Patent Publication Number: US-2020293071-A1

Title: Thermostatic valve

Description:
The application claims the priorities to Chinese patent application No. 201711116965.7 titled “THERMOSTATIC VALVE”, filed with the China National Intellectual Property Administration on Nov. 13, 2017 and Chinese patent application No. 201711115307.6, titled “THERMOSTATIC VALVE”, filed with the China National Intellectual Property Administration on Nov. 13, 2017, both of which are incorporated herein by reference in their entireties. 
     FIELD 
     The present application relates to the technical field of valve bodies, and in particular to a thermostatic valve. 
     BACKGROUND 
     Lubricating oil should be accommodated in a transmission of a vehicle, which can perform functions of lubrication and cooling, and the lubricating oil is required to be controlled at an appropriate working temperature. 
     When the temperature of the lubricating oil in the transmission is high, it can be cooled by an external cooling device. The cooling device includes a heat exchanger, which uses cooling water or refrigerant to cool the lubricating oil with a higher temperature, so as to achieve the purpose of keeping the lubricating oil of the transmission within a certain working temperature range. When the temperature of the lubricating oil is low, the lubricating oil does not pass through the cooling device, that is, when the lubricating oil of the transmission flows out, there are two flow paths, one flow path is through the cooling device, and the other is not through the cooling device. 
     At present, the switching of the above two flow paths is performed through a thermostatic valve. The thermostatic valve is provided with a thermal actuator and a spring. The thermal actuator thermally expands and contracts according to the temperature of the fluid sensed by the thermosensitive substance. During the thermal expansion, a force is transmitted to the spring, the flow path through the cooling device is opened; and during the cold contraction, the spring is reset, and the flow path through the cooling device is bypassed. 
     However, the above solution has the following technical problems. 
     There is a certain response time required from sensing temperature by the thermosensitive substance to the thermal expansion and contraction process then to applying the force on the spring, that is, the response time of the thermal actuator is long, which will cause a certain hysteresis of the temperature of the lubricating oil, and then affect the performance of the transmission. In addition, the thermal actuator including the above thermosensitive substance has a large volume. 
     SUMMARY 
     A thermostatic valve is provided according to the present application, to improve the sensing time of the temperature control. 
     A thermostatic valve is provided according to the present technical solution, which includes an end cover, a valve body, and a valve core located in a valve cavity of the valve body, wherein the thermostatic valve has a first outlet, a second outlet, and a first inlet in communication with the valve cavity, the valve body is further provided with a first valve port which is configured to communicate the valve cavity with the second outlet, and during a movement of the valve core, the valve core is configured to open or close the first valve port; wherein 
     a return spring and a memory spring are further provided in the valve cavity, the memory spring is made of a memory alloy; the return spring is configured to provide a return force allowing the valve core to open the first valve port; the memory spring has one end in contact with one end of the valve core, and another end in contact with the end cover, and when a temperature rises to a specified value, the memory spring is configured to generate an elastic force to drive the valve core to move against the return force to close the first valve port; and 
     at least a portion of an outer wall of the valve core is in sliding fit with an inner wall of the valve cavity, and the first inlet is provided in a side wall of the valve body. 
     Compared with the technical solution with the thermal actuator, the response time of the solution using the memory spring is faster and the first valve port can be opened in time to switch the medium to another flow path in the above technical solution. When being applied to coolers and transmissions, it can improve the performance of the transmission. Moreover, compared with the thermal actuator, the combination of the memory spring and the valve core is lighter in weight and smaller in volume. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view showing the structure of a thermostatic valve according to a first embodiment of the present application; 
         FIG. 2  is a schematic view of the thermostatic valve in  FIG. 1  viewed at another angle, showing the bottom; 
         FIG. 3  is a sectional view of the thermostatic valve in  FIG. 1 , with a second valve port closed and a first valve port opened; 
         FIG. 4  is a schematic view of the thermostatic valve in  FIG. 3  after the valve core is moved to the right, with the first valve port closed and the second valve port opened; 
         FIG. 5  is a schematic view of the valve body in  FIG. 3 ; 
         FIG. 6  is a sectional view showing the structure of a thermostatic valve according to a second embodiment of the present application, with a second valve port closed and a first valve port opened; 
         FIG. 7  is a schematic view of the thermostatic valve in  FIG. 6  after the valve core is moved to the right, with the first valve port closed and the second valve port opened; 
         FIG. 8  is a sectional view showing the structure of a thermostatic valve in an initial state according to a third embodiment of the present application, with a first valve port having a preset opening degree and a second valve port having a preset opening degree; 
         FIG. 9  is a schematic view of the thermostatic valve in  FIG. 8  after the temperature rises to a specified value and a memory spring is deformed, with the first valve port closed and the second valve port opened; 
         FIG. 10  is a schematic view of the thermostatic valve in  FIG. 9  after the temperature drops below a specified value and the memory spring loses characteristics, with the first valve port opened and the second valve port closed; 
         FIG. 11  is a schematic view showing the structure of a valve core in  FIG. 8 ; 
         FIG. 12  is a sectional view showing the structure of a thermostatic valve in an initial state according to a forth embodiment of the present application, with a first valve port having a preset opening degree and a second valve port having a preset opening degree; 
         FIG. 13  is a schematic view of the thermostatic valve in  FIG. 12  after the temperature rises to a specified value and a memory spring is deformed, with the first valve port closed and the second valve port opened; 
         FIG. 14  is a schematic view of the thermostatic valve in  FIG. 13  after the temperature drops below a specified value and the memory spring loses characteristics, with the first valve port opened and the second valve port closed; 
         FIG. 15  is a schematic view showing the structure of an end cover in  FIG. 12 ; 
         FIG. 16  is a sectional view showing the structure of a thermostatic valve in an initial state according to a fifth embodiment of the present application, with a first valve port having a preset opening degree and a second valve port having a preset opening degree; 
         FIG. 17  is a schematic view of the thermostatic valve in  FIG. 16  after the temperature rises to a specified value and a memory spring is deformed, with the first valve port closed and the second valve port opened: 
         FIG. 18  is a schematic view of the thermostatic valve in  FIG. 17  after the temperature drops below a specified value and the memory spring loses characteristics, with the first valve port opened and the second valve port closed; 
         FIG. 19  is a sectional view showing the structure of a thermostatic valve according to a sixth embodiment of the present application, with a first valve port closed and a second valve port opened; 
         FIG. 20  is a schematic view showing the structure of a valve core in  FIG. 19 ; 
         FIG. 21  is a sectional view showing the structure of a thermostatic valve according to a seventh embodiment of the present application, with a first valve port closed and a second valve port opened; 
         FIG. 22  is a sectional view showing the structure of a thermostatic valve according to an eighth embodiment of the present application, with a first valve port opened and a second valve port closed; 
         FIG. 23  is a schematic view of the thermostatic valve in  FIG. 22  after the temperature rises and a memory spring is deformed, with the first valve port closed and the second valve port opened; 
         FIG. 24  is a schematic view showing an end cover, a valve core, a return spring, and the memory spring in  FIG. 22  after installation; 
         FIG. 25  is a schematic perspective view of  FIG. 24 ; 
         FIG. 26  is a sectional view showing the structure of a thermostatic valve according to a ninth embodiment of the present application, with a first valve port B closed and a second valve port A opened; 
         FIG. 27  is a sectional view showing the structure of a thermostatic valve according to a tenth embodiment of the present application, with a first valve port opened and a second valve port closed; 
         FIG. 28  is a schematic view of the thermostatic valve in  FIG. 27  after a valve core is moved to the right, with the second valve port opened and the first valve port closed; and 
         FIG. 29  is a schematic view of the valve core in  FIG. 27 . 
     
