Temperature sensor

Abstract

To provide a temperature sensor which is excellent in heat characteristics.SOLUTION: A temperature sensor 1 includes a thermistor element 2, a resin 6, and a case 8. The thermistor element 2 contains a thermistor element assembly 21a. The resin 6 stores at least the thermistor element assembly 21a therein. The case 8 is positioned outside the resin 6 corresponding to the thermistor element assembly 21a, and has an elastic modulus lower than an elastic modulus of the resin 6.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a temperature sensor. [Background technology]

[0002] A known temperature sensor includes a thermistor element including a thermistor body, and a case that houses at least the thermistor body inside (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2019 / 009293 Summary of the Invention [Problem to be solved by the invention]

[0004] The thermal characteristics of a temperature sensor tend to depend on the ease of heat transfer between the thermistor body and the object being measured. An object of one aspect of the present invention is to provide a temperature sensor having excellent thermal characteristics.An object of another aspect of the present invention is to provide a temperature sensor having excellent thermal characteristics. [Means for solving the problem]

[0005] One aspect of the present invention includes a thermistor element, a resin, and a case. The thermistor element includes a thermistor body. The resin contains at least the thermistor body. The case is located outside the resin in correspondence with the thermistor body, and has a modulus of elasticity lower than that of the resin.

[0006] In the one aspect, the case is positioned corresponding to the thermistor element. Therefore, the temperature sensor according to the one aspect can be placed on the measurement object so that the case faces the measurement object. Since the elastic modulus of the case is smaller than that of the resin, the case deforms more easily than the resin. Compared to a configuration in which the case does not face the measurement object, in the one aspect, the case is more likely to deform and conform to the shape of the measurement object, so that the contact area between the temperature sensor and the measurement object is increased. When the contact area between the temperature sensor and the measurement object is increased, heat exchange between the temperature sensor and the measurement object is promoted. Therefore, in the one aspect, heat is easily transferred between the measurement object and the thermistor element. As a result, according to the one aspect, a temperature sensor with excellent thermal characteristics is provided.

[0007] Another aspect of the present invention includes a thermistor element, a resin, and a case. The thermistor element includes a thermistor body. The resin contains at least the thermistor body inside. The case is located outside the resin in correspondence with the thermistor body, and has a thermal conductivity higher than that of the resin.

[0008] In the above-mentioned another aspect, the case is positioned corresponding to the thermistor element. Therefore, the temperature sensor according to the above-mentioned one aspect can be placed on the measurement object so that the case is interposed between the thermistor element and the measurement object. The thermal conductivity of the case is greater than the thermal conductivity of the resin. In the above-mentioned another aspect, heat is more easily transferred between the measurement object and the thermistor element than in a configuration in which the case is not interposed between the thermistor element and the measurement object.

[0009] In the one aspect or the other aspect, the case may have a first case and a second case. The first case may accommodate a resin therein. The second case may be located outside the first case.

[0010] In the one aspect or the another aspect, the second case may have a modulus of elasticity smaller than a modulus of elasticity of the resin and smaller than a modulus of elasticity of the first case. In a configuration in which the elastic modulus of the second case is smaller than that of the first case, the second case deforms more easily than the first case. Compared to a configuration in which the elastic modulus of the second case is larger than that of the first case, the second case located on the outside is more likely to deform and conform to the shape of the object to be measured, so the contact area between the temperature sensor and the object to be measured is further increased. Therefore, in a configuration in which the elastic modulus of the second case is smaller than that of the first case, heat is more easily transmitted between the object to be measured and the thermistor body.

[0011] In the one aspect or the another aspect, the second case may have a thermal conductivity greater than the thermal conductivity of the resin and greater than the thermal conductivity of the first case. In a configuration in which the thermal conductivity of the second case is greater than that of the first case, the second case located on the outside conducts heat more easily than the first case. Compared to a configuration in which the thermal conductivity of the second case is smaller than that of the first case, heat exchange between the second case located on the outside and the object to be measured is further promoted. Therefore, in a configuration in which the thermal conductivity of the second case is greater than that of the first case, heat conducts more easily between the object to be measured and the thermistor element.

[0012] In the one aspect or the another aspect, the second case may be arranged along the outer periphery of the first case so as to surround the thermistor body outside the first case. In a configuration in which the second case fits around the outer periphery of the first case so as to surround the thermistor body outside the first case, the thermistor body is surrounded by the second case, to which heat is easily transferred from the object to be measured, making it even easier for heat to be transferred between the object to be measured and the thermistor body.

