COMBINATION OF A GEARBOX AND A GEARBOX LOCKING DEVICE

Description

[0001] The present invention relates to a combination of a transmission and a device for blocking the transmission, for example for a vehicle transmission or a transmission for a door drive. State of the art

[0002] In automatic transmissions for motor vehicles, devices for locking the transmission are used as parking locks to prevent parked vehicles from rolling away accidentally. Typically, locking gears with tooth gaps are integrated into the drivetrain in a rotationally fixed manner. These locking gears block or release the rotation of the drive by means of actuatable pawls that positively engage the tooth gaps. These devices for locking the transmission, used as parking locks, are engaged when the selector lever of the automatic transmission is moved to the P position. This is necessary, for example, to release the vehicle key in the ignition lock for removal when the engine is not running.

[0003] WO 2009 / 074389 proposes a parking lock arrangement which blocks the transmission by means of a parking lock gear arranged in a rotationally fixed manner and coaxially to the drive shaft.

[0004] In electric motor vehicles, this device results in large torque shocks being exerted on the rotor of the electric drive motor when the parking lock is engaged due to the sudden braking of the drive shaft. These torque shocks exceed the torque shocks that occur during normal operation of the electric drive motor and can lead to damage to the electric drive motor and the transmission.

[0005] This effect does not occur in drives with combustion engines because the combustion engine is decoupled from the parking lock by the hydraulic torque converter.

[0006] In electrically powered vehicles, the rotor of the electric drive motor is constantly engaged with the transmission and is therefore not decoupled from the transmission when the parking lock is engaged.

[0007] There is therefore a need for a robust, functionally reliable, space-saving and cost-effective device for blocking gearboxes that avoids torque shocks.

[0008] DE 10 2015 214 339 A1 discloses a drive arrangement with an electric motor arranged in a housing and a transmission arranged in the housing. The transmission comprises an input stage connected to a rotor shaft of the electric motor, a load stage driven by the input stage, and a differential driven by the load stage. The input stage is implemented as a planetary gear, with a sun gear fixed to the rotor shaft, which is implemented as a hollow shaft, a planetary gear set mounted on a web stationary with respect to the housing, and a ring gear rotatably mounted on the web. The ring gear is mounted on the web via a connecting shaft via a main radial bearing, and a parking lock gear is connected in a rotationally fixed manner to the connecting shaft. The main radial bearing is arranged in a plane with the tooth crowns of the parking lock gear to prevent tilting of the parking lock gear.

[0009] US 2012 / 0216638 A1 describes a drive with an electric motor and a transmission that includes a parking lock gear. The parking lock gear is rotationally fixedly connected to an output shaft.

[0010] DE 10 2006 046 712 A1 discloses a transmission with a parking lock gear, wherein an external toothing of the parking lock gear is formed on a disk carrier disc, which is connected in a rotationally fixed manner to a drive shaft of the transmission.

[0011] DE 10 2009 021 300 A1 discloses a parking lock, wherein bolts can be inserted axially into holes in a spur gear by a mechanism. DE 10 2007 062 349 A1 discloses a transmission with a device for locking the transmission, which comprises a locking wheel with flexible spokes. Disclosure of the invention

[0012] The device according to the invention with the characterizing part of claim 1 has the advantage that a combination of a gear and a device for blocking the gear is created, which avoids torque shocks and is robust, functionally reliable, space-saving and cost-effective.

[0013] The invention relates to a combination of a transmission and a device for blocking the transmission with at least one shaft and at least one locking wheel arranged coaxially on the shaft, wherein the locking wheel arranged coaxially on the shaft is connected to the shaft of the transmission to be blocked by a rotationally flexible connection.According to the invention, the rotationally flexible connection between the locking gear and the shaft is a hollow shaft, wherein either the shaft is a drive shaft of the transmission and the locking gear with the rotationally flexible hollow shaft is arranged coaxially on the drive shaft of the transmission and the hollow shaft is connected in a rotationally fixed manner to a drive pinion of a first spur gear stage arranged on the drive shaft of the transmission, or the shaft is an intermediate shaft of the transmission and the locking gear with the rotationally flexible hollow shaft is arranged coaxially on the intermediate shaft of the transmission and the hollow shaft is connected in a rotationally fixed manner to a spur gear of a first spur gear stage of the transmission arranged on the intermediate shaft of the transmission.

