JP4747866B2 - Temperature sensor mounting structure for high-pressure hydrogen containers - Google Patents

Description

  The present invention relates to a temperature sensor mounting structure for measuring the temperature inside a high-pressure vessel in which a high-pressure fluid is sealed, and is particularly suitable for a temperature sensor mounting structure for a high-pressure hydrogen vessel for hydrogen storage in a fuel cell vehicle. It is a thing.

  As a high-pressure container, for example, a high-pressure hydrogen container for hydrogen storage of a fuel cell vehicle has a stainless steel boss at both ends, as shown in FIG. 2 of Non-Patent Document 1, and a resin liner formed by injection molding. A high-pressure hydrogen container is known which is formed by wrapping carbon fiber reinforced plastic (CFRP), reinforced with glass fiber reinforced plastic (GFRP), and attached with an impact absorbing pad. An opening provided in the boss is closed by a stainless steel boss end, and one of the boss ends is provided with a valve for filling and discharging hydrogen.

  Since the high-pressure hydrogen container is used at an extremely high pressure of about 35 MPa to 70 MPa as the hydrogen filling pressure, 105 MPa is defined as a pressure-guaranteed value as a 1.5-fold pressure resistance to ensure safety, and the use environment is −40 It is supposed to be able to withstand a temperature range of ˜85 ° C. (For example, see Non-Patent Document 1 and Non-Patent Document 2 below).

  Further, the temperature of the hydrogen gas in the high-pressure hydrogen container rises by compression when filling with hydrogen, and falls by decompression when consuming hydrogen. Therefore, using the gas equation of state from the pressure and temperature of the hydrogen gas, the optimal filling amount and accurate consumption amount are calculated, and the high-pressure hydrogen container is filled with hydrogen gas in a safer and faster manner. In order to perform more accurate fuel consumption control, it is necessary to more accurately measure the hydrogen gas pressure and the hydrogen gas temperature inside the high-pressure hydrogen container (for example, see Non-Patent Documents 2 and 3 below). ).

  On the other hand, as shown in FIG. 1 of Patent Document 1, the temperature sensor 10 includes a housing 12 having a hexagonal thick portion 14 that can be easily tightened with a spanner or the like. Are fastened and fixed by screwing a female screw 83 provided in the cylinder portion 82 of the high-pressure vessel and a male screw 36 provided in the housing 12 of the temperature sensor 10.

  However, when measuring the temperature in a high-pressure vessel such as a high-pressure hydrogen vessel for a fuel cell vehicle, as shown in FIG. 1 of Patent Document 1, the female screw 83 provided in the cylinder portion 82 of the high-pressure vessel is used. Even if the temperature sensor 10 including the housing 12 provided with the male screw 36 screwed to the female screw 83 is attached from the outside of the high-pressure vessel, the hydrogen molecule is very small, so the female screw 83 and the male screw In the mounting structure described in Patent Document 1 only by screwing with the screw 36, hydrogen may leak from a gap due to the clearance between the female screw 83 and the male screw 36, and the protective tube 58 of the temperature sensor 10 The housing 12 is provided as a separate body, and from the joint 56 between the protective tube 58 and the glass cylinder 48, the joint 54 between the glass cylinder 48 and the housing 12, and the like. Containing there is a risk of leakage.

  Therefore, conventionally, as shown in FIGS. 4 and 5 attached to this specification, in order to ensure airtightness, the protective tube portion 31, the male screw portion 32, the housing seal portion 33, and the lock portion 34 are cut out by cutting. The temperature sensor 4 in which the temperature sensor element 40 and the lead wires 41 and 42 are electrically coupled is accommodated in the insertion port 35 provided in the sensor housing 3 formed integrally with the boss end 2 and provided outside. A female screw portion 22 and a boss end seal portion 23 are provided in the opening to be opened, and the sensor housing 3 is fastened to the boss end 2 by screwing the female screw portion 22 and the male screw portion 32 into the housing seal portion 33. And the boss end seal portion 23 are in close contact with each other and are attached by an airtight structure that maintains airtightness.

