JP7486252B1 - Thermoelement - Google Patents

Abstract

[Problem] To provide a thermoelement in which malfunctions are reduced by a mechanical mechanism without using a complex electric control mechanism, and in which a piston protrudes and retracts in accordance with the volume expansion of a volume expansion body. [Solution] A thermoelement 100 includes a volume expansion body 8 housed in a container 9 and expands and contracts in volume with changes in ambient temperature, a first piston 4 operated by the volume change of the volume expansion body due to changes in the ambient temperature of the container, a second piston 10 having a diameter different from that of the first piston and operated by the volume change of the volume expansion body due to changes in the ambient temperature of the container, a first sealing member 7 disposed at one end of the container and having a first through hole, and a second sealing member 11 disposed at the other end of the container and having a second through hole having a diameter different from that of the first through hole, the first piston slidably penetrating the first sealing member, the second piston slidably penetrating the second sealing member, and the tips of the first piston and the second piston come into direct or indirect contact with each other within the container. [Selected Figure] Figure 1

Description

The present invention relates to a thermoelement, and more specifically to a thermoelement used in a thermostat device, etc.

Conventionally, a thermostat device (also called a thermoactuator) has been used to open and close the valve of a cooling device in an automobile, etc., using a thermoelement that contains a thermal expansion body that expands and contracts in response to temperature changes in the object to be detected and has a piston that is actuated by the change in volume of the thermal expansion body.

In extremely cold environments such as those found in North America, with conventional exhaust heat recovery devices, the heat from the exhaust gases generated when starting an engine, such as that of a car, is absorbed by the heat exchanger, and the moisture contained in the exhaust gases is frozen inside the muffler by the outside air, preventing the exhaust gases from being discharged properly.

As one such measure, an electrically controlled thermoactuator such as that described in Patent Document 1 is used.

Conventional electrically controlled thermoactuator structures involve placing a heater inside a thermoelement, and when electricity is applied to the heater in an extremely low temperature environment, it forcibly melts the wax inside the thermoelement, which is a thermal expansion material, and the wax expands in volume, pushing up and operating the piston.

Patent No. 7126475

However, with the mechanism of Patent Document 1, when the heater is energized, the heat from the heater is not transferred to the wax in the housing cup due to the thermal conductivity, but escapes to the metal cup, and the desired operation cannot be obtained.

The present invention was devised to solve the above problems, and its purpose is to provide a thermoelement that reduces malfunctions using a mechanical mechanism without using a complex electrical control mechanism, and improves the degree of freedom in the amount of protrusion and recession by protruding and recessing the piston into the housing cup according to the degree of volume expansion of the volume expansion body.

The thermoelement according to the first invention is a thermoelement comprising a container, a volume expansion body housed in the container and expanding and contracting in volume with changes in ambient temperature, a first piston that operates with the change in volume of the volume expansion body due to changes in the ambient temperature of the container, a second piston that has a different diameter from the first piston and operates with the change in volume of the volume expansion body due to changes in the ambient temperature of the container, a first sealing member that is disposed at one end of the container and has a first through hole, and a second sealing member that is disposed at the other end of the container and has a second through hole that has a different diameter from the first through hole, characterized in that the first piston slidably penetrates the first sealing member, the second piston slidably penetrates the second sealing member, and the tips of the first piston and the second piston come into direct or indirect contact with each other within the container.

The thermoelement according to the second invention is the thermoelement according to the first invention, characterized in that the first piston and the second piston are respectively biased in a retreating (returning) direction by a first biasing force from a first biasing member and a second biasing force from a second biasing member, and the magnitude of the first biasing force is greater than the second biasing force.

The thermoelement according to a third aspect of the present invention is characterized in that, in the second aspect, the relationship between the first biasing force and the second biasing force is configured to satisfy the following relational expression (1).

The thermoelement according to the fourth invention is the third invention, characterized in that it has a locking structure that stops the first piston at a predetermined protruding amount even if the ambient temperature rises.

The thermoelement according to the fifth invention is the thermoelement according to the fourth invention, characterized in that the first piston is provided with a stopper to prevent the first piston from penetrating the container more than a predetermined distance.

