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When the belt contacts a pulley in a pushing belt-type CVT, vibration is generated by frictional force due to rubbing between the individual elements that are components of the belt, which is said to increase wear and noise. The authors speculated that the source of that vibration is misalignment of the secondary pulley and primary pulley V-surfaces. To verify that phenomenon, a newly developed micro data logger was attached to an element of a mass-produced metal pushing V-belt CVT and the acceleration was measured at rotations equal to those at drive (1000 to 2500 r/m). In addition, the results of calculations using a behavior analysis model showed that changes in pulley misalignment influence element vibration, and that the magnitude of the vibration is correlated to the change in the metal pushing V-belt alignment immediately before the element contacts the pulley.

The metal pushing V-belt of a CVT equipped with a torque converter receives a sudden thrust load from the pulley when the CVT starts operation, and is required to begin transmitting torque from a stationary state with minimal time lag. In this study, the stress history of the area around the element neck under transient driving condition was clarified using new structural analysis technology to simultaneously simulate the dynamic behavior of the metal pushing V-belt and the element stresses. These results suggest that the compression stress generated by the load on the element V-surface is a fundamental component of element stress, and that bending stress generated by the compression force between the elements is superimposed on this stress. A comparison of simulation results with test results for the load distribution on the element, conducted to confirm the accuracy of the simulation, demonstrated good qualitative correlation.

A simulation method enabling simultaneous prediction of dynamic behavior and stress distribution on an individual element has been developed for durability evaluation of dynamic strength of metal pushing V-belts. The finite-element-method that enables contact analyses in time history with large-scale model was adopted to reproduce the dynamic behavior of the V-belt in high rotational speed range of CVT. This paper focuses on the element strength in actual CVT operation, and also discusses modifications made to the previously reported simulation method to enable the prediction of detailed stress. A new technique named inertia-relief is introduced, which does not require the application of constraint conditions when calculating the detailed stress on element in respectively. This results in allowing the stress distribution on any element to be found at any position on the trajectory of the V-belt and the elastic deformation of the element to be identified.

A simulation method was developed allowing simultaneous evaluation of dynamic behavior and stress for estimation of durability of metal pushing V-belts for CVT. This paper focuses on flexural behavior of the pulley, and the simulation method is newly improved to allow the pulley stiffness to be reflected. As a result, it is found that the flexural stiffness affects the ring impact stress at the pulley entrance and exit. Furthermore, the mechanism of contact between the ring edge and pulley surface or the element due to the ring misalignment caused by the pulley flexion is clarified. For the first time, these results make it possible to obtain a design guideline for the pulley stiffness that includes consideration of belt durability. This paper also refers to newly manufacturing metal V-belts, developed by Honda, which use this simulation to know the influence of some design changes.

A toroidal variator is the core part of an advanced Continuously Variable Transmission (CVT) design. Knowing its behavior and internal forces is key to defining the operational conditions of the transmission. To maintain a steady-state speed ratio, or to accurately and efficiently move between speed ratios, optimal trunnion control force is required. The unique design of the toroidal CVT makes the design very sensitive to trunnion positioning and force transients. Analytical understanding of the mechanism response is critical to toroidal variator controller design. A critical feature of the toroidal CVT simulation is representation of the friction forces in the disk-roller contact. This effect is important to the mechanism torque capacity and efficiency.

A pushing metal V-belt is the core part of a Continuously Variable Transmission (CVT). Knowing its behavior and internal forces is key to defining the operational conditions of the transmission. To maintain the steady-state speed ratio, an optimal pulley thrust is required. If the force is too large, the transmission efficiency is affected; if too small, the belt slips. Because so far the optimal value of the pulley thrusts had been derived from physical test, analytical understanding of this effect was lacking. In the physical test, controlled thrust is applied to one of the pulleys, further complicating the simulation process. This article describes a new simulation technique developed to resolve this problem. To predict the motion of the belt, a simulation was created, using a multi-body analysis code with a feedback control applied to the pulley thrust. The analysis model consisted of numerous elements, a multi-layer ring, and a pulley set.

