JP2007146987A - Pulley of belt type continuously variable transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a belt type continuously variable transmission capable of increasing friction force on a contact face of a pulley with a belt and preventing occurrence of slip even at start time and at load fluctuation time to transmit gear shift power accurately. <P>SOLUTION: A plurality of recessed faces and projecting faces are provided alternately and radially from the center on a conical surface of the pulley, and the recessed faces and the projecting faces of a pair of pulleys are asymmetrically combined. Distance between facing faces of the recessed faces and the projecting faces on the same circumference is made same everywhere over 360°, and a V belt wrapped around the pair of pulleys is made zigzag. The force by which the belt tends to elongate generates high pressure on the projecting face by increase of area of the contact face of the pulley with the V belt and tensile force acting on the V belt to prevent slip. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a pulley for preventing slippage of a belt type continuously variable transmission.

  A belt-type continuously variable transmission in which a V belt is wound between two sets of pulleys to give an appropriate tension to the belt and power is transmitted by the frictional force of the contact surface has been put into practical use. However, the practical belt-type continuously variable transmission has a drawback that when the load fluctuates at the time of starting or during power transmission, slip occurs on the contact surface between the belt and the pulley and the transmission power cannot be accurately transmitted.

As a measure for improvement, there is a method of improving the friction characteristics by providing a specific surface roughness on the pulley surface, or providing ridges on the radial or circumference. However, this method can damage the belt unless there is no slip.
JP 2002-213580 A

  The problem to be solved is that the frictional force cannot be increased on a limited flat surface.

  A plurality of concave and convex surfaces that radiate from the center of the cone are alternately divided equally on the belt contact cone surface of the pulley to form a smooth wave shape, and the concave and convex surfaces of the paired pulleys are arranged asymmetrically to form the same circle. The distance between the concave and convex surfaces facing each other around the circumference is the same at 360 °.

  The contact area between the pulley and the belt increases, the tension that acts on the belt during startup and load fluctuations increases, and the force that the belt tries to stretch generates high surface pressure on the convex surface. To prevent.

  The object of obtaining a high frictional force while maintaining the form of a known belt type continuously variable transmission was realized by forming a concave surface and a convex surface on the conical surface of the pulley.

  FIG. 1 shows an example of the structure of a known belt-type continuously variable transmission. An input shaft 2 and an output shaft 3 are provided in a transmission case 1, and a pair of pulleys 4, 5 and 6, 7 are provided on each shaft. Maintaining the conical angle θ facing each other, they are engaged with the keys 15 on the shaft, each one is fixed to the shaft, and one is slidably assembled on the shaft. A belt 8 is wound between two sets of pulleys to give an appropriate tension. The pulleys on both shafts are assembled in the opposite direction of the fixed side and the movable side, the pulleys on the movable side are connected to the levers 9 and 11 and the connecting rod 10 is further provided. When the left and right sides are operated, the movable pulleys 5 and 7 move in the same direction on the shaft, one of the pulleys reduces the facing distance, and the other pulley is moved away to change the pitch diameter at which the pulley and the belt are engaged. That is, shifting is performed by changing the pitch diameters in opposite directions such that the diameter of one pulley increases and the other pulley decreases. The connecting rod 10 has a function of a tongue buckle and can apply tension to the belt.

  In FIG. 2, a plurality of concave surfaces 12 and 13 each having a concave surface angle θ1, a depth of convex surface angle θ2, and a convex surface angle θ2 having the same angle from the central point 16 of the cone are radially formed on the conical surface formed by the cone angle θ of the pulley. It is the figure which showed the state which arranged alternately equally and formed the concave surface and the convex surface on the smooth wave.

  Similarly, in FIG. 2, the concave and convex surfaces of the pair of pulleys face each other asymmetrically, the distance between the concave and convex surfaces on the same circumference is the same at 360 °, and the belt is in a zigzag state.

It is explanatory drawing which showed the internal structural example of the belt-type continuously variable transmission. It is explanatory drawing which showed the detail of the pulley and the winding state of the belt.

Explanation of symbols

1 Transmission case
2 Input shaft 3 Output shaft 4 Pulley (fixed side)
5 Pulley (movable side)
6 Pulley (fixed side)
7 Pulley (movable side)
8 Belt 9 Lever
10 Connecting rod (Tunbuckle)
11 Lever
12 Concave
13 Convex surface
14 Control lever
15 keys
16 Cone center point θ Cone angle θ1 Concave surface angle θ2 Convex surface angle

Claims (1)

In a belt-type continuously variable transmission, a plurality of concave and convex surfaces having the same angle depth from the center of the cone are arranged alternately and equally radially on the conical surface of the pulley, and the concave and convex surfaces are formed into a smooth wave shape. The belt-type continuously variable transmission is characterized in that the distance between the concave and convex surfaces of the pair of pulleys is asymmetrically combined with each other, and the distance between the concave and convex surfaces on the same circumference of the pulleys is 360 ° everywhere. pulley.

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