JP4895021B2 - Engine mount structure with variable valve timing mechanism - Google Patents

Description

  The present invention relates to a mount structure for an engine with a variable valve timing mechanism, in which an actuator cover portion that covers an actuator of a variable valve timing mechanism and a mount mounting portion for mounting a mount bracket project from a chain case.

In the DOHC engine, a variable valve timing mechanism (VVT) is provided on one or both of the intake and exhaust camshafts, and the opening and closing timing of at least one of the intake and exhaust valves is controlled according to the operating state of the engine. of the overlap amount is increased to reduce such improvements and NO _X of fuel consumption by the torque-up and internal EGR improvement by scavenging efficiency is conventionally performed.

  The variable valve timing mechanism includes an actuator that operates by hydraulic pressure to advance or retard the opening / closing timing of at least one of the intake and exhaust valves, and this actuator distributes oil supplied from an oil pump. Controlled by a hydraulic control valve to control.

  In an engine equipped with such a variable valve timing mechanism, the hydraulic control valve and the oil transfer part of the variable valve timing mechanism are unitized for the purpose of reducing the number of parts and facilitating assembly work, and this unit is placed in front of the camshaft. There has been a proposal to adhere to the front surface of the engine body (see Patent Document 1).

In addition, in an engine with a variable valve timing mechanism, a mount mounting portion for mounting the mount bracket protrudes from the outer surface of the chain case, and at least a hydraulic control valve is provided on the outer surface of the chain case above the mount mounting portion. Hydraulic control valve mounting structure that prevents the hydraulic control valve from coming into contact with the vehicle body and being damaged when the engine is attached to or removed from the vehicle body by mounting it so that part of it is covered by the mount mounting part Has been proposed (see Patent Document 2).
Japanese Patent Laid-Open No. 8-100611 JP 2000-199409 A

  By the way, when the mount mounting part is integrally formed on the chain case that covers the timing chain, if the mount mounting part is arranged at the center part of the chain case, the center part of the chain case is caused by repeated load from the engine that acts on the mount mounting part. There was a problem that noise was generated by vibration.

  Therefore, conventionally, a boss part joined to the engine body is formed at the center part of the chain case, and this boss part is fastened to the engine body with a bolt to suppress the vibration of the chain case, or a mount formed on the chain case. A method has been adopted in which the vibration of the chain case is suppressed by fastening the outer peripheral portion of the mounting portion together with the chain case to the flange portion of the engine body.

  However, in the former method, there is a problem that the fastening point increases and the productivity of the chain case is lowered, and in the latter method, the mount mounting portion is enlarged and the layout of peripheral parts is restricted. Had occurred.

  The present invention has been made in view of the above problems, and the object of the present invention is to increase the surface rigidity around the mount mounting portion without providing a fastening portion to the engine main body at the center portion of the chain case, thereby vibrating the chain case. Another object of the present invention is to provide a variable valve timing engine mount structure that can suppress noise generated thereby and improve the productivity of the chain case.

In order to achieve the above object, according to the first aspect of the present invention, a crankshaft is rotatably supported on a cylinder block, and a pair of intake and exhaust camshafts are rotatably supported on a cylinder head. A timing chain is wound between a crank sprocket attached to the cam sprocket attached to each of the intake and exhaust camshafts, and a chain case covering the timing chain is attached to the cylinder block and the cylinder head, An actuator of a variable valve timing mechanism is attached to at least one of the intake / exhaust camshafts, and an actuator cover portion that covers the actuator and a mount attachment portion for attaching a mount bracket project from the outer surface of the chain case. In the mounting structure of the variable valve timing mechanism with engine,
The mount mounting portion protruding from the chain case is connected to the lower portion of the actuator cover portion, and a step portion formed on the outer periphery of the actuator cover portion is extended in a planar shape toward the mount mounting portion, and a lower end portion thereof Is bonded to the mount mounting portion.

  According to a second aspect of the present invention, in the first aspect of the present invention, the hydraulic control valve for supplying oil to the actuator is attached to the chain case, and the control valve mounting cylinder portion for inserting the hydraulic control valve is attached to the stepped portion. The engine mounting structure with a variable valve timing mechanism according to claim 1, wherein the mounting structure is formed to extend along an inner surface of the actuator cover portion.

  A third aspect of the invention is characterized in that, in the first or second aspect of the invention, the stepped portion is formed so as to extend in a vertical direction in an in-vehicle state of the engine.

  The invention according to claim 4 is the invention according to claim 2 or 3, wherein the chain head can be joined to the cylinder head on the inner surface above the mount mounting portion of the chain case, and the hydraulic control valve and the cylinder are inside. An oil passage boss provided with an oil passage for communicating between the oil passages formed in the head is provided.

