KR102490772B1 - Thrmostat for vehicle - Google Patents

Abstract

A thermostat for a vehicle that opens a coolant passage or a bypass passage of an engine according to the temperature of the coolant. A vehicle thermostat is a vehicle thermostat filled with wax that expands or contracts according to the temperature of the coolant, comprising: a piston reciprocating by expansion or contraction of the wax; a backup plate disposed between the wax and the piston and having one surface in contact with the piston; a rubber piston disposed between the wax and the piston and having one surface in contact with the backup plate; and a guide part that surrounds the piston, the backup plate, and the rubber piston and guides the vertical movement according to the expansion or contraction of the wax, wherein the coolant can flow between the backup plate and the guide part. Gaps may form.

Description

Thermostat for vehicles {THRMOSTAT FOR VEHICLE}

The present invention relates to a vehicle thermostat for maintaining the temperature of the cooling water at a constant temperature by opening and closing a cooling water passage or a bypass passage according to a change in the temperature of the cooling water, and more particularly, to a vehicle in which the cooling water is discharged between a backup plate and a guide unit. The present invention relates to a thermostat for a vehicle capable of preventing premature opening and closing of a valve by forming a space therefor.

In general, the cooling system of a vehicle circulates coolant only inside the engine during preheating to maintain the engine at an appropriate temperature, and when a certain temperature is reached, the coolant is circulated to the radiator to cool and then flows back into the engine to prevent overheating of the engine. serves to prevent

In such a cooling system, a bypass pipe through which coolant circulates and a pipe through which a radiator and a water pump circulate are installed, and a thermostat for determining circulation of coolant between the bypass pipe and the radiator is installed at an appropriate position in the pipe.

Specifically, as shown in FIG. 1, a conventional thermostat 1 is installed in a housing 11 selectively communicating with a cooling water passage and a bypass passage, and is installed in the housing 11 and expands or contracts according to the temperature of the cooling water. The wax case 16 filled with the wax W therein, the guide portion 15 coupled to the lower portion of the wax case 16, and the expansion or contraction of the wax W within the guide portion 15. The main valve 18 for opening and closing the cooling water flow path and the bypass flow path, elastically supported in the housing 11 and formed in a form surrounding the piston 12 moving up and down, the guide part 15, and the piston 12 moving in the vertical direction by the ) and a valve guide part 17 having a bypass valve 19.

Accordingly, when the temperature of the cooling water exceeds a certain value, the wax W expands, and the piston 12 and the valve guide part 17 move downward due to the expansive force of the wax W. Then, since the main valve 18 opens the cooling water passage and the bypass valve 19 blocks the bypass passage, the coolant flows into the thermostat 1, and the coolant flowing into the thermostat 1 may flow into the radiator via the engine.

However, in the prior art, when the thermostat 1 is driven, the backup plate 13 expands or contracts due to the thermal expansion rate of the backup plate 13, and coolant (C) is formed between the backup plate 13 and the rubber piston 14. There was a problem with adhesion.

In this way, when the coolant C adheres between the backup plate 13 and the rubber piston 14 inside the guide part 15, the piston 12 descends in advance by the amount of the adhered coolant C. , the main valve 18 may be opened at a temperature lower than the predetermined temperature. That is, since the main valve 18 is opened at a temperature lower than the predetermined opening and closing temperature, the cooling efficiency is lowered, which affects the operation of the vehicle and threatens the driver's safety.

Registered Patent Publication 10-2116256 (Announced on June 2, 2020)

An object of the present invention is to provide a vehicle thermostat capable of controlling the valve at a desired opening/closing temperature without early opening of the valve at a temperature lower than a predetermined temperature by forming a space through which coolant can be discharged between a backup plate and a valve guide unit. is in providing

A vehicle thermostat according to the present invention for achieving the above object is a vehicle thermostat filled with wax that expands or contracts according to the temperature of the coolant, comprising: a piston reciprocating by expansion or contraction of the wax; a backup plate disposed between the wax and the piston and having one surface in contact with the piston; a rubber piston disposed between the wax and the piston and having one surface in contact with the backup plate; and a guide part that surrounds the piston, the backup plate, and the rubber piston and guides the vertical movement according to the expansion or contraction of the wax, wherein the coolant can flow between the backup plate and the guide part. Gaps may form.

