WO2018167063A1

WO2018167063A1 - Machine part, assembly and use of a machine part for forming an assembly

Info

Publication number: WO2018167063A1
Application number: PCT/EP2018/056246
Authority: WO
Inventors: Philipp Guth; Julian Popp; Matthias Deckert
Original assignee: Wittenstein Se
Priority date: 2017-03-15
Filing date: 2018-03-13
Publication date: 2018-09-20
Also published as: DE102017105558A1; TW201837325A

Abstract

The invention relates to a machine part (1) with a first housing (3), wherein the first housing (3) has an end-side first housing toothing (5), configured for coupling to an end-side second housing toothing (105) of a second housing (103) of a second machine part (100), wherein the first end-side housing toothing (5) is of self-locking design.

Description

MACHINE PART, ASSEMBLY AND USE OF A MACHINE PART FOR FORMING

AN ASSEMBLY

Field of the invention

The invention relates to a machine part with a housing, to an assembly of two machine parts, and to the use of two machine parts for forming an assembly.

Prior art

Machine parts which can be coupled to a second machine part are known from the prior art. Two machine parts, such as, for example, an engine housing and a gearbox housing, are often connected via solid flanges or adapter plates and secured by numerous screw connections.

The prior art frequently results in a large and complicated design which can be complicated to assemble.

Disclosure of the invention

It is an object of the invention to at least partially solve the problems from the prior art. In particular, it is an object of the invention to specify machine parts which are to be rapidly coupled without tools as far as possible. The intention is to have little susceptibility to error during the assembly.

The object is achieved with a machine part according to claim 1, and with a further machine part and use according to the further independent claims.

One aspect of the invention relates to a machine part with a first housing, wherein the first housing has an end- side first housing toothing, configured for coupling to an end-side second housing toothing of a second housing of a second machine part, wherein the first end-side housing toothing is of self-locking design. A toothing is referred to herein as self-locking if it is self-locking in engagement with a further toothing which is identical or mirror-inverted to the toothing.

A further aspect relates to a machine part with a first housing, wherein the first housing has an end-side first housing toothing, configured for coupling to an end-side second housing toothing of a second housing of a second machine part, wherein the machine part comprises a first shaft with an end-side shaft toothing. In the term "shaft toothing", the "shaft" part of the term refers to the circumstance of being a toothing arranged on the end side of a shaft. The shaft toothing can be a groove toothing, spline toothing, Hirth toothing or another toothing.

A further aspect relates to an assembly consisting of a machine part in one of the typical embodiments described herein with a second machine part, with a second housing having a second housing toothing matching the first housing toothing. Typical second end-side housing toothings are formed identically or in a mirror-inverted manner to the first housing toothing.

A further aspect of the invention relates to the use of a machine part in one of the typical machine-part embodiments described herein for forming an assembly according to one of the typical assembly embodiments described herein.

Embodiments of the invention relate in particular to machine parts with a first housing with an end-side first housing toothing. The first housing can be, for example, an engine housing with an engine accommodated therein, or a gearbox housing with a gearbox accommodated therein. A gearbox housing customarily has a drive side and an output side. The end-side first housing toothing can be formed, for example, on the drive side for coupling to an engine. For example, the end-side first housing toothing can be formed on the output side for coupling to a working machine. The first housing can be of single-part or else multi-part design. For example, but not limited thereto, an engine housing or a gearbox housing can have a plurality of parts connected in an interlocking manner. An engine housing or a gearbox housing can have a plurality of parts connected in an integrally bonded manner, such as, for example, parts connected by welding methods.

A second machine part, for forming an assembly, is typically designed analogously to one of the embodiments, described herein, of the machine part.

The end side is typically a side which is perpendicular to the longitudinal axis of the housing. The end side refers to that side of the first housing at which a second end-side housing toothing of a second housing can be brought into engagement with the first end-side housing toothing of the first housing. For the term "on the end side", the definitions described herein for "end side" apply analogously. Typically, the first housing toothing is self- locking upon engagement with the second housing toothing, or is of self-locking design. The self-locking produces a resistance, which is caused by static friction, against axial displacement of the toothing during transmission of a torque. In typical embodiments, the machine part comprises a first shaft. The first shaft typically comprises an end-side shaft toothing. The first shaft is customarily mounted in the first housing. In typical embodiments, the shaft toothing is of self-locking design. In typical embodiments, the shaft toothing can be designed, for example, as a groove toothing, spline toothing or as a Hirth toothing. For coupling to a second shaft, the shaft toothing is typically configured with a second shaft toothing.

