JP2021063483A - Internal combustion engine valve timing control apparatus - Google Patents

Abstract

To suppress oil from leaking from an internal combustion engine side and the opposite side.SOLUTION: An internal combustion engine valve timing control apparatus changes valve timing by changing a rotation phase of a cam shaft relative to a crank shaft by hydraulic pressure. The control apparatus includes: a first rotary body allowing the cam shaft to go through; a rotor that has a protrusion part protruding toward the engine and the opposite side, the part having its center concentric with a rotation axis of the cam shaft; and a second rotary body, including an opening allowing the protrusion part to be loosely fit in, for forming a hydraulic pressure chamber to be supplied with oil, by sandwiching the rotor with the first rotary body.SELECTED DRAWING: Figure 3

Description

The present invention relates to a valve timing control device for an internal combustion engine.

A valve timing adjusting device including a rotating body that rotates synchronously with a crankshaft, which is an output shaft of an internal combustion engine, and a rotor that can rotate relative to the rotating body is known. The rotating body includes a sprocket that rotates integrally with the crankshaft, a case having a plurality of shoes protruding from the inner peripheral portion, and a cover that closes a plurality of hydraulic chambers composed of the shoes. The sprocket, case, and cover are integrated by fastening members such as bolts.

On the other hand, the rotor has a boss portion having a bearing portion that receives one end of the camshaft and a boss portion that protrudes outward in the radial direction from the outer peripheral portion of the boss portion. It is composed of a plurality of vanes that are partitioned into a hydraulic chamber. Hydraulic oil (hereinafter referred to as oil) is supplied to the advancing side hydraulic chamber and the retarding side hydraulic chamber, respectively (see Patent Document 1 above).

Japanese Unexamined Patent Publication No. 2003-120230

By the way, the above-mentioned cover closes the hydraulic chamber from the side opposite to the internal combustion engine side, but the cover cannot completely close the hydraulic chamber because it is fastened by the fastening member. As a result, a clearance in the shaft direction is generated between the cover and the case and the rotor. Therefore, for example, if the fluidity of the oil increases at a high temperature, the oil supplied to the advancing side hydraulic chamber and the retarding side hydraulic chamber may leak through this clearance. That is, oil leakage may occur from the side opposite to the internal combustion engine side. If an oil leak occurs and the oil pressure in the hydraulic chamber drops, the responsiveness of the valve timing adjusting device deteriorates, and the stability of operation may be lost.

Therefore, an object of the present invention is to suppress oil leakage from the side opposite to the internal combustion engine side.

The valve timing control device for an internal combustion engine according to the present invention is a valve timing control device for an internal combustion engine that changes the valve timing by changing the rotation phase of the camshaft with respect to the crankshaft by hydraulic pressure, through which the camshaft is inserted. A hydraulic chamber that includes a first rotating body, a rotor that includes a protruding portion that protrudes from the internal combustion engine side to the opposite side of the rotating shaft of the camshaft, and an opening that fits the protruding portion in a gap, and oil is supplied. Has a second rotating body formed by sandwiching the rotor together with the first rotating body.

According to the present invention, oil leakage from the side opposite to the internal combustion engine side can be suppressed.

FIG. 1 is an example of an internal combustion engine. FIG. 2 is an example of a perspective view of the VVT mechanism. FIG. 3 is an example of a cross-sectional view taken along the line AA of the VVT mechanism. FIG. 4 is an example of a cross-sectional view taken along the line BB of the VVT mechanism. FIG. 5 is another example of a perspective view of the VVT mechanism. FIG. 6 is an example of a CC cross-sectional view of the VVT mechanism. FIG. 7 is an example of a DD cross-sectional view of the VVT mechanism.

Hereinafter, the first embodiment and the second embodiment for carrying out the present invention will be described with reference to the drawings. In particular, in the first embodiment, a sprocket is adopted as an example of the first rotating body, and a housing is adopted as an example of the second rotating body. On the other hand, in the second embodiment, the housing and the rear plate are adopted as an example of the first rotating body, and the front plate is adopted as an example of the second rotating body. Further, in the first embodiment and the second embodiment, the internal combustion engine side of the VVT mechanism is referred to as the rear side, and the side opposite to the internal combustion engine side is referred to as the front side with reference to the VVT mechanism. The VVT mechanism is an example of a valve timing control device.

