JP3380650B2 - Engine valve train lubrication structure - Google Patents

Description

Detailed Description of the Invention

The present invention relates to a valve train lubrication structure for an engine.

[0002]

2. Description of the Related Art In a reciprocating engine, an intake valve or an exhaust valve is driven to open and close at a predetermined timing in synchronization with the rotation of a crankshaft via a camshaft which is driven to rotate by a crankshaft of the engine. . Such a camshaft is rotatably supported via a plurality of bearings formed on the cylinder head, and in order to lubricate (the bearing surface of) these bearings, a lubricating oil is applied to each bearing. The supply passage is opened (see, for example, Japanese Utility Model Laid-Open No. 4-87308).

On the other hand, in recent engines, a variable valve timing mechanism is often provided in order to change the opening / closing timing of the intake valve or the exhaust valve according to the operating state of the engine. This variable valve timing mechanism is often operated hydraulically, and the valve opening / closing timing is changed according to the change of the supply state of the hydraulic oil, for example, supply and stop of supply (supply restriction).

[0004]

Since the variable valve timing mechanism as described above is provided on the camshaft, the hydraulic oil is supplied to the variable valve timing mechanism via the bearing portion of the camshaft. Become. That is, for example, the bearing portion and the variable valve timing mechanism are communicated with each other via the hollow portion formed in the cam shaft, and the working oil from the supply passage opened in the bearing portion passes through the hollow portion and the variable valve timing mechanism. Will be supplied to the mechanism.

A lubricating oil supply passage for lubricating the specific bearing portion is also opened in the bearing portion in which the hydraulic oil supply passage is opened, that is, the specific bearing portion. In this case, the lubricating oil from the lubricating oil supply passage may be supplied to the variable valve timing mechanism, and the variable valve timing mechanism may malfunction. In order to prevent such malfunctions, it is possible to set the working pressure of the variable valve timing mechanism to a sufficiently high value, but in order to completely prevent malfunctions, increase the working pressure more than necessary. This is unfavorable because it impairs fuel efficiency and imposes design restrictions on the variable valve timing mechanism.

Therefore, an object of the present invention is to prevent the variable valve timing mechanism from malfunctioning due to the lubricating oil supplied to the bearing portion without increasing the operating pressure of the variable valve timing mechanism more than necessary. To provide a valve valve diameter lubrication structure for an engine capable of reliably preventing the above.

In order to achieve the above object, the present invention (the invention according to claim 1) has the following configuration. That is, in the engine in which the hydraulically actuated variable valve timing mechanism is provided on the valve-driving cam shaft, an annular groove formed in one specific bearing part among a plurality of bearing parts that rotatably supports the cam shaft, A thrust restricting part for restricting axial movement of the cam shaft is formed by the flange part formed on the cam shaft and located in the annular groove. A first supply passage serving as a lubricating oil supply passage for the specific bearing portion on the one end face side in the cam shaft direction, sandwiching the one side thrust control face on the one end face side in the cam shaft direction of the flange part of the thrust limiter And a second supply passage serving as a supply passage of hydraulic oil to the variable valve timing mechanism is opened at the other end side in the cam shaft direction, and in the cam shaft, in series in the axial direction, A first hollow portion communicating with a bearing surface of a bearing portion other than the specific bearing portion and a second hollow portion communicating with the variable valve timing mechanism are formed, and the first hollow portion is the first hollow portion. While communicating with the supply passage,
The second hollow portion communicates with the second supply passage,
This is a structure that has a valve operating system lubrication structure for the engine. A preferred mode based on the above configuration is as described in claim 2 and the following claims.

[0008]

According to the first aspect of the present invention, the lubricating oil supplied from the first supply passage to the specific bearing portion has a sufficient pressure reduction due to the throttling action of the thrust regulating surface. Since only the two supply passages leak to the open side, it is possible to prevent the variable valve timing mechanism from malfunctioning due to the lubricating oil.

Lubricating oil can be supplied to the plurality of bearings from the first supply passage using the first hollow portion formed in the camshaft.

Further, by utilizing the hollow portion formed in the cam shaft, the second supply passage and the variable valve timing mechanism can be communicated with each other, and the second supply passage and the variable valve timing mechanism can be connected to each other by the cam shaft. There is no problem in supplying the hydraulic oil even if the positions are greatly separated in the direction. Of course,
Forming a hollow portion in the cam shaft is also preferable in terms of weight reduction of the cam shaft.

With the structure as described in claim 2, the hollow portion is formed to be long, which is preferable in terms of weight saving of the camshaft. Further, the hollow portion can be formed by, for example, machining from each end face side of the cam shaft, which is also preferable in terms of facilitating the formation of the hollow portion.

According to the third aspect of the present invention, since the two thrust regulating surfaces, that is, the two throttle portions are interposed between the first supply passage and the second supply passage, the variable valve timing is provided. The malfunction due to the lubricating oil of the mechanism can be prevented more reliably.

[0013]

With the structure as described in claim 4, the present invention can be applied to a device having a variable valve timing mechanism of a type that changes the rotational phases of the crank shaft and the cam shaft.

