EP2235311B1 - Transmission unit and drive transmission unit - Google Patents

Description

State of the art

The invention relates to a transmission unit with a, a wrap spring load torque lock for locking a torque introduced by a driven-side coupling element according to the preamble of claim 1 and a drive transmission unit according to claim 9.

From the DE 10 2005 012 938 A1 is a drive gear unit with a wrap spring load torque lock known. In this case, the wrap spring is arranged on or in a rotationally fixed shaft and cooperates with a single driver of the coupling element such that the driver, when a torque is introduced into the wrap spring of the coupling element, the wrap spring clamped against the outer or inner circumference of the shaft and so the output side torque locks.
The known drive gear unit has proven itself particularly in manual positioning systems and in actuators in the automotive sector. However, there are efforts to further minimize the wear of the known transmission unit.

With the DE 9203486 U1 a power window drive of a motor vehicle has become known, in which a load torque lock is realized by means of a wrap spring. In this case, two radial ends of the wrap spring engage in corresponding recesses of a driver or between a driver and a coupling part.

The DE 2651607 A1 also discloses a window lift drive in which a torque is transmitted to a gear by means of a crank pin. In this case, a wrap spring between the crank pin and the gear is arranged as a load torque lock, wherein radial ends of the wrap spring engage in recesses between gear projections and crank pin projections.

In the EP 0012250 A1 is also a window with a load torque lock known, in which a wrap spring between a drive pin of a transmission element and a housing-fixed sleeve is arranged

Disclosure of the invention Technical task

The object of the invention is to propose a transmission unit optimized with regard to wear behavior. Furthermore, the object is to propose a correspondingly optimized drive transmission unit.

Technical solution

This object is achieved with regard to the gear unit with the features of claim 1 and with regard to the drive gear unit with the feature of claim 9. Advantageous development of the inventions are specified in the subclaims.

The invention is based on the idea, in a, a load torque lock with wrap spring having gear unit on the coupling element not only provide a driver for receiving the drive torque, but at least two drivers. In an embodiment of the coupling element with at least two drivers, the drive torque introduced by the transmission element is not only applied, as in the prior art, by a single driver, but distributed over a plurality of carriers, whereby the stress on the individual carriers is minimized. As a result, wear phenomena that in known transmission units with load torque locks in the contact area between a stop surface of the transmission element and the only driver to watch, at least reduced. Disclosed is a transmission unit in which only the first driver cooperates with the wrap spring of the load torque lock and the wrap spring upon application of a driven-side torque on the cylinder element (outer cylinder member and / or inner cylinder member) braced. The at least one further driver then has no adjustment task or blocking function in the blocking case, that is to say when an output-side torque is introduced into the torque lock by the coupling element. The at least one other driver comes in the described. Embodiment only be used when a drive-side torque on the coupling element, that is transmitted to the driver from the transmission unit. The provision of several drivers has over the minimization of wear further advantages. Thus, the movement of the gear unit becomes more uniform by the provision of a plurality of drivers, which in turn minimizes the noise emission of the gear unit. In addition, the torsional backlash of the coupling element can be minimized relative to the transmission element. Preferably, the torsional backlash is less than 6 °. The cross section of the wrap spring may be round, rectangular or intermediate forms, such as take an oval shape.

Of particular advantage is an embodiment of the load torque lock, wherein at least one driver, preferably all drivers are formed in their contact area to a circumferentially adjacent component as a metal pin or as a metal sleeve. Here, the metal pin or the metal sleeve with advantage, in particular at right angles, on an arm pointing in the radial direction set the coupling element. Manufacturing technology, it is advantageous to set the metal pin or the metal sleeve already in the injection molding process by at least partially inserting the metal pin or the metal sleeve in an injection mold on the coupling element, in particular on the pointing arm in the radial direction. Preferably, the coupling element is designed as an injection molded part of a fiber-reinforced plastic. In order to provide the largest possible contact surface between the drivers and the adjacent components of the load torque lock, an embodiment is preferred in which these components, at least partially in at least one section form-congruent to the respective metal pin or to the respective metal sleeve, in particular concave, are formed.

In a further development of the invention is advantageously provided that the drivers of the coupling element are arranged distributed uniformly in the circumferential direction. In an embodiment with two drivers, the angle between the drivers in the sequence is 180 °, in one embodiment with three drivers 120 °. Due to the even distribution of the driver, the load on the coupling element is made uniform, which in turn has positive effects on the wear behavior and on the running properties of the gear unit.

