Spring damper with two overload protection couplings and power train

Abstract

The present invention relates to a spring damper (1) for a drive train (2) of a motor vehicle, comprising a main part (3), an auxiliary part (4) rotatably received in a spring-cushioned manner relative to the main part (3), and a first overload protection coupling (6) operably inserted between the auxiliary part (4) and a hub element (5), the first overload protection coupling (6) being permanently closed when a torque below a threshold value is to be transmitted and releasing the relative rotation between the auxiliary part (4) and the hub element (5) when a torque above the threshold value is to be transmitted at least in abrupt cases, the second overload protection coupling (7) being operably inserted radially within the first overload protection coupling (6) between an output part (8) of the first overload protection coupling (6) and the hub element (5). The present invention further relates to a power train (2) comprising the spring damper (1).

Description

[Technical field]

[0001] The present invention relates to a spring damper for a drivetrain of a motor vehicle, such as a car, truck, bus or other commercial vehicle, preferably a hybrid drivetrain of a motor vehicle, comprising a main part, an auxiliary part rotatably received in a spring-cushioned manner relative to the main part, and a first overload protection coupling operatively inserted between the auxiliary part and a hub element, the first overload protection coupling being permanently closed when a torque below a threshold value is to be transmitted and releasing relative rotation between the auxiliary part and the hub element when a torque above the threshold value is to be transmitted, at least in abrupt cases. The present invention also relates to a drivetrain having this spring damper. [Background technology]

[0002] Spring dampers of the type of interest used in drive trains are already known in the prior art: for example, EP 2 765 331 A2 discloses a power transmission device having a damping component, a hysteresis generating component and a speed limiting component.

[0003] Thus, spring dampers with torque limiters in the form of overload protection couplings are known, which can also be used in different locations. However, the spring dampers used often turn out to have a complex structure, which has a large number of components and a relatively large inertial mass. The torque limiter is also usually arranged as close as possible to the damper spring in order to adequately protect this area in case of a torque impulse. However, this means that the components of the spring damper which are further connected to the transmission input shaft during operation have a relatively large mass moment of inertia, which can further result in relatively large torque loads on that part of the transmission input shaft and from there further into the transmission. Therefore, the transmission input shaft and, as a result, elements connected in the transmission, such as gears, can be overloaded in certain operating conditions. Summary of the Invention [Problem to be solved by the invention]

[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 the connected transmission from being overloaded during operation, even in the event of torque impulses. [Means for solving the problem]

[0005] According to the invention, this object is achieved in that the second overload coupling is operatively inserted radially into the first overload coupling between the output of the first overload coupling and the hub element, so that here the second overload coupling is inserted in series into the previous first overload coupling. Needless to say, the second overload coupling is also configured to be permanently closed when torques below a threshold value are to be transmitted and to release the relative rotation between the output and the hub element when torques above said threshold value are to be transmitted, at least in the case of sudden torques, in particular in traction operation.

[0006] This provides the advantage that one overload coupling, in this case the first overload coupling, is inserted as close as possible to the damping mechanism of the spring-damper, i.e. the damper spring, and another overload coupling, in this case the second overload coupling, is inserted as close as possible to the transmission input shaft, thereby providing reliable protection for both the transmission input shaft and the damping mechanism of the spring-damper. Another positive aspect is that the damper spring can be configured to be weaker and therefore more compact than damper springs of previously known types.

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

[0008] In order to further reduce the torque load, it is also considered advantageous if the auxiliary part has a flange element which is circumferentially supported directly on the damper spring and which flange element furthermore directly forms the input part of the first overload protection coupling.

[0009] If the output of the first overload coupling is formed by a multi-piece support segment which at the same time forms the input of the second overload coupling, the latter can also be manufactured as easily as possible.

[0010] It is also advantageous if the support segment has a first disk area and a second disk area connected to the first disk area, and the auxiliary part, preferably a flange element, is clamped axially between the first and second disk areas. Furthermore, the first and second disk areas are each preferably formed as sheet metal elements / formed from metal sheets. This allows the disk areas to be manufactured as easily as possible.

