JP7455361B2 - wax thermo actuator - Google Patents

Description

The present invention relates to a wax thermoactuator in an electronically controlled thermostat device that performs variable water temperature control in a cooling water temperature control system that variably controls the cooling water temperature of an internal combustion engine used in, for example, an automobile. More specifically, the present invention relates to a wax thermoactuator that has a heat generating means inside a piston, and has a heat generating means that heats and melts wax with the heat generating means and converts the volumetric expansion into a piston thrusting and retracting motion.

Conventionally, non-electronic thermostats have been selected to control the water temperature to a low level in advance, assuming high-load operation. However, with electric control, when the engine is operating under high load, the thermostat can be opened even if the cooling water temperature is lower than the wax melting temperature. In areas where the engine is operated under low load (regular use area), a thermostat that uses wax that melts at a higher temperature than before to control the cooling water temperature at a higher temperature when the power is not applied can be used. As a result, the fuel efficiency can be improved in the regular use range.

As a wax thermoactuator having this type of heat generation means, for example, Patent Document 1 discloses a cylinder container 3 that moves forward and backward with respect to a piston 4 fixed in a housing 40, and a cylinder container 3 that is provided in the cylinder container 3 and that changes temperature. A thermostat device 1 is disclosed that includes a wax W that moves a cylinder container 3 forward and backward due to volume changes caused by the change in volume, and a heating element 12 that is provided in a casing 15 of a piston 4 and that applies heat to the wax W when energized. .

The heating element 12 of this thermostat device 1 is composed of a thermally conductive extension member 16 formed penetrating from outside the casing 15 of the piston 4 into the casing 15, a heating portion 18 formed in the extension member 16 inside the casing 15, and an electrode portion 17 formed on the extension member 16 outside the casing 15 and electrically connected to the heating portion 18. A terminal 21 that supplies voltage to the heating portion 18 abuts against the electrode portion 17, electrically connecting the voltage supply source and the heating portion 18, making it highly durable and easy to assemble and maintain (see claim 1 of Patent Document 1, paragraphs [0016] to [0029] of the specification, and Figures 1 and 2 of the drawings, etc.).

However, in the thermostat device 1 equipped with the heat generating element 12 described in Patent Document 1, when the piston 4 provided with the heat generating element 12 lifts and rises, the heat generating element 12, which is a heat source, also rises. Therefore, as the piston 4 rises, the wax near the internal bottom surface separates from the heat source, and the paraffin wax, which has low thermal conductivity, blocks the heat, preventing the wax near the internal bottom surface away from the heat source from thermally expanding. However, there was a problem in that the desired amount of lift could not be obtained.

Furthermore, as a technique for efficiently transmitting the heat generated by the heat generating means to the wax, Patent Document 2 discloses that the actuating piston 7 is enclosed in the cylindrical cases 2 and 3 and moves back and forth outside the case by changing the volume due to the temperature change. A thermoelement 1 is disclosed that includes a thermal expansion body 4 for operation and a heating element 12 disposed inside a case and exerting a thermal influence on the thermal expansion body.

In this thermoelement 1, a heating element 12 has a substantially cylindrical shape, and is disposed in a state in which it is embedded in wax 4, which is a thermally expandable body, at a substantially central position within a case. An electrode member 13 is disposed inside the heating element 12 and is connected to an external power source via a terminal take-out portion 5 provided at the end of the case opposite to the piston. A plate spring material 14 that also serves as a heat radiation fin for radiating heat to the wax 4 is disposed on the outside of the heating element 12 and between the inner wall of the case and the heat generating element 12 .

Therefore, according to the thermoelement 1 described in Patent Document 2, the temperature of the wax 4 sealed in the case can be efficiently raised throughout the entire body, and the temperature can be reliably raised at the terminal extraction portion for controlling the power supply to the heating element 12. It is said that a seal structure can be obtained (see claim 1 of patent document 2, paragraphs [0031] to [0040] of the specification, FIGS. 1 and 2 of the drawings, etc.).

However, in the thermoelement 1 described in Patent Document 2, the heat generating element 12 that is the heat source is fixed, so although the above-mentioned problem does not occur, the heat generated by the heat generating element 12 is transferred to the leaf spring material with high thermal conductivity. It escapes from the cylindrical case 2 which contacts the leaf spring material 14 via the cylindrical case 14. For this reason, the amount of wax that does not reach the heat generated by the heating element 12 increases, resulting in a problem that a desired lift amount cannot be obtained.