In particular, the shaft toothing can be self-locking. During the transmission of torque between the first shaft and the second shaft, axial forces on said shafts of the machine parts can be minimized or prevented. The transmission of the torque typically takes place at least in a substantially interlocking manner. The first shaft can be driven, for example, via an engine. The second shaft can, for example, be a gearbox shaft which absorbs a torque of the first shaft. During the transmission of counter-torques between the first housing and the second housing, axial forces are likewise minimized by the self-locking of the housing toothing.

In typical embodiments of the invention, the first end- side housing toothing has a flank angle of at most 20° or at most 15° or at most 12° or at most 9°. The flank angle is typically at least 1° or at least 2°. In typical embodiments, the flank angle is at least 5° or at least 7° or at least 10°. Typical construction materials for the housing toothings are, for example, steel with a static coefficient of friction of approximately 0.2, or plastic with a static coefficient of friction of approximately 0.15. The flank angle is selected here in such a manner that it acts in a self-locking manner.

Typical embodiments typically have a first jump in diameter on the outer circumference of the first housing toothing. Customarily, at the first jump in diameter, an outer diameter of the first housing toothing is larger in the direction of the second machine part of an assembly of the first machine part with the second machine part. The outer diameter becomes larger, for example, in the direction of the end side of the first housing toothing comprising the first jump in diameter. The first jump in diameter is typically designed as part of a groove which is embedded in the housing toothing .

The groove is typically formed by the first jump in diameter and an opposite jump in diameter which is opposite to the first jump in diameter. The opposite jump in diameter is customarily formed on the axially opposite side of the first jump in diameter. The groove typically runs along the outer circumference of the housing, for example in the region of the respective housing toothing. In further exemplary embodiments, a groove is arranged on an inner side of the teeth of the housing toothing. Typical teeth as part of the housing toothing have, on their outer circumference, a groove which is oriented in the circulating direction. A groove permits the accommodating of a securing element, wherein, in typical embodiments, it is even possible merely to provide a jump in diameter for axially holding a securing element. In further embodiments, the groove typically runs along the inner circumference of the housing.

The first jump in diameter typically has a wall which is inclined in relation to a cross-sectional plane of the machine part. The cross-sectional plane here is a section which is perpendicular to the axis of rotation of the shaft. The inclined wall can be inclined, for example, by at least 1° or at least 5°. The inclined wall is inclined, for example, by at most 20° or at most 15°, for example in order to achieve self-locking. In typical embodiments, the opposite jump in diameter can also have an inclined wall.

Typical machine parts of the invention comprise a securing element which, in a closed state, lies against the first jump in diameter. The securing element can be, for example, a securing ring, for example an open or closed securing ring, a snap ring, a round wire snap ring, or a securing element consisting of a plurality of elements. In typical embodiments, the securing element has a variable circumference, and therefore it can be widened, for example. The securing element is, for example, composed of an elastically deformable material, such as, for example, of a metal with an elastic range of extension, or of an elastic plastic. The securing element can also be designed, for example, as a rubber ring. In typical embodiments, the inclined wall of the jump in diameter is inclined in such a manner that the wall acts in a self-locking manner in relation to the securing element escaping radially.

In typical embodiments, the machine part has a retainer ring. The retainer ring can be designed, for example, as a sleeve or cap nut . Typical retainer rings are displaceable axially along the housing.

In further embodiments, the first housing has an external thread in which the retainer ring engages. This permits an axial movement or securing of the retainer ring by rotation of the retainer ring.

The retainer ring in a closed state typically engages over the first jump in diameter. The retainer ring can thus, for example, secure the securing element against radial or axial displacement. For example, the retainer ring pushes the securing element onto the first jump in diameter. In typical embodiments, the retainer ring is prestressed axially in relation to the housing, in particular in the direction of the second machine element, by means of a spring element. The spring element can be designed, for example, as a corrugated washer. In typical embodiments, the spring element presses the retainer ring onto the securing element. The spring element prestresses the retainer ring in the direction of the end side. In typical embodiments, the retainer ring is prestressed against the securing element via the spring element.

