Mounting arrangement

Abstract: A mounting arrangement for mounting a component, for example a fuel injector, in a desired position comprises a sleeve (16) which surrounds part of the component and includes a screw-threaded end region (16 a ). At a point spaced from the first end, the sleeve (16) defines a groove (18) arranged to receive a resilient member (14) which cooperates, in use, with a groove (22) provided in the component to secure the component to the sleeve (16).

Description: This invention relates to an arrangement for mounting a component in a desired position. This invention is particularly suitable for use in mounting a fuel injector in position in a bore of an engine to permit fuel to be delivered by the injector to a cylinder of the engine. It will be appreciated, however, that the invention may also be used in other applications, for example mounting a spark plug, a sensor or a fuel line connector in a desired position. Figure 1 illustrates a known arrangement for mounting a fuel injector in position. As shown in Figure 1, an annular groove of part circular cross-sectional shape is provided in the exterior of the nozzle holder 10 of an injector 12. An O-ring or circlip 14 is received within, and protrudes from the groove. A gland nut in the form of a cylindrical sleeve 16 is located around the nozzle holder 10, the interior of the sleeve 16 being shaped, at a first end thereof, to engage the circlip 14. The exterior of the sleeve 16, at the first end thereof, is provided with a screw-threaded region which, in use, cooperates with corresponding threads provided on the interior of the bore to secure the injector 12 in position, the injector being clamped between the sleeve 16, through the circlip 14, and a step formed in the bore. The opposite end of the sleeve 16 is shaped to include flats dimensioned to permit an appropriate tool to be used to rotate the sleeve 16 to secure the sleeve 16 and injector 12 in position. It has been found that, in use, the end of the nozzle holder 10 remote from the nozzle of the injector tends to vibrate. Additionally, differential thermal expansion between the injector and some constructions of cylinder head has a tendency to reduce the clamping force and further increases the effects of vibration. Where the injector is relatively long, such vibrations are particularly disadvantageous. in order to reduce such effects, the level of strain energy can be increased, the circlip could be spaced from the first end of the sleeve, thus supporting a part of the injector remote from the nozzle. However, in order to allow assembly, the internal diameter of the part of the sleeve between the first end thereof and the circlip would have to be increased, thus reducing the wall thickness resulting in the sleeve being of undesirably reduced strength. The outer diameter of the sleeve cannot, in practice, be increased to maintain the wall thickness as the increased diameter would require the bores in the cylinder head to be of undesirably increased diameter. It is an object of the invention to provide an injector arrangement in which the disadvantageous effects described hereinbefore are reduced. Further, the lack of compliance in such an arrangement may result in undesirable loosening of the injector, in use, due to settling of the mating surfaces. CH 292199 discloses a fuel injector in which an outer sleeve surrounds part of the injector body, the sleeve being provided with a screw-threaded region and an annular groove. An O-spring ring is mounted in the annular groove and in a second annular groove provided in the injector body. According to the present invention there is provided a mounting arrangement for use in securing a component in a desired position comprising a sleeve arranged to surround part of the component, the sleeve being provided, at a first end thereof, with a fixing region, the sleeve including a first annular groove arranged to receive a substantially annular resilient member, the member being engageable within a second annular groove provided in the component, wherein the first annular groove is spaced from the first end of the sleeve, characterised in that the second annular groove includes a region defining a ramped surface arranged such that cooperation between the sleeve and the resilient member can push the resilient member over the ramped surface and out of the second annular groove to permit separation of the component from the sleeve. It will be appreciated that by locating the first annular groove away from the first end of the sleeve, the component is supported through the annular member at a location further from an end thereof than in the known arrangement, thus the disadvantageous vibrations are reduced, and the arrangement is of improved compliance. The