U.S. patent application number 17/557126 was filed with the patent office on 2022-06-23 for reciprocating piston lubrication pump.
The applicant listed for this patent is Aktiebolaget SKF, SKF Lubrication Systems Germany GmbH. Invention is credited to Azeez Abdul, Thomas Eichhorn, Mohammed Faid, Christine Matta, Tobias Mueller, Ileana Nedelcu, Heinz Ruhl, Gunther Wenskat, Xiaobo Zhou.
Application Number | 20220196002 17/557126 |
Document ID | / |
Family ID | 1000006092916 |
Filed Date | 2022-06-23 |
United States Patent
Application |
20220196002 |
Kind Code |
A1 |
Zhou; Xiaobo ; et
al. |
June 23, 2022 |
RECIPROCATING PISTON LUBRICATION PUMP
Abstract
A reciprocating piston lubrication pump with a component is
proposed having an opening, which has at least one cylinder-shaped
part, and with at least one piston, which comprises a radially
outer surface built at least partly by a coating. A clearance
between the radially outer surface of the piston and the component
is between 1 .mu.m and 20 .mu.m when the radially outer surface is
positioned in the cylinder-shaped part. The surface hardness of the
coating at the radially outer surface is 2 to 10 times higher than
that of a region of the component, which forms the cylinder-shaped
part.
Inventors: |
Zhou; Xiaobo; (Houten,
NL) ; Mueller; Tobias; (Kraichtal, DE) ;
Abdul; Azeez; (Utrecht, NL) ; Ruhl; Heinz;
(Ubstadt-Weiher, DE) ; Matta; Christine; (Utrecht,
NL) ; Faid; Mohammed; (Vleuten, NL) ; Nedelcu;
Ileana; (Nieuwegein, NL) ; Eichhorn; Thomas;
(Lustadt, DE) ; Wenskat; Gunther; (Otterberg,
DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Aktiebolaget SKF
SKF Lubrication Systems Germany GmbH |
Goteborg
Walldorf |
|
SE
DE |
|
|
Family ID: |
1000006092916 |
Appl. No.: |
17/557126 |
Filed: |
December 21, 2021 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F04B 15/02 20130101;
F04B 53/18 20130101; F04B 19/22 20130101 |
International
Class: |
F04B 19/22 20060101
F04B019/22; F04B 53/18 20060101 F04B053/18; F04B 15/02 20060101
F04B015/02 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 22, 2020 |
DE |
102020134539.9 |
Claims
1. A reciprocating piston lubrication pump with a component
comprising: an opening, which has at least one cylinder-shaped
part, and with at least one piston, which comprises a radially
outer surface built at least partly by a coating, wherein a
clearance between the radially outer surface of the piston and the
component is between 1 .mu.m and 20 .mu.m when the radially outer
surface is positioned in the cylinder shaped part, and wherein the
surface hardness of the coating at the radially outer surface is 2
to 10 times higher than that of a region of the component, which
forms the cylinder-shaped part.
2. The reciprocating piston lubrication pump according to claim 1,
wherein at least the region of the component consists of a steel,
which comprises 0.8 to 1.5 weight percent of Carbon, 4.0 to 5.0
weight percent of Chromium, 1.5 to 4.5 weight percent of Vanadium,
5.5 to 6.5 weight percent of Tungsten and 4.5 to 5.5 weight percent
of Molybdenum and 0.1 to 0.5 weight percent of Silicon.
3. The reciprocating piston lubrication pump according to claim 1,
wherein at least the region of the component is hardened to a
hardness of 700 to 900 HV at room temperature and/or to an
unnotched Izod toughness of 35 to 80 J at room temperature.
4. The reciprocating piston lubrication pump according to claim 1,
wherein a radially inner surface of the region of the component is
machined to a roughness R.sub.z=2 to 6 .mu.m.
5. The reciprocating piston lubrication pump according to claim 1,
wherein at least a part of the coating consists of titanium
carbonitride and/or TiAlSiN and/or TiSiN and/or AlCrN.
6. The reciprocating piston lubrication pump according to claim 1,
wherein the coating has a thickness between 1 and 12 .mu.m.
7. The reciprocating piston lubrication pump according to claim 1,
wherein at least a base body of the piston consists of steel, which
comprises 0.8 to 1.0 weight percent of Carbon, 4.0 to 4.5 weight
percent of Chromium, 1.5 to 2.5 weight percent of Vanadium, 5.5 to
6.5 weight percent of Tungsten and 4.5 to 5.5 weight percent of
Molybdenum and 0.1 to 0.5 weight percent of Silicon.
