JP2542111Y2 - Engine cylinder head structure - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylinder head structure of an engine.

[0002]

2. Description of the Related Art In recent years, in a DOHC engine, both camshafts are interlocked via gears or the like as shown in Japanese Utility Model Laid-Open No. 63-150008, and only one camshaft is phase-adjusted to the front end thereof. A cam pulley is mounted via a device, and the phase difference between the cam pulley and the camshaft is changed by the phase adjusting device so that the opening / closing timing of a valve can be controlled.

In such an engine, when a rotation sensor such as a distributor or a crank angle sensor is mounted on the rear side, the rotation sensor detects rotation corresponding to the rotation of the camshaft. Is performed, an error occurs between the rotation state of the cam pulley corresponding to the actual crank angle and the rotation detection result.

[0004]

In order to solve the above-mentioned problems of the prior art, the present applicant has filed Japanese Patent Application No. 2-247.
No. 889 was filed. In this prior application, an idle pulley that rotates in synchronization with the cam pulley is disposed in front of a camshaft on which the cam pulley is not attached, and a detector is provided on the idle pulley and a rotation that detects the rotation of the detector is provided. An engine rotation sensor mounting structure that can accurately detect engine rotation without being affected by the operation of a phase adjustment device by providing a sensor on a cover is described.

In the prior application having such a structure, since the torque of the timing pulley is transmitted to the idle pulley via the timing belt, it is necessary to increase the rigidity of attachment to the cylinder head. Further, since the idle pulley is provided with a detector and a rotation sensor for detecting the rotation of the detector is provided on the cover, it is necessary to reduce the intrusion of dust into the rotation sensor.

Accordingly, the present invention is a further improvement of the above-mentioned prior application, and an object of the present invention is to provide a cylinder head structure of an engine in which the rigidity of mounting an idle pulley to a cylinder head is increased. Another object of the present invention is to provide a cylinder head structure in which dust is prevented from entering the rotation sensor.

[0007]

According to the present invention, in order to achieve the above object, an intake side camshaft and an exhaust side camshaft are arranged in a cylinder head, and a cam pulley is attached to one of these camshafts. An idle pulley mounting boss portion formed so as to protrude forward from a portion of the cylinder head where the idle pulley is mounted, wherein the idle pulley is rotatably mounted in front of the other camshaft; A transmission mechanism for transmitting power from one side of the camshaft to the other, and an oil return passage for oil for lubricating the transmission mechanism are formed, and are located near the idle pulley mounting boss and bulge forward of the cylinder head. And a passage wall formed so as to perform

In the present invention configured as described above,
Since a mounting boss portion for an idle pulley is formed to protrude forward at a portion where the idle pulley of the cylinder head is mounted, and a passage wall swelling forward of the cylinder head is formed near the mounting boss portion for the idle pulley,
The mounting rigidity required for mounting the idle pulley to the cylinder head can be increased.

In the present invention, a detector attached to the idle pulley and a rotation sensor attached to an inner surface of a cover covering the idle pulley for detecting rotation of the detector may be further provided. In the present invention configured as described above, since the passage wall and the mounting boss portion for the idle pulley both protrude forward of the cylinder head, the space between these and the opposing side surface of the idle pulley is reduced, and the rotation sensor is connected to the rotation sensor. Dust is reduced. In the present invention, the idle pulley mounting boss may be formed so as to protrude toward the inner diameter side of the idle pulley. In the present invention configured as described above, by utilizing the space formed on the inner diameter side of the idle pulley, it is possible to reduce the size and secure the rigidity. Furthermore, in the present invention, the passage wall is
It may be located below the idle pulley mounting boss and be formed continuously through the idle pulley mounting boss and the connecting portion.

[0010]

1 to 4 show an embodiment of the present invention.
This will be described with reference to FIG. FIG. 1 is a sectional plan view showing an embodiment of the present invention. In FIG. 1, reference numeral 10 denotes a cylinder head of an engine, in which an intake camshaft 12 and an exhaust camshaft 14 extending in the front-rear direction (vertical direction in the figure) of the engine are rotatably supported. Have been. Each of the intake camshaft 12 and the exhaust camshaft 14 has a cam 1
6 and 18 are formed, and sprockets 20 and 22 are fixed at appropriate positions, respectively. A tension adjusting device 24 is provided between the sprockets 20 and 22. The sprockets 20 and 22 are connected by a chain 26 via the tension adjusting device 24, and the sprockets 20 and 22 mutually move. It is designed to rotate.

