Pressure Sensors

Abstract

The present application discloses a pressure sensor, comprising: a housing, the housing comprising an upper housing and a lower housing, the upper housing and the lower housing being arranged so as to form a cavity between the upper housing and the lower housing; a diaphragm, the diaphragm being arranged between the upper housing and the lower housing and dividing the cavity into an upper cavity and a lower cavity; a magnetic core, the magnetic core being arranged to be linked with the diaphragm; and a working spring, the working spring comprising a top end and a tail end, wherein the top end is supported to the upper housing, and the tail end is supported on the magnetic core; wherein at least one of the top end and the tail end of the working spring is provided with an adhesive layer. Compared with the prior art, the pressure sensor of the present application enables the working spring and the magnetic core to move as a whole, thereby improving the precision of the pressure sensor.

Description

Technical Field

[0001] The present application relates to a sensor, in particular to a pressure sensor for detecting operating parameters of household appliances. Background Art

[0002] In some household appliances, such as washing machines, some operating parameters should be sensed during use to ensure the correct operation of the household appliance, such as sensing the uniformity of distribution of the clothes to be washed in the washing machine basket, and the pressure and / or water level of the supplied water, etc.

[0003] In the prior art, pressure sensors are used to sense water pressure and / or water level. The pressure sensor generally includes a rigid housing that contains a deformable membrane that is sensitive to air pressure. When the pressure changes, the membrane deforms. The pressure sensor also includes a magnetic core, a working spring, and a coil, and the magnetic core cooperates with the membrane under the action of the working spring to reciprocate in response to the deformation of the membrane. The coil is fixed to the housing, and the inductance of the coil changes in response to the movement of the magnetic core. The coil and the capacitor are combined into an oscillation circuit, so that in response to the change in the inductance of the coil, the oscillation circuit can generate an oscillating electrical signal with a frequency change. Therefore, in use, the change in water level (i.e., pressure change) in the cylinder or basket of the household appliance can cause the oscillation frequency of the oscillating electrical signal to change. Summary of the invention

[0004] Pressure sensors have high requirements for precision, and existing production processes are difficult to meet the precision requirements of pressure sensors. After long-term experiments and observations, the applicant found that for the same pressure sensor, during assembly and use, the oscillation frequency generated by the oscillation circuit relative to pressure changes is not linear, or the oscillation frequency changes are unstable; for different pressure sensors, the oscillation frequency generated by the oscillation circuit relative to pressure changes is inconsistent.

[0005] Through long-term experiments and observations by the applicant, it was found that the above problems may be caused by the unstable relative positions of the magnetic core, the working spring and the coil. Specifically, when the magnetic core reciprocates in response to the deformation of the membrane, its motion trajectory does not completely correspond to the change in pressure. In the pressure sensor of the prior art, the working spring is generally made of metal. After assembly, there will inevitably be gaps of varying sizes between the end of the working spring and the plastic material, which may cause the working spring to shake or tilt to deviate from the predetermined position, and the deviation is also different. When the magnetic core reciprocates in response to the deformation of the membrane, the working spring may generate tiny internal vibrations with the magnetic core, affecting the motion trajectory of the magnetic core. Therefore, it is difficult for the prior art to meet the linearity and precision requirements of the oscillation frequency.

[0006] One of the purposes of the present application is to solve the above problems by providing an improved pressure sensor.

[0007] According to the first aspect of the present application, the present application provides a pressure sensor, comprising: a shell, the shell comprising an upper shell and a lower shell, the upper shell and the lower shell being arranged so as to form a cavity between the upper shell and the lower shell; a diaphragm, the diaphragm being arranged between the upper shell and the lower shell, and dividing the cavity into an upper cavity and a lower cavity; a magnetic core, the magnetic core being arranged to be linked with the diaphragm; and a working spring, the working spring comprising a top end and a tail end, wherein the top end is supported to the upper shell, and the tail end is supported on the magnetic core; wherein at least one of the top end and the tail end of the working spring is provided with an adhesive layer.

[0008] According to the above first aspect, the diaphragm includes a support body and a thin skin surrounding the support body, wherein the thin skin extends out from an edge of the support body; wherein the magnetic core is carried on the support body.

[0009] According to the above first aspect, a pad is provided between the magnetic core and the support body, and the magnetic core is supported on the pad.

[0010] According to the above first aspect, the pressure sensor further includes: a compensation elastic component, wherein the compensation elastic component is sandwiched between the lower housing and the diaphragm.

[0011] According to the first aspect above, the compensating elastic component includes an elastic rod disposed at the lower part of the support body of the diaphragm, the elastic rod extends downward from the support body and can contact the bottom of the lower shell, and the elastic rod can move along the axial direction of the magnetic core.

[0012] According to the above-mentioned first aspect, the pressure sensor also includes: an adjusting bolt, which is arranged at the top of the upper shell, wherein the top end of the working spring is supported to the adjusting bolt, and the adjusting bolt can be used to adjust the magnitude of the preset force applied by the working spring to the magnetic core; wherein the adhesive layer is arranged between the working spring and at least one of the magnetic core and the adjusting bolt, and the adhesive layer is used to bond the working spring to at least one of the magnetic core and the adjusting bolt.

[0013] According to the above first aspect, the adhesive layer includes a first adhesive layer, which is arranged between the top end of the working spring and the adjusting bolt, and the first adhesive layer is used to bond the top end of the working spring and the adjusting bolt.

[0014] According to the above first aspect, the adhesive layer includes a second adhesive layer, the second adhesive layer is arranged between the tail end of the working spring and the magnetic core, and the second adhesive layer is used to bond the tail end of the working spring and the magnetic core.

[0015] According to the above first aspect, the working spring is coaxially arranged with the magnetic core.

[0016] According to the above first aspect, the upper shell is connected to the upper part of the lower shell, and a third adhesive layer is provided at the connection between the upper shell and the lower shell.

