JP5846374B2 - Camshaft thrust bearing lubrication structure - Google Patents

Description

  The present invention relates to a camshaft thrust bearing lubrication structure, and more particularly to a camshaft thrust bearing lubrication structure that supplies lubricating oil to a thrust bearing that regulates the movement of a camshaft for driving a valve of an engine in the thrust direction.

The engine supports a camshaft rotatably on a cylinder head by a cam housing, transmits the power of the crankshaft to the camshaft through a timing chain, and drives an intake valve and an exhaust valve by a cam provided on the camshaft. The camshaft is provided with a thrust plate on the shaft portion in order to restrict movement in the thrust direction. The thrust plate constitutes a thrust bearing by being rotatably inserted into a thrust plate groove provided in the cylinder head and the cam housing, and restricts the movement of the cam shaft in the thrust direction.
Conventional camshaft thrust bearing lubrication structures include those shown in FIGS. In the figure, 101 is an engine and 102 is a cylinder head cover. The engine 101 includes a valve operating chamber 104 in which a camshaft 103 is disposed inside a cylinder head cover 102 attached to a cylinder head, and a chain chamber 106 in which a timing chain 105 for transmitting power to the camshaft 103 is disposed. They are arranged adjacent to each other. The chain chamber 106 is covered with a chain cover attached to the cylinder head and the cylinder head cover 102.
A breather plate 108 is disposed between the inner surface 107 of the cylinder head cover 102 and the camshaft 103. A partition wall 109 extending from the inner surface 107 of the cylinder head cover 102 toward the breather plate 108 is formed in the cylinder head cover 102 along the chain chamber 106 covered with the chain cover. A breather chamber 110 is formed in a space adjacent to the valve operating chamber 104 and the chain chamber 106 by a breather plate 108 and a partition wall 109 inside the cylinder head cover 102.
A cam housing 112 that forms a bearing hole 111 between the valve head chamber 104 and the chain chamber 106 is formed between the valve head chamber 104 and the chain chamber 106. The cam housing 112 is attached to the cylinder head, and rotatably supports the shaft portion 113 of the camshaft 103 in the bearing hole 111. The camshaft 103 drives each valve for intake and exhaust by a cam provided on the shaft portion 113. A cam sprocket 114 that meshes with the timing chain 105 is attached to a shaft 113 that protrudes from the bearing hole 111 of the camshaft 103 toward the chain chamber 106.

A disc-shaped thrust plate 115 is disposed on a shaft portion 113 that protrudes from the bearing hole 111 of the cam shaft 103 toward the valve operating chamber 104. The cam housing 112 is provided with a thrust plate groove 116 into which the upper semicircular portion of the thrust plate 115 is rotatably inserted. In addition, the cylinder head is provided with a thrust plate groove that is paired with the thrust plate groove 116 of the cam housing 112 and into which the lower semicircular portion of the thrust plate 115 is rotatably inserted. The camshaft 103 constitutes a thrust bearing 117 by rotatably inserting the thrust plate 115 into the thrust plate groove 116 of the cam housing 112 and the thrust plate groove of the cylinder head, and the thrust bearing 117 restricts movement in the thrust direction. Is done.
In this lubricating structure of the thrust bearing 117, an expanded portion 118 that opens upward at least a part of the thrust plate groove 116 of the cam housing 112 is provided on the upper portion of the cam housing 112. During operation of the engine 101, the lubricating oil is scattered (arrow A) in the rotational circumferential direction of the timing chain 105, and then collides with the inner side surface 107 of the cylinder chamber cover 106 at the upper part of the chain chamber 106 and falls to the lower part. Go (arrow B). The lubricating structure of the thrust bearing 117 is such that the falling lubricating oil is received by the upper surface 119 of the cam housing 112 and flows to the thrust bearing 117 side (arrow C), and the thrust plate is opened from the expanding portion 118 that opens to the upper portion of the cam housing 112. The thrust plate 114 of the camshaft 103 is lubricated by flowing into the groove 116 (arrow D).

