DE3517681A1 - Articulated shaft for play-free torque transmission, with flexible shaft joints for compensating angular and axial misalignment - Google Patents

Abstract

The invention relates to an articulated shaft with flexible shaft joints which consist of disc- or cone-shaped diaphragms which are flexible as regards angular and axial deformations and stiff with regard to torsional and radial deformations. The diaphragms are reinforced against local instabilities (shear bulges) by profiles on the (thin) diaphragms, the profiles preferably being arranged in a ring around the centre and preferably being wave-shaped in their cross-section. This shaping furthermore provides additional elasticity for the desired mobility. The diaphragm is preferably manufactured from fibre-reinforced plastic in laminate form and preferably in one piece with an associated shaft section (likewise composed of fibre-reinforced plastic), giving one-piece articulated shafts.

Description

Gelerawelle for backlash-free torque transmission

elastic corrugated bellows to compensate for angular and axial displacements 3 v E T, B UT tt G Cardan shaft with elastic cardan joints for backlash-free torque transmission to compensate for axial and angular errors, preferably made of fiber-reinforced plastic manufactured in one piece with the shaft. The invention relates to a cardan shaft with elastic universal joints, which are made of disc or cone-shaped membranes that are soft against angular and axial deformations and against torsional and radial deformations stiff.

The membranes are resistant to local instabilities (shear dents) preferably arranged in a ring around the center point, preferably in their cross-section Wavy profile of the (thin) membrane stiffened.

This shape also creates additional elasticity for the desired mobility.

The membrane is preferably made of fiber-reinforced plastic Laminate shape and preferably with an associated corrugated shaft (also made of fiber-reinforced Plastic) manufactured in one piece, so that one-piece cardan shafts are created.

Conventional cardan shafts are usually made up of a large number of individual parts assembled, even the individual joints usually consist of several individual parts.

Where one-piece joints are described, these are through their complicated design is laborious in several operations or from prefabricated ones To manufacture individual parts (cf. DE 3132 877 A1, DE 3132 533 A1) and cannot be manufactured in one piece with the shaft.

A described cardan shaft with an integrated joint (DE 3229 209) has a slit in the joint that is unsuitable for the transmission of torsional moments Shaping on what the material utilization worsened, so that the Advantage of the design, which is very simple in principle, due to higher material and weight requirements and, under certain circumstances, only inadequate function is bought.

Another suggestion, the entire shaft in the shaft is evenly flexible to design (DE 31 43 194 Al), has the disadvantage that the forced Softness of the whole shaft the critical speeds become low when larger Bending angles or paths are required. In addition, to achieve a sufficient Longitudinal elasticity, additional mechanical components are necessary, as the proposed method of compressing the shaft lengthways beyond its stability limit is incompatible is with higher operating speeds.

The arrangement of beads in the shaft shaft as an elastic joint (DE 33 20 760 Al, US-PS 4,173,128) leads only to low angular wi axial mobility, in addition, mounting flanges are not integrated.

The invention was therefore based on the object of a universal joint create, which can be manufactured economically through a simple shape and is also suitable, together with the associated shaft shaft, in to be manufactured in one piece and which, due to its design, can be used well the material strength for the transmission of a torque bar.

According to the invention this object is achieved in that the joint from consists of at least one substantially disc-shaped or conical membrane #, the preferably at the end of the shaft, which is preferably designed as a cylindrical tube is attached, with both the shaft shaft (1> and the membrane preferably made of fiber-reinforced plastic and in one piece together on one relatively simple device can be made.

The membrane takes on the joint function through elastic deformation (Compensation of angular and axial movements), whereby they counteract radial misalignment and torsional deformation has a high rigidity, so that high critical speeds can be achieved.

To stiffen against instability (shear dents) and to increase the desired elasticity, the membrane with a preferably ring-like concentric arranged to the center of the shaft, preferably wave-shaped in their cross-section, E.g. profiling (3) formed from circle subsections.

The membrane preferably goes with a suitable radius of curvature, e.g. the radius of the stiffeners, directly into the wall of the cylindrical tube, which forms the shaft shaft.

