JP2003194037A - Connecting rod and connecting rod with bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a connecting rod with reduced weight, improved productivity and for use with a ball bearing and to provide a connecting rod with the bearing. <P>SOLUTION: The connecting rod 2 comprises a cast connecting rod body 3 of aluminum and a cylindrical member 4 fixed to the connecting rod body. The cylindrical member 4 is provided on each of a large end portion 3a and a small end portion 3b or on either one of them. The cylindrical member 4 has in an outer cylindrical surface thereof corrugations for engagement with the connecting rod body 3 and is fixed to the connecting rod body 3 through casting of the connecting rod body 3. An inner cylindrical surface 4a of the cylindrical member 4 serves as a fitting surface for press fitting of the ball bearing 5. Alternatively to the press fitting of the ball bearing 5, rollers with a retainer may be arranged so that the cylindrical member 4 is used as an outer race of the bearing. <P>COPYRIGHT: (C)2003,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, a connecting rod with a bearing thereof, and a method of manufacturing the connecting rod.

[0002]

2. Description of the Related Art Conventionally, in connecting rods for such applications, aluminum connecting rods have been used to reduce the weight, and the bearings at the large end portion and the small end portion are Most are used as plain bearings. In order to improve the responsiveness of the engine, it is an effective means to reduce the frictional resistance by changing the bearing of the connecting rod from a sliding bearing to a rolling bearing.

However, in the hole of the aluminum connecting rod,
When the steel outer ring of a rolling bearing such as a shell type bearing is press-fitted, the bearing will come out of the connecting rod due to the difference in thermal expansion coefficient when the temperature rises. Further, it is not possible to use the inner diameter surface of the hole of the aluminum connecting rod as the raceway surface of the rolling element in the rolling bearing because the surface hardness of the raceway surface cannot be secured. From such a background, a combination of an aluminum connecting rod and a rolling bearing has not been proposed so far.

An object of the present invention is to provide a connecting rod which can be reduced in weight, has high productivity, and can be used for rolling bearings,
And a connecting rod with a bearing thereof.
Another object of the present invention is to provide a connecting rod manufacturing method capable of manufacturing the connecting rod of the present invention with high productivity.

[0005]

SUMMARY OF THE INVENTION A connecting rod of the present invention comprises a connecting rod body made of cast aluminum 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. With. It is assumed that 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. The uneven portion may be a concave portion, a convex portion, or both. In addition, the above cast aluminum product,
It is meant to include a cast product of an alloy containing aluminum as a main component. The connecting rod having this configuration 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, when the cylindrical member is made of steel, the rigidity and surface hardness required for the raceway surface of the rolling bearing can be secured, which also enables the use in combination with the rolling bearing. Further, since the connecting rod main body of this connecting rod is made of aluminum, the connecting rod can be made significantly lighter than that made 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 irregularities on the outer diameter surface of the cylindrical member are preferably shaped so as to obtain both the function of preventing the cylindrical member from slipping off and the function of 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. When the concavo-convex portion is such a slanted groove or slanted ridge, both functions of preventing the cylindrical member from rotating and coming off of the connecting rod body can be obtained, and the concavo-convex portion can be easily formed.

The first connecting rod with bearing according to the present invention is one in which a shell type roller bearing is press-fitted into the inner diameter surface of the cylindrical member of the connecting rod having any one of the above-mentioned configurations of the present invention. The shell type roller bearing is an inexpensive and lightweight rolling bearing, but the outer ring needs to be press-fitted and fixed, and the outer ring follows the inner diameter surface of the mounting hole, so the rigidity of the mounting hole is required. In the connecting rod provided with the above-mentioned cylindrical member, the cylindrical member is made of steel, so that there is no fear of the shell type bearing coming off and it is easy to secure the rigidity of the mounting hole.

A second connecting rod with a bearing according to the present invention is one in which a roller with a cage is arranged on the inner diameter surface of a cylindrical member of the connecting rod having any one of the above-described configurations of the present invention. The roller with cage is a component in which the cage holds a plurality of rollers, and is arranged in a state in which the rollers are in rolling contact with the inner diameter surface. In the case of this configuration, the cylindrical member functions as the outer ring of the rolling bearing. When a roller with a retainer is combined with the cylindrical member, the flange is eliminated, so that the inflow and outflow of lubricating oil is facilitated, and seizure resistance is improved.

