Abrading – Machine – Rotary reciprocating tool
Reexamination Certificate
1999-12-13
2001-08-21
Eley, Timothy V. (Department: 3723)
Abrading
Machine
Rotary reciprocating tool
C451S139000, C451S005000, C451S011000
Reexamination Certificate
active
06277004
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a phase adjusting method which, in a work with a recess formed around the axis of the work, positions the recess around the axis of the work. In addition, the present invention also relates to a recess machining apparatus and method for producing a work with a recess formed around its axis in which the recess of the work can be accurately positioned and then machined.
For example, a loading cam mechanism of a troidal-type continuously variable transmission used as a transmission for a car includes a cam disk and a roller. The cam disk is formed in a disk shape which is symmetric with respect to the axis of the cam disk. Also, the cam disk includes an end face, which is formed symmetric with respect to the above-mentioned axis and extends in a flat manner along a direction meeting at right angles to the above-mentioned axis, and a plurality of cam surfaces each of which has a concave shape extending from the end face and is formed at positions spaced at equal intervals along the peripheral direction of the cam disk.
Each of the cam surfaces includes a pair of inclined surfaces respectively formed inclined with respect to the end face of the cam disk and opposed to each other, and an arc surface connecting the pair of inclined surfaces to each other.
To manufacture a work such as the above-mentioned cam disk which includes an end face formed symmetric with respect to the axis of the work and a plurality of cam surfaces respectively formed in a concave manner from the end face of the work and arranged at equal intervals along the peripheral direction of the work, normally, there is employed a manufacturing method which comprises the following two steps: that is, one is a rough machining step in which a cylindrical-shaped blank member is forged or cut to thereby produce once an intermediate product close in shape to the above-mentioned cam disk; and, the other is a finishing step in which a grinding operation or a similar finishing operation is executed on the thus produced intermediate product to thereby obtain a cam disk having a final shape.
The intermediate product
62
(which is hereinafter referred to as a work) obtained through the rough working step, as shown in FIG.
13
and in other figures, is formed in a disk shape which is symmetric with respect to the axis P
2
thereof. The work
62
includes an end face
63
, which is formed symmetric with respect to the axis P
2
and extends in a flat manner along a direction meeting at right angles to the axis P
2
, and a plurality of recesses
64
which are respectively formed in a concave manner and are disposed at equal intervals along the peripheral direction of the work
62
. By the way, these recesses
64
correspond to the above-mentioned cam surfaces.
When carrying out a grinding operation or a similar finishing operation on the work
62
obtained through the rough working step, it is necessary to position a tool such as a grindstone or the like at a position which corresponds to the above-mentioned recesses
64
. For this reason, a proper position relationship between the recesses
64
and tool must be maintained by using means which can position or set the position of the recesses
64
around the axis P
2
at a given position.
Conventionally, in carrying out a grinding operation or a similar finishing operation on the above-mentioned work
62
, to keep a proper position relationship between the recesses
64
and tool, an operator positions the tool such as a grindstone or the like by hand in such a manner that it is contacted with the bottom
64
a
of the currently required one of the recesses
64
. An operation to position the recess
64
and tool in this manner not only demands skill from the operator but also is liable to lower the positioning accuracy of the work
62
around the axis P
2
. Further, such positioning operation provides a low operation efficiency and is thus liable to increase the manufacturing cost of the work
62
.
As the means for positioning the position of each of the recesses
64
around the axis P
2
at a given position, it can be expected to use a positioning jig. A positioning jig of this type includes a projection which can be engaged with and matched to any one of the recesses
64
. That is, when using such positioning jig, the projection thereof is engaged with and matched to the specific one of the recesses
64
to thereby position the work
62
. However, a phase adjusting method using this type of positioning jig is found that it is liable to lower the positioning accuracy of the work
62
around the axis P
2
; for example, the positioning accuracy of the work
62
around the axis P
2
is easy to vary.
SUMMARY OF THE INVENTION
The present invention aims at eliminating the drawbacks found in the above-mentioned conventional phase adjusting method.
Accordingly, it is an object of the invention to provide a phase adjusting method which is able to position each of the recesses of the work around the axis of the work with high accuracy and also to restrict an increase in the manufacturing cost of the work. In addition, it is also an object of the present invention to provide a recess machining apparatus and method for producing a work with a recess formed around its axis with high accuracy and also for restricting an increase in the manufacturing cost of the work.
In attaining the above object, according to the invention, there is provided a phase adjusting method for holding a work with a recess formed around the axis of the work and for positioning the position of the recess around the axis, the method comprising the steps of: holding the work in such a manner that it can be rotated around the axis of the work; detecting the position of the recess around the axis of the work; finding a rotation angle around the axis for positioning the recess at a given position around the axis of the work in accordance with the thus detected position of the recess around the axis of the work; and, rotating the work around the axis thereof in accordance with the thus found rotation angle to thereby position the recess at a given position around the axis of the work.
The above object can be achieved by a phase adjusting method for holding a work with a recess formed around the axis of the work and for positioning the recess around the axis at a predetermined rotational angular position, the method according to the present invention comprising the steps of:
holding the work;
detecting an initial angular position of a detecting point of the work at which a contact sensor is brought in contact with the work;
rotating the work in a first direction until the detecting point reaches a first angular position;
reverse-rotating the work in a second direction opposite to the first direction until the detecting point reaches a second angular position;
calculating an detected angular position on the basis of first and second angular positions and then calculating a rotation angle corresponding to a difference between the initial angular position and the detected angular position; and
adjusting a phase of the recess into a predetermined angular position by rotating the work around the axis in accordance with the rotation angle thus calculated.
In the phase adjusting method according to present invention, it is preferable that the angular position is an averaged angular position of the first and second angular positions.
In addition, in the phase adjusting method according to present invention, it is preferable to further comprise the steps of:
supplementally sensing a detecting point before the detecting step but after the holding step, and
rotating the work by 180 degree so as to conduct the detecting step.
Further, the above object can also be attained by a recess machining apparatus for manufacturing a work with recesses disposed in a circumferential direction at a predetermined interval, the recess machining apparatus according to the present invention comprising:
a holding and rotating member by which a work can be held at any angular positions and the work
Matsumoto Yasutami
Sakaguchi Tohru
Eley Timothy V.
Nguyen Dung Van
NSK Ltd.
Sughrue Mion Zinn Macpeak & Seas, PLLC
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