JPH08218836A - Lubrication structure for cam shaft bearing - Google Patents

Abstract

PURPOSE: To provide secure lubrication in a lubrication structure for a cam shaft bearing in which lubricating oil is supplied to between the cam shaft bearing and a journal part of a cam shaft, even in the cam shaft bearing in which a width of a lower part bearing is set to be relatively small to a width of an upper shaft bearing. CONSTITUTION: A cam shaft 11 is composed to be supported by a cam lower journal 13 and a cam upper journal 14, a journal width (t) of the cam lower journal 13 is set to be relatively small to a journal (T) of the cam upper journal 14. An oil supply hole 21 to supply lubricating oil in a diametric direction to a cam shaft 11 is formed to set lubricating oil supply quantity to the cam lower journal 13 smaller than lubricating oil supply quantity to the cam upper journal 14. An oil groove 24 is formed at an applicable position to the oil supply hole 21 of the upper journal 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lubricating structure for a camshaft bearing, and more particularly to a lubricating structure for a camshaft bearing which supplies lubricating oil between the camshaft bearing and a journal portion of the camshaft.

[0002]

2. Description of the Related Art Generally, an overhead camshaft (OH
The C) type engine valve drive mechanism has a structure in which a plurality of cam shaft bearings provided on a cylinder head support a cam shaft (hereinafter, referred to as a cam shaft). This cam shaft bearing includes a cam lower journal (lower bearing) formed on a cylinder head, and a cam upper journal (a lower shaft bearing) which is fixed to the cylinder head by mounting a cam shaft on the cam lower journal and bolting it from above. Upper bearing).

Lubricating oil is supplied to the portion where the camshaft is supported by the camshaft bearing, so that the smooth rotation of the camshaft is maintained. 2. Description of the Related Art Conventionally, as a lubricating structure for a cam shaft bearing that supplies lubricating oil to the cam shaft bearing, there is, for example, one disclosed in Toyota Technical Disclosure Collection (Issue No. 1216, issued September 29, 1986).

In the lubrication structure disclosed in the above-mentioned publication, a camshaft internal passage extending in the axial direction is formed in the center portion of the camshaft, and one end of the camshaft is journaled in the camshaft. An oil supply hole communicating with the passage and having the other end opened on the surface of the camshaft is formed. The lubricating oil sucked from the oil pan by the oil pump is configured to be introduced into the camshaft inner passage, so that the lubricating oil introduced into the camshaft inner passage passes through the oil supply hole and flows between the camshaft and the journal portion. The camshaft is supplied to the gap portion, so that the smooth rotation of the camshaft is maintained.

[0005]

In recent years, as the engine has become smaller and lighter, the size of the cylinder head in which the cam bearing is disposed has been reduced, and on the other hand, the number of valves has been increased to improve the engine performance. Increase (4 valves)
Is starting to take place.

As described above, with the reduction in size and weight of the engine and the increase in the number of valves, it is necessary to dispose the valve lifter hole formed in the cylinder head and the spot forming position of the head bolt and the cam bearing in close proximity to each other. In that, a valve lifter hole and a spot facing of a head bolt are formed by cutting a part of a cam lower journal.

This will be described with reference to FIGS. 20 and 21. FIG. 20 shows a camshaft bearing cam lower journal 1.
22 is an enlarged perspective view showing the vicinity of FIG. 21 and FIG. 21 is a plan view thereof. As shown in each drawing, the valve lifter hole 2 and the spot facing 3 of the head bolt are formed by cutting a part of the cam lower journal 1. Therefore, the substantial journal width t of the cam lower journal 1 is It becomes smaller than the originally required journal width T.

Since the cam upper journals are individually arranged on the upper part of the cam lower journal 1, there is no restriction like the cam lower journal 1, and therefore the width dimension is the journal width T. As described above, when the substantial journal width t of the cam lower journal 1 becomes smaller than the originally required journal width T, the lubricating oil is supplied from the oil supply hole formed in the cam shaft to the cam shaft and the cam shaft bearing. , The oil sealability of the cam lower journal 1 is low, so that the oil leakage from the cam lower journal 1 becomes large, and sufficient lubricating oil can be supplied to the cam upper journal (not shown). There was a problem that it could not be done.

The present invention has been made in view of the above points, and the width of the lower bearing is reduced by making the amount of lubricating oil supplied to the lower bearing smaller than the amount of lubricating oil supplied to the upper bearing. It is an object of the present invention to provide a lubrication structure for a cam shaft bearing, which can ensure reliable lubrication even in a cam shaft bearing whose width is set smaller than the width of the upper shaft bearing.

[0010]

[Means for Solving the Problems] The above-mentioned field problems can be solved by taking the following means. Claim 1
In the invention described above, the camshaft is configured to be supported by the upper and lower bearings, and the width of the lower bearing is set smaller than the width of the upper bearing. The lubricating oil supply amount to the lower bearing is smaller than the lubricating oil supply amount.

According to a second aspect of the present invention, in the lubricating structure for a cam shaft bearing according to the first aspect, an oil supply hole for supplying lubricating oil to the cam shaft in a radial direction is formed, and the upper portion is formed. An oil groove is formed at a position corresponding to the oil supply hole of the bearing.

According to a third aspect of the present invention, in the camshaft bearing lubricating structure according to the first aspect, an oil supply hole is formed in the camshaft to supply lubricating oil in a radial direction,
Further, a valve body is provided which is slidably disposed in the oil supply hole, and is configured to open and close the oil supply hole by slidingly displacing the oil, and the oil body is rotated with the rotation of the cam shaft. When a supply hole moves to a position facing the oil groove, a valve body moving mechanism that allows the valve body to move to a position that forms the lubricating oil supply path is provided. Lubrication structure.

