CA2127131C

CA2127131C - Arrangement for the rotary actuation of a machine and plant part with worm gear

Info

Publication number: CA2127131C
Application number: CA002127131A
Authority: CA
Inventors: Klaus Stoll; Erich Russ
Original assignee: IMO Momentenlager GmbH
Current assignee: IMO Momentenlager GmbH
Priority date: 1993-06-19
Filing date: 1994-06-17
Publication date: 2004-11-30
Anticipated expiration: 2014-06-17
Also published as: EP0631068A1; CN1101109A; DE9311316U1; KR0144542B1; CA2127131A1; ES2086978T3; DE59400180D1; JPH07139594A; AU678003B2; AU6474294A; ATE136347T1; EP0631068B1; KR950001146A; CN1048541C; JP2914476B2; DK0631068T3

Abstract

A worm and worm wheel arrangement for the rotary drive of a machine or plant party such as a crane.
includes a housing in which the worm and the mating worm wheel are mounted. The connection to the machine is provided on one side of the worm wheel. Inner bearing rings are provided on the worm wheels one on each side thereof and a first outer bearing ring is provided on a base portion of the housings there being bearing elements between the first outer ring and the adjacent inner ring. A cover for the housing includes thereon a second outer bearing ring and bearing elements are provided between the second outer ring and the adjacent inner ring. The cover serves to bearingly retain the worm wheel within the housing.

Description

Arrangement for the rotary actuation of a machine and plant part with worm gear The invention relates to an arrangement for the rotary actuation of a machine or plant part, for example of a crane, on a chassis or foundation, using a worm gear, the housing of which is secured on the chassis or foundation.
On known drives for mobile cranes, the pivoting movements are brought about, for example, by means of two hydraulic cylinders, which are formed as gear racks and are disposed to the left and right of a king trunnion mounting. The rotatory forces are transmitted onto a largely dimensioned pinion by means of the gear rack. Through this arrangement of the hydraulic cylinder drives, the gear used maintains considerable elongation in order to transmit high tilting moments.
A gear arrangement is known (DE-OS 34 46 438) wherein the worm wheel is mounted through only one cross roller bearing.
Through the single-shear bearing arrangement a tilting moment arises through the drive (worm wheel, worm). This has an adverse effect, because through this, supporting capability of the single-shear bearing is lost and such high external forces cannot be transmitted. Furthermore, a higher tilting of the worm wheel arises through the single-shear bearing arrangement, which has a very adverse effect on the engagement relationships of the worm gearing. The single-shear bearing connects through a screw connection of the outer ring with the housing and of the inner ring with the worm wheel. This is associated with extra expenditure of production and assembly.
Furthermore, arrangements with worm gears of approximately the initially named kind are known (US-A-4 616 528, US-A-3 710 640, EP-A-O 031 873, DE-A-33 21 854), on which the worm wheel in the gear housing is incorporated twice or two-shear. Two-shear bearing arrangement means that two separate bearings for the worm wheel, for example rolling bearings, are disposed coaxially to one another. In_the arrangements from the named sources, the worm gears are used without exception as a gear stage for valve applications, multiple drives particularly with d.c. motors or spindle lifting gears and spindle sliding gears. Common to these embodiments is that no particular arrangements are made against the influences of extraordinary tilting moments onto the shaft or axis of the worm wheel. The housings, as far as can be seen, are without exception one-pieced and on the basis of their structure, cannot contribute to guaranteeing or to at all increasing the solidity and stability of the axis or shaft of the worm wheel, which is used for example for output.
The object of the invention is to create a worm gear arrangement for rotary actuation, which on the one hand has a compact, space saving construction and on the other hand has the capability to take up and transmit extraordinarily high external forces (axial and radial forces) and moments, above all tilting moments.
The gear housing then, is divided into an upper and lower part, one of the two parts being interspersed by the connection attachment of the worm wheel to the machine or plant- part to be rotated. In that the outer rings of the two rolling bearings are each secured at an upper and lower part of the housing and the corresponding inner rings are secured at the worm wheel, and following that, the upper part and lower part axe tightly screwed together to form the entire housing, a compact, space saving and solid unit results, in which the gear and bearing arrangement are constructionally integrated into one another. In ~1~'l~.~l.
particular, the rolling bearings are braced and additionally stabilized by this. In this way the part to be rotated with extraordinary weight can be assembled on the worm wheel, whereby not only high axial and radial forces, but also high tilting moments can be taken up in an operationally safe way.
The gear arrangement according to the invention is suitable above all for directly driving machines and plant parts. It can replace the known rotatory connections and pinion with intermediate gearing, with less constructional expenditure and increased reliability. In that the two-shear bearing arrangement of the worm wheel cooperates, according to the invention, with the housing parts which are screwed together, a worm wheel with simple construction and large coat saving can be taken up in the gearing housing, which is also robust relative to tilting moments.
Due to the closed housing, the drive arrangement according to the invention is largely screened against parasitic induction from the surroundings, which increases the ease of maintenance. No such high demands of constructional exactness need be placed on the connection construction with the connecting attachment, since the drive arrangement according to the invention has a high intrinsic rigidity to start with. Thia results, among other things, from the measure according to the invention that, on the one hand the worm wheel and on the other hand the upper and lower part (base or cover part) of the gear housing are each used as carrier elements for the hardened raceway shells (inner and outer rings) of the two-shear bearing arrangement.
Furthermore, the two housing parts are rigidly connected with one another or fixed to each other. The bearings of the worm wheel can be four-point bearings (ball), as well as roller bearings. The bearing forces are transmitted by means of further securing screws at outer flanges of the housing or the like, into the surrounding construction. Due '~ ~ II~~IIJ~.

