US3706237A

US3706237A - Device for driving a rotary element capable of deformation and of displacement parallel to its theoretical axis of rotation

Info

Publication number: US3706237A
Application number: US184557A
Authority: US
Inventors: Gerard Pere
Original assignee: Creusot Loire SA
Current assignee: Creusot Loire SA
Priority date: 1971-01-08
Filing date: 1971-09-28
Publication date: 1972-12-19
Anticipated expiration: 1989-12-19
Also published as: ES398422A1; SE376068B; DK137285B; FR2120565A5; NO134188C; IT945828B; NO134188B; BE776091A; AT318998B; DK137285C; CH542417A; GB1375214A; JPS5110314B1; DE2163326A1; DE2163326B2; DE2163326C3; NL7117564A

Abstract

A device for driving a rotary element, more particularly a rotary kiln, capable of deformation and displacement along its axis and comprising a toothed rim driven by a pinion mounted in a housing articulated on a fulcrum and bearing on two cylindrical tracks coaxial with the rim by way of at least one pair of rollers, characterized in that the housing is connected to a fixed block by a member capable of producing displacement of the fulcrum in a direction parallel to the axis of rotation of the kiln, freely following displacements of the kiln.

Description

United States Patent Pei-e 1451 Dec. 19, 1972 541 DEVICE FOR DRIVING A ROTARY 3,299,729 l/l967 Durand ..74/41o x EL M NT CAPABLE O 3.490306 1/1970 Hansgen et al. ..74/41o 3,534,624 10/1970 Durinck ..74/410 DEFORMATION AND OF 3,572,150 3/1971 Durand ..74/410 DISPLACEMENT PARALLEL TO ITS THEORETICAL AXIS 0F ROTATION Inventor: Gerard Pere, Le Breuil, France Assignee: Creusot-Loire, Paris, France Filed: Sept. 28, 1971 Appl. No.: 184,557

Foreign Application Priority Data Field of Search ..74/4 1 0 References Cited UNITED STATES PATENTS v 2/1965 Durand ..74/4l0 X Primary Examiner-Leonard H Gerin Attorney-William B. Kerkam, Jr.

[57] ABSTRACT A device for driving a rotary element, more particularly a rotary kiln, capable of deformation and displacement along its axis and comprising atoothed rim driven by a pinion mounted in a housing articulated on a fulcrum and bearing on two cylindrical tracks coaxial with the rim by way of at least one pair of rollers, characterized in that the housing is connected to a fixed block by a member capable of producing displacement of the fulcrum in a direction parallel to the axis of rotation of the kiln, freely following displacements of the kiln.

7 Claims, 9 Drawing Figures PATENT'ED DEC 19 I972 SHEET 2 OF 3 DEVICE FOR DRIVING A ROTARY ELEMENT CAPABLE OF DEFORMATION AND OF DISPLACEMENT PARALLEL TO ITS THEORETICAL AXIS F ROTATION The invention relates to a device for driving a rotary element capable of deformation and of displacement parallel to its theoretical axis of rotation.

Numerous driving devices are known for rotary elements liable to deformation, such as rotary kilns, grinders or steel converters. A number of proposed devices are intended to drive these rotary elements satisfactorily in spite of the deformation which they undergo due to expansion or due to changes in the stresses applied to them while they are in use. The driving devices usually comprise a toothed rim fixed to and coaxial with the rotary element and means for rotating the rim by way of a driving member. The driving member must be able to follow the deformations of the rim. The invention relates more specifically to driving devices in which the rim driving member comprises a housing providedwith at least two rollers each of which bears on one of two cylindrical tracks coaxial with the rim the rim, and at least one pinion driven by the rim rotat- Y ing means, mounted on the housing, having its axis parallel to that of the rim and meshing with the rim. The rim driving pinion is therefore connected to the rim and can remain in contact with the teeth whatever the deformation to which the rim is subjected. Since the pinion must, of course, be held if it is to transmit rotary motion to the rim, the device comprises a member for connecting the housing to a fixed component, this connecting member being pivoted on a fulcrum for the housing. Contact between the pinion and the rim can be ensured either by the weight of the driving member itself, if the latter is placed above the axis of the rim, or by a resilient member which is pivoted on the housing and which urges the pinion onto the rim by bearing on afixed component.

