U.S. patent application number 12/133710 was filed with the patent office on 2008-10-02 for copper-zinc alloy and synchronizer ring produced therefrom.
This patent application is currently assigned to DIEHL METALL STIFTUNG & CO. KG. Invention is credited to Norbert Gaag, Friedrich Gebhard, Meinrad Holderied.
Application Number | 20080240973 12/133710 |
Document ID | / |
Family ID | 37722603 |
Filed Date | 2008-10-02 |
United States Patent
Application |
20080240973 |
Kind Code |
A1 |
Gaag; Norbert ; et
al. |
October 2, 2008 |
Copper-Zinc Alloy and Synchronizer Ring Produced Therefrom
Abstract
A copper-zinc alloy is particularly suitable for forming
synchronizer rings. The novel alloy contains 55 to 75 wt. % copper,
0.1 to 8 wt. % aluminum, 0.3 to 3.5 wt. % iron, 0.5 to 8 wt. %
manganese, 0 to less than 5 wt. % nickel, 0 to less than 0.1 wt. %
lead, 0 to 3 wt. % tin, 0.3 to 5 wt. % silicon, 0 to less than 0.1
wt. % cobalt, 0 to less than 0.05 wt. % titanium, 0 to less than
0.02 phosphorus, unavoidable impurities and the remainder zinc.
Inventors: |
Gaag; Norbert; (Lauf,
DE) ; Holderied; Meinrad; (Igensdorf, DE) ;
Gebhard; Friedrich; (Lauf/Peg, DE) |
Correspondence
Address: |
LERNER GREENBERG STEMER LLP
P O BOX 2480
HOLLYWOOD
FL
33022-2480
US
|
Assignee: |
DIEHL METALL STIFTUNG & CO.
KG
Rothenbach
DE
|
Family ID: |
37722603 |
Appl. No.: |
12/133710 |
Filed: |
June 5, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/EP2006/011622 |
Dec 5, 2006 |
|
|
|
12133710 |
|
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Current U.S.
Class: |
420/480 |
Current CPC
Class: |
C22F 1/08 20130101; C22C
9/01 20130101; C22C 9/05 20130101; C22F 1/00 20130101; F16D 23/025
20130101; C22C 9/04 20130101; F16H 3/12 20130101 |
Class at
Publication: |
420/480 |
International
Class: |
C22C 9/04 20060101
C22C009/04 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 13, 2005 |
DE |
10 2005 059 391.7 |
Claims
1. A copper-zinc alloy, comprising: 55 to 75 wt. % copper; 0.1 to 8
wt. % aluminum; 0.3 to 3.5 wt. % iron; 0.5 to 8 wt. % manganese; 0
to less than 5 wt. % nickel; 0 to less than 0.1 wt. % lead; 0 to 3
wt. % tin; 0.3 to 5 wt. % silicon; 0 to less than 0.1 wt. % cobalt;
0 to less than 0.05 wt. % titanium; 0 to less than 0.02 wt. %
phosphorus; unavoidable impurities; and a remainder zinc.
2. The copper-zinc alloy according to claim 1, which contains
nickel in an amount of less than 5 wt. % nickel, lead in an amount
of less than 0.1 wt. %, tin in an amount of up to 3 wt. %, cobalt
in an amount of less than 0.1 wt. %, titanium in an amount of less
than 0.05 wt. %, and phosphorus in amount of less than 0.02 wt.
%.
3. The copper-zinc alloy according to claim 1, which contains
aluminum in a proportion of from 0.5 to 2.5 wt. %, iron in a
proportion of from 0.3 to 1 wt. %, manganese in a proportion of
from 0.5 to 5 wt. %, nickel in a proportion of from 0.5 to less
than 5 wt. %, tin in a proportion of from 0 to 1.5 wt. %, and
silicon in a proportion of from 0.3 to 2 wt. %.
4. The copper-zinc alloy according to claim 1, which contains
aluminum in a proportion of from 3 to 8 wt. %, iron in a proportion
of from 1 to 3 wt. %, manganese in a proportion of from 5 to 8 wt.
