JP2019178622A - Internal combustion engine - Google Patents

Abstract

To reduce a cost by decreasing the number of cutting processes of a cylinder head, and to prevent the clogging of an oil passage caused by chips, in an internal combustion engine having a VVT device which is controlled by a hydraulic OCV.SOLUTION: An OCV 13 is attached to a front end part in a longitudinal direction of a cylinder head 1. Control oil passages 18, 19 for supplying oil to a VVT device from the OCV 13 are formed as drill holes which are linearly formed toward the cylinder head 1, and other ends 18b, 19b of the control oil passages 18, 19 are opened at an internal peripheral face of a front bearing part 5. The control oil passages 18, 19 can be linearly formed merely by drill processing, so that when finish-processing a bearing hole in a state that a front cam cap is fixed, even if chips intrudes into the bearing hole, the chips can be easily and surely removed by the injection or the like of compressed air.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an internal combustion engine equipped with a hydraulic VVT device (variable valve timing device).

  In internal combustion engines for vehicles and the like, the opening / closing timing (valve timing) of one or both of an intake valve and an exhaust valve is controlled. As a control device for this valve timing, the camshaft is controlled to advance or retard with respect to the chain sprocket. A hydraulic VVT device controlled by the above is used.

  The hydraulic type VVT device is controlled by an oil control valve (OCV). By supplying oil pressure-fed by an oil pump to the OCV, the destination of the oil is switched and the feed amount is adjusted by the OCV. Controls the advance / retard angle of the cam.

  In the relationship between the camshaft and the VVT device, an oil passage is provided in the camshaft and oil is supplied while allowing the rotation of the VVT device. However, since the OCV is disposed in the cylinder head, the OCV and the camshaft are arranged. It is necessary to form an oil passage between the two.

  In this regard, in Patent Document 1, in a configuration in which a horizontal hole is formed in the front portion of the longitudinal side surface of the cylinder head and the OCV is fitted in the horizontal hole, an oil passage extending from the OCV to the camshaft is formed on the upper surface of the cylinder head. It is disclosed that the groove portion is formed and a drill hole communicated with the groove portion.

Japanese Patent No. 3498821

  The groove that becomes the control oil passage is also formed on the lower surface of the front top. However, the groove is formed in the cylinder head or in the front top in plan view (or bottom view). Often has a bent shape.

  On the other hand, the opposed surfaces of the front bearing and the cam cap are semicircular and constitute a perfect circle as a whole, but in order to ensure the roundness, the recesses of both are made larger than the original dimensions. After the diameter is set to a small value, a bearing hole formed by both of the front cam caps is fixed to the cylinder head and is finished by cutting with a drill or a mill to a predetermined size.

  In this cutting process, chips are generated, but the generated chips enter the groove portion for the control oil passage, and there is a phenomenon that the bent portion is particularly clogged.

  In other words, the cylinder head and the front cam cap are made of aluminum, and the chips are likely to be in the form of a thin band (chip shape), so that they are pushed into the groove portion in an elastically deformed state, especially at the bent portion There is a case where it is stretched into the groove portion by force, and therefore, the chips may not be eliminated by the extent that the compressed air is injected.

  In this case, it is manually removed using a tool, but not only does the cost of removal work increase, but it remains unremoved and enters the OCV or VVT apparatus. It may cause malfunction. In general, since the groove portion is formed by casting, the inner surface of the groove portion is often a cast surface composed of fine irregularities, and thus clogging of chips is likely to occur.

  The present invention has been made in view of such a current situation, and an object thereof is to form a control oil passage that can prevent clogging of chips due to cutting.

The internal combustion engine of the present invention is
“The camshaft, which is rotatable relative to the chain sprocket by the hydraulic VVT device, is rotatably held by a plurality of bearings of the cylinder head via cam caps, and an oil control valve (OCV) for controlling the VVT device. ) Is attached to the outside of the front bearing portion that rotatably supports the camshaft at the front portion of the cylinder head close to the chain sprocket.
This is the basic configuration.