Also, an outer diameter of the backup plate may be smaller than an inner diameter of the guide part.

In addition, the backup plate contracts or expands according to the temperature of the cooling water, and even when the temperature of the cooling water reaches a maximum value and the backup plate expands to the maximum, the cooling water continues to flow between the backup plate and the guide part. gaps may be formed.

In addition, one surface of the rubber piston may contact the backup plate, and an edge of a surface of the rubber piston contacting the backup plate may be formed as a curved surface.

In addition, the valve guide portion formed in a form surrounding the guide portion and the piston is elastically supported in the housing and includes a main valve and a bypass valve for opening and closing the coolant flow path and the bypass flow path, and the wax may be formed by mixing high-temperature molten paraffin having, as a melting point, a first temperature at which the main valve opens, and low-temperature molten paraffin having, as a melting point, a second temperature lower than the first temperature.

In addition, when the temperature of the cooling water is greater than the second temperature and less than the first temperature, the cooling water introduced into the space between the rubber piston and the backup plate due to the expansion of the wax is discharged to the outside of the space. and the main valve may be provided so as not to open yet.

A vehicle thermostat according to the present invention includes a housing that selectively communicates with a cooling water passage and a bypass passage of a vehicle; a wax case disposed in the housing and filled with wax that expands or contracts according to the temperature of the cooling water; a guide unit coupled to a lower portion of the wax case; a piston disposed within the guide unit and reciprocating by expansion or contraction of the wax; a backup plate inserted into the guide unit, disposed between the wax and the piston, and having one surface in contact with the piston; a rubber piston inserted into the guide unit, disposed between the wax and the piston, and having one surface in contact with the backup plate; and a valve guide part configured to surround the guide part and the piston, elastically supported in the housing, and including a main valve and a bypass valve for opening and closing the cooling water passage and the bypass passage. The plate may be coupled to the inside of the guide unit, while not sealing the inside of the guide unit.

According to the present invention, it is possible to prevent the coolant from adhering between the backup plate and the rubber piston by forming a gap through which the coolant flows between the backup plate and the guide part. Accordingly, it is possible to prevent the piston from being pushed and moved upward by an amount to which the coolant has adhered, and thus, premature opening and closing of the valve at a temperature lower than a preset temperature can be prevented.

In addition, since the main valve and the bypass valve can be controlled at a desired opening/closing temperature, the cooling efficiency of the cooling water and the reliability of the product can be improved.

1 is a cross-sectional view of a vehicle thermostat according to the prior art.
2 is a cross-sectional view of a vehicle thermostat according to an embodiment of the present invention.
3 is a perspective view showing a lower part of the rubber piston shown in FIG. 2;
4 is a view showing a state in which a vehicle thermostat according to an embodiment of the present invention is installed in an engine.
5 is a graph showing the lift of the wax according to the contents of high-temperature melting paraffin and low-temperature melting paraffin included in the wax of the present invention.

Hereinafter, a vehicle thermostat according to a preferred embodiment will be described in detail with reference to the accompanying drawings. Here, the same reference numerals are used for the same components, and repeated descriptions and detailed descriptions of known functions and configurations that may unnecessarily obscure the subject matter of the invention are omitted. Embodiments of the invention are provided to more completely explain the present invention to those skilled in the art. Accordingly, the shapes and sizes of elements in the drawings may be exaggerated for clarity.

2 is a cross-sectional view of a vehicle thermostat according to an embodiment of the present invention, FIG. 3 is a perspective view showing a lower portion of the rubber piston shown in FIG. 2, and FIG. 4 is a vehicle thermostat according to an embodiment of the present invention. It is a drawing showing the state installed on the engine.

