JP2003322138A - Connecting rod and connecting rod with bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a connecting rod capable of deceasing weight and size, and a connecting rod with a bearing. <P>SOLUTION: The connecting rod 1 has a large end 3 and a small end 4 each having a generally circular outer diameter surface on both ends of a rod 2, and through holes 5 are formed in the large end 4 and the small end 4. Centers O1 of the outer diameter surfaces of the large end 3 and the small end 4 are decentered to the rod 2 side relative to centers O2 of the through holes 5. The outer peripheral surfaces of the large end 3 and the small end 4, and side surfaces at both ends of the rod 2 are smoothly continued on a concave curved surface R having an arc-shaped cross-section. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a connecting rod used in a power transmission portion of a general-purpose engine or a motorcycle engine, and a connecting rod with a bearing thereof.

[0002]

2. Description of the Related Art An example of a conventional connecting rod is shown in FIG. The connecting rod 51 has a large end portion 53 and a small end portion 54, each of which has a substantially circular outer diameter surface, at both ends of a rod portion 52, and a through hole 55 is provided in the large end portion 53 and the small end portion 54. It is a thing. The centers of the outer diameter surfaces of the large end portion 53 and the small end portion 54 are aligned with the center of the through hole 55, and therefore, at the large end portion 53 and the small end portion 54,
The radial thickness around the through hole 55 is uniform.
The connecting rod 51 is manufactured by forging, sintering, or constrained pressure molding using a steel bar material, a plate material, or the like. In addition, recently, it is also manufactured by pressing. Conventionally, a connecting rod of a general-purpose engine has been required to be lightweight for the purpose of reducing vibration, and an aluminum material or the like is also used.

[0003]

However, since the conventional connecting rod 51 has a constant radial wall thickness around the through hole 55 in the large end portion 53 and the small end portion 54, the radial wall thickness is reduced in order to reduce the weight. When the thickness is reduced, when the tensile load is generated, the rod end portions 53a and 54 of the large end portion 53 and the small end portion 54 are formed.
A large stress acts on a, resulting in insufficient strength. Further, in the rod portion vicinity portions 53a and 54a, since the outer shape is abruptly changed with respect to the rod portion 52, stress concentration may occur, resulting in insufficient strength.

An object of the present invention is to provide a connecting rod which can be made lightweight and can be made compact, and a connecting rod with a bearing.

[0005]

A connecting rod according to the present invention has a large end portion and a small end portion each having a substantially circular outer diameter surface at both ends of a rod portion, and a through hole is formed in each of the large end portion and the small end portion. In the connecting rod provided with, the center of the outer diameter surface at the large end portion and the center of the small end portion is eccentric with respect to the center of the through hole. The eccentric direction is a direction in which the centers of the outer diameter surfaces of the large end portion and the small end portion are biased toward the rod portion side with respect to the center of the through hole. According to this configuration, since the center positions of the through hole and the outer diameter surface at the large end portion and the small end portion are eccentric to the rod portion side, the large end portion and the small end portion are in the vicinity of the rod portion where a large stress acts. The radial thickness of the portion is large, and the radial thickness of the portion where the acting stress is small becomes thin. Therefore, the material can be efficiently arranged in a portion requiring strength, and the weight can be reduced while securing the strength. Also, since the centers of the outer diameter surfaces of the large end and the small end are eccentric to the rod side, even if the dimensions between the through holes of the large end and the small end are the same, the entire connecting rod is eccentric. The length is shortened. Therefore, a compact design is possible.

In the present invention, the outer diameter surfaces of the large end portion and the small end portion and the side surfaces on both sides at both ends of the rod portion each have a connecting rod outer peripheral surface which is a smoothly curved continuous concave surface having an arcuate cross section. Good as a thing. When the concave curved surface is continuously formed in this manner, the outer shape smoothly changes between the rod portion and the large end portion and the small end portion, so that stress concentration is relieved and strength is further improved.

In these inventions, the connecting rod is formed of one steel plate, the through hole is a punched surface, has a shear surface and a fracture surface, and the fracture surface on the inner peripheral surface of the through hole occupies. The ratio may be 20% or less. In the case of such a configuration, since the ratio of the fracture surface on the inner peripheral surface of the through hole is 20% or less, the machined surface is clean and accurate even though it is a punched machined surface. Therefore, the bearing can be fitted into the through hole by press fitting or the like without performing post-processing. 2 fracture surfaces
The punching process of 0% or less can be realized by, for example, a fine blanking press (also called precision punching). In this way, since it can be formed by punching and post processing such as grinding and polishing is not required, it is easy to manufacture,
Man-hours and costs can be reduced. It should be noted that the smaller the proportion of the fracture surface is, the better, but it does not become zero by punching, and the fracture surface remains.

In this way, when the through hole has a punched surface in which the fracture surface occupies 20% or less, the outer peripheral surface of the connecting rod may be a punched surface having a shear surface and a fracture surface. In that case, it is preferable that the ratio of the fracture surface on the outer peripheral surface of the connecting rod is 20% or less. Thus, when the outer peripheral surface of the connecting rod is used as the punched surface, both the outer peripheral shape of the connecting rod and the through hole can be processed by the punching, and the connecting rod can be punched at the same time, which further improves the productivity. Further, when the ratio of the fracture surface to the outer peripheral surface of the connecting rod is 20% or less, the shape of the outer peripheral surface of the connecting rod is beautiful and the quality of the connecting rod is improved. When the connecting rod is punched as described above, the rod portion may have a recess or a hole. If the rod has a recess or hole,
Can be lightened. This recess or hole can also be processed by a fine blanking press.

In the connecting rods of these inventions, divided connecting rod parts each having a large end portion, a small end portion, and a rod portion are laminated, and an annular component is formed at the large end portion and the small end portion in the laminated body of the divided connecting rod components. Alternatively, the divided connecting rod parts may be integrated by press-fitting. In addition, each divided connecting rod component is, for example, a flat plate-shaped component, and is preferably a stamped product of a material plate material. Each divided connecting rod part is, for example, a part having the same shape. In the case of this configuration, since the divided connecting rod parts are laminated and the annular parts are press-fitted and integrated, even if the inner surface of the large end or the small end of each divided connecting rod part is inclined,
It is possible to eliminate inclination of the inner diameter surfaces of the large end portion and the small end portion of the laminated body, and integrate the annular parts without inclination. For example, when the individual divided connecting rod parts are ordinary punched products, the inner surface of the large end or the small end is tilted due to the fracture surface, but since the plate thickness becomes thin due to the division, The step difference between the shear plane and the fracture surface is reduced, and the fracture surfaces are dispersed and arranged by stacking. For this reason,
The inclination of the inner diameter surface at the large end and the small end of the laminated body as a whole can be avoided. Further, even if there are irregularities on the inner diameter surfaces of the large end portion and the small end portion in the fracture surface of the press work, the annular fitting is press-fitted to avoid the influence on the bearing fitting surface and the bearing surface. Therefore, a press punched product can be adopted for each divided connecting rod part, and a post-process such as grinding and polishing of the large end portion and the small end portion thereof becomes unnecessary. Also, no special press die or press machine such as a fine blanking press is required. Therefore, the connecting rod can be manufactured easily and inexpensively.