%, nickel in a proportion of from 0 to less than 0.5 wt. %, tin in
a proportion of from 0 to less than 0.5 wt. %, and silicon in a
proportion of from 1 to 4 wt. %.
5. The copper-zinc alloy according to claim 1, which contains at
least one of the following components: nickel in an amount of less
than 5 wt. %, lead in an amount of less than 0.1 wt. %, tin in an
amount of up to 3 wt. %, cobalt in an amount of less than 0.1 wt.
%, titanium in an amount of less than 0.05 wt. %, and phosphorus in
amount of less than 0.02 wt. %.
6. The copper-zinc alloy according to claim 1, which contains at
least two of the following components: nickel in an amount of less
than 5 wt. %, lead in an amount of less than 0.1 wt. %, tin in an
amount of up to 3 wt. %, cobalt in an amount of less than 0.1 wt.
%, titanium in an amount of less than 0.05 wt. %, and phosphorus in
amount of less than 0.02 wt. %.
7. The copper-zinc alloy according to claim 1, which contains at
least three of the following components: nickel in an amount of
less than 5 wt. %, lead in an amount of less than 0.1 wt. %, tin in
an amount of up to 3 wt. %, cobalt in an amount of less than 0.1
wt. %, titanium in an amount of less than 0.05 wt. %, and
phosphorus in amount of less than 0.02 wt. %.
8. The copper-zinc alloy according to claim 1, which contains at
least four of the following components: nickel in an amount of less
than 5 wt. %, lead in an amount of less than 0.1 wt. %, tin in an
amount of up to 3 wt. %, cobalt in an amount of less than 0.1 wt.
%, titanium in an amount of less than 0.05 wt. %, and phosphorus in
amount of less than 0.02 wt. %.
9. A synchronizer ring consisting of a copper-zinc alloy according
to claim 1.
10. A method of producing a synchronizer ring, which comprises:
providing a copper-zinc alloy according to claim 1; and forming a
synchronizer ring from the copper-zinc alloy.
11. The method according to claim 10, wherein the forming step
comprises machining the synchronizer ring from the copper-zinc
alloy.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This is a continuing application, under 35 U.S.C. .sctn.
120, of copending international application PCT/EP2006/011622,
filed Dec. 5, 2006, which designated the United States; this
application also claims the priority, under 35 U.S.C. .sctn. 119,
of German patent application No. DE 10 2005 059 391.7, filed Dec.
13, 2005; the prior applications are herewith incorporated by
reference in their entirety.
BACKGROUND OF THE INVENTION
Field of the Invention
[0002] The invention relates to a novel copper-zinc alloy. The
invention also relates to a use of such a copper-zinc alloy for
producing a synchronizer ring, as well as to a synchronizer
ring.
[0003] Copper-zinc alloys or brasses are used in the plumbing and
sanitary industries as well as in the electronics industry. In the
automobile industry, brass rings with a high wear resistance and a
high friction coefficient are employed for synchronizer rings which
are used in a mechanical gearbox for synchronizing the gear
wheel.
[0004] In order to be able to process a copper-zinc alloy easily,
particularly by machining, a certain brittleness of the material
must be achieved in order to avoid as far as possible creating long
swarf during the processing, which would be difficult to transport
away from the workplace and the processing tool. As is known, this
brittleness desired for the mechanical processing of brasses is
achieved by adding a certain proportion of lead. Lead in
corresponding doses, however, disadvantageously represents a hazard
to human health.
[0005] It is therefore desirable to provide mechanically
processable copper-zinc alloys which have as low as possible or
even no lead content. Although various European Union guidelines
still permit the use of lead in brass alloys, it is nevertheless to
be expected that the lead content of up to 4% allowed for brasses
used in motor vehicles will be corrected downwards.
[0006] A lead-free copper-zinc alloy for applications in the
plumbing industry is known from European patent EP 1 045 041 B1 and
U.S. Pat. No. 6,413,330 B1. The disclosed alloy comprises 69 to 79
wt. % copper, 2 to 4 wt. % silicon, 0.1 to 1.5 wt. % aluminum and
0.02 to 0.25 wt. % phosphorus. This interaction of the components
silicon, aluminum and phosphorus is intended to produce a gamma
phase of the alloy, which ensures good machine processability
without using lead.
