Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16H—GEARING
  • F16H55/00—Elements with teeth or friction surfaces for conveying motion; Worms, pulleys or sheaves for gearing mechanisms
  • F16H55/32—Friction members
  • F16H55/52—Pulleys or friction discs of adjustable construction
  • F16H55/54—Pulleys or friction discs of adjustable construction of which the bearing parts are radially adjustable

Definitions

• the invention relates to a gearwheel for a positive traction device with a variable number of teeth, with toothed members lying against an axial-radial adjusting device and forming a ring gear.
• Such a gear is e.g. known from DE 41 11 195 AI.
• the gearwheel is formed by a drive chain that produces a ring gear, which can be changed by changing the length of the pitch circle diameter by feeding and removing individual links via an auxiliary gearwheel. The individual removed links are stored in a memory inside the gear.
• the axial-radial adjustment device is designed as a pair of cones in which the two cones are axially adjustable relative to one another.
• similar devices are known from DE-PS 23 63 316, DE-PS 9 26 948, DE 82 02 012 Ul and US 1,305,526.
• the object of the invention is to make the gear simpler and smaller.
• the toothed members are formed by insert members and at least one switching member, the teeth of the toothed members being permanently in the meshing diameter of the gear and the tooth of the at least one switching member with constant division of the gear between an meshing diameter and one outside of the engagement diameter stable Location is switchable.
• the teeth are formed by a plurality of insert members and, as a rule, by a plurality of switching members.
• the insert members are designed such that the teeth are constantly arranged in the engagement diameter, that is to say they are in engagement with this traction means in a chain encompassing the gearwheel.
• the teeth of the switching elements can be switched back and forth between two layers. In one position they are also in the engagement diameter and can engage the chain, whereas the teeth in the second position are outside the engagement diameter. Since the pitch of the gear always remains constant, the teeth of the toothed members move towards one another when the tooth of an intermediate switching member is removed from the engagement diameter.
• the axial-radial adjustment device can also be designed as a pair of cones. However, other embodiments are also conceivable, such as adjustable spherical elements. It is important that the axial adjustment movement of the support device is converted into a radial movement of the insert members.
• the stable position avoids intermediate positions in which the tooth of the switching element lies only partially, ie not completely, in the engagement diameter and assumes a position, for example during operation of the gearwheel, in which it interferes with the rotating one Traction means, which a chain, a toothed belt, a ball cord or the like. can be intervenes.
• the gearwheel is also suitable for small motors or small gearboxes, e.g. can be used on bicycles.
• the insert members are in particular frictionally attached to the cones and are supported. In this way, overload protection is achieved, since the insert members slip on the cones when the maximum transmittable torque is exceeded, and damage to the entire transmission can thereby be prevented.
• the limit torque can be set to a desired value by means of corresponding covering surfaces and / or a change in contact pressure and / or lubricant either on the contact surfaces of the insert members on the cones or on the surfaces of the cones.
• One of the insert members is positively connected to at least one of the cones. In this way, losses resulting from slippage can be avoided and, in particular, relatively high torques can also be transmitted with small gears.
• a switching element is arranged between each insert element and is held by the latter both in the radial and in the circumferential direction. This arrangement does not require any additional elements for fixing the switching elements.
• the insert links and the switching links form an endless link chain that extends over the two cones and is supported on the cone surfaces with corresponding support surfaces of the insert links.
• the tooth of the switching element lying outside the engagement diameter preferably lies radially within the engagement diameter. This position of the tooth, which represents a stable position, is achieved by pulling it radially inwards. In this way, it is led out of the engagement diameter, so that it is no longer able to attack the traction device.
• the tooth of the switching element lying outside the engagement diameter is pivoted in the direction of an adjacent insert element.
• the tooth is also displaced radially inward, but additionally pivoted through a certain angle ⁇
• the tooth is pivoted exclusively, whereby the pivoting movement likewise brings it out of the engagement diameter and into a position in which it cannot act on the traction means.
