JP2013528741A - Gas pump with reduced noise - Google Patents

Abstract

  A gas pump closes the pump casing (105) in the axial direction, a pump rotor (115) for pumping a gaseous medium, a pump casing (105) rotatably accommodating the pump rotor (115) It has a restricting member (125) and a closing member (130) that forms a silencer with the restricting member (125). The restricting member includes an opening (230) for allowing a medium to flow between the pump casing (105) and the silencer, and a web (220) extending in the axial direction. Surrounding (230) in the radial direction, the closure member (130) abuts against the web (220) in the axial direction.

Description

BACKGROUND ART Various pumps are used for pumping gaseous media, for example in the automotive field. A vane pump is usually used to generate a vacuum pressure that is necessary for a negative pressure controlled brake booster. As with many pumps, the medium exiting the vane pump is pulsating, which can cause unpleasant noise for people in the vehicle range.

  German Offenlegungsschrift 19933664 proposes to form an air pump with a built-in silencer, which is a cylindrical hollow chamber, in the hollow chamber. The medium exiting from the pump chamber flows in. A cap-shaped component houses the pump chamber, and a hollow chamber is formed between the pump chamber and the inner restricting portion of the cap.

  The object of the present invention is to provide a pump with a built-in silencer that can be easily manufactured.

DISCLOSURE OF THE INVENTION The object of the present invention is solved by a pump having the features of claim 1. More preferred configurations are described in the dependent claims.

  A gas pump according to the present invention includes a pump rotor that pumps a gaseous medium, a pump casing that rotatably accommodates the pump rotor, a limiting member that axially closes the pump casing, and a hollow that is hollow together with the limiting member. And a closure member forming a chamber. The restricting member has an opening through which a medium flows between the pump casing and the hollow chamber, and a web extending in an axial direction, and the web surrounds the opening in a radial direction, The closure member abuts against the web in the axial direction.

  With such a configuration, the closure member can have a very simple shape, which provides a cost advantage. The remaining part of the hollow chamber is defined by a restricting member, which can be manufactured in one process, which requires little additional effort to produce the web. In a preferred configuration, the contact surface between the web and the closure member is flat. Thus, the simplest closure member may be a flat component of uniform thickness, for example a thin cover.

  The restricting member may have another web, which separates the hollow chamber into a plurality of partial hollow chambers connected to each other. Thereby, since the pulsation of the flow of the medium flowing out from the pump casing can be effectively attenuated, an improved noise reduction can be obtained. In one configuration, the two hollow chambers may be of different sizes. This can further mute the sound. It is also possible to define two or more partial hollow chambers by means of a web inside the silencer, which can further improve the silence. Since all the webs extend in the axial direction, the manufacturing cost of the limiting member is substantially the same even when the web structure is complex.

  The partial hollow chambers can define selective multiple paths of different lengths for the media through the silencer. By superimposing pulsating medium flows that have passed through different selective paths, the pulsation can be eliminated, thereby further attenuating noise. Ideally, the length of each path differs by an amount corresponding to half the wavelength of the pulsating media stream.

  One of the partial hollow chambers may have only one penetration that allows the medium to pass into or out of the partial hollow chamber. This partial hollow chamber can act as a Helmholtz resonator with respect to the frequency at which the media flow pulsates. Inside this partial hollow chamber, another measure can be taken to convert the energy of the pulsating medium into another form of energy, for example heat.

  One of the partial hollow chambers is a passage, and the length of the passage is larger than the width and height of the passage, and the passage is a projecting portion in cross section and opens to an adjacent partial hollow chamber. ing. The cross section may decrease or increase with respect to the direction of media flow. In this case, the channel preferably has a rectangular cross section, so that the best possible reflection is obtained in the cross-sectional flow.

  The hollow chamber has an inner contour section with different curvatures. This inner contour is preferably formed by a section of one web. Straight sections are more suitable as reflective surfaces than curved sections. As a result, the medium that spreads intermittently is changed so that the overall silencing rate is increased.

  A porous element can be arranged in the hollow chamber. The porous element may be, for example, a foam rubber having a large surface area. The kinetic energy of the pulsating medium can be converted into heat by the porous element. In one configuration, the Helmholtz resonator is partially or fully filled with a porous element.

  Preferably, the limiting member is a sintered member. The sintered member is particularly suitable as a friction partner for the pump rotor due to the open cell surface. This is because a transfer film made of wear material is formed between the friction partners, thereby further minimizing wear. Further, the restricting member can be formed in an almost arbitrary shape with a little effort by the manufacturing process of the sintered member. By providing the limiting member formed according to the invention and the corresponding closing member, the gas pump formed is space-saving and a hollow chamber acting as a silencer can be provided at a slight additional cost.

  The invention will now be described in detail with reference to the drawings.

It is the figure which showed the gas pump. It is the figure which showed the structure of the silencer for the gas pump of FIG. It is the figure which showed another structure of the silencer for the gas pump of FIG. It is the figure which showed another structure of the silencer for the gas pump of FIG. It is the figure which showed another structure of the silencer for the gas pump of FIG. It is the figure which showed another structure of the silencer for the gas pump of FIG.