[0017] According to the above first aspect, the pressure sensor also includes: a capacitor; and a coil, wherein the coil is fixed to the upper shell, and the coil cooperates with the magnetic core to form a variable inductance sensor; wherein the capacitor and the variable inductance sensor constitute a variable frequency oscillator.

[0018] According to the above first aspect, the pressure sensor also includes: at least one printed circuit board, the rear side of the at least one printed circuit board is connected to the upper shell, and the end of the coil is connected to the at least one printed circuit board; the lower shell is provided with a support rod, and the support rod is used to support the front side of the at least one printed circuit board; wherein a fourth adhesive layer is provided between the support rod and the at least one printed circuit board.

[0019] According to the above-mentioned first aspect, the coil includes at least one coil layer; the upper shell includes a cylindrical end, each coil layer includes several turns of wire, and each turn of the several turns of wire is wound side by side on the outside of the cylindrical end along the circumference of the cylindrical end; wherein, there is a fifth adhesive layer extending along the axial direction of the cylindrical end between at least two adjacent coil layers or between at least one coil layer and the cylindrical end.

[0020] According to the above first aspect, the fifth adhesive layer is disposed between the outermost coil layer and the inner coil layer, and is used to bond the outermost coil layer to the inner coil layer.

[0021] According to the first aspect above, the working spring includes several spiral coils, the top end and the tail end of the working spring include at least two spiral coils closely arranged side by side, and the top end and / or the tail end of the working spring are closed structures.

[0022] According to the above first aspect, the top end and / or the tail end of the working spring is a closed and ground structure.

[0023] In a second aspect of the present application, a pressure sensor is provided, comprising: a shell, the shell comprising an upper shell and a lower shell, the upper shell and the lower shell being arranged so as to form a cavity between the upper shell and the lower shell; a diaphragm, the diaphragm being arranged between the upper shell and the lower shell and dividing the cavity into an upper cavity and a lower cavity; a magnetic core, the magnetic core being carried on the diaphragm; and a working spring, the working spring comprising a top end and a tail end, wherein the top end is supported to the upper shell, and the tail end is supported on the magnetic core; wherein at least one of the top end and the tail end of the working spring is bonded by an adhesive process.

[0024] According to the above second aspect, the diaphragm includes a support body and a thin skin surrounding the support body, wherein the thin skin extends out from an edge of the support body; wherein the magnetic core is carried on the support body.

[0025] According to the above second aspect, the pressure sensor further includes: a compensation elastic component, wherein the compensation elastic component is sandwiched between the lower housing and the diaphragm.

[0026] According to the above-mentioned second aspect, the pressure sensor also includes: an adjusting bolt, which is arranged on the top of the upper shell, wherein the top end of the working spring is supported to the adjusting bolt, and the adjusting bolt can be used to adjust the magnitude of the preset force applied by the working spring to the magnetic core; wherein at least one of the top end and the tail end of the working spring is respectively bonded to the magnetic core and at least one of the adjusting bolt through a gluing process.

[0027] Compared with the prior art, the pressure sensor of the present application enables the working spring and the magnetic core to move as a whole, thereby improving the precision of the pressure sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A schematic diagram of the three-dimensional structure of an embodiment of the pressure sensor of the present application;

[0029] Figure 2A for Figure 1 An exploded structural diagram of the pressure sensor shown;

[0030] Figure 2B for Figure 1 A cross-sectional view of the pressure sensor in the height direction;

[0031] Figure 3 A cross-sectional view in the height direction of another embodiment of the pressure sensor of the present application;

[0032] Figure 4 A cross-sectional view in the height direction of another embodiment of the pressure sensor of the present application;

[0033] Figure 5A for Figure 1 The three-dimensional structure diagram of the pressure sensor after the cover is removed;

[0034] Figure 5B for Figure 5A Cross-sectional view along AA direction;

[0035] Fig. 6A and Figure 6B The specific structure of the coil is shown;

[0036] Fig. 7A and Figure 7B The specific structure of the working spring is shown;

[0037] Fig. 8A and Figure 8B A circuit diagram showing two embodiments of an oscillator circuit;

[0038] Fig. 9 The production process capability statistics of the pressure sensors of the prior art and the present application are shown. DETAILED DESCRIPTION

[0039] Various specific embodiments of the present application will be described below with reference to the accompanying drawings that form a part of this specification. It should be understood that although terms indicating directions, such as "front", "rear", "upper", "lower", "left", "right", "top", "bottom", etc., are used in this application to describe various example structural parts and elements of the present application, these terms are used here only for the purpose of convenience of description and are determined based on the example orientations shown in the accompanying drawings. Since the embodiments disclosed in the present application can be set in different directions, these terms indicating directions are only for illustration and should not be regarded as limitations. Where possible, the same or similar figure numbers used in this application refer to the same or similar parts.

[0040] Figure 1 FIG. 1 is a schematic diagram of a three-dimensional structure of an embodiment of the pressure sensor of the present application, and is used to illustrate the overall structure of the pressure sensor 100. Figure 1 As shown, the pressure sensor 100 includes a housing 105 and a cover 106 covering the housing 105. A joint pipe 104 is provided on the housing 105 at the bottom of the pressure sensor 100. The joint pipe 104 extends substantially along the length H of the pressure sensor 100. The joint pipe 104 is used to connect the internal volume of the housing 105 at least partially with the fluid of the liquid level to be sensed. The cover 106 on one side of the pressure sensor 100 along the length H thereof is provided with an extension portion 108. A signal socket 120 is provided at the end of the extension portion 108 for connecting the signal generated by the pressure sensor 100 to the control system of the washing machine.

