JP7421425B2 - thermal power generation device - Google Patents

Description

The present invention relates to a thermal power generation device and a method for manufacturing the same.

Patent Document 1 discloses a thermoelectric generator including a thermoelectric generator that converts thermal energy into electric power. This thermoelectric power generation device consists of a fixed part, a heat conductive member connected to the heat input surface of the thermoelectric power generating element and the fixed part, a heat dissipating member such as a heat sink connected to the heat dissipating surface of the thermoelectric generating element, and a thermoelectric generator. A cover that covers electronic components such as elements. The cover is formed of a heat insulating material such as plastic in order to prevent the heat conducted through the fixed portion from being conducted to the heat radiation surface of the thermoelectric generating element through the heat radiation member.

Unexamined Japanese Patent Publication No. 2014-8569

In the thermoelectric power generation device of Patent Document 1, a fixed part and a heat radiating member are connected by a cover, and a thermoelectric generating element is sandwiched between the heat conductive member and the heat radiating member attached to the fixed part inside the cover.

Generally, dimensional errors occur in each component such as a fixing part, a heat radiation member, a cover, and a heat conduction member that constitute such a thermal power generation device. Furthermore, since differences in thermal conductivity occur depending on the material of each component, the amount of dimensional change in each component due to changes in ambient temperature also differs from each other.

In this way, deviations in dimensions from the design values occur in each component, resulting in gaps between the thermoelectric generation element and the heat conduction member or the heat radiation member, or conversely, the generation of heat by the heat conduction member and the heat radiation member. There is a risk that the element may be compressed. If a gap occurs between the thermoelectric generating element and the heat conductive member, heat will not be sufficiently conducted to the thermoelectric generating element, and power generation efficiency will decrease. Furthermore, if the thermoelectric generating element is compressed, there is a risk that the thermoelectric generating element may be damaged.

The present invention has been made in view of the above problems, and aims to improve the power generation efficiency and durability of a thermal power generation device.

The present invention is a thermoelectric power generation device that includes a case and a thermoelectric conversion element that is housed in the case and generates an electromotive force according to a temperature difference between a heat absorption surface and a heat radiation surface, and the case is configured to absorb heat of the thermoelectric conversion element. a first member that is thermally connected to the surface, a second member that is thermally connected to the heat dissipation surface of the thermoelectric conversion element, and a first member that is provided between the first and second members; the thermoelectric conversion element is attached to the first member or the second member with an elastic adhesive , and one end is attached to the first member and the second member. a thermoelectric conversion element is attached to one end of the case with an elastic adhesive, a thermal conductive member is provided between the other end and the other of the first member and the second member to support the thermoelectric conversion element; The member is characterized in that a groove portion into which the heat conductive member is inserted is formed on the inner periphery of the member .

In this invention, since the thermoelectric conversion element is attached to the first member or the second member using an elastic adhesive having elasticity, dimensional errors or dimensional changes due to temperature changes occur in the first member, the second member, and the case member. However, dimensional errors and dimensional changes can be absorbed by the elasticity of the elastic adhesive. Thereby, it is possible to suppress the generation of a gap between the thermoelectric conversion element and the first member or the second member, and the compression of the thermoelectric conversion element by the first member and the second member. Moreover, in this invention, by applying an elastic adhesive to the tip of the heat conductive member in a state where the first member or the second member to which the heat conductive member is attached and the case member are assembled, the tip of the heat conductive member is The space between the groove and the groove functions as a pocket. Therefore, the elastic adhesive is stored at the tip of the heat conductive member, and dripping from the tip is suppressed. As a result, it is possible to improve the adhesion state of the thermoelectric conversion element to the tip of the heat conduction member, and to absorb compressive force and tensile force to the thermoelectric conversion element, and to transfer the compressive force and tensile force from the thermoelectric conversion element to the first member or the heat conduction member. Heat conduction to the second member can be performed effectively.

Further, the present invention provides a first threaded member provided on one of the first member and the second member in which a female thread is formed, and the other of the first member and the second member is inserted and screwed into the female thread of the first threaded portion. a second threaded member formed with a male thread, the first threaded member and the other of the first and second members through which the second threaded member is inserted are spaced apart without contacting each other. It is characterized by

In this invention, since the first screw member does not contact the other of the first member and the second member, the positional relationship between the first member and the second member is determined by the heat insulating member. In other words, even if the dimensions of the first screw member vary, the first screw member does not come into contact with the other of the first member and the second member. does not interfere with positioning. Thereby, the first member and the second member are appropriately positioned by the heat insulating member, and the thermoelectric conversion element and the first member and the second member due to the first screw member contacting the other of the first member and the second member are Generation of a gap between the two members is prevented. Therefore, thermal conductivity from the thermoelectric conversion element to the other of the first member and the second member is ensured.

Further, in the present invention, a mounting hole is formed in one of the first member and the second member to which the heat conductive member is attached, and a mounting hole is formed in which one end of the heat conductive member is accommodated, and the heat conductive member is attached to the first member in the mounting hole. An elastic member biased toward the other of the first member and the second member is provided, and the heat conductive member is attached to one of the first member and the second member by an elastic adhesive filled in the attachment hole together with the elastic member. It is characterized by

In this invention, the heat conductive member and the thermoelectric conversion element are elastically supported by the elastic member in addition to the elastic adhesive. As a result, the elastic force that supports the thermoelectric conversion element becomes the resultant force of the elastic force caused by the elastic adhesive and the coil spring. By providing the elastic member in this way, the elastic force that supports the thermoelectric conversion element can be adjusted.

According to the present invention, the power generation efficiency and durability of the thermal power generation device are improved.

1 is a partial cross-sectional view of a hydraulic cylinder to which a thermoelectric generator according to an embodiment of the present invention is attached. 1 is a partially enlarged sectional view of a hydraulic cylinder to which a thermoelectric generator according to an embodiment of the present invention is attached. FIG. 2 is a plan view of a heat dissipation member of a thermoelectric power generation device according to an embodiment of the present invention. FIG. 2 is a plan view of a case member of a thermoelectric power generation device according to an embodiment of the present invention. FIG. 2 is a cross-sectional view for explaining a method of manufacturing a thermoelectric power generation device according to an embodiment of the present invention, and is a diagram showing a state in which a heat radiating member and a case member are assembled. FIG. 7 is a partially enlarged sectional view showing a modification of the thermal power generation device according to the embodiment of the present invention.

