Geometrical instruments – Gauge – Circular size
Reexamination Certificate
1999-02-04
2001-06-19
Bennett, G. Bradley (Department: 2859)
Geometrical instruments
Gauge
Circular size
C033S702000, C033S703000, C033S704000, C473S351000
Reexamination Certificate
active
06247241
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a ball diameter automatic measurement device and method for a rolling bearing. The present invention, more particularly, relates to ball diameter automatic measurement device and method which is capable of determining positions at which a ball are measured based upon the rotation of the ball, and capable of acquiring the average value of measured values and dispersion in the ball diameters at the various positions.
Further, the present invention also relates to ball diameter automatic measurement device and method which is free from the effect of body temperature and a personal error, and which is further hardly influenced by the fluctuation of air temperature.
Japanese Patent Examined Publication No. Hei. 6-54204 teaches a conventional ball diameter measurement device, in which a method of pressing and positioning a ball manually on three planes. The three planes are defined by an upper surface of a fixed board and a pair of surfaces of the notch of a notched groove of a ball holder. After positioning the ball on the three planes, the ball diameter is measured.
In the conventional ball diameter measurement device, as a ball is manually positioned at a measurement point by using a pair of tweezers, it is easily influenced by body temperature and then the temperature drift is large. Since distance between a hand for operating the tweezers and the ball held between the tweezers is so small, the ball is indispensably influenced by the body temperature. Also, as a ball is manually positioned in a measurement position using tweezers, measurement device cannot be covered or accommodated within a closed box having a cover, and then it is readily influenced by the fluctuation of air temperature. Further, as a ball is manually positioned at the measuring position, a personal error is readily made. Therefore, there is a problem that it is difficult to acquire the measurement precision of ±0.01 &mgr;m or less.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a ball diameter automatic measurement device which is free from the effect of body temperature and removes the effect of the fluctuation of air temperature when the ball diameter is measured, and simultaneously enables a predetermined accurate measurement independent of the individual operator's talent or art.
The above-mentioned object can be attained by a ball diameter measurement device, according to the present invention, comprising: a ball movement means, means for changing the phase of the diameter of a ball, and measurement control means which are provided to measure the diameter of a ball.
The ball diameter automatic measurement device, according to the present invention, preferably comprises:
a displacement sensor for measuring the diameter of a ball positioned in a measurement position;
a dividing plate holding a ball to be measured which can be reciprocated between a predetermined position and the measurement position;
a slider for rotating the ball in the predetermined position by a predetermined angle as the dividing plate is moved; and
measurement control means for storing and outputting measured values obtained by repeated measurement and measurement after the rotation of the predetermined angle.
In the above-mentioned construction, the above ball to be measured denotes a measured ball or a master ball.
The above object can also be achieved by a ball diameter automatic measuring method, according to the present invention, comprising the steps in sequence of:
moving a ball held on a dividing plate under a displacement sensor in a measurement position
holding the ball between a gauge element located under the displacement sensor and a measuring table,
applying pressure to the ball by the gauge element and storing vertically fluctuating values of the core of the displacement sensor,
moving the ball held on the dividing plate to a slider,
rotating the ball on the slider by a predetermined angle and moving the dividing plate,
positioning it under the displacement sensor in the measurement position again,
applying pressure to the ball by the gauge element, and
storing the fluctuating values of the core of the displacement sensor,
in which the above-mentioned sequential steps are repeated by predetermined times, and an average value and standard deviation are calculated based upon the stored values.
The above ball movement means denotes means for holding a measured ball on a dividing plate which can be reciprocated and moving the ball between a predetermined position and a measurement position and concretely, denotes means for locating a ball in a ball holding hole slightly larger than the diameter of the ball and provided to a dividing plate, rolling the ball on a measuring table as the dividing plate is moved and moving the ball between a predetermined position and a measurement position.
Also, the above means for changing the phase of the diameter of a ball denotes means for rotating a ball positioned in a position for changing a phase by a predetermined angle to change a position in which the diameter of the ball is measured, and concretely, denotes means for rotating the ball in a ball holding hole positioned on a slider by a predetermined angle by moving the slider. At that time, the slider is moved in a direction different from a direction in which a dividing plate is moved. For example, a phase is changed by rolling a ball by desired quantity in a direction perpendicular to a rolling direction by the movement of a dividing plate. As the ball is never rolled in this direction except changing a phase, accidental sliding and others hardly occur and a position for measuring the diameter of a ball after rolling is securely different from a measurement position before rolling. A phase can be also changed through a process of once positioning a ball before a ball measurement position, sliding the ball by moving a dividing plate afterward and positioning the ball in the ball measurement position at the time of measurement, and this can be also combined with changing a phase in the above perpendicular direction. That is, it is because the distance of a ball from a phase changing position to a measurement position (the number of the revolution of the ball) and the return distance of the ball from the measurement position to the phase changing position (the number of the revolution of the ball) are different.
Further, the above measurement control means denotes means for storing measured values obtained by repeating a process of measuring after predetermined times and measuring after a phase is changed per one ball, executing statistical processing and outputting it. Concretely, the above means denotes means for converting measured values from analog to digital, storing them in the memory of a computer and others and calculating the average value of measured values and a situation of the distribution of measured values such as the deviation (so called as deviation) of a diameter, for example 6&sgr;, skewness and the degree of a gradient.
Temperature change compensating means can be also added to the above-mentioned device. As the temperature change compensating means, a drift compensating measurement system for compensating drift having the substantially same construction as a main measurement system described above is provided. The drift compensating measurement system is provided with a displacement sensor for measuring the diameter of a ball located in a measurement position which is provided on the opposite side to the main measurement system. In a measurement position in the drift compensating measurement system, a drift compensating ball, a member for positioning the drift compensating ball, a gauge element supporting part holding a gauge element for applying pressure to a ball to be measured positioned on a measuring table and the drift compensating ball in a concave portion on the side of a measuring column, a sensor lifting cylinder arranged in the hole of the measuring column to lift the above gauge element supporting
Bennett G. Bradley
NSK Ltd.
Sughrue Mion Zinn Macpeak & Seas, PLLC
Verbitsky Gail
LandOfFree
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