AT520740B1 - gear - Google Patents

Abstract

The invention relates to a toothed wheel (1) comprising an inner and an outer ring element (2, 3), wherein the outer ring element (2) has an outer toothing (5) and the inner ring element (3) has a plurality of first projections (9) projecting radially outwards. and elastomeric elements (20) are arranged between the inner ring element (2) and the outer ring element (3). The second ring element (3) has a plurality of second projections (11) projecting radially inwards, between which recesses (13) are formed, into which project the first projections (9) of the first ring element (2), wherein in the circumferential direction (10 ) the first protrusions (9) are spaced apart from the second protrusions (11) to form gaps (18, 19), and in each gap (18, 19) an elastomeric element (20) is arranged which is not connected to either the inner or is connected to the outer ring element (2, 3), and the elastomer elements (20) in the unloaded state in the axial direction (8) are longer than the recesses (13), and in the axial direction (8) are biased, wherein the projections ( 9, 11) have a trapezoidal cross section and the elastomer elements (20) are cuboidal.

Description

Description: The invention relates to a gearwheel comprising a first, radially inner ring element, a second, radially outer ring element and optionally at least one cover element, the second, radially outer ring element having external teeth and the radially inner ring element having a plurality of radially outwardly projecting first projections and wherein elastomeric elements are arranged between the radially inner ring element and the radially outer ring element, and the gear wheel has an axial direction, a radial direction and a circumferential direction, the second, radially outer ring element having a plurality of radially inwardly projecting second projections, between them second projections recesses are formed, into which the first projections of the first, radially inner ring element protrude, the first projections being narrower in the circumferential direction, that is to say the recesses between the second projections, so that in the circumferential direction g the first projections are arranged on one side or on both sides to form gaps spaced from the second projections, an elastomer element being arranged in each gap, which is neither connected to the first, radially inner ring element nor to the second, radially outer ring element, and the Elastomer elements in the unloaded state are longer in the axial direction than the recesses between the second projections of the radially outer ring element, viewed in the same direction, and the elastomer elements are prestressed in the axial direction by compression in the axial direction.

To avoid vibration excitation in the transmission of torque by means of gears, it is known from the prior art to use elastically deformable elements. For example, AT 501 915 A4 describes a device for torsionally elastic torque transmission between a shaft and a gear wheel mounted on the shaft, forming a ring gear and a hub, with two coupling parts assigned to the shaft and the ring gear rotating test, the mutually protruding claws which are offset have, and arranged between the claws, elastomeric damping bodies, wherein the two coupling parts are supported only in the circumferential direction via the damping body and the sprocket is rigidly supported by the hub in the radial direction in relation to the shaft. Since the gap between the claws of the two coupling parts is filled with an elastomeric material, torsional vibrations occurring between the ring gear and the hub are damped by the elastomeric intermediate layer between the mutually opposite flanks of the interlocking claws. The relentless mounting of the ring gear in the radial direction avoids any additional vibrations that may occur, which can have a disadvantageous effect on the tooth engagement. However, this gear requires a relatively large amount of space.

[0003] DE 10 2009 058 378 A1 discloses a toothing arrangement with a first gearwheel and with a second gearwheel which meshes with the first gearwheel. The first gear comprises an inner ring with an axis of rotation (A); an outer ring, which is arranged coaxially to the axis of rotation (A) of the inner ring and has an external toothing in which the second gear engages with counter-toothing, the engagement between the first gear and the second gear taking place exclusively via the outer ring, at least one elastic element which is arranged between the inner ring and the outer ring, the outer ring being supported radially with respect to the inner ring via the at least one elastic element, and the outer toothing and counter toothing relative to one another in a load-free state in which no torque is transmitted between the first gear wheel and the second gear wheel are radially elastically biased or jammed. The disadvantage here is that the elastic element is subjected to great stress and the entire gear fails in the event of cracks in the elastic element.

Other gears of this type, in which a hub part is connected to a ring gear via an elastic element, for which purpose the elastic element is vulcanized are known from the publications AT 514 590 A4, AT 516 397 A4 and AT 514 570 A4.