2 to 4, the vehicle thermostat 100 is filled with wax W that expands or contracts according to the coolant temperature, and includes a housing 110, a wax case 120, and a guide. A portion 130 , a piston 140 , a backup plate 150 , and a rubber piston 160 may be included.

Here, the vehicle thermostat 100 is installed between the engine and the radiator to selectively open the coolant flow path 10 or the bypass flow path 20 according to the temperature change of the coolant. ) can be used to maintain the cooling water in a certain temperature range by adjusting the flow rate.

Although shown as being applied to an electric thermostat in this embodiment, it may be applied to a mechanical thermostat. Further, in the present embodiment, description will be made based on a state in which the main valve 171 is closed and the bypass valve 172 is open, that is, a state in which cooling water circulates through the bypass passage 20 .

The housing 110 may be connected to a flow path through which cooling water of an automobile engine flows. Specifically, the housing 110 receives cooling water from the water pump W/P of the engine ENG through the supply channel 30, and the cooling water channel 10 for receiving the cooling water from the radiator RAD; Bypass passages 20 through which coolant discharged from the engine ENG is bypassed may be installed at points where they cross each other, and may be selectively communicated with the coolant passage 10 and the bypass passage 20 .

The housing 110 may have an accommodation space formed therein so that various components constituting the vehicle thermostat 100 may be installed therein, and upper and lower coolant through holes 110a and lower coolant through holes 110b, respectively. can be formed. Here, the upper cooling water through-hole 110a may communicate with the cooling water passage 10 and the lower cooling water through-hole 110b may communicate with the bypass passage 20 .

Specifically, the housing 110 may selectively communicate with the coolant passage 10 and the bypass passage 20 of the vehicle depending on whether the main valve 171 or the bypass valve 172 is opened or closed. Accordingly, when the main valve 171 is opened, the upper cooling water passage 110a communicates with the cooling water passage 10 to control the flow of cooling water passing through the cooling water passage 10 and the bypass valve 172 opens. In this case, the lower coolant passage 110b communicates with the bypass passage 20 so that the flow of coolant passing through the bypass passage 20 can be controlled.

The wax case 120 is disposed within the housing 110, and wax W, which expands or contracts according to the temperature of the cooling water, may be filled therein. For example, when the temperature of the cooling water circulating in the bypass passage 20 rises or falls, the temperature of the wax case 120 and the wax W may also rise or fall due to heat conduction, and the wax W This temperature change can cause the volume to increase or decrease, causing it to expand or contract.

In other words, when the temperature of the cooling water circulating through the bypass passage 20 is higher than a certain value, the wax (W) expands, and when the temperature of the cooling water is lower than a certain value, the wax (W) contracts. At this time, in order to prevent the wax (W) from overflowing from the wax (W) case, a diaphragm 121 that is deformed as the wax (W) expands or contracts may be installed in the wax case 120 .

Meanwhile, a heater H may be installed inside the wax case 120 to heat the wax W according to a driving environment such as a vehicle load condition. However, the present invention is not limited to the electrical type and can be applied to the mechanical type.

The guide part 130 is configured to surround the piston 140, the backup plate 150, and the rubber piston 160 to be described later, and allows the guide part 130 to move up and down according to the expansion or contraction of the wax W. can An auxiliary seal cap 180 may be provided below the guide part 130 to prevent coolant from flowing into the piston 140 .

For example, the guide part 130 may be formed in the shape of a hollow cylinder with open top and bottom, and an upper part may be coupled to the lower part of the wax case 120 . In addition, the guide portion 130 may be formed of brass or SUS material having good thermal conductivity, and may be provided to have a thermal expansion coefficient of about 19 x 10 ^-6 /°C.

The piston 140 may be disposed within the guide part 130 and may reciprocate by expansion or contraction of the wax (W). For example, the piston 140 may be disposed at the lowermost side of the guide part 130, and according to the change in the volume of the wax W, the back-up plate 150, the rubber piston 160, and the semi-fluid By means of 122, it can reciprocate in the vertical direction on the drawing.

