JP2013113166A - Cover structure for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cover structure for an internal combustion engine that allows lubricating oil to surely flow while preventing interference between ribs and a timing chain.SOLUTION: A cover structure for an engine E includes a chain case 30 that covers a cam timing chain 24. The chain case 30 includes: bolt insertion holes 31a, 31b provided in side edges 31, 32 and fastened to an engine body 10; a first rib 35 that protrudes from a wall 33 to the engine body 10 side, is provided inside the cam timing chain 24, and extends along in a cylinder axial direction; and a second rib 36 that protrudes from the wall 33 to the engine body 10 side, is provided between the side edge 32 and the first rib 35, and is inclined so as to be located at the lower part in the cylinder axial direction as going toward the first rib 35. The first rib 35 is formed higher than the second rib 36 and its lower end is located at the upper part in the cylinder axial direction of a crank sprocket 21. The upper end of the second rib 36 is formed higher than the halfway part in the length direction.

Description

  The present invention relates to a cover structure for an internal combustion engine.

  Generally, a rib that reinforces the chain case is provided in a chain case that covers a timing chain that transmits rotation of an engine crankshaft to a camshaft.

  By the way, a large amount of lubricating oil for lubricating the timing chain is scattered in the chain case when the engine is driven. If this lubricating oil stays, problems such as deterioration of the lubricating performance occur. It is desirable to ensure that Therefore, conventionally, lubricating oil is flowed using a reinforcing rib.

  For example, in Patent Document 1, a pair of main ribs that extend obliquely downward from the inner surfaces of both side edges of the chain case toward the center and then extend downward toward the crankshaft are formed and arranged between the main ribs. An invention has been disclosed in which an oil guide passage is provided between main ribs by making the height of the provided ribs smaller than the height of the main ribs.

  The lubricating oil flowing along the inner surfaces of both side edges of the chain case is collected in the oil guide passage along the main rib, and then guided to the meshing portion between the timing chain and the crank sprocket.

Japanese Patent No. 311845

  However, in the invention described in Patent Document 1, since a pair of main ribs having relatively large dimensions are formed in the width direction and the length direction of the chain case, there is a possibility that interference between the main ribs and the timing chain occurs. . Therefore, although it is necessary to reduce the height of the main rib, there is a possibility that the main rib cannot sufficiently exhibit the function of guiding the lubricating oil, and the lubricating oil cannot be reliably flowed.

  The present invention has been developed from such a viewpoint, and an object of the present invention is to provide a cover structure for an internal combustion engine that can flow lubricating oil reliably while preventing interference between a rib and a timing chain.

  In order to solve the above problems, the present invention provides a drive wheel and a driven wheel provided in an internal combustion engine body, an endless timing chain spanned between the drive wheel and the driven wheel, and the internal combustion engine body. And a cover member for forming the timing train chamber and covering the timing chain, wherein the cover member is provided at a pair of side edges that are spaced apart from each other. A first portion extending from the inner surface of the internal combustion engine body to the internal combustion engine body, extending along the cylinder axial direction, and projecting from the inner surface of the wall portion connecting the fastening portion fastened to the pair of side edge portions A rib projecting from the inner surface of the wall portion toward the internal combustion engine main body, provided between both or one of the pair of side edge portions and the first rib, toward the first rib. A second rib that is inclined so as to be positioned below the cylinder axial direction, the first rib being formed higher than the second rib, and a cylinder axially lower end portion of the driving wheel. The second rib is positioned above the axial direction, and the end of the side edge portion is formed higher than the middle portion in the length direction.

According to the present invention, since the second rib is provided between the first rib extending along the cylinder axial direction and both or one of the pair of side edges, the side edge of the cover member is provided. The lubricating oil flowing along is surely guided to the second rib. Further, since the second rib is inclined so as to be positioned lower in the cylinder axial direction toward the first rib, and the first rib is formed higher than the second rib, the lubrication guided to the second rib. The oil is reliably guided to the first rib through the second rib by its own weight. Furthermore, since the first rib has a lower end in the cylinder axial direction positioned above the drive wheel in the cylinder axial direction, the lubricating oil guided to the first rib is transmitted to the drive wheel through the first rib by its own weight. Guided reliably.
Therefore, the first and second ribs can surely flow the lubricating oil flowing along the side edge of the cover member to the drive wheels.

According to the present invention, since the first rib is provided inside the timing chain, it is possible to prevent interference between the first rib and the timing chain. And since both interference can be prevented, the height of the 1st rib can be set up freely.
In addition, since the second rib is formed such that the end on the side edge side is higher than the middle part in the length direction, the timing chain is disposed so as to pass the middle part in the length direction of the second rib. The interference between the second rib and the timing chain can be prevented.

  Further, the present invention includes a sliding contact member that slides on the timing chain and applies a predetermined tension, and an abutting portion that contacts the sliding contact member, and the sliding contact member is attached to the timing chain. A drain oil passage communicating with the drain portion of the hydraulic control valve is provided in the vicinity of one of the pair of side edge portions, and the contact portion includes the drain portion. Preferably, the second rib is provided below the oil passage in the cylinder axial direction, and the second rib is provided above the drain oil passage in the cylinder axial direction.

  According to this configuration, the abutting portion of the urging member that abuts the sliding contact member is provided below the drain oil passage in the cylinder axial direction communicating with the drain portion of the control valve, and the second rib is the drain oil passage. Therefore, the lubricating oil that has flowed out of the drain oil passage into the cover member is easily guided to the contact portion without being guided to the second rib. Thereby, the space between the sliding contact member and the contact portion is lubricated, and as a result, the lubricating oil can be distributed and lubricated between the drive wheel and the contact portion.

