Engine variable camshaft timing phaser with planetary gear assembly

Patent metadata

Field	Value
Publication number	US-9810108-B2
Application number	US-201515507526-A
Country	US
Kind code	B2
Filing date	Aug 24, 2015
Priority date	Sep 4, 2014
Publication date	Nov 7, 2017
Grant date	Nov 7, 2017

Abstract

An engine variable camshaft timing phaser ( 10 ) includes a sprocket ( 12 ) and a planetary gear assembly ( 14 ). The sprocket ( 12 ) receives rotational drive input from an engine crankshaft. The planetary gear assembly ( 14 ) includes two or more ring gears ( 26, 28 ), multiple planet gears ( 24 ), a sun gear ( 22 ), and a wrap spring ( 76 ). One of the ring gears ( 26, 28 ) receives rotational drive input from the sprocket ( 12 ) and one of the ring gears ( 26, 28 ) transmits rotational drive output to an engine camshaft. The sun gear ( 22 ) engages with the planet gears ( 24 ). The wrap spring ( 76 ) experiences expansion and contraction exertions to permit advancing and retarding engine valve opening and closing, and to prevent advancing and retarding engine valve opening and closing.

First claim

What is claimed is:

1. An engine variable camshaft timing phaser ( 10 ), comprising:
a sprocket ( 12 ) receiving rotational drive input from an engine crankshaft;
a planetary gear assembly ( 14 ) comprising:
at least two ring gears ( 26 , 28 ), one of said at least two ring gears ( 26 , 28 ) receiving rotational drive input from said sprocket ( 12 ) and one of said at least two ring gears ( 26 , 28 ) transmitting rotational drive output to an engine camshaft;
a plurality of planet gears ( 24 ) engaged with said at least two ring gears ( 26 , 28 );
a sun gear ( 22 ) engaged with said plurality of planet gears ( 24 ); and
a wrap spring ( 76 ) having a pair of ends ( 82 , 84 ), said wrap spring ( 76 ) interrelated with said sun gear ( 22 ) for causing abutment with one of said pair of ends ( 82 , 84 ) and expansion or contraction exertions of said wrap spring ( 76 );

wherein, when said planetary gear assembly ( 14 ) is driven by an electric motor ( 32 ), abutment with one of said pair of ends ( 82 , 84 ) permits relative rotation between said sprocket ( 12 ) and the engine camshaft for advancing or retarding engine valve opening and closing, and when said planetary gear assembly ( 14 ) is back-driven by the engine camshaft, abutment with one of said pair of ends ( 82 , 84 ) prevents relative rotation between said sprocket ( 12 ) and the engine camshaft to preclude advancing or retarding engine valve opening and closing.

2. The engine variable camshaft timing phaser ( 10 ) as set forth in claim 1 , wherein expansion exertion of said wrap spring ( 76 ) prevents relative rotation between said sprocket ( 12 ) and the engine camshaft, and contraction exertion of said wrap spring ( 76 ) permits relative rotation between said sprocket ( 12 ) and the engine camshaft.

3. The engine variable camshaft timing phaser ( 10 ) as set forth in claim 1 , wherein said planetary gear assembly ( 14 ) further comprises a sleeve ( 78 ), said sleeve ( 78 ) and said sun gear ( 22 ) cooperating with each other via a projection-and-recess interfit, when said planetary gear assembly ( 14 ) is driven by the electric motor ( 32 ) said sleeve ( 78 ) is driven by the electric motor ( 32 ) and abutment between one of said pair of ends ( 82 , 84 ) and a wall ( 98 , 100 , 102 , 104 ) of said sleeve ( 78 ) permits relative rotation between said sprocket ( 12 ) and the engine camshaft, when said planetary gear assembly ( 14 ) is back-driven by the engine camshaft, abutment between one of said pair of ends ( 82 , 84 ) and a wall ( 48 , 50 , 52 , 54 ) of said sun gear ( 22 ) prevents relative rotation between said sprocket ( 12 ) and the engine camshaft.

4. The engine variable camshaft timing phaser ( 10 ) as set forth in claim 1 , wherein said planetary gear assembly ( 14 ) further comprises a sleeve ( 78 ), said sleeve ( 78 ) having a first wall ( 98 , 100 , 102 , 104 ) and a second wall ( 98 , 100 , 102 , 104 ), said sun gear ( 22 ) having a first wall ( 48 , 50 , 52 , 54 ) and a second wall ( 48 , 50 , 52 , 54 ), said first wall ( 98 , 100 , 102 , 104 ) of said sleeve ( 78 ) confronting said first wall ( 48 , 50 , 52 , 54 ) of said sun gear ( 22 ), said second wall ( 98 , 100 , 102 , 104 ) of said sleeve ( 78 ) confronting said second wall ( 48 , 50 , 52 , 54 ) of said sun gear ( 22 ), one of said pair of ends ( 82 , 84 ) situated between the confrontation of said first walls ( 48 , 50 , 52 , 54 , 98 , 100 , 102 , 104 ), and the other of said pair of ends ( 82 , 84 ) situated between the confrontation of said second walls ( 48 , 50 , 52 , 54 , 98 , 100 , 102 , 104 ).

