JP2839672B2 - Engine valve timing control device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a valve timing control device for an engine in which a variable valve timing mechanism operated by hydraulic pressure is provided for a camshaft on a cylinder head.

[Conventional technology]

2. Description of the Related Art Conventionally, as shown in Japanese Utility Model Application Laid-Open No. 62-69005, a camshaft for opening / closing an intake / exhaust valve is disposed on a cylinder head. Is rotatably supported relative to the camshaft, and between the cam pulley and the camshaft,
2. Description of the Related Art There is known an engine in which a valve timing variable mechanism that changes valve timing (opening / closing timing of intake and exhaust valves) operated by hydraulic pressure to adjust valve timing according to an operating state is provided. . The variable valve timing mechanism includes, for example, a slide member (ring piston) meshing with a camshaft and a cam pulley, at least one of which is spirally meshed, and a hydraulic chamber for applying hydraulic pressure thereto. The slide member moves in the axial direction in response to the supply and discharge of hydraulic pressure, so that the relative phase between the cam pulley and the camshaft changes to change the valve timing.

The variable valve timing mechanism is provided with a passage, a control valve, and the like for supplying and discharging the hydraulic pressure. In the device disclosed in the above publication, the oil passing through the center of the camshaft through the hydraulic chamber is provided. A passage, a hydraulic supply passage for sending oil pumped by an oil pump to the oil passage, a relief passage for relieving oil from the oil passage, a relief amount control valve provided in the relief passage, and the like. ing.

[Problems to be solved by the invention]

In the above-described conventional apparatus, the hydraulic pressure supply passage is formed in the cylinder head below the camshaft, and the oil is guided from below to the oil passage of the camshaft. When air bubbles are mixed in the oil, the air bubbles are carried along with the oil from the hydraulic supply passage through the oil passage of the camshaft to the hydraulic chamber of the variable valve timing mechanism, and accumulate in the hydraulic chamber. In such a state, the responsiveness of the operation of the variable valve timing mechanism deteriorates due to the influence of the bubbles brought into the hydraulic chamber. Therefore, when the variable valve timing mechanism is controlled according to the operating state, there is a problem that a response delay occurs in the change in the valve timing with respect to the change in the operating state.

In the apparatus disclosed in the above publication, a relief amount control valve is disposed on the upper bearing with respect to the camshaft. However, this control valve only controls the relief amount of the relief passage, and the hydraulic pressure supply A function of removing air bubbles mixed in oil supplied from the use passage to the variable valve timing mechanism cannot be obtained.

In view of such circumstances, the present invention prevents bubbles from being carried into the variable valve timing mechanism even when bubbles are mixed in oil pumped from the oil pump, thereby improving the responsiveness of the variable valve timing mechanism. An object of the present invention is to provide an engine valve timing control device that can be improved.

[Means for solving the problem]

In order to achieve the above object, the present invention is provided with a variable valve timing mechanism that changes the valve timing by operating a hydraulic pressure on a camshaft disposed on a cylinder head, and communicates with the variable valve timing mechanism. In an engine in which an oil passage is provided in a camshaft, a control valve connected to the oil pressure supply passage and the oil passage to control supply of oil pressure to the variable valve timing mechanism is provided. It is configured to be disposed above the shaft arrangement portion.

When applied to an engine having a head cover that covers the camshaft, in the above configuration, the control valve is located above the head cover, and a pipe connecting the control valve and the oil passage passes through the head cover,
It is preferable that the space between the pipe and the head cover is sealed by a floating structure.

Further, in a structure in which a journal portion of a cam shaft is rotatably supported by a bearing portion of a cylinder head and a cam cap bolted to the bearing portion,
The control valve may be arranged above the cam cap, and the cam cap may be formed with an oil passage connecting the supply / discharge port of the control valve and an oil passage formed in the camshaft. The variable valve timing mechanism, for example, changes the relative phase between a cam pulley driven by a crankshaft and a camshaft, and is provided at an end of a camshaft protruding outside the engine body from the cam cap. Have been.

