EP0661137B1 - Apparatus for rolling engine crankshaft journals, tool and method for rolling of adjacent and staggered crankshaft journals - Google Patents

Description

Background of the Invention

This invention relates to deep rolling of fillets of engine crankshafts or other annular areas of metallic workpieces that have high stress loads are exposed and in particular to a new and improved machine Rolling tool and a method for simultaneously deep rolling the fillets of angular offset, adjacent crank pin seats to their fatigue strength and Increase surface hardness.

Description of the prior art

For internal combustion engines such as V6 engines found in many modern automobiles is the left row of cylinders of the engine block with respect to the right row set slightly forward. This cylinder arrangement allows the connecting rods of the paired, arranged in the cylinders in opposite rows of the engine Pistons side by side with adjacent or adjacent seat sections to connect a conventional crank pin. To achieve an even ignition, where the cylinders fire at an angular interval of 120 °, the center line each of these seat portions facing away from the axis of rotation of the crankshaft at an angle from each other be spaced and include, for example, an angle of 30 °. Other V engines with different cylinder arrangements, for example V10 engines have a different crank pin seat offset.

Due to the design of the crankshaft and this offset of the crank pin seats can the crankshaft in operation on the fillet areas of the crank pin seats in such Dimensions are loaded that the fillets tear and bending of the crankshaft can occur during engine operation, so that the life of the crankshaft considerably is reduced. To improve durability, the crankshaft can be enlarged of the crank pin seat diameter and by heat treatment (quenching and Tempering) of the crankshaft in order to increase its form and fatigue strength will. The fatigue strength and durability of crank pins and main bearing seats can by deep rolling compressive stresses into the metal of the annular fillets significant between the pin seats and the adjacent counterweights or bearing shells increase.

Then there are the automobiles and their components for weight reduction and improvement fuel efficiency will be reduced, smaller engines and crankshafts needed. To the fatigue strength and durability of reduced crankshafts too will improve the deep rolling of fillets and other annular adjacent ones Areas increasingly important, with improvements in fatigue strength between 20 and 150%.

Prior to the present invention, fillet rolling was performed on angularly offset seats Crank pin difficult and time consuming, especially since the fillets of neighboring ones and angularly offset crank pin seats independently of one another with high-load fillet rolling machines rolled in a time-consuming and lengthy process had to. The side loads from the independent rollers were able to self-center of the rolling tool and moving away from the fillet so that the desired grooved compressive stresses and fatigue strength are reduced or not were achieved.

Verfahren und Vorrichtung zum Glattwalzen und Festwalzen von mehrhübigen Kurbelwellen"; 4,785,537, veröffentlicht am 14. Dezember 1984 für Maschine zum maschinellen Bearbeiten von Kurbelwellen"; und 4,766,753, veröffentlicht am 30. August 1988 für Walzvorrichtung zum Oberflächenhärten oder Glätten".Examples of devices, tools and methods generally associated with the present invention are prior art patents such as US Patents 5,138,859, issued August 18, 1992 to

Method and apparatus for smooth rolling and deep rolling of multi-stroke crankshafts "; 4,785,537, published December 14, 1984 for Crankshaft Machining Machine "; and 4,766,753, published August 30, 1988 for Rolling device for surface hardening or smoothing ".

In contrast to the above-mentioned patent disclosures of the prior art the present invention relates to a new and improved fillet rolling method, Tool and device for rolling, suitable for the new and improved, simultaneous deep rolling and permanently hardening the fillets of angularly offset crank pin seats and other ring spaces.

The upper tool of this invention includes side-by-side main housings, in which backup rollers are attached. Located at the bottom or processing end of each case there is a cage carrying an angled or inclined processing roller, which is in rolling contact with a peripheral surface of the support roller, so that on the housing applied load over the back-up roller onto the inclined metal working roller and from there on the granular structure of the metallic crankpin grooves, which for the purpose of permanent hardening are to be rolled.

