WO2021004578A1

WO2021004578A1 - Parking lock device for an electric drive axle and electric drive axle with a parking lock device

Info

Publication number: WO2021004578A1
Application number: PCT/DE2020/100561
Authority: WO
Inventors: Jochen Loeffelmann; Thomas HUEMMER; Peter WELKER; Florian Reinle; Sebastian Langhans
Original assignee: Schaeffler Technologies AG & Co. KG
Priority date: 2019-07-11
Filing date: 2020-06-29
Publication date: 2021-01-14
Also published as: DE102019118828B4; DE102019118828A1

Abstract

The invention relates to a parking lock device (1) for an electric drive axle of a motor vehicle, comprising a parking lock wheel (2), which is designed to be arranged coaxially on and for conjoint rotation with a shaft (3), which is connected to an electric machine (4) for conjoint rotation, and a locking pawl (5), which is designed to interact with a toothing (6) of the parking lock wheel (2) in order, in a locking position, to block rotation of the shaft (3) and, in a release position, to release rotation of the shaft (3), wherein the parking lock wheel (2) is in the shape of a pot consisting of a tubular portion (7) and a gearwheel portion (8) connected integrally thereto. Furthermore, the invention relates to an electric drive axle for a motor vehicle having such a parking lock device (1).

Description

Parking lock device for an electric drive axle and electric drive axle with a parking lock device

The invention relates to a parking lock device for an electric drive axle of a motor vehicle and an electric drive axle for a motor vehicle with egg ner parking lock device.

Parking lock devices are provided to intervene with a pawl in a toothing of a parking lock wheel of the motor vehicle transmission when actuated by a driver of the motor vehicle in order to block an output shaft of the transmission that is operatively connected to the parking lock wheel against rotation and thus prevent the motor vehicle from rolling away .

For example, DE 20 2009 014 189 U1 reveals an electrical machine design for an electrical axle of a motor vehicle. This comprises an electrical machine which is connected via a transmission to at least one drive shaft that can be connected to a driven wheel of the motor vehicle, and a machine housing. The electrical machine has a stator fixed to the housing and a rotor which is connected to an input element of the transmission. The rotor is rotatably mounted on the machine housing by means of a first and a second rotor bearing section, the first rotor bearing section being connected to a machine output shaft which is connected to the input member of the transmission. The machine output shaft is guided through the second rotor bearing section without contact. A parking lock arrangement, by means of which the transmission output shaft or the drive shaft is locked against the transmission housing, is received in a transmission housing of only one of the two machine arrangements. The parking lock arrangement has a parking lock wheel which is fixed to a plane carrier of the transmission.

The object of the present invention is to provide an improved parking lock device for an electric drive axle and an electric drive axle with such a parking lock device. In particular, torque damping should take place when the parking brake is applied. The task is solved by the subject matter of claim 1 and claim 7. Preferred embodiments can be found in the dependent claims.

A parking lock device according to the invention for an electric drive axle of a motor vehicle comprises a parking lock wheel, which is designed to be arranged coaxially and non-rotatably on a shaft that is non-rotatably connected to an electrical machine, and a pawl that is designed to be connected to a Ver Toothing of the parking lock gear cooperate in order to lock a rotation of the shaft in a locking pitch and release a rotation of the shaft in an unlocked position, the parking lock gear being pot-shaped from a pipe section and a gear section integrally connected therewith.

The invention also relates to an electric drive axle for a motor vehicle, to summarizing an electric machine which is connected to a transmission via a shaft, and a parking lock device with a parking lock gear and a pawl, the parking lock gear being arranged coaxially and non-rotatably on the shaft, with Furthermore, the pawl cooperates with a toothing of the parking lock gear to lock a rotation of the shaft in a locking pitch and release a rotation of the shaft in an unlocking position, and wherein the parking lock gear is formed from a tube section and an integral Zahnradab section.

In other words, the locking pawl is provided to engage in a tooth gap of the parking lock wheel in the locking pitch, a roller box preferably actuating the locking pawl between the locking pitch and the unlocking position. The roller box is switchable via an actuator or axially displaceable in the longitudinal direction of a guide rod. For example, with an axial displacement of the roller box in the longitudinal direction of the guide rod against a spring force of a spring element, an unlocking position of the pawl is initiated. The roller box slides along a ramp on a side of the pawl opposite to a pawl tooth that engages in a tooth gap on the parking lock gear, that the pawl tooth is removed from the tooth gap. According to the present example, when the roller box is axially displaced in the longitudinal direction of the guide rod and in the direction of the spring force of the spring element, a locking point ment of the pawl initiated. The roller box slides along the ramp on the side of the pawl opposite the pawl tooth in such a way that the pawl tooth engages in the tooth gap.

