WO2006085640A1

WO2006085640A1 - Attachment structure of sensor for internal combustion engine and cam cap component

Info

Publication number: WO2006085640A1
Application number: PCT/JP2006/302423
Authority: WO
Inventors: Kazuya Yoshijima; Hiroki Morishita
Original assignee: Toyota Jidosha Kabushiki Kaisha
Priority date: 2005-02-10
Filing date: 2006-02-07
Publication date: 2006-08-17
Also published as: JP2006220073A

Abstract

A receiving portion 13 and a base of a cam cap component 8 are molded in one piece and firmly integrated. The base 12 functions as a cam cap. Accordingly, the position of a cam angle sensor 2 attached to the receiving portion 13 relative to a rotor 6 attached to an intake camshaft 4 is firmly and accurately determined. Deformation and vibration of a cylinder head cover 20, which are likely to occur since the cylinder head cover 20 is made of resin, are absorbed by a gasket 24 between an opening 22 of the cylinder head cover 20 and a sleeve 14. The deformation and vibration are therefore prevented from adversely influencing the positions of the sleeve 14 and the cam angle sensor 2. Therefore, the cam angle sensor 2 is capable of accurately detecting the cam angle without being influenced by vibrations and deformation of the cylinder head cover 20.

Description

DESCRIPTION

ATTACHMENT STRUCTURE OF SENSOR FOR INTERNAL COMBUSTION ENGINE

AND CAM CAP COMPONENT

TECHNICAL FIELD

The present invention relates to an attachment structure of sensors for an internal combustion engine such as cam angle sensors, and to a cam cap component to which function devices of an internal combustion engine such as sensors and oil control valves are attached.

BACKGROUND ART

An internal combustion engine equipped with a variable valve actuation mechanism needs to be provided with a cam angle sensor in the vicinity of a cam shaft to detect the state of the valve timing. Techniques for installing cam angle sensors include the one in which a cam angle sensor is attached to a cylinder head cover, and a rotor is attached to a cam shaft to face the cam angle sensor ( for example, refer to Japanese Patent No . 3551001) . The rotational phase of the rotor is detected by the cam angle sensor .

When an internal combustion engine is operating, the cylinder head cover is likely to vibrate . Particularly, in cases where a cylinder head cover is thin-walled or made of resin to reduce the weight of the internal combustion engine, vibrations are increased and the cylinder head cover may be deformed due to internal pressure and heat .

Accordingly, if the configuration disclosed in Japanese Patent No . 3551001 is applied to a thin-walled or resin cylinder head cover, vibrations of a cam angle sensor attached to the cylinder head cover can generate noise in cam angle detection signals . Also, the position of the cam angle sensor can be displaced by the vibration, resulting in a significantly degraded accuracy of the cam angle detection signals .

These problems are, not unique to cam angle sensors but also are found in other sensors used in internal combustion engines if such sensors are attached to a cylinder head cover and contact or face a component located between a cylinder head and the cylinder head cover .

DISCLOSURE OF THE INVENTION

Accordingly, it is an obj ective of the present invention to provide an attachment structure for sensors used in an internal combustion engine, which' structure eliminates influence of vibrations and deformations of a cylinder head cover on detection performed by the sensors . Another obj ective of the present invention is to provide a cam cap component that is capable of receiving function devices for internal combustion engines such as sensors and oil control valves and is applicable to the attachment structure .

To achieve the foregoing and other obj ectives and in accordance with the purpose of the present invention, an attachment structure of a sensor for an internal combustion engine is^' provided. The engine has a component that is located between a cylinder head and a cylinder head cover of the engine while being covered by the cylinder head cover . The sensor contacts or faces the component . Part of the sensor is exposed from an opening formed in the cylinder head . The attachment structure includes a receiving portion, a base, an oil seal member, and a fastening portion . The sensor is detachably attached to the receiving portion through the opening . The base is integrally formed with the receiving portion, and is fixed to the cylinder head to determine the position of the receiving portion relative to the cylinder head. The oil seal member seals a space between an opening forming portion, which is a portion of the cylinder head cover that forms the opening, and the receiving portion, or a space between the opening forming portion and the sensor . The fastening portion fastens the sensor to the receiving portion to maintain the attached state of the sensor to the receiving portion.

The present inventio also provides a cam cap component having a sleeve and a cam cap that are molded in one piece . The sleeve has a receiving hole to which a function device for an internal combustion engine is attached. The cam camp supports a camshaft of the engine .

Other aspects and advantages of the invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention .

BRIEF DESCRIPTION OF THE DRAWINGS

The invention, together with objects and advantages thereof, may best be understood by reference to the following description of the presently preferred embodiments together with the accompanying drawing in which :

Fig . 1 is a top perspective view illustrating an attachment structure of a cam angle sensor according to a first embodiment;

Fig . 2 is a bottom perspective view illustrating the attachment structure of the cam angle sensor shown in Fig . 1 ;

Fig. 3 is a front view illustrating the attachment structure of the cam angle sensor shown in Fig. 1; Fig . 4 is a right side view illustrating the attachment structure of the cam angle sensor shown in Fig . 1 ;

Fig . 5 is a top cross-sectional perspective view illustrating the attachment structure of the cam angle sensor shown in Fig . 1;

Fig . 6 is an exploded perspective view illustrating the attachment structure of the cam angle sensor shown in Fig . 1 ; Fig . 7 is a top perspective view illustrating a cam cap component according to a first embodiment; Fig. 8 is a bottom perspective view illustrating the cam cap component shown in Fig . 7 ;

Fig . 9A is a plan view illustrating the cam cap component shown in Fig . 7 ;

Fig . 9B is a bottom view illustrating the cam cap component shown in Fig. 7 ;

Fig . 9C is a front view illustrating the cam cap component shown in Fig . 7 ;

Fig . 9D is a right side view illustrating the cam cap component shown in Fig . 7 ; Fig . 10 is a top perspective view illustrating an attachment structure of cam angle sensors and OCVs according to a second embodiment ;

Fig . 11 is a top perspective view from a different angle illustrating the attachment structure of the cam angle sensors and the OCVs shown in Fig . 10 ;

Fig . 12 is a front view illustrating the attachment structure of the cam angle sensors and the OCVs shown in Fig . 10 ;

Fig . 13 is a left side view illustrating the attachment structure of the cam angle sensors and the OCVs shown in Fig . 10 ;

Fig . 14 is a plan view illustrating the attachment structure of the cam angle sensors and the OCVs shown in Fig . 10 ; Fig. 15 is a top perspective view illustrating a cam cap component according to a second embodiment;

Fig . 16 is a top perspective view from a different angle illustrating the cam cap component shown in Fig . 15 ;

Fig . 17 is a front view illustrating the cam cap component shown in Fig . 15 ;

Fig . 18 is a left side view illustrating the cam cap component shown in Fig . 15 ;

Fig . 19 is a plan view illustrating the cam cap component shown in Fig . 15 ; Fig . 20 is a bottom perspective view illustrating the cam cap component shown in Fig . 15 ;

Fig . 21 is a longitudinal cross-sectional view illustrating an OCV receiving portion according to the second embodiment in a state immediately before receiving an OCV; Fig. 22 is a longitudinal cross-sectional view illustrating the OCV receiving portion show in Fig . 21 after receiving the OCV;

Fig . 23A is a front view illustrating an annular gasket according to a second embodiment; Fig . 23B is a rear view illustrating the annular gasket shown in Fig . 23A;

Fig . 23C is a right side view illustrating the annular gasket shown in Fig. 23A;

Fig . 23D is a right side longitudinal cross-sectional view illustrating the annular gasket shown in Fig . 23A;

Fig. 23E is a plan view illustrating the annular gasket shown in Fig . 23A;

Fig . 23F is a perspective view illustrating the annular gasket shown in Fig. 23A; Fig . 24 is a top perspective view illustrating a cam cap component according to another embodiment ;

Fig . 25 is a top perspective view illustrating the cam cap component shown in Fig . 24 in use ;

Fig . 26 is a top perspective view illustrating the cam cap component shown in Fig . 24 in use; Fig . 27 is a top perspective view illustrating the cam cap component shown in Fig. 24 in use; and

Fig . 28 is a top perspective view illustrating a cam cap component according to another embodiment . Fig - 29 is a top cross-sectional perspective view illustrating the attachment structure of a cam angle sensor according to another embodiment .

BEST MODE FOR CARRYING OUT THE INVENTION

[First Embodiment]

Figs . 1 to 7 illustrate an attachment structure of a sensor for an internal combustion engine to which the present invention is applied. In this embodiment, the sensor for the internal combustion engine is a cam angle sensor 2. Fig . 1 is a top perspective view, Fig / 2 is a bottom perspective view, Fig . 3 is a front view, Fig . 4 is a right side view, Fig . 5 is a top cross-sectional perspective view, and Fig . 6 is an exploded perspective view .

The cam angle sensor 2 detects the rotational phase of a rotor 6 attached to an intake camshaft 4 by detecting passage of teeth βa formed on the rotor 6, thereby detecting the phase difference of an intake cam relative to the crankshaft of the engine . A hydraulically controlled variable valve actuation mechanism 400 is provided at an end of the intake camshaft 4. The variable valve actuation mechanism 400 has a timing sprocket connected to a sprocket of the crankshaft with a chain such that the timing sprocket is rotated at half the speed of the crankshaft . The variable valve actuation mechanism 400 is actuated by controlling the amount of hydraulic oil supplied by an oil control valve (hereinafter, referred to as OCV) , and rotates the timing sprocket of the mechanism 400 relative to the intake camshaft 4. Accordingly, the difference between the rotational phase of the intake camshaft 4 and that of the crankshaft is changed, so that the valve timing' of the intake valve is adjusted .

Since the variable valve actuation mechanism 400 is provided for the intake valve, the cam angle sensor 2 provided for the intake camshaft 4 will be discussed below . In a case where a similar variable valve actuation mechanism is provided for the exhaust valve, a cam angle sensor is also provided for the exhaust camshaft as in the description of the intake camshaft 4 below .