The crankshaft, the pin grooves of which are to be rolled, is in a chuck or another workpiece holder, and is about its axis of rotation by a Motor driven, which is connected to drive the chuck so that the processing rollers roll the ring-shaped grooves of the crank pins under pressure.

A ring-shaped thrust bearing unit that is operatively arranged between the tool housings with cage keeps their alignment in parallel planes while being relative to each other and rotated around the axis of an engine crankshaft. It is very important that this Thrust bearing unit represents a device that the resulting directed against each other Side pressure forces caused by the opposite and outwardly inclined rollers generated, picked up and canceled during the rolling process. If the against each other directed side pressure loads are lifted, the tool itself remains then in the middle when the seat sections of each pin are angularly offset from one another.

In addition to the upper tool, a pair of lower support tools are provided, which each have two back-up rolls that hold the pin seats when the work rolls of the upper tool, roll in the fillets of the piston pins. These backup rolls are arranged between the pin seats around the rolling loads transmitted by the pin seats record so that no significant bending loads on the crankshaft to be rolled be applied.

The top and bottom pairs of tools are each in parts of the top and bottom Claws are held with an oscillating clamp structure, each comprising a pair of levers, which are rotatably connected to each other by an intermediate pivot. Hydraulic Drive cylinders that connect the end portions of the clamp levers together so operable that the machining force by the driven expansion of the cylinder generate, which is transferred to the fillet rollers via the claws. To a single one The clamp construction for enables the operation of every single pair of claws a swinging operation "held by swing arms which turn backwards and swing forward or swing like a pendulum during deep rolling.

In this invention, a new and improved method of fillet rolling is disclosed metallic component such as a pin seat of a crankshaft provided, in which angularly offset, annular fillets of adjacent tenon seat sections at the same time are rolled to expose the metal of the fillets to compressive stress and thereby increase the fatigue strength of the component.

Another object of the invention is to provide a new and improved metal rolling machine, the pairs of rotatably connected Lever with metalworking rollers included in a tool that in Clamping claws of the levers are arranged around an axis of an internal combustion engine crankshaft commute to pairs of staggered, annular fillets of staggered Roll down the journal of the crankshaft.

Another object of the invention is that this is a new and improved tool for rolling annular and angular offset processing areas such as Fillets of crankshaft journal seats provides the adjacent, rotatable relative to each other housing, each a fillet roller so mounted thereon that laterally spaced and angularly offset fillets are simultaneously rolled and metalworked can to improve their fatigue strength.

These and other features, objects, and advantages of this invention will become more apparent by the following detailed description and by the drawing figures, the following demonstrate:

Description of the drawing figures

Figure 1

Fig. 10 is a schematic front view of a fillet rolling machine, some of which are shown in Figs Basic principles of fillet rolling used in the present invention represents;

Figure 1A

Figure 1 is an enlarged view of a portion of Figure 1, showing how that Tool rolls the fillets of a crank pin seat;

Figure 1B

is a pictorial view of a section of a crankshaft side by side connecting rods attached to adjacent pin seats;

Figure 2

is a schematic view of a portion of the machine of Figure 1, and essentially cut along lines 2-2 from Figure 1;

Figure 3

Fig. 10 is a pictorial view of a preferred embodiment of a fillet rolling machine according to the invention;

Figure 4

3 is a side view of the fillet rolling machine;

Figure 4A

10 is a pictorial view of a portion of a crankshaft for an internal combustion engine; the angularly offset and side-by-side crank pin seats having;

Figure 4B

is a graph of the angular misalignment of the crankpin seats of the crankshaft Figure 4A;

Figure 4C

Figure 4 is a sectional view taken along lines 4c-4c of Figure 4;

Figure 5

Fig. 12 is an end view with parts of the fillet rolling machine broken away FIG. 4, seen from the perspective of arrow A from FIG. 4,

Figure 6

is an enlarged side view of the in the fillet rolling machine of the Figures 3, 4 and 5 used tool;

Figure 7

5 is a sectional view of the tool of FIG. 5 taken along lines 7-7 from figure 6, but with part of the engine crankshaft and the supporting lower one Tool added;

Figure 8

is a side view of the lower support tool used for the fillet rolling machine from Figure 4 is used;

Figures 8A and 8B

are sectional views of the lower support tool, namely cut along lines 8A-8A and 8B-8B of Figure 8;

Figure 9

Fig. 3 is a diagram showing the rolling of angularly offset trunnions according to of this invention.

