WO2020208763A1

WO2020208763A1 - Water pump device and internal combustion engine comprising same

Info

Publication number: WO2020208763A1
Application number: PCT/JP2019/015729
Authority: WO
Inventors: 宗博嵯峨田; 啓一上浦; 和慶山口
Original assignee: 愛知機械工業株式会社
Priority date: 2019-04-11
Filing date: 2019-04-11
Publication date: 2020-10-15

Abstract

[Problem] To improve the quality of a water pump device. [Solution] When providing an opening 47a as a vapor release hole on a second boss part 46 of a pump housing 22, the second boss part having a point P1 where the distance from an inner circumferential surface of a pump pulley 28 is smallest, the opening 47a is disposed in a region 90 on a front side in the rotational direction of the pump pulley 28 with respect to a virtual straight line VL. Additionally, the opening 47a is disposed at a position closer to the axis centerline of a main boss part 42 than to the axis centerline of a second boss part 46. Due to this configuration, compared to a configuration in which the opening 47a is disposed on a region 91 side on a back side of the rotational direction of the pump pulley 28, it is possible to suppress the generation of air flow from the opening 44b to the opening 47a caused by the rotation of the pump pulley 28. As a result thereof, it is possible to satisfactorily prevent the intrusion of foreign matter and the like from outside into a space section 70, and to improve the quality of the water pump device 20.

Description

Water pump device and internal combustion engine equipped with it

The present invention comprises a drive shaft having a bearing portion, a pulley fixed to the first end portion of the drive shaft in the axial direction so as to be integrally rotatable with the drive shaft, and the drive shaft so as to be integrally rotatable with the drive shaft. A housing having an impeller fixed to a second end portion in the axial direction, a main boss portion that rotatably supports the drive shaft via the bearing portion, an internal space of the main boss portion, and the impeller are arranged. The present invention relates to a water pump device including a seal member arranged between the bearing portion and the impeller so as to partition the region in a liquid-tight manner, and an internal combustion engine including the water pump device.

Japanese Patent Application Laid-Open No. 2007-32406 (Patent Document 1) describes a water pump housing, a drive shaft having a bearing portion and rotatably supported by the water pump housing via the bearing portion, and an axis of the drive shaft. A water pump device comprising an impeller fixed to one end in the direction and a pulley fixed to the other end in the axial direction of the drive shaft is described. In the water pump device, a mechanical seal is arranged between the bearing portion and the impeller in the axial direction of the drive shaft. Further, the water pump housing has a space between the bearing portion and the mechanical seal in a state where the drive shaft is supported, and also has a steam hole and a drain hole for communicating the space with the outside. The drain hole is provided in a reservoir that can store water leaks that have entered the space from the impeller side.

In the water pump device described in the above-mentioned publication, vapor-like water leaks that have entered the space from the impeller side are discharged from the steam holes, and condensed water droplets that have entered the space from the impeller side are discharged. After being temporarily stored in the reservoir, it is vaporized and discharged from the steam hole or pressure relief hole.

JP-A-2007-32406

By the way, the steam holes and drain holes are generally arranged in the boss integrated with the outer peripheral surface of the shaft support boss portion that supports the drive shaft in the water pump housing. At that time, the pulley is arranged in a state of overlapping with the boss in the axial direction thereof, and the boss in which the drain hole is arranged is in the radial direction as compared with the boss in which the steam hole is arranged because it has a reservoir. It may be formed large. As a result, the gap between the outer peripheral surface of the boss on which the drain hole is arranged and the inner peripheral surface of the pulley is the smallest as compared with the gap of other parts, and the pulley rotates across the region where the gap is the smallest. There is a pressure difference before and after the direction. As a result, an air flow from the steam hole to the drain hole may be generated due to the pressure difference, and impurities may be mixed in the water pump housing, and there is still room for improvement in terms of quality improvement. ..

The present invention has been made in view of the above, and one of the objects of the present invention is to provide a technique that contributes to improving the quality of a water pump device.

The water pump device of the present invention and the internal combustion engine provided with the water pump device have adopted the following means in order to achieve the above-mentioned object.

