Cooling fan assembly
A fan assembly includes two or more axial flow fans rotatably mounted on a support structure. The fans are of the adjustable pitch type, i.e., each fan includes a pitch adjustment mechanism that is actuatable by axially shifting a positioning rod extending outward from the hub of the fan. The assembly further includes a control member and a plurality of adjustment mechanisms coupled respectively to the positioning rods and to the control member in such a way that the position of the control member determines the axial position of the positioning rods and thereby the pitch of the blades of all the fans of the assembly. A single actuator is configured to actuate a movement of the control member.
1. A cooling fan assembly comprising:
a support structure;
a plurality of cooling fans, each fan comprising:
(i) an axle that is rotatable with respect to the support structure;
(ii) a hub that is uniform with or fixed to the axle;
(iii) blades extending outward radially with respect to the hub, wherein a pitch of the blades is adjustable by pivoting the blades about respective radial axes;
(iv) a mechanism mounted in the hub, for simultaneously adjusting the pitch of the blades; and
(v) a positioning rod oriented and movable in an axial direction of the fan, partially extending out of the hub, and coupled to the mechanism in such a way that an axial position of the positioning rod determines the pitch of the blades of the fan;
an actuator;
a control member that is movable relative to the support structure, and that is furthermore coupled to the actuator, so that the actuator is configured to drive a movement of the control member; and
a plurality of adjustment mechanisms, one for each fan, wherein each of the plurality of adjustment mechanisms is coupled to the positioning rod of a respective one of the plurality of cooling fans and to the control member, in such a way that movement of the control member simultaneously sets the axial position of each positioning rod and thereby the pitches of the blades of the plurality of cooling fans.
2. The cooling fan assembly according to claim 1 , wherein the control member is an elongate member that is either rotatable about its central axis or axially displaceable.
3. The cooling fan assembly according to claim 2 , wherein the control member is a control rod that is rotatable about its central axis, and wherein the actuator is configured to drive the rotation of the control rod.
4. The fan assembly according to claim 3 , wherein each of the plurality of adjustment mechanisms is a crank mechanism, and wherein each crank mechanism comprises a crank arm and a connecting arm, the connecting arm being coupled to the positioning rod of a respective one of the plurality of cooling fans, so that the crank mechanism is configured to drive the axial movement of the positioning rod of the respective one of the plurality of cooling fans by rotating the crank arm.
5. The fan assembly according to claim 3 , wherein the control rod comprises a lever and wherein the actuator is coupled to the lever.
6. The fan assembly according to claim 5 , wherein the actuator is a motor comprising a rotatable outlet axle and wherein the axle is coupled to the lever by a crank mechanism.
7. The fan assembly according to claim 6 , wherein the motor is an electric motor.
8. The fan assembly according to claim 3 , wherein:
the control rod is a main control rod that is directly coupled to one or more of the plurality of adjustment mechanisms configured to displace the positioning rods of one or more first fans of the plurality of cooling fans,
the fan assembly further comprises an additional control rod that is directly coupled to one or more further ones of the plurality of adjustment mechanisms configured to adjust the blades of one or more second fans of the plurality of cooling fans placed at a different height level than the one or more first fans, and
the main control rod and the additional control rod are coupled by a mechanical transmission configured so that movement of the main control rod drives a movement of the additional control rod.
9. The fan assembly according to claim 3 , wherein the control rod is axially displaceable along its central axis, and wherein the actuator is configured to drive an axial movement of the control rod.
10. The fan assembly according to claim 9 , wherein the actuator is configured to drive the axial movement in one direction only, and wherein movement in the opposite direction is actuated by one or more springs.
11. The fan assembly according to claim 1 , wherein the control member is a single member to which the plurality of adjustment mechanisms is directly coupled, in a sense that each of the plurality of adjustment mechanisms comprises a component that is fixed to or uniform with the control member.
12. The fan assembly according to claim 1 , wherein a phase difference between the pitch of the blades of at least two of the plurality of cooling fans is different from zero.
13. The fan assembly according to claim 1 , wherein at least two of the plurality of cooling fans have different diameters.
14. A work machine comprising an internal combustion engine equipped with a radiator and with a cooling fan assembly according to claim 1 , arranged to produce a flow of air for cooling a liquid coolant flowing through the radiator.
15. The work machine according to claim 14 , wherein the work machine is a combine harvester, a forage harvester, a cotton harvester or a sugar cane harvester.