A cam cap component 8 is provided for supporting the cam angle sensor 2. The intake camshaft 4 is rotatably supported between the cam cap component 8 and a cam j ournal 10 provided in a cylinder head (including a cam carrier) 30.

Figs . 7 to 9 (D) show the cam cap component 8. Fig. 7 is a top perspective view, Fig . 8 is a bottom perspective view, Fig . 9A is a plan view , Fig . 9B is a bottom view, Fig . 9C is a front view, and Fig . 9D is a right side view .

The cam cap component 8 includes a base 12 that functions as a cam cap for supporting the intake camshaft 4 , and a receiving portion 13 for receiving the cam angle sensor 2.

The receiving portion 13 includes a sleeve 14 and a connecting portion 16 that connects the sleeve 14 to the base 12. The base 12 and the receiving portion 13 (the sleeve 14 and the connecting portion 16) are made of the same material as the cylinder head 30. In this embodiment , the base 12 and the receiving portion 13 are molded in one piece of an aluminum alloy. Alternatively, the base 12 and the receiving portion 13 may be formed separately and then integrated by attaching the receiving portion 13 to the base 12. The sleeve 14 has a columnar outer shape and has a receiving hole 14a in an eccentric position . The receiving hole 14a extends vertically through the entire sleeve 14 so that the sleeve 14 is formed as a cylinder . Further, a threaded hole 14c is formed vertically in an upper surface 14b of the sleeve 14. A body 2a of the cam angle sensor 2 is received by the receiving hole 14a . The cam angle sensor 2 has a stay 2b, in which a through hole 2c is formed. A screw 18 is inserted into the through hole 2c and screwed to the threaded hole 14c . As shown in Figs . 1 and 2 , the entire cam angle sensor 2 is attached to the sleeve 14 of the cam cap component 8 with the body 2a facing vertically downward. An 0-ring 3, which is an elastic rubber body, is provided on the outer circumference of the body 2a of the cam angle sensor 2. The 0-ring 3 functions as oil seal between the body 2a of the cam angle sensor 2 and the receiving hole 14a .

Since the cam cap component 8 , which functions as a cam cap, is fixed to the cam j ournal 10 at the base 12 with bolts 12a, the body 2a of the cam angle sensor 2 , which is attached to the cam cap component 8 , is located in the vicinity of the rotor 6, which is attached to and rotates integrally with the intake camshaft 4. The cam angle sensor 2 detects passage of the teeth 6a of the rotor 6, and outputs through a signal line 2d detection signals representing the passing timing to an electronic control circuit controlling the engine .

The upper surface 14b of the sleeve 14 of the cam cap component 8 is exposed from an opening 22 formed in a cylinder head cover 20. An annular gasket 24 , which is an elastic rubber body, is provided between the outer circumference of the sleeve 14 and the inner circumference of the opening 22. The annular gasket 24 seals the space between the sleeve 14 and the cylinder head cover 20. Therefore, even if the dimensional accuracy of the cylinder head cover 20 is not high, or even if the cylinder head cover 20 is deformed when being attached to the cylinder head 30 , displacement caused by such a low dimensional accuracy and deformation is absorbed by the annular gasket 24 , which is flexed accordingly. Therefore, sufficient oil sealing performance is maintained.

Further, even if the cylinder head cover 20 is deformed by the internal pressure or heat, the annular gasket 24 flexes to absorb displacement caused by the deformation . Sufficient oil sealing performance is therefore maintained. Also, even if the cylinder head cover 20 vibrates during the operation of the internal combustion engine, the vibration is absorbed by the annular gasket 24. Sufficient oil sealing performance is therefore maintained.

The receiving hole 14a and the threaded hole 14c of the sleeve 14 are completely exposed to the exterior of the cylinder head cover 20. Thus, the cam angle sensor 2 is fitted in the receiving hole 14a of the sleeve 14 and then fixed with the screw 18 after installing the intake camshaft 4 to the cam j ournal 10 with the cam cap component 8 , and attaching the cylinder head cover 20 to the cylinder head 30. Likewise, without removing the cylinder head cover 20 from the cylinder head 30 , the cam angle sensor 2 can be removed from the sleeve 14 by loosening the screw 18. In this manner, the cam angle sensor 2 can be inserted into and removed from the opening 22.

In the above described configuration, the rotor 6 corresponds to a component that is located between the cylinder head 30 and the cylinder head cover 20 while being covered with the cylinder head cover 20 , the gasket 24 corresponds to an oil seal member, the stay 2b and the screw 18 correspond to a fastening portion, and the threaded hole 14c corresponds to a coupler portion . The inner circumferential surface of the opening 22 corresponds to an opening forming portion of the cylinder head cover 20.

The first embodiment has the following advantages .

(i) The receiving portion 13 and the base 12 of the cam cap component 8 , which receives the cam angle sensor 2 , are molded firmly in one piece, and the base 12 is formed as a cam cap . Therefore, by fixing the base 12 of the cam cap component 8 to the cylinder head 30, or to the cam j ournal 10 of the cylinder head 30, the position of the receiving portion 13 on the cylinder head 30 is determined. Thus, the cam angle sensor 2 is not supported by the cylinder head cover 20 , but is firmly supported by the cylinder head 30 through the receiving portion 13 and the base 12.

