CN110630536A

CN110630536A - Fan and electromechanical assembly and method thereof

Info

Publication number: CN110630536A
Application number: CN201810650766.2A
Authority: CN
Inventors: C·S·帕特尔; S·B·戴塔尔; U·M·萨瓦卡; L·陈
Original assignee: Lei Bo U S Co
Current assignee: Lei Bo U S Co
Priority date: 2018-06-22
Filing date: 2018-06-22
Publication date: 2019-12-31

Abstract

A fan for an electric motor having a shaft and an axis of rotation includes a base plate including a front surface, a rear surface, and a hub configured for coupling to the shaft. The fan also includes a plurality of circumferentially spaced primary blades extending a first radial length from the hub along the front surface, and a plurality of circumferentially spaced secondary blades extending a second radial length from the hub along the front surface. The second radial length is less than the first radial length.

Description

Fan and electromechanical assembly and method thereof

Technical Field

The field of the invention relates generally to fans, and more particularly to cooling fans for motor assemblies.

Background

Many known electrical machines, such as electric motors/motors, generate heat during operation. At least some known motors are provided with a cooling fan rotatably coupled thereto, and the fan rotates during operation of the motor to generate an airflow over the motor housing to facilitate motor cooling. However, at least some known fans cause insufficient airflow, which can produce undesirable motor cooling effects, particularly at the opposite end of the motor from the fan.

Disclosure of Invention

In one embodiment, a fan for an electromechanical assembly having a shaft and an axis of rotation is provided. The fan includes a base plate including a front surface, a rear surface, and a hub configured for coupling to the shaft. The fan also includes a plurality of circumferentially spaced primary blades extending a first radial length from the hub along the front surface, and a plurality of circumferentially spaced secondary blades extending a second radial length from the hub along the front surface. The second radial length is less than the first radial length.

In another embodiment, an electromechanical assembly is provided. The electromechanical assembly includes a housing and a motor located within the housing and including a shaft having an axis of rotation. The electromechanical assembly also includes a fan coupled to the shaft and including a base plate having a front surface, a rear surface, and a hub coupled to the shaft. The fan also includes a plurality of circumferentially spaced primary blades extending a first radial length from the hub along the front surface, and a plurality of circumferentially spaced secondary blades extending a second radial length from the hub along the front surface. The second radial length is less than the first radial length.

In yet another embodiment, a method of assembling an electromechanical assembly is described. The method includes forming a base plate including a front surface, a rear surface, and a hub configured for coupling to a rotating element. The method also includes forming a plurality of circumferentially spaced apart primary blades on the base plate, wherein the primary blades extend a first radial length from the hub along the front surface. The method also includes forming a plurality of circumferentially spaced secondary blades on the base plate. The secondary blade extends from the hub along the front surface a second radial length that is less than the first radial length.

Drawings

FIG. 1 is a perspective view of an exemplary electromechanical assembly;

FIG. 2 is a cross-sectional view of the electromechanical assembly shown in FIG. 1;

FIG. 3 is a perspective view of an exemplary fan for use with the electromechanical assembly shown in FIG. 1;

FIG. 4 is a front view of the fan shown in FIG. 3;

FIG. 5 is a rear view of the fan shown in FIG. 3; and

FIG. 6 is a cross-sectional view of the fan taken along line 6-6 in FIG. 4.

Detailed Description

The methods and systems described herein facilitate providing a radial fan for cooling a rotating device, such as a motor. The fan includes a base plate including a front surface, a rear surface, and a hub configured for coupling to a shaft. The fan also includes a plurality of circumferentially spaced primary blades extending a first radial length from the hub along the front surface, and a plurality of circumferentially spaced secondary blades extending a second radial length from the hub along the front surface, wherein the second radial length is less than the first radial length. The secondary blades serve to bifurcate the airflow between adjacent primary blades to reduce turbulence and smoothly direct the airflow exiting the fan. Furthermore, the profile of the secondary blade has an apex (apex) that prevents mixing of the air streams between the two primary blades. In addition, the predetermined second radial length of the secondary blades is designed to allow the highest airflow velocity exiting the fan case and flow rate along the motor housing, the highest non-drive end airflow velocity, and the highest percentage of air volume directed into the slots (sumps) formed in the housing.

