JP3431810B2 - Intake and exhaust valve drive control device for internal combustion engine - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake / exhaust valve drive control device for variably controlling the opening / closing timing of an intake valve / exhaust valve in accordance with the operating state of an internal combustion engine for an automobile.

[0002]

2. Description of the Related Art Conventionally, various types of devices for variably controlling the opening / closing timings and operating angles of intake / exhaust valves have been provided. One of them is, for example, Japanese Utility Model Publication 57-198.
As described in Japanese Patent Application Laid-Open No. 306 and Japanese Patent Application Laid-Open No. 6-185321, those applying the principle of a non-constant velocity shaft coupling are known. This is because a cylindrical cam shaft divided for each cylinder is rotatably provided on the outer periphery of a drive shaft that rotates in synchronization with the rotation of the engine, and a flange portion at the end of the cam shaft and the drive shaft side. And a pair of pins that engage with the respective engaging grooves are provided on the annular disc interposed between the flange portions. The disc is rotatably held by the control housing, and the annular disc can be eccentric with respect to the camshaft via the control housing. By controlling the eccentricity, the valve lift characteristic is changed. It is supposed to do.

Here, as an operating mechanism for moving the control housing in the direction perpendicular to the axis, one shown in FIG. 5 is known. The operating mechanism includes a control shaft 100 linked to a control housing (not shown), and the control shaft 100.
A hydraulic cylinder 102 that is connected to the
A hydraulic circuit 103 for supplying and discharging hydraulic pressure to and from the pressure chamber of the hydraulic cylinder 102, and a switching valve 105 for switching the oil passage of the hydraulic circuit 103 according to the engine operating state. Of these, the control shaft 100 is rotatably supported on an upper portion of a cylinder head (not shown), and is rotated by the hydraulic cylinder 102 to move the control housing in a direction perpendicular to the axis. The operating mechanism detects the rotation angle of the control shaft 100 by the sensor 106, inputs the detection signal to the controller 107, and operates the switching valve 105 by the controller 107 to control the operation of the hydraulic cylinder 102. However, the rotation angle of the control shaft 100 is controlled (see Japanese Patent Laid-Open No. 7-196256).

[0004]

However, in such an intake / exhaust valve drive control device, as shown in FIG. 5, the hydraulic cylinder 102, the hydraulic circuit 103, and the switching valve 105 are not shown in FIG. Since the hydraulic cylinder 102, the hydraulic circuit 103, and the switching valve 105 were to be attached to the outside of the partition wall of the head and exposed to the outside of the cylinder head, a large space must be secured around the cylinder head. did not become.

Further, in the above-mentioned conventional technique, as shown in FIG.
The hydraulic circuit 103 and the switching valve 105 are connected to the hydraulic cylinder 102.
Since it was arranged so as to be orthogonal to the operating direction of, the oil passage structure of the hydraulic circuit 103 was complicated. Therefore, it has been desired to provide an intake / exhaust valve drive control device that can simplify the oil passage structure of the hydraulic circuit 103.

Further, as shown in FIG. 5, the above-mentioned prior art is as follows.
Hydraulic cylinder 102, hydraulic circuit 103, and switching valve 105
Is attached to the outside of the partition wall of the cylinder head (not shown) via the support plate 109, and since the force acting in the direction of peeling the support plate 109 from the cylinder head is large, the cylinder head of the support plate 109 is The mounting strength of
Further, there is a problem that oil leakage may occur unless the seal between the support plate 109 and the cylinder head is strictly tightened.

Therefore, an object of the present invention is to provide an intake / exhaust valve drive control device for an internal combustion engine, which is capable of solving the above-mentioned problems of the prior art.

