JP2017198282A - Crankshaft - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a crankshaft which is high in rigidity while being suppressed in the enlargement of a size to a radial direction.SOLUTION: A second crank arm A2 of a crankshaft has a second thrust face S2 which is salient from a face to which a first crank pin CP1 is connected, being a face orthogonal to a center axis JL of the crankshaft, and also being a side face of the second crank arm A2. The second thrust face S2 reaches a center axis CS2 of a second crank pin CP2 arranged at an opposite side with the second crank arm A2 having the second thrust face S2 sandwiched therebetween with respect to the first crank pin CP1 which is connected to the second thrust face S2.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a crankshaft.

  The crankshaft of an internal combustion engine includes a crank journal that is the center of rotation of the crankshaft, a crankpin that is provided at an eccentric position from the crank journal and to which a connecting rod is connected, and a crank arm that connects the crank journal and the crankpin. ing.

  In order to ensure the rigidity of the crankshaft, for example, when the crank arm is viewed from the shaft end side of the crankshaft, a pair of adjacent crank pins are partially overlapped with the crank arm interposed therebetween. It is known that a crank pin and a crank journal adjacent to each other with a crank arm interposed therebetween are configured to partially overlap (for example, Patent Document 1).

JP-A-6-28332

  The rigidity of the crankshaft increases as the outer diameter of the crankpin or crank journal is increased to widen the above-described overlap region. However, when the outer diameter of the crankpin or crank journal is increased, the outer shape of the crankshaft in the radial direction is increased, which may interfere with peripheral components. Therefore, the improvement in the rigidity of the crankshaft by expanding the overlap region as described above has a limit in that the rigidity is increased while suppressing an increase in the size of the crankshaft in the radial direction.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a crankshaft having high rigidity while suppressing increase in size in the radial direction.

  A crankshaft that solves the above problems includes a crankpin, a crank journal, and a crank arm. The crank arm has a thrust surface which is a surface to which the crank pin is connected and which is perpendicular to the central axis of the crankshaft and is raised from the side surface of the crank arm. When the thrust surface is viewed from the shaft end side of the crankshaft, the thrust surface is provided on the opposite side of the crank pin having the same thrust surface with respect to the crank pin connected to the thrust surface. It reaches the central axis of at least one of the central axis of the other crankpin and the central axis of the crank journal.

  According to this configuration, the thrust surface to which the crank pin is connected rises from the side surface of the crank arm. Therefore, the portion of the crank arm where the thrust surface is provided is thicker than the other portion where the thrust surface is not provided (the thickness of the crank arm in the direction of the center axis of the crankshaft). And has high rigidity. And, such a thrust surface is at least one of the center axis of another crank pin provided on the opposite side of the crank arm having the thrust surface with respect to the crank pin connected to the thrust surface and the center axis of the crank journal. The central axis of the is reached. Accordingly, the rigidity of the crank arm between the crank pin and the other crank pin and the rigidity of the crank arm between the crank pin and the crank journal are increased as compared with the case where the thrust surface does not reach the central axis. become.

  Further, since the thrust surface is a surface raised from the side surface of the crank arm, a step is generated on the outer edge of the thrust surface with respect to the side surface of the crank arm. Although stress concentration is likely to occur at a portion where such a step exists on the side surface of the crank arm, according to this configuration, the crank arm can be prevented from being deformed by increasing the rigidity of the crank arm. Therefore, the stress generated at such a step is reduced, and for example, the strength of the crankshaft is improved.

  And since the said thrust surface is provided in the side surface of the crank arm to which a crankpin is connected, even if it provides the said thrust surface so that it may reach even the above-mentioned center axis, the external shape in the radial direction of a crankshaft does not enlarge. .

  Therefore, according to this configuration, it is possible to obtain a crankshaft having high rigidity while suppressing an increase in size in the radial direction.

The side view which shows the structure of the crankshaft concerning one Embodiment. Sectional drawing along the AA line shown in FIG. Sectional drawing along the BB line shown in FIG. The enlarged view of the C section shown in FIG.

