Semiconductor package

Abstract

To provide a semiconductor package that can suppress deterioration.SOLUTION: A pressure introduction part 12 is a pipe for delivering exhaust gas inflowing from an exhaust pipe 40 to a pressure detection chamber 2 as a pressure medium, and has a switch 13 that receives physical external force and is actuated to open / close. A slide part 32 receives pressure due to a branch of the exhaust gas and is pushed in a first direction, then the switch 13 is put in an opened state, and the exhaust pipe 40 and the pressure detection chamber 2 are spatially connected. An electromagnet 38 of a second holding part 39 pulls the slide part 32 toward the first direction, and keeps the opened state of the switch 13. A first holding part 36 is a compression coil spring, and contracts by receiving a compression load from the pressure medium 52. The switch 13 always receives external force 61 trying to get back to a natural length from the first holding part 36, and upon dissipation of the pressure medium 52, the slide part 32 is pushed back toward a second direction opposite to the first direction by the external force 61 into a closed state, and shields the pressure detection chamber 2 from the exhaust gas.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This disclosure relates to semiconductor packages. [Background technology]

[0002] Patent Document 1 describes a technology that has a pressure switching valve that is operated and controlled to open and close an intake pressure passage between an intake system of an internal combustion engine and a pressure sensor, and that uses the intake pressure (negative pressure) generated by introducing air into the intake pressure passage that is closed by the pressure switching valve during deceleration of the internal combustion engine to clean fuel, moisture, etc. from the intake pressure passage. Patent Document 2 describes a technology that has an opening / closing valve that moves in accordance with the negative pressure in the intake system to open and close a communication passage between a pressure detection chamber and the outside (atmosphere), and that becomes close to a valve open state when the accelerator is ON, preventing dirt from entering the pressure detection chamber due to the flow of fresh air introduced into the pressure detection chamber from the outside. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Utility Model Registration No. 2520601 [Patent Document 2] Japanese Patent Application Laid-Open No. 2001-124652 Summary of the Invention [Problem to be solved by the invention]

[0004] When measuring intake pressure as in Patent Documents 1 and 2, the pressure medium is nearly equal to the outside air (atmosphere), so there is no need to consider deterioration of the semiconductor package used for pressure measurement (pressure sensor circuit and its components) due to the pressure medium even if it is exposed to the pressure medium for a long period of time. However, when measuring exhaust pressure, the engine piping is sealed at all times, so the inside of the semiconductor package is exposed to a pressure medium containing corrosive substances for a long period of time. For this reason, there is a strong concern about deterioration of the semiconductor package used for pressure measurement.

[0005] An object of this disclosure is to provide a semiconductor package that can suppress deterioration. [Means for solving the problem]

[0006] A semiconductor package according to one aspect of the present disclosure is a semiconductor package that detects the pressure of gas flowing through an engine piping, and includes a pressure sensor chip, a pressure detection chamber, and a pressure introduction section, as follows: The pressure sensor chip converts pressure received from a first pressure medium into an electrical signal. The pressure detection chamber houses the pressure sensor chip. The first pressure medium is transmitted to the pressure detection chamber. The pressure introduction section is disposed between the engine piping and the pressure detection chamber. The gas that becomes the first pressure medium flows into the pressure introduction section from the engine piping. The pressure introduction section has a switch that moves and opens and closes in response to a physical external force. In an open state, the switch spatially connects the engine piping and the pressure detection chamber via the pressure introduction section, and in a closed state, spatially isolates the engine piping and the pressure detection chamber. [Effects of the Invention]

[0007] The semiconductor package according to the present disclosure has the effect of suppressing deterioration. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view schematically illustrating a structure of a semiconductor package according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view schematically illustrating an example of the structure of the pressure sensor of FIG. [Figure 3] 2 is an enlarged cross-sectional view showing the structure of the switch of FIG. 1. FIG. [Figure 4] FIG. 4 is a perspective view schematically showing the structure of the sliding portion (upper curved surface side) of FIG. 3. [Figure 5] FIG. 4 is a perspective view schematically showing the structure of the sliding portion (curved surface lower side) of FIG. 3. [Figure 6]2 is a cross-sectional view (part 1) schematically illustrating a state during transition from an OFF state to a completely ON state of the switch in FIG. 1. FIG. [Figure 7] 2 is a cross-sectional view (part 2) schematically illustrating a state during transition from an OFF state to a completely ON state of the switch in FIG. 1. FIG. [Figure 8] 1. FIG. 4 is a cross-sectional view (part 3) schematically illustrating a state during transition from an OFF state to a completely ON state of the switch of FIG. [Figure 9] FIG. 2 is a cross-sectional view schematically showing the switch of FIG. 1 in a completely on state. [Figure 10] FIG. 1 is a cross-sectional view schematically illustrating the structure of a semiconductor package according to a reference example. DETAILED DESCRIPTION OF THE INVENTION

[0009] <Summary of Embodiments of the Present Disclosure> (1) A semiconductor package according to one aspect of the present disclosure is a semiconductor package that detects the pressure of gas flowing through an engine pipe, and includes a pressure sensor chip, a pressure detection chamber, and a pressure introduction section, as follows: The pressure sensor chip converts pressure received from a first pressure medium into an electrical signal. The pressure detection chamber houses the pressure sensor chip. The first pressure medium is transmitted to the pressure detection chamber. The pressure introduction section is disposed between the engine pipe and the pressure detection chamber. The gas that becomes the first pressure medium flows from the engine pipe into the pressure introduction section. The pressure introduction section has a switch that moves and opens and closes in response to a physical external force. In an open state, the switch spatially connects the engine pipe and the pressure detection chamber via the pressure introduction section, and in a closed state, spatially separates the engine pipe and the pressure detection chamber.

[0010] According to the above disclosure, when the switch is closed, the pressure detection chamber can be shielded from the high-temperature, high-humidity gas in the engine pipe, thereby suppressing deterioration of the pressure sensor chip and its components due to rust, corrosion, moisture absorption expansion, etc.

[0011] (2) Furthermore, in the semiconductor package according to this disclosure, in the above-mentioned (1), the switch may be moved in a first direction and be in an open state when subjected to pressure from a second pressure medium that is a tributary of the first pressure medium.

[0012] According to the above disclosure, the open state of the switch can be easily achieved physically.

[0013] (3) Furthermore, in the semiconductor package according to this disclosure, in the above-mentioned (1) or (2), the switch may have a first retaining portion that prevents the switch from moving in the first direction, and when the second pressure medium disappears, the first retaining portion may push the switch back in a second direction opposite to the first direction, thereby closing the switch.

[0014] According to the disclosure above, the switch can be maintained in a closed state when the engine is stopped.

[0015] (4) In the semiconductor package according to the present disclosure, in the above-described (3), the first holding portion is a compression coil spring that generates a pressing load that presses the switch back in the second direction. The switch may constantly receive the pressing load from the first holding portion.

[0016] According to the disclosure above, the switch can be transitioned from the open state to the closed state simultaneously with stopping the engine.

[0017] (5) In the semiconductor package according to the present disclosure, in the above-mentioned (4), the switch may be maintained in a closed state by the pressing load applied by the first holding portion.

[0018] According to the above disclosure, maintaining the switch in a closed state can be achieved physically easily.

