JP6481359B2 - Lubrication structure - Google Patents

Description

  The present invention relates to a connecting rod for connecting a piston and a crankshaft of an internal combustion engine and a lubricating structure thereof.

  The internal combustion engine transmits the reciprocating motion of the piston to the crankshaft by the connecting rod and outputs it as a rotational driving force. The small end of the connecting rod and the piston are connected by a piston pin. In order to smoothly reciprocate the piston, it is necessary to efficiently supply lubricating oil to the inner peripheral surface of the small end that slides with the piston pin to promote lubrication. Lubricating oil injected from the cylinder block and piston and lubricating oil scraped up by the crankshaft adhere to the outer peripheral surface of the small end portion of the connecting rod. There is a structure for supplying oil to the inner peripheral surface of the small end portion using such lubricating oil.

  In Patent Document 1, an oil reservoir is provided in the connecting rod, an oil hole communicating from the oil reservoir to the piston pin is formed, and a piston that supplies cooling oil supplied dropwise from the passage hole through the oil hole to the piston pin. A pin lubricating oil supply device is disclosed. Further, in Patent Document 2, piston cooling oil flowing down from the oil outlet passage and the guide end through the hollow portion is provided at two locations formed in the connecting rod corresponding to the oil outlet passage and the guide end, respectively. An oil supply device for a piston received by an oil hole is disclosed.

Japanese Utility Model Publication No. 56-49213 Japanese Utility Model Publication No. 4-30248

  However, in the lubricating oil supply device disclosed in Patent Document 1, an oil reservoir protruding from the outer peripheral surface is formed at the small end of the connecting rod. When such a shape is added to the outer peripheral surface, the weight of the small end portion is increased and NVH (Noise, Vibration, Harshness) is deteriorated. Furthermore, since the small end portion is large, the compression height of the piston is also large, and the weight of the piston is increased. Moreover, a new mold must be recreated.

  In addition, in the oil supply device disclosed in Patent Document 2, oil that has dropped onto a portion other than the oil hole does not reach the piston pin. Therefore, the piston pin cannot be refueled unless the specific timing at which the drop point of the piston cooling oil coincides with the oil hole.

  Therefore, the present invention provides a connecting rod that can be oiled to the inner peripheral surface of the small end portion over a wide crank angle, is small and lightweight, and does not require a new mold.

Lubrication structure of the present invention includes a small end having an outer peripheral surface and inner peripheral surface, on the outer circumferential surface has a length in the circumferential direction of the small end, and a recess extending from one end to the other end The connecting rod is connected to the recess at one end, and has a connecting rod formed with a through hole penetrating from the outer peripheral surface to the inner peripheral surface, and a piston connected to the connecting rod. Inside the piston, a cooling channel through which lubricating oil flows is formed in the circumferential direction of the piston. An injection hole is formed in the middle of the cooling channel. At the bottom dead center of the piston, the through hole is positioned to face the injection hole, and the other end of the recess is positioned closer to the distal end side of the small end portion than the one end.

At this time, the recess may be formed so as to be included in a region facing the injection hole while the piston decelerates toward the bottom dead center on the outer peripheral surface. Further, the recess may be formed in a region excluding the tip of the small end portion. Moreover, you may form in the upper surface of a small edge part. Moreover, you may form with a fixed depth from one end to the other end. When the through hole is formed near one end, the recess may be formed so as to become shallower from one end to the other end. Or the storage part which stores lubricating oil near the other end may be formed. Moreover, when the convex part extended in the circumferential direction of a small end part is formed in an outer peripheral surface, the recessed part may be formed in the convex part .

  According to the connecting rod of the present invention, the concave portion has a length in the circumferential direction, and lubricating oil adhering to the outer peripheral surface of the small end portion corresponding to a wide crank angle can be collected and guided to the through hole. Since the lubricating oil collected in the recess is additionally supplied, the amount of lubricating oil supplied from the through hole to the inner peripheral surface is increased. Furthermore, in the present invention, the through hole is formed at a position that is biased toward one end rather than the center of the recess. When the inertial force acts and the lubricating oil moves from the other end side to the one end side, the lubricating oil can be efficiently poured into the through hole. Moreover, in the present invention, since the concave portion is processed using the outer peripheral surface of the small end portion, the small end portion of the connecting rod and the piston can be formed small and light. Furthermore, it is not necessary to prepare a new mold for forming the recess.

