阅读说明：本技术 泵 (Pump and method of operating the same ) 是由 加藤伸博 稻垣贵树 仲谷圭司 鸟居英将 于 2019-09-17 设计创作，主要内容包括：离心泵(10)具备：马达部(14),其在转子室(34)内以能够旋转的方式设有转子(32)；以及泵部(12),其在泵室(64)内以能够旋转的方式设有与转子(32)连结的叶轮(62)。在划分转子室(34)和泵室(64)的第2外壳构件(20)设有轴承(52),该轴承(52)以转子(32)的转子轴(48)旋转的方式支承转子(32)的转子轴(48)且被注入润滑脂。在第2外壳构件(20)形成有两个连通转子室(34)和泵室(64)的连通孔(81)。(A centrifugal pump (10) is provided with: a motor unit (14) in which a rotor (32) is rotatably provided in a rotor chamber (34); and a pump section (12) in which an impeller (62) connected to the rotor (32) is rotatably provided in the pump chamber (64). A bearing (52) is provided in a 2 nd housing member (20) that divides a rotor chamber (34) and a pump chamber (64), and the bearing (52) is filled with grease while supporting a rotor shaft (48) of a rotor (32) so that the rotor shaft (48) of the rotor (32) rotates. Two communication holes (81) for communicating the rotor chamber (34) and the pump chamber (64) are formed in the 2 nd housing member (20).)

1. A pump for pressurized delivery of a gas, wherein,

the pump is provided with:

a motor unit having a rotor rotatably provided in a rotor chamber; and

a pump section in which an impeller coupled to the rotor is rotatably provided in a pump chamber,

a bearing into which grease is injected is provided at a partition wall portion that divides the rotor chamber and the pump chamber, the bearing supporting a rotor shaft of the rotor so that the rotor shaft can rotate,

at least two breathing passages communicating the rotor chamber and the pump chamber are formed in the partition wall portion.

2. The pump of claim 1,

the openings of the at least two breathing passages on the pump chamber side are disposed at positions close to each other.

3. The pump according to claim 1 or 2,

an opening of at least one of the breathing passages on the pump chamber side is open at a portion on the pump chamber side of the bearing in the shaft hole of the partition wall through which the rotor shaft passes.

4. The pump according to any one of claims 1 to 3,

the discharge port of the pump chamber is arranged on the ground side of the pump chamber in the vertical direction in the vehicle-mounted state,

the bottom surface of the downstream end of the discharge port is disposed at a position lower than the bottom surface of the upstream end of the discharge port.

5. The pump of claim 4,

at least two of the breathing passages have openings on the pump chamber side arranged at a position higher than the rotor shaft.

6. A pump for pressurized delivery of a gas, wherein,

the pump is provided with:

a motor unit having a rotor rotatably provided in a rotor chamber; and

a pump section in which an impeller coupled to the rotor is rotatably provided in a pump chamber,

the discharge port of the pump chamber is arranged on the ground side of the pump chamber in the vertical direction in the vehicle-mounted state,

the bottom surface of the downstream end of the discharge port is disposed at a position lower than the bottom surface of the upstream end of the discharge port.

7. The pump of claim 6,

a guide recess portion that enlarges a passage area on a back side of the impeller and guides the liquid on the back side of the impeller toward the discharge port is formed at a lower end portion of the pump chamber.

8. The pump of claim 6,

a liquid accumulating portion having a bottom lower than a bottom on an inlet side of the discharge port is formed at a lower end portion of the pump chamber.

Technical Field

The present disclosure relates to a pump.

Background

Jp 2012-17712 a discloses a conventional pump for pressurized delivery of a gas, the pump comprising: a motor unit having a rotor rotatably provided in a rotor chamber; and a pump section in which an impeller coupled to the rotor is rotatably provided in the pump chamber.