Further, in the invention according to claim 4, in the lubricating structure for a cam shaft bearing according to claim 1, an oil introducing hole which is formed in the cam shaft in a radial direction and which introduces lubricating oil, A cam shaft inner passage which is communicated with the oil introduction hole and formed in the axial direction of the cam shaft, and formed in the radial direction and communicated with the cam shaft inner passage is introduced from the oil introduction hole. An oil supply hole for supplying lubricating oil to the upper and lower bearings is formed, and the lubricating oil is introduced into the oil introduction hole from the lubricating introduction means only when the oil supply hole faces the upper bearing. It is characterized by being configured as described above.

Further, in the invention according to claim 5, in the lubricating structure for the cam shaft bearing according to claim 4, two cam shaft inner passages are provided, and each of the cam shaft inner passages is provided with the oil introducing hole and the oil introducing hole. It is characterized in that the oil supply is provided and the oil introduction holes respectively arranged in the cam shaft inner passage communicate with the lubrication introduction means with a phase difference of 180 °.

[0015]

The above-mentioned means operate as follows. According to the invention described in claim 1, since the lubricating oil supply amount to the lower bearing is smaller than the lubricating oil supply amount to the upper bearing, the width of the lower bearing is larger than the width of the upper bearing. Even if the cam bearing is set to a small size, it is possible to reduce the leakage of lubricating oil in the lower bearing and supply a sufficient amount of lubricating oil to the upper bearing.

According to the second aspect of the invention, an oil groove is formed in the upper bearing, and the lubricating oil is supplied to the oil groove from the oil supply hole. It functions as a reservoir. Therefore, in order to reduce the leakage of lubricating oil in the lower bearing, even if the amount of lubricating oil supplied is made to correspond to the amount supplied to the lower bearing (that is, even if the amount of lubricating oil supplied is reduced), the upper bearing is lubricated. Since the oil is held in the oil groove, it is possible to always secure a sufficient amount of lubricating oil.

According to the third aspect of the present invention, the valve element slidably disposed in the oil supply hole is constantly urged to move in the radial direction by the centrifugal force generated by the rotation of the cam shaft. In the state where the oil supply hole faces the lower bearing as the camshaft rotates, no oil groove is formed in the lower bearing, so the valve body is pushed by the wall surface of the lower bearing to supply oil. Close the hole. Therefore, in the state where the oil supply hole faces the lower bearing, the amount of lubricating oil supplied from the oil supply hole is limited.

On the other hand, when the oil supply hole moves to a position facing the oil groove with the rotation of the cam shaft, the centrifugal force causes the valve element to enter the oil groove and open the oil supply hole. Therefore, when the oil supply hole faces the upper bearing, the amount of lubricating oil supplied from the oil supply hole is larger than when the oil supply hole faces the lower bearing. Therefore, the leakage of the lubricating oil in the lower bearing can be reduced, and the lubricating oil in the upper bearing can be reliably supplied.

According to the fourth aspect of the invention, the lubricating introduction means introduces the lubricating oil into the oil introduction hole only when the oil supply hole faces the upper bearing. The lubricating oil can be supplied only to the upper bearing by using a simple structure without using a valve body or the like by simply setting the timing at which the lubricating oil is introduced into the oil introduction hole.

Further, according to the invention described in claim 5, the oil introducing holes respectively provided in the two camshaft inner passages communicate with the lubricating introducing means with a phase difference of 180 °. As a result, one of the oil introduction holes always supplies the lubricating oil to the upper bearing during the rotation of the camshaft, so that the camshaft can be reliably lubricated.

[0021]

Next, an embodiment of the present invention will be described with reference to the drawings. First, before describing the lubrication structure of the cam shaft bearing according to the present invention, the bearing structure of the cam shaft (hereinafter referred to as the cam shaft) will be described with reference to FIGS. 5 and 6. FIG. 5 is an exploded perspective view showing the bearing 10, and FIG. 6 shows a cam shaft 11 supported by the bearing 10.

The bearing 10 includes a lower bearing 13 (hereinafter, referred to as a lower bearing) formed on a cylinder head 12 constituting an engine body.
A cam lower journal 13) and an upper bearing 14 (hereinafter referred to as a cam upper journal 14) fixed to the cylinder head 12 by mounting a cam shaft 11 on the cam lower journal 13 and bolting the cam shaft 11 from above.
That is) and. In the example shown in FIG.
A double overhead camshaft (DOHC) type engine using two camshafts 11 is shown as an example, so that each camshaft 11 is supported by seven bearings 10, respectively.

Further, as described above, the cylinder head 12 is made smaller and lighter and the number of valves is increased.
The valve lifter hole 15 and the counterbore 16 of the head bolt formed in 1 are formed by cutting a part of the cam lower journal 13 (see FIGS. 8 and 9). Therefore, as shown in FIG. 8, the substantial journal width t of the Camlore journal 13 is equal to the originally required journal width T.
Is smaller than.

However, since the cam upper journals 14 are individually arranged above the cam lower journals 13, there are restrictions such as the cam lower journals 13 due to the positions of the valve lifter holes 15 and the spot facings 16. Therefore, the width dimension of the cam upper journal 14 is the journal width T (shown in FIG. 5).

A pressing force is always applied to the camshaft 11 in the upward direction by a valve (not shown).
Since this pressing force is mainly received by the cam upper journal 14, a part of the cam lower journal 13 is scraped off by the valve lifter hole 15 and the counterbore 16 of the head bolt, and the substantial journal width t of the cam lower journal 13 is cut.
However, no problem arises from the point of bearing the camshaft 11. However, as described above, in terms of lubrication, the oil leakage from the cam lower journal 1 is increased.

Next, the structure of the camshaft 11 will be described with reference to FIG. The cam shaft 11 is formed with a plurality of cams 17 for driving the valve, and also formed with a plurality of journal portions 18 that are supported by the bearing 10. A camshaft internal passage 19 (camshaft internal passage) extending in the axial direction is formed in the center of the camshaft 11. Further, in the camshaft 11, one oil introduction hole 2 having a structure in which one end communicates with the camshaft passage 19 and the other end opens on the surface of the journal portion 18
0 and a plurality (five in the case of this embodiment) of oil supply holes 21 having the same structure as the oil introduction hole 20 are formed.

