JP2024179418A - Vacuum Pump - Google Patents

Abstract

To provide a vacuum pump capable of making sealing of an exhaust passage compatible with compactification.SOLUTION: A vacuum pump 1 comprises a casing 2 including a pump chamber 10, an intake passage 20 and an exhaust passage 30 communicating to the pump chamber 10. The casing 2 includes: a first component 100 including a projection 102 in which a first exhaust passage 32 in the exhaust passage 30 is formed; and a second component 200 including a fitting hole 202 which forms a second exhaust passage 34 communicating to the first exhaust passage 32 in the exhaust passage 30 and to which the projection 102 can be fitted, and an outer peripheral edge 210 which is provided at an outer peripheral side of the fitting hole 202, while protruding toward the first component 100. The vacuum pump 1 further comprises a seal member 300, which is held between the first component 100 and the second component 200 so as to be positioned between the projection 102 of the first component 100 and the outer peripheral edge 210 of the second component 200 in a radial direction, for sealing the exhaust passage 30 including the first exhaust passage 32 and the second exhaust passage 34.SELECTED DRAWING: Figure 4

Description

This disclosure relates to a vacuum pump.

2. Description of the Related Art Vacuum pumps are conventionally known for maintaining the interior of a container at a pressure below atmospheric pressure.
For example, Patent Document 1 describes a vacuum pump for maintaining a negative pressure chamber of a brake booster in a vehicle such as an automobile at or below atmospheric pressure.

Furthermore, in Patent Document 2, in consideration of the possibility that liquid such as water splashes may adhere to the exhaust port depending on the usage environment, a vacuum pump is described that can prevent liquid from getting on the exhaust port while suppressing an increase in the number of parts.

JP 2014-25413 A JP 2020-76336 A

Generally, the casing of a vacuum pump is formed by assembling a plurality of parts.
In this case, depending on the layout of the internal flow path of the casing, the exhaust passage of the vacuum pump may be divided into multiple sections, and the exhaust passages of each section may be distributed to multiple casing parts. By assembling the multiple casing parts, the exhaust passages of adjacent sections are connected to each other at the joint surfaces between the casing parts.

As described above, when the exhaust passage divided into a plurality of sections is provided in a distributed manner among a plurality of casing parts, it is necessary to provide a seal member for sealing the exhaust passage on the joint surfaces between the casing parts.
However, ensuring space for installing a seal member on the joint surfaces between the casing parts can be an obstacle to making the vacuum pump more compact.

In view of the above, at least some embodiments of the present invention aim to provide a vacuum pump that is capable of sealing the exhaust passage while being compact.

A vacuum pump according to at least some embodiments of the present invention comprises:
The pump includes a casing including a pump chamber and an intake passage and an exhaust passage communicating with the pump chamber,
The casing is
a first component having a protrusion in which a first exhaust passage is formed;
a second component that defines a second exhaust passage that is in communication with the first exhaust passage among the exhaust passages, the second component having a fitting hole into which the protrusion can be fitted, and an outer circumferential edge portion that is provided on an outer circumferential side of the fitting hole and protrudes toward the first component;
Including,
The engine further includes a sealing member that is held between the first part and the second part so as to be positioned radially between the convex portion of the first part and the outer peripheral edge portion of the second part, for sealing the exhaust passage including the first exhaust passage and the second exhaust passage.

According to at least some embodiments of the present invention, the seal member is held between the first and second parts so as to be positioned radially between the protrusion of the first part and the outer peripheral edge of the second part, so there is no need to form a groove in either the first or second part to accommodate the seal member. This makes it possible to make the vacuum pump more compact.

FIG. 2 is a schematic diagram illustrating an internal flow path of a vacuum pump according to an embodiment. FIG. 13 is a diagram illustrating an internal flow path of a vacuum pump according to another embodiment. FIG. 13 is a schematic diagram illustrating an internal flow path of a vacuum pump according to yet another embodiment. 2 is a partial cross-sectional view of a casing of a vacuum pump according to an embodiment, showing a structure around an exhaust passage. FIG. FIG. 5 is a diagram showing a state before assembly of a casing of the vacuum pump shown in FIG. 4. 13 is a partial cross-sectional view of a casing of a vacuum pump according to another embodiment, showing a structure around an exhaust passage. FIG. FIG. 7 is a diagram showing a state before assembly of a casing of the vacuum pump shown in FIG. 6 . FIG. 4 is a diagram showing a configuration of an extension tube in a vacuum pump according to an embodiment. 1 is an exploded perspective view showing an overall structure of a vacuum pump according to an embodiment of the present invention;

Below, several embodiments of the present invention will be described with reference to the attached drawings. However, the dimensions, materials, shapes, relative positions, etc. of the components described as the embodiments or shown in the drawings are not intended to limit the scope of the present invention and are merely illustrative examples.

Fig. 1 is a schematic diagram showing an internal flow path of a vacuum pump 1A according to one embodiment, Fig. 2 is a schematic diagram showing an internal flow path of a vacuum pump 1B according to another embodiment, and Fig. 3 is a schematic diagram showing an internal flow path of a vacuum pump 1C according to yet another embodiment.
Hereinafter, vacuum pumps according to several embodiments including vacuum pumps 1A, 1B, and 1C may be collectively referred to as vacuum pump 1. The vacuum pump 1 is not limited to vacuum pumps 1A, 1B, and 1C, and also includes vacuum pumps according to other embodiments not shown.

