# US 11,441,681 B2 · Method for activating a parking lock system and parking lock system

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- Number: US 11,441,681 B2
- Document ID: US11441681B2
- Status: Granted
- Kind: B2
- Application number: 17/050,473
- Filed: 2019-03-19
- Published: 2021-08-05
- Granted: 2022-09-13
- Earliest claimed: 2018-04-25
- Assignees: Robert Bosch GmbH
- Applicants: Robert Bosch GmbH
- Inventors: Frank Bast; Ingo Drewe
- Web page: https://patentgrep.com/patent/US11441681B2

## CPC

- F16H 63/48: Signals to a parking brake {or parking lock; Control of parking locks or brakes being part of the transmission}
- F16H 63/483: {Circuits for controlling engagement of parking locks or brakes}
- B60L 3/0076: {relating to braking}
- F16H 59/44: dependent on machine speed {, e.g. the vehicle speed} (F16H59/46 takes precedence)
- B60Y 2200/91: Electric vehicles
- F16H 2059/366: {Engine or motor speed}
- F16H 2059/446: {Detecting vehicle stop, i.e. the vehicle is at stand still, e.g. for engaging parking lock}
- F16H: GEARING
- B60L: PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES (arrangements or mounting of electrical propulsion units or of plural diverse prime-movers for mutual or common propulsion in vehicles B60K1/00, B60K6/20; arrangements or mounting of electrical gearing in vehicles B60K17/12, B60K17/14; preventing wheel slip by reducing power in rail vehicles B61C15/08; dynamo-electric machines H02K; control or regulation of electric motors H02P); SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES (electric coupling devices combined with mechanical couplings of vehicles B60D1/64; electric heating for vehicles B60H1/00); ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL (control or regulation of electric motors H02P); MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
- B60Y: INDEXING SCHEME RELATING TO ASPECTS CROSS-CUTTING VEHICLE TECHNOLOGY

## Abstract

Systems and methods related to activating a parking lock system in the drive train of a vehicle having at least one electrical machine comprising a transmission which is connected to driven wheels. The method includes comparing a rotational speed nE of the at least one electrical machine with the transmission to a predetermined threshold value for a limiting speed nG, triggering, in the event that the rotational speed nE is below the threshold value for the limiting speed nG, a command for the actuation of an actuator system for activating the parking lock system, triggering, in the event that the rotational speed nE exceeds the threshold value for the limiting speed nG, a command for preventing an actuation of an actuator system for activating the parking lock system, and miming through a second comparison stage so long as nE≥nG.

## Claims

### Claim 1

A method for activating a parking lock system (20) in a drive train (18) of a vehicle (10) with at least one electric motor (24), with a transmission, which is connected to driven wheels (16), the method comprising:
a) comparing a speed nE of the at least one electric motor (24) with the transmission with a preset limit speed nG which represents a threshold value,
b) when the speed nE falls below the limit speed nG, triggering a control command to actuate an actuating mechanism for activating the parking lock system (20),
c) when the speed nE exceeds the limit speed nG, preventing triggering of the control command to actuate the actuating mechanism for activating the parking lock system (20), and
d) performing a second comparison step (44) as long as nE>nG and, if nE<nG, branching to method step b)
wherein if the speed nEof the at least one electric motor (24) with the transmission exceeds the limit speed nG, the triggering of a control command for actuating the actuating mechanism for activating the parking lock system (20) is delayed by a period of time Δt.

### Claim 2 (depends on 1)

The method as claimed in claim 1, wherein there is a fixed correlation between the speed nE of the at least one electric motor (24) with the transmission and a speed vF of the vehicle (10).

### Claim 3 (depends on 1)

The method as claimed in claim 1, wherein the speed nE of the at least one electric motor (24) with the transmission is calculated in an evaluation unit (22) using the vehicle speed vF or a speed of the transmission.

### Claim 4 (depends on 1)

The method as claimed in claim 1, wherein the duration of the period of time Δt is dependent on a degree by which the limit speed nG is exceeded by the calculated speed nE of the at least one electric motor (24) with a transmission.

### Claim 5 (depends on 1)

The method as claimed in claim 1, wherein the control command is triggered to actuate the actuating mechanism for activating the parking lock system (20) in such a way that a front axle (12), a rear axle (14), or the drive train (18) is immobilized.

### Claim 6 (depends on 1)

The parking lock system (20) for a vehicle (10) with at least one electric motor (24), with a transmission, which is connected to the wheels (16) of the vehicle (10), wherein the parking lock system (20) is operated according to the method as claimed in claim 1, wherein the parking lock system (20) comprises a switchable positive-fit lock.

### Claim 7 (depends on 6)

The parking lock system (20) as claimed in claim 6, wherein the parking lock system (20) is associated with a front axle (12), a rear axle (14), or a drive train (18) of the vehicle (10).

### Claim 8 (depends on 6)

The parking lock system (20) as claimed in claim 6, wherein the parking lock system comprises a mechanical prohibiting mechanism which prevents the switchable positive-fit lock from engaging at a higher vehicle speed vF·s.