U.S. patent application number 11/717929 was filed with the patent office on 2007-10-11 for method for producing a compression connection.
Invention is credited to Arnd Kobus, Harald Rudiger Muller, Mario Prokop, Alexander Puck.
Application Number | 20070234988 11/717929 |
Document ID | / |
Family ID | 38438186 |
Filed Date | 2007-10-11 |
United States Patent
Application |
20070234988 |
Kind Code |
A1 |
Kobus; Arnd ; et
al. |
October 11, 2007 |
Method for producing a compression connection
Abstract
A method for producing a compression connection for a driving
part (1), in particular for an essentially ring-shaped driving part
(1) on a shaft (3), in particular in the case of a built-up
camshaft with which the driving part (1) has an opening that
essentially corresponds to the outside diameter of the shaft (3),
the driving part (1) sits on the shaft with coverage in the
finished compression connection, an adhesive layer is applied
between the circumferential surfaces of the driving part (1) and
the shaft (3), is to be improved. To this end, such a method is
characterized by the following features: the driving part (1) is
heated until reaching the joining temperature and is thereby
widened, the driving part (1) is pushed on to the shaft essentially
without any forces.
Inventors: |
Kobus; Arnd; (Korb, DE)
; Muller; Harald Rudiger; (Ostfildern, DE) ;
Prokop; Mario; (Neckarsulm, DE) ; Puck;
Alexander; (Esslingen, DE) |
Correspondence
Address: |
WILLIAM COLLARD;COLLARD & ROE, P.C.
1077 NORTHERN BOULEVARD
ROSLYN
NY
11576
US
|
Family ID: |
38438186 |
Appl. No.: |
11/717929 |
Filed: |
March 14, 2007 |
Current U.S.
Class: |
123/90.44 ;
123/90.17 |
Current CPC
Class: |
F01L 1/047 20130101;
F01L 2303/00 20200501; F16H 53/025 20130101; F16D 1/068 20130101;
B21D 53/845 20130101; B23P 2700/02 20130101; B21D 39/06 20130101;
B23P 11/025 20130101 |
Class at
Publication: |
123/90.44 ;
123/90.17 |
International
Class: |
F01L 1/34 20060101
F01L001/34 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 17, 2006 |
DE |
10 2006 012 358.1 |
Claims
1. A method for producing a compression connection for a driving
part (1), in particular for an essentially ring-shaped driving part
(1) on a shaft (3), in particular in the case of a built-on
camshaft, wherein the driving part (1) has an opening corresponding
essentially to the outside diameter of the shaft (3), the driving
part (1) sits on the shaft with coverage in the finished
compression connection, an adhesive layer is provided between the
circumferential surfaces of the driving part (1) and the shaft (3),
wherein the driving part (1) is heated until reaching the joining
temperature and is thereby widened, and the driving part (1) is
pushed onto the shaft in an essentially force-free operation.
2. The method according to claim 1, wherein the shaft (3) is joined
without after-working.
Description
[0001] The present invention relates to a method for producing a
compression connection for a driving part (e.g., cams, plugs, chain
wheels, phase adjuster, bearings, . . . ), in particular for an
essentially ring-shaped driving part on a shaft, in particular with
a built-up camshaft according to the preamble of Claim 1.
[0002] For many years, casting was the dominant production
technology for camshafts for passage vehicle engines. For many
years, however, there have increasingly been camshafts of the
built-up type of technology, whereby both technologies have their
specific properties and advantages as well as preferred areas of
use. For camshafts produced by the casting method, grey cast iron,
for example, is considered as the starting material, but chilled
cast iron is by far the most popular material for passenger vehicle
engines. For the designs of built-up camshafts available on the
market, there are various manufacturing technologies (MTZ volume
57, no. 5, May 1, 1996, pages 284-291). These built-up camshafts
consist essentially of a pipe (solid or hollow rod) on which the
driving parts are mounted by different methods. Among others,
joining methods are described in which conversion layers are
applied between the driving part and the shaft, and the joining can
be performed by longitudinal or transverse compression connections,
whereby the transverse compression connection is found to be a
disadvantage with respect to the complexity of innovative equipment
and the manufacturing tolerances that are difficult to
maintain.
[0003] German Patent DE 197 03 260 describes a built-up crankshaft
in which the cams and optionally also other add-on parts are
connected to a shaft coated with a conversion layer via a
longitudinal compression connection. This conversion layer may be
designed as an adhesive layer. In this process, the cam is joined
to a shaft cold and with a large coverage and thereby joined with
high axial and radial forces. The disadvantage of this method is
that due to the great coverage, great plastic deformations and
stresses and therefore cracks are introduced into the system, which
can no longer withstand the stresses in the valve drive. When the
conversion layer is embodied as an adhesive layer, there is the
additional disadvantage that the adhesive is displaced by the cam,
which is joined with a great coverage and therefore the effect of
the adhesive is lost entirely or at least has an extremely minor
effect. Due to the minor adhesive effect to this extent, the high
transferable torques required of future valve drives cannot be
achieved adequately. Another disadvantage of this longitudinal
compression method that should be mentioned here is that the shaft
must be remachined at the bearing points in a complex operation
after the joining process.
