U.S. patent application number 11/207510 was filed with the patent office on 2007-02-22 for multi-piston pump and valve arrangement.
This patent application is currently assigned to Kelsey-Hayes Company. Invention is credited to Blaise Ganzel.
Application Number | 20070041850 11/207510 |
Document ID | / |
Family ID | 37767485 |
Filed Date | 2007-02-22 |
United States Patent
Application |
20070041850 |
Kind Code |
A1 |
Ganzel; Blaise |
February 22, 2007 |
Multi-piston pump and valve arrangement
Abstract
A multi-piston pump includes a housing defining a first
plurality of N bores therein, where N is the number of bores in the
first plurality. The first plurality of N bores is offset from one
another. The housing defines a second plurality of N bores therein.
The second plurality of N bores is offset from one another. Each
bore of the second plurality of N bores is offset from a
corresponding bore of the first plurality of N bores. A
substantially straight cylindrical piston is disposed in each of
said bores for reciprocal movement along a longitudinal axis
therein. The pistons in the first plurality of N bores are operable
to induce fluid flow in hydraulic fluid. The pistons in the second
plurality
Inventors: |
Ganzel; Blaise; (Ann Arbor,
MI) |
Correspondence
Address: |
MACMILLAN, SOBANSKI & TODD, LLC
ONE MARITIME PLAZA - FOURTH FLOOR
720 WATER STREET
TOLEDO
OH
43604
US
|
Assignee: |
Kelsey-Hayes Company
|
Family ID: |
37767485 |
Appl. No.: |
11/207510 |
Filed: |
August 19, 2005 |
Current U.S.
Class: |
417/273 |
Current CPC
Class: |
F04B 1/053 20130101;
F04B 1/0408 20130101; F04B 1/0421 20130101; B60T 8/341 20130101;
B60T 8/4872 20130101; B60T 8/4031 20130101 |
Class at
Publication: |
417/273 |
International
Class: |
F04B 1/04 20060101
F04B001/04 |
Claims
1. A multi-piston pump comprising: a housing defining a first
plurality of N bores therein, where N is the number of bores in
said first plurality, said first plurality of N bores being offset
from one another, said housing defining a second plurality of N
bores therein, said second plurality of N bores being offset from
one another, each bore of said second plurality of N bores being
offset from a corresponding bore of said first plurality of N
bores; and a non-stepped piston disposed in each of said bores for
reciprocal movement along a longitudinal axis therein, said pistons
in said first plurality of N bores being operable to induce fluid
flow in a first hydraulic circuit, said pistons in said second
plurality of N bores being operable to induce fluid flow in a
second hydraulic circuit.
2. The multi-piston pump of claim 1 wherein said non-stepped piston
includes a valve arrangement for controlling fluid flow in one of
said first hydraulic circuit and said second hydraulic circuit.
3. The multi-piston pump of claim 2 wherein said valve arrangement
includes a check valve.
4. The multi-piston pump of claim 2 wherein said non-stepped piston
is between 5 mm and 6 mm.
5. The multi-piston pump of claim 1 further comprising a generally
cylindrical sleeve disposed in each of said bores, said sleeve
having a substantially straight cylindrical longitudinal cavity
defined therein, wherein said non-stepped piston is a substantially
straight cylindrical piston slidably disposed in said cavity.
6. The multi-piston pump of claim 5 further comprising a clinched
gland sealingly securing said sleeve in said bore.
7. The multi-piston pump of claim 6 further comprising an outlet
check valve formed between said sleeve and said clinched gland,
where in said outlet check valve includes a valve ball and a deep
ball seat formed in said sleeve.
8. The multi-piston pump of claim 1 wherein said first set of N
bores are offset from one another by approximately 360/N degrees,
said second set of N bores are offset from one another by
approximately 360/N degrees, and each bore of said second set of N
bores are offset from a corresponding bore of said first of N bores
set by approximately 90/N degrees.