Of the plurality of bearings 10 described above, a journal portion in which an oil introduction hole 20 is formed (in particular, reference numeral 18a in the figure)
A bearing (shown by 10a in the figure) bearing an oil introduction passage 22 to which lubricating oil sucked from an oil pan by an oil pump is supplied (see FIG. 16). , The oil pump, the oil introduction passage 22 and the like cooperate to form a lubrication introduction means).
When the oil introducing passage 22 and the oil introducing hole 20 communicate with each other, the lubricating oil pressurized by the oil pump flows into the camshaft internal passage 19 through the oil introducing hole 20.

Further, as described above, the plurality of oil supply holes 21 are formed in the camshaft inner passage 19, and the lubricating oil flowing into the camshaft inner passage 19 passes through each oil supply hole 21 and the bearing 10. It is supplied between the journal portion 18 of the camshaft 11. As a result, the bearing 10 and the cam shaft 11 are lubricated smoothly.

Next, the lubricating structure of the cam bearing according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 4, the same components as those shown in FIGS. 5 and 6 are designated by the same reference numerals and the description thereof will be omitted. The lubricating structure according to the present embodiment is characterized in that an oil groove 24 is formed in the cam upper journal 14. The oil groove 24 has, for example, a width of 3 to 4 mm and a height of 2
The groove is about 3 mm, and is formed over the entire circumference of a position facing the cam upper journal 14 as shown in FIG.

The formation position of the camshaft 11 is
It is configured so as to correspond to the movement locus of the oil supply hole 21 formed in (1) (movement locus accompanying rotation of the camshaft 11). Therefore, when the oil supply hole 21 is rotationally displaced toward the cam upper journal 14 side with the rotation of the camshaft 11, the oil supply hole 21 is rotationally displaced while facing the oil groove 24, as shown in FIGS. 1 and 2. Will be done.

On the other hand, when the oil supply hole 21 is rotationally displaced toward the cam lower journal 13 as the cam shaft 11 rotates, as shown in FIGS. 3 and 4, the oil supply hole 21 is formed on the journal surface of the cam lower journal 13. It will be rotationally displaced while facing 25. Next, the operation of the lubricating structure having the above configuration will be described.

In this embodiment, the amount of lubricating oil supplied to the oil introduction hole 20 by the oil pump is set small. Specifically, the amount of lubricating oil supplied to the oil introduction hole 20 is set so that the oil supply hole 21 has a small journal width as the camshaft 11 rotates.
The supply amount is set so that oil does not leak when it faces the journal surface 25. Therefore, the oil introduction hole 2
By setting the supply amount of the lubricating oil supplied to 0 to a small value, oil leakage from the cam lower journal 13 will not occur.

Further, in this embodiment, as described above, the oil groove 24 is formed in the cam upper journal 14 so as to face the oil supply hole 21, and the lubricating oil is supplied to the oil groove 24 from the oil supply hole 21. It is configured to. Therefore, the oil groove 24 functions as a so-called oil sump, and the oil groove 24
It becomes possible to retain the lubricating oil inside.

Therefore, even if the supply amount of the lubricating oil is reduced in order to reduce the leakage of the lubricating oil in the cam lower journal 13 as described above, the lubricating oil is retained in the oil groove 24 in the cam upper journal 14. For,
The substantial amount of lubricating oil supplied to the cam upper journal 14 can be increased relative to the cam lower journal 13.

As described above, according to the lubricating structure of the present embodiment, the amount of lubricating oil supplied to the cam lower journal 13 can be made smaller than the amount of lubricating oil supplied to the cam upper journal 14. , The journal width t of the Kamuro journal 13 is the Kam upper journal 14
Even if the cam bearing 10 is set smaller than the journal width T of the above, it is possible to reduce the leakage of lubricating oil in the cam lower journal 13 and supply a sufficient amount of lubricating oil to the cam upper journal 000. Is possible.

A lubrication structure for a cam bearing according to the second embodiment of the present invention will be described with reference to FIGS. 7 to 11, the same components as those shown in FIGS. 5 and 6 are designated by the same reference numerals and the description thereof will be omitted. The lubrication structure according to the present embodiment forms the valve body 26 in the oil supply hole 21 so as to be slidable, and
It is characterized in that a convex rib 27 is formed on the cam lower journal 13.

The valve body 26 has, for example, a disc shape,
It is arranged in the oil supply hole 21. Further, the oil supply hole 21 according to the present embodiment is configured by the small diameter portion 21a and the large diameter portion 21b, and the diameter dimension of the disc-shaped valve body 26 is larger than the diameter dimension of the small diameter portion 21a, and It is set smaller than the size of the large diameter portion 21b. Therefore, the valve body 26 is configured to be slidable in the radial direction of the camshaft 11 within the large diameter portion 21b forming the oil supply hole 21.

Further, the valve body 26 closes the oil supply hole 21 by contacting the upper opening of the small diameter portion 21a (opening on the large diameter portion 21b side), and the valve body 26 moves from the upper opening of the small diameter portion 21a. The oil supply hole 21 is opened by being separated. Therefore, the flow of the lubricating oil flowing through the oil supply hole 21 is controlled by the valve body 26, and the valve body 26 closes the oil supply hole 21 so that the lubricating oil bearing 1
The supply of the lubricating oil to the bearing 10 is allowed by the valve body 26 opening the oil supply hole 21.

Further, as shown in FIG. 9, the rib 27 is formed over the entire circumference of the journal surface 25 of the cam lower journal 13. The formation position of the rib 27 is configured to correspond to the movement locus of the oil supply hole 21 that rotates with the rotation of the camshaft 11. Therefore, when the oil supply hole 21 rotates toward the cam lower journal 13 as the camshaft 11 rotates, the rib 27 faces the oil supply hole 21 (that is, the valve element 26).

