JPH0616788U - Variable valve temperature type thermostat - Google Patents

Abstract

(57) [Abstract] [Purpose] Not only can the structure be simple, compact and inexpensive to manufacture, it can be switched easily and quickly according to each specification, and the thermoelement can be fixed by always guiding the tip of the piston rod. (EN) To obtain a thermostat with a variable valve-opening temperature that stabilizes the temperature and prevents a decrease in life due to vibration. [Structure] A stepped portion 6 having one or more steps is provided at the tip of the piston rod 4, and the stopper 1 is attached to the thermostat main body in a stepped manner and abuts against the tip of the piston rod 4 to regulate its movement. An engaging portion 3 that can be engaged with the stepped portion 6 in a detachable manner and a guide portion 3a that guides the piston rod 6 are formed on the shaft.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an improvement of a thermostat which is provided in a cooling system of an internal combustion engine or the like and circulates the engine cooling liquid or the like as appropriate according to the temperature change of the cooling liquid filled in the cooling system to adjust the temperature of the engine cooling liquid or the like.

[0002]

[Prior art]

 Thermostats used in cooling systems such as internal combustion engines have a thermoelement that contains a thermal expansion body that expands and contracts due to changes in the temperature of the engine coolant that fills the cooling system. The piston rod is moved up and down to open and close the valve body, and the engine coolant and the like are appropriately circulated to keep the temperature of the engine coolant and the like constant.

FIG. 6 is a cross-sectional view illustrating the configuration of a general diaphragm type thermostat T used in a cooling system of an internal combustion engine and the like, and FIG. 7 is a partially enlarged view showing a tip end portion of a piston rod of the thermostat T. is there. Reference numeral 27 in FIG. 6 is a thermoelement containing a thermal expansion body 31 such as wax. The tip of the slidable piston rod 30 of the thermoelement 27 is, as shown in FIG. It abuts on the stopper 28 fixed to the flange 29. Therefore, when the temperature of the engine coolant or the like rises and the thermal expansion body 31 expands, a force acts on the piston rod 30 in a direction to push it out from the thermoelement 27 via the diaphragm 35, but the tip of the piston rod 30 is Since the movement of the thermoelement 27 is restricted by the stopper 28, the other portion of the thermoelement 27 except the piston rod 30 moves. Since the valve body 36 is integrally attached to the piston guide 34 of the thermoelement 27, the thermostat T is opened apart from the valve seat 37 due to the expansion of the thermal expansion body 31.

FIG. 7B shows another form of the tip end portion of the piston rod. The tip end portion of the piston rod 36 is formed as a small diameter portion 37, and the small diameter portion 37 is inserted into the stopper 35. The tip 27a is caulked to fix the tip of the piston rod 36 to the stopper 35.

By the way, the temperature of the coolant for opening the thermostat T to start the circulation of the engine coolant or the like needs to be changed according to the environment in which the device such as the internal combustion engine is used, in particular, the ambient temperature. For example, in cold district specifications, the valve opening timing of the thermostat must be delayed so that the coolant temperature is higher than the standard specifications. On the other hand, in tropical regions, contrary to the above, the thermostat valve opening timing must be advanced so that the coolant temperature becomes lower than the standard specifications. Therefore, conventionally, the type of wax used as a thermal expansion body was changed to set the valve opening timing of the thermostat depending on whether it is a cold area specification or a tropical area specification, but for each specification, the thermostat opening time is set. The settings were fixed and irrationality occurred.

Therefore, the applicant of the present application has disclosed a thermostat capable of adjusting the valve opening timing by detecting the outside air temperature in Japanese Patent Laid-Open No. 57-33276. Further, Japanese Utility Model Laid-Open No. 59-137322 discloses a thermostat in which the valve opening timing can be adjusted by vertically moving the stopper position of the thermoelement using a diaphragm device. However, such a thermostat has a problem that the structure is complicated and thus the manufacturing cost is high, and the thermostat is also large and requires a large mounting space. Also, since the piston rod is not guided until the tip of the piston rod moves and comes into contact with the stopper, the fixation of the thermoelement becomes unstable during that time, and vibration during operation shortens the life of the thermostat. There was a problem.

[0007]

[Problems to be solved by the device]

 The present invention has been made in view of the above-mentioned problems, and the purpose thereof is not only that the structure is simple, and that it can be manufactured at a small size and at low cost, and that switching can be performed easily and quickly according to each specification. By constantly guiding the tip of the piston rod, it is possible to obtain a thermostat with a variable valve temperature that can stabilize the thermoelement and prevent the life from being shortened due to vibration.