Detailed Description of Embodiments FIG. 1 is a perspective view of a gas pump 100. The gas pump 100 has a pump casing 105, which is closed by a pump bottom plate 110 with respect to the lower side. A pump rotor 115 that is rotatable about a vertical axis is disposed in the pump casing 105. For this purpose, the pump rotor 115 can be driven by an electric motor arranged below the pump bottom plate 110 via a shaft not shown.

  The pump rotor 115 has three slits extending at a predetermined angle from a predetermined circumference around the rotation axis of the pump rotor to an outer edge of the pump rotor 115. Each slit accommodates one vane 120, and this vane 120 is held on the inner peripheral surface of the pump casing 105 by centrifugal force and / or a spring element. The inner surface of the pump casing 105 is a cylindrical surface centered on a central axis that is shifted parallel to the rotational axis of the pump rotor 115. Accordingly, the silencer 125, the pump bottom plate 110, the inner wall of the pump casing 105, the outer wall of the pump rotor 115, and the pump chambers A, B, and C respectively formed between the two adjacent vanes 120 are pumps. The rotors 115 have different volumes depending on the rotational position of the rotor 115.

  The pump casing 105 is adjacent to the pump bottom plate 110 in the downward direction in the axial direction, and is adjacent to the silencer 125 in the upward direction in the axial direction. The silencer 125 is shown here transparently, but is shown in more detail in FIGS. The silencer 125 is in contact with the pump cover 130 in the upper axial direction. In the pump cover 130, a suction pipe piece 135 extends upward in the axial direction, and this suction pipe piece 135 opens to a vertical through opening 140 provided in the silencer 125. The through-opening 140 ends with a suction opening 160 arranged in a region between the outer peripheral surface of the pump rotor 115 and the inner peripheral surface of the pump casing 105. Similar to the suction opening 160, the silencer 125 is removed from the inner chamber of the pump casing 105 by an outflow opening 145 disposed at another location in the region between the outer peripheral surface of the pump rotor 115 and the inner peripheral surface of the pump casing 105. Gas can flow to Thus, the gas that has entered the silencer 125 flows through the silencer 125 and flows out from the exhaust opening 150 into the surrounding atmosphere.

  The gas pump 100 is preferably used as a vacuum pump for the air medium. The gas pump 100 can be used for exhaust of an automobile brake booster. For this purpose, the brake booster is connected to the suction pipe piece 135. The pump rotor 115 rotates clockwise about its vertical rotation axis. 1, when the pump chamber A connected to the suction pipe piece 135 is further rotated in the clockwise direction, the lower vane 120 is connected between the pump chamber A and the suction pipe piece 135 after a predetermined rotation. Shut off. The pump rotor 115 is further moved clockwise, and at this time, the volume of the pump chamber A continuously decreases. Eventually, the pump chamber A is moved along the inner surface of the pump casing 105 until the forward vane 120 that restricts the pump chamber A passes through the outflow opening 145. In FIG. 1, this position corresponds to the pump chamber B. Next, the pressurized gas flows from the pump chamber B to the silencer 125.

  The pump rotor 115 is further rotated until one of the vanes 120 breaks the connection between the pump chamber B and the outflow opening 145. This position corresponds to the pump chamber C in FIG.

  When the pump rotor 115 further rotates, immediately after that, the connection to the suction opening 160 is opened by another vane 120, and the pump chamber again corresponds to the pump chamber A of FIG. The pump rotor 115 rotates further and the volume of the pump chamber A increases continuously until the rear vane 120 blocks the connection of the pump chamber to the suction opening 160. The above process can then be performed again. Since three vanes define three pump chambers A, B, and C along the peripheral surface of the pump rotor 115, the above process is performed three times out of phase with each rotation of the pump rotor 115. Is called.

  2 to 6 show different configurations of the silencer 125 of FIG. In all configurations, the silencer 125 has a base plate 210, and the web 220 extends upward in the vertical direction from the base plate 210. The upper end of the web 220 is flat. The web 220 surrounds the inlet 230 corresponding to the outflow opening 145 of FIG. An exhaust opening 150 is provided at one location of the web 220. The web 220 surrounds the inlet 230 in the radial direction, that is, the volume of the silencer 125 is limited by the web 220 in the radial direction. The volume of the silencer 125 is limited by the base plate 210 in the lower part in the vertical direction and by the pump cover 130 (see FIG. 1) in the upper part.

  Furthermore, the silencer 125 has a through-opening 160, and the through-opening 160 opens into the circular suction pipe piece 135 at the upper side and the suction opening 140 at the lower side (see FIG. 1). In another configuration of the gas pump 100, the suction pipe piece 135 may communicate with the pump casing 105 at another location, for example, in a radial direction. As a result, a free space can be additionally used by the silencer 125.

