DE1550761A1 - Planetary gear with a sun gear with a particularly low number of teeth - Google Patents

Description

FICHTEL & SACHS AG., Schweinfürt / Main.

Patent and utility model auxiliary application

Planetary gear with a sun gear with particularly low. Number of teeth

The invention relates to a planetary gear with a non-rotatably arranged ring gear, a rotatable sun gear and at least one with a ring gear and a sun gear or several planet gears which are in mesh with a ring gear and / or sun gear and are in one Planet carrier are rotatably mounted, with all wheels having helical teeth.

Such planetary gears are generally built in one stage for the ratio range from * f: 1 or 1: 4 to 12: 1 or 1:12. The implementation of larger ratios requires a generally unacceptable amount of installation space. To achieve a larger gear ratio, it is already known to design planetary gears with a double planetary gear, which increases the construction costs, but the gear can be built in reasonable dimensions up to ratios of 50: 1. Larger gear ratios are not economically achievable with such a transmission (for the state of the art in this context reference is made to the magazine "Maschinen und Werkzeuge", issue 7 ₉ 196t, page 12, and the magazine "Werkstatt und Betrieb", 93, vol 1960, issue 1, page 12, image 2).

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The invention is based on the object of improving the known transmissions, increasing the reduction ratio while using the same installation space to achieve beyond the extent that normally when using a sun gear with a virtual number of teeth of less than 5 is reached, and thus pushing out the achievable step-up ratio or gear with the same translation to make it smaller and / or more sustainable.

This is achieved according to the invention in that the virtual number of teeth of the sun gear is z _v = 5, and that the number of teeth of the ring gear is increased accordingly while reducing or avoiding the positive profile shift necessary for reducing the number of teeth of the sun gear. With such a design, apart from reducing the number of teeth on the sun gear, there is a further possibility of increasing the gear ratio while maintaining the installation space required, or of making the transmission smaller and / or more load-bearing for a given gear ratio.

The execution of the sun gear with a virtual number of teeth

ζ = 5 can, for example, correspond to DAS 1 210 644 ν

take place. Otherwise it is only known to date to use pinions To use such small numbers of teeth in spur gears. Even after publication of the DAS 1 210 644 corresponding French patent 1 372 890 has the professional world in various Publications the above-mentioned limits of the achievable gear ratios in planetary gears as naturally represented. The application of a sun gear with very

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low number of teeth, as proposed by the invention is not obvious for other reasons. In fact, advantages can not be achieved by the fact that in one any planetary gear any wheels with a small number of teeth can be formed. Rather, it requires more ingenuity Selection as expressed in the features of the present invention.

According to the invention, it is advantageous in the case of a positive Profile shift on the sun gear, which is in the order of magnitude x & l (0.88 <χ <l, 03), the number of teeth of the ring gear is around 2 to increase, so that there is an increase in the through the transmission achievable increment according to the translation formula

ζ + 2z + 2
• 12

^{1 s 1+} H

or i =

+ 2z ₉ + 2

gives * This results in a not inconsiderable increase in the ratio without any additional effort.

Another feature of the invention is that the sun gear at the outwardly protruding end, this extension continues with approximately the same outer diameter as the toothing is provided with means for the non-rotatable connection of a V.'elle. In this way, a particularly simple connection of the transmission is achieved in those cases in which the toothing is not

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cut directly to the drive shaft of a motor or the like is.

For planetary gears in which at least one stepped double planetary gear with several teeth is provided and which were previously feasible with translation jumps of up to 50: 1, the object of the invention becomes particularly in connection solved with claim 1 in that the with the ring gear in The meshing of the double planetary gear teeth has a virtual number of teeth of ζ - 5. Through this design is in such transmissions, especially in connection with the measure of claim 1, a significant improvement achieved in terms of achievable translation or installation space, effort and load-bearing capacity, but without the measure to design the sun gear with a particularly small number of teeth, a considerable improvement over the prior art results.

It is advantageous according to the invention to have such a planetary gear to be carried out so that the double planetary gear is in several parts and consists of a shaft on which the teeth are directly connected is cut open with the small number of teeth, which continues to run along its entire length with approximately the same outer diameter and which is designed as a bearing journal at least at one, but preferably at both ends and then onto this shaft the second toothing is put on in the form of a gear · thereby the result is a structurally very simple design with little processing and assembly effort. / '

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According to a further feature of the invention, the planetary gear designed in such a way that the part of the double planetary gear designed as a gear with a larger number of teeth is made of plastic and is sprayed onto the shaft »whereby the run-out of the toothing cut on the shaft becomes non-rotatably at the same time Serves to support the sprayed-on gear. This design makes fastening the second ring gear extremely simple achieved on the shaft by the already existing gear spout to secure the sprayed-on gear against Twist is used.

