DE2512987A1 - OVERLOAD CLUTCH - Google Patents

Description

2 κ ι? η - '/

PAl KNTANWAJL.TE * "" "

j. II. NEGEX THANKS ι-ΐ073> · dipl.-ing. II. HAUCH · dipl.-phys. W. SCHMITZ DiMWNG. E. GRAALFS · dipiwng. W. AVEIINERT dipl.-phvs. W. CARSTENS

HAMBURG-MUNICH

Pi'fTsF ^ iYiM ^ y'tO ^ ¹¹¹¹¹ * ¹ ' ¹¹ ' ^8OO ° ^{mCnCIIEN 2} * MOZARTSTR. 23

TELEPHONE (089) 5 38 O5 80

TELEGn. NEGEDAFATEN'T MUXCHESi

F. Jos. Lamb Company

5663 East Nine Mile Road 2000 AD 36 ■ new wall u

xj «· t- / _IT o. TELEPHONE (040) 30 7128 and 30 4115

Warren «Mxch./USA

¹ TELEQH. .VEQEDAiATENT HAMBUHQ

John Henry Brems MUNICH, 2 ^L " >'-"-' 1375

32867 White Oaks Trail
Birmingham. Me, / USA

Overload clutch

The invention relates to an overload clutch with a single angular position between the mutually movable coupling parts, in which there is a drive connection between the rotating drive part and the coaxial rotating output part, _etc.

The invention is intended to create an overload safety clutch which can be used up to a predetermined load of the output part transmits a torque from the drive part to the output part and when this is exceeded Limit value, the transmitted torque drops to a value close to zero.

The invention is also intended to create an overload clutch which is advantageous for inexpensive manufacture

ORIQtNAL! MSPECTED - 2 -

5 0 9 3 ^ 3/0332

25Ί2987

Has structure in which the release torque is determined by the design a single component can be precisely adjusted and the release torque afterwards by modification or Exchange of this single component can be modified.

The invention is also intended to create an overload clutch in which, after the clutch has been disengaged, only a very small one Towing force is observed and only a minimum of sliding contact occurs between the rotating coupling parts.

The invention is also intended to create an overload clutch be that only in a single angular position between the Drive part and the output part engages again.

Furthermore, the invention is intended to create an overload clutch that have the ability to transmit high torques with little space requirements and with the simplest possible mechanical Structure connects.

In the following, the invention is explained in more detail using exemplary embodiments and with reference to the accompanying drawings, In this show:

1 shows a section through part of a first according to the invention Overload clutch, some parts are shown in plan;

FIG. 2 shows a section through the overload clutch according to FIG. 1 along line 2-2;

509848/033 2 - 3 -

Fig. 3 and 4 force diagrams in which the forces according to amount and direction are shown, which is designed when the specified torque for which the clutch is exceeded is to occur}

5 shows a section through a second overload clutch according to the invention, some parts are shown in an ali view}

6 shows a section through the overload clutch according to FIG. 5 along the line 6-6}

6a shows a section through part of an overload clutch which is derived from the overload clutch shown in FIG. 5 by modification further overload clutch according to the invention}

7 shows a section through part of a third according to the invention Overload clutch, some parts are shown in plan} and

8 shows a section through the overload clutch shown in FIG along line 8-8.

In the overload clutch shown in FIGS. 1 and 2, a drive shaft 10 is supported in a bearing 12. The latter is mounted in a housing 14. Further bearing for the drive shaft 10 and drive means are not necessary for understanding the invention and _o are therefore not illustrated A cage 16 in the form of a provided at one end with a flange sleeve on connected by bolts or otherwise rotationally fixed to the end of the drive shaft 10 the Cage 10 is a gear

509848/0332 _ / _f _

arranged rotatably, care being taken for the lowest possible sliding friction between these parts. The gear 18 is fixed in the axial direction by a retaining ring 20, which in turn by one or more locking screws 22 on free end of the cage 16 is attached. A suitably guided, rectilinearly movable toothed rack 24 engages with the toothed wheel 18 and in the arrangement shown represents the part to be driven by the overload clutch.

