A connecting rod breaking device and method

Abstract: A connecting rod (1) for an internal combustion engine is formed in one piece. The large end (4) is then divided by forcing a wedge (18) into a split mold (17) to separate a bearing cap (3) from the remainder of the connecting rod by fracture. To ensure that the fracture occurs in the correct position and plane (a-a), angled edges of caps (24) are pressed against the outer surfaces of the large end of the rod, in the plane (a-a).

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a device and a method for dividing a bear ing cap from a large end portion of a connecting rod (con'rod) by a fracture process. DESCRIPTION OF THE PRIOR ART The breaking and dividing of the con'rod is as follows: As shown in Fig. 5, a con'rod 1 is made in advance in such a way that a con'rod main body 2 and a bearing cap portion 3 are formed as one piece, for example, by sinter forging, and a notch 5a is made in advance in a face to be divided of the inner surface of a bearing portion 5 on a large end portion side 4. In such a con'rod 1, as shown in Fig. 5 and Fig. 6, a small end.portion 6 thereof is fitted onto a small end reference pin 12 stood on a support stand 11, and further, to left and right seats 3a of the bearing cap portion 3 mounted on a movable plate 14 on the bearing cap portion side, which is provided face to face with a stationary plate 13 on the main body side of the large end portion 4 on the support stand 11, tips 15a of a movable pressing portion 15 are pressed to be in contact and fixed, and further, on the stationary plate 13 on the main body side, an escaping force receiving pin 16 is stood so as to be in contact with a part of a shoulder 4a formed connecting with the bearing cap portion 3 in the large end portion 4 of the con'rod 1, and in such a state, a wedge 18 is forced into a split mold 17 fitted into the bearing portion 5 on the large end portion side, and consequently, the main body 2 and the bearing cap portion 3 have been broken and divided at a part of the notch 5a. Furthermore, reference numeral 19 denotes a guide plate of the movable plate 14, which is fixed on the support stand 11. By the way, a mechanism and a method according to the preamble of claim 1 and claim 7 respectively, in which the notch 5a is automatically formed so that breaking and dividing may securely be performed has been disclosed in Japanese Patent Application Laid-Open No. H6-91438. This mechanism comprises: left and right expansion molds 11, 12 (split mold) provided face to face in the direction in which the main body and the bearing 2 (bearing cap portion) are separated from each other, in a large end hole 2a (bearing portion); a punch 13 (wedge) to be forced into a mid position thereof; and breaking chips 14, 15 arranged with the tips facing to the inner surface of the large end hole 2a (bearing portion), at both ends at right angles to the direction in which the bearing 2 (bearing cap portion) is broken and separated in the punch 13 (wedge), and by forcing the punch 13 (wedge), a load in the breaking and separating direction is given to the bearing 2 (bearing cap portion) or the like, and at the same time, by the breaking chips 14, 15, a concentrated load is applied to the portion to be broken and separated of the bearing 2 (bearing cap portion). Accordingly, the part to be broken and separated can easily be deformed, and it is possible to securely make this part the breaking start point, and in the meantime, this can automatically be performed with no trouble only by forcing the punch 13 (wedge)(reference numerals are those used in the Publication). However, in a mechanism like the one described in the Publication in which a notch is not formed in advance and a concentrated load is applied to the portion to be broken and separated by the breaking chips 14, 15 from the inside of the large end hole 2a (bearing portion), by utilizing the forcing of the punch 13 (wedge) for giving a load in the breaking and separating direction to the bearing 2 (bearing cap portion) or the like, this concentrated load is shockingly applied in some cases, and therefore, as shown in Fig. 7, the breaking and separating (dividing) are finished in the state shown by A, B where the breaking and separating are coming off the line a-a passing through the face to be broken and divided in some cases, and there are some cases where it cannot be used as a con'rod. DISCLOSURE OF THE INVENTION The present inventors have found as a result of research that the breaking and dividing are performed precisely at the face to be broken and divided and with a small deformation, by performing the breaking and dividing in the state where the point to be broken and divided of the main body and the bearing cap portion on the outside of the large end portion of a con'rod is pressed, and have reached the present invention as defined in apparatus claim 1 and method claim 7. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a plan view showing one embodiment of a pressurizing mechanism of a con'rod breaking and dividing device of the present invention. Fig. 2 is a front view showing one embodiment of a pressurizing mechanism of a con'rod breaking and dividing device of the present invention. Fig. 3 is a plan view showing one embodiment of a con'rod breaking and dividing device to which a pressurizing mechanism of the present invention is assembled. Fig. 4 is a front view showing one embodiment of a con'rod breaking and dividing device shown in Fig. 3. Fig. 5 is a plan view of the main part of a con'rod breaking and dividing device having no pressurizing mechanism. Fig. 6 is a cross sectional view of a main part of a con'rod breaking and dividing device shown in Fig. 5. Fig. 7 is a plan view showing one embodiment of a con'rod in which breaking and dividing are not performed at a face to be broken and divided. DETAILED DESCRIPTION The present invention will be described in detail with reference to Fig. 1 to Fig. 4. In Fig. 1 to Fig. 4, reference numeral 20 denotes a pressurizing mechanism of the present invention, and first, this will be described by using Fig. 1 and Fig. 2 showing only the mechanism. The present pressurizing mechanism is arranged on a pair of support blocks 21 fixed in parallel on a support stand 11 as follows: That is, between the pair of support blocks 21 on the support stand 11, a large end portion 4 of a con'rod 1 is fixed such that the line a-a passing through the face to be broken and divided is at right angles to the support block 21, and at the corresponding position of the support block 21 on the extension of the line a-a, a screw hole 21a is formed from the outside and a pressurizing bolt 22 is screwed in, and at the tip of the bolt, an angle pressurizing cap 24 whose tip faces to the face to be broken and divided is attached through a rotatable rod 23. Furthermore, in this case, it can also be composed to connect the rod 23 to a hydraulic operating cylinder (not shown in the figure) instead of the pressurizing bolt 22. Fig. 3 and Fig. 4 show a con'rod breaking and dividing device 30 to which the pressurizing mechanism 20 of the present invention is assembled, and in the longitudinal direction of a support stand 31, a pair of guide rails 33 are fixed to the support stand 31 through pressing plates 32 by bolts 34, and a stationary plate 35 on the con'rod main body side and a movable plate 36 on the bearing cap side are arranged so that they may be caught between these pair of guide rails 33 and may stand face to face. Reference numeral 37 denotes a split mold, and half-round left and right portions 37a, 37b are arranged between the stationary plate 35 and the movable plate 36 formed like a half circle to be in accord with the body portion of the split mold 37, and a flange portion 37c formed at the lower end thereof is free, but a similar flange portion 37d thereof is fixed to the movable plate 36 by a small bolt 38 or a knock pin. Furthermore, in the split mold 37, a wedge hole 39 in which a wedge 18 is forced is formed, and the hole 39 is vertical at the left portion 37a in Fig. 3 and Fig. 4, but it is inclined to fit with the shape of the wedge 18 at the right portion 37b. Furthermore, the flange portions 37c, 37d in the split mold 37 are movably fitted into an elliptic hollow 31a formed in the upper surface of the support stand 31. Reference numeral 40 denotes a small end reference pin stood at a specified position of the support stand 31 to which a small end portion 6 of the con'rod 1 is fitted, and around it, an adjusting ring 41 is provided for keeping the con'rod 1 horizontal. Reference numeral 42 denotes a pressing mechanism on the bearing cap portion side to press the bearing cap portion 3 of the con'rod 1, and is arranged on the movable plate 36, and it is composed such that a length adjusting bolt 46 is screwed at both ends of a support plate 45 attached to the tip of a rod 44 of, for example, a hydraulic operating cylinder 43, and it is fixed by an adjusting nut 47, and in the meantime, at the tip of the bolt 46, a pressing hardware 48 in contact with left and right seats 3a of the bearing cap portion 3 is attached. Reference numeral 49 denotes a clamping plate having a width a little narrower than the width of the large end portion 4 of the con'rod 1, and in the one shown in the figure, on the side to be in contact with the large end portion 4 of the con'rod 1, a semicircular concave portion 49a is formed in accord with the bearing portion 5, and on the opposite side thereof, an elongated hole 49b is formed, and it can be fitted onto a clamping support pin 50 stood at a specified position of the support stand 31. Furthermore, this clamping plate 49 is composed to be pressed from above in Fig. 4, for example, by a hydraulic operating cylinder (not shown in the figure) so as to be fixed, when breaking and dividing the con'rod. In the embodiment of Fig. 3 and Fig. 4, the pressurizing mechanism of the present invention is composed such that a concave portion 32a is formed at a part facing to the opposite part (portion to be broken and divided) of the left and right portions 37a, 37b of the split mold 37, that is, at the corresponding position of the presser plate 32 on the extension of the line a-a passing through the face to be broken and divided, in the pair of presser plates 32 in the con'rod breaking and dividing device 30, and that in the concave portion 32a, an angle pressurizing cap 51 whose tip is facing to the opposite part is slidably arranged so that the cap 51 can advance and retreat by a pressurizing bolt 53 connected to the presser plate 32 by a screw, through a rod 52 rotatably connected to the rear thereof. Next, the operation of the pressurizing mechanism of the con'rod breaking and dividing device of the present invention which is composed as mentioned above will be described by being included in the operation of the con'rod breaking and dividing device. First, after fixing the support stand 31 in the con'rod breaking and dividing device by a means (not shown in the figure), the support plate 45 is lowered to the right in Fig. 3 by the operating cylinder 43 of the pressing mechanism 42 on the bearing cap side in advance. Moreover, the pressurizing bolt 53 of the pressurizing mechanism of the present invention is turned in the loosening direction, and