US3724238A

US3724238A - Rotor mounting

Info

Publication number: US3724238A
Application number: US00124798A
Authority: US
Inventors: C Billot; R Retali; A Mercier
Original assignee: Fives Lille Cail
Current assignee: Fives Lille Cail
Priority date: 1970-03-17
Filing date: 1971-03-16
Publication date: 1973-04-03
Anticipated expiration: 1990-04-03
Also published as: CS155971B2; AU2663071A; BE763695A; DE2112834A1; GB1334612A; ZA711751B; FR2102388A5

Abstract

A rotor is pivotally mounted on the lower end of a drive shaft which is suspended for pendular movement. A flexible coupling connects the rotor to the shaft whereby the rotor may be driven by the shaft upon rotation thereof while being permitted to pivot in respect of the shaft, and an elastic return means interposed between the rotor and the shaft tends to move the rotor opposite to the pivoting movement thereof.

Description

iJite Mates atet 1191 Retali et al.

[54] ROTGR MOUNTING [75] Inventors: Roger Retall', Saint Cloud; Andre Mercler, La Madelene, both of France; Claude Billot, Alger, Algeria [73] Assignee: Fives Lille-Call, Paris, France [22] Filed: Mar. 16, 1971 [21] Appl. No.: 124,798

[30] Foreign Application Priority Data Mar. 17, 1970 France ..7009383 '52 U.S.Cl ..64/ 7,34/-58 s1 InLCl ..F16d3/02 58 Field of Search ....1.....34/'5s; 64/7; 210/366, 367

[ 5 6] References Cited UNITED STATES PATENTS 2,936,894 5/1960 Hertrich "210/366 51 Apr. 3, 1973 Bruenig ..2l0/366 Motycka ..2l0/366 FOREIGN PATENTS OR APPLICATIONS 4l8,607 10/1910 France ..21o 366 102,322 3/1899 Germany ..2l0/366 Primary Exai'ninerl(enneth W. Sprague Attorney-Kurt Kelman [5 7 ABSTRACT in respect of the shaft, and an elastic return means in-- terposed between the 'rotor and the shaft tends to move the rotor opposite to the pivoting movement thereof.

12 Claims, Drawing Figures PATENTEBAPR3 1975 3.724.238

sum 2 OF 4 M D w \MMP IMM m m 5 5 I B 4 I a 2 2 w A J FIG.2

INVENTORS. ROGER RETALI ANDRE MERCIER CLAUDE BILLOT BY Kw KM AGENT PATENTEU APR 3 I975 sum 3 BF 4 FIG.3

49a as INVENTORS. ROGER RETALI ANDRE MERCIER CLAUDE BILLOT BY AGENT PATENTEUAPRS B73 3. 724,238

sum u 0F 4 FIGA v so

' 62' f 70 J E 68 I N VENTORS.

ROGER RETALI ANDRE MERCIER CLAUDE BILLOT BY mm W AGENT ROTOR MOUNTING The present invention relates to an apparatus which comprises a frame support, a vertically extending rotary drive shaft, means for suspending the drive shaft on the frame support for pendular movement in respect thereto, and a rotor mounted on the lower end of the drive shaft. An example of such an apparatus is a centrifugal drier wherein the rotor is constituted by a basket containing the product to be dried.

In conventional apparatus of this type, the rotor is rigidly fixed to its drive shaft causing vibrations which are transmitted to the frame support when the rotor is not perfectly balanced during rotation. Furthermore, when the rotor turns at a critical speed which corresponds to the oscillatory cycle of the suspended assembly, the resulting unbalance causes oscillations of considerable amplitude which subject the frame support to excessive tensions. It is, therefore, of obvious interest to hold down the critical speed as much as possible to reduce these loads on the frame support.

It is a primary object of this invention to reduce the loads transmitted to the bearing support of the drive shaft and, as a consequence, to attenuate the vibrations of the support when the rotor is out of balance, and to lower the critical speed.

The above and other objects are accomplished in accordance with the invention by providing a joint pivotally mounting the rotor on the lower end of the drive shaft. The joint is a flexible coupling connecting the rotor to the shaft whereby the rotor may be driven by the shaft upon rotation thereof while being permitted to pivot in respect of the shaft. An elastic return means is interposed between the rotor and the shaft and tends to move the rotor opposite to the pivoting movement thereof.

