Spring damper with two overload protection couplings; and drive train

Description

[0001] The invention relates to a spring damper for a motor vehicle drivetrain, preferably for a hybrid drivetrain of a motor vehicle, such as a car, truck, bus, or other commercial vehicle, comprising a primary part, a secondary part mounted for rotation relative to the primary part in a spring-damped manner, and a first overload protection clutch inserted between the secondary part and a hub element, which is permanently closed below a limit value of a torque to be transmitted and releases a relative rotation between the secondary part and the hub element above this limit value, at least in the event of a pulsed occurrence of the torque to be transmitted. Furthermore, the invention relates to a drivetrain comprising this spring damper.

[0002] Spring dampers of this type used in drivetrains are already well known in the art. For example, EP 2 765 331 A2 discloses a power transmission device with a damping component, a hysteresis generation component, and a speed limiting component.

[0003] Spring dampers with torque limiters in the form of overload protection clutches are already known, whereby the torque limiters can also be used in various positions. However, it has been found that the spring dampers used often have a relatively complex design with a large number of components and a relatively high mass inertia. Furthermore, the torque limiters are usually positioned as close as possible to the damper springs in order to adequately protect this area in the event of a torque pulse. However, this results in the component of the spring damper that is further connected to the transmission input shaft during operation having a relatively high mass moment of inertia, which in turn can lead to relatively high torque loads from the transmission input shaft and from there further into the transmission. The transmission input shaft and consequently the elements connected to it in the transmission, such as gears, etc.can therefore be overloaded in certain operating conditions.

[0004] It is therefore an object of the present invention to provide a spring damper which is as robust and durable as possible and which prevents overloading of a transmission connected during operation even when torque pulses occur.

[0005] This is achieved according to the invention in that a second overload protection clutch is inserted radially within the first overload protection clutch, acting between an output of the first overload protection clutch and the hub element. Consequently, a second overload protection clutch is now inserted in series with the previous first overload protection clutch. The second overload protection clutch is also designed such that it is permanently closed below a limit value of the torque to be transmitted and, above this limit value, releases a relative rotation between the output and the hub element, at least in the event of a pulsed occurrence of the torque to be transmitted, particularly during traction operation.

[0006] This has the advantage that one overload protection clutch, here the first overload protection clutch, is installed as close as possible to the damping mechanism of the spring damper, i.e., the damper springs, and another overload protection clutch, here the second overload protection clutch, is installed as close as possible to the transmission input shaft. This provides reliable protection for both the transmission input shaft and the damping mechanism of the spring damper. Another positive aspect is that the damper springs can be made even weaker and therefore more compact than previously known variants.

[0007] Further advantageous embodiments are claimed in the subclaims and explained in more detail below.

[0008] In order to further reduce the torque load, it is also considered advantageous if the secondary part has a flange element that is supported directly in the circumferential direction on a damper spring, which flange element in turn directly forms an input of the first overload protection clutch.

[0009] The overload protection clutches are also as simple to manufacture as possible if the output of the first overload protection clutch is formed by a multi-part carrier segment and at the same time forms an input of the second overload protection clutch.

[0010] It is also advantageous if the carrier segment has a first disk region and a second disk region connected to the first disk region, wherein the secondary part, preferably the flange element, is clamped axially between the first disk region and the second disk region. Further preferably, the first disk region and the second disk region are each formed as a sheet metal element / from a metal sheet. This allows the disk regions to be manufactured as simply as possible.

[0011] For the most effective operation of the first overload protection clutch, it is beneficial if the first disc area and the second disc area each accommodate a friction lining that is (directly) in contact with the secondary part.

[0012] Manufacturing is further simplified if both the first disc region and the second disc region are each formed by a single sheet metal element, which are axially spaced in the area of ​​the friction linings, accommodating the flange element, and are in contact with each other radially within the friction linings / are axially supported against each other, and are preferably directly connected to each other via a riveted joint. This enables efficient assembly and fastening of the two first and second disc regions to each other.

