Temperature sensor, and rotary electric machine

Abstract

To provide a temperature sensor that can guarantee accuracy of a detection temperature, in addition to enabling making a thickness of a thermo-sensitive part, for example, equal to or less than 1 mm.SOLUTION: A temperature sensor (1) comprises: a thermo-sensitive body (11); a sensor element (10) that includes a pair of first electric wires (13) to be electrically connected to the thermo-sensitive body (11); a pair of lead frames (30) that is electrically connected to each of the pair of first electric wires (13); a second electric wire (20) that is electrically connected to each of the pair of lead frames (30); a coating body (40) that is composed of a resin material encapsulating an entire part of the sensor element and the lead frame (30), and a part of the second electric wire (20), in which at least one of the lead frame (30) is extended forward (F) with respect to the thermo-sensitive body (11), and includes a protrusion part (33) toward other of the lead frame (30) in a portion to be extended.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a temperature sensor and a rotating electric machine used in a vehicle or the like.

Background Art

[0002] Temperature sensors are used in various applications, and there is a demand for a thin temperature sensor with a small thickness dimension. The thin temperature sensor is used, for example, by being inserted into a narrow space.

[0003] Patent Document 1 discloses a thin temperature sensor capable of reducing the thickness dimension and increasing the contact area with the object to be measured, thereby improving the temperature detection accuracy. The temperature sensor of Patent Document 1 includes an inner layer formed by curing or solidifying a pair of sheet-shaped inner layer materials made of a resin material, and an outer layer formed by a pair of sheet-shaped outer layer materials having flat surfaces on both sides made of a resin material. In the temperature sensor of Patent Document 1, the thermistor element, the lead wire, and the connection portion between the lead wire and the lead wire are covered by the inner layer and sandwiched and covered between the pair of outer layers, and the surfaces of the pair of outer layers are flat including the portions corresponding to the thermistor element as a heat-sensitive body, the lead wire, and the connection portion between the lead wire and the lead wire. As an example, the thickness of the inner layer and the outer layer in Patent Document 1 is such that the inner layer is 1 mm to 1.25 mm and the outer layer is 0.25 mm × 2 (sheets) = 0.5 mm. And according to Patent Document 1, a temperature sensor having flexibility and capable of being bent with a thickness of about 1.5 mm is provided.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] For example, there is a need for a temperature sensor thinner than 1.5 mm disclosed in Patent Document 1. However, simply making it thinner is not enough, and it is necessary to ensure the accuracy of the detected temperature required for a temperature sensor. Therefore, an object of the present invention is to provide a temperature sensor capable of ensuring the accuracy of the detected temperature in addition to being able to make the thickness of the heat-sensitive part, for example, 1 mm or less.

Means for Solving the Problems

[0006] The temperature sensor of the present invention includes a pair of lead frames arranged at intervals from each other, a sensor element including a heat-sensitive body and a pair of first electric wires electrically connected to the heat-sensitive body, a second electric wire electrically connected to each of the pair of lead frames, and a coating made of a resin material that encapsulates the entire sensor element and the lead frames, as well as a part of the second electric wire. At least one of the lead frames is provided with a protrusion directed toward the other lead frame.

[0007] In the temperature sensor of the present invention, preferably, each of the pair of first electric wires is electrically connected at one end side to each of the pair of lead frames at a connection site, and the protrusion is formed on the other end side of the lead frame with respect to the connection site.

[0008] In the temperature sensor of the present invention, a preferred protrusion is also formed at the other end of the lead frame.

[0009] In the temperature sensor of the present invention, a preferred protrusion is formed on both of the pair of lead frames.

[0010] In the temperature sensor of the present invention, the pair of lead frames are arranged along a first direction and are spaced apart in a second direction orthogonal to the first direction. Each of the preferred pair of lead frames has, a narrow portion that recedes outward in the second direction, a first wide portion that is larger in dimension in the second direction than the narrow portion and is continuous rearward of the narrow portion, a second wide portion that is larger in dimension in the second direction than the narrow portion and forms a protruding portion that is continuous forward of the narrow portion, and the heating element is disposed between the pair of narrow portions in the second direction.

[0011] In the temperature sensor of the present invention, the preferred pair of first electric wires are electrically connected to each of the pair of first wide portions.

[0012] In the temperature sensor of the present invention, the preferred coating body has a first portion where the sensor element and the lead frame are provided, and a second portion where the pair of second electric wires are provided, and both the first portion and the second portion are flat, and the dimension in the thickness direction of the first portion is smaller than that of the second portion, the first portion and the second portion have a flat surface on one side in the thickness direction, and have a step on the other side in the thickness direction.

[0013] The preferred coating body in the temperature sensor of the present invention has a wall thickness of the first portion of less than 1.0 mm.

[0014] The preferred coating body in the temperature sensor of the present invention has an inner layer made of an inner layer material that directly seals the sensor element, the lead frame, and a part of the second electric wires, and an outer layer that covers the inner layer and is made of an outer layer material having a higher melting point than the inner layer material, and the inner layer is made of the welded inner layer material, the outer layer is continuous as the outer layer material at the front and is attached to the inner layer.

[0015] A preferred inner layer material in the temperature sensor of the present invention is composed of at least one of PTFE (polytetrafluoroethylene), PFA (perfluoroalkoxyalkane), and FEP (perfluoroethylene-propene copolymer). The outer layer material is made of polyimide (PI).

[0016] The present invention provides a rotating electric machine including a temperature sensor composed of any of the above.

Effects of the Invention

[0017] According to the present invention, in addition to being able to make the thickness of the heat-sensitive portion 1 mm or less, a temperature sensor capable of ensuring the accuracy of the detected temperature can be provided.