Thus, the cam angle sensor 2 is firmly and accurately positioned relative to the intake camshaft 4 , which is supported by the cam journal 10 of the cylinder head 30 and the cam cap component 8. Accordingly, the position of the cam angle sensor 2 relative to the rotor 6 attached to the intake camshaft 4 is firmly and accurately determined.

Particularly, deformation and vibration of the cylinder head cover 20 , which are likely to occur since the cylinder head cover 20 is made of resin, are absorbed by the annular gasket 24 functioning as an oil seal member between the opening 22 of the cylinder head cover 20 and the sleeve 14. The deformation and vibration are therefore prevented from adversely influencing the positions of the sleeve 14 and the cam angle sensor 2.

Therefore, the cam angle sensor 2 is capable of accurately detecting the cam angle without being influenced by vibrations and deformation of the cylinder head cover 20.

Further, since the relative positions of the cam angle sensor 2 and the rotor 6 are firmly and accurately determined, the cam angle sensor 2 and the rotor 6 can be arranged sufficiently close to each other . Since the cam angle sensor 2 and the rotor 6 are arranged close to each other, the cam angle sensor 2 is capable of accurately detecting the teeth 6a .

(ii) The sleeve 14 of the receiving portion 13 has the receiving hole 14a at the distal portion into which the cam angle sensor 2 can be inserted and removed. Also, the sleeve 14 has the threaded hole 14c at the distal portion . The receiving hole 14a and the threaded hole 14c are exposed to the exterior from the opening 22. Thus , after the cylinder head cover 20 is attached to the cylinder head 30 , the cam angle sensor 2 can be efficiently attached to and removed from the receiving portion 13.

Since the upper surface of the annular gasket 24 is completely exposed to the exterior between the opening 22 of the cylinder head cover 20 and the sleeve 14 , the annular gasket 24 can be inserted into and removed from the outer side of the cylinder head cover 20. Therefore, after the cylinder head cover 20 is assembled, the annular gasket 24 can be easily installed or replaced without removing the cylinder head cover 20.

[Second Embodiment]

A cam cap component of this embodiment receives not only cam angle sensors but also OCVs that controls the supply of hydraulic oil to the variable valve actuation mechanisms . That is , as shown in Figs . 10 to 14 , a cam cap component 108 of this embodiment receives four function devices for an internal combustion engine, that is, two cam angle sensors 102 , 103 and two OCVs 104 , 105 for variable valve actuation mechanisms . The cam cap component 108 is provided on a cam j ournal 109 of a cylinder head 40.

Fig . 10 is a top perspective view illustrating a main portion, Fig . 11 is a top perspective view from a different angle after being pivoted about a vertical axis , Fig . 12 is a front view, Fig . 13 is a left side view, and Fig . 14 is a plan view. Although these drawings illustrate a state after a cylinder head cover 134 ( shown by broken lines in Figs . 12 to 14 ) has attached, the cylinder head cover 134 is depicted as transparent to show the interior of the cylinder head cover

134. Although individual portions of the cylinder head cover 134 that are necessary for describing the embodiment are separately shown by broken lines , these portions are formed integrally .

As show in the drawings, the cam angle sensors 102, 103 are arranged in the same manner as the first embodiment . That is , the cam angle sensors 102 , 103 are arranged to detect the passage of teeth 114a and 116a of an intake camshaft 110 and an exhaust camshaft 112 , respectively. The OCVs 104 , 105 actuate hydraulically controlled variable valve actuation mechanisms 401 , 402 provided at ends of the camshafts 110 , 112 to adjust the valve timings of intake valves and exhaust valves, respectively.

Figs . 15 to 20 show the cam cap component 108. The positions of the cam cap component 108 in Figs . 15 to 19 correspond to those in Figs . 10 to 14. That is, Fig. 15 is a top perspective view illustrating a main portion, Fig . 16 is a top perspective view from a different angle after being pivoted about a vertical axis, Fig. 17 is a front view, Fig . 18 is a left side view, and Fig. 19 is a plan view . Fig . 20 is a bottom perspective view.

The cam cap component 108 includes a base 120 that functions as cam caps for the intake camshaft 110 and the exhaust camshaft 112 , receiving portions 122 , 123 for receiving the cam angle sensor 102 , 103 , and receiving portions 124 , 125 for receiving OCVs .

The receiving portions 122 to 125 each have a sleeve 126, 127 , 128 , 129 having a receiving hole 126a, 127a, 128a, 129a . The receiving holes 126a, 127a, 128a, 129a each have a shape corresponding to the outer shape of the associated one of the cam angle sensors 102, 103 and the OCVs 104 , 105.

At the intake camshaft 110 , the cam angle sensor receiving portion 122 and the OCV receiving portion 124 are combined. That is , the receiving portions 122 and 124 are integrated with the base 120 by means of a sleeve 126 for the cam angle sensor of the receiving portion 122 , a sleeve 128 for the OCV of the receiving portion 124 , and a connecting portion 130 common to the sleeves 126, 128.

