Abstract:
A thermal expansion valve  100  has a valve chamber in a valve body  110 , and controls the flow rate of refrigerant from a condenser and a receiver, and the refrigerant travels to an evaporator through a passage  132 . Refrigerant returning from the evaporator transmits the temperature of refrigerant to a heat sensing shaft connecting to a power element portion  36  while traveling through a passage  34 . A cover  200  has a head portion  220  and a tapered portion  210 , and is mounted to the top portion of the valve body  110 . Tapered outer surfaces  212  of the tapered portion of the cover  200  and tapered surfaces  114  of the valve body  110  form approximately identical surfaces. A concave portion  221  of the head portion  220  covers the power element portion  36 , and its peak portion forms a curved surface  222.

Description:
FIELD OF THE INVENTION 
     This invention relates to a thermal expansion valve used in a refrigeration cycle. 
     DESCRIPTION OF THE RELATED ART 
     Generally, of the components forming the refrigeration cycle in an air conditioner for vehicles, the evaporator is placed inside the passenger room, and others such as the compressor and the like are placed inside the engine room. The refrigeration cycle is provided with a thermal expansion valve for controlling the amount of refrigerant entering the evaporator. 
     FIG. 26 is a vertical cross-sectional view showing the state where a box-type expansion valve conventionally used as an expansion valve is placed in the refrigeration cycle of the air conditioner used for a vehicle, and FIG. 27 is a schematic perspective view of the same. In FIG. 26, an expansion valve  10  is formed of a prismatic valve body  30  made from aluminum and the like, a first passage  32  through which refrigerant travels from a condenser  5  via a receiver  6  to an evaporator  8  in a refrigeration cycle  11 , and a second passage  34  through which refrigerant travels from the evaporator  8  to a compressor  4 , both passages being formed on the valve body  30  and placed vertically apart from each other. Also, the expansion valve  10  includes an orifice  32   a  and a valve chamber  35  provided to the first passage  32 , a spherical valve means  32   b  provided to the upstream side of the passage  32  for controlling the amount of refrigerant traveling through the orifice  32   a , and an adjust screw  39  for a spring  32   d  providing pressure to the valve means  32   b  in the direction toward the orifice  32   a  through a valve member  32   c . The adjust screw  39  having a screw portion  39   f  is screwed retrievably to a mount hole  30   a  connecting to the valve chamber  35  of the first passage  32  from the lower end surface of the valve body  30 , and an O-ring  39   g  is mounted to the adjust screw  39  so as to secure airtightness of the valve body  30 . The opening of the valve means  32   d  to the orifice  32   a  is adjusted by the adjust screw  39  and the pressure spring  32   d.    
     Reference number  321  is an entrance port where refrigerant exiting the receiver  6  and traveling toward the evaporator  8  enters. The entrance port  321  is connected to the valve chamber  35 , and reference number  322  is an exit port of the refrigerant flowing into the evaporator  8 . Also, reference number  50  of FIG. 27 shows bolt holes for mounting the expansion valve, and the lower portion of the valve body  30  is thinned. A small-diameter aperture  37  for opening and closing the orifice  32   a  by providing driving force to the valve means  32   b  corresponding to the exit temperature of the evaporator  8 , and an aperture  38  having a larger diameter than the aperture  37  are provided to the valve body  30  coaxial to the orifice  32   a . A screw hole  361  for fixing the power element portion  36  as a heat sensing portion is provided to the upper end of the valve body  30 . 
     The power element portion  36  constitutes a diaphragm  36   a  made of stainless steel and the like, and an upper pressure working chamber  36   b  and a lower pressure working chamber  36   c  formed coherent to each other by welding while interposing the diaphragm  36   a , forming two airtight heat sensing chambers above and below the diaphragm  36   a . The power element portion  36  is equipped with an upper lid  36   d  and a lower lid  36   h  made of stainless steel and the like, and a plug body  36   k  for enclosing predetermined refrigerant acting as a diaphragm driving fluid to the upper pressure working chamber  36   b , and the lower lid  36   h  is screwed into a screw hole  361  through a packing  40 . The lower pressure working chamber  36   c  is connected to the second passage  34  through an equalizing hole  36   e  formed concentric with the center line of the orifice  32   a . Refrigerant from the evaporator  8  travels through the second passage  34 , and the passage  34  becomes the passage for vapor refrigerant, and the pressure of the refrigerant is loaded to the lower pressure working chamber  36   c  through the pressure equalizing hole  36   e . Reference number  342  is an entrance port where refrigerant exiting the evaporator  8  enters, and  341  is an exit port where refrigerant discharged to the compressor  4  exits. 
