Coupling device for torque-transmitting connection of two shafts

Abstract

Coupling device for torque-transmitting connection of two shafts with a first coupling member (10) which is connected to or integrally formed with a first shaft (14) and which has first axially extending projections (22), a second coupling member (16) which is connected to or integrally formed with a second shaft (20) and which has second axially extending projections (24) which engage in a positive-locking, torque-transmitting manner in the first axially extending projections (22), characterized in that the coupling device has a holding device (62) which is mechanically coupled to the first coupling member (10), wherein in a first position, in which the holding device (62) abuts against the second coupling member (16),The second coupling member (16) is pneumatically fixed in its axial position relative to the holding device (62) and the first coupling member (10) by a sealed volume (58) between the holding device (62) and the second coupling member (16), and in a second position, in which the holding device (62) is arranged at a distance from the second coupling member (16), the holding device (62) and the first coupling member (10) are axially movable relative to the second coupling member (16) by venting the sealed volume (58).

Description

[0001] The invention relates to a coupling device for torque-transmitting connection of two shafts with a first coupling member, which is connected to a first shaft or formed integrally with it, and which has first axially extending projections, and a second coupling member, which is connected to a second shaft or formed integrally with it, and which has second axially extending projections which engage in a positive-locking, torque-transmitting manner into the first axially extending projections.

[0002] Such coupling devices are required in a variety of applications to transmit torque from a drive shaft to an output shaft. One example is their use in transmitting torque from any drive to a dynamometer on a test bench. The coupling elements for torque transmission are often designed as external teeth and corresponding internal teeth, through which the rotation of the first coupling element, and thus of one of the shafts, is transmitted to the second coupling element or the shaft to be coupled. However, if one of the shafts is not secured in its axial position, these simple, positive-locking torque-transmitting couplings are susceptible to the risk that the two coupling elements will disengage from each other due to axial displacement of one of the shafts, thus preventing further torque transmission.In the aforementioned test rigs, it is common practice to bolt the shafts or coupling elements together to prevent axial displacement. However, such fastenings are both very complex to manufacture and difficult to disassemble. Therefore, various holding devices have become known for axially securing the two coupling elements relative to each other. These devices primarily employ spring elements attached to a holding device or one of the coupling elements, which spring into corresponding recesses on the second coupling element or the second shaft.

[0003] Such a holding device for a positive-locking torque-transmitting coupling, formed by a keyway connection, is known, for example, from US 3,611,748 B. The first shaft is mounted in a housing and axially secured. The second shaft, or the second coupling member, is axially secured relative to the first shaft, or the first coupling member, by a preloaded ball thrust piece located in the housing, which engages in a groove of the second shaft. A problem with such a mounting, however, is that the second shaft must be displaced relative to the housing with a high force to release it. In addition to the poor accessibility of such a shaft, undesirable forces and a loss of strength due to the necessary notching of the shaft also occur.

[0004] Accordingly, the disadvantages of known designs are that, when using spring elements, their removal is usually very complex and, especially in emergencies, often cannot be carried out quickly enough. Furthermore, these designs always involve a weakening of the coupling element or the shaft to be connected in order to provide space for the spring element to compress.

[0005] The task, therefore, is to create a coupling device for the torque-transmitting connection of two shafts, which allows for fixation without mechanical coupling, thus preventing mechanical weakening of the shaft and coupling ends. Furthermore, the creation and release of the axial fixation should be as simple as possible and can be carried out quickly and without additional tools, in order to allow for rapid intervention, especially in emergencies.

[0006] This problem is solved by a coupling device for torque-transmitting connection of two shafts with the features of main claim 1.

[0007] The coupling device according to the invention for torque-transmitting connection of two shafts comprises a first coupling member, which is connected to or integrally formed with a first shaft and which has first axially extending projections, and a second coupling member, which is connected to or integrally formed with a second shaft and which has second axially extending projections that engage in a positive-locking, torque-transmitting manner with the first axially extending projections. These projections can, for example, be designed as toothed sections, so that one of the coupling members with external teeth can be axially inserted into the other coupling member with complementary internal teeth.Naturally, torque-transmitting positive-locking connections such as tongue-and-groove connections or other non-circular designs of a first coupling element and a complementary design of the second coupling element are also possible. In addition to the shafts and coupling elements being constructed in one or more pieces, the coupling elements themselves can also be composed of several coupling parts or be formed in one piece. These coupling elements are thus designed in such a way that only a positive locking action acting in the radial and circumferential directions is formed, enabling torque transmission, while axial movement of the two coupling elements relative to each other remains possible.

