Metal treatment – Process of modifying or maintaining internal physical... – Carburizing or nitriding using externally supplied carbon or...
Reexamination Certificate
2000-02-24
2001-10-16
Echols, P. W. (Department: 3726)
Metal treatment
Process of modifying or maintaining internal physical...
Carburizing or nitriding using externally supplied carbon or...
C148S211000, C148S222000, C148S233000, C029S892000, C474S008000
Reexamination Certificate
active
06302971
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a pulley useable in a belt-driven continuously variable transmission (CVT), for example, a belt-driven CVT as a power transmission of vehicles, and to a process for making a moveable pulley half of the pulley.
There is a known belt-driven CVT as shown in FIG.
5
. The belt-driven CVT includes an input pulley
102
mounted to an input shaft
101
drivingly connected with a power source, an output pulley
103
mounted to an output shaft (not shown), and an endless driving belt
104
connecting the input and output pulleys
102
and
103
. The input pulley
102
includes a fixed pulley half
105
integrally formed with the input shaft
101
and a moveable pulley half
106
reciprocally moveable in an axial direction of the input shaft
101
. The fixed and moveable pulley halves
105
and
106
include tapered contact surfaces
105
a
and
106
a
that are axially opposed to each other and frictionally contacted with the driving belt
104
. Similarly, the output pulley
103
includes fixed and moveable pulley halves
107
and
108
having tapered contact surfaces
107
a
and
108
a,
respectively. The driving belt
104
displaces in a radial direction of each pulley
102
and
103
as the moveable pulley half
106
and
108
of the pulley
102
and
103
reciprocally moves. The revolution of the input rotating shaft
101
is continuously variably transmitted to the output rotating shaft through the input and output pulleys
102
and
103
and the driving belt
104
depending on continuous radial displacement of the driving belt
104
. The moveable pulley half
106
of the input pulley
102
includes a shaft portion
109
mounted to the input shaft
101
, a radially outwardly extending flange portion connected with the shaft portion
109
, a step portion
111
formed in the flange portion, and an annular cylinder member
110
press-fitted to the step portion
111
. The cylinder member
110
fixed to the moveable pulley half
106
is slidably received within a partition wall
115
and cooperates therewith to define a pressure chamber therebetween. Working fluid is fed to the pressure chamber through a communication hole
112
formed in the shaft portion
109
. The output pulley
103
has substantially the same structure as that of the input pulley
102
.
The moveable pulley half
106
with the cylinder member
110
is formed by the process shown in
FIGS. 6A-6F
. In
FIGS. 6A-6F
, only an upper half of a cross-section of the moveable pulley half
106
taken along an axis thereof is shown for the purpose of simple illustration.
FIGS. 6E and 6F
also show only an upper half of a cross-section of the cylinder member
110
.
As illustrated in
FIG. 6A
, a workpiece
150
having a predetermined shape is formed by forging. Then, as illustrated in
FIG. 6B
, the workpiece
150
is machined to form the shaft portion
109
, the flange portion, the step portion
111
and the communication hole
112
. The workpiece
150
machined is heat-treated as indicated by the broken line in FIG.
6
C. As illustrated in
FIG. 6D
, the workpiece
150
heat-treated is then finished to form the moveable pulley half
106
having the contact surface
106
a.
On the other hand, the cylinder member
110
is formed from sheet metal by a suitable method such as pressing, as shown in FIG.
6
E. Finally, as illustrated in
FIG. 6F
, the cylinder member
110
is press-fitted to the step portion
111
of the moveable pulley half
106
. Incidentally, the communication hole
112
is formed before the press-fitting of the cylinder member
110
because the cylinder member
110
is located on a hypothetical extension line extending in a longitudinal direction of the communication hole
112
.
SUMMARY OF THE INVENTION
In the above-described conventional arrangement, the moveable pulley half
106
has an increased thickness at the step portion
111
for mounting the cylinder member
110
, resulting in an undesirable increased weight of the pulley half as a whole. Additionally, it is required that assembling work of the moveable pulley half
106
and the cylinder member
110
is done with high accuracy, resulting in an increased manufacturing cost.
There is a demand for providing an arrangement useable in the belt-driven continuously variable transmission (CVT), that is capable of solving the problems described above.
It is an object of the present invention to provide a pulley for a belt-driven CVT in which a moveable pulley half of the pulley has a reduced weight and an improved cost performance, and a process for making the moveable pulley half.
According to one aspect of the present invention, there is provided a process for making a moveable pulley half of a pulley useable with an endless driving belt in a continuously variable transmission, said moveable pulley half having an axis and including a hollow shaft portion axially extending, a radially outwardly extending flange portion connected with the shaft portion and formed with a contact surface frictionally contacted with the driving belt, and an integral cylinder portion axially extending at near an outer periphery of the flange portion, said process comprising:
forming a workpiece including a hub wall having a cylindrical bore having a center axis and a flange wall extending perpendicular to the center axis from the hub wall;
machining the workpiece to form the shaft portion from the hub wall, a preformed flange having a truncated conical surface from the flange wall, a thickened peripheral portion axially extending from an outer circumferential portion of the preformed flange, and a communication hole communicating with the cylindrical bore;
spinning the workpiece to form the integral cylinder portion from the thickened peripheral portion;
heat-treating the workpiece; and
finishing the workpiece to complete the moveable pulley half including the flange portion having the contact surface.
According to a further aspect of the present invention, there is provided A pulley useable with an endless driving belt in a continuously variable transmission, said pulley having an axis and including an axially moveable pulley half, said moveable pulley half including a hollow shaft portion axially extending, a radially outwardly extending flange portion connected with the shaft portion and formed with a contact surface contacted with the driving belt, and an integral cylinder portion axially extending at near an outer periphery of the flange portion, said moveable pulley half being made by a process comprising:
forming a workpiece including a hub wall having a cylindrical bore having a center axis and a flange wall extending perpendicular to the center axis from the hub wall:
machining the workpiece to form the shaft portion from the hub wall, a preformed flange having a truncated conical surface from the flange wall, a thickened peripheral portion axially extending from an outer circumferential portion of the preformed flange, and a communication hole communicating with the cylindrical bore;
spinning the workpiece to form the integral cylinder portion from the thickened peripheral portion;
heat-treating the workpiece; and
finishing the workpiece to complete the moveable pulley half including the flange portion having the contact surface.
REFERENCES:
patent: 4504246 (1985-03-01), Mott
patent: 4617004 (1986-10-01), Mott
patent: 4731044 (1988-03-01), Mott
patent: 5270374 (1993-12-01), Ratliff
patent: 5528952 (1996-06-01), Takita et al.
patent: 6146294 (2000-11-01), Bolz
patent: 62-28566-A (1987-02-01), None
patent: 63-115966-A (1988-05-01), None
Nishimura Fumitaka
Ohara Yujiro
Echols P. W.
McDermott & Will & Emery
Nissan Motor Co,. Ltd.
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