CN219608288U - Force sensor - Google Patents

Abstract

The present utility model provides a force sensor comprising: the metal base comprises a base body with a longitudinally extending through hole in the center, and the longitudinally proximal end of the base body transversely extends outwards to form a circle of first flange; a sealing groove is formed on the inner wall of the matrix; the sealing ring is arranged in the sealing groove; a sealing cover which forms a sealing cavity with the metal base towards one side of the longitudinal far end; at least two piezoresistors positioned in the sealing cavity, wherein the piezoresistors are correspondingly arranged on an insulating foundation arranged on the proximal end face of the matrix; and the circuit board is positioned in the sealing cavity and arranged on the proximal end face of the substrate, a plurality of abdication notches which are perpendicular to the longitudinal plane and avoid the insulation foundation are arranged on the periphery of the circuit board, and the piezoresistor is electrically connected with the circuit board. The force sensor can reduce the height difference between the surface of the circuit board and the surface of the piezoresistor, and is easy to bond and connect.

Description

Force sensor

Technical Field

The utility model relates to the technical field of sensors, in particular to a force sensor.

Background

Unlike conventional Brake systems, which transfer the driver's braking demand from the Brake pedal to the wheels through a hydraulic master cylinder, a hydraulic tube, and a hydraulically driven Brake caliper, the Mechanical Brake-by-wire (EMB) system is directly driven by an electric device to Brake, thus eliminating the need to install a hydraulic line or repair the hydraulic system; furthermore, due to the reduced space requirements of the engine compartment, the control software may be integrated into any suitable vehicle control with a suitable level of safety and sufficient computing power. In the case of autopilot, EMB is considered faster than traditional hydraulic systems and therefore has more time to calculate autopilot functions; finally, this would be advantageous for the driving range of electric vehicles and for carbon dioxide reduction, since EMB allows a truly zero resistance.

In the EMB system, the brake actuator needs to monitor the axial load of the brake shaft in real time all the time, the brake shaft usually slides in the ring member, and electronic elements such as a measuring circuit are arranged on the ring member to measure the surface stress change of the ring member under load and calculate the axial load. To ensure reliability and service life, it is desirable to have a good seal between the shaft and the ring to protect the electronic components. The measuring circuit needs to be attached to the ring, so that the circuit board can only be secured to the ring as much as possible in order to achieve a good seal, which makes the arrangement and connection between it and the measuring circuit difficult.

The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.

Disclosure of Invention

Aiming at the defects of the prior art, the utility model provides a force sensor for realizing reasonable arrangement and connection of a measuring circuit and a circuit board.

To achieve the above object, the present utility model provides a force sensor comprising:

the metal base comprises a base body with a longitudinally extending through hole in the center, and the longitudinally proximal end of the base body transversely extends outwards to form a circle of first flange; a sealing groove is formed on the inner wall of the matrix;

the sealing ring is arranged in the sealing groove;

a sealing cover which forms a sealing cavity with the metal base towards one side of the longitudinal far end;

at least two piezoresistors positioned in the sealing cavity, wherein the piezoresistors are correspondingly arranged on an insulating foundation arranged on the proximal end face of the matrix;

and the circuit board is positioned in the sealing cavity and arranged on the proximal end face of the substrate, a plurality of abdication notches which are perpendicular to the longitudinal plane and avoid the insulating foundation are arranged on the periphery of the circuit board, and the piezoresistor is electrically connected with the circuit board.

Preferably, the sealing cover comprises a cover plate positioned at one side of the longitudinal proximal end of the base body, and an inner cylinder and an outer cylinder which are formed by protruding the edges of the inner side and the outer side of the cover plate towards one side of the longitudinal distal end respectively, wherein the distal end of the outer cylinder is fixed on the proximal end face of the base body in a sealing way, and the inner cylinder is fixed in a through hole of the base body in a matching way and is abutted against the sealing ring.

Preferably, the insulating base is disposed on a substrate formed by protruding outwards from the middle of the proximal end surface of the base body, and the substrate is provided with open grooves for circumferentially separating the insulating base.

Preferably, the insulating base is arranged on a substrate formed by protruding towards the middle part of the proximal end face of the base body; every two circumferentially adjacent insulating foundations are separated by two open slots arranged on the substrate, a peninsula-shaped connecting part is formed between the two open slots, and the connecting part is fixedly connected with the distal end face of the circuit board.

Preferably, the middle part of the base body protrudes towards one side of the proximal end to form a boss, the edge of the base body forms a circle of pressed surface oppositely, and the base plate is arranged on the boss.

Preferably, the via hole is a stepped hole, and comprises a small hole at the far end and a large hole at the near end, wherein a step surface is formed at the joint of the small hole and the large hole, and the near end of the inner cylinder is abutted on the step surface.

