Patent Application
20150316125
The present disclosure relates to a centrifugal pendulum including a rotation element and a pendulum flange, which is connected to the rotation element by means of a fastening means to transmit torque between the rotation element and the pendulum flange.
German Patent Application No. 10 2011 013 232 A1 discloses a centrifugal pendulum including a pendulum flange and pendulum masses arranged on both sides of the pendulum flange. The pendulum masses are connected to one another by means of a spacer bolt received in an arcuate section of the pendulum flange. Furthermore, the hub is supported for rotation about an axis of rotation and the pendulum flange is connected to the hub by means of a cold-rivet connection so as to be fixed against rotation relative to the hub. In shifting operations, excess torque may be introduced into the pendulum flange via the rivet connection, causing the pendulum masses to hit stops and creating noise that reduces the acoustic comfort. Moreover, the impact may shorten the useful life of the centrifugal pendulum.
An object of the present disclosure is to provide a low-noise centrifugal pendulum.
In accordance with the present disclosure, a low-noise centrifugal pendulum includes a rotation element and a pendulum flange, where the pendulum flange is connected to the rotation element by means of a fastening means to transmit torque between the rotation element and the pendulum flange, where the fastening means is designed in such a way that the transmission of torque between the pendulum flange and the rotation element is at least partly achieved by a non-positive or force-locking connection. By a “non-positive or force-locking connection” we mean that for torque greater than a certain amount, some slip, or relative rotation, occurs between the pendulum flange and the rotation element. In an example embodiment, the pendulum flange surrounds the rotation element.
An advantage of this design is that when torque peaks occur during a shifting operation, for instance, the pendulum flange may rotate relative to the hub to prevent the peak torque from being transmitted to the pendulum masses. This is a simple way of reducing the impulse introduced into the pendulum masses, effectively preventing any impact. Preventing the impact of the pendulum masses eliminates the noise of the impact. As a result, a low-noise centrifugal pendulum is provided.
In accordance with an example embodiment, the fastening means includes a tensioning means, a first fastening section disposed on the rotation element, a second fastening section disposed on the rotation element to be spaced apart from the first fastening section along an axis of rotation of the rotation element, where the first fastening section is assigned to a first end face of the pendulum flange, where the tensioning means is disposed between the second fastening section and a second end face of the pendulum flange, the second end face disposed opposite the first end face, and where the tensioning means is designed to press the pendulum flange in the direction of the first fastening section. In this way, torque may easily be transmitted between the hub and the pendulum flange via the first fastening section and the pendulum flange. Furthermore the pendulum flange may slip on the hub during peak torques, effectively limiting the impulse introduced into the pendulum masses.
In accordance with an example embodiment, the first fastening section and/or the second fastening section have a circumferential groove or the first fastening section has a protrusion and the second fastening section has a circumferential groove. In this way, the fastening sections may easily and inexpensively be formed on the hub, for instance in a machining process, in particular a turning process.
In accordance with an advantageous aspect, the protrusion may include a first contact surface facing the first end face of the pendulum flange and the tensioning means may press the pendulum flange against the first contact surface.
In accordance with an advantageous aspect, a first securing ring circumferentially surrounding the rotation element and engaging in the first fastening section may be provided, the first securing ring having a first contact surface facing the first end face of the pendulum flange, where the tensioning means press the pendulum flange against the first contact surface. In this way, a transmission of torque between the hub, the first securing ring, and the pendulum flange may be reliably ensured.
In accordance with an example embodiment, the tensioning means includes at least a second securing ring engaging in the second fastening section and designed to introduce a tensioning force of the tensioning means into the rotation element, the tensioning force being effective in a direction parallel to the axis of rotation. In this way, the pendulum flange may especially inexpensively and quickly be connected to the hub during the manufacturing of the centrifugal pendulum.
In accordance with an example embodiment, the second securing ring has an endface side second contact surface facing the second end face of the pendulum flange, where on the end face facing away from the pendulum flange, the second securing ring has a first incline and is designed to provide a radial pre-loading force to press the first incline against the second fastening section in such a way that the securing ring provides the tensioning force that extends in a direction parallel to the axis of rotation and introduces the tensioning force into the second end face of the pendulum flange via the second contact surface. In this embodiment, the tensioning means for fastening the pendulum flange to the rotation element is particularly slim in an axial direction and has a particularly low total weight.