By adopting the structure as described in claim 5, the present invention can be applied to a device having a variable valve timing mechanism for each cam member. Further, it is possible to reduce the weight of the camshaft by forming the hollow portion while supplying or distributing the hydraulic oil to each variable valve timing mechanism by utilizing the hollow portion from one second supply passage.

According to the sixth and seventh aspects, the present invention can be applied to an engine having a more specific structure of the variable valve timing mechanism.

With the structure as described in claim 8, the lubricating oil is supplied from the base portion of the cylinder head to the protruding bearing portion where it is difficult to supply the lubricating oil to the first supply passage and the hollow portion in the camshaft. Can be used effectively.

With the structure as described in claim 9, a sufficient amount of lubricating oil leaked from both the protruding bearing portion and the specific bearing portion causes the two cam shafts to interlock with each other. This is preferable for supplying the rotation transmitting member with sufficient lubricating oil for the rotation transmitting member.

The structure as described in claim 10 is preferable in order to sufficiently lubricate the protruding bearing portion which receives a large force because the end portion side receives the rotation transmission from the crankshaft. . Further, the effect corresponding to claim 8 or claim 9 can be obtained.

[0020]

Embodiments of the present invention will be described below with reference to the accompanying drawings. In FIG. 1, reference numeral 1 denotes a cylinder head, and in the embodiment, a V-type 6-cylinder engine for one side bank is shown, and each cylinder has two intake valves and two exhaust valves. Has been done.

Reference numeral 2 is an intake valve cam shaft, and 3 is an exhaust valve cam shaft. In the cylinder head 1, first to fifth bearing portions 4A to 4E are formed as bearing portions for the intake valve camshaft 2, and similarly, first bearing portions for the exhaust valve camshaft 3 are provided. -Fifth total 5 bearing parts 5A-5E are formed.

The first bearing portions 4A and 5A at the left end in the figure are respectively formed as protruding bearing portions which are formed so as to project to the left side of the base portion of the cylinder head 1. Intake valve camshaft 3
Extends further to the left in the figure than the protruding bearing portion 4A, and the pulley 6 is fixed to this extended portion. The pulley 6 is linked to the crankshaft of the engine through a winding medium node such as a chain or a toothed belt (not shown).

Projecting bearing portions 4A, 5A as first bearing portions
And between the second bearing portions 4B and 5B adjacent to this,
A gear accommodating space 7 having a narrow width in the cam shaft direction is formed, and interlocking gears 8 and 9 are arranged in the gear accommodating space 7. The interlocking gears 8 and 9 are meshed with each other, the gear 8 is fixed to the intake valve camshaft 2, and the gear 9 is fixed to the exhaust valve camshaft 3. As a result, the rotation of the crankshaft is transmitted from the pulley 6 to the intake valve camshaft 2 and also to the exhaust valve camshaft 3 via the gears 8 and 9.

The intake valve camshaft 2 is provided with a total of six cam portions 11A to 11F, two for each cylinder, and hydraulically operated variable valve timing as will be described later for each of the cam portions 11A to 11F. Mechanisms 12A to 12F are configured.
Focusing on the intake valve camshaft 2, the lubricating oil supply to the bearings 4A to 4E and the hydraulic oil supply to the variable valve timing mechanisms 11A to 11F will be described with reference to FIG.

First, the second bearing portion 4B serves as a specific bearing portion, and like the other bearing portions, is substantially divided into upper and lower halves and fixed to the cylinder head 1 and the bolts. It is composed of the bearing cap 13. The reference numeral 13a indicates the inner surface of the bearing portion 4B, that is, the bearing surface serving as the rotary sliding surface of the cam shaft 2. This specific bearing portion 4B
A thrust restricting portion 20 for restricting the axial displacement of the cam shaft 2 is formed in the. The thrust restricting portion 20 includes an annular groove 21 formed in the second bearing portion 4 </ b> B so as to surround the entire circumference of the cam shaft 2, and a flange portion 22 formed integrally with the cam shaft 2 and located in the annular groove 21. Have and. The width of the flange portion 22 in the cam shaft direction is equal to that of the annular groove 21.
The width is slightly smaller than the width in the cam axis direction.

One end surface 22a of the flange portion 22 in the cam shaft direction
That is, when the left side surface of FIG. 2 abuts on the left side surface 21a of the annular groove 21, the cam shaft 2 is restricted from being displaced leftward with respect to the cylinder head 1.
a constitutes the first thrust control surface. Similarly, the cam shaft 2 is restricted from being displaced rightward with respect to the cylinder head 1 by contacting the other end surface 22b of the flange portion 22 in the cam axis direction, that is, the right side surface in FIG. 2 with the right side surface 21b of the annular groove 21. The two surfaces 21b and 22b form a second thrust restriction surface.

The diameter of the annular groove 21 is formed larger than the diameter of the flange portion 22, whereby the flange portion 22 is formed.
A predetermined gap 23 is formed all around. The overall shape of the predetermined gap 23 is an annular shape surrounding the flange portion 22.

In the cylinder head 1, two supply passages 31 and 32 are formed for the second bearing portion 4B as a specific bearing portion. The first supply passage 31 is
Of the bearing surface 13a of the second bearing portion 4B, the bearing surface 13a is opened to the left of the thrust regulating portion 20, and the second supply passage 32 is provided.
Is opened to the right of the thrust regulating portion 20.