/ 13

AT 520 740 B1 2019-07-15 Austrian

Patent Office WO 2013/175209 A1 describes a flexible coupling for transmitting a torque with concentric inner and outer coupling elements. The inner member has a plurality of spaced-apart first protrusions that extend toward the outer member. The outer member has a plurality of spaced apart second projections which extend inwardly of the inner member. The first and second protrusions define a plurality of pockets between them, an elastomeric element being arranged in each pocket.

Is a coupling element is known which has a radially inner and a radially outer component, projections are formed between and of the components. Between the projections there are recesses in which rubber elements are arranged.

[0007] DE 10 2005 016 558 A1 describes an electric tool comprising: a housing; a motor provided in the housing and having a drive shaft; a gear unit, which is mounted in the housing and is driven by the drive shaft; and a rotary shaft rotatably supported in the housing and driven by the gear unit, the gear unit comprising: an intermediate member that is force-connected to the rotary shaft at a predetermined power connection pressure, the predetermined power connection pressure allowing the rotary shaft and the intermediate member in Rotate with respect to each other when a load exceeding a predetermined load is applied between the rotating shaft and the intermediate member, the intermediate member having an abutting projection; and a gear driven by the drive shaft and provided concentrically with the rotary shaft and having a surrounding portion surrounding the intermediate member and provided with a convex portion, the peripheral portion drivingly connected to the intermediate member to rotate the rotary shaft, the abutment protrusion being engageable with the convex portion when the rotating shaft and the gear are rotated with respect to each other.

From DE 14 75 519 A1 a torque transmitter is known which has two concentric coupling members which have a number of plates or arms which extend essentially radially from the members and are arranged so that each plate is one Coupling member lies between two plates of the other coupling member so that a cell is formed between each pair of adjacent plates and parts of the concentric coupling members, and with a single non-metallic resilient coupling member in each cell, which is in one piece and has at least two arms and a connecting part, the Arms abut opposite cell walls and the connecting part is designed such that the arms are first bent by applying torque by bending relative to the connecting part such that the contact area between the arms and / or between the arms and the connecting part increases, as a result of which increasing Torque the arms and the connector are increasingly compressed, while the bend decreases.

From JP H04-54347 A a gear is known in which rubber elements are arranged between radial projections of a radially inner and a radially outer component.

[0010] DE 102 59 519 A1 describes a transmission with a drive gearwheel which is seated on a drive shaft and an output gearwheel which meshes with it and drives an output shaft, spring-elastic damping elements being arranged between the output gearwheel and the output shaft.

EP 1 396 420 A1 describes a vehicle with an engine and a gear change transmission that connects a drive device to a crankshaft of the engine, an input shaft of the gear change transmission being connected to one end of the crankshaft via a damping device, which is a torque transmission device, wherein a plurality of elastic parts are provided between radially extending surfaces of a drive side body and a driven side body, and wherein the input shaft and the crankshaft are arranged on a common axis of rotation.

2.13

AT 520 740 B1 2019-07-15 Austrian

Patent Office The present invention has for its object to provide an improved damped gear.

The object of the invention is achieved in the gear mentioned at the outset in that the first and two projections have an at least approximately trapezoidal cross section and the elastomer elements are at least approximately cuboid.

An advantage of the gear is that the elastomer elements in the event of damage, such as Cracks in the elastomer, the functionality is still given, and thus the gear has a higher reliability. Even if individual or all elastomer elements are completely eliminated, the functionality of the gear remains intact. Since the individual elastomer elements are only inserted into the gaps mentioned, the vulcanization process is also dispensed with, as a result of which the manufacture of the gearwheel can be simplified. In addition, the gear is relatively simple and can be easily adapted to different diameters, since the elastomer elements are not connected to one another, but rather are arranged as individual elements. In addition, a gearwheel can thus be made available that has low stresses or small expansions in the otherwise critical elastomer components.

The elastomer elements are viewed in the axial direction longer than the recesses between the second projections of the radially outer ring element, in the same direction. It is thus possible to insert the elastomer elements more easily into the gaps between the first and second projections of the first and second ring elements, in particular if they are made with a smaller width than the gaps viewed in the same direction.

This simpler usability of the elastomer elements can be supported if the elastomer elements have at least one outwardly curved side surface, and / or if the elastomer elements have a depression in at least one end face pointing in the axial direction.

