DE102019201552A1 - Mounting of a planetary gear on a planetary pin connected to a planet carrier and method for mounting a planetary gear on a planetary pin - Google Patents

Abstract

A bearing of a planet gear (8) on a planet pin (3) connected to a planet carrier (1) has a double-row rolling bearing (12), the rolling element rows (15 and 16) of which are provided with inclined rolling elements (17) in an O-arrangement for receiving both radial and axial forces are formed. Furthermore, the roller bearing (17) consists of separate inner rings (13 and 14) guided on the planetary pin (3), both outer races (10 and 11) of the roller bearing (12) being formed on a common component. A first inner ring (13) rests by means of its outer end face (13a) on an annular shoulder (6) formed on the planet pin (3), and a second inner ring (14) is on its outer end face (26) in the axial direction on the planet pin (3 ) supported. To improve the function of an axial fixation of a bearing of a planet gear, the planet pin (3) is used to axially support the outer end face (26) of the second inner ring (14) at an end of the support section (5) facing away from the annular shoulder (6) to form an annular surface (24) gradually reduced in diameter, with a support disk (27) resting on both the outer end face (26) of the second inner ring (14) and the annular surface (24) being supported in a self-adjusting manner axially via the support section (5).

Description

The invention relates to a bearing of a planet gear on a planet pin connected to a planet carrier with a double-row rolling bearing, the rolling element rows of which are provided with inclined rolling elements and are designed in an O-arrangement to absorb both radial and axial forces and have separate inner rings guided on a support section of the planetary pin Both outer races of the roller bearing are formed on a common component and a first inner ring rests against an annular shoulder formed on the planetary pin by means of its outer end face and a second inner ring is supported on its outer end face in the axial direction on the planet pin.

The invention also relates to a method for assembling a double-row tapered roller bearing with inclined rolling elements on a planetary pin, the tapered roller bearing having separate inner rings guided on a support section of the planetary pin and both outer races of the tapered roller bearing being formed on a common component and in the In the assembled state, a first inner ring rests against an annular shoulder formed on the planetary pin by means of its outer end face and a second inner ring is supported on its outer end face in the axial direction on the planet pin

In a conventional structure of a planetary stage, such as a stationary transmission, the planetary gears mesh with those of a sun gear and a ring gear. In the past, planet gears of a gear set were mostly rotatably guided by means of a sliding bearing on the corresponding planet pins, which are components of a planet carrier. In order to create a low-friction bearing, in particular in the case of wheel sets with comparatively large dimensions, such plain bearings are now being replaced by roller bearings. An essential aspect in the structural design of a planetary gear is to minimize the noise resulting from the meshing of the wheels.

For this purpose, the gears, i.e. both the planet gears, the ring gear and the sun gear, can be provided with helical teeth. The forces acting on the planet gears and thus on the bearing must be supported on the planet carrier, and therefore roller bearings with inclined rolling elements are used, which can be acted upon with both radial and axial forces. These absorb the axial forces transmitted from the tooth mesh to the respective planetary gear and transmit them to the planetary carrier. Since this can also involve load changes, the rolling bearings are provided with two rows of rolling bodies, each of these rows of rolling bodies being provided to absorb an axial force in one of the two axial directions.

With a so-called O-arrangement of the bearing rows, the pressure angles projected onto the longitudinal axis of the planetary pin together form a parallelogram. Double-row angular contact roller bearings in an O-arrangement result in a relatively rigid bearing that is suitable for absorbing high torques.

In generally known solutions, two inner rings of a tapered roller bearing sit on a support section of the planetary pin and are usually axially fixed by means of a securing ring snapped into a circumferential groove of the planetary pin. Due to tolerances that lead to a large adjustment range, very different conditions can arise, ranging from strong axial preload to impermissible axial play of the tapered roller bearing. In both cases this can lead to a reduction in the service life of the rolling bearing.

A bearing of a planet gear on a planet pin connected to a planet carrier with a double-row angular contact roller bearing of the type specified in the preamble of claim 1 is from DE 10 2015 216 849 A1 known. A double-row tapered roller bearing is used to mount the planetary gear on the planetary pin. The planet carrier has two mutually spaced side walls, between which the planet gear provided with the tapered roller bearing is arranged. One cheek is provided with a through hole through which the planet pin, penetrating the inner rings of the tapered roller bearing, is inserted into a blind hole in the other cheek. There is no interference fit between the planet pin and the planet carrier. In the area of the edges of the blind hole and the through hole, on the one hand, a support ring ring and, on the other hand, an intermediate ring bear against the cheek and on the outer end faces of the inner rings. The support ring, which is inserted into an annular groove in the planetary pin, can be divided into two ring halves or slotted on its circumference.

