JP2013079623A - Oil jet structure of engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oil jet structure capable of sufficiently securing strength and rigidity of a cylinder block of an engine, without impairing castability of the cylinder block.SOLUTION: This oil jet structure includes a nozzle 91 for injecting an oil jet toward a back face of a piston P for reciprocating in a cylinder C of the engine E, a wall inside passage (a communicating passage 11 as one example) formed in a wall part 10 of the cylinder block 1 of the engine E and communicated with the nozzle 91, and a passage forming member (an oil distribution pipe 8 as one example) having an oil passage 80a communicated with the wall inside passage and fastened from the outside to the wall part 10.

Description

  The present invention relates to a structure of an oil jet for cooling a piston of an engine mounted on a vehicle such as a motorcycle, and more particularly to a structure of an oil passage communicating with a nozzle of the oil jet.

  In reciprocating engines with higher output than before, an oil jet is injected toward the back of the piston that reciprocates in the cylinder, and the top of the piston exposed to high-temperature combustion gas is effectively cooled. Yes. For example, in the engine described in Patent Document 1, a jet pipe (nozzle) is attached to each cylinder in communication with an oil gallery provided on the wall of the cylinder block, and oil is directed from the jet pipe toward the upper piston. It comes to inject.

Japanese Unexamined Patent Publication No. 60-6015

  By the way, when the oil passage for the oil jet is formed in the wall portion of the cylinder block as in the above-described conventional example, the wall portion must be formed thicker accordingly. It is not preferable. In other words, if the wall portion of the cylinder block is made thick overall in consideration of the dimensions of the oil passage, there is a risk that casting defects may occur due to that. However, if the wall is thickened only around the oil passage, there is a concern that the strength and rigidity of the block are locally reduced, causing problems of vibration and noise.

  In view of this point, an object of the present invention is to provide an oil jet structure that can sufficiently ensure the strength and rigidity of the cylinder block without impairing the castability of the cylinder block, and does not cause problems of vibration and noise. is there.

  In order to achieve the above object, an oil jet structure of an engine according to the present invention includes a nozzle that injects an oil jet toward the back of a piston that reciprocates in a cylinder, and a wall of a cylinder block. A passage-forming member having a communicating in-wall passage and an oil passage communicating with the in-wall passage, separate from the cylinder block, and fixed to the wall portion from the outside. Features.

  In the above configuration, since the oil passage is formed in the passage forming member that is externally attached to the wall portion of the cylinder block of the engine, the degree of freedom in dimensions and layout is increased compared with the case where it is formed in the wall portion of the cylinder block. The size of the oil passage can be freely set according to the specifications and the like.

  In addition, the passage forming member can be expected to increase the rigidity of the wall of the cylinder block, and the wall thickness can be reduced accordingly, so that it becomes difficult to form a cast hole during casting and the castability is improved. . Further, heat dissipation is higher than when the oil passage is formed in the wall portion of the cylinder block, and the temperature of the oil jet is lowered, which is advantageous for cooling the piston.

  When the engine includes a plurality of cylinders, the nozzle and the in-wall passage are provided for each cylinder, and the oil passage inside the passage forming member extends in the direction in which the plurality of cylinders are arranged. It is good also as a structure which arrange | positions in this way and connects the branch path branched for every cylinder from the said oil path to the channel | path in a wall for every said cylinder. In this case, the passage forming member is fixed to the wall portion of the cylinder block so as to extend in the direction in which the plurality of cylinders are arranged, so that the rigidity of the wall portion can be effectively increased.

  In this case, the passage forming member may be fixed to the wall portion of the cylinder block so as to be included in the range of the reciprocating motion in the reciprocating direction of the piston in the cylinder. By so doing, it is possible to ensure rigidity even if the wall portion of the cylinder block is curved so as to surround a plurality of cylinders and the thickness thereof is as thin as possible.

  The passage forming member may be fastened to a wall portion facing forward in the traveling direction when the engine is mounted on a vehicle and cooled by traveling wind. If it carries out like this, the thermal radiation of the oil which flows through the oil channel inside a channel | path formation member can be accelerated | stimulated, and it will become advantageous to cooling of a piston.

  Further, in an engine having a plurality of cylinders as described above, the in-wall passages respectively corresponding to the cylinders at both ends in the direction in which the plurality of cylinders are arranged are arranged in the direction in which the cylinders are arranged with respect to the center line of the corresponding cylinder. It may be formed by shifting inwardly.

  By doing so, the distance between the in-wall passages at both ends in the direction in which the cylinders are arranged is shortened, so that the length of the passage forming member can be shortened accordingly. This is advantageous in increasing the rigidity of the passage forming member and ensuring the sealing performance between the branch passage and the in-wall passage, and if the passage forming member is shortened, the space for installing it is small. There is also an advantage that it can be completed.

  Further, when the oil supply system of the engine includes an oil cooler for cooling the oil pumped from the oil pump, the flow of oil branched from the upstream side of the oil cooler is You may comprise so that it may supply to the oil path inside a formation member.

  In this way, as high pressure oil as possible can be supplied to the oil passage inside the passage forming member without being affected by the pressure loss of the oil cooler, and the oil jet injection pressure is increased to increase the cooling efficiency of the piston. be able to.

  As described above, in the engine oil jet structure according to the present invention, the passage for supplying oil to the nozzle of the oil jet is formed in a member separate from the cylinder block of the engine, and this member is formed on the wall of the cylinder block. Therefore, the strength and rigidity of the cylinder block can be secured without impairing the castability of the cylinder block, thereby preventing vibration and noise problems. In addition, heat dissipation is higher than when the oil passage is formed in the wall of the cylinder block, which is advantageous for cooling the piston by the oil jet.