As a rule, however, the wall thickness of the pipe has to be increased by additional Layers of laminate, compared to which the membrane is raised, as this is usually the case no additional reinforcement runners are provided by the shaping.

Only if extreme demands are placed on lightweight construction can It is worthwhile to also shape the pipe with a profile (3) corresponding to that of the membrane (The position of the stiffening shafts is most appropriate for manufacturing reasons selected roughly along the shaft shank) to stiffen against shear dents.

Usually, however, the choice of a larger wall thickness is more economical Way to a sufficient rigidity.

The design of the shaft shaft against breakage due to shear instability also offers advantages: If the critical stress at which the buckling begins is exceeded, the shaft will be destroyed if the load is slightly below that However, full fatigue strength is still guaranteed, as it is at the breaking point of the material there is still a sufficient safety margin.

Therefore, the shaft can be used as a predetermined breaking point between two, ham insert that the load of the two aggregates over a set In addition, it prevents a normal load just below this Limit there is a risk of gradual destruction of the shaft.

The exact setting of the stability limit can be experimentally check, because if you proceed carefully, the load until observable beginning of the buckling is possible without overloading the material.

If the membrane is attached to the end of the shaft, it is suitable at the same time as a mounting flange. If this fastening is moved to the outside, so that the flange surrounds the actual elastic membrane in a ring shape, so results a particularly simple production, since no undercuts occur.

Are, e.g. to obtain small connection dimensions, undercut Shapes are necessary, so you can work with lost cores, for example made of foam will.

This procedure is also recommended when a shaft has a joint should be provided at any point on the shaft. Will at least two membranes are connected by a short piece of shaft, creating a compact one Coupling that can also connect shafts whose axes do not intersect.

The invention is illustrated below with the aid of a few examples from the large number possible designs explained in more detail.

1 shows an embodiment which is particularly simple in terms of production technology of the invention, shown is one end of the shaft shaft (1), as a simple Round tube is formed, with the molded Nembrangelenk (2) and a stepped Mounting flange (4). The membrane (2) has an undulating profile (3) provided. The cavity created by the removal of the mounting flange (4) (6) allows full mobility of the joint even with a flat mating flange (5), even if the mating flange still has elevations, e.g.

Screw heads.

The top view of the shaft end (Fig. 2) leaves the concentric Recognize the arrangement of the stiffening shafts (3).

The entire shaft can be manufactured in one piece.

Fig. 3 shows an embodiment of the invention in which the universal joint is provided in the course of the shaft.

Production in one piece is also possible here, but it does exist also the possibility of two shaft ends according to FIG. 1 by screws or Glue to join together.

Fig. 4 shows an embodiment of the invention in which the fastening flange (4 ') is drawn inwards in order to achieve a smaller radial space requirement.

Fig. 5 shows a membrane (2) according to the invention, which as an elastic Coupling acts and an outer (4) and an inner (4 ') mounting flange having.

Fig. 6 shows two membranes (2) which form an elastic coupling combined with internal mounting flanges (4 ') and a short pipe section (1') are.

A special embodiment of the invention is shown in FIGS. 7 and 8.

Here is a combination of a very large shaft diameter with a very low wall thickness selected. This design allows extremely high critical Revolutions, especially if at a high level of diagonal or circumferential direction on the shaft running fibers can be dispensed with and the shaft from is preferably built up approximately longitudinally aligned fibers.

In the case of a circular shaft cross-section, however, this would be very high there is a risk of shear instabilities, so that a stiffening is necessary, the however, it may only cost a little weight.

This is why the shaft (1 ') is also characterized by an undulating profile (3 ') stiffened. Because the shaft diameter in relation to the transmitted torque is very large, the membrane (2) is arranged within the tube (1 ') and carries an inner mounting flange (4 ') or other mounting bracket.

In a further embodiment of the invention, the cardan shaft (0) coordinated in terms of their stiffness through the design of the membrane joints, that supercritically running and thus self-centering units (e.g. centrifuges) directly through the cardan shaft without the need for additional support bearings.

For this purpose, the shaft on the relatively rigidly mounted second Unit, e.g. the drive motor (8), attached and supported at its second end the centrifuge (9) or the like.