And, the invention of claim 1 is the above basic configuration,
“A control oil passage for controlling the VVT device is provided at the front of the cylinder head so that one end communicates with the oil control valve and the other end opens on the inner peripheral surface of the front bearing portion. Forming "
It is the composition.

The present invention has various configurations. For example, in claim 2, in claim 1,
“The control oil passage is composed of two oil passages of an advance control oil passage and a retard control oil passage, and these two control oil passages are composed of the camshaft. It is formed as a straight hole apart in the axial direction of
It is the composition.

Further, in claim 3, in claim 1 or 2,
“The front bearing portion protrudes forward from the front wall portion of the cylinder head, and is used for an oil passage for forming the control oil passage on the front surface of the cylinder head and below the front bearing portion. The boss is protruding forward. ''
It is the composition.

As a development example of the invention of claim 3, in claim 4,
“The oil passage for control and the boss portion for oil passage are inclined so as to be lowered from the front bearing portion toward the oil control valve. Counter ribs that are symmetrical with the oil passage ribs are formed. ''
It is the composition.

  In the present invention, the control oil passage from the OCV to the camshaft is a hole directed from the inner peripheral surface of the front bearing portion to the OCV, but can be formed in a straight line. When finishing the inner peripheral surfaces of the intake front bearing and the front cam cap with the front cam cap fixed, even if chips enter the control oil passage, Can be completely removed.

  In particular, if the control oil passage is formed by drilling, the inner surface of the control oil passage becomes much smoother than the cast skin, so even if chip-like chips enter, there is no need to use a tool. It can be easily extruded by jetting compressed air.

  Therefore, according to the present invention, it is possible to reduce the labor of processing and contribute to cost reduction, and to prevent clogging of chips, and to accurately operate the VVT device and the VVT device.

  In general, VVT apparatuses often perform advance angle control and retard angle control. Therefore, the control oil passage is often provided with two oil passages of an advance oil passage and a retard oil passage. In claim 2, the two control oil passages are straight. When drilling, it is possible to contribute to cost reduction because it is sufficient to process each time. In addition, since the length of the oil passage is the shortest, pressure loss can be suppressed and the OCV response can be improved. Further, since the two oil passages are displaced in the axial direction of the cam shaft, it is possible to reliably communicate with the annular groove formed in the cam shaft (thus, the supply of oil to the VVT device can be ensured). ).

  When the VVT device is provided, the front portion of the front bearing portion may protrude forward from the front wall portion of the cylinder head. However, in claim 3, the oil passage boss portion may be provided even if the front bearing portion protrudes forward. By providing the oil path, the oil passage can be formed in the front part as much as possible. Therefore, it is easy to meet the dimensions with the VVT device and the OCV, and the design freedom is high.

  In addition, the cylinder head is generally an aluminum casting, but in claim 3, the oil passage boss protrudes forward, which increases the space for the molten metal to flow during casting. Can contribute to the improvement of casting quality. Further, since the boss part is in a rib state and protrudes from the front surface of the cylinder head, there is an advantage that the rigidity of the cylinder head can be improved by a reinforcing effect.

  If the structure of Claim 3 is employ | adopted, since the control oil path inclines so that it may become low toward OCV from a front bearing part, even if an oil port exists in the outer periphery of OCV, a communication can be ensured. Therefore, the reality correspondence is excellent.

  Further, as described above, the oil passage boss portion has a reinforcing effect. However, when the configuration of claim 4 is adopted, the auxiliary boss portion is formed symmetrically with the oil passage boss portion, and therefore the front bearing portion is enclosed. The rigidity of the part can be made uniform to prevent the occurrence of distortion when an external force or thermal stress is applied to the cylinder head. Therefore, the roundness of the front bearing portion can be maintained at a high level, and smooth rotation of the camshaft can be ensured. Thereby, mechanical loss can be suppressed.