It is a perspective view which shows the external appearance of the main body of the engine which concerns on embodiment of this invention. It is the front view seen from the front of the engine. It is the perspective view seen from the front diagonal upper right in the state which attached the oil distribution piping to the cylinder block of the engine. It is explanatory drawing which shows typically the whole structure of an oil supply system. It is sectional drawing, such as a crankcase, which shows the structure of the oil passage around an oil filter or an oil cooler. It is the top view which looked at the oil distribution pipe from the upper part. It is explanatory drawing which shows a part in cross section seeing oil distribution piping from the front. It is a figure which shows arrangement | positioning of a communicating path etc. seeing a cylinder block from the front. It is sectional drawing of the cylinder block which shows the structure which supplies oil to the nozzle of an oil jet through a communicating path from an oil distribution pipe. It is a perspective view which shows the structure of the oil jet for every cylinder by making a part into a cross section. It is a perspective view which shows a nozzle structural member independently.

  Hereinafter, an engine E according to an embodiment of the present invention will be described with reference to the drawings. The engine E of this embodiment is mounted on a motorcycle (not shown) as an example, and the concept of the front, rear, left, and right directions used in the following description is a rider riding on a motorcycle mounted with the engine E ( Based on the direction seen by the passenger.

-Overall configuration of the engine-
FIG. 1 is a perspective view showing the external appearance of the engine E when viewed from the diagonally upper front of the right side, and FIG. 2 is a view of the engine E viewed from the front. In these drawings, an exhaust manifold and a part of the cooling water hose are removed, and the engine body is mainly shown. As an example, the engine E is a parallel 4-cylinder gasoline engine in which four cylinders C (see FIG. 3) are arranged in a line in the left-right direction, and a cylinder head 2 is disposed above a cylinder block 1 in which the cylinders C are formed. It is assembled and the upper end of the cylinder C is closed.

  In a vehicle-mounted state, the cylinder block 1 and the cylinder head 2 of the engine E are slightly inclined forward so that the rear wall of the cylinder head 2 communicates with an intake port (not shown) for each cylinder C opened here. Thus, four throttle bodies 20 are arranged. A main throttle valve (not shown) is mechanically rotated in response to an operation of a throttle grip (not shown), and a sub-throttle valve (not shown) is rotated by the electric motor 21 so that the cylinder C Adjust the amount of air-fuel mixture to fill.

  On the other hand, as shown in FIG. 2, an exhaust port 22 communicating with each of the four cylinders C is opened forward on the front surface of the cylinder head 2. These four exhaust ports 22 are arranged in the left-right direction and open at substantially equal intervals, and are connected to upper ends of four exhaust pipes when an exhaust manifold (not shown) is attached. Each of the four exhaust pipes of the exhaust manifold extends downward in front of the engine E, then curves backward and gathers under the engine E, and is connected to a catalyst, an exhaust muffler, and the like.

  Further, the cylinder head 2 is provided with an intake valve and an exhaust valve for opening or closing the intake port and the exhaust port 22 with respect to each cylinder C as is well known, and a valve operating mechanism 23 for opening and closing these valves. (See FIG. 4) is, for example, a DOHC type with separate camshafts on the intake and exhaust sides. This valve operating mechanism 23 is mainly disposed at the upper part of the cylinder head 2, and a head cover 24 covers the upper part thereof. As shown in FIGS. 1 and 2, an ignition device 25 is provided for each cylinder C through the head cover 24.

  As shown in FIG. 3, the cylinder block 1 is an aluminum alloy low-pressure cast product, for example, and has a rectangular parallelepiped shape surrounding the four cylinders C, and a cam chain of the valve mechanism 23 is provided at the right end thereof. A receiving chain tunnel 1a is formed. An upper portion 4a (hereinafter referred to as an upper crankcase portion 4a) of the crankcase is integrally formed at the lower portion of the cylinder block 1, and a separate lower crankcase member 4b ( As shown in FIGS. 1 and 2, the crankcase 4 is configured.

  Further, an upper portion 5a (hereinafter referred to as an upper mission case portion 5a) and a lower portion 5b (see FIG. 5) of the transmission case 5 are integrally formed on the rear portions of the upper crankcase portion 4a and the lower crankcase member 4b, respectively. ) Are formed and assembled together to form the mission case 5. Although not shown, the transmission case 5 includes an input shaft and an output shaft, and houses a mechanical transmission 41 (see FIG. 4) that changes speed by switching meshing of a plurality of gears between the shafts.

  As shown on the left front side in FIG. 1, a clutch cover 50 is provided at the right end of the transmission case 5 to cover the main clutch that transmits / cuts off the driving force from the engine E to the transmission 41. A chain cover 51 is provided close to the front, and closes the opening on the right side at the bottom of the chain tunnel 1a. Further, a front balancer chamber 4c for accommodating one of the biaxial balancers is formed on the front surface of the crankcase 4 so as to bulge out.

  Further, as shown only in FIG. 3, a breather chamber 4 d for separating oil from blow-by gas and the other of the two-axis balancer from the rear surface of the cylinder block 1 to the upper crankcase portion 4 a and the upper transmission case portion 5 a. The rear balancer chamber 4e to be accommodated is formed integrally, and the upper opening is covered with a common lid member (not shown). 1 to 3, a separate oil distribution pipe 8 (passage forming member) is attached to the front wall 10 of the cylinder block 1, which will be described later.

