JP4064335B2 - Connecting rod for internal combustion engine and internal combustion engine - Google Patents

Description

The present invention relates to a connecting rod for an internal combustion engine and an internal combustion engine .

As a conventional connecting rod for an internal combustion engine, a connecting rod connected to a piston through a spherical joint is known (for example, see Patent Document 1).
JP-A-9-144879

FIG. 1 of Patent Document 1 will be described with reference to FIG. In addition, the code | symbol was reassigned.
FIG. 7 is a cross-sectional view showing a conventional connecting rod for an internal combustion engine. The connecting rod 200 is a member in which a convex spherical surface 202 is formed on a small end 201, and this convex spherical surface 202 is formed on a concave spherical surface 204 provided on the piston 203 side. Fits slidably. That is, the connecting rod 200 and the piston 203 are connected by a spherical joint 205 having a convex spherical surface 202 and a concave spherical surface 204.

The connecting rod 200 described above swings as the piston 203 reciprocates, and rotates a crankshaft (not shown).
Therefore, if the weight of the main motion system parts (parts that transmit force in the internal combustion engine) such as the connecting rod 200, the piston 203, and the crankshaft can be reduced, the respective inertial forces are reduced, and the parts that support these parts. The output to the engine can be reduced, and the output can be increased by increasing the rotation speed of the internal combustion engine.

  SUMMARY OF THE INVENTION An object of the present invention is to make it possible to comprehensively reduce the weight of a main motion system component connected to a connecting rod as well as the connecting rod itself.

The invention according to claim 1 is an internal combustion engine comprising a small end portion connected to a piston, a large end portion connected to a crankpin of a crankshaft, and rod portions respectively connecting the small end portion and the large end portion. In the connecting rod for use, the connecting rod is formed by joining a pair of integrally formed connecting rod halves divided in the thickness direction, and provided with a spherical surface constituting a spherical joint for connecting to the piston at the small end, The large end portion is an integral annular portion that fits into a separable crankpin that constitutes an assembled crankshaft, and the small end portion, the large end portion, and the rod portion are each provided with a hollow portion. .

  The small end, large end and rod of the connecting rod are connected together to simplify the structure, reduce the number of parts, and reduce the weight of the connecting rod. In addition, a spherical surface that forms a spherical joint for connecting to the piston is provided at the small end portion. For example, compared to a structure in which two pin boss portions of the piston are connected to the small end portion of the connecting rod via a piston pin. In the invention, the piston side is formed of a spherical surface constituting a spherical joint, a holding member for holding a small end, and a fastening member for fastening the holding member to the piston side, that is, a moving direction of the piston through the center of the piston. By adopting an axisymmetric shape that is symmetric with respect to the piston axis extending in the direction, the piston itself and the connecting structure of the piston and the connecting rod become lighter. Furthermore, the large end portion is formed as an integral annular portion that fits into a split crankpin, and a hollow portion is formed at the end portion of the split crankpin to reduce the weight of the crankshaft.

In addition, a hollow portion is provided at the small end portion, rod portion, and large end portion to reduce the weight of the connecting rod and to reduce the weight of the assembly type crankshaft. .

The invention according to claim 2 is characterized in that the connecting rod half is made of one material.
A recess for forming a hollow portion can be formed on one surface of the material.

The invention according to claim 3 is characterized in that oil holes for supplying oil from the large end portion to the spherical surface of the small end portion are respectively formed in the large end portion, the rod portion, and the small end portion. To do.
It is possible to supply oil to the spherical joint.

According to a fourth aspect of the present invention, in the connecting rod for an internal combustion engine according to any one of the first to third aspects, a spherical joint is constituted by a cup-shaped support portion having a small end portion formed on the back surface of the piston, The large end portion is connected to a crank pin having a hollow portion via a slide bearing, and a journal portion having a hollow portion and rotatably supported by a cylinder block is connected to the crank pin via an arm portion. It is characterized by.
The crankpin and the journal portion each having a hollow portion become lighter, and the crankshaft becomes lighter.

