JP5644853B2 - Engine oil passage structure - Google Patents

Description

  The present invention relates to an oil passage structure for an engine in a vehicle such as a motorcycle.

  In particular, in an engine that uses a belt-type continuously variable transmission as the transmission, when the cam chain is disposed on the transmission side with respect to the cylinder axis, the cam chain chamber is disposed between the belt chamber and the crank chamber. Since the cam chain requires oil lubrication, the oil that has lubricated the cam chain accumulates in the cam chain chamber. If oil remains in such a manner, mechanical loss (mechanical loss) occurs due to oil stirring by the cam chain, or oil mist increases, which is not preferable in terms of function. One of the reasons for the generation of oil mist is that it adversely affects the reducibility of blow-by gas.

  Therefore, it is necessary to discharge the oil accumulated in the cam chain chamber. In the engine described in Patent Document 1, the cam chain chamber is partitioned by a partition wall that supports the left bearing on the left side of the crank chamber surrounded by the left crankcase and the right crankcase. The cam chain chamber communicates with the crank chamber via a communication hole.

Japanese Patent No. 3184040

  The cam chain chamber is arranged between the belt chamber and the crank chamber as described above. However, in this type of engine, oil cannot be discharged to the belt chamber side where oil intrusion is strictly prohibited. It will be discharged to the crank chamber side arranged in. However, if a discharge hole or the like is provided on the crank chamber side, oil can be discharged while the engine is stopped. However, while the engine is running, wind pressure due to rotation of the crank (crank web) and air flow due to reciprocation of the piston The oil discharge efficiency is not always good.

  On the other hand, if the cam chain chamber is to be expanded to the oil pan side, not only the cam chain chamber but also the surrounding clutch cover mating surface may be enlarged, and further the oil pan volume may be compressed. In addition, it is substantially difficult to dispose the cam chain chamber directly in the width direction of the oil pan in view of the die cutting line at the time of die casting because of the mold configuration for engine production. For this reason, the oil must be discharged to the crank chamber side once, in which case the above-described problems are caused.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an oil passage structure for an engine that discharges oil appropriately and efficiently, and is effective for workability and compactness.

  An oil passage structure for an engine according to the present invention is an engine in which a cam chain for driving a valve operating cam is accommodated in a cam chain chamber formed by penetrating a cylinder assembly and a casing in the cylinder axial direction. An oil passage leading to the oil pan is arranged from the bottom.

In the engine oil passage structure of the present invention, the oil passage is formed obliquely toward the oil pan.
In the engine oil passage structure according to the present invention, a crankcase is attached to the casing, and an extension line of the oil passage is disposed so as not to intersect a mating surface of the casing with the crankcase. It is characterized by that.
In the engine oil passage structure according to the present invention, the casing is formed with a mating surface for attaching the clutch cover, and the extension line of the oil passage is arranged not to intersect the mating surface for attaching the clutch cover. It is characterized by being.

  According to the present invention, the oil accumulated in the cam chain chamber is directly discharged to the oil pan through the oil passage and is not affected by the rotation of the crankshaft or the reciprocating motion of the piston. As a result, oil can be returned to the oil pan very efficiently through the oil passage even when the engine is running, and both mechanical loss and oil mist can be effectively reduced. Since the generation of oil mist can be reduced, the oil content in the blow-by gas can be reduced and the blow-by gas reduction function can be improved. Along with this, it is possible to simplify the relationship with the reducing device, and in this respect also, it is possible to reduce the cost and the number of parts.

FIG. 1 is a side view showing the overall configuration of a motorcycle according to the present invention. FIG. 2 is a perspective view showing a configuration example of a body frame of the motorcycle according to the present invention. FIG. 3 is a side view showing a configuration example of a power unit mounted on a vehicle body frame in the motorcycle according to the present invention. FIG. 4 is a perspective view of a power unit in the motorcycle according to the present invention. FIG. 5 is a left side view showing an example of the casing of the power unit in the motorcycle according to the present invention. 6 is a cross-sectional view taken along line AA of FIG. 5 showing the internal structure of the casing according to the present invention. FIG. 7 is a right side view of the left case constituting the casing according to the present invention. FIG. 8 is a view taken in the direction of arrow B in FIG. FIG. 9 is a cross-sectional perspective view showing the periphery of the oil passage formed in the cam chain chamber in the casing according to the present invention. FIG. 10A is a side view showing around the opening of the oil passage on the cam chain chamber side in the casing according to the present invention. 10B is a view showing the periphery of the opening of the oil passage on the cam chain chamber side in the casing according to the present invention, and is a perspective view in the direction of arrow C in FIG. 10A. FIG. 11A is a side view showing around the opening of the oil passage on the oil pan side in the casing according to the present invention. FIG. 11B is a view showing around the opening of the oil passage on the oil pan side in the casing according to the present invention, and is a perspective view in the direction of arrow D in FIG. 11A.