In order to leave the driving member as a whole some freedom of movement, so that it can follow the deformation of the rim while remaining engaged, the connecting member is usually a draw-bar whose ends are connected by universal joints to the housing fulcrum and to a fixed component. This form of coupling is generally fairly satisfactory. Apart from the deformation of the rim, however, it may happen that the rotary element is displaced along its axis. This occurs, for example, with rotary kilns in which expansion may cause appreciable axial displacement of the rim due to the considerable length of the kiln, and to which, moreover, a reciprocating movement along their axis is usually systematically imparted to prevent the supportv ing rollers from always bearing on the same parts of the running surfaces.

When the housing of the driving member is retained by a draw-bar pivoted at both ends, this bar turns on its pivot on the fixed component, following the longitudinal displacement of the rim, and the housing fulcrum therefore describes a circular are centered onthe fixed pivot. The bearing reaction, which is directed along the straight line joining the points at which the draw-bar is pivoted on the fixed component and on the housing, does not, therefore, remain perpendicular to the toothing. As a result the load on the toothing is distributed asymmetrically, which restricts the performance of the toothing and also creates appreciable axial thrust which must be absorbed by an abutment on the rim.

An object of the invention is to provide a driving device which overcomes these disadvantages.

According to the invention, the connecting member is capable of causing displacement of the housing fulcrum in a direction parallel to the theoretical axis of rotation of the rotary element, freely following axial displacement of the rotary element.

According to the supplementary feature of the invention, the bearing reaction remains substantially in the central plane of the pinion during displacement of the rotary element.

A first embodiment of the invention, which will be described below, is characterized in that the'connectingmember is an articulated system formed of a lever which is pivoted about the housing fulcrum and on whose ends are pivoted two' rods of equal lengthsextending on each side of the lever in a plane parallel to the pinion axis, the other end of each rod pivoting about a fixed axis perpendicular to this plane.

A second embodiment of the invention described below is characterized in that the connecting member is at least one strut pivoted on the housing fulcrum and bearing-on a fixed plane perpendicular to the resultant of the stresses applied to the housing during rotation of the driven rotary element at its normal running speed, along a cylindrical surface whose axis passes through the fulcrum, is in the central plane of the pinion and is parallel to the said fixed plane.

The invention will now be described in detail with reference to particular embodiments, given by way of example and illustrated in the accompanying drawings, in which:

. FIG. 1 represents a cross-section through part of the driving rim for a rotary element and the drivin member;

FIG. 2 is an elevation in the direction II-II in FIG. 1, showing the driving member illustrated in FIG. 1;

FIG. 3 is an elevation 'of the connecting member on a larger scale, as seen in the direction IIIIII in FIG. 1;

FIG. 4 is a section on a line IV-IV in FIG. 3;

FIG. 5 is a section on a line V-V in FIG. 3;

FIG. 6 is a diagrammatic perspective view of the connecting member;

FIG. 7 is a cross-section through a second embodiment of the invention;

FIG. 8 is an elevation of the connecting member in the second embodiment on a larger scale; and

FIG. 9 is a section on a line IX-IX in FIG. 8.

In the embodiment shown in FIGS. 1 to 6, the rotary element 1 is a cylindrical drum surrounded by a rim 2, provided on its circumference with toothing 3 meshing with a pinion 4 whose axis is parallel to the axis of the rim and which is mounted on a housing 5. This housing consists chiefly of two side plates 51, 52 enclosing the pinion and connected by spacers so that the housing is rigid enough to hold the pinion pivot.