  Returning to FIGS. 1 and 2, an oil pan 6 for storing lubricating oil is disposed below the crankcase 4. The oil pan 6 has a deep bottom portion 6a formed on the left side of the front half thereof, and the other portions are formed in a dish shape having a shallow bottom. And the cylindrical oil filter 61 for purifying oil is arrange | positioned so that it may protrude toward the front from the front part of the deep bottom part 6a of the oil pan 6. As shown in FIG. A cylindrical oil cooler 62 for cooling the oil is disposed above the oil filter 61 so as to protrude forward from the front portion of the crankcase 4.

-Oil supply system-
The engine E of this embodiment drives the oil pump 63 (refer FIG. 4, 5) with the pump drive gear provided in the input shaft of the transmission as an example, and the oil pumped up from the oil pan 6 by this oil pump 63 is used. An oil supply system 60 for distributing and supplying the various lubrication parts of the engine E such as the crankshaft 40 and the valve mechanism 23 is provided. 4 schematically shows the overall configuration of the oil supply system 60 of the engine E, and FIG. 5 shows oil passages around the oil filter 61 and the oil cooler 62.

  As shown in FIGS. 4 and 5, a primary oil filter 59 is interposed in the first oil passage 64 from the oil pan 6 to the suction port of the oil pump 63. A second oil passage 65 extends from the discharge port of the oil pump 63 to the inlet of the oil filter 61 (secondary oil filter), and the oil cooler 62 is interposed from the outlet of the oil filter 61. A third oil passage 66 is extended. In FIG. 5, the portion of the second oil passage 65 on the downstream side of the bent portion 65a and the portion of the third oil passage 66 on the upstream side of the bent portion 66a are oiled by passages not shown in the drawing. It communicates with the filter 61.

  As schematically shown in FIG. 4, the oil cooler 62 includes a meandering oil passage 62a communicating with the third oil passage 66, a housing 62b surrounding a pipe forming the meandering oil passage 62a, and a housing 62b. An inlet 62c for introducing the cooling water and a drain outlet 62d for draining the cooling water in the housing 62b are provided, and the oil passing through the meandering oil passage 62a is cooled by the cooling water circulating in the housing 62b. ing.

  That is, as shown in FIGS. 1 and 2, the housing 62b of the oil cooler 62 is cylindrical, and the lower end of the cooling water hose 52 is connected to the cooling water inlet 62c extending upward from the upper portion thereof. ing. The upper end of the hose 52 is connected to a water diversion port 53 a (shown only by a broken line in FIG. 1) of a cap 53 provided at the upper left corner of the front surface of the cylinder block 1. The cap 53 covers the cooling water inlet 1b (see FIG. 3) to the water jacket w (see FIG. 8) in the cylinder block 1, and the cooling water inlet 53b protrudes obliquely downward. Is provided.

  An upper end of a cooling water hose 54 is connected to the introduction port 53b, and a lower end of the hose 54 is connected to a discharge port of a water pump 55 (shown only in FIG. 2). The water pump 55 discharges cooling water sucked from a radiator (not shown) through an upstream hose (not shown), and this cooling water circulates in the hose 54 and enters the cylinder block from the intake port 1b covered with the cap 53. It flows into the water jacket w in 1.

  Further, a part of the cooling water is diverted to the diversion port 53a at the cap 53, flows down through the hose 52, and is introduced into the housing 62b of the oil cooler 62 from the introduction port 62c. Then, the cooling water circulating in the housing 62b and cooling the oil in the meandering oil passage 62a as described above is drained from the drain port 62d. As shown in FIG. 1, the hose 56 connected to the drain port 62d extends obliquely upward on the right side, then bends and extends substantially horizontally to the right side, and then curves upward to rise near the right edge of the engine body. And it extends forward and is connected to a radiator (not shown).

  In this way, the oil can be effectively cooled by guiding a part of the cooling water to the oil cooler 62 before being supplied to the water jacket w in the cylinder block 1. However, since the pressure loss in the meandering oil passage 62a is large, if the pressure of the oil flowing through the third oil passage 66 in front of the oil cooler 62 is about 500 kPa as an example, the pressure after passing through the oil cooler 62 is about 400 kPa. To drop.

  Thus, the third oil passage 66 on the downstream side of the oil cooler 62 in which the hydraulic pressure has decreased communicates with a large-diameter main passage 60 </ b> A formed in the cylinder block 1. When the oil pump 63 is driven as the engine E is operated, the oil in the oil pan 6 is pumped up to the oil pump 63 through the first oil passage 64 and sent to the oil filter 61 through the second oil passage 65. The oil purified by the oil filter 61 is sent to the oil cooler 62, cooled as described above, and then sent to the main passage 60A through the third oil passage 66.

  As shown in FIG. 5, the main passage 60 </ b> A extends in the longitudinal direction (a direction perpendicular to the drawing sheet) of the lower portion of the crankcase 4. Then, as shown in FIG. 4, a plurality of oil passages branch from the main passage 60 </ b> A to supply oil to various lubrication parts of the engine E and to supply oil to the transmission 41. First, the fourth oil passages 67 a to 67 c branched from a predetermined position in the middle of the main passage 60 </ b> A supply oil to, for example, the journal portion of the crankshaft 40 through the inside of the wall of the crankcase 4.

