EP1865207A2

EP1865207A2 - Fan shroud assembly

Info

Publication number: EP1865207A2
Application number: EP07109608A
Authority: EP
Inventors: Eric B Smith; Jeremy S Van Essen
Original assignee: Deere and Co
Current assignee: Deere and Co
Priority date: 2006-06-05
Filing date: 2007-06-05
Publication date: 2007-12-12
Also published as: BRPI0702794A; CN101085597A; US20070277752A1; EP1865207A3

Abstract

A vehicle has an engine (10) movably mounted on a frame (12), a fan (18) mounted on an engine driven shaft (20), a radiator (16) fixedly mounted on the frame (12), and a hollow shroud assembly (22) which extends from the fan (18) to the radiator (16). The shroud assembly (22) includes an inner shroud member (24), an outer shroud member (26) and a flexible annular seal member (28) which interconnects the inner and outer shrouds (24, 26). The inner shroud member (24) is mounted to the engine (10) and fixed with respect to the engine (10) and the fan (18). The inner shroud member (24) integrally forms an aspirator port (52). The outer shroud member (26) is fixed with respect to the frame (12). The flexible seal member (28) sealingly engages the inner and outer shroud members (24, 26). The seal member (28) has an annular gripping part (32) and an annular lip (34) which projects away from the gripping part (32). The gripping part (32) grippingly engages an end of the outer shroud member (26). The lip (34) engages an outer surface of the inner shroud member (24). The gripping part (32) has a U-shaped cross section and an annular frame (42) with a U-shaped cross section is embedded in the gripping part (32).

Description

The present invention relates to a fan shroud assembly for a vehicle having a frame, an engine movably mounted on the frame, a fan mounted on an engine driven shaft, and a radiator fixedly mounted on the frame.
Commercially available tractors typically include a cooling fan and a fan shroud which at least partially surrounds the fan. The fan is mounted to the engine on an engine driven shaft, and the shroud is normally mounted to the vehicle frame. A certain fan tip to shroud clearance must be maintained for optimum cooling system performance, and to reduce drive-by noise. Some fan shrouds have a pre-cleaner aspirator connection for producing a vacuum which operates a pre-cleaner aspirator. The amount of vacuum will vary if the distance between the pre-cleaner aspirator connection and the fan blade varies - the vacuum will vary if the fan blade is allowed to move or oscillate with respect to the aspirator connection location.
Typically, tractor engines have been rigidly mounted as an integral part of the vehicle frame. However, a rigid engine mount transmits engine noise and vibration into the operator's station or cab. To minimize noise transmission, the engine has been mounted to the tractor frame using elastomer vibration isolators which allow the engine to move relative to the vehicle frame. Since the cooling fan is attached to the engine and the surrounding fan shroud is attached to the frame, any motion or torque of the engine effects the fan tip to shroud clearance and effects the operation of the aspirator connection. It is desired to have a shroud assembly which maintains a fixed fan blade to shroud positional relationship despite movement of the engine relative to the vehicle frame.
By mounting the fan 0.75 diameters away from the radiator, air flow distribution across the radiator is even, though the radiator is rectangular and the fan is circular. Systems where the fan-to-radiator clearance is less than 0.1 fan diameter fail to utilize the corners of the rectangular radiator.
A two-piece fan shroud is used on a production mount log loader. This shroud assembly has shroud part which surrounds an engine driven fan and which is bolted to the engine.
However, this shroud assembly lacks an aspiration port. A seal is installed between the other shroud part and a radiator. But, this seal is designed to withstand a positive internal pressure, and would not be suited to the negative pressure which exits in a tractor fan shroud.
Accordingly, one problem to be solved by this invention is, to provide a shroud assembly for a vehicle which has an engine which is mounted for movement relative to the vehicle frame.
According to the invention this problem will be solved by the teaching of claim 1, wherein a vehicle includes an engine which is movably mounted on a frame. A fan is mounted on an engine driven shaft, and a radiator fixedly mounted on the frame. A fan shroud assembly at least partially surrounds the fan and extends from the fan to the radiator. The shroud assembly includes an inner shroud member, an outer shroud member and a flexible annular seal member which interconnects the inner and outer shrouds. The inner shroud member is mounted to the engine and fixed with respect to the engine and the fan. The inner shroud member integrally forms an aspirator port, wherein the aspirator port is preferably located adjacent the blades of the fan and exposed to negative pressure preferably produced by operation of the fan. The outer shroud member is fixed with respect to the frame. The flexible seal member sealingly engages the inner and outer shroud members.
In a preferred embodiment the seal member has an annular gripping part and an annular lip which projects away from the gripping part. The gripping part grippingly engages an end of the outer shroud member. The lip engages an outer surface of the inner shroud member. The gripping part has a U-shaped cross section and an annular frame with a U-shaped cross section is embedded in the gripping part.
The seal member preferably has a first annular part with a U-shaped cross section and a second annular part which projects generally axially away from the first part, the first part having a rigid annular frame with a U-shaped cross section embedded therein.
In a further embodiment the first part of the seal member comprises radially inner and outer annular rims, and the second part of the seal member comprises an annular lip which projects generally axially away from the rims, an end of one of the shroud members being received between the inner and outer annular rims, and the lip engaging a surface of the other of the shroud members.
Furthermore the seal member may have radially inner and outer annular rims and an annular lip which projects generally axially away from the rims, an end of one of the shroud members being received between the inner and outer annular rims, and the lip engaging a surface of the other of the shroud members.
In another embodiment the seal member may have radially inner and outer annular rims and an annular lip which projects generally axially away from the rims, an end of the outer shroud member being received between the inner and outer annular rims, and the lip engaging a surface of the inner shroud member.
In another embodiment the seal member has an annular gripping part and an annular lip which projects away from the gripping part, the gripping part grippingly engaging an end of one of the shroud members, in particular of the outer shroud member, and the lip engaging an outer surface of the other of the shroud members, in particular of the inner shroud member.
The gripping part may have a U-shaped cross section and an annular frame with a U-shaped cross section is embedded in the gripping part.
The gripping part may receive an end of the outer shroud member and the lip engages an outer surface of the inner shroud member.
One advantage of the invention is that such a shroud assembly maintains a fixed distance between an aspirator port and the fan blades. Furthermore the shroud assembly minimizes variation in the vacuum efficiency of an aspirator port. An additional advantage is that aspirator port is formed as an integral part of the shroud assembly. Furthermore the shroud assembly provides an elastomer seal between the inner and outer shrouds for flexibility and sealing ability.
This and other advantages and features will be described more in detail within the embodiment according to the following drawings, wherein:

