JPS61165007A - Connecting rod - Google Patents

Abstract

PURPOSE:To satisfactorily prevent looseness of a bolt by providing a solid part around the through hole of a block to give sufficient compression rigidity so as to enable the bolt to be elongated sufficiently. CONSTITUTION:A connecting rod is joined with a cap 20 by screwing a bolt 172 and a nut 174 with each other. The bolt 172 has a sufficient length and a part around a through-hole in a block 26 is solid and has sufficient compression rigidity. With the bolt 172 tightened, it can be expected that the bolt is elongated sufficiently, whereby satisfactorily preventing looseness of the bolt 172.

Description

TECHNICAL FIELD The present invention relates to a connecting rod that connects a piston and a crankshaft of a reciprocating engine.

[Prior art] A connecting rod generally has an annular small-diameter end that forms a pin hole through which a piston pin is inserted, and a semicircular end that receives a crank pin by fixing a cap that is separate from the connecting rod. It has a bifurcated large-diameter end with a circular bearing concave surface and a connecting part that connects the small-diameter end and the large-diameter end, and such connecting rods generally require high strength and durability. Because of this, it is common to have a solid structure by die forging.

On the other hand, in recent years, in order to increase the mass production of connecting rods or to improve engine performance by reducing the weight of connecting rods, connecting rods have been manufactured by applying plastic processing to plate materials, reducing their weight and manufacturing costs. Unexamined Japanese Patent Publication No. 5
7-18809 Several proposals have been made, including now,
The present applicant also previously proposed a manufacturing method in Japanese Patent Application No. 59-55484.

The method disclosed in JP-A No. 57-18809 involves forming a longitudinal member having a U-shaped cross section by pressing a plate material, and forming the longitudinal center of the member with the back surface of the U-shape inward. By curving it, an annular small-diameter end is formed, and the parts adjacent to the center are welded to each other at the back surfaces of the U-shape to form a connecting part forming an H-shaped cross-sectional shape. The ends opposite to the side connected to the small-diameter end of the part are curved outward in opposite directions to form a large-diameter end having a bearing concave surface for receiving the crank pin.

In addition, the method of Japanese Patent Application No. 59-55484 includes a shrink flange forming step in which the flanges (both side wall portions) of a member having a U-shaped cross section are contracted, and this step tends to cause wrinkles in the material. In view of this difficulty, the portions requiring this shrinkage flange forming are formed in advance by drawing.

Problems to be Solved by the Invention These methods make it possible to manufacture lightweight and highly rigid connecting rods, but since the large-diameter end has a U-shaped cross section, It will be combined with the cap at the plate-shaped part that forms the bottom wall,
Difficult to connect with bolts. When the two are connected by bolts, the force is received only by the portion of the large diameter end tightened by the bolt, and the flange does not work effectively, making it difficult to obtain sufficient strength.

In addition, the bolts used to secure the cap to the connecting rod are subject to loads that vary periodically as the engine operates, and as the engine is repeatedly operated and stopped, the temperature of the connecting rod and bolts decreases to room temperature. Since the bolts are repeatedly fluctuated between high temperature and high temperature, loosening is likely to occur. It is necessary to maintain a state in which a certain amount of tension or more is always applied despite fluctuations in It is difficult to give them a sense of security. Although it is possible to lengthen the bolt to some extent by increasing the thickness of the tightened portion of the cap, even in this case, the tightened portion of the connecting rod must also have a certain thickness.

In addition, even when a female threaded hole is formed in the tightened part of the connecting rod and a bolt inserted from the cap side is attached to the hole, the female threaded hole must have a considerable length in order to obtain sufficient tightening strength. It is necessary that the tightened part has a thickness of a certain value or more.

Note that it is possible to make the bolt longer by forming box-shaped bolt receivers on both sides of the large diameter end, but in this case, it is difficult to form the large diameter end, and the box It is difficult to apply sufficient tension to the bolt because it is difficult to provide sufficient compression rigidity to the shaped bolt receiver.

Therefore, in the method of Japanese Patent Application No. 59-55484, welding is adopted to join the cap and the connecting rod, but once the cap and the connecting rod are welded, the connecting rod can be attached to the crankshaft. Another problem arises in that it becomes impossible to remove the parts from the body, making it difficult to replace, inspect, etc. the parts.