The method of manufacturing a connecting rod of the present invention comprises a connecting rod main body of a cast aluminum product, and a cylindrical member provided in the large end portion and / or the small end portion of the connecting rod body in a penetrating state. A method for manufacturing a connecting rod, wherein the cylindrical member has an uneven portion for engaging with the connecting rod body on an outer diameter surface,
The cylindrical member is arranged in a mold of the connecting rod body and fixed to the connecting rod body by casting the connecting rod body. According to this manufacturing method, when the connecting rod body is cast, the connecting rod body is cast in a state of meshing with the concave-convex portion along the outer diameter surface of the cylindrical member and fixed to the cylindrical member. Therefore, in manufacturing a connecting rod including a connecting rod body and a cylindrical member, it is not necessary to separately provide a step of fixing the cylindrical member, and the productivity is good.

[0010]

1 is a block diagram of a first embodiment of the present invention.
And it demonstrates with FIG. The connecting rod 2 is composed of a connecting rod main body 3 made of cast aluminum and a cylindrical member 4 provided in a penetrating state in the inner diameter holes of the large end portion 3a and the small end portion 3b of the connecting rod body 3. The connecting rod body 3 is formed in a flat plate shape, for example.
The cylindrical member 4 is made of steel such as bearing steel or low carbon steel, and is fixed to the connecting rod body 3 by casting the connecting rod body 3. The length of the cylindrical member 4 is the same as the thickness of the corresponding large end portion 3a or small end portion 3b. The rolling bearing 5 is attached to the cylindrical members 4 of the large end portion 3a and the small end portion 3b of the connecting rod 2 by press fitting to form the connecting rod with bearing 1.

The cylindrical member 4 has, for example, as shown in FIG.
As shown in (A) or (B), it has an uneven portion 4b for engaging with the connecting rod body 3. Uneven portion 4b
Although any shape may be used as long as it has a function of preventing slipping out and preventing rotation, in the example shown in the figure, it is formed as an inclined groove that is inclined with respect to the axial direction of the cylindrical member 4 and extends in the circumferential direction of the cylindrical member 4. There is. In the example of FIG. 2A, the concave-convex portion 4b is formed by two spiral inclined grooves having different inclination directions, and both inclined grooves intersect with each other. The example of FIG. 2B shows an example in which the concave-convex portion 4b has one spiral inclined groove. Figure 2 (C)
Shows an enlarged view of a part of the uneven portion 4b composed of the inclined groove. The concavo-convex portion 4b may be an inclined ridge as shown in an enlarged view in FIG. In addition, the concave-convex portion 4b composed of the inclined groove or the inclined concave portion
Although the cylindrical member 4 is continuous over one round or more, it may be provided intermittently. Further, a plurality of uneven portions 4b 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 4 may be a polishing surface.

A method of manufacturing the connecting rod 2 having the above structure will be described. The connecting rod body 2 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 mold (not shown)
By disposing the cylindrical member 4 in the cylindrical member 4 and casting the connecting rod body 3 together with the cylindrical member 4, the cylindrical member 4 is fixed to the large end portion 3a and the small end portion 3b of the connecting rod body 3, respectively. At this time, the connecting rod body 3 is cast in a state of meshing with the uneven portion 4b following the outer diameter surface of the cylindrical member 4, and is fixed to the cylindrical member 4.

Connecting rod body 3 manufactured in this way
Then, the rolling bearing 5 is press-fitted as described above. Various types of rolling bearings can be used as the rolling bearing 5, for example, various roller bearings can be used. In this embodiment, a shell type roller bearing is used. Also, as this shell type bearing,
Specifically, a shell type needle roller bearing is used.

Rolling bearing 5 comprising this shell type bearing
Has an outer ring 6 and a plurality of rollers 7 rolling along a raceway surface formed by an inner diameter surface of the outer ring 6, and each roller 7 is held by a ring-shaped cage 8. The outer ring 6 is a shell type, that is, a press-formed product of a steel plate, and has a collar 6 on both sides.
a. The rolling bearing 5 does not have an independent inner ring, and the roller 7 rolls on the outer diameter surface of the shaft that serves as the inner ring. The cage 8 is a press-formed product of a steel plate, but in addition to this, it may be a welded product, a resin molded product, or a scraped product. In addition, the retainer 8 may be subjected to a display processing for preventing image sticking.

The width of the rolling bearing 5 is wider than the width (axial length) of the cylindrical member 4. The cylindrical member 4 may have a width substantially the same as the width of the rolling bearing 5.

