Planetary carrier, planetary gear with the planetary carrier and method for assembling a planetary gear

Abstract

Planet carrier (1), which is formed from several interconnected components (2), and which is provided with an imaginary axially aligned main axis (3) and has at least the following components (2), each formed separately from the other components (2) but interconnected with the planet carrier (1): - one cheek (4), - a second cheek (5), - a third cheek (6), - a set of first planetary bolts (7), - a set of second planetary bolts (8), - first fasteners (9), - second connecting means (10), where, - the second cheek (5) is arranged in an axial direction aligned with the main axis (3) between the first cheek (4) and the third cheek (6) and is provided with first through holes (11) for the first planet bolts (7) and the second planet bolts (8), - the first cheek (4) and the second cheek (5) are connected to each other by means of the first connecting means (9), - the second cheek (5) and the third cheek (6) are detachably connected to each other by means of the second connecting means (10), and wherein each of the planet bolts (7, 8) is seated in one of the first through holes (11) and is axially fixed at its end in one direction parallel to the main axis (3) on the first cheek (4) and in the other direction axially on the third cheek (6), and wherein the first cheek (4) and the third cheek (6) are held axially apart from each other by means of at least some of the planet bolts (7, 8).

Description

Field of invention

[0001] The invention relates to a planet carrier made of several interconnected components, comprising: - a first cheek, - a second cheek, - a third cheek, - a set of first planetary bolts, - a set of two planetary bolts, - first connecting elements, - second connecting means, where, - the second cheek is arranged in an axial direction aligned with the main axis between the first cheek and the third cheek and is provided with first through holes for the first planet bolts and the second planet bolts, - the first cheek and the second cheek are connected to each other by means of the first connecting means and - the second cheek and the third cheek are detachably connected to each other by means of the second connecting means.

[0002] The invention further relates to a planetary gear with a set of first planet gears and a set of second planet gears, wherein each of the first planet gears is mounted on one of the first planet bolts between the first web and the second web at a radial distance to the main axis, rotatable about a first bolt axis of the respective first planet bolt, and wherein each of the second planet gears is mounted on one of the second planet bolts between the second web and the third web at a radial distance to the main axis, rotatable about a second bolt axis of the respective second planet bolt. The invention also relates to a method for assembling such a planetary gear with such a planet carrier. Background of the invention

[0003] The invention relates to planetary gear sets whose planet carriers have at least two chambers separated from each other by a partition. Each chamber accommodates at least one set of planet gears. A distinction is made between one-piece planet carriers and so-called "built-up" planet carriers assembled from individual parts. Advantages of the generic "built-up" planet carriers compared to the one-piece and cast planet carriers described, for example, in DE 740 15 23 U, are their lower manufacturing and assembly costs. With one-piece planet carriers, internal machining of the carrier elements in the contact area of ​​the rolling bearings and planet gears can be problematic, as the areas suitable for machining are difficult to access. However, one-piece planet carriers can advantageously be designed to be very rigid.In known planetary gears of the prior art according to DE 10 2012 208 798 A1, planet carriers formed from a cast part and sheet metal parts are used. Such arrangements represent a compromise solution with regard to stiffness and manufacturing costs. Planetary gears that are welded constructions assembled from individual components are also known from US 2006 122 020 AA. Sheet metal components are predominantly used for these. The disadvantage of such constructions can lie in the difficulty of assembly and the lack of disassembly. The sheet metal components are sometimes bulky formed parts, for which high tooling, storage, and handling costs can be incurred.

[0004] DE 11 2012 003 445 T5, DE 10 2011 003 706 A1, DE 20 2006 016 324 U1, DE 10 2016 207 535 A1 and DE 10 2014 208 003 A1 each disclose devices with planetary gears or at least parts of such gears. Description of the invention

[0005] The purpose of the invention is to create a planetary gear that is easy and inexpensive to manufacture yet rigid.

[0006] The problem is solved according to the subject matter of claim 1 and a further independent claim.

[0007] The invention provides a planet carrier or support structure in a planetary gear unit, which is formed from simple sheet metal components. The connection between the components is at least partially detachable and serves to provide axial preload to the carrier or support structure of the planetary gear unit.