A cam pulley 30 is attached to the front end of the intake camshaft 12 via a phase adjusting device 28. The phase adjusting device 28 is connected to the intake camshaft 12.
And the cam pulley 30 is appropriately shifted in phase to adjust the valve opening / closing timing to an appropriate timing. On the front end surface of the cylinder head 10 located at the front end of the exhaust side camshaft 14, an idle pulley mounting boss 32 protruding forward is formed. The mounting boss portion 32 for the idle pulley is formed so as to protrude toward the inner diameter side of the idle pulley 40. By utilizing a space formed on the inner diameter side of the idle pulley, the mounting boss portion 32 is made compact and secures rigidity. ing. Next, an idle pulley support member 34 is fixed to the idle pulley mounting boss 32 with bolts 36. An idle pulley 40 is rotatably mounted on the idle pulley support member 34 via a bearing 38. On the front side surface of the idle pulley 40, two ring-shaped shielding plates (detectors) 4 having different diameters are provided.
2 and 44 are fixed coaxially with the idle pulley 40. A large number of openings (not shown) are formed in each of these shielding plates 42 and 44 in the circumferential direction.

On the other hand, a timing pulley 46 as shown in FIG. 2 is fixed to the lower end of the engine at the front end of the crankshaft, and a timing belt 48 is attached to the timing pulley 46, the cam pulley 30, and the idle pulley 40. Has been passed over. The timing belt 48 is given an appropriate tension by tension pulleys 50 and 52.

The cam pulley 30 and the idle pulley 40 are covered by syringe head covers 54 and 56 disposed in front of the engine.
A disk-shaped cover 58 is provided at a position corresponding to the above, and the cover 58 and the idle pulley support member 34 are aligned. As shown in FIG. 1, two rotation sensors 60 and 62 are attached to the inner surface of the cover 58.
These rotation sensors 60 and 62 are configured by transmission type optical switches. The rotation sensor 60 is provided at a position sandwiching the opening formed in the shielding plate 42 from both sides with a predetermined minute interval therebetween. The rotation sensor 62 includes a light emitting element 60a and a light receiving element 60b, and a light emitting element 62a and a light receiving element 62b provided at a position sandwiching an opening formed in the shielding plate 44 from both sides at a predetermined minute interval.
have.

FIG. 3 is a front view showing the cylinder head 10.
FIG. 4 is a plan view showing the cylinder head 10. As shown in FIGS. 3 and 4, the cylinder head 10
Inside, an oil return passage 64 for oil lubricating the sprockets 20, 22 and the chain 26 is formed. Reference numeral 66 denotes a passage wall which forms a part of the oil return passage 64. The passage wall 66 is located near the idle pulley mounting boss 32 and swells forward of the cylinder head 10. Is formed. Here, the passage wall 66 may be in the vicinity of the idle pulley mounting boss portion 32, may be in a position close to the idle pulley mounting boss portion 32, and may be continuous through the connecting portion 67 as shown in the drawing. It may be formed.
Reference numeral 68 denotes a passage wall of an oil passage for supplying lubricating oil to each bearing of the intake side camshaft 12 and the exhaust side camshaft 14.
Is formed so as to protrude forward from a front end side wall of the passage wall 6.
6, which contributes to improving the rigidity of the front end side wall of the cylinder head 10.

Next, the operation will be described. Timing pulley 4
6 is transmitted to the cam pulley 30 and the idle pulley 40 via the timing belt 48, whereby the pulleys 30 and 40 are always driven with a constant phase difference. The rotation of the cam pulley 30 is transmitted to the intake-side camshaft 12 via the phase adjusting device 28, whereby the two camshafts 12, 14 are driven synchronously.

On the other hand, with the rotation of the idle pulley 40, the two shield plates 42, 44 rotate integrally, so that the light emitting element 60 in each of the rotation sensors 60, 62.
Light emitted from the light receiving elements 60b and 62b from the light receiving elements 60a and 62b is intermittently shielded. Thereby, each rotation sensor 6
Numerals 0 and 62 can detect the rotational position of the idle pulley 40.

