A pressure sensor for an automobile

Abstract

The utility model discloses a car pressure sensor in the technical field of automobile cooling system, including the base body and casing of inside pressure channel, the base body includes by the fixed platform, the sealed platform, the annular boss, the hexagon nut and the threaded connection mouth of one body connection arrangement from top to bottom, the casing sets up on the sealed platform and constitutes the sealed cavity with the fixed platform, the sealed cavity is used to accommodate the deformation diaphragm, the flexible circuit board and a plurality of strain gauges, the deformation diaphragm sets up and is located the fixed platform side surface corresponding pressure channel end, the flexible circuit board is along the casing inner wall circumferential arrangement, a plurality of strain gauges set up on the deformation diaphragm and with flexible circuit board electricity is connected, the flexible circuit board is connected with metal terminal electricity, the metal terminal outside is provided with insulating shell. The utility model discloses the flexible circuit board can be bent characteristics adaptation casing inner wall, the compression circuit volume simultaneously, the layout of circumferential encircling reduces the mechanical loss of strain transmission, and the signal stability is guaranteed.

Description

Technical Field

[0001] This utility model relates to the field of automotive cooling system technology, and in particular to a pressure sensor for automobiles. Background Technology

[0002] Against the backdrop of the automotive industry's electrification, intelligentization, and lightweighting upgrades, pressure sensors, as key sensing components of the cooling system, need to operate stably for extended periods under complex conditions of extreme vibration, confined spaces, and strong electromagnetic interference.

[0003] In existing technologies, automotive pressure sensors commonly use rigid printed circuit boards (PCBs) to carry strain gauge signal processing circuits. Rigid PCBs are typically thicker than 0.8mm, and due to their straight-plate structure, they require soldering for fixation. However, this design has several drawbacks: within the irregularly shaped cavity of the sensor, the rigid board is difficult to conform to the inner wall contour, resulting in wasted effective wiring area; the mechanical connection between the rigid PCB and the substrate is a rigid contact, which easily leads to stress concentration at solder joints and pins under vibration loads, causing the pressure sensor to be prone to damage or fatigue, resulting in low vibration resistance and reliability. Utility Model Content

[0004] To address the shortcomings of existing technologies, this invention provides a pressure sensor for automobiles. By utilizing its bendable properties to adapt to the inner wall of the housing, the circuit volume is reduced while the circumferential layout minimizes mechanical losses in strain transmission and ensures signal stability.

[0005] The purpose of this utility model is achieved as follows: A pressure sensor for automobiles includes a base and a housing with an internal pressure channel. The base includes a fixed platform, a sealing platform, an annular boss, a hexagonal nut, and a threaded connection port integrally connected from top to bottom. The housing is disposed on the sealing platform and forms a sealed cavity with the fixed platform. The sealed cavity is used to accommodate a deformation diaphragm, a flexible circuit board, and several strain gauges. The deformation diaphragm is disposed at the end of the pressure channel and located on the side of the fixed platform. The flexible circuit board is disposed circumferentially along the inner wall of the housing. Several strain gauges are disposed on the deformation diaphragm and electrically connected to the flexible circuit board. The flexible circuit board is electrically connected to a metal terminal, and an insulating shell is disposed on the outside of the metal terminal.

[0006] In use, when the pressure medium of the automotive system flows into the pressure channel of the substrate through the threaded connection, the pressure acts on the deformation diaphragm located at the end of the pressure channel, causing the diaphragm to deform. The strain gauge attached to the deformation diaphragm changes resistance as the diaphragm deforms. A flexible circuit board arranged circumferentially along the inner wall of the housing collects this resistance change in real time and converts it into an electrical signal. The electrical signal is transmitted to the metal terminal via the flexible circuit board, and finally, the metal terminal outputs an electrical signal corresponding to the pressure, thereby realizing pressure detection. Compared with the prior art, the advantages of this invention are: utilizing the three-dimensional curved surface of the inner wall of the housing and the flexibility of the flexible circuit board itself to conform to the cavity contour, the originally idle side wall space is transformed into an effective wiring area, improving space utilization; the flexibility of the flexible circuit board allows it to conformally fix with the housing, and under vibration load, stress is evenly distributed throughout the circumference through the flexible structure, rather than concentrated on a single solder point / pin, improving vibration resistance reliability.