The thermoelement according to the sixth invention is the thermoelement according to the fifth invention, characterized in that the first sealing member and the second sealing member are integrally configured to form a sealing member, and the first piston and the second piston are configured to come into direct or indirect contact with each other within a through hole of the sealing member.

The thermoelement according to the seventh invention is the fifth or sixth invention, characterized in that the second piston has a cover equipped with a stopper mechanism to prevent the second piston from sinking to a predetermined extent.

The thermoelement according to the eighth invention is the fifth or sixth invention, characterized in that the second piston is provided with a stopper mechanism to prevent the second piston from sinking to a predetermined extent.

The thermoelement according to the ninth invention is the fifth or sixth invention, characterized in that it has a lid on the first piston side that moves integrally with the container, and is configured so that the stopper and the lid are engaged by the first biasing member.

According to the first to ninth inventions, it is possible to realize a thermoelement that eliminates malfunctions using a mechanical mechanism without using a complex electrical control mechanism, and improves the degree of freedom in the amount of protrusion and recession by protruding and recessing the piston into the cup according to the degree of volume expansion of the volume expansion body.

FIG. 1 is a cross-sectional view showing the structure of a thermo-element according to an embodiment of the present invention. FIG. 2(a) is a diagram for explaining an image of the operation of the thermo-element in response to the change in the ambient temperature in FIG. 1, and FIG. 2(b) is a diagram for explaining the state of FIG. 2(a). FIG. 3 is a characteristic diagram showing the relationship between the temperature of the thermoelement in FIG. 2(a) and the amount of projection and recession. FIG. 4 is a characteristic diagram showing the relationship between the temperature and the wax volume of the thermoelement of FIG. FIG. 5(a) is a detailed explanatory diagram of the operation image in the temperature range between A and B degrees Celsius in FIG. 2(a), and FIG. 5(b) is a characteristic diagram showing the relationship between the temperature of the thermoelement and the amount of protrusion and recession in the temperature range between A and B degrees Celsius. FIG. 6(a) is a detailed explanatory diagram of the operation image in the temperature range between B and C°C in FIG. 2(a), and FIG. 6(b) is a characteristic diagram showing the relationship between the temperature of the thermoelement and the amount of protrusion and recession in the temperature range between B and C°C. FIG. 7(a) is a detailed explanatory diagram of the operation image at C°C in FIG. 2(a), and FIG. 7(b) is a characteristic diagram showing the relationship between the temperature of the thermo-element at C°C and the amount of projection and recession. FIG. 8(a) is a detailed explanatory diagram of the operation image in the temperature range of C-D°C in FIG. 2(a), and FIG. 8(b) is a characteristic diagram showing the relationship between the temperature of the thermoelement and the amount of protrusion and recession in the temperature range of C-D°C. FIG. 9(a) is a detailed explanatory diagram of the operation image at D° C. in FIG. 2(a), and FIG. 9(b) is a characteristic diagram showing the relationship between the temperature of the thermo-element at D° C. and the amount of projection and recession. FIG. 10(a) is a detailed explanatory diagram of the operating image in the temperature range between D and E degrees Celsius in FIG. 2(a), and FIG. 10(b) is a characteristic diagram showing the relationship between the temperature of the thermoelement and the amount of protrusion and recession in the temperature range between D and E degrees Celsius. FIG. 11(a) is a detailed explanatory diagram of the operation image of FIG. 2(a) at E° C. or higher, and FIG. 11(b) is a characteristic diagram showing the relationship between the temperature of the thermoelement and the amount of projection and depression when operating at E° C. or higher. FIG. 12 is an image diagram showing the use of a thermoactuator to which the present invention is applied, where (a) is when the cooling water is at a low temperature, (b) is when the cooling water is at a medium temperature, and (c) is when the cooling water is at a high temperature. FIG. 13 is a cross-sectional view showing the structure of a thermo-element according to another embodiment of the present invention. FIG. 14 is a characteristic diagram showing the relationship between the temperature and the amount of projection and recession of a conventional thermo-element.

The thermoelement according to the embodiment of the present invention will be described in detail below with reference to the drawings.

