Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
  • F04D29/00—Details, component parts, or accessories
  • F04D29/26—Rotors specially for elastic fluids
  • F04D29/28—Rotors specially for elastic fluids for centrifugal or helico-centrifugal pumps for radial-flow or helico-centrifugal pumps
  • F04D29/281—Rotors specially for elastic fluids for centrifugal or helico-centrifugal pumps for radial-flow or helico-centrifugal pumps for fans or blowers
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
  • F04D17/00—Radial-flow pumps, e.g. centrifugal pumps; Helico-centrifugal pumps
  • F04D17/06—Helico-centrifugal pumps
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
  • F04D25/00—Pumping installations or systems
  • F04D25/02—Units comprising pumps and their driving means
  • F04D25/06—Units comprising pumps and their driving means the pump being electrically driven
  • F04D25/0606—Units comprising pumps and their driving means the pump being electrically driven the electric motor being specially adapted for integration in the pump
  • F04D25/0613—Units comprising pumps and their driving means the pump being electrically driven the electric motor being specially adapted for integration in the pump the electric motor being of the inside-out type, i.e. the rotor is arranged radially outside a central stator
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
  • F04D29/00—Details, component parts, or accessories
  • F04D29/26—Rotors specially for elastic fluids
  • F04D29/28—Rotors specially for elastic fluids for centrifugal or helico-centrifugal pumps for radial-flow or helico-centrifugal pumps
  • F04D29/30—Vanes