  Further, if the concave portion is formed in a region excluding the tip of the small end portion, the mechanical strength of the tip portion where the load is most applied can be ensured. Moreover, if the recessed part is formed in the upper surface of a small end part, the lubricating oil collected in the recessed part can be poured into a through-hole by the inertial force which acts when a connecting rod raises.

  Further, when the concave portion has a certain depth, the concave portion can be easily formed by a machine tool or the like. If the concave portion is made shallower as it goes away from the through hole, the movement of the lubricating oil from the concave portion to the through hole can be promoted by the inertial force. If it is set as the recessed part in which the storage part was formed, the capacity | capacitance of the lubricating oil which can be received in a recessed part can be increased. Moreover, when it is not necessary to make an outer peripheral surface completely flat, a part of burr | flash formed along the division surface of an upper mold | type and a lower mold | type may remain as a convex part. If the concave portion is formed in the convex portion that is thicker than the other portion of the small end portion, the mechanical strength of the portion can be ensured even if the concave portion is formed. In addition, it is not necessary to prepare a new mold to form the convex portion.

  According to the lubricating structure of the present invention, the lubricating oil injected from the injection hole can be guided from the through hole to the inner peripheral surface of the small end portion, and lubrication of the inner peripheral surface can be promoted. In this lubricating structure, while the piston is decelerated toward the bottom dead center, the lubricating oil is injected into a region facing the injection hole. If such a region includes a recess, the lubricating oil can be collected in the recess more efficiently.

Sectional drawing which cut | disconnected the lubricating structure of 1st Embodiment in the surface perpendicular | vertical to a crankshaft. FIG. 2 is a cross-sectional view illustrating a small end portion of the connecting rod illustrated in FIG. The perspective view which looked at the piston shown by FIG. 1 from the back side. The schematic diagram which shows the position of the piston and connecting rod which started decelerating toward a bottom dead center. The schematic diagram which shows the position of the piston and connecting rod which moved to the bottom dead center. The enlarged view which shows the relationship between the position A and the position B, one end, and the other end. The expanded view of the outer peripheral surface which shows 1st Embodiment. Sectional drawing of the small end part which shows 1st Embodiment. The expanded view of the outer peripheral surface which shows 2nd Embodiment. Sectional drawing of the small end part which shows 2nd Embodiment. Sectional drawing of the small end part which shows the modification of 2nd Embodiment. The expanded view of the outer peripheral surface which shows 3rd Embodiment. Sectional drawing of the small edge part which shows 3rd Embodiment. Sectional drawing of the small end part which shows the modification of 3rd Embodiment. The perspective view of the connecting rod which shows 4th Embodiment.

  A connecting rod 11 and a lubricating structure 10 according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view of a lubricating structure 10 assembled to a cylinder block 2 of an internal combustion engine 1 cut in a vertical direction. FIG. 2 is a front view of the connecting rod 11.

  As shown in FIG. 1, the lubricating structure 10 includes a connecting rod 11 and a piston 12. As shown in FIG. 2, the connecting rod 11 has a concave portion 33 and a through hole 34 communicating with the concave portion 33 formed on the outer peripheral surface 31 of the small end portion 21. The recess 33 extends from the one end 35 to the other end 36 in the circumferential direction of the small end portion 21. The through hole 34 communicates with the recess 33 at one end 35.

  The concave portion 33 has a length in the circumferential direction of the small end portion 21 and can collect lubricating oil corresponding to a wide crank angle. The through hole 34 is arranged to be biased toward the one end 35, and the lubricating oil can be efficiently supplied by the one-way flow from the other end 36 toward the one end 35. Since the concave portion 33 is formed so as to be recessed from the surface of the outer peripheral surface 31, the small end portion 21 and the piston 12 of the connecting rod 11 can be formed in a small size and light weight, and the mold need not be remade. Each configuration will be described in detail.

  For convenience of description of the embodiment, the bottom dead center side is defined as “lower” and the opposite side from the bottom dead center side is defined as “up” based on the movement of the piston 12 assembled to the cylinder block 2. When the internal combustion engine 1 is disposed at an inclination, “upper” and “lower” do not necessarily coincide with the direction of gravity.