[0019] (6) In the semiconductor package according to the present disclosure, in the above-mentioned (2), the switch has a second holding portion that pulls the switch in the first direction and holds it. When the switch moves in the first direction to an open state, or when the switch moves in the first direction to approach the open state, the switch may be held by the second holding portion and maintain the open state.

[0020] According to the disclosure above, when the switch is in the open state, the switch can be prevented from being pushed back in the second direction by the first holding portion.

[0021] (7) In the semiconductor package according to the present disclosure described above in (6), the second holding portion may have an electromagnet that generates an attractive force that attracts the switch in the first direction.

[0022] According to the above disclosure, maintaining the switch in an open state can be achieved physically easily.

[0023] (8) Furthermore, in the semiconductor package according to this disclosure, in the above-mentioned (7), the second holding portion may attract and hold the switch by the attractive force when the switch, which has moved in the first direction, approaches the electromagnet within a predetermined distance.

[0024] According to the above disclosure, it is possible to prevent the switch from being in a normally open state.

[0025] (9) Furthermore, in the semiconductor package according to the present disclosure, in the above-mentioned (7), power may be supplied to the coil of the electromagnet and to the pressure sensor chip from the same power source.

[0026] According to the above disclosure, it is possible to easily supply power to the coil of the electromagnet.

[0027] (10) Furthermore, in the semiconductor package according to this disclosure, in any one of (1) to (9) above, the switch may have an air-opening port, and in a closed state, the pressure detection chamber may be spatially connected to the outside via the air-opening port.

[0028] According to the disclosure above, when the switch is in the closed state, the pressure detection chamber can be opened to the atmosphere and exposed to the atmosphere (outside air), which can significantly reduce deterioration of the pressure sensor chip and its constituent members.

[0029] <Findings underlying this disclosure> First, the structure of an on-board sensor package for measuring exhaust pressure of an internal combustion engine (engine) will be described as a semiconductor package of a reference example. Fig. 10 is a cross-sectional view that schematically shows the structure of the semiconductor package of the reference example. The semiconductor package 110 of the reference example shown in Fig. 10 is an on-board sensor package that includes a pressure sensor 111 and a pressure introducing portion 112, and is attached to the piping (exhaust pipe 120) of the engine exhaust system. The pressure sensor 111 has a pressure sensor chip (not shown) mounted in the internal space of a case 101 (hereinafter referred to as a pressure detection chamber).

[0030] The case 101 is a resin molded product in which a lead frame (not shown) is insert-molded. A pressure sensor chip is electrically connected to the lead frame insert-molded into the case 101 by bonding wires (not shown). The pressure sensor chip is an epitaxially resistive type that utilizes the epitaxially resistive effect of diffused resistors formed inside a silicon (Si) semiconductor, and is a surface-pressure-receiving semiconductor IC (Integrated Circuit) in which the gauge surface (circuit surface on which a strain gauge is provided) is the pressure-receiving surface for the pressure medium 131.

[0031] Pressure introducing section 112 is a passage for pressure medium 131 that is transmitted to the pressure detection chamber. Pressure introducing section 112 is a resin pipe (resin piping) that is integrally molded with case 101, and one open end is connected to the pressure detection chamber. The other open end of pressure introducing section 112 is inserted into a hole (hereinafter referred to as a mounting hole) 120a formed in exhaust pipe 120 of the engine, thereby directly attaching semiconductor package 110 to exhaust pipe 120. The pressure detection chamber (space) and the inside (space) of exhaust pipe 120 are connected via pressure introducing section 112, forming a constantly continuous space.

[0032] An O-ring (not shown) attached to the outer periphery of pressure introducing portion 112 seals the gap at the joint between pressure introducing portion 112 and exhaust pipe 120, maintaining airtightness. Pressure introducing portion 112 is short, and pressure sensor 111 is disposed in a position relatively close to exhaust pipe 120. Exhaust pipe 120 is a hollow cylindrical resin pipe through which exhaust gas 130 flows during the exhaust stroke of the engine, and connects the engine cylinder (not shown) to the outside (atmosphere). A portion of exhaust gas 130 passes through pressure introducing portion 112 and is transmitted to the pressure detection chamber as pressure medium 131.

[0033] The operation of the semiconductor package 110 of the reference example will now be described. When the engine is running, combustion gases generated in the cylinders of the engine during the combustion and expansion stroke of the internal combustion engine are discharged as exhaust gases 130 to the outside of the vehicle through the exhaust pipe 120 during the exhaust stroke. At this time, the exhaust gases 130 flow from the exhaust pipe 120 into the pressure introducing portion 112 and are transmitted to the pressure detection chamber of the pressure sensor 111 as a pressure medium 131. The pressure sensor 111 outputs, as an electrical signal, the distortion of the diaphragm of the pressure sensor chip caused by the pressure received from the pressure medium 131.

[0034] Because the O-ring increases the airtightness between the pressure introduction part 112 and the exhaust pipe 120, the pressure medium 131 that flows from the exhaust pipe 120 into the pressure introduction part 112 is transmitted to the pressure sensor chip without leaking to the outside. Normally, the exhaust pipe 120 does not have an atmosphere release valve for introducing the atmosphere, so it is always sealed and not open to the atmosphere. When the engine is stopped, the intake of air (oxygen) into the engine stops, so exhaust gas 130 remains in the exhaust pipe 120, and the inside of the exhaust pipe 120 is exposed to high-temperature, high-humidity exhaust gas 130.

[0035] Because the airtightness between the pressure introducing section 112 and the exhaust pipe 120 is increased, exhaust gas 130 in the exhaust pipe 120 and in the semiconductor package 110 (in the pressure introducing section 112 and the pressure detection chamber) is less likely to be discharged to the outside. The path of the pressure medium 131 (exhaust gas 130) from the exhaust pipe 120 to the pressure detection chamber is always spatially continuous, and no member is provided to shield the pressure sensor chip from the exhaust gas 130. The pressure sensor chip continues to be exposed to the exhaust gas 130 remaining in the exhaust pipe 120 without being exposed to the outside air even after the engine is stopped.

[0036] Exhaust gas 130 contains corrosive environmentally hazardous substances such as sulfur oxides (SOx) and nitrogen oxides (NOx), as well as water vapor generated when fuel (such as gasoline) is burned. Therefore, if the inside of semiconductor package 110 is exposed to pressure medium 131 (especially moisture), there is a growing concern that the pressure sensor chip and its components may deteriorate due to rust, corrosion, hygroscopic expansion, etc. As described above, the airtightness between pressure introducing portion 112 and exhaust pipe 120 is increased, so the inside of semiconductor package 110 is exposed to high-temperature, high-humidity pressure medium 131 for a long period of time.

[0037] One of the problems to be solved in this embodiment is to suppress deterioration of the pressure sensor chip and its constituent members (bonding wires, etc.).

[0038] Preferred embodiments of the semiconductor package according to this disclosure will be described in detail below with reference to the accompanying drawings. In the following description of the embodiments and the accompanying drawings, like components are designated by like reference numerals, and duplicated descriptions will be omitted.

