WO2019058004A1

WO2019058004A1 - Equipment and method for twisting crankshafts

Info

Publication number: WO2019058004A1
Application number: PCT/ES2017/070631
Authority: WO
Inventors: Francisco LARRUCEA DE LA RICA; Virginia MANSO RODRIGUEZ
Original assignee: Cie Automotive, S.A.
Priority date: 2017-09-25
Filing date: 2017-09-25
Publication date: 2019-03-28
Also published as: ES2893856T3; EP3689486A1; EP3689486B1

Abstract

The present invention relates to equipment and a method for twisting crankshafts (A), comprising three modules (1), each comprising an upper tool (1') and a lower tool (1"), both having an inner face by means of which they face one another, each tool (1', 1") having a cavity in its inner face, the geometry of which corresponds to the outer shape of a crankpin of the crankshaft (A) to be twisted, such that the cavity defined by the facing tools (1', 1") of one and the same module (1) corresponds to the entire outer shape of the crankpin, where the tools (1', 1") of each module (1) are arranged on a supporting element (2) that can rotate independently with respect to an axis of rotation (3) coinciding with a longitudinal axis (Α') of the crankshaft (A) when the crankshaft (A) is arranged in the equipment, where the tools (1', 1") of each module (1) can only effect a linear movement with respect to the supporting element (2) in which they are arranged, this linear movement being perpendicular to the axis of rotation (3).

Description

EQUIPMENT AND METHOD TO REVIVE CRANKSHAFTS

D E S C R I P C I O N

TECHNICAL FIELD OF THE INVENTION

The present invention has application in the mechanical industry, and more specifically in the field of equipment for the manufacture of crankshafts.

BACKGROUND OF THE INVENTION

At present there are different configurations or types of crankshaft, determined by the characteristics of the engine that said crankshaft is part of. The main characteristic of the crankshaft is the number of crankshafts, which corresponds to the number of cylinders that the engine has. In addition, the crankpins can be arranged according to different angles depending on their number, in correspondence with the number of cylinders of the engine and their arrangement, either in line, for motors of 3 to 6 cylinders, or in V, for motors of 6. and 8 cylinders.

In some cases, one of the final operations in the manufacture of crankshafts, once you have the crankshaft forged and the excess burr has been cut, is the twist. The twist consists in making a twist with respect to the longitudinal axis of the crankshaft, to place each crankpin in the corresponding angular position. That is to say, by means of this operation, the different cranks are rotated according to the final orientation that they have to have depending on the type of the motor. Crankshaft rolling machines used today are mainly formed by a hydraulic press with a main cylinder, its corresponding frame, an upper base plate and a lower base plate. Usually, the main cylinder of the press acts directly on the upper base plate, to which an upper tool holder is fixed, also known as the upper rear window, which remains fixed. For the rotation of the crankpins, the equipment usually includes two twist trees, located on each side of the lower base plate. Said twisting shafts transmit the rotation to a lower tool holder, and are actuated by two or four twist cylinders. One of the critical aspects that must be taken into consideration in the design of the crankshafts, taking into account the equipment for their manufacture described above, are the tensions derived from the moments that are created by making the twist with the press in two phases, that is, by means of two strokes, one for the action of the main cylinder and one for the revolving cylinders, so there is no simultaneity in the phases. The direct drawback of this aspect is that the operation in two phases carried out in the current equipment implicitly involves considerable deformations, which make a final calibration operation necessary to achieve the required tolerances in the crankshaft, which makes the manufacturing method Furthermore, as can be seen from the previous discussion, a large machinery is required, which is heavy and has a high cost.

For its part, as mentioned above, the twisting tool currently used comprises a split tool consisting of upper and lower lunettes, some fixed and others mobile, that is, they can rotate with respect to the longitudinal axis of the crankshaft , where the mobile lunettes rest on rollers. All lunettes are mounted on a lower base plate and a top base plate. The distances between the lunettes are adjustable, so that the distances and the number of lunettes are fixed to the base plates according to the type of crankshaft to be rotated.

