CN1330217A - Cooling device of water-cooled engine - Google Patents

Abstract

A cooling device for a water-cooled engine, in which a wax box is fitted to a casing, and the upper end of the wax box faces a water chamber formed in the casing that communicates with a bypass passage, and can perform expansion and contraction corresponding to the wax. At the same time, when the wax shrinks, the water chamber communicates with the upper passage of the ascending passage; on the housing, there is a lower passage that is blocked by the wax box when the wax shrinks, and is connected to the ascending passage. Partially connected inlet holes and outlet holes connected to the upper passage part of the ascending passage; between the inlet holes and the water chamber, they are connected to each other through the air removal passage. In an engine cooling device with a thermostat that can switch the cooling water flow path according to the temperature of the cooling water in the middle of the ascending path that allows the cooling water to flow, it avoids parts without using air removal bolts, etc. While increasing the number, the air removal performance of the ascending passage is improved.

Description

Cooling device for water-cooled engine

The present invention relates to a cooling device for a water-cooled engine, and in particular to a constant-temperature cooling device which can switch the flow path of the cooling water according to the temperature of the cooling water in the middle of the ascending passage that allows the cooling water to flow upward. engine cooling device.

Conventionally, such a cooling device has been reported in, for example, Japanese Unexamined Patent Application Publication No. 4-75129. On the device: in the lower part of the housing with the thermostat, there is an inlet hole that communicates with the lower side passage in the ascending passage; on the middle part of the housing, there is an inlet hole that communicates with the upper side passage in the ascending passage. A partially connected outlet hole; a bypass hole connected to the bypass passage is provided on the upper part of the above-mentioned casing; the wax box is accommodated in the casing, and the bypass hole can be connected to the outlet hole when the wax is shrinking Sliding between a lower position where the wax is open and an upper position where the inlet hole communicates with the outlet hole when the wax is unexpanded.

Then, when injecting cooling water on the cooling device, the removal of air on the main circulation loop and the secondary circulation loop must be taken into account. However, in the cooling device using the above-mentioned conventional thermostat, there is a height difference between the inlet hole and the outlet hole on the thermostat located in the middle of the ascending passage, which makes the cooling water passage in the thermostat meander. shape. Therefore, for example, in order to be mounted on a two-wheeled motorcycle, the cooling device has to be compactly configured in the vertical direction, since the inclination angle of the ascending passage must be made a small angle, it takes a lot of money to remove the air. To avoid this situation, it is necessary to install parts such as air removal bolts on the ascending passage.

The present invention is proposed in view of such a problem, and its purpose is to provide a cooling device for a water-cooled engine configured in this way: a thermostat is provided in the way of the ascending path that causes the cooling water to rise upward; Eliminate parts such as bolts, avoid an increase in the number of parts, and improve air removal performance for the ascending passage.

To achieve the above objects, the invention described in claim 1 of the present invention relates to a cooling device for a water-cooled engine having a main circulation circuit, a sub circulation circuit, and a thermostat. Wherein, the main circulation loop connects the water cooling jacket of the engine body, the radiator, the water pump, and the above-mentioned water cooling jacket in sequence, and the ascending passage that can make the cooling water circulate upwards constitutes its partial passage; the secondary circulation loop consists of The bypass passage that detours the above-mentioned radiator and a part of the above-mentioned main circulation circuit; and the thermostat is arranged in the middle of the above-mentioned ascending passage, and can block the above-mentioned ascending passage according to the temperature of the cooling water. Switching is made between a state in which the cooling water is circulated and circulated in the sub-circulation circuit and a state in which the bypass passage is blocked and the cooling water is circulated and circulated in the main circulation circuit. The cooling device of the water-cooled engine having the above-mentioned structure is characterized in that it has the following structure: the above-mentioned thermostat has components such as a casing, a wax box, and wax, wherein the casing has a cross-cutting part of the above-mentioned ascending passage. Along the sliding hole extending up and down, the wax box is slidably fitted in the above sliding hole, and its upper end faces the water chamber formed in the housing which communicates with the above bypass passage, and the wax is built in In the wax box, the wax box can slide according to the expansion and contraction caused by the temperature change of the cooling water; the wax box is accommodated in the sliding hole, and the water chamber can be made It communicates with the upper side passage part of the ascending passage; on the above-mentioned housing, an inlet hole and an outlet hole opening to the inner surface of the above-mentioned sliding hole are provided, wherein the inlet hole communicates with the lower side passage part of the above-mentioned ascending passage , the outlet hole communicates with the upper side passage part in the above-mentioned ascending passage, and when the above-mentioned wax shrinks, the entrance and exit holes are blocked by the above-mentioned wax box; further, between the above-mentioned entrance hole and the water chamber, through the pair The air removal passages through which the air in the cooling water is guided are connected to each other.