The elastomer elements are prestressed in the axial direction. A relatively high stiffness of the gearwheel can thus be achieved, which can be adjusted via the degree of hardness of the elastomer used and the size of the axial preload. The greater length of the elastomer elements in the axial direction and / or their curved side surface and / or their recess in the end face have a supporting effect, since this not only makes the prestressing easier, but the gear stiffness can also be adjusted via the elastomer volume displaced during prestressing ,

Preferably, the prestressing of the elastomer elements with the cover element takes place when the gear is being assembled, since this means that no further components are required for the gear.

For better support of the cover element, the first, radially inner ring element in a further embodiment of the gear can have a ring web projecting in the axial direction. It is thus possible for the cover element to be connected exclusively to the second, radially outer ring element, as a result of which the assembly of the gearwheel can be simplified.

It can further be provided that edges of the elastomer elements are provided with a rounding, whereby the elastomer elements are subject to a reduced risk of damage during axial pretensioning. In addition, the insertion of the elastomer elements can also be made easier.

For a better understanding of the invention, this will be explained in more detail with reference to the following figures.

[0022] Each shows in a simplified, schematic representation:

Figure 1 is a gear in an exploded view and in an oblique view.

3.13

AT 520 740 B1 2019-07-15 Austrian

Patent Office [0024] Fig. 2 [0026] Fig. 4 [0027] Fig. 5 shows the two ring elements of the gear wheel according to Fig. 1 in the assembled state;

the two ring elements of the gear of Figure 1 in the assembled state and with inserted elastomer elements. an elastomer element in an oblique view;

1 in the assembled state and in an oblique view.

In the introduction, it should be noted that in the differently described embodiments, the same parts are provided with the same reference numerals or the same component names, and the disclosures contained in the entire description can be applied analogously to the same parts with the same reference numerals or the same component names. The location information selected in the description, e.g. above, below, to the side, etc., referring to the figure described and illustrated immediately, and if the position is changed, these are to be applied accordingly to the new position.

In Fig. 1, an embodiment of a gear 1 is shown. 2 to 3 each show parts of this gear 1.

The gear 1 comprises a first, radially inner ring element 2, a second, radially outer ring element 3 and a cover element 4. The first, radially inner ring element 2 can also be referred to as a hub part and the second, radially outer ring element 3 as a ring gear , since the first, radially inner ring element 2 serves to receive a shaft or the like, not shown, and the second, radially outer ring element 3 has external teeth 5. Via this external toothing 4, the gearwheel 1 can be in meshing engagement with another gearwheel, for example a gearwheel gear, in order to transmit torque.

The first, radially inner ring element 2 is arranged radially below the second, radially outer ring element 3, in particular viewed in a radial direction 6 entirely below the external toothing 5. Preferably, the first, radially inner ring element 2 is entirely within the second, arranged radially outer ring element 3, although a hub region 7 of the first, radially inner ring element 2 can be wider in an axial direction than the second, radially outer ring element 3.

The first, radially inner ring element 2 and / or the second, radially outer ring element 3 preferably consist of a metallic material, for example of a steel, preferably of a sintered material, for example a sintered steel. However, other metallic materials can also be used for the first, radially inner ring element 2 and / or the second, radially outer ring element 3, the first, radially inner ring element 2 and / or the second, radially outer ring element 3 also comprising at least two different metallic materials can exist. It is also conceivable that the first, radially inner ring element 2 and / or the second, radially outer ring element 3 consist of at least one polymeric plastic.

The first, radially inner ring element 2 has a plurality of first projections 9 projecting outward in the radial direction 6. These first projections 9 are arranged on the radially outer circumferential surface of the hub part 7, in particular connected to it in one piece. When viewed in the axial direction 8, the first projections 9 have an at least approximately trapezoidal cross section, in particular that of an isosceles trapezoid, the short base side being arranged on the hub part 7. These first projections 9 are preferably arranged in a circumferential direction 10 of the gear 1 evenly distributed over the circumference of the hub part 7.

Furthermore, the first, radially inner ring element 2 has a recess running in the axial direction 8, in particular a bore. This allows the first, radially inner ring element 2 on the shaft, not shown, or another element such as one

4.13

AT 520 740 B1 2019-07-15 Austrian

Patent Office

Unbalance element. The unbalance element can in turn have a recess, in particular a bore, for arrangement on a shaft.