According to a preferred embodiment of the water pump device according to the present invention, a drive shaft having a bearing portion, a pulley fixed to the first end portion of the drive shaft in the axial direction so as to be integrally rotatable with the drive shaft, and a drive shaft. A housing having an impeller fixed to the second end of the drive shaft in the axial direction so as to be rotatable integrally with the drive shaft, a main boss portion that rotatably supports the drive shaft via a bearing portion, and an internal space of the main boss portion. A water pump device including a seal member arranged between the bearing portion and the impeller so as to liquidally partition the area where the impeller is arranged is configured. In the water pump device, the first and second boss portions are integrated on the outer peripheral surface of the main boss portion. Further, the first and second boss portions have a hollow shape having first and second openings. Further, of the internal space of the main boss portion, the first space arranged between the bearing portion and the seal member communicates with the outside through the first opening and the second opening. Further, the pulley covers at least a part of the first and second boss portions so as to include the first and second openings. The first distance, which is the minimum of the radial distance between the inner peripheral surface of the pulley and the first boss portion, is larger than the second distance, which is the minimum of the radial distance between the inner peripheral surface of the pulley and the second boss portion. large. The second opening is a second point that is the starting point of the second distance of the second boss portion in the virtual projection region when the water pump device is viewed from one side in the axial direction of the drive shaft, and the drive in the virtual projection region. The virtual straight line connecting the center of rotation of the shaft and the virtual straight line are arranged in a region on the front side in the rotation direction of the pulley.

Here, as the pulley rotates, an air flow is generated in the space between the inner peripheral surface of the pulley and the outer peripheral surface of the main boss portion including the first and second boss portions, and the inner peripheral surface of the pulley and the first When the air passes through the region where the distance between the outer peripheral surface of the main boss portion including the first and second boss portions is the minimum (second distance), the air is compressed. On the other hand, after passing through the region where the distance between the inner peripheral surface of the pulley and the outer peripheral surface of the main boss portion including the first and second boss portions is the minimum (second distance), the air is released from the compressed state. Will be done. According to the present invention, the front side in the rotation direction of the pulley with respect to the region where the distance between the inner peripheral surface of the pulley and the outer peripheral surface of the main boss portion including the first and second boss portions is the minimum (second distance). That is, since the second opening is arranged in the region where the air is compressed, the distance between the first opening and the second opening is compared with the configuration in which the second opening is arranged in the region where the air is released from the compressed state. It is possible to suppress the differential pressure generated in. As a result, it is possible to suppress the generation of an air flow from the first opening to the second opening through the inside of the housing, and it is possible to satisfactorily suppress the mixing of impurities and the like into the first space of the housing. As a result, the quality of the water pump device can be improved.

According to a further form of the water pump device according to the present invention, the second boss portion has a reservoir portion capable of temporarily storing water leakage from the area where the impeller is arranged to the first space. The first space communicates with the second opening via a reservoir. The second opening is arranged at a position near the center of the drive shaft in the reservoir.

According to this embodiment, since the inside of the second boss portion can be used as a reservoir portion, the device can be made compact. Moreover, since the second opening is arranged at a position closer to the axis center of the drive shaft in the reservoir, that is, above, it is possible to satisfactorily prevent the stored water leakage from leaking from the second opening.

According to a preferred embodiment of the internal combustion engine according to the present invention, a cylinder head, a cylinder block fastened to the cylinder head, a crankshaft rotatably supported by the cylinder block, and any of the above-mentioned attached to the cylinder block. A water pump device according to the present invention of the above aspect, and a belt wound around a crankshaft and a pulley are provided.

According to the present invention, it is possible to satisfactorily suppress an effect similar to the effect exerted by the water pump device according to the present invention in any of the above-described aspects, for example, contamination of impurities or the like in the first space of the housing. It is possible to achieve the effect of improving the quality and the effect of making the device compact.

According to the present invention, the quality of the water pump device can be improved.

It is a schematic block diagram which shows the outline of the structure of the internal combustion engine 1 which concerns on embodiment of this invention. It is a schematic block diagram which shows the outline of the structure of the cylinder block 6. It is sectional drawing which shows the AA cross section of FIG. It is a front view which saw the water pump device 20 from one side in the axial direction of the drive shaft 24. It is an enlarged view of the main part which shows the detail of part D of FIG. 4 enlarged. It is a back view which saw the water pump device 20 from the impeller 30 side. It is explanatory drawing which shows the arrangement of the opening 47a. It is explanatory drawing which shows the state of the negative pressure in the space 92 between the inner peripheral surface of a pump pulley 28, and the outer peripheral surface of the main boss portion 42 including the first and

second boss portions

44, 46.

Next, the best mode for carrying out the present invention will be described with reference to examples.

