Construction kit comprising a flywheel and a damper for transferring torque from an internal combustion engine to a downstream gearbox

Abstract

The invention relates to a construction kit (1) comprising a one-piece flywheel (2), which can be screw-connected directly to a crankshaft of an internal combustion engine, and a damper (3) for transferring torque from the internal combustion engine to a downstream gearbox of a vehicle drive train, wherein there are windows (5) in the flywheel (2), at least one spring (6) of the damper (3) at least partially engaging in each of the windows. The invention also relates to a vehicle drive train comprising an internal combustion engine, a gearbox and a construction kit of this kind arranged / interposed between them.

Description

[0001] Flywheel and damper kit for transmitting torque from an internal combustion engine to a downstream transmission

[0002] The invention relates to a kit consisting of a flywheel and a damper for transmitting torque from an internal combustion engine to a downstream transmission. The term "damper" is used here, in particular, as a shortened form for "torsional vibration damper."

[0003] A large number of such kits are already known from the prior art, for example from DE 10 2004 016 960 A1, which discloses a flywheel assembly. The subject matter therein relates to a flywheel damper to which torque is transmitted from a crankshaft of an internal combustion engine. The flywheel damper comprises a second flywheel assembly, a damper mechanism, and a support plate. The damper mechanism connects the second flywheel assembly to the crankshaft in a direction of rotation. The support plate is fastened to the crankshaft and supports the second flywheel assembly of a crankshaft. The support plate has an axial extension which can be fastened to and detached from the second flywheel assembly in the axial direction.

[0004] Currently, flywheels made of cast material are often used. However, these have cost disadvantages. In particular, solutions consisting of a separate cast flywheel and a damper are often too expensive. Furthermore, it has been shown that the installation space is not used efficiently.

[0005] It is the object of the present invention to eliminate these and other disadvantages of the prior art. In particular, a durable, space-efficient and cost-effective combination of flywheel and damper should be usable for use in particular in hybrid vehicle drive trains in passenger cars, commercial vehicles or other land-based vehicles. This object is achieved according to the invention by a kit comprising a one-piece flywheel that can be screwed directly to a crankshaft of an internal combustion engine and a damper for transmitting torque from the internal combustion engine to a downstream transmission of a vehicle drive train according to claim 1, wherein windows are provided in the flywheel, into each of which at least one spring of the damper at least partially engages.

[0006] This way, the compression springs engage directly with the flywheel on at least one side, allowing for more efficient use of axial space. Axial space is saved by nesting the flywheel with the damper. Especially in advanced / progressive / more advanced powertrains, it is now possible to build shorter axially.

[0007] The presented design enables considerable cost savings, particularly by avoiding cast material and using sheet metal components, for example by using non-cutting manufacturing processes.

[0008] Advantageous embodiments are claimed in the subclaims and are explained in more detail below.

[0009] It is therefore advantageous if the spring only engages in the window (but not, and in particular not completely, through it) or even engages through the window. The window can therefore be designed as a through-hole or as a blind hole. In principle, it is conceivable for all windows to be of the same type, or for them to have alternating designs, for example, with blind holes and through-holes alternating around the circumference. If the window is designed as a through-hole, it is possible for the spring to engage only to a limited extent in the window or even for the spring to engage through the window from one end face to the other during installation. However, merely engaging is easier to install. Reaching through, however, saves even more axial installation space.One can imagine that it might be desirable for the spring to extend from one end face into the window exactly until just before the opposite end face.

[0010] The precision of the assembly during operation is increased when the compression spring rests directly on the flywheel. Additionally or alternatively, it is conceivable to use stop elements such as end caps on an intermediate layer to minimize noise and reduce wear.

[0011] In this context, it is advantageous if the compression spring is designed as a straight spring, especially a helical spring, preferably with or without end caps. The assembly of end caps, in particular, can be carried out efficiently, even in automated production.

[0012] For assembly, it is also advantageous if the end cap is designed as a cup, sleeve, or pot, particularly made of plastic or metal, such as steel. Metal cups, preferably made of steel, are particularly suitable for commercial vehicles. However, the use of plastic reduces the overall weight, which is particularly beneficial for CO2 emissions.