In particular, the parking lock gear is arranged positively on the shaft for the rotationally fixed connection, the parking lock gear and the shaft rotating about the same axis of rotation and thus being arranged coaxially to one another. The shaft is used to introduce a torque and a speed in the transmission of the electrical drive axis. The electrical machine is therefore operatively connected to the transmission via the shaft. The term “operatively connected” means that the shaft and the electrical machine or the shaft and the transmission can be directly connected to one another, or that there is between the shaft and the electrical machine or between the shaft and the transmission still further transmission elements, for example one or more shafts or gears, can be located. The electrical machine has a non-rotatable stator and a rotatable rotor which is at least indirectly connected to the shaft.

A pot-shaped parking lock gear is to be understood as a parking lock element which is essentially flange-shaped or pot-shaped and comprises the hollow cylindrical tube section and the gearwheel section formed in one piece thereon, which in turn has a central bore. Due to the cup-shaped design of the parking lock gear, torque damping is achieved when the parking lock device is actuated and the associated engagement of the pawl in a tooth gap on the parking lock gear. The geometry of the pot-shaped parking lock gear in the circumferential direction is softer and more flexible than the geometry of a conventional parking lock gear. In this way, a rotor shock in particular can be minimized, so that the electrical machine and the transmission are relieved when the parking lock is engaged. Furthermore, there is also an improved vibration damping when initiating the barrier division, which also leads to an acoustic optimization rule.

Preferably, the pipe section has on an inner circumferential surface a plug-in toothing which is designed to be connected non-rotatably to a plug-in toothing on an outer peripheral surface of the shaft. The spline therefore engages on the pipe section in the spline on the shaft to form a form-fitting and non-rotatable connection between the cup-shaped parking lock gear and the shaft.

The pipe section preferably has a bearing section on an outer circumferential surface which is designed to receive a first bearing element. Preferably, the first bearing element for the rotatable mounting of the shaft is arranged on the outer circumferential surface of the pipe section. The bearing element is preferably designed as a roller bearing, in particular as a ball bearing. The first bearing element is provided to absorb forces acting on the cup-shaped parking lock gear by actuating the parking lock device.

Preferably, an outer diameter of the parking lock gear is smaller than an outer diameter of the first bearing element. In particular, the outer diameter of an outer ring of the bearing element has a larger diameter than the root circle of the toothing on the gear section of the parking lock gear.

Furthermore, a second bearing element for the rotatable mounting of the shaft is preferably arranged at least indirectly on the shaft, the first bearing element being designed as a Losla ger. The second bearing element comes to rest either directly on the shaft or indirectly, for example via a further shaft or sleeve connected to the shaft. The formation of the first bearing element as a floating bearing simplifies the assembly of the entire parking lock device.

In particular, the gear section has several recesses. A recess is to be understood as a cutout or indentation or depression as a result of material removal. The recesses serve as a structural weakening of the parking lock gear and lead to the fact that the cup-shaped parking lock gear becomes softer and the torque damping is increased when the parking lock device is actuated

The recesses are preferably formed at the end face in the gear section, the recesses at least partially breaking axially through the gear section. In other words, the recesses are not just depressions formed, but as openings over the entire axial length of the gear wheel section.

Furthermore, each of the recesses is preferably formed in the circumferential direction between two tooth gaps. In particular, the recesses together with the central bore for the axial passage of the shaft form a star-shaped pattern. The respective recess extends radially below a respective tooth of the parking lock gear towards the center of the parking lock gear, i.e. in the direction of the axis of rotation.

Further measures improving the invention are shown in more detail below together with the description of a preferred exemplary embodiment of the invention with reference to the three figures. It shows

Figure 1 is a partially greatly simplified schematic sectional view for

Illustration of the structure of an electric drive axle according to the invention with a parking lock device according to the invention,

FIG. 2 shows a schematic perspective illustration of a parking lock wheel of the parking lock device according to the invention according to FIG. 1, and FIG

Figure 3 is a schematic sectional view of the parking lock gear according to the

Figures 1 and 2.

According to FIG. 1, an electric drive axle for a motor vehicle has an electric machine 4, a transmission 14 and a parking lock device 1. The electrical cal machine 4 and the transmission 14 are shown in the present greatly simplified. A shaft 16 designed as a hollow shaft is arranged between the electrical machine 4 and the gearbox 14 and connects the electrical machine 4 indirectly to the gearbox 14 via a further shaft 3 designed as a rotor shaft. The shaft 3, designed as a rotor shaft, is non-rotatably connected to a rotor of the electrical machine 4. The shaft 16 is preferably connected to a sun gear of the transmission 14 (not shown here). An output shaft - not shown here - of the transmission 14, which is at least indirectly connected to the wheels of the motor vehicle can be guided axially through the shaft 16 and the shaft 3 designed as a rotor shaft. The parking lock device 1 comprises a parking lock gear 2 and a locking pawl 5, the parking lock gear 2 being coaxially and non-rotatably arranged on the shaft 16 and rotating together with the shaft 16 about an axis of rotation 17. The locking pawl 5 cooperates with a toothing 6 of the parking lock gear 2 to lock a rotation of the shaft 16 in a locking pitch and to release rotation of the shaft 16 in an unlocked position. A rotation of the shaft 3 designed as a rotor shaft is therefore blocked at the same time in the blocking division. A roller box 18 is provided for actuating the pawl between the locking division and the Entsperrstel development.