The first shaft of typical embodiments has a compensating element for compensating for a radial or axial offset or an angular offset of the first shaft relative to a second shaft which is to be connected. In typical embodiments, a compensating element is attached to the first shaft. The compensating element can be designed, for example, as a bellows coupling, metal bellows, or as a corrugated pipe coupling, or as a similar compensating element which compensates for a radial or axial offset of a connection of two shafts or two housings. The compensating element can compensate, for example, for inaccuracies, for example those due to manufacturing tolerances, thermal expansion or contraction. In a typical assembly according to the embodiments, the compensating element can increase the contact pressure between the machine parts or can compensate for an axial prestress. In further typical embodiments, the second shaft has a compensating element. In typical embodiments, a compensating element is attached to the first or second housing to compensate for a radial or axial offset of the two machine elements with respect to each other.

Inlet surfaces are typically in each case provided on the end surfaces of at least some of the teeth of the first housing toothing. The inlet surfaces which may also be referred to as inlet slopes are customarily at an axially outer end of the teeth. This creates a toothing which slides together and can be connected in a simple manner. For example, the tooth tips can have inlet slopes. A slope of the tooth tips refers to a surface or part of a surface that is not perpendicular to the longitudinal axis of the shaft. This can be, for example, an individual slope, or two slopes with a geometry tapering at least substantially in the shape of a roof, but also a slope of a spherical or semicircular rounding on the end surfaces. The longitudinal axis of the shaft refers to an axis which is oriented in the direction of the axis of rotation of the shaft or in the direction of a rotationally symmetrical axis of the housing.

Typical inlet surfaces are inclined by at least 10° or at least 20° in relation to a cross-sectional plane. The cross-sectional plane is a plane which is perpendicular to the longitudinal axis. The angle of inclination of typical inlet surfaces is at most 30°. The inlet surfaces here are typically designed such that they guide the teeth of a first housing toothing into the tooth gaps of a second housing toothing. The inlet surfaces assist the orientation of a second housing toothing into a position which is suitable for the coupling and from which, for example, a closed state can take place.

In typical embodiments of the invention, the groove is arranged in such a manner that, in a closed state of a connection to a second housing with a second housing toothing and second groove, an axial offset occurs between the first groove and the second groove.

In typical embodiments, the securing element is prestressed by the axial offset in order to brace the two housing toothing against opening of the connection.

In typical embodiments of the assembly, the end-side second housing toothing is designed analogously to the typical embodiments, described herein, of the end-side first housing toothing. In typical embodiments of the assembly, the flanks of the first and the second housing toothing are at least partially flatly adjacent in a closed state. The closed state is an at least partially interlocking connection. In typical embodiments, the closed state is a prestressed interlocking connect ion .

A typical embodiment of the assembly has a first groove of the first housing toothing and a second groove of the second housing toothing. As a result, a securing element which is inserted into the grooves can axially fix the first and the second machine part. The first groove is typically designed in such a manner that, when the toothings engage in the closed state, the grooves have an axial offset with respect to each other. In typical embodiments, the sign of the axial offset can be chosen such that the securing element prestresses the housings in relation to each other in the direction of the closed state. The axial offset in typical embodiments is at least 0.05 mm, typically at least 0.1 mm, typically at most 1 mm or at most 0.5 mm. The prestressing is achieved, for example, by the securing element lying alternately against the respective walls of the grooves or the respective jump in diameter of the two toothings.

Typical embodiments have the advantages that a machine part can be coupled to a second machine part as far as possible without a tool. As a result, a connection of two machine parts is achieved, as simply as possible. The assembly can take place without additional axial screw connections. A further advantage in typical embodiments is as simple a release of the assembly as possible. In typical embodiments, the connection of the assembly is self- centering. Advantages of the typical embodiments are a low susceptibility to error during the connection of the assembly. The slightly rotating masses of the typical embodiments have the advantage of a low mass inertia.

Brief description of the figures

The invention is explained below with reference to the following figures, but the invention is not restricted to the embodiments illustrated in the figures.