The rim 2 is provided, on each side of its plane 0 symmetry, with two cylindrical tracks 21, 22 coaxial with the rim. A roller 53 pivotably mounted on the housing 5 runs along each of these tracks. The housing 5 is articulated at a fulcrum 54, normally placed in the central plane of the pinion, on a system of articulated rods 6 (FIG. 2) consisting of a lever 60 which is pivoted at its center on a ball centered on the fulcrum 54 and on whose ends two

rods

61, 62 are pivoted, the other ends of these

rods

61, 62 turning respectively on

pivots

63, 64 mounted on a fixed base 65. The lengths of the

rods

61, 62 are equal. The

pivots

63, 64 are parallel to one another and perpendicular to a plane passing through the axis of the pinion 4. The articulated system 6 therefore remains within this plane when it is deformed.

The articulated system 6 is shown diagrammatically in FIG. 6. It is well known that if in a mechanical system of this kind, known as a Watt system, the ratio between the lengths of the central lever 60 and of the

rods

61, 62 is suitably chosen, the mid-point 54 of the lever will be displaced along a substantially straight line when the system is deformed, and the

rods

61, 62 will turn through a substantially equal angle. As a result, a force exerted on the mid-point 54 at right-angles to the direction of the straight line A along which this point shifts will produce only a very small reaction in the direction of A due to the difference of inclination between the

rods

61 and 62, this difference being practically zero, of course, if certain limits are observed.

In the case of a rotary element such as arotary kiln, the amplitude of the admissible longitudinal displacements is known. It is easy to calculate the lengths of the rods and of the central lever and to arrange the system so that the bearing reaction exerted by the housing on its fulcrum 54 is perpendicular to the direction A along which the mid-point 54 may shift.

In general the pinion 4 is applied to the teeth 3 by a resilient member 7 (FIG. 1) compressed between a fixed bearing block 71 and a pivot 72 on the housing 5. From the force applying the housing to the rim, the position of the rollers 53 and the orientation of the teeth reaction for a normal rotary-element driving torque, the average orientation of the resultant of the teeth in spite of axial displacement of the rotary element. It is therefore possible to transmit high torques'to the pinion at low speeds by way of a fixed motor-driven reducing unit 9.

Even higher torques can be transmitted to the rim by using, as described in French Pat. specification No. 1,465,384, two intermediate pinions meshing with the rim, loosely rotatable on the housing 5 at some distance from one another, and driven by a pinion which is axially connected to the housing, is between the two intermediate pinions and is held radially by its teeth. It is the latter pinion which will be driven by the coupling shown in FIG. 2. Obviously, the stresses applied to the entire device will be taken into account when calculating the position of the fulcrum 54 and the orientation of the plane of the articulated system 6. i

The housing 5, which bears on the tracks 21 and 22.

. by way of rollers 53 and is connected to the lever 60 by forces applied to the housing can easily be deduced.

The plane of the articulated system 6 is therefore directed according to this resultant.

When the rotary element is displaced along its theoretical axis of rotation within the admissible limits, therefore, the bearing reaction is displaced parallel to itself and remains perpendicular to the axis of displacement. As a result there is no appreciable axial component and therefore no housing tilting couple. The pressure continues to be distributed evenly along the toothing, and the gearing operates under excellent conditions.

Advantageously, as shown in FIG. 2, the housing connecting member 6 just describedmay be combined with a coupling comprising a plurality of articulated systems similar to that forming the connecting member. A coupling of this type is described in our US. Pat. application No. 7,100,193 filed on 6.1.71. It enables a driving torque to be transmitted to the pinion 4 while adsorbing longitudinal displacement of the pinion relative to the driving shaft, without causing any appreciable reaction to be exerted on the pinion. Clearly, the combination of the two devices and the addition of a counterweight 8 to balance the stresses due to the weight of the coupling and of the transmission shaft ensure an excellent distribution of the pressure over the a ball joint, canstill, of course, shift slightly in any direction and so follow any deformation of the toothed rim or of the rotary element, as, in the assemblies proposed before.

