Valve timing control apparatus for internal combustion engine

Patent metadata

Field	Value
Publication number	US-9765653-B2
Application number	US-201514931341-A
Country	US
Kind code	B2
Filing date	Nov 3, 2015
Priority date	Nov 4, 2014
Publication date	Sep 19, 2017
Grant date	Sep 19, 2017

Abstract

A valve timing control apparatus for an internal combustion engine includes a driving rotation member to which rotation of a crankshaft is transmitted, a driven rotation member coupled to a camshaft so as to be rotatable relative to the driving rotation member, an electric motor having a motor output shaft to cause rotation of the driven rotation member relative to the driving rotation member, a cover member arranged axially facing a front end portion of the motor output shaft and an electromagnetic induction type rotational angle detection mechanism disposed between the motor output shaft and the cover member so as to detect a rotational angle of the motor output shaft. The rotational angle detection mechanism has a detected part provided to the front end portion of the motor output shaft and a detecting part provided to a portion of the cover member axially facing the detected part.

First claim

What is claimed is:

1. A valve timing control apparatus for an internal combustion engine, comprising:
a driving rotation member to which rotation of a crankshaft is transmitted;
a driven rotation member coupled to a camshaft so as to be rotatable relative to the driving rotation member;
an electric motor having a motor output shaft to cause rotation of the driven rotation member relative to the driving rotation member;
a cover member arranged axially facing a front end portion of the motor output shaft; and
an electromagnetic induction type rotational angle detection mechanism disposed between the motor output shaft and the cover member so as to detect a rotational angle of the motor output shaft,
wherein the rotational angle detection mechanism comprises:
a detected part provided to the front end portion of the motor output shaft; and
a detecting part provided to a portion of the cover member axially facing the detected part;

wherein the detected part has a noncircular exciting conductor;
wherein the detecting part has a receiving coil, an exciting coil and a detection circuit to detect a change in inductance between the receiving coil and the exciting conductor and determine the rotational angle of the motor output shaft based on the detected change in inductance;
wherein a bolt insertion hole is formed axially in the motor output shaft such that a cam bolt is inserted in the bolt insertion hole;
wherein the detected part is partially inserted in the bolt insertion hole; and
wherein the exciting conductor is fixed to a front end face of the detected part.

2. The valve timing control apparatus according to claim 1 ,
wherein the detected part has a substantially cylindrical support body arranged such that a rear end portion of the support body is inserted and fixed in the bolt insertion hole.

3. The valve timing control apparatus according to claim 1 ,
wherein the detected part has a seal member retained at an outer circumference thereof and elastically brought into contact with an inner circumferential surface of the bolt insertion hole so as to provide a seal between the detected part and the bolt insertion hole.

4. The valve timing control apparatus according to claim 3 ,
wherein the motor output shaft has an annular protrusion formed integrally on the inner circumferential surface of the bolt insertion hole and a locking groove formed in the inner circumferential surface of the bolt insertion hole at a position front of the annular protrusion;
wherein the seal member is axially elastically brought into contact with the annular protrusion; and
wherein the detected part has a locking piece formed on an outer circumferential surface of the support body at a position front of the seal member so as to engage in the locking groove by axial elastic reaction force of the seal member.

5. The valve timing control apparatus according to claim 2 ,
wherein the support body has an annular stopper formed on an outer circumferential surface thereof for positioning of the support body in the bolt insertion hole; and
wherein the detected part has a fixing member arranged to cover an outer circumferential surface of the annular stopper and fix the support body to the front end portion of the motor output shaft.

6. The valve timing control apparatus according to claim 1 ,
wherein the detected part has a cylindrical support body formed of a synthetic resin material; and
wherein the exciting conductor is fixed by resin molding to a front end face of the support body.

7. The valve timing control apparatus according to claim 6 ,
wherein the detected part has a seal member retained around a rear end portion of the support body to provide a seal between an outer circumferential surface of the support body and an inner circumferential surface of the motor output shaft.

8. The valve timing control apparatus according to claim 6 ,
wherein the support body is formed into a bottomed cylindrical shape with a bottom wall; and
wherein the exciting conductor is fixed by resin molding to an outer surface of the bottom wall of the support body.

9. The valve timing control apparatus according to claim 8 ,
wherein the detecting part is fixed to the cover member; and
wherein a resin material is arranged between the detecting part and the detected part.

10. A valve timing control apparatus for an internal combustion engine, comprising:
a driving rotation member to which rotation of a crankshaft is transmitted;
a driven rotation member coupled to a camshaft by a cam bolt so as to be rotatable relative to the driving rotation member;
an electric motor integrally mounted on the driving rotation member and having a motor rotation shaft rotated to cause rotation of the driven rotation member relative to the driving rotation member;
a cover member arranged axially facing a front end portion of the motor output shaft; and
an electromagnetic induction type rotational angle detection mechanism disposed between the motor output shaft and the cover member so as to detect a rotational angle of the motor output shaft,
wherein the rotational angle detection mechanism comprises:
a detected part provided to the front end portion of the motor output shaft and having an exciting conductor fixed to a front end face of the detected part;
a circuit board fixed to the cover member;
receiving and exciting coils mounted on the circuit board; and
a detection circuit mounted on the circuit board to detect a change in inductance between the receiving coil and the exciting conductor and determine the rotational angle of the motor output shaft based on the detected change in inductance,

wherein a bolt insertion hole is formed axially in the motor output shaft such that the cam bolt is inserted in the bolt insertion hole; and
wherein the detected part is partially inserted in a front end region of the bolt insertion hole, with the exciting conductor remaining exposed from the front end region of the bolt insertion hole.

11. The valve timing control apparatus according to claim 10 ,
wherein the detected part has a cylindrical support body formed of a synthetic resin material; and
wherein the exciting conductor is fixed by resin molding to a front end face of the support body.

Assignees

• Hitachi Automotive Systems Ltd

Inventors

• Kajiura Mikihiro
• Iwase Yosuke

Classifications

• F01L2820/032

  Electric motors · CPC title

• F01L2301/00

  Using particular materials · CPC title

• F01L2810/02

  Lubrication · CPC title

• F01L2201/00

  Electronic control systems; Apparatus or methods therefor · CPC title

• F01L2250/02

  the camshaft being driven by chains · CPC title