Further, the connecting rod of the present invention comprises a connecting rod body of a cast aluminum product, and a cylindrical member provided at a large end portion and / or a small end portion of the connecting rod body in a penetrating state. The cylindrical member may have an uneven portion for meshing with the connecting rod body on the outer diameter surface, and may be fixed to the connecting rod body by casting the connecting rod body. The aluminum cast product is meant to include a cast product of an alloy containing aluminum as a main component. The connecting rod of this configuration is
It is used in combination with a rolling bearing by press-fitting the rolling bearing into the inner diameter surface of the cylindrical member or by utilizing the inner diameter surface of the cylindrical member as the raceway surface of the rolling bearing. Since the cylindrical member has a concavo-convex portion for meshing on the outer diameter surface, the conrod body is arranged and cast in the mold together when the connecting rod body is cast, so that the conrod body follows the outer diameter surface of the cylindrical member to form the concavo-convex portion. It is cast in a state where it meshes with and is fixed to the cylindrical member. In this way, since the cylindrical member meshes with the connecting rod body at the uneven portion of the outer diameter surface and is prevented from coming off, even if there is a difference in thermal expansion coefficient between the cylindrical member and the connecting rod body, it does not come off when the temperature rises, The material of the cylindrical member can be freely selected. Therefore, even if the cylindrical member is made of steel or the like and the rolling bearing is press-fitted and attached, loosening of the press-fitting does not occur when the temperature rises, and it is possible to combine the aluminum connecting rod body and the rolling bearing. Further, if the cylindrical member is made of steel, the rigidity and surface hardness required for the raceway surface of the rolling bearing can be secured, and this also makes it possible to use it in combination with the rolling bearing. Also,
Since the connecting rod body is made of aluminum, the connecting rod can be made significantly lighter than the one made entirely of steel, and the responsiveness of the engine is improved. Since the cylindrical member is fixed to the connecting rod main body by casting the connecting rod main body, a separate fixing operation is not required, and the productivity of the connecting rod is good. The concavo-convex portion on the outer diameter surface of the cylindrical member preferably has a shape capable of both functions of preventing the cylindrical member from coming off and preventing rotation. For example, the concavo-convex portion may be an inclined groove or an inclined ridge that is inclined with respect to the axial direction of the cylindrical member and extends in the circumferential direction of the cylindrical member.

The connecting rod with a bearing of the present invention is the connecting rod of any one of the above in the present invention,
Rolling bearings are fitted in the through holes of the large end portion and the small end portion, respectively. With this configuration, the connecting rod is lightened as described above, so that the bearing-equipped connecting rod can be made lighter and more compact.

In this connecting rod with bearing, the rolling bearing has an outer ring and a plurality of rollers rolling along the rolling surface of the outer ring, and the length of the roller is the same as that in the through hole penetrating direction of the connecting rod. It may be longer than the width. In the case of this configuration, since the length of the roller is made longer than the connecting rod width, even if the connecting rod width is narrowed to reduce the weight of the connecting rod, the roller length is secured and the life of the bearing can be extended.

[0013]

1 is a block diagram of a first embodiment of the present invention.
~ It demonstrates together with FIG. As shown in FIG. 2, the connecting rod 10 with bearings has bearings 6 fitted in through holes 5 of the large end portion 3 and the small end portion 4 of the connecting rod 1, respectively. As shown in FIG. 1, the connecting rod 1 has a large end portion 3 and a small end portion 4 each having a substantially circular outer diameter surface at both ends of a rod portion 2, and penetrates the large end portion 3 and the small end portion 4. A hole 5 is provided. The center O1 of the outer diameter surface at the large end 3 and the small end 4 is the center O2 of the through hole 5 as shown in FIG.
On the other hand, the rod portion 2 side is eccentric by a predetermined amount Δd1 or Δd2. In the drawing, the center O1 of the outer diameter surface of the large end 3 and the small end 4 is the center O2 of the through hole 4.
The case of the conventional example which is matched with is shown by a broken line. The outer peripheral surface of the connecting rod 1 has a shape in which the outer peripheral surfaces of the large end portion 3 and the small end portion 4 and the side surfaces on both sides at both ends of the rod portion 2 are smoothly continuous with a concave curved surface R having an arcuate cross section. There is. The material of the connecting rod 1 is made of a metal material such as a steel material or an alloy, and may be a machined product, a pressed product, a cast product, a forged product, a sintered product, or the like obtained by any processing method. Further, the connecting rod 1 may be one in which a plurality of components are combined and integrated.

As shown in FIG. 2, the bearing 6 has an outer ring 7 and a plurality of rollers 8 rolling along a rolling surface consisting of the inner diameter surface of the outer ring 7, and each roller 8 is a ring-shaped cage. It is held at 9. The roller 8 and the cage 9 constitute a roller with a cage that is an assembly part of each other, and the roller with a cage can be inserted into the outer ring 7. Outer ring 7
Is a right cylinder.

The length B of the roller 8 is longer than the width A of the through hole 5 of the connecting rod 1 in the penetrating direction. Connecting rod 1
The width of the large end portion 3 and the small end portion 4 is set to the above width A, and the width of the portion of the rod portion 2 is narrower than the width A.
The width of the outer ring 7 of the bearing 6 is formed larger than the length B of the roller 8. The length B of the roller 8 referred to here is the total length of the roller 8, but the effective length of the roller 8, that is, the length of the portion where the outer peripheral surface is cylindrical is the connecting rod width A. It is preferable to be longer than the above. The effective length of the roller 8 is a length excluding the length of the chamfered portion, if the end portion of the roller 8 has a chamfered portion. Therefore, the roller effective length matches the effective width of the rolling surface when the rolling surface of the outer ring 7 is considered to be a geometrically cylindrical surface.

The bearing 6 is attached to the connecting rod 1 by press-fitting the outer ring 7 into the through hole 5 of the connecting rod 1. Due to this press-fitting, the rolling surface of the outer ring 7 has a larger inner diameter toward the opening side. Has become. Minimum inner diameter of rolling surface D0
(Fig. 4) and the diameter difference ΔD between the rolling surface inner diameter DB at the end of the roller 8 when the roller 8 is at the neutral position in the axial direction of the outer ring.
Is less than or equal to a predetermined value. This predetermined value is the cylindricity required for the rolling surface of the outer ring 7, and in numerical terms, the diameter difference Δ
D is 20 μm or less.

According to this structure, the center O1 of the outer diameter surface of the large end portion 3 and the small end portion 4 of the connecting rod 1 is formed through the through hole 5.
Since it is eccentric to the rod portion 2 side with respect to the center O2 of the rod portion, the radial thicknesses of the rod portion proximate portions 3a and 4a (through holes The thickness between the inner surface and the outer diameter surface of 5 is thick, and the radial thicknesses of the end side portions 3b and 4b, which are locations where the acting stress is small, are thin. Therefore, the material can be efficiently arranged in a portion requiring strength, and the weight can be reduced while securing the strength. This weight reduction leads to improved engine responsiveness. Further, since the center O1 of the outer diameter surfaces of the large end portion 3 and the small end portion 4 is eccentric to the rod portion 2 side, even if the dimensions of the through holes of the large end portion 3 and the small end portion 4 are the same, The entire length of the connecting rod 1 is shortened by that amount. Therefore, a compact design is possible. In this way, compared to the conventional product, the maximum stress generated under the action of tensile stress is the same,
The overall length is shortened and the weight can be reduced.

