Robust damper for crankshafts with pendulum

Abstract

Crankshaft assembly with pendulum (32) for an internal combustion engine comprising the following: a crankshaft (37); a pendulum (32); a pendulum support attached to the crankshaft (37), wherein the pendulum (32) is attached to the pendulum support; a clip body (52) attached to the pendulum support and to the crankshaft (37), wherein the clip body (52) has a buffer retaining arm (58) and a pendulum support mounting arm (56), wherein the buffer retaining arm (58) of the clip body (52) has a channel formed therein, through which the pendulum support passes, thereby dividing a damper surface containing the channel into two surfaces; and a rubber or elastomer damper (54) attached to the buffer support arm (58).

Description

TECHNICAL AREA

[0001] The disclosed concept according to the invention relates generally to crankshafts with pendulums made of stamped steel for internal combustion engines. In particular, the disclosed concept according to the invention relates to a robust damper arrangement for use with crankshaft pendulums made of stamped steel, which prevents a metal-on-metal impact of the pendulum arrangement on the pendulum support by providing robust dampers that include a buffer molded from nylon or another durable material and are attached to a clip. The clip is fixed to the pendulum made of stamped steel. BACKGROUND OF THE INVENTION

[0002] Internal combustion engines with a relatively small number of cylinders are an attractive solution for automakers seeking improved fuel economy. To compensate for the reduction in displacement, manufacturers have developed technologies to enhance engine performance, such as direct fuel injection, turbocharging, and variable intake and exhaust camshaft timing. This allows six- and eight-cylinder engines to be downsized without sacrificing power output.

[0003] An undesirable consequence of engines with a small number of cylinders is strong torsional vibration of the crankshaft and strong vibration of the engine block, caused by various forces, such as first- and second-order engine forces, which are not canceled out. Such torsional vibrations are ultimately transmitted through the engine bearings and to the vehicle structure.

[0004] Engineers have addressed these vibrations with varying degrees of success through different approaches, often resulting in increased manufacturing costs and reduced fuel economy. One proposed solution for managing excessive vibrations is the incorporation of one or more pendulums on the crankshaft to reduce crankshaft torsional vibrations and the resulting noise and roughness of the vehicle. Such pendulums attached to the crankshaft act as vibration dampers, as they are designed to address and thus reduce vibrations generated by oscillating torque, leading to a smoother torque delivery from the crankshaft. This approach is also used by designers of some aircraft reciprocating engines, where the pendulums ensure a smooth output torque and reduce stress within the crankshaft itself.

[0005] US Patent 8,813,604 B2 discloses a device for damping vibrations in an internal combustion engine. The device comprises a crankshaft with a cam. The cam has a flange with an opening connected to the cam body. A pendulum is pivotally connected to the flange so that the pendulum can follow an epicycloidal path.

[0006] An example of a vibration damper pendulum connected to a power engine crankshaft is set forth in the US patent (published as US 4,739,679 A) which has been transferred to the acquirer of the present application. According to the arrangement set forth in that patent, a pendulum comprises an inner curved cam tappet surface which is alternately engaged and disengaged from a pin-like cam fixed to the pendulum support.

[0007] The crankshaft pendulum is connected to the pendulum support by means of pairs of rollers that move along matching curved tracks. Although there are several variations of the movable connection between the pendulum and the crankshaft, it is common to use roller journals as contact points between these two components.