Therefore, in order to solve these problems, the applicant proposed a wax thermoactuator described in Patent Document 3. The wax thermoactuator described in Patent Document 3 incorporates a heat transfer pipe with good thermal conductivity around the piston rod, so that the heat from the heater is transmitted to the entire wax in the cup, homogenizing the temperature inside the wax. , it was possible to increase the amount of lift in the temperature region near the melting point of wax (wax is a solid region).

However, in the wax thermoactuator described in Patent Document 3, there is a part where the heat transfer pipe and the cup come into contact, and the heat from the heater radiates directly to the cooling water from there, and the heat generated by the heater is transferred to the wax thermoactuator. There was a problem that it could not be used efficiently for melting. For this reason, in the wax thermoactuator described in Patent Document 3, the range of operation start cooling water temperature when energized and de-energized is smaller than when no heat transfer pipe is provided, and when the cooling water temperature is low, the lift There was a problem in that the amount could not be increased (see Figure 10). The reason for this is thought to be that in the absence of a heat transfer pipe, the wax itself would act as an insulating wall, preventing the heat generated by the heater from escaping into the cooling water.

In addition, heat transfer pipes (perforated metal pipes) have many holes drilled in them to pass the wax, but when the piston rod moves, the wax passes through the holes and the resistance force causes the wax to flow through the holes. There was a problem in that the joint at the end of the shape would open. Therefore, it was necessary to fix the joints of the heat transfer pipes by some means such as caulking.

Japanese Patent Application Publication No. 2005-155831 Japanese Patent Application Publication No. 2003-222072 Patent No. 6293955

Therefore, the present invention was devised to solve the above-mentioned problems, and its purpose is to efficiently use the heat generated by the heater to melt wax, and to make it possible to efficiently melt the wax while energizing and de-energizing. It is an object of the present invention to provide a wax thermoactuator that can set a high water temperature in the normal operation range and improve fuel efficiency because it can have a large difference in temperature at the start of operation (valve opening).

A wax thermoactuator according to a first aspect of the present invention is a wax thermoactuator comprising a housing in which wax is sealed and a piston rod that can be freely protruded and retracted into the housing, and has a heat generating means inside the piston rod. , the housing includes a cylindrical housing cup with a bottom that accommodates the wax, and the housing is loosely fitted onto the piston rod and heats the wax heated by the heating means. A heating heat transfer pipe is inserted into the housing cup, and the heat transfer pipe is made of a material having a predetermined thermal conductivity that is equal to or higher than the thermal conductivity of a metal material that is higher than the thermal conductivity of the wax. The heat transfer pipe has a cylindrical pipe main body, and an upper flange or a lower flange made of a heat insulating material formed on the outer periphery of the upper end or lower end of the pipe main body , and the heat transfer pipe is always connected to the upper flange or the lower flange. The pipe body is characterized in that the pipe body is separated from the inner circumferential surface of the housing cup by contacting the housing cup through the pipe body .

In the wax thermoactuator according to a second aspect of the invention, in the first aspect, an upper flange and a lower flange made of a heat insulating material are formed on the outer periphery of the upper end and lower end of the pipe main body of the heat transfer pipe, respectively. The heat transfer pipe is characterized in that the pipe main body is spaced apart from the inner peripheral surface of the housing cup by contacting the housing cup via the upper flange and the lower flange.

In the wax thermoactuator according to a third invention, in the second invention, the pipe main body of the heat transfer pipe is formed from a single plate material, and the joint thereof is continuous with the upper flange and the lower flange. It is characterized by being fixed with a heat insulating material.

In the wax thermoactuator according to a fourth aspect of the invention, in the third aspect, a large number of holes are bored in the circumferential surface of the pipe main body , and the heat insulating material that fixes the joints of the heat transfer pipes is It is characterized in that it is integrated into at least a portion of the hole of the main body .

In the wax thermoactuator according to a fifth aspect of the invention, in any one of the first to fourth aspects, the heat transfer pipe has the upper flange or the lower flange fixed by caulking the housing cup from the outside. and is positioned at a predetermined position within the housing cup.

A wax thermoactuator according to a sixth aspect of the present invention is the wax thermoactuator according to any one of the first to fifth aspects, in which the pipe body is made of a material having a thermal conductivity higher than a predetermined value so as not to restrict expansion or movement of the wax. It is characterized by having a large number of holes or being formed into a mesh shape.

