Control valve mounting structure for variable valve timing mechanism

Abstract

To provide a control valve mounting structure for a variable valve timing mechanism that can suppress damage to the electromagnetically controlled valve. [Solution] In the control valve mounting structure of the variable valve timing mechanism according to the present invention, the boss portion 22 attached to the valve housing portion 21 protrudes upward, i.e., toward the top dead center side of the cylinder axis Y, compared to the solenoid portion 62 exposed from the valve housing portion 21. As a result, obstacles approaching the internal combustion engine EG from the cam carrier 2 side (above) collide with the boss portion 22, which is located on the cam carrier 2 side (above) the solenoid portion 62, thereby suppressing damage to the solenoid portion 62.

Description

[Technical Field]

[0001] The present invention relates to a control valve mounting structure for a variable valve mechanism. [Background Art]

[0002] As a conventional control valve mounting structure for a variable valve mechanism, for example, one described in the following Patent Document 1 is known.

[0003] In a conventional control valve mounting structure for a variable valve mechanism, an electromagnetic control valve for controlling the supply and discharge of hydraulic oil to and from a retard side working chamber and an advance side working chamber, which are working chambers of the variable valve mechanism, is arranged on an upper surface of a front end portion of a cylinder head cover. In the electromagnetic control valve, a spool valve is housed in a valve housing portion provided on the upper surface of the front end portion of the cylinder head cover, and a solenoid portion connected to a base end portion of the spool valve is arranged so as to be exposed from an opening end of the valve housing portion. [Prior Art Literature] [Patent Literature]

[0004] [Patent Document 1] Japanese Unexamined Patent Publication No. 11-280430 [Summary of the Invention] [Problem to be Solved by the Invention]

[0005] However, in the above-described conventional control valve mounting structure for a variable valve mechanism, the solenoid portion exposed from the opening end of the valve housing portion is configured to protrude from the upper surface of the front end portion of the cylinder head cover. Therefore, for example, when carrying in an engine, there is a risk that the solenoid portion of the electromagnetic control valve may be damaged by an obstacle approaching from the cylinder head cover side (above), so there still remains room for improvement.

[0006] Therefore, the present invention was devised in view of the technical problems related to the control valve mounting structure of the variable valve timing mechanism, and aims to provide a control valve mounting structure for a variable valve timing mechanism that can suppress damage to the electromagnetic control valve. [Means for solving the problem]

[0007] In one aspect, the present invention provides a control valve mounting structure for a variable valve timing mechanism, wherein an electromagnetic control valve for controlling the supply and discharge of hydraulic fluid to the variable valve timing mechanism is mounted on a cylinder head cover mounted on the cylinder head of an engine equipped with a variable valve timing mechanism, the electromagnetic control valve comprises a spool valve housed in a cylindrical valve housing on the upper part of the cylinder head cover, which controls the supply and discharge of hydraulic fluid to the variable valve timing mechanism by switching an oil passage, and a solenoid unit attached to the opening of the valve housing for driving the spool valve, the valve housing extends laterally intersecting the cylinder axis, and has a boss portion on its side to which the solenoid unit is fixed, the boss portion is provided to protrude toward the top dead center in the direction of the cylinder axis, and protrudes toward the top dead center further than the solenoid unit. [Effects of the Invention]

[0008] According to the present invention, the boss portion attached to the valve housing protrudes upward, towards the top dead center of the cylinder axis, compared to the solenoid portion exposed from the valve housing. As a result, obstacles approaching the engine from the cylinder head cover side (above) collide with the boss portion located on the cylinder head cover side (above) than the solenoid portion, thereby suppressing damage to the solenoid portion. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic diagram showing the external appearance of the internal combustion engine according to the present invention. [Figure 2] Figure 1 is a front view of an internal combustion engine. [Figure 3] Figure 1 is a plan view of an internal combustion engine. [Figure 4]Figure 2 is an axial cross-sectional view of the electromagnetically controlled valve shown. [Figure 5] Figure 4 shows the operation diagram of the electromagnetic control valve, where (a) shows the state when the power is OFF and (b) shows the state when the power is ON. [Figure 6] This is a cross-sectional view along line AA in Figure 3. [Figure 7] Figure 3 is a cross-sectional view along line BB. [Modes for carrying out the invention]

