Patent Publication Number: US-2023135371-A1

Title: Sealing Pin, Pressure Detention Module and Pressure Sensor

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of the filing date under 35 U.S.C. § 119(a)-(d) of Chinese Patent Application No. 202111299135.9, filed on Nov. 4, 2021. 
     FIELD OF THE INVENTION 
     The present invention relates to a sealing pin, a pressure detection module including the sealing pin and a pressure sensor including the pressure detection module. 
     BACKGROUND 
     A pressure sensor usually includes a main body, a diaphragm, and a pressure detection chip. An oil filled cavity is formed in the main body, and the external media pressure applied to the diaphragm can be transmitted to the pressure detection chip through the oil in the oil filled cavity. Therefore, the pressure detection chip can detect the external media pressure applied to the diaphragm. 
     In the prior art, after the oil filling cavity is filled with oil, the oil filling port of the oil filling cavity needs to be sealed with a ball to prevent oil leakage. The existing technical scheme requires filling the whole oil filling cavity with oil, which deteriorates the temperature characteristics of the pressure sensor and reduces the detection accuracy of the pressure sensor. 
     SUMMARY 
     A sealing pin includes a body part and an end part connected to the body part. The body part is insertable into a liquid filling path of a pressure sensor. The body part has a groove on an outer surface. The end part seals a liquid filling port of the liquid filling path. When the sealing pin is inserted into the liquid filling path, an external media pressure applied to a diaphragm of the pressure sensor is transmitted to a pressure detection chip of the pressure sensor through a liquid in the groove. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The features of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the accompanying drawings, in which: 
         FIG.  1    is a perspective view of a pressure sensor according to an embodiment; 
         FIG.  2    is an exploded perspective view of the pressure sensor; 
         FIG.  3    is an axial sectional view of the pressure sensor; 
         FIG.  4    is an axial sectional view of the pressure sensor without a sealing pin; 
         FIG.  5    is a perspective view of a sealing pin according to an embodiment; 
         FIG.  6    is a plan view of the sealing pin; and 
         FIG.  7    is a perspective view of a sealing pin according to another embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Exemplary embodiments of the present disclosure will be described hereinafter in detail with reference to the attached drawings, wherein like reference numerals refer to like elements. The present disclosure may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein; rather, these embodiments are provided so that the present disclosure will convey the concept of the disclosure to those skilled in the art. 
     In the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. It will be apparent, however, that one or more embodiments may be practiced without these specific details. In other instances, well-known structures and devices are schematically shown in order to simplify the drawing. 
     A pressure sensor according to an embodiment, as shown in  FIG.  1    and  FIG.  2   , includes a housing  70  and a pressure detection module. The pressure detection module is installed in housing  70 . 
     As shown in  FIGS.  1  to  4   , in the illustrated embodiment, the pressure detection module includes: a main body  10 , a sealing pin  20 , a pressure detection chip  30 , and a diaphragm  1 . A liquid filling cavity  11 ,  12 ,  13  for filling liquid is formed in the main body  10 . The liquid filling cavity  11 ,  12 ,  13  includes a liquid filling path  13 . The diaphragm  1  is attached to the main body  10  for transmitting an external media pressure to the liquid in the liquid filling cavity  11 ,  12 ,  13 . The pressure detection chip  30  is installed on the main body  10  to detect the liquid pressure in the liquid filling cavity  11 ,  12 ,  13 . The sealing pin  20  is inserted into the liquid filling path  13  and seals the liquid filling port  13   a  of the liquid filling path  13 . 
     The sealing pin  20 , as shown in  FIGS.  3 ,  5 , and  6   , includes a body part  21  and an end part  22 . The body part  21  of the sealing pin  20  is inserted into the liquid filling path  13  of the pressure sensor, and a groove  210  is formed on the outer surface of the body part  21 . The end part  22  of the sealing pin  20  is connected to the body part  21  for sealing the liquid filling port  13   a  of the liquid filling path  13 . 