The height of protrusion of the rib 27 from the journal surface 25 is set so that the valve body 26 can be pressed against the upper opening of the small diameter portion 21a while the rib 27 is engaged with the valve body 26. There is. Therefore, as the camshaft 11 rotates, the oil supply hole 21 rotates toward the cam lower journal 13 side, and the rib 27 presses the valve body 26 against the upper opening of the small diameter portion 21a, thereby causing the oil to flow as shown in FIG. The supply hole 21 is closed by the valve body 26.

On the other hand, the cam upper journal 14 has ribs 27 formed on the cam lower journal 13.
Is not formed. Therefore, even if the oil supply hole 21 rotates toward the cam upper journal 14 as the camshaft 11 rotates, the valve body 26 can be displaced within the large diameter portion 21b of the oil supply hole 21. Further, when the engine is driven, the camshaft 11 is rotating at a high speed, and therefore centrifugal force acts on the valve body 26 arranged inside the oil supply hole 21 formed in the radial direction of the camshaft 11. , Is always biased outward in the radial direction.

Therefore, when the oil supply hole 21 rotates toward the cam upper journal 14 side, the centrifugal force causes the valve body 2 to rotate.
6 is separated from the upper opening of the small diameter portion 21a.
As shown in FIG. 5, the valve body 26 is in a state where the oil supply hole 21 is opened. Next, the operation of the lubricating structure according to this embodiment will be described.

As described above, when the oil supply hole 21 rotates toward the cam lower journal 13 as the camshaft 11 rotates, the rib 27 presses the valve body 26 toward the upper opening of the small diameter portion 21a, and As shown in FIG. 10, the oil supply hole 21 is closed by the valve body 26. Therefore, the oil supply hole 2
In the state where 1 is facing the Camuro journal 13,
The supply of lubricating oil from the oil supply hole 21 is regulated.

When the oil supply hole 21 rotates toward the cam upper journal 14 as the camshaft 11 rotates, the valve body 26 is urged radially outward by the centrifugal force generated by the rotation of the camshaft 11. Therefore, as shown in FIG. 11, the valve body 26 opens the oil supply hole 21.
Therefore, the lubricating oil is supplied from the oil supply hole 21 toward the bearing 10.

As described above, according to the lubricating structure of the present embodiment, the amount of lubricating oil supplied to the cam lower journal 13 can be made smaller than the amount of lubricating oil supplied to the cam upper journal 14. Even with the cam bearing 10 in which the journal width t of the cam lower journal 13 is set smaller than the journal width T of the cam upper journal 14, the leakage of lubricating oil in the cam lower journal 13 can be reduced, and the cam upper journal 13 can be reduced. It becomes possible to supply a sufficient amount of lubricating oil to the journal 14.

Next, the lubricating structure of the cam bearing according to the third embodiment of the present invention will be described with reference to FIGS. 12 and 13. 12 and 13, the same components as those shown in FIGS. 5 to 11 are designated by the same reference numerals and the description thereof will be omitted. The lubricating structure according to this embodiment is
The valve body 28 is formed in the oil supply hole 21 so as to be slidable, and the oil supply hole 2 in the axial direction of the camshaft 11
It is characterized in that the diameter dimension W1 of No. 1 is set smaller than the width dimension W2 of the oil groove 24.

The valve element 28 has a pin-like shape and is arranged in the oil supply hole 21. The valve body 28 is composed of a spherical valve portion 28a and a cylindrical guide portion 28b.
The diameter of the spherical valve portion 28a that constitutes the valve body 28 is set to be larger than the diameter dimension W1 of the oil supply hole 21 and smaller than the width dimension W2 of the oil groove 24, and the cylindrical guide portion that constitutes the valve body 28 is formed. The diameter dimension of the portion 28b is set smaller than the diameter dimension W1 of the oil supply hole 21.

Therefore, in the valve body 28, the camshaft 11 is in the range where the cylindrical guide portion 28b faces the oil supply hole 21.
It is configured to be slidable in the oil supply hole 21 in the radial direction. The valve body 28 closes the oil supply hole 21 by the spherical valve portion 28 a contacting the journal surface side opening of the oil supply hole 21, and the spherical valve portion 28 a is separated from the journal surface side opening of the oil supply hole 21. By doing so, the oil supply hole 21 is opened.

Therefore, the flow of the lubricating oil flowing through the oil supply hole 21 is controlled by the valve body 28, and the valve body 28 closes the oil supply hole 21 to restrict the supply of the lubricating oil to the bearing 10 and the valve body. By opening the oil supply hole 21 by 28, the supply of lubricating oil to the bearing 10 is permitted. In addition, the cylindrical guide portion 28 that constitutes the valve body 28
b has a function of guiding the sliding of the valve body 28 in the oil supply hole 21 in the radial direction.

Further, as described above, the oil groove 24 is formed over the entire circumference of the journal surface 29 of the cam upper journal 14. The formation position of the oil groove 24 is configured so as to correspond to the movement trajectory of the oil supply hole 21 that rotates as the camshaft 11 rotates. Therefore, when the oil supply hole 21 rotates toward the cam upper journal 14 as the camshaft 11 rotates, the oil groove 24 faces the oil supply hole 21 (that is, the valve body 28).

Further, the depth of the oil groove 24 from the journal surface 29 is set so that the oil groove 24 faces the valve body 28.
The spherical valve portion 28a is set to have a depth dimension that allows it to enter the inside thereof. Therefore, when the oil supply hole 21 rotates toward the cam upper journal 14 side with the rotation of the camshaft 11 and the valve body 28 faces the oil supply hole 21, the valve body 28 is rotated by the centrifugal force generated by the rotation of the camshaft 11. After entering the oil groove 24, as shown in FIG.
The valve 1 is opened, and a distribution path through which lubricating oil can flow is formed.