[0008] To prevent such axial relative movement between the two coupling elements, the coupling device has an axially acting holding device which is mechanically coupled to the first coupling element. In this context, "mechanically coupled" means that the holding device rotates with the first coupling device during operation and can only perform defined relative movements to it, thus establishing at least a partial mechanical coupling of movements. In a first position, the holding device rests against the second coupling element, and the second coupling element is pneumatically fixed in its axial position relative to the holding device and the first coupling element by a sealed volume between the holding device and the second coupling element.This means that the holding device, which can also be multi-part, creates an airtight seal around the second coupling member, so that any relative movement of the second coupling member to the holding device generates a pressure difference that prevents this relative movement due to the pneumatic force. In a second position, the holding device is positioned at a distance from the second coupling member, allowing ventilation of the sealed volume and enabling axial movement of the first coupling member relative to the second. This ventilation can be initiated either by an external movement of the holding device or by other means, thus eliminating the need for the pneumatic holding force. In the first position of the holding device, axial movement of the two shafts connected via the coupling device is reliably prevented.The pneumatic holding force can be generated without additional aids and released very quickly in emergencies to decouple the shafts. This results in very short setup times. Furthermore, no machining of the shafts is required.

[0009] Preferably, axial movement of the holding device towards the second coupling member in its first position is limited by a stop on the first coupling member. This stop in the first position of the holding device thus also prevents minor movements of the first coupling member relative to the second coupling member, since the first coupling member is held in its position by the pneumatic holding force of the holding device.

[0010] Furthermore, it is advantageous if at least one elastic first seal is arranged between the holding device and the second coupling member, which in the first position seals against the second coupling member and the holding device and is elastically deformed in the axial direction. This elastic seal tightly confines the volume, so that when an attempt is made to detach the first coupling member from the second coupling member, the volume enclosed by the seal increases, creating a pressure difference that generates a force pulling the first coupling member towards the second coupling member.

[0011] In a further embodiment, at least one elastic first seal limits the volume around its outer circumference. The seal thus acts in the same way as a suction cup, which is attached at one side and encloses the corresponding volume at the opposite side. Through a movement of the second coupling element in the opposite direction to the holding device, the pressure differential increases in a known manner, thereby generating the holding force.

[0012] In an alternative embodiment, the enclosed volume is formed between the first seal and a second seal. In this embodiment as well, the volume increases during relative movement, thus creating the pressure difference that produces a holding effect.

[0013] In an alternative embodiment, the holding device has a first seal, wherein the first seal limits the volume radially inwards, and the second seal is fixed between the first and second coupling elements, the volume enclosed in the first position being formed between the first and second coupling elements. With a slight axial movement of the first coupling element away from the second coupling element, the space delimited by the seals increases, resulting in a pressure differential that draws the first coupling element back towards the second coupling element, thus retracting the first coupling element to its initial position.

[0014] In a further embodiment, the first coupling element has a radially inward-extending, annular wall with which the first coupling element is axially opposed to a closed wall surface of the second coupling element. In the first position of the holding device, a gap, at least partially forming the enclosed volume, is sealed radially inward between the annularly extending wall and the axially closed wall surface by the first seal. This gap forms the sealed volume, which increases when the first coupling element moves away from the second coupling element, thereby generating a restoring force that retracts the first coupling element back to its initial position.

[0015] Preferably, the second coupling member has a cylindrical projection that extends into a cylindrical recess in the first coupling member, at the end of which an annular wall extending radially inwards is formed, which is axially opposite the second coupling member. The second seal is a radial sealing ring arranged between the cylindrical projection of the second coupling member and an inner wall surface of the first coupling member that radially surrounds the recess. This radial sealing ring can be arranged in a groove of the first or second coupling member, particularly near the annular wall extending radially inwards, and thus reliably seals the volume radially outwards.In this way, the sealing effect can be prevented from being disrupted by slight axial movements of the first coupling member relative to the second coupling member, without having to maintain an additional contact force to deform the seal.

