CN111140501B

CN111140501B - Vacuum pump

Info

Publication number: CN111140501B
Application number: CN201911037697.9A
Authority: CN
Inventors: 小仓崇宽
Original assignee: Mikuni Corp
Current assignee: Mikuni Corp
Priority date: 2018-11-06
Filing date: 2019-10-29
Publication date: 2023-01-06
Anticipated expiration: 2039-10-29
Also published as: JP7197329B2; JP2020076339A; CN111140501A

Abstract

The technical problem is as follows: provided is a vacuum pump capable of suppressing the influence of a liquid entering from an exhaust port on the operation of a movable part. The solution is as follows: it is provided with: a pump housing (10) that includes a pump chamber (5), a first muffling chamber (12) through which gas discharged from the pump chamber (5) passes, and an exhaust port (14) for discharging the gas that has passed through the first muffling chamber (12) to the outside; and a movable section (4) for sucking gas into the pump chamber (5) and discharging gas from the pump chamber (5), wherein the pump housing (10) includes a cylindrical section (44) protruding upward in the first muffling chamber (12), and the gas discharged from the pump chamber (5) flows into the first muffling chamber (12) through an internal space of the cylindrical section (44).

Description

Vacuum pump

Technical Field

The present disclosure relates to a vacuum pump.

Background

Conventionally, as described in patent document 1, for example, a vacuum pump is used in some cases to make a negative pressure in a negative pressure chamber of a brake booster in a vehicle such as an automobile. The vacuum pump includes a pump chamber and a movable portion for sucking gas into the pump chamber and discharging gas from the pump chamber.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2014-25413

Disclosure of Invention

Technical problem to be solved

The vacuum pump described above sometimes enters liquid such as splash from the exhaust port during vehicle running or the like depending on the place where the vacuum pump is mounted, such as the rear of the tire, the place close to the ground, or the like. If the liquid entering from the discharge port flows into the pump chamber, the movable portion may not operate normally, and the pump function may not be performed.

In this regard, patent document 1 does not disclose a finding about an influence of a liquid entering from an exhaust port of a vacuum pump on an operation of a movable portion and a countermeasure therefor.

At least one embodiment of the present invention has been made in view of the above-described problems of the related art, and an object thereof is to provide a vacuum pump capable of suppressing the influence of liquid entering from an exhaust port on the operation of a movable portion.

(II) technical scheme

(1) A vacuum pump according to at least one embodiment of the present invention includes: a pump housing that forms a pump chamber, a first muffling chamber through which gas discharged from the pump chamber passes, and an exhaust port for discharging the gas that has passed through the first muffling chamber to the outside; and a movable portion for sucking gas into the pump chamber and discharging gas from the pump chamber; the pump housing includes a cylindrical portion protruding upward in the first muffler chamber, and is configured to allow gas discharged from the pump chamber to flow into the first muffler chamber through an internal space of the cylindrical portion.

(2) In some embodiments, in the vacuum pump according to the above (1), an upper end of the cylindrical portion may be located higher than an upper end of the exhaust port.

(3) In some embodiments, in the vacuum pump according to the above (1) or (2), the pump housing may include a first member that forms a bottom surface of the first muffling chamber, the cylindrical portion may protrude upward from the bottom surface of the first muffling chamber, and the cylindrical portion and the first member may be formed integrally of the same material.

(4) In some embodiments, in the vacuum pump according to any one of the above (1) to (3), the pump housing may form a second muffling chamber that is provided below the first muffling chamber and through which the gas discharged from the pump chamber passes, a bottom surface of the second muffling chamber being provided below a bottom surface of the pump chamber, and the first muffling chamber and the second muffling chamber may be configured to communicate with each other via an internal space of the cylindrical portion.

(5) In some embodiments, in the vacuum pump according to any one of (1) to (4), a bottom surface of the first muffling chamber may include a tapered surface that is inclined downward as approaching the exhaust port.

(6) In some embodiments, in the vacuum pump according to any one of the above (1) to (5), a bottom surface of the first muffling chamber may include: a first bottom surface portion; and a second bottom surface portion adjacent to the first bottom surface portion and formed as a support surface for the fastening member at a position higher than the first bottom surface portion.

(7) In some embodiments, in the vacuum pump according to (6) above, the movable portion may include: a rotor disposed in the pump chamber and having a plurality of slits formed in an outer circumferential surface thereof; and a plurality of blades respectively arranged on the plurality of slits.

(III) advantageous effects

According to at least one embodiment of the present invention, there is provided a vacuum pump capable of suppressing influence of a liquid entering from an exhaust port on an operation of a movable portion.