Disclosure of Invention

Problems to be solved by the invention

(problem 1)

In japanese patent application laid-open No. 2012-17712, a bearing including a ball bearing for rotatably supporting a rotor shaft is provided in a partition wall portion that divides a rotor chamber and a pump chamber. Grease for lubrication is injected into the bearing. A communication hole for communicating the rotor chamber and the pump chamber is formed in the partition wall portion. In jp 2012-17712 a, a flow of gas from the pump chamber to the rotor chamber through the communication hole is generated by the operation of a suction device that sucks the grease from the rotor chamber, thereby suppressing leakage of the grease. However, this requires a suction device, which results in high costs. When the suction device is omitted, a ring flow path is formed to return from the pump chamber to the pump chamber through the rotor chamber by a communication gap formed by a gap between the members of the bearing and a communication hole of the partition wall. Therefore, the grease leaks out due to the passage of the gas through the bearing.

The present disclosure is directed to provide a pump capable of suppressing leakage of grease from a bearing with a simple and inexpensive structure.

(problem 2)

In the pump disclosed in japanese patent application laid-open No. 2012 and 17712, the pump is not assumed to be mounted on a vehicle. Therefore, in a vehicle-mounted state of the pump, a liquid such as water generated by condensation or the like in the pump chamber remains in the pump chamber, and there is a possibility that a malfunction of the impeller due to freezing may occur.

The present disclosure is directed to provide a pump capable of improving liquid discharge performance of a pump chamber and suppressing a malfunction of an impeller due to freezing.

Means for solving the problems

The technical problem can be solved by the following technical means.

(claim 1)

The 1 st aspect of the present disclosure is a pump for pressurizing and conveying a gas, the pump including: a motor unit having a rotor rotatably provided in a rotor chamber; and a pump section in which an impeller coupled to the rotor is rotatably provided in a pump chamber, wherein a bearing that supports the rotor shaft of the rotor so that the rotor shaft can rotate and into which grease is injected is provided in a partition wall section that partitions the rotor chamber and the pump chamber, and wherein at least two breathing passages that communicate the rotor chamber and the pump chamber are formed in the partition wall section.

According to claim 1, the annular flow path that returns from the pump chamber to the pump chamber via the rotor chamber is formed by at least two breathing paths provided in a partition wall portion that partitions the rotor chamber and the pump chamber. Therefore, the gas preferentially flows through the circulation path bypassing the bearing, and therefore, the grease of the bearing can be suppressed from leaking out. Further, unlike the pump disclosed in japanese patent application laid-open No. 2012-17712, since a suction device is not required, leakage of grease from the bearing can be suppressed with a simple and inexpensive structure.

(claim 2)

The invention according to claim 2 is a pump for pressurizing and delivering a gas, the pump including: a motor unit having a rotor rotatably provided in a rotor chamber; and a pump section in which an impeller coupled to the rotor is rotatably provided in a pump chamber, wherein a discharge port of the pump chamber is disposed on a ground side of the pump chamber in a vehicle-mounted state, and a bottom surface of a downstream end of the discharge port is disposed at a position lower than a bottom surface of an upstream end of the discharge port.

According to claim 2, the liquid in the pump chamber can be discharged from the spout by utilizing natural flow. This improves the liquid discharge performance of the pump chamber, and can suppress the operation failure of the impeller due to freezing.

ADVANTAGEOUS EFFECTS OF INVENTION

(1 st Effect)

According to the pump disclosed by the invention, the leakage of the grease of the bearing can be inhibited by using a simple and cheap structure.

(effect 2)

According to the pump of the present disclosure, the liquid discharge performance of the pump chamber can be improved, and the operation failure of the impeller due to freezing can be suppressed.

Drawings

Fig. 1 is a front view showing a centrifugal pump according to embodiment 1.

Fig. 2 is a sectional view taken along line II-II of fig. 1, the centrifugal pump including a No. 2 housing member.

Fig. 3 is a sectional view showing a main part of the centrifugal pump of fig. 2.

Fig. 4 is a front view showing the 2 nd housing member.

Fig. 5 is a sectional view taken along line V-V of fig. 4.

Fig. 6 is a sectional view showing a main part of the centrifugal pump of embodiment 2.

