Temperature sensor

Abstract

To provide a temperature sensor which makes it difficult to peel a resin material sealing a heat sensitive element unit off from a metal plate, prevents positional displacement of the heat sensitive element unit, and enables more accurate temperature measurement.SOLUTION: A temperature sensor is provided, comprising a heat sensitive element unit 2, a pair of lead terminals 3 connected to the heat sensitive element unit, a metal plate 4 having the heat sensitive element unit installed on a top surface thereof, and a resin sealing unit 5 for sealing the heat sensitive element unit with resin on the metal plate, where the metal plate has a protruded portion 4a configured to be in contact with at least a side face of the heat sensitive element unit and protrude upward while being sealed by the resin sealing unit.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a temperature sensor that can provide high heat conductivity and durability when installed on an object to be measured. [Background technology]

[0002] Generally, a known temperature sensor is one in which a thermistor element such as a chip thermistor or a flake thermistor is attached to a crimp terminal (for example, Patent Document 1). This temperature sensor has a circular ring portion that can be screwed onto a crimp terminal, known as an R terminal. By inserting a screw into this portion and screwing it into a female thread on the object to be measured, the temperature sensor can be easily screwed onto the object to be measured.

[0003] In the above-mentioned conventional temperature sensor, a heat-sensitive element such as a chip thermistor mounted on a crimp terminal formed from a metal plate is protected by being sealed with resin. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2018-124125 Summary of the Invention [Problem to be solved by the invention]

[0005] The above conventional techniques still have the following problems. That is, in the above-mentioned conventional temperature sensors, a U-shaped wall is provided on the metal plate, which serves as a crimp terminal, and a thermal element is placed inside this wall and sealed with resin. However, in the case of a metal plate without such a wall, when the thermal element placed on the metal plate is sealed with resin by transfer molding, the resin material is formed on only one side of the metal plate, and there is a risk that the resin material will peel off due to the difference in linear expansion coefficients between the metal plate and the resin material. Furthermore, there is a problem that the thermal element on the metal plate may become misaligned during transfer molding. Furthermore, there is a demand for a temperature sensor that can measure temperatures with high accuracy by further improving the heat transfer and thermal response from the metal plate to the thermal element.

[0006] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a temperature sensor in which the resin material sealing the thermal element portion is less likely to peel off from the metal plate, and which can suppress positional misalignment of the thermal element portion and improve the accuracy of temperature measurement. [Means for solving the problem]

[0007] The present invention employs the following configuration to solve the above problems: That is, a temperature sensor according to a first invention includes a thermal element, a pair of lead terminals connected to the thermal element, a metal plate on the upper surface of which the thermal element is installed, and a resin sealing portion that seals the thermal element on the metal plate with resin, and the metal plate has a protrusion that contacts at least a side surface of the thermal element and protrudes upward when sealed in the resin sealing portion.

[0008] In this temperature sensor, the metal plate has a protrusion that protrudes upward and contacts at least the side of the thermal element while sealed in the resin sealing portion, and the protrusion is sealed into the resin sealing portion, thereby providing an anchor effect to prevent peeling and slipping out of the resin sealing portion. Furthermore, compared to conventional technology in which the thermal element and the metal plate are in contact only at the bottom of the thermal element, the temperature sensor of the present invention can transfer heat from the protrusion to at least the side of the thermal element, and the positioning effect of the protrusion can prevent misalignment of the thermal element during resin sealing.

[0009] A temperature sensor according to a second invention is the temperature sensor of the first invention, characterized in that the protrusion is formed to have a U-shaped cross section and covers the side surface to the top surface of the heat-sensitive element portion. In other words, in this temperature sensor, the protrusion is formed in a U-shaped cross section, covering the side and top of the thermal element, so that heat can be transferred from the protrusion to not only the side but also the top of the thermal element, and resin fills the opening of the protrusion, providing a greater anti-slip effect (anchor effect).

[0010] The temperature sensor of the third invention is characterized in that, in the first or second invention, the metal plate has an opening cut in a strip shape from the edge toward the thermal element portion, and at least a portion of the pair of lead terminals extends directly above the opening. That is, in this temperature sensor, at least a portion of the pair of lead terminals extends directly above the opening, so that heat is prevented from being transferred from the metal plate to the lead terminals and being released to the outside.

[0011] The temperature sensor of the fourth invention is characterized in that, in the third invention, the protrusion is formed by bending a strip-shaped portion of the metal plate with two cuts, and the opening is a portion that opens in the metal plate when the protrusion is formed by the bending process. In other words, in this temperature sensor, the opening is the part that opens in the metal plate when the protrusion is formed by bending processing, so the formation of the protrusion and the opening can be carried out simultaneously, thereby reducing the manufacturing process.

