JP4286509B2 - Planetary gear type transmission - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a planetary gear type transmission comprising a sun gear driven by a drive engine, an internal gear arranged in a housing, and a group of planetary gears supported by a planetary gear carrier.
[0002]
[Prior art]
A transmission of this kind is disclosed in German Offenlegungsschrift 19720255. The transmission is characterized by high efficiency, low rotational play, high transmission fidelity and low noise generation. Large transmission ratios can be obtained at high power densities and very short axial structure lengths.
[0003]
[Patent Document 1]
German Patent Application Publication No. 19720255 Specification
[Problems to be solved by the invention]
However, the transmission shown in the above-mentioned German Patent Application No. 1720255 is particularly expensive in that the planetary gear carrier and the housing are expensive and many parts have to be adjusted for their play during assembly. Therefore, its production and assembly are very expensive.
[0005]
SUMMARY OF THE INVENTION An object of the present invention is to provide a transmission that can be manufactured at low cost with a large transmission ratio, a short axial structure length, and a small rotational play.
[0006]
[Means for Solving the Problems]
This task comprises a sun gear driven by a drive engine, an internal gear arranged in a housing, a group of first planetary gears, and a group of second planetary gears, all of these planetary gears being common The number of second planetary gears corresponds to half of the number of first planetary gears, and each second planetary gear is formed as a stepped planetary gear having a small gear and a large gear. A planetary gear having a configuration in which the large gear of the stepped planetary gear meshes with the sun gear, and simultaneously the small gear of the stepped planetary gear meshes with a pair of adjacent first planetary gears, and the first planetary gear meshes with the inner gear. A planetary gear type transmission having an opening on the planetary gear carrier drive engine side in which a large gear of a stepped planetary gear is inserted in the axial direction through the opening during assembly; Solved by
[0007]
In this solution, the planetary gear carrier has an opening on the drive engine side, and when assembled, the large gear of the stepped planetary gear is inserted in the axial direction through the opening. Thereby, the planetary gear carrier can be formed at low cost. The planetary gear carrier is equipped only from one side and therefore has a closed end face on the opposite side.
[0008]
The opening in the planetary gear carrier is preferably formed as a central hole with a diameter larger than the diameter of the tip circle of the large gear of the stepped planetary gear. Preferably, a receiving part for the large gear of the stepped planetary gear is provided in the planetary gear carrier, the receiving part being open towards the opening or the central hole. That is, the individual stepped planetary gears are sequentially inserted through the central hole and then moved radially outward to the receiving portion and placed in their operating positions. There is an endless ring around the opening, which greatly increases the strength of the planetary gear carrier.
[0009]
In connection with the present invention, a sun gear driven by a drive engine, an internal gear arranged in a housing, a group of first planetary gears and a group of second planetary gears, all of these planets The gears are supported by a common planetary gear carrier, the number of second planetary gears corresponds to half the number of first planetary gears, and each second planetary gear is formed as a stepped planetary gear having a small gear and a large gear. The large gear of the stepped planetary gear meshes with the sun gear, and simultaneously the small gear of the stepped planetary gear meshes with a pair of adjacent first planetary gears, and the first planetary gear meshes with the inner gear. in the planetary gear transmission, the first planetary gear and stepped planetary gear, is arranged inside the dedendum circle of the full internal bus gear in the radial direction, also the planetary gear transmission, characterized in that Can be provided .
[0010]
In this transmission , the first planetary gear and the second planetary gear are arranged completely inside the root circle (bottom circle) of the inner gear in the radial direction, so that an extremely simple assembly sequence is achieved. can do. In this assembly sequence, the planetary gear carrier is first fully equipped with a stepped planetary gear and a planetary gear, which are inserted into the housing as a preassembled assembly. For this purpose, the housing preferably has an opening on the end face opposite to the drive engine, through which the planetary gear carrier, into which the planetary gear has been previously installed, is inserted. Thereby, the planetary gear carrier closes the transmission to the outside on the side of the housing where the transmission is inserted.
