CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and benefit of Chinese Patent Application Serial No. 200810216288.0, filed in the State Intellectual Property Office of the P. R. China on September 20, 2008, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

FIELD OF THE INVENTION The present invention relates to a vacuum pump.

BACKGROUND OF THE RELATED ART

The vacuum pump is a device to create and maintain a vacuum in an enclosed space. Presently, a vacuum system comprising a vacuum pump, a vacuum valve, a meter and pipes etc. are widely used many industries.

The vacuum pumps can be sorted into gas transportation pumps and gas collection pumps. The gas transportation pumps, generally, include liquid ring vacuum pumps, reciprocating vacuum pumps and rotary vane vacuum pumps. The gas collection pumps include sorption pumps and cryopumps. The rotary vane vacuum pumps are used most widely due to a higher degree of vacuum and a compact structure thereof.

US patent No. 6491505Bl discloses a vacuum pump. As shown in FIG.l, the vacuum pump comprises a motor 1, a mounting base 2, a first base plate 3, a pumping rotor 4, a pumping ring 5, a second base plate 6 and a cap 7. The shaft of the motor 1 penetrates through the mounting base 2, the first base plate 3 and the pumping rotor 4. The pumping rotor 4 is rotated by the motor 1. The second base plate 6, the pumping ring 5 and the first base plate 3 are attached to the mounting base 2 by fastening screws. When the motor 1 is turned on, the pumping rotor 4 is actuated to rotate in a chamber of the pumping ring 5. Meanwhile, air flows into the chamber of the pumping rotor 4 through an intake port 8 and a first inlet passage 9 of the mounting base 2, a second inlet passage 10 of the first base plate 3. Then, the air flows into a chamber of the cap 7 and is discharged through the outlet passage 11 of the mounting base 2.

When the vacuum pump is operated, the air flows out of the vacuum pump with high speed. The vacuum pump does not have a structure to lower down the flowing speed of the air to reduce the noise from the vacuum pump. Thus, large noise occurs when the vacuum pump is operated. At the same time, a cap is positioned out of the pumping ring which may prevent heat from the compressed air from dissipating. Thus, the vacuum pump does not dissipate the heat effectively.

SUMMARY OF THE INVENTION

In viewing thereof, the present invention needs to provide an improved vacuum pump with reduced noise level and higher thermal dissipation efficiency.

According to an embodiment of the invention, a vacuum pump is provided to achieve at least one of the technical problems mentioned above, the vacuum pump may comprise an actuator with an actuating shaft; a mounting base with a first side being attached to the actuator; a pumping device having a pumping ring being attached to a second side of the mounting base opposite to the first side; and a sound-proof cap being attached to an end face of the pumping ring and the pumping device being driven by the actuating shaft penetrating through the mounting base. The end face of the pumping ring in the pumping device may be covered by a first base plate with a hollow dampening member interposed between an inner surface of the sound-proof cap and a side of the first base plate facing thereto, dividing a space encircled therein into an inner dampening chamber and an outer dampening chamber communicating with each other. The mounting base may be formed with an air-intake column for drawing in air into the pumping device. The pumping ring may be formed with an air discharge port. The inner dampening chamber may be communicated with the pumping device whereas the outer dampening chamber may be communicated with the air discharge port.

In the vacuum pump according to an embodiment of the present invention, the air flows from the pumping device into the inner dampening chamber, then the air runs into the outer dampening chamber. Because the inner dampening chamber has a volume smaller than that of the outer dampening chamber, the air flows is slowed down effectively by the presence of the hollow dampening member. Accordingly, the noise is reduced effectively. Further, the sound-proof cap is attached to the pumping ring, thus the first base plate and the pumping ring are directly exposed in the air. Accordingly, the heat from the air can be dissipated efficiently by being directly discharged into the air from the pumping ring.

