water pump

Abstract

A technology is provided to extend the life of a water pump. A water pump (10) has a support portion (40) with a bearing hole (41) and a bottomed cylindrical pulley (60) disposed at one end (51) of a rotating shaft (50). The support portion (40) has an annular small-diameter portion (42) with a bearing hole (41) formed at its center, and an annular large-diameter portion (45). At least a portion of the small-diameter portion (42) is located on the pulley (60) side closer to the large-diameter portion (44). An annular first gap (C1) is formed between the cylindrical portion (62) and the large-diameter portion (45) of the pulley (60). A second cylindrical portion (67) is disposed at the bottom (61) of the pulley (60). An annular second gap (C2) is formed between the second cylindrical portion (67) and the small-diameter portion (42).

Description

Technical Field

[0001] This invention relates to a water pump driven by a pulley. Background Technology

[0002] Cooling water used to cool the engine is circulated by a water pump. As prior art regarding water pumps, there is a technology disclosed in Patent Document 1.

[0003] Patent Document 1 discloses a water pump comprising: a support portion having a bearing chamber for supporting a bearing formed in the horizontal direction; an impeller drive shaft supported by the bearing and capable of rotation, extending through the bearing chamber; a pulley disposed at one end of the impeller drive shaft and driven by a belt; an impeller disposed at the other end of the impeller drive shaft; and a mechanical seal disposed between the impeller and the bearing. When the pulley is driven by the belt, the impeller disposed on the impeller drive shaft rotates, and cooling water is delivered.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Utility Model Application Publication No. 3-65891 Summary of the Invention

[0007] The problem the invention aims to solve

[0008] The pulley is cylindrical with a bottom, surrounding an annular support. An annular gap is formed between the outer circumferential surface of the support and the inner circumferential surface of the pulley's cylindrical portion.

[0009] In the operating environment of a water pump, dust, dirt, mud, sand, water, and oil (hereinafter referred to as dust) can sometimes seep into the annular gap formed between the pulley and the support. If the dust penetrates and reaches the inside of the bearing, the bearing's lifespan will be shortened.

[0010] A circular plate-shaped partition is provided on the outer circumference of the support. By providing the partition, the gap between the pulley and the support is narrowed, which can prevent dust from entering the interior of the pulley.

[0011] The partition plate is fixed to the outer circumferential surface of the support by pressing or riveting. As mentioned above, the support is the part that supports the bearing. If external force is applied to the support during the pressing or riveting of the partition plate, it may put a load on the bearing and cause a decrease in bearing life.

[0012] The present invention aims to provide a technology that extends the lifespan of water pumps.

[0013] Solution for solving the problem

[0014] According to the invention of claim 1, a water pump is provided, comprising: a support portion having a bearing hole for supporting a bearing; a rotating shaft supported by the bearing and rotatable, and extending through the bearing hole; a bottomed cylindrical pulley disposed at one end of the rotating shaft; an impeller disposed at the other end of the rotating shaft; and a sealing member disposed between the impeller and the bearing.

[0015] The support portion has a communication hole that connects the sealing member in the bearing hole with the space in front of the bearing and the outside of the support portion.

[0016] The aforementioned water pump is characterized in that,

[0017] The aforementioned support portion has: an annular small-diameter portion with the aforementioned bearing hole formed at its center; and an annular large-diameter portion, the diameter of the outer peripheral surface of which, centered on the aforementioned bearing hole, is larger than the diameter of the outer peripheral surface of the aforementioned small-diameter portion.

[0018] At least a portion of the aforementioned smaller diameter portion is located on the pulley side closer to the larger diameter portion.

[0019] An annular first gap is formed between the cylindrical portion of the pulley and the large-diameter portion.

[0020] A second cylindrical section is provided at the bottom of the pulley, and an annular second gap is formed between the second cylindrical section and the small diameter section.

[0021] As described in Solution 2, preferably, the axial dimension of the overlap between the cylindrical portion of the pulley and the large-diameter portion of the support portion is taken as the first dimension.

[0022] Taking the axial dimension of the overlap between the second cylindrical portion and the small-diameter portion of the support portion as the second dimension, then

[0023] The first dimension mentioned above is shorter than the second dimension mentioned above.

[0024] As described in Solution 3, the radial dimension of at least one of the first gap and the second gap is set to narrow as it extends toward the impeller side, based on the direction extending from the centerline of the bearing hole.