Further, the control valve is integrated with a member forming a bearing portion corresponding to a journal portion of the camshaft, and connects a supply / discharge port of the control valve to an oil passage formed in the camshaft. A configuration in which an oil passage is formed may be employed. For example, when a cam carrier that covers a cam shaft and integrally includes a bearing portion for a cam journal portion is applied to an engine mounted on a cylinder head, the control valve is integrally formed with a cam carrier that is a member that forms the bearing portion. It is preferable to adopt a built-in configuration.

As a configuration in which the control valve is integrated with the member forming the bearing portion, for example, a control valve holding portion is formed on the member forming the bearing portion, and the control valve is fitted into the control valve holding portion. Fixed.

The variable valve timing mechanism, for example, changes the relative phase between a cam pulley driven by a crankshaft and a camshaft, and the camshaft protrudes outside the engine body from a member forming the bearing portion. It is provided at the end.

[Action]

According to the device of the present invention, since the control valve connected to the hydraulic pressure supply passage is disposed above the camshaft arrangement portion, the oil supplied to the variable valve timing mechanism via the control valve is once cammed. It is carried upward from the shaft, where the air bubbles mixed into the oil are separated and sent to the variable valve timing mechanism.

In an engine in which the camshaft is covered with a head cover, the control valve may be located on the head cover,
In this case, the pipe penetrates through the head cover.However, by virtue of the configuration in which the space between the pipe and the head cover is sealed with a floating structure, oil leakage from the inside of the head cover is prevented and vibration is reduced. Transmission to the head cover is suppressed.

Also, in a member forming a bearing portion corresponding to a journal portion of a camshaft, for example, in an engine in which a cam carrier is mounted on a cylinder head, it is preferable that the control valve is integrally incorporated into the cam carrier. This is advantageous in terms of rigidity.

Example An example of the present invention will be described with reference to the drawings.

1 and 2 show an embodiment of the present invention. In these figures, a camshaft 2 is disposed on a cylinder head 1 and, for example, a pair of intake and exhaust camshafts 2 are arranged in parallel. Are located. Each camshaft 2
A plurality of journal portions 2a are provided, and the journal portion 2a is rotatably supported by a bearing portion of the cylinder head 1 and a cam cap 3 bolted thereto. The cams 2b provided on each camshaft 2 open and close the intake and exhaust valves 4 and 5 as the camshaft 2 rotates. Each of the camshafts 2 is covered with a head cover 6, and is usually attached to the cylinder head 1 via a gasket 7 having a vibration-proof property of the head cover 6 in order to prevent noise due to vibration of the head cover 6.

A cam pulley 8 driven by a crankshaft (not shown) via a timing belt or a chain is disposed at a camshaft end protruding outside the engine body from the cam cap 3, that is, at a front end side of the camshaft 2. A variable valve timing mechanism 10 is provided. The variable valve timing mechanism 10 operates according to the oil pressure and changes the valve timing by changing the relative phase between the cam pulley 8 and the camshaft 2. For example, a shaft fixed to the camshaft 2
11 and an outer cylindrical portion 12 having a cam pulley 8 are relatively rotatably connected to each other, and a slide member 13 is provided therebetween. The shaft portion 11 and the slide member 13 are connected by a spline, and The member 13 and the outer cylinder 12 are connected by a helical spline, so that the sliding member 13
, The relative phase between the cam pulley 8 and the camshaft 2 changes. The slide member 13 is urged in a certain direction by a spring 14 and a hydraulic chamber 15 is formed on one side of the slide member 13.
13 is to slide.

An oil passage 16 communicating with the hydraulic chamber 15 is formed at the center of a range extending from the vicinity of the journal portion 2a on one end side of the camshaft 2 to the shaft portion 11. Further, an oil introduction groove 17 is formed in the bearing portion of the cylinder head 1 and the cam cap 3 which support one end of the camshaft 2.
The oil introduction groove 17 and the oil passage 16 communicate with each other via a passage 18 formed in the radial direction of the camshaft 2.

