DE4209211C2 - Load torque lock - Google Patents

Description

The invention relates to an LDS according to the preamble of Claim 1.

The LDS enables the Posi as a double-acting freewheel protection of a rotatable shaft (output shaft) in both directions of rotation and the drive of this rotatable wel le from the drive shaft in both directions.

The nor. Used in many areas of mechanical engineering paint, one-way freewheels allow the rotary movement of a shaft only in one direction of rotation, while in the other direction of rotation, the rotational movement of this shaft ge is blocked. The shaft is positioned here therefore only in a certain direction of rotation.

There are numerous use cases where adjustable Machines or devices positioning in both rotations directions is required.

This means that the Ma rail part, e.g. B. connected to a rotatable shaft ner tiltable container, in both directions dert can be driven while retroactively from Actuating torques acting on the shaft (Ab driving torques) in both directions of rotation have to.

Such locks can also be used as automatically switching double-acting freewheels are considered.

From the described requirements, the explains for such a design element used designation "Load torque lock", abbreviated: LDS.

In summary, it can be said that from the drive to the Ab drove an LDS and thus a rotation torque can be transmitted in both directions of rotation,  while, conversely, a rotary movement and therefore also a Torque in both directions of rotation from the actuator, al not transferred from the output to the drive of an LDS that can. In both directions of rotation now occurs through Sper LDS positioning the output shaft and thus of the actuator.  

In the known LDS constructions, the bearings of the drive shafts ( 6 ) and the output shafts ( 2 ) were provided as they correspond to the bearing design according to FIG. 1 which has been known for a long time and in practice up to the present. Although this bearing concept has been tried and tested for many applications, there are disadvantages that always have a greater negative impact, the higher the transmissible torques when locking (T _ab ) and driving through (T _an ).

The known bearing design of the drive shaft ( 6 ) with the bearing point A '(bearing 10 ) and the output shaft ( 2 ) with the bearing point B' (bearing 11 ) and with the intermeshing in bearing point C '(bearing 12 ) points in the Betriebszu states "drive through" and "lock"; Unlock the following disadvantages:

1) "drive through"

From Fig. 1 and 3 it can be seen that when driving through the eccentric, ie eccentrically at a distance (D ₁ -D ₂ ) / 2 acting from the shaft axis and with the drive speed number n _to circumferential force

e.g. B. assuming clockwise rotation of the drive shaft ( 6 ) at the stop B on the lever hub ( 1 ) and thus on the output shaft ( 2 ).

The drive shaft (6) and the output shaft (2) are thus defined by the force acting perpendicularly to the shaft axis with the drive speed n _of circumferential lateral force (radial force) F _u 'loaded.

Hereby occurs the transferable Antriebsdrehmo T ment _to dependent, because of the characteristic structure of the present LDS conception necessarily systemic occurring inner lateral load (radial Bela stung) of the input and output shafts and the bearings on. This is undesirable since the housing bearings ( 10 ) and ( 11 ) located in bearing points A 'and B' are continuously dynamic due to radial forces from the internal function of the LDS and without impinging on the external shaft journals of the attachments. and forces acting on the output shafts (e.g. radial and / or axial forces caused by tooth forces, belt tension, etc.). This undesirably reduces the bearing life from the outset in the known bearing design (LDS versions I to IV).

With large lateral forces

If, in addition, because of the radial and axial bearing clearances to a n _of circumferential tilting (buckling, skewing) of the input and output shafts (6 and 2) against each other.

This can be the secure locking and unlocking, i.e. the actual main function of the LDS as a safety component affect.

2) "lock"; "Unlock"

From Fig. 1, 2 and 3 it can be seen that when locking the eccentric, that is, eccentrically at a distance D ₁ / D 2 or ^m / 2 from the shaft axis
effective circumferential force

e.g. B. assuming clockwise rotation of the output shaft ( 2 ) at the stop A via the end piece ( 7 a) in the loaded first spring turns of the torsion spring ( 3 ).

Here, the torsion spring ( 3 ) after completing a small pivoting movement necessary for locking the construction parts that are in contact with the attachment point A (He belnabe ( 1 ), end piece ( 7 a), first loaded Federwindun gene) around the displacement (Blocking path) c frictionally locked against rotation in the ring ( 4 ). The frictional engagement of the torsion spring ( 3 ) seated under pretension in the cylindrical bore is enormously increased by pressing on the end piece ( 7 a), the pressure of the Federwin endings against the inner surface of the bore of the spring, which absorbs the peripheral force F _u , to the other, the free, unloaded spring end (here end piece 7 ) decreases.

