JP2013124618A - Thermostat device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermostat device which eliminates the problems on an increase in passing water pressure loss of cooling water, a reduction in durability due to corrosion damages by the cooling water, and low moldability when a housing is molded, while improving performance as well as durability.SOLUTION: The thermostat device includes a piston rod 17, which slides in response to changes in the volume of a thermal expansion body that thermally expands or contracts by temperature changes of cooling water in a valve housing 20 provided with a cooling water passage 21 constituting a cooling water channel of an internal combustion engine. A shaft support part 23 for pivotally supporting an outer end of the piston rod is formed to be recessed from an inner wall surface that forms the cooling water passage in the valve housing.

Description

  The present invention relates to a cooling water circuit for an engine that circulates cooling water for cooling an internal combustion engine (hereinafter referred to as an engine) used for an automobile or the like with a heat exchanger (hereinafter referred to as a radiator). TECHNICAL FIELD The present invention relates to a thermostat device that is a temperature-sensing automatic valve that is used to control the coolant temperature by switching the flow of engine coolant by operating according to the temperature change of the engine, and in particular, a thermoelement in a valve housing with a coolant inlet. The present invention relates to a housing-integrated thermostat device incorporating a main body such as a valve body.

  In order to cool an automobile engine, a water-cooled cooling system using a radiator is generally used. Conventionally, in this type of cooling system, a thermostat using a thermal expansion body that adjusts the amount of cooling water to be circulated to the radiator side is used so that the temperature of the cooling water introduced into the engine can be controlled.

  That is, a control valve such as a thermostat using the above-described thermal expansion body is installed in a part of the cooling water passage, for example, the inlet side or the outlet side of the engine, and the control valve is closed when the cooling water temperature is low. If the coolant temperature circulates through the bypass passage without going through the radiator, and the coolant temperature rises, the control valve is opened and the coolant is circulated through the radiator, so that the engine coolant temperature is required. It can be controlled to the state of.

  Conventionally, this type of thermostat device includes a thermo element enclosing a thermal expansion body that operates according to a temperature change of a fluid, and a main body frame that holds the thermo element. Both end sides of the thermo element are substantially umbrella-shaped. First and second valve bodies are provided. The thermo element includes a rod that moves forward and backward by a thermal expansion body that expands and contracts by sensing the temperature of the fluid, and the valve body opens and closes the fluid passage in conjunction with the movement of the rod. (For example, refer to Patent Document 1).

  However, this type of thermostat device has a structure in which a valve seat on which a first valve element is seated is provided in a part of a main body frame, and the entire device is incorporated and disposed in a fluid passage. Therefore, the number of components is large and the structure is complicated.There are many parts that resist the flow of fluid, the resistance to water flow increases, the pressure loss increases, and there is a problem in controlling the required flow rate. Met.

  For this reason, a housing-integrated thermostat device has been proposed in which a housing that forms a fluid passage is used and a main body portion including a thermo element, a valve body, and the like is incorporated therein to reduce the number of parts. (For example, refer to Patent Document 2).

  In such a thermostat device integrated with a housing, it is confirmed that the pressure loss can be reduced to some extent because the number of components facing the fluid passage is reduced, and the number of parts that obstruct the fluid flow is also reduced.

Japanese Patent No. 3225386 JP-A-2005-330920

  However, in this type of housing-integrated thermostat device, in the conventional structure, a boss portion that protrudes from the inner wall surface of the housing with a shaft support portion that pivotally supports the outer end of the piston rod accompanying a temperature change in the thermoelement. The boss portion may affect the flow of fluid in the cooling water passage from which the boss portion protrudes, leading to an increase in water pressure loss as a thermostat. Furthermore, as described above, since the boss portion protruding into the cooling water passage is always exposed to the cooling water, it is easily damaged by erosion, resulting in problems such as a problem in durability.

  More specifically, this boss has a function of preventing and positioning the piston rod of the thermo element, and if the insertion allowance is small, the piston rod will come off and the thermostat will break down. Connected. In addition, in this type of thermostat device, when water is poured into a finished vehicle, the thermostat is forcibly opened. However, there is a possibility that the above-mentioned problem of the piston rod coming out may occur. .

  Further, the presence of the above-described boss portion causes a serious problem when the valve housing is manufactured by injection molding or the like in the thermostat device. That is, in order to ensure a sufficient amount of insertion of the above-described piston rod, it is necessary to form the boss portion in a long cylindrical shape. Furthermore, in order to obtain a smooth flow of cooling water, the volume of the boss portion must be reduced to have a thin cylindrical shape or the like. However, when trying to form a thin cylindrical boss in this way, there arises a problem that damage due to the erosion of the cooling water is likely to occur.