Further, in this connecting rod with bearing 10,
Since the length B of the roller 8 is made longer than the connecting rod width A,
While the connecting rod width A is narrowed to reduce the weight of the connecting rod 1, the roller length B can be secured and the life of the bearing can be extended.

The relationship between the bearing life and the length B will be described.
The bearing life is expressed by the following equation (1). L = [10 ⁶ / (60 × n)] × (Cr / Fr) ^10/3 (1) where Cr: Dynamic load rating Fr: Radial load n: Rotational speed L: Life time

Further, Cr in the equation (1) is represented by the following equation (2). Cr = fc (i cos α) ^0.78 Z ^2/3 Da ^1.07 la ^0.78 (2) where fc: Coefficient determined by bearing type and material i: Number of rows in which rollers are effectively operating α: Contact angle Z: Number of rollers per row Da: Roller diameter la: Roller contact length Depending on the roller contact length la, the life is improved. The contact length la of the roller is the above-mentioned effective roller length, assuming that the outer ring rolling surface is a geometrically cylindrical surface. When the roller length B is increased, the contact length la of the roller is also increased, and therefore the bearing life is improved.

In this embodiment, since the roller length B is made longer than the connecting rod width A, the bearing life can be improved while the weight is reduced as described above, but the roller length B is smaller than the connecting rod width A. If the roller bearing 6 is too long, when the roller bearing 6 is press-fitted into the through hole 5 of the connecting rod 1, the outer ring 7 is deformed such that the inner diameter of the rolling surface becomes larger toward the opening side, as exaggeratedly shown in FIG. In this case, if the inner diameter D _B (FIG. 4) of the rolling contact surface at the position of the roller end portion has a diameter difference ΔD larger than 20 μm with respect to the minimum rolling contact surface diameter D ₀ , the rolling contact surface is Even if the roller 8 is no longer supported at the position, and the roller length B is lengthened, the roller contact length la cannot actually be made sufficiently long. Therefore, the diameter difference ΔD is set to 2
It is specified to be 0 μm or less. This value of 20 μm or less usually indicates that the cylindricity is 20 μm as the rolling surface accuracy of the bearing.
The following values are required, so the value was set to ensure the cylindricity. Since the diameter difference ΔD is defined in this way, a long service life is ensured even though the inner diameter on the opening side of the rolling surface of the outer ring 7 is large as described above. Since the inner diameter of the rolling surface of the outer ring 7 is larger toward the opening side, a large load is not applied to the end of the roller 8 (so-called edge load), and the rotational torque is abnormally large. It will never happen.

In order to suppress the diameter difference ΔD to 20 μm or less, it is effective to use a highly rigid outer ring 7. That is, the outer ring 7 having a rigidity high enough to suppress the diameter difference ΔD to 20 μm or less is used. As the outer ring 7 having such rigidity, for example, a machined type outer ring having a right cylindrical shape and having a relatively large wall thickness.
The thickness of the outer ring 7 is set according to the interference with the through hole 5 of the connecting rod 1. The material of the outer ring 7 may be bearing steel or low carbon steel. The cage 9 may be made of any material, and may be any of press, welded, and machined cages. The retainer 9 may be surface-treated to prevent seizure. The roller 8 may be of a type that is detached from the cage 9 in the state where the shaft is not incorporated, or may be a type that is not detached.

In the above embodiment, the roller length B of each of the bearings 6 at the large end 3 and the small end 4 is longer than the connecting rod width A. The roller length B may be longer than the connecting rod width A for only one of the bearings 6. Further, the diameter difference ΔD between the rolling surface inner diameter D _B and the minimum diameter D ₀ at the roller end is 20 μm.
The value of m or less may be set only for the bearing 6 on either one of the large end portion 3 and the small end portion 4.

FIG. 6 shows another embodiment of the present invention.
In this embodiment, in the connecting rod with bearing 10 according to the first embodiment (FIGS. 1 to 4), instead of using the bearing 6 having the carved-out type outer ring 7, a bearing 6A having a shell-type outer ring 7A is used. Used. The shell type outer ring 7A is made of a press-formed product of steel plate,
It has a collar 7Aa on both sides. The shell type bearing 6A is also fixed by press fitting into the through holes 5 of the large end portion 3 and the small end portion 4 of the connecting rod 1. Other configurations in this embodiment are the same as those in the first embodiment. Even when the shell-type outer ring 7A is used, the minimum inner diameter of the rolling contact surface and the roller 8 can be obtained by appropriately controlling the press-fitting interference.
The diameter difference from the inner diameter of the rolling surface at the end of the can be 20 μm or less.

7 and 8 show a connecting rod 1A according to still another embodiment of the present invention. This connecting rod 1
In A, the rod portion 2 is provided with a recess 11 and a hole 12. Further, the connecting rod 1A is formed by punching from one flat plate-shaped steel plate, and the outer peripheral surface of the connecting rod 1A and the through holes 5 on both sides are punched surfaces. The recesses 11 and the holes 12 are also pressed at the time of punching. The punching process is performed by a fine blanking press, for example. The fine blanking press will be described in detail in the embodiment shown in FIG. 10 described later. This connecting rod 1A is used in place of the connecting rod 1 in the first embodiment.
As in the first embodiment, the center O1 of the outer diameter surface of the large end portion 3 and the small end portion 4 is eccentric to the rod portion 2 side with respect to the center O2 of the through hole 5. In addition, the outer peripheral surfaces of the large end portion 3 and the small end portion 4 and the side surfaces on both sides at both ends of the rod portion 2 are smoothly continuous with each other by the concave curved surface R having an arcuate cross section. Is the same.
The relationship between the roller length B and the width A in the connecting rod bearing direction in the first embodiment, and the diameter difference ΔD between the minimum diameter D0 of the rolling contact surface inner diameter and the rolling contact surface inner diameter DB at the roller end are 20 μm.
The following relationships are also applied in this embodiment. In this embodiment, since the recess 11 and the hole 12 are provided in the rod portion 2, the weight can be further reduced. Also,
Since the connecting rod 1A is punched by a fine blanking press, the punched surface does not require post-processing such as grinding, resulting in excellent productivity.