• relatively high teeth can be switched in a simple manner, without space problems occurring inside the gearwheel. If the tooth of the switching element is no longer in the engagement diameter, the distance between the two insert elements flanking the switching element can be reduced until they are again divided. In this way, the total number of teeth of the gearwheel is reduced by the tooth pivoted out of the engagement diameter.
• a stable position of the successive insert elements, regardless of whether they are connected directly or indirectly via a switching element, is created by means of a common stop, by means of which they lie against one another.
• the forces from one insert member can be applied via this stop can be transferred to the other directly when the switching element assumes a position in which its tooth lies outside the engagement diameter. In this way, the switching elements are protected since they are not involved in the transmission of the torque.
• the stops can be used to exactly maintain the spacing. Furthermore, the stops ensure that the insert members are aligned with each other.
• the insert members rest on the cones via positive guidance means.
• This positive guidance means ensures that the insert members always lie against them regardless of the spacing of the two cones, it being possible to dispense with pressing forces on the spring means exerting the insert members.
• the positive guidance means also ensures that the insert members always lie against the conical surfaces.
• the positive guide means is designed as a conical groove which receives the guide sections of the insert members.
• the guide sections of the insert members engage in this conical groove and hold the insert members in place. "If the cones are moved towards or away from each other, the guide sections slide in the conical groove, so that the insert members slide along the surface line along the surface of the cone.
• the guide sections are designed as rods which are arranged on the insert members and run in the direction of the generatrix of the cones.
• the insert members are slidably guided on the bars. This has the advantage that the grooves need only be made so large that they are the rods of the Can record lengthways along a generatrix.
• the rods are also guided in the conical grooves in the circumferential direction so that they can be adapted to the different distances between the individual insert members.
• the insert members move along the rods and are held by them on the cone surface of the cones.
• the insert members are subjected to a prestressing force, e.g. one or more springs or the like, rest on the cones.
• a prestressing force e.g. one or more springs or the like
• At least one of the cones is axially resiliently mounted on an adjusting device, in particular under a prestressing force.
• the distance between the two cones is adjusted or adjusted via the adjusting device, at least one of the cones being resiliently mounted such that it only follows the adjusting force when one of the switching elements changes from its one stable position to the other stable position. In this way, it is additionally avoided that the switching elements assume intermediate positions.
• Figure 1 is a schematic diagram of a portion of the gear according to the invention with two Memory joint units, wherein the left memory joint unit is shown in the folded state and the right memory joint unit is shown in the expanded state;
• Figure 2 is a schematic diagram according to Figure 1, with additional bias and end position springs are shown;
• FIG. 3 is a diagram showing the tractive force curve between the folded and unfolded state of a storage joint unit
• Figure 4 shows a section through a section of a
• Embodiment of the invention with two memory joint units, the left memory joint unit being folded together and the right memory joint unit being unfolded;
• FIG. 5 shows basic sketches of other embodiments of the gearwheel according to the invention, wherein two storage joint units are shown in each case;
• Figure 1 shows a schematic diagram of two
• Each storage joint unit 1 or 2 in the folded or in the unfolded position.
• Each storage joint unit 1 or 2 has at least two insert members 3 and 4 or 4 and 5, each insert member having a tooth 6 which in the current engagement diameter 7 of the gear.
• Switching elements 8 and 9 are provided between the insert members 3 to 5, the switching element 8 being shown in the expanded state and the switching element 9 being shown in the folded state.
• Each switching element 8 or 9 has two folding elements 10 and 11 which are connected to one another in the joint 12. Furthermore, the folding element 10 with the insert member 3 in the joint 13 and the folding element 11 with the insert member 4 in the joint 14 is pivotally fixed. The joints 12 to 14 allow a limited pivoting movement of the folding elements 10 and 11 on the insert members 3 and 4 or 4 and 5.
• the folding elements 10 and 11 are also provided with intermediate members 20 which are arranged on the joint 12.
• Each intermediate link is provided with stops 15 and 16.
• stops 17 and 18 are provided on each folding element 10 or 11, wherein in the opened position, as shown in the case of the spear joint unit 2, the stops 18 of the folding elements 10 and 11 lie on the stops 16 of the intermediate members 20 and a further opening of the Folding elements 10 or a further pivoting of the folding elements 10 and 11 around the joint 12 is prevented.