[0010] Hereinafter, embodiments of the control valve mounting structure for the variable valve timing mechanism according to the present invention will be described in detail with reference to the drawings. In this embodiment, as with the conventional, an example is given in which the cylinder head structure of a top-injection type internal combustion engine is applied to the cylinder head cover of an automobile engine (spark-ignition type internal combustion engine). In the description of each figure, the direction parallel to the straight line connecting the centers of each cylinder of the cylinder head 1 is defined as the "cylinder row direction," the direction parallel to the central axis of each cylinder (cylinder axis Y) is defined as the "height direction," and the directions perpendicular to the cylinder row direction and the height direction are defined as the "width direction." Furthermore, the top dead center side is defined as "up," and the bottom dead center side is defined as "down."

[0011] Figure 1 shows a schematic diagram of the internal combustion engine (EG) according to this embodiment. Figure 2 shows a front view of the internal combustion engine (EG) shown in Figure 1, and Figure 3 shows a top view of the internal combustion engine (EG) shown in Figure 1.

[0012] For example, as shown in Figure 1, in the internal combustion engine EG according to this embodiment, a camshaft (e.g., exhaust camshaft) 4 is rotatably supported on the cylinder head 1 via the camcarrier 2, which is supported by a cam carrier 2, corresponding to the cylinder head cover according to the present invention and mounted on the upper part of the cylinder head 1, and a cam bracket 3 mounted on the lower part of the camcarrier 2. That is, the camcarrier 2 is fixed to the cylinder head 1 with the cylinder head mounting surface 20 facing the cylinder head 1 below the camcarrier 2 mounted on the cylinder head 1. Note that in Figure 1, for the sake of drawing convenience, only the exhaust camshaft is shown as the camshaft 4, but an intake camshaft (not shown) arranged in parallel with the exhaust camshaft is also rotatably supported by the camcarrier 2 and the cam bracket 3 in the same way as the exhaust camshaft.

[0013] Furthermore, a valve timing control device 5, which is a variable valve timing mechanism according to the present invention that changes the rotational phase of the camshaft 4 with respect to the crankshaft (not shown), is provided at the front end of the camshaft 4 extending in the longitudinal direction of the internal combustion engine EG. This device is housed inside a front cover 9, which is mounted on the front end of the internal combustion engine EG, together with a timing chain (not shown), which will be described later. The front cover 9 is fixed to the front end of the cylinder head 1 and the cam carrier 2 via a plurality of bolts B1 that are screwed into female threaded holes provided on the front end surface of the cylinder head 1 and into female threaded holes formed in a flange portion 23 that protrudes from the upper front end surface of the cam carrier 2 in a direction away from the cylinder head mounting surface 20 of the cam carrier 2.

[0014] The valve timing control device 5 includes a vane rotor 51 fixed to the front end of the camshaft 4 so as to be rotatable as an integral part of the valve timing control device, and a cylindrical housing 52 provided so as to be rotatable relative to the vane rotor 51 by a predetermined angle and rotating integrally with the cam sprocket 50. A timing chain (not shown) is wrapped around the cam sprocket 50, which is linked to a crank sprocket (not shown) provided on the crankshaft, so that the crankshaft (not shown) and the cam sprocket 50 can rotate synchronously.

[0015] The vane rotor 51 integrally comprises a cylindrical boss portion 511 fixed to the front end of the camshaft 4, and a plurality of vanes 512 (for example, four in this embodiment) arranged at predetermined intervals in the circumferential direction on the outer circumference of the boss portion 511 and projecting radially from the boss portion 511. On the other hand, the housing 52 integrally comprises a cylindrical housing body 521 and a plurality of shoes 522 (for example, four in this embodiment) projecting radially inward from the inner circumferential surface of the housing body 521. A retard-side working chamber P1 is formed between each vane 512 and one adjacent shoe 522, and an advance-side working chamber P2 is formed between each vane 512 and the other adjacent shoe 522.

[0016] Furthermore, on the upper front end surface of the cam carrier 2, as shown in Figures 2 and 3, for example, an electromagnetic control valve 6 is positioned horizontally so as to extend in the width direction of the internal combustion engine EG. This valve controls the supply and discharge of hydraulic fluid to the retard-side working chamber P1 and the advance-side working chamber P2 of the valve timing control device 5. The electromagnetic control valve 6 houses a spool valve 61, which will be described later, in a so-called sealed valve housing portion 21 that extends in the width direction on the upper front end surface of the cam carrier 2.