The backup plate 150 is disposed between the wax W and the piston 140, and one surface may contact the piston 140. For example, the backup plate 150 may be inserted into the guide part 130 and disposed between the wax W and the piston 140, and the lower side may be disposed in contact with the upper portion of the piston 140. can

The backup plate 150 may be formed of a material that is easy to process and has good durability. For example, the backup plate 150 may be made of a material selected from a mixture of PTFE (Polytetrafluoroethylene) and carbon, PTFE, graphite, bronze, and carbon fiber. , but is not limited to these materials. The backup plate 150 may be formed to have a thermal expansion rate of about 5 x 10 ^-5 /°C.

As described above, cooling water may be introduced between the backup plate 150 and the guide part 130 due to thermal expansion of the backup plate 150 , and adhesion may occur between the backup plate 150 and the rubber piston 160 . Therefore, in order to prevent the adhesion of the cooling water, the back-up plate 150 may be coupled without sealing the inside of the guide part 130, which will be described in detail later.

The rubber piston 160 is for sealing between the wax W and the piston 140 by being in close contact with the guide 130 when the wax W expands, and is disposed between the wax W and the piston 140, One side may contact the backup plate 150 . For example, the rubber piston 160 may be formed of a flexible material such as rubber or silicon, and may be disposed in a form in which a lower surface contacts an upper portion of the backup plate 150 .

Meanwhile, an upper portion of the rubber piston 160 may be filled with a semi-fluid 122 that may contact the diaphragm 121 . The semi-fluid 122 is a material in an intermediate state between a liquid and a solid, and can move back and forth by the expansion or contraction of the wax (W).

The rubber piston 160 is in close contact with the lower part of the semi-fluid 122 to prevent the wax W and the anti-fluid 122 from leaking toward the piston 140, and is fitted in the guide part 130 in an interference manner. It is inserted and can be reciprocated in the up and down direction within the guide part 130 by the volume change of the wax (W).

According to the present invention, the valve guide portion 170 formed in a form surrounding the guide portion 130 and the piston 140 and elastically supported in the housing 110 may be further included. As the guide part 130 and the piston 140 are disposed inside the valve guide part 170 as described above, when the piston 140 moves downward and pressurizes the valve guide part 170, the valve guide part 170 also moves to the lower part. , and when the piston 140 moves upward, the valve guide part 170 may move upward due to the restoring force of the main valve elastic member 173 to be described later.

The valve guide part 170 may include a main valve 171 and a bypass valve 172 for opening and closing the cooling water passage 10 and the bypass passage 20 .

The main valve 171 may be fixed to an upper outer circumferential surface of the valve guide unit 170 and may open and close the coolant passage 10 as the valve guide unit 170 moves. As the main valve 171 is formed to open and close the coolant passage 10, the flow of coolant supplied to the radiator can be controlled.

For example, the main valve 171 may be elastically supported inside the housing 110 by the main valve elastic member 173, and may be installed between the upper coolant through hole 110a and the lower coolant through hole 110b so that the housing ( 110) can be partitioned vertically. In addition, the outer upper surface of the main valve 171 is formed to come into close contact with the stepped 111 formed inside the housing 110 to prevent the coolant discharged from the supply passage 30 from flowing into the coolant passage 10. can block

Accordingly, when the valve guide part 170 moves downward due to the expansion of the wax W, the main valve 171 in close contact with the step 111 of the housing 110 also moves downward, and the housing 110 and A space is formed between the main valve 171. That is, the cooling water passage 10 that was shielded by the main valve 171 is opened, and the cooling water can circulate through the cooling water passage 10 .

The bypass valve 172 may be fixed to a lower outer circumferential surface of the valve guide unit 170 , and the bypass passage 20 may be opened and closed by movement of the valve guide unit 170 . For example, the bypass valve 172 may be elastically supported by the valve guide part 170 by the bypass valve elastic member 174 .