[0004] The present invention relates to the problem of providing an
improved embodiment of a method for producing a compression
connection for a driving part on a shaft, in particular in a
built-up camshaft.
[0005] This problem is solved in a generic method according to this
invention by the characterizing features of Claim 1.
[0006] This embodiment is characterized in that the driving part to
be joined to the shaft by an addition of compression seating and
adhesive seating is heated before being joined to the shaft and is
therefore expanded and is thus characterized on the whole as a
method involving no force, i.e., a joining method without coverage
and thus avoiding plastic deformations and stresses and therefore
cracks. Due to the joining method without force in which the
driving part is pushed onto the shaft with practically no friction,
the adhesive applied to the circumferential surfaces of the cam
and/or the shaft is preserved without scraping any off, so that an
optimal adhesive connection can be achieved. On the whole, this
method yields an especially stable connection with which the cost
and weight can be minimized while maintaining the same torques and
therefore the energy expended at the required highest torques of a
valve drive is lower on the whole, so this yields a connection that
is especially secure under stress. Due to the application of
adhesive, the hydrostatic pressure within the connection is
increased on the one hand while on the other hand the connecting
surface is increased due to the fact that the peaks in the surface
roughness is filled out within the connection.
[0007] This yields on the whole an especially high strength of the
connection, in particular a high shearing strength and therefore
very high transferable torques. Measurements have shown that
connections created by combining compression seating and adhesive
seating can withstand a torque at least one-third higher.
[0008] Therefore, materials having low specifications, i.e.,
materials with a relatively low strength, can be used for the shaft
while retaining the strength of the connection, or a low total use
of material is possible with the same material; this has a positive
effect on unit costs on the whole as well as the total weight of
the shaft. Another great advantage in terms of unit costs is the
fact that the energy required for the joining operation is kept low
on the whole because small joining lengths and lower joining
temperatures are possible, while at the same time achieving a
connection having a high stability. In addition, this method does
not require complex reworking of the shaft after the joining
operation, so this also has a positive effect on unit costs and the
total energy.
[0009] The driving agent is expediently heated by induction, hot
air or radiation. Modern induction heating in particular can
introduce energy into the driving part that is to be heated in a
targeted manner, so that it can be heated to conform to demands.
Induction heating generates an alternating magnetic field, which in
turn induces an alternating current in the electrically conducting
driving part. Because of the electric resistance of the driving
part, this current induced in the driving part causes heating of
same at the sites of where currents. With such induction heating,
it is thus possible to introduce heat specifically at certain
predefined locations through the shape of the inductor and/or by
regulating the frequency used, so that heat is generated
immediately and directly in the driving part itself, i.e., in its
interior, and need not be conducted by thermal conduction, as is
the case with a traditional oven which heats from the outside to
the inside.
[0010] All the driving parts to be mounted on the shaft can be
completely machined in advance so that no remachining of the
driving parts and shaft is necessary after they are mounted on the
shaft.
[0011] It is self-evident that the features mentioned above and
those yet to be explained below may be used not only in the
particular combination given but also in other combinations or
alone without going beyond the scope of the present invention.
[0012] Preferred exemplary embodiments of the invention are shown
in the drawings and explained in greater detail in the following
description.
[0013] The figures show schematically:
[0014] FIG. 1 a schematic diagram of a driving part,
[0015] FIG. 2 multiple driving parts mounted on a shaft by the
method according to the invention.
[0016] FIG. 1 shows a driving part 1, in particular a cam, having
an essentially ring-shaped design equipped with a bulge 2. In
addition, the driving part 1 has an opening 4 whose diameter
corresponds essentially to the outside diameter of the shaft 3
shown in FIG. 2. To allow the driving part 1 to be arranged on the
shaft 3 in a fixed manner, it is heated to create a compression
connection by the inventive method until reaching a joining
temperature, so that the diameter d of the opening 4 is increased.
The widening of the diameter d of the opening 4 may be only large
enough to allow the driving part 1 in the heated state to be pushed
onto the shaft 3 directly without exerting any axial or radial
forces and it solidifies on reaching a predetermined position and
then is joined fixedly to the shaft 3. The application of the
driving part 1 is thus limited according to this invention to the
extent that the adhesive applied to the connection of the driving
part 1 and/or the shaft 3 is not removed at all or not to any
considerable extent in the joining operation.
* * * * *