According to the first to sixth inventions, the heat of the heater is prevented from escaping from the housing that is in direct contact with the heat transfer pipe, and the heat generated by the heater can be efficiently used to melt the wax. Therefore, according to the first to sixth inventions, it is possible to have a large difference in the operation start (valve opening) temperature between energized and de-energized states, so that the valve opening temperature for wax thermostats is normally set to the specification in the high temperature range. This allows the water temperature in the normal operation range to be set high. In other words, the engine cooling water can be heated to a high temperature. Therefore, according to the first to sixth inventions, it is possible to exhibit the effect of improving fuel efficiency by reducing friction within the engine.

In particular, according to the second invention, the upper and lower flanges made of a heat insulating material are formed on the outer peripheries of the upper and lower ends of the heat transfer pipe, respectively, so that even when the piston rod is operated, the heat transfer pipe It is possible to reliably prevent the housing cup from tilting and coming into contact with the housing cup and radiating heat from there. Therefore, according to the second aspect of the invention, a high lift amount can be ensured in a low temperature range (a range where the temperature of the cooling water is low and the wax does not melt), and the temperature of the engine cooling water can be increased.

In particular, according to the third invention, since the joint of the heat transfer pipe is fixed with an integral resin that is continuous with the upper flange and the lower flange, the heat transfer pipe is prevented from opening even when the piston rod is operated. This eliminates the need for caulking and fixing the ends of the heat transfer pipes and the need for members for positioning the heat transfer pipes.

In particular, according to the fourth aspect of the invention, even when the piston rod is operated, the resin that has entered some of the many holes can resist the resistance force when the wax passes through the many holes formed in the heat transfer pipe. It can be hung, and the joints of the heat transfer pipes can be reliably prevented from opening.

In particular, according to the fifth invention, positioning and fixing of the heat transfer pipe can be achieved by simply caulking from the outside of the housing cup, and the heat transfer pipe can be positioned at the axial center position of the housing cup, which was previously necessary. It is possible to reduce the number of jigs and work required. Therefore, according to the fifth invention, it is possible to eliminate the fear that the heat transfer pipe will rise or tilt, and it is also possible to reduce the unit price of the product.

FIG. 1 is a vertical sectional view showing a wax thermoactuator according to an embodiment of the present invention. FIG. 2 is a perspective view showing the wax thermoactuator same as above. FIG. 3 is a vertical cross-sectional view showing only the housing of the wax thermoactuator described above. FIG. 4 is a perspective view showing only the piston rod of the wax thermoactuator. FIG. 5 is a vertical sectional view showing only the piston rod same as above. FIG. 6 is a perspective view showing the wax thermoactuator shown above before the heat transfer pipe is integrally molded with resin. FIG. 7 is a perspective view showing a state in which the heat transfer pipe same as the above is integrally molded with resin. FIG. 8 is an enlarged view of section A in FIG. FIG. 9 is an enlarged view of part B in FIG. FIG. 10 is a graph of measurement results comparing the performance of the wax thermoactuator according to this embodiment and a conventional product by plotting the relationship between temperature and lift amount.

Hereinafter, a wax thermoactuator according to an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a vertical sectional view showing a wax thermoactuator 1 according to an embodiment of the present invention, and FIG. 2 is a perspective view showing the wax thermoactuator 1. Here, the wax thermoactuator refers to a temperature-sensitive control device called a wax element, thermopellet, or thermoelement that has both the functions of a temperature sensor and an actuator that performs control operations.

For example, a wax thermoactuator is used as an electronically controlled actuator that performs variable water temperature control in a cooling water temperature control system that variably controls the cooling water temperature of an internal combustion engine used in an automobile or the like. The wax thermoactuator's main uses are built into the carburetor or throttle chamber to release the fast idle auto choke function, and for motorcycle auto starters.

As shown in FIGS. 1 and 2, the wax thermoactuator 1 includes a housing 2 in which wax W is sealed, a piston rod 3 that can freely protrude and retract into the housing 2, and a piston rod 3 that is loosely fitted into the piston rod 3. This temperature-sensitive control device includes a cylindrical heat transfer pipe 4, a lid 5 that hermetically seals the upper part of the housing 2, and the like.

This wax thermoactuator 1 is provided with an electric heater 32 inside the piston rod 3, as will be described later. In other words, the wax thermoactuator 1 is a wax thermoactuator equipped with an electric heater that allows the piston rod 3 to project even in a low temperature environment where the wax W does not undergo sufficient thermal expansion.