[0008]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, the valve opening variable temperature type thermostat of the present invention is provided in a cooling system of an internal combustion engine or the like, and has a built-in thermal expansion body which expands or contracts due to a temperature change of the engine coolant or the like. However, in a thermostat that has a piston rod that slides due to the thermal expansion and contraction of the thermal expansion body, and that opens and closes the on-off valve by sliding the piston rod with the volume change of the thermal expansion body, The front end is provided with one or more stepped portions, and is attached to the thermostat body, and a stopper that abuts on the tip end portion of the piston rod and restricts its movement is detachable from the stepped portion. It is characterized in that an engaging portion that can be engaged and a guide portion that guides the piston rod are formed.

[0009]

[Action]

 Since the present invention is configured as described above, it operates as follows. For example, when switching the thermostat from the standard specification to the cold area specification, the stepper part of the piston rod and the engagement part of the stopper can be engaged by releasing the engagement between the stopper and the tip of the piston rod. To be in a good state. When the temperature of the engine coolant rises, the tip of the piston rod slides while being guided by the guide of the stopper. When the stepped portion of the piston rod engages with the engagement portion of the stopper, the movement of the piston rod is restricted, so that the valve body separates from the valve seat and the thermostat opens. That is, the opening timing of the thermostat is delayed and the coolant temperature rises.

[0010]

【Example】

 Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In the drawings, the same members and parts as those of the conventional example are designated by the same reference numerals and detailed description thereof will be omitted. [First Embodiment] FIG. 1 is a schematic view for explaining the configuration and operation of the first embodiment of the present invention. FIG. 1 (a) shows a standard specification state, and FIG. 1 (b) shows a cold region specification. It shows the switched state. In the figure, reference numeral 4 is a piston rod, and reference numeral 1 is a stopper which is attached to a flange 29 of the thermostat T and which restricts the movement of the piston rod 4. At the tip of the piston rod 4, a small-diameter portion 5 concentric with the piston rod 4 is formed by scraping off the outer circumference, and the portion where the outer diameter of the small-diameter portion 5 and the outer circumference of the piston rod 4 changes is stepped. It is formed as part 6. On the other hand, the stopper 1 has a two-part configuration of an upper stopper 2 and a lower stopper 3. The lower stopper 3 has a through hole 3a as a guide portion through which the small diameter portion 5 at the tip of the piston rod can be inserted, and the upper stopper 2 has a through hole 3a. A concave bottom portion 2a with which the tip of the piston rod 4 can come into contact is formed, and the upper stopper 2 is screwed to the lower stopper 3 fixed to the flange 29.

In the standard specification (for example, the valve opening temperature is 82 degrees), the tip of the piston rod 4 is in contact with the concave bottom portion 2a of the upper stopper 2, and the valve body 36 moves when the coolant temperature reaches 82 degrees. The thermostat T is opened away from the valve seat 37 (see FIG. 5), and circulation of the engine cooling liquid or the like becomes possible. When the upper stopper 2 is removed from the lower stopper 3 in order to switch from the standard specification to the cold district specification (for example, the valve opening temperature is 88 degrees), the piston rod 4 and the upper stopper 2 are disengaged and the stepped portion is released. 6 and the lower stopper 3, which is an engaging portion, can be engaged. When the coolant temperature rises to reach 82 degrees, the piston rod 4 slides while being guided by the inner peripheral surface of the through hole 3a. The thick arrow in the figure indicates the direction of the force urged by the piston rod 4 due to the expansion of the thermal expansion body 31 (see FIG. 6). When the piston rod 4 moves by the distance indicated by h in Fig. 1 (b) and the stepped portion 6 comes into contact with the lower stopper 3, the movement of the piston rod 4 is restricted and the thermostat T is opened to cool the engine. Circulation of liquid etc. begins. Here, if the lift amount of the piston rod 4 due to the change in the coolant temperature is measured in advance, the moving distance h with respect to the desired valve opening temperature can be determined. For example, assuming that the lift amount of the piston rod 4 with respect to a temperature difference of 6 degrees of engine cooling liquid is 2 mm, if the moving distance h when the upper stopper 2 is removed is set to 2 mm, the valve opening will occur. It is possible to obtain a cold region type thermostat having a temperature of 88 degrees.

Although the upper stopper 2 is screwed to the lower stopper 3 in this embodiment, it is sufficient that the upper stopper 2 and the lower stopper 3 are detachable. It goes without saying that other means such as stopping can be used. Further, in the above embodiment, the case of switching from the standard specification to the cold area specification has been described, but the thermostat is manufactured so that the valve opening temperature of the thermostat with the upper stopper 2 attached becomes the tropical area specification (for example, 76 degrees). If so, by removing the upper stopper 2, the valve opening temperature rises, and it is possible to switch to the standard specification of the valve opening temperature of 82 degrees.

