Park lock device for use with automatic transmission

• US 4,667,783 A
• Filed: 10/05/1984
• Issued: 05/26/1987
• Est. Priority Date: 10/14/1983
• Status: Expired due to Fees

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Hayasaki, Koichi, Sugano, Kazuhiko
• Primary Examiner(s): Herrmann, Allan D.
• Application Number:
  US06/658,212
• Time in Patent Office: 963 Days
• Field of Search: 188/69, 188/31, 188/265, 74/411.5, 74/577 S, 192/4 A
• US Class Current: 192/219.5
• CPC Class Codes: B60T 1/005 by locking of wheel or transmission rotation
• CPC Class Codes: F16H 63/3416 Parking lock mechanisms or brakes in the transmission
• CPC Class Codes: F16H 63/48 Signals to a parking brake or parking lock; Control of parking locks or brakes being part of the transmission
• CPC Class Codes: Y10T 74/19637 with brake means for gearing
• CPC Class Codes: Y10T 74/2137 Single tooth

Abstract

Herein disclosed is an improved arrangement of a park lock device for use with an automatic transmission, by which the transmission casing can be constructed simple and compact in size. The park lock device comprises a parking gear secured to the output shaft of the transmission to rotate therewith; a parking pawl pivotally connected to the casing to lock and unlock the parking gear, the pawl including first and second wing portions which extend in the opposed directions from the pivoted portion of the pawl, the first wing portion being formed with a tooth lockably engageable with a tooth gap of the parking gear; and an actuating mechanism having a cam member which is slidably engageable with the second wing portion to pivot the parking pawl in a direction to achieve the locking engagement between the tooth of the parking pawl and the tooth gap of the parking gear. The actuating mechanism is positioned essentially inboard of the parking pawl with respect to the transmission casing.

Claims

1. In an automatic transmission having an output shaft and a transmission casing, a park lock device comprising:

a parking gear coaxially and securedly mounted on said output shaft to rotate therewith;

a parking pawl having an axis pivotally connected to said casing for locking and unlocking said parking gear, said pawl including first and second wing portions which extend in opposing directions from the pivoted connection of the pawl, said first wing portion being formed with a tooth engageable with one of a plurality of tooth gaps of said parking gear;

an actuating mechanism, including;

a support shaft;

a cam member secured along an axial length of said support shaft and being slidably engageable with said second wing portion thereby to reversibly pivot said parking pawl in a direction to achieve locking engagement between the tooth of the pawl and the tooth gap of said parking gear, said actuating mechanism being positioned essentially inboard of said parking pawl with respect to the transmission casing;

wherein said first wing portion is arcuate and said second wing portion is shorter in length than said first wing portion, wherein said park lock device further includes positioning means for moving said support shaft in an axial direction and thereby positioning said cam member to achieve said reversible pivot of said parking pawl, said positioning means including a pivot plate secured at a first end to said supporting shaft and at a second end to a detent producing means, wherein said pivot plate pivots in a direction parallel to an inboard surface of said transmission casing.

2. An automatic transmission as claimed in claim 1, wherein said detent producing means includes:

a plurality of spaced recesses in said second end of said pivot plate;

a detent ball selectively engageable with said spaced recesses; and

a spring biasing said detent ball toward said pivot plate, said spring being received in a blind bore.

3. An automatic transmission as claimed in claim 1, wherein supporting shaft extends substantially parallel with the axis of said parking pawl.

4. An automatic transmission as claimed in claim 1, wherein the portion of said transmission casing adjacent said park lock device is flat.