     When the sealing pin  20  is inserted into the liquid filling path  13 , as shown in  FIGS.  2  and  3   , the external media pressure applied to the diaphragm  1  of the pressure sensor can be transmitted to the pressure detection chip  30  of the pressure sensor through the liquid in the groove  210 . The liquid filled in the liquid filling path  13  includes but is not limited to oil. 
     In the illustrated embodiment, the groove  210  on the sealing pin  20  is a spiral groove extending along the spiral path. However, the present invention is not limited to this, and the groove  210  may also have other suitable shapes. In the embodiments shown in  FIGS.  3 ,  5 , and  6   , a single spiral groove is formed on the body part  21  of the sealing pin  20 . However, the present invention is not limited to this, and a plurality of helical grooves separated from each other may be formed on the body part  21  of the sealing pin  20 . 
     As shown in  FIGS.  5  and  6   , in the illustrated embodiment, the body part  21  has a root adjacent to the end part  22  and an end opposite to the end part  22 . The groove  210  extends from the root of the body part  21  to the end of the body part  21 . The groove  210  has an inlet  210   a  located at the root of the body part  21  and an outlet  210   b  located at the end of the body part  21 . In the shown embodiment, the liquid filled from the liquid filling port  13   a  of the liquid filling path  13  can flow to the entire liquid filling cavity  11 ,  12 ,  13  of the pressure sensor through the groove  210  of the sealing pin  20 . 
     In the illustrated embodiment, the body part  21  of the sealing pin  20  is cylindrical, and the outer diameter of the body part  21  is set to be equal to or slightly smaller than the inner diameter of the liquid filling path  13 . 
     As shown in the embodiment of  FIGS.  5  and  6   , the sealing pin  20  also includes a neck  23  connected between the body part  21  and the end part  22 . In the illustrated embodiment, the body part  21  and the neck  23  of the sealing pin  20  are cylindrical, and the outer diameter of the neck  23  is smaller than that of the body part  21 . 
     As shown in  FIGS.  3 ,  5 , and  6   , in the illustrated embodiment, the end part  22  of the sealing pin  20  has a conical sealing surface  22   a , which is welded to the inner peripheral wall of the liquid filling port  13   a  of the liquid filling path  13  to seal the liquid filling port  13   a  of the liquid filling path  13 . In the illustrated embodiment, after filling the liquid, the end part  22  of the sealing pin  20  is welded to the inner peripheral wall of the liquid filling port  13   a  of the liquid filling path  13 , thereby sealing the liquid filling port  13   a  of the liquid filling path  13  to prevent liquid leakage during use. 
     In an embodiment, a pressure detection module is disclosed. The pressure detection module includes a main body  10 , a diaphragm  1 , a pressure detection chip  30  and the sealing pin  20 . A liquid filling cavity  11 ,  12  and  13  for liquid filling is formed in the main body  10 . The liquid filling cavity  11 ,  12  and  13  includes a liquid filling path  13 . The diaphragm  1  is attached to the main body  10  and is used to transmit an external media pressure to the liquid in the liquid filling cavity  11 ,  12  and  13 . The pressure detection chip  30  is installed on the main body  10  to detect the liquid pressure in the liquid filling cavity  11 ,  12  and  13 . The sealing pin  20  is inserted into the liquid filling path  13  and seals the liquid filling port  13   a  of the liquid filling path  13 . 
     As shown in  FIG.  4   , the liquid filling cavity  11 ,  12  and  13  in the main body  10  also includes a first chamber  11  and a second chamber  12  communicating with the liquid filling path  13 . The diaphragm  1  is attached to the opening of the first chamber  11  of the main body  10  to seal the opening of the first chamber  11 , and the pressure detection chip  30  is installed on the opening of the second chamber  12  of the main body  10  to seal the opening of the second chamber  12 . The first chamber  11  and the second chamber  12  of the main body  10  are connected with each other through the groove  210  on the sealing pin  20 , so that the external media pressure applied to the diaphragm  1  can be transmitted to the pressure detection chip  30  through the liquid in the groove  210 . 