Hereinafter, a thermal power generation device 100 according to an embodiment of the present invention will be described with reference to the drawings.

The thermal power generation device 100 is used, for example, as a power source for a sensor device 101 provided in a fluid pressure system of a construction machine (such as a hydraulic excavator).

First, with reference to FIG. 1, a sensor device 101 to which a thermoelectric power generation device 100 is applied will be described.

In the following description, the sensor device 101 is an oil leak sensor that detects a leak of hydraulic oil occurring in a hydraulic cylinder 1 (hydraulic cylinder) of a fluid pressure system that drives drive objects (not shown) such as a boom, an arm, and a bucket. Explain the case.

As shown in FIG. 1, the hydraulic cylinder 1 includes a cylindrical cylinder tube 2, a piston rod 3 inserted into the cylinder tube 2, and a piston 4 provided at the base end of the piston rod 3. The piston 4 is provided slidably along the inner peripheral surface of the cylinder tube 2. The interior of the cylinder tube 2 is divided by the piston 4 into a rod side chamber 2a and an anti-rod side chamber 2b.

The tip of the piston rod 3 extends from the open end of the cylinder tube 2. When hydraulic oil is selectively introduced into the rod side chamber 2a or the anti-rod side chamber 2b from a hydraulic power source (not shown), the piston rod 3 moves relative to the cylinder tube 2. This causes the hydraulic cylinder 1 to expand and contract.

A cylinder head 5 through which a piston rod 3 is inserted is provided at the open end of the cylinder tube 2 . The cylinder head 5 is fastened to the open end of the cylinder tube 2 using a plurality of bolts 6.

As shown in FIG. 2, the cylinder head 5 has an annular gap (hereinafter referred to as an "annular gap 8") between the outer circumferential surface of the piston rod 3 and the inner circumferential surface of the cylinder head 5 that is sealed. A rod seal 7a, a detection seal 7b that seals an annular gap 8 and partitions a detection space 9 together with the rod seal 7a, a bush 7c that slidably supports the piston rod 3, and is attached to the outer peripheral surface of the piston rod 3. A dust seal 7d is provided to scrape out the dust and prevent dust from entering into the cylinder tube 2 from the outside.

The sensor device 101 is attached to the outer periphery of the cylinder head 5 of the hydraulic cylinder 1 and detects the pressure of hydraulic oil leaking from the annular gap 8 between the outer periphery of the piston rod 3 and the inner periphery of the cylinder head 5. . The detection results of the sensor device 101 are transmitted to the controller 102 by wireless communication. The controller 102 determines whether there is an oil leak in the hydraulic cylinder 1 based on the detection result of the sensor device 101.

The sensor device 101 includes a thermoelectric generator 100 that generates electricity based on the temperature difference between a housing 20 as a first member and a heat dissipation member 30 as a second member, and a thermoelectric generator 100 that generates electricity based on a temperature difference between a housing 20 as a first member and a heat dissipation member 30 as a second member. It includes a pressure sensor 80 as a sensor unit that detects oil pressure, and a circuit board 81 to which the thermoelectric generator 100 and the pressure sensor 80 are electrically connected through wirings 16 and 82, respectively. Mounted on the circuit board 81 are a power supply circuit that supplies power generated by the thermoelectric power generation device 100 to the pressure sensor 80 and a communication circuit that wirelessly transmits the detection results of the pressure sensor 80 to the controller 102.

The thermoelectric power generation device 100 includes a case 10 and a thermoelectric conversion element (hereinafter simply referred to as "thermoelectric element 15") that is housed in the case 10 and generates an electromotive force according to the temperature difference between a heat absorption surface 15a and a heat radiation surface 15b. , is provided.

The case 10 includes a housing 20 attached to the cylinder head 5 of the hydraulic cylinder 1, a heat radiating member 30 configured as a heat sink having a plurality of fins 31a on the outer periphery, and a thermoelectric element 15 sandwiched between the housing 20 and the heat radiating member 30. It has a spacer 40 as a resin-made heat insulating member surrounding the spacer.

The housing 20 is formed of the same ferrous material (more specifically, steel) as the cylinder head 5 of the hydraulic cylinder 1, and is attached to the cylinder head 5. Heat generated in the hydraulic cylinder 1 is transmitted to the housing 20 through the cylinder head 5.

The housing 20 includes an accommodation recess 21 that opens at the end face and accommodates the thermoelectric element 15, a sensor accommodation hole 22 that opens in the accommodation recess 21 and accommodates the pressure sensor 80, and a housing 20 that abuts against the cylinder head 5 of the hydraulic cylinder 1. A communication path 23 is formed that opens to the contact surface of the sensor housing hole 22 and to the sensor housing hole 22 . The communication passage 23 communicates with the detection space 9 through a head-side passage 9a formed in the cylinder head 5 of the hydraulic cylinder 1. As a result, the pressure of the hydraulic oil leaking into the detection space 9 through the annular gap 8 is guided to the sensor housing hole 22 through the head side passage 9a and the communication passage 23, and the pressure is detected by the pressure sensor 80.

A first heat conduction member 50 is attached to the housing 20 as a heat conduction member that transmits heat of the housing 20 to a heat absorption surface 15a of a thermoelectric element 15, which will be described later. The first heat conductive member 50 is a cylindrical rod-like member made of the same material as the housing 20 (steel in this embodiment), and one end is attached to the bottom of the housing 20 with a mounting bolt 70. The mounting bolt 70 is a stud bolt (fully threaded bolt) with threaded portions formed at both ends, and both ends are female threaded at the bottom of the accommodation recess 21 and one end surface of the first thermally conductive member 50, respectively. Screw together. The thermoelectric element 15 is attached to the other end (tip) of the first heat conductive member 50.

The heat dissipation member 30 is made of a material with excellent thermal conductivity, such as an aluminum-based or copper-based material. Therefore, the heat dissipating member 30 has better thermal conductivity than the housing 20.

The heat dissipation member 30 is formed into a bottomed cylindrical shape with one end configured as a closed end. A plurality of annular fins 31a are provided on the outer periphery of the heat dissipation member 30, lining up in the axial direction. A boss portion 32 that protrudes in the axial direction toward the outside of the heat radiating member 30 is provided at the bottom of the heat radiating member 30 .