  When trying to improve the responsiveness of temperature measurement, it is desirable that the protective tube portion 31 is as thin as possible. However, when the protective tube portion 31 is cut and formed to ensure airtightness, In addition to being difficult to process, the length of the protective tube portion 31 is naturally limited because it must be able to withstand high pressure.

  For this reason, if the sensor housing 3 is to be attached to the boss end 2 from the outside, it is difficult to form the protective tube portion 31 having a length that reaches the inside of the high-pressure hydrogen container 1. It cannot project inside the high-pressure hydrogen container 1.

Therefore, a port 200 is provided in the opening of the boss end 2 from the inside of the high-pressure hydrogen container 1, and a protective tube portion 31 of the sensor housing 3 is disposed in the port 200 so that the high-pressure hydrogen container 1 is introduced into the port 200 and brought into contact with the protective tube portion 31 to enable temperature measurement by the temperature sensor 4.
US Pat. No. 5,743,646 Motohiro Mizuno and three others, “High-pressure hydrogen tank for FCHV”, Japan Society of Automotive Engineers Spring Academic Lecture Preprint, Japan Society of Automotive Engineers, May 20, 2005, NO. 84-05, p. 13-16 Yasuki Yoshida and five others, “Building a high-pressure hydrogen rapid filling system for fuel cell vehicles”, Japan Society of Automotive Engineers Spring Conference Lecture Preprint, Japan Society for Automotive Technology, May 22, 2003, NO. 29-03, p13-16 Atsushi Aoyagi and three others, “Development of fuel consumption measurement method for fuel cell vehicles”, Japan Society for Automotive Engineers Autumn Preliminary Lecture Collection, Japan Society for Automotive Engineers, September 18, 2003, NO. 80-03, p. 5-8

  However, in the conventional pressure sensor mounting structure for a high-pressure vessel, the boss end 2 depends on conditions such as the outside air temperature until the high-pressure hydrogen gas 5 is introduced into the port 200 and the temperature is detected by the temperature sensor 4. Therefore, the measured temperature may be different from the actual temperature of the hydrogen gas in the high-pressure vessel.

  Further, when the replacement of the hydrogen gas introduced into the port 200 is not performed quickly, the error between the temperature of the hydrogen gas in the high-pressure vessel and the measured temperature can be further increased.

In view of the above circumstances, an object of the present invention is to provide a mounting structure for a temperature sensor for a high-pressure hydrogen container that is capable of accurately measuring the temperature in the high-pressure hydrogen container and has excellent responsiveness.

In the invention of claim 1, a temperature sensor for measuring the temperature in the high-pressure hydrogen container in which high-pressure hydrogen is sealed is provided at the boss end that closes the opening provided in the boss that seals the end of the high-pressure hydrogen container. A temperature sensor mounting structure for a high-pressure hydrogen container attached via a sensor housing that holds the temperature sensor inside and protects the temperature sensor,
The temperature sensor includes a sensor element that measures the temperature of the high-pressure hydrogen, and a lead wire that draws the measurement result of the sensor element to the outside, and an insertion hole that opens from the inside of the high-pressure hydrogen container provided at the boss end to the outside In order to place the sensor element in a position protruding from the inside of the high-pressure hydrogen container, withdrawing the lead wire from
The sensor housing is provided separately from the boss end, and has an open end whose one end communicates with the insertion hole and a closed end whose other end is closed, and holds the sensor element inside the closed end. Screwed into a protective tube portion, a seal portion that is in close contact with the seal portion provided at the boss end on the opening end side of the protective tube portion and maintains airtightness with the insertion hole, and a screw portion provided at the boss end. The sensor housing is assembled from the direction of the inside of the high-pressure hydrogen container of the boss end by integrally forming a screw portion for tightly attaching the seal portion by machining a stainless steel material having high hydrogen brittleness resistance. The sensor element is inserted into the protective tube from the direction of the boss end on the outside of the high-pressure hydrogen container .