[0041] Figure 2A and Figure 2B It is used to illustrate the specific structure of the pressure sensor 100, wherein Figure 2A for Figure 1 The exploded structure diagram of the pressure sensor 100 is shown in FIG. Figure 2B for Figure 1 The height direction cross-sectional view of the pressure sensor 100 is shown. Figure 2A and 2B As shown, the pressure sensor 100 includes a housing 105 and a cover 106, and the housing 105 includes an upper housing 201 and a lower housing 202. The cover 106 is connected to the lower housing 202 at the outside of the side wall of the lower housing 202, and the upper housing 201 is connected to the lower housing 202 at the inside of the side wall of the lower housing 202, and a cavity 203 is formed between the upper housing 201 and the lower housing 202. The cover 106 includes a main body 207 and an extension 108, wherein the main body 207 is roughly cylindrical. The lower housing 202 is also roughly cylindrical, and a mounting platform 238 is provided on the side. The cylindrical part of the lower housing 202 is connected to the main body 207 of the cover 106, for example, by clamping together. A clamping structure 232 is provided on the mounting platform 238 of the lower housing 202, through which the mounting platform 238 of the lower housing 202 can be connected to the extension 108 of the cover 106.

[0042] The upper shell 201 is cup-shaped and includes a base 241 and a cylindrical end 240. The base 241 of the upper shell 201 is connected to the lower shell 202 on the inner side of the side wall of the lower shell 202. As an example, the base 241 of the upper shell 201 is connected to the inner side of the side wall of the lower shell 202 by a gluing process, such as a dispensing process, to form a bonding layer 283 between the base 241 of the upper shell 201 and the lower shell 202. The bonding layer 283 can make the upper shell 201 and the lower shell 202 more firmly connected together, and will not move relative to each other in the upper and lower directions, thereby reducing the processing accuracy requirements for the connection part of the upper shell 201 and the lower shell 202.

[0043] like Figure 2A and 2B As shown, the pressure sensor 100 includes a pressure sensing part, an inductance sensing part and a signal output part. The pressure sensing part is used to sense the pressure of the fluid to be measured, the inductance sensing part is used to convert the sensed pressure into a certain amount of inductance, and the signal output part is used to convert the inductance into an electrical signal and output it to the control system of the household appliance.

[0044] Among them, the pressure sensing part of the pressure sensor 100 includes a diaphragm 210, which is arranged in a cavity 203 between an upper shell 201 and a lower shell 202. The diaphragm 210 can separate the cavity between the upper shell 201 and the lower shell 202 into an upper cavity 215 and a lower cavity 216 in a sealed (or liquid-tight) manner. The diaphragm 210 can deform in response to changes in the air pressure in the lower cavity 216. The deformation of the diaphragm 210 can reflect the pressure of the fluid to be measured. Specifically, the diaphragm 210 includes a support body 212 and a thin skin 213 arranged around the support body 212, and the thin skin 213 extends from the edge of the support body 212. The edge of the thin skin, which is thicker than the thin skin 213, is clamped between the upper shell 201 and the lower shell 202 so as to separate the upper cavity 215 from the lower cavity 216 in a sealed (or liquid-tight) manner. Among them, the thin skin 213 is arched upward to facilitate the deformation of the diaphragm 210. Among them, the upper chamber 215 is connected to the atmospheric environment, so that the pressure in the upper chamber 215 is atmospheric pressure. As an example, several through holes can be opened on the upper shell 201 to connect the upper chamber 215 with the atmospheric environment. The lower chamber 216 is connected to the cylinder of a household appliance, for example, through the joint pipe 104 at the bottom of the lower shell 202, so as to measure the liquid level (or water level) in the cylinder. Thus, the pressure in the lower chamber 216 depends on the pressure of the fluid to be measured, that is, the height of the liquid level (or water level) in the cylinder. Therefore, during the use of the household appliance, as the height of the liquid level (or water level) changes, the pressure difference between the upper chamber 215 and the lower chamber 216 also changes. The diaphragm 210 is affected by the pressure difference between the upper chamber 215 and the lower chamber 216, so that the diaphragm 210 is deformed as the pressure difference changes. The pressure of the fluid to be measured can be sensed by detecting the deformation of the diaphragm 210 .

[0045] The inductive sensing part of the pressure sensor 100 includes a magnetic core 218 and a coil 251, wherein the magnetic core 218 is carried on the support body 212 of the diaphragm 210, and the coil 251 is wound on the outside of the cylindrical end 240. As the diaphragm 210 deforms, the magnetic core 218 can move accordingly, and the amount of movement is the deformation size of the diaphragm 210. The magnetic core 218 is made of ferromagnetic material and can enter and exit the cylindrical end 240 of the upper shell 201, so that the inductance of the coil 251 wound outside the cylindrical end 240 changes, thereby forming a variable inductance sensor. As an example, the magnetic core 218 can be made of soft magnetic material.

[0046] Specifically, the magnetic core 218 may be in contact with the support body 212 or not in contact with the support body 212 and may be linked (or associated) with the support body 212, for example, carried by the support body 212. Figure 2BIn the embodiment shown, the magnetic core 218 can be directly supported on the support body 212. In other examples, the magnetic core 218 can also be supported on a pad 458 on the support body 212 (see Figure 4 ).according to Figure 2A and 2B In the illustrated embodiment, the diaphragm 210 further includes a mounting rod 214 disposed on the top of the support body 212, and the mounting rod 214 extends vertically upward from the top of the support body 212. The magnetic core 218 is cylindrical and is mounted on the mounting rod 214. As an example, the shape and size of the mounting rod 214 are set to match the magnetic core 218, and the mounting rod 214 is coaxial with the magnetic core 218, so that the magnetic core 218 can be stably supported by the support body 212 without relative movement with the support body 212.