  According to the first aspect of the present invention, since the mount mounting portion protruding from the chain case is connected to the lower portion of the actuator cover portion, the actuator cover portion increases the surface rigidity around the mount mounting portion and the movement of the mount mounting portion. Is regulated. In addition, since the stepped portion formed on the outer periphery of the actuator cover portion extends flatly toward the mount mounting portion, and the lower end portion thereof is joined to the mount mounting portion, the surface rigidity around the actuator cover portion is enhanced by the stepped portion. Deformation of the entire chain case is suppressed.

  As a result, the surface rigidity around the mount mounting portion can be increased without providing a fastening portion to the engine body at the center of the chain case, and the vibration of the chain case and the noise generated thereby can be kept low. Further, since it is not necessary to provide a fastening portion for the engine body at the center of the chain case, the productivity of the chain case is enhanced.

  According to the second aspect of the present invention, the control valve mounting cylinder is formed in the chain case so as to extend from the step portion along the inner surface of the actuator cover. The vibration of the chain case and the noise generated thereby can be further reduced.

  According to the third aspect of the present invention, since the step portion is formed so as to extend in the vertical direction in the on-vehicle state of the engine, it is possible to effectively suppress deformation of the mount mounting portion in which the weight of the engine acts in the vertical direction. The vibration of the case and the noise generated thereby can be further suppressed.

  According to the invention described in claim 4, since the surface rigidity around the mount mounting portion is enhanced by the oil passage boss projecting from the inner surface of the chain case, the vibration of the chain case and the noise generated thereby are further suppressed. It is done.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  First, a basic configuration of an engine with a variable valve timing mechanism according to the present invention will be described with reference to FIGS.

  1 is a right side view of an engine with a variable valve timing according to the present invention, FIG. 2 is a front view of the engine, FIG. 3 is a plan view of the engine, and FIG. 4 is a perspective view with the head cover and chain case of the engine removed. An engine with a variable valve timing (hereinafter simply referred to as “engine”) 1 shown in FIG. 1 is a DOHC in-line four-cylinder engine for a vehicle. As shown in FIG. 1, the cylinder axis L is mounted on the vehicle in a state where the cylinder axis L is inclined forwardly with respect to the vertical line N by the angle θ shown in the figure.

  As shown in FIGS. 1 and 4, the crankshaft 2 is rotatably supported by a cylinder block 3, and four cylinders (not shown) are arranged in the vehicle width direction (the left-right direction in FIG. 2). ). Although not shown, pistons are slidably inserted into the cylinders of the cylinder block 3, and the pistons are connected to the crankshaft 2 via connecting rods along the cylinders of the pistons. The reciprocating linear motion is converted into rotational motion of the crankshaft 2 by the connecting rod.

  A cylinder head 4 is attached to the upper surface of the cylinder block 3, and an oil pan 5 is attached to the lower surface of the cylinder block 3. The cylinder head 4 has an intake port and an exhaust port (both for each cylinder). (Not shown) are formed. As shown in FIGS. 1 to 3, an intake manifold 6 connected to the intake port is connected to the intake side end surface (rear end surface) of the cylinder head 4. Here, the four intake manifolds 6 are gathered and connected to the surge tank 7, and although not shown, an air cleaner is connected to the upstream side of the surge tank 7 via a throttle body.

  On the other hand, as shown in FIGS. 1 to 3, an exhaust manifold 8 connected to the exhaust port is connected to the exhaust side end face (front end face) of the cylinder head 4, and the four exhaust manifolds 8 are assembled together. It is connected to the catalytic converter 9. An exhaust pipe 10 is connected to the catalytic converter 9, and the exhaust pipe 10 extends toward the rear of the vehicle body, and its rear end is open to the atmosphere.

  By the way, the intake port and the exhaust port formed for each cylinder in the cylinder head 4 are opened and closed at appropriate timings by an unillustrated intake valve and exhaust valve, respectively, so that a required gas exchange is performed in each cylinder. .

  Thus, as shown in FIG. 4, the intake valve and the exhaust valve are composed of an intake camshaft 11 rotatably supported on the cylinder head 4 and an intake cam 11a formed integrally with the exhaust camshaft 12, respectively. It is opened and closed by the exhaust cam 12a. Here, the intake camshaft 11 and the exhaust camshaft 12 are arranged in parallel in the left-right direction on the intake side (rear side of the vehicle body) and the exhaust side (front side of the vehicle body) of the cylinder head 4. An intake cam sprocket 13 and an exhaust cam sprocket 14 are respectively attached to the right end portion of the exhaust camshaft 12.

