JPS60209698A - Vatiable pitch axial flow fan - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION BACKGROUND OF THE INVENTION (a) Field of the Invention The present invention is used for commercial, single-channel and institutional heating, ventilation and air conditioning where it is desirable to vary the volume of air driven by a fan. Regarding fans. More particularly, the present invention relates to a variable pitch axial fan having a plurality of blades extending radially outward from a central angle.

The pitch of the vanes is adjustable to accommodate various air volumes.

(B) Description of the Prior Art In a conventional variable pitch axial flow fan, blade pitch control is performed by a mechanical linkage upstream of the hub of the fan. One type of pitch-controlled blade axial fan is U.S. Pat. No. 42,495 for the Troller.
．． 433. The Toro 2 patent describes a control lever that extends into the fan duct and is movable within the duct by means of a series of linkages and levers that adjust the pitch control of the fan.

Since the fan must rotate relative to the lever,
Relatively large bearings are required to allow rotation of the fan relative to the control linkage. Other types of controllable pitch fans use large ball bearings which are then fed by links to the center of a large lever in front of the fan.

An external actuator moves an arm connected to the bar to create the desired axial movement of the arm. Axial movement of the arm adjusts the pitch of the vanes by a series of mechanical linkages.

Prior art fans are disadvantageous for several reasons. Relatively large bearings are required between the actuating mechanism and the rotating fan section, and the bearings are subject to wear. In this way, the fan is periodically disassembled and
Bearings must be repaired, resulting in expensive maintenance and expensive machine downtime. Mechanical linkage hair 5
One drawback is that after numerous movements of the 5 mechanical linkages.

Link connections tend to loosen and have significant play, resulting in inaccurate pitch adjustment link connections requiring repairs. A further disadvantage of pitch controllable fans with mechanical linkages is that the linkage requires a large number of parts, thus resulting in a relatively expensive pitch control mechanism that is difficult and time consuming to assemble. .

The mechanical linkage of conventional joint control mechanisms requires regular maintenance, including lubrication. When pitch-controlled pre-fans are used for ventilation with 1lJeN as facilities, for example in hospitals or large buildings, lubricant particles get mixed into the air when it is driven over the top of the building. It may be distributed among It would be desirable to eliminate lubricated linkages that are exposed to the air being circulated past the fan.

(C) Summary of the Invention A fan according to the invention includes a pitch control mechanism having a piston element and a cylinder arm that rotate together with the hub of the fan. One of these elements is capable of reciprocating and axial movement, while the other is rigidly fixed against axial movement relative to the hub. The axially staggered elements are connected to each vane by a mechanical linkage, so that axial movement of the staggered strands is translated into pivoting interlocking of the vanes. One blade pitch is selected by controlling the piston and cylinder elements.

In accordance with one aspect of the invention, the piston element is fixed against axial movement with respect to the nozzle, and the cylinder moves axially relative to the hub, which rotates with the nozzle. The connecting linkage includes a cam fixed to the axially reciprocating cylinder element;
It also includes an annular groove having camming surfaces on the first and second sidewalls. Each vane has an axle in which the shaft neck is supported in the rotating blade, and a lever arm is fixed to one end of the one-vane axle. A cam follower is attached to the other end of the lever arm and is located within the annular groove.

While the cylinder moves axially in one direction, the camming surface of the first side wall moves the cam follower, which in turn moves in zero direction.

Suppose you want to pivot the vane axle in one direction l'? −・
Pivot the arm. When it is desired to change the pitch of the vanes, the cylinder is moved to the opposite side.

The camming surface of the second sidewall also moves the cam follower in the opposite direction, and the cam follower then moves the lever to pivot the vane axle in the opposite direction.
Pivot the arm.

According to another aspect of the invention, the piston and cylinder elements are actuated by an air supply IC attached to the pitch control assembly by a pneumatically powered rotary union containing a small bearing. Since the air supply system is relatively vC controlled, the bearings required to support it are small and maintenance is easy. In this way, there is no need for large bearings to support the load of the VC heavy linkage, in contrast to fans according to the prior art.

Since the bearings are small and lightweight, their maintenance is easy. Because the loads are light, the possibility of damage is minimal, and if failure were to occur, the large vibrations that could result in damage to the shaft of the motor driving the fan and control assembly are minimized. It will not spill.