[0047] The coil 251 is wound around the outer side of the cylindrical end 240 of the upper housing 201 and is coaxially arranged with the magnetic core 218 (i.e., the axis of the coil 251 coincides with the axis of the magnetic core 218). When the magnetic core 218 moves relative to the housing 105 following the deformation of the diaphragm 210, the magnetic core 218 can enter and exit the space defined by the coil 251, so that the inductance of the coil 251 changes, thereby converting the pressure of the fluid to be measured sensed into a certain amount of inductance.

[0048] The inductive sensing part of the pressure sensor 100 also includes a working spring 242, an adjusting bolt 243, and a compensating elastic component arranged opposite to the working spring 242. Figure 2A and 2B In the embodiment shown, the compensation elastic component includes an elastic rod 217. In other embodiments, the compensation elastic component may also include a compensation spring 318 (see Figure 3). Wherein, the working spring 242 is clamped between the upper shell 201 and the magnetic core 218, and the elastic rod 217 is clamped between the lower shell 202 and the diaphragm 210. Specifically, the working spring 242 includes a top end 247 and a tail end 248. According to an example of the present application, the top end 247 of the working spring 242 abuts against the adjusting bolt 243 inserted from the top end of the cylindrical end 240, and the tail end 248 of the working spring 242 abuts against the magnetic core 218. When the working spring 242 is compressed, the tail end 248 of the working spring 242 can apply a preset force to the magnetic core 218 for pushing the magnetic core 218 downward. By adjusting the depth of the adjusting bolt 243 screwed into the cylindrical end 240, the tightness of the working spring 242 in the initial state can be adjusted, thereby adjusting the magnitude of the preset force applied by the working spring 242 to the magnetic core 218. The compensating elastic component is configured to offset the gravity of the magnetic core 218, the diaphragm 210 and other components and the downward preset force applied by the working spring 242 through its elastic force or supporting force, so that even when the pressure change begins, the magnetic core 218 can move linearly with the pressure change, and thus the circuit can generate a linearly changing frequency signal. The top of the adjusting bolt 243 is also provided with a bolt fixing glue 245, which is used to fix the position of the adjusting bolt 243, thereby fixing the top 247 of the working spring 242.

[0049] According to an example of the present application, the compensating elastic component is as follows Figure 2B As shown, a flexible or elastic elastic rod 217 is arranged at the bottom of the support body 212 of the diaphragm 210, and the elastic rod 217 extends downward from the bottom of the support body 212. The lower end of the elastic rod 217 can contact the bottom of the lower shell 202, so that when the pressure sensor 100 is placed vertically during use, the flexible or elastic elastic rod 217 can produce a compensation effect for the gravity generated by the magnetic core 218, the diaphragm 210 and other components, and the preset force applied by the working spring 242. The elastic rod 217 can be made integrally with the support body 212. In addition, the elastic rod 217 is aligned with the center of the mounting rod 214, so that the elastic rod 217 and the magnetic core 218 are also coaxially arranged. The compensation elastic component can also include a compensation spring 318, which will be combined with Figure 3 Detailed description. A protruding element 253 is provided at the bottom of the lower housing 202. The protruding element 253 is a hollow tubular structure and can at least partially accommodate the elastic rod 217, and is used to support the bottom end of the elastic rod 217. The height of the protruding element 253 is set so that during the up and down movement of the elastic rod 217, the elastic rod 217 is always partially accommodated in the protruding element 253 and will not escape therefrom, so that the elastic rod 217 can move along a desired trajectory. By providing the protruding element 253, the position of the elastic rod 217 can be limited.

[0050] In such Figure 2B In the illustrated embodiment, the top 247 of the working spring 242 is connected to the adjusting bolt 243 by an adhesive process, such as a dispensing process, so as to form an adhesive layer 281 between the top 247 of the working spring 242 and the adjusting bolt 243. This arrangement can ensure that the relative position of the working spring 242 between the adjusting bolt 243 and the magnetic core 218 remains unchanged, so that the axis of the working spring 242 can be consistent with the axis of the magnetic core 218 and the coil 251, and the working spring 242 cannot deviate from its axial movement. Therefore, when the positions of the adjusting bolt 243 and the elastic rod 217 are constant, the preset force applied by the working spring 242 to the magnetic core 218 remains unchanged, and the working spring 242 and the magnetic core 218 can move linearly as a whole with the change of pressure. As a result, the rate of change of the inductance of the coil 251 relative to the pressure remains stable, and the rate of change of the oscillation frequency generated by the oscillation circuit relative to the pressure change also remains stable. By limiting the position of the working spring 242 through the gluing process, it is also possible to ensure that the initial position of the magnetic core 218 is consistent each time the pressure sensor 100 is assembled, and the magnetic core 218 can return to the initial position after each measurement. Therefore, the initial oscillation frequency generated by the oscillation circuit relative to the pressure change remains consistent. Even when the pressure sensor 100 is subjected to external force (for example, during transportation), the working spring 242 in the pressure sensor 100 will not be deflected, and the relative positions between the working spring 242, the magnetic core 218 and the coil 251 can still be kept fixed, so it will not affect the accuracy of the measurement results of the pressure sensor 100. Of course, in other embodiments, the tail end 248 of the working spring 242 and the magnetic core 218 can be connected together by a gluing process to form a bonding layer 382 between the tail end 248 of the working spring 242 and the magnetic core 218 (see Figure 3 ).

[0051] Thus, the elastic rod 217 and the working spring 242 support the magnetic core 218 in its initial position. In the initial position of the magnetic core 218, the pressure in the upper cavity 215 and the lower cavity 216 are substantially equal, and the diaphragm 210 does not deform. During the use of the household appliance, as the liquid level of the fluid to be measured increases, the air pressure in the lower cavity 216 gradually increases, so that the upward pressure on the diaphragm 210 gradually increases, causing the diaphragm 210 to deform, and the thin skin 213 moves upward, driving the magnetic core 218 to move upward until it enters the space defined by the coil 251, and the coil 251 generates a certain amount of inductance. The upward movement of the magnetic core 218 compresses the working spring 242. As the liquid level drops, the air pressure in the lower cavity 216 gradually decreases, and the working spring 242 rebounds, pushing the magnetic core 218 to move downward.