[0016] In a preferred embodiment, the first seal has a pin with which it is secured in a bore of the holding device. This simplifies the installation of the first seal and ensures a reliable attachment of the first seal to the holding device.

[0017] Furthermore, it is advantageous if the mechanical coupling of the holding device with the first coupling element is achieved by a mechanical guide for the holding device within the first coupling element. The holding device can thus only be moved in a defined manner towards the first coupling element, preventing unintentional disconnection.

[0018] In a further advantageous embodiment, at least one cam is formed in the first coupling member, in which the holding device is mechanically guided and movable between the first and second positions. In this context, "cam" refers to a contoured guide slot. Thus, after the second coupling member is engaged with the first, the holding device can be moved in a defined direction towards or away from the second coupling member by means of this cam.

[0019] In a further embodiment of the invention, at least one cam has a circumferential component and an axial component. When the retaining device is attached to the second coupling member and when it is detached from the second coupling member, the retaining device performs a combined rotational and axial movement relative to the second coupling member. This facilitates detachment by reducing the shear forces that occur during rotation.

[0020] Furthermore, it is preferred that the holding device has an outer actuating ring that surrounds the first coupling member and is connected via webs to an inner holding element to which the first seal is attached and which, at least in the first position, projects into an inner opening in the first coupling member. The outer actuating ring thus makes it possible to apply external force to move the holding device between the two positions, thereby coupling and uncoupling the holding device on the second coupling member. The holding device is mounted to the first coupling member by the coupling of the two coupling members and can be easily detached in the coupled state.

[0021] The mechanical coupling of the holding device to the first coupling element is preferably achieved via the webs that project into the cams of the first coupling element. The stop is thus created by the webs striking an axial end of the cams. In this way, a fully guided movement is achieved in a simple manner.

[0022] Advantageously, by rotating the outer actuating ring and guiding the webs along the cams, an axial movement of the holding device can be generated, allowing the holding device to be pneumatically attached to and detached from the second coupling member. This results in very simple operation of the holding device, whereby the holding force must be overcome by the pressure differential when releasing. This is facilitated by the leverage effect of the webs during the combined and guided rotary and axial movement.

[0023] In a further advantageous embodiment, the volume is fluidically connected to a switchable vent valve. Such a valve allows the holding force caused by the existing pressure difference to be released for easier removal by venting the volume to the outside. It is also conceivable to connect this vent valve to a vacuum source to generate an additional vacuum within the volume, which can be released by switching the valve.

[0024] This creates a coupling device for the torque-transmitting connection of two shafts with a holding device, which reliably prevents the coupled state of the two coupling elements from disengaging by applying a pneumatic holding force. The holding force can be applied and released in a particularly simple manner, allowing axial locking to be created and released in a very short time. This significantly reduces setup and teardown times. Machining and weakening of the connected shafts is completely unnecessary.

[0025] An embodiment of a coupling device according to the invention for the torque-transmitting connection of two shafts is shown in the figures and is described below.

[0026] The Fig. Figure 1 shows a side view of a coupling device according to the invention.

[0027] The Fig. Figure 2 shows the coupling device according to the invention. Fig. 1 in perspective, partially cropped view.

[0028] The coupling device according to the invention consists of a first two-part coupling element 10, which is connected to a first shaft 14 via a flange connection 12, and a second two-part coupling element 16, which is connected to a second shaft 20 via a second flange connection 18, as shown in Fig. 2 can be seen.

[0029] The torque transmission between these two coupling elements 10, 16 is effected via complementary features 22, 24 in the form of teeth whose teeth extend in the axial direction, so that torque can be transmitted via the engagement of the teeth. For this purpose, a circumferential external toothing is formed on the first coupling element 10 on an axially extending projection 26, which is formed on a first coupling part 28 of the first coupling element 10. The teeth of this external toothing serve as the first axially extending features 22, which engage with a corresponding internal toothing. The teeth of this internal toothing serve as the second axially extending corresponding features 24, which is formed on a first coupling part 30 of the second coupling element 16, which is designed as a ring gear.The ring gear has an axially extending annular projection 32, inside of which a second coupling part 34 of the second coupling member 16 is attached, to which the second shaft 20 is also attached.