9. The multi-piston pump of claim 8 wherein N is three.
10. A valve arrangement for controlling fluid flow in a hydraulic
circuit comprising; a main valve body suitable to form a portion of
a multi-piston pump, said main valve body having a plurality of
bores formed therein; and first and second pluralities of
non-stepped pistons disposed in said bores.
11. The valve arrangement of claim 10 wherein a generally
cylindrical sleeve is disposed in each of said bores within said
main valve body, each of said sleeves forming valve seat.
12. The valve arrangement of claim 10 wherein said valve seat forms
a portion of high lift outlet check valve.
13. A multi-piston pump comprising: a housing defining a first set
of N bores therein, where N is the number of bores in said first
set, said first set of N bores being offset from one another, said
housing defining a second set of N bores therein, said second set
of N bores being offset from one another, each bore of said second
set of N bores being offset from a corresponding bore of said first
of N bores set; and a non-stepped piston disposed in each of said
bores for reciprocal movement along a longitudinal axis therein,
said pistons in said first set of N bores being operable to induce
fluid flow in a first hydraulic circuit, said pistons in said
second set of N bores being operable to induce fluid flow in a
second hydraulic circuit; and a valve arrangement for controlling
fluid flow in at least one of the first hydraulic circuit and the
second hydraulic circuit, the valve arrangement including a main
valve body suitable to form a portion of a multi-piston pump.
14. A multi-piston pump comprising: a housing defining a first
plurality of N bores therein, where N is the number of bores in
said first plurality, said first plurality of N bores being offset
from one another, said housing defining a second plurality of N
bores therein, said second plurality of N bores being offset from
one another, each bore of said second plurality of N bores being
offset from a corresponding bore of said first plurality of N
bores; and a non-stepped piston disposed in each of said bores for
reciprocal movement along a longitudinal axis therein, said pistons
in said first plurality of N bores being operable to induce fluid
flow of hydraulic fluid, said pistons in said second plurality of N
bores being operable to induce fluid flow of hydraulic fluid.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates in general to hydraulic pumps.
[0003] 2. Description of Related Art
[0004] A hydraulic brake system is one type of generally known
brake system for vehicles. A vehicle hydraulic brake system
typically has a master cylinder, a number of wheel brake cylinders,
and a hydraulic pump with which brake fluid can be delivered from
the master cylinder to the wheel brake cylinders. For example, the
hydraulic pump may be used for hydraulic brake boosting. The
hydraulic pump may also be used, in conjunction with a series of
valves in a hydraulic control unit (HCU) for antilock braking
system (ABS), traction control (TC), and vehicle stability control
(VSC) functions. One known method for carrying out these functions
is to program an electronic control unit (ECU) to reduce pressure
in the wheel brake cylinders by way of controlling (solenoid)
valves in the HCU. In one known system the intake side of the
hydraulic pump is connected to the wheel brake cylinders and the
pressure side of the hydraulic pump is connected to the master
cylinder. A vehicle hydraulic brake system of this kind has been
disclosed by DE 195 01 760 A1.
[0005] It is generally known to use a dual piston pump for the
hydraulic pump in such a system. The dual piston pump typically
includes pistons disposed opposite each other in a boxer
arrangement, which are driven by a common cam disposed between the
two pistons. The two pistons operate in anti-phase, i.e. while one
of the two pistons is executing a delivery stroke, the other piston
is executing a return stroke. The delivery stroke is the stroke in
which the piston decreases the volume of a displacement chamber in
a cylinder of the piston pump and thus displaces fluid from the
piston pump. In the return stroke, the volume of the displacement
chamber is increased again; this stroke is also often called the
intake stroke. Due to their oscillating operation, piston pumps
have an oscillating intake volume flow and cause pressure
pulsations on the intake side, which have repercussions on the
master cylinder and produce an unpleasant sensation in a foot brake
pedal and generate clearly audible noise. Both of these are
undesirable, particularly if the hydraulic pump is used for
hydraulic brake boosting, i.e. is operated with each braking
maneuver. These are also undesirable during antilock braking,
traction control, and vehicle stability control. Therefore, it is
desirable to reduce the pressure pulsations. It is also known to
embody the pistons of the piston pump as stepped pistons which have
the advantage of aspirating brake fluid during both the delivery
stroke and the return stroke. A stepped piston has the advantage
over a simple piston of a more uniform intake volume flow with a
reduced amplitude and a doubled frequency. U.S. Pat. No. 6,446,435
describes a motor driven pump using an even number of stepped
pistons to reduce amplitudes of pressure pulsations in the inlet of
the pump.