  Moreover, it is preferable that the cover member further includes a third rib that protrudes from the one side edge portion toward the contact portion side and is provided below the drain oil passage in the cylinder axial direction. .

  According to such a configuration, the lubricant that has flowed out from the drain oil passage into the cover member by projecting from the side edge portion toward the contact portion side and having the third rib provided below the drain oil passage in the cylinder axial direction. The oil is more easily guided by the contact portion along the third rib. Thereby, it becomes easier to lubricate between the sliding contact member and the contact portion.

  ADVANTAGE OF THE INVENTION According to this invention, the cover structure of the internal combustion engine which can flow lubricating oil reliably can be provided, preventing interference of a rib and a timing chain.

It is a schematic block diagram of an engine provided with the cover structure of an internal combustion engine, (a) is a side view, (b) is a front view. It is a side view which shows the state which removed the chain case from the engine. (A) is a rear view of a chain case, (b) is the II sectional view taken on the line of (a). It is a perspective view which shows the state which looked at the chain case from the cylinder axis direction diagonally downward. It is a partially omitted front view of the chain case. FIG. 4 is a partially enlarged perspective view showing the periphery of a first oil passage boss in FIG. FIG. 4 is a partially enlarged perspective view showing the periphery of a variable valve boss portion and a second oil passage boss portion of FIG. FIG. 6 is a partially enlarged perspective view showing the periphery of the strainer mounting portion of FIG. 5. It is the II-II sectional view taken on the line of FIG. FIG. 3 is a partially omitted perspective view showing a state in which the periphery of the crank sprocket is enlarged and viewed from the engine body side. It is the side view which showed typically the flow of the lubricating oil seen from the chain case side. It is the side view which showed typically the flow of the lubricating oil seen from the engine main body side.

  Embodiments of the present invention will be described in detail with reference to the drawings. In the description, the same elements are denoted by the same reference numerals, and redundant description is omitted. In the present embodiment, a case where the present invention is applied to an automobile engine will be described as an example. Moreover, when explaining a direction, it demonstrates based on the front-back, up-down, right-and-left of the vehicle shown in FIG.

  In the present embodiment, the vertical direction coincides with the vertical direction, and the cylinder axial direction is inclined forward by a predetermined angle with respect to the vertical direction (vertical direction). The axial direction is a direction parallel to the rotation centers of the crankshaft and the camshaft. Furthermore, the orthogonal direction is a direction orthogonal to the cylinder axial direction when viewed from the axial direction. The upper side is referred to as the upper side and the lower side is referred to as the lower side with respect to the cylinder orthogonal plane that is a plane orthogonal to the cylinder axial direction.

FIG. 1 is a schematic configuration diagram of an engine E provided with a cover structure for an internal combustion engine, in which (a) is a side view and (b) is a front view. FIG. 2 is a side view showing a state where the chain case 30 is removed from the engine E. FIG.
As shown in FIGS. 1 (a) and 1 (b), the engine E is, for example, a DOHC type in-line engine placed horizontally on a vehicle body. The engine E mainly includes an engine body 10, a timing train mechanism 20, and a chain case 30.

<Engine body>
As shown in FIG. 2, the engine body 10 includes a cylinder block 11, a lower block 12, a cylinder head 13, a head cover 14, and an oil pan 15.

<Cylinder block>
Although not shown, the cylinder block 11 is a member mainly constituting a cylinder bore and a crankcase. Inside the cylinder block 11, a piston, a connecting rod, a crankshaft 16 and the like are accommodated.

<Lower block>
The lower block 12 is a member that forms a crankcase together with the cylinder block 11, and is disposed below the cylinder block 11. An end portion of the crankshaft 16 is rotatably held between the side wall 11a of the cylinder block 11 and the side wall 12a of the lower block 12.

<Cylinder head>
The cylinder head 13 is a member that forms a combustion chamber together with the cylinder block 11, and is disposed above the cylinder block 11. Although not shown, an intake port and an exhaust port communicating with the combustion chamber are formed inside the cylinder head 13, and an intake valve, an exhaust valve, a rocker arm, and the like for opening and closing the intake port and the exhaust port are disposed. Is done. Two camshafts 17 are disposed above the cylinder head 13. The camshaft 17 constitutes an intake side camshaft 18 and an exhaust side camshaft 19. The intake side camshaft 18 and the exhaust side camshaft 19 are arranged side by side so that their axial directions are parallel to each other.

  A plurality of bolt insertion holes 10a, 10a are spaced along the extending direction at both ends in the width direction of the side wall 11a of the cylinder block 11, the side wall 12a of the lower block 12, and the side wall 13a of the cylinder head 13. It is formed by emptying. In addition, an oil dropping portion 10 b that supplies oil into the chain case 30 opens on the side wall 13 a of the cylinder head 13.

<Head cover>
The head cover 14 is a lid-like member that closes the upper part of the cylinder head 13 and constitutes a valve operating chamber, and is disposed above the cylinder head 13. End portions of the intake side camshaft 18 and the exhaust side camshaft 19 are rotatably fixed to the side wall 14 a of the head cover 14.