At the exhaust camshaft 112 , the cam angle sensor receiving portion 123 and the OCV receiving portion 125 are combined. That is, the receiving portions 123 and 125 are integrated with the base 120 by means of a sleeve 127 for the cam angle sensor of the receiving portion 123, a sleeve 129 for the OCV of the receiving portion 125, and a connecting portion 132 common to the sleeves 127 , 129.

The cam angle sensor receiving portions 122 , 123 have the same structure as described in the first embodiment . That is, the cam angle sensor 102 , 103 received by the receiving holes 126a, 127a are installed by inserting the screws 102c, 103c into the through holes in the stays 102b, 103b, and screwing the screws 102c, 103c into the threaded holes 126b, 127b formed in the upper surface of the sleeves 126, 127. This permits the rotational phases of the rotors 114 , 116 provided for the camshafts 110, 112 to be detected. Accordingly, the valve timings of the valves are detected.

The sleeves 128 , 129 of the OCV receiving portions 124 , 125 are cylindrical, and the receiving openings of the receiving holes 128a, 129a are slightly inclined upward. The receiving holes 128a, 129a are shaped to correspond to the outer shape of spool valve portions of the OCVs 104 , 105.

The cam cap component 108 includes oil passages that can communicate with the OCVs 104 , 105. Specifically, as shown by broken lines in Fig . 17 , in the cam cap component 108 , five oil passages 128b, 128c, 128d, 128e, 128f are provided to converge to the sleeve 128. Also, five oil passages 129b, 129c, 129d, 129e, 129f are formed to converge to the sleeve 129. The oil passages 128b to 128f are opened in the receiving hole 128a to correspond to five ports of the OCV 104. Likewise, the oil passages 129b to 129f are opened in the receiving hole 129a -to correspond to five ports of the OCV 105. The oil passages 128b and 128c permit hydraulic oil to flow between the OCV 104 and the variable valve actuation mechanism 401 , and the oil passages 129b and 129c permit hydraulic oil to flow between the OCV 105 and the variable valve actuation mechanism 402. The oil passage 128d is provided for supplying hydraulic oil to the OCV 104 , and the oil passage 129d is provided for supplying hydraulic oil to the OCV 105.

Among these oil passages, the phase retarding oil passages 128b, 129b each supply hydraulic oil to phase retarding hydraulic chambers defined in the variable valve actuation mechanisms 401 , 402 attached to ends of the camshafts 110 , 112 through phase retarding oil passages 110a, 112a ( see Figs . 10, 12 ) axially formed in the camshafts 110, 112. This configuration permits the rotational phases of the camshafts 110, 112 to be retarded.

The phase advancing oil passages 128c, 129c each supply hydraulic oil to phase advancing hydraulic chambers defined in the variable valve actuation mechanisms 401, 402 through phase advancing oil passages 110b, 112b ( see Figs . 10 , 12 ) axially formed in the camshafts 110, 112. This configuration permits the rotational phases of the camshafts 110 , 112 to be advanced.

The supplying oil passages 128d, 129d receive hydraulic pressure from a hydraulic oil supplying passage formed in the cylinder head 40 to supply hydraulic oil to the oil passages HOa, 112a, HOb, 112b through the OCVs 104 , 105. Thus , the supplying oil passages 128d, 129d extend to a center portion of the base 120 and merge into one passage that is connected to a hydraulic oil supplying connector 120a . The hydraulic oil supplying connector 120a connects the supplying oil passages 128d, 129d with the hydraulic oil supplying passage formed in the cylinder head 40 so that hydraulic oil is supplied to the supplying oil passages 128d, 129d.

Instead for forming the entire supplying oil passages 128d, 129d in the cam cap component 108 , the supplying oil passages 128d, 129d may be formed with pipes connected to the sleeves 128 , 129. Ends of these pipes may be directly connected to the hydraulic oil supplying passages formed in the cylinder head 40 , or to the base 120 to supply hydraulic oil from the hydraulic oil supplying connector 120a . When oil is supplied to one of the sets of the phase retarding oil passages 128b, 129b and the phase advancing oil passages 128c, 129c, the draining oil passages 128e, 128f, 129e, 129f drain oil from the other set to the cylinder head cover 134. Therefore, the draining oil passages 128e, 128f, 129e, 129f extend through the walls of the sleeves 128 , 129 and have openings on the outer circumference of the sleeves 128 , 129.

The cam cap component 108 including the base 120

(including the hydraulic oil supplying connector 120a) and the receiving portions 122 to 125 (the sleeves 126 to 129 and the connecting portions 130 , 132) is molded in one piece of the same material as that of the cylinder head 40, in this embodiment, an aluminum alloy. Alternatively, the base 120 and the receiving portions 122 to 125 may be formed separately and then integrated by attaching the receiving portions 122 to 125 to the base 120.