[0006] In operation of the pump, it is desirable that the pump be
reliable, relatively low cost to manufacture, operate with low
noise and vibration, and minimize pressure pulsations in the brake
system that are felt by the driver of the vehicle.
BRIEF SUMMARY OF THE INVENTION
[0007] This invention relates in general to hydraulic pumps and
more specifically to a multi-piston hydraulic pump and a valve
arrangement.
[0008] A first aspect of the present invention includes a
multi-piston pump includes a housing defining a first plurality of
N bores therein, where N is the number of bores in the first
plurality. The bores of the first plurality of N bores are offset
from one another. The housing defines a second plurality of N bores
therein. The bores of the second plurality of N bores are offset
from one another. Each bore of the second plurality of N bores is
also offset from a corresponding bore of the first plurality of N
bores. A substantially straight cylindrical piston is disposed in
each of said bores for reciprocal movement along a longitudinal
axis therein. The pistons in the first plurality of N bores are
operable to induce fluid flow in a first hydraulic circuit. The
pistons in the second plurality of N bores are operable to induce
fluid flow in a second hydraulic circuit.
[0009] In another aspect of the present invention, a valve
arrangement includes a main valve body having a plurality of bores
formed therein. The valve arrangement is suitable to form a portion
of a multi-piston pump and includes first and second pluralities of
non-stepped pistons disposed in the bores. The valve arrangement is
suitable for controlling fluid flow in a hydraulic circuit.
[0010] Various objects and advantages of this invention will become
apparent to those skilled in the art from the following detailed
description of the preferred embodiment, when read in light of the
accompanying drawings.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0011] FIG. 1 is a schematic circuit diagram of a vehicular brake
system.
[0012] FIG. 2 is a schematic representation of a six-piston pump in
accordance with the present invention suitable for use in the
vehicular brake system shown in FIG. 1.
[0013] FIG. 3 is a cross-sectional view of a portion of the pump of
FIG. 2 taken along line 3-3.
[0014] FIG. 4 is an enlarged view of a portion of FIG. 3.
[0015] FIG. 5 is a top view of the sleeve of FIGS. 3 and 5.
[0016] FIG. 6 is a cross-sectional view of the sleeve of FIG. 5
taken along line 6-6
[0017] FIG. 7 is an enlarged view of a portion of FIG. 6 as
indicated at circle 7.
DETAILED DESCRIPTION OF THE INVENTION
[0018] A vehicular brake system is indicated generally at 10 in
FIG. 1. The system 10 includes valves and other components
described below suitable to provide anti-lock braking (ABS),
traction control (TC), and vehicle stability control (VSC)
functions.
[0019] In the system 10, a brake pedal 12 is connected to a master
cylinder 14 to provide pressurized brake fluid to wheel brakes 16.
The master cylinder 14 is in fluid communication with a master
cylinder brake fluid reservoir 15. The reservoir 15 is a source of
bake fluid for the master cylinder 14.
[0020] A hydraulic control unit (HCU) 18 includes a housing having
bores for receiving control valves and other components described
below. Fluid passageways or conduits are provided between the bores
to provide fluid communication between the valves and other
components.