     Also, a peak portion  312  formed in a large-diameter saucer which comes into contact with the central portion of the lower surface of the diaphragm  36   a  is provided inside the lower pressure working chamber  36   c . The power element portion  36  is further comprised of a heat sensing shaft  36   f  made of aluminum which pierces through the second passage  34  and is arranged slidably inside the large-diameter aperture  38  to transmit the temperature at the refrigerant exit of the evaporator  8  to the lower pressure working chamber  36   c  and which provides driving force by sliding inside the large-diameter aperture  38  corresponding to the displacement of the diaphragm  36   a  based on the difference in pressure between the upper pressure working chamber  36   b  and the lower pressure working chamber  36   c , and a working shaft  37   f  made of stainless steel and having a smaller diameter than the heat sensing shaft  36   f  which is arranged slidably inside the small-diameter aperture  37  to provide pressure to the valve means  32   b  resisting to the elastic force of the spring means  32   d  corresponding to the displacement of the heat sensing shaft  36   f . The upper end portion of the heat sensing shaft  36   f  is composed from a peak portion  312  as a receiving portion of the diaphragm  36   a  and a large-diameter portion  314  sliding inside the lower pressure working chamber  36   c , and the lower end portion of the heat sensing shaft  36   f  comes into contact with the upper end portion of the working shaft  37   f , the lower end portion of the working shaft  37   f  comes into contact with the valve means  32   b , so that the heat sensing shaft  36   f  and the working shaft  37   f  constitute altogether the valve means driving shaft  318 . The peak portion  312  and the large-diameter portion  314  may be formed as one member. 
     That is, the valve means driving shaft  318  extending from the lower surface of the diaphragm  36   a  to the orifice  32   a  of the first passage  32  is concentrically arranged in the equalizing hole  36   e . The portion  37   e  of the working shaft  37   f  having in a diameter smaller than the inner diameter of the orifice  32   a  pierces through the orifice  32   a , and the refrigerant passes inside the orifice  32   a . Also, an O-ring  36   g  is provided to the heat sensing shaft  36   f  in order to secure airtightness of the first passage  32  and the second passage  34 . 
     A known diaphragm driving fluid is filled inside the upper pressure working chamber  36   b  of the pressure working housing  36   d , and the heat of the refrigerant at the refrigerant exit of the evaporator  8  traveling inside the second passage  34  is transmitted to the diaphragm driving fluid through the diaphragm  36   a  and the valve means driving shaft  318  exposed to the second passage  34  or the equalizing hole  36   e  connected to the second passage  34 . 
     The diaphragm driving liquid inside the upper pressure working chamber  36   b  turns into gas corresponding to the above-mentioned transmitted heat, and loads pressure to the upper surface of the diaphragm  36   a . The diaphragm  36   a  is displaced vertically by the difference in the above-mentioned pressure of the diaphragm driving gas loaded to the upper surface and the pressure loaded to the lower side of the diaphragm  36   a.    
     The vertical displacement of the central portion of the diaphragm  36   a  is transmitted to the valve means  32   b  through the valve means driving shaft, and moves the valve means  32   b  closer to or away from the valve seat of the orifice  32   a . As a result, the flow rate of the refrigerant is controlled. 
     Namely, the temperature of the low-pressure vapor refrigerant at the exit side of the evaporator  8 , that is, refrigerant exiting the evaporator, is transmitted to the upper pressure working chamber  36   b , so that the pressure within the upper pressure working chamber  36   b  changes corresponding to the transmitted temperature, and the exit temperature of the evaporator  8  rises. When the heat load of the evaporator increases, the pressure within the upper pressure working chamber  86   b  increases, and the heat sensing shaft  36   f , that is the valve means driving shaft, is driven downward moving the valve body  32   b  downwards, so that the opening of the orifice  32   a  increases. With such movement, the supply of refrigerant to the evaporator  8  increases, and lowers the temperature of the evaporator  8 . On the contrary, when the temperature of the refrigerant exiting the evaporator  8  drops, that is, when the heat load of the evaporator decreases, the valve means  32   b  is driven in the opposite direction, decreasing the opening of the orifice  32   a , decreasing the supply of the refrigerant to the evaporator, so that the temperature of the evaporator  8  rises. 
