GB2170293A

GB2170293A - A carrier body for a pulley assembly

Info

Publication number: GB2170293A
Application number: GB8601347A
Authority: GB
Inventors: Manfred Brandenstein; Hans Meining; Rutgerns Heemskerk
Original assignee: SKF GmbH
Current assignee: SKF GmbH
Priority date: 1985-01-25
Filing date: 1986-01-21
Publication date: 1986-07-30
Also published as: DE8501850U1; FR2577654B1; GB8601347D0; FR2577654A1; GB2170293B

Abstract

A carrier body 10 comprises a plate 13 having a bore 14 for pivotally mounting the body, a curved slot 15 which is centred on the bore 14 for receiving a securing element and limiting the range of pivotal movement, and an upstanding projection 21 which is for supporting a pulley body 12. To allow improvements in manufacture, weight and resistance to corrosion compared to metal carrier bodies, the carrier body 10 is made of plastics and has upstanding reinforcing ribs 17. <IMAGE>

Description

SPECIFICATION A carrier body for a pulley assembly This invention concerns a carrier body for a pulley assembly and a pulley assembly including the carrier body.

Patent Specification DE (OLS) 2343748 (Industriewerk Schaeffler) discloses a carrier body for a pulley assembly of the type comprising a plate having a bore for pivotally mounting the body, a curved slot which is centred on the bore for receiving a securing element and limiting the range of pivotal movement, and an upstanding projection which is for supporting a pulley body.

This know type of carrier body is made from sheet metal. A central portion of the plate, which includes the upstanding projection, is dished with a peripheral flange. The bore and curved slot are provided in the peripheral flange. To achieve a sufficiently stable and non-flexible construction relatively thick sheet metal has to be used. Accordingly, the tools in particular and thus the manufacture of this known type of carrier body is relatively expensive. This also means that the carrier body is quite heavy. Further, surface treatment is required to prevent corrosion since a pulley assembly including the carrier body mounted on the front end of an engine block is exposed to the influence of moisture and other corrosive materials.

The subject of the invention is a carrier body for a pulley assembly which can realise improvements in manufacture, weight and resistance to corrosion.

According to the invention the carrier body is made of plastics and has upstanding reinforcing ribs.

The carrier body can be made by an injection-moulding process and the direction of the ribs can be made to extend according to the direction of the expected load.

In certain applications, such as in a motor vehicle, the carrier body is mounted on the engine block but the pulley body must be spaced a particular distance from the engine block. Consequently, there is no disadvantage if the plate is thicker than known constructions. The weight can be kept low because of the material used-plastics-and the open box-like ribbed structure. Such a structure can have a good static load-carrying capacity, and be resistant to distortion and deflection. The number, thickness and direction of the reinforcing ribs can be chosen according to the particular application taking into account the principal load direction.

The plastics itself can be reinforced by the addition of glass or carbon fibres. Since plastics are commonly resistant to corrosion, no surface treatment is required.

Preferably, the carrier body includes one or more metal reinforcing elements especially in regions in which substantial loads are expected to be imposed, for example, the region surrounding the upstanding projection.

Also preferably, the upstanding projection comprises a tubular sheet metal member.

The or each reinforcing element and the tubular member are preferably sheet steel. They are insert moulded and with advantage have a projection of some form, such as a flange, to anchor them in the plastics.

Preferably, the carrier body includes apertures for the circulation of air. With the carrier body mounted on an engine block of a motor vehicle, the body will be cooled by ram air.

Possibly air ducts can be provided for cooling of the pulley body.

For special applications, a layer of a thermal insulator can be positioned between the carrier body and the engine block.

An embodiment of the invention will now be described by way of example and with reference to the accompanying drawings, of which: Figure 1 is a section on I-I of the carrier body shown in Fig. 2 and including a pulley body; and Figure 2 is a plan view of a carrier body according to the invention with the pulley body shown only in broken outline.

Figs. 1 and 2 show a carrier body 10, a rolling bearing 11 and a pulley body 12. The carrier body 10 is made of plastics by an injection moulding process. It comprises a plate 13 having a bore 14 for pivotally mounting the body 10 to, for example, an engine block of a motor vehicle (not shown) by means of a stud. The plate 13 also has a slot 1 5 which is curved along a circle centred on the bore 14 for receiving a securing element (not shown) which is fixed to the engine block. The slot 15 limits the range of pivotal movement of the carrier body 10 and thus the tension in the pulley belt. An upstanding wall 16 extends from the peripheral edge of the plate 13 and upstanding parallel ribs 17 reinforce the plate. The bore 14 and slot 1 5 are also reinforced by upstanding rims 18 and 19.

The peripheral wall 16 has a bore 20 which is used when engaging the securing element by an adjusting tool. An upstanding sleeve 21 projects from the plate 13 and has a stepped narrower portion 22, which is further from the plate and forms a shoulder, and a closed end 23. In the curved portion where the plate 13 and sleeve 21 merge there are apertures 24 for the circulation of cooling air induced by a ram effect and/or by a fan.

The bearing 11 is a single row deep-groove ball bearing with an inner ring 25, which is mounted on the narrower portion 22 and against the shoulder, an outer ring 26 and balls 27.

The pulley body 12 is a sheet metal body secured to the outer ring 26 of the bearing 11.

For reasons of clarity, Fig. 2 only shows the outline of the pulley body 12 with the pulley belt 28.

In use, the pulley belt 28 will cause a tilting load in the direction of the arrow 29 on the carrier body 10. The reinforcing ribs 17 extend in the same direction as the load. In the region between the bore 14 and the slot 15, the ribs 17 are as high as the peripheral wall 16; outside of this region they and the rims 19 are much shorter.

Claims

1. A carrier body for a pulley assembly, the carrier body comprising a plate having a bore for pivotally mounting the body, a curved slot which is centred on the bore for receiving a securing element and limiting the range of pivotal movement, and an upstanding projection which is for supporting a pulley body, wherein the carrier body is made of plastics and has upstanding reinforcing ribs.

2. A carrier body as claimed in Claim 1, wherein the carrier body includes one or more metal reinforcing elements.

3. A carrier body as claimed in Claim 1 or 2, wherein the upstanding projection comprises a tubular sheet metal member.

4. A carrier body as claimed in Claim 1, 2 or 3 and including apertures for the circulation of air.

5. A carrier body for a pulley assembly substantially as herein described with reference to and as shown in the accompanying drawings.

6. A pulley assembly comprising a carrier body as claimed in any preceding claim and a pulley body which is supported on and for rotation with respect to the upstanding projection.