[0025] As described in Solution 4, the support portion has a facing surface opposite to the bottom of the pulley, and in addition to the connecting hole, a recess is formed on the facing surface.

[0026] As described in Solution 5, the larger diameter portion surrounds the smaller diameter portion. With the radial direction as a reference, the thickness of the larger diameter portion is thinner than the thickness of the smaller diameter portion, and the recess is formed by utilizing the space between the smaller diameter portion and the larger diameter portion.

[0027] As described in Solution 6, multiple ribs are formed from the outer peripheral surface of the small diameter portion to the inner peripheral surface of the large diameter portion.

[0028] As described in Solution 7, the centerline of the bearing hole extends in the horizontal direction, and at least a portion of the recess formed on the opposite surface is located above the upper end of the bearing.

[0029] Invention Effects

[0030] In Scheme 1, the water pump has: a support portion that supports a rotating shaft; and a bottomed cylindrical pulley disposed at one end of the rotating shaft. The support portion has: an annular small-diameter portion with a bearing hole formed at its center; and an annular large-diameter portion whose outer circumferential diameter is larger than the outer circumferential diameter of the small-diameter portion.

[0031] At least a portion of the smaller diameter section is located closer to the pulley than the larger diameter section. A first annular gap is formed between the pulley's cylindrical portion and the larger diameter section. A second cylindrical portion is provided at the bottom of the pulley. A second annular gap is formed between this second cylindrical portion and the smaller diameter section.

[0032] That is, two gaps are formed between the pulley and the support to prevent dust from entering. Therefore, dust does not easily reach the inside of the bearing.

[0033] Furthermore, the second cylindrical section is located at the bottom of the pulley. Since the second cylindrical section is not fitted into the support section, no external force is applied to the support section. As a result, no load is applied to the bearing located in the support section. Therefore, a longer bearing life can be achieved.

[0034] Furthermore, the second cylindrical section is provided on the pulley, which is a rotating body. When the pulley rotates, the second cylindrical section also rotates. Airflow is facilitated in the second gap between the second cylindrical section and the small-diameter portion of the support. Dust does not easily penetrate into the second gap.

[0035] In Scheme 2, the axial dimension of the overlap between the cylindrical portion of the pulley and the large-diameter portion of the support is defined as the first dimension. The axial dimension of the overlap between the second cylindrical portion and the small-diameter portion of the pulley is defined as the second dimension. The first dimension is shorter than the second dimension.

[0036] Furthermore, the first gap is both the entry point for dust into the pulley and the exit point for dust that has seeped into the pulley. By shortening the first dimension, even if dust seeps into the pulley from the first gap, it can easily be discharged from the outside of the pulley.

[0037] In scheme 3, the radial dimension of at least one of the first and second gaps is set to narrow towards the impeller side, based on the direction extending from the centerline of the bearing bore. Since the gap on the impeller side, which is the side where dust intrusion occurs, is set narrow, dust intrusion can be suppressed. This extends the pump's lifespan.

[0038] In scheme 4, dust that seeps in through the first gap may sometimes reach the edge of the opposite surface, which is opposite to the bottom of the pulley. The pulley is cylindrical with a bottom, and airflow occurs inside the pulley when it rotates. Therefore, the radially outward force caused by the airflow also acts on the dust. In addition to the connecting holes, recesses are also formed on the opposite surface. Some dust enters the recesses. Dust that enters the recesses will separate from the bearing. This keeps the dust away from the bearing, making it less likely for dust to seep into the bearing.

[0039] Even when dust enters the recess and moves towards the bearing, the distance it travels to reach the bearing is longer compared to when the dust moves on a flat surface without a recess. Dust is less likely to reach the bearing.

[0040] For the same reason mentioned above, dust is less likely to reach the outlet of the connecting hole. This extends the lifespan of the water pump.

[0041] In Scheme 5, the thickness of the large diameter section is thinner than that of the small diameter section, based on the radial direction of the small and large diameter sections. The recess is constructed using the space between the small and large diameter sections. Therefore, a larger recess can be formed between the small and large diameter sections. Dust can more easily penetrate into the recess. This allows dust to be separated from the bearing, making it less likely for dust to reach the bearing. This extends the lifespan of the water pump.