[0008] Each roller journal requires a pendulum roller journal raceway in which the rolling elements can roll. Common roller journal raceways have large distances between the raceway walls and the roller journals. When the engine is running and the crankshaft is rotating, centrifugal force holds the pendulum in its fully extended position. The pendulum responds to the oscillating torque by moving from side to side. This reduces the transmission of oscillating torque to the transmission and improves noise, vibration, and harshness (NVH) characteristics. If the oscillating torque is too high, the pendulum can strike the dampers. In this case, the pendulums would need to be throttled. The other time the pendulums strike the dampers is during start-up and shutdown, when the centrifugal force is insufficient to overcome gravity.In these three cases, the dampers are designed to reduce metal-on-metal NVH (noise, vibration, and harshness). In this position, centrifugal force is sufficient to overcome gravity, and torsional forces are so low that they do not cause any back-and-forth motion of the pendulum. However, when the engine is shut down and the crankshaft's rotation ceases, so does the centrifugal force. No longer held in its fully extended position, the pendulum can move through its entire travel, experiencing a gravity-induced fall if, at the point of stopping, the pendulum's position is "up" or, more generally, above the crankshaft's centerline. If the pendulum is stopped in this position, it will fall before metal-on-metal contact occurs, thus reducing unwanted NVH in the engine and, consequently, in the vehicle.

[0009] To compensate for this, rubber dampers are arranged on the pendulum or pendulum support to cushion the metal-to-metal contact. During excessive pendulum excitation or during engine starts or stops, the dampers reach their stops. In known designs, the dampers are inserted into blind pockets molded either in the pendulum or the pendulum support. Due to insufficient grip length, these dampers tend to fall out of their pockets, thus not only failing to fulfill their intended purpose but also creating a risk of clogged oil lines and consequently causing premature engine failure.

[0010] Furthermore, damper technologies have not kept pace with the design development of the pendulum itself. More recent pendulum designs, such as that disclosed in USSN 14 / 663,322, which was transferred to the purchaser of the present application, and which is hereby incorporated in its entirety by reference, disclose a pendulum and pendulum support made of stamped steel for attachment to the crankshaft. The stamped steel design necessitates an alternative approach to pendulum dampers.

[0011] Therefore, a new approach to pendulum dampers is needed to address the problems associated with known arrangements. BRIEF DESCRIPTION OF THE INVENTION

[0012] The disclosed concept according to the invention overcomes the challenges faced by known pendulum arrangements for internal combustion engines by providing a robust damper clip that can be used with pendulum carriers made of stamped steel. Regardless of engine operation, the pendulum carrier damper clip of the disclosed concept according to the invention remains fixed to the pendulum carrier arrangement, thereby effectively reducing NVH (noise, vibration, and harshness).

[0013] The pendulum arrangement for mounting the crankshaft of an internal combustion engine of the disclosed concept according to the invention comprises a pendulum support damper clip attached to the pendulum support made of stamped steel. Using the stamped steel support provides more space to accommodate a more robust damper, as described herein and illustrated in the accompanying figures.

[0014] The pendulum carrier damper clip can have either two separate, L-shaped clips or a single, U-shaped clip. If the pendulum carrier damper clip includes two separate clips, each clip incorporates a damper surface to which the damper is attached and a mounting leg for securing the clip to the pendulum carrier and crankshaft using a fastener such as a bolt. The damper surface has a channel that the pendulum carrier passes through, effectively dividing the damper surface into two surfaces. A damper is attached to each surface.

[0015] If the pendulum support damper is a single, U-shaped part, a channel is formed along the longitudinal axis of the damper surface. The pendulum support passes through this channel. Dampers are provided on each of the surfaces.

[0016] The damper is an energy-absorbing, elastomeric material, which can be a natural or synthetic polymer, such as rubber or nylon. The damper is attached to the shock absorber strut by an adhesive that can withstand both the high operating temperatures of the internal combustion engine and engine oil.

