JP2630820B2 - Cam bearing lubrication system for DOHC engine - Google Patents

Abstract

PURPOSE:To deaerate communicating passages and oil passages by communicatedly opening the communicating passages to thrust regulating grooves formed on bearings provided on both sides of camshaft gears, and supplying lubricating oil to the bearings and the thrust regulating grooves. CONSTITUTION:Communicating passages 24, 25, 29-35 are communicatedly opened to thrust regulating grooves 17a, 18a, 21a, 23a formed at least on one side of bearings 17, 18, 21, 23 provided on both sides of gears 14 of camshafts 9a-9d. Lubricating oil supplied to oil passages 26, 27 are supplied to the bearings 17, 18, 21, 23 and the thrust regulating grooves 17a, 18a, 21a, 23a through the communicating passages 24, 25, 29-35. Hereby, lubrication of the bearings on both sides of the gears can be performed, and simultaneously deaeration of the communicating passages and the oil passages can be performed at the part of the thrust regulating grooves.

Description

Description: TECHNICAL FIELD The present invention relates to a cam bearing lubrication device for a DOHC engine in which two camshafts are arranged on the head of a cylinder head.

2. Description of the Related Art Conventionally, in a DOHC engine, two camshafts are meshed with gears provided on each shaft to drive gears and to restrict the movement of the camshaft in the axial direction. A structure in which a flange is provided, the flange is engaged with a thrust regulating groove formed in a bearing portion of a cylinder head, and lubricating oil is supplied to the engaging groove to absorb a thrust force by the oil pressure. It is known as seen in Japanese Patent Laid-Open No. 62-76205.

(Problems to be Solved by the Invention) However, regarding the lubrication of the cam bearings that support the camshafts on both sides in the DOHC engine, the camshaft is located between the pulley and the camshaft where the timing belt from the crankshaft is engaged. A drive gear, a valve cam, a flange, etc. are provided, and a cylinder head portion supporting the camshaft is provided with an intake / exhaust valve, a spark plug, and a head bolt with respect to the combustion chamber. It forms the bearing portion of the camshaft, and its structure is complicated. Further, in addition to the above structure, it is necessary to provide an oil passage for supplying the lubricating oil supplied from the cylinder block to each cam bearing, and exhaust air in the passage when supplying the lubricating oil when the engine is started. It is necessary to provide such a structure in an air bleeding structure, and it is desired that these structures can be easily configured.

In particular, it may be difficult to form the oil passage due to the shape of the gear in a portion where the bearing is disposed before and after the drive gear between the camshafts, and it is desired to form the bearing lubrication with a simple structure. On the other hand, in an engine such as a V-type engine in which a sliding direction of a cylinder shaft, that is, a piston is inclined, it is desired to form the engine into a structure in which oil leakage during engine stop is reduced.

In view of the above circumstances, the present invention provides a camshaft lubricating device for a DOHC engine in which a desired operation can be obtained with a simple structure for lubricating a cam bearing before and after a gear in an engine that drives gears between camshafts. The purpose is to do so.

(Means for Solving the Problems) In order to achieve the above object, a cam bearing lubricating device for a DOHC engine according to the present invention has a cam shaft provided with gears for driving between cam shafts, and both sides of the gears in the cam shaft direction. A thrust restriction groove is formed in at least one of the bearings, and an oil passage extending in the camshaft direction is formed below the bearing outside of the gear rotation trajectory. Is provided, and at least one of the bearings is configured such that the communication passage is opened to communicate with the thrust regulating groove.

Further, in an engine in which the cylinder shaft is inclined, a communication passage communicating with the oil passage is formed substantially vertically below the cam bearing, and the communication passage of the lower bearing is set longer than that of the upper inclination. The oil passage is formed outside the gear rotation locus only on the lower side of the slope.

(Operation) In the cam bearing lubricating device as described above, a communication path is provided from an oil passage formed in a lower portion of the bearing outside the rotation trajectory of the gear with respect to the bearing provided on both sides of the gear of the cam shaft,
The above-mentioned communication path is made to communicate and open to the thrust restriction groove formed in at least one of the bearings, and the lubricating oil supplied to the oil path is supplied to the bearing and the thrust restriction groove via the communication path,
In addition to lubricating the bearings before and after the gear, air is removed from the communication passage and the oil passage at the thrust regulating groove.