Description of the drawing figures Detailed description

The drawing will now be discussed in more detail. Figures 1 and 2 show diagrammatically Sections of a metalworking machine 10 that do some basic work hardening the fillets of crank pins 12 of a crankshaft 14 for an internal combustion engine represent. The crankshaft has a front end 16, which is in a chuck 18th is attached, and a flange end 20, which is held by a centering mandrel 22 of the machine becomes. The crankshaft can optionally and rotatably about the horizontal axis B of one Drive motor 24 are driven by a retaining ring 26 on the machine housing is held and connected to the chuck driven by the drive shaft 28 is. Each of the crank pins 12 has laterally arranged and coaxial seat sections 30 and 32 (Figure 1A), the cylindrical bearings for the connecting rods 34, 36 (Figure 1B) from opposite Form pistons in the left and right cylinders of a V-engine block.

Given that the pin seat portions 30, 32 during engine operation exposed to high voltage loads, these are reinforced in various ways, such as. by increasing the pin seat diameter and hard rolling hardening it laterally spaced, annular fillets F, F ', being high and concentrated Rolling forces are directed to the annular fillet areas of the crankshaft. A such rolling creates compressive stresses in the metal of the crankshaft grooves, which can reach a depth of 4 mm, for example.

As shown in FIG. 2, this is done in machine 10 by upper and lower tools 40 and 41 achieved that functional in the claws 42, 43 facing each other load applying claw assembly 44 are attached which forms part of the machine and is supported for operation by a flexible support 45.

The upper tool 40 has a pair of oscillating rollers 46, 46 'made of hardened steel or other material, which are essentially about mutually inclined axes A and A 'rotate to with the laterally spaced fillets F, F' which are the annular contact surfaces between the pin and the adjacent counterweights or bearing shells form the crankshaft, intervene and roll. The lower tool 41 has angularly spaced support rollers 47, which form bearings and support for the crank pin, while the crankshaft 14 is rotatably driven about its axis B and the fillets are rolled will. The rolling pressure becomes hydraulic through the expansion force of a hydraulic cylinder 48 applied, the functional between the extending ends 49, 50th of the upper and lower claw arms 51, 52 is connected, which is in a middle position of the Claw arm lengths are rotatably arranged by a pivot pin 53 held in a fork shoe are. This arrangement provides the mechanical advantage of claw closing force amplified by the expansion force of the hydraulic cylinder 48 on the Claw assembly is exercised.

In an automatic machine and made possible by the flexible support 45 upper and lower claws and their tools are supported so that during rolling oscillate around the axis of the rotating crank pin. The one applied by the rollers 46, 46 ' Rolling force can be exerted by cylinder 48 while driving the crankshaft can be increased and decreased by the motor 24 to concentrated annular residual stress patterns into the metal of the fillets F, F 'during engine operation belong to the most loaded cutting surfaces of the crankshaft. The The size of the pressure as well as the number of rolling processes of the fillets can be selected in order to achieve an optimized fatigue strength.

Such rolling processes, tools and machines that are satisfactory for many types of crankshafts are no higher standards for improved strength and for a higher production volume of crankshafts 54 with crank pins 55, which are angularly offset and adjacent crank pin seats 56, 58 (Figure 4A), as used in many modern V-engine blocks. Around To meet such higher standards, the present invention has been developed which are exemplified in a first preferred embodiment in FIGS. 3 to 9 is.

As in the pictorial view of Figure 3, the side view of Figure 4 and the front view 5, the machine 60 of this invention has a pair of side by side arranged stands 62 and 64 which extend upward from a base 66, those on a support plate 70 adjustable by tongue and groove or another Rail construction is attached. This rail construction and an attached one Drive cylinder 72 allows the machine and its tools to be easily engaged to bring the angularly offset pin seats 56, 58 of the crankshaft 54 and back again, if this as in Figure 1 in a driven chuck and a centering mandrel is clamped.