A control valve 20 that controls supply of hydraulic pressure to the variable valve timing mechanism 10 is provided in a hydraulic path leading to the oil introduction groove 17. The control valve 20 is disposed above a portion where the camshaft 2 is disposed, and in this embodiment, is disposed on the head cover 6 above the cam cap 3. The lower end of the pipe 30 for connecting the control valve 20 and the oil passage 16 is fixed to the cam cap 3 while communicating with the oil introduction groove 17 and projects upward through the head cover 6. The control valve 20 is connected to the upper end of the pipe 30. The cam cap 3 is connected to the oil groove 16 by connecting the control valve 20 to the oil passage 16 via the pipe 30 by connecting the pipe 30 to the oil groove 17.
An oil passage that opens to the inner peripheral surface through the passage 30 is formed.

The space between the pipe 30 and the head cover 6 is sealed by a floating structure. For example, as shown in FIG. 2, a pipe insertion hole 31 having a larger diameter than the pipe 30 is formed in the head cover 6, and an elastic material such as rubber is used. Is mounted in the pipe insertion hole 31 in a state in which the seal member 32 is in close contact with the peripheral surface of the pipe 30 and the upper surface of the cam cap 3.

FIGS. 3A and 3B show a specific structure of the control valve 20. FIG. The control valve 20 includes a casing 21 having a hollow portion 21a in the center, a valve shaft 22 located in the casing 21 and capable of moving in the axial direction, and a spring for biasing the valve shaft 22 rearward. 23 and solenoid 24 to operate valve shaft 22
The energization of the solenoid 24 is controlled by a control circuit (not shown) in accordance with the operation state.

The casing 21 has an oil supply / discharge port 25 that opens near the front end (left end in the figure) of the hollow portion 21a, and an oil inflow port 26 that opens to the hollow portion 21a behind the oil supply / discharge port 26.
Further, an oil outflow port 27 that opens to the hollow portion 21a at the rear thereof, and a communication passage 28 that communicates the distal end side of the hollow portion 21a with the oil outflow port 27 are formed.
Are provided with two partition plates 22a and 22b in the axial direction. When the power is not supplied, the valve shaft 22 is in the retracted position as shown in FIG. 3 (a). In this state, the oil supply / discharge port 25 is cut off from the oil inflow port 26, and the oil When the solenoid 24 is energized and the solenoid 24 is energized, the valve shaft 22 is at a predetermined forward position as shown in FIG. 3 (b). In this state, the oil supply / discharge port 25 is connected. It is configured to be shut off from the passage 28 and communicate with the oil inflow port 26.

As shown in FIGS. 1 and 2, the oil supply / discharge port 25 is connected to a pipe 30 and communicates with an oil pressure chamber 15 of the variable valve timing mechanism 10 via an oil passage 16 and the like. The oil inflow port 26 is connected to a hydraulic pressure supply passage 33 communicating with an unillustrated oil pump, so that oil pumped by the oil pump is introduced into the oil inflow port 26. The oil outlet port 27 discharges oil to an appropriate place on the cylinder head 1.

The variable valve timing mechanism 10 and the oil passage and the control valve 20 for the variable valve timing mechanism 10 are provided for each of the intake and exhaust camshafts 2 in the example shown in FIGS. However, it may be provided only for one of the camshafts 2.

According to the apparatus of this embodiment, the control valve 20 is controlled in accordance with the operation state to supply and discharge oil to and from the variable valve timing mechanism 10, and the variable valve timing mechanism 10 is accordingly controlled. Operate. For example, when the control valve 20 is in the oil supply state as shown in FIG. 3 (b), the oil pumped by the oil pump passes through the control valve 20, passes through the pipe 30, the oil introduction groove 1
7. By being sent to the hydraulic chamber 15 of the variable valve timing mechanism 10 through the passage 18 and the oil passage 16, the slide member 13 receives the oil pressure and moves rightward in FIG.