Fig. 7 is a sectional view showing a main part of the centrifugal pump of embodiment 3.

Fig. 8 is a sectional view showing a main part of the centrifugal pump of embodiment 4.

Fig. 9 is a front view showing a 2 nd housing member of embodiment 5.

Fig. 10 is a sectional view showing a main part of the centrifugal pump of embodiment 6.

Fig. 11 is a sectional view showing a main part of the centrifugal pump of embodiment 7.

Fig. 12 is a sectional view showing a main part of the centrifugal pump of embodiment 8.

Fig. 13 is a sectional view showing a main part of a centrifugal pump according to embodiment 9.

Detailed Description

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[ embodiment 1]

In embodiment 1, a centrifugal pump used as a purge pump mounted on a vehicle such as an automobile is exemplified. The purge pump is a pump that fills the flow rate of the purge gas flowing from the canister to the intake passage of the internal combustion engine (engine). Fig. 1 is a front view showing a centrifugal pump, fig. 2 is a sectional view taken along line II-II of fig. 1, and fig. 3 is a sectional view showing a main part of the centrifugal pump. The directions in the drawing indicate the front-rear, left-right, and up-down directions of the centrifugal pump. The vertical direction corresponds to the vertical direction based on the gravity direction in the vehicle mounted state of the centrifugal pump. The front-rear-left-right direction is not limited to the arrangement direction of the centrifugal pump. Further, the centrifugal pump corresponds to a "pump" in this specification.

(outline of centrifugal Pump)

As shown in fig. 2, the centrifugal pump 10 includes a pump section 12 and a motor section 14 arranged in an axial direction (front-rear direction). The casing 16 of the centrifugal pump 10 includes a 1 st casing member 18, a 2 nd casing member 20, and a 3 rd casing member 22 that are axially three-sectioned.

The 1 st housing member 18 and the 2 nd housing member 20 are fastened with a plurality of screws or the like. The 2 nd and 3 rd housing members 20 and 22 are fastened with a plurality of screws or the like. An O-ring (not shown) for sealing between the 1 st housing member 18 and the 2 nd housing member 20 is interposed therebetween. An O-ring (not shown) is interposed between the 2 nd and 3 rd casing members 20 and 22 to seal therebetween. The 1 st housing member 18, the 2 nd housing member 20, and the 3 rd housing member 22 are made of resin, respectively.

(Motor section 14)

The motor unit 14 includes a brushless motor, and includes a stator 30 and a rotor 32. The 2 nd and 3 rd housing members 20 and 22 constitute a motor housing that forms a hollow cylindrical rotor chamber 34. The 3 rd housing member 22 includes a cylindrical tubular portion 36 extending in the front-rear direction, an extended tubular portion 37 extending rearward from an inner peripheral portion of a rear end surface of the tubular portion 36, and a rear wall portion 38 closing a rear surface opening of the extended tubular portion 37. A stepped recess 39 is formed in the inner periphery of the front end surface of the cylindrical wall 36. A cylindrical metal holder 40 is provided in the extension tube portion 37.

The stator 30 is embedded in the cylindrical wall portion 36 by insert molding, and is entirely covered with a mold resin as the cylindrical wall portion 36. The stator 30 includes a stator core, a stator coil, and the like, and is formed in an annular shape.

The 2 nd housing member 20 is formed in a circular ring plate shape. A hollow cylindrical boss 42 is formed concentrically in the center of the rear surface of the 2 nd housing member 20. As shown in fig. 3, an axial hole 43 is formed in the boss 42 so as to pass through in the axial direction. The boss portion 42 is fitted into the distal end portion of the cylindrical wall portion 36 of the 3 rd housing member 22 with a predetermined gap.

An annular ring-shaped protrusion 46 is concentrically formed on the rear surface of the 2 nd housing member 20, and the ring-shaped protrusion 46 surrounds the hub 42 at a predetermined interval. The annular projection 46 is formed in a quadrangular cross-sectional shape. The annular projection 46 is fitted into the front end opening of the stepped recess 39 of the 3 rd housing member 22.