Preferably, the inner barrel is interference fit within the aperture, the inner diameter of the inner barrel being smaller than the inner diameter of the aperture.

Preferably, the longitudinally distal end of the base is also formed by extending laterally outward, a ring of second flanges, the first and second flanges being longitudinally separated by a ring of isolation slots.

Preferably, the piezoresistors are four in pairs, the circuit board is provided with four constant resistors in pairs, and the piezoresistors and the constant resistors in pairs form two measuring circuits in a one-to-one correspondence.

Preferably, the base and cover plate are annular.

Drawings

FIG. 1 is a partial structural perspective view of a force sensor according to a preferred embodiment of the present utility model;

FIG. 2 is a partial structural top view of a force sensor according to a preferred embodiment of the present utility model;

FIG. 3 is an exploded view of a force sensor according to a preferred embodiment of the present utility model;

FIG. 4 is a top view of a force sensor according to a preferred embodiment of the present utility model;

FIG. 5 is a perspective cross-sectional view of a force sensor of a preferred embodiment of the present utility model taken along A-A shown in FIG. 4;

FIG. 6 is a plan cross-sectional view of a force sensor of a preferred embodiment of the present utility model taken along A-A shown in FIG. 4;

fig. 7 is a plan cross-sectional view of a substrate according to a preferred embodiment of the present utility model taken along A-A shown in fig. 4.

In the figure: 1. a metal base; 100. a via hole; 101. a base; 102. a flange; 103. a boss; 104. a substrate; 105. an insulating base; 106. a piezoresistor; 107. a conductor; 108. an open slot; 109. a wire; 110. a stepped hole; 110a, small holes; 110b, macropores; 110c, step surface; 111. sealing grooves; 112. sealing the cavity; 113. a connection part; 2. a circuit board; 201. a first conductive portion; 202. a second conductive portion; 200. a via hole; 203. conditioning the chip; 204. a yielding slot; 3. a seal ring; 400. a via hole; 401. an inner cylinder; 402. an outer cylinder; 403. a cover plate; 4. a sealing cover; 404. positioning holes; 405. a wire via; 502. a positioning part; 5. a threading frame; 501. a glue groove; 7. a lead wire; 102b, isolation trenches.

Detailed Description

The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings. The following examples are illustrative only and are not to be construed as limiting the utility model. In the following description, the same reference numerals are used to designate the same or equivalent elements, and duplicate descriptions are omitted.

In the description of the present utility model, it should be understood that the directions or positional relationships indicated by the terms "upper", "lower", "inner", "outer", "left", "right", etc. are based on the directions or positional relationships shown in the drawings, or the directions or positional relationships conventionally put in place when the inventive product is used, or the directions or positional relationships conventionally understood by those skilled in the art are merely for convenience of describing the present utility model and simplifying the description, and do not indicate or imply that the apparatus or elements referred to must have a specific direction, be configured and operated in a specific direction, and therefore should not be construed as limiting the present utility model.

In addition, the terms "mounted," "connected," "coupled," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present utility model can be understood as appropriate by those of ordinary skill in the art.

It should be further understood that the term "and/or" as used in the present description and the corresponding claims refers to any and all possible combinations of one or more of the listed items.

As shown in fig. 1 to 3, a force sensor of a preferred embodiment of the present utility model includes a metal base 1. The metal base 1 comprises a base body 101, the center of which base body 101 is provided with a longitudinally extending via 100. The longitudinal proximal end of the base body 101 extends laterally outward to form a loop of the first flange 102, i.e. the first flange 102 forms a cantilevered structure with respect to the body of the base body 101 in longitudinal cross section, thereby enabling a greater tensile or tensile stress to be developed at the proximal end face of the base body 101 when a force is applied to the flange 102 in the longitudinal direction. A seal groove 111 is formed on the inner wall of the base 101. A seal ring 3 is provided in the seal groove 111.

The force sensor of this embodiment further comprises a sealing cap 4 enclosing a sealing cavity 112 with the metal base 1. The containment cap 4 includes an inner barrel 401, an outer barrel 402 and a shroud plate 403. The shroud 403 is located on the longitudinally proximal side of the base 101, the inner barrel 401 is formed by the inner edge of the shroud 403 projecting toward the longitudinally distal side, and the outer barrel 402 is formed by the outer edge of the shroud 403 projecting toward the longitudinally distal side. The distal end of the outer tube 402 is sealed and fixed to the proximal end surface of the base 101 by laser welding or the like. The inner cylinder 401 is fixed in the through hole 100 of the base body 101 in a matched manner and is pressed against the sealing ring 3. A circuit board 2 is disposed in the sealed cavity 112 and is located on the proximal end surface of the base 101, and a via 200 is formed in the center of the circuit board 2. The varistor 106 is located within the sealed cavity 112. At least two piezoresistors 106 are correspondingly arranged on an insulating base 105 arranged on the proximal end face of the base body 101 and are electrically connected with the circuit board 2. The base 101 and the cover plate 403 are preferably annular for ease of manufacture. In use, the flange may be pressed distally or proximally longitudinally by a force applying member (not shown) through which one end of a pushrod (not shown) passes from the via 100 of the metal base 1, the via 200 of the circuit board 2, and the via 400 of the sealing cap 4 (i.e., the cavity of the inner barrel 401) to transfer force such as pedal force.

