DE3145470A1 - "PULLEY GEARBOX" - Google Patents

Description

Pulley transmission

The invention relates to a pulley drive with pulleys that run over one another and are stacked one on top of the other Blocks existing V-belts, which blocks work with pressure and guided or held by one or more belts will.

Such a pulley transmission generally has a variable transmission ratio. This is why the inner surface of the side flanges of each pulley is tapered. The side flanges of each pulley are in axial direction in relation to one another towards and away from one another. The blocks have a trapezoidal shape Shape that is complementary to the surfaces of the side flanges of the pulleys. Thus, the blocks rise as they approach or the mutual removal of the side flanges of the pulleys up in the radial direction along the side flanges ■ or down. You do not lose contact with them, this, with a variable transmission ratio during operation, in relation to the mean radii according to which the blocks run over both pulleys.

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Bank details: Boyer. Vereinibank MOnchen, Account 620404 (SLZ 700 202 70)

Postal checking account! Munich 27044-802 (BLZ 70010080) (only PA DIpl.-Ing.S. Staeger)

3H5470

• In general, the blocks are made of sheet iron and the Belts made of steel. The fixture assembly is lubricated.

The present invention is based on the object of creating a pulley transmission of the type mentioned, whose assembly conditions and function are improved and which works without lubrication.

According to the invention, the task with .einem transmission is the mentioned type solved in that the blocks are made of sintered metal.

Thanks to this training, the coefficient of friction in relation to the side flanges of the pulleys are significantly enlarged. This is how the contact conditions of the drive are between the blocks and the side flanges and the risk of the blocks slipping in the circumferential direction With respect to the side flanges of the pulleys considerably reduced, which allows an improved transmission. In in the same way, the necessary axial pressure between the flanges is reduced.

Advantageously, at least some of the blocks are made of iron-based sintered metal and have the following weight composition on:

Iron: 80% until 94.5% Copper or molyb
dendisulfite: 0.5% until 5% Nickel: 1 % until 5% Graphite: 3% until' 10%

Coke: 0% to 10%

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3Η5470

With such a composition, the blocks have made of iron-based sintered metal have a coefficient of friction in the range of 0.5 with respect to the side flanges of the Pulleys on instead of 0.3 for sheet iron blocks. '

It is favorable if at least some of the sintered metal blocks have a bonze base and the following composition exhibit:

Copper: 80% to 92%

Tin; 4% to 10%

Graphite: 3% to 10%

Coke: 0% to 5%

Such blocks made of sintered metal based on bronze have a coefficient of friction in the range of 0.2 and are used at the same time as the iron-based sintered metal blocks, but in fewer numbers than the latter and distributed between them.

For example, it is advantageous if one block made of sintered metal on a bronze basis on nine blocks made of sintered metal iron-based is provided. .

Thanks to this arrangement, excellent drive conditions are obtained with a reduction in the risk of slipping.

An advantageous embodiment is that blocks made of sintered metal are provided which are anisotropic with a coefficient of friction on the pulleys, which is much larger in the circumferential direction F1 than in radial direction F 2.

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These anisotropic blocks made of sintered metal have
the following weight composition:

iron until 43 Steel wool until 80 graphite until 20th Molybdenum disulfite until 5 Coke: until '7 Nickel: until 5 : 0% : 50% 5% 1 % 0% 1 %

Because of this design, one receives excellent

Drive contact between the blocks and each belt ■ '

washer in the circumferential direction and at the same time protruding

outstanding change conditions in relation to a change '

of the gear ratio because the blocks are light.

can slide in the radial direction in the pulleys.