Fig. 1 shows a perspective view of an exemplary embodiment of an electromechanical assembly 10, and fig. 2 is a cross-sectional view of the electromechanical assembly 10. In the exemplary embodiment, electric machine assembly 10 includes a housing 12 and a motor 14 positioned within housing 12. The housing 12 includes a first end wall 16, a second end wall 18, and a side wall 20 extending from the first end wall 16 to the second end wall 18. In one embodiment, the housing 12 is generally cylindrical and includes a slot 22 in the sidewall 20. In other embodiments, the housing 12 may be any suitable shape that enables the electromechanical assembly 10 to function as described herein. In the exemplary embodiment, a plurality of cooling fins 24 protrude from side wall 20 and are oriented substantially from first end wall 16 to second end wall 18 along a length of housing 12. In alternative embodiments, the cooling fins 24 may extend along only a portion of the housing 12 or may not be present at all.

In the exemplary embodiment, motor 14 includes a rotating shaft 26 having a first end 28, a second end 30, and an axis of rotation 32 oriented from first end 28 toward second end 30. The shaft 26 extends through the first end wall 16 of the housing 12 such that a first end 28 of the shaft 26 is exposed outside of the housing 12 for coupling to a load (not shown). The shaft 26 also extends through the second end wall 18 such that a second end 30 of the shaft 26 is exposed outside of the housing 12 for coupling to a fan 34 to facilitate generating a cooling air flow over the cooling fins 24 of the housing 12 for cooling the motor 14, as described herein.

The electromechanical assembly 10 also includes a generally bowl-shaped fan shroud 36 fixedly coupled to the second end wall 18 of the housing 12 such that the fan shroud 36 is disposed above the fan 34, the fan 34 rotatably coupled to the second end 30 of the shaft 26 and axially between the fan shroud 36 and the second end wall 18 of the housing 12. The fan shroud 36 helps to protect the fan 34 and improve cooling performance along the housing 12. In the exemplary embodiment, fan casing 36 includes a central section 38 of fan casing 36 that is oriented substantially perpendicular to rotational axis 32, and an outer peripheral portion 40 of fan casing 36 that is substantially parallel to rotational axis 32. The central section 38 and the peripheral section 40 are joined together by an inclined portion 42.

In the exemplary embodiment, central section 38 includes a plurality of air inlets 44 that are oriented substantially parallel to rotational axis 32. Alternatively, inlet 44 may have any size, orientation, and shape that facilitates operation of fan casing 36 as described herein. The fan housing 36 is sized to envelope at least a portion of the second end wall 18 of the housing 12 to define an annular air outlet 46 defined radially between the fan housing 36 and the housing 12 along the side wall 20 of the housing 12. In one embodiment, the outlet 46 is shaped to help direct a maximum amount of cooling airflow through the outlet 46 and over the sidewall 20 such that the air exits the outlet 46 substantially parallel to the axis 32. In other embodiments, the outlet 46 may be shaped in any suitable manner.

In the exemplary embodiment, motor 14 includes a rotor 48 and a stator 50 positioned within sidewall 20. The rotor 48 and stator 50 generate heat during operation and are cooled by air flowing through the second end wall 18 and through the cooling fins 24 across the side wall 20. Specifically, the cooling fins 24 are aligned with the outlets 46 to facilitate cooling of the motor 14.

FIG. 3 is a perspective view of the fan 34 for use with the electromechanical assembly 10, FIG. 4 is a front view of the fan 34, FIG. 5 is a rear view of the fan 34, and FIG. 6 is a cross-sectional view of the fan 10 taken along line 6-6. In the exemplary embodiment, fan 34 is a bi-directional fan that includes a base plate 54 having a hub 56, an outer rim 58, a first face 60 that extends from hub 56 to outer rim 58, and an opposite second face 62 that extends from hub 56 to outer rim 58. As described herein, the hub 56 is configured to be coupled to the second end 30 of the shaft 26. In the exemplary embodiment, first face 60 and second face 62 are both perpendicular to axis 32 such that base plate 54 is planar in shape. The flat base plate 54 helps draw a greater amount of air through the inlet 44 and also reduces vibration of the fan 34 to direct airflow perpendicular to the axis 32 toward the angled portion 42 of the fan housing 36 to facilitate directing airflow parallel to the axis 32 at the outlet 46.

The base plate 54 further includes a plurality of holes 63 sized to allow airflow through the base plate 54 to facilitate cooling of the second end wall 18 and other components of the housing 12, such as bearings. The apertures 63 may have any suitable size or shape that facilitates functioning of the fan 34 as described herein. In the exemplary embodiment, aperture 63 is positioned proximate hub 56 on base plate 54.