Drawings

Fig. 1 is a schematic partial cut-away sectional view of a vacuum pump 2 of one embodiment.

Fig. 2 is a schematic partial cross-sectional view showing a state in which the vacuum pump 2 is partially submerged.

Fig. 3 is a schematic partial cross-sectional view showing a state in which the vacuum pump 2 is entirely submerged.

Fig. 4 is a schematic partially cut-away cross-sectional view for explaining the shape of the bottom surface 22 of the muffling chamber 12 of the vacuum pump 2.

Fig. 5 is a partially enlarged view of the bottom surface 22 of the muffling chamber 12 shown in fig. 4.

Description of the reference numerals

2-a vacuum pump; 4-a movable part; 5-a pump chamber; 10-a pump housing; 12-an anechoic chamber (first anechoic chamber); 14-an exhaust port; 18-pump cover (first part); 20-upper end; 22-bottom surface; 24-an anechoic chamber; 26-bottom surface; 28-conical surface; 30-a first bottom surface portion; 32-screw (fastening means); 34-a second bottom surface portion; 36-cutting and cutting; 38-a rotor; 39-outer peripheral surface; 40-blades; 44-a cylindrical portion; 46-an interior space; 48-upper end.

Detailed Description

Some embodiments of the invention are described below with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the constituent members described as the embodiments or shown in the drawings do not limit the scope of the present invention to these, and are merely illustrative examples.

For example, expressions such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "central", "concentric", or "coaxial" which indicate relative or absolute arrangements indicate not only such arrangements as strict ones but also relative displacements in terms of tolerances or angles or distances that can achieve the same degree of functionality.

For example, expressions such as "identical", "equal", and "homogeneous" indicating that objects are in an equal state mean not only an exactly equal state but also a state in which there is a tolerance or a difference in the degree to which the same function can be obtained.

For example, the expression "square" or "cylindrical" indicates not only a shape strictly geometrically including a square shape or a cylindrical shape but also a shape including a concave and convex portion, a chamfered portion, and the like within a range in which the same effect can be obtained.

On the other hand, the expression "present", "having", "provided", "including", or "having" one constituent element is not an exclusive expression that excludes the presence of other constituent elements.

Fig. 1 is a schematic partial cut-away sectional view of a vacuum pump 2 of one embodiment. The illustrated exemplary vacuum pump 2 is an electric vacuum pump for making a negative pressure in a negative pressure chamber of a brake booster (vacuum booster (マスターバック)) in a vehicle such as an automobile. In the following, the terms "upper" and "lower" indicate "upper" and "lower" in a state where the vacuum pump 2 is installed in the vehicle.

As shown in fig. 1, the vacuum pump 2 includes a movable portion 4 for transporting gas, and a pump housing 10 that houses the movable portion 4. The pump housing 10 forms: a pump chamber 5 in which the movable portion 4 is disposed, an intake passage 6 for introducing gas into the pump chamber 5, and an exhaust passage 8 for introducing gas from the pump chamber 5 to the outside. The movable section 4 is configured to be driven by a motor 66 as a driving device to suck gas into the pump chamber 5 and discharge gas from the pump chamber 5.

The exhaust passage 8 includes: an muffling chamber 12 (first muffling chamber) which is an expansion type muffler through which the gas discharged from the pump chamber 5 passes, and an exhaust port 14 which is open to the atmosphere and which discharges the gas passing through the muffling chamber 12 to the outside. The muffling chamber 12 is disposed above the pump chamber 5. The pump housing 10 includes a cylindrical portion 44 protruding upward in the muffling chamber 12, and is configured to allow gas discharged from the pump chamber 5 to flow into the muffling chamber 12 through an internal space 46 of the cylindrical portion 44.

In the illustrated exemplary embodiment, the pump housing 10 further includes a muffling chamber 24 (second muffling chamber) as an expansion-type muffler below the muffling chamber 12, and the muffling chamber 24 and the muffling chamber 12 communicate with each other through an internal space 46 of the chimney-shaped cylindrical portion 44. The cross-sectional shapes of the outer and inner peripheral surfaces of the cylindrical portion 44 are formed in, for example, circular shapes. The gas discharged from the pump chamber 5 passes through the muffling chamber 24, flows into the muffling chamber 12 through the internal space 46 of the cylindrical portion 44, and is discharged from the exhaust port 14.