In this embodiment, the wax W used in the wax thermoactuator 1 is paraffin wax that is solid at room temperature. This paraffin wax is a type of hydrocarbon compound, and refers to a long alkane having 20 or more carbon atoms.

Of course, the substance that can be sealed in the housing 2 of the wax thermoactuator 1 is not limited to paraffin wax, and any substance that has predetermined thermal expansion characteristics with a relatively large change in volume, such as microwax, can be applied to the present invention. It is. Further, depending on the combination, the wax according to the present invention is solid in a temperature range lower than room temperature, and waxes that are solid or liquid at room temperature can be appropriately applied depending on the use of the wax thermoactuator.

<Housing>
The housing 2 is a metal container made of brass that constitutes the wax thermoactuator 1, and is mainly composed of a housing cup 20 that accommodates the wax W. Furthermore, it goes without saying that the housing 2 may be constructed from a plurality of members, with the housing cup 20 and the housing cap being separate bodies, as described in Patent Document 3.

(housing cup)
FIG. 3 is a vertical sectional view showing only the housing cup 20 of the housing 2 before the upper end is rounded. As shown in FIGS. 1 to 3, the housing cup 20 includes a cup main body 20a serving as a container for accommodating the wax W, an enlarged diameter portion 20b formed above the cup main body 20a, and a diameter enlarged portion 20b formed above the cup main body 20a. The sealing portion 20c is formed above the sealing portion 20b.

The cup main body 20a is a vertically elongated bottomed cylindrical portion with an outer diameter of 12.5 mm, an inner diameter of about 8.0 mm, and a length of about 31 mm with the longitudinal direction (axial direction) taken in the vertical direction in the drawing. The inside thereof is a space for accommodating the wax W and the heat transfer pipe 4.

As shown in FIG. 3, the enlarged diameter part 20b is a part whose inner and outer diameters are larger than those of the cup body part 20a, with an outer diameter of 13.0 mm and an inner diameter of about 9.0 mm. This is a portion that accommodates the upper flange 41 of the pipe 4, as well as the rubber packing 35 and washer 36 of the piston rod 3.

As shown in FIG. 3, the sealing part 20c has an outer diameter of 17.5 mm and an inner diameter of about 13.5 mm before processing, which is a part whose inner and outer diameters are further enlarged than those of the enlarged diameter part 20b. It has a function of closing and sealing the upper end of the housing 2 by rounding the upper end in a state where the lid body 5 is fitted (see also FIG. 1).

<Piston rod>
4 is a perspective view showing only the piston rod 3, and FIG. 5 is a vertical sectional view showing only the piston rod 3. As shown in FIGS. 4 and 5, the piston rod 3 includes a bottomed cylindrical rod body 30 with an outer diameter of 4 mm whose lower end is closed, and a ring-shaped rod body 30 fixed to the upper part of the rod body 30 on the axis. It is a stainless steel member mainly composed of a flange 31. When the piston rod 3 protrudes or retreats relative to the housing 2, it presses another member (not shown) to drive the housing 2 and the valve integrated with the housing 2, thereby driving the flow path. It has the function of opening and closing.

(Electric heater: heat generation means)
Inside the rod body 30, an electric heater 32 is provided as a heat generating means (heat source) that generates heat when energized. The electric heater 32 according to this embodiment is electrically connected to a 12V DC power source such as a car battery through wirings 33 and 34. The electric heater 32 has a function of generating heat when energized and allowing the wax W to thermally expand, regardless of the temperature environment around the wax thermoactuator 1. Of course, the heat generating means according to the present invention may be connected to an AC power supply, and is not limited to an electric heater, but may be any heat generating means whose start and end of heat generation can be controlled by operating a switch or the like.

(Rubber packing and washer)
Further, as shown in FIGS. 4 and 5, a donut-shaped rubber packing 35 and a washer 36 are fitted around the rod body 30 of the piston rod 3. Therefore, the rubber packing 35 and the washer 36 allow the piston rod 3 to move upward and downward, and also seal the gap between the piston rod 3 and the wax thermoactuator 1. It is possible to reliably prevent the wax W from flowing into the interior or leaking out.