  Further, a fifth oil passage (not shown) communicating with the fourth oil passages 67a and 67c at both ends is formed inside the crankshaft 40, and part of the oil from the fourth oil passages 67a and 67c is transferred to the crankshaft. It supplies to the sliding part of 40 and a connecting rod big end part. Further, a sixth oil passage 68 extends from the main passage 60 </ b> A to the generator 42 through the wall portion of the crankcase 4, thereby supplying oil to the generator 42.

  A seventh oil passage 69 extends from the main passage 60 </ b> A through the inside of the wall of the crankcase 4. The seventh oil passage 69 extends upward in the wall portion of the crankcase 4 and extends to the upper portion of the cylinder head 2 through each wall portion of the cylinder block 1 and the cylinder head 2. The oil sent through the seventh oil passage 69 is supplied to the valve mechanism 23 and lubricates the camshaft and the like. A branch passage 69a that branches from the middle of the seventh oil passage 69 supplies oil to the hydraulic tensioner 43 of the cam chain.

-Structure of oil jet-
Further, in the present embodiment, the eighth oil passage 70 branches from the third oil passage 66 between the oil filter 61 and the oil cooler 62 (that is, from the upstream side of the oil cooler 62), and the four cylinders C Oil is supplied to the jet nozzles 91 of oil jets arranged corresponding to each of the above. As shown in FIGS. 1 and 2, the eighth oil passage 70 includes an oil conduit 7 that is externally attached along the front surface of the engine E from the crankcase 4 to the cylinder block 1, and an oil component connected to the oil conduit 7. It is comprised by the piping 8.

  The path of the oil conduit 7 starts from an upper part of the oil filter 61 on the front surface of the deep bottom portion 6a of the oil pan 6 and extends upward so as to wrap around the right side of the oil cooler 62 above the oil filter 61. Turn to the right near the height. Then, the water drained from the oil cooler 62 extends to the right side in parallel with the hose 56 that sends the coolant to the radiator, and then bends upward at the right edge of the crankcase 5 to extend upward. It is bent to the left at the approximate center of the direction and connected to the oil distribution pipe 8.

  The oil conduit 7 is mainly composed of a metal pipe 71 such as a steel pipe, but an elastic pipe 72 (for example, a polyester resin is laminated on a rubber hose) at a portion that is bent upward at the right edge of the crankcase 5. The pressure-resistant rubber pipe or the like) is connected via the coupling members 73 and 74, thereby absorbing the dimensional error and the mounting error and reducing the stress applied to the metal pipe 71. Here, the lower coupling member 73 is a rubber tube as an example, and is held by the clamp member 75. The clamp member 75 is integrally provided with an engaging portion (not shown) for supporting the cooling water hose 56. That is, the oil conduit 7 and the hose 56 that are close to each other are supported on the crankcase 4 by the clamp member 75.

  As shown in FIG. 5, one end portion 71 a of the metal pipe 71 that is the upstream end of the oil conduit 7 is bolted to the front surface of the deep bottom portion 6 a of the oil pan 6 by a joint 76. A branch path 66b that branches from the middle of the third oil passage 66 between the oil filter 61 and the oil cooler 62 and extends forward is formed on the front wall of the deep bottom portion 6a. The end portion 71 a of the metal pipe 71, that is, communicates with the upstream end of the oil conduit 7. That is, the oil flow branched from the third oil passage 66 is introduced into the upstream end of the oil conduit 7 on the upstream side of the oil cooler 62.

  On the other hand, as shown in FIGS. 1 and 2, at the downstream end of the oil conduit 7, the upper end portion 71 b of the metal pipe 71 bent to the left side is bolted to the right end portion of the oil distribution pipe 8 by a joint 77. The oil distribution pipe 8 is fastened to the front wall 10 of the cylinder block 1 and extends linearly in the left-right direction, and four exhaust pipes of an exhaust manifold (not shown) are positioned in front of the oil distribution pipe 8. In other words, the oil conduit 7 and the oil distribution pipe 8 are fastened to the wall portion facing forward when the engine E is mounted on the motorcycle, and are effective by the traveling wind passing between the exhaust pipes in front of the oil conduit 7 and the oil distribution pipe 8. To be cooled.

  In the present embodiment, as described above, the oil conduit 7 is connected to the right end of the oil distribution pipe 8 that extends to the left and right, and the left end of the oil distribution pipe 8 is closed. Therefore, as shown in FIG. There is no risk of interference between the cooling water hoses 52, 54, 55 routed on the left side and the oil conduit 7. Further, as in the case where the oil conduit 7 is connected to the left and right center of the oil distribution pipe 8, it is not necessary to form an opening not only at both ends of the oil distribution pipe 8, but also at the center portion. There is no worry of interfering with the front balancer chamber 4c.

  Further, in the present embodiment, as described above, the oil conduit 7 and the oil distribution pipe 8 are arranged on the front surface of the crankcase 4 from the crankcase 4 to the cylinder block 1, and they are arranged on the right side of the cylinder block 1 and the crankcase 4. There is no part protruding to the left. Therefore, even if the motorcycle is largely inclined and falls down, the oil conduit 7 and the oil distribution pipe 8 are difficult to contact the obstacle, which is advantageous in preventing the damage.

  Next, the structure from the oil distribution pipe 8 to the oil jet injection nozzle 91 will be described in detail with reference to FIGS. FIG. 6A shows the oil distribution pipe 8 alone as viewed from above, and FIG. 6B shows a part in cross section as viewed from the front. FIG. 7 shows the pedestal 12 and the like to which the oil distribution pipe 8 is fastened when the cylinder block 1 is viewed from the front. FIG. 8 shows an oil supply path from the oil distribution pipe 8 to the injection nozzle 91 via the communication path 11, and FIG. 9 shows the state of the oil jet injected toward the piston P.

