JP3208283B2 - Cylinder head cooling water passage structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling water passage structure of a cylinder head, and more particularly to a cooling water passage structure of a cylinder head in which a cooling water passage on an intake side and a cooling water passage on an exhaust side are formed separately from each other. Things.

[0002]

2. Description of the Related Art In recent years, as disclosed in, for example, Japanese Utility Model Application Laid-Open No. 2-63052, cooling water from a radiator is supplied to a cylinder head in order to increase cooling efficiency with respect to intake air and improve intake volume efficiency. A cooling water passage structure in which the water is supplied to the cooling water passage of the cylinder block by a water pump after passing through the cooling water passage on the side, and the cooling water passage of the cylinder block returns to the radiator through the cooling water passage on the exhaust side of the cylinder head. Has been proposed.

In a cylinder head 31 having such a cooling water passage structure, as shown in FIG. 4, a cooling water passage 32 on the intake side and a cooling water passage 33 on the exhaust side are formed separately. The inlet 3 of the cooling water passage 32 on the intake side
A communication opening 35 for bypass is formed in a partition wall 34 between the outlet 2a and the outlet 33a of the cooling water passage 33 on the exhaust side, and a thermostat 36 having an on-off valve 37 for opening and closing the communication opening 35 is provided at the inlet 32a. When the temperature of the cooling water is low, the cooling water is not passed from the outlet 33a of the cooling water passage 33 to the radiator and the inlet 32 of the cooling water passage 32 on the intake side is provided.
There is also known a device that bypasses and circulates a.

In general, a thermostat for circulating the cooling water so as to bypass the radiator when the temperature of the cooling water is low is disclosed in, for example, Japanese Utility Model Laid-Open No. 55-1634.
No. 28, for example.

In order to improve the responsiveness of the thermostat 36, a separate baffle plate 38 is attached to the thermostat 36 so that the cooling water bypassed through the communication opening 35 flows through the temperature sensing portion 36a of the thermostat 36 without fail. Is also known.

FIG. 3 shows the details of the mounting state of the baffle plate 38 by phantom lines. Further, the thermostat 36 is provided with a small valve element for bleeding air called a jiggle pin (not shown), and a positioning means for attaching the thermostat 36 so that the jiggle pin is located at an upper portion is required. An engagement portion 39 for engaging the lower support arm 36b of the thermostat 36 is formed on the cylinder head 31 side.

In FIG. 4, the intake-side cooling water passage 32
Is formed so as to protrude from the other end of the cylinder head 1, and a connection port 41 for a suction port of a water pump provided in a cylinder block (not shown) is opened downward. The exhaust-side cooling water passage 33 is connected to a cooling water passage formed in a cylinder block (not shown) via a communication port 42 on the lower surface of the cylinder head 31. An outlet 33a of the exhaust-side cooling water passage 33 is The cooling water outlet 43 is provided at one end of the cylinder head 31 and connected to the inlet of the radiator.

[0008]

However, as described above, since the baffle plate 38 is separately attached to apply the cooling water to the temperature sensing portion 36a of the thermostat 36, the number of parts and the number of processing steps are increased. There is a problem that the cost increases. In addition, there is a problem that the cost is increased because the positioning engagement portion 39 of the thermostat 36 needs to be processed.

The present invention has been made in view of the above-mentioned conventional problems, and the cooling water to be bypassed is surely guided toward the thermosensitive part of the thermostat, and has a good responsiveness. It is an object of the present invention to provide a cylinder head cooling water passage structure that can be configured at low cost.

[0010]

According to the present invention, a cooling water passage on the intake side and a cooling water passage on the exhaust side are formed separately from each other, and an inlet of the cooling water passage on the intake side and a cooling water passage on the exhaust side. In the cooling water passage structure of the cylinder head, a communication opening for bypass is formed between the ends of the cylinder head, and a thermostat having a valve body for opening and closing the communication opening is disposed at an inlet of the cooling water passage on the intake side. A bowl-shaped plug that forms the valve seat of the valve body is fitted and fixed to the communication opening, and a part of the bowl-shaped plug on the intake-side cooling water passage side passes through the communication opening to the intake-side cooling water passage. A guide wall portion for guiding flowing cooling water to a temperature sensing portion of the thermostat is extended, and a notch for regulating a circumferential position of the thermostat by engaging the thermostat with the bowl-shaped plug is provided.