It is particularly advantageous if the cooperating with the wrap spring diameter of the cylinder element, ie at an externally arranged wrap spring, the outer diameter of the cylinder element or the inner diameter of the cylinder element at a disposed within the cylinder element wrap is greater than 2 cm. This makes it possible, even large output-side torques safe to lock. In order to enable a low-friction operation of the gear unit, an embodiment is preferred in which the contact area between the wrap spring and the cylinder member has a coefficient of friction μ of about 0.14 For this purpose, the contact region is preferably greased.

In order to enable the first driver to clamp the spring on or in the cylinder element upon application of a driven-side torque, it is provided that the spirally formed wrap spring has ends which, depending on the arrangement of the wrap spring, protrude radially outward or radially inwards from the cylinder element ,

It is particularly advantageous that the first driver and / or an abutment surface of the gear unit does not rest directly on one end of the wrap, but in which the end of the wrap spring is at least partially received in a pressure piece is a receptacle for the end of the wrap preferably at least partially, preferably formed completely congruent with the Schlingfederende so that the introduction of force into the wrap spring can be done evenly and results in a lower bending moment of Schlingfederendes. As a result, the service life of the gear unit, in particular the load torque lock, can be substantially increased. In addition, it is possible by the provision of at least one pressure piece to reduce the angular tolerances of Schlingfederendenpositionen.

With regard to the concrete design of the plungers, there are different possibilities. Preferred is a Embodiment in which the at least one pressure piece is formed of plastic. It is conceivable to form the pressure piece of at least two thermoplastic shells, which are hot pressed together around a loop spring end. Alternatively, the formation of at least one pressure piece as a plastic injection molded part can be realized, wherein the plastic injection molded part is pushed either after its production on a loop spring end, or the wrap spring is molded directly in the injection molding machine with the pressure piece.

In a further development of the invention is advantageously provided that a guide is provided for the pressure pieces in the circumferential direction. In this case, the guide can be provided on the gear element and / or on the cylinder element and / or in a gear housing. Particularly preferred is an embodiment in which the at least one pressure piece is arranged in a, preferably curved contoured recess within the transmission element.

Of particular advantage is an embodiment of the transmission unit, wherein the transmission element has at least one first, preferably two spaced-apart first stops. The at least one stop acts upon the action of the drive torque either directly with one end of the wrap spring or directly with the end of the wrap spring receiving pressure piece, such that the wrap spring or the pressure piece is pressed against the first driver, so that in the sequence Wrap spring rotated together with the transmission element and the coupling element relative to the cylinder element.

Preferred is an embodiment in which the transmission element in addition to the at least one first stop has at least one second stop, in particular two second stops, which are associated with the second driver of the coupling element. The at least one second stop and at least one contact surface of the second driver are preferably arranged relative to one another in such a way that the at least one second stop is pressed against the contact surface of the second driver of the coupling element when the drive torque is applied and entrains the latter in the sequence. In this way, the drive torque is introduced not only on the first driver but also on the at least one second driver in the coupling element.

In a further development of the invention is advantageously provided that the first driver of the coupling element is designed and / or arranged such that it rotates upon the action of the output side torque of one of the ends of the wrap spring relative to the cylinder member such that the wrap spring is tensioned against the cylinder member and so the output side torque locks. It is particularly preferred if the first driver is not moved directly against one of the ends of the wrap spring, but against a previously described, with the wrap spring end pressure piece that is formed, preferably contoured, that a uniform force in the wrap spring and so that the lowest possible bending moment results.

The invention also leads to a drive gear unit with a previously described gear unit and an electric motor. The electric motor drives it directly or only indirectly, for example via a worm gear, the transmission element, which is designed as a gear on. Due to the provision of a designed according to the concept of the invention gear unit with a coupling element having at least two drivers, the service life of the entire drive gear unit is increased due to the resulting reduction in wear.

Of particular advantage is an embodiment of the drive gear unit, in which the coupling element is connected to transmit torque to a driven gear. It is also an embodiment conceivable in which the coupling element is integrally formed with the output gear. Particularly in the case of the last-mentioned variant, the output gear formed in one piece with the coupling element is preferably a plastic injection-molded part.