The second, radially outer ring element 3 has a plurality of, in the radial direction 6 projecting second projections 11, which, in contrast to the first projections 9, are arranged not projecting outwards, but projecting inwards. The second projections 11 are arranged on a lower circumferential surface 12 of the second, radially outer ring element 3, in particular connected to it in one piece. When viewed in the axial direction 8, the second projections 11 likewise have an, at least approximately, trapezoidal cross section, in particular that of an isosceles trapezoid, the long base being arranged on the lateral surface 11. The second projections 11 thus taper in the radial direction 6 from the outside inwards, that is to say in the opposite direction to the first projections 9. Preferably, the second projections 11 are also uniformly distributed in the circumferential direction 10 of the gear 1 over the circumference of the lateral surface 12 ,

[0036] Preferably, the first protrusions 9 and the second protrusions 11 (rotated 180 ⁰⁾ have the same cross-sectional shape.

For the sake of completeness, it should be mentioned that the base sides of the trapezoidal cross section of the first and second projections 9, 11 are not straight, but curved, which is due to the round shape of the gear 1.

Between the second projections 11 10 recesses 13 are formed in the circumferential direction. Likewise, recesses 14 are formed between the first projections in the circumferential direction 10. The arrangement of the recesses 13, 14 is such that the first projections 9 are at least partially, in particular entirely, received in the recesses 13 between the second projections 11 and the second projections 11 in the recesses 14 between the first projections 9. as can be seen from, for example, FIG. 2. By “in its entirety” it is meant that the first projections 9 are slightly spaced from the lateral surface 12 and the second projections 11 from the hub part 7, so that the relative rotatability of the first ring element 2 to the second ring element 3 in the circumferential direction 10 is possible.

The first projections 9 are narrower in the circumferential direction 10, that is, they have a shorter length 15 (FIG. 2) than the recesses 13 in the circumferential direction 10. The length 15 is measured at the same radial height as the length of the recesses to take into account the widening cross section of the first projections.

Due to the narrower first projections 9 in the circumferential direction 10, the first projections 9 are spaced apart in the circumferential direction 10, in the axial direction 8 extending side surfaces 16, 17, whereby gaps 18, 19 are formed, as is best 2 can be seen. In addition to each first projection 9, a gap 18 and a gap 19 are formed in the circumferential direction 10, so that the gaps 18, 19 are formed on both sides of the first projections 9. In this embodiment variant of the gear wheel 1, the first projections 9 therefore do not rest on either of the two side surfaces 16, 17 of the second projections 11.

An elastomer element 20 is arranged in each of these gaps 18, 19, as can best be seen from FIG. 3. The elastomer elements 20 are thus arranged between the first, radially inner ring element 2 and the second, radially outer ring element 3. The elastomeric elements 20 are loosely inserted into the gaps 18, 19, i.e. that they are neither connected to one another nor to the first, radially inner ring element 2 and the second, radially outer ring element 3, that is to say in particular they are not glued on or vulcanized on.

Such an elastomer element 20 is shown in FIG. 4.

The elastomer element 20 consists at least partially of a rubber-elastic material, for example of an (X) NBR ((carboxylated) acrylonitrile butadiene rubber), HNBR (hydrogenated nitrile rubber), a silicone rubber (VMQ), NR ( Natural rubber), EPDM

5.13

AT 520 740 B1 2019-07-15 Austrian

Patent Office (ethylene-propylene-diene rubber), CR (chloroprene rubber), SBR (styrene-butadiene rubber) etc., whereby here again material mixtures can be used.

By "at least partially" it is meant that in the elastomer element 20 e.g. Stiffening elements, e.g. Fibers and / or threads, for example made of metal, plastic, natural fibers, etc., or rods, etc. can be incorporated in order to change or adjust their stiffness. The elastomer element 20 can also have regions made of rubber-elastic materials that differ from one another. However, the elastomer element 20 preferably consists exclusively of a rubber-elastic material.

The elastomer element 20 of this variant of the gear 1 is at least approximately cuboid. This shape is made possible by the described shape of the first and second projections 9, 11.

To simplify assembly of the elastomer elements 20, it can be provided that a further cover element 21 is arranged on the first, radially inner ring element 2 or preferably on the second, radially outer ring element 3 and is connected thereto, for example in a form-fitting and / or non-positive manner and / or cohesive. This further cover element 21 can also be formed in one piece with the first, radially inner ring element 2 or preferably on the second, radially outer ring element 3. The further cover element 21 covers the recesses 13 in the axial direction 8 on one side of the gear 1 at least partially, in particular entirely, so that the elastomer elements 20 can be placed on this further cover element 21 during assembly.