  In addition, this type of valve housing is generally integrally formed of a heat-resistant synthetic resin material or the like. In order to form the boss portion described above into a thin cylindrical shape at the time of molding, the hot water in the boss portion is formed. The flow (filling degree of the resin material) is deteriorated, it becomes easy to generate welds, and there is a problem in terms of heat dissipation near the boss portion.

  Further, in the injection molding process of the valve housing, when the next product is molded after molding the previous product, the boss portion of the slide mold that forms the inside of the dome-shaped portion of the housing is not sufficiently cooled. Has occurred. If the slide mold is filled with heat and is not cooled sufficiently, the product will not be cooled well during molding, and it will be easy to induce `` thermal sink marks '' after opening the slide mold, which is a problem in ensuring product quality. It is.

  Furthermore, when glass fibers are mixed in the valve housing in order to increase the strength, the orientation of the glass fibers tends to be complicated, and as a result, there is a problem that the strength is weakened because the orientation is not appropriate.

  Further, in the valve housing, there is a problem that it is difficult to perform “burr” processing that occurs on the mating surfaces of the slide molds on the hose mouth side and the dome-shaped portion side.

  The present invention has been made in view of such circumstances, problems such as increased pressure loss due to cooling water flow resistance, durability problems due to erosion damage due to cooling water, and aspects such as formability during manufacturing. The purpose is to obtain a thermostat device that solves the problem of product quality from, and is superior in terms of performance and durability.

  In order to meet such an object, a thermostat device according to the present invention (the invention described in claim 1) is incorporated in a valve housing provided with a cooling water passage constituting a cooling water passage of an internal combustion engine, and changes in temperature of the cooling water. A thermal expansion body that thermally expands or contracts due to the thermal expansion body, and has a piston rod that slides due to thermal expansion and contraction of the thermal expansion body. In a thermostat device for opening and closing a valve body with respect to a valve seat formed in a valve housing, a shaft support portion that pivotally supports the outer end of the piston rod is provided outside the cooling water passage.

  The thermostat device according to the present invention (the invention according to claim 2) is the thermostat device according to claim 1, wherein the shaft support portion that pivotally supports the outer end of the piston rod is formed from an inner wall surface that forms a cooling water passage in the valve housing. It is characterized by being formed in a recessed manner.

  The thermostat device according to the present invention (the invention described in claim 3) is the thermostat device according to claim 2, wherein a bulging portion protruding from the outer wall surface of the valve housing is provided, and the shaft support portion is provided in the bulging portion of the valve housing. It is characterized by being formed to be recessed from the inner wall surface.

  As described above, according to the thermostat device of the present invention, while securing a sufficient amount of insertion of the piston rod, by forming the boss portion that pivotally supports it from the inner wall surface of the valve housing, Since it is provided outside the cooling water passage, it solves the various problems that have been the conventional problems despite the simple structure, and has the following various excellent effects.

  That is, according to the present invention, unlike the conventional boss portion structure, the shaft support is formed outside the cooling water passage, so that erosion by the cooling water acts only on the inside of the shaft support, and the erosion progresses. Can be suppressed, and durability can be improved.

  Further, according to the present invention, since the conventional thin cylindrical boss portion is unnecessary, the structure of the valve housing itself is simplified, the moldability at the time of molding is improved, and the heat dissipation at the time of molding is also improved. In some cases, it is possible to embed a cooling device in the mold for the outer shape of the valve housing, making it easier to control the temperature of the mold, stabilizing the mold cooling, and suppressing "thermal sinking". Is stable and the product quality is also good.

  Furthermore, since there is no extra protrusion on the inside of the valve housing, the “burr” treatment of the mating surfaces of the slide molds on the hose side and the dome-shaped portion side is facilitated.

  Further, according to the present invention, the shaft support portion is provided in the bulging portion that protrudes to the outside of the valve housing, and the injection port is provided at the top portion thereof, thereby improving the hot water flow at the time of injection molding. Generation can be suppressed and the strength of the product can be increased.

  Furthermore, according to this invention, the moldability of a valve housing can be improved by providing the injection port at the time of valve housing manufacture in the top part of the bulging part mentioned above.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic cross-sectional view illustrating a schematic configuration of an entire thermostat device according to an embodiment of the thermostat device according to the present invention. FIG. 2 is a schematic cross-sectional view showing the thermostat device of FIG. 1 in a cross-section from another direction. It is a schematic sectional drawing which shows another Example of the thermostat apparatus which concerns on this invention.