In some embodiments, as shown in Figures 1 to 3, the vacuum pump 1 includes a pump chamber 10, an intake passage 20 communicating with the pump chamber 10, and an exhaust passage 30 as internal flow paths in the casing of the vacuum pump 1.

The pump chamber 10 has an intake port 12 and an exhaust port 14 .
When the vacuum pump 1 is a positive displacement vacuum pump, the vacuum pump 1 includes a gas transfer section 40 in the pump chamber 10. The gas transfer section 40 is configured to periodically transfer a predetermined volume of gas from the inlet 12 to the outlet 14.

The gas transfer section 40 includes a movable section 42 that can have various configurations depending on the type of the vacuum pump 1. The movable section 42 is configured to be able to transfer gas by reciprocating or rotating.
For example, if the vacuum pump 1 is a reciprocating pump, the gas transfer unit 40 includes a moving part 42 such as a diaphragm or a piston. In other embodiments, the vacuum pump 1 is a rotary pump and includes rotors of various shapes as the moving part 42 of the gas transfer unit 40.

The intake port 12 of the pump chamber 10 is connected to the intake passage 20, and the gas flowing through the intake passage 20 is taken into the pump chamber 10 via the intake port 12. On the other hand, the discharge port 14 of the pump chamber 10 is connected to the exhaust passage 30, and the gas discharged from the pump chamber 10 is released to the atmosphere via the discharge port 14 and the exhaust passage 30.

The exhaust passage 30 may be a flow path through which the gas discharged from the pump chamber 10 flows, and the specific configuration of the exhaust passage 30 is not particularly limited.
1 and 2, the exhaust passage 30 directly communicates with the pump chamber 10 via the discharge port 14. In the embodiment shown in Fig. 3, one or more chambers (50, 60) are provided between the pump chamber 10 and the exhaust passage 30 in the gas flow direction, and the exhaust passage 30 communicates with the pump chamber 10 via the one or more chambers (50, 60) and the discharge port 14.

The one or more chambers (50, 60) provided between the pump chamber 10 and the exhaust passage 30 may include sound-absorbing chambers 50, 60.
3, the first silencing chamber 50 is located below and to the side of the pump chamber 10, and receives gas discharged from the pump chamber 10 via the discharge port 14. The first silencing chamber 50 communicates with a second silencing chamber 60 located above the pump chamber 10 via a communication passage 62. The second silencing chamber 60 communicates with the exhaust passage 30, and the second silencing chamber 60 guides the gas that has passed through the first silencing chamber 50 to the exhaust passage 30.

1 and 3, when the exhaust passage 30 serving as the internal flow path of the vacuum pump 1 is a downward flow path, an extension pipe 70 may be connected to the exhaust passage 30 in order to prevent water from entering the vacuum pump 1 from the exhaust passage 30. The extension pipe 70 has an outlet 71 at a position higher than the downstream end of the exhaust passage 30, and communicates with the atmosphere at the outlet 71.
2, the exhaust passage 30 is an upward flow path, and the exhaust passage 30 communicates directly with the atmosphere without passing through the extension pipe 70. When the exhaust passage 30 is an upward flow path, a cover (not shown) may be provided at the open end of the exhaust passage 30 to prevent foreign matter from entering the exhaust passage 30.

The casing of the vacuum pump 1 having the above-mentioned internal flow path may be formed by assembling multiple parts. In this case, depending on the layout of the internal flow path of the casing, the exhaust passage 30 may be divided into multiple sections, and each section of the exhaust passage 30 may be distributed among multiple casing parts. Adjacent sections of the exhaust passage 30 are connected to each other at the joint surfaces between the casing parts by assembling multiple casing parts.

Hereinafter, with reference to Figs. 4 to 7, a description will be given of the casing of the vacuum pump 1 in which the sections of the exhaust passage 30 are distributed among a plurality of casing parts.
Fig. 4 is a partial cross-sectional view of a casing of a vacuum pump according to one embodiment, showing a structure around an exhaust passage 30. Fig. 5 is a view showing a state before assembly of the casing of the vacuum pump shown in Fig. 4.
Fig. 6 is a partial cross-sectional view of a casing of a vacuum pump according to another embodiment, showing the structure around an exhaust passage 30. Fig. 7 is a view showing the state before assembly of the casing of the vacuum pump shown in Fig. 6.

In some embodiments, as shown in Figures 4 and 6, the casing 2 (2A, 2B) of the vacuum pump 1 includes a first part 100 in which the first exhaust passage 32 of the exhaust passage 30 is formed, and a second part 200 in which the second exhaust passage 34 of the exhaust passage 30 is formed.
Here, the first exhaust passage 32 and the second exhaust passage 34 correspond to two flow path sections of the exhaust passage 30 provided in a distributed manner in the first part 100 and the second part 200. The number of parts of the casing 2 and the sections of the exhaust passage 30 are not particularly limited, and the exhaust passage 30 divided into three or more sections may be provided in a distributed manner in three or more parts. In this case, the first exhaust passage 32 and the second exhaust passage 34 provided in the first part 100 and the second part 200, respectively, may be a pair of adjacent sections among the three or more sections of the exhaust passage 30.

