CN112119244A

CN112119244A - Two-speed transmission for electrically driven motor vehicle

Info

Publication number: CN112119244A
Application number: CN201980030490.0A
Authority: CN
Inventors: 普斯·萨蒂亚纳拉亚纳; 普拉若·艾亚帕特
Original assignee: Schaeffler Technologies AG and Co KG
Current assignee: Schaeffler Technologies AG and Co KG
Priority date: 2018-07-31
Filing date: 2019-06-11
Publication date: 2020-12-22
Also published as: WO2020025077A1; DE102018118548A1

Abstract

The invention relates to a two-speed transmission (10) for an electrically driven motor vehicle, in particular an electric scooter, having: an input shaft (12) for introducing torque; an output shaft (18) for transferring the torque; a first gear stage (14); a second gear stage (16); a sliding sleeve (28) which is guided on the input shaft (12) or on the output shaft (18) in a rotationally fixed but axially displaceable manner for producing a form-locking connection with a first gearwheel (20) of the first gear stage (14) and/or with a second gearwheel (24) of the second gear stage (16); and an operating actuator (40) having extendable actuating fingers (38) for axially displacing the sliding sleeve (28), wherein the sliding sleeve (28) has sliding ramps (42, 44) which extend in the circumferential direction and are angled relative to a radial plane for turning at the extended actuating fingers (38) of the operating actuator (40). In order to prevent damage or noise during the changeover, the sliding ramps (42, 44) are designed to be axially resilient, so that a comfortable power transmission can be carried out in the electrically driven motor vehicle.

Description

Two-speed transmission for electrically driven motor vehicle

Technical Field

The invention relates to a two-speed transmission for electrically driven motor vehicles, by means of which the power of an electric machine can be converted.

Background

Electric vehicles will become more and more important in the future. Two-speed transmissions are useful for achieving acceleration and hill climbing on the one hand, and for increasing the top speed on the other hand, particularly for two-wheeled vehicles such as electric bicycles, electric mopeds, scooters, electric bicycles, mopeds, motorcycles or tricycles (such as rickshaws). For example, to take advantage of the characteristic starting capability of brushless dc motors, it is proposed to use a clutchless two-speed transmission.

When accelerating an electrically driven motor vehicle from a pivot start, the electric machine may first accelerate from a standstill to a basic speed with a substantially constant torque. When the basic speed is reached, the driving power of the motor remains substantially constant, so that the torque decreases with increasing rotational speed. To achieve large torque and speed profiles, two-speed transmissions provided with different gear ratios may be provided. Thus, a high gear ratio can be provided in the low speed range in order to provide as high a torque as possible for acceleration, and in addition a low gear ratio can be provided in the high speed range so that as high a vehicle speed as possible can be achieved. However, a shift from one transmission ratio to another can lead to an interruption in the tractive force, which is perceived as a loss of comfort and should be avoided.

DE 102012221056 a1 discloses a shifting device with a claw clutch, in which an actuator displaces a sliding sleeve axially by means of a shift gate. However, this document is not of the type in question, since this is not a two-speed transmission.

With such a transmission, the pawls of the sliding sleeve may not engage exactly in the intended openings of the gear wheels during gear shifting, but rather strike the gear wheel body first. The actuator fingers may then jump out of the shift gates or bend. In addition to this damage, the transmission is also loud.

Disclosure of Invention

The object of the present invention is to disclose measures that enable comfortable transmission of power (without noise and damage) in an electrically driven motor vehicle.

According to the invention, this object is achieved by a two-speed transmission having the features of claim 1. Preferred embodiments of the invention are set forth in the dependent claims and in the description below, each of which can represent an aspect of the invention either individually or in combination.

According to the invention, a two-speed transmission for an electrically driven motor vehicle, in particular an electric scooter, is provided, having: an input shaft connectable to the motor for introducing torque; an output shaft connectable to the drive wheels for transferring torque; a first gear stage for transmitting the rotational speed of the input shaft to the output shaft at a first gear ratio; a second gear stage for transmitting the speed of the input shaft to the output shaft at a second gear ratio different from the first gear ratio; a sliding sleeve which is guided in a rotationally fixed but axially displaceable manner on the input shaft or on the output shaft for producing a form-locking connection with a first gear wheel of the first gear stage and/or a second gear wheel of the second gear stage; and an operating actuator having extendable actuating fingers for axially displacing the sliding sleeve, wherein the sliding sleeve has a sliding ramp which extends in the circumferential direction and is angled relative to a radial plane for turning over the extended actuating fingers of the operating actuator, and wherein the sliding ramp is axially resilient.