[0030] This second coupling part 34 of the second coupling member 16 has a cylindrical, axially extending projection 36 in its radial interior, which projects into a correspondingly shaped inner cylindrical recess 38 of a second coupling part 40 of the first coupling member 10. The second coupling part 40 of the first coupling member 10 is fastened inside the annular, axially extending projection 26 of the first coupling part 28 of the first coupling member 10 and has a radially inwardly extending annular wall 42, which is arranged opposite an axially closed wall surface 44 of the cylindrical projection 36 of the second coupling part 34 of the second coupling member 16, with a narrow gap 46 formed between the wall surface 44 and the wall 42.

[0031] A first annular groove 48 is formed on a radially outer surface of the cylindrical projection 36 of the second coupling part 34 of the second coupling member 16, in which a sliding bearing 50 is arranged, over which the first coupling member 10 can be pushed onto the second coupling member 16.

[0032] Between the wall surface 44, which is opposite the radially inwardly extending wall 42 and the first groove 48, a second annular groove 52 is arranged on the outer surface of the cylindrical projection 36, in which a radial sealing ring 54 is arranged, which abuts a radial inner wall surface 56 of the second coupling part 40 of the first coupling member 10, which radially limits the recess 38.

[0033] The gap 46 forms a small volume 58 between the first coupling member 10 and the second coupling member 16, which can be tightly closed by a first elastically deformable seal 60, which is part of an axially acting holding device 62, and a second seal 64, which is formed by the radial sealing ring 54.

[0034] The first seal 60 is attached to a central, inner retaining element 66 of the retaining device 62, which projects through an inner opening 67 of the first coupling member 10. For this purpose, a pin 68 of the first seal 60 projects into a central bore 70 on the retaining element 66 and is either pressed in by deformation or, for example, attached by adhesive. The elastic first seal 60 has a circular area 72 facing the closed wall surface 44 of the second coupling member 16 and, in the illustrated first position of the retaining device 62, resting against this wall surface 44. Its radially outer edge 74 projects beyond the radially inner end of the annular wall 42, which extends radially inward, so that, in the first position of the retaining device 62, this section rests axially against the wall 42.In this first position, the elastic first seal 60 is axially compressed and reliably seals the gap 46 or the volume 58.

[0035] The retaining element 66 has three threaded bores 76 evenly distributed around its circumference, into each of which a first section 77 of a two-part web 78 is screwed. This first section 77 extends to an outer, annular projection 80 of the first coupling member 10, which extends to an axial side of the first coupling member 10 opposite the projection 26 and rests there against the projection 26 from the radial inside. A second section of the webs 78 is formed by screws 81, which are screwed into the internal thread at the end of the first sections 77 of the webs 78 and which each extend through a cam 82, of which three identical cams 82 are formed on the first coupling member 10.These cams 82 form a slot-like mechanical guide contour for the first coupling member 10 for the webs 78 and have a circumferential dimension and a significantly smaller axial dimension. The width of these cams 82 corresponds essentially to the width of the screw shanks 84 of the screws 80 of the webs 78, which are correspondingly narrower than the first sections 77. The screws 80 are inserted radially from the outside into corresponding holes 84 of an outer actuating ring 86, which radially surrounds the first coupling member 10, and, when tightened, rest with their screw heads 88 on corresponding bearing surfaces 87 surrounding the holes 84, so that the holding device is held in a concentric position with respect to the first coupling member 10.

[0036] During assembly, the retaining device 62 is first attached to the first coupling member 10 by first screwing the first sections 77 of the webs 78 to the retaining element 66 and then inserting the retaining element 66 into the opening 67 of the first coupling member 10. Next, the actuating ring 86 is placed around the coupling member 10 and the screws 80 are screwed into the holes 84 and through the cams 82 in the first sections 77 of the webs 78. The first shaft 14 can then be screwed onto the first coupling member 10. Following this, the second coupling member 16 can be pushed into the first coupling member 10 via the sliding bearing 50, and simultaneously its internal teeth can be slid onto the external teeth of the first coupling member 10. Finally, the second shaft 20 can be screwed onto the second coupling member 16. First, the positive-locking torque-transmitting coupling of the two shafts 14, 20 is created.

