JP5316812B2 - Engine with variable valve system - Google Patents

Description

  The present invention relates to an engine including a cam phase variable mechanism capable of changing a cam phase.

In recent years, an engine equipped with a cam phase variable mechanism has been increasing as a variable valve operating device that changes the valve opening / closing timing (cam phase). Furthermore, a technique has been developed in which the cam phase variable mechanism is employed in an engine having a plurality of valves in one cylinder, and the opening / closing timing of only a part of the plurality of valves is changed according to the operating state of the engine.
A camshaft used for such a valve gear of an engine is assembled by fitting a separate cam crest to a shaft member so as to be rotatable. The cam phase variable mechanism is, for example, a hydraulically driven actuator such as a vane actuator, and is arranged at the end of the cam shaft. By changing the phase between the shaft member and the cam crest, a plurality of cam phase variable mechanisms can be used. It is possible to change the split of the valves so that the phases of some valves and other valves can be changed (Patent Document 1).

JP 2009-144521 A

By the way, in the cam phase variable mechanism constituted by the hydraulically driven actuator as described above, there is a risk that hydraulic oil leaks from the main body due to its structure. Therefore, it is necessary to store the cam phase variable mechanism in a closed space to prevent leakage of hydraulic oil to the outside.
However, if the cam phase variable mechanism is stored in a closed space, the hydraulic oil is stored in the storage portion, and the cam phase variable mechanism may be immersed in the hydraulic oil. When the cam phase variable mechanism is immersed in the hydraulic oil in this way, especially when the amount of hydraulic oil in the storage portion is large, the friction increases due to the increase in the hydraulic oil agitation resistance due to the rotation of the cam phase variable mechanism. However, there is a possibility that the engine performance deteriorates or aeration occurs due to agitation and the responsiveness of the cam phase variable mechanism decreases.

  The object of the present invention is to suppress the accumulation of hydraulic oil in the storage portion of the cam phase variable mechanism, reduce the friction in the cam phase variable mechanism, improve the engine performance, and improve the response of the cam phase variable mechanism. An object of the present invention is to provide an engine with a variable valve operating device that is improved.

In order to achieve the above object, the invention of claim 1 is provided at one end of the camshaft, and is a hydraulically driven cam phase variable mechanism that varies the phase of the valve drive cam, and a housing that houses the cam phase variable mechanism. A variable valve gear engine, and a space inside the storage portion that is separated from the space for storing the valve in the cylinder head by a partition, and the cam phase variable mechanism in the space The partition wall is formed with an oil passage that communicates the space in the storage portion with the space in the cylinder head, and the inner wall of the storage portion is filled with hydraulic oil in the storage portion by using the rotation of the cam phase variable mechanism. An introduction means for guiding the cylinder head is provided .

According to a second aspect of the present invention, in the first aspect, the variable cam phase mechanism has a cylindrical outer shape and is arranged coaxially with the cam shaft, and the inner wall of the storage portion extends along the outer periphery of the variable cam phase mechanism. It is characterized by being formed in an arc shape .

Further, the invention of claim 3 is the storage device according to claim 1 or 2, wherein the upper portion of the storage portion is opened and the internal space is formed in a semi-cylindrical shape, covers the lower half of the cam phase variable mechanism, and the upper portion of the storage portion. Is covered with a cylinder head cover having an inner wall formed in an arc shape along the outer periphery of the cam phase varying mechanism.
According to a fourth aspect of the present invention, in any one of the first to third aspects, the storage portion is formed separately from the cylinder head and is fixed to the cylinder head.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the control valve for controlling the operation of the cam phase variable mechanism is fixed to the storage portion, and the drain oil passage of the control valve opens to the space in the cylinder head. It is characterized by that.
According to a sixth aspect of the present invention, in the fourth aspect of the present invention, the storage unit is provided with detection means for detecting the phase of the cam variably controlled by the cam phase variable mechanism.