When all of the elastomeric element 20 is assembled, i.e. are inserted, they are at least partially, preferably entirely, covered on the second side in the axial direction 8 with the cover element 4, as shown in FIG. 5. The cover element 4 can be connected to the first, radially inner ring element 2. However, it is preferably connected to the second, radially outer ring element 3 according to one embodiment variant of the gearwheel 1. Depending on the application of the gear 1, the connection can be made releasably, for example with screws, or integrally, for example by welding.

In a simpler variant of the gear 1, only the gaps 18 or only the gaps 19 between the first and second projections 9, 11 can be formed. The elastomer elements 20 are therefore present on only one of the two side surfaces 16, 17 of the second projections 11. On the other hand, the first and second projections can be at least approximately in contact with one another. Although this embodiment variant is not preferred, it can nevertheless be used in applications in which the gearwheel 1 is only operated in one direction of rotation.

In the illustrated embodiment variant of the gearwheel, all elastomer elements 20, viewed in the circumferential direction 10, are of the same thickness. However, there is also the possibility that the elastomer elements 20 have different thicknesses in this direction. For example, every second elastomer element 20 can be made thinner than the remaining elastomer elements 20. It is therefore possible to use thicker elastomer elements 20 for one direction of rotation of the gearwheel 20 and thinner ones for the second direction of rotation of the gearwheel. Likewise, elastomer elements 20 of different hardness can be used in these two directions, for example hard in a first direction and, in comparison, softer in the second direction. In addition, an asymmetrical distribution of mutually different elastomer elements 20, for example elastomer elements 20 of different hardness, over the circumference of the gearwheel 1 is also possible in order to obtain a direction-dependent radial rigidity.

The gear 1 can, as stated above, have the first, radially inner ring element 2, the second, radially outer ring element 3, at least one connecting element and a plurality of elastomer element 20. The gear 1 can also consist only of these components.

It is provided that the elastomer elements 20 are longer than in the axial direction 8

13.6

AT 520 740 B1 2019-07-15 Austrian patent office viewed the gaps 18, 19 and thus the recesses 13 between the second projections 11 of the second, radially outer ring element 3 in the same direction. Among other things, it can be achieved in particular that the elastomer elements 20 are squeezed in the axial direction 8 and can thus be prestressed more easily in this direction. In other words, the elastomer element 20 can be prestressed by compression in the axial direction 8.

In order to support or simplify this compression of the elastomer elements 20, it can be provided according to a further embodiment variant of the gear wheel 1 that the elastomer elements 20 have at least one outwardly curved side surface 22, as can be seen in particular from FIG. 4. The side surface 22 is in particular convexly curved.

[0053] The curvature can be formed on the side surface 22 pointing in the axial direction 8. These two side surfaces 22 of the elastomer elements 20 are preferably curved, as shown in FIG. 4.

Alternatively or additionally, the other side surfaces and / or the bottom surface and / or the top surface of the elastomer elements 20 can also be curved.

Although the curvature of at least the side surface (s) 22 is preferred outwards, at least some of the outer surfaces of the elastomer elements 20 can be arched inwards. In particular, this curvature can be made concave.

According to a further embodiment of the gear, which is also shown in FIG. 4, the elastomer elements can have a recess 24 in at least one end face 23 pointing in the axial direction 8, in particular in both end faces 23 pointing in the axial direction 8. The compressibility of the elastomer elements 20 can thus also be influenced or simplified.

The end faces 23 correspond to the above-mentioned bottom surface and top surface of the elastomer elements 20.

As already stated, the elastomer elements 20 are preloaded in the gear 1 in the axial direction 8. The bias can be made accordingly. The prestressing of the elastomer elements 20 is preferably formed in the axial direction 8 when the gear wheel 1 is assembled by fastening the cover element 4.

According to a further embodiment variant of the gear 1, it can be provided that the first, radially inner ring element 2 on the hub part 7 has a ring web 25 projecting in the axial direction, as can be seen in particular from FIG. 1. The ring web 25 is preferably placed in such a way that the cover element 4 can be supported on the gearwheel 1 in the radial direction 6 in the assembled state thereof. Alternatively or additionally, the cover element 4 can be supported via the first and / or second projections 9, 11.