As shown in FIG. 1, the internal combustion engine 1 according to the embodiment of the present invention includes a cylinder head 2, a rocker cover 4 attached to the upper part of the cylinder head 2, and a cylinder attached to the lower part of the cylinder head 2. The block 6, the upper oil pan 8 attached to the lower part of the cylinder block 6, the lower oil pan 10 attached to the lower part of the upper oil pan 8, and the water pump device 20 attached to the cylinder block 6. Is equipped with.

As shown in FIG. 2, the cylinder block 6 is configured as one of the main components constituting the skeleton of the internal combustion engine 1 that rotatably supports the crankshaft CS, and has a front wall portion 62a and a rear wall portion 62b. A

side wall portion

64a, 64b connected to the front wall portion 62a and the rear wall portion 62b, and a bore wall 66 having a cylinder bore 66a are provided.

As shown in FIG. 2, the

side wall portions

64a and 64b extend along the cylinder bore arrangement direction (left-right direction in FIG. 2). A pump chamber 72 and a suction passage portion 74 connected to the pump chamber 72 are integrally formed on the side wall portion 64a.

A block water jacket BWJ is formed between the front wall portion 62a, the rear wall portion 62b, the

side wall portions

64a, 64b, and the bore wall 66. The block water jacket BWJ is configured as a cooling water passage through which cooling water flows, and the cylinder block 6, particularly around the bore wall 66, is cooled by the cooling water flowing through the block water jacket BWJ.

Further, as shown in FIG. 2, a cooling water introduction passage 69 is provided in a portion of the block water jacket BWJ closest to the front wall portion 62a and adjacent to the pump chamber 72. The cooling water introduction passage 69 is communicated with the discharge port of the pump chamber 72. The discharge port of the pump chamber 72 is arranged in a discharge passage composed of a discharge passage portion 72a of the pump chamber 72 and a discharge passage portion 28a (see FIG. 6) of the pump housing described later.

As shown in FIG. 2, the pump chamber 72 is integrally formed in a portion of the side wall portion 64a that is closer to the front wall portion 62a (front wall portion 62a side end portion). The water pump device 20 is attached to the end surface of the pump chamber 72 facing the front wall portion 62a side.

As shown in FIG. 2, the suction passage portion 74 extends along the cylinder bore arrangement direction (left-right direction in FIG. 2) in the upper portion (upper side in FIG. 2) of the side wall portion 64a. One end of the suction passage 74 is connected to the pump chamber 72, and the other end of the suction passage 74 is connected to the rear wall 62b. A cooling water passage through which cooling water flows is formed inside the suction passage portion 74. One end of the cooling water passage is communicated with a suction port (not shown) formed in the pump chamber 72, and the other end of the cooling water passage is a cooling (not shown) in which the cooling water after cooling the internal combustion engine 1 is returned. It is connected to the water return passage.

The water pump device 20 is configured as a spiral type centrifugal pump that circulates cooling water, and is rotatably supported by the pump housing 22 and the pump housing 22 via a bearing portion 24a as shown in FIG. The drive shaft 24, the flange 26 fixed to one end of the drive shaft 24 in the axial direction, the pump pulley 28 fixed to the flange 26, and the impeller fixed to the other end of the drive shaft 24 in the axial direction. 30 and a mechanical seal 32 attached to the pump housing 22 so as to be in sliding contact with the outer peripheral surface of the drive shaft 24. As shown in FIG. 1, in the water pump device 20, the rotational force of the crankshaft CS is transmitted via the crank pulley CP fixed to the crankshaft CS and the auxiliary belt BELT wound around the pump pulley 28. Driven by. The auxiliary belt BELT is an example of an implementation configuration corresponding to the "belt" in the present invention.

As shown in FIG. 3, the pump housing 22 has a cylindrical main boss portion 42 having a through hole 42a for rotatably supporting the drive shaft 24 via a bearing portion 24a, and an outer circumference of the main boss portion 42. It has first and

second boss portions

44, 46 integrated with the surface. The pump housing 22 is an example of an implementation configuration corresponding to the "housing" in the present invention.

As shown in FIG. 3, the through hole 42a of the main boss portion 42 includes a shaft support portion 43a having an inner diameter substantially the same as the outer diameter of the bearing portion 24a, and a small diameter portion 43b having an inner diameter smaller than that of the shaft support portion 43a. It is configured in a stepped shape with. A mechanical seal 32 is attached to the small diameter portion 43b. By attaching the mechanical seal 32 to the small diameter portion 43b, the through hole 42a is formed with a space portion 70 between the bearing portion 24a and the mechanical seal 32. Further, the main boss portion 42 has

communication passages

42b and 42c that communicate the space portion 70 and the

recesses

44a and 46a of the first and

second boss portions

44 and 46, which will be described later. The space portion 70 is an example of an implementation configuration corresponding to the “internal space” and the “first space” in the present invention.