Further, in the case of gear driving between two camshafts arranged on the head of a cylinder head corresponding to an engine having an inclined cylinder shaft, a communication passage formed substantially vertically below each bearing is provided with a downwardly inclined communication passage. The communication path of the bearing on the side is set long so as to communicate with the oil path formed outside the gear rotation locus, and the lubricating oil supplied to the oil path is supplied to the bearing via the vertical communication path, and the oil path And lubrication of the bearings before and after the gear is performed, and oil is prevented from coming off by a substantially vertical communication path.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. First
The figure shows a schematic plan structure in which a cylinder head of a V-type DOHC engine is developed in a horizontal state, and FIG. 2 shows the front structure.

The V-type 6-cylinder engine 1 includes a right cylinder head 3 and a left cylinder head 4 on a cylinder block 2 at the lower center.
Are arranged obliquely, and a right bank R and a left bank L having three cylinders each of which slides a piston (not shown) at an angle to each other are formed. The cylinder row of the left bank L is arranged offset from the cylinder row of the right bank R forward (downward in FIG. 1).

On the upper surfaces of the cylinder heads 3 and 4, a plug hole 5 is formed substantially at the center corresponding to each cylinder, and each cylinder is provided with intake valve holes 6, 6, 2 provided with two intake valves.
Exhaust valve holes 7, 7 for mounting two exhaust valves are respectively opened, and bolt holes 8 for inserting head bolts for fastening the cylinder heads 3, 4 to the cylinder block 2 are arranged at equal intervals. ing.

A valve mechanism arranged above and below the right and left cylinder heads 3 and 4 for opening and closing the intake and exhaust valves includes two camshafts 9a to 9d for each cylinder head 3 and 4 (see FIG. 2). ) Is configured as a DOHC type. Each of the camshafts 9a to 9d is supported by fastening caps (not shown) to main cam bearings 11 disposed on both right and left sides of the plug hole 5, and has a front end or a rear end which will be described later. It is supported by bearings or thrust bearings.

At the front ends of a cam shaft 9a disposed on the right part of the right cylinder head 3 and a cam shaft 9c disposed on the right part of the left cylinder head 3, a cam pulley 12 protruding forward of the cylinder heads 3, 4 is provided. , 12 are installed, the timing belt 13 is engaged,
The camshafts 9a and 9c are driven in synchronization with the engine rotation.

Also, both cam shafts 9a, 9b or 9 of each cylinder head 3, 4
c, 9d are gears 14, 14 on the front end side of the cylinder heads 3, 4.
Are fixedly engaged with each other to gear-drive between the two camshafts. The cylinder heads 3 and 4 at positions corresponding to the gears 14 are provided with gear housing portions 3a and 4a formed to be larger than the head widths of other portions.

The right camshaft 9a of the right cylinder head 3
Is supported by front end bearings 16 and thrust bearings 17 provided on both front and rear sides of the gear housing 3a in the cam shaft direction. On the other hand, the front support of the left camshaft 9b in the right cylinder head 3 is performed by a thrust bearing 18 provided on the rear side of the gear housing 3a. Thrust bearing grooves 17a, 18a are formed in the thrust bearings 17, 18, and flanges 15 (fourth grooves) formed behind the gears 14 of the cam grooves 9a, 9b in the thrust restriction grooves 17a, 18a.
Figure) is fitted, and the movement in the axial direction is regulated. In addition,
In the cylinder head 3 at the rear end of the right camshaft 9a, an installation portion 3b of a distributor (not shown) is formed.

The front portion of the right cam shaft 9c in the left cylinder head 4 is supported by a front end bearing 20 provided on the front side of the gear housing portion 4a, and a thrust bearing 21 is provided at a rear end portion of the cam shaft. Similarly, the left cam shaft of the left cylinder head 4
The front support of 9d is a front end bearing provided on the front side of the gear housing 4a.
The thrust bearing 23 is provided at the rear end of the camshaft. Thrust bearing grooves 21a and 23a are formed in the thrust bearings 21 and 23, and flanges (not shown) formed at the rear ends of the camshafts 9c and 9d are fitted into the thrust regulating grooves 21a and 23a. , The movement in the axial direction is restricted.

An oil supply system for lubricating each cam bearing is formed corresponding to the above-described cylinder head structure. Outer and inner communication passages 24, 25 extending substantially vertically downward (see FIG. 2) are formed from the main cam bearings 11 in the right and left cylinder heads 3, 4, respectively, and lower end portions of the communication passages 24, 25 are formed. Are connected to outer and inner oil passages 26 and 27 extending in the cam shaft direction (see FIG. 5).