To determine the axial position of the double planetary gear, is according to a further feature of the invention of the planet carrier with means to prevent displacement for this double planetary gear provided.

It is advantageous to design these means as cover rings, which are pressed onto the end sides of the planetary gear carrier.

The figures show exemplary embodiments of the subject matter of the invention ·

Fig. 1 shows a single-stage planetary gear with a simple planetary gear or planetary gears, in which the sun gear according to the invention is designed with a small number of teeth.

jig, 2 shows a planetary gear with double planetary gear, in which the sun gear u, one of the ring gears of the double planetary gear *

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is carried out according to the invention with a small number of teeth.

The planetary gear according to FIG. 1 is flanged, for example, to a housing cover 9 * The sun gear 1 of the planetary gear is attached via the shoulder 10 in the bore of the drive shaft 11. The sun gear 1 can according to the invention, for example be designed with three teeth. The toothing of one or more planet gears is located with the toothing of the sun gear 3 in engagement. The planet gears 3 can continue with the ring gear 2, which is arranged in the gear housing 7 so that it cannot rotate. The planetary gear carrier 5 carries planetary gear bearing journals ** which rotatably sit the planet gears 3. 6 is the output shaft connected to the planetary gear carrier 5, which at its outer End which is designed as a V-belt pulley 8 carries output member.

In a comparison, this transmission is now to highlight the advantages of a planetary gear according to the Prior art are compared · Such a planetary gear according to the prior art was designed for one According to FIG. 1, for example, previously carried out with the following data:

Maximum gear ratio (due to structural dimensions) i = 12: 1 _f sun gear z ^ = 10

HohXrad z. = 110 d = 110mm. _v

a O;

m = 1

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ORIGINAL INSPECTED

The planetary gear according to the invention is to be designed, for example, with a sun gear with three teeth. In the following table, the size for a given module and a given ratio, the maximum achievable ratio for a given installation space and the maximum achievable module with a given installation space and a given ratio are compared with each other. Case 1 in line 1 shows a planetary gear according to the invention with Z ₁ = 3 designated. Below that the values for the planetary gear according to the prior art are _{plotted with Z 1} = 10 and in the last line for comparison a spur gear with an input pinion of Z ₁ = 3, as is known, for example, from DAS 1 210 6Ut.

example 1 Example 2 Example 3 Size comparison Translation cf. Module compare if Ei = I} i = 12: l with the same construction i = 12: 1; same room u. m = 1 great installation space case 1 new tarpaulin 33 45 mm i = 37.7: 1 m - 3.33 tetr. with Z ₁ = 3 usual tarpaulin 110 0 mm i = 12: 1 m = 1 tenge tr. with Z ₁ = 10 Spur gear 39 χ 36 mm i = 35.7: 1 m = 2.82 with Z ₁ = 3 909881 / (

Compared to the spur gear used for comparison, the transmission according to the invention also has the advantage that the arrangement of several planetary gears intercepts a bending load caused by the overhung arrangement of the pinion can be. In the case of a spur gear, as it is for example in the third line of the table with regard to its fundamental Sizes is shown, this possibility is not applicable and the bending moments that arise must be dimensioned by appropriate shaft dimensions ung added or avoided by an appropriate bearing arrangement.

In addition to the advantages that can best be seen in the numerical example in the table above, a further increase in the ratio can also be achieved with the same installation space. If one chooses a toothing according to French patent specification 1 37 2 890, it follows from this document that for numbers of teeth from 1 to H the necessary positive profile shift χ is approximately = 1 (it is exactly between 0.88 and 1.03 ). Assuming a profile shift of χ = ■ 1 as given, the result is a pitch circle enlargement of 2xm = 2m. The ring gear must have approximately the same profile shift. The pitch circle d of the ring gear becomes a theoretical pitch circle of d + 2xm. This should be explained using an example:

Consider a planetary gear of the type shown in FIG. 1 with a number of teeth on the sun gear z "= 3 and

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a number of teeth on the planet gear ζ = 21

the number of teeth on the ring gear is then ζ = 45

the ratio then results in i = 1+ - = 16: 1

with a module of m = 1, this is the theoretical increase

of d = 2 and thus d itself = 47 mm 0 ο ο

at m = 2 the theoretical increment of the pitch circle is 4 and thus d itself = 94 mm 0.
ο

However, if the theoretical pitch circle is larger by 2 m, for example 47 mm 0, instead of ζ = 45, ζ = 47 without profile shift can also be selected. The same is true of course for another module m accordingly. However, this results in a gear of the same size with the translation

1 = 1 + 1? = 16.65: 1.