to the measures according to the invention, the housing and the worm wheel are in the position to take up the high external forces stemming from the heavy machine and plant parts, said high external forces being transmitted by means of the bearings. The upper part or cover part of the housing can for example take over the function of taking up the external tensile forces. Furthermore, the housing can hold the bearing free of backlash or hold the initial tension.
According to a particular embodiment, the housing parts lie together via sealing means in order to be sealed against the environment.
The basic principle according to the invention of spatially extending, as it were, the bearings of the highly loaded worm wheel in the applications contemplated, corresponds to a further development of the invention according to which the worm wheel is mounted rotationally by means of two separate inclined rolling bearings, on which the rolling elements are each encompassed, by the inlays or by the inner and outer ring, with a peripheral section between 60° and 120°, preferably approximately 90°. This excludes the way known per se (see above) of arranging the worm wheel with a single cross rolling bearing. Radial, axial loads and tilting moments can be advantageously taken up by means of the two angular ball bearings.
To achieve a constructively simple coupling of the part to be rotated to the gear arrangement it is suggested, according to another further development of the invention, that at least one end face or other non-geared side wall of the worm wheel is specifically formed to connect with the part to be rotated, be it through a ring of bores to be screwed, or through hook-shaped locking elements for. example or latching devices. A one-piece connection between worm ~1~'~1~1 wheel anal the part to be rotated is also conceivable within the framework of the invention.
The manufacturing costs are lowered when, according to another further development of the invention, the inlays or inner and outer ring of the rolling bearings are radially slotted throughout. The possibility is then created of not only manufacturing the inlays economically from a single run, but of also being able to spread the inlays out quickly during the incorporation or the assembly.
By using rolling bearings, the outer ring is expediently fixed at the inner wall of the gear housing and the inner ring at the worm wheel to be rotated. The rolling bearings are connected by the gear cover to form one unit.
So that as high a torque as possible can be transmitted, two or more worms according to another development of the invention are disposed which act upon the (common) worm wheel.
With extreme loading it can also be expedient within the framework of the invention to embody rolling bearings with several rolling ring elements which roll off tracks and which are angled to each other. Here for example, a rolling ring element can be provided exclusively for transmitting radial forces and each further rolling ring element for transmitting axial forces in both directions of moments.
The first rolling element set would roll off cylindrical running tracks whereas the two other rolling ring elements roll off on flat surfaces perpendicular thereto. Such bearing modules are known per se as double axial radial bearings.
In known worm drives, particularly when they are not used purely as transmitting drives but in the sense of the type according to the invention for directly driving machines and ~I~ f ~.al.

