Thermostat device

Abstract

Provided is a thermostat device which easily allows dimensional tolerances of components, which is easy to assemble, install, and replace, and in which a thermostat and a differential pressure valve are integrated. A thermostat device 1 includes a thermostat 10 for opening / closing a main passage, a differential pressure valve 20 for opening / closing a bypass passage, and a connection unit 26 that connects the thermostat 10 and the differential pressure valve 20. The connection unit 26 includes a holder 27 fixed to an inner periphery of the second valve seat member 21 of the differential pressure valve 20, a flange 27b protruding outward from the holder 27, an engagement part 19a provided in the frame 19 of the thermostat 10 and hooked by the flange 27b, and a holder-biasing member 18 that biases the holder 27 in a direction in which the hooking of the flange 27b to the engagement part 19a is maintained.

Description

Thermostat device

[0001] The present invention relates to a thermostat device, and more particularly to a thermostat device in which a thermostat and a differential pressure valve are connected together.

[0002] The engine coolant circuit disclosed in Patent Document 1 includes a main passage that circulates engine coolant via a radiator, a bypass passage that bypasses the radiator and is connected in parallel to the main passage, a thermostat installed at the branch point of these two passages, and a car heater passage that bypasses the radiator and is connected in parallel to the main passage. The thermostat includes a main passage opening / closing valve and a bypass passage opening / closing valve that selectively open and close the main passage and the bypass passage by detecting the temperature of the coolant.

[0003] A flow control valve is also integrally connected to the thermostat. When the bypass passage opening / closing valve is in a position to open the bypass passage, the opening degree of the flow control valve is determined by the balance between the urging force of a spring that urges the valve port facing the bypass passage in a direction to close the valve port from the bypass passage side and the coolant pressure.

[0004] To integrate the flow control valve with the thermostat, a rod is fixed to the bottom wall of the wax-filled pellet body of the thermostat by welding or adhesive, and the rod is fitted into the center hole of the flow control valve.The flow control valve is then guided by the rod and allowed to move up and down within a case fixed to the bottom of the cylindrical case of the thermostat by welding, etc. However, this structure has the problem of being difficult to tolerate the dimensional tolerances of each part.

[0005] Japanese Utility Model Publication No. 62-15470

[0006] One object of the present invention is to provide a thermostat device that integrates a thermostat and a differential pressure valve, which can easily tolerate dimensional tolerances of parts, is easy to assemble, and can be easily attached to and replaced in a main passage and a bypass passage.

[0007] One aspect of the present invention is a thermostat device to be mounted at a branch point between a main passage and a bypass passage, the thermostat comprising: a thermostat for opening and closing the main passage; a differential pressure valve for opening and closing the bypass passage; and a connecting unit for connecting the thermostat and the differential pressure valve. The thermostat comprises: a first valve seat member having a first opening for communicating with the main passage; a first valve body that opens and closes the first opening by seating on and removing from the first valve seat member; a valve stem to which the first valve body is fixed; a temperature sensing unit that is fixed to a base end of the valve stem and is filled with a material that expands or contracts in response to temperature; and a thermoelement that protrudes from the tip of the valve stem and moves back and forth in response to the expansion or contraction of the material; and a piston that biases the first valve body in a closing direction. the differential pressure valve comprises a second valve seat member having a second opening formed therein for communication with the bypass passage, a second valve body that opens and closes the second opening by being seated on and released from the second valve seat member, a second biasing member that biases the second valve body in a closing direction, and a support member that is fixed to the second valve seat member and supports the second biasing member; and the connecting unit comprises a holder that has a communication hole on its side and has the second valve seat member fixed to its inner periphery, a flange that protrudes outward from the holder, an engaging portion that is provided on the frame and on which the flange is hooked, and a holder biasing member that biases the holder in a direction that maintains the flange hooked on the engaging portion.

[0008] In the thermostat device, the holder biasing member may be the first biasing member that presses the flange protruding from the holder in a direction that maintains the flange hooked onto the engaging portion.

[0009] In the thermostat device, the holder biasing member may be a third biasing member that is different from the first biasing member and the second biasing member and is sandwiched and compressed between the frame and the holder.

[0010] The thermostat device may further include an auxiliary passage that always communicates from the main passage to the bypass passage when the thermostat device is installed.

[0011] The auxiliary passage may be a gap between the inlet of the bypass passage and the holder inserted into the inlet.

[0012] The auxiliary passage may be a gap in the second opening that is not closed by the second valve body when the second valve body is seated on the second valve seat member.

[0013] The present invention is not limited to the above objects or embodiments. A more complete understanding of the present invention and many of the advantages thereof will be readily apparent from the following detailed description taken in conjunction with the accompanying drawings.

