BACKGROUND
Technical Field
[0001] The present invention relates generally to the field of high pressure fuel pumps.
More particularly, but not exclusively, the present invention concerns engine location
spigot adaptor for high pressure diesel fuel pumps.
Description of the Related Art
[0002] In a high pressure fuel pump, the fuel pump is usually located in relation to a front
of the engine block. This is achieved via the location of a spigot (extending from
a front plate thereof) into a bore relative to the front of the engine block. The
driveshaft passes through the spigot and on the other side of the bore, the driveshaft
attaches to a driving gear which rotates the driveshaft in operation. The spigot is
retained in position due to the bore adopting a snug fit therearound.
[0003] Typically, the bore and the location spigot of the pump have a fixed diameter of
relatively small dimensions, e.g. a spigot with a 50 mm or 68 mm diameter and a bore
of similar diameter allowing for clearance. However, such small diameters do not allow
assembly of the driving gear to the fuel pump before location of the spigot in the
engine block.
[0004] It is advantageous to allow pre-assembly of the driving gear to the fuel pump, since
it enables the fuel pump to be removed from the engine block without requiring access
to a rear of the engine block, which often requires the engine to be removed from
the vehicle.
[0005] One solution to the above problem is to increase the diameter of the bore (and therefore,
the spigot) to be larger than the driving gear, e.g. greater than 68 mm, in order
to allow the driving gear to pass through the bore and the spigot to still fit snugly
within the bore. However, this increase in the diameter of the spigot on the pump
introduces a further problem, since a spigot often interferes with the screws that
fix the pump front plate to the pump housing.
[0006] In order to tackle this further issue, it is known to use an adaptor between the
location spigot on the pump and the bore of the engine block. An adaptor allows the
spigot on the pump to remain small, thereby minimising problems with fixing the pump
front plate to the pump housing, whilst accommodating a larger bore in the front of
the engine block, thereby providing a diameter enabling assembly of the driving gear
to the fuel pump before location in the engine block.
[0007] Various adapters have been developed for this reason as described in
WO2014/190631 A1. One such prior art adaptor shown in Figure 1, comprises a loose collar 4 that sits
within the bore 2 of the engine block 1 around the spigot 3a of the pump housing 3.
The collar 4 comprises a shallow annular design with an outer peripheral o-ring seal
5 located within a groove 6 between the collar 4 and the engine block 1 and an inner
o-ring seal 7 between the collar 4 and the spigot 3a. The inner seal 7 is trapped
between the collar 4, the spigot 3a and a front plate 3b of the pump seated within
a triangular channel 8 cut into an inner rear corner of the collar 4. The seal 7 is
partly retained by a small circular segmental annular hollow 9 cut into the diagonal
wall of the channel 8. When the inner seal 7 is compressed, it applies an axial load
to the front plate 3b and collar 4 minimising axial movement of the collar 4 within
the bore 2. The depth of the collar 4 and the disposal of the inner seal 7 has to
be made such that the front plate 3b can seat against the engine block 1 in order
to avoid distortion of pump 3 geometry. However, this in turn causes an axial clearance
when the inner seal 7 is compressed, which can cause inner seal 7 fretting and failure.
[0008] Another issue with the adaptor used in Figure 1 relates to the location of the tell-tale
drilling 10 and cooperating tell-tale hole, the function of which are to help to detect
the failure of inner and outer driveshaft seals. In this case the drilling 10 exits
on a back of the front plate 3b of the pump housing 3. However, in most other pump
arrangements the inner seal 7 blocks a leak path for the tell-tale hole and so the
tell-tale function is compromised.
[0009] Accordingly, the aim is to provide an engine location spigot adaptor for high pressure
diesel fuel pumps able to minimise axial movement within an engine block bore, whilst
allowing the pump to be seated against the engine block, and which does not impinge
on the function of the 'tell-tale' drilling and hole.