Additional aspects and advantages of the embodiments of present invention will be given in part in the following descriptions, become apparent in part from the following descriptions, or be learned from the practice of the embodiments present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The aforementioned features and advantages of the invention as well as additional features and advantages thereof will be more clearly understood hereinafter as a result of a detailed description of embodiments when taken in conjunction with the drawings, in which:

FIG.l is an exploded perspective view illustrating a prior vacuum pump. FIG.2 is an exploded perspective view of a vacuum pump according to an embodiment of the invention; and FIG.3 is a perspective view of a sound-proof cap in the vacuum pump according to an embodiment of the invention.

DESCRIPTION OF THE EMBODIMENTS

Reference will be made in detail to embodiments of the present invention. The embodiments described herein with reference to drawings are explanatory, illustrative, and used to generally understand the present invention. The embodiments shall not be construed to limit the present invention. The same or similar elements and the elements having same or similar functions are denoted by like reference numerals throughout the descriptions.

According to an embodiment of the invention, as shown in FIG. 2, a vacuum pump is provided. The vacuum pump may comprise an actuator 20 with an actuating shaft 201; a mounting base 21 with a first side being attached to the actuator 20; a pumping device 10 having a pumping ring 28 being attached to a second side of the mounting base 21 opposite to the first side; and a sound-proof cap 34 being attached to an end face of the pumping ring 28 and the pumping device 10 being driven by the actuating shaft 201 penetrating through the mounting base 21. The end face of the pumping ring 28 in the pumping device 10 may be covered by a base plate 31 with a hollow dampening member 33 interposed between an inner surface of the sound-proof cap 34 and a side of the base plate 31 facing thereto, dividing a space encircled therein into an inner dampening chamber 36 and an outer dampening chamber 37 communicating with each other. The mounting base 21 may be formed with an air-intake column 211 for drawing in air into the pumping device 10. The pumping ring 28 may be formed with an air discharge port 282. The inner dampening chamber 36 may be communicated with the pumping device 10 whereas the outer dampening chamber 37 may be communicated with the air discharge port 282.

The following will describe an embodiment of the invention in detail with reference to accompanying figures. It should be noted that members, components and/or modules described hereunder are only for illustration purpose rather than limitation. For example, the mounting base may be implemented as a mounting plate which will be described hereinafter which is only for illustration purpose. Those skilled in the art can obviously use other means for positioning the vacuum pump. According to an embodiment of the invention, as shown in FIG.2, the vacuum pump comprises an actuator 20 with an actuating shaft 201, a mounting base 21, pumping device 10, a base plate 31 and a sound-proof cap 34. The pumping device 10 comprises a base plate 24, a pump rotor 26 and a pump ring 28. The first side of the mounting base 21 is attached to the actuator 20, and is penetrated by the actuating shaft 201. In addition, the mounting base 21 may be formed with an air-intake column 211 for drawing in air into the pumping device 10.

The pumping ring is attached to a second side of the mounting base opposite to the first side. In particular, the pumping ring 28 is positioned between the base plate 24 and the base plate 31. The base plate 24 has an opening 241. And, the base plate 31 has an opening 311.

The actuating shaft 201 of the actuator 20 is connected to the pumping rotor 26 after penetrating the base plate 24. The pumping rotor 26 is positioned in the chamber 29 which is enclosed by the base plate 24, the pumping ring 28 and the base plate 31.

The opening 212, the opening 241, the chamber 29 and the opening 311 are all communicated with each other.

The sound-proof cap 34 is attached to an end face of the pumping ring 28. And, the sound-proof cap 34, the base plate 31, the pumping ring 28 and the base plate 24 are attached to the second side of the mounting base 21 by fastening screws 35 in sequence.

The vacuum pump further includes a hollow dampening member 33. The hollow dampening member 33 is interposed in a space between an inner surface of the sound-proof cap 34 and a side of the base plate 31 facing thereto. Then, the space may be divided into the inner dampening chamber 36 and the outer dampening chamber 37 communicating with each other.

The inner dampening chamber 36 is enclosed by the inner surface of the hollow dampening member 33, the base plate 31 and the sound-proof cap 34; While the outer dampening chamber 37 is enclosed by the outer surface of the hollow dampening member 33, the base plate 3 land the sound-proof cap 34 or enclosed by the outer surface of the hollow dampening member 33, the base plate 31, the sound-proof cap 34 and the pumping ring 28. The opening 311 of the base plate 31 is communicated with the inner dampening chamber 36.