The shaft and its joints must therefore transfer the static loads, with vertical axis mainly axial load, and they have to go through their rigidity generate a critical speed that can be passed safely can. Both are due to the very variable design options of the invention Wellengelehks easily possible.

Another focus of the invention lies in the manufacture of the Cardan shafts, which can be made by two methods: 1. Fiber winding method 2. Tissue winding process In the fiber winding process, first of all, as in the case of rotational solids Usually, fiber strands (preferably pre-soaked with synthetic resin) on the mandrel for the Shaft shaft and the fittings for the membranes, which are preferably conical for this purpose are wound up in compliance with the appropriate angles.

In the fabric winding process, fabric mats are also pre-soaked can be (prepregs or so-called wet prepregs, which are freshly impregnated with synthetic resin wound on the mandrel. The membrane that is preferred in this case is disc-shaped, is made from other blanks.

In the case of a shaft according to FIG. 1, these blanks already have the hole for the shaft shaft (1), but taking into account the necessary overlap between the shaft and the membrane, which must ensure the power transmission.

The fiber angles on the shaft are made by warping a 00/900 Tissue and / or introduction of unidirectional tissues as required Stiffnesses and stiffness directions are optimized while the fibers are on the disc are preferably oriented so that an approximately isotropic material behavior is achieved. This can be achieved, for example, with two symmetrical 0 ° / 90 ° layers of fabric that are offset from each other by 450.

Fabric that has not been pre-soaked is soaked in synthetic resin after it has been applied, as is common practice with the laying on of hands.

Difficulties can arise with both wound fibers and fabrics occur when the fibers are to follow three-dimensional shapes, e.g. due to the profiling (3) of the membranes (2) are necessary.

Therefore, the fibers are until the resin hardens by means of a pressure piece (20), which is adapted to the desired shape of the profile (e.g. 3, 4 or 1 ') is adapted, pressed against the mold (12, 14) so that the contour is accurate adhered and excess resin is squeezed out to the sides.

The pressure piece (20) is preferably made of a highly elastic material, e.g., silicone rubber; as a result, the design does not need to be completely to be exact, the same pressure piece can be used to produce different components Wall thickness can be used and its production can be achieved by simply casting the corresponding fitting (e.g.

12, 14).

The pressure can be applied e.g. via a rigid counter plate (19) will.

To remove the cured component from the mold, the end disks are first (12, 14), if present, removed from the mandrel (11), e.g. 3. by means of an integrated Push-off device (18).

For the subsequent demolding of the shaft shaft are suitable Two methods in particular: 1. Thermal stresses are created by temperature changes between the shaft shaft (1) and the mandrel (11) that detach the two parts from each other enable.

2. Axial pressure is applied to one of the shaft ends. Because fiber composite materials, especially with diagonal fiber reinforcement, have a high Poisson's ratio have, this causes a widening of the shaft shaft (1), which leads to the detachment favored by the mandrel (11).

When applying the axial pressure must. on the sensitivity of the Shaft end should be taken into account, especially if this is a thin-walled membrane joint (2) is formed.

Therefore, the pressure is preferably via one of the diaphragm shapes (2, 3) adapted pressure piece (21) applied.

Once the shaft has been detached from the mandrel, further demolding is possible mostly relatively simple, even if the mandrel is cylindrical, so that the mandrel is drawn out Material can be produced without further surface treatment.

This is particularly important for small series production, as the The mandrel determines the length of the PTO shaft.

Removable cores (17) are either after the molding has hardened destroyed or pulled out completely, if they are elastic enough for this.