At the top of stands 62 and 64 is an elongated, transverse, cylindrical one Bracket 74 held. A rotary shaft 76 extends axially through the cylindrical Bracket, 74 and has a connector end that pairs the ends of right and left of swing arms 78, 78 'and 80, 80' hanging from it. The connection ends The swing arms carry pivot pins 82 and 84, which are the upper right and left Claw arms 88 and 90 located between their respective pairs of swing arms extend, rotatably connects. The upper right claw arm 88 is with the lower right claw arm 92 with a central, extending in the horizontal direction Bolt 93 rotatably connected. This bolt is held by a fork shoe 94 the ends of which extend upward from the lower claw arm to the upper Clasp claw arm. This construction represents a right hand clamp assembly 95 ready. The upper left claw arm 90 is similarly through a fork shoe and a pivot pin 96 connected to the lower left claw arm 97 to one to provide left claw assembly 98. The right and left claw arm fork shoes between them take the downward-extending lower sections of the upper Claw arms open so that the top and bottom claw arms of each pair are coplanar with each other are when they are rotatably connected to each other with the bolts 93 and 96.

The upper and lower claw arms of each claw assembly are made from flat metal plates and have rearwardly extending portions 100, 102 and 104, 106 on, the connection points for the fork shoes and the bolts 108, 110, 112 and 114 for form the right and left hydraulic drive cylinders 116, 118. Every drive cylinder has a cylinder tube in which a piston 120 or 122 is functionally arranged. Controls or regulations 123 control or regulate the supply and discharge of pressure fluid to the cylinders below and above the pistons, around the expansion and contraction strokes the cylinder to cause the claws to extend forward Close or open 124, 126 and 128, 130 of the right and left pairs of claw arms. For example, by supplying pressure fluid to the pressure chambers above the piston and by pushing fluid out of the chambers below the piston Cylinder and pistons back, rotating the claw arms around bolts 93 and 96, so that the claws move away from each other to an open position. This allows the tool to be in a machining position with the crank pin seats 56, 58 moved or the crankshaft can be removed from the tool.

Figure 4C illustrates a spaced apart arrangement that includes the relatively movable upper claw arms 88, 90 holds parallel and in a laterally spaced relationship to each other. This The assembly includes a cylindrical spacer 111 with a head which is cylindrical Shaft 111 ', which extends axially through a corresponding fine-fit bore 113 in the upper left arm 90 and through a large bore 117 in the right upper arm 88 extends. On the upper arm 88 are inner and outer brass wear rings 121, 121 'secured by screwed fasteners.

An enlarged annular washer 125 attached to the outer end of the retention shaft is secured by a continuous bolt 133, is laterally in contact with the outer brass ring.

The upper claw 124, 128 of each upper claw arm 88, 90 provides a seat for a mortise mill tool assembly 134 ready, as best shown in Figures 6 and 7. The Chamfer rolling tool assembly 134 includes a pair of tool housings 136 and 138, which are mounted in a lateral and relatively rotatable relationship. Locking clips as in reference numbers 131 and 132 secure the housings to the corresponding ones upper claws 124 and 126.

Each of the housings is broadly the same, so only the housing 136 in detail is described. Housing 136 includes an outer rectangular main body 140, that has been milled or otherwise machined to provide an annular receptacle 142, which receives a backup roller 144, which passes through an inner cylindrical Tread 148 fitted needle bearing 146 is rotatably supported, the tread 148th is supported on a large, axially extending hub 150, which at 152nd is stepped to into the annular bore in the outside of the main body 140 fit. The housing 136 is on its inside with an annular closure plate 154 closed, which is fixed to the housing with screws 156. The closure plate 154 has an enlarged annular receptacle 158 for receiving the inner end of FIG cylindrical hub 150.