  As shown in FIGS. 6A and 6B, the oil distribution pipe 8 is made of metal, for example, aluminum die-cast, and is arranged to extend linearly in the longitudinal direction (left and right direction) with a space in front of the cylinder block 1. A main pipe portion 80, four branch pipe portions 81 integrally formed so as to protrude vertically from the main pipe portion 80 toward the rear cylinder block 1, and extending along the branch pipe portions 81, respectively. And four fastening boss portions 82 formed with bolt insertion holes 82a. Further, four fins 83 are formed on the peripheral surface along the longitudinal direction of the main pipe portion 80, and the cross section is substantially X-shaped. The fin 83 increases the rigidity and heat dissipation of the oil distribution pipe 8.

  In FIG. 6B, the main pipe portion 80 of the oil distribution pipe 8 is formed with an oil passage 80a extending in the longitudinal direction, as shown in cross section on the left side in the left-right direction, and four branch passages 81a communicating with the oil passage 80a. Are formed inside the four branch pipe portions 81, respectively. The oil passage 80a is tapered so as to expand the diameter on both ends corresponding to the draft angle of the mold. A flange 84 to which the upper end 71b of the metal pipe 71 of the oil conduit 7 is attached is formed at one end of the main pipe 80 (the end located at the right end when attached to the cylinder block 1). The other end portion of the main pipe portion 80 is sealed with a plug 85.

  On the other hand, as shown in FIG. 6A, each of the four branch pipe portions 81 is formed with a single-stage, small-diameter portion (hereinafter, referred to as a small portion 81b) at each of the end portions. It is inserted into the communication passage 11 (intrawall passage) for each C. That is, as shown in FIG. 7, the front wall 10 of the cylinder block 1 is formed with four pedestal portions 12 protruding forward for each cylinder C, and the communication passage 11 is formed on the front surface of the pedestal portion 12. Is open. The front surface of the pedestal portion 12 has a bowl shape in which a large-diameter circle surrounding the opening of the communication passage 11 and a circle having a smaller diameter are connected to each other, and an oil distribution pipe 8 is fastened next to the opening of the communication passage 11. A bolt hole 13 into which a bolt 85 (see FIGS. 1 to 3) for fastening the boss 82 is screwed is opened.

  In the present embodiment, the front wall portion of the cylinder block 1 is curved along the outer periphery of each of the four cylinders C, and has four arcuate shapes that bulge outward (forward) corresponding to each cylinder C. The parts are lined up in the left-right direction. And the said base part 12 is provided in the part which bulges outward in circular arc shape for every cylinder C. As shown in FIG. As shown in FIG. 7, the pedestal portion 12 for each cylinder C is formed to be shifted from the center line X of the corresponding cylinder C in the left-right direction, which will be described later.

  Then, as shown in FIG. 8, when the small-diameter portion 81b at the tip of the branch pipe portion 81 of the oil distribution pipe 8 is inserted from the front into the opening of the communication passage 11 that opens to the front surface of the pedestal portion 12, FIG. Although not shown, the bolt hole 13 on the front surface of the pedestal portion 12 and the bolt insertion hole 82a (see FIG. 6B) of the fastening boss portion 82 of the oil distribution pipe 8 match each other, and the fastening boss portion is secured by the bolt 85 inserted therein. 82 is fastened to the base 12. In addition, the small diameter part 81b of the branch pipe part 81 inserted in the communicating path 11 is formed with a circumferential groove 81c that surrounds the outer periphery thereof, and an O-ring is mounted.

  Thus, the branch pipe portion 81 of the oil distribution pipe 8 is oil-tightly fitted into the communication passage 11 of the front wall 10 of the cylinder block 1, and the communication passage 11 is connected to the main pipe portion 80 via the branch passage 81 a in the branch pipe portion 81. The oil passage 80a communicates with the inner oil passage 80a. The communication path 11 is composed of a horizontal path drilled laterally toward the cylinder C and a vertical path drilled upward from the lower end of the front wall 10 of the cylinder block 1 facing the inside of the crankcase 4 as shown in the figure. When viewed in the direction in which the crankshaft 40 extends, it is generally L-shaped.

  As shown in FIG. 9 in addition to FIG. 8, an oil jet nozzle component 9 is attached to the lower end of the communication path 11. As shown in FIG. 10, the nozzle component 9 is composed of an annular member 90 that is flat up and down, and an injection nozzle 91 that protrudes laterally from the outer periphery and then extends upward. A banjo bolt 92 inserted into the through hole 90 a from below is screwed into the lower end of the communication path 11 to fasten the annular member 90 to the lower end of the front wall 10 of the cylinder block 1.

  As shown in FIG. 10, the annular member 90 of the nozzle component member 9 is formed with an extended portion 90 b extending to the outer peripheral side continuously to a circular portion surrounding the through hole 90 a, and is viewed in the vertical direction. It has an oval shape, and a pin 90c for positioning is disposed on the upper surface of the extended portion 90b. Although not shown, the pin 90 c is fitted into a recess formed in the vicinity of the communication path 11 on the lower end surface of the front wall 10 of the cylinder block 1. Thus, the direction of the injection nozzle 91 can be accurately set as described below.