In accordance with an example embodiment, the tensioning means includes at least one spring element disposed between the first fastening section and the second securing ring and, for example, embodied as a diaphragm spring or a ring spring or a coil spring, where the spring element, for example, at least partly surrounds the rotation element in a circumferential direction. In this way, a particularly high tensioning force may be provided, allowing a particularly high torque to be transmitted between the pendulum flange and the hub.
In accordance with an example embodiment, the protrusion includes a third incline and the pendulum flange has a fourth incline designed to correspond to the third incline, the fourth incline being pressed against the third incline by the tensioning means. In this way, the pendulum flange may be centered on the hub, providing easy alignment of the pendulum flange relative to the hub during manufacturing and thus avoiding imbalances.
A high torque may be transmitted between the pendulum flange and the rotation element when a pawl device is provided at least partly to transmit torque between the pendulum flange and the rotation element, where the pawl device includes at least a receiving element and an engagement element engaging in the receiving element and where the pawl device, for example, is fixed to the pendulum flange by the fastening means.
The invention will be explained in more detail below based on the drawings, in which identical components are designated by identical reference symbols.
The nature and mode of operation of the present invention will now be more fully described in the following detailed description of the invention taken with the accompanying drawing figures, in which:
Fastening means 50 includes fastening section 55 arranged to the left of pendulum flange 25 on shaft 20. Fastening means 50 includes fastening section 60 disposed essentially to the right of pendulum flange 25 on shaft 20. Intermediate section 61, whose length essentially corresponds to the axial extension of pendulum flange 25, and which is completely surrounded by the latter in a circumferential direction, is provided between fastening sections 55, 60. Tensioning means 65, designed to provide tensioning force FS parallel to axis of rotation 15, is provided in fastening section 60.
Fastening section 55 includes protrusion 70 whose diameter is greater than the diameter of shaft 20 in intermediate section 61. Protrusion 70 includes contact surface 75 facing left-hand side end face 80 of pendulum flange 25.
Fastening section 60 is embodied as groove 85 with rectangular trapezoidal shape in shaft 20, with the rectangle of the trapezoidal shape formed on side surface 86 of groove 85, the side surface 86 facing pendulum flange 25. Tensioning means 65 comprises securing ring 90 engaging in groove 85. Securing ring 90 includes contact surface 95 facing pendulum flange 25 and resting against end face 100 of pendulum flange 25, end face 100 disposed on the right-hand side.
Intermediate section 61 has an axial extension d between contact surface 75 of protrusion 70 and side surface 86 of groove 85. Axial extension d is smaller than axial extension b of pendulum flange 25, so that circumferentially, groove 85 is partly covered by pendulum flange 25.
On and end face facing away from end face 100, securing ring 90 has incline 105. Incline 105 is oriented at an angle relative to axis of rotation 15 of centrifugal pendulum 10 and at an angle relative to end face 100 of pendulum flange 25. Contact surface 75, end faces 80, 100, and contact surface 90 are aligned at right angles relative to axis of rotation 15, or, in other words, axis of rotation 15 forms a normal vector of contact surface 75 of protrusion 70, for both end faces 80, 100 of pendulum flange 25, and for contact surface 95 of securing ring 90. Groove 85 further comprises incline 110 on side surface 111 disposed opposite side surface 86. Incline 110 is oriented to correspond to inclination 105 of securing ring 90, so that in an assembled state of securing ring 90, essentially the entire area of inclines 105, 110 are located in groove 85. Due to inclines 105, 110, groove 85 and securing ring 90, respectively, are axially smaller on the inside than on the outside as viewed in a radial direction.
