Pressure sensor

Abstract

Pressure sensor which features: a sensor chip (21) that detects the pressure of a printing medium, and a housing (30) that accommodates the sensor chip (21) and has an inlet port (33) connected to an outer surface, wherein the housing (30) further comprises a pressure inlet section (35) surrounding the inlet port (33), wherein: the pressure inlet section (35) is configured from: a front wall (35a) located in front of the inlet port (33) to face the inlet port (33) with a space between it and the inlet port (33), an upper wall (35b) and a pair of side walls (35c and 35d), each connected to the front wall (35a), and an opening (35e) which introduces the pressure medium into the inlet port (33) from a lower position relative to the inlet port (33), wherein the upper wall (35b) is connected to the side walls (35c and 35d) and is angled as a whole to an upper position in relation to the inlet connection (33) in order to protrude, the front wall (35a) has an opening end (35f) that forms the opening (35e), the opening end (35f) being recessed in an arc shape towards the upper wall (35b), which causes the front wall (35a) to be angled towards the side walls (35c and 35d), the upper wall (35b) and the side walls (35c and 35d) have a groove (35k), the side walls (35c and 35d) have a first side wall (35c) and a second side wall (35d), and the groove (35k) connects an opening end (35g) of the first side wall (35c) and an opening end (35h) of the second side wall (35d) via the first side wall (35c), the upper wall (35b) and the second side wall (35d).

Description

Technical area

[0001] The present disclosure relates to a pressure sensor used in a waterlogged environment. State of the art

[0002] A conventional type of pressure sensor with structures that prevent the ingress of foreign materials is known, for example, from US Pat. No. 7,380,458 B1. More specifically, a structure was proposed that includes a pressure sensing element placed in a housing having a port through which a pressure medium is fed to the pressure sensing element.

[0003] The connector protrudes from the outer wall of the housing. The connector has an opening that opens toward the bottom of the connector and a path through which the pressure medium is introduced into the interior of the housing through the opening. This means that the connector has a structure similar to a shield. The top end of the connector is flat, and an opening end that defines the opening is also flat.

[0004] The inventors of the present application have discovered the following: The conventional technique can allow water to collect when the upper end is exposed to water because the upper end of the connector is flat. Water can flow from the upper end along the outer wall of the connector and freeze into ice. The ice can freeze into an icicle, which can block the opening of the connector.

[0005] Additionally, because the opening is flat, water tends to remain at the opening end of the connector instead of flowing away from it. The water remaining at the opening end can freeze into ice, which can grow into an icicle. The icicle can block the opening of the connector.

[0006] Furthermore, a sensor device, in particular for use in a motor vehicle, is known from DE 10 2011 079 446 A1. The sensor device has a housing for accommodating a sensor element, wherein the sensor element has electrical contact surfaces that are electrically conductively connected to electrical plug connections arranged in the housing in the region of contact contacts of the plug connections. The sensor element is subjected to a force from a housing element in the direction of the plug connections for electrical contacting. The electrical plug connections are arranged in a fixed position in the housing in the region of the contact contacts with the electrical contact surfaces of the sensor element. A support is formed between the sensor element and the housing such that the sensor element has a three-point contact in the housing. Brief description of the invention

[0007] It is an object of the present disclosure to provide a structure that minimizes the possibility of water remaining at a pressure inlet portion of a housing in a pressure sensor used in a waterlogged environment.

[0008] The object is achieved by a pressure sensor according to claims 1, 7, 8, and 9. Advantageous further developments are the subject of the subclaims.

[0009] In the pressure sensor according to the invention, the top wall of the pressure inlet port is angled so that when the top wall is exposed to water, this structure can facilitate water flow toward a side wall. Additionally, the opening end of the front wall is angled so that when the front wall is exposed to water, the structure can facilitate water flow toward the side wall. Thus, the present disclosure can minimize the possibility of water remaining at the pressure inlet port, preventing the opening from becoming blocked due to water freezing. Short description of the drawings

