Abstract:
A thermostat apparatus may include a valve body including a first valve formed to open or close a first passage thereon, and a second valve integrally connected to the first valve and opening or closing a second passage, an elastic member that elastically biases the valve body toward the first passage such that the first valve closes the first passage and the second valve opens the second passage, and a drive member that selectively pushes the valve body toward the second passage such that the first valve opens the first passage and the second valve closes the second passage.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    The present application claims priority to Korean Patent Application No. 10-2012-0036338 filed on Apr. 6, 2012, the entire contents of which is incorporated herein for all purposes by this reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a thermostat that changes a passage of a coolant depending on the temperature of the coolant and actively controls the coolant temperature to prevent overheating thereof. 
         [0004]    2. Description of Related Art 
         [0005]    A thermostat for a vehicle is disposed between an engine and a radiator, is automatically opened/closed by the temperature variation of coolant to adjust the flow rate of the coolant, and therefore the temperature of the coolant is controlled in a predetermined range. 
         [0006]    A mechanical thermostat expands wax depending on the temperature of the coolant, and the expanding force of the wax makes a piston move the valve of the thermostat. 
         [0007]    The mechanical thermostat is operated in a predetermined opening/closing temperature of the coolant to open/close the valve only in a predetermined temperature condition, and therefore the mechanical thermostat does not actively move against changes of the driving circumstances of the vehicle. 
         [0008]    Accordingly, an electrical thermostat has been introduced to complements the drawback of the mechanical thermostat, and the electrical thermostat is operated to sustain the coolant temperature in an optimized range. 
         [0009]    The electrical thermostat actively controls the coolant temperature of the engine according to the driving circumstances such as the load level of the vehicle to sustain the optimized coolant temperature, and the electrical thermostat can improve fuel consumption efficiency and reduce exhaust gas. 
         [0010]    Meanwhile, three coolant passages are formed in the electrical thermostat and the mechanical thermostat as an example. A first passage is connected to a radiator, a second passage is connected to a coolant outlet of the engine, and a third passage is connected to a coolant inlet of the engine. Here, the coolant pump can be disposed between the third passage and the coolant inlet. 
         [0011]    In this case, the first valve of the thermostat opens/closes the first passage, the second valve opens/closes the second passage, and the third passage is opened. Further, a guide can be disposed to guide the movement of the first and second valve. 
         [0012]    As described above, when the first valve, the second valve, and the guide are separately disposed, the number of components is increased and the structure can be complicated. 
         [0013]    The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art. 
       BRIEF SUMMARY 
       [0014]    Various aspects of the present invention are directed to providing a thermostat having advantages of making the structure of a first valve, a second valve, and a guide, which open/close a passage of a coolant become simple, and reducing the number of components. 
         [0015]    Further, the present invention provides a thermostat that actively controls the coolant temperature of the engine and improves the performance of the engine. 
         [0016]    In an aspect of the present invention, a thermostat apparatus may include a valve body having a first valve formed to open or close a first passage thereon, and a second valve integrally connected to the first valve and opening or closing a second passage, an elastic member that elastically biases the valve body toward the first passage such that the first valve closes the first passage and the second valve opens the second passage, and a drive member that selectively pushes the valve body toward the second passage such that the first valve opens the first passage and the second valve closes the second passage. 
         [0017]    An O-ring groove is formed in an outer circumference of the first valve at a part corresponding to an inner circumference surface of the first passage and a valve O-ring is disposed in the O-ring groove. 
         [0018]    A mounting space is formed along a central portion of the valve body, wherein the drive member is inserted into the mounting space, and wherein the drive member may include a piston that selectively pushes a piston support portion that is integrally formed with the second valve. 
         [0019]    The drive member selectively pushes the valve body to make the second valve close the second passage while an end portion of the valve body is inserted into the second passage. 
         [0020]    The valve body may include frame elements that are disposed with a distance in a circumferential direction based on the mounting space and connects the first valve and the second valve. 
         [0021]    A first reinforcement portion is integrally formed with the frame elements between the first valve and the second valve in a circumferential direction of the valve body, wherein a second reinforcement portion is integrally formed with the valve body at a part that is slidably inserted into the second passage in a circumferential direction of the valve body. 
         [0022]    The second reinforcement portion is formed at a lower side of the second valve. 
         [0023]    A diameter of the second passage is larger than a diameter of the second reinforcement portion and smaller than a diameter of the second valve. 
         [0024]    The second reinforcement portion may have a circular ring shape corresponding to an interior circumference of the second passage. 
         [0025]    The first passage is connected to a radiator, wherein the second passage is connected to a coolant outlet of an engine, and wherein the third passage is connected to a coolant inlet of the engine. 