According to the proposal of the invention you can consequently for planetary gear the embodiment according to Fig. 1 achieve a translation ratio increase according to the following relationship:

ζ + 2

i =

From this relationship it can be seen without difficulty that the following translation enlargements can be achieved:

At z ^ a ι a translation increase by 2 translation units

ζ = 2 a translation increase by 1 translation unit

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ζ. = 3 a translation increase of 0.65 translation units z. = 4 · a translation increase by 0.5 translation units

In Fig. 2, an embodiment of a planetary gear with double planetary gear is shown. The figure shows a design in which the sun gear 1 and teeth 13 of the double planetary gear are designed with a small number of teeth. Here, too, is a gear flanged to a housing cover 9, wherein the sun gear 1 with a gear 19 of the double planetary gear is in engagement and the ring gear 18 meshes with the teeth 13 of the double planetary gear. The double planetary gear consists of the Shaft 12, on which the toothing 13 is cut directly, and the gear 19 attached to this shaft. The ends of the Shaft 12 are designed as bearing journals 15. The shaft 12 can be rotated in the planetary gear carrier 5 by means of the bearing journals 15 stored, the stop rings 17 to limit the axial mobility of the double planetary gear. The gear 19 of the double planetary gear is made of plastic and is injected directly onto the shaft 12 and counteracts the toothing 13 through the outlet Rotation secured. The ring gear 18 is fastened in the transmission housing 7. The planetary gear carrier 5 is connected to the output shaft 16 .

The following is a numerical example for three design variants of the transmission according to the invention examined the improvement over a transmission according to the prior art.

The transmission according to the prior art should in principle corresponds

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corresponding to Figure 2, but all "gears be equipped with normal numbers of teeth. The translation should

i = 49: 1 (maximum building limit).
Furthermore, should be

the number of teeth of the son wheel z, = 10

the number of teeth of the larger ring gear of the double planetary gear

. Z ₂ = 60

the number of teeth of the smaller ring gear of the double planetary gear

. Z ₃ = 10

and the number of teeth of the ring gear Z ₁₁ = 80 η = 1 is selected as the module.
This results in the maximum Bauraur. from the sub-circles:

Z ₁ + 2z ₂ = 130 ix-! t - ..- ■■ - ..

The execution variant case 2 of the inventive gearbox, that with the. other variants and the above gear, geir.ä. ^ der. State of the art is to be compared, shows a sun gear ζ- with a small number of teeth, while, all other gears ir.it Numbers of teeth are designed according to the known gear. For case 2 is -..-..-

The embodiment variant case 3 provides that the second ring gear of the double planetary gear with a small number of teeth

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is, while all other gears number of teeth according to the known Have gear. For this variant, case 3,

Z ₃ = 3.

In the execution variant case U of the transmission according to the invention Both the sun gear 1 and the second ring gear 13 of the double planetary gear (see Figure 2) are designed with a small number of teeth. The other wheels, namely 19 and 18, have numbers of teeth that correspond to the known gear. So there are the deviating ones Number of teeth in case 4:

z ^ - 3 and
Z ₃ = 3

If these values are met, the following comparison with regard to installation space with the same module and the same gear ratio is more possible Ratio increase with the same installation space and the same module; and possible module enlargement with the same installation space and with same translation.