[0011]

According to the present invention, a valve seat is formed by fitting and fixing a bowl-shaped plug into a communication opening between the inlet of the cooling water passage on the intake side and the end of the cooling water passage on the exhaust side. Therefore, the communication opening can be formed with a large diameter, and in order to form a cooling water passage separated on the intake side and the exhaust side, a single core in which those cores are integrally connected at the communication opening portion is used. It can be used, and the manufacturing cost of the core can be significantly reduced as compared with the case where a separate core is used. In addition, since the connecting portion has a large diameter, high productivity can be secured for producing the core. Since the guide wall that extends the cooling water to the thermosensitive part of the thermostat is extended on the bowl-shaped plug, there is no need to provide additional parts such as baffles, and thus the cost is not increased. Ensure that cooling water bypasses toward the thermosensitive part of the thermostat Can, it is possible to improve the responsiveness of the thermostat.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS.

In FIG. 1, reference numeral 1 denotes a cylinder head, on which an intake-side cooling water passage 2 is provided on the intake port side, and an exhaust-side cooling water passage 3 is provided on the exhaust port side. An inlet 2a of the intake-side cooling water passage 2 located at one end of the cylinder head 1 is communicated with a cooling water inlet 4 connected to an outlet of the radiator, and a thermostat 5 is arranged over the cooling water inlet 4 and the inlet 2a. ing. An outlet (not shown) of the intake-side cooling water passage 2 is connected to a suction port of a water pump provided in the cylinder block. The exhaust-side cooling water passage 3 is connected to a cooling water passage formed in the cylinder block through a communication port (not shown) on the lower surface of the cylinder head 1. The head 1 is connected to a cooling water outlet 6 provided at one end of the head 1 and is connected to an inlet of a radiator.

A partition wall 7 between the inlet 2a of the cooling water passage 2 on the intake side of the cylinder head 1 and the outlet 3a of the cooling water passage 3 on the exhaust side has a large diameter coaxial with the cooling water inlet 4. A communication opening 8 is formed. The communication opening 8 is formed into a stepped hole having a stepped surface 8a by machining a casting hole formed by the core, and the communication opening 8 is provided with a valve port 9 serving as a bypass passage hole and a peripheral portion thereof. A bowl-shaped plug 11 having a valve seat 10 is fitted and fixed.

As shown in FIG. 2, the bowl-shaped plug 11 is formed into a stepped cup shape having a large-diameter opening 11a and a small-diameter bottom 11b, and the outer periphery of the bottom 11b is press-fitted into the communication opening 8. With opening 11a and bottom 11b
Are engaged with the step surface 8a, and the bottom surface 1c
A valve port 9 and a valve seat 10 are formed in 1d. A guide wall portion 12 extends in an arc shape from substantially half the circumference of the edge of the opening 11a of the bowl-shaped plug 11, and a cutout portion 13 is formed at the center of the edge in the circumferential direction.

The thermostat 5 is, as shown in FIG.
A body frame 15 having a seal body 14 around the periphery and a valve port 15a at the center, a lower frame 17 supported by a pair of lower support arms 16 suspended downward from the body frame 15, and a lower frame 1
7 and a cooling water inlet 4 mounted on an upper part of an operation shaft 19 extending vertically from the temperature sensing part 18.
And a second valve body 21 attached to the lower portion of the operating shaft 19 to open and close the valve port 9 of the communication opening 8.

The thermostat 5 is connected to the cylinder head 1
The lower support arm 16 is fitted into the notch 13 of the bowl-shaped plug 11 in a state where the thermostat 5 is mounted on the cooling water inlet 4 to regulate the circumferential position in the mounted state of the thermostat 5. The air bleeding jiggle pin (not shown) is located at the top.

In the above-described configuration, in the normal operating state of the engine, the operating shaft 19 of the thermostat 5 moves downward, the first valve body 20 opens, and the radiator returns from the cooling water inlet 4 to the intake side cooling water passage 2. Since the cooling water is introduced and the valve port 9 is closed by the second valve body 21, the cooling water does not bypass from the outlet 3 a of the exhaust-side cooling water passage 3 toward the intake-side cooling water passage 2. Spills towards the radiator.