As shown in fig. 2, a rotor 32 is rotatably provided in the rotor chamber 34. The rotor 32 includes a rotor shaft 48 and a permanent magnet 50. The rotor shaft 48 is made of, for example, a solid shaft made of metal. The permanent magnet 50 is disposed at the center in the axial direction of the rotor shaft 48 so that a plurality of magnetic poles are arranged in the circumferential direction. The distal end portion of the rotor shaft 48 is rotatably supported in the boss portion 42 of the 2 nd housing member 20 via a bearing 52.

As shown in fig. 3, the bearing 52 is formed of a ball bearing, and has an outer ring 53, an inner ring 54, and balls 55. The inner ring 54 is press-fitted into the rotor shaft 48 from the front of the rotor shaft 48. The outer ring 53 is press-fitted into the boss 42 of the 2 nd housing member 20 from the rear. The rotor shaft 48 has a distal end portion on the output side and penetrates the center portion of the boss portion 42 of the 2 nd housing member 20.

As shown in fig. 2, the rear end portion of the rotor shaft 48 is rotatably supported in the holder 40 of the 3 rd housing member 22 via an auxiliary bearing 57. The auxiliary bearing 57 includes a ball bearing having an outer race, an inner race, and balls. The inner ring is fixed to the rotor shaft 48, and the outer ring is embedded with a gap in the holder 40. A rotation stop mechanism for stopping rotation of the outer ring of the 3 rd housing member 22 and the auxiliary bearing 57 is provided between the outer ring.

A control circuit (not shown) for controlling the power supply to the stator 30 is provided on the rear side of the 3 rd housing member 22. An external connector connected to an external power supply is connected to a connector portion (not shown) formed in the 3 rd housing member 22. The motor unit 14 is driven by supplying electric power from an external power supply.

(Pump section 12)

As shown in fig. 2, the pump section 12 includes an impeller 62 that is rotated by the motor section 14. The 1 st housing member 18 and the 2 nd housing member 20 constitute a pump housing that forms a hollow cylindrical pump chamber 64 that is short in the axial direction. A hollow cylindrical suction port 66 protruding forward is formed in the center of the 1 st housing member 18. A suction port 67 for communicating the inside and outside of the pump chamber 64 is formed in the suction port 66.

The 1 st housing member 18 is formed in a short cylindrical shape with the rear surface side open. An annular flow channel 69 is formed concentrically in the outer periphery of the rear surface (the surface on the pump chamber 64 side) of the front wall portion of the 1 st housing member 18 along the outer periphery of the pump chamber 64. The flow channel 69 is formed to have a substantially semicircular cross section. Fig. 4 is a front view showing a 2 nd housing member, and fig. 5 is a V-V line sectional view of fig. 4.

As shown in fig. 4, an annular wall 72 is formed concentrically on the front surface side of the 2 nd housing member 20. As shown in fig. 5, the annular wall 72 is formed in a quadrangular sectional shape. As shown in fig. 2, the outer peripheral portion of the annular wall 72 is fitted to the inner peripheral portion of the 1 st housing member 18. The 2 nd housing member 20 corresponds to a "partition wall portion" in the present specification.

As shown in fig. 1, a hollow cylindrical discharge port 74 is formed at the lower end of the 1 st housing member 18. The discharge port 74 protrudes outward in the tangential direction, i.e., outward in the right-hand direction, from the outer peripheral portion of the 1 st housing member 18 in the front view. An ejection port 75 is formed in the ejection port 74. As shown in fig. 2, the discharge port 75 extends in the tangential direction of the flow path groove 69, and the upstream end thereof communicates with the lower end portion of the pump chamber 64. The bottom surface 75a at the upstream end of the discharge port 75 is connected to the lower end portion of the outer peripheral surface of the pump chamber 64.

As shown in fig. 1, the discharge port 75 is disposed on the ground side in the vertical direction in the vehicle mounted state of the centrifugal pump 10. The bottom surface 75b of the downstream end of the discharge port 75 is disposed at a position lower than the bottom surface 75a of the upstream end of the discharge port 75. Thereby, the bottom surface of the discharge port 75 is inclined obliquely downward from the upstream end bottom surface 75a toward the downstream end bottom surface 75 b.