4 and 6, the first exhaust passage 32 formed in the first component 100 is located upstream of the second exhaust passage 34 formed in the second component 200 in the gas flow direction. That is, the gas discharged from the pump chamber 10 flows through the first exhaust passage 32 and then the second exhaust passage 34, and is finally released into the atmosphere. Note that the first component 100 may be formed with a second silencing chamber 60 (see FIG. 3) located upstream of the first exhaust passage 32.
In another embodiment, the second exhaust passage 34 of the second part 200 is located upstream of the first exhaust passage 32 of the first part 100 in the gas flow direction.

The first part 100 has a protruding part 102 in which the first exhaust passage 32 is formed. The protruding part 102 is provided to protrude from a surface of the first part 100 (the surface facing the second part 200) along the extension direction of the first exhaust passage 32. The first exhaust passage 32 is formed by a through hole 104 provided in the protruding part 102. The through hole 104 opens to a top surface 103 of the protruding part 102, and forms a flow passage end 33 of the first exhaust passage 32.
4 and 6, the protrusion 102 is cylindrical and has a circumferential outer circumferential surface 106. In addition to the protrusion 102, the first part 100 includes a flat surface 108 that faces the second part 200 on the outer circumferential side of the outer circumferential surface 106 of the protrusion 102. The protrusion 102 protrudes from the flat surface 108 toward the second part 200.

The second part 200 includes a fitting hole 202 that forms the second exhaust passage 34, and an outer peripheral edge portion 210 that is located on the outer peripheral side of the open end of the fitting hole 202. The outer peripheral edge portion 210 is provided so as to protrude toward the first part 100 from the surface of the second part 200 that faces the first part 100.

The fitting hole 202 of the second part 200 has an inner diameter corresponding to the outer diameter of the convex portion 102 of the first part 100, so that the convex portion 102 can be fitted into the fitting hole 202. Here, the "inner diameter corresponding to" the outer diameter of the convex portion 102 means an inner diameter that is the same as the diameter of the outer circumferential surface 106 of the convex portion 102, or an inner diameter that is slightly larger than the diameter of the outer circumferential surface 106 of the convex portion 102.
The relative positional relationship between the first part 100 and the second part 200 in the casing 2 is not particularly limited, but the first part 100 may be located above the second part 200 as shown in Figures 4 to 7. In this case, the convex part 102 of the first part 100 is provided so as to protrude downward toward the second part 200 and is fitted into the fitting hole 202.

When the convex portion 102 of the first part 100 is engaged with the mating hole 202 of the second part 200, the flow path end 33 of the first exhaust passage 32 is positioned within the mating hole 202 that forms the second exhaust passage 34, and the first exhaust passage 32 and the second exhaust passage 34 are connected to each other.
4 to 7, an extension pipe 70 may be connected to the end of the fitting hole 202 opposite to the fitting portion with the protrusion 102. In this case, the gas that has passed through the first exhaust passage 32 and the second exhaust passage 34 is released to the atmosphere via the extension pipe 70.

In the embodiment shown in Figures 4 to 7, the outer peripheral edge portion 210 protrudes toward the first part 100 on the outer peripheral side of the fitting hole 202 and abuts against the flat surface 108 of the first part 100. In other words, the abutment surface 212 of the second part 200 against the flat surface 108 of the first part 100 is the top surface of the outer peripheral edge portion 210. The abutment surface 212 of the second part 200 may be provided in a substantially annular shape surrounding the fitting hole 202 as a flat surface parallel to the flat surface 108 of the first part 100.

In some embodiments, the vacuum pump 1 includes a seal member 300 held between the first part 100 and the second part 200, as shown in Figures 4 and 6.

The seal member 300 may be an annular seal made of an elastic polymer compound (elastomer).
4-7, the seal member 300 is an O-ring having a circular cross-section. In other embodiments, the seal member 300 is an annular seal having a non-circular cross-sectional shape. Examples of annular seals having a non-circular cross-section include X-rings and D-rings.

The seal member 300 is located between the protrusion 102 of the first part 100 and the outer peripheral edge portion 210 of the second part 200 in the radial direction of the annular seal member 300. In other words, the seal member 300 is provided between the radial position of the outer peripheral surface 106 of the protrusion 102 and the radial position of the inner circumferential surface of the outer peripheral edge portion 210, and surrounds the protrusion 102.
Additionally, the seal member 300 is located axially closer to the first component 100 than the top surface 103 of the protrusion 102 and the flow passage end 33 of the first exhaust passage 32 .

When the first part 100 is assembled to the second part 200 , the seal member 300 is crushed and deformed by the first part 100 and the second part 200 , thereby sealing the exhaust passage 30 including the first exhaust passage 32 and the second exhaust passage 34 .
In the example shown in Fig. 5, the thickness t of the seal member 300A before deformation is greater than the height of the outer peripheral edge portion 210 (the distance from the bottom surface 222 to the abutment surface 212). Similarly, as shown in Fig. 7, the width w of the seal member 300B before deformation is smaller than the radial gap between the outer peripheral surface 106 of the protruding portion 102 that contacts the seal member 300B and the inner wall surface of the fitting hole 202. For this reason, when the first part 100 is assembled to the second part 200 so that the protruding portion 102 fits into the fitting hole 202, the seal member 300 (300A, 300B) is crushed in the axial or radial direction as shown in Figs. 4 and 6.