An opening is formed on one of the sound-proof cap 34 and the hollow dampening member 33 or the both can be communicated with inner dampening chamber 36 and the outer dampening chamber 37. The pumping ring 28 may be formed with an air discharge port 282 and an outlet opening 281 respectively. The outlet opening 281 is communicated with the air discharge port 282 and the outer dampening chamber 37.

The actuator 20 can be an electromotor or an engine of many types.

Particularly, the actuator 20 is attached to the first side of the mounting base 21. The actuating shaft 201 of the actuator penetrates the mounting plate 21 and is connected to the pumping rotor 26. The mounting plate 21 has an air-intake column

211 which is communicated with the opening 212 of the mounting plate 21.

Namely, the mounting plate 21 has an inlet channel. One end of the inlet channel is the air-intake column 211, while the other end is the opening 212 of the mounting plate 21. The air-intake column 211 may be positioned on the up end surface of the mounting plate 21, on the down end surface of the mounting plate 21, or on the profile of the mounting plate 21. Alternatively, the air-intake column 211 is positioned on the profile of the mounting plate 21.

The mounting plate 21 may also include mounting parts (not shown) , so that the mounting plate 21 can be fixed in site. For example, the mounting parts may be formed as a plurality of screw holes, in order to fix the mounting plate 21 by screws.

The base plate 24 with an opening 241, the pumping rotor 26 with a plurality of vanes 27, the pumping ring 28 and the base plate 31 with anopening 311 are attached to the second side of the mounting plate 21. The pumping ring 28 is positioned between the base plate 24 and the base plate 31. The actuating shaft 201 of the actuator 20 penetrating the base plate 24 is connected to the pumping rotor 26 positioned in the chamber 29. The chamber 29 is enclosed by the base plate 24, pumping ring 28 and base plate 31. The opening 212, the opening 241, the chamber 29 and the opening 311 are communicatedwith each other.

According to an embodiment of the invention, the actuating shaft 201 is connected to the pumping rotor 26 via a connecting member 25, as shown in FIG.2. The connecting member 25 may be a hollow component with irregular shape. Alternatively, the connecting member 25 may be formed into a spindle sleeve with a column. It is clear in FIG.2 that the column is longer than the spindle sleeve. The pumping rotor 26 may be formed with an opening, such as a keyway, by which the connecting member 25 is connected to the pumping rotor 26. And, both the position and the shape of the opening are adapted to those of the connecting member 25. The actuating force of the actuating shaft 201 is transferred to the pumping rotor 26 due to the column which offsets to the center of the pumping rotor 26.

The air-intake column 211, the opening 212 and the opening 241 form an inlet channel in the chamber 29. When the pumping rotor 26 with a plurality of vanes 27 rotates at a high speed, air passes through the inlet channel into the chamber 29. According to an embodiment of the invention, as shown in FIG.2, a sealing ring 22 is positioned between the opening 212 and the opening 241 in order to satisfy the sealing requirement. It can be avoided that air leaks through the gap between the mounting plate 21 and the base plate 24. The sealing ring 22 can be made of metal, elastic material or plastic. Alternatively, the sealing ring 22 is made of elastic material, such as rubber.

To satisfy the sealing requirement between the mounting plate 21 and the base plate 24 or between the mounting plate 21 and the pumping ring 28, a sealing groove, such as an annular groove, may be configured on the upper surface of the mounting plate 21 and a sealing ring 23 is positioned in the sealing groove. To satisfy the sealing requirement between the pumping ring 28 and the sound-proof cap 34 or between the pumping ring 28 and the base plate 31, a sealing groove, such as an annular groove, may be configured on the upper surface of the pumping ring 28 and a sealing ring 30 is positioned in the sealing groove. As shown in FIG.2, the sound-proof cap 34, the base plate 31, the pumping ring 28 and the base plate 24 are attached to the second side of the mounting plate 21 in sequence via fastening screws.