[0008] The planet carrier has at least the following components: - a first cheek, - a second cheek, - a third cheek, - a set of first planetary bolts, - a set of two planetary bolts, - first fasteners and - second connecting means.

[0009] The cheeks, preferably as flat sheet metal parts made of sheet steel, can be easily manufactured by punching, punching, and embossing sheet steel and are easy to store and handle. They are not bulky compared to prior art designs, as the fasteners are separate components.

[0010] An intermediate cheek, referred to as the second cheek, is arranged axially between the first and third lateral cheeks. This creates two chambers. The first chamber is axially bounded by the first and second cheeks. The second chamber is axially bounded by the second and third cheeks. The cheeks are axially connected to each other in series via connecting elements; that is, the first cheek is connected to the second cheek via first connecting elements, and the second cheek is connected to the third cheek via second connecting elements. At least the connection between the second and third cheeks is a positive-locking or force-locking connection, preferably formed by screws. Assembly and disassembly are simplified. Screws are standard parts that are readily available and inexpensive.

[0011] In the planetary gear system covered by the invention, at least one set of planet gears is installed in the chamber to the left of the intermediate wall and at least one set in the chamber to the right of the intermediate wall. The planet gears of the sets, both among themselves and within individual sets, may differ from one another or be identical in their design. Each set of first planet gears is associated with a set of first planet bolts. Each first planet gear is rotatably mounted on a first planet bolt. The second planet gears are each rotatably mounted on a second planet bolt of the other set.

[0012] According to the invention, the first and second planetary gear bolts are designed to be long enough to extend from the first lateral cheek to the third lateral cheek through through-holes in the intermediate cheek and thus through both chambers. The ends of the planetary gear bolts are secured in receptacles in the cheeks. The first cheek and the third cheek are held axially apart by the planetary gear bolts, the distance between these cheeks being determined by the length of the planetary gear bolts. Furthermore, the planetary gear bolts are axially guided and radially supported in their respective through-holes in the intermediate cheek by means of a clearance, transition, or interference fit. In the first chamber located between the first cheek and the second cheek, only the first planetary gear bolts are fitted with first planetary gears. The sections of the second gear bolts extending axially through the first chamber are not fitted with planetary gears.In the second chamber, located between the second cheek and the lateral third cheek, only the second planetary bolts are fitted with second planetary gears. The sections of the first bolts extending axially through the second chamber are not fitted with planetary gears. This "extension" of the planetary bolts across both chambers creates a stiffer planet carrier or support structure for the planetary gear set, capable of withstanding high operating forces. This is because the robust planetary bolts serve as additional axial, torsional, and / or bending supports. The latter is particularly true when, as provided in one embodiment of the invention, at least some of the planetary bolts are clamped axially aligned with the main axis between the first cheek and the third cheek. The planet carrier orThe planetary gear's support structure is axially prestressed, resulting in high stiffness while maintaining adapted flexibility at the planet carrier. The prestressing is achieved through secondary fasteners, which generate tensile stresses between the intermediate web and the third web. These secondary fasteners are subjected to tensile stresses axially in directions aligned with the main axis. Preferably, these secondary fasteners are bolts that engage in a positive-locking, force-locking manner with an internal thread on the intermediate web. Tensile stresses are generated via this bolted connection.

[0013] The aforementioned arrangement requires that the connecting elements of the first and second cheeks be able to withstand the tensile stresses and therefore be firmly connected to each other. Therefore, one embodiment of the invention provides that the first connecting elements are components made of sheet steel, which are permanently connected to the first and second cheeks, preferably by metallurgical connections such as welded joints.

[0014] The aforementioned connection technology according to the invention makes it possible to pre-tension the planet carrier or the support structure of the planetary gear unit via the screws after assembly. The pre-tension can be individually adjusted via the elongation behavior of the screws and the other material, as well as via the tightening torque of the screw connection. In this process, the outer lateral webs, i.e., the first and third webs, are pulled axially against the planet bolts, so that the planet bolts are subjected to compression and the connecting elements to tension.