[0010] The above and other aspects, features, and advantages of the present disclosure will become more apparent from the following detailed description with reference to the accompanying drawings. In the drawings: Fig. 1 is a sectional view of a pressure sensor according to a first embodiment, Fig. 2 a front view of the pressure sensor according to the first embodiment, Fig. 3 a front view of the pressure sensor according to a second embodiment, Fig. 4 a sectional view of the pressure sensor according to the second embodiment, Fig. 5 is a perspective view of a pressure sensor according to a third embodiment, Fig. 6 is a perspective view of a pressure sensor according to a fourth embodiment, Fig. 7 is a front view of a pressure sensor according to a fifth embodiment, Fig. 8 is a front view of a pressure sensor according to a sixth embodiment, and Fig. 9 is a sectional view of the pressure sensor according to the sixth embodiment. Preferred embodiments for carrying out the invention

[0011] Embodiments of the present disclosure are described below with reference to the drawings. Identical or similar components in the embodiments are denoted by identical symbols in the drawings. The first and second embodiments serve to understand the present invention, which is embodied in the subsequent embodiments. (First embodiment)

[0012] A first embodiment will be described with reference to the drawings. A pressure sensor according to the present embodiment is used in a water-soaked environment. The pressure sensor is housed in a door of a vehicle and designed as a side impact detection sensor that detects a side impact into the door. The pressure sensor is secured to an inner panel located inside the door of the vehicle. A pressure detection result by the pressure sensor is used to activate an occupant protection device, such as an airbag. A pressure sensor 10 as described above includes a pressure detection section 20 and a housing 30 as shown in FIG. Fig. 1 is shown.

[0013] The pressure sensing section 20 corresponds to a pressure sensing device designed to detect the pressure of a pressure medium inside a door when the pressure changes according to a side impact applied to the door. The pressure sensing section 20 includes a sensor chip 21, a circuit board 22, a frame 23, and a protective material 24.

[0014] The sensor chip 21 is a semiconductor chip designed to detect the pressure of the pressure medium. The sensor chip 21 includes a semiconductor substrate with a partially reduced thickness and a diaphragm for pressure detection. The diaphragm has a pressure-receiving surface to which the pressure of the pressure medium is applied. Several measuring resistors (not shown) are arranged on the diaphragm to form a Wheatstone bridge circuit. According to this configuration, the sensor chip 21 utilizes the piezoresistance effect of each measuring resistor and detects a voltage based on the strain in the diaphragm as a pressure.

[0015] The sensor chip 21 is attached to a base, for example, so that a vacuum pressure reference chamber is formed in a space between the sensor chip 21 and the base. This means that the sensor chip 21 detects the absolute pressure. Since the sensor chip 21 is attached to the base as described above, the base is actually secured to the circuit board 22 with, for example, an adhesive.

[0016] The circuit board is a layered board with contact elements (not shown) and wiring patterns (not shown) made of gold or the like. The circuit board 22 is a ceramic multilayer board, which is a stack of ceramic plates. The circuit board 22 may be a printed circuit board. In the present embodiment, the circuit board 22 has one surface on which the sensor chip 21 is mounted and another surface on which an electronic component 25, such as a chip capacitor, is mounted.

[0017] The frame 23 is a component that covers the sensor chip 21 with the protective material 24. The frame 23 is shaped into a hollow cylinder and made of a material such as resin. The frame 23 is open at both ends of the cylinder. One of the open ends of the frame 23, adjacent to one surface of the circuit board 22, is fixed to the circuit board 22. In this way, the sensor chip 21 is located in the hollow part of the frame 23.

[0018] The protective material 24 covers the sensor chip 21, a bonding wire (not shown), and a connection between contact elements (not shown) and the bonding wire for the protection. The protective material 24 is located in the hollow part of the frame 23. Thus, the pressure of the pressure medium is applied from the outside to the protective material 24 and absorbed by the membrane via the protective material 24 for detection by the sensor chip 21.

[0019] The protective material 24 may be a fluorogel, a silicone gel, a fluorosilicone gel, or the like. The protective material 24 may be used to prevent physical damage to the binding wire, corrosion of the contact elements, and the ingress of foreign materials.

[0020] The housing 30 corresponds to the housing device that houses the sensor chip 21 and forms part of an external view of the pressure sensor. The housing 30 is formed by molding resin. More specifically, the housing 30 includes a housing chamber 31, a port 32, an inlet port 33, a pressure inlet path 34, and a pressure inlet section 35.