8. The reciprocating piston lubrication pump according to claim 1,
wherein the piston comprises a hardness between 650 and 850 HV at
room temperature and/or an unnotched Izod toughness between 50 and
80 J at room temperature.
9. The reciprocating piston lubrication pump according to claim 1,
wherein the coating is machined to a roughness R.sub.z=1 to 5
.mu.m.
10. The reciprocating piston lubrication pump according to claim 1,
wherein a critical load L.sub.c of the coating and/or an adhesion
of the coating to a base body of the piston is equal or higher than
30 N measured according to the standard ISO 20502 and/or according
to the standard EN 1071-3 and/or according to the standard ASTM
C1624.
11. A device with a reciprocating piston lubrication pump
comprising: a reciprocating piston lubrication pump with a
component comprising: an opening, which has at least one
cylinder-shaped part, and with at least one piston, which comprises
a radially outer surface built at least partly by a coating,
wherein a clearance between the radially outer surface of the
piston and the component is between 1 .mu.m and 20 .mu.m when the
radially outer surface is positioned in the cylinder shaped part,
and wherein the surface hardness of the coating at the radially
outer surface is 2 to 10 times higher than that of a region of the
component, which forms the cylinder-shaped part, wherein the
reciprocating piston lubrication pump contains a lubricant with
more than 34 weight percent of oils and less than 60 weight
percent, preferably less than 50 weight percent and more preferably
less than 40 weight percent of oils.
12. The device, in particular according to claim 11, wherein the
reciprocating piston lubrication pump contains a lubricant with
more than 10 weight percent, preferably more than 18 weight percent
and more preferably more than 25 weight percent of metallic
particles.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to German Patent
Application no. 102020134539.9, filed Dec. 22, 2020, the contents
of which is fully incorporated herein by reference.
FIELD OF THE INVENTION
[0002] This invention relates to a reciprocating piston lubrication
pump with a component having an opening. This invention further
relates to a reciprocating piston lubrication pump with a component
having an opening that provides at least one cylinder-shaped part,
and with at least one piston, which comprises a radially outer
surface built at least partly by a coating.
BACKGROUND OF THE INVENTION
[0003] Lubrication pumps play a major role in lubrication systems.
There are many different types of lubrication pumps such as
reciprocating piston pump, rotary pump (screw, gear pumps, rotary
vane and lobe pumps), eddy (slurry) pumps, etc. aiming for
different application purposes. The reciprocating piston pump is
one of the most often used pumps due to its compactness and
precision of lubricant delivery. The lubrication pump can be used
to deliver complicated lubricants to provide combination effects of
anti-friction, anti-noise and even a sealing effect in the
applications such as railroad, tunnel boring, mining, et al. To
achieve the desired functions, the special lubricants however
consist of a large amount of metallic particles, up to 30 wt % in
total, in which iron, aluminum, copper and magnesium are the major
compositions. In some cases, the lubricant may also have very low
oil content, down to 35 wt %. The high content of the metallic
particles and/or the low concentration of oils in the lubricants
may accelerate the wear and induce local fracture of the pump
components, i.e., pump piston and pump cylinder, and reduce the
pump service life significantly. In some extreme cases, the pump
may fail in few weeks and even in few days.
[0004] From the prior art a reciprocating piston lubrication pump
is known with a valve, a piston and a cylinder, which comprises
suction holes. During operation lubricant flows through the suction
holes inside the cylinder. Afterwards the piston pumps the
lubricant through the valve.
[0005] The task of the invention is in particular to provide a
reciprocating piston lubrication pump with an efficient design and
a high service life.
SUMMARY OF THE INVENTION
[0006] Suggested is a reciprocating piston lubrication pump with a
component comprising an opening, which has at least one
cylinder-shaped part, and with at least one piston, which comprises
a radially outer surface built at least partly by a coating,
wherein a clearance between the radially outer surface of the
piston and the component is between 1 .mu.m and 20 .mu.m,
preferably between 2 .mu.m and 10 .mu.m, when the radially outer
surface is positioned in the cylinder-shaped part, wherein the
surface hardness of the coating at the radially outer surface is 2
to 10 times higher, preferably 4 to 8 times higher, than that of a
region of the component, which forms the cylinder-shaped part.
Through this an efficient design and a high service life can be
achieved. In particular little wear and little occurrence of
fracture damage during operation, in particular for lubricants with
a high percentage of metallic particles and/or low oil content, can
be attained for relatively low costs.
[0007] Preferably at least the region of the component consists of
a steel, which comprises 0.8 to 1.5 weight percent of Carbon, 4.0
to 5.0 weight percent of Chromium, 1.5 to 4.5 weight percent of
Vanadium, 5.5 to 6.5 weight percent of Tungsten and 4.5 to 5.5
weight percent of Molybdenum and 0.1 to 0.5 weight percent of
Silicon. By this a high hardness of the region can be achieved in a
cost efficient way.