Figure 1 shows, in a schematic view, a first embodiment of a machine part;

Figure 2 shows, in a schematic sectional view, an embodiment of an assembly;

Figure 3 shows, in a schematic sectional view, a further embodiment of a machine part in an assembly with a further embodiment of a machine part; and Figure 4 shows, in a schematic partial view, a further embodiment of a machine part in an assembly with a further embodiment of a machine part .

Description of embodiments

Figure 1 shows a machine part 1 with a first housing 3. The first housing has an end-side first housing toothing 5. The teeth 11 of the first housing toothing 5 have tooth flanks 13. The first housing toothing 5 is of self-locking design. The machine part 1 can be coupled via the end-side first housing toothing 5 to a second machine part which has a second housing with a second analogous end-side housing toothing .

The self-locking is achieved by a suitable selection of the flank angles of the tooth flanks. The flank angle is selected in such a manner that the value of the tangent of the flank angle is smaller than the static coefficient of friction. The flank angle refers herein to the angle of a flank in relation to the longitudinal axis of the tooth or in relation to the longitudinal axis of a shaft of the machine part. The coefficient of static friction is determined via the static friction of two touching bodies, i.e. the materials of the two housing toothings. In the embodiment of figure 1, the first housing toothing 5 is composed of steel. In a material pairing with steel, the coefficient of static friction is approximately 0.18. The flank angle of the tooth flanks 13 is 10° and therefore acts in a self-locking manner.

The housing toothing 5 is designed as a Hirth toothing. It has a first jump in diameter 21, and therefore the diameter of the first housing toothing 5 increases in the direction of the end side of the housing 3. The jump in diameter 21 forms a surface which is at least substantially perpendicular with respect to a longitudinal axis A of the housing 3. The surface lies at least substantially in a radial plane. In this embodiment, this surface is designed as an inclined wall which is inclined in relation to a plane which is perpendicular to the longitudinal axis. In the embodiment shown in figure 1, an additional jump in diameter 23 is formed opposite the first jump in diameter 21, as a result of which a groove 27 which is embedded in the first housing toothing 5 is formed. The groove 27 has a groove base 25 along the circumference of the first housing toothing 5.

The first housing toothing 5 has outer edges 17 which are beveled on the end side. The beveled outer edges 17 have a surface running at least substantially obliquely. Inlet surfaces 15 are provided on the tooth tips of the teeth. The tooth tips are chamfered, wherein the inlet surfaces 15 have a geometry tapering in the shape of a roof. The inlet surfaces 15 are inclined in relation to a cross-sectional plane perpendicular to the longitudinal axis A of the housing 3. The teeth 11 each have inlet surfaces 15 which comprise two surfaces which taper in the shape of a roof. The inlet surfaces 15 give rise to a tip at the end of the teeth. In this embodiment, the angle of inclination of the inlet surfaces 15 is 15°.

Figure 2 shows, in a sectional view, a further embodiment of a machine part in a typical assembly. In figure 2 to figure 4, the same reference signs refer to identical or similar parts as in the exemplary embodiment of figure 1.

A securing element 31 is arranged along a first jump in diameter 21, and therefore the securing element 31 lies substantially against the first jump in diameter 21. The securing element 31 typically has a variable inner diameter and can be expanded, for example for removal of the securing element 31. In the assembled state, the securing element is prestressed elastically inwards in the radial direction.

The first jump in diameter as part of a groove which is embedded in the housing toothing is suitable for receiving a securing element. In one embodiment, the securing element is radially elastically expandable and has a resetting force. A second machine part with a second housing has a second housing toothing. The second housing toothing has a second jump in diameter as part of a groove which is embedded in the second housing toothing. In a typical embodiment, the second housing toothing has an outer edge which is beveled on the end side. The outer edge, which is beveled on the end side, of the second housing toothing has a chamfered surface. The features described herein for the first housing are also present in typical second housings.

Directly before the coupling to the first housing, the outer edge, which is beveled on the end side, touches the securing element of the first housing toothing. The outer edge, which is beveled on the end side, of the second housing toothing at least partially expands the securing element on the first housing toothing during the process of coupling the first housing toothing to the second housing toothing. During the expansion, the securing element at least partially loses contact with the jump in diameter of the groove of the first housing toothing.