[0010] Therefore, it is now desired to provide an improved arrangement for high pressure
diesel fuel pump to minimise the effects of axial clearances that lead to seal fretting
and failure. It is also desired to provide an improved arrangement for high pressure
diesel fuel pump to retain the tell-tale function of the pump.
SUMMARY OF THE INVENTION
[0011] In a first aspect of the present invention there is provided a high pressure diesel
fuel pump comprising a pump housing, a location spigot protruding from a front plate
of the pump, and a driveshaft protruding from the location spigot, the driveshaft
being adapted for assembly with a driving gear of an engine and said location spigot
being adapted to be located in a bore relative to a front end of an engine block,
the pump further comprising an adaptor for location around said location spigot in
said bore between the front plate and the engine block, the adaptor comprising a collar,
an outer seal for location between the collar and the engine block, and an inner seal
for location between the collar and the locaton spigot, characterised in that the
adaptor further comprises a spring means adapted to be located at a bottom end of
the collar between said collar and the front plate. With this arrangement using the
spring means, the adaptor is able to be seated firmly against the engine block to
minimise or even eliminate axial movement, which would otherwise lead to seal fretting
and failure. However, the use of the wave spring leaves the leak path open and un-impinged
in order to retain the tell-tale function of the pump. The spigot can remain small,
thereby minimising problems with fixing the pump front plate to the pump housing,
whilst allowing for a larger bore in the front of the engine block, to enable assembly
of the driving gear to the driveshaft before location in the engine block.
[0012] The spring means is configured to apply an axial load to the front plate when compressed.
With this arrangement, the spring means forces the adaptor against the engine block
minimising axial movement of the pump within the bore.
[0013] The spring means is adapted to be accommodated substantially within the bottom end
of the collar. Preferably, the collar comprises a recess to accommodate said spring
means.
[0014] Preferably, the collar comprises a shallow annular design comprising a centrally
disposed axial bore therethrough.
[0015] Preferably, the recess comprises an annular groove in said collar. Preferably, the
recess communicates with the bore of the collar. Therefore, most preferably, the recess
is disposed at a bottom inner corner of said collar open to said bore.
[0016] Preferably, the spring means comprises a wave spring. Preferably, the wave spring
comprises a round wire profile. Preferably, the wave spring comprises a single-turn,
e.g. one layer of wire.
[0017] The wave spring may be configured to provide between approximately 50N and approximately
2000N working load. Preferably, the wave spring is configured to provide between approximately
700N and approximately 1000N working load, more preferably between approximately 800N
and 900N.
[0018] The inner and outer seals may be located diametrically opposite one another on said
collar, e.g. on the same diametric plane. Preferably, the seals are disposed towards
an upper end of the collar.
[0019] Preferably, the outer seal comprises an o-ring of suitable sealing material. Preferably,
the outer seal is located within a groove in the outer circumference of the collar.
[0020] Preferably, the inner seal comprises an o-ring of suitable sealing material. Preferably,
the inner seal is located within a groove in the location spigot. Alternatively, the
inner seal may be located within a groove in the bore of the collar.
[0021] Preferably, the collar comprises a main portion of first outer diameter comprising
said upper end of the collar. Preferably, the collar comprises a secondary portion
of second larger outer diameter comprising said bottom end of the collar.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] For a better understanding of the invention, and to show how exemplary embodiments
may be carried into effect, reference will now be made to the accompanying drawings
in which:
Figure 1 is a cross-sectional view of a high pressure diesel fuel pump assembled within
a bore of an engine block and a prior art adaptor;
Figure 2 is a cross-sectional side view of a high pressure diesel fuel pump assembled
with a driving gear and seated within a bore of an engine block with an adaptor according
to an embodiment of the invention;
Figure 3 is a perspective view of the adaptor according to the invention as shown
in Figure 2;
Figure 4 is an exploded cross-sectional side view of a portion of Figure 2; and
Figure 5 is a perspective front view of the adaptor of Figure 3 installed on a high
pressure diesel fuel pump.
DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS
[0023] Figures 2 to 5 show a preferred embodiment of the present invention in which a high
pressure diesel fuel pump 20 comprises a pump housing 21, a location spigot 24 protruding
from a front plate 23 of the pump 20 and a driveshaft 22 protruding from the location
spigot 24, the driveshaft 22 being adapted for assembly with a driving gear 31 of
an engine and said location spigot 24 being adapted to be located in a bore 32 relative
to a front end of an engine block 30, the pump 20 further comprising an adaptor 40
for location around said location spigot 24 in said bore 32 between the front plate
23 and the engine block 30, the adaptor 40 comprising a collar 43, an outer seal 45
for location between the collar 43 and the engine block 30, and an inner seal 47 for
location between the collar 43 and the location spigot 24, characterised in that the
adaptor 40 further comprises a spring means 49 adapted to be located at a bottom end
41 of the collar 43 between said collar 43 and the front plate 23.
[0024] The adaptor 40 comprises a substantially annular collar 43 with a centrally-disposed
axial through-bore 46. The collar 43 comprises aluminium to minimise mass and reduce
the load demand on the spring means 49.
[0025] The collar 43 comprises a first bottom end 41 which sits close to the pump housing
21 and a second upper end 42. The collar 43 comprises a main portion 43a of a first
external diameter encompassing the upper end 42 and a shallow secondary portion 43b
of a second larger external diameter encompassing the bottom end 41. This provides
a stepped outer profile to the collar 43 between the bottom end 41 and the upper end
42.
[0026] The engine block 30 is adapted to receive the stepped outer profile of the adaptor
40 by comprising a secondary bore 32b concentric with the primary bore 32a and of
larger diameter to accommodate the outer diameter of the secondary portion 43b.
[0027] The main portion 43a of the collar 43 comprises an outer circumferential groove 44
disposed near to the upper end 42 for accommodating the outer seal 45. The outer seal
45 comprises an o-ring of suitable sealing material that is held within the groove
44 in order to provide a sealing interface between the collar 43 and bore 32 of the
engine block 30.
[0028] Within the main portion 43a of the collar 43, the bore 46 comprises a substantially
straight and un-profiled internal wall 46a.
[0029] In contrast, within the secondary portion 43b of the collar 43, the bore 46 comprises
a profiled internal wall 46b. Accordingly, the secondary portion 43b of the collar
43 comprises an inner circumferential recess 48 disposed within the bore 46 and open
to the bottom end 41 of the collar 43. The recess 48 comprises a substantially square
profile in cross-section. Where the recess 48 re-joins the internal wall 46b of the
bore 46, the recess 48 comprises a short, steep tapered section 51, configured to
provide a short conical portion and a diminishing gap 61 between the location spigot
24 and the internal wall 46b.
[0030] Furthermore, where the recess 48 re-joins the bottom end 41 of the collar 43, the
recess 48 comprises a second short, outwardly tapered section 52, configured to provide
a short shallow conical portion and a wider mouth 62 between the front plate 23 and
the bottom end 41 of the adaptor 40.
[0031] The mouth 62, recess 48 and gap 61 work together to provide a flow path through the
bore 46 between the front plate 23 and the collar 43 up to the point at where the
inner seal 47 is located.
[0032] The spring means 49 comprises a single-turn, round wire wave spring. The wave spring
49 is adapted to be located within the recess 48 of the collar 43. Due to the shape
of the recess 48 and the mouth 62 and gap 61, there is a flow path around the spring
49 in any compression state of the spring 49.
[0033] During assembly, the inner seal 47 is first located within the groove 25 provided
by the location spigot 24. The outer seal 45 is located within the groove 44 of the
collar 43 and the wave spring 49 is located within the recess 48 of the collar 43.