    
    
     REFERENCE NUMERALS IN FIGS.  1  TO  29   
       
     
       
         
           
               
               
               
               
             
               
                   
               
             
            
               
                  10 
                 valve body, 
                  10a 
                 valve cavity, 
               
               
                  10b 
                 linear passage, 
                  10c 
                 small hole, 
               
               
                  10d 
                 outlet passage, 
                  10e 
                 inlet passage, 
               
               
                 B 
                 first valve port, 
                 A 
                 second valve port; 
               
               
                 101 
                 first outlet, 
                 102 
                 second inlet, 
               
               
                 103 
                 first inlet, 
                 104 
                 second outlet, 
               
               
                 201 
                 memory spring, 
                 202 
                 return spring, 
               
               
                  30 
                 end cover, 
                 301 
                 first stepped surface, 
               
               
                 302 
                 second stepped surface, 
               
               
                  40 
                 valve core, 
                 401 
                 main body portion, 
               
               
                  401a 
                 end protruding platform, 
                 402 
                 sleeve portion, 
               
               
                  402a 
                 guiding inlet, 
                  402b 
                 opening, 
               
               
                  402c 
                 notch, 
                 403 
                 guide rod, 
               
               
                 405 
                 sealing plate, 
                  405a 
                 recessed hole, 
               
               
                 404 
                 spherical portion, 
                     40′ 
                 sealing piece, 
               
               
                  50 
                 external connector, 
                  60 
                 valve stem. 
               
               
                   
               
            
           
         
       
     
