JP7384635B2 - fluid sensor - Google Patents

Description

FIELD OF THE INVENTION The present invention relates to fluid sensors.

Plug-in sensors are known that measure the pressure and temperature of a fluid medium used in a refrigerant circuit of an automobile air conditioner. The plug-in sensor has a sensor body with a sensor shaft and a pressure sensor arranged substantially concentrically on the sensor body.

Furthermore, the sensor body is provided with a through hole for connecting the pressure sensor with the fluid medium and a temperature sensor hole in which the temperature sensor is accommodated. The temperature sensor hole has a temperature sensor hole axis which is inclined towards the end of the sensor shaft facing the flowing medium.

Patent No. 5222295

By the way, in conventional sensors, a long and narrow hole is formed diagonally in the sensor body (casing) made of metal, and a lead-type thermistor is installed in this hole. Therefore, the response when measuring the heat transmitted through the thin part of the casing made of metal is improved. However, it is difficult to drill holes in the metal casing, and installation of the thermistor into the drilled holes becomes cumbersome, making the manufacturing process complicated.

An object of the present invention is to provide a fluid sensor that has good responsiveness when measuring the temperature of a fluid to be measured and is easy to manufacture.

A fluid sensor according to an aspect of the present invention includes a casing into which a fluid to be measured enters, and a material with high thermal conductivity, and a first surface on one side of which the fluid to be measured enters the casing. a heat transfer material that is provided in the housing so as to be in contact with the fluid and that transfers heat entering from the first surface toward a second surface on the other side by thermal conduction; a heat transfer material support made of a thin material, supporting the heat transfer material by engaging with the heat transfer material on a second surface side of the heat transfer material, and installed in the housing; The heat transfer material support is made of a material with high thermal conductivity, and is provided on the heat transfer material support, from a first surface on one side of the heat transfer material support to a first surface on the other side of the heat transfer material support. A heat conduction part that transfers heat by heat conduction in a direction toward the second surface, and a temperature measurement part that measures the temperature of the fluid to be measured by measuring the temperature of the heat transmitted through the heat conduction part. .

Further, in the fluid sensor according to an aspect of the present invention, the heat transfer material support has a through hole that penetrates from the first surface of the heat transfer material support to the second surface of the heat transfer material support. is provided, the heat conduction portion is configured with a heat conduction potting agent filled in a through hole provided in the heat transfer material support, and the temperature measurement portion is configured to connect the heat conduction potting It is constructed with a temperature measuring element embedded in the agent.

Further, in the fluid sensor according to an aspect of the present invention, a pressure measurement section that measures the pressure of the fluid to be measured that has entered the housing is provided, and the pressure measurement section is configured to connect the pressure sensor element and the fluid to be measured. and an arithmetic circuit that compensates the output of the pressure sensor element according to the temperature of the fluid, and the arithmetic circuit compensates the output according to the temperature of the fluid to be measured measured by the temperature measuring section. It is configured as follows.

Further, the fluid sensor according to an aspect of the present invention is provided with a pressure measurement section that measures the pressure of the fluid to be measured that has entered the housing, and the pressure measurement section includes a pressure sensor element and the pressure sensor. The device is configured to include an arithmetic circuit that compensates the output of the element, and the arithmetic circuit is configured to perform the compensation according to the environmental temperature.

Further, in the fluid sensor according to an aspect of the present invention, the heat transfer material is configured to include a flat plate-like portion having a predetermined thickness, and the first surface of the heat transfer material is arranged such that the first surface of the heat transfer material is The second surface of the heat transfer material is the other surface of the flat plate portion in the thickness direction, and the fluid to be measured entering the housing is The flow direction of the fluid is perpendicular to or nearly perpendicular to the first surface of the heat transfer material, and the fluid to be measured that has entered the housing flows into the first surface of the heat transfer material. It is configured such that the flow direction of the fluid to be measured that has entered the housing changes when it collides with the surface.

According to the present invention, it is possible to provide a fluid sensor that has good responsiveness when measuring the temperature of a fluid to be measured and is easy to manufacture.

1 is a diagram showing the appearance of a fluid sensor according to an embodiment of the present invention. FIG. 1 is a cross-sectional view of a fluid sensor according to an embodiment of the present invention. 3 is an enlarged view of part III in FIG. 2. FIG. FIG. 2 is a perspective view of a heat transfer material and a heat transfer material support of a fluid sensor according to an embodiment of the present invention. FIG. 3 is a diagram showing a sensor according to a comparative example.

