harness hole (21) arranged on the pressure-bearing elastic body (2). BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort on the basis of these drawings.

[0018] Figure 1 is a whole structure diagram of a load cell provided by an embodiment of the present application;

[0019] Figure 2 is a cross-sectional structure diagram of a load cell provided by an embodiment of the present application;

[0020] Figure 3 is a cross-sectional schematic diagram of a load cell in a pressure state provided by an embodiment of the present application;

[0021] Figure 4 is a cross-sectional schematic diagram of a load cell in a tension state provided by an embodiment of the present application.

[0022] Figure 5 is a force schematic diagram of the internal structure of a pressure-bearing elastic body of a load cell provided by an embodiment of the present application.

[0023] The main reference signs in the drawings in the specification of the present application are explained as follows:

[0024] 1-product shell, 11-recess, 12-first bolt hole, 13-first through hole, 14-cavity;

[0025] 2-Pressure-elastic body, 21-wire harness hole, 22-diaphragm, 23-PCB board, 24-bidirectional load port, 241-ring groove upper surface, 242-ring groove lower surface, 25-circular groove, 26-second through hole;

[0026] 3-bidirectional load connection shaft: 31-first bidirectional load connection shaft, 311-first elongated part of the first bidirectional load connection shaft, 3111-first protruding block of the first elongated part, 32-second bidirectional load connection shaft, 321-second elongated part of the second bidirectional load connection shaft, 3211-second protruding block of the second elongated part, 33-third bolt hole, 34-third through hole;

[0027] 4-loading rod, 41-loading rod connecting part, 42-third bolt hole, 43-fourth through hole;

[0028] 5-wire harness;

[0029] 6-first bolt;

[0030] 7-resistance strain gauge;

[0031] 8-first load base, 81-groove, 82-fourth bolt hole;

[0032] 9-second bolt;

[0033] 10-second load base, 101-fifth bolt hole, 102-threaded protruding part;

[0034] 103-third bolt. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present application will be described clearly and completely in the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0036] In the description of the present application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0037] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0038] In the description of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, a direct connection, or an indirect connection through an intermediate medium; or they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances. To facilitate understanding of the technical solutions of this application, some terms used in this application are first explained.

[0039] As mentioned above, existing force sensors have low detection accuracy, and most force sensors can only measure either tension or pressure, making it impossible to detect both pressure and tension using a single sensor. To address these issues, this application provides a force sensor that not only has high detection accuracy but can also detect both pressure and tension. The technical solution of this application will be described in detail below. It should be noted that the order of description of the following embodiments is not intended to limit the preferred order of the embodiments of this application. Furthermore, the descriptions of each embodiment have their own emphasis; parts not described in detail in a certain embodiment can be referred to in the relevant descriptions of other embodiments.

[0040] refer to Figure 1 The force sensor provided in this application has an axial direction Z along its thickness. The force sensor includes: a product housing 1, a pressure-bearing elastomer 2, a bidirectional loading connecting shaft 3, a loading rod 4, a wiring harness 5, and a first bolt 6. Specifically, in the axial direction Z, the product housing 1 and the pressure-bearing elastomer are connected by laser welding; the first bidirectional loading connecting shaft 31 and the second bidirectional loading connecting shaft 32 are connected as a single unit by welding or bolting, forming a complete bidirectional loading connecting shaft 3; the loading rod 4 is fixed to the bidirectional loading connecting shaft 3 by the first bolt 6.

[0041] Continue to refer to Figure 1 and Figure 2 The product housing 1 includes a recess 11, a first bolt hole 12, a first through hole 13, and a cavity 14. The recess 11 is recessed in the side wall of the cavity 14 to facilitate the exit of the circuit harness 5. The through hole 13 is provided on the bottom of the cavity 14.

[0042] The elastic force measuring assembly includes a pressure-bearing elastic body 2 and a PCB board 23. The pressure-bearing elastic body 2 includes a wire harness hole 21, a diaphragm 22, a bidirectional bearing port 24, a circular groove 25, and a second through hole 26. The circular groove 25 is a groove formed by the diaphragm 22, the bidirectional bearing port 24, and the periphery of the pressure-bearing elastic body 2. The wire harness hole 21 communicates with the recess 11 in the axial direction Z of the force sensor, facilitating the exit of the circuit wire harness 5. The wire harness hole 21 and the wire harness 5 are located at any position on the cylinder of the product housing, which can be set according to actual needs. The PCB board 23 is attached to the side of the diaphragm 22 opposite to the back of the circular groove 25, and the opening on the PCB board 23 and the opening of the pressure-bearing elastic body form the second through hole 26. The bidirectional bearing port 24 is an annular groove on the pressure-bearing elastic body 2 surrounding the second through hole 26, including an upper surface 241 and a lower surface 242 of the annular groove that are arranged opposite each other.