According to the engine with a variable valve operating apparatus of the first aspect of the present invention, since the cam phase variable mechanism is stored in the storage portion, even if the hydraulic oil leaks from the cam phase variable mechanism, the hydraulic oil flows out to the outside. Can be prevented. And since the oil passage which connects the space in the storage part and the space in the cylinder head is formed in the partition wall, the hydraulic oil leaking into the storage part is discharged into the space in the cylinder head, and the hydraulic oil in the storage part is discharged. Storage can be suppressed. Therefore, when the cam phase variable mechanism is operated, friction due to agitation of the hydraulic oil in the storage portion can be reduced, and variable responsiveness by the cam phase variable mechanism can be improved.
Further, since the operating oil in the storage portion stirred by the rotation of the cam phase variable mechanism is guided to the oil passage by the introducing means, the operating oil can be smoothly discharged from the oil passage. Therefore, the storage of the hydraulic oil can be quickly eliminated, and the stirring resistance of the hydraulic oil can be quickly reduced.

  According to the engine with a variable valve device of claim 2 of the present invention, since the inner wall of the storage portion is formed in an arc shape along the outer shape of the cam phase variable mechanism, the hydraulic oil is stored in the storage portion. However, when the cam phase variable mechanism rotates, the hydraulic oil in the storage portion is smoothly stirred, and an increase in friction can be suppressed. In addition, since the aeration can be suppressed by smooth agitation of the hydraulic oil, when the hydraulic oil in the storage part is recovered and reused as the hydraulic oil for the cam phase variable mechanism, the hydraulic oil pressure decreases due to aeration. Can be suppressed, and a decrease in the operation response of the cam phase varying mechanism can be prevented. Further, since it is formed in an arc shape, the shape of the storage portion can be reduced, and a compact design is possible.

According to the engine with a variable valve operating device of the third aspect of the present invention, the entire circumference of the cam phase varying mechanism can be covered with a relatively small gap inside by combining the cylinder head cover and the storage portion. Therefore, it is possible to store the cam phase variable mechanism housing in which the overall size is suppressed with a simple configuration and the amount of hydraulic oil stored is suppressed.

According to the fourth aspect of the present invention, since the storage portion of the cam phase variable mechanism is separate from the cylinder head, the dimensions of the engine and the cylinder head that do not require the cam phase variable mechanism are increased. It can be shared at the location of the part.
According to the engine with a variable valve device of claim 5 of the present invention, the drain oil passage of the control valve for controlling the operation of the cam phase variable mechanism is opened to the space in the cylinder head. It is possible to prevent an increase in the amount of hydraulic oil stored.

According to the engine with a variable valve device of claim 6 of the present invention, the processing of the mounting portion of the part related to the cam phase variable mechanism is accommodated by disposing the detecting means in the accommodating portion separate from the cylinder head cover. The processing cost can be reduced.

It is a top view which shows the structure in the cylinder head in the engine with a variable valve apparatus of this embodiment. It is sectional drawing which shows the structure of an intake camshaft. FIG. 6 is a rear view of the engine showing the attachment state of the actuator cover and the cylinder head cover. It is a perspective view which shows the outer side shape of an actuator cover. It is a perspective view which shows the inner side shape of an actuator cover. It is sectional drawing which shows the shape of the weir of an actuator cover. It is sectional drawing which shows the shape of the groove | channel of an actuator cover.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a top view showing a structure in a cylinder head 2 of an engine with a variable valve operating apparatus (hereinafter simply referred to as an engine 1) of the present embodiment. FIG. 2 is a cross-sectional view showing the structure of the intake camshaft 4.
The engine 1 of this embodiment is an in-line three-cylinder engine having a DOHC valve operating mechanism. As shown in FIG. 1, cam sprockets 5 and 6 are connected to an exhaust camshaft 3 and an intake camshaft 4 (corresponding to the camshaft of the present application), which are rotatably supported inside the cylinder head 2, respectively. These cam sprockets 5 and 6 are connected to a crankshaft (not shown) via a chain 7.

  One cylinder 8 of the engine 1 is provided with two intake valves 9 and 10 and two exhaust valves (not shown). The two intake valves 9, 10 are driven by first intake cams 11 and second intake cams 12 that are alternately arranged on the intake camshaft 4. Specifically, of the two intake valves, the first intake valve 9 is driven by the first intake cam 11, and the second intake valve 10 is driven by the second intake cam 12. The two exhaust valves are driven by an exhaust cam 13 fixed to the exhaust camshaft 3.