The flexible coupling and the elastic return means may be combined into a unitary system.

According to one feature of the present invention, the elastic return means comprises two coupling plates respectively fixed to the rotor and the shaft, and an elastically deformable device mounted between the plates whereby one of the plates may be displaced angularly in respect of the other plate. The elastically deformable devicemay be an annular member or a series of annularly disposed blocks of deformable material, such as rubber, or an annular spring or a series of annularly disposed springs interposed between the coupling plates.

According to another feature of this invention, a damping device may be associated with the elastic return means to restrain the oscillations of the rotor in respect to the drive shaft and to oppose the change of direction of the axis of the shaft-rotor assembly so as to limit the amplitude of this change of direction to an admissible value. The damping device is interposed between the drive shaft and the rotor for restraining the pivoting movements of the rotor and may comprise a transverse element, such as an annular disk coaxial with the shaft, mounted on the shaft for gliding and angular movement in respect of the axis of the drive shaft, and clamping means, such as a pair of clamps, fixed on the rotor and clampingly engaging the transverse element, such as by engaging the disk between the clamps.

In certain machines and for certain purposes, it is necessary or desirable to hold the axis of the rotor fixed during rotation thereof. This is particularly true for centrifugal driers with a cylindrical basket from which the dried product is removed by means of a scraper mounted on a fixed support. To prevent the scraper from damaging the filter cloth or screen covering the wall of the basket, the basket must be restrained from oscillating during this operation. Accordingly, a centering device may be mounted on the drive shaft to permit the pivotal movements of the rotor in respect of the drive shaft in an inoperative condition of the centering device but to maintain the rotor and shaft coaxial in its operative condition.

In a preferred embodiment, the centering device comprises a pair of complementary and interengageable conical members, one glidingly mounted on the drive shaft for movement in an axial direction and the other fixed to the rotor. Pressure fluid operated means moves the one conical member from the inoperative condition of the device wherein the members are out of engagement into the operative condition wherein the one conical member engages the other conical member.

Similarly, a damping and centering device may be provided for restraining or preventing pendular movement of the drive shaft in respect of the frame support.

The above and other objects, advantages and features of the present invention will become more apparent from the following detailed description of certain now preferred embodiments thereof, taken in con junction with the accompanying drawing wherein:

FIG. 1 is a side elevational view, primarily in axial section, of a centrifugal drier constructed according to this invention;

FIG. 2 is a like view of another embodiment of a centrifugal drier;

FIG. 3 is a partial axial section showing yet another embodiment of the mounting of the basket of the drier on its drive shaft, as well as compensating and centering devices controlling the relative movement between basket and shaft; and

FIG. 4 is another partial axial section showing a centering device associated with the support of the drive shaft on its bearing support.

Referring now to the drawing and first to FIG. 1, there is shown a cylindrical basket 10 of a centrifugal drier, which basket is suspended on frame support 14 for pendular movement. The basket constitutes the rotor of the illustrated apparatus and the rotor mounting includes a vertically extending drive shaft 12 having a lower end, and a swivel or ball-and-socket joint 13 pivotally mounting the basket 10 on the lower end of the drive shaft. The center of the spherical joint is posi tioned on the axis of the drive shaft and at or near the center of gravity of the basket. The joint includes a flexible coupling of a generally known type which connects the basket to the shaft whereby the basket may be driven by the shaft upon rotation thereof while being permitted to pivot about joint 13 in respect of the shaft.

This flexible coupling is shown to comprise

twocoupling plates

16, 17 respectively fixed to hub 24 of basket 10 and drive shaft 12, and an elastically deformable annular member 15 mounted between the plates whereby one of the plates may be displaced angularly in respect of the other plate in respect of the shaft axis. The annular member 15 may be of rubber, for instance, and could be readily replaced by an equivalent elastically deformable device, such as a series of annularly disposed rubber blocks or springs. Furthermore, this device constitutes an elastic return means interposed between the basket and the shaft and tending to move the basket opposite to the pivoting movement thereof so as to maintain the basket and shaft coaxial to each other.