[0014] 7A is a cross-sectional view of a thermostat device according to a first embodiment of the present invention, mounted at the branch point between a main passage and a bypass passage; FIG. 7B is a cross-sectional view of the differential pressure valve according to the first embodiment when the valve is open; FIG. 7A is a diagram showing a method for assembling the differential pressure valve according to the first embodiment; FIG. 7B is a diagram showing a method for assembling the thermostat device according to the first embodiment; FIG. 7C is a perspective view of the assembled thermostat device according to the first embodiment; FIG. 7B is a cross-sectional view of a thermostat device according to a second embodiment of the present invention, mounted at the branch point between a main passage and a bypass passage; FIG. 7C is a cross-sectional view of the differential pressure valve according to the second embodiment when the valve is open; FIG. 7A is a diagram showing a method for assembling the differential pressure valve according to the second embodiment; FIG. 7B is a diagram showing a method for assembling the thermostat device according to the second embodiment; FIG. 7C is a diagram showing a method for assembling the thermostat device according to the second embodiment; FIG. 7D is a perspective view of the assembled thermostat device according to the second embodiment; FIG. 7A is a perspective view of a thermostat device according to another embodiment of the present invention; FIG. 7B is a cross-sectional view of the thermostat device according to (a) taken along line 7B-7B.

[0015] [First Embodiment] A thermostat device 1 according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 3. The terms "upper," "lower," "left," and "right" used in the descriptions of the various embodiments of the present invention refer, for convenience, to the terms "upper," "lower," "left," and "right," respectively, in the drawings referred to in the descriptions. The thermostat device 1 is mounted in a passage through which a coolant flows to cool an engine, such as an automobile. In FIG. 1, the thermostat device 1 is mounted at a branch point on the engine outlet side between a main passage 2, 2a that circulates the coolant between the engine and a radiator, and a bypass passage 3 that bypasses the radiator and is connected in parallel to the main passage 2a. The outline arrows in FIG. 1 indicate the direction of coolant flow in the passage 2, a partial passage 2a of the main passage 2 extending from the branch point toward the radiator, and the bypass passage 3.

[0016] The thermostat device 1 includes a thermostat 10 for opening and closing the main passages 2, 2a, a differential pressure valve 20 for opening and closing the bypass passage 3, and a connecting unit 26 for connecting the thermostat 10 and the differential pressure valve 20.

[0017] The thermostat 10 will now be described. The thermostat 10 comprises a first valve seat member 11 having a first opening 11a for communication with the main passages 2, 2a, a first valve element 12 that opens and closes the first opening 11a by seating on and off the first valve seat member 11, a valve stem 13 to which the first valve element 12 is fixed, a thermoelement 16 having a temperature sensing part 14 fixed to the base end of the valve stem 13 and filled with a material that expands or contracts in response to temperature, and a piston 15 protruding from the tip of the valve stem 13 and moving back and forth in response to the expansion or contraction of the material, a first biasing member 18 that biases the first valve element 12 in a closing direction, and a frame 19 fixed to the first valve seat member 11 and supporting the first biasing member 18.

[0018] The first valve seat member 11 has a cylindrical portion 11b having the first opening 11a on its inner periphery, and an annular portion 11c protruding outward from the cylindrical portion 11b. When the first valve body 12 is seated on the annular portion 11c of the first valve seat member 11, the first opening 11a is closed, and the coolant does not flow from the main passage 2 to the partial passage 2a. When the first valve body 12 is separated from the annular portion 11c, the first opening 11a is opened, and the coolant flows from the main passage 2 to the partial passage 2a of the main passage 2 through the first opening 11a.

[0019] The first valve body 12 is passed through and fixed to the valve stem 13. The material sealed inside the temperature sensing part 14 is made of wax or the like, which senses the temperature of the cooling water around the temperature sensing part 14 and expands when the temperature rises and contracts when the temperature drops. The piston 15 passes through the valve stem 13 in the axial direction. As the piston 15 advances and retreats in response to the expansion and contraction of the material, the length of the part of the piston 15 protruding from the tip of the valve stem 13 expands and contracts.

[0020] The piston receiver 17 is located on the central axis of the piston 15 and is supported by a pair of arms 11d extending from opposing positions on the cylindrical portion 11b of the first valve seat member 11 toward the piston receiver 17. The piston receiver 17 abuts against and presses down on the tip of the piston 15. When the portion of the piston 15 protruding from the tip of the valve stem 13 becomes longer, the first valve body 12, the valve stem 13, and the temperature sensor 14 move together in a direction away from the first valve seat member 11. On the other hand, when the protruding portion of the piston 15 becomes shorter, the first valve body 12, the valve stem 13, and the temperature sensor 14 move together in a direction toward the first valve seat member 11.