[0014] The torsionally soft connection has the advantage that torque shocks occurring when the gear is locked are elastically cushioned by the torsionally soft connection, thus preventing damage to drive components caused by torque shocks exceeding those experienced during normal operation. Especially in the case of constantly engaged electric drives, the torsionally soft connection of the locking gear prevents damage to the electric drive motor.

[0015] For the gear locking device, a hollow shaft is advantageously used between the locking gear and a gear shaft. The geometric design of the hollow shaft, including diameter, length, and wall thickness, as well as the material selection, makes it very easy to determine the required mechanical properties of the hollow shaft.

[0016] Particularly advantageous in a first embodiment of the invention is the connection of the device for locking a gear through the rotationally fixed connection of the hollow shaft to a drive pinion of a first spur gear stage arranged on a drive shaft of the drive. The smallest torques act on the drive pinion, so the hollow shaft and the locking gear are advantageously designed only for these torques. Advantageously, the rotationally fixed connection with the drive pinion eliminates the need for an additional shaft-hub connection between the hollow shaft and the drive shaft.

[0017] In a second embodiment of the invention, the parking lock gear with the torsionally flexible hollow shaft is arranged coaxially on an intermediate shaft of the transmission. This arrangement enables the space-saving integration of the parking lock gear into the transmission and is very cost-effective, as any existing shaft with its bearings can be used.

[0018] A particularly advantageous feature is the connection of the gear locking device through the non-rotatable connection of the hollow shaft to a spur gear located on an intermediate shaft of the drive. The spur gear is continuously operatively connected to other spur gears of the gear, so the hollow shaft is also continuously operatively connected to the gear via this spur gear. Advantageously, the non-rotatable connection to the spur gear eliminates the need for an additional shaft-hub connection between the hollow shaft and the gear shaft.

[0019] The measures mentioned in the dependent claims enable advantageous further developments of the device specified in the independent claim.

[0020] The hollow shaft of the gear locking device is advantageously mounted on the drive shaft in a rotationally flexible manner. This bearing, designed as a plain bearing or roller bearing, advantageously prevents the locking forces of the locking gear from leading to bending stresses and thus to plastic deformation of the hollow shaft. This eliminates the risk of imbalance due to a deformed hollow shaft. The design of this bearing as a clearance fit is advantageous because the drive shaft and hollow shaft rotate at the same speed. Any deflection of the hollow shaft that may occur is supported by the clearance fit, with deflection of the hollow shaft causing the hollow shaft to come into contact with the drive shaft. The design of the clearance fit between the hollow shaft and drive shaft limits the greatest possible deflection of the hollow shaft in the elastic range.On the other hand, the clearance fit allows the hollow shaft to rotate when the gearbox lock is engaged, since no torque is transmitted. By using a clearance fit as a bearing, the hollow shaft can be easily pushed onto the drive shaft during assembly without any effort.

[0021] The hollow shaft of the gear locking device is advantageously mounted on the intermediate shaft in a rotationally flexible manner. This bearing, designed as a plain bearing or roller bearing, advantageously prevents the increased locking forces of the locking gear from leading to bending stresses and thus to plastic deformation of the hollow shaft when arranged on an intermediate shaft. This eliminates the risk of imbalance due to a deformed hollow shaft. The design of this bearing as a clearance fit is advantageous because the intermediate shaft and hollow shaft rotate at the same speed. Any deflection of the hollow shaft that may occur is supported by the clearance fit, with deflection of the hollow shaft causing the hollow shaft to come into contact with the intermediate shaft. The design of the clearance fit between the hollow shaft and intermediate shaft limits the greatest possible deflection of the hollow shaft in the elastic range.On the other hand, the clearance fit allows the hollow shaft to rotate when the gearbox lock is engaged, since no torque is transmitted. By using a clearance fit as a bearing, the hollow shaft can be easily pushed onto the intermediate shaft during assembly without any effort.