The thermoelement of this embodiment is characterized by comprising a container (housing cup), a volume expansion body housed in the container and expanding and contracting in volume with changes in ambient temperature, a first piston that operates with the volume change of the volume expansion body due to changes in the ambient temperature of the container, a second piston that has a different diameter from the first piston and operates with the volume change of the volume expansion body due to changes in the ambient temperature of the container, a first sealing member that is disposed at one end of the container and has a first through hole, and a second sealing member that is disposed at the other end of the container and has a second through hole that has a different diameter from the first through hole, and is configured such that the first piston slidably penetrates the first sealing member, the second piston slidably penetrates the second sealing member, and the tips of the first piston and the second piston come into direct or indirect contact with each other within the container. This makes it possible to reduce malfunctions with a mechanical mechanism without using a complex electrical control mechanism, and to realize a thermoelement in which the piston protrudes and retracts with the volume expansion of the volume expansion body.

<Thermoelement configuration>
The configuration of a thermo-element 100 according to an embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is a cross-sectional view showing the configuration of a thermo-element 100 according to an embodiment of the present invention, and shows the configuration of a packing type thermo-element.

As shown in FIG. 1, the thermoelement 100 according to the embodiment of the present invention includes a spring (low load) 1, a spring (high load) 2, a lid 3, a piston (large diameter) 4, a cover 5, a seal (backup ring) 6, a packing (large diameter) 7, a volume expansion body 8, a housing cup 9, a piston (small diameter) 10, a packing (small diameter) 11, a seal (backup ring) 12, and a cover 13.

<Explanation of the thermoelement configuration>
Thermoelement 100 uses a piston (large diameter) 4 and a piston (small diameter) 10 of different diameters, a high load spring 2, a low load spring 1, and a housing cup 9 that penetrates vertically, and autonomously controls piston 4 and piston 10 in response to changes in the ambient temperature, and by combining it with various locking structures, improves the freedom to change the desired amount of protrusion and retraction.

Spring 1 is a low-load spring that generates a biasing force. Spring 1 is engaged with housing cup 9. Spring 1 constitutes the second biasing member.

Spring 2 is a high-load spring that is engaged with the flange of piston 4 and lid 3. Spring 2 constitutes the first biasing member.

The lid 3 functions as a stopper for the piston 4.

Piston 4 is a stainless steel piston rod that can be freely extended and retracted, and constitutes a large-diameter piston that serves as the first piston.

The cover 5 serves as a lid for the housing cup 9.

Seal 6 is a backup ring.

The packing 7 is a rubber seal packing (sealing member) for the piston 4. The packing 7 constitutes the first sealing member.

The volume expansion body 8 is enclosed in a housing cup 9 and expands and contracts in volume due to changes in the ambient temperature. The volume expansion body 8 changes the volume of the housing cup 9 in response to changes in the ambient temperature, thereby operating the piston (large diameter) 4 and/or the piston (small diameter) 10. The volume expansion body 8 is, for example, a wax such as paraffin wax. In the following, in this embodiment, an example in which wax is used as the volume expansion body 8 will be described.

The housing cup 9 is a container made of metal such as brass in which a volume expansion body (e.g., wax) 8 is enclosed.

Piston 10 is a stainless steel piston rod that can be freely extended and retracted, and constitutes a small-diameter piston that serves as a second piston having a different diameter from piston 4.

The packing 11 is a rubber seal packing (sealing member) for the piston 10. The packing 11 constitutes a second sealing member.

Seal 12 is a backup ring.

The cover 13 serves as a lid for the piston 10 side of the housing cup 9.

The pistons 4 and 10 are configured so that their tips come into direct or indirect contact with each other, and as the temperature around the thermoelement 100 rises, the wax 8 in the housing cup 9 expands, causing the pistons 4 and 10 to operate autonomously, causing the piston 4 to protrude from the housing cup 9. Of course, the wax enclosed in the housing cup 9 is not limited to paraffin wax, and any material that has a predetermined thermal expansion characteristic with a relatively large volume change, such as micro wax, can be applied to the present invention.