The upper end of drive shaft 12 is suspended on the frame support 14 for pendular movement in respect thereto. This suspension includes a hemispherical balland-

socket joint

19, 20 consisting of a dished bearing support 20 mounted on the frame support and a complementary bearing race 19 mounted on the dished support for swivel motion in respect thereto,'the dished support having a central bore through which the hearing race extends, and roller bearings 18 supporting the drive shaft 12 in bearing race 19.

The pendular movement of the drive shaft about the joint is damped by an elastic return means constituted by an elastic device 21, similar to the device 15, interposed between the bearing race 19 and an annular flange l 1 fixed to the bearing support 20.

A drive motor 23 is mounted atop of the frame support 14 by means of bracket 29. An output shaft 31 extends from the motor and is coupled to the upper end of the drive shaft for rotating the drive shaft. The illustrated coupling between the motor shaft 26 having a fixed axis and the drive shaft 12 having a pendular axis consists of a flexible coupling 22 of a known type whose center coincides with the center of ball-

andsocket joint

19, 20.

In the modified centrifugal drier of FIG. 2, like reference numerals have been used to designate like parts operating in a like manner to obviate redundancy in the description. This figure shows the position of the basket and the drive shaft 12' when the assembly rotates at great speed and the basket is out of balance. In this embodiment, the mounting of the drive shaft differs from that of FIG. 1.

As shown, a universal joint 25 connects the upper end of drive shaft 12 for pendular movement to the lower end of motor shaft 26 having a fixed axis. The motor shaft is rotatably journaled in bearing 28 mounted atop the frame support 14. The motor shaft is coupled to the motor 23 by coupling 27 which may be rigid. Obviously, the universal joint 25 may be replaced by any type of joint permitting the drive shaft to be angularly displaced in respect of the fixed axis of the motor shaft to permit pendular movement of the drive shaft, such angular displacement being illustrated in FIG. 2, the drive shaft 12' being inclined in respect of motor shaft 26 and basket 10 being inclined in respect of drive shaft 12. In this manner, the center of gravity of the basket may be positioned in the fixed axis of motor shaft 26' without exerting a substantial load on motor shaft bearing 28.

In the embodiment of FIG. 3, there is provided between the basket 10 and the drive shaft 12" not only a flexible coupling and an elastic return means, as in the abovedescribed embodiments, but also a centering device capable of maintaining the basket and drive shaft coaxial in respect of each other, when necessary, as well as a compensating device for restraining the oscillations of the basket in respect of the drive shaft.

As in the previously described embodiments, the basket 10' is mounted pivotally on drive shaft 12" by means of a ball-and-socket joint 13'. In this embodiment, however, the flexible coupling connects the basket and the drive shaft for common rotation by a gear including a collar 38 fixed to the drive shaft and a collar 39 fixed to the hub of the basket. The two collars have interengaging teeth 31 curved in an axial direction so as to permit angular displacement of one collar in respect of the other collar in respect of the drive shaft axis while remaining engaged. An annular crankcase 37 is mounted on collar 38 and contains a lubricating medium 36 wherein the gear teeth 31 are immersed.

The elastic return means of the flexible coupling is constituted by a series of springs 40 annularly disposed between the

flanges

38a, 39a of the collars. The coupling is protected by a fluid-tight cover 41 placed thereover and receiving the drive shaft through a central bore in the cover, and a flexible membrane 42 interconnecting the lower ends of the collars.

The centering device comprises a female conical hub member 45 fixed to the basket and a complementary male conical member 43 glidingly mounted on the drive shaft for movement in an axial direction into and out of engagement with the conical hub member 45. The male conical member 43 is normally pressed axially downwardly out of engagement with the conical hub member 45 by spring 44 engaging shoulder 44a on drive shaft 12 and a shoulder in the conical member 43, respectively.

The illustrated means for moving the conical member 43 from the shown inoperative condition of the centering device wherein the conical members are out of engagement into the operative condition wherein the conical member 43 engages the conical hub member 45 is pressure fluid operated. It includes an annular pressure chamber 47 defined between conical member 43 and a flexible membrane 48 fluid tightly clamped along its annular periphery between the member 43 and a flange 46. The central portion of the membrane 48 is supported on an annular platform 49 fixed to the drive shaft 12' and forming a fluid tight seal with the platform. A gasket 52 between the conical member 43 and the drive shaft provides an upper fluid tight seal for the pressure chamber 47.