  A boss that protrudes into the cooling water passage conventionally by forming a shaft support portion that pivotally supports the outer end of the piston rod from the inner wall surface of the valve housing to be recessed from the cooling water passage, for example, from the inner wall surface of the valve housing. Suppresses erosion damage to the part, improves durability, simplifies the mold structure for molding, and improves moldability and molding quality.

1 and 2 show an embodiment of a thermostat device according to the present invention.
In these figures, a thermostat device, which is a temperature-sensing automatic valve indicated by reference numeral 10, is attached to the intersection of a cooling water channel on the radiator side and a bypass channel from the engine outlet side in, for example, an automotive engine cooling system. It is used to control the temperature of the cooling water reaching the engine inlet by selectively switching the flow of the cooling water in the first and second fluid flow paths constituted by these passages.

  As shown in FIGS. 1 and 2, the thermostat device 10 includes a thermo element 11 that is an operating body that operates according to a temperature change of a fluid, and a substantially flat umbrella is provided on one end side (upper side in the figure) of the thermo element 11. A first valve body 12 having a shape is provided, and a second valve body 13 is provided on the other end side (lower side in the figure). In addition, a coil spring 14 that is an urging means for urging the first valve body 12 to the valve closing position and a main body frame 15 that also serves as a spring retainer are fitted and inserted into the central portion of the thermo element 11 in the axial direction. Is provided. The main body frame 15 is latched by a support leg on the valve housing side which is a fixing portion described later, thereby constantly urging the first valve body 12 through the coil spring 14 in the valve closing direction. It is a member that holds the thermo element 11 slidably.

  The thermo element 11 includes a temperature sensing unit 16 that encloses a thermal expansion body such as wax that senses the temperature of the fluid and expands and contracts, and the piston rod 17 can advance and retreat from the tip (upper end) of the temperature sensing unit 16. Protruding.

In the figure, reference numeral 20 denotes a valve housing provided with a cooling water passage inlet portion 20a as a fluid inlet on the hose opening side. Inside the valve housing 20, a cooling water passage 21 as a fluid passage is formed. A valve seat 22 is formed on the inner side of a dome-shaped portion with a flange provided in a part thereof so that the first valve body 12 can be seated thereon. The thermo element 11, the main body frame 15, and the like are incorporated in a state in which the valve body 12 can be seated on the valve seat 22.
In the figure, reference numeral 23 denotes a shaft support portion that latches and holds the outer end (upper end portion in the figure) of the piston rod 17. In the state of FIG. 2, the piston rod 17 is moved upward in FIG. 2 by the thermal expansion of the thermal expansion body. When protruding, the thermo element 11 and the first and second valve bodies 12 and 13 are moved downward in FIG. 2 so that the valve is closed and opened in FIGS. 1 and 2.

  As shown in FIGS. 1 and 2, the main body frame 15 is engaged with the distal ends of support legs 24 and 25 formed by extending two pieces extending in the radial direction in the valve housing 20 in the axial direction. It is held. As shown in FIG. 2, a groove portion (not shown) serving as a cooling water passage portion along the flow direction of the cooling water is formed in a part of the inner peripheral portion of these support legs. This groove portion prevents the flow of cooling water from being damaged by the presence of the support legs 24 and 25 when the valve is opened, particularly when the minute valve is opened, and the gap between the valve seat 22 and the valve body 12 is small. It is for minimization. When the groove portion is formed along the axial direction in this manner, the cooling water flows smoothly through the groove portion, and a flow having a high flow velocity flows around the thermoelement 11, so that an advantage of improving the temperature sensitivity is also obtained. . Of course, the inside of the support legs 24 and 25 may be formed in a hollow shape, and the cooling water passage portion may be formed along the flow direction of the cooling water, instead of the groove portion formed by the lightening.

  Further, as shown in FIG. 2, a hole 27 for circulating cooling water is formed in a part of the main body frame 15. This hole portion 27 can smoothly escape the flow having a high flow velocity flowing through the groove portion serving as the cooling water passage portion without being blocked by the main body frame 15. And if it does in this way, also in the main body frame 15 part, the suitable flow of a cooling water will be obtained and the temperature sensitivity of the thermoelement 11 will improve.

According to the present invention, in the thermostat device 10 having the above-described configuration, the shaft support portion 23 that supports and supports the outer end of the piston rod 17 is provided outside the cooling water passage 21, that is, inside the valve housing 20. It is characterized in that it is constituted by a bearing hole 31 formed by being recessed from the inner wall surface forming the cooling water passage 21.
Here, reference numeral 30 in the figure denotes a cylindrical bulging portion formed by bulging on the outer wall surface of the valve housing 20, and unlike the boss portion protruding into the cooling water passage as in the prior art, the cooling water erosion damage is The structure is difficult to receive.

