Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
  • F16C3/00—Shafts; Axles; Cranks; Eccentrics
  • F16C3/04—Crankshafts, eccentric-shafts; Cranks, eccentrics
  • F16C3/06—Crankshafts
  • F16C3/10—Crankshafts assembled of several parts, e.g. by welding by crimping

Definitions

• the present invention relates to a method for soldering a crankshaft from individual pieces, each comprising a cheek and part of an axle and a crank pin.
• crankshafts hollow and to build them from welded individual parts e.g. B. in DE-C-498 170.
• crankshaft To split the crankshaft into individual pieces so that each crank arm with at least one of the subsequent bearing or crank pin are made in one piece. Since the intention here is to provide the pins with special material properties, they are designed as pipe pieces to be welded or soldered between the cheek pieces; if this point of view is omitted, the pin parts can of course be connected directly to one another.
• soldering gap in the order of magnitude between 0.05 and 0.15 mm is then to be provided between the individual pieces, in which the liquefied solder, which was previously introduced into a deposit in the soldering gap or at one end thereof, is distributed as a result of the capillary action of the narrow gap.
• the amount of soldering material is of course measured so that it is sufficient to fill the entire gap. It expediently has an excess at least at one end of the soldering gap emerges and the optical assessment of the quality of the
• Solder connection can serve. It goes without saying that for this purpose the relevant end of the soldering gap must be visible, i.e. is expediently placed on the outside of the pieces to be joined together.
• the cited documents do not contain any explanations as to how the adjacent pieces of the crankshaft are brought into the correct position in relation to one another before welding or soldering and are held in this position during the connection process. However, it can be assumed that this is done by special devices, ie holding the individual pieces in the correct axial and angular position to one another. Such an outlay on equipment makes production more expensive and is also suitable for complicating the connection process itself. In order to be able to solder the crankshafts in a furnace, holding devices made of an expensive super alloy or ceramic, for example, would be required because of the high temperature.
• the object of the present invention is to provide a method for joining crankshafts from individual pieces, which is optimized for soldering technology and meets the following criteria:
• the first two requirements are met according to the invention by egg process, which is characterized in that the parts of an axle or crank pin belonging to different individual pieces are plugged together on one part of their U circumference with an interference fit and on another part of their circumference with the release of a soldering gap, and then be soldered together.
• the individual pieces pressed into one another in the correct orientation then no longer change their position, so that the crankshaft blank can be placed on a base or lying in a soldering furnace without the need for special holding devices.
• the depot for the solder material which is approximately in the form of a ring, is preferably arranged at the inner end of the strength-bearing soldering gap. With an optical inspection of the outside of the soldered crankshaft, the fact that the soldering overflows from the gap can be ascertained on the basis of the gap end located there and distant from the depot. If the solder depot is not arranged at the inner end of the entire gap (e.g. to ensure a clear fixation of the solder material ring), the part of the gap extending from here to the inside of the crankshaft is not considered to be load-bearing, since its correct filling also Solder material cannot be checked from the outside.
• pairs of individual pieces are used, in each of which one partner (because of the easier workability usually the inner one) is provided with at least a part of its contact surface with the other piece with an alternating surface structure having elevations and depressions, the elevations exceed the fit of the other piece, and the recesses fall below this fit.
• one partner because of the easier workability usually the inner one
• the elevations exceed the fit of the other piece, and the recesses fall below this fit.
• the one part is preferably provided with knurling on its surface which comes into contact with the other individual piece; this process is not very complex and is completely sufficient to produce the required surface structure with a roughness depth of a few tenths of a millimeter.
• connection point of the one piece can be provided with a straight or a spiral knurling according to alternative embodiments of the invention become; cross knurling is of course also possible.
• Joining can be finished as a partner for the axle or connecting rod bearings.
• the outer end of the soldering gap is preferably placed outside the machined surfaces of the pins , so that the said surfaces cannot reach from this flowing solder.
• the unprocessed transition area which is present between the crank webs and the subsequent pin parts anyway, usually a flute that is as flat as possible, can be used to absorb the excess solder by placing the outer end of the soldering gap in this flute.