  Hereinafter, an embodiment embodying a crankshaft will be described with reference to FIGS. The crankshaft 1 of the present embodiment is a crankshaft used for an engine having a V-type 6 cylinder and a bank sandwich angle set to 60 degrees.

  As shown in FIG. 1, for example, a pulley for driving a timing belt, a fan belt, or the like is attached to the left shaft end 4 of the crankshaft 1. A flywheel for smoothing the rotation by averaging the shaft torque of the engine is mounted on the right shaft end 5 of the crankshaft 1 in the drawing.

  The crankshaft 1 is provided with four crank journals (hereinafter referred to as journals) that serve as the rotation center of the crankshaft 1. In the following description, the first journal counted from the shaft end 4 is referred to as a first journal J1, and the second journal counted from the shaft end 4 is referred to as a second journal J2. The third journal counted from the shaft end 4 is referred to as a third journal J3, and the fourth journal counted from the shaft end 4 is referred to as a fourth journal J4. These journals J1 to J4 have the same shaft diameter. The central axes of the journals J1 to J4 are coaxial, and hereinafter, the central axes of the journals J1 to J4 and the central axis of the crankshaft 1 are referred to as “central axes JL”.

  Between each of the journals J1 to J4, a crank pin provided at a position eccentric from each of the journals J1 to J4 and connected to a connecting rod is disposed. In the following, the first crankpin counted from the shaft end 4 is referred to as a first crankpin CP1, and the second crankpin counted from the shaft end 4 is referred to as a second crankpin CP2, and counted from the shaft end 4. The third crankpin is called a third crankpin CP3, and the fourth crankpin counted from the shaft end 4 is called a fourth crankpin CP4. The fifth crankpin counted from the shaft end 4 is called a fifth crankpin CP5, and the sixth crankpin counted from the shaft end 4 is called a sixth crankpin CP6. These crankpins CP1 to CP6 have the same shaft diameter.

  The three cylinders provided in the first bank of the V-type six-cylinder engine are referred to as the first cylinder, the third cylinder, and the fifth cylinder in the arrangement order, and the three cylinders provided in the second bank are the second cylinder and the fourth cylinder in the arrangement order. When referred to as a cylinder or a sixth cylinder, a connecting rod provided in the first cylinder of the engine is connected to the first crankpin CP1. A connecting rod provided in the second cylinder of the engine is connected to the second crankpin CP2, and a connecting rod provided in the third cylinder of the engine is connected to the third crankpin CP3. . Further, a connecting rod provided in the fourth cylinder of the engine is connected to the fourth crankpin CP4, and a connecting rod provided in the fifth cylinder of the engine is connected to the fifth crankpin CP5. . A connecting rod provided in the sixth cylinder of the engine is connected to the sixth crank pin CP6.

  In the rotation direction of the crankshaft 1, the arrangement phases of the first crankpin CP1, the third crankpin CP3, and the fifth crankpin CP5 are shifted by 120 degrees. Further, in the rotation direction of the crankshaft 1, the arrangement phases of the second crankpin CP2, the fourth crankpin CP4, and the sixth crankpin CP6 are also shifted by 120 degrees. In an engine in which the sandwich angle is set to 60 degrees, in order to cause the combustion of the air-fuel mixture every time the crankshaft 1 rotates 120 degrees, that is, to cause the combustion at equal intervals every 120 degrees, The arrangement phase of the second crankpin CP2 with respect to the arrangement phase of the pin CP1 is shifted by 60 degrees in the direction opposite to the rotation direction of the crankshaft 1.

  Each journal J1-J4 and each crankpin CP1-CP6 are connected by nine crank arms, respectively. In the following description, the first crank arm counted from the shaft end 4 is referred to as a first crank arm A1, the second crank arm counted from the shaft end 4 is referred to as a second crank arm A2, and counted from the shaft end 4. The third crank arm is called a third crank arm A3, and the fourth crank arm counted from the shaft end 4 is called a fourth crank arm A4. The fifth crank arm counted from the shaft end 4 is called a fifth crank arm A5, the sixth crank arm counted from the shaft end 4 is called a sixth crank arm A6, and the seventh crank arm counted from the shaft end 4 is seventh. This crank arm is called the seventh crank arm A7, and the eighth crank arm counted from the shaft end 4 is called the eighth crank arm A8. The ninth crank arm counted from the shaft end 4 is referred to as a ninth crank arm A9.