     DETAILED DESCRIPTION 
     In order to make those skilled in the art to better understand the technical solutions of the present application, the present application is further described in detail below in conjunction with the drawings and specific embodiments. 
     Referring to  FIGS. 1 to 4 ,  FIG. 1  is a schematic view showing the structure of a thermostatic valve according to a first embodiment of the present application;  FIG. 2  is a schematic view of the thermostatic valve in  FIG. 1  viewed at another angle, showing the bottom;  FIG. 3  is a sectional view of the thermostatic valve in  FIG. 1 , with a second valve port closed and a first valve port opened;  FIG. 4  is a schematic view of the thermostatic valve in  FIG. 3  after a valve core is moved to the right, with the first valve port closed and the second valve port opened; and  FIG. 5  is a schematic view of a valve body in  FIG. 3 . 
     The thermostatic valve according to the first embodiment includes a valve body  10 , and a valve cavity  10   a  is formed inside the valve body. Specifically, in this embodiment, as shown in  FIGS. 3 and 5 , the valve cavity  10   a  penetrates one end surface of the valve body  10  from left to right, to form the valve cavity  10   a  with an end port at the left end, and an end cover  30  is used to block the end port. A valve core  40  is provided in the valve cavity  10   a , and the valve core  40  can move axially along the valve cavity  10   a . The axial direction here refers to an extending direction of the valve cavity  10   a  from one end to the other end, which is the left-right direction shown in  FIGS. 3 and 4 . When the valve body  10  is in the rectangular parallelepiped shape as shown in  FIGS. 1 and 2 , the axial direction here also refers to the length direction of the valve body  10  or the length direction of the valve cavity  10   a.    
     The thermostatic valve has a first outlet  101 , a second inlet  102  and a second outlet  104 , and also has a first inlet  103  in communication with the valve cavity  10   a . In this embodiment, the above inlets and outlets are integrally formed in an outer wall of the valve body  10 , which can be connected to external members. In  FIG. 5 , a first valve port B for communicating the valve cavity  10   a  with the second outlet  104  and a second valve port A for communicating the valve cavity  10   a  with the first outlet  101  are also provided in the valve body  10 . The second valve port A is specifically provided in a side cavity wall of the valve cavity  10   a , and an outlet passage  10   d  is formed between the second valve port A and the first outlet  101 . The first valve port B is formed in an end cavity wall of the valve cavity  10   a , that is, the cavity wall at the right end in  FIG. 3 , and the left end is the end port blocked by the end cover  30 . The first valve port B is in communication with the second outlet  104  through the second outlet passage, and the second outlet passage in  FIG. 3  includes a small hole  10   c , and a linear passage  10   b  between the second inlet  102  and the second outlet  104 . 
     The thermostatic valve according to all the embodiments herein can be used between a transmission and a cooler. The medium flowing inside the thermostatic valve is lubricating oil. That is, the first outlet  101  of the thermostatic valve is in communication with an inlet of the cooler, the second inlet  102  is in communication with an outlet of the cooler, the second outlet  104  is in communication with an inlet of the transmission, and the first inlet  103  is in communication with an outlet of the transmission. After flowing out of the transmission, the lubricating oil enters the thermostatic valve through the first inlet  103 , and then the lubricating oil flows directly back to the transmission through the first port B and the second outlet  104 , or the lubricating oil enters the cooler through the second port A and the first outlet  101  to be cooled, and returns to the transmission through the second inlet  102  and the second outlet  104 . The following main working process is also exemplified by this application. However, it can be understood that the transmission and the cooler are only a typical application of the thermostatic valve in the present application. Obviously, besides the transmission, the thermostatic valve can also be applied to other applications that are required to control temperature to adjust the medium flow path. 
     Specifically, the valve core  40  in this embodiment is movable to switch the opening and closing of the first valve port B and the second valve port A. As shown in  FIG. 3 , the valve core  40  can move right to block the first valve port B and open the second valve port A; and the valve core  40  can move left to block the second valve port A and open the first valve port B. The opening and closing of the first valve port B and the second valve port A realize the switching of the two flow paths; and when the thermostatic valve is applied to the transmission and the cooler, the lubricating oil can be cooled by passing through the cooler or can directly return to the transmission without cooling. 
     The movement of the valve core  40  is mainly achieved by a return spring  202  and a memory spring  201  provided in the valve cavity  10   a . The memory spring  201  is a spring made of a shape memory alloy material (SMA: Shape Memory Alloy). The return spring  202  can provide a return force that causes the valve core  40  to open the first valve port B. In this embodiment, the return spring  202  is a tension spring, that is, it provides a pulling force. The direction of the pulling force of the valve core  40  in  FIG. 3  is leftward. The leftward spring can play the role of connecting the valve core  40 . The valve core  40  can be processed into a structure with an I-shaped axial cross section as shown in the figure, to reduce weight and facilitate movement. When the temperature rises to a specified value, the elastic characteristic of the memory spring  201  is activated, and the memory spring  201  has an elastic potential energy to provide the elastic force. The direction of the elastic force is opposite to the direction of the pulling force to drive the valve core  40  to move against the return force. The specified value corresponding to the elasticity of the memory spring  201  being activated can be determined by selecting materials according to the requirement, so that the memory spring  201  can be deformed due to increased temperature at the ambient temperature where the path switching is required. 
     The following working principle of this embodiment is described as follows. 
     In the working state shown in  FIG. 3 , the medium (for example, the above lubricating oil of the transmission) flows from the first inlet  103  into the valve cavity  10   a  of the thermostatic valve. Since the second valve port A is closed and the first valve port B is opened, the medium flows to the small hole  10   c , the linear passage  10   b , and the second outlet  104  through the first valve port B, and returns to the transmission. 
     When the medium temperature rises to a specified value, the thermostatic valve is in the working state shown in  FIG. 4 , the elastic characteristic of the memory spring  201  is activated, and the elastic force generated is greater than the return force of the return spring  202 . At this time, the valve core  40  moves toward the first valve port B under a difference between forces applied by the memory spring  201  and the return spring  202 . The valve core  40  can block the first valve port B and open the second valve port A. After the medium flows in from the first inlet  103 , the medium enters the cooler through the second valve port A, the outlet passage  10   d , and the first outlet  101 , to be cooled. The cooled lubricating oil flows out of the cooler, and then enters the valve cavity  10   a  from the second inlet  102 , and re-enters the transmission through the linear passage  10   b  and the second outlet  104 . 
     After the temperature of the medium drops below a specified value, the elastic characteristic of the memory spring  201  fails, the elastic force decreases and then disappears, and the valve core  40  moves away from the first valve port B under the return force of the return spring  202 , and at this time, the first valve port B is opened, the second valve port A is closed and the valve core  40  returns to the state shown in  FIG. 3 . It can be seen that the memory spring  201  according to this embodiment serves as a thermal actuator that drives the action of the valve core  40 , and the structure is simple. 
     In this embodiment, the memory spring  201  and the return spring  202  are both provided between the end cover  30  and the valve core  40 . Obviously, the arrangement manner is not limited to this. 