[0008]

According to the present invention, there is provided a drive shaft, which is rotatably supported by a cylinder head, and which rotates in synchronization with the rotation of an engine, and a relatively rotatable outer periphery of the drive shaft. together are divided for each cylinder, a cylindrical cam shaft having a cam for driving the intake and exhaust valves on the outer periphery, sheet
It is placed parallel to the drive shaft above the Linda head and
A control shaft that has an eccentric cam and is rotatably supported
And by rotating the control shaft,
A variable mechanism that changes the operating angle of the exhaust valve, a hydraulic cylinder that is connected to the control shaft and rotates the control shaft, a hydraulic circuit that supplies and discharges hydraulic pressure to and from the hydraulic cylinder, and an oil passage of the hydraulic circuit. And a support plate for mounting the hydraulic cylinder, the hydraulic circuit, and the switching valve on the cylinder head,
Is equipped with. The present invention is characterized in that the support plate is attached to the upper part of the cylinder head, and the hydraulic cylinder is arranged on the upper side of the cylinder head which is closed by the support plate and the cylinder head cover.

Further, according to the present invention, the hydraulic cylinder is supported by the above.
Inside the holding plate, the hydraulic circuit is provided with the supporting plate.
On the outside of, while being arranged, the hydraulic circuit is attached to the support plate so as to face the hydraulic cylinder across the support plate, the hydraulic
The switching valve is attached to the circuit .

Further, the present invention is characterized in that a hole for connecting the control shaft and the hydraulic cylinder is formed in the support plate.

Further, in the present invention, the hydraulic circuit includes a plurality of oil passages for selectively communicating the pressure chamber defined by the piston of the hydraulic cylinder and the hydraulic source through the switching valve, and these oil passages. And a drain oil passage for selectively communicating the cylinder head internal space with the switching valve. Further, the drain oil passage is arranged in the hydraulic circuit so as to be located above the respective oil passages when the cylinder head is mounted on the vehicle.

Further, the present invention is characterized in that an opening end of the piston rod hole of the hydraulic cylinder is located above a pressure chamber defined by a piston of the hydraulic cylinder when the cylinder head is mounted on a vehicle. .

[0013]

According to the present invention, the support plate is attached to the upper portion of the cylinder head, and the hydraulic cylinder is arranged on the upper side of the cylinder head which is closed by the support plate and the cylinder head cover. Compared to the conventional example in which the cylinder is projected to the outside of the cylinder head, the number of parts protruding to the outside of the cylinder head is reduced, and it is not necessary to secure a large space around the cylinder head. Therefore, according to the present invention, the space in the engine room of the vehicle can be effectively used.

Further, according to the present invention, since the hydraulic circuit is attached to the support plate so as to face the hydraulic cylinder with the support plate interposed therebetween , the hydraulic structure can be simplified. In addition, according to the present invention, as described above, the hydraulic cylinder is arranged on the upper side of the cylinder head which is closed by the support plate and the cylinder head cover, and the hydraulic circuit and the switching valve are arranged with the support plate interposed therebetween. Since the load acting on the plate is balanced, the mounting strength of the support plate to the cylinder head should be reduced compared to the conventional example in which the hydraulic cylinder, hydraulic circuit and switching valve were all mounted on one side of the support plate. You can Furthermore,
Since the support plate can be securely attached to the cylinder head, the seal between the support plate and the cylinder head becomes easy.

Further, according to the present invention, since the work of connecting the control shaft and the hydraulic cylinder can be performed by utilizing the hole formed in the support plate, the work of assembling the intake / exhaust valve drive control device can be easily performed. You can

Further, according to the present invention, when the cylinder head is mounted on the vehicle, the drain oil passage is arranged above the other oil passages in the hydraulic circuit. It is possible to prevent the oil from leaking to the outside through the drain oil passage.

Further, according to the present invention, when the cylinder head is mounted on the vehicle, the opening end of the piston rod hole of the hydraulic cylinder is located above the pressure chamber of the hydraulic cylinder, so that the hydraulic cylinder is stopped when the engine is stopped. It is possible to prevent oil inside from leaking out from the piston rod hole.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an exploded perspective view showing an embodiment of an intake / exhaust valve drive control device according to the present invention, and FIG. 2 is a view taken in the direction of arrow A in FIG.

