Torsional vibration damper

Abstract

Torsional vibration damper (1) with an input part (2) rotatable about an axis of rotation (d) and an output part (3) rotatable about the axis of rotation (d) against the action of a spring device (4), wherein the input part (2) comprises a radially inner mounting part (12), disc parts (7) forming an annular chamber (8) for the spring device (4) on the radial outside, and a drive disc (10) arranged radially between and connecting these, and wherein the drive disc (10) is riveted to the mounting part (12), wherein riveting fingers (13) are arranged on the drive disc (10) distributed around its circumference, each of which extends axially through openings (14) of the mounting part (12) and is formed into windows (15) of the mounting part (12), characterized in thatthat the crimping fingers (13) are aligned and formed into the windows (15) arranged radially inside the openings (14) by rotating the drive disc (10) relative to the fastening part (12) about the axis of rotation (d).

Description

[0001] The invention relates to a torsional vibration damper with an input part rotatable about an axis of rotation and an output part rotatable about the axis of rotation to a limited extent against the action of a spring device, wherein the input part includes a radially inner mounting part, disc parts forming an annular chamber for the spring device on the radial outside, and a drive disc arranged radially between and connecting these.

[0002] Torsional vibration dampers are used, particularly in drive trains with internal combustion engines that exhibit torsional vibration, for torsional vibration isolation. For this purpose, an input part of the torsional vibration damper is connected to the crankshaft of the internal combustion engine by means of fastening bolts. The applied torque is transmitted from the input part to an output part via a spring assembly, whereby the spring assembly and, if applicable, superimposed friction elements dampen the torsional vibrations of the applied torque. For example, a torsional vibration damper of this type is known from German patent application DE 10 2017 117 526 A1. It is in the form of a dual-mass flywheel with an input part having a primary flywheel and an output part with a secondary flywheel that is rotatable to a limited extent relative to the input part, against the action of a spring assembly.The input assembly contains an axially elastic drive plate, a so-called flexplate, formed from several stacked sheet metal discs. This flexplate dampens axial vibrations, wobble vibrations, and / or shielding vibrations of the crankshaft. The drive plate is riveted radially to an annular chamber formed from two disc sections. Radially, it forms a unit consisting of a mounting part facing the crankshaft, the drive plate, and a bearing plate for the mounting bolts. To create a sub-assembly, the mounting part, the drive plate, and the bearing plate are typically pre-riveted together until the three components are finally fastened to the crankshaft using the mounting bolts.

[0003] German patent DE 100 02 259 A1 discloses a torsional vibration damper with an input part rotatable about an axis of rotation and an output part rotatable about the same axis, limited by the action of a spring assembly. The input part has a mounting hub radially on its inner surface, which sits on a needle sleeve. A disc section extends radially outward from the needle sleeve and, together with a cover of the torsional vibration damper, forms an annular chamber. A spring assembly is housed within the annular chamber. The mounting hub and the disc section are connected by rivets distributed around the circumference. Each rivet connection consists of a lug on the disc section and extends axially through an opening in the mounting hub. The lug is crimped at its end.

[0004] DE 10 2010 014 677 A1 discloses a torsional vibration damper in which the connection between the mounting hub and the disc part is formed by rivets.

[0005] German patent DE 10 2010 022 253 A1 discloses a torsional vibration damper whose mounting hub and annular chamber are connected via a three-layer flexible plate. The mounting hub and the plate are held together radially on the inside by means of the crankshaft bolt. The plate and the disc part are fastened together by means of rivet connections.

[0006] The object of the invention is the further development of a torsional vibration damper of the generic type. In particular, the object of the invention is to reduce the clamping length of the input part at the mounting openings.

[0007] The problem is solved by the subject matter of claim 1. The dependent claims describe advantageous embodiments of the subject matter of claim 1.

[0008] The proposed torsional vibration damper serves to isolate torsional vibrations, particularly in the powertrain of a motor vehicle with a torsional-vibrational internal combustion engine. The powertrain can also be hybrid, incorporating an electric motor for alternative and / or supplementary propulsion of the vehicle. To further enhance torsional vibration isolation, at least one centrifugal pendulum can be incorporated on the input and / or output side.