Figure 2(a) is a diagram for explaining the operation image of the thermoelement in the ambient temperature change of Figure 1, and Figure 2(b) is a diagram for explaining the state of Figure 2(a). Figure 3 is a characteristic diagram showing the relationship between the temperature of the thermoelement of Figure 2(a) and the amount of protrusion and recession. Figure 4 is a characteristic diagram showing the relationship between the temperature of the thermoelement of Figure 2(a) and the wax volume and amount of protrusion and recession. Here, the amount of protrusion and recession refers to the length of protrusion and recession of the thermoelement from the initial position of the tip of the thermoelement in the protruding direction (direction to protrude) or the retracting direction (direction to return). This amount of protrusion and recession is determined by the location where the thermoelement 100 is mounted, and the determined amount of protrusion and recession is called the predetermined amount of protrusion and recession. In addition, the value of the operating range of the piston 4 or piston 10 is determined, and the determined value is called the predetermined value. The piston 4 or piston 10 is configured not to operate above the predetermined value.

Below, we will explain the overall operation of the thermoelement according to an embodiment of the present invention using Figures 2(a) and (b), 3, and 4.

As shown in Figure 2 (a), when the ambient fluid temperature changes from a low temperature range to a high temperature range, the state of the wax changes, and in the temperature ranges between A and B °C, between B and C °C, at C °C, between C and D °C, at D °C, between D and E °C, and above E °C, as shown in Figure 2 (b), in the temperature range between A and B °C, the wax is solid and the volume is small. In the temperature range between B and C °C, the wax is partially melted and the volume is small. At C °C, the wax is partially melted and the volume is medium. In the temperature range between C and D °C, the wax is partially melted and the volume is medium. At D °C, the wax is partially melted and the volume is medium. In the temperature range between D and E °C, the wax is partially melted and the volume is large. At E °C and above, the wax is liquid and the volume is maximum.

In a typical thermoelement with one piston, the wax volume expands as the temperature rises and contracts as the temperature drops, as shown in Figure 4. In Figure 4, the vertical axis represents the wax volume ( ^mm3 ) and the horizontal axis represents the temperature (°C).

In a typical thermoelement with one piston, for example, if the protruding/recessing length _Q1 is the initial value and the monotonically increasing (decreasing) protruding/recessing lengths _Q2 , _Q3 , _Q4 , and _Q5 are the protruding/recessing lengths, _Q1 , _Q2 , _Q3 , _Q4 , and _Q5 , as shown in FIG. 14, the thermoelement tip displaces upward with increasing temperature and decreases with decreasing temperature, and the protruding/recessing length changes in monotonically increasing (decreasing) amount. In FIG. 3, the vertical axis is the protruding/recessing amount (mm) and the horizontal axis is the temperature (°C). The temperature ranges in FIG. 3 and FIG. 4 only need to satisfy the relationship A<B<C<D<E, and change depending on the use of the thermoelement, so that FIG. 3 is a conceptual diagram (image diagram) and does not show a specific temperature. The same applies to FIG. 5(b) to FIG. 11(b) described later.

As shown in Figure 3, in the thermoelement of the present invention, due to the autonomous operation of the large diameter piston 4 and the small diameter piston 10, the action of the high load spring 2 and the low load spring 1, and the action of various locking structures, even if the wax becomes liquid after the protrusion/recess length changes by a certain amount due to the volume change accompanying the change in the state of the wax, some volume expansion occurs, resulting in the relationship between the protrusion/recess amount and the temperature characteristics as shown in Figure 3.

Figure 5(a) is a detailed explanatory diagram of the operation image in the temperature range between A and B°C in Figure 2(a), and Figure 5(b) is a characteristic diagram showing the relationship between the temperature of the thermoelement and the amount of protrusion and recession when operating in the temperature range between A and B°C.

5(a) shows the state (starting point) in which the tip of the thermoelement is at the protruding/retracting length _P1 in the low temperature range, with the piston (large diameter) 4 being pushed in the direction of sinking into the housing cup 9 by the return load of the spring (heavy load) 2, and the wax 8 being in its smallest volume because it is in a solid wax state. Because the piston (large diameter) 4 is pushed in the direction of sinking into the housing cup 9, the piston (small diameter) 10 is pushed in the direction of protruding from the housing cup 9, and the tip of the thermoelement is positioned at the protruding/retracting length _P1 .

Here, the spring (high load) 2 must have a load that can push out the piston (small diameter) 10 and deflect the spring (low load) 1. If the load is low, the piston (large diameter) 4 cannot push the piston (small diameter) 10 in the direction protruding from the housing cup 9, and there is no displacement.