<Oil pan>
The oil pan 15 is a member for receiving oil falling by lubricating each part in the engine E, and is disposed below the lower block 12. Inside the oil pan 15, an oil pump 15 a for pumping oil to each part in the engine E is disposed. One end side of the pump drive shaft 15 b of the oil pump 15 a protrudes from the side wall 15 c of the oil pan 15.

  The crankshaft 16 functions as a drive shaft, and the intake side camshaft 18, the exhaust side camshaft 19, and the pump drive shaft 15b each function as a driven shaft.

<Timing train mechanism>
The timing train mechanism 20 is a mechanism that transmits the rotational force of the crankshaft 16 to the pump drive shaft 15 b and the camshaft 17.
The timing train mechanism 20 includes a crank sprocket 21, cam sprockets 22A and 22B, an oil pump sprocket 23, a cam timing chain 24, an oil pump timing chain 25, a movable shoe 26A, and a first fixed shoe 26B. A second fixed shoe 26C, a first hydraulic tensioner device 27, a shoe 28, and a second hydraulic tensioner device 29.

<Crank sprocket>
The crank sprocket 21 that is a drive wheel is a gear member that is fixed to one end side of the crankshaft 16 protruding from the side surface of the engine body 10 and is configured to be rotatable integrally with the crankshaft 16. The crank sprocket 21 includes a first gear portion 21a having a large diameter and a second gear portion 21b having a small diameter. The first gear portion 21a is disposed closer to the engine body 10 than the second gear portion 21b. In the present embodiment, the crank sprocket 21 (crankshaft 16) rotates in the clockwise direction in FIG.

<Cam sprocket>
The cam sprockets 22 </ b> A and 22 </ b> B that are driven wheels are gear members that are fixed to one end sides of two camshafts 17 that protrude from the side surface of the engine body 10 and that can rotate integrally with the camshaft 17. . The cam sprocket 22 </ b> A is connected to the intake side camshaft 18, and the cam sprocket 22 </ b> B is connected to the exhaust side camshaft 19. As the cam sprockets 22A and 22B rotate, the intake side camshaft 18 and the exhaust side camshaft 19 rotate to open and close the intake and exhaust valves at a predetermined timing.

<Cam timing chain>
The cam timing chain 24 as a timing chain is an endless chain that transmits the rotational force of the crankshaft 16 to the camshaft 17, and is hung between the second gear portion 21b of the crank sprocket 21 and the cam sprockets 22A and 22B. Passed.

<Moving shoe>
The movable shoe 26 </ b> A serving as a sliding contact member is an elongate long member that is in sliding contact with the loose side (left side in FIG. 2) of the cam timing chain 24 and guides the cam timing chain 24. The upper end of the movable shoe 26A is fixed to the side wall 13a of the cylinder head 13 so as to be swingable. The lower end side of the movable shoe 26 </ b> A is urged toward the cam timing chain 24 by the first hydraulic tensioner device 27.

<First fixed shoe>
The first fixed shoe 26 </ b> B is a linear long member that slides into contact with the tension side portion of the cam timing chain 24 (the right side portion in FIG. 1) and guides the cam timing chain 24. The first fixed shoe 26 </ b> B is fixed by a plurality of bolts B and B across the side wall 11 a of the cylinder block 11 and the side wall 13 a of the cylinder head 13.

<Second fixed shoe>
The second fixed shoe 26C is a linear member that is disposed above the cam sprockets 22A and 22B, is in sliding contact with the cam timing chain 24, and guides the cam timing chain 24. The second fixed shoe 26C is fixed to the head cover 14.

<First hydraulic tensioner device>
The first hydraulic tensioner device 27 is a device that adjusts the tension of the cam timing chain 24 to be substantially constant by urging the movable shoe 26 </ b> A toward the cam timing chain 24. The first hydraulic tensioner device 27 includes a contact portion 27a that contacts the movable shoe 26A, a housing 27b that is fixed to the side wall 12a of the lower block 12, and a plunger 27c that protrudes from the housing 27b and presses the contact portion 27a. Have.

  The contact part 27a is a substantially triangular member disposed on the lower end side of the movable shoe 26A. The abutting portion 27 a has an inner lower end fixed to the side wall 11 a of the cylinder block 11 so as to be swingable. The outer lower end portion of the contact portion 27a is biased toward the movable shoe 26A by the plunger 27c.

  High pressure oil is supplied to the housing 27b from an oil supply oil passage (not shown) of the engine body 10. In this case, when the contact portion 27a is pressed toward the movable shoe 26A by the plunger 27c pushed out from the housing 27b (when it swings clockwise in FIG. 2), the movable shoe 26A is interposed via the contact portion 27a. Is pressed toward the cam timing chain 24, and the tension of the cam timing chain 24 is adjusted to be substantially constant.

<Sprocket for oil pump>
The oil pump sprocket 23 is a gear member fixed to the pump drive shaft 15 b protruding from the side wall 15 c of the oil pan 15. In this case, the pump drive shaft 15b rotates with the rotation of the oil pump sprocket 23, whereby the oil pump 15a is driven, and high-pressure oil passes through an oil supply passage (not shown) in various locations in the engine body 10. To be supplied.

<Timing chain for oil pump>
The oil pump timing chain 25 is an endless chain that transmits the rotational force of the crankshaft 16 to the pump drive shaft 15b, and is spanned between the first gear portion 21a of the crank sprocket 21 and the oil pump sprocket 23. It is.