[0013] In the one aspect or the other aspect, the thermistor element may include a conductor electrically connected to the thermistor body and located within the first case. The first case may include a first portion and a second portion. The first portion may be located corresponding to the thermistor body, and the second portion may be continuous with the first portion and located corresponding to the conductor. The first portion and the second portion may form a step in which the first portion is lower than the second portion. In a configuration in which the first portion and the second portion form a step in which the first portion is lower than the second portion, the distance between the object to be measured and the thermistor body is more likely to be reduced compared to a configuration in which there is no step, and heat is therefore more easily transferred between the object to be measured and the thermistor body.

[0014] In the one aspect or the other aspect, the second case may be attached to the first portion. In a configuration in which the second case is attached to the first part, the second case, through which heat is easily transmitted, is located in the first part where the distance between the object to be measured and the thermistor body is likely to decrease, so that heat is even more easily transmitted between the object to be measured and the thermistor body.

[0015] In the one aspect or the other aspect, the first case may further include a third portion continuous with the first portion such that the first portion is located between the second portion and the third portion. The first portion and the third portion may form a step in which the first portion is lower than the third portion. In a configuration in which the first portion and the third portion form a step in which the first portion is lower than the third portion, the second case is attached to the first portion which is lower than both the second portion and the third portion, so that the second case is unlikely to fall off the first case.

[0016] In the one aspect or the another aspect, the first portion, the second portion, and the third portion may form a groove along the entire circumference of the first case. In a configuration in which the first part, the second part, and the third part form a groove along the entire circumference of the first case, the second case is attached to the groove, making the second case even less likely to fall off the first case.

[0017] In the one aspect or the other aspect, the thermistor element may include a conductor wire electrically connected to the thermistor body and located within the first case. The first case may include a first portion and a second portion. The first portion may be located corresponding to the thermistor body. The second portion may be continuous with the first portion, be located corresponding to the conductor wire, and have a thickness different from a thickness of the first portion. In a configuration in which the first case includes the first and second parts, the second part located corresponding to the conductor has less effect on the thermal characteristics than the first part, and the first part located corresponding to the thermistor body has more effect on the thermal characteristics than the second part. Since the thickness of the first part and the thickness of the second part are different from each other, in this configuration, the thickness of each of the first part and the second part can be selected depending on the effect on the thermal characteristics.

[0018] In the one aspect or the other aspect, the second case may include a portion located on the first portion and in contact with the object to be measured. In a first cross section including the thermistor body, the first case, and portions of the second case, a thickness of the first portion may be smaller than a thickness of the second portion. In a second cross section perpendicular to the first cross section, a thickness of the first portion may be larger than a thickness of the second portion. In a configuration in which the thickness of the first portion is smaller than the thickness of the second portion in a first cross section including the thermistor body, the first case, and the above-mentioned portions of the second case, the small thickness of the first portion tends to reduce the distance between the measurement object and the thermistor body in the direction along the first cross section, resulting in easy transfer of heat between the measurement object and the thermistor body. A configuration in which the thickness of the first portion is greater than the thickness of the second portion in a second cross section perpendicular to the first cross section makes it easier to improve the strength of the first case in the direction along the second cross section, since the thickness of the first portion is greater.

[0019] In the one aspect or the another aspect, in the first cross section, a thickness of the portion of the second case may be greater than a thickness of the first portion. In a configuration in which the thickness of the second case portion in the first cross section is greater than the thickness of the first portion, the thickness of the second case between the object to be measured and the thermistor body is greater than the thickness of the first portion, so that heat is more easily transferred between the object to be measured and the thermistor body.

[0020] In the one aspect or the other aspect, at the second cross section, a thickness of the first portion may be greater than a thickness of the second case portion. A configuration in which the thickness of the first portion in the second cross section is greater than the thickness of the portion of the second case tends to improve the strength of the first case in the direction along the second cross section. Effect of the Invention

[0021] An aspect of the present invention provides a temperature sensor having excellent thermal characteristics. Another aspect of the present invention provides a temperature sensor having excellent thermal characteristics. [Brief description of the drawings]

[0022] [Figure 1] FIG. 1 is a perspective view of a temperature sensor according to an embodiment. [Diagram 2] FIG. 2 is a diagram showing a cross-sectional configuration of the temperature sensor according to this embodiment. [Diagram 3] FIG. 3 is a diagram showing a cross-sectional configuration of the temperature sensor according to this embodiment. [Figure 4] FIG. 4 is a diagram showing a cross-sectional configuration of the temperature sensor according to this embodiment. [Diagram 5] FIG. 5 is a diagram showing a cross-sectional configuration of a temperature sensor according to a modified example of this embodiment. [Figure 6] FIG. 6 is a diagram showing a cross-sectional configuration of a temperature sensor according to another modified example of this embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the description of the drawings, the same or corresponding elements are given the same reference numerals, and duplicated description will be omitted as appropriate.

[0024] The configuration of the temperature sensor according to the present embodiment will be described with reference to Figures 1 to 4. Figure 1 is a perspective view of the temperature sensor according to the present embodiment. Figures 2 to 4 are diagrams showing the cross-sectional configuration of the temperature sensor according to the present embodiment.