Figure 5(b) shows the state in which the wax 8 is solid. Because the wax 8 is solid, its volume is smallest, and the return load of the spring (heavy load) 2 pushes the piston (large diameter) 4 in the direction of sinking into the housing cup 9. As the piston (large diameter) 4 is pushed in the direction of sinking into the housing cup 9, the piston (small diameter) 10 is pushed in the direction of protruding from the housing cup 9.

Figure 6(a) is a detailed explanatory diagram of the operation image in the temperature range between B and C°C in Figure 2(a), and Figure 6(b) is a characteristic diagram showing the relationship between the temperature between B and C°C and the amount of protrusion and recession of the tip of the thermoelement.

6(a) shows the state in which the tip of the thermoelement is displaced from protruding/recessed length _P1 to protruding/recessed length _P2 in the temperature range between B and C° C. In the temperature range between B and C° C., the wax 8 is partially melted, and the volume expands more than in the temperature range between A and B° C., and internal pressure is generated in the housing cup 9 to protrude the piston (small diameter) 10 and the piston (large diameter) 4 from within the housing cup 9 against the biasing forces of the spring (low load) 1 and the spring (high load) 2. The cross-sectional area of the piston (large diameter) 4 and the biasing force generated by the spring (high load) 2 are set so that the force generated by the internal pressure to cause the piston (large diameter) 4 to protrude from the housing cup 9 is greater than the biasing force generated by the spring (high load) 2, and the cross-sectional area of the piston (small diameter) 10 and the biasing force generated by the spring (low load) 1 are set so that the force generated by the internal pressure to cause the piston (small diameter) 10 to protrude from the housing cup 9 is smaller than the biasing force generated by the spring (low load) 1. Therefore, when the tips of the piston (large diameter) 4 and the piston (small diameter) 10 are in contact, the piston (large diameter) 4 moves in the direction protruding from the housing cup 9, and the piston (small diameter) 10 moves in the direction sinking into the housing cup 9.

As shown in FIG. 6(b), the amount of volumetric expansion of the wax 8 must match the total volume of the piston (large diameter) 4 and piston (small diameter) 10 protruding and sinking from the housing cup 9. Therefore, the piston (large diameter) 4 and piston (small diameter) 10 protrude and sink from the housing cup 9 in accordance with the amount of volumetric expansion of the wax 8 that corresponds to the temperature in the temperature range between B and C degrees Celsius, and as a result, the tip of the thermoelement is positioned in the range of protrusion/recession amount _P1 to protrusion/recession length _P2 that corresponds to the temperature in the temperature range between B and C degrees Celsius.

Figure 7(a) is a detailed explanatory diagram of the operation image at C°C in Figure 2(a), and Figure 7(b) is a characteristic diagram showing the relationship between the temperature at C°C and the tip projection length of the thermoelement.

7(a) shows the state where the tip of the thermo-element is located at protruding/retracting length _P2 at C° C. At C° C, the wax 8 melts and expands in volume more than in the temperature range between B and C° C. Internal pressure is generated within the housing cup 9 to protrude the piston (small diameter) 10 and the piston (large diameter) 4 from within the housing cup 9 against the biasing forces of the spring (low load) 1 and the spring (high load) 2. The cross-sectional area of the piston (large diameter) 4 and the biasing force generated by the spring (high load) 2 are set so that the force generated by the internal pressure to cause the piston (large diameter) 4 to protrude from the housing cup 9 is greater than the biasing force generated by the spring (high load) 2, and the cross-sectional area of the piston (small diameter) 10 and the biasing force generated by the spring (low load) 1 are set so that the force generated by the internal pressure to cause the piston (small diameter) 10 to protrude from the housing cup 9 is smaller than the biasing force generated by the spring (low load) 1. Therefore, when the tips of the piston (large diameter) 4 and the piston (small diameter) 10 are in contact, the piston (large diameter) 4 moves in a direction protruding from the housing cup 9, and the piston (small diameter) 10 attempts to move in a direction to sink into the housing cup 9, but a stopper provided on the piston (small diameter) 10 comes into contact with the cover 13, and the piston (small diameter) 10 cannot move further in a direction to sink into the housing cup 9.

As shown in FIG. 7(b), the tip of the thermo-element is located within the range of the protruding length _P2 .