[0022] Further features and advantages of the present invention will become apparent to those skilled in the art from the following description of exemplary embodiments, which, however, are not to be construed as limiting the invention, with reference to the accompanying drawings. Short description of the drawings

[0023] They show: Fig. 1 : a schematic representation of a section through a drive with a combination according to the invention of a gear with a rotationally flexible device for blocking the gear with a locking wheel arranged on a hollow shaft; Fig. 2: a schematic sectional drawing through a drive with a combination according to the invention of a gear with a rotationally flexible device for blocking the gear with a locking wheel arranged on a hollow shaft; Fig. 3 : a schematic representation of an arrangement of a locking wheel in an electrically driven axle, not encompassed by the invention, adjacent to the rotor on the transmission side; Fig. 4 : a schematic representation of an arrangement of a locking wheel in an electrically driven axle, not encompassed by the invention, adjacent to the rotor on the rotor side; Fig. 5 : a schematic representation of a transmission-side flying arrangement of a locking wheel on the drive shaft in an electrically driven axle, not covered by the invention; Fig. 6: a schematic representation of a rotor-side flying arrangement of a locking wheel on the drive shaft in an electrically driven axle, not covered by the invention; Fig. 7 : a schematic representation of a flying arrangement, not covered by the invention, of a locking wheel on an intermediate shaft in an electrically driven axle; Fig. 8 : a schematic representation of an arrangement not covered by the invention of a locking gear on an intermediate shaft adjacent to a spur gear in an electrically driven axle; Fig. 9 : a schematic representation of an arrangement according to the invention of a locking gear connected to a spur gear via a hollow shaft on an intermediate shaft of an electrically driven axle; Fig. 10: a schematic representation of an arrangement not covered by the invention of a locking wheel on a separate shaft, non-rotatably connected to an intermediate shaft of a transmission of an electrically driven axle; Fig. 11 : a schematic representation of an arrangement not covered by the invention of a locking wheel on a separate shaft, connected on the transmission side in a rotationally fixed manner to the drive shaft of an electrically driven axle; Fig. 12 : a schematic representation of an arrangement not covered by the invention of a locking wheel on a separate shaft, connected on the rotor side in a rotationally fixed manner to the drive shaft of an electrically driven axle, Fig. 13 : a schematic representation of an arrangement not covered by the invention of a locking wheel on a separate shaft, non-rotatably connected to a spur gear engaging in the transmission.

[0024] In particular, distances and size relationships are not shown to scale in the figures. Corresponding elements in the different figures are provided with the same reference numbers.

[0025] Figure 1shows a schematic representation of a section through a drive unit 14 consisting of an electric motor 17 and a gearbox 2. The electric motor 17 is shown with its rotor 15 and the drive shaft 5. The electric motor 17 drives the operatively connected spur gear 8 of a spur gear stage 9 via the drive pinion 6 arranged on its drive shaft 5. The output 21 of the spur gear stage 9 drives the operatively connected differential gear 18. In multi-track vehicles, the different running paths of the inside and outside wheels are compensated for via the differential gear 18. The hollow shaft 11, which is arranged coaxially to the drive shaft 5, is rotationally fixedly connected to the drive pinion 6, via which hollow shaft 11 the locking gear 3 is rotationally smoothly connected to the drive pinion 6. The gear 2 is blocked when necessary via the pawl with locking element 19.The drive shaft 5 is supported by the rolling bearings 22, 23 and 24, wherein at least one of the rolling bearings 22, 23 and 24 is designed as a fixed bearing to absorb the longitudinal forces of the drive shaft 5.

