JP7184467B2 - Arrangement structure of filters - Google Patents

Description

The present invention relates to a structure for arranging a filter for filtering lubricating oil of an internal combustion engine.

Regarding internal combustion engines (reciprocating engines) mounted on vehicles, those equipped with a phase change type variable valve timing mechanism capable of variably controlling the opening/closing timing of intake valves and/or exhaust valves are known (e.g. , See Patent Document 1 below). This type of VVT mechanism changes the rotational phase of an intake camshaft that drives the intake valves to open and close and/or an exhaust camshaft that drives the exhaust valves to open and close with respect to the crankshaft, which is the output shaft of the internal combustion engine. and/or advance or retard the opening/closing timing of the exhaust valve.

In a widely used vane type VVT mechanism, lubricating oil (engine oil) of an internal combustion engine is used as a working fluid, and the rotational phase of the camshaft with respect to the crankshaft is shifted by the lubricating oil pressure. On the hydraulic circuit, an OCV (Oil Control Valve), which is an electromagnetic switching control valve, is installed, and by controlling the flow rate and direction of the lubricating oil via the OCV, the camshaft can be adjusted relative to the crankshaft. Rotate.

The rotational phase of the camshaft, in other words, the valve timing realized by the VVT mechanism is feedback controlled. That is, based on the deviation between the current rotational phase and the target phase, the DUTY ratio of the control signal input to the OCV, which is a control valve, is increased or decreased to operate the OCV in the direction of reducing the deviation. When the rotational phase of the camshaft reaches the vicinity of the target phase, that is, when the valve timing reaches the target timing, the OCV is set to the neutral position to cut off the flow of lubricating oil and prohibit the displacement of the rotational phase of the camshaft. to maintain the valve timing at the target timing.

Lubricating oil for the internal combustion engine is stored in an oil pan in the crankcase, and is sucked and discharged by a lubricating oil pump (oil pump) and pumped to various parts of the internal combustion engine. Most lubricating oil pumps are mechanical pumps that follow a crankshaft of an internal combustion engine and operate by receiving engine torque from the crankshaft. A filter is arranged between the lubricating oil pump and the OCV for filtering the lubricating oil flowing into the OCV and the VVT mechanism to remove foreign matter (deposits). A filter is made by drilling a retaining hole in the cylinder head of an internal combustion engine or a component thereof (which may be a cam cap or the like), inserting the filter into the retaining hole, and then screwing a bolt into the retaining hole to hold it in place. It is installed in a closed form (for example, see Patent Document 2 below).

JP 2018-172967 A Japanese Patent Application Laid-Open No. 2000-073716

Since the mesh of the filter that filters the lubricating oil gradually becomes clogged, it is necessary to replace the filter from time to time.

In a conventional internal combustion engine, the holding hole in which the filter attached to the OCV is arranged is in a direction non-parallel to the extension direction of the camshaft (also the direction in which the cylinders are arranged) in the cylinder head or its constituent members. was open to A front-exhaust internal combustion engine (intake ports, intake valves, and intake camshafts of the cylinders are located on the rear side of the vehicle, and exhaust ports, exhaust valves, and camshafts of the cylinders are located on the front side of the vehicle) internal combustion engine mounted on the vehicle body. When the engine is installed horizontally (the crankshaft and camshaft extend in the lateral direction of the vehicle), it takes time and effort to replace the filter associated with the OCV of the intake VVT mechanism. This is because a worker who wants to replace the filter must open the hood of the vehicle body and stick his or her hand behind the internal combustion engine in the engine room (engine compartment).

SUMMARY OF THE INVENTION The main object of the present invention is to reduce the time and effort required for filter replacement work associated with an OCV.

The arrangement structure of the filter according to the present invention includes a holding hole formed in a camshaft that opens and closes an intake valve or an exhaust valve of a cylinder of an internal combustion engine and opens at the shaft end of the camshaft, and an axial center of the holding hole. a supply oil passage through which lubricating oil flows into the holding hole from the outer side to the inner side intersecting the direction; A bolt is inserted into the holding hole from the axial end side of the camshaft and is screwed closer to the axial end side than the filter to close the holding hole.