  As shown in FIG. 2, the intake camshaft 4 has a double structure including a hollow outer camshaft 21 and an inner camshaft 22 inserted into the outer camshaft 21. The outer cam shaft 21 and the inner cam shaft 22 are arranged concentrically with a slight gap, and are rotatably supported by a plurality of cam journals 23 formed on the cylinder head 2 of the engine 1.

The first intake cam 11 is fixed to the outer cam shaft 21. A second intake cam 12 is supported on the outer cam shaft 21 so as to be rotatable. The second intake cam 12 includes a substantially cylindrical support portion 12 a into which the outer cam shaft 21 is inserted, and a cam peak portion 12 b that protrudes from the outer periphery of the support portion 12 a and drives the second intake valve 10. . The second intake cam 12 and the inner cam shaft 22 are fixed by a fixing pin 24. The fixing pin 24 passes through the support portion 12a of the second intake cam 12, the outer cam shaft 21, and the inner cam shaft 22, and is inserted into a hole provided in the inner cam shaft 22 without a substantial gap and is supported. It is fixed to the part 12a. A long hole 25 through which the fixing pin 24 passes is formed in the outer cam shaft 21 so as to extend in the circumferential direction.
Therefore, the first intake cam 11 is driven by the rotation of the outer cam shaft 21, and the second intake cam 12 is driven by the rotation of the inner shaft 22.

  As shown in FIG. 1, the intake camshaft 4 is provided with a first cam phase variable mechanism 30 and a second cam phase variable mechanism 31. For example, a known vane type hydraulic actuator is used for the first cam phase variable mechanism 30 and the second cam phase variable mechanism 31. The vane hydraulic actuator is configured such that a vane rotor is rotatably provided in a cylindrical housing (cover), and varies the rotation angle of the vane with respect to the housing according to the supply of hydraulic oil into the housing. It has a function. The second cam phase variable mechanism 31 corresponds to the cam phase variable mechanism of the present application.

A first cam phase variable mechanism 30 is provided at the front end of the intake camshaft 4. Specifically, the cam sprocket 6 is fixed to the housing of the first cam phase varying mechanism 30, and the outer cam shaft 21 is fixed to the vane rotor of the first cam phase varying mechanism 30.
A second cam phase variable mechanism 31 is provided at the rear end of the intake camshaft 4. Specifically, the outer cam shaft 21 is fixed to the housing 31 a of the second cam phase variable mechanism 30, and the inner cam shaft 22 is fixed to the vane rotor of the second cam phase variable mechanism 31.

  Therefore, the first cam phase varying mechanism 30 has a function of varying the rotation angle of the outer cam shaft 21 with respect to the cam sprocket 6, while the second cam phase varying mechanism 31 is an inner cam shaft 22 with respect to the outer cam shaft 21. Has a function of varying the rotation angle. That is, the first cam phase varying mechanism 30 has a function of varying the opening / closing timing of the entire first intake valve 11 and the second intake valve 12 with respect to the opening / closing timing of the exhaust valve, and the second cam phase. The variable mechanism 31 has a split variable function that varies the difference between the opening / closing timing of the first intake valve 11 and the opening / closing timing of the second intake valve 12.

A first cam sensor 32 that detects the actual rotation angle of the outer camshaft 21 is attached to the cylinder head 2. The first cam sensor 32 is used for operation control of the first cam phase variable mechanism 30.
The rear end of the intake camshaft 4 passes through the rear wall 2 a of the cylinder head 2, and the second cam phase variable mechanism 31 is disposed outside the cylinder head 2. A cam journal 23 a that supports the rear end portion of the intake camshaft 4 is provided on the rear wall 2 a of the intake camshaft 4.

FIG. 3 is a rear view of the engine 1 showing how the actuator cover 40 and the cylinder head cover 41 are attached. FIG. 4 is a perspective view showing the outer shape of the actuator cover 40, and FIG. 5 is a perspective view showing the inner shape of the actuator cover 40.
As shown in FIGS. 1 and 3 to 5, an actuator cover 40 (housing portion) is fixed to the cylinder head 2 by a bolt 42. The actuator cover 40 is fixed to the cylinder head 2 so as to cover the lower half of the second cam phase varying mechanism 31 whose outer shape is cylindrical, with a slight gap.