[0026] Figure 2shows a schematic sectional drawing through a drive unit 14 of an electric axle drive. This drive unit 14 consists of an electric motor 17 and a gearbox 2. The electric motor 17 is shown with its stator 25 and its rotor 15 and the drive shaft 5. The drive pinion 6 is arranged on the drive shaft 5 with a rotationally fixed connection. A tongue and groove connection, a splined shaft connection or another suitable positive shaft-hub connection can be used for this purpose. The drive pinion 6 drives the input spur gear 8 of the intermediate stage 9, which is arranged on an intermediate shaft 10 and operatively connected to the drive pinion 6. The input spur gear 8 is rotationally fixedly connected to the intermediate shaft 10 of the intermediate stage 9 via a tongue and groove connection or a splined shaft connection or another suitable positive shaft-hub connection.The output spur gear 21 of the intermediate stage 9 is also arranged on the intermediate shaft 10 in a rotationally fixed manner. A tongue and groove connection, a splined connection, or another suitable positive shaft-hub connection can be used for this purpose. Instead of positive connections, material-to-material connections can also be selected. For example, the intermediate shaft 10 with the input spur gear 8 and the output spur gear 21 can be manufactured from a single blank. Likewise, a part consisting of the intermediate shaft 10 with the input spur gear 8 and the output spur gear 21 can be produced by welding two or more blanks. The output spur gear 21 drives the operatively connected differential gear 18. The hollow shaft 11, which is arranged coaxially to the drive shaft 5, is rotationally fixedly connected to the drive pinion 6, via which the locking gear 3 is rotationally connected to the drive pinion 6.The gear 2 is blocked when necessary via the pawl with locking element 19. The drive shaft 5 is supported by roller bearings 22, 23 and 24, with at least one of the roller bearings 22, 23 and 24 being designed as a so-called fixed bearing to absorb the longitudinal forces of the drive shaft 5. The bearing point 26 is provided for the torsionally soft mounting of the hollow shaft 11 and the locking gear 3 on the drive shaft 5. This bearing point 26 advantageously prevents the locking forces of the locking gear 3 from leading to undue deformation of the hollow shaft 11 via bending stresses. This eliminates the possibility of an imbalance due to a defectively deformed hollow shaft 11. The design of this bearing point 26 as a clearance fit is advantageous because the drive shaft 5 and the hollow shaft 11 rotate at the same speed.Any elastic deflection of the hollow shaft 11 that may occur is supported by the clearance fit, whereby a deflection of the hollow shaft 11 leads to the hollow shaft 11 coming into contact with the drive shaft 5. The design of the clearance fit between the hollow shaft 11 and the drive shaft 5 limits the greatest possible deflection of the hollow shaft 11. On the other hand, the clearance fit allows rotation of the hollow shaft 11 when engaging the pawl with the locking element 19 of the gearbox, since no torque is transmitted via the bearing point 26. By using a clearance fit as the bearing point 26, the hollow shaft 11 can be easily pushed onto the drive shaft 5 during assembly without any effort.

[0027] Figure 3shows a schematic representation of an arrangement of a locking wheel 3 on the drive shaft 5 in a drive unit of an electrically driven axle 14, adjacent to the rotor 15 on the gearbox side. In this particularly space-saving design, the use of a locking wheel 3 with elastic spokes is recommended for the smooth locking of the gearbox 2. The entire drive unit consists of an electric motor 17 and a gearbox 2. The electric motor 17 is shown with its stator 25 and its rotor 15 and the drive shaft 5. The drive pinion 6 is arranged on the drive shaft 5 with a rotationally fixed connection. The drive shaft is mounted via the rolling bearings 22, 23 and 24. The gearbox 2 is shown as a two-stage spur gear transmission. The drive pinion 6 is operatively connected to the input spur gear 8.The input spur gear 8, which is arranged in a rotationally fixed manner on the intermediate shaft 10, drives the output spur gear 21, which is arranged in a rotationally fixed manner on the intermediate shaft 10, via the intermediate shaft 10. This output spur gear 21 is operatively connected to the differential gear 18.