<Shoe>
The shoe 28 is a member that contacts the loose side (the right side in FIG. 2) of the oil pump timing chain 25. The lower end of the shoe 28 is fixed to the second hydraulic tensioner device 29 so as to be swingable.

<Second hydraulic tensioner device>
The second hydraulic tensioner device 29 is a device that adjusts the tension of the oil pump timing chain 25 to be substantially constant by biasing the shoe 28 toward the oil pump timing chain 25. The second hydraulic tensioner device 29 includes a housing 29a fixed to the side wall 12a of the lower block 12, a plunger 29b that protrudes from the housing 29a and presses the shoe 28, and a hollow portion (not shown) formed in the housing 29a. A relief valve 29c to be accommodated.

  The housing 29a is a member that constitutes the body of the second hydraulic tensioner device 29, and includes an oil passage, a high hydraulic chamber, and the like therein. High pressure oil is supplied to the high hydraulic pressure chamber of the housing 29 a from an oil supply passage (not shown) of the engine body 10. In this case, the shoe 28 is pressed toward the oil pump timing chain 25 by the plunger 29b pushed out from the housing 29a, and the tension of the oil pump timing chain 25 is adjusted to be substantially constant.

  The relief valve 29c has a function of discharging oil from the relief hole 29c1 when the hydraulic pressure in the high hydraulic chamber of the housing 29a becomes equal to or higher than a predetermined value, and lubricating the timing train mechanism 20 using the discharged oil. The relief hole 29c1 of the relief valve 29c is formed so as to penetrate to the upper rear side of the housing 29a. The relief hole 29c1 can be provided at an arbitrary position of the housing 29a. In the present embodiment, the axis J1 of the relief hole 29c1 is arranged so that the meshing portions of the crank sprocket 21, the cam timing chain 24, and the oil pump timing chain 25 are arranged on the extension line of the axis J1 of the relief hole 29c1. The direction is adjusted.

<Chain case>
Returning to FIG. 1, the chain case 30 as a cover member is fixed to one side surface of the engine body 10 and covers the cam timing chain 24 from the outside. That is, the chain case 30 forms a timing train chamber S (see FIG. 1B) with the engine body 10 and covers the cam timing chain 24.

FIG. 3A is a rear view of the chain case 30, and FIG. 3B is a cross-sectional view taken along the line II of FIG. FIG. 4 is a perspective view showing a state in which the chain case 30 is viewed obliquely from below in the cylinder axis direction. 3A shows the crankshaft 16, the second gear portion 21b of the crank sprocket 21, and the cam timing chain 24 for convenience of explanation.
As shown in FIGS. 3A and 4, the chain case 30 is a member that has a U-shaped cross-sectional view, and a pair of side edge portions 31 and 32 that are separated from each other in the width direction (front-rear direction), And a wall 33 that connects the side edges 31 and 32.

<Side edge>
The side edge portions 31, 32 are portions that protrude from the both end portions in the width direction of the wall portion 33 toward the engine body 10 and are abutted and fixed to the engine body 10. A plurality of bolt insertion holes 31a and 32a are formed through the side edge portions 31 and 32 at intervals along the extending direction. The bolt insertion holes 31a and 32a as fastening portions are provided at positions corresponding to the bolt insertion holes 10a (see FIG. 2) of the engine body 10.

<Wall>
FIG. 5 is a partially omitted front view of the chain case 30.
As shown in FIGS. 3A and 5, the wall 33 includes a hydraulic control valve mounting portion 33a, a first oil passage boss portion 33b, a variable valve boss portion 33c, a strainer mounting portion 33d, It mainly includes a second oil passage boss 33e, three fastening bosses 33f1-33f3, and a plurality of ribs 34, 34.

<Hydraulic control valve mounting part>
As shown in FIG. 5, the hydraulic control valve mounting portion 33a is provided on the upper side of the outer surface 33g of the wall portion 33 and in the vicinity of the side edge portion 32, and is a portion to which a hydraulic control valve (not shown) is mounted. is there. The hydraulic control valve mounting portion 33a is formed to protrude from the outer surface 33g of the wall portion 33 by a predetermined length. Three circular holes 33a1-33a3 are formed through the hydraulic control valve mounting portion 33a. The hole 33a1 communicates with the oil supply path of the hydraulic control valve, the hole 33a2 communicates with the oil discharge path of the hydraulic control valve, and the hole 33a3 communicates with the drain part of the hydraulic control valve.

<First oil passage boss>
FIG. 6 is a partially enlarged perspective view showing the periphery of the first oil passage boss portion 33b of FIG.
As shown in FIG. 6, the first oil passage boss 33 b is formed to protrude from the inner surface 33 h (the surface facing the engine main body 10) 33 h of the wall 33 to the engine main body 10 by a predetermined length. The protruding end surface of the first oil passage boss portion 33 b abuts on one side surface of the engine body 10.
The first oil passage boss portion 33b includes an oil supply boss portion 33b1 and an oil discharge boss portion 33b2.

  The oil supply boss portion 33b1 is a portion configured by arranging concentric circular cylindrical portions having different diameters in an inner and outer double. A hole 33b3 that communicates with a hole 33a1 (see FIG. 5) of the hydraulic control valve mounting portion 33a and an oil passage (not shown) of the engine body 10 is formed in the inner cylindrical portion.