Initially, the forged crankshaft is placed on the inside of the split tooling. When the stroke of the upper moving head of the press starts, the crankshaft is positioned by means of the lower lunettes once the upper head has descended completely and the crankshaft is tied, the twisting process is carried out by turning the lunettes mobiles, which materialize as split discs that rotate at an angle preset by the front twist shaft and the rear twist shaft that incorporates the equipment. The twisted shafts are on both sides of a central axis of the machine and rest on the frame of the press itself. These trees are the ones that transmit the torque to the twist lunettes. The crankpin moored by the movable lunettes, therefore, describe an arc of circumference until it reaches the required angular position. The twist angle is adjusted by adjusting the stroke of the twist cylinder. To mode For example, in the case of crankshafts with 3, 4 or 6 cranks with angles of 120 °, 90 ° or 60 ° respectively, you can make the twist with only two twist trees, so that all the crankpins can be positioned with a certain value of twist angle, that is, different from 0 °. However, in the case of crankshafts with 5 crankshafts and an angle of 72 °, 2 additional winding shafts are required, since only two crankshafts can be positioned with the same angle of twist. Obviously, this complicates the team and the process even more.

Once the twisting process has been completed, the upper head moves back to the top dead center, the lower and upper ejectors being activated simultaneously. The already twisted crankshaft is suspended over the lower ejectors. The lower movable lunettes return to their initial position as a consequence of the lowering of the twist shafts. The mobile half-roofs of the upper head are retracted to their initial position through pneumatic cylinders. From this moment the crankshaft can be removed.

Once the entire process is explained in detail, it is understood that due to the geometric complexity of the required tooling, excessive deformations occur in the twisted crankshaft which makes it necessary to perform a final calibration operation. Said deformations are, to a large extent, due to the drafts that must be made in the tooling, for the opening thereof and to the inherent tensions of the twisting process. In addition, as mentioned, the case of twisting crankshafts of five cylinders, implies an added difficulty, since it is necessary to forge with non-flat partition surface, in addition to being necessary a final twist, which further complicates everything the process.

DESCRIPTION OF THE INVENTION

A first aspect of the present invention relates to a device for turning crankshafts, which allows to reduce the deformations of the twisted crankshaft and simplify the design of the corresponding tooling. The equipment proposed by the invention comprises a tooling comprising at least three twist modules, wherein each twist module in turn comprises an upper tool and a lower tool. The supplies they have an internal face that they can face. Each tool has a cavity in said internal face whose geometry corresponds to a part of the specific external shape of a crankpin to be rotated, so that the cavity defined by the tools facing the same twist module corresponds to the shape complete exterior of the crankpin. That is to say, the shape of the trace of the tooling coincides 100% with that of the crankshaft section.

In this way, there are no significant gaps between the tooling and the shapes of the crankshaft section to be revolved.

For its part, the crankshaft has a longitudinal axis and can be arranged so that a crankpin is housed in the cavity defined by the lower tool of one of the twist modules, preferably one that will not rotate, as explained later. Well, according to the invention, the tools of each twist module are arranged on a support element, where at least two support elements, also called rotation frames, can rotate independently, with respect to speed of rotation. rotation, angle and direction, with respect to an axis of rotation that coincides with the longitudinal axis of the crankshaft when said crankshaft is disposed in the equipment. Likewise, the tools of the same twist module can only perform a linear displacement with respect to the support element in which they are arranged, said linear displacement being perpendicular to the axis of rotation.

In this way, instead of using a press with adapted jaws in which the crankshaft is obtained after several rotations and ascents of the drive, as is done in the state of the art, the invention proposes a modular solution in which all the turns at the same time, that is to say simultaneously, which reduces tensions and gaps, avoiding excessive deformations. What allows to dispense with a subsequent calibration.

In addition, when opening the tools the equipment and the process are much simpler, since in the separation of tools there is a relative movement according to an axis perpendicular to the axis of rotation. In the state of the art the design of the jaws was much more complicated and very high stresses were produced by the complication in the separation phase of the jaws. By saving this the invention makes it possible to make simpler jaws, such as those previously described and even without a subsequent calibration. In the case of the invention, the tools allow their opening in the direction transverse to the longitudinal axis of the crankshaft, after rotation. In the state of the art it was necessary to design the tooling to allow its opening always according to the vertical direction. Therefore, in the case of the invention, the dimensional tolerances of the piece are much tighter, this being what allows to suppress the subsequent calibration process. The possibility is contemplated that the independent turning movement of each support element with respect to the axis of rotation is carried out by means of second driving means.

