The invention relates to a planetary gear with a planet carrier and planet gears, which mesh by means of teeth with a ring gear on one side and with a sun gear on the other side, wherein the planet gears can rotate on planet gear pins by means of roller bearings and the planet gear pins are held in location holes of the planet gear carrier.
Such planetary gears are sufficiently well known to someone skilled in the art. In the interior of a planet gear set, the so-called sun gear turns on a central shaft. Several gears having teeth that engage in the peripheral teeth of this sun gear are provided, in practice usually three to five, which are designated as planet gears due to their obvious arrangement. And as planets, as they rotate they also move in a circular motion about the sun gear, while they simultaneously turn about their own axis. The shafts of the planet gears are fixed on the planet gear carrier, which receives this rotational movement, that is, likewise in the rotational direction about the central axis. As a third element, the ring gear surrounds the entire formation, in that it engages the planet gears with its internal teeth from the outside. Here, the central axis also represents the center of rotation.
The shafts of the planet gears are also designated as planet gear pins and are fixed in the planet gear carrier in various ways.
According to DE 196 11 605 A1, this is realized in that both the planet gear carrier and also the planet gear pins are provided with radially extending holes, in which attachment screws are inserted. After being screwed in, the screw bodies of these attachment screws are both in the planet gear pin and also in the planet gear carrier, so that the planet gear pins are secured against axial displacement. It is obvious that such a position-fixing device of the planet gear pin is very complicated. First, both in the planet gear carrier and also in the planet gear pin, the location holes are to be formed and provided with a corresponding internal thread. Then, both are set relative to each other in the peripheral direction so that the holes align, before finally, the attachment screws can be inserted.
Another such type of attachment follows from the German Utility Model Application DE 74 181 65 U. This is realized in that first a hoop ring is pushed onto the planet gear pin. The ring is connected to the pin by means of a weld. Then, the planet gear pin is secured by means of a retainer ring, which engages in an annular groove of the collar ring and secures this against axial displacement. Here, it can also be recognized that such an attachment of the planet gear pin in the planet gear carrier is very complicated and costly.
Finally, in DE-OS 25 03 518, another type of attachment of the planet gear pin in a planet gear carrier is described.
Therefore, starting with the disadvantages of the prior state of the art, the invention is based on the objective of reducing expense in the manufacturing or assembly process of a planetary gear through a simpler type of attachment of the planet gear pin in the planet gear carrier.
According to the invention, this problem is solved according to the characterizing portion of Claim 1 in connection with its preamble, such that an axial displacement of the planet gear pin in the planet gear carrier is prevented by an elastically deflectable or deformable retaining element, which, on one hand, engages in a location hole in the planet gear pin and, on the other hand, covers the planet gear pin and planet gear carrier in the radial direction.
It is obvious that such a type of attachment is considerably simplified relative to the prior state of the art, because only one retaining element connecting the planet gear carrier and planet gear pin has to be pushed into the location hole of the planet gear pin. After its elastic expansion or deformation, a secure hold of the two parts to each other is guaranteed.
Other advantageous configurations of the invention are described in the subordinate Claims 2 to 8.
Thus, according to Claim 2, the retaining element has a circular ring-type region extending in the radial direction. Bars extend from this region in the axial direction in the shape of a pipe and are separated from each other in the peripheral direction by axis parallel slots and have locking cams projecting radially outwards at their free ends.
In an advantageous improvement of the invention, according to Claim 3, the circular region of the retaining element should be provided in its center with a passage. This is required if the roller body of the planet gear is to be supplied with lubricant via the retaining element and the planet gear pin.
According to Claim 4, this retaining element is produced from a spring steel or from a plastic.
According to Claim 5, a notch is machined into the location hole of the planet gear pin. An annular retaining surface for the locking cams of the retaining element is formed by this notch. In this way, a secure locking connection is formed between the retaining element and the planet gear pin.
Another improvement of the solution according to the invention is described in Claim 6. According to this claim, several retaining elements are connected to each other in the peripheral direction by a radially extending circular ring, from which they extend in the axial direction, so that a compound retaining element is formed. This is especially advantageous, because, for example, in a planetary gear with five planet gears, five retaining elements do not have to be handled individually, instead only one.
Another essential improvement of the invention follows from Claim 7. According to this claim, several retaining elements are connected to each other in the peripheral direction by a hollow body that is open towards one side, so that a compound retaining element is formed.
According to Claim 8, this hollow body comprises two radially extending circular rings, which are spaced apart from each other in the axial direction and which are connected at their outer extent by an axially extending back part, wherein there is a passage that extends to the space between the two circular rings in the circular ring which is connected to the retaining elements.
The advantage of this arrangement lies not only in a simple connection of several retaining elements, but it also lies in the fact that this retaining element combined according to the invention can be used simultaneously for improved directed oil guidance in planetary gears. Thus, retention and directed oil guidance functions are combined into one. According to the prior state of the art, the oil guidance function was realized through complicated additional retaining sheets.
The invention is described in more detail using the following embodiments.
Shown are:
a side view of a compound retaining element without an oil guidance function,
a section and a perspective view, respectively, of a compound retaining element with an oil guidance function,
The planet gear carrier 1 shown in
In
The planet gear shown in
If a planetary gear is equipped, for example, with three planet gears 6, then it has proven to be advantageous to connect three individual retaining elements 9 to the circular ring 11, such that these elements are arranged at three peripheral positions spaced apart from each other uniformly and so that they extend from this ring in the axial direction. In this way, a compound retaining element 9a is formed, which simplifies the assembly of the planetary gear with the provided three planet gears. Such a retaining element 9a is shown in
In
Finally, in
Planet gear carrier
1.1 Location hole
2 Side wall
3 Side wall
4 Planet gear pin
5 Bearing
6 Planet gear
7 Teeth
8 Stopping plate
9 Retaining element
9
a Retaining element
9
b Retaining element
9.1 Circular region
9.2 Bar
9.3 Slot
9.4 Locking cam
9.5 Longitudinal axis
9.6 Passage
10 Location hole
10.1 Notch
10.2 Retaining surface
10.3 Radial hole
11 Circular ring
12 Hollow body
12.1 Circular ring
12.2 Circular ring
12.2.1 Passage
12.3 Back part
13 Sun gear
13.1 Teeth
Number | Date | Country | Kind |
---|---|---|---|
103 09 666.3 | Mar 2003 | DE | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
---|---|---|---|---|
PCT/EP04/01651 | 2/20/2004 | WO | 2/9/2006 |