GB2180617A

GB2180617A - Chain for continuously variable cone-pulley belt-drive transmissions

Info

Publication number: GB2180617A
Application number: GB08609560A
Authority: GB
Inventors: Ernst Kohl
Original assignee: Ford Motor Co
Current assignee: Ford Motor Co
Priority date: 1985-09-21
Filing date: 1986-04-18
Publication date: 1987-04-01
Also published as: FR2587777A1; FR2587777B1; GB2180617B; DE3533778C1; GB8609560D0

Abstract

A chain for continuously variable cone-pulley belt-drive transmissions comprises a plurality of trapezoidal plates 1,1' arranged in close succession and which are held together by means of tie elements so as to form an endless driving strand. Each plate 1,1' is formed with four holes lying on a line parallel to and substantially mid-way between the parallel sides of the trapezium, the two inner holes receiving two respective link pins 2, which connect the plate 1,1', to one of the two adjacent plates 1',1 of the chain and the outer two holes receiving two further respective link pins 3 connecting the plate 1,1' to the other of the two adjacent plates 1',1 of the chain. <IMAGE>

Description

SPECIFICATION Chain for continuously variable cone-pulley beltdrive transmissions The invention rel ates to a chai n for conti nuously vari- able cone-pulley belt-drive transmissions.

An open-linkchainforcontinuouslyvariable conepulley belt-drive transmissions comprising a plura lity oftrapezoidal plates arranged in close succession and held together by way of tie elements so as to form an endless driving strand, is known from US P3 949621. To permit the chain of this patent to bend around the cone-pulleys, the plates are either held at a slightdistancefrom oneanotheror, if the plates taper in thickness at the narrower side of the trapezium, they may be held in contact with one another.

Steel bands disposed in lateral slots in the trapezo- idal plates are provided as the tie elements.

These known open-linkchains have the disadvant- agethatthe endless steel bands are difficultto control in terms of their tolerance, in particular in their multiple-layer arrangements, and irregularfrictional contact with the endless steel bands occurs in the lateral slots in the trapezoidal plate members, as a resuIt of which the latter are subject to premature wear and breakdown.

A number of designs of chains formed of pivoted links having flat inclined portions for engaging the cone-pulleys of continuously variable belt-drive transmissions are also already known, but they generally have the disadvantage, as compared with the open-link chains, there are substantial distances between the points of contact with the cone-pulleys, as a result ofwhich, owing to their abrupt meeting when entering the cone-pulleys, they cause a rough running action, which leads to increased noise and greaterwearofthe running pair.

The present invention seeks to provide an improved open-linkchainforcontinuouslyvariable cone-pulley belt-drive transmissions in which the problems oftolerance and wearofthe endless steel band may be mitigated.

According to the present invention, there is provided a chain for continuouslyvariable cone-pulley belt-drive transmissions, comprising a plurality of trapezoidal plates arranged in close succession and which are held together by means tie elements so as to form an endless driving strand, wherein each plate is formed with four holes lying on a line parallel to and substantially mid-way between the parallel sides ofthetrapezium,thetwoinnerholesreceivingtwo respective linkpinswhich connectthe plate to one of the two adjacent plates ofthe chain and the outertwo holes receiving two further respective link pins connecting the plate to the other ofthe two adjacent plates ofthe chain.

The link pins which in the present invention serve totietogetherthetrapezoidal plates are of simple construction enabling them to be manufactured in large quantities with the necessary tolerances.

Preferably, the heads of the link pins are partspherical and are received in complementarily shaped recesses in the plates to permitthe link pins to pivot relative to the planes ofthe plates.

The invention will now be described further, by way of example, with reference to the accompanying drawings, in which: Figure 1 is an elevation of a trapezoidal plate of an open-link chain according to the invention which has been separated at one point; Figure2 is a sideviewof part ofthe open-linkchain according to Figure 1; Figure 3 is a plan view of part ofthe open-link chain according to Figure 1; Figure 4 is a section along the line IV-IV in Figure 1 through two adjacent trapezoidal plate members with the link pins indicated in one half; Figures 5a, 5b, 5c and 5dshow alternative constructions ofthe link pins; Figure 6is an enlarged view of some plates in their position when travelling around the cone pulleys;; Figure 7shows an end linkforclosing the open-link chain, and Figure 8 is a perspective view of the open-link chain immediately before fitting the end link.