[0017] Furthermore, the electromagnetic control valve 6 is cantilevered to a boss portion 22 attached to the periphery of the opening 211 of the valve housing 21 by bolts B2, via an L-shaped bracket 620 attached (joined) to the outer circumferential surface of the solenoid portion 62, which will be described later and is exposed to the outside through the opening 211 of the valve housing 21. In this case, as in this embodiment, because the bottom portion 212 of the valve housing 21 is inclined downward, the solenoid portion 62 exposed through the opening 211 of the valve housing 21 is inclined diagonally upward, and the tip of the solenoid portion 62 (connector 623, described later), which is furthest from the opening 211 of the valve housing 21, is located on the top dead center side (corresponding to the upper side in Figure 1) of the opening 211 of the valve housing 21.

[0018] The boss portion 22 is provided so as to protrude toward the top dead center side (among top and bottom dead centers) in the cylinder axis Y direction, that is, toward the upper side of the internal combustion engine EG (corresponding to the upper side in FIG. 1), in a direction away from the cylinder head mounting surface 20 of the cam carrier 2. The electromagnetic control valve 6 is fixed via a single bolt B2 screwed into a female screw hole (not shown) provided near the distal end portion 220 of the boss portion 22, that is, the end portion on the side farthest from the cylinder head mounting surface 20 of the cam carrier 2 (the distal end portion 220 described later).

[0019] Here, in the cylinder axis Y direction, the boss portion 22 is configured such that at least the distal end portion 220 that is farthest from the cylinder head mounting surface 20 of the cam carrier 2 is located closer to the top dead center side than the distal end (connector 623 described later) of the solenoid portion 62 of the electromagnetic control valve 6, that is, in the direction away from the cylinder head mounting surface 20 of the cam carrier 2. Therefore, the boss portion 22 protrudes relatively larger relative to the height position of the solenoid portion 62 of the electromagnetic control valve 6.

[0020] Note that, as exemplified in the present embodiment (see FIGS. 1 and 2), the boss portion 22 is preferably provided so as to protrude in a direction generally perpendicular to the cylinder head mounting surface 20 of the cam carrier 2. However, it is only required that the boss portion 22 protrudes toward the top dead center side in the cylinder axis Y direction toward the side away from the cylinder head mounting surface 20 of the cam carrier 2 as shown in FIG. 1, and may be arranged to be tilted forward or rearward of the internal combustion engine EG.

[0021] Furthermore, the boss portion 22 is provided so as to extend along the longitudinal direction which is the depth direction of the valve accommodating portion 21 (the axial direction of the spool valve 61 described later). In other words, the boss portion 22 is provided so as to extend long in the width direction of the cam carrier 2.

[0022] Furthermore, regarding the arrangement of the solenoid portion 62 of the electromagnetic control valve 6, as shown in Figures 1 and 2, it is desirable that the valve housing portion 21 be located near the front cover 9, specifically near the flange portion 23 that secures the front cover 9. In this embodiment, for example, as shown in Figures 2 and 3, the valve housing portion 21 is located approximately adjacent to the rear end of the flange portion 23 when viewed from the front end of the internal combustion engine EG.

[0023] Furthermore, in this configuration, the flange portion 23 adjacent to the valve housing portion 21 is configured such that, when viewed from the front end of the internal combustion engine EG (see Figure 2), at least a portion of it overlaps with the solenoid portion 62 of the electromagnetic control valve 6. With this configuration, the flange portion 23, positioned in front of the solenoid portion 62, will collide first with any obstacle approaching from the front of the internal combustion engine EG, thereby suppressing damage to the solenoid portion 62.

[0024] Furthermore, in this case, it is desirable that the tip portion 230 of the flange portion 23 protrudes toward the side away from the cylinder head mounting surface 20 of the cam carrier 2 in the direction of the cylinder axis Y, as shown in Figure 2, for example. In other words, it is desirable that the tip portion of the solenoid portion 62 of the electromagnetic control valve 6 (connector 623, described later) is located in the region S on the cam carrier 2 side of the imaginary line V connecting the tip portion 220 of the boss portion 22 and the tip portion 230 of the flange portion 23.

