U.S. patent application number 09/929446 was filed with the patent office on 2002-04-25 for axially compact gear pump.
Invention is credited to Fiebing, Carsten, Rushen, Clive W., Thoms, Reinhardt.
Application Number | 20020048525 09/929446 |
Document ID | / |
Family ID | 9897522 |
Filed Date | 2002-04-25 |
United States Patent
Application |
20020048525 |
Kind Code |
A1 |
Rushen, Clive W. ; et
al. |
April 25, 2002 |
Axially compact gear pump
Abstract
The invention provides an axially compact gear pump comprising a
housing (13) and end plate (14). Dowels (18) extend from the
housing through the end plate to locate the end plate (14) relative
to the housing (13), and project from the end plate (14) for
locating the assembled gear pump (10) on its drive means in use.
Assembly bolts (20) extend through the housing (13) and into the
end plate (14) to hold the gear pump together for transportation
prior to use, but mounting bolts (22) for mounting the gear pump on
the drive means or on a test plate in use pass completely through
both the housing (13) and end plate (14), providing enhanced
rigidity to the assembly.
Inventors: |
Rushen, Clive W.;
(Wiltshire, GB) ; Fiebing, Carsten; (Jevenstedt,
DE) ; Thoms, Reinhardt; (Neumunster, DE) |
Correspondence
Address: |
MCKEE, VOORHEES & SEASE, P.L.C.
801 GRAND AVENUE
SUITE 3200
DES MOINES
IA
50309-2721
US
|
Family ID: |
9897522 |
Appl. No.: |
09/929446 |
Filed: |
August 14, 2001 |
Current U.S.
Class: |
418/206.1 |
Current CPC
Class: |
F04C 2/086 20130101;
F04C 2/18 20130101 |
Class at
Publication: |
418/206.1 |
International
Class: |
F04C 002/18 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 15, 2000 |
GB |
0019899.4 |
Claims
What is claimed is:
1. An axially compact gear pump comprising a housing and end plate
defining therebetween a gear pumping chamber housing a pair of
meshing gears of the pump wherein: dowel means extend from the
housing through the end plate to locate the end plate relative to
the housing, and project from the end plate for locating the
assembled end plate and housing relative to a drive means in use;
assembly bolts for holding together the end plate and housing prior
to mounting the gear pump on a test plate or on the drive means
extend through the housing and into the end plate; and mounting
bolts for mounting the gear pump on the test plate or the drive
means extend through the housing and end plate and project from the
end plate for connection to the test plate or drive means.
2. A gear pump according to claim 1, wherein the dowel means are
two in number.
3. A gear pump according to claim 2, wherein the assembly bolts are
two in number.
4. A gear pump according to claim 3, wherein the dowel means and
assembly bolts are arranged at the corners of an imaginary
rectangle having the dowel means at opposite corners and the
assembly bolts at opposite corners.
Description
BACKGROUND OF THE INVENTION
[0001] The invention relates to gear pumps for mounting on a drive
means in an axially compact manner.
[0002] Gear pumps are known for mounting on a drive means such as
an engine block of an internal combustion engine or on a hydraulic
piston pump which in turn is mounted on an internal combustion
engine to create an integrated hydraulic package. Such pumps and
pump assemblies are typically used in agricultural tractors or
industrial vehicles which require a regular and reliable source of
hydraulic fluid.
[0003] The design and mounting of conventional gear pumps is as
follows. A housing and an end cap together define a gear pumping
chamber housing a pair of meshing gears of the pump. The end cap is
located on the housing by means of a pair of dowels straddling
aligned blind bores in the housing and end cap, and is secured to
the housing by four bolts passing through the housing and into the
end cap. A pair of flanges extend from opposite sides of the end
cap and each flange is apertured to receive a mounting bolt which
is used to mount the gear pump either onto a test plate for testing
purposes or onto the engine block or hydraulic piston pump for
normal use. The flanged end cap is substantial in size and is
robust so as to maintain the necessary alignment of the gear wheel
axes with the bearings in the housing and with the drive shaft of
the engine. The axial length of the end cap must in essence be
sufficient to withstand the applied loadings in use while
maintaining accurate alignment.
[0004] It is an object of the invention to reduce the axial length
of the gear pump. Simply reducing the axial length of the flanged
end cap is not an acceptable option because of the need to maintain
rigidity in the face of substantial applied loadings.
BRIEF SUMMARY OF THE INVENTION
[0005] The invention provides an axially compact gear pump
comprising a housing and an end plate defining therebetween a gear
pumping chamber housing a pair of meshing gears of the pump
wherein:
[0006] dowel means extend from the housing through the end plate to
locate the end plate relative to the housing, and project from the
end plate for locating the assembled and plate and housing relative
to a drive means in use;
[0007] assembly bolts for holding together the end plate and
housing prior to mounting the gear pump on a test plate or on the
drive means extend through the housing and into the end plate;
and
[0008] mounting bolts for mounting the gear pump on the test plate
or the drive means extend through the housing and end plate and
project from the end plate for connection to the test plate or
drive means.