[0034] The adaptor 40 is then assembled on the pump 20, by passing the bottom end 41 over
the driveshaft 22 and then over the location spigot 24. The bottom end 41 of the collar
43 is brought close to, but generally does not abut the front plate 23 with the wave
spring 49 in uncompressed ('free') form, causing the bottom end 41 to stand off of
the front plate 23.
[0035] The collar 43 is machined to have a low clearance fit (10-85 microns diametrically)
around the location spigot 24 of the pump 20. This helps to reduce eccentricity errors
that could be detrimental to the drivetrain of the pump 20. The pressure provided
by the outer seal 45 and the inner seal 47 aids in keeping the adaptor 40 concentric
within the engine block bore 32 and the location spigot 24 concentric within the adaptor
40 bore 46.
[0036] The adaptor is held in position on the front plate 23 due to the friction between
the inner seal 47 and the collar 43 and the groove 25.
[0037] Once the adaptor 40 is in position on the pump 20, the driveshaft 22 can then be
assembled with the driving gear 31. The driving gear 31 can then be passed through
the bore 32 of the front end of the engine block 30, followed by the driveshaft 22.
The adaptor 40 and encompassed location spigot 24 pass into the bore 32, until the
secondary portion 43b of the collar 43 abuts an upper wall of the secondary bore 32b.
[0038] The pump 20-adaptor 40 assembly is then mounted on the engine block 30 by engaging
and tightening bolts (not shown). This pulls the front plate 23 of the pump 20 closer
to the bottom end 41 of the adaptor 40 and compresses the wave spring 49. The adaptor
40 is then captive between the engine block 30 and the front plate 24 within the engine
block bore 32 and does not need to be bolted itself to the pump 20 or the engine block
30.
[0039] Since the wave spring 49 is then in compressed form, the adaptor collar 43 is unable
to vibrate, which minimises seal 45, 47 fretting and failure.
[0040] In addition, the mouth 62 and the gap 61 as part of the recess 48 around the wave
spring 49 are in communication with one another around the wave spring 49, which maintains
the tell-tale leak path.
[0041] The adaptor 40 is space efficient and quick to install when compared with prior art
adaptors, since it does not require separate bolting to the pump 20 or the engine
block 30, and the collar 43 of the adaptor is instead retained on the location spigot
24 during pre-assembly via the inner seal 47. Furthermore, the wave spring 49 is capable
of provide higher axial loading, which reduces the risk of seal fretting and failure.
Finally, the tell-tale leak path is maintained since the wave spring 49 does not provide
a block at the bottom end 41 of the adaptor 40.
[0042] Although a few preferred embodiments have been shown and described, it will be appreciated
by those skilled in the art that various changes and modifications might be made without
departing from the scope of the invention, as defined in the appended claims.
1. A high pressure diesel fuel pump (20) comprising a pump housing (21), a location spigot
(24) protruding from a front plate (23) of the pump (20), and a driveshaft (22) protruding
from the location spigot (24), the driveshaft (22) being adapted for assembly with
a driving gear (31) of an engine and said location spigot (24) being adapted to be
located in a bore (32) relative to a front end of an engine block (30), the pump further
comprising an adaptor (40) for location around said location spigot (24) in said bore
(32) between the front plate (23) and the engine block (30), the adaptor (40) comprising
a collar (43), an outer seal (45) for location between the collar (43) and the engine
block (30), and an inner seal (47) for location between the collar (43) and the location
spigot (24)), characterised in that the adaptor (40) further comprises a spring means (49) adapted to be located at a
bottom end (41) of the collar (43) between said collar (43) and the front plate (23),
wherein the spring means (49) is configured to apply an axial load to the front plate
(23) and collar (43) when compressed, and,
wherein the spring means (49) is adapted to be accommodated substantially within the
bottom end (41) of the collar (43).
2. The pump according to claim 1, wherein the collar (43) comprises a recess (48) to
accommodate said spring means (49).
