Device with a decoupled cylindrical sleeve

Abstract

Device comprising a cylindrical sleeve (3, 13) arranged at least indirectly on a housing (7) with at least three radially outwardly extending pins (5), characterized in that each pin (5) is arranged between two cylindrical roller elements (6a, 6b) received on a housing (7) in order to support the cylindrical sleeve (3, 13) tangentially on the housing (7), wherein the respective pin (5) is displaceable in a radial direction relative to the housing (7) and thereby rolls on the respective roller element (6a, 6b), wherein at least a proportion of the roller elements (6a, 6b) have unequal outer diameters.

Description

[0001] The invention relates to a device with a cylindrical sleeve that is supported at least indirectly on a housing. Furthermore, the invention relates to a device designed as a planetary gear and a device designed as an electric machine.

[0002] German patent DE 102011 076 521 A1 discloses a housing-side mounting arrangement for a ring gear of a planetary gear set with a bearing plate for supporting an output shaft of the planetary gear set for an electric drive. A connecting section for transmitting the ring gear torque is provided between the bearing plate and a ring gear carrier that receives the ring gear, wherein the connecting section is designed such that it has a lower radial stiffness with respect to the ring gear carrier.

[0003] Furthermore, DE 11 2008 004 241 T5 discloses a device comprising a force transmission component arranged at least indirectly on a fastening component. The force transmission component has first and second teeth spaced apart from each other and extending radially outwards. The fastening component surrounds the force transmission component and has first and second recesses, each receiving a first tooth and a second tooth, respectively. A greater distance is provided between an outer surface of the first tooth and an inner surface of the first recess than that between an outer surface of the second tooth and an inner surface of the second recess. An elastically deformable damping component is provided between the outer surface of the first tooth and the inner surface of the first recess. The damping component can be designed as an O-ring or a similar ring-shaped resin component.

[0004] The object of the present invention is to propose a device that achieves acoustic vibration decoupling in a structurally simple manner. This object is achieved by the subject matter of claim 1. Preferred embodiments are the subject of the dependent claims.

[0005] A device according to the invention comprises a cylindrical sleeve arranged at least indirectly on a housing, with at least three radially outwardly extending pins, each pin bearing between two cylindrical roller elements mounted on the housing to support the cylindrical sleeve tangentially against the housing. In other words, the cylindrical sleeve is axially supported, at least partially, in a stationary housing and is supported on the housing via the pins arranged on the respective roller elements, essentially tangentially. Thus, a torque acting on the cylindrical sleeve is transmitted tangentially into or from the housing via the pins and the roller elements, with each pin being displaceable in the radial direction relative to the housing and thereby able to roll along the respective roller element.

[0006] According to the invention, each pin is arranged between two roller elements mounted on the housing. That is, two roller elements are arranged in a recess on an inner surface of the housing and accommodate one of the pins, which is rigidly connected to the cylinder sleeve, between them. The roller elements are preferably designed as cylindrical bolts, rollers, or pins and extend substantially parallel to the longitudinal axis of the cylinder sleeve, thus enabling the pin to roll in a radial direction. The roller elements are therefore movably arranged in the radial direction of the pin such that the cylinder sleeve can displace radially relative to the housing. The pins are arranged substantially perpendicular to the longitudinal axis of the cylinder sleeve and extend radially outwards with respect to the longitudinal axis of the cylinder sleeve. There is no rigid connection between the pins and the associated roller elements.Rather, the pins are supported tangentially against the housing via their respective roller elements, depending on the torque applied to the cylinder sleeve. Therefore, there is not always contact between the pins and their respective roller elements. Instead, with a positive torque, the pin can contact one of the two roller elements held in the housing recess, and with an opposite torque, it can contact the other roller element held in the housing recess. In other words, torque is introduced into the housing tangentially, regardless of direction. Radial transmission of torque into the housing is thus prevented.

[0007] The roller elements allow the respective pins, which come into contact with them depending on the applied torque, to roll or slide along the roller element during radial movement of the cylinder sleeve. The pins are thus movably arranged radially between the two roller elements, allowing radial freedom of movement of the cylinder sleeve relative to the housing. In other words, the pins do not bear radially against the housing. The radial freedom of movement provided by the movable roller elements of the cylinder sleeve means that radial excitation or deformation of the cylinder sleeve can be almost completely absorbed by the system. By appropriately arranging the pins on the cylinder sleeve, it is ensured that the cylinder sleeve is always supported tangentially against the housing. Consequently, even radially acting forces on the cylinder sleeve are transferred tangentially into the housing.