  In the invention according to claim 1, since the connecting rod is integrally connected as a whole, for example, the large end portion is compared with a two-part structure in which the rod portion and the connecting rod cap are coupled by bolts and nuts. In the present invention, the structure can be simplified, the number of parts can be reduced, and the connecting rod can be reduced in weight.

  In addition, since the spherical end constituting a spherical joint for connecting to the piston is provided at the small end, a conventional piston pin is not required, and the spherical surface on the piston side and the other end holding the small end If a member and a fastening member for fastening the holding member to the piston are provided, the piston itself and the connecting structure of the piston and the connecting rod can be reduced in weight.

  Furthermore, since the large end portion is an integral annular portion that fits into a separable crankpin that constitutes an assembly-type crankshaft, a hollow portion can be easily formed inside the divided crankpin. The crankshaft can be made lighter. Accordingly, the moment of inertia of the crankshaft can be reduced, the number of revolutions of the internal combustion engine can be increased, and the output of the internal combustion engine can be increased.

Furthermore , since the hollow portion is provided at the small end portion, the rod portion, and the large end portion, the connecting rod can be reduced in weight, and in addition to the weight reduction of the assembly type crankshaft, the main motion system parts of the internal combustion engine can be integrated. Thus, the weight can be reduced and the internal combustion engine can be rotated at a higher speed.

In the invention according to claim 2, since the connecting rod half is made of one material, it is possible to form a recess for forming a hollow portion on one surface of the material.

In the invention according to claim 3, since oil holes for supplying oil from the large end portion to the spherical surface at the small end portion are respectively formed inside the large end portion, the rod portion, and the small end portion, the spherical joint It is possible to supply oil.

In the invention which concerns on Claim 4, the connecting rod for internal combustion engines of any one of Claims 1-3 comprises a spherical joint with the cup-shaped support part by which the small end part was formed in the piston back surface, The large end is connected to a crank pin having a hollow portion via a slide bearing, and a journal portion having a hollow portion and rotatably supported by a cylinder block is connected to the crank pin via an arm portion. In addition, the crank pin and the journal portion each having a hollow portion become light, and the crank shaft becomes light.

The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. The drawings are viewed in the direction of the reference numerals.
FIG. 1 is a sectional view of an internal combustion engine incorporating a connecting rod according to the present invention. The internal combustion engine 10 includes a cylinder block 11, a piston 13 movably inserted into a cylinder bore 12 provided in the cylinder block 11, and the piston. The connecting rod 16 is connected to the lower portion of the cylinder block 11 and is supported by a hollow crankpin 17 so as to swing the connecting rod 16 in a swingable manner.

  The cylinder block 11 includes a cylinder portion 21 provided at an upper portion, a cylindrical sleeve 22 fitted inside the cylinder portion 21 and formed with a cylinder bore 12, and a skirt portion 23 attached to the lower portion of the cylinder portion 21. Become.

  Here, 31 is a sliding bearing interposed between the large end 25 of the connecting rod 16 and the crankpin 17, 32 is a counterweight provided on the crankshaft 18, and 33 is a head gasket (not shown) on the upper part of the cylinder block 11. ), A cylinder head 34, an intake valve 34, an exhaust valve 36, a combustion chamber 37, and a bolt 41... .. Are a plurality, the same applies hereinafter), and an underskirt portion 42 is an oil pan attached to the lower portion of the underskirt portion 38 with bolts 44.

  FIG. 2 is a cross-sectional view showing a connecting structure between a connecting rod and a crankshaft according to the present invention. The crankshaft 18 includes a first shaft 51 provided at an end, and bolts 52. It is an assembly-type thing provided with the attached 2nd shaft 53. FIG. Reference numeral 54 denotes a third shaft attached to the second shaft 53.

  The first shaft 51 is provided at a lower portion of the cylinder block 11 (see FIG. 1) and a journal portion 57 supported by the underskirt portion 38 (see FIG. 1) via a slide bearing 56, and an end portion of the journal portion 57. The arm portion 58 and the counterweight 32 extending in the radial direction from the arm portion 58 are provided, and a hollow portion 59 is provided inside the journal portion 57.