  The first journal J1 and the first crank pin CP1 are connected by a first crank arm A1. The first crankpin CP1 and the second crankpin CP2 are connected by a second crank arm A2. The second crankpin CP2 and the second journal J2 are connected by a third crank arm A3. The second journal J2 and the third crank pin CP3 are connected by a fourth crank arm A4. The third crankpin CP3 and the fourth crankpin CP4 are connected by a fifth crank arm A5. The fourth crankpin CP4 and the third journal J3 are connected by a sixth crank arm A6. The third journal J3 and the fifth crank pin CP5 are connected by a seventh crank arm A7. The fifth crankpin CP5 and the sixth crankpin CP6 are connected by an eighth crank arm A8. The sixth crank pin CP6 and the fourth journal J4 are connected by a ninth crank arm A9.

  The first crank arm A1, the second crank arm A2, the fifth crank arm A5, the eighth crank arm A8, and the ninth crank arm A9 are provided with counterweights CW (FIG. 1 shows the fifth crank arm A5). The counter weight CW other than the counter weight CW provided in FIG. The counterweight CW is a weight for balancing the rotational inertia force generated by the movement of the piston and the connecting rod. By providing such a counterweight, the load acting on each journal can be reduced.

  The side surfaces of the crank arms A1 to A9 (side surfaces perpendicular to the central axis JL in the crank arms) are surfaces to which the crank pins are connected and are orthogonal to the central axis JL of the crankshaft 1. A thrust surface that is raised from the side surface is provided.

  Hereinafter, the thrust surface to which one end of the first crank pin CP1 is connected in the first crank arm A1 is referred to as a first thrust surface S1, and the other end of the first crank pin CP1 is connected in the second crank arm A2. The above thrust surface is referred to as a second thrust surface S2.

  The thrust surface to which one end of the second crankpin CP2 is connected in the second crank arm A2 is referred to as a third thrust surface S3, and the other end of the second crankpin CP2 is connected to the third crank arm A3. The thrust surface is referred to as a fourth thrust surface S4.

  The thrust surface to which one end of the third crank pin CP3 is connected in the fourth crank arm A4 is referred to as a fifth thrust surface S5, and the other end of the third crank pin CP3 is connected to the fifth crank arm A5. The thrust surface is referred to as a sixth thrust surface S6.

  The thrust surface to which one end of the fourth crankpin CP4 is connected in the fifth crank arm A5 is referred to as a seventh thrust surface S7, and the other end of the fourth crankpin CP4 is connected to the sixth crank arm A6. The thrust surface is referred to as an eighth thrust surface S8.

  The thrust surface to which one end of the fifth crank pin CP5 is connected in the seventh crank arm A7 is referred to as a ninth thrust surface S9, and the other end of the fifth crank pin CP5 is connected to the eighth crank arm A8. The thrust surface is referred to as a tenth thrust surface S10.

  The thrust surface to which one end of the sixth crank pin CP6 is connected in the eighth crank arm A8 is referred to as an eleventh thrust surface S11, and the other end of the sixth crank pin CP6 is connected to the ninth crank arm A9. The thrust surface is referred to as a twelfth thrust surface S12.

  Incidentally, the above-described thrust surfaces S1 to S12 are formed when the crank pins CP1 to CP6 are formed by cutting the forged or cast crankshaft 1.

  When the thrust surface is viewed from the shaft end 4 side or the shaft end 5 side of the crankshaft 1, the thrust surface sandwiches a crank arm having the thrust surface with respect to a crank pin connected to the thrust surface. And at least one of the central axis of another crank pin provided on the opposite side and the central axis of the crank journal. A specific embodiment of such a thrust surface is shown in FIGS.

