Apparatus for the inductive hardening by quenching of bearing surfaces of a crankshaft

An apparatus for inductively hardening by quenching of the running surface of bearings of a crankshaft in which the crankshafts are transported by a lifter-conveyor system to a clamp which grips the crankshaft and is pivoted about a lever arm pivotably mounted on the machine frame to a heating position below a plurality of inductors. The inductors ride on the crankshaft as it rotates to inductively heat the running surfaces. The inductors are each mounted on a linkage which also mounts a quenching shower and the linkage in turn is swingably mounted on a further lever arm which is pivotably connected to the machine frame. As the crankshaft rotates, the inductor lifts and the further lever arm lifts off a stop. The apparatus preferably includes a second clamp and set of inductors to which the crankshaft is subsequently conveyed for further treatment after hardening.

The invention relates to an apparatus for the inductive hardening by 
quenching of the running surface of a lifting bearing of a crankshaft. 
Machines are known with a clamping arrangement disposed in a machine frame 
for the rotatable mounting of the crankshaft around a horizontal 
rotational axis, and, disposed above the clamping arrangement, a movable 
mounted inductor feedable with an electric AC current and being capable of 
being arranged in a heating position on the running surface of the bearing 
to inductively heat the running surface of the bearing. Such machines 
include a shower arrangement connected with the bearing arrangement of the 
inductor for the feeding in of a fluid coolant for quenching the heated 
running surface of the bearing in which case the inductor arrangement is 
swingably mounted to be movable in two directions transversely to the axis 
of rotation of the clamping arrangement in such a way, that upon rotation 
of the eccentric lifting bearing of the crankshaft, the inductor rotates 
on the lifting bearing surface. A conveying arrangement is provided below 
the clamping arrangement for the horizontally lying feeding-in of the 
crankshaft into a clamping position in which the shaft may be clamped into 
the clamping-in arrangement. 
In known machines of this type, the crankshaft is moved into its starting 
position for hardening by a lifter-conveyor, is received in this starting 
position between dead centers of a pair of spindles and is lifted and 
clamped down at the same time. The inductor arrangement disposed above 
this clamping arrangement is then lowered to the surface of the lifting 
surface of the crankshaft. In case of a rotating crankshaft, the inductor 
is lifted and swung, and the lifting bearing is heated inductively. 
Finally, after the heating, the bearing is quenched by spraying on a 
quenching liquid to form martensite. Such arrangements have the 
disadvantage that the shaft must be lifted by a special development of the 
clamping arrangement, from the lifter-conveyor and the inductor 
arrangement in order for it to be lowered, must be movably mounted on a 
separate carriage in a vertically running direction. As a result, a 
relatively precise positioning of the crankshaft in the clamping-in 
position and an extremely long lifting path of the inductor arrangement 
become necessary, as a result of which not only the constructional height 
of the machine must be enlarged, but also the flexible electric feed lines 
for the medium frequency electric AC current to the inductor or pertinent 
construction units must be disadvantageously lengthened. 
The present invention deals with an improvement of machines of this type so 
that the movability of the inductor arrangement transverse to the 
rotational axis of the crankshaft is limited to a short distance, 
determined by the reach or the lift of the lifting bearing in the 
crankshaft, in addition to its possible thermal changes of position. The 
flexible electric feed lines to the inductor may therefore correspondingly 
be shortened and the degree of effectiveness of the arrangements improved. 
At the same time, the costs of the bearings for the inductors can be 
reduced and the function of the machine simplified. 
According to this invention, the clamping arrangement is disposed on the 
machine frame on a lever arm swingable around a rotational axis between a 
clamping in position disposed in the path of transportation of the 
transportation arrangement and a heating position below the inductor. This 
development has the advantage that the crankshaft which is to be processed 
by means of the machine may be moved by means of the transportation 
arrangement into a locally fixed clamping down position, may be clamped 
down there by means of a clamping arrangement, may be brought by rotation 
about a horizontal axis into a position predetermined by the position of 
the inductor and may be transferred into a working position by lifting of 
the clamping arrangement in which working position the inductor 
arrangement rests on the bearing surface of the lifting bearing in a low 
lying position of said lifting bearing. Upon rotation of the crankshaft 
around its longitudinal axis, the inductor arrangement need only to be 
lifted by a distance which corresponds to the distance required to clear 
the lifting bearing of the crankshaft. 