According to this configuration, as shown in fig. 2, even if the liquid enters the muffling chamber 12 from the exhaust port 14, the liquid can be prevented from accumulating in the muffling chamber 12 and flowing into the internal space 46 of the cylindrical portion 44 before the liquid surface S1 reaches the upper end 48 of the cylindrical portion 44 in the muffling chamber 12. Therefore, the liquid entering from the exhaust port 14 can be prevented from flowing from the muffling chamber 12 to the pump chamber 5 (the muffling chamber 24 in the illustrated embodiment), and the liquid can be prevented from affecting the operation of the movable portion 4. Therefore, the resistance to the liquid entering from the exhaust port 14 can be improved without affecting the size of the vacuum pump 2. Further, since the liquid accumulated in the muffling chamber 12 is discharged from the exhaust port 14 by the exhaust pressure at the time of operating the vacuum pump 2, the influence of the liquid on the operation of the movable portion 4 can be effectively suppressed.

In some embodiments, for example, as shown in fig. 1, the movable portion 4 includes: a rotor 38 disposed in the pump chamber 5 and having a plurality of slits 36 formed in an outer peripheral surface 39; and a plurality of blades 40 respectively disposed at the plurality of slits 36. The pump chamber 5 includes a cam surface 42 facing the outer peripheral surface 39 of the rotor 38.

In this vane type vacuum pump, the rotor 38 coupled to a shaft (not shown) of the motor 66 is rotated by the motor 66, and the vane 40 moves outward in the radial direction of the rotor 38 along the slit 36 of the rotor 38 by a centrifugal force, and the tip end portion 13 of the vane 40 slides on the cam surface 42. Therefore, when the liquid enters the pump chamber 5 through the discharge port 14, the liquid adheres to the surface of the vane 40, and the vane 40 is difficult to move smoothly along the slit 36, and the pump function cannot be stably performed.

In this regard, according to the vacuum pump 2, since the liquid entering from the exhaust port 14 can be suppressed from flowing into the pump chamber 5 as described above, the vane vacuum pump can be efficiently operated stably.

In some embodiments, for example, as shown in fig. 1, the pump housing 10 comprises: a pump housing body 16 that houses the movable portion 4; and a pump cover 18 that is provided separately from the pump housing main body 16 and covers the upper side of the movable portion 4. The upper surface of the pump cover 18 forms the bottom surface 22 of the muffling chamber 12, and the pump cover 18 functions as a first member that forms the bottom surface 22 of the muffling chamber 12. The cylindrical portion 44 protrudes upward from the bottom surface 22 of the muffling chamber 12, and the cylindrical portion 44 and the pump cover 18 are formed integrally of the same material. That is, the cylindrical portion 44 and the pump cover 18 are formed of the same material as one inseparable member.

According to this configuration, since the pump cover 18 constituting the bottom surface 22 of the muffling chamber 12 and the cylindrical portion 44 are formed integrally of the same material, the number of components can be suppressed from increasing as compared with the case where a dedicated component for preventing liquid from entering from the exhaust port 14 is provided, and the influence of the liquid entering from the exhaust port 14 on the operation of the movable portion 4 can be suppressed.

In some embodiments, for example, as shown in fig. 2, the upper end 48 of the cylindrical portion 44 is located higher than the upper end 20 of the exhaust port 14. This effectively prevents the liquid entering the muffling chamber 12 through the exhaust port 14 from flowing into the internal space 46 of the cylindrical portion 44.

In some embodiments, for example, as shown in fig. 2, the muffling chamber 24 is disposed below the muffling chamber 12, and the bottom surface 26 of the muffling chamber 24 is disposed below the bottom surface 27 (see fig. 1) of the pump chamber 5.

According to this configuration, as shown in fig. 3, when the entire vacuum pump 2 sinks into the liquid, the liquid that has entered the muffling chamber 12 from the exhaust port 14 is accumulated in the muffling chamber 12 before the liquid surface S1 reaches the upper end 48 of the cylindrical portion 44, and then flows into the cylindrical portion 44 to start accumulating in the muffling chamber 24. Here, since the bottom surface 26 of the muffling chamber 24 is provided below the bottom surface 27 of the pump chamber 5, the liquid can be prevented from flowing into the pump chamber 5 until the liquid surface S2 of the muffling chamber 24 reaches above the bottom surface 27 of the pump chamber 5. Therefore, even if the entire vacuum pump 2 sinks into the liquid, the liquid can be prevented from flowing into the pump chamber 5 and affecting the operation of the movable portion 4 until a certain time elapses.