first annular groove is conveniently of sufficient depth that the substantially annular resilient member can be received therein so as not to impede movement of the component relative to the sleeve. The fixing region conveniently comprises a screw threaded region of the sleeve. The component conveniently comprises a fuel injector. The invention will further be described, by way of example, with reference to the accompanying drawings, in which:- Figure 1 is a sectional view of a known injector arrangement; Figure 2 is a side view of a sleeve forming part of an injector mounting arrangement in accordance with an embodiment of the invention; Figure 3 is a sectional view of the sleeve of Figure 2; Figure 4 is an enlargement of part of Figure 3; Figure 5 is a diagrammatic view of the arrangement, in use; and Figure 6 is a diagrammatic view of a modification. Figures 2 and 3 illustrate a sleeve 16 forming part of an injector mounting arrangement in accordance with an embodiment of the invention. As illustrated in Figure 2, the sleeve 16 is of cylindrical form, a first end 16 a thereof being provided with external screw-thread formations arranged, in use, to cooperate with corresponding formations formed on the interior of a bore of an engine cylinder head within which the injector 10 is received. A second end 16 b of the sleeve 16 is of hexagonal form to permit the sleeve 16 to be rotated using an appropriate tool to secure the sleeve 16 in position. It will be appreciated that the sleeve may be provided with formations other than screw thread formations for securing the sleeve in position, if desired. As shown in Figures 3, the sleeve 16 includes an axially extending through bore which is of substantially uniform diameter, the diameter of the through bore being slightly larger than the diameter of the nozzle body 10 of the injector 12 to be secured in position as shown in Figure 5. At a position remote from the first end 16 a , the sleeve 16 is provided with an interior annular groove 18. As best shown in Figures 4 and 5, the annular groove 18 is of tapering depth, and the depth of the part of the groove 18 closest to the first end 16 a of the sleeve 16 is sufficiently large to enable a circlip 14 to be received entirely therein, the circlip 14 not impeding insertion of the injector 12 into the bore when in this position. Dashed lines 20 in Figures 4 and 5 illustrate the circlip 14 in this position. The injector 12 is modified so that rather than including an annular groove in a position adjacent the first end 16 a of the sleeve 16 as in the arrangement illustrated in Figure 1, the exterior of the nozzle body 10 is provided with an annular groove 22 at a location which, in use, aligns with the groove 18 provided in the sleeve 16. The location of the groove 22 is indicated by dashed lines in Figure 1, although it will be appreciated that no such groove is provided in this location in the arrangement illustrated in Figure 1. The depth of the groove 22 is substantially equal to half of the diameter of the material of the circlip 14 such that when the circlip 14 is received within the groove 22, approximately half of the diameter of the circlip protrudes from the exterior of the nozzle holder 10, this part of the circlip extending into the groove 18 provided in the sleeve 16 as shown in Figure 5. In use, prior to locating the injector 12 in the bore of the cylinder head, the injector 12 is inserted into the bore of the sleeve 16, the circlip 14 having already been located within the groove 18 of the sleeve. The action of inserting the injector 12 into the sleeve expands the circlip 14 resulting in the circlip 14 being located completely within the groove 18, the circlip 14 occupying the position indicated at 20 in Figures 4 and 5. In order to assist in expanding the circlip 14 in this manner, the end of the nozzle body 10 may be chamfered as denoted by dashed lines 24 in Figure 5. Once the circlip 14 occupies the position denoted by the dashed lines 20 in Figures 4 and 5, continued insertion of the injector 12 may continue without being impeded by the presence of the circlip 14. Such movement continues until the groove 22 provided in the exterior of the nozzle holder 10 registers with the groove 18 provided in the sleeve 16. Once such registration occurs, the circlip 14 locates within the groove 22 provided in the nozzle holder 10, the circlip protruding from the groove 22 provided in the nozzle holder 10 into the groove 18 provided in the sleeve 16, thus securing the sleeve 16 to the nozzle holder 10 whilst permitting a degree of relative axial movement of the sleeve 16 and injector 12. Once this position has been achieved, the injector 12 and first end 16 a of the sleeve 16 can be located within the bore of the cylinder head, and