As shown in FIGS. 1 and 2, a drive shaft 1 which is continuous over all cylinders is disposed above the cylinder head S. The drive shaft 1 is hollow and has a lubricating oil passage (not shown) formed therein. A sprocket 2 is attached to one end of the drive shaft 1 and is interlocked with a crankshaft (not shown) via a tamping chain 3. is doing. A cylindrical camshaft 5 divided for each cylinder is fitted on the outer periphery of the drive shaft 1 so as to be relatively rotatable.
A first flange portion 6 is provided at the end of each camshaft 5. Each camshaft 5 has, for example, a pair of cams 5a for driving the intake valve 7, and an intermediate journal portion 5b of the pair of cams 5a has a partition wall-shaped cam bracket mounting portion on the cylinder head side (not shown). It is rotatably supported between a semi-circular bearing surface recessed in and a cam bracket (not shown).

A short sleeve 9 is fixed to the drive shaft 1, and a second flange portion 10 is provided at an end portion of each sleeve 9 so as to face the first flange portion 6 respectively.
Are formed. An annular disc 11 having an annular shape is interposed between the flange portions 6 and 10, and the annular disc 11 is rotatably fitted and held in a circular opening 12 a of the control housing 12. There is. Specifically, the inner peripheral surface of the opening 12a of the control housing 12 is a simple cylindrical surface, and the outer peripheral surface of the annular disk 11 is rotatably fitted to the inner peripheral surface of the annular disk 11 via a bearing 13.

The first flange portion 6 and the second flange portion 10 have engaging grooves 15 and 1 extending in the radial direction, respectively.
6 is formed. Both engaging grooves 15 and 16 are 1
They are arranged at different positions by 80 degrees. The holding holes 17 and 18 are formed in the annular disk 11 at positions different from each other by 180 °, and the first pin 20 and the second pin 21 are rotatably fitted in the holding holes 17 and 18, respectively. These pins 20 and 21 project in directions opposite to each other, and the tip portion of the first pin 20 has the first flange portion 6
Is slidably engaged with the engaging groove 15 of the second
The tip portion of the pin 21 is slidably engaged with the engagement groove 16 of the second flange portion 10. The side surfaces of the tips of the pins 20 and 21 that are in sliding contact with the engagement grooves 15 and 16 are processed into a pair of parallel planes.

The eccentric type variable valve mechanism itself as described above has a known construction, for example, in the above-mentioned Japanese Patent Laid-Open No. 6-185321, so a detailed description thereof will be omitted, but the annular disk 11 is driven. When the camshafts 5 are located concentrically with respect to the center of the shaft 1, each camshaft 5 rotates at a constant speed with respect to the drive shaft 1, and valve lift characteristics along the profile of the cam 5a are obtained. Further, when the annular disk 11 is eccentric with respect to the center of the drive shaft 1, it becomes a kind of non-constant velocity shaft coupling, and each cam shaft 5 rotates at a non-constant velocity with respect to the drive shaft 1. As a result, the valve lift characteristic and the valve operating angle change according to the amount of eccentricity.

The control housing 12 for rotatably holding the annular disk 11 is a plate-like member along a plane orthogonal to the drive shaft 1. In the upper part of the control housing 12, an engagement groove 22 that opens upward in FIG. A control shaft 23 is provided in parallel with the drive shaft 1 so as to pass through the engagement grooves 22. Specifically, the eccentric cam 25 of the control shaft 23 is engaged with the engagement groove 22 of the control housing 12 via the block 26. And the control housing 1
2, a circular support hole 27 is formed on the lower left side in FIG. 2, and a support shaft 29 is inserted into the circular support hole 27. The control housing 12 is the support shaft 2
9 is used as a support portion (swing center) and can be swung around the support shaft 29. Here, the control housing 12, the annular disk 11, the bearing 13,
The flange portions 6 and 10 provided with the pins 20 and 21 and the engagement grooves 15 and 16 move concentrically or eccentrically with respect to the shaft center of the drive shaft 1 so that the relative angular velocity between the drive shaft 1 and the cam shaft 5 is increased. A variable mechanism 28 that variably controls the operating angle of the intake / exhaust valve by changing the operation angle is configured. The support shaft 29 is divided for each cylinder, and is supported by the cylinder head S via a support portion (not shown).

