DE2138110A1 - HYDRODYNAMIC CLUTCH, IN PARTICULAR FOR POWER TRANSMISSION IN MOTOR VEHICLES - Google Patents

Description

S QO S f U

Daimler-Benz Aktiengesellschaft Palm

Stuttgart 2i _o

transfer at

The invention relates to "'© iss © fejsSrodysaotaäoeh © Itappl" j g ₉ las particular for ICraftufoertragtmg b a Priisär- and a Sekundärsehal © ₉ d © jr © 5ffi in & Gfasneihen area of Ströüsungskreislaufss about! Semicircular isa © ima "the üb @ rg © h © a um.d in the outer area of the flow output Mreislanf © © over © iss. © ® Area of the shell depth cylindrical.

Hydrodynamic couplings of the type are already known from the applicant (German patent specification i 2 ^ 4 53B) ο These couplings result in normal cast construction ά @ ζκ © r% din®cht © a Kestnlinienverlauf d, * h · the characteristic is isss B © r © I is relatively low slip to damn, n oh little attenuation in a more or less horizontally extending part having a relatively low Anfahreert go · but if there aw a, such a coupling the Flow conditions and / or for the production in die casting or with a polished wall is carried out or made of sheet metal, this results in a highly unpleasant change in the characteristic curve in the range of the low The slip rising steeply © part of the characteristic curve then shoots, instead of the slight attenuation, by a considerable amount above the initial value, then collapses suddenly and only then goes away ßend into the more or less horizontally running Kenalinienteil over. This characteristic curve peak is highly undesirable,

- 2 20 9 8 86/0607 _{0B1GlNÄL INS} PECTEI>

- 2 - Daira 9026/4

because u. & e. Because "the dreaded clutch picking occurs when starting up", the same. disadvantageous effect also occurs with clutches in normal cast design, wQXsn a _o B _e with clutches with a large diameter that between the "blade" is relatively large compared to the flow channel Desi Randfeersieh, see that the influence of the casting roughness on the walls is negligibly small compared to the overall distribution «>

The invention is now the task of the round, the described Avoid disadvantages «So it should be a hydrodynamic © Coupling be struck and was in particular, ab © r not exclusively, for couplings in die-cast or sheet metal Execution in which the dreaded peak in the characteristic curve no longer occurs that the characteristic curve in the Boreich low slip runs as steeply as possible and then into one more or less horizontally running part passes over with a relatively low approach value

In the hydrodynamic clutches mentioned at the outset, this object is achieved according to the invention in that on the secondary shell only in the outer area of the flow circuit do the blades with a set back opposite the shell edge Trip hazards are provided · By the invention Training, the advantage is achieved that even in the above-mentioned embodiments or in the above mentioned cases, the dreaded peak in the characteristic curve is either completely reduced or at least except for one very small vanishing residue is returned. In the region of low slip, b «i runs according to the invention Training the characteristic curve even steeper than with the known Execution, and it then merges into an almost horizontal part, where ·! the approach value - as desired, relative is small. It should be mentioned here, however, that © ine

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3 - Palm 9026/4

simultaneous setback of the bevel dax * shell itself more or less influences the effect sought according to the invention, ie. the shell © oll protrudes with its outer edge at least partially roof-shaped over the recessed stumbling block.

In a preferred embodiment according to the invention, the stumbling edge extends radially to approximately five to fifteen percent of the radial blade length, measured at the blade edges. Furthermore, it is preferred if the setback of the stumbling edge with respect to the outer shell edge in the axial direction is approximately equal to its radial extent.
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It has been found to be particularly advantageous if, according to a further feature of the invention, the stumbling block formed by a bevel of the blade at about 45 degrees is. Another embodiment of the invention proposes that the stumbling block by a substantially rectangular Notching of the blade is formed. Other possibilities are that this notch is a has a circular contour, i.e. is formed in the manner of a quarter or semicircle.