[0042] In Scheme 6, multiple ribs are formed from the outer peripheral surface of the small diameter portion to the inner peripheral surface of the large diameter portion. That is, the recess formed by utilizing the space between the small and large diameter portions is divided by multiple ribs. Therefore, when dust entering the recess moves along the surface of the recess towards the connecting hole, the ribs hinder the movement of the dust. This effectively prevents dust from approaching the connecting hole.

[0043] Furthermore, by forming ribs, the air inside the pulley easily becomes turbulent when the pulley rotates. The external force caused by the turbulence of the air is more likely to act on dust, making it less likely for dust to reach the bearings. This can extend the life of the water pump.

[0044] In embodiment 7, the centerline of the bearing bore extends horizontally, and at least a portion of the aforementioned recess formed on the opposite surface is located above the upper end of the bearing. Even if dust moves towards the bearing due to gravity, the dust will enter the recess formed at the upper end of the bearing, thus preventing dust from easily reaching the bearing. As a result, dust is less likely to penetrate the bearing, extending the lifespan of the water pump. Attached Figure Description

[0045] Figure 1 This is a cross-sectional view of a water pump according to an embodiment of the present invention.

[0046] Figure 2 yes Figure 1 The diagram shown is an exploded 3D view of the water pump.

[0047] Figure 3 This is an explanation Figure 2 The diagram shows the support portion of the water pump.

[0048] Figure 4 It is Figure 1 An enlarged view of a portion of the water pump shown.

[0049] Explanation of reference numerals in the attached figures

[0050] 10…water pump

[0051] 15… Impeller

[0052] 16…Mechanical seals (sealing components)

[0053] 30…bearing, 30a…upper end

[0054] 39…connecting holes

[0055] 40… Support section, 40a… Opposite surface

[0056] 41…bearing bore

[0057] 42…small diameter portion, 43…outer circumferential surface

[0058] 45…large diameter part, 44…outer peripheral surface

[0059] 50… Rotation axis

[0060] 51…the outer end (one end)

[0061] 52…the inner end (the other end)

[0062] 60…Pulley

[0063] 61…bottom, 64…inner surface

[0064] 62… cylindrical section, 68… inner circumferential surface

[0065] 65… cylinder

[0066] 66…Flange

[0067] 67…Second cylindrical section, 67a…Inner circumferential surface

[0068] 70…concave

[0069] 71…1st concave part

[0070] 72…2nd concave part

[0071] 73…3rd concave part

[0072] 81…First Rib

[0073] 82…2nd rib

[0074] 83…3rd rib

[0075] 84…4th rib

[0076] A1…First dimension (horizontal overlap dimension)

[0077] A2…Second dimension (horizontal overlap dimension)

[0078] B1…Radial dimension of the first gap

[0079] B2…Radial dimension of the second gap

[0080] C1…First Gap

[0081] C2…Second Gap Detailed Implementation

[0082] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0083] <Example>

[0084] Figure 1 The water pump 10 shown is an embodiment. This water pump 10 circulates cooling water used to cool the engine 11. The water pump 10 is fixed to the engine block 12 of heavy machinery such as excavators or vehicles, for example, by fastening members 13.

[0085] Reference Figure 1 , Figure 2 The housing 20 of the water pump 10 is a cast product, including: a plate-shaped fixing part 22 having a plurality (e.g., 5) fastening holes 21 through which the fastening member 13 passes; and a support part 40 having a bearing hole 41 for supporting the bearing 30.

[0086] The centerline L1 of the bearing hole 41 of the support part 40 extends in the horizontal direction. A cooling water flow path 23 is formed on the inner surface of the fixing part 22 (the surface on the side of the engine cylinder block 12). A sealing member 24 is provided between the housing 20 and the side surface 14 of the engine cylinder block 12.

[0087] Hereinafter, "inner side (In)" refers to the impeller 15 side described later, with the horizontal direction as the reference, and "outer side (Ou)" refers to the pulley 60 side described later. "below (Dn)" means vertically below, and "above (Up)" means vertically above.

[0088] The bearing 30 includes: an annular member 31 fitted into a bearing bore 41; and cylindrical rolling elements 32 and spherical rolling elements 33 disposed inside the annular member 31.

[0089] A rotating shaft 50, supported by a bearing 30 and rotatable, is provided in the bearing hole 41 of the support portion 40. The rotating shaft 50 passes through the bearing hole 41 axially. A belt-driven pulley 60 is provided at the outer end 51 (one end) of the rotating shaft 50. An impeller 15 is provided at the inner end 52 (the other end) of the rotating shaft 50. When the pulley 60 is driven, the impeller 15 provided on the rotating shaft 50 rotates, and cooling water is sent out through the flow path 23.