  As shown in FIG. 2, the second thrust surface S2 is opposite to the first crank pin CP1 connected to the second thrust surface S2 across the second crank arm A2 having the second thrust surface S2. The center axis CS2 of the provided second crank pin CP2 is reached. The second thrust surface S2 extends in a fan shape around the central axis CS1 of the first crankpin CP1, and the outer edge S2A of the second thrust surface S2 reaches the central axis CS2.

  Similarly to the second thrust surface S2, the third thrust surface S3, the sixth thrust surface S6, the seventh thrust surface S7, the tenth thrust surface S10, and the eleventh thrust surface S11 are also thrust surfaces. It reaches the central axis of another crank pin provided on the opposite side across the crank arm having the same thrust surface with respect to the connected crank pin.

  That is, the third thrust surface S3 is provided on the opposite side of the second crank pin CP2 connected to the third thrust surface S3 across the second crank arm A2 having the third thrust surface S3. It reaches the central axis CS1 of the crankpin CP1. The third thrust surface S3 extends in a fan shape centered on the central axis CS2 of the second crankpin CP2.

  Similarly, the sixth thrust surface S6 is provided on the opposite side of the third crank pin CP3 connected to the sixth thrust surface S6 across the fifth crank arm A5 having the sixth thrust surface S6. It reaches the central axis CS4 of the four crankpins CP4. The sixth thrust surface S6 extends in a fan shape centered on the central axis CS3 of the third crankpin CP3.

  Similarly, the seventh thrust surface S7 is provided on the opposite side of the fourth crank pin CP4 connected to the seventh thrust surface S7 across the fifth crank arm A5 having the seventh thrust surface S7. The center axis CS3 of the three crank pins CP3 is reached. The seventh thrust surface S7 extends in a fan shape centered on the central axis CS4 of the fourth crankpin CP4.

  Similarly, the tenth thrust surface S10 is provided on the opposite side of the fifth crank pin CP5 connected to the tenth thrust surface S10 across the eighth crank arm A8 having the tenth thrust surface S10. 6 crankpin CP6 has reached center axis CS6. The tenth thrust surface S10 extends in a fan shape centered on the central axis CS5 of the fifth crankpin CP5.

  Similarly, the eleventh thrust surface S11 is provided on the opposite side of the sixth crankpin CP6 connected to the eleventh thrust surface S11 across the eighth crank arm A8 having the eleventh thrust surface S11. The center axis CS5 of the 5 crankpin CP5 is reached. The eleventh thrust surface S11 extends in a fan shape centered on the central axis CS6 of the sixth crank pin CP6.

  As shown in FIG. 3, the fourth thrust surface S4 is opposite to the second crankpin CP2 connected to the fourth thrust surface S4 with the third crank arm A3 having the fourth thrust surface S4 interposed therebetween. It reaches the central axis JL of the provided second journal J2. The fourth thrust surface S4 extends in a fan shape around the center axis CS2 of the second crankpin CP2, and the outer edge S4A of the fourth thrust surface S4 reaches the center axis JL.

  Similarly to the fourth thrust surface S4, the first thrust surface S1, the fifth thrust surface S5, the eighth thrust surface S8, the ninth thrust surface S9, and the twelfth thrust surface S12 are also thrust surfaces. It reaches the central axis of the crank journal provided on the opposite side of the crank arm having the same thrust surface with respect to the connected crank pin.

  That is, the first thrust surface S1 is provided on the opposite side to the first crank pin CP1 connected to the first thrust surface S1 across the first crank arm A1 having the first thrust surface S1. It reaches the central axis JL of the journal J1. The first thrust surface S1 extends in a fan shape around the central axis CS1 of the first crankpin CP1.

  Similarly, the fifth thrust surface S5 is provided on the opposite side of the fourth crank arm A4 having the fifth thrust surface S5 with respect to the third crank pin CP3 connected to the fifth thrust surface S5. It has reached the central axis JL of 2 journals J2. The fifth thrust surface S5 and the central axis CS3 of the third crank pin CP3 are spread out in a fan shape.