Brief description of the drawings

Fig. 1:

eine teilgeschnittene, perspektivische Ansicht einer Getriebeeinheit, die in einer Halterung aufgenommen ist,

Fig. 2:

die Getriebeeinheit gemäß Fig. 1 in einer teilgeschnittenen Ansicht ohne Halterung,

Fig. 3:

eine hälftige Längsschnittansicht der Getriebeeinheit gemäß Fig. 2 und

Fig. 4:

eine Draufsicht auf die in den vorgenannten Figuren gezeigte Getriebeeinheit, wobei aus der Figur das Zusammenwirken der einzelnen Bauelemente ersichtlich ist.

Further advantages, features and details of the invention will become apparent from the following description of preferred embodiments and from the drawings. These show in:

Fig. 1:

a partially cutaway perspective view of a gear unit, which is accommodated in a holder,

Fig. 2:

the gear unit according to Fig. 1 in a partially cutaway view without holder,

3:

a half-longitudinal view of the transmission unit according to Fig. 2 and

4:

a plan view of the gear unit shown in the aforementioned figures, from the figure, the interaction of the individual components is visible.

Embodiments of the invention

In the figures, the same components and components with the same function with the same reference numerals.

In Fig. 1 is a transmission unit 1 for an adjustment in a motor vehicle, in particular for a window lift drive, shown. The transmission unit 1 comprises a gear element 2 designed as an obliquely toothed driven gear (spur gear) made of plastic. This is driven by an electric motor (not shown), for example as shown in FIG DE 10 2005 012 938 A1 shown, powered. From the transmission element 2, the drive torque is transmitted to a coupling element 3. The coupling element 3 in turn is non-rotatably connected to an output element 4 (here: driven gear), via which the drive torque to an adjusting mechanism, for example to a cable drum, will pass.

Both the gear element 2 and the coupling element 3 are rotatably mounted on a rotationally fixed bearing axis 5, wherein the bearing axis 5 is integrally formed with a holding body 6. On the holding body 6, an annular lid member is fixed, which is a transmission element 2 receiving recess 8 in the holding body 6 closes. The cover element 7 is surmounted in the axial direction both by the bearing axle 5 and by the driven gear 6.

As is clear from the Fig. 1 and 2 shows, the coupling element has an inner ring portion 9, which is directly connected to the output element 4. Of the ring portion 9 protrude in two opposite radial directions, a first driver 10 and a second driver 11 away. The drivers 10, 11 cooperate with the transmission element 2 in such a way that the output torque is uniformly transmitted to the two carriers 10, 11 from the transmission element 2, which leads to a uniform loading of the coupling element 3 as a whole. The first driver 10 additionally cooperates with a load torque lock, which ensures that if a driven-side torque is introduced from the output element 4 or the coupling element 3 forth in a load torque lock 12, the latter blocks this output-side torque.

As is clear from the FIGS. 2 and 3 results, the load torque lock 12 comprises a spirally arranged wrap spring 13 which encloses in this embodiment radially outward designed as a drum cylinder member 14 (outer cylinder member). In the unassembled state, the inner diameter of the wrap spring 13 is (slightly) less than the outer diameter of the cylinder element 14. In the embodiment shown, the outer diameter of the cylinder element 14 is more than 2 cm.

In an alternative embodiment of the load torque lock 12, not shown, the cylinder element 14 is designed as an inner cylinder element (hollow cylinder) and the wrap spring 13 bears against the inner circumference of a cylinder element 14 designed in this way.

Like from the Fig. 1 to 3 it can be seen engages the first driver 10 in the radial direction in a first, circumferentially extending recess 15 within the transmission element and acts there depending on the direction of rotation with one of two pressure pieces 16, 17 together.

The functioning of the in the Fig. 1 to 3 shown load torque lock 12 is described below with reference to Fig. 4 explained.

In Fig. 4 It can be seen that in the circumferential direction and in the axial direction spaced apart ends 18, 19 of the spiral wrap spring 13 protrude in the radial direction outwardly from the cylinder member 14 away. In an alternative embodiment (not shown), in which the wrap spring 13 does not bear on the cylinder element 14 as shown, but on an inner circumference of the cylinder element 14, the ends 13, 19 protrude inward in the radial direction.

Each of the ends 18, 19 is associated with a pressure piece 16, 17, wherein the pressure pieces 16, 17 formed from thermoplastic shells are spaced apart in the circumferential direction and receive the ends 18, 19 of the wrap spring 13 in a form-fitting manner.