Advantageous Effects of Invention According to the present invention, it is possible to reduce the trouble of replacing a filter associated with an OCV.

1 is a hydraulic circuit diagram showing a VVT mechanism attached to an internal combustion engine according to one embodiment of the present invention; FIG. FIG. 2 is a plan sectional view showing the arrangement structure of a filter in the internal combustion engine of the same embodiment;

One embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows the configuration of a crankshaft, a camshaft 2, and a VVT mechanism associated therewith of a vehicle internal combustion engine, which is a four-stroke engine. In this type of internal combustion engine, a timing chain (or belt) 74 is wound around a crank sprocket (or pulley) 71, an intake side sprocket (or pulley) 72, and an exhaust side sprocket (or pulley) 73. The chain 74 transmits rotational driving force from the crankshaft to the intake camshaft 2 via the intake side sprocket 72 and to the exhaust camshaft via the exhaust side sprocket 73 .

The intake VVT mechanism 6, which changes the opening/closing timing of the intake valves of each cylinder of the internal combustion engine, is interposed between the intake side sprocket 72 and the intake camshaft 2, and displaces the rotation phase of the intake camshaft 2 with respect to the crankshaft. is.

A housing 61 of the VVT mechanism 6 is fixed to the intake side sprocket 72, and the intake side sprocket 72 and the housing 61 rotate together in synchronization with the crankshaft. On the other hand, the rotor 62 fixed to one end of the intake camshaft 2 is accommodated in the housing 61 and can rotate relative to the intake side sprocket 72 and the housing 61 . A plurality of fluid chambers into which hydraulic fluid flows are formed inside the housing 61 , and each fluid chamber is divided into an advance chamber 612 and a retard chamber 611 by vanes 621 formed on the outer periphery of the rotor 62 . It is

A hydraulic (hydraulic) circuit of the VVT mechanism 6 is supplied with lubricating oil of the internal combustion engine, which is hydraulic fluid stored in an oil pan 81, from a lubricating oil pump 82, which is a hydraulic fluid pump. The lubricating oil pump 82 is a mechanical hydraulic pump that operates by receiving rotational torque transmitted from the crankshaft of the internal combustion engine. An OCV 9 as a control valve is provided between the lubricating oil pump 82 and the VVT mechanism 6 . By manipulating the flow rate and direction of the hydraulic fluid through the OCV 9 , the hydraulic fluid pumped from the oil pan 81 can be selectively supplied to the advance chamber 612 or the retard chamber 611 . Then, the housing 61 rotates relative to the rotor 62, and the opening/closing timing of the intake valve can be advanced or retarded.

The OCV 9 shown in FIG. 1 is a so-called electromagnetic four-way spool valve, and includes a supply port 91 connected to the discharge port of the lubricating oil pump 82, an A port 92 connected to the advance angle chamber 612 of the housing 61, and the housing 61 has a B port 93 connected to the retarded angle chamber 611 and drain ports 94, 95 connected to the oil pan 81. The spool of the OCV 9 switches the internal fluid path by moving back and forth along the axial direction to connect the A port 92 and B port 93 to either the supply port 91 or the drain ports 94 and 95, respectively. Also, when the spool 96 is in its neutral position, the internal fluid path is interrupted, preventing the A port 92 and B port 93 from communicating with either the supply port 91 or the drain ports 94,95. FIG. 1 shows the spool 96 in a neutral position.

Spool 96 is driven by solenoid 97 . That is, the forward/backward distance of the spool 96 changes according to the DUTY ratio of the pulse current (or voltage) signal m input to the solenoid 97 as a control input. For example, when the DUTY ratio of the control signal m is 0% and the whole is OFF, the spool 96 is located at the most one end side (left side in FIG. 1), and the B port 93 is closed with the channel cross-sectional area being the maximum. An internal fluid path is laid to communicate with the supply port 91 and to communicate the A port 92 with the drain port 94 .

As the DUTY ratio of the control signal m increases, the spool 96 attracted by the solenoid 97 moves toward the other end side (rightward in FIG. 1). Until the DUTY ratio increases to around 50%, the internal fluid path of the OCV 9 does not switch, and the flow path cross-sectional area decreases as the DUTY ratio increases.