[0021] The HCU 18 includes normally open control valves 20,
commonly referred to as apply valves, disposed between the master
cylinder 14 and the wheel brakes 16. Each apply valve 20 is
preferably formed as a solenoid valve switchable between two
positions. The apply valve 20 includes a coil subassembly that
creates an electromagnetic flux to slide an internal armature
between the two positions.
[0022] The HCU 18 also includes normally closed control valves 22,
commonly known as dump valves, disposed between the wheel brakes 16
and the master cylinder brake fluid reservoir 15. Each dump valve
22 is preferably formed as a solenoid valve switchable between two
positions. The dump valve 22 includes a coil subassembly that
creates an electromagnetic flux to slide an internal armature
between the two positions.
[0023] An isolation valve 28 is provided in each circuit. The
isolation valves 28 are in fluid communication with the master
cylinder brake fluid reservoir 15 and the apply valves 20. The
valves 28 each include a coil subassembly that creates an
electromagnetic flux to slide an internal armature between two
positions.
[0024] A supply valve 30 is provided in each circuit. The supply
valves 30 are in fluid communication with the master cylinder 14
and the control valves 22. The valves 30 each include a coil
subassembly that creates an electromagnetic flux to slide an
internal armature between two positions.
[0025] The system 10 of FIG. 1 is illustrated as a diagonally split
system, wherein the right front wheel RF and the left rear wheel LR
are included in a first circuit I, and the left front wheel LF and
the right rear wheel RR are included in a second circuit II. Other
configurations of the braking system 10 can be provided.
[0026] The valves 20, 22, 28, and 30 are electrically connected to
an electronic control unit 27 and operated to provide desired ABS,
TC, and VSC functions in a well known manner.
[0027] The brake system 10 includes a pump 166 that supplies
pressurized fluid to the brake system 10 during, for example, ABS,
TC, and VSC functions. The pump 166 is driven by a motor 48 in a
well known manner. Preferably, the motor 48 is an electric motor,
for example a flux switching motor. It must be understood, however
that the motor 48 may be any suitable motor.
[0028] Referring to FIG. 2, the pump 166 is illustrated as a
six-piston pump and is suitable for use in the vehicular brake
system 10. It must be understood, however, that the pump 166 may be
a pump with any suitable number of pistons. For example, the
multi-piston pump 166 may be a pump with any suitable even number
of pistons, as will be described below.
[0029] The multi-piston pump 166 includes a main pump housing 130.
The main pump housing 130 is preferably made of a metal, such as
aluminum or any other suitable metal. However, it must be
understood that the main pump housing 130 may be made of any
suitable material. The main pump housing 130 includes a plurality
of bores 132 formed generally in a star shape, meaning that the
bores 132 radiate in a plane from a single point. The main pump
housing 130 is illustrated as including six bores 132. It must be
understood, however, that similar to the number of pistons in the
multi-piston pump 166, the main pump housing 130 may include any
suitable number of bores. For example, the main pump housing 130
may include any suitable even number of bores, as will be described
below.
[0030] The bores 132 are disposed about and extend perpendicularly
from a central bore 133. A cam element 70 that can be driven to
rotate by the pump motor 48 is disposed in the central bore 133. As
illustrated in FIG. 2, the bores 132 are formed in the main pump
housing 130 around the central bore 133 each at a respective angle
of 0 degrees, 30 degrees, 120 degrees, 150 degrees, 240 degrees,
and 270 degrees. It must be understood, however, that the bores may
be formed at any suitable angle, as will be described below.
[0031] The bores 132 are preferably each formed with a plurality of
stepped sections that have successively more reduced diameters
toward the interior (i.e., center) of the housing 130 (or near to
the motor 48 and the cam 70), i.e., the sections of the bore 132
closest to the central bore 133 have a smaller diameter than the
adjacent segment further away form the central bore 133. It must be
understood, however, that the bores need not necessarily include
stepped section and, indeed, may have any suitable form.