[0013] It has proven effective for the spring to engage the window by at least 1 / 3, 1 / 2, or 2 / 3 of the thickness of the wire from which the spring is made. This ensures that at least sufficient flywheel material is in contact with sufficient spring material in the event of a stop, i.e., when torque is transmitted. This increases reliability.

[0014] If a torque limiter is installed downstream of the damper in the torque curve from the internal combustion engine to the transmission, additional protection against breakage of individual components can be provided.

[0015] It has also proven advantageous if a roof / sash protrudes from the radial plane of a counterpane in the area of ​​the window. This sash can then be used to ensure good contact of the compression springs or cups. It has also proven effective if the sash is located at the level of the radially outer end of the window in the flywheel and / or is angled, as this allows the sash to exert a retaining effect on the compression springs if necessary. The window itself can be angled / stamped, particularly at its radially outer edge.

[0016] It is advantageous if the flywheel is made of sheet metal. Cast material is also possible, of course. However, sheet metal has the advantage of being easier to manufacture and higher density than cast material. This cleverly enables production without the need for tools. This allows for higher production volumes at lower production costs.

[0017] It is advantageous if the flywheel has a doubled section on the radial outer side or is folded radially outward. This contributes to the efficient use of the moment of inertia.

[0018] It is advantageous if the torque limiter has a torque transfer plate clamped between two friction linings. This makes overload protection easy to ensure.

[0019] In order to meet specific customer requirements, it is advantageous if the torque transmission plate is made of stainless steel or at least contains stainless steel.

[0020] It is advantageous if the friction linings are each connected to a flange in a rotationally fixed manner or to the torque transmission plate. This simplifies torque transmission via, for example, gear teeth. Furthermore, it has proven effective if the flange is designed as a single piece or consists of (at least / exactly) two non-rotatably connected partial flanges. If the damper is designed as a single-flange damper, a double-flange damper, or a triple-flange damper, a wider range of designs can be accommodated.

[0021] It is also design-efficient if the torque limiter flange merges into a drawn sheet metal hub.

[0022] The installation space is also used particularly efficiently if the torque limiter is arranged radially inside the damper.

[0023] In addition, it is desirable if a counter-disk of the damper is connected to the flywheel in a rotationally fixed manner, for example by riveting, with or without the interposition of a spacer element / spacer bolt.

[0024] The invention ultimately also relates to a vehicle drive train with an internal combustion engine, a transmission and a kit according to the invention arranged therebetween.

[0025] In other words, the kit of the invention is characterized in that the damper uses the flywheel as a drive plate, meaning that the damper is partially pushed axially into the flywheel. The flywheel has spring windows in which the compression springs are located, and through which they are actuated on one side. The result is a nested structure of the flywheel relative to the damper. The use of a sheet metal flywheel, which is manufactured as far away from tools as possible and has a higher density than a cast iron flywheel, has proven successful in practice. It is advantageous if the inertial mass is positioned predominantly as far out as possible. Screwing the damper to the flywheel is unnecessary. A screwless solution, for example using a rivet or weld, is conceivable.

[0026] The sheet metal flywheel is folded on the outside to maximize the usable moment of inertia. It has spring apertures for the damper's compression springs. The compression springs are preferably provided with plastic cups at their ends to reduce wear.

[0027] The upper edge of the spring apertures in the flywheel are embossed at an angle to ensure proper engagement of the compression springs or cups. This design eliminates the need for separate damper drive plates. While a single-flange damper is generally described, two- or three-flange dampers are also conceivable. It would also be possible to create space in the flywheel by creating apertures for the compression springs of these special two- or three-flange dampers.

[0028] In principle, it is desirable for a damper counter plate to be riveted to the flywheel. However, if the installation space allows it in certain applications, it is also conceivable to use it directly, without spacers.

[0029] A second friction device with a friction control disc could also be integrated into the damper.