[0021] The first biasing member 18 is, for example, a coil spring. One end of the first biasing member 18 presses the first valve body 12 from the branch point side in a direction to close the first opening 11 a. The temperature sensing portion 14 of the thermo-element 16 is inserted into the first biasing member 18.

[0022] The frame 19 includes an annular bottom 19a that supports the other end of the first biasing member 18, a bottom opening 19b that opens to the inside of the bottom 19a, and a pair of pillars 19c that extend upward from opposing positions on the bottom 19a and are fixed to the annular portion 11c of the first valve seat member 11. The inside and outside of the frame 19 are connected by an opening formed between the pair of pillars 19c and the bottom opening 19b.

[0023] The differential pressure valve 20 will now be described. The differential pressure valve 20 includes a second valve seat member 21 having a second opening 21a for communicating with the bypass passage 3, a second valve body 22 that opens and closes the second opening 21a by being seated on and separated from the second valve seat member 21, a second biasing member 23 that biases the second valve body 22 in the closing direction, and a support member 24 that is fixed to the second valve seat member 21 and supports the second biasing member 23.

[0024] The second valve seat member 21 has a connection hole 21b formed in its center, and the second opening 21a formed around the connection hole 21b. The second valve body 22 is a poppet valve having a central hole 22a and recessed from its outer periphery toward the central hole 21a. The second biasing member 23 is a coil spring, one end of which abuts against the second valve body 22 and presses the second valve body 22 in the closing direction from the bypass passage 3 side.

[0025] When the second valve body 22 is seated on the second valve seat 21, the second opening 21 a is closed, and the coolant does not flow through the second opening 21 a into the bypass passage 3. When the second valve body 22 is separated from the second valve seat 21, the second opening 21 a is opened, and the coolant flows through the second opening 21 a into the bypass passage 3.

[0026] The support member 24 has, stacked in ascending order of outer diameter, a coupling protrusion 24a that passes through the coupling hole 21b, a second valve element guide 24b that is inserted into the central hole 22a of the valve element 22, a second biasing member guide 24c that is inserted into the second biasing member 23, and a second biasing member receiver 24d that supports the other end of the second biasing member 23. The push nut 25 has a press-fit hole 25a in its center. The second valve seat member 21 and the support member 24 are fixed together by press-fitting the coupling protrusion 24a into the press-fit hole 25a.

[0027] The connecting unit 26 will now be described. The connecting unit 26 includes a holder 27 having the second valve seat member 21 fixed to the inner periphery of a cylindrical side wall 27a, a flange 27b protruding outward from the holder 27, a bottom 19a of the frame 19 that is provided on the frame 19 and constitutes an engagement portion on which the flange 27b is hooked, and the first biasing member 18 that constitutes a holder biasing member that biases the holder 27 in a direction that keeps the flange 27b hooked on the bottom 19a that is the engagement portion.

[0028] A cylindrical side wall 27a of the holder 27 is provided with a plurality of communication holes 27c that communicate between the inside and outside of the holder 27. The second valve seat member 21 is fixed integrally to the inner periphery of the side wall 27a of the holder 27 near the lower end. The upper end of the holder 27 is open, allowing the temperature sensor 14 to be freely inserted into the holder 27. When the temperature sensor 14 is inserted into the holder 27, a gap is formed between the two to serve as a passageway for the coolant to flow.

[0029] The outer diameter of the side wall 27a of the holder 27 is approximately the same as the inner diameter of the bottom opening 19b of the frame 19. The outer diameter of the annular flange 27b protruding outward near the upper end of the holder 27 is larger than the inner diameter of the bottom opening 19b of the frame 19. When the holder 27 is inserted into the bottom opening 19b, the flange 27b is caught on the bottom 19a of the frame 19, i.e., the engaging portion, and is thereby supported by the frame 19.

[0030] The first biasing member 18 constituting the holder biasing member presses the flange 27b protruding from the holder 27, biasing it in a direction that keeps the flange 27b hooked on the bottom portion 19a constituting the engagement portion. The first biasing member 18 is sandwiched and compressed and held between the flange 27b supported on the bottom portion 19a of the frame 19 and the first valve body 12.

[0031] Next, a method of assembling the thermostat device 1 will be described with reference to Fig. 3. As shown in Fig. 3(a), the support member 24 is inserted through the second biasing member 23, the central hole 22a of the second valve body 22, and the connecting hole 21b of the first valve seat member 21, and then the connecting protrusion 24a is press-fitted into the press-fit hole 25a of the push nut 25. In this way, the differential pressure valve 20 is integrally formed.