The block 26 includes a first block member 26a on the left side in FIG. 2 and a second block member 2 on the right side in FIG.
6b and 6b. The first and second block members 26a and 26b are substantially semicircular cam receiving portions 27a and 27b that rotatably support the eccentric cam 25.
The eccentric cam 25 is sandwiched from both sides, and the engaging groove 2
2 can be slid vertically along the wall surfaces 28a and 28b in FIG.

The control shaft 23 is rotatably supported between a cam bracket 32 and a semicircular bearing surface 31 recessed in the cam bracket mounting portion 30 on the cylinder head S side. 1 is continuous in parallel with all cylinders, and one end (rear end) thereof is connected to the tip of a piston rod 36 of a hydraulic cylinder 35 via an arm 33. Here, the arm 33 is positioned with respect to the control shaft 23 by inserting a pin 39 into a hole 37 formed on its side surface and fitting the pin 39 into a hole (not shown) on the control shaft 23 side. After that, it is fixed to the end of the control shaft 23 with a bolt 40. or,
The arm 33 is configured such that the width across flat portion 42 of the piston rod 36 is inserted into the rod mounting groove 41 of the arm 33, and the pin engages with the slit 43 of the arm 33 and the hole 45 at the tip of the piston rod 36. It is connected to the hydraulic cylinder 35 by 46.

The hydraulic cylinder 35 is arranged on a support plate 47 fixed to the upper part of the rear end of the cylinder head S, and its operating direction is orthogonal to the control shaft 23. The support plate 47 includes a partition wall 49 extending in a direction orthogonal to the control shaft 1, and side walls 50 and 51 integrally formed at both ends of the partition wall 49 and extending toward the front of the cylinder head S.
The upper portions of the side walls 50 and 51 are formed so that a cylinder head cover (not shown) can be fixed. Further, the hydraulic cylinder 35 is provided inside the one side wall 50 of the support plate 47.
Are arranged. In this hydraulic cylinder 35, the cylinder 52 has a partition wall 49 inside the side wall 50 of the support plate 47.
The piston rod 36 is inserted through a cylinder hole 53 that is integrally formed on the front side of the side wall 50. That is, the hydraulic cylinder 35 is arranged inside the cylinder head S which is closed by the support plate 47 and the cylinder head cover (not shown). Here, the hydraulic cylinder 35 is arranged on the exhaust valve side when the variable mechanism 28 (control housing 12, annular disc 11, etc.) is arranged on the intake valve side, and the variable mechanism is arranged on the exhaust valve side. If so, it is arranged on the intake valve side. A piston 55 is formed at the end of the piston rod 36 to define the interior of the cylinder 52 into two chambers, and a piston ring 56 is fitted to the outer periphery of the piston 55. . The cylinder hole 53 is sealed by a seal member 59 and a lid member 60 which are fixed to the side wall 50 with bolts 57.

A hydraulic circuit 61 is provided on the rear side of the partition wall 49 of the support plate 47 and at a portion facing the hydraulic cylinder 35.
Are fixed with bolts 63 via gaskets 62. The hydraulic circuit 61 includes a plurality of oil passages 65 and 66 and a drain oil passage 67 (see FIG. 4). A switching valve 69 for switching the oil passages 65, 66, 67 is fixed to the hydraulic circuit 61 with a bolt 70.

The switching valve 69 is an electromagnetic valve that operates based on a control signal from a controller (not shown) to switch between the oil passages 65 and 67, and is arranged in parallel with the hydraulic cylinder 35. However, as shown in FIG. 3, the switching valve 69 is arranged so that the switching cylinder 69 is not located on the extension of the central axis of the hole 71 formed in the partition wall 49 of the support plate 47.
Is attached to the hydraulic circuit 61 at a predetermined angle Θ with respect to the operating direction. Hole 7 in partition 49 of support plate 47
Reference numeral 1 denotes a working hole which is located on the extension of the center line of the control shaft 23 and which connects the control shaft 23 and the piston rod 36 of the hydraulic cylinder 35. That is, the holes 71 of the partition wall 49 of the support plate 47 are, as shown in FIG.
When fixing the arm 33 to the control shaft 23, the bolt 40 can be tightened from the outer side (rear side) of the support plate 47, and the work of connecting the control shaft 23 and the hydraulic cylinder 35 can be easily performed. It is possible to efficiently perform the assembly work of the valve drive control device. In addition, as shown in FIG. 3, by tilting the switching valve 69 by a predetermined angle Θ with respect to the operating direction L of the hydraulic cylinder, the control shaft 23 can be rotated from the hole 71 of the partition wall 49 of the support plate 47. Therefore, the operation check of the intake / exhaust valve drive control device at the time of assembling the engine or at the time of maintenance can be performed using the hole 71 of the partition wall 49 of the support plate 47.

