GB2327735A

GB2327735A - Transmission chain, especially a timing chain for an internal combustion engine

Info

Publication number: GB2327735A
Application number: GB9816200A
Authority: GB
Inventors: Jean-Louis Albertin
Original assignee: Sachs Industries SA
Current assignee: Sachs Industries SA
Priority date: 1997-07-28
Filing date: 1998-07-27
Publication date: 1999-02-03
Anticipated expiration: 2018-07-27
Also published as: GB9816200D0; FR2766540A1; GB2327735B; DE19833576A1; DE19833576B4; FR2766540B1

Abstract

Transmission chain is composed of links having internal and external plates connected by pin, characterised in that the plates 21,22 of the internal links are provided with collars 211, 212, 221, 222 facing the inside and forming the bearings of the articulation pins 3 between the internal links 2 and the external links 1. As shown the each pin is provided with a shoulder 31. Alternatively the pin may be provided with a roller (31A, Fig 4) through which the pin extends. In a further embodiment the ends of a roller (31B, Fig 5) coaxial with the pin 3 accommodate the collars 211,221.

Description

The present invention relates to a transmission chain, such as a chain of an internal combustion engine, for engine timing, driving the oil pump and balancing the camshafts, which chain is composed of links having internal and external plates connected by pins.

Transmission chains, especially those with which the engine timing system of internal combustion engines are equipped, constitute vital elements of an engine. In some cases, especially where diesel engines are concerned, the transmission is an essential element because any breakage causes the distribution pump to fail and the engine to be destroyed almost immediately.

The aim of the present invention is to provide a chain which is easy to manufacture, completely supple in the region of the articulations between the links, permits the transmission of large forces and of which the lubrication of the contact regions is improved.

To that end, the invention relates to a transmission chain of the type defined above, characterised in that the plates of the internal links are provided with collars facing the inside and forming the bearings of the articulation pins between the internal links and the external links.

The chain according to the invention is composed of a reduced number of components. The collar formed in the plates of the internal links enables the sleeve acting as a passage for the pin and the operations associated with the assembly of the sleeve and the plates of the internal links to be dispensed with.

The collars provide sufficient play to permit good pivoting of the external link relative to the internal link and an improved lubrication of the regions of contact between the pin and the collars owing to better penetration of the oil due to the play between the collars and the pin.

In a particularly simple manner, the collars are produced by stamping from the plates.

The production of the collars by stamping constitutes an accurate and simple manufacture compatible with the desired aim, namely a chain that is technically efficient and inexpensive.

According to other advantageous features of the invention, the pin is provided with a shoulder occupying the gap between the edges of the collars.

The shoulder carried by the pin constitutes an element for spacing the plates owing to the support which it provides for the collars. That support permits and facilitates the lubrication of the articulation. The shoulder also constitutes the contact element of the chain and the teeth of the pinions cooperating with the chain. The force is thus transmitted directly from the pinion to the plates of the chain without the interposition of a sleeve as in the prior art.

According to another advantageous feature of the invention, the collars are kept spaced apart by a roller which occupies the gap between the collars and through which the pin extends.

According to another advantageous feature, the pin is provided with a roller through which the pin extends and which is arranged between the collars.

That embodiment still uses the collars of the internal plates but the collars introduce themselves into a roller, and the articulation pin of the links extends through the whole. The rollers cooperate with the pinions and, as before, transmit the forces of the pinions directly onto the plates of the internal link.

According to another advantageous feature, the plates of the links have straight or recessed sides.

The straight sides have the advantage of simplicity.

However, when the chains are supported on curved guides, such as distribution chains, it is desirable for the plates of the links to have recessed sides in order to provide two points of contact with the curved guide surface, preferably a single point of contact in the case of a link having straight sides. That enables the contact pressure between the chain and the guide member to be reduced and the links to be maintained in a stable position on all curved guide devices, which reduces the extraneous vibrations of the chain in the course of operation and reduces noise and wear on the chain.

The present invention will be described hereinafter in a more detailed manner by means of an embodiment shown diagrammatically on an enlarged scale in the appended drawings, in which: - Figure 1 is a partially sectional top view of a portion of the chain according to the invention, - Figure 2 is a vertical section on II-II of the chain of Figure 1, - Figure 3 is a sectional view analogous to that of Figure 2 showing an articulation according to the prior art, - Figure 4 is a view analogous to that of Figure 1 of another embodiment of a chain according to the invention, - Figure 5 is a view analogous to that of Figure 1 of a second variant, - Figure 6 is a side view of a chain having links with straight sides, - Figure 7 is a side view of a chain having recessed links, - Figure 8 shows the contact between a link of the chain having straight sides according to Figure 6 and a curved surface, and - Figure 9 shows the contacts between a link, having recessed sides, of a chain according to Figure 7 and a curved guide surface.