     In the shown embodiment, the liquid filling port  13   a  of the liquid filling path  13  is connected with the first chamber  11  and the second chamber  12  through the groove  210  on the sealing pin  20 , so that the liquid filled from the liquid filling port  13   a  of the liquid filling path  13  can flow through the groove  210  to the entire liquid filling cavity  11 ,  12 ,  13  of the pressure sensor. 
     In an embodiment, a pressure sensor is disclosed. The pressure sensor comprises a housing  70  and the aforementioned pressure detection module, which is partially received in the housing  70 . 
     The main body  10  of the pressure detection module includes a base part  10   b  and an installation part  10   a , as shown in  FIGS.  2  and  3   . The base part  10   b  is located outside the housing  70  and attached to one end of the housing  70 . The installation part  10   a  is connected to the top surface of the base part  10   b  and is accommodated inside the housing  70 . The pressure detection chip  30  of the pressure detection module is installed on the installation part  10   a , and the diaphragm  1  of the pressure detection module is attached to the bottom surface of the base part  10   b.    
     As shown in  FIG.  4   , the liquid filling port  13   a  of the liquid filling path  13  of the pressure detection module is formed on an end surface of the installation part  10   a , and the pressure detection chip  30  is mounted on a side surface of the installation part  10   a.    
     As shown in  FIGS.  2  and  3   , in the illustrated embodiment, the pressure sensor also includes a circuit board  40 , which is mounted on the installation part  10   a  of the main body  10  and electrically connected with the pressure detection chip  30 . 
     As shown in  FIGS.  1 - 3   , the pressure sensor also includes an end cover  80  and a plurality of connection terminals  50 . The end cover  80  is installed on the opening formed on the other end of the housing  70 . The connection terminals  50  are fixed to the end cover  80 . The connection terminals  50  pass through the end cover  80  and are electrically connected to the circuit board  40 . 
     In an embodiment, as shown in  FIGS.  2  and  3   , the pressure sensor also includes a flexible flat cable  60  for electrically connecting the circuit board  40  to the connection terminals  50 . 
     A sealing pin  20  according to another embodiment is shown in  FIG.  7   . The difference between the sealing pin  20  shown in  FIG.  7    and the sealing pin  20  shown in  FIGS.  1 - 6    lies only in the shape of the groove  210 . In the embodiment shown in  FIG.  7   , at least one groove  210  is formed on the outer surface of the body part  21  of the sealing pin  20 , and the groove  210  extends along a straight line parallel to the axis of the sealing pin  20 . As shown in  FIG.  7   , a plurality of grooves  210  extending linearly are formed on the outer surface of the body part  21  of the sealing pin  20 , and the grooves  210  are evenly spaced around the circumference of the body part  21  of the sealing pin  20 . 
     In the foregoing exemplary embodiments according to the present invention, the sealing pin  20  is inserted into the liquid filling path  13  of the liquid filling cavity  11 ,  12 ,  13 , so that the liquid filling amount can be reduced, the temperature characteristics of the pressure sensor can be improved, and the detection accuracy of the pressure sensor can be greatly improved. 
     It should be appreciated for those skilled in this art that the above embodiments are intended to be illustrative, and not restrictive. For example, many modifications may be made to the above embodiments by those skilled in this art, and various features described in different embodiments may be freely combined with each other without conflicting in configuration or principle. 
     Although several exemplary embodiments have been shown and described, it would be appreciated by those skilled in the art that various changes or modifications may be made in these embodiments without departing from the principles and spirit of the disclosure, the scope of which is defined in the claims and their equivalents. 
     As used herein, an element recited in the singular and proceeded with the word “a” or “an” should be understood as not excluding plural of said elements or steps, unless such exclusion is explicitly stated. Furthermore, references to “one embodiment” of the present invention are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. Moreover, unless explicitly stated to the contrary, embodiments “comprising” or “having” an element or a plurality of elements having a particular property may include additional such elements not having that property.