One of the inner longitudinal dimensions d, e, f of the LDS as a function of the portion of the lateral force F _u acting on the lever hub ( 1 ) is applied via the output shaft ( 2 ) to the bearing point B 'with the housing bearing ( 11 ) and the other portion of the Lateral force F _u is transmitted via the inner bearing position C 'with the bearing ( 12 ) to the drive shaft ( 6 ) and from there to bearing point A' with the housing bracket ( 10 ).

As a result, an internal transverse load of the drive shaft and the output shaft and all bearings occurs that is dependent on the transmitted output torque (locking torque) T _and depends on the characteristic structure of the present LDS concept system.

This is undesirable, since the housing bearings ( 10 ) and ( 11 ) located in the bearing points A and B when locked statically by radial forces from the inner function of the LDS even without externally acting on the shaft cones of the drive and output shafts Forces (e.g. radial and / or axial forces caused by tooth forces, belt tension, etc.). As a result, the static load-bearing capacity is undesirably reduced from the outset in the known storage concept.

With large lateral forces

Furthermore, due to the radial and axial bearing play, the drive and output shafts ( 6 and 2 ) tilt against each other at standstill (buckling, misalignment).

This can be the secure locking and unlocking, i.e. the main functions of the LDS as a security structure affect part.

When intended "unlock" 1 and 3, after Fig. Z. B. assuming clockwise rotation of the slotted drive shaft ( 6 ), the end piece ( 7 a) on the stop position le B moves to the right until the frictional engagement of the housing ( 4 ; 5 ), which is initially still firmly in the cylindrical bore of the housing ( 4 ; 5 ) 3 ) is loosened by the desired "unlocking from behind" and the torsion spring is also dragged by the slotted drive shaft ( 6 ) when the remaining preload torque is overcome, ie it is turned.

An unwanted "unlocking from behind" must be avoided in any case, which is not guaranteed with the present known storage design according to FIG. 1 because of the above-described lateral force F _u , which is characteristic of the functional principle of the present LDS concept and which also acts proportionately on the bearing ( 12 ) of bearing C '.

Due to the already explained above, at large transverse forces F _u , standstill tilting (buckling, misalignment) of the input and output shafts against one another and to a lesser extent also due to the static load on the bearing ( 12 ) can be transmitted through this bearing increase friction torque and the drive shaft (6) take friction at a free and unrestrained rotatable drive shaft (6) (for. example, in pure drive-side manual drive and lack of drive-side drive train, which has a braking effect).

Here, because of the present LDS concept tion in itself to be regarded as particularly advantageous smooth unlocking process (very low ent locking torque) an unwanted "unlocking from behind" enter.

3) Stability of storage

The well-known for a long time and until today applied concept of storage of the input and output shafts (6 and 2) of FIG. 1 does not ensure the optimal storage stability as moments at the high input speed T _and the high output torques T _from (ho hey Locking torques) would be required.

The unsatisfactory storage stability is due to the flying bearing of the drive shaft ( 6 ) in the bearing point A 'with the two bearings ( 10 ) and the relatively small span (bearing distance e) from the drive shaft bearing in the bearing points B' with the bearing ( 11 ) and C 'with the bearing ( 12 ).

The disadvantageous consequences of a storage stability which is unsatisfactory, particularly when the LDS according to FIG. 1 is high in terms of torque transferability, have already been described above.

The invention has for its object to eliminate the disadvantages and thus to create an LDS, the safe "drive through", a safe "lock" and easy "unlock" to the highest transferable to drive and output torques without risk of Failure ensures and in which the housing bearing ( 10 ) of the bearing point A 'and ( 11 ) of the bearing point B' according to Fig. 2 when "driving through" completely unaffected by the effects of the system-related internal lateral forces F ' _u and F _{u and} remain at the entire storage (bearings A ', B', C ', D') of the LDS has optimum stability ( Fig. 2) with a simple and compact overall construction.

This object is achieved according to the invention in a ßen LDS solved by the features of claim 1.

In the exemplary embodiment in FIGS. 2 and 3, this is achieved by providing only one bearing point as housing bearing for the slotted drive shaft ( 6 ) and for the output shaft ( 2 ).

These are the bearing point A 'with the bearing ( 10 ) and the La gerstelle B' with the bearing ( 11 ) each in the housing ( 4 with 5 and 8 ). These two housing bearings have a large bearing spacing f from one another (span of the bearings).

A floating bearing of the drive shaft ( 6 ) is not necessary.

The drive and output shafts are also stored twice in each other in the bearing point C 'with the bearing ( 12 ) and in the bearing point D' with the roller bearing ( 13 ) not shown in Fig. 2 (for design reasons a needle bearing).