As shown in FIG. 3, the first boss portion 44 extends along the axial direction of the main boss portion 42, and has a recess 44a opened at one end in the extending direction. The opening 44b of the recess 44a faces the side where the pump pulley 28 is arranged (left side in FIG. 3) when the drive shaft 24 is supported by the shaft support portion 43a via the bearing portion 24a. Further, as shown in FIG. 4, the first boss portion 44 has a substantially semicircular or circular shape when viewed from one side in the extending direction. In other words, it can be said that the first boss portion 44 has a substantially semi-cylindrical or cylindrical shape. The opening 44b is an example of an implementation configuration corresponding to the "first opening" in the present invention.

As shown in FIG. 3, the second boss portion 46 extends along the axial direction of the main boss portion 42, and one end of the extending direction, more specifically, the bearing portion 24a is attached to the shaft support portion 43a. When the drive shaft 24 is supported via the above, the side (left side in FIG. 3) on which the pump pulley 28 is arranged has an open recess 46a. The opening of the recess 46a is closed by a plug plug PLG, and a space 80 is formed. As shown in FIG. 4, the second boss portion 46 has a substantially circular shape when viewed from one side in the extending direction. In other words, it can be said that the second boss portion 46 has a substantially cylindrical shape. The space portion 80 is an example of an implementation configuration corresponding to the “reservoir portion” in the present invention.

Further, as shown in FIGS. 3 and 4, the amount of protrusion of the second boss portion 46 from the main boss portion 42 (the amount of protrusion in the radial direction) is the amount of protrusion of the first boss portion 44 from the main boss portion 42. It is larger than (amount of protrusion in the radial direction). Further, as shown in FIG. 3, the second boss portion 46 has a single groove 47 on the opening end side. The concave groove 47 extends from the space 80 to the opening end of the recess 46a, and has an opening 47a at the opening end. In other words, it can be said that the space portion 80 communicates with the outside by the concave groove 47. The opening 47a is an example of an implementation configuration corresponding to the "second opening" in the present invention.

As shown in FIG. 4, the second boss portion 46 has a phase of about 180 degrees with respect to the main boss portion 42, which is the side opposite to the side where the first boss portion 44 is arranged, that is, the first boss portion 44. Is placed in a misaligned position. The second boss portion 46 is arranged on the lower side in the vertical direction when the internal combustion engine 1 to which the water pump device 20 is attached is mounted on the vehicle.

As shown in FIGS. 3 to 5, the concave groove 47 is arranged at a position closer to the axis center line of the main boss portion 42 than the axis center line of the second boss portion 46. Further, as shown in FIG. 7, the concave groove 47 connects the water pump device 20 to the axis of the drive shaft 24 when the pump pulley 28 is attached to the drive shaft 24 pivotally supported by the pump housing 22 via the flange 26. A point P1 on the second boss portion 46 that minimizes the distance between the inner peripheral surface of the pump pulley 28 and the second boss portion 46 in the virtual projection region when viewed from one side in the direction, and the virtual projection region. With respect to the virtual straight line VL connecting the rotation center RP of the drive shaft 24, it is arranged in the region 90 (the region on the solid line arrow side in FIG. 7) on the front side in the rotation direction of the pump pulley 28 (two-point chain line arrow in FIG. 7). Has been done. The minimum distance d1 between the inner peripheral surface of the pump pulley 28 and the first boss portion 44 in the virtual projection region is the minimum distance between the inner peripheral surface of the pump pulley 28 and the second boss portion 46 in the virtual projection region. It is larger than d2. The minimum distance d1 corresponds to the "first distance" in the present invention, and the minimum distance d2 is an example of an embodiment configuration corresponding to the "second distance" in the present invention. Further, the point P1 is an example of the implementation configuration corresponding to the "second point" in the present invention.

As shown in FIGS. 3, 4, and 8, the pump pulley 28 has a bottomed cylindrical shape in which one side in the axial direction is open and the other side in the axial direction is closed, and the auxiliary belt BELT is provided on the outer peripheral surface. Is wrapped around. The pump pulley 28 is an example of an implementation configuration corresponding to the "pulley" in the present invention.