  The oil discharge boss portion 33b2 is formed in a substantially rectangular tube shape continuously from a concentric circular portion having different diameters arranged inside and outside and an outer peripheral surface of the outer cylindrical portion. And a portion. A hole 33b4 communicating with a hole 33a2 (see FIG. 5) of the hydraulic control valve mounting portion 33a and an oil passage (not shown) of the engine body 10 is formed in the inner cylindrical portion. A hole 33b5 that communicates with the hole 33a3 of the hydraulic control valve mounting portion 33a is formed in the substantially square cylindrical portion.

  In this case, the hole 33a1 and the hole 33b3 function as an oil supply oil passage for supplying oil from the engine body 10 to the hydraulic control valve, and the hole 33a2 and the hole 33b4 are oil from the hydraulic control valve to the engine body 10. It functions as an oil discharge oil passage that discharges oil. Further, the hole 33a3 and the hole 33b5 function as a drain oil passage D for supplying oil from the drain part of the hydraulic control valve into the chain case 30. In addition, the drain oil path D is arrange | positioned in the cylinder axial direction upper part of the inner surface 32b of the side edge part 32, as shown to Fig.3 (a). As a result, part of the oil supplied from the drain oil passage D flows reliably along the inner surface 32 b of the side edge portion 32. Further, the drain oil passage D is disposed above the contact portion of the contact portion 27a and the movable shoe 26A in the cylinder axial direction (see FIGS. 2 and 3A). Thereby, the oil supplied from the drain oil path D can be guided to the contact portion of the contact portion 27a and the movable shoe 26A.

<Voss for variable valve>
FIG. 7 is a partially enlarged perspective view showing the periphery of the variable valve boss portion 33c and the second oil passage boss portion 33e of FIG.
As shown in FIG. 7, the variable valve boss 33c is a portion having a substantially egg-shaped hole 33c1 into which a control valve (not shown) for controlling the variable valve timing mechanism is inserted. The variable valve boss portion 33 c is provided on the upper side of the wall portion 33 and in the center in the width direction. The variable valve boss portion 33 c is formed to protrude from the inner surface 33 h of the wall portion 33 to the engine main body 10 by a predetermined length, and its protruding end surface abuts against one side surface of the engine main body 10. The control valve is attached to the cylinder head 13 (see FIG. 2) via the hole 33c1 of the variable valve boss 33c.

<Second oil passage boss>
As shown in FIG. 7, the second oil passage boss portion 33e is a portion formed continuously on the outer periphery of the variable valve boss portion 33c. The second oil passage boss portion 33e is formed to protrude from the inner surface 33h of the wall portion 33 to the engine main body 10 by a predetermined length, and its protruding end surface is in contact with one side surface of the engine main body 10. The second oil passage boss 33e is formed with a substantially square cylindrical recess 33e1 and a cylindrical hole 33e2 having a predetermined volume. The recess 33e1 and the hole 33e2 communicate with an oil passage (not shown) of the engine body 10. The hole 33e2 communicates with the hole 33d2 of the strainer mounting portion 33d (see FIGS. 7 and 8).

<Strainer mounting part>
FIG. 8 is a partially enlarged perspective view showing the periphery of the strainer mounting portion 33d of FIG.
As shown in FIG. 8, the strainer mounting portion 33d is a portion provided below the variable valve boss portion 33c and to which a strainer (not shown) is mounted. The strainer mounting portion 33d is formed to protrude from the outer surface 33g of the wall portion 33 by a predetermined length. The strainer mounting portion 33d is formed with a substantially square cylindrical recess 33d1 and a cylindrical hole 33d2 having a predetermined volume. The recess 33d1 and the hole 33d2 communicate with the strainer.

9 is a cross-sectional view taken along line II-II in FIG.
As shown in FIGS. 5 and 9, the recess 33e1 of the second oil passage boss 33e is provided with a position shifted in the width direction with respect to the recess 33d1 of the strainer mounting portion 33d. A communication path 33i is formed between the recess 33e1 and the recess 33d1, as shown in FIG. One end of the communication path 33i opens to the side surface of the recess 33e1, while the other end opens to the bottom surface of the recess 33d1.

  In this case, the recess 33e1, the communication path 33i, and the recess 33d1 function as an oil supply oil passage that supplies oil from the engine body 10 to the strainer, and the hole 33d2 and the hole 33e2 supply oil from the strainer to the engine body 10. It functions as a return oil passage. Further, the recess 33e1 also functions as a chamber.

<Boss part for fastening>
The fastening boss portions 33f1-33f3 are cylindrical portions that are fixed to one side surface of the engine body 10 with bolts (not shown) as shown in FIG. The fastening boss portions 33f1 to 33f3 are formed to protrude from the inner surface 33h of the wall portion 33 to the engine main body 10 by a predetermined length, and the protruding end surfaces abut against one side surface of the engine main body 10. The fastening boss portions 33f1-33f3 are provided around the variable valve boss portion 33c and the second oil passage boss portion 33e with a space therebetween.

<Rib>
As shown in FIGS. 3A and 4, the rib 34 protrudes from the inner surface 33 h of the wall 33 to the engine body 10, and includes a plurality of ribs 34 along the cylinder axial direction, the orthogonal direction, the up-down direction, the front-rear direction, and the like. It is formed.
The rib 34 mainly includes a first rib 35, a second rib 36, a third rib 37, a fourth rib 38, and a fifth rib 39.