If a gear change is to be made between a first gear formed by the first gear stage and a second gear formed by the second gear stage, it is sufficient to extend the actuating finger of the operating actuator. In the extended position of the actuating finger, the actuating finger may be in lateral contact with the at least one sliding ramp. The operating actuator and thus the actuating finger is generally fixed in the axial direction of the sliding sleeve, while the sliding sleeve is axially displaceable. Thus, during relative rotation of the sliding sleeve with the input shaft or with the output shaft relative to the projecting actuating fingers, the sliding sleeve is forced to be axially displaced if the sliding ramp (which is angled relative to the radial plane of the sliding sleeve) slides over the actuating fingers. The sliding sleeve can thus be connected in a form-fitting manner to one gear wheel and can be moved in the axial direction to the other gear wheel. The sliding sleeve can be axially displaced until the sliding sleeve forms a form-fitting connection with the other gear. The actuating finger can be moved into the retracted position at the latest when the sliding sleeve is positively coupled to the further gear wheel. For a downshift, the actuating finger can be reextended and engage another sliding ramp and/or in an angular region of the sliding ramp which is offset in the circumferential direction and is shaped for axial displacement of the sliding sleeve in the opposite axial direction.

With an actuating finger which can slide on a sliding ramp, it is possible to carry out the axial displacement of the sliding sleeve required for shifting gears within a particularly small angular range of relative rotation of the sliding sleeve with respect to the actuating finger. This means that the shaft, the input shaft or the output shaft coupled to the sliding sleeve rotates less than a full revolution before the switching process between the first gear and the second gear is completed. This results in a very rapid gear change, without the driver of the motor vehicle perceiving a traction force interruption which reduces the comfort. At the same time, the two gear stages make it possible to provide a larger torque range and a larger rotational speed range and/or to make the electric machine smaller, compared to a rigid transmission using an electric machine coupled to the input shaft. The actuating finger (which can slide on a sliding ramp) enables a very rapid shifting of the two-speed transmission using the shifting sleeve, so that a comfortable power transmission can be achieved in an electrically driven motor vehicle.

Since the sliding ramp is resilient, nothing happens if the pawl does not immediately engage exactly in the intended opening on the gear, but first contacts the material of the gear. The sliding ramp then yields axially, but increases the axial pressure on the claws due to its elastic deformation, so that the claws can later engage positively, but without causing any damage and without generating any noise. The driver does not even notice a brief delay, because the frictional connection occurs after a very short relative rotation of the shift sleeve and the gear wheel. The resilient nature of the sliding ramp will store energy for a short period of time and prevent hard hits or damage to the actuating finger. The pre-stress or stored energy during non-engagement will be stored for a short time and then immediately restored when the jaws and opening are mated together and the jaws are engaged. This allows a quieter and smooth switching process and protects the entire system against overload.

Furthermore, the present invention minimizes excessive friction at the contact points between the actuation finger and the sliding ramp and between the shifting sleeve pawls and the gear. If not aligned during shifting, the sliding ramp spring will absorb the additional load and store it for later use. If the pawl and opening are properly aligned with each other, the stored energy will ensure good engagement in the other gears.

Therefore, the present invention reduces the impact or knocking and contributes to the comfort since the noise generated is small. According to the invention, the elastic gentle shifting also prevents overloading and breakage of the components. This can extend the useful life of the transmission.

A brushless dc motor is preferably used as the motor for the input shaft of the transmission according to the invention. The characteristics of a brushless dc motor are particularly suited to transmissions that include gear sets and sliding sleeves.