The planetary pin has a radially protruding collar, which is referred to as a cylindrical section with a larger diameter and with which it is guided in the through hole of the cheek. Axially running threaded pins are arranged in this collar and can be adjusted in the direction of the intermediate ring. An axial force can be exerted on an intermediate ring via the manually adjustable set screws. This leads Intermediate ring continues an axial force applied to it by the threaded pins to the inner ring of the first row of rolling elements. The axial force is transmitted via a spacer, the tapered rollers of the second row of rolling elements, the planetary gear, the tapered rollers of the first row of rolling elements and the inner ring of the second row of rolling elements to the support ring and thus the planetary pin and the cheek. The first row of rolling elements, the planetary gear, the spacer and the second row of rolling elements can be adjusted between the support ring and the intermediate ring in such a way that any play that occurs in the double-row angular contact ball bearing due to tolerances is compensated for.

Furthermore, from the publications DE 1 813 409 A a device for maintaining the axial bearing play in rolling bearing installations is known, two individual tapered roller bearings of a rolling bearing arrangement being assigned to rings made of materials with different coefficients of thermal expansion. These overlap with conical inner and outer surfaces. These rings are used to compensate for the relative changes in length of the housing and shaft that occur when a shaft is supported in a housing during operational temperature changes, if these are made of different materials with different coefficients of thermal expansion. Such behavior can be determined, for example, when the shaft is made of steel and the housing is made of an aluminum alloy. The shaft has a smaller thermal expansion than the housing.

In addition, from the DE 10 2009 032 698 A1 a single-row tapered roller bearing is known in which a load compensation body consisting of a closed ring is arranged between a guide rim of an inner ring and end faces of the rolling bodies. This is essentially of inflexible design and is mounted in a radially floating manner. Its wedge-like design has the effect that it is displaced by rolling elements in the load zone and, in turn, causes the rolling elements to be displaced in the unloaded zone.

It is the object of the present invention to provide a bearing of a planetary gear with an axial fixation, the function of which is improved.

This object is achieved on the basis of the preamble of claim 1 in conjunction with its characterizing features. The subsequent dependent claims each reproduce advantageous developments of the invention.

According to the invention, a bearing of a planet gear on a planet pin connected to a planet carrier is designed as a double-row rolling bearing, the rolling element rows of which are provided with inclined rolling elements in an O-arrangement for absorbing both radial and axial forces. Furthermore, the roller bearing consists of separate inner rings guided on a support section of the planetary pin, both outer raceways of the roller bearing being formed on a common component. A first inner ring rests, by means of its outer end face, on an annular shoulder formed on the planet pin, and a second inner ring is supported on its outer end face in the axial direction on the planet pin.

Both outer raceways of the roller bearing can consequently be formed directly on an inner circumferential surface of the planetary gear or on an outer ring pressed into the planetary gear. The first inner ring, which is arranged separately from the second inner ring, rests against an axial stop which is designed as an annular shoulder formed on the planetary pin. The axial support or fixing engages at the end of the support section facing away from the annular shoulder and thus the roller bearing arrangement.

According to the invention, the diameter of the planet bolt for axially supporting the outer end face of the second inner ring at an end of the support section facing away from the annular shoulder is reduced in a stepwise manner to form an annular surface, with a support disc resting on both the outer end face of the second inner ring and the annular surface is supported in a self-adjusting manner on a section projecting axially over the support section and thus the area of the annular surface. The support disk has radial dimensions such that one of its end faces rests against both the end face of the inner ring and the annular face of the planetary pin. For this purpose, the support disk projects radially beyond the ring surface and with this part rests against the end face of the inner ring. This results in a defined support of the roller bearing, and the tolerances occurring outside of the support section no longer affect the preload in the roller bearing.

In contrast, are in the double row rolling bearings after DE 10 2015 216 849 A1 Adjusting devices designed as threaded pins are provided, with which a displacement of the roller bearing relative to the planetary pin is limited in the axial direction, the threaded pins being manually adjusted in the direction of the intermediate ring. The planet bolt is therefore fixed in the planet carrier by means of the threaded pins in connection with a securing ring arranged in one cheek. If the clearance is to be compensated, the intermediate ring must be pretensioned to a greater or lesser extent using the threaded pins.