[0017] The above advantages and further advantages and features will become apparent from the following detailed description of the preferred embodiments in combination with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] For a more comprehensive understanding of the present invention, reference is now made to the embodiments which are shown in more detail in the accompanying drawings and are described below with reference to examples of the invention, wherein: Fig. 1 is an expanded view of the components of a pendulum arrangement made of stamped steel; Fig. 2 a perspective view of a stamped pendulum support and a method for attaching it to the crankshaft; Fig. 3 an end view of the support of Fig. 2 is; Fig. 4 is a side view of a pendulum support damper clip according to a first embodiment of the disclosed concept according to the invention; Fig. 5 an end view of the pendulum support damper clip from Fig. 4 is; Fig. 6 a top view of the pendulum support damper clip of Fig. 4 is; Fig. 7 a perspective view of the pendulum support damper clip from Fig. 4 is; Fig. Figure 8 shows a perspective view of the pendulum and the pendulum support, on which the pendulum support damper clip is attached. Fig. 4 is attached; Fig. 9 a perspective view of the pendulum and pendulum support, to which a pendulum support damper clip is attached according to the second embodiment of the disclosed concept according to the invention; and Fig. 10. A split view of the pendulum, pendulum support and pendulum support damper clips. Fig. 9 is; DETAILED DESCRIPTION OF THE PREFERRED EXECUTION FORM

[0019] The same reference symbols are used in the following figures to refer to the same components. The following description details various operating parameters and components for different designed embodiments. These specific parameters and components are listed as examples and should not be considered limitations.

[0020] Referring to Fig. 1, Fig. 2 to Fig. Figure 3 shows views of a pendulum arrangement made of stamped steel. Referring to Fig. 4, Fig. 5, Fig. 6, Fig. 7 to Fig. Figure 8 shows a first embodiment of a pendulum support damper clip for use with a pendulum made of stamped steel in various views. Referring to Fig. 9 and Fig. Figure 10 shows a second embodiment of a pendulum support damper clip for use with a pendulum made of stamped steel in various views.

[0021] The pendulums, pendulum supports, and pendulum support-pendulum support damper clips, as shown and described, offer improvements in cost and performance compared to the prior art. It is understood that the pendulums, pendulum supports, and pendulum support-pendulum support damper clips shown are only examples and not to be considered limiting.

[0022] Fig. Figure 1 is an exploded view of the components of a pendulum assembly made of stamped steel, generally represented as Figure 10. The pendulum assembly 10 comprises a flat-stamped pendulum half 12, a flat-stamped pendulum half 14, and a flat-stamped intermediate spacer 16. A pair of mounting holes 18 and 18' for screws or rivets are formed in the flat-stamped pendulum half 12. The mounting holes 18 and 18' can be omitted, and instead, the flat-stamped halves can be fastened by welding. A pair of kidney-shaped roller tracks (having a circular or cycloidal shape) 20 and 20' are formed by machining in the flat-stamped pendulum half 12. A pair of mounting holes 22 and 22' for screws or rivets are formed in the second flat-stamped pendulum half 14. The mounting holes 22 and 22' can be omitted, and instead, the flat-stamped halves can be fastened by welding.A pair of kidney-shaped roller tracks 24 and 24' are formed by machining in the flat-stamped pendulum half 14. A pair of mounting holes 25 and 25' for screws or rivets are formed in the flat-stamped intermediate spacer 16. The shapes and features are provided by stamping the flat-stamped pendulum half 12, the flat-stamped pendulum half 14, and the flat-stamped intermediate spacer 16.

[0023] Mechanical fasteners such as rivets are used to fasten the flat-stamped pendulum half 12, the flat-stamped pendulum half 14, and the flat-stamped intermediate spacer 16 together. Alternatively, other mechanical fasteners or welding can be used.

[0024] In addition to the fact that the pendulum arrangement 10 is formed from stamped components, the disclosed concept according to the invention provides that the pendulum support used to attach the pendulum arrangement 10 to the crankshaft is also preferably formed from stamped components.

[0025] Fig. Figure 2 shows a perspective view of a pendulum arrangement, generally represented as 30, which includes a pendulum 32 and a pendulum support arrangement 34. The pendulum 32 can be of a prior art type or of the cold-forged or cold-formed steel type, as disclosed here.

[0026] The support assembly 34 includes a mounting hole 36 for receiving a fastening element such as a collar bolt (not shown) for a crankshaft 37. The support assembly 34 further includes a first U-shaped stamped support shoulder plate 38, a second U-shaped stamped support shoulder plate 38', and a central stamped support plate 40 fitted between the first stamped support shoulder plate 38 and the second stamped support shoulder plate 38'. The U-shaped stamped support shoulder plates 38 and 38' and the central stamped support plate 40 can be fastened to one another in various ways, including, but not limited to, mechanical fastening, welding, pressing, and pinning.