The protective pipe portion for holding the sensor element therein is disposed inside the position than the inner wall of the high-pressure hydrogen container, since contact with the inside the high-pressure hydrogen container via only the wall of the protective tube portion, more Accurate and responsive temperature measurement is possible.
Since the sensor housing is provided separately from the boss end, the degree of freedom of processing is increased, the overall size of the sensor housing can be reduced, and more precise processing is possible. The gap between the protective tube portion of the sensor housing and the sensor element can be narrowed, and the responsiveness of the sensor element is improved.
Further, since the temperature sensor can be assembled in the protective tube with the boss end removed from the high-pressure vessel, the mounting workability is improved.
Further, the sensor housing can be easily assembled to the boss end by screw tightening, and the seal surface of the sensor housing and the seal surface of the boss end are elastically deformed and sealed by the axial force generated by the tightening. The surfaces bite into each other and come into close contact with each other, so that the airtightness can be firmly maintained.
In addition, since the sensor housing is attached to the inside of the high-pressure hydrogen container, the hydrogen gas pressure in the high-pressure hydrogen container is applied to the sensor housing and acts to increase the adhesion of the seal surface.

According to a second aspect of the present invention, the seal position of the both seal portions is set to a position outside the boss end with respect to the screw portion in a state where the sensor housing and the boss end are screwed together.

  Compared with the case where the position of the seal portion is behind the screw tightening position, the area of the contact surface of the seal portion is smaller, so the surface pressure per unit area applied to the seal portion by the axial force due to screw tightening The airtightness is further improved.

In the invention described in claim 3, the sealing surfaces of the both sealing portions are formed on a plane orthogonal to the screw tightening direction.

  Even if the angle of the taper surface is strictly processed in the metal seal structure with the general contact between the taper surfaces, if the seal is loosened once it is sealed, the deformed seal surface is completely restored to the original shape. In addition, since the sealing position does not completely match the original position depending on the screw tightening strength, there is a possibility that leakage will occur when resealed. In the case of the metal seal structure between the two, since there is little influence due to the difference in the screw fastening angle, it is advantageous in preventing leakage.

In the invention of claim 4, characterized in that said high-pressure hydrogen container is a high-pressure hydrogen container for fuel cell vehicles.

  According to the present invention, the measurement accuracy and responsiveness of the internal temperature of the high-pressure hydrogen container for a fuel cell vehicle can be improved, and the accuracy of filling control during hydrogen filling and fuel consumption measurement during traveling can be improved.

  Embodiments of the present invention will be described below with reference to the drawings. 1 is a cross-sectional view of a main part of a temperature sensor mounting structure for a high-pressure hydrogen container according to the present invention, FIG. 2 is an enlarged cross-sectional view showing details of a portion A surrounded by a circle in FIG. 1, and FIG. It is a partial sectional view of a high pressure hydrogen container to which the invention is applied.

  The high-pressure hydrogen container 1 is a high-pressure container in which hydrogen gas 5 is sealed as a high-pressure fluid. The high-pressure hydrogen container 1 has thick stainless steel bosses 10 at both ends, and a container body is formed by a resin liner 11 formed integrally with the boss 10 by injection molding. The carbon fiber reinforced plastic (CFRP) 12 is continuously wound around the outer surface of the resin liner 11 in a number of layers, thereby forming an extremely high strength while maintaining airtightness.

  Further, the outer surface of the CFRP 12 layer is further reinforced by glass fiber reinforced plastic (GFRP) 13, and both sides are protected from external impacts by shock absorbing pads 14.

  At the center of the boss 10 at both ends of the high-pressure hydrogen container 1, an opening that opens to the outside is provided, and the opening has an approximately cylindrical boss end 2 made of stainless steel having a hexagonal head. It is mounted with an airtight structure by a well-known sealing method.

  The boss 10 and the boss end 2 are made of stainless steel (SUS316L) in consideration of hydrogen embrittlement resistance.