[0015] One embodiment of the invention provides that the internal threads are each formed at least partially in a first bead that projects at least partially axially beyond the cheek and is fixed to the cheek. The respective bead is either attached to the cheek or formed integrally with the cheek and thus made of the same material as the cheek.

[0016] A further embodiment of the invention provides that the planetary bolts are received radially in the second through-holes of the first and third cheeks, respectively. These second through-holes are each provided with a radial constriction, i.e., a constriction directed transversely to the main axis. The respective planetary bolt received in the respective second through-hole is supported axially at the constriction and radially within the through-hole.

[0017] This ensures that the respective planetary bolt is securely fixed radially and axially at its end in the respective cheek and that the arrangement can be securely clamped.

[0018] The respective constriction is formed by a second bead fixed to the first and / or second cheek. At least one axial stop, preferably a flat circular surface, is formed in the second through-hole of the second bead. The respective planetary bolt is axially supported by this at least one axial stop. The respective bead is either placed on the cheek and fastened there. A bead with an internal thread can therefore also be a commercially available suitable nut. A bead with an axial stop can be a mounted disc whose through-hole forms the constriction. Preferably, however, the respective bead is formed from the same material as the steel sheet of the cheeks and is therefore integral with the respective cheek. The advantage of this design is that the production of the bead can be carried out in the stamping or die-casting machines without significantly increased effort.The forming process for manufacturing the cheek can be integrated, thus avoiding additional steps for securing the bead. Internal threads are cut into the bead on the cheek, and axial stops are embossed onto the bead.

[0019] The subject matter of the patent claim is directed to a planetary gear system with at least two planetary gear sets and the components of the planet carrier, wherein the components of the planet carrier form the support structure of the planetary gear system. The planetary gear system may include further gears, such as sun gears and ring gears, as well as further planetary gears or planetary gear sets and other components.

[0020] For technical and economic reasons, the assembly of the planetary carrier according to the invention is integrated into the assembly of the planetary gear set. The planetary carrier can only be assembled economically if the planet gears and other gears of the planetary gear set are assembled simultaneously and in a stepwise, alternating manner. The invention therefore also provides a method for manufacturing and assembling a planetary gear set. The procedure is as follows:

[0021] Method for manufacturing / assembling a planetary gearbox comprising the following steps: - Preparing the components of the planet carrier, preferably by cold forming from sheet steel, and providing the planet gears and other gears and components; - Connecting or assembling the cheeks with other components, such as preparing a mounting for a ring gear or mounting bearing seats in the cheeks; - Creating material-bonded first connections between the first cheek and the first connecting means, preferably by welding; - Inserting the first planet bolts into the first cheek, preferably into the first through holes, and possibly securing or fastening the first planet bolts in the first through holes; - Mounting the first planet gears, possibly also planet bearings, spacers and thrust washers onto the first planet bolts; - Sliding the second cheek onto the first planetary bolts, with the second cheek being guided over the first planetary bolts; - Creating material-bonded second connections between the second cheek and the first connecting means, preferably by welding; - Insert the second planetary bolts into the first cheek, each of the second planetary bolts first being guided axially through one of the remaining free through-holes in the first. If necessary, secure the second planetary bolts in the first through-holes; - Mounting the second planet gears onto the second planet bolts, and possibly other gears, such as sun gears, including their bearings and spacers and other components, such as springs; - Placing the third cheek on the planetary bolts; - Inserting the screws into the third through holes; - Screwing the third cheek to the second cheek using the second connecting elements designed as screws, as well as - axial clamping of the first cheek and third cheek against each other by tightening the screws with suitable tightening torques. Description of the drawings