In particular, the sliding sleeve has: a first sliding ramp extending in a circumferential direction and angled relative to a radial plane for displacing the sliding sleeve away from the first gear; and a second sliding ramp extending in the circumferential direction and angled with respect to the radial plane for displacing the sliding sleeve away from the second gear, wherein the first sliding ramp and the second sliding ramp are arranged opposite each other in the axial direction to delimit a guide slot formed in the sliding sleeve for receiving a protruding actuation finger of the operating actuator. The actuating finger is slidable on the first sliding ramp for shifting the second gear and slidable on the second sliding ramp for shifting the first gear. The first and second sliding ramps may constrain sidewalls of the guide slot such that the actuation finger may extend into the guide slot formed in the shift sleeve in the extended position. Thus, the actuation fingers need not engage the outer axial side of the actuation sleeve. Instead, the outer axial side of the actuating sleeve is only available for a form-fitting connection with the designated gear in each case. The shift sleeve can be kept axially small, so that the space requirement of the two-speed transmission is correspondingly small. Due to the axial offset of the first sliding ramp relative to the second sliding ramp, it is not necessary to arrange the first sliding ramp and the second sliding ramp one behind the other in the circumferential direction within the offset angular range. It is therefore not necessary to detect the angular position of the sliding sleeve relative to the actuating finger, so that the actuating finger can engage the desired sliding ramp and does not immediately cancel the desired axial displacement of the sliding sleeve. Instead, it is possible to extend the actuating finger as far as possible so that it can slide on the correct sliding ramp. Two or more sliding ramps may be used.

Advantageously, the actuation finger of the operating actuator is movable substantially in the radial direction of the sliding sleeve between an extended position, in which the actuation finger is in contact with the sliding ramp, and a retracted position, in which the actuation finger is positioned radially offset with respect to the sliding ramp. Thus, the operating actuator can be easily positioned in the axial direction between the first gear stage and the second gear stage in a common axial region with the sliding sleeve. This results in a two-speed transmission with little axial space requirements.

Preferably, a lifting ramp (which extends in the circumferential direction and is angled in the circumferential direction) adjoins the sliding ramp for automatically moving the actuating finger from the extended position to the retracted position, wherein in particular the lifting ramp starts at the circumferential angle of the sliding ramp and the extended actuating finger has axially displaced the sliding sleeve to a maximum or minimum extent. When the actuation finger has slid on the sliding ramp in order to cause the desired axial displacement of the sliding sleeve, the actuation finger can be automatically pushed into the retracted position in the circumferential direction by the lifting ramp. Unnecessary lateral grinding of the actuating finger on the sliding ramp can be avoided. In addition, the reaction force exerted by the lifting ramp on the actuating finger, in particular in the longitudinal direction of the operating actuator, can be easily determined by the operating actuator and can in particular automatically trigger a switching state in the operating actuator which moves the actuating finger into the retracted position. In particular, in the retracted position, the actuating finger is spaced apart from the lifting ramp, so that unnecessary grinding contact of the actuating finger on the lifting ramp is also avoided. As long as an axial displacement of the sliding sleeve is necessary, the actuation finger is in contact with the sliding ramp only via the lifting ramp, so that unnecessary frictional relative movements and/or undesired actuation of the sliding sleeve are avoided.

The resilient sliding ramp may be made of any suitable resilient material. The resilient sliding ramp may be made of a resilient plastic with or without reinforcement, for example using glass and/or carbon fibre. However, the resilient sliding ramp is preferably made of metal, such as spring steel, steel sheet or metal sheet.

The sliding ramp is preferably configured in an annular manner and is provided at its axially protruding point with a radially further inner opening which allows the radially outer part of the sliding ramp to move elastically in the axial direction relative to the actual body of the sliding ramp and to yield during operation if the pawl cannot be made to engage immediately in the provided opening. The opening is preferably arcuate and preferably extends over half of the circumference of the sliding ramp. Then, the radially outwardly farther opening and the elastic edge of the sliding ramp are shaped like a semi-circular arc. An optimum spring effect of the axially projecting ramp arranged there is achieved.