Brief Description of the Drawings

[0018]

Figure 1

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Figure 15

Mode for Carrying Out the Invention

[0019] [Overall Configuration of Temperature Sensor 1: FIGS. 1 to 3] Hereinafter, the temperature sensor 1 according to the embodiment will be described with reference to the accompanying drawings. As shown in FIG. 1, the temperature sensor 1 includes a sensor element 10 (not shown in FIG. 1) described later, a first portion 3 in which the sensor element 10 is disposed, a second portion 5 in which the second electric wire 20 is disposed, and a flat covering 40 including an inclination 4 connecting the first portion 3 and the second portion 5. Both the first portion 3 and the second portion 5 are flat, but have different dimensions in the thickness direction T. For this reason, the inclination 4 forms a step between the first portion 3 and the second portion 5. Since the temperature sensor 1 can make the thickness of the first portion 3 directly related to temperature detection 1 mm or less, it can detect the temperature of a detection object facing a narrow space. Further, the temperature sensor 1 has rigidity and elasticity in the first portion 3, so that it has the rigidity required as the temperature sensor 1 and can press the first portion 3 against the detection object. Hereinafter, in the temperature sensor 1, the length direction (first direction) L, the width direction W (second direction), and the thickness direction T are defined as shown in FIG. 1 and FIG. 2 described later. The length direction (first direction) L and the width direction W (second direction) are orthogonal to each other. Further, in the temperature sensor 1, the side of the length direction L where the heat-sensitive element 11 is provided is defined as the front or the front (F), and the side from which the second electric wire 20 is drawn out is defined as the rear or the rear (R). The side where the inclination 4 is formed is defined as the front surface, and the surface facing the front surface is defined as the back surface. Hereinafter, the configuration of the temperature sensor 1 will be described, and then the operation and effects of the temperature sensor 1 will be mentioned.

[0020] As shown in FIG. 2, the temperature sensor 1 includes a sensor element 10, a pair of second electric wires 20, 20 electrically connected to the respective ones of the pair of first electric wires 13, 13 of the sensor element 10 via lead frames 30, 30, and a pair of lead frames 30, 30 electrically connected to the respective ones of the pair of first electric wires 13, 13 and also electrically connected to the respective ones of the pair of second electric wires 20, 20. Further, the temperature sensor 1 includes a flat covering body 40 that covers the sensor element 10, the entire pair of lead frames 30, 30, and a part of the periphery of the second electric wire 20. Here, covering the periphery means covering the edges when viewed in plan in addition to the front and back surfaces.

[0021] [Sensor element 10: Refer to FIG. 3] The sensor element 10 is formed in a rectangular parallelepiped shape, and includes a heat-sensitive element 11 that detects the temperature of an object, electrodes 12, 12 formed on each of the two opposing surfaces of the heat-sensitive element 11, a pair of first electric wires 13, 13 electrically connected to the heat-sensitive element 11 via the electrodes 12, 12, and a sealing body 16 that covers a part of the heat-sensitive element 11, the electrodes 12, 12, and the connection portion side of the electrodes 12, 12 of the pair of first electric wires 13, 13. The sensor element 10 is disposed in the first portion 3 of the temperature sensor 1 and is sealed inside the covering body 40.

[0022] The heat-sensitive element 11 is made of a metal oxide or a metal having the property that its electrical resistance value changes with temperature change. While passing a current through the heat-sensitive element 11 via a pair of first electric wires 13, 13, the voltage between the electrodes 12, 12 of the heat-sensitive element 11 is measured, the resistance value is obtained from Ohm's law (E = IR), and the temperature is detected. As the metal oxide, a thermistor (Thermally Sensitive Resistor) is preferably used, and typically an NTC thermistor (Negative Temperature Coefficient Thermistor) having a negative temperature coefficient is used. As the metal, platinum (for example, Pt100; JIS-C1604) is preferably used.

[0023] The electrodes 12 electrically connect the heat-sensitive element 11 and the first electric wires 13, 13, and are preferably made of a noble metal such as gold or platinum. The first electric wires 13, 13 are conductive wires for passing a constant current through the heat-sensitive element 11. One end 13a thereof is connected to the electrode 12 of the heat-sensitive element 11, and the other end 13b is connected to a pair of lead frames 30, 30 described later. For the first electric wires 13, 13, a metal material with high electrical conductivity, typically copper, is used. For the first electric wire 13, a Dumet Wire is preferably used. The Dumet Wire refers to a composite wire in which an inner layer made of an iron-nickel alloy and an outer layer made of copper are clad.

[0024] The pair of first electric wires 13, 13 extend rearward (R) in the length direction L. And the interval in the width direction W between the other ends 13b, 13b of this pair of first electric wires 13, 13 widens rearward (R). In the present embodiment, the case where the interval between the pair of first electric wires 13, 13 widens toward the rear (R) side is exemplified, but it is not limited to this shape as long as the pair of first electric wires 13, 13 and the lead frames 30, 30 described later can be connected by welding or the like. For example, the first electric wires 13, 13 may be extended in parallel at the one end 13a side, and only the other ends 13b, 13b and the vicinity thereof may be bent at a right angle in the width direction and connected to the lead frames 30, 30.

[0025] The sealing body 16 is provided to suppress chemical and physical changes in the heating element 11 by surrounding the heating element 11 and sealing it in an airtight state. Glass is preferably used as the material of the sealing body 16, but a resin material can also be used depending on the environment in which the temperature sensor 1 is used, or the sealing body 16 can be omitted. In particular, when dumet wires are used for the first electric wires 13, 13, since the coefficient of linear expansion of the iron-nickel alloy approximates that of glass, if glass is used for the sealing body 16, damage to the sealing body 16 due to thermal expansion of the first electric wires 13, 13 can be prevented.

[0026] Note that the shape of the sealing body 16 is exemplified by a spindle shape as a preferred form, but other shapes such as a spherical shape may also be used.