[0027] Referring to Fig. 4, Fig. 5, Fig. 6, Fig. 7 to Fig. Figure 8 shows a first embodiment of a pendulum support-pendulum support damper clip according to the disclosed concept of the invention in various views. A pendulum support-pendulum support damper clip, generally shown as 50, includes a clip body 52 to which dampers 54 and 54' are attached. The clip body 52 includes a pendulum support mounting arm 56 and a buffer retaining arm 58. A fastening element through-hole 60 is formed in the pendulum support mounting arm 56.

[0028] The clip body 52 can be cast or, preferably, stamped. The clip body 52 can be made of one of several materials, including, but not limited to, mold or stamped steel. The dampers 54 and 54' can be composed of any robust and elastic elastomeric materials, including natural or synthetic polymers such as nylon. The dampers 54 and 54' are attached to the upper, pendulum-facing surface of the buffer retaining arm 58 by any one of several known adhesives that are both heat and oil resistant.

[0029] The pendulum support damper clip 50 is supplied in pairs for attachment to the pendulum support. This arrangement is in Fig. Figure 8 shows a perspective view of the pendulum assembly 30 with two pendulum support damper clips 50 attached to it. As shown, one of the pendulum support damper clips 50 is fastened to the support assembly 34 and to the camshaft 37 by a fastening element such as a screw 62. It is understood that both pendulum support damper clips 50 are fastened in the same way, although in Fig. 8 only one screw 62 is visible. It is also understood that the pendulum carrier-pendulum carrier damper clips 50 are attached to the camshaft 37 at the same time as the carrier assembly 34 is attached to it during the assembly of the camshaft.

[0030] Referring to Fig. 9 to Fig. Figure 10 shows a second embodiment of a pendulum support-pendulum support damper clip according to the disclosed concept of the invention in the two views. In this embodiment, a pendulum support arrangement, generally represented as 70, includes a stamped crankshaft mounting bracket 72 and a stamped pendulum support mounting bracket 74. The crankshaft mounting bracket 72 includes a pendulum support mounting bracket channel 76 and a pair of mounting holes 78 and 78' for receiving a fastening element such as a collar bolt (not shown) for fastening the crankshaft mounting bracket 72 to the crankshaft (not shown).

[0031] The stamped pendulum support bracket 74 and the crankshaft support bracket 72 can be joined to one another in a variety of ways, including, but not limited to, mechanical fastening, welding, pressing, and pinning. Kidney-shaped roller tracks 80 and 80' are formed by the stamped pendulum support bracket 74. The pendulum (not shown) attached to the pendulum support assembly 70 can be of a prior art type or of the cold-forged or cold-formed steel type disclosed herein.

[0032] A pendulum beam-pendulum beam damper clip, generally represented as 90, includes a clip body 92 to which dampers 94 and 94' are attached. The clip body 92 includes a first pendulum beam mounting arm 96, a second pendulum beam mounting arm 96', and a buffer retaining arm 98. A first fastening element through-hole 100 is formed in the first pendulum beam mounting arm 96, and a second fastening element through-hole 100' is formed in the second pendulum beam mounting arm 96'.

[0033] Like the clip body 52 described above, the clip body 92 can be cast or, preferably, stamped. The clip body 92 can also be made of one of several materials, including, but not limited to, mold or stamped steel. The dampers 94 and 94' can also be made of rubber or any robust and elastic elastomeric materials, including synthetic polymers such as nylon. The dampers 94 and 94' are attached to the upper, pendulum-facing surface of the buffer retaining arm 98 by any one of several known adhesives that are both heat- and oil-resistant.