  As shown in FIG. 2, the connecting rod 11 is formed in a substantially rod shape, and includes a small end portion 21, a large end portion 22, and a rod portion 23. The small end portion 21 is formed at the tip of the connecting rod 11 and is formed in a cylindrical shape having an outer peripheral surface 31 and an inner peripheral surface 32.

  A concave portion 33 and a through hole 34 are formed in the outer peripheral surface 31. The recess 33 is formed to be recessed toward the inner peripheral surface 32 on the outer peripheral surface 31, and extends from one end 35 to the other end 36 along the circumferential direction of the small end portion 21. The through hole 34 penetrates from the outer peripheral surface 31 to the inner peripheral surface 32 and communicates with one end 35 of the recess 33. The shape of the recess 33 will be described in detail later.

  The large end portion 22 is formed at the proximal end of the connecting rod 11 and is formed in a cylindrical shape having a larger diameter than the small end portion 21. The rod portion 23 is formed in a substantially rod shape that connects the small end portion 21 and the large end portion 22. As shown in FIG. 1, the piston pin 15 is inserted into the small end portion 21 with a certain oil clearance and is connected to the piston 12. The large end portion 22 is connected to the crankshaft 13.

  As shown in FIG. 3, the piston 12 includes a crown portion 41, a pin boss 42, a skirt portion 43, a sidewall portion 44, and a cooling channel 47.

  As shown in FIG. 1, the crown portion 41 constitutes the combustion chamber 3 together with the cylinder bore 14 of the cylinder block 2. As shown in FIG. 3, a pair of pin bosses 42 are disposed opposite to each other on the back surface 46 of the crown portion 41 located on the side opposite to the combustion chamber 3. The pin bosses 42 are respectively formed with pin holes 45 on concentric axes. The skirt portion 43 extends from the outer peripheral edge of the crown portion 41 toward the side opposite to the combustion chamber 3. The sidewall portion 44 extends around the pin boss 42 and is continuous with the skirt portion 43.

  A hollow annular cooling channel 47 extending in the circumferential direction of the piston 12 is formed inside the crown portion 41. The cooling channel 47 has an oil inlet 48 and an oil outlet 49 that open to the back surface 46. The oil inlet 48 and the oil outlet 49 are disposed at a position separated by about 180 ° in the circumferential direction, that is, at a position symmetric with respect to the central axis of the piston 12.

  In the middle from the oil inlet 48 to the oil outlet 49, an injection hole 50 penetrating to the back surface 46 is opened. The injection hole 50 is disposed on the far side from the oil inlet 48 at two locations where the surface and the cooling channel 47 intersect when the piston 12 is divided into two equal parts by a surface perpendicular to the axis of the piston pin 15. In addition, the injection hole 50 may be arrange | positioned in the near side from the oil inlet 48 of the said 2 places.

  The lubricating structure 10 will be described in a state where the connecting rod 11 and the piston 12 are assembled to the cylinder block 2. As indicated by an arrow L in FIG. 1, lubricating oil is injected from an oil jet 16 provided in the cylinder block 2 toward an oil inlet 48. The lubricating oil introduced from the oil inlet 48 to the cooling channel 47 is divided into two clockwise and counterclockwise directions, flows through the cooling channel 47 and cools the piston 12.

  A part of the lubricating oil flowing through the cooling channel 47 is injected from the injection hole 50 toward the outer peripheral surface 31 of the small end portion 21 of the connecting rod 11. The remaining lubricating oil not injected from the injection hole 50 is discharged from the oil outlet 49 and falls into the crank chamber.

  The shape of the recess 33 will be described in more detail with reference to FIGS. FIG. 4 is a schematic diagram showing the movement of the piston 12 that has started to decelerate toward the bottom dead center. FIG. 5 is a schematic diagram showing the movement of the piston 12 moved to the bottom dead center. FIG. 6 is an enlarged view of the small end portion 21 showing each position in FIGS. 4 and 5.