  The silencer 125 shown in FIG. 2 has the largest volume with respect to spatial conditions. There is no reflective or guide element for gas flowing into the volume from the inlet 230 and exiting the silencer 125 from the exhaust opening 150. The inner radial contour of the silencer 125 is generally circular, but straight sections may be provided that can act as a reflective surface for gas or sound waves.

  In the configuration of the silencer 125 shown in FIG. 3, two other webs 250 are provided, which extend, for example, vertically from the web 220 and extend towards each other in a radial plane. A through-hole 260 is formed between each other. The silencer 125 is divided into partial hollow chambers of different sizes by another web 250, and these partial hollow chambers are connected to each other by a through portion 260. The gas flow path from the inlet 230 to the exhaust opening 150 extends through both the hollow chambers and the through portion 260. In another configuration not shown, one of the partial hollow chambers is connected only to the other partial hollow chamber by the through-hole 260, and the inlet 230 and the exhaust opening 150 are located in the region of the other partial hollow chamber. ing. Gas does not flow through the former partial hollow chamber, but this partial hollow chamber acts as a resonance volume, in particular as a Helmholtz resonator.

  In the configuration of the silencer 125 shown in FIG. 4, a plurality of other webs 250 form one passage 270. Along the gas path, the passage 270 has a substantially constant cross-section. Preferably, this cross section is rectangular. The passage 270 has a length adapted to the wavelength of the gas flowing out from the inlet 230 or the wavelength of the sound wave. In another configuration not shown, a further web is located in the silencer 125, thereby providing at least two alternative paths for gas from the inlet 230 to the exhaust opening 150; Since these paths have different lengths, sound waves or gas waves cancel out where they meet each other. Paths of different lengths can be formed by a corresponding plurality of passages 270. In this case, the passage 270 may open into a partial volume of the silencer 125 or may exit from this partial volume or be directly connected to the inlet 230 or the exhaust opening 150.

  In the silencer configuration of FIG. 5, a passage 270 is formed by another web 250 in a manner similar to FIG. 4. In addition, a very short passage or penetration 260 is formed between the other two webs 250. Along the gas flow path from the inlet 230 to the exhaust opening 150, cross-sectional protrusions are formed on the end of the passage 270 and on both side surfaces of the through-hole 260. Such a cross-sectional protrusion can be used for partial reflection of sound waves or gas waves, and is suitable for further enhancing the effect of the silencer 125.

  In the configuration shown in FIG. 6, a porous element such as foam rubber or foam rubber is present in the volume of the silencer 125. In the illustrated configuration, the porous element 280 is provided with a wedge-shaped notch 240 that directly connects the inlet 230 and the exhaust opening 150. In another configuration, any portion or partial hollow chamber or passage 270 can be covered or filled with a porous element 280. Furthermore, the foam rubber may have a coating, for example a film, on at least one side.

  It is added that the means shown in FIGS. 2 to 6 for constituting the silencer 125 can be combined with each other in an arbitrary form. For example, the differently sized partial hollow chambers shown in FIG. 3 can be successfully combined with one of the passages 270 configured as shown in FIG. In another configuration, the passage of FIG. 4 can be combined with the circular limiting contour of FIG.

Claims (10)

A pump rotor (115) for pumping a gaseous medium;
A pump casing (105) rotatably housing the pump rotor (115);
A limiting member (125) for axially closing the pump casing (105);
A closing member (130) that forms a hollow chamber for accommodating the pumping medium together with the restricting member (125);
The restriction member (125) is a gas pump (100) having an opening (230) through which a medium flows between the pump casing (105) and the hollow chamber,
The restricting member (125) includes an axially extending web (220) that radially surrounds the opening (230), and the closing member (130) is axially extending from the web. A gas pump being in contact with (220).   The gas pump of claim 1, wherein a contact surface between the web (220) and the closure member (130) is flat.   The restriction member (125) has another web (250), which further divides the hollow chamber into a plurality of partial hollow chambers connected to each other. The gas pump according to 1 or 2.   The gas pump according to claim 3, wherein the two partial hollow chambers have different sizes.   The gas pump according to claim 3 or 4, wherein the partial volume forms a plurality of selective paths having different lengths for the medium passing through the hollow chamber.   One of the said partial hollow chambers has only one penetration part (260) which lets the said medium pass into this partial hollow chamber, or flows out of this partial hollow chamber, The any one of Claim 3-5 The gas pump according to claim 1.   One of the partial hollow chambers is one passage (270), and the length of the passage is larger than the width and height of the passage, and the passage (270) is an adjacent portion in the cross-sectional protrusion. The gas pump according to any one of claims 3 to 6, wherein the gas pump opens to the hollow chamber.   The gas pump according to any one of claims 1 to 7, wherein the hollow chamber has inner contour sections having different curvatures.   The gas pump according to any one of claims 1 to 8, wherein a porous element (280) is arranged in the hollow chamber.   The gas pump according to any one of claims 1 to 9, wherein the limiting member (125) is a sintered member.

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