As shown in fig. 2, the impeller 62 is rotatably housed in the pump chamber 64. The impeller 62 includes a disk-shaped base plate portion 77, a hollow cylindrical shaft portion 79 formed concentrically on the rear surface of the base plate portion 77, and a plurality of blade portions (not shown) formed at predetermined intervals in the circumferential direction on the center portion of the front surface of the base plate portion 77. The substrate portion 77 is disposed in the annular wall 72 of the 2 nd housing member 20. As shown in fig. 3, the barrel shaft portion 79 is rotatably fitted in the shaft hole 43 of the 2 nd housing member 20.

The tip end portion of the rotor shaft 48 is fitted into the cylindrical shaft portion 79 of the impeller 62, and the impeller 62 rotates integrally with the rotation of the rotor 32. A slight gap is set between the base plate portion 77 of the impeller 62 and the opposing surface of the 2 nd housing member 20.

(action of centrifugal Pump 10)

The motor unit 14 is driven by electric power supplied from an external power supply. Then, the impeller 62 rotates together with the rotor 32, and the purge gas is sucked as a gas into the pump chamber 64 from the suction port 67. The purge gas is pressurized by the rotation of the impeller 62 and then ejected from the ejection port 75. In this manner, the purge gas is pressurized by the centrifugal pump 10.

(characteristic structure of embodiment 1)

As shown in fig. 3 to 5, the 2 nd housing member 20 is provided with two linear communication holes 81 that communicate the rotor chamber 34 and the pump chamber 64. Each communication hole 81 has a front end opening 81a that opens near the shaft hole 43 on the front surface of the 2 nd housing member 20 on the pump chamber 64 side, and a rear end opening 81b on the opposite side from the front end opening 81 a.

As shown in fig. 4, the front end opening 81a and the rear end opening 81b of each communication hole 81 are arranged in a radial direction of the 2 nd housing member 20. The two communication holes 81 are disposed at a position higher than the rotor shaft 48. That is, the distal end openings 81a of the two communication holes 81 are disposed at a position higher than the rotor shaft 48. The two communication holes 81 are arranged at positions shifted by about 90 ° about the axis 20L of the 2 nd housing member 20. Thereby, the distal end openings 81a of the two communication holes 81 are disposed at positions close to each other. The communication hole 81 corresponds to a "breathing passage" in this specification. In the present specification, the "positions close to each other" means, for example, positions where the shortest distance between the distal end openings 81a of the two adjacent communication holes 81 is equal to or less than the diameter of the shaft hole 43.

(advantages of characteristic Structure of embodiment 1)

According to embodiment 1, the two communication holes 81 provided in the 2 nd housing member 20 that divides the rotor chamber 34 and the pump chamber 64 form a loop flow path that returns from the pump chamber 64 to the pump chamber 64 through the rotor chamber 34. That is, one of the communication holes 81 serves as a flow path from the pump chamber 64 to the rotor chamber 34, and the other communication hole 81 serves as a flow path from the rotor chamber 34 to the pump chamber 64. Therefore, since the purge gas preferentially flows in the circulation path bypassing the bearing 52, the grease of the bearing 52 can be suppressed from leaking out. Further, unlike the pump disclosed in japanese patent application laid-open No. 2012-17712, since a suction device is not required, grease leakage from the bearing 52 can be suppressed with a simple and inexpensive structure.

The distal end openings 81a of the two communication holes 81 are disposed at positions close to each other. Therefore, by reducing the pressure difference between the two communication holes 81, the grease leakage from the bearing 52 can be further suppressed.

Further, discharge port 75 of pump chamber 64 is arranged on the heaven-earth direction side of pump chamber 64 in the vehicle mounted state, and bottom surface 75b of the downstream end of discharge port 75 is arranged at a position lower than bottom surface 75a of the upstream end of discharge port 75. Therefore, the liquid in the pump chamber 64 can be discharged from the discharge port 75 by natural flow. This improves the liquid discharge performance of pump chamber 64, and suppresses malfunction of impeller 62 due to freezing.