The fluid sensor 1 according to the embodiment of the present invention is used, for example, as an oil sensor that measures the temperature of oil, and more specifically, as an on-vehicle oil sensor.

As shown in FIGS. 1 to 4, the automotive oil sensor 1 includes a housing 3, a heat transfer material 5, a heat transfer material support 7, a heat conduction portion 9, and a temperature measurement portion 11. . A fluid to be measured (oil) is placed inside the housing 3 .

Here, for convenience of explanation, one predetermined direction in the vehicle oil sensor 1 is referred to as the X direction, one predetermined direction orthogonal to the X direction is referred to as the Y direction, and the X direction and the Y direction are The orthogonal direction is defined as the Z direction.

The heat transfer material 5 is made of a material with high thermal conductivity such as metal, and is provided integrally with the casing 3 via a heat transfer material support 7 within the casing 3 . The first surface 13 on one side of the heat transfer material 5 is adapted to come into contact with the oil entering the housing 3.

The heat transfer material 5 is configured to transfer heat entering from the first surface 13 toward the second surface 15 on the other side by thermal conduction. Note that the first surface is located on the lower side in the Z direction, and the second surface 15 is located on the upper side in the Z direction, which is the opposite side to the first surface 13. The second surface is not in contact with oil.

The heat transfer material support 7 is made of a material such as a synthetic resin that has a lower thermal conductivity than the heat transfer material 5 and is easier to mold using a mold. The heat transfer material support 7 integrally supports the heat transfer material 5 by engaging with the heat transfer material 5 on the upper side in the Z direction, which is the second surface 15 side of the heat transfer material 5.

For example, the heat transfer material support 7 has a first surface 17 on the lower side in the Z direction that is in contact with a second surface 15 of the heat transfer material to integrally support the heat transfer material 5. There is. Further, the heat transfer material support 7 is installed integrally with the casing 3 within the casing 3.

The heat conductive portion 9 is made of a material of the heat conductive potting agent 25 having higher thermal conductivity than the heat transfer material support 7 , and is provided on the heat transfer material support 7 . The heat transfer portion 9 is a direction from the first surface 17 of the heat transfer material support 7 to the second surface 19 on the other side of the heat transfer material support 7, and is configured to conduct heat transmitted through the heat transfer material 5. is designed to be transferred by heat conduction. The second surface 19 of the heat transfer material support 7 is located on the upper side in the Z direction, which is the opposite side to the first surface 17 of the heat transfer material support 7.

The temperature measurement section 11 includes a temperature measurement element 21 such as a thermistor. The thermistor 21 measures the temperature of the oil that has entered the housing 3 by measuring the temperature of the heat transmitted through the heat conduction portion 9.

The heat transfer material support 7 is provided with a through hole 23 that penetrates from the first surface 17 of the heat transfer material support 7 to the second surface 19 of the heat transfer material support 7 . The heat conductive portion 9 is composed of a heat conductive potting agent (for example, an epoxy potting agent or a silicone potting agent) 25 filled in a through hole 23 provided in the heat transfer material support 7. . Note that the through hole 23 is filled with the heat conductive potting agent 25 so that no voids are present.

The thermistor 21 constituting the temperature measuring section 11 is inserted into the heat conductive potting agent 25. That is, at least a portion of the thermistor 21 is embedded within and in contact with the thermally conductive potting agent 25 .

Note that instead of providing the through holes 23 in the heat transfer material support 7, by providing a recess in a part of the heat transfer material support 7, a part of the heat transfer material support 7 can be formed as a heat transfer material support. 7 may be made thinner. Then, the recessed portion may be filled with a heat conductive potting agent 25, and the thermistor 21 may be inserted into the heat conductive potting agent 25. The thickness dimension of the recessed portion of the heat transfer material support 7 is the dimension in the Z direction, which is the direction from the first surface 17 of the heat transfer material support 7 to the second surface 19 of the heat transfer material support 7. .

Furthermore, the thermistor 21 may be installed in the through hole 23 so that the thermistor 21 directly contacts the heat transfer material 5. Alternatively, the thermistor 21 may be installed in the through hole 23 without providing the heat conductive potting agent 25, so that the thermistor 21 directly contacts the heat transfer material 5.