[0043] The bidirectional loading connecting shaft 3 includes a first bidirectional loading connecting shaft 31, a second bidirectional loading connecting shaft 32, and a second bolt hole 33. The first bidirectional loading connecting shaft 31 has a first extension 311, which is engaged within the bidirectional bearing port 24. Specifically, the first extension 311 has a first protruding block 3111 that conforms to the upper surface 241 and lower surface 242 of the annular groove. Similarly, the second bidirectional loading connecting shaft 32 has a second extension 321, which is engaged within the bidirectional bearing port 24. Specifically, the second extension 321 has a second protruding block 3211 that conforms to the upper surface 241 and lower surface 242 of the annular groove. The first bidirectional loading connecting shaft 31 and the second bidirectional loading connecting shaft 32 are mirror images of each other and are connected as a single unit by welding or bolting, forming a third through hole 34 between the first bidirectional loading connecting shaft 31 and the second bidirectional loading connecting shaft 32.

[0044] refer to Figure 5 Preferably, when the loading rod 4 is subjected to tension and moves away from the resistance strain gauge 7, the first protrusion 3111 and / or the second protrusion 3211 are in contact with the upper surface 241 of the annular groove. At this time, the tension is transmitted from the loading rod 4 to the bidirectional loading connecting shaft 3 through the upper surface 241 of the annular groove. When the loading rod 4 is subjected to pressure and moves close to the resistance strain gauge 7, the first protrusion 3111 and / or the second protrusion 3211 are in contact with the lower surface 242 of the annular groove. At this time, the pressure is transmitted from the loading rod 4 to the bidirectional loading connecting shaft 3 through the lower surface 242 of the annular groove.

[0045] The loading rod 4 includes a loading rod connecting part 41, multiple third bolt holes 42, and a fourth through hole 43. Specifically, in the axial direction Z of the force sensor, the third bolt holes 42 communicate with the second bolt holes 33, meaning the first bolt 6 secures the bidirectional loading connecting shaft 3 and the loading rod 4 together using the third bolt holes 42 and the second bolt holes 33. Alternatively, the third bolt holes 42 and the second bolt holes 33 are used to secure the bidirectional loading connecting shaft 3 and the loading rod 4 together. The number of third bolt holes 42 and the second bolt holes 33 can be four, or other fixing configurations can be used. In other embodiments, the third bolt holes 42 and the second bolt holes 33 can also be connected and fixed in other ways, such as welding or adhesive bonding. The loading rod connecting part 41 can be threaded, but is not limited to this; any structure that serves as a connection and a force transmission mechanism falls within this structural range.

[0046] Continue to refer to Figure 1 and Figure 2 Along the axial direction Z of the force sensor, the first through hole 13, the second through hole 26, the third through hole 34, and the fourth through hole 43 are interconnected and their positions correspond one-to-one, used to fix the device or equipment to be tested. The pressure-bearing elastic body 2, the bidirectional loading connecting shaft 3, and the loading rod 4, which constitute the force sensor, can be made of the same material, such as stainless steel.

[0047] Example 1

[0048] The following diagram illustrates in detail the working state of the force sensor under pressure. Figure 3 A cross-sectional schematic diagram of a force sensor under pressure is shown according to an embodiment of this application.