In a further embodiment of the invention, the self-adjusting support is designed as a radially inwardly resiliently pretensioned ring engaging with radial and axial play in a circumferential groove of the planetary pin, one end face of the ring facing away from the outer end face of the second inner ring , runs at an acute angle to its transverse plane. It is first achieved that by means of the support disk arranged between the ring and the outer end face of the second inner ring, an area of the inner ring provided with a radius is covered and, on the other hand, the ring used for adjustment always lies flat against this support disk during its adjusting movements. Compared to known solutions, the support disk also ensures that a locking ring that interacts with the outer end face does not tilt under an axial force.

The inclined end face of the ring acts as an inclined plane with a side wall of the ring groove. Since the ring is preloaded radially inwards, it transmits a force to the support disk in the axial direction and holds it against the ring surface of the planetary pin without play. The adjustment device also acts on the outer face of the second inner ring and ensures that it is aligned with the ring surface. The roller bearing should be essentially free of play so that its service life is not impaired. Since too large an axial play of the tapered roller bearings and a large axial preload would have a detrimental effect on the service life, the distance given between an annular stop surface of the annular shoulder and the support disk should be designed so that both are avoided.

The end face of the ring running at an acute angle is preferably guided on a parallel flank of the ring groove. The flank of the annular groove, which is parallel to the end face of the ring, results in a flat contact between the ring and the flank, so that the ring is guided in a sliding manner on this. The bevels of the bevel of the ring and the flank of the circumferential groove are designed in such a way that this adjustment system is self-locking and axial loads on the ring do not lead to its expansion.

It is particularly advantageous if the roller bearing is designed as a double-row tapered roller bearing. Alternatively, there is also the possibility of designing the roller bearing as a double-row angular roller bearing or as a double-row angular contact ball bearing. In contrast to tapered roller bearings, the rolling elements in tapered roller bearings are cylindrical. Double-row angular contact ball bearings have advantages over tapered roller bearings and tapered roller bearings in that the sliding friction occurring between the end faces of the tapered rollers or the tapered rollers and edge surfaces of the guide rims of the inner rings can be avoided. This sliding friction can lead to premature wear on the edge surfaces and the end surfaces of the rollers. In addition, the higher frictional torque and friction between the rolling elements on the raceways can cause the bearing temperature to rise and, consequently, the oil temperature of the planetary gear.

In a further embodiment of the invention, the rolling elements of the two rows of rolling bearings can be guided in at least one rolling bearing cage. An arrangement of the rolling elements in at least one rolling bearing cage has the advantage over a full complement arrangement of the rolling elements that they are guided in such a way that they do not tend to twist. This entanglement would also lead to increased sliding friction on the end faces of the rollers, as a result of which a premature failure of the bearing would have to be feared due to higher wear.

Furthermore, the outer raceways of the double-row tapered roller bearing can be formed in an inner circumferential surface of the planetary gear. The inner circumferential surface of the planetary gear consequently has a profile, part of which are the two outer raceways running at an angle to the longitudinal axis of the tapered roller bearing. As an alternative to this, there is of course also the possibility of designing the inner circumferential surface of the planetary gear to be cylindrical and thus of pressing an outer ring of the double-row tapered roller bearing into the planetary gear.

Finally, according to the invention, a method for assembling a double-row tapered roller bearing with obliquely positioned rolling elements is provided on a planetary pin. The tapered roller bearing has separate inner rings guided on a support section of the planetary pin, and both outer raceways of the tapered roller bearing are formed on a common component. In the assembled state of the planet gear mounted on the planet pin, a first inner ring should rest against an annular shoulder formed on the planet pin by means of its outer end face and a second inner ring should be supported on its outer end face in the axial direction on the planet pin.

According to the invention, the tapered roller bearing is first inserted into the planetary gear together with a support disk resting on the outer end face of the second inner ring. Then this unit is pushed onto the support section by means of a device until the support disk is formed on one at the end of the support section Ring surface rests. This results in a defined position of the tapered roller bearing in which it is mounted without tension. Finally, a ring provided radially on the inside with a bevel is inserted into a circumferential groove of the planetary pin, the end face resting on the support disk with a flat surface.

The invention is not restricted to the specified combination of the features of the main claim and the patent claims dependent thereon, as well as to the features of the independent method claim. In addition, there are possibilities of combining individual features with one another, also insofar as they emerge from the patent claims, the following description of preferred embodiments of the invention or directly from the drawings. The reference of the claims to the drawings through the use of reference signs is not intended to limit the scope of protection of the claims.