[0008] Furthermore, it is suggested that at least the region of the
component is hardened to a hardness of 700 to 900 HV, preferably of
750 HV to 850 HV, at room temperature and/or to an unnotched Izod
toughness of 35 to 80 J, preferably of 50 to 70 J, at room
temperature. The unnotched Izod toughness is the physical quantity
measured according to the Standard D4812-19 of the American Society
for Testing and Materials. Alternatively, a quantification could be
given through the standard ISO 180. In combination with the
hardness of the piston this minimizes the wear for lubricants with
many metallic particles and a low oil content.
[0009] With advantage a radially inner surface of the region of the
component is machined to a roughness R.sub.z=2 to 6 .mu.m. This
implies a low friction with the piston and can be achieved in a
cost saving manner.
[0010] Moreover, it is suggested that the coating is created by
Physical Vapor Deposition and/or Chemical Vapor Deposition in a low
vacuum chamber, which ensures an easy produceability.
[0011] Preferably at least a part of the coating consists of
titanium carbonitride. Advantageously in this case the hardness is
2000 to 5000 HV, more preferably between 3000 and 4000 HV.
[0012] Moreover, it is suggested that at at least a part of the
coating consists of TiAlSiN and/or TiSiN and/or AlCrN.
Advantageously in this case the hardness is 3000 to 6000 HV,
preferably between 4000 and 5500 HV.
[0013] Preferably the coating has a thickness between 1 and 12
.mu.m and more preferably between 2 .mu.m and 6 .mu.m.
[0014] With advantage at least a part of the piston consists of
steel, which comprises 0.8 to 1.0 weight percent of Carbon, 4.0 to
4.5 weight percent of Chromium, 1.5 to 2.5 weight percent of
Vanadium, 5.5 to 6.5 weight percent of Tungsten and 4.5 to 5.5
weight percent of Molybdenum and 0.1 to 0.5 weight percent of
Silicon. Thereby the required hardness can be achieved very
economically.
[0015] Moreover, it is suggested that the piston comprises a
hardness between 650 and 850 HV, preferably between 700 HV and 800
HV, at room temperature and/or an unnotched Izod toughness between
50 and 80 J, preferably between 60 and 70 J, at room temperature.
In combination with the hardness of the region of the component
this minimizes the wear for lubricants with many metallic particles
and a low oil content.
[0016] The piston can be hardened and tempered at temperatures
between 450 and 600.degree. C.
[0017] Preferably a base body of the piston retains dimensional
stability up to 500.degree. C., which implies that it is tolerant
to the thermal impact during the coating deposition process.
[0018] Advantageously the coating is machined to a roughness
R.sub.z=1 to 5 .mu.m. This implies a low friction with the piston
and can be achieved in a cost saving manner.
[0019] Moreover, it is suggested that the piston is made of a high
carbon and low alloyed steel, which can retain the dimensional
stability up to 500.degree. C. Preferably a critical load L.sub.c
of the coating and/or an adhesion of the coating to a base body of
the piston is equal or higher than 30 N, preferably higher than 50
N, measured according to the standard ISO 20502 and/or according to
the standard EN 1071-3 and/or according to the standard ASTM C1624.
By this a high resistibility in particular against metallic
particles in the lubricant can be attained.
[0020] There can be a chamfer on the piston front. The angle of the
chamfer can be 15 to 75.degree. and preferably 30 to 60.degree.,
the length of the chamfer can be 0.2 to 4 mm, preferably 0.5 to 2
mm A minimization of negative interaction with metallic particles
of the lubricant can be attained. A surface roughness on the
chamfer can be R.sub.z=1 to 6 .mu.m.
[0021] Furthermore, a device with the reciprocating piston
lubrication pump is suggested, wherein the reciprocating piston
lubrication pump contains a lubricant with more than 34 weight
percent of oils and less than 60 weight percent, preferably less
than 50 weight percent and more preferably less than 40 weight
percent, of oils. Thereby a long service life of the reciprocating
piston lubrication pump can be achieved despite the special kind of
lubricant.
Furthermore, a device with the reciprocating piston lubrication
pump is suggested, wherein the reciprocating piston lubrication
pump contains a lubricant with more than 10 weight percent,
preferably more than 18 weight percent and more preferably more
than 25 weight percent of metallic particles. Thereby a long
service life of the reciprocating piston lubrication pump can be
achieved despite the special kind of lubricant.
BRIEF DESCRIPTION OF THE FIGURES
[0022] Further advantages result from the following drawing
description. The drawings show an embodiment of the invention. The
drawings, the description and the claims contain numerous features
in combination. It is advisable for the person skilled in the art
to consider the features individually and to combine them into
meaningful further combinations.