How to continue Fig. 4 it can be seen, the transmission element 2 has an outer guide contour 20 for the wrap spring 13, which prevents the wrap spring in a small angle range far radially from the cylinder element 14 lifts when from the first driver 10, in the circumferential direction between the two Pressure pieces 16, 17 or between the two ends 18, 19 is arranged, is pressed. Furthermore, it can be seen that the wrap spring 13 is arranged approximately in the region of half the radius of the transmission element 2. A small distance of the guide contour 20 to the outer diameter of the wrap 13 is important for a small angular play in the function.

Since the first driver 10 has the task of transmitting the drive torque from the transmission element 1 to the output, or in the reverse direction from the output to the pressure pieces 16, 17 of the wrap spring 13, the choice of materials takes place mainly under strength aspects. This particular because the first driver 10 must transmit the complete blocking torque at standstill of the transmission unit 1. Particularly preferred is therefore an embodiment of the first driver 10, preferably also of the second driver 11, more preferably also of the annular portion 9 of the coupling element 3 made of a fiber-reinforced plastic and / or metal. Alternatively, the first driver 10, in particular also the second driver 11, can be formed significantly larger, in particular when the angular ranges of the transmission element 1 reaching inwardly up to the wrap spring 13 are correspondingly reduced. In such, not shown embodiment, the first driver 10, preferably also the at least second driver 11 must take over the guiding function of the wrap spring 13 radially outside.

Through the use of elastomers in the region of contact points between the first driver 10 and the pressure pieces 16, 17, or in a non erfindungsggemäßen design without pressure piece on at least one end 18, 19 of the wrap 13 and / or stops of the transmission element 1 is a Damping in block trips possible, but it should be remembered that this increases the constructively necessary game at a reversal of direction.

In the transmission unit 1, a distinction is made between two operating modes, namely between "drive through" and "inhibition". When driving through the drive torque is transmitted from the transmission element 2 to the output. When inhibiting the drive from the output side. This output-side torque is delivered via the wrap spring 13 to ßdas rotatably arranged cylinder element, whereby the entire system is stationary.

First, the operating state "drive through" in the clockwise direction by means of Fig. 4 described. From a second stop 21 of the transmission element 2 pressure in the circumferential direction on a second stop 21 facing the second contact surface 22 of the second, in a second, circumferentially extending recess 23 of the transmission element 2 arranged driver 11 is exercised. Further, by a first stop 24 of the transmission element 1, which limits the first recess 15 in the circumferential direction, pressure on a first stop 24 facing contact surface 25 of the pressure member 16 is exerted, which adjusts the end 18 of the wrap 13 in the circumferential direction. The pressure piece 16 comes with a contact surface 25 facing away from the contact surface 26 in direct contact with a first contact surface 27 of the first driver 10. As a result, the output torque is evenly distributed from the transmission element 1 on the driver 10, 11, so that a uniform torque input into the coupling element 3 and thus in the output gear 4 results. The angular and gap dimensions are dimensioned such that an at least approximately uniform torque distribution results on the two drivers 10, 11.

In a counterclockwise "drive-through", a further second stop 28, which lies opposite the second stop 21 in the circumferential direction, comes to bear against a further second contact surface 29, which is arranged on a side of the second driver 11 spaced in the circumferential direction from the second contact surface 22. Further, another first stop 30, which limits the recess 15 at the opposite end of the first stop 24, comes to rest on a contact surface 31 of the right in the plane of the drawing pressure piece 17, which receives the end 19 of the wrap 13 in it. As a result, the pressure piece 17 is pressed in the plane of the drawing to the left with its contact surface 32 against a further first contact surface 33 of the first driver 10. In this case, the two first contact surfaces 27, 33 of the first driver seen in the circumferential direction are on opposite sides of the first driver 10. The drive torque is introduced from the second transmission element 2 consequently on both drivers 10, 11th

In the operating state "inhibition" of the drive from the output 4 from the rotatably connected to this coupling element 3. In a drive from the output side in a clockwise direction, the first driver 10 with its in the right half of the drawing located first contact surface 33 is pressed against the circumferentially opposite bearing surface 32 of the pressure piece 17, whereby the pressure piece 17 with the end 19 of the wrap spring 13 by a small angle of less than 6 °, preferably less than 4 °, twisted in the circumferential direction is, whereby the wrap spring 13 braced on the cylinder member 14, which in turn the output side torque is locked. Analogously, the blocking takes place counterclockwise. If the drive from the coupling element 3 forth in the counterclockwise direction, the first driver 10 is pressed with its first contact surface 27 against the opposite bearing surface 26 of the left in the drawing plane pressure piece 16, whereby this is moved with the end 18 of the wrap spring 13 in the circumferential direction to the left , As a result, the wrap spring 13 is also clamped about the cylinder element 14 - the output torque is thus blocked. With the embodiment shown, a minimum backlash of preferably less than 6 ° can be realized. This is particularly important in view of the realization of a pinch protection in a window lift drive, since the electric motor, not shown, should reverse as soon as possible after detecting a Einklemmfalles.