     Referring to  FIGS. 6 to 7 ,  FIG. 6  is a sectional view showing the structure of a thermostatic valve according to a second embodiment of the present application, with the second valve port A closed and the first valve port B opened; and  FIG. 7  is a schematic view of the thermostatic valve in  FIG. 6  after the valve core is moved to the right, with the first valve port B closed and the second valve port A opened. 
     This embodiment is basically the same as the first embodiment. The memory spring  201  is located between the end cover  30  and the valve core  40 . The memory spring  201  has one end in contact with another end of the valve core  40 , and another end in contact with the end cover  30 . A stepped hole is formed in the valve body  10 , and the large hole of the stepped hole is the valve cavity  10   a , and the first valve port B is formed at a junction of the small hole  10   c  and the large hole. The difference is that, in this embodiment, the return spring  202  in  FIG. 6  provides a resilience force instead of a pulling force, that is, the return spring  202  and the memory spring  201  can be respectively provided at two ends of the valve core  40 . One end of the return spring  202  is in contact with one end of the valve core  40 , and the other end of the return spring  202  abuts against the valve body  10  to provide the valve core  40  with a force in the opposite direction. 
     Specifically, the return spring  202  is provided in the small hole  10   c , and a step is provided in the small hole  10   c . The return spring  202  is pre-compressed between the valve core  40  and the step, to provide the resilience force for driving the valve core  40  away from the first valve port B, and the direction of the resilience force is opposite to the direction of the elastic force of the memory spring  201  applied on the valve core  40 . At this time, the right end, facing the return spring  202 , of the valve core  40  may be provided with a protrusion to be inserted into the return spring  202 , to assemble the return spring  202  and also play a role of positioning and guiding the valve core  40 . 
     Of course, the step may not be provided in the small hole  10   c , and the right end of the return spring  202  may directly abut against the inner wall of the linear passage  10   b , or a recessed hole is provided in the inner wall of the linear passage  10   b , and the right end of the return spring  202  directly abuts against the recessed hole. The return spring  202  can also be pre-compressed between the valve core  40  and the cavity wall of the right end portion of the valve cavity  10   a.    
     In addition, in the first and second embodiments, the right end of the valve core  40  is its sealing portion, which can block the first valve port B when the valve core  40  moves to the right; and the memory spring  201  serves as the sealing portion of the second valve port A. When the temperature of the medium is low, the memory spring  201  may be in a compressed and tight state and in correspondence to the position of the second valve port A, to block the second valve port A. When the memory spring  201  is heated up and expands, the memory spring  201  deforms and stretches, the diameter of the memory spring  201  decreases, and a gap appears between the second valve port A and the memory spring  201 , and a notch may also appear between several spring coils of the memory spring  201 , and the medium in the valve cavity  10   a  may flow through the gap and the notch to the second valve port A and then flow out. At this time, the second valve port A is opened. It can be seen that, with this arrangement, the memory spring  201  not only serves as a thermal actuator that drives the movement of the valve core  40 , but also serves as a sealing portion, thereby simplifying the structure of the valve core  40 . 
     Of course, the manner of blocking the second valve port A is not limited to that. Referring to  FIGS. 8 to 11 ,  FIG. 8  is a sectional view showing the structure of a thermostatic valve in an initial state according to a third embodiment of the present application, with a first valve port B having a preset opening degree and a second valve port A having a preset opening degree;  FIG. 9  is a schematic view of the thermostatic valve in  FIG. 8  after the temperature rises to a specified value and the memory spring  201  is deformed, with the first valve port B closed and the second valve port A opened;  FIG. 10  is a schematic view of the thermostatic valve in  FIG. 9  after the temperature drops below a specified value and the memory spring  201  loses characteristics, with the first valve port B opened and the second valve port A closed; and  FIG. 11  is a schematic view showing the structure of the valve core  40  in  FIG. 8 . 
     In this embodiment, the second valve port A is also provided in the side cavity wall of the valve cavity  10   a , and the first valve port B is provided in the end cavity wall of the valve cavity  10   a . In comparison, the valve core  40  in this embodiment is additionally provided with a sleeve portion  402 , and the memory spring  201  is provided in the sleeve portion  402  and located between the end cover  30  and the valve core  40 . At this time, the right end of the valve core  40  forms a first sealing portion for blocking the first valve port B, and the sleeve portion  402  on the valve core  40  forms a second sealing portion for blocking the second valve port A. Specifically, the outer wall of the sleeve portion  402  can slide along the side cavity wall of the valve cavity  10   a , to block or open the second valve port A. At this time, the memory spring  201  only serves as a thermal actuator that drives the valve core  40  to move according to temperature changes. 
     To facilitate the assembly of the memory spring  201 , a protruding platform is provided on the inner end surface of the end cover  30  facing the valve core  40 , and one end of the memory spring  201  is sleeved on the protruding platform. The valve core  40  includes a main body portion  401  extending in the axial direction and a sleeve portion  402  sleeved outside a part of the main body portion  401 . The left end of the main body portion  401  extends into the sleeve portion  402 . Another end of the memory spring  201  is sleeved on the left end of the main body portion  401 . The sleeve portion  402  and the main body portion  401  of the valve core  40  may be separately processed or integrally formed, as shown in  FIG. 11 . 
     In the third embodiment, same as the first and second embodiments, a stepped hole is also formed in the valve body  10 . The large hole of the stepped hole is the valve cavity  10   a , and the first valve port B is formed at the junction of the large hole of the stepped hole and the small hole  10   c . In addition, the right end of the main body portion  401  of the valve core  40  serves as a first sealing portion and is also connected to a guide rod  403 . The guide rod  403  and the main body portion  401  may be individually formed or integrally formed. The guide rod  403  can be inserted into the small hole  10   c  to guide the movement of the valve core  40 . The feature that the guide rod  403  is provided on the valve core  40  to be inserted into the small hole  10   c  for guiding is also applicable to other embodiments. As shown in  FIG. 11 , the end of the valve core  40  facing the first valve port B may be hollow, to reduce weight and save material. 
     In the second embodiment, as a sealing portion for sealing the first valve port B, the right end of the valve core  40  is provided with a protruding platform to be inserted into the return spring  202 . The return spring  202  is located in the small hole  10   c , and can also play a certain guiding role; however, in the third embodiment, the guide rod  403  is directly inserted into the small hole  10   c  for guiding, and the guiding effect is better. Since the sleeve portion  402  is provided, the step is not required to be processed on the hole wall of the small hole  10   c  to install the return spring  202 . The return spring  202  can be arrange between the sleeve portion  402  and the end cavity wall of the valve cavity  10   a , as shown in  FIG. 8 . 