Definitions

• the invention relates to a fan, in particular for ventilation or cooling of electronic devices such as personal computers.
• flat axial fans are usually used, which have a cylindrical annular space as a flow channel and inclined blades.
• the flow thus runs axially through the impeller.
• a high volume flow can thus be achieved at low pressure differences.
• radial fans are known, for example, for use in hair dryers, which can overcome a higher flow resistance by building up larger pressure differences.
• radial fans are rather unsuitable for installation in PC housings because of the radial or tangential air flow.
• Mixed forms are also known, in particular as so-called semi-axial fans, which have a diagonal flow component in the case of regionally overlapping, inclined blades. Such fans also have noise disadvantages in computer applications.
• the object of the invention is to provide a fan which avoids the disadvantages mentioned above and achieves a high degree of efficiency with regard to efficient ventilation and cooling with little noise.
• the design should be well suited for installation in computer housings and match the typical system characteristics.
• the invention is based on the idea of using a fan with a radial flow through the radial wheel in order to achieve a wide, favorable working range. Accordingly, a fan with the following features is proposed according to the invention:
• a fan housing delimiting a flow channel on the outside by a guide surface
• an impeller which is mounted in the fan housing so as to be rotatable about an axis of rotation and with its hub which is arranged concentrically with the guide surface and delimits the flow channel on the inside,
• the blades of the impeller which are preferably distributed unevenly over the circumference of the hub, lie in cylindrical surfaces which run parallel to the axis of rotation and are curved backwards counter to the direction of rotation, -
• the guide surface and the hub are designed to widen conically or slightly curved in the direction of flow between the blade inlet edge and the blade outlet edge , whereby the clear flow area of the flow channel remains constant or decreases.
• a radial working principle is thus achieved with a compact axial design.
• the blow-out direction is only slightly changed compared to axial fans, while a significant increase in pressure is achieved with a comparable volume flow.
• the special routing of the flow channel diagonally through the impeller leads to a constant throttle curve and thus enables the working point to be optimized over a wide range.
• the guide surface in the blade area should be axially steeper than the hub. It is further advantageous if the guide surface in the blade area has essentially the shape of a truncated cone with a cone angle between 20 ° and 60 °, preferably 40 °, and if the hub in the blade area essentially has the shape of a truncated cone with a cone angle between 80 ° and 110 °, preferably 95 °.
• the hub is parabolic, at least in its apex area. It is also expedient if the inlet area of the guide surface is rounded outwards via an inlet radius.
• the inlet and outlet openings of the flow channel advantageously have a mutual radial overlap.
• the blade exit edge toward the blade end is set at an acute angle of attack against the flow direction relative to the plane of the outlet opening of the flow channel. It should be ensured that the angle of attack is between 10 ° and 20 °, preferably 15 °. This ensures that turbulence on the downstream side and correspondingly also the noise development are minimized. A further improvement is achieved in that the free blade end edges run along the guide surface while maintaining a tolerance gap.
• the blade inlet edges extend axially beyond the hub towards the inlet opening.
• the blade leading edge has a radius of curvature of 1% to 4% and a profile thickness of 2% to 8% of the length of the free blade edge.
• An electric motor designed as an external rotor and arranged in a recess in the hub is advantageously used for rotating the impeller.
• Figure 1 shows a fan for PC devices in the upstream side view.
• Fig. 2 shows the fan of Fig. 1 with a simplified contoured blading shown in axial section.
• the fan shown in the drawing essentially consists of a housing 10, an impeller 18 rotatably mounted therein about an axis of rotation 12, having a hub 14 and blades 16 formed thereon, and a rotary drive 20 for the impeller 18.
• the housing 10 comprises an inner jacket as a guide surface 22, a flow channel 24 on the outside, while the concentric to the Guide surface 16 arranged hub 14 limits the flow channel 24 on the inside.
• the guide surface 22 has the shape of a truncated cone which widens in the direction of flow - downwards in FIG. 2, the cone angle being approximately 40 °.
• the inlet section 26 is rounded to the outside by delimiting the inlet opening 28 of the flow channel 24 over an inlet radius. This radius should be kept as large as possible to avoid the occurrence of turbulence on the inlet side. In principle, it is also possible for the guide surface to be slightly curved as a truncated paraboloid of revolution.
• the hub 14 is frustoconical in the base region 30 of the blades 16, the cone angle being 95 ° in the embodiment shown. In its apex region 32 facing the inlet opening 28, the hub 14 is parabolically shaped in order to avoid turbulence. It is also conceivable that the hub 14 has the overall shape of a paraboloid, possibly with a rounded trailing edge. In any case, it should be ensured that the guide surface 22 in the blade region, that is to say between the blade inlet edge 34 and the blade outlet edge 36, has a greater slope in the direction of the axis of rotation 12 than the hub 14, so that the mean diameter of the annular flow channel 24 there is constant or slightly decreasing clear flow area is constantly expanding. There is a radial overlap between the inlet opening 28 and outlet opening 38 of the flow channel 24, so that an annular region 40 is axially continuously open.
• the blades 16 are distributed asymmetrically over the circumference of the hub 14 and lie as pure radial blades in parallel to the axis of rotation 12, counter-clockwise (counterclockwise in Fig. 1) backward curved cylinder surfaces.
• the blade inlet edges 34 extend axially beyond the apex region 32 of the hub 14 to the inlet opening 28 and have a radius of curvature of 1% to 4% and a profile thickness of 2% to 8% of the length of the free blade end edges 42, which keep a tolerance gap free the guide surface 22 run.
• the blade exit edges 36 are set toward the blade end opposite the plane of the outlet opening 38 at an acute angle of attack against the flow direction, the angle of attack being approximately 15 ° in the embodiment shown.
• the entire fan wheel 18 is preferably produced as a one-piece injection-molded part made of plastic. It is favorable with regard to the demolding that the blades 16 do not overlap in the direction of rotation.
• the rotary drive 20 is formed by an electric motor designed as an external rotor, which is arranged in a cylindrical recess 44 in the hub 14.
• the rotor 46 is fixedly connected to the hub 14, while stator 52, which is seated on the rotor shaft 50 via roller bearings 48, is fixed on the outlet side on the outlet side by means of an annular flange 54 and frame webs 56 projecting radially therefrom.
• the invention relates to a fan, in particular for personal computers, in which the following combination of features is proposed in order to minimize noise: - An impeller (18) mounted in the fan housing (10) so as to be rotatable about an axis of rotation (12) and with its hub (14) which delimits the flow channel (24) on the inside,
• the blades (16) of the impeller (18) distributed asymmetrically over the circumference of the hub (14) are designed as radial blades
• the guide surface 22 and the hub 14 are designed to widen conically or slightly curved in the direction of flow in the blade area between blade inlet edge 34 and blade outlet edge 36, the clear flow surface of the flow channel 24 remaining constant or decreasing.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Structures Of Non-Positive Displacement Pumps (AREA)
• Cooling Or The Like Of Electrical Apparatus (AREA)

Applications Claiming Priority (3)

Publications (2)

Family

ID=7640230

Family Applications (1)

Country Status (7)

Families Citing this family (40)

Family Cites Families (13)

• 2000
  • 2000-04-28 DE DE10020878A patent/DE10020878C2/de not_active Expired - Fee Related
• 2001
  • 2001-03-15 CN CNB018087728A patent/CN1180184C/zh not_active Expired - Fee Related
  • 2001-03-15 DE DE50107752T patent/DE50107752D1/de not_active Expired - Fee Related
  • 2001-03-15 JP JP2001580982A patent/JP2003532026A/ja active Pending
  • 2001-03-15 EP EP01938021A patent/EP1276994B1/fr not_active Expired - Lifetime
  • 2001-03-15 AT AT01938021T patent/ATE307294T1/de not_active IP Right Cessation
  • 2001-03-15 WO PCT/EP2001/002943 patent/WO2001083994A1/fr active IP Right Grant
  • 2001-03-15 US US10/258,787 patent/US6814542B2/en not_active Expired - Fee Related

Non-Patent Citations (1)

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