     In such conventional thermal expansion valve, the heat sensing shaft  36   f  is a member having relatively large diameter, and such member and the working shaft constitute the valve means driving shaft. However, there is a conventional thermal expansion valve constituting the above-mentioned valve means driving shaft with a rod member, and such conventional thermal expansion valve  10 ′ using the rod member is shown in FIG.  28 . The operation of the expansion valve shown in FIG. 28 is the same as the expansion valve shown in FIG. 26 or  27 , and the same reference numbers with FIG. 26 or  27  indicate the same or equal portions. 
     A heat sensing portion  318  having a heat sensing mechanism operates as the heat sensing shaft  361   f , comprising a large-diameter stopper  312  to the surface of which the diaphragm  36   a  contacts and acts as a receiving portion of the diaphragm  36   a , a large-diameter portion  314  having one end surface adjoining the rear surface of the stopper  312  and having the central portion of the other end constituted as a projection  315  which is inserted slidably inside the lower pressure working chamber  36   c , and a rodmember  316  of continuous integral composition with one end surface of which embedded to the interior of the projection  315  of the large-diameter portion  314  and the other end connected to the valve means  32   b  through a portion  371  corresponding to the working shaft. The heat sensing shaft  361   f  constituting the rod member  316  is exposed inside the second passage and the heat from the refrigerant vapor is transmitted thereto. 
     The rod member  361  which is a heat sensing shaft  361   f  is driven to move back and forth across the passage  34  corresponding to the displacement of the diaphragm  36   a  of the power element portion  36 , so that a clearance connecting the passage  32  and the passage  34  is formed along the rod portion  316 . In order to prevent formation of such clearance, an O-ring  42  fitted tightly to the outer circumference of the rod portion  316  is placed inside the large-diameter aperture  38 ′ so that the O-ring exists between the passages. Moreover, in order to prevent the O-ring  42  from moving by the force operating in the longitudinal direction (the direction towards the power element portion  36 ) provided by the coil spring  32   d  and the refrigerant pressure of the passage  321 , a push nut  41  as a self-locking nut is mounted to the rod portion  316 , positioned inside the large-diameter aperture  38 ′ and contacting the O-ring  42 . 
     Such positioning and supporting structure of the conventional thermal expansion valve has been variously proposed. That is, a composition where an opening is provided on the division separating the engine room and the passenger room, and placing the thermal expansion valve to the passenger room side of the opening, connecting the refrigerant piping providing the refrigerant to the evaporator to the thermal expansion valve through a block-like connector, and supporting the above-mentioned connector through a packing material to the above-mentioned opening (for example, gazette of Japanese Patent Laid-Open 223427/95 and Japanese Utility Model Laid-Open 37729/95) has been proposed. 
     Also, a structure where the thermal expansion valve itself is supported to the opening through the packing material (for example, refer to the gazette of Japanese Patent Laid-Open 215047/95) has been proposed. 
     SUMMARY OF THE INVENTION 
     However, in such a supporting structure of the thermal expansion valve mentioned above, it is uneconomical in view of component cost and assembly cost to use the connector and the packing. Also, in the case where the thermal expansion valve is supported directly through the packing material, there is a problem that a clearance may be formed between the inner wall of said opening and the thermal expansion valve resulting in insufficient sealing. Moreover, in a conventional thermal expansion valve, the shape for supporting the thermal expansion valve of the air conditioner of an automobile to the opening of said division has never been considered. That is, the upper lid constituting the power element portion of the thermal expansion valve is formed as a dome provided with a cork body projecting from the wall portion of the upper lid so that ability to fit tightly with said inner wall of the opening becomes a problem, and the outer shape of the power element portion has not been considered. 
     Therefore, the present invention aims at providing a thermal expansion valve that could be tightly fixed to the opening provided to the division dividing the engine room and the passenger room, providing a secure seal. 
     In order to achieve the above-mentioned object, the thermal expansion valve of the present invention is comprised of a valve body, a power element portion provided to the upper end portion of said valve body which drives a valve means according to the displacement of a diaphragm, and an adjust screw provided to the lower end portion of said valve body which adjusts the pressurizing force of a spring controlling the valve opening of said valve means, wherein said power element portion is provided with a cover embracing the same, and the lower portion of said valve body is formed as a tapered surface. 