According to the invention described in claim 1 of the present invention described above, on the housing of the thermostat, the inlet hole and the outlet hole opened toward the inner surface of the sliding hole for causing the wax box to slide are blocked from each other by the wax box when the wax shrinks. and the inlet hole communicates with the passage portion on the lower side of the ascending passage, and the outlet hole communicates with the passage portion on the upper side of the ascending passage. As a result, no level difference can be generated in the ascending passage on the part sandwiching the thermostat; even if the cooling device has to be compactly configured in the up and down direction, it is not necessary to make the inclination angle of the ascending passage as in the existing That is set at a small angle; the air can be quickly circulated in the ascending passage. Furthermore, since the inlet hole communicates with the bypass passage through the air removal passage, the water chamber formed in the upper part of the casing communicates. Therefore, the air in the passage portion on the lower side in the ascending passage can be quickly discharged to the bypass side, improving the air removal performance.

The invention according to claim 2 of the present invention is characterized in that, on the basis of the above-mentioned claim 1, the thermostat is accommodated in a storage box fitted with the housing; The above-mentioned air removal passage is formed on the outside of the housing. Therefore, according to such a configuration, the air removal passage is formed detouring the radiator, thereby further improving the air removal performance.

The invention according to claim 3 of the present invention is characterized in that, in the invention according to claim 1 or 2, the radiator, the water pump, and the thermostat are mounted on the engine body at substantially the same height. . Therefore, according to such a configuration, the cooling device can be compactly assembled on the engine body in the vertical direction.

Fig. 1 is an overall side view of a moped-type two-wheeled vehicle.

Fig. 2 is an enlarged sectional view along line 2-2 of Fig. 1 .

FIG. 3 is an enlarged view of an essential part of FIG. 2 .

Fig. 4 is a sectional view along line 4-4 of Fig. 2 .

Fig. 5 is a diagram of the power unit seen from the arrow direction of line 5-5 in Fig. 1 .

Fig. 6 is an enlarged cross-sectional view along line 6-6 of Fig. 2 .

Fig. 7 is a longitudinal sectional view of the thermostat in a low temperature state.

Fig. 8 is a longitudinal sectional view of the thermostat in a high temperature state.

Fig. 9 is a sectional view along line 9-9 of Fig. 7 .

Fig. 10 is a side view corresponding to Fig. 6 of the second embodiment.

Fig. 11 is a longitudinal sectional view of the thermostat in a low temperature state.

Fig. 12 is a longitudinal sectional view of the thermostat in a high temperature state.

Hereinafter, embodiments of the present invention will be described based on examples of the present invention shown in the accompanying drawings.

1 to 9 show a first embodiment of the present invention. Fig. 1 is an overall side view of a moped-type two-wheeled vehicle. Fig. 2 is an enlarged sectional view along line 2-2 of Fig. 1 . FIG. 3 is an enlarged view of an essential part of FIG. 2 . Fig. 4 is a sectional view along line 4-4 of Fig. 2 . Fig. 5 is a diagram of the power unit seen from the arrow direction of line 5-5 in Fig. 1 . Fig. 6 is an enlarged cross-sectional view along line 6-6 of Fig. 2 . Fig. 7 is a longitudinal sectional view of the thermostat in a low temperature state. Fig. 8 is a longitudinal sectional view of the thermostat in a high temperature state. Fig. 9 is a sectional view along line 9-9 of Fig. 7 .