In the cage 16, a longitudinal slot 26 is formed into which a roller 28 is fitted but rotatably with little play. The roller 28 for its part is seated in a longitudinal groove 30 which is formed in the jacket of the axle bore of the gear wheel 18. The longitudinal groove 30 is provided with converging side walls 32. The cage 16 has two further slots 34 and 36 which are arranged at a close distance from one another and at the same distance from the opposite end of a diameter penetrating the longitudinal slot 20 on both sides thereof. Lugs 38 and 4o are rotatably arranged in the slots j} h and _o 36 and are in contact with a non-grooved cylindrical bore section 42 of the gear wheel 18.

The three rollers 28, 38 and 4o are biased outward in the radial direction by a spring ring 44 _o This spring ring, which can be made of material used for the production of springs, for example, has a substantially uniform cross-section and is precisely in the non-biased rest position circular shape. The outer diameter of the spring washer

509848/0332

44 is slightly larger than the diameter of the through that in radial direction on the inner surface of the lumps 28, 38 and 4o predetermined circle. For installation in the coupling, the spring ring 44 must therefore be deformed by means of expanding pliers or another suitable tool.

Such spring washers are known to those skilled in the art because of the accuracy and linearity of their force-deformation curves, with a tensile or compressive load acting on a single diameter being possible. With such a load, the deformation of the spring washer in the direction of the corresponding diameter is given by the following equation:

D = K ^
£ 1

It is

D = deformation

K = constant

P = attacking force

R = radius of the neutral fiber of the ring E = modulus of elasticity

I = area moment of inertia of the ring

If the applied force is measured in kilograms and the unit of length is 1 cm, the constant K = 0.027 (when measuring the force in lbs, and using the unit of length inches if K is correspondingly = 0.14 ° -).

The torque limit of a given clutch depends on

509848/0 33 2

- 6 - 25Ί2987

the deformation of the spring ring kk which generates the preload and the contact angle of the roller 28 located in the longitudinal groove 30, as has been explained above. If the torque transmitted between the cage 16 and the gear 18 exceeds this limit value, the roller 28 rolls out of the longitudinal groove 30, whereby the spring ring kk is further deformed between the roller 28 and the rollers 38 and 40 serving as a support _o the roller rolls 28 on the cylindrical bore section k-2 of the gear 18, there is a real rolling between all the heavily loaded parts of the coupling _o The only sliding contact in the coupling is between the rollers and the walls of the slots provided in the cage, and this sliding contact is only associated with very small forces because of the low friction of the arrangement. When the cage 16 rotates with respect to the gearwheel 18, the spring ring kk rotates at an inkelgeschwindigkext which is slightly greater than twice the angular velocity _{a observed between these parts}

If the cage 16 has been rotated slightly less than 180 ° counterclockwise with respect to the gear 18, the roller 38 meets the longitudinal groove 30 provided in the gear 18 is provided by dei 'its adjacent roll 40, while normally dis supporting force under the rollers 38 and wxrd 4o divided _o After the roll 38 in sections on the other side of the longitudinal groove 30 is again in contact with the cylindrical surface of the non grooved fjohrungs it has entered hz , the role is knocked out

509848/0332 " ^? "

the longitudinal groove 30. For the time in which the roller 40 enters the longitudinal groove 30, the entire supporting force is taken over by the adjacent roller 38. Since the supporting force is thus transmitted from two rollers to one, the spring ring is only slightly deformed when the rollers 38 and 40 are moved over the longitudinal groove. As a result, the rollers 38 and ho also only enter the longitudinal groove 30 very little. This results in only a very slight out-of-roundness in the freewheeling of the disengaged clutch. The torque to be assigned to this out-of-roundness is much smaller than the torque that can be transmitted in the engaged state of the overload clutch.