(First Embodiment)
FIG. 1 is an example of an internal combustion engine 40. As shown in FIG. 1, the intake passage 2 and the exhaust passage 3 are connected to the combustion chamber 1 of the internal combustion engine 40. An intake valve 4 is provided between the combustion chamber 1 and the intake passage 2. An exhaust valve 5 is provided between the combustion chamber 1 and the exhaust passage 3. The intake valve 4 and the exhaust valve 5 are constantly urged in the valve closing direction by valve springs 6 and 7, respectively.

The internal combustion engine 40 is provided with an intake camshaft 9 having an intake cam 8 for pushing down the intake valve 4 to open and close it. Further, the internal combustion engine 40 is provided with an exhaust camshaft 11 having an exhaust cam 10 for pushing down the exhaust valve 5 to open and close it. As described above, the internal combustion engine 40 includes the intake camshaft 9 and the exhaust camshaft 11.

A hydraulic VVT (Variable Valve Timing) mechanism 100 is provided at one end of the intake camshaft 9. The VVT mechanism 100 can be adopted as a valve timing control device. The VVT mechanism 100 changes the valve timing of the intake valve 4 by hydraulically changing the rotation phase of the intake camshaft 9 with respect to the crankshaft 13. The VVT mechanism 100 has an OCV (Oil Control Valve) 101 that adjusts the supply and discharge mode of oil to the VVT mechanism 100. Although details will be described later, the VVT mechanism 100 is provided with a sprocket 102 and a housing 103 separate from the sprocket 102.

A timing chain 15 is wound around the sprocket 102, the sprocket 12 attached to the exhaust camshaft 11, and the sprocket 14 attached to the crankshaft 13. Therefore, the internal combustion engine 40 includes a crankshaft 13 and a timing chain 15. When the crankshaft 13 rotates, the intake camshaft 9 and the exhaust camshaft 11 rotate in synchronization with the rotation of the crankshaft 13. As a result, the intake valve 4 and the exhaust valve 5 are pushed down by the intake cam 8 and the exhaust cam 10, respectively, and are opened and closed.

Further, the crankshaft 13 is connected to the oil pump 18 via a timing belt 16. The oil pump 18 is driven by the rotation of the crankshaft 13, pumps the oil stored in the oil pan 20, and supplies the pumped oil to the VVT mechanism 100 through the OCV 101.

Subsequently, the details of the VVT mechanism 100 according to the first embodiment will be described with reference to FIGS. 2 to 4.

FIG. 2 is an example of a perspective view of the VVT mechanism 100. FIG. 3 is an example of a cross-sectional view taken along the line AA of the VVT mechanism 100. FIG. 4 is an example of a cross-sectional view taken along the line BB of the VVT mechanism 100. The VVT mechanism 100 includes a sprocket 102, a housing 103, and a rotor 104, as shown in FIG. The housing 103 is fastened to the sprocket 102 by a fastening member (not shown) such as a bolt.

From the viewpoint of ensuring strength, it is desirable that the sprocket 102 is made of a heavy metal such as iron. On the other hand, the materials of the housing 103 and the rotor 104 are not limited to heavy metals. A heavy metal may be used as the material of the housing 103 and the rotor 104, or a light metal such as aluminum may be used. If the housing 103 and the rotor 104 are made of different materials, the housing 103 or the rotor 104 may be deformed due to the difference in thermal expansion. Therefore, it is desirable that the housing 103 and the rotor 104 are made of the same material.

As shown in FIG. 3, the housing 103 has a front disk portion 103a and a front cylinder wall portion 103b extending from the outer circumference of the front disk portion 103a toward the rear side. In particular, as shown in FIGS. 2 and 3, the front disk portion 103a has a circular opening 103x in the central portion. That is, it can be said that the housing 103 has a box shape in which a circular hole smaller than the circular hole is provided in the central portion of the circular bottom surface. As shown in FIG. 4, a plurality of shoes 103y projecting in the central direction are arranged on the inner peripheral surface of the front cylinder wall portion 103b of the housing 103.