  If a temperature sensor is to be attached to the resin portion (liner 11, CFRP12, GFRP13) of the high-pressure hydrogen container 1, not only is it difficult to ensure hermeticity because it is attached to a curved surface, but also the pressure resistance of the high-pressure hydrogen container 1 is Sex can be lost.

  Therefore, the boss end 2 of the high-pressure hydrogen container 1 is not only for closing the openings of the bosses 10 at both ends of the high-pressure hydrogen container 1, but it is easy to secure a part mounting space due to its thickness. Without hindering the airtightness and pressure resistance of the high pressure hydrogen container 1 for assembling the open / close valve 6 and piping for filling or discharging hydrogen gas, or other components such as the temperature sensor 4 and pressure sensor, etc. It serves as a mounting base.

  As shown in FIG. 3, one of the boss ends 2 attached to the bosses 10 at both ends of the high-pressure hydrogen container 1 has a high-pressure hydrogen container 1 in the high-pressure hydrogen container 1 due to the above-described detailed airtight structure. An opening / closing valve 6 for filling the gas 5 and taking out the high-pressure hydrogen gas 5 from the high-pressure hydrogen container 1, a piping member, a safety valve (not shown), and the like are attached.

  As shown in FIGS. 1 and 2, the other boss end 2 is provided with an insertion hole 20 that opens to the outside along its axis with an inner diameter through which a temperature sensor 4 to be described later can be inserted.

  On the high-pressure hydrogen container 1 side of the insertion hole 20, a female screw portion 22 for assembling a sensor housing 3 described later is formed with a diameter larger than that of the insertion hole 20.

  The boss end 2 is formed with a boss end seal portion 23 for securing airtightness at the tip of the female screw portion 22 in the screw tightening direction. The boss end seal portion 23 forms a plane perpendicular to the screw tightening direction, and the surface is finished with high accuracy in order to improve the adhesion of the metal seal structure described later.

  The sensor housing 3 is made of stainless steel (SUS316L) made of the same material as the boss end 2, and has a cylindrical protective tube portion 31, a male screw portion 32 that engages with the female screw portion 22 provided on the boss end 2, and a housing seal portion 33. And the nut portion 34 are integrally formed by cutting.

  Further, when the sensor housing 3 is assembled to the boss end, one end communicates with the insertion hole 20 provided in the boss end 2 inside the sensor housing 3, and the other end is blocked by the tip of the protective tube portion 31. An insertion hole 20a is provided along the axis.

  The sensor housing 3 is attached to the boss end 2 separately from the boss end 2. That is, both have a structure that can be disassembled, and relatively precise processing is possible when processing both. In particular, when forming a thin hole such as the insertion hole 20 of the boss end 2 or the insertion hole 20a of the protective tube portion 31, if the boss end 2 and the sensor housing 3 are separate, the hole processing is extremely easy.

  The protective tube portion 31 of the sensor housing 3 is formed with a thickness that takes temperature response and pressure resistance into consideration, and the nut portion 34 has a hexagonal outer shape so that it can be tightened with a tool such as a spanner. The male screw portion 32 is formed to be thick and has a screw diameter that is thicker than the outer diameter of the protective tube portion 31 and is strong enough to withstand the tightening of the nut portion 34.

  The thread size, pitch, number of threads, valley diameter, etc. of each of the male screw portion 32 and the female screw portion 22 are determined in consideration of an appropriate surface pressure of the seal surface.

  Further, since the boss 10, the boss end 2 and the sensor housing 3 are formed of the same material, it is possible to suppress the occurrence of loosening of the screw due to the difference in thermal expansion coefficient.

  It should be noted that the sealing positions of both the seal portions 23 and 33 are set to be higher than those of the both screw portions 22 and 32 in a state where the female screw portion 22 of the boss end 2 and the male screw portion 32 of the sensor housing 3 are screwed together. It is in the front, that is, the position in the outer direction of the boss end 2.

