Electric motor driven simple planetary cam phaser

Patent metadata

Field	Value
Publication number	US-9551244-B2
Application number	US-201314648098-A
Country	US
Kind code	B2
Filing date	Nov 22, 2013
Priority date	Dec 10, 2012
Publication date	Jan 24, 2017
Grant date	Jan 24, 2017

Abstract

A cam phaser ( 10 ) dynamically adjusts a rotational relationship of a camshaft ( 24 ) of an internal combustion engine with respect to an engine crankshaft ( 34 ). A cam sprocket ( 20 ) can be driven by an endless loop power transmission member connected to a drive sprocket ( 36 ) mounted for rotation with the engine 5 crankshaft ( 34 ). The cam phaser ( 10 ) can include a planetary gear drive train ( 12 ) having a centrally located sun gear ( 14 ) connected for rotation with the cam sprocket ( 20 ), a ring gear ( 18 ) connected for rotation with the camshaft ( 24 ), and a plurality of planet gears ( 16 a, 16 b ) supported by a carrier ( 22 ) in meshing engagement between the sun gear ( 14 ) and the ring gear ( 18 ). A phase adjustment gear ( 26 ) can be 10 connected for rotation with the carrier ( 22 ). The sun gear ( 14 ) can drive the planet gears ( 16 a, 16 b ) in rotation thereby causing the ring gear ( 18 ) to be driven in rotation. Rotational movement the phase adjustment gear ( 26 ) can adjustably vary a cam phase position of the camshaft ( 24 ) relative to the crankshaft ( 34 ).

First claim

What is claimed is:

1. In a cam phaser ( 10 ) for dynamically adjusting a rotational relationship of a camshaft ( 24 ) of an internal combustion engine with respect to an engine crankshaft ( 34 ), a cam sprocket ( 20 ) driven by an endless loop power transmission member ( 38 ) connected to a drive sprocket ( 36 ) mounted for rotation with the engine crankshaft ( 34 ), an improvement of the cam phaser comprising:
a planetary gear system ( 12 ) having a centrally located sun gear ( 14 ) connected for rotation with the cam sprocket ( 20 ), a ring gear ( 18 ) connected for rotation with the camshaft ( 24 ), and a plurality of planet gears ( 16 a , 16 b ) supported by a carrier ( 22 ) in meshing engagement between the sun gear ( 14 ) and the ring gear ( 18 ); and
a phase adjustment gear ( 26 ) connected for rotation with the carrier ( 22 ), wherein the sun gear ( 14 ) drives the planet gears ( 16 a , 16 b ) in rotation thereby causing the ring gear ( 18 ) to be driven in rotation, and rotational movement of the phase adjustment gear ( 26 ) adjustably varies a cam phase position of the camshaft ( 24 ) relative to the crankshaft ( 34 ).

2. The improvement of the cam phaser of claim 1 further comprising:
the drive sprocket ( 36 ) to cam sprocket ( 20 ) drive ratio being less than 1:1; and
a planetary gear ratio of sun gear ( 14 ) to ring gear ( 18 ) with the carrier ( 22 ) held stationary being greater than 0.5:1, such that a product of the drive sprocket ( 36 ) to cam sprocket ( 20 ) drive ratio with the planetary gear ratio equals an overall combined drive ratio of 0.5:1.

3. The improvement of the cam phaser of claim 1 further comprising:
an electric motor ( 28 ) connected for rotating the phase adjustment gear ( 26 ), wherein the electric motor ( 28 ) drives the phase adjustment gear ( 26 ) in rotational movement, thereby changing an angular position of the carrier ( 22 ) resulting in a cam phase position change of the camshaft ( 24 ) relative to the crankshaft ( 34 ).

4. The improvement of the cam phaser of claim 3 further comprising:
a sensor ( 30 ) providing feedback to a controller ( 32 ) of the electric motor ( 28 ) to measure a current position of the cam sprocket ( 20 ) relative to the camshaft ( 24 ) to determine if a cam phase position adjustment is required.

5. The improvement of the cam phaser of claim 1 , wherein the phase adjustment gear ( 26 ) is a worm gear.

6. The improvement of the cam phaser of claim 1 , wherein the sun gear ( 14 ), the ring gear ( 18 ), and the plurality of planet gears ( 16 a , 16 b ) have helical gear teeth.