  The second shaft 53 includes an arm portion 61, a hollow crankpin 17 extending laterally from the arm portion 61, and a counterweight 32 extending radially outward from the arm portion 61. The hollow portion 62 is provided in the first shaft 51, and the end of the crank pin 17 is fitted in the recess 63 provided in the arm portion 58 of the first shaft 51, and the flange portion 53a protruding inward from the end of the crank pin 17 is provided in the first portion. It is attached to the arm portion 58 of the shaft 51. In addition, 31a and 31a are oil holes provided in the sliding bearing 31, and 64 is a hollow part provided in the journal portion 57 of the third shaft 54.

The connecting rod 16 is assembled to the crankshaft 18 according to the following procedure.
(1) The slide bearing 31 press-fitted into the large end portion 25 of the connecting rod 16 in advance is fitted to the crankpin 17.
(2) The recess 63 of the first shaft 51 is fitted into the end of the crankpin 17.
(3) The first shaft 51 is attached to the flange portion 53a with the bolt 52.
This completes the assembly of the connecting rod 16 to the crankshaft 18.

  FIG. 3 is a perspective view showing an assembled state of the piston, connecting rod and crankshaft according to the present invention, showing that the connecting rod 16 is swingably attached to the piston 13 and the connecting rod 16 is swingably attached to the crankshaft 18.

The piston 16 is, for example, a member manufactured by casting a material AC8A [JIS H 5202] and performing machining after performing T6 treatment as heat treatment.
The connecting rod 16 is preferably made of chrome steel, chrome molybdenum steel, or titanium alloy.

  FIG. 4 is an exploded perspective view showing the connecting structure of the connecting rod and the piston according to the present invention, and the spherical small end portion 66 of the connecting rod 16 is formed on the back side (details will be described later) of the crown portion 65 of the piston 13. A structure in which the upper part is applied and the lower part of the small end part 66 is held by a two-part holder 68 having concave spherical surfaces 67, 67, and the holder 68 is attached to the back side of the crown part 65 of the piston 13 with a nut member 71. Indicates. Reference numeral 69 denotes a spherical surface of the small end portion 66.

The connecting rod 16 includes the small end portion 66 described above, an annular large end portion 25, and a rod portion 73 that integrally connects the small end portion 66 and the large end portion 25.
The holder 68 includes two holder halves 68a and 68a. 68b and 68b are mating surfaces for joining the two holder halves 68a and 68a.
The holder 68 and the nut member 71 are members that constitute a part of the spherical joint 14.

  FIG. 5 is a cross-sectional view of the connecting rod and the piston according to the present invention. The piston 13 has a disc-shaped crown portion 65, and a cylindrical shape having a cylindrical shape extending downward from the edge of the crown portion 65 and having a thick wall. A lands 74 as a wall, a skirt 75, 75 as a cylindrical wall extending further downward from the land 74 and thinner than the land 74, and a small end 66 of the connecting rod 16 and sliding A cup-shaped support portion 78 as a spherical joint cup portion formed on the back surface 77 of the crown portion 65 in order to form a concave hemispherical surface 76 that can be freely fitted, and each of the land portion 74 and the cup-shaped support portion 78. And a rib 81... Which is extended downward from the back surface 77 of the crown 65.

The crown portion 65 includes a crown surface 83 that forms a part of the combustion chamber 37 (see FIG. 1).
The land portion 74 is a portion in which a top land 74a, a top ring groove 74b, a second land 74c, a second ring groove 74d, a third land 74e, and an oil ring groove 74f are provided on the edge of the crown portion 65 in this order from the crown surface 83 side. Yes, the top ring is fitted into the top ring groove 74b, the second ring is fitted into the second ring groove 74d, and the oil ring is fitted into the oil ring groove 74f.