[0022] The invention is explained in more detail below using an exemplary embodiment. Fig. Figure 1 shows an overall view of an embodiment of a planetary gear 20. The planetary gear 20 and its components 2 are oriented around an imaginary axially aligned main axis 3. The planetary gear 20 is provided with the following components 2: - a set of first planetary gears 16, - two sets of second planetary gears 17, - one cheek 4, - a second cheek 5, - a third cheek 6, - first connecting means 9, - second connecting means 10 and - a lubrication device 28. The first planet gears 16 are located between the first web 4 and the second web 5 at a radial distance from the main axis 3. The second planet gears 17 are located at a radial distance from the main axis 3 between the second web 5 and the third web 6. The first web 4 and the second web 5 are permanently connected to each other by means of the first connecting elements 9 and are held axially apart from each other by means of the first connecting elements 9, aligned with the main axis 3. The second web 5 and the third web 6 are detachably connected to each other by means of the second connecting elements 10. Fig. Figure 2 shows the planet carrier 1 of the planetary gear 20 in an overall view. Fig. Figure 3 shows the planet carrier 1 in a side view. Fig. Figure 4 shows a longitudinal section through a section of the planet carrier 1 along the bolt axis 18 or 19 of the planet bolts 7 or 8, which shows the seat of the planet bolt 7 or 8 in the through holes 11 or 14. Fig. Figure 5 shows an exploded view of the planet carrier 1 or a support structure of the planetary gear 20. Fig. Figure 6 shows a partial section through the planet carrier 1 at a threaded connection 13.

[0023] Fig. 2, Fig. 3 and Fig. 5 - The planet carrier 1 is formed from several interconnected components 2 and is aligned concentrically to the axially aligned main axis 3. It has at least the following features, each separate from the other components 2 ( Fig. 5) trained but to the planetary carrier 1 ( Fig. 2 and Fig. 3) interconnected components 2 on: - the first cheek 4, - the second cheek 5, - the third cheek 6, - a set of first planetary bolts 7, - a set of two planetary bolts 8, - the first connecting elements 9, - the second connecting elements 10, - a connecting element 32 for a ring gear not shown and - a bearing seat 30

[0024] The first cheek 4 is provided with second through holes 14 and has a central opening 33. The second cheek 5 has through holes 11 and a central opening 33 and is provided with beads 23. The third cheek 6 has through holes 14 and third through holes 29. Furthermore, the third cheek 6 is provided with a bearing seat 30 and beads 26.

[0025] The second cheek 5 is arranged axially in the same direction as the main axis 3 between the first cheek 4 and the third cheek 6 and is provided with first through holes 11 for the first planet bolts 7 and the second planet bolts 8. The first cheek 4 and the second cheek 5 are connected to each other by means of the first connecting elements 9 and material-bonded connections 21 and 22. The second cheek 5 and the third cheek 6 are detachably connected to each other by means of the second connecting elements 10.

[0026] The second connecting elements 10 are screws 12, which are inserted through the third through holes 29, forming a threaded connection 13 with the second cheek 5. The first planetary bolts 7 of one set and the second planetary bolts 8 of the other set are of the same length. However, the diameter of the first planetary bolts 7 is larger than the diameter of the second planetary bolts 8.

[0027] Each of the planetary bolts 7 and 8 is seated in one of the first through holes 11 and the second through holes 14, respectively, and is axially fixed at its end in one direction aligned with the main axis 3 in the respective through hole 14 on the first cheek 4 and in the other direction axially on the third cheek 6. The first cheek 4 and the third cheek 6 are held axially apart from each other by means of at least some of the planetary bolts 7 and 8.

[0028] Fig. 6 - The second cheek 5 is made of sheet steel. The first beads 23 are formed on the cheek 5. The beads 23 are formed by drawing or embossing on the cheek 5 and are thus integral with the cheek 5, so that they project axially beyond the end face 31 of the cheek 5. They are provided with an internal thread 24. One of the screws 12 with an external thread 25 engages in the respective internal thread 24.