The annular web 25 preferably has a height in the axial direction 8 which corresponds to the thickness of the cover element 4 in this direction.

Instead of the ring web 25, other geometric shapes, such as a square or a polygon.

It can further be provided that edges of the elastomer elements 20 are provided with a rounding, as can be seen in particular from FIG. 4.

Apart from the at least one curvature and / or the at least one depression 24, the shape of the elastomer elements 20 essentially depends on the shape of the gaps 18, 19. However, the shape of the elastomer elements 20 can also be predetermined, for example if the Elastomer elements 20 should have a certain mass, and the gaps 18, 19 are adapted to this shape.

Furthermore, the (cross-sectional) shape of the first projections 9 and / or the

7.13

AT 520 740 B1 2019-07-15 Austrian

Patent Office second projections 11 influences the displacement of the elastomer elements 20 and thus the behavior of the gear 1 per se can be changed or adjusted.

It can also be provided that a radial play is provided between the ring elements 2 and possibly including the cover element 4 and the ring element 3. The radial play can be selected to be different in size depending on the requirements.

In the above-mentioned embodiment variants of the gear 1, instead of the at least one cover element 4, a shoulder or a radial projection on the ring element 3 below the external toothing 5 between the projections 11 and / or between the first projections 9 or in the circumferential direction 10 extending projections on the first and / or second projections 9, 11 may be arranged.

For the sake of order, it should finally be pointed out that, for a better understanding of the structure, the gear 1 is not necessarily drawn to scale.

8.13

AT 520 740 B1 2019-07-15 Austrian

Patent Office

LIST OF REFERENCE NUMBERS

gear

ring element

ring element

cover

external teeth

radial direction

hub part

axially

head Start

circumferentially

head Start

lateral surface

recess

recess

length

side surface

side surface

gap

gap

elastomer element

cover

side surface

face

deepening

ring land

9/13

AT 520 740 B1 2019-07-15 Austrian

Patent Office

Claims (6)

claims 1. gear (1) comprising a first, radially inner ring element (2), a second, radially outer ring element (3) and optionally at least one cover element (4), the second, radially outer ring element (2) having external teeth (5) and the radially inner ring element (2) has a plurality of radially outwardly projecting first projections (9), and wherein elastomer elements (20) are arranged between the first, radially inner ring element (2) and the second, radially outer ring element (3), and the gearwheel (1) has an axial direction (8), a radial direction (6) and a circumferential direction (10), the second, radially outer ring element (3) having a plurality of radially inwardly projecting second projections (11), between these second Projections (11) are formed in recesses (13) into which the first projections (9) of the first, radially inner ring element (2) protrude, the first projections (9) being narrower in the circumferential direction (10), that is to say the outside Trimmings (13) between the second projections (11), so that in the circumferential direction (10) the first projections (9) on one side or on both sides with gaps (18, 19) are spaced from the second projections (11), wherein in Each gap (18, 19) is arranged an elastomer element (20) which is neither connected to the first, radially inner ring element (2) nor to the second, radially outer ring element (3), and the elastomer elements (20) in the unloaded state in the axial direction (8) are longer than the recesses (13) between the second projections (11) of the radially outer ring element (3), viewed in the same direction, and the elastomer elements (20) in the axial direction (8) by compression in the Are biased axially, characterized in that the first and second projections (9, 11) have an at least approximately trapezoidal cross-section and the elastomer elements (20) are at least approximately cuboid t are. 2. Gear (1) according to claim 1, characterized in that the elastomer elements (20) have at least one outwardly curved side surface (22). 3. Gear wheel (1) according to claim 1 or 2, characterized in that the elastomer elements (20) have a recess (24) in at least one end face (23) pointing in the axial direction (8). 4. Gear (1) according to one of claims 1 to 3, characterized in that the bias with the cover element (4) is made. 5. Gear (1) according to one of claims 1 to 4, characterized in that the first, radially inner ring element (2) has a ring web (25) projecting in the axial direction (8). 6. gear (1) according to any one of claims 1 to 5, characterized in that edges of the elastomer elements (20) are provided with a curve.