Inside the camshaft 2, there are two hollow portions 3 of a first and a second, which are in series with each other with a thrust regulating portion 20 interposed therebetween.
3, 34 are formed. The first hollow portion 33 is located on the left side of the thrust regulating portion 20, and its right end portion is
Via the communication passage 35 extending in the diametrical direction of the cam shaft 2, the first
The supply passage 31 is opened in the opened bearing surface 13a. Further, as shown in FIG. 1, the left end portion of the first hollow portion 34 is opened to the bearing surface of the first bearing portion 4A via a communication passage 36 that extends obliquely in the radial direction of the cam shaft 2.

The second hollow portion 34 is opened at the right end of the camshaft 2, and the right end opening is liquid-tightly closed by a blind plug 37. In the embodiment, the second hollow portion 34 is formed by machining such as drilling. The left end portion of the second hollow portion 34 is opened to the bearing surface 13a where the second supply passage 32 is opened via a communication passage 38 extending in the diametrical direction of the cam shaft 2. Also, the second hollow portion 3
2 is in communication with variable valve timing mechanisms 12A to 12F, which will be described later, configured at the respective cam portions 11A to 11F at the positions of the respective cam portions 11A to 11F.

Third to fifth bearing portions 4 for the camshaft 2
As in the case of the first supply passage 31, the lubricating oil is directly supplied to C to 4E through the supply passage formed in the cylinder head 1. The lubricating oil is supplied to each bearing portion of the lubricating oil supply passage. The opening positions are indicated by reference numerals 31C to 31E.

A hollow portion 41 extending over the entire length is formed in the camshaft 3 for the exhaust valve, and each end of the hollow portion 41 is liquid-tightly closed by a blind plug 42 or 43. ing. The hollow portion 41 is opened to (the bearing surface of) the second bearing portion 5B via a communication passage 44 extending in the radial direction of the cam shaft 3. In addition, the hollow portion 41 is formed by the bearing portions 5A, 5C.
At positions 5E to 5E, each bearing portion 5 is provided via the branch communication passages 45A and 45C to 45E extending in the diametrical direction of the camshaft 3.
The bearing surfaces A, 5C to 5E are opened. Further, the thrust regulating portion 20B of the cam shaft 3 is formed in the second bearing portion 5B by the same structure as the intake valve cam shaft 2.

FIG. 3 shows the entire oil system path up to the camshaft 2 or 3. In this FIG.
The oil pumped up from the oil pan 52 by the pump 51 is supplied to the main oil passage 55 in the cylinder block from the passage 54 to which the filter 53 is connected.
A plurality of branch passages 5 branched from the main oil passage 55
It is supplied to a plurality of bearings for the crankshaft via 5a. Oil is supplied to each piston from a passage 56 extending from the main oil passage 55 via the branch passage 56a.

Main oil passage 5 in the cylinder block
A branch passage 57 branched from the middle of 5 is connected to a main oil passage 58 in the cylinder head 1, and an orifice 59 is connected to the branch passage 57. The main oil passage 58 in the cylinder head 1 has a plurality of branch passages, which are the first supply passages 31 and 31C.
˜31E and 44 are provided to lubricate the bearings of the camshafts 2 and 3.

The passage 5 upstream of the orifice 59
From 7, a further branch passage to which the control valve 60 is connected is branched, and this branch passage forms the second supply passage 32.
Thus, the hydraulic oil is supplied to the variable valve timing mechanism. The control valve 60 is of an electromagnetic type and opens when turned ON to supply hydraulic oil to the variable valve timing mechanism, and stops supply of hydraulic oil when turned OFF (drain).

In FIG. 3, reference numeral 61 is a safety valve for restricting the discharge pressure from the pump 51 to be above a predetermined value, and 62 is adjusted so that the pressure of oil supplied to the main oil passage 58 is within a predetermined pressure range. It is a pressure regulating valve. In addition, the orifice 5
By means of 9, the pressure of the oil supplied to the variable valve timing mechanism is sufficiently higher than the pressure of the lubricating oil supplied to the bearing portion. Of course, each of the main oil passages 55 and 58 is formed to be long in the crankshaft direction.

In the above structure, the specific bearing portion 4B of the intake valve camshaft 2 is lubricated by the lubricating oil supplied from the first supply passage 31. Further, the hydraulic oil is supplied to each of the variable valve timing mechanisms 12A to 12F from the second supply passage 32 to the communication passage 38 and the second hollow portion 3.
It is done through 4.

Here, in the specific bearing portion 4B, the lubricating oil from the first supply passage 31, that is, the lubricating oil, passes through the bearing surface 13a and the communication passage 3 for the variable valve timing mechanism.
It is possible that it will leak to 8. However, between the first supply passage 31 and the second supply passage (communication passage 38),
Since the two thrust regulating surfaces 21a, 22a and 21b, 22b having an extremely narrow width and having a large throttle action are located, the first supply passage 31 to the second supply passage 32 are located.
The pressure of the lubricating oil that has leaked to the side is sufficiently reduced, and it is possible to reliably prevent the variable valve timing mechanisms 12A to 12F from malfunctioning due to the lubricating oil from the first supply passage 31. To be done.