Means for Solving the Problems In order to solve the above-mentioned problems, the connecting rod according to the present invention includes (a) a longitudinal member formed by pressing a plate material and having a U-shaped cross section; The central portion in the longitudinal direction is curved with the back surface of the U-shape inward to form an annular small-diameter end, and the back surfaces of the U-shape are welded to each other in a portion adjacent to the center portion. thereby forming a connecting portion having an H-shaped cross-sectional shape, and
a connecting rod main body portion in which each end of the portion forming the connecting portion forms a large diameter end portion by curving the U-shaped back surface along approximately a quarter circumference;
[b) a bearing member that is provided with a pin hole that allows a pin attached to the piston to pass therethrough and is fitted and welded to the inside of the annular small diameter end, and tc>each parallel to the longitudinal direction of the connecting rod; and a pair of blocks welded to both sides of the large diameter end.

Functions and Effects When fixing a cap to a connecting rod configured as described above, align the through hole in the block with the through hole formed on the cap side, and then insert the bolt from the connecting rod side. Either screw the nut onto the tip of the bolt and tighten it, or form a female thread on the inner surface of the through hole of the block and insert the bolt from the cap side and tighten it. In other words, it can be connected to the cap in the same way as a connecting rod manufactured by forging, and by appropriately selecting the length of the block and the thickness of the connecting rod to be tightened, a bolt of sufficient length can be used. In addition to being able to screw a bolt into a female screw hole of sufficient length, the area around the through hole of the pro-tsuku is solid and has sufficient compression rigidity.
Sufficient elongation can be given to the bolt with the cap coupled to the connecting rod. Therefore, loosening of the bolt can be effectively prevented despite fluctuations in the load applied to the bolt and changes in temperature.

In addition, since the through-hole for bolt insertion or the female threaded hole for screwing the bolt is formed in the solid block, it is easy to form these through-holes and female threaded hole at a position close to the concave surface of the bearing. The moment applied to the large diameter end during engine operation is reduced, which is advantageous in terms of strength design.

Moreover, since the connecting rod main body is manufactured by pressing plate materials and welding, it is possible to fully enjoy the effect of weight reduction.

In addition, since the block is welded to the connecting rod body along a sufficiently long weld line, the force applied to the block is transmitted to the wide part of the connecting rod body and is efficiently received, allowing the connecting rod to This is also advantageous in terms of overall strength design. moreover,
Since the block that functions as the part to be tightened by the bolt is formed separately from the connecting rod body and fixed by welding, it is different from the case where the part to be tightened is formed by pressing plate material and welding. This simplifies the structure of the connecting rod, facilitates manufacturing, and reduces costs.

EXAMPLE Hereinafter, an example of the present invention will be described in detail based on the drawings.

In FIGS. 1 and 2, reference numeral 2 denotes a main body of a connecting rod according to an embodiment of the present invention.

This main body part 2 is formed by welding a longitudinal member having a U-shaped cross section, and the longitudinal member is curved at the center in the longitudinal direction with the back surface of the U-shape inward. a small-diameter end 4; a connecting portion 6 connected to the small-diameter end 4 and formed so that the back surfaces of the U-shape are welded together to form an H-shaped cross section; and a portion forming the connecting portion 6. Each vertically split large diameter end 8 has a U-shaped back surface that is approximately a quarter of the other.
The large diameter end portion 10 is curved along the circumference.

A bearing member 12 is fitted inside the small diameter end portion 4 . A pin hole 14 is formed in this shaft receiving member 12, and a piston pin 16 provided on a piston (not shown) is inserted into this pin hole 14 either directly or through a bearing metal as shown in FIG. It has become so. Furthermore, a synthetic resin body 17 reinforced with carbon fiber, glass fiber, etc. is filled between the flanges of the small diameter end portion 4 to increase the strength of the connecting rod.

Further, the large diameter end 10 has a semicircular bearing concave surface 18 formed by connecting the curved back surfaces of the longitudinally split large diameter ends 8, and also includes a semicircular bearing concave surface 19. When the connecting rod cap 20 is fixed to the connecting rod, the crank pin 23 is supported together with the bearing concave surface 19 of the connecting rod cap 20 via the semicircular bearing metal 22.

