DE29508896U1 - Tooth coupling - Google Patents

Description

TOOTH COUPLING

The invention relates to a toothed coupling for, in particular, drive units of rail vehicles, consisting of two coupling hubs, each of which has a spherical external toothing, a coupling sleeve with an internal toothing at each end area and spring elements which apply an axially outward-directed force to each hub.

Such couplings, also known as curved tooth couplings, are used for the positive transmission of mostly high torques in drive systems, in which

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where radial, axial and/or angular displacements occur between the axes of the drive shaft and the output shaft. Due to the spherical shape of the external toothing of the two hubs, the coupling sleeve assumes an inclined position in which the sleeve axis runs at a - usually small - angle to the original position and to the two hub axes. In order to avoid arbitrary relative movements of the coupling sleeve and to stabilize the entire coupling system, spring systems are installed between the two hubs and counter bearings with preload on the coupling sleeve, which keep the coupling sleeve symmetrically stable. In known curved tooth couplings for drives of rail vehicles, either one relatively stiff helical compression spring per hub or a plurality of weaker helical compression springs evenly distributed over the circumference are used as spring elements for each hub. In both cases, the springs of both hubs are supported with preload on an inner counter bearing, which is designed, for example, in the form of a ring disk and is firmly connected to the coupling sleeve. The axially outer counter bearings of the springs are designed or attached to the corresponding hub.

If, with such a coupling type, the hub axles are displaced and thus the coupling sleeve is inclined or tilted, the spring preload causes the spring elements in the area of the outer angle to lengthen and the spring elements in the area of the inner angle to shorten. As the spring elements rotate when the coupling rotates, but the angular positions of the sleeves and hubs remain the same, each spring element experiences a certain amount of tension when the coupling is fully rotated.

Clutch first lengthens and then shortens. These cyclical changes in the spring length lead to cyclical fluctuations in the pressure forces exerted by the springs and are a cause of undesirable oscillations and vibrations in terms of wear and noise. Another effect that occurs at certain speeds and manifests itself in hard impact loads on the components as well as in intensive noise has been identified as being particularly harmful. The functional connection between the dynamic behavior of the spring elements and the speeds of the clutches has been determined as the cause of these harmful effects. If the clutch speeds exceed a critical range for the spring element used, the respective spring element can no longer precisely follow the rapidly changing distance changes between its two fixed counter-holders due to its inherent rigidity or spring characteristics and enters its own vibration state, the frequency of which does not match the frequency of the distance changes corresponding to the speed. As a result, the spring element or the entire spring organ performs natural vibrations, which in extreme cases lead to the spring ends briefly lifting out of their holders or from their counterholders and thus to hard impacts when contact is made again.

The object of the invention is to create a toothed coupling which, when transmitting large torques and relatively high speeds as well as with larger, changing axis offsets during operation, runs with little oscillation and vibration and in which, in particular, the adverse effects caused by spring elements are avoided.

This object is achieved according to the invention in that at least in one coupling half the spring elements are supported on at least one counterholder, which adjusts itself automatically in the event of an offset of the secondary axes, so that the length of the spring elements over the circumference per revolution of the coupling remains approximately constant.

The basic idea of the invention is the decoupling of the spring system formed by the spring elements from the other components of the coupling that are influenced by the axial displacement, i.e. the two hubs and the coupling sleeve, in such a way that cyclical changes in the length of the spring elements over the circumference during one rotation of the coupling are avoided and the spring forces generated remain constant regardless of the radial and/or angular displacement of the hub axes and thus the inclination of the coupling sleeve. There are several options for implementing this knowledge in practical solutions. One of these possibilities is to design at least one of the counterholders of the spring elements that interact with the respective hub to be spatially movable relative to the hub, so that if the hub axes are offset relative to the support surface formed on the associated hub, it automatically adjusts itself in such a way that the shortening on the inner angle side as well as the elongation on the outer angle side of the spring elements used are compensated and the pre-tensioned spring element is thus kept constant in its overall length. A practical implementation of this concept is characterized by the fact that one of the counterholders of each spring element has a spherical, preferably spherical, support surface that is in sliding contact with a likewise spherical support surface of a ring that is on the inner end of the respective hub or on the coupling sleeve.