[0027] In order to obtain a thin temperature sensor 1, an element with a small size is used for the sensor element 10. To obtain a temperature sensor 1 with a thickness of 1 mm or less, the wire diameter D13 of the first electric wire 13, the minor axis SA and the major axis LA of the sealing body 16 including the heating element 11 are selected from the following ranges as an example. The dimension of the minor axis SA involved in the thickness of the first portion 3 in the sealing body 16 is First electric wire 13: Wire diameter D13; 0.07 to 0.15 mm, preferably 0.10 to 0.12 mm Sealing body 16: Minor axis SA; 0.4 to 0.8 mm, preferably 0.45 to 0.65 mm Major axis; 0.8 to 1.4 mm, preferably 0.9 to 1.3 mm

[0028] [Second electric wire 20: Refer to FIG. 2] The pair of second electric wires 20, 20 are electric wires for passing current through the first electric wires 13, 13 and making electrical connection with the outside. The second electric wire 20 includes a core wire 21 and a coating layer 23 having electrical insulation that covers the periphery of the core wire 21. For the core wire 21, either a single wire or a stranded wire formed by twisting a plurality of thin conductors can be adopted, but it is preferable to use a stranded wire with high flexibility and easy to bend. Regarding the material of the core wire 21, there is no limitation as long as the purpose can be achieved, but preferably copper or a copper alloy with excellent conductivity is used.

[0029] The coating layer 23 is composed of a resin material having electrical insulation properties. Although it will be described in detail later, when the coating body 40 is formed by welding with heat, it is preferable to use a fluororesin. Fluororesins are excellent in water and oil repellency, chemical resistance, and electrical insulation. Examples of fluororesins include PTFE (polytetrafluoroethylene), PFA (perfluoroalkoxyalkane), and FEP (perfluoroethylene-propene copolymer). The melting points of PTFE, PFA, and FEP are 327°C, 310°C, and 260°C, respectively, and are appropriately selected according to the heating temperature when welding the resin material constituting the coating body 40. For example, when the welding of the coating body 40 is performed at a temperature exceeding 300°C, it is preferable to form the coating layer 23 with PTFE or PFA.

[0030] The second electric wire 20 is located at the second part 5 of the temperature sensor 1. Therefore, since the wire diameter of the second electric wire 20 is not related to the thickness of the first part 3 which is the heat-sensitive part, its wire diameter is arbitrary. However, in addition to passing an electric current through the first electric wire 13, strength against bending and the like is also required. Therefore, the wire diameter of the core wire 21 needs to be considerably larger than that of the first electric wire 13. Thus, as an example, the wire diameter of the core wire 21 is selected from the range of 0.5 to 1.5 mm. It is not easy to directly electrically connect the core wire 21 with a wire diameter in this range and the first electric wire 13. Therefore, the first electric wire 13 is electrically connected to the second electric wire 20 via the lead frame 30.

[0031] [Lead frame 30: Refer to FIGS. 5 and 6] In addition to the electrical function of electrically connecting the first electric wire 13 and the second electric wire 20, the lead frame 30 imparts mechanical functions such as rigidity and elasticity to the first portion 3. That is, in the temperature sensor 1, the lead frame 30 exhibits two functions. Since the lead frame 30 is also disposed in the first portion 3, when the thickness thereof is in the range of 0.05 to 0.15 mm, particularly when the thickness of the temperature sensor 1 is 0.1 mm or less, it is selected from the range of 0.05 to 0.1 mm. The lead frame 30 is composed of a plate-like metal material having conductivity. When conductivity is emphasized, copper or a copper alloy is preferably adopted, and when mechanical properties are emphasized, steel, particularly stainless steel, is preferably adopted. Although approximate values, when comparing Young's modulus, copper is 130 GPa, steel is 200 GPa, and PTFE is 400 MPa, and the superiority of the mechanical properties of the metal material can be easily understood. Although an example in which a pair of lead frames 30, 30 in the present embodiment are arranged parallel to each other is shown, they may be inclined with respect to each other as long as a distance therebetween is ensured.

[0032] The lead frame 30 is manufactured by punching a metal plate having a desired plate thickness. This lead frame 30 includes a first wide portion 31 on the side connected to the second electric wire 20, a narrow portion 32 continuous with the first wide portion 31, and a second wide portion 33 continuous with the narrow portion 32. The first wide portion 31 and the second wide portion 33 have dimensions W31, 33 in the same width direction W. The narrow portion 32 has a dimension W32 in the width direction W that is smaller than those of the first wide portion 31 and the second wide portion 33, and one edge 34 in the width direction W forms a straight line. As a result, the other edge 35 has irregularities in the width direction W, constituting a recess 39. As will be described later, the heat-sensitive body 11 of the sensor element 10 is disposed between the recesses 39, 39 of the pair of lead frames 30, 30. When comparing the first wide portion 31 and the second wide portion 33, the dimension in the length direction L of the second wide portion 33 is smaller than the dimension in the length direction L of the first wide portion 31. Note that the dimensions in the thickness direction T of the first wide portion 31, the narrow portion 32, and the second wide portion 33 are the same.

[0033] The lead frame 30 may be made of a solid metal material, or may be subjected to a surface treatment such as plating.

[0034] [Cover 40: Refer to FIGS. 4 and 2] The cover 40 covers a part of the sensor element 10, a pair of lead frames 30, 30, and the second wire 20 including the second connection part SC2, and seals the inside. By providing the cover 40, the liquid resistance performance and electrical insulation performance with respect to the sensor element 10 are ensured. The cover 40 is required to have heat resistance with stable physical properties with respect to the detected temperature. The cover 40 in the first part 3 is formed by using a film made of a resin material, so that a thin thickness of 1 mm or less, preferably 0.7 mm or less can be realized. The cover 40 can be composed of a single layer of the same material, but in order to ensure higher liquid resistance performance and electrical insulation performance, it can be composed of a plurality of layers, for example, two layers of an inner layer and an outer layer covering the inner layer. Hereinafter, an example in which the cover 40 is composed of two layers of an inner layer 41 and an outer layer 43 will be described with reference to FIG. 4. Note that the liquid resistance performance refers to a measure for preventing liquids such as water and oil from entering the inside of the temperature sensor 1. Further, hereinafter, the sensor element 10, a pair of lead frames 30, 30, and the second wire 20 including the second connection part SC2 are abbreviated as the sensor element 10 etc.