Further, a stepped portion 24 is formed on the opposite side of each vertically divided large diameter end portion 8 from the mutually welded sides, and a block 26 having a rectangular cross section is fixed to each of the stepped portions 24. ing. The block 26 has a through hole 28 extending in the longitudinal direction formed in its center, and one of the side walls surrounding the through hole 28 has approximately half cut out in the longitudinal direction to form a stepped portion 30. The stepped portion 30 is engaged with the stepped portion 24, and is fixed by welding in a position such that the through hole 28 is parallel to the longitudinal direction of the connecting rod. In this fixed state, the end face of the block 26 located on the large diameter end side of the main body portion 2 constitutes a mating face with which the connecting rod cap 20 is fitted together with the end face of the vertically split large diameter end portion 8. . Further, carbon fibers are provided between the flanges extending from each longitudinally split large diameter end portion 8 to the connecting portion 4.

A synthetic resin body 32 reinforced with glass fiber or the like is filled to increase the strength of the connecting rod.

Next, an example of a method for manufacturing the main body portion 2 configured as described above will be described.

First, as shown in FIG. 5, a plate piece 36 is punched out from a steel plate 34 using a press device (not shown).

This plate piece 36 has a length that is more than twice the total length of the main body portion 2, and its shape is determined in consideration of the drawing process, bending process, etc. in the subsequent process. In this embodiment, the central portion 4
It has a longitudinal shape in which the width dimension at 0 is narrower than that at both ends 42 .

Next, both ends 42 of the plate piece 36 are drawn using a drawing die 44 shown in FIG.

The drawing die 44 includes a die 46, a punch 48 that is driven toward and away from the die 46 in the vertical direction, and a wrinkle presser 50. A recess 52 is formed in the die 46 and has substantially the same shape as the U-shaped vertically divided large diameter end 8 in cross section constituting the large diameter end 10 .

As is clear from FIG. 1, the longitudinally split large diameter end portion 8 has a portion adjacent to the bearing concave surface 18 that is bent at a substantially right angle thereto, and a pair of bent portions are formed at both ends of the concave surface 18. Sections 54 and 56 are present.

Therefore, the shape of the recess 52 in the longitudinal direction is a hole shape whose bottom is a convex surface corresponding to the bearing concave surface 18, and the portion A corresponds to the bent portion 54.56.

The straight line connecting B is substantially parallel to the upper surface 58 of the die 46. Therefore, the inclination angle θ4. At the same time as θ2 is reduced, the depths of AfB and B portions are made the same, and the plate piece 36 is drawn in the most desirable state, so even if the plate piece 36 is made of high-tensile steel, the A Department,
The radius of curvature at the part B can be made extremely small, and the drawing depth can be made relatively thick. Also, the portions where both longitudinal ends of the recess 52 and the upper surface 58 are in contact are formed into gentle curved surfaces. , drawing processing is said to be easier.

Note that on the surface of the punch 48 facing the die 46, a convex portion 60 having a shape corresponding to the concave portion 52 and having a gap between the concave portion 52 and the thick bone of the plate piece 36 is formed. There is. Further, although FIG. 6 shows the right side portion of the drawing die 44, a recess 52 and a convex portion 60 are also provided symmetrically to the left side portion (not shown).

When the plate piece 36 is placed at a predetermined position on the upper surface 58 of the die 46, the shin holder 50 is lowered and the peripheral edge of the plate 36 is pressed between the upper surface 58 and the shin holder 50. Ru. Next, by lowering the punch 48, both ends 42 of the plate piece 36 are drawn at a predetermined distance apart, as shown in FIGS. 7 and 8.
It has a bottom wall portion 62 and a pair of side wall portions (flanges) 64 that are perpendicular to the bottom wall portion 62 and continuous to its side edges, and have approximately the same shape as the longitudinally split large diameter end portion 8. A recessed portion 66 having a U-shaped cross section is formed. Note that FIGS. 7 and 8 show the right half of the plate piece 36, and a recess 66 is also formed symmetrically in the left half (not shown). This also applies to the following steps.

Note that such a recessed portion 66 does not necessarily need to be formed by one-stage drawing. In other words, if the material of the plate piece 36 has high strength and rigidity, such as high-tensile steel, and has relatively little elongation, it may be drawn in multiple stages as necessary to gradually form a predetermined shape. All you have to do is mold it.

