GB2529303A

GB2529303A - Multiple casing fixing

Info

Publication number: GB2529303A
Application number: GB1511276.6A
Authority: GB
Inventors: Dan Barclay; John Spooner
Original assignee: Jaguar Land Rover Ltd
Current assignee: Jaguar Land Rover Ltd
Priority date: 2014-06-26
Filing date: 2015-06-26
Publication date: 2016-02-17
Anticipated expiration: 2035-06-26
Also published as: GB201511276D0; GB201411375D0; GB2529303B

Abstract

A method is provided for fixing two casings 115, 125 where a first opening in a first casing 115 is misaligned with a corresponding second opening 120 in a second casing 125. A third opening 110 encompassing the first opening is made in first casing 115 and a blanking plug 145 is fitted in third opening 110. A suitable blanking plug 145 is also disclosed, comprising an outer circumferential surface having a thread or other means to fixedly retain plug 145 in third opening 110, blanking off this opening, and a threaded blind bore 142 extending into an end face of the plug. When blanking plug 145 is fitted in third opening 110, the bore is axially aligned with and opens onto the second opening. A threaded fixing means is fitted through the second opening to engage in the bore, fixing the first and second casings. The blanking plug may also have recesses 143 engageable by a locking pin spanner. Blanking plug 145 may provide access to an oilway, electrical connection or core plug.

Description

Multiple casing fixing

TECHNICAL FIELD

The present invention relates to multiple casing fixing, particularly but not exclusively a method of connecting multiple mechanical casings together for use with bolting or screw fixings, whilst maintaining positional abutment features internal to the casing. Aspects of the invention relate to a method, to a plug and to a casing.

BACKGROUND

Given the constraints which are put upon vehicle designers, it is becoming more important to miniaturise assembles to make things smaller, lighter and cheaper. Assembly methods make it important to have fixings and mounting points in readily accessible and practical places and further these fixing points need to avoid areas of the casing where internal components may impinge upon the fixing or may require precise positioning of internal componentry. This applies to automotive, aeronautical, maritime and railway machinery and could relate to any mechanical interface.

As an example it is common in automotive design to have multiple casings connected to one another, end to end, for example in the situation of a typical 4 wheel drive vehicle a combustion engine case could be bolted to a transmission case which in turn may also be bolted to a transfer case. A combustion engine may be fitted either in line' or transversely' in the vehicle. Typically a multi speed ratio manual or automatic transmission will be connected directly to the rear face of the engine block, sometimes via a flange, such that drive can be transferred from the combustion engine to the transmission. 4x4 off road type vehicles may be provided with an additional transmission called a transfer box, transfer case or power take off unit (PTU) which usually houses a centre differential and can include an optional selectable off road' gear ratio range which provides a greater torque output and speed control at the wheels. The transfer case takes its input from the output of the conventional multi speed transmission. The transfer case output has 2 outputs, and via conventional propshafts can provide torque to the front and rear axles.

These cases (engine, transmission and transfer) can be assembled together sharing a common axis, or can be offset from each other, enabled by various gear or belt transfer arrangements. When bolted together these casing sub-assemblies make one large powertrain assembly which in turn can be mounted into a vehicle bodyshell or chassis frame, usually secured using compliant mounts and or subframe arrangements.

When fixing multiple casings together end on end using current techniques it is common for the fixing points to be positioned between the cases in places where it is most convenient and thus avoiding sensitive casing areas or places used for external casing access used for assembly purposes. The fixing method and bolt pattern needs to provide torque transfer between cases, bending force integrity, high bending stiffness, sealing and assembly access to fixings.

One regular design challenge involves making sure that the fixing methods from one case to the next case are conducive to a practical and efficient assembly technique, which can be difficult due to internal component layouts within the casings, as the internal component layouts can conflict with casing fixing positions. This invention is aimed at enabling an improved fixing positioning capability even when internal casing components would normally cause a conflict for positioning the fixings.