[0035] <Regarding the inner layer 41> The inner layer 41 directly covers the sensor element 10 etc. and seals the sensor element 10 etc., thereby ensuring only the liquid resistance performance. The inner layer 41 preferably forms a sealing structure by welding a film-like resin material, and the portion where there is no sensor element 10 etc., for example, between the pair of lead frames 30, 30 is occupied by the resin material. According to JIS K 6900, for a resin material, a film is defined as a film-like material with a thickness of less than 0.25 mm, and a sheet is defined as a plate-like material with a thickness of 0.25 mm or more. However, in this embodiment, the film is treated as including a sheet. However, it does not mean including a sheet with a thickness exceeding, for example, 1.0 mm, which is contrary to the purpose of the thin type in this embodiment.

[0036] The inner layer 41 is preferably composed of at least one of the above-described fluororesin materials. When the inner layer 41 is formed by welding, it is preferable to use FEP having a lower melt viscosity than other fluororesins. By doing so, the inner layer 41 can densely seal the sensor element 10 and the like. When using FEP to form the inner layer 41, it is preferable to use PTFE having a higher melting point than FEP for the coating layer 23 of the second electric wire 20. As long as the thin temperature sensor 1 can be obtained, the thickness of the inner layer 41 is arbitrary, but as an example, a thickness in the range of 0.2 to 0.5 mm is selected.

[0037] On both sides in the width direction W, the inner layer 41 is sealed from the outside only by the welded inner layer 41. On the other hand, on the side R after the second electric wire 20 is pulled out, there are a portion sealed from the outside only by the welded inner layer 41 and a portion where the inner layer 41 seals around the coating layer 23 of the second electric wire 20. There is concern about the liquid resistance performance at the boundary between the coating layer 23 and the inner layer 41 in the portion where the inner layer 41 seals around the coating layer 23 of the second electric wire 20 compared to the portion sealed only by the inner layer 41. However, when both the coating layer 23 and the inner layer 41 are made of resin materials, a high bonding strength by welding can be obtained compared to sealing a metal material with a resin material, so it is easy to ensure liquid resistance performance. That is, when comparing the linear expansion coefficient of the resin material and the linear expansion coefficient of the metal material, the linear expansion coefficient of the resin material is several times larger than the linear expansion coefficient of the metal material. For example, when this temperature sensor 1 is used in an environment where frequent temperature changes occur, minute gaps are likely to occur at the boundary between the resin material and the metal material. On the other hand, in the joint portion between resin materials, since the linear expansion coefficients are relatively close, gaps are less likely to occur like at the boundary between the resin material and the metal material, and liquid resistance performance can be ensured. In particular, when both the coating layer 23 and the inner layer 41 are made of the same type of fluororesin, high liquid resistance performance can be obtained.

[0038] <Regarding the outer layer 43> The outer layer 43 is laminated on the inner layer 41 to cover the sensor element 10 etc. via the inner layer 41. The inner layer 41 solely ensures the withstand voltage performance in the thickness direction T in the first part 3 of the temperature sensor 1. For the outer layer 43, PI (polyimide), PEEK (polyetheretherketone), and PPS (polyphenylene sulfide) are preferably used. When it comes to withstand voltage, while PTFE, which is a fluororesin, is 20 kV / mm, PPS is 200 - 300 kV / mm, and PI is 380 - 400 kV / mm. PI has a thermal decomposition temperature of 500°C or higher, and by melting, for example, FEP that constitutes the inner layer 41, reliable bonding between the outer layer 43 and the inner layer 41 is achieved.

[0039] As long as a thin - type temperature sensor 1 can be obtained, the thickness of the outer layer 43 is arbitrary, but as an example, it can be selected from a thickness of 5 - 50 μm, preferably from a thickness of 15 - 35 μm. As an example, a PI film with a thickness of 5 μm is available on the market.

[0040] <Relationship between the inner layer 41 and the outer layer 43> The forming methods of the inner layer 41 and the outer layer 43 are arbitrary, but preferably, the inner layer 41 is formed by welding with the sensor element 10 etc. by heating, and the outer layer 43 is attached to the inner layer 41 along with the welding of the inner layer 41. An example of a preferred forming method for the inner layer 41 and the outer layer 43 will be described later, but at least the resin material constituting the inner layer 41 has a lower melting temperature than the resin material constituting the outer layer 43.

[0041] The outer layer 43 is formed, for example, by folding a single film. Specifically, the front (F) side in the length direction L of the rectangular film is folded. This folded portion forms the end 3a of the first portion 3, which is the front (F) end in the length direction L of the temperature sensor 1. On the other hand, the ends on the rear (R) side in the length direction L of the folded film are aligned with each other and adhered to form the end 5a of the second portion 5. As a result, at both ends in the length direction L of the temperature sensor 1, the end 3a, which is the front (F) side end, is formed only by the outer layer 43, and the end 5a side, which is the rear (R) side, is formed so as to sandwich the pair of second electric wires 20, 20 between the folded films. Therefore, from the end 5a side, the second electric wires 20, 20 protrude to the outside of the second portion 5. When viewed from the rear (R) side of the temperature sensor 1, the outer layer 43 is located at both ends in the thickness direction T of the end 5a, and the inner layer 41 and the second electric wires 20, 20 are located therebetween. Also, at both ends in the width direction W, the outer layer 43 is located at both ends in the thickness direction T, and the inner layer 41 is located therebetween. This is the same for the first portion 3 and the second portion 5.

[0042] <Dimensions in the thickness direction T of the covering 40: See FIG. 4> The dimension T1 in the thickness direction T of the first portion 3 in the covering 40 is smaller than the dimension T2 in the thickness direction of the second portion 5. And the front surface side of the temperature sensor 1 forms a plane, and an inclination 4 is formed on the back side.