[0052] The signal output part of the pressure sensor 100 includes a printed circuit board 260, which is disposed between the upper housing 201 and the cover 106. The printed circuit board 260 is roughly rectangular in shape, and its length direction is the same as the length direction of the pressure sensor 100. The rear side of the printed circuit board 260 in the length direction is connected to the top of the cylindrical end 240, and the front side of the printed circuit board 260 in the length direction is provided with a pair of U-shaped grooves 265 with opposite groove bottoms, which are used to cooperate with the support rod 235 erected on the mounting platform 238 of the lower housing 202. Two pins 262 (see Figure 5A ), the two ends 252 of the coil 251 are respectively wound around the pins 262 to connect the coil 251 to the circuit on the printed circuit board 260. The printed circuit board 260 is also provided with capacitors 568 and 569 (see Figure 5A ), capacitors 568, 569 and coil 251 together form an oscillating circuit (i.e., a frequency-variable oscillator). When the magnetic core 218 moves up and down and affects the inductance of the coil 251, the oscillating circuit can generate a linearly varying frequency signal according to the varying inductance of the coil 251.

[0053] Thus, during the use of the household appliance (e.g., washing machine), as the height of the liquid level (or water level) to be measured changes, that is, the pressure of the fluid to be measured changes, the diaphragm 210 is deformed, and the magnetic core 218 can move up and down, entering and exiting the cylindrical end 240 of the upper shell 201. According to the amount of the magnetic core 218 entering the space defined by the coil 251 outside the cylindrical end 240, the coil 251 generates a certain amount of inductance. The oscillation circuit then generates a linearly changing frequency signal according to the changing inductance of the coil 251, and transmits the frequency signal to the control system of the household appliance (e.g., washing machine).

[0054] Figure 3 A cross-sectional view in the height direction of another embodiment of the pressure sensor of the present application is shown. Figure 2B The structures of the embodiments shown are substantially the same, except that: Figure 3 The compensation elastic component in the pressure sensor shown also includes a compensation spring 318. Figure 3As shown, the compensation elastic component is a combination of an elastic rod 217 and a compensation spring 318. The compensation spring 318 is sandwiched between the support body 212 and the bottom of the lower shell 202, and is sleeved on the outside of the protruding element 253. By adjusting the depth of the adjusting bolt 243 screwed into the cylindrical end 240, the tightness of the working spring 242 and the compensation spring 318 in the initial state can be adjusted, thereby adjusting the size of the preset force applied by the working spring 242 and the compensation spring 318 to the magnetic core 218 from both sides. The additional compensation spring 318 can better compensate for the gravity of the magnetic core 218, the diaphragm 210 and other components, so that when the air pressure in the lower chamber 216 begins to change, the frequency signal output changes linearly. At the same time, the adjustability of the compensation elastic component is increased.

[0055] like Figure 3 As shown, the tail end 248 of the working spring 242 and the magnetic core 218 are connected together by a gluing process, such as a dispensing process, to form a bonding layer 382 between the tail end 248 of the working spring 242 and the magnetic core 218. The bonding layer 382 can also ensure that the relative position of the working spring 242 between the adjusting bolt 243 and the magnetic core 218 does not change, and the working spring 242 cannot deviate from its axial movement, thereby achieving the same effect as the bonding layer 281. As an embodiment, only one of the bonding layer 281 and the bonding layer 382 can be provided to increase the flexibility of assembling the internal components of the pressure sensor.

[0056] Figure 4 A cross-sectional view in the height direction of an embodiment of the pressure sensor of the present application is shown. Figure 2B The structures of the embodiments shown are substantially the same, except that a pad 458 is provided between the magnetic core 218 and the support body 212. The magnetic core 218 is supported on the pad 458 so that the magnetic core 218 is indirectly supported on the support body 212, and the magnetic core 218 and the pad 458 move up and down together with the deformation of the diaphragm 210.

[0057] Figure 5A for Figure 1 The three-dimensional structure diagram of the pressure sensor 100 after removing the cover 106 is shown. Figure 5B for Figure 5A The cross-sectional view taken along the AA line is used to illustrate the specific structure of the printed circuit board 260 of the pressure sensor 100 .

[0058] like Figure 5A and 5BAs shown, the printed circuit board 260 is assembled on the top of the upper housing 201, and the two ends 252 of the coil 251 are respectively wound on the two pins 262 to connect the coil 251 with the circuit on the printed circuit board 260. A chip 261 is installed on the printed circuit board 260. The chip 261 is, for example, a sensor working chip. Two capacitors 568 and 569 are also installed on the printed circuit board 260, and these two capacitors 568 and 569 form an oscillation circuit together with the coil 251. It is worth noting that in addition to the chip 261 and capacitors 568 and 569 shown, other chips, capacitors or other electrical components can also be installed on the printed circuit board 260. In addition, the support rod 235 near the snap-fit ​​structure 232 on the lower housing 202 is used to assist in supporting the printed circuit board 260 from the front side of the printed circuit board 260. The front side of the printed circuit board 260 is used to be connected to the signal socket 120 to output the output signal of the oscillation circuit on the printed circuit board 260 through the signal socket 120.

[0059] The bottom of the U-shaped groove 265 on the printed circuit board 260 and the support rod 235 can also be connected together by an adhesive process, such as a dispensing process, to form an adhesive layer 584 between the bottom of the U-shaped groove 265 and the support rod 235. This arrangement can make the connection of the printed circuit board 260 more secure, and even when the pressure sensor 100 is subjected to external force (for example, during transportation), the printed circuit board 260 will not shake on the upper housing 201.