According to the connecting rod 2 having this structure, since the cylindrical member 4 made of steel having high rigidity is cast into the hole of the connecting rod body 3 made of aluminum and the rolling bearing 5 is press-fitted into the inner diameter portion thereof, the rigidity is low. While using aluminum with a high coefficient of thermal expansion for the connecting rod body 3, the rolling bearing 5
Can be used in combination with. That is, normally, if the cylindrical member is press-fitted into the aluminum connecting rod body,
It will come out due to the difference in thermal expansion coefficient when the temperature rises,
In this embodiment, since the cylindrical member 4 having the uneven portion 4b on the outer diameter surface is cast together when the connecting rod body 3 is cast, the connecting rod body 3 follows the outer diameter surface of the cylindrical member 4 and the uneven portion 4b. It is cast in a state of meshing with and is fixed to the cylindrical member 4. In this way, the meshing state of the uneven portion 4b allows the meshing state of the uneven portion 4b to be maintained even when the temperature rises, regardless of the difference in thermal expansion coefficient between the steel cylindrical member 4 and the aluminum connecting rod body 3. The cylindrical member 4 does not come out. Further, the cylindrical member 4 does not rotate. In particular,
When the uneven portion 4b 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 5 arranged on the inner diameter surface of the cylindrical member 4 functions as a bearing for the large end portion 3a and the small end portion 3b. If the cylindrical member 4 and the outer ring 6 of the rolling bearing 5 are made of materials having the same coefficient of thermal expansion, the rolling bearing 5 will not come off.

Since the connecting rod 2 uses aluminum for the connecting rod body 3, the connecting rod 2 can be made significantly lighter than steel and the responsiveness of the engine is improved. If the cylindrical member 4 is made thick to some extent, the rigidity of the cylindrical member 4 ensures the backup function of the rolling bearing 5 even if the connecting rod body 3 is thin. Even if the rolling bearing 5 is a shell type needle roller bearing, the necessary backup action is secured. In this way, the connecting rod body 3 can be made thin, which leads to further weight reduction of the connecting rod 2,
The responsiveness of the engine is improved and a compact setting is possible.

Although the length of the cylindrical member 4 is the same as the plate thickness of the connecting rod body 3 in the above embodiment, FIG.
As shown in, the cylindrical member 4 may be longer than the plate thickness of the connecting rod body 3. For example, the cylindrical member 4 has substantially the same length as the width of the rolling bearing 5 press-fitted therein. Further, as shown in FIG. 3 (B), the connecting rod body 3 has a large end portion 3a and a small end portion 3b formed into a bifurcated shape composed of two facing pieces 10. Alternatively, the cylindrical member 4 may be fixed by casting the connecting rod body 3. Further, in each of the above embodiments, the cylindrical member 4 is provided on both the large end portion 3a and the small end portion 3b of the connecting rod body 3 and the rolling bearing 5 is press-fitted, but only one of the large end portion 3a and the small end portion 3b is provided. The rolling bearing 5 may be press-fitted with the cylindrical member 4 having the above-described structure, and the other may be a sliding bearing as in the conventional example.

FIG. 4 shows another embodiment of the present invention.
In this embodiment, in the connecting rod with bearing 1 of the first embodiment, as the rolling bearing 5, a roller bearing in which the rollers 7 held by the cage 8 are arranged inside the outer ring 6A without a collar is used. The roller 7 is, for example, a needle roller. The outer ring 6A is made of, for example, a solid circular tube. The axial length of the cylindrical member 4 fixed to the large end portion 3a side of the connecting rod body 3 is longer than the plate thickness of the connecting rod body 3, and the axial length of the cylindrical member 4 fixed to the small end portion 3b side is It has the same length as the plate thickness of the connecting rod body 3. Other configurations are the same as those in the first embodiment.

Also in the case of this embodiment, as in the first embodiment, the weight can be reduced, and the rolling bearing 5 with the bearing can be prevented from coming off from the connecting rod body 3 when the temperature rises. Further, in this embodiment, the rolling bearing 5
Since the outer ring 6A has no brim, the lubricating oil can easily flow into and out of the bearing 5, which is effective in improving seizure resistance. Since the cylindrical member 4 on the side of the large end portion 3a has substantially the entire width of the rolling bearing 5, the effect of backing up the rolling bearing 5 by the cylindrical member 4 is high.

FIG. 5 shows still another embodiment of the present invention. In this embodiment, a roller 9 with a retainer is arranged on the inner diameter surface 4a of the cylindrical member 4 of the connecting rod 2 in the first embodiment, and the inner peripheral surface 4a of the cylindrical member 4 is used as a bearing raceway surface. The caged roller 9 is a component in which the cage 8 holds a plurality of rollers 7. The inner diameter surface of the cylindrical member 4 is preferably a polished surface. The axial length of the cylindrical member 4 is
It is longer than the plate thickness of the connecting rod body 3 and has rollers 9
According to the axial length of. The cylindrical member 4 and the roller 9 with the cage form a rolling bearing 5. Other configurations are the same as those in the first embodiment.