[0025] 1 to 3, the temperature sensor 1 includes a thermistor element 2, an insulating member 3, a wire 4, a resin 6, and a case 8. The case 8 has a case 5 and a case 7. For example, the case 5 is defined as a first case, and the case 7 is defined as a second case. As shown in Fig. 4, the temperature sensor 1 measures the temperature of a measurement object 100 facing its surface.

[0026] 2 and 3, the thermistor element 2 has a thermistor body portion 21 and a conductor 22. The thermistor element 2 is an electronic component whose resistance value changes in response to an increase in temperature. The thermistor body portion 21 includes a thermistor body 21a and a sealing body 21b. The thermistor body 21a may include an NTC (Negative Temperature Coefficient) thermistor and a PTC (Positive Temperature Coefficient) thermistor. The thermistor body 21a constitutes a detection portion whose resistance value changes in response to a change in temperature.

[0027] The sealing body 21b seals the thermistor element body 21a inside. The thermistor element body 21a is covered with the sealing body 21b. In one example, the sealing body 21b is made of glass. In one example, the conductor 22 is a dumet wire. The conductor 22 includes a conductor 22a and a conductor 22b. The conductor 22a and the conductor 22b are electrically connected to two electrodes provided on the thermistor element body 21a, respectively. For example, the conductor 22a and the conductor 22b are connected to the two electrodes by solder, respectively. Each of the conductors 22a, 22b includes a portion sealed in the sealing body 21b together with the thermistor element body 21a and a portion exposed from the sealing body 21b.

[0028] The insulating member 3 is disposed adjacent to the thermistor body 21 and along at least a portion of the conductor 22. A pair of grooves 31, 32 are formed in the insulating member 3. The pair of grooves 31, 32 are adjacent to each other on the same plane. The pair of grooves 31, 32 are separated so as not to cross each other. A part of the insulating member 3 is interposed between the conductor 22a and the conductor 22b. In the insulating member 3, each of the grooves 31, 32 penetrates both ends in the direction in which each of the grooves 31, 32 extends. The width and depth of each of the grooves 31, 32 are larger than the diameter of each of the conductors 22a, 22b. The conductors 22a and 22b are disposed in the grooves 31 and 32, respectively. The conductors 22a and 22b may be fixed in the grooves 31 and 32, respectively, by an adhesive.

[0029] The wire 4 is electrically connected to the conductor 22. In one example, the wire 4 is connected to the conductor 22 by a crimping member (not shown). The wire 4 is, for example, a coated electric wire. The wire 4 has a wire 41 and a wire 42. The wire 41 and the wire 42 are electrically connected to the conductor 22a and the conductor 22b, respectively. Between the insulating member 3 and the wire 4, the conductor 22 includes a curved portion 2a in which the conductor 22a and the conductor 22b are curved away from each other. In the curved portion 2a, the conductor 22a and the conductor 22b are curved such that the distance between the conductor 22a and the conductor 22b corresponds to the distance between the wire 41 and the wire 42.

[0030] The resin 6 accommodates at least the thermistor body 21a therein. In this embodiment, the resin 6 accommodates the thermistor element 2, the insulating member 3, and a portion of the wire 4 therein. The resin 6 may be formed by filling the inside of the case 5. For example, the resin 6 is made of an epoxy resin, a silicone resin, or a polyurethane resin. In one example, the elastic modulus of the resin 6 is 2 GPa or more and 20 GPa or less. In one example, the thermal conductivity of the resin 6 is 0.1 W / m·K or more and 30 W / m·K or less. The resin 6 fixes the thermistor element 2, the insulating member 3, and a portion of the wire 4 inside the case 5, and seals the thermistor element 2 and the insulating member 3 inside the case 5.

[0031] The case 5 contains the resin 6 therein. In this embodiment, the case 5 contains the thermistor element 2, the insulating member 3, and a part of the wire 4 together with the resin 6. The case 5 has a bottomed cylindrical shape. The case 5 includes an end face 5a in which an opening 50 is formed and a bottom face 5b opposite the end face 5a. The thermistor element 2 is contained in the case 5 such that the thermistor body portion 21 and the bottom face 5b are adjacent to each other. The wire 4 is contained in the case 5 such that a part of the wire 4 is contained in the case 5 and another part of the wire 4 that is continuous with the part is exposed from the opening 50. In this embodiment, the case 5, the thermistor element 2, and the wire 4 are positioned such that the direction D1 in which the end face 5a and the bottom face 5b face each other and the direction in which the thermistor element 2 and the wire 4 are adjacent to each other are aligned with each other.