[0032] As shown in Figures 3(b) and 3(c), the holder 27 of the differential pressure valve 20 is inserted into the bottom opening 19b of the frame 19, and the flange 27b is hooked onto the engaging portion, which is the bottom 19a of the frame 19. While the first biasing member 18 is sandwiched and pressed between the flange 27b and the first valve body 12, the protrusion 19d provided at the tip of the column portion 19c of the frame 19 is inserted into the hole 11e provided in the annular portion 11c of the first valve seat member 11 and crimped. Furthermore, the gasket 28 made of an elastic material such as rubber is fitted onto the outer periphery of the annular portion 11c of the first valve seat member 11. In this manner, the thermostat device 1, in which the thermostat 10 and the differential pressure valve 20 are integrated, is assembled.

[0033] Next, the operation of the thermostat device 1 will be described. In Figure 1, the thermostat device 1 is attached to the branch point of the main passage 2, through which coolant flows from the engine coolant outlet toward the radiator, and the bypass passage 3. The thermostat 10 is installed near the entrance of a partial passage 2a of the main passage 2 that runs from the branch point toward the radiator. The gasket 28 seals the partial passage 2a from the thermostat 10.

[0034] The coolant in the main passage 2 flows into the frame 19 from the opening formed between the pair of pillars 19c, or flows into the holder 27 through the communication hole 27c, and further flows through the gap between the holder 27 and the temperature sensing part 14. Therefore, the entire temperature sensing part 14 of the thermo-element 16 can sense the temperature of the coolant.

[0035] When the differential pressure valve 20 is arranged so that the holder 27 is inserted into the inlet of the bypass passage 3, a gap exists between the inlet of the bypass passage 3 and the holder 27. The gap forms an auxiliary passage 29 that constantly connects the main passage 2 and the bypass passage 3.

[0036] By providing the auxiliary passage 29, even when the second valve body closes the second opening, the coolant can always flow from the main passage 2 through the auxiliary passage 29 to the bypass passage 3. The temperature sensing portion 14 of the thermo-element 16 can always sense the temperature of the coolant.

[0037] Furthermore, since it is assumed that a gap will be formed between the inlet of the bypass passage 3 and the holder 27, the holder 27 is likely to be allowed a dimensional tolerance in the outer diameter, making design and installation easier.

[0038] When the coolant temperature sensed by the temperature sensing portion 14 is lower than a predetermined temperature, the wax in the temperature sensing portion 14 contracts, and the length of the portion of the piston 15 that protrudes from the valve stem portion 13 is minimized. In this case, the first valve body 12 is pressed by the first biasing member 18 to seat on the first valve seat member 11, the first opening 11a is closed, and the coolant does not flow from the main passage 2 to the partial passage 2a leading to the radiator.

[0039] In this case, when the pressure of the coolant is extremely small, the second valve body 22 of the differential pressure valve 20 is seated on the second valve seat member 21 by the second biasing member 23, thereby closing the second opening 21 a. However, the coolant in the main passage 2 flows into the bypass passage 3 through the auxiliary passage 29, which is the gap between the inlet of the bypass passage 3 and the holder 27.

[0040] 2, as the pressure of the coolant increases, the second valve body 22 is pressed down against the pressing force of the second biasing member 23, and the second opening 21a opens. The valve opening of the differential pressure valve 20 is controlled to a position where the pressure of the coolant and the pressing force of the second biasing member 23 are balanced. The coolant flows through the auxiliary passage 29 and the second opening 21a to the bypass passage 3, and the flow rate of the coolant flowing to the bypass passage 3 increases.

[0041] When the coolant temperature reaches a predetermined temperature or higher, the wax in the temperature sensing portion 14 senses the temperature and expands, increasing the length of the portion of the piston 15 that protrudes from the valve stem 13. However, the tip of the piston 15 is pressed by the piston receiver 17, causing the first valve body 12, the valve stem 13, and the temperature sensing portion 14 to descend together. As a result, the first valve body 12 descends against the pressing force of the first biasing member 18, opening the first opening 11a. As a result, the coolant that has flowed into the frame 19 flows from the first opening 11a, through the opening between the pair of arms 11d, and into the partial passage 2a of the main passage 2 that leads to the radiator. When the opening amount of the first valve body 12 increases, most of the cooling water flows into the partial passage 2 a, and the cooling water pressure to the differential pressure valve 20 decreases, so that the second valve body 22 seats on the second valve seat member 21 and closes the second opening 21 a. Some of the cooling water in the main passage 2 flows through the auxiliary passage 29 to the bypass passage 3.