To be clear the term fixing in one example may mean a bolt with a male thread which passes through a clearance hole in a first casing which then threads into a female thread located in a threaded hole in a second casing. In a another arrangement a stud and nut combination could be used instead of a bolt, which could allow better tooling access during manufacture.

As an example the combustion engine case, transmission case and transfer case can all share shafts which run in common or parallel axes to one another. These shafts in some arrangements can run perpendicular to one another especially if a change of drive direction is required when perhaps a Bevel/Hypoid gearbox is used within the transmission case.

These various shaft arrangements typically dominate the packaging of smaller components around the shafts and can put smaller components and features like oil ways, pivot shafts, internal fixtures and sensors close to or implanted inside the case walls. The casing walls are usually made of aluminium or iron cast material and the walls are usually thinned down to minimum thickness in most places apart from around high stress areas or fixing point locations.

When designing fixing locations shared between cases, it is always a priority to be able to line up the fixing holes from one casing to the respective receiving thread in the mating case.

Sometimes there can be constraints or conflicts when positioning the bolt hole or screw fixings in casing assemblies and it is the aim of this invention to offer an improved fixing method where constraints usually make it impossible for conventional screw fix methods to be practical. Constraints or conflicts within the case, such as internal component positioning, need for precision abutment features, availability of casing material depth or strength and even desired hand access positioning for assembly may need to be catered for when determining the positions of bolt fixings and this invention may alleviate these problems.

It is common for automotive manufacturers to comnionise on engine, transmission and transfer case design where possible to minimise the number of part derivatives within the business and thereby reduce cost due to reduced development and testing.

When designing a new vehicle it is always preferable to utilise parts already available off the shelf' which have been developed and proven. The problem with utilising parts off the shelf' in terms of engines, transmissions and transfer cases is that it leads to the probability that some of the mounting holes used in previous installations may not be usable because the engine has not, for example, previously been connected to a particular transmission. The cost of changing the part to suit could be prohibitively expensive or perhaps the manufacturing tool used to make the parts is not able to be changed. This leads to a requirement to use the currently available cases with a need for a method enabling the repositioning of fixing holes within the casing. This invention seeks to provide a method to do this.

SUMMARY OF THE INVENTION

According to one aspect of the invention there is provided a method of fixing two casings together where one or more first opening in a first casing and is misaligned with a corresponding one or more second opening in a second casing, the method comprising: making a third opening in the first casing, said third opening encompassing the one or more first opening; and fitting a blanking plug within the third opening, said blanking plug comprising: an outer circumferential surface having retaining means thereon for fixedly retaining the blanking plug in the third opening so as to blank off said third opening, and at least one threaded blind bore extending into an end face thereof, wherein when the blanking plug is fitted in said third opening the one or more threaded blind bore is axially aligned with and opens onto the one or more second opening; and inserting a threaded fixing means through at least one of said one or more second opening to engage in the one more threaded blind bore so as to fix the first casing and second casing together.

The third opening may be axially aligned with, or may be axially offset from, at least one of said one or more second opening.

The threaded fixing means may be a threaded member, in particular the threaded fixing means may be a bolt or a screw.

According to another aspect of the invention there is provided a blanking plug for use in the preceding aspect of the invention, the blankng plug comprising: an outer circumferential surface having retaining means thereon for, in use, fixedly retaining the blanking plug in an opening in a first casing so as to blank off said first opening, and a threaded blind bore extending into an end face thereof.

The blanking plug may provide access to, or provides a feature to locate, hold or provide abutment for components internal to the first casing when in use.

In one embodiment the retaining means comprises a male thread formed on the outer circumferential surface of the plug. Alternatively the plug may comprise means for engaging with a fixing means comprising at least one of circlip, spring clip and/or dowel fastening means.

