JP4437908B2 - Engine oil return structure - Google Patents

Description

  The present invention relates to an oil return structure to a crank chamber in an engine mounted on a vehicle such as a motorcycle.

In general, in a four-cycle engine, oil sucked up from an oil pan by driving an oil nozzle is supplied from a main gallery to lubricating parts such as a crankshaft and a camshaft of a cylinder head. Most of the oil after lubrication of the camshaft falls from a plurality of oil return holes 67 provided at the side end of the crankcase 64 as shown in FIG. Returned to pan 74. As shown in FIG. 8B, the oil return hole 67 is formed in a crankcase end wall 65 that has a crank bearing 66 and partitions the crank chamber 63 and the pulsar chamber 62 in the crankcase 64. The oil OL passes through the chain tunnel 61 that houses the camshaft drive chain 60 and falls into the pulsar chamber 62, then flows through the oil return hole 67 into the crank chamber 63, and the oil OL shown in FIG. Is returned to the oil pan 74 (see Patent Document 1).
Japanese Patent No. 3026489

  However, the oil return hole 67 needs to have a shape that ensures a sufficient flow rate of the oil OL while being provided in a narrow place avoiding the boss of the crankshaft 68 and the boss for the tightening bolt. As shown in FIG. 8, the shape of the pulsar cover 69 in the crankcase 64 shown in FIG. 8B extends downward due to the presence of the long oil return hole 67. Thus, the pulsar cover 69 has a large shape in the vertical direction.

  Further, since the oil OL that has passed through the oil return hole 67 from the pulsar chamber 62 hits the lower side surface of the crank web 71 and is stirred, the oil OL is difficult to smoothly flow into the crank chamber 63 and the oil by the crank web 71 OL stir resistance occurs, which becomes the engine load.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and it is possible to smoothly return the oil to the crank chamber so that the oil does not hit the crank web while reducing the vertical dimension of the pulsar cover. Its purpose is to provide a structure.

In order to achieve the above object, in the oil return structure for an engine according to the first configuration of the present invention, a chain tunnel that houses a chain for driving a camshaft is formed at a side end of the engine, and one end of the crankshaft is formed. the chain is a pulsar rotor for engine speed detecting located chain sprocket and an axially outer this spanned is mounted, the pulser rotor is housed in pulser chamber covered by the rotor cover, the The bottom surface of the pulsar chamber is located above the bottom surface of the crank chamber, and the oil in the chain tunnel is radiated in the radial direction of the crank web in the crank chamber to a crankcase end wall that partitions the lower end portion of the chain tunnel and the crank chamber. An oil return passage returning to the vicinity of the end is formed, and the oil return passage is formed in the end wall of the crankcase. A first return hole of vignetting the vertical direction, the provided on the crankcase end wall communicating with said crank chamber and the lower end of the first return hole, and a horizontal direction of the second return hole, The inlet of the oil return passage is opened at the lower end of the pulsar chamber, and the lower end of the outlet of the oil return passage is located below the lower end of the crank chamber web .

In this configuration, the oil that has passed through the oil return passage from the chain tunnel flows into the vicinity of the radial end of the crank web in the crank chamber, so that it smoothly flows into the crank chamber without almost hitting the side surface of the crank web. . Therefore, it is possible to eliminate the agitation resistance caused by the oil hitting the crank web from being applied to the crankshaft. In addition, since the oil return passage can be formed through the inside of the crankcase end wall, there is no restriction on the position of the mating surface of the pulsar cover, so the lower end of the pulsar cover can be set to an upper position than before. Thereby, the vertical dimension of the pulsar cover can be reduced (shortened). Furthermore, the oil return passage is arranged in a shape that allows the lower end of the first return hole extending in the vertical direction to communicate with the second return hole, and thus has an L-shaped cross section. The web can be smoothly guided toward the vicinity of the end in the radial direction of the web. In addition, the lower end of the first return hole in the oil return passage extends below the mating surface with the pulsar cover in the crankcase, and the second return hole extends from a position below the mating surface to the lower end of the first return hole. Since the shape can be communicated to reach the crank chamber, an oil return passage having a simple structure and not restricting the position of the mating surface can be obtained.