The distal end openings 81a of the two communication holes 81 are disposed at a position higher than the rotor shaft 48. Therefore, it is possible to suppress liquid such as water generated by condensation or the like in the pump chamber 64 from entering the rotor chamber 34 through the communication hole 81. This can improve the durability of the motor unit 14.

[ embodiment 2]

Embodiment 2 is modified from embodiment 1, and therefore, the modified portions will be described, and redundant description will not be given. Fig. 6 is a sectional view showing a main part of the centrifugal pump. As shown in fig. 6, in embodiment 2, a distance R1 from the axis 20L of the case member 20 of fig. 2 to the center of the front end opening 81a of one (upper side in fig. 6) communication hole 81 and a distance R2 from the axis 20L to the center of the front end opening 81a of the other communication hole 81 are set to be different distances. Namely, the distances R1 and R2 are set to R1 > R2.

[ embodiment 3]

Embodiment 3 is modified from embodiment 1, and therefore, the modified portions will be described, and redundant description will not be given. Fig. 7 is a sectional view showing a main part of the centrifugal pump. As shown in fig. 7, in embodiment 3, a front end opening portion 82a of one (upper side in fig. 7) communication hole 82 opens in the shaft hole 43 of the 2 nd housing member 20. The distal end opening 82a is disposed on the front side (pump chamber 64 side) of the shaft hole 43 with respect to the bearing 52. In embodiment 3, one breathing passage 85 is formed by one communication hole 82 and a gap between the shaft hole 43 of the 2 nd housing member 20 and the cylindrical shaft portion 79 of the impeller 62.

According to embodiment 3, the breathing passage 85 can be communicated with the portion on the lowest pressure side of the pump chamber 64. Further, the distal end opening 81a of the communication hole 81 may also be opened in the shaft hole 43 of the 2 nd housing member 20 at a position further toward the front side than the bearing 52.

[ embodiment 4]

Embodiment 4 is a modification of embodiment 3, and therefore, the modified portions will be described and redundant description will be omitted. Fig. 8 is a sectional view showing a main part of the centrifugal pump. As shown in fig. 8, in embodiment 4, a communication groove 87 linearly extending from the front end opening 82a of the one through hole 82 toward the pump chamber 64 is formed in the inner peripheral surface of the shaft hole 43 of the 2 nd housing member 20. In embodiment 4, one breathing passage 89 is formed by the one through hole 82, the gap between the shaft hole 43 of the 2 nd housing member 20 and the cylindrical shaft portion 79 of the impeller 62, and the communication groove 87.

Further, when the opening areas of the communication hole 81 and the communication groove 87 are set to be the same or substantially the same, grease leakage from the bearing 52 is effectively suppressed. The communication hole 81 may have the same structure as the breathing passage 89.

[ embodiment 5]

Embodiment 5 is modified from embodiment 1, and therefore, the modified portions will be described, and redundant description will not be given. Fig. 9 is a front view showing the 2 nd housing member. As shown in fig. 9, the two communication holes 81 in embodiment 5 are disposed at a position lower than the rotor shaft 48. According to embodiment 5, the liquid to be stored in the two communication holes 81 can be discharged by natural flow.

[ embodiment 6]

Embodiment 6 is a modification of embodiment 1, and therefore, the modified portions will be described and redundant description will be omitted. Fig. 10 is a sectional view showing a main part of the centrifugal pump. As shown in fig. 10, a guide recess 92 is formed in the lower end portion of the annular wall 72 of the 2 nd housing member 20. The guide recess 92 has a guide surface 93 inclined obliquely downward from the rear side toward the front side. The passage area on the back side of the impeller 62 at the lower end portion of the pump chamber 64 is enlarged by the guide recess 92. The guide surface 93 of the guide recess 92 guides the liquid on the back side of the impeller 62 toward the ejection port 75.