The pitch controllable fan according to the present invention has several desirable advantages. The simplicity of pitch control loading reduces the number of parts required and also eliminates the need for lever bars, large springs, and external actuators and numerous other mechanical components found in traditional pitch controllable fans. Avoiding link connections. By avoiding external and moving actuators, typically located upstream of the fan, the dimensions of the bearing between the actuator and the fan can be reduced considerably. Bearing dimensions and By reducing the load on the bearings, the fan according to the invention is more reliable and has a longer lifespan.

Because the entire pitch control assembly, including the piston and cylinder, rotates with the motor shaft, there is no need for large bearings as in other conventional pitch controllable fans. In this way, one essential moving part that requires continuous maintenance and lubrication is eliminated. The air supply is secured in an assembly with a small rotary union with relatively small bearings. Since the load on the bearing is light, the possibility of breakage is minimal. If this small bearing is broken, #Jμ will not cause damage to the drive motor shaft because the air supply device is lightweight. It does not cause significant vibrations like wax.

The fan according to the invention is designed so that little or no thrust is exerted on the motor shaft when the blade pitch is changed. This is in contrast to fans using conventional lever-type controls that place a significant thrust load on the motor shaft during each blade pitch adjustment. Because thrust loads are minimized or completely avoided, thrust loads are not transferred to the motor bearings and shorten their life. Because the control assembly does not rely on a ring mechanism that can wear out.

The blade adjustment is very precise and precise.

Further advantages of the pitch controllable fan will be apparent from the following detailed description of the invention, taken in conjunction with the accompanying drawings.

B) Detailed Description of the Preferred Embodiment With reference to FIG. 1, a fan according to the invention is shown. The fan includes a generally cylindrical duct secured within the duct structure. As shown in Figure 1, the duct is supported above the floor by legs 14, but it can be positioned in a variety of widely varying positions, including vertical and diagonal positions. The fan includes a motor 16 for driving a motor shaft 18, the motor shaft 18 comprising:
The supporting hub 20, which includes the first few radially extending fan blades 22, is then driven. The motor 16 is located within a motor casing 24 that is centrally supported within the duct by a multi-sided bracket 26. The pitch control assembly shown in reference fold 28 is shown below in FIGS.
It will be described with reference to FIG.

The hub 20 is connected to the axle 32 of each fan play 1'22.
includes a plurality of radially extending apertures 30 dimensioned to receive the radially extending openings 30 . The blade and axle 32 are supported in the aperture 30 of the axial hub and are in the position shown in FIG. 6 and in the position shown in FIG.
Pivot between the positions shown. The end of each axle 32 is
Includes a screw 34 that allows a nut 36 to be secured to the lever arm 38 and to the shell 32. lever arm 3
8 moves from the position shown in FIG. 6 to the 1-position shown in FIG. 7, the axle 32 pivots, thus adjusting the pitch of the sillage v22.

It has a central opening 40 for receiving a fitting 42 secured to the motor shaft 18 . The mating portion 42 includes a beveled 1.44, and the inner surface of the central opening 40 of the hub has a beveled 1.00 mm to ensure a tight fit. It is a face. The hub 20 is secured to the fitting part 42 by a plurality of bolts 45,
Only one of them is shown in FIGS. 6 and 17.

With reference to FIGS. 6, 6 and 7, the pitch control assembly 28 will be described below. The assembly includes a piston sleeve 48 and a cylinder element 50.

Cylinder 50 has a cylindrical portion 52 sized to receive piston head 54 of piston 48 .

Piston head 54 has a generally cylindrical circumferential surface 56 having piston rings 60 and 6 therein.
It has a pair of annular grooves 58 for receiving the piston.
Rings 60 and 62 are arranged to seal the piston to the cylinder.

The cylinder 500 chamber 52 has an O-ring 6 on one side.
4 and a series of bolts that hold it in place against the cylinder 50. The opposite end of cylinder chamber 520 is defined by an end cap 66 made integral with the body of cylinder 500. Piston 48 includes a piston shaft 68 that extends through an axial lobe 70 within an integrally formed wholesale cap f66. The shaft 68 is sealed against the opening lower 0 by a cylindrical sealing bushing 72, preferably made of a suitable plastic. The sealing bushing is connected to the piston shaft 68 and the opening T.