<Heat transfer pipe>
Next, the heat transfer pipe 4 according to this embodiment will be explained using FIGS. 6 and 7. FIG. 6 is a perspective view showing a single heat transfer pipe 4 made of a copper plate according to this embodiment, and FIG. It is a perspective view which shows the state which solidified 40b with resin. The heat transfer pipe 4 according to the present embodiment has a generally cylindrical shape made of a rectangular copper plate with a thickness of about 0.2 mm that preferentially transfers the heat of the electric heater 32 in the axial direction of the housing 2. It is a member of

The reason why the heat transfer pipe 4 is made of copper is to make the heat conductivity sufficiently higher than that of the wax W and to preferentially transfer heat in the axial direction of the housing. The thermal conductivity of copper is 391 [W/m·K], which is significantly higher than the thermal conductivity of wax W, which is 0.25 [W/m·K]. Of course, the heat transfer pipe according to the present invention may be made of other materials with higher thermal conductivity than wax W, such as carbon or metals other than copper (e.g., aluminum, gold, silver). Needless to say.

For example, the thermal conductivity of brass used for the housing cup 20 etc. is 117 [W/m・K], and the thermal conductivity of stainless steel used for the piston rod 3 is 16.3 [W/m・K]. (100°C). On the other hand, the thermal conductivity of the resin used for the upper flange 41, lower flange 42, etc. of the heat transfer pipe 4, which will be described later, is 0.3 [W/m·K], and the thermal conductivity of the resin used for the rubber packing 35 is 0.3 [W/m·K]. The thermal conductivity is 0.25 [W/m·K].

In short, the heat transfer pipe according to the present invention is not limited to copper, but has good thermal conductivity such as metal or carbon (for example, the thermal conductivity is significantly higher than that of wax W, which is 0.25 [W/m・K]). , and a predetermined value that is comparable to the thermal conductivity of readily available metal materials (for example, as mentioned above, the thermal conductivity of stainless steel is 16.3 [W/m・K] (100 ° C.)). 15.0 [W/m·K] or more) and has a large number of holes or has a mesh shape so that the wax W can move. Here, the term "mesh-like" includes a mesh-like structure in which vertical and horizontal fibers are woven and not welded.

(Pipe body)
First, the pipe body 40 of the heat transfer pipe 4 will be explained. As shown in FIG. 6, the heat transfer pipe 4 according to the present embodiment is manufactured by rolling the ends of a rectangular copper plate into a cylindrical shape to form a pipe body 40, and then, as shown in FIG. 41, a lower flange 42, a connecting portion 43, etc. are molded from the same resin and are integrated into a resin-integrated heat transfer pipe.

The length H1 of the pipe main body 40 shown in FIG. 6 is set to approximately 30.0 mm to 31.5 mm. As shown in FIG. 1, this length is approximately the same length as approximately the entire internal length in the longitudinal direction of the housing 2 from the inner bottom surface of the housing cup 20 to the vicinity of the lower end of the rubber packing 35. By setting the length H1 of the heat transfer pipe 4 in this way, the movement (rise) of the piston rod 3 ensures that the heat is transferred to the wax W near the bottom of the housing cup 20, which is the farthest distance from the electric heater 32. Heat can be transferred through the heat pipe 4.

The outer diameter D1 of the pipe body 40 is preferably set to about 5.0 mm to 6.0 mm, and in this embodiment, the outer diameter is set to about 5.0 mm. This is because the outer diameter D1 of the heat transfer pipe 4 is smaller than the inner diameter (about 8.0 mm) of the housing cup 20, and the inner diameter D2 of the heat transfer pipe 4 (D1 - thickness 0.2 mm x 2 = about 4.6 mm). is set to be larger than the outer diameter of the piston rod 3 (about 4 mm).

Thereby, the heat transfer pipe 4 can be spaced apart from the inner circumferential surface of the housing cup 20 and not inscribed in the piston rod 3. Therefore, wax W with low thermal conductivity exists between the heat transfer pipe 4 and the inner peripheral surface of the housing cup 20, and it is possible to prevent the heat of the electric heater 32 from escaping from the housing 2 to the outside. .

Moreover, since the heat transfer pipe 4 is not inscribed in the piston rod 3, it is possible to prevent the heat transfer pipe 4 from interfering with the protruding and retracting motion of the piston rod 3. Therefore, the thermal expansion of the wax W can be efficiently converted into a protruding operation (lifting operation) of the piston rod 3.

As shown in FIG. 6, a large number of holes 40a having a small diameter of about 0.3 mm are bored in the circumferential surface of the pipe body 40. These many holes 40a are holes for allowing the wax W present inside the heat transfer pipe 4 to pass through the heat transfer pipe 4 when it thermally expands or contracts.