[0012] The temperature sensor according to the fifth invention is characterized in that, in any one of the first to fourth inventions, the protrusion has a recess, and the resin of the resin sealing portion is filled up to the recess. That is, in this temperature sensor, the protruding portion has a recessed portion, and the resin of the resin sealing portion is filled up to the recessed portion, so that an even higher effect of preventing the sensor from coming off can be obtained. [Effects of the Invention]

[0013] According to the present invention, the following effects are achieved. In other words, according to the temperature sensor of the present invention, the metal plate has a protrusion that protrudes upward and contacts at least the side of the thermal element portion when sealed in the resin sealing portion, thereby providing an anchor effect that prevents the resin sealing portion from peeling off and coming loose, as well as high thermal conductivity and suppression of misalignment of the thermal element portion. Therefore, the temperature sensor of the present invention can obtain high heat conductivity due to the protrusion and a stable adhesive state of the resin sealing portion, thereby achieving high-precision temperature measurement and high durability. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a perspective view showing a temperature sensor in a first embodiment of the temperature sensor according to the present invention, in which a resin sealing portion is indicated by a two-dot chain line. [Figure 2] 1A and 1B are a plan view and a side view, respectively, showing a temperature sensor in the first embodiment, in which a resin sealing portion is indicated by a two-dot chain line. [Figure 3] FIG. 10 is a perspective view showing a temperature sensor according to a second embodiment of the present invention, in which a resin sealing portion is indicated by a two-dot chain line. [Figure 4] 10A and 10B are a plan view and a side view showing a temperature sensor in a second embodiment, in which a resin sealing portion is indicated by a two-dot chain line. [Figure 5] FIG. 10 is a perspective view showing a temperature sensor according to a third embodiment of the present invention, in which a resin sealing portion is indicated by a two-dot chain line. [Figure 6] 10A and 10B are a plan view and a side view showing a temperature sensor in a third embodiment, in which a resin sealing portion is indicated by a two-dot chain line. DETAILED DESCRIPTION OF THE INVENTION

[0015] A first embodiment of a temperature sensor according to the present invention will be described below with reference to Figures 1 and 2. Note that in some of the drawings used in the following description, the scale has been appropriately changed as necessary to make each part recognizable or easily recognizable.

[0016] As shown in Figures 1 and 2, the temperature sensor 1 of this embodiment comprises a thermal element portion 2, a pair of lead terminals 3 connected to the thermal element portion 2, a metal plate 4 on whose upper surface the thermal element portion 2 is installed, and a resin sealing portion 5 that seals the thermal element portion 2 with resin on the metal plate 4. The metal plate 4 has a protruding portion 4a that contacts at least the side surface of the heat-sensitive element portion 2 and protrudes upward when sealed in the resin sealing portion 5.

[0017] The protruding portion 4a of this embodiment is formed to cover the side surface to the top surface of the heat-sensitive element portion 2 and has a U-shaped cross section. The protrusion 4a is formed by bending a strip-shaped portion of the metal plate 4 with two cuts.

[0018] That is, the protrusion 4a has a curved portion 4b that is formed by curving from the upper surface of the metal plate 4 along the outer peripheral surface of the thermal element portion 2, covering from the side to the upper surface of the thermal element portion 2, and a parallel portion 4c that protrudes from the curved portion 4b parallel to the upper surface of the metal plate 4. The metal plate 4 also has an opening 4e formed when the protruding portion 4a is bent, that is, an opening 4e cut in a strip shape from the edge 4f toward the heat-sensitive element portion 2.

[0019] The metal plate 4 has mounting holes 4d through which screws can be inserted so that the metal plate 4 can be fixed to an object to be measured with screws. The mounting hole 4d is formed in a circular shape in a portion where the resin sealing portion 5 is not molded. Furthermore, when the metal plate 4 is attached to the object to be measured with a screw inserted through the mounting hole 4d, the bottom surface of the metal plate 4 is exposed and not covered with the resin sealing portion 5 so that the bottom surface of the metal plate 4 is in close contact with the object to be measured.

[0020] The heat-sensitive element portion 2 is, for example, a chip thermistor molded into a cylindrical shape by glass molding. Furthermore, one end of a pair of lead terminals 3 is connected to the chip thermistor with a solder material. The pair of lead terminals 3 project in opposite directions from both ends of the heat-sensitive element portion 2, are bent at a right angle, and extend linearly and parallel to each other on both sides of the opening 4e.

[0021] The metal plate 4 is a crimp terminal made of a copper plate or the like and functions as a heat guide plate for the heat sensitive element portion 2 . The resin sealing portion 5 is formed by, for example, forming an epoxy resin or the like into a plate or cube shape on the metal plate 4 by transfer molding. The resin of the resin sealing portion 5 is also filled into the open portion of the U-shaped cross-section protruding portion 4a (inside the protruding portion 4a) during transfer molding, thereby sealing the heat-sensitive element portion 2.

[0022] In this way, in the temperature sensor 1 of this embodiment, the metal plate 4 has a protrusion 4a that protrudes upward and contacts at least the side surface of the thermal element portion 2 while sealed in the resin sealing portion 5.Since the protrusion 4a protrudes and is sealed within the resin sealing portion 5, an anti-peeling and anti-detachment effect (anchor effect) of the resin sealing portion 5 can be obtained.