``Allows axial movement of the cylinder 5° relative to the piston 48 while prohibiting air leakage between the cylinders.

The piston is secured to the shaft 18 of the drive motor 16 by a bolt 73 that is tightened into the shaft 18. In this way, piston 48 is ensured against any substantial axial movement relative to hub 20. However, the cylinder 50 will not respond to pressure changes within the cylinder chamber 52 on either side of the piston head 54, as described below with reference to FIGS. 6 and 7. The frame also moves in the axial direction.

The piston and cylinder elements are preferably pneumatically actuated, and thus air must be supplied to the cylinders on either side of the piston rim 54 to cause axial movement of the cylinders. Cylinder 50 includes at least one, and preferably two, passages 74 and 76.

These passages are symmetrical about the central axial cliffs 76 of the piston and cylinder elements. Air is supplied to the other end of the cylinder via a central passage 80.

Air is supplied to central passage 80 and passages 74 and 76 by air supply σt82, which is a conventional dual passage rotor seal.
supplied to Rotor seal 82 includes air inlets 84 and 86 that supply air to passageway 80 on the one hand and passageways T4 and 76 on the other hand, respectively. The dual passage rotor seal has a central air supply passage centered on central air passage 80 and includes an annular air supply system centered on passages 74 and 76. The conventional rotor seal used with the fan according to the present invention has relatively small bearings and is easy to maintain.

Each plate 6 has a cylinder frame axially in order to change the axial movement of the cylinder in one direction to the pivoting of the blades.
The mechanism for connecting to 2 will be described below. Cam 90 is fixed to cylinder 50 at the end of the cylinder closest to the hub. The cam includes an annular groove 92 with surfaces 94 and 96 acting as first and second cams. The lever arm 38 for each plate 22 includes a roller 98 rotatably secured to the end of the lever arm.

Roller 98 acts as a cam follower and is sized to fit within an annular 6° #92 and is connected to the first and second
It rests on cam-acting surfaces 94 and 96 on the side walls of.

The operation of the pitch control assembly will now be described with reference to Figures 6 and 7. As shown in FIG. 6, the cylinder 50 is located on the right side of the piston 48 in the air space 100, and on the right side of the piston 48. Feather 22
When it is desired to change the pitch of the air to bII·1, a control mechanism (not shown) guides the air so that it passes through the passage 80.

Create a pressure difference between the chamber to the left of the piston and the chamber to the right of the piston. This pressure difference forces the cylinder to move from the position shown in FIG. 6 to the position 1+IIj shown in FIG. It should be understood that the positioning of the cylinder relative to the piston is controlled to obtain any position intermediate between the positions shown.

This is accomplished by a pressure differential between chambers located on either side of the piston. −
Once the cylinder has been moved to the desired position, the pressure in the chambers on either side of the piston is equalized and maintained as such, so there is no further movement and the cylinder remains in the desired position. will be maintained.

When the piston moves from the position shown in FIG. 6 to the position shown in FIG.
Turning the. Lever 38 in turn pivots axle 32, thereby pivoting vane 22. Blade 22
must pivot in the opposite direction, i.e., when the assembly is shown in FIG. 6
When moved to the position shown, the movement of the piston brings the camming surface 94 of the side wall into contact with the roller, causing the lever to move toward the camber l side. 6th
As shown in the comparison between Fig. 7 and Fig. 7, the cylinder 50 is
Sliding over an aerodynamic cover 102, preferably made of plastic, the cover 102 slopes away from the fan blades 22 toward the outer surface of the cylinder 50. Cover 102 rotates with hub, piston and cylinder lines 48 and 50.

6, a pair of rollers 104 and 106 are secured in the floor of groove 92 by axles 108 and 110 to prevent cylinder 50 from rotating relative to the piston on bush 72. Possibly located. Since the cylinder 50 rests freely on the bushing 72,
It will have a tendency to rotate relative to piston 48 and hub 20. By using stationary rows 2104 and 106, roller 98, which is attached to the lever arm, contacts stationary rollers 104 and 106, inhibiting actual rotation of the cylinder relative to the piston. roller 104
and 106 are preferably located diagonally opposite each other.