As shown in FIGS. 2 and 3, a slit 32b through which the circuit board 81 is inserted is formed at the bottom of the heat dissipation member 30. A portion of the circuit board 81 protrudes from an accommodation space S1 inside the housing 20 and the spacer 40, which will be described later, into the inner space S2 of the heat dissipation member 30 through the slit 32b. Note that FIG. 3 is a plan view of the heat radiating member 30 viewed from the direction of arrow A in FIG.

The inner space S2 of the heat radiating member 30 is potted and sealed with a mold resin 35 together with a part of the circuit board 81 and the head of a resin screw 72 which will be described later. In this way, the circuit board 81 is not entirely housed inside the metal housing 20 or the heat dissipation member 30, but a part of it is housed outside the accommodation space S1 inside the housing 20, specifically, inside the heat dissipation member 30. It protrudes into the inner space S2 of the heat dissipation member 30 facing (exposed) to the outside of the power generation device 100. Thereby, wireless communication by the communication means provided on the circuit board 81 can be performed stably. Note that the inner space S2 of the heat dissipation member 30 is sealed with a molded resin 35, but resin is less likely to interfere with communication radio waves than metal, so even if it is sealed with the molded resin 35, it is not sufficient for wireless communication. can be stabilized. Note that the mold resin 35 is not an essential component, and the inner space S2 does not need to be potted.

A second heat conductive member 51 is attached to the heat dissipation member 30 as a heat conduction member that transfers heat from a heat dissipation surface 15b of the thermoelectric element 15 to the heat dissipation member 30, which will be described later. The second heat conductive member 51 is a cylindrical rod-shaped member made of the same material as the heat radiating member 30 and having approximately the same diameter as the first heat conductive member 50. A mounting bolt 71 is inserted into one end of the second heat conductive member 51, and the second heat conductive member 51 is attached to the distal end surface 32a of the boss portion 32 of the heat dissipating member 30 by the mounting bolt 71. The mounting bolt 71 is inserted through the insertion hole 30a at the bottom of the heat dissipation member 30 and is screwed into a female thread provided at one end of the second heat conduction member 51. The thermoelectric element 15 is attached to the other end (tip) of the second heat conductive member 51 .

In this way, the thermoelectric element 15 is held between the first heat conductive member 50 attached to the housing 20 and the second heat conductive member 51 attached to the heat radiating member 30.

The spacer 40 is made of a resin material with high heat insulation properties. The spacer 40 has a through hole 40a along the central axis at its radial center, and is formed in a cylindrical shape so as to surround the thermoelectric element 15. The spacer 40 is sandwiched between the housing 20 and the heat radiating member 30. The spacer 40 includes a main body portion 41 having a tapered outer circumferential surface, and an insertion portion 42 inserted into the accommodation recess 21 of the housing 20 .

The insertion portion 42 is formed to protrude in the axial direction from the end of the main body portion 41 toward the housing 20 . The outer diameter of the insertion portion 42 is smaller than the outer diameter of the end of the main body 41 (minimum outer diameter of the main body 41), and the stepped surface formed by the difference in outer diameter between the insertion portion 42 and the main body 41 comes into contact with the end surface of the housing 20. The outer periphery of the main body portion 41 is formed in a tapered shape such that the outer diameter increases as it moves away from the housing 20 along the axial direction of the spacer 40, in other words, as it moves from the housing 20 toward the heat radiating member 30.

The accommodation recess 21 of the housing 20 and the through hole 40a of the spacer 40 form an accommodation space S1 in which the thermoelectric element 15 is accommodated. As shown in FIG. 4, a slit 40b extending in the axial direction is formed in the inner peripheral surface of the spacer 40, into which both edges of the circuit board 81 are inserted and which supports the circuit board 81. Note that FIG. 4 is a plan view of the spacer 40 viewed from the direction of arrow A in FIG. Further, in FIG. 4, the circuit board 81 is schematically shown by a two-dot chain line.

Furthermore, an accommodation groove 40c is formed in the inner circumferential surface of the through hole 40a of the spacer 40 and extends in the axial direction as a groove portion into which the first heat conductive member 50 and the second heat conductive member 51 are inserted. The housing groove 40c is a groove having a substantially semicircular cross section that matches the outer shapes of the first heat conductive member 50 and the second heat conductive member 51. Moreover, the housing groove 40c, the first heat conductive member 50, and the second heat conductive member 51 are provided at positions shifted from the center of the housing recess 21 of the housing 20 (see FIGS. 2 and 4). The housing groove 40c functions to align the first heat conductive member 50 and the second heat conductive member 51 in the circumferential direction when the thermoelectric generator 100 and the sensor device 101 are assembled.

As shown in FIG. 2, the boss portion 32 of the heat radiating member 30 is inserted into the through hole 40a of the spacer 40 from the side opposite to the housing 20. As a result, one opening of the through hole 40a of the spacer 40 is closed by the heat radiating member 30. In other words, the housing space S1 formed by the housing recess 21 of the housing 20 and the through hole 40a of the spacer 40 is closed by the heat radiating member 30.

The housing 20 and the heat radiating member 30 are connected via a spacer 40, and do not come into direct contact with each other. Therefore, heat conduction between the housing 20 and the heat radiating member 30 is suppressed by the spacer 40. In this way, the spacer 40 not only functions as a spacer that prevents the housing 20 and the heat radiating member 30 from coming into direct contact, but also functions as a heat insulating member that suppresses heat conduction between the housing 20 and the heat radiating member 30. Furthermore, the spacer 40 is provided so as to surround the thermoelectric element 15 , and together with the housing 20 forms an accommodation space S<b>1 in which the thermoelectric element 15 is accommodated. Thereby, the spacer 40 suppresses temperature changes in the housing space S1 due to the influence of outside air, specifically, temperature changes in the first heat conductive member 50 and the second heat conductive member 51.

The housing 20 and the heat dissipation member 30 also include a connection member 52 as a first threaded member provided in the housing 20 and having a female thread formed at its tip, and a male screw threaded through the heat dissipation member 30 and screwed into the female thread of the connection member 52. They are connected to each other by a resin screw 72 as a second screw member made of resin. That is, the housing 20 and the connecting member 52 are connected via the spacer 40 and are also connected by the connecting member 52 and the resin screw 72.