An annular cage of needle thrust bearings 160 is on an inner shoulder of the closure plate concentric with the hub seat 150 between the backup rolls and the closure plate arranged and suitable for the resulting from the rolling of the fillets Transfer side loads to an annular ball bearing unit 162 that is functional is arranged between the tool housings 136 and 138. The spherical balls 163 of this ball bearing unit are held for rotation in cages that are functional are arranged in a holding plate 164 on a central hub 166, which is in axial Direction extends from the locking plate 168 of the adjacent tool housing 138. During operation by the driven rotation of the crankshaft, the spherical ones roll Balls 163 in ring-shaped truncated bearing treads 170, 172 of the combined Locking plates 154 and 168.

Each housing 136, 138 has a pair of L-shaped processing roller mounts 176, 178 and 180, 182 on which are adjustable at its lower end by screws 184, 184 'are attached. These brackets have inner ends that are recessed around To form cages 186, 188. When the brackets are attached to their housings, support the cages are substantially hardened machining rollers 190, 192 for oscillating rotation axes 194, 196 inclined upwards and outwards, so that the machining scope of the rolls to the fillets F and F 'to be rolled of the crank pin seats 56, 58 extends. The processing rollers 190, 192 stand by the annular, stepped shoulders 197, 198 of the support rollers 144, 199 of the housings 136, 138 in contact so that the claws, when clamped, as shown in Figure 7, a rolling force on the fillets F, F 'transferred.

Since the bearing unit 162 is arranged between the two housings 136, 138, the side loads S, S 'resulting from the fillet rolling process are effectively neutralized. Thereby ensures that each of the fillets conforms to the requirements is rolled down and the tools do not move away from the fillets.

The fixed support tool that attaches to the lower claw of each claw assembly is formed by first and second fixed support units 200 and 202 that are functional e.g. by adjustable clamps 204, 206 on the lower claw of each lower Claw arms are attached. Because these units are broadly the same construction only unit 200 is described in detail. The unit 200 has one substantially rectilinear main body 203 with outer grooves 204, 206 which the Pick up the edges of the lower claw arm 92 plate. Secure terminals 205 and 207 the unit 200 is able to rest on the lower arm.

Tool 200 has a pair of spaced rollers 208 and 210 that are rotatable are attached by needle bearings 209, 211 to hubs 212, 214 which are laterally spaced Side plates 216, 218 are held. Screws 219 secure the side panels to the Main body 203.

To stabilize the pairs of claw arms, brackets 226 attach to the cylindrical Bracket 74 attached pneumatic cylinders 222, 224 used. The cylinders 222 and 224 have pistons with connecting rods 228, 230, which extend downwards, and which are rotatably connected to the upper claw arms by brackets 230, 231 to stabilize the operation of the arms when the fillets are rolled.

Element 232 is a rotor mounted on rotatable shaft 76, which is connected to gripper 233 works together and thus forms a disc brake 234, which can be used optionally can to stop the pair of claws in any predetermined position.

For rolling the fillets of the offset pin seats, the crankshaft 54 is in the Chuck and the centering mandrel used as shown in Figure 1. Then it will Tool from Figures 3 to 8 moved to a position in which the processing rollers Touch the fillets F, F 'of the offset pin seats 56, 58 as shown in FIG. The Claws are closed under the load of the expansion cylinder so that the processing rollers 190, 192 with the fillets F, F 'with a preselected rolling force.

The drive motor 24 is then driven so that the chuck turns the crankshaft drives its axis of rotation, namely axis B, in rotation. This rotation causes the offset pin seats 56, 58 on an annular path or path in a clockwise direction move around the axis B of the crankshaft when the shaft is rotated (see Figure 9). The clamping claws, which are clamped to the offset pins, follow the rotation path of the Cones. If the pins rotate about the axis B of the crankshaft, the pendulum swings accordingly each claw assembly and the support arms 78, 78 ', 80, 80' swing backwards and forward like a pendulum allowing this movement.