         [0026]    The thermostat according to an exemplary embodiment of the present invention has a structure in which the first valve, the second valve, and the guide are integrally formed such that the overall structure becomes simple and the number of components is reduced. 
         [0027]    Further, the thermostat according to an exemplary embodiment of the present invention actively controls the temperature of the coolant circulating in the engine to improve the fuel consumption efficiency and the performance of the engine. 
         [0028]    The methods and apparatuses of the present invention have other features and advantages which will be apparent from or are set forth in more detail in the accompanying drawings, which are incorporated herein, and the following Detailed Description, which together serve to explain certain principles of the present invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0029]      FIG. 1  is a partial cross-sectional view of a thermostat that is provided on an engine according to an exemplary embodiment of the present invention. 
           [0030]      FIG. 2  is a side view showing that a glow plug is mounted on a valve body in a thermostat according to an exemplary embodiment of the present invention. 
           [0031]      FIG. 3  is a perspective view showing a valve body in a thermostat according to another exemplary embodiment of the present invention. 
           [0032]      FIG. 4  is a partial cross-sectional view showing that a thermostat is operated in an engine according to an exemplary embodiment of the present invention. 
       
    
    
       [0033]    It should be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of various features illustrative of the basic principles of the invention. The specific design features of the present invention as disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes will be determined in part by the particular intended application and use environment. 
         [0034]    In the figures, reference numbers refer to the same or equivalent parts of the present invention throughout the several figures of the drawing. 
       DETAILED DESCRIPTION 
       [0035]    Reference will now be made in detail to various embodiments of the present invention(s), examples of which are illustrated in the accompanying drawings and described below. While the invention(s) will be described in conjunction with exemplary embodiments, it will be understood that the present description is not intended to limit the invention(s) to those exemplary embodiments. On the contrary, the invention(s) is/are intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims. 
         [0036]    An exemplary embodiment of the present invention will hereinafter be described in detail with reference to the accompanying drawings. 
         [0037]      FIG. 1  is a partial cross-sectional view of a thermostat that is provided on an engine according to an exemplary embodiment of the present invention. 
         [0038]    Referring to  FIG. 1 , an engine includes a radiator  150 , a coolant outlet  160  of an engine, a coolant inlet  170  of an engine, and a thermostat  100 . 
         [0039]    The thermostat  100  includes a thermostat case  137 , and a first passage  155  is formed to be connected to the radiator  150 , a second passage  165  is formed to be connected to the coolant outlet  160 , and a third passage  175  is connected to the coolant inlet  170  in the thermostat case  137 . 
         [0040]    A coolant pump in an exemplary embodiment of the present invention is disposed between the third passage  175  and the coolant inlet  170  to circulate coolant from the thermostat  100  to the engine. 
         [0041]    As shown in drawings, the first passage  155  is formed at an upper side, the second passage  165  is formed at a lower side, and the third passage  175  is formed between the first and second passages  155  and  165 . 
         [0042]    A joining space  139  is formed in the thermostat case  137  to be connected to the first passage  155 , the second passage  165 , and the third passage  175 , and a valve body  125  is disposed in the joining space  139 . 
         [0043]    A first valve  200  is integrally formed at an upper end portion of the valve body  125  to selectively close the first passage  155 , and a second valve  205  is integrally formed at a lower end portion of the valve body  125  to selectively close the second passage  165 . Further, a valve O-ring  130  is mounted along an exterior circumference of the first valve  200  to contact the interior circumference of the first passage  155 . 
         [0044]    A main spring  145  is disposed inside the thermostat case  137 , and an upper end portion of the main spring  145  elastically supports the lower end portion of the first valve  200  in an upper direction, and a lower end portion of the main spring  145  is supported by an inner side of the thermostat case  137 . 
         [0045]    The main spring  145  has a coil spring structure, and the valve body is inserted into the coil of the main spring  145  except the first valve  200  and the part that that is inserted into the second passage  165 . 
         [0046]    Further, a mounting space is formed along a central portion of the valve body  125  from an upper end side to a lower end side, and a drive member that moves the valve body  125  is inserted into the mounting space  215 . 
         [0047]    The drive member includes a piston support portion  225 , a piston  120 , a rubber piston  148 , a piston guide  127 , a semi-fluid  147 , a diaphragm  115 , wax  110 , a wax case  135 , and a glow plug  105 , wherein the glow plug  105  is electrically connected to a connector  140 . 
         [0048]    The piston support portion  225  is formed at a central portion of the second valve  205  that is formed at a lower end portion of the valve body  125 . 