The insulating base 105 may be provided with two conductors 107 (e.g. pads) respectively connected to two ends of the varistor 106, and the circuit board 2 may be correspondingly provided with a plurality of first conductive portions 201, where the conductors 107 and the first conductive portions 201 may be connected by wires 109. The wire 109 may be an aluminum wire, which may be connected by a bonding machine.

The force sensor of the embodiment seals the circuit board by arranging the sealing cover with a specific structure, and the inner side is sealed by the sealing ring, so that the force sensor has a simple structure and low manufacturing cost; while measuring the force applied to the first flange, a higher measurement accuracy can be obtained.

In other embodiments, the periphery of the circuit board 2 is preferably provided with a plurality of yielding notches 204 that are formed to avoid the insulating base 105 in a plane perpendicular to the longitudinal direction, so that the circuit board 2 can avoid covering the insulating base 105 and the piezoresistors 106 thereon, and thus the thickness of the circuit board 2 can be reduced to the greatest extent (when the height is too high, it is difficult to achieve good bonding between the piezoresistors 106 and the circuit board 2 even if special bonding equipment is used), and meanwhile, the circuit board 2 can be electrically connected with the piezoresistors 106 conveniently. The thickness of the circuit board 2 is preferably 1mm or less. Therefore, the force sensor can reduce the height difference between the surface of the circuit board and the surface of the piezoresistor, and is easy to bond and connect.

In other embodiments, the insulating base 105 is preferably disposed on a substrate 104 formed by protruding toward the middle of the proximal end face of the base 101. The substrate 104 is provided with open grooves 108 for circumferentially separating the insulating base 105, so as to reduce the rigidity of the substrate 104 and improve the tensile stress or the tensile stress of the piezoresistor 106 under the same pressure to a certain extent, thereby improving the measurement accuracy.

In other embodiments, the insulating base 105 is preferably disposed on a substrate 104 formed by protruding toward the middle of the proximal end face of the base 101. Every two circumferentially adjacent insulating foundations 105 are separated by two open grooves 108 formed in the base plate 104. A peninsula-shaped connecting portion 113 is formed between the two open grooves 108. The connection portion 113 is fixedly connected to the distal end face of the circuit board 2. In this way, by fixing the circuit board 2 to the peninsula-shaped connection portion 113 on the substrate 104 by a simple means such as bonding, the influence of the assembly stress at the connection portion of the circuit board 2 and the base 101 on the varistor 106 is blocked, and the measurement accuracy can be further improved.

In other embodiments, it is preferred that the middle portion of the base 101 protrudes toward the proximal side to form a boss 103, and the edges of the base 101 face each other to form a ring of compression surfaces 114. The base plate 104 is disposed on the boss 103, which can facilitate positioning of the distal end of the outer cylinder 402 on the metal base 1, and can reduce rigidity of the base 101 to some extent.

In other embodiments, the via 100 is preferably a stepped hole 110 that includes a small hole 110a at the distal end and a large hole 110b at the proximal end. The junction of the small hole 110a and the large hole 110b forms a stepped surface 110c. The proximal end of the inner barrel 401 abuts against the stepped surface 110c. The inner barrel 401 may be interference fit within the aperture 110a to allow for quick manufacturing.

The inner diameter of the inner cylinder 401 is preferably smaller than the inner diameter of the small hole 110a, so that the force is prevented from being transmitted to the outer cylinder 402 to press the substrate 101 when the push rod 7 contacts the inner cylinder 401, and the force-receiving surface 114 of the outer edge of the substrate 101 is intensively pressed only by the force-applying member 6, so as to reduce measurement errors.

Referring to fig. 7 in combination, in other embodiments, the longitudinally distal end of the base 101 preferably also extends laterally outward to form a loop of the second flange 102a. The first flange 102 and the second flange 102a are longitudinally separated by a ring of separation grooves 102b, which facilitates assembly of the base 101.