First, in FIG. 1 , the frame of a moped-type automatic two-wheeled vehicle V having a front wheel Wf steered by a handle 11 and a rear wheel Wr driven by a swinging power unit P is divided into two parts: 3 parts: front frame 12, center frame 13, and rear frame 14. The front frame 12 is composed of an aluminum alloy cast product integrally having a head pipe 12a, a down pipe 12b, and a pedal surface support portion 12c. The center frame 13 supporting the power unit P which can freely swing up and down via the pivot shaft 15 is made of cast aluminum alloy and is joined to the rear end of the front frame 12 . The rear frame 14 extending rearward and upward of the power unit P is formed of an annular pipe member, and supports a fuel tank 16 thereon. A cabinet 17 is supported on the center frame 13 . The casing 17 and the fuel tank 16 are covered by a cover 19 integrally provided with a seat 18 so as to be freely openable and closable.

A power unit P is formed by integrally combining a water-cooled single-cylinder 4-stroke engine E whose cylinders are arranged toward the front of the vehicle body, and a belt-type continuously variable transmission T extending from the left side of the engine E toward the rear of the vehicle body. The rear upper surface of the belt-type continuously variable transmission T is coupled to the rear end of the center frame 13 via a rear shock absorber 20 . The air filter 21 is supported above the belt-type continuously variable transmission T; the muffler 22 is supported on the right side of the belt-type continuously variable transmission T; the main bracket 23 that can stand up and fall down is supported under the engine E .

In FIGS. 2 to 4 , the engine body 24 of the engine E has first and second engine parts 27 and 28 divided by an opening and closing surface 26 extending vertically along the crankshaft 25 . The first engine part 27 constitutes the cylinder block 27a and the crankcase half 27b; the second engine part 28 constitutes the other half of the crankcase. A cylinder head 29 constituting the engine body 24 together with the first and second engine parts 27 and 28 is joined to the front end of the first engine part 27 . A cylinder head cover 30 is joined to the front end of the cylinder head 29 . A generator cover 31 is joined to the right side surfaces of the first and second engine parts 27 and 28 .

The belt-type continuously variable transmission T has a right side cover portion 32 and a left side cover portion 33 coupled to each other. The front right side surface of the right side cover part 32 is joined to the left side surfaces of the first and second engine parts 27 and 28 . Further, a speed reducer cover 34 is coupled to the rear right side surface of the right side cover portion 32 .

A piston 36 slidably fitted in a cylinder 35 having the first engine part 27 is connected to the crankshaft 25 via a connecting rod 37 . A freely rotatable camshaft 38 is supported on the cylinder head 29 . An intake valve and an exhaust valve (not shown) provided on the cylinder head 29 are driven by the camshaft 38 to open and close. A timing chain 40 is housed in a chain passage 39 provided in the first engine unit 27 . The timing chain 40 is wound around a drive sprocket 41 provided on the crankshaft 25 and a driven sprocket 42 provided on the camshaft 38 . Thus, when the crankshaft 25 makes two revolutions, the camshaft 38 makes one revolution.

A driving pulley 43 is provided at the left end of the crankshaft 25 protruding into the inside of the right side cover portion 32 and the left side cover portion 33 . The driving pulley 43 has a fixed-side pulley half 44 fixed to the crankshaft 25 and a movable-side pulley half 45 capable of approaching and separating relative to the fixed-side pulley 44 . The movable side pulley half 45 is subjected to potential energy in a direction approaching the fixed side pulley half 44 by the centrifugal weight 46 that moves radially outward as the number of rotations of the crankshaft 25 increases.

The driven pulley 48 provided on the output shaft 47 supported between the rear portion of the right side cover portion 32 and the reducer cover 34 has a fixed side pulley half 49 and a movable side pulley half 50, wherein the fixed side The pulley half body 49 is supported by the output shaft 47 so as to be relatively rotatable, and the movable side pulley half body 50 is capable of approaching and separating from the fixed side pulley half body 49 . The movable-side pulley half 50 receives potential energy from the spring 51 to the fixed-side pulley half 49 . Further, between the fixed-side pulley half body 49 and the output shaft 47, there is provided a centrifugal coupling 52 that is in a power transmission state when the engine rotation speed exceeds a set rotation speed. Furthermore, a seamless V-belt 53 is wound between the driving pulley 43 and the driven pulley 48 .