It is the perspective view seen from the front lower part of the cylinder head concerning an embodiment. It is the perspective view seen from the front upper direction. (A) is the perspective view which looked at the principal part from back upper direction, (B) is the perspective view which looked at the principal part from the horizontal downward direction. It is a front view (front view) of a cylinder head. FIG. 5 is a plan view showing a part thereof as a VV sectional view of FIG. 4. (A) is a VIA-VIA sectional view of Drawing 5, (B) is a bottom view of a cam cap. It is the perspective view cut | disconnected by the plane containing the centerline of an OCV attachment hole. (A) is a sectional view taken along the line VIIIA-VIIIA in FIG. 6 (A), and (B) is a sectional view taken along the line VIIIB-VIIIB in FIG. 6 (A). FIG. 6A is a cross-sectional view taken along the line IXA-IXA in FIG. 3B, and FIG. 6B is a cross-sectional view taken along the line IXB-IXB in FIG. It is a partial front view (front view) of an internal combustion engine.

(1). Outline Next, an embodiment of the present invention will be described with reference to the drawings. In the following embodiments, front / rear / left / right words are used to specify the direction, but the front / rear direction is the crank axis direction, and the portion where the front cover (or the chain sprocket 30 and the timing chain 31 in FIG. 10) is disposed is used. As before. As a precaution, the directions are clearly shown in FIGS.

  The basic structure of the cylinder head 1 is the same as the conventional one. For example, as shown in FIG. 2, the cylinder head 1 has a front wall portion 2 and an intake side wall portion 3, an exhaust side wall portion 4 and a rear wall portion (not connected). In general, it is in the form of a box that opens upward. The front wall portion 2 is formed with an intake front bearing portion 5 and an exhaust front bearing portion 6. Reference numeral 4a shown in FIG. 2 is an exhaust outlet.

  The front bearing portions 5 and 6 protrude forward from the front wall portion 2, but the degree of protrusion is larger in the intake front bearing portion 5. On the front surface of the front wall portion 2, bosses, ribs, member mounting holes, and the like are formed.

  Inside the cylinder head 1, a plurality of pairs of intake intermediate bearing portions 7 and exhaust intermediate bearing portions 8 extending in the left-right direction are formed apart from each other in the cam shaft direction. A plug boss portion 9 into which the ignition device is fitted is formed between the intake intermediate bearing portion 7 and the exhaust intermediate bearing portion 8.

  As shown in FIG. 3B, a plurality of intake ports 10 are formed on the intake side surface of the cylinder head 1 so as to be arranged in the front-rear direction. In this embodiment, the intake camshaft 11 is provided with a VVT device (not shown), and therefore, as shown in FIG. 3B and FIG. In addition, an OCV mounting hole 12 is formed in the upper portion, and a hydraulic OCV (oil control valve) 13 is fitted into the OCV mounting hole 12 as shown in FIG.

  As shown in FIG. 10, a chain sprocket 30 is attached to the intake and exhaust camshafts via the rotor of the VVT device, and a timing chain 31 is wound around both the chain sprockets 30. The timing chain 31 is held in a narrowed state by the intake side chain guide 32 and the exhaust side chain guide 33 so that the distance between the forward path and the return path is narrowed.

  While the exhaust side chain guide 33 is fixed, the intake side chain guide 32 is movable so that the tension of the timing chain 31 can be adjusted. A hydraulic auto tensioner 34 as an example of the adjustment tool is provided on the front surface of the cylinder head 1. It is fixed.

(2). OCV Control Structure As shown in FIG. 6, the intake camshaft 11 includes an advance angle longitudinal passage 15, an advance angle annular groove 16 a communicating therewith, and a delay angle length passage. 17 and a retarding annular groove 16b (see FIG. 5) communicating therewith, an advance angle controlling oil passage 18 connecting the OCV 13 and the advance angle annular groove 16a, and the OCV 13 and the retard angle ring One end (upstream end) of the retard control oil passage 19 connecting the grooves 16b communicates with the OCV mounting hole 12, and the other end (downstream end) opens to the inner peripheral surface of the intake front bearing portion 5. It is formed as follows.