[0029] Fig.4 - The first cheek 4 and the third cheek 6 are components 2 made of sheet steel and are provided with second through-holes 14. At least some of the planetary bolts 7 and 8 are radially received in the second through-holes 14. The second through-holes 14 are each provided with a radial constriction 15, i.e., directed transversely to the bolt axis 18 and 19, respectively. The respective planetary bolt 7 and 8 received in the respective second through-hole 14 is axially supported against an axial stop 27 of the constriction 15. The constriction 15 at the bead 23 is formed as a single piece with the third cheek 6 and is plastically displaced from the sheet steel of the respective cheek 4 as a bead 26 during the forming of the cheek 6. In this process, the axial stop 27 is formed. The bead 26 projects axially beyond the end face 31 of the cheek 6. The constriction 15 on the third bead 36 is a hole aligned with the through hole 14 in a disc 34 placed on the cheek 4.in a molded part 34, which is attached to the cheek 4 by means of welds 35. The axial stop 27 is formed at this point by a flat surface of the disc 34. Reference symbol list 1 Planetary Carrier 2 components 3 Main axis 4 first cheek 5 second cheek 6 third cheek 7 first planetary bolt 8 second planetary bolt 9 first connecting element 10 second connecting element 11 first through hole 12 screws 13 Threaded connection 14 second through hole 15 Narrowing 16 first planetary gear 17 second planetary gear 18 first bolt axis 19 second bolt axis 20 planetary gears 21 first material-bonded connection 22 second material-bonded connection 23 first bulge 24 internal threads 25 external threads 26 second bulge 27 Axial stop 28 Lubrication device 29 third through hole 30 bearing seat 31 Front 32 Connection element 33 central opening 34 Disc / Molded Part 35 welds 36 third bulge