[0009] The torsional vibration damper comprises an input section rotatable about an axis of rotation and an output section rotatable about the same axis, but with limited rotational movement against the force of a spring assembly. The spring assembly can consist of arc springs distributed around the circumference or of nested arc spring assemblies. Multi-stage characteristics of the torsional vibration damper can be achieved by using arc springs of varying lengths within an arc spring assembly. The torsional vibration damper can be designed as a dual-mass flywheel, with a primary flywheel mass assigned to the input section and a secondary flywheel mass to the output section. The spring assembly is housed in an annular chamber, preferably formed by the input section, and may optionally be operated within a tightly sealed annular chamber lubricated by a lubricant.The annular chamber can be formed from several, preferably two, disc parts, which may have embossings for the input-side actuation of the spring device.

[0010] The output section can be rotatably mounted relative to the input section by means of a bearing, for example, a rolling or sliding bearing, wherein the secondary flywheel mass forms a counter-pressure plate for a friction clutch and can have or accommodate a clutch pressure plate. Alternatively, the output section can include an output hub which is rotationally connected to a subsequent drivetrain component, for example, a dual clutch, a transmission input shaft, or the like, by means of an internal toothing. For the output-side actuation, the output section includes, for example, a disc-shaped flange section which has radially outwardly extending arms that engage between arc springs distributed around the circumference.The flange part can form a pendulum mass carrier of a centrifugal pendulum, on which pendulum masses are mounted on both sides in a way that allows them to oscillate in the centrifugal field of the torsional vibration damper rotating around the axis of rotation.

[0011] The input section of the proposed torsional vibration damper is split and comprises a radially inner mounting element, an annular chamber formed from disc segments on the radially outer side, and a drive plate arranged radially between and connecting the mounting element and the annular chamber. To reduce the clamping length, particularly in the area where the torsional vibration damper is mounted on a crankshaft, the drive plate is riveted to the mounting element. This riveting eliminates the need for pre-riveting. Furthermore, a two-layer assembly of mounting element and drive plate can be used, in which the drive plate forms the contact surface on the crankshaft, and the mounting element serves as a bearing plate for the mounting screws passing through the mounting holes of both the mounting element and the drive plate. For this purpose, the mounting element can be hardened to a high degree.The drive plate, on the other hand, can have a medium hardness. To rivet the drive plate to the fastening part, riveting fingers are arranged around the circumference of the drive plate. These riveting fingers extend axially through openings in the fastening part and are formed into windows in the fastening part. The riveting fingers can be essentially radial in shape, with the windows arranged radially within each opening.

[0012] The caulking is achieved by aligning the caulking fingers, after they have passed through the openings, with the radially arranged windows within the openings by rotating the drive disc relative to the fastening part around its axis of rotation. This rotation of the drive disc after the caulking fingers have been inserted into the openings of the fastening part can, for example, be clockwise. By caulking the caulking fingers into the windows, the drive disc is supported by the caulking fingers on radially arranged, freestanding webs located between the openings and the windows.

[0013] The torsional vibration damper is attached to a crankshaft using mounting holes and through-bolts that are screwed into the crankshaft. For this purpose, the drive plate and the mounting part have aligned mounting holes after crimping. To save installation space, the openings and windows with the mounting holes can be arranged alternately around the circumference. This alternating arrangement can be regular, with a number of crimping fingers and corresponding openings and windows corresponding to the number of mounting holes, or irregular, with a larger or smaller number of crimping fingers. The openings, windows, and mounting holes can be arranged on similar or identical pitch circles.

[0014] In a design where the output part is mounted opposite the input part, a bearing boss can be connected to the mounting part in separate parts or, particularly advantageously, as a single piece. In a single-piece design, the bearing boss can be integrally formed with the mounting part. A bearing surface for a plain bearing or a rolling bearing, such as a deep groove ball bearing or the like, can be formed by tooling or subsequently machined.