In the embodiment shown in FIG. 7, the housing connecting member is a strut l0 articulated on a pivot 11 mounted on a fork joint 55 fixed to the housing. The pivot 11 is preferably provided with a ball joint whose center forms the housing fulcrum 54, and is normally placed in the central plane of the pinion. I

The strut 10 is shown in detail in FIGS. 8 and 9.

This strut 10 is supported on a fixed plane 12 perpendicular to the resultant of the stresses applied to the housing during rotation of the rotary element when driven at its normal running speed, by way of a cylindrical surface 13 whose axis passes through the fulcrum 54 and is parallel to the plane 12 and to the central plane of the pinion, the fulcrum 54 being in the said central plane. This arrangement applies if.the housing 5 has four rollers 53 arranged in pairs on each side of the pinion axis. Under these conditions the resilient bearing means 7 can be sited so that the strut need support only the teeth reaction and is therefore placed parallel to the teeth reaction produced in the case of a normal rotary-element driving torque.

The end of the strut is held in a fork joint 14 attached to the fixed support. The two side plates of this fork joint contain oblong orifices 141 to receive a pivot 101 which passes through the strut. This pivot enables the strut to withstand unexpected traction, but does not impede rotation of the strut on the bearing surface 13. Lastly, keys 15 which slide in recesses in the strut and in the bearing member 12 prevent the strut from sliding and oblige the strut to pivot on its bearing surface 13.

With an arrangement of this kind, of course, the bearing reaction perpendicular to the plane 12 is displaced parallel to this direction in the event of axial displacement of the rotary element, since the strut pivoting on its cylindrical bearing surface follows the displacement of the rotary element freely without producing a reaction against the housing 5.

In this case, also, the provision of the fulcrum on a ball joint enables the housing 5 bearing on the rollers 53 to follow any deformation of the rim while keeping the pinion engaged.

In the embodiment illustrated, the housing 5 was provided with four bearing rollers and one articulated strut. Alternatively, of course, as in the embodiment shown in FIG. 1, only two bearing rollers might be used. In this case two struts would be provided, in order to absorb the resultant of the stresses applied to the housing.

The sole purpose of the resilient member 7 is to apply the pinion to the rim, and its length can vary as it follows the displacements of the rotary element. If it is pivoted on the bearing block 71, therefore, it can transmit only slight axial reactions. However, to eliminate even these reactions, the bearing plane 71 is preferably parallel to the theoretical axis of rotation of the rotary element, and the resilient member 7 preferably bears on this plane either by way of an articulated system similar to the system 6 shown in FIG. 1 or, like the strut 10, along a cylindrical surface whose axis is parallel to this plane and perpendicular to the axis of rotation of the rotary element. The support would be identical to that shown in FIGS. 8 and 9, and the resilient member would therefore follow displacements of the rotary element freely, transmitting to the pinion a pressure which is always at right-angles to the pinion axis.

it has been stated that the plane of the articulated system 6 or of the strut 10 is parallel to the resultant of the stresses applied to the housing and also passes through the pinion axis. It may be useful to further separate the fulcrum from the tangent plane common to the pitch circles of the sets of teeth, so that the plane of the strut forms with the tangent plane an angle greater than the pressure angle. If so, the stress applying the pinion will increase in proportion to the torque transmitted, removing any risk of separation. If the position of the housing fulcrum is chosen correctly, the resilient member will therefore need to absorb, in addition to the weight of the driving member itself, only the force required to apply the pinion to the rim when stationary.

Obviously, the invention is not restricted to the details of the two embodiments described. Other connecting members, such as slides, might be suitable, provided that they produce displacement of the housing fulcrum in a direction parallel to the theoretical axis of rotation, while freely following displacement of the r0- tary element so that the bearing reaction remains substantially in the central plane of the pinion, without the connecting member being able to transmit to the housing an axial component due to the displacement of the rotary element.