  In such a camshaft thrust bearing lubrication structure, a cam plate is provided with a thrust plate groove into which the camshaft thrust plate is rotatably inserted, and an expansion portion in which a part of the thrust plate groove opens is provided in the cam housing. There is one in which a concave lubricating oil sump is formed on at least one side of the expanding portion in the rotational direction of the thrust plate. (Patent Document 1: JP 2003-222003 A)

JP 2003-222003 A

By the way, in the lubricating structure of the thrust bearing 117 of the camshaft 103 shown in FIGS. 4 to 6, the gap with respect to the peripheral parts is small, and the shape of the upper surface 119 of the cam housing 112 is used to guide the lubricating oil to the expanding portion 118. The optimal shape may not be achieved.
For this reason, in the lubricating oil supply path (arrows A to C) shown in FIGS. 4 to 6 described above, only a part of the lubricating oil transmitted through the upper surface 119 of the cam housing 112 can be guided to the thrust plate 115, and lubrication is performed. May be insufficient.
In particular, when there is one thrust plate 115 of the camshaft 103 and the thrust plate 115 is disposed on the side away from the timing chain 105 with respect to the cam housing 112, the cam of the thrust plate 115 from the cam housing 112 side. Since the lubricating oil flows toward the facing surface 120 on the side facing the housing 112, it is easy to positively supply the lubricating oil to the facing surface 120, while the back surface located on the opposite side of the facing surface 120. In 121, the supply of lubricating oil is insufficient.
Accordingly, in the thrust bearing lubrication structure shown in FIGS. 4 to 6, the thrust plate 115 of the camshaft 103 may be abnormally worn, and the thrust plate groove 115 of the cam housing 112 and the thrust plate groove of the cylinder head may be abnormally worn. .

  An object of the present invention is to reliably lubricate a thrust plate of a camshaft and a thrust plate groove into which the thrust plate is rotatably inserted, thereby improving the lubricity of the thrust bearing.

  According to the present invention, a valve operating chamber in which a camshaft is disposed inside a cylinder head cover attached to a cylinder head of an engine and a chain chamber in which a timing chain for transmitting power to the camshaft is disposed are adjacent to each other. The valve chamber by a breather plate disposed between the inner surface of the cylinder head cover and the camshaft, and a partition wall extending from the inner surface of the cylinder head cover to the breather plate side along the chain chamber. A breather chamber is formed in a space adjacent to the chain chamber, and a cam housing is formed at the boundary between the valve operating chamber and the chain chamber to form a bearing hole between the cylinder head. A camshaft is rotatably supported and protrudes from the bearing hole of the camshaft toward the valve operating chamber. A disc-shaped thrust plate is disposed on the shaft portion to be provided, a thrust plate groove into which the thrust plate is rotatably inserted is provided in the cam housing, and an expanded portion that opens at least a part of the thrust plate groove upward is provided. In the thrust bearing lubrication structure of the camshaft provided at the upper portion of the cam housing, an enlarged portion as a space extending upward of the thrust plate is formed in the chain chamber, and the outer edge portion of the breather plate is below the enlarged portion. An extending protrusion is formed, and an opening is formed in the protrusion to drop the lubricating oil accumulated on the upper surface side of the protrusion onto the thrust plate.

The present invention introduces lubricating oil that scatters upward when the timing chain rotates into an enlarged portion of the chain chamber that extends upward of the thrust plate, and the upper surface side of the protruding portion of the breather plate formed to extend downward of the enlarged portion Lubricating oil can be stored in And lubricating oil can be dripped at a thrust plate from the opening part formed in the protrusion part.
Therefore, the present invention can reliably lubricate the thrust plate disposed in the valve chamber and the thrust plate groove into which the thrust plate is rotatably inserted by the lubricating oil that the timing chain jumps up, thereby improving the lubricity of the thrust bearing. Can be improved.

FIG. 1 is a sectional view of a thrust bearing lubrication structure. (Example) FIG. 2 is a plan view of the breather plate according to arrow II in FIG. (Example) FIG. 3 is a cross-sectional view of the cylinder head portion of the engine. (Example) FIG. 4 is a perspective view of a thrust bearing lubrication structure. (Conventional example) FIG. 5 is a cross-sectional view taken along line VV in FIG. (Conventional example) FIG. 6 is a bottom view of the cam housing. (Conventional example)

  Embodiments of the present invention will be described below with reference to the drawings.

