Internal-combustion engines – Poppet valve operating mechanism – With means for varying timing
Reexamination Certificate
2000-10-17
2002-07-02
Lo, Wellun (Department: 3748)
Internal-combustion engines
Poppet valve operating mechanism
With means for varying timing
C123S090370, C074S56800M, C464S002000
Reexamination Certificate
active
06412463
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to valve timing regulation device for varying the opening and closing timing of one or both of an air-intake valve and an exhaust valve in response to performance conditions of an internal combustion engine.
2. Description of Related Art
FIG. 22
is a partial cross-sectional view of a conventional valve timing regulation device disclosed for example in JP-A-10-331613.
FIG. 23
is an enlarged cross-sectional view of a containing means.
In the figures,
101
is a cylindrical housing which is rotated by the output of the internal combustion engine. The housing
101
has a plurality of shoes
102
on an inner peripheral face. The shoes
102
extend in a radial direction of the housing
101
.
103
is a timing sprocket connected to one axial end of the housing
101
. The timing sprocket
103
is interlocked with the crankshaft of the internal combustion engine.
104
is a rotor which is housed to rotate relative to the housing
101
. The rotor
104
is connected to a camshaft (not shown) which opens and closes the air-intake and exhaust gas valves of the internal combustion. A plurality of vanes
105
which project between mutual vanes
102
project from an outer peripheral face of the rotor
104
.
106
is a retarding oil chamber for displacing each vane
105
in a retarding direction.
107
is an advancing oil chamber for displacing each vane
105
in an advancing direction. The retarding oil chamber
106
and the advancing oil chamber
107
are formed between the housing
101
and the rotor
104
by a space having a fan-shaped cross section which is formed between each vane
105
and each shoe
102
. A working oil is supplied to the retarding oil chamber
106
and the advancing oil chamber
107
.
108
is a seal mounting groove mounted on a tip of the vane
105
.
109
is a containing means fitted and retained in the seal mounting groove
108
. The containing means
109
comprises a seal member
110
having a spring housing groove
110
a
and a plate spring
111
housed in the spring housing groove
110
a.
The plate spring
111
presses the seal member
110
on the inner peripheral face of the housing
101
.
The groove opening side from the groove base of the spring housing groove
110
a
of the seal member
110
has approximately a trapezoid cross sectional shape, the width of which gradually narrows. Thus both inner wall faces of the spring housing groove
110
a
are inclined wall faces
110
b.
On the other hand, the plate spring
111
has a leg piece
111
b
with an expanding shape provided on both edges of the central curved section
111
a.
The central curved section
111
a
has a cross sectional shape approximately in the shape of a circular arc. Before mounting the plate spring
111
with respect to the spring housing groove
110
a,
the plate spring
111
is formed so that the open leg width of the leg piece
111
b
is wider than the width of the opening of the spring housing groove
110
a.
When assembling the containing means
109
, the leg piece
111
b
is pressed into the spring housing groove
110
a
of the seal member
110
while compressing the open leg width of the leg piece
111
b
of the plate spring
111
. The pressing of the leg piece
111
b
allows the leg piece
111
b
to be pressed onto and engaged with both inclined wall faces
110
b
of the spring housing groove
110
a.
Furthermore the tip of the leg piece
111
b
abuts with the bottom face of the spring housing groove
110
a.
In this position, the seal member
110
and the plate spring
111
are assembled integrally. A containing means
109
assembled in such a manner is inserted and fitted into the seal mounting groove
108
of the vane
105
during assembly of the housing
101
and the rotor
104
. When inserted and fitted, the seal member
110
is pressed onto the inner peripheral face of the housing
101
by the repulsive force of the plate spring
111
. Thus the sliding face of the vane
105
and the inner peripheral face of the housing
101
are sealed by the seal member
110
.
Since a conventional valve timing regulation device is comprised in the above manner, the leg piece
111
b
must be pressed into the spring housing groove
110
a
of the seal member
110
while compressing the leg piece
111
b
of the plate spring
111
during assembly of the containing means
109
. As a result, the problem has arisen that the mounting operation of the plate spring
111
with respect to the seal member
110
is difficult and requires considerable time. Furthermore the mounting of the containing means
109
on the valve timing regulation device is performed by inserting the containing means
109
from one end into the seal mounting groove
108
of the tip of the vane
105
with the rotor
104
fitted into the housing
101
. Thus during insertion, it is necessary to deform the plate spring
111
resiliently towards the bottom face of the spring housing groove
110
a.
However the plate spring
111
is fixed with the leg piece
111
b
of the plate spring
111
abutting under pressure with both inclined wall faces
110
b
of the spring housing groove
110
a
and the tip of-the leg piece
111
b
abutting with the bottom face of the spring housing groove
110
a.
As a result, it is difficult to create resilient deformation when insertion into the seal-mounting groove
108
is performed. Thus the problem has arisen that it is difficult to mount the containing means
109
with respect to the valve timing regulation device.
It has been proposed to reduce the spring constant of the plate spring more than necessary in order to solve the above problem. Thus in order to reduce the spring constant, it is necessary to reduce the width of the plate unnecessarily or to reduce the thickness of the plate. However such methods entail the disadvantage that durability of the components can not be maintained and breakage or damage of the plate spring occurs.
Other techniques about the conventional valve timing regulation device are disclosed for example in JP-A-11-30111. Since this valve timing regulation device has the object of preventing positional deviation of the plate spring in a transverse direction, the device does not comprise a detachment prevention structure for the plate spring and the seal member. As a result, when the seal member is assembled into the seal mounting groove, it is necessary to mount the seal member by insertion into the seal mounting groove while retaining the plate spring stored in the seal member mechanically or manually.
This type of mounting operation easily leads to detachment or separation of the plate spring during mounting. Thus for example, when mounting manually, unnecessary mounting time is required. Furthermore when mounting manually, designated mounting tools are required. Also a special detection means is required to detect detachment of the plate spring. In such a manner, unnecessary time is required for the mounting process or preparation for the mounting process. Thus productivity suffers greatly and as a result, the problem of increased costs results.
SUMMARY OF THE INVENTION
The present invention is proposed to solve the above problem and has the object of providing a valve timing regulation device which provides the seal member and plate spring as a pre-assembled unit and which allows easy insertion of both above components between the sliding peripheral faces of a first rotating body and a second rotating body. This arrangement results in improvements in productivity.
The present invention has the further object of providing a valve timing regulation device which allows the further simplification of insertion of the seal member, provided as a pre-assembled unit with the plate spring, between the sliding peripheral faces of the first rotating body and the second rotating body.
The present invention has the further object of providing a valve timing regulation device which allows smooth insertion of the seal member between the sliding peripheral faces of the first rotating body and the second ro
Lo Wellun
Sughrue & Mion, PLLC
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