  A position A shown in FIG. 4 is a position where the lubricating oil ejected from the injection hole 50 and the outer peripheral surface 31 intersect at a timing of 90 ° before the bottom dead center where the deceleration starts toward the bottom dead center. A position B shown in FIG. 5 is a position where the lubricating oil ejected from the injection hole 50 and the outer peripheral surface 31 intersect at the bottom dead center timing. As shown in FIG. 6, the other end 36 is arranged so as to be included in the region from the position A to the position B. One end 35 is disposed at position B. At this time, the one end 35 is positioned relatively below the other end 36.

  A position C shown in FIG. 2 is a position where the outer peripheral surface 31 intersects with a surface along the central axis of the small end portion 21 and the central axis of the large end portion 22. In the present specification, the tip of the small end portion 21 means the position C. A position D shown in FIG. 4 is a position where the surface H perpendicular to the central axis of the piston 12 intersects with the outer peripheral surface 31 along the central axis of the small end portion 21 at the timing when the vehicle starts decelerating toward bottom dead center. As shown in FIG. 5, the position C and the position D are arranged on the same side with respect to the surface H even at the timing of the bottom dead center.

  In this specification, the upper surface E means the outer peripheral surface 31 of the area | region from the position C to the position D, as shown in FIG. If the design of the position and angle of the injection hole 50 is changed, the arrangement of the position A and the position B can be variously changed. Regardless of how the position A and the position B are changed, the one end 35 and the other end 36 are preferably arranged so as to be included in the upper surface E.

  In the connecting rod 11 and the lubricating structure 10 of the present embodiment, the concave portion 33 has a length in the circumferential direction of the small end portion 21. Therefore, the lubricating oil adhering to the outer peripheral surface 31 corresponding to the wide crank angle shown in FIGS. 4 and 5 can be collected. Furthermore, since the lubricating oil collected in the recess 33 can be additionally supplied, the amount of lubricating oil supplied to the inner peripheral surface 32 can be increased.

  At the bottom dead center timing shown in FIG. 5, the small end portion 21 of the connecting rod 11 starts to move upward in conjunction with the crankshaft 13. On the other hand, the lubricating oil collected in the recess 33 continues to move downward due to inertial force. Therefore, the lubricating oil accumulated between the other end 36 and the one end 35 is relatively accelerated from the other end 36 toward the one end 35. Since the through hole 34 is formed at the end 35 where the lubricating oil cannot move, the lubricating oil can be efficiently poured into the through hole 34.

  And since the recessed part 33 is formed so that it may be depressed from the surface of the outer peripheral surface 31, the small end part 21 and piston 12 of the connecting rod 11 can be formed small and lightweight. Furthermore, it is not necessary to remake a mold to form the recess 33. Since the concave portion 33 has a constant depth, the concave portion 33 can be easily processed by a machine tool such as an end mill.

  Further, the recess 33 is arranged so as to be included in the upper surface E. That is, the concave portion 33 is formed in a region excluding the tip (position C) where the load is applied most at the small end portion 21. Therefore, even if the recess 33 is formed, the mechanical strength of the connecting rod 11 at the tip can be ensured.

  Further, the upper surface E on which the concave portion 33 is disposed is always above the surface H while the small end portion 21 swings in conjunction with the crankshaft 13. That is, on the upper surface E, the direction from the outer peripheral surface 31 toward the inner peripheral surface 32 is always downward with respect to the surface H. The through hole 34 is disposed on the lowermost side of the upper surface E.

  When the downward inertia force acts on the lubricating oil, the lubricating oil flows into the through hole 34 disposed at the destination. In the vicinity of the through hole 34, the inner peripheral surface 32 is relatively lower than the outer peripheral surface 31, so that the lubricating oil flows from the outer peripheral surface 31 toward the inner peripheral surface 32. As a result, the lubricating oil can be efficiently supplied to the inner peripheral surface 32 of the small end portion 21.

  Next, second to fourth embodiments and modifications thereof will be described. The second and third embodiments and modifications thereof are different from the first embodiment in the shape of the recess 33. The fourth embodiment is different from the first embodiment in the shape of the outer peripheral surface 31. Other configurations are the same as those in the first embodiment. Therefore, in the fourth embodiment to the fourth and modifications thereof, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  The second embodiment and its modification will be described with reference to FIGS. In the second embodiment and its modification, the recess 33 is formed so as to become shallower from the one end 35 toward the other end 36. Further, the recess 33 is formed narrower than the diameter of the through hole 34. The recess 33 may be formed so that the depth changes nonlinearly as shown in FIG. 10, that is, changes in an arc shape, or the depth changes linearly as shown in FIG. It may be formed. When such a recess 33 is formed, the movement of the lubricating oil from the other end 36 to the one end 35 can be promoted by an inertial force.