On the other hand, the oil groove 24 formed in the cam upper journal 14 is formed in the cam lower journal 13.
Is not formed. Therefore, even if the oil supply hole 21 rotates toward the cam lower journal 13 as the cam shaft 11 rotates, the valve body 28 is pressed toward the oil supply hole 21 by the journal surface 25 of the cam lower journal 13. As shown by 13, the valve body 28 is in a state in which the oil supply hole 21 is closed.

Next, the operation of the lubricating structure according to this embodiment will be described. As described above, when the oil supply hole 21 rotates toward the cam lower journal 13 as the cam shaft 11 rotates, the journal surface 25 of the cam lower journal 13 causes the valve body 28 to move toward the journal surface side opening of the oil supply hole 21. Pressing and thus the oil supply hole 2 as shown in FIG.
1 is closed by the valve body 28. Therefore, when the oil supply hole 21 faces the cam lower journal 13, the supply of the lubricating oil from the oil supply hole 21 is restricted.

When the oil supply hole 21 rotates toward the cam upper journal 14 as the camshaft 11 rotates, the valve body 28 is urged radially outward by the centrifugal force generated by the rotation of the camshaft 11, Therefore, as shown in FIG. 12, the valve body 28 enters the oil groove 24 to open the oil supply hole 21. As described above, the diameter dimension W1 of the oil supply hole 21 with respect to the axial direction of the camshaft 11 is set smaller than the width dimension W2 of the oil groove 24.
When 8 enters into the oil groove 24, a flow path of lubricating oil is formed, so that the lubricating oil is supplied from the oil supply hole 21 toward the bearing 10.

As described above, the lubricating structure according to this embodiment can reduce the amount of lubricating oil supplied to the cam lower journal 13 relative to the amount of lubricating oil supplied to the cam upper journal 14. The journal width t of the cam lower journal 13 is the cam upper journal 14
Even if the cam bearing 10 is set smaller than the journal width T, the leakage of lubricating oil in the cam lower journal 13 can be reduced, and a sufficient amount of lubricating oil can be supplied to the cam upper journal 14. Is possible.

Next, the lubricating structure for the cam bearing according to the fourth embodiment of the present invention will be described with reference to FIGS. 14 and 15. 14 and 15, the same components as those shown in FIGS. 5 to 13 are designated by the same reference numerals and the description thereof will be omitted. The lubricating structure according to this embodiment is
Although it has substantially the same structure as the lubricating structure of the cam bearing according to the third embodiment described above, the depth dimension L of the oil groove 30 is larger than the diameter dimension of the spherical valve portion 28a of the valve body 28, and It is characterized in that the size is set smaller than the total length of the valve body 28 (size close to the total length of the valve body 28).

In the examples shown in FIGS. 14 and 15, the width dimension of the oil groove 30 is substantially the same as the diameter dimension of the oil supply hole 21, but the oil groove 30 is similar to the third embodiment described above. The width of the oil supply hole 21 may be set larger than the diameter of the oil supply hole 21. Also in the configuration of this embodiment, when the oil supply hole 21 rotates toward the cam upper journal 14 as the camshaft 11 rotates, the oil groove 30 faces the oil supply hole 21 (that is, the valve element 28). Therefore, when the valve body 28 faces the oil supply hole 21, the camshaft 1
The centrifugal force generated by the rotation of No. 1 causes the valve body 28 to move to the oil groove 3
0, and the oil supply hole 21 is opened as shown in FIG.

At this time, since the depth dimension L of the oil groove 30 is set to be larger than the diameter dimension of the spherical valve portion 28a of the valve body 28 and close to the entire length of the valve body 28 as described above, Compared to the third embodiment, the valve body 28 has a cam upper journal 1
4, the clearance formed between the cylindrical guide portion 28b and the oil supply hole 21 can be enlarged, and the lubricating oil is supplied from the oil supply hole 21 to the bearing 10 through this clearance portion. To be done.

As described above, the lubricating structure according to this embodiment can reduce the amount of lubricating oil supplied to the cam lower journal 13 relative to the amount of lubricating oil supplied to the cam upper journal 14. Therefore, the leakage of lubricating oil in the cam lower journal 13 can be reduced, and a sufficient amount of lubricating oil can be supplied to the cam upper journal 14.

Next, the lubricating structure for the cam bearing according to the fifth embodiment of the present invention will be described with reference to FIGS. 16 and 17. 16 and 17, the same components as those shown in FIGS. 5 to 15 are designated by the same reference numerals and the description thereof will be omitted. As described above with reference to FIG. 6, the camshaft 11 has a camshaft inner passage 19 that extends in the axial direction and serves as a passage for lubricating oil in the center thereof, and one end of the camshaft 11 communicates with the camshaft inner passage 19. An oil introduction hole 20 having a structure in which the other end is opened on the surface of the journal portion 18 and a plurality of oil supply holes 21 are formed.

Further, the bearing 10a (hereinafter referred to as the oil introduction bearing 10a) that supports the journal portion 18a in which the oil introduction hole 20 is formed has an oil introduction passage 22 to which the lubricating oil sucked by the oil pump is supplied. Although formed, in this embodiment, FIG.
As shown in FIG. 7 (A), an oil introduction groove 31 is formed over the entire circumference in the cam upper journal 14 which constitutes the oil introduction bearing 10a. The oil introducing groove 31 is formed only in the cam upper journal 14 which constitutes the introducing bearing 10a, and is not formed in the other cam upper journals 14 and the cam lower journals 13.

The oil introduction groove 31 is provided in the oil introduction bearing 10
The lubricating oil supplied by the oil pump is introduced into the oil introduction groove 31 through the oil introduction passage 22. The lubricating oil supplied by the oil pump is introduced into the oil introduction groove 31. It is configured.