[0009] The end plate of the pump of the invention is not connected
to the test plate or drive means by means of flanges as in the
prior art pumps. The unique arrangement of dowels and bolts
securing the end plate to the housing and the pump to the test
plate or drive means is sufficient to maintain rigidity of the end
plate both on test and in final use. The test plate or drive means
contributes directly to the rigidity of the end plate and permits
the design of a pump that utilizes an end plate which would not
have sufficient structural rigidity if mounted by conventional
flanges.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a perspective view of a known gear pump
incorporating a flanged end cap;
[0011] FIG. 2 is an axial sectional through the flanged end cap of
FIG. 1;
[0012] FIG. 3 is an end view of the gear pump of FIG. 1, taken from
the mounting end (the left-hand side of FIGS. 1 and 2),
[0013] FIGS. 4a and 4b are schematic side illustrations of a prior
art gear pump (FIG. 4a) and a pump of the invention (FIG. 4b), both
mounted on a closed circuit hydraulic piston pump and on a diesel
engine to illustrate the axially shorter length of the assembly
using a pump according to the invention;
[0014] FIG. 5 is a side elevation of the bellhousing flange/closed
circuit hydraulic piston pump/gear pump subassembly of FIG. 4b;
[0015] FIG. 6 is an end view of the gear pump of FIG. 4b, taken
from the mounting end (the left-hand side of FIG. 4b);
[0016] FIG. 7 is a staggered section taken along the line VII-VII
of FIG. 6;
[0017] FIG. 8 is a side elevation of the pump of FIG. 6;
[0018] FIG. 9 is a plan view of the pump of FIG. 6 mounted on a
test plate, and
[0019] FIG. 10 is an end view of the pump of FIG. 9, taken from the
end remote from the test plate (the right-hand side of FIG. 9).
DETAILED DESCRIPTION OF THE INVENTION
[0020] Referring first to FIGS. 1 to 3, there is illustrated a
conventional known gear pump, which comprises a housing 1 and an
end cap 2 which together house meshing spur gears of the pump (not
shown). The end cap 2 is positioned on the housing 1 by means of
dowels (not shown) which are located in blind bores in the end cap
and housing, straddling the junction between the end cap and
housing. The blind bores in the end cap 2 are identified by
reference numeral 3 in FIG. 2. The end cap 2 is made fast to the
housing 1 by four assembly bolts 4 (FIG. 1) passing through the
housing 1 and into the end cap 2.
[0021] Cast in one piece with the remainder of the end cap 2 are a
pair of flanges 5 which are used to anchor the gear pump to the
engine housing or axial piston pump on which it is to be mounted in
use. Two mounting bolts 6 pass through bores in the flanges 5 to
mount the gear pump on the engine housing or axial piston pump.
FIG. 4a illustrates the total axial length of the assembly of
engine axial piston pump and gear pump.
[0022] FIG. 4b illustrates how an axially more compact mounting is
provided according to the invention. From FIG. 5 it will be seen
that the gear pump 10 of the invention is attached to a closed
circuit hydraulic piston pump 11 which in turn is mounted on the
engine through a conventional bellhousing flange 12.
[0023] Referring to FIGS. 6 to 10, it will be seen that the pump 10
comprises a housing 13 and an end plate 14 which together define a
gear pumping chamber for a pair of meshing gears 15, 16 (FIG. 7) of
the pump. One of the gears, 16, is in the input gear and includes a
splined drive shaft 17 which extends through the end plate 14 to
take a drive input directly from a driven shaft of the engine block
or closed circuit hydraulic piston pump 11.
[0024] Alignment between the housing 13, end plate 14 and hydraulic
piston pump 11 is maintained by a pair of dowels 18 (see FIGS. 7
and 8). Each dowel 18 passes through a through bore in the end
plate 14 and projects from both front and back faces of the end
plate 14. On one side the projecting dowels engage in blind bores
19 of the housing 13. On the other side the dowel 18 engage in
blind bores (not shown) of the closed circuit hydraulic piston pump
11. A pair of assembly bolts 20 (FIG. 10) pass through the housing
13 into screw-threaded engagement with the end plate 14 to hold the
housing 13 and end plate 14 together prior to mounting on an engine
block or on the closed circuit hydraulic piston pump 11. The actual
mounting of the gear pump 10 onto a test plate 21 (FIG. 10) or onto
the closed circuit hydraulic piston pump 11 or onto an engine block
is achieved by means of four heavy duty mounting bolts 22 (FIG. 10)
which pass through pairs of aligned bores in the housing 13 and end
plate 14. One such pair of aligned bores 23 is shown in FIG. 8 in
broken lines.
[0025] Because the mounting bolts 22 serve to augment the clamping
together of the housing 13 and end plate 14. The assembled gear
pump has very high rigidity when mounted either on the test plate
21 (FIG. 10) or on an engine or piston pump (FIG. 4b). The end
plate 14 can therefore be made much less substantial than was
necessary in a conventional prior art pump of FIGS. 1 to 3, and the
axial length of the gear pump can be reduced accordingly.
* * * * *