GB2077863A

GB2077863A - Mounting Arrangement

Info

Publication number: GB2077863A
Application number: GB8111507A
Authority: GB
Original assignee: Lucas Industries Ltd
Current assignee: ZF International UK Ltd
Priority date: 1980-05-31
Filing date: 1981-04-13
Publication date: 1981-12-23
Also published as: GB2077863B

Abstract

A mounting arrangement for mounting a body 10 e.g. of a fuel injection pump upon a support structure 17 to allow limited angular movement about an axis 13. To this end the body includes a flange 10A and a cylindrical portion 18. The latter is a close fit within a cylindrical aperture 19 in the support structure to allow the body to move about the axis 13 of the aperture. The flange has at least one cylindrical aperture 21 spaced from the axis 13, the aperture 21 having an axis 22. A cylindrical member such as a bolt or pin on the support structure extends through the aperture and has a smaller diameter than the aperture and has its axis 23 offset from the axis 22. The aperture is provided with a tight fitting bush 25 having a D-shaped slot 26 the sides of which engage the bolt. The angular setting of the bush in the aperture can be pre-adjusted to determine upon assembly of the angular setting of the body 10 about the axis 13. <IMAGE>

Description

SPECIFICATION Mounting Arrangement This invention relates to a mounting arrangement for mounting a body on a support structure and of the kind comprising co-operating means on the body and support structure whereby the body and support structure can be moved angularly relative to each other about an axis, a flange formed on the body, an aperture in said flange, said aperture being spaced from said axis in a radial direction and means secured to said support structure and extending through said aperture to provide location of said body and said support structure about said axis.

Such a mounting arrangement can be utilised to locate an injection pump body on a support structure, for example an engine housing or in some instances, a fuel injection pump body which is in turn secured to the engine housing. In both cases relative movement of the bodies and the support structure will alter the fuel delivery characteristics of the injection pump. In the past it has been the practice to provide an elongated aperture to allow for relative adjustment of the body and the support structure about said axis during assembly thereof. Scuh means of adjustment is not positive and other means must be employed to ensure correct adjustment for each assembly.

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

According to the invention in a mounting arrangement of the kind specified, said means comprises a cylindrical member and said aperture is of cylindrical form having a diameter larger than the diameter of said cylindrical member, with its axis being offset from the axis of the cylindrical member, the arrangement including a cylindrical bush located in said aperture, said bush having a D shaped slot formed therein, the sides of said slot engaging said cylindrical member to locate the body and support structure about said first mentioned axis, said bush being capable of angular adjustment within said aperture prior to the assembly of the body and support structure.

An example of a mounting arrangement in accordance with the invention will now be described with reference to the accompanying drawings in which: Figure 1 shows a part sectional side elevation of a so-called "in-line" fuel injection pump; Figure 2 is a plan view of the pump shown in Figure 1; Figure 3 is a view to an enlarged scale showing the geometry of the mounting arrangement; and Figure 4 shows the form of mounting arrangement used heretofore.

Referring to the drawings and in particular to Figure 1, the injection pump comprises a body 10 mounting an outlet union 11. Located within the body 10 is a pump barrel a portion of which is seen at 12. The barrel is provided with a cylindrical bore, the axis of which is indicated by the dotted line 13, and slidable within the bore is a pump plunger which has a projecting portion 14.The projecting portion is engageable in use, by a tappet assembly which co-operates with a cam on a cam shaft, to effect inward movement of the plunger against the action of a coiled compression spring 1 5. In known manner, the barrel defines a port through which fuel can be spilled from the pumping chamber to terminate delivery of fuel through the outlet 11. For this purpose the plunger is provided with an inclined groove which uncovers the port at a predetermined position during the inward movement of the plunger. The angular setting of the plunger is adjustable so that the aforesaid predetermined position can be adjusted and in this manner the quantity of fuel delivered through the outlet can be varied.An arm 1 6 is provided which is movable about the axis 1 3 and which determines the angular position of the plunger.

The body 10 is mounted on a support structure which is indicated at 17 and a plurality of such pumps may be mounted on the support structure to form what is termed in the art, an "in-line" pump capable of supplying fuel to a multi-cylinder engine. The arms 16 of the various pumps are interconnected by means of an actuating rod which is slidably mounted in the support structure 1 7 which also carries the aforesaid cams, these being mounted on a cam shaft.

It is necessary to ensure that each pump for a given setting of the actuating rod, delivers the same amount of fuel and one method of ensuring that this is obtained, is to adjust the setting of the bodies 10 about the respective axes 13. This process is called in the art the calibration of the apparatus.