The hydraulic circuit 61 has an oil passage 65, which communicates with hydraulic ports 72 and 73 formed in the hydraulic cylinder 35.
66 and a drain oil passage 67 communicating with a drain port 74 formed in the partition wall 49 of the support plate 47 (see FIG. 4). The oil passages 65 and 66 are provided by a switching valve 69 to a hydraulic pump (not shown). ) Or the drain oil passage 67 is selectively communicated. As a result, the pressure chambers 76, 7 defined by the piston 55 of the hydraulic cylinder 35
7 is selectively communicated with the hydraulic pump side (not shown) or the drain oil passage 67 side, and the hydraulic pressure is supplied to and discharged from the hydraulic cylinder 35.

Further, as shown in FIG. 4, the hydraulic circuit 61 is formed such that the drain oil passage 67 is located above the other oil passages 65 and 66 when the engine is mounted on the vehicle. Therefore, when the engine is stopped, the oil in the pressure chambers 76, 77 of the hydraulic cylinder 35 does not leak through the drain oil passage 67. In FIG. 4, H is a horizontal line when the engine is installed in the vehicle.

Further, as shown in FIG. 4, the hydraulic cylinder 35 has a rod guide 7 when the engine is mounted on a vehicle.
The opening end 81 of the piston rod hole 80 formed in 9 is formed above the pressure chambers 76 and 77 defined by the piston 55. Therefore, when the engine is stopped, the oil in the pressure chambers 76, 77 of the hydraulic cylinder 35 will not leak out through the piston rod hole 80 of the rod guide 79.

Incidentally, as shown in FIG.
A sensor 83 for detecting the rotation speed of the cam 82 is attached to the other side wall 51 side.

In this embodiment having such a configuration, the oil passages 65 and 66 of the hydraulic circuit 61 are selectively communicated with the hydraulic pump or drain oil passage 67 (not shown) by the switching valve 69, and The hydraulic pressure is supplied to and discharged from the piston rod 36, and the control shaft 2 is moved through the arm 33.
When the 3 rotates, the control housing 12 moves the support shaft 2
The center of the annular disk 11 is decentered from the centers of the drive shaft 1 and the camshaft 5 by a predetermined amount.

As described above, in this embodiment, the support plate 47 is attached to the upper rear end of the cylinder head S, and the inside (front side) of the partition wall 49 of the support plate 47.
The hydraulic cylinder 35 is arranged in the
A hydraulic circuit 61 is arranged at a position facing the hydraulic cylinder 35 on the outer side (rear side) of the partition wall 49 of the hydraulic circuit 6.
1, the switching valve 69 is attached. Therefore, according to the present embodiment, as compared with the conventional example (see FIG. 5) in which the hydraulic cylinder 100, the hydraulic circuit 101, and the switching valve 102 are all arranged outside the support plate 103, the cylinder head S is located outside the cylinder head S. The number of protruding parts is reduced, and it is not necessary to secure a large space around the cylinder head S.

Further, in this embodiment, the support plate 4 is
7, the hydraulic cylinder 35 is arranged inside the partition wall 49 (front side), while the hydraulic circuit 6 is provided outside the partition wall 49 (rear side) of the support plate 47 at a position facing the hydraulic cylinder 35.
1 is arranged and the switching valve 69 is attached to the hydraulic circuit 61, the weight is balanced inside and outside (front and rear) of the partition wall 49, and the attachment strength of the support plate 47 to the cylinder head S is higher than that of the conventional example. Can also be smaller.
Further, as described above, the load acting on the inside and outside of the support plate 47 is balanced, and the support plate 47 can be securely attached to the cylinder head S. Therefore, a seal between the support plate 47 and the cylinder head S is achieved. It can be done easily.