Such an anisotropic property results
from the fact that those in the formation of the sintered blocks
provided steel wool is arranged in planes perpendicular to the contact surface of the blocks with 'the flanges, but never in the transverse direction, which creates a kind of' · Γ .division, 'which the coefficient of friction in circumferential. "'direction increased and reduced in the radial direction. |

According to a further advantageous embodiment, it is provided that '' |

that the guide band or bands of the blocks made of aramid fibers ·. [

exist, such as "KEVLAR", where these with an I

elastomeric material can be coated, such as rubber. | The rubber absorbs the relative movements between the
Blocks and the belt and is advantageously used "

because the V-belt is operated without lubrication. "■ |

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The "KEVLAR" fibers have a tensile strength which is three times greater than that of ordinary steels and has a much greater bending capacity. The result of these properties is that they facilitate the rolling of the blocks in the pulleys, in particular during the variation of the transmission ratio _f . Due to the given greater elongation of "KEVLAR" compared to that of steel, it is possible to compress the blocks much more strongly 'which facilitates the assembly of the arrangement, as well as the readjustment of the play during operation of the gearbox.

The two aspects of the invention shown above are preferably combined with one another, and the transmission according to the invention is characterized in that the blocks are made of sintered metal and that or the guide bands are made of aramid fibers, such as "KEVLAR", which guide bands -can be coated with the elastomeric material, such as! Example rubber. "ι

Exemplary embodiments of the invention are explained in more detail below with reference to the drawing. Show it:

Figure 1 is a schematic perspective view of a belt drive according to the invention,

Figure 2 is an enlarged view of a cross section of the belt between the side flanges a pulley,

FIG. 3 a sectional view along the line III-III in Figure 2,

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FIG. 4 an enlarged cross section through a guide band of the blocks,

Figure 5 is a perspective partial view of an embodiment a block with aniso-. tropical properties, with a greater coefficient of friction in the circumferential direction than in the radial direction, which is due to a ■ distribution of steel wool fibers in the Planes parallel to the surface of the blocks

Figure 6 is a schematic representation of a plane,

from which it can be seen that the fibers are completely in-plane and not run across this.

The embodiment shown in Figures 1 to 4 relates to an application as a non-limiting example '' the invention in a transmission with a variable transmission ratio, consisting of a V-belt 10 and pulleys 11 and 12.

Of the. V-belt 10 runs over pulleys 11 and 12 and consists of blocks 13 arranged next to one another in layers, which work with pressure and which by means of a or a plurality of belts 14 (in the exemplary embodiment shown there are two belts) are guided.

Each friction disk 11 and 12 has two side flanges 15, which can be moved apart or together again in relation to one another (arrows F, FIG. 1). The inside surface of each side flange is conical. Each block 13 has a trapezoidal shape with inclined support surfaces 17, the angle of which with the conicity

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of the inner surfaces 16 of the side flanges 15 corresponds.

When the side flanges 15 of a pulley are attached to each other are approximated, the blocks 13 move radially along the flange 15 outwards and run on a larger one Radius. Conversely, when the flanges 15 are moved away from each other, the blocks 13 rise along the side flanges down and run on a smaller radius.

When the flanges 15 of the pulley 11 move together are, while the flanges 15 of the pulley 12 moved apart they cause a change in the transmission ratio in a given sense. In the reverse In the opposite case, the transfer ratio changes in the opposite sense.

The blocks 13 are made of sintered metal.

Nine out of ten blocks 13 made of sintered metal have an iron, basis and have the following weight composition:

Iron: 80% to 94.5%

Copper or
Molybdenum disul-
fit: 0, 5% to 5 5 Nickel: 1 % until 10 Graphite. : 3 % until 10 Coke: 0 % until

For the sintering of these iron-based sintered metal blocks, a powder is compressed, which is made from the above

constituents, under a pressure of 2 to 8 t per cm

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• β * a · ΐ »» ( _T.

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The compression is advantageously carried out by means of a press, which has a floating jacket die and has an ejector stamp provided opposite a pressure stamp. The compression is done in such a way that compression is carried out on both sides in order to promote an even setting of the blank obtained in this way.

This pressed blank is then exposed to a temperature of 1000 to 1100 ° C. in an oven.

After being fired in the furnace, the sintered blocks are subjected to additional compression.

These iron-based sintered metal blocks have a coefficient of friction of approx. 0.5 in relation to the side flanges.