  The first rib 35 has an upper end portion (one end portion) continuous to the fastening boss portion 33f3, and a lower end portion (the other end portion) positioned near (directly above) the crank sprocket 21 and extending along the cylinder axial direction. It is a rib to do. As shown in FIG. 3A, the first rib 35 is provided inside the cam timing chain 24 (that is, a region surrounded by the cam timing chain 24). As shown in FIG. 4, the first rib 35 includes high rib portions 35a, 35a, a middle rib portion 35b having a lower height than the high rib portion 35a, and a low rib portion having a lower height than the middle rib portion 35b. 35c. The height of the high rib portion 35 a and the middle rib portion 35 b of the present embodiment is formed higher than the other ribs 34.

  The high rib portion 35 a is a portion that is formed at the middle portion and the lower end portion in the length direction of the first rib 35 and is in contact with one side surface of the engine body 10. The middle rib portion 35b is a portion formed between the fastening boss portion 33f3 and the upper high rib portion 35a. The low rib portion 35c is a portion formed between the high rib portions 35a and 35a and cut out by a predetermined length. The low rib portion 35c is provided in a portion close to the swing side (the contact portion 27a side) of the movable shoe 26A in the cylinder axial direction. By forming the low rib portion 35c, the cam timing chain 24 is stretched, and when pressed by the first hydraulic tensioner device 27 and the movable shoe 26A, the cam timing chain 24 and the first rib 35 are formed. Can be avoided (see FIGS. 2 and 3A).

  The first rib 35 is disposed on the tension side (first fixed shoe 26B side) of the cam timing chain 24, and a sufficient distance is provided between the first rib 35 and the loose side (movable shoe 26A) of the cam timing chain 24. If the height can be secured, the low rib portion 35c may be omitted, and the height of the portion corresponding to the low rib portion 35c may be increased. As a result, the oil can flow more reliably toward the meshing portions of the crank sprocket 21, the cam timing chain 24, and the oil pump timing chain 25.

  As shown in FIG. 3A, the second rib 36 is a linear rib provided between the inner surface 32 b of the side edge portion 32 and the middle rib portion 35 b of the first rib 35. The second rib 36 is inclined so as to be positioned downward in the cylinder axial direction toward the first rib 35. As shown in FIG. 3B, the second rib 36 is formed lower than the middle rib portion 35 b of the first rib 35. As shown in FIG. 4, the second rib 36 has high rib portions 36a, 36a and a low rib portion 36b having a height lower than that of the high rib portion 36a.

  The high rib portion 36a is a portion formed at the upper and lower end portions of the second rib 36, and is disposed above the drain oil passage D of the first oil passage boss portion 33b in the cylinder axial direction. By forming the high rib portion 36a, the lubricating oil flowing along the side edge portion 32 can be smoothly guided to the second rib 36 and reliably guided from the second rib 36 to the first rib 35. . The low rib portion 36b is a portion that is formed between the high rib portions 35a and 35a (that is, the middle portion in the length direction of the second rib 36) and is cut out by a predetermined length. By forming the low rib portion 36b, it is possible to avoid interference between the cam timing chain 24 and the second rib 36 (see FIG. 3A).

  As shown in FIG. 3A, the third rib 37 is disposed below the drain oil passage D of the first oil passage boss portion 33 b in the cylinder axial direction, and the first oil pressure from the inner surface 32 b of the side edge portion 32. It is a linear rib protruding toward the contact portion 27a side (see FIG. 2) of the tensioner device 27. The 3rd rib 37 inclines so that it may be located in a cylinder axial direction lower part, so that it goes to contact part 27a.

  As shown in FIG. 3A, the fourth rib 38 is arranged near the crank sprocket 21, and is a linear rib that protrudes from the inner surface 31 b of the side edge portion 31 toward the low rib portion 35 c of the first rib 35. It is. As shown in FIGS. 3A and 4, the fourth rib 38 is formed so as to be inclined so as to be positioned downward in the cylinder axial direction toward the first rib 35 and to gradually decrease its height. . By forming the fourth rib 38, the lubricating oil that has flowed along the side edge portion 31 can be guided to the first rib 35.

  As shown in FIGS. 3A and 4, the fifth rib 39 is a rib formed around the crankshaft insertion hole 30 </ b> A provided at the center lower portion in the width direction of the chain case 30. The fifth rib 39 is formed so as to surround the substantially outer periphery of the crankshaft insertion hole 30A, and is substantially orthogonal to (intersects) the annular rib 39a, and is formed radially with respect to the crankshaft insertion hole 30A. A plurality of radial ribs 39b, 39b.

FIG. 10 is a partially omitted perspective view showing a state in which the periphery of the crank sprocket 21 is enlarged and viewed from the engine body 10 side.
As shown in FIG. 10, in the annular rib 39a, a substantially rectangular cutout 39a1 is cut out at a portion on the extension line of the axis J1 of the relief hole 29c1. Thus, while reinforcing the periphery of the crankshaft insertion hole 30A, the lubricating oil injected from the relief hole 29c1 is surely injected into the meshing portions of the crank sprocket 21, the cam timing chain 24, and the oil pump timing chain 25. You can hang it.
Note that an opening 30B through which the first hydraulic tensioner device 27 (see FIG. 1A) can be seen is formed in front of the crankshaft insertion hole 30A.

The engine E having the cover structure for the internal combustion engine according to the present embodiment is basically configured as described above. Next, with reference to FIGS. explain. FIG. 11 is a side view schematically showing the flow of the lubricating oil as seen from the chain case 30 side, and FIG. 12 is a side view schematically showing the flow of the lubricating oil as seen from the engine body 10 side. is there.
In FIG. 11, for the sake of convenience of explanation, the first rib 35 to the fourth rib 38 are projected on the engine body 10. In FIG. 12, for convenience of explanation, the crankshaft 16, the second gear portion 21b of the crank sprocket 21, and the cam timing chain 24 are drawn.