[0032] For example, the case 5 is made of resin. The case 5 may be made of PPS (polyphenylene sulfide) resin, PA (polyamide) resin, or PBA (polybutylene terephthalate) resin. In one example, the elastic modulus of the case 5 is 8 GPa or more and 20 GPa or less. In one example, the thermal conductivity of the case 5 is 0.2 W / m·K or more and 30 W / m·K or less.

[0033] As shown in FIG. 1, the case 5 has, for example, a rectangular parallelepiped shape. The rectangular parallelepiped includes a rectangular parallelepiped with chamfered corners and ridges, a rectangular parallelepiped with rounded corners and ridges, and a rectangular parallelepiped with each face having a step. The case 5 includes an end face 5a, a bottom face 5b, a side face 5c, a side face 5d, a side face 5e, and a side face 5f. The side faces 5c, 5d, 5e, and 5f are adjacent to the end face 5a and the bottom face 5b, respectively, and connect the end face 5a and the bottom face 5b, respectively. The end face 5a, the bottom face 5b, the side face 5c, the side face 5d, the side face 5e, and the side face 5f constitute the surface of the case 5. The side face 5c and the side face 5d face each other in the direction D3. The side face 5e and the side face 5f face each other in the direction D2. The length of the side faces 5c and 5d along the direction D2 is greater than the length of the side faces 5e and 5f along the direction D3.

[0034] The direction D1 is perpendicular to the end surface 5a and the bottom surface 5b. The direction D2 is perpendicular to the side surfaces 5e and 5f. The direction D2 is perpendicular to the direction D1. The direction D3 is perpendicular to the side surfaces 5c and 5d. The direction D3 is perpendicular to the direction D1. The directions D2 and D3 are perpendicular to each other.

[0035] The case 7 is located outside the resin 6 in correspondence with the thermistor element 21a. In this embodiment, the case 5 is interposed between the resin 6 and the case 7. The case 7 is located outside the case 5. The case 7 may be in direct contact with the case 5. Another member may be interposed between the case 5 and the case 7. The another member may facilitate heat transfer between the case 5 and the case 7. As shown in FIG. 1, the case 7 is located along the outer periphery of the case 5 so as to surround the thermistor element 21a outside the case 5. In the directions D2 and D3, the case 7 and thermistor element 21 are adjacent to each other with the resin 6 and the case 5 sandwiched therebetween.

[0036] In this embodiment, case 7 has a cylindrical shape. Case 7 is positioned such that the central axis of case 7 is along direction D1. Case 7 fits along the entire outer periphery of case 5. Case 7 includes portions 7c, 7d, 7e, and 7f. Portions 7c and 7d face each other in direction D3, sandwiching case 5 therebetween. Portions 7e and 7f face each other in direction D2, sandwiching case 5 therebetween.

[0037] Case 7 has a modulus of elasticity smaller than that of resin 6 and smaller than that of case 5. Case 7 has a thermal conductivity larger than that of resin 6 and may have a thermal conductivity larger than that of case 5.

[0038] In this embodiment, case 7 has a modulus of elasticity smaller than that of case 5 and has a thermal conductivity larger than that of case 5. In a configuration in which case 7 has a modulus of elasticity smaller than that of case 5 and has a thermal conductivity larger than that of case 5, case 7 is made of, for example, silicone resin or carbon nanotubes.

[0039] Case 7 may have at least one of an elastic modulus smaller than that of case 5 and a thermal conductivity larger than that of case 5. In one example, case 7 has an elastic modulus of 9 MPa or more and 18 GPa or less. In one example, case 7 has a thermal conductivity of 0.8 W / m K or more and 400 W / m K or less. In one example, case 7 may have a modulus of elasticity smaller than that of case 5 and a thermal conductivity equal to or smaller than that of case 5. In a configuration in which case 7 has a modulus of elasticity smaller than that of case 5, case 7 is made of fluororubber, polyurethane resin, or nylon resin. In one example, case 7 may have an elastic modulus equal to or greater than that of case 5, and a thermal conductivity greater than that of case 5. In a configuration in which case 7 has a thermal conductivity greater than that of case 5, case 7 is made of aluminum, stainless steel, or copper.

[0040] As shown in Figs. 2 and 3, in this embodiment, the case 5 includes a portion 51, a portion 52, and a portion 53. The portion 51 is located corresponding to the thermistor element body 21a. In the directions D2 and D3, the thermistor element body 21 and the portion 51 are adjacent to each other with the resin 6 sandwiched therebetween. The portion 52 is continuous with the portion 51 and is located corresponding to the conductive wire 22. The portion 51 is cylindrical. The portion 52 may be located corresponding to a part of the insulating member 3 and the wire 4. In the directions D2 and D3, the conductive wire 22 and the portion 52 are adjacent to each other with the resin 6 sandwiched therebetween. The portion 52 is cylindrical including the end face 5a and the opening 50.