[0011] In order for the first overload protection coupling to be as effective as possible, it is advantageous if the first disc area and the second disc area each receive a friction lining which (directly) bears against the auxiliary part.

[0012] Manufacturing is further simplified if the first and second disc areas are each formed by a single sheet, axially spaced apart in the area of ​​the friction lining, receive the flange elements and are in radial contact with one another and / or axially supported by one another in the friction lining and are connected there directly to one another, preferably by a riveted connection, which allows an efficient assembly and an efficient attachment of the first and second disc areas to one another.

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

[0014] It is furthermore advantageous if the support segment has a third disc area connected to the second disc area and the hub element is axially clamped between the second and third disc areas. More preferably, the third disc area is also formed by a single seat which is directly connected to the seat of the second disc area. This also has a positive effect on the assembly and construction of the second overload protection coupling.

[0015] In this respect, it is further advantageous if the second disc area and the third disc area, or the sheets forming these second disc areas and the third disc areas, directly support each other radially outside the friction linings of the second overload protection coupling and are there attached to each other, preferably by a riveted connection.

[0016] It is therefore also advantageous if the second and third disc areas each receive a friction lining supporting a hub element.

[0017] Furthermore, the present invention relates to a drivetrain for a motor vehicle having the inventive spring damper according to at least one of the above-mentioned embodiments, the main part being connected to the output shaft of a prime mover and the hub element being connected to a transmission input shaft.

[0018] In other words, a spring damper, preferably a bow-shaped spring damper, is implemented according to the invention as described above, which has a first radially outer slip coupling (first overload protection coupling) located close to the bow spring (damper spring) and a second radially inner slip coupling (second overload protection coupling) located close to the output shaft (i.e. close to the transmission input shaft), both slip couplings being connected in series and adjusted so that the bow spring flange (flange element) and the transmission input shaft can slip in each case with a very small mass moment of inertia in the event of an impact.

[0019] In the following, the invention is explained in more detail by means of drawings. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1, the only figure, shows a longitudinal section of a spring damper according to a preferred exemplary embodiment of the invention, in which the detailed structure of the two inserted overload protection couplings is clearly visible. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] A spring damper 1 according to the invention shown in Figure 1 is inserted in operation in a drive train 2 of a motor vehicle, in this case a hybrid drive train 2, shown in principle. The spring damper 1 is operatively inserted between the output shaft of a prime mover, preferably an internal combustion engine (not shown for clarity of the figure), and a transmission input shaft of the transmission. As a result, the spring damper 1 serves to damp some torque peaks that occur between the prime mover and the transmission during operation.

[0022] On the other hand, the spring damper 1 according to Fig. 1 has a housing as a main part 3, which in operation is preferably directly and non-rotatably connected to the output shaft of a prime mover (not shown for the sake of clarity of the drawing). In addition to the main part, the spring damper 1 also has an auxiliary part 4 which is received in a spring-cushioned manner so as to be rotatable relative to the main part 3. The main part 3 and the auxiliary part 4 are supported in a spring-cushioned manner relative to one another by several damper springs 9, here in the form of bow springs, which are arranged distributed in the circumferential direction.

[0023] In addition to the elastic support of the main part 3 against the auxiliary part 4 by the damper spring 9, an additional friction device 17 serves to generate the necessary damping effect, i.e. to convert kinetic energy into waste heat. The friction device 17 is operatively interposed between the main part 3 and the auxiliary part 4 and has the effect of preventing them from rotating relative to each other.