[Second Embodiment] FIG. 2 is an explanatory view of the operation according to a second embodiment of the present invention, and FIG. 3 is a perspective explanatory view showing the shape of the tip of the piston rod in FIG. As shown in FIG. 3, in this embodiment, a small-diameter portion 10 concentric with the piston rod 8 is formed at the tip of the piston rod 8, and a part of the outer circumference of the small-diameter portion 10 is shaved off to form a parallel surface 10a. , 10a are formed. Further, a shaft body 9 extending in the axial direction of the piston rod 8 is provided from the small diameter portion 10, and a recessed portion 9a with which a driver 16 or the like can be engaged is formed at the tip thereof.

As shown in FIG. 2, a holding member 15 is inserted into the tip of the shaft body 9 to prevent the ring 9 b from coming off, and between the holding member 15 and the flange 29. The coil spring 14 is press-fitted so that the elastic force is constantly applied. The portions where the outer diameters of the shaft portion 9 and the small diameter portion 10 and between the small diameter portion 10 and the outer circumference of the piston rod 8 change are formed as stepped portions 10b and 11, respectively. On the other hand, the stopper 12 fixed to the flange 29 serves as a large-diameter portion 13 into which the small-diameter portion 10 can be fitted, and a guide portion that is formed in substantially the same shape as the small-diameter portion 10 and can be fitted to the small-diameter portion 10. The fitting hole 17 is formed. Further, between the large diameter portion 13 and the fitting hole 17, an engaging portion 18 that can engage with the stepped portion 10b or the stepped portion 11 of the piston rod 8 is formed.

In a standard specification (for example, a valve opening temperature of 82 degrees), the small-diameter portion 10 is fitted in the large-diameter portion 13 so that the stepped portion 10b and the engaging portion 13 of the stopper 12 are engaged with each other. When the liquid temperature reaches 82 ° C., the valve body 36 separates from the valve seat 37 (see FIG. 5) and the thermostat T is opened to allow circulation of the engine cooling liquid or the like. When the piston rod 8 is rotated about 90 degrees using the driver 16 etc. to switch from the standard specification to the cold area specification (for example, the valve opening temperature is 88 degrees), the small diameter portion 10 and the fitting hole 17 are aligned. Part of the small-diameter portion 10 is fitted into the fitting hole 17, the engagement between the stepped portion 10b and the engaging portion 18 is released, and the engagement between the stepped portion 11 and the engaging portion 18 is released. Is possible.

When the coolant temperature rises and exceeds 82 degrees, the small diameter portion 10 of the piston rod 8 moves while being guided along the inner peripheral surface of the fitting hole 17. Then, when the piston rod 8 moves by a distance indicated by h in FIG. 2B and the large diameter portion 18 comes into contact with the stepped portion 11, the thermostat T opens to circulate the engine coolant or the like. Begins. Here, by selecting the moving distance h as in the case of the first embodiment, it is possible to obtain a cold region type thermostat having a valve opening temperature of 88 degrees. Further, as in the case of the first embodiment, if the valve opening temperature of the thermostat in the state where the stepped portion 10b and the engaging portion 18 are engaged is set as tropical zone specifications (for example, valve opening temperature 76 degrees), By making the stepped portion 11 and the engaging portion 18 engageable with each other, it is possible to switch to the standard specification of the valve opening temperature of 82 degrees.

[Third Embodiment] FIGS. 4 and 5 are schematic views showing a third embodiment of the present invention. As shown in FIG. 4, in this embodiment, the engaging member 22 is attached to the tip end portion of the piston rod 26, and the engaging member 22 and the stopper 20 are fitted together.

FIG. 5 is a partially cutaway perspective view of the stopper 20 and the engaging member 22. The engaging member 22 has four protrusions 24, 24, which are stepped portions, formed at equal intervals on the outer periphery of the base of the cylindrical body 23 (the other side does not appear in the figure), and the through hole 25 The piston rod 26 can be fixed to the piston rod 26 by inserting the tip portion and caulking the tip portion. On the other hand, in the through hole 21 of the stopper 20 fixed to the flange 29 of the thermostat, the large diameter portion 21a into which the base portion of the cylindrical body 23 in which the projections 24, 24 ... A small diameter portion 21b that can be fitted is formed. The small-diameter portion 21b is provided with an engagement groove 21d as a guide portion that can be engaged with the projection 24 and can slide along the inner circumferential surface of the groove, and is cut from the large-diameter portion 21a to a certain depth. Further, a portion where the inner diameter of the large diameter portion 21a and the small diameter portion 21b changes is formed as an engaging portion 21c which can be engaged with the protrusions 24 ,.