A source of pressure fluid (not shown) is connected to a central bore 51 in the drive shaft by means of connection for supplying a pressure fluid to chamber 47 when it is desired to move the centering device into its operative condition. When fluid is supplied to the pressure chamber under pressure, the conical member 43 is axially moved against the bias of spring 44 and into engagement with complementary conical hub member 45 so as to prevent angular movement of the two members in respect of each other about joint 13' and thus to hold the basket 10 and drive shaft 12" coaxial.

Furthermore, a damping device is shown interposed between the drive shaft 12" and the basket 10 for restraining the pivoting movements of the basket in respect of the shaft. The illustrated damping device comprises transverse element constituted by an annular disk 53 coaxial with the shaft and mounted thereon for gliding and angular movement in respect of the axis of shaft 12", the disk being supported by a swivel joint 54 freely glidable on the shaft. Clamping means constituted in the illustrated embodiment by a pair of

clamps

56, 56 is fixed on the hub 45 of the basket. The clampscarry friction members 57 wherebetween the disk 53 is engaged. The clamping force is provided by springs 55 whose bias may be adjusted by nuts 55a threadedly mounted on bolts 55b which connect the clamps to the basket hub 45. Obviously, the arrangement could be reversed, i.e., the clamps could be fixed to the drive shaft and the disk could be mounted on the basket.

The centering and damping devices are positioned within the conical hub member 45 which is closed by a fluid tight flexible membrane 58 at the bottom of the conical hub member and a fluid tight annular gasket 59 positioned between the

clamps

56, 56 along the periphery thereof.

The damping device opposes movements causing a change of direction of the axis of the drive shaft-basket assembly or limits the amplitude of such movements to an admissible value. When such a change of direction takes place, the drive shaft turns slowly about the vertical axis passing through the center of the joint suspending the shaft for pendular movement while the basket turns about its axis of inertia. This results in an angular movement of the basket in respect of the shaft about joint 13, which causes displacement of disk 53 between

clamps

56, 56. The friction forces opposing the displacement of the disk are thus opposed to the movement of change of direction of the axis.

It may be noted that the centering and damping devices illustrated in FIG. 3 could also be used at the level of articulated suspension of the drive shaft to prevent or limit oscillations of the drive shaft in respect to the motor shaft to which the drive shaft is coupled by a universal joint or a flexible coupling, as shown, respectively, in FIGS. 1 and 2.

FIG. 4 illustrates another type of centering device used at the point of articulated suspension of the drive shaft. This device, too, is normally inoperative to permit pendular movements of the drive shaft in respect of the frame support in the inoperative position thereof, and maintaining the drive shaft axis fixed in the operative condition.

A bearing support 69 mounted on the frame support (not shown in this figure) holds a dished support 70 forming a ball-and-socket joint with complementary bearing race 63 in a manner similar to the pendular suspension of the drive shaft shown in FIG. 1. The dished support 70 has a central bore through which the bearing race 63 extends, and roller bearings support the drive shaft 12" in the bearing race for swivel motion of the shaft in respect of the bearing support 69. A flexible coupling 22 connects the drive shaft to motor shaft 26 The centering device comprises a flanged member 60 fixed to the pendularly movable bearing race 63 wherein the drive shaft is rotatably joumaled, and a cooperating ram member 61 radially displaceable into and out of engagement with the flanged member 60 by a pressure fluid operated piston 62 moving each ram ally inwardly into engagement with the flanged member to immobilize the bearing race 63 and thus the drive shaft against oscillatory motion about the joint 63, 70.

An elastic return means for the drive shaft is provided by springs 66 mounted in bearing support 69 and exerting a resilient radial force upon the drive shaft in opposition to the pendular movement of the shaft when the centering device is in the inoperative condition shown, i.e., when the rams 61 are disengaged from flanged member 60. The bias of springs 66 may be adjusted by knob 68 threadedly mounted in the bearing support 69 for axial movement in relation to the spring.

If the centering devices for keeping the axis of the drive shaft fixed in respect of the frame support and for maintaining the position of basket and drive shaft fixed are operated, dried matter may be removed from the inside of the basket by a fixedly mounted scraper without damaging the basket. Since this operation is effected at low rotary speed, it makes no difference that the entire assembly is rigid in this condition of the centering devices.