In particular, the two embodiments described make it possible to absorb axial displacement of the kiln of the order of 60 mm on each side of its central position.

A device of this kind can transmit high torques to the rim and cab therefore use a fixed reducing unit, particularly if the device just described is combined with a coupling of the type described in the above-mentioned prior Application. Clearly, however, the same result would be obtained by combining the device described in the present Application with any other coupling capable of transmitting the torque and of absorbing axial displacement without producing a reaction on the floating pinion.

Lastly, it should be noted that the articulated system 6 used in the embodiment shown in FIG. 1 can absorb both thrust and traction without any axial reaction. If

desired, the housing fulcrum could therefore be placed to either side of the axis of the driving pinion.

I claim:

which bears on one of two cylindrical tracks coaxial with the rim and situated on each side of the plane of symmetry of the rim, at least one pinion driven by the rim rotating means, mounted on a housing and having its axis parallel to that of the rim and meshing with the rim, and a member for connecting the housing to a fixed component, this connecting member being pivoted on a fulcrum for the housing, characterized in that the connecting member is capable of causing displacement of the housing fulcrum in a direction parallel to the theoretical axis of rotation of the rotary element, freely following axial displacement of the rotary element.

2. A driving device as claimed in claim-1, characterized in that the bearing reaction remains substantially in the central plane of the pinionduring displacement of the rotary element.

3. A driving device as claimed in claim 1, characterized in that the connecting member is an articulated system formed of a lever which is pivoted about the housing fulcrum and on whose ends are pivoted two rods of equal lengths extending on each side of the lever in a plane parallel to the pinion axis, the other end of each rod pivoting about a fixed axis perpendicular to this plane.

4. A driving device as claimed in claim 1, characterized in that the plane of the articulated connecting system for the housing is directed according tothe resultant of the stresses applied to the housing during rotation of the driven rotary element at its normal running speed.

5. A driving device as claimed in claim 1, characterized in that the connecting member is at least one strut pivoted on the housing fulcrum and bearing on a fixed plane perpendicular to the resultant of the stresses applied to the housing during rotation of the driven rotary element at its normal running speed, along part of a cylindrical surface whose axis passes through the fulcrum, is in the central plane of the pinion and is parallel to the said fixed plane.

6. A driving device as claimed in claim 1, characterized in that the rim rotating means comprises a combined, fixed driving and reducing unit driving the pinion by way of an extension provided with a coupling capable of absorbing axial displacement of the pinion relative to the reducing unit without transmitting an axial reaction to the pinion, the housing being provided with means for balancing the weight of the extension and of the coupling.

7. A driving device as claimed in claim 1, characterized in that the connecting member extends in a plane passing through the pinion axis and forming an angle greater than the pressure angle with the tangent plane common to the pitch circles of the sets of teeth.

Claims

1. A device for driving a rotary element capable of deformation and of displacement parallel to its theoretical axis of rotation, comprising a toothed rim fixed to and coaxial with the rotary element and means for rotating the rim by way of a driving member comprising a hub provided with at least two rollers, each of which bears on one of two cylindrical tracks coaxial with the rim and situated on each side of the plane of symmetry of the rim, at least one pinion driven by the rim rotating means, mounted on a housing and having its axis parallel to that of the rim and meshing with the rim, and a member for connecting the housing to a fixed component, this connecting member being pivoted on a fulcrum for the housing, characterized in that the connecting member is capable of causing displacement of the housing fulcrum in a direction parallel to the theoretical axis of rotation of the rotary element, freely following axial displacement of the rotary element.

2. A driving device as claimed in claim 1, characterized in that the bearing reaction remains substantially in the central plane of the pinion during displacement of the rotary element.

4. A driving device as claimed in claim 1, characterized in that the plane of the articulated connecting system for the housing is directed according to the resultant of the stresses applied to the housing during rotation of the driven rotary element at its normal running speed.