The blanking plug as may provide one or more of: closure to an oilway in the first casing, access to an electrical connection or sensor within the first casing, and access to fit or remove a core plug to the first casing.

The blanking plug has a central axis and the threaded blind bore may be is co-axial with the central axis of the blanking plug and/or concentric relative to the outer diameter of the threaded blind bore of the blanking plug.

The blanking plug may comprise one or more recesses or features arranged on the end face thereof containing the threaded blind bore for, in use, receiving a tool for applying torque to the blanking plug.

The blanking plug may comprise two or more said threaded blind bores each spaced in equidistance relationship to the central axis of the blanking plug, said two or more threaded blind bores may be formed are in parallel to, or at an angle to, a central axis of the blanking plug.

The blanking plug may comprise a single threaded bore is formed at an angle to a central axis of the blanking plug..

According to another aspect of the invention there is provided an assembly comprising a first casing and a second casing, said assembly manufactured according to the method of the invention described hereinabove.

Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and/or in The following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner.

BRIEF DESCRIPTION OF THE DRAWINGS

One or more embodiments of the invention wll now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a cross section of a known assembly where 2 cases are unable to be flanged and bolted together because of an internal feature in one case preventing a standard bolt fixing from being fitted; Figure 2 is a cross section of an embodiment of the invention showing fixing of two casings in accordance with the invention; Figures 3A-C show a cross section of an embodiment of the invention illustrating the formation of the blanking plug; Figures 4A-C show a cross section of another embodiment illustrating the formation of the blank plug; Figure 5A-B show a cross section of embodiments illustrating arrangement of fastening recess or features of the blanking plug; and Figure 6 shows an embodiment illustrating fastening means arrangement relating to the blanking plug of Figures 2 to 5.

DETAILED DESCRIPTION

A method of connecting multiple mechanical casings together using bolting or screw fixings is described herein, in accordance with an embodiment of the present invention with reference to the accompanying Figures.

It is understood that by the term "blanking plug", it is meant a piece of material that is capable of being insert into an opening of a housing and act as a sealant for the opening and provide an engageable means between the housing and any other components so that the other components can be attached to the housing.

Figure 1 shows an arrangement of a known approach highlighting a problem encountered when mounting multiple casing flanges TogeTher, while maintaining internal access features necessary to assemble sub-assemblies from the outside of the casing. Figure 1 shows that in this instance the fixing bolt (45) would foul the blanking plug (20) if the bolt (45) was slid through the hole (Hi) in casing (40) as there is no possibility of a thread being cut in the casing (30) along axis (Xia).

In this known arrangement, pivot pin (10) is housed within a transmission assembly (15) and is the pivot for a transmission park pawl (80). During assembly of the transmission (15) the pivot pin (10) is inserted through the access hole (60) (with blanking plug (20) removed) of the transmission case (30) and locates the park pawl (80) from the direction of arrow (A) down the axis (Xl).

During assembly the pivot pin (10) slides through the external locking mechansm entrance which in this case is an internal threaded orifice within the access hole (60) which is present in transmission casing (30) before it slides into the park pawl (80). Once the pivot pin (10) is slid into position the known blanking plug (20) is screwed into position from the direction indicated by arrow (A) along axis (Xl) and provides a locating abutment at the surface (Si) for the pivot pin (10). The blanking plug (20) ensures that the pivot pin (10) is held in position in the transmission and at the same time the blanking plug seals the transmission to prevent oil leakage from the transmission and water and dust ingress. It will be noted that the blanking plug (20) is fitted in the transmission casing (30) with an AIIenTM type recess (50) for assembly and final tightening. This allows the blanking plug (20) to be screwed into position such that the outer end of the blanking plug (20) can be screwed flush to the surface (S2) and does not protrude above surface (S2) once the blanking plug (20) is in its fitted position. Note that the blanking plug (20) fully fitted position could be provided by being tightened up against the end of the pivot pin (10) or as an alternative the blanking plug (20) could tighten up against a known recess shoulder arrangement on the case (30) itself. This would have the advantage of not having to apply axial pressure to the pivot pn (10) in the direction of arrow (A), allowing the pivot pin (iO) to rotate freely if and as required.

