JP5812077B2 - Temperature sensor - Google Patents

Description

  The present invention relates to a temperature sensor that can be easily attached to an object whose temperature is to be detected.

  As a temperature sensor that can be easily attached to an object whose temperature is to be detected, for example, a temperature sensor shown in Patent Document 1 below is known. In this temperature sensor, in order to improve thermal responsiveness, a metal plate excellent in thermal conductivity covers the periphery of the thermal element.

  However, the conventional temperature sensor has a problem that the degree of error (temperature divergence) is large between the actual temperature and the detected temperature, and the time for the temperature sensing element to reach a stable temperature (thermal response) is still slow.

Noto 3007342 publication

  The present invention has been made in view of such a situation, and an object thereof is to be able to be easily attached to an object whose temperature is to be detected, to be able to accurately detect a temperature with a small temperature deviation, and to have a thermal response. It is providing the temperature sensor excellent in property.

In order to achieve the above object, a temperature sensor according to the present invention includes:
A thermal element;
An exterior case in which the thermal element is accommodated;
A temperature sensor having a sealing resin filled around the thermal element inside the exterior case,
The outer case is
A side wall of the case having an opening in a direction in which the lead wire of the thermal element is drawn out;
A case bottom wall formed integrally with the bottom of the case side wall located on the opposite side of the opening;
A projecting portion formed integrally with the side wall of the case and projecting to the opposite side of the opening;
The case bottom wall intersects the case side wall continuous with the projecting portion at an acute angle and is integrated with the projecting portion.

  The temperature sensor according to the present invention can be easily attached to an object (temperature measuring object) whose temperature is to be detected or an attachment part in the vicinity thereof by using the overhanging part. For example, a bolt hole is provided in the overhanging portion, and the temperature sensor can be easily and detachably attached to the temperature measurement object or an attaching portion in the vicinity thereof by a bolt or a screw. Alternatively, the temperature sensor may be easily and detachably attached to the temperature measurement object or its vicinity by inserting the overhanging portion into the insertion groove provided in the temperature measurement object or its vicinity. . Alternatively, the temperature sensor may be attached to the temperature measurement object or an attachment part in the vicinity thereof by bonding the overhang part to the temperature measurement object or an attachment part in the vicinity thereof.

  In addition, the temperature sensor according to the present invention is capable of accurate temperature detection with a small degree of error (temperature divergence) between the actual temperature and the detected temperature, as compared with the conventional temperature sensor, and also excellent in thermal response. Yes. The first reason is considered to be a structure in which one end is closed by the case bottom wall, not the case side wall that opens at both ends in the axial direction. The second reason is considered to be that the case bottom wall intersects the case side wall continuous with the overhanging portion at an acute predetermined angle and is integrated with the overhanging portion.

  When the case bottom wall intersects the case side wall continuous with the overhanging portion at an acute predetermined angle, the heat sensitive element is put inside the outer case and the interior of the outer case is filled with the sealing resin. The tip head is likely to be sandwiched between a bottom wall and a side wall having an acute angle. Therefore, it is expected that the heat transmitted from the temperature measurement object to the overhanging portion or the case side wall continuous to the overhanging portion is transferred to the thermal element without passing through the sealing resin or through the thin sealing resin layer. For this reason, it is considered that the temperature sensor according to the present invention is capable of accurate temperature detection with a small temperature divergence and higher thermal response than the conventional temperature sensor.

  Further, in the present invention, since the tip head of the thermal element is likely to be sandwiched between the bottom wall and the side wall having an acute angle, there is little variation in the position of the thermal element in the exterior case for each product. . For this reason, there is little variation in the characteristics of each temperature sensor product.

Preferably, the projecting portion is formed by pressure-molding one end portion of the cylindrical main body constituting the case side wall into a flat plate shape,
The case bottom wall is automatically formed between the projecting portion press-molded into a flat plate shape and the cylindrical main body that is not press-molded.