Between the right side cover portion 32 and the reducer cover 34 , an intermediate shaft 54 and an axle 55 parallel to the output shaft 47 are supported. A reduction gear set 56 is provided between the output shaft 47 , the intermediate shaft 54 , and the axle 55 . Further, at the right end of the axle shaft 55 protruding from the right side after penetrating the speed reducer cover 34, a rear wheel Wr is provided as a drive wheel.

Then, the rotational power of the crankshaft 25 is transmitted to the drive pulley 43, and then from the drive pulley 43 to the rear wheel Wr via the V-belt 53, the driven pulley 48, the centrifugal linkage 52, and the reduction gear set 56.

The alternator 57 provided on the right side of the crankshaft 25 is covered by the generator cover 31 . A radiator 58 is provided on the right side of the generator housing 31 . A cooling fan 59 fixed to the right end of the crankshaft 25 is arranged between the alternator 57 and the radiator 58 to supply cooling air to the radiator 58 . Therefore, the heat release capacity of the radiator 58 is always larger than the heat output of the engine E.

The cooling fan 59 and the radiator 58 are covered with a synthetic resin cover 60 connected to the generator cover 31 . A louver 61 for introducing air from the outside is provided on the outer surface of the cover 60 .

A water jacket 62 is provided on the cylinder block 27 a and the cylinder head 29 of the first engine unit 27 . A water pump 63 for supplying cooling water to the lower portion of the water jacket 62 on the cylinder block 27 a side is connected to the right end of the camshaft 38 so that its height position is substantially the same as that of the radiator 58 .

A housing box 65 is coupled to the right side of the cylinder head 29 . The thermostat 64A is housed in the storage box 65 . The above-mentioned water pump 63 is housed in a space surrounded by the cylinder head 29 and the housing box 65 . That is, the radiator 58 , the water pump 63 , and the thermostat 64A are mounted on the engine body 24 at substantially the same height.

Referring to FIG. 5 at the same time, one end of the cooling water pipeline 68 is connected to the cylinder head 29 in such a manner as to communicate with the upper portion of the water cooling jacket 62 . The other end of the cooling water line 68 is connected to a closable nozzle 70 that can open and close the upper end opening by a protective cap 71 . The nozzle 70 is connected to the rear fender 66 attached to the power unit P and covering the rear wheel Wf from above so as to swing together with the radiator 58 . Moreover, the nozzle 70 is connected to the water supply port 58a provided in the rear upper part of the radiator 58 via the flexible water supply line 69, such as a rubber hose.

The nozzle 70 is provided with an overflow pipe 70a for overflowing the cooling water. The overflow pipe 70a is connected to a water storage tank not shown in the figure. Between the outlet port 58b provided at the lower front portion of the radiator 58 and the housing box 65, a cooling water line 72 is connected. The cooling water line 72 is connected to the suction port of the water pump 63 via the thermostat 64A in the housing box 65 . Moreover, the storage box 65 and the water cooling jacket 62 in the first engine part 27 are connected by a cooling water line 73 .

That is, the above-mentioned water cooling jacket 62, the radiator 58, and the water pump 63 are connected to each other through the cooling water pipeline 68, the nozzle 70, the water supply passage 69, and the cooling water pipelines 72, 73 to form a main circulation circuit 75. In the main circulation circuit 75 , the cooling water discharged from the water pump 63 passes through the water cooling jacket 62 and the radiator 58 and returns to the water pump 63 , so that the cooling water is circulated and circulated.