If elastomeric material is to be used in the load torque lock 12 for damping reasons, an embodiment is preferred in which the elastomeric material is preferably (only) arranged in the torque transmission chain transmission element (2) pressure pieces (16, 17) so that the elastomer material is not under load in the case of blocking , As a result, the amount of elastomeric material used can be reduced and / or the elastomeric material can be made softer. It is also possible to use elastomeric material in the Torque transfer chain second follower (11) -Griebeelement (2) to use.

Claims (11)

1. Transmission unit (1) for an adjustment drive of a motor vehicle, having a drive-side, rotatably arranged transmission element (2) by way of which a drive torque is transmittable to a first driver (10) of an output-side coupling element (3) of the transmission unit (1), and having a load-torque block (12) by way of which a torque introduced via the first driver (10) by the output-side, rotatably arranged coupling element (3) is blockable, wherein the load-torque block (12) has a wrap spring (13) which interacts with a cylinder element (14), arranged in a rotationally fixed manner, of the transmission unit (1) in order to block the torque, wherein the coupling element (3) has at least a second driver (11) interacting with the transmission element (2) in order to absorb a drive torque and the wrap spring (13) can be braced on the cylinder element (14) under the action of an output-side torque, and the wrap spring (13) has ends (18, 19) which project radially away from the cylinder element (14), characterized in that at least one of the ends (18, 19) of the wrap spring (13) is at least partially, preferably completely, accommodated in a pressure piece (16, 17), interacting with the first driver (10), of the transmission unit (1), wherein the pressure piece (16, 17) and the first driver (10) are arranged in a cutout (15) within the transmission element (2), wherein the transmission element (2) is in the form of a gearwheel.
2. Transmission unit (1) according to Claim 1, characterized in that the drivers (10, 11) are arranged in a regularly distributed manner in the circumferential direction of the transmission element (2).
3. Transmission unit (1) according to either of Claims 1 and 2, characterized in that the cylinder element (14) has a diameter of more than 2 cm interacting with the wrap spring (13).
4. Transmission unit (1) according to one of the preceding claims, characterized by the use of elastomers in the region of contact points between the first driver (10) and the at least one pressure piece (16, 17), as a result of which damping is possible during block movements.
5. Transmission unit (1) according to Claim 1, characterized in that the pressure piece (16, 17) is formed from at least two hot-pressed thermoplastic shells or is in the form of an injection-moulded plastics part.
6. Transmission unit (1) according to one of Claims 1 to 5, characterized in that the transmission element (2) has at least one first stop (24), bounding the cutout (15), with respect to a circumferential direction, said stop pressing one of the ends (18, 19), preferably accommodated in the pressure piece (16, 17), of the wrap spring (13) against the first driver (10) under the action of the drive torque such that the wrap spring (13), together with the transmission element (2) and the coupling element (3), rotates with respect to the cylinder element (14).
7. Transmission unit (1) according to Claim 6, characterized in that the transmission element (2) has at least one second stop (21) with respect to a circumferential direction, said stop being pressed against the second driver (11) of the coupling element (3) under the action of the drive torque, as a result of which the drive torque is transmitted to the coupling element (3).
8. Transmission unit (1) according to one of Claims 1 to 7, characterized in that the first driver (10) of the coupling element (3) is formed and/or arranged such that it rotates one of the ends (18, 19) of the wrap spring (13) with respect to the cylinder element (14) under the action of an output-side torque such that the wrap spring (13) braces against the cylinder element (14) and blocks the output-side torque.
9. Drive-transmission unit, comprising a transmission unit (1) according to one of the preceding claims, wherein the transmission element (2) is in the form of a gearwheel driven by an electric motor.
10. Drive-transmission unit according to Claim 9, characterized in that the coupling element (3) is connected in a torque-transmitting manner to an output element (4) or is formed integrally therewith.
11. Drive-transmission unit according to Claim 10, characterized in that the cutout (15) is provided as a guide for the at least one pressure piece (16, 17) in the circumferential direction, wherein the pressure piece (16, 17) is arranged in particular in a guide, formed as a curved contoured recess, within the transmission element (2).

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