[0028] Figure 4 shows a schematic representation of an arrangement of a locking wheel 3 on the drive shaft 5 of a drive unit of an electrically driven axle 14, adjacent to the rotor 15 on the rotor side. In this particularly space-saving design, as in Figure 3 also proposes the use of a locking wheel 3 with elastic spokes for the torsionally smooth locking of the gear 2. With this arrangement, the locking wheel 3, together with the pawl 19 and the locking element, can be integrated into the electric motor 17. In addition to being used in integrated drive units 14, this arrangement is also suitable for use in drives with a separate electric motor 17 and gear 2.

[0029] Figure 5 shows a schematic representation of a transmission-side flying arrangement of a locking wheel 3 on the drive shaft 5 of a drive unit of an electrically driven axle 14. In this embodiment, as in the Figure 3 and 4 also proposes the use of a locking wheel 3 with elastic spokes for the torsionally smooth blocking of the gear 2. With this arrangement, the locking wheel 3 can be integrated into the gear 2 together with the pawl 19 and the locking element. In addition to being used in integrated drive units 14, this arrangement is also suitable for use in drives with a separate electric motor 17 and gear 2.

[0030] Figure 6 shows a schematic representation of a rotor-side flying arrangement of a locking wheel 3 on the drive shaft 5 of a drive unit of an electrically driven axle 14. In this embodiment, as in the Figure 3 ,4 and 5 also proposes the use of a locking wheel 3 with elastic spokes for the torsionally smooth locking of the gear 2. With this arrangement, the locking wheel 3 can be mounted together with the pawl 19 and the locking element on the electric motor 17. In addition to being used in integrated drive units 14, this arrangement is also suitable for use in drives with a separate electric motor 17 and gear 2.

[0031] Figure 7shows a schematic representation of a floating arrangement of a locking wheel 3 on an intermediate shaft 10 of a drive unit of an electrically driven axle 14. In this embodiment, the use of a locking wheel 3 with elastic spokes is recommended for the torsionally smooth blocking of the transmission 2. The hub of the locking wheel 3, the input spur gear 8, and the output spur gear 21 are connected in a rotationally fixed manner to the intermediate shaft 10. With this arrangement, the locking wheel 3 can be attached to the transmission 2 together with the pawl 19 with the locking element. In addition to being used in integrated drive units 14, this arrangement is also suitable for use in drives with a separate electric motor 17 and transmission 2.

[0032] Figure 8shows a schematic representation of an integrated arrangement of a locking wheel 3 on an intermediate shaft 10 of a drive unit of an electrically driven axle 14. In this embodiment, the use of a locking wheel 3 with elastic spokes is recommended for the torsionally smooth blocking of the transmission 2. The hub of the locking wheel 3, the input spur gear 8, and the output spur gear 21 are connected in a rotationally fixed manner to the intermediate shaft 10. With this arrangement, the locking wheel 3 can be integrated into the transmission 2 together with the pawl 19 and the locking element. In addition to being used in integrated drive units 14, this arrangement is also suitable for use in drives with a separate electric motor 17 and transmission 2.

[0033] Figure 9shows a schematic representation of an integrated arrangement of a locking gear 3 with a hollow shaft 11 on an intermediate shaft 10 of a drive unit of an electrically driven axle 14. The hollow shaft 11 for the smooth locking of the transmission 2 is non-rotatably connected to the output spur gear 21, which in turn is non-rotatably connected to the intermediate shaft 10. The input spur gear 8 is also non-rotatably connected to the intermediate shaft 10. With this arrangement, the locking gear 3 can be integrated into the transmission 2 together with the pawl 19 and the locking element. In addition to being used in integrated drive units 14, this arrangement is also suitable for use in drives with a separate electric motor 17 and transmission 2.