  As shown in FIG. 11, when the crankshaft 16 is rotated by starting the engine E, the crank sprocket 21 attached to the crankshaft 16 is rotated, and the rotation is transmitted to the cam sprockets 22A and 22B by the cam timing chain 24. As the cam sprockets 22A and 22B rotate, the two camshafts 17 rotate. Thereby, an intake valve and an exhaust valve (not shown) are opened and closed at a predetermined timing.

  On the other hand, the rotation of the crank sprocket 21 is transmitted to the oil pump sprocket 23 by the oil pump timing chain 25, and the pump drive shaft 15b rotates with the rotation of the oil pump sprocket 23. As a result, the oil pump 15 a is driven, the oil in the oil pan 15 is pumped up, and the oil is supplied to each part of the engine E.

  A part of the oil is supplied into the chain case 30 via the meshing portion of the cam sprocket 22A and the cam timing chain 24, the oil dropping portion 10b, the drain oil passage D, and the like.

As shown in FIG. 12, the oil supplied into the chain case 30 flows downward along the inner surfaces 31 b and 32 b of the side edge portions 31 and 32 and the inner surface 33 h of the wall portion 33.
Among these, when the oil flowing along the side edge portion 32 and the wall portion 33 reaches the second rib 36, it flows along the second rib 36 toward the first rib 35.

At this time, since the second rib 36 has the high rib portion 36 a at the end portion on the side edge portion 32 side, the oil flowing along the side edge portion 32 can be reliably guided to the second rib 36.
Further, the second rib 36 is inclined so as to be positioned downward in the cylinder axial direction toward the first rib 35, and the first rib 35 is formed higher than the second rib 36. It is possible to reliably guide the oil flowing through the first rib 35 to the first rib 35.

  Subsequently, as shown in FIG. 11, when the oil flowing through the second rib 36 reaches the first rib 35, the crank sprocket 21, the cam timing chain 24, and the oil pump are transmitted through the first rib 35. It flows toward the meshing part of the timing chain 25 for use. Thereby, the said meshing part can be lubricated suitably.

  Also, as shown in FIG. 12, the oil supplied from the drain oil passage D flows downward along the inner surface 32 b of the side edge portion 32 and the inner surface 33 h of the wall portion 33.

At this time, since the drain oil passage D is disposed above a part of the inner surface 32b of the side edge portion 32 in the cylinder axial direction, a part of the oil supplied from the drain oil passage D is part of the inner surface of the side edge portion 32. It flows reliably along 32b.
Further, as shown in FIG. 11, the drain oil passage D is disposed above the contact portion of the contact portion 27 a and the movable shoe 26 </ b> A in the cylinder axial direction, and therefore a part of the oil supplied from the drain oil passage D. Flows along the inner surface 32b of the side edge portion 32 and the inner surface 33h of the wall portion 33 toward the contact portion of the contact portion 27a and the movable shoe 26A.

  11 and 12, when the oil flowing along the inner surface 32 b of the side edge portion 32 and the inner surface 33 h of the wall portion 33 reaches the third rib 37, the oil flows along the third rib 37 and reaches the third rib 37. 1 It flows toward the contact portion of the contact portion 27a of the hydraulic tensioner device 27 and the movable shoe 26A.

  At this time, the 3rd rib 37 protrudes toward the contact part 27a side of the 1st hydraulic tensioner device 27 from the inner surface 32b of the side edge part 32, and is located in a cylinder axial direction lower part, so that it goes to the contact part 27a. Therefore, the oil that has flowed along the side edge portion 32 can be reliably guided to the contact portion. Thereby, a contact location can be lubricated suitably.

  Further, as shown in FIG. 12, when the oil flowing along the inner surface 31 b of the side edge portion 31 and the inner surface 33 h of the wall portion 33 reaches the fourth rib 38, a part of the oil moves the fourth rib 38. It flows along the first rib 35.

  At this time, the fourth rib 38 protrudes from the inner surface 31b of the side edge portion 31 toward the first rib 35, and is inclined so as to be positioned downward in the cylinder axial direction toward the first rib 35. The oil that has flowed along the inner surface 31 b of the edge portion 31 can be suitably guided to the first rib 35.

  Next, as shown in FIG. 11, when the oil flowing through the fourth rib 38 reaches the first rib 35, the crank sprocket 21, the cam timing chain 24, and the oil pump are transmitted through the first rib 35. It flows toward the meshing part of the timing chain 25 for use. Thereby, the said meshing part can be lubricated still more suitably.

According to the present embodiment described above, the oil that has flowed along the inner surface 32b of the side edge portion 32 and the inner surface 33h of the wall portion 33 by the first rib 35 and the second rib 36 is supplied to the crank sprocket 21 and the cam. The timing chain 24 and the oil pump timing chain 25 can be reliably guided to the meshing portion.
Further, the oil that has flowed along the inner surface 31b of the side edge portion 31 and the inner surface 33h of the wall portion 33 is engaged with the crank sprocket 21, the cam timing chain 24, and the oil pump timing chain 25 by the fourth rib 38. Can be led to the department.
Further, the contact portion of the contact portion 27a and the movable shoe 26A is disposed below the drain oil passage D, while the second rib 36 is disposed above the drain oil passage D. The oil supplied from D and flowing along the inner surface 32b of the side edge portion 32 and the inner surface 33h of the wall portion 33 is guided to the contact portion of the contact portion 27a and the movable shoe 26A of the first hydraulic tensioner device 27. be able to. In particular, in the present embodiment, since the third rib 37 is disposed below the drain oil passage D, the third rib 37 can be further guided by the contact portion of the contact portion 27a and the movable shoe 26A.
Therefore, the oil in the chain case 30 does not stay and can be suitably lubricated by distributing the oil to the meshing portion and the contact portion.