[0025] Figure 4 shows a cross-sectional view of the electromagnetic control valve 6 cut along the central axis Z direction of the electromagnetic control valve 6. Figure 5 is an operation diagram of the electromagnetic control valve 6 shown in Figure 4, where (a) shows the state in which the solenoid section 62 is turned OFF, and (b) shows the state in which the solenoid section 62 is turned ON.

[0026] For example, as shown in Figure 4, the electromagnetic control valve 6 comprises a spool valve 61 housed in a valve housing 21 and a solenoid unit 62 that acts as a drive unit for driving the spool valve 61. An annular seal groove 654, which is continuous in the circumferential direction, is formed on the outer circumferential surface of the base end of the spool valve 61, and a sealing member 64, such as an O-ring, is attached to the seal groove 654. That is, the sealing member 64 provides a liquid-tight seal between the outer circumferential surface of the base end of the spool valve 61 and the inner circumferential surface of the opening 211 of the valve housing 21, thereby preventing foreign matter from entering the valve housing 21 from the outside.

[0027] The spool valve 61 comprises a generally bottomed cylindrical valve body 611, the base end connected to the solenoid portion 62 being open by an opening 611a and the tip opposite to the solenoid portion 62 being closed by an end wall 611b; a spool 612 provided on the inner circumference of the valve body 611 so as to be slidable along the central axis Z direction; and a biasing member 63 interposed between a stepped portion 611c, which is formed in a stepped manner with a reduced diameter on the opening 611a side of the valve body 611, and a third land portion 663 of the spool 612 (described later), which biases the spool 612 toward the solenoid portion 62.

[0028] The valve body 611 has an inlet 650 provided in the axial middle of its outer surface, through which hydraulic fluid is introduced from a longitudinal supply passage 72 (described later); a first supply / discharge hole 651 provided on the outer surface between the inlet 650 and the opening 611a, which supplies and discharges hydraulic fluid to and from the retard-side working chamber P1 via a first longitudinal supply / discharge passage 731 (described later); a second supply / discharge hole 652 provided on the outer surface between the inlet 650 and the end wall 611b, which supplies and discharges hydraulic fluid to and from the advance-side working chamber P2 via a second longitudinal supply / discharge passage 732 (described later); and a drain hole 653 provided on the end wall 611b, which drains the hydraulic fluid discharged from the first supply / discharge hole 651 or the second supply / discharge hole 652 to an oil pan (not shown).

[0029] The spool 612 includes a shaft portion 660 having a constant outer diameter, a first land portion 661 formed by expanding the diameter at one end of the shaft portion 660 (the side closer to the opening 611a) to open and close the first supply and discharge hole 651, a second land portion 662 formed by expanding the diameter at the other end of the shaft portion 660 (the side closer to the end wall 611b) to open and close the second supply and discharge hole 652, a third land portion 663 formed by expanding the diameter at the one end of the shaft portion 660 further than the first land portion 661, on which the biasing member 63 is seated, and an internal passage 664 extending axially (in the direction of the central axis Z) inside the shaft portion 660. In other words, the spool 612 has a first land portion 661 and a second land portion 662 that slide against the inner circumferential surface of the valve body 611, thereby forming a relay chamber 670 between the first land portion 661 and the second land portion 662, a first chamber 671 between the first land portion 661 and the opening 611a, and a second chamber 672 between the second land portion 662 and the end wall 611b.

[0030] Furthermore, the shaft portion 660 has an inlet portion 665 that penetrates radially at an axial position closer to the opening 611a than the first land portion 661 and connects the internal passage 664 and the first chamber 671, and an outlet portion 666 that penetrates axially at an axial position closer to the end wall 611b than the second land portion 662 and connects the internal passage 664 and the second chamber 672.

[0031] The solenoid section 62 comprises a casing 621 formed in a cylindrical shape from a metal material, a coil (not shown) housed on the inner circumference side of the casing 621, an armature (not shown) movably arranged on the inner circumference side of the coil, a rod 622 connected to the tip of the armature and in contact with the base end (axial end on the side facing the solenoid section 62) of the spool 612 via the opening 611a of the spool valve 61, and a connector 623 provided on the opposite side from the spool valve 61 and supplying control current to the coil.