[0039] (Details of the embodiment) A semiconductor package according to an embodiment that solves the above-mentioned problems will be described below. FIG. 1 is a cross-sectional view schematically showing the structure of a semiconductor package according to an embodiment. FIG. 1 shows a switch 13 in a completely off state. FIG. 2 is a cross-sectional view schematically showing an example of the structure of the pressure sensor of FIG. 1. FIG. 3 is a cross-sectional view showing an enlarged view of the structure of the switch of FIG. 1. FIGS. 4 and 5 are perspective views schematically showing the structure of the sliding portion of FIG. 3. FIGS. 4 and 5 show the sliding portion 32 as viewed from the upper curved surface side and the lower curved surface side, respectively. FIGS. 6 to 8 are cross-sectional views schematically showing the switch of FIG. 1 in the middle of transitioning from an off state to a completely on state. FIG. 9 is a cross-sectional view schematically showing the switch of FIG. 1 in a completely on state.

[0040] 1 to 5 and 9, a semiconductor package 10 according to an embodiment includes a pressure sensor 11 and a pressure introducing portion 12, and is an in-vehicle sensor package for pressure measurement that is attached to the piping of an internal combustion engine (engine). Here, an example is described in which the semiconductor package 10 is attached to the piping (exhaust pipe 40) of the engine's exhaust system to measure exhaust pressure, but the semiconductor package 10 may also be attached to other piping within a vehicle. The semiconductor package 10 is useful when it is desired to expose the pressure sensor 11 to the outside air (atmosphere) during standby (when pressure is not being measured) in a pressure measurement application in which gas flowing in a piping without an atmospheric release valve is used as the pressure medium, and is particularly suitable for pressure measurement (exhaust pressure measurement) of exhaust gas 50 whose pressure medium contains a corrosive substance.

[0041] The semiconductor package 10 is a component that constitutes the exhaust system of the engine, and is attached to an exhaust pipe 40. The pressure sensor 11 has a pressure sensor chip (semiconductor substrate) 3 mounted in a space (pressure detection chamber) 2 inside the case 1 (see FIG. 2), and outputs the pressure received by the pressure sensor chip 3 as an electrical signal to an external circuit via a lead frame 4. The pressure sensor 11 receives a voltage supply from a power supply IC (not shown) of an ECU (Engine Control Unit) for engine control, or from a power supply IC (not shown) of an ECU (Electronic Control Unit) for controlling the driving performance, safety, and environmental friendliness of the vehicle, and is controlled by the ECU.

[0042] The case 1 is a resin molded product in which the lead frame 4 is insert-molded. The case 1, the storage container main body 9 (described later), the pressure introducing section 12 (first to third pipes 21 to 23 (described later)), the support housing 31 (described later), the slide section 32 (described later), and the exhaust pipe 40 are made of a high-performance resin, such as PPS (Poly Phenylene Sulfide), that has excellent heat resistance, mechanical strength, durability (chemical resistance, abrasion resistance), non-flammability, electrical insulation, and processability, known as a super engineering plastic. Therefore, compared to when these engine exhaust system components are made of metal, it is possible to suppress corrosion caused by exhaust gas 50 and reduce the weight of the engine exhaust system.

[0043] The pressure detection chamber 2 is a substantially rectangular (inverted trapezoidal in FIG. 2 ) space surrounded by the inner wall of the case 1. When a switch 13 (described later) is on (open), the pressure detection chamber 2 is exposed to exhaust gas 50 transmitted as a pressure medium 51 from the exhaust pipe 40 via the pressure introduction portion 12. When the switch 13 is off (closed), the pressure detection chamber 2 is spatially separated from the exhaust pipe 40 and is open to the atmosphere and exposed to the outside air. A recess 2a for mounting the pressure sensor chip 3 is provided on the top surface of the pressure detection chamber 2 (the inner wall of the case 1 on the opposite side from the exhaust pipe 40). A pressure introduction port 2b to the pressure detection chamber 2 is provided on the bottom surface of the pressure detection chamber 2 (the inner wall of the case 1 on the exhaust pipe 40 side). The pressure detection chamber 2 and the first pipe 21 are connected by the pressure introduction port 2b, forming a constantly continuous space.

[0044] The pressure sensor chip 3 is an epitaxially resistive semiconductor IC that utilizes the epitaxial effect of a diffused resistor (gauge resistor) formed inside a silicon (Si) semiconductor, and is a surface-sensitive pressure-receiving type semiconductor IC in which the gauge surface (circuit surface on which a strain gauge is provided) serves as the pressure-receiving surface for the pressure medium 51 to be detected. The pressure sensor chip 3 has a diaphragm structure in which the thickness of the central portion is made thinner than the thickness of the outer periphery by forming a recess 3b by etching the central portion from the back side. The pressure sensor chip 3 includes a diaphragm (pressure-receiving portion) 3a that bends when pressure is applied, a strain gauge (not shown), and a calculation circuit portion (not shown) for amplifying and correcting the output of the strain gauge. The diaphragm 3a has, for example, a circular planar shape.

[0045] The strain gauge is composed of multiple gauge resistors (not shown) made of a piezo-resistive material (Si semiconductor) and bridge-connected, with approximately the same shape and resistance value. The strain gauge is provided on the front side of the pressure sensor chip 3, facing the diaphragm 3a. Each gauge resistor is electrically connected to the lead frame 4 via a surface electrode (not shown) on the front side of the pressure sensor chip 3 and a bonding wire 5. The strain of the diaphragm 3a caused by pressure from the pressure medium 51 is converted by the strain gauge into an electrical signal proportional to the pressure (a potential difference generated across the bridge of the gauge resistors proportional to the pressure), and the signal is output to an external circuit via the lead frame 4. The lead frame 4 is made primarily of, for example, phosphor bronze.

[0046] The pressure sensor chip 3 is bonded at its outer periphery on its back surface to one surface of the base member 6 by, for example, electrostatic bonding (anodic bonding) so that the recess 3b on the back surface is covered by the base member 6. The other surface of the base member 6 is die-bonded (fixed) to the bottom surface 8a of the sensor mounting portion 8 via an adhesive 7. The pressure sensor chip 3 and the base member 6 are arranged away from the side wall of the sensor mounting portion 8. The base member 6 is, for example, a glass substrate made of heat-resistant glass. The sensor mounting portion 8 is a recess that houses the pressure sensor chip 3, and is formed inside the housing body 9. The pressure sensor chip 3 and bonding wires 5 may be sealed inside the sensor mounting portion 8 with a general sealing material. The housing body 9 only needs to be sized to fit inside the recess 2a of the pressure detection chamber 2, and the planar shapes of the housing body 9 and the recess 2a of the pressure detection chamber 2 can be modified in various ways.

[0047] The pressure introduction section 12 includes first to third pipes 21 to 23 and a switch 13. The first to third pipes 21 to 23 are hollow, cylindrical resin pipes having a diameter smaller than that of the exhaust pipe 40. The first pipe 21 is molded integrally with the case 1, and one open end is connected to the pressure introduction port 2b of the pressure detection chamber 2. The first pipe 21 protrudes from the bottom surface of the case 1 (the surface on the switch 13 side) and is disposed between the case 1 and the switch 13. The other open end is inserted into a hole (hereinafter referred to as a mounting hole) 31a formed in the curved upper portion of a support housing 31 of the switch 13 (the side surface on the pressure sensor 11 side). The first pipe 21 may be molded integrally with the support housing 31. When the switch 13 is turned on, the first pipe 21 serves as a passage for the pressure medium 51 transmitted to the pressure detection chamber 2, and when the switch 13 is turned off, the first pipe 21 is open to the atmosphere and serves as a path for outside air to enter the pressure detection chamber 2. The length of the first pipe 21 is short, and the pressure sensor 11 and the switch 13 are located relatively close to each other.