On the other hand, as shown in FIG. 3, the sprocket 102 has a rear disc portion 102a having a diameter larger than the outer circumference of the front disc portion 103a, and a rear cylinder wall portion 102b and a rear cylinder wall extending from the outer circumference of the rear disc portion 102a toward the front side. It has a gear portion 102c provided on the outer circumference of the portion 102b. In particular, the rear disk portion 102a has a circular opening 102x in the central portion. The intake camshaft 9 is inserted into the opening 102x of the rear disk portion 102a. As described above, the sprocket 102 has a box shape in which a circular hole smaller than the circular hole is provided in the central portion of the bottom surface of the circular shape, and a plurality of teeth are arranged around the edge of the box.

As shown in FIGS. 2 and 3, most of the rotor 104 is housed inside the sprocket 102 and the housing 103. That is, as shown in FIG. 3, most of the rotor 104 is sandwiched between the sprocket 102 and the housing 103. As shown in FIG. 4, the rotor 104 has a boss portion 104a and a plurality of vanes 104b. The plurality of vanes 104b are provided on the outer peripheral surface of the boss portion 104a. Each vane 104b divides a plurality of hydraulic chambers surrounded by the inner peripheral surface of the front cylinder wall portion 103b, the outer peripheral surface of the boss portion 104a, and the two shoes 103y into an advance side hydraulic chamber R1 and a retard side hydraulic chamber R2, respectively. To do.

As shown in FIG. 4, a chip seal 104z is provided at a portion of the boss portion 104a facing the tip portions of the plurality of shoes 103y. The tip seal 104z comes into contact with the respective tips of the plurality of shoes 103y. Oil is supplied to the advance side hydraulic chamber R1 and the retard side hydraulic chamber R2, respectively. By providing the tip seal 104z on the boss portion 104a, the advance side hydraulic chamber R1 passes through the outer peripheral surface of the boss portion 104a. It is possible to suppress oil leakage from one of the retard side hydraulic chambers R2 to the other.

Further, as shown in FIG. 4, a tip seal 104z is also provided at the tip of each vane 104b of the rotor 104. Each chip seal 104z comes into contact with the inner peripheral surface of the front cylinder wall portion 103b of the housing 103 facing them (see also FIG. 3). As described above, oil is supplied to the advancing side hydraulic chamber R1 and the retarding side hydraulic chamber R2, respectively. By providing the tip seal 104z on each vane 104b, the inner peripheral surface of the front cylinder wall portion 103b can be provided. It is possible to suppress oil leakage from one of the advance angle side hydraulic chamber R1 and the retard angle side hydraulic chamber R2 to the other.

Further, as shown in FIGS. 2 and 3, the rotor 104 includes a substantially convex protruding portion 104c that protrudes toward the front side along the direction of the rotating shaft P about the rotating shaft P of the intake camshaft 9. .. The protrusion 104c is gap-fitted into the opening 103x of the housing 103. As a result, the inner peripheral surface of the front disk portion 103a of the housing 103 becomes a bearing structure with respect to the outer peripheral surface of the protruding portion 104c of the rotor 104. Here, as described above, since the housing 103 is fastened to the sprocket 102 by the fastening member, as shown in FIG. 3, in the direction of the rotation axis P of the intake camshaft 9 between the housing 103 and the rotor 104. A stretching clearance 70 may occur. Since the clearance 70 is coupled to the advance side hydraulic chamber R1 (or the retard side hydraulic chamber R2) formed by sandwiching the rotor 104 between the sprocket 102 and the housing 103, the advance side hydraulic chamber R1 (or the retard angle) The oil supplied to the side hydraulic chamber R2) may leak through the clearance 70. However, as shown in FIG. 3, the protruding portion 104c is gap-fitted in the opening 103x and closes most of the opening 103x. That is, by realizing the bearing structure of the present embodiment, a clearance seal (non-contact type seal) that maintains a minute gap between the opening 103x and the protruding portion 104c is secured. As a result, the oil that could leak from the advance side hydraulic chamber R1 (or the retard side hydraulic chamber R2) through the clearance 70 in the absence of the protruding portion 104c is suppressed even if the oil fluidity increases. It becomes possible to do.