  As can be understood from FIGS. 4, 5, and 9 (B), the advance angle control oil passage 18 and the retard angle control oil passage 19 are front and rear with the advance angle control oil passage 18 positioned in front. Are lined up. Further, the advance angle control oil passage 18 is high and the retard angle control oil passage 19 is low. The advance angle control oil passage 18 and the retard angle control oil passage 19 are formed as a straight hole by drilling (it can also be formed by casting).

  Needless to say, the other end 18b of the advance angle control oil passage 18 communicates with the advance angle annular groove 16a of the intake camshaft 11, and the other end 19b of the retard angle control oil passage 19 is The intake camshaft 11 communicates with the retard angle annular groove 16b. As clearly shown in FIGS. 4 and 6A, since the OCV 13 is located below the intake front bearing portion 5, the control oil passages 18 and 19 have a low start end and a high end. It is inclined to.

  As shown in FIGS. 5 and 9, one end 18 a of the advance angle control oil passage 18 and one end 19 a of the retard angle control oil passage 19 are open on the inner peripheral surface in front of the OCV mounting hole 12. One end 19a of the retard angle control oil passage 19 is located on the back side. Further, one end 18 a of the advance angle control oil passage 18 is positioned slightly higher than one end 19 a of the retard angle control oil passage 19. In FIGS. 4 and 9, one end 18a, 19a of the oil passage should originally be drawn with a dotted line, but is painted black for easy understanding.

  The advance angle control oil passage 18 and the advance angle control oil passage 18 are inclined so as to become lower from the intake front bearing portion 5 in a front view, and from the intake front bearing 5 in a plan view. As shown in FIGS. 5 and 9, they are inclined so as to shift backward as they move away, but due to the relationship between the front and rear positions, the left and right positions, and the heights of the one ends 18 a and 19 a and the other ends 18 b and 19 b The posture is such that it intersects with a substantially V shape both in view and in plan view.

  As shown in FIG. 6A, the intake camshaft 11 is rotatably held by the intake front bearing portion 5 by an intake front cam cap 21. As shown in FIG. 6B, an annular groove 22 is formed on the inner peripheral surface of the intake front cam cap 21, which is a lubricating groove.

  As described above, the intake front bearing portion 5 protrudes greatly in front of the front wall portion 2. Therefore, as can be understood from FIG. 6, about half of the advance angle control oil passage 18 is located in front of the front wall portion 2, and the retard angle control oil passage 19 is also located on the front end surface of the front wall portion 2. It is close. Therefore, as shown in FIGS. 1, 2, and 4, on the front surface of the front wall portion 2, it corresponds to the advance angle oil passage boss portion 23 corresponding to the advance angle control oil passage 18 and the retard angle control oil passage 19. The retarded oil passage boss portion 24 is formed in an inclined posture.

  Since the advance angle control oil passage 18 partially protrudes in front of the front wall portion 2, the advance oil passage boss portion 23 protrudes greatly from the front surface of the front wall portion 2, while the retard angle control oil. Since there is almost no protruding amount of the path 19, the protruding dimension of the retard oil path boss portion 24 is small. Further, regarding the height position, the retard oil passage boss portion 24 corresponds to the advance oil passage boss portion 23 corresponding to the advance angle control oil passage 18 being high and the retard angle control oil passage 19 being low. Is lower than. When both the oil passages 18 and 19 are at the same height, one boss portion is sufficient.

  As shown in FIGS. 1, 2, 4, and 6 (A), on the front surface of the front wall portion 2, on the opposite side of the oil passage boss portions 23, 24 (right side) across the axis of the intake front bearing portion 5 ), A counter rib 25 inclined symmetrically with the oil passage bosses 23 and 24 is provided to project forward. The counter rib 25 is connected to the intake front bearing portion 5, and the oil passage boss portions 23, 24 and the counter rib 25 are roughly in a C shape in front view.