[0007] Low-lead copper-zinc alloys with a high wear strength for
use in a synchronizer ring are known from the commonly assigned
German patents DE 29 19 478 C2, DE 37 35 783 C1 (cf. U.S. Pat. No.
4,954,187) and European patent EP 0 657 555 B1.
[0008] German patent DE 29 19 478 C2 discloses a copper-zinc alloy
having 70 to 73 wt. % copper, 6 to 8 wt. % manganese, 4 to 6 wt. %
aluminum, 1 to 4 wt. % silicon, 1 to 3 wt. % iron, 0.5 to 1.5 wt. %
lead, 0 to 0.2 wt. % nickel, 0 to 0.2 wt. % tin and zinc as the
remainder. In order to achieve the high wear strength, this alloy
comprises a lattice of 60 to 85% a mixed crystal predominantly as a
finely disperse distribution in the .beta. phase. Lead is alloyed
to it in a relatively small weight proportion.
[0009] German patent DE 37 35 783 C1 and its counterpart U.S. Pat.
No. 4,954,187 describe a copper-zinc alloy to be used particularly
for synchronizer rings, which consists of 50 to 65 wt. % copper, 1
to 6 wt. % aluminum, 0.5 to 5 wt. % silicon, 5 to 8 wt. % nickel as
well as selectively 0 to 1 wt. % iron, 0 to 2 wt. % lead and zinc
as the remainder. A lead proportion of less than 2 wt. % is
optional. The high wear resistance is achieved in that the nickel
is present predominantly as an intermetallic compound with silicon
and aluminum.
[0010] A copper-zinc alloy having high wear resistance is
furthermore known from European patent EP 0 657 555 B1, which
comprises 40 to 65 wt. % copper, 8 to 25 wt. % nickel, 2.5 to 5 wt.
% silicon, 0 to 3 wt. % aluminum, 0 to 3 wt. % iron, 0 to 2 wt. %
manganese, 0 to 2 wt. % lead, the remainder being zinc as well as
unavoidable impurities. The high wear resistance is achieved by the
very high nickel and silicon contents, the effect of which is that
the matrix contains a high volume content of nickel silicides. The
lattice comprises no y phase and consists primarily of .beta.
phases. Lead in small amounts is considered useful with a view to
good processability.
[0011] Furthermore, German patent DE 28 30 459 C3 and its
counterpart U.S. Pat. No. 4,191,564 relate to a copper-nickel alloy
with high wear resistance, which consists of 45 to 75 wt. % copper,
2 to 7 wt. % aluminum, 0.1 to 2 wt. % iron, 1 to 5 wt. % nickel,
0.5 to 2 wt. % silicon, 0.1 to 2 wt. % cobalt and the remainder
zinc. For the high wear resistance, this alloy furthermore contains
an intermetallic compound of the nickel-silicon type, into which
aluminum and cobalt are also bound. It does not contain lead.
[0012] Finally, in German patent DE 38 09 994 C3 and its
counterpart U.S. Pat. No. 4,995,924, a copper-zinc alloy is formed
for a synchronizer ring from 20 to 40 wt. % zinc, 2 to 8 wt. %
aluminum, from at least two further components which form
intermetallic compounds, at least one of the components being
titanium, and for the remaining part from copper and random
impurities. The high wear resistance is achieved by the
intermetallic compounds. Lead is unnecessary.
[0013] A feature common to the low-lead and lead-free copper-zinc
alloys which have a high wear strength is that they have a high
content of intermetallic phases. These intermetallic phases lead to
a certain brittleness of the alloy, so that it becomes easier to
machine process. The swarf breaks readily and can be transported
away. For this reason, the proportion of lead can be reduced or
lead can be omitted. If a high wear resistance is not required, as
in U.S. Pat. No. 6,413,330 and European patent EP 1 045 041 B1,
then the lead content can be reduced by stabilizing a y phase in
the alloy through an interaction of silicon, aluminum and
phosphorus. This alloy contains phosphorus in order to ensure a
dezincing resistance of the alloy for the desired application in
the sanitary industry.