[0032] The main pump housing 130 includes a plurality of inlet
ports 134 and outlet ports 136 formed therein. Each bore 132 is in
fluid communication with a respective inlet port 134 and a
respective outlet port 136. As shown, the inlet ports 134 of the
bores 132 at 0 degrees, 120 degrees, and 240 degrees are connected
to the first circuits I. As also shown, the outlet ports 136 of the
bores 132 at 0 degrees, 120 degrees, and 240 degrees are connected
to the first circuits I. Similarly, the inlet ports 134 and the
outlet ports 136 of the bores 132 at 30 degrees, 150 degrees, and
270 degrees are connected to the second circuit II. Thus, the bores
132 alternately form portions of the first and second circuits I
and II.
[0033] As best shown in FIG. 3, the multi-piston pump 166 further
includes a plurality of piston/cylinder arrangements 140, one
piston/cylinder arrangement 140 disposed in each of the bores 132.
The piston/cylinder arrangements 140 thereby have an alternating
phase shift of 30 degrees and 90 degrees.
[0034] As illustrated in FIG. 3, the piston/cylinder arrangement
140 includes a generally cylindrical sleeve 142, a clinched gland,
i.e., plug, 144, and a non-stepped piston 168. However, it must be
understood that the piston/cylinder arrangement 140 may be any
suitable piston/cylinder arrangement.
[0035] The sleeve 142 is a substantially straight cylindrical
sleeve that sealingly engages the bore 132. The sleeve 142 is
essentially a cylinder with a pair of seals that separate portions
of the bore 132 as to isolate the inlet and outlet ports 134 and
136 from each other. The sleeve 142 is a simplified sleeved design
as compared to the sleeves of previous multi-piston pumps. The
simplified design provides for reduced costs in manufacturing. The
simplified sleeve design of the sleeve 142 allows for a reduced
piston size while permitting 30 degree spacing between the sleeves
142, and while maintaining desired packaging size of the housing
130. It must be understood, however, that the sleeve 142 may be ay
suitable sleeve.
[0036] Each cylindrical sleeve 142 is disposed in a respective bore
132 and sealed in position by a respective clinched gland 144. The
use of the clinched gland 144 reduces production costs as compared
to other means for securing the sleeve 142 in the bore 132.
Further, as compared to other types of securing means the clinched
gland 144 secures the sleeve 142 in the bore 132 without distorting
the bore 132. It must be understood, however, that sealing/securing
mechanism may be used, such as a threaded arrangement, weld, or any
other suitable mechanism.
[0037] Each non-stepped piston 168 is disposed in a respective
generally cylindrical sleeve 142. The piston 168 is a non-stepped
piston, i.e., a substantially straight cylindrical piston, for
reciprocal movement along a longitudinal axis. The piston 168 is
operable to induce fluid flow in a hydraulic circuit. While the
piston 168 may be any suitable size, the piston 168 is most
preferably a piston sized between 5 and 6 millimeters.
[0038] The multi-piston pump 166 includes an inlet check valve
arrangement 150 and an outlet check valve arrangement 152
associated with a respective piston/cylinder arrangement 140. As
shown in FIG. 3, the inlet check valve arrangement 150 is
preferably included within the non-stepped piston 168 and is
suitable to control fluid flow in one of the first hydraulic
circuit and the second hydraulic circuit. It must be understood,
however, that the multi-piston pump 166 may include any suitable
inlet control valve, in any suitable configuration.
[0039] The outlet check valve 152 is formed between the sleeve 142
and the clinched gland 144. The outlet check valve 152 includes a
valve ball 154 and a deep ball seat 156 formed in the sleeve 142.
Due to the deep ball seat 156 the valve ball 154 will travel
significantly when transitioning from a closed position of the seat
156 to an open position above the seat 156. The outlet check valve
152 is thus a high lift outlet check valve. The high lift aspects
of the outlet check valve 152 minimizes noise as compared to
previous pumps when the pump is run at reduced speed/low output
flow.