[0011]
In an advantageous embodiment of this transmission , the housing has a cylindrical jacket part, which is provided with an inner gear or is machined with an inner gear. The cylindrical jacket portion is closed on the drive engine side by a housing cover. That is, the housing is closed on one side by the end face of the planetary gear carrier and on the other side by the housing cover. This allows the housing to approach the bearing installation from both sides. Thus, the planetary gear carrier can be supported in the cylindrical jacket part by two bearings. In that case, the meshing surfaces of the first planetary gear and the second planetary gear are arranged between the bearings in the axial direction. That is, since a wide bearing base is formed, a large lateral load and tilt load can be received in the planetary gear carrier that forms the driven portion.
[0012]
In another advantageous embodiment of the transmission , the housing cover has an inwardly facing central projection, which at least partially occupies the same axial structural space as the planetary gear, A sun gear bearing and / or shaft seal packing ring is disposed therein. This makes the best use of the free structure space in the region of the central opening of the planetary gear carrier. The sun gear bearing or shaft seal packing ring provided at this point has a small diameter, so that, despite the large sun gear rotation speed, only a very small sliding speed or rolling speed is produced, resulting in a small friction loss. .
[0013]
When a large transmission ratio is required, the structural space within the hollow chamber surrounded by the planetary gear carrier and open on one side is the front gear stage provided between the sun gear and the drive engine in the drive system. It applies to. In a transmission having a very large transmission ratio and a compact structure, the sun gear is firmly coupled to the planetary gear carrier of the front gear stage, the planetary gear of the front gear stage is arranged on the planetary gear carrier, and these planetary gears are It is obtained by always meshing with an internal gear attached to the planetary gear carrier of the main gear stage and a central drive gear driven by a drive engine.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0015]
In FIG. 1, reference numeral 2 denotes a drive shaft, and the drive shaft 2 has a receiving portion for an output shaft of a drive engine (not shown). The sun gear 4 is firmly connected to the drive shaft 2 by meshing teeth 6. The transmission housing includes a cylindrical outer cover portion 8 and an engine-side housing cover 10. An inner gear 12 is machined in the cylindrical jacket portion 8. The planetary gear carrier 14 forms a driven part. A group of first planetary gears 16 and a group of second planetary gears 18 are supported on the planetary gear carrier 14. The planetary gear of the second planetary gear 18 is formed as a stepped planetary gear.
[0016]
1 is taken along the line II in FIG. The stepped planetary gears 18 located on both sides are meshed with the sun gear 4 by the large gears 20 (see FIG. 2). The small gear 22 of the stepped planetary gear 18 meshes with a pair of adjacent first planetary gears 16 (only one is shown in FIG. 1). The stepped planetary gear 18 has a large gear 20 disposed on the side opposite to the drive engine. The meshing surface of the sun gear 4 and the large gear 20 is located on the side opposite to the drive engine with respect to the meshing surface of the internal gear 12. A radial shaft seal packing ring 42 seals the transmission housing from the outside. Further, the first planetary gear 16 meshes with the inner gear 12 (see FIG. 3).
[0017]
In this transmission, the input power is distributed to the two meshing portions in each of the sun gear 4 and each small gear 22 of the stepped planetary gear 18. Thereby, as the transmitted torque increases according to the gear ratio, more and more meshing teeth are involved in torque transmission. The sun gear 4 and the small gear 22 of the stepped planetary gear 18 are supported so as to be slightly movable in the radial direction. As a result, the sun gear 4 and the small gear 22 naturally find their radial positions at the meshing portions with the large gear 20 or the first planetary gear 16. That is, the small gear of the stepped planetary gear is actually suspended and supported at the meshing portion with the first planetary gear group. This ensures a very uniform load distribution on the individual meshing teeth.