[0090] A mechanical seal 16 (sealing component) is provided between the impeller 15 and the bearing 30. The mechanical seal 16 fills the gap between the rotating shaft 50 and the bearing bore 41, preventing cooling water from entering the interior of the bearing bore 41. Detailed description of the mechanical seal 16 is omitted. Gaskets, oil seals, or other sealing components can also be used instead of the mechanical seal 16.

[0091] The pulley 60 is generally cylindrical with a bottom, including a circular plate-shaped bottom 61 and a hollow cylindrical portion 62 (first cylindrical portion) extending inward from the periphery 61a of the bottom 61. A fixing hole 63 is formed in the bottom 61, into which the outer end 51 of the rotating shaft 50 is pressed and fixed.

[0092] A cylindrical body 65 is provided on the inner surface 64 of the bottom 61. The cylindrical body 65 includes: an annular flange portion 66, which is welded to the inner surface 64 of the bottom 61 of the pulley 60; and a hollow cylindrical second cylindrical portion 67, which extends inward from the inner peripheral edge 66a of the radially inner side of the flange portion 66. In addition, the second cylindrical portion 67 may also be integrally formed with the pulley 60.

[0093] Reference Figure 3 When viewed from the direction along the centerline L1 (also known as the axial direction), the support portion 40 has: an annular small-diameter portion 42 with a bearing hole 41 formed at its center; and an annular large-diameter portion 45, the diameter of its outer peripheral surface 44 being larger than the diameter of the outer peripheral surface 43 of the small-diameter portion 42.

[0094] The large-diameter portion 45 surrounds the small-diameter portion 42 with the center line L1 as the center. With the radial direction of the small-diameter portion 42 and the large-diameter portion 45 as a reference, the thickness T1 of the large-diameter portion 45 is thinner than the thickness T2 of the small-diameter portion 42 (T1 < T2).

[0095] Reference Figure 1 The end face 46 of the smaller diameter portion 42 is located on the outer side (pulley side) of the end face 47 of the larger diameter portion 45. The outer peripheral surface 44 of the larger diameter portion 45 is inclined in such a way that its diameter decreases as it moves outward (inclination angle θ1). Similarly, the outer peripheral surface 43 of the smaller diameter portion 42 is inclined in such a way that its diameter decreases as it moves outward (inclination angle θ2).

[0096] Reference Figure 3 The annular space formed by the outer peripheral surface 43 of the small-diameter portion 42, the inner peripheral surface 48 of the large-diameter portion 45, and the bottom surface 25 of the fixing portion 22 is designated as the recess 70. This recess 70 is divided into six parts by a plurality of ribs 81 to 84 (e.g., four groups), as described below. The ribs 81 to 84 are formed radially from the outer peripheral surface 43 of the small-diameter portion 42 to the inner peripheral surface 48 of the large-diameter portion 45. The ribs 81 to 84 are positioned at equal intervals in the circumferential direction.

[0097] The rib that extends downward from the lower end 43a of the outer peripheral surface 43 of the small diameter portion 42 among the ribs 81 to 84 is designated as the first rib 81. The first rib 81 is block-shaped, and its circumferential dimension is set to be thicker than that of the other ribs 82 to 84.

[0098] Reference Figure 1 , Figure 3 A communication hole 39 is formed in the first rib 81, which connects the space 38 between the mechanical seal 16 in the bearing bore 41 and the bearing 30, and the outside of the support portion 40. The communication hole 39 includes: a first hole 35 extending radially outward from the space 38; and a second hole 36 communicating with the first hole 35 and extending outward. The outlet of the communication hole 39 is located at the end face 86 of the first rib 81.

[0099] The ribs that extend obliquely downward from the outer peripheral surface 43 of the small diameter portion 42 are designated as the second ribs 82 and 82, the ribs that extend obliquely upward from the outer peripheral surface 43 of the small diameter portion 42 are designated as the third ribs 83 and 83, and the ribs that extend upward from the upper end 43b of the outer peripheral surface 43 of the small diameter portion 42 are designated as the fourth rib 84.