[0032] With the above configuration, when the solenoid section 62 is in the OFF state, the electromagnetic control valve 6, for example as shown in Figure 5(a), has its spool 612 biased toward the opening 611a by the biasing force of the biasing member 63. As a result, the inlet hole 650 communicates with the first supply / discharge hole 651 via the relay chamber 670, and the hydraulic fluid flowing from the main oil gallery MG into the inlet hole 650 is supplied to the retard-side working chamber P1 via the relay chamber 670 and the first supply / discharge hole 651. On the other hand, the second supply / discharge hole 652 communicates with the drain hole 653 via the second chamber 672, and the hydraulic fluid flowing from the advance-side working chamber P2 into the second supply / discharge hole 652 is discharged to the oil pan OP via the second chamber 672 and the drain hole 653.

[0033] Furthermore, when the solenoid section 62 of the electromagnetic control valve 6 is energized ON, the rod 622 extends, as shown in Figure 5(b), causing the spool 612 to be biased toward the end wall 611b side against the biasing force of the biasing member 63. As a result, the inlet hole 650 communicates with the second supply / discharge hole 652 via the relay chamber 670, and the hydraulic fluid flowing from the main oil gallery MG into the inlet hole 650 is supplied to the advance-side working chamber P2 via the relay chamber 670 and the second supply / discharge hole 652. On the other hand, the first supply / discharge hole 651 communicates with the drain hole 653 via the first chamber 671 and the internal passage 664, and the hydraulic fluid flowing from the retard-side working chamber P1 into the first supply / discharge hole 651 is discharged to the oil pan OP via the first chamber 671, the internal passage 664 and the drain hole 653.

[0034] Figure 6 shows a cross-sectional view taken along line AA in Figure 3. Figure 7 shows a cross-sectional view taken along line BB in Figure 3.

[0035] For example, as shown in Figures 6 and 7, the introduction hole 650 of the electromagnetic control valve 6 is connected to a series of supply passages, a horizontal supply passage 71 and a vertical supply passage 72, which are located inside the cam carrier 2 and guide the hydraulic fluid, which is pumped from a main oil gallery (not shown) via an oil pump (not shown), to the valve housing 21.

[0036] The lateral supply passage 71 extends in the width direction of the internal combustion engine EG (cam carrier 2), with one end, the upstream side, communicating with the main oil gallery, and the other end, the downstream side, connected to the longitudinal supply passage 72. Here, as shown in Figure 7, for example, the lateral supply passage 71 is positioned offset to the front end side of the internal combustion engine EG (right side in Figure 7) relative to the valve housing 21 in the front-rear direction of the internal combustion engine EG, and is configured not to interfere with (connect to) the first and second longitudinal supply and discharge passages 731 and 732, which will be described later and extend along the cylinder axis Y direction.

[0037] The vertical supply passage 72 extends in the direction of the cylinder axis Y, with one end, the upstream end, connected to the downstream end of the horizontal supply passage 71, and the other end, the downstream end, connected to the introduction hole 650 in the valve housing 21. Here, the vertical supply passage 72 is formed by creating a straight through-hole 70 that passes through the valve housing 21 from outside the cam carrier 2, as shown in Figure 7, for example, and the outer end opening 720 that opens to the outside of the cam carrier 2 is closed via a sealing plug 8. In this way, the casting (casting mold) of the cam carrier 2 is simplified by forming the vertical supply passage 72 by machining.

[0038] Furthermore, the first intake / exhaust port 651 is connected to the retard-side operating chamber P1 via the first vertical intake / exhaust passage 731, the first horizontal intake / exhaust passage 741, the first annular groove 751, and the first shaft internal passage 761. The first vertical intake / exhaust passage 731 extends downward from the valve housing 21 along the cylinder axis Y direction. The first horizontal intake / exhaust passage 741 extends from the lower end of the first vertical intake / exhaust passage 731 toward the cam bracket 3 which constitutes the bearing portion of the camshaft 4 in the width direction of the cam carrier 2. The first annular groove 751 is continuously provided along the circumferential direction on the inner circumferential surface of the cam carrier 2 and cam bracket 3 which slide against the camshaft 4 in the bearing portion of the camshaft 4. The first shaft internal passage 761 extends along the internal axial direction (rotation axis X direction) of the camshaft 4, with one end opening into the first annular groove 751 and the other end opening into the retard-side operating chamber P1.