  As shown in FIG. 8, the banjo bolt 92 is a so-called through-hole bolt, and a central hole 92a extending along the axial center of the shaft portion having a male screw formed on the outer periphery opens at the tip surface of the shaft portion. On the other hand, on the base end side of the shaft portion, a communication hole 92b that penetrates the shaft portion in the radial direction and communicates with the center hole 92a is formed. A circumferential groove 92c is formed around the outer periphery on the base end side of the shaft so that both ends of the communication hole 92b communicate with each other.

  When the banjo bolt 92 is inserted into the through hole 90a of the annular member 90 from below, the base end of the injection nozzle 91 that penetrates the peripheral wall of the annular member 90 in the radial direction is the periphery of the shaft portion 92 of the banjo bolt 92. It faces the groove 92c. Therefore, an annular space formed between the circumferential groove 92 c and the circumferential wall of the annular member 90 communicates with the nozzle inner passage 91 a that opens at the base end of the injection nozzle 91. In other words, the communication passage 11 communicates with the circumferential groove 92 c through the center hole 92 a and the communication hole 92 b of the shaft portion “a” of the banjo bolt 92, and further communicates with the passage 91 a in the injection nozzle 91.

  Thus, in the cylinder block 1, the in-nozzle passage 91 a of the injection nozzle 91 communicates with the communication passage 11 in the front wall 10 for each cylinder C, and the inside of the main pipe portion 80 through the four branch passages 81 a of the oil distribution pipe 8. To the common oil passage 80a. Therefore, as described above, the oil guided from the oil conduit 7 to the oil passage 80a of the oil distribution pipe 8 is substantially equally divided into four branch passages 81a and flows into the communication passage 11, and the injection nozzle for each cylinder C. 91.

  The injection nozzle 91 extends from the outer periphery of the annular member 90 toward the inside of the cylinder C and then curves upward, and the oil jet OJ is directed toward the back surface (lower surface) of the piston P as shown in FIG. Spray. As an example, the injection direction of the oil jet OJ is directed to the exhaust side at the top of the piston P (the exhaust side divided into the intake side and the exhaust side, which is the front side in the present embodiment). So that the nozzle passage 91a is formed by cutting.

  In addition, as shown in FIG. 8, in this embodiment, the injection nozzle 91 is slightly lower than that so as not to contact the lower end of the skirt of the piston P (shown in phantom line) located at the bottom dead center. Is arranged. On the other hand, in the front wall 10 of the cylinder block 1, the communication passage 11 is formed below the water jacket w surrounding the upper half of the cylinder C with a predetermined interval, and the oil component connected to the communication passage 11 is formed. The pipe 8 is located at substantially the same height as the piston P located at the bottom dead center, between the top surface (upper surface) of the piston P and the lower end of the skirt in the example of FIG.

  In other words, the oil distribution pipe 8 is fastened to the wall portion 10 of the cylinder block 1 so as to be included in the range in which the piston P reciprocates in the cylinder C in the vertical direction. Since the oil stored in the oil passage 80a flows into the injection nozzle 91 through the branch passage 81a and the communication passage 11, the weight of the oil increases the injection pressure.

  Further, as shown in FIG. 8, the nozzle passage 91a is narrower than the oil passage 80a in the oil distribution pipe 8, and is further restricted by the tip of the injection nozzle 91. Even if the momentum is strong, the oil flow rate in the oil passage 80a and the communication passage 11 is lowered, and the oil pressure in the oil passage 80a is maintained. Since the oil passage 80a straddling the four cylinders C has a sufficiently large volume, the oil passage 80a has a so-called pressure accumulation function, and variation in the injection pressure of the oil jet for each cylinder C is extremely small.

  By the way, although not shown in FIG. 9, the piston P is connected to the crankshaft 40 via a connecting rod for each cylinder C of the engine E, and the web or connecting rod of the crankshaft 40 interferes with the oil jet OJ. In order to avoid this, the nozzle component member 9 is disposed so as to be shifted in the longitudinal direction (left-right direction) of the crankshaft 40 with respect to the center line X of the cylinder C. For this reason, as described above, the communication passage 11 for supplying oil to the injection nozzle 91 is also formed so as to be shifted from the center to either the left or right for each cylinder C.

  That is, as shown in FIG. 7, two communication passages 11 at both ends of the four communication passages 11 opening on the front surface of the cylinder block 1 corresponding to the four cylinders C arranged in the left-right direction correspond to each other. The center line X of the cylinder C is shifted inward in the left-right direction. That is, the communication path 11 is opened at a position shifted to the left from the center line X of the cylinder C in the right end cylinder C and to the right in the cylinder C at the left end.

  More specifically, in the cylinder C at the right end, the nozzle forming member 9 is arranged on the left side with respect to the center line X of the cylinder C. Correspondingly, the communication path 11 also extends from the center line X of the cylinder C. Open to the left. On the other hand, in the three cylinders C excluding the rightmost cylinder C, the nozzle forming member 9 is arranged to be shifted to the right side with respect to the center line X of the cylinder C. Correspondingly, the communication path 11 is also in the center of the cylinder C. The opening is shifted from the line X to the right.

  For this reason, among the four cylinders C, the distance between the communication paths 11 at both ends corresponding to the cylinders C at the left and right ends is shortened, and the length of the oil distribution pipe 8 can be shortened accordingly. This contributes to the weight reduction and rigidity improvement of the oil distribution pipe 8 and is advantageous in securing the sealing performance between the four branch pipe portions 81 and the communication passage 11 of the cylinder block 1 into which the branch pipe parts 81 are fitted. . Further, if the oil distribution pipe 8 is shortened, the installation space is small, which is advantageous in preventing interference with the hose and auxiliary equipment around the engine body.

