Electric heating – Inductive heating – Specific heating application
Patent
2000-05-26
2000-12-12
Leung, Philip H.
Electric heating
Inductive heating
Specific heating application
219672, 219673, 148572, 266129, H05B 610, H05B 644
Patent
active
061602485
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a device for simultaneous peripheral electro-inductive hardening of bearing surfaces and transition radii on crankshafts, comprising lifting pins arranged directly adjacent to each other and one behind the other with different angular positions in the plane perpendicular to the axis of rotation of said crankshafts.
Such devices for electro-inductive hardening of so-called "split-pin crankshafts" which have lifting pins arranged directly adjacent to each other and offset are sufficiently known from practice in the automotive industry, it being endeavored with a number of known designs to harden the bearing surfaces of the directly adjacently arranged lifting pins of a crankshaft simultaneously with little mechanical expenditure and to obtain a desired grain structure.
For example, DE 36 13 309 discloses a method and a device for the inductive hardening of bearing surfaces and transition radii on "split-pin crankshafts", the bearing surfaces and transition radii of the lifting pins arranged directly one behind the other being simultaneously peripherally hardened by inductors which are arranged oppositely offset perpendicularly with respect to the axis of rotation of the crankshaft.
This solution offers the advantage that there is considerable space available for the configuration of the individual inductor and that mutual inductive influencing of the inductors is avoided. Furthermore, the lateral feeding of the inductors respectively reaching around the lifting pins in a half-shell shape permits maximum wrapping enclosure without the inductors touching during rotation of the crankshaft. With regard to their design, however, the opposite arrangement of the inductors requires relatively great expenditure.
DE 40 01 887 discloses an improved solution with a method and a device for hardening crankshafts, comprising pins separated from one another by webs, the inductors being brought into contact with the pins from the same side, said pins being narrower than the width of the hardening zone and the inductors being designed in a known way such that the surface region to be heated to hardening temperature is increased in comparison with the width of the inductor and the distance between the inductors is chosen such that the heating-up regions of neighboring inductors merge with one another.
With the feeding of the inductors from the same direction, preferably from above, this solution requires significantly lower mechanical expenditure for hardening. However, to avoid axial contact of the inductors in their region of radial overlap, the angle of wrap of the inductors must be chosen to be shorter than in the case of an opposite feeding of the inductors, which leads to disadvantages with regard to the efficiency of the hardening method and the depth of hardening to be achieved by it, in particular uniform hardening of radii.
This restriction also exists with a design of the inductors known from practice, with portions of different widths, an inductor portion that serves predominantly for radial hardening covering over half the bearing width and a second inductor portion being formed such that it is correspondingly narrower, to avoid a collision with the identically designed other inductor. Since the inductor portions in this set-back region are not effective on the inner radius, there remains, seen from the center of the lifting bearing pin, only a maximum effective angle of wrap of approximately 50.degree., with which prescribed hardening tolerances can often be maintained only with difficulty.
The present invention is therefore based on the object of providing a device of the type stated at the beginning which can be realized in terms of structural design in a simple and low-cost way and which permits increased efficiency while ensuring optimum hardening of bearing surfaces and radii.
This object is achieved according to the present invention.
With the device according to the invention, both the advantages of wrapping a long way around the lifting pins with regard to the hardening depth and
REFERENCES:
patent: 4300031 (1981-11-01), Reboux et al.
patent: 5157231 (1992-10-01), Baeurele
patent: 5451749 (1995-09-01), Griebel et al.
patent: 5495094 (1996-02-01), Rowan et al.
Ottenwaelder Adalbert
Traub Harald
Leung Philip H.
Maschinenfabrik Alfing Kessler GmbH
LandOfFree
Device for electro-inductive hardening of bearing surfaces and t does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Device for electro-inductive hardening of bearing surfaces and t, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Device for electro-inductive hardening of bearing surfaces and t will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-220214