In some embodiments, such as the casing 2A shown in Figures 4 and 5, the second part 200 has a recess 220 located radially inside the outer circumferential edge portion 210, and the seal member 300A is housed in the recess 220.
Specifically, the recess 220 is provided radially inward of the outer peripheral edge portion 210 and radially outward of the fitting hole 202, so as to be recessed with respect to the outer peripheral edge portion 210. A bottom surface 222 of the recess 220 is located inside the second part 200 relative to the abutment surface 212 of the outer peripheral edge portion 210 in the axial direction of the annular seal member 300A, and faces the flat surface 108 of the first part 100. The fitting hole 202 opens in the bottom surface 222 of the recess 220. The seal member 300A is held between the first part 100 and the second part 200 in a state where it is sandwiched between the flat surface 108 of the first part 100 and the bottom surface 222 of the recess 220 of the second part 200 in the axial direction.

When assembling the casing 2A, as shown in FIG. 5, the first part 100 is assembled to the second part 200 so that the protrusion 102 fits into the fitting hole 202 with the seal member 300A placed on the bottom surface 222 of the recess 220. The seal member 300A before deformation and the recess 220 satisfy the relationship (ds-di)>(do-ds-2×w). That is, the radial distance from the inner peripheral end of the seal member 300A before deformation to the opening edge of the fitting hole 202 is greater than the radial distance from the outer peripheral end of the seal member 300A before deformation to the inner peripheral surface of the outer peripheral edge portion 210. Here, ds is the inner diameter of the seal member 300A before deformation, w is the width of the cross section of the seal member 300A before deformation, and di and do are the inner diameter and outer diameter of the bottom surface 222 of the recess 220, respectively. In the example shown in FIG. 5, (do-ds-2×w)>0 is further satisfied.
By satisfying the above relationship, after assembly of the casing 2A, as shown in FIG. 4, a radial gap is secured between the outer peripheral surface 106 of the convex portion 102 of the first part 100 that is fitted into the fitting hole 202 and the sealing member 300A, while the sealing member 300A is in close contact with the inner peripheral surface of the outer peripheral edge portion 210.
The ratio of the radial distances (ds-di)/(do-ds-2×w) between the seal member 300A before deformation and the recess 220 may be 2 or more, or may be 3 or more.

In the exemplary embodiment shown in FIGS. 4 and 5, the convex portion 102 of the first component 100 has an outer peripheral edge 113 of the top surface 103 chamfered to form a tapered shape.
Therefore, when the first part 100 is assembled to the second part 200 , the tapered outer peripheral edge 113 of the first part 100 serves to guide the protrusion 102 into the fitting hole 202 .

In another embodiment, as in the casing 2B shown in Figures 6 and 7, the outer peripheral surface 106 of the convex portion 102 of the first part 100 has a step 107, and the sealing member 300B is held between the portion of the convex portion 102 that is closer to the tip side (top surface 103 side) than the step 107 and the mating hole 202 of the second part 200.
Specifically, outer peripheral surface 106 of protrusion 102 of casing 2B has a base end region located on the base end side of step 107 and having an outer diameter corresponding to the inner diameter of fitting hole 202, and a tip end region located on the tip end side of step 107 and having a smaller diameter than the base end region. In casing 2B, the inner diameter of outer peripheral edge portion 210 matches the inner diameter of fitting hole 202, and the inner peripheral surface of outer peripheral edge portion 210 is continuous with the inner wall surface of fitting hole 202 in the axial direction without any step. In casing 2B after assembly, seal member 300B is held in the radial gap between the tip end region of outer peripheral surface 106 of protrusion 102 and the inner wall surface of fitting hole 202.

7, when assembling the casing 2B, with the seal member 300B attached to the tip region of the protrusion 102 of the first part 100, the first part 100 is assembled to the second part 200 so that the protrusion 102 fits into the fitting hole 202. The seal member 300B, the protrusion 102, and the fitting hole 202 before deformation satisfy the relationship (d1+2×w)>d2, where d1 is the outer diameter of the tip region of the outer circumferential surface 106 of the protrusion 102, d2 is the inner diameter of the fitting hole 202, and w is the cross-sectional width of the seal member 300B before deformation.
By satisfying the above relationship, after assembly of the casing 2B, as shown in Figure 6, the sealing member 300B adheres closely to the inner wall surface of the fitting hole 202, the tip region of the outer circumferential surface 106 of the convex portion 102, and the step surface of the step 107 of the convex portion 102.

In some embodiments, as shown in Figures 4 to 7, an extension pipe 70 (see Figures 1 and 3) is connected to the second part 200 to guide the downward exhaust flow that passes through the first exhaust passage 32 and then the second exhaust passage 34 to a higher position.

FIG. 8 is a diagram showing a configuration of an extension tube in a vacuum pump according to an embodiment.
As shown in the figure, the extension pipe 70 is attached to the second part 200 so as to communicate with the exhaust passage 30 (second exhaust passage 34), and is connected to the end of the fitting hole 202 on the opposite side to the fitting part with the protrusion 102. The extension pipe 70 includes an upstream part 72 extending downward from the second part 200, and a downstream part 74 located downstream of the upstream part 72. The downstream part 74 of the extension pipe 70 turns back at a bottom 76 of the extension pipe 70, and extends upward to an outlet 71 of the extension pipe 70 located higher than the second part 200. As shown in FIG. 8, the outlet 71 of the extension pipe 70 may be located higher than the first part 100.
The exhaust flow that has passed through the exhaust passage 30 (second exhaust passage 34 ) flows sequentially through an upstream portion 72 and a downstream portion 74 of the extension pipe 70 , and is then released into the atmosphere from an outlet 71 of the extension pipe 70 .

