[in Japanese]

View full abstract

Applying the vibrational motion A cos (pt+φ) +Bcos 2pt to a conveying deck, the conveying velocity V of the body on the deck is given theoretically
V/pA=-2 εcos (πδ+2φ),
if ε=B/A<<1, δ=μg/A/p<<1. Here p is the fundamental angular velocity of the deck, μ the coefficient of friction, A the amplitude of the fundamental vibration, B the amplitude of 2nd order harmonics and g the acceleration of gravity.
Moreover V/pA for the ordinary values of ε and δ is calculated by analog computer using ε, δ and φ as a parameter. As the result, the maximum value of V/pA is obtained when ε=0.25, δ=0. 2 and φ=80°, 170°. Therefore, a maximum conveying velocity can be required from the above conditions when the velocity amplitude of the deck is constant. Reversely when the velocity is given, a necessary minimum velocity amplitude of the deck can be calculated.
The above theoretical results are ascertained experimentally.

View full abstract

Owing to the constructionrof the vibrating body and the absence of the bearings, the vibratory gyro has a number of advantages over the conventional rotating-wheel gyro, such as ruggedness, simplicity, long life, rapid response, wide range of rate measured with good linearity.
An experimental study on an outline of characteristics of vibratory gyros is reported in this paper in which the tuning-fork type gyro having a certain amount of moment of inertia is compared with the tuning-ring type gyro having the same amount of moment of inertia, for the purpose of making a general engineering application, as against inertial guidance where extreme sensitivity and stability may be required.
The results obtained are as follows :
1) As for response, the tuning-ring gyro is superior to the tuning-fork gyro.
2) Asirto linearity, the tuning-fork gyro is superior at the rate of less than 0.1 rad/s, namely at low speed, while the tuning-ring gyro is superior more than 3 radfs at high speed.
3) The tuning-fork gyro is much influenced by centrifugal force and eccentricity of the gyro's axis.
4) The resonance of the torque pick-up and vibrating mass can be obtained more easily in the case of the tuning-fork gyro.

View full abstract

An accumulation phenomenon in grinding leads to the existence of three distinct states in a grinding cycle, a state of spark-in grinding at the beginning of grinding, a steady state and a state of spark-out grinding after stopping the infeed of grinding wheel.
The purpose of this study is to get a foundation for scientific understanding of grinding process by analyzing the transient characteristics in grinding and combining the analysis with that of grinding proCess in the steady state.
In this paper discussed is effects of such grinding conditions upon the transient characteristics as speed ratio, grinding speed, stiffness of grinding system, wheel grade and dressing conditions. It has been made clear that both spark-in and spark-out grinding time decrease with increasing speed ratio and grinding speed, with higher stiffness of grinding system, with weaker grade of wheel and with coarser dressing.

View full abstract

Generation and growth of chattering phenomena are studied experimentally in cylindrical plunge grinding process of hardened steel. Individual properties and mutual relations are examined of such measured values as machine vibration, grinding force and wheel circumferential profile. Main symptoms of chatter vibration and their reciprocal correlations are able to be explained as follows in reference to the variation of static grinding force.
In the grinding process, relative vibration between workpiece and wheel grows at the frequency coincident with the natural frequency of grinding system. Waviness is formed on the wheel circumference. In the region where the grinding force grows, however, natural frequency increases with time through the increase of grinding stiffness. Accordingly, pitch of wheel waviness tends to change and height of waviness does not develop. Amplitude of vibration is also limited in trifle.
Since the grinding stiffness shows almost constant value in the region of the saturated grinding force, natural frequency is fixed and resonant state is kept during a certain time. Waviness develops and vibration becomes larger exponentially, and then chattering marks appear on the ground surface.

View full abstract