(Top flange and bottom flange)
Further, as shown in FIG. 7, a donut-shaped (ring-shaped) upper flange 41 and a lower flange 42 made of resin, which are heat insulating materials, are formed on the outer peripheries of the upper and lower ends of the heat transfer pipe 4, respectively. As shown in FIGS. 8 and 9, the heat transfer pipe 4 is configured to come into contact with the housing cup 20 via an upper flange 41 and a lower flange 42, which are heat insulating materials.

That is, as shown in FIG. 7, the heat transfer pipe 4 includes a cylindrical pipe body 40 made of a copper plate, and a brim-shaped upper flange that protrudes outward from the outer peripheral surface of the upper and lower ends of the pipe body 40. 41 and a lower flange 42. Here, the upper flange 41 and the lower flange 42 are not limited to the illustrated donut shape (ring shape) that continuously extends outward from the outer circumferential surface of the pipe body 40 over the entire circumference, but may be a pair of left and right bar-shaped protrusions. A plurality of objects or a plurality of radially protruding objects may be shaped to protrude outward from the outer circumferential surface of the pipe main body 40 in a flange-like manner.

In this way, since the flange 41 and the lower flange 42 made of a heat insulating material are interposed, as shown in FIGS. The structure is such that it does not come into direct contact with the housing cup 20 and is always interposed through an insulating material such as resin, rubber, or ceramics having a low thermal conductivity of about 0.3 [W/m·K]. Therefore, there is a part where the heat transfer pipe and the cup come into contact, which was a problem with the wax thermoactuator described in Patent Document 3, and heat is dissipated from there, so the range of the cooling water temperature at the start of operation when energized and when not energized is becomes smaller, which solves the problem of not being able to increase the amount of lift when the cooling water temperature is low.

Further, as shown in FIGS. 1, 2, and 9, the outer circumferential surface of the housing cup 20 is caulked from the outside, so that a plurality of rectangular recesses 20d (four in the illustrated embodiment) are evenly formed. At 20d, the lower flange 42 of the heat transfer pipe 4 is positioned and fixed at a predetermined position within the housing cup 20. For this reason, the axial center of the heat transfer pipe 4, which was required in the past, is made to coincide with the axial center of the housing cup 20, and the distance between the housing cup 20 and the heat transfer pipe 4 is made equal, so that the wax etc. is not biased. This eliminates the need for a jig for positioning. Moreover, the labor and effort required for this positioning work can be reduced.

Of course, the upper flange 41 of the heat transfer pipe 4 may be fixed by caulking the upper part of the housing cup 20 (directly below the expanded diameter part 20b) to form a recess. Even in that case, the axial center of the heat transfer pipe 4 can be made to coincide with the axial center of the housing cup 20, so that the distance between the housing cup 20 and the heat transfer pipe 4 can be equalized.

(Connection part and flange connection part)
The joint 40b at the end of the copper plate of the pipe body 40 shown in FIG. 6 is solidified with resin and integrated, as shown in FIG. 43 is formed. In addition, like the connecting portion 43, three flange connecting portions 44 connecting the upper flange 41 and the lower flange 42 are formed.

The relationship between the connecting portion 43 and the flange connecting portion 44 is such that the center lines are approximately equally spaced along the outer peripheral surface of the pipe body 40, and the connecting portion 43 is formed at the joint 40b of the steel plate of the pipe body 40. Three flange connecting portions 44 are formed on the remaining three sides.

The connecting portion 43 is formed along the joint 40b of the pipe main body 40 shown in FIG. 6, and is integrally formed by spanning the hole 40a on both sides thereof and entering the hole 40a. There is. Therefore, the wax W passes through the holes 40a and expands the joints 40b of the pipe body 40, but the resin that has entered some of the holes 40a can hold the heat transfer pipe 4. It is possible to reliably prevent the joint 40b from opening.

Moreover, the aforementioned donut-shaped (ring-shaped) upper flange 41 and lower flange 42 also have the effect of preventing the joint 40b of the heat transfer pipe 4 from opening.

The flange connecting portion 44 cooperates with the connecting portion 43 to connect the upper flange 41 and the lower flange 42 at equal intervals, thereby pushing the uneven pipe body 40 that acts when the wax W passes through the hole 40a. It has the function of countering the expanding force. Therefore, the flange communication portion 44 does not necessarily need to fit into some of the many holes 40a.