In a relaxed state, the diameter of securing ring 90 is advantageously smaller than interior diameter d2 of groove 85, which means that securing ring 90 is always tensioned in groove 85 to ensure that securing ring 90 is securely fitted in groove 85. Before securing ring 90 is mounted, pendulum flange 25 is slid onto shaft 20 until end face 80 rests against contact surface 75 of protrusion 70. Afterwards, securing ring 90 is mounted. To insert securing ring 90 into groove 85, securing ring 90 is widened by means of non-illustrated lugs and a non-illustrated tool and slid onto shaft 20 in a tensioned state axially on the right-hand side. When securing ring 90 is in the region of groove 85, the tool is removed from the lugs to allow securing ring 90 to relax, i.e. to contract and reduce its diameter in such a way that incline 105 comes to rest against incline 110. Furthermore, contact surface 95 is pressed against end face 100 of pendulum flange 25, axially displacing pendulum flange 25 in the direction of protrusion 70 up until end face 80 of pendulum flange 25 rests against contact surface 75 of protrusion 70. As pendulum flange 25 is being moved, securing ring 90 is received further in groove 85. Once contact surfaces 75, 95 rest against end faces 80, 100, radial force FR is partly transformed into tensioning force FS by inclines 105, 110. Securing ring 90 introduces tensioning force FS into pendulum flange 25 via contact surface 95 and end face 100. Furthermore, end face 80 of pendulum flange 25 is pressed against contact surface 75 of protrusion 70 and protrusion 70 provides a counterforce so that pendulum flange 25 is tensioned thereon due to tensioning force FS.
When a fluctuating torque is introduced into shaft 20 via interior toothing 20, for instance from a combustion engine, this torque is transmitted to pendulum flange 25 via contact surface 75 and end face 80, respectively, on protrusion 70 as well as via inclines 105, 110 that rest against each other, and via contact surface 95 and end face 100. Pendulum masses 30 act to reduce the fluctuating torque and dampen the vibration, respectively, in a known way.
Depending on the static friction coefficient between contact surfaces 75, 96 and end faces 80, 100 as well as between contact surfaces 105, 110, the maximum torque transmittable between shaft 20 and pendulum flange 25 is determined by tensioning force FS. If the maximum transmittable torque is exceeded for instance due to peak torques that may occur during shifting operations and during the start-up of a combustion engine, shaft 20 will temporarily slip relative to pendulum flange 25, transitioning to dynamic friction. As a result, the maximum torque transmittable based on the dynamic friction continues to be transmitted to pendulum flange 25 and the function of pendulum masses 30 is maintained. Torque peaks that exceed the maximum transmittable torque, however, are not transmitted to pendulum flange 30, avoiding any temporary excess acceleration of pendulum masses 30 and preventing pendulum masses 30 and spacer bolts 40, respectively, from hitting recess 35. As a result, noise caused by the impact of spacer bolt 40 on sections 35 of centrifugal pendulum 10 may be reliably avoided, resulting in a much more silent operation of centrifugal pendulum 10 compared to a conventional centrifugal pendulums.
A further advantage of the embodiment shown in
As explained with reference to
Securing ring 230 engages in groove 210. Securing ring 230 has a rectangular cross-section. Securing ring 235 engages in groove 215. The axial length bS of securing rings 230, 235 is smaller than width bN of groove 210, 215, which means that securing ring 230 is axially movable in groove 210. Securing ring 235 is designed like securing ring shown in
Securing ring 230 and securing ring 235 are designed to be preloaded for assembling purposes and to provide radial force FR. Radial force FR causes securing ring 230 to be reliably retained in groove 230.
Due to radial force FR, incline 240 of securing ring 235 rests on groove edge 245 on groove surface 265 of groove 215. As explained with reference to
Tensioning force FS causes pendulum flange 25 and securing ring 230 to be displaced axially to the left until contact surface 256 provided on securing ring 230 opposite contact surface 250 rests against groove surface 260. During the axial displacement, securing ring 235 continues to contract and engages farther into groove 215. When contact surface 260 rests against groove surface 256, contact surface 250 rests against end face 80 and end face 100 rests against contact surface 255, securing ring 235 locks pendulum flange 25 on securing ring 230 so that torque coming from shaft 20 may non-positively be transmitted to pendulum flange 25 via fastening means 205, securing rings 230, 235 and grooves 210, 215. This causes torque to be transmitted between shaft 20 into contact surface 256 via groove surface 260 of groove 210 and to be introduced from securing ring 230 into end face 80 into pendulum flange 25 via contact surface 245. The torque is furthermore transmitted to end face 100 of pendulum flange 25 via securing ring 235, groove edge 245 engaged with incline 240 and further via securing ring 235 and contact surface 255. The same path may be used in an opposite order to transmit torque back from pendulum flange 25 into shaft 20 to dampen vibration caused by torque fluctuations.