7. A cam phaser ( 10 ) for dynamically adjusting a rotational relationship of a camshaft ( 24 ) of an internal combustion engine with respect to an engine crankshaft ( 34 ), a cam sprocket ( 20 ) driven by an endless loop power transmission member ( 38 ) connected to a drive sprocket ( 36 ) mounted for rotation with the engine crankshaft ( 34 ), the cam phaser ( 10 ) comprising:
a planetary gear drive train ( 12 ) having a centrally located sun gear ( 14 ) connectable for rotation with the cam sprocket ( 20 ), a ring gear ( 18 ) connectable for rotation with the camshaft ( 24 ), and a plurality of planet gears ( 16 a , 16 b ) supported by a carrier ( 22 ) in meshing engagement between the sun gear ( 14 ) and the ring gear ( 18 ); and
a phase adjustment gear ( 26 ) connected for rotation with the carrier ( 22 ), wherein the sun gear ( 14 ) drives the planet gears ( 16 a , 16 b ) in rotation thereby causing the ring gear ( 18 ) to be driven in rotation, and rotational movement the phase adjustment gear ( 26 ) adjustably varies a cam phase position of the camshaft ( 24 ) relative to the crankshaft ( 34 ).

8. The cam phaser of claim 7 further comprising:
the cam sprocket ( 20 ) mounted for rotation with respect to a camshaft axis and drivably connected with the drive sprocket ( 36 ) to be driven thereby at a first drive ratio less than 1:1; and
the planetary gear drive train ( 12 ) drivably connected between the cam sprocket ( 20 ) and the camshaft ( 24 ) for driving the camshaft ( 24 ) at a second drive ratio greater than 0.5:1, such that a product of the first drive ratio and the second drive ratio equals a combined drive ratio of 0.5:1.

9. The cam phaser of claim 7 further comprising:
an electric motor ( 28 ) connected to the phase adjustment gear ( 26 ), wherein the electric motor ( 28 ) rotates the phase adjustment gear ( 26 ), thereby changing an angular position of the carrier ( 22 ) resulting in a cam phase position change of the camshaft ( 24 ) relative to the crankshaft ( 34 ).

10. The cam phaser of claim 9 further comprising:
a sensor ( 30 ) providing feedback to a controller ( 32 ) of the electric motor ( 28 ) to measure a current position of the cam sprocket ( 20 ) relative to the camshaft ( 24 ) to determine if a cam phase position adjustment is required.

11. The cam phaser of claim 7 , wherein the phase adjustment gear ( 26 ) is a worm gear.

12. The cam phaser of claim 7 , wherein the sun gear ( 14 ), the ring gear ( 18 ), and the plurality of planet gears ( 16 a , 16 b ) have helical gear teeth.

13. A method for assembling and for dynamically adjusting a rotational relationship of a camshaft ( 24 ) of an internal combustion engine with respect to an engine crankshaft ( 34 ) , a cam sprocket ( 20 ) driven by an endless loop power transmission member ( 38 ) connected to a drive sprocket ( 36 ) mounted for rotation with the engine crankshaft ( 34 ), the method comprising:
assembling a planetary gear drive train ( 12 ) having a centrally located sun gear ( 14 ) connectable for rotation with the cam sprocket ( 20 ), a ring gear ( 18 ) connectable for rotation with the camshaft ( 24 ), and a plurality of planet gears ( 16 a , 16 b ) supported by a carrier ( 22 ) in meshing engagement between the sun gear ( 14 ) and the ring gear ( 18 ); and
connecting a phase adjustment gear ( 26 ) for rotation with the carrier ( 22 ), wherein the sun gear ( 14 ) drives the planet gears ( 16 a , 16 b ) in rotation thereby causing the ring gear ( 18 ) to be driven in rotation, and rotational movement of the phase adjustment gear ( 26 ) adjustably varies a cam phase position of the camshaft ( 24 ) relative to the crankshaft ( 34 ).

14. The method of claim 13 further comprising:
connecting an electric motor ( 28 ) for rotating the phase adjustment gear ( 26 ), wherein the electric motor ( 28 ) drives the phase adjustment gear ( 26 ) in rotational movement, thereby changing an angular position of the carrier ( 22 ) resulting in the cam phase position change of the camshaft ( 24 ) relative to the crankshaft ( 34 ); and
adjustably varying a cam phase position of the camshaft ( 24 ) relative to the crankshaft ( 34 ) with rotational movement of the phase adjustment gear ( 26 ).

15. The method of claim 14 further comprising:
measuring a current position of the cam sprocket ( 20 ) relative to the camshaft ( 24 ) with a sensor ( 30 ); and
providing a feedback signal from the sensor ( 30 ) to a controller ( 32 ) of the electric motor ( 28 ) to determine if a cam phase position adjustment is required.

Assignees

• Borgwarner Inc

Inventors

• Showalter Dan J

Classifications

• F16H1/28

  with gears having orbital motion · CPC title

• Y10T29/49295

  Push rod or rocker arm making · CPC title

• F01L1/34 Primary

  characterised by the provision of means for changing the timing of the valves without changing the duration of opening {and without affecting the magnitude of the valve lift} · CPC title

• F01L1/344

  changing the angular relationship between crankshaft and camshaft, e.g. using helicoidal gear · CPC title

• F01L1/352 Primary

  using bevel or epicyclic gear · CPC title