[0039] Similarly, the second intake / exhaust port 652 is connected to the advance-side operating chamber P2 via the second vertical intake / exhaust passage 732, the second horizontal intake / exhaust passage 742, the second annular groove 752, and the second shaft internal passage 762, which are provided parallel to the first vertical intake / exhaust passage 731, the first horizontal intake / exhaust passage 741, the first annular groove 751, and the first shaft internal passage 761. The second vertical intake / exhaust passage 732 extends downward from the valve housing 21 along the cylinder axis Y direction. The second horizontal intake / exhaust passage 742 extends in the width direction of the cam carrier 2 toward the cam bracket 3 which constitutes the bearing portion of the camshaft 4 from the lower end of the second vertical intake / exhaust passage 732. The second annular groove 752 is continuously provided along the circumferential direction on the inner circumferential surface of the cam carrier 2 and cam bracket 3 which slide against the camshaft 4 in the bearing portion of the camshaft 4. The second shaft internal passage 762 extends along the internal axial direction (rotation axis X direction) of the camshaft 4, with one end opening into the second annular groove 752 and the other end opening into the advance-side operating chamber P2.

[0040] (Effects of this embodiment) As described above, in the control valve mounting structure of the variable valve timing mechanism according to this embodiment, the boss portion 22 attached to the valve housing portion 21 protrudes upward (see Figure 2) toward the top dead center side of the cylinder axis Y than the solenoid portion 62 exposed from the valve housing portion 21. As a result, obstacles approaching the internal combustion engine EG from the cam carrier 2 side (above) collide with the boss portion 22, which is located on the cam carrier 2 side (above) the solenoid portion 62, thereby suppressing damage to the solenoid portion 62.

[0041] Furthermore, in this embodiment, the solenoid portion 62 is located in a region S on the cam carrier 2 side of the imaginary line V connecting the tip 220 of the boss portion 22 and the tip 230 of the flange portion 23 in the cylinder axis Y direction. Therefore, any obstacle approaching the internal combustion engine EG from the cam carrier 2 side (above) will primarily collide with the boss portion 22 and the flange portion 23. As a result, the boss portion 22 and the flange portion 23 work together to protect the solenoid portion 62 from obstacles approaching the internal combustion engine EG from the cam carrier 2 side (above).

[0042] Furthermore, in this embodiment, the boss portion 22 extends in the width direction of the internal combustion engine EG (cam carrier 2) along the extending direction of the valve housing portion 21. This allows the electromagnetic control valve 6 to be effectively protected along the extending direction of the valve housing portion 21.

[0043] Furthermore, in this embodiment, the lateral supply passage 71 allows hydraulic fluid to be guided from the main oil gallery to the valve housing 21 even if the valve housing 21 and the main oil gallery (not shown) are spaced apart. In addition, the vertical supply passage 72 allows hydraulic fluid to be guided from the lateral supply passage 71 to the introduction hole 650 of the spool valve 61 inside the valve housing 21. Moreover, by offsetting the vertical supply passage 72 so as not to interfere with the lateral supply passage 71, hydraulic fluid can be supplied to and discharged from each working chamber P1, P2 of the valve timing control device 5. Since the lateral supply passage 71, the vertical supply passage 72, and each vertical supply / discharge passage 731, 732 can all be formed by machining straight holes, good productivity of the cam carrier 2 can be ensured.

[0044] Furthermore, in this embodiment, the vertical supply passage 72 is formed to penetrate the valve housing 21 from the outside of the cam carrier 2, as shown in Figure 7. Therefore, when the internal combustion engine EG is positioned so that the cylinder axis Y is in the vertical direction, the upper end of the vertical supply passage 72, which is on the outer end side of the valve housing 21, is closed at the upper end (outer end opening 720) by the sealing plug 8, and the lower end is open to the valve housing 21. As a result, the accumulation of contaminants on the upper end side of the vertical supply passage 72 (between the outer end opening 720 and the valve housing 21) is suppressed, and malfunctions of the electromagnetic control valve 6 (spool valve 61) caused by the outflow of accumulated contaminants can be suppressed.