• FIG. 1 only the stop 16 and the stop 18 for the folding element 11 are shown in the storage joint unit 2.
• a corresponding stop is provided for the folding element 10.
• the two folding elements 10 and 11 are folded together and the stop 17 of the folding element 11 lies against the stop 15 of the intermediate member 20. Accordingly, the folding element 10 bears against the intermediate member 20 with its stop.
• the radial distance of the joint 12 from the engagement diameter 7 is increased and thereby the intermediate member 20, on which the tooth 21, which corresponds to the tooth 19, is displaced radially inward from the engagement diameter 7.
• the joints 13 and 14 are also brought so close to each other that they overlap. In this position, in which the storage joint unit 1 is shown, the two teeth 6 of the insert members 4 and 5 have the pitch.
• the tooth 21 of the intermediate member 20 is still arranged between the two teeth 6 of the insert members 4 and 5, but lies radially within the engagement diameter 7 and therefore does not contribute to the transmission of force or torque.
• FIG. 2 shows a representation corresponding to FIG. 1, the two storage joint units 1 and 2 additionally being provided with a biasing spring 22 and an end position spring 23, respectively.
• the biasing spring 22 is designed as a leg spring and extends around the joint 12 of the intermediate member 20.
• the two legs 24 and 25 act in this way on the folding elements 10 and 11 that these, as shown in the storage joint unit 1, are compressed.
• the bias spring 22 thus always causes a reduction in the diameter of the gear.
• the intermediate member 20 has two edge recesses 26 and 27, each of which extends over part of the circumference of the intermediate member 20.
• the ends of the recesses 26 and 27 represent the end positions for the two folding elements 10 and 11.
• the end position spring 23 runs in the recesses 26 and 27 and has an essentially C-shaped profile.
• the ends of the end position spring 23 are undercut by the legs 24 and 25 of the biasing spring 22 and in a direction which corresponds to the folded position of the two folding elements 10 and 11.
• the folding elements 10 and 11 are always kept in the folded state. If the folding elements 10 and 11 are to assume a position as is reproduced by the storage joint unit 2, then a force must be applied against the biasing force of the biasing spring 22.
• the force of the end position spring 23 counteracts the pretensioning force of the pretensioning spring 22 when the folding elements 10 and 11 are unfolded, since the two ends of the end position spring 23 compress the legs 24 and 25.
• a qualitative force curve F is achieved from the combination of the forces of the two springs 22 and 23, as shown in the diagram in FIG.
• the ordinate represents the combined tensile force F and the abscissa the opening path A.
• the force runs between the folded position Azus and the unfolded position Aaus not linear, but S-shaped.
• the force F decreases relatively quickly both in the beginning and in the end area, whereas it only decreases slightly in the middle area. This course of forces enables the switching element 8 or 9 to adopt its end positions as quickly as possible and to avoid intermediate positions.
• FIG. 4 An exemplary embodiment is shown in FIG. 4, in which the memory joint unit 1 shown on the left is shown in the folded-in state and the memory joint unit 2 shown on the right in the opened-out state.
• the switching element 8 or 9 has four folding elements 28 to 31.
• the two folding elements 28 and 30 are connected to the insert member 4 via the joint 14 and the two folding elements 29 and 31 are connected to the insert member 3 via the joint 13.
• the folding elements 28 and 29 are articulated to one another via a joint 32 and the two folding elements 30 and 31 via the joint 12.
• the tooth 19 is fixed rigidly on the folding element 30.
• each of the teeth 6 of the insert members 3 to 5 has a round recess 33 on the side facing the folding element 30 and a recess 34 corresponding to the tooth contour on the other side.
• the tooth 21, which corresponds to the tooth 19 is received by the two adjacent teeth 6 of the insert members 4 and 5 when the switching member 9 is folded.
• the tooth base engages in the recess 33 and the tooth head in the recess 34.
• the tooth 21 is not only moved radially inwards out of the engagement diameter 7, but also undergoes a pivoting movement.
• This embodiment has the advantage that the switching elements 8 and 9 in moving from their unfolded to their folded position no additional space in the Need inside the gear.
• the joint 32 moves radially outwards and the joint 12 around the joint 14 in the clockwise direction.
• the end position spring 23 which acts on the two folding elements 28 and 29 is also tensioned.
• the end position spring 23 is fixed on humps 35. It can also be seen from FIG. 4 that the points of application of the end position spring 23 on the cusps 35 are above the joint 32 when the switching element 8 assumes its unfolded position and are located below the joint 32 on the switching element 9. As a result, stable end positions are achieved.