As the coupling progresses, the outer inlet surfaces of the second housing toothing further expand the securing element and slide under the latter until a first jump in diameter of the second housing toothing has been overcome. The expanded securing element then springs back both into the groove of the first housing toothing and into the groove of the second housing toothing. The return of the securing element into the original expansion width can take place abruptly. The abrupt contact of the securing element with the jumps in diameter can give rise, for example, to a perceptible noise. The successful coupling of the two machine parts can thus be confirmed.

The machine part 1 has a retainer ring 33. The retainer ring 33 is displaceable in its axial position in relation to the housing 3 in the direction of the longitudinal axis A. In a securing position, the retainer ring 33 engages over the first jump in diameter 21. In the securing position, the retainer ring 33 secures the securing element 31 against escaping radially. The radial contact surface 37 along the inner surface of the retainer ring 33 is chamfered, and therefore the inner diameter becomes greater toward the end- side end. In a securing position, the radial contact surface 37 presses the securing element 31 into the groove 27 or holds the securing element there . The retainer ring 33 is prestressed in the axial direction toward the securing position via a spring element 35. For the coupling of the two machine parts, the securing ring has to be moved axially against the spring element 35 in order to permit expansion of the securing element 31.

In a further embodiment, the machine part comprises a first shaft with an end-side shaft toothing. The first shaft and the end-side shaft toothing are connected to each other via a compensating element. The compensating element permits an axially and angularly offset connection of the first shaft to a second shaft. In the embodiment shown in figure 2, the compensating element 41 is designed as a bellows coupling.

Figure 2 shows, in a schematic sectional view, a second machine part 100 with a second housing 103. The teeth 111 of the end-side second housing toothing 105 engage in the teeth 11 of the first housing toothing 5. The second machine part 100 has a second shaft 107 with a second shaft toothing 109. The shaft toothing 109 of the second shaft 107 engages in the matching shaft toothing 9 of the first shaft 7. Engagement of the two matching shaft toothings 9, 109 results in an interlocking connection between the shafts. The shaft toothings are typically designed as groove toothings or Hirth toothings .

Figure 3 shows an assembly consisting of a machine part 1, in a schematic sectional view. The first housing 3 is designed as an engine housing 10 in which an engine is arranged. The machine part 1 is coupled to a second machine part 100 which comprises a second housing 103 with an integral end-side second housing toothing 105. The second housing 103 is designed as a gearbox housing 110 in which a gearbox is accommodated. The end-side first housing toothings 5 of the first housing 3 and the end-side second housing toothing 105 of the second housing 103 intermesh and couple the machine part 1 and the second machine part 100 in an interlocking manner.

In embodiments, the housing toothing is in each case formed integrally with the housing. In further embodiments, the housing toothing and the housing are each individual parts connected in particular in an interlocking or force- fitting manner.

A first groove 27 is formed radially on the outer circumference of the first housing toothing 5. The second housing toothing 105 has a second groove 127. In the schematic sectional view of figure 3, the two grooves 27, 127 are illustrated in superimposed form. The coupling of the two machine parts 1, 100 is secured against axial displacement by means of a securing element 31 introduced into the two grooves 27, 127. The retainer ring 33 secures the securing element 31 by pressing the securing element 31 into the first groove 27 and into the second groove 127. The retainer ring 33 and the securing element 31 secure the assembly against opening. Furthermore, settling movements can be compensated for .

The a ia 11y displaceable retainer ring 33 is clamped in the direction of the second housing 103 by means of a spring element 35. In a further embodiment, the spring element 35 can limit the freedom of movement of the retainer ring 33 in the direction of the first housing 3, and therefore the displaceable retainer ring 33 is fixed in a securing position. By release of the spring element 35, the retainer ring 33 can be brought out of its securing position, for example in order to release the assembly.

In the embodiment shown in figure 3, the first housing 3 comprises a first shaft 7 with an end-side first shaft toothing 9. The second housing 103 comprises a second shaft 107. The first shaft toothing 9 engages in an end-side second shaft toothing 109 of the second shaft 107. The two shaft toothings 9, 109 are each of self-locking design.