The body 10 is provided with a cylindrical portion 1 8 which is a close fit within an aperture 19 formed in the support structure, the axis of the aperture 1 9 coinciding with the axis 13.

Moreover, the body 10 defines what in effect is a flange 1 OA and in the past, it has been the practice to form apertures indicated at 20 in Figure 4, in the flange, the apertures being elongated in a circumferential direction about the aforesaid axis 13. Retaining means for example threaded studs carried by the support structure 17, or bolts engageable therewith, have been passed through the apertures 20 and by careful adjustment of the body 10 relative to the support structure prior to and during the tightening ofthe bolts, it has been possible to achieve the desired calibration.When the apparatus is in use however, some malfunction may occur which makes it necessary to remove one of the pumps and whilst this is a simple task, since it only requires that the retaining bolts should be undone together with any fuel connections, it has meant that the process of recalibration must be repeated for that one pump which is replaced. In general therefore the whole apparatus must be removed from the engine and the calibration carried out in a suitable test rig. This is an expensive and time consuming operation and it would be much simpler if a new pump could be assembled which has already been calibrated. This would enable the servicing to be carried out without removing the apparatus from the engine. In order to achieve this object the flange is provided with a pair of cylindrical apertures 21 of substantially larger diameter than has hithertofore been the practice.

The axes of the apertures 21 are indicated by the dotted lines 22 and these axes are off-set from the axes indicated at 23, of the securing means 24 shown in Figures 2 and 3. The securing means is of cylindrical form and may for example be a locating pin carried by the support structure or it may be the shank of a bolt or stud engageable therewith. Whatever the form of the retaining means, the diameter is smaller than the diameter of the apertures 21.

Located in the apertures are bushes 25. These are of cylindrical form and conveniently are a tight push fit within the apertures 21. Moreover, the bushes are provided with D shaped slots 26 the sides of which engage with the cylindrical portion of the retaining means 24.

As shown in Figure 3, by altering the angular setting of the bush 25 within the aperture 21, so the relative angular setting of the body 10 and support structure 1 7 about the axis 13 can be varied. Figure 3 shows two settings and also indicates by the arrows, the range of adjustment which may be obtained, it being appreciated that the range of adjustment of the bushes 25 from the position shewn in Figures 1 and 2, should not be more than say 600. If the bushes are turned through more than 600 the accuracy of location is impaired and indeed if the bushes are turned through 900 then whilst the sides of the slots are parallel, as opposed to being curved, the equivalent of the slot 20 is obtained.

The invention has been described as applied to an in-line pump and the calibration of the individual pumps forming the in-line pump. It is also applicable to the mounting of a rotary distributor pump upon the associated engine, and in this case it is the timing of delivery of fuel which is varied by adjusting the fuel injection pump body on the engine housing. It is also applicable to some in-line pumps which are utilised to supply fuel to a small engine of say two or four cylinders which are flange mounted on the engine. In these two cases the axis 13 is the axis of rotation of the drive shaft of the pump.

As previously stated the bushes 25 are a tight fit within the apertures and the initial angular setting of the bushes within the apertures is carried out on a suitable test rig. Once the correct angular position for the body about the axis 13 has been discovered, then the bushes are pressed into the apertures to achieve a semi-permanent fixing. The bushes shown in the drawings are provided with flanges so that the extent of movement into the apertures is limited. These flanges are not essential and the bushes can be of plain cylindrical form.

Claims

1. A mounting arrangement for mounting a body upon a support structure and comprising co,- operating means on the body and support structure whereby the body and support structures can be moved angularly relative to each other about an axis, a flange formed in the body, an aperture in said flange, said aperture being spaced form said axis in a radiai direction, means secured to said support structure and extending through said aperture to provide location of said body and said support structure about said axis, said means comprising a cylindrical member, said aperture being of cylindrical form and having a diameter larger than the diameter of said cylindrical member with its axis being offset from the axis of the cylindrical member, the arrangement including a cylindrical bush located in said aperture, said bush having a D-shaped slot formed therein, the sides of said slot engaging said cylindrical member to locate the body and support structure about said first mentioned axis, said bush being capable of angular adjustment within said aperture prior to the assembly of the body and support structure.

2. A mounting arrangement according to claim 1 or claim 2 in which said bush is tight push fit within the aperture.

3. A mounting arrangement according to claim 1 or claim 2 in which said bush is provided with a flange.

4. A mounting arrangement according to any one of the preceding claims in which said cooperating means comprises a cylindrical portion on the body and a cylindrical aperture in the support structure, said cylindrical portion being close fitting within the aperture.

5. A mounting arrangement for mounting a body on a support structure substantially as hereinbefore described with reference to the accompanying drawings.