After forming the recessed portions 66 of a predetermined shape on both ends 42 of the plate piece 36 as described above, the excess portions of the outer periphery such as the wrinkle suppressing portions of both ends 42 are removed by cutting or machining. , as shown by the two-dot chain line in FIG. 8, the side wall portion 64 is made into a stepped shape by removing the excess portions of both ends 42.

As a result, the recessed portion 66 becomes a vertically split large diameter end portion 8 as shown in FIG. 9 and FIG.

Next, as shown in FIG. The bending process is performed using a bending die 68 that has been prepared.

The bending die 68 includes a die 70 and a punch 72 that is driven toward and away from the die 70 in the vertical direction. The die 70 is provided with a recess 74 in its longitudinal direction, that is, in the left-right direction in FIG. ing. The shape of the recess 74 in the longitudinal direction is almost the same as the shape obtained by dividing the main body 2 symmetrically vertically and developing the small diameter end 4 as the central part, and connects the connecting part 6 and the small diameter end. A pair of bent portions 76 between 4 and 4.
A straight line connecting the portions C corresponding to is substantially parallel to the upper surface 78 of the die 70. Further, the lower end 80 of the punch 72 has a gap between the recess 74 and the thick bone of the plate piece 36, and has a convex shape corresponding to the recess 74.

With both sides of the plate piece 36 near the center 40 supported on the upper surface 78 of the die 70, the plate piece 36 is placed in a predetermined position as shown by the two-dot chain line in FIG.
When the plate piece 36 is lowered, a bending process is performed in the vicinity of the center portion 40 of the plate piece 36. As a result, as shown in Fig. 12,
The vicinity of the center portion 40 is formed into a U-shape in cross section, consisting of a bottom wall portion 82 continuous to the bottom wall portion 62 and a side wall portion 84 continuous to the side wall portion 64, and is formed into a vertically split shape from the plate piece 36. Longitudinal member 8 formed symmetrically with large diameter end 8 on the outside
6 is formed.

Here, in the main body part 2 of this embodiment, a bearing member 12 is fitted into the small diameter end part 4 to support the piston pin 16, and the connection part 6 and the small diameter end part 4 are connected to each other. The radius of curvature of the bent portion 76 is much larger than that of the bent portion 54,56. Therefore, when forming this bent portion 76, although some drawing processing is involved, in particular, the drawing die 4
This eliminates the need for the wrinkle presser 50 as shown in 4.

In addition, in this bending process, it is possible to set the size of the side wall part 84 relatively large, but considering the strength, rigidity, etc. required for the bending process in the subsequent process or the small diameter end part 4. and its size is set as necessary and sufficient.

The elongated member 86 formed in this way has almost the same shape as the main body 2 divided vertically and expanded laterally, but the amount of bending elongation and the like due to the bending process in the subsequent process is taken into consideration. Although the longitudinal member 86 has an almost perfect shape when the above-mentioned bending process is completed, the shape and surface of the opening side edge of the side wall portion 84 are removed to improve its strength. Cutting as necessary, such as when securing.

The external shape is finished as appropriate by grinding, etc. Assuming this external finishing process, Figures 7, 8 and 9,
Part or all of the process of removing the outer periphery of the plate piece 36 described in FIG. 10 may become unnecessary.

Next, using a bending device 88 shown in FIGS. 13 and 14, the longitudinal member 86 is bent at its center.

The bending device 88 includes a base 92 having a horizontal support surface 90 that supports one of the vertically split large-diameter ends 8 of the longitudinal member 86, and a central axis disposed perpendicularly to the support surface 90. The rotating member 96 is rotatable around the bearing member 94, and the center jig 98 has an outer peripheral shape substantially similar to that of the bearing member 12 and is fitted onto the center shaft 94. A stepped portion 100 is formed on the base 92 and is configured to position one vertically split large diameter end portion 8 of the longitudinal member 86.
The positioned longitudinal member 86 is fixed by the crutch metal fitting 102 and the bolt 104. Further, the central shaft 94 is guided by the frame 106 and reciprocated in its axial direction, and the center jig 98 is also reciprocated in its axial direction.