  Similarly, the eighth thrust surface S8 is provided on the opposite side of the fourth crank pin CP4 connected to the eighth thrust surface S8 across the sixth crank arm A6 having the eighth thrust surface S8. It has reached the central axis JL of 3 journals J3. The eighth thrust surface S8 extends in a fan shape around the central axis CS4 of the fourth crank pin CP4.

  Similarly, the ninth thrust surface S9 is provided on the opposite side of the fifth crank pin CP5 connected to the ninth thrust surface S9 across the seventh crank arm A7 having the ninth thrust surface S9. It has reached the central axis JL of 3 journals J3. The ninth thrust surface S9 extends in a fan shape around the central axis CS5 of the fifth crankpin CP5.

  Similarly, the twelfth thrust surface S12 is provided on the opposite side of the sixth crank pin CP6 connected to the twelfth thrust surface S12 across the ninth crank arm A9 having the twelfth thrust surface S12. It reaches the central axis JL of 4 journals J4. The twelfth thrust surface S12 extends in a fan shape around the central axis CS6 of the sixth crank pin CP6.

According to the crankshaft 1 of this embodiment demonstrated above, the following effects can be obtained.
(1) FIG. 4 shows an enlarged view of the vicinity of the second thrust surface S2. As shown in FIG. 4, the second thrust surface S2 to which the first crank pin CP1 is connected is formed so as to rise from the side surface A2S of the second crank arm A2. Therefore, the portion of the second crank arm A2 where the second thrust surface S2 is provided is equal to the rising dimension T1 of the second crank arm compared to other portions where the second thrust surface S2 is not provided. The thickness of A2 (the thickness of the second crank arm A2 in the direction of the central axis JL of the crankshaft 1) is thick, and the rigidity is high.

  As shown in FIG. 2, the second thrust surface S2 has a second crank arm A2 having a second thrust surface S2 with respect to the first crank pin CP1 connected to the second thrust surface S2. It reaches even the central axis CS2 of the second crank pin CP2 provided on the opposite side of the sandwich. Therefore, as indicated by a two-dot chain line L1 in FIG. 2, compared with the case where the second thrust surface S2 does not reach the central axis CS2, the distance between the first crankpin CP1 and the second crankpin CP2 is increased. The rigidity of the second crank arm A2, particularly the bending rigidity, is increased.

  Similarly, as shown in FIG. 3, the fourth thrust surface S4 has a third crank arm A3 having a fourth thrust surface S4 with respect to the second crank pin CP2 connected to the fourth thrust surface S4. It reaches even the central axis JL of the second journal J2 provided on the opposite side across. Therefore, as indicated by a two-dot chain line L2 in FIG. 3, the second thrust pin S2 between the second crankpin CP2 and the second journal J2 is compared with the case where the fourth thrust surface S4 does not reach the central axis JL. The rigidity of the 3-crank arm A3, particularly the bending rigidity, is also increased.

  In addition, the effect of the second thrust surface S2 described above is the same in the third thrust surface S3, the sixth thrust surface S6, the seventh thrust surface S7, the tenth thrust surface S10, and the eleventh thrust surface S11. Is obtained in the same way. In addition, the above-described effects of the fourth thrust surface S4 are as follows in the first thrust surface S1, the fifth thrust surface S5, the eighth thrust surface S8, the ninth thrust surface S9, and the twelfth thrust surface S12. Is obtained in the same way. Accordingly, the rigidity is increased in all the crank arms A1 to A9.

  (2) Further, as shown in FIG. 4, since the second thrust surface S2 is a surface raised from the side surface A2S of the second crank arm A2, the second thrust surface is compared with the side surface A2S of the second crank arm A2. A step is formed on the outer edge S2A of the surface S2. Since stress concentration is likely to occur at a portion where such a step exists on the side surface A2S of the second crank arm A2, it is often the case that such a step portion is formed of a curved surface to suppress stress concentration. In this regard, in the present embodiment, the deformation of the second crank arm A2 can be suppressed by increasing the rigidity of the second crank arm A2. Therefore, the stress generated at such a step portion is further reduced, and for example, the strength of the crankshaft 1 is improved. In addition, such an effect can be similarly obtained in each of the crank arms A1 to A9 whose rigidity is improved by the above-described thrust surfaces S1 to S12.