According to Figures 1 and 2, the invention relates to a transmission chain, such as a chain of an internal combustion engine, which ensures transmission of movement in respect of engine timing or the driving of the oil pump or the balancing of the camshaft.

Such a chain is composed of links 1 having external plates and links 2 having internal plates, the links being connected by pins 3.

The same references will be used to designate the same elements of the links of a chain.

The internal plates 21, 22 of the internal links 2 are provided with collars 211, 212; 221, 222 directed towards the inside of the links. The collars form bearings for the pins 3 connecting the internal links 2 and the external links 1.

In this first embodiment, the pin 3 is provided with a shoulder 31 which occupies the gap left between the collars 211, 221 or 212, 222.

Figure 2 shows, in section, the structure in the region of the articulation by the pin 3, demonstrating the reduction in the number of components forming the articulation, and also the improvement in the lubrication of the articulation bearings, by oil passages constituted by the play (J) between the collars 221, 222 and the shoulder 31.

Thus, Figure 3 shows, by way of comparison, a section analogous to that of Figure 2 of an internal link according to the prior art, with the two internal plates 5, 6 connected by a sleeve 7 receiving an articulation pin 3', like the pin 3, carrying the external links 11', 12'.

Figure 4 shows a first variant which is distinguished from the previous embodiment in that the pin 3A is not provided with a shoulder; the collars 212, 222 are separated by a roller 31A which has a function similar to that of the shoulder 31 of Figure 1.

The other elements of the chain are identical to those of the first embodiment.

In the second variant, represented in Figure 5, the pin 3B does not have a shoulder or a roller. On the other hand, the collars 212, 222 carry a roller 31B which is not arranged directly on the pin 3B; the collars 212, 222 engage in the roller 31B.

Figures 6 and 7 are side views of two embodiments of link plates. According to Figure 6, the plates 11 (12) of the external links 1 and those 21 (22) of the internal links 2 have straight sides 213, 223.

In contrast, in the other embodiment, represented in Figure 7, the sides 214, 224 of the internal plates 21 (22) and the external plates 11 (12) of the internal links 2 and the external links 1 are recessed and not straight. The concave shape has the references 214, 224, respectively.

Figures 8 and 9 show the support of a link having straight sides 1, 2 on a curved surface 300 which theoretically has only one point of contact 301 and the support of an internal and external link 1A, 2A having inwardly curved sides 213, 223 on a curved surface 300 which has two points of contact 302, 303.

Claims

1. Transmission chain of an internal combustion engine for engine timing, driving the oil pump and balancing the camshafts, which chain is composed of links having internal and external plates connected by pins, characterised in that the plates (21, 22) of the internal links (2) are provided with collars (211, 212, 221, 222) facing the inside and forming the bearings of the articulation pins (3) between the internal links (2) and the external links (1).

2. Transmission chain according to claim 1, characterised in that the collars (211, 212, 221, 222) are produced by stamping from the plates (21, 22) of the internal links (2).

3. Transmission chain according to claim 1, characterised in that the links have straight or recessed sides.

3. Transmission chain according to claim 1, characterised in that the pin (3) is provided with a shoulder (31) occupying the gap between the edges of the collars (211, 212, 221, 222) of the plates (21, 22) of the internal links (2).

4. Transmission chain according to claim 1, characterised in that the pin (3A) is provided with a roller (31A) through which the pin (3A) extends and which is arranged between the collars (211, 212, 221, 222) of the plates (21, 22) of the internal links.

5. Transmission chain according to claim 1, characterised by a roller (31B) which is coaxial with the pin (3B) and the ends of which accommodate the collars (211, 212, 221, 222) of the plates (21, 22) of the internal links (2).

6. Transmission chain according to claim 1, characterised in that the links have straight or recessed sides. Amendments to the claims have been filed as follows CLAIMS 1. Transmission chain of an internal combustion engine for engine timing, driving the oil pump and balancing the camshafts, which chain is composed of links having internal and external plates connected by pins, the plates (21, 22) of the internal links (2) being provided with collars (211,212,221,222) facing the inside and forming the bearings of the articulation pins (3) between the internal links (2) and the external links (1) characterised in that the pin (3) is provided with a shoulder (31) occupying the gap between the edges of the collars (211, 212,221,222) of the plates (21, 22) of the internal links (2).