Geometrical instruments – Gauge – With support for gauged article
Reexamination Certificate
2001-09-26
2003-05-20
Gutierrez, Diego (Department: 2859)
Geometrical instruments
Gauge
With support for gauged article
C033S551000, C033S554000, C033S555100
Reexamination Certificate
active
06564466
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a measuring apparatus for pulley of a continuous variable transmission, and particularly relates to the measuring apparatus for the pulley that is capable of measuring configurations and positional accuracies of the pulley.
Generally, the pulley is a principal component of the continuous variable transmission. A movable pulley is fitted to a fixed pulley via a ball spline so as to rotate in opposite direction with respect to each other, and a pulley width between a conical surface of the fixed pulley and a conical surface of the movable pulley varies by the axial relative movement of the movable pulley.
In such a variable width pulley, it is required to evaluate the configuration/positional accuracies of a ball groove of a ball spline and a conical surface of the pulley in order to control the qualities. Therefore, conventionally the configurations are measured by providing detecting members that employ reference balls the number of which are the same as the grooves. Each of the reference balls has a specified diameter. The reference balls are pressed with a pressure via a spring into a groove portion on a workpiece, and then amounts of displacements are measured. That is, at this time, a circumferential displacement and a radial displacement are compared with a master. Alternatively, in the other conventional technology the configurations are measured with a copying/tracing measurement that utilizes a three-dimensional measuring apparatus.
In a Japanese Utility Model Laid-Open No. 56708/1994, disclosed is a technology for measuring an irregular relative movement (amount of angular displacement) between both of the workpieces when one of the workpieces is fixed and the other workpiece is rotated about the axis of the rotation by an actuator just as a male pulley and a female pulley are assembled.
However, with the measuring technology in which the detecting member using the reference ball of a specified diameter is pressurized into the groove, the configuration measurement of the ball groove, a tapered angle of the conical surface, and other geometric positional accuracy cannot be evaluated quantitatively. In addition to this, since the number of samplings is limited/reduced due to the fact that the number of the detecting member is limited, the repeatability is inappropriate. Further, the pressurizing force of the spring easily varies, thereby disadvantageously lowering a measuring accuracy and deteriorating a zero point setting accuracy at the time of master setting.
In the copying/tracing measurement by the three-dimensional measuring apparatus, the sampling point is rough (for example, 10 points/4 mm approx.), and thus it is difficult to measure with high accuracy because of variations in repeatability. Likewise, in the technology in which the irregular (backlash) movement of the pulley assembly in the assembled state is measured disclosed in the Japanese Utility Model Laid-Open No. 56708/1994, lack of information on the configuration or positional accuracy of the other parts other than the ball groove makes the accurate control difficult. In addition to this, in the case of assemblies having significant irregular movements, it may be necessary to follow up the cause by disassembling it again, which is troublesome and is not necessarily advantageous to the productivity and to the quality control.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a measuring apparatus for continuous variable transmission pulleys that can measure a configuration and a positional accuracy of a continuous variable transmission pulley quantitatively and can contribute to an improvement of a quality of finished products and lowering costs.
In order to achieve the above described object, a measuring apparatus for a pulley having a ball groove for a ball spline and a conical surface for varying a pulley width of the pulley, the measuring apparatus according to a first aspect of the present invention comprising:
a workpiece holding post for rotatably holding the pulley about an axis of the pulley;
a slide table slidable in a radial direction of the measuring apparatus;
a measuring post slidably mounted on the table in a tangent direction orthogonal to the radial direction of the measuring apparatus;
a detecting head slidably mounted on the measuring post in an axial direction orthogonal to both of the radial and tangent directions of the measuring apparatus, the detecting head having a probe including a ball of a specified diameter formed at the tip thereof; and
a processor for controlling movements of the slide table, the measuring post and the detecting head to allow the probe to be brought into contact with a portion of the pulley to-be-measured, and for measuring configurations and positional accuracy thereof based on displacement data detected by the detecting head.
In the measuring apparatus, it is preferable that the processor measures, at least one of:
(a) a groove diameter of the ball groove;
(b) an angle of intersection defined by intersecting a line connecting the center of an ideal circle and one of the two contact points and a line connecting the center of the ideal circle and the center of a measuring reference of the pulley when an ideal circle of a specified diameter is brought into contact with the ball groove at two contact points,
(c) a divided angle defined by intersecting lines connecting the center of a measuring reference of the pulley and each of the centers of a plurality of ideal circles, wherein each of the ideal circles has a specified diameter and is brought into contact with the respective ball groove at two contact points,
(d) a diameter of an outer circle of an ideal circle is, wherein the ideal circle has a specified diameter and is brought into contact with the respective ball groove at two contact points,
(e) a deviation between the center of a measuring reference of the pulley and the center of an outer circle to which a plurality of ideal circles are inscribed, wherein each of the ideal circles has a specified diameter and is brought into contact with the respective ball groove at two contact points,
(f) a diameter of an inner circle to which a plurality of ideal circles are circumscribed, wherein each of the ideal circles has a specified diameter and is brought into contact with the respective ball groove at two contact points,
(g) a deviation between the center of a measuring reference of the pulley and the center of an inner circle to which a plurality of said ideal circle are circumscribed, wherein the ideal circle has a specified diameter and is brought into contact with the respective ball groove at two contact points,
(h) circumferential and radial deviations in a lead of the ball groove,
(i) a tapered angle of the conical surface;
(j) a deviation in a normal direction with respect to a specified angle line of the conical surface, and
(k) a dimensional deviation with respect to a measuring reference of the conical surface.
In the above-mentioned measuring apparatus, it is preferable that the processor controls the slide table and the measuring post simultaneously to move the probe in the radial and tangential directions in the state of being in contact with the ball groove to carry out a copying measurement at many points, carries out circular-approximation by processing data on displacement in the radial direction and data on displacement in the tangential direction detected by the detecting head during the copying measurement at many points, and obtains an approximated diameter of the circle obtained by the circular-approximation as the groove diameter of the ball groove.
Further, in the measuring apparatus, it is preferable that the processor determines a measuring reference circle to which the tip of the prove should move based on several sampling data obtained prior to a copying measurement at many points, and controls the slide table and the measuring post simultaneously.
In the above-mentioned measuring apparatus, it is also preferable that the processor processes
Fuji Jukogyo Kabushiki Kaisha
Gutierrez Diego
Reis Travis
Smith Gambrell & Russell
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