The rotating member 96 has a longitudinal shape, and a pair of parallel protrusions 110 and 112 are provided at one end by forming a notch 108 in the longitudinal direction. The dimension of the notch 108 in the width direction is the same as the width dimension of the longitudinal member 86, that is, the dimension between the outer surfaces of the both side wall portions 84. At the end of one protrusion 110, the central axis 9
An insertion hole 114 is formed into which the holder 4 is slidably inserted. The other protrusion 112 has a smaller protrusion dimension than the protrusion 110, and when the center shaft 94 is inserted into the insertion hole 114, the tip of the protrusion 112 is in contact with the outer peripheral surface of the center jig 98. The side protrusion 1
An insertion hole 116 is formed in 10 and 112 to pass through them in the vertical direction, and a pair of plates 118 fixed to the opening of the insertion hole 116 allow the rotation shaft 1
20 is rotatably supported within the insertion hole 116.

A roller 122 is fitted and fixed to an intermediate portion of the rotating shaft 120, and the diameter of the roller 122 is such that the diameter of the roller 122 is equal to the diameter of the bottom wall portion 82 of the longitudinal member 86 between the outer circumferential surface of the roller 122 and the outer circumferential surface of the center jig 98. The dimensions are such that a gap of approximately the same size as the wall thickness is formed. Further, the width (thickness) dimension of the roller 122 in the axial direction is approximately the same as the dimension between the inner circumferential surfaces of both side walls 84 of the longitudinal member 86, and the width (thickness) of the roller 122 is approximately the same as the dimension between the inner peripheral surfaces of the both side walls 84 of the longitudinal member 86, and
A gap approximately the same size as the wall thickness of the side wall portion 84 is formed between the side wall portion 84 and 112, respectively.

At the end of the rotating member 96 opposite to the side where the insertion hole 114 is formed, there is a notch for engaging with a drive pin 124 that is connected to a drive device (not shown) and driven along one circumference. 126 is formed. And the rotating member 96
When the drive pin 124 is engaged with the notch 126, the drive pin 124 is rotated about the central axis 94 in the direction of the arrow X shown in FIG.

In the bending device 88 configured as described above, first, the longitudinal One vertically split large diameter end 8 of the member 86 is positioned and fixed at a predetermined position on the support surface 90 as described above. Next, the rotating member 96 is set at a predetermined location shown by the solid line in FIG. The tool 98 is raised until its upper edge abuts the protrusion 110. After adjusting the position of the rotating member 96 so that the insertion hole 114 of the rotating member 96 is aligned with the center jig 98, the center shaft 94 is lowered and fitted into the insertion hole 114 and the center jig 98. FIG. 13 and FIG. 14 show this state.

From this state, when the rotating member 96 is rotationally driven in the direction of arrow X to the position shown by the two-dot chain line in FIG. 4 is bent along the outer peripheral surface of the center jig 98 while being sandwiched between the roller 122 and the center jig 98, and the left and right bottom wall portions 82 and 62 are butted against each other. Ru. 1st
The two-dot chain lines in FIGS. 3 and 14 show this state, and a bent semi-finished product 128 is thereby formed.

Here, the longitudinal member 86 has its bottom wall portion 82 inside,
In other words, the longitudinal member 86 is bent with its U-shaped cross-sectional shape facing inward, and the open side of the side wall portion 84 faces outward, resulting in so-called stretch flange forming, which is easier to process than shrink flange forming. . Further, both side wall portions 84 are connected to the side surfaces of the roller 122 and the protrusions 110 and 11.
Since the longitudinal member 86 is bent while being sandwiched between the two, there is almost no possibility that the side wall portion 84 will be wrinkled or distorted. Furthermore, the center shaft 94 that positions the center of rotation of the rotating member 96 has both upper and lower ends supported by the frame 106 and the center jig 98, respectively, and has a both-end support structure, so its strength and rigidity are high and the rotation Even if a large load is applied to the member 96, it can sufficiently withstand it.

Thereafter, after disengaging the drive pin 124 and the notch 126, the center shaft 94 and center jig 98 are driven to the original raised position and lowered position, respectively, the rotating member 96 is removed, and the bolt 104 is loosened. The bent semi-finished product 128 is removed from the base 92.

Next, using a shaping device 130 shown in FIG. 15, the shape of the bent semi-finished product 128 is corrected and temporarily welded.