Figure 8 (a) is a detailed explanatory diagram of the operation image in the temperature range between C and D°C in Figure 2 (a), and Figure 8 (b) is a characteristic diagram showing the relationship between the temperature in the temperature range between C and D°C and the amount of protrusion and recession of the tip of the thermoelement.

8(a) shows a state in which the tip of the thermo-element is located at the protruding/retracting length _P2 in the temperature range between C and D° C. In the temperature range between C and D° C., the wax 8 partially melts, causing a greater volume expansion than at temperature C° C., and internal pressure is generated within the housing cup 9 as it tries to protrude the piston (small diameter) 10 and the piston (large diameter) 4 from within the housing cup 9 against the biasing forces of the spring (low load) 1 and the spring (high load) 2. The cross-sectional area of the piston (large diameter) 4 and the biasing force generated by the spring (high load) 2 are set so that the force generated by the internal pressure to cause the piston (large diameter) 4 to protrude from the housing cup 9 is greater than the biasing force generated by the spring (high load) 2, and the cross-sectional area of the piston (small diameter) 10 and the biasing force generated by the spring (low load) 1 are set so that the force generated by the internal pressure to cause the piston (small diameter) 10 to protrude from the housing cup 9 is smaller than the biasing force generated by the spring (low load) 1, and since the stopper provided on the piston (small diameter) 10 contacts the cover 13 and the piston (small diameter) 10 cannot move in the direction of sinking into the housing cup 9, only the piston (large diameter) 4 moves in the direction of protruding from the housing cup 9.

8(b), the piston (small diameter) 10 does not move in the direction of either sinking or protruding from the housing cup 9, so the tip of the thermo-element is located within the range of the protruding/retracting length _P2 . The amount of protrusion/retraction of the protruding/retracting length _P2 can be adjusted by adjusting the thickness of the stopper provided on the piston (small diameter) 10.

Figure 9(a) is a detailed explanatory diagram of the operation image at D°C in Figure 2(a), and Figure 9(b) is a characteristic diagram showing the relationship between the temperature at D°C and the amount of protrusion and recession of the thermoelement tip.

9(a) shows the state where the tip of the thermo-element is located at protruding/retracting length _P2 at D° C. At D° C., the wax 8 melts and expands in volume more than in the temperature range between C and D° C., and internal pressure is generated within the housing cup 9 to protrude the piston (small diameter) 10 and the piston (large diameter) 4 from within the housing cup 9 against the biasing forces of the spring (low load) 1 and the spring (high load) 2. The cross-sectional area of the piston (large diameter) 4 and the biasing force generated by the spring (high load) 2 are set so that the force generated by the internal pressure to cause the piston (large diameter) 4 to protrude from the housing cup 9 is greater than the biasing force generated by the spring (high load) 2, and the cross-sectional area of the piston (small diameter) 10 and the biasing force generated by the spring (low load) 1 are set so that the force generated by the internal pressure to cause the piston (small diameter) 10 to protrude from the housing cup 9 is smaller than the biasing force generated by the spring (low load) 1. Furthermore, since the stopper provided on the piston (small diameter) 10 contacts the cover 13 and the piston (small diameter) 10 cannot move in the direction to sink into the housing cup 9, in the temperature range between C and D degrees Celsius, only the piston (large diameter) 4 moves in the direction to protrude from the housing cup 9, but at D degrees Celsius, the piston (large diameter) 4 contacts the lid 3 and the piston (large diameter) 4 cannot move in the direction to protrude from the housing cup 9.

As shown in FIG. 9(b), the tip of the thermo-element is located at a protruding length _P2 .

Figure 10 (a) is a detailed explanatory diagram of the operation image of the temperature range between D and E °C in Figure 2 (a), and Figure 10 (b) is a characteristic diagram showing the relationship between the temperature in the temperature range between D and E °C and the protruding length of the thermoelement tip.

10(a) shows a state in which the tip of the thermoelement is displaced from the protruding/recessed length _P2 to the protruding/recessed length _P3 in the temperature range between D and E°C. In the temperature range between D and E°C, the wax 8 is partially melted, and the volume expands more than at D°C, and internal pressure is generated in the housing cup 9 to make the piston (small diameter) 10 and the piston (large diameter) 4 protrude from the housing cup 9 against the biasing force of the spring (low load) 1 and the spring (high load) 2. A force is applied to make the piston (large diameter) 4 protrude from the housing cup 9 due to the internal pressure, but the piston (large diameter) 4 comes into contact with the lid 3 and cannot move in the direction protruding from the housing cup 9, and the piston (small diameter) 10 moves in the direction protruding from the housing cup 9 by the amount of the volume expansion of the wax 8 compared to D°C, against the biasing force generated by the spring (low load) 1.