[0048] The second pipe 22 is disposed between the switch 13 and the exhaust pipe 40. One open end of the second pipe 22 is inserted into a mounting hole 31b formed in the lower curved surface (side surface on the exhaust pipe 40 side) of the support housing 31 of the switch 13. The second pipe 22 may be integrally molded with the support housing 31. The semiconductor package 10 is directly attached to the exhaust pipe 40 by inserting the other open end of the second pipe 22 into a mounting hole 40a formed in the curved surface (side surface) of the exhaust pipe 40. Exhaust gas 50 flowing through the exhaust pipe 40 when the engine is running (while the vehicle is running or idling) flows into the second pipe 22 as a pressure medium (first pressure medium) 51. The second pipe 22 is a passage for the pressure medium 51 to be transmitted to the pressure detection chamber 2. The second pipe 22 is always spatially continuous with the exhaust pipe 40. The inside of the second pipe 22 is not directly exposed to the outside air. The second pipe 22 is short in length, and the pressure sensor 11 is disposed at a position relatively close to the exhaust pipe 40 .

[0049] The third pipe 23 is disposed between the switch 13 and the exhaust pipe 40. One open end of the third pipe 23 is inserted into a pressure inlet 31c formed on the bottom surface of the support housing 31 of the switch 13. The third pipe 23 may be molded integrally with the support housing 31. The other open end of the third pipe 23 is inserted into a mounting hole formed on the side surface of the second pipe 22. The third pipe 23 may be molded integrally with the second pipe 22. The third pipe 23 is a passage for a pressure medium (second pressure medium) 52 that powers the slide portion 32. The third pipe 23 is always spatially connected to the exhaust pipe 40 via the second pipe 22, and the inside of the third pipe 23 is not directly exposed to the outside air. The third pipe 23 is a branch path for directing a tributary of the exhaust gas 50 (pressure medium 51) that flows from the exhaust pipe 40 into the second pipe 22 toward the switch 13 as pressure medium 52.

[0050] The switch 13 has the function of being turned on when the engine is running, connecting a passage for the pressure medium 51 (a first through-hole 32a of the slide portion 32, described later) between the first and second pipes 21 and 22, thereby communicating between the pressure detection chamber 2 and the exhaust pipe 40. The switch 13 is continuously maintained in a completely on state by a second holding portion 39, described later, while the engine is running, shielding the pressure detection chamber 2 from the atmosphere and maintaining communication between the pressure detection chamber 2 and the exhaust pipe 40. On the other hand, the switch 13 is turned off when the engine is stopped (parked), spatially disconnecting the first and second pipes 21 and 22, thereby shielding the pressure detection chamber 2 from the pressure medium 51, and connecting a path for the atmosphere (a second through-hole 32b of the slide portion 32, described later) to the pressure detection chamber 2, thereby opening the pressure detection chamber 2 to the atmosphere. The switch 13 is continuously maintained in a completely off state by a first holding portion 36, described later, while the engine is stopped, shielding the pressure detection chamber 2 from the pressure medium 51 and maintaining the pressure detection chamber 2 open to the atmosphere.

[0051] Specifically, the switch 13 has a support housing 31, a sliding portion 32, ceilings 33 to 35, and first and second holding portions 36 and 39 (FIG. 3). The support housing 31 is hollow and cylindrical, and houses the sliding portion 32 inside. The support housing 31 is disposed between the pressure sensor 11 (case 1) and the exhaust pipe 40, with its curved surface (side surface) facing the bottom surface of the case 1 and the curved surface of the exhaust pipe 40. Mounting holes 31a and 31b are formed in the upper and lower curved surfaces of the support housing 31, respectively, penetrating the support housing 31 from the outer wall to the inner wall. The support housing 31 is connected to the first pipe 21 through the mounting hole 31a in the upper curved surface, and is always connected to the pressure detection chamber 2 via the first pipe 21. The support housing 31 is connected to the second pipe 22 through a mounting hole 31b in the lower part of the curved surface, and forms a space that is always continuous with the exhaust pipe 40 via the second pipe 22.

[0052] Each bottom surface of the support housing 31 is formed with a pressure inlet 31c and an air-opening port 31d, which penetrate the support housing 31 from its outer wall to its inner wall. The support housing 31 is connected to the third pipe 23 via the pressure inlet 31c, and is always connected to the exhaust pipe 40 via the third and second pipes 23 and 22. The support housing 31 is always connected to the outside (outside the vehicle) via the air-opening port 31d. The space inside the support housing 31 that is connected to the exhaust pipe 40 is sealed from the outside air by the sliding portion 32 and sealings 33 and 34. The support housing 31 supports the sliding portion 32 in a manner that allows it to move (slide) in the axial direction of the support housing 31 (a direction perpendicular to the bottom surface: the horizontal direction in FIG. 3). The support housing 31 has the function of preventing the sliding portion 32 from shifting in the radial direction of the support housing 31 (a direction perpendicular to the axial direction: the vertical direction in FIG. 3).

[0053] When the switch 13 is turned on, the mounting holes 31a and 31b of the support housing 31 expose the open ends of a first through-hole 32a (described later) of the slide portion 32. The mounting holes 31a and 31b of the support housing 31 may or may not face each other in the radial direction of the support housing 31. The pressure inlet 31c and the open-to-atmosphere port 31d of the support housing 31 may or may not face each other in the axial direction of the support housing 31. The pressure inlet 31c is preferably formed, for example, in the center of the bottom surface of the support housing 31. This can suppress dispersion of pressure from the pressure medium 52 when the slide portion 32 is moved in the axial direction of the support housing 31 within the support housing 31. The open-to-atmosphere port 31d of the support housing 31 only needs to be spatially continuous with the second through-hole 32b (described later) of the slide portion 32, and the arrangement thereof can be set appropriately.

[0054] The sliding portion 32 is a cylindrical resin member having a diameter slightly smaller than the inner diameter of the supporting housing 31 (the diameter of the hollow portion of the supporting housing 31) and a height shorter than that of the supporting housing 31. The sliding portion 32 is housed inside the supporting housing 31 so that its axial direction (the direction perpendicular to the bottom surface) coincides with that of the supporting housing 31. The gap between the curved surface of the sliding portion 32 and the curved inner wall of the supporting housing 31 is partially closed by seals 33 and 34. The sliding portion 32 is supported by the curved inner wall of the supporting housing 31 via the seals 33 and 34. It is sufficient that the sliding portion 32 is supported by the curved inner wall of the supporting housing 31 in a state in which it can move in the axial direction within the supporting housing 31 when it receives a physical external force in the axial direction (a pressing load from the first holding portion 36, which will be described later, and a compressive load 62 on the first holding portion 36 by the pressure medium 52).