In the standard specification (for example, the valve opening temperature is 82 degrees), the protrusions 24, 24, ... Of the engaging member 22 are engaged with the engaging portion 21c of the stopper 20, and the coolant temperature is 82 degrees. When it reaches, the valve body 36 separates from the valve seat 37 (see FIG. 5) and the thermostat T opens, allowing the circulation of the engine coolant and the like. When the engaging member 22 is rotated about 45 degrees with respect to the stopper 20 in order to switch from the standard specification to the cold district specification (for example, the valve opening temperature of 88 degrees), the projections 24, 24, ... Disengage from the engaging section 21c. To engage the engaging groove 21d.

When the coolant temperature rises to 82 degrees in this state, the projections 24, 24, ... Slide along the inner peripheral surface of the engagement groove 21d, so that the engagement member 22 slides. At the same time, the tip of the piston rod 8 moves to the small diameter portion 21b side. When the tip of the piston rod 8 moves by a predetermined distance and the projections 24, 24, ... Abut the groove end of the engaging groove 24d, the thermostat T opens to start circulation of the engine coolant or the like. . Here, if the distance that the piston rod moves is selected as in the case of the first embodiment, it is possible to obtain a cold region type thermostat with a valve opening temperature of 88 degrees. Further, similarly to the case of the first embodiment, if the state in which the projections 24, 24, ... Are engaged with the engaging portion 21c is set as the tropical land specification, the engaging member 22 is rotated and the projections 24, 24 are rotated. By engaging .. with the engaging groove 21d, the valve opening temperature of the thermostat T rises and the standard specification can be switched.

Although the preferred embodiment of the present invention has been described, a plurality of stepped portions are provided at the tip of the piston rod, and an engaging portion that can engage with each of the stepped portions is formed on the stopper side. As a result, a single thermostat can be used to switch from a tropical area specification to a standard specification or a cold area specification in multiple stages, thus improving the versatility of the thermostat.

[0022]

[Effect of device]

 Since the thermostat of the present invention is configured as described above, it has the following effects. Since it is possible to easily and quickly switch from the standard specifications to different specifications such as tropical areas or cold areas, the versatility of one thermostat is improved, and the labor required to reduce the number of parts and design changes is reduced. Manufacturing costs can be reduced. In addition, since the structure is extremely simple, the thermostat can be made small and can be manufactured at a low price. Further, since the tip of the piston rod is always guided by the guide part, the thermoelement can be stably fixed, and it is possible to effectively prevent the thermoelement from breaking down or shortening its life due to vibration during operation. .

[Brief description of drawings]

FIG. 1 is a schematic diagram illustrating the configuration and operation of a first embodiment of the present invention, in which (a) shows a standard specification state,
(B) is a diagram showing a state where the specification is switched to the cold district.

FIG. 2 is a schematic diagram illustrating the configuration and operation of the second embodiment of the present invention, in which (a) shows a standard specification state,
(B) is a diagram showing a state where the specification is switched to the cold district.

FIG. 3 is an enlarged perspective view of a tip end portion of a piston rod according to a second embodiment of the present invention.

FIG. 4 is a sectional explanatory view of the configuration according to the third embodiment of the present invention.

FIG. 5 is a perspective explanatory view of a stopper and an engaging member according to a third embodiment of the present invention.

FIG. 6 is a cross-sectional view illustrating the configuration of a general diaphragm type thermostat used in an internal combustion engine or the like.

FIG. 7 is a schematic explanatory view showing a shape of a tip of a piston rod according to a conventional thermostat.

[Explanation of symbols]

 1,12,20 Stopper 2 Upper stopper 3 Lower stopper (engagement part) 3a Through hole (guide part) 4,8,26 Piston rod 5 Small diameter part 6,10b, 11,24 Stepped part 17 Fitting hole (guide 21d Engaging groove (guide) 21c, 18 Engaging part 29 Flange

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Creator Shiorizawa Shiorizawa 6-59 Nakazato, Kiyose-shi, Tokyo 2 Japan Thermostat Co., Ltd. (72) Creator Mitsumasa Matsumoto 1-1 Daihatsu-cho, Ikeda-shi, Osaka Daihatsu Kogyo Co., Ltd. (72) Creator Koji Fukushima 1-1 Daihatsu-cho, Ikeda-shi, Osaka Daihatsu Kogyo Co., Ltd.

Claims (1)

[Scope of utility model registration request] 1. A piston rod which is provided in a cooling system such as an internal combustion engine, has a built-in thermal expansion body that thermally expands or contracts according to a temperature change of a cooling liquid, and has a piston rod that slides due to thermal expansion or contraction of the thermal expansion body. However, in a thermostat that opens and closes the on-off valve by sliding the piston rod with the volume change of the thermal expansion body, one or more stepped portions are provided at the tip end portion of the piston rod, and stepwise The stopper attached to the thermostat body and restricting the movement of the piston rod by contacting the tip end portion of the piston rod includes an engaging portion that can engage with the stepped portion in a disengageable manner and a guide portion that guides the piston rod. A thermostat with a variable valve opening temperature that is characterized by being formed.