[0100] The fourth rib 84 includes: a cylindrical portion 91 located approximately at the center of the radial direction; an inner wall portion 92 located radially inward of the cylindrical portion 91; and an outer wall portion 93 located radially outward of the cylindrical portion 91.

[0101] The end face 94 of the inner wall portion 92 is located further inward than the end face 95 of the cylindrical portion 91. The end face 96 of the outer wall portion 93 is inclined inward as it moves radially outward. The end face 95 of the cylindrical portion 91 is the face that is pressed when the housing 20 is separated from the metal mold.

[0102] Furthermore, ribs 82 and 83 are ribs of the same size / shape as rib 84. (Description omitted). Also, ribs 82 to 84 may be omitted, except for rib 81 which forms the connecting hole 39.

[0103] Reference Figure 3 When taking line L2, which is orthogonal to the center line L1 and extends vertically, as a reference, the support portion 40 is configured symmetrically from left to right. The configuration to the right of line L2 will be described below. Furthermore, this description also applies to the configuration to the left of line L2.

[0104] The space 38 between the first rib 81 and the second rib 82 is designated as the first recess 71. The space 38 between the second rib 82 and the third rib 83 is designated as the second recess 72. The space 38 between the third rib 83 and the fourth rib 84 is designated as the third recess 73. This description also applies to the configuration to the left of line L2. (Explanation omitted.)

[0105] Reference Figure 2 The surface of the outer peripheral surface 43 of the small-diameter portion 42 that forms part of the first recess 71 is designated as the first curved surface 74, the surface that forms part of the second recess 72 is designated as the second curved surface 75, and the surface that forms part of the third recess 73 is designated as the third curved surface 76. The surface of the outer peripheral surface 43 of the small-diameter portion 42 that is outermost from the ribs 81 to 84 is designated as the annular surface 77. Alternatively, the annular surface 77 can be described as the surface that does not form the recess 70.

[0106] Reference Figure 4 A first annular gap C1 is formed between the inner circumferential surface 68 of the cylindrical portion 62 of the pulley 60 and the outer circumferential surface 44 of the large-diameter portion 45. The annular surface 77 is located outside (Ou) of the outer circumferential surface 44 of the large-diameter portion 45. A second annular gap C2 is formed between the inner circumferential surface 67a of the second cylindrical portion 67 and the annular surface 77 of the small-diameter portion 42.

[0107] The outer peripheral surface 44 of the large-diameter section 45 is inclined in such a way that the diameter of the outer peripheral surface 44 increases as it moves inward (towards the impeller 15 side) (inclination angle θ (refer to...) Figure 1 Therefore, the radial dimension B1 of the first gap C1 increases as it moves inward (towards the impeller 15 side (refer to...)). Figure 1 The diameter of the small diameter portion 42 narrows as it moves inward. It is narrow on the inner side and wide on the outer side (pulley 60 side). Because it is narrow on the side where dust can easily get in, it can suppress the entry of dust. The outer peripheral surface 43 of the small diameter portion 42 is also inclined in the same way, achieving the same effect as described above. Moreover, the outer peripheral surface 43 of the small diameter portion 42 is inclined in such a way that the diameter of the outer peripheral surface 43 increases as it moves inward (impeller 15 side) (inclination angle θ2 (refer to...). Figure 1 Therefore, the radial dimension B2 of the second gap C2 increases as it moves inward (towards the impeller 15 side (see reference)). Figure 1It becomes narrower. It is narrow on the inside and wide on the outside (pulley 60 side). Because it is narrow on the side where dust can get in, it can suppress the entry of dust.

[0108] Using the horizontal direction (the direction in which the center line L1 of the rotation axis 50 extends) as a reference, the dimension in which the cylindrical portion 62 of the pulley 60 overlaps with the large-diameter portion 45 of the support portion 40 is taken as the first dimension A1. The dimension in which the second cylindrical portion 67 overlaps with the small-diameter portion 42 is taken as the second dimension A2. The first dimension A1 is shorter than the second dimension A2.

[0109] The second cylindrical portion 67 is located radially inward of the cylindrical portion 91 relative to the rotation axis 50. Therefore, the axial dimension of the water pump 10 can be shortened. The end face 69 of the second cylindrical portion 67 is located axially outward (Ou) of the end face 47 of the large-diameter portion 45. Similarly, the end face 69 is located axially outward (Ou) of the end faces 94 to 96. Alternatively, the second cylindrical portion 67 and the cylindrical portion 91 may overlap axially along the rotation axis 50 (reference line L3).