The load of the crankshaft in the twisting modules can be selected between lateral, from a plane perpendicular to the axis of rotation, and frontal, from a plane parallel to the axis of rotation.

A second aspect of the invention relates to a method for revving crankshafts, comprising using equipment as described above.

The method comprises the following steps:

- arranging a forged crankshaft to be revolved with a crankpin partially housed in the cavity of a lower tool of a twist module which can not be displaced or rotated with respect to the axis of rotation,

- moving radially the tools of each twisting module so that their internal faces are facing each and every crankpin is completely housed in its corresponding cavity defined by the tools of each twisting module faced, (act the first drive means)

- simultaneously rotating each support element, with an independent direction of rotation, although it is also contemplated that the speed, and therefore the angle, will be relative to the axis of rotation in accordance with the angular position required for each crankpin, (Second drive means act)

- moving radially the tools of each twist module so that their internal faces are in the open position and each crankpin is only housed in the module that does not rotate. (Act the first drive means)

- turn the support elements in the opposite direction to the previous one. (Second drive means act)

In this way, tensions are reduced, as already mentioned, taking into account the simultaneity and combination of rotation and displacement movements. In the case of the state of the art there is no combination or simultaneity of turning and longitudinal movements, which causes the crankshaft to suffer more and unnecessary stresses are generated.

DESCRIPTION OF THE DRAWINGS

To complement the description that is being made and in order to help a better understanding of the characteristics of the invention, according to a preferred example of practical realization thereof, an assembly of drawings is included as an integral part of said description. With an illustrative and not limitative character, the following has been represented:

Figure 1 shows a schematic view of a first embodiment of the equipment proposed by the invention, which comprises three twist modules with lateral loading and second hydraulic actuating means.

Figure 2 shows a schematic view of a second embodiment of the equipment proposed by the invention, which comprises three winding modules with side loading and second electrical actuation means.

Figure 3 shows a schematic view of a third embodiment of the equipment of the invention, which comprises three modules of twist with load front and second hydraulic drive means.

PREFERRED EMBODIMENT OF THE INVENTION In view of the figures outlined can be seen how in one of the possible embodiments of the invention the crankshaft reaming equipment (A) proposed by the invention comprises at least three twist modules (1), in the cases represented in figures three, although it is also contemplated that it comprises five. Each twist module (1) in turn comprises a upper tool (V) and a lower tool (1 "), where said tools (V, 1") have an internal face through which they can be faced, each tool having ( V, 1 ") a cavity in said internal face whose geometry corresponds to a part of the external shape of a crank pin (A) to be rotated, so that the cavity defined by the tools (1 ', 1") faced of the same twist module (1) corresponds to the complete outer shape of the crankpin.

As can be seen in the figures, the crankshaft (A) has a longitudinal axis (Α ') and can be arranged so that a crankpin is housed in the cavity defined by the tools (1', 1 ") opposite each other. minus one twist module (1).

In the figures, it can be seen how the tools (1 ', 1 ") of each twist module (1) are arranged on a support element (2) that can rotate independently of an axis of rotation (3) that it coincides with the longitudinal axis (Α ') of the crankshaft (A) when said crankshaft (A) is arranged in the equipment.

In the case of the figures, in any case the supporting element (2) corresponding to the central twisting module (1) does not rotate or move in the direction of the axis of rotation (3), although the invention also contemplates an embodiment in the one that can do it. In short, except in a specific typology, usually there is a doll that you do not have to turn. The tools (1 ', 1 ") of the same twist module (1) can only perform a linear displacement with respect to the support element (2) in which they are arranged, said linear displacement being perpendicular to the axis of rotation (3) For its part, the longitudinal displacement of the tools (V, 1 ") of each twist module (1) is carried out by means of first actuating means (4) mounted on the support element (2) itself.

