SYSTEME D'ENTRAINEMENT POUR LAMINOIR PAS DE PELERIN A FROID

DRIVE SYSTEM FOR A COLD PILGER ROLLING MILL

Abrégé anglais

ABSTRACT
The present invention relates to a drive system for a
cold pilger rolling mill, incorporating equalisation of masses
and moments, the driven crank being connected to the rolling frame
through a connecting rod. In order to arrive at a compact, cost-
effective and, as far as possible, lightly loaded structure for
the drive system, it is proposed that the rolling frame (WG)
be arranged directly above the crank gearing (RU) and the connect-
ing rod (KO) be supported directly on the crank journal (3), so
that the connecting rod effects moment equalisation with its total
mass, and the crank (KU) effects equalisation of mass with its
total mass.

Revendications

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A drive mechanism for a cold pilger rolling mill
comprising a roller stand that is connected to a driven crank in a
crank mechanism by a connecting rod that is carried by an
eccentric crank pin on said driven crank, characterized in that
the roller stand is located directly above the crank mechanism and
the connecting rod is mounted directly on said crank pin, the
total mass of the connecting rod providing torque balancing and
the total mass of said driven crank providing mass balancing.
2. A drive mechanism according to claim 1, characterised in
that the connecting rod is guided in restraint guides in the
region of its extreme positions of movement.
3. A drive mechanism according to claim 1, characterised in
that said driven crank comprises part of a planet gear, that a
pinion is located on the crank pin and connected securely thereto,
which pinion meshes with an internal-toothed ring gear surrounding
said crank in such a manner that the superposition of the
rotational motion of said pinion and said crank imparts to said
connecting rod an opposing rotational motion.

Description

`` ,.^` 132713~
... .
The present lnventlon relates to a drlve system for a
cold pilger rolling mlll, incorporating the means to balance
ma~es and torques or moments.
DE-AS 27 40 279 descrlbes a cold pilger rolllng mill of
this kind wherein, the crank mechanism i8 arranged to one side,
relative to the rolling mlll. The crank is connected through a
crankshaft offset to a balancing mas~ that i8 arranged above the
crank mechanisD, this balanciny mass balancing out the operating
torques or moment~. This phase shifted through 90 degrees
-., . .~
relatlve to the crank, and the reciprocating movement is made
po~sible by parallel guides. The rolling mill itself 18 coupled
through a long connecting rod that 18 supported on one side, on
the crank~haft offset.
The present invention aims to develop a compact, cost-
effective design for the drive, this being sub~ected to reduced
load~.
The present invention i8 a drive mechanism for a cold
pilger rolling ~ill compriaing a roller ~tand that 1B connected to
a driven crank in a crank mechanlsm by a connecting rod that i~
carried by an eccentric crank pin on said driven crank,
characterlzed in tha~ the roller stand is located directly above
the crank mechani~m and the connectlng rod 18 mounted directly on -
6aid crank pin, the total ma~s of the connecting rod providing
~orque balancing and the total mass o~ said drlven crank providing
mass balanclng.
.i
The construction, which in total is vertical, makes it
possible for the rolling frame to act on one ~lde and thu~ be
3a;. . . -. .:
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1327134
guided on the whole of the gear unit. This makes it possible to
dispense with a connector rod that connects the rolling frame with
the gear unit.
The connecting rod engages directly on the slide
immediately below the rolling frame.
The mass that is required for balancing the moments is
formed by the connecting rod itself. The centre of mass of the
connecting rod is located above the point D of the positive guide.
The total mass of the connecting rod is reduced onto the point D,
which means that the dimensions of the connecting rod can be kept
small (flat construction). ~;
The connecting rod rotates by P and contributes - -
to improved uniformity of the total system by virtue of its moment
of mass inertia QKO- Because of the design and arrangement of
the connecting rod the planes of the centre of mass of the moment
equalisation, of the mass equalisation, and of the rolling frame
are brought a6 close together as is possible. As a result of this
it has been made possible to arrive at a compact structure and
relatively light loading within the gear unit.
The slide guide and the positive guide lie in approxi-
mately the same plane. This has been made po~sible by an inter-
ruption of the positive guide. The positive guide i~ required
only in the end positions in order to maintain the direction of
ro'ation of the connecting rod and the crank. An optimal setting
for the geometrical arrangement and the loading of the bearings
and the trunnions has been arrived at by supporting the connecting
rod on the crank.

