JPH0444815Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to a cooling water passage structure for an engine.

(Prior art) In a water-cooled engine, a thermostat that opens and closes depending on the cooling water temperature is installed between the cooling water passage on the engine body side and the radiator. Cooling water is circulated bypassing the radiator to promote warm-up, and conversely, in operating regions where the coolant temperature is high, the coolant is circulated to the radiator side to promote engine cooling.

By the way, this thermostat usually has a valve body that selectively opens and closes the cooling water passage on a shaft member that moves forward and backward in the axial direction in response to volume changes due to thermal expansion and contraction of a variable volume temperature sensing member such as wax. When installed, the shaft member is slidably supported by a guide member, and the valve body selectively opens and closes the cooling water passage according to the forward and backward movement of the shaft member, thereby cooling the water passage. In addition to switching the water circulation path, by supporting the shaft member with the guide member, it is possible to prevent the valve body from seating improperly due to the inclination of the shaft member (for example, in actual use). (See Publication No. 55-140713).

However, generally around a thermostat, a cooling water passage is constructed so that the cooling water flows from a direction perpendicular to the axial direction of the shaft member of the thermostat and toward the axial center of the shaft member. . Therefore, the dynamic pressure of the cooling water is constantly acting on the shaft member of the thermostat in a direction that causes the shaft member to tilt toward the downstream side of the cooling water. In this case, if the pressure pulsation of the cooling water is small and the shaft member is stopped, no major problems will occur.
℃), the valve body frequently repeats seating and separation actions, resulting in high-level pressure pulsations.As a result, the shaft member is repeatedly subjected to large dynamic pressure, causing uneven contact with the guide member. Repeated sliding contact causes the shaft member, which is made of a relatively soft material such as copper, to wear unevenly, and in some cases, seizure may occur between the shaft member and the guide member, causing the thermostat to malfunction. There is a risk that the engine will become inoperable (i.e., a stuck thermostat), resulting in, for example, an overheating condition or a poor warm-up condition of the engine.

(Purpose of the invention) The present invention is an attempt to solve the problems pointed out in the above-mentioned section of the prior art. In an engine having a passage configuration in which a cooling water passage is configured to flow from the ground toward the axis of the shaft member, uneven wear of the shaft member due to the dynamic pressure of the cooling water is suppressed as much as possible. The purpose of this is to prevent the occurrence of the thermostat sticking phenomenon.

(Means for Achieving the Object) In the present invention, as a means for achieving the above object, there is provided a shaft member that is moved forward and backward in the axial direction according to a change in the volume of the temperature-sensitive member, and a shaft member that is attached to the shaft member. A thermostat having a valve body that opens and closes as the shaft member moves forward and backward, and a guide member that slidably supports the shaft member is disposed in the cooling water passage of the engine, and the thermostat is connected to the engine cooling water. In an engine in which the cooling water is made to flow from a direction perpendicular to the axial direction of the shaft member of the thermostat toward the shaft member, the cooling water is placed at a position upstream of the shaft member of the thermostat. A deflection guide wall is provided which has a generally wedge-shaped cross section in the inflow direction and acts to deflect and guide the cooling water flow flowing toward the shaft member toward the outer circumferential side of the shaft member.

(Function) In the present invention, by the above means, the cooling water flowing toward the shaft member of the thermostat is deflected by the deflection guide wall provided on the upstream side of the cooling water from the thermostat, and Since the cooling water is guided toward the outer circumference, the dynamic pressure of the cooling water acts almost uniformly on the shaft member from the entire outer circumference, and the dynamic pressure of the cooling water causes the shaft member to tilt, causing the shaft member to tilt. This will prevent uneven contact with the guide member as much as possible.

(Embodiment) Hereinafter, a preferred embodiment of the present invention will be described with reference to FIGS. 1 to 3.

1 to 3 show the main parts of the cooling system of an automobile engine equipped with a cooling water passage structure according to an embodiment of the present invention, and in each figure, reference numeral 1
is a thermostat fitting chamber 11 formed therein.
This is a thermostat housing into which a thermostat 4, which will be described later, is fitted. This thermostat housing 1 is fastened and fixed to an end face 2a of a cylinder head 2 of an engine, and the thermostat housing 1 has an opening on the fastening face 1a and a communication passage 13 connected to the above-mentioned housing on the fastening face 1a side. A cooling water inlet passage 12 communicating with the thermostat fitting chamber 11 is formed. This cooling water inlet passage 12 is connected to the cylinder head 2 when it is fastened to the cylinder head 2.
The cooling water outlet passage 25 opens on the end surface 2a of the cooling water outlet passage 25.