The connecting member 52 is a cylindrical member, and one end is attached to the bottom of the housing recess 21 of the housing 20 . Like the first heat conductive member 50, the connecting member 52 is attached to the housing 20 by a mounting bolt 73 such as a stud bolt that screws into both the bottom of the accommodation recess 21 and the connecting member 52. The other end of the connecting member 52 is spaced apart from the distal end surface 32a of the boss portion 32 of the heat dissipating member 30 without contacting it. That is, in the axial direction of the connecting member 52, a gap is formed between the tip of the connecting member 52 and the heat radiating member 30, and the connecting member 52 and the heat radiating member 30 are configured not to come into contact with each other. Although detailed illustrations are omitted, three connecting members 52 are attached to the housing 20 in this embodiment.

The resin screw 72 is made of a resin material with excellent heat insulation properties. The resin screw 72 is inserted through the insertion hole 32c formed in the bottom (boss portion 32) of the heat dissipation member 30 and screwed into the connection member 52. Three insertion holes 32c are formed at the bottom of the heat dissipation member 30 corresponding to the connection members 52 (see FIG. 3). By tightening the resin screws 72 with a predetermined tightening force, the housing 20 and the heat dissipation member 30 are screwed together. It is concluded. Note that even when the resin screw 72 is tightened with a predetermined tightening force, a gap exists between the connecting member 52 and the bottom of the heat radiating member 30.

The thermoelectric element 15 is a Seebeck element that has a heat absorption surface 15a and a heat radiation surface 15b, which are a pair of parallel planes, and generates an electromotive force due to a temperature difference between the heat absorption surface 15a and the heat radiation surface 15b. In the thermoelectric element 15, the heat absorption surface 15a is bonded to the distal end surface of the first heat conduction member 50 by the first adhesive 55, and the heat dissipation surface 15b is bonded to the second heat conduction member 51 by the second adhesive 56. In this way, the heat absorbing surface 15a is thermally connected to the housing 20 through the first adhesive 55 and the first heat conductive member 50. Further, the heat radiation surface 15b is thermally connected to the heat radiation member 30 through the second adhesive 56 and the second heat conductive member 51. The thermoelectric element 15 absorbs heat with its heat absorption surface 15a and radiates heat from its heat radiation surface 15b, thereby generating a temperature difference inside and generating an electromotive force. That is, the thermoelectric element 15 detects the difference between the temperature of the housing 20 that is transmitted to the heat absorption surface 15a through the first heat conduction member 50 and the temperature of the heat radiation member 30 that is transmitted to the heat radiation surface 15b through the second heat conduction member 51. Generates an electromotive force according to the The electromotive force of the thermoelectric element 15 is supplied to the circuit board 81 connected through the wiring 16.

The first adhesive 55 is a thermally conductive adhesive with excellent thermal conductivity (hereinafter, the first adhesive 55 is also referred to as the "thermal conductive adhesive 55"). It is desirable that the thermally conductive adhesive 55 has better thermal conductivity than the elastic adhesive 56 (second adhesive). As the first adhesive 55, for example, an adhesive formed by adding a metal or ceramic with high thermal conductivity as a filler to a silicon-based or epoxy-based base material is used.

The second adhesive 56 is an elastic adhesive 56 that is elastic in a hardened state (hereinafter, the second adhesive 56 is also referred to as the "elastic adhesive 56"). The elastic adhesive 56 in this embodiment is, for example, a silicone adhesive or a rubber adhesive that is liquid before hardening and exhibits elasticity when hardened. Furthermore, the elastic adhesive 56 is not limited to an adhesive that is in a liquid (gel) state before curing, but may be a sheet-like adhesive member such as an acrylic double-sided tape, for example. As the elastic adhesive material 56, it is desirable to use a material having elasticity and excellent thermal conductivity. Note that the first adhesive material 55 may also be a liquid adhesive before curing, or may be a sheet-like (tape-like) adhesive member.

In this embodiment, the "adhesive" refers to an adhesive that is in a liquid state before curing, as well as a solid adhesive and a sheet-like material formed by impregnating or applying an adhesive to a base member. This also includes adhesive members and the like. That is, the "adhesive" in this embodiment is not limited to liquid adhesive.

As described above, in the thermoelectric power generation device 100, the heat generated in the hydraulic cylinder 1 is absorbed from the housing 20 to the heat absorption surface 15a of the thermoelectric element 15 through the first heat conduction member 50 and the heat conductive adhesive 55. The heat absorbed by the heat absorption surface 15a of the thermoelectric element 15 is radiated from the heat radiation surface 15b through the elastic adhesive 56, the second heat conductive member 51, and the heat radiation member 30, and thereby the thermoelectric element 15 generates electricity. The electric power generated by the thermoelectric element 15 of the thermoelectric power generation device 100 is supplied to the circuit board 81, and the pressure sensor 80 and the communication circuit are driven. In this way, the sensor device 101 is equipped with the thermoelectric power generation device 100 that generates electricity using the heat generated in the hydraulic cylinder 1 that is the object of sensing, so that the sensor device 101 can be driven independently without receiving power from an external source. Can be done. Therefore, there is no need to route wiring for feeding power to the sensor device 101 around the sensor device 101 and the hydraulic cylinder 1, and the sensor device 101 can be easily attached.

Here, dimensional errors may occur in each component such as a housing, a heat radiating member, a case member, a first heat conductive member, and a second heat conductive member that constitute the thermoelectric power generation device. Therefore, when the thermoelectric power generation device is assembled, the distance between the first heat conductive member and the second heat conductive member may differ from the designed value. As a result, the thermoelectric element is compressed by the first heat-conducting member and the second heat-conducting member in a direction perpendicular to the heat-absorbing surface and the heat-radiating surface, and vice versa. There is a risk that the thermoelectric element may be pulled. Further, each component is made of a different material, and the case member in particular is made of a resin material with low thermal conductivity. Since each component has a different amount of dimensional change due to temperature change, the distance between the first heat conductive member and the second heat conductive member changes depending on the temperature change, and thermal stress in the compressive or tensile direction is applied to the thermoelectric element. arise. If a compressive force is applied to the thermoelectric element in this way, the thermoelectric element may be damaged, and if a tensile force is applied to the thermoelectric element, a gap will be created between the thermoelectric element and the first heat conductive member or the second heat conductive member. This may cause loss in heat conduction.

