Valve timing adjustment device

Patent metadata

Field	Value
Publication number	US-11459916-B2
Application number	US-202117473503-A
Country	US
Kind code	B2
Filing date	Sep 13, 2021
Priority date	Mar 15, 2019
Publication date	Oct 4, 2022
Grant date	Oct 4, 2022

Abstract

A drive-side rotor is rotated synchronously with a crankshaft. A driven-side rotor is rotated integrally with a camshaft. An internal gear section is formed at the driven-side rotor. An Oldham coupling includes: a driven Oldham flange that is formed at the drive-side rotor; a drive Oldham flange that is formed at the planetary rotor; and an Oldham intermediate that is configured to synchronize rotation of the driven Oldham flange and rotation of the drive Oldham flange while permitting eccentricity between the driven Oldham flange and the drive Oldham flange. There is satisfied a relationship of θ 2<θ1 where: θ 1 is a maximum tilt amount of the planetary rotor relative to the driven Oldham flange; and θ 2 is a maximum tilt amount of the planetary rotor in a clearance formed at the Oldham coupling.

First claim

What is claimed is:

1. A valve timing adjustment device for adjusting a valve timing of a valve that is opened and closed by a camshaft with a torque transmitted from a crankshaft at an internal combustion engine, the valve timing adjustment device comprising:
a drive-side rotor that is configured to be rotated synchronously with the crankshaft about a rotation center axis that is coaxial with the camshaft;
a driven-side rotor that is configured to be rotated integrally with the camshaft about the rotation center axis;
an internal gear section that is formed at one of the driven-side rotor and the drive-side rotor;
a planetary rotor that has a planetary gear section which is eccentric to the rotation center axis and is meshed with the internal gear section; and
an Oldham coupling that includes:
a driven Oldham flange that is formed at another one of the driven-side rotor and the drive-side rotor;
a drive Oldham flange that is formed at the planetary rotor; and
an Oldham intermediate that is configured to synchronize rotation of the driven Oldham flange and rotation of the drive Oldham flange while permitting eccentricity between the driven Oldham flange and the drive Oldham flange, wherein:

the valve timing adjustment device is configured to satisfy a relationship of θ 2 <θ 1 where: θ 1 is a maximum tilt amount of the planetary rotor relative to the driven Oldham flange; and θ 2 is a maximum tilt amount of the planetary rotor in a clearance formed at the Oldham coupling.

2. The valve timing adjustment device according to claim 1 , wherein:
the valve timing adjustment device is further configured to satisfy all of relationships of:
θ 1 =arctan (CL 5 /L 3 ); and
θ 2 =arctan ((CL 1 +CL 2 )/L 1 )+arctan ((CL 3 +CL 4 )/L 2 ), where:
CL 1 is one of two opposite axial clearances respectively formed between the Oldham intermediate and the drive-side rotor in an axial direction of the rotation center axis, and CL 2 is another one of the two opposite axial clearances respectively formed between the Oldham intermediate and the drive-side rotor in the axial direction;
L 1 is a diameter of an axially contacting part of the Oldham intermediate that is configured to axially contact the drive-side rotor;
CL 3 is one of two opposite circumferential clearances respectively formed between the planetary rotor and the Oldham intermediate in a circumferential direction, and CL 4 is another one of the two opposite circumferential clearances respectively formed between the planetary rotor and the Oldham intermediate in the circumferential direction;
L 2 is an axial length of a circumferentially contacting part of the Oldham intermediate that is configured to circumferentially contact the planetary rotor;
CL 5 is an axial clearance between the planetary rotor and the drive-side rotor; and
L 3 is a diameter of an axially contacting part of the planetary rotor that is configured to axially contact the drive-side rotor.

3. The valve timing adjustment device according to claim 1 , wherein a line of a force, which is radially applied to a meshing part between the internal gear section and the planetary gear section, and a line of a force, which is radially applied to the planetary rotor, are spaced from each other in the axial direction of the rotation center axis.

4. The valve timing adjustment device according to claim 1 , wherein:
the one of the driven-side rotor and the drive-side rotor, at which the internal gear section is formed, has a bearing portion that rotatably and radially supports the another one of the driven-side rotor and the drive-side rotor; and
a line of a force, which is radially applied to a meshing part between the internal gear section and the planetary gear section, and a line of a force, which is radially applied to the bearing portion, are spaced from each other in the axial direction of the rotation center axis.

5. The valve timing adjustment device according to claim 1 , wherein:
the drive-side rotor includes:
a bearing portion that rotatably and radially supports the driven-side rotor; and
an engaging portion, to which a looped transmission member configured to transmit the torque from the crankshaft is engaged; and

a line of a force, which is radially applied to the bearing portion, and a line of a force, which is radially applied from the looped transmission member to the engaging portion, are spaced from each other in the axial direction of the rotation center axis.

6. The valve timing adjustment device according to claim 1 , wherein the Oldham intermediate is configured to generate an urging force for urging the driven Oldham flange and the drive Oldham flange away from each other.

7. The valve timing adjustment device according to claim 6 , wherein:
at least a portion of the Oldham intermediate is made of a resilient material; and
a direction of an urging force generated by the Oldham intermediate is tilted relative to the rotation center axis.

8. The valve timing adjustment device according to claim 6 , wherein at least a portion of a circumferentially contacting part of the Oldham intermediate, which is configured to circumferentially contact the drive-side rotor, is tilted relative to an axis of the Oldham intermediate and is configured to generate an axial force component upon application of a circumferential load to the circumferentially contacting part of the Oldham intermediate in response to transmission of the torque to urge the driven Oldham flange and the drive Oldham flange away from each other with the axial force component.

Assignees

• Denso Corp

Inventors

• Otsubo Makoto
• Tomomatsu Kenichi
• Yamamoto Shuhei
• Takahashi Hiroki
• Kinouchi Soichi

Classifications

• F01L1/352 Primary

  using bevel or epicyclic gear · CPC title

• F16H2001/326

  comprising linear guiding means guiding at least one orbital gear · CPC title

• F01L1/356

  making the angular relationship oscillate {, e.g. non-homokinetic drive} · CPC title

• F16H35/008

  for variation of rotational phase relationship, e.g. angular relationship between input and output shaft · CPC title

• F16H1/32 Primary

  in which the central axis of the gearing lies inside the periphery of an orbital gear · CPC title