[0015] The drive plate can be designed, for example, as a rigid sheet metal disc, with a thickness between 4 mm and 8 mm. Alternatively, the drive plate can be designed from at least one axially elastic sheet metal disc. For example, a single sheet metal disc designed as a flexplate can have a thickness between 2 mm and 3 mm. Alternatively, two or more thin sheet metal discs or leaf spring elements arranged around the circumference can be stacked together to form an axially elastic drive plate. In this case, one, several, or all of these sheet metal discs or leaf springs in such a stack can each form a crimping finger.

[0016] The invention is described in relation to the invention described in the Fig. The embodiments shown in points 1 to 5 are explained in more detail below. These show: Fig. 1. The upper part of a torsional vibration damper arranged around a rotational axis in partial section in fully assembled state, Fig. 2 a sectional detail of the torsional vibration damper of the Fig. 1 in the area of ​​caulking, Fig. 3 a partial view of the inlet part of the torsional vibration damper of the Fig. 1 and Fig. 2, Fig. 4 the upper part of the inlet part of the torsional vibration damper of the Fig. 1 to 3 on average before caulking and Fig. 5 a partial view of the inlet part of the torsional vibration damper of the Fig. 1 to 4 before the final joining of the fastening part and the drive plate.

[0017] The Fig. Figure 1 shows the upper half of the torsional vibration damper 1, which is rotatable about the axis of rotation d, in partial section, with the input part 2 and the output part 3, only partially shown, which is rotatable about the axis of rotation d against the action of the spring assembly 4 formed by the arc springs 17, 18 distributed around the circumference, with the output hub 5 and the centrifugal pendulum 6 arranged radially inside the spring assembly 4. The centrifugal pendulum 6 contains the flange part 19, which acts on the arc springs 17, 18 on the output side by means of the radially extended arms 20 on the outer radial side and supports the pendulum masses 21 on both sides by means of pendulum bearings (not shown) so that they can oscillate.

[0018] The inlet part 2 contains, radially outward, the annular chamber 8 formed from the disc part 7 and another disc part (not shown) welded to it, wherein the disc parts, for example by means of embossing, actuate the bow springs 17, 18 on the inlet side. The annular chamber 8 is connected to the drive disc 10 by means of rivets 9 distributed around its circumference. The drive disc 10 is axially elastic. Radially inward, the drive disc 10 is connected to the fastening part 12 by means of the rivet 11.

[0019] To form the riveting connection, the drive disc 10 has riveting fingers 13 distributed around its circumference, projecting from radially outside to radially inside. These riveting fingers extend into openings 14 in the fastening part 12 and are formed into windows 15 provided radially inside the openings 14 in the fastening part 12. The riveting 11 creates a subassembly between the drive disc 10 with the disc parts 7 forming the annular chamber 8, the spring assembly 4, the centrifugal pendulum 6, and the fastening part 12. The torque-resistant connection between the fastening part 12 and the drive disc 10 is only formed after the torsional vibration damper 1 has been attached to the crankshaft of the internal combustion engine. For this purpose, the drive disc 10 and the fastening part 12, in the riveted state, have aligned mounting holes for the fastening screws 16.The drive plate 10 is clamped against the crankshaft by means of the fastening screws 16. The mounting part 12 serves as a screw head bearing for the fastening screws 16 and is accordingly hardened. This arrangement allows for a two-layer mounting of the torsional vibration damper 1 to the crankshaft, thus enabling a short clamping length S of the fastening screws 16 while maintaining sufficient strength.

[0020] The Fig. Figure 2 shows a detail of the torsional vibration damper 1 arranged around the axis of rotation d. Fig. 1 in section in the area of ​​the caulking 11 in the joined and caulked state. The caulking fingers 13 of the drive disc 10 extend through the radially outer openings 14 and are formed into the windows 15 arranged radially within the openings 14. The drive disc 10 is supported by the caulking fingers 13 on the webs 22 arranged between the openings 14 and the windows 15 and is securely held on the fastening part 12. The torque-resistant connection of the fastening part 12 and the drive disc 10 to the crankshaft is achieved by means of the fastening screws 16. Fig. Figure 3 shows a partial view of the inlet part 2 in the radially inner area of ​​the riveting 11 in the joined state of the drive disc 10 with the fastening part 12. On the pitch circle 23 of the fastening openings 24 distributed around the circumference for the fastening screws 16 ( Fig. 1) Openings 14 are provided in the fastening part in the circumferential direction between these. The openings 14 have a first radially widened part 25, which allows complete passage of the crimping fingers 13. The second part 26 of the openings 14, adjacent in the circumferential direction, is radially shortened inwards and forms the web 22 with respect to the windows 15 arranged radially inside the second part 26 of the openings 14 ( Fig. 2) out.