  According to such a structure, the shaft support portion 23 that pivotally supports the piston rod 17 is formed so as to be recessed from the inner wall surface of the valve housing 20 while securing a sufficient insertion amount of the piston rod 17 that is necessary and sufficient for operation. Since it is provided outside the cooling water passage 21, it is possible to solve various problems which have been a problem in the related art despite the simple structure.

  That is, according to the above-described shaft support portion 23, unlike the conventional boss portion structure, the shaft support portion 23 is formed outside the cooling water passage 21, so that erosion due to cooling water acts only on the inside of the shaft support portion 23 (the bearing hole 31 portion). As a result, the progress of erosion can be suppressed as compared with the conventional structure, and the durability can be improved.

  In addition, according to the above-described structure, the conventional thin cylindrical boss portion is unnecessary, so the structure of the valve housing 20 itself, particularly the inner structure such as the cooling water passage 21, is simplified, and the moldability during molding is good. In addition, heat dissipation during molding is improved, temperature control of the mold is easy, cooling of the mold is stable, "heat sink" can be suppressed, dimensional accuracy is stable, and product quality is improved. But it will be good.

  Further, since there is no extra protrusion on the inner side of the valve housing 20, there is also an advantage that the “burr” processing of the mating surfaces of the slide molds on the hose side and the dome-shaped portion side is facilitated.

  In this embodiment, an injection port (not shown) at the time of manufacturing the valve housing 20 is provided at the top of the bulging portion 30. With such a structure, the effect of the structure of the bulging portion 30 protruding to the outside of the valve housing 20 is added, so that the hot water flow at the time of injection molding can be improved and the occurrence of “weld” can be suppressed. , Can increase the strength of the product, ensure product quality, and improve durability.

FIG. 3 shows another embodiment of the present invention. In this embodiment, in addition to the above-described embodiment, the inner wall surface of the passage, the pipe port so that the flow of the cooling water along the inner wall surface of the passage constituting the cooling water passage 21 in the valve housing 20 flows more smoothly. This is a case where the joint portion between the dome portion and the boundary portion between the boss portion and the dome portion has a gentle shape with no corners or the like.
If comprised in this way, compared with the example of FIG. 1, the flow from a dome-shaped part side to a pipe mouth side will flow even more smoothly because there are no joints, stepped parts, corners, and the like.

  Note that the present invention is not limited to the structure described in the above-described embodiment, and it goes without saying that the shape, structure, and the like of each part constituting the thermostat device 10 can be appropriately modified and changed. For example, in the above-described embodiment, a case has been described in which the first valve body 12 is provided in the central portion of the thermoelement 11 in the axial direction and the second valve body 13 is provided on the lower end side. The invention is not limited to this, and the second valve body 13 may be provided as needed.

  In the above-described embodiment, the example in which the thermostat device 10 is incorporated in the engine cooling water circuit on the inlet side of the engine has been described. However, the present invention is not limited to this and is incorporated in the outlet portion of the engine. Needless to say, the same effects can be obtained in this case.

  DESCRIPTION OF SYMBOLS 10 ... Thermostat apparatus, 11 ... Thermo element, 11b ... Piston rod, 12 ... 1st valve body, 13 ... 2nd valve body, 14 ... Coil spring, 15 ... Main body frame, 16 ... Temperature sensing part, 17 ... Piston Rod, 20 ... valve housing, 21 ... cooling water passage, 22 ... valve seat, 23 ... shaft support, 24, 25 ... support leg, 30 ... bulge, 31 ... bearing hole.

Claims (3)

A thermal expansion body that is incorporated in a valve housing provided with a cooling water passage that constitutes a cooling water passage of the internal combustion engine and that thermally expands or contracts due to a change in the temperature of the cooling water is incorporated. In a thermostat device having a moving piston rod and opening and closing a valve body with respect to a valve seat formed in the valve housing by sliding of the piston rod accompanying a volume change of the thermal expansion body,
A thermostat device characterized in that a shaft support portion that supports the outer end of the piston rod is provided outside the cooling water passage. The thermostat device according to claim 1,
A thermostat device characterized in that a shaft support portion that pivotally supports the outer end of the piston rod is recessed from an inner wall surface that forms a cooling water passage in the valve housing. The thermostat device according to claim 2,
Providing a bulging portion protruding from the outer wall surface of the valve housing;
The thermostat device, wherein the shaft support portion is formed in the bulging portion by being recessed from the inner wall surface of the valve housing.

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