[0021] The pressure sensing section 20 is housed in the accommodation chamber 31. In the present embodiment, the accommodation chamber 31, which is hollow within the housing 30, has a recess 36 formed by depressing or lowering a portion of the housing 30 toward the bottom. The pressure sensing section 20 is fixed to the bottom of the recess 36. The recess 36 is closed by a lid 37 to define the hollow accommodation chamber 31.

[0022] The terminal 32 is a connecting part that electrically connects the sensor chip 21 to an external device. The terminal 32 is insert-molded into the housing 30 so that one end of the terminal 32 is exposed in the housing chamber 31, and the other end of the terminal 32 is exposed in a connector portion 38 provided remote from the housing chamber 31. For example, three terminals 32 are provided in the housing 30 for power, ground, and signal.

[0023] The inlet port 33 guides the pressure medium to the interior of the housing 30 and communicates with the pressure inlet path 34. The pressure inlet path 34 connects the inlet port 33 to the accommodation chamber 31. The pressure inlet path 34 is formed, for example, in an L-shape.

[0024] The pressure inlet section 35 surrounds the inlet port 33 and supplies the pressure medium into the inlet port 33 from the outside. As shown in Fig. 2, the pressure inlet section 35 has a front wall 35a, a top wall 35b and a pair of side walls 35c and 35d.

[0025] As it is in Fig. As shown in Figure 1, the front wall 35a is a planar component located in front of the housing 30 with a gap therebetween. More specifically, the front wall 35a is located in front of the inlet port 33 so as to face the inlet port 33 with a gap therebetween.

[0026] The top wall 35b and the side walls 35c and 35d correspond to a wall section that forms a part of the housing 30 facing forward. The top wall 35b and the side walls 35c and 35d are connected to the front wall 35a. This arrangement forms an opening 35e for supplying the pressure medium into the inlet port 33 from a lower position relative to the housing 30. That is, the front wall 35a, the top wall 35b, and the side walls 35c and 35d form an umbrella-like structure.

[0027] In the structure described above, the front wall 35a has an opening end 35f forming the opening 35e, as shown in Fig. 2. The opening end 35f is recessed toward the top wall 35b in an arc shape to be angled toward the side walls 35c and 35d. That is, the entire opening end 35f is angled except for portions where the front wall 35a is connected to the side walls 35c and 35d. In other words, the opening end 35f of the front wall 35a is non-linear at a portion constituting a lower portion of the inlet port 33. Thus, when the front wall 35a is exposed to water, the opening end 35f of the front wall 35a, which is angled as described above, can facilitate water flow toward the side walls 35c and 35d.

[0028] Furthermore, the upper wall 35b, which is connected to the side walls 35c and 35d, is angled in its entirety to protrude to an upper position relative to the inlet port 33. In the present embodiment, the upper wall 35b is angled in an arc shape. That is, the entire upper wall 35b is angled. In other words, the upper wall 35b is not flat at a portion corresponding to an upper portion of the inlet port 33. Thus, when the upper wall 35a of the pressure inlet port 35 is exposed to water, the upper wall 35b angled as described above can facilitate water flow toward the side walls 35c and 35d.

[0029] The overall structure of the pressure sensor 10 according to the present embodiment is as described above. As shown in Fig. 1, the housing 30 has a projecting portion 39 and a mounting portion 40 on the side opposite the inlet port 33.

[0030] The inner panel of a vehicle door has through holes corresponding to the protruding portion 39 and the fixing portion 40. The protruding portion 39 and the fixing portion 40 of the housing 30 are inserted into the through holes and fixed therein. With the inner panel as a reference, the opening 35e of the housing 30 is adjacent to an outer panel of the door, and the housing 30 is adjacent to a cabin of the vehicle.

[0031] In the event of an impact on the door, the pressure in the space between the inner and outer plates of the door changes with the impact. That is, the gas present in the space between the inner and outer plates of the door, which serves as the pressure medium, is introduced into the accommodation chamber 31 via the opening 35e, the inlet port 33, and the pressure inlet path 34 of the housing 30. The sensor chip 21 then detects a pressure.