The second configuration of the present invention is different from the first configuration in the configuration of the oil return passage. The oil return passage of the second configuration is provided on the end wall of the crankcase, and the chain tunnel, the crank chamber, Are formed by inclined holes inclined with respect to the vertical direction. According to this configuration, since the oil return passage is formed by the inclined hole, the radial end of the oil in the chain tunnel is prevented from hitting the side surface of the crank web through the oil return passage inclined downward. Can be smoothly led to the vicinity of the portion. In addition, the oil return passage is a downwardly inclined hole extending from the chain tunnel through the crankcase end wall to the lower part of the crank chamber, so that the position of the mating surface with the pulsar cover in the crankcase is simple. An oil return passage that does not impose any restrictions on the pressure can be obtained.

The third configuration of the present invention is also different from the first configuration in the configuration of the oil return passage. The oil return passage of the third configuration enters the crankcase end wall from below and is connected to the chain tunnel. It is formed by a straight entry hole that communicates with the crank chamber. According to this configuration, since the oil return passage is formed by the straight entry hole that enters the crankcase end wall from below and communicates the chain tunnel with the crank chamber, the oil in the chain tunnel is returned to the oil return passage. While guiding downward through the passage, it can easily flow into the vicinity of the end in the radial direction so as not to hit the side surface of the crank web in the crank chamber. In addition, the oil return passage is formed by a straight entry hole that enters the crankcase end wall from the lower side perpendicular to the crankshaft, so it has a simple structure and restricts the mating surface with the pulsar cover in the crankcase. The oil return passage does not give

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, exemplary embodiments of the invention will be described with reference to the drawings. FIG. 1 is a right side view showing an engine constructed using the oil return structure of the first embodiment of the present invention. In this embodiment, a parallel 4-cycle engine E mounted on a motorcycle is illustrated. . The engine E is located on the lower front side with respect to the vehicle body frame FR and is supported by the vehicle body frame FR. A crankcase CR and a cylinder CY located on the front side F of the engine body 1 and a gear case GE located on the rear side form an engine case EC. One end surface of the gear case GE is covered with a clutch cover 30.

  The engine case EC is composed of a case upper C1 and a case lower C2 which are metal castings divided into upper and lower parts divided by a front-lowering dividing surface, and a cylinder head 11 is connected to the upper surface of the cylinder CY in the case upper C1. A cylinder head cover 12 that covers the valve operating chamber is mounted on the upper surface of the cylinder head 11. The cylinder CY has a forward inclined posture in which the axis A1 is orthogonal to the dividing surface M. An oil pan 13 is connected to the lower surface of the case lower C2. The engine case EC, the cylinder head 11, the cylinder head cover 12, and the oil pan 13 form the engine body 1. A filter cooler unit 25 comprising an oil filter 3 and an oil cooler 4 is attached to the front surface of the engine E via a mounting bracket 5. An exhaust pipe P is connected to each of the four exhaust ports 14 of the cylinder head 11.

  2 is a cross-sectional view taken along the line II-II in FIG. 1 and shows a right end portion of the engine E. FIG. In FIG. 2, the crankcase CR is provided with partition walls 9 that partition the crank chambers 8 of the four cylinders. Each partition wall 9 and both end walls 10 are divided by a dividing surface M so that the partition upper half 9 a and the partition lower half are separated. It is divided into a portion 9b and an end wall upper half 10a and an end wall lower half 10b. A two-part crank bearing 16 that rotatably supports the crankshaft 15 is formed on the dividing surface M between the partition wall 9 and the end wall 10. The crankshaft 15 has an axis A2 extending horizontally in the lateral direction (left-right direction) of the vehicle body, and four cylinders are also arranged in the lateral direction. A pulsar rotor 20 for detecting the engine speed is attached to the right end of the crankshaft 15, and the pulsar rotor 20 is covered with a pulsar cover 21 attached to one end of the crankcase CR.

  A cam shaft 17 for opening and closing an intake / exhaust valve (not shown) is rotatably supported on the cylinder head 11, and oil OL from a main gallery described later is camped on the cylinder CY and the cylinder head 11. Oil supply passages 18 and 19 for supplying the shaft 17 are formed. Sprockets 22 and 23 are fixed to the right end portions of the camshaft 17 and the crankshaft 15, and a drive chain 24 for the camshaft 17 is bridged between the sprockets 22 and 23. The chain 24 is accommodated in a chain tunnel 27 provided in the vertical direction along the right end sides of the cylinder head 11 and the cylinder CY. A pulsar chamber 28 that is formed at the lower end of the chain tunnel 27, that is, inward of the pulsar cover 21 and accommodates the pulsar rotor 20, and the crank chamber 8 are partitioned by a crankcase end wall 10.