Sliding bearing according to a demanding 3 was shown in Fig. 2.

The bearings C 'and D' for the two interlocking bearings gen have the large bearing distance (g-d) from each other.  

This optimized storage proposed according to the invention concept leads to a simple and reliable con structure and ensures optimal stability of all moving parts of the LDS, especially the two waves.

As a result, an increased torque transferability (T _on and T _off ) with comparable main dimensions and, with the additional consideration of the improvement of the bearing concept according to the invention, enables a very simple and extremely compact design. For LDS as an important safety component in a powertrain, this progressive design brings the desired advantages with regard to:
Space requirements, operational safety, costs, weight, heat when driving through, universal installation and attachment options for the LDS as a compact unit, etc.

For the operating state "drive through" has been achieved by the inventions inventively according to claim 1 storage concept ( Fig. 2) that the bearings of the two Ge housing bearings A 'with the bearing ( 10 ) and B' with the bearing ( 11 ) completely remain unloaded, since the system-related in other lateral forces F _u 'and F _u in the two interlocking positions of the input and output shafts in the bearings ( 12 ) of bearing C' and ( 13 ) of bearing D ', their bearings always only statically (or valid for the bearing ( 13 ) according to claim 2 not at all) are lifted. The housing bearings ( 10 ) and ( 11 ), which are completely unloaded when driving through, are thus fully available for absorbing external axial and radial loads on the two external shaft journals of the drive and output shafts.

To design the invention will propose according to claim 2 that the bearing distance d of bearing A 'with the bearing ( 10 ) for the storage of the drive shaft ( 6 ) in the hous se ( 4 with 5 and 8 ) to the bearing C' with Bearing ( 12 ), which is one of the two inter-bearing arrangements of the drive shaft ( 2 ) in the drive shaft ( 6 ), is chosen to be as small as possible, preferably should go towards 0
(d → 0).

This ensures that especially when "locking" the Storage stability of the LDS taking into account the occurring great lateral force

is optimized in that the proportion F _{C 'of} the shear force F _u , which is transmitted via the bearing position le C' to the bearing ( 12 ) via the closed hollow shaft area of the drive shaft ( 6 ) to the bearing point A 'with the bearing ( 10 ) is then practically transmitted on a common line of action if the distance d goes to 0 (d → 0). There can then be no tilting moment (transverse moment) M = F _{C ′} · d on the drive shaft ( 6 ), which means that the drive and output shafts are tilted to a standstill (buckling, misalignment) against each other and in the bearing point D ′ with the bearing ( 13 ) would cause a bearing force F _{D '} <0.

As with "locking", he is also "driving through" handed stable storage with the largest possible storage stands f and (g-d) with (d → 0) at the occurring highs internal lateral forces

important prerequisite for perfect function.

To further develop the invention is proposed according to claim 3 ( Fig. 2), the intermounting of the drive shaft ( 6 ) on (according to Fig. 2: right) term end of their slotted hollow shaft area on the output shaft ( 2 ) in the bearing D 'instead of a rolling bearing ( 13 ) advantageously to make a (narrow) plain bearing tion.

This creates axial space so that the LDS can be constructed more narrowly. Furthermore, the costs for the roller bearing ( 13 ), which would be a Na dellager for design reasons, are saved.

The plain bearing is instead of the roller bearing at the bearing point D 'possible because of the proposal according to the invention in claim 2 to let the bearing distance d go to 0 (d → 0), whereby the plain bearing D' remains practically unloaded when "locking" (F _{D ′} → 0).

There is thus when locking the (small) Schwenkbe movements of the lever hub ( 1 ) and thus the output shaft ( 2 ) around the locking path c not the risk of unwanted "Ent lock from behind" by frictionally driving the drive shaft ( 6 ) because of In the case of plain bearings, higher friction torque is to be expected compared to the rolling bearing. A frictional entrainment via the bearing ( 12 ) of the bearing point C 'does not occur because a roller bearing (preferably a needle bearing; cage-guided needles or vollna delig) is provided and there is no tilting (buckling, crooked) of the drive and output shafts can occur, as has already been stated.

In claim 4 protection is also sought for the variant at the bearing point C ', instead of the roller bearing ( 12 ) described above, a slide bearing despite the expected high radial force F _C' when "locking". The prerequisite for this is that a type of plain bearing is selected which, in the case of the small pivoting movements when locking, has only very small friction torques in order to reliably rule out an unwanted “unlocking from behind”.