Specifically, the sliding ramp has: a forward ramp for axially displacing the sliding sleeve upon rotation of the sliding sleeve in a first circumferential direction relative to the actuation finger; and a rearward ramp for axially displacing the sliding sleeve when the sliding sleeve is rotated relative to the actuating finger in a second circumferential direction opposite to the first circumferential direction, and wherein in particular the forward and rearward ramps merge into each other at a circumferential angle of the sliding ramp and the projecting actuating finger has axially displaced the sliding sleeve to a maximum extent. This makes it possible to change between the gears of the two-speed transmission both when the motor vehicle is traveling forward and when the motor vehicle is traveling backward. For this purpose, the forward ramp and the backward ramp may be in mirror image relation to each other, in particular the forward ramp and the backward ramp rest against each other at their highest height.

The sliding ramp is preferably arranged on the outside of the sliding sleeve. If two sliding ramps are used, each sliding ramp is on a different side. For example, one sliding ramp is opposite the gear set in the first gear and the other sliding ramp is opposite the gear set in the second gear.

The sliding ramp is preferably firmly connected to the sliding sleeve. This can be done by any joining method known per se, preferably by pressing or pressing.

The operating actuator preferably has a solenoid for magnetically displacing the actuating finger. The operating actuator can thus be configured as an electromagnetic actuator. The actuating finger can be moved between the retracted position and the extended position in a simple manner.

Particularly preferably, the sliding sleeve has: a first blocking ramp extending in a circumferential direction and angled in an axial direction for locking the sliding sleeve with the first gear; and/or a second blocking ramp extending in the circumferential direction and angled in the axial direction for locking the sliding sleeve with the second gear, wherein one blocking element is provided which engages with the first blocking ramp and/or the second blocking ramp in order to exert a blocking force on the component in the axial direction. The blocking element can exert a blocking force, in particular a spring force, for example in the radial direction, a portion of which acts in the axial direction by means of a blocking ramp serving as an inclined plane. The axial component of the blocking force can push the sliding sleeve into a blocking position in which it is positively connected to the gear wheel and/or blocks it in the blocking position. In particular, the locking sleeve can be pushed towards the gear wheel by the blocking force until after the slipping operation, if applicable, the rotational speed of the sliding sleeve being synchronized with the rotational speed of the gear wheel and a form-fitting connection being established between the sliding sleeve and the associated gear wheel. For this reason, it is not necessary for the actuating finger to slide on the sliding ramp.

In particular, the blocking element is designed as a rolling body, in particular as a ball, which is prestressed by a spring element, wherein in particular the blocking element is accommodated in the input shaft or the output shaft so as to be displaceable in the radial direction. If the blocking element is pushed particularly strongly against the spring force of the spring element (in particular in the form of a helical compression spring) at the beginning of the blocking ramp, a correspondingly high blocking force is applied to the blocking ramp in order to bring about a form-fitting connection of the sliding sleeve with the gear wheel. Once the form-fitting connection is brought about, the blocking element engages the end of the blocking ramp with a correspondingly small blocking force, which is particularly dimensioned such that the sliding sleeve can be held in the blocking position under the expected force. At the same time, the blocking force can be sufficiently small that the rolling bodies can sink into the shaft against the spring force of the spring element when the actuating finger engages the sliding ramp to axially displace the sliding sleeve. The rolling bodies can slide with substantially negligible friction on the blocking ramp. In particular, the rolling bodies are inserted in blocking positions into recesses which open radially inward and in which the blocking ramps form the sides of the associated recess.

Preferably, the axial displacement of the sliding sleeve between the first blocking position, in which the sliding sleeve is positively connected to the first gear wheel, and the second blocking position, in which the blocking element engages the first blocking ramp, and the second blocking position, in which the sliding sleeve is positively connected to the second gear wheel, and/or the axial displacement of the sliding sleeve between the second blocking position, in which the blocking element engages the second blocking ramp, and the first synchronization position, in which the blocking element engages the second blocking ramp, can be bridged by the axial displacement of the sliding sleeve when the actuating finger slides on the sliding ramp. Thus, the axial displacement of the sliding sleeve during shifting is provided by two different sources. First, an actuator finger sliding on the sliding ramp may axially displace the sliding sleeve to such an extent that the blocking element no longer engages the blocking ramp, the blocking element remaining engaged in the blocking position. The actuation finger may then slide further on the sliding ramp, moving the sliding sleeve until the blocking element engages the other blocking ramp. In this position of the sliding sleeve, the actuating finger can be brought into a retracted position, in which the remaining axial displacement of the sliding sleeve for shifting the other gear is caused by the blocking element sliding on the blocking ramp. Thus, the actuation finger need only move the sliding sleeve to such an extent that the blocking element engages the other blocking ramp. This ensures in particular that the sliding sleeve cannot become jammed between the actuating finger and the gear wheel of the gear to be shifted if the angular position of the sliding sleeve relative to the gear wheel is not yet sufficient to establish a form-fitting connection.