[0013] If the first disc area is additionally in contact with the primary part via a friction device, the damping effect of the spring damper is further improved.

[0014] Furthermore, it is advantageous if the carrier segment has a third disc region connected to the second disc region, with the hub element being axially clamped between the second disc region and the third disc region. Further preferably, the third disc region is also formed by a single sheet metal element that is directly connected to the sheet metal element of the second disc region. This also positively influences the assembly and construction of the second overload protection clutch.

[0015] In this regard, it is further advantageous if the second disc region and the third disc region or the sheets forming these second and third disc regions directly abut one another radially outside several friction linings of the second overload protection clutch and are fastened to one another there, preferably by riveting.

[0016] Accordingly, it is also advantageous if the second disc area and the third disc area each accommodate a friction lining resting on the hub element.

[0017] Furthermore, the invention relates to a drive train for a motor vehicle, with a spring damper according to the invention according to at least one of the previously described embodiments, wherein the primary part is connected to an output shaft of an engine and the hub element is connected to a transmission input shaft.

[0018] In other words, according to the invention, a spring damper, preferably in the form of a bow spring damper, is realized, which has a first, radially outer slip clutch (first overload protection clutch) arranged near the bow springs (damper springs), and a second, radially inner slip clutch (second overload protection clutch) arranged near the output shaft (i.e., near the transmission input shaft). Both slip clutches are connected in series and tuned so that both the bow spring flange (flange element) and the transmission input shaft can slip with a very low mass moment of inertia in the event of an impact.

[0019] The invention will now be explained in more detail below with reference to a figure.

[0020] It shows the only Fig. 1a longitudinal sectional view of a spring damper according to the invention according to a preferred embodiment, wherein the detailed structure of two overload protection clutches used can be clearly seen.

[0021] The Fig. 1 The spring damper 1 according to the invention shown in FIG. 1 is used in operation in a drive train 2 of a motor vehicle, here a hybrid drive train 2. The spring damper 1 is operatively inserted between an output shaft of an engine, preferably an internal combustion engine, (not shown further here for the sake of clarity), and a transmission input shaft of a transmission. The spring damper 1 thus serves to dampen certain torque peaks that occur between the engine and the transmission during operation.

[0022] The spring damper 1 after Fig. 1On the one hand, it has a housing-like primary part 3, which during operation is preferably directly connected in a rotationally fixed manner to the output shaft of the motor (not shown further for the sake of clarity). In addition to the primary part, the spring damper 1 also has a secondary part 4 that is spring-damped and rotatably mounted relative to the primary part 3. The primary part 3 and the secondary part 4 are supported relative to one another in the usual way by means of several damper springs 9, here in the form of arc springs, arranged distributed in the circumferential direction.

[0023] In addition to the resilient support of the primary part 3 to the secondary part 4 by the damper springs 9, an additional friction device 17 serves to generate the necessary damping effect, i.e., the conversion of kinetic energy into waste heat. The friction device 17 is effectively inserted between the primary part 3 and the secondary part 4 and inhibits their relative rotation.

[0024] The secondary part 4 is essentially formed by a flange element 10, which extends radially inward from an area in contact with the damper springs 9. A first overload protection clutch 6 is arranged / inserted directly on the flange element 10. The flange element 10 thus directly forms an input 11 of the first overload protection clutch 6 and is operatively connected to an output 8 of the first overload protection clutch 6 via two (first and second) friction linings 16a, 16b.The first overload protection clutch 6 is implemented as a conventional slip clutch, which is permanently closed below a certain limit value of a torque to be transmitted and thereby permanently connects the flange element 10 to the output 8 of the first overload protection clutch 6 in a rotationally fixed manner by frictional engagement and, when this limit value is exceeded, in particular when a torque pulse above the limit value occurs, releases / enables a relative rotation between the flange element 10 and the output 8 of the first overload protection clutch 6.

