Honda Giken Kogyo Kabushiki Kaisha

Honda Motor Co., Ltd.

Hirofumi Akagi

Takamichi Shimada

Hideaki Yoshida

Shigeru Kanehara

Toru Yagasaki

Hideaki Aoyama

Kouhei Ohsono

Atsushi Sato

Ken Kanokogi

Akihito Ohhashi

Tooru Yagasaki

Tooru Fujii

Shinya Kuwabara

A shift control apparatus for a vehicle which has an engine with an exhaust supercharger, and a transmission, if there is a deceleration intention of a driver, compares a target torque and an actual torque, and while the actual torque is higher than the target torque and a difference therebetween is greater than or equal to a predetermined threshold value, controls a speed at which to cause a gear ratio of the transmission to change to the target gear ratio to be slower than at a time of normal shift control.

Shift control apparatus and shift control method

In a belt for a continuously variable transmission, a first clearance CL is defined between a projection and a recess formed on front and rear surfaces of a metal element, and a second clearance CLy is defined between an upper surface of a metal ring assembly and a lower ear surface of the metal element. By setting a relation, CLY>CL ensures, that when the metal element has been pitched, the projection and the recess can be first brought into contact with each other, thereby preventing a reduction in durability of the metal ring assembly. If the thickness of the metal ring assembly is represented by T , and the vertical opening of the ring slot is represented by D, when the value of D/T exceeds 11/8, the power transmitting efficiency is reduced. Therefore, the reduction in power transmitting efficiency can be prevented while maintaining durability of metal ring assembly by setting D/T at a smaller value than 11/8.

Belt for non-stage transmissions

A belt for a continuously variable transmission includes a metal ring assembly formed of a plurality of endless metal rings laminated one on another, and a large number of metal elements each having a ring slot into which the metal ring assembly is fitted. In the belt, a crowning radius of the metal ring in a free state is set smaller than a crowning radius of a saddle face of the ring slot supporting the innermost metal ring. Thus, the metal ring assembly can be centered to a central portion of the saddle face, whereby a difference between a tensile stress at a central portion of an outer peripheral surface of the metal ring and a tensile stress at opposite ends of the outer peripheral surface can be reduced in an area where the metal belt is wound around a pulley, thereby preventing a reduction in durability.

Belt for continuously variable transmission

A belt for continuously variable transmission, wherein the relationship between the thickness of the metal ring assembly and the groove width of the ring slot is established so that a limit rolling angle &agr; defined as a rolling angle of the metal elements provided when a radially outer peripheral surface of the metal ring assembly contacts a radially outer edge of the ring slot in the metal element is in a range of 0.7&deg;<&agr;<2.5&deg;. The upper limit value 2.5&deg; of the angle &agr; is set as a rolling angle at which the driving force transmitting efficiency is a predetermined value or more, and the lower limit value 0.7&deg; of the angle &agr; is set as a rolling angle generated following the deformation of a V-face due to an axial thrust on a drive or driven pulley.

The durability of the entire metal ring assembly is enhanced by increasing the wear life of the radially inner surface of the metal ring of the innermost layer which is the layer which is most easily fractured. A belt for a continuously variable transmission is formed by supporting a large number of metal elements on a metal ring assembly wherein multiple sheets of endless metal rings are layered. The thickness of the metal ring of the innermost layer is different from the thickness of the metal rings of layers other than the innermost layer. The thickness of the metal ring of the innermost layer is set so that the stress amplitude applied to the radially outer surface of the metal ring of the innermost layer is not more than the stress amplitude applied to the radially outer surfaces of the metal rings of layers other than the innermost layer. By setting the thickness of the metal ring of the innermost layer at 0.042 mm to 0.161 mm when the thickness of the metal rings of layers other than the innermost layer is 0.185 mm, the stress amplitude &sgr;a,applied to the metal ring of the innermost layer becomes lower than the stress amplitude &sgr;a,of 25.65 kgf/- mm,applied to the other metal rings. Thus the durability of the metal ring of the innermost layer can be enhanced to increase the life span of the entire metal ring assembly.

A belt for a continuously variable transmission in which an aggregate of metal rings formed by laminating a plurality of pieces of endless metal rings support a plurality of metal blocks. When the ratio .xi. of the coefficient of friction is set to be 2.0&gt;.xi.&gt;0.65, the amount of change in the tension on the metal ring of the innermost position decreases correspondingly. In particular, when the ratio .xi. of the coefficient of friction is set to be 1.0, resulting in the coefficient of friction .mu..sub.s between a ring and a block being equal to the coefficient of friction .mu..sub.SS between a ring and a ring, the amount of change in the tension on all metal rings become uniform, and each metal ring shares an amount of change in the tension which is 8% of the entire amount. This makes it possible to decrease the amount of change in the tension on the metal ring of the innermost position and, hence, to increase the durability of the aggregate of metal rings as a whole.

Belt for a continuously variable transmission

A metal V-belt type continuously variable transmission in which the length of a side of an element contacting with a V-face of a pulley is shortened to increase a ratio range. If the element side length of a metal element is represented by L, the angle of the V-face of the pulley is represented by .alpha., and the hertz surface pressure between the pulley and the metal element is represented by .sigma..sub.H, the following relation is established: L .varies. sin .alpha./.sigma..sub.H.sup.2. When the hertz surface pressure .sigma..sub.H is determined to be between an upper limit value defined by the wear durability of the metal element and a lower limit value defined by the limit tensile force of an endless belt, the element side length L can be decreased by decreasing the angle of the V-face of the pulley. Thus, the distance through which the metal element can be moved radially of the pulley is increased to increase the ratio range.

Metal V-belt type continuously variable transmission

In a metal V-belt type continuously variable transmission having a driving pulley and a driven pulley, the inclination angle .alpha. of a V-groove in the pulleys is set in a range represented by tan.sup.-1 .mu.a&lt;.alpha.&lt;tan.sup.-1 .mu.s, wherein .mu.s represents the static friction coefficient between the pulley and an endless belt, and .mu.a represents the dynamic friction coefficient between the pulley and the endless belt. In a conventional metal V-belt type continuously variable transmission, the inclination angle .alpha. is set in a range represented by .alpha.&gt;tan.sup.-1 .mu.s. If the transmittable torque Tin is increased, the tensile force of the endless belt is increased to produce slipping between the endless belt and the pulley. However, according to the present invention, by decreasing the inclination angle .alpha. to reduce the tensile force of the endless belt, the transmittable torque Tin can be increased while preventing slipping of the endless belt.

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Wako, Japan

Hirofumi Akagi