In particular, a control device may be provided which is designed to automatically shift gears when a certain predetermined threshold driving speed of the motor vehicle is exceeded and/or not reached and/or when a certain predetermined threshold torque of the input shaft is exceeded and/or not reached. Thus, the appropriate gear ratio can be automatically switched for a particular driving situation without the need for the driver of the motor vehicle to manually operate.

Drawings

The present invention is illustrated by way of example in the accompanying drawings which use preferred exemplary embodiments, in which features shown below are capable of representing one aspect of the invention both in isolation and in combination. In the drawings:

figure 1 shows a schematic cross-sectional view of a two-speed transmission with a shifted first gear,

figure 2 shows a perspective view of a sliding sleeve and sliding ramp for the two-speed transmission of figure 1,

figure 3 shows a schematic view of another embodiment of a two-speed transmission in first gear,

FIG. 4 shows a schematic cross-sectional view of the two-speed transmission of FIG. 3 in a second gear.

Detailed Description

The two-speed transmission 10 shown in fig. 1 has an input shaft 12 that can be connected for common rotation to a motor shaft of a motor vehicle, particularly an electric scooter. The input shaft 12 may be coupled to an output shaft 18 via a first gear stage 14 and a second gear stage 16 having different gear ratios to drive wheels of a motor vehicle coupled to the output shaft 18. The first gear stage 14 has a first gear wheel 20 which is axially attached to the input shaft 12 as an idler wheel in a substantially immovable manner and meshes with a first fixed gear wheel 22 which is fixedly connected to the output shaft 18. The second gear stage 16 has a second gear wheel 24, which is axially attached to the input shaft 12 in a substantially immovable manner as an idler wheel and meshes with a second fixed gear wheel 26 fixedly connected to the output shaft 18. Between the first gear wheel 20 and the second gear wheel 24, a sliding sleeve 28 is connected to the input shaft 12 in a non-rotatable but axially displaceable manner. Alternatively, the sliding sleeve 28 and the

gears

20, 24 configured as idler gears may be provided on the output shaft 18, while the fixed gears 22, 26 are connected to the input shaft 12.

The sliding sleeve 28 has, on its axial side facing the first gear wheel 20, a projecting first claw 30 which can be positively engaged in a first opening 32 of the first gear wheel 20 in order to shift the first gear of the first gear stage 14, as shown in fig. 1. The sliding sleeve 28 therefore has, on its axial side facing the second gear wheel 24, a projecting second claw 34 which can engage in a form-fitting manner in a second opening 36 of the second gear wheel 24 in order to shift the second gear of the second gear stage 16. To axially displace the sliding sleeve 28, the actuation finger 38 of the operating actuator 40 may transversely engage the first sliding ramp 42 or the second sliding ramp 44. After the sliding sleeve 28 has been axially displaced, the protruding actuation fingers 38 can be pushed radially outward into the retracted position by the lifting ramps 46. A radially oriented blocking element 48 is embedded in the input shaft 12 and pushes the ball 52 radially outwards via a spring element 50 designed as a compression spring against a first blocking ramp 54 or a second blocking ramp 56 of the sliding sleeve 28.

When the sliding sleeve 28 is coupled to the first gear wheel 20 in a form-fitting manner, the sliding sleeve 28 is locked by the blocking element 48 engaging with the second blocking ramp 54, wherein this locking can be overcome by the actuating finger 38 sliding on the first sliding ramp 42 in order to shift into the second gear. The sliding sleeve 28 is axially displaced by the actuation finger 38 to such an extent that the blocking element 48 engages the first blocking ramp 54. In this case, the actuating finger 38 can be moved into a retracted position, in which for the remaining axial path the sliding sleeve 28 can be displaced by the spring force of the blocking element 48 to establish a form-fitting connection with the second gear wheel 24.