[0041] Part 53 is continuous with part 51 such that part 51 is located between part 52. Part 53 has a bottomed cylindrical shape including a bottom surface 5b. Parts 51, 52, and 53 are continuous with each other in the direction D1 in the order of part 53, part 51, and part 52. For example, part 51 is defined as a first part, part 52 is defined as a second part, and part 53 is defined as a third part.

[0042] The portion 51 and the portion 52 form a step 54 in which the portion 51 is lower than the portion 52. In one example, the step 54 includes a step 54c, a step 54d, a step 54e, and a step 54f. The step 54c is included in the side surface 5c. The step 54d is included in the side surface 5d. The step 54e is included in the side surface 5e. The step 54f is included in the side surface 5f. The steps 54c, 54d, 54e, and 54f are continuous.

[0043] Portion 51 and portion 53 form a step 55 in which portion 51 is lower than portion 53. In one example, step 55 includes steps 55c, 55d, 55e, and 55f. Step 55c is included in side surface 5c. Step 55d is included in side surface 5d. Step 55e is included in side surface 5e. Step 55f is included in side surface 5f. Steps 55c, 55d, 55e, and 55f are continuous.

[0044] The portions 51, 52, and 53 form a groove 56 along the entire circumference of the case 5. The bottom surface of the groove 56 is included in the portion 51. A pair of inner walls of the groove 56 are included in the steps 54 and 55, respectively. The case 7 is attached to the portion 51. The case 7 is disposed on the portion 51. In this embodiment, the case 7 is attached in the groove 56. The case 7 is located on the portion 51 and between the steps 54 and 55.

[0045] Portion 52 has a thickness different from the thickness of portion 51. The "thickness" of a portion of case 5 is the length between a surface of case 5 and an inner surface of case 5 in a direction perpendicular to direction D1. As shown in Figure 2, portion 52 has a thickness a2 different from a thickness a1 of portion 51 in direction D3. As shown in Figure 3, portion 52 has a thickness b2 different from a thickness b1 of portion 51 in direction D2.

[0046] The case 7 includes at least one portion that is located on the portion 51 and that contacts the measurement object. As shown in FIG. 4, in this embodiment, the case 7 includes a portion 7c and a portion 7d that are located on the portion 51 and that contact the measurement object 100. For example, the cross section of the temperature sensor 1 shown in FIG. 2 is defined as a first cross section that includes the thermistor body 21a, the case 5, and the portions 7c and 7d of the case 7. The thickness in the cross section of FIG. 2 is the thickness in the direction D3. For example, the cross section of the temperature sensor 1 shown in FIG. 3 is defined as a second cross section that is perpendicular to the cross section of FIG. 2. The cross section of the temperature sensor 1 shown in FIG. 3 is a cross section that includes the thermistor body 21a, the case 5, and the portions 7e and 7f of the case 7. The thickness in the cross section of FIG. 3 is the thickness in the direction D2.

[0047] As shown in FIG. 2, the thickness a1 of the portion 51 is smaller than the thickness a2 of the portion 52. In one example, the thickness a1 is 0.1 mm or more and 0.5 mm or less, and the thickness a2 is 0.2 mm or more and 1.0 mm or less. The thickness a3 of each of the portions 7c and 7d is greater than the thickness a1 of the portion 51. As shown in FIG. 3, the thickness b1 of the portion 51 is greater than the thickness b2 of the portion 52. In one example, the thicknesses a3 and b3 are 0.2 mm or more and 0.8 mm or less. The thickness b3 of each of the portions 7e and 7f is smaller than the thickness b1 of the portion 51. The thickness a1 is smaller than the thickness b1 and the thickness b2.

[0048] As described above, the case 7 is located in correspondence with the thermistor body 21a. Therefore, the temperature sensor 1 can be placed on the measurement object 100 so that the case 7 faces the measurement object 100. Since the elastic modulus of the case 7 is smaller than that of the case 5, the case 7 deforms more easily than the case 5. Compared to a configuration in which the case 7 does not face the measurement object 100, in the temperature sensor 1, as shown in FIG. 4, the case 7 is more likely to deform and conform to the shape of the measurement object 100, so that the contact area between the temperature sensor 1 and the measurement object 100 is increased. When the contact area between the temperature sensor 1 and the measurement object 100 is increased, the heat exchange between the temperature sensor 1 and the measurement object 100 is promoted. Therefore, in the temperature sensor 1, heat is easily transferred between the measurement object 100 and the thermistor body 21a. As a result, the temperature sensor 1 has excellent thermal characteristics. The case 7 is located corresponding to the thermistor element 21a. Therefore, the temperature sensor 1 can be placed on the measurement object 100 such that the case 7 is interposed between the thermistor element 21a and the measurement object 100. The thermal conductivity of the case 7 is greater than the thermal conductivity of the case 5. Compared to a configuration in which the case 7 is not interposed between the thermistor element 21a and the measurement object 100, in the temperature sensor 1, heat is more easily transferred between the measurement object 100 and thermistor element 21a. As a result, the temperature sensor 1 has excellent thermal characteristics.