<Lid body>
The lid body 5 is a member made of metal, and, as shown in FIG. 1, has a circular rod hole 50 that opens upward and downward, through which the piston rod 3 is inserted. The lid body 5 cooperates with the rubber packing 35 and the washer 36 to allow the piston rod 3 to move upward and downward, and also seals the gap between the piston rod 3 and the area around the wax thermoactuator 1. It has a function of preventing the fluid from flowing into the housing 2 and preventing the wax W from leaking out.

[Comparative measurement results]
Next, with reference to FIG. 10, measurement results comparing the performance of the wax thermoactuator 1 according to the present embodiment and a conventional product will be described. FIG. 10 is a graph of measurement results comparing the performance of the wax thermoactuator 1 according to this embodiment and a conventional product by plotting the relationship between temperature and lift amount. Here, "without heat transfer pipe" refers to a conventional wax thermoactuator without a heat transfer pipe, and is indicated by ▲-▲. In addition, "with heat transfer pipe" refers to the wax thermoactuator shown in Patent Document 3, and is indicated by ■-■. The resin-integrated heat transfer pipe refers to the wax thermoactuator 1 according to the present embodiment, and is indicated by ●-●.

The graph in FIG. 10 shows the case where the electric heater 32 is energized by applying a DC voltage of 12 V (when 12 V is applied) for all cases without a heat transfer pipe, with a heat transfer pipe, and with a resin-integrated heat transfer pipe. The case where wax W is thermally expanded without energization (when energization is not applied) is shown by the broken line of 〇-〇.

As shown in FIG. 10, in either case, there is almost no difference when no current is applied, but there is a clear difference when 12V is applied. In other words, it can be seen that the presence of the heat transfer pipe can increase the lift amount in the temperature range near the wax melting point (wax is a solid body region) compared to the case without the heat transfer pipe. On the other hand, it can be seen that the lift amount with the heat transfer pipe is lower than before the heat transfer pipe was installed in the low temperature range (where the wax is solid) compared to the case without the heat transfer pipe. This is thought to be because, as mentioned above, there is a portion where the heat transfer pipe and the housing cup come into contact, and heat is radiated from there.

On the other hand, it can be seen that the resin-integrated heat transfer pipe, which is the wax thermoactuator 1 according to the present embodiment, has an increased lift amount in all temperature regions. In other words, it was confirmed that the wax thermoactuator 1 according to the present embodiment can achieve a high lift amount not only in the low temperature range (where the wax is solid) but also in all temperature ranges.

In the wax thermoactuator 1 described above, the portion that contacts the housing 2 is covered with a heat insulating material such as a resin having low thermal conductivity. Therefore, according to the wax thermoactuator 1, the heat of the electric heater 32 is prevented from escaping from the housing 2, and a high lift amount is achieved not only in the low temperature range (where the wax is solid) but also in all temperature ranges. be able to. Therefore, according to the wax thermoactuator 1, the valve opening temperature as a normal wax thermostat can be specified in a high temperature range, and the engine cooling water can be heated to a high water temperature. Therefore, the effect of improving fuel efficiency can be achieved by reducing friction within the engine.

Further, in the wax thermoactuator 1, a brim-shaped upper flange 41 and a lower flange 42 made of a heat insulating material are formed on the upper and lower sides of the heat transfer pipe 4, respectively. Therefore, the wax thermoactuator 1 can reliably prevent the heat transfer pipe 4 from tilting and coming into contact with the housing cup 20 and radiating heat therefrom even when the piston rod 3 is operated.

In the wax thermoactuator 1, the joint 40b of the heat transfer pipe 4 is fixed to the upper flange 41 and the lower flange 42 at a connecting portion 43 that is continuous with the upper flange 41 and the lower flange 42, so that the wax thermoactuator 1 is integrated. Therefore, according to the wax thermoactuator 1, the heat transfer pipe 4 can be prevented from opening even when the piston rod 3 is operated, and the joint 40b at the end of the heat transfer pipe 4 is fixed by caulking. The effort and members for positioning the heat transfer pipe 4 can be omitted.

In addition, in the wax thermoactuator 1, a connecting part 43 is formed along the joint 40b, and is integrally formed by spanning the hole 40a on both sides of the connecting part 43 and entering the hole 40a. . Therefore, according to the wax thermoactuator 1, even against the resistance force when the wax W passes through the many holes 40a formed in the heat transfer pipe 4, the resin that has entered some of the many holes 40a It can be latched, and the joint 40b of the heat transfer pipe 4 can be reliably prevented from opening.