As shown in Figure 10 (b), the amount of volumetric expansion of the wax 8 must be the same as the total volume of the piston (large diameter) 4 and piston (small diameter) 10 protruding from and sinking in the housing cup 9. Therefore, in accordance with the amount of volumetric expansion of the wax 8 that corresponds to the temperature in the temperature range between D and E degrees Celsius, the piston (large diameter) 4 protrudes from the housing cup 9 until it comes into contact with the lid 3, and the piston (small diameter) 10 moves in the direction of protruding from the housing cup 9, so that the tip of the thermoelement is positioned in the range from protruding and retracting length _P2 to protruding and retracting length _P3 that corresponds to the temperature in the temperature range between D and E degrees Celsius.

Figure 11(a) is a detailed explanatory diagram of the operation image in the temperature range above E°C in Figure 2(a), and Figure 11(b) is a characteristic diagram showing the relationship between the temperature in the temperature range above E°C and the protruding length of the thermoelement tip.

In FIG. 11(a), in the temperature range above E°C, the wax 8 is completely melted, and the volume expansion is greater than in the temperature range between D-E°C, and internal pressure is generated in the housing cup 9 to force the piston (small diameter) 10 and the piston (large diameter) 4 to protrude from the housing cup 9 against the biasing force of the spring (low load) 1 and the spring (high load) 2. A force is applied to the piston (large diameter) 4 to protrude from the housing cup 9, generated by the internal pressure, but the piston (large diameter) 4 comes into contact with the lid 3 and cannot move in the direction protruding from the housing cup 9, and the piston (small diameter) 10 moves in the direction protruding from the housing cup 9 by the amount of volume expansion of the wax 8 compared to when it was at D°C, against the biasing force generated by the spring (low load) 1.

11(b), since the amount of volume expansion of the wax 8 must match the total volume of the piston (large diameter) 4 and piston (small diameter) 10 protruding from the housing cup 9, the piston (large diameter) 4 protrudes from the housing cup 9 until it comes into contact with the lid 3, and the piston (small diameter) 10 moves in the direction protruding from the housing cup 9, according to the amount of volume expansion of the wax 8 corresponding to the temperature in the temperature range between D and E°C, so that the tip of the thermoelement is positioned at a protruding/retracting length of _P3 or more corresponding to the temperature in the temperature range of E°C or higher. Note that the liquid phase volume expansion rate of the wax 8 in the temperature range of E°C or higher is smaller than the melting volume expansion rate in the temperature range between D and E°C, so the displacement gradient with respect to the temperature of the tip of the thermoelement in the temperature range of E°C or higher is smaller than that in the temperature range between D and E°C.

Figure 12 is an image diagram of the use of a thermoactuator to which the present invention is applied, where (a) is when the cooling water is at a low temperature, (b) is when the cooling water is at a medium temperature, and (c) is when the cooling water is at a high temperature. In Figures 12(a), (b), and (c), the thick arrows indicate the flow of exhaust gas, and the dashed arrows indicate the flow of cooling water.

As shown in Figures 12(a), (b), and (c), by using the thermoelement 120 of the present invention, the valve 122 in the flow path through which exhaust gas flows to the heat exchanger 121 can be switched from open to closed to open as the temperature of the cooling water increases. The configuration of the thermoelement 120 of the present invention is as shown in Figure 1 or Figure 13 above, so a description thereof will be omitted here.

Figure 13 is a cross-sectional view showing the configuration of a thermoelement according to another embodiment of the present invention. The thermoelement 200 shown in Figure 13 shows a sleeve-type thermoelement configuration, and since the configuration other than the configuration of the sleeve 14 and the seals 6', 12' is the same as that of the thermoelement in Figure 1, a description will be omitted and only the different configuration will be described.

The first sealing member and the second sealing member are integrally configured to form a sealing member, and the first piston and the second piston are configured to come into direct or indirect contact within the through hole of the sealing member. With the sleeve-type configuration, the piston is protected by the sleeve, so reliability can be improved compared to a packing type without a sleeve.