When such oil supply is performed, bubbles may be mixed in the oil pumped from the oil pump to the hydraulic pressure supply passage 33. However, when the control valve 20 is mounted on the head cover 6 above the camshaft 2, By being disposed above, the oil is once carried upward and the control valve
After the air bubbles float at the portion where the 20 is located and are separated from the oil, the oil that has passed through the control valve 20 is sent to the variable valve timing mechanism 10. Therefore, the intrusion of bubbles into the hydraulic chamber 15 of the variable valve timing mechanism 10 is avoided, and the movement of the slide member 13 is performed with good responsiveness.

In the structure in which the camshaft 2 is covered with the head cover 6, the control valve 20 is positioned above the head cover 6 so as to have the above-described bubble separating action, and the control valve 20 is cammed by a pipe 30 penetrating the head cover 6. When connecting to the shaft supporting portion, it is necessary to ensure a sealing property between the pipe 30 and the head cover 6 in order to prevent oil leakage from inside the head cover 6.
When the head cover 6 and the head cover 6 are rigidly connected, the engine vibration is transmitted to the head cover 6 via the pipe 30 to generate vibration noise. On the other hand, a sealing member made of an elastic material
According to the present embodiment, the structure between the pipe 30 and the head cover 6 has a floating structure by means of 32, transmission of engine vibration to the head cover 6 is suppressed.

Note that the specific structure of the portion where the pipe 30 connecting the control valve 20 and the camshaft support portion passes through the head cover 6 is not limited to the above-described embodiment, and can be variously changed.
For example, as shown in FIG. 4, a gap is left between the pipe 30 and the periphery of the pipe insertion hole, and a sealing member made of an elastic material is provided between the upper surface of the cam cap 3 and the lower surface of the head cover 6 around the pipe 30. 5 or a sealing member 36 made of an elastic material as shown in FIG.
Even if it is mounted between the pipe 30 and the periphery of the pipe insertion hole in a state of being separated from the pipe 30, the pipe 30 and the space between the cam cap 3 and the head cover 6 are sealed in a floating structure.

FIG. 6 shows another embodiment of the present invention. In this embodiment, a cam carrier 40 (journal portion of a camshaft) which covers a camshaft 2 and integrally includes a bearing member corresponding to a plurality of cam journal portions 2a. In an engine having a structure in which a member forming a bearing portion corresponding to the cam carrier 40 is attached to the cylinder head 1, the control valve 20 is attached to the cam carrier 40.
Are integrated. That is, the control valve holding portion 41 is formed integrally with the upper portion of the cam carrier 40 on the front end side, and the control valve 20 is fitted into and fixed to the control valve holding portion 41. Further, the cam carrier 40 includes a camshaft 2
An oil introduction groove 17 communicating with the hydraulic chamber 15 of the variable valve timing mechanism 10 through the oil passage 16 is formed on the inner peripheral surface of the bearing portion, and the oil introduction groove 17 and an oil supply / discharge port of the control valve 20 are formed. A passage 42 communicating with 25 is formed. Further, a passage (not shown) for guiding the oil pumped from the oil pump to the oil inflow port 26 of the control valve 20 and a passage 43 leading to the oil outflow port 27 are also provided in the cam carrier.
The lower end of the passage 43 is open to the space inside the cam carrier 40.

According to this embodiment, the control valve 20 for controlling the supply of the hydraulic pressure to the variable valve timing mechanism 10 is
As a result, the rigidity of the control valve 20 is increased. Also in the case of this embodiment, since the control valve 20 is located above the camshaft 2, the operation of preventing the intrusion of bubbles into the hydraulic chamber 15 of the variable valve timing mechanism 10 is performed in the first embodiment. Obtained as in the example.

〔The invention's effect〕

As described above, according to the present invention, the control valve connected to the hydraulic pressure supply passage and controlling the supply of the hydraulic pressure to the variable valve timing mechanism is disposed above the camshaft arrangement portion. The supplied oil is once carried upward and bubbles are separated by the above-mentioned control valve, and the invasion of bubbles into the variable valve timing mechanism is avoided. Performance can be improved.

Further, the control valve is located above the head cover covering the camshaft, and a pipe connecting the control valve and the oil passage of the camshaft penetrates the head cover, and the pipe and the head cover are sealed by a floating structure. By so doing, when the control valve is arranged on the head cover, it is possible to prevent the vibration noise of the head cover from increasing while ensuring the sealing property between the pipe and the head cover.