The bypass valve 172 moves in the same direction as the main valve 171, but whether it is opened or closed may be reversed. For example, when the main valve 171 opens the cooling water passage 10, the bypass valve 172 blocks the bypass passage 20, and when the main valve 171 blocks the cooling water passage 10, the bypass valve 172 blocks the bypass passage 10. The valve 172 may be formed to open the bypass flow path 20 .

That is, when the wax (W) expands and the piston 140 and the valve guide part 170 move downward, the main valve 171 opens the cooling water passage 10 and the bypass valve 172 bypasses the The flow path 20 may be shielded. Accordingly, the cooling water may be supplied only to the radiator RAD through the cooling water flow path 10 to perform cooling.

Conversely, when the wax (W) contracts and the valve guide part 170 moves upward, the main valve 171 blocks the cooling water passage 10 and the bypass valve 172 closes the bypass passage 20. ) is opened. Accordingly, the cooling water may be circulated only within the engine ENG through the bypass flow path 20 .

According to the present invention, the outer diameter of the backup plate 150 is smaller than the inner diameter of the guide part 130, so that the coolant adhered between the backup plate 150 and the guide part 130 can flow toward the piston 140. A gap S may be formed. That is, by forming a flow path through the gap (S) between the backup plate 150 and the guide part 130, the coolant can be naturally introduced and discharged along the gap (S), so that the backup plate 150 It is possible to prevent the cooling water from adhering between the rubber piston 160 and the rubber piston 160 .

The backup plate 150 can contract or expand according to the temperature of the cooling water by the thermal expansion rate, and even when the temperature of the cooling water reaches the maximum value and the backup plate 150 expands to the maximum, the backup plate 150 and the guide A gap S through which cooling water may flow may be formed between the parts 130 .

That is, in the related art, when low-temperature cooling water flows into the housing 110, the backup plate 150 contracts according to the thermal expansion rate, and the cooling water moves between the guide part 130 and the backup plate 150 by this contraction force. entered into space. In this state, when the high-temperature coolant flows in, the backup plate 150 expands again, so that the coolant that has not escaped adheres between the backup plate 150 and the rubber piston 160, and the piston 140 is separated by the amount of the adhering coolant. ) is lowered in advance and the main valve 171 is opened at a temperature lower than the preset temperature, thereby reducing cooling efficiency.

However, according to the present invention, even when the temperature of the cooling water reaches the maximum value and the backup plate 150 expands to the maximum, there is a gap S through which the cooling water flows between the backup plate 150 and the guide part 130. By being implemented to be formed, the cooling water can be naturally introduced and discharged into the gap S between the guide part 130 and the backup plate 150 regardless of the thermal expansion rate of the backup plate 150 . Accordingly, since the adhesion between the backup plate 150 and the rubber piston 160 can be prevented as in the prior art, the main valve 171 and the bypass valve 172 can be controlled at a desired opening and closing temperature. Cooling efficiency and product reliability can be improved.

3 is a perspective view showing the lower part of the rubber piston 160, one surface of the rubber piston 160 is in contact with the backup plate 150, and the edge of the surface of the rubber piston 160 that is in contact with the backup plate 150 ( 161) may be formed as a curved surface.

For example, by forming the lower edge 161 of the rubber piston 160 in contact with the upper surface of the backup plate 150 in a curved shape having a radius value of about 1.0, the rubber piston 160 made of a flexible material is backed up. It can be prevented from being rolled into the gap (S) between the plate 150 and the guide part 130 . That is, when the lower surface of the rubber piston 160 is formed in a flat shape without a curved surface, the rim portion of the rubber piston 160 moves in the vertical direction in the gap between the backup plate 150 and the guide part 130 ( S) and may be damaged.