In this way, the thermoelement of this embodiment and other embodiments does not use heater heat, so there is no problem of heat loss and inoperability, and it can be operated in a low-temperature environment. In the case of water or an aqueous solution, there is a problem that the melting point cannot be selected arbitrarily and the expansion coefficient is small, but since paraffin wax can be used, it can operate at any temperature and has a large expansion coefficient, so it is superior to the thermoelement of Patent Publication No. 6399585, which uses two types of thermal expansion bodies. Instead of a complex electric control mechanism, wax is simply sealed inside the pellet of the existing configuration, so the number of parts is reduced and manufacturing costs are low. Since no electric control mechanism is required, it is smaller and the parts cost is lower than that of a conventional electric control thermoactuator. Since assembly of the electric control mechanism is not required, productivity is improved. In addition to the operation of a normal thermostat, it is possible to operate again, so it can be used in other fields with operations such as opening the valve at extremely low temperatures, closing the valve at room temperature, and opening the valve at high temperatures (or closing the valve at low temperatures, opening the valve at room temperature, and closing the valve at high temperatures). Because it operates autonomously, there is no need for wiring or drive control devices on the vehicle side.

The above provides a detailed explanation of the thermoelement according to the embodiment of the present invention, but the above-mentioned and illustrated embodiments are merely examples of the present invention. Therefore, the technical scope of the present invention should not be interpreted in a limiting manner. In particular, the materials of each component are merely examples, and it goes without saying that they can be appropriately changed to other materials having equivalent strength.

100, 200: Thermoelement 1: Spring (second biasing member)
2: Spring (first biasing member)
3: Lid 4: Piston (first piston)
5: Cover (large diameter)
6: Seal (backup ring)
6': Seal (backup ring)
7: Packing (sealing material)
8: Volume expansion body 9: Housing cup 10: Piston (second piston)
11: Packing (sealing member)
12: Seal (backup ring)
12': Seal (backup ring)
13: Cover (small diameter)
14: Sleeve (sealing member)
120: Thermoelement 121: Heat exchanger 122: Valve

Claims (9)

A thermoelement,
A container;
a volume expansion body that is accommodated in the container and expands and contracts in volume in response to changes in ambient temperature;
A first piston that operates by a volume change of the volume expansion body due to a change in the ambient temperature of the container;
a second piston having a different diameter from the first piston and operating in response to a change in volume of the volume expansion body caused by a change in the ambient temperature of the container;
a first sealing member disposed at one end of the container and having a first through hole;
a second sealing member disposed at the other end of the container and having a second through hole having a diameter different from that of the first through hole;
Equipped with
the first piston slidably passes through the first sealing member, and the second piston slidably passes through the second sealing member;
A thermoelement, characterized in that a tip of the first piston and a tip of the second piston are configured to be in direct or indirect contact with each other within the container. A first biasing force by a first biasing member and a second biasing force by a second biasing member are respectively biased in a retreating (returning) direction on the first piston and the second piston,
2. The thermoelement according to claim 1, wherein the first biasing force is greater than the second biasing force. 3. The thermoelement according to claim 2, characterized in that the relationship between the first biasing force and the second biasing force is configured to satisfy the following relational expression (1).

The thermoelement according to claim 3, characterized in that it has a locking structure that stops the first piston at a predetermined protruding amount even if the ambient temperature rises. The thermoelement according to claim 4, characterized in that the first piston is provided with a stopper to prevent the first piston from penetrating the container more than a predetermined distance. The thermoelement according to claim 5, characterized in that the first sealing member and the second sealing member are integrally configured to form a sealing member, and the first piston and the second piston are configured to come into direct or indirect contact with each other within the through hole of the sealing member. The thermoelement according to claim 5 or 6, characterized in that the second piston has a cover equipped with a stopper mechanism to prevent the second piston from sinking to a predetermined extent. The thermoelement according to claim 5 or 6, characterized in that the second piston is provided with a stopper mechanism to prevent the second piston from sinking to a predetermined extent. The thermoelement according to claim 5 or 6, characterized in that the first piston has a lid that moves integrally with the container, and the first biasing member is configured to engage the stopper and the lid.

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