[0043] [Relationship between the sensor element 10 and the lead frames 30, 30: See FIGS. 6, 2 and 4] The sensor element 10 is disposed between the lead frames 30, 30 in a plan view. The other ends 13b, 13b of the first electric wires 13, 13 are electrically connected to the lead frames 30, 30, respectively, for example, by welding. Specifically, the first electric wires 13, 13 extend toward the rear (R) in the length direction L with reference to the position of the heat-sensitive body 11, and the distance between both of them continuously widens toward the rear (R). The first electric wires 13, 13 are connected to the lead frames 30, 30 by the first connection portions SC1 at the first wide portions 31 away from the narrow portion 32 in the rear (R) side in the length direction L. The first electric wires 13, 13 and the lead frames 30, 30 are arranged symmetrically with respect to the central axis C.

[0044] As shown in FIG. 2, in a plan view, the sealing body 16 including the heat-sensitive body 11 is disposed between the lead frame 30, the narrow portion 32 of the lead frame 30, and the narrow portion 32. Specifically, the sealing body 16 including the heat-sensitive body 11 is on the rear (R) side in the length direction L from the second wide portion 33 and is disposed between the recesses 39, 39 of the pair of lead frames 30, 30. By adopting this arrangement, while maintaining the distance between the pair of lead frames 30, 30 and the sealing body 16, the dimension in the width direction W occupied by the pair of lead frames 30, 30 can be reduced, which contributes to the miniaturization of the temperature sensor 1 in the width direction W. The space between the heat-sensitive body 11 and the like and the narrow portions 32, 32 is sealed with the resin material constituting the inner layer 41 as described above, and the heat-sensitive body 11 and the like and the first electric wires 13, 13 are positioned by the resin material at the central axis C between the lead frames 30 and the lead frames 30. As shown in the cross-sectional side view shown in FIG. 4, the heat-sensitive body 11 and the like are arranged so as to overlap the lead frames 30, 30 and are disposed between the lead frames 30 and the lead frames 30.

[0045] Here, if the length of the first electric wire 13 is L13 and the distance between the pair of lead frames 30, 30 is G1, then the length of the first electric wire 13 and the length between the pair of lead frames 30, 30 are in the relationship of L13 > G1, particularly in the relationship of L13 >> G1. That is, the first electric wire has a surplus length compared to the distance G1 between the pair of lead frames 30, 30. The effect of the length L13 having a surplus length with respect to the distance G1 will be described in detail later. Incidentally, if the angle formed by the first electric wire and the central axis C is θ13, it has the relationship of L13 × sinθ13 ≒ 1 / 2G1.

[0046] [Lead frames 30, 30 and second electric wires 20, 20: Figure 2] The pair of second electric wires 20, 20 are electrically connected to the lead frames 30, 30 by, for example, welding or the like. Specifically, one ends 20a, 20a of the pair of second electric wires 20, 20 are connected via a second connection site SC2 formed by resistance welding or the like on the rear (R) side of the first wide portion 31 of the lead frames 30, 30. In this way, since the lead frames 30, 30 and the pair of second electric wires are connected via the second connection site SC2, the sensor element 10 and the pair of second electric wires 20, 20 are electrically connected.

[0047] [Manufacturing procedure of temperature sensor 1: Refer to Figures 7, 8, 9] Next, the procedure for manufacturing the temperature sensor 1 will be described. This manufacturing procedure includes a first step of electrically connecting the sensor element 10 and the second electric wires 20, 20 to the lead frames 30, 30, and a second step of forming the covering 40. Hereinafter, the first step and the second step will be described in order, but it is assumed that the sensor element 10 has already been obtained.

[0048] [First step: Refer to Figures 7, 8] The first step includes a first A step (STEP1A) of connecting the sensor element 10 to the lead frames 30, 30, and a first B step (STEP1B) of connecting the second electric wires 20, 20 to the lead frames 30, 30 to which the sensor element 10 is connected.

[0049] <First A Step (STEP1A)> Prepare the sensor element 10 and the lead frames 30, 30. After positioning the first electric wires 13, 13 at predetermined positions on the lead frames 30, 30, the first electric wires 13, 13 and the lead frames 30, 30 are connected. The means of this connection is arbitrary, and welding such as resistance welding, soldering, etc. are adopted. Resistance welding sandwiches the metal to be welded with electrodes and applies pressure, and melts and cools and solidifies the base material by the resistance heat generated when an electric current flows between the electrodes, and belongs to the category of pressure welding. In the case of this embodiment, the heat-generating portions of the first electric wire 13 and the lead frame 30 are melted and solidified, so that the first electric wire 13 and the lead frame 30 are electrically joined. The melted and cooled and solidified portions are called nuggets, and the first connection site SC1 between the first electric wire 13 and the lead frame 30 is composed of nuggets. When the first electric wires 13, 13 are connected to the lead frames 30, 30, as shown in FIG. 8, the lead frames 30, 30 may be connected by a so-called carrier, or may be separated. In order to maintain the mutual positional relationship of the lead frames 30, 30, as shown in FIG. 8, it is preferable that the lead frames 30, 30 are connected by the carrier C. In FIG. 8, only a pair of lead frames 30, 30 are connected to the carrier C, but the first A step can be executed in a state where a plurality of pairs of lead frames 30, 30 are connected by a common carrier C.

[0050] <First B Step (STEP1B)> Next, in the first B step, the second electric wires 20, 20 are connected to the lead frames 30, 30. In this connection, after positioning the second electric wires 20, 20 at predetermined positions on the lead frames 30, 30, the core wires 21, 21 of the second electric wires 20, 20 and the lead frames 30, 30 are connected. The same connection means as in the first A step is adopted for this connection, and it is preferable that the lead frames 30, 30 are connected to the carrier C.