Fig. 1: shows a side view of a shroud assembly of the present invention with schematic representation of the engine and frame,
Fig. 2: shows an enlarged sectional view of a portion of Fig. 1,
Fig. 3: shows a perspective view of the fan and the inner shroud of the shroud assembly of Fig. 1,
Fig. 4: shows a sectional side view taken along lines 4-4 of Fig. 3 and
Fig. 5: shows an exploded perspective view of the shroud assembly of Fig. 1.

Referring to Fig. 1, a vehicle such as an agricultural tractor, includes an engine 10 mounted on a frame member 12 with flexible vibration isolators 14. A radiator 16 is rigidly supported on the frame member 12. A fan 18 with a plurality of blades 19 is mounted on an engine driven shaft 20. A hollow shroud assembly 22 partially surrounds the fan 18 and extends between the fan and the radiator 16.
The shroud assembly 22 includes an inner shroud 24 and an outer shroud or plenum 26 which are joined together by an annular seal member 28. The inner shroud 24 includes a cylindrical wall 23 and an annular central stiffening flange 25 which projects radially outwardly from wall 23. Brackets 27 rigidly support radiator 16 on frame member 12. The outer shroud 26 is secured to the radiator 16 with bolts or capscrews (not shown). The inner shroud 24 is rigidly fixed to the engine 10 by a pair of brackets 30, one of which is seen in Fig. 1. The brackets 30 are bolted to attachment members 31 which are integrally formed near the bottom portion of inner shroud 24. As a result, the space or clearance between the blades 19 of the fan 18 and the inner surface of inner shroud 24 remains fixed, since the engine 10, fan 18 and inner shroud 24 all move together when the engine 10 vibrates with respect to the frame member 12. In addition to the lower brackets or engine mounts 30, upper brackets 33 to support the inner shroud 24 with respect to the engine 10.
As best seen in Fig. 2, the flexible seal member 28 has an annular gripping part 32 and an annular lip 34 which projects axially away from a radially outer portion of the gripping part 32. The gripping part 32 has a U-shaped cross sectional shape formed by an inner wall or rim 36, outer wall or rim 38 and bight portion 40. A rigid frame member 42 with a U-shaped cross section is embedded in the gripping part 32. The frame member 42 is rigid, but is flexible enough to create a spring force so that it grips the outer shroud 26.
Wall 36 has an annular sealing flap 44 on its inner surface, and wall 38 has an annular sealing flaps 46 on its inner surface. The gripping part 32 receives the forward end of the outer shroud 26 so that the flaps 44 and 46 make contact with the surfaces of the outer shroud 26. The flexible annular lip 34 sealingly engages an outer surface of the inner shroud 24.
The suction produced by the fan 18 helps cause the lip 34 of the seal member 28 to stay in sealing contact with inner shroud 24, and thus seal member 28 maintains a substantially airtight seal between the inner shroud 24 and the outer shroud 26 despite relative movement therebetween. The annular flaps 44 and 48 do not seal, but supply gripping surfaces to restrain the seal 34 to the shroud 26.
The seal is preferably approximately 44 millimeters wide and is held in place without any special fasteners or adhesives due to the U-shaped rigid frame embedded in the sealing member 28. As fan speed increases, so does the sealing effect of the sealing member 28, which is necessary due to the torque of the engine 10 causing misalignment between the inner shroud 24 and the outer shroud 26.
As best seen in Figs. 3 and 4, an aerodynamic port structure 50 is integrally formed in the inner shroud 24 close to the area occupied by the blades 19 of the fan 18. An opening or port 52 extends through the port structure 50. The operation of the fan 18 will draw air in through the port 52. Port 52 may be connected by an air hose (not shown) to a device which requires aspiration, such as an engine air pre-cleaner (not shown). Because the space or clearance between the fan blades 19 and the inner shroud 24 remains fixed, there will be a fixed clearance between the port structure 50 and the fan blades 19, and there will be a constant amount of vacuum produced at port 52 at fixed fan speeds. This minimizes variation in the vacuum efficiency of the device being aspirated by port 52.
As best seen in Fig. 5, the sealing member 28 has a two-piece construction with two halves 60 and 62, and the outer shroud 26 has a two-piece construction with two halves 64 and 66.
While the present invention has been described in conjunction with a specific embodiment, it is understood that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, this invention is intended to embrace all such alternatives, modifications and variations which fall within the spirit and scope of the appended claims.