As shown in Figures 1 to3, an open-linkchain according to the invention comprises a pluralityofsuc- cessivetrapezoidal plates 1 and 1',which are disposed a slight distance apart. The plates may touch one another if their narrower sides are tapered in thickness, in orderto enable the chain formed ofthe plates to bend around the cone pulleys. The plates rejoined to one another by pairs of link pins 2 and 3.

As shown in Figure 4 in particular, each trapezoidal plate 1 and 1' comprisesfourholes4and 5 re spectivelywhich are arranged at regular intervals across the width of the trapezium and lie on a line midway between and parallel to the parallel sides ofthe trapezium. The outer holes are formed on one side of each plate with ball-cup recesses while the inner holes areformed with similar recesses button the otherside ofthe plate.

The link pins 2 and 3 each comprise a first head 11, a shank 1 2 and a second head 13. Thefaces ofthe heads 11 and 13 which contactthe plates are part- spherical to form, in conjunction with the ball-cup recesses, ball joints which permit the pins to pivot relative to the planes of the plates.

As shown in Figures 5a to 5d, the link pins, each comprise a shank formed integrallywith one head while the other head 13 is formed in one offour alternative ways.

In Figure 5a the shank 12' is secured to the head 13' by form locking engagement, in this case a screw. In Figure 5b, the shank 12" is soldered to the head 13".

In Figure 5e the shank 12"' is welded to the head 13"' and in Figure 5d the second head 13 is formed integr allywiththeshankascan bethecasefortheend link described below with particular reference to Figure 7.

In the sectional view taken along the line VI-VI in Figure 3 and shown to an enlarged scale in Figure 6, the cooperation of the link pins 2 and 3 with the re spectivetrapezoidal plates 1 and 1' is shown in the region ofthe bend ofthe open-linkchain on thecone- pulley. It should be mentioned that the bores in the trapezoidal plate members receiving the link pins must have sufficient play to permit the pivotal move mentofthe individual plates.

The end link 15 shown in Figure 7 is provided, in the same way as the other plate members, with four boresforthe link pins 2 and 3 arranged in pairs, but it is divided along a horizontal separation plane 16 into a lowerpart 17 and an upperpart 18.Thetwo parts 17 and 18 are provided with bores 19 which extend at right angles to the separation plate 16 and which when designed as blind-end bores are used for weld- ing thetwo parts 17 and 18 in thethermitewelding process, while when designed as through bores the two parts 17 and 18 can be joined to one another by screw fastening or rivetting.

The working strand immediately before the fitting of the end link 15 is illustrated in the perspective view shown in Figure 8.

Claims

1. Achainforcontinuouslyvariablecone-pulley belt-drive transmissions, comprising a plurality of trapezoidal plates arranged in close succession and which are held together by meanstie elements so as to form an endless driving strand, wherein each plate is formed with four holes lying on a line parallel to and substantially mid-way between the parallel sides ofthe trapezium, the two inner holes receiving two respective link pins which connectthe plate to one of the two adjacent plates ofthe chain and the outertwo holes receiving two further respective link pins connecting the plate to the other of the two adjacent plates of the chain.

2. AchainaccordingtoClaim 1,whereinthe heads of the link pins are part-spherical and are received in complementarily shaped recesses in the plates to permitthe link pins to pivot relative to the planes of the plates.

3. Achain as claimed in claim 1 or2,whereinthe length of the pins affords a space between adjacent trapezoidal plates.

4. A chain as claimed in claim 1 or 2, wherein the trapezoidal plates taper in thickness towardsthe narrower of the parallel sides of the trapezium and the link pins serve to hold the plates in contact with one another.

5. A chain as claimed in any preceding claim, wherein the links comprise separately formed heads and shanks secured to one another by soldering, welding or form locking engagement.

6. A chain as claimed in any preceding claim, wherein an end link is provided for securing the ends ofthe endless chain to one another, the end link being formed in two parts which are joined to one another along a line passing through the holes four the link pins.

7. A chain for continuously variable cone-pulley beit-drivetransmissions,constructed and adapted to operate substantially as herein described with reference to and as illustrated in the accompanying drawings.