5. The engine variable camshaft timing phaser ( 10 ) as set forth in claim 4 , wherein, when said planetary gear assembly ( 14 ) is driven by the electric motor ( 32 ), said sleeve ( 78 ) rotates and said first wall ( 98 , 100 , 102 , 104 ) of said sleeve ( 78 ) or said second wall ( 98 , 100 , 102 , 104 ) of said sleeve ( 78 ) comes into abutment with one of said pair of ends ( 82 , 84 ) and causes contraction exertion of said wrap spring ( 76 ) and permits relative rotation between said sprocket ( 12 ) and the engine camshaft.

6. The engine variable camshaft timing phaser ( 10 ) as set forth in claim 4 , wherein, when said planetary gear assembly ( 14 ) is back-driven by the engine camshaft, said first wall ( 48 , 50 , 52 , 54 ) of said sun gear ( 22 ) or said second wall ( 48 , 50 , 52 , 54 ) of said sun gear ( 22 ) comes into abutment with one of said pair of ends ( 82 , 84 ) and causes expansion exertion of said wrap spring ( 76 ) and prevents relative rotation between said sprocket ( 12 ) and the engine camshaft to preclude advancing or retarding engine valve opening and closing.

7. The engine variable camshaft timing phaser ( 10 ) as set forth in claim 1 , further comprising a lock ring ( 80 ) located at least partly around a periphery of said wrap spring ( 76 ), said lock ring ( 80 ) obstructing expansion of said wrap spring ( 76 ).

8. An engine variable camshaft timing phaser ( 10 ), comprising:
a sprocket ( 12 ) receiving rotational drive input from an engine crankshaft;
at least two ring gears ( 26 , 28 ), one of said at least two ring gears ( 26 , 28 ) receiving rotational drive input from said sprocket ( 12 ) and one of said at least two ring gears ( 26 , 28 ) transmitting rotational drive output to an engine camshaft;
a plurality of planet gears ( 24 ) engaged with said at least two ring gears ( 26 , 28 );
a sun gear ( 22 ) engaged with said plurality of planet gears ( 24 );
a sleeve ( 78 ) driven by an electric motor ( 32 );
a wrap spring ( 76 ) located at least partly around said sun gear ( 22 ) and at least partly around said sleeve ( 78 );
wherein, when said sleeve ( 78 ) is driven by the electric motor ( 32 ), said wrap spring ( 76 ) experiences contraction exertion and relative rotation between said sprocket ( 12 ) and the engine camshaft is permitted for advancing or retarding engine valve opening and closing, and when the engine camshaft back-drives the engine camshaft timing phaser ( 10 ), said wrap spring ( 76 ) experiences expansion exertion and relative rotation between said sprocket ( 12 ) and the engine camshaft is prevented to preclude advancing or retarding engine valve opening and closing.

9. The engine variable camshaft timing phaser ( 10 ) as set forth in claim 8 , wherein said wrap spring ( 76 ) has a pair of ends ( 82 , 84 ), said wrap spring ( 76 ) experiences contraction exertion via abutment between said sleeve ( 78 ) and one of said pair of ends ( 82 , 84 ), and said wrap spring ( 76 ) experiences expansion exertion via abutment between said sun gear ( 22 ) and one of said pair of ends ( 82 , 84 ).

10. The engine variable camshaft timing phaser ( 10 ) as set forth in claim 8 , wherein said sun gear ( 22 ) and said sleeve ( 78 ) cooperate with each other via a projection-and-recess interfit, said projection-and-recess interfit having a first set of confronting walls ( 48 , 50 , 52 , 54 , 98 , 100 , 102 , 104 ) between said sun gear ( 22 ) and said sleeve ( 78 ) and having a second set of confronting walls ( 48 , 50 , 52 , 54 , 98 , 100 , 102 , 104 ) between said sun gear ( 22 ) and said sleeve ( 78 ), said wrap spring ( 76 ) having a first end ( 82 ) situated between said first set of confronting walls ( 48 , 50 , 52 , 54 , 98 , 100 , 102 , 104 ) and having a second end ( 84 ) situated between said second set of confronting walls ( 48 , 50 , 52 , 54 , 98 , 100 , 102 , 104 ).

11. The engine variable camshaft timing phaser ( 10 ) as set forth in claim 10 , wherein said first set of confronting walls ( 48 , 50 , 52 , 54 , 98 , 100

Assignees

• Borgwarner Inc

Inventors

• Pritchard Larry A
• Benner Thomas R
• Pluta Christopher J

Classifications

• F01L2820/01

  Absolute values · CPC title

• F01L1/34403

  using helically teethed sleeve or gear moving axially between crankshaft and camshaft · CPC title

• F01L1/34409 Primary

  by torque-responsive means · CPC title

• F01L1/08

  Shape of cams · CPC title

• F01L1/3442

  using hydraulic chambers with variable volume to transmit the rotating force · CPC title