  The actuator cover 40 is open at the top, and is formed so that the upper surface 40 a thereof is flush with the upper surface 2 b of the cylinder head 2 when fixed to the cylinder head 2. The cylinder head cover 41 covering the upper surface of the cylinder head 2 has a shape protruding rearward from the cylinder head 2 so as to also cover the upper surface of the actuator cover 40. Thus, a space 43 for accommodating the second cam phase varying mechanism 30 is formed by a part of the actuator cover 40 and the cylinder head cover 41.

The contact surface 40b of the actuator cover 40 with the cylinder head 2 is formed with a seal groove 40c for storing a rubber seal for preventing oil leakage from the internal space 43.
The actuator cover 40 includes an OCV (oil control valve, which corresponds to the control valve of the present application) 44 that controls the intake and discharge of hydraulic oil to and from the second cam phase variable mechanism 31, and a vane rotor of the second cam phase variable mechanism 31. A second cam sensor 45 (detection means) for detecting the rotation timing is attached.

  The hydraulic oil is supplied to the OCV 44 from the hydraulic oil passage formed in the cylinder head 2 through the oil passage 40 g formed in the actuator cover 40. Then, hydraulic fluid is supplied from the OCV 44 to the second cam phase varying mechanism 31 through an oil passage 40d formed in the actuator cover 40, the cylinder head 2, and an oil passage (not shown) formed in the outer shaft 21. The drain of the OCV 44 passes through the drain oil passage 40 h formed in the actuator cover 40 and the drain oil passage 2 c in the rear wall 2 a of the cylinder head 2 and is returned into the cylinder head 2.

The second cam sensor 45 faces the part fixed to the vane rotor of the outer peripheral wall 31b of the second cam phase varying mechanism 31 and is fixed to the actuator cover 40, and detects the actual rotation angle of this part. Thus, the actual rotation angle of the inner camshaft 22 is detected.
Therefore, the second cam sensor 45 can detect the actual rotation angle difference between the outer cam shaft 21 and the inner cam shaft 22, and this actual rotation angle difference is used to control the operation of the second cam phase variable mechanism 31. That is, it is used to control the OCV 44.

FIG. 6 is an explanatory diagram showing the position of the oil passage 50 of the cylinder head 2 and the position of the weir 52 provided in the actuator cover 40.
An oil passage 50 is formed in the rear wall 2a of the cylinder head 2 to communicate the space 43 in the actuator cover 40 and the space 51 in the cylinder head. As shown in FIG. 6, the oil passage 50 faces the gap between the inner peripheral wall 40 e of the actuator cover 40 and the outer peripheral wall 31 b of the second cam phase varying mechanism 31, and the second cam phase from the bottom. The variable mechanism 31 is disposed on the rotational direction side.

  As shown in FIGS. 5 and 6, the inner peripheral wall 40 e of the actuator cover 40 is provided with a weir 52 (introducing means) protruding upward. The height of the weir 52 is set so as not to contact the outer peripheral wall 31 b of the rotating second cam phase varying mechanism 31. The weir 52 is provided so as to be inclined upward from the rear wall 40 f side toward the cylinder head 2, and the end 52 a on the cylinder head 2 side is set to be located above the oil return hole 50. .

  As described above, in the present embodiment, the second cam phase varying mechanism 31 that varies the phase difference between the two intake valves 9 and 10 is housed in the space 43 in the actuator cover 40. A space 43 in the actuator cover 40 is another space that separates the space 51 in the cylinder head 2 from the rear wall 2a. The second cam phase variable mechanism 31, which is a hydraulic actuator, may leak hydraulic oil due to its structure, but even if hydraulic oil leaks from the second cam phase variable mechanism 31, the actuator cover 40 may The outflow to the is prevented. Further, since the space for housing the second cam phase varying mechanism 31 and the space 51 in the cylinder head 2 are different spaces, the lubricant oil splashed in the space 51 in the cylinder head 2 is not covered by the actuator cover. Inflow into the space 43 in the 40 can be prevented.

  In particular, in this embodiment, since the space 43 in the actuator cover 40 and the space 51 in the cylinder head 2 are communicated by the oil passage 50, even if hydraulic fluid leaks from the second cam phase variable mechanism 31. It is possible to prevent the hydraulic oil from being discharged from the space 43 in the actuator cover 40 to the space 51 in the cylinder head 2 through the oil passage 50 and stored in the actuator cover 40.