8, the extension tube 70 includes a nipple 73 press-fitted into the fitting hole 202 so as to extend downward from the second part 200, and a U-shaped hose 75 attached to the nipple 73. The hose 75 is connected to the portion of the nipple 73 protruding from the second part 200 using a band 78.
The nipple 73 forms the upstream portion 72 of the extension tube 70, whereas the hose 75 forms the bottom 76 and downstream portion 74 of the extension tube 70.

Next, a specific example of the overall structure of the vacuum pump 1 according to the above-described embodiment will be described.
9 is an exploded perspective view showing an overall structure of a vacuum pump 1 according to one embodiment. The vacuum pump 1 may be, for example, an electric vacuum pump for creating a negative pressure in a negative pressure chamber of a brake booster (master back) in a vehicle such as an automobile.
In the following, "upper" and "lower" refer to the "upper" and "lower" in the state in which the vacuum pump 1 is installed in the vehicle.

The vacuum pump 1 includes a casing 2 and a movable part 42 of a gas transfer part 40 provided within the casing 2 .
9 , in some embodiments, the movable part 42 is a rotor 43 rotatably provided within the casing 2. The rotor 43 is driven by a motor M provided below the casing 2 and rotates around a central axis O.

9, the casing 2 has a pump chamber 10 in which a rotor 43 serving as a movable part 42 is housed. The pump chamber 10 is defined by a cam surface 11 that is a part of the inner wall surface of the casing 2. The cam surface 11 is defined by a non-circular (e.g., elliptical) outline.
On the other hand, the rotor 43 has an outer peripheral surface 44 defined by a circular contour centered at point O. A plurality of slits 45 are formed in the outer peripheral surface 44. Each slit 45 is provided with a vane 46 that divides the pump chamber 10 into a plurality of compartments.

In the example shown in FIG. 9, the casing 2 includes a casing body 3 having a recess that forms the bottom and side surfaces of the pump chamber 10 in which the rotor 43 is housed, and a pump cover 4 that forms the top surface of the pump chamber 10. The pump cover 4 forms the pump chamber 10 together with the casing body 3 by closing the opening of the recess in the casing body 3 that forms the bottom and side surfaces of the pump chamber 10. A top cover 5 that covers the pump cover 4 is provided above the pump cover 4. Meanwhile, a bottom cover 6 that covers the underside of the casing body 3 is provided between the casing body 3 and the motor M.

A seal member 90 is provided between the top cover 5 and the pump cover 4. The seal member 90 includes an inner seal portion 94, an outer seal portion 96 that surrounds the inner seal portion 94, and a connection portion 95 that connects the inner seal portion 94 and the outer seal portion 96 to each other.

When the top cover 5 is fastened to the pump cover 4, the seal member 90 elastically deforms so as to be crushed within the seal groove 91, thereby closing the gap between the pump cover 4 and the top cover 5. As a result, a second silencing chamber 60 (see FIG. 3 ) is formed between the inner seal portion 94 and the outer seal portion 96.
The second silencing chamber 60 is formed by the pump cover 4 and the top cover 5 above the pump chamber 10 on the opposite side to the pump chamber 10 with the pump cover 4 in between. The second silencing chamber 60 communicates with the first silencing chamber 50 formed in the casing body 3 via two openings 63 provided in the pump cover 4 and two communication holes 64 formed in the casing body 3. In other words, the two sets of openings 63 and communication holes 64 form two communication passages 62 (see FIG. 3 ) that communicate between the first silencing chamber 50 and the second silencing chamber 60.

The bottom cover 6 has an intake port 21 which is an inlet for the gas flow toward the pump chamber 10 .
The intake port 21 is led to an intake chamber 24 formed between the pump cover 4 and the top cover 5 via a communication passage 22 provided in the casing body 3 and a communication passage 23 provided in the pump cover 4. The communication passage 23 penetrates the pump cover 4, and the gas that has passed through the communication passage 22 provided in the casing body 3 flows through the communication passage 23 into the intake chamber 24 formed above the pump cover 4.

The intake chamber 24 is fluidly isolated from the second silencing chamber 60 around the partition wall portion 25 by the partition wall portion 25 and an inner seal portion 94 provided in the pump cover 4 .
The intake chamber 24 communicates with the internal space of the pump chamber 10 via the intake ports 12 (12A, 12B) of the pump chamber 10 provided in the pump cover 4. The pair of intake ports 12 (12A, 12B) are located on opposite sides of the central axis O of the rotor 43. Therefore, the intake chamber 24 extends from the communication passage 23 toward the opposite side of the central axis O along the radial direction of the rotor 43 so as to pass through the positions of the pair of intake ports 12 (12A, 12B).

In this way, the gas taken in through the intake port 21 passes through the communication passage 22, the communication passage 23, and the intake chamber 24 in order, and then flows into the pump chamber 10 through the pair of intake ports 12 (12A, 12B). In other words, the intake passage 20 (see Figures 1 to 3) for taking in gas into the pump chamber 10 includes the communication passage 22, the communication passage 23, and the intake chamber 24.