[0007] As a further improvement of this utility model, the strain gauge is a silicon strain gauge.

[0008] As a further improvement of this utility model, the number of silicon strain gauges is four, and the four silicon strain gauges are connected by metal wires to form a Wheatstone bridge.

[0009] As a further improvement of this utility model, the silicon strain gauge is integrated with the deformation diaphragm through a glass micro-melting process.

[0010] As a further improvement of this utility model, an annular groove is provided on the upper side of the sealing platform, and the bottom of the housing extends into the annular groove.

[0011] As a further improvement of this utility model, the sealing platform, the annular boss, the hexagonal nut and the threaded connection are on the same axis as the pressure channel, the fixed platform is eccentrically set with respect to the central axis of the pressure channel, and the deformable diaphragm is located on the side closer to the pressure channel.

[0012] As a further improvement of this utility model, both the substrate and the deformable diaphragm are made of metallic materials.

[0013] As a further improvement of this utility model, the shell is made of plastic material.

[0014] As a further improvement of this utility model, the flexible circuit board is bonded to the inner wall of the housing with epoxy adhesive. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0016] Figure 1 This is the front view of the present invention.

[0017] Figure 2 This is a top view of the present invention.

[0018] Figure 3 for Figure 2 Sectional view at point AA.

[0019] Among them, 1 is the base, 101 is the fixed platform, 102 is the sealing platform, 103 is the annular boss, 104 is the hexagonal nut, 105 is the threaded connection port, 106 is the annular groove, 2 is the shell, 3 is the sealing cavity, 4 is the deformable diaphragm, 5 is the flexible circuit board, 6 is the strain gauge, 7 is the metal terminal, 8 is the insulating shell, and 9 is the pressure channel. Detailed Implementation

[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0021] like Figure 1-3 The pressure sensor for automobiles shown includes a base 1 with an internal pressure channel 9 and a plastic housing 2. The base 1 includes a fixed platform 101, a sealing platform 102, an annular boss 103, a hexagonal nut 104, and a threaded connection port 105 integrally connected from top to bottom. The housing 2 is fixedly connected to the sealing platform 102 and forms a sealed cavity 3 with the fixed platform 101. The sealed cavity 3 is used to accommodate a deformation diaphragm 4, a flexible circuit board 5, and four strain gauges 6. The deformation diaphragm 4 is disposed at the end of the pressure channel 9 and located on the side of the fixed platform 101. The flexible circuit board 5 is bonded to the inner wall of the housing 2 with epoxy adhesive and arranged circumferentially along the inner wall of the housing 2. The four strain gauges 6 are disposed on the deformation diaphragm 4 and electrically connected to the flexible circuit board 5 through metal wires. The flexible circuit board 5 is electrically connected to a metal terminal 7, and an insulating shell 8 is disposed on the outside of the metal terminal 7.

[0022] In this embodiment, the strain gauge 6 is a silicon strain gauge 6, and four silicon strain gauges 6 are connected by metal wires to form a Wheatstone bridge; the substrate 1 is made of a rigid material (such as stainless steel) to ensure the rigidity of the sensor body, and the deformation diaphragm 4 is made of 316L stainless steel, which can resist high-frequency vibration fatigue under pressure deformation.

[0023] The silicon strain gauge 6 is integrated with the deformation diaphragm 4 through a glass micro-melting process. The glass layer is melted at high temperature to form a metallurgical bond with the silicon and metal diaphragm. Under automotive vibration conditions, there is no relative displacement between the strain gauge 6 and the diaphragm, avoiding the phenomenon of "strain transfer failure" or "solder joint detachment". In addition, the glass micro-melting layer itself is an inorganic material, which is resistant to oil and salt water corrosion, and can avoid the failure of strain gauge 6 caused by the aging and cracking of traditional epoxy resin, thereby extending the sensor life.