Further, since the drain of the OCV 44 is not opened to the space 43 in the actuator cover 40 but to the space 51 in the cylinder head 2, it is possible to prevent the hydraulic oil from being stored in the actuator cover 40 by the drain of the OCV 44. it can.
In this way, by suppressing the storage of the hydraulic oil in the actuator cover 40, the friction due to the agitation of the hydraulic oil can be reduced when the second cam phase variable mechanism 31 rotates along with the rotation of the intake camshaft 4. In addition, the operation responsiveness of the second cam phase variable mechanism 31, that is, the variable responsiveness of the second intake valve 10 can be improved.

  Further, since the inner peripheral wall 40e of the actuator cover 40 is formed in an arc shape along the outer peripheral wall 31b of the second cam phase varying mechanism 31, the hydraulic oil is not sufficiently discharged from the actuator cover 40, for example. Even if the oil is stored, the hydraulic oil is smoothly agitated when the second cam phase variable mechanism 31 rotates, and an increase in friction can be suppressed. Further, since aeration can be suppressed by smooth agitation of the hydraulic oil, when the hydraulic oil in the actuator cover 40 is recovered and reused as hydraulic oil for the second cam phase variable mechanism 31 and the like. As a result, a decrease in operating hydraulic pressure due to aeration can be suppressed, and a decrease in operating responsiveness of the second cam phase variable mechanism 31 and the like can be prevented.

Further, since there is a slight gap between the inner peripheral wall 40e of the actuator cover 40 and the outer peripheral wall 31b of the second cam phase variable mechanism 31, the amount of hydraulic oil in the actuator cover 40 can be suppressed, and the hydraulic oil Stirring resistance can be suppressed.
Furthermore, a weir 52 is provided on the inner peripheral wall 40 e of the actuator cover 40, and the hydraulic oil in the actuator cover 40 that is agitated by the rotation of the second cam phase varying mechanism 31 by the weir 52 is an oil passage 50. Therefore, the hydraulic oil in the actuator cover 40 can be smoothly discharged from the oil passage 50. Accordingly, it is possible to quickly eliminate hydraulic oil storage and to quickly reduce hydraulic oil agitation resistance.

  The actuator cover 40 has a structure in which the lower half of the second cam phase varying mechanism 31 is housed and the upper half of the second cam phase varying mechanism 31 is covered by the cylinder head cover 41. Thus, since the actuator cover 40 and the cylinder head cover 41 cover the entire circumference of the second cam phase variable mechanism 31 with a relatively small gap, the overall dimensions are reduced with a simple configuration, and the hydraulic oil is contained inside. The second cam phase variable mechanism 31 can be stored while suppressing the storage of the first cam phase.

  Further, since the actuator cover 40 is a separate component from the cylinder head 2, the cylinder head 2 can be shared in most places with a conventional engine without the second cam phase variable mechanism 31. It becomes. Thereby, the processing cost of the cylinder head 2 can be reduced. In particular, by sharing the entire length of the cylinder head 2 with that of a conventional engine cylinder head, it is possible to share most of the processing line during production.

Furthermore, since the devices necessary for the operation of the second cam phase variable mechanism 31 such as the OCV 44 and the second cam sensor 45 are arranged on the actuator cover 40, the mounting process of these devices is concentrated on the actuator cover 40. The processing cost can be reduced as compared with the case of providing the cylinder head 2 having a relatively large size.
Further, as shown in FIG. 6, when the magnet is built in the detection surface 45a, the second cam sensor 45 has a detection surface 45a that is contaminated with iron powder due to wear or the like inside the engine. It may adhere and lead to erroneous detection of the second cam sensor 45. However, since the entire circumference of the second cam phase varying mechanism 31 is covered with a relatively small gap, the amount of hydraulic oil applied to the detection surface 45a is small, and adhesion of iron powder is prevented. Furthermore, it is arranged so as to be positioned above the weir 52 and in the rotational direction of the second cam phase varying mechanism 31, and even when iron powder is mixed into the hydraulic oil in the space 43, the weir As a result, the hydraulic oil does not reach the detection surface 45 by 52, and iron powder hardly accumulates in front of the detection surface 45, so that erroneous detection of the second cam sensor 45 can be prevented.