[0023] Furthermore, compared to the conventional technology in which the contact between the thermal element portion 2 and the metal plate 4 is only at the bottom surface of the thermal element portion 2, the temperature sensor 1 of this embodiment can transfer heat from the protrusion 4a to at least the side surface of the thermal element portion 2, and the positioning effect of the protrusion 4a can suppress misalignment of the thermal element portion 2 during resin sealing.

[0024] Furthermore, the protrusion 4a is formed with a U-shaped cross section, covering the sides and top of the thermal element portion 2, so that heat can be transferred from the protrusion 4a not only to the sides but also to the top of the thermal element portion 2, and resin is filled into the open portion of the protrusion 4a, thereby achieving a higher anti-slip effect (anchor effect).

[0025] Next, second and third embodiments of the temperature sensor according to the present invention will be described below with reference to Figures 3 to 6. In the following description of each embodiment, the same components as those described in the above embodiments will be denoted by the same reference numerals, and the description thereof will be omitted.

[0026] The difference between the second embodiment and the first embodiment is that in the first embodiment, a pair of lead terminals 3 extend on both sides of the opening 4e (directly above the metal plate 4), whereas in the temperature sensor 21 of the second embodiment, a pair of lead terminals 23 extend parallel to each other and in a straight line directly above the opening 4e, as shown in Figures 3 and 4.

[0027] That is, the pair of lead terminals 23 in the second embodiment extend parallel to each other and in a straight line directly above the opening 4e via the U-shaped portion 23 that protrudes in opposite directions from both ends of the thermal element portion 2 and is then bent into a U-shape. The pair of lead terminals 23 are arranged directly above the opening 4e with a narrower gap between them than in the first embodiment via the U-shaped portion 23a. Therefore, the pair of lead terminals 23 extend in a manner that avoids being directly above the metal plate 4 except for the U-shaped portion 23a. In this way, in the temperature sensor 21 of the second embodiment, at least a portion of the pair of lead terminals 23 extends directly above the opening 4e, thereby preventing heat from being transferred from the metal plate 4 to the lead terminals 23 and being released to the outside.

[0028] Next, the difference between the third embodiment and the first embodiment is that in the first embodiment, the protrusion 4a is formed in a U-shaped cross section and has a curved portion 4b and a parallel portion 4c, whereas in the temperature sensor 31 of the third embodiment, as shown in Figures 5 and 6, the protrusion 44a is composed only of a portion that protrudes vertically upward from the top surface of the metal plate 4 and has a pair of recessed portions 44b.

[0029] That is, the protruding portion 44a of the third embodiment has a pair of recessed portions 44b cut out in a rectangular shape on both side portions, and the resin of the resin sealing portion 5 is filled into the pair of recessed portions 44b. In this way, in the temperature sensor 31 of the third embodiment, the protrusion 44a has a recessed portion 44b, and the resin of the resin sealing portion 5 is filled up to the recessed portion 44b, thereby achieving an even higher anti-detachment effect.

[0030] The technical scope of the present invention is not limited to the above-described embodiments and examples, and various modifications can be made without departing from the spirit of the present invention. For example, although the protrusion in the third embodiment has a recess, the protrusion in the first and second embodiments may also have a recess. [Explanation of symbols]

[0031] 1, 21, 31... temperature sensor, 2... heat-sensitive element portion, 3, 23... lead terminal, 4... metal plate, 4a, 44a... protruding portion, 5... resin sealing portion, 4e... opening, 44b... recessed portion

Claims

1. a heat-sensitive element portion; a pair of lead terminals connected to the heat-sensitive element portion; a metal plate having the heat-sensitive element portion disposed on an upper surface thereof; a resin sealing portion that seals the heat-sensitive element portion with resin on the metal plate, The temperature sensor is characterized in that the metal plate has a protrusion that protrudes upward and contacts at least a side surface of the heat-sensitive element portion when sealed in the resin sealing portion.

2. 2. The temperature sensor according to claim 1, The temperature sensor is characterized in that the protrusion is formed in a U-shaped cross section and covers the side surface and upper surface of the heat-sensitive element portion.

3. 2. The temperature sensor according to claim 1, the metal plate has an opening cut in a strip shape from an edge toward the heat-sensitive element portion, A temperature sensor characterized in that at least a portion of the pair of lead terminals extends directly above the opening.

4. 4. The temperature sensor according to claim 3, the protrusion is formed by bending a band-shaped portion of the metal plate with two cuts, The temperature sensor is characterized in that the opening is a portion that is opened in the metal plate when the protrusion is formed by the bending process.

5. 2. The temperature sensor according to claim 1, the protrusion comprises a recess; A temperature sensor characterized in that the resin of the resin sealing portion is filled up to the recessed portion.

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