The cup-shaped support portion 78 includes a downward recess 91 that opens downward, the concave hemispherical surface 76 formed on the bottom surface 92 of the downward recess 91, and a screw 94 that is formed on the inner peripheral surface 93 of the downward recess 91. And holding the small end portion 66 of the connecting rod 16 against the concave hemispherical surface 76 by the spherical surfaces 67 and 67 of the holder 68 inserted into the downward concave portion 91, and then supporting the male screw 95 provided on the nut member 71 in a cup shape. The connecting rod 16 is swingably attached to the piston 13 by being screwed into the female screw 94 of the portion 78.
The cup-shaped support portion 78, the holder 68, the nut member 71, and the small end portion 66 constitute the spherical joint 14 described above.

  The holder 68 is prevented from rotating with respect to the cup-shaped support portion 78 by a non-rotating pin (not shown), and is provided with a guide surface (not shown) to be brought into contact with the rod 73, whereby the piston 13 is moved with respect to the connecting rod 16. It is a member that prevents rotation.

The holder half body 68a includes a step portion 68c, and the holder half body 68a is fixed by applying the tip of the nut member 71 to the step portion 68c.
The nut member 71 includes the aforementioned male screw 95 and engagement recesses 71a for turning a tool on the outer peripheral surface of the end portion.

  The connecting rod 16 is provided with hollow portions 96, 97, 98, 99, 100... For weight reduction inside the large end portion 25 and the rod portion 73, and a light weight hollow portion inside the small end portion 66. 101 is a member provided with oil holes 103, 104, and 105 for supplying oil to the sliding surface of the spherical joint 14 from the mounting hole 102 side provided at the large end 25.

Next, a method for manufacturing the connecting rod 16 described above will be described.
6 (a) to 6 (c) are operation diagrams showing an example of a method for manufacturing a connecting rod according to the present invention.
In (a), two materials 111 (only one is shown in the figure) for preparing connecting rods are prepared.
Then, recesses 116, 117, 1118, 119, 120, 121 for making hollow portions 96, 97, 98, 99, 100, 101... (See FIG. 5) are cut by end mill 122 on one surface 112 of the material. To form.

  In (b), one surface 112 (see (a)) of each of the two materials 111 formed with the recesses 116, 117, 1118, 119, 120, 121 (see (a)) is combined, for example, wax Join by brazing or diffusion bonding.

  In (c), the two raw materials 111, 111 (see (b)) are cut by the end mill 124, and the small ends are polished to make the connecting rod 16.

  As another method for manufacturing the connecting rod 16, for example, the connecting rod halves divided into two in the thickness direction of the connecting rod are formed by casting, including the hollow portion, and the connecting rod halves are combined, as described above. It is manufactured by joining with brazing.

  As described above with reference to FIGS. 2 and 5, the present invention firstly includes the small end portion 66 connected to the piston 13, the large end portion 25 connected to the crankpin 17 of the crankshaft 18, and the small ends thereof. In the connecting rod 16 for an internal combustion engine that includes the rod portion 73 that connects the end portion 66 and the large end portion 25, the small end portion 66, the large end portion 25, and the rod portion 73 are integrally connected, and the small end portion 66 is connected to the small end portion 66. A spherical surface 69 constituting a spherical joint 14 for coupling to the piston 13 is provided, and the large end portion 25 is formed as an integral annular portion that fits into a split crank pin 17 constituting an assembled crankshaft 18. It is characterized by that.

  Since the connecting rod 16 is integrally connected as a whole, for example, compared with a structure in which the large end portion is divided into two parts in which the rod portion and the connecting rod cap are coupled with bolts and nuts, The number of parts can be simplified and the connecting rod 16 can be reduced in weight, and the cost and productivity of the connecting rod 16 can be reduced.

  Further, since the small end portion 66 includes a spherical surface 69 constituting the spherical joint 14 for coupling to the piston 13, for example, a structure in which two pin boss portions of the piston are coupled to the small end portion of the connecting rod via a piston pin. In contrast, in the present invention, the piston 13 side is symmetrical to the shape of the cup-shaped support portion 78, the holder 68 and the nut member 71, that is, the piston axis extending in the moving direction of the piston 13 through the center of the piston 13. By adopting an axially symmetric shape, the piston 13 itself and the connecting structure of the piston 13 and the connecting rod 16 can be reduced in weight.