Claims (1)

PATENT CLAIMS 1) Cardan shaft for the transmission of torques and to compensate for angular and axial misalignment between the driving and driven shaft, characterized in that the shaft shaft (1) is preferably designed as a hollow cylinder and the required angular and axial mobility through elastic deformations at least one substantially disk-shaped or conical membrane (2) is achieved is, and that the entire propeller shaft is preferably made in one piece. 2) propeller shaft according to claim 1), characterized in that the entire Cardan shaft is preferably made of fiber-reinforced plastic. 3) cardan shaft according to claim 1) or 2), characterized in that the membrane (2) forming the joint to achieve sufficient elasticity made of a thin material, preferably fiber-reinforced plastic, and against instability (shear dents) and to further improve deformability by a preferably ring-like concentric to the center of the shaft, is stiffened in its cross section preferably wave-shaped profiling (3). 4) cardan shaft, preferably according to one of claims i) -3), characterized marked that. the diaphragms functioning as a joint are designed as fastening flanges (4) at the same time are. 5) cardan shaft according to one of the preceding claims, characterized in that daa membranes (2) are arranged inside the shaft as an intermediate joint (7). 6) Cardan shaft according to one of the preceding claims, characterized in that that the shaft shaft (1) designed as a hollow cylinder by targeted fiber reinforcement, e.g. mainly diagonally aligned fibers for high torsional moments or predominantly Ins oriented fibers for high speeds, tailored to the conditions of use will. 7) cardan shaft according to one of the preceding claims, characterized in that because the shaft shaft, which is otherwise preferably designed as a circular hollow cylinder (1 ') for special requirements, e.g. extremely high critical speeds at high Torsional moment, through preferably longitudinally oriented, preferably in their cross-section corrugated profiling (3 ') is stiffened against instability, e.g. by a to combine very large diameters with a correspondingly small wall thickness can. 8) wave, e.g. 3. according to one of the preceding claims, characterized in that that the shaft shaft, which is preferably designed as a hollow cylinder, by the vote of diameter and wall thickness is designed in such a way that it is still ahead in the event of overload Reaching the strength limit of the material by instable # -tit fails, so that the shaft as a predetermined breaking point to avoid damage to the shaft coupled machines functions without having to deal with loads below this load limit the risk of fatigue failure, e.g. due to oscillating or changing loads, would exist. 9) #wave, preferably according to claim 8), characterized in that that by choosing an asymmetrical arrangement of the fiber reinforcement the transferable Lasteiifor both directions of rotation of the shaft can be set differently. 10) cardan shaft according to one of the preceding claims, characterized in that that the joints for the storage of units (9) which center themselves during operation, e.g. centrifuges, so that their rigidity is matched to the static Accept the load and ensure that the critical speeds are safely driven through can, so that an additional storage of the units can be omitted. 11) Universal joint according to claim 1), 2) or 3), characterized in that that the joint is used as an independent machine element. 12) shaft according to claim 5), 6), 7), 8) or 9), characterized by that the shaft shaft is used as an independent machine element. 13) cardan shaft according to one of the preceding claims, characterized in that that the wall thickness of the membrane is thinner than that of the shaft. 14) cardan shaft, in particular according to claim 4), characterized in that that serving as a mounting flange part (4) of the membrane against the as Joint acting part (2) is offset that even when using a straight one Counterflange (5) enough space (6) for the movements of the joint and for any Fastening elements of the counter flange remain. 15) cardan shaft according to one of the preceding claims, characterized in that that the membrane (2) at its inner diameter in the preferably as a hollow cylinder trained shaft shaft (1) passes. 16) cardan shaft according to one of claims 1) - 14), characterized in, that the diaphragm (2) merges at the outer diameter into the shaft shaft (1?) and that the shaft shaft is designed in particular according to claim 7). 17) cardan shaft according to one of the preceding claims, characterized in that that glass, carbon or aramid fibers are used to reinforce the plastic. 18) cardan shaft according to one of the preceding claims, characterized in that that a fiber mixture is used to reinforce the plastic. 19) Cardan shaft according to one of the preceding claims, characterized in that that the same fibers are used to reinforce the shaft shaft (1) how to strengthen the joint (2). 