Further, if a cam carrier that covers the cam shaft and integrally has a bearing portion for the cam journal portion is attached to the cylinder head, and the control valve is integrally incorporated in this cam carrier, the assembly rigidity is increased, It can improve durability and the like.

[Brief description of the drawings]

FIG. 1 is a partially cutaway plan view of a portion where a camshaft and a variable valve timing mechanism are arranged on a cylinder head in an apparatus according to an embodiment of the present invention, and FIG. FIGS. 3 (a) and 3 (b) are enlarged horizontal sectional views showing a specific structure of the control valve, and FIGS. 4 and 5 are drawings of a floating structure between a pipe connected to the control valve and a head cover, respectively. FIG. 6 is a longitudinal sectional side view showing another embodiment of the apparatus of the present invention. 1 ... Cylinder head, 2 ... Camshaft, 6 ... Head cover, 10 ... Variable valve timing mechanism, 16 ...
Oil passage, 20 ... Control valve, 30 ... Pipe, 31, 35, 36 ...
... Seal member, 33 ... Hydraulic supply passage, 40 ... Cam carrier.

──────────────────────────────────────────────────続 き Continued on the front page (56) References JP-A-61-201804 (JP, A) JP-A-55-43295 (JP, A) JP-A-54-121314 (JP, A) JP-A-3- 249315 (JP, A) Japanese Utility Model 62-69005 (JP, U) Japanese Utility Model Application 1-103706 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) F01L 1/34 F01L 13 / 00 301 F01L 1/04

Claims (8)

(57) [Claims] A variable valve timing mechanism which is actuated by hydraulic pressure to change a valve timing with respect to a camshaft disposed on a cylinder head; and an oil passage communicating with the variable valve timing mechanism is provided in the camshaft. An engine having a control valve connected to the oil pressure supply passage and the oil passage for controlling supply of oil pressure to the variable valve timing mechanism, and the control valve is disposed above the camshaft arrangement portion. A valve timing control device for an engine, comprising: 2. The control valve is located above a head cover that covers the camshaft, a pipe connecting the control valve and the oil passage penetrates the head cover, and a space between the pipe and the head cover has a floating structure. 2. The valve timing control device for an engine according to claim 1, wherein the valve timing control device is sealed. 3. A journal portion of a camshaft is rotatably supported by a bearing portion of a cylinder head and a cam cap bolted to the bearing portion, and the control valve is disposed above the cam cap. 3. The engine valve timing control device according to claim 1, wherein an oil passage connecting the supply / discharge port of the control valve and an oil passage formed in the camshaft is formed in the cam cap. . 4. A variable valve timing mechanism for changing a relative phase between a cam pulley driven by a crankshaft and a camshaft, and is provided at an end of the camshaft protruding outside the engine body from the cam cap. The valve timing control device for an engine according to claim 3, wherein: 5. The control valve is integrated with a member forming a bearing portion corresponding to a journal portion of a camshaft, and a supply / discharge port of the control valve and an oil passage formed in the camshaft are provided. The valve timing control device for an engine according to claim 1, wherein an oil passage connecting the valve timing is formed. 6. A member forming the bearing portion is a cam carrier that covers a cam shaft and integrally includes a bearing portion for a cam journal portion. The cam carrier is mounted on a cylinder head, and the control valve is integrated with the cam carrier. 6. The valve timing control device for an engine according to claim 5, wherein the valve timing control device is integrated. 7. The control valve according to claim 5, wherein a control valve holding portion is formed on a member forming the bearing portion, and the control valve is fitted into and fixed to the control valve holding portion. Engine valve timing control device. 8. A variable valve timing mechanism for changing a relative phase between a cam pulley driven by a crankshaft and a camshaft, wherein the camshaft protrudes outside the engine main body from a member forming the bearing portion. The valve timing control device for an engine according to any one of claims 5 to 7, wherein the valve timing control device is provided at an end.