     In addition, in the third embodiment, since the valve core  40  is provided with the sleeve portion  402 , the sleeve portion  402  is in sliding fit with the side cavity wall of the valve cavity  10   a , and an opening  402   b  is provided at the bottom of the sleeve portion  402  close to the first inlet  103 , as shown in  FIG. 11  (that is, below the bottom in  FIG. 8 ), so that the medium can flow into the inner cavity of the sleeve portion  402  and thus flows to the second valve port A. In order to facilitate the medium to come into contact with the memory spring  201  faster and more, a guiding inlet  402   a  penetrating the bottom is further provided at the bottom of the sleeve portion  402  away from the first inlet  103  (above the bottom in  FIG. 8 ) in  FIG. 8 , and as a flow guiding passage, the guiding inlet  402  is configured to communicate the valve cavity  10   a  with the inner cavity of the sleeve portion  402 . The number of the guiding inlet  402   a  may be one or more. 
     It should be noted that, in the third embodiment, an end protruding platform  401   a  is provided at the left end of the main body portion  401  of the valve core  40 . In the initial state, that is when leaving factory, one end of the memory spring  201  is surrounded around the end protruding platform  401   a , abuts against the stepped surface formed by the end protruding platform  401   a  and the main body portion  401 , which is the initial position of the end of the memory spring  201 . As shown in  FIG. 8 , the first valve port B is not fully opened and has a preset opening degree, the second valve port A also has an initial preset opening degree, so that the thermostatic valve has the characteristic of the second valve port A being always open in the initial state, thereby facilitating filling the lubricating oil into the transmission and at the same time filling the lubricating oil into the cooler in the initial state, to meet the requirement of the initial filling. That is, both valve ports are opened. 
     After that, when the temperature of the lubricating oil rises to a specified value, the memory spring  201  deforms and expands to a certain extent, thereby detaching from the end protruding platform  401   a  and surrounding the main body portion  401  with a greater outer diameter. The memory spring  201  is then switched to a normal working state, and always surrounds the main body portion  401 , as shown in  FIG. 9 , and is deformed to abut against the bottom position of the sleeve portion  402 . This position is the working position. At this time, the first valve port B is kept closed under the elastic force of the memory spring  201 . The initial position and working position of the end of the memory spring  201  described in the present application refer to the relative position of the end and the valve body  10  (the cavity wall of the valve cavity or the end cover  30  of the valve body  10 ) or the relative position of the end and the valve core  40 , and do not change as the valve core  40  moves. 
     When the temperature is lower than a specified value, the memory spring  201  loses its characteristic. Under the action of the return force of the return spring  202 , the valve core  40  moves and compresses the memory spring  201 . The distance between the bottom of the sleeve portion  402  and the end cover  30  is greater than the distance between the protruding platform of the main body portion  401  and the end cover  30 , thus when the memory spring  201  detaches from the protruding platform of the main body portion  401  and surrounds the main body portion  401 , the valve core  40  is closer to the end cover  30  under the action of the return spring  202 , and the sleeve portion  402  will block the second valve port A, eliminating the initial preset opening degree, as shown in  FIG. 10 . 
     It can be seen that a setting method is provided according to this embodiment, that is, a two-stage step (a stepped surface between the end protruding platform  401   a  and the main body portion  401  is a first stepped surface, and the bottom of the sleeve portion  402  is a second stepped surface) is provided on the valve core  40 , and the initial position and the working position are respectively formed by the first stepped surface and second stepped surface. When the memory spring  201  is at the initial position, the first valve port B has a preset opening degree, and the distance between the valve core  40  and the first valve port B when the memory spring  201  is at the initial position is smaller than the distance between the valve core  40  and the first valve port B when the memory spring  201  is at the working position and the temperature is below a specified value. 
     When the valve core  40  is at a certain position, the distance between the initial position and the end cover  40  is smaller than the distance between the working position and the end cover  40 . In this way, when the memory spring  201  is in any temperature environment (not affected by the specified value), the first valve port B maintains in a closed state, and the second valve port A has a preset opening degree (if the second valve port A is not provided, the medium can flow directly to the first outlet  104 ). After at the working position, the distance between the end cover  30  and the valve core  40  becomes longer, so that the return spring  202  can drive the valve core  40  to compress the memory spring  202  by more distance, thereby opening the first valve port B and closing the second valve port A. 
     It can be understood that the setting of the initial position and the working position is to adjust the distance between the valve core  40  and the end cover  30  or the valve core  40  and the valve body  10 , so that the distance between the two ends of the memory spring  201  can be compressed to different degrees at the two working positions, thereby achieving the opening and closing of the first valve port B. Therefore, the initial position and the working position can also be set at the valve core  40  or the valve body  10 , which can also be achieved by the two-stage step method, and both the valve core  40  and the valve body  10  can be set with the initial position and the working position, or both the valve core  40  and the end cover  30  can be set with the initial position and the working position, so that both ends of the memory spring  201  can abut against the initial position or the working position. 
     In the above embodiment, the first outlet  101 , the second inlet  102 , the second outlet  104 , and the first inlet  103  are all provided in the side wall of the valve body  10 , the first valve port B is provided in the end cavity wall of the valve cavity  10   a , and the second valve port A is provided in the side cavity wall of the valve cavity  10   a . The second outlet  104  and the second inlet  102  are opposite to each other, and a linear passage  10   b  (a linear passage  10   b  is also formed in the other embodiments described below) is formed between the second outlet  104  and the second inlet  102 . The first valve port B is in communication with the linear passage  10   b , which is specifically in communication with the linear passage  10   b  through the small hole  10   c  of the stepped hole in the above embodiment. In this way, the first inlet  103  and the second inlet  102  can share a passage to the second outlet  104 , thereby simplifying the structure and facilitating processing. Of course, other setting methods can also be adopted. 
     The inlets, outlets, and valve ports of the thermostatic valve can also be set by other ways. 
     Referring to  FIGS. 12 to 15 ,  FIG. 12  is a sectional view showing the structure of a thermostatic valve in an initial state according to a forth embodiment of the present application, with a first valve port B having a preset opening degree and a second valve port A having a preset opening degree;  FIG. 13  is a schematic view of the thermostatic valve in  FIG. 12  after the temperature rises to a specified value and the memory spring  201  is deformed, with the first valve port B closed and the second valve port A opened;  FIG. 14  is a schematic view of the thermostatic valve in  FIG. 13  after the temperature drops below a specified value and the memory spring  201  loses characteristics, with the first valve port B opened and the second valve port A closed; and  FIG. 15  is a schematic view showing the structure of the end cover  30  in  FIG. 12 . 