[0024] An annular groove 106 is formed on the upper side of the sealing platform 102. A sealing element is disposed within the annular groove 106. A snap fastener is provided at the bottom of the housing 2, which can extend into the annular groove 106 and fit tightly with the sealing element. The sealing element undergoes elastic deformation under compression, filling the microscopic gaps. The annular groove 106 serves as an insertion positioning reference. When the bottom of the housing 2 slides into the groove along its inner wall, the geometric contour of the groove forces the housing 2 to automatically align with the sealing platform 102, ensuring spatial alignment of internal components such as the flexible circuit board 5 and metal terminals 7, and reducing signal transmission interference.

[0025] The sealing platform 102, the annular boss 103, the hexagonal nut 104, and the threaded connection port 105 are on the same axis as the pressure channel 9. The fixed platform 101 is eccentrically set to the central axis of the pressure channel 9. The deformable diaphragm 4 is located on the side close to the pressure channel 9. The pressure medium reaches the deformable diaphragm 4 directly along the axis, avoiding turbulence loss and pressure attenuation caused by radial flow. The pressure transmission efficiency is high and the detection response speed is fast.

[0026] In use, the threaded connection 105 quickly engages with the automotive pipeline / component, and the hexagonal nut 104 provides tightening force, achieving "ready to use immediately." The annular boss 103 serves as a positioning reference, ensuring the coaxiality of the sensor and pipeline, reducing installation errors. Simultaneously, as a load-bearing structure, it disperses the axial force of the threaded connection, preventing deformation of the sealing platform 102 or the fixed platform 101 due to uneven stress. The advantages of this invention are: the sealing platform 102 is tightly connected to the housing 2 to form a static sealing surface, preventing external oil, water, and gas from intruding into the sealing cavity 3; the engagement and locking of the hexagonal nut 104 with the threaded connection 105 further compresses the sealing pair, enhancing sealing stability under dynamic operating conditions; the metal terminal 7 enables a highly reliable connection to the external circuit, and the insulating shell 8 encloses the terminal to form an electromagnetic shielding layer, blocking interference from external strong electromagnetic sources and ensuring stable transmission of the weak signal from the strain gauge 6.

[0027] The above description of the embodiments is only for the purpose of helping to understand the method and core idea of ​​this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made to this utility model without departing from the principle of this utility model, and these improvements and modifications also fall within the protection scope of the claims of this utility model.

Claims

1. A pressure sensor for automobiles, comprising a base and a housing with an internal pressure channel, characterized in that, The substrate includes a fixed platform, a sealing platform, an annular boss, a hexagonal nut, and a threaded connection port integrally connected from top to bottom. The housing is disposed on the sealing platform and forms a sealed cavity with the fixed platform. The sealed cavity is used to accommodate a deformation diaphragm, a flexible circuit board, and several strain gauges. The deformation diaphragm is disposed at the end of the pressure channel and located on the side of the fixed platform. The flexible circuit board is disposed circumferentially along the inner wall of the housing. Several strain gauges are disposed on the deformation diaphragm and electrically connected to the flexible circuit board. The flexible circuit board is electrically connected to a metal terminal, and an insulating shell is disposed on the outside of the metal terminal.

2. The pressure sensor for automobiles according to claim 1, characterized in that, The strain gauge is a silicon strain gauge.

3. A pressure sensor for automobiles according to claim 2, characterized in that, The number of silicon strain gauges is four, and the four silicon strain gauges are connected by metal wires to form a Wheatstone bridge.

4. A pressure sensor for automobiles according to claim 2, characterized in that, The silicon strain gauge is integrated with the deformation diaphragm through a glass micro-melting process.

5. A pressure sensor for automobiles according to claim 1, characterized in that, An annular groove is provided on the upper side of the sealing platform, and the bottom of the housing extends into the annular groove.

6. A pressure sensor for automobiles according to claim 1, characterized in that, The sealing platform, annular boss, hexagonal nut, and threaded connection are on the same axis as the pressure channel. The fixed platform is eccentrically set to the central axis of the pressure channel. The deformable diaphragm is located on the side closer to the pressure channel.

7. A pressure sensor for automobiles according to claim 1, characterized in that, Both the substrate and the deformable membrane are made of metallic materials.

8. A pressure sensor for automobiles according to claim 1, characterized in that, The shell is made of plastic material.

9. A pressure sensor for automobiles according to claim 1, characterized in that, The flexible circuit board is bonded to the inner wall of the housing with epoxy adhesive.

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