[0055] First and second through holes 32a and 32b are formed in the slide portion 32. The first and second through holes 32a and 32b have a substantially circular planar shape. The first through hole 32a penetrates the slide portion 32 from the upper curved surface (the side surface on the first pipe 21 side) to the lower curved surface (the side surface on the second pipe 22 side) (see FIGS. 3 to 5). When the switch 13 is turned on, the first through hole 32a moves between the first and second pipes 21 and 22, connecting the first pipe 21 and the second pipe 22 (see FIG. 9). Therefore, the first through hole 32a serves as a passage for the pressure medium 51 transmitted to the pressure detection chamber 2 when the switch 13 is turned on. The diameter of the first through hole 32a is equal to or smaller than the diameters of the first and second pipes 21 and 22, and is preferably as large as possible. The larger the diameter of the first through hole 32a, the smaller the pressure change in the passage for the pressure medium 51 when the switch 13 is turned on.

[0056] By making the diameter of the first through hole 32a smaller than the diameters of the first and second pipes 21 and 22, the entire open ends of the first through hole 32a are reliably opposed to the open ends of the first and second pipes 21 and 22 on the sliding portion 32 side when the switch 13 is fully on. This increases the airtightness between the first through hole 32a and the first and second pipes 21 and 22 when the switch 13 is fully on, preventing the pressure medium 51 from leaking (pressure leaking) into the gap between the curved surface of the sliding portion 32 and the curved inner wall of the support housing 31. During the movement of the sliding portion 32 of the switch 13 (during the axial sliding), there may be a period in which both the first and second through holes 32a and 32b are in communication with the first pipe 21 (see FIG. 6 ). During the period in which both the first and second through holes 32a and 32b are in communication with the first pipe 21, the first through hole 32a is preferably disconnected from the second pipe 22.

[0057] For example, the first through hole 32a has a cross-sectional shape that is bent in a generally L-shape at one part so that the opening end on the lower side of the curved surface of the slide portion 32 is located closer to the pressure-receiving surface of the pressure medium 52 (the bottom surface facing the pressure inlet 31c of the slide portion 32) than the opening end on the upper side of the curved surface of the slide portion 32. As a result, during a period in which both the first and second through holes 32a, 32b are in communication with the first pipe 21, the first through hole 32a can be in communication only with the first pipe 21, and the first through hole 32a can be separated from the second pipe 22. Furthermore, during a period in which the first and second pipes 21, 22 are in communication with each other via the first through hole 32a, the second through hole 32b can be separated from the first pipe 21 (see FIGS. 8 and 9). When the slide portion 32 of the switch 13 is movable, there may be a period in which only the first through-hole 32a communicates with the first pipe 21 and the first through-hole 32a does not communicate with the second pipe 22 (see FIG. 7).

[0058] The second through-hole 32b penetrates the slide portion 32 closer to the atmosphere-opening port 31d of the support housing 31 than the first through-hole 32a (see FIGS. 3 and 4). The second through-hole 32b has one open end at the curved upper portion of the slide portion 32, and the other open end is always spatially connected to the outside via the atmosphere-opening port 31d of the support housing 31. The second through-hole 32b communicates with the first pipe 21 when the switch 13 is off, and serves as a path for outside air to enter the pressure detection chamber 2 (see FIG. 1). When the switch 13 is off, the first pipe 21 and the pressure detection chamber 2 are open to the atmosphere via the second through-hole 32b. The other open end of the second through-hole 32b may be located, for example, on the bottom surface of the slide portion 32 facing the atmosphere-opening port 31d (the bottom surface opposite the pressure-receiving surface of the pressure medium 52), and preferably faces the atmosphere-opening port 31d in the axial direction of the slide portion 32.

[0059] The cross-sectional shape of the second through-hole 32b can be appropriately determined as long as one open end of the second through-hole 32b is located at the upper curved surface of the slide portion 32 and the other open end is spatially connected to the outside via the atmosphere-opening port 31d. FIG. 3 illustrates a case in which the second through-hole 32b has a substantially L-shaped cross-sectional shape that penetrates the slide portion 32 from the upper curved surface to the bottom surface facing the atmosphere-opening port 31d. The diameter of the second through-hole 32b is preferably equal to or smaller than the diameter of the first pipe 21 and is as small as possible. The smaller the diameter of the second through-hole 32b, the shorter the period until the first pipe 21 and the atmosphere-opening port 31d are spatially disconnected after engine start. This shortens the period during which the pressure detection chamber 2 is open to the atmosphere while the engine is running, thereby improving the pressure detection accuracy of the pressure sensor 11.

[0060] The second through-hole 32b is preferably separated from the first pipe 21 during the period when the pressure medium 51 is being transmitted to the pressure detection chamber 2 (the period when the first and second pipes 21, 22 are in communication with each other via the first through-hole 32a) (see FIGS. 8 and 9). By separating the second through-hole 32b from the first pipe 21, the first pipe 21 is spatially separated from the atmosphere-opening port 31d. This prevents outside air from entering the pressure detection chamber 2 during the period when the pressure medium 51 is being transmitted to the pressure detection chamber 2. The second through-hole 32b is located in a space within the support housing 31 that is continuous with the outside air, and is shielded from a space within the support housing 31 that is continuous with the exhaust pipe 40 by the slide portion 32 and the sealing 34. The distance between the first and second through-holes 32a, 32b can be set appropriately depending on the heights (axial lengths) of the support housing 31 and the slide portion 32.

[0061] The seals 33 and 34 are, for example, general O-rings that contact the curved surface of the sliding portion 32 and surround the outer periphery of the sliding portion 32 (see FIGS. 4 and 5). The seals 33 and 34 support the curved surface of the sliding portion 32 against the curved inner wall of the supporting housing 31. The seals 33 and 34 only need to protrude from the curved surface of the sliding portion 32, and may be fixed by fitting into grooves provided in the curved surface of the sliding portion 32. The seal 33 is disposed closer to the pressure-receiving surface of the pressure medium 52 (the bottom surface of the sliding portion 32 facing the pressure inlet 31c) than the first through-hole 32a, and preferably surrounds the periphery of the pressure-receiving surface of the pressure medium 52. The seal 33 functions to prevent the pressure medium 52 from leaking (pressure leaking) from the pressure-receiving surface of the pressure medium 52 into the gap between the curved surface of the sliding portion 32 and the curved inner wall of the supporting housing 31.

[0062] The seal 34 is disposed between the first and second through-holes 32a and 32b, and preferably between the second through-hole 32b and the second pipe 22. The seal 34 functions to prevent outside air from flowing through the atmosphere-opening port 31d into the first and second pipes 21 and 22 and the first through-hole 32a. The seal 34 is preferably disposed between the first and second through-holes 32a and 32b, closer to the second through-hole 32b. The closer the seal 34 is disposed to the second through-hole 32b, the shorter the period until the first pipe 21 and the atmosphere-opening port 31d are spatially isolated from each other after engine start. This shortens the period during which the pressure detection chamber 2 is open to the atmosphere while the engine is running, thereby improving the pressure detection accuracy of the pressure sensor 11.

[0063] The sealing 35 is, for example, a general O-ring and surrounds the open end of the second pipe 22 inside the support housing 31. The sealing 35 contacts the lower curved surface of the slide portion 32 between the sealings 33 and 34. The sealing 35 serves to seal the gap at the joint between the mounting hole 31b of the support housing 31 and the second pipe 22, thereby maintaining airtightness between the support housing 31 and the second pipe 22. The sealing 35 also serves to seal the gap between the first through-hole 32a and the second pipe 22 when the switch 13 is in the fully on state, thereby maintaining airtightness between the first through-hole 32a and the second pipe 22. The sealing 35 prevents the pressure medium 51 from leaking (pressure leaking) into the gap between the curved surface of the slide portion 32 and the curved inner wall of the support housing 31 when the switch 13 is in the fully on state.