SUMMARY OF THE INVENTION
[0014] It is accordingly an object of the invention to provide a
copper-zinc alloy, which overcomes the above-mentioned
disadvantages of the heretofore-known devices and methods of this
general type and which provides a maximally wear-resistant
copper-zinc alloy which is largely lead-free and which, in
particular, is suitable for use in a synchronizer ring.
[0015] With the foregoing and other objects in view there is
provided, in accordance with the invention, a copper-zinc alloy
which comprises 55 to 75 wt. % copper, 0.1 to 8 wt. % aluminum, 0.3
to 3.5 wt. % iron, 0.5 to 8 wt. % manganese, 0 to less than 5 wt. %
nickel, 0 to less than 0.1 wt. % lead, 0 to 3 wt. % tin, 0.3 to 5
wt. % silicon, 0 to less than 0.1 wt. % cobalt, 0 to less than 0.05
wt. % titanium, 0 to less than 0.02 wt. % phosphorus, unavoidable
impurities and the remainder zinc.
[0016] The invention is based on the idea of deliberately lowering
the lead content below 0.1 wt. % without providing compensation in
respect of the desired mechanical processability by intermetallic
phases or stabilisation of a y phase. A sufficient wear resistance
is ensured by the necessary alloy components aluminum, manganese,
iron and silicon. Manganese, iron and silicon in the specified
quantitative ranges lead to a sufficient basic proportion of
intermetallic phases in the copper-zinc alloy. In particular,
aluminum hardens the mixed crystal. Manganese makes a positive
contribution to the wear resistance. An improvement can be achieved
through the optionally mentioned further alloy components nickel
and tin. It may contain cobalt and titanium up to below the
specified limits. Alloying it with them beyond this, however, is
unnecessary for the desired mechanical processability and for
achieving the desired wear resistance. Phosphorus as an alloy
component is unnecessary for improving the dezincing
resistance.
[0017] Lowering the lead content below 0.1 wt. % without increasing
the proportion of intermetallic phases is surprisingly possible,
contrary to the previous opinion of the technical world, since it
has been found after extensive studies that it is possible to
machine the claimed copper-zinc alloy, particularly for producing a
synchronizer ring, even without adding lead.
[0018] The wear resistance and the abrasion strength of the
copper-zinc alloy can be improved when the copper-zinc alloy
advantageously comprises aluminum in a proportion of from 0.5 to
2.5 wt. %, iron in a proportion of from 0.3 to 1 wt. %, manganese
in a proportion of from 0.5 to 5 wt. %, nickel in a proportion of
from 0.5 to less than 5 wt. %, tin in a proportion of from 0 to 1.5
wt. % and silicon in a proportion of from 0.3 to 2 wt. %.
[0019] In an alternative advantageous embodiment of the invention,
the copper-zinc alloy comprises a higher proportion of aluminum and
is distinguished in that it comprises aluminum in a proportion of
from 3 to 8 wt. %, iron in a proportion of from 1 to 3 wt. %,
manganese in a proportion of from 5 to 8 wt. %, nickel in a
proportion of from 0 to less than 0.5 wt. %, tin in a proportion of
from 0 to less than 0.5 wt. % and silicon in a proportion of from 1
to 4 wt. %. Such a material has the mechanical properties necessary
for a synchronizer ring.
[0020] The copper-zinc alloy is suitable for producing a
synchronizer ring--also referred to as a synchronizing
ring--particularly by machining.
[0021] Other features which are considered as characteristic for
the invention are set forth in the appended claims.
[0022] Although the invention is described herein as embodied in
copper-zinc alloy and synchronizing ring produced therefrom, it is
nevertheless not intended to be limited to the details shown, since
various modifications and structural changes may be made therein
without departing from the spirit of the invention and within the
scope and range of equivalents of the claims.
[0023] The construction and method of operation of the invention,
however, together with additional objects and advantages thereof
will be best understood from the following description of specific
embodiments and examples.
