Piezoresistive MEMS pressure sensor for gearbox

Abstract

The invention discloses a piezoresistive MEMS pressure sensor for a gearbox, and relates to the technical field of pressure sensors for passenger car gearbox clutch systems, the piezoresistive MEMS pressure sensor comprises a connector, a base and a shell which are connected in sequence, and a ceramic circuit assembly is installed in a cavity formed by the connector and the base in a matched mode. A piezoresistive MEMS pressure chip used for detecting oil pressure is installed on the ceramic circuit assembly, a through hole used for containing the piezoresistive MEMS pressure chip is formed in the base, and an oil passing hole corresponding to the piezoresistive MEMS pressure chip in position is formed in the shell. According to the invention, the piezoresistive MEMS pressure chip is applied to the field of passenger car gearbox oil pressure measurement for the first time, and the manufacturing cost of the gearbox oil pressure sensor is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of pressure sensors for a passenger car transmission clutch system, and in particular to a piezoresistive MEMS pressure sensor for a transmission. Background Art

[0002] The commonly used transmission oil pressure sensor is a capacitive pressure sensor. The principle is that when the oil pressure in the transmission changes, the distance between the positive and negative electrodes of the capacitor inside the capacitive pressure sensor will change, thereby changing the capacitance value. Since the fluid in the transmission clutch system has the characteristics of high temperature and strong corrosiveness, the pressure sensitive unit of the existing capacitive pressure sensor is often protected by sputtering film or glass micro-melting technology, resulting in high manufacturing costs for existing capacitive pressure sensors for transmissions.

[0003] Therefore, how to provide a transmission oil pressure sensor that is resistant to high temperature and corrosion and has low manufacturing cost has become a difficult problem that needs to be solved urgently by those skilled in the art. Summary of the invention

[0004] The purpose of the present invention is to provide a piezoresistive MEMS pressure sensor for a gearbox, so as to solve the problem of high manufacturing cost of existing capacitive pressure sensors.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] The present invention provides a piezoresistive MEMS pressure sensor for a gearbox, comprising a connector, a base and a shell connected in sequence, a ceramic circuit component is installed in a chamber formed by the connector and the base, a piezoresistive MEMS pressure chip for detecting oil pressure is installed on the ceramic circuit component, a through hole for placing the piezoresistive MEMS pressure chip is provided on the base, and an oil through hole corresponding to the position of the piezoresistive MEMS pressure chip is opened on the shell.

[0007] Optionally, the connector and the base are snap-connected, and snap-on positions are symmetrically arranged on both sides of the bottom of the connector.

[0008] Optionally, snap-on inserts are symmetrically arranged at both ends of the base, the snap-on inserts correspond to the snap-on buckle positions, the through hole is arranged at the center of the base, a special-shaped gasket for sealing is arranged around the through hole, and the ceramic circuit assembly is placed on the special-shaped gasket.

[0009] Optionally, the base and the shell are connected by riveting, and mounting protrusions and mounting recesses for limiting are respectively provided on facing surfaces of the base and the shell, and a grounding hole is also installed on the base.

[0010] Optionally, the oil passage hole is provided at the center of the housing.

[0011] Optionally, the ceramic circuit component includes a ceramic circuit substrate which is placed on the special-shaped washer. A first elastic sheet, a signal conditioning chip and resistive-capacitive electronic components are respectively mounted on the top surface of the ceramic circuit substrate. The piezoresistive MEMS pressure chip is soldered to the center of the bottom of the ceramic circuit substrate through solder balls, and a second elastic sheet is also mounted at the bottom of the ceramic circuit substrate;

[0012] The piezoresistive MEMS pressure chip is electrically connected through the ceramic circuit substrate and the signal conditioning chip, and the signal conditioning chip is electrically connected to the resistive-capacitive electronic components and the first elastic sheet in sequence through the ceramic circuit substrate;

[0013] The first elastic sheet is electrically connected to the connector; the second elastic sheet passes through the grounding hole position and is electrically connected to the housing.

[0014] Optionally, a high-temperature and corrosion-resistant protective glue is coated around the piezoresistive MEMS pressure chip.

[0015] Optionally, a threaded post for connecting to the gearbox is integrally formed at the center of the bottom of the housing, and an O-ring for sealing is provided at the threaded end of the threaded post.

[0016] Optionally, a wiring jack is provided at the top of the connector.

[0017] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0018] 1) The present invention first applies the piezoresistive MEMS pressure chip in the field of oil pressure measurement of passenger car gearboxes, reducing the manufacturing cost of gearbox oil pressure sensors.

[0019] 2) By coating a high-temperature and corrosion-resistant protective glue around the piezoresistive MEMS pressure chip, the piezoresistive MEMS pressure chip can be applicable to high-temperature and highly corrosive environments, improving the service life of the piezoresistive MEMS pressure chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention will be further described below in conjunction with the drawings.