[0018]
According to the present invention, the planetary gear carrier 14 has an opening formed as a central hole with a diameter closely matching the diameter of the large gear 20 inside the rotating ring 24 on the drive engine side. Accordingly, the stepped planetary gear 18 is inserted through this opening from this side of the planetary gear carrier during assembly. As a result, the driven side of the planetary gear carrier 14 can be a sealed side surface that closes the transmission toward the outside.
[0019]
Further, the first planetary gear 16 and the stepped planetary gear 18 having a through-tooth (durchgehende Verzahung) are disposed completely inside the root circle of the internal gear 12 in the radial direction. This ensures a simple assembly process. First, the planetary gear carrier 14 is equipped with a stepped planetary gear 18 and a planetary gear 16 and is inserted into the housings 8 and 10 as a preassembled unit. For this purpose, the housing has an opening on the end surface opposite to the drive engine.
[0020]
The transmission is closed on one side by a planetary gear carrier 14 and on the drive engine side by a housing cover 10. With this structure, planetary gear carrier bearings 26 and 28 are provided between the planetary gear carrier 14 and the cylindrical jacket portion 8 on both sides of the meshing surfaces of the first planetary gear 16 and the second planetary gear 18, respectively. it can. These bearings 26 and 28 are formed as tapered roller bearings (or angular bearings) and are arranged in an O-shaped bearing structure. As a result, a large bearing base is generated, and a large lateral load and inclined load are received in the planetary gear carrier 14 forming the driven portion.
[0021]
The housing cover 10 has a central protrusion 30 facing inward, and the central protrusion 30 is stepped in multiple stages. The central protrusion 30 extends into the axial space occupied by the planetary gear and supports the sun gear bearing 32 and the shaft seal packing ring 34.
[0022]
One side of the stepped planetary gear 18 is supported by a planetary gear bearing 36, and this bearing 36 is placed on a planetary gear support bolt 38. The planetary gear bearing 36 is formed as a needle bearing and is disposed in the meshing range of the large gear 20 in the axial direction. This cantilevered support produces a constant tilting of the stepped planetary gear, so that the small gear 22 can move slightly in the radial direction and can be displaced radially in engagement with each pair of planetary gears 16. During assembly, the stepped planetary gear 18 is first placed in its operating position through a central hole on the drive engine side in the planetary gear carrier. In the next step, the planetary gear support bolt 38 is inserted from the outside through the through hole 40 in the planetary gear carrier 14. The planetary gear support bolt 38 is press-fitted into the planetary gear carrier 14, whereby the planetary gear support bolt 38 closes the planetary gear carrier 14 in an airtight manner to the outside.
[0023]
In FIG. 4, four successive assembly steps of the stepped planetary gear 18 to the planetary gear carrier 14 are shown. First the first stepped planetary gear is inserted through the opening in the planetary gear carrier and then moved radially outward (see the lower part of FIG. 4 (a)), after which the second stepped planetary gear is inserted through the opening into the planet. Placed in gear carrier 14. As shown in FIG. 4 (b), since the first stepped planetary gear that is put in first is tilted outward, the second stepped planetary gear as shown in FIGS. 4 (c) and 4 (d) The stepped planetary gear is similarly placed in its operating position. Only when the stepped planetary gear is in its operating position, the planetary gear support bolt 38 is press-fitted through the end face of the planetary gear carrier 14 (see FIG. 1). This assembly sequence makes it possible to utilize the structural space very well.
[0024]
In the embodiment shown in FIG. 5, the same reference numerals as in FIG. A front gear stage is provided between the sun gear 4 in the drive system and the input shaft 2 on the drive engine (not shown) side in the hollow chamber 44 closed by the planetary gear carrier and opened on one side. This front gear stage has a planetary gear carrier 46. The planetary gear carrier 46 is rigidly connected to the sun gear 4, and a plurality of planetary gears 47 at the previous shift stage are disposed thereon. These planetary gears 47 are always meshed with an internal gear 48 firmly coupled to the planetary gear carrier 14 of the main gear stage and a central drive gear 50 coupled to the drive shaft 2. The combined front shift stages 46, 47, 50 enable a very large total transmission ratio in a compact structure.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of an embodiment of a transmission according to the present invention.