After the blanking plug (20) is fully fitted into position the transfer case casing (40) can then be abutted against the mating flange of the transmission case (30) and be fitted flush to surface (S2) against the outer flange of the transmission casing (30) without hindrance. In this arrangement where the transfer case (40) and transmission case (30) need to be connected to each other it is usual to use traditional bolting methods but in some circumstances the position of case features or internal components can form an obstruction to positioning of the known bolt and thread fixings. To be clear in the known arrangement of figure 1 it would be impossible to fit a threaded bolt through either of the holes (Hi, H2) or therebetween axes (Xia, Xib) in transfer case (40) and insert it into a threaded hole in case (30) as the blanking plug (20) is in the way, and making it impossible for a female thread to be placed into case (30). In the arrangement shown, holes Hi and H2 are holes which are pre-existing in the transfer case (40). As noted earlier herein, such holes may readily exist where a component such as the transfer case (40) here has previously been fitted to a different transmission casing other than the transmission casing (30), where that other transmission casing was manufactured with threaded holes that aligned with the present holes Hi and H2.

Figure 1 shows that if the bolt (45) were to be slid through either of the holes (Hi, H2) along axes (Xia, Xib) then they would run up against the end of the blanking plug (20) at the surface (S2). The invention seeks to solve this problem and provides a method that allows successful assembly and bolted connection of the transmission case (30) to transfer case (40).

Figure 1 shows a known prior art as discussed in the background section.

Figure 2 shows an embodiment of the invention wherein the blanking plug (145,245) is in engagement with the first casing (115) allowing an improved positioning of the bolt fixings. A transmission (108) is used as an example but the invention is not limited to the application to a transmission only. The transmission (108) has a requirement of a pivot pin (i05) being assembled into the a first casing (115), which is the casing for the transmission (i08) in this example, by removal of a blanking plug (145, 245) from the first casing (115) as a means of external access. The pivot pin (105) is being assembled into the transmission (108) in the direction of arrow (B) down axis (Xi). The blanking plug (145, 245) could be screwed into position from the direction indicated by arrow (B) along axis (X2) and provides a locating abutment at the surface (S3) for the pivot pin (105).

Figure 2 shows an example of a pivot pin (100) being assembled into the transmission (108) by removal of the blanking plug (145) as a means of external access. There are other internal casing features which could require similar blanking plug access points, such as transmission shaft entry points, casing oilways, circlip access points, core plug entry points and wiring harnesses. This is not an exhaustive list and they are only provided as examples which are non-limiting.

In another embodiment, instead of having a pivot pin (100), access may be required to provide closure to an oil gallery which may be providing hydraulic fluid to a clutch or cooling system in the first casing (115).

In another embodiment, instead of having a pivot pin (100), access may be required to fit and provide an abutment feature ensuring security of a core plug required in the first casing (115).

In another embodiment, instead of having a pivot pin (100), access may be required to fit an internal circlip within the first casing (115). The circip may be required to secure a shaft as an example and may be internal or external.

In another embodiment, instead of having a pivot pin (100), access may be required to fit or remove a wiring harness or sensor internal to the first casing (115). The wiring harness may have to be pushed around a bend or maybe there is a need for an electrical connection point within the first casing (115) at a critical point during assembly.

In this embodiment, the modified blanking plug (145, 245) is cylindrical in shape, having an outer form, such as an external thread, to interface with the casing (115). The blanking plug (145, 245) comprises a threaded blind bore (142) wherein a receiving thread is formed along the central axis (X2) of the blanking plug (145, 245).The threaded bore (142) is suitable for receiving a fixing used to secure a second casing (125) to the first casing (115).