[0049] like Figure 3As shown, the force sensor is bolted to the first support base 8 via a second bolt 9. Specifically, the first support base 8 has a groove 81, and a fourth bolt hole 82 is located at the bottom of the groove 81. In the axial direction Z of the force sensor, the fourth bolt hole 82 corresponds to the first bolt hole 12. The second bolt 9 secures the force sensor and the first support base 8 together through the fourth bolt hole 82 and the first bolt hole 12. The surface of the product shell 1 that adheres to the wall of the first support base 8 is flat, and the parallelism and flatness of the surface of the product shell 1 facing the wall of the first support base 8 and the surface of the first support base 8 facing the surface of the product shell 1 are within the error range. In other words, the surface of the product shell 1 facing the wall of the first support base 8 and the surface of the first support base 8 facing the surface of the product shell 1 are relatively parallel and completely adhered to each other. The aforementioned reference plane can be, for example, the ground or other configured reference planes; no limitation is made here. After the force sensor and the first bearing base 8 are connected, the loading rod 4 can apply downward force. At this time, the bidirectional loading connecting shaft 3 is subjected to the downward force of the loading rod 4, and the force borne by the bidirectional loading connecting shaft 3 is applied to the pressure-bearing surface of the pressure-bearing elastic body 2, that is, in the axial direction Z of the force sensor, the pressure-bearing surface is the lower end face of the bidirectional bearing port 24. At this time, the pressure-bearing elastic body 2 deforms due to the force, and the resistance strain gauge 7 attached to the side of the pressure-bearing elastic body 2 opposite to the back of the diaphragm 22 of the circular groove 25 is also deformed due to the influence of the internal stress of the metal. The resistance value of the resistance strain gauge 7 changes, and the lead wire connects the resistance strain gauge 7 to the PCB board 23. The resistance strain gauge 7 forms a Wheatstone bridge in the PCB board. Furthermore, the PCB board 23 leads out the change signal of the resistance strain gauge 7, and the pressure data is determined by the above change signal.

[0050] Example 2

[0051] The working principle and operating status of the force sensor when detecting tensile force are explained below with reference to the accompanying drawings. Figure 4 A cross-sectional schematic diagram of a force sensor under tension is shown according to an embodiment of this application.

[0052] like Figure 4As shown, the force sensor is bolted to the second support base 10 via a third bolt 103. Specifically, the side of the second support base 10 that contacts the force sensor has a fifth bolt hole 101. Horizontally, the fifth bolt hole 101 corresponds to the first bolt hole 12, and the third bolt 103 secures the force sensor and the second support base 10 together through the fifth bolt hole 101 and the first bolt hole 12. The wall surface where the product housing 1 of the force sensor contacts the second support base 10 is flat, and the parallelism and flatness of the surfaces of the product housing 1 and the second support base 10 are within the error range. In other words, the surfaces of the product housing 1 and the second support base 10 are relatively parallel to each other, parallel to a reference plane, and completely in contact with it. This reference plane can be, for example, the ground, or other designated reference planes; no limitation is made here.

[0053] After the force sensor and the second support base 10 are connected, the second support base 10 also includes a threaded protrusion 102 for horizontally fixing the force sensor. Taking the force sensor and the second support base 10 as an example of being placed horizontally, the force sensor is loaded horizontally by the loading rod 4. At this time, the bidirectional loading connecting shaft 3 is subjected to the force of the loading rod 4 in the horizontal direction. The bidirectional loading connecting shaft 3 applies the force to the pressure-bearing elastic body 2, that is, in the horizontal direction, the pressure-bearing surface is the side of the bidirectional bearing port 24 away from the second support base 10. At this time, the pressure-bearing elastic body 2 deforms due to the force, and the resistance strain gauge 7, which is attached to the side of the pressure-bearing elastic body 2 opposite to the back of the diaphragm 22 of the circular groove 25, also deforms due to the internal stress of the metal. The resistance value of the resistance strain gauge 7 changes, and the lead wire connects the resistance strain gauge 7 to the PCB board 23. The resistance strain gauge 7 forms a Wheatstone bridge in the PCB board. Furthermore, the PCB board 23 outputs the change signal of the resistance strain gauge 7, and the tensile force data is determined through the change signal.

[0054] It is understood that the force sensor and the second bearing base 10 can also be placed in any other direction, and there is no restriction on the placement direction of the force sensor and the second bearing base 10.

[0055] Therefore, the pressure-bearing elastomer 2 generates stress and strain under compression and tension. The resistance strain gauge 7 attached to the inner surface of the pressure-bearing elastomer 2 senses the stress and strain of the metal, thereby generating a differential resistance signal. The signal is output to the conditioning chip at the back end through the wiring harness 5. The conditioning chip at the back end amplifies the differential signal and then determines the pressure and tension information.

[0056] It is understood that, based on the force sensor provided in this application, when performing tensile and compressive force testing, only the corresponding bearing base needs to be replaced to detect the stress data. Thus, the force sensor provided in this application is simple to operate and provides high accuracy in measuring tensile or compressive force.