[0049] In the temperature sensor 1, the case 7 is disposed along the outer periphery of the case 5 so as to surround the thermistor body 21a outside the case 5. In the temperature sensor 1, the thermistor body 21a is surrounded by the case 7 to which heat is easily transferred from the measurement object 100, so that heat is transferred even more easily between the measurement object 100 and thermistor body 21a.

[0050] In the temperature sensor 1, the thermistor element 2 includes a conductor 22 that is electrically connected to the thermistor element body 21a and is located within a case 5. The case 5 includes a portion 51 and a portion 52. The portion 51 is located corresponding to the thermistor element body 21a. The portion 52 is continuous with the portion 51 and is located corresponding to the conductor 22. The portions 51 and 52 form a step 54 in which the portion 51 is lower than the portion 52. In the temperature sensor 1, the distance between the measurement object 100 and thermistor body 21a is more easily reduced than in a configuration without the step 54, so heat is more easily transferred between the measurement object 100 and thermistor body 21a.

[0051] In the temperature sensor 1 , the case 7 is attached to the portion 51 . In the temperature sensor 1, the case 7, through which heat is easily transmitted, is located in the portion 51 where the distance between the object to be measured 100 and thermistor body 21a is likely to decrease, so that heat is even more easily transmitted between the object to be measured 100 and thermistor body 21a.

[0052] In the temperature sensor 1, the case 5 further includes a portion 53 that is continuous with the portion 51 such that the portion 51 is located between the portion 52. The portions 51 and 53 form a step 55 in which the portion 51 is lower than the portion 53. In the temperature sensor 1, the case 7 is attached to the portion 51 which is lower than both the portion 52 and the portion 53, so that the case 7 is unlikely to fall off the case 5.

[0053] In the temperature sensor 1 , the portion 51 , the portion 52 , and the portion 53 form a groove 56 along the entire circumference of the case 5 . In the temperature sensor 1, since the case 7 is attached to the groove 56, the case 7 is even less likely to fall off the case 5.

[0054] In the temperature sensor 1, the thermistor element 2 includes a conductor 22 that is electrically connected to the thermistor body 21a and is located within the case 5. The case 5 includes a portion 51 and a portion 52. The portion 51 is located corresponding to the thermistor body 21a. The portion 52 is continuous with the portion 51, is located corresponding to the conductor 22, and has a thickness different from the thickness of the portion 51. In the temperature sensor 1, the portion 52 located corresponding to the conductive wire 22 is less likely to affect the thermal characteristics than the portion 51, and the portion 51 located corresponding to the thermistor element body 21a is more likely to affect the thermal characteristics than the portion 52. Since the thickness of the portion 51 and the thickness of the portion 52 are different from each other, in the temperature sensor 1, the thickness of each of the portions 51 and 52 can be selected depending on the effect on the thermal characteristics.

[0055] In the temperature sensor 1, the case 7 includes portions 7c and 7d which are located on portion 51 and which contact the measurement object 100. In a first cross section which includes the thermistor body 21a, the case 5, and portions of the case 7, the thickness a1 of the portion 51 is smaller than the thickness a2 of the portion 52. In a second cross section which is perpendicular to the first cross section, the thickness b1 of the portion 51 is larger than the thickness b2 of the portion 52. In the temperature sensor 1, since the thickness a1 is smaller than the thickness a2, the distance between the measurement object 100 and thermistor body 21a tends to decrease in the direction D3. As a result, heat is easily transferred between the measurement object 100 and thermistor body 21a. In the temperature sensor 1, since the thickness b1 is greater than the thickness b2, it is easy to improve the strength of the case 5 in the direction D3. In the temperature sensor 1, the case 5 is made of resin. Compared to a configuration in which the portion 51 has only a smaller thickness than the portion 52, the thickness b1 of the portion 51 is larger than the thickness b2, so that the flow of the resin when forming the portion 51 is good.

[0056] In the temperature sensor 1, the thickness of the portion of the case 7 is greater than the thickness of the portion 51 in the second cross section. In the temperature sensor 1, the thickness of the case 7 between the measurement object 100 and thermistor body 21a is greater than the thickness of the portion 51, so that heat is transferred more easily between the measurement object 100 and thermistor body 21a.

[0057] In the temperature sensor 1, the thickness of the portion 51 is greater than the thickness of the portion of the case 7 in cross section. In the temperature sensor 1, the strength of the case 5 in the direction along the cross section can be easily improved.