[0051] Hereinafter, the one in which the first electric wires 13, 13 and the second electric wires 20, 20 are connected to the lead frames 30, 30 is referred to as the sensor connector 7. In this embodiment, an example in which the second electric wires 20 and 20 are connected to the lead frames 30 and 30 after the first electric wires 13 and 13 are connected to the lead frames 30 and 30 has been described. However, the first electric wires 13 and 13 may be connected to the lead frames 30 and 30 after the second electric wires 20 and 20 are connected to the lead frames 30 and 30. Also, the first electric wires 13 and 13 and the second electric wires 20 and 20 may be connected to the lead frames 30 and 30 simultaneously.

[0052] [Second Step: Refer to FIGS. 9 and 10] The second step includes a second A step (STEP2A) of melting a part of the resin film 45 covering the front and back of the sensor connector 7 and welding the sensor connector 7 to the covering body 40, and a second B step (STEP2B) of removing the surplus portion of the covering body 40.

[0053] <Second A Step (STEP2A): Refer to FIGS. 9 and 10>[ Prepare the resin film 45 constituting the covering body 40, and arrange the sensor connector 7 at a predetermined position on the resin film 45. By folding the resin film 45 in the length direction L at the folding line RCL, the front and back of the sensor connector 7 are covered with the resin film 45. Corresponding to the fact that the covering body 40 has two layers, an inner layer 41 and an outer layer 43, as shown in FIG. 10(a), the resin film 45 includes two films, a first film 46 and a second film 47. The first film (inner layer material) 46 corresponds to the inner layer 41, and the second film (outer layer material) 47 corresponds to the outer layer 43. The first film 46 and the second film 47 cover the front and back of the sensor connector 7 in a laminated state as shown in FIG. 10(b). FIG. 10(a) shows the first film 46 and the second film 47 separated from each other to clarify their existence. The same applies to FIG. 10(b). Note that the first film 46 and the second film 47 are manufactured with dimensions in the width direction W larger than those of the covering body 40.

[0054] As an example, assume that the inner layer 41 is made of FEP (perfluoroethylene - propene copolymer) and the outer layer 43 is made of PI (polyimide). In this case, preferably, the first film 46 is made of FEP, and the second film 47 includes a first layer 47A made of PI and a second layer 47B made of FEP formed on one surface of the first layer 47A. The second film 47 is laminated with the first film 46 such that the second layer 47B made of the same resin material as the first film 46 is in contact with the first film 46. When joining the first film 46 and the second film 47 by welding, the second layer 47B is melted and solidified together with the first film 46, which can contribute to improving the joining strength between the inner layer 41 and the outer layer 43. The first film 46 and the second film 47 to be laminated may be temporarily welded partially so that they do not shift relative to each other.

[0055] <Second B Step (STEP2B): Refer to FIGS. 9 and 10> After arranging the sensor connector 7 at a predetermined position on the resin film 45, the resin film 45 is folded back in the length direction L, and heat welding is performed in a state where the front and back of the sensor connector 7 are covered with the resin film 45. The heat welding is performed by heating to a temperature exceeding the melting point of the first film 46 and the second layer 47B of the second film 47. However, this heating temperature is preferably less than the melting point of the first layer 47A of the second film 47.

[0056] This heat welding preferably involves pressing by a press for the purpose of improving the joining strength by welding. The mold used for pressing may have planes on both of the two surfaces to which pressure is applied, or grooves may be formed on at least one of the surfaces. When both of the two surfaces are planes, it is not possible to mechanically restrain in the width direction W during heat welding, so there is a possibility that the mutual distance between the lead frames 30, 30 and the mutual distance between the second wires 20, 20 will become wider. On the other hand, if heat welding is performed using a mold with grooves formed on at least one surface, the lead frames 30, 30, etc. can be mechanically restrained in the width direction W, so it is possible to suppress the widening of their mutual distances.

[0057] The temperature sensor 1 illustrated in FIG. 1 is thermally welded using a pair of molds, one with a groove formed on one side and the other having a flat surface. That is, in the temperature sensor 1, the side that is the flat surface of the covering 40 is pressed by a mold having a flat surface, while the side with a step is pressed by a mold with a groove formed therein. A groove is formed in the mold corresponding to the second portion 5 where the second wire 20 is disposed.

[0058] Since the resin film 45 is made wider than the covering 40, both sides in the width direction W are cut at the cutting lines CL to remove both sides in the width direction W. Thus, the temperature sensor 1 having a desired dimension is obtained.

[0059] [Effect] The effects exhibited by the temperature sensor 1 will be described. <First effect: Thermal stress relaxation by the lead frames 30> In the temperature sensor 1, the sealing body 16 including the heat-sensitive body 11 is provided with lead frames 30, 30 on both sides in the width direction W, and second wide portions (protruding portions) 33, 33 that protrude forward (F) toward the center in the width direction W are provided. Therefore, even if the temperature rises or falls during temperature detection and thermal expansion or thermal contraction occurs in the covering 40 due to the small dimension in the thickness direction T, the lead frames 30, 30 relax the thermal stress applied to the heat-sensitive body 11 via the inner layer 41, ensuring the accuracy of the detected temperature.

[0060] <Second effect: Excess length of the first wire 13: Refer to FIG. 11> According to the temperature sensor 1, the first electric wires 13, 13 have an excess length L13 with respect to the interval G1 between the lead frames 30, 30. Therefore, even if the interval G1 between the lead frames 30, 30 widens as shown by the two-dot chain line in FIG. 10 during the manufacturing process of the temperature sensor 1 and during temperature detection, it is possible to prevent the first electric wire 13 from breaking. Further, it is possible to prevent the first connection portion SC1 between the first electric wire 13 and the lead frame 30 from breaking. Thereby, the temperature sensor 1 can continue stable temperature detection while being thin. In particular, since the thin temperature sensor 1 has insufficient mechanical strength against external forces and is likely to be displaced with respect to the lead frames 30, 30 when receiving an external force, it is very significant to provide the first electric wire 13 with an excess length.