In contrast, in the present embodiment, the thermoelectric element 15 is bonded to the second heat conductive member 51 using an elastic adhesive 56 that has elasticity in a hardened state, so that dimensional errors occur in each component of the thermoelectric generator 100. The elasticity of the elastic adhesive 56 can absorb the difference in the amount of dimensional change due to temperature change. In other words, the elasticity of the elastic adhesive 56 can absorb compressive and tensile forces on the thermoelectric element 15 caused by dimensional errors and thermal stress. Therefore, it is possible to prevent excessive compressive force and tensile force from acting on the thermoelectric element 15, thereby reducing heat conduction loss between the first heat conductive member 50 and the second heat conductive member 51 and the thermoelectric element 15. At the same time, the durability of the thermoelectric element 15 can be improved.

Next, a method for manufacturing the sensor device 101 will be described.

In this embodiment, the sensor device 101 is manufactured by assembling the heat radiating member 30, the spacer 40, the thermoelectric element 15, the circuit board 81, and the pressure sensor 80, and attaching this assembly to the housing 20. This will be explained in detail below.

First, the second heat conductive member 51 is attached to the heat radiating member 30 using the attaching bolts 71.

Next, the heat radiation member 30 and the spacer 40 are assembled. Specifically, while inserting the second heat conductive member 51 into the accommodation groove 40c on the inner periphery of the spacer 40, the boss portion 32 of the heat radiating member 30 is inserted into the through hole 40a of the spacer 40, and the heat radiating member 30 and the spacer 40 are connected to each other. be attached using an adhesive.

Next, the pressure sensor 80 and the thermoelectric element 15 are connected to the circuit board 81 by the wirings 16 and 82. Furthermore, the circuit board 81 is inserted from the opening of the spacer 40 into the slit 40b (see FIG. 4) on the inner peripheral surface, and is passed through the slit 32b (see FIG. 3) formed in the boss portion 32 of the heat dissipation member 30 to partially is made to protrude into the inner space S2 of the heat radiating member 30. In this way, an assembly including the heat dissipating member 30 is constructed.

Next, an elastic adhesive 56 is applied to the tip of the second heat conductive member 51. At this time, for example, as shown in FIG. 5, the central axis of the heat dissipating member 30 extends substantially horizontally, and the second heat conductive member 51 attached to the heat dissipating member 30 extends vertically below the central axis of the heat dissipating member 30. The elastic adhesive 56 is applied to the tip of the second heat conductive member 51 in such a posture that the second heat conductive member 51 is positioned in the same position. In FIG. 5, the lower side of the figure shows the downward direction in the vertical direction, and the left-right direction shows the horizontal direction. By doing so, the space C formed by the tip of the second thermally conductive member 51 and the housing groove 40c on the inner circumference of the spacer 40 functions as a pocket for storing the elastic adhesive 56, so that the second thermally conductive member The elastic adhesive material 56 can be prevented from dripping from the tip of the member 51. Then, the thermoelectric element 15 is pressed against the elastic adhesive 56 attached to the tip of the second thermally conductive member 51 in this manner, and the elastic adhesive 56 is cured after a predetermined period of time. Thereby, the thermoelectric element 15 is attached to the tip of the second heat conductive member 51.

Next, the first heat conductive member 50 is attached to the bottom of the housing 20 using the mounting bolts 70, and the connecting member 52 is attached to the bottom of the housing 20 using the mounting bolts 73.

Next, the assembly including the heat radiating member 30 and the housing 20 are assembled. Specifically, first, the thermally conductive adhesive 55 is attached to the tip of the first thermally conductive member 50 . Then, the spacer 40 is inserted into the housing recess 21 of the housing 20 so that the first heat conductive member 50 and the housing groove 40c (see FIGS. 4 and 5) on the inner circumference of the spacer 40 are aligned. Furthermore, the thermoelectric element 15 attached to the tip of the second thermally conductive member 51 is pressed against the thermally conductive adhesive 55 attached to the tip of the first thermally conductive member 50, and the thermoelectric element 15 is attached to the tip of the first thermally conductive member 50. The element 15 is bonded. Further, as the spacer 40 is inserted into the housing recess 21 of the housing 20, the pressure sensor 80 is housed in the sensor housing hole 22 at the bottom of the housing 20 and attached to the housing 20. Further, an adhesive is also applied between the spacer 40 and the housing 20 to fix them together.

Next, the resin screw 72 is inserted into the insertion hole 32c of the boss portion 32 from inside the heat dissipation member 30, and is screwed together with the connecting member 52 and fastened with a predetermined tightening force. Then, the inner space S2 of the heat radiating member 30 is filled with mold resin 35.

Through the above steps, the assembly of the sensor device 101 shown in FIG. 2 is completed.

The assembly of the sensor device 101 is not limited to the order described above, and the order may be changed as much as possible. Moreover, each step may be performed simultaneously as much as possible. Note that, for example, the thermoelectric element 15 and the pressure sensor 80 are connected to the circuit board 81 with the thermoelectric element 15 bonded to the first heat conductive member 50 of the housing 20 and the pressure sensor 80 attached to the housing 20 by wiring. Work becomes complicated. Therefore, in order to efficiently assemble the sensor device 101, the thermoelectric element 15, the pressure sensor 80, and the circuit board 81 are connected in advance to form an assembly as described above, and the assembly is assembled using the heat dissipating member 30 (and the spacer). 40) is desirable.

According to the above embodiment, the following effects are achieved.

In the thermoelectric power generation device 100, the thermoelectric element 15 is bonded to the second heat conductive member 51 using an elastic adhesive 56. Therefore, compressive force and tensile force on the thermoelectric element 15 caused by thermal stress due to dimensional errors and differences in thermal conductivity of each component of the thermoelectric generator 100 can be absorbed by the elasticity of the elastic adhesive 56. As a result, a gap is created between the first heat conductive member 50 or the second heat conductive member 51 and the thermoelectric element 15 due to the tensile force, and the gap causes loss of heat conduction, or the thermoelectric element 15 is damaged due to the compressive force. You can refrain from doing things. Therefore, the power generation efficiency and durability of the thermal power generation device 100 can be improved.