The following results from the installation space comparison:

13 -

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Case 2

Planetary gear

Case 3

Case 4

Given

τ. = 3; m = 1} Z ₁ = IO; m = 1;

ζ = 3; m = 1;

Z 3 = 10 45 X = I . 32 · IU 3 ·

z ₃ = 3

12.. ns 10 "T

18th 24

= 49: 1 = 49: 1

= 49: 1

Installation space

(3 + 2.32) .1 = 67 (10 + 2.32) .1 = 74

(3 + 2.18). 1 = 39

reduction

From 130 to 67 mm From 130 to 74 mm

From 130 to

39 mm

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- IH - The ratio comparison results in:

plan
Case 2 etengetrie
Case 3 be
Case H Given 130 mm installation space
m = 1
Z ₁ = S; Z ₃ = OK 130 mm
m = 1
Z ₁ = IO; z ₃ = 3 130 mm
m = 1
_V 3; z ₃ = 3 ^Z 2
with magnification
d.Number of teeth
corresp.
profile
verse eh.
Case 2
and H 63 60 63 ^Z H
with
correction
d. teeth
number
corresp.
Construction
knife 76 73 69 i = l +
v \ = 160.6 t 1
opposite U9 * 1 = l + £ 6. H
10 3
s 147 j I
compared to 49: 1 = HSH t 1
opposite ^ 9 Jl
"I. ² I ^Z 3

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The comparison with regard to module ^{enlargement results in the following values: öC}

Plan
Case 2 ete η gear
Case 3 Z ₁ = 3; z, = 10;
z ₂ = 32 z ₂ = 32 130 be
Case «♦ Given 130 mm; i = H9 130 ι Ιο + δ.35 ")
= 1.75
compared to m = l (3 + 2.32 i
= 1.95
compared to m = l z ₂ = 18 module
I. m- ¹³ ° t3 + i, 18y
= 3.33
compared to m = l

From these overviews, the large technical one is particularly good Progress can be seen which is achieved by the invention. There is already a considerable improvement in the transmission type according to Fig. 2 by the use of a planet gear with a smaller Number of teeth achieved as a ring gear on the double planetary gear. This advantage can be increased by using a sun gear with a small number of teeth and reaches its maximum with a combination both measures.

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Claims (1)

Claims ί 1.1 Planetary gear with a non-rotatably arranged ring gear, a rotatable sun gear and at least one with ring and sun gear or * several planet gears in mesh with ring and / or sun gear, which are rotatably mounted in a planet gear carrier, whereby all gears have helical gears , characterized in that the virtual number of teeth of the sun gear is ζ = 5, and that the number of teeth of the ring gear (2) is increased accordingly while reducing or avoiding the positive profile shift necessary when reducing the number of teeth of the sun gear (1). 2. Planetary gear according to claim 1 and 2, characterized in that that with a positive profile shift on the sun gear (1) in the order of magnitude χ «Ί (0.88 <x <1.03) the number of teeth of the ring gear (2) is increased by 2, so that an increase in the increment that can be achieved by the gearbox according to the translation formula Z ₁ + 2z «+ 2 i - i ₊ -i—— i ^z l or i = Zj + 2z ₂ + 2 1+ results. 3. Planetary gear according to claim 1, characterized in that the sun gear (1) at the outwardly protruding end continues with approximately the same outer diameter as the toothing and _ 2 - 909881/0668 .., _ \ y: ^ r \ zrZ7. C -.7 £ 1 paragraph 2 MM sentence 3 this extension (10) with means for non-rotatable connection of a Shaft is provided. 4. Planetary gear, in particular according to claim 1, in which at least a stepped one with several teeth Double planetary gear is provided, one toothing of which meshes with the sun gear and the other toothing of which engages is in engagement with the ring gear, characterized in that the toothing which is in engagement with the ring gear (18) (13) of the double planetary gear (19, 12, 13) has a virtual number of teeth of ζ = 5 5. Planetary gear according to claim 5, characterized in that the double planetary gear (19, 12, 13) is in several parts and consists of a shaft (12) on which the toothing is directly attached (13) is cut open with the small number of teeth, which continue to have approximately the same outer diameter over their entire length is designed and at least one, but preferably at both ends as a bearing pin (15) and on this Shaft (12) then the second toothing in the form of a toothed wheel des (19) is attached. 6. Planetary gear according to claim 5 and 6, characterized in that that the part of the double planetary gear (19, 12, 13) designed as a gear (19) with a larger number of teeth is made of plastic and is sprayed onto the shaft (12), the outlet the toothing (13) cut on the shaft (12) " ³ " 909881/0888 at the same time serves to support the sprayed-on gearwheel (19) in a non-rotatable manner. 7, planetary gear according to claim 5 to 7, characterized in that that the planetary gear carrier (5) with means (17) to prevent displacement for the double planetary gear (19, 12, 13) is provided. 8. Planetary gear according to claim 8, characterized in that that these means consist of cover rings (17) which are pressed onto the end sides of the planetary gear carrier (5). 27. 1. 69 909881/066 Blank page