plant parts, (DE-OS 34 46 438), the following problem can easily arise: The rotating worm wheel must sometime be braked in the shortest possible time. since, as a rule, a lot of mass moves with the rotating worm wheel in the named applications, kinetic energy is to be converted to a large extend. As a result of this, it can happen when braking quickly, that the worm wheel gearing or the worm thread engaging it, breaks.
Consequently, the further problem within the framework of the invention is raised, of intercepting dynamic forces arising during the running and in particular the braking of the worm wheels which are coupled with a machine part and to compensate such that a destruction of the gear engagement between worm and worm wheel is prevented. To achieve this, in a worm gear arrangement with the initially named features according to the invention, it is suggested that the worm is not only rotationally mounted, but is also mounted displaceably in its longitudinal direction against spring force (linear). In other words, one or several spring elements are disposed within the gear housing such that they stand in the way of the linear displacement of the worm with their spring force. This can be expediently achieved in that the spring element or elements on the one hand are supported or engaged against the housing wall and on the other hand at the worm. With this embodiment according to the invention, mass forces of the rotating parts can be compensated without the gearing being damaged due to overloading. A shock-type braking is avoided.
Spring devices are advantageously combined in the set after one or both ends of the worm thread, for example one or several screws or adjacent Belleville spring washers, which each engage between a thread end side and the worm shaft end while supported against the housing wall.

With the spring compliance according to the invention, the worm is allowed a certain stroke within the housing or framework by means of which braking forces and deceleration loading can be balanced out or compensated.
The worm in each case is advantageously mounted on both sides at its ends with a radial and axial bearing, because through this the external mass forces or impacts can be softened and pretensioned Belleville spring washers can be disposed between the axial bearings and the worm.
With the aim of strengthening the robustness against tilting moments, an expedient embodiment exists in that the cover and base part of the housing are placed on top of each other in the direction of the worm wheel axis or parallel thereto.
The adjacent support surfaces of the two housing parts increase the solidness and then prevent the tilting together of said housing parts, a stable support being also guaranteed for the outer rings of the two-shear worm wheel bearing arrangement. Advantageously the common support surfaces of the housing parts are dimensioned such that they can be interspersed by fixing means, particularly screw means. The tilting is further reacted,against when the fixing or screw means extend parallel to the worm wheel axis, the common support surfaces of the housing parts being pressed together with maximum force. By this means the stability of the bearing arrangement is optimized.
Within the framework of the invention the connecting attachment of the worm wheel intersperses the cover or base part or one of the two housing parts axially or parallel to the axis. By this means the connection extension can particularly easily be used for receiving and for carrying the machine or plant part to be rotated.
The worm gear actuation drive arrangement according to the invention can be used particularly in mobile, construction, ~~~ ~~u~