[0024] The auxiliary part 4 is substantially formed by a flange element 10 extending radially inwards away from the area in contact with the damper spring 9. The first overload coupling 6 is placed / inserted directly on the flange element 10. The flange element 10 thus directly forms the input part 11 of the first overload coupling 6 and is operatively connected to the output part 8 of the first overload coupling 6 via two (first and second) friction linings 16a, 16b. The first overload coupling 6 is implemented as a conventional slip coupling, which is permanently closed when a certain torque below a threshold value is to be transmitted and in this state permanently connects the flange element 10 to the output part 8 of the first overload coupling 6 in a non-rotatable manner by frictional engagement, while releasing / allowing relative rotation between the flange element 10 and the output part 8 of the first overload coupling 6 when this threshold value is exceeded, in particular in the event of a torque impulse above this threshold value.

[0025] It is further shown that the output part 8 of the first overload protection coupling 6 is also formed by a multi-piece support segment 12. The support segment 12 has a first disc area 14 and a second disc area 15 fixedly connected to the first disc area 14. The first disc area 14 and the second disc area 15 are guided radially inside the first friction lining 16a and the second friction lining 16b and are in contact with each other forming an axial shoulder 19 for each (first and second) disc area 14, 15. The two first disc areas 14 and the second disc areas 15 are connected together in this contact area by a first rivet connection 20.

[0026] Radially outside this first rivet connection 20, through the formation of a shoulder 19, two disk areas 14, 15 are further axially spaced apart from one another and axially receive between them the flange element 10 with the respective friction linings 16a, 16b in between. The flange element 10 is thus clamped between the two disk areas 14 and 15.

[0027] It is also evident that the first disc region 14 is radially outwardly continuous with 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 main part 3.

[0028] The support segment 12 also forms the input 13 of the second overload coupling 7, so that the second overload coupling 7 is arranged in series with the first overload coupling 6. On the axial side of the second disc area 15 facing away from the first disc area 14, a third disc area 18 is attached to this second disc area 15 for this purpose. The second disc area 15 is connected to the third disc area 18 by a further (second) rivet connection 21. In this embodiment, the second rivet connection 21 is arranged radially at the same level as the first and second friction linings 16a, 16b.

[0029] Radially inside the second rivet connection 21, the second and third disk areas 15, 18 are axially spaced apart from one another by the formation of respective shoulders 19 and axially receive between them the hub element 5 or a flange area 22 of the hub element 5, respectively. It should be noted that the first rivet connection 20 is located radially at the level of the third and fourth friction linings 16c, 16d.

[0030] In a manner similar to the way that the flange element 10 is clamped between the first disc area 14 and the third disc area 18, the flange area 22 is clamped between the second disc area 15 and the third disc area 18. As a result, the flange area 22 is clamped axially between the second disc area 15 and the third disc area 18 in a position intermediate the third friction lining 16c and the fourth friction lining 16d.

[0031] The function of the second overload coupling 7 is similar to that of the first overload coupling 6. When a certain threshold of the torque / torque impulse to be transmitted is exceeded, the second overload coupling 7 automatically opens, thereby allowing the hub element 5 to rotate relative to the support segment 12 and therefore relative to the auxiliary part 4. On the other hand, below this threshold a non-rotatable connection is established between the hub element 5 and the support segment 12. The hub element 5 consequently forms the output part 23 of the second overload coupling 7.

[0032] The third friction lining 16c and the fourth friction lining 16d are located radially inside the first friction lining 16a and the second friction lining 16b, and the friction lining assembly including the first friction lining 16a and the second friction lining 16b is arranged to at least partially overlap in the axial direction with the friction lining assembly including the third friction lining 16c and the fourth friction lining 16d.

[0033] It should be noted that the disk regions 14, 15, 18 are each formed from a metal sheet. In this regard, the shoulder portion 19 is preferably manufactured by means of cold forming.

[0034] In other words, according to the invention a damper (spring damper 1) is implemented which is equipped with a double torque limiter (first overload coupling 6 and second overload coupling 7). In this case there is one torque limiter (second overload coupling 7) which protects the transmission input shaft and another torque limiter (first overload coupling 6) which protects the bow spring (damper spring 9).