1 to 3 show an embodiment of the present invention. In FIG. 3, 1 is an engine, 2 is a cylinder head, 3 is a cylinder head cover, and 4 is a chain cover. The engine 1 includes a valve operating chamber 6 in which a camshaft 5 is disposed inside a cylinder head cover 3 attached to the cylinder head 2, and a chain chamber 8 in which a timing chain 7 for transmitting power to the camshaft 5 is disposed. It arrange | positions so that it may mutually adjoin. The chain chamber 8 is covered with a chain cover 4 attached to the cylinder head 2 and the cylinder head cover 3.
A breather plate 10 is disposed between the inner surface 9 of the cylinder head cover 3 and the camshaft 5. The cylinder head cover 3 is formed with a partition wall 11 extending from the inner surface 9 of the cylinder head cover 3 toward the breather plate 10 along the chain chamber 8 covered by the chain cover 4. Inside the cylinder head cover 3, a breather chamber 12 is formed in a space adjacent to the valve operating chamber 6 and the chain chamber 8 by a breather plate 10 and a partition wall 11.
A cam housing 14 that forms a bearing hole 13 between the valve head chamber 6 and the chain chamber 8 is formed between the valve head chamber 6 and the chain chamber 8 and the cylinder head 2 as shown in FIG. The cam housing 14 is provided with a semi-cylindrical bearing portion 15 that forms a bearing hole 13. The cylinder head 2 is provided with a semi-cylindrical bearing portion 16 which is paired with the bearing portion 15 of the cam housing 14 and forms a bearing hole 13. The cam housing 14 is attached to the cylinder head 2 to form a bearing hole 13, and the shaft portion 17 of the camshaft 5 is rotatably supported in the bearing hole 13. The camshaft 5 drives each valve 19 for intake and exhaust by a cam 18 provided on the shaft portion 17 (see FIG. 3).

As shown in FIG. 1, a cam sprocket 20 that meshes with the timing chain 7 is attached to the shaft portion 17 of the camshaft 5 that protrudes from the bearing hole 13 toward the chain chamber 8. A disc-shaped thrust plate 21 is disposed on the shaft portion 17 protruding from the bearing hole 13 of the camshaft 5 toward the valve operating chamber 6. The thrust plate 21 has a facing surface 22 on the side facing the cam housing 14, and a back surface 23 opposite to the cam housing 14 on the side opposite to the facing surface 22.
As shown in FIG. 2, the cam housing 14 is provided with a thrust plate groove 24 into which the upper semicircular portion of the thrust plate 21 is rotatably inserted. As shown in FIG. 1, the cylinder head 2 is provided with a thrust plate groove 25 which is paired with the thrust plate groove 24 of the cam housing 14 and into which the semicircular portion on the lower side of the thrust plate 21 is rotatably inserted. Yes. The camshaft 5 constitutes a thrust bearing 26 by rotatably inserting the thrust plate 21 into the thrust plate groove 24 of the cam housing 14 and the thrust plate groove 25 of the cylinder head 2, and the thrust bearing 26 moves in the thrust direction. Be regulated.

As shown in FIG. 2, the lubricating structure of the thrust bearing 26 is provided with an expanding portion 27 that opens at least a part of the thrust plate groove 24 of the cam housing 14 at the upper portion of the cam housing 14. The expanding portion 27 is formed so as to expand upward from the opening portion of the thrust plate groove 24, and as shown in FIG. 1, the lubricating oil that has been scattered and dropped in the rotational circumferential direction of the timing chain 7 is thrust. By pouring into the plate groove 24, the thrust plate 21 of the camshaft 5 is lubricated.
As shown in FIG. 1, the lubricating structure of the thrust bearing 26 is such that the partition wall 11 extending from the inner surface 9 of the cylinder head cover 3 to the cylinder head 2 side is disposed at a position beyond the thrust plate 21 in the direction away from the chain chamber 8. As a result, an enlarged portion 28 of a space extending upward of the thrust plate 21 is formed in the chain chamber 8. On the outer edge of the breather plate 10 on the side of the chain chamber 8, a protruding portion 29 extending downward from the enlarged portion 28 is formed so as to cover the cam housing 14. The protrusion 29 is formed with an opening 31 that drops from the inner surface 9 of the cylinder head cover 3 and drops the lubricating oil accumulated on the upper surface 30 side of the protrusion 29 onto the thrust plate 21.
As shown in FIG. 1, when the link end 32 of the timing chain 7 is a and the reverse surface 23 of the thrust plate 21 of the camshaft 5 is b, the protruding portion 29 has an installation range between a and b. . Further, as shown in FIG. 2, the opening 31 of the projecting portion 29 coincides with a center plane L disposed between the opposing surface 22 and the anti-back surface 23 of the thrust plate 21 of the camshaft 5. It is provided on the upper part of the cam housing 14. The shape of the opening 31 is a square of e * f where the thickness of the thrust plate 21 is c, the radial length of the thrust plate 21 is d, the width of the opening 31 is e, and the length is f. The shape or an elliptical shape with a short radius e and a long radius f is used. Note that c to f have a relationship of c ≦ e and d ≦ f.