[0058] In the temperature sensor 1, at least a part of the insulating member 3 is interposed between the conductor 22a and the conductor 22b. Therefore, a short circuit is unlikely to occur between the conductor 22a and the conductor 22b. In the temperature sensor 1, the insulating member 3 is disposed between the thermistor body 21 and the curved portion 2a, so that the bending stress of the conductor 22 at the curved portion 2a is unlikely to be transmitted to the portion where the conductor 22 is pulled out from the sealing body 21b. Therefore, in the temperature sensor 1, breakage of the conductor 22 is unlikely to occur.

[0059] Next, an embodiment according to a modified example of the temperature sensor 1 will be described with reference to Fig. 5. Fig. 5 is a diagram showing a cross-sectional configuration of a temperature sensor according to a modified example of this embodiment. The temperature sensor 1A according to the modified example differs from the temperature sensor 1 in terms of the configuration of the case 8. The following mainly describes the differences between the temperature sensor 1 and the temperature sensor 1A.

[0060] The temperature sensor 1A includes a case 8A. The case 8A includes a case 5A and a case 7A. For example, the case 5A is defined as a first case, and the case 7A is defined as a second case. The case 5A does not include a plurality of portions forming steps. Each of the side surfaces 5c, 5d, 5e, and 5f constituting the case 5A is a flat surface. The case 7A is located outside the case 5, corresponding to the thermistor element 2, the insulating member 3, and the wire 4 inside the case 5. The case 7A covers the entire surfaces of each of the side surfaces 5c, 5d, 5e, and 5f and the bottom surface 5b. The thickness of the case 7A is approximately equal.

[0061] Next, an embodiment according to a modified example of the temperature sensor 1 will be described with reference to FIG. 6. FIG. 6 is a diagram showing a cross-sectional configuration of a temperature sensor according to another modified example of this embodiment. The case does not have to have a first case and a second case. Temperature sensor 1B according to the modified example differs from temperature sensor 1A in the configuration of case 8A. Below, the differences between temperature sensor 1A and temperature sensor 1B will be mainly described.

[0062] The temperature sensor 1B includes a case 8B that does not have another case inside. The case 8B may have the same shape as the case 7A. The case 8B does not have a case 5A inside. For example, the case 8B has a bottomed cylindrical shape. The case 8B is located outside the resin 6 in correspondence with the thermistor body 21a. The case 8B directly accommodates the resin 6 inside. The resin 6 may be formed by filling the inside of the case 8B. In this embodiment, the case 8B has a modulus of elasticity smaller than that of the resin 6 and a thermal conductivity larger than that of the resin 6. The case 8B is made of, for example, a silicone resin or carbon nanotubes.

[0063] The present invention has been described in detail above based on the embodiments. However, the present invention is not limited to the above embodiments. The present invention can be modified in various ways without departing from the gist of the present invention.

[0064] Each of the steps 54, 54 is not limited to a step perpendicular to the direction D1. Each of the steps 54, 54 may intersect with the direction D1. Each of the steps 54, 54 may include a tapered shape. The portions 51, 52, and 53 do not necessarily have to form the groove 56 along the entire circumference of the case 5. The portions 51, 52, and 53 may form a groove along at least a part of the side surfaces 5c, 5d, 5e, and 5f. Case 7 does not have to follow the outer periphery of case 5 so as to surround thermistor body 21a outside case 5. Case 7 only needs to be located on at least a portion of the outside of case 5 corresponding to thermistor body 21a. The case 7A does not have to cover the bottom surface 5b, and may cover only the side surfaces 5c, 5d, 5e, and 5f. The shape of the case 5 is not limited to a rectangular parallelepiped. The shape of the case 5 is not limited to a cylindrical shape with a bottom. It is sufficient that the case 5 accommodates at least the thermistor body 21a therein. It is sufficient that case 8B has at least one of a modulus of elasticity smaller than that of resin 6 and a thermal conductivity larger than that of resin 6.