[0025] With regard to the output 8 of the first overload protection clutch 6, it is further shown that this is formed by a multi-part carrier segment 12. The carrier segment 12 has a first disc region 14 and a second disc region 15 firmly connected to it. The first disc region 14 and the second disc region 15 are guided towards one another radially within the first friction lining 16a and the second friction lining 16b, forming an axial shoulder 19 for each (first and second) disc region 14, 15, and are in contact with one another. The two first and second disc regions 14, 15 are connected to one another in this contact region via a first rivet 20.

[0026] Radially outside this first rivet 20, due to the formation of the shoulder 19, the two disc regions 14, 15 are again axially spaced from each other and axially accommodate the flange element 10 between them, with the respective friction lining 16a, 16b interposed. The flange element 10 is thus clamped between the two disc regions 14, 15.

[0027] With regard to the first disc region 14, it is also evident that it extends radially outside the friction linings 16a, 16b and forms a component of the friction device 17. The first disc region 14 is thus also in frictional contact with the primary part 3.

[0028] The carrier segment 12 simultaneously forms an input 13 of the second overload protection clutch 7, so that the second overload protection clutch 7 is arranged in series with the first overload protection clutch 6. On an axial side of the second disc region 15 facing away from the first disc region 14, a third disc region 18 is attached to this second disc region 15. The second disc region 15 is connected to the third disc region 18 via a further (second) rivet 21. In this embodiment, the second rivet 21 is arranged radially at the same height as the first and second friction linings 16a, 16b.

[0029] Radially within the second rivet 21, the second and third disc regions 15, 18 are axially spaced from one another by the respective configuration of the shoulder 19 and axially accommodate a hub element 5 or a flange region 22 of the hub element 5 between them. It should be noted that the first rivet 20 is located at the level of the third and fourth friction linings 16c, 16d in radial height.

[0030] The clamping of the flange region 22 between the second disc region 15 and the third disc region 18 takes place in a similar manner to the clamping of the flange element 10 between the first disc region 14 and the third disc region 18. Consequently, the flange region 22 is clamped axially between the second disc region 15 and the third disc region 18 with the interposition of a third friction lining 16c and a fourth friction lining 16d.

[0031] The function of the second overload protection clutch 7 is similar to that of the first overload protection clutch 6. When a certain limit value of the torque / torque pulse to be transmitted is exceeded, the second overload protection clutch 7 opens automatically, thus allowing rotation of the hub element 5 relative to the carrier segment 12 and consequently relative to the secondary part 4. Below this limit value, a rotationally fixed connection exists between the hub element 5 and the carrier segment 12. The hub element 5 thus forms an output 23 of the second overload protection clutch 7.

[0032] The third and fourth friction linings 16c, 16d are located radially within the first and second friction linings 16a, 16b. Furthermore, the friction lining group comprising the first and second friction linings 16a, 16b is arranged at least partially axially overlapping with the friction lining group comprising the third and fourth friction linings 16c, 16d.

[0033] With regard to the disc areas 14, 15, and 18, it should also be noted that these are each formed from a sheet metal. The shoulders 19 are preferably produced by cold forming.

[0034] In other words, the invention provides a damper (spring damper 1) with a dual torque limiter (first and second overload protection clutches 6, 7). There is a torque limiter (second overload protection clutch 7) that protects the transmission input shaft and another (first overload protection clutch 6) that protects the arc springs (damper springs 9).

[0035] The concept is as follows: The hub (hub element 5) serves as the rotating part in the torque limiter. It is placed between two clutch linings (third and fourth friction linings 16c, 16d) to ensure the slip function in the event of an impact. The clutch linings are mounted on the carrier plates (second disc area 15 and third disc area 18). The carrier plates are connected to each other via a rivet (second rivet 21). These parts form the (second) torque limiter, which serves to protect the transmission.