20) Cardan shaft according to one of the preceding claims, characterized in that that different to reinforce the plastic in the shaft shaft and in the joint Fibers or fiber mixtures are used. 21) cardan shaft according to one of the preceding claims, characterized in that that in the production a form is used, which from a tube or Solid body designed mandrel (11), for example made of metal or a self-separating one Plastic, with an outer diameter of 4 or corresponding to an outer shape the desired inside diameter or the inside contour of the desired shaft shaft (1), at the end or at both ends of which are detachable, disc-shaped or conical Elements (12), e.g. 3. by means of a centering (16), which have an approach (15) with a preferably rounded transition between the membrane and the shaft shaft and possibly the desired profiling (13) according to claim 3) and possibly one preferably offset from the .Membrane Blanschflache (14) for shaping the later Have shaft attachment (4) and preferably made of metal or a self-separating Made of plastic. 22) cardan shaft according to one of the preceding claims, in particular but claim 21), characterized in that a mold is used in the manufacture is, characterized in that the disc-shaped or conical elements (12) for the production of the possibly profiled joint membrane (2) and the shaped elements (14) separate parts for producing the fastening flanges (4) or elements are. 23) Cardan shaft according to one of the preceding claims, characterized in that that a mold is used for their production, characterized in that the Elements (12, 14), which form the shape of the membranes and possibly the flanges, to make it easier the demolding of the cured component by means of a, preferably integrated, The push-off device (16) can be pushed off the mandrel. 24) Cardan shaft according to one of the preceding claims, characterized in that as prefabricated, preferably metal force introduction elements during manufacture such as rings, washers or threaded pieces inserted into the mold and during production the shaft to be glued to it. 25) cardan shaft according to one of the preceding claims, characterized in that that in their manufacture a form is used which, deviating from claim 21), one or more removable cores (17), e.g. made of foam or a highly elastic one Material that contains or consists entirely of such a core to form an undercut To enable shaping, as it z.m. if not arranged at the outermost end of the shaft Membrane joints (7) or when pulled inward from the outer diameter of the membrane Fastening flanges (n ') or with diaphragm joints drawn inwards from the shaft diameter (2) can occur. 20) Cardan shaft according to one of the preceding claims, characterized in that that a process is used for their production which is characterized by the following features is characterized: a) r the production of the membrane disks utld the shaft shaft fiber fabrics, possibly mixed fabrics, are used. b) The pieces of tissue used for the membrane joints are inclusive of the possibly necessary hole cut beforehand and, e.g. when using a mold according to claim 21) - 2 #), positioned on the mandrel (11) before the end disks (12, 14) or removable cores (17) are attached so that no slots in the Cuts are necessary. c) For the production of the preferably cylindrical shaft shaft (2) becomes the grain direction of the fibers running approximately diagonally on the shaft through targeted warping of a # 00 / 9u0 ~ fabric or through the use of unidirectional The fabric is optimized for the intended use and the fabric is then wound up accordingly. d) If necessary, it may be required to run approximately longitudinally to the shaft axis Fibers are preferably applied by winding unidirectional fabric. e) The power transmission from the joint into the shaft shaft is through a corresponding overlap is ensured, preferably the individual Layers alternately overlapped. 27) cardan shaft according to one of the preceding claims, characterized in that that it is made in the filament winding process. 28) cardan shaft according to one of the preceding claims, characterized in that that a process is used for their production, characterized in that, around the individual fiber layers in the grooves (13) of the membrane molds (12, 14) and hold it there, preferably made of highly elastic material from the opposite side Material such as silicone rubber, preferably the shape of the profile adapted counterparts (20), radially slotted if necessary, by means of one or more Pressure plates (1ç) are pressed onto the mold in such a way that the fibers exactly match the mold contour must follow and excess arz is wiped out to the side. 29) propeller shaft according to one of the preceding claims, produced according to a method which is characterized in that, if necessary after removing the disc-shaped or conical shaped elements (12, 14) for possible end membranes (2, 4), by axial pressure on one of the shaft ends, preferably applied via a pressure piece (21) adapted to the shape of the shaft end (the latter in particular with a membrane at the end), a widening of the shaft shaft (1) over the effect of the transverse expansion is achieved and thus the demolding of the shaft (1) is facilitated by the mandrel (11), and since the mandrel acts as an abutment for this pressure is used so that the mushrooms can be pushed off the mandrel. 30) Cardan shaft according to one of the preceding claims, characterized in that that in their production for demolding the Wellenscraftes from the mandrel of the different The thermal expansion coefficient of the material of the shaft and the mandrel is used, in that demolding takes place at a different temperature than curing the wave.