[0064] The first and second retaining portions 36, 39 are disposed within the support housing 31 between the bottom surface of the slide portion 32 facing the atmosphere-opening port 31d and the bottom surface of the support housing 31 on which the atmosphere-opening port 31d is formed. The first retaining portion 36 has a function of constantly applying a physical external force 61 to the slide portion 32, which pushes the slide portion 32 axially back toward the pressure inlet port 31c (second direction). When the switch 13 is off, the first retaining portion 36 pushes the slide portion 32 back to the position closest to the pressure inlet port 31c within the support housing 31 and holds it in that position. The first retaining portion 36 prevents the slide portion 32 from moving toward the atmosphere-opening port 31d (first direction), maintaining the switch 13 in a completely off state. The completely off state of the switch 13 occurs when the engine is stopped and the pressure detection chamber 2 is completely shielded from the pressure medium 51.

[0065] More specifically, the first holding portion 36 is formed of, for example, a general compression coil spring (compression spring), and both ends thereof are fixed (e.g., glued) to the bottom surface of the sliding portion 32 (or the conductive plate 37 described later) and the inner wall of the bottom surface of the supporting housing 31, respectively. The first holding portion 36 constantly generates an external force (pressing load) 61 on the sliding portion 32 in a direction that pushes the sliding portion 32 back toward the pressure inlet 31c. The first holding portion 36 preferably holds the center of the bottom surface of the sliding portion 32 directly (or via the conductive plate 37). This can suppress dispersion of the external force 61 by the first holding portion 36. The inner diameter (diameter) of the coil of the first holding portion 36 may be larger than the diameter of the opening end of the second through hole 32b (e.g., approximately the same as the diameter of the sliding portion 32), so that the opening end of the second through hole 32b exposed on the bottom surface of the sliding portion 32 and the air-opening port 31d of the supporting housing 31 are exposed inside the coil cylinder of the first holding portion 36.

[0066] When the switch 13 is turned on, the first retaining portion 36 contracts due to a compressive load 62 applied by the pressure medium 52 via the sliding portion 32. When the switch 13 is turned off, the first retaining portion 36 returns to its natural length due to the loss of the pressure medium 52, resulting in a repulsive force (elastic force) that pushes the sliding portion 32 back toward the pressure inlet 31c. When the switch 13 is completely turned off, the first retaining portion 36 maintains its natural length (or the state in which its coil length is at its longest) and holds the sliding portion 32 closest to the pressure inlet 31c within the support housing 31. The first retaining portion 36 is only momentarily exposed to exhaust gas 50 flowing out from the second through-hole 32b, but is almost always exposed to the atmosphere. For this reason, the first retaining portion 36 is made of a common material, such as SUS (Steel Special Use Stainless Steel), which is used to make compression coil springs. The first retaining portion 36 is preferably made of a material that is not attracted to the electromagnet 38, which will be described later.

[0067] The second retaining portion 39 has a function of retaining the sliding portion 32 on the atmosphere open port 31d side so that the elastic energy of the first retaining portion 36 does not return the sliding portion 32 to the pressure inlet port 31c side when the switch 13 is in the fully on state. Specifically, the second retaining portion 39 has a function of generating an attractive force 63 that pulls and retains the sliding portion 32, which is pressed toward the atmosphere open port 31d side by the pressure medium 52, toward the atmosphere open port 31d side within the support housing 31. That is, the first retaining portion 36 is maintained in a contracted state by the resultant force of the pressure (compression load 62 on the first retaining portion 36) that presses the sliding portion 32 toward the atmosphere open port 31d side by the pressure medium 52 and the attractive force 63 by the second retaining portion 39. As a result, the sliding portion 32 is retained on the atmosphere open port 31d side, and the fully on state of the switch 13 is always maintained while the engine is running.

[0068] More specifically, the second holding portion 39 is composed of, for example, a conductive plate 37 and a general electromagnet 38. The conductive plate 37 and the electromagnet 38 are disposed apart from the first holding portion 36 and face each other in the axial direction of the sliding portion 32. The conductive plate 37 is disposed (for example, glued) on the bottom surface of the sliding portion 32 on the atmosphere-opening port 31d side. The planar shape of the conductive plate 37 may be any shape that does not cover the open end of the second through hole 32b of the sliding portion 32, and can be appropriately set depending on the position of the open end of the second through hole 32b. For example, the conductive plate 37 may be a circular metal plate having approximately the same diameter as the sliding portion 32 and opening to expose the open end of the second through hole 32b of the sliding portion 32, or may be a substantially rectangular metal plate that covers at least a portion of the bottom surface of the sliding portion 32 on the atmosphere-opening port 31d side.

[0069] The electromagnet 38 is formed by a cylindrical core made of a magnetic material and a coil (not shown) wound around it with a predetermined number of turns. One end of the core is fixed (e.g., glued) to the inner wall of the bottom surface of the support housing 31 on the side of the open-air port 31d so as not to block the open-air port 31d. The other end of the electromagnet 38 faces the conductive plate 37 in the axial direction of the slide portion 32. The coil of the electromagnet 38 is continuously energized by receiving power directly or indirectly from the power supply IC of the ECU when the engine is running. Therefore, the electromagnet 38 constantly generates a magnetic force 64 by receiving power from the power supply IC of the ECU when the engine is running. For example, a wiring for supplying power from the power supply IC of the ECU to the pressure sensor chip 3 may be branched and connected to the coil of the electromagnet 38. The magnetic force 64 of the electromagnet 38 generates an attractive force that attracts the conductive plate 37 toward the electromagnet 38. When the engine is stopped, power supply from the power supply IC of the ECU to the coil of the electromagnet 38 is stopped, and the magnetic force 64 of the electromagnet 38 disappears.

[0070] The attractive force that draws the conductive plate 37 toward the electromagnet 38 (i.e., toward the atmosphere open port 31d) serves as attractive force 63 for holding the sliding portion 32 at a position toward the atmosphere open port 31d. For this reason, the magnetic force 64 of the electromagnet 38 is set to a strength that generates attractive force 63 capable of holding the sliding portion 32 at a predetermined position (a position where the switch 13 is fully on) so that the sliding portion 32, which has been pushed toward the atmosphere open port 31d by the pressure medium 52, is not pushed back toward the pressure introduction port 31c by the external force 61 from the first holding portion 36. When the pressure medium 52 pushes the sliding portion 32 toward the atmosphere open port 31d and the switch 13 is fully on (or approaches a fully on state), and the conductive plate 37 and the electromagnet 38 approach each other to a predetermined distance or less, the conductive plate 37 and the electromagnet 38 attract each other, and the position of the sliding portion 32 is fixed.