  Further, the third embodiment and its modification will be described with reference to FIGS. In the third embodiment, a storage portion 37 having a width in the direction along the central axis of the piston pin 15 is formed at a position biased toward the other end 36. The reservoir 37 may be formed at a certain depth as shown in FIG. 13, or may be formed as a spherical surface as shown in FIG. If the storage part 37 is formed, the capacity | capacitance of the lubricating oil which can be received in the recessed part 33 can be increased.

  Furthermore, a fourth embodiment of the present invention will be described with reference to FIG. When the connecting rod 11 is formed by forging, burrs are formed along the dividing surface of the upper die and the lower die. When finishing the outer peripheral surface 31 of the connecting rod 11, the burrs are removed by cutting or polishing. When it is not necessary to make the outer peripheral surface 31 completely flat, the burr may not be completely removed and may remain on the outer peripheral surface 31 as a convex portion 38 that rises in a thin band shape. By forming the concave portion 33 in the convex portion 38 that is slightly thicker than other portions of the small end portion 21, the mechanical strength can be secured even if the concave portion 33 is formed. In addition, it is not necessary to newly increase a mold or man-hours in order to form the convex portion 38.

  Each of the above-described embodiments can be variously modified without departing from the technical idea of the present invention. For example, the small end of the connecting rod may further include a bush such as copper. When the bush is provided, the through hole is formed so as to penetrate from the outer peripheral surface of the small end portion to the inner peripheral surface of the bush. In addition, the arrangement of the oil outlet may be changed to a position facing the recess, and the oil outlet may also function as an injection hole. You may comprise so that the lubricating oil scraped up by the crankshaft may adhere to the outer peripheral surface of a small end part.

  DESCRIPTION OF SYMBOLS 10 ... Lubrication structure, 11 ... Connecting rod, 12 ... Piston, 13 ... Crankshaft, 21 ... Small end part, 31 ... Outer peripheral surface, 32 ... Inner peripheral surface, 33 ... Recessed part, 34 ... Through-hole, 35 ... One end, 36 ... The other end, 37: storage part, 38: convex part, 47 ... cooling channel, 50 ... injection hole, E ... upper surface

Claims (8)

A small end portion having an outer peripheral surface and an inner peripheral surface, the outer peripheral surface having a length in the circumferential direction of the small end portion and extending from one end to the other end; the concave portion and the one end A connecting rod formed with a through hole that communicates with the inner peripheral surface from the outer peripheral surface ;
A piston connected to the connecting rod,
Inside the piston, a cooling channel through which lubricating oil flows is formed in the circumferential direction of the piston,
In the middle of the cooling channel, an injection hole is formed,
The lubricating structure characterized in that, at the bottom dead center of the piston, the through hole is positioned opposite to the injection hole, and the other end of the recess is positioned closer to the distal end side of the small end portion than the one end. . The recess, lubricating structure according to claim 1, characterized in that said piston in said outer peripheral surface is formed so as to be included in the injection hole facing the region during deceleration toward the bottom dead center . The recess, lubricating structure according to claim 1 or 2, characterized in that it is formed in a region excluding a distal end of the small end. The lubricating structure according to any one of claims 1 to 3, wherein the concave portion is formed on an upper surface of the small end portion. The lubricating structure according to any one of claims 1 to 4 , wherein the recess is formed at a certain depth from the one end to the other end. The lubricating structure according to any one of claims 1 to 4 , wherein the concave portion is formed so as to become shallower from the one end toward the other end. The lubricating structure according to any one of claims 1 to 4 , wherein the concave portion is formed with a reservoir for storing lubricating oil near the other end. A convex portion extending in the circumferential direction of the small end portion is formed on the outer peripheral surface,
The lubricating structure according to any one of claims 1 to 7 , wherein the concave portion is formed in the convex portion.

Images