[0032] As previously described, in the present embodiment, the opening end 35f of the front wall 35a, which forms the pressure inlet port, is angled. The upper wall 35b is also angled. These features can provide a structure that minimizes the possibility of water remaining at the opening end 35f of the front wall 35a and on the upper wall 35b. This structure can also drain water in a predetermined direction before water freezes. Thus, the structure can minimize the possibility of blocking the opening 35e even if water that has fallen onto the pressure inlet portion 35 freezes into an icicle. Thus, the structure can prevent an icicle from growing at the opening 35e of the pressure inlet portion 35. (Second embodiment)

[0033] Differences between the present embodiment and the first embodiment will be described below. As in Fig. 3, side walls 35c and 35d have opening ends 35g and 35h, respectively. The opening ends 35g and 35h form an opening 35e of a pressure inlet section 35. The opening ends 35g and 35h have slopes 35i and 35j, respectively. As shown in Fig. 4, the slopes 35i and 35j are provided in a housing 30 and are arranged at an angle from a front wall 35a to an outer wall surface of the housing 30.

[0034] The opening ends 35g and 35h of the side walls 35c and 35d, which are inclined as described above, can facilitate the flow of water that has fallen onto the side walls 35c and 35d on the slopes 35i and 35j. Drainage from the side walls 35c and 35d is thus improved, which can prevent an icicle from growing at the opening 35e of the pressure inlet section 35. (Third embodiment)

[0035] Differences between the present embodiment and the first to second embodiments will be described below. As shown in Fig. As shown in Figure 5, a pressure inlet portion 35 has a groove 35k. Specifically, the groove 35k starts at the opening end 35g of one side wall 35c and extends within the side wall 35c, a top wall 35b, and another side wall 35d, ending at an opening end 35h of the other side wall 35d. The groove 35k is continuously formed in the top wall 35b and the side walls 35c and 35d. One side wall 35c corresponds to a first side wall, and the other side wall 35d corresponds to a second side wall.

[0036] With this structure, water that has fallen onto the pressure inlet portion 35 tends to enter the groove 35k due to capillary action. Thus, water that has fallen onto the top wall 35 and the side walls 35c and 35d can be caused to flow into the groove 35k by the action of capillary action. This structure can prevent an icicle from growing at an opening 35e of the pressure inlet portion 35.

[0037] A plurality of grooves 35k may be formed parallel to one another. The grooves 35k may provide improved drainage. (Fourth embodiment)

[0038] Differences between the present embodiments and the first to third embodiments will be described below. As shown in Fig. As shown in Figure 6, a front wall 35a has a three-dimensional structure. Specifically, the front wall 35a has a central portion between one side wall 35c and another side wall 35d, and the central portion protrudes from the side walls 35c and 35d. That is, the central portion of the front wall 35a sticks farther than the side walls 35c and 35d. Thus, an outer wall surface 35l of the front wall 35a is angled from the central portion to the side walls 35c and 35d.

[0039] Thus, water that has fallen onto the front wall 35a can be drained toward the side walls 35c and 35d with increased ease. This structure can minimize the possibility of water adhering to the opening end 35f of the front wall 35a, thereby preventing an icicle from growing at an opening 35e of a pressure inlet portion 35. (Fifth embodiment)

[0040] Differences between the present embodiments and the first to fourth embodiments will be described below. As shown in Fig. As shown in Figure 7, a top wall 35b has a flat portion adjacent to one side wall 35c and another flat portion adjacent to the other side wall 35d. The portion adjacent to one side wall 35c is connected to the portion adjacent to the other side wall 35d at an acute angle. A front wall 35a has an upper portion with a triangular shape corresponding to the shape of the top wall 35b. The top wall 35b is connected to the side walls 35c and 35d at an obtuse angle.

[0041] The upper wall 35b with the flat sections as described above provides angles that are steeper than those of a curved shape of the upper wall 35b and can thereby provide improved drainage for water that has fallen onto the upper wall 35b. (Sixth embodiment)

[0042] Differences between the present embodiment and the first to fifth embodiments will be described below. As shown in Fig. 8, a front wall 35a has a sight glass 35m adjacent to an opening end 35f of an outer wall surface 35l of the front wall 35a. As shown in Fig. As shown in Figure 9, the sight glass 35m is a projecting portion of the outer wall surface 35l of the front wall 35a. The sight glass 35m is angled toward its end.