On the other hand, the arrangement positional relationship between the oil introduction holes 20 formed in the camshaft 11 and the plurality of oil supply holes 21 is such that all the oil supply holes 21 introduce oil in the axial direction of the camshaft 11. It is set to face the hole 20. That is, assuming that the position of the oil introducing hole 20 is now at a position inclined by an angle θ in the counterclockwise direction from the vertically upper position as shown in FIG.
As shown in (B), it is arranged so as to be at a position inclined by an angle θ counterclockwise from the vertically upper position.

Next, the operation of the lubricating structure having the above-mentioned structure according to this embodiment will be described. In this embodiment, as described above, the cam upper journal 14 constituting the oil introducing bearing 10a is formed with the oil introducing groove 31 over the entire circumference, and the lubricating oil is supplied from the oil pump to the oil introducing groove 31. ing. Therefore, as the cam shaft 11 rotates, the oil introduction hole 20 is
16A, the oil introducing hole 20 communicates with the oil introducing groove 31, and the lubricating oil in the oil introducing groove 31 flows into the oil introducing hole 20.

Further, since the oil introduction hole 20 is constructed to communicate with the oil supply hole 21 through the camshaft internal passage 19, the lubricating oil flowing from the oil introduction groove 31 into the oil introduction hole 20 is supplied to the camshaft. The oil flows in the inner passage 19 and is supplied to the bearing 10 through a plurality of oil supply holes 21 formed.

At this time, as described above, the oil introduction groove 31 is provided in the cam upper journal 1 constituting the oil introduction bearing 10a.
Since it is formed only in No. 4, the introduction of the lubricating oil from the oil introduction groove 31 to the oil introduction hole 20 is performed only in the rotation range where the oil introduction hole 20 faces the cam upper journal 14.

On the other hand, when the oil introducing hole 20 rotationally moves toward the cam lower journal 13 as the cam shaft 11 rotates, an oil introducing groove 31 is formed in the cam lower journal 13 as shown in FIG. 17 (A). Therefore, the introduction of the lubricating oil to the oil introduction hole 20 is stopped in the rotation range where the oil introduction hole 20 faces the cam lower journal 13.

Further, as described above, all the oil supply holes 21 are arranged so as to face the oil introduction hole 20 and the cam shaft 11 in the axial direction, so that the lubricating oil is not supplied to the bearing 10. Lubrication for the bearing 10 is performed only when the oil supply hole 21 faces the cam upper journal 14, and when the oil supply hole 21 faces the cam lower journal 13 as shown in FIG. No oil is supplied.

Therefore, according to the lubricating structure of this embodiment, the amount of lubricating oil supplied to the cam lower journal 13 can be reduced relative to the amount of lubricating oil supplied to the cam upper journal 14. Thirteen
Of the cam bearing 10 is set to have a smaller journal width t than the journal width T of the cam upper journal 14.
Even if it is, the leakage of lubricating oil in the cam lower journal 13 can be reduced, and the cam upper journal 14
Therefore, it becomes possible to supply a sufficient amount of lubricating oil.

Further, in the lubrication structure of the present embodiment, the oil introduction groove 31 can be set to the cam upper simply by appropriately setting the timing when the lubrication oil is introduced into the oil introduction hole 20 from the lubrication introduction means such as an oil pump. By forming only on the journal 14, it is possible to supply the lubricating oil only to the cam upper journal 14, and it is not necessary to use a valve body or the like as in the above-mentioned embodiment, and the cam can be surely structured with a simple structure. It becomes possible to supply the lubricating oil only to the upper journal 14.

Next, the lubricating structure for the cam bearing according to the sixth embodiment of the present invention will be described with reference to FIGS. 18 and 19. 18 and 19, the same components as those shown in FIGS. 5 to 17 are designated by the same reference numerals and the description thereof will be omitted. As described above, according to the fifth embodiment, it is possible to supply the lubricating oil only to the cam upper journal 14, but the lubricating oil is supplied to the cam upper journal 14.
The oil introduction hole 20 within one rotation (360 °) of 1 is limited to the rotation range of 180 ° facing the cam upper journal 14.

That is, in the structure of the fifth embodiment, the lubricating oil is supplied to the cam upper journal 14 only once in a range of 180 ° while the camshaft 11 makes one revolution.
Lubrication oil supply efficiency was poor. Therefore, the present embodiment is characterized in that the lubricating oil is always supplied to the cam upper journal 14. The specific configuration will be described below.

In the lubricating structure according to this embodiment, the first and second camshaft internal passages 32, 3 are provided in the camshaft 11.
3 is provided, and the first camshaft passage 32 is provided.
The first oil introduction hole 34 and the plurality of first oil supply holes 35
In addition, a second oil introduction hole 36 and a plurality of second oil supply holes 37 are formed in the second camshaft passage 33.

A partition wall 38 is formed between the first camshaft inner passage 32 and the second camshaft inner passage 33, and the first camshaft inner passage 32 and the second camshaft inner passage 33 are formed. Lubricating oil cannot come and go between and. Further, the first oil introduction hole 34 and the plurality of first oil supply holes 35 are communicated with each other through the first camshaft inner passage 32, and all the first oil supply holes 35 are connected to the camshaft 11. It is set to face the first oil introduction hole 34 in the axial direction of.

Similarly, the second oil introducing hole 36 and the plurality of second oil introducing holes 36
Of the oil supply holes 37 are communicated with each other via the second camshaft internal passage 33, and all the second oil supply holes 37 are connected to the second oil introduction holes 36 in the axial direction of the camshaft 11. It is set to face each other. Furthermore, the first oil introduction hole 34 and the second oil introduction hole 36 are not
Are formed so as to face each other about the central axis of the, that is, they are separated by 180 °.

Also in this embodiment, the oil introduction groove 31 is provided in the cam upper journal 1 constituting the introduction bearing 10a.
No. 4 is formed, and the other cam upper journal 14 and the cam lower journal 13 are not formed. Next, the operation of the lubricating structure having the above-described configuration according to this embodiment will be described.