[0042] According to the thermostat device 1, the flange 27b protruding outward from the holder 27, to which the second valve seat member 21 of the differential pressure valve 10 is fixed on the inner periphery, is caught on the engaging portion, which is the bottom 19a of the frame 19 of the thermostat 10. Furthermore, the holder biasing member, which is the first biasing member 18, presses the flange 27b in a direction that maintains the flange 27b being caught on the bottom 19a, which is the engaging portion. In this way, it is possible to obtain the thermostat device 1 in which the thermostat 10 and the differential pressure valve 20 are integrally connected, which easily tolerates dimensional tolerances of parts, is easy to assemble, and is easy to install in and replace in the main passage and the bypass passage.

[0043] Furthermore, by modifying an existing thermostat to have a frame having the shape and structure of the frame 19 and further adopting the differential pressure valve 20 and the connecting unit 26, it is possible to easily modify the existing thermostat into a thermostat device with an integrated differential pressure valve.

[0044] The thermostat device 1 is easily miniaturized because the holder biasing member is also used by the first biasing member 18, which presses the flange 27b protruding from the holder 27 in a direction that keeps it hooked onto the engaging portion, which is the bottom 19a of the frame 19.

[0045] [Second Embodiment] Next, a thermostat device 4 according to a second embodiment of the present invention will be described with reference to Figures 4 to 6. In Figure 4, the thermostat device 4 according to the second embodiment is mounted at the branch point on the engine outlet side between the main passages 5, 5a that circulate the coolant between the engine and the radiator and the bypass passage 6 that bypasses the radiator and is connected in parallel to the main passage 5. The outline arrows in Figure 4 indicate the direction in which the coolant flows in the main passage 5, the partial passage 5a of the main passage 5 that runs from the branch point toward the radiator, and the bypass passage 6.

[0046] The thermostat device 4 includes a thermostat 30 for opening and closing the main passages 5, 5a, a differential pressure valve 40 for opening and closing the bypass passage 6, and a connecting unit 45 for connecting the thermostat 30 and the differential pressure valve 40.

[0047] The thermostat 30 will now be described. The thermostat 30 comprises a first valve seat member 31 having a first opening 31a for communication with the main passages 5, 5a, a first valve element 32 that opens and closes the first opening 31a by seating on and off the first valve seat member 31, a valve stem 33 to which the first valve element 32 is fixed, a temperature sensing part 34 that is fixed to the base end of the valve stem 33 and is filled with a material that expands or contracts in response to temperature, and a thermoelement 36 that protrudes from the tip of the valve stem 33 and moves back and forth in response to the expansion or contraction of the material, a first biasing member 38 that biases the first valve element 32 in a closing direction, and a frame 39 that is fixed to the first valve seat member 31 and supports the first biasing member 38.

[0048] The first valve seat member 31 has a cylindrical portion 31b having the first opening 31a on its inner periphery, and an annular portion 31c protruding outward from the cylindrical portion 31b. When the first valve body 32 is seated on the annular portion 31c of the first valve seat member 31, the first opening 31a is closed, and the coolant does not flow from the main passage 5 to the partial passage 5a. When the first valve body 32 is separated from the annular portion 31c, the first opening 31a is opened, and the coolant flows from the main passage 5 to the partial passage 5a of the main passage 5 through the first opening 31a.

[0049] The first valve body 32 is passed through and fixed to the valve stem 33. The material sealed inside the temperature sensing portion 34 is wax or the like that senses the temperature of the cooling water around the temperature sensing portion 34 and expands when the temperature rises and contracts when the temperature drops. The piston 35 passes through the valve stem 33 in the axial direction. As the piston 35 moves back and forth in response to the expansion and contraction of the material, the length of the portion of the piston 35 protruding from the tip of the valve stem 33 increases or decreases.

[0050] The piston receiver 37 is located on the central axis of the piston 35 and is supported by a pair of arms 31d extending from opposing positions on the cylindrical portion 31b of the first valve seat member 31 toward the piston receiver 37. The piston receiver 37 abuts against and presses the tip of the piston 35. When the portion of the piston 35 protruding from the tip of the valve stem 33 becomes longer, the first valve body 32, the valve stem 33, and the temperature sensor 34 move together in a direction away from the first valve seat member 31. On the other hand, when the protruding portion of the piston 35 becomes shorter, the first valve body 32, the valve stem 33, and the temperature sensor 34 move together in a direction toward the first valve seat member 31.

[0051] The first biasing member 38 is, for example, a coil spring. One end of the first biasing member 38 presses the first valve body 32 from the branch point side in a direction to close the first opening 31 a. The temperature sensing portion 34 of the thermo-element 36 is inserted into the first biasing member 38.

