GB2177450A

GB2177450A - Clamping device for fuel injection nozzle

Info

Publication number: GB2177450A
Application number: GB08613734A
Authority: GB
Inventors: Richard Michael Turner
Original assignee: Lucas Industries Ltd
Current assignee: ZF International UK Ltd
Priority date: 1985-06-27
Filing date: 1986-06-06
Publication date: 1987-01-21
Also published as: GB8613734D0; GB8516236D0

Abstract

A clamping device for clamping a fuel injection nozzle within a bore in an internal combustion engine is formed from a length of hollow square section material with a first aperture 19 in one wall to allow the side walls of the section of material to engage ledges defined on opposite sides of the nozzle, a second aperture 20 in the opposite wall to said one wall to allow the nozzle body to pass therethrough. The ends of the section are obliquely cut leaving webs 22 interconnecting the side walls in the region of the first aperture and holes 23 are provided in said opposite wall to receive retaining bolts to allow the clamping device to be secured to the cylinder head of the engine. <IMAGE>

Description

SPECIFICATION Clamping device This invention relates to a clamping device for use when clamping a fuel injection nozzle within a bore in an internal combustion engine.

Known clamping devicesforthis purpose comprise forgings which are of substantial thickness to withstand the loads to which they are subjected in use. This form of clamping device is therefore heavy and expensive to manufacture.

Cheaper forms of clamping device are known from British Patent Specifications 1427049 and 1549740 and PCT Specification WO 84/02161. The devices shown in the latter two specifications are formed from tube stock and that in the first specification from channel section material. A disadvantage with this form of construction is the lack of lateral rigidity which can allow the portions of the clamping device which engage the ledges or steps of the nozzle body to spread. This tendency increases as the ledges wear. A stiffer form of clamping device again constructed as a pressing from channel section material, is described in British Published Specification 2100334A. However, the device described in this specification has proved difficult to manufacture to the accuracy required.

The object of the present invention is to provide a clamping device for the purpose specified in a simple and convenient form.

According to the invention a clamping device for the purpose specified comprises an elongated body portion formed from hollow rectangular section material, a first aperture formed in one wall of the body portion, the width of said aperture being substantially equal to the internal width of said one wall and the length of the aperture being sufficient to allow the device to be assembled onto the body of the nozzle, the side walls of the body portion connecting with said one wall engaging in use, ledges on opposite sides of the nozzle body, a second aperture in the wall of the body portion opposite said one wall, said second aperture being of a width and length sufficient to allow said side walls to engage said ledges, further apertures formed in said wall beyond the ends of said second aperture respectively, the ends of the length of material being obliquely cut so as to leave transverse strengthening webs at the ends of said first aperture respectively, while allowing retaining bolts to be passed through said further apertures respectively.

An example of a clamping device in accordance with the invention will now be described with reference to the accompanying drawings in which: Figure 1 is a part sectional side elevation showing a fuel injection nozzle mounted in a bore in an internal combustion engine and retained therein by the clamping device, Figure 2 is a perspective view of the clamping device, and Figure 3 is an inverted plan view thereof.

Referring to Figure 1 of the drawings there is indicated at 10 an engine structure in which is defined a bore 11 having a reduced portion 12A extending from the inner end of the bore to the combustion space of the engine. Located in the bores is a fuel injection nozzle which includes a main body 12 located in the bore 11, and an extension 13 which is located within the reduced portion 12A of the bore and which at its end disposed in the combustion chamber, is provided with outlet orifices through which fuel can flow into the combustion chamber. The nozzle is provided with a fuel inlet 14 and a drain outlet 15, a sealing washer 16 is located between the step defined by the bores and the annular surface defined by the main body 12 of the nozzle.

The main body of the nozzle defines a pair of ledges 16A disposed on opposite sides of the body, the ledges being formed by machining flats 17 on the opposite sides of the generally cylindrical body.

Aclamping device 18 defines surfaces which engage with the aforesaid ledges 1 6A to retain the nozzle within the bore. The clamping device as shown in the three figures of the accompanying drawings, is formed from hollow rectangular section material this in the particular example being of substantially square section having an internal side length substantially equal to the spacing of the flats 17. In one wall of the body portion of the clamping device is formed a first aperture 19. The width of the aperture is equal to the spacing between the flats and the length of the aperture is slightly larger than the diameter of the body of the nozzle.A complementary or second aperture 20 is formed in the opposite wall of the body whereby the device can be engaged over the nozzle prior to the connection of the outlet 15, so that the edges of the sides of the body can engage the ledges 16A. As will be seen from Figure 1, the aforesaid sides as indicated at 21 are radiused and present convex surfaces to the ledges.

The ends of the body portion of the clamping device are cut obliquely but care is taken to ensure that the cut does not extend as far as the aperture 19.

In this manner transverse strengthening webs 22 are formed interconnecting the side walls which engage the ledges 16A. Moreover, formed in the wall in which the aperture 20 is formed are a further pair of apertures 23, these apertures being disposed adjacent the opposite ends respectively of the aperture 20. The apertures 23 serve to accommodate screw threaded retaining bolts 24 which are secured in complementarily screw threaded bores formed in the cylinder head of the engine.

When the bolts 24 are tightened the curved edges 21 of the side walls of the body portion of the clamping device are urged into contact with the ledges 16A and a compressive force is applied to the nozzle body to establish a gas-tight seal between the nozzle body and the cylinder head. The curvature of the edges 21 and the fact that the distance between the webs 22 is greater than the diameter of the body portion, allow for tilting of the clamping device as the bolts are tightened and the transverse webs 22 provide lateral support for the curved edges 21 to minimise the risk of the side walls of the device spreading undertheapplied load.

Claims

1. A clamping device for use when clamping a fuel injection nozzle within a bore in an internal combustion engine comprising an elongated body portion formed from hollow rectangular section material, a first aperture formed in one wall of the body portion, the width of said aperture being substantially equal to the internal width of said one wall and the length of the aperture being sufficient to allow the device to be assembled onto the body of the nozzle, the side walls of the body portion connecting with said one wall engaging in use, ledges on opposite sides of the nozzle body, a second aperture in the wall of the body portion opposite said one wall, said second aperture being of a width and length sufficient to allow said side walls to engage said ledges, further apertures formed in said wall beyond the ends of said second aperture respectively, the ends of the length of material being obliquely cut so as to leave transverse strengthening webs at the ends of said first aperture respectively, whiie ailowing retaining bolts to be passed through said further apertures respectively.

2. A clamping device according to Claim 1 in which the portions of side walls which in use engage said ledges are radiused to present convex surfaces to said ledges.

3. A clamping device for use when clamping a fuel injection nozzle within a bore in an internal combustion engine comprising the combination and arrangement of parts substantially as hereinbefore described with reference to the accompanying drawings.