In the exemplary embodiment, fan 34 also includes a plurality of circumferentially-spaced main blades 64 coupled to first face 60 and extending a first radial length RL1 from hub 56 to rim 58 along first face 60. Each main blade 64 includes a main edge 66 defining a main contour 68 of the main blade 64. The primary edge 66 includes a first section 70 extending from the hub 56 perpendicular to the axis 32, a second section 72 extending obliquely from the first section 70 away from the base plate 54, a third section 74 extending from the second section 72 perpendicular to the axis 32, and a fourth section 76 extending obliquely from the third section 74 to the rim 58. The second and third sections 72 and 74 define an angle α therebetween in the range of about 120 degrees and about 140 degrees. More specifically, in one embodiment, the angle α is about 130 degrees. Similarly, third and

fourth sections

74 and 76 define an angle β therebetween in the range of about 70 degrees and about 90 degrees. More specifically, in one embodiment, the angle β is about 80 degrees.

In addition, the third section 74 defines a maximum first axial length AL1 of each primary vane 64 between the first face 60 and the primary edge 66. Further, each main blade 64 has a circumferential blade thickness T that is constant at a given axial height between the hub 56 and the rim 58, but that tapers between the first face 60 and the main edge 66 such that the blade thickness T is greater proximate the first face 60.

In the exemplary embodiment, fan 34 also includes a plurality of circumferentially-spaced secondary blades 78, secondary blades 78 coupled to first face 60 and extending a second radial length RL2 from hub 56 along first face 60 to a point between hub 56 and rim 58. The second radial length RL2 is less than the first radial length RL1 of the main blade 64. Specifically, second radial length RL2 extends within a range of approximately 65% and 85% of the length of first radial length RL 1. More specifically, second radial length RL2 extends approximately 75% of the length of first radial length RL 1.

Each secondary blade 78 includes a secondary edge 80, the secondary edge 80 defining a secondary profile 82 of the secondary blade 78 that is different from the primary profile 68. The minor edge 80 includes a first section 84 extending obliquely from the hub 56 away from the base plate 54 to an apex 86 and a second section 88 extending obliquely from the apex to the first face 60. In the exemplary embodiment, apex 86 is positioned within a range of approximately 50% to 60% along second radial length RL2 of secondary blade 78. Alternatively, apex 86 is positioned at any point along second radial length RL2 that facilitates operation of fan 34 as described herein. The first section 84 and the second section 88 define an angle γ therebetween in the range of about 115 degrees and about 135 degrees. More specifically, in one embodiment, the angle γ is approximately 125 degrees.

In addition, the apex 86 defines a maximum second axial length AL2 of each secondary blade 78 between the first face 60 and the second edge 80. In the exemplary embodiment, second axial length AL2 is less than first axial length AL1 of main vane 64. Further, each secondary blade 78 has a blade thickness T that is constant along the second radial length RL2 at a given axial height, but that tapers between the first face 60 and the secondary edge 80 such that the blade thickness T is greater proximate the first face 60. The blade thickness T is substantially similar for the primary blade 64 and the secondary blade 78.

In the exemplary embodiment, primary blades 64 and secondary blades 78 are alternately circumferentially spaced and oriented substantially radially from hub 56 toward outer rim 58 and project substantially perpendicularly from first face 60 of base plate 54 to respective primary edge 66 or secondary edge 80 such that primary blades 64 and secondary blades 78 are radially linear. In this manner, the fan 34 is an axial fan configured for bi-directional operation.

In the exemplary embodiment, fan 34 also includes a plurality of ribs 90 that extend from second face 62 of base plate 54. Each rib 90 also extends generally radially from hub 56 toward outer rim 58 and has a third radial length RL3 that is greater than second radial length RL2 and less than first radial length RL 1. Further, each rib 90 projects substantially perpendicularly from the second face 62 and is generally aligned with a respective one of the secondary blades 78. Alternatively, each rib 90 is oriented at any angle between 0 ° and 90 ° from the second face 62 of the base plate 54. In addition, the ribs 90 are substantially planar. Alternatively, each rib 90 may have any curvature that enables fan 34 to function as described herein when ribs 90 extend from base plate 54 and/or when ribs 90 extend between hub 56 and rim 58.

During operation, the fan 34 rotates about the axis of rotation 32 and draws air in through the air inlet 44 of the fan housing 36. The combination of the radially flat main blades 64 and the flat base plate 54 helps to direct air perpendicularly with respect to the axis of rotation 32 as it passes over the outer rim 58 and then axially along the housing 12 and the cooling fins 24 extending therefrom through the outlet 46 by the fan shroud 36.