After a rotation of the cage 16 relative to the gear 18 of 36O ⁰ again the role 28 passes fully into the longitudinal groove 30th The full limit torque is then required again to disengage the overload clutch. The re-engagement of the overload clutch can be brought about by turning in any direction of rotation. In common applications, sensors that are arranged on the outside are usually provided, which detect a relative movement between the drive shaft 10 and the gearwheel 18. The sensors then cause the drive device assigned to the drive shaft 10 to stop, the direction of rotation of which is then reversed in order to re-engage the clutch.

After a series of disengagement processes and re-engagement processes, the spring ring hh can drift from one side to the other in an unforeseeable manner until it touches the cage and further drifting is limited. To that with

509848/0332

To overcome frictional sliding resulting from such contact, two auxiliary rollers 46 and 48 can be used. The cage 16 has two further slots 50 and 52 which are arranged at opposite ends of a diameter which is arranged essentially perpendicular to the diameter running through the longitudinal slot 26. The rollers 46 and 48 are arranged with play in these additional slots, the diameter of the rollers 46 and 48 being slightly larger than the thickness of the wall of the cage 16. If the spring ring wants to drift from one side to the other, it therefore contacts the roller 46 or the roller 48. This prevents any further drifting movement with the production of rolling contact with one of the rollers 46 and 48.

As has already been stated above, the trigger depends on the edrela moment the coupling partly from the deformation of the spring ring 44, which is responsible for the preload. In Figo 3, F represents the

KU

Roller 28 as a result of the deformation of the spring ring 44, which is responsible for the preload, force darj θ is the angle between the side wall 32 of the longitudinal groove 30 and a line extending in the radial direction from the center line of the cage 16 and the gearwheel 18; F is the tangential force which is required to roll the roller 28 out of the longitudinal groove 30 over the side wall of the same. The following applies: tan θ = ¹ Ro

^F T

or

F = ^ Ro
tanQ

509-848 / 0 332

If R is the radius to the point of contact, then this is the generated torque T

T = RF = R ^F Ro
tan ©

F is, however, not a static _o If the roller 28 moved in a direction out of the longitudinal groove 30, the deformation of the spring ring is increased kh; thus the force F also increases.

Fig. H is a schematic representation in which the curvature of the side wall of the longitudinal groove 30 is shown, which is necessary to obtain a force F_ of constant magnitude during the movement of the contact point of the roller. In FIG. K , P represents the initial contact point of the roller with the side wall of the longitudinal groove. If the roller has been moved to another point Q, the following conditions exist: The spring ring kh has been deformed by an additional distance y while the roller has moved a distance χ in the tangential direction} is the spring constant of the spring ring kk k, then the radial force F _{T obtained at point Q is}

F = F + kv
R Ro -

At point Q applies

, _. dx

tan G = -τ-

dy

As a result, one obtains

F = ^F R = F
T - ~ R dx
dx

dy

dx = F _R dy

dx = (F _Dn + ky) dy

509848/0332

Ro

- 10 -

- 10 By integration one obtains

or

F 2

χ = ^L Ro - ^ -

F 2F T T

This equation specifies the curve according to which the longitudinal groove 30 must open above the normal point of contact with the roller, so that the tangential force remains constant during the disengagement. The constants of this equation represent design parameters darο As the form of the equation above shows, the Shape of the groove that of a parabola "

Figures 5 and 6 show another embodiment of a erfxndungsgemäßen overload coupling, wherein the spring ring is arranged outside of the rollers _o A shaft $ k is keyed by a spring 58 with a cage 56th An extended sleeve-shaped portion of the cage 56 can run freely on a second shaft 60 if the effect of rollers to be described is neglected. A primary slot 62 is cut into the cage 56, in which a roller 6k, however, is movably arranged with little play. The roller 6k extends through the slot 62 and sits on inclined side walls of a groove 66 formed in the shaft 60,

Two secondary slots 68 and 70 are closely spaced from one another provided in the cage 56 and are equidistant to arranged on both sides of the opposite end of a diameter running through the primary slot 62. Two secondary roles

509848/0332 - 11 -

71 and 72, however, can be moved in the with little play Secondary slots 68 and 70 are arranged and lie on the cylindrical Outer surface of the shaft 60. The three rollers 64, 71 and 72 are all three in the radial direction by a spring ring 74 inwardly biased, which in turn essentially is subjected to tensile stress along a single diameter. By one or more locking screws 78 is a Retaining ring 76 attached to the free end of the cage 56 to the To hold the spring washer in the axial direction in the position encompassing the rollers.