The threaded bore (142) is a blind bore opening onto the side of the first caseing (115) that abut the second casing (125). The blanking pug (145) is secured into position by means of its external threaded surface engaging with a female thread (110) formed into the first casing (115) using one or more recesses or features (143), which can be a standard multiple recesses, and a locking pin spanner (not shown). When fitted fully into position the end face (140) of the blanking plug (145) will be flush or below the surface to surface (S4) of the first casing (115). The second casing (125) can now be abutted to the first casing (115) at the interface surface (S4) and the fixing bolt (130) can be slid through hole (120) in the second casing (125) along axis (X2) in the direction of arrow B. The fixing bolt (130) is tightened up in the threaded blind bore (142) and pulls the second casing (125) against the first casing (115) at surface (S4).

The outer form of the blanking plug is not limited to being a thread as in the embodiment.

The outer form may be formed to engage with fastening means such as a circlip, spring clip, dowel, cam locking. In another embodiment, the blanking plug (145) can be engaged to the first casing (115) using adhesive, or may, for example, be a push fit.

The invention provides an advantage that by inserting the blanking plug (145) in the first casing (115) the threaded blind bore (142, 242) is created along the axis (X2), which is the ideal position to engage the second casing (125) as it aligns with the second opening (120, 2) of the second casing(125). It is clear that the known blanking plug (20) as shown in figure 1, is not capable of providing an opening at such position because it requires to use Allen head (50) within the blanking plug (20) leaving no flexibility to the formation of the blanking plug.

Figure 3A shows a first casing (115) and a second casing (125) placed adjacent to each other in alignment where each casing has an opening/hole respectively. These openings (1, 2) are not aligned.

Figure 3B shows an assembly of the first casing (115) and the second casing (125) where the blanking plug (145) is inserted into the first casing (115). The blanking plug (145), as shown in Figure 3C, has a receiving bore (142) which is formed in the centre of the blanking plug (145). The threaded blind bore (142) is formed so that the central axis X of the blanking plug (145) and the threaded blind bore (142) has a central axis are co-axial. The blanking plug (145) and the threaded blind bore (142) are concentric.

When the blanking plug (145) is engaged with the first casing (115) as shown n Figure 3B, the central axis X of the blanking plug (145) is aligned with the central axis of the opening (2) of the second casing (125) so that the threaded blind bore (142) is concentric to the opening of the second casing (125). This allows access to fastening means and the first casing (115) and the second casing (125) to be attached together.

The blanking plug (145) is made to match where a third opening (not shown) is created in the first casing (115) axially aligned to the second opening (2) of the second casing (125) and radially encompassing the first opening (1) of the first casing (115).

Figure 4A shows the predicament shown in Figure 2 and 3A where the openings (1, 2) of the first casing (115) and the second casing (125) are misaligned.

Figure 4B shows the blanking plug (245) engaged to the first casing (115). Figure 4C show the blanking plug (245) comprising the threaded blind bore (242) which is offset from the central axis (Y) of the blanking plug (245). The central axis (7) of the threaded blind bore (242) is offset from the central axis (Y) of the blanking plug (245).

The blanking plug (245) is made by enlarging the opening (1) of the first casing (115) radially to encompass the opening (2) of the second casing (125).

Figure 5A and SB show embodiments of the arrangement for fastening the blanking plug (145, 245) to the first casing (115). The blanking plug (145, 245) has two threaded blind bores (300, 400) formed in a same surface, spaced apart from each other, in equidistance (d) from the central axis of the blanking plug (145, 245). In Figure SA the two or more recesses or features are formed in parallel with respect to each other and parallel to the central axis (Y) of the blanking plug (145, 245). In the embodiment shown in SB, the two threaded blind bores (400) are formed in the same surface at an angle 8 from the central axis (Y) of the blanking plug (145, 245). The two or more recesses or features (400) may be equidistance and at an angle from the central axis (1) of the blanking plug (145, 245).