In addition, in the thermoelectric power generation device 100, since the second adhesive material 56 to which the thermoelectric element 15 is attached exhibits elasticity, an elastic member other than the adhesive material is provided and the thermoelectric element 15 is elastically supported by the elastic member. The configuration of the thermal power generation device 100 can be made compact compared to the above.

Further, the thermoelectric element 15 is bonded to the second heat conductive member 51 with an elastic adhesive 56 and is bonded to the first heat conductive member 50 with a heat conductive adhesive 55 having better thermal conductivity than the elastic adhesive 56. be done. Thereby, compressive force and tensile force acting on the thermoelectric element 15 can be absorbed by the elastic adhesive 56, and heat conduction from the housing 20 to the thermoelectric element 15 can be improved. Therefore, it is possible to more appropriately ensure the power generation efficiency and durability of the thermal power generation device 100.

In addition, the housing 20 and the heat dissipation member 30 are not connected by directly screwing the housing 20 and the heat dissipation member 30 together, but by using a resin screw 72 that is inserted between the connecting member 52 attached to the housing 20 and the heat dissipation member 30. and are screwed together. Thereby, the housing 20 and the heat dissipation member 30 can be assembled without relative rotation, so that the first heat conduction member 50 attached to the housing 20 and the second heat conduction member 51 attached to the heat dissipation member 30 can be assembled together. Positioning becomes easy. Therefore, the ease of assembling the thermoelectric power generation device 100 can be improved.

Moreover, in the state where the housing 20 and the heat radiating member 30 are assembled, the connecting member 52 and the heat radiating member 30 are separated from each other without contacting each other. Therefore, the positional relationship between the housing 20 and the heat radiating member 30 is determined by the spacer 40. That is, even if the dimensions of the connecting member 52 vary, the connecting member 52 does not come into contact with the heat radiating member 30, so the connecting member 52 does not interfere with the positioning of the housing 20 and the heat radiating member 30 by the spacer 40. Therefore, the housing 20 and the heat radiating member 30 are properly positioned by the spacer 40. This can prevent the generation of a gap between the thermoelectric element 15 and the heat radiating member 30 (second heat conductive member 51 in this embodiment) due to contact between the connecting member 52 and the heat radiating member 30. Therefore, thermal conductivity from the thermoelectric element 15 to the heat radiation member 30 is ensured, and the power generation efficiency of the thermoelectric power generation device 100 can be improved.

Furthermore, an accommodation groove 40c into which the first heat conductive member 50 and the second heat conductive member 51 are inserted is formed in the inner peripheral surface of the spacer 40. Thereby, the alignment between the first heat conductive member 50 and the second heat conductive member 51 becomes even easier, and the ease of assembling the thermal power generation device 100 can be improved. Moreover, by applying the elastic adhesive 56 to the tip of the second heat conductive member 51 in a state where the heat dissipation member 30 to which the second heat conductive member 51 is attached and the spacer 40 are assembled, the second heat conductive member 51 Since the space C between the tip and the accommodation groove 40c functions as a pocket, the elastic adhesive 56 can be stored and dripping can be suppressed. As a result, it is possible to improve the adhesion state of the thermoelectric element 15 to the tip of the second heat conductive member 51, thereby absorbing compressive force and tensile force to the thermoelectric element 15, and dissipating heat from the thermoelectric element 15 to the heat dissipating member 30. conduction can be performed more effectively.

Next, a modification of this embodiment will be described. The following modified examples are also within the scope of the present invention, and it is also possible to combine the configuration shown in the modified example with the configuration described in the above embodiment, or to combine the configurations described in the following different modified examples. It is.

First, a modification shown in FIG. 6 will be described. In the modification shown in FIG. 6, the thermoelectric element 15 is bonded to both the first thermally conductive member 50 and the second thermally conductive member 51 using a thermally conductive adhesive 55. Furthermore, a mounting hole 24 into which an end portion of the first heat conductive member 50 is inserted is formed at the bottom of the housing 20 .

A coil spring 75 as an elastic member is accommodated in the attachment hole 24 in a compressed state by the end of the first heat conductive member 50 inserted into the attachment hole 24 and the bottom of the housing 20 . The coil spring 75 urges the first heat conductive member 50 along the axial direction of the first heat conductive member 50 toward the second heat conductive member 51 (heat radiating member 30). Further, the attachment hole 24 is filled with an elastic adhesive 56. First thermally conductive member 50 is attached to housing 20 by elastic adhesive 56 .

As a result, compressive force and tensile force on the thermoelectric element 15 caused by dimensional errors and thermal stress in each component of the thermoelectric generator 100 can be absorbed by the elastic adhesive 56 in the mounting hole 24 and the elasticity of the coil spring 75. . Therefore, even with such a modification, the same effects as those of the above embodiment can be achieved.

Further, in the modification shown in FIG. 6, the first heat conductive member 50 and the thermoelectric element 15 are elastically supported by the coil spring 75 in addition to the elastic adhesive 56, so that the elastic force supporting the thermoelectric element 15 is , which is the resultant force of the elastic forces of the elastic adhesive 56 and the coil spring 75. By providing the coil spring 75 in this manner, the elastic force that supports the thermoelectric element 15 can be adjusted, making it easier to achieve both power generation efficiency and durability of the thermoelectric power generation device 100.

Note that the configurations of the mounting hole 24, the coil spring 75, and the elastic adhesive 56 filled in the mounting hole 24 are limited to those that are applied to the housing 20 and the first heat conductive member 50 as shown in FIG. Although not shown, it may be applied to the heat dissipation member 30 and the second heat conduction member 51.

Next, other modified examples will be explained.

In the embodiment described above, the thermoelectric element 15 is bonded to the first thermally conductive member 50 by a thermally conductive adhesive 55 and to the second thermally conductive member 51 by an elastic adhesive 56. On the other hand, contrary to the above embodiment, the thermoelectric element 15 is bonded to the first heat conductive member 50 or the housing 20 by the elastic adhesive 56, and is bonded to the second heat conductive member 51 or the heat dissipation member by the heat conductive adhesive 55. It may also be bonded to member 30.