Each hub is subjected to the force of a separate pre-stressed spring element, which rests with its outer end on the associated hub and with its inner end on a counter bearing in the form of an annular disk arranged approximately in the middle transverse plane of the coupling sleeve. The spring element can be designed in the form of a rigid helical spring or a set of springs evenly distributed over the circumference. The coupling sleeve is preferably made up of two halves which are flanged together in their central area.

In order to enable axial displacement movements of the adjustable counterholder when the axial offset of the hubs occurs or changes, the adjustable counterholders are expediently arranged in the coupling sleeve so that they can be displaced axially and are preferably supported or guided in sliding contact via a spherically shaped contact surface on the inner wall of the coupling sleeve. This spherical outer surface of the two adjustable counterholders can be designed in the form of an outer annular bead that is molded onto the axially inner sleeve-shaped end part of the counterholder designed as a stepped bush. In order to facilitate the relative displacement movements of the counterholder on the hub and also on the inner wall of the coupling sleeve, lubrication channels are provided through which the respective sliding surfaces are supplied with a suitable lubricant.

The use of two stiff helical compression springs with a relatively large inner diameter prevents the generation of oscillations and vibrations caused by cyclical changes in the length of the springs. However, these relatively large helical compression springs must be manufactured very precisely

and positioned precisely to avoid oscillations or vibrations caused by imbalance, for example.

A more favorable development of the invention in this respect is characterized in that two sets of relatively weak helical compression springs are used as spring elements, which are evenly distributed over the circumference and secured in position parallel to the axis in the coupling sleeve and whose inner ends are held in cylindrical recesses in an inner ring attached in the middle transverse plane of the coupling sleeve. The axially outer ends of these helical compression springs are supported in cylindrical recesses in the adjustable counterholder, which is axially displaceable relative to the inner ring and secured against relative rotation. This adjustable counterholder expediently has an annular axial projection with a spherical support and sliding surface on its end face facing the hub.

Another possibility for the practical implementation of the technical concept underlying the invention is that a central recess is provided in each hub in which a spring element, a counterholder and a pressure tappet mounted on the counterholder in a tiltable manner are arranged, whereby the pressure tappet is supported or attached to a component firmly connected to the coupling sleeve, in particular a central transverse wall. In this arrangement, the two spring elements, each arranged axially centered in the hubs, always act in the direction of the hub axis, whereby the adjustable counterholder can swivel or tilt relative to the pressure tappet attached to the transverse wall in the axis of the coupling sleeve due to the corresponding design of its support.

movements according to the inclinations resulting from the angular displacement of the hub axes. In a variation of this concept, instead of the one helical compression spring arranged in the hub centered on the axis, a set of spring elements consisting of several compression springs can be used, whereby these spring elements are evenly distributed over the circumference and are supported with their axially inner ends on a common adjustable counterholder, which is articulated in its central part via a single-spherical support on the transverse wall of the coupling sleeve.

Further special features and advantages of the tooth coupling according to the invention can be found in the following description of preferred embodiments shown in the drawing. They show:

Fig. 1 shows a first embodiment of the curved tooth coupling according to the invention in the neutral position in a schematic axial section;

Fig. 2 the curved tooth coupling according to Fig. 1 in a

Operating condition with radially and axially offset hub axes;

Fig. 3a to 3c show sectional views of a further embodiment of a curved tooth coupling according to the invention;

Fig. 4 shows in axial section a further embodiment of the invention in the neutral operating state;

Fig. 5 the curved tooth coupling according to Fig. 4 with radially and axially offset hub axes;

Fig. 6 one half of another embodiment of a

curved tooth coupling according to the invention in axial section;

Fig. 7 shows an axial section of a curved tooth coupling of the state of the art.

To better understand the invention, the known curved tooth coupling shown in Fig. 7 in a schematic axial section is described first, which - like the embodiments designed according to the invention according to Fig. 1 to 6 - is designed for use in drive units of rail vehicles, in particular in electric railcars. This known curved tooth coupling contains a coupling sleeve 2 and two coupling hubs 3, 4, which are attached to the end journals of a drive shaft 5 and an output shaft 6. The coupling sleeve 2 consists of two halves 7, 8, which are flanged together in a central transverse plane by screw connections 9. A profiled cover 10, 11 is attached to each of the two axially outer end faces of the coupling sleeve 2 by screw connections. An annular disk 12, 13 is attached to the axially inner end face of each coupling half 7, 8, each of which forms an axially inner fixed counter bearing for a spring element in the form of a helical compression spring 14, 15. The axially outer end of each of the two helical compression springs 14, 15 is supported on an annular shoulder 16, 17, which is formed on the inner axial end part of the respective hub 3, 4. Each hub 3, 4 also has a curved toothing 18, 19 on its outer circumference, which is connected to an internal toothing

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20, 21 engage in the axially outer end region of the two halves 7, 8 of the coupling sleeve 2.