  When the positions of the seal portions 23 and 33 are provided behind the screw tightening positions 22 and 32, that is, in the inner direction of the boss end 2, the seal portions 23 and 33 are provided with the female screw provided on the boss end 2. Inevitably larger than the portion 22, the seal area of both seal portions is increased, and the surface pressure is reduced.

  On the other hand, the seal portions 23 and 33 are inevitably smaller than the inner diameters of the screw portions 22 and 32 by providing the seal portions 23 and 33 ahead of the screw tightening positions 22 and 32. Therefore, the contact area is also reduced, and the surface pressure per unit area applied by the axial force generated by tightening the screw portions 22 and 23 is increased, thereby improving the airtightness.

  The housing seal portion 33 forms a vertical plane with respect to the screw tightening direction, and the seal surface is finished with high accuracy in order to improve adhesion.

  The housing seal portion 33 further reduces the area of the contact surface to increase the surface pressure per unit area on the seal surface, and does not cause galling when contacting the boss end housing seal portion 23. Therefore, a conical tapered surface 331 is provided on the outer diameter side of the housing seal portion 33, a conical tapered surface 332 is provided on the inner diameter side, and the sealing surface is a ring-shaped flat surface.

  When the male screw portion 32 of the sensor housing 3 is screwed into the female screw portion 22 provided in the boss end 2 and the lock portion 34 is tightened with a tool such as a spanner, the housing seal portion 33, the boss end seal portion 23, When the male surfaces 32 are in contact with each other and the male threaded portion 32 is further screwed in, both sealing surfaces are elastically deformed by the axial force of the screwing so that the contact surfaces are completely in close contact with each other.

  Even if the screwing of the male screw portion 32 is stopped, the metal seal structure in which the two sealing surfaces are in close contact with each other by the frictional force between the female screw portion 22 and the male screw portion 32 is maintained. Since the inside and outside of the high-pressure hydrogen container 1 are completely separated, the airtightness can be maintained firmly.

  When the female screw portion 22 and the male screw portion 32 are screwed together, if both of the sealing surfaces exceed the yield value when they are screwed in with an excessive force, the two sealing surfaces are By using the elastic range angle method that derives the appropriate surface pressure from the tightening rotation angle up to the range that does not exceed the yield value, or the torque method that limits the screw tightening torque within the range where both the seal surfaces are elastically deformed. Manage the tightening condition.

  The temperature sensor 4 configured by electrically connecting the temperature sensor element 40 and the lead wires 41 and 42 is inserted from the insertion hole 20 of the boss end 2, and the temperature sensor element 40 is a protective tube of the sensor housing 3. The lead wires 41 and 42 led out from the temperature sensor element 40 pass through the insertion hole 20a and the insertion hole 20 and are externally controlled. It is electrically connected to the device 43.

  Although the thermistor is used as the temperature sensor element 40, it is not limited to the thermistor, and a platinum resistance thermometer or the like may be used.

  The inner wall of the sensor housing 3 and the temperature sensor 4 are electrically insulated by an insulating means such as an insulating coating (not shown) applied to the temperature sensor 4.

  Since the housing 3 is attached so that the closed end of the protective tube portion 31 of the sensor housing 3 is located inside the high-pressure hydrogen container 1, the temperature sensor element 40 held in the closed end is also the above-mentioned. Since the temperature inside the high-pressure hydrogen container 1 can be measured directly only through the thin wall surface of the protective tube 31, the temperature measurement error is reduced and the high-pressure hydrogen is reduced. It is possible to respond quickly to a temperature change inside the container 1.

  In addition, since the sensor housing 3 is attached to the inside of the high-pressure hydrogen container 1, the hydrogen gas pressure in the high-pressure hydrogen container 1 is applied to the sensor housing 3 and acts in the direction of increasing the adhesion of the seal surface. .