[0043] With this structure, water that has fallen onto the front wall 35a flows along the outer wall surface 35l to drip from the end of the sight glass 35m; thus, the structure can direct the water flow away from an opening 35e. Thus, the structure can prevent an icicle from growing at the opening 35e of a pressure inlet section 35. (Other embodiment)

[0044] The structures of the pressure sensor 10 in the above-described embodiments are presented as examples and are not intended to be limiting. Other structures may be used to achieve the present disclosure. For example, the structures in the above-described embodiments may be combined as needed.

[0045] In addition, the locations and the like of the accommodation chamber 31, the pressure inlet path 34, and the inlet port 33 in the housing 30 are shown as examples and can be changed as needed. Furthermore, other factors, such as the structure within the accommodation chamber 31 and the route of the pressure inlet path 34, can be designed as appropriate according to the mounting method of the pressure sensor 10. Of course, the structure of the pressure sensing section 20 including the sensor chip 21 is not limited to the above-described embodiments and can be changed to other structures.

[0046] For example, in the exemplary embodiments, the term "lower" indicates the direction of gravity, and the term "upper" indicates the opposite direction. The term "front" indicates the direction perpendicular to the direction indicated by the term "lower" and toward the side where the inlet port is located in the housing.

[0047] While various embodiments, configurations, and aspects of the pressure sensor have been exemplified, the embodiments, configurations, and aspects of the pressure sensor are not limited to those described above. For example, the embodiments, configurations, and aspects obtained from the appropriate combination of technical elements disclosed in various embodiments, configurations, and aspects are also within the scope of the embodiments, configurations, and aspects of the pressure sensor.