[0052] The frame 39 includes an annular bottom 39a that supports the other end of the first biasing member 38, a bottom opening 39b that opens to the inside of the bottom 39a, and a pair of pillars 39c that extend upward from opposing positions on the bottom 39a and are fixed to the annular portion 31c of the first valve seat member 31. The inside and outside of the frame 39 are connected by an opening formed between the pair of pillars 39c and the bottom opening 39b.

[0053] The differential pressure valve 40 will now be described. The differential pressure valve 40 includes a second valve seat member 41 having a second opening 41a for communicating with the bypass passage 6, a second valve body 42 that opens and closes the second opening 41a by being seated on and separated from the second valve seat member 41, a second biasing member 43 that biases the second valve body 42 in the closing direction, and a support member 44 that is fixed to the second valve seat member 41 and supports the second biasing member 43.

[0054] The second valve seat member 41 has a connection hole 41b formed in its center, and the second opening 41a formed around the connection hole 41b. The second valve body 42 is a poppet valve with a central hole 42a and recessed from its outer periphery toward the central hole 41a. The second biasing member 43 is a coil spring, one end of which abuts against the second valve body 42 and presses the second valve body 42 in the closing direction from the bypass passage 3 side.

[0055] When the second valve body 42 is seated on the second valve seat 41, a gap 41c that is not closed by the second valve body is present in the second opening 41a, and the coolant flows through the gap 41c in the second opening 41a to the bypass passage 3. The gap 41c forms an auxiliary passage that constantly communicates from the main passage 5 to the bypass passage 6. As shown in FIG. 5 , when the second valve body 42 is separated from the second valve seat 41, the second opening 41a is entirely opened. At this time, the coolant flows through the entire second opening 41a to the bypass passage 3.

[0056] Even when the second valve body 42 is seated on the second valve seat 41, the gap 41c that constitutes the auxiliary passage exists, so the coolant always communicates from the main passage 5 to the bypass passage 6, and the temperature sensor 34 can always sense the temperature of the coolant.

[0057] The support member 44 has a connecting protrusion 44a that passes through the connecting hole 41b, a second valve body guide 44b that is inserted into the central hole 42a of the valve body 42, a second biasing member guide 44c that is inserted into the second biasing member 43, and a second biasing member holder 44d that supports the other end of the second biasing member 43, stacked in order of decreasing outer diameter.

[0058] The connecting unit 45 will now be described. The connecting unit 45 includes a third biasing member 46, a holder 47 having the second valve seat member 41 fixed as a bottom to the inner periphery of a cylindrical side wall 47a, flanges 47b protruding outward from a pair of pillars 47c extending upward from opposing positions on the side wall 47a of the holder 47, and engaging portions 39d protruding outward from opposing positions on the bottom 39a of the frame 39 and having holes into which the flanges 47b can be inserted and hooked. A communication hole 47d opens between the pair of pillars 47c of the holder 47. The pillars 47c themselves also have a communication hole 47e.

[0059] The upper end of the holder 47 is open, and a lower portion of the third biasing member 46 is housed within the holder 47. The third biasing member 46 is sandwiched and compressed and held between the bottom portion 39a of the frame 39 and the bottom portion of the holder 47. The third biasing member 46 constitutes a holder biasing member that biases the holder 47 in a direction that keeps the flange 47b of the holder 47 hooked onto the engaging portion 39d of the frame 39.

[0060] Next, a method of assembling the thermostat device 4 will be described with reference to Fig. 6. As shown in Fig. 6(a), the support member 44 is inserted through the second biasing member 43, the central hole 42a of the second valve body 42, and the connecting hole 41b of the second valve seat member 41 fixed integrally as the bottom of the holder 47. The second valve seat member 41 integrated with the holder 47 is fixed to the support member 44 by rolling crimping so as to crush and spread the connecting protrusions 44a. In this manner, the differential pressure valve 40 integrated with the holder 47 is assembled.

[0061] 6(b), the first biasing member 38 is supported on the bottom 19a of the frame 19, and the temperature sensing portion 34 of the thermo-element 36 is inserted into the bottom opening 39b of the frame 39. The first biasing member 38 is sandwiched and pressed between the first valve body 32 fixed to the valve stem 33 and the bottom 19a. A protrusion 39e provided at the tip of the pillar portion 39c of the frame 39 is inserted into a hole 31e provided in the annular portion 31c of the first valve seat member 31 and crimped. The thermostat 30 is assembled in this manner.