In Fig. 6, on the above-mentioned main circulation circuit 75, between the outlet port 58b of the front lower part of the radiator 58 and the suction port of the water pump 63, the above-mentioned suction port from the above-mentioned outlet port 58b below to the top will cool the air. The ascending passages 76 through which water flows upward are connected to each other. The ascending passage 76 is composed of a lower passage portion 77 and an upper passage portion 78 . Wherein, the lower side passage part 77 is formed by the cooling water pipeline 72 and the passage part communicated with the cooling water pipeline 72 provided in the storage box 65; and the upper side passage part 78 is arranged in the storage box 65 and It communicates with the suction port of the water pump 63 . The thermostat 64A is accommodated in the storage box 65 so as to be interposed between the two passage portions 77 and 78 .

At a position adjacent to the cooling water line 68 , one end of the bypass line 79 that detours around the radiator 58 and communicates with the upper portion of the water jacket 62 is connected to the cylinder head 29 . The other end of the bypass line 79 is connected to a cover member 80 connected to the upper portion of the storage box 65 . Then, the bypass line 79 can communicate with the above-mentioned upper passage portion 78 through which the suction port of the water pump 63 communicates via the thermostat 64A in the storage box 65 . In the above-mentioned main circulation circuit 75, the section between the water pump 63 and the water cooling jacket 62, the section between the thermostat 64A and the water pump 63, and the bypass line 74 are formed between the above-mentioned cover member 80 and the cylinder. The bypass passage 81 between the covers 34 constitutes a secondary circulation circuit 82 .

The thermostat 64A can switch between the following two states according to the temperature of the cooling water: the bypass passage 81 is opened while the ascending passage is blocked, so that the cooling water is circulated and circulated in the secondary circulation circuit 82; While ascending the passage 76, the bypass passage 81 is blocked, so that the cooling water flows and circulates in the main circulation circuit 75. Therefore, the thermostat 64A is provided between the lower side passage portion 77 and the upper side passage portion 78 of the ascending passage 76 . Which of the main circulation circuit 75 and the sub-circulation circuit 82 to circulate and circulate the cooling water can be switched according to the temperature of the cooling water.

Referring to FIGS. 7 and 8 at the same time, the thermostat 64A has the following configuration: it has a bottom side passage part and an upper side passage part 77 , 78 extending up and down in a manner that crosses the ascending passage 76 of the main circulation circuit 75 . , and its lower end is a bottomed cylindrical housing 86A with a closed bottomed sliding hole 85; a wax box 87 that can be slidably fitted in the above-mentioned sliding hole 85; compression is arranged on the housing 86A and the wax box The spring 88 between 87; and the wax 89 built in the wax box 87 that can make the above-mentioned wax box 87 slide in response to the expansion and contraction caused by the temperature change of the cooling water.

The wax box 87 is slidably fitted in the slide hole 85 so that the upper end thereof faces the water chamber 90 formed in the housing 86A, which communicates with the bypass passage 81 .

The housing 86A is fitted into a bottomed mounting hole 91 provided in the storage box 65 . By closing the opening end of the mounting hole 91 with the cover member 80 , the housing 86A is housed and fixed in the storage box 65 so as to be pinched between the closed end of the mounting hole 91 and the cover member 80 .

A bottomed cylindrical seal member 92 made of an elastic material that covers one end of the case 86A is attached to one end of the case 86A. One end of the housing 86A is exposed in the form of a tip reinforcement 84 at the center of the inner surface of the closed end of the sealing member 92 . Also, the upper end of the opened case 86A is in contact with the cover member 80 , and a brake wheel 93 is attached to the inner surface of the upper end side of the case 80A.

The wax box 87 is composed of a box main body 94 whose outer surface comes into direct contact with the inner surface of the housing 86A, and a cover 95 bonded to the box main body 94 . The peripheral portion of the diaphragm 96 is sandwiched between the case main body 94 and the cover 95 . Further, a cylindrical guide cylinder 97 , which is slidably fitted in the sealing member 92 , is integrally connected to the case main body 94 .

Wax 89 filled between the above-mentioned diaphragm 96 and cover 95 is contained in the wax box 87 . Diaphragm 96 deforms in response to expansion and contraction of wax 89 due to temperature changes. On the other hand, a rod-shaped piston 98 , a disc-shaped plate 99 , and a rubber piston 100 are sequentially fitted in the guide tube 97 from the opposite side to the diaphragm 96 . The wax box 87 located between the rubber piston 100 and the diaphragm 96 is filled with a medium 101 for transmitting the deformation of the diaphragm 96 to the above-mentioned rubber piston 100 .