Fig. 21 is a longitudinal cross-sectional view illustrating the OCV receiving portion 124 in a state immediately before receiving the OCV 104. Fig . 22 is a longitudinal cross-sectional view illustrating the OCV receiving portion 124 after receiving the OCV 104. The other OCV receiving portion 125 has the same structure . An annular gasket 136, which functions as an oil seal member, is seals the space between the outer circumference of the sleeve 128 and the inner circumference of an opening 134a of the cylinder head cover 134 , thereby preventing hydraulic oil from leaking to the outside .

Figs . 23A to 23F illustrate the structure of the annular gasket 136. Fig. 23A is a front view, Fig. 23B is a rear view, Fig . 23C is a right side view, Fig . 23D is a right side longitudinal cross-sectional view, Fig . 23E is a plan view, and Fig . 23F is a perspective view . The annular gasket 136 includes a metal ring 136a having an L-shaped cross-section, and a lip portion 136b, which is an elastic rubber body. The lip portion 13βb covers the metal ring 13βa and extends in one axial direction to form a cylinder having a reducing diameter . As shown in Figs . 21 and 22 , when the annular gasket 136 is inserted in the opening 134a of the cylinder head cover 134 , the cylindrical portion of the metal ring 136a and the inner circumferential surface of the opening 134a compress the rubber elastic body. Accordingly, the annular gasket 136 is fitted in the opening 134a . At this time, the entire circumference of the distal end of the lip portion 136b closely contacts the outer circumference of the sleeve 128. The lip portion 136b therefore functions as oil seal between the sleeve 128 and the inner circumference of the opening

134a . Even if the dimensional accuracy of the cylinder head cover 134 is not high, or even if the cylinder head cover 134 is deformed when being attached to the cylinder head 40 , errors are absorbed by the lip portion 136b, or the elastic rubber body, which is flexed accordingly. Therefore, sufficient oil sealing performance is maintained. Further, even if the cylinder head cover 134 is deformed by the internal pressure or heat, the lip portion 136b is flexed to preserve the sufficient oil sealing performance .

As shown in Fig . 22 , a spool valve 104a of the OCV 104 is inserted into the receiving hole 128a of the sleeve 128 to install the OCV 104.

The sleeve 128 has a threaded portion 128g formed on the outer circumference of the distal portion and a threaded hole 128h . Likewise, the sleeve 129 has a threaded portion 129g and a threaded hole 129h . A screw 138 is inserted into a through hole formed in a flange 104b and screwed into the threaded hole 128h to prevent the installed OCV 104 from falling off . This firmly installs the OCV 104 in the sleeve 128. As for the sleeve 129, a screw 140 is screwed into the threaded hole 129h of the threaded portion 129g, so that the OCV 105 is fixed to a flange 105b .

Accordingly, the metal rings 136a of the annular gaskets 136 are held and pressed against the cylinder head cover 134 by the flanges 104b, 105b of the OCVs 104 , 105. This causes the annular gaskets 136 to closely contact the cylinder head cover 134.

The structure shown in Figs . 10 to 14 is assembled in the following manner . First, the two camshafts 110 , 112 are placed on the cam j ournal 109 provided in the cylinder head 40. Then, the cam cap component 108 is fastened with the bolts 144 such that the camshafts 110 , 112 are rotatably supported on the cam journal 109. The cylinder head cover 134 is fastened to a cylinder head 40 , for example, with bolts .

As shown in Fig. 21, the annular gasket 136 is placed between each opening 134a of the cylinder head cover 134 and the corresponding one of the sleeves 128 , 129. Thereafter, as shown in Fig . 22 , the spool valve portion of each of the OCVs 104 , 105 is inserted into the corresponding one of the receiving holes 128a, 129a of the sleeves 128 , 129.

Specifically, each spool valve portion is inserted into the opening 134a to which the annular gasket 136 is fitted. Then, the OCVs 104 , 105 are fastened to the sleeves 128 , 129 with the screws 138 , 140. Accordingly, the installment structure for the OCVs 104 , 105 is completed.

Further, as in the first embodiment, the cam angle sensors 102, 103 are inserted into the openings of the cylinder head cover 134 corresponding to the sleeves 126, 127 , thereby attaching the sleeves 126 , 127. Then, the sleeves 126, 127 are fastened with the screws 102c, 103c . The structure shown in Figs . 10 to 14 is thus completed.

In each of the cam angle sensors 102 , 103 , a portion of the cylinder head cover 134 exposed through an opening is connected to an electronic control unit with signal lines . This permits the cam angle to be detected. Further, electromagnetic solenoid portions 104c, 105c of the OCVs 104 , 105 exposed to the outside from the openings 134a of the cylinder head cover 134 are connected to the electronic control unit with signal lines . Accordingly, using hydraulic oil supplied to the supplying oil passages 128d, 129d from the hydraulic oil supply passages in the cylinder head 40 , the variable valve actuation mechanisms 401, 402 are actuated so that the valve timings of the intake valves and the exhaust valves are adj usted according to the operating state of the internal combustion engine .