The independent turning movement of each support element (2) with respect to the axis of rotation (3) is carried out by means of second actuation means.

(5).

In the embodiments shown in FIGS. 1 and 3 the second drive means (5) are hydraulic, while in the embodiment shown in FIG. 2 the second (5) drive means are electrical.

As can be seen from the foregoing, and from the sequences represented in the figures, it is understood that in the case of the invention the de-reeving, that is to say the rotation of the support elements (2) in the opposite direction to the revolution, a Once the required turns have been made, it is done in combination with the ejection / opening, which also allows access to the crankshaft both on the front and on the side, depending on the case.

Figures 1 and 2 show two embodiments in which the load of the crankshaft (A) in the twist modules (1) is performed laterally, that is from a plane perpendicular to the axis of rotation (3). On the other hand, in the embodiment shown in Figure 3, the load is frontal, that is, from a plane parallel to the axis of rotation (3). In any case, access is quick and easy. In view of this description and set of figures, the person skilled in the art will be able to understand that the embodiments of the invention that have been described can be combined in multiple ways within the object of the invention. The invention has been described according to some preferred embodiments thereof, but for the person skilled in the art it will be evident that multiple variations can be introduced into said preferred embodiments without exceeding the object of the claimed invention.

Claims

1. - Equipment for reaming crankshafts (A), characterized in that it comprises at least three twist modules (1), where each twist module (1) comprises an upper tool (1 ') and a lower tool (1 "), wherein said tools (1 ', 1 ") have an internal face through which they can be confronted, each tool (1', 1") having a cavity in said inner face whose geometry corresponds to a part of the external shape of a crankpin (A) to revolve, so that the cavity defined by the tools (1 ', 1 ") facing the same twist module (1) corresponds to the complete outer shape of the crankpin, where the tools ( 1 ', 1 ") of each twist module (1) are arranged on a support element (2), where at least two support elements (2) can rotate independently of an axis of rotation (3) that coincides with a longitudinal axis (Α ') of the crankshaft (A) when said crankshaft (A) is arranged in the equipment, d on the tools (1 ', 1 ") of each twist module (1) can only perform a linear displacement with respect to the support element (2) in which they are arranged, said linear displacement being perpendicular to the axis of rotation (3) .

2. - Equipment according to claim 1, wherein the radial displacement of the tools (1 ', 1 ") of each twist module (1) is performed by first drive means (4) mounted on the support element itself (two).

3. - Equipment according to any of the preceding claims, wherein the independent turning movement of each support element (2) with respect to the axis of rotation (3) is performed by second drive means (5).

4. - Equipment according to any of the preceding claims, wherein the first drive means (4) are hydraulic.

5. - Equipment according to any of the preceding claims, wherein the second drive means (5) can be selected between electrical and hydraulic.

6. - Equipment according to any of the preceding claims, which It comprises three twist modules (1) of which the central unit can not move or rotate with respect to the axis of rotation (3).

7. Equipment according to any of the preceding claims, comprising five twist modules (1) of which the center can not move or rotate with respect to the axis of rotation (3).

8. - Equipment according to any of the preceding claims, wherein the load of the crankshaft (A) in the twist modules (1) can be selected between lateral, from a plane perpendicular to the axis of rotation (3), and frontal, from a plane parallel to the axis of rotation (3).

9. Method for reaming crankshafts (A), comprising using an equipment according to any of claims 1 to 8, wherein the method comprises the following steps:

- arranging a forged crankshaft (A) to be revolved with a crankpin partially housed in the cavity of a lower tool (1 ") of a twist module (1) that can not be displaced or rotated with respect to the axis of rotation (3),

- moving radially the tools (1 ', 1 ") of each twist module (1) so that their internal faces are facing each other and is completely housed in its corresponding cavity defined by the tools (1', 1") of each module of twisted (1) faced,

- simultaneously rotating each support element (2), with independent direction of rotation, with respect to the axis of rotation (3) according to the angular position required for each crankpin,

- radially moving the tools (1 ', 1 ") of each twist module (1) so that their internal faces are open and each crankpin is only housed in the module that does not rotate.

- turn the support elements (2) in the opposite direction to the previous one.