Further, the first heat conductive member 50 and the second heat conductive member 51 are not essential configurations, and either one or both may not be provided. That is, the thermoelectric element 15 may be directly attached to the housing 20 and/or the heat dissipation member 30. In this case, the thermoelectric element 15 may be brought into direct contact with the housing 20 or the heat radiating member 30 using the elastic adhesive 56, or when the thermoelectric element 15 is bonded to one of the housing 20 and the heat radiating member 30 using the elastic adhesive 56, the other and may be directly bonded with an adhesive other than the elastic adhesive 56. In other words, the thermoelectric element 15 may be provided so as to be directly or indirectly sandwiched between the housing 20 and the heat radiating member 30 and configured to be able to exchange heat with the housing 20 and the heat radiating member 30.

As described above, when the thermoelectric element 15 is attached to the housing 20 or the heat radiating member 30 using the elastic adhesive 56, it means that the thermoelectric element 15 is directly bonded to the housing 20 or the heat radiating member 30 using the elastic adhesive 56. In addition, the thermoelectric element 15 is bonded to other members such as the first heat conducting member 50 and the second heat conducting member 51 with an elastic adhesive 56, and is attached to the housing 20 or the heat dissipating member 30 via the other member. The meaning also includes the composition. That is, the thermoelectric element 15 may be bonded to at least one of the housing 20 and the heat dissipating member 30 directly or indirectly via the heat conductive member using the elastic adhesive 56. For example, a configuration may be adopted in which the first heat conductive member 50 or the second heat conductive member 51 is attached to the housing 20 or the heat radiating member 30 by being bonded to the first heat conductive member 50 or the second heat conductive member 51 with an elastic adhesive 56. Furthermore, the thermoelectric element 15 is attached to the first heat conductive member 50 or the second heat conductive member 51 by a method other than adhesion using the elastic adhesive 56, and the first heat conductive member 50 or the second heat conductive member 51 is attached to the elastic adhesive. It may be attached to the housing 20 or the heat dissipation member 30 by the material 56. In this way, the elastic adhesive 56 may be included in at least one of the configuration for attaching the thermoelectric element 15 to the housing 20 and the configuration for attaching the thermoelectric element 15 to the heat dissipation member 30.

Further, in the embodiment described above, the thermoelectric element 15 is bonded to the first thermally conductive member 50 using a thermally conductive adhesive 55. In order to improve heat conduction to the thermoelectric element 15, it is preferable to bond it to the first thermal conductive member 50 using a thermally conductive adhesive 55, which has better thermal conductivity than the elastic adhesive 56. The adhesive material between the heat conductive member 50 is not limited to this. Further, the elastic adhesive 56 for bonding the thermoelectric element 15 and the second heat conductive member 51 may be used for bonding the thermoelectric element 15 and the first heat conductive member 50. Alternatively, the thermoelectric element 15 and the first heat conductive member 50 may be simply brought into contact without using an adhesive.

Further, in the embodiment described above, the thermoelectric power generation device 100 is used as a sensor device 101 that detects oil leakage occurring in the hydraulic cylinder 1. On the other hand, the thermoelectric power generation device 100 is not limited to the sensor device 101, and may be used in other devices.

Hereinafter, the configuration, operation, and effects of the embodiments of the present invention will be collectively described.

The thermoelectric power generation device 100 includes a case 10 and a thermoelectric element 15 that is housed in the case 10 and generates an electromotive force according to a temperature difference between a heat absorption surface 15a and a heat radiation surface 15b. a housing 20 thermally connected to the surface 15a; a heat radiation member 30 thermally connected to the heat radiation surface 15b of the thermoelectric element 15; and a housing 20 and the heat radiation member provided sandwiched between the housing 20 and the heat radiation member 30. The thermoelectric element is attached to the housing 20 or the heat radiating member 30 with an elastic adhesive 56 having elasticity.

In this configuration, the thermoelectric element 15 is attached to the housing 20 or the heat radiating member 30 by the elastic adhesive 56, so that dimensional errors or dimensional changes due to temperature changes occur in the housing 20, the heat radiating member 30, and the spacer 40. Also, dimensional errors and dimensional changes can be absorbed by the elasticity of the elastic adhesive 56. Thereby, generation of a gap between the thermoelectric element 15 and the housing 20 or the heat radiating member 30 and compression of the thermoelectric element 15 by the housing 20 and the heat radiating member 30 can be suppressed. Therefore, the power generation efficiency and durability of the thermal power generation device 100 are improved.

Further, in the thermoelectric power generation device 100, the thermoelectric element 15 is bonded to one of the housing 20 and the heat dissipation member 30 by an elastic adhesive 56, and the thermoelectric element 15 is bonded to the housing 20 and the heat dissipating member 30 by a thermally conductive adhesive 55 that has better thermal conductivity than the elastic adhesive 56. 20 and the other of the heat dissipating member 30.

With this configuration, compressive force and tensile force acting on the thermoelectric element 15 can be absorbed by the elastic adhesive 56, while good heat conduction from the other of the housing 20 and the heat dissipation member 30 to the thermoelectric element 15 can be achieved. Therefore, it is possible to more appropriately ensure the power generation efficiency and durability of the thermal power generation device 100.

The thermoelectric power generation device 100 also includes a connecting member 52 provided on one of the housing 20 and the heat radiating member 30 and having a female thread, and a male thread that is inserted through the other of the housing 20 and the heat radiating member 30 and screwed into the connecting member 52. The connecting member 52 and the other of the housing 20 and the heat radiating member 30 through which the resin screw 72 is inserted are spaced apart without contacting each other.

In this configuration, since the connecting member 52 does not come into contact with the heat radiating member 30, the positional relationship between the housing 20 and the heat radiating member 30 is determined by the spacer 40. That is, even if the dimensions of the connecting member 52 vary, the connecting member 52 does not come into contact with the heat radiating member 30, so the connecting member 52 does not interfere with the positioning of the housing 20 and the heat radiating member 30 by the spacer 40. As a result, the housing 20 and the heat dissipation member 30 are properly positioned by the spacer 40, and the connection member 52 comes into contact with the heat dissipation member 30, thereby creating a space between the thermoelectric element 15 and the heat dissipation member 30 (second heat conduction member 51). This can prevent gaps from forming. Thereby, thermal conductivity from the thermoelectric element 15 to the heat radiation member 30 is ensured, and the power generation efficiency of the thermoelectric power generation device 100 can be improved.