  Furthermore, since the large end portion 25 is an integral annular portion that fits into the separable crankpin 17 constituting the assembled crankshaft 18, the hollow portion 62 can be easily formed inside the divided crankpin 17. The crankshaft 18 can be reduced in weight. Accordingly, the moment of inertia of the crankshaft 18 can be reduced, the internal combustion engine 10 (see FIG. 1) can be increased in speed, and the internal combustion engine 10 can be increased in output.

Secondly, the present invention is characterized in that the rod portion 73 and the large end portion 25 are provided with hollow portions 96 to 101.
Since the rod portion 73 and the large end portion 25 are provided with the hollow portions 96 to 101, the connecting rod 16 can be reduced in weight, and together with the weight reduction of the assembly-type crankshaft 18, the main motion system components (ie, the internal combustion engine 10). The piston 13, the connecting rod 16, the crankshaft 18, and the piston-connecting rod connecting structure) can be reduced in overall weight, and the internal combustion engine 10 can be further rotated.
Further, the hollow portion 62 can be easily formed inside the crankpin 17 in a state where the hollow crankpin 17 is separated, and the cost of the assembly-type crankshaft 18 can be suppressed.

  In the present invention, the hollow is provided inside the connecting rod. However, the present invention is not limited to this, and a concave portion may be formed on the outer surface of the connecting rod to reduce the weight.

  The connecting rod for an internal combustion engine of the present invention is suitable for two-wheeled vehicles and four-wheeled vehicles.

It is sectional drawing of the internal combustion engine incorporating the connecting rod which concerns on this invention. It is sectional drawing which shows the connection structure of the connecting rod which concerns on this invention, and a crankshaft. It is a perspective view which shows the assembly state of the piston which concerns on this invention, a connecting rod, and a crankshaft. It is a perspective view which shows the connection structure of the connecting rod which concerns on this invention, and a piston. It is sectional drawing of the connecting rod and piston which concern on this invention. It is an effect | action figure which shows an example of the manufacturing method of the connecting rod which concerns on this invention. It is sectional drawing which shows the connecting rod for conventional internal combustion engines.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine, 11 ... Cylinder block, 13 ... Piston, 14 ... Spherical joint, 16 ... Connecting rod, 17 ... Crankpin, 18 ... Crankshaft, 25 ... Large end part, 31 ... Sliding bearing, 57 ... Journal part, 58 , 61 ... arm part, 59 ... hollow part of journal part, 62 ... hollow part of crank pin, 66 ... small end part, 69 ... spherical surface, 73 ... rod part, 76 ... spherical surface (concave hemispherical surface) , 77 ... of piston Back surface, 78 ... cup-shaped support portion, 96-101 ... hollow portion, 103-105 ... oil hole, 111 ... material .

Claims (4)

In a connecting rod for an internal combustion engine comprising a small end connected to a piston, a large end connected to a crankpin of a crankshaft, and a rod part connecting the small end and the large end respectively.
The connecting rod state, and are not connecting rod halves pair of integrally molded divided in the thickness direction are joined,
Before SL small end is provided with a spherical surface constituting the spherical joint for coupling to the piston,
Before SL large end portion, Ri integral annular portion der to fit dividable said crank pin that constitutes the crankshaft and assembly type,
The small end, an internal combustion engine connecting rods, characterized in Rukoto provided with each of the large end and the rod section hollow portion. The connecting rod halves, internal combustion engine connecting rods according to claim 1, wherein that you have made in a single material. The oil hole for supplying oil from the large end to the spherical surface of the small end is formed in each of the large end, the rod, and the small end. A connecting rod for an internal combustion engine according to claim 1 or 2. The connecting rod for an internal combustion engine according to any one of claims 1 to 3, wherein the small end portion constitutes the spherical joint with a cup-shaped support portion formed on the back surface of the piston, and the large end portion is The crank pin having a hollow portion is connected to the crank pin via a slide bearing, and a journal portion having a hollow portion and rotatably supported by a cylinder block is connected to the crank pin via an arm portion. An internal combustion engine.

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