  As shown in FIG. 4, a crank sprocket 15 having a small diameter is attached to the right end portion of the crankshaft 2. An endless timing chain is connected to the crank sprocket 15, the intake cam sprocket 13, and the exhaust cam sprocket 14. 16 is wound. A head cover 17 is attached to the upper part of the cylinder head 4, and an intake camshaft 11, an exhaust camshaft 12, an intake cam sprocket 13, an exhaust cam sprocket 14 and the like are placed in a cam chamber formed in the head cover 17. Some are housed.

  Thus, the rotation of the crankshaft 2 is decelerated via the crank cam sprocket 15, the timing chain 16, the intake cam sprocket 13 and the exhaust cam sprocket 14 and transmitted to the intake camshaft 11 and the exhaust camshaft 12, respectively. The intake camshaft 11 and the exhaust camshaft 12 are rotationally driven at half the speed of the crankshaft 2 to open and close the intake valve and the exhaust valve at appropriate timings as described above. Gas exchange is performed.

  Here, the timing chain 16 is covered by a chain case 18 attached to each right end surface of the cylinder block 3 and the cylinder head 4, and the timing chain 16 is guided by a chain guide 19 in the chain case 18. On the other hand, it rotates in a state where a predetermined tension is applied by the tensioner 20, but since the crankshaft 2 rotates in the direction of the arrow in FIG. 4 (clockwise in FIG. 4), the timing chain 16 also rotates in the same direction. Therefore, in the timing chain 16, the exhaust side (chain guide 19 side) is a tight side, and the intake side (tensioner 20 side) is a loose side. For this reason, the loose side of the timing chain 16 moves in the chain case 18 from below to above.

  By the way, in the present embodiment, a variable valve timing mechanism for changing the opening / closing timing of the intake valve according to the engine speed or the like is provided, and this variable valve timing mechanism is provided at one end of the intake camshaft 11. The actuator 21 includes an actuator 21 that advances or retards the rotational phase of the intake camshaft 11 by hydraulic pressure, and a hydraulic control valve 22 that is attached to the chain case 18 and distributes and controls the oil supplied to the actuator 21. .

  Further, as shown in FIG. 4, a water pump housing 23 is integrally formed on the intake side of the cylinder block 3 so as to approach the center side (front side) of the cylinder block 3, and the right end of the cylinder block 3 and the cylinder head 4. A pair of flanges 3A, 3B and 4A, 4B are formed on the surface so as to avoid the water pump housing 23 and the intermediate height portion becomes concave toward the center. These flanges 3A, 3B and 4A, 4B form a joint surface to which the chain case 18 is attached, and a plurality of screw holes 24 are formed at appropriate intervals.

  Further, a head-side boss 25 projects from a portion of the right end surface of the cylinder head 4 that is close to the actuator 21 and is surrounded by the timing chain 16. An oil passage 26, an advance side oil passage 27, and a retard side oil passage 28 are formed.

  Incidentally, the water pump housing 23 formed in the cylinder block 3 accommodates a water pump (not shown) as an auxiliary machine, and a pulley 30 is provided on the input shaft 29 of the water pump as shown in FIG. It is bound. As shown in FIG. 1, a drive pulley 31 is attached to the right end portion of the crankshaft 2 that protrudes outward from the chain case 18, and a drive pulley (not shown) is connected to the drive pulley 31 and the pulley 30. The belt is wound, and the rotation of the crankshaft 2 is transmitted to the input shaft 29 of the water pump through the driving pulley 31 and the driving belt and pulley 30 (not shown), thereby driving the water pump.

  Next, the gist of the present invention will be described with reference to FIGS.

  5 is a front view of the chain case, FIG. 6 is a side view of the chain case (a view in the direction of arrow A in FIG. 5), FIG. 7 is a plan view of the chain case, and FIG. FIG. 9 is a perspective view of the main part of FIG. 8, and FIG. 10 is a sectional view taken along line BB of FIG.