In some embodiments, for example, as shown in fig. 4, the bottom surface 22 of the muffling chamber 12 includes a tapered surface 28 that slopes in a downward manner as it approaches the exhaust port 14.

According to this configuration, since the liquid in the muffling chamber 12 flows toward the exhaust port 14 due to the inclination of the tapered surface 28, the discharge of the liquid in the muffling chamber 12 from the exhaust port 14 can be promoted. This can suppress the rise of the liquid level in the muffling chamber 12. Therefore, the inflow of liquid into the internal space 46 of the cylindrical portion 44 can be suppressed, and the influence of the liquid entering from the exhaust port 14 on the operation of the movable portion 4 can be suppressed.

In some embodiments, for example, as shown in fig. 5, the bottom surface 22 of the muffling chamber 12 comprises: the first bottom surface portion 30, and the second bottom surface portion 34 which is adjacent to the first bottom surface portion 30 via the stepped surface 31 and is formed as a support surface for the screw 32 (fastening member) at a position higher than the first bottom surface portion 30. In the illustrated exemplary embodiment, the screw 32 is configured to fasten the pump cover 18 to the pump housing main body 16.

According to this configuration, since the second bottom surface portion 34 formed as a bearing surface for the screw 32 is located at a higher position than the first bottom surface portion 30, the screw 32 is less likely to be immersed in water, and corrosion of the screw 32 can be suppressed.

The present invention is not limited to the above-described embodiments, and includes embodiments in which modifications are made to the above-described embodiments, and embodiments in which these embodiments are appropriately combined.

For example, in the above-described embodiment, the vacuum pump including two muffling chambers is exemplified, but the number of muffling chambers is not limited thereto, and may be, for example, one.

The number of the cylindrical portions is not limited to one, and may be two or more. For example, in the above-described embodiment, two or more cylindrical portions 44 protruding from the bottom surface 22 of the muffling chamber 12 may be provided, and the muffling chamber 12 and the muffling chamber 24 may communicate with each other through the respective cylindrical portions 44.

The cross-sectional shapes of the inner and outer circumferential surfaces of the cylindrical portion 44 may not be circular. Further, the outer peripheral surface of the cylindrical portion 44 may be connected to the side wall of the first muffling chamber 12.

In the above-described embodiment, the rotary vane pump was described as an example of the vacuum pump, but the vacuum pump may be, for example, a piston type pump or a diaphragm type pump. When the vacuum pump is a vane pump, the vacuum pump may be a balanced vane pump or an unbalanced vane pump.

Claims

1. A vacuum pump is provided with:

a pump housing that forms a pump chamber, a first muffling chamber through which gas discharged from the pump chamber passes, and an exhaust port for discharging the gas that has passed through the first muffling chamber to the outside; and

a movable portion for sucking gas into the pump chamber and discharging gas from the pump chamber,

the pump housing includes a cylindrical portion protruding upward in the first muffler chamber, and is configured to allow gas discharged from the pump chamber to flow into the first muffler chamber through an internal space of the cylindrical portion,

the pump housing includes:

a pump housing body that houses the movable portion; and

a pump cover which is provided separately from the pump housing main body and covers the upper side of the movable part,

the pump cover has an upper surface forming a bottom surface of the first muffling chamber and functions as a first member constituting the bottom surface of the first muffling chamber,

the cylindrical portion protrudes upward from a bottom surface of the first muffling chamber,

the pump cover as the first member and the cylindrical portion are formed integrally of the same material.

2. A vacuum pump according to claim 1,

an upper end of the cylindrical portion is located higher than an upper end of the exhaust port.

3. A vacuum pump according to claim 1 or 2,

the pump housing forms a second muffling chamber through which gas discharged from the pump chamber passes and which is disposed below the first muffling chamber,

the bottom surface of the second muffling chamber is disposed below the bottom surface of the pump chamber,

the first muffling chamber and the second muffling chamber are configured to communicate with each other through an internal space of the cylindrical portion.

4. A vacuum pump according to claim 1 or 2,

the bottom surface of the first muffling chamber includes a tapered surface inclined downward as approaching the exhaust port.

5. Vacuum pump according to claim 1 or 2,

the bottom surface of the first muffling chamber comprises:

a first bottom surface portion; and

and a second bottom surface portion which is adjacent to the first bottom surface portion and is formed as a support surface for the fastening member at a position higher than the first bottom surface portion.

6. Vacuum pump according to claim 1 or 2,

the movable portion includes:

a rotor disposed in the pump chamber and having a plurality of slits formed in an outer circumferential surface thereof; and

and a plurality of blades respectively disposed at the plurality of slits.