[0060] Fig. 6A and 6B The specific structure of the coil 251 is shown, wherein Fig. 6A is a schematic diagram of the three-dimensional structure of the coil 251, Figure 6B for Fig. 6A The main view of Fig. 6A and 6BAs shown, according to different application requirements, the coil 251 may include one or more coil layers 654 arranged along the radial direction of the cylindrical end 240. Each coil layer 654 includes a plurality of coils 655 arranged side by side along the length direction of the cylindrical end 240, and each coil 655 is wound side by side on the outside of the cylindrical end 240 along the circumference of the cylindrical end 240. At least two adjacent coil layers 654 are connected together by an adhesive process, such as a dispensing process, to form an adhesive layer 685 between at least two adjacent coil layers 654 to prevent the coil 251 from loosening. Alternatively, the innermost coil layer 654 and the cylindrical end 240 are connected together by an adhesive process to form an adhesive layer 685 between the innermost coil layer 654 and the cylindrical end 240. As an example, when the number of layers of the coil 251 is small, the adhesive layer can also be formed only between the outermost coil layer and the adjacent coil layer. It should be understood that during the gluing process, the glue may also penetrate from the outside to the inside between other adjacent coil layers to form the adhesive layer 685. As an example, the adhesive layer 685 is in the shape of a long strip extending from the top of the cylindrical end to the bottom along the axial direction of the cylindrical end. On the one hand, the adhesive layer 685 is set in this way, only a small amount of glue is needed to connect the coil layers 654 together. On the other hand, the adhesive layer 685 will not affect the coil 251's sensing of the position of the magnetic core 218, nor will it affect the coil 251's generation of corresponding inductance. As a result, the structure of the coil 251 is more solid, and when the magnetic core 218 moves up and down, the coil 251 can stably generate a corresponding amount of inductance.

[0061] Fig. 7A and 7B The specific structure of the working spring 242 is shown, wherein Fig. 7A is a schematic diagram of the three-dimensional structure of the working spring 242, Figure 7B for Fig. 7A The main view of Fig. 7A and 7BAs shown, the working spring 242 is a cylindrical helical spring, which is formed by connecting a number of helical coils 749. Most of the adjacent helical coils 749 are spaced a certain distance apart, so that the working spring 242 can be compressed. The helical coils 749 at the ends of the working spring 242 are not spaced apart. As an example, the top 247 of the working spring 242 includes two helical coils 749 that are closely attached to each other, and the tail 248 of the working spring 242 also includes two helical coils 749 that are closely attached to each other. The helical coils 749 at the top 247 and the tail 248 of the working spring 242 enable the working spring 242 to stand straight, be clamped between the adjusting bolt 243 and the magnetic core 218, and be flush with the lower surface of the adjusting bolt 243 and the upper surface of the magnetic core 218, so as to keep the coaxial arrangement of the working spring 242, the magnetic core 218 and the coil 251. At this time, the two ends of the working spring 242 do not participate in the deformation. As an example, the spiral coil 749 of the top end 247 and the tail end 248 of the working spring 242 is a closing structure, and the ends may be ground or not. It is understandable that the closing structure with the ends ground can ensure that the working spring 242 is coaxially arranged with the magnetic core, but the cost is high. In some embodiments, in order to save costs, the ends of the working spring 242 may not be ground. In the embodiments of the present application, the ends of the working spring are fixed by an adhesive process without grinding the ends of the working spring, which can also achieve better results.

[0062] Fig. 8A and 8B The circuit structure schematic diagram of the oscillation circuit on the printed circuit board 260 is shown to illustrate the circuit principle of generating a linearly changing oscillation frequency as the magnetic core 218 moves. In the two examples shown in 8A and 8B, there are different numbers of capacitors in the oscillation circuit to meet different needs. The coil 251 inside the pressure sensor 100 is equivalent to the inductor L 251 in the figure. The different pressures cause the position of the magnetic core 218 to change, and thus the inductance of the inductor L 251 also changes. Among them, Fig. 8A The oscillating circuit 890 shown includes only one capacitor 867, which forms a parallel circuit with the coil 251. Figure 8B The oscillating circuit 898 shown includes two capacitors 568 and 569, which are connected in series and then in parallel with the coil 251. The capacitors are, for example, resonant frequency-selective capacitors.

[0063] like Fig. 8A As shown, the inductor L251 and the capacitor C867 form a parallel frequency selection network, the integrated circuits U1891 and U2892 are used in parallel with the parallel frequency selection network composed of the inductor L251 and the capacitor C867 as positive feedback amplifiers, and the integrated circuit U3893 is used for waveform shaping to output a square wave signal. The linear frequency of the circuit output is: L in the formula represents the inductance of the coil 251 .

[0064] like Figure 8B As shown, the inductor L 251 and the capacitors C1 568 and C2 569 form a standard capacitor three-point oscillation circuit. The integrated circuit U1 894 is used as an inverting amplifier in parallel with the capacitor three-point oscillation circuit. The integrated circuit U2 895 is used for waveform shaping to output a square wave signal. The linear frequency of the circuit output is: L in the formula represents the inductance of the coil 251 .

[0065] Therefore, when the working spring 242 is fixed by the gluing process, the magnetic core 218 can move up and down in response to the change in pressure, so that the inductance of the coil 251 changes, and a linearly changing oscillation frequency is obtained. As an example, a plurality of integrated circuits U1, U2, U3 and other components can be set on a household appliance using the pressure sensor of the present application to form a Fig. 8A , Figure 8B However, a plurality of integrated circuits U1, U2, and U3 may be provided on the pressure sensor to form a circuit structure as shown in FIG. Fig. 8A , Figure 8B The circuit structure in the embodiment directly outputs the result signal, and all capacitors and other electrical components can also be arranged in the household appliance using the pressure sensor of the present application.