The overload clutch shown in Figures 5 and 6 works just like the overload clutch shown in Figures 1 and 2} only the spring washer is subjected to tension in it, while the spring ring 44 of the overload clutch shown in Figures 1 and 2 is subjected to pressure.

Figures 6A, 7 and 8 show modifications of an outer spring ring having an overload coupling according to the Figures 5 and 6 _O In the embodiment of FIG. 6a, the secondary rolls 7I and 72 secondary slit 79 standing formed in tangential contact inside a single in the cage 56 arranged. The extent of the secondary slot 79 in the circumferential direction is just sufficient to accommodate the rollers. In this arrangement, the rollers 71 and 72 enter the groove 66 to a lesser extent than when they are arranged at a distance from one another, as is the case in the embodiment according to FIG. This reduces the inequality in the freewheeling torque that occurs when

509848/0332. _ΛΡ _ _

Arriving of the secondary rollers at the groove 66 is observed.

In the embodiment of the invention shown in FIGS. 7 and 8, a primary roller 80 is shorter than a single secondary roller 82 _O. The groove 8k formed in the shaft is also shorter than the secondary roller 82. If the overload clutch is disengaged, the secondary roller 82 runs over the groove Sk ₉ so it cannot fall into the hat 8k , since the outer ends of the secondary roller 82 at each of the two ends of the groove 84 are flushed against the syliiicl ^ i see surface of the shaft ₅

For every practical A ^ ofü & ^ ngsiforäi soIIusk clis Balkenfoelastiaiigeii tincl Sontektfcalastungeii des? Ed3rraiiges osrocliHst ws-r-deii ", to ensure that the ZtippZ. ^ Ng iiiiiwrlialb des Bsss is free of errors! Maisriales des Federring®s is siclier-placed «In the case of vcrgsgefcs ^ er in the direction of a through = Hi = SSSrE occurring Yer-ros-inuäg of the Feder-riiiges there is a maximum sulcus wallstax ^ ke- for the Fsdsrringo This then means a limit value for the srreiohfcar-s z'-adial force »Is bsi the same geometric axis length. larger Auslösedrehmomeiit required, this can be achieved visrdsnj that shown on the outside of an externally lisgsnden FedEx ^ rijiges _s as shown in Fig. 8}, a second spring ring is placed 86 »With internal spring ring is an additional spring ring according lying on the inside of the inside To arrange spring washer. In both cases, the additionally provided spring ring must be arranged so as to slide on the contact surface with the first spring ring.

- 13 509846/0332

Claims (1)