harbour and industrial cranes, excavators, lifting platforms, deep shovel dredgers, concrete mixers, fork lifting ancillary equipment, revolving welding tables and concrete pumps, for forming the necessary rotatory connection in each case. Further areas of application for the drive arrangement according to the invention are swinging devices for grabs, track pinch bars, working load turning machines, ancillary manipulators, swinging stacker equipment, car park systems, swinging lifting platforms, motor vehicle winches and wall winches, body bolsters for heavy road vehicles, steering drive units for heavy goods vehicles, machines for packing and filling, labelling, sorting, mixing and stirring works, thickening plants and research plants for discharge water and mud treatment, construction machines, drag bearings, dredger-loaders, universal dredgers, robots, feeding machines, rotary indexing tables and reversible clamping devices.
Further details, features and advantages on the basis of the invention result from the sub claims as well as the following description of a preferred embodiment of the invention with reference to the drawings, in which:
Fig: 1 is a perspective illustration of a drive arrangement with worm gear, Fig: 2 is a plan view according to the direction II in Figure 1, Fig: 3 is a section according to the line III - III in Figure 2 Fig: 4 is an enlarged illustration of the details IV in Figure 3 and Fig: 5 is the ball bearing used in the arrangement according to Figures 1 - 4 in axial plan view.

~~~~~~J~

According to Figure 1 the worm gear 1 for the actuation arrangement used according to the invention, comprises a gear housing 2, (Fig. 3) with a base part 2a, in which a worm 3 and a worm wheel 4 are mounted rotationally. The base part 2a has a support surface 20, interspersed by a row of inner thread bores 21 axially parallel to the worm wheel 4. At the straight front side of the base part 2a largely bent in the example, a projecting securing flange 22 is formed, over the securing holes 23 of which a fixing to a foundation or chassis (not shown) can be effected. The worm 3 which engages with the gearing 6 of the worm wheel 4 by means of its screw-shaped thread 5, is provided for coupling with a torque drive motor (not shown).
The worm wheel 4 has at its end side an axially parallel or cylindrically projecting connection attachment 7, in the end wall 8 of which a multitude of securing elements, e.g. screw bores 9 are formed in rows in the direction of the periphery or in rings. These are used to secure a machine or plant part to be rotated (not shown). Lying on the end side of the worm wheel-gearing 6, is the smaller inner ring 10 of an angular ball bearing (Figure 4) visible in Figure 1. By inserting a multitude of balls 11 (Figures 3 and 4) into this inner ring 10 and setting on of a (larger) outer ring 12, the complete angular ball bearing l0, 11, 12, is formed.
As can be seen from Figure 1 and above all from Figure 2, a atop shoulder 13 in each case at a distance from the two end faces of the worm thread 5 is raised and projects in an annular fashion around the worm shaft. Between each of these stop shoulders 13 and the worm end sections 14 mounted rotationally in the wall of the housing 6, one or several sets 15 of a multitude of individual Belleville spring washers 16 are disposed particularly such that they clamp.
The Belleville spring washers 16 or the corresponding sets 15 are slipped onto the worm 3 on both sides of the worm ~:I~'~131 thread 5 via their inner recesses until they abut the corresponding stop shoulder 13.
The Belleville spring washers 16 are annular platelets which, according to the partial cross-section illustration in Figure 2, increasing from their planes, deviate in their two dimensional annular areas by an inclined angle. Within a spring set 15 at least two such Belleville spring washers 16 are laid mirror-imaged to one another such that only their outer edges, which project the most from the said annular plane area, make contact. This deviation is elastically reversibly reduced during axial force, for example, due to transient deceleration or acceleration of the worm wheel 4. The possibility of linear stroke movements 17 for the worm 3 in the gear housing 2 results from this. By means of these stroke movements 17 of the worm 3, dynamic forces arising with abrupt acceleration or deceleration of the worm wheel 2, for example when braking or running, can be taken up on both sides by the spring sets 15, so that an abrupt braking of load is possible without destroying the gearing 6 and/or the thread 5.
According to Figure 3 an (upper) cover part 2b is to be set flatly onto the support surface 20 (Fig. 1) of the lower base part 2a to form the entire housing 2. Connection screws 24 which are screwed into the inner thread bores 21 of the base part 2a and engage the cover part 2b by means of flush through bores, are used to rigidly fix together part 2a and part 2b. The worm wheel 4 is mounted such that it is rotatable opposite the gear housing 2 through two ball bearing sets 10, 11, 12, which each lie on one of the two and sides 6a, 6b of the worm wheel gearing 6. With this, the smaller inner ring 10 is always fixed at the corresponding end side 6a or 6b of the worm wheel gearing 6 and the larger outer ring 11 at the inner wall of the housing 2. Therefore, in that the bearing arrangement of the worm wheel 4 is spatially extended by the division of the bearing arrangement, each into a separate ball bearing set Z0, 11, 12 for the end sides 6a, 6b at the worm wheel gearing, radial loads Frad, axial loads FaX and tilting moments M~ can be taken up to an extraordinary extent, the torque Md of the worm wheel 4 required for the part to be driven, remaining largely unimpaired around its centre axis 18.