Further, in the wax thermoactuator 1, a plurality of rectangular recesses 20d are evenly formed on the outer peripheral surface of the housing cup 20, and the lower flange 42 of the heat transfer pipe 4 is positioned at a predetermined position within the housing cup 20 by the recesses 20d. It has been fixed. Therefore, according to the wax thermoactuator 1, the axial center of the heat transfer pipe 4, which was required in the past, is made to coincide with the axial center of the housing cup 20, and the distance between the housing cup 20 and the heat transfer pipe 4 is made equal. This eliminates the need for a positioning jig to prevent the wax, etc. from becoming uneven. Moreover, the labor and effort required for this positioning work can be reduced.

The wax thermoactuator 1 according to the embodiment of the present invention has been described in detail above, but the embodiments described above or shown in the drawings are merely embodiments that have been realized in carrying out the present invention. . Therefore, the technical scope of the present invention should not be construed as being limited by these.

In particular, the lift amount refers to the protruding length of the piston rod when the housing of the wax thermoactuator is fixed and the piston rod is moved up and down. Therefore, depending on the use of the wax thermoactuator and how it is fixed, it is necessary to read the above-mentioned lift amount as the protrusion length of the piston rod. Further, the upper flange and the lower flange may be made of any heat insulating material that has a thermal conductivity lower than that of the heat transfer pipe, and is not limited to resin, but may also be made of a rubber material made of a rubber elastic body or a material made of ceramics.

1: Wax thermoactuator 2: Housing 20: Housing cup 20a: Cup body portion 20b: Expanded diameter portion 20c: Sealing portion 20d: Recessed portion 3: Piston rod 30: Rod body 31: Flange 32: Electric heater (heating means)
33, 34: Wiring 35: Rubber packing 36: Washer 4: Heat transfer pipe 40: Pipe body 40a: Hole 40b: Joint 41: Upper flange 42: Lower flange 43: Connection portion 44: Flange connection portion 5: Lid body 50 : Rod hole W: Wax

Claims (6)

A wax thermoactuator comprising a housing in which wax is sealed and a piston rod that can be freely protruded and retracted into the housing, the piston rod having a heat generating means inside the wax thermoactuator,
The housing includes a cylindrical housing cup with a bottom that accommodates the wax,
A heat transfer pipe is inserted into the housing cup and is loosely fitted to the piston rod and transmits heat in the axial direction of the housing to the wax that is separated from the wax that is heated by the heat generating means,
The heat transfer pipe includes a cylindrical pipe body made of a material with a predetermined thermal conductivity that is equal to or higher than the thermal conductivity of a metal material that is higher than the thermal conductivity of the wax, and an upper end or a lower end of the pipe body. The heat transfer pipe has an upper flange or a lower flange made of a heat insulating material formed on the outer periphery of the pipe , and the heat transfer pipe always comes into contact with the housing cup via the upper flange or the lower flange , so that the pipe body A wax thermoactuator characterized by being configured to be spaced apart from the inner peripheral surface of a housing cup . An upper flange and a lower flange made of a heat insulating material are formed on the outer periphery of the upper end and lower end of the pipe main body of the heat transfer pipe, respectively, and the heat transfer pipe The wax thermoactuator according to claim 1, wherein the pipe main body is separated from the inner peripheral surface of the housing cup by contacting the housing cup. Claim 2, wherein the pipe body of the heat transfer pipe is formed from a single plate, and the joint thereof is fixed with an integral heat insulating material that is continuous with the upper flange and the lower flange. The wax thermoactuator described in . A large number of holes are bored on the circumferential surface of the pipe body ,
4. The wax thermoactuator according to claim 3, wherein the heat insulating material that fixes the joint of the heat transfer pipe is integrated into at least a portion of the hole of the pipe body . Claims 1 to 4, wherein the heat transfer pipe is positioned at a predetermined position within the housing cup with the upper flange or the lower flange fixed by caulking the housing cup from the outside. The wax thermoactuator according to any of the above. A claim characterized in that the pipe body is made of a material with a thermal conductivity higher than a predetermined value, and has a large number of holes or is formed in a mesh shape so as not to restrict expansion or movement of the wax. 6. The wax thermoactuator according to any one of 1 to 5.

Images