[0030] In special designs, the damper output would be the hub flange, which transmits the torque to a radially inner torque limiter (ITL). The flange could serve directly as a friction partner between the pads. The basic plan is to rivet a smaller and thinner stainless steel disc onto the flange, which would frictionally engage the torque limiter. Such stainless steel discs offer particular advantages in corrosion tests.

[0031] A (radially) internal torque limiter has the advantage that the moment of inertia on the gearbox input shaft is reduced, resulting in lower torques there and thus better protection of the part.

[0032] It's also worth mentioning that the output element in the invention is a hub drawn from sheet metal, the teeth of which engage with a counterpart of the transmission input shaft. A sheet metal part is preferably riveted to this hub, so that these two parts hold the torque limiter together.

[0033] Flywheel bolts, i.e., bolts that secure the flywheel to the crankshaft or a crank-mounted part, can be tightened through any holes in the latter hub. Since the hub holes usually no longer line up with the bolts after the torque limiter has slipped, a clamping device can be added here, allowing the hub to be easily unlocked and rotated or removed, making the bolts accessible for disassembly.

[0034] In principle, it is also conceivable that the damper output (hub of the flange) is also slightly twisted against the compression springs in order to access the screws for assembly / disassembly.

[0035] At the core of the invention is a special design with a flywheel with an integrated torsional vibration damper and (downstream) torque limiter. The torsional vibration damper uses the flywheel as a drive plate, meaning the torsional vibration damper is partially pushed axially into the flywheel. The flywheel has spring apertures in which the compression springs of the torsional vibration damper are located, and through which they are actuated on one side. This results in a nested structure of the flywheel and the torsional vibration damper.

[0036] Such inventive kits, consisting of a flywheel and a damper, can be used in all internal combustion engines. However, hybrid systems are particularly well-suited for this application.

[0037] The invention is explained in more detail below with the aid of a drawing. It shows:

[0038] Fig. 1 shows a first embodiment in a cross section along the longitudinal axis of the drive train or along the axis of rotation around which the flywheel rotates, Fig. 2 shows a longitudinally sectioned illustration of a further embodiment, similar to that of Fig. 1, but in a perspective illustration.

[0039] The figures are merely schematic and serve only to facilitate understanding of the invention. The same elements are provided with the same reference numerals. Features of the individual embodiments are interchangeable or may complement each other.

[0040] Fig. 1 shows a kit 1 according to the invention. The kit has a one-piece flywheel 2 and a damper / torsional vibration damper 3.

[0041] Essentially, torque flows from an internal combustion engine (not shown) via the flywheel 2 into the damper 3 and a downstream torque limiter 4 to a transmission (not shown). In principle, torque flow in the opposite direction is also possible. In particular, the flywheel 2 is designed as a single component and can be or is screwed directly, i.e., without any additional intervening components, to a crankshaft of the internal combustion engine.

[0042] The flywheel 2 has a plurality of windows 5 distributed over the circumference. A spring 6 of the damper 3 engages in each of these windows 5. In the present embodiment, each window 5 is designed as a through hole, but can also be designed as a blind hole.

[0043] As can also be seen in Fig. 2, the ends of the springs 6 are covered with end caps 7. These end caps 7 are supported on the one hand on the flywheel 2 and a counter disc 8 and on the other hand on a hub flange 9.

[0044] The hub flange 9 is, as can be seen in Fig. 1, connected to a torque transmission plate 11 of the torque limiter 4 via a rivet 10. The spring 6 is a compression spring, namely a helical compression spring formed by a wire 12 having a thickness / wire thickness 13. At least one-third of the wire thickness 13 of the wire 12 of the spring 6 extends into the window 5 of the flywheel 2, preferably half, more preferably at least two-thirds. In the present case, the spring 6 engages by approximately twice the wire thickness 13, such that the spring 6 extends into the window 5 on a first end face of the flywheel 2, but does not protrude beyond a second end face 15 of the flywheel 2, preferably ending exactly there.

[0045] The window 5 has a slanted embossing 16. This ensures the compression springs, or rather the cup-like end caps 7, are properly seated on the flywheel. The upper edge of the (spring) window 5 is thus machined during the tooling process to provide the slanted embossing 16.