The shaping device 130 includes a table 132 for positioning the vertically split large-diameter end 8 of the bent semi-finished product 128, a jig 136 for positioning the bent portion 134 bent in the previous process, and the table 132. and a pair of shaping press tools 138 and 140 that press the bent semi-finished product 128 positioned by the jig 136 from left and right with a high load.

The stand 132 is provided with a protrusion 142 having a semicircular cross section and having the same outer shape as the semicircular shape of the bearing concave surface 18 of the main body part 2 in order to position the vertically divided large diameter end parts 8 respectively. There is. The jig 136 has the same external shape as the bearing member 12, and has the same bent portion 1 of the bent semi-finished product 128.
34 is fitted into the jig 136.

Further, the shaping press tools 138 and 140 are
32 and the bent semi-finished product 128 positioned by the jig 136 from both sides, the direction is symmetrically inclined so that it advances from the bent part 134 side to the longitudinally split large diameter end part 8 side, that is, the 15th They are driven toward and away from each other along the directions indicated by arrows Y and Z in the figure. - The wall thicknesses of both shaping press tools 138 and 140 are approximately the same as the width dimension between the inner surfaces of both side wall portions 64, 84 of the bent semi-finished product 128, and the shape of their abutting portions is as follows. , is the shape that the bottom wall portion 62°82 of the finished product body 2 should have. In addition, these shaping press tools 13
8 and 140 have insertion holes 14 from the left and right directions, respectively.
6,148 are formed concentrically, and their insertion holes 1
46, 148 contains electrodes 150, 15 for spot welding.
2 is disposed so as to be movable in the axial direction.

When shaping the bent semi-finished product 128, first the bent semi-finished product 128 is held on the stand 13 with both shaping press tools 138 and 140 held at positions separated from each other.
Position on 2. In this state, both shaping press tools 13
8 and 140 in the direction of approaching each other, the main body part 2
The bent semi-finished product 128 is a part corresponding to the connecting part 6 of , and is separated by springback action in a free state.
The bottom wall portions 62 and 82 of the two are pressed together and brought into close contact with each other.

As a result, in particular, the bent portion 76 (see FIG. 1) between the connecting portion 6 and the small diameter end portion 4 can be clearly formed, and the bent semi-finished product 128 can be formed at the butt portion of the two shaping press tools 138° 140. In other words, it is shaped into the shape that the main body part 2 as a finished product should have, and is maintained in that state.

After that, the insertion holes 14 of both shaping press tools 138 and 140 are
The electrodes 150 and 152 in the electrodes 6 and 148 are advanced toward each other to spot weld a portion of the bottom wall portion 62 or 82 of the bent semi-finished product 128 that is in close contact with each other.

As a result, springback of the bent semi-finished product 128 is prevented, and the shape shaped by the shaping device 130 is maintained as it is. FIG. 16 shows the bent semi-finished product 128 thus formed, and the reference numeral 153 shown in FIG. 15 indicates the above-mentioned temporarily welded portion.

Next, in the concave portion 134 of the bent semi-finished product 128, there are two triangular projections made of an iron-based material shown in FIG. The bearing member 12 having a protruding expansion and flexibility is fitted, and partial welding shown at 156 in FIG. 1 is performed from both the front and back sides of the bearing member 12 to fix the two. In addition, spot welding indicated by reference numeral 158 is further performed at a number of locations of the portion corresponding to the connecting portion 6 of the main body portion 2 which has been subjected to the spot welding, and partial welding indicated by reference numeral 160 is also performed from both the front and back sides. , the abutting portions of the bent semi-finished products 128 are firmly fixed. Furthermore, there is a notch 154 in the portion where the bent portions 56 of the longitudinally split large diameter end portions 8 are butted together, and this portion is formed by continuous overlay welding shown at 162 and then cutting. A bearing concave surface 18 is finished with high precision. According to this embodiment, since the bent portion 56 is formed with an extremely small radius of curvature, there is an advantage that the overlay welding described above can be performed easily and with less thermal strain. Note that it is also possible to process the surfaces that come into close contact with the block 26, including the stepped portion 24 shown in FIG. 1, at this stage.

Once the main body portion 2 is formed as described above, the block 26 is fixed to the vertically divided large diameter end portion 8. The block 26 is made of an iron-based material, and a through hole 28 is formed in advance, the stepped portion 24 and the stepped portion 30 are engaged, and beam welding is performed between the contact surfaces to form the welded portion 164. form. Then, if necessary, the end face of the block 26 to be mated with the connecting rod cap 20 is finished at the same time as the mating face of the longitudinally split large diameter end portion 8.