The heat transfer material support 7 is configured to include a flat plate portion 27 having a predetermined thickness. In this case, the first surface 17 of the heat transfer material support 7 is formed by one surface in the thickness direction of the flat plate portion 27, and the second surface 19 of the heat transfer material support 7 is formed by the flat plate portion 27. It is formed on the other surface in the thickness direction of the shaped portion.

A flat circuit board 29 is provided on the second surface 19 above the flat portion 27 of the heat transfer material support 7 . The thickness direction of the flat plate-shaped portion 27 of the heat transfer material support 7 and the thickness direction of the circuit board 29 are in the Z direction and are coincident with each other.

The thermistor 21 is directly provided on the lower surface in the Z direction, which is one surface in the thickness direction of the circuit board 29 . Thereby, the temperature of the oil can be measured without employing an expensive lead type thermistor 21. Note that, as already understood, one surface of the circuit board 29 in the thickness direction is the lower surface in the Z direction, and is the surface on the flat plate-shaped portion 27 side of the heat transfer material support 7.

Further, the vehicle oil sensor 1 is provided with a pressure measuring section 31 that measures the oil pressure that has entered the housing 3. The pressure measurement section 31 includes a pressure sensor element 33 and an arithmetic circuit 35.

The pressure sensor element 33 has temperature characteristics. That is, the output value of the pressure sensor element 33 fluctuates due to changes in the surrounding temperature. The arithmetic circuit 35 includes, for example, an IC, and is configured to compensate the output (analog output) of the pressure sensor element 33 according to the temperature of the oil measured by the temperature measuring section 11.

The heat transfer material 5 is also configured to include a flat plate-like portion 37 having a predetermined thickness. The first surface 13 of the heat transfer material 5 is one surface of the flat plate-shaped portion 37 in the thickness direction, and is the lower surface in the Z direction. The second surface 15 of the heat transfer material 5 is the other surface of the flat plate portion 37 in the thickness direction, and is the upper surface in the Z direction.

The first surface 13 of the heat transfer material 5, the second surface 15 of the heat transfer material 5, the first surface 17 of the heat transfer material support 7, and the second surface 19 of the heat transfer material support 7 are , perpendicular to the Z direction.

In the on-vehicle oil sensor 1, as shown by arrow A1 in FIG. It is perpendicular to the plane 13 of 1. Note that the direction in which the oil entering the housing 3 flows may be at an angle close to a right angle with respect to the first surface 13 of the heat transfer material 5. That is, the intersection angle between the direction in which the oil entering the housing 3 flows and the first surface 13 of the heat transfer material 5 may be approximately 70° to 110°.

In the automotive oil sensor 1, when the oil that has entered the casing 3 hits the first surface 13 of the heat transfer material 5, the direction in which the oil that has entered the casing 3 flows is reversed, for example. It is configured so that it changes. That is, the direction in which oil flows from the inside of the housing 3 to the outside of the housing 3 is perpendicular to the first surface 13 of the heat transfer material 5 and is from the upper side to the lower side.

Note that the direction in which the oil flows from the inside of the casing 3 to the outside of the casing 3 may be at an angle close to perpendicular to the first surface 13 of the heat transfer material 5. That is, the intersection angle between the direction in which oil flows out of the casing 3 and the first surface 13 of the heat transfer material 5 may be about 70° to 110°.

Here, the vehicle oil sensor 1 will be explained in more detail.

The housing 3 is made of metal, for example, and includes a cylindrical large diameter part 39 and a cylindrical small diameter part 41. The central axis of the large diameter portion 39 and the central axis of the small diameter portion 41 are aligned with each other and extend in the Z direction. The large diameter portion 39 is located above the small diameter portion 41. A pipe thread is formed on the outer periphery of the small diameter portion 41 for attaching the vehicle oil sensor 1 to a cylinder block or the like of a vehicle engine.

Inside the housing 3, a cylindrical first internal space 43, a cylindrical second internal space 45, a cylindrical third internal space 47, and a cylindrical fourth internal space 49 are formed. has been done. The central axis of the first internal space 43, the central axis of the second internal space 45, the central axis of the third internal space 47, and the central axis of the fourth internal space 49 are aligned with each other, and are aligned in the Z direction. It is extending.