FIG. 9 shows still another embodiment of the present invention. In this embodiment, in the connecting rod with bearing 10 according to the embodiment shown in FIG. 6, the connecting rod width d and the length c of the connecting rod 8 are set to be substantially the same. By setting the relationship between the dimensions c and d in this way, the overhang portion of the large end portion 3 and the small end portion 4 is small, and as a result, the weight can be reduced, and the connecting rod 1 can be manufactured by pressing a metal flat plate. You can

FIG. 10 shows a connecting rod 1B according to still another embodiment of the present invention. This connecting rod 1B
Is punched and formed from a single steel plate, and the connecting rod outer peripheral surface S1 and the inner peripheral surface S2 of the through hole 5 are punched surfaces. This punching process is performed by a fine blanking press. Connecting rod outer peripheral surface S1
Is the end face of the entire outer circumference of the connecting rod 1B,
It is composed of both side surfaces of the rod portion 2 and outer peripheral surfaces of the large end portion 3 and the small end portion 4. The punching surface which is the outer peripheral surface S1 of the connecting rod and the inner peripheral surface S2 of the through hole 5 is shown in FIG.
As enlargedly shown in (B), it has a shear surface a and a fracture surface b, and has a connecting rod outer peripheral surface S1 and an inner peripheral surface S of the through hole 5.
The proportion of the fracture surface b in 2 is 20% or less in all cases. In the case of using a fine blanking press, in detail, the punching surface has a droop part c, a primary shearing surface a1, a fracture surface b, and a secondary shearing surface a2 in this order from the punch entrance side, and the punching side has an edge on the punch passing side. Return part e
Occurs. The punching surface is the secondary shear surface a2.
Inclination angle θ where the punch passage side expands at
Occurs and becomes a taper shape. This inclination angle θ is the breaking angle. The part of the primary shearing surface a1 in the stamped surface is also gentler than the inclination angle θ of the secondary shearing surface a2, but an inclination angle (not shown) in which the punch passing side widens is generated and becomes a tapered surface.

The center O1 of the outer diameter surface of the large end 3 and the small end 4 is eccentric to the rod O2 side with respect to the center O2 of the through hole 5 in the first embodiment (FIGS. 1 to 4). ) Is the same as that of the connecting rod 1. Further, the outer peripheral surfaces of the large end portion 3 and the small end portion 4 and the side surfaces on both sides at both ends of the rod portion 2 are each smoothly continuous by a concave curved surface R having an arcuate cross section. Is the same as.

A method of manufacturing the connecting rod 1B will be described. This connecting rod 1B has a large end portion 3 and a small end portion 4 each having a substantially circular outer diameter surface at both ends of a rod portion 2 by punching a steel plate with a fine blanking press. The portion 3 has a through hole 5. The punching of the outer periphery of the connecting rod 1B and the punching of the through hole 5 are performed at the same time.
Alternatively, the outer periphery may be punched after punching the through hole 5. After punching, heat treatment of the connecting rod 1B and post-processing of the through holes 5 in the large end portion 3 and the small end portion 4 are not performed. Depending on the required specifications, the outer periphery of the connecting rod 1B may be punched normally, and the through hole 5 may be processed by a fine blanking press. The fine blanking press is a method for punching by controlling the material flow in the sheared portion of the material to be punched, and is also called precision punching. About 5 for normal punching
A shear surface of about 0% is formed, but according to the fine blanking press, the fracture surface b on the punched surface
Is less than 20%. The material of the steel plate that is the material of the connecting rod 1B is cold rolled steel plate (SPCC
Etc.), carbon steel strip steel (SPHC etc.), carbon steel for machine structure (S16C, S22C to S35C etc.), chrome molybdenum steel (SCM etc.), etc., but the fine blanking press is more effective than ductile material. The best among the materials mentioned above are cold rolled steel plate (SPCC) and carbon steel strip steel (S
PHC) and carbon steel for machine structural use (S16C).

FIG. 11 is an explanatory view conceptually showing the fine blanking press. The fine blanking press is a plate retainer 13 having a knife edge-shaped protrusion 13a.
The reverse presser 14 and the punch 15 and the die 16 having extremely small clearances generate a high compressive stress inside the material W to enhance the ductility of the material W and prevent the occurrence of cracks. This is a method of obtaining a cross section. First, the protrusion 13a of the plate retainer 13 is pressed into the surface of the material near the contour to be punched ((A) in the figure). Then, the material W is pressed and fixed onto the die 16 by the projections 13a, and the reverse presser 14 is also operated at the same time to start punching ((B) in the same figure). The shearing process progresses as the punch 15 is further pushed. Since the reverse pressing 14 always pushes flat during processing, bending deformation is prevented. In addition, punch 1
The clearance between 5 and the die 16 is, for example, 3 to 5% of the plate thickness.
It is said that

According to the connecting rod 1B having this structure, the fracture surface b occupies 20% or less of the connecting rod outer peripheral surface S1 and the inner peripheral surface S2 of the through hole 5, so that it is a punched surface, but a processed surface. Is clean and accurate. Therefore, a bearing (not shown) can be fitted into the through hole 5 by press fitting or the like without performing post-processing. In this way, since it can be formed by punching and no post-processing is required, the manufacturing is simple and the man-hour and cost can be reduced.

FIG. 12 shows a roller bearing 20 in a connecting rod with a bearing according to still another embodiment of the present invention. In this connecting rod with bearing, the large end portion 3 and the small end portion 4 of the connecting rod 1B in the embodiment of FIG.
The roller bearing 20 shown in FIG. 12 is fitted into the through hole 5 of FIG. The roller bearing 20 includes an outer race 21 having a cylindrical rolling surface 21 a and a plurality of rollers 22 accommodated in the outer race 21.
And the plurality of rollers 22 are held in a pocket of an annular cage 23. The length of the roller 22 is not more than the thickness of the connecting rod 1B. The outer ring 21 is made of a machined steel material. The through hole 5 of the connecting rod 1B is slightly tapered by processing with a fine blanking press, but the rolling surface 21a of the outer ring 21 is restricted within a predetermined cylindricity range. The cylindricity is a value indicated by the maximum radial distance from the originally supposed geometrical cylindrical surface, and the predetermined cylindricity is 0.01 mm or less. The predetermined cylindricity is preferably 0.005 mm or less.

In this embodiment, the outer ring 21 has a radial thickness t that gradually changes along the axial direction, as shown in FIG. 12, corresponding to the tapered shape of the through hole 5 of the connecting rod 1B. In the example of FIG. 12, the outer ring 21 has a taper surface on the outer diameter surface 21b in a single state, so that the rolling surface 2
The inner diameter surface 1a is a cylindrical surface, and the thickness t in the radial direction gradually changes.

The operation of this embodiment will be described. The fine blanking press can obtain a beautiful sheared surface on the punched surface, but the through hole 5 of the connecting rod 1B is slightly tapered as described above. For example, a connecting rod 1B with a thickness of 4.8 mm has a diameter of 12 mm or 14 mm.
When the through hole 5 is provided, the both ends of the hole 5 are tapered with a diameter difference of about 20 μm. If a normal shell type bearing (not shown) is press-fitted into the tapered through hole 5, the outer ring follows the tapered through hole 5 and supports the rollers only on the smaller diameter side. , The bearing life will be shortened. In order to solve this problem, the radial thickness t of the outer race 21 is gradually changed as in the example of FIG. As a result, the tapered shape of the through hole 5 is canceled out,
The cylindricity of the rolling surface 21a is secured. Therefore, the load of the rollers 22 is made uniform over the entire length in the axial direction, and the life is long.