2 is a cross-sectional view taken through a meshing surface of a large gear of the stepped planetary gear shown in FIG. 1;
3 is a cross-sectional view through the meshing surface of a small gear of the stepped planetary gear shown in FIG.
FIG. 4 is an explanatory view showing the steps of assembling a stepped planetary gear to the planetary gear carrier in the order of (a) to (d).
FIG. 5 is a longitudinal sectional view of an embodiment including a front shift stage of a planetary gear type transmission according to the present invention.
[Explanation of symbols]
2 Drive shaft 4 Sun gear 6 Engagement tooth 8 Housing part 10 Housing housing cover 12 Internal gear 14 Planetary gear carrier 16 Planetary gear 18 Stepped planetary gear 20 Large gear 22 Small gear 24 Ring 26 Bearing 28 Bearing 30 Projection 32 Sun gear Bearing 34 Shaft sealing packing ring 36 Bearing 38 Planetary gear support bolt 40 Through hole 42 Shaft sealing packing ring 44 Hollow chamber 46 Planetary gear carrier 47 Planetary gear 48 Inner gear 50 Gear

Claims (6)

A sun gear (4) driven by a drive engine, an internal gear (12) disposed in the housing (8, 10), a group of first planetary gears (16), and a second planetary gear (18) With a group of
All these planetary gears are supported by a common planetary gear carrier (14), the number of second planetary gears (18) corresponds to half of the number of first planetary gears (16), and each second planetary gear (18 ) Is formed as a stepped planetary gear having a small gear (22) and a large gear (20), and the large gear (20) of the stepped planetary gear meshes with the sun gear (4), and at the same time, a stepped planetary gear. In the planetary gear type transmission in which the small gear (22) is engaged with a pair of adjacent first planetary gears (16) and the first planetary gear (16) is engaged with the inner gear (12).
The planetary gear carrier (14) is provided with a rotating ring (24) on the side of the drive engine , and this rotating ring (24) is a central hole into which the large gear (20) of the stepped planetary gear is inserted in the axial direction during assembly. The diameter of the central hole is larger than the diameter of the tip circle of the large gear (20) of the stepped planetary gear (18),
The planetary gear type transmission, characterized in that the planetary gear carrier (14) further comprises a receiving part for the large gear (20) of the stepped planetary gear that opens towards the central hole . The planetary gear type transmission according to claim 1 , wherein the small gear (22) of the stepped planetary gear (18) is supported in a floating manner in a meshing portion with the first planetary gear (16). Each stepped planetary gear is supported on the planetary gear carrier (14) by means of a bearing (36) arranged in the range of the large gear (20) via a planetary gear support bolt (38). The planetary gear type transmission according to claim 1 or 2. The large gear (20) of each stepped planetary gear (18) has a hole for receiving the bearing (36), the bearing (36) is placed on the planetary gear support bolt (38), and the planetary gear support bolt 4. The planetary gear type transmission according to claim 3, wherein (38) is inserted through a through hole (40) on the end face side of the planetary gear carrier (14). A front gear stage is provided between the sun gear (4) and the drive engine in the drive system, and the front gear stage is at least partially closed by the planetary gear carrier (14) and open on one side. The planetary gear type transmission according to any one of claims 1 to 4 , wherein the planetary gear type transmission is disposed in the inside of the planetary gear. The sun gear (4) is firmly coupled to the planetary gear carrier (46) of the front gear stage, and the planetary gear (47) of the front gear stage is arranged on the planetary gear carrier (46), and these planetary gears (47) and if among annexed to the main gear of the planetary gear carrier (14) wheel (48), according to claim constantly meshed to a central drive gear is driven by the drive motor (50), and wherein the 5 The planetary gear type transmission described.

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