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The embodiment shown in Figure 3 represents a modified
embodiment incorporating an epicyclic gear train and crank (PKG).
The construction of this PKG is almost identical to the first
embodiment of a double slide gear (DG) described heretofore, but
differs in that there is no positive guide. This has been re-
placed by an epicyclic gear train that consists of a sun gear and
an internally toothed ring. The sun gear is fixed on the crank
journal and rotates on the ring gear because of the rotational
motion of the crank. The superpositioning of the rotational -
motion of the sun gear and the crank results in a precisely
opposite direction of rotation of the connecting rod. The -~-
.: ..
opposing rotational movement with the angular velocity ~=w
and maintenance of the existing geometrical conditions results in
a di6placement of the point B (rolling frame).
The disadvantages of the conventional double slider ~ -~
gearing, and the advantages of the double slider gearing and of
the epicyclic gear train according to the present invention are
... . .
compared in point form below.
.:" ,' .:"
.; .
Conventional Double Slide Double Slide Gearing or Epi-
Gearing cyclic Gearing-crank according --
to the present invention
- Horizontal construction - The vertical and assym-
requires a thrust- or metrical construction means
: ,-, . ..
connector rod. that no thrust rods are
required.
~ .
. . .
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13271~
- The great di6tance between - The mass required for
the planes of the centres of balancing moments is provided
mass lead to very high loading by the mass of the connecting
of the bearings and journals. rod.
- Costly bearings for the - The elevated mass inertia
crank, connecting rod, equal- moment of the connecting rod --
isation of moments, and the contributes to improved
rolling frame. uniformity of the overall
system. ~ -
- The centre of mass of the
connecting rod extends beyond
the point D. Because of the
mass that i5 reduced onto the
point D, the total mass and the
in~talled height of the con-
necting rod are reduced.
:
- The planes of the centres of
gravity of the mass and moment ;~
equalisation and of the rolling
frame are æeparated by a rela-
tively short distance. This
reduces the loading on the
bearings and the journals.
' ' -
. :- ~''
- 4 -
'-

1 3 2 7 1 3 ~
- Interruption of the po~itive -~
guidance eliminates the yreat
demand for precision in the two
guides relative to each other.
. :.'
- There iR no need for storing
or releasing potential energy :
. :. ,
since gravity acts in the .
direction of the main axis of
rotation.
.. . .
- In the case of the epicyclic. -~
gear train-crank, the po~itive ...
guidance i8 completely elim- .
.. . ...
inated.
~ " ',: ~, . ;
, .
- The guidance of the connecting
rod within the positive guide is . ~.
effected by means of a cam
follower.
- The number of bearings is ;~
considerably reduced (from 12
to 5).
.' .''-., ,'.
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The present invention is described in greater detail
below on the basis of the drawings of two embodiments appended
hereto, wherein:-
Figures la, lb show schematically a cross-section and a
plan view respectively of the first embodiment of the drive
according to the present invention (double slide gearing);
Figure 2 shows a cross-section through an embodiment of
this first drive;
Figures 3a, 3b show the movement of the connecting rod
and crank in two positions;
Figures 4a, 4b show schematically a cross-section and a
plan view respectively of a second embodiment of the drive
according to the present invention (epicyclic-crank drive);
Figure 5 i8 a cross-section through an embodiment of
this second drive.
The first embodiment, with the so-called double slide
drive, will be explained first.
The rolling frame (WG) can move within a slide guide
(Sch). The rolling frame is connected to the connecting rod (K0)
through a journal; this connecting rod is arranged beneath the ~ -
rolling frame and runs about a vertical axis.
As can be seen from Figures la, lb, and 2~ the con-
necting rod (K0) has a cam follower (1), by means of which the
connecting rod (K0) is guided in the positive guides (2). How-
ever, these positive guides (2) are only provided in the area of
the end positions of the cam follower (1) or the connecting rod
(R0), respectively. The connecting rod (K0) is connected with the
crank (KU) through the crank journal (3). Figure lb shows the
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` 1327131 :
. -
movements of the crank (KU), connecting rod (KO) and slide (4) ~-
(i.e., of the rolling frame). In these Figures la, lb and the
following Figures 3a to 4b, x and y are the slide coordinates,
SWG, SKo, and SAG are the centres of mass of the rolling frame WG,
the connecting rod KO, and the equalizing mass MA, P and P ~-
are the directions of rotation of WG, K0, and KU; R stands for the `
radii of the articulation between the connections WG, KO, and KU, -~ -
Sch is the guide for the rolling frame WG, and Z is the vertical
axis in which the rolling frame, the connecting rod, and the crank
lie. ^~
Figures 3a and 3b serve to better clarify the sequence
of movement; these drawings show the connecting rod (KO) and the
crank (KU) in different positions relative to each other. As - -
Figure 2 shows, the crank (KU~ is connected to the drive 8 (not
shown herein) through a suitable gear train arrangement (5 - 7).
The second embodiment, shown in Figures 4a, 4b, and 5 -~
differs from the first embodiment in that an epicyclic gear and
crank arrangement i8 used in place of the positive guide. -~
A sun pinion (9) is fixed on the crank journal (3) of
the crank (KU); this sun pinion runs around an internally toothed
ring (10) that surrounds the crank (KU~. As is shown in
~igure 4b, this arrangement means that because of the super-
imposition o~ the movements of the crank (KU) and the sun pinion
(~1 the connecting rod (KO) will move in the opposite direction.
The displacement of the point B on the rolling frame
results from the kinematic consideration for equally large,
opposing rotational motions, with due consideration of the
geometry set out in Figure 4b.
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Dessin représentatif