[0036] The carrier plate (second disc section 15) is connected to the carrier plate (first disc section 14) via a rivet (first rivet 20). The two clutch linings (first and second friction linings 16a, 16b) are mounted on the carrier plates (first disc section 14 and second disc section 15). The arc spring flange (flange element 10) is located between the two clutch linings (first and second friction linings 16a, 16b). This serves as a rotating part in the torque limiter, ensuring the slip function in the event of an impact. These parts form the (first) torque limiter, which protects the damper's arc springs.

[0037] Both torque limiters are connected to each other via the carrier plate (second disc section 15) and form one and the same part (rigid connection) during normal traction operation. Thus, during traction operation, the mass moment of inertia of parts 5, 18, 15, 20, 16c, 16d, 14, 21, 16a, 16b, and 10 acts on the transmission input shaft.

[0038] In the event of an impact (e.g., during emergency braking), the transmission input shaft and hub can slip on the transmission input shaft with a very low moment of inertia. At the same time, the arc spring flange can also slip separately on the arc spring with a very low moment of inertia. This concept allows for the design of optimal and soft arc spring characteristics with optimal protection. List of reference symbols

[0039] 1 Spring damper 2 Drive train 3 Primary part 4 Secondary part 5 Hub element 6 First overload protection clutch 7 Second overload protection clutch 8 Output of the first overload protection clutch 9 Damper element 10 Flange element 11 Input of the first overload protection clutch 12 Carrier segment 13 Input of the second overload protection clutch 14 First disc area 15 Second disc area 16 a First friction lining 16 b Second friction lining 16 c Third friction lining 16 d Fourth friction lining 17 Friction device 18 Third disc area 19 Shoulder 20 First rivet 21 Second rivet 22 Flange area 23 Output of the second overload protection clutch

Claims

1. A spring damper (1) for a motor vehicle powertrain (2), having a primary part (3), a secondary part (4) that is rotatably received relative to the primary part (3) in a spring-damped manner, and a first overload protection coupling (6) that is operatively inserted between the secondary part (4) and a hub element (5) and is permanently closed below a limit value of a torque to be transmitted and that, above this limit value, at least in the event of a sudden occurrence of the torque to be transmitted, releases a relative rotation between the secondary part (4) and the hub element (5), characterised in that a second overload protection coupling (7) is operatively inserted radially inside the first overload protection coupling (6) between an output (8) of the first overload protection coupling (6) and the hub element (5).

2. The spring damper (1) according to claim 1, characterised in that the secondary part (4) has a flange element (10) that is supported directly in the circumferential direction on a damper spring (9), which flange element (10) in turn directly forms an input (11) of the first overload protection coupling (6).

3. The spring damper (1) according to claim 1 or 2, characterised in that the output (8) of the first overload protection coupling (6) is formed by a multi-part support segment (12) and at the same time forms an input (13) of the second overload protection coupling (7).

4. The spring damper (1) according to any one of claims 1 to 3, characterised in that the support segment (12) has a first disc region (14) and a second disc region (15) connected to the first disc region (14), wherein the secondary part (4) is clamped axially between the first disc region (14) and the second disc region (15).

5. The spring damper (1) according to claim 4, characterised in that the first disc region (14) and the second disc region (15) each receive a friction lining (16a, 16b) resting on the secondary part (4).

6. The spring damper (1) according to claim 4 or 5, characterised in that the first disc region (14) is additionally in contact with the primary part (3) via a friction device (17).

7. The spring damper (1) according to any one of claims 4 to 6, characterised in that the support segment (12) has a third disc region (18) that is connected to the second disc region (15), wherein the hub element (5) is clamped axially between the second disc region (15) and the third disc region (18).

8. The spring damper (1) according to claim 7, characterised in that the second disc region (15) and the third disc region (18) each receive a friction lining (16c, 16d) resting on the hub element (5).

9. A powertrain (2) for a motor vehicle, having a spring damper (1) according to any one of claims 1 to 8, wherein the primary part (3) is connected to an output shaft of a motor and the hub element (5) is connected to a transmission input shaft.