A simulation technology has been developed to predict the transmission efficiency of a metal pushing V-belt and pulleys that make up the drive system of a continuously variable transmission (CVT). When a CVT operates in an actual vehicle, pulley thrust pressure is adjusted by feedback control to maintain a speed ratio. This feedback control has been implemented, for the first time, in an existing simulation that predicts the dynamic behavior of a metal V-belt using explicit structural analysis. The new simulation enables stable control of a target speed ratio when appropriate gains are set for each analysis condition.

Infinitely variable transmission (IVT) is one of the methods used to extend the ratio coverage. In this paper, a dynamic behavior analysis technology was developed for an IVT utilizing a half-toroidal variator as the shifting device. The traction coefficient of traction fluid used for the half-toroidal IVT varies greatly according to contact surface slip rate, contact pressure and fluid temperature. This paper used measurement values from a four-roller machine to identify the coefficient, and then applied it to the dynamic behavior analysis. Use of the identified traction coefficient enabled power transmission characteristic predictions of a half-toroidal variator. To reproduce the elastic deformation in actual operation, the research used the Finite Element Method (FEM) for modeling. This model was also used to visualize the frictional state of traction surfaces during operation.

This paper relates a method for seeking Pareto solutions for strength, torque-rotational speed characteristics, losses, and exciting force in the preliminary design of interior permanent magnet synchronous motors (IPMSM) and carrying out optimal design in an integrated manner. As to the constraint on strength, it was determined that the von Mises stress on the rotor core with respect to the load of the centrifugal force at 1.2 times the maximum rotational speed should not exceed the breaking strength of common electrical steel sheet material. As to the torque-rotational speed characteristic, this was determined to be the maximum torque for each rotational speed, taking into account the maximum voltage and current input when maximum torque per ampere control and field weakening control are applied. The maximum torque at low rotational speed and the maximum power at maximum rotational speed were taken as evaluation parameters.

To increase the durability of multiple-plate clutches used in automatic transmissions, attention was focused on the wear history of the facing material. Measurements have confirmed that correlations can be observed between initial wear and disk contact pressure when the clutch is engaged, and between steady wear and plate temperature. Next, simulation technology was developed to quantify the disk contact pressure and plate temperature. When simulated contact pressure distribution and temperature distribution were used to establish correlations with durability wear, good proportional relationships were found in both cases. It was also found that when clutch specifications and driving conditions were varied, the gradient of the correction also varied, but the correlation remained proportional as long as the same facing material was used. The gradient was ranked as a wear property specific to the facing material.

In designing CVT pulleys, the effect of the fit clearance of the movable pulleys and their stiffness on the transmission efficiency and strength of the metal pushing V-belt is not necessarily clear. The research discussed in this paper introduced a pulley model that defined the pulleys as elastic bodies to a previously developed technology for the prediction of the transmission efficiency of the belts. As a result, it was found that when the fit clearance is reduced, the transmission efficiency of the belt is increased, and the amplitude of stress on the innermost rings and the element neck section is reduced. In addition, it was found that if pulley stiffness was reduced transmission efficiency was also reduced, and the amplitude of stress on the element neck section increased. This indicated that the fit clearance and the pulley stiffness changed the degree of deflection of the pulleys in the axial direction.

The project discussed in this paper focused on the torque transmission characteristics of facing materials in order to enable desktop prediction of the torque capacity of the multiple plate clutches used in automatic transmissions (AT). The amount of torque transmitted by the facing materials themselves is affected by the temperature, contact pressure and sliding velocity of the friction surfaces. An analytic model of a test apparatus was therefore constructed, and the friction properties of the facing material were identified from the amount of torque transmitted. Next, a torque capacity prediction model, able to simulate the flow of torque transmission in the transmission, was constructed. This enabled torque capacity in an operating AT to be predicted for the first time with an accuracy to within ±5% of measured values.

When a vehicle is cruising, unpleasant noise in the 4 to 5 KHz high-frequency band can be heard at the center of all seats in the vehicle cabin. In order to specify the source of this noise, the correlation between the noise and airborne noise from the outer surface of the transmission was determined, and transfer path analysis was conducted for the interior of the transmission. The results indicated that the source of the noise was the 0th-order breathing mode specific to the drive motor. To make it possible to predict this at the desk, a vibrational analysis method was proposed for drive motors made up of laminated electrical steel sheets and segment-type coils. Material properties data for the electrical steel sheets and coils was employed in the drive motor vibrational analysis model without change. The shapes of the laminated electrical steel sheets and coils were also accurately modeled.