[0040] The use of the inlet check valve 150 and the outlet check
valve 152 minimizes the unswept pump chamber volume as compared to
previous designs and allows for the use of the non-stepped piston
168 in the piston/cylinder arrangement 140.
[0041] The multi-piston pump 166 includes six non-stepped pistons
168 alternating in two sets of three, one set of pistons 168 offset
from the other set of pistons 168 by 30 degrees.
[0042] As shown in FIG. 2, the six non-stepped pistons 168 are
disposed in the bores 132 around the cam element 70. The
non-stepped pistons 168 are shown disposed at angles of 0 degrees,
30 degrees, 120 degrees, 150 degrees, 240 degrees, and 270 degrees.
As illustrated, the non-stepped pistons 168 thereby have an
alternating phase shift of 30 degrees and 90 degrees. A first set
of three non-stepped pistons 168 offset from one another by 120
degrees are hydraulically connected to one another in parallel and
are associated with the first brake circuit I. The remaining three
non-stepped pistons 168, which are offset from one another by 120
degrees similar to the first set, form a second set of three
non-stepped pistons 168 that is offset from the first set of three
non-stepped pistons 168 by 30 degrees. Similar to the non-stepped
pistons 168 of the first set and the first circuit, the non-stepped
pistons 168 of the second set are likewise hydraulically connected
to one another in parallel, and connected to the second brake
circuit II. The three non-stepped pistons 168 of the first set are
offset from one another by 120 degrees and are also offset from the
three non-stepped pistons 168 of the second set by 30 degrees.
[0043] In principle, the phase shifting of the six non-stepped
pistons 168 by 30 degrees and 90 degrees produces a compensation
effect of the pressure pulsations on the intake sides of the
non-stepped pistons 168. The total intake volume flow, i.e., the
sum of all six intake volume flows, has a significantly reduced
fluctuation amplitude in comparison to a six-piston pump with
pistons, stepped or non-stepped, that are each uniformly offset
from on another by 60 degrees. The use of the non-stepped pistons
168 and their alternating disposition offset from one another by 30
degrees and 90 degrees results in a uniform phase shifting of the
intake volume flows by 30 degrees in relation to one another.
Whereas, in the case of a uniformly distributed disposition of
pistons, for example, six pistons offset by 60 degrees, the intake
volume flows of opposing pistons 168 travel in anti-phase with each
other without a phase shift; and in sum, result in intake volume
flows with twice the amplitude of the six intake volume flows of
the six-piston pump shown in FIG. 2.
[0044] While the multi-piston pump 166 has been described with six
non-stepped pistons, it must be understood that the present
invention contemplates a variety of multi-piston pumps including a
variety of numbers of non-stepped pistons. For example, the present
invention includes a multi-piston pump having a housing defining a
first set of N bores therein, where N is the number of bores in the
first set. The first set of N bores are offset from (i.e., not
aligned with) one another. The housing also defines a second set of
N bores therein. The bores in the second set of N bores are offset
from one another. Each bore of the second set of N bores is offset
from a corresponding bore of the first of N bores set. While some
configurations are more preferred over others, one such
configuration is described above, it must be understood that any
configuration where the spacing between the bores is not 360/2N
degrees in sufficiently offset. One multi-piston pump, with a
preferred configuration includes a first set of N bores offset from
one another by approximately 360/N degrees and a second set of N
bores offset from one another by approximately 360/N degrees with
each bore of the second set being offset from a corresponding bore
of the first set by approximately 90/N degrees. In such a pump a
preferred number N is three. It must be understood however that N
may be any suitable number.
[0045] The principle and mode of operation of this invention have
been explained and illustrated in its preferred embodiment.
However, it must be understood that this invention may be practiced
otherwise than as specifically explained and illustrated without
departing from its spirit or scope.
* * * * *