  However, at the same time, the hydrogen gas pressure in the high-pressure hydrogen container 1 is also applied in the direction of eliminating the axial force of the screw tightening of the screw portions 22 and 32. However, since the rotational force in the loosening direction of the screw tightening is not given from the hydrogen gas pressure, the rotation of the sensor housing 3 due to external force such as vibration can be prevented by means of loose rotation prevention means such as the anaerobic screw fixing agent 341. In this case, the threaded engagement between the female screw portion 22 and the male screw portion 32 does not occur.

  Further, the loosening rotation preventing means may be a locking means provided with a mechanical engaging portion in addition to the anaerobic screw fixing agent 341.

  In order to further improve the temperature responsiveness, a material having high thermal conductivity that improves the thermal conductivity between the protective tube 31 and the temperature sensor element 40 is used as a filler to form the insertion hole 20a and the temperature sensor element 40. The gap may be filled.

  In the present embodiment, the temperature sensor 4 is provided on one of the boss ends 2 alone. However, according to the present invention, the temperature sensor 4 can be made relatively small. It can also be attached together with other members such as the valve 6, and by concentrating the piping and wiring on the boss end 2 on one side, it is possible to reduce the labor required for handling.

The principal part sectional drawing which shows the attachment structure of the temperature sensor for high pressure containers in embodiment of this invention. The expanded sectional view of the A section in FIG. The partial sectional view of the high-pressure hydrogen container to which the present invention was applied. The principal part sectional drawing which shows the attachment structure of the conventional temperature sensor for high pressure hydrogen containers. The expanded sectional view of the A section in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 High pressure hydrogen container 2 Boss end 20, 20a Insertion hole 22 Female screw part 23 Boss end seal part 3 Sensor housing 31 Protection pipe part 32 Male screw part 33 Housing seal part 331, 332 Tapered surface 34 Nut part 341 Anaerobic screw fixing agent 4 Temperature sensor 40 Temperature sensor element 41, 42 Lead wire 43 Control device 5

Claims (4)

A temperature sensor that measures the temperature in the high-pressure hydrogen container in which high-pressure hydrogen is sealed is held inside the boss end that closes the opening provided in the boss that seals the end of the high-pressure hydrogen container. A temperature sensor mounting structure for a high-pressure hydrogen container mounted via a sensor housing that protects the temperature sensor,
The temperature sensor consists of a sensor element that measures the temperature of the high-pressure hydrogen, and a lead wire that draws the measurement result of the sensor element to the outside,
In order to draw out the lead wire from the insertion hole that opens to the outside from the inside of the high-pressure hydrogen container provided at the boss end, and to place the sensor element at a position protruding inside the high-pressure hydrogen container,
The sensor housing is provided separately from the boss end,
One end has an open end that communicates with the insertion hole and a closed end that the other end closes,
A protective tube part for holding the sensor element inside the closed end;
A seal portion that is in close contact with the seal portion provided on the boss end on the opening end side of the protective tube portion and maintains airtightness with the insertion hole;
A screw part that is screwed with a screw part provided on the boss end to bring the seal part into close contact;
Is integrally formed by machining stainless steel with high hydrogen embrittlement resistance,
The high-pressure hydrogen, wherein the sensor housing is assembled from the direction of the boss end inside the high-pressure hydrogen container, and the sensor element is inserted into the protective tube portion from the direction of the boss end outside the high-pressure hydrogen container. Temperature sensor mounting structure for containers. 2. The temperature sensor mounting structure for a high-pressure hydrogen container according to claim 1, wherein the seal position of both the seal portions is set at a position outside the boss end with respect to the screw portion in a state where the sensor housing and the boss end are screwed together . The temperature sensor mounting structure for a high-pressure hydrogen container according to claim 1 or 2, wherein the sealing surfaces of both the sealing portions are formed on a plane orthogonal to the screw tightening direction . The temperature sensor mounting structure for a high-pressure hydrogen container according to any one of claims 1 to 3, wherein the high-pressure hydrogen container is a high-pressure hydrogen container for a fuel cell vehicle .