[0023] FIG. 1 shows an axial local section of a reciprocating
piston lubrication pump according to the invention,
[0024] FIG. 2 shows an axial section of a component of the
reciprocating piston lubrication pump,
[0025] FIG. 3 shows a side view of a piston of the reciprocating
piston lubrication pump,
[0026] FIG. 4 shows a view on the component in axial direction.
DETAILED DESCRIPTION OF THE INVENTION
[0027] FIG. 1 shows an axial local section of a reciprocating
piston lubrication pump 10 according to the invention, which
comprises component 12 with an opening 14 (FIG. 2). The opening 14
has a cylinder-shaped part 16. A piston 18 of the reciprocating
piston lubrication pump 10 is located partly within a region 24 of
the component, which forms the cylinder-shaped part 16. The piston
18 has a radially outer surface 20 which is built by a coating 22.
A clearance between the radially outer surface of the piston and
the component is between two and 10 micrometers when the radially
outer surface is located in the cylinder-shaped part. A surface
hardness of the coating at the radially outer surface is four to
eight times higher than that of the region of the component which
forms the cylinder-shaped part.
[0028] The component comprises a hole 30 (FIG. 1) and a further
hole (not shown) through which lubricant (not shown) is sucked into
a part of the opening, which is located between the piston and a
valve 26 of the reciprocating lubrication pump, when the piston is
moving away from the valve during operation. Afterwards the piston
is moving towards the valve 26 and causes the lubricant to be
pressed through the valve and afterwards through a hole 32 (FIG. 2)
of the component 12. The valve 26 is a check valve. When the piston
is moved fully towards the valve 26 a spring 28 of the
reciprocating lubrication pump 10 pushes the piston back and away
from the valve 26.
[0029] In different embodiments the component can have different
numbers of holes through which lubricant is sucked in, e. g. three
or four.
[0030] The component consists of a steel, which comprises 0.8 to
1.5 weight percent of Carbon, 4.0 to 5.0 weight percent of
Chromium, 1.5 to 4.5 weight percent of Vanadium, 5.5 to 6.5 weight
percent of Tungsten and 4.5 to 5.5 weight percent of Molybdenum and
0.1 to 0.5 weight percent of Silicon. Furthermore, the region of
the component is hardened to a hardness of 750 to 850 HV at room
temperature and to an unnotched Izod toughness of 50 to 70 J at
room temperature. A radially inner surface of the region of the
component is machined to a roughness R.sub.z=2 to 6 .mu.m.
[0031] The coating 22 of the piston consists of titanium
carbonitride and has a thickness between 2 and 6 .mu.m. The piston
consists of a base body and the coating. The base body of the
piston consists of steel, which comprises 0.8 to 1.0 weight percent
of Carbon, 4.0 to 4.5 weight percent of Chromium, 1.5 to 2.5 weight
percent of Vanadium, 5.5 to 6.5 weight percent of Tungsten and 4.5
to 5.5 weight percent of Molybdenum and 0.1 to 0.5 weight percent
of Silicon.
[0032] The base body of the piston comprises a hardness between 700
and 800 HV at room temperature and an unnotched Izod toughness
between 60 and 70 J at room temperature. The coating comprises a
hardness between 3000 HV and 4000 HV. The radially outer surface of
the piston, which is built by the coating, has a roughness R.sub.z
between 1 and 5 .mu.m. A critical load Le of the coating and an
adhesion of the coating to the base body of the piston is equal or
higher than 30 N measured according to the standard ISO 20502.
[0033] During an operation in a device the reciprocating piston
lubrication pump contains a lubricant with more than 34 weight
percent of oils and less than 50 weight percent of oils and with
more than 18 weight percent of metallic particles.
[0034] There is a chamfer 34 on the piston front. The angle of the
chamfer is 30 to 60.degree. measured relative to a central axis 36,
and the length is 0.5 to 2 mm, and the surface roughness on the
chamfer is R.sub.z=1 to 6 .mu.m.
[0035] In comparison to a conventional pump in which the piston and
the cylinder are made of machinable hardened steel, the described
pump, in which the piston and the component are made of the special
steels and coatings, can prolong the pump service life by 4 to 100
times when pumping a special lubricants consisting of high metallic
particles and/or low oil. Abrasive wear and fracture induced by
metallic particles and poor lubrication induced by starved
lubrication due to low oil content on the piston and the surface of
the region can be minimized by the special steels and the coating,
which have higher hardness, high toughness and optimized matching
of the hardness between the piston coating and the surface of the
region of the component.
* * * * *