Further, in the present embodiment, the hydraulic cylinder 35 is arranged inside the support plate 47, and the support plate 47 is
The hydraulic circuit 6 is provided on the outer side of the cylinder facing the hydraulic cylinder 35.
1 is arranged and the switching valve 69 is attached to the hydraulic circuit 61 so as to be parallel to the hydraulic cylinder 35, the oil passage structure of the hydraulic circuit 61 can be simplified.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of an intake / exhaust valve drive control device for an internal combustion engine showing an embodiment of the present invention.

FIG. 2 is a view on arrow A in FIG.

FIG. 3 is a main part assembly view seen from the direction B in FIG. 1;

FIG. 4 is a sectional view of the hydraulic cylinder taken along the line C-C in FIG. 1.

FIG. 5 is a perspective view of a conventional main part.

[Explanation of symbols]

S ... Cylinder head 1 ... Drive shaft 5 ... Cam shaft 5a ... Cam 23 ... Control shaft 28 ... Variable mechanism 35 ... Hydraulic cylinder 47 ... Support plate 55 ... -Piston 61 ... Hydraulic circuits 65, 66 ... Oil passage 67 ... Drain oil passage 69 ... Switching valve 71 ... Holes 76, 77 ... Pressure chamber 80 ... Piston rod hole 81 ... Open end

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akira Hidaka Address 1370 Onna, Atsugi City, Kanagawa Prefecture, Unisia Jex Co., Ltd. (56) Reference JP-A-9-41922 (JP, A) JP-A-8-260923 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) F01L 13/00 301 F01L 1/34 F02F 1/24

Claims (4)

(57) [Claims] 1. A rotatably supported by a cylinder head,
A drive shaft that rotates in synchronism with the rotation of the engine, and a cylindrical shape that is relatively rotatably provided on the outer periphery of the drive shaft and is divided into cylinders, and that has a cam that drives the intake and exhaust valves on the outer periphery. A cam shaft, a control shaft that is arranged above the cylinder head in parallel with the drive shaft, and has an eccentric cam on the outer periphery and is rotatably supported. By rotating the control shaft, A variable mechanism that changes the operating angle, a hydraulic cylinder that is connected to the control shaft to rotate the control shaft, a hydraulic circuit that supplies and discharges hydraulic pressure to and from the hydraulic cylinder, and an oil passage of the hydraulic circuit that operates the engine. A switching plate that switches according to the state; and a support plate that mounts the hydraulic cylinder, the hydraulic circuit, and the switching valve to the cylinder head, wherein the support plate is the cylinder. Attached to the top of the head, the intake and exhaust valves drive control device of the support plate and the cylinder head cover and the internal combustion engine in which the hydraulic cylinder is disposed on the cylinder head upper side to be closed by, the hydraulic cylinder of the support plate Inside, the above oil
The pressure circuits are arranged on the outside of the supporting plate, respectively.
In addition, the hydraulic circuit is attached to the support plate so as to face the hydraulic cylinder with the support plate interposed therebetween, and the switching valve is attached to the hydraulic circuit . Intake and exhaust valve drive control device. 2. The intake / exhaust valve drive control device for an internal combustion engine according to claim 1, wherein a hole for connecting the control shaft and the hydraulic cylinder is formed in the support plate. 3. The hydraulic circuit includes a plurality of oil passages for selectively communicating a pressure chamber defined by a piston of the hydraulic cylinder with an oil pressure source via the switching valve, and the oil passages and the inside of the cylinder head. A drain oil passage that selectively communicates with the space via the switching valve, wherein the drain oil passage is positioned above each oil passage when the cylinder head is mounted on a vehicle. The intake / exhaust valve drive control device for an internal combustion engine according to claim 1, wherein the intake / exhaust valve drive control device is arranged. 4. The piston rod hole opening end of the hydraulic cylinder is located above a pressure chamber defined by the piston of the hydraulic cylinder when the cylinder head is mounted on a vehicle. Intake and exhaust valve drive control device for internal combustion engine.