[0061] In the example shown here, the length L13 has a considerable excess length with respect to the interval G1, but the excess length is sufficient if it can correspond to the maximum expansion of the assumed interval G1. Although it is necessary to consider the dimensions of the sealing body 16 and the like, if it has the relationship of 2 × L13 > G1, it can correspond to the expansion of the assumed lead frames 30, 30.

[0062] <The third effect: Sealing by the inner layer 41 and the outer layer 43> According to the temperature sensor 1 of the present embodiment, in addition to the entire sensor element 10 and the lead frame 30, the second connection portion SC2 between the lead frame 30 and the second electric wire 20 is also sealed by the inner layer 41. In particular, since the inner layer 41 is formed by welding a fluororesin, the temperature sensor 1 can ensure liquid resistance while having heat resistance. In addition, since the outer layer 43 is attached to the inner layer 41, a higher sealing ability can be realized. In particular, when PI is used as the outer layer 43, it is easy to ensure electrical insulation performance even if the covering 40 is made thin.

[0063] The covering 40 is formed by folding back a resin film 45 in front (F) where the heat-sensitive body 11 and the like are provided. Therefore, there is no joint portion by welding in the folded-back portion, and the second film 47 is continuous as it is, and there is no joint by welding at the front end portion of the covering 40, so that the intrusion of water, oil, etc. from the portion is prevented.

[0064] <Fourth Effect: Connection via Lead Frame 30> By connecting the first wire 13 with a small wire diameter and the core wire 21 with a large wire diameter via the lead frame 30, a reliable connection can be achieved. That is, the core wire 21 made of a stranded wire has irregularities on its surface, and it is difficult to obtain a sound connection state because the contact area with the core wire 21 of the first wire 13 is small. On the other hand, if it is the lead frame 30 with a flat surface, a sound connection state can be easily obtained regardless of whether it is the first wire 13 with a small wire diameter or the core wire 21 with a large wire diameter.

[0065] <Fifth Effect: Elasticity Imparted by Lead Frame 30> Since the lead frame 30 is provided in the first part 3 directly related to temperature detection, mechanical properties that cannot be obtained only by the coating 40 are imparted to the first part 3. Therefore, in addition to being able to insert the first part 3 into a narrow space without difficulty, temperature detection can be performed while the first part 3 maintains the required posture. In addition, since the first part 3 can be pressed against the detection object with an elastic force, it is easy to maintain the contact state of the first part 3 with the detection object even in an environment where vibration occurs, for example.

[0066] <Sixth Effect: Connection Position of the First Wire 13 to the Lead Frame 30> In the temperature sensor 1, the first wire 13 is connected to the first wide part 31 of the lead frame 30. The first wide part 31 has a larger dimension in the width direction W than the narrow part 32 and is less likely to bend. Therefore, even if the first part 3 is pressed against the detection object and bent, the first wide part 31 to which the first wire 13 is connected is less likely to bend, and it is easy to ensure the connection state at the first connection site SC1 of the first wire 13 to the lead frame 30.

[0067] <Seventh Effect: Combination of the First Part 3 and the Second Part 5> Since the dimension of the first part 3 directly related to temperature detection in the thickness direction T of the temperature sensor 1 is smaller than that of the second part 5, the first part 3 can be inserted even in a narrow space. On the other hand, since the dimension of the second part 5 in the thickness direction T can be increased, the second electric wire 20 having a wire diameter larger than the thickness of the first part 3 can be used.

[0068] [Modification example] In addition to the above, as long as the gist of the present invention is not deviated from, it is possible to select and discard the configurations described in the above embodiments, or to appropriately change them to other configurations. An example thereof will be described below. <Form of the covering 40: Refer to FIG. 12> The covering 40 described above has shown an example in which the dimension in the width direction W is constant, but the present invention is not limited to this. For example, as shown in FIG. 12(a), the dimension of the first part 3 in the width direction W can be made smaller than that of the second part 5. Thereby, temperature detection can be performed even for a narrow space in the width direction W. Further, as shown in FIG. 12(b), a protruding piece 48 having an increased dimension in the width direction W of a part of the second part 5 can be provided. By locking the protruding piece 48 or the like, the temperature sensor 1 can be positioned and fixed with respect to the object to be detected. Although not shown, a recess can also be formed in a part of the covering 40, contrary to the example of FIG. 12(b). Here, the width direction W has been mentioned, but in particular, the thickness direction T of the second part 5 can also be made into a shape suitable for the same purpose as the example of FIG. 12(b).

[0069] <Shape of the lead frame 30, etc.: FIGS. 13(a) to (c)> In the above description, the lead frame 30 with different dimensions in the width direction W has been described. However, as shown in Fig. 13(a), the present invention can also use a lead frame 30 with a constant dimension in the width direction W. Even in this lead frame 30, at least the above-described third and fourth effects can be achieved. As shown in Fig. 13(a), the position of the sealing body 16 including the heating element 11 and the like can be provided in front (F) of the lead frames 30, 30, or can also be provided behind (R) between the lead frames 30, 30. Note that the lead frame 30 with a constant dimension in the width direction W can have a low manufacturing cost.

[0070] Next, as shown in Fig. 13(b), the lead frame 30 is arranged in front (F) of the sealing body 16 including the heating element 11 and the like and across the entire width direction W. That is, for one lead frame 30, the above-described second wide portion 33 is omitted, while for the other lead frame 30, the protruding dimension of the second wide portion 33 can be increased. Thereby, the thermal stress in the length direction L applied to the heating element 11 can be further reduced.

[0071] Also, as shown in Fig. 13(c), a locking piece 37 can be provided by protruding a part of the second wide portions 33, 33 forward (F). The locking piece 37 serves as a resistance to the displacement of the lead frame 30 in the width direction W in the inner layer 41. When separating the lead frames 30, 30 from the carrier C, the separation position can be adjusted so that the locking piece 37 is formed. In addition, for the lead frame 30 shown in Fig. 13(c), the dimension in the length direction L of the narrow portion 32 can be reduced.