In the operating state shown in Fig. 7, the axes of the two shafts 5, 6 and thus also of the two hubs 3, 4 are offset radially parallel by the amount R, so that the connecting line of the two points M is inclined at an angle α. The points M are the intersection points of the respective hub axis 34 or 35 with the line of engagement E of the gears and the connecting line of these two points M coincides with the axis of the coupling sleeve.

Due to the radial offset of the two hubs 3 and 4 and the resulting inclination of the coupling sleeve 2, the axial distances between the counter bearings 12, 16 and 13, 17 also change over the circumference and thus also the effective length of the helical compression springs

14 and 15. Thus, the helical compression spring 14 is shorter in the upper part in Fig. 7 than in the lower part and conversely, the helical compression spring 15 is longer in the upper circumferential area in Fig. 7 than in the lower circumferential area. When the coupling rotates, the length of the two helical compression springs 14 is constantly changing.

15 between the two extreme values shown. Due to the spring characteristics, in particular the necessary rigidity of the two helical compression springs 14, 15, natural vibrations of these two helical compression springs occur at certain clutch speeds, the frequency of which does not match the clutch speed that determines the length changes. As a result, these natural vibrations can lead to the helical compression springs 14, 15 lifting off their respective seats in some areas and, after a corresponding partial rotation,

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hit the seat again, which leads to considerable mechanical stress and also to intense noise.

In the curved tooth couplings according to the invention shown in Figs. 1 to 6, the components corresponding to the design according to Fig. 7 are identified with the same reference numerals. The essential difference between the design according to Figs. 1 to 3 and the curved tooth coupling described above is that the two axially outer counter bearings for the spring elements 14, 15 are designed as separate, automatically adjustable components 25, 26, which in the design according to Figs. 1, 2 have the shape of a stepped bush, the hollow cylindrical part of which has an annular bead 23, 24 at its inner end, which rests with a spherically shaped outer surface on the inner peripheral surface of the respective half 7 or 8 of the coupling sleeve 2.

At the axially inner end part of each hub 3, 4, a ring 30, 31 is permanently attached in an annular shoulder, which has a spherically curved outer surface 32, 33 that slopes down towards the center of the coupling. The centers M of these spherically curved outer surfaces lie on the respective hub axis 34, 35, namely at their intersection with the respective transverse planes E, which run through the central contact points of the gears 18, 20 and 19, 21.

From a comparison of Fig. 2 and 7, in which an operating state with radially offset hub axes is shown, the mode of operation of the curved tooth coupling according to the invention according to Fig. 1, 2 compared to a known coupling becomes clear. In both cases, the

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radial offset of the two hub axes is approximately the same size, whereby in the operating state according to Fig. 2 the two hubs 3, 4 have also been moved apart by a maximum amount A. As shown in Fig. 2, the length of the two helical compression springs 14, 15 is not changed over the circumference by the radial axis offset R of the two hubs 3, 4 and the resulting inclination of the coupling sleeve 2, because the spherically shaped projections 27, 28 move on the spherically shaped ring disks 30, 31 in the manner shown in Fig. 2. Thus, when the coupling arrangement rotates, no cyclical changes in the length of the spring elements occur, which are the cause of natural vibrations of the spring elements in the known design according to Fig. 7. The effective length of the two helical compression springs 14, 15 is only changed by the amount A by which the two hubs 3, 4 are moved apart. As shown, the displacement angle ß by which the contact line between the two spherical components 25 and 30 or 26 and 31 is adjusted corresponds to the angle α between the longitudinal axis 36 of the coupling sleeve 2 and the respective hub axis 34 or 35.

The design according to Fig. 3a to 3c corresponds in its essential structure to the curved tooth coupling according to Fig. 1 and 2, so that the same components are again provided with the same reference numerals.

