FREEWHEEL

Abstract

A freewheel for changing a transmission characteristic of a planetary transmission for a motor vehicle transmission. The freewheel has a first ring which has a first blocking contour, a second ring which is rotatable relative to the first ring and which has a second blocking contour, tiltable blocking bodies which can be caused to engage into the first blocking contour and into the second blocking contour, and a switching element for tilting the blocking bodies. The switching element, in a blocking position, clamps the blocking bodies immovably to the first blocking contour and to the second blocking contour, in a freewheel position, allows unidirectional freewheeling, and in an inactive position, holds the blocking bodies down on the first ring so as to be spaced apart from the second ring.

Claims

1. A freewheel for changing a transmission characteristic of a planetary transmission for a motor vehicle transmission, said freewheel comprising: a first ring which has a first blocking contour, a second ring which is rotatable relative to the first ring and which has a second blocking contour, tiltable blocking bodies which are configured to engage into the first blocking contour and into the second blocking contour, and a switching element for tilting the blocking bodies, wherein, in a blocking position of the switching element, the switching element clamps the blocking bodies immovably to the first blocking contour and to the second blocking contour, wherein, in a freewheel position of the switching element, the switching element allows unidirectional freewheeling, and wherein, in an inactive position of the switching element, the switching element holds the blocking bodies down on the first ring so as to be spaced apart from the second ring.

2. The freewheel as claimed in claim 1, wherein the second blocking contour has (i) a slide ramp, which, in the freewheel position, is configured to be caused to slide in one circumferential direction on the blocking body, and (ii) a blocking stop, which is configured to be caused to abut in the other circumferential direction against the blocking body in order to block a rotational movement of the first ring with the second ring.

3. The freewheel as claimed in claim 1, wherein the switching element has a (i) blocking ramp, which acts in one circumferential direction so as to set the blocking element upright into the second blocking contour, and (ii) a holding contour, which acts in the other circumferential direction so as to hold the blocking element down against the first blocking contour.

4. The freewheel as claimed in claim 1, wherein the switching element is coupled to an electromechanically actuatable actuator for rotating the switching element.

5. The freewheel as claimed in claim 4, wherein the actuator is configured to switch the switching element in a manner dependent on a switching state of a clutch for rotationally conjointly connecting two transmission components of the planetary transmission.

6. The freewheel as claimed in claim 4, wherein the actuator has a rotatable switching drum with a guide groove which runs in closed fashion in a circumferential direction, wherein the switching element has a guide pin which is inserted in the guide groove, wherein an axial relative movement of the guide pin with respect to the switching drum can be converted in the guide groove into a limited rotational movement of the switching element along the circumferential direction.

7. The freewheel as claimed in claim 6, wherein the switching drum has a further guide groove, which runs in closed fashion in the circumferential direction, for actuating a clutch element, friction clutch and/or brake that is/are configured to engage on a transmission component of the planetary transmission.

8. A motor vehicle transmission for coupling an electric machine to a drivetrain of an electrically driveable motor vehicle having (a) a planetary transmission for converting a torque that can be introduced by the electric machine, wherein the planetary transmission has (i) a sun gear, (ii) a ring gear arranged coaxially with respect to the sun gear, (iii) at least one planet gear which meshes with the sun gear and with the ring gear, and (iv) a planet carrier which bears the planet gear, (b) a clutch for rotationally conjointly connecting the ring gear to the planet carrier, and (c) the switchable freewheel as claimed in claim 1, wherein, during traction operation, the freewheel is configured to selectively bring about freewheeling and/or blocking of the sun gear with respect to a static housing.

9. The motor vehicle transmission of claim 8, wherein the planetary transmission is operable as a transmission with 2 gear ratios.

Description

BRIEF DESCRIPTION OF THE DRAWING FIGURES

[0018] The invention is explained below by way of example with reference to the appended drawings on the basis of preferred exemplary embodiments, wherein the features presented below may in each case individually or in combination represent an aspect of the invention, in which:

[0019] FIG. 1 shows a schematic developed side view of a part of a freewheel in a blocking position,

[0020] FIG. 2 shows a schematic developed side view of the freewheel from FIG. 1 in a freewheel position, and

[0021] FIG. 3 shows a schematic developed side view of the freewheel from FIG. 1 in an inactive position.

DETAILED DESCRIPTION OF THE INVENTION

[0022] The freewheel 10 illustrated in a simplified illustration in FIG. 1 has a first ring 12, which is configured for example as an outer ring, and a second ring 14, which is configured coaxially with respect to the first ring 12 and so as to be relatively rotatable and for example as an inner ring. The freewheel 10 can be installed in a planetary transmission of a motor vehicle transmission in order, by means of a selective coupling of a transmission component of the planetary transmission to a housing, to change a transmission ratio of the planetary transmission and thus engage a different transmission gear ratio. For example, the first ring 12 is connected to the housing, whereas the second ring is connected to a sun gear of the planetary transmission.

[0023] The first ring 12 has a first blocking contour 16, in which a blocking body 18 configured as a pawl is mounted so as to be tiltable. The blocking body 18 can in particular be preloaded by means of a spring element in one of the tilting directions of the blocking body 18, in particular in the direction of the second ring 14. The second ring 14 has a second blocking contour 20 into which the free end of the blocking body 18 can engage. When the rings 12, 14 are arranged in a common axial region, the blocking contours 16, 20 can point toward one another in a radial direction. When the rings 12, 14 are arranged adjacent to one another in an axial direction, the blocking contours 16, 20 can point toward one another in an axial direction. The second blocking contour 20 has, on one tangential side, a slide ramp 22 on which the blocking body 18 can slide during a relative rotation without blocking the second ring 14 with the first ring 12 for a transmission of torque. On the opposite tangential side, the second blocking contour 20 has a blocking stop 24 on which the the blocking body 18 can abut during an oppositely directed relative rotation and blocks the second ring 14 with the first ring 12 for a transmission of torque.

[0024] Provided between the first ring 12 and the second ring 14 is a rotatable switching element 26 for switching different operating modes for the freewheel 10. In the blocking position illustrated in FIG. 1, the switching element 26 lies with a blocking ramp 28 against the blocking body 18, such that the blocking body 18 is held immovably between the blocking ramp 28 of the switching element 26 and the slide ramp 22 of the second blocking contour 20. In the blocking position, the freewheel can transmit a torque, and couple the first ring 12 fixedly in terms of movement to the second ring 14, in both relative directions of rotation.

[0025] In the freewheel position illustrated in FIG. 2, the switching element 26 is positioned in a circumferential direction between two blocking bodies 18 without interacting with the blocking bodies 18. In the freewheel position, the blocking body 18 that can be caused to engage into the second blocking contour 20 can, in one relative direction of rotation, slide on the slide ramp 22 of the second blocking contour 20 and freewheel, whilst in the opposite relative direction of rotation, the blocking body 18 abuts against the blocking stop 24 of the second blocking contour 20 and blocks the first ring 12 with the second ring 14 in torque-transmitting fashion.

[0026] In the inactive position illustrated in FIG. 3, the switching element 26 has, by means of a holding contour 30 pointing away from the blocking ramp 28, pushed the blocking body 18 into the first blocking contour 16, such that the blocking body 18 has been held out of the second blocking contour 20. In this way, a transmission of torque between the first ring 12 and the second ring 14 is interrupted, and freewheeling is provided, in both relative directions of rotation.