The inner diameter of the second inner space 45 is smaller than the inner diameter of the first inner space 43, and the inner diameter of the third inner space 47 is smaller than the inner diameter of the second inner space 45. The inner diameter of the fourth internal space 49 is smaller than the inner diameter of the third internal space 47. The first internal space 43, the second internal space 45, the third internal space 47, and the fourth internal space 49 are arranged in this order from top to bottom in the Z direction.

Further, the first internal space 43 , the second internal space 45 , and the third internal space 47 are located inside the large diameter section 39 , and the fourth internal space 49 is located inside the small diameter section 41 . positioned.

The heat transfer material 5 includes a cylindrical portion 51 and a disk-shaped portion 53. The central axis of the cylindrical portion 51 coincides with the central axis of each internal space 43, 45, 47, and 49. The disk-shaped portion 53 is provided in the cylindrical portion 51 so as to close the opening at the upper end of the cylindrical portion 51 . Note that the disk-shaped portion 53 constitutes the flat plate-shaped portion 37 described above. Further, the cylindrical portion 51 and the disk-shaped portion 53 form a columnar heat transfer material internal space 55 that is open downward in the Z direction.

The heat transfer material support 7 is generally formed into a disk shape. The disk of the heat transfer material support 7 constitutes the above-mentioned flat plate portion 27. The heat transfer material support body 7 is provided integrally with the heat transfer material 5 by insert molding, for example. The heat transfer material support 7 covers the upper portion of the heat transfer material 5 so that at least the heat transfer material internal space 55 and the lower end portion of the cylindrical portion 51 of the heat transfer material 5 are exposed.

The heat transfer material support 7 is provided with a through hole 23 for installing the thermistor 21 and a heat conductive potting agent 25, and a through hole 57 for installing the pressure sensor element 33 and the like. Like the through holes 23, the through holes 57 also penetrate the heat transfer material support 7 in the Z direction.

A thermistor 21 is provided to slightly protrude from the lower surface of the circuit board 29, and when the circuit board 29 is installed on the heat transfer material support 7, the thermistor 21 is located in the through hole 23. ing. Further, the through hole 23 is filled with a thermally conductive potting agent 25, and the thermistor 21 is buried in the thermally conductive potting agent 25. The arithmetic circuit 35 is provided at a predetermined location on the upper surface of the heat transfer material support 7.

The heat transfer material 5 is located generally within the second internal space 45 and the heat transfer material support 7 is located generally within the third internal space 47. The outer periphery of the lower surface of the heat transfer material support 7 is in contact with the stepped portion 59 at the lower end of the second internal space 45 .

Further, the vehicle oil sensor 1 is provided with a terminal portion 61 and an oil flow path forming body 69. The terminal portion 61 includes a metal terminal 63 and a terminal support portion 65 made of, for example, synthetic resin. A lower portion of the terminal portion 61 is located within the first internal space 43.

The outer periphery of the lower end of the terminal support portion 65 is in contact with the outer periphery of the upper end of the heat transfer material support 7, for example, with a biasing force. Further, by caulking the upper end of the housing 3, the terminal portion 61, the heat transfer material support 7, and the heat transfer material 5 are integrated with the housing 3. Note that what is indicated by reference numeral 67 in FIG. 2 etc. is an O-ring having a function as a sealing material.

The oil flow path forming body 69 is obtained by integrally molding, for example, synthetic resin, and includes a cylindrical portion 71, a partition wall 73, and an oil guide wall portion 75. The partition wall 73 is formed into a flat plate shape, and partitions the columnar space inside the cylindrical portion 71 into at least two parts.

Further, the oil guide wall portion 75 protrudes below the cylindrical portion 71. One side of this protruding portion serves as an oil inlet 77, and the other side serves as an oil outlet 79. The partition wall 73 is formed into a disk shape, and is provided at the lower end of the partition wall 73 so that the thickness direction is in the Z direction.

The oil flow path forming body 69 fits into the fourth internal space 49 of the housing 3 . As a result, the oil flow path forming body 69 is provided integrally with the housing 3.

In the vehicle oil sensor 1, the arithmetic circuit 35 compensates the output of the pressure sensor element 33 according to the environmental temperature in addition to or instead of compensating the output of the pressure sensor element 33 according to the oil temperature. It may be configured as follows.