Hereinafter, preferred embodiments of an oil passage structure for an engine according to the present invention will be described with reference to the drawings.
FIG. 1 is a side view of a motorcycle according to the present invention. First, the overall configuration of the motorcycle will be described with reference to FIG. In the drawings used in the following description, including FIG. 1, the front of the vehicle is indicated by an arrow Fr, the rear of the vehicle is indicated by an arrow Rr, and the lateral right side of the vehicle is indicated by an arrow R as necessary. The left side is indicated by an arrow L.

  The vehicle 100 is configured by forming a vehicle body skeleton by a plurality of vehicle body frames made of steel or aluminum alloy and mounting various parts on the vehicle body frame. Note that FIG. 2 is also referred to as an example of the configuration of the body frame. The down tube 101 which is a part of the body frame has a front end coupled to the steering head pipe 102 and extends substantially downward from the steering head pipe 102, and is connected to the under frame 103 near the lower end portion thereof. The under frame 103 extends substantially rearward. A rear frame 104 composed of a pair of left and right as a part of the vehicle body frame is coupled to the rear side of the down tube 101, and each of them extends generally inclining rearward and upward.

  The steering head pipe 102 rotatably supports a front fork 105. A handle bar 106 is fixed to the upper end of the front fork 105, and a front wheel 107 is rotatably supported on the lower end side. The front wheel 107 is equipped with a brake disc 108 that rotates integrally therewith.

  Further, referring also to FIG. 3, a bracket 109 for supporting the power unit 10 including the engine (internal combustion engine) 11 is attached to the rear end of the under frame 103, and a stay 110 provided on the bracket 109 is interposed therebetween. Thus, the swing type power unit 10 is supported around the swing shaft 111 so as to be swingable in the vertical direction. The power unit 10 is a unitization of a transmission assembly 14 that includes a cylinder assembly 12 of an engine 11, a crankcase 13, and a continuously variable transmission using a belt / pulley. The rear wheel 112 is rotatably supported by the transmission device 14 on the vehicle rear side. The axle side of the rear wheel 112 and the rear frame 104 are connected by a shock absorber 113, and the power unit 10 as a whole functions as a swing arm.

  Further, as shown in FIG. 1, a seat 114 for a rider to sit on is installed above the power unit 10, and a step board 115 on which the rider seated on the seat 114 places his feet above the underframe 103, It is supported by a step frame 116 (see FIG. 2). The step board 115 is formed integrally with a leg frame cover that constitutes the exterior of the vehicle. Further, between the power unit 10 and the seat 114, there is a luggage box 117 formed as a storage space for articles and the like opened and closed by the seat 114.

  As a vehicle exterior, various vehicle body covers are supported and attached to appropriate positions such as a vehicle body frame. The front leg shield 118 covers the front side of the vehicle and is mounted with a winker or the like, and is continuous with the above-described step board 115. The rear frame cover 119 covers the lower part of the seat 114 or the rear side of the vehicle, and a winker and a brake lamp are mounted. Upper portions of the front wheel 107 and the rear wheel 112 are covered with a front fender 120 and a rear fender 121, respectively.

  Next, the power unit 10 will be further described with reference to FIGS. 3 and 4. In the power unit 10, an air cleaner 15 is mounted on the upper surface side of the transmission 14 located on the vehicle rear side. The air cleaner 15 generally has a deformed box shape, and an air intake pipe 16 extends from the vicinity of the left front part, and an intake hose 17, a throttle body 18 and an intake pipe (intake pipe) 19 are sequentially provided from the front part toward the right side in front thereof. Connected. Here, the cylinder assembly 12 is formed by sequentially connecting a cylinder head cover 12A, a cylinder head 12B, and a cylinder 12C. The intake pipe 19 communicates with an intake port (intake port) in the cylinder head 12B of the cylinder assembly 12 and is cleaned from the air cleaner 15 to the intake port of the cylinder head 12B through an intake passage constituted by these members. Air is supplied. In addition, although detailed illustration is abbreviate | omitted, the fuel injection apparatus is standingly arranged by the intake pipe 19, and a fuel is injected toward an intake port. Further, an exhaust port is formed on the lower surface side of the cylinder assembly 12, and the exhaust pipe extends from the exhaust port to extend rearwardly and is connected to a muffler at the rear of the vehicle.

  As described above, the power unit 10 includes the cylinder assembly 12, the crankcase 13, and the transmission device 14, and these are integrated. With the power unit 10 mounted on the vehicle 100, the cylinder assembly 12, the crankcase 13, and the transmission device 14 are arranged in this order from the vehicle front side. The cylinder assembly 12 includes a single-cylinder air-cooled engine, and is arranged so that the cylinder axis is substantially horizontal along the vehicle longitudinal direction.