Since the critical rotary speed of the drive shaftbasket assembly is relatively high when the two centering devices are in the blocking position and low when they are inoperative so as to permit articulation, the discharge speed may be chosen between these two critical speeds, which avoids having to break through a critical speed at the moment when it is desired to block or unblock the articulations.

Obviously, the joint pivotally mounting the rotor on the drive shaft may be a universal joint, such as a Cardan joint, or any other type of thrust joint capable of absorbing axial forces. Such a joint may replace the ball-and-socket joint and the flexible coupling connecting the shaft to the rotor. In this case, as illustrated by way of example in the shaft suspension of FIG. 4, which obviously may be applied to the pivotal mounting of the rotor on the shaft end, the elastic return means may be constituted by springs exerting a pressure on the shaft or the rotor, respectively, as well as elastic rings or annularly disposed elastic blocks.

While the apparatus has been described and illustrated in connection with centrifugal driers such as used particularly in sugar refineries for separating sugar crystals from their mother liquor, it will be obvious to those skilled in the art that the present invention will be useful in any machine where a rotor is suspended at the lower end of a vertical drive shaft, such as certain impellers, for instance ventilators or pumps.

We claim:

1. In an apparatus comprising a frame support; a vertically extending rotary drive shaft having a lower end, means for suspending the drive shaft on the frame support for pendular movement in respect thereto; a rotor; and a joint pivotally mounting the rotor on the lower end of the drive shaft, said joint including a flexible coupling connecting the rotor to the shaft whereby the rotor may be driven by the shaft upon rotation thereof while being permitted to pivot in respect of the shaft: a damping device interposed between the drive shaft and the rotor for damping the pivoting movements of the rotor in respect of the shaft.

2. The apparatus of claim 1, wherein the joint is a ball-and-socket joint.

3. The apparatus of claim 1, wherein the joint is a universal joint.

4. The apparatus of claim 7, wherein the elastic return means comprises two coupling plates respectively fixed to the rotor and the shaft, and an elastically deformable device mounted between the plates whereby one of the plates may be displaced in respect of the other one of the plates.

5. The apparatus of claim 4, wherein the elastically deformable device is an annular member of deformable material interposed between the plates.

6. The apparatus of claim 4, wherein the elastically deformable device consists of spring means interposed between the plates.

7. The apparatus of claim 1, further comprising an elastic return means interposed between the rotor and the shaft and tending to move the rotor opposite to the pivoting movements thereof.

8. The apparatus of claim 1, wherein the damping device comprises a transverse element mounted on the drive shaft for gliding and angular movement in respect of the axis of the shaft, and clamping means fixed on the rotor and clampingly engaging the transverse element.

9. The apparatus of claim 8, wherein the transverse element is an annular disk coaxial with the shaft, and the clamping means consists of a pair of clamps between which the disk is engaged.

10. The apparatus of claim 1, further comprising a normally inoperative centering device permitting the pivotal movements of the rotor in respect of the drive shaft in the inoperative condition thereof, and maintaining the rotor and shaft coaxial in the operative condition.

l l. The apparatus of claim 10, wherein the centering device comprises a pair of complementary and interengageable conical members, one of the conical members being glidingly mounted on the drive shaft for movement in an axial direction and the other one of the conical members being fixed to the rotor, and means for moving the one conical member from the inoperative condition of the device wherein the members are out of engagement into the operative condition wherein the one conical member engages the other conical member.

12. The apparatus of claim 1, further comprising a normally inoperative centering device permitting the pendular movements of the drive shaft in respect to the frame support in the inoperative condition thereof, and maintaining the drive shaft axis fixed in the operative condition.

Claims

2. The apparatus of claim 1, wherein the joint is a ball-and-socket joint.

3. The apparatus of claim 1, wherein the joint is a universal joint.

11. The apparatus of claim 10, wherein the centering device comprises a pair of complementary and interengageable conical members, one of the conical members being glidingly mounted on the drive shaft for movement in an axial direction and the other one of the conical members being fixed to the rotor, and means for moving the one conical member from the inoperative condition of the device wherein the members are out of engagement into the operative condition wherein the one conical member engages the other conical member.