In this embodiment, as described above, the first oil introduction hole 34 and the second oil introduction hole 36 are formed so as to face each other around the central axis of the camshaft 11. Therefore, in the state where the first oil introduction hole 34 faces the oil introduction groove 31 and the lubricating oil is introduced, the lubricating oil is supplied from the first oil supply hole 35 toward the cam upper journal 14. Further, in the state where the second oil introduction hole 36 faces the oil introduction groove 31 and the lubricating oil is introduced, the lubricating oil is supplied from the second oil supply hole 37 toward the cam upper journal 14.

Here, the state immediately before the camshaft 11 is rotated clockwise from the state shown in FIG. 18 and the first oil introducing hole 34 is separated from the cam upper journal 14 is shown in FIG.
9 shows. In the state shown in FIG. 19, the first oil introduction hole 34 still faces the oil introduction groove 31, and the lubricating oil is being supplied from the first oil supply hole 35 to the cam upper journal 14. Further, the second oil introduction hole 36 faces the cam lower journal 13 in this state, so that the lubricating oil is not supplied from the second oil supply hole 37 to the cam lower journal 13.

When the camshaft 11 is further rotated clockwise from the state shown in FIG. 19, the first oil introducing hole 34 is separated from the oil introducing groove 31 and the cam lower journal 1 is moved.
It will be in a state of facing 3. By entering this state,
The first oil supply hole 35 is also in a state of facing the cam lower journal 13, but from the oil introduction groove 31 to the first oil introduction hole 34.
Since the introduction of the lubricating oil to the is stopped, the lubricating oil is not supplied from the first oil supply hole 35 to the cam lower journal 13.

On the other hand, as the camshaft 11 rotates clockwise as described above, the first oil introduction hole 34
Instead of this, the second oil introduction hole 36 is in communication with the oil introduction groove 31. Therefore, the lubricating oil in the oil introducing groove 31 is supplied from the second oil introducing hole 36 to the second camshaft passage 33.
Therefore, the lubricating oil is supplied from the second oil supply hole 37 toward the cam upper journal 14.

As described above, the lubricating structure according to this embodiment can reduce the amount of lubricating oil supplied to the cam lower journal 13 relative to the amount of lubricating oil supplied to the cam upper journal 14. It is possible to reduce the leakage of the lubricating oil in the Cam lower journal 13,
In addition, it becomes possible to supply a sufficient amount of lubricating oil to the cam upper journal 14. Further, in the lubrication structure according to the present embodiment, the first oil introduction hole 34 and the second oil introduction hole provided in the first and second camshaft passages 32 and 33 provided in the 112 camshafts, respectively. Hole 36 and 180
Since it is configured to communicate with the oil introduction groove 31 with a phase difference, either one of the first or second oil introduction holes 34, 36 always supplies lubricating oil to the cam upper journal 14. As a result, the camshaft 11 can be lubricated more reliably.

In the fifth and sixth embodiments described above, the oil introduction holes 20, 34, 35 and the plurality of oil supply holes 21,
The arrangement positional relationship with 36, 37 is that all the oil supply holes 21,
Although an example in which 36 and 37 are arranged to face the oil introduction holes 20, 34 and 35 in the axial direction of the camshaft 11 has been shown, as shown in FIG.
Reference numerals 9, 32, and 33 are formed to extend for a long time. Therefore, oil supply holes 21, 36, and 37 formed at positions close to the oil introduction holes 20, 34, and 35, and oil formed at positions separated from each other. A time delay occurs in the oil supply between the supply holes 21, 36 and 37.

Therefore, in order to correct this time delay,
The positions where the oil supply holes 21, 36, 37 are formed are changed to the oil introduction holes 2
It may be arranged such that the positions 0, 34, and 35 are shifted (that is, the θ value in FIG. 16A is different from the θ value in FIG. 16B).

[0084]

As described above, according to the present invention, the following various effects can be realized. According to the invention described in claim 1, since the lubricating oil supply amount to the lower bearing is smaller than the lubricating oil supply amount to the upper bearing,
Even with a cam bearing in which the width of the lower bearing is set smaller than the width of the upper bearing, leakage of lubricating oil in the lower bearing can be reduced, and a sufficient amount of lubricating oil can be supplied to the upper bearing. You can

According to the second aspect of the invention, since the oil groove functions as a so-called oil sump, the amount of lubricating oil supplied to the lower bearing is reduced in order to reduce leakage of lubricating oil in the lower bearing. Even if the above is satisfied, the lubricating oil is held in the oil groove in the upper bearing, so that a sufficient amount of lubricating oil can be always secured.

According to the third aspect of the present invention, the valve body is pushed by the wall surface of the lower bearing so that the oil supply hole faces the lower bearing as the camshaft rotates, and the oil supply hole faces the lower bearing. When the valve is closed and the oil supply hole moves to a position facing the oil groove with the rotation of the camshaft, the valve element enters the oil groove and opens the oil supply hole due to the centrifugal force generated by the rotation of the camshaft. Speak. Therefore, in the state where the oil supply hole faces the upper bearing, the amount of lubricating oil supplied from the oil supply hole is larger than that in the state where the oil supply hole faces the lower bearing.
Therefore, the leakage of the lubricating oil in the lower bearing can be reduced, and the lubricating oil in the upper bearing can be reliably supplied.

According to the fourth aspect of the invention, the lubricating oil is introduced from the lubricating introducing means into the oil introducing hole and the timing is appropriately set. Only the lubricating oil can be supplied. Further, according to the invention described in claim 5, either one of the oil introduction holes always supplies the lubricating oil to the upper bearing, so that the camshaft can be reliably lubricated.

[Brief description of drawings]

FIG. 1 is a view for explaining a lubrication structure according to a first embodiment of the present invention, and is a view showing a state in which an oil supply hole faces a cam upper journal.

FIG. 2 is a sectional view taken along the line AA in FIG.