In this embodiment, the outer race 21 has a tapered outer diameter surface. However, as shown in FIG. 13, the inner race surface 21a of the outer race 21 has a rolling surface 21a.
The outer ring 2 can be
The radial thickness t of 1 may be gradually changed. In this case, the outer diameter surface of the outer ring 21 is a cylindrical surface. Thus, even if the inner surface of the outer ring 21 is tapered, the connecting rod 1B
When the outer ring 21 is deformed following the tapered shape of the through hole 5 when press-fitted into the through hole 5,
a becomes a cylindrical surface.

In the embodiments of FIGS. 12 and 13, the outer ring 21 of the bearing 20 is a machined product.
Instead of the bearing 20 of FIG. 13, as shown in FIG. 14, the outer ring 21A is a shell type roller bearing 20, that is, the outer ring 21.
A bearing in which A is a press-formed product of a steel plate may be used.
The outer ring 21A is provided with both collars. The shell-shaped outer ring 21A is such that the radial thickness t, which is the plate thickness, gradually changes in the axial direction. Even if it is a shell type,
The outer ring 21A may be configured such that either the outer peripheral surface or the inner peripheral surface has a tapered surface and the radial thickness t changes.

FIG. 15 shows a connecting rod with a bearing 10 according to still another embodiment of the present invention. In this connecting rod with bearing 10, the outer ring 21 of the roller bearing 20 has a radial thickness t that is uniform along the axial direction and has a radial thickness t that provides the predetermined cylindricity. The predetermined cylindricity is 0.01 mm or less as described above. Other configurations are the same as those of the embodiment shown in FIG. When the outer ring 21 has a small thickness, the outer diameter surface of the outer ring 21 completely follows the inner diameter surface of the through hole 5 of the connecting rod 1B as shown in FIG. Face 21
a is a tapered surface. However, when the thickness t of the outer ring 21 is thick to some extent, the outer diameter surface of the outer ring 21 does not follow the inner diameter surface of the through hole 5 and the cylindricity of the rolling surface 21a is secured, as shown in FIG. The thickness t of the outer ring 21 depends on various conditions.
The thickness is such that the cylindricity of the outer ring 21 is 0.01 mm or less while being pressed into

17 to 19 show still another embodiment of the present invention. This connecting rod with bearing 10 is shown in FIG.
In this embodiment, a plurality of (here, two) divided connecting rod parts 30A and 30B each having a large end portion 3, a small end portion 4 and a rod portion 2 are laminated to form a laminated body 30, and the large end portion 3 thereof is provided. By pressing the annular component 7A into the small end portion 4 and the small end portion 4, the divided connecting rod components 30A and 30B of the laminated body 30 are integrated to form the connecting rod 1C. That is, the annular connecting member 7A prevents the divided connecting rod members 30A and 30B from coming off from each other, and the connecting rod 1C is an assembled product.

The divided connecting rod parts 30A, 30B are
Both are flat plate-shaped parts having the same shape, and through holes 5 are formed in their large end portions 3 and small end portions 4. A bearing 6A is press-fitted into the inner diameter surface of these through holes 5. The eccentricity of the center O1 of the outer diameter surface of the large end portion 3 and the small end portion 4 to the rod portion 2 side with respect to the center O2 of the through hole 5 is the first embodiment (FIGS. 1 to 4). ) Is the same. Also, the outer peripheral surfaces of the large end portion 3 and the small end portion 4 and the side surfaces on both sides at both ends of the rod portion 2 are each smoothly continuous with a concave curved surface R having an arcuate cross section. This is the same as the first embodiment.

The bearing 6A is a shell type bearing, and the shell type outer ring is composed of the above-mentioned annular part 7A. Bearing 6A
Has a plurality of rollers 8 rolling along a rolling surface formed by the inner diameter surface of the outer ring which is the annular component 7A, and each roller 8 is held by a ring-shaped cage 9. The annular component 7A, which is a shell-type outer ring, is a press-formed product of a steel plate,
It has a collar 7Aa on both sides.

The divided connecting rod parts 30A and 30B are
A set of continuous sets of parts obtained by punching a steel plate, which is a material plate material, by a press and continuously punched from the same one steel plate by the same press die is used.

The outer peripheral surface of each of the divided connecting rod parts 30A, 30B and the punched surface which is the inner peripheral surface of the through hole 5 are
As enlarged and shown in FIG. 19, it has a shear surface q and a fracture surface r. When the divided connecting rod parts 30A and 30B are punched by a normal press, the punched surface is a pour portion p, a shear surface q, and a fracture surface r in order from the punch entrance side, and returns to the edge of the punch passage side. A part (burr) s occurs. In addition, the punched surface has a taper shape at the fracture surface r, where an inclination angle β that widens the punch passing side is generated.

Therefore, two divided connecting rod parts 30 are provided.
In this embodiment in which A and 30B are laminated to form a laminated body 30, each divided connecting rod component 3 located on the front and back of the connecting rod is used.
As shown in FIG. 18, 0A and 30B are laminated so that the sagging portion p generated by the press working faces the outside of the connecting rod 1C. As a result, the inner diameter expansion side of the through hole 5 of each of the divided connecting rod parts 30A and 30B faces the stacking side.

According to the connecting rod 1C having this structure, the divided connecting rod part 30 of the same shape made of a pressed product.
Since A and 30B are laminated to form the laminated body 30, the individual divided connecting rod parts 30A and 30B can be thinned, and the step difference between the sheared surface and the fracture surface due to the press working is reduced accordingly. In addition, each fracture surface will be dispersed. For this reason, the connecting rod 1C with high accuracy can be obtained in which the annular component 7A is not tilted even by ordinary press working. In this way, since ordinary press working can be used, the connecting rod 1C can be manufactured easily and inexpensively without the need for a special press die or press machine such as fine blanking.
Further, since the divided connecting rod parts 30A and 30B are integrated so as not to come off from each other by the press-fitting of the annular component 7A, it is not necessary to join the divided connecting rod parts 30A and 30B to each other. To be simplified.
Since the annular component 7A is composed of the outer ring of the bearing 6A in this embodiment, it is not necessary to provide an annular component separately from the bearing, and an increase in the number of components is avoided.

The divided connecting rod parts 30A and 30B are
Since two consecutive sheets punched from the same material plate material by the same press die are taken out as one set, the influence of the size change of the pressed product with the passage of time of the press work is small. It can be suppressed. Therefore, it is possible to minimize the dimensional difference between the divided connecting rod parts 30A and 30B used for one connecting rod 1C, and it is possible to assemble the connecting rod 1C with high accuracy.

Double-split connecting rod part 3 to be a laminated body 30
As shown in FIG. 18, since 0A and 30B are arranged so that the sagging portion p generated by the press working is outward, that is, the front surface side and the back surface side of the connecting rod, respectively, the inner diameter expansion side of the through hole 5 is the same. Since it faces inward, the cylindricity of the bearing mounting portion can be secured, and the bearing 6
A can be press-fitted and fitted. In addition, the return portions s are brought into contact with each other at the center and crushed, and the influence of the return portions s is eliminated. Since the nose p comes to the outside, it is possible to prevent injury when touched by hand.