As shown in FIGS. 3 and 6, the impeller 30 has a plurality of blades 30a and is fixed to the drive shaft 24 so as to be integrally rotatable with the drive shaft 24. As the impeller 30 rotates, cooling water is sucked into the pump chamber 72 from a suction passage (not shown) of the pump chamber 72 (see FIG. 2), and the discharge passage portion 28a (see FIG. 6) of the pump housing 22 and the pump chamber. It is discharged from a discharge port (not shown) including the discharge passage portion 72a (see FIG. 2) of 72.

As shown in FIG. 3, the mechanical seal 32 is arranged between the bearing portion 24a and the impeller 30, and penetrates the area of the pump chamber 72 side, that is, the side where the impeller is arranged, with respect to the mechanical seal 32. The area of the hole 42a on the shaft support portion 43a side, that is, the space portion 70 side is liquid-tightly partitioned. The mechanical seal 32 is an example of an implementation configuration corresponding to the “seal member” in the present invention.

Next, the operation of the water pump device 20 driven by the operation of the internal combustion engine 1 configured in this way will be described. When the operation of the internal combustion engine 1 is started and the crankshaft CS is rotated, the crank pulley CP fixed to the crankshaft CS is rotated. The rotation of the crank pulley CP is transmitted to the pump pulley 28 via the auxiliary belt BELT. The rotation of the pump pulley 28 is transmitted to the drive shaft 24 via the flange 26, and the impeller 30 rotates with the rotation of the drive shaft 24. As a result, the cooling water is sucked from the suction passage portion 74 into the suction port (not shown) of the pump chamber 72, and the sucked cooling water is introduced from the discharge port (not shown) of the pump chamber 72. It is supplied to the block water jacket BWJ via 69.

Here, if the internal combustion engine 1 is continuously operated, the cylinder block 6 becomes hot and the pump chamber 72 also becomes hot. As a result, the cooling water flowing in the pump chamber 72 also becomes hot, and a part of the cooling water becomes vapor-like, and may infiltrate into the space 70 through the gap formed between the mechanical seal 32 and the drive shaft 24. ..

A part of the vapor (vaporized cooling water) that has entered the space 70 flows into the recess 44a of the first boss 44 through the communication passage 42b, and is discharged to the outside through the opening 44b. On the other hand, the remaining portion of the vapor (vaporized cooling water) that has penetrated into the space 70 is condensed into water droplets. The water droplets flow into the space 80 of the second boss 46 via the communication passage 42c and are stored in the space 80. In this way, since the space portion 80 is used as a storage portion for the water-dropped cooling water, the device should be made more compact than a configuration in which a storage portion for storing the water-dropped cooling water is separately provided. Can be done.

Further, since the temperature of the pump housing 22 also rises due to heat transfer from the cylinder block 6 and the pump chamber 72, a part of the cooling water that has become water droplets and stored in the space 80 may become vapor-like again. The vapor is discharged to the outside through a concave groove 47 provided in the concave portion 46a. The space portion 80 is set to a volume capable of sufficiently storing the cooling water that penetrates into the space portion 70 through the gap between the mechanical seal 32 and the drive shaft 24 and becomes water droplets. Further, since the concave groove 47 is arranged at a position closer to the axis center line of the main boss portion 42 (rotation center RP of the drive shaft 24) than the axis center line of the second boss portion 46, it is stored in the space portion 80. It is possible to satisfactorily suppress the leakage of the water-dropped cooling water from the concave groove 47.

The concave groove 47 is arranged in the region 90 (the region on the solid line arrow side in FIG. 7) on the front side in the rotation direction of the pump pulley 28 (the two-dot chain arrow in FIG. 7) with respect to the virtual straight line VL. In other words, as the pump pulley 28 rotates, the space 92 between the inner peripheral surface of the pump pulley 28 and the outer peripheral surface of the main boss portion 42 including the first and

second boss portions

44 and 46. Since the concave groove 47 is arranged in the region 92a where the air is in the compressed state, the region other than the region 92a, that is, the region 92b in the space 92 where the air is released from the compressed state (with respect to the virtual straight line VL, the pump pulley). The opening 44b (FIG. 3) is compared with the configuration in which the concave groove 47 is arranged in the region 91 (the region on the dashed arrow side in FIG. 7) on the rear side of the rotation direction of 28 (the two-dot arrow in FIG. 7). The differential pressure generated between the opening 47a (see FIG. 3) and the opening 47a (see FIG. 3) can be suppressed. Here, the shade of color in FIG. 8 indicates the magnitude of the negative pressure in the space 92, and the darker the color (region 92b), the larger the negative pressure.