• 1 einen Teillängsschnitt durch einen Planetenbolzen eines Planetenträgers mit einem Planetenrad, das über ein doppelreihiges Kegelrollenlager auf diesem gelagert ist, wobei zwischen dem Planetenbolzen und einer Stirnseite eines Innenringes des Kegelrollenlagers eine erfindungsgemäße Nachstelleinrichtung und eine Stützscheibe angeordnet sind,
• 2 einen im Maßstab vergrößerten Ausschnitt II aus der Anordnung nach der 1, aus dem eine aus einem Ring, einer Umfangsnut und einer Stützscheibe bestehende Nachstelleinrichtung hervorgeht, und
• 3 eine Draufsicht auf den als Einzelteil dargestellten Ring.

Advantageous embodiments of the invention, which are explained below, are shown in the drawings. Show it:

• 1 a partial longitudinal section through a planet pin of a planet carrier with a planet gear, which is mounted on this via a double-row tapered roller bearing, with an adjustment device according to the invention and a support disk being arranged between the planet pin and an end face of an inner ring of the tapered roller bearing,
• 2 an enlarged section II from the arrangement according to the 1 , from which an adjustment device consisting of a ring, a circumferential groove and a support disk emerges, and
• 3 a plan view of the ring shown as a single part.

In the 1 1 denotes a planet carrier which is only partially, that is, in the area of a disk-shaped base part 2 and a planet bolt formed on this 3 is shown. The planet carrier 1 has a plurality of appropriately designed planetary pins which, evenly distributed, are provided on this. The base part 2 of the planet carrier 1 goes with a radius 4th in the planet bolt 3 over, this having a stepped outer jacket surface. This creates a support section with a reduced diameter 5 of the planet bolt 3 pointing towards the base part 2 , so the radius 4th adjacent, by a ring shoulder 6 is limited, the ring shoulder 6 a circular stop surface 7th having.

There is also one on the planet bolt 3 mounted planetary gear 8th on its outer circumference with a toothing 9 as well as on its inner circumference with outer raceways 10 and 11 of a double row tapered roller bearing 12th Mistake. This also has two separate first and second inner rings 13th and 14th as well as these and the outer raceways 10 and 11 assigned rows of rolling elements 15th and 16 on.

Frustoconical rolling elements 17th of the rolling element rows 15th and 16 are on the one hand each in a roller bearing cage 18th and 19th to each other and on their end faces 20th on guide boards 21st and 22nd the inner rings 13th and 14th guided. Furthermore is between the inner rings 13th and 14th a spacer ring 23 arranged. There can also be a single common rolling bearing cage for both rows of rolling elements 15th and 16 be provided, or the two roller bearing cages 18th and 19th are connected to each other.

How further the 1 in connection with the 2 can be seen, is the planet bolt 3 in the area of his from the base part 2 remote end over the axial extension of the tapered roller bearing 12th protrudes radially, so that an annular surface 24 is formed (see in particular 2 ). It is also at an axial distance from the annular surface 24 a circumferential groove 25 intended. On an outer face 26th of the second inner ring 14th there is a support disc 27 that also on the ring surface 24 is supported. The first inner ring 13th of the tapered roller bearing 12th lies with an outer end face 13a on the circular stop surface 7th and thus experiences an axial travel limitation.

As from the enlarged representation after the 2 is found in the circumferential groove 25 a ring 28 whose radially inner area has a chamfer 30th has and consequently as an inclined plane with the circumferential groove 25 cooperates. A side wall 31 the circumferential groove 25 runs parallel to the chamfer 30th so that the chamfer 30th flat on the side wall 31 is applied. Since an inner jacket surface 32 of the ring 28 in this case at a distance from a groove base 33 the circumferential groove 25 runs, the spring-loaded ring can 28 reduce its diameter and move towards the bottom of the groove 33 move. This will make the support disc 27 in contact with the ring surface 24 held and acts as an axial stop for the outer face 26th of the second inner ring 14th .

From the 3 shows that the ring 28 , similar to a piston ring, a transverse slot at one point on its circumference 34 having. The ring should be 28 be designed to be resilient radially inward. Will the planet gear 7th together with the tapered roller bearing 11 and the Support disc 27 on the planet bolts 3 up to the in the 1 and 2 position shown on the planetary pin 3 pushed on, with the corresponding pressing tool the support disc 27 acted upon, the support disc arrives 27 in contact with the ring surface 24 , whereby an axial travel limitation and an increase in force can be seen. Incidentally, this is where the front side lies 13a of the inner ring 13th at the defined stop surface 7th on. Then the ring 28 mounted in the circumferential groove 24 snaps into place. One due to tolerances between the circumferential groove 24 and the ring surface 24 occurring axial play is caused by the ring 28 automatically balanced. The ring slides 28 with its chamfer 29 along the also sloping side wall 30th so that this adjustment function is achieved by means of the inclined plane.