As shown in FIG. 1, the lubricating oil splashed in the rotation circumferential direction of the timing chain 7 (arrow A) collides with the inner side surface 9 of the enlarged portion 28 connected to the chain chamber 8 of the cylinder head cover 3 and moves downward. It will fall (arrow B). The lubricating structure of the thrust bearing 26 receives and collects the falling lubricating oil by a protruding portion 29 extending downward from the enlarged portion 28. In the lubricating structure of the thrust bearing 26, the lubricating oil recovered by the protruding portion 29 is transmitted along the upper surface 30 of the protruding portion 29 (arrow C) and dropped from the opening 31 of the protruding portion 29 onto the thrust plate 21 to be thrust plate groove 24. -The thrust plate 21 of the camshaft 5 is lubricated by being poured into 25 (arrow D).
As described above, the lubricating structure of the thrust bearing 26 introduces lubricating oil that scatters upward when the timing chain 7 rotates into the enlarged portion 28 of the chain chamber 8 extending upward of the thrust plate 21, and below the enlarged portion 28. Lubricating oil can be stored on the upper surface 30 side of the protruding portion 29 of the breather plate 9 formed to extend. Then, the lubricating oil accumulated on the upper surface 30 side of the protruding portion 29 can be dropped onto the thrust plate 21 from the opening 31 formed in the protruding portion 29.
For this reason, the thrust bearing 26 has a lubricating structure in which the thrust plate 21 disposed in the valve operating chamber 6 and the thrust plate groove 24. 25 can be reliably lubricated, and the lubricity of the thrust bearing 26 can be improved. Further, the lubrication structure of the thrust bearing 26 does not have to transmit the upper surface of the cam housing 14 and guide the lubricating oil to the thrust plate 21 as in the prior art, so that the degree of freedom of the layout of the cam housing 14 is increased. it can.
Further, in the lubricating structure of the thrust bearing 26, a flange portion 34 that protrudes toward the cylinder head cover 3 is formed at the outer end portion 33 of the protrusion 29 on the chain chamber 8 side.
As a result, the lubricating structure of the thrust bearing 26 can reliably store the lubricating oil on the upper surface 30 side of the protruding portion 29 by the flange portion 34, and can improve the rigidity of the protruding portion 29 and prevent vibration.

  The present invention can improve the lubricity of a thrust bearing of a camshaft, and can be applied to improve the lubrication of a thrust bearing of a rotating body, not limited to the camshaft.

DESCRIPTION OF SYMBOLS 1 Engine 2 Cylinder head 3 Cylinder head cover 4 Chain cover 5 Cam shaft 6 Valve chamber 7 Timing chain 8 Chain chamber 9 Inner side surface 10 Breather plate 11 Bulkhead 12 Breather chamber 13 Bearing hole 14 Cam housing 17 Shaft part 20 Cam sprocket 21 Thrust plate 24 Thrust plate groove 25 Thrust plate groove 26 Thrust bearing 27 Widened portion 28 Widened portion 29 Projected portion 30 Upper surface 31 Opened portion 34 Flange portion

Claims (2)

  A valve operating chamber in which a camshaft is arranged inside a cylinder head cover attached to a cylinder head of an engine and a chain chamber in which a timing chain for transmitting power to the camshaft is arranged adjacent to each other, and the cylinder The valve operating chamber and the chain chamber are formed by a breather plate disposed between an inner surface of the head cover and the camshaft, and a partition wall extending from the inner surface of the cylinder head cover toward the breather plate along the chain chamber. A breather chamber is formed in a space adjacent to the cam housing, and a cam housing is formed at the boundary between the valve operating chamber and the chain chamber to form a bearing hole between the cylinder head, and the camshaft is rotated in the bearing hole. Freely supported on the shaft that protrudes from the bearing hole of the camshaft toward the valve chamber A plate-like thrust plate is disposed, a thrust plate groove into which the thrust plate is rotatably inserted is provided in the cam housing, and an expanded portion that opens upward at least a part of the thrust plate groove is formed in the cam housing. In the thrust bearing lubrication structure of the camshaft provided on the upper part, an enlarged part as a space part extending upward of the thrust plate is formed in the chain chamber, and a projecting part extending below the enlarged part at an outer edge part of the breather plate The thrust bearing lubrication structure for a camshaft is characterized in that an opening for dripping the lubricating oil accumulated on the upper surface side of the protrusion to the thrust plate is formed in the protrusion.   2. The camshaft thrust bearing lubrication structure according to claim 1, wherein a flange portion protruding toward the cylinder head cover is formed at an outer end portion of the protrusion. 3.

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