Furthermore, between the wax box 87 and the brake roller 93, a spring 88 is provided for making the wax box 87 receive potential energy toward the sealing member 92 side. When the temperature of the cooling water is low and the wax 89 is in a contracted state, the wax box 87 is at a position in contact with the sealing member 92 as shown in FIG. 7 . Then when the temperature of the cooling water rises and the wax 89 expands, the diaphragm 96 is deformed in the form of bending to the lower side of FIG. While compressing the spring 88 , as shown in FIG. 8 , it slides upward on the side away from the sealing member 92 .

On the housing 86A, an inlet hole 102 , an outlet hole 103 , and a bypass hole 104 are provided. Wherein, the inlet hole 102 communicates with the lower side passage part 77 in the ascending passage of the main circulation circuit 75; the outlet hole 103 communicates with the upper side passage part 78 in the above-mentioned ascending passage 76; the inlet hole 102 and the outlet hole 103 are in On the same diameter line as the above-mentioned sliding hole 85, it is provided in the form of opening to the inner surface of the sliding hole 85; the bypass hole 104 allows the above-mentioned water chamber 90 to communicate with the upper side passage part 78, and connects to the above-mentioned outlet. The upper sides of the holes 103 are provided so as to be adjacent to each other.

The above-mentioned inlet hole 102 and outlet hole 103 are provided on the housing 86A in the form of opening toward the inner surface of the above-mentioned slide hole 85 at the following position: when the above-mentioned wax 89 is contracted, as shown in FIG. The space is blocked by the wax box 87; and when the wax 89 is inflated, due to the sliding of the wax box 87, as shown in Figure 8, the inlet and outlet holes are communicated. Also, the bypass hole 104 is provided on the housing 86A at the following position: when the wax 89 is contracted, the bypass hole 104 communicates the water chamber 90 with the upper side passage portion 78; When the sliding of the wax box 87 caused by the expansion of 89 opens the inlet hole 102 and the outlet hole 103, as shown in FIG. 8, the bypass hole 104 is blocked by the wax box 87.

The water chamber 90 and the inlet hole 102 communicate with each other through an air removal passage 105 for guiding air in the cooling water. The air exhaust passage 105 is formed by the groove 106 provided on the inner surface of the mounting hole 91 of the storage box 65 and the outer surface of the casing 86A having the thermostat 64A.

Next, the operation of this first embodiment will be described. The housing 86A of the thermostat 64A is provided with an inlet hole 102 and an outlet hole 103 arranged on the same diameter line as the sliding hole 85 for sliding the wax cartridge 87 . Since the inlet hole 102 communicates with the lower side passage portion 77 of the ascending passage 76 as the passage position of the main circulation circuit 75, and the outlet hole 103 communicates with the upper side passage portion 78 of the ascending passage 76, the thermostat 64A is clamped. In some parts, there may be no level difference on the ascending path 76 . Therefore, even if the cooling device has to be compactly configured in the vertical direction, it is not necessary to set the inclination angle of the ascending passage 76 to a small angle as in the past, but it is possible to make the air flow rapidly in the ascending passage 76. In order to effectively generate circulation, the inclination angle of the ascending passage 76 is set to a relatively large value.

Furthermore, since the inlet hole 102 is communicated with the inlet hole 102 through the air extraction passage 105 in the water chamber 90 formed in the upper part of the housing 86A constituting a part of the bypass passage 81, it is possible to place the water chamber 90 in the ascending passage 76 The air in the lower side passage portion 77 is quickly discharged onto the side of the bypass passage 81 .

As a result, although the thermostat 64A is provided in the middle of the ascending passage 76 through which the cooling water flows upward, it is also possible to increase the flow rate from the ascending passage 76 while avoiding an increase in the number of components without installing an air exhaust bolt or the like. Air removal performance.