Cam shafts 9a, 9d located outside the right and left cylinder heads 3, 4
The outer oil passages 26, 26 formed are formed so as to extend from the rear ends of the cylinder heads 3, 4 to below the front end bearings 16, 22 at the front end, and extend outside the rotation trajectory of the gear 14. It is formed at a position distant from the center of the bearing. On the other hand, inner oil passages 27, 27 formed with respect to the camshafts 9b, 9c located inside the right and left cylinder heads 3, 4, respectively.
Are the gear housings 3a, 3a,
4a, it extends rearward and is formed at a position close to the center of the bearing so as to be inside the rotation locus of the gear 14. A processing hole 27a is formed in the front wall on the front extension of the inner oil passage 27, and the front and rear ends of the processing hole 27a and the oil passages 26, 27 are closed by plugs.

At the front end of the outer oil passage 26 in the right cylinder head 3, a communication passage between the front cam bearing 11 in front of the gear housing 3 a and the main cam bearing 11 for each rear cylinder is provided.
A front end communication passage 29 formed similarly to 24 is formed,
A communication passage 30 is formed in the thrust bearing 17 behind the gear housing 3a in a direction substantially orthogonal to the upper surface of the cylinder head. Further, at the front end of the inner oil passage 27 in the right cylinder head 3, a communication passage 31 is formed in a direction substantially orthogonal to the upper surface of the cylinder head with respect to the thrust bearing 18 behind the gear housing 3a. On the other hand, at the front end of the outer oil passage 26 in the left cylinder head 4, a communication passage 24 to the main cam bearing 11 for each rear cylinder is formed with respect to the front end bearing 22 in front of the gear housing 4a. The front end communication passage 32 is formed, and the front end bearing 20 of the inner bearing portion is further formed.
, A long front end communication passage 33 is formed. At the rear ends of the oil passages 27, 26 inside and outside the left cylinder head 4, communication passages 34, 35 are formed in the thrust bearings 21, 23 at the rear in a direction substantially orthogonal to the upper surface of the cylinder head. ing.

As shown in FIGS. 3 and 4, the structure of the communication passages 30, 31 for the thrust bearings 17, 18 (similarly for 21 and 23) is as follows.
The ends of the communication passages 30, 31 formed on the upper surface of the cylinder head from the oil passages 26, 27 correspond to the thrust bearing 1 of the cylinder head 3.
Opened near the thrust regulating grooves 17a, 18a on the upper surfaces of the 7, 7, and when the caps 37, 38 are fastened,
The communication passages 30, 31 are connected to the recesses 17b, 18b formed continuously with the thrust control grooves 17a ', 18a' of 38, so that the thrust control grooves 17a, 18a communicate with the communication passages 30, 31. Is configured. Further, the thrust regulating groove is a portion 17 on the cylinder head 3 side below the width of the flange 15 of the cam groove 9a.
a and 18a are inserted so as to restrict the movement in the axial direction with a narrow width, while the portions 17a 'and 18a' in the caps 37 and 38 are formed wider than the flange width so that the lubricating oil flows therethrough. In addition, air can be removed.

In the above structure, as shown in FIG. 2, the upper surfaces of the right and left cylinder heads 3 and 4 are formed so as to be inclined downward from the center to the outside, and the communication passages 24, 25, 29 and 3 are formed.
2 is the outer communication path 2 for the outer bearings 11, 16, and 22 on the inclined lower side.
4, 29, 32 are formed longer than the inner communication passage 25 for the inner bearing 11 on the inclined upper side. In other words,
As shown in FIG. 5, when the inner communication passage 25 is formed long,
It interferes with the plug hole 5, and the plug hole 5
The inner communication passage 25 is formed to be short from the viewpoint of securing the distance. An outer oil passage 26 formed outside the rotation locus of the gear 14 is also formed on the front side of the gear housing portion 3a (4a), and the outer oil passage 26 is formed on the front bearing 16 (22, 20) of the gear 14. A communication passage 29 (32, 33) is provided from the outer oil passage 26 to perform lubrication.

As shown in FIG. 6, an oil introduction passage 41 is formed diagonally upward from the oil introduction port 40 opened on the bottom surface of the cylinder head 3 (4). The upper end of the oil introduction passage 41 is open to an oil chamber 42 formed above the cylinder head. A supply passage 43 communicates with the inner oil passage 27 located immediately below the oil chamber 42 via a supply passage 43, and further has another supply passage 44 communicating with the outer oil passage 26 below the oil chamber 42.
Are formed.