FIG. 20 shows still another embodiment of the present invention. 17 to 19, the laminated body 30 of the connecting rod 1C is composed of three or more (five in the illustrated example) divided connecting rod parts 30A to 30E. Also in this case, each divided connecting rod component 30
Of the A to 30E, the two divided connecting rod parts 30A and 30E located on the front and back sides of the connecting rod are arranged so that the sagging portion p generated by press working faces the outside of the connecting rod 1C. In addition, even when three or more divided connecting rod parts 30A to 30E are stacked in this way, each divided connecting rod part 30A to 30E continuously takes out the divided connecting rod parts that are continuously punched out by the number of stacked layers and extracts them one by one. Assemble as one connecting rod 1C. Other configurations are the same as those of the embodiment shown in FIGS.

In the case of this structure, since the laminated body 30 of the connecting rod 1C is composed of the five divided connecting rod parts 30A to 30E, the divided connecting rod parts 30A to 30E are formed.
In the case of making a press-punched product, the plate thickness of the material plate material becomes thin, and the step difference between the sheared surface and the fracture surface of the punched surface becomes smaller, which is more accurate than the case of the embodiment of FIGS. 17 to 19. Easy to manufacture good connecting rod with bearing.
In this embodiment, the number of split connecting rod parts is set to 5
Although the number of the divided connecting rod parts to be laminated is not limited as long as it is two or more, the number of laminated parts is determined in consideration of the cost and the required shape. For example, the number may be three, or three or more.

FIG. 21 shows still another embodiment of the present invention. This embodiment is the same as the bearing connecting rod 10 (FIG. 17) of the embodiment of FIGS.
In this case, a needle roller 18 with a cage is arranged inside the outer ring 7 made of a solid circular tube. That is, the solid circular pipe 7 is used as an annular component that is press-fitted into the through holes 5 of the large end portion 3 and the small end portion 4 of the divided connecting rod components 30A and 30B. Needle roller with cage 18
The roller 8 and the cage 9 are assembled so as not to come off from each other. Other configurations are the same as those of the embodiment shown in FIGS.

Also in the case of this embodiment, the connecting rod 1C can be easily and inexpensively manufactured as an assembly product, and the connecting rod with bearing 10C can be manufactured with high accuracy, and the connecting rod with bearing 10 can be simply and inexpensively constructed.

FIG. 22 shows still another embodiment of the present invention. In this embodiment, in the bearing connecting rod 10 of the embodiment shown in FIGS. 17 to 19, the through holes 5 of the large end portion 3 and the small end portion 4 of the divided connecting rod components 30A and 30B are provided.
A dry metal 7C that serves as a slide bearing is used as an annular component that is press-fitted into. Other configurations are the same as those of the embodiment shown in FIGS. Also in this embodiment,
Similar to the embodiment of FIGS. 17 to 19, the connecting rod 1C can be manufactured easily and inexpensively, and the accuracy can be improved.
The bearing-equipped connecting rod 10 can be configured easily and inexpensively.

In each of the embodiments shown in FIGS. 21 and 22, the number of stacked divided connecting rod parts can be set to an arbitrary number. Further, in each of the embodiments shown in FIGS. 17 to 22, the annular component that is press-fitted into the divided connecting rod component and integrated with each other is used as the bearing component such as the bearing outer ring, but the connecting rod 1C in this case is The bearing may be installed on the inner circumference of the annular component press-fitted into the large end and the small end. Further, the respective divided connecting rod parts may be integrally formed by a ring-shaped part and may be joined to each other at other parts, whereby reinforcement can be achieved.

23 and 24 show still another embodiment of the present invention. In this connecting rod with bearing 10, the connecting rod 1D has a connecting rod body 31 of a cast product made of aluminum, and a cylindrical member 41 provided in a penetrating state in the inner diameter holes of the large end portion 3 and the small end portion 4 of the connecting rod body 31, respectively. Composed of and. The connecting rod body 31 is formed in a flat plate shape, for example. The cylindrical member 41 is made of steel such as bearing steel or low carbon steel, and is fixed to the connecting rod body 31 by casting the connecting rod body 31.
The length of the cylindrical member 41 is the same as the thickness of the corresponding large end 3 or small end 4. The rolling bearing 6 is attached to the cylindrical member 41 at the large end 3 and the small end 4 of the connecting rod 1D.
The bearing connecting rod 10 is configured by attaching C by press fitting. The inner diameter surface of the cylindrical member 41 constitutes the through hole 5 of the connecting rod 1D. The center O1 of the outer diameter surface of the large end portion 3 and the small end portion 4 is eccentric to the rod portion 2 side with respect to the center O2 of the through hole 5 in the first embodiment (FIGS. 1 to 1).
It is the same as FIG. 4). Further, the outer peripheral surfaces of the large end portion 3 and the small end portion 4 and the side surfaces on both sides at both ends of the rod portion 2 are each smoothly continuous with a concave curved surface R having an arcuate cross section. Is the same as the embodiment of.

The cylindrical member 41 has an uneven portion 41b on its outer diameter surface for engaging with the connecting rod body 31, as shown in FIG. 24 (A) or (B), for example. The concave-convex portion 41b may have any shape as long as it has a retaining function and a rotation-preventing function, but in the example shown in the figure, an inclined groove that extends in the circumferential direction of the cylindrical member 41 is inclined with respect to the axial direction of the cylindrical member 41. It is said that. The example of FIG. 24 (A) has an uneven portion 41b.
Is a spiral slant groove having two different slanting directions, and both slant grooves intersect each other. Figure 24
In the example of (B), the concavo-convex portion 41b is one spiral inclined groove. FIG. 24C is an enlarged view of a part of the uneven portion 41b formed of the inclined groove. The uneven portion 41b is
Instead of the inclined groove, an inclined ridge may be used as shown in an enlarged view in FIG. Although the concave and convex portion 41b formed of the inclined groove or the inclined concave portion is continuous for one round or more of the cylindrical member 41, it may be provided intermittently.
Further, a plurality of uneven portions 41b may be provided, and for example, the retaining portion and the rotation preventing portion may be separately formed. The inner diameter surface of the cylindrical member 41 may be a polished surface.

A method of manufacturing the connecting rod 1D having the above structure will be described. The connecting rod body 31 is cast by casting aluminum, for example, by a die casting method which is a kind of precision casting method. At the time of this casting, a cylindrical member 41 is placed in a mold (not shown), and the connecting rod body 31 is cast together with the cylindrical member 41, so that the large end portion 3 and the small end portion 4 of the connecting rod body 31 are respectively cylindrical members. 41
Is fixed. At this time, the connecting rod body 31 is cast in a state of meshing with the uneven portion 41b following the outer diameter surface of the cylindrical member 41, and is fixed to the cylindrical member 41.

Connecting rod body 31 manufactured in this way
Then, the rolling bearing 6C is press-fitted as described above. Various types of rolling bearings can be used as the rolling bearing 6C, for example, various roller bearings can be used. In this embodiment, a shell type roller bearing is used. Further, as the shell type bearing, a shell type needle roller bearing is used in detail.