When any of the thus installed function devices for the internal combustion engine (the cam angle sensors 102, 103 and the OCVs 104 , 105 ) malfunctions and that function device needs to be replaced, the screws 102c, 103c, 138 , 140 are removed to loosen the corresponding one of. the sleeves 126 to 129. Then, the device, or one of the cam angle sensors 102 , 103 and the OCVs 104 , 105 , is removed from the corresponding one of the receiving holes 126a to 129a . Then, a new device, or a replacement cam angle sensor or OCV, is fitted in the corresponding one of the receiving holes 126a to 129a . The device is fastened to the outer surface of the cylinder head cover 134 with a screw ( 102c, 103c, 138 , or 140) . In this manner, the replacement of the cam angle sensor 102 , 103 or the OCV 104 , 105 is completed.

In the second embodiment, the rotors 114 , 116 correspond to components that are located between the cylinder head 40 and the cylinder head cover 134 while being covered with the cylinder head cover 134. Further, in addition to the same gasket of the first embodiment, the annular gasket 136 corresponds to an oil seal member . The stays 102b, 103b, the screws 102c, 103c, the flanges 104b, 105b and the screws 138 , 140 correspond to fastening portions . The threaded holes 126b, 127b and the threaded holes 128h, 129h correspond to the coupler portions .

The second embodiment has the following advantages .

(i) The cam angle sensors 102 , 103 have the same advantages as the first embodiment . Also, since the base 120 is formed as one piece consisting of connected cam caps for the intake camshaft 110 and the exhaust camshaft 112, the cam angle sensors 102 , 103 are firmly fixed to the cylinder head 40. Further, since the OCV receiving portions 124 , 125 are integrated, the cam cap component 108 has increased weight and rigidity. The cam cap component 108 is therefore less likely to influenced by vibration and deformation of the cylinder head cover 134 , and the detection accuracy of the cam angle signal is further improved .

(ii) The OCVs 104 , 105, which supply hydraulic oil to the variable valve actuation mechanisms 401 , 402 , are also firmly supported on the cylinder head 40 as in the item (i) . The positions of the OCVs 104 , 105 relative to the cylinder head 40 are firmly and accurately determined. Therefore, the OCVs 104 , 105 are less likely to be influenced by vibration and deformation of the cylinder head cover 134. This prevents oil leakage at connecting portions between the hydraulic oil supplying connector 120a and the cylinder head 40 and connecting portions between the OCVs 104 , 105 and the sleeves 128 , 129. Further, since the oil passages 128b, 128c, 129b, 129c are formed without j oints from the sleeves 128 , 129 to the base 120 , the oiltightness is improved, and oil leakage is effectively prevented.

(iii) The OCVs 104 , 105 are attached to the distal portions of the sleeves 128 , 129 with the screws 138 , 140. The OCVs 104 , 105 and the screws 138 , 140 are exposed to the outside from the openings 134a of the cylinder head cover 134. Thus , after the cylinder head cover 134 is attached to the cylinder head 40 , the OCVs 104 , 105 can be efficiently attached and replaced.

Since the upper surface of the annular gasket 136 is completely exposed to the exterior between the openings 134a of cylinder head cover 134 and the sleeves 128 , 129, the annular gaskets 136 can be inserted into and removed from the outer side of the cylinder head cover 134. This structure permits the annular gaskets 136 to be easily installed or replaced without removing the cylinder head cover 134.

[Other Embodiments]

(a) In the second embodiment, the cam cap component is designed to receive the two cam angle sensors and the two OCVs for the intake camshaft and the exhaust camshaft . However, the cam cap component may be designed to receive only one set of a cam angle sensor and an OCV for either the intake camshaft or the exhaust camshaft .

Also, as shown in Figs . 24 to 27 , a cam cap component 208 for receiving only the OCVs 204 , 205 may be provided. The cam cap component 208 includes OCV receiving portions 224 , 225 and a base 220. The cam cap component 208 has the same structure as the cam cap component 108 of the second embodiment ( Figs . 15 to 20) except that the cam cap component 208 does not have the cam angle sensor receiving portions 122 , 123.

This configuration permits two camshafts 210 , 212 to be rotatably held between the cam cap component 208 and a cam j ournal 209 provided on the cylinder head 50 as shown in Fig . 25. After a cylinder head cover 234 is attached to the cylinder head 50 , the annular gaskets 136 (Fig . 23 ) are installed as shown in Fig . 21. Then, as shown in Fig . 26, the OCVs 204 , 205 are fixed to the receiving portions 224 , 225 with screws 238 , 240 to obtain an OCV attachment structure shown in Fig . 27. This structure has the advantages related to OCVs presented in the second embodiment .

(b) In the second embodiment and the embodiment of Figs . 24 to 27 , the orientation of the OCVs is perpendicular to the axial direction of the camshafts . ^' Other than this, a structure shown in Fig. 28 may be employed. In this embodiment, the axial direction of receiving holes 324a, 325a of OCV receiving portions 324 , 325 of a cam cap component 308 extends along the axial direction of camshafts, so that the attachment direction of OCVs are matched with the axial direction of the camshafts .

In the embodiment of Fig . 28 , the axial direction of the receiving holes is defined such that the distal ends of OCVs are inclined slightly downward. However, the cam cap component may be configured such that the OCVs are completely parallel to the camshafts .