It should be noted that these blocks are less inclined to seize, which is due to the graphite, and are also wear-resistant, which is due to the Konks, and that they are a due to the nickel have excellent tensile strength. The job of copper or molybdenum disulfite is to make things easier the sintering process. . .

A sintered block of ten blocks is based on bronze and j

has the following weight composition:

Copper: 80% to 92%

Tin: 4% to 10%

Graphite: 3% to 10% '

Coke: 0% to 5%. f

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The sintering takes place analogously to the conditions as above has been described for the iron-based sintered metal blocks, however, the firing occurs in the furnace in a temperature range between 700 to 800 ° C instead of 1000 to 1100 ° C for the sintered ones Iron-based blocks.

These bronze-based sintered metal blocks have a coefficient of friction in the range of 0.2 with respect to the Side flanges 15 on. The arrangement of the sintered metal blocks 13, consisting of iron-based ones and bronze-based ones, the latter between the blocks are distributed on an iron basis, enables excellent performance.

Preferably not all blocks 13 have the same dimensions, certain of them, denoted by 13 A in FIG. 3, have a lower strength than the others Blocks 13. This facilitates the unwinding of the V-belt in the pulleys 11 and 12 and improves the operating behavior while changing the gear ratio.

The bands 14 for guiding the blocks 13 are made of aramid fibers, such as "KEVLAR" (Figure 4), which is coated with an elastomeric material 19 such as rubber are.

The "KEVLAR" has the following characteristics:

Density: 1.5

Tear resistance- ₂

capacity: 300 kg per mm

Elongation at break: 4%

Elastic

modulus of efficiency: 13000 kg per mm

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These characteristics are for those in question Uses better than those of steel, which has the following characteristics:

Density ': 7.5

Tear strength: 100 kg per mm

Stretching up to
Elastic limit: 0.5%

Modulus of elasticity: 20000 kg per mm

The guide bands 14, which consist of "KEVLAR" fibers 18 and are sheathed with rubber 19, thus have performances which are considerably higher than those of iron bands.

In particular, the juxtaposition of the blocks 13 no difficulties in assembling the blocks on the belts 14 as a result, this is due to the strong possible stretching of this Bands 14 (4% instead of 0.5%).

"You don't notice any wear and tear during operation or wear and tear, especially between the. Blocks 13 and the straps 14, leaving a distance between each Avoids positions when the blocks 13 come into contact with the pulleys 11 and 12. Be that way no additional tensile stresses are exerted on the bands 14. Furthermore, you don't notice any "beard phenomenon" between the blocks 13. There is practically no risk of seizure, which enables any Avoid lubrication of the device. In addition, the transmission is very quiet.

Furthermore, it should be noted that in the invention the weight of the gear 13 blocks and de _n bands of "KEVLAR" 14 comprised of the sintered V-belt 10 is less

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is as that of a V-belt, which consists of sheet iron blocks and steel strips, which makes it possible is to reduce the tensile stresses caused by centrifugal force.

In a variant (FIGS. 5 and 6) the arrangement is the same as that described above with reference to FIGS. 1 to 4 has been described, however, each sintered metal block labeled 13 'is anisotropic in this embodiment and has a coefficient of friction on the pulleys that is significantly greater in a circumferential direction (arrow F1) than in a radial direction (arrow F 2). . ·

For this purpose the ■ sintered metal block has 13 steel wool fibers on (Figure 6), which are arranged in perpendicular to the friction plane of the block 13 'extending planes P and the do not extend transversely with respect to these planes P.