  Next, FIG. 5 is a left side view showing an example of a casing 20 that integrally constitutes a case for housing the crankcase 13 and the belts and pulleys of the transmission device 14, and further an oil pan and the like. Although a detailed illustration or the like is omitted on the front side of the casing 20, a crank chamber described later is configured in the crankcase 13, a crankshaft 21 is disposed in the crank chamber, and a cylinder is disposed at the front end. The assembly 12 is joined. In addition, a belt chamber 22 for accommodating the transmission device 14 is configured on the rear side of the casing 20, and an axle 122 of the rear wheel 112 is disposed in the belt chamber 22, and between the crankshaft 21 and the axle 122 is arranged. They are connected by a belt / pulley transmission 14.

  In the cylinder head 12B of the cylinder assembly 12, a camshaft (= valve cam) that constitutes a valve operating device for driving the intake and exhaust valves is disposed. A cam chain 23 is wound around a sprocket attached to each of the camshaft and the crankshaft 21, and the camshaft (= valve cam) is driven through the camchain 23 by the rotation of the crankshaft 21, and the intake / exhaust valves are operated. It comes to drive. As shown in FIG. 5, the cam chain 23 is arranged so as to be substantially horizontal along the longitudinal direction of the vehicle, although it is inclined substantially along the cylinder axis in a side view, i.e., slightly upward. As will be described later, a cam chain chamber for accommodating the cam chain 23 is formed in the casing 20, and this cam chain chamber is also arranged so as to be substantially horizontal along the vehicle longitudinal direction. As described above, since the cylinder axis is substantially horizontal along the vehicle longitudinal direction, the cam chain chamber 27 is formed through the cylinder assembly 12 and the casing 20 in the cylinder axis direction. A cam chain for driving a camshaft (= valve cam) is accommodated in the cam chain chamber 27.

  As shown in FIG. 6, the casing 20 is divided into left and right parts, and the left and right cases (the left case 20A and the right case 20B) are joined by their mating surfaces 20a. The inside of the casing 20 is divided into a plurality of chambers for each function, a crank chamber 24 is formed at the center in the left-right direction, and the crankshaft 21 is rotatably supported by left and right bearings 25 and 26. In the left case 20 </ b> A, a cam chain chamber 27 is formed on the left side of the crank chamber 24, and the cam chain 23 is accommodated in the cam chain chamber 27. A drive sprocket 28 is attached to the camshaft 21. The cam chain chamber 27 is hermetically sealed by a cam chain chamber lid 29, and a belt chamber 22 is further arranged on the left side of the cam chain chamber lid 29. Further, a mating surface 37 for attaching a clutch cover (not shown) is formed on the left case 20A.

  A crankcase 13 is provided in the right case 20B. The right case 20B (that is, the crankcase 13) is attached to the left case 20A. In the right case 20 </ b> B, an oil pump chamber 30 is formed on the right side of the crank chamber 24, and a lubricating oil pump is disposed in the oil pump chamber 30. An oil pan 31 is constituted by the left case 20A and the right case 20B at the lowermost portion of the casing 20. The oil pan 31 is located below the belt chamber 22, the crank chamber 24, the cam chain chamber 27, and the oil pump chamber 30.

  7 and 8 are a right side view and a front view of the left case 20A (single unit). As can be seen from these drawings, the oil pan 31 is located at the lowermost position of the left case 20A (casing 20), and is a chamber space isolated from the left cam chain chamber 27. The cam chain chamber 27 is basically a rectangular (cross section) chamber space as shown in FIG. 8, and the accommodated cam chain 23 travels in a direction substantially perpendicular to the paper surface of FIG. Yes.

  In the present invention, an oil passage that leads to the oil pan 31 is disposed particularly from the substantially lowermost portion of the cam chain chamber 27. As shown in FIG. 9, a peripheral wall 33 forming a cam chain chamber lid 29 rises leftward from the partition wall 32 of the crank chamber 24 and the cam chain chamber 27, and the cam chain chamber lid 29 is covered on the end surface of the peripheral wall 33. To wear. The oil passage 34 is obliquely formed so as to incline with respect to the crankshaft 21 from the immediate vicinity of the partition wall 32 toward the oil pan 31, and functions as a communication hole between the cam chain chamber 27 and the oil pan 31.

  10A and 10B show the opening 34a of the oil passage 34 on the cam chain chamber 27 side. As can be seen from the drawing, the opening 34a is formed at the substantially lowermost portion of the cam chain chamber 27 and communicates with the oil pan 31 side. 11A and 11B show the opening 34b of the oil passage 34 on the oil pan 31 side. As can be seen from the figure, the opening 34 b opens in the side wall 35 of the oil pan 31.