         [0049]      FIG. 2  is a side view showing that a glow plug is mounted on a valve body in a thermostat according to an exemplary embodiment of the present invention, and  FIG. 3  is a perspective view showing a valve body in a thermostat according to another exemplary embodiment of the present invention. 
         [0050]    Referring to  FIG. 2  and  FIG. 3 , an O-ring groove  300  is formed at an exterior circumference of the first valve  200  and the valve O-ring  130  is disposed in the groove  300 . 
         [0051]    Further, a mounting space  215  is formed at a central portion of the valve body  125  along the length direction of the valve body  125 , and the piston guide  127 , the wax case  135 , and the glow plug  105  of the drive member are inserted into the mounting space  215 . 
         [0052]    The valve body  125  includes frame elements  210  that are formed with a distance along the circumference direction such that the drive member that is inserted into the mounting space  215  of the valve body  125  can be shown from the outside of the valve body, and the first valve  200  and the second valve  205  are integrally formed with the frame elements  210 . 
         [0053]    Referring to  FIG. 2 , the valve body  125  includes three frame elements  210 . The number of frame elements  210  can be varied to two or six according to the design specification. 
         [0054]    The piston support portion  225  is formed at a central portion of the second valve  205  to correspond to the piston  120 , and the piston support portion  225  is integrally formed with the second valve  205 . 
         [0055]    A second reinforcement portion  220  is formed at a lower side of the second valve  205  and is formed to integrally connect a lower end portion of the frame element  210  in a circumference direction of the valve body  125 , and a first reinforcement portion  217  is formed between the second valve  205  and the first valve  200  to integrally connect the frame element  210  in a circumference direction of the valve body  125 . 
         [0056]    As shown in drawings, the first reinforcement portion  217 , the second valve  205 , and the second reinforcement portion  220  have a circular ring shape that integrally connects the frame elements  210  in a circumference direction. 
         [0057]    Further, the second reinforcement portion has a circular ring shape corresponding to the second passage, and the exterior circumference of the second reinforcement portion can slide with the interior circumference of the second passage. 
         [0058]    The relative position of the first reinforcement portion  217 , the second valve  205 , and the second reinforcement portion  220  can be predetermined by the design specification. Further, as shown in  FIG. 3 , the second reinforcement portion  220  can be eliminated. 
         [0059]    Referring to  FIG. 1 , a lower end portion of the frame element  210  of the valve body  125  is inserted into the second passage  165 . Accordingly, the valve body  125  is guided by the second passage  165 . 
         [0060]    Referring to  FIG. 3 , three first frame elements  210   a  are formed at an upper side of the second valve  205  and six second frame elements  210   b  are formed at a lower side of the second valve  205 . 
         [0061]    The six second frame elements  210   b  that are formed at a lower side of the second valve  205  are parts that can be inserted into the second passage  165 . As described above, the number of second frame elements is larger than that of the first frame elements  210   a . Accordingly, the valve body  125  is securely guided by the second passage  165 . 
         [0062]      FIG. 4  is a partial cross-sectional view showing that a thermostat is operated in an engine according to an exemplary embodiment of the present invention. 
         [0063]    Referring to  FIG. 4 , the coolant that is supplied through the coolant outlet  160  joins the joining space  139  and then is supplied to the coolant inlet  170 . Further, when the temperature of the coolant is increased or the current is supplied to the glow pug, the temperature of the wax  110  is increased. 
         [0064]    While the temperature of the wax is increased, the wax  110  is expanded to expand the diaphragm  115  in a lower direction. 
         [0065]    If the diaphragm  115  is expanded in a lower direction, the rubber piston  148  and the piston  120  is moved downward thereby and the piston  120  pushes the piston support portion  225  of the valve body  125  in a lower direction. 
         [0066]    If the piston support portion  225  and the valve body  125  are moved downward, the first valve  200  opens the first passage  155  and the second valve  205  closes the second passage  165  or reduces the opening rate of the second passage  165 . 
         [0067]    Accordingly, the flow rate that is supplied through the second passage  165  is increased and the flow rate that is supplied through the first passage  155  is increased. Because the first passage  155  is connected to the radiator  150 , the amount of the coolant that is cooled by the radiator  150  is increased. Accordingly, the temperature of the entire coolant is not raised or is lowered to be effectively sustained in a predetermined range. 
         [0068]    For convenience in explanation and accurate definition in the appended claims, the terms “upper”, “lower”, “inner” and “outer” are used to describe features of the exemplary embodiments with reference to the positions of such features as displayed in the figures. 
         [0069]    The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and their practical application, to thereby enable others skilled in the art to make and utilize various exemplary embodiments of the present invention, as well as various alternatives and modifications thereof. It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents.