Endless belt power transmission systems or components – Pulley with belt-receiving groove formed by drive faces on... – Fluid pressure actuator for adjustment of member
Reexamination Certificate
2000-11-09
2002-12-17
Bucci, David A. (Department: 3682)
Endless belt power transmission systems or components
Pulley with belt-receiving groove formed by drive faces on...
Fluid pressure actuator for adjustment of member
C474S018000
Reexamination Certificate
active
06494798
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a pulley press controlling apparatus using an elastic member in which a pressurizing force and an elastic force corresponding thereto are always simultaneously applied from outside to a frictional transmission surface between a pulley and a belt transmission in a continuously variable speed transmission or a constant speed ratio transmission to stably maintain the accuracy of the elastic press and so on over a long period of time.
The idea for directly and hydraulically supplying and controlling an external pressurizing force to a secondary pulley having a belt transmission member held between two disks is well-known from, for example, such as Japanese Patent Application Laid-Open No. Hei 9 (1997)-217819 or U.S. Pat. No. 5,180,339. The greatest feature of prior art of this kind lies in that a hydraulic pressurizing device and an elastic member are pressed and disposed in parallel to each other with respect to a secondary pulley disk to be pressed. That is, because of the parallel disposition, respective pressurizing means directly press the secondary pulley independently. This has a decisive defect with respect to the frictional transmission for the following reason. That is, the horse power P fed by the pulley to the load is normally expressed by the following equation between the revolution number N and the torque T:
P[W]
=1.027×
N[
rpm]
×T[
kgm] (1)
Accordingly, it is necessary for the transmission of a fixed horse power P
c
to reduce a torque T of a belt when the revolution number N increases, and conversely increase the torque T when the revolution number N reduces. In the prior art, inverse proportional pressure is applied to the secondary pulley by a hydraulic pressurizing device, but since there is present no elastic force in fluid pressure itself, in control of internal pressure of a hydraulic valve, an elastic member is used to suppress the disturbance of internal pressure generated every change-over or switching.
Then, the using state of the elastic member will be mentioned referring to FIG.
6
. Even if the hydraulic pressurizing device should realize the inverse characteristic A between the pressurizing force to the secondary pulley and the revolution number, the elastic force of the elastic member merely comprises the direct proportional characteristic D. Accordingly, this means that the elastic force is applied to the pressurizing force merely by a point of intersection F between the characteristics A and D, but in points other than the point of intersection F, the elastic force rarely contributes to transmission. The fact that the elastic force is not present in the frictional transmission surface despite the presence or absence of variable speed indicates that the momentary return into the stable transmission caused by the self settling function for pressurizing and absorbing shock vibrations between the pulley and the belt and the automatic aligning function fails to be achieved. Therefore, since in the frictional transmission surface, the state of surplus press or lack in press is repeated every disturbance, there poses a disadvantage that consumption of the frictional surface is accelerated, resulting in disablement of transmission in a short period of time.
The present applicant has made a proposal, in Japanese Patent Application No. Hei 10 (1998)-321246, in which an elastic pressurizing force generated by pressurizing a compression device and an elastic device in series with each other is applied to a secondary pulley. However, positive application of the elastic force of the elastic member to the friction transmission causes an advantage and a disadvantage present simultaneously. The advantage includes stabilization of transmission for a long period of time, and high-speed control responsiveness. The disadvantage includes a huge dimension of and a large-size of the elastic member, disturbance of process accuracy in manufacture of compression displacement to pressurizing force, variation of pressurizing characteristic caused by deformation and deterioration in order to maintain repeated compression and high load compression, and ambient temperature. The huge dimension can be solved by measures such as the use of a special high load elastic member or the arrangement of the elastic member in a non-rotational state, but the disturbance of the elastic pressurizing force generated from the pressurizing device itself brings forth instability of direct frictional transmission and degeneration of efficiency. Accordingly, it has been strongly expected that the pressurizing force and the revolution number are applied to the elastic pressurizing device having the elastic member and the non-elastic pressurizing device using the negative measures for applying restoring compensation of an error in pressurizing force caused by manufacturing or use of high load and already generated to a proper value, and the positive measures for applying function adjustment for further accelerating and strengthening utility of an elastic member during transmission or during stoppage.
SUMMARY OF THE INVENTION
A fundamental solution of the present invention is to provide a pulley press controlling apparatus using an elastic member in which a pressurizing device always applies an elastic pressurizing force to a pulley, and always controls it to a predetermined desired pressurizing force selected value with the compensation of an error in pressurizing force of the elastic pressurizing force and/or the adjustment of pressurizing function to stably maintain and strengthen the utility function of the elastic pressurizing force of the elastic member in a long period of time.
According to a first aspect of the present invention, an error in pressure of an elastic pressurizing force caused by the manufacturing and processing accuracy of a pressurizing device having an elastic member and the peripheral temperature of installation and caused by the deformation and deterioration of the elastic member under the repeated compression or high compression for a long period of time is restored and compensated to always apply an elastic pressurizing force of high accuracy.
According to a second aspect of the present invention, a desired selected value of an elastic pressurizing force applied by an elastic member is applied with fine adjustment during transmission operation to forcibly change the efficiency of transmission or safety rate, or applied with extremely low reduction adjustment positively during stoppage of transmission to forcibly release or suppress the compression state for a long period of time to thereby apply strengthening adjustment of utility function of the elastic member substantially.
According to a third aspect of the present invention, restoring compensation of an error in pressure of an elastic pressurizing force and adjustment for strengthening a pressurizing force by forcibly reducing the pressurizing force selected value are combined so that operating information of restoring compensation is taken in at the time of the strengthening adjusting operation in the process of applying pressure to or releasing pressure from the elastic member to effect operation processing to newly execute pressure error compensation for variable speed or press control.
According to a fourth aspect of the present invention, when a pressurizing device operates in variable speed a pulley under non-elastic pressurizing force, an error in revolution number of a secondary pulley caused by a deformation and deterioration of belt dimension is compensated by the procedure similar to that taken for the error in pressurizing force.
According to a fifth aspect of the present invention, since a pulley added an elastic force controls an output torque based on a belt frictional force and a pulley added a non-elastic force controls an output revolution number, a control device provides operating instructions to the operating devices by dealing with various informations collectively and so simplic
Bucci David A.
McAnulty Timothy
Rothwell Figg Ernst & Manbeck
Tokyo Automatic Machinery Co., Ltd.
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