  The oil passage 34 is inclined as described above. In this case, as shown in FIG. 6, the mating surfaces of the extension line 36 of the oil passage 34 and the crankcase 13, that is, the left case 20 </ b> A and the right case 20 </ b> B of the casing 20. The mating surface 20a is arranged so as not to intersect. Further, the extension line 36 of the oil passage 34 is arranged so as not to intersect with the mating surface 37 of the left case 20A with the clutch cover (not shown).

  Now, when the engine is operating in the above configuration, the oil pump in the oil pump chamber 30 is operated, so that lubricating oil, that is, oil is supplied to the cylinder head 12B, the cam chain 23, etc., and the supplied oil is supplied to the cam chain chamber 27. Come back to. In the cam chain chamber 27, an oil passage 34 that is inclined with respect to the crankshaft 21 is provided from the lowermost portion toward the oil pan 31. The oil accumulated in the cam chain chamber 27 is directly discharged to the oil pan 31 through the oil passage 34 as indicated by an arrow P in FIG. In this case, since the cam chain chamber 27 is isolated from the crank chamber 24, the cam chain chamber 27 is not affected by the wind pressure caused by the rotation of the crankshaft 21 in the crank chamber 24 or the air flow caused by the reciprocating motion of the piston. Therefore, oil can be returned to the oil pan 31 through the oil passage 34 very efficiently even when the engine is operating. As a result, both mechanical loss and oil mist due to oil agitation of the cam chain 23 can be effectively reduced.

Also, since the oil passage 34 is provided, the oil in the cam chain chamber 27 can be discharged efficiently, so that even if the amount of oil passing through the cam chain chamber 27 increases, for example, there is no influence. That is, when the oil used for lubrication around the cylinder head is returned to the oil pan 31 via the cam chain chamber 27, this can be performed efficiently.
Furthermore, since generation | occurrence | production of oil mist can be reduced, the oil content in blow-by gas can be reduced and a blow-by gas reduction function can be improved. Along with this, it is possible to simplify the relationship with the reducing device, and in this respect also, it is possible to reduce the cost and the number of parts.

  The oil passage 34 is formed as a processing hole that connects the cam chain chamber 27 and the oil pan 31, and has a shape that can be processed from the oil pan 31 side or the cam chain chamber 27 side. That is, the extension line 36 of the oil passage 34 is in an arrangement relationship that does not intersect with the mating surface 20a (= crankcase mating surface) of the casing 20 and the mating surface 37 of the clutch cover. Since drilling or the like can be performed along the extended line 36, unnecessary processing that may occur on the processing axis when forming the oil passage 34 is abolished, and unnecessary processing holes are plugged or the like. It is no longer necessary to close with. Thereby, cost reduction and reduction of a number of parts can be aimed at.

As mentioned above, although this invention was demonstrated with various embodiment, this invention is not limited only to these embodiment, A change etc. are possible within the scope of the present invention.
For example, in addition to providing a single oil passage 34, it is also possible to provide two or more oil passages.

  According to the present invention, the oil accumulated in the cam chain chamber is directly discharged to the oil pan through the oil passage and is not affected by the rotation of the crankshaft or the reciprocating motion of the piston. As a result, oil can be returned to the oil pan very efficiently through the oil passage even when the engine is running, and both mechanical loss and oil mist can be effectively reduced. Since the generation of oil mist can be reduced, the oil content in the blow-by gas can be reduced and the blow-by gas reduction function can be improved. Along with this, it is possible to simplify the relationship with the reducing device, and in this respect also, it is possible to reduce the cost and the number of parts.

Claims (5)

In an engine in which a cam chain for driving a valve operating cam is accommodated in a cam chain chamber formed by penetrating a cylinder assembly and a casing in the cylinder axial direction.
The casing is configured by dividing the crankcase into left and right parts, and an oil passage leading to an oil pan is disposed from a substantially lowermost part of the cam chain chamber,
An oil passage structure for an engine, wherein an extension line of the oil passage is arranged so as not to intersect a mating surface of the crankcase in the casing.   The engine oil passage structure according to claim 1, wherein the oil passage is formed obliquely toward the oil pan. The casing is formed with a mating surface for attaching a clutch cover,
The engine oil passage structure according to claim 2, wherein an extension line of the oil passage is arranged so as not to intersect a mating surface to which the clutch cover is attached. In an engine in which a cam chain for driving a valve operating cam is accommodated in a cam chain chamber formed by penetrating a cylinder assembly and a casing in the cylinder axial direction.
In the casing, a mating surface for attaching a clutch cover is formed, and an oil passage leading to an oil pan is disposed from a substantially lowermost part of the cam chain chamber,
An oil passage structure for an engine, wherein an extension line of the oil passage is arranged so as not to intersect a mating surface to which the clutch cover is attached.   6. The engine oil passage structure according to claim 5, wherein the oil passage is formed obliquely toward the oil pan.

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