However, only one half of the coupling is shown in Fig. 3a, as the other half of the coupling is symmetrical and works in the same way. What is different about this coupling design according to Fig. 3a is that here instead of a single helical compression spring 14, 15 extending helically over the entire circumference according to

Fig. 1, a plurality of separate helical compression springs 40 are used as the spring element, each of which is accommodated with its one end in a recess 41 in an annular disk 42. The other ends of the cylindrical helical compression springs 40 are seated in recesses 44, which are formed in a further annular disk 43, which forms the adjustable counter-holder for the spring element. The axially inner annular disk 42 is fastened to the half 8 of the coupling sleeve 2 in such a way that its left-hand end face in Fig. 3a is flush with the separating surface of this coupling half 8 or is set back from it. The ring disk 43 forming the adjustable counterholder is positioned axially displaceable and rotationally fixed via pins 45 relative to the ring disk 42 forming the axially inner counterholder (see Fig. 3b, 3c) and has on its radial outer edge several spherical projections 46 evenly distributed over the circumference, which rest against the inner wall of the coupling sleeve 2 in sliding contact. On the right-hand side of the ring disk 43 in Fig. 3a, 3b, an axial ring projection 47 is formed, which has a spherical surface 48 pointing radially inwards in its end region. With this spherical surface 48, the ring projection 47 rests against the spherical radial outer surface 33 of the ring 31 attached to the hub in sliding contact.

The functionality of the design shown in Fig. 3a corresponds essentially to that of the curved tooth coupling according to Fig. 1 and 2, whereby, however, the ring disk 43 forming the adjustable counter bearing for the helical compression springs 40 is secured against rotation in the coupling sleeve 2 by the axial pins 45, which are fixed in the ring disk 42 and slide in recesses 49 of the axially adjustable ring disk 43

Furthermore, the independent effect of each individual helical compression spring 4 0 can prevent the influences acting in the circumferential direction, which occur when using only a single stiff helical compression spring as shown in Fig. 1.

The curved tooth coupling shown in Fig. 4 and 5 corresponds in its basic structure to the version according to Fig. 1 and 2, so that again the same components are provided with the same reference numerals. In this version according to Fig. 4, however, two continuous, dimensionally stable partition walls 50, 51 are fastened between the two halves 7 and 8 of the coupling sleeve 2, e.g. by screws, in the center of which a plunger 52, 53 with a widened head 54, 55 is supported. These plungers 52, 53 have a tapered end 56, 57, e.g. in the form of a tapered cone, with which the pressure plunger is supported in a correspondingly shaped recess 58, 59 of an adjustable counterholder 60, 61 for a helical compression spring 62, 63. The pressure tappets 52, 53 and the counterholders 60, 61 are designed in such a way that the contact between the two is in the area of the intersection of the respective hub axis 34, 35 with the respective transverse plane E, which runs through the central contact points of the gears 18, 20 and 19, 21. The helical compression springs 62, 63, the counterholders 60, 61 and the shafts of the pressure tappets 52, 53 are each accommodated in a central recess 64, 65, e.g. in the form of a blind bore, which is formed axially centered in the hub or, in the present case, in one of the shafts 5, 6.

With a radial axis offset R of the two hubs 3, 4 or the shafts 5, 6 as shown in Fig. 5, only

This allows a corresponding tilting movement of the two pressure tappets 52, 53 in their support point 56, 57 in the respective recess 58, 59 of the counterholder 60, 61, without this affecting one or the other helical compression spring 62 or its effect. This also avoids the disadvantageous effects of cyclical changes in the length of the spring elements and the resulting natural vibrations of the system.

The curved tooth coupling according to Fig. 6 corresponds in its functional principle to the design according to Fig. 4 and 5. Here too, a spring element designed as a pre-tensioned helical compression spring 63 is arranged in the central area of the coupling half shown and is supported at one end on an adjustable counterholder 61, which allows tilting movements via a spatial joint. In this design according to Fig. 5, the fixed counterholder of the helical compression spring 63 is formed by the transverse wall 51 and a guide bolt 66 attached to it. The adjustable counterholder 61 is designed in the form of a guide pin for the axially outer part of the helical compression spring 63, which is supported on an end collar 67. A central recess 68 in the counterholder 61 ends in a concave base 69, which represents a support bearing for the tapered end part 70 of a central pressure bolt 71 attached to the shaft 6. The tapered end part 70 of the pressure bolt 71 and the concave, e.g. conical, bottom 6 9 act as a so-called spatial joint.