Therefore, when a curved surface is formed on the lower rim 161 of the rubber piston 160 that comes into contact with the upper surface of the backup plate 150, the rubber piston 160 generated as the outer diameter of the backup plate 150 is reduced. Damage can be prevented, which can improve the airtightness of the thermostat 100.

According to the present invention, the wax (W) may be formed of a mixture of high-temperature melting paraffin and low-temperature melting paraffin. For example, the wax W may include high-temperature molten paraffin having a first temperature at which the main valve 171 is opened as a melting point, and low-temperature molten paraffin having a second temperature lower than the first temperature as a melting point. That is, the first temperature may be referred to as an opening temperature at which the main valve 171 is opened. Here, the paraffin is a mixture of methane-based hydrocarbons having a composition of C _n H _2n+2 , and the melting points of the high-temperature melting paraffin and the low-temperature melting paraffin can be controlled by adjusting the amount of the hydrocarbon mixture contained therein.

For example, when the temperature of the cooling water is higher than the second temperature and lower than the first temperature, the cooling water introduced into the space between the rubber piston 160 and the backup plate 150 due to the expansion of the wax W is Discharged to the outside of the space, the main valve 171 may not yet open. Specifically, the second temperature, which is the melting point of the low-temperature melting paraffin, may be formed at a temperature 10° C. lower than the first temperature, which is the melting point of the high-temperature melting paraffin. For example, the second temperature may be set to 75°C to 95°C, which is the temperature at which the main valve 171 is opened, and the second temperature may be set to 65°C to 85°C, which is 10°C lower than this.

In this way, as the wax W is formed of a mixture of high-temperature molten paraffin and low-temperature molten paraffin having different melting points, the low-temperature molten paraffin helps to discharge the coolant adhered between the rubber piston 160 and the backup plate 150. can That is, by first expanding the low-temperature molten paraffin before the main valve 171 opens, the semi-fluid 121 and the rubber piston 160 move downward, so that the cooling water adhered between the rubber piston 160 and the cylinder It can be discharged through the gap (S) between the backup plate 150 and the guide part 130.

5 is a graph showing the lift of the wax according to the contents of high-temperature melting paraffin and low-temperature melting paraffin included in the wax of the present invention. Here, wax A contains 85% hot melt paraffin and 15% cold melt paraffin, wax B contains 80% hot melt paraffin and 20% cold melt paraffin, and wax C contains 75% hot melt paraffin and 25% cold melt paraffin. Wax D may include 70% of high-temperature melting paraffin and 30% of low-temperature melting paraffin.

Referring to FIG. 5 , the wax W may include 25 to 30% of low-temperature melting paraffin. This is because when the low-temperature melting paraffin is provided in less than 25% of the total amount of the wax (W), the expansion speed is slow due to the small amount of the low-temperature melting paraffin and the rubber piston 160 and the backup plate 150 before the main valve 171 opens. This is because it may not be possible to discharge the coalesced cooling water, and if it exceeds 30%, the main valve 171 may not be able to discharge the coalesced cooling water because the main valve 171 is opened first before discharging the coalesced cooling water.

That is, the main valve 171 can be opened by the compressive force of the main valve elastic member 173. In this embodiment, when the wax W contains 25 to 30% of low-temperature molten paraffin, the second temperature or higher In this state, the compressive force of the main valve elastic member 173 does not open the main valve 171, but coolant adhered between the rubber piston 160 and the backup plate 150 can be discharged.

Therefore, when the temperature of the cooling water is provided between the preset second temperature and the first temperature, the high-temperature molten paraffin does not expand and only the low-temperature molten paraffin expands, so that the semi-fluid 121 and the rubber piston do not open the main valve 171. 160 can be moved downward, whereby the coolant adhered between the rubber piston 160 and the cylinder can be discharged through the gap S between the backup plate 150 and the guide part 130.

An operation of controlling the outlet temperature of the engine ENG through the vehicle thermostat 100 will be described with reference to FIGS. 2 to 5 .