     In this embodiment, the end cover  30  actually not only covers the end port position of the valve body  10 , but also becomes a seat switching structure to function as a connector for communicating with the outside, specifically for communicating with the cooler in this embodiment. The switching seat is provided with a passage penetrating the inside and outside of the switching seat, and an outlet passage  10   d  is formed by the passage. The internal end port of the outlet passage  10   d  is the second valve port A, and the external end port is the first outlet  101 . At this time, the second valve port A and the first valve port B are distributed along the axial direction of the valve cavity  10   a . In this way, during the movement of the valve core  40 , one end of the valve core  40  may be a first sealing portion for blocking the first valve port B, and the other end is a second sealing portion for blocking the second valve port A. In this way, the operation is more convenient for the valve core  40  to block the first valve port B and the second valve port A, and the valve core  40  is easier to process. In this embodiment, in addition to the first outlet  101  of the thermostatic valve formed by the end cover  30  with the seat switching structure, the second outlet  104 , the second inlet  102 , and the first inlet  103  are also formed by connectors  50  externally connected to the valve body  10 . In the first to third embodiments, the outlets and inlets in communication with the outside are each directly formed as a connector-like structure on the valve body  10 , and both solutions are applicable to all embodiments of the present solution. 
     In addition, in the fourth embodiment, the setting of the initial preset opening degree is also performed. As can be understood with reference to  FIG. 15 , a two-stage step is provided at the inner end, toward the valve core  40 , of the switching seat, and the outer diameter of the first step is smaller than the outer diameter of the second step, forming a first step surface  301  and a second step surface  302  that both face the valve core  40 , the first step surface  301  is the initial position and the second step surface  302  is the working position. The distance between the valve core  40  and the initial position is smaller than the distance between the valve core  40  and the working position. In this way, in the initial state of leaving factory, the left end of the memory spring  201  is surrounded around the first step of the valve core  40  and abuts against the first step surface  301 . At this time, the first valve port B is closed and the second valve port A has the initial preset opening degree, as shown in  FIG. 12 , so that the thermostatic valve has the characteristic of the second valve port A being always open in the initial state, thereby facilitating filling the lubricating oil into the transmission in the initial state and at the same time filling the lubricating oil into the cooler, to meet the requirement of the initial filling. Of course, when the second valve port A is not provided, the memory spring  201  abuts against the initial position, the first valve port B is closed, and the lubricating oil can directly flow into the cooler through the first outlet  101 . 
     After that, when the temperature of the lubricating oil rises to a specified value, the memory spring  201  deforms and expands to a certain extent, thereby detaching from the first step and surrounding around the second step. After that, the memory spring  201  is switched to the normal working position and will be always surrounded around the second step, as shown in  FIG. 13 . The memory spring  201  is also deformed to abut against the second step surface  302 . At this time, the first valve port B is kept closed under the elastic force of the memory spring  201 . 
     When the temperature is lower than a specified value, the memory spring  201  loses its characteristic. Under the action of the return force of the return spring  202 , the valve core  40  moves and compresses the memory spring  201 . The distance between the second step surface  302  and the valve core  40  is greater than the distance between the first step surface  301  and the valve core  40 , thus when the memory spring  201  is detached from the first step and surrounded around the second step, the valve core  40  will be closer to the end cover  30  under the action of the return spring  202 , and the left end portion of the valve core  40  will block the second valve port A, eliminating the initial preset opening degree, and the first valve port B is now open. 
     In the fourth embodiment, the outer periphery of the end (the left end portion in  FIG. 12 , that is, the second sealing portion), facing the second valve port A, of the valve core  40  is tapered, that is, having a tapered surface that cooperates with the second valve port A, in order to better block the second valve port A and have a guiding effect. In order to facilitate abutting against the memory spring  201 , the left end portion of the valve core  40  is also provided with a peripheral protrusion as shown in  FIG. 12 , the right end of the memory spring  201  abuts against the peripheral protrusion. The end (the right end portion in  FIG. 12 , that is, the first sealing portion), facing the first valve port B, of the valve core  40  has a protruding platform and the protruding platform can be inserted into the return spring  202 . The return spring  202  is placed in the small hole  10   c.    
     The valve core  40  may also have other structures, as shown in  FIGS. 16 to 17 .  FIG. 16  is a sectional view showing the structure of a thermostatic valve in an initial state according to a fifth embodiment of the present application, with a first valve port B having a preset opening degree and a second valve port A having a preset opening degree; and  FIG. 17  is a schematic view of the thermostatic valve in  FIG. 16  after the temperature rises to a specified value and the memory spring  201  is deformed, with the first valve port B closed and the second valve port A opened. 
     This embodiment is basically same as the fourth embodiment, and the difference lies only in the structure of the valve core  40 . In this embodiment, the valve core  40  is a spherical body. When the spherical valve core  40  is used to block the first valve port B and the second valve port A, a better blocking effect can be realized. In other embodiments, the spherical valve core  40  may also be used, or at least the portion for blocking is processed into a spherical surface. 
     In the fifth embodiment, a two-stage step is also provided on the end cover  30  with the seat switching structure, so that the memory spring  201  has an initial shape and forms an initial preset opening degree, which facilitates to filling the cooling oil into the cooler. 
     Regarding the structure of the valve core  40 , reference can be further made to  FIG. 19 , which is a sectional view showing the structure of a thermostatic valve according to a sixth embodiment of the present application, with a first valve port B closed and a second valve port A opened; and  FIG. 20  is a schematic view showing the structure of the valve core  40  in  FIG. 19 . 
     This embodiment is the same as the fourth and fifth embodiments, except that the structure of the valve core  40  includes a spherical portion  404  and a sealing plate  405  connected to each other. The spherical portion  404  is used to block the second valve port A, and the sealing plate  405  is used to block the first valve port B. A recessed hole  405   a  is provided in the side of the sealing plate  405  facing the spherical portion  404 , so that the spherical portion  404  can be partially inserted into the recessed hole  405   a  to be fixed, thereby facilitating the fixation of the spherical portion  404  and the sealing plate  405 . A protrusion is provided on another side of the sealing plate  405 , to be inserted into the return spring  202 , which plays a role of positioning, guiding, and facilitating the installation of the return spring  202 . At this time, the spherical portion  404  is not required to satisfy the blocking of the two valve ports at the same time, and the memory spring  201  is located between the end cover  30  and the sealing plate  405 . 
     Referring to  FIG. 21  again,  FIG. 21  is a sectional view showing the structure of a thermostatic valve according to a seventh embodiment of the present application, with a first valve port B closed and a second valve port A opened. 
     Compared to the fourth to sixth embodiments, the difference in this embodiment lies only in the structure of the valve element  40 . The valve core  40  is cylindrical in this embodiment, and two end surfaces of the valve core  40  are used to seal the first valve port B and the second valve port A, respectively. A protrusion is also provided on the side of the valve core  40  facing the first valve port B, to be inserted into the return spring  202 , which has functions of positioning, guiding and facilitating the installation of the return spring  202 . 
     Referring to  FIGS. 22 to 25  continuously,  FIG. 22  is a sectional view showing the structure of a thermostatic valve according to an eighth embodiment of the present application, with a first valve port B opened and a second valve port A closed;  FIG. 23  is a schematic view of the thermostatic valve after the temperature rises and the memory spring  201  is deformed in  FIG. 22 , with the first valve port B closed and the second valve port A opened;  FIG. 24  is a schematic view of the end cover  30  and the valve core  40 , the return spring  202 , and the memory spring  201  in  FIG. 22  after installation; and  FIG. 25  is a schematic perspective view of  FIG. 24 . 