For hydrodynamic couplings with sheet metal blades, J

the effect according to the invention can be improved by the fact that the blades in the area of the trip edge with sharp Edges are provided. This can be done, for example, by over-turning the blades at their front edges in the area of the stumbling block take place.

Details of the invention are shown in the exemplary embodiments Drawing, namely shows:

Figure 1 shows a diagram of the characteristic curve Explanation of the mode of operation of the invention,

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Palm 9026/4

Fig «2 the secondary shell of a preferred embodiment

form of the invention in section and Fig. 3a to d further configurations of the stumbling block.

According to Figure 1, the curve 10 shows the characteristic curve of a known clutch, for example in a die-cast version the disadvantage described. The characteristic increases in the range OK of the low slip, although it rises steeply, but then forms a very high, undesirable peak 10b and then breaks almost suddenly up to the more or less horizontally extending part 10c. This is presumably through to explain a breakdown of the flow as a result of separation phenomena. In contrast, the curve 11 shows the Characteristic curve of the clutch proposed according to the invention * It rises just as steeply in the area of low slip and then goes continuously without the dreaded peak into the horizontally running part, with the approach value 12 increases only insignificantly compared to that of the known clutch

According to FIG. 2, the blades 13 of the secondary shell in the outer region of the flow are bevelled at approximately k5 degrees in relation to the cylindrically extending shell part 15 in order to form a stumbling edge Ik. The shell part I5 thus, to a certain extent, projects over the stumbling edge lk in a roof shape. The radial extension l6 of the stumbling edge Ik counteracts sudden reversal effects in the toroidal flow and thus prevents these detachment phenomena, which would lead to a spontaneous change in the amount of liquid circulating and thus also the torque absorbed.

According to Figure 3 ^a , the trip edge ika. achieved by an approximately rectangular notch 18 in the outer region of the blade 13. According to FIG. 3b, this notch 18 has the contour of a quarter circle, while according to FIG. 3c it is approximately semicircular. The mode of action

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- 5 - Daini 9026/4

is about the same in all cases. Sheet metal shovels can be turned over in the area of the stumbling edges Ik or 18, so that they have very sharp edges there. According to Fig. 3d, the shell 15 extends beyond the trip edge Ik by about half and its edge 19 is tapered, the radial extension of the trip edge lk is located here at etvra lk% of the radial blade length. This embodiment results in a particularly good characteristic curve.

209088/0807

Claims (6)

- 6 - Daim 9026/4 Daimler-Benz Aktiengesellschaft Stuttgart Expectations ydrodynamic coupling, especially for power transmission Motor vehicles with a primary and a secondary shell, the inner walls of which merge into one another approximately semicircular in cross-section in the region of the flow circuit close to the axis and over a larger region of the shell depth in the outer region of the flow circuit remote from the axis run cylindrically, characterized in that on the secondary shell only in the outer region of the flow circuit the blades (13) are provided with a set back trip edge l4, l8) opposite the shell edge. 2. Coupling according to claim 1, characterized in that the stumbling edge Cl4, l8) extends radially to about five to fifteen Percent of the radial blade length - measured at the blade edges (17) - extends. 3 · Coupling according to claim 1 or 2, characterized in that that the setback of the stumbling edge with respect to the outer shell edge is approximately equal to its radial extent. Km coupling according to claim 3, characterized in that the stumbling edge (Ik) is formed by a bevel of the shovel (13) approximately below k °. 5. Coupling according to claim 3, characterized in that the trip edge (Iß) by a substantially rectangular Notching of the blade is formed. - 7 - Daisu 9026/4 6. Coupling according to claim k or 5 and with blades made of sheet metal, characterized in that the blades and optionally also the shell are provided with sharp edges in the area of the stumbling block. 7. Coupling according to claim 1, characterized in that the shell (15) projects over about half of the stumbling edge (ΐΛ) in the shape of a roof and is beveled at its edge (19) and that the stumbling edge (14) extends over about ik% of the radial blade length extends. 209886/0607 Blank page