When the vehicle thermostat 100 is disposed on the outlet side of the engine ENG, the discharge pressure of the water pump W/P acts on the vehicle thermostat 100 to close the main valve 171 and the bypass valve 172. The temperature of the vehicle thermostat 100 increases because it receives a large load when changing and controls the temperature of the outlet side of the overheated engine ENG.

In this state, when the temperature of the cooling water circulating through the outlet side of the engine ENG exceeds a certain value, the volume of the wax W filled in the wax case 120 increases and expands. As the wax W expands, the diaphragm 121 is pressed downward, and the semi-fluid 122, the rubber piston 160, the backup plate 150, and the piston 140 are formed by the diaphragm 121. It can slide downward in the guide part 130 .

Then, the valve guide part 170 comes into contact with the piston 140 and moves in the same direction as the piston 140, and a space may be formed between the housing 110 and the main valve 171. Accordingly, the upper cooling water passage 110a, which was blocked by the main valve 171, is opened, and the cooling water discharged from the cooling water passage 10 may be supplied to the radiator RAD through the upper cooling water passage 110a. . The cooling water cooled by the radiator RAD is supplied to the engine ENG by the water pump W/P. At this time, since the outer diameter of the backup plate 150 is smaller than the inner diameter of the guide part 130, a gap (S) between the backup plate 150 and the guide part 130 allows the coalesced coolant to flow toward the piston 140. ) is formed, it is possible to prevent the coolant from adhering between the backup plate 150 and the rubber piston 160 .

Meanwhile, when the valve guide part 170 moves downward, the bypass valve 172 also moves downward. Accordingly, the bypass valve 172 may block the bypass passage 20 by blocking the lower cooling water passage 110b disposed thereunder. That is, when the cooling water passage 10 is opened by the main valve 171, the bypass passage 20 is blocked by the bypass valve 172. Then, the supply of cooling water to the bypass passage 20 is stopped, and the cooling water is supplied only to the cooling water passage 10 so that it can be cooled through the radiator RAD.

In other words, if the temperature of the coolant circulating at the outlet side of the engine ENG is higher than a certain value, the coolant is engine (ENG) → thermostat 100 → radiator (RAD) → water pump (W/P) → engine ( ENG) and lowers the high-temperature coolant temperature to low-temperature.

If the temperature of the cooling water by the radiator RAD is below a certain value, the wax W shrinks, and the main valve 171 rises due to the restoring force of the main valve elastic member 173. Then, since the cooling water passage 10 is blocked by the main valve 171 and the bypass passage 20 is opened by the bypass valve 172, the cooling water can circulate through the bypass passage 20 again. . That is, when the temperature of the coolant circulating at the outlet side of the engine ENG is less than a certain value, the coolant flows from the engine ENG→thermostat 100→bypass flow path 20→water pump W/P→engine It moves in order of (ENG), and overcooling of engine (ENG) can be prevented.

The present invention has been described with reference to an embodiment shown in the accompanying drawings, but this is only exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. You will be able to. Therefore, the true protection scope of the present invention should be defined only by the appended claims.

110: housing
120: wax case
130: guide unit
140: piston
150: backup plate
160: rubber piston
170: valve guide unit
171: main valve
172: bypass valve
173: main valve elastic member
174: bypass valve elastic member

Claims (8)