[0057] It should be noted that, for the sake of simplicity, the aforementioned method embodiments are described as a series of actions. However, those skilled in the art should understand that the present invention is not limited to the described order of actions, because according to the present invention, some steps can be performed in other orders or simultaneously.

[0058] In summary, although the present application has disclosed the preferred embodiments as described above, the above preferred embodiments are not intended to limit the present invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the scope defined in the claims.

Claims

1. A force sensor, characterized in that, The force sensor includes a pressure-bearing elastomer (2), comprising a diaphragm (22), a bidirectional bearing port (24), and a circular groove (25), wherein the circular groove (25) is a groove formed by the diaphragm (22), the bidirectional bearing port (24), and the periphery of the pressure-bearing elastomer (2); A resistance strain gauge (7) is attached to the back of the diaphragm (22) relative to the circular groove (25); a bidirectional loading connecting shaft (3) includes a first bidirectional loading connecting shaft (31) and a second bidirectional loading connecting shaft (32), which are snapped into the bidirectional bearing port (24); The loading rod (4) includes a loading rod connecting part (41), and the loading rod (4) is fixed on the bidirectional loading connecting shaft (3).

2. The force sensor according to claim 1, characterized in that, Also includes: The product casing (1) is connected to the diaphragm (22) and together with the diaphragm (22) forms a cavity (14).

3. The force sensor according to claim 1, characterized in that, The bidirectional bearing port (24) is an annular groove. In the axial direction (Z) of the force sensor, the bidirectional bearing port (24) includes an upper surface (241) of the annular groove that is farther away from the resistance strain gauge (7) and a lower surface (242) of the annular groove that is closer to the resistance strain gauge (7).

4. The force sensor according to claim 3, characterized in that, The first bidirectional loading connecting shaft (31) includes a first extension (311), the first extension having a first protrusion (3111). The second bidirectional loading connection shaft (32) includes a second extension (321), the second extension having a second protrusion (3211), the first protrusion (3111) and the second protrusion (3211) being engaged with the bidirectional bearing port (24).

5. The force sensor according to claim 4, characterized in that, The first protruding block (3111) and / or the second protruding block (3211) are attached to the upper surface (241) of the annular groove under external tension, and the first protruding block (3111) and / or the second protruding block (3211) are attached to the lower surface (242) of the annular groove under external pressure.

6. The force sensor according to claim 1, characterized in that, The force sensor also includes a first bolt (6), which fixes the loading rod (4) on the bidirectional loading connecting shaft (3) through a second bolt hole (33) on the bidirectional loading connecting shaft (3) and a third bolt hole (42) on the loading rod (4).

7. The force sensor according to claim 2, characterized in that, The product housing (1) further includes a first through hole (13), the pressure-bearing elastomer (2) further includes a second through hole (26), the bidirectional loading connecting shaft (3) further includes a third through hole (34), and the loading rod (4) further includes a fourth through hole (43); Furthermore, the first through hole (13), the second through hole (26), the third through hole (34), and the fourth through hole (43) are interconnected and corresponding in position in the axial direction (Z) of the force sensor.

8. The force sensor according to claim 7, characterized in that, The first bidirectional loading connecting shaft (31) and the second bidirectional loading connecting shaft (32) are connected by one or two of the following connection methods: welding connection and bolt connection to form the third through hole (34).

9. The force sensor according to claim 2, characterized in that, Also includes: The first support base (8) includes a groove (81) and a fourth bolt hole (82); The second bolt (9) fixes the force sensor in the groove (81) of the first support base (8) through the first bolt hole (12) provided on the product housing (1) and the fourth bolt hole (82) provided on the first support base (8).

10. The force sensor according to claim 2, characterized in that, Also includes: The second support base (10) includes a threaded protrusion (102) and a third bolt (103); The third bolt (103) fixes the force sensor to the second support base (10) through the first bolt hole (12) provided on the product housing (1) and the fifth bolt hole (101) provided on the second support base (10); The threaded protrusion (102) is disposed at one end of the second support base (10) away from the product housing (1) and is used to fix the second support base (10) and the force sensor.

11. The force sensor according to claim 1, characterized in that, The PCB board (23) is connected to the conditioning chip via a wire harness (5), which passes through a recess (11) on the product housing (1) and a wire harness hole (21) in the pressure-bearing elastomer (2).

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