According to embodiment 6, the surface tension of the liquid accumulated on the back side of the impeller 62 at the lower end portion of the pump chamber 64 is reduced by the guide concave portion 92, and the liquid can be made to flow down naturally toward the ejection port 75 quickly. This can further improve the liquid discharge performance of the pump chamber 64.

[ embodiment 7]

Embodiment 7 is modified from embodiment 1, and therefore, the modified portions will be described, and redundant description will not be given. Fig. 11 is a sectional view showing a main part of the centrifugal pump. As shown in fig. 11, a guide recess 95 is formed in the inner peripheral portion of the lower end portion of the annular wall 72 of the 2 nd housing member 20. The rear surface 96 of the guide recess 95 is formed on the same plane as the front wall surface of the 2 nd housing member 20. The passage area on the back side of the impeller 62 at the lower end portion of the pump chamber 64 is enlarged by the guide recess 95. The lower surface 97 of the guide recess 95 is formed horizontally. The lower surface 97 of the guide recess 95 guides the liquid on the back side of the impeller 62 toward the ejection port 75.

According to embodiment 7, the surface tension of the liquid accumulated on the back side of the impeller 62 at the lower end portion of the pump chamber 64 is reduced by the guide recess 95, and the liquid can be made to flow down naturally toward the discharge port 75 quickly. This can further improve the liquid discharge performance of the pump chamber 64.

[ embodiment 8]

Embodiment 8 is modified from embodiment 1, and therefore, the modified portions will be described, and redundant description will not be given. Fig. 12 is a sectional view showing a main part of the centrifugal pump. As shown in fig. 12, a guide groove 100 penetrating in the vertical direction is formed in the lower end portion of the annular wall 72 of the 2 nd housing member 20. The passage area on the back side of the impeller 62 at the lower end portion of the pump chamber 64 is enlarged by the guide groove 100. A concave liquid accumulation portion 102 is formed at a lower end portion of the outer peripheral surface of the pump chamber 64 of the 1 st housing member 18. The liquid trap 102 is disposed at the lower end of the pump chamber 64. The liquid collecting portion 102 has a bottom lower than the bottom surface 75a at the upstream end of the discharge port 75.

According to embodiment 8, the surface tension of the liquid accumulated on the back surface side of the impeller 62 at the lower end portion of the pump chamber 64 is reduced by the guide groove 100, and the liquid can be made to flow down naturally and quickly. Further, the liquid flowing down from the back side of the impeller 62 at the lower end portion of the pump chamber can be accumulated in the liquid accumulating portion 102 and discharged to the discharge port 75.

[ embodiment 9]

Embodiment 9 is a modification of embodiment 8, and therefore, the modified portions will be described and redundant description will be omitted. Fig. 13 is a sectional view showing a main part of the centrifugal pump. As shown in fig. 13, in embodiment 9, a lateral frame portion 104 in the circumferential direction of the lateral frame is formed at the upper front corner of the guide groove 100 in embodiment 8. A partition 106 that partitions the space between the cross frame portion 104 and the 2 nd housing member 20 into a plurality of spaces in the circumferential direction is provided between the cross frame portion 104 and the 2 nd housing member 20.

According to embodiment 9, by providing the lateral frame portion 104 and the partition portion 106 in the guide groove 100, the pressure loss from the pump chamber 64 to the liquid accumulating portion 102 can be suppressed. The partition 106 may be omitted.

[ other embodiments ]

The present disclosure is not limited to the above-described embodiments, and modifications can be made without departing from the scope of the present disclosure. For example, the pump of the present disclosure may be applied to a pump used for pressurized delivery of a gas other than a purge gas such as air. In addition, the present disclosure may also be applied to pumps other than centrifugal pumps. In addition, the brushless motor of the motor unit 14 may be replaced with a brush motor. In addition, the number of breathing passages may be increased to three or more. The shape, arrangement, and the like of the breathing passage may be appropriately changed.