Thus, a conventional transportation arrangement can be used. Furthermore, 
the arrangement may be made in such a way that the machine frame for the 
mounting of two arrangements disposed on the path of the transportation 
arrangement, has arrangements for the inductive heating and subsequent 
quenching of running surfaces of the bearing of the crankshaft, of which 
one arrangement serves for the hardening of the lifting bearings and the 
other arrangement for the hardening of the main bearings of the shaft. In 
the hardening station for the main bearings of the shaft, the movability 
of the inductor in regard to height now needs to be still adapted to the 
maximum heat delay of the crankshaft, as a result of which the electric 
flexible feed lines may be kept particularly short.

In FIG. 1 base frame 1 of the machine is set on a foundation and mounts a 
vertically extending portal-like support 2 with a covering 3 disposed 
above it. The base frame 1 mounts a transportation means in the form of a 
lifter-conveyor consisting of a locally fixed solid beam system 4 with an 
assigned lifter system 5. The solid beam system 4 (cf. also FIG. 2) 
consists of two parallelly disposed beams 4 and 4A which are provided with 
pairs of bearings 6 longitudinally separated from one another. A pair of 
bearings 6A is disposed at the inlet of the lifter-conveyor to receive a 
horizontally disposed crankshaft which is inserted in the corresponding 
bearing pair of the two solid beams 4 and 4A. For placement on input 
bearings 6A, the crankshaft is lifted step by step by corresponding 
transportation movements of the lifter system 5, which consists of two 
parallelly disposed beams, and is then moved onto the next following 
bearing 6, in the direction of arrow 7. For this purpose, the lifter 
system 5 is moved via a corresponding mechanical gearing by means of 
hydraulic piston motors 8 and 9 in a known manner perpendicularly in 
relation to the plane of the solid beam system 4, 4A and parallel thereto 
on a closed transportation path of movement. After several transportation 
steps, the crankshaft K reaches the clamp-in position 6B disposed on the 
fixed beam system, from the starting position at bearings 6A. The numeral 
10 designates a clamping arrangement swivelably mounted around rotational 
axis 12 on a lever arm 11, which arrangement is mounted rotatably around 
the bearings 13 and 14 in the frame 2 for movement through swiveling angle 
.alpha.. 
The clamping arrangement 10 consists of a chuck 20, the clamping jaws of 
which may be opened and closed hydraulically by means of a hydraulic 
piston motor 21. Opposite chuck 20, a casing 22 may be shifted by means of 
a hydraulic piston motor 23 toward chuck 20. The clamping arrangement 10 
itself may be swivelled by means of the hydraulic piston motor 24 around 
rotational axis 12 and may be turned into a clamping in position in which 
the chuck 20 and the casing 22 grip on both sides of the shaft ends 
crankshaft K which is located in position 6B. By operating piston motor 
23, shaft K may be gripped by chuck 20 and after that it may be clamped 
down by operation of the piston motor 21 in the chuck arrangement 20. 
Then, the unilaterally clamped in crankshaft is relieved of the pressure 
of the clamping casing 22 by operation of the motor 23, so that the shaft 
is clamped down unilaterally. In this operating phase, the crankshaft K is 
turned around its rotational axis and is aligned with its lifting bearing 
that is to be hardened so that the bearing will assume a suitable starting 
position for treatment by the inductor. 
By operation of the motor 24 finally, the clamping arrangement 10 is lifted 
out of its clamping-in position into its operating position for which 
purpose the clamping arrangement 10 is turned by the angle .alpha. around 
its rotational axis 12. 
The numeral 30 designates a linkage swingably mounted around rotational 
axis 31 which runs perpendicularly in relation to the plane of the drawing 
of FIG. 1, which linkage is articulated to a one-armed lever 32. The lever 
32 is pivotably attached to frame 2 for rotation about axis 33 which runs 
perpendicularly to the plane of the drawing. The lever arm 32 rests on a 
stop 34 which can be adjusted in height. 
Linkage 30 mounts a medium frequency transformer 35 and an inductor 36 
which has the shape of a half shell inductor. The primary winding of the 
transformer 35 is connected via a flexible electric feed line 37, assigned 
relays 38 and capacitors 39 with a source of medium frequency current (not 
shown). 