[0037] In this assembly, the holding device 62 is in its retracted position and thus with its webs 78 at the end of the cams 82 which has the greatest axial distance to the second coupling member 16 and is therefore in a position relative to the Fig. The opposite second position is shown in Figure 1. In this second position, there is an axial distance between the first seal 60 and the wall surface 44 of the second coupling member 16. In this position, the first coupling member can be moved axially relative to the second coupling member because there is no axial holding force.

[0038] By rotating the actuating ring 86 clockwise, the holding device is guided by the webs 78 along the cams 82 and performs a combined rotary and axial movement. This movement continues until the elastic first seal 60 abuts the wall 42 of the first coupling member 10 and the wall surface 44 of the second coupling member 16, where it is elastically compressed. The cam 82 prevents purely axial movement of the holding device 62 through the axially limiting wall surfaces. Instead, the first seal 60 and the second seal 64 completely seal the volume 58. If an axial relative movement of the first coupling member 10 to the second coupling member 16 occurs, the gap 46, or the volume 58, increases slightly, and the pressure inside the sealed volume 58 decreases accordingly.The resulting pressure difference generates a restoring force that moves the two coupling elements 10 and 16 back towards each other. Displacement of the holding device 62 with the second coupling element 16 is also prevented, since the wall of the cam 82 forms a stop 90 for the webs 78 and thus for the holding device 62, preventing it from being axially displaced relative to the first coupling element 10.

[0039] In an emergency or at the end of an experiment, for example, where the first shaft 14 is the shaft of a dynamometer and is connected via the coupling device to a drive shaft of an electric motor serving as the second shaft 20, the axial holding device 62 is released by rotating the actuating ring 86 counterclockwise from the outside along the cams 82. This removes the first seal 60 from the wall surface 44 of the second coupling member 16 via the retaining element 66, thus venting the volume 58. This venting eliminates the axial holding force between the first coupling member 10 and the second coupling member 16, allowing the two coupling members 10 and 16 to be axially separated, and subsequently, for example, another electric motor can be connected to the dynamometer.

[0040] Alternatively, instead of mechanically disconnecting and / or connecting, this can be done via a switchable ventilation valve 92, as shown schematically in dashed lines in the Fig. Figure 1 shows this. It is then connected to the volume 58 via a bore 94. With the vent valve 92 closed, the volume 58 remains sealed, while with the vent valve 92 open, the venting prevents a pressure differential from forming. The holding force could also be further increased by connecting a vacuum source, which could be connected to a third port of a corresponding vent valve 92.

[0041] In addition to the described designs, it would also be possible, for example, to design the first seal in such a way that it encloses a volume inside and thus acts like a suction cup, through which the corresponding axial holding force is applied.

[0042] This type of coupling device allows for quick and easy connection and disconnection of the coupling elements. Torque transmission is ensured even in the presence of vibrations, as axial displacement of the coupling elements relative to each other is reliably prevented. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] US 3,611,748 B

[0003]

