JPS6196253A - V-belt type automatic speed change gear - Google Patents

Abstract

PURPOSE:To reduce load exerted to a belt upon low speed operation, by providing a clutch which is engaged and disengaged in association with the movement of a movable face in a drive pulley, on the back surface of the movable face, and by coupling the driven side of the clutch with the shaft of a driven pulley through a chain. CONSTITUTION:A clutch 8 which is engaged and disengaged in assoaciation with the axial movement of a movable face is provided on the rear surface of the movable face in a drive pulley in a V-belt type automatic speed change gear 3. Meanwhile this drive side of this clutch is directly coupled to a driven pulley shaft 9 through a chain 16. Accordingly, when the diameter of the drive pulley becomes less so that the movable face is displaced rightward as upon low speed operation, the drive torque is transmitted to the driven side through the clutch and chain, and therefore, the load exerted to the belt may be reduced.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a V-belt automatic transmission.

[Prior Art] Some small motorcycles are designed to automatically shift gears using a V-belt. In such small motorcycles, such as scooters, a drive pulley consisting of a fixed face and a movable face is installed on the crankshaft, and a driven pulley consisting of a fixed face and a movable face is also installed on the driven shaft. There is. In such small motorcycles, the rotation radius of the V-belt wrapped around these pulleys is continuously changed according to the number of revolutions of the crankshaft, thereby changing the speed of the crankshaft power and transmitting it to the driven shaft. I am trying to communicate this to the public.

By the way, in such a V-belt type automatic transmission, during low speed rotation, the distance between the movable face of the drive pulley and the fixed face is wider than the distance between the movable face and the fixed face of the driven pulley. Regarding the contact area between the V belt and each pulley, the contact area between the V belt and the drive pulley on the crankshaft is smaller than the contact area between the V belt and the driven pulley on one driven shaft.

Therefore, in conventional V-belt type automatic transmissions, during low-speed rotation, the drive pulley side of the crankshaft receives a large load per unit area, so there is a risk that the durability of the V-belt may be impaired due to long periods of climbing, etc. there were.

(Objective of the Invention 1) In view of the above-mentioned circumstances, an object of the present invention is to provide a V-belt type automatic transmission in which the durability of the V-belt is improved.

[, Structure of the invention]

In order to achieve the above object, the present invention disposes a linking means such as a chain in addition to the V-belt between the crankshaft and the driven shaft. is transmitted to the driven shaft by this linking means for both the V-belt and the J-belt.

Embodiment] The present invention will be described below with reference to an embodiment shown in the drawings.

The drawings show an embodiment of a V-belt type automatic transmission according to the present invention. With this V-belt automatic transmission,
Crankshaft 1, guide plate 2 and drive pulley 3
A fixed face 4 is fixedly installed. The guide plate 2 has 1! A movable face 5 of the live boob 93 is supported movably in the axial direction of the crankshaft 1 by a spline, and a centrifugal roller 6 is housed between the movable face 5 and the guide plate 2. Furthermore, a sprocket 7 is loosely fitted to the crankshaft 1 on the side of the movable face 5 of the drive pulley 3, and a friction clutch 8 is interposed between the sprocket 7 and the movable face 5.

This friction clutch 8 maintains a connected state during low speed rotation when the movable face 5 of the drive pulley 3 is positioned outward.

On the other hand, a fixed face 11 and a movable face 12 of a driven pulley 10 are rotatably supported on the driven shaft 9, and a centrifugal clutch 1 is connected between the driven shaft 9 and the driven pulley 10.
3 is interposed. Furthermore, a sprocket 14 is integrally fixed to the side end of the fixed face 11 of the driven pulley 10.

Between the crankshaft 1 and the driven shaft 9, a V-belt 15 is wound between the respective boots IJ 3 and 19, and a ζ chain 16 is wound between the sprockets IJ 3 and 19.

The operation of the above-described power transmission device will be explained below.

In the idling rotation range of the crankshaft 1, the movable face 5 of the drive pulley 3 is located at the right end of the guide plate 2 in the figure, and the clutch 8 is in the engaged state. Therefore, the power of the crankshaft 1 is transmitted to the driven pulley 10 via the V-belt 15 and also to the driven pulley 10 via the chain 16 and sprocket 14.

However, in such an idling rotation range of the rank shaft 1, the centrifugal clutch 13 is in a disengaged state, and the power of the driven pulley 10 is not transmitted to the driven shaft 9. When the rotation of the crankshaft 1 leaves the idling rotation range and reaches the low speed rotation range, the centrifugal clutch 13 becomes engaged, and the power of the crankshaft 1 is thereby transmitted to the driven shaft 9 via the V-belt 15 and the chain 16. be done.

Furthermore, when the rotational speed of the crankshaft 1 increases and reaches a medium speed rotation range, the centrifugal force of the centrifugal roller 6 increases and the clutch 8 becomes disengaged, so the transmission of power by the chain 16 is cut off and the crankshaft The power of the shaft 1 is transmitted to the driven shaft 9 only by the V-belt 15.

In the above embodiment, the rotating body is the sprocket 7.
14 is adopted, and a chain 16 is adopted as a linking means for these rotating bodies, thereby transmitting the power of the crankshaft 1 to the driven shaft 9 along with the V-belt 15 in the low speed rotation range.7. 14 and chain 1
Of course, the power transmission by 6 may be configured by a combination of gears and timing belts or only gears.

However, in any case, it goes without saying that the reduction ratios of the V-belt 15 and other linking means need to be matched.

[Effects of the invention] As explained above, in the V-belt automatic transmission according to the present invention, during low-speed rotation, which places a particular burden on the V-belt,
Since the power of the crankshaft is transmitted together with the V-belt to the driven shaft through a rotating body such as a sprocket and a linkage means such as a chain, the durability of the V-belt can be improved.

[Brief explanation of the drawing]

The drawing is a sectional view of essential parts showing an embodiment of a V-belt type automatic transmission according to the present invention. 1 Crankshaft, 3...Drive pulley, 4 Fixed face, 5 Movable face, 7 Sprocket, 8 Clutch, 9 Driven shaft, 1o Driven pulley, 11 Fixed face, 12 Movable face, 14 Sprocket I.
,] 5-V-belt, 16-chain.

Claims (1)

[Claims] A V-belt is wound between a drive pulley interposed on the crankshaft and a driven pulley interposed on the driven shaft, and the movable face of each pulley is moved according to the rotation speed of the crankshaft. In a V-belt type automatic transmission that changes the speed of the power of the crankshaft and transmits it to the driven shaft by changing the rotation radius, a rotating body is loosely fitted to the crankshaft and rotates on the fixed face of the driven pulley. The rotating body is fixedly installed, and these rotating bodies are linked to each other by a linking means, and a clutch is provided between the movable face of the drive pulley interposed on the crankshaft and the rotating body loosely fitted on the crankshaft. is used to maintain the clutch in a connected state in the low-speed rotation range of the crankshaft, and when the rotation of the crankshaft reaches medium speed or higher, the movable face of the drive-side pulley moves to maintain the clutch in a connected state. A V-belt type automatic transmission characterized by a clutch being in a disengaged state.