The invention is not limited to the embodiments shown. For example, different measures of one embodiment shown can be applied to another variant shown. This applies, for example, to the use of a

A plurality of individual spring elements evenly spaced around the circumference, which can also be used in the embodiments according to Fig. 4 to 6 instead of the central helical compression spring 62, 63, in which case this plurality of helical compression springs should be supported on a disk-shaped component which is accommodated in a spherical shell bearing fastened centrally to the respective transverse wall 50, 51.

Claims (14)

IC « &igr; < m &igr; CLAIMS 1. Gear coupling, in particular for drive units of rail vehicles, consisting of - two clutch hubs (3, 4), each with a crowned external toothing (18, 19), - a coupling sleeve (2) with an internal toothing (20, 21) at each end area and - spring elements (14, 15) which keep the coupling sleeve (2) axially symmetrical with respect to the coupling hubs (3, 4), characterized in that - at least in one coupling half, the spring elements (14, 15; 40; 62, 63) are supported on at least one counterholder (25, 26; 43; 60, 61) which is automatically adjustable in the event of an offset of the hub axes (34, 35) and thereby keeps the length of the rotating spring elements approximately constant over the circumference per revolution. 2. Tooth coupling according to claim 1,
characterized, that the spring elements (14, 15; 40; 62, 63) are guided coaxially centered either to the axis (36) of the coupling sleeve (2) or to the respective associated hub axis (34, 35) even if the hub axes (34, 35) are offset. 3. Tooth coupling according to claim 1 or 2, characterized in that that the adjustable counterholder (25, 26; 43; 60, 61) can be automatically displaced coaxially relative to the coupling part (2; 3, 4) guiding the spring elements. 4. Tooth coupling according to one of claims 1 to 3, characterized in that that each spring element consists of a rotationally symmetrical spring element (14, 15), e.g. a helical spring, the ends of which are supported on the one hand on the coupling sleeve (2) and on the other hand on the coupling hub (3) via an annular counterholder (12, 13; 25, 26), with at least one of the counterholders being automatically adjustable via a spatial joint. 5. Tooth coupling according to one of claims 1 to 3, characterized in that the spring element consists of several spring elements (40) distributed over the circumference, e.g. of helical springs, the ends of which are supported on the one hand on the coupling sleeve (2) and on the other hand on the associated hub (3, 4) via an annular counterholder (42; 43), with at least one of these counterholders (42 or 43) being automatically adjustable via a spatial joint. 6. Tooth coupling according to claim 5,
characterized, that each spring element is guided in cylindrical recesses (41, 44) aligned with one another in the counterholders (42, 43). 7. Tooth coupling according to claim 5 or 6, characterized in that the ring-shaped, spatially articulated counterholder (43) is guided on pins (45) in a rotationally fixed and axially displaceable manner and has a spherical sliding and supporting surface (48) on one part (47). 8. Tooth coupling according to one of claims 1 to 7, characterized in that the spatially adjustable counterholder (25, 26; 43) is supported in a spatially articulated manner on the associated coupling part (2; 3, 4) via spherical sliding surfaces (27, 28; 48). 9. Toothed coupling according to claim 8, characterized in that at least one sliding surface of the sliding surface pair (27, 32; 28, 33; 48, 33) is spherical, with its center point M lying in the region of the intersection point of the associated hub axis (34, 35) with the axis (36) of the coupling sleeve (2). 10. Tooth coupling according to one of claims 1 to 9, characterized in that the adjustable counterholder (25, 26; 43) is designed in the form of an annular bushing and has a spherical outer surface (23, 24; 46) resting on the inner wall of the coupling sleeve (2). 11. Toothed coupling according to one of claims 1 to 3, characterized in that the spring element (62, 63) is arranged in the central region of the coupling and at least with its one End is supported on the adjustable counterholder (60, 61). 12. Tooth coupling according to claim 11,
characterized, that the adjustable counterholder (60, 61) is supported on the associated coupling part (2; 3, 4) via a spatial joint (56, 58; 57, 59). 13. Tooth coupling according to claim 11 or 12, characterized in that the spring element (62; 63) designed as a helical spring is arranged in a central, axis-centered recess (64; 65) of the associated hub (3; 4) or the associated shaft (5, 6), in which the adjustable counterholder (60, 61) is also guided coaxially. 14. Tooth coupling according to one of claims 1 to 13, characterized in that that at least one of the sliding surfaces is hardened and/or lubricated.