Figure 6 shows the blanking plug (145, 245) engaged with the first casing (115) using a circlip (500) where the arrangement provides an 0-ring (501) to seal the opening of the first casing (115) It will be appreciated that various changes and modifications can be made to the present invention without departing from the scope of the present application.

Claims

CLAIMS: 1. A method of fixing two casings together where one or more first opening in a first casing and is misaligned with a corresponding one or more second opening in a second casing the method comprising: making a third opening in the first casing, said third opening encompassing the one or more first opening; and fitting a blanking plug within the third opening, said blanking plug comprising: an outer circumferential surface having retaining means thereon for fixedly retaining the blanking plug in the third opening so as to blank off said third opening, and at least one threaded blind bore extending into an end face thereof, wherein when the blanking plug is fitted in said third opening the one or more threaded blind bore is axially aligned with and opens onto the one or more second opening; and inserting a threaded fixing means through at least one of said one or more second opening to engage in the one more threaded blind bore so as to fix the first casing and second casing together.
2. The method according to claim 1 wherein said third opening is axially aligned with, or axially offset from, at least one of said one or more second opening.
3. A method as claimed in claim 1 or claim 2 wherein the threaded fixing means is a threaded member.
4. A method as claimed in 1 or claim 2 wherein the threaded fixing means is a bolt or a screw.
5. A blanking plug for use in the method of claim 1, the blanking plug comprising: an outer circumferential surface having retaining means thereon for, in use, fixedly retaining the blanking plug in an opening in a first casing so as to blank off said first opening, and a threaded blind bore extending into an end face thereof.
6. A blanking plug as claimed in claim 5 wherein the blanking plug provides access to, or provides a feature to locate, hold or provide abutment for components internal to the first casing when in use.
7. A blanking plug as claimed in claim 5 or claim 6 wherein the retaining means comprises a male thread formed on the outer circumferential surface of the plug.
8. A blanking plug as claimed in claim 6 or claim 7 wherein the plug comprises means for engaging with a fixing means comprising at least one of circlip, spring clip and/or dowel fastening means.
9. A blanking plug as claimed in claims 5 to 8 wherein the plug provides closure to an oilway in the first casing.
10. A blanking plug as claimed in caims 5 to 9 wherein the plug provides access to an electrical connection or sensor within the first casing.
11. A blanking plug as claimed in claims 5 to 10 wherein the blanking plug provides access to fit or remove a core plug to the first casing.
12. A blanking plug as claimed in claims 5 to 11 wherein the blanking plug has a central axis and the threaded blind bore is co-axial with the central axis of the blanking plug and/or concentric relative to the outer diameter of the threaded blind bore of the blanking plug.
13. A blanking plug as claimed in claims 5 to 12 wherein the blanking plug comprises one or more recesses or features arranged on the end face thereof containing the threaded blind bore for, in use, receiving a tool for applying torque to the blanking plug.
14. A blanking plug as claimed in claims 5 to 13 comprising two or more said threaded blind bores each spaced in equidistance relationship to the central axis of the blanking plug, said two or more threaded blind bores formed are in parallel to a central axis of the blanking plug..
15. A blanking plug as claim in claims 5 to 13 comprising two or more said threaded blind bores each spaced in equidistance relationship to the central axis of the blanking plug, said two or more threaded blind bores formed at an angle to a central axis of the blanking plug.
16. A blanking plug as claimed in claims 5 wherein the blanking plug has a central axis and the one or more threaded bore is formed at an angle to a central axis of the blanking plug..
17. An assembly comprising a first casing and a second casing, said assembly manufactured according to the method of claim 1.
18. A method substantially as described herein with relation to Figures 2 toG.
19. A blanking plug substantially as described herein with relation to Figures 2 to 6.
20. A assembly comprising a first casing and a second casing substantially as described herein with relation to Figures 2 to 6.