In particular, when the rotor 104 is manufactured from an extruded material in the present embodiment, as shown in a partially enlarged view of FIG. 3, a slope having a width C1 is formed at the base of the protruding portion 104c, and this slope is formed. It is desirable to form a slope having a width C2 larger than the width C1 also in the portion of the housing 103 facing the above. By making the width C2 larger than the width C1, it is possible to easily manufacture a bearing structure that does not interfere with the housing 103.

As described above, according to the first embodiment, the internal combustion engine 40 is provided with the VVT mechanism 100. The VVT mechanism 100 changes the valve timing by hydraulically changing the rotation phase of the intake camshaft 9 with respect to the crankshaft 13. In particular, the VVT mechanism 100 includes a sprocket 102, a rotor 104 and a housing 103. The intake camshaft 9 is inserted through the sprocket 102. The rotor 104 includes a protruding portion 104c that protrudes toward the front side about the rotation shaft P of the intake camshaft 9. The housing 103 includes an opening 103x for fitting the protrusion 104c in a gap, and forms an advance side hydraulic chamber R1 and a retard side hydraulic chamber R2 to which oil is supplied by sandwiching the rotor 104 together with the sprocket 102. As a result, even if the fluidity of the oil supplied to the advancing side hydraulic chamber R1 and the retarding side hydraulic chamber R2 increases, oil leakage from the front side can be suppressed.

(Second Embodiment)
Subsequently, the details of the VVT mechanism 100 according to the second embodiment will be described with reference to FIGS. 5 to 7.

FIG. 5 is another example of a perspective view of the VVT mechanism 100. FIG. 6 is an example of a CC cross-sectional view of the VVT mechanism 100. FIG. 7 is an example of a DD cross-sectional view of the VVT mechanism 100. As shown in FIG. 5, the VVT mechanism 100 includes a rotor 105, a housing 106, a front plate 107, and a rear plate 108. The front plate 107 is fastened to the housing 106 and the rear plate 108 by fastening members (not shown) such as bolts.

The sprocket 109 can be integrally formed with the housing 106, as shown in FIG. Instead of the housing 106, the sprocket 109 may be integrally formed with the rear plate 108. The materials of the rotor 105, the housing 106, the front plate 107, the rear plate 108, and the sprocket 109 are all heavy metals.

As shown in FIGS. 5 and 6, the front plate 107 is a disk having a circular opening 107x in the central portion. Further, as shown in FIG. 6, the rear plate 108 is a disk having a circular opening 108x in the central portion. The intake camshaft 9 is inserted through the opening 108x of the rear plate 108. On the other hand, as shown in FIGS. 6 and 7, the housing 106 is a cylinder in which a sprocket 109 is formed on an outer peripheral surface. As shown in FIG. 7, a plurality of shoes 106y projecting in the central direction are arranged on the inner peripheral surface of the housing 106.

As shown in FIGS. 5 and 6, most of the rotor 105 is housed inside the housing 106 and is sandwiched between the front plate 107 and the rear plate 108. As shown in FIG. 7, the rotor 105 has a boss portion 105a and a plurality of vanes 105b. The plurality of vanes 105b are provided on the outer peripheral surface of the boss portion 105a. A plurality of hydraulic chambers surrounded by the inner peripheral surface of each vane 105b, the outer peripheral surface of the boss portion 105a, and the two shoes 106y are divided into an advance side hydraulic chamber R1 and a retard side hydraulic chamber R2, respectively.

As shown in FIG. 7, a tip seal 105z is provided at a portion of the boss portion 105a facing the tip portions of the plurality of shoes 106y. The tip seal 105z comes into contact with the respective tips of the plurality of shoes 106y. By providing the tip seal 105z on the boss portion 105a, it is possible to suppress oil leakage from one of the advance angle side hydraulic chamber R1 and the retard angle side hydraulic chamber R2 to the other via the outer peripheral surface of the boss portion 105a.

Further, as shown in FIG. 7, a tip seal 105z is also provided at the tip of each vane 105b of the rotor 105. Each chip seal 105z abuts on the inner peripheral surface of the housing 106 facing them (see also FIG. 6). By providing the tip seal 105z on each vane 105b, it is possible to suppress oil leakage from one of the advancing side hydraulic chamber R1 and the retarding side hydraulic chamber R2 to the other via the inner peripheral surface of the housing 106.