On the other hand, it is desired to supply a sufficient amount of lubricating oil to the gears 8 and 9 which interlock the two cam shafts 2 and 3, but in this embodiment, the gear 8 (9) is inserted. And two bearings 4A and 4B (5A and 5B) on both sides in the cam axis direction.
The lubricating oil leaking from the gear 8 (9) is sufficiently lubricated.

Furthermore, in the first bearing portion 4A for the intake valve,
Since there is a pulley 6 that is interlocked with the crankshaft, a considerably large bending force acts, and a sufficient amount of lubricating oil is required. In this case, since the first bearing portion 4A is a protruding bearing portion formed by protruding a part of the cylinder head 1 in the cam axis direction, the lubricating oil is directly supplied from the passage formed in the cylinder head 1. Would be difficult to supply. However, as in this embodiment, the first supply passage 3
By configuring a lubricating oil supply system path from 1 to the first bearing portion 4A via the first hollow portion 33 in the camshaft 2,
It becomes possible to supply a sufficient amount of lubricating oil to the first bearing portion 4A.

Description of Variable Valve Timing Mechanism (FIG.
(Fig. 11)

Next, an example of the variable valve timing mechanism provided for each cam portion in the embodiment shown in FIGS. 1 to 3 will be described with reference to FIGS. 4 to 11. In the embodiment, the variable valve timing mechanism is provided only for the intake valve cam shaft 2, and the variable valve timing mechanism is not provided for the exhaust valve cam shaft 3.
Further, since the variable valve timing mechanism in each cam portion has the same structure, the description will be made focusing on the cam portion 11B, that is, the variable valve timing mechanism 12B.

First, in FIG. 4, the cam portion 11B, that is, the variable valve timing mechanism 12B, includes a low-speed cam 72 integrated with the cam shaft main body 71 so as to always rotate integrally with the cam shaft main body 71, and a cam shaft main body. And a high-speed cam member 73 attached so as to be rotatable relative to each other. The shape settings of the low speed cam 72 and the high speed cam member 73 are as follows. That is, as shown in FIG. 5, the respective cams 72 and 73 have the same maximum lift amount, and in the state of FIG. 5 in which the position adjustment (phase matching) is performed to obtain the maximum lift amount, the maximum lift amount is reached. Up to and after passing through the maximum lift position, the high-speed cam member 73 is set to have a larger lift amount than the low-speed cam 72. Further, the valve opening timing is set so that the high speed cam member 73 is earlier than the low speed cam 72, and the valve closing timing is set so that the high speed cam member 73 is later than the low speed cam 72.

The high-speed cam member 73 has a long hole 74 formed on the side opposite to the maximum lift position by 180 degrees over a length of a predetermined range in the rotation direction. In addition, the camshaft body 71 has a locking pin 7 protruding into the elongated hole 74.
5 are integrated. The locking pin 75 is arranged so as to be located on the same axis as the straight line connecting the maximum lift position of the high speed cam member 73 and the rotation center. As a result, the high-speed cam member 73 can be swung from the state of FIG. 5 to the left and right within a range of a predetermined angle with respect to the cam shaft main body 71. It is regulated by contacting each inner end surface 74a or 74b of the long hole 74.

The camshaft body 71 has the second hollow portion 34.
A hole 76 extending over the entire length of the cam shaft body 71 in the diametrical direction is formed so as to be orthogonal to. The locking pin 75
Are pressed into the holes 76. The locking pin 75 extends in the direction opposite to the elongated hole 74 to a position slightly beyond the second hollow portion 34, and the locking pin 75 is provided in a portion of the hole 76 opposite to the elongated hole 74. The locking hole 76a does not have 75. The locking pin 75 is formed with a communication path 75a that always connects the second hollow portion 34 and the locking hole 76a.

On the other hand, a holding recess 77 having the same diameter as the hole 76 is formed on the inner end surface of the high speed cam member 73. A switching pin 78 and a pressing pin 79 are axially slidably fitted in the recess 77 sequentially from the side closer to the locking pin 75. The pressing pin 78 is inserted into the recess 77 through the pressing pin 79 by a spring 80 arranged in the recess 77.
It is urged to get out of.

The switching pin 78 has a locking hole 76a and a recess 77.
When and are aligned (matched with each other), they can be retracted into and retracted from the locking hole 76a (in any case, at least a part of the switching pin 78 is located in the recess 77). The switching pin 78 is projected into the locking hole 76a in FIG.
In this state, the high-speed cam member 73 is in a swinging restricted state in which the high-speed cam member 73 is integrally rotated with the cam shaft body 71. When the switching pin 78 has escaped from the locking hole 76a, the high-speed cam member 73 is in a swingable state in which it can swing with respect to the cam shaft body 71 within a predetermined angle range.