[0066] Fig. 9 Statistical results of the production process capabilities of the pressure sensor 900 of the prior art and the pressure sensor 100 of the present application are shown in FIG. In this embodiment, the pressure sensor 900 of the prior art does not have the adhesive layers 281 and 382, ​​and the working spring 242 is directly clamped between the adjusting bolt 243 and the magnetic core 218. Optionally, the pressure sensor 900 of the prior art may also not have the adhesive layers 283, 584 and 685.

[0067] The joint pipes 104 of the pressure sensor 900 of the prior art and the pressure sensors 100 of the present application are connected to the preset fluid respectively to provide the fluid with the preset pressure to the pressure sensor. When the same pressure is provided to each pressure sensor, the circuit output frequency (i.e., oscillation frequency) of the pressure sensor 900 and the pressure sensor 100 is measured respectively, and the following is obtained: Fig. 9 The normal distribution diagram is shown. Fig. 9 As shown, the pressure distribution measured by the pressure sensor 900 is shorter and wider, indicating that the individual differences between the pressure sensors 900 are large. However, the pressure distribution measured by the pressure sensor 100 is taller and narrower, indicating that the individual differences between the pressure sensors 100 are small.

[0068] When fluids of different pressures are provided to the pressure sensor 100 of the present application, the circuit output frequency (ie, oscillation frequency) varies linearly with the pressure, indicating that the output frequency of the pressure sensor 100 has good stability and the measurement result is reliable.

[0069] The pressure sensor 100 of the present application is bonded and fixed with the working spring 242 and the adjusting bolt 243 or the magnetic core 218 by an adhesive process, so that the relative position of the working spring 242 between the adjusting bolt 243 and the magnetic core 218 is fixed, and the working spring 242 cannot deviate from its axial movement, so that the preset force applied by the working spring 242 to the magnetic core 218 will not change, and the working spring 242 and the magnetic core 218 can move linearly as a whole with the change of pressure to obtain a linearly changing oscillation frequency. Therefore, even if the pressure sensor 100 is subjected to external force (for example, during transportation), the working spring 242 in the pressure sensor 100 will not be deflected, and the relative position between the working spring 242, the magnetic core 218 and the coil 251 can still be determined, so it will not affect the accuracy of the measurement result of the pressure sensor 100. The pressure sensor 100 can make the pressure and inductance correspond more accurately by improving the precision of the inductance sensing part. After the inductance is converted into an oscillation frequency, the pressure can be linearly related to the oscillation frequency.

[0070] The adhesive layer in the present application is formed by first applying glue or smearing glue on the corresponding parts and then waiting for the glue to solidify. The process of forming the adhesive layer is a gluing process or a bonding process. The glue used in the present application has certain high temperature resistance, weather resistance and water resistance. As an example, the glue is a silicone rubber system or an epoxy resin system.

[0071] Although the present application will be described with reference to the specific embodiments shown in the accompanying drawings, it should be understood that the pressure sensor of the present application can have many variations without departing from the spirit and scope of the teachings of the present application. The components and / or structures in the various embodiments of the present application can be combined in various ways where possible, which are all within the scope of protection of the present application. Those of ordinary skill in the art will also appreciate that there are different ways to change the parameters in the embodiments disclosed in the present application, all falling within the spirit and scope of the claims of the present application.

Claims

1. A pressure sensor, characterized in that include: A housing (105), the housing (105) comprising an upper housing (201) and a lower housing (202), wherein the upper housing (201) and the lower housing (202) are arranged so as to form a cavity between the upper housing (201) and the lower housing (202); A diaphragm (210), wherein the diaphragm (210) is disposed between the upper housing (201) and the lower housing (202), and divides the cavity into an upper cavity (215) and a lower cavity (216); a magnetic core (218), the magnetic core (218) being configured to be linked with the diaphragm (210); and A working spring (242), the working spring (242) comprising a top end (247) and a tail end (248), wherein the top end (247) is supported on the upper shell (201), and the tail end (248) is supported on the magnetic core (218); Wherein, at least one of the top end (247) and the tail end (248) of the working spring (242) is provided with an adhesive layer (281, 382).

2. The pressure sensor according to claim 1, wherein: The diaphragm (210) comprises a support body (212) and a thin skin (213) surrounding the support body (212), wherein the thin skin (213) extends out from an edge of the support body (212); Wherein, the magnetic core (218) is carried on the support body (212).

3. The pressure sensor according to claim 2, characterized in that: A pad (458) is provided between the magnetic core (218) and the support body (212), and the magnetic core (218) is supported on the pad (458).

4. The pressure sensor according to claim 1, characterized in that Also includes: A compensating elastic component (217, 318), wherein the compensating elastic component (217, 318) is sandwiched between the lower housing (202) and the diaphragm (210).

5. The pressure sensor according to claim 4, characterized in that: The compensating elastic component (217, 318) comprises an elastic rod (217) arranged at the lower part of the support body (212) of the diaphragm (210), the elastic rod (217) extending downward from the support body (212) and capable of contacting the bottom of the lower shell (202), and the elastic rod (217) is capable of moving along the axial direction of the magnetic core (218).

6. The pressure sensor according to claim 1, characterized in that Also includes: an adjusting bolt (243), the adjusting bolt (243) being arranged at the top of the upper shell (201), wherein the top end (247) of the working spring (242) is supported on the adjusting bolt (243), and the adjusting bolt (243) can be used to adjust the magnitude of a preset force applied by the working spring (242) to the magnetic core (218); Wherein, the adhesive layer (281, 382) is arranged between the working spring (242) and at least one of the magnetic core (218) and the adjusting bolt (243), and the adhesive layer (281, 382) is used to bond the working spring (242) to at least one of the magnetic core (218) and the adjusting bolt (243).