When the duty is about 50% holding duty ratio, the spool 96 assumes a neutral position, completely blocking the internal fluid path of the OCV 9 .

Further increasing the DUTY ratio of control signal m switches the internal fluid path of OCV 9 . That is, the spool 96 is displaced from the neutral position to the other end side, and the internal fluid path is laid so that the A port 92 communicates with the supply port 91 and the B port 93 communicates with the drain port 95 . As the DUTY ratio increases, the cross-sectional area of the flow passage also increases. is the maximum state.

When the duty ratio of the control signal m is relatively large, the working fluid pressure discharged from the lubricating oil pump 82 is supplied to the advance chamber 612 through the A port 92, while it is already stored in the retard chamber 611. Hydraulic fluid flows down toward the oil pan 81 through the B port 93, and the vanes 621 and the rotor 62 rotate so that the volume of the advance chamber 612 increases and the volume of the retard chamber 611 decreases. As a result, the rotation phase of the intake camshaft 2, in other words, the displacement angle of the intake camshaft 2 with respect to the crankshaft advances, and the opening/closing timing of the intake valve advances.

Conversely, when the duty ratio of the control signal m is relatively small, the hydraulic pressure discharged from the lubricating oil pump 82 is supplied to the retard chamber 611 through the B port 93, while it is already stored in the advance chamber 612. Hydraulic fluid flowing down through the A port 92 toward the oil pan 81 causes the vanes 621 and the rotor 62 to rotate so that the volume of the retard chamber 611 increases and the volume of the advance chamber 612 decreases. . As a result, the displacement angle of the intake camshaft 2 with respect to the crankshaft is retarded, and the opening/closing timing of the intake valves is retarded.

Generally speaking, the more the duty ratio of the control signal m is greater than neutral, the faster the intake valve timing advances, and the less the duty ratio is neutral, the faster the intake valve timing retards.

A filter 1 is arranged between the lubricating oil pump 82 and the OCV 9 to filter the lubricating oil flowing into the OCV 9 and the VVT mechanism 6 to remove foreign matter.

FIG. 2 shows the arrangement structure of the filter 1 in the internal combustion engine of this embodiment. FIG. 2 is a cross-sectional plan view cut along a plane passing through the central axis of the intake camshaft 2. The lower part of the drawing is the front of the vehicle on which the internal combustion engine is mounted horizontally, and the left part of the drawing is the left side of the vehicle (driving). The right side of the drawing is the right side of the vehicle (left hand side for the driver).

In the present embodiment, a holding hole 3 is formed in the intake camshaft 2 and in the VVT mechanism 6 near the central axis thereof, the holding hole 3 opening at the axial end of the intake camshaft 2 and penetrating the VVT mechanism 6 to open outward. is provided. The axial direction of the holding hole 3 is parallel or substantially parallel to the extending direction of the intake camshaft 2 .

At the same time, a supply oil passage 83 is formed in the intake camshaft 2 intersecting (or perpendicular to) the axial direction of the holding hole 3 and allowing the lubricating oil to flow inward from the outer side. . The supply oil passage 83 extends along the radial direction of the holding hole 3 and communicates with the holding hole 3 . Lubricating oil discharged and pressure-fed by the lubricating oil pump 82 flows into the holding hole 3 via the supply oil passage 83 . However, part of the lubricating oil discharged by the lubricating oil pump 82 branches upstream of the supply oil passage 83 and is supplied to a cam shower or the like that lubricates the intake camshaft 2 , and does not flow into the supply oil passage 83 .

After that, the filter 1 is inserted and disposed deep inside the holding hole 3 . The filter 1 is formed by molding a porous material such as a fine metal net (mesh) into a cylindrical shape. As indicated by arrows in FIG. 2 , lubricating oil flowing through the supply oil passage 83 passes through the porous outer peripheral wall of the filter 1 and flows into the holding hole 3 . At that time, foreign matter mixed in the lubricating oil is filtered out by the filter 1 .