[0072] The example shown in Fig. 13(d) has a smaller dimension in the length direction L compared to the conventional lead frame 30. Thus, in the present invention, the lead frame 30 is not limited to being long and can also be short. In addition, in this example, one of the pair of first electric wires 13 is connected to the front surface of the lead frame 30, and the other is connected to the back surface of the lead frame 30.

[0073] The example shown in FIG. 13(e) is different from the previous examples in the position of the first wire 13 and the first connection site SC1 of the lead frame 30. That is, in this example, the first connection site SC1 is provided near the boundary between the first wide portion 31 and the narrow portion 32.

[0074] The example shown in FIG. 13(f) is opposite to the previous examples in the orientation of the sensor element 10. That is, while the first connection site SC1 between the first wire 13 and the lead frame 30 is in the front (F), the sealing body 16 including the heat-sensitive body 11 etc. faces the rear (R).

[0075] Also, in the present invention, the first portion 3 and the second portion 5 of the temperature sensor 1 are not limited to having a flat shape, and can also be a curved surface such as an arcuate surface, for example. Also, the use of the temperature sensor in the present invention is arbitrary. For example, it can be provided in a rotating electric machine mounted on an automobile to measure the temperature of the rotating electric machine.

[0076] Finally, the results of actually fabricating the temperature sensor according to the present invention and confirming its effects will be described. The sensor element 10 was connected to the lead frame in the form shown in FIG. 14 and a tensile load was applied. In FIG. 14, there are a lead frame NF without a protrusion, a lead frame 1st with a protrusion formed on the tip side of the lead frame, a lead frame 2nd having a protrusion with a larger protrusion amount than the lead frame 1st, a lead frame 3rd with the protrusion formed at a position away from the tip side, and a lead frame 4th with a protrusion formed only on one of the lead frames. The dimensions and shapes of the portions of these five lead frames excluding the protrusions are the same.

[0077] For the reference sensor, the first sensor, the second sensor, the third sensor, and the fourth sensor obtained by connecting the sensor elements to each of the five lead frames as described in the embodiments, the tensile stress generated in the first wires 13, 13 when cooled from 270°C to 40°C was determined by CAE (Computer Aided Engineering) analysis. The results are shown in FIG. 15. In FIG. 15, the X-axis and the Z-axis correspond to the length direction L and the thickness direction T, respectively.

[0078] From FIG. 15, it was confirmed that the tensile stress of any of the first sensor, the second sensor, the third sensor, and the fourth sensor is lower than that of the reference sensor.

Explanation of Reference Numerals

[0079] 1 Temperature sensor 3 First part 5 Second part 7 Sensor connector 10 Sensor element 11 Heat-sensitive body 12 Electrode 13 First wire 16 Sealing body 20 Second wire 21 Core wire 23 Coating layer 30 Lead frame 31 First wide part 32 Narrow part 33 Second wide part 34, 35 Edge 37 Locking piece 40 Coating body 41 Inner layer 43 Outer layer 45 Resin film 46 First film 47 Second film 47A First layer 47B Second layer 48 Protruding piece C Carrier SC1 First connection part SC2 Second connection part L Length direction T Thickness direction W Width direction

Claims

1. A pair of lead frames arranged at intervals from each other, a heat-sensitive element, and a pair of first electric wires electrically connected to the heat-sensitive element, a sensor element comprising: A second electric wire electrically connected to each of the pair of lead frames, The sensor element and the entire lead frame, and a covering made of a resin material that seals a part of the second electric wire, comprising: A temperature sensor, wherein at least one of the lead frames includes a protrusion directed toward the other lead frame.

2. Each of the pair of first electric wires is electrically connected at one end side to each of the pair of lead frames at a connection site, The protrusion is formed on the other end side of the lead frame with respect to the connection site, The temperature sensor according to claim 1.

3. The protrusion is formed at the other end of the lead frame, The temperature sensor according to claim 2.

4. The protrusion is formed on both of the pair of lead frames, The temperature sensor according to claim 1.

5. With the side where the heat-sensitive element is disposed being the front and the side where the first electric wire is drawn out being the rear, The pair of lead frames are arranged along a first direction and are arranged at intervals in a second direction orthogonal to the first direction, Each of the pair of lead frames, A narrow-width portion that recedes toward the outside in the second direction, A first wide-width portion having a larger dimension in the second direction than the narrow-width portion and continuous rearward of the narrow-width portion, A second wide-width portion that forms the protrusion having a larger dimension in the second direction than the narrow-width portion and continuous forward of the narrow-width portion, comprising: The heat-sensitive element is disposed between the pair of narrow-width portions in the second direction, The temperature sensor according to claim 1.

6. The pair of first electric wires, Are electrically connected to each of the pair of first wide-width portions, The temperature sensor according to claim 5.

7. The covering, A first portion where the sensor element and the lead frame are provided, A second portion where the pair of second electric wires are provided, comprising: Both the first portion and the second portion are flat, and the dimension in the thickness direction of the first portion is smaller than that of the second portion, The first portion and the second portion, One side in the thickness direction forms a plane, The other side in the thickness direction has a step, The temperature sensor according to claim 1.

8. In the covering, The wall thickness of the first part is less than 1.0 mm. The temperature sensor according to claim 7.

9. With the side where the heat-sensitive element is disposed being the front and the side from which the first electric wire is drawn out being the rear, The coating comprises an inner layer made of an inner layer material that directly seals the sensor element, the lead frame, and a part of the second electric wires, and an outer layer that covers the inner layer and is made of an outer layer material having a melting point higher than that of the inner layer material. The inner layer is made of the inner layer material that has been welded. The outer layer continues as the outer layer material at the front and is attached to the inner layer. The temperature sensor according to claim 1.

10. The inner layer material comprises at least one of PTFE (polytetrafluoroethylene), PFA (perfluoroalkoxyalkane), and FEP (perfluoroethylene-propene copolymer). The outer layer material is made of polyimide. The temperature sensor according to claim 9.

11. A rotating electrical machine comprising the temperature sensor according to any one of claims 1 to 10.

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