The rolling force of the claws transmitted to the processing rollers can be increased or otherwise can be varied in order to simultaneously deep-groove the fillets and hardening work to effect the metal of the fillet areas and thereby an improved To achieve fatigue strength of the fillets and the crankshaft. Because the crankpin offset from each other, each set of arms follows its connected crank pin, so that the grooves of the crank pin are rolled at the same time even if these are angularly offset. When rolling, suitable lubricants are applied to the Fillet areas are applied to reduce friction and improve rolling.

After the rolling of the fillets is completed, the drive cylinders become Opening the claws contracted so that the finished crankshaft is removed from the machine can be.

Although only a pair of roller claws have been shown and described, it will understand of itself that for a 6-cylinder engine with three offset crank pins for even ignition of the engine corresponding to three pairs of claw mechanisms for Rolling the fillets of the crank pins in a constructed according to the figures Machine are necessary.

Since a preferred embodiment of the invention has been shown and described, other embodiments will become apparent to those skilled in the art. Accordingly this invention is not limited to what has been shown and described, but by the following claims.

Claims (5)

1. An apparatus for permanent workhardening of a ductile iron crankshaft (54) for a combustion engine by simultaneous machining of the material of adjacent grooves, directed toward each other, of offset cylindrical crank shaft journal bearings with center axes running parallel to the axis of rotation of the crankshaft, comprising: mounts (74), rocking arms (78, 78', 80, 80'), pivot pins (76) that functionally connect the rocking arms and the mounts, first and second sets of clamping claws (95, 98), where each set of claws has a bottom claw (92, 97) and a top claw (88, 90) and a pivot pin (93, 96) that attaches the bottom claw (92, 97) and the top claw (88, 90) to each other so they can rotate, additional pivot pins (82, 84) for connecting the top claw (88, 90) to the rocking arm (78, 78', 80, 80'), where each of the sets of claws (95, 98) has a pair of claws (124, 126; 128, 130) having a tool mount (136, 138) for mounting the tool (190, 192) for simultaneously machining the material of the grooves (F, F') of the crankshaft journal bearings (56, 58) directed toward each other by rotating the crankshaft (54) about the axis of rotation (B), so that the rocking arm (78, 78'; 80, 80') supporting the corresponding set of claws (95, 98) swings on the pivot pin (76) and oscillates at an angle, while the claws (88, 90) of each of the sets of claws (95, 98) move about the corresponding crankshaft journal bearing (56, 58), a force-generating device (116, 118) which acts on each set of claws (95, 98) with a closing force, and a bearing (200, 202) which neutralizes the forces exerted upon the rolling tools (190, 192).
2. A use of the machine according to claim 1 for rolling treatment of adjacent bearing seats (56, 58) and laterally adjacent grooves (F, F') of a shaft, where the bearing seats (56, 58) are offset at an angle to each other, comprising the process steps:

   loading the shaft (B) into the rolling machine (60),

   arranging rolling wheels (190, 192) on the groove areas (F, F') between the shaft and the components,

   applying a load to these rolling wheels (190, 192),

   rotating the shaft (B) relative to the rolling wheels (190, 192) so that the wheels come in contact with the groove areas (F, F') and at the same time roll the annular areas whose center axes are offset to each other.
3. A rolling tool (134) for simultaneous rolling of adjacent annular machining locations of cylindrical parts offset at an angle to each other and grooves laterally adjacent to them, comprising a first and second casing (136, 138), where each of the casings has a cage (186, 188) on its lower end, with a hardened machining roll (190, 192) which is functionally arranged in this cage (186, 188) to roll and simultaneously workharden the adjacent annular working areas and the adjacent grooves, with a bearing construction (162) which is functionally arranged between the casings (136, 138) and enables the casings to rotate relative to each other on essentially parallel planes and absorb the oppositely directed side loads resulting from the simultaneous rolling of the offset machining locations.
4. A rolling tool according to claim 3, where the cylindrical parts are journal points (56, 58) of crankshafts (54).
5. A rolling tool according to one of claims 3 or 4, where the bearing construction (162) absorbs oppositely directed cross loads resulting from the rollers of the offset grooves.

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