3. The pump according to any one of claims 1 to 2, wherein the collar (43) comprises
a shallow annular design comprising a centrally disposed axial bore (46) therethrough.
4. The pump according to claim 3 when dependent on claim 2, wherein the recess (48) is
disposed at a bottom inner corner of said collar (43) open to said bore (46).
5. The pump according to any one of claims 1 to 4, wherein the spring means (49) comprises
a wave spring (49).
6. The pump according to claim 5, wherein the wave spring (49) comprises a round wire
profile having a single-turn, e.g. one layer of wire.
7. The pump according to any one of claims 5 to 6, wherein the wave spring (49) is configured
to provide between approximately 700N and approximately 1000N working load.
8. The pump according to any one of claims 1 to 7, wherein the outer seal (45) is located
within a groove (44) in an outer circumference of the collar (43).
9. The pump according to any one of claims 7 to 8, wherein the collar (43) comprises
a main portion (43a) of first outer diameter comprising an upper end (42) of the collar
(43) and a secondary portion (43b) of second larger outer diameter comprising said
bottom end (41) of the collar (43).
1. Hochdruck-Dieselkraftstoffpumpe (20), die ein Pumpengehäuse (21), einen Ortszapfen
(24), der von einer Frontplatte (23) der Pumpe (20) absteht, und eine Antriebswelle
(22) aufweist, die von dem Ortszapfen (22) absteht, wobei die Antriebswelle (22) ausgebildet
ist zum Zusammenfügen mit einem Antrieb (31) eines Motors und der Ortszapfen (24)
ausgebildet ist zur Anordnung in einer Bohrung (32) relativ zu einem vorderen Ende
eines Motorblocks (30), wobei die Pumpe weiter einen Adapter (40) zur Anordnung um
den Ortszapfen (24) in der Bohrung (32) zwischen der Frontplatte (23) und dem Motorblock
(30) aufweist, wobei der Adapter (40) einen Kragen (43), eine äußere Dichtung (45)
zur Anordnung zwischen dem Kragen (43) und dem Motorblock (30) und eine innere Dichtung
(47) zur Anordnung zwischen dem Kragen (43) und dem Ortszapfen (24) aufweist, dadurch gekennzeichnet, dass der Adapter (40) weiter ein Federmittel (49) aufweist, das ausgebildet ist zur Anordnung
an einem unteren Ende (41) des Kragens (43) zwischen dem Kragen (43) und der Frontplatte
(23),
wobei das Federmittel (49) konfiguriert ist zum Anwenden einer axialen Last auf die
Frontplatte (23) und den Kragen (43), wenn komprimiert, und
wobei das Federmittel (49) ausgebildet ist zur Aufnahme im Wesentlichen innerhalb
des unteren Endes (41) des Kragens (43).
2. Die Pumpe gemäß Anspruch 1, wobei der Kragen (43) eine Ausnehmung (48) zur Aufnahme
des Federmittels (49) aufweist.
3. Die Pumpe gemäß einem der Ansprüche 1 bis 2, wobei der Kragen (43) eine flache ringförmige
Gestalt aufweist, die eine zentral angeordnete axiale Bohrung (46) hindurch aufweist.
4. Die Pumpe gemäß Anspruch 3, wenn abhängig von Anspruch 2, wobei die Ausnehmung (48)
an einer unteren inneren Ecke des Kragens (43) offen zu der Bohrung (46) angeordnet
ist.
5. Die Pumpe gemäß einem der Ansprüche 1 bis 4, wobei das Federmittel (49) eine Wellenfeder
(49) aufweist.
6. Die Pumpe gemäß Anspruch 5, wobei die Wellenfeder (49) ein rundes Drahtprofil mit
einer einzelnen Windung, z.B. eine Schicht aus Draht, aufweist.
7. Die Pumpe gemäß einem der Ansprüche 5 bis 6, wobei die Wellenfeder (49) konfiguriert
ist zum Vorsehen einer Arbeitslast zwischen ungefähr 700 N und ungefähr 1000 N.