     Compared to the fourth to seventh embodiments, the second valve port A in this embodiment is also provided in the end cover  30  (the end cover is not embodied as the seat switching structure), but the first outlet  101  is still provided in the side wall of the valve body  10 . At this time, an outlet passage  10   d  communicating the first outlet  101  with the second valve port A is provided in the end cover  30  and the valve body  10 , and the outlet passage  10   d  is actually equivalent to an “L” shape, as shown in  FIG. 22 . The position of the second valve port A is similar to that of the fourth to seventh embodiments, which allows the valve core  40  to more conveniently move to realize blocking. 
     In addition, in this embodiment, the end cover  30  is provided with a hole, and the thermostatic valve is further provided with a valve stem  60 . One end of the valve stem  60  can be inserted into the hole along the axial direction to be fixed, and another end of the valve stem  60  extends out of the end cover  30 . The other end of the valve stem  60  extending out of the end cover  30  can be inserted into the valve core  40  and is in sliding fit with the valve core  40 . In this way, the valve core  40  can move along the valve stem  60  during the movement process, thereby having good positioning and guiding effects. 
     As shown in  FIGS. 24 and 25 , an annular passage is formed at the outer periphery of the end cover  30 , which facilitates the medium flowing to the first outlet  101 . In  FIG. 24 , the left end portion of the end cover  30  is used to block the left end port of the valve cavity  10   a , the second valve port A is formed at the right end portion, and a connector is provided between the left end portion and the right end portion. The valve stem  60  is inserted into the connector from the second valve port A and enters the left end portion. The left end portion, the right end portion, and the connector of the end cover  30  are integrally formed, so that the structure is reliable, achieving the reliable installation of the valve stem  60  and the memory spring  201 , and these members can be assembled first and then installed into the valve cover  10   a . Of course, the left end portion, the right end portion, and the connector of the end cover  30  may also be formed separately and then connected. 
     Obviously, the valve stem  60  is also applicable to other embodiments. For the embodiment where the first outlet  101  is provided in the end cover  30  with the seat switching structure, as shown in  FIG. 19 , the valve stem can be inserted into the passage of the end cover  30 , and the end portion of the valve stem can be fixed to the side wall of the passage by a connector. 
     It should be noted that, in the eighth embodiment, the valve stem  60  is fixed to the end cover  30 . It can be understood that the valve stem  60  can also be fixed to the valve core  40  and in sliding fit with the end cover  30 . In comparison, in case that the valve stem  60  is fixed to the end cover  30 , the valve core  40  can operate more smoothly and reliably. 
     Herein, the valve core  40  may be provided with a through hole to facilitate sliding along the valve stem  60 . In addition, a sealing piece  40 ′ is provided on the outer peripheral wall of the right end of the valve core  40 . The sealing piece  40 ′ serves as a first sealing portion for blocking the first valve port B. In order to install the return spring  202 , an annular groove is further provided in the outer peripheral wall of the right end of the valve core  40 . One end of the return spring  202  is inserted in the annular groove, another end of the return spring  202  abuts against the step of the small hole  10   c , of course, the another end of the return spring  202  can also abut against the inner wall of the linear passage  10   b  or the end cavity wall of the valve cavity  10   a , which has been described in the above embodiments, and will not be repeated here. 
     Regarding the sealing piece  40 ′, the sealing piece  40 ′ can also be integrally formed with the valve core  40 . As shown in  FIG. 26 ,  FIG. 26  is a sectional view showing the structure of a thermostatic valve according to a ninth embodiment of the present application, with a first valve port B closed and a second valve port A opened. When the sealing piece  40 ′ is integrally formed with the valve core  40 , it has a more reliable strength. The return spring  202  can directly abut against the sealing piece  40 ′. The return spring  202  shown in  FIG. 25  is pre-compressed on the step of the small hole  10   c  and the sealing piece  40 ′. The valve core  40  can be variously designed in each embodiment of the present application, and the structure of the valve core  40  in each embodiment can be used interchangeably. 
     It should be noted that, for each embodiment, when the first inlet  103  is provided in the side wall of the valve body  10 , in order to improve the reliability of the movement of the valve core  40 , the valve core  40  may be designed such that at least a portion of the valve core  40  is in sliding fit with the inner wall of the valve cavity  40 , which can prevent impact on the valve core  40  or the memory spring  201  when the fluid flows in. 
     Referring to  FIGS. 27 to 29 ,  FIG. 27  is a sectional view showing the structure of a thermostatic valve according to a tenth embodiment of the present application, with a first valve port B opened and a second valve port A closed;  FIG. 28  is a schematic view of the thermostatic valve in  FIG. 27  after the valve core is moved to the right, with the second valve port A opened and the first valve port B closed; and  FIG. 29  is a schematic view of the valve core  40  in  FIG. 27 . 
     In this embodiment, the valve core  40  is movable axially along the valve cavity  10   a , and a portion of the valve core  40  is in sliding fit with the inner wall of the valve cavity  10   a . The first valve port B is located at the end cavity wall of the valve cavity  10   a , that is, the axial cavity wall, and the second valve port A is located at the side cavity wall of the valve cavity  10   a , that is, the radial cavity wall. In this solution, the first inlet  103  and the second valve port A are opposite to each other. Specifically, the inlet passage  10   e  communicating the first inlet  103  with the valve cavity  10   a  is opposite to the second valve port A and the outlet passage  10   d . In this way, the passage between the first inlet  103  and the first outlet  101  is the linear passage. As shown in  FIG. 28 , when the second valve port A is opened, the medium can flow out through the linear passage, and the response is faster. 
     The structure of the valve core  40  in this embodiment is similar to that in the third embodiment. The valve core  40  includes a sleeve portion  402  acting as a second sealing portion for blocking the second valve port A. The memory spring  201  is provided in the sleeve portion  402  and is located between the valve core  40  and the end cover  30 . Of course, it is also feasible to block the second valve port A by using the valve core  40  with other structures or the memory spring  201 . 
     In addition, in the tenth embodiment, a notch  402   c  is provided at an edge of the open end of the sleeve portion  402 , to function as a flow guiding passage for guiding a medium into the sleeve portion  402 . As shown in  FIG. 27 , when the sleeve portion  402  is used to block the second valve port A, the medium can enter the sleeve portion  402  through the position of the notch  402   c , so that the memory spring  201  can be in contact with the heated medium and deform in time. It can be understood that the flow guiding passage is not limited to the notch  402   c  shown in the figure, for example, it may also be provided in the side wall or the bottom of the sleeve portion  402 . 