As a result, as the pump pulley 28 rotates, the opening 47a (see FIG. 3) is opened from the opening 44b (see FIG. 3) through the recess 44a, the communication passage 42b, the space portion 70, the communication passage 42c, the space portion 80, and the concave groove 47 (FIG. 3). It is possible to suppress the generation of the airflow flowing to (see 3), and it is possible to satisfactorily suppress the mixing of contaminants and the like from the outside into the space 70. As a result, the quality of the water pump device 20 can be improved.

In the present embodiment, the second boss portion 46 has a concave groove 47, but the present invention is not limited to this. For example, the plug plug PLG may be provided with a communication hole for communicating the recess 46a and the outside.

In this embodiment, a single groove 47 is used, but the present invention is not limited to this. The second boss portion 46 may have two or more recessed grooves 47.

The present embodiment shows an example of a mode for carrying out the present invention. Therefore, the present invention is not limited to the configuration of the present embodiment.

1 Internal combustion engine (internal combustion engine)
2 Cylinder head (cylinder head)
4 Rocker cover 6 Cylinder block (cylinder block)
8 Upper oil pan 10 Lower oil pan 20 Water pump device (water pump device)
22 Pump housing (housing)
24 Drive shaft (Drive shaft)
24a Bearing part (bearing part)
26 Flange 28 Pump pulley (pulley)
28a Discharge passage 30 Impeller (impeller)
30a blade 32 mechanical seal (seal member)
42 Main boss part (main boss part)
42a Through hole 42b Continuous passage 42c Continuous passage 43a Shaft support part 43b Small diameter part 44 1st boss part (1st boss part)
44a recess 44b opening (first opening)
46 Second boss part (second boss part)
46a recess 47 concave groove 47a opening (second opening)
62a Front wall part 62b Rear wall part 64a Side wall part 64b Side wall part 66 Bore wall 66a Cylinder bore 69 Cooling water introduction passage 70 Space part (internal space, first space)
72 Pump chamber 72a Discharge passage 74 Suction passage 80 Space (reservoir)
90 area (area)
91 area 92 space 92a area (area)
92b area CS crankshaft (crankshaft)
CP Crank Pulley BWJ Block Water Jacket BELT Auxiliary Belt (Belt)
PLG plug plug RP center of rotation VL virtual straight line d1 minimum distance (first distance)
d2 minimum distance (second distance)
P1 point (2nd point)

Claims

A drive shaft having a bearing portion, a pulley fixed to the first end portion of the drive shaft in the axial direction so as to be integrally rotatable with the drive shaft, and a second in the axial direction of the drive shaft so as to be integrally rotatable with the drive shaft. A housing having an impeller fixed to two ends, a main boss portion that rotatably supports the drive shaft via the bearing portion, an internal space of the main boss portion, and an area where the impeller is arranged. A water pump device including a seal member arranged between the bearing portion and the impeller so as to be liquid-tightly partitioned.
The first and second boss portions are integrated on the outer peripheral surface of the main boss portion.
The first and second boss portions have a hollow shape having first and second openings.
Of the internal space of the main boss portion, the first space arranged between the bearing portion and the seal member communicates with the outside through the first opening and the second opening.
At least a part of the first and second boss portions is covered with the pulley so as to include the first and second openings.
The first distance (d1), which is the minimum of the radial distance between the inner peripheral surface of the pulley and the first boss portion, is the smallest of the radial distance between the inner peripheral surface of the pulley and the second boss portion. Is larger than the second distance (d2)
The second opening includes a second point serving as a starting point of the second distance on the second boss portion in a virtual projection region when the water pump device is viewed from one side in the axial direction of the drive shaft, and the second opening. A water pump device arranged in a region on the front side in the rotation direction of the pulley with respect to a virtual straight line connecting the rotation center of the drive shaft in the virtual projection region.
The second boss portion has a reservoir portion capable of temporarily storing water leakage from the area where the impeller is arranged to the first space.
The first space communicates with the second opening via the reservoir.
The water pump device according to claim 1, wherein the second opening is arranged at a position closer to the axis center of the drive shaft in the reservoir.
With the cylinder head
A cylinder block fastened to the cylinder head and
A crankshaft rotatably supported by the cylinder block,
The water pump device according to claim 1 or 2, which is attached to the cylinder block.
A belt wound around the crankshaft and the pulley,
Internal combustion engine equipped with.