Furthermore, the vacuum pump also comprises first fastening screws 32 and second fastening screws 35. The first fastening screws 32 penetrate the base plate 31, the pumping ring 28, and the base plate 24, and fix these components to the mounting base 21. Additionally, the second fastening screws 35 may be fixed as follows. The second fastening screws 35 may be fixed to the pump ring 28 while penetrating through the sound-proof cap 34, or the second fastening screws 35 may be fixed to the pump ring 28 while penetrating through the sound-proof cap 34 and the base plate 31; or the second fastening screws 35 may be fixed to the base plate 31 while penetrating through and fastening the sound-proof cap 34 and pump ring 28.

According to another aspect of the invention, the outer surface of the pumping ring 28 and the base plate 24 may be exposed in the air and so it is much easier to dissipate heat accordingly.

According to an embodiment of the invention, in order to reduce noise during operation, the vacuum pump may also comprise the hollow dampening member 33. As shown in FIG.2 and FIG.3, the hollow dampening member 33 is interposed in a space between the inner surface of the sound-proof cap 34 and the side of the base plate 31 facing the inner surface. Thus, the space can be divided into the inner dampening chamber 36 and the outer dampening chamber 37 communicating with each other. The inner dampening chamber 36 is enclosed by the inner surface of the hollow dampening member 33, the base plate 31 and the sound-proof cap 34 while the outer dampening chamber 37 is enclosed by the outer surface of the hollow dampening member 33, the base plate 31 and the sound-proof cap 34, or enclosed by the outer surface of the hollow dampening member 33, the base plate 31, the sound-proof cap 34 and the pumping ring 28.

The opening 311 of the base plate 31 is communicated with the inner dampening chamber 36. Moreover, the opening 38 may be formed on the sound-proof cap 34, on the hollow dampening member 33 ,or on the corresponding position of the both respectively to communicate the inner dampening chamber 36 with the outer dampening chamber 37.

Further, the air discharge port 282 may be configured on a circumferential surface of the pumping ring 28. And the air discharge port 282 is communicated with the outer dampening chamber 37 via the outlet opening 281.

In the sound-proof cap 34, the opening 311 of the base plate31 is communicated with the inner dampening chamber 36. And the inner dampening chamber 36 is communicated with the outer dampening chamber 37 via the opening 38. Furthermore, the outer dampening chamber 37 is communicated with the outside of the vacuum pump via the outlet opening 281 and the air discharge port 282. Thus, the outlet channel forms via the opening 311, the inner dampening chamber 36, the opening 38, the outer dampening chamber 37, the outlet opening 281 and the air discharge port 282. Additionally, the opening 38 may be positioned in the sound-proof cap 34 or in the hollow dampening member 33 to ensure the comm of the inner dampening chamber 36 and the outer dampening chamber 37.

According to an embodiment of the invention, the inner dampening chamber 36 has a volume smaller than that of the outer dampening chamber 37, and larger than that of chamber 29. In that manner, the buffering of the outer dampening chamber 37 is stronger than that of the inner dampening chamber 36. When the vacuum pump is operated and the compressed air in the chamber 29 flows into the inner dampening chamber 36 via the opening 311 at a high speed, the air will slow down because of the buffering or dampening of the inner dampening chamber 36. Then, when the air flows from the inner dampening chamber 36 into the outer dampening chamber 37 through the opening 38, the air will slows down further due to the buffering or dampening of the outer dampening chamber 37. Finally, the air is expelled out of the vacuum pump after passing through the air discharge port 282. In addition, when the air passes through the inner dampening chamber 36 and the outer dampening chamber 37, the noise can be reduced at the same time due to the buffering or dampening.

It is clearly in FIG.2 that the air discharge port 282 of the vacuum pump is positioned in the pumping ring 28 rather than in the mounting plate 21. The result is that it is easier to manufacture the mounting plate 21. And the vacuum pump operates more effectively as the flowing distance of the air is shortened.