[0046] The flywheel 2 is made of sheet metal. In principle, a cast construction is conceivable, but not preferred. The good machinability of sheet metal, even at high cycle rates, supports the preference for this material. It also makes it particularly easy to provide a doubling 17 in a radially outer region, preferably at the radially outer end of the flywheel 2. The sheet metal flywheel 2 is thus folded radially outward there.

[0047] The torque limiter 4 has two friction linings 18, between which the stainless steel torque transmission plate 11 is clamped due to the action of a disc spring 19. A support disc 20 can be inserted. The support disc 20 can be attached to a plate / disk 21 to transmit the torque. This plate / disk 21 is then in turn fastened to a flange 23 via a rivet 22. The flange 23 has a hub 24, which is designed to transmit the torque to a subsequent component, such as a transmission input shaft. A spacer element 25, such as a spacer bolt, engages the flywheel 2. The hub flange 9 and the counter disc 8 engage it. The counter disc 8 also has a vane 26. The use of an additional disc spring 27, a friction ring 28, and a friction sleeve 29 enables the use of a friction device. The disc spring 27, the friction ring 28 and the friction sleeve 29 thus represent the friction device.

[0048] By using a cover plate 30 and a crankshaft screw 31, a torque-resistant connection to the crankshaft can be ensured.

[0049] Fig. 2 shows a slightly modified embodiment.

[0050] In both figures, the longitudinal axes / rotational axes of kit 1 are marked with reference numeral 32. This axis 32 defines the axial direction. The radial direction is marked with reference numeral 33.

[0051] List of reference symbols

[0052] kit

[0053] flywheel

[0054] Damper / torsional vibration damper

[0055] Torque limiter / torque limiter (ITL)

[0056] Window

[0057] Feather

[0058] End cap

[0059] Counter pane

[0060] Hub flange

[0061] rivet

[0062] Torque transmission plate

[0063] wire

[0064] Wire thickness first end face second end face oblique stamping

[0065] Doubling

[0066] Friction lining / lining

[0067] Disc spring (ITL)

[0068] Support disc

[0069] Sheet metal / disc

[0070] rivet

[0071] flange

[0072] hub

[0073] spacer element

[0074] wing

[0075] Disc spring (friction device)

[0076] friction ring

[0077] Friction sleeve

[0078] Cover plate

[0079] (Crankshaft) screw 32 rotation axis / longitudinal axis / axial direction

[0080] 33 Radial direction

Claims

Patent claims 1. Kit (1) comprising a one-piece flywheel (2) which can be screwed directly to a crankshaft of an internal combustion engine and a damper (3) for transmitting torque from the internal combustion engine to a downstream transmission of a vehicle drive train, characterized in that windows (5) are present in the flywheel (2), in each of which at least one spring (6) of the damper (3) at least partially engages.

2. Kit (1) according to claim 1, characterized in that the spring (6) only engages in the window (5) or through the window (5).

3. Kit (1) according to claim 1 or 2, characterized in that the spring (6) designed as a compression spring is supported on the flywheel (2) directly or with the interposition of stop elements.

4. Kit (1) according to claim 3, characterized in that the compression spring is designed as a straight spring (6) with or without end caps.

5. Kit (1) according to claim 4, characterized in that the end cap (7) is designed as a cup, sleeve or pot made of plastic or metal.

6. Kit (1) according to one of claims 1 to 5, characterized in that the spring (6) engages in the window (5) by at least one third of the thickness (13) of the wire (12) from which the spring (6) is formed.

7. Kit (1) according to one of claims 1 to 6, characterized in that a torque limiter (4) is connected downstream of the damper (3) in the torque curve from the internal combustion engine to the transmission.

8. Kit (1) according to one of claims 1 to 7, characterized in that a wing (26) protrudes from a counter-disk (8).

9. Kit (1) according to claim 8, characterized in that the wing (26) is present at the radially outer end / at the level of the windows (5) and / or is embossed at an angle.

10. Vehicle drive train with an internal combustion engine, a transmission and a kit (1) arranged therebetween according to one of the preceding claims.

Images