[0008] Preferably, the pins are arranged evenly distributed around an outer circumferential surface of the cylinder sleeve to achieve a uniform force distribution and transmission from the cylinder sleeve to the housing. With four pins, they are thus located at the quarter points on the outer circumference of the cylinder sleeve; with three pins, at the third points. Alternatively, the pins could be arranged on an axial end face of the cylinder sleeve and extend radially outwards.

[0009] Preferably, there is line contact between the journals and the respective roller elements. Thus, the journals extend over at least a portion of the axial length of the cylinder sleeve. Preferably, the journals are as long as the axial length of the ring gear, so that each journal has a contact surface in each circumferential direction for contacting a respective roller element, in order to transmit a greater load compared to point contact.

[0010] The pins are preferably pressed into recesses in the cylinder sleeve. These recesses are formed on the outer circumference of the cylinder sleeve and are preferably designed as axial grooves. This simplifies the manufacture of the cylinder sleeve, as the pins are only subsequently bonded to the cylinder sleeve or pressed into the respective groove. Alternatively, the pins are metallurgically bonded to the cylinder sleeve. In other words, the pins can also be welded to the cylinder sleeve.

[0011] The invention includes the technical teaching that the pins and roller elements are arranged axially, at least indirectly, between a shoulder of the housing and a retaining ring. This provides additional axial support for the cylinder sleeve on the housing. The retaining ring can, for example, be designed as a snap ring and can furthermore be partially received in a circumferential groove on the inner circumference of the housing in order to transfer the axial forces from the cylinder sleeve into the housing or to support the cylinder sleeve axially on the housing. The shoulder is preferably integrally connected to or formed on the housing.

[0012] To increase the axial contact area, a thrust washer is arranged between the retaining ring and the pins. This clamps the roller elements and the cylinder sleeve axially within the housing between the shoulder of the housing and the thrust washer, which is axially secured by the retaining ring.

[0013] According to the invention, at least a proportion of the roller elements have unequal outer diameters. It is conceivable that the outer diameter of only one roller element differs from the other roller elements, that the outer diameter of several roller elements differs from the outer diameters of the other roller elements, or that the outer diameters of all roller elements differ from one another. This allows for the compensation of manufacturing tolerances, and the positioning of the cylinder sleeve in space can be adjusted by appropriately varying the roller diameter. In this way, a virtually backlash-free system is achieved.

[0014] According to one embodiment, the device is designed as a planetary gear system comprising a sun gear, a ring gear, and at least one planet gear set with several planet gears, which are rotatably mounted, at least indirectly, on a planet carrier. The journals extend radially outwards from the ring gear, with each journal arranged between two roller elements mounted on the housing to support the ring gear tangentially against the housing. In other words, the ring gear is to be understood as a cylindrical sleeve within the meaning of the invention, and the preceding descriptions of the device can readily be transferred to the planetary gear system.

[0015] Under load, the ring gear experiences vibration excitation due to the meshing forces between the ring gear and the planet gears meshing with it. In addition to these direct excitations, natural modes of the ring gear, also known as resonances, are excited, which, via the connection to the gearbox housing, could lead to acoustic disturbances in the overall system. To acoustically decouple the system, and thus improve its acoustic properties and reduce vibrations, radially oriented pins are arranged between the roller elements. These pins bear tangentially against the roller elements and are movable in the radial direction relative to the housing. Consequently, the vibration excitations are completely decoupled from the housing, while simultaneously providing a comparatively rigid support for the load-induced torque via the pins and roller elements on the housing.Thus, even without stationary fixing of the ring gear to the housing, unrestricted functionality of the device or the planetary gear can be guaranteed, while at the same time the acoustic excitation is completely shielded from the housing.

[0016] According to a further embodiment, the device is designed as an electric machine comprising a stator and a rotor rotatably driven relative to it, the journals extending radially outwards from the stator, each journal being arranged between two roller elements mounted on the housing to support the stator tangentially against the housing. In other words, the stator is to be understood as a cylindrical sleeve within the meaning of the invention, and the preceding descriptions of the device can readily be transferred to the electric machine.

[0017] During the rotation of the rotor, which is arranged radially within the stator, the stator experiences vibration excitation. To acoustically decouple the stator and thus improve its acoustic properties and reduce vibrations, radially oriented pins are provided between the roller elements. These pins bear tangentially against the roller elements and are movable in the radial direction relative to the housing. Consequently, the vibration excitations are completely decoupled from the housing, while simultaneously allowing for a relatively rigid support of the stator against the housing via the pins and roller elements. This ensures unrestricted functionality of the device or electric machine even without a fixed stator to the housing, while at the same time completely shielding the acoustic excitation from the housing.