The secondary blades 78 serve to bifurcate the airflow between adjacent primary blades 64 to reduce turbulence and smoothly direct the airflow exiting the fan 34. Specifically, the secondary profile 82 of the secondary blades 78 increases the suction power of the fan 34 and has an apex 86 positioned and designed to prevent mixing of the airflow between adjacent primary blades 64. The increase in suction power results in a higher air flow velocity at the outlet 46, which provides more efficient cooling of the housing 12, particularly at the opposite, non-driven end, proximate the first end wall 16. More specifically, the relatively high exit velocity is designed to direct the airflow into the slots 22 of the sidewall 20 to promote cooling. In addition, machine 10 with fan 34 results in a more uniform air flow around housing 12, resulting in efficient cooling of motor 14.

In addition, the second radial length RL2 of secondary vane 78 is designed to allow the highest outlet airflow velocity and flow rate, the highest non-drive end airflow velocity, and the highest percentage of air volume directed into slot 22 to be achieved. Thus, in the exemplary embodiment, second radial length RL2 extends within a range of approximately 65% to 85% of the length of first radial length RL1, and more specifically, second radial length RL2 extends approximately 75% of the length of first radial length RL 1.

In addition, the second face 62 creates a low pressure region during rotation of the fan 34 such that airflow through the holes 63 and over the second end wall 18 is increased to promote improved cooling of the bearings of the motor 14 and the region proximate the second end wall 18 (e.g., low pressure gradients due to the base plate 54, the base plate 54 drawing air through the holes 63 (at least in part) due to the bernoulli effect).

The methods and systems described herein facilitate providing a radial fan for cooling a rotating device, such as a motor. The fan includes a base plate having a front surface, a rear surface, and a hub configured for coupling to a shaft. The fan also includes a plurality of circumferentially spaced primary blades extending a first radial length from the hub along the forward surface and a plurality of circumferentially spaced secondary blades extending a second radial length from the hub along the forward surface, wherein the second radial length is less than the first radial length. Technical effects of the apparatus and methods described herein include at least one of: providing a higher air flow rate along the motor housing; reducing air recirculation at the hub of the fan; increasing fluid availability at the non-drive end of the housing to facilitate cooling, reduce noise generation and reduce power consumption; and reduced manufacturing costs due to the planar design of the blade.

This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.

Claims

1. A fan for an electromechanical assembly having a shaft and an axis of rotation, the fan comprising:

a base plate comprising a front surface, a rear surface, and a hub configured for coupling to the shaft;

a plurality of circumferentially spaced main blades extending a first radial length from the hub along the front surface; and

a plurality of circumferentially spaced secondary blades extending a second radial length from the hub along the front surface, wherein the second radial length is less than the first radial length.

2. The fan of claim 1 wherein the plurality of primary blades and the plurality of secondary blades are radially linear.

3. The fan of claim 1, wherein the second radial length extends in a range of approximately 65% to 85% of the first radial length.

4. The fan as claimed in claim 1, wherein the front surface and the rear surface are perpendicular to the rotation axis such that the base plate is flat.

5. The fan of claim 1 wherein each primary blade includes a primary edge defining a primary profile of the primary blade and the secondary blade includes a secondary edge defining a secondary profile of the secondary blade different from the primary profile.

6. The fan of claim 5 wherein the secondary edge includes an inner section extending obliquely from the hub to an apex and an outer section extending obliquely from the apex to the front surface.

7. An electromechanical assembly comprising:

a housing;

a motor located within the housing and including a shaft having an axis of rotation; and

a fan coupled with the shaft, wherein the fan comprises:

a base plate including a front surface, a rear surface, and a hub coupled to the shaft;

8. The electromechanical assembly of claim 7, further comprising:

a fan housing coupled with the housing, wherein an annular outlet is defined between the housing and the fan housing; and

a plurality of cooling fins coupled to the housing, wherein the plurality of cooling fins are aligned with the outlet to facilitate cooling the motor.

9. The electromechanical assembly according to claim 7, wherein each primary blade comprises a primary edge defining a primary profile of the primary blade and the secondary blade comprises a secondary edge defining a secondary profile of the secondary blade different from the primary profile, wherein the secondary edge comprises an inner section extending obliquely from the hub to an apex and an outer section extending obliquely from the apex to the front surface, wherein the inner and outer sections define an angle of between about 115 degrees and 135 degrees.

10. The electromechanical assembly according to claim 7, wherein the second radial length extends about 75% of the first radial length.