In the above embodiments, the piezoresistors 106 are four in groups of two. The circuit board 2 is provided with four constant resistors in pairs. The two groups of piezoresistors 106 and the two groups of constant resistors form two measuring circuits in a one-to-one correspondence manner, so that the two measuring circuits are used as backup, namely correct measuring data can be provided when one measuring circuit works abnormally, and safety is improved. The measurement circuit may be a wheatstone bridge with two constant resistors opposite the opposite (i.e., non-adjacent) leg and two piezoresistors 106 opposite the opposite leg. The circuit board 2 may also be provided with a conditioning element 203 for conditioning the measurement signal and outputting the conditioned measurement signal.

In order to facilitate the output of the measurement signal, the plurality of leads 7 are electrically connected to the plurality of second conductive portions 202 correspondingly disposed on the circuit board 2 after the wire vias 405 are formed on the cover plate 403. A threading frame 5 is fixed to the proximal end side of the cover plate 403. The lead 7 passes through the glue groove 501 formed on the threading frame 5. Sealant is provided in the sealant groove 501. The distal end of the threading frame 5 may be outwardly protruded to form a positioning portion 502. The positioning portion 502 is sealed and inserted into the positioning hole 404 correspondingly formed on the cover plate 403, so as to facilitate assembly.

The scope of the present disclosure is defined not by the detailed description but by the claims and their equivalents, and all modifications within the scope of the claims and their equivalents are to be construed as being included in the present disclosure.

Claims (10)

1. A force sensor, comprising:

a metal base (1) comprising a base body (101) with a longitudinally extending through hole (100) in the center, wherein the longitudinally proximal end of the base body (101) extends outwards transversely to form a circle of first flanges (102); a seal groove (111) is formed on the inner wall of the base body (101);

a seal ring (3) provided in the seal groove (111);

a sealing cover (4) which surrounds a sealing cavity (112) with the metal base (1) towards the longitudinal distal end side;

at least two piezoresistors (106) positioned in the sealing cavity (112), wherein the piezoresistors (106) are correspondingly arranged on an insulating base (105) arranged on the proximal end face of the base body (101);

and the circuit board (2) is positioned in the sealing cavity (112) and is arranged on the end face of the proximal end of the base body (101), a plurality of abdication notches (204) which are perpendicular to the longitudinal plane and avoid the insulating base (105) are arranged on the periphery of the circuit board (2), and the piezoresistor (106) is electrically connected with the circuit board (2).

2. The force sensor according to claim 1, wherein the sealing cover (4) comprises a cover plate (403) located at the longitudinal proximal end side of the base body (101), and an inner cylinder (401) and an outer cylinder (402) formed by protruding the inner side edge and the outer side edge of the cover plate (403) towards the longitudinal distal end side respectively, the distal end of the outer cylinder (402) is fixed on the proximal end face of the base body (101) in a sealing way, and the inner cylinder (401) is fixed in the through hole (100) of the base body (101) in a matching way and is pressed against the sealing ring (3).

3. The force sensor according to claim 1, characterized in that the insulating base (105) is arranged on a base plate (104) formed by protruding outwards from the middle of the proximal end face of the base body (101), and that the base plate (104) is provided with open grooves (108) for circumferentially separating the insulating base (105).

4. The force sensor according to claim 1, characterized in that the insulating base (105) is provided on a substrate (104) formed by protruding towards the outside in the middle of the proximal end face of the base body (101); every two circumferentially adjacent insulating foundations (105) are separated by two open grooves (108) formed in the base plate (104), a peninsula-shaped connecting portion (113) is formed between the two open grooves (108), and the connecting portion (113) is fixedly connected with the distal end face of the circuit board (2).

5. The force sensor according to any of claims 3 to 4, characterized in that the middle part of the base body (101) protrudes towards the proximal side to form a boss (103), the edges of the base body (101) are opposite to form a circle of pressure surface (114), and the base plate (104) is arranged on the boss (103).

6. The force sensor of claim 1, wherein the via (100) is a stepped hole comprising a small hole (110 a) at a distal end and a large hole (110 b) at a proximal end, the junction of the small hole (110 a) and the large hole (110 b) forms a stepped surface (110 c), and the proximal end of the inner barrel (401) abuts against the stepped surface (110 c).

7. The force sensor of claim 6, wherein the inner barrel (401) is interference fit within the aperture (110 a), the inner barrel (401) having an inner diameter that is smaller than an inner diameter of the aperture (110 a).

8. The force sensor of claim 1, wherein the longitudinally distal end of the base body (101) is also formed by extending laterally outward, a ring of second flanges (102 a), the first flanges (102) being longitudinally separated from the second flanges (102 a) by a ring of isolation grooves (102 b).

9. The force sensor according to claim 1, wherein the piezo-resistors (106) are arranged in a group of four, the circuit board (2) is provided with four constant resistors in a group of four, and the two piezo-resistors (106) and the two constant resistors form two measuring circuits in a one-to-one correspondence.

10. The force sensor according to claim 1, characterized in that the base body (101) and the cover plate (403) are ring-shaped.