[0018] Two preferred embodiments of the invention are explained in more detail below with reference to the drawings, wherein identical or similar elements are provided with the same reference numeral. Here, Fig. 1 a highly schematic cross-sectional representation of a planetary gear according to a first embodiment, Fig. 2 a highly schematic longitudinal section view of the planetary gear according to Fig. 1, Fig. 3 a highly schematic cross-sectional representation of an electrical machine according to a second embodiment, and Fig. 4 a highly schematic longitudinal section view of the electric machine according to Fig. 3.

[0019] According to Fig. 1 and Fig. Figure 2 shows a device designed as a planetary gear 1 in a highly schematic representation of a first embodiment. The exemplary planetary gear 1 comprises a sun gear 2, a cylindrical ring gear 3 with internal teeth, and a planet gear set with several planet gears 4, which are rotatably mounted, at least indirectly, on a planet carrier (not shown here). Fig. For the sake of simplicity, a representation of the planet gears 4 and the sun gear 2 is omitted in Figure 2.

[0020] Four radially outwardly extending pins 5 are evenly distributed on an outer circumferential surface 16 of the ring gear 3. In this case, two pins 5 are arranged essentially horizontally opposite each other on the ring gear 3, and two further pins 5 are arranged essentially vertically opposite each other on the ring gear 3, with the pins 5 being oriented as shown in Fig. 2 can be seen, extending over almost the entire axial length of the ring gear 3.

[0021] The pins 5 project radially into a respective recess 14 on the housing 7 and are arranged between two respective roller elements 6a, 6b, which are located in the respective recess 14 and enable tangential support of the ring gear 3 on the housing 7. Thus, a torque acting on the ring gear 3 can be supported tangentially on the housing 7 via the pins 5 and, depending on the direction of the torque, via the respective roller element 6a, 6b. Simultaneously, each pin 5 is movable in the radial direction relative to the housing 7, whereby the respective pin 5 can roll on the respective roller element 6a or 6b depending on the load or the radial deflection of the ring gear 3. In other words, the pins 5 do not come into contact with the housing 7 in the radial direction.The pins 5 only make contact with the roller elements 6a, 6b depending on an applied torque, so that a non-permanent contact between the pins 5 and the associated roller elements 6a, 6b and consequently an acoustic decoupling of the ring gear 3 from the housing 7 is achieved.

[0022] The roller elements 6a, 6b are cylindrical in shape, and their axial length corresponds essentially to the axial length of the pins 5. In particular, the roller elements 6a, 6b and the pins 5 are of the same length. Therefore, there is line contact between the pins 5 and the respective roller elements 6a, 6b. The roller elements 6a, 6b can thus come into contact with both the recess 14 of the housing 7 and the pin 5.

[0023] Furthermore, the journals 5 are pressed into recesses in the ring gear 3, which is not shown in detail here, thus simplifying and therefore reducing the cost of manufacturing both the journals 5 and the ring gear 3. Alternatively, it is conceivable to join the journals 5 to the ring gear 3 using a material-bonded connection, for example by welding.

[0024] The pins 5 and the roller elements 6a, 6b are also axially clamped in the housing 7, specifically, the pins 5 and the roller elements 6a, 6b bear axially on one side against a shoulder 8 of the housing 7, which is integrally connected to the housing 7, and on the other side against a thrust washer 10. The thrust washer 10 is secured in its axial position by a retaining ring 9 designed as a snap ring, which is received in a circumferential groove 15 on the housing 7.

[0025] To compensate for manufacturing tolerances and adjust the positioning of the ring gear 3 in space, roller elements 6a, 6b with different roller diameters can be used. Therefore, at least a proportion of the roller elements 6a, 6b have unequal outer diameters, thus achieving a backlash-free system.

[0026] As in the second embodiment according to Fig. 3 and Fig. As shown in Figure 4, which is highly schematic, acoustic decoupling can also be provided in an electric machine 12. In other words, the device is designed as an electric machine 12 and comprises a stator 13 and a rotor 11, partially shown, which is rotatable relative to it. The only difference from the previous embodiment is that the journals 5 are arranged on an outer circumferential surface 16 of the stator 13 and extend radially outwards from it, being positioned between two roller elements 6a, 6b to tangentially support the stator 13. The vibration decoupling mechanism operates analogously to the embodiments for the planetary gear 1 according to Figure 4. Fig. 1 and Fig. 2. Reference sign 1 planetary gear 2 sun wheel 3. Ring gear 4 planetary gear 5 cones 6a First role element 6b Second roller element 7 cases 8 Shoulder 9 retaining ring 10 Thrust washer 11 Rotor 12 Electric Machine 13 Stator 14 Recess on the housing 15 Nut 16 External perimeter area

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