  The OCV 13 needs to supply and discharge oil. This point will be described next. As shown in FIG. 9A, the oil supply hole is composed of a horizontal hole 26a extending in the cam axis direction and a vertical hole 26b having a vertically long posture. That is, the horizontal hole 26 a is formed below the OCV mounting hole 12, and the vertical hole 26 b is formed so as to communicate with the horizontal hole 26 a and the OCV mounting hole 12.

  As shown in FIG. 2 and FIG. 4, an oil reservoir 26c is formed in the front surface of the cylinder head 1 at an obliquely lower portion of the horizontal hole 26a. The oil is supplied through the branch passage 26d (see FIG. 4) and the longitudinal longitudinal hole.

  The oil reservoir 26c is closed by a chain guide tensioner 34 shown in FIG. 10, and the oil reservoir 26c and the oil reservoir 26c are horizontally aligned by an inclined communication hole 26e (see FIGS. 4 and 10) formed in the tensioner 34. The hole 26a is in communication. Thus, if the chain guide tensioner 34 is used as a part of the oil passage, the structure can be simplified and the cost can be reduced and the weight can be reduced. The communication hole 26e may be formed inside the tensioner 34, or may be formed on one or both of the mating surfaces of the cylinder head 1 and the tensioner 34.

  In the OCV 13, when oil is supplied to the advance angle control oil passage 18, oil in the retard angle working chamber is discharged, and when oil is supplied to the retard angle control oil passage 19, The oil in the working chamber is discharged. Therefore, although two front and rear discharge holes are provided, the front discharge hole communicates with the first drain hole 27 formed in the bottom of the OCV mounting hole 12 as shown in FIG. 9A. .

  The first drain hole 27 is long in the cam axis direction and is open to the front surface of the cylinder head 1. Then, the first drain hole 27 remains open from the front surface, and the oil flows down to the chain chamber. Therefore, the timing chain 31 can be used for lubrication.

  As shown in FIG. 7 and FIG. 9A, the discharge hole 13 a provided in the rear part of the OCV 13 is open to a void 1 a formed in the cylinder head 1. The oil that has flowed down into the empty space 1a returns to the oil pan through an oil pit (not shown). In FIG. 7 and FIG. 9 (A), the rear discharge hole 13a is shown downward, but it may be opened backward and allowed to flow down from the lateral hole formed in the OCV attachment hole 12 to the space 1a.

(3) Summary Since the control oil passages 18 and 19 are formed as a straight hole in the cylinder head 1, when formed by cutting, simple drilling may be used. Therefore, in the process of finishing the bearing hole made up of the intake front cam cap 21 and the intake front bearing portion 5 with the intake front cam cap 21 fixed, powder enters the control oil passages 19, 19. However, it can be easily removed by jetting compressed air.

  That is, since the control oil passages 18 and 19 are straight and the inner surface is smoothed by drilling, the chips are controlled even if the chip-like chips enter in an elastically deformed state or a dango-like state. The oil passages 18 and 19 are not easily caught on the inner surfaces (the friction is small), and are therefore easily eliminated by the pressure of the compressed air injection.

  Therefore, the labor of processing can be reduced, and the chips are not clogged and the OCV 13 or the VVT device does not malfunction. After finishing the bearing holes, the front cam cap 21 is removed and then both are cleaned with cleaning oil, and then the remaining chips are removed by jetting compressed air (in some cases, cleaning is performed). A deburring step may be provided in advance.)

  Further, since the boss portions 23 and 24 are provided on the front surface of the cylinder head 1, the control oil passages 18 and 19 protrude from the front of the front wall portion 2 or close to the front surface of the front wall portion 2. However, the control oil passages 18 and 19 can be formed without hindrance. Accordingly, it is not necessary to change the design of the cylinder head 1 or to change the arrangement position of the OCV 13, and the design freedom is high.