[0021] The joining process of the drive disc 10 to the fastening part is carried out by inserting the crimping fingers 13 through the first part 25 of the openings 14, twisting the drive disc 10 and forming the crimping fingers 13 into the windows 15.

[0022] The Fig. Figure 4 shows the upper part of the input part 2 arranged around the axis of rotation d during the joining process of the riveting 11. In the stage shown, the riveting fingers 13 of the drive disc 10 are inserted through the openings 14 of the fastening part 12, and the drive disc 10 and the fastening part are axially aligned flush. The riveting fingers have not yet been formed.

[0023] The Fig. 5 shows this in Fig.Figure 4 shows the stage of the joining process of the caulking 11 by means of a partial view of the input part 2. The caulking fingers 13 of the drive disc 10 extend axially into the first part 25 of the openings 14. In the next step, the drive disc 10 is rotated in the direction of arrow 27 until the mounting openings 24 of the drive disc 10 and the mounting part 12 are aligned. In doing so, the caulking fingers 13 overlap the webs 22 between the second part of the openings 14 and the windows 15. In the final step, the ends of the caulking fingers 13 are formed into the windows. Reference symbol list 1 torsional vibration damper 2 Entrance section 3 Initial part 4 Spring assembly 5 Output hub 6 Centrifugal pendulums 7 disc section 8 ring chamber 9 rivets 10 Drive plate 11. Caulking 12 Mounting part 13 crimping fingers 14 Opening 15 windows 16 fastening screw 17 Bow feather 18 Bow feather 19 Flange part 20 Arm 21 Pendulum masses 22 Bridge 23 subcircle 24 Mounting opening Part 25 Part 26 27 Arrow d axis of rotation S clamping length

Claims

[1] Torsional vibration damper (1) with an input part (2) rotatable about an axis of rotation (d) and an output part (3) rotatable about the axis of rotation (d) against the action of a spring device (4), wherein the input part (2) comprises a radially inner mounting part (12), disc parts (7) forming an annular chamber (8) for the spring device (4) on the radial outside, and a drive disc (10) arranged radially between and connecting these, and wherein the drive disc (10) is riveted to the mounting part (12), wherein riveting fingers (13) are arranged on the drive disc (10) distributed around its circumference, each of which extends axially through openings (14) of the mounting part (12) and is formed into windows (15) of the mounting part (12), characterized by, that the crimping fingers (13) are aligned and formed into the windows (15) arranged radially inside the openings (14) by rotating the drive disc (10) relative to the fastening part (12) about the axis of rotation (d). [2] Torsional vibration damper (1) according to claim 1, characterized by , that the drive disc (10) is supported by means of the crimping fingers (13) on webs (22) arranged radially between the openings (14) and the windows (15). [3] Torsional vibration damper (1) according to one of claims 1 to 2, characterized by , that the drive plate (10) and the fastening part (12) form aligned fastening openings (24) for fastening the torsional vibration damper (1) to a crankshaft of an internal combustion engine after riveting. [4] Torsional vibration damper (1) according to claim 3, characterized by, that the fastening part (12) serves as a support washer for the fastening screws (16) passing through the fastening openings (24). [5] Torsional vibration damper (1) according to claim 3 or 4, characterized by , that the openings (14) and windows (15) with the fastening openings (24) are arranged alternately around the circumference. [6] Torsional vibration damper according to any one of claims 1 to 5, characterized by that the fastening part has an axially extended bearing dome to form a bearing between the input part and the output part. [7] Torsional vibration damper according to any one of claims 1 to 6, characterized by that the drive disc is designed as a rigid sheet metal disc. [8] Torsional vibration damper (1) according to any one of claims 1 to 7, characterized by , that the drive disc (10) is formed from at least one axially elastic sheet metal disc.

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