  However, when the communication passages 11 corresponding to the cylinders C at the left and right ends are shifted inward, the four communication passages 11 are arranged at different intervals in the left-right direction. That is, as shown in FIG. 7, in this embodiment, only the distance d1 between the communication path 11 corresponding to the rightmost cylinder C and the adjacent communication path 11 is the distance d2 between the other communication paths 11. If the fastening boss portions 82 are provided at the same intervals as those of the communication passages 11, the intervals between the bolts 85 inserted into the bolt insertion holes 82a of the fastening boss portions 82 become uneven. This causes variations in the fastening force of the oil distribution pipe 8 to the cylinder block 1, which is disadvantageous for improving the rigidity and ensuring the sealing performance.

  In this embodiment, as shown in FIG. 7, in this embodiment, the bolt hole 13 is moved outward in the left-right direction in the communication path 11 corresponding to the cylinder C at the right end (that is, rightward with respect to the communication path 11). The distance from the bolt hole 13 corresponding to the adjacent communication path 11 is widened. More specifically, the bolt hole 13 corresponding to the second communication path 11 from the right is shifted to the left side to further widen the space between the bolt hole 13 corresponding to the right end communication path 11 and the third ( The bolt hole 13 corresponding to the communication path 11 (second from the left) is arranged on the communication path 11 so that the centers thereof are substantially aligned, and the bolt hole 13 corresponding to the communication path 11 at the fourth, ie, left end, from the right is It is arranged inward (that is, closer to the right side) in the left-right direction.

  Accordingly, the four bolt holes 13 respectively corresponding to the four communication paths 11 arranged in the left-right direction are arranged at substantially the same distance d3 in the left-right direction, and the four bolts screwed into these bolt holes 13 are arranged. 85 fastens the oil distribution pipe 8 to the cylinder block 1 with a substantially uniform fastening force in the longitudinal direction. Therefore, the coupling rigidity and sealing performance of the oil distribution pipe 8 are also improved. Note that the four bolts arranged in the left-right direction are alternately divided above and below the oil distribution pipe 8 and arranged in a staggered manner, which also contributes to an improvement in coupling rigidity and sealing performance.

-Effect-
With the configuration described above, in the engine E of the present embodiment, when the crankshaft 40 rotates, the oil pump 63 is driven, and the oil pumped up from the oil pan 6 is sent to the main passage 60A via the oil filter 61 and the oil cooler 62. It is done. The oil in the main passage 60A is further sent to various lubricating parts of the engine E and also sent to the transmission 41 behind the engine E.

  On the other hand, part of the oil sent from the oil pump 63 through the oil filter 61 to the third oil passage 66 branches to the eighth oil passage 70 upstream from the oil cooler 62, and the oil jet to the piston P Used for. That is, it is sent to the oil jets 91 for each cylinder C via the oil conduit 7 and the oil distribution pipe 8 attached to the outside of the engine E, and is injected toward the back surface of the piston P. .

  In this way, the oil for the oil jet is supplied not through the cylinder block 1 of the engine E but through the oil conduit 7 and the oil distribution pipe 8 outside the cylinder block 1, so that the passage inside the cylinder block 1 etc. is used. This facilitates heat dissipation of the oil, which is advantageous for cooling the piston P. In particular, in the present embodiment, an oil conduit 7 and an oil distribution pipe 8 are disposed between the front wall 10 of the cylinder block 1 and the exhaust manifold, and heat is effectively radiated by the traveling wind passing between the front exhaust pipes. Is promoted.

  The oil conduit 7 guides the flow of oil branched from the upstream side of the oil cooler 62 to the oil distribution pipe 8, and is not affected by the pressure loss chamber of the oil cooler. Can be supplied to the jet nozzle 91 of the oil jet. Thereby, the injection pressure of the oil jet is increased and the cooling efficiency of the piston P is increased. In addition, since the oil conduit 7 and the oil filter 61 are both disposed in front of the engine E and the distance to the oil distribution pipe 8 is relatively short, the pressure loss in the path is also reduced, and the oil jet This is advantageous in increasing the injection pressure.

  Furthermore, since the oil distribution pipe 8 made of metal (in this embodiment, made of aluminum die cast) is disposed on the front wall 10 of the cylinder block 1 so as to extend in the longitudinal direction and fastened, the cylinder block 1 As such, it can be formed as thin as possible to reduce its weight, and its strength and rigidity can be sufficiently secured while improving its castability.

  In particular, in the present embodiment, the front wall 10 of the cylinder block 1 is formed such that four arc-shaped portions that are curved along the peripheral wall of the cylinder C are lined up by stealing surplus space between adjacent cylinders C. Yes. And the oil distribution pipe 8 is fastened to the thinned portion to increase its strength and rigidity. The oil distribution pipe 8 is disposed on the front wall 10 of the cylinder block 1 so as to be included in the reciprocating range of the piston P in the cylinder C, and the pedestal portion 12 that fastens the fastening boss portion 82 is disposed in front of the cylinder block 1. Since it forms in the part which bulges in circular arc shape in the wall 10 as mentioned above, useless thickness is unnecessary.

  Furthermore, since the eighth oil passage 70 is constituted by the separate oil conduit 7 and the oil distribution pipe 8 as described above, the size of the eighth oil passage 70 is larger than that formed in the engine E. In addition, since the degree of freedom in layout is increased, the size of the oil passage can be easily changed in accordance with the specifications of the engine E and the like.