8. Die Pumpe gemäß einem der Ansprüche 1 bis 7, wobei sich die äußere Dichtung (45) innerhalb
einer Nut (44) in einem Außenumfang des Kragens (43) befindet.
9. Die Pumpe gemäß einem der Ansprüche 7 bis 8, wobei der Kragen (43) einen Hauptabschnitt
(43a) mit einem ersten Außendurchmesser, der ein oberes Ende (42) des Kragens (43)
aufweist, und einen Sekundärabschnitt (43b) mit einem zweiten größeren Außendurchmesser
aufweist, der das untere Ende (41) des Kragens (43) aufweist.
1. Pompe haute pression pour carburant diesel (20) comprenant un carter de pompe (21),
un tenon de localisation (24) qui se projette depuis une plaque avant (23) de la pompe
(20), et un arbre d'entraînement (22) qui se projette depuis le tenon de localisation
(24), l'arbre d'entraînement (22) étant adapté pour être assemblé avec un engrenage
menant (31) d'un moteur et ledit tenon de localisation (24) étant adapté à être placé
dans un perçage (32) par rapport à une extrémité avant d'un bloc moteur (30), la pompe
comprenant en outre un adaptateur (40) destiné à être placé autour dudit tenon de
localisation (24) dans ledit perçage (32) entre la plaque avant (23) et le bloc moteur
(30), l'adaptateur (40) comprenant un collier (43), un joint extérieur (45) destiné
à être placé entre le collier (43) et le bloc moteur (30), et un joint intérieur (47)
destiné à être placé entre le collier (43) et le tenon de localisation (24),
caractérisé en ce que l'adaptateur (40) comprend en outre un moyen à ressort (49) adapté à être placé à
une extrémité inférieure (41) du collier (43) entre ledit collier (43) et la plaque
avant (23),
dans laquelle le moyen à ressort (49) est configuré pour appliquer une charge axiale
sur la plaque avant (23) et sur le collier (43) quand il est comprimé, et
dans laquelle le moyen à ressort (49) est adapté pour être logé sensiblement à l'intérieur
de l'extrémité inférieure (41) du collier (43).
2. Pompe selon la revendication 1, dans laquelle le collier (43) comprend un évidement
(48) pour loger ledit moyen à ressort (49).
3. Pompe selon l'une quelconque des revendications 1 et 2, dans laquelle le collier (43)
présente une conception annulaire peu profonde comprenant un perçage axial disposé
au centre (46) à travers celui-ci.
4. Pompe selon la revendication 3 prise en dépendance de la revendication 2, dans laquelle
l'évidement (48) est disposé au niveau d'un coin intérieur inférieur dudit collier
(43), ouvert vers ledit perçage (46).
5. Pompe selon l'une quelconque des revendications 1 à 4, dans laquelle le moyen à ressort
(49) comprend un ressort ondulé (49).
6. Pompe selon la revendication 5, dans laquelle le ressort ondulé (49) comprend un profil
en fil rond ayant une spire unique, par exemple une seule couche de fil.
7. Pompe selon l'une quelconque des revendications 5 et 6, dans laquelle le ressort ondulé
(49) est configuré pour appliquer une charge de travail entre approximativement 700
N et approximativement 1000 N.
8. Pompe selon l'une quelconque des revendications 1 à 7, dans laquelle le joint extérieur
(45) est placé dans une gorge (44) dans une circonférence extérieure du collier (43).
9. Pompe selon l'une quelconque des revendications 7 à 8, dans laquelle le collier (43)
comprend une portion principale (43a) avec un premier diamètre extérieur comprenant
une extrémité supérieure (42) du collier (43) et une portion secondaire (43b) avec
un second diamètre extérieur plus grand comprenant ladite extrémité inférieure (41)
du collier (43).