     Also, the thermal expansion valve of the present invention is comprised of a valve body equipped with a first passage through which refrigerant entering an evaporator travels and a second passage through which refrigerant exiting from said evaporator travels, the opening of a valve being controlled both by a valve means arranged opposing an orifice formed partway of said first passage and being biased toward the valve closing direction with a spring, and by a power element operated by sensing the temperature of said refrigerant traveling through said second passage and forcing said valve means toward the valve opening direction through a rod, wherein said power element is provided with a cover embracing the same, and the lower portion of said valve body provided with said spring is formed as a tapered surface. 
     Moreover, as a preferable embodiment of the thermal expansion valve of the present invention, the cover includes an interior formed with a concave portion and an exterior formed with curvature surfaces and tapered surfaces continuing therefrom, said concave portion storing the power element therein, and said tapered surfaces being substantially continued from the tapered surfaces of said valve body. 
     Further, as an embodiment of the thermal expansion valve of the present invention, the tapered surfaces of said valve body are formed from substantially the middle of the total height of said valve body. 
     Also, as an embodiment of the thermal expansion valve of the present invention, the valve body is formed to have an outer shape comprising mutually parallel surfaces starting from the upper surface provided with said power element portion and extended to approximately the middle of the total height of said valve body, and tapered surfaces continued therefrom which is tapered toward a bottom surface provided with an adjust screw. 
     According to the present invention being formed as explained above, the valve body is formed with parallel surfaces and tapered surfaces, enabling the valve body to fit tightly to the above-mentioned division wall, and improving the fixing capability. 
     Moreover, it could change the outer shape of the power element portion with the cover provided to the power element portion, and the fitting with the opening of the above-mentioned division wall is improved, and also the sealing ability is improved. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front view of the thermal expansion valve of the present invention; 
     FIG. 2 is a left side view of the thermal expansion valve of the present invention; 
     FIG. 3 is a right side view of the thermal expansion valve of the present invention; 
     FIG. 4 is a rear view of the thermal expansion valve of the present invention; 
     FIG. 5 is a top view of the thermal expansion valve of the present invention; 
     FIG. 6 is a bottom view of the thermal expansion valve of the present invention; 
     FIG. 7 is a front view of the thermal expansion valve with a cover; 
     FIG. 8 is a left side view of the thermal expansion valve with a cover; 
     FIG. 9 is a right side view of the thermal expansion valve with a cover; 
     FIG. 10 is a rear view of the thermal expansion valve with a cover; 
     FIG. 11 is a top view of the thermal expansion valve with a cover; 
     FIG. 12 is a bottom view of the thermal expansion valve with a cover; 
     FIG. 13 is a perspective view of the cover of the thermal expansion valve; 
     FIG. 14 is a side view showing the mounted state of the thermal expansion valve of the present invention; 
     FIG. 15 is a front view showing the mounted state of the thermal expansion valve of the present invention; 
     FIG. 16 is a front view of the thermal expansion valve of another embodiment of the present invention.; 
     FIG. 17 is a left side view of the thermal expansion valve of another embodiment of the present invention; 
     FIG. 18 is a right side view of the thermal expansion valve of another embodiment of the present invention; 
     FIG. 19 is a rear view of the thermal expansion valve of another embodiment of the present invention; 
     FIG. 20 is a top view of the thermal expansion valve of another embodiment of the present invention; 
     FIG. 21 is a bottom view of the thermal expansion valve of another embodiment of the present invention; 
     FIG. 22 is a perspective view of the cover of the thermal expansion valve; 
     FIG. 23 is a perspective view of the cover of the thermal expansion valve; 
     FIG. 24 is a side view showing the mounted state of the conventional thermal expansion valve; 
     FIG. 25 is a front view showing the mounted state of the conventional thermal expansion valve; 
     FIG. 26 is a longitudinal cross-sectional view of the conventional thermal expansion valve; 
     FIG. 27 is a schematic perspective view of another example of the conventional thermal expansion valve; and 
     FIG. 28 is a cross-sectional view of another example of the conventional thermal expansion valve. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     FIGS. 1 through 6 are drawings indicating one embodiment of the thermal expansion valve of the present invention, in which FIG. 1 is a front view, FIG. 2 is a left side view, FIG. 3 is a right side view, FIG. 4 is a rear view, FIG. 5 is a top view, and FIG. 6 is a bottom view. 