[0071] In the switch 13 described above, the slide portion 32 may be provided with only the first through hole 32a, omitting the second through hole 32b. In this case, by not providing the second through hole 32b in the slide portion 32, when the switch 13 is in a completely off state, the pressure detection chamber 2 and the first pipe 21 are sealed by the slide portion 32, and no gas flows into the pressure detection chamber 2. This allows the pressure sensor chip 3 to be shielded from exhaust gas 50 when the switch 13 is in a completely off state (engine stopped). Furthermore, since the pressure detection chamber 2 is not exposed to the outside air even after the engine is stopped, it is also shielded from various external pressure media. When the switch 13 is on, the first through hole 32a in the slide portion 32 is connected between the first and second pipes 21 and 22 as described above, so that the pressure detection chamber 2 and the exhaust pipe 40 are spatially continuous.

[0072] The exhaust pipe 40 is a hollow, cylindrical resin pipe through which exhaust gas (combustion gas) 50 flows during the engine's exhaust stroke. The exhaust pipe 40 connects the engine's cylinder (not shown) to the outside. When the engine is running, the exhaust gas 50 constantly flows from the exhaust pipe 40 into the second pipe 22. When the switch 13 is turned on, the exhaust gas 50 passes through the second pipe 22, the first through-hole 32a of the slide portion 32 of the switch 13, and the first pipe 21 to the pressure detection chamber 2 as a pressure medium 51. When the engine is running, the exhaust gas 50 constantly flows from the second pipe 22 into the third pipe 23 and is transmitted as a pressure medium 52 through the pressure inlet 31c into the support housing 31. An O-ring (not shown) is attached to the outer periphery of the second pipe 22 to seal the gap at the joint between the exhaust pipe 40 and the second pipe 22. This O-ring maintains airtightness between the exhaust pipe 40 and the second pipe 22.

[0073] The operation of the semiconductor package 10 according to the embodiment will now be described. As shown in FIG. 1, when the engine is stopped, no air (oxygen) is introduced into the engine. Therefore, the sliding portion 32 of the switch 13 of the semiconductor package 10 is maintained in a completely off state by receiving only a physical external force 61 (an elastic force of the first holding portion 36 attempting to return to its natural length) from the first holding portion 36. The sliding portion 32 is held by the first holding portion 36 at the position closest to the pressure introduction port 31c within the support housing 31. This maintains a spatially isolated state between the first and second pipes 21 and 22 of the pressure introduction portion 12, and the pressure detection chamber 2 of the pressure sensor 11 and the first pipe 21 are always shielded from exhaust gas 50 when the engine is stopped. In addition, the first pipe 21 and the atmosphere-opening port 31d of the support housing 31 of the switch 13 are maintained in communication via the second through-hole 32b of the sliding portion 32, and the pressure detection chamber 2 is open to the atmosphere via the atmosphere-opening port 31d.

[0074] Outside air (atmosphere) flows into the pressure detection chamber 2 through the atmosphere opening 31d, replacing the gas in the pressure detection chamber 2 with outside air. As described below, exhaust gas 50 that flows into the pressure detection chamber 2 while the engine is running can be released to the outside when the engine is stopped. The two-way gas flow through the first pipe 21 and the second through-hole 32b is indicated by double-headed arrows 71. The second through-hole 32b of the slide portion 32 and the portion of the support housing 31 closer to the atmosphere opening 31d than the slide portion 32 are always exposed to the atmosphere regardless of the vehicle's operating status (whether the engine is running or not). The exhaust pipe 40 and the second and third pipes 22 and 23 of the pressure introducing portion 12 are always airtight and exposed to the exhaust gas 50 in the exhaust pipe 40 regardless of the vehicle's operating status. When the engine is stopped, the first through-hole 32a of the slide portion 32 may be exposed to the exhaust gas 50 accumulating in the exhaust pipe 40, or may be open to the atmosphere via the first pipe 21.

[0075] Meanwhile, as shown in FIG. 6, when the engine is running, air is drawn into the engine. Combustion gases generated in the engine's cylinders during the combustion and expansion strokes of the engine flow into the exhaust pipe 40 as exhaust gas 50 during the exhaust stroke. The arrows on the exhaust gas 50 indicate the flow direction of the exhaust gas 50. A portion of the exhaust gas 50 flows from the exhaust pipe 40 into the second pipe 22 of the pressure introducing unit 12 as a pressure medium 51. A branch of the exhaust gas 50 that flows into the second pipe 22 flows into the third pipe 23 of the pressure introducing unit 12 and is transmitted as a pressure medium 52 from the pressure introducing port 31c into the support housing 31 of the switch 13. The third pipe 23 and the portion of the slide unit 32 in the support housing 31 closer to the pressure introducing port 31c than the slide unit 32 are kept airtight by the sealing 33. When pressure from the pressure medium 52 is applied to the pressure-receiving surface of the slide unit 32 (the bottom surface facing the pressure introducing port 31c), the switch 13 is turned on.

[0076] When the switch 13 is turned on, the sliding portion 32 receives pressure from the pressure medium 52 and moves (slides) within the support housing 31 toward the atmosphere-opening port 31d. This causes the first pipe 21 and the first through-hole 32a of the sliding portion 32 to begin communicating with each other. The two-way gas flow through the first pipe 21 and the first through-hole 32a is indicated by a double-headed arrow 72. At this time, the first pipe 21 may be in communication with the second through-hole 32b of the sliding portion 32, or the first through-hole 32a of the sliding portion 32 may be spatially continuous with the atmosphere-opening port 31d. The second pipe 22 is still disconnected from the first through-hole 32a of the sliding portion 32. As shown in FIG. 7, when the sliding portion 32 is further pushed toward the atmosphere-opening port 31d by the pressure medium 52, the first pipe 21 and the second through-hole 32b of the sliding portion 32 are spatially disconnected from each other. The pressure detection chamber 2, the first pipe 21 and the first through-hole 32a are sealed by the sealings 33 and 34, and are also shielded from the atmosphere by the sealing 34.

[0077] As shown in FIG. 8 , when the slide portion 32 is further pushed toward the atmosphere-opening port 31d by the pressure medium 52, the second pipe 22 begins to communicate with the first through-hole 32a of the slide portion 32. This connects the exhaust pipe 40 to the pressure detection chamber 2, and a portion of the exhaust gas 50 begins to be transmitted to the pressure detection chamber 2 as the pressure medium 51 via the second pipe 22 and the first through-hole 32a. The two-way gas flow through the second pipe 22 and the first through-hole 32a is indicated by double-headed arrows 73. As shown in FIG. 9 , when the slide portion 32 is pushed toward the atmosphere-opening port 31d until the first through-hole 32a of the slide portion 32 completely connects the first and second pipes 21 and 22, the switch 13 is fully turned on. The gap between the second pipe 22 and the first through-hole 32a of the slide portion 32 is sealed with a sealant 35. Thereafter, the slide portion 32 continues to be held by the second holding portion 39 at a position where the first and second pipes 21, 22 are completely connected to each other while the engine is running.