Moreover, since the casing 86A of the thermostat 64A is accommodated in the storage box 65, and the above-mentioned air removal passage 105 is formed by the groove 106 on the inner surface of the storage box 65 and the outside of the casing 86A, it is detoured. The air exhaust hole 105 is formed in the same manner as the thermostat 64A. Thereby, the air removal performance can be further improved.

Further, since the radiator 58, the water pump 63, and the thermostat 64A are mounted on the engine body 24 at approximately the same height, the cooling devices can be compactly mounted on the engine body 24 in the vertical direction. As shown in this embodiment, on the engine body 24 of the engine E that constitutes the power unit P together with the continuously variable transmission T and is supported on the vehicle frame F in a swingable manner, the above-mentioned cooling device is compactly arranged in the vertical direction. Collective installation can reduce the required swing space and facilitate loading on the frame F.

10 to 12 show a second embodiment of the present invention. Fig. 10 is a side view corresponding to Fig. 6 in the first embodiment. Fig. 11 is a longitudinal sectional view of the thermostat in a low temperature state. Fig. 12 is a longitudinal sectional view of the thermostat in a high temperature state. The same reference numerals are used for parts corresponding to those of the above-mentioned first embodiment.

The thermostat 64B is provided between the lower side passage portion 77 and the upper side passage portion 78 of the ascending passage 76 which is a part of the passage of the main circulation circuit 75, and makes the cooling water flow between the main circulation circuit 75 and the main circulation circuit 75 according to the temperature of the cooling water. Which side of the sub-circulation circuit 82 produces flow and circulation is switched.

The housing 86B of the thermostat 64A may be formed integrally with the cylinder head 29 of the engine body 24 or may be a member connected to the cylinder head 29 . A sliding hole 85 whose lower end is closed and extends up and down is provided in the housing 86B; the upper end of the housing 86B is closed by a cover member 80'.

A slidable wax box 87 is fitted in the sliding hole 85 ; a spring 88 is compressed between the cover member 80 and the wax box 87 .

The wax box 87 is slidably fitted in the above-mentioned sliding hole 85 with its upper end facing the water chamber 90 communicated with the bypass passage 81 and formed in the casing 86B, and can correspond to the built-in The expansion and contraction of the wax 89 produces a sliding action.

The wax box 87 is composed of a box main body 94 whose outer surface is brought into direct contact with the inner surface of the housing 86B, and a cover 95 bonded to the box main body 94 . Between the box main body 94 and the cover 95 , the peripheral portion of the diaphragm 96 is pinched, and the space between the diaphragm 96 and the cover 95 is filled with wax 89 . Further, a cylindrical guide cylinder 97 is integrally provided with the cartridge main body 94 . A piston 98 , a plate 99 , and a rubber piston 100 are slidably fitted in the guide cylinder 97 . Between the rubber piston 100 and the diaphragm 96, a medium 101 is filled in the wax box 87.

In the housing 86B, an inlet hole 102' and an outlet hole 103' are provided on the same diameter line as the slide hole 85 so as to open to the inner surface of the slide hole 85. As shown in FIG. Wherein, the inlet hole 102' communicates with the lower side passage part 77 in the ascending passage 76 of the main circulation circuit 75;

The inlet hole 102' is formed in a tapered shape whose diameter becomes smaller as it approaches the inner surface of the slide hole 85. As shown in FIG. In addition, the outlet hole 103' is formed in the housing 86B so that the part that cannot be blocked by the wax box 87 is located at the upper part when the wax 89 shrinks. The upper portion of the outlet hole 103' functions as a bypass hole 04' for communicating the water chamber 90 with the upper passage portion 78 when the temperature of the cooling water is low.

Furthermore, between the inlet hole 102' and the water chamber 90, they communicate with each other via an air removal passage 107 for guiding air in the cooling water. The air removal passage 107 is formed in a groove shape at the upper portion of the tapered inlet hole 102' so that the inlet passage 102' communicates with the water chamber 90 when the wax 89 shrinks.