[0065] As will be understood from the above description of the embodiments and modifications, this specification includes disclosure of the following aspects. (Appendix 1) a thermistor element including a thermistor body; a resin housing at least the thermistor body therein; a case located outside the resin in correspondence with the thermistor body and having an elastic modulus smaller than that of the resin, said temperature sensor comprising: (Appendix 2) a thermistor element including a thermistor body; a resin housing at least the thermistor body therein; a case located outside the resin in correspondence with the thermistor body and having a thermal conductivity greater than that of the resin, said temperature sensor comprising: (Appendix 3) The case is a first case containing the resin therein; and a second case located outside the first case. 3. The temperature sensor according to claim 1 or 2. (Appendix 4) The elastic modulus of the second case is smaller than the elastic modulus of the resin and is also smaller than the elastic modulus of the first case. 4. The temperature sensor according to claim 3. (Appendix 5) The thermal conductivity of the second case is greater than the thermal conductivity of the resin and is greater than the thermal conductivity of the first case. 4. The temperature sensor according to claim 3. (Appendix 6) the second case is arranged along the outer periphery of the first case so as to surround the thermistor body outside the first case; The temperature sensor according to any one of claims 3 to 5. (Appendix 7) the thermistor element includes a conductor electrically connected to the thermistor body and located within the first case; The first case is a first portion located corresponding to the thermistor body; a second portion contiguous with the first portion and positioned corresponding to the conductor; The first portion and the second portion form a step in which the first portion is lower than the second portion. The temperature sensor according to any one of claims 3 to 5. (Appendix 8) The second case is attached to the first part. 8. The temperature sensor of claim 7. (Appendix 9) the first case further includes a third portion contiguous with the first portion such that the first portion is located between the second portion and the third portion; The first portion and the third portion form a step in which the first portion is lower than the third portion. 9. The temperature sensor according to claim 7 or 8. (Appendix 10) the first portion, the second portion, and the third portion form a groove along the entire circumference of the first case; 10. The temperature sensor of claim 9. (Appendix 11) the thermistor element includes a conductor electrically connected to the thermistor body and located within the first case; The first case is a first portion located corresponding to the thermistor body; a second portion continuous with the first portion, positioned corresponding to the conductive wire, and having a thickness different from a thickness of the first portion; The temperature sensor according to any one of claims 3 to 5. (Appendix 12) the second case includes a portion located on the first portion and in contact with the measurement object, in a first cross section including the thermistor body, the first case, and the portion of the second case, the thickness of the first portion is smaller than the thickness of the second portion; In a second cross section perpendicular to the first cross section, the thickness of the first portion is greater than the thickness of the second portion. 12. The temperature sensor of claim 11. (Appendix 13) At the first cross section, the thickness of the portion of the second case is greater than the thickness of the first portion. 13. The temperature sensor of claim 12. (Appendix 14) At the second cross section, the thickness of the first portion is greater than the thickness of the portion of the second case. 14. The temperature sensor according to claim 12 or 13. [Explanation of symbols]

[0066] 1, 1A, 1B...temperature sensor, 2...thermistor element, 21...thermistor body portion, 21a...thermistor body, 22...conductor, 5, 5A...case, 7, 7A...case, 8, 8A, 8B...case, 51, 52, 53...part, 56...groove, 54, 55...step, 100...object to be measured.

Claims

1. a thermistor element including a thermistor body; a resin housing at least the thermistor body therein; a case located outside the resin in correspondence with the thermistor body and having an elastic modulus smaller than that of the resin, said temperature sensor comprising:

2. a thermistor element including a thermistor body; a resin housing at least the thermistor body therein; a case located outside the resin in correspondence with the thermistor body and having a thermal conductivity greater than that of the resin, said temperature sensor comprising:

3. The case is a first case containing the resin therein; and a second case located outside the first case.

3. The temperature sensor according to claim 1 or 2.

4. The elastic modulus of the second case is smaller than the elastic modulus of the resin and is also smaller than the elastic modulus of the first case. The temperature sensor according to claim 3.

5. The thermal conductivity of the second case is greater than the thermal conductivity of the resin and is greater than the thermal conductivity of the first case. The temperature sensor according to claim 3.

6. the second case is arranged along the outer periphery of the first case so as to surround the thermistor body outside the first case; The temperature sensor according to claim 3.

7. the thermistor element includes a conductor electrically connected to the thermistor body and located within the first case; The first case is a first portion located corresponding to the thermistor body; a second portion contiguous with the first portion and positioned corresponding to the conductor; The first portion and the second portion form a step in which the first portion is lower than the second portion. The temperature sensor according to claim 3.

8. The second case is attached to the first part. The temperature sensor according to claim 7.

9. the first case further includes a third portion contiguous with the first portion such that the first portion is located between the second portion and the third portion; The first portion and the third portion form a step in which the first portion is lower than the third portion. The temperature sensor according to claim 8.

10. the first portion, the second portion, and the third portion form a groove along the entire circumference of the first case; The temperature sensor according to claim 9.

11. the thermistor element includes a conductor electrically connected to the thermistor body and located within the first case; The first case is a first portion located corresponding to the thermistor body; a second portion continuous with the first portion, positioned corresponding to the conductive wire, and having a thickness different from a thickness of the first portion; The temperature sensor according to claim 3.

12. the second case includes a portion located on the first portion and in contact with the measurement object, in a first cross section including the thermistor body, the first case, and the portion of the second case, the thickness of the first portion is smaller than the thickness of the second portion; In a second cross section perpendicular to the first cross section, the thickness of the first portion is greater than the thickness of the second portion. The temperature sensor of claim 11.

13. At the first cross section, the thickness of the portion of the second case is greater than the thickness of the first portion. The temperature sensor of claim 12.

14. At the second cross section, the thickness of the first portion is greater than the thickness of the portion of the second case. The temperature sensor of claim 13.

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