The switching of the switching pin 78 into and out of the locking hole 76a is performed by supplying or stopping the supply of the hydraulic oil to the locking hole 76a.
4 through the communication passage 75a. In this way, the locking hole 76a is configured as a hydraulic oil chamber of the variable valve timing mechanism 12B. In addition, in FIG. 4 and FIG.
Is a valve shaft of the intake valve, 82 is a tappet, and 83 is a spring for urging the intake valve in the valve closing direction. Also, the low speed cam 72
The connecting spring 84 interposed between the high speed cam member 73 and the high speed cam member 73 elastically connects the two members 72 and 73 to each other so that the high speed cam member 73 rotates together with the low speed cam 72. (The elastic deformation range of the connecting spring 84 is large enough to allow the locking pin 75 to swing within the elongated hole 74).

In the swinging regulation state in which the switching pin 78 is projected into the locking hole 76a, that is, in the state where the cam shaft main body 71 and the high speed cam member 73 rotate integrally, the valve opening characteristic of the intake valve is as shown in FIG. It becomes as shown by the solid line. Also, the switching pin 7
In the swingable state in which 8 has slipped out of the locking hole 76a, the valve opening characteristic of the intake valve is as shown by the broken line in FIG. Further, in the embodiment, the high speed valve opening characteristic shown by the solid line in FIG. 11 is set when the engine speed is higher than the predetermined speed, and the low speed valve opening characteristic shown by the broken line in FIG. 11 is set when the engine speed is lower than the predetermined speed. It

7 to 10 show the movement of the high speed cam member 73 when the low speed valve opening characteristic shown by the broken line in FIG. 11 is obtained. However, in FIGS. 7 to 10, for simplification,
The switching pin 78, the pressing pin 79, and the spring 80 are not shown. That is, as shown in FIGS. 7 and 8, the high-speed cam member 73 is hidden by the low-speed cam 72 and the valve opening characteristic is controlled by the low-speed cam 72 until the position where the maximum lift amount is obtained. By the biasing force of 83,
Initially, the locking pin 75 is brought into contact with the inner end surface 74a of the elongated hole 74, and is separated from the inner end surface 74a as it approaches the maximum lift amount position).

The state in which the maximum lift amount is obtained is shown in FIG.
At this time, the locking pin 75 is at the intermediate position of the long hole 74. After the position where the maximum lift amount is reached, as shown in FIG. 10, the high speed cam member 73 is hidden by the low speed cam 72, and the valve opening characteristic is dominated by the low speed cam 72 (the locking pin 75 is
(Abutting on the inner end surface 74b of the long hole 74).

Here, it is possible to change the high speed valve opening characteristic and the low speed valve opening characteristic only by using the high speed cam member 73 without the low speed cam 72. The valve opening characteristic (low speed valve opening characteristic) when the low speed cam 72 is removed and the high speed cam member 73 is allowed to swing with respect to the cam shaft body 71 is shown by a dashed line in FIG. 11.

Another embodiment (FIG. 12)

FIG. 12 shows another embodiment of the present invention, which corresponds to FIG. 1, in which the same components as those in the above-mentioned embodiment are designated by the same reference numerals and their duplicate description is omitted ( However, the gear 9 fixed to the exhaust valve cam shaft 3 is not shown). In this embodiment, the variable valve timing mechanism 1
2X is a rotary phase changing type attached to the end of the intake valve cam shaft 2. That is, as is known, a coupling portion coupled by a tilted spline is formed between the pulley 6 that is interlocked with the crankshaft and the cam shaft 2, and the coupling portion is relatively displaced in the cam axis direction. As a result, the rotational phase of the pulley 6, that is, the crankshaft and the camshaft 2 is changed.

The thrust restricting portion 20 of the camshaft 2 is formed in the second bearing portion 4B as in the case of FIG. The hydraulic oil supply system passage to the variable valve timing mechanism 12X is formed in the cylinder head 1 on the side of the variable valve timing mechanism 12X with respect to the thrust regulating portion 20. The second supply passage 32 (the bearing surface of the second bearing portion 4B). Opening), the second hollow portion 34 formed in the cam shaft 2, the variable valve timing mechanism 12X, and the pulley 6 via a passage 86 formed in a bolt 85 for attaching the pulley 6 to the cam shaft 2.

The lubricating oil is supplied to the second bearing portion 4B of the camshaft 2 through the first supply passage 31 opened to the second bearing portion 4B on the right side of the thrust regulating portion 20 in the drawing. Be seen. In this case, since the variable valve timing mechanism does not exist on the right side of the second bearing portion 4B, the first portion of the camshaft 2 is located on the right side of the thrust regulating portion 20.
The hollow portion 33 may be formed so that the lubricating oil is supplied from the first hollow portion 33 to the bearing portions 4C to 4E (the lubrication of the bearing portions 5B to 5E of the exhaust valve camshaft 3 in FIG. 1). Same method as oil supply).

The lubricating oil is supplied to the bearing portions 5B to 5E of the exhaust valve camshaft 3 in the same manner as in FIG. However, the supply of the lubricating oil to the first bearing portion 5A as the protruding bearing portion is performed by the supply passage 91 (formed in the cylinder head 1) that is open to the first bearing portion 5A side of the second bearing portion 5B with respect to the thrust regulating portion 20B. ) Is performed via the hollow portion 92 formed in the cam shaft 3.