The fan according to the invention requires a relatively small number of displacements compared to fans according to the prior art. I! It is a simple t-piece structure with two parts. A pitch control assembly including a piston element and a cylinder line is advantageous over prior art assemblies in that it avoids a complex mechanical coupling between the assembly and the external control. . Since the air supply system f61 using a rotary union is light and short, only a very small load is applied to the bearing. If the bearing should become damaged, it can be easily replaced without thereby damaging or destroying the drive motor. By using a piston and cylinder control assembly, only a small thrust is exerted on the drive motor bearing during pitch adjustment, so the fan will last a long time.

Because the mechanical coupling between the pitch control assembly and the control device on the outside of the duct is eliminated, pitch control is precise and accurate, and this precision is in contrast to mechanical coupling, which tends to wear out. , maintained over the entire life of the fan.

Although specific examples of the invention have been described in detail herein,
Such description is for illustrative purposes only, and modifications may be made thereto by those skilled in the art within the scope of the invention.

[Brief explanation of the drawing]

FIG. 1 is a side perspective view of a controllable pitch fan according to the present invention, with a portion of the duct containing the fan cut away to show a perspective view of the fan and blades; FIG. Figure 6 is an exploded perspective view of the fan shown in Figure 1; Figure 4 is a plan view of the end cap of the cylinder; Figure 5 I'3! l is a plan view of the end of the cylinder; FIG. 6 is a sectional view of the fan through a plane extending radially through the central axis of the fan, and also shows the pitch of the fan blades in one extreme position; and FIG. 7 are the same cross-sectional views as FIG. 6, except that the pitches of the blades are adjusted to extreme positions opposite to those shown in FIG. 6. In the figure, 10...Duct 20...Hub 22...
...Fan blade 28...Gituchi'ilj control assembly 32.
...Axle 38 of each blade... Lever, air 48 ... Piston element 50 ... Cylinder element 58 ... Annular well 68 ... ... Piston shaft 82 ... Air supply device (rotor seal) 90
...Cam 94.96...Surface agent that acts as a cam on the side wall.Hiroshi Asamura

Claims (1)