Also in this second embodiment, the same effect as that of the above-mentioned first embodiment can be obtained. In particular, since the wax box 87 is in direct contact with the passage of the cooling system and the engine body 24, it can prevent vibration (Hanchinda) and over-shock (オ-バシュ-ト) phenomenon accompanying the change of cooling water temperature, further Improve cooling performance.

The embodiments of the present invention have been described above. However, the present invention is not limited to the above-mentioned embodiments. Various modifications and designs are possible without departing from the present invention described in the scope of the claims.

As described above, according to the invention described in Claim 1 of the present invention, even if the cooling device has to be configured compactly in the vertical direction, the inclination angle of the ascending passage can be set relatively large, so that the air can be quickly The circulation can be generated efficiently; the air of the lower side passage portion in the ascending passage can be quickly discharged to the side of the bypass passage; and the air removal performance can be improved while avoiding an increase in the number of parts.

According to the invention described in claim 2 of the present invention, since the air removal passage is formed by detouring the thermostat, the air removal performance can be further improved.

Further, according to the invention described in claim 3 of the present invention, the cooling devices can be compactly assembled and installed on the engine body in the vertical direction.

Claims (3)

1. A cooling device for a water-cooled engine, which comprises a main circulation loop (75), a secondary circulation loop (82), and a thermostat (64A, 64B); wherein, the above-mentioned main circulation loop (75) is sequentially connected to the engine body (24) water cooling jacket (62), radiator (58), water pump (63), and above-mentioned water cooling jacket (62), and the ascending passage (76) that can make cooling water circulate upwards as its partial passage; The secondary circulation circuit (82) is made up of a bypass passage (81) detouring the above-mentioned radiator (58) and a part of the above-mentioned main circulation circuit (75); ), according to the temperature of the cooling water, by cutting off the above-mentioned ascending passage (76), it becomes the state that the cooling water circulates and circulates in the above-mentioned secondary circulation circuit (82), and by cutting off the above-mentioned bypass passage (81) , become the state that the cooling water is circulated and circulated in the above-mentioned main circulation circuit (75); it is characterized in that: the above-mentioned thermostat (64A, 64B) has a housing (86A, 86B), a wax box (87), and a wax (89), wherein, the casing (86A, 86B) has a sliding hole (85) extending vertically and vertically across the middle of the above-mentioned ascending passage (76), and the wax box (87) is slidably Fitted in the above-mentioned sliding hole (85), while its upper end face is connected with the above-mentioned bypass passage (81) and formed in the water chamber (90) in the housing (86A, 86B), and the wax (89 ) is built in the wax box (87), and can make the above-mentioned wax box (87) produce sliding action corresponding to the expansion and contraction produced by the temperature change of the cooling water; the above-mentioned wax box (87) is embedded in In the above-mentioned sliding hole (85), the above-mentioned water chamber (90) can be communicated with the upper side passage part (78) of the above-mentioned ascending passage (76) when the above-mentioned wax (89) shrinks; 86B), there are inlet holes (102, 102') and outlet holes (103, 103') opening to the inner surface of the above-mentioned sliding hole (85), wherein the inlet holes (102, 102') are connected to the above-mentioned ascending passage The lower side passage part (77) in (76) is connected, and the outlet hole (103, 103 ') is connected with the upper side passage part (78) in the above-mentioned ascending passage (76), and in the above-mentioned wax (89) When shrinking, the above-mentioned wax boxes (87) are blocked from each other; further, between the above-mentioned inlet holes (102, 102') and the water chamber (90), the air removal passage (105) for guiding the air in the cooling water , 107) and interconnected. 2. The cooling device of a water-cooled engine according to claim 1, characterized in that: the above-mentioned thermostat (64A) is accommodated in a storage box (65) fitted with the above-mentioned housing (86A), and is arranged in the storage box. The groove (106) on the inner surface of (65) and the outer surface of the housing (86A) form the air removal passage (105). 3. The cooling device for a water-cooled engine according to claim 1 or 2, characterized in that: the above-mentioned radiator (58), the above-mentioned water pump (63), and the above-mentioned thermostat (64A, 64B) are arranged at approximately the same height Be installed on the above-mentioned engine body (24).

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