[0021] Figure 1 It is an exploded structural schematic diagram of the piezoresistive MEMS pressure sensor for the gearbox of the present invention;

[0022] Figure 2 It is a front view of the piezoresistive MEMS pressure sensor for the gearbox of the present invention;

[0023] Figure 3Explosion structure schematic diagram of the ceramic circuit component of the present invention;

[0024] Figure 4 Top view of the ceramic circuit component of the present invention;

[0025] Figure 5 Bottom view of the ceramic circuit component of the present invention;

[0026] Figure 6 Structure schematic diagram of the piezoresistive MEMS pressure chip of the present invention;

[0027] Figure 7 Structure schematic diagram of the ceramic circuit component of the present invention;

[0028] Figure 8 Top view of the base of the present invention;

[0029] Figure 9 Schematic diagram of the connection relationship between the base and the ceramic circuit component of the present invention;

[0030] Figure 10 Top view of the connector of the present invention;

[0031] Figure 11 Structure schematic diagram of the connector of the present invention;

[0032] Figure 12 Schematic diagram of the connection relationship between the connector and the base of the present invention;

[0033] Figure 13 Top view of the housing of the present invention;

[0034] Figure 14 Structure schematic diagram of the housing of the present invention.

[0035] Explanation of reference numerals: 1. Connector; 2. Base; 3. Housing; 4. Ceramic circuit component;

[0036] 11. Snap buckle position;

[0037] 21. Through hole; 22. Snap buckle insertion bone; 23. Special-shaped washer; 24. Mounting bump; 25. Grounding hole position;

[0038] 31. Oil passage hole; 32. Mounting concave point; 33. O-ring.

[0039] 41. Piezoresistive MEMS pressure chip; 42. Ceramic circuit substrate; 43. First elastic sheet; 44. Signal conditioning chip; 45. Resistive-capacitive electronic components; 46. Second elastic sheet; 47. Protective glue; 48. Solder ball. Detailed implementation manners

[0040] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clear and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0041] As Figures 1-14 shown, a piezoresistive MEMS pressure sensor for a gearbox includes a connector 1, a base 2 and a housing 3 connected in sequence. A ceramic circuit component 4 is installed in the chamber formed by the cooperation of the connector 1 and the base 2. A piezoresistive MEMS pressure chip 41 for detecting oil pressure is installed on the ceramic circuit component 4. A through hole 21 for placing the piezoresistive MEMS pressure chip 41 is provided on the base 2. An oil through hole 31 corresponding to the position of the piezoresistive MEMS pressure chip 41 is provided on the housing 3.

[0042] Specifically, the connector 1 and the base 2 are connected by a snap connection. Snap fastener positions 11 are symmetrically provided on both sides of the bottom of the connector 1.

[0043] Specifically, snap insertion bones 22 are symmetrically provided at both ends of the base 2. The snap insertion bones 22 correspond to the snap fastener positions 11. The through hole 21 is provided at the center of the base 2. A special-shaped gasket 23 for sealing is provided around the through hole 21. The ceramic circuit component 4 is placed on the special-shaped gasket 23.

[0044] Specifically, the base 2 and the housing 3 are connected by press riveting. Mounting bumps 24 for limiting are respectively provided on the opposite surfaces of the base 2 and the housing 3. A grounding hole position 25 is also installed on the base 2.

[0045] Specifically, the oil through hole 31 is provided at the center of the housing 3.

[0046] Specifically, the ceramic circuit component 4 includes a ceramic circuit substrate 42. The ceramic circuit substrate 42 is placed on the special-shaped gasket 23. A first elastic sheet 43, a signal conditioning chip 44 and resistive-capacitive electronic components 45 are respectively installed on the top surface of the ceramic circuit substrate 42. The piezoresistive MEMS pressure chip 41 is welded to the center of the bottom of the ceramic circuit substrate 42 by solder balls 48. A second elastic sheet 46 is also installed at the bottom of the ceramic circuit substrate 42;

[0047] The piezoresistive MEMS pressure chip 41 is electrically connected to the signal conditioning chip 44 through the ceramic circuit substrate 42. The signal conditioning chip 44 is electrically connected to the resistive-capacitive electronic components 45 and the first elastic sheet 43 in sequence through the ceramic circuit substrate 42;

[0048] The first elastic piece 43 is electrically connected to the connector 1; the second elastic piece 46 is electrically connected to the housing 3 after passing through the grounding hole 25.

[0049] Wherein, the signal conditioning chip 44 amplifies and compensates the electrical signal output by the piezoresistive MEMS pressure chip 41.