[0110] Reference Figure 1 , Figure 3 As a supplement, the bearing hole 41, the small diameter section 42, the large diameter section 45, the rotating shaft 50, the pulley 60, and the second cylindrical section 67 are positioned in a concentric circle with the center line L1 as the center.

[0111] The effects of the embodiments are explained.

[0112] Reference Figure 4 A first annular gap C1 is formed between the inner circumferential surface 68 of the cylindrical portion 62 of the pulley 60 and the outer circumferential surface 44 of the large-diameter portion 45. A cylindrical body 65 is provided at the bottom 61 of the pulley 60. A second annular gap C2 is formed between the second cylindrical portion 67 of the cylindrical body 65 and the small-diameter portion 42. That is, two gaps C1 and C2 are formed between the pulley 60 and the support portion 40 to inhibit the intrusion of dust. Therefore, dust is less likely to reach the interior of the bearing 30.

[0113] Furthermore, the second cylindrical portion 67 is provided at the bottom 61 of the pulley 60. Since the second cylindrical portion 67 is not fitted into the support portion 40, no external force is applied to the support portion 40. As a result, no load is applied to the bearing 30 provided on the support portion 40, thus extending the lifespan of the bearing 30.

[0114] Furthermore, a second cylindrical portion 67 is provided on the pulley 60, which is a rotating body. When the pulley 60 rotates, the second cylindrical portion 67 also rotates. Airflow is facilitated in the second gap C2 between the second cylindrical portion 67 and the small-diameter portion 42 of the support portion 40. Dust does not easily penetrate into the second gap C2.

[0115] Furthermore, the first dimension A1 is shorter than the second dimension A2. The first gap C1 is both the inlet for dust to enter the interior of the pulley 60 and the outlet for dust that has seeped into the interior. By shortening the first dimension A1, even if dust seeps into the interior of the pulley 60 from the first gap C1, the dust can easily be discharged from the first gap C1 to the outside of the pulley 60. In addition, the radial dimension B1 of the first gap C1 is the smallest at the innermost side. This smallest dimension is designated as dimension B11. The radial dimension B2 of the second gap C2 is the largest at the outermost side. This largest dimension is designated as dimension B21. For example, when dimension B11 is set to be larger than dimension B21 (B11 > B21), even if dust seeps into the interior of the pulley 60 from the first gap C1, the dust can easily be discharged from the first gap C1 to the outside of the pulley 60.

[0116] Reference Figure 1 Furthermore, the outer peripheral surface 44 of the large-diameter portion 45 is inclined (inclination angle θ) in such a way that the diameter of the outer peripheral surface 44 decreases as it moves outward (towards the pulley 60 side). Therefore, dust adhering to the surface of the outer peripheral surface 44 that is lower than the centerline L1 will move inward and separate from the bearing 30. Dust is less likely to penetrate into the bearing 30.

[0117] Explain other effects.

[0118] Reference Figure 1 , Figure 3 An annular first gap C1 is formed between the cylindrical portion 62 of the pulley 60 and the support portion 40 supporting the rotating shaft 50.

[0119] The end face of the support portion 40 that is opposite to the bottom 61 of the pulley 60 is designated as the opposing surface 40a (it can be said that the opposing surface 40a includes the end face 46 of the small diameter portion 42, the end face 47 of the large diameter portion 45, and the end faces 86 of the first rib 81 to the end faces 89 of the fourth rib 84). In the event of dust intrusion, dust may sometimes reach the edge of the opposing surface 40a (the end face 47 of the large diameter portion 45).

[0120] In addition to the through hole 39, a recess 70 is formed on the opposing surface 40a. The recess 70 includes a third recess 73 located above the upper end 30a of the bearing 30 (reference line L4). The opposing surface 40a faces horizontally, so dust moves downwards. However, the pulley 60 has a bottom cylindrical shape, and airflow occurs inside the pulley 60 when it rotates.

[0121] Not only gravity, but also external forces caused by airflow act on the dust. Some of this dust also enters the third recess 73 (recess 70). Dust entering the third recess 73 will separate from the bearing 30. This allows the dust to move horizontally away from the bearing 30, preventing dust from easily penetrating the bearing 30.

[0122] Even when dust enters the third recess 73 (recess 70) and moves toward the bearing 30, the distance it travels to reach the bearing 30 is longer compared to when the dust moves on a plane where the third recess 73 (recess 70) is not formed. Dust is less likely to reach the bearing 30.