[0045] Furthermore, in this embodiment, the valve housing 21 is provided on a metal cam carrier 2 that supports the camshaft 4. By providing the valve housing 21 on the metal cam carrier 2 in this way, it becomes possible to attach the electromagnetic control valve 6 to the cam carrier 2 without providing any new metal parts, thereby reducing the number of parts in the internal combustion engine EG and simplifying its structure.

[0046] The present invention is not limited to the configurations illustrated in the above embodiments. For example, the specific shape of the cam carrier 2 other than the boss portion 22 and the flange portion 23, and the internal structure of the electromagnetic control valve 6, and other configurations not directly related to the features of the present invention can be freely modified according to the specifications of the internal combustion engine EG to which the present invention is applied. [Explanation of Symbols]

[0047] 1…Cylinder head 2…Cam carrier (cylinder head cover) 20…Cylinder head mounting surface 21... Valve housing 22... Boss section 23…Flange section 3… Cam bracket 4…Camshaft 5…Valve timing control device (variable valve train) 6… Solenoid control valve 61... Spool valve 62...Solenoid section 71... Lateral supply passage 72…Vertical supply passage 731...First longitudinal supply and drainage passage (longitudinal supply and drainage passage) 732...Second longitudinal supply and drainage passage (longitudinal supply and drainage passage) 8... Sealing plug 9…Front cover EG... Internal combustion engine Y...Cylinder axis

Claims

1. A control valve mounting structure for a variable valve timing mechanism, wherein an electromagnetic control valve for controlling the supply and discharge of hydraulic fluid to the variable valve timing mechanism is mounted on a cylinder head cover mounted on the cylinder head of an engine equipped with a variable valve timing mechanism, The aforementioned electromagnetic control valve is A spool valve is housed in a cylindrical valve housing located at the top of the cylinder head cover, and controls the supply and discharge of hydraulic fluid to the variable valve timing mechanism by switching the oil passage. A solenoid unit is attached to the opening of the valve housing and drives the spool valve, It has, The valve housing extends laterally, intersecting the cylinder axis, and has a boss portion on its side to which the solenoid portion is fixed. The boss portion is provided to protrude toward the top dead center in the direction of the cylinder axis, and protrudes further toward the top dead center than the solenoid portion, in a control valve mounting structure for a variable valve timing mechanism.

2. A control valve mounting structure for a variable valve timing mechanism according to claim 1, The valve housing is provided near the front cover located on the front end side of the engine. The front cover is fixed to the engine via a flange portion that protrudes toward the top dead center side from the front end of the cylinder head cover. The control valve mounting structure for a variable valve timing mechanism is such that the solenoid portion is located in a region on the cylinder head cover side of a virtual line connecting the tip of the boss portion that is furthest from the cylinder head mounting surface of the cylinder head cover and the tip of the flange portion that is furthest from the cylinder head mounting surface, in the direction of the cylinder axis.

3. A control valve mounting structure for a variable valve timing mechanism according to claim 2, The valve housing extends in the width direction of the engine, which is perpendicular to the axis of the engine's camshaft. The boss portion extends in the width direction of the engine along the extending direction of the valve housing portion, and is a control valve mounting structure for a variable valve timing mechanism.

4. A control valve mounting structure for a variable valve timing mechanism according to claim 3, The cylinder head cover is A lateral supply passage extending along the width direction of the engine, which guides hydraulic fluid from the main oil gallery, A vertical supply passage extending in the direction of the cylinder axis and connecting the valve housing and the lateral supply passage, A vertical supply and discharge passage is provided, which connects the valve housing and each operating chamber of the variable valve mechanism, and which supplies and discharges hydraulic fluid between the valve housing and the variable valve mechanism, with one end opening into the valve housing and extending in the direction of the cylinder axis. A control valve mounting structure for a variable valve timing mechanism, which has the following internally.

5. A control valve mounting structure for a variable valve timing mechanism according to claim 4, The aforementioned vertical supply passage is formed to penetrate the valve housing from the outside of the cylinder head cover, A control valve mounting structure for a variable valve timing mechanism, wherein the outer end of the vertical supply passage is closed by a sealing plug.

6. A control valve mounting structure for a variable valve timing mechanism according to claim 5, The cylinder head cover is a metal cam carrier that supports the camshaft in cooperation with a cam bracket mounted at the bottom, and is a control valve mounting structure for a variable valve timing mechanism.

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