[Claims] In the il+ fan. a duct having an internal tube; a noope axially movable and rotatable within the internal tube; and a plurality of vanes extending radially from the hub, each vane relative to the hub to adjust the pitch of the vane. mounted for pivotal movement; including a piston element and a cylinder element rotating with said hub, one of said elements reciprocating and axially movable with respect to said hub; It is fixed so that there is no movement in the axial direction with respect to the hub described in ^1j. and converting the axial movement of said reciprocating element in one direction into a pivoting movement of said vane, and the axial movement of said reciprocating element in the opposite direction converting said reciprocating element into a pivoting movement of said vane in the opposite direction; A fan comprising means for connecting said axially reciprocating element relative to said blade for converting motion and thereby controlling blade pitch by actuation of said piston and cylinder elements. (2. The fan according to claim 1; wherein the piston element is fixed to the hub so as not to move in the axial direction. (3) Claim 1. In the fan according to either item 1 or item 2; each blade has an axle whose axial neck is supported in the hub; the connecting device connects the element reciprocating in the axial direction; a cam secured to each vane axle, said cam comprising an annular groove having cam-functioning surfaces in a first side wall and a second side wall; and a lever arm secured to each said vane axle at one prong; Each said lever arm is one
a cam follower located in said annular groove at one end; during movement of said axially reciprocating element' in said one direction, a camming surface of said first wall 11; moving the lever arm to move the cam follower within the groove and pivoting the vane axle in one direction; during movement of the axially reciprocating element in the opposite direction; 2 sidewall cam-acting surfaces move the lever arm to move the cam follower into the station and pivot the vane axle in the opposite direction and thereby adjust the pitch of the vane; Features a fan. (4) The fan of claim 6, wherein the piston includes a generally cylindrical disk having one outer end restrained relative to the cylinder, and the cylinder receives the disk. having a chamber generally cylindrical in size, bounded on either side by an end cap thereon, said piston containing a toner projecting through an opening in one of said caps, said shaft having an axis; 2. A fan, wherein said fan is fixed relative to said hub for directional movement and said shaft is sealed relative to said end cap. (5) The fan according to claim 4, wherein the cam including the annular groove is secured to the screw plate. (6) Permissible The fan according to claim 5, wherein the cam is integral with the cylinder element. (7) A fan according to claim 6, wherein the cylinder has a passageway for allowing fluid to flow into and out of one side of the cylinder, the passageway being located at the center of the cylinder. a second passageway extending axially and supplying fluid to an opposite side of the cylinder, the passageway having an opening recessed a predetermined radial distance from the central opening of the central passageway; A fan with a small percentage. (8) In the fan of claim 7, each said cam follower includes a cylindrical roller mounted for rotation on said lever arm, said roller being mounted on said first side wall of said annular groove. and a camming surface of a second sidewall, the roller being dimensioned to fit between the camming surface of the second sidewall and the roller providing reduced friction between the current groove and the cam follower during pitch adjustment of the vane. A fan. (9) A type of fan comprising a hub rotatable axially within a duct and a plurality of vanes extending radially from the hub, each vane being pivotally mounted relative to the hub to permit pitch control of the vanes. in a pitch control assembly for; comprising a piston element and a cylinder element rotating with the hub, one of said elements being able to move in one axis direction and reciprocating relative to the hub;
The notation element is set such that there is no linear movement relative to the hub; the axial movement of the reciprocating element in one direction is converted into a pivoting movement of the vane in one direction. and axially interlocking the reciprocating elements in the opposite direction to provide for pivoting of the blades in the opposite direction, thereby controlling the blade pitch by actuation of the piston and cylinder elements reciprocating in the axial direction. A pitch control assembly characterized in that an element is connected to each of said vanes. (If %) In the control assembly of claim 9, the coupling device includes a cam fixed to the axially movable element, the cam comprising a first side wall and a second side wall. an annular groove having a surface acting as a cam in the side wall; a lever fixed at one flange to each of said vane axles, said lever arm being located within said annular groove at another flange thereof; a cam follower for moving the cam follower; the cam surface of the first side wall is in front of the axially reciprocating element b; the lever arm to move within the blade axle and pivot the vane axle in one direction so that the fall surface acting as a cam on the second 01!l wall reciprocates in the axial direction; moving the lever arm to move the cam follower in the groove and pivot the vane axle in the opposite direction during rapid movement of the element in the opposite direction, thereby adjusting the pitch of the vane; (11) In a fan: a duct having an internal tube; a hub axially rotatable within the internal tube; a plurality of vanes extending radially from the hub, each vane comprising: said element includes a pneumatically actuated bag that is pivotally mounted relative to said hub to adjust the pitch of the vanes; rotating with said hub; converting axial movement in one direction of said constriction into pivoting in one direction of said vane and converting axial movement in the opposite direction of said element into an opposite direction of said vane; A fan characterized in that it includes a device for connecting said axially reciprocating element to each said blade for converting pivoting in the direction and thereby controlling blade pitch by aerodynamic actuation of the recording element. (12. The fan according to claim 11, wherein the element includes a piston and cylinder interlocking. 03) In the fan; a duct having an internal pipe; an axially rotatable hub including a plurality of vanes extending radially from said hub, each vane having an axle with an axle neck supported in said knob for adjusting the pitch of said vanes; a cam that pivots relative to the hub; includes an annular groove having a cam-acting surface on the i-th wall and the second side wall; including a lever arm for each of said vane axles;
an arm fixed at one end to the vane axle and having at the other end a cam, a follower positioned within the annular groove; and axially reciprocating relative to the hub. a camming surface of the first side wall that moves the cam follower into the groove during axial movement of the cam in one direction; During axial movement of the cam in the opposite direction by pivoting the lever arm to move the vane axle in one direction and adjust the vane axle in one direction, the cam-acting surface of the second side wall is A fan characterized in that the cam follower in the groove is moved to pivot the blade axle in opposite directions, thereby adjusting the pitch of the blades by interlocking the cams. (14) A fan according to claim 16, wherein the device for axially displacing the cam includes a pneumatically actuated piston and cylinder combination.