According to the present embodiment, the highest first rib 35 among the ribs 34 is provided inside the cam timing chain 24, so that interference between the first rib 35 and the cam timing chain 24 can be prevented. And since interference of both can be prevented, the height of the 1st rib 35 can be set freely.
Further, since the relatively high second rib 36 of the ribs 34 has a low rib portion 36b in the middle in the length direction, the cam timing chain 24 is disposed so as to pass through the low rib portion 36b, thereby The interference between the two ribs 36 and the cam timing chain 24 can be prevented.

  As mentioned above, although embodiment of this invention was described in detail with reference to drawings, this invention is not limited to this, In the range which does not deviate from the main point of invention, it can change suitably.

  In the present embodiment, the present invention is applied to the engine E for automobiles, but may be applied to engines other than automobiles such as ships and general-purpose machines.

  In the present embodiment, the present invention is applied to the serial type engine E. However, the present invention may be applied to other types of engines (for example, a V-type engine).

  In the present embodiment, the cylinder axis direction is inclined at a predetermined angle forward with respect to the vertical direction (vertical direction), but the cylinder axis direction may be inclined at a predetermined angle rearward with respect to the vertical direction. It is good also as a structure corresponding to an up-down direction (vertical direction).

  In the present embodiment, the first rib 35 has three high rib portions 35a, medium rib portions 35b, and low rib portions 35c having different heights. However, the height of the first rib 35 is set as appropriate. For example, it is good also as a structure which has two rib parts from which height differs.

  In the present embodiment, the second rib 36 has two high rib portions 36a and low rib portions 36b having different heights. However, the height of the second rib 36 may be set as appropriate. It is good also as a structure which has three rib parts from which thickness differs.

  In the present embodiment, the second rib 36 is provided between the side edge portion 32 and the first rib 35, but the second rib 36 is provided between the side edge portion 31 and the first rib 35. Alternatively, the second rib 36 may be provided between the side edge portions 31 and 32 and the first rib 35.

In the present embodiment, the first hydraulic tensioner device 27 has the contact portion 27a and the contact portion 27a contacts the movable shoe 26A. However, the contact portion 27a is omitted and the plunger 27c is moved to the movable shoe. It is good also as a structure contact | abutted to 26A.
In this case, the positions of the movable shoe 26A, the plunger 27c, the drain oil passage D, and the fourth rib 38 are such that the oil supplied from the drain oil passage D is guided to the contact portion between the plunger 27c and the movable shoe 26A. Adjust as appropriate.

E engine (internal combustion engine)
10 Engine body (Internal combustion engine body)
21 Crank sprocket (drive wheel)
22A, 22B Cam sprocket (driven wheel)
24 cam timing chain (timing chain)
26A Movable shoe (sliding contact member)
27 First hydraulic tensioner device (biasing member)
27a Contact part 30 Chain case (cover member)
31, 32 Side edge portion 31a, 32a Bolt insertion hole (fastening portion)
33 Wall portion 33h Inner surface 34 Rib 35 First rib 36 Second rib 37 Third rib 38 Fourth rib D Drain oil passage S Timing train chamber

Claims (3)

A timing train chamber is formed between a drive wheel and a driven wheel provided in the internal combustion engine body, an endless timing chain spanned between the drive wheel and the driven wheel, and the internal combustion engine body to form the timing A cover structure for an internal combustion engine comprising a cover member for covering the chain,
The cover member is
Fastening portions that are provided at a pair of side edge portions that are separated from each other and fastened to the internal combustion engine body;
A first rib projecting from the inner surface of the wall portion connecting the pair of side edges toward the internal combustion engine body, provided inside the timing chain, and extending along a cylinder axial direction;
Projecting from the inner surface of the wall portion toward the internal combustion engine main body, provided between both or one of the pair of side edge portions and the first rib, and downward in the cylinder axial direction toward the first rib A second rib inclined so as to be located at
The first rib is formed higher than the second rib, and the lower end in the cylinder axial direction is positioned above the drive wheel in the cylinder axial direction,
The cover structure for an internal combustion engine, wherein the second rib is formed such that an end portion on the side edge portion side is higher than a middle portion in the length direction. A sliding contact member that slides on the timing chain and applies a predetermined tension;
An abutting portion that abuts against the sliding contact member, and further includes a biasing member that biases the sliding contact member toward the timing chain,
In the vicinity of either one of the pair of side edge portions, a drain oil passage communicating with the drain portion of the hydraulic control valve is provided,
The contact portion is provided below the drain oil passage in the cylinder axial direction,
The internal combustion engine cover structure according to claim 1, wherein the second rib is provided above the drain oil passage in the cylinder axial direction.   The said cover member further protrudes toward the said contact part side from said one side edge part, and further has the 3rd rib provided in the cylinder axial direction downward direction of the said drain oil path. The internal combustion engine cover structure described.

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