An advantage of the embodiment shown in
Shaft 20 as the rotation element is fixed to pendulum flange 25 by fastening means 305 in a non-positive way to allow the transmission of torque between shaft 20 and pendulum flange 25. Fastening means 305 is essentially identical with the fastening means shown in
Pendulum flange 25 is connected to shaft 20 so as to be fixed against relative rotation by means of fastening means 405. Fastening section 55 is identical with the embodiment of the fastening means shown in
Pendulum flange 25 is fixed to shaft 20 so as to be fixed against relative rotation in a non-positive way by fastening means 505. Fastening means 505 corresponds to the fastening means shown in
Pendulum flange 25 is connected to shaft 20 by fastening means 605. In fastening section 55, shaft 20 includes protrusion 610, which is radially wider than the protrusion shown in
Pendulum flange 25 is connected to shaft 20 in a non-positive way so as to be fixed against relative rotation by means of fastening means 705. Fastening section 55 is embodied to be identical with the fastening means shown in
Pawl element 720 is disc-shaped and includes pawl bulge 730 that engages in recess 715. In terms of their arrangement, design, and number, pawl bulges 730 advantageously correspond to recesses 715. It is to be understood that the number of pawl bulges 730 may be different from the number of recesses 715. Radially to the inside, pawl element 720 comprises an interior toothing 735 meshing with outer toothing 725 of shaft 20 to allow pawl element 720 to be disposed on shaft 20 so as to be movable on the shaft in an axial direction relative to the shaft and to provide a positive transmission of torque between shaft 20 and pawl element 720. In the illustrated embodiment, pawl element 720 is aligned relative to the pendulum flange in such a way that a respective pawl bulge 730 engages in a respective recess 715 on the pendulum flange. Torque introduced into pawl element 720 is transmitted via pawl bulge 730 into recess 715 in pendulum flange 25. Torque may likewise be transmitted from pendulum flange 25 in an opposite direction of the path described above. As a result, pendulum flange 25 is positively connected to shaft 20 as the rotation element. An advantage of the positive or form-fitting connection described above is that it is easy to release by an axial displacement of pawl element 720 relative to pendulum flange 25.
A pawl element back side 740 facing away from pendulum flange 25 is in contact with spring element 420, which presses pawl element 720 onto end face 100 of pendulum flange 25. Pawl element contact surface 745 facing end face 100 of pendulum flange 25 is in contact with end face 100. Due to the contacting pressure, an axial displacement of pawl element 720 relative to pendulum flange 25 is avoided, ensuring that pawl bulges 730 reliably engage in recesses 715. As described with reference to
If peak torques that are higher than the maximum torque transmittable via fastening means 705 are introduced into shaft 20, the peak torques are absorbed by a slipping or rotation of shaft 20 relative to pendulum flange 25 and are not introduced into centrifugal pendulum 700. To allow shaft 20 to slip relative to the pendulum flange, recess 715 is contoured in such a way that the torque transmitted via recess 715 and the pawl bulge results in release force FL that counteracts tensioning force FS, pushing pawl element 720 in the direction of securing ring 415. If release force FL is greater than tensioning force FS, pawl bulges 730 are pushed out of recesses 715 and pawl element 720 is displaced in the direction of securing ring 415. Shaft 20 rotates pawl element 720 relative to pendulum flange 25 until the torque introduced into shaft 20 is lower than the transmittable torque. As long as release force FL is greater than tensioning force FS, shaft 20 continues to be rotated relative to pendulum flange 25 even if further recess 715 is located opposite pawl bulge 730. In this case, pawl bulge 730 will engage in the further recess 715 but will also be immediately released from the latter in the way described above. If the torque in shaft 20 drops below the maximum transmittable torque, shaft 20 is rotated relative to pendulum flange 25 until pawl bulge 730 is located opposite recess 715 and pawl element 720 is again pressed against pendulum flange 25 and pawl bulge 730 is pressed into recess 715 due to tensioning force FS
An advantage of this embodiment over the embodiments shown in
It is to be understood that the embodiments shown in
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2012 223 955.3 | Dec 2012 | DE | national |
| 10 2013 214 808.9 | Jul 2013 | DE | national |
The present application is the U.S. national stage application pursuant to 35 U.S.C. §371 of International Application No. PCT/DE2013/200328, filed Nov. 29, 2013, which application claims priority of German Application No. 10 2012 223 955.3, filed Dec. 20, 2012 and German Application No. 10 2013 214 808.9, filed Jul. 30, 2013.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/DE2013/200328 | 11/29/2013 | WO | 00 |