Then, the lubricating oil pressure-fed from the cylinder block 2 flows into the oil chamber 42 from the inlet 40 through the introduction passage 41, and is supplied to the inner and outer oil passages 27 and 26, and the communication passages 24 and 2
It is supplied to each bearing 11,16-18,20-23 through 5,29-35,
The lubrication is performed. When the engine is stopped, the supply of the lubricating oil from the cylinder block 2 is stopped, and the lubricating oil and the like in the introduction passage 41 flow out to the cylinder block 2 side. Lubricating oil remains in the portions of the oil passages 26 and 27 to prevent the oil from escaping, so that the lubricating oil can be quickly supplied to the bearings when the engine is started next time.

In addition, in FIG. 1, reference numeral 45 denotes an intake manifold disposed between the cylinder heads 3 and 4 for supplying intake air to the cylinders of the cylinder heads 3 and 4.

According to the above-described embodiment, when the front end bearing 16 and the thrust bearing 17 are disposed before and after the gear 14, the oil passage 26
The communication passages 29 and 30 are opened to the bearing 16 and to the thrust regulating groove 17a, so that the bearing can be lubricated around the gear and air can be removed by using the thrust regulating groove with a simple structure. In the case where the cylinder axis is inclined as in the case of a V-type engine, the communication path is substantially vertical.
By forming one of the communication passages 24 and 25 so as to communicate with the oil passage 26 outside the gear rotation locus, the space for the plug hole 5 is secured, and the bearing in front of the gear is formed. Can be lubricated.

In the above-described embodiment, an example of a V-type six-cylinder engine has been described. However, a DOHC mechanism of a slant engine in which the cylinder axis is inclined in an in-line four-cylinder engine can be similarly configured. It is.

(Effects of the Invention) According to the present invention as described above, the communication passage is communicated and opened with the thrust regulating groove formed on at least one of the bearings provided on both sides of the gear of the camshaft, and the lubrication supplied to the oil passage is provided. By supplying the oil to the bearing and the thrust restriction groove via the communication path, the bearing can be lubricated before and after the gear, and the communication path and the oil path can be vented at the thrust restriction groove. Also, in an engine having a tilted cylinder shaft, the communication passage formed substantially vertically below each bearing is communicated with an oil passage formed outside the gear rotation locus by setting the communication passage of the bearing on the inclined lower side to be long. As a result, the oil passage can be ensured to lubricate the bearings before and after the gear, and the oil can be prevented from coming off by the substantially vertical communication passage.

[Brief description of the drawings]

FIG. 1 is a schematic plan view showing each cylinder head of a V-type DOHC engine according to an embodiment of the present invention in a horizontal state, FIG. 2 is a front view thereof, and FIG. 3 is a state in which a bearing cap is mounted. III-I in FIG.
FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. 3, which also shows the cam shaft at the same time along the line II, FIG. 5 is a cross-sectional view taken along line VV of FIG. 1, FIG. 6 is a sectional view taken along the line VI-VI. 1 ... Engine, 3,4 ... Cylinder head, 3a, 4a ... Gear storage, 5 ... Plug holes, 9a-9d ... Cam shaft, 11
…… Main cam bearing, 14 …… Gear, 15 …… Flange, 16,20,
22 …… Front end bearing, 17,18,21,23 …… Thrust bearing, 17a, 1
8a, 21a, 23a ... thrust regulating groove, 17b, 18b ... recess, 24,
25,29-35… Communication passage, 26,27… Oil passage, 40… Oil inlet, 41… Oil introduction passage, 42… Oil chamber,
43,44 …… Sending passage.

Claims (2)

(57) [Claims] In a DOHC engine, two camshafts are arranged side by side on the head of a cylinder head, and a gear that meshes with each camshaft is installed on each camshaft to drive a gear between the two camshafts. A bearing for supporting the camshaft on both sides of the gear in the camshaft direction is provided on the cylinder head, and a thrust regulating groove is formed in at least one of the bearings. An extending oil passage is formed, and a communication passage is provided from the oil passage to bearings on both sides of the gear, and in at least one of the bearings, the communication passage is opened to communicate with a thrust regulating groove.
Cam bearing lubrication device for DOHC engines. 2. A cylinder shaft is inclined, two cam shafts are arranged side by side on the head of the cylinder head corresponding to the cylinder shaft, and a gear meshing with each cam shaft is installed. In a DOHC engine in which gears are driven between both camshafts, bearings for supporting the camshafts are provided on a cylinder head, and communication passages are formed substantially vertically below the respective bearings. Is set to be longer than the communication path on the upper side of the slope, and an oil path communicating with the communication path is formed in the lower part of the bearing in the camshaft direction, and the oil path for the camshaft on the lower side of the inclination is formed on the outer side of the gear rotation path. A cam bearing lubrication device for a DOHC engine, characterized in that the lubrication device is formed as follows.