  By adopting such a configuration, the manufacturing of the temperature sensor of the present invention becomes very easy, and the temperature difference is small and accurate temperature detection is possible as compared with the conventional temperature sensor, and the thermal responsiveness is further improved. In addition, there is little variation in the characteristics of each temperature sensor product.

FIG. 1 is a perspective view of a temperature sensor according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of the temperature sensor along the line II-II shown in FIG. FIG. 3 is a plan view of the temperature sensor shown in FIG. FIG. 4 is a schematic cross-sectional view of a temperature sensor according to a comparative example (conventional example) of the present invention.

Hereinafter, the present invention will be described based on embodiments shown in the drawings.
As shown in FIGS. 1 and 2, the temperature sensor 2 according to an embodiment of the present invention has a thermal element 4 inside an exterior case 10. The thermosensitive element 4 has an element body 6 and a coating layer 7 that covers the outer periphery of the element body 6.

  The element body 6 is not particularly limited as long as it can detect the temperature. For example, an NTC (Negative Temperature Coefficient) thermistor element, a PTC (Positive Temperature Coefficient) thermistor element, or the like is used. The covering layer 7 is made of an insulating resin or glass. Although it does not specifically limit as resin which comprises the coating layer 7, For example, an epoxy resin, a urethane resin, a silicon resin, ABS resin, PPS resin, PBT resin etc. are used. Moreover, it does not specifically limit as glass which comprises the coating layer 7. FIG.

  A pair of lead wires 8 is connected to the element main body 6, and the temperature signal detected by the element main body 6 can be transmitted to other devices such as a measurement device and a control device through the lead wires 8. The lead wire 8 protrudes in the X-axis direction from the opening 12 formed at one end of the exterior case 10 in the X-axis direction. The lead wire 8 is not particularly limited, and for example, a polyvinyl chloride wire, a polyethylene wire, a silicon wire, a fluorine wire, or the like is used.

  The outer case 10 has an opening 12 in the direction in which the lead wire 8 of the thermal element 4 is drawn out, and has a case side wall 14 surrounding the thermal element 4 (around the X axis). In the present embodiment, the case side wall 14 has a cylindrical shape as shown in FIG. 1, but is not particularly limited, and is a triangular cylinder, a square cylinder, other polygonal cylinders, an elliptical cylinder, or other irregular cylinders. It may be in shape.

  A case bottom wall 20 is formed integrally with the bottom of the case side wall located on the opposite side of the opening 12 in the case side wall 14 in the X-axis direction. Further, a flat plate-like overhanging portion 16 is formed integrally with the side wall 14 and the bottom wall 20 on the opposite side of the case bottom wall 20 in the X-axis direction. The overhanging portion 16 has a plane parallel to the XY axis plane, and has a through hole 18 penetrating in the Z-axis direction at a substantially central portion.

  For example, a bolt or a screw is passed through the through-hole 18 to fix the overhanging portion 16 to the temperature measurement object itself or the attachment projection 40 or the attachment plane 42 shown in FIG. 2 located near the temperature measurement object. Used for.

  Note that the X axis, the Y axis, and the Z axis are perpendicular to each other, the XY axis plane is parallel to the plane of the overhanging portion 16, and the X axis is in the direction in which the lead wire 8 protrudes from the outer case 10. I'm doing it.

  As shown in FIG. 2, in the present embodiment, the case bottom wall 20 extends to the projecting portion 16 on the X axis in a section parallel to the XZ plane perpendicular to the Y axis (a section perpendicular to the plane of the projecting portion 16). The case side wall 14a continuous along the direction intersects at an acute predetermined angle θ and is integrated with the projecting portion 16. The acute predetermined angle θ is not particularly limited as long as it is an acute angle, but it is preferably 45 to 60 degrees. The bottom wall 20 and the overhanging portion 16 can be easily formed by a method as described later.