In a vehicle thermostat filled with wax that expands or contracts according to the temperature of the coolant,
a piston reciprocating by expansion or contraction of the wax;
a backup plate disposed between the wax and the piston and having one surface in contact with the piston;
a rubber piston disposed between the wax and the piston and having one surface in contact with the backup plate; and
a guide unit configured to surround the piston, the back-up plate, and the rubber piston and guide the vertical movement according to the expansion or contraction of the wax;
including,
A gap through which the cooling water flows is formed between the backup plate and the guide part;
The backup plate contracts or expands according to the temperature of the cooling water, and the cooling water can flow between the backup plate and the guide part even when the temperature of the cooling water reaches a maximum value and the backup plate expands to the maximum. A car thermostat in which a gap is formed. According to claim 1,
An outer diameter of the backup plate is smaller than an inner diameter of the guide part. delete In a vehicle thermostat filled with wax that expands or contracts according to the temperature of the coolant,
a piston reciprocating by expansion or contraction of the wax;
a backup plate disposed between the wax and the piston and having one surface in contact with the piston;
a rubber piston disposed between the wax and the piston and having one surface in contact with the backup plate; and
a guide unit configured to surround the piston, the back-up plate, and the rubber piston and guide the vertical movement of the wax according to expansion or contraction;
including,
A gap through which the cooling water flows is formed between the backup plate and the guide part;
One surface of the rubber piston is in contact with the backup plate, and an edge of the surface of the rubber piston that is in contact with the backup plate is formed as a curved surface. In a vehicle thermostat filled with wax that expands or contracts according to the temperature of the coolant,
a piston reciprocating by expansion or contraction of the wax;
a backup plate disposed between the wax and the piston and having one surface in contact with the piston;
a rubber piston disposed between the wax and the piston and having one surface in contact with the backup plate; and
a guide unit configured to surround the piston, the back-up plate, and the rubber piston and guide the vertical movement according to the expansion or contraction of the wax;
including,
A gap through which the cooling water flows is formed between the backup plate and the guide part;
A valve guide portion formed in a form surrounding the guide portion and the piston and elastically supported in the housing and having a main valve and a bypass valve for opening and closing the coolant flow path and the bypass flow path,
The wax is formed by mixing high-temperature molten paraffin having a melting point at a first temperature at which the main valve opens and low-temperature molten paraffin having a second temperature lower than the first temperature as a melting point. According to claim 5,
When the temperature of the cooling water is greater than the second temperature and less than the first temperature, the cooling water introduced into the space between the rubber piston and the backup plate due to the expansion of the wax is discharged to the outside of the space, The thermostat for a vehicle in which the main valve is not yet opened. a housing selectively communicating with the coolant passage and the bypass passage of the vehicle;
a wax case disposed in the housing and filled with wax that expands or contracts according to the temperature of the cooling water;
a guide unit coupled to a lower portion of the wax case;
a piston disposed within the guide unit and reciprocating by expansion or contraction of the wax;
a backup plate inserted into the guide unit, disposed between the wax and the piston, and having one surface in contact with the piston;
a rubber piston inserted into the guide unit, disposed between the wax and the piston, and having one surface in contact with the backup plate; and
a valve guide portion configured to surround the guide portion and the piston, elastically supported within the housing, and including a main valve and a bypass valve for opening and closing the coolant passage and the bypass passage;
including,
The backup plate is coupled to the inside of the guide portion, but is coupled in a state in which the inside of the guide portion is not sealed,
The backup plate contracts or expands according to the temperature of the cooling water, and even when the temperature of the cooling water reaches a maximum value and the backup plate expands to the maximum, the cooling water can flow between the backup plate and the guide part A car thermostat in which a gap is formed. a housing selectively communicating with the coolant passage and the bypass passage of the vehicle;
a wax case disposed in the housing and filled with wax that expands or contracts according to the temperature of the cooling water;
a guide unit coupled to a lower portion of the wax case;
a piston disposed within the guide unit and reciprocating by expansion or contraction of the wax;
a backup plate inserted into the guide unit, disposed between the wax and the piston, and having one surface in contact with the piston;
a rubber piston inserted into the guide unit, disposed between the wax and the piston, and having one surface in contact with the backup plate; and
a valve guide portion configured to surround the guide portion and the piston, elastically supported within the housing, and including a main valve and a bypass valve for opening and closing the coolant passage and the bypass passage;
including,
The backup plate is coupled to the inside of the guide portion, but is coupled in a state in which the inside of the guide portion is not sealed,
One surface of the rubber piston is in contact with the backup plate, and an edge of the surface of the rubber piston that is in contact with the backup plate is formed as a curved surface.

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