Park Lock System with Added Safety Features

Patent metadata

Field	Value
Publication number	US-2021197771-A1
Application number	US-201916731647-A
Country	US
Kind code	A1
Filing date	Dec 31, 2019
Priority date	Dec 31, 2019
Publication date	Jul 1, 2021
Grant date	—

Abstract

A park lock system for a vehicle transmission, includes a movable primary carrier, a secondary carrier, a rod, a first biasing member, an engagement carrier, and a first actuator. The movable primary carrier defines a primary internal space. The secondary carrier is located within the primary internal space and is movable relative to the primary carrier. The rod fixedly extends from the secondary carrier and includes a rod portion located outside of the primary internal space. The first biasing member is located within the primary internal space between the secondary carrier and the primary carrier. The engagement carrier is configured to receive the rod portion and includes a terminal portion operably connected to a pawl and a park lock wheel arrangement to lock and unlock the vehicle transmission. The first actuator is configurable in a first state or a second state.

First claim

What is claimed is:

1 . A park lock system for a vehicle transmission, comprising:
a movable primary carrier defining a primary internal space; a secondary carrier located within the primary internal space and movable relative to the primary carrier; a rod fixedly extending from the secondary carrier and including a rod portion located outside of the primary internal space; a first biasing member located within the primary internal space between the secondary carrier and the primary carrier; an engagement carrier configured to receive the rod portion and including a terminal portion operably connected to a pawl and a park lock wheel to lock and to unlock the vehicle transmission; a first actuator configurable in a first state or a second state, wherein in the first state of the first actuator (i) the first actuator prevents movement of the secondary carrier relative to the primary carrier, (ii) movement of the primary carrier to a park position locks the vehicle transmission, and (iii) movement of the primary carrier to a drive position unlocks the vehicle transmission, and wherein in the second state of the first actuator (i) the secondary carrier is movable relative to the primary carrier, and (ii) the vehicle transmission is locked independent of the position of the primary carrier.

2 . The park lock system as claimed in claim 1 , wherein:
the first actuator includes a pin operably connected to a solenoid, in the first state of the first actuator, the pin extends through an opening in the primary carrier and is positioned in a detent of the secondary carrier, in the second state of the first actuator, the pin is removed from the detent, the first state is a de-energized state, and the second state is an energized state.

3 . The park lock system as claimed in claim 1 , further comprising:
a second actuator configured to move the primary carrier to the park position and the drive position.

4 . The park lock system as claimed in claim 3 , further comprising:
a rack mounted on the primary carrier, wherein the second actuator includes a pinon operably connected to the rack.

5 . The park lock system as claimed in claim 1 , wherein when the first actuator is in the second state, the first biasing member biases the secondary carrier and the pin away from the pawl.

6 . The park lock system as claimed in claim 5 , wherein:
the primary carrier defines an engagement opening through which the rod extends, and when the first actuator is in the second state, the biasing member biases a portion of the engagement carrier into the primary internal space through the engagement opening.

7 . The park lock system as claimed in claim 5 , further comprising:
a second biasing member located within the engagement internal space and configured to bias the engagement carrier toward the secondary carrier.

8 . A method of operating a park lock system for a vehicle having a primary supply voltage operably connected to the park lock system, a secondary supply voltage operably connected to the park lock system, and a traction motor, the method comprising:
configuring the park lock system to unlock a transmission of the vehicle; detecting that the primary supply voltage is available or unavailable with a control unit of the park lock system; detecting that the secondary supply voltage is available or unavailable with the control unit; configuring the park lock system to lock the transmission of the vehicle when the primary supply voltage and the secondary supply voltage are both unavailable with the control unit; when the primary supply voltage is unavailable and the secondary supply voltage is available
monitoring a wheel speed of a wheel of the vehicle with a wheel speed sensor operably connected to the control unit,
detecting if wheel locking of the wheel is occurring with the wheel speed sensor, and
configuring the park lock system to lock the transmission when the monitored wheel speed is less than a predetermined speed value and no wheel locking is detected.

9 . The method as claimed in claim 8 , further comprising:
when the primary supply voltage is unavailable and the secondary supply voltage is available, preventing the park lock system from locking the transmission when the detected wheel speed is greater than or equal to the predetermined speed value.

10 . The method as claimed in claim 8 , further comprising:
when the primary supply voltage is unavailable and the secondary supply voltage is available, preventing the park lock system from locking the transmission when the detected wheel speed is less than the predetermined speed value and wheel locking is detected.

11 . The method as claimed in claim 8 , further comprising:
when the primary supply voltage is unavailable, the secondary supply voltage is available, and wheel locking is detected implementing a delay prior to locking the transmission.

12 . The method as claimed in claim 8 , further comprising:
detecting that the primary supply voltage is available when a voltage value of the primary supply voltage is greater than or equal to a predetermined voltage value; and detecting that the primary supply voltage is unavailable when the voltage value of the primary supply voltage is less than the predetermined voltage value.

13 . The method as claimed in claim 12 , further comprising:
detecting that the secondary supply voltage is available when a voltage value of the secondary supply voltage is greater than or equal to another predetermined voltage value; and detecting that the secondary supply voltage is unavailable when the voltage value of the secondary supply voltage is less than the other predetermined voltage value.

14 . A park lock system for a vehicle transmission, comprising;
a pawl movable to a locked position relative to a park lock wheel and biased toward an unlocked position relative to the park lock wheel; a rod operably connected to the pawl and movable to an engaged position and a disengaged position, in the engaged position the pawl is pressed toward the locked position to lock the transmission, and in the disengaged position the pawl is biased to the unlocked position to unlock the transmission; a primary carrier operably connected to the rod and movable to a park position and a drive position; a biasing member located within the primary carrier; and an actuator operably connected to the rod and configurable in a first state and a second state, wherein when the actuator is in the first state (i) movement of the primary carrier to the park position moves the rod to the engaged position, and (ii) movement of the primary carrier to the drive position moves the rod to the disengaged position, and wherein when the actuator is in the second state the biasing member moves the rod to the disengaged position independent of a position of the primary carrier.

15 . The park lock system as claimed in claim 14 , further comprising:
a secondary carrier located within the primary carrier, wherein the rod fixedly extends from the secondary carrier.

16 . The park lock system as claimed in claim 15 , wherein:
the actuator includes a pin operably connected to a solenoid, wherein in the first state of the actuator, the pin extends through an opening in the primary carrier and is positioned in a detent of the secondary carrier to prevent movement of the secondary carrier relative to the primary carrier, and wherein in the second state of the actuator, the pin is removed from the detent and the biasing member moves the secondary carrier relative to the primary carri

Assignees

• Bosch Gmbh Robert

Inventors

• Frister Frank
• Belley Martin
• Hahn Axel

Classifications

• F16H2200/0021

  specially adapted for electric vehicles · CPC title

• F16H63/3466

  using electric motors · CPC title

• F16H63/3475

  using solenoids · CPC title

• F16H2061/1292

  the failing part is the power supply, e.g. the electric power supply · CPC title

• F16H61/12

  Detecting malfunction or potential malfunction, e.g. fail safe (in control of hydrostatic gearing F16H61/4192) {; Circumventing or fixing failures} · CPC title