• - In summary, it is found that the LDS proposed according to the invention has the following advantages over the known designs:
  • - All bearings of the input and output shafts ( 6 and 2 ) are stable, statically determined and have the largest possible bearing distances f and (gd) with d → 0.
  • - The inner bearings of the input and output shafts ( 6 and 2 ) are due to the two interlocking bearings in C 'and D' with the largest possible bearing distance (gd), as well as in the bearing points A 'and B' with the greatest possible bearing distance f, designed and arranged that the two housing bearings A 'with the La ger ( 10 ) and B' with the bearing ( 11 ) when "driving through" by the system-related internal transverse forces (internal radial forces) are not acted upon, but these two Housing bearings run completely unloaded and are therefore available for absorbing any external additional loads on the external shaft journals of the drive and output shafts (e.g. external radial and / or axial forces).
  • - A bearing load by an internal radial force F _{D '} (internal transverse force) at the bearing point D' is not present when driving through.
    Tilting (buckling, misalignment) of the input and output shafts ( 6 and 2 ) against each other cannot occur.
  • - At the bearing point D 'a simple (narrow) plain bearing can be provided in a space-saving and cost-effective manner instead of a more complex roller bearing.
  • - There is no danger of unwanted "unlocking from behind" when "locking", ie the operational safety of the LDS as a safety component is guaranteed.
  • - The LDS according to FIGS. 2 and 3 represents a balanced con construction, which is very simple and extremely compact and which, as a self-contained unit, is independent in a drive train or as a built-on or built-in unit or combined with various types of couplings high torque transfer availability when "locking" and "driving through" and with high operational reliability is versatile.

Description of the exemplary embodiments of the invention shown in FIGS . 1, 2 and 3 according to claims 1 to 4:

• - Fig. 1: Front and side view of a known LDS with the hitherto usual and also today used situation conception.

With reference to FIG. 1 the known LDS will now be explained, the device for use in drive and Positionierein a tiltable container (z. B. a Gießpfan ne) is determined.

This explanation is also valid for the basic structure and the basic functions of the improved LDS proposed according to the invention and shown in FIGS. 2 and 3 as an exemplary embodiment.

The lever hub ( 1 ) is connected to the output shaft ( 2 ) which represents the actuator to be positioned in both directions of rotation (e.g. the tiltable container coupled to the output shaft).

The cylindrical torsion spring ( 3 ) (with circular or at its, e.g. rectangular wire cross-sections) with the two spring ends bent inwards sits under tension, which should be as small as possible due to the easier driving through, in the hardened and ground cylinder bore of the ring ( 4 ). This ring is firmly connected to the housing ( 5 ).

When locking of the output shaft (2) of the LDS we kenden output torque T _from the torsion spring (3) is obtained by the pressing of the lever hub (1) at the stop point A - if the output torque T _from veering is - the applied inwardly bent spring end additional Lich spread apart and locked against twisting in the ring ( 4 ) because the frictional engagement of the prestressed in the cylindrical bore torsion spring is enormously reinforced by pressing, the pressure of the spring turns against the inner surface of the bore from the spring end, which the circumferential force takes up to the other, the free spring end, decreases.

The drive shaft (6) is formed in the region of the two according to NEN bent spring ends as a slotted sleeve (hollow shaft) in such a manner that the torsion spring (3) over the respective stop point - stop point B, if the on drive torque T is _in clockwise - the infra gekom can be relaxed, inwardly bent spring end.

The frictional engagement is loosened, and the torsion spring ( 3 ) can be dragged along by overcoming the remaining pretensioning torque from the drive shaft ( 6 ), ie rotated.

The drive torque T _an is in this operating state of driving through the adjacent, inwardly bent spring end from the drive shaft ( 6 ) to from the drive shaft ( 1 , 2 ) directly positively transmitted via the impact point B.

An LDS of the type described can only be reliable then work when for the games (tangential games, twisting games) following Bedin reproduced here in simplified form are fulfilled:

a <b <c.

Only then can the full output torque T _ab be braked in both directions of rotation in all possible operating states without hindrance by the stop faces of the slotted sleeve of the drive shaft ( 6 ), that is to say blocked.

The same applies when driving through that only if the conditions mentioned are met, the torsion spring ( 3 ) is unlocked without a wall, and the drive torque T _on in both directions of rotation without obstruction by the striking surfaces of the slotted sleeve of the drive shaft ( 6 ) the drive shaft to the output shaft ( 1 , 2 ) can be transferred.

The games are shown in Fig. 1, side view, and arise when the drive shaft ( 1 , 2 ) and the drive shaft ( 6 ) come into contact with the stop points A and B against the inwardly bent spring ends of the pretension in with slight clockwise rotation the cylindricity rule bore of the ring occurs (4) seated a torsion spring (3) before a torque transmission from T _and / or T is present _from.