After fixing the block 26, the small diameter end 4 and the large diameter end 10
A synthetic resin body 17.32 is stuffed between the side walls to reinforce it.

As this reinforcing step, lamination molding using epoxy resin such as glass cloth or carbon fiber mantle is suitable.

Note that the drawing die 449, bending die 68, and bending device 8 used in the connecting rod manufacturing process detailed above
8. All of the shaping devices 130 perform press working under high pressure, and therefore, the main body portion 2 processed by these devices has little springback and high rigidity.

The method for manufacturing the connecting rod has been described above in detail. Next, the method for attaching the connecting rod to the piston pin 16 and the crank pin 23 will be described based on FIGS. 3 and 4.

→ First, insert the piston pin 16 into the pin hole 14 of the bearing member 12.
is inserted directly or through a bearing metal (not shown), and in this state, a piston (not shown) is placed in the cylinder.

Next, the large diameter end 10 of the main body 2 protruding from the end of the cylinder is placed over the crank pin 23 via the bearing metal 22, and the connecting rod cap 20 is placed on the crank pin 23 of the main body 2. Bearing metal 22 from the opposite side
straddle the body part 2 and the block 2, and
Align it with the end face of 6. The connecting rod cap 20 is made by forging, and when fitted to the main body 2 as described above, the through holes 1 formed at both ends of the connecting rod cap 20 are formed by forging.
70 and the through hole 28 formed in the block 26 are aligned, and the bolt 1 is inserted into the through hole 28 from the block 26 side.
72 is inserted, and the screw 7) 174 is screwed into the threaded portion protruding from the through hole 170 of the bolt 172, and then tightened, the connecting rod and the connecting rod cap 20 will be connected with sufficient bonding strength. .

As described above, the connecting rod of this embodiment is connected to the cap 20 by the screwing of the bolt 172 and the nut 174. Since the peripheral portion of the bolt 172 is solid and has sufficient compression rigidity, sufficient elongation can be expected when the bolt 172 is tightened, and loosening of the bolt 172 can be effectively prevented.

In addition, since the block 26 is fixed to the main body 2 with a welded portion 164 of sufficient length, the force applied from the bolt 172 is transferred from the block 26 to the side wall (flange) of the main body 2.
It is transmitted to a wide area such as 64.84 and is efficiently received. That is, these side wall portions 64, 84 effectively function as reinforcing flanges.

Furthermore, in this embodiment, the main body 2 is made of a steel plate, and the bearing member 12 and the block 26 are made of iron-based materials, so welding is easy and the connecting rod can be made lightweight and inexpensive. can be manufactured.

Furthermore, since the block 26 into which the bolt 172 is inserted is formed separately from the main body 2 of the connecting rod and is fixed to the main body 2, the box-shaped bolt receiver forms a part in the main body 2. The shape of the main body part 2 does not become complicated as in the case where the main body part 2 is made, and it can be easily manufactured.

In addition, according to the drawing process 1 bending process described above, it is possible to process high-strength materials such as high-strength steel, which expands the range of material selection and also reduces weight from the material standpoint. You can also try it out.

In addition, devices used for manufacturing the main body portion 2, namely, a drawing die 441, a bending die 681, a bending device 88, and a shaping device 13.
0 and the welding device are both excellent in mass production, and can be automated in combination with a control device.

Therefore, in conjunction with the reduction in material costs due to the expansion of the selection range of materials mentioned above, the main body portion 2 can be manufactured at low cost. In particular, since inexpensive steel plates can be used, material costs can be significantly reduced compared to forged products.

Furthermore, since the steel plate 34 is manufactured by applying plastic working, the surface quality of the product is maintained better than that of forged products, and the occurrence of defective products due to surface defects is greatly suppressed, improving reliability. .

Note that it is also possible to perform surface hardening treatment or the like during the manufacturing process, which has the advantage of further improving the strength and other properties of the main body portion 2.

Although one embodiment of the present invention has been described above in detail based on the drawings, the present invention can be implemented in other embodiments.