BRIEF DESCRIPTION OF THE DRAWING
[0024] The sole figure of the drawing is a perspective view of a
synchronizer ring according to the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0025] Referring now to the figure of the drawing in detail there
is shown a synchronizer ring--also referred to as a synchronizing
ring--as can be produced in particular by machining from a
copper-zinc alloy. The synchronizer ring 1 has an inner surface 3,
which is intended for friction pairing with a conical friction
partner. Teeth 2, which engage with corresponding slots on a mating
slotted sleeve, are arranged on the outer circumference of the
synchronizer ring 1. In order to improve the oil run-off, the inner
surface 3 has oil channels 4 fitted in an axial direction, which
rapidly transport away the oil present in the case of friction
pairing.
EXAMPLES
[0026] Four alloys were studied in all, each pair of alloys
differing only in its lead content. Alloy 1A contains 57.9 wt. %
copper, 1.65 wt. % aluminum, 0.4 wt. % iron, 1.95 wt. % manganese,
0.55 wt. % lead, 0.6 wt. % silicon and the remainder zinc. Alloy 1
B differs from this alloy 1A in that lead is absent from it, i.e.
it contains lead only at an unavoidable impurity level of 0.02 wt.
%. Alloy 2.beta. contains 69.7 wt. % copper, 5.2 wt. % aluminum,
1.1 wt. % iron, 7.8 wt. % manganese, 0.8 wt. % lead, 1.8 wt. %
silicon and the remainder zinc as well as unavoidable impurities.
Alloy 2B differs from alloy 2A in that it contains lead only at an
unavoidable level of 0.05. Alloys A are comparative alloys
containing lead, which are suitable in respect of their wear
resistance and processability for synchronizer rings. The alloys B
are embodiments of the invention.
Example 1
[0027] For the said alloys, the wear strength in km/g and the
friction coefficient are determined in a Reichert friction-and-wear
balance with a sliding speed of 1.65 m/sec and a load of 52
N/mm.sup.2 over a total traveled distance of 2500 m. To this end a
brass pin made of the respective test alloy with a diameter of 2.7
mm is pressed with the specified load onto a revolving steel ring.
The wear strength and the friction coefficient are determined from
the weight loss of the brass pin after the specified running
distance. The result is summarized in the following table:
TABLE-US-00001 Wear strength Alloy, Number (km/g) Friction
coefficient 1A 201 0.12 1B 235 0.12 2A 1215 0.11 2B 1458 0.11
[0028] It can be seen that the wear strength and the friction
coefficient of the lead-free alloys B are not inferior relative to
the alloys A containing lead, but on the contrary have
increased.
Example 2
[0029] Cutting tests are carried out with the said alloys. To this
end a screw thread with a thread depth of 0.37 mm, a pitch of 0.65
mm and a flank angle of 60.degree. is cut into synchronizer rings
according to FIG. 1, which are made of the test alloys. The thread
groove is run through five times in all; i.e. there are five thread
chases. A hard metal material of quality K20 according to DIN 4990
is used as the thread cutting material. After a defined number of
thread grooves cut with the cutting tool, the tool wear is
measured. To this end the difference in the cross-sectional area of
the thread pitch before and after carrying out the test is
determined. The following result is obtained:
TABLE-US-00002 Number of thread Alloy, Number grooves cut Tool wear
in mm.sup.2 1A 6846 0.0226 1B 14670 0.0085 2A 10273 0.0015 2B 10273
0.0005
[0030] The test was stopped after 6848 thread grooves for alloy 1A,
since significant tool wear had already taken place here. It can be
established that the tool wear with the lead-free alloys B turns
out to be less than with the alloys A containing lead.
Example 3
[0031] The swarf removed in the cutting tests carried out according
to Example 2 was observed. It was established that although the
swarf of the lead-free alloys B was longer compared with the alloys
A containing lead, it did not form in such a way as to interlink
and tangle together. Contrary to expectation, the swarf can be
transported away without problems during machining.
[0032] The lead-free alloys are suitable particularly for producing
a synchronizer ring. The need for the addition of lead to improve
the mechanical processability is therefore obviated.
* * * * *