[0062] Next, as shown in FIG. 6( c), the third biasing member 46 is sandwiched and compressed between the holder 47 integrated with the differential pressure valve 40 and the frame 39 of the thermostat 30. The pair of column portions 47c of the holder 47 are elastically deformed to insert the flanges 47b into the holes of the engaging portions 39d of the frame 39, and then the elastic deformation is released so that the hooks 47b engage with the engaging portions 39d. The third biasing member 46, as the holder biasing member, biases the hooks 47b in a direction that maintains their engagement with the engaging portions 39d. A gasket 48 made of an elastic material such as rubber is fitted around the outer periphery of the annular portion 31c. In this way, the thermostat device 4, in which the thermostat 30 and the differential pressure valve 40 are integrated, is assembled as shown in FIG. 6( d).

[0063] As shown in FIG. 4, when the thermostat device 4 is installed, the thermostat 30 is fixed to the partial passage 5a of the main passage 5, and the gasket 48 seals the thermostat 30 and the partial passage 5a.

[0064] The differential pressure valve 40 of the thermostat device 4 is inserted into the inlet of the bypass passage 6. The holder 47 integrated with the differential pressure valve 40 is pressed by the third biasing member 46 and comes into contact with the main passage 5 around the inlet of the bypass passage 6. At this time, the flange 47b is designed to be inserted into the hole of the engaging portion 39d but not in contact with the engaging portion 39d, i.e., to be floating above the engaging portion 39d. Therefore, even if there is a deviation in the position of the flange 47b or the engaging portion 39d due to dimensional tolerances, this can be tolerated. Furthermore, as long as the differential pressure valve 40 is inserted into the inlet of the bypass passage 6 and the holder 47 is grounded to the main passage 5 around the inlet while being pressed by the third biasing member 46, dimensional tolerances can be tolerated even if there are dimensional tolerances in the inner diameter of the inlet of the bypass passage 6 and the seating position of the holder 47, or if there are dimensional tolerances in the outer diameter of the differential pressure valve 40 and the outer diameter and height of the holder 47.

[0065] Next, the operation of the thermostat device 4 will be described. In Figure 4, the coolant in the main passage 5 flows into the frame 39 through the opening formed between the pair of pillars 39c, or flows into the holder 47 through the communication holes 47d and 47e. Therefore, the entire temperature sensing portion 34 of the thermo-element 36 can sense the temperature of the coolant.

[0066] When the coolant temperature sensed by the temperature sensing portion 34 is lower than a predetermined temperature, the wax in the temperature sensing portion 34 contracts, and the length of the portion of the piston 35 that protrudes from the valve stem portion 33 is minimized. In this case, the first valve body 32 is pressed by the first biasing member 38 to seat on the first valve seat member 31, the first opening 31a is closed, and the coolant does not flow from the main passage 5 to the partial passage 5a leading to the radiator.

[0067] In this case, when the pressure of the coolant is extremely small, the second valve body 42 of the differential pressure valve 40 is seated on the second valve seat member 41 by the second biasing member 43, but there is a gap 41c in the second opening 41a that is not closed by the second valve body 42. The coolant in the main passage 5 flows into the bypass passage 3 through the auxiliary passage 49 defined by the gap 41c.

[0068] 5, when the pressure of the coolant increases, the second valve body 42 is pressed down against the pressing force of the second biasing member 43, and the second opening 41a opens. The valve opening of the differential pressure valve 40 is controlled to a position where the pressure of the coolant and the pressing force of the second biasing member 43 are in equilibrium. The flow rate of the coolant flowing through the second opening 41a to the bypass passage 6 increases.

[0069] When the coolant temperature reaches a predetermined temperature or higher, the wax in the temperature sensing portion 34 senses the temperature and expands, increasing the length of the portion of the piston 35 that protrudes from the valve stem 33. However, the tip of the piston 35 is pressed by the piston receiver 37, so the first valve body 32, the valve stem 33, and the temperature sensing portion 34 descend together. As a result, the first valve body 32 descends against the pressing force of the first biasing member 38, opening the first opening 31a. As a result, the coolant that has flowed into the frame 39 flows from the first opening 31a, through the opening between the pair of arms 31d, and into the partial passage 5a of the main passage 5 that leads to the radiator. When the opening amount of the first valve body 32 increases, most of the cooling water flows into the partial passage 5a, and the cooling water pressure to the differential pressure valve 40 decreases, causing the second valve body 42 to seat on the second valve seat member 41. Since the second opening 41a has a gap 41c that is not closed by the second valve body 42, some of the cooling water in the main passage 5 flows into the bypass passage 3 through the auxiliary passage 49 defined by the gap 41c.

[0070] In the thermostat device 4, the flange 47b protruding outward from the holder 47 to which the second valve seat member 41 is fixed is caught by the engaging portion 39d provided on the frame 39. Furthermore, the holder biasing member, which is the third biasing member 38, is sandwiched and compressed between the frame 39 and the holder 47, and biases the flange 47b in a direction that maintains the flange 47b being caught by the engaging portion 39b. In this way, it is possible to obtain the thermostat device 4 in which the thermostat 30 and the differential pressure valve 40 are integrally connected, which easily tolerates dimensional tolerances of parts, is easy to assemble, and is easy to install in and replace in the main passage and the bypass passage.