[0050] Specifically, a protective glue 47 with high temperature and corrosion resistance is coated around the piezoresistive MEMS pressure chip 41.

[0051] During specific implementation, the piezoresistive MEMS pressure chip 41 is protected by the protective glue through a dispensing process.

[0052] Specifically, a threaded post for connecting to the transmission is integrally formed at the center of the bottom of the housing 3, and an O-ring 33 for sealing is provided at the threaded end of the threaded post.

[0053] Specifically, a wiring jack is provided at the top of the connector 1. The connector 1 is electrically connected to the passenger car controller through the wiring jack.

[0054] The installation process of the present invention is as follows:

[0055] First, place the special-shaped washer 23 at the through hole 21 on the base 2. Secondly, after aligning the second elastic piece 46 on the ceramic circuit assembly 4 with the grounding hole 25 on the base 2, place the ceramic circuit assembly 4 on the special-shaped washer 23.

[0056] Then, snap-connect the base 2 to the bottom end of the connector 1. Finally, after aligning the installation bumps 24 on the base 2 with the installation dimples 32 on the housing 3, press-rivet the housing 3 to the base 2 to complete the installation of the piezoresistive MEMS pressure sensor for the transmission.

[0057] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or elements inherent to such process, method, article or device.

[0058] The embodiments described above are only descriptions of the preferred modes of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A piezoresistive MEMS pressure sensor for a gearbox, characterized in that: The invention comprises a connector (1), a base (2) and a shell (3) which are connected in sequence; a ceramic circuit assembly (4) is installed in a chamber formed by the cooperation of the connector (1) and the base (2); a piezoresistive MEMS pressure chip (41) for detecting oil pressure is installed on the ceramic circuit assembly (4); a through hole (21) for placing the piezoresistive MEMS pressure chip (41) is provided on the base (2); and an oil through hole (31) corresponding to the position of the piezoresistive MEMS pressure chip (41) is provided on the shell (3).

2. The piezoresistive MEMS pressure sensor for a gearbox according to claim 1, characterized in that: The connector (1) and the base (2) are connected by snapping, and snapping positions (11) are symmetrically arranged on both sides of the bottom of the connector (1).

3. The piezoresistive MEMS pressure sensor for a gearbox according to claim 2, characterized in that: Snap-on inserts (22) are symmetrically arranged at both ends of the base (2), the snap-on inserts (22) correspond to the snap-on buckle positions (11), the through hole (21) is arranged at the center of the base (2), a special-shaped gasket (23) for sealing is arranged around the through hole (21), and the ceramic circuit component (4) is placed on the special-shaped gasket (23).

4. The piezoresistive MEMS pressure sensor for a gearbox according to claim 3, characterized in that: The base (2) and the shell (3) are connected by riveting, and mounting protrusions (24) and mounting recesses (32) for limiting are respectively arranged on the facing surfaces of the base (2) and the shell (3), and a grounding hole (25) is also installed on the base (2).

5. The piezoresistive MEMS pressure sensor for a gearbox according to claim 4, characterized in that: The oil through hole (31) is arranged at the center of the housing (3).

6. The piezoresistive MEMS pressure sensor for a gearbox according to claim 5, characterized in that: The ceramic circuit assembly (4) comprises a ceramic circuit substrate (42), the ceramic circuit substrate (42) is placed on the special-shaped gasket (23), a first spring sheet (43), a signal adjustment chip (44) and a resistor-capacitor type electronic component (45) are respectively mounted on the top surface of the ceramic circuit substrate (42), the piezoresistive MEMS pressure chip (41) is welded to the bottom center of the ceramic circuit substrate (42) via a solder ball (48), and a second spring sheet (46) is also mounted on the bottom of the ceramic circuit substrate (42); The piezoresistive MEMS pressure chip (41) is electrically connected to the signal adjustment chip (44) via the ceramic circuit substrate (42); the signal adjustment chip (44) is electrically connected to the resistor-capacitor electronic component (45) and the first spring sheet (43) in sequence via the ceramic circuit substrate (42); The first spring piece (43) is electrically connected to the connector (1); and the second spring piece (46) is electrically connected to the housing (3) after passing through the grounding hole (25).

7. The piezoresistive MEMS pressure sensor for a gearbox according to claim 6, characterized in that: The piezoresistive MEMS pressure chip (41) is coated with a high temperature resistant and corrosion resistant protective glue (47) around it.

8. The piezoresistive MEMS pressure sensor for a gearbox according to claim 1, characterized in that: A threaded column for connecting to a gearbox is integrally formed at the bottom center of the housing (3), and an O-ring (33) for sealing is provided at the threaded end of the threaded column.

9. The piezoresistive MEMS pressure sensor for a gearbox according to claim 1, characterized in that: The top of the connector (1) is provided with a wiring jack.

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