  FIG. 3 is a right side view of the case lower C2 with the pulsar cover 21 removed, and therefore corresponds to FIG. In FIG. 3, in this case lower C2, the distance L1 from the dividing surface M with the case upper C1 to the lower end of the mating surface 31 with the pulsar cover 21 is set shorter than the conventional one. That is, the mating surface 31 with the pulsar cover 21 is formed in a small (short) shape in the vertical direction by the lower end being displaced upward.

  4 is a cross-sectional view taken along line IV-IV in FIG. In the figure, the oil in the pulsar chamber 28 is transferred to the crank web in the crank chamber 8 in the lower half 10b of the end wall 10 of the crankcase partitioning the pulsar chamber 28 and the crank chamber 8 which is the lower end of the chain tunnel 27. An oil return passage 33 for returning to the vicinity of the radial end portion of 38 is formed. The oil return passage 33 is provided in a horizontal direction parallel to the crankshaft axis A2 at a position below the lower end of the mating surface 31 and a first return hole 34 extending in the vertical direction with an upper end opened to the pulsar chamber 28. A second return hole 35 communicating the lower end of the first return hole 34 and the crank chamber 8 is provided. The outer end opening of the second return hole 35 is closed by the plug 32. The first return hole 34 is formed by machining with a drill, and the second return hole 35 penetrates from the outside below the mating surface 31 toward the vicinity of the radial end of the crank web 38 in the crank chamber 8. It is formed by casting. Thereby, the oil return passage 33 can be easily formed regardless of the L-shaped cross section.

  5 is a cross-sectional view taken along the line V-V in FIG. This figure shows a main gallery 39 provided in the crankcase CR for supplying oil OL to the crank bearing 16 and the like, and is branched from the main gallery 39 to a partition lower half 9b and an end wall lower half 10b. A plurality of (five in this embodiment) journal oil supply passages 40A to 40E are formed. Both end portions 39a of the main gallery 39 are inclined upward and outward. In accordance with the inclination of the main gallery 39, the left and right ends C2a at the lower part of the case lower C2 are also inclined upward and outward. The outer ends of both end portions 39 a of the main gallery 39 are open to the pulsar chamber 28, and the openings are closed by plugs 42.

  Thus, by inclining both end portions 39a of the main gallery 39 and the lower end portions C2a of the case lower C2, the lower portion of the case lower C2 is formed in a horizontal straight line as shown by a two-dot chain line C2b. Thus, the lower corner C2b of the case lower C2 is eliminated. As a result, the bank angle θ with respect to the road surface S of the vehicle body can be increased. In other words, when the same required vehicle body bank angle θ as in the prior art is secured, the engine E can be arranged below the conventional one to achieve a low center of gravity of the motorcycle.

  In the above configuration, the oil OL accumulated in the oil pan 13 shown in FIG. 1 is sucked up by the oil pump 36 driven by the crankshaft 15, filtered and cooled in the oil filter cooler unit 25, Introduced to the gallery 39. The oil OL is further introduced into the journal oil supply passages 40A to 40E from the main gallery 39 shown in FIG. 5 and supplied to the crank bearing 16, whereby the crank bearing 16 is lubricated. The oil OL is further supplied from the journal oil supply passage 40A at the right end through the oil supply passages 18 and 19 shown in FIG. 2 to the cam shaft 17 in the cylinder head 11 to lubricate the cam bearing. Most of the oil OL supplied to the cylinder head 11 falls into the pulsar chamber 28 through the chain tunnel 27. The oil OL in the pulsar chamber 28 passes through the second return hole 35 from the first return hole 34 in the oil return passage 33 shown in FIG. 4 and is located near the radial end of the crank web 38 in the crank chamber 8. And then returns to the oil pan 13.

  In this oil return structure, the oil OL that has passed through the oil return passage 33 from the pulsar chamber 28 at the lower end of the chain tunnel 27 hardly hits the side surface of the crank web 38, and the radial direction of the crank web 38 in the crank chamber 8 is achieved. Smoothly flows near the end. Therefore, the oil OL can be circulated efficiently, and the stirring resistance caused by the oil OL hitting the crank web 38 does not become a load on the crankshaft 15. Moreover, since the oil return passage 33 has a simple structure in which two orthogonal first return holes 34 and second return holes 35 are provided in the crankcase CR, the oil return passage 33 can be easily formed.

  In the oil return structure, the lower end of the first return hole 34 in the oil return passage 33 extends to a position below the mating surface 31 with the pulsar cover 21 in the crankcase CR, and the second return hole 35 is extended to the mating surface. The oil return passage 33 does not constrain the position of the mating surface 31 because it has a shape that communicates from the lower part of 31 to the lower end of the first return hole 34 and extends into the crank chamber 8. Therefore, the mating surface 31 can be shaped so that the oil return passage 33 does not need to be arranged, so that the lower end thereof can be set at an upper position than the conventional one. The dimensions of can be made smaller (shorter).

  6 is a cross-sectional view showing a portion corresponding to FIG. 4 in the oil return structure according to the second embodiment of the present invention. In FIG. 6, the same or corresponding parts as those in FIG. The duplicated explanation is omitted. In this embodiment, the oil return passage 33A is formed by an inclined hole that penetrates the inside of the crankcase end wall 10b diagonally downward from the pulsar chamber 28 at the lower end of the chain tunnel 27 and communicates with the lower portion of the crank chamber 8. Is formed.

  Also in the oil return structure of this embodiment, the same effect as described in the above embodiment can be obtained. That is, since the oil return passage 33A is formed by an inclined hole, the vicinity of the radial end of the crank web 28 in the crank chamber 8 via the oil return passage 33A in which the oil OL in the pulsar chamber 28 is inclined downward. Therefore, the oil OL flowing into the crank chamber 8 can be circulated efficiently with almost no contact with the side surface of the crank web 38, and the oil OL hits the crank web 38. The stirring resistance does not become a load on the crankshaft 15. Further, since the oil return passage 33A does not restrict the position of the mating surface 31, the mating surface 31 with the pulsar cover 21 in the crankcase CR can be formed without paying attention to the arrangement position of the oil return passage 33A. The portion can be set at an upper position than before, and thereby the vertical dimension of the pulsar cover 21 can be reduced (shortened).

  Further, in the oil return structure, in addition to the above effects, the crankcase end wall 10 can be formed by a single machining process using a drill, and the plug 32 of FIG. The number of points and the number of manufacturing steps can be reduced, and the cost can be reduced accordingly.

  FIG. 7A is a cross-sectional view showing a portion corresponding to FIG. 4 in the oil return structure according to the third embodiment of the present invention. In FIG. In addition, overlapping explanation is omitted. In this embodiment, the oil return passage 33B is formed by an entry hole that enters the lower half 10b of the crankcase end wall 10 from below and communicates the pulsar chamber 28 at the lower end of the chain tunnel 27 and the crank chamber 8. ing. A screw portion 47 is formed below the entry hole, and a lower end opening of the entry hole is closed by a plug bolt 43 screwed into the screw portion 47.

  The oil return passage 33B is formed by the following procedure. That is, as shown in FIG. 7B, after producing the case lower C2 having the lower half portion 10b of the crankcase end wall that partitions the pulsar chamber 28 and the crank chamber 8 as shown in FIG. An entrance hole is formed by allowing the drill 44 to enter the crankcase end wall lower half 10b from below or by casting. Further, a threaded portion 47 is formed in the lower portion of the entry hole, and the plug bolt 43 shown in FIG. 7A is screwed to form an oil return passage 33B.

  Also in the oil return structure of the third embodiment, as described in the first embodiment, the oil OL flowing into the crank chamber 8 of FIG. And the agitation resistance caused by the oil OL hitting the crank web 38 does not become a load on the crankshaft 15. Furthermore, since the oil return passage 33B does not restrict the position of the mating surface 31, the vertical dimension of the pulsar cover 21 can be reduced by setting the lower end portion of the mating surface 31 to a position higher than the conventional one. Further, the oil return passage 33B requires a plug bolt 43 separately as compared with the second embodiment, but the drill 44 of FIG. 7C is inserted in a direction perpendicular to the dividing surface M from the bottom surface of the case lower C2. Since it can form by making it approach, formation of the oil return channel | path 33B is very easy. Also, when a cast pin is used instead of the drill 44, the oil return passage 33B can be easily formed.