Since the torque of the timing pulley 46 is transmitted to the idle pulley 40 by the timing belt 48, it is necessary to increase the rigidity of attachment to the cylinder head 10. In this embodiment, an idle pulley mounting boss 32 protruding forward is formed on the front end face of the cylinder head 10, and an idle pulley support member 34 is fixed to the idle pulley mounting boss 32 with a bolt 36. Therefore, sufficient mounting rigidity can be secured. Further, since the passage wall 66 which forms a part of the oil return passage 64 is located near the idle pulley mounting boss portion 32 and is formed so as to bulge forward of the cylinder head 10, the idle pulley The rigidity around the lower portion of the mounting boss portion 32 is improved, so that the deformation of this portion is suppressed.

In this embodiment, a passage wall 66 forming a part of the oil return passage 64 is formed so as to be located near the idle pulley mounting boss 32 and to protrude forward of the cylinder head 10. Have been. Therefore, since both the passage wall 66 and the idle pulley mounting boss 32 project forward of the cylinder head 10, the space between these and the opposing side surface of the idle pulley 40 is reduced. As a result, dust that moves with the rotation of the idle pulley 40 collides with the passage wall 66 and the mounting boss 32 for the idle pulley, and falls downward. Therefore, it is possible to prevent dust from entering the rotation sensors 60 and 62. Thereby, each rotation sensor 6
The accuracy of 0 and 62 can be improved.

[0019]

As described above, according to the present invention, the rigidity required for mounting the idle pulley to the cylinder head can be increased. Further, since the intrusion of dust into the rotation sensor can be prevented, the accuracy of the rotation sensor can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional plan view showing one embodiment of a cylinder head structure of an engine of the present invention.

FIG. 2 is a schematic front view showing an embodiment of the present invention.

FIG. 3 is a front view showing a cylinder head.

FIG. 4 is a plan view showing a cylinder head.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Cylinder head 12 Intake side camshaft 14 Exhaust side camshaft 20 Sprocket 22 Sprocket 26 Chain 30 Cam pulley 32 Idle pulley attachment boss part 40 Idle pulley 42 Shielding plate (detector) 44 Shielding plate (detector) 54 Head cover 56 Head cover 58 Cover 60 rotation sensor 62 rotation sensor 64 oil return passage 66 passage wall

Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical display location F02D 35/00362 F02D 35/00 362G (56) References JP-A-61-232305 (JP, A) JP-A-61-232305 Hei 3-100308 (JP, A) Fully open 63-10008 (JP, U) Fully open 63-21707 (JP, U) Fully open 61-101608 (JP, U) Really open 60-2713 (JP , U) Japanese Utility Model Showa 62-162319 (JP, U)

Claims (5)

(57) [Scope of request for utility model registration] An intake camshaft and an exhaust camshaft are arranged in a cylinder head, and a cam pulley is mounted on one of the camshafts and an idle pulley is rotatably mounted in front of the other camshaft. In the cylinder head structure of the engine, a mounting boss portion for an idle pulley formed to protrude forward from a portion where the idle pulley of the cylinder head is mounted, and a transmission mechanism for transmitting power from one of the camshafts to the other. And a passage wall formed near the mounting boss portion for the idle pulley and formed so as to bulge forward of the cylinder head, forming an oil return passage for oil for lubricating the transmission mechanism. Engine cylinder head structure. 2. The apparatus according to claim 1, further comprising: a detector attached to the idle pulley; and a rotation sensor attached to an inner surface of a cover that covers the idle pulley and configured to detect rotation of the detector. Engine cylinder head structure. 3. The engine cylinder head according to claim 1, wherein the transmission mechanism is a sprocket fixed to the intake camshaft and the exhaust camshaft, respectively, and a chain connecting the sprockets. Construction. 4. The engine cylinder head structure according to claim 1, wherein said idle pulley mounting boss is formed so as to protrude toward an inner diameter side of said idle pulley. 5. The method according to claim 5, wherein the passage wall is located below the idle pulley mounting boss and is formed continuously with the idle pulley mounting boss via a connection portion. 2. The cylinder head structure of the engine according to 1.