When the cooling water is being warmed up at a low temperature, the temperature sensing portion 18 of the thermostat 5 operates to move the operating shaft 19 upward, so that the cooling water inlet 4 is closed by the first valve body 20 and the cooling water inlet 4 is closed. The two-valve element 21 is separated from the valve seat 10 of the bowl-shaped plug 11 to open the valve port 9, and the cooling water at the outlet 3 a of the exhaust-side cooling water passage 3 is drawn from the valve port 9 through the inside of the bowl-shaped plug 11. The cooling water flows into the inlet 2a of the side cooling water passage 2 and circulates between the exhaust side cooling water passage 3 and the intake side cooling water passage 2 bypassing the radiator. Further, since the cooling water passing through the inside of the bowl-shaped plug 11 is guided by the guide wall portion 12 and is surely guided to the temperature sensing portion 18 of the thermostat 5 and flows, the thermostat 5 can ensure good responsiveness. .

A bowl-shaped plug 11 is fitted and fixed in a communication opening 8 between an inlet 2a of the intake-side cooling water passage 2 and an outlet 3a of the exhaust-side cooling water passage 3 to form a valve seat 10. In this case, the communication opening 8 can be formed with a large diameter, and the cooling water passages 2 and 3 on the intake side and the exhaust side can be manufactured using a single core and separate cores are used. In addition to the above, the manufacturing cost of the core can be significantly reduced, and the use of the bowl-shaped plug 11 allows the connecting portion to have a large diameter, thereby ensuring high productivity in producing the core. By forming the guide wall portion 12 in such a bowl-shaped plug 11, it is possible to increase the responsiveness of the thermostat 5 as described above without providing a separate component such as a baffle plate, thereby increasing the cost. .

Further, a notch 13 is formed in the guide wall portion 12, and the lower support arm 16 of the thermostat 5 is fitted and engaged to regulate the circumferential position of the thermostat 5 in the mounted state. The thermostat 5 can be positioned so that the jiggle pin is located at the upper portion, and it is not necessary to process the engaging portion for positioning on the cylinder head or the like, so that the cost can be reduced.

[0022]

According to the cooling water passage structure of the cylinder head of the present invention, the bowl-shaped communication opening between the inlet of the cooling water passage on the intake side and the end of the cooling water passage on the exhaust side as described above. Since the valve seat is formed by fitting and fixing the plug, the communication opening can be formed with a large diameter, and when forming the cooling water passage separated on the intake side and the exhaust side, A single core united together at the communication opening can be used, and the manufacturing cost of the core can be greatly reduced compared to the case where separate cores are used, and the connecting part has a large diameter. High productivity can be ensured to produce the core, and the bowl-shaped plug has a guide wall that extends the cooling water to the thermosensitive part of the thermostat. Thermostat without the need for additional parts and therefore without cost Can guide the cooling water to bypass toward the temperature sensing portion securely, it is possible to improve the responsiveness of the thermostat.

[Brief description of the drawings]

FIG. 1 is a cross-sectional plan view of a main part of a cooling water passage structure of a cylinder head according to an embodiment of the present invention.

2A and 2B show the bowl-shaped plug of the embodiment, wherein FIG. 2A is a plan view, FIG. 2B is a front view, and FIG. 2C is a side view.

3A and 3B show the thermostat of the embodiment, wherein FIG. 3A is a longitudinal front view and FIG. 3B is a side view.

FIG. 4 is a cross-sectional plan view of a cooling water passage structure of a conventional cylinder head.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder head 2 Intake side cooling water passage 3 Exhaust side cooling water passage 5 Thermostat 8 Communication opening 10 Valve seat 11 Bowl-shaped plug 12 Guide wall part 18 Temperature sensing part 21 Second valve body

──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. ⁷ identification code FI F02F 1/40 F02F 1/40 C (58) Field surveyed (Int. Cl. ⁷ , DB name) F01P 3/02 F01P 7 / 16 502 F02F 1/40

Claims (1)

(57) [Claims] 1. A cooling water passage on an intake side and a cooling water passage on an exhaust side are formed separately from each other, and a bypass passage is provided between an inlet of the cooling water passage on the intake side and an end of the cooling water passage on the exhaust side. In the cooling water passage structure of the cylinder head in which a communication opening is formed and a thermostat provided with a valve body for opening and closing the communication opening is provided at an inlet portion of the cooling water passage on the intake side, the valve of the valve body is provided in the communication opening. The bowl-shaped plug forming the seat is fitted and fixed, and a part of the bowl-shaped plug on the side of the cooling water passage on the intake side is
A guide wall is provided to guide the cooling water flowing through the communication opening to the cooling water passage on the intake side to the thermosensitive part of the thermostat .
By engaging the thermostat with the bowl-shaped plug,
A cooling water passage structure for a cylinder head, wherein a notch for regulating a circumferential position of the mostostat is provided .