The environmental temperature is the temperature in the environment where the vehicle oil sensor 1 is installed. For example, it is the temperature of the outside air, the cylinder block, etc. when the vehicle-mounted oil sensor 1 is installed and used in the cylinder block of an engine.

To explain further, when the automotive oil sensor 1 is installed and used in the cylinder block of an engine, the pressure sensor element 33 is connected to the pressure sensor element 33 from outside air, the cylinder block, etc. via the terminal (bus bar) 63 and the metal casing 3. The heat is transmitted. Then, the temperature of the pressure sensor element 33 increases and the output value of the pressure sensor element 33 fluctuates. Therefore, the arithmetic circuit 35 compensates the output of the pressure sensor element 33 according to the environmental temperature.

Although the environmental temperature is also measured by the temperature measuring section (first temperature measuring section) 11, a second temperature measuring section (not shown) is separately provided and the environmental temperature is measured by this second temperature measuring section. It may be configured to do so. The second temperature measuring section is provided, for example, at or near the pressure sensor element 33 and is adapted to measure the temperature of the pressure sensor element 33. Note that the second temperature measuring section may measure the temperature of the housing 3, the temperature of the terminal 63, and the temperature of the outside air.

Next, the operation of the vehicle oil sensor 1 will be explained.

As shown in FIG. 3, it is assumed that the on-vehicle oil sensor 1 is installed in the cylinder block of the engine of a vehicle, and oil flows through the oil flow path 81 from left to right in the X direction.

In the state shown in FIG. 3, some of the oil enters from the oil inlet 77 and flows upward in the Z direction, as shown by arrow A1, and the lower end of the cylindrical portion 51 and the flat plate portion 37 of the heat transfer material 5. It collides with the bottom surface. The oil that hits the flat plate-shaped portion 37 flows downward in the Z direction and exits from the oil outlet 79. The oil coming out of the oil outlet 79 flows through the oil flow path 81 from left to right in the X direction.

When the oil that has entered the housing 3 collides with the flat plate-shaped portion 37 of the heat transfer material 5, the heat of the oil is transmitted to the thermistor 21 via the flat plate-shaped portion 37 and the heat-conductive potting agent 25, and the temperature of the oil increases. be measured. Further, the pressure of the oil that has flowed to the flat plate-shaped portion 37 is detected by the pressure measuring section 31.

In the vehicle oil sensor 1, the thermistor 21 measures the temperature of the heat transmitted through the heat conduction part 9 provided on the heat transfer material support 7, and the heat conduction part 9 is made of a material with high thermal conductivity. It is in contact with the heat transfer material 5. This improves responsiveness when measuring oil temperature.

Furthermore, the vehicle oil sensor 1 is configured so that the thermistor 21 measures the temperature of the heat transmitted through the heat conduction portion 9, thereby measuring the temperature of the oil. This eliminates the need to form a long and narrow hole in the metal housing 3, making it easier to manufacture the vehicle oil sensor 1.

The sensor 301 according to the comparative example shown in FIG. 6 is provided with an elongated temperature sensor hole 305 that accommodates the temperature sensor 303 therein. The temperature sensor hole 305 has a temperature sensor hole axis 307 which is inclined towards the sensor axis 309 on the side facing the flowing medium.

Therefore, in the sensor 301 according to the comparative example, it is difficult to process the elongated temperature sensor hole 305, and the work of installing the thermistor into the processed elongated temperature sensor hole 305 becomes troublesome, making the manufacturing process complicated. .

On the other hand, the vehicle-mounted oil sensor 1 does not have an elongated hole for installing the thermistor 21, and there is no need to install the thermistor 21 into the elongated hole, which facilitates manufacturing.

In addition, in the automotive oil sensor 1, the heat transfer material support 7 is provided with a through hole 23, and the heat conductive portion 9 is composed of a heat conductive potting agent 25 filled in the through hole 23, and the thermistor 21 enters the heat conductive potting agent 25. Thereby, heat is efficiently conducted from the oil to the thermistor 21 via the heat transfer material 5 and the heat conductive potting agent 25. The thermistor 21 can then measure the temperature of the oil with good responsiveness.

