Abstract
An eccentric gear unit for a braking force generator. The eccentric gear unit includes an input shaft with an eccentric, which input shaft can be rotated about an axis of rotation, wherein the eccentric is mounted in a central hole of a cam which rolls on a ring gear, and wherein the cam is coupled to an output shaft which is coaxial with the input shaft, via coupling arrangement which includes at least one pin which engages in an opening of the cam. A braking force generator having an eccentric gear unit is also provided.
Claims
1-10. (canceled)
11. An eccentric gear unit for a braking force generator, comprising: an input shaft having an eccentric, the input shaft being rotatable about an axis of rotation, wherein the eccentric is mounted in a central hole of a cam which rolls on a ring gear, and wherein the cam is coupled to an output shaft which is coaxial with the input shaft, via a coupling arrangement which includes at least one pin which engages in an opening of the cam.
12. The eccentric gear unit according to claim 11, wherein the cam is operatively connected to the ring gear via a geometry, the geometry being a gear-tooth geometry or a cycloid geometry.
13. The eccentric gear unit according to claim 11, wherein the at least one pin is part of the output shaft or is integrally connected to the output shaft, wherein the output shaft has a plurality of pins arranged at a same angular distance from one another.
14. The eccentric gear unit according to claim 11, wherein the at least one pin includes a plurality of pins, and wherein the cam has a plurality of openings arranged at a same angular distance from one another, and a pin of the plurality of pins engages in each opening.
15. The eccentric gear unit according to claim 11, wherein the at least one opening has an inner contour that deviates from a circular shape and/or the at least one pin has an outer contour that deviates from the circular shape.
16. The eccentric gear unit according to claim 11, wherein the at least one pin is in multiple parts and has a main body and a sliding body arranged on the main body, wherein the sliding body has an outer contour that deviates from a circular shape.
17. The eccentric gear unit according to claim 16, wherein the eccentric and/or the cam and/or the ring gear and/or the at least one pin and/or the at least one sliding body is at least partially made of a plastic material.
18. The eccentric gear unit according to claim 11, wherein the input shaft has at least one further eccentric which is mounted in a central hole of a further cam which rolls on the ring gear, wherein an angular position of the further eccentric is offset by an angle with respect to an angular position of the eccentric.
19. A braking force generator, comprising: an eccentric gear unit including an input shaft having an eccentric, the input shaft being rotatable about an axis of rotation, wherein the eccentric is mounted in a central hole of a cam which rolls on a ring gear, and wherein the cam is coupled to an output shaft which is coaxial with the input shaft, via a coupling arrangement which includes at least one pin which engages in an opening of the cam; wherein the eccentric gear unit is configured to couple an electric motor to a screw or spindle drive.
20. The braking force generator according to claim 19, wherein the output shaft of the eccentric gear unit forms an element to be driven of the screw or spindle drive.
21. The braking force generator according to claim 20, wherein the element to be driven is a spindle nut.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] FIG. 1 is a schematic cross-sectional view through an eccentric gear unit according to the present invention in accordance with a first preferred example embodiment.
[0026] FIG. 2 is a schematic cross-sectional view through an eccentric gear unit according to the present invention in accordance with a second preferred example embodiment.
[0027] FIG. 3 shows a schematic longitudinal section through the eccentric gear unit of FIG. 2.
[0028] FIG. 4 is a schematic cross-sectional view through an eccentric gear unit according to the present invention in accordance with a third preferred example embodiment.
[0029] FIG. 5 is a schematic cross-sectional view through an eccentric gear unit according to the present invention in accordance with a fourth preferred example embodiment.
[0030] FIG. 6 is an exploded view of the eccentric gear unit of FIG. 5.
[0031] FIG. 7 is an exploded view of the output elements of an eccentric gear unit according to the present invention in accordance with a fifth preferred example embodiment.
[0032] FIG. 8 is a perspective view of an output shaft for an eccentric gear unit according to an example embodiment of the present invention.
DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS
[0033] The eccentric gear unit 1 according to the present invention shown in FIG. 1 has an input shaft 2 with an eccentric 3 which is connected to the input shaft 2 for conjoint rotation. The eccentric 3 is rotatably mounted in a central hole 4 of a cam 6 which is surrounded by a ring gear 5. During operation of the eccentric gear unit 1, the cam 6 rolls on the ring gear 5. A plurality of openings 7 is formed in the cam 6, which openings are arranged at the same angular distance relative to one another around the central hole 4. Each opening 7 receives a pin 8 of which the cross section is smaller than the opening cross section of the relevant opening 7. The pins 8 thus come to rest against the cam 6 only in a limited contact region in each case, wherein the contact region moves with the rolling movement of the cam 6. In this way, the cam 6 transmits torque to an output shaft 9, which is firmly connected to the pins 8. In FIG. 1, power is transmitted from the cam 6 to the ring gear 5 via a geometry 10, which in this case is designed as a gear-tooth geometry analogous to involute toothing.
[0034] FIGS. 2 and 3 show a further eccentric gear unit 1 according to the present invention. This comprises two eccentrics 3 and two cams 6. In this way, the load can be reduced by half. At the same time, any imbalance of an eccentric 3 can be compensated for. For this purpose, the two eccentrics 3 are arranged axially one behind the other and offset from one another in their angular position. The same applies to the two cams 6, so that each pin 8 engages in openings 7 of the two cams 6. Thereby, the pins 8 come to rest against the two cams 6 in two opposite contact regions. The output via the pins 8 enables the input shaft 2 and the output shaft 9 to rotate about a common axis of rotation A. With the eccentric gear unit 1 of FIGS. 2 and 3, the cams 6 are also operatively connected to the ring gear 5 via an undulating geometry 10.
[0035] FIG. 4 shows a further preferred embodiment of an eccentric gear unit 1 according to the present invention. In contrast to the eccentric gear units 1 described above with reference to FIGS. 1 to 3, this eccentric gear unit has pins 8 in multiple parts. Each pin 8 has a main body 16 and a sliding body 13 arranged on the main body 16, via which the pin 8 engages in the relevant opening 7 of the two cams 6. The multi-part design of the pins 8 enables particularly favorable material pairings. For example, the main body 16 can be made of metal and the sliding body 13 can be made of plastics material. A damping effect can be achieved via the sliding bodies 13 made of plastics material, which minimizes load peaks. At the same time, the plastics material improves the tribological properties.
[0036] The multi-part design of the pins 8 shown in FIG. 4 can also be implemented in the eccentric gear units 1 of FIGS. 1 to 3.
[0037] FIG. 5 shows a further embodiment of an eccentric gear unit 1 according to the present invention. Here as well, the pins 8 are in multiple parts. The sliding bodies 13 which engage in the openings 7 of the cam 6 in each case have an outer contour 14 that deviates from the circular shape. Thereby, the outer contour 14 of the sliding bodies 13 is adapted to an inner contour 11 of the openings 7 that deviates from the circular shape. The geometries deviating from the circular shape increase the surface contact between the pins 8 and the cam 6, which reduces the surface pressure in the region of the openings 7 and thus the load on the cam 6. The openings 7 are selected to be sufficiently large so that a gap s remains between the sliding bodies 13 and the cam 6, which ensures that the cam 6 can roll on the ring gear 5.
[0038] It can be seen from FIG. 6 that, with the eccentric gear unit 1 of FIG. 5, the main bodies 16 of the pins 8 are formed in one piece with the output shaft 9. As shown by way of example in FIG. 7, this is not necessarily the case. Here, the main bodies 16 are produced separately and, once produced, are integrally connected to the output shaft 9. In FIG. 7, the output shaft 9 also forms an element 15 to be driven of a screw or spindle drive, which is not shown further. The element 15 can, for example, be a spindle nut of a spindle drive. In this way, the number of parts of the spindle drive can be reduced or the spindle drive can be simplified.
[0039] Instead of the multi-part design of the output elements shown in FIG. 7, the output elements can also be formed by a single component—as shown by way of example in FIG. 8. In FIG. 8, the output shaft 9 also forms the pins 8. The pins 8 may have a circular outer contour 12 or, according to the illustration of FIG. 8, each may have an outer contour 12 that deviates from the circular shape. In the latter case, the pins 8 engage in openings 7 of a cam 6, each of which has an inner contour 11 that deviates from the circular shape (not shown). The one-piece design of the output elements also enables the output shaft 9 to be used at the same time as the element 15 to be driven of a screw or spindle drive, which is not shown in more detail.