For example, in the embodiment described above, the through hole 28 of the block 26
Although the pin holes 14 of the bearing member 12 are formed before the block 26 and the bearing member 12 are fixed to the main body 2, they may be formed after these are fixed to the main body 2. , this through hole may have a female thread formed on its inner peripheral surface.

Furthermore, although the connecting rod cap 20 was made by forging, it can also be formed by pressing a plate material and have a U-shaped cross section, in the same way as the main body part 2. Sufficient strength can be obtained by fixing a block having the same structure as the block 26 and inserting bolts 172 into the block.

Moreover, the main body part 2. Bearing member 12. Block 26 is a steel plate,
Unable to get excited about iron-based materials, we started using aluminum alloys.
Any material that can be welded can be used.

Furthermore, in the embodiment described above, the elongated member 86 is connected to the drawing die 44.
The shape is formed in two steps: drawing by the bending die 68 and bending by the bending die 68.
Depending on the conditions such as the material of
may be formed. Furthermore, the above-mentioned Japanese Patent Application Publication No. 57-1880
It is also possible to form the main body by a method mainly based on bending as described in No. 9.

Furthermore, in the embodiments described above, the water droplet-shaped bearing member 12 is fitted into the small diameter end portion 4 of the main body portion 2, and the radius of curvature of the bent portion 76 of the four small diameter end portions is made relatively large. Instead of the member 120, a ring-shaped bearing or the like may be fitted.

Furthermore, the drawing die 442 and the bending die 68 in the above-described embodiment
1 bending device 88. Devices such as the shaping device 130 are merely examples of devices that can suitably implement the present invention, and other devices and processing means can also be used.

In addition, various modifications may be made to the present invention based on the knowledge of those skilled in the art, although it is not necessary to exemplify them individually.

It can be implemented in a modified form.

[Brief explanation of drawings]

FIG. 1 is a front view showing a connecting rod according to an embodiment of the present invention. FIG. 2 is a sectional view taken along the line ■-■ in FIG. 1. FIGS. 3 and 4 are diagrams showing a state in which the connecting rod is disposed between the piston pin and the crank pin, and are a partially cutaway front view and a side view, respectively. 5 to 17 are views explaining the process of manufacturing the above-mentioned connecting rod, and FIG. 5 is a view showing the process of punching out a plate piece from a flat material. FIG. 6 is a longitudinal cross-sectional view showing the main part of the drawing die that applies the drawing process to the plate piece, and FIGS. 7 and 8 are a front view and a plan view showing the right half of the plate piece that has been subjected to the drawing process. It is a diagram. FIGS. 9 and 10 are a front view and a plan view showing the right half of the plate piece from which the longitudinally divided large diameter end portion was formed by removing the excess portion after the drawing process described above. FIG. 11 is a longitudinal cross-sectional view showing the main part of a bending die for bending the plate piece with the above-mentioned end formed, and FIG. 12 is a front view showing the right half of the longitudinal member formed by the bending process. It is a diagram. 13th
Figures 1 and 14 are views for explaining the main parts of a bending device for bending the longitudinal member, and are a partially cutaway plan view and a longitudinal cross-sectional view. FIG. 15 is a plan view showing the main parts of a shaping device that shapes and temporarily welds the bent semi-finished product formed by the above bending process. Figure 16 shows plastic surgery. FIG. 17 is a perspective view of a temporarily welded bent semi-finished product, and FIG. 17 is a perspective view of a bearing member fitted into the bent portion of the bent semi-finished product.

Claims (2)

[Claims] (1) A connecting rod that connects a piston and a crankshaft of a reciprocating engine, which is made of a pressed plate material and has a U-shaped cross section, with the longitudinal center portion of the longitudinal member being U-shaped. By curving the back side of the letter inward, an annular small-diameter end is formed, and the part adjacent to the center has an H-shaped cross-sectional shape by welding the back sides of the U-shape to each other. forming a connecting portion, and each end of the portion forming the connecting portion forms a large diameter end by curving the back surface of the U-shape along approximately one-fourth of the circumference. a connecting rod body; a bearing member having a pin hole that allows a pin attached to the piston to pass therethrough; and a bearing member that is fitted and welded to the inside of the annular small diameter end; A connecting rod comprising a pair of blocks having parallel through holes and welded to both sides of the large diameter end. (2) The connecting rod according to claim 1, wherein the pressed connecting rod main body is reinforced with fiber-reinforced synthetic resin.