In addition, the thermoelectric generator 100 has one end attached to one of the housing 20 and the heat radiating member 30, the thermoelectric element 15 bonded to the other end with an elastic adhesive 56, and the other end attached to the other of the housing 20 and the heat radiating member 30. The spacer 40 further includes a second heat conductive member 51 that supports the thermoelectric element 15 therebetween, and an accommodation groove 40c into which the second heat conductive member 51 is inserted is formed in the inner periphery of the spacer 40.

In this configuration, the elastic adhesive 56 is applied to the tip of the second heat conductive member 51 in a state where the heat dissipating member 30 to which the second heat conductive member 51 is attached and the spacer 40 are assembled. A space C between the tip of the member 51 and the accommodation groove 40c functions as a pocket. Therefore, the elastic adhesive 56 can be stored at the tip of the second heat conductive member 51 to suppress dripping from the tip. As a result, it is possible to improve the adhesion state of the thermoelectric element 15 to the tip of the second heat conductive member 51, thereby absorbing compressive force and tensile force to the thermoelectric element 15, and dissipating heat from the thermoelectric element 15 to the heat dissipating member 30. conduction can be performed effectively.

The thermal power generation device 100 according to the modification further includes a first heat conductive member 50 whose one end is attached to one of the housing 20 and the heat dissipation member 30 and whose other end supports the thermoelectric element 15. A mounting hole 24 is formed in one of the housing 20 and the heat dissipation member 30 to which the first heat conduction member 50 is attached. The first heat conductive member 50 is provided with a coil spring 75 that biases the housing 20 and the heat dissipating member 30 toward the other side. Attached to one side.

In this configuration, the first heat conductive member 50 and the thermoelectric element 15 are elastically supported by the coil spring 75 in addition to the elastic adhesive 56. As a result, the elastic force supporting the thermoelectric element 15 becomes the resultant force of the elastic forces of the elastic adhesive 56 and the coil spring 75. By providing the coil spring 75 in this manner, the elastic force that supports the thermoelectric element 15 can be adjusted, making it easier to achieve both power generation efficiency and durability of the thermoelectric power generation device 100.

A method for manufacturing a thermoelectric power generation device 100 including a thermoelectric element 15 that converts the temperature difference between the housing 20 and the heat dissipation member 30 into electric power includes a step of attaching a first heat conduction member 50 that conducts heat of the housing 20 to the housing 20; A step of attaching a second heat conductive member 51 that conducts the heat of the heat dissipating member 30 to the heat dissipating member 30, a step of attaching a resin spacer 40 to the heat dissipating member 30, and a step of attaching an elastic adhesive 56 to the tip of the second heat conductive member 51. and attaching the thermoelectric element 15, which is electrically connected to the circuit board 81 in advance, to the second heat conductive member 51 using the elastic adhesive 56; A step of attaching a thermally conductive adhesive 55 and a step of attaching the thermoelectric element 15 attached to the second thermally conductive member 51 to the first thermally conductive member 50 attached to the housing 20 by the thermally conductive adhesive 55 attached to the first thermally conductive member 50 attached to the housing 20. 1. Attaching the spacer 40 to the housing 20 while adhering it to the heat conductive member 50.

In this configuration, the thermoelectric element 15 is electrically connected to the circuit board 81 in advance and assembled to the heat dissipation member 30 to form an assembly, and then the assembly and the housing 20 are assembled. According to this configuration, the wiring work is easier compared to the case where the thermoelectric element 15 and the circuit board 81 are electrically wired with the thermoelectric element 15 and the circuit board 81 individually attached to the housing 20 or the heat dissipation member 30. can be easily done. Therefore, the thermal power generation device 100 can be easily manufactured.

Although the embodiments of the present invention have been described above, the above embodiments merely show a part of the application examples of the present invention, and are not intended to limit the technical scope of the present invention to the specific configurations of the above embodiments. do not have.

DESCRIPTION OF SYMBOLS 10... Case, 15... Thermoelectric conversion element, 15a... Heat absorption surface, 15b... Heat radiation surface, 20... Housing (first member), 30... Heat radiation member (second member), 40... Spacer (insulation member), 50... Third 1 heat conductive member (thermal conductive member), 51... second heat conductive member (thermal conductive member), 52... connecting member (first screw member), 55... first adhesive material (thermal conductive adhesive material), 56... Second adhesive (elastic adhesive), 72... Resin screw (second screw member), 75... Coil spring (elastic member), 81... Circuit board, 100... Thermoelectric generator

Claims (3)

case and
a thermoelectric conversion element that is housed in the case and generates an electromotive force according to a temperature difference between a heat absorption surface and a heat radiation surface,
The case is
a first member thermally connected to the endothermic surface of the thermoelectric conversion element;
a second member thermally connected to the heat radiation surface of the thermoelectric conversion element;
a resin-made heat insulating member that is provided between the first member and the second member and insulates the first member and the second member;
The thermoelectric conversion element is attached to the first member or the second member with an elastic adhesive having elasticity,
One end is attached to one of the first member and the second member, the thermoelectric conversion element is attached to the other end with the elastic adhesive, and the other end is attached to the other of the first member and the second member. A thermally conductive member supporting the thermoelectric conversion element is provided between the
A thermal power generation device characterized in that a groove portion into which the heat conductive member is inserted is formed on the inner periphery of the heat insulating member . a first threaded member provided on one of the first member and the second member and formed with a female thread;
further comprising a second threaded member formed with a male thread that is inserted through the other of the first member and the second member and screwed into the female thread of the first threaded member,
The heat exchanger according to claim 1, wherein the first screw member and the other of the first member and the second member through which the second screw member is inserted are spaced apart without contacting each other. Power generation equipment. A mounting hole is formed in one of the first member and the second member to which the heat conductive member is attached, and the one end of the heat conductive member is accommodated in the mounting hole;
The mounting hole is provided with an elastic member that biases the heat conductive member toward the other of the first member and the second member,
The thermal conductive member according to claim 1 or 2, wherein the heat conductive member is attached to one of the first member and the second member by the elastic adhesive filled in the attachment hole together with the elastic member. Power generation equipment.

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