FIG. 3 is a diagram for explaining the lubrication structure according to the first embodiment of the present invention, and is a diagram showing a state in which an oil supply hole faces a cam lower journal.

FIG. 4 is a sectional view taken along the line BB in FIG.

FIG. 5 is an exploded perspective view for explaining a bearing to which the lubricating structure according to the present invention is applied.

FIG. 6 is a diagram showing a structure of a camshaft which is supported by a bearing to which a lubricating structure according to the present invention is applied.

FIG. 7 is a diagram for explaining a lubricating structure according to a second embodiment of the present invention.

FIG. 8 is a plan view of a cam lower journal for explaining a lubricating structure according to a second embodiment of the present invention.

FIG. 9 is a perspective view of a cam lower journal for explaining a lubricating structure according to a second embodiment of the present invention.

FIG. 10 is a view for explaining the lubrication structure according to the second embodiment of the present invention, and is a view showing a state where the oil supply hole faces the cam lower journal.

FIG. 11 is a view for explaining the lubrication structure according to the second embodiment of the present invention, and is a view showing a state where the oil supply hole faces the cam upper journal.

FIG. 12 is a view for explaining the lubrication structure according to the third embodiment of the present invention, and is a view showing a state in which the valve body faces the cam upper journal.

FIG. 13 is a view for explaining the lubricating structure according to the third embodiment of the present invention, and is a view showing a state in which the valve body faces the cam lower journal.

FIG. 14 is a view for explaining the lubricating structure according to the fourth embodiment of the present invention, and is a view showing a state in which the valve body faces the cam upper journal.

FIG. 15 is a view for explaining the lubrication structure according to the fourth embodiment of the present invention, and is a view showing a state in which the valve body faces the cam lower journal.

FIG. 16 is a view for explaining a lubricating structure according to a fifth embodiment of the present invention, (A) shows a state where the oil introduction hole faces the cam upper journal, and (B) shows an oil supply. It is a figure showing the state where a hole has countered a cam upper journal.

FIG. 17 is a view for explaining a lubricating structure according to a fifth embodiment of the present invention, (A) shows a state where the oil introduction hole faces the cam lower journal, and (B) shows an oil supply. It is a figure showing the state where a hole has countered a cam lower journal.

FIG. 18 is a view for explaining a lubricating structure according to a sixth embodiment of the present invention, (A) shows a state in which the first oil introducing hole faces the cam upper journal, and (B) shows the same. FIG. 6 is a diagram showing a state in which a first oil supply hole faces a cam upper journal.

FIG. 19 is a view for explaining a lubricating structure according to a sixth embodiment of the present invention, (A) shows a state immediately before the first oil introducing hole separates from the cam upper journal, and (B) shows the same.
FIG. 8 is a diagram showing a state immediately before the first oil supply hole is separated from the cam upper journal.

FIG. 20 is a view showing a conventional lubricating structure, and is an enlarged perspective view showing the vicinity of a cam lower journal of a cam bearing.

FIG. 21 is a view showing a conventional lubricating structure, and is an enlarged plan view showing the vicinity of a cam lower journal of a cam bearing.

[Explanation of symbols]

 10 bearing 11 camshaft 12 cylinder head 13 cam lower journal 14 cam upper journal 15 valve lift hole 16 counterbore 18 journal part 19 camshaft inner passage 20 oil introduction hole 21 oil supply hole 22 oil introduction passage 24 oil groove 25, 29 journal Surface 26, 28 Valve body 27 Rib 30 Groove portion 31 Oil introduction groove 32 First camshaft inner passage 33 Second camshaft inner passage 34 First oil introduction hole 35 First oil supply hole 36 Second oil introduction Hole 37 Second oil supply hole 38 Partition wall

Claims (5)

[Claims] 1. A lubricating structure for a cam shaft bearing, wherein the cam shaft is configured to be supported by upper and lower bearings, and the width of the lower bearing is set smaller than the width of the upper bearing. A lubricating structure for a cam bearing, wherein the amount of lubricating oil supplied to the lower bearing is smaller than the amount of lubricating oil supplied. 2. The lubrication structure for a cam shaft bearing according to claim 1, wherein an oil supply hole for supplying lubricating oil in a radial direction is formed in the cam shaft, and the oil supply hole corresponds to the oil supply hole in the upper bearing. A lubrication structure for cam shaft bearings, characterized in that an oil groove is formed at the position. 3. The lubrication structure for a camshaft bearing according to claim 1, wherein an oil supply hole for supplying lubricating oil is formed in the camshaft in a radial direction, and the camshaft is slidable in the oil supply hole. A valve body is provided that is configured to open and close the oil supply hole by slidingly displacing the oil supply hole, and the oil supply hole moves to a position facing the oil groove as the camshaft rotates. In this case, a lubrication structure for a cam shaft bearing is provided, which is provided with a valve body moving mechanism that allows the valve body to move to a position where the lubricating oil supply path is formed. 4. The lubrication structure for a cam shaft bearing according to claim 1, wherein an oil introduction hole that is formed in the cam shaft in a radial direction and introduces lubricating oil, and that communicates with the oil introduction hole. A cam shaft inner passage formed in the axial direction of the cam shaft, and a lubricating oil formed in the radial direction and communicating with the cam shaft inner passage for introducing the lubricating oil introduced from the oil introduction hole into the upper and lower bearings. And an oil supply hole for supplying oil to the oil introduction hole are formed, and the lubricating oil is introduced into the oil introduction hole from the lubricating introduction means only when the oil supply hole faces the upper bearing. Lubricating structure of cam shaft bearing. 5. The lubricating structure for a camshaft bearing according to claim 4, wherein two camshaft internal passages are provided, and each camshaft internal passage is provided with the oil introduction hole and the oil supply, respectively, and A lubricating structure for a camshaft bearing, wherein the oil introducing holes respectively disposed in the camshaft internal passages are configured to communicate with the lubricating introducing means with a phase difference of 180 °.