First bearing portion 4 supporting the intake valve cam shaft 2
A, that is, the supply of the lubricating oil to the protruding bearing portion is branched from the first bearing portion 5A (the protruding bearing portion) of the exhaust valve cam shaft 3 (formed in the protruding portion of the cylinder head 1).
Is set up to be done through.

Another embodiment (FIGS. 13 to 20)

13 to 20 show another example of the variable valve timing mechanism constructed for each cam portion. The variable valve timing mechanism of this embodiment is the variable valve timing mechanism (12A to 12A) shown in FIGS.
Compared to E), it corresponds to one in which the low speed cam 72 is eliminated and the mechanism (78 to 80) for connecting and disconnecting the cam shaft main body 71 and the high speed cam member 73 is removed. A communication passage 95 extending in the radial direction is formed in the camshaft 2, and the communication passage 95 allows the hollow portion 33 in the camshaft 2 to be formed.
The (operating oil supply passage) is connected to the cam shaft body 71 and the cam member 73.
B (corresponding to the high speed cam member 73) is always in communication with the rotary sliding surface.

The operation of the cam member 73B is shown in FIGS. 13 to 16. At high revolutions, the high speed valve opening characteristic as shown by the solid line in FIG. 17 is obtained, and at low revolutions as shown by the chain line in FIG. A low speed valve opening characteristic can be obtained. The broken line in FIG. 17 is a reference valve opening characteristic obtained when the cam member 73B is integrally rotated with the cam shaft body 71. In addition, FIG.
16 indicates the cam member 7
3B shows a reference state when the 3B and the cam shaft body 71 are integrally rotated.

As shown in FIGS. 13 to 16, the cam member 7
3B uses the inertia caused by the rotation and the reaction force from the intake valve spring (reference numeral 83 in FIG. 4) to cause the camshaft body 71 to move.
One cycle passes while oscillating, that is, relative rotation with respect to. By such movement of the cam member 73B, as shown in FIG.
As shown by the solid line, the valve opening characteristic is changed according to the rotation speed.

It has been experimentally confirmed that the spring force of the intake valve, the cam shape, and the swing angle of the intake valve greatly affect the change of the valve opening characteristic depending on the rotational speed. The rotation resistance between the cam member 73B and the cam shaft body 71, that is, the resistance (shear resistance) due to the lubricating oil also has an influence. Therefore, the valve opening characteristic can be changed by making the resistance of the oil variable. 18 to 20 show an example of a variable means for varying the resistance due to oil. FIG. 18 is a type that changes the oil temperature, FIG. 19 is a type that changes the oil pressure, and FIG. Is a type that changes both the temperature and pressure of the oil. 18 to 20,
What is shown for VVT shows the oil supplied between the high speed cam member 73B and the cam shaft body 71, and what is shown for lubrication shows the oil supplied to the bearing portion.

In FIG. 18, the oil drawn up by the pump 51 from the oil pan 52 is filtered by the filter 53.
After passing through the two branch passages 101, 1 parallel to each other
It is branched to 02. The branch passage 101 has an orifice 1
03 is connected to lubricate the bearing portion.

A water-cooled oil cooler 104, for example, is connected to the branch passage 102 for a variable valve timing mechanism. The branch passage 102 has a cooler 104.
A bypass passage 105 for bypassing the valve is provided, and an electromagnetic flow rate adjusting valve 106 is connected to the bypass passage 105. By controlling the flow rate adjusting valve 106, the cooler 1
By changing the ratio of the amount of oil flowing through 04 and the amount of oil bypassing the cooler 104 (continuous variable type or multi-stage type change), the temperature of the oil supplied to the variable valve timing mechanism is desired. Is changed to (change of valve opening characteristics).

In the example of FIG. 19, the pump 51 and the filter 5
3. The oil passage after passing through the cooler 104 is branched into a branch passage 101 for the bearing portion and a branch passage 102 for the variable valve timing mechanism. An orifice 103 is connected to the passage 101, and a branch passage 101 downstream of the orifice 103 is connected to the branch passage 102 via a communication passage 107 and an electromagnetic control valve 108. The control valve 108 changes the amount ratio between the oil that has passed through the orifice 103 and the oil that does not pass through the orifice 103 (continuous variable type or multi-stage type change). The pressure of the supplied oil is changed (change in valve opening characteristics).

In the example of FIG. 20, the pump 51 and the filter 5
3. After passing through the cooler 104, the oil is branched into two branch passages 101 (for bearing lubrication) and 102 (for variable valve timing mechanism). An electromagnetic control valve 111 is connected to the branch passage 102, and the control valve 111 is connected to an oil passage between the filter 53 and the cooler 104 via a bypass passage 112 that bypasses the cooler 104. It is connected. An orifice 113 is connected to the bypass passage 112. Cooler 104 and control valve 1
The oil passage between the oil passage 11 and the passage 11 is a relief passage 11.
4 is connected to the oil pan 52 via this passage 114
An electromagnetic pressure regulating valve 115 is connected to.