  Moreover, although the cylinder head 1 is an aluminum casting product, the cavity of the mold is enlarged by the boss portions 23 and 24, so that the flow of the molten metal in the mold becomes good, which can contribute to the improvement of the casting quality.

  Furthermore, since the boss portions 23 and 24 protrude from the front surface of the cylinder head 1, the rigidity of the cylinder head 1 can be improved by the rib effect. In this case, since the counter rib 25 is provided symmetrically with the boss portions 23 and 24, the rigidity of the intake front bearing portion 5 and its peripheral portion is made uniform. Therefore, when a mechanical external force is applied due to the circulation of the timing chain or thermal expansion occurs, distortion is prevented from occurring, and smooth rotation of the intake camshaft 11 can be maintained.

  As shown in FIG. 5, in the present embodiment, the control oil passages 18 and 19 are inclined so as to be displaced rearward from the intake front bearing portion 5 toward the OCV 13 in a plan view. Therefore, the OCV 13 can be disposed behind the front surface of the cylinder head 1 while the intake front bearing portion 5 projects forward. Therefore, it is not necessary to provide the cylinder head 1 with a forward-facing boss portion for arranging the OCV 13. Therefore, an increase in size and weight of the cylinder head 1 can be prevented.

  Further, in the present embodiment, the control oil passages 18 and 19 are opened on the inner peripheral surface of the intake front bearing portion 5 at different heights. By changing the height, the distance can be increased without increasing the distance in the front-rear direction. Therefore, it is possible to prevent a decrease in strength due to the provision of the two control oil passages 18 and 19.

  In the illustrated embodiment, the advance angle control oil passage 18 and the retard angle control oil passage 19 are formed. However, when the cam is used only for advance angle control or only for retard angle control, there is only one control oil passage. Good. The present invention can also be applied to an exhaust camshaft.

  The present invention can be embodied in an internal combustion engine equipped with a VVT device. Therefore, it can be used industrially.

DESCRIPTION OF SYMBOLS 1 Cylinder head 2 Front wall part 3, 4 Side wall part 5 Intake front bearing part 11 Intake camshaft 12 OCV mounting hole 13 OCV (oil control valve)
15 Longitudinal passage for advance angle 16a Annular groove for advance angle 16b Annular groove for retard angle 18 Oil path for advance angle control 19 Oil path for retard angle control 21 Front cam cap for intake 23 Boss portion for advance angle oil path 24 Delay angle oil Road boss 25 Counter rib 26 Oil supply hole 27 Oil discharge hole (drain hole)

Claims (4)

A camshaft that is rotatable relative to the chain sprocket by a hydraulic VVT device is rotatably held via a cam cap on a plurality of bearings of the cylinder head, and an oil control valve that controls the VVT device includes: Of the cylinder head, the front part close to the chain sprocket is attached to the outside of the front bearing part that rotatably supports the camshaft,
A control oil passage for controlling the VVT device is formed at the front of the cylinder head so that one end communicates with the oil control valve and the other end opens on the inner peripheral surface of the front bearing portion. is doing,
Internal combustion engine. The control oil passage is composed of two oil passages, that is, an advance control oil passage and a retard control oil passage, and these two control oil passages are provided on the camshaft. Formed as a straight hole apart in the axial direction,
The internal combustion engine according to claim 1. The front bearing portion protrudes forward from the front wall portion of the cylinder head, and an oil passage boss for forming the control oil passage on the front surface of the cylinder head and below the front bearing portion. The part protrudes forward,
The internal combustion engine according to claim 1 or 2. The control oil passage and the oil passage boss portion are inclined so as to become lower from the front bearing portion toward the oil control valve, and are seen from the axial direction of the camshaft on the front surface of the cylinder head. Counter ribs that are symmetrical with oil passage ribs are formed,
The internal combustion engine according to claim 3.

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