This advantageous effect of the two-shear bearing arrangement is further conveyed by the use of angular ball bearings according to Figure 4. The inlays or inner and outer rings 10, 12, each surround the bearing balls 11 with only a peripheral section of approximately 90°. If these are disposed flush according to Figure 3, coaxially or parallel to the axis, to the centre axis 18, a tilting moment Mk can be taken up with greater operational certainty by two cooperating bearings 10, 11, 12 at each one end side 6a, 6b of the worm wheel.
In Figure 5 a complete angular ball bearing set 10, 11, 12 is shown in plan view. Here, radial slits 19 can be seen which intersperse each of the inlays or smaller and larger rings 10 or 12.

Claims

1. Arrangement for the rotary operation of a machine on a foundation, said arrangement comprising a worm gear having:
a housing connectable to said foundation;
a worm; and a worm wheel for meshing with said worm, said worm wheel being rotatably supported in said housing on opposite sides of gearing of said worm wheel by roller bearings, said worm wheel being set in rotation manually or by a drive motor;
characterized in that:
said housing has a base part and a top part fixable to said base part;
at least one end face of said worm wheel is provided with a connecting projection extending beyond said housing for attachment to said machine to be rotated;
an outer ring of each of said roller bearings is connected to said housing; and an inner ring associated with each outer ring of said roller bearings is connected to said worm wheel.

2. Arrangement according to claim 1, characterized in that the worm wheel is mounted by means of two angular rolling bearings including a plurality of rolling bodies, in which a peripheral section of between 60° and 120° of the rolling bodies is enclosed in each bearing by the inner and outer ring (10, 12).

3. Arrangement according to claim 2, characterized in that the peripheral section of the rolling bodies enclosed in each bearing is 90°.

4. Arrangement according to any one of the claims 1 to 3, characterized in that the inner and outer rings of the two angular rolling bearings are slit.

5. Arrangement according to any one of claims 1 to 4, characterized in that the inner ring of said roller bearings has a diameter which is smaller than the diameter of said outer ring.

6. Arrangement according to any one of claims 1 to 5, characterized in that the base part and top part of the housing each have a recess, into which the outer rings are inserted.

7. Arrangement according to any one of claims 1 to 6, characterized by two or more worms meshing with said worm wheel.

8. Arrangement according to any one of claims 1 to 7, characterized in that the inner and outer rings of the roller bearings are provided with rolling tracks which lie at a predetermined angle relative to one another.

9. Arrangement according to claim 7, characterized in that the rolling bearings take the form of known combined radial and thrust bearings.

10. Arrangement according to any one of claims 1 to 9, wherein the worm and the worm wheel meshed therewith are each rotatably supported in said housing, characterized in that the worm is additionally supported so as to be displaceable in a longitudinal direction counter to a spring force.

11. Arrangement according to claim 10, characterized in that the spring force opposing the displacement is realized by one or more spring elements, which are supported relative to the housing wall and act upon the worm.

12. Arrangement according to claim 10 or 11, characterized in that the spring force opposing the displacement is realized by one or more spring elements, which act upon the worm between an end face of its thread and its immediately adjacent, rotatably supported end portion, and are supported relative to a housing wall of said worm gear.

13. Arrangement according to claim 11 or 12, characterized in that said one or more spring elements take the form of helical or cup springs, which are penetrated by the worm and are combined to form jointly tensionable sets of springs.

14. Arrangement according to any one of claims 1 to 13, characterized in that the top and base parts of the housing are placed one on top of the other and are screwed to one another in a selected one of a direction of the worm wheel axis and a direction parallel to the worm wheel axis.

15. Arrangement according to any one of claims 1 to 14, characterized in that common supporting surfaces of the base and top parts of the housing are penetrated by fixing means.

16. Arrangement according to claim 15, characterized in that said fixing means are screw means.

17. Arrangement according to claim 15, characterized in that the screw means extend parallel to the worm wheel axis.

18. Arrangement according to any one of claims 1 to 17, characterized in that the connecting projection axially penetrates the top and base parts of the housing.

19. Arrangement according to any one of claims 1 to 17, characterized in that the connecting projection paraxially penetrates the top and base parts of the housing.

20. Arrangement according to any one of claims 1 to 19, characterized in that the worm is provided at either end with a combined radial and thrust bearing.

21. Arrangement according to any one of claims 1 to 20, characterized in that the connecting projection is used to receive and support the machine.