By the control valve 111, the passage 11 is exclusively occupied.
By supplying the oil passing through 2 to the variable valve timing mechanism, the supplied oil has a low hydraulic pressure and a high temperature (small oil shearing force). By supplying the oil that passes through the cooler 104 exclusively to the variable valve timing mechanism by the control valve 11, the oil supplied is
High pressure and low temperature. Then, the pressure is adjusted by controlling the pressure regulating valve 115. In addition, the control valve 111
The ratio of the amount of oil from the passage 113 to the amount of oil from the cooler 104 side can be changed to a continuously variable type or a multi-stage type.

Although the embodiment has been described above, the present invention is not limited to this, and includes the following cases, for example.

(1) The variable valve timing mechanism may be provided on only one or both of the intake valve camshaft 2 and the exhaust valve camshaft 3.

(2) The second supply passage 32 for the variable valve timing mechanism is provided with the predetermined gap 2 in the thrust regulating portion 20.
On the other hand, the hollow portion in the cam shaft connected to the variable valve timing mechanism may be opened to the outer peripheral surface of the flange portion 22, that is, the predetermined gap 23.
In this case, the second supply passage 32 can always be communicated with the variable valve timing mechanism regardless of the rotational position of the cam shaft, which is preferable in terms of improving the hydraulic oil supply response.

(3) Between the first supply passage 31 for supplying the lubricating oil and the second supply passage for supplying the hydraulic oil of the variable valve timing mechanism, one of the two thrust regulating surfaces is thrust. It is also possible to set such that only the regulation surface is interposed.

(4) As the variable valve timing mechanism,
The structure is not limited to the one shown in the embodiment, and any suitable structure can be adopted as long as the hydraulic oil is supplied through the hydraulic oil supply passage formed in the cam shaft.

(5) The present invention is not limited to the V-type engine, but can be similarly applied to a serial engine. Further, the present invention is not limited to the so-called DOHC type engine in which the camshafts are separately provided for the intake valve and the exhaust valve, but also in the so-called SOHC type engine in which the camshafts for the intake valve and the exhaust valve are common. The same applies.

(6) The interlocking rotary member for interlocking the two camshafts 2 and 3 is not limited to a gear, but may be a sprocket (chain), a toothed pulley (toothed belt), or the like. Can be adopted. Further, as the rotation transmitting member for interlocking the cam shaft with the crank shaft, a sprocket (chain) may be used instead of the toothed pulley 6 (toothed belt). Of course, each of the camshafts 2 and 3 may be independently linked with the crankshaft without using one camshaft.

(7) A plurality of thrust regulating portions 20 may be provided for one cam shaft.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention, and is a top view of a cylinder head as seen from above.

FIG. 2 is a sectional view taken along line X2-X2 of FIG.

FIG. 3 is an overall system diagram of oil supply.

4 shows an example of a variable valve timing mechanism and is a cross-sectional view corresponding to line X4-X4 in FIG.

5 is a sectional view corresponding to line X5-X5 in FIG. 4.

6 is a view of the high speed cam member of FIG. 5 as viewed from above.

FIG. 7 is a diagram showing the movement of the high speed cam member of FIG. 4 in a state in which it can swing.

FIG. 8 is a diagram showing the movement of the high speed cam member of FIG. 4 in a state in which it can swing.

9 is a diagram showing the movement of the high-speed cam member of FIG. 4 in a swingable state.

FIG. 10 is a diagram showing a movement of the high speed cam member of FIG. 4 in a state in which the high speed cam member is swingable.

11 is a diagram showing a valve opening characteristic obtained by the variable valve timing mechanism shown in FIG.

FIG. 12 shows another embodiment of the present invention and is a view corresponding to FIG. 1.

FIG. 13 is a cross-sectional view of essential parts showing another example of the variable valve timing mechanism and its operation.

FIG. 14 is a cross-sectional view of essential parts showing the operation of the variable valve timing mechanism shown in FIG.

FIG. 15 is a cross-sectional view of an essential part showing the operation of the variable valve timing mechanism shown in FIG.

16 is a cross-sectional view of essential parts showing the operation of the variable valve timing mechanism shown in FIG.

17 is a diagram showing a valve opening characteristic obtained by the variable valve timing mechanism shown in FIG.

FIG. 18 is an oil system diagram for changing the valve opening characteristics of the variable valve timing mechanism shown in FIG.

FIG. 19 is an oil system diagram for changing the valve opening characteristics of the variable valve timing mechanism shown in FIG. 13.

20 is an oil system diagram for changing the valve opening characteristics of the variable valve timing mechanism shown in FIG.

[Explanation of sign]

1: Cylinder head 2: Cam shaft (for intake valve) 3: Cam shaft (for exhaust valve) 4A-4E: Bearing part 5A to 5E: Bearing part 6: Pulley (rotation transmission member that interlocks with the crankshaft) 8: Gear (rotation transmission member for interlocking with other cam shafts) 9: Gear (rotation transmitting member for interlocking with other cam shafts) 11A to 11F: cam part 12A to 12F, 12X: Variable valve timing mechanism 13: Bearing cap 14A to 14F: cam part 20: Thrust control department 21: annular groove 22: Flange part 21a, 22a: One thrust regulating surface 21b, 22b: the other thrust regulating surface 23: predetermined gap 31: First supply passage (for lubricating oil) 32: Second supply passage (for variable valve timing mechanism) 33: First hollow portion 34: Second hollow portion 71: Main body of cam shaft 72: Low speed cam 73: High speed cam member 73B: cam member 74: long hole 75: Locking pin 76a: Locking hole (hydraulic oil chamber) 78: Switching pin 79: Push pin 80: Spring 73B: cam member