Moreover, when the vacuum pump is operated, the temperature of the compressed air will be high. If the compressed air with high temperature can not be expelled rapidly, the life of the vacuum pump will be shortened. In the vacuum pump shown in FIG.1 , because the outlet channel is long, the compressed air with high temperature stays in the vacuum pump for a long time. It is disadvantageous to the life of the vacuum pump. By contrast, the outlet channel of the vacuum pump shown in FIG.2 is shortened. The compressed air with high temperature could stay in the vacuum pump for a shorter time. Thus, the vacuum pump of the present invention may dissipate heat faster, and prolong the life of the vacuum pump correspondingly.

According to an embodiment of the invention, the hollow dampening member 33 is clamped between the inner surface of the sound-proof cap 34 and the base plate 31. As result, the hollow dampening member 33 can not only adequately reducing noise, but also efficiently dissipate heat of the components between the base plate 31 and the base plate 24.

The hollow dampening member 33 may be formed as circumstances may require, as long as the interior chamber of the sound-proof cap 34 may be divided into the inner dampening chamber 36 and the outer dampening chamber 37. For example, the hollow dampening member 33 is circular ring. Thus, the inner dampening chamber 36 is enclosed by the inner surface of the hollow dampening member 33, the base plate 31, and the sound-proof cap 34. Furthermore, the outer dampening chamber 37 is enclosed by the outer surface of the hollow dampening member 33, the base plate 31, and the sound-proof cap 34 , or enclosed by the outer surface of the hollow dampening member 33, the base plate 31, the sound-proof cap 34, and the pumping ring 28.

The sealing ring 22 may be made of metal, elastic material or plastic. Alternatively,, the hollow dampening member 33 is made of elastic material such as rubber and elastic polyurethane. Additionally, it is tightly pressed by the sound-proof cap 34 and the base plate 31 , in order to satisfy the sealing requirement between the hollow dampening member 33 and the sound-proof cap, and between the hollow dampening member 33 and the base plate 31.

The sound-proof cap 34 can be attached to the hollow dampening member 33 in many ways to ensure that the interior chamber of the sound-proof cap 34 may be divided into an inner dampening chamber 36 and an outer dampening chamber 37.

As shown in FIG.3, according to one embodiment of the invention, the sound-proof cap 34 further comprises a circular flange 342 which is axially extended from the inner surface of the sound-proof cap 34. The hollow dampening member 33 may be set on the circular flange 342, in order to mount in site conveniently. In addition, the hollow dampening member 33 is longer than the circular flange 342, so that it is avoided that the base plate 31 touches with the circular flange 342 directly. Additionally, the sealing requirement of the vacuum pump is satisfied.

According to another embodiment of the invention, as shown in FIG.3, a stage 341 is configured on the bottom of the circular flange 342 in order to position the hollow dampening member 33 more conveniently. The opening 38 is configured as a groove formed in the stage for the sake of communication between the inner dampening chamber 36 and the outer dampening chamber 37. According to other embodiment of the invention, the opening 38 may be configured in the hollow dampening member 33 or configured in the corresponding positions of the flange 342 and the hollow dampening member 33, as long as the inner dampening chamber 36 is communicated with the outer dampening chamber 37.

The pumping ring 28 has an air discharge port 282 and an outlet opening 281 communicated with the air discharge port 282. The outlet opening 281 is positioned on the upside surface of the pumping ring 28 while the air discharge port 282 can be appropriately positioned in any place of the pumping ring 28, such as, on the outer circumferential surface of the pumping ring 28, on the upper portion of the pumping ring 28, or on the lower surface of the pumping ring 28. Alternatively, the air discharge port 282 is positioned on the outer circumferential surface of the pumping ring 28. An outlet channel is formed via the air discharge port 282 and an outlet opening 281. One end of the outlet channel is the outlet opening 281, while the other end is the air discharge port 282. The outlet opening 281 is communicated with the outer dampening chamber 37. For this purpose, several ways as follows can be available: firstly, an opening or a recess is positioned in the base plate 31 ; Secondly, the radius of the base plate 31 is small enough to ensure the communication without any opening.

The principles of the preferred embodiments described herein are therefore illustrative and not restrictive, the scope of the invention being indicated in the appended claims and all variations which come within the spirit and meaning of the claims are intended be embraced therein.