• the movement is continued until a stop is reached which is formed by two surfaces which are inclined more or less strongly against the crankshaft axis.
• the gap of indefinite width remaining between them due to machining inaccuracies and surface roughness etc. is referred to as a "zero gap".
• This zero gap is to be arranged so that it does not come to lie between the soldering depot and the defined solder outlet and then acts as a soldering brake.
• parts of the surfaces of the connection points between the individual pieces that are not provided with elevations and depressions are arranged at the outer end of the soldering gap.
• a crankshaft joined by means of the method according to the invention is characterized in that the parts of an axle or crank pin belonging to different individual pieces are connected to one another by soldering extending over part of their circumference.
• Figure 1 shows part of a crankshaft in longitudinal axial section.
• Figures 2 to 7 show alternative ways of arranging the soldering deposit.
• FIG. 8 shows a cross section along the line VIII-VIII of FIG. 1.
• a crankshaft consists of a number of cheeks 1,
• the section shown is made up of four individual pieces A, B, C, D, which are identified by different hatching. Each of these pieces comprises a cheek 1 and a part of both an axle pin 2 and a crank pin 3.
• the individual pieces are hollow to lighten the weight, insofar as the required strength permits and are provided with finished bearing surfaces 4. They are inserted into one another before soldering, the inner part in each case (B in FIG. 8) having been knurled on its outer surface; the knurling process has deformed the surface (see FIG. 8) in such a way that elevations 5 and depressions 6 have arisen, the distance between them being a few tenths of a millimeter.
• the elevations initially go beyond the internal dimension of the outer part (C in FIG. 8), but are partially deformed back when pressed in. Since the outer diameter of the inner part in the non-knurled state is smaller than the inner diameter of the outer part, the depressions 6 remaining between the elevations 5 are also not filled in again when the pieces are pressed in and remain as a soldering gap. Due to the press-in process individual pieces A, B, C, D immovable in the right
• solder 7 Orientation connected to each other and can be brought into the soldering furnace immediately and without the aid of support structures after introducing solder material 7 at a suitable location. There, the solder 7 liquefies and, due to the capillary action, pulls into the gap 6, filling it. Because of a certain oversizing of the amount of solder, the excess finally flows out of the outer end of the solder gap 6 (in the example i a fillet 8). This excess is visible during an optical inspection of the crankshaft and indicates that the soldering in the entire area of the soldering gap 6 has been carried out correctly.
• the adjacent parts of the bearing surfaces 4 are covered with a layer 9 (shown in an exaggerated thickness) of a solder-repellent material (e.g. a metal oxide ceramic).
• a solder-repellent material e.g. a metal oxide ceramic.
• Copper and nickel-based solders are suitable as solders known to the person skilled in the art and appear suitable for carrying out the process.
• FIGS. 2 to 7 show different possibilities of how the ring-shaped solder is expediently arranged in relation to the pieces to be connected to one another.
• the pieces A, B, C, D to be inserted into one another are expediently provided with conical stop faces 10, by means of which the parts are automatically centered on one another during assembly and the insertion is facilitated. If the surfaces 10, as shown in FIG. 1, also form the stops that limit the introduction, it is advisable to provide these surfaces with knurling 5, 6 at one of the partners, in spite of the zero gap that arises on these surfaces the solder can reach the extreme end of the gap 6.
• FIGS. 2 and 3 offer the possibility of using the solder 7 only after the parts have been joined.
• the embodiment according to FIG. 2 is the simplest, while in the case of that according to FIG. 3 it must be ensured that the part of the
• soldering gap 6 is not designed as a zero gap, since otherwise the flow of solder at this point would be severely impeded and possibly would not fill the entire remaining gap 6.
• the solder ring 7 must be introduced before parts A, B, C, D are joined; on the other hand, there is the advantage that it cannot be lost when the crankshaft blank is subsequently handled.
• care must again be taken to ensure that the gap part denoted by 61 does not form a zero gap or is otherwise also provided with knurling. If, in the embodiment according to FIG. 6, the solder is arranged at the upper position shown in dashed lines, it must be taken into account that the part of the soldering gap 6 designated by 62 has to be eliminated when assessing the strength of the connection, as a result of a lack of

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Citations (5)

• 1988
  • 1988-09-07 DE DE19883830432 patent/DE3830432A1/de not_active Withdrawn
• 1989
  • 1989-08-28 WO PCT/DE1989/000563 patent/WO1990002885A1/de unknown

Patent Citations (5)

Non-Patent Citations (1)

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