Claims

A fan shroud assembly (22) for a vehicle having a frame (12), an engine (10) movably mounted on the frame (12), a fan (18) mounted on an engine driven shaft (20), and a radiator (16) fixedly mounted on the frame (12), characterized in that the fan shroud assembly (22) comprises an inner shroud member (24) mounted to the engine (10) and fixed with respect to the engine (10) and the fan (18), wherein the inner shroud member (24) at least partially surrounding the fan (18) and having an aspirator port (52) exposed to negative pressure produced by operation of the fan (18), an outer shroud member (26) fixed with respect to the frame (12) and an elastomer annular seal member (28) sealingly engaging the inner and outer shroud members (24, 26), and that the fan shroud assembly (22) extending from the fan (18) to the radiator (16).
The fan shroud assembly (22) of claim 1, wherein the seal member (28) has a first annular part (32) with a U-shaped cross section and a second annular part which projects generally axially away from the first part, the first part having a rigid annular frame with a U-shaped cross section embedded therein.
The fan shroud assembly of claim 1 or 2, wherein the first part of the seal member (28) comprises radially inner and outer annular rims (36, 38), and the second part of the seal member comprises an annular lip (34) which projects generally axially away from the rims (36, 38), an end of one of the shroud members (24, 26) being received between the inner and outer annular rims (36, 38), and the lip (34) engaging a surface of the other of the shroud members (36, 38).
The fan shroud assembly (22) according to one of the foregoing claims 1 to 3, wherein the seal member (28) has radially inner and outer annular rims (36, 38) and an annular lip (34) which projects generally axially away from the rims (36, 38), an end of one of the shroud members (24, 26) being received between the inner and outer annular rims (36, 38), and the lip (34) engaging a surface of the other of the shroud members (36, 38).
The fan shroud assembly (22) according to one of the foregoing claims 1 to 4, wherein the seal member (28) has radially inner and outer annular rims (36, 38) and an annular lip (34) which projects generally axially away from the rims (36, 38), an end of the outer shroud member (26) being received between the inner and outer annular rims (36, 38), and the lip (34) engaging a surface of the inner shroud member (24).
The fan shroud assembly (22) according to one of the foregoing claims 1 to 5, wherein the seal member (28) has an annular gripping part (32) and an annular lip (34) which projects away from the gripping part (32), the gripping part (32) grippingly engaging an end of one of the shroud members (24, 26), and the lip (34) engaging an outer surface of the other of the shroud members (24, 26) .
The fan shroud assembly (22) according to claim 6, wherein the gripping part (32) has a U-shaped cross section and an annular frame (42) with a U-shaped cross section is embedded in the gripping part (32).
The fan shroud assembly (22) of claim 6 or 7, wherein the gripping part (32) receives an end of the outer shroud (26) member, and the lip (32) engages an outer surface of the inner shroud member (24).