Valve timing control device

Details Valve timing control device Valve timing control device

1998-09-29

2001-01-16

Lo, Weilun (Department: 3748)

Internal-combustion engines

Poppet valve operating mechanism

With means for varying timing

C123S090310

Reexamination Certificate

active

06173686

ABSTRACT:

BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
The present invention relates to a valve timing control device and, in particular, to a valve timing control device for controlling an angular phase differential between a crank shaft of a combustion engine and a cam shaft of a combustion engine.
BACKGROUND OF THE INVENTION
A conventional valve timing control device is disclosed, for example, in U.S. Pat. No. 4,858,572. As shown in
FIGS. 9 and 10
, this device includes a cam shaft
204
, a timing pulley
201
(rotational transmitting member), six vanes
202
, six chambers and a fluid supplying means. The cam shaft
204
is integrally formed with an internal rotor
203
by a bolt
220
and a spacer
221
. The cam shaft
204
is rotatably assembled with a cylinder head
214
of an internal combustion engine. The timing pulley
201
is driven by the rotational torque from a crank shaft (not shown) and mounted on the cam shaft so as to surround the internal rotor
203
. Six chambers are defined between the timing pulley
201
, the internal rotor
203
and a front plate
205
. The front plate
205
is integrally fixed on the timing pulley
201
. Each chamber is separated into an advancing chamber
209
and a delaying chamber
209
a
. A fluid supplying means include a changeover valve
215
which supplies fluid under pressure to at least a selected one of the advancing chambers
209
and the delaying chambers
209
a
so as to rotate relative between the cam shaft
204
and the timing pulley
201
. When a solenoid
213
of the changeover valve
215
is not energized, a spool
218
is located (shown in
FIG. 9
such that a feed port
212
, as connected to an oil pump (not shown) to be driven by the internal combustion engine of the changeover valve
215
and a passage
211
are connected to each other. The passage
211
leads to one of the advancing chambers
209
or the delaying chambers
209
a
. The oil pump provides the feed port
212
with fluid under pressure. When the solenoid
213
of the changeover valve
215
is energized, the spool
218
is urged to slide to the right direction in
FIG. 9
against the action of a spring
216
so that a feed port
212
and a passage
210
are connected to each other. The passage
211
leads to the other of the advancing chambers
209
or the delaying chambers
209
a
. The fluid under pressure in the advancing chambers
209
and the delaying chambers
209
a
is thereby controlled by the changeover valve so as to determine the relative position between the cam shaft
204
and the timing pulley
201
.
In the above-mentioned prior art device, the timing pulley
201
has six projections
201
b
. Each projection
201
b
extends in an inward direction. The top portion of the projections
201
b
engages with the peripheral surface of the internal rotor
203
. Both side walls
208
of the projection
201
b
are able to contact with the vane
202
so as to decide the relative rotational angle (&THgr;) between the cam shaft
204
and the timing pulley
201
. The elaborate construction of the internal rotor
203
, vanes
202
and the timing pulley
201
is necessary so that each relative position between the vane
202
and chamber is in the same proportion. The manufacturing cost of these parts, therefore, is expensive.
SUMMARY OF THE INENTION
Accordingly, it is an object of the present invention to provide an improved valve timing control device without the foregoing drawbacks.
In accordance with the present invention, a valve timing control device comprising a cam shaft rotatably assembled with a cylinder head of an engine, a rotational transmitting member having a concave portion which is located on the inside surface thereof, with the rotational transmitting member mounted around the peripheral surface of the cam shaft so as to rotate relative thereto within a predetermined range for transmitting a rotational power from a crank pulley, a plurality of vanes provided on the cam shaft or the rotational transmitting member, fluid chambers formed between the cam shaft and the concave portion of the rotational transmitting member and separated into advancing chambers and delaying chambers by the vanes, a fluid supplying means for supplying fluid under pressure to at least a selected one of the advancing chambers and delaying chambers and a stopper located between a top portion of a side wall of the concave portion of the rotational transmitting member and the vane so as to restrict rotation relative between the rotational transmitting member and the cam shaft.
Other objects and advantages of invention will become apparent during the following discussion of the accompanying drawings.


REFERENCES:
patent: 4858572 (1989-08-01), Shirai et al.
patent: 5832887 (1998-11-01), Adachi et al.
patent: 5937810 (1999-08-01), Sato et al.
patent: 6035816 (2000-03-01), Ogawa et al.
patent: 196 23 818 (1996-12-01), None
patent: 0 777 037 (1997-06-01), None
patent: 2302391 (1997-01-01), None
patent: 9-60508 (1997-03-01), None
patent: 10-47022 (1998-02-01), None

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