  As shown in FIG. 3, the width w <b> 1 of the overhang portion 16 in the Y-axis direction is larger than the outer diameter d <b> 1 of the case side wall 14. w1 / d1 is preferably 1-2. The width of the case bottom wall 20 in the Y-axis direction gradually changes from the outer diameter d1 of the case sidewall 14 to the width w1 of the overhanging portion 16 in the Y-axis direction. The outer diameter d1 of the case side wall 14 is larger than the outer diameter of the thermal element 4 accommodated in the exterior case 10, and is preferably 4 to 8 mm.

  The length L1 of the case side wall 14 that is the shortest in the X axis direction around the case side wall 14 is not particularly limited, but is preferably longer than the length of the thermal element 4 in the X axis direction, and preferably 5 to 15 mm. The length L2 of the case bottom wall 20 in the X-axis direction is preferably determined in relation to the outer diameter d1 of the outer case 10. The length (L1 + L2) of the case side wall 14a corresponding to the longest portion in the X-axis direction of the case side wall 14 is determined so that the temperature sensitive element 4 is completely covered with the exterior case 10.

  The length L3 in the X-axis direction of the overhanging portion 16 is determined according to the temperature measurement object or an attachment portion located in the vicinity thereof, and is not particularly limited. Further, in the present embodiment, as shown in FIG. 2, the overhanging portion 16 continues in a straight line with respect to the case side wall 14a corresponding to the longest position in the X-axis direction in the case side wall 14. Then, it is not limited to this, The overhang | projection part 16 may be comprised so that it may be bent at a predetermined angle with respect to the case side wall 14a, and may continue.

  Inside the outer case 10, the temperature sensitive element 4 is accommodated, and further, a sealing resin 30 is filled. Although it does not specifically limit as sealing resin 30, For example, it is comprised with an epoxy resin, a urethane resin, and a silicon resin. In the case where the coating layer 7 is made of a resin, the sealing resin 30 is preferably a resin excellent in adhesion characteristics and heat conduction characteristics as compared with the resin constituting the coating layer 7. The sealing resin 30 may be mixed with a filler or the like. The sealing resin 30 may be filled inside the outer case 10 so as to fill a gap between the temperature sensitive element 4 and the case 10 and protrude slightly from the opening 12. The temperature sensitive element 4 is completely filled with a sealing resin inside the outer case 10.

  The outer case 10 of the temperature sensor 2 according to the present embodiment can be manufactured as follows, for example.

  That is, first, a cylindrical main body having the same outer diameter d1 as the case side wall 14 is prepared. Then, the end of the cylindrical body located at one end in the X-axis direction of the cylindrical main body (the side opposite to the opening 12 shown in FIG. 2) is press-molded into a flat plate shape by a press device, and an overhanging portion is formed. 16 is formed. And the case bottom wall 20 is automatically formed between the projecting portion 16 that is pressure-molded into a flat plate shape and the cylindrical body that is not pressure-molded. It remains as the case side wall 14 as it is. Thereafter, a through hole 18 is formed in the overhang portion 16 as necessary.

  In the temperature sensor 2 according to the present embodiment, the overhanging portion 16 can be used to easily attach to an object (temperature measurement object) whose temperature is to be detected or an attachment portion in the vicinity thereof. For example, a through hole 18 as a bolt hole is provided in the overhanging portion 16, and the temperature sensor 2 is attached to the temperature measurement object itself or the mounting protrusion 40 or the mounting plane 42 in the vicinity thereof by using bolts or screws as shown in FIG. Can be easily attached and detached.

  In addition, the temperature sensor 2 according to the present embodiment is capable of accurate temperature detection with a small degree of error (temperature divergence) between the actual temperature and the detected temperature, as compared with the conventional temperature sensor, and also in terms of thermal responsiveness. Are better. The first reason is that, unlike a temperature sensor having a case side wall 14a in which both axial ends 12, 20a are opened as shown in FIG. 4, for example, in this embodiment, as shown in FIG. This is because one of the X-axis direction end portions of 14 is closed by the case bottom wall 20. As a second reason, as shown in FIG. 2, the case bottom wall 20 intersects the case side wall 14 a continuous with the overhanging portion 16 at an acute predetermined angle θ and is integrated with the overhanging portion 16. It is thought to be for this purpose.