  That is, in general, a cylinder block of an engine is commonly used for a plurality of types of engines having different displacements, and the basic specifications may not be changed over a long period of time, for example, 10 years or more. The higher the load or rotation of the engine, the greater the thermal load of the piston, and the higher the cooling performance by the oil jet. In response to this, the oil passage must be enlarged.

  However, from the viewpoint of promoting the reduction in size and weight of the engine, it is preferable that the thickness of the cylinder block is also a minimum that can ensure the requirements such as strength and rigidity. Even if an attempt is made to expand the oil passage in the cylinder block as the specification is changed, the strength and rigidity of the block are locally reduced, which may cause vibration and noise problems.

  With regard to this point, if the eighth oil passage 70 is constituted by the separate oil conduit 7 and the oil distribution pipe 8 as in this embodiment, the size can be easily changed in accordance with the specifications of the engine E and the like. it can.

-Other embodiments-
As mentioned above, although various embodiments of the present invention have been described, the oil jet structure of the engine according to the present invention is not limited to the above embodiments, and the configuration thereof is within the scope not departing from the gist of the present invention. Can be changed, added or deleted. For example, in the above-described embodiment, the eighth oil passage 70 for the oil jet is configured by the oil conduit 7 and the oil distribution pipe 8 which are separate from the cylinder block 1, and each is disposed on the front surface of the engine E. However, the oil conduit 7 may be disposed inside the engine E, for example, in the cylinder head 2 or the rank case 4. A part of the oil conduit 7 may be formed inside the cylinder block 1, the cylinder head 2, the crankcase 4, and the like.

  In the above-described embodiment, the upstream end of the oil conduit 7 is connected to the third oil passage 66 between the oil cooler 61 and the oil cooler 62 so that oil is taken out from the upstream side of the oil cooler 62. However, the present invention is not limited to this, and the oil may be taken out from the downstream side of the oil cooler 62.

  In the above-described embodiment, the oil distribution pipe 8 is fastened to the front wall 10 of the cylinder block 1, but the rear wall may be used instead of the front wall 10 of the cylinder block 1, and a method such as welding other than fastening is used. In this case, the oil distribution pipe 8 may be fixed. The cylinder block 1 is not limited to the low pressure casting method, and may be manufactured by a gravity casting method or may be die cast.

  The oil distribution pipe 8 is formed with four fins 83 extending in the longitudinal direction so that the cross section of the main pipe portion 80 is X-shaped, but less than four or five or more fins are formed. However, the present invention is not limited to the fins, and an uneven shape that increases the surface area may be formed on the peripheral surface of the main pipe portion 80.

  Furthermore, in the above-described embodiment, the parallel four-cylinder engine E is described as an example. However, the present invention is not limited to this, and for example, a single cylinder, two cylinders, or three cylinders may be used. Alternatively, a V-type engine may be used. In the above embodiment, the transmission-integrated engine E is shown. However, the transmission may not be an integral type, or may not be a transmission.

  Furthermore, as long as the oil jet structure according to the present invention is an engine, it can be applied not only to motorcycles but also to engines mounted on other vehicles such as rough terrain vehicles and personal watercraft (PWC). it can.

  As described above, the present invention can sufficiently ensure the strength and rigidity without impairing the castability of the cylinder block of the engine, and does not cause problems of vibration and noise. The piston can be effectively cooled by the oil jet. Therefore, the industrial applicability is high.

1 Cylinder block 10 Cylinder block front wall (wall facing forward in the running direction)
11 Communication passage in the front wall of the cylinder block (passage in the wall)
7 Oil conduit 8 Oil distribution pipe (passage component)
80a Oil passage 81a Branch passage 9 Nozzle component member 60 Oil supply system 61 Oil filter 62 Oil cooler 63 Oil pump 66 Third oil passage (passage upstream of the oil cooler)
C Cylinder E Engine OJ Oil jet P Piston X Centerline of cylinder

Claims (6)

A nozzle that injects an oil jet toward the back of a piston that reciprocates in the cylinder;
An in-wall passage formed in the wall of the cylinder block and in communication with the nozzle;
An oil jet structure for an engine, comprising: an oil passage that communicates with the in-wall passage, and a passage forming member that is separate from the cylinder block and is fixed to the wall portion from the outside. . The engine includes a plurality of cylinders, and each of the cylinders is provided with the nozzle and a passage in the wall.
An oil passage inside the passage forming member extends in a direction in which the plurality of cylinders are arranged, and a branch passage that branches from the oil passage for each cylinder communicates with an in-wall passage for each cylinder. The oil jet structure according to claim 1.   The said channel | path formation member is fixed to the wall part of the said cylinder block so that it may be contained in the range of the said reciprocation about the direction to which a piston reciprocates within the said cylinder. Oil jet structure.   The oil jet structure according to any one of claims 1 to 3, wherein the passage forming member is fixed to a wall portion facing forward in a traveling direction when the engine is mounted on a vehicle.   The in-wall passages respectively corresponding to the cylinders at both ends in the direction in which the plurality of cylinders are arranged are formed to be shifted inward in the direction in which the cylinders are arranged with respect to the center line of the corresponding cylinder. The oil jet structure described.   The engine oil supply system includes an oil cooler for cooling the oil pumped from the oil pump, and the oil flow branched from the upstream side of the oil cooler is an oil passage inside the passage forming member. The oil jet structure according to any one of claims 1 to 5, wherein

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