Claims

[1] Planet carrier (1) which is formed from several interconnected components (2) and which is provided with an imaginary axially aligned main axis (3) and has at least the following components (2) which are each formed separately from the other components (2) but are interconnected to form the planet carrier (1): - one cheek (4), - a second cheek (5), - a third cheek (6), - a set of first planetary bolts (7), - a set of second planetary bolts (8), - first fasteners (9), - second connecting means (10), where, - the second cheek (5) is arranged in an axial direction aligned with the main axis (3) between the first cheek (4) and the third cheek (6) and is provided with first through holes (11) for the first planet bolts (7) and the second planet bolts (8), - the first cheek (4) and the second cheek (5) are connected to each other by means of the first connecting means (9), - the second cheek (5) and the third cheek (6) are detachably connected to each other by means of the second connecting means (10), and wherein each of the planet bolts (7, 8) is seated in one of the first through holes (11) and is axially fixed at its end in one direction in the same direction as the main axis (3) on the first cheek (4) and in the other direction axially on the third cheek (6), and wherein the first cheek (4) and the third cheek (6) are held axially apart from each other by means of at least some of the planet bolts (7, 8). [2] Planet carrier according to claim 1, in which at least some of the planet bolts (7, 8) are clamped axially in the same direction as the main axis (3) between the first cheek (4) and the third cheek (6), wherein the second connecting means (10) are subjected to tensile stress axially in the directions in the same direction as the main axis (3). [3] Planetary carrier according to claim 1 or 2, in which the cheeks (4, 5, 6) are made of sheet steel, wherein at least one of the cheeks (5) has internal threads (24) formed in the sheet steel, and wherein the respective internal thread (24) is formed at least partially in a first bead (23) which extends at least partially axially beyond the cheek (4, 5, 6) and is fixed to the cheek. [4] Planetary carrier according to claim 3, in which the second connecting means (10) are screws (12), wherein the screws (12) engage in a threaded connection (13) in the second cheek (5) formed from the internal thread (24) on the second cheek (5) and an external thread (25) of the respective screws (12). [5] Planet carrier according to claim 1 or 2, in which at least the first cheek (4) and the third cheek (6) are components (2) made of sheet steel and are provided with second through holes (14), wherein at least some of the planet bolts (7, 8) are received radially in the second through holes (14), and wherein the second through holes (14) are each provided with a radial, i.e., transverse to the main axis (3) constriction (15), wherein the respective planet bolt (7, 8) received in the respective second through hole (14) is axially supported on the constriction (15). [6] Planet carrier according to claim 5, in which the respective constriction (15) is formed by a second bead (26, 36) fixed to the first cheek (4) or third cheek (6), wherein at least one axial stop (27) is formed on the second bead (26, 36) in the second through hole (14), and wherein the respective planet bolt (7, 8) is axially supported on the at least one axial stop (27). [7] Planet carrier according to claim 3 or 6, in which each of the bulges (23, 26) is formed in one material with the steel sheet of those of the cheeks (5, 6) and is therefore formed in one part with the respective cheek (5, 6). [8] Planetary carrier according to claim 1 or 2, in which the first connecting means (9) are components made of sheet steel which are inseparably connected to the first cheek (4) and the second cheek (5). [9] Planetary gear (20) which has an imaginary axially aligned main axis (3) and which is provided with at least the following components (2): - a set of first planetary gears (16), - a set of two planetary gears (17), - one cheek (4), - a second cheek (5), - a third cheek (6), - a set of first planetary bolts (7), - a set of second planetary bolts (8), - first fasteners (9), - second connecting means (10), wherein - the second cheek (5) is arranged in an axial direction aligned with the main axis (3) between the first cheek (4) and the third cheek (6) and is provided with first through holes (11) for the planet bolts (7, 8), - each of the planet bolts (7, 8) is seated in one of the first through holes (11) and is radially and axially supported at its end in one direction on the first cheek (4) and in the other direction on the third cheek (6), and wherein the first cheek (4) and the third cheek (6) are held at a distance from each other axially by means of at least some of the planet bolts (7, 8) aligned with the main axis (3), - each of the first planet gears (16) is mounted on one of the first planet bolts (7) between the first web (4) and the second web (5) at a radial distance to the main axis (3) about a first bolt axis (18) of the respective first planet bolt (7), - each of the second planet gears (17) is mounted on one of the second planet bolts (8) between the second web (5) and the third web (6) at a radial distance to the main axis (3) about a second bolt axis (19) of the respective second planet bolt (8), rotatably. - the first cheek (4) and the second cheek (5) are inseparably connected to each other by means of the first connecting means (9) and are held at a distance from each other axially in the same direction as the main axis (3) by means of the first connecting means (9), - the second cheek (5) and the third cheek (6) are detachably connected to each other by means of the second connecting means (10). [10] Planetary gear (20) according to claim 9, in which at least some of the planet bolts (7, 8) are clamped axially in the same direction as the main axis (3) between the first cheek (4) and the third cheek (6), wherein the second connecting means (10) are subjected to tension axially in the directions in the same direction as the main axis (3). [11] Planetary gear (20) according to claim 9 or 10, in which the first cheek (4) and the third cheek (6) are provided with second through holes (14), wherein at least some of the planet bolts (7, 8) are received radially in the second through holes (14), and wherein the second through holes (14) are each provided with a radial, i.e., transverse to the main axis (3) constriction (15), wherein the respective planet bolt (7, 8) received in the respective second through hole (14) is axially supported on the constriction (15). [12] Planetary gear (20) according to claim 9, 10 or 11, in which the first connecting means (9) are components made of sheet steel and the second connecting means (10) are screws (12). [13] Planetary gear (20) according to claim 12, in which the second cheek (5) and the third cheek (6) are held axially apart from each other by means of the at least some planet bolts (7, 8) and the first connecting means (9) in the same direction as the main axis (3). [14] Method for assembling a planetary gear (20) according to claim 9, comprising at least the following steps: - Forming material-bonded first connections (21) between the first cheek and the first connecting elements (9), - Inserting the first planetary bolts (7) into the first cheek (4), - Mounting the first planet gears (16) onto the first planet bolts (7), - Sliding the second cheek (5) onto the first planetary bolts (7), wherein the second cheek (5) is guided over a number of first through holes (11) corresponding to the number of first planetary bolts (7) onto the first planetary bolts (7), - Forming material-bonded second connections (22) between the second cheek (5) and the first connecting elements (9), - Inserting the second planet bolts (8) into the first cheek (4), each of the second planet bolts (8) being first guided axially through one of the first through holes (11), - Mounting the second planet gears (17) onto the second planet bolts (8), - Placing the third cheek (6) onto the planetary bolts (7, 8), - Screwing the third cheek (6) to the second cheek (5) using the second connecting means (10) designed as screws (12) and - axially clamping the first cheek (4) and third cheek (6) against each other by tightening the screws (12).

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