Furthermore, the thermostat fitting chamber 11 includes a first cooling water passage 21 formed by a cooling water pipe 3 that is fastened to the opening end 11a and also functions as a cover member for the thermostat 4, which will be described later. It is communicated with a second cooling water passage 22 that opens at the bottom 11b of the thermostat fitting chamber 11. Note that the other end surface 2a of the first cooling water passage 21 is connected to an upper tank side of a radiator (not shown). The other end of the second cooling water passage 22 passes through the lower part of the cooling water inlet passage 12 and is opened to the fastening surface 1a. It is connected to the circulation passage 26.

Therefore, the cooling water outlet passage 2 of the cylinder head 2
5 is connected to the radiator via the thermostat fitting chamber 11 of the thermostat housing 1 and the cooling water pipe 3, and at the same time is connected to the cooling water circulation passage via the thermostat fitting chamber 11 and the second cooling water passage 22. 26, and the thermostat 4, which will be described later, switches between the two cooling water passages.
It is becoming more and more common to do so.

As shown in FIG. 1, the thermostat 4 is installed in a thermostat case 41 made up of an upper bracket 45 and a lower bracket 46, and has a temperature-sensitive member such as wax that is attached in an axial direction relative to a fixed member 44 due to a change in volume of a temperature-sensitive member such as wax. A shaft member 43 that is made to expand and contract,
It is attached to the lower bracket 46 so as to be slidably supported in the axial direction by a cylindrical guide member 42 provided on the lower bracket 46. Further, on the upper part of this shaft member 43, there is a first valve body 51 that is seated on or separated from a first valve port 53 constituted by the inner surface of the upper bracket 45.
A second valve element 52 is attached to the lower part of the cooling water passage 22, respectively, so that the second valve element 52 is seated on or separated from a second valve port 54 formed at the open end of the second cooling water passage 22. Therefore, when the thermostat 4 is fitted into the thermostat fitting chamber 11 of the cylinder head 22, the first cooling water passage 21 is opened by the first valve body 51 of the thermostat 4. ,
Further, the second cooling water passage 22 is selectively opened and closed in conjunction with the displacement of the shaft member 43 by the second valve body 52, so that the two cooling systems correspond to the cooling water temperature. It is considered to be valid as an alternative.

By the way, when the engine is operated, the cooling water W is pumped by a water pump (not shown).
As shown in FIG. 1, from the cooling water outlet passage 25 of the cylinder head 2 to the thermostat housing 1
After flowing into the cooling water inlet passage 12, it flows into the thermostat 4 side in the thermostat fitting chamber 11 facing the cooling water inlet passage 12 via the communication passage 13. In the structure, the cooling water W is supplied from the direction (horizontal direction) perpendicular to the axial direction of the shaft member 43 of the thermostat 4 and from the shaft member 43 located at the center of the thermostat fitting chamber 11. flows toward the axis of
The shaft member 43 acts to bring the shaft member 43 into partial contact with the guide member 42, and as a result, the shaft member 43 wears unevenly and the first valve body 51 and the second valve body 52 are damaged.
As will be described later, the seating performance of the thermostat 4 may deteriorate, and in some cases, the thermostat 4 may become stuck.