  (3) Since the second thrust surface S2 is provided on the side surface A2S of the second crank arm A2 to which the first crankpin CP1 is connected, the second thrust surface S2 is formed so as to reach the central axis CS2 as described above. Even if provided, the outer shape in the radial direction of the crankshaft 1 is not increased. Therefore, it is possible to obtain the crankshaft 1 having high rigidity while suppressing the enlargement of the crankshaft 1 in the radial direction. In addition, such an effect can be obtained similarly in each said thrust surface S1-S12 provided in the side surface of each crank arm A1-A9.

In addition, the said embodiment can also be changed and implemented as follows.
-Although each thrust surface S1-S12 was formed in fan shape, you may form in another shape.
The second thrust surface S2, the third thrust surface S3, the sixth thrust surface S6, the seventh thrust surface S7, the tenth thrust surface S10, and the eleventh thrust surface S11 are center axes of the crank pin. It may not be reached. Even in this case, the effects of the first thrust surface S1, the fourth thrust surface S4, the fifth thrust surface S5, the eighth thrust surface S8, the ninth thrust surface S9, and the twelfth thrust surface S12 are obtained. be able to.

  The first thrust surface S1, the fourth thrust surface S4, the fifth thrust surface S5, the eighth thrust surface S8, the ninth thrust surface S9, and the twelfth thrust surface S12 are centered on the crank journal. It does not have to be reached. Even in this case, the effects of the second thrust surface S2, the third thrust surface S3, the sixth thrust surface S6, the seventh thrust surface S7, the tenth thrust surface S10, and the eleventh thrust surface S11 are obtained. Can be obtained.

  Each thrust surface S1 to S12 reaches the center axis of the crankpin and the center axis of the crank journal, but only a part of each thrust surface S1 to S12 is formed to reach such a center axis. May be.

  The crankshaft 1 was an engine crankshaft having 6 cylinders, a cylinder arrangement of V type, and a bank sandwich angle set to 60 degrees. It may be a crankshaft of an engine in which a cylinder arrangement or other sandwich angle is set.

  DESCRIPTION OF SYMBOLS 1 ... Crankshaft, 4 ... Shaft end, 5 ... Shaft end, A1 ... 1st crank arm, A2 ... 2nd crank arm, A3 ... 3rd crank arm, A4 ... 4th crank arm, A5 ... 5th crank arm, A6 ... 6th crank arm, A7 ... 7th crank arm, A8 ... 8th crank arm, A9 ... 9th crank arm, CW ... Counterweight, J1 ... 1st journal, J2 ... 2nd journal, J3 ... 3rd journal , J4 ... fourth journal, S1 ... first thrust surface, S2 ... second thrust surface, S3 ... third thrust surface, S4 ... fourth thrust surface, S5 ... fifth thrust surface, S6 ... sixth thrust surface, S7 ... 7th thrust surface, S8 ... 8th thrust surface, S9 ... 9th thrust surface, S10 ... 10th thrust surface, S11 ... 11th thrust surface, S12 ... 12th thrust surface, A S ... side surface, CP1 ... first crankpin, CP2 ... second crankpin, CP3 ... third crankpin, CP4 ... fourth crankpin, CP5 ... fifth crankpin, CP6 ... sixth crankpin, S2A ... outer edge, S4A ... Outer edge.

Claims (1)

A crankshaft comprising a crankpin, a crank journal, and a crank arm,
The crank arm has a thrust surface which is a surface to which the crank pin is connected and which is perpendicular to the central axis of the crank shaft and is raised from a side surface of the crank arm.
When the thrust surface is viewed from the shaft end side of the crankshaft, the thrust surface is provided on the opposite side of the crank pin connected to the thrust surface across a crank arm having the thrust surface. A crankshaft reaching at least one of the central axis of another crankpin and the central axis of the crank journal.

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