The first shaft 7 which is driven by an engine transmits a torque to the gearbox-side second shaft 107. The two self- locking shaft toothings 9, 109 are designed as Hirth toothings. As a result, no axial forces are conducted by the transmitted torques to the bearings 42. Typically, precisely one of the two housings 3, 103 is fixed. When the two housings 3, 103 are coupled, only one of the two housings is therefore moved or else prestressed in the direction of the respective fixed housing. For example, the engine housing 10 is secured against axial displacement and radial rotation. The coupling takes place, for example, by axial displacement of the engine housing 10 in the direction of the gearbox housing 110.

Figure 4 shows schematically an end-side first housing toothing 5 of a machine part 1. The teeth 11 of the first housing toothing 5 engage in a second housing toothing 105 of a second machine part 100. The first housing toothing 5 has a first jump in diameter 21. Figure 4 shows an embodiment in which the jump in diameter 21 is designed as part of a first groove 27 which is embedded in the housing toothing. The second housing toothing 105 has a second jump in diameter 121 which is designed as a second groove 127 which is embedded in the housing toothing.

In a closed state, the two housing toothings 5, 105 completely intermesh. Complete intermeshing refers here to a state with a maximum contact surface of the tooth flanks of the first housing toothing 5 with the tooth flanks of the second housing toothing 105. The first groove 27 of the first housing toothing 5 is arranged here in such a manner that, in the closed state, an axial offset occurs with the second groove 127 of the second housing toothing 105. For clarification in figure 4, the axial offset is not illustrated true to scale. In the embodiment shown in figure 4, the axial offset is 0.1 mm. By means of the axial offset, the prestressing direction of an inserted securing element turns from one tooth 11 to the next tooth 111. The securing element therefore presses against the jump in diameter 21 of the first housing toothing 5 in the direction of the second machine part 100. By contrast, the second jump in diameter 121 of the second housing toothing 105 is pressed in the opposite direction. The two machine parts 1, 100 are pressed against each other by the prestressing of the securing element 31.

Claims

1. Machine part (1) with a first housing (3),

- wherein the first housing (3) has an end-side first housing toothing (5), configured for coupling to an end-side second housing toothing (105) of a second housing (103) of a second machine part (100);

- wherein the machine part (1) comprises a first shaft (7) with an end-side shaft toothing (9) .

2. Machine part (1) according to Claim 1, wherein the first end-side housing toothing (5) is of self-locking des ign .

3. Machine part (1) according to one of the preceding claims, characterized in that the first end-side housing toothing (5) has a flank angle of 15° or less.

4. Machine part (1) according to one of the preceding claims, wherein the first housing toothing (5) has a first jump in diameter (21) .

5. Machine part (1) according to Claim 4, wherein the first jump in diameter (21) is designed as part of a groove (27) which is embedded in the first housing toothing (5)

6. Machine part (1) according to Claim 4 or 5, wherein the jump in diameter (21) has a wall which is inclined in relation to a cross-sectional plane of the machine part (1) ·

7. Machine part (1) according to one of Claims 4 to 6, characterized by a securing element (31) which, in a closed state, lies against the first jump in diameter (21) .

8. Machine part (1) according to one of the preceding claims, characterized by a retainer ring (33) .

9. Machine part (1) according to Claim 8, wherein the retainer ring (33) in the closed state engages over the jump in diameter (21) .

10. Machine part (1) according to one of the preceding claims, wherein the first shaft (7) has a compensating element (41) for compensating for a radial and/or axial offset of the first shaft (7) relative to a second shaft (107) which is to be connected.

11. Machine part (1) according to one of the preceding claims, wherein inlet surfaces (15) are in each case provided on the end surfaces of at least some of the teeth (11) of the first housing toothing (5) .

12. Machine part (1) according to one of Claims 5 to 11, wherein the groove (27) is arranged in such a manner that, in a closed state of a connection to a second housing (103) with a second housing toothing (105) and second groove, an axial offset occurs between the first groove (27) and the second groove (127) .

13. Machine part (1) according to one of the preceding claims, wherein the first housing is an engine housing with an engine accommodated therein, or a gearbox housing with a gearbox accommodated therein.

14. Assembly consisting of a machine part (1) according to one of the preceding claims with a second machine part (100), with a second housing (103) having a second housing toothing (105) matching the first housing toothing (5) .

15. Assembly according to Claim 14, having a first groove

(27) of the first housing toothing and a second groove first groove (27) is designed in such a manner that, when the toothings engage in the closed state, the grooves have an axial offset with respect to each other .