[0123] For the same reason as described above, dust is less likely to reach the outlet of the connecting hole 39. This extends the lifespan of the water pump 10.

[0124] Furthermore, the radial thickness T1 of the large diameter portion 45 is thinner than the thickness T2 of the small diameter portion 42. Therefore, a larger recess 70 can be formed between the small diameter portion 42 and the large diameter portion 45. Dust can more easily penetrate into the recess 70. This allows dust to be separated from the bearing 30, making it less likely for dust to reach the bearing 30. This extends the service life of the water pump 10.

[0125] Furthermore, the recess 70 is divided by ribs 1 to 4, and ribs 2 to 4 are located above the connecting hole 39 (reference line L5). Even if dust entering the recess 70 moves along the surface of the recess 70 toward the connecting hole 39, ribs 2 to 4 will impede the flow of dust. This prevents dust from entering the connecting hole 39.

[0126] Furthermore, by forming the second rib 82 to the fourth rib 84, air turbulence easily occurs within the pulley 60. The external force caused by the air turbulence also easily acts on dust, making it less likely for dust to reach the bearing 30. This extends the service life of the water pump 10.

[0127] Furthermore, as long as the functions and effects of the present invention are achieved, the present invention is not limited to the embodiments. For example, the center line L1 of the bearing hole 41 of the support portion 40 is provided to extend in the horizontal direction, but the direction in which the center line L1 extends is not limited to this. Even if the center line L1 is provided to extend obliquely upward in the vertical direction or at the midpoint between the vertical and horizontal directions, the present invention will achieve the same effect.

[0128] Industrial availability

[0129] The water pump of the present invention is suitable for use in the engines of excavators, vehicles, etc.

Claims

1. A water pump, It comprises: a support portion having a bearing bore for supporting the bearing; a rotating shaft supported by the bearing and capable of rotation, and extending through the bearing bore; a bottomed cylindrical pulley disposed at one end of the rotating shaft; an impeller disposed at the other end of the rotating shaft; and a sealing member disposed between the impeller and the bearing. The support portion has a communication hole that connects the sealing member in the bearing hole with the space in front of the bearing and the outside of the support portion. The aforementioned water pump is characterized in that, The aforementioned support portion has: an annular small-diameter portion with the aforementioned bearing hole formed at its center; and an annular large-diameter portion, the diameter of the outer peripheral surface of which, centered on the aforementioned bearing hole, is larger than the diameter of the outer peripheral surface of the aforementioned small-diameter portion. At least a portion of the aforementioned smaller diameter portion is located on the pulley side closer to the larger diameter portion. An annular first gap is formed between the cylindrical portion of the pulley and the large-diameter portion. A second cylindrical section is provided at the bottom of the pulley, and an annular second gap is formed between the second cylindrical section and the small-diameter section. If the axial dimension of the overlap between the cylindrical portion of the pulley and the large-diameter portion of the support portion is taken as the first dimension. Taking the axial dimension of the overlap between the second cylindrical portion and the small-diameter portion of the support portion as the second dimension, then The first dimension mentioned above is shorter than the second dimension mentioned above.

2. The water pump according to claim 1, characterized in that, The radial dimension of at least one of the first gap and the second gap is set to narrow as it extends toward the impeller side, based on the direction extending from the centerline of the bearing hole.

3. The water pump according to claim 1, characterized in that, The aforementioned support portion has a facing surface that is opposite to the aforementioned bottom of the aforementioned pulley. In addition to the aforementioned connecting hole, a recess is also formed on the opposite side.

4. The water pump according to claim 3, characterized in that, The aforementioned large-diameter portion surrounds the aforementioned small-diameter portion. Based on the radial direction, the thickness of the larger diameter portion is thinner than the thickness of the smaller diameter portion. The aforementioned recess is formed by utilizing the space between the aforementioned small-diameter portion and the aforementioned large-diameter portion.

5. The water pump according to claim 4, characterized in that, Multiple ribs are formed from the outer peripheral surface of the aforementioned small-diameter portion to the inner peripheral surface of the aforementioned large-diameter portion.

6. The water pump according to claim 3, characterized in that, The centerline of the aforementioned bearing hole extends in the horizontal direction. At least a portion of the recess formed on the opposite surface is located above the upper end of the bearing.

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