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI F02F 1/24 F02F 1/24 R (72) Inventor Jun Miyashita 2-4-1 Niho, Minami-ku, Hiroshima City, Hiroshima Prefecture Mazda Industrial Stock In-house (56) References JP-A-6-173617 (JP, A) JP-A-62-150016 (JP, A) Actual Kaihei 4-87308 (JP, U) Actual Kaihei 3-123908 (JP, U) ) Shokai Sho 62-76205 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) F01L 13/00 301 F01L 1/04 F01M 1/06 F02F 1/24

Claims (10)

(57) [Claims] 1. An engine having a valve actuating camshaft provided with a hydraulically actuated variable valve timing mechanism, wherein one of a plurality of bearings rotatably supporting the camshaft.
An annular groove formed in one specific bearing portion and a flange portion formed in the cam shaft and located in the annular groove constitute a thrust restricting portion for restricting axial movement of the cam shaft, the bearing surface of each of the particular bearing part, by sandwiching the one-side thrust regulating surface which is a cam shaft direction end surface of the flange portion of the thrust control unit, the cam shaft direction end surface
A first supply passage serving as a lubricating oil supply passage for the specific bearing portion is opened on the side, and a second supply passage serving as a working oil supply passage for the variable valve timing mechanism is opened on the other end side in the cam shaft direction. , In the cam shaft, respectively in series in the axial direction, the specific shaft
The first hollow portion communicating with the bearing surface of the bearing portion other than the receiving portion
And a second medium communicating with the variable valve timing mechanism.
An empty space is formed, and the first hollow space communicates with the first supply passage.
And the second hollow portion communicates with the second supply passage.
The engine valve lubrication structure is characterized by 2. The first hollow portion according to claim 1, wherein the first hollow portion is open to one axial end surface side of the cam shaft.
Is formed so as to have an opening on the one end face side in the axial direction.
Min is applying a cover the second hollow part to the opening in the other axial end face side of the cam shaft
Is formed so as to have an opening on the other end surface side in the axial direction.
The valve operating system lubrication structure of the engine is characterized in that the portion is covered . 3. The axial end of the flange portion of the thrust regulating portion according to claim 1.
Of the one side thrust regulating surface which is the surface side and the flange portion.
The thrust control surface on the other side, which is the other side in the axial direction, is
In addition, the first supply passage and the second supply passage are the specified
A valve operating system lubricating structure for an engine, characterized in that the bearing surface of the bearing portion is opened . 4. The variable valve timing mechanism according to claim 1 , wherein the variable valve timing mechanism is in the axial direction of the cam shaft.
The rotation phase of the crankshaft and the camshaft provided at the end
A valve operating system lubrication structure for an engine, characterized in that it is configured to change . 5. The camshaft according to claim 1, wherein the camshaft includes a plurality of cam members corresponding to a plurality of cylinders.
And the variable valve timing mechanism is provided on the cam shaft.
A valve operating system lubrication structure for an engine, characterized in that it is configured for each cam member . 6. The variable valve timing mechanism according to claim 5 , wherein the variable valve timing mechanism rotates relative to the cam shaft body by a predetermined angle.
And a cam member attached to the current position.
The engine valve system lubrication structure. 7. The variable valve timing mechanism according to claim 6 , wherein the camshaft main body of the cam member is within the range of the predetermined angle.
Rotation permission state that allows relative rotation with respect to the relative rotation
To rotate the camshaft body and the cam member as a unit.
Further equipped with a pin member for switching to the rolling restriction state
The pin member supplies the hydraulic oil from the second supply passage.
The rotation permission state and the rotation regulation state according to the supply and the supply limitation
A valve operating system lubrication structure for an engine, characterized in that it is set to switch between and . 8. The cylinder head according to claim 1, wherein the bearing portion adjacent to the specific bearing portion is a cylinder head.
Projecting toward one end side in the axial direction of the cam shaft from the base part of
The projecting bearing portion is provided, and the lubricating oil is supplied to the projecting bearing portion by the first supply.
Set to take place from the passageway through the first hollow
The engine valve system lubrication structure is characterized in that 9. The cylinder head according to claim 1 , wherein the bearing portion adjacent to the specific bearing portion is a cylinder head.
Projecting toward one end side in the axial direction of the cam shaft from the base part of
A protruding bearing portion, a lubricating oil supply passage for the protruding bearing portion is formed , and the cam shaft and other parts are provided between the protruding bearing portion and the specific bearing portion.
A rotation transmission member for interlocking with the cam shaft is interposed, and the first supply passage is provided with the slide bearing of the specific bearing portion.
It is opened on the side closer to the rotation transmission member than the strike restricting portion.
The engine valve train lubrication structure is characterized by 10. The clan according to claim 8 or 9 , wherein the end of the cam shaft on the side of the protruding bearing is a clan.
If a passive side rotation transmission member that transmits rotation from the
The engine valve system lubrication structure is characterized in that