An outlet port 14 for the pump chamber 10 is provided in the wall surface of the casing body 3 that constitutes the bottom surface of the pump chamber 10. Although only one outlet port 14 is shown in Fig. 9, another outlet port 14 (not shown) is provided at a circumferential position on the opposite side across the central axis O.
The gas flowing out of the pump chamber 10 through the pair of discharge ports 14 flows into a first silencing chamber 50 (see FIG. 3) formed by the casing body 3 and the bottom cover 6. After passing through the first silencing chamber 50, the gas flows into a second silencing chamber 60 through a communication hole 64 and an opening 63, and is finally released into the atmosphere through an exhaust passage 30 (see FIGS. 1 to 7) and an extension tube 70 which communicate with the second silencing chamber 60.

In the example shown in FIG. 9, the exhaust passage 30 is formed inside the pump cover 4 as the first part 100 and the casing body 3 as the second part 200 so as to be located between the second silencing chamber 60 and the extension pipe 70. The protrusion 102 of the pump cover 4 fits into the fitting hole 202 of the casing body 3, and the first exhaust passage 32 provided inside the protrusion 102 communicates with the second exhaust passage 34 defined by the fitting hole 202, forming the exhaust passage 30 including the first exhaust passage 32 and the second exhaust passage 34. The exhaust passage 30 is sealed by a seal member 300A (see FIGS. 4 and 5) held between the pump cover 4 and the casing body 3. The seal member 300A is accommodated in a recess 220 recessed based on an annular outer peripheral edge portion 210 provided to surround the fitting hole 202 of the casing body 3.

Here, in the embodiment shown in FIG. 9, the pump cover 4 is provided with two openings 63 and a first exhaust passage 32 in the protruding portion 102 so as to penetrate the pump cover 4. The openings 63 are part of a communication passage 62 for communicating the second silencing chamber 60 with the first silencing chamber 50 (see FIG. 3) provided below and to the side of the pump chamber 10. The first exhaust passage 32 is located outside the openings 63 in the radial direction of the rotor 43 based on the central axis O. The outer seal portion 96 and the seal groove 91 of the seal member 90 bulge outward in the radial direction in the vicinity of the first exhaust passage 32 so as to surround the first exhaust passage 32. In order to make the casing 2 compact, it is desirable to suppress the bulging of the outer seal portion 96 and the seal groove 91 outward in the radial direction. On the other hand, if the bulging of the outer seal portion 96 and the seal groove 91 outward in the radial direction is excessively suppressed, it is not possible to secure a space for installing the seal member 300A (a groove for installing the seal member).
In this regard, the seal member 300A can be held radially between the protrusion 102 of the pump cover 4 and the outer peripheral edge 210 of the casing body 3, making it possible to make the casing 2 compact.

In the example shown in FIG. 9, the nipple 73 is press-fitted from below into the fitting hole 202 of the casing body 3 as the second part 200, and a U-shaped hose 75 is attached to the lower end of the nipple 73. The nipple 73 and the hose 75 correspond to the upstream part 72 and downstream part 74, respectively, of the extension pipe 70 described with reference to FIG. 8.

The characteristic configurations of the vacuum pump 1 according to the above-mentioned embodiments can be summarized as follows:

[1] A vacuum pump (1) according to some embodiments,
The pump includes a casing (2) including a pump chamber (10), and an intake passage (20) and an exhaust passage (30) communicating with the pump chamber (10);
The casing (2) is
a first part (100) having a protrusion (102) in which a first exhaust passage (32) of the exhaust passage (30) is formed;
a second component (200) that forms a second exhaust passage (34) that communicates with the first exhaust passage (32) of the exhaust passage (30) and has a fitting hole (202) into which the protrusion (102) can be fitted, and an outer peripheral edge portion (210) that is provided on the outer periphery side of the fitting hole (202) and protrudes toward the first component (100);
Including,
The vacuum pump (1) further includes a seal member (300) that is held between the first part (100) and the second part (200) so as to be positioned radially between the convex portion (102) of the first part (100) and the outer peripheral edge portion (210) of the second part (200), and that seals the exhaust passage (30) including the first exhaust passage (32) and the second exhaust passage (34).

Conventionally, the seal member has generally been installed in a groove for installing the seal member. The groove for installing the seal member is formed between the inner annular convex portion and the outer annular convex portion. Therefore, forming a groove for installing the seal member on the joint surface between the casing parts can be an obstacle to making the vacuum pump more compact.
In this regard, according to the configuration of [1] above, since the seal member (300) is held between the convex portion (102) of the first part (100) and the outer peripheral edge portion (210) of the second part (200) in the radial direction, there is no need to form a groove for installing the seal member in either the first part (100) or the second part (200). Therefore, the vacuum pump (1) can be made more compact.

[2] In some embodiments, in the configuration of [1] above,
The first part (100) is located above the second part (200);
The protrusion (102) of the first component (100) is provided so as to protrude downward toward the second component (200) and is fitted into a fitting hole (202) of the second component (200).

According to the configuration [2] above, when assembling the first part (100) to the second part (200), the visibility of the protrusion (102) and the fitting hole (202) is improved, and the protrusion (102) and the fitting hole (202) can be easily used to position the first part (100) relative to the second part (200).