Rolling bearing 6C comprising this shell type bearing
Has an outer ring 7A and a plurality of rollers 8 rolling along a raceway surface formed by the inner diameter surface of the outer ring 7A, and each roller 8 is held by a ring-shaped cage 9. The outer ring 7A is a shell type, that is, a press-formed product of a steel plate, and has a collar 7Aa on both sides. This rolling bearing 6C does not have an independent inner ring, and the roller 8 rolls on the outer diameter surface of the shaft that serves as the inner ring. The cage 9 is a press-formed product of steel plate,
In addition, a welded product, a resin molded product, or a shaving product may be used. In addition, the retainer 9 may be subjected to a display processing for preventing image sticking.

The width of the rolling bearing 6C is wider than the width (axial length) of the cylindrical member 41. The cylindrical member 41 may have a width substantially the same as the width of the rolling bearing 6C.

According to the connecting rod 1D having this structure, a highly rigid steel cylindrical member 41 is cast into the hole of the connecting rod main body 31 made of aluminum, and the rolling bearing 6C is formed in the inner diameter portion thereof.
Since it is press-fitted, aluminum having low rigidity and high thermal expansion coefficient can be used for the connecting rod body 31 while being used in combination with the rolling bearing 6C. That is, normally, if the cylindrical member is press-fitted into the connecting rod body made of aluminum, it will come out due to the difference in the coefficient of thermal expansion when the temperature rises. Since the connecting rod body 31 is cast together at the time of casting, the connecting rod body 31 is cast in a state of meshing with the uneven portion 41b following the outer diameter surface of the cylindrical member 41, and is fixed to the cylindrical member 41. In this way, the meshing state of the uneven portion 41b allows the meshing state of the uneven portion 41b to be maintained even when the temperature rises, regardless of the difference in thermal expansion coefficient between the steel cylindrical member 41 and the aluminum connecting rod body 31. The cylindrical member 41 does not come out. Further, the cylindrical member 41 does not rotate. In particular, the uneven portion 41b
Is an inclined groove or an inclined ridge extending in the circumferential direction, the effect of maintaining meshing with respect to the difference in thermal expansion when the temperature rises is high. The rolling bearing 6C arranged on the inner diameter surface of the cylindrical member 41 functions as a bearing for the large end portion 3 and the small end portion 4. If the cylindrical member 41 and the outer ring 7A of the rolling bearing 6C are made of materials having the same coefficient of thermal expansion, there is no concern that the rolling bearing 6C will come off.

Since the connecting rod 1D uses aluminum for the connecting rod body 31, the connecting rod 1D can be made significantly lighter than steel and the responsiveness of the engine is improved. If the thickness of the cylindrical member 41 is increased to some extent, the rolling bearing 6 can be manufactured due to the rigidity of the cylindrical member 41 even if the connecting rod body 31 is thin.
The backup function of C is secured. Rolling bearing 6C
Even if is a shell type needle roller bearing, the necessary back-up action is secured. As described above, since the connecting rod main body 31 can be made thin, the connecting rod 1D is further reduced in weight, and the responsiveness of the engine is improved.
Compact settings are possible.

In the above embodiment, the length of the cylindrical member 41 is the same as the plate thickness of the connecting rod body 31.
As shown in (A), the cylindrical member 41 is connected to the connecting rod body 3
It may be longer than the plate thickness of 1. For example, the cylindrical member 41
Is approximately the same length as the width of the rolling bearing 6C press-fitted therein. Further, as shown in FIG. 25 (B), the large end portion 3 and the small end portion 4 of the connecting rod main body 31 are provided with two facing pieces 50.
Alternatively, the cylindrical member 41 may be fixed to the opposing pieces 50 by casting the connecting rod body 31 in the same manner as described above. Further, in each of the above-described embodiments, the large end portion 3 and the small end portion 4 of the connecting rod body 31.
Although the cylindrical member 41 is provided on both of them and the rolling bearing 6C is press-fitted, the cylindrical member 41 having the above-described configuration is provided on only one of the large end portion 3 and the small end portion 4 to press-fit the rolling bearing 6C, and the other end is It may be a plain bearing as in the conventional example.

FIG. 26 shows still another embodiment of the present invention. In this embodiment, in the connecting rod with bearing 10 of the embodiment shown in FIGS. 23 and 24, as the rolling bearing 6D, a roller bearing in which a roller 8 held by a cage 9 is arranged inside an outer ring 7 without a collar. Is used. The roller 8 is, for example, a needle roller. The outer ring 7 is made of, for example, a solid circular pipe. The axial length of the cylindrical member 41 fixed to the large end 3 side of the connecting rod body 31 is determined by the connecting rod body 31.
The axial length of the cylindrical member 41 fixed to the small end 4 side is the same as the plate thickness of the connecting rod body 31. Other configurations are the same as those of the embodiment shown in FIGS. 23 and 24.

Also in the case of this embodiment, similarly to the embodiments of FIGS. 23 and 24, the weight can be reduced, and the rolling bearing 6D does not come off the rolling bearing 6D from the connecting rod body 31 when the temperature rises. In addition, in this embodiment, since the outer ring 7 of the rolling bearing 6D does not have a collar, the inflow / outflow of the lubricating oil to / from the bearing 6D becomes easy, and seizure resistance is improved. Cylindrical member 41 on the large end 3 side
Is approximately the entire width of the rolling bearing 6D,
The effect of backing up the rolling bearing 6D by the cylindrical member 41 is high.

FIG. 27 shows still another embodiment of the present invention. In this embodiment, the cage roller 18 is arranged in the through hole 5 which is the inner diameter surface of the cylindrical member 41 of the connecting rod 1D in the embodiment of FIGS. 23 and 24, and the through hole 5 which is the inner diameter surface of the cylindrical member 41 is formed. The bearing raceway surface is used.
The cage-equipped roller 18 is a component in which the cage 9 holds a plurality of rollers 8. The inner diameter surface of the cylindrical member 41 is preferably a polishing surface. The axial length of the cylindrical member 41 is made longer than the plate thickness of the connecting rod body 31, and is adapted to the axial length of the roller 8 with cage. The cylindrical member 41 and the roller 8 with the cage form a rolling bearing 6E. Other configurations are the same as those of the embodiment shown in FIGS. 23 and 24.

In the case of this embodiment, the cylindrical member 41 functions as the outer ring of the rolling bearing 6E. Since the cylindrical member 41 is made of steel, it is possible to obtain the surface hardness required for the raceway surface on the inner diameter surface, and also secure the rigidity required for the raceway ring. In addition, in this embodiment, the rolling bearing 6E is configured by inserting the roller 18 with a retainer into the cylindrical member 41, and since there is no collar, the inflow and outflow of the lubricating oil into the bearing 6E is easy. Is effective in improving seizure resistance.