[0078] When the switch 13 is in a fully on state, the path of the pressure medium 51 (the path from the exhaust pipe 40 to the pressure detection chamber 2) is always spatially continuous, and the pressure sensor chip 3 is not shielded from the exhaust gas 50. In addition, the airtightness of the path of the pressure medium 51 from the exhaust pipe 40 to the pressure detection chamber 2 is maintained by an O-ring that seals the gap between the exhaust pipe 40 and the second piping 22 and by seals 33 to 35 inside the support housing 31. Therefore, the pressure medium 51 that flows from the exhaust pipe 40 into the pressure introducing portion 12 flows inside the pressure introducing portion 12 and is transmitted to the pressure sensor chip 3 without leaking to the outside. The pressure sensor 11 outputs the amount of change in the resistance value of the strain gauge, which changes in response to the pressure from the pressure medium 51 applied to the diaphragm 3a of the pressure sensor chip 3, as an electrical signal to an external circuit. The first holding portion 36 receives a compressive load (resultant force of the compressive load 62 and the attractive force 63) from the pressure medium 52 and the second holding portion 39 via the slide portion 32 and is maintained in the most compressed state when the switch 13 is in the completely on state.

[0079] When the vehicle stops, the intake of air into the engine stops, causing exhaust gas 50 to accumulate in the exhaust pipe 40. The cessation of the flow of exhaust gas 50 causes the pressure medium 52 to disappear, eliminating the external force pushing the sliding portion 32 toward the atmosphere-opening port 31d, and turning off the switch 13. Power supply to the second holding portion 39 is also stopped, eliminating the magnetic force 64 of the electromagnet 38 of the second holding portion 39 and the attractive force 63 pulling the sliding portion 32 toward the atmosphere-opening port 31d. Since the first holding portion 36 is no longer subjected to the compressive load 62 from the pressure medium 52, it attempts to return to its natural length, pushing the sliding portion 32 back toward the pressure inlet port 31c and holding it closest to the pressure inlet port 31c within the support housing 31. This maintains the switch 13 in a completely off state. Therefore, as described above, the pressure detection chamber 2 is shielded from the exhaust gas 50 and opened to the atmosphere, and the air in the pressure detection chamber 2 is replaced with outside air.

[0080] As described above, according to the embodiment, the pressure introduction section is a pipe for transmitting exhaust gas flowing in from the exhaust pipe to the pressure detection chamber as a pressure medium, and includes a switch that moves and opens and closes (on / off) in response to a physical external force. When the switch is in the on state, it spatially connects the exhaust pipe and the pressure detection chamber via the pressure introduction section, and when in the off state, it spatially separates the exhaust pipe and the pressure detection chamber. When the switch is in the off state, the pressure detection chamber can be shielded from the high-temperature, high-humidity exhaust gas in the exhaust pipe, thereby suppressing deterioration of the pressure sensor chip and its components due to rust, corrosion, hygroscopic expansion, and the like. Furthermore, according to the embodiment, the switch has an atmosphere vent that allows outside air to enter the pressure detection chamber when in the off state. When the switch is in the off state, the pressure detection chamber can be opened to the atmosphere and exposed to the atmosphere, thereby significantly reducing deterioration of the pressure sensor chip and its components.

[0081] Furthermore, according to the embodiment, the on / off state of the switch can be easily realized physically by operating and stopping the engine (i.e., generating and discharging the pressure medium), using the simple slide mechanism of the switch, the elastic force of the spring, and the magnetic force of the electromagnet. Furthermore, since the switch is maintained in a completely on state by the magnetic force of the electromagnet, it is possible to maintain a spatial connection between the exhaust pipe and the pressure detection chamber even if the flow of pressure medium into the pressure introduction portion stops while the engine is running.

[0082] The present disclosure is not limited to the above-described embodiment, and various modifications are possible within the scope of the present disclosure. For example, a switch and second and third pipes of the pressure introducing portion of the present disclosure may be added to a semiconductor package including a pressure sensor and a pressure introducing portion (corresponding to the first pipe) as in the reference example. [Industrial Applicability]

[0083] As described above, the semiconductor package according to the present disclosure is useful as an automotive semiconductor package for pressure measurement purposes attached to the piping of an internal combustion engine (engine), and is particularly suitable for attaching to the piping (exhaust pipe) of an exhaust system to measure exhaust pressure. [Explanation of symbols]

[0084] 1,101 cases 2 Pressure detection chamber 2a Pressure detection chamber recess 2b Pressure inlet of pressure detection chamber 3 Pressure sensor chip 3a Pressure sensor chip diaphragm 3b Recess on the back of the pressure sensor chip 4 Lead Frame 5 Bonding Wire 6 Base member 7. Adhesive 8 Sensor mounting part of the container body 8a Bottom of the sensor mounting area 9 Pressure sensor chip storage container body 10,110 Semiconductor packages 11,111 Pressure Sensor 12,112 Pressure introduction section 13 Switch 21~23 Piping 31 Switch support housing 31a, 31b Mounting holes for piping the switch 31c Pressure inlet of switch support housing 31d Switch support housing atmospheric vent 32 Switch slide 32a, 32b Through holes in slide section 33~35 Ceiling 36,39 Switch slide retainer 37 Conductive plate 38 Electromagnet 40,120 Exhaust pipe 40a Mounting hole for exhaust pipe installation 50,130 Exhaust gas 51, 52, 131 Pressure medium

Claims

1. A semiconductor package for detecting the pressure of gas flowing through an engine pipe, a pressure sensor chip that converts the pressure received from the first pressure medium into an electrical signal; a pressure detection chamber that accommodates the pressure sensor chip and to which the first pressure medium is transmitted; a pressure introduction portion disposed between the engine pipe and the pressure detection chamber, into which the gas serving as the first pressure medium flows from the engine pipe; Equipped with the pressure introducing section has a switch that moves and opens and closes in response to a physical external force, The switch is In an open state, the engine piping and the pressure detection chamber are spatially connected via the pressure introduction portion, A semiconductor package characterized in that, in a closed state, the engine piping and the pressure detection chamber are spatially separated.

2. 2. The semiconductor package according to claim 1, wherein the switch is moved in a first direction to an open state when pressure is applied by a second pressure medium that is a branch of the first pressure medium.

3. The switch is a first holding portion that suppresses movement of the switch in the first direction; 3. The semiconductor package according to claim 2, wherein when the second pressure medium disappears, the first holding portion pushes the semiconductor package back in a second direction opposite to the first direction, thereby bringing the semiconductor package into a closed state.

4. the first holding portion is a compression coil spring that generates a pressing load that presses the switch back in the second direction, 4. The semiconductor package according to claim 3, wherein the switch is constantly subjected to the pressing load exerted by the first holding portion.

5. The semiconductor package according to claim 4 , wherein the switch is maintained in a closed state by the pressing load applied by the first holding portion.

6. The switch is a second holding portion that attracts and holds the switch in the first direction; 3. The semiconductor package according to claim 2, wherein when the semiconductor package is moved in the first direction to an open state, or when the semiconductor package is moved in the first direction to approach an open state, the semiconductor package is held by the second holding portion and maintains the open state.

7. The semiconductor package according to claim 6 , wherein the second holding portion has an electromagnet that generates an attractive force that attracts the switch in the first direction.

8. 8. The semiconductor package according to claim 7, wherein the second holding portion attracts and holds the switch by the attractive force when the switch, which has moved in the first direction, approaches the electromagnet within a predetermined distance.

9. 8. The semiconductor package according to claim 7, wherein power is supplied to the coil of the electromagnet and to the pressure sensor chip from the same power source.

10. 2. The semiconductor package according to claim 1, wherein the switch has an air vent, and when closed, the switch spatially connects the pressure detection chamber to the outside via the air vent.

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