the pair of pressurizing caps 51 are lowered in advance. In this state, as shown in Fig. 3, the small end portion 6 of the con'rod 1 and the bearing portion 5 on the large end portion side are respectively fitted and seated onto the small end reference pin 40 and the split mold 37. By the way, in the inner surface of the bearing portion 5 of the con'rod 1, notches 5a are formed in advance in the face to be broken and divided in accord with the opposite parts of the left and right portions 37a, 37b of the split mold 37. Here, the support plate 45 is advanced to the left in Fig. 3 and Fig. 4 by the operating cylinder 43 of the pressing mechanism 42 on the bearing cap side, and the pressing hardware 48 of the mechanism 42 is pressed to be in contact with the left and right seats 3a of the bearing cap portion 3. Furthermore, the pressurizing bolt 53 of the pressurizing mechanism of the present invention is turned, and the pressurizing cap 51 is advanced in the concave portion 32a through the rod 52, and the tip of the cap 51 is pressed to be in contact with the outside of the large end portion 4 corresponding to the notch 5a in the con'rod 1 and a specified force (about 1 kgf-m) is added. Next, the elongated hole 49b of the clamping plate 49 is fitted onto the clamping support pin 50, and while performing adjustment by using the elongated hole 47b, the concave portion 47a on the opposite side is brought into contact with the left portion 37a of the split mold 37. In this state, the clamping plate 49 is pressed from above and fixed by the operating cylinder (not shown in the figure) or the like. Here, as shown in Fig. 3 and Fig. 4, if the wedge 18 is forced into the wedge hole 39 of the split mold 37 by pressurizing means (not shown in the figure), the bearing cap portion 3 is broken and divided from the face to be broken and divided, and it separates from the main body side and moves together with the right portion 37b of the split mold 37 and the movable plate 36 on the bearing cap side, while making the support plate 45 of the pressing mechanism 42 on the bearing cap side or the like retreat to the right. At this moment, a crack caused from the notch 5a rapidly progresses while being directed to the pressurizing point at the tip of the cap 51 of the pressurizing mechanism of the present invention, and the bearing cap portion 3 is broken and divided along the line a-a passing through the face to be broken and divided. Furthermore, at this moment, the deformation near the bearing portion 5 is small. Therefore, in the pressurizing mechanism of the con'rod breaking and dividing device according to the present invention, when a wedge is forced into the bearing portion on the large end portion side through the split mold to break and divide the main body and the bearing cap portion, the directing thereof is performed so that the main body and the bearing cap portion can be broken and divided precisely at the face to be broken and divided, and in the meantime, there is such an effect that breaking and dividing are easily performed so that the deformation near the bearing portion can be made minimum.

Claims: A connecting rod breaking and dividing device for breaking and dividing a connecting rod which includes a bearing cap portion (3) and a main body (2) connected to the bearing cap portion as one piece, into the bearing cap portion (3) and the main body (2), comprising: a wedge (8) which is forcible through a split mold (37a, 37b) insertible into a bearing portion including the bearing cap portion (3) on a large end portion of the connecting rod, characterised by a pressing mechanism (20) to press the point on the outside of the large end portion (4) at which the connecting rod is to be broken and divided. A device according to claim 1, further comprising: a clamping plate (49) which is composed to be pressed so as to secure the connecting rod when breaking and dividing. A device according to claim 1 or claim 2, wherein the pressing mechanism (20) is composed to perform pressing through an acute-angled member (24, 51). A device according to claim 3, wherein the position of the acute-angled member (24,51) is adjustable. A device according to claim 4, wherein the position of the acute-angled member (24, 51) is adjustable by means of a screw mechanism (22, 53). A device according to any of claims 3 to 5, having two said pressing members, one for each point on the outside of the large end portion (4) at which the connecting rod is to be broken and divided. A method of dividing a bearing cap portion (3) from a connecting rod (1) by fracture, in which a wedge (18) is forced into a divided mold (17) inserted in the large end portion (4) of the connecting rod to fracture the rod along a predetermined plane (a-a), characterised in that pressurising caps (24, 51) are forced into contact with opposite sides of the large end portion rod at positions in the said plane (a-a) during fracture of the rod. A method according to claim 7, wherein the pressurising caps have acute-angled edges engaged with the large end portion (4) in the plane (a-a). A method according to claim 7 or 8 wherein notches are formed in the inner surface of the large end portion in the said plane (a-a).

Inventors: HIROTSUGU ZUSHI, HIROYUKI MATUOKA, KATUAKI AIHARA, TOSHIO WATANABE, HIROTSUGU, ZUSHI, HIROYUKI, MATUOKA, KATUAKI, AIHARA, TOSHIO, WATANABE, Hirotsugu, Zushi, Isuzu Motors Limited, Hiroyuki, Matuoka, Isuzu Motors Limited, Katuaki, Aihara, Isuzu Motors Limited, Toshio, Watanabe, Isuzu Motors Limited
Applicants: ISUZU MOTORS LTD, ISUZU MOTORS LIMITED
Application year: 1999
Main classification: B23D31
IPC codes: B23P17, F16C9, F16C7, B23D31