[0066]

The connecting rod of the present invention has a large end portion and a small end portion each having a substantially circular outer diameter surface at both ends of the rod portion, and the large end portion and the small end portion are provided with through holes. Since it is a connecting rod, the center of the outer diameter surface at the large end and the small end is eccentric to the rod portion side with respect to the center of the through hole. . The connecting rod is formed from one steel plate, the through hole is a punched surface, has a shear surface and a fracture surface, and the ratio of the fracture surface on the inner peripheral surface of the through hole is 20% or less. In this case, it can be formed by punching, there is no need for post-processing of the processed surface, manufacturing is simple, and man-hours and costs are reduced. The connecting rod is formed by stacking divided connecting rod parts each having a large end portion, a small end portion, and a rod portion, and press-fitting annular parts at the large end portion and the small end portion of the laminated body of the divided connecting rod parts, respectively. When the divided connecting rod parts are integrated, the connecting rod can be manufactured easily and inexpensively. The connecting rod includes a connecting rod body of a cast aluminum product, and a cylindrical member provided in a penetrating state on either or both of the large end portion and the small end portion of the connecting rod body, and the cylindrical member has an outer diameter. If there is an uneven part for meshing with the connecting rod body on the surface and it is fixed to this connecting rod body by casting the connecting rod body, it is possible to reduce the weight, improve productivity, and use rolling bearings. It can be done without any trouble. Since the connecting rod with a bearing of the present invention uses the connecting rod of the present invention and the rolling bearings are fitted in the through holes of the large end portion and the small end portion, the connecting rod with a bearing can be made lightweight and compact. The rolling bearing has an outer ring and a plurality of rollers rolling along the rolling surface of the outer ring, and the length of the rollers is longer than the width of the connecting rod in the through hole penetrating direction. It is possible to achieve both further weight reduction and longer life.

[Brief description of drawings]

FIG. 1 is a plan view of a connecting rod according to a first embodiment of the present invention.

2A and 2B are a cross-sectional view and a front view of a bearing-equipped connecting rod in which a bearing is fitted in a through hole of the connecting rod.

FIG. 3 is a partially enlarged sectional view of the bearing-equipped connecting rod.

FIG. 4 is a sectional view showing a part of FIG. 3 in a further enlarged manner.

FIG. 5 is an explanatory diagram showing a deformed state of the outer ring of the connecting rod with bearings.

FIG. 6 is a cross-sectional view of a bearing-equipped connecting rod according to another embodiment of the present invention.

FIG. 7 is a front view of a connecting rod according to still another embodiment of the present invention.

FIG. 8 is a cross-sectional view of the connecting rod.

FIG. 9 is a sectional view of a bearing-equipped connecting rod according to still another embodiment of the present invention.

10A is a perspective view of a connecting rod according to still another embodiment of the present invention, and FIG. 10B is an enlarged explanatory view of a punched surface thereof.

FIG. 11 is a process drawing conceptually showing a fine blanking press.

FIG. 12 is a sectional view of an example of a roller bearing in a connecting rod with a bearing according to still another embodiment of the present invention.

FIG. 13 is a cross-sectional view of another example of the roller bearing in the connecting rod with the bearing.

FIG. 14 is still another cross-sectional view of the roller bearing in the connecting rod with the bearing.

FIG. 15 is a partial cross-sectional view of a bearing-equipped connecting rod according to still another embodiment of the present invention.

FIG. 16 is a partial cross-sectional view of a connecting rod with bearing serving as a comparative reference example.

17A and 17B are a sectional view and a front view, respectively, of a connecting rod with a bearing according to still another embodiment of the present invention.

FIG. 18 is a partially enlarged sectional view of the bearing-equipped connecting rod.

FIG. 19 is an enlarged cross-sectional view showing a punched surface of a split connecting rod part of the connecting rod with bearings.

FIG. 20 is a cross-sectional view of a bearing-equipped connecting rod according to still another embodiment of the present invention.

FIG. 21 is a sectional view of a bearing-equipped connecting rod according to yet another embodiment of the present invention.

FIG. 22 is a sectional view of a bearing-equipped connecting rod according to yet another embodiment of the present invention.

23A and 23B are a sectional view and a front view, respectively, of a bearing-equipped connecting rod according to still another embodiment of the present invention.

FIGS. 24 (A) and 24 (B) are front views showing examples of the concavo-convex portion of the cylindrical member in the connecting rod; FIG. 24 (C) is a partially enlarged view of an inclined groove which is an example of the concavo-convex portion; FIG. 7 is a partially enlarged view of an inclined ridge which is another example of the uneven portion.

25A and 25B are a partially enlarged side view and a partially enlarged perspective view, respectively, showing various modified examples of the connecting rod.

26 (A) and (B) are respectively a sectional view and a front view of a bearing-equipped connecting rod according to still another embodiment of the present invention.

27 (A) and 27 (B) are a sectional view and a front view, respectively, of a connecting rod with a bearing according to yet another embodiment of the present invention.

FIG. 28 is a plan view of a connecting rod of a conventional example.

[Explanation of symbols]

1-1D ... connecting rod 2 ... Rod 3 ... Large end 4 ... Small edge 5 ... Through hole 6 to 6E ... Bearing 7 ... Outer ring 7A ... Outer ring (annular part) 7C ... Dry metal (annular parts) 8 ... 9 ... Cage 10 ... Connecting rod with bearing 20 ... Roller bearing 21,21A ... Outer ring 22 ... 23 ... Cage 30A, 30B ... Split connecting rod parts 30 ... laminated body 31 ... Connecting rod body 41 ... Cylindrical member 41b ... uneven portion O1 ... Outer diameter center of large end and small end O2 ... through hole center R ... concave curved surface a ... Shear surface b ... fracture surface

Claims (8)

[Claims] 1. A connecting rod comprising a large end portion and a small end portion having substantially circular outer diameter surfaces at both ends of the rod portion, and the large end portion and the small end portion being provided with through holes, wherein the large end portion is provided. A connecting rod in which the center of the outer diameter surface of the portion and the small end portion is eccentric to the rod portion side with respect to the center of the through hole. 2. The connecting rod according to claim 1, wherein
A connecting rod having an outer peripheral surface where the outer diameter surfaces of the large end portion and the small end portion and the side surfaces on both sides at both ends of the rod portion are smoothly continuous with a concave curved surface having an arcuate cross section. 3. The connecting rod according to claim 1 or 2, wherein the through hole is formed of a single steel plate, and the through hole is a punched surface having a shear surface and a fracture surface. 20% of the fracture surface occupies the inner surface
A connecting rod that is: 4. The connecting rod according to claim 3, wherein
A connecting rod in which the outer peripheral surface of the connecting rod is a punched surface, has a shearing surface and a fracture surface, and the ratio of the fracture surface on the outer peripheral surface of the connecting rod is 20% or less. 5. The connecting rod according to claim 1, wherein divided connecting rod parts each having a large end portion, a small end portion, and a rod portion are laminated, and a laminated body of the divided connecting rod parts is formed. A connecting rod in which the split connecting rod parts are integrated by press-fitting annular parts into the large end and the small end, respectively. 6. The connecting rod according to claim 1 or 2, wherein the connecting rod main body of the cast aluminum product and the large end portion and / or the small end portion of the connecting rod body are provided in a penetrating state. And a cylindrical member, wherein the cylindrical member has an uneven portion for meshing with the connecting rod body on the outer diameter surface, and is fixed to the connecting rod body by casting the connecting rod body. 7. The connecting rod according to any one of claims 1 to 6, wherein a rolling bearing is fitted in each of the through holes of the large end portion and the small end portion. 8. The connecting rod with a bearing according to claim 7, wherein the rolling bearing has an outer ring and a plurality of rollers rolling along a rolling surface of the outer ring, and the length of the roller is the above. Connecting rod longer than the width of the connecting rod through hole.