A kind of split thus takes place in the block 13 ' along the planes P. In the direction of F 1, the block 13 ' . successively a multitude of intermediate surfaces, which the Increase the coefficient of friction F1 in the circumferential direction, while the coefficient of friction F2 is reduced in the radial direction. To hold the thought, it is the coefficient of friction F1 approx. 0.5, which enables excellent drive ratios for the 13 'with the pulleys in the circumferential direction while in a radial direction the coefficient of friction F2 is in the range of 0.2, which allows easy radial sliding of the

Exchange
Blocks 13 ^{l allowed} during the gear ratio in relation to the pulleys. The anisotropic blocks 13 'made of sintered metal preferably have the following weight composition:

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iron

Steel wool graphite · molybdenum disulfite coke

-Nickel

O% to 43%

50% to 80%

5% to 20%

• 1% to 5%

0% to 7%

1% to 5%

The sintering is carried out under analogous conditions as described above. The anisotropy results from pastillation in the press, which for this purpose aligns the fibers of the steel wool according to plane P.

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Claims (1)

PATENT CLAIMS (i .) Pulley drive with a V-belt running over pulleys, consisting of blocks stacked against one another, which blocks work with pressure and are guided by at least one belt, characterized in that the blocks (13/13 ') are made of sintered metal. 2. Belt pulley drive with a block that runs over belt pulleys and consists of stacked blocks V-belts, which blocks work with pressure and are guided by at least one belt, characterized in that the band (14) is made of aramid fibers (18), such as "KEVLAR". '· 3. Belt pulley drive with a block that runs over belt pulleys and consists of stacked blocks V-belts, which blocks work with pressure and from min- -2- Bank pre-binding i Bayer. Vertin "bonk Munich, Account" 20404 (BLZ 70020270) · Postal check account ι Munich 27044-802 (BLZ 70010080) (only PA Dlpl.-Ing.S. Staofler) > · »Ft · 3U5470 at least one tape, characterized in that that the blocks (.13, 13 ') made of sintered metal and the band (14) made of aramid fibers (.18), such as "KEVLAR". 4. Pulley transmission according to claim 2 or 3, characterized in that the belt (14) made of aramid fibers (18) is sheathed by an elastomeric material (19) such as rubber. 5. Pulley transmission according to claim 1 or 3, characterized in that at least some of the blocks (13) from Sintered metal have an iron base and the following weight composition: Iron: 80% to 94.5% .Copper or molybdenum 0.5% " 5 disulfite:. 1 % " 5 '■ Nickel: 3% " 10 Graphite: 0% " 10 Coke: ■ 6. Pulley transmission according to claim. Ϊ or 3, thereby • marked that at least some of the blocks (13) from Sintered metal "have a bronze base and the following weight composition: Copper: 80% to 92% Tin: 4% "10% Graphite -: 3% "10% Coke "" "" ": 0%" 5% -3- 7. belt pulley transmission according to claim 1 or 3, characterized characterized in that at least some of the blocks (13) from Sintered metal have an iron base and the following weight composition. Iron ■: 80% until 94 .5% Copper or molybdenum
disulfite: 0.5% ti 5 % Nickel: 1 % Il 5 % Graphite _: 3% 1O % Coke: 0% 10 % 80 p 92 4 pp 10 3 * 10 0 <! 5 S to L Il L Il L 11 while the remaining blocks made of sintered metal have a bronze base and the following weight composition: Copper tin graphite coke 8. pulley transmission according to claim 7, characterized in that that fewer blocks made of sintered metal on a bronze basis are provided than blocks made of sintered metal on an iron basis', and that the former are divided between the latter. 9. pulley transmission according to claim 8, characterized in that that nine blocks made of sintered metal based on iron is assigned to one block made of sintered metal based on bronze. 10. Pulley transmission according to claim 1, characterized in that blocks (13 ') made of sintered metal are provided which are anisotropic _f with a coefficient of friction on the pulleys which is substantially greater in circumferential direction F1 than in radial direction F 2. -4- .11. Pulley transmission according to claim 10, characterized in that that the anisotropic blocks (13 ') made of sintered metal have the following weight composition: iron : 0 \ 43 Steel wool : 50. ί 80 graphite : 5 ί 20th Molybdenum disulfite 1 ί 5 Coke: 0 ΐ 7th nickel 1. ϊ 5 I to I to S to k to * until i to 12. Pulley transmission according to at least one of the claims 1 to 11, characterized in that different blocks (13 A) are less thick than others. -5-