the sleeve 16 rotated so that the screw-thread formations provided at the first end 16 a engage with those of the bore to secure the injector 12 and sleeve 16 within the bore. As the sleeve 16 is rotated, the cooperation of the threaded formations results in axial movement of the sleeve 16 and injector 12 into the bore. Subsequently, the injector 12 engages a step located within the bore preventing further axial movement of the injector 12. Continued rotation of the sleeve 16 results in relative axial movement of the sleeve 16 and injector 12 causing the circlip 14 to move to the position shown in Figure 5 in which the circlip 14 is clamped against an end of the groove 18. In this position, the injector 12 is firmly clamped in position, the clamping force being transmitted through the circlip 14. The increased clamping length allows greater levels of strain energy to be stored in the holder body and sleeve in order to resist loosening as a result of vibration and/or by the effects of thermal expansion. It will be appreciated that the sleeve 16 is secured rigidly in position by virtue of its threaded engagement in the bore. The location of the circlip in the grooves at a position spaced from the first end of the sleeve results in a part of the injector relatively close to the end thereof remote from the nozzle being rigidly supported. Such rigid support of this part of the injector reduces movement of this end of the injector, for example resulting from vibrations. The circlip conveniently takes the form of a length of wire bent to take a substantially annular form, but it will be appreciated that other types of resilient annular member, for example an O-ring, may be used. The circlip is conveniently of oval form to assist in initial insertion of the circlip into the bore of the sleeve and the groove 18, and to assist final engagement in the corresponding groove 22 of the injector. The oval form of the circlip also reduces the risk of the circlip falling completely through the bore of the sleeve during assembly. Although the groove 22 provided in the nozzle holder 10 may be of semicircular cross-section as described hereinbefore, it is envisaged that the shape of the groove may be modified to include a ramped surface 22 a as illustrated in Figure 6. Should it be necessary to remove the injector from the sleeve 16, downward movement of the injector 12 in the orientation illustrated in Figure 6 results in the circlip 14 being forced to ride up the ramped surface 22 a until the circlip 14 occupies a position in which relative movement of the injector and sleeve is no longer impeded. Although the description hereinbefore is of an injector mounting arrangement, it will be appreciated that the invention is also applicable to arrangements for mounting other components, for example spark plugs, sensors or fuel line connectors, in their desired positions.

Claims: A mounting arrangement for a component, the mounting arrangement comprising a sleeve (16) being arranged to surround part of the component, the sleeve (16) being provided, at a first end thereof, with a fixing region (16 a ), the sleeve (16) including a first annular groove (18) arranged to receive a substantially annular resilient member (14), the member (14) being engageable within a second annular groove (22) provided in the component, wherein the first annular groove (18) is spaced from the first end of the sleeve (16), characterised in that the second annular groove (22) includes a region defining a ramped surface (22 a ) arranged such that cooperation between the sleeve (16) and the resilient member (14) can push the resilient member (14) over the ramped surface (22 a ) and out of the second annular groove (22) to permit separation of the component from the sleeve (16). An arrangement as claimed in Claim 1, wherein the first annular groove (18) includes a region of sufficient depth to permit the resilient member (14) to be received substantially completely therein. An arrangement as claimed in claim 1 or 2, wherein the resilient member (14) comprises a circlip defined by a length of wire bent to take substantially annular form. An arrangement as claimed in any preceding claim, wherein the resilient member (14) comprises an O-ring. An arrangement as claimed in any preceding claim, wherein the fixing region (16 a ) comprises a screw threaded region of the sleeve (16). An arrangement as claimed in any preceding claim, wherein the component is a fuel injector (12).

Inventors: GREEN ALAN CONWAY, STALKER CARL, STEVENS JOHN WILLIAM, GREEN, ALAN CONWAY, STALKER, CARL, STEVENS, JOHN WILLIAM
Applicants: FORD GLOBAL TECH INC, LUCAS INDUSTRIES LTD, FORD GLOBAL TECHNOLOGIES, INC., LUCAS INDUSTRIES LIMITED
Application year: 1998
Main classification: F02M61
IPC codes: F02M61