The parking lock gear 2 is pot-shaped from a pipe section 7 and a gear section 8 connected to it in one piece. The pipe section 7 has on an inner circumferential surface a spline 9 which is non-rotatably connected to a spline 10 on an outer circumferential surface of the shaft 16. Furthermore, the pipe section 7 has a bearing section 11 on an outer circumferential surface which receives a first bearing element 12. The first bearing element 12 is arranged on the outer circumferential surface of the pipe section 7 for the rotatable mounting of the shaft 16. An outer diameter of the parking lock gear 2, i.e. the gear section 8, is smaller than an outer diameter of the first bearing element 12. Furthermore, a second bearing element 15 for the rotatable mounting of the shaft 16 is arranged on the shaft 16 indirectly via the shaft 3 designed as a Ro gate shaft. The first bearing element 12 is designed as a floating bearing.

In Figure 2, the pot-shaped parking lock gear 2, which is formed from the pipe section 7 and the one-piece connected gear section 8, is shown in perspective. The gear section 8 has a plurality of recesses 13, which are formed on the end face in the gear section 8 and extend in the radial direction towards the center. Furthermore, each of the recesses 13 is formed in the circumferential direction between two tooth gaps. The number of recesses 13 therefore corresponds to the number of teeth of the toothing 6 on the parking lock gear 2, and in the present case is six. The recesses 13 are at least partially formed as axial openings and break axially through the gear section 8. FIG. 3 shows the pot-shaped parking lock gear 2, which is formed from the pipe section 7 and the gear section 8 connected in one piece to it, according to a sectional view. In Figure 3, the spline 9 on the inner circumferential surface of the pipe section 7 and the toothing 6 on the outer circumference of the gear section 8 are shown.

Reference list

1 parking lock device

2 parking lock wheel

3 designed as a rotor shaft shaft

4 electric machine

5 pawl

6 teeth on the parking lock gear 7 pipe section

8 gear section

9 Splines on the parking lock gear

10 splines on the rotor shaft 1 1 bearing section

12 first bearing element

13 recess

14 transmission

15 second bearing element

16 wave

17 axis of rotation

18 roller box

Claims

1 . Parking lock device (1) for an electric drive axle of a motor vehicle, comprising a parking lock gear (2) which is designed to be arranged coaxially and non-rotatably on a shaft (16) which is connected to an electrical machine (4) in a non-rotatable manner , and a pawl (5) which is designed to cooperate with egg ner toothing (6) of the parking lock wheel (2) in order to block a rotation of the shaft (3) in a blocking position and a rotation of the shaft in an unlocked position (3) to release, wherein the parking lock gear (2) is pot-shaped from a pipe section (7) and a one-piece connected gear section (8) is formed.

2. Parking lock device (1) according to claim 1,

characterized in that the pipe section (7) has a plug-in toothing (9) on an inner circumferential surface which is designed to be non-rotatably connected to a plug-in toothing (10) on an outer circumferential surface of the shaft (3).

3. Parking lock device (1) according to one of the preceding claims, characterized in that the pipe section (7) has a bearing section (1 1) on an outer circumferential surface, which is designed to have a first bearing element

(12) included.

4. Parking lock device (1) according to any one of the preceding claims, characterized in that the gear section (8) has several recesses

(13).

5. parking lock device (1) according to claim 4,

characterized in that the recesses (13) are formed in the end face of the gear section (8), the recesses (13) at least partially penetrating axially through the gear section (8).

6. Parking lock device (1) according to one of claims 4 or 5, characterized in that each of the recesses (13) is formed in the circumferential direction between two tooth gaps.

7. Electric drive axle for a motor vehicle, comprising an electric machine (4) which is connected to a gear (14) via a shaft (3), and a parking lock device (1) with a parking lock wheel (2) and a pawl (5) , the parking lock gear (2) being arranged coaxially and non-rotatably on the shaft (3), the pawl (5) also cooperating with a toothing (6) of the parking lock gear (2) in order to allow the shaft (3) to rotate in a locking pitch to lock and release a rotation of the shaft (3) in an unlocked position, and wherein the parking lock gear (2) is pot-shaped from a tubular section (7) and a gear section (8) connected in one piece to it.

8. Electric drive axle according to claim 7,

characterized in that a first bearing element (12) for the rotatable mounting of the shaft (3) is arranged on an outer peripheral surface of the pipe section (7).

9. Electric drive axle according to claim 8,

characterized in that an outside diameter of the parking lock gear (2) is smaller than an outside diameter of the first bearing element (12).

10. Electric drive axle according to one of claims 8 or 9,

characterized in that a second bearing element (15) for the rotatable mounting of the shaft (3) is arranged at least indirectly on the shaft (3), the first bearing element (12) being designed as a floating bearing.