[3] In some embodiments, in the configuration of [2] above,
The vacuum pump (1) includes an extension pipe (70) attached to the second component (200) so as to communicate with the exhaust passage (30), and connected to an end of the fitting hole (202) on the opposite side to the fitting portion with the protrusion (102);
The extension tube (70) is
an upstream portion (72) extending downwardly from the second part (200);
a downstream portion (74) located downstream of the upstream portion (72) and extending upward to a position higher than the second part (200);
Including,
The extension pipe (70) is configured to guide the exhaust flow that has passed through the first exhaust passage (32) and the second exhaust passage (34) to an outlet (71) of the extension pipe (70) that is located higher than the second component (200).

According to the configuration [3] above, the outlet (71) of the extension pipe (70) communicating with the exhaust passage (30) is provided at a position higher than the second component (200), thereby preventing water from entering the vacuum pump (1) through the exhaust flow path (30). Also, according to the configuration [1] above, the connection portion between the first exhaust passage (32) and the second exhaust passage (34) can be sealed while making the vacuum pump (1) more compact.
In this way, measures to prevent flooding of the vacuum pump (1) can be realized with a simple and compact configuration.

[4] In some embodiments, in the configuration of [3] above,
The extension tube (70) is
a nipple (73) as an upstream portion (72) press-fitted into a fitting hole (202) of the second part (200) so as to extend downward from the second part (200);
a U-shaped hose (75) as a downstream portion (74) attached to a portion of the nipple (73) protruding from the second part (200);
Includes.

According to the configuration of [4] above, by using a nipple (73) press-fitted into the fitting hole (202) of the second part (200) and a hose (75) attached to the nipple (73), an extension pipe (70) having an outlet (71) located higher than the second part (200) can be realized without providing an additional sealing member.

[5] In some embodiments, in any one of the configurations [1] to [4] above,
The casing (2) is
A pump cover (4) as a first part (100);
A casing body (3) as a second part (200);
a top cover (5) that is attached to the pump cover (4) and is located on the opposite side of the pump cover (4) from the casing body (3);
Including,
The pump chamber (10) is formed by the pump cover (4) and the casing body (3) by closing an opening of a recess provided in the casing body (3) with the pump cover (4).
A sound-absorbing chamber (60) that guides the gas discharged from the pump chamber (10) to the first exhaust passage (32) is formed by the pump cover (4) and the top cover (5) above the pump chamber (10) on the opposite side to the pump chamber (10) with the pump cover (4) in between.

In the configuration of [5] above, the pump cover (4) and the casing body (3) correspond to the first part (100) and the second part (200) of the configuration of [1] above, respectively. That is, the first exhaust passage (32) and the second exhaust passage (34) are provided in a distributed manner in the pump cover (4) as the first part (100) and the casing body (3) as the second part (200), and the exhaust passage (30) is sealed by the seal member (300) held between the pump cover (4) and the second part (200). The seal member (300) is held between the convex part (102) of the pump cover (4) and the outer peripheral edge part (210) of the pump casing body (3) in the radial direction, so there is no need to form a groove for installing the seal member in either the pump cover (4) or the casing body (3). Therefore, the vacuum pump (1) can be made compact.

[6] In some embodiments, in any one of the configurations [1] to [5] above,
The first component (100) has a flat surface (108) facing the second component (200) on the outer circumferential side of the protruding portion (102),
The second component (200) has a recess (220) that is recessed with respect to the outer circumferential edge portion (210) on the radially inner side of the outer circumferential edge portion (210),
The fitting hole (202) opens to a bottom surface (222) of the recess (220) facing the flat surface (108) of the first component (100);
The seal member (300A) is held in an axially sandwiched state between the flat surface (108) of the first part (100) and the bottom surface (222) of the second part (200).

According to the configuration of [6] above, a space for accommodating the seal member (300A) can be secured between the outer peripheral surface (106) of the convex portion (102) and the inner peripheral surface of the outer peripheral edge portion (210). Therefore, it is not necessary to form a groove for installing the seal member in either the first part (100) or the second part (200). This allows the vacuum pump (1) to be made more compact.

In some embodiments, in the configuration of [6] above,
The sealing member (300A) is sandwiched between the flat surface (108) of the first part (100) and the bottom surface (222) of the second part (200) in the axial direction, and is arranged with a radial gap between it and the outer peripheral surface (106) of the convex portion (102).

According to the configuration of [7] above, a radial gap is maintained between the outer peripheral surface (106) of the protruding portion (102) and the sealing member (300A), so that when the first part (100) is removed from the second part (200), the sealing member (300A) remains in the recessed portion (220) of the second part (200). This prevents a situation in which the sealing member (300A) cannot be easily removed from the protruding portion (102) of the first part (100) when disassembling the vacuum pump (1).

[8] In some embodiments, in the configuration of [7] above,
The seal member (300A) is configured to be in close contact with the outer peripheral edge portion (210) of the second part (200) while being axially sandwiched between the flat surface (108) of the first part (100) and the bottom surface (222) of the second part (200).

According to the configuration of [8] above, the sealing member (300A) is sandwiched between the flat surface (108) of the first part (100) and the bottom surface (222) of the second part (200) and is also in close contact with the outer periphery (210), so that a high sealing effect can be obtained by the sealing member (300A).

[9] In some embodiments, in any one of the configurations [1] to [5] above,
The sealing member (300B) is held in a radially sandwiched state between the outer peripheral surface (106) of the convex portion (102) of the first part (100) and the inner wall surface of the mating hole (202) that communicates with the inner peripheral surface of the outer peripheral edge portion (210) of the second part (200).