Further, as shown in FIG. 6, the rotor 105 includes a substantially convex protruding portion 105c that protrudes toward the front side along the direction of the rotating shaft P about the rotating shaft P of the intake camshaft 9. The protrusion 105c is gap-fitted into the opening 107x of the front plate 107. As a result, the inner peripheral surface of the front plate 107 becomes a bearing structure with respect to the outer peripheral surface of the protruding portion 105c of the rotor 105. Here, as described above, since the front plate 107 is fastened to the housing 106 and the rear plate 108 by the fastening member, as shown in FIG. 6, the intake camshaft 9 is between the front plate 107 and the rotor 105. A clearance 80 extending in the direction of the axis P may occur. Since the clearance 80 is coupled to the advance side hydraulic chamber R1 (or the retard side hydraulic chamber R2) formed by sandwiching the rotor 105 between the front plate 107 and the rear plate 108, the advance side hydraulic chamber R1 (or the clearance 80) The oil supplied to the retard side hydraulic chamber R2) may leak through the clearance 80. However, as shown in FIG. 6, the protrusion 105c is gap-fitted in the opening 107x to close most of the opening 107x. That is, by realizing the bearing structure of the present embodiment, a clearance seal that maintains a minute gap between the opening 107x and the protruding portion 105c is secured. As a result, the oil that could leak from the advance angle side hydraulic chamber R1 (or the retard angle side hydraulic chamber R2) through the clearance 80 in the absence of the protruding portion 105c is suppressed even if the oil fluidity increases. It becomes possible to do.

In particular, when the rotor 105 is manufactured from a sintered material in the present embodiment, as shown in a partially enlarged view of FIG. 6, a groove is formed at the base of the protruding portion 105c due to molding from the mold. , A bearing structure that does not interfere with the housing 106 can be easily manufactured.

As described above, according to the second embodiment, the internal combustion engine 40 is provided with the VVT mechanism 100. The VVT mechanism 100 changes the valve timing by hydraulically changing the rotation phase of the intake camshaft 9 with respect to the crankshaft 13. In particular, the VVT mechanism 100 includes a rear plate 108, a rotor 105, and a front plate 107. The intake camshaft 9 is inserted into the rear plate 108. The rotor 105 includes a protruding portion 105c that protrudes toward the front side about the rotation shaft P of the intake camshaft 9. The front plate 107 includes an opening 107x for fitting the protrusion 105c in a gap, and forms an advance side hydraulic chamber R1 and a retard side hydraulic chamber R2 to which oil is supplied by sandwiching the rotor 104 together with the rear plate 108. As a result, even if the fluidity of the oil supplied to the advancing side hydraulic chamber R1 and the retarding side hydraulic chamber R2 increases, oil leakage from the front side can be suppressed.

Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the specific embodiments, and various modifications and modifications are made within the scope of the gist of the present invention described in the claims. It can be changed. For example, in the above-described embodiment, the VVT mechanism 100 is provided at one end of the intake camshaft 9, but the VVT mechanism 100 may be provided at one end of the exhaust camshaft 11.

Further, in the above-described embodiment, the tip seals 104z and 105z are provided on the boss portion 105a, but the tip seals 104z and 105z may be provided on the tip portions of the shoes 103y and 106y. If a clearance seal can be secured between the tip surface of the shoes 103y and 106y and the outer peripheral surface of the boss portion 104a, the tip seals on the shoes 103y and 106y are used to suppress an increase in the number of parts and simplify the structure. It is not necessary to provide 104z and 105z.

40 Internal combustion engine 70,80 Clearance 100 VVT mechanism 102,109 Sprocket 103,106 Housing 103x, 107x Opening 104,105 Rotor 104c, 105c Protruding part 107 Front plate 108 Rear plate R1 Advance side hydraulic chamber R2 Diagonal side hydraulic chamber

Claims (1)

A valve timing control device for an internal combustion engine that changes the valve timing by changing the rotation phase of the camshaft with respect to the crankshaft by flood control.
The first rotating body through which the camshaft is inserted and
A rotor including a protrusion that protrudes from the internal combustion engine side to the opposite side of the rotation axis of the camshaft.
A second rotating body formed by sandwiching the rotor together with the first rotating body, including an opening for fitting the protruding portion in a gap, and a hydraulic chamber to which oil is supplied.
Valve timing control device for internal combustion engines.

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