  As shown in FIG. 5, the chain case 18 is attached to the outer periphery of the chain case 18 by a plurality of bolts 32 (see FIG. 1), and the flange 3A, 3B and 4A, 4B of the cylinder block 3 and the cylinder head 4 (FIG. 4). A pair of left and right flanges 18A and 18B are formed for fastening to a plurality of circular holes 33 through which bolts 32 (see FIG. 1) are inserted at appropriate intervals. Is formed. These flanges 18A and 18B have the same shape as the flanges 3A and 3B and 4A and 4B formed on the cylinder block 3 and the cylinder head 4 shown in FIG. A pair of recesses 18 a and 18 b that are recessed toward the center of 18 are formed. As shown in FIGS. 5 to 7, a truncated pyramid-shaped mount mounting portion 34 projects integrally on the outer surface of the connecting wall that connects the flanges 18 </ b> A and 18 </ b> B between the recesses 18 a and 18 b of the chain case 18. Bolt holes 33a, 33b, and 33c are respectively provided in the lower portion, inside, and rear portion of the mount attachment portion 34, and the mount attachment portion 34 is provided by bolts 32 that are inserted into the bolt holes 33a, 33b, and 33c. Is fastened to the cylinder block 3 and the cylinder head 4. As shown in FIGS. 1 to 3, the mount bracket 35 is attached to the upper surface of the mount attachment portion 34 by a plurality of bolts 36.

  Further, as shown in FIG. 5, an actuator cover portion 18 </ b> C that covers the actuator 21 (see FIG. 4) protrudes above the mount mounting portion 34 on the outer surface of the chain case 18. Is connected to the lower portion of the actuator cover portion 18C. A step 18c is formed in the actuator cover 18C of the chain case 18, and the step 18c is extended in a plane toward the mount mounting portion 34 in the vertical direction in the vehicle-mounted state of the engine 1. The lower end portion is joined to the mount mounting portion 34. The hydraulic control valve 22 is inserted into the chain case 18 from the stepped portion 18c and fixed.

  That is, as shown in FIGS. 9 and 10, a control valve mounting cylinder 37 for inserting the hydraulic control valve 22 from the stepped portion 18c is formed on the inner surface of the chain case 18 above the mount mounting portion 34. It is integrally formed so as to extend from the step portion 18c along the inner surface of the actuator cover portion 18C. An oil passage boss 38 projects from a portion of the inner surface of the chain case 18 that overlaps the control valve mounting cylinder 37.

  The oil passage boss 38 is provided with a supply side oil passage 39, an advance side oil passage 40 and a retard side oil passage 41, and when the chain case 18 is attached to the end faces of the cylinder block 3 and the cylinder head 4, The oil passage boss 38 is joined to the head side boss 25 (see FIG. 4) projecting from the cylinder head 4, and the supply side oil passage 39, the advance side oil passage 40 and the retard angle formed in the boss 38. The side oil passage 41 is connected to the supply side oil passage 26, the advance side oil passage 27, and the retard side oil passage 28 formed in the head boss 25.

  Thus, oil of a predetermined pressure from an oil pump (not shown) driven by the crankshaft 2 passes from an oil passage (not shown) formed in the cylinder head 4 to the head side boss 25 and the oil passage boss 38 of the chain case 18. When supplied to the hydraulic control valve 22 from the formed supply-side oil passages 26 and 39, the hydraulic control valve 22 distributes and controls this oil to drive the actuator 21, and the opening / closing timing of the intake valve is set to the engine speed, etc. Control appropriately according to.

  That is, the advance side in the actuator 21 through the advance side oil passages 40 and 27 formed in the oil passage boss 38 and the head side boss 25 and the advance side oil passage (not shown) formed in the cylinder head 4. When oil is supplied to the oil chamber, the rotational phase of the intake camshaft 11 is advanced, and the opening / closing timing of the intake valve is advanced.

  Similarly, the retard angle in the actuator 21 is passed through the retard angle side oil passages 41 and 28 formed in the oil passage boss 38 and the head side boss 25 and the retard angle side oil passage (not shown) formed in the cylinder head 4. When oil is supplied to the oil chamber on the side, the rotational phase of the intake camshaft 11 is retarded and the opening / closing timing of the intake valve is delayed.

  As described above, in the present embodiment, since the mount mounting portion 34 protruding from the chain case 18 is connected to the lower portion of the actuator cover portion 18C as described above, the surface rigidity around the mount mounting portion 34 is increased by the actuator cover portion 18C. As a result, the movement of the mount mounting portion 34 is restricted. Further, the step portion 18c formed on the outer periphery of the actuator cover portion 18C extends in a planar shape toward the mount attachment portion 34, and the lower end portion thereof is joined to the mount attachment portion 34. Therefore, the step portion 18c causes the periphery of the actuator cover portion 18C to be surrounded. The surface rigidity is increased and deformation of the entire chain case 18 is suppressed.

  As a result, the surface rigidity around the mount mounting portion 34 can be increased without providing a fastening portion to the engine body at the center of the chain case 18, and the vibration of the chain case 18 and the noise generated thereby can be kept low. Further, since it is not necessary to provide a fastening portion for the engine body at the center of the chain case 18, the productivity of the chain case 18 is improved.