The present disclosure has been made in various forms. The 1 st aspect is a pump for pressurizing and conveying a gas, the pump including: a motor unit having a rotor rotatably provided in a rotor chamber; and a pump section in which an impeller coupled to the rotor is rotatably provided in a pump chamber, wherein a bearing that supports the rotor shaft of the rotor so that the rotor shaft can rotate and into which grease is injected is provided in a partition wall section that partitions the rotor chamber and the pump chamber, and wherein at least two breathing passages that communicate the rotor chamber and the pump chamber are formed in the partition wall section.

According to the first aspect, the annular flow path that returns from the pump chamber to the pump chamber through the rotor chamber is formed by at least two breathing paths provided in a partition wall portion that divides the rotor chamber and the pump chamber. Therefore, the gas flows preferentially in the circulation path bypassing the bearing, and hence the grease of the bearing can be suppressed from leaking out. Further, unlike the pump disclosed in japanese patent application laid-open No. 2012-17712, since a suction device is not required, leakage of grease from the bearing can be suppressed with a simple and inexpensive structure.

The pump according to claim 2 is the pump according to claim 1, wherein the opening portions of at least two of the breathing passages on the pump chamber side are disposed at positions close to each other.

According to the embodiment 2, the grease leakage from the bearing can be further suppressed by reducing the pressure difference between the at least two breathing passages.

The 3 rd aspect is the pump according to the 1 st or 2 nd aspect, wherein an opening portion of at least one of the breathing passages on the pump chamber side is opened at a portion on the pump chamber side of the bearing in a shaft hole of the partition wall portion through which the rotor shaft passes.

According to the 3 rd aspect, at least one breathing passage can be communicated with the portion on the lowest pressure side of the pump chamber.

The 4 th aspect is the pump according to any one of the 1 st to 3 th aspects, wherein a discharge port of the pump chamber is disposed on a vehicle-mounted state on a ground side in a vertical direction of the pump chamber, and a bottom surface of a downstream end of the discharge port is disposed at a position lower than a bottom surface of an upstream end of the discharge port.

According to the 4 th aspect, the liquid in the pump chamber can be discharged from the spout by natural flow. This improves the liquid discharge performance of the pump chamber, and can suppress the operation failure of the impeller due to freezing.

The 5 th aspect is the pump according to the 4 th aspect, wherein the opening portions of at least two of the breathing passages on the pump chamber side are disposed at a position higher than the rotor shaft.

According to the 5 th aspect, the liquid in the pump chamber can be suppressed from entering the rotor chamber through the breathing passage. This can improve the durability of the motor unit.

The 6 th aspect is a pump for pressurizing and delivering a gas, the pump including: a motor unit having a rotor rotatably provided in a rotor chamber; and a pump section in which an impeller coupled to the rotor is rotatably provided in a pump chamber, wherein a discharge port of the pump chamber is disposed on a ground side of the pump chamber in a vehicle-mounted state, and a bottom surface of a downstream end of the discharge port is disposed at a position lower than a bottom surface of an upstream end of the discharge port.

According to the 6 th aspect, the liquid in the pump chamber can be discharged from the spout by natural flow. This improves the liquid discharge performance of the pump chamber, and can suppress the operation failure of the impeller due to freezing.

The 7 th aspect is the pump according to the 6 th aspect, wherein a guide recess portion that enlarges a passage area on a back side of the impeller and guides the liquid on the back side of the impeller toward the discharge port is formed in a lower end portion of the pump chamber.

According to the 7 th aspect, the surface tension of the liquid accumulated on the back surface side of the impeller at the lower end portion of the pump chamber is reduced by the guide concave portion, and the liquid can be made to flow down naturally toward the discharge port quickly. This can further improve the liquid discharge performance of the pump chamber.

The 8 th aspect is the pump according to the 6 th aspect, wherein a liquid accumulating portion having a bottom lower than a bottom on an inlet side of the discharge port is formed at a lower end portion of the pump chamber.

According to the 8 th aspect, the liquid flowing down from the back side of the impeller at the lower end portion of the pump chamber can be accumulated in the liquid accumulation portion and discharged to the discharge port.