In the operating position of the clamping arrangement 10, an electric motor 
25 turns (rotates) chuck 20 around the longitudinal axis of crankshaft K, 
as a result of which the latter is rotated around its longitudinal axis 
and the inductor heats the lifting bearing inductively. 
Referring to FIG. 2, three additional transformers and inductors are 
disposed beside the transformer 35 and the inductor 36 connected firmly 
with the transformer, which likewise form separate construction units for 
the heating of additional lifting bearings of the crankshaft. Each of the 
inductor construction units is rotatably mounted around a further lever 
arm 32 so that it may be lifted from a pertinent stop 34, whereby the 
weight of the pertinent linkage 30, as a result of counter weights, etc., 
is relieved of its weight via a rope pulley 40, which engages by way of a 
roller 41 with arm 32. 
The inductors 36 are additionally provided with shower arrangements in a 
manner known per se, which may be fed a quenching liquid by flexible lines 
50. Flexible cool water pipes 51 and 52 feed the windings of the 
transformers and the windings of the inductor arrangements with cooling 
water, so that excess heat is eliminated from these construction parts. 
The machine described hereby operates as follows. A crankshaft inserted, 
e.g., manually into the input bearing arrangement 6A is transported into 
the clamping down position 6B by means of the lifter-conveyer. After that, 
the clamping down arrangement 10 is lowered to the clamping down position 
and the workpiece K in the clamped down position is clamped down by means 
of the clamping arrangement. After that the crankshaft is turned into its 
first operating position and the clamping down arrangement 10 is 
transported around the rotational axis 12 into the pertinent operating 
position in which the inductors 36 rest on the pertinent lifting bearings 
of the crankshaft. After that, the motor 25 is again operated which turns 
the crankshaft around its longitudinal axis, whereby the inductors 36 
participate in the pertinent rotational movement on the surfaces of the 
lifting bearings, while the linkage 30 swings around the rotational axis 
31. Simultaneously, the linkage 30 is in a position to participate in the 
pertinent lifting movement by lifting the lever arm 32 off the stop 34 as 
it rides on the crankshaft. This lifting movement takes place free of the 
weight-forces originating from the weight of the transformers and the 
inductors or of the linkage 30, which forces are absorbed via the relief 
of the pulley 40 and roller 41. 
During the rotation of the crankshaft around its longitudinal axis, the 
inductors are fed a medium frequency current which heats the running 
surfaces of the bearings of the crankshaft inductively. After sufficient 
heating, the running surfaces of the bearings are quenched by operation of 
the pertinent shower arrangements and the quenched crankshaft is again 
transferred into the clamping position 6B by lowering the clamping 
arrangement, and again to the transportation means by unclamping the 
workpiece, which transportation means transfers the workpiece into the 
second clamping position 6C to which analogously as described, a clamping, 
induction heating and quenching arrangement are assigned. The pertinent 
clamping arrangement 10A, in turn, is mounted swivelably in a rotational 
axis 12A and conveys the workpiece located in the clamping position 6C 
into an operating position in which pertinent inductors will heat the main 
bearing surface of the workpiece, and the assigned shower arrangements 
will subsequently quench the heated running surfaces of the bearing. After 
that, the workpiece is again moved back into the clamping position 6C and 
is conveyed by means of the transportation arrangement, disposed on the 
frame 1, and by means of an additional separate transportation arrangement 
(not shown) out of the area of the machine. 
The invention is not limited to the embodiment shown. Thus, for example, 
the induction hardening arrangements for the main and the lifting bearings 
of the camshaft may be interchanged in the path of transportation of the 
conveying arrangement. The control and adjusting arrangements for the 
rhythmical operation of the machine have not been shown in detail. Thus, 
for example, a control arrangement belongs to the clamping down 
arrangement 10 of the machine which operates it by terminal bearing 
switches and permits holding the crankshaft K in certain clamping 
positions by operation of the motor 25 which transports the workpiece into 
certain angular positions. Many other changes and modifications to the 
above described embodiment of the invention can, of course, be made 
without departing from the scope of the invention, that scope being 
limited only by the scope of the appended claims.