As shown in fig. 2, the first sliding ramp 42 may have a forward ramp 58 and a rearward ramp 60 arranged in a mirror-inverted manner. When the sliding sleeve 28 rotates with the input shaft 12 in the first circumferential direction relative to the actuating finger 38 when the motor vehicle is traveling forward, the forward ramp 58 may slide to axially displace the sliding sleeve 28 on the actuating finger 38. When the sliding sleeve 28 is rotated together with the input shaft 12 in a second circumferential direction opposite to the first circumferential direction relative to the actuating finger 38 when the motor vehicle is reversing, the actuating finger 38 can slide on the rearward ramp 60 in order to axially displace the sliding sleeve 28. The second sliding ramp 44 may be designed in a mirror-inverted manner with respect to the first sliding ramp 42. The first sliding ramp 42 and the second sliding ramp 44 may laterally define a guide slot formed therebetween into which the actuation finger 38 may extend in a radial direction to slide on the first sliding ramp 42 or the second sliding ramp 44 in the extended position.

As can be seen from fig. 2, the first sliding ramp 42 and the second sliding ramp 44 may have an annular design and may be pressed on both sides of the sliding sleeve 28. The

ramps

42 and 44 form guide slots for the actuating fingers 38. The forward ramps 58 and the rearward ramps 60 project inwardly and, during rotation, the sliding sleeve is displaced axially to the right or left under the action of the projecting actuating fingers 38, thereby releasing the frictional connection from one gear stage (e.g., 14) and producing the frictional connection relative to the other gear stage (e.g., 16). Since the

ramps

58 and 60 are resilient according to the invention, a knocking or striking of the actuating finger 38 is prevented.

The arcuate openings 62 of the sliding

ramps

42 and 44 are clearly visible, which are arranged radially inside the forward ramp 58 and the rearward ramp 60 and allow the two projecting

ramps

58 and 60, which are arranged further radially outward, to deflect and thus prevent too much force from being applied to the actuating finger 38 and bending or breaking it, since the claws 30 and 34 are not engaged in their

openings

32 and 36. The

elastic regions

58 and 60 then yield axially, but due to their elastic force the axial force of the sliding sleeve 28 increases and thus pushes the pawls 30 or 34 in a slightly further rotated manner into their corresponding

openings

32 or 36 in order to cause a gear shift. Possible axial deflections (without damaging anything) can reach several centimeters, but are preferably in the range of several millimeters during operation.

Fig. 3 shows a schematic diagram of another embodiment of the two-speed transmission 10 in first gear. The construction is similar to that of fig. 1, but the sliding sleeve 28 is not located on the input shaft 12 but on the output shaft 18, and the reduction of the two

gear stages

14 and 16 is achieved by selecting the gear size. In fig. 3, the first (smaller) gear 14 is engaged by moving the sliding sleeve 28 to the upper left corner, where it transmits power from the input shaft 12 to the output shaft 18 via the

gears

26 and 24. This creates high torque and facilitates starting and uphill driving.

Fig. 4 shows the two-speed transmission 10 of fig. 3 in a second gear. Here, by moving the sliding sleeve 28 to the lower right corner, the second (larger) gear 16 is engaged, which here transmits power from the input shaft 12 to the output shaft 18 via the

gears

22 and 20. This results in a higher rotational speed and allows a higher maximum speed.

Description of the reference numerals

10 two speed transmission

12 input shaft

14 first gear stage

16 second gear stage

18 output shaft

20 first gear

22 first fixed gear

24 second gear

26 second fixed gear

28 sliding sleeve

30 first jaw

32 first opening

34 second jaw

36 second opening

38 actuating finger

40 operation actuator

42 first sliding ramp

44 second sliding ramp

46 lifting ramp

48 blocking element

50 spring element

52 spherical member

54 first blocking ramp

56 second blocking ramp

58 forward slope

60 backward slope

62 are open.