It is a right view which shows the engine using the oil return structure of 1st Embodiment of this invention. It is the II-II sectional view taken on the line of FIG. It is a right view of the state which removed the cover part and pulsar cover of the case lower in the engine same as the above. It is the IV-IV sectional view taken on the line of FIG. FIG. 5 is a cross-sectional view taken along line V-V in FIG. 3. It is sectional drawing of the principal part of the oil return structure which concerns on 2nd Embodiment of this invention. (A) is sectional drawing of the principal part of the oil return structure which concerns on 3rd Embodiment of this invention, (b) And (c) is sectional drawing which shows a manufacture process. (A) is a right side view of a part of the engine using the conventional engine return structure with the cover of the case lower and the pulsar cover removed, and (b) is a cross section taken along line BB in (a). FIG.

Explanation of symbols

8 Crank chamber 10 Crankcase end wall 17 Cam shaft 24 Chain 27 Chain tunnel 33, 33A, 33B Oil return passage 34 First return hole 35 Second return hole 38 Crank web A2 Crank shaft center E Engine OL Oil

Claims (3)

A chain tunnel that houses the chain for driving the camshaft is formed at the side end of the engine.
A chain sprocket over which the chain is bridged on one end of the crankshaft and a pulsar rotor for detecting the engine speed located outside the axial direction of the chain are mounted,
The pulsar rotor is housed in a pulsar chamber covered by a rotor cover;
The bottom surface of the pulsar chamber is located above the bottom surface of the crank chamber,
An oil return passage for returning the oil in the chain tunnel to the vicinity of the radial end of the crank web in the crank chamber is formed in the crankcase end wall that partitions the lower end portion of the chain tunnel and the crank chamber,
The oil return passage is provided in a vertical first return hole provided in the crankcase end wall, and is provided in the crankcase end wall to communicate the lower end portion of the first return hole and the crank chamber. A second return hole in the horizontal direction,
An oil return structure for an engine , wherein an inlet of the oil return passage is opened at a lower end portion of the pulsar chamber, and a lower end of an outlet of the oil return passage is located below the lower end of the crank chamber web . A chain tunnel that houses the chain for driving the camshaft is formed at the side end of the engine.
A chain sprocket over which the chain is bridged on one end of the crankshaft and a pulsar rotor for detecting the engine speed located outside the axial direction of the chain are mounted,
The pulsar rotor is housed in a pulsar chamber covered by a rotor cover;
The bottom surface of the pulsar chamber is located above the bottom surface of the crank chamber,
An oil return passage for returning the oil in the chain tunnel to the vicinity of the radial end of the crank web in the crank chamber is formed in the crankcase end wall that partitions the lower end portion of the chain tunnel and the crank chamber,
The oil return passage is formed of an inclined hole that is provided in the crankcase end wall and inclines the chain tunnel and the crank chamber with respect to the vertical direction.
An oil return structure for an engine , wherein an inlet of the oil return passage is opened at a lower end portion of the pulsar chamber, and a lower end of an outlet of the oil return passage is located below the lower end of the crank chamber web . A chain tunnel that houses the chain for driving the camshaft is formed at the side end of the engine.
A chain sprocket over which the chain is bridged on one end of the crankshaft and a pulsar rotor for detecting the engine speed located outside the axial direction of the chain are mounted,
The pulsar rotor is housed in a pulsar chamber covered by a rotor cover;
The bottom surface of the pulsar chamber is located above the bottom surface of the crank chamber,
An oil return passage for returning the oil in the chain tunnel to the vicinity of the radial end of the crank web in the crank chamber is formed in the crankcase end wall that partitions the lower end portion of the chain tunnel and the crank chamber,
The oil return passage is formed by a straight entry hole that enters the crankcase end wall from below and perpendicular to the crankshaft and communicates the chain tunnel with the crank chamber.
An oil return structure for an engine , wherein an inlet of the oil return passage is opened at a lower end portion of the pulsar chamber, and a lower end of an outlet of the oil return passage is located below the lower end of the crank chamber web .

Images