Furthermore, the opening of the holding hole 3 is closed by inserting and screwing the center bolt 9 into the holding hole 3 from the outside, that is, from the shaft end side of the camshaft 2 . In this embodiment, the OCV 9 also serves as the center bolt. That is, in this embodiment, a male thread 98 is formed on the outer periphery of the tip portion of the housing 90 of the OCV 9, while a female thread 31 is formed on the inner periphery of the holding hole 3 in front of the supply oil passage 83 and the filter 1. Then, the housing 90 of the OCV 9 is secured to the holding hole 3 by screwing the male thread 98 onto the female thread 31 and tightening. In this embodiment, the filter 1 and the OCV 9 are arranged along the axial direction.

The lubricating oil that has flowed into the holding hole 3 from the supply oil passage 83 through the filter 1 reaches the supply port 91 of the OCV 9 through an oil passage (not shown) formed by cutting the inner circumference of the holding hole 3. into the housing 90 of the OCV 9 through. Then, as indicated by arrows in FIG. 2 , it goes through the A port 92 to the advance chamber 612 of the VVT mechanism 6 or through the B port 93 to the retard chamber 611 of the VVT mechanism 6 .

When the intake camshaft 2 rotates following the crankshaft of the internal combustion engine, the filter 1 accommodated in the holding hole 3 therein also rotates. Therefore, a centrifugal force in a direction away from the axial center of the filter 1 acts on the foreign matter adhering to the outer peripheral surface of the filter 1 . The centrifugal force promotes detachment of the foreign matter from the filter 1 radially outward. This helps prevent clogging of the filter 1 when starting the internal combustion engine.

In this embodiment, a holding hole 3 is formed in a camshaft 2 that opens and closes an intake valve of a cylinder of an internal combustion engine and opens at the axial end of the camshaft 2. A supply oil passage 83 that allows lubricating oil to flow into the holding hole 3 from the outside to the inside of the crossing, and filters the lubricating oil that is accommodated in the holding hole 3 and flows into the holding hole 3 from the supply oil passage 83. and an OCV 9, which is a bolt that is inserted into the holding hole 3 from the shaft end side of the camshaft 2 and screwed to close the holding hole 3, is provided.

According to this embodiment, it is possible to reduce the trouble of replacing the filter 1 attached to the OCV 9 . In particular, when the internal combustion engine is laterally mounted on the vehicle body, the shaft end of the camshaft 2 and the VVT mechanism 6 are exposed to the side of the vehicle. For this reason, an operator who wants to replace the filter 1 removes the bolt, that is, the OCV 9 from the holding hole 3, removes the old filter 1 from the holding hole 3, inserts the new filter 1 into the holding hole 3, and then re-inserts the OCV 9. is easily screwed into the holding hole 3.

In addition, since the filter 1 is arranged by making effective use of the area inside the camshaft 2 and the OCV 9 is used as a center bolt, it contributes to the compactness of the structure of the internal combustion engine and the reduction in the number of parts. can. It also eliminates the need for special processing of the cylinder head or its constituent members.

The present invention is not limited to the embodiments detailed above. In the above embodiment, the arrangement structure of the filter 1 attached to the OCV 9 of the intake VVT mechanism 6 was assumed. The arrangement structure of the filter associated with the OCV of the exhaust VVT mechanism can be built into the shaft end of the exhaust camshaft in the same manner as in the above embodiment.

In addition, the specific configuration of each part can be modified in various ways without departing from the scope of the present invention.

INDUSTRIAL APPLICABILITY The present invention can be used to control an internal combustion engine mounted on a vehicle.

DESCRIPTION OF SYMBOLS 1... Filter 2... Intake camshaft 3... Holding hole 6... Intake VVT mechanism 83... Supply oil passage 9... Bolt, OCV

Claims (1)

a holding hole that is formed in a camshaft that opens and closes an intake valve or an exhaust valve of a cylinder of an internal combustion engine and opens at an axial end of the camshaft;
a supply oil passage that intersects with the axial direction of the holding hole and allows lubricating oil to flow into the holding hole from the outer side toward the inner side;
a filter that is housed in the holding hole and filters the lubricating oil flowing into the holding hole from the supply oil passage;
A filter arrangement structure comprising a bolt that is inserted into the holding hole from the axial end side of the camshaft and screwed closer to the axial end side than the filter to close the holding hole.

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