Claims

1. Two-speed transmission for electrically driven motor vehicles, in particular electric scooters, having a two-speed transmission

An input shaft (12) connectable to an electric machine for introducing torque,

an output shaft (18) connectable to a drive wheel for transferring the torque,

a first gear stage (14) for transmitting a rotational speed of the input shaft (12) to the output shaft (18) with a first gear ratio,

a second gear stage (16) for transmitting the rotational speed of the input shaft (12) to the output shaft (18) with a second gear ratio, different from the first gear ratio,

a sliding sleeve (28) which is guided on the input shaft (12) or on the output shaft (18) in a rotationally fixed but axially displaceable manner for producing a form-locking connection with a first gearwheel (20) of the first gear stage (14) and/or with a second gearwheel (24) of the second gear stage (16), and

an operating actuator (40) having extendable actuating fingers (38) for axially displacing the sliding sleeve (28),

wherein the sliding sleeve (28) has sliding ramps (42, 44) which extend in the circumferential direction and are angled relative to a radial plane for turning at the projecting actuating fingers (38) of the operating actuator (40), and

wherein the sliding ramp (42, 44) is axially resilient.

2. A two speed transmission as in claim 1, wherein the sliding sleeve (28) has: a first sliding ramp (42) extending in the circumferential direction and angled with respect to the radial plane for displacing the sliding sleeve (28) away from the first gear (20); and a second sliding ramp (44) extending in the circumferential direction and angled with respect to the radial plane for displacing the sliding sleeve (28) away from the second gear wheel (24), wherein the first sliding ramp (42) and the second sliding ramp (44) are arranged opposite each other in the axial direction to define a guide groove (62) formed in the sliding sleeve (28) for receiving a protruding actuation finger (38) of the operating actuator (40).

3. A two-speed transmission according to claim 1 or 2, characterized in that the sliding ramps (42, 44) are made of metal, preferably sheet metal or spring steel.

4. A two-speed transmission according to any of claims 1 to 3, characterized in that the sliding ramp (42, 44) is annular and provided with an opening, preferably of arcuate design.

5. A two-speed transmission as claimed in any one of claims 1 to 4, characterized in that said sliding ramp (42, 44) has: a forward ramp (58) for axially displacing the sliding sleeve (28) when the sliding sleeve (28) is rotated in a first circumferential direction relative to the actuation finger (38); and a rearward ramp (60) for axially displacing the sliding sleeve (28) when the sliding sleeve (28) is rotated relative to the actuating fingers (38) in a second circumferential direction opposite to the first circumferential direction, wherein in particular the forward ramp (58) and the rearward ramp (60) merge into one another at a circumferential angle of the sliding ramps (42, 44), wherein the projecting actuating fingers (38) have axially displaced the sliding sleeve (28) to a maximum extent.

6. A two-speed transmission according to any of claims 1 to 5, characterized in that the sliding ramps (42, 44) are arranged on the outside of the sliding sleeve (28).

7. A two speed transmission according to any of claims 1 to 6, wherein the sliding ramp (42, 44) is pressed onto the sliding sleeve (28).

8. A two-speed transmission as claimed in any preceding claim, wherein the following are provided: a first blocking ramp extending in the circumferential direction and angled in the axial direction for locking the sliding sleeve with the first gear; and/or a second blocking ramp extending in the circumferential direction and angled in the axial direction for locking the sliding sleeve with the second gear, wherein one blocking element is provided which engages with the first blocking ramp and/or the second blocking ramp in order to exert a blocking force on the component in the axial direction.

9. The two-speed transmission as claimed in claim 8, characterized in that the blocking element is designed as a rolling body, in particular a ball, which is prestressed by a spring element, wherein in particular the blocking element is received so as to be displaceable in the radial direction in the input shaft or the output shaft.

10. The two-speed transmission according to any of claims 1 to 9, characterized in that the axial displacement of the sliding sleeve between a first blocking position, in which the sliding sleeve is connected form-fittingly to the first gear wheel, and a second synchronizing position, in which the blocking element engages the first blocking ramp, in which the sliding sleeve is connected form-fittingly to the second gear wheel, and/or between a second blocking position, in which the blocking element engages the second blocking ramp, can be bridged by the axial displacement of the sliding sleeve when the actuating finger slides over the sliding ramp.