Patent claims: Overload clutch with a single angular position between the mutually movable coupling parts, in which there is a drive connection between the revolving drive part and the coaxial revolving driven part, characterized in that one of the coupling parts has a circular cylindrical bearing surface (42, öO) which is only supported by a single in Longitudinal groove (30 »66, 84) arranged in it is interrupted, and that the other coupling part has a single primary slot (26 _f 62) running in its longitudinal direction and a secondary slot arrangement (34, 36, 68, 70, 79) running in its longitudinal direction ) has »the latter being arranged essentially diametrically opposite the primary slot (26, 62)} that a primary roller (28, 64, 80) serving to establish a drive connection is arranged in the primary slot (26, 62) and when the clutch is engaged in the groove (30 » ^ * 84) is seated; that in the secondary slot arrangement (34, 36, 68, 70, 79) a secondary roller arrangement (38, 40, 71 »72, 82) is arranged; and that a resilient ring (44, 74, 86) running in the circumferential direction with a substantially constant cross-section and in the unloaded state substantially circular shape the primary roller (28, 64, 80) in the longitudinally extending groove (30, 66 , 84) biased and supported by the secondary roller assembly (38, 40, 71, 72, 82) which deforms the ring (44, 74, 86) into an oval so that its diameter is reduced in one direction and in one 509848/0332 the direction perpendicular to this is enlarged, the secondary roller arrangement (38, 40, 71, 72, 82) being seated in the groove (30, 66, 84) when preloaded by the ring (44, 74, 86) during rotation between the driven part and the drive part is prevented _o Overload clutch according to claim 1, characterized in that the secondary roller arrangement has a plurality of rollers (38, 4o5 71, 72) arranged at a short distance, the distance between these rollers being selected so that when one of the rollers (38, 4o} 71 , 72) on the groove (30, 66, 84) an adjacent roller deforms the resilient ring (44, 74, 86) sufficiently to allow the first roller to easily roll out of the groove (30, 66, 84) _O 3. Overload clutch according to claim 1 or 2, characterized in that the secondary protection arrangement has a plurality of closely spaced slots (34, 36 \ 68, 70), in each of which one of the secondary rollers (38, 40} 71, 72) Takes place, 4. Overload clutch according to claim 1, characterized in that the secondary roller arrangement has a roller (82) which has a greater length than the length of the groove (84), and that the secondary roller (82) by means (46, 76) in such a way is positioned so that their opposite ends over the opposite ends of the longitudinally '- 15 - 509848/0332 running groove (84) so that the secondary roller (82) do not sit in the longitudinal groove (84) can. 5. Overload clutch according to one of Claims 1 to 4, characterized in that the longitudinally extending groove (30 » 66 _f 84) has curved side walls which, in the area between the primary roller (28, 64, 80) and which accomplish the power transmission Point and the cylindrical surface (42, 6o) of one of the coupling parts lying section has a parabolic shape « 6. Overload clutch according to one of claims 1 to 5 »thereby en characterized in that the roles are first / substantially loaded ring along a single diameter (74) and one coaxial with the first ring (74) on this sliding second ring (86) are biased. 7. Overload clutch according to one of claims 1 to 6, characterized characterized in that the one coupling part has a central bore (42) that the ring (44) in the bore (42) is arranged offset in the radial direction inwardly to this, and that the other coupling part (16) in radial direction between the aste coupling part and the ring (44) is arranged. 8. Overload clutch according to one of claims 1 to 6, wherein one of the coupling parts has a shaft, characterized - 16 - 5 09848/0332 characterized in that the longitudinal groove (66) is formed on the cylindrical outer surface of the shaft (6o), that the resilient ring (74) surrounds the shaft (6o) at a distance, and that the other coupling part (56) i radial direction is arranged between the shaft (6o) and the ring. 9 · Overload clutch according to one of Claims 1 to 8, characterized characterized in that the second coupling part comprises a hollow sleeve having a pair of diametrically opposed Slots (50, 52) is formed on a substantially = borrowed perpendicular to the primary slot (26) penetrating diameter are arranged that each of the two additionally provided opposite slots (50, 52) receives a roller (46, 48), and that these rollers (46, 48) have a diameter which is at least a little larger than the radial thickness of the Sleeve to avoid sliding contact between the resilient ring (44) and the other coupling part (ΐβ). 10. Overload clutch according to one of claims 1 to 9 »characterized in that the other coupling part is a sleeve and that the primary slot and the secondary slot arrangement run in the radial direction through the wall of this sleeve o 11. Overload clutch according to one of claims 1 to 10, characterized characterized in that the secondary law arrangement has a 509848/0332 - ¹ 7 - has a single secondary slot (79). 12o overload clutch after. Claim 11, characterized in that that the secondary rollers (71 »72) are arranged in contact substantially in the tangential direction, and that the Secondary slot (79) has an extension in the circumferential direction, which essentially corresponds to the sum of the diameters of the secondary rollers (71, 72) 13 overload clutch according to claim 12, characterized in that that the secondary rollers have two rollers (71 »72), all of which have substantially the same diameter. 509848/0332 Blank