However, in this embodiment, by applying the present invention, the shaft member 4 of the thermostat 4 is connected in the communication path 13 and in the cooling water inflow direction.
Since the deflection guide wall 15 extending in the vertical direction is formed at a position that coincides with the axis of the shaft member 43, uneven wear of the shaft member 43 and the occurrence of a sticking phenomenon of the thermostat 4 due to this can be effectively prevented. Ru. That is,
As shown in FIG. 3, this deflection guide wall 15 has a substantially wedge-shaped cross section in the direction of inflow of cooling water.
Therefore, the cooling water W flowing into the thermostat mounting chamber 11 from the cooling water inlet passage 12 is deflected to both sides of the thermostat 4 by the deflection guide wall 15, as shown by the symbols Wa and Wb in FIG. , is guided to the outer periphery of the shaft member 43 of the thermostat 4. Therefore, for example, when the cooling water temperature is close to the valve opening temperature and the first valve element 51 and the second valve element 52 alternately open and close, a large water pressure ( Even if dynamic pressure (dynamic pressure) acts repeatedly on the shaft member 43, the water pressure acts almost uniformly on the entire outer circumferential surface of the shaft member 43, rather than from one side thereof. Therefore, a force that causes uneven wear of the shaft member 43, that is, a force that causes the shaft member 43 to incline to one side, hardly acts, and uneven wear of the shaft member 43 is effectively prevented. This prevents the thermostat 4 from becoming stuck.

Note that this deflection guide wall 15 is connected to the cooling water inlet passage 1.
The shaft member 43 of the thermostat 4 is deflected and guided to the outer periphery of the thermostat 4 by deflecting the cooling water flow flowing into the thermostat mounting chamber 11 side from the 2 side.
This prevents water pressure from acting directly on the part from one side, and prevents the cooling water from flowing into the thermostat fitting chamber 11 side, thereby causing the shaft member 43 of the thermostat 4 to It does not prevent direct water pressure from acting on it, and therefore, the increase in the flow resistance of cooling water due to the deflection guide wall 15 is suppressed as much as possible compared to the latter case, and high-level cooling characteristics are achieved. Can be maintained.

(Effects of the invention) The engine cooling water passage structure of the invention includes a shaft member that is moved forward and backward in the axial direction according to volume changes of the volume variable temperature sensing member, and a shaft member that is attached to the shaft member and that is attached to the shaft member. A thermostat having a valve body that opens and closes as the valve moves forward and backward, and a guide member that slidably supports the shaft member is disposed in the cooling water passage of the engine, and the engine cooling water is directed to the thermostat. In an engine in which the cooling water is caused to flow from a direction perpendicular to the axial direction of the shaft member toward the shaft member, the cooling water is placed at a position upstream of the shaft member of the thermostat and directed in the inflow direction of the cooling water. The present invention is characterized in that a deflection guide wall having a substantially wedge-shaped cross section and acting to deflect and guide the cooling water flow flowing toward the shaft member toward the outer circumferential side of the shaft member is provided.

Therefore, according to the engine cooling water passage structure of the present invention, the cooling water flowing toward the shaft member side of the thermostat is deflected by the deflection guide wall provided on the upstream side of the cooling water from the thermostat. Since the cooling water is guided to the outer circumference side of the shaft member, the dynamic pressure of the cooling water acts almost uniformly on the entire outer circumference of the shaft member, and the shaft member is tilted by the dynamic pressure of the cooling water. It is possible to prevent the shaft member from abutting the guide member unevenly and causing uneven wear, and as a result, a practical effect is obtained in that the thermostat stuck phenomenon is prevented from occurring.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of the essential parts of an engine equipped with a cooling water passage structure according to an embodiment of the present invention, and FIG.
FIG. 3 is a cross-sectional view of FIG. 1. 1... Thermostat housing, 2... Cylinder head, 3... Cooling water pipe, 4... Thermostat, 15... Deflection guide wall, 21, 22... Cooling water passage, 41... Thermostat case, 42...
...Guide member, 43...Shaft member, 51, 52...
Valve body.

Claims (1)

[Scope of utility model registration request] A shaft member that is moved forward and backward in the axial direction in response to changes in the volume of the variable volume temperature sensing member, a valve body that is attached to the shaft member and that is opened and closed as the shaft member moves forward and backward, and the shaft member A thermostat having a guide member that slidably supports the thermostat is disposed in the cooling passage of the engine, and engine cooling water is directed toward the shaft member of the thermostat from a direction perpendicular to the axial direction of the shaft member. In the engine, the cooling water is disposed upstream of the shaft member of the thermostat and has a substantially wedge-shaped cross section in the direction of inflow of the cooling water, and the cooling water flows toward the shaft member side. A cooling water passage structure for an engine, characterized in that a deflection guide wall is provided that acts to deflect and guide water toward the outer circumferential side of the shaft member.