Claims

[1] Coupling device for torque-transmitting connection of two shafts with a first coupling member (10) which is connected to or integrally formed with a first shaft (14) and which has first axially extending projections (22), a second coupling member (16) which is connected to or integrally formed with a second shaft (20) and which has second axially extending projections (24) which engage in a positive-locking torque-transmitting manner into the first axially extending projections (22), characterized by , that The coupling device has a holding device (62) which is mechanically coupled to the first coupling member (10), wherein in a first position, in which the holding device (62) rests against the second coupling member (16), the second coupling member (16) is pneumatically fixed in its axial position to the holding device (62) and to the first coupling member (10) by a sealed volume (58) between the holding device (62) and the second coupling member (16), and in a second position, in which the holding device (62) is arranged spaced apart from the second coupling member (16), the holding device (62) and the first coupling member (10) are axially movable to the second coupling member (16) by venting the sealed volume (58). [2] Coupling device for torque-transmitting connection of two shafts according to claim 1, characterized by, that an axial movement of the holding device (62) in the direction of the second coupling member (16) in its first position is limited by a stop (90) on the first coupling member (10). [3] Coupling device for torque-transmitting connection of two shafts according to claim 1 or 2, characterized by , that at least one elastic first seal (60) is arranged between the holding device (62) and the second coupling member (16), which in the first position seals against the second coupling member (16) and the holding device (62) and is elastically deformed in the axial direction. [4] Coupling device for torque-transmitting connection of two shafts according to claim 3, characterized by , that at least one elastic first seal (60) limits the volume (58) in the first position over its outer circumference. [5] Coupling device for torque-transmitting connection of two shafts according to claim 3, characterized by, that the enclosed volume (58) is formed between the first seal (60) and a second seal (64). [6] Coupling device for torque-transmitting connection of two shafts according to claim 5, characterized by , that the holding device (62) has the first seal (60), wherein the first seal (69) limits the volume (58) radially inwards and the second seal (64) is fixed between the first coupling member (10) and the second coupling member (16), wherein the volume (58) enclosed in the first position is formed between the first coupling member (10) and the second coupling member (16). [7] Coupling device for torque-transmitting connection of two shafts according to claim 6, characterized by, that the first coupling member (10) has a ring-shaped wall (42) extending radially inwards, with which the first coupling member (10) is axially opposite a closed wall surface (44) of the second coupling member (16), wherein in the first position of the holding device (62) a gap (46), which at least partially forms the enclosed volume (58), is sealed radially inwards by the first seal (60) between the ring-shaped wall (42) extending radially inwards and the axially closed wall surface (44). [8] Coupling device for torque-transmitting connection of two shafts according to claim 7, characterized by, that the second coupling member (16) has a cylindrical projection (36) which engages in a cylindrical recess (38) of the first coupling member (10), at the end of which the radially inward extending annular wall (42) is arranged which is axially opposite the second coupling member (16), and the second seal (64) is a radial sealing ring (54) which is arranged between the cylindrical projection (36) of the second coupling member (16) and an inner wall surface (56) of the first coupling member (10) which radially surrounds the recess (38). [9] Coupling device for torque-transmitting connection of two shafts according to one of the preceding claims, characterized by , that the first seal (60) has a pin (68) with which the first seal (60) is secured in a bore (70) of the holding device (62). [10] Coupling device for torque-transmitting connection of two shafts according to one of the preceding claims, characterized by , that the mechanical coupling of the holding device (62) with the first coupling element (10) is established by a mechanical guide of the holding device (62) in the first coupling element (10). [11] Coupling device for torque-transmitting connection of two shafts according to claim 10, characterized by , that in the first coupling member (10) at least a cam (82) is formed which forms the mechanical guide and in which the holding device (62) is guided to be movable for displacement of the holding device (62) between the first position and the second position. [12] Coupling device for torque-transmitting connection of two shafts according to claim 11, characterized by , that at least one backdrop (82) has an extent component in the circumferential direction and a component in the axial direction. [13] Coupling device for torque-transmitting connection of two shafts according to one of the preceding claims, characterized by , that the holding device (62) has an outer actuating ring (86) which surrounds the first coupling member (10) and which is connected via webs (78) to an inner holding element (66) to which the first seal (60) is attached and which, at least in the first position, projects into an inner opening (67) in the first coupling member (10). [14] Coupling device for torque-transmitting connection of two shafts according to claim 13, characterized by , that the holding device (62) is mechanically coupled to the first coupling member (10) via the webs (78) which project into the cams (82) of the first coupling member (10). [15] Coupling device for torque-transmitting connection of two shafts according to claim 14, characterized by, that by rotating the outer actuating ring (86) and guiding the webs (78) along the cams (82) an axial movement of the holding device (62) can be generated, by which the holding device (62) can be pneumatically attached to the second coupling member (16) and detached from the second coupling member (16). [16] Coupling device for torque-transmitting connection of two shafts according to one of the preceding claims, characterized by , that the volume (58) is fluidically connected to a switchable vent valve (92).

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