[0034] A pendulum carrier-pendulum carrier damper clip 90 is essentially fitted over the crankshaft mounting bracket 72, as shown in Fig.9 shown. As shown, the pendulum carrier-pendulum carrier damper clip 90 is attached to the crankshaft mounting bracket 72 and to the camshaft (not shown) by a fastening element such as screws 102 and 102'.

[0035] The disclosed concept according to the invention, as set out above, overcomes the challenges posed by known pendulum crankshaft arrangements for internal combustion engines by providing an improved impact-damping arrangement that offers a robust impact-absorbing surface which reduces undesirable NVH during engine start-up and shutdown. However, it will be readily apparent to those skilled in the art from this discussion and the accompanying drawings and claims that various changes, modifications, and variations can be made without departing from the true spirit and legitimate scope of the invention as set forth in the following claims.

Claims

[1] Crankshaft arrangement with pendulum (32) for an internal combustion engine comprising: a crankshaft (37); a pendulum (32); a pendulum support attached to the crankshaft (37), wherein the pendulum (32) is attached to the pendulum support; a clip body (52) attached to the pendulum support and to the crankshaft (37), wherein the clip body (52) has a buffer retaining arm (58) and a pendulum support mounting arm (56), wherein the buffer retaining arm (58) of the clip body (52) has a channel formed therein, through which the pendulum support passes, thereby dividing a damper surface containing the channel into two surfaces; and a rubber or elastomer damper (54) attached to the buffer support arm (58). [2] Crankshaft assembly with pendulum (32) according to claim 1, wherein the clip body (52) is L-shaped. [3] Crankshaft assembly with pendulum (32) according to claim 1, wherein the clip body (52) includes two opposing L-shaped ends. [4] Crankshaft assembly with pendulum (32) according to claim 1, wherein the clip body (52) comprises two opposing L-shaped clips. [5] Crankshaft assembly with pendulum (32) according to claim 1, wherein the buffer retaining arm (58) has a longitudinal axis and wherein the channel is formed along the longitudinal axis. [6] Crankshaft assembly with pendulum (32) according to claim 1, which further includes a pair of screws (62) for attaching the pendulum carrier and the clip body (52) to the crankshaft (37). [7] Crankshaft arrangement with pendulum (32) for an internal combustion engine comprising: a crankshaft (37); a pendulum (32); a pendulum support attached to the crankshaft (37), wherein the pendulum (32) is attached to the pendulum support, the pendulum support comprising a stamped crankshaft mounting bracket (72) and a stamped pendulum support mounting bracket (74); a clip body (52) attached to the pendulum carrier and to the crankshaft (37), wherein the clip body (52) has an energy-absorbing damper (54), a buffer retaining arm (58) and a pendulum carrier mounting arm (56), wherein the energy-absorbing damper (54) is attached to the buffer retaining arm (58) and wherein the buffer retaining arm (58) of the clip body (52) has a channel formed therein, through which the pendulum carrier passes, thereby dividing a damper surface containing the channel into two surfaces. [8] Crankshaft arrangement with pendulum (32) according to claim 7, wherein the energy-absorbing damper (54) consists of rubber or elastomeric material. [9] Crankshaft assembly with pendulum (32) according to claim 7, wherein the clip body (52) is L-shaped. [10] Crankshaft assembly with pendulum (32) according to claim 7, wherein the clip body (52) includes two opposing L-shaped ends. [11] Crankshaft assembly with pendulum (32) according to claim 7, wherein the clip body (52) comprises two opposing L-shaped clips. [12] Crankshaft arrangement with pendulum (32) for an internal combustion engine comprising: a crankshaft (37); a pendulum (32); a pendulum support attached to the crankshaft (37), wherein the pendulum (32) is attached to the pendulum support; a clip body (52) attached to the pendulum support and to the crankshaft (37), wherein the clip body (52) has a buffer retaining arm (58), the buffer retaining arm (58) having a channel formed therein to define two damper surfaces; and an energy-absorbing damper (54') attached to each of the damper surfaces. [13] Crankshaft assembly with pendulum (32) according to claim 12, wherein the clip body (52) is L-shaped.

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