7. The pressure sensor according to claim 6, characterized in that: The adhesive layer (281, 382) includes a first adhesive layer (281), and the first adhesive layer (281) is arranged between the top end (247) of the working spring (242) and the adjusting bolt (243), and the first adhesive layer (281) is used to bond the top end (247) of the working spring (242) and the adjusting bolt (243).

8. The pressure sensor according to claim 7, characterized in that: The adhesive layer (281, 382) includes a second adhesive layer (382), and the second adhesive layer (382) is arranged between the tail end (248) of the working spring (242) and the magnetic core (218), and the second adhesive layer (382) is used to bond the tail end (248) of the working spring (242) and the magnetic core (218).

9. The pressure sensor according to claim 6 or 7, characterized in that: The working spring (242) is coaxially arranged with the magnetic core (218).

10. The pressure sensor according to claim 9, characterized in that: The upper shell (201) is connected to the upper part of the lower shell (202), wherein a third adhesive layer (283) is provided at the connection between the upper shell (201) and the lower shell (202).

11. The pressure sensor according to claim 9, characterized in that Also includes: Capacitors (568, 569); and A coil (251), the coil (251) being fixed to the upper housing (201), the coil (251) working in cooperation with the magnetic core (218) to form a variable inductance inductor; Wherein, the capacitor (568, 569) and the variable inductance sensor form a frequency variable oscillator.

12. The pressure sensor according to claim 11, characterized in that Also includes: at least one printed circuit board (260), the rear side of the at least one printed circuit board (260) being connected to the upper housing (201), and the end (252) of the coil (251) being connected to the at least one printed circuit board (260); The lower housing (202) is provided with a support rod (235), and the support rod (235) is used to support the front side of the at least one printed circuit board (260); Wherein, a fourth adhesive layer (584) is provided between the support rod (235) and the at least one printed circuit board (260).

13. The pressure sensor according to claim 11, wherein: The coil (251) includes at least one coil layer (654); The upper shell (201) includes a cylindrical end (240), each coil layer (654) includes a plurality of turns of wire (655), and each turn of the plurality of turns of wire (655) is wound side by side on the outer side of the cylindrical end (240) along the circumference of the cylindrical end (240); There is a fifth adhesive layer (685) extending along the axial direction of the cylindrical end (240) between at least two adjacent coil layers (654) or between at least one coil layer (654) and the cylindrical end (240).

14. The pressure sensor according to claim 13, wherein: The fifth adhesive layer (685) is disposed between the outermost coil layer (654) and the inner coil layer (654) and is used to bond the outermost coil layer (654) to the inner coil layer (654).

15. The pressure sensor according to claim 1, wherein: The working spring (242) includes several spiral coils (749), the top end (247) and the tail end (248) of the working spring (242) include at least two spiral coils (749) closely arranged side by side, and the top end (247) and / or the tail end (248) of the working spring (242) are closed structures.

16. The pressure sensor according to claim 15, characterized in that: The top end (247) and / or the tail end (248) of the working spring (242) is a closed and ground structure.

17. A pressure sensor, characterized in that include: A housing (105), the housing (105) comprising an upper housing (201) and a lower housing (202), wherein the upper housing (201) and the lower housing (202) are arranged so as to form a cavity between the upper housing (201) and the lower housing (202); A diaphragm (210), wherein the diaphragm (210) is disposed between the upper housing (201) and the lower housing (202), and divides the cavity into an upper cavity (215) and a lower cavity (216); a magnetic core (218), the magnetic core (218) being carried on the diaphragm (210); and A working spring (242), the working spring (242) comprising a top end (247) and a tail end (248), wherein the top end (247) is supported on the upper shell (201), and the tail end (248) is supported on the magnetic core (218); Wherein, at least one of the top end (247) and the tail end (248) of the working spring (242) is bonded by an adhesive process.

18. The pressure sensor according to claim 17, wherein: The diaphragm (210) comprises a support body (212) and a thin skin (213) surrounding the support body (212), wherein the thin skin (213) extends out from an edge of the support body (212); Wherein, the magnetic core (218) is carried on the support body (212).

19. The pressure sensor according to claim 18, characterized in that Also includes: A compensating elastic component (217, 318), wherein the compensating elastic component (217, 318) is sandwiched between the lower housing (202) and the diaphragm (210).

20. The pressure sensor according to claim 17, characterized in that Also includes: an adjusting bolt (243), the adjusting bolt (243) being arranged at the top of the upper shell (201), wherein the top end (247) of the working spring (242) is supported on the adjusting bolt (243), and the adjusting bolt (243) can be used to adjust the magnitude of a preset force applied by the working spring (242) to the magnetic core (218); Wherein, at least one of the top end (247) and the tail end (248) of the working spring (242) is respectively bonded to at least one of the magnetic core (218) and the adjusting bolt (243) through a gluing process.

21. The pressure sensor according to claim 1, wherein: The upper shell includes a base and a cylindrical end, and the top end of the working spring is supported to the cylindrical end of the upper shell; the working spring is a working coil spring.

22. The pressure sensor according to claim 17, wherein: The upper housing comprises a base and a cylindrical end, and the top end of the working spring is supported to the cylindrical end of the upper housing; The pressure sensor further comprises: a coil, the coil being fixed to the upper housing, the coil working in cooperation with the magnetic core to form a variable inductance inductor, wherein the coil comprises a plurality of coil layers; An adhesive layer is provided, wherein the adhesive layer is provided between at least two adjacent coil layers of the plurality of coil layers or between at least one coil layer of the plurality of coil layers and the cylindrical end portion and extends axially along the cylindrical end portion.

23. The pressure sensor according to claim 1, wherein: The upward movement of the magnetic core (218) causes the working spring (242) to be compressed.

24. The pressure sensor according to claim 17, wherein: The upward movement of the magnetic core (218) causes the working spring (242) to be compressed.

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