     The present invention provides the identical function as the conventional thermal expansion valve, and differs from the conventional thermal expansion valve only in the outer shape of the valve body. Therefore, the same reference numbers will be provided to the identical portions, and explanations on portions explained in the explanation of conventional valve are omitted. 
     The thermal expansion valve shown as a whole by reference number  100  has a valve body  110  made from aluminum alloy and the like. A power element portion  36  explained above is mounted to the peak portion of the valve body  110 , and the diaphragm inside the power element portion  36  operates a heat sensing shaft  361   f.    
     To one side near a bottom  116  of the valve body  110  is provided an entrance port  321  of a first passage  32  of the refrigerant supplied through a condenser and a receiver. The refrigerant thus introduced travels to an evaporator from an exit port  322  provided to the other side of the valve body through an orifice, the opening of which is adjusted by the heat sensing shaft  361   f.    
     The refrigerant exiting the evaporator travels through a second passage  34  provided to a power element portion  36  side of the valve body  110 . During the course, the temperature of the refrigerant is transmitted to the diaphragm through the heat sensing shaft  361   f.    
     The valve body  110  is provided with two perforation holes  50  in parallel to the axis of the second passage  34 . The perforation holes are used to pierce rods and the like to fasten the body to other members. Also, to the other side of the valve body  110 , a screw hole  152  is provided with a bottom in parallel to the perforation hole  50 , and a screwing bolt and the like is screwed thereto. 
     Sides  112  in parallel to the axis of a refrigerant passage  140  of the valve body  110  are construed of surfaces in parallel with each other from the top surface mounted with the power element portion  36  towards the bottom surface  116  until approximately the middle of the total height of the valve body  110 . From the middle of the body to the bottom surface  116 , the sides are formed as tapered surfaces  114  continuing from the parallel surfaces. 
     To the bottom surface  116  of the valve body  110  is mounted a nut member  39  for sealing the valve chamber explained before. 
     With the thermal expansion valve of the present invention, the valve body is comprised of parallel surfaces and tapered surfaces continuing from the parallel surfaces, so that it is easily fitted tightly to the division mentioned above, and the mounting ability is improved. 
     Next, an embodiment of the present invention where the thermal expansion valve of the present invention is mounted to said division will be explained. 
     FIG. 7 is a front view of the thermal expansion valve indicating the state where the cover is mounted to the outer side of the valve body of the thermal expansion valve shown in the embodiment of FIGS. 1 through 6, FIG. 8 is a left side view, FIG. 9 is a right side view, FIG. 10 is a rear view, FIG. 11 is a top view, and FIG. 12 is a bottom view, each corresponding to FIGS. 1 through 6. 
     A cover shown as a whole by reference number  200  in the figure is formed from plastic resin and the like. 
     The cover  200  is provided with a head portion  220  having a concave portion  221  formed therein for storing the power element portion  36 , and a tapered portion  210  covering the outer side of the parallel sides of the thermal expansion valve  110 . The concave portion  221  stores the power element portion  36 , and contacts the outer peripheral of the power element portion  36 . Therefore, with the cover  200 , the outer shape of the power element portion  36  is adjusted. Outer sides  212  of the tapered portion  210  are formed as tapered surfaces forming approximately identical planes with the tapered surfaces  114  of the valve body  110  of the thermal expansion valve. Inner sides  214  of the tapered portion  210  are embedded to the parallel surface of the valve body  110 . 
     Outer surfaces  222  of the head portion  220  of the cover  200  are composed of curved surfaces. 
     Therefore, the thermal expansion valve mounted with the cover  200  has the side shape as is indicated in FIGS. 8 and 9. 
     Also, end surface  224  of the head portion  220  as seen from the front projects from the expansion valve body, and covers the entire power element portion  36 . The end surface  224  contacts with the expansion valve body with surface  226  orthogonal to the end surface  224 . As seen from above, the thermal expansion valve of the present invention is construed so as to have an outer shape formed from outer surfaces of the curved surfaces and the tapered surfaces, and the fitting of the thermal expansion valve and the mounting portion is improved. 