FIG. 7 is a structural diagram showing the shape of a groove 53 which is another embodiment of the introducing means.
In the above embodiment, the weir 52 is provided in the actuator cover 40 as an introduction means for introducing the hydraulic oil into the oil passage 50. However, a groove 53 may be provided instead of the weir 52 as shown in FIG. . Like the weir 52, the groove 53 is inclined upward from the rear wall 40f side to the cylinder head 2 side, and the end 53a on the cylinder head 2 side faces the oil passage 50. Is set.

Accordingly, like the weir 52, the hydraulic oil in the actuator cover 40 that is agitated by the rotation of the second cam phase varying mechanism 31 is easily guided to the oil passage 50, and the hydraulic oil in the actuator cover 40 is supplied to the oil passage 50. Can be discharged smoothly.
In the present embodiment, the actuator cover 40 that houses the second cam phase variable mechanism 31 is separate from the cylinder head 2, but the space 51 in the cylinder head 2 and the second cam phase variable mechanism 31. A structure integrated with the cylinder head 2 may be used as long as the space 43 for storing the air is partitioned. In addition, the cylinder head cover 41 is configured to cover the upper half of the second cam phase varying mechanism 31, but a member that covers the upper half of the second cam phase varying mechanism 31 may be provided separately from the cylinder head cover 41. Good.

  In the above-described embodiment, in addition to the second cam phase variable mechanism 31 that performs so-called split variable, which varies the phase difference between the first intake valve 9 and the second intake valve 10, the first intake valve Although the first cam phase variable mechanism 30 that varies the phase of the entire second intake valve is provided, the present invention can be applied to an engine that includes only the second cam phase variable mechanism 31. In this case, the cam sprocket 6 may be fixed to the tip of the outer cam shaft 21.

  Furthermore, in the above-described embodiment, the present invention is applied to an in-line three-cylinder engine having a DOHC type valve operating mechanism.

DESCRIPTION OF SYMBOLS 1 Engine 2 Cylinder head 2c Drain oil path 4 Intake camshaft 31 2nd cam phase variable mechanism 40 Actuator cover 40h Drain oil path 41 Cylinder head cover 44 OCV
45 Second cam sensor 50 Oil passage 52 Weir 53 Groove

Claims (6)

An engine with a variable valve operating system, provided at one end of the camshaft, comprising a hydraulically driven cam phase variable mechanism that varies the phase of a valve drive cam, and a storage portion that houses the cam phase variable mechanism. Because
Inside the storage portion, a space is formed that separates a partition wall from a space for storing the valve in the cylinder head, and the cam phase variable mechanism is stored in the space,
The partition is formed with an oil passage communicating the space in the storage portion and the space in the cylinder head ,
An engine with a variable valve operating device , characterized in that an introduction means is provided on the inner wall of the storage portion to guide hydraulic oil in the storage portion to the oil passage by rotation of the cam phase variable mechanism . The cam phase variable mechanism has a cylindrical outer shape and is arranged coaxially with the camshaft,
2. The engine with a variable valve mechanism according to claim 1, wherein an inner wall of the storage portion is formed in an arc shape along an outer periphery of the cam phase variable mechanism. The storage portion is open at the top and the internal space is formed in a semi-cylindrical shape, covering the lower half of the cam phase variable mechanism,
3. The engine with a variable valve operating system according to claim 1, wherein an upper portion of the storage portion is covered with a cylinder head cover having an inner wall formed in an arc shape along an outer periphery of the cam phase variable mechanism. The engine with a variable valve operating system according to any one of claims 1 to 3 , wherein the storage portion is formed separately from the cylinder head and is fixed to the cylinder head. A control valve for controlling the operation of the cam phase variable mechanism is fixed to the storage portion,
The engine with a variable valve gear according to any one of claims 1 to 4 , wherein a drain oil passage of the control valve is opened to a space in the cylinder head. 5. The variable valve geared engine according to claim 4 , wherein a detecting means for detecting a cam phase variably controlled by the cam phase varying mechanism is provided in the housing portion.

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