In the embodiment of Fig . 2 and the embodiment of Figs . 24 to 27 , the axial direction of the receiving holes is defined such that the distal ends of OCVs are inclined slightly downward. However, the cam cap component may be configured such that the OCVs are completely parallel to a plane on which the camshafts are arranged.

(c) In the illustrated embodiments, the oil seal members (the annular gaskets 24 , 136) seal the space between openings of the cylinder head covers and the receiving portions as shown in Figs . 5, 22, and 26. Other than this, an oil seal member may be provided between a cam angle sensor protruding from the receiving portion and an opening of the cylinder head cover, or between an OCV protruding from the receiving portion and an opening of the cylinder head cover . For example, as shown in Fig . 29, a gasket 424 (an oil seal member) may be provided between the cam angle sensor 2 received by a receiving portion 413 and the opening 22. The gasket 424 contacts the outer circumference of the cam angle sensor 2 and the inner circumference of the opening 22.

(d) Each of the cam angle sensors in the illustrated embodiments faces a rotor and detects rotational phase . The present invention may be applied to a sensor for an internal combustion engine that contacts a component that is located between a cylinder head and a cylinder head cover, thereby detecting rotational phase . In this case, the same advantages as those of the illustrated embodiments are obtained.

Therefore, the present examples and embodiments are to be considered as illustrative and not restrictive and the invention is not to be limited to the details given herein, but may be modified within the scope and equivalence of the appended claims .

Claims

1. An attachment structure of a sensor for an internal combustion engine, wherein the engine has a component that is located between a cylinder head and a cylinder head cover of the engine while being covered by the cylinder head cover, the sensor contacting or facing the component, part of the sensor being exposed from an opening formed in the cylinder head, the attachment structure comprising : a receiving portion to which the sensor is detachably attached through the opening; a base integrally formed with the receiving portion, the base being fixed to the cylinder head to determine the position of the receiving portion relative to the cylinder head; an oil seal member for sealing a space between an opening forming portion, which is a portion of the cylinder head cover that forms the opening, and the receiving portion, or a space between the opening forming portion and the sensor; and a fastening portion that fastens the sensor to the receiving portion to maintain the attached state of the sensor to the receiving portion .

2. The attachment structure according to claim 1, wherein the sensor is a cam angle sensor for detecting a rotational phase of a camshaft of the engine, and wherein the component is a rotor provided on the camshaft, the rotor facing the cam angle sensor .

3. The attachment structure according to claim 2 , wherein the receiving portion includes a sleeve having a receiving hole to which the sensor is attached, wherein the base functions as a cam cap that supports the camshaft, and wherein the receiving portion and the base are molded in one piece .

4. The attachment structure according to claim 3, wherein the camshaft is one of an intake camshaft and an exhaust camshaft, and wherein the base functions as a cam cap for both of the intake camshaft and the exhaust camshaft .

5. The attachment structure according to any one of claims 1 to 4 , wherein the oil seal member is an annular rubber elastic body that contacts either an inner circumference of the opening and an outer circumference of the receiving portion, or an inner circumference of the opening and an outer circumference of the sensor .

6. The attachment structure according to claim 5, wherein the oil seal member is arranged such that the oil seal member is permitted to be inserted into and removed from the outer side of the cylinder head cover .

.

7. The attachment structure according to any one of claims 1 to 6, wherein the cylinder head cover is made of resin .

8. A cam cap component comprising a sleeve and a cam cap that are molded in one piece, wherein the sleeve has a receiving hole to which a function device for an internal combustion engine is attached, and wherein the cam camp supports a camshaft of the engine .

9. The cam cap component according to claim 8 , wherein the sleeve has a distal portion, at which the receiving hole is opened, and a coupler portion located in the vicinity of the distal portion, wherein the coupler portion couples the function device to the sleeve .

10. The cam cap component according to claim 8 or 9, wherein the engine has a hydraulically controlled variable valve actuation mechanism, and wherein the function device is an oil control valve that controls supply of hydraulic oil to the variable valve actuation mechanism.

11. The cam cap component according to claim 8 or 9 , wherein the function device is a cam angle sensor for detecting a rotational phase of the camshaft .

12. The cam cap component according to claim 8 or 9 , wherein the sleeve is one of a plurality of sleeves that are molded in one piece, and wherein the function device is one of a plurality of function devices each attached to one of the sleeves .

13. The cam cap component according to claim 12 , wherein the engine has a hydraulically controlled variable valve actuation mechanism, and wherein the function devices include an oil control valve that controls supply of hydraulic oil to the variable valve actuation mechanism and a cam angle sensor for detecting a rotational phase of the camshaft .

14. The cam cap component according to claim 10 or 13 , wherein the cam cap component includes an oil passage that is capable of communicating with the oil control valve .

15. The cam cap component according to claim 14 , wherein the oil passage permits hydraulic oil to flow between the oil control valve and the variable valve actuation mechanism.

16. The cam cap component according to claim 15 , further comprising an oil passage for supplying hydraulic oil to the oil control valve .