• a preload spring as in the examples in FIGS. 1 and 2 is not required in this exemplary embodiment in FIG. 4, since the insert members 3 to 5 are positively guided.
• the insert members 3 to 5 have guide sections designed as rods 36, on which they can be displaced linearly in the direction of the double arrow 37.
• FIG. 5a schematically shows the exemplary embodiment of FIGS. 1 and 2, but the intermediate member 20 has been omitted.
• the tooth 19 or 21 is in this case attached to the folding element 11, as is shown schematically by the arm 38.
• FIG. 5b shows the exemplary embodiment of FIG. 4, in principle, where the switching element 8 or 9 is constructed from four folding elements 28 to 31.
• the direction of the force F of the end position spring 23 is also clearly shown here.
• the force F acts on the two cusps 35, the two cusps 35 being located above the joint 32.
• the switching element In the storage unit shown on the left, the switching element is shown in the folded position, in which the two cusps 35, on which the force F of the end position spring 23 acts, lie below the joint 32.
• This position also represents a stable position in which the joint 14 is supported on a stop 40 and lies coaxially with the joint 13. In this position of the switching element, the tooth 21 is pivoted out of the engagement diameter. In the folded position of the switching element, the joint 14 bears against the stop 40, which is provided on the insert element 4.
• a spring 52 acts on the two folding elements 10 and 11.
• the folding elements 10 and 11 are provided with curved areas 53 and 54, which are located in the area of the joint 12. If the spring 52 is moved by a piston-cylinder unit 55 or another drive along the curved region 53, 54, it assumes one of the rest positions shown in FIG. 5c and holds the two folding elements 10 and 11 in the respective position.
• This arrangement has the advantage that the folding elements 10 and 11 assume defined positions and are held there, the adjustment forces being able to be applied at any time. The switching process always takes place when the links are out of engagement with the cones 42 and 43 (FIG. 6).
• direct actuators are also conceivable.
• FIG. 5d shows an embodiment in which the two joints 13 and 14 are connected to one another via a link 41. If the two joints 13 and 14 are moved towards one another, they move in the link 41, which moves the tooth 19 out of the engagement diameter, as is shown on the left in FIG. 5d is reproduced. The end position is reached when the joint 14 lies on the stop 40 of the insert member 4.
• FIG. 6 shows in principle embodiments of positive guides of the insert members, so that the biasing spring 22, as shown in Figure 4, can be omitted.
• Figure 6a shows schematically the two cones
• FIG. 6b shows a corresponding representation in the case of inner cones, which are advantageously used for snow-running gearwheels. Corresponding exemplary embodiments are shown in FIGS. 6c to 6f both for the inner cone and for the outer cone.
• FIG. 6g shows in principle the embodiment of FIG. 4, in which the positive guidance is realized via guide sections designed as rods 36. These rods 36 are also arranged in conical grooves 44 and 45 and can be moved in the circumferential direction. However, the rods 36 are fixed in the direction of the surface line, ie in the direction of the arrow 49. The insert members 3 to 5 run on the rods 36 in corresponding guides 50.
• This embodiment has the advantage that no additional space has to be created for accommodating the guide sections, since the insert members 3 to 5 run on the rods 36 with their guides 50.
• FIG. 6g schematically shows the compliant one Bearing of one of the cones, namely the cone 43 via a spring element 51. Via this spring element 51, the position of the cone 43 is automatically adjusted in such a way that the insert members 3 to 5 and the switching elements assume defined positions due to the division, in particular intermediate layers are avoided .
• the circuit of the gear according to the invention can e.g. by adjusting the distance between the two cones 42 and 43, which can be initiated via suitable adjusting elements.
• the adjustment elements advantageously engage eccentrically on one or both cones 42 and 43 and move them in the axial direction with respect to the other cone.
• the moving cone tilts slightly, which means that a defined switching point for the switching elements is created in the area where the adjusting element acts.
• the elasticity of the device and on the other hand the bearing play is used.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Transmissions By Endless Flexible Members (AREA)
• Gears, Cams (AREA)

Applications Claiming Priority (3)

Publications (1)

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ID=6464334

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Family Cites Families (7)

• 1992
  • 1992-07-29 DE DE19924224972 patent/DE4224972C1/de not_active Expired - Fee Related
• 1993
  • 1993-07-15 WO PCT/EP1993/001855 patent/WO1994003741A1/de not_active Application Discontinuation
  • 1993-07-15 EP EP93915915A patent/EP0651866A1/de not_active Ceased

Non-Patent Citations (1)

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