     FIG. 13 is a cross-sectional view of the cover  200 . The cover  200  is, for example divided into two parts, and is mounted to the thermal expansion valve. The divided surfaces are fixed with proper methods such as adhesive or fastener and the like. With the cover  200 , the power element is inserted to its concave portion and the outer peripheral of the power element is contacted thereto, so the sealing ability of the cover and the thermal expansion valve is improved, and also the mounting ability is improved. 
     FIG. 14 is a side view showing the condition where the thermal expansion valve of the present invention is mounted, for example, to an opening  501  formed at a division  500  dividing the engine room and the passenger room of an automobile, and FIG. 15 is a front view. 
     The thermal expansion valve  100  with the cover  200  is held to the opening  501  which is the mounting portion formed to the division  500  made from metal board through a seal member  510  which is a packing member. Pipings  600 ,  610  of the refrigerant are connected to the body of the thermal expansion valve with brackets  620 . 
     The front shape of the thermal expansion valve mounted with the cover  200  has a shape substantially covered with the tapered surfaces and the curved surfaces, so that fitting of the seal member  510  to the opening which is a mounting portion is improved, and the opening is sealed effectively. 
     Therefore, the engine room and the passenger room are sealed completely. 
     The above explanations were given regarding cases where the cover  400  is divided and mounted to the thermal expansion valve  100 . However, the present invention is not limited to such case, and could be applied to cases where the cover formed as a single body from plastic resin and the like is mounted to the thermal expansion valve. 
     FIGS. 16 through 23 show another embodiment of the present invention for such case, wherein the composition of the thermal expansion valve is the same as that shown in FIGS. 1 through 6, and so identical portions are provided with identical reference numbers and explanations thereof are omitted. 
     That is, FIG. 16 is a front view of the thermal expansion valve showing the embodiment where the cover is mounted to the thermal expansion valve  100 , FIG. 17 is a left side view, FIG. 18 is a right side view, FIG. 19 is a rear view, FIG. 20 is a top view, FIG. 21 is a bottom view, FIG. 22 is a perspective view of the cover, and FIG. 23 is a perspective view of the cover observed from the direction of arrow R in FIG.  22 . 
     In the figures, the cover indicated as a whole by reference number  400  is formed as a single body from plastic resin and the like. 
     A body  410  of the cover  400  has double side portions  412  and a head portion  422 , wherein the outer surface of the double side portions  412  are formed as tapered surface and the inner surfaces thereof are formed as plane surfaces  414  contacting the body of the thermal expansion valve  100 . The outer surface of the head portion  422  is formed as a curved surface, and concave portions  424 ,  426  for storing the power element portion  36  of the thermal expansion valve are formed to the interior thereof. The power element portion  36  is inserted along the concave portions  424  and  426 , and the cover  400  is mounted to the thermal expansion valve  100 . 
     The depth size of the concave portions  424  and  426  are selected considering the position for storing the power element portion  36  when the cover  400  is mounted over the power element portion  36 . 
     A plurality of projecting portions  416  is formed at the rear end of the inner surface  414  of the double side portion  412  of the cover body  410 . When the cover  400  is mounted to the thermal expansion valve  100 , the expansion valve body  110  is stopped against the projecting portions  416  and is positioned thereto. 
     A plurality of arcuate notches  418  is formed to the lower end of the projecting portion  416 . The notches  418  are provided to avoid the interference of the bolt holes  50  for mounting provided to the thermal expansion valve body  110 . 
     Moreover, in the cover  400  shown in FIGS. 22 and 23, projecting portion of the end side  224  formed in the cover  200  of FIG. 13 is omitted, and one portion of the power element portion  36 , as is shown in FIG. 16, is exposed from the concave portion  426 . 
     FIG. 24 is a side view showing the state where the thermal expansion valve  100  equipped with the cover  400  is mounted, for example, to an opening formed at a division  500  dividing the engine room and the passenger room of an automobile, and FIG. 25 is a front view thereof. The composition is the same as that explained for FIGS. 14 and 15, therefore identical portions are given identical reference numbers and explanations thereof are omitted. 
     As seen from above, the present invention enables to adjust the shape of the outer peripheral of the power element portion by covering the thermal expansion valve used in the refrigeration cycle for a car air conditioner and the like with a cover. Therefore, the present invention provides a thermal expansion valve having secure and good seal ability when fixing the thermal expansion valve to the division between the engine room and the passenger room of an automobile and the like.