  In the present embodiment, the control valve mounting cylinder 37 is formed on the chain case 18 so as to extend from the step 18c along the inner surface of the actuator cover 18C. The surface rigidity of 18C is increased, and the vibration of the chain case 18 and the noise generated thereby are further suppressed.

  Further, in the present embodiment, the step 18c is formed in the chain case 18 so as to extend in the vertical direction when the engine 1 is mounted on the engine 1, so that the mount mounting portion 34 in which the weight of the engine 1 acts in the vertical direction is effectively deformed. The vibration of the chain case 18 and the noise generated thereby can be further reduced.

  Further, since the oil passage boss 38 protruding from the inner surface of the chain case 18 increases the surface rigidity around the mount mounting portion 34, the vibration of the chain case 18 and the noise generated thereby can be further reduced. .

It is a right view of the engine with a variable valve timing which concerns on this invention. 1 is a front view of an engine with a variable valve timing according to the present invention. It is a top view of the engine with a variable valve timing concerning the present invention. It is a perspective view which removes and shows the head cover and chain case of an engine with a variable valve timing concerning the present invention. It is a front view of the chain case of the engine with a variable valve timing which concerns on this invention. It is a side view (figure of the arrow A direction of FIG. 5) of the chain case of the engine with a variable valve timing which concerns on this invention. It is a top view of the chain case of the engine with a variable valve timing which concerns on this invention. It is the internal view which looked at the chain case of the engine with a variable valve timing which concerns on this invention from the inner side. It is a principal part perspective view of FIG. FIG. 10 is a sectional view taken along line B-B in FIG. 9.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine with variable valve timing mechanism 2 Crankshaft 3 Cylinder block 3A, 3B Cylinder block flange 4 Cylinder head 4A, 4B Cylinder head flange 5 Oil pan 6 Intake manifold 7 Surge tank 8 Exhaust manifold 9 Catalytic converter 10 Exhaust pipe 11 Intake Camshaft 11a Intake cam 12 Exhaust camshaft 12a Exhaust cam 13 Intake cam sprocket 14 Exhaust cam sprocket 15 Crank sprocket 16 Timing chain 17 Head cover 18 Chain case 18A, 18B Chain case flange 18C Chain case actuator cover 18a, 18b Chain case Recessed part 18c Step part of actuator cover part 19 Chain guide 20 Tensioner 2 Actuator 22 Hydraulic control valve 23 Water pump housing 24 Screw hole 25 Head side boss 26 Supply side oil passage 27 Advance angle side oil passage 28 Delay angle side oil passage 29 Water pump input shaft 30 Pulley 31 Drive pulley 32 Bolt 33 Circular hole 34 Mount mounting part 35 Mount bracket 36 Bolt 37 Control valve mounting cylinder 38 Oil passage boss 39 Supply side oil passage 40 Advance side oil passage 41 Delay side oil passage L Cylinder axis N Vertical line

Claims (4)

A crankshaft is rotatably supported on the cylinder block, and a pair of intake / exhaust camshafts are rotatably supported on the cylinder head, and each of the crank sprocket attached to the crankshaft and the intake / exhaust camshafts are respectively supported. A timing chain is wound between the attached cam sprocket and a chain case covering the timing chain is attached to the cylinder block and the cylinder head, and at least one of the intake and exhaust camshafts is provided with a variable valve timing mechanism. A mounting structure for an engine with a variable valve timing mechanism, in which an actuator is mounted and a mount mounting portion for mounting an actuator cover portion and a mounting bracket for mounting the actuator is projected on the outer surface of the chain case. In,
The mount mounting portion protruding from the chain case is connected to the lower portion of the actuator cover portion, and a step portion formed on the outer periphery of the actuator cover portion is extended in a planar shape toward the mount mounting portion, and a lower end portion thereof A structure for mounting an engine with a variable valve timing mechanism, wherein:   A hydraulic control valve for supplying oil to the actuator is attached to the chain case, and a control valve mounting cylinder portion for inserting the hydraulic control valve is formed to extend from the step portion along the inner surface of the actuator cover portion. The mount structure for an engine with a variable valve timing mechanism according to claim 1.   The mount structure for an engine with a variable valve timing mechanism according to claim 1 or 2, wherein the stepped portion is formed so as to extend in a vertical direction in an in-vehicle state of the engine.   An oil passage that can be joined to the cylinder head on the inner surface above the mount mounting portion of the chain case and communicates between the oil pressure control valve and the oil passages formed in the cylinder head is provided. 4. The mount structure for an engine with a variable valve timing mechanism according to claim 2, wherein an oil passage boss is provided in a protruding manner.

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