  The case bottom wall 20 intersects the case side wall 14 continuing to the overhanging portion 16 at an acute predetermined angle θ, so that the thermal element 4 is put inside the outer case 10 and the sealing resin 30 is used to seal the outer case 10. When the interior is filled, as shown in FIG. 2, the tip head of the thermal element 4 is likely to be sandwiched between the bottom wall 20 and the side wall 14a having an acute predetermined angle θ. Therefore, the heat transmitted from the temperature measurement object to the overhanging portion 16 or the case side wall 14 continuing to the overhanging portion 16 may be transferred to the thermal element 4 not through the sealing resin 30 or through the thin sealing resin layer. is expected. For this reason, the temperature sensor 2 according to the present embodiment shown in FIGS. 1 to 3 is capable of accurate temperature detection with a small temperature deviation compared to the conventional temperature sensor shown in FIG. Is also excellent.

  More specifically, as compared with the conventional temperature sensor 2a shown in FIG. 4, the temperature sensor 2 of the embodiment shown in FIGS. It was possible to improve at a rate of.

  Compared with the conventional temperature sensor 2a shown in FIG. 4, in the temperature sensor 2 of the embodiment shown in FIGS. 1 to 3, the thermal responsiveness to the temperature measurement object at 85 ° C. is 15% or more. It was possible to improve.

  Further, in the present embodiment, since the tip head of the thermal element 4 is likely to be sandwiched between the bottom wall 20 and the side wall 14a having an acute predetermined angle θ, the position of the thermal element 4 inside the outer case 10 is determined. There is little variation for each product. Therefore, there is little characteristic variation for each product of the temperature sensor 2.

  In addition, in the present embodiment, as described above, the case bottom wall 20 is automatically formed between the projecting portion 16 that is press-molded into a flat plate shape and the cylindrical body that is not press-molded. Therefore, the manufacturing of the temperature sensor 2 (exterior case 10) becomes extremely easy, and the temperature difference is small and accurate temperature detection is possible as compared with the conventional temperature sensor, and the thermal response is also excellent. There is also little variation in the characteristics of the temperature sensor 2 for each product.

  The present invention is not limited to the above-described embodiment, and can be variously modified within the scope of the present invention.

  For example, the through hole 18 is not necessarily formed in the overhanging portion 16. For example, the temperature sensor can be easily and detachably attached to the temperature measurement object or its vicinity by inserting the overhanging portion 16 into the insertion groove provided in the temperature measurement object or the attachment portions 40 and 42 in the vicinity thereof. May be. Alternatively, the temperature sensor 2 may be attached to the temperature measurement object or the attachment parts 40, 42 in the vicinity thereof by bonding the overhang part 16 to the temperature measurement object or the attachment parts 40, 42 in the vicinity thereof.

2 ... Temperature sensor 4 ... Thermal element 6 ... Element body 7 ... Cover layer 8 ... Lead wire 10 ... Exterior case 12 ... Opening 14 ... Case side wall 16 ... Overhang 18 ... Through hole 20 ... Case bottom wall 30 ... Sealing resin 40 ... Mounting projection 42 ... Mounting plane

Claims (1)

A thermal element;
An exterior case in which the thermal element is accommodated;
A temperature sensor having a sealing resin filled around the thermal element inside the exterior case,
The outer case is
A side wall of the case having an opening in a direction in which the lead wire of the thermal element is drawn out;
A case bottom wall formed integrally with the bottom of the case side wall located on the opposite side of the opening;
A projecting portion formed integrally with the side wall of the case and projecting to the opposite side of the opening;
A temperature sensor in which the case bottom wall intersects the case side wall continuous with the overhanging portion at an acute predetermined angle and is integrated with the overhanging portion.

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