Claims

[1] Pressure sensor having: a sensor chip (21) which detects a pressure of a printing medium, and a housing (30) accommodating the sensor chip (21) and having an inlet port (33) connected to an outside, the housing (30) further having a pressure inlet portion (35) surrounding the inlet port (33), wherein: the pressure inlet section (35) is configured from: a front wall (35a) located in front of the inlet port (33) to face the inlet port (33) with a gap from the inlet port (33), a top wall (35b) and a pair of side walls (35c and 35d), each connected to the front wall (35a), and an opening (35e) which introduces the pressure medium into the inlet port (33) from a lower position with respect to the inlet port (33), wherein the upper wall (35b) is connected to the side walls (35c and 35d) and is angled as a whole to an upper position with respect to the inlet port (33) to protrude, the front wall (35a) has an opening end (35f) forming the opening (35e), the opening end (35f) being recessed in an arcuate shape towards the top wall (35b), causing the front wall (35a) to be angled towards the side walls (35c and 35d), the upper wall (35b) and the side walls (35c and 35d) have a groove (35k), the side walls (35c and 35d) have a first side wall (35c) and a second side wall (35d), and the groove (35k) connects an opening end (35g) of the first side wall (35c) and an opening end (35h) of the second side wall (35d) via the first side wall (35c), the upper wall (35b) and the second side wall (35d). [2] Pressure sensor according to claim 1, wherein each of the side walls (35c and 35d) has an opening end (35g and 35h) that configures the opening (35e), and each of the opening ends (35g and 35h) has an inclination (35i and 35j) which the front wall (35a) is angled towards the housing (30). [3] Pressure sensor according to claim 1 or 2, wherein: the front wall (35a) has a middle section between the first side wall (35c) and the second side wall (35d), the front wall (35a) has an outer wall surface (35l), and the middle section protrudes from the side walls (35c and 35d) and the outer wall surface (35l) is angled. [4] Pressure sensor according to one of claims 1 to 3, wherein: the upper wall (35b) has a first planar portion adjacent to the first side wall (35c) and a second planar portion adjacent to the second side wall (35d), and the first planar portion adjacent to the first side wall (35c) is connected to the second planar portion adjacent to the second side wall (35d) at an acute angle. [5] Pressure sensor according to one of claims 1 to 4, wherein the front wall (35a) has a sight glass (35m) adjacent to the opening end (35f) on an outer wall surface (35l) of the front wall (35a), and the outer wall surface (35l) protrudes and provides the sight glass (35m). [6] Pressure sensor according to one of claims 1 to 5, wherein an expression “lower” indicates a direction of gravity, an expression “upper” indicates a direction opposite to the direction indicated by the expression “lower” and a term "front" indicates a direction perpendicular to the direction indicated by the term "lower" and toward a side where the inlet port (33) is located in the housing (30). [7] Pressure sensor comprising: a sensor chip (21) which detects a pressure of a printing medium, and a housing (30) accommodating the sensor chip (21) and having an inlet port (33) connected to an outside, the housing (30) further having a pressure inlet portion (35) surrounding the inlet port (33), wherein: the pressure inlet section (35) is configured from: a front wall (35a) located in front of the inlet port (33) to face the inlet port (33) with a gap from the inlet port (33), a top wall (35b) and a pair of side walls (35c and 35d), each connected to the front wall (35a), and an opening (35e) which introduces the pressure medium into the inlet port (33) from a lower position with respect to the inlet port (33), wherein the upper wall (35b) is connected to the side walls (35c and 35d) and is angled as a whole to an upper position with respect to the inlet port (33) to protrude, the front wall (35a) has an opening end (35f) forming the opening (35e), the opening end (35f) being recessed in an arcuate shape towards the top wall (35b), causing the front wall (35a) to be angled towards the side walls (35c and 35d), the front wall (35a) has a central section between a first side wall (35c) and a second side wall (35d), the front wall (35a) has an outer wall surface (35l), and the middle section protrudes from the side walls (35c and 35d) and the outer wall surface (35l) is angled. [8] Pressure sensor comprising: a sensor chip (21) which detects a pressure of a printing medium, and a housing (30) accommodating the sensor chip (21) and having an inlet port (33) connected to an outside, the housing (30) further having a pressure inlet portion (35) surrounding the inlet port (33), wherein: the pressure inlet section (35) is configured from: a front wall (35a) located in front of the inlet port (33) to face the inlet port (33) with a gap from the inlet port (33), a top wall (35b) and a pair of side walls (35c and 35d), each connected to the front wall (35a), and an opening (35e) which introduces the pressure medium into the inlet port (33) from a lower position with respect to the inlet port (33), wherein the upper wall (35b) is connected to the side walls (35c and 35d) and is angled as a whole to an upper position with respect to the inlet port (33) to protrude, the front wall (35a) has an opening end (35f) forming the opening (35e), the opening end (35f) being recessed in an arcuate shape towards the top wall (35b), causing the front wall (35a) to be angled towards the side walls (35c and 35d), the upper wall (35b) has a first planar portion adjacent to a first side wall (35c) and a second planar portion adjacent to a second side wall (35d), and the first planar portion adjacent to the first side wall (35c) is connected to the second planar portion adjacent to the second side wall (35d) at an acute angle. [9] Pressure sensor comprising: a sensor chip (21) which detects a pressure of a printing medium, and a housing (30) accommodating the sensor chip (21) and having an inlet port (33) connected to an outside, the housing (30) further having a pressure inlet portion (35) surrounding the inlet port (33), wherein: the pressure inlet section (35) is configured from: a front wall (35a) located in front of the inlet port (33) to face the inlet port (33) with a gap from the inlet port (33), a top wall (35b) and a pair of side walls (35c and 35d), each connected to the front wall (35a), and an opening (35e) which introduces the pressure medium into the inlet port (33) from a lower position with respect to the inlet port (33), wherein the upper wall (35b) is connected to the side walls (35c and 35d) and is angled as a whole to an upper position with respect to the inlet port (33) to protrude, the front wall (35a) has an opening end (35f) forming the opening (35e), the opening end (35f) being recessed in an arcuate shape towards the top wall (35b), causing the front wall (35a) to be angled towards the side walls (35c and 35d), the front wall (35a) has a sight glass (35m) adjacent to the opening end (35f) on an outer wall surface (35l) of the front wall (35a), and the outer wall surface (35l) protrudes and provides the sight glass (35m).

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