The play a must be greater than the displacement path (block way) c the loaded spring end at the stop A when locking to build up the additional friction between  spring turns and bore, so that when Lock a simultaneous unlocking of the torsion spring (un deliberate "unlocking from behind") cannot occur.

• - Fig. 2 and 3: front and side view of the proposed to the claims 1 to 4 proposed optimized storage concept.

Referring to Figs. 2 and 3, the detailed Be is now scription of FIG. 1 supplemented.

The above description remains fully valid except for the note that instead of the inwardly bent spring ends of the torsion spring ( 3 ) spring end pieces ( 7 and 7 a) can be used in an advantageous manner, the functional when locking, unlocking and driving through in essence correspond to the bent parts of the two spring ends of the torsion spring.

The end pieces can, to some application examples mention as slotted or split clamps be guided, which are frictional, positive or are integrally connected to the spring wire.

The end pieces can also through the spring wire itself (e.g. also by upsetting, by radial pins in the spring wire etc.).

In FIGS. 2 and 3, the spring support rings (9) can be axially tensioned with "ge Gewindegän" over the first, that is, slightly exploded torsion spring (3). The resulting Axi alsspiel S _a ensures that the spring turns can no longer touch each other.

All improvements made it possible to considerably increase the torque transferability for "driving through" (T _on ) and "locking" (T _off ). The storage concept of the LDS, which is to be improved according to the invention, must take this increase to 2 to 3 times the value into account.

In the bearing points A 'with the bearing ( 10 ) and B' with the bearing ( 11 ), which have the greatest possible bearing distance f, the drive shaft ( 6 ) and the output shaft ( 2 ) are mounted in the housing ( 4 with 5 and 8 ) .

The additional support of the drive and Abtriebswel le takes place through the two inter-bearing in the bearing C 'with the bearing ( 12 ) and in the bearing point D' with the narrow slide bearing shown in Fig. 2 of the slotted drive shaft ( 6 ) on right end of their slotted hollow shaft area (sleeve area) with the largest possible bearing distance (gd), where d should go towards 0 (d → 0).

The axial support of the two shafts in one direction tion, here inwards, takes place via contact point E. This simple support is only possible because of the very small swiveling movements of the drive and output shaft len against each other.

• - Result: The LDS according to FIGS. 2 and 3 is very simple and extremely compact as a self-contained machine part or as an installation of the add-on unit. B. be attached and combined via a drawn flange fastening univer sell. There are also combinations with different types of coupling, such as. B. Si safety slip clutches possible.

The lubrication can e.g. B. as oil lubrication or grease Lubrication over its own filling or in combination with the lubrication circuit of the connected machine (e.g. gearbox).

Claims (4)

1. load torque lock with a pretensioned egg in a bore torsion spring, the locking of the initiation of a circumferential force depending on the direction of rotation from the drive-side torque in one of the two bent spring ends or in one of the end pieces of the two spring ends, and when driving through Depending on the direction of rotation of a drive-side torque, a circumferential force is transmitted from the drive to the output to the lever hub ( 1 ) connected to the output shaft ( 2 ), characterized in that the drive shaft ( 6 ) and the output shaft ( 2 ) each have a bearing point (A ′ or B ') in the housing ( 4 with 5 and 8 ) with a large bearing spacing f of the bearing points (A' and B ') from one another, the drive shaft ( 6 ) having the one bearing point (A') with the one bearing ( 10 ) and the output shaft ( 2 ) the other bearing (B ') with the other bearing ( 11 ) are assigned, and in addition the drive shaft ( 6 ) and Output shaft ( 2 ) twice in each other in other bearings (C 'and D') with other bearings ( 12 and 13 ) with a large bearing distance gd. 2. load torque lock (LDS) according to claim 1, characterized in that the axial distance d, the one bearing (A ') with the bearing ( 10 ) for the mounting of the drive shaft ( 6 ) in the Ge housing ( 4 with 5 and 8 ) to the further bearing point (C ') has with the bearing ( 12 ), which is in the form of a bearing of the drive shaft ( 2 ) in the drive shaft ( 6 ), is as small as possible and preferably goes towards 0 (d → 0) . 3. load torque lock (LDS) according to claims 1 and 2, characterized in that the intermeshing of the slotted drive shaft ( 6 ) on the output shaft ( 2 ) in the further bearing point (D ') instead of a roller bearing ( 13 ) via a plain bearing. 4. load torque lock (LDS) according to claims 1 to 3, characterized in that the intermeshing of the output shaft ( 2 ) in the drive shaft ( 6 ) in the other bearing (C ') instead of a roller bearing ( 12 ) via a plain bearing he follows.