In this embodiment, the cylindrical member 4 functions as the outer ring of the rolling bearing 5. Since the cylindrical member 4 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. Further, in this embodiment, the rolling bearing 5 is configured by inserting the roller 9 with a retainer into the cylindrical member 4, and since there is no collar, the inflow and outflow of the lubricating oil into the bearing 5 is easy. Is effective in improving seizure resistance.

[0023]

The connecting rod of the present invention comprises a connecting rod body made of cast aluminum, 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. The cylindrical member is
Since the outer diameter surface has irregularities for meshing with the connecting rod body and is fixed to the 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. When the concave-convex portion is an inclined groove or an inclined ridge that extends in the circumferential direction of the cylindrical member by inclining with respect to the axial direction of the cylindrical member, both rotation prevention and retaining of the cylindrical member with respect to the connecting rod body are prevented. The action is obtained, and the concavo-convex portion is easily formed. The first connecting rod with bearing in this invention has a shell type roller bearing press-fitted into the inner diameter surface of the cylindrical member in the connecting rod of any one of the above-mentioned configurations of the present invention. It is possible to use a shell type roller bearing, which is an inexpensive and lightweight rolling bearing, without causing the problem of
Cost can be reduced. Since the second connecting rod with a bearing of the present invention has a roller with a cage arranged on the inner diameter surface of the cylindrical member in the connecting rod of any one of the above configurations of the present invention, the cylindrical member is used as an outer ring of a rolling bearing. As a result, a connecting rod with a rolling bearing having a simple structure can be obtained, and lubricating oil can easily flow into and out of the bearing, and seizure resistance can be improved. A method for manufacturing a connecting rod according to the present invention is a method for manufacturing a connecting rod including a connecting rod main body of a cast aluminum product, and a cylindrical member provided in a penetrating state on either or both of a large end portion and a small end portion of the connecting rod body. In the method, the cylindrical member has an uneven portion for meshing with the connecting rod body on the outer diameter surface, and the cylindrical member is arranged in a mold of the connecting rod body and fixed to the connecting rod body by casting the connecting rod body. Therefore, the connecting rod of the present invention can be manufactured with high productivity.

[Brief description of drawings]

1A and 1B are a sectional view and a front view of a connecting rod with a bearing according to a first embodiment of the present invention, respectively.

2 (A) and 2 (B) are front views showing examples of the concavo-convex portion of the cylindrical member in the connecting rod, FIG. 2 (C) is a partially enlarged view of an inclined groove which is an example of the concavo-convex portion, and FIG. FIG. 7 is a partially enlarged view of an inclined ridge which is another example of the uneven portion.

3A and 3B are a partially enlarged side view and a partially enlarged perspective view, respectively, showing various modified examples of the connecting rod.

4A and 4B are a sectional view and a front view of a bearing-equipped connecting rod according to another embodiment of the present invention.

5A and 5B are a sectional view and a front view, respectively, of a bearing-equipped connecting rod according to yet another embodiment of the present invention.

[Explanation of symbols]

1 ... bearing connecting rod 2 ... connecting rod 3 ... Connecting rod body 3a ... Large end 3b ... small end 4 ... Cylindrical member 4b ... uneven portion 5 ... Rolling bearing 6 ... Outer ring 7 ... Needle rollers 8 ... Cage 9 ... Roller with cage

Continued front page    F term (reference) 3J033 AA04 AB04 AC01 EA10 EB03                 3J101 AA13 AA24 AA32 AA42 AA52                       AA62 AA72 BA54 BA56 FA33                       FA44 FA51 GA22

Claims (5)

[Claims] 1. A connecting rod body of a cast aluminum product, and a cylindrical member that is provided in a penetrating state on either or both of the large end portion and the small end portion of the connecting rod body. A connecting rod that has an uneven portion for meshing with the connecting rod body on its radial surface and is fixed to the connecting rod body by casting the connecting rod body. 2. The connecting rod according to claim 1, wherein the concavo-convex portion is 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. 3. A connecting rod with a bearing in which a shell type roller bearing is press-fitted into the inner diameter surface of the cylindrical member in the connecting rod according to claim 1 or 2. 4. A roller with a retainer, comprising a plurality of rollers retained by a retainer, on the inner diameter surface of the cylindrical member of the connecting rod according to claim 1 or 2, wherein the roller is rolled onto the inner diameter surface. Connecting rod with bearings arranged in contact with each other. 5. A method of manufacturing a connecting rod, comprising: a connecting rod body of a cast aluminum product; and a cylindrical member provided in a penetrating state on either or both of a large end portion and a small end portion of the connecting rod body. The cylindrical member has an uneven portion for meshing with the connecting rod body on the outer diameter surface, and the cylindrical member is arranged in a mold of the connecting rod body and fixed to the connecting rod body by casting the connecting rod body. And a method for manufacturing a connecting rod.