[0034] Figure 10shows a schematic representation of a non-rotatable arrangement of a locking wheel 3 on its own shaft, which is non-rotatably connected to an intermediate shaft 10 of a transmission 2 of a drive unit of an electrically driven axle 14. The non-rotatable coupling 27 connects a stub of the intermediate shaft 10 to a bearing shaft 28 on which the locking wheel 3 is arranged. With this arrangement, the locking wheel 3 can be attached to the transmission 2 together with the pawl 19 with the locking element. In this design, the use of a locking wheel 3 with elastic spokes is recommended for the smooth, torsionally locking of the transmission 2.

[0035] Figure 11shows a schematic representation of a non-rotatable arrangement of a locking wheel 3 on its own shaft, which is non-rotatably connected on the gearbox 2 side to the drive shaft 5 of a drive unit of an electrically driven axle 14. The non-rotatable coupling 27 connects a gearbox-side stub of the drive shaft 5 to a bearing shaft 28 on which the locking wheel 3 is arranged. With this arrangement, the locking wheel 3 can be attached to the gearbox 2 together with the pawl 19 with the locking element. In this design, the use of a locking wheel 3 with elastic spokes is recommended for the smooth, torsion-free locking of the gearbox 2.

[0036] Figure 12shows a schematic representation of a non-rotatable arrangement of a locking wheel 3 on its own shaft, which is non-rotatably connected on the electric motor 17 side to the drive shaft 5 of a drive unit of an electrically driven axle 14. The non-rotatable coupling 27 connects a rotor-side stub of the drive shaft 5 to a bearing shaft 28 on which the locking wheel 3 is arranged. With this arrangement, the locking wheel 3 can be attached to the electric motor 17 together with the pawl 19 with the locking element. In this design, the use of a locking wheel 3 with elastic spokes is recommended for the smooth, torsion-free blocking of the transmission 2.

[0037] Figure 13shows a schematic representation of a locking wheel 3 on its own bearing shaft 28, which is rotationally fixedly connected to a locking spur gear 29. This locking spur gear 29 is operatively connected to the drive pinion 6. In this embodiment, the locking wheel 3, together with the bearing shaft 28 and the pawl (not shown) with locking element 19, forms a unit. This unit can be mounted as a separate unit in a gearbox 2. In this embodiment, the use of a locking wheel 3 with elastic spokes is recommended for the smooth locking of the gearbox 2. The hub of the locking wheel 3 with elastic spokes is rotationally fixedly connected to the locking spur gear 29, thus ensuring smooth locking of the gearbox 2.

Claims

1. Combination of a transmission (2) and a device for blocking the transmission (2) with at least one shaft and at least one locking wheel (3) coaxially arranged on the shaft, wherein the locking wheel (3) coaxially arranged on the shaft is connected by a rotationally flexible connection (4) to the shaft of the transmission to be blocked (2), characterized in that the rotationally flexible connection (4) between the locking wheel (3) and shaft is a hollow shaft (11), wherein either - the shaft is a drive shaft (5) of the transmission (2), and the locking wheel (3) is coaxially arranged by the rotationally flexible hollow shaft (11) on the drive shaft (5) of the transmission (2) and the hollow shaft (11) is rotationally fixedly connected to a drive pinion (6) of a first spur gear stage (9), the drive pinion being arranged on the drive shaft (5) of the transmission (2), or - the shaft is an intermediate shaft (10) of the transmission (2) and the locking wheel (2) is coaxially arranged by the rotationally flexible hollow shaft (11) on the intermediate shaft (10) of the transmission (2) and the hollow shaft (11) is rotationally fixedly connected to a spur gear (8) of a first spur gear stage (9) of the transmission (2), the spur gear being arranged on the intermediate shaft (10) of the transmission (2).

2. Combination according to Claim 1, characterized in that the shaft of the transmission (2) is the drive shaft (5) of the transmission (2) and the hollow shaft (11) is rotationally flexibly mounted on the drive shaft (5).

3. Combination according to Claim 1, characterized in that the shaft of the transmission (2) is the intermediate shaft (10) of the transmission (2) and the hollow shaft (11) is rotationally flexibly mounted on the intermediate shaft (10).