[0035] The concept is structured as follows: a hub (hub element 5) serves as the rotating part in the torque limiter. It is arranged between two coupling linings (third friction lining 16c and fourth friction lining 16d) which ensure the slip function in case of an impact. The coupling linings are mounted on support sheets (second disc area 15 and third disc area 18). The support sheets are connected to each other by a riveted connection (second riveted connection 21). These parts form the above-mentioned (second) torque limiter, which serves to protect the transmission.

[0036] The support sheet (second disk area 15) is connected to the support sheet (first disk area 14) by a rivet connection (first rivet connection 20). Two coupling linings (first friction lining 16a and second friction lining 16b) are mounted on the support sheets (first disk area 14 and second disk area 15). A bow spring flange (flange element 10) is located between the two coupling linings (first friction lining 16a and second friction lining 16b). The bow spring flange serves as a rotating part in the torque limiter to ensure that the slip function can be activated in the event of an impact. These parts form the (first) torque limiter, which protects the bow spring of the damper.

[0037] Both torque limiters are connected to each other via a support seat (second disc area 15) and form an integral part (rigid connection) in normal towing operation. Thus, in towing operation, the mass moment of inertia of parts 5, 18, 15, 20, 16c, 16d, 14, 21, 16a, 16b, 10 acts on the transmission input shaft.

[0038] In the unlikely event of an impact (e.g. during heavy braking), the transmission input shaft and hub are able to slip with a very low mass moment of inertia on the transmission input shaft. In parallel, the bow spring flanges are also able to slip separately with a very low mass moment of inertia on the bow spring. This concept allows configuring the bow spring characteristics to be optimally flexible and with optimal protection. [Explanation of symbols]

[0039] 1 Spring damper 2. Drivetrain 3 Main parts 4 Auxiliary part 5 Hub Elements 6 First overload protection coupling 7 Second overload protection coupling 8 Output of the first overload protection coupling 9 Damper elements 10 Flange elements 11 Input of first overload protection coupling 12 Support Segments 13 Input of second overload protection coupling 14 First Disk Area 15 Secondary Disk Space 16a First friction lining 16b Second Friction Lining 16c Third Friction Lining 16d Fourth Friction Lining 17 Friction device 18 Third Disk Space 19 Shoulder section 20 First rivet connection 21 Second riveted connection 22 Flange Area 23 Output of second overload protection coupling

Claims

1. 1. A spring damper (1) for a drive train (2) of a motor vehicle, comprising a main part (3), an auxiliary part (4) rotatably received in a spring-cushioned manner on the main part (3), and a first overload protection coupling (6) operably inserted between the auxiliary part (4) and a hub element (5), the first overload protection coupling (6) being permanently closed when a torque below a threshold value is to be transmitted and releasing relative rotation between the auxiliary part (4) and the hub element (5) when a torque above the threshold value is to be transmitted, at least in abrupt cases, the first overload protection coupling (6) being permanently closed when a torque below a threshold value is to be transmitted and releasing relative rotation between the auxiliary part (4) and the hub element (5),

2. 2. A spring damper (1) according to claim 1, characterized in that the auxiliary part (4) has a flange element (10) supported directly in the circumferential direction on the damper spring (9), said flange element (10) further directly forming an input part (11) of the first overload protection coupling (6).

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

4. 4. The spring damper (1) according to claim 3, characterized in that the support segment (12) has a first disk area (14) and a second disk area (15) connected to the first disk area (14), and the auxiliary part (4) is clamped axially between the first disk area (14) and the second disk area (15).

5. 5. A spring damper (1) according to claim 4, characterized in that the first disc area (14) and the second disc area (15) each receive a friction lining (16a, 16b) bearing against the auxiliary part (4).

6. A spring damper (1) according to claim 4 or 5, characterised in that the first disc area (14) is also in contact with the main part (3) via a friction device (17).

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

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

9. A drivetrain (2) for a motor vehicle, comprising a spring damper (1) according to any one of claims 1 to 8, the main part (3) being connected to an output shaft of a prime mover and the hub element (5) being connected to a transmission input shaft.

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