According to the configuration of [9] above, the seal member (300A) is held between the outer peripheral surface (106) of the protrusion (102) and the inner wall surface of the fitting hole (202). Therefore, it is not necessary to form a groove for installing the seal member in either the first part (100) or the second part (200). This makes it possible to make the vacuum pump (1) more compact.

In this specification, expressions expressing relative or absolute configuration, such as "in a certain direction,""along a certain direction,""parallel,""orthogonal,""center,""concentric," or "coaxial," do not only strictly represent such a configuration, but also represent a state in which there is a relative displacement with a tolerance or an angle or distance to the extent that the same function is obtained.
For example, expressions indicating that things are in an equal state, such as "identical,""equal," and "homogeneous," not only indicate a state of strict equality, but also indicate a state in which there is a tolerance or a difference to the extent that the same function is obtained.
Furthermore, in this specification, expressions describing shapes such as a rectangular shape or a cylindrical shape do not only refer to shapes such as a rectangular shape or a cylindrical shape in the strict geometric sense, but also refer to shapes that include uneven portions, chamfered portions, etc., to the extent that the same effect is obtained.
In addition, in this specification, the expressions "comprise,""include," or "have" a certain element are not exclusive expressions that exclude the presence of other elements.

1 (1A to 1C): Vacuum pump 2 (2A, 2B): Casing 3: Casing body 4: Pump cover 5: Top cover 10: Pump chamber 20: Intake passage 30: Exhaust passage 32: First exhaust passage 34: Second exhaust passage 50: First muffling chamber 60: Second muffling chamber (muffling chamber)
70: Extension pipe 72: Upstream portion 73: Nipple 74: Downstream portion 75: Hose 100: First part 102: Convex portion 106: Outer circumferential surface 108: Flat surface 113: Outer rim 200: Second part 202: Fitting hole 210: Outer rim portion 220: Concave portion 222: Bottom surface 300 (300A, 300B): Sealing member

Claims (9)

The pump includes a casing including a pump chamber and an intake passage and an exhaust passage communicating with the pump chamber,
The casing comprises:
a first part having a protrusion in which a first exhaust passage is formed;
a second component that defines a second exhaust passage that is in communication with the first exhaust passage among the exhaust passages, the second component having a fitting hole into which the protrusion can be fitted, and an outer circumferential edge portion that is provided on an outer circumferential side of the fitting hole and protrudes toward the first component;
Including,
The vacuum pump further includes a sealing member held between the first part and the second part so as to be positioned radially between the convex portion of the first part and the outer circumferential edge portion of the second part, for sealing the exhaust passage including the first exhaust passage and the second exhaust passage. the first part is located above the second part,
2. The vacuum pump according to claim 1, wherein the protrusion of the first component is provided so as to protrude downward toward the second component and is fitted into the fitting hole of the second component. an extension tube attached to the second component so as to communicate with the exhaust passage, the extension tube being connected to an end of the fitting hole on an opposite side to an end of the fitting portion with the protruding portion;
The extension tube is
an upstream portion extending downward from the second component;
a downstream portion located downstream of the upstream portion and extending upward to a position higher than the second component;
Including,
3. The vacuum pump according to claim 2, wherein the extension pipe is configured to guide the exhaust flow that has passed through the first exhaust passage and the second exhaust passage to an outlet of the extension pipe that is located higher than the second component. The extension tube is
a nipple as the upstream portion press-fitted into the fitting hole of the second component so as to extend downward from the second component;
a U-shaped hose as the downstream portion attached to a portion of the nipple protruding from the second part;
4. The vacuum pump of claim 3, comprising: The casing comprises:
A pump cover as the first part;
A casing body as the second part;
a top cover that is attached to the pump cover and is located on the opposite side of the casing body with the pump cover in between;
Including,
The pump chamber is formed by the pump cover and the casing body by closing an opening of a recess provided in the casing body with the pump cover,
3. The vacuum pump according to claim 1, wherein a sound-absorbing chamber that guides the gas discharged from the pump chamber to the first exhaust passage is formed by the pump cover and the top cover above the pump chamber on the opposite side of the pump cover from the pump chamber. the first component has a flat surface facing the second component on an outer circumferential side of the protruding portion,
the second component has a recess that is recessed with respect to the outer circumferential edge portion on a radially inner side of the outer circumferential edge portion,
the fitting hole opens to a bottom surface of the recess facing the flat surface of the first component,
3. The vacuum pump according to claim 1, wherein the seal member is held in a sandwiched state between the flat surface of the first component and the bottom surface of the second component in the axial direction. 7. The vacuum pump according to claim 6, wherein the sealing member is sandwiched between the flat surface of the first component and the bottom surface of the second component in the axial direction, with a radial gap between the sealing member and an outer peripheral surface of the convex portion. 8. The vacuum pump according to claim 7, wherein the seal member is configured to be in close contact with the outer peripheral edge portion of the second component while being sandwiched between the flat surface of the first component and the bottom surface of the second component in the axial direction. 3. The vacuum pump according to claim 1, wherein the sealing member is held in a radially sandwiched state between an outer peripheral surface of the convex portion of the first component and an inner wall surface of the fitting hole that is continuous with an inner peripheral surface of the outer peripheral edge portion of the second component.

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