Furthermore, in the vehicle oil sensor 1, the arithmetic circuit 35 is configured to compensate the output of the pressure sensor element 33 according to the temperature of the oil measured by the temperature measuring section 11. Thereby, the pressure of oil whose temperature changes can be accurately measured using the pressure sensor element 33 having temperature characteristics.

Furthermore, in the automotive oil sensor 1, the direction in which the oil that enters the housing 3 flows is orthogonal to the first surface 13 of the heat transfer material 5, and the oil that enters the housing 3 flows in a direction perpendicular to the first surface 13 of the heat transfer material 5. It is configured to collide with the first surface 13 of the heat transfer material 5. Thereby, the heat of the oil hits the heat transfer material 5 with force, and the heat of the oil is transmitted to the heat transfer material 5 more efficiently.

Although this embodiment has been described above, this embodiment is not limited to these, and various modifications can be made within the scope of the gist of this embodiment.

1 Fluid sensor (vehicle oil sensor)
3 Housing 5 Heat transfer material 7 Heat transfer material support 9 Heat conduction part 11 Temperature measurement section 13 First surface (lower surface of heat transfer material)
15 Second surface (upper surface of heat transfer material)
17 First surface (lower surface of heat transfer material support)
19 Second surface (upper surface of heat transfer material support)
21 Temperature measurement element 23 Through hole (through hole of heat conduction part)
25 Heat conduction potting agent 31 Pressure measurement unit 33 Pressure sensor element 35 Arithmetic circuit 37 Flat plate-shaped portion (flat plate-shaped portion of heat transfer material)

Claims (5)

a housing into which the fluid to be measured enters;
The housing is made of a material with high thermal conductivity, and is provided in the housing so that a first surface on one side is in contact with the fluid to be measured that enters the housing, and the fluid that enters from the first surface is disposed within the housing. a heat transfer material that transfers the generated heat toward a second surface on the other side by thermal conduction;
A heat transfer material made of a material with low thermal conductivity, supporting the heat transfer material by engaging with the heat transfer material on a second surface side of the heat transfer material, and installed in the housing. a support and
The heat transfer material support is made of a material with high thermal conductivity, and is provided on the heat transfer material support, from a first surface on one side of the heat transfer material support to a first surface on the other side of the heat transfer material support. a heat conduction part that transfers heat by thermal conduction in the direction toward the surface of 2;
a temperature measurement unit that measures the temperature of the fluid to be measured by measuring the temperature of the heat transmitted through the heat conduction portion;
has
The heat transfer material support is provided with a through hole penetrating from the first surface of the heat transfer material support to the second surface of the heat transfer material support, and the heat conduction portion is , a fluid sensor filled in the through hole . The thermally conductive portion is composed of a thermally conductive potting agent,
The fluid sensor according to claim 1, wherein the temperature measuring section includes a temperature measuring element embedded in the heat conductive potting agent. A pressure measurement unit is provided to measure the pressure of the fluid to be measured that has entered the housing,
The pressure measurement unit is configured to include a pressure sensor element and an arithmetic circuit that compensates the output of the pressure sensor element according to the temperature of the fluid to be measured,
3. The fluid sensor according to claim 1, wherein the arithmetic circuit is configured to perform the compensation according to the temperature of the fluid to be measured measured by the temperature measuring section. A pressure measurement unit is provided to measure the pressure of the fluid to be measured that has entered the housing,
The pressure measurement unit includes a pressure sensor element and an arithmetic circuit that compensates for the output of the pressure sensor element,
The fluid sensor according to any one of claims 1 to 3 , wherein the arithmetic circuit is configured to perform the compensation according to the outside air temperature at a location where the fluid sensor is installed . The heat transfer material is configured to include a flat plate-shaped portion having a predetermined thickness, and the first surface of the heat transfer material is one surface in the thickness direction of the flat plate-shaped portion, and the first surface of the heat transfer material is one surface in the thickness direction of the flat plate-shaped portion. The second surface of the transmission material is the other surface in the thickness direction of the flat plate portion,
The direction in which the fluid to be measured entering the housing flows is perpendicular to the first surface of the heat transfer material or at an angle close to a right angle,
Claims 1 to 3 are configured such that the flow direction of the fluid to be measured that has entered the housing changes when the fluid to be measured that has entered the housing hits the first surface of the heat transfer material. The fluid sensor according to any one of Item 4.

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