     It should be noted that the outlet passage  10   d  and the inlet passage  10   e  in this embodiment are oppositely arranged. When the sleeve portion  402  is in sliding fit with the inner wall of the valve cavity  10   a , in order to avoid blocking the passage between the medium and the first valve port B, in  FIG. 27 , a part of the outer wall of the sleeve portion  402  corresponding to the second valve port A is in sliding fit with the inner wall of the valve cavity  10   a , and a gap is provided between the part, corresponding to the inlet passage  10   e  and the first inlet  103 , of the outer wall of the sleeve portion  402  and the inner wall of the valve cavity  10   a , which can ensure that the medium can flow to the first valve port B. That is, the second sealing portion is only required to seal the second valve port A, and a gap is required to be provided between the portion, facing the inlet passage  10   e , of the sleeve portion  402  and the inner wall of the valve cavity  10   a . As shown in  FIG. 27 , the central axis of the valve cavity  10   a  is offset from the central axis of the valve core  40 , and the portion, opposite to the inlet passage  10   e , of the valve cavity  10   a  is concave. Of course, it can be understood that the valve cavity  10   a  may not be concave, and the valve core  40  may be provided as an eccentric structure relative to the axis. This manner of a portion of the valve core  40  in sliding fit with the inner wall of the valve cavity  10   a  not only satisfies stability and impact resistance, but also facilitates fluid flow. 
     In addition, in this embodiment, a two-stage stepped hole is formed in the valve body  10  of the thermostatic valve, the largest hole is the valve cavity  10   a , and a first valve port B is formed at a junction between the middle hole and the largest hole. In this way, the stroke of the valve core  40  moving to block the first valve port B can be shortened. Of course, it is also applicable to provide a stepped hole including a large hole and a small hole as in the above embodiment. 
     The second inlet  102  and the second outlet  104  in this embodiment are also opposite to each other, and a linear passage  10   b  is formed between the second inlet  102  and the second outlet  104 , and the return spring  202  penetrates the smallest hole and is compressed between the valve core  40  and the inner wall of the linear passage  10   b . A groove allowing the end portion of the return spring  202  to be inserted can be provided in the inner wall of the linear passage  10   b . Obviously, the end portion of the return spring  202  may also be compressed on the end wall of the valve cavity  10   a , or a step may be provided at the smallest hole, and the end portion of the return spring  202  can be compressed on the step or the valve core  40 . 
     It should be noted that, in the above embodiment, the formed valve cavity  10   a  is a cavity with an end port at one end, an end cover  30  is provided at the end port, and the memory spring  201  is provided between the end cover  30  and the valve core  40 . This method is convenient for machining the valve body  10  to form the valve cavity  10   a , but it can be understood that the structure of the valve cavity  10   a  is not limited thereto. For example, when using a casting process, two ends of the valve cavity  10   a  may not have end ports, and no end covers are provided. Then, the memory spring  201  and the return spring  202  (in the first embodiment) may be provided between the cavity wall of the valve cavity  10   a  and the valve core  40 . 
     It can be seen from the embodiment with the preset opening degree that the purpose of setting the two-stage step is to use the characteristic of the memory spring  201 , to allow the memory spring  201  to switch from the initial position to the working position after being heated, expanded and deformed, and to be kept at the working position. Therefore, the solutions for realizing the purpose is not limited to providing the two-stage step. For example, an annular groove is provided at the end portion of the valve core  40 , and an end portion of the memory spring  201  is provided in the annular groove, and after the temperature rises, this end portion of the memory spring  201  is detached from the annular groove and abuts against other position as the working position, which can also achieve the purpose of setting the initial preset opening degree. 
     In the above embodiment, the control element for controlling the movement of the valve core  40  of the thermostatic valve is the memory spring  201 . Compared with the solution that the spring is surrounded around the thermal actuator, the response time of the memory spring  201  is faster, and the second valve port A can be opened in time to switch the medium to another flow path. When being applied to the cooler and the transmission, it can improve the performance of the transmission and prevent damages to the transmission. 
     Further, in this case, a thermal actuator is not required to be additionally provided in the thermostatic valve, the structure is simple and the installation is convenient, which allows the whole thermostatic valve lighter in weight and smaller in volume. 
     It should be noted that in the above embodiments, as an example, the valve body  10  is provided with the first valve port B and the second valve port A. It can be understood that the second valve port A may not be provided, that is the second valve port A that can be opened and closed is not provided, but the passage between the first outlet  101  and the valve cavity  10   a  is through. Taking the application to the transmission and the cooler as an example, when the first valve port B is closed, the medium (such as lubricating oil) can directly flow to the cooler, when the first valve port B is opened, even if there is no second valve port A and only the outlet passage in communication with the first outlet  101  is provided, because the cooler is in communication with the first outlet  101 , the flow resistance of the flow path through the first outlet  101  will be greater than the flow resistance of the flow path directly flowing to the second outlet  104  through the first valve port B. Therefore, the medium will mostly flow through the first valve port B to the second outlet  104 . Of course, by providing the second valve port A and switching the opening and closing states of the second valve port A and the first valve port B, it can more clearly distribute the flow paths of the medium under different requirements and reduce the system internal leakage. 
     In addition, when the second valve port A is not provided, in the above embodiment with the initial position and working position, it can be designed in a way that when the memory spring  201  is at the initial position, the first valve port B is closed, so that the lubricating oil can be directly flows into the cooler from the first outlet  101  to fill the lubricating oil in the initial state. At the same time, a second inlet  102  should be provided, and the first valve port B will also be in communication with the second inlet  102 , so that the lubricating oil flowing in from the second inlet  102  can also fill the passage between the first valve port B and the transmission, to complete the oil filling process of the whole system. 
     When the second valve port A is provided, the first valve port B may have a preset opening degree as described in the above embodiment, and may also be closed. When the first valve port B is closed, the valve body  10  of the thermostatic valve is also preferably provided with the second inlet  102  in communication with the second outlet  104 , so that the lubricating oil flowing in from the second inlet  102  can also fill the passage between the first valve port B and the transmission. Of course, when the first valve port B has a preset opening degree at the initial position, the passage between the first valve port B and the transmission can be filled. The solution is not limited to providing the second inlet  102  in the valve body  10 , and the outlet of the cooler can also be connected to the transmission through other passages. 
     Regardless of whether or not the second valve port A is provided, in order to facilitate filling the cooler in the initial state, it can be set as follows: a distance between the valve core  40  and the first valve port B when the memory spring  201  is at the initial position is smaller than the distance between the valve core  40  and the first valve port B when the memory spring is at the working position and the temperature is below a specified value. In this way, when the memory spring  201  is below the temperature with the specified value, the length of the memory spring  201  changes, so that the first valve port B and/or the second valve port A can be adjusted to have different opening degrees at the initial position and working position. 
     The above embodiments are only preferred embodiments of the present application. It should be noted that, for the person skilled in the art, a few of modifications and improvements may be made to the present application without departing from the principle of the present application, and these modifications and improvements are also deemed to fall into the scope of protection of the present application.