The length of the support section 5 extends to the ring surface 24 . Thus go the width of the support disc 27 and the width of the ring 28 not included in the tolerance calculation for determining the setting range of the tapered roller bearing 12th a. The bevel of the chamfer 29 is chosen so that the system is self-locking and an axial load does not cause the ring to expand 28 leads.

List of reference symbols

1

Planet carrier

2

Base part of 1

3

Planet bolt

4th

Radius from 3

5

Support section of 3

6

Ring shoulder

7th

circular contact surface for 13th

8th

Planetary gear

9

Interlocking

10

Outside career

11

Outside career

12th

Tapered roller bearings

13th

first inner ring

13a

outer face of 13th

14th

second inner ring

15th

Rolling element series

16

Rolling element series

17th

Rolling elements

18th

Rolling bearing cage

19th

Rolling bearing cage

20th

Face of 17th

21st

Guide board

22nd

Guide board

23

Spacer ring

24

Ring area of 3

25

Circumferential groove of 3

26th

outer face of 14th

27

Support disc

28

ring

30th

Chamfering of 28

31

Sidewall of 25

32

Inner surface of 28

33

Groove base from 25

34

Slot from 28

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102015216849 A1 [0007, 0016]
• DE 1813409 A [0009]
• DE 102009032698 A1 [0010]

Claims (9)

Bearing of a planet gear (8) on a planet pin (3) connected to a planet carrier (1) with a double-row rolling bearing (12), the rolling element rows (15 and 16) of which are provided with inclined rolling elements (17) in an O-arrangement to accommodate both radial as well as axial forces and have separate inner rings (13 and 14) guided on a support section (5) of the planetary pin (3), both outer races (10 and 11) of the roller bearing (12) being formed on a common component and wherein a the first inner ring (13) rests by means of its outer end face (13a) on an annular shoulder (6) formed on the planet pin (3) and a second inner ring (14) is supported on its outer end face (26) in the axial direction on the planet pin (3), characterized in that the planet bolt (3) for the axial support of the outer end face (26) of the second inner ring (14) at an end of the support section facing away from the annular shoulder (6) it (5) is reduced in diameter in a step-like manner to form an annular surface (24), with a supporting disc (27) resting both on the outer end face (26) of the second inner ring (14) and on the annular surface (24) and protruding radially above it. is supported in a self-adjusting manner on a part of the planetary pin (3) protruding axially beyond the support section (5). Storage of a planetary gear after Claim 1 , characterized in that the self-adjusting support is designed as a radially inwardly resiliently pretensioned ring (28) engaging with radial and axial play in a circumferential groove (25) of the planetary pin (3), one end face of the ring (28) , which faces away from the outer end face (26) of the second inner ring (14), runs at an acute angle to its transverse plane. Storage of a planetary gear after Claim 1 , characterized in that the end face of the ring (28) running at an acute angle is guided on a parallel side wall (31) of the circumferential groove (25). Storage of a planetary gear after Claim 1 , characterized in that the roller bearing is designed as a double-row tapered roller bearing (12). Storage of a planetary gear after Claim 1 , characterized in that the roller bearing is designed as a double-row tapered roller bearing. Storage of a planetary gear after Claim 1 , characterized in that the roller bearing is designed as a double-row angular contact ball bearing. Storage of a planetary gear after Claim 1 , characterized in that the rolling elements (17) of the two rows of rolling bearings (15 and 16) are guided in at least one rolling bearing cage (18, 19). Storage of a planetary gear after Claim 4 , characterized in that the outer raceways (10 and 11) of the double-row tapered roller bearing (17) are formed in an inner circumferential surface of the planetary gear (8). Method for assembling a double-row tapered roller bearing (12) with inclined rolling elements (17) on a planetary pin (3), the tapered roller bearing (12) having separate inner rings (5) guided on a supporting section (5) of the planetary pin (3). 13 and 14) and both outer raceways (10 and 11) of the tapered roller bearing (12) are formed on a common component and, in the assembled state, a first inner ring (13) by means of its outer end face (13a) on an annular shoulder formed on the planetary pin (3) (6) and a second inner ring (14) is supported on its outer end face (26) in the axial direction on the planet bolt (3), characterized in that the tapered roller bearing (12) together with one on the outer end face (26) of the second Inner ring (14) adjacent support disc (27) is inserted into the planet gear (8), that this unit is then pushed onto the support section (5) by means of a device, until the support disc (27) rests against an annular surface (24) formed at the end of the support section (5), and that then a ring (28) provided radially on the inside with a chamfer (30) and with a flat surface on the end face on the support disc (27 ) adjacent, is inserted into a circumferential groove (25) of the planetary pin.

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