[0071] Furthermore, by modifying an existing thermostat to a frame having the shape and structure of the frame 39 and further adopting the differential pressure valve 40 and the connecting unit 45, it is possible to easily modify the existing thermostat into a thermostat device with an integrated differential pressure valve.

[0072] The present invention is not limited to the above-described embodiments, but includes various modifications and equivalents that fall within the scope of the technical idea of ​​the present invention and its components.

[0073] 7, a thermostat device 7 according to another embodiment of the present invention is formed by integrally connecting a thermostat 50 having a housing 51 in which a first valve seat member, a piston receiver, and a frame are integrated, and the differential pressure valve 20 in which the holder 27 according to the first embodiment of the present invention is integrated, by a connecting unit 60. The connecting unit 60 includes the holder 27, a flange 27b protruding outward from the holder 27, a bottom frame 59a that can be fixed to the housing 51 and that constitutes an engaging portion on which the flange 27b is hooked when the holder 27 is inserted into an opening 59b, and a first biasing member 18 that constitutes a holder biasing member that biases the flange 27b of the holder 27 in a direction that keeps the flange 27b hooked on the engaging portion that is the bottom frame 59a.

[0074] The present invention can be used in a thermostat device that is mounted in an engine coolant circuit of an automobile.

[0075] DESCRIPTION OF SYMBOLS 1, 4, 7 Thermostat device 2, 2a, 5, 5a Main passage 3, 6 Bypass passage 10, 30, 50 Thermostat 11, 31 First valve seat member 11a, 31a First opening 12, 32 First valve body 13, 33 Valve stem portion 14, 34 Temperature sensing portion 15, 35 Piston 16, 36 Thermoelement 18 First biasing member (holder biasing member) 19, 39 Frame 19a, 39d, 59a Engagement portion 20, 40 Differential pressure valve 21, 41 Second valve seat member 21a, 41a Second opening 22, 42 Second valve body 23, 43 Second biasing member 24, 44 Support member 25 Push nut 26, 45, 60 Connecting unit 27, 47 Holder 27a, 47d, 47e: Communication holes 27b, 47b: Flanges 38: First biasing member 46: Third biasing member (holder biasing member)

Claims

1. A thermostat device to be mounted at a branch point between a main passage and a bypass passage, comprising: a thermostat for opening and closing the main passage; a differential pressure valve for opening and closing the bypass passage; and a connecting unit for connecting the thermostat and the differential pressure valve. The thermostat comprises: a first valve seat member having a first opening for communicating with the main passage; a first valve body that opens and closes the first opening by seating on and off the first valve seat member; a thermoelement having a valve stem portion to which the first valve body is fixed, a temperature sensing portion that is fixed to the base end of the valve stem portion and is filled with a material that expands or contracts according to temperature, and a piston that protrudes from the tip of the valve stem portion and moves forward and backward according to the expansion or contraction of the material; a first biasing member that biases the first valve body in a closing direction; and a frame that is fixed to the first valve seat member and supports the first biasing member. The differential pressure valve comprises: a second valve seat member having a second opening formed therein for communicating with the bypass passage; a second valve body that opens and closes the second opening by seating on and off the second valve seat member; a second biasing member that biases the second valve body in a closing direction; and a support member that is fixed to the second valve seat member and supports the second biasing member, wherein the connecting unit comprises: a holder that has a communication hole on a side surface and has the second valve seat member fixed to its inner periphery; a flange that protrudes outward from the holder; an engagement portion that is provided on the frame and on which the flange is hooked; and a holder biasing member that biases the holder in a direction to maintain the flange hooked on the engagement portion.

2. A thermostat device as claimed in claim 1, characterized in that the holder biasing member is a first biasing member which presses the flange protruding from the holder in a direction to maintain the flange hooked onto the engagement portion.

3. A thermostat device as claimed in claim 1, characterized in that the holder biasing member is a third biasing member which is different from the first biasing member and the second biasing member and which is sandwiched and compressed between the frame and the holder.

4. A thermostat device as claimed in claim 1, further comprising an auxiliary passage which always communicates from said main passage to said bypass passage when the device is installed.

5. A thermostat device according to claim 4, wherein said auxiliary passage is a gap between an inlet of said bypass passage and said holder inserted into said inlet.

6. A thermostat device as claimed in claim 4, characterized in that the auxiliary passage is a gap of the second opening which is not closed by the second valve body when the second valve body is seated on the second valve seat member.

Images