JP2009215991A - Lubricating structure for valve train - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lubricating structure for a valve train capable of securing lubrication of the valve train and reducing discharge loss of lubricating oil from a pump. <P>SOLUTION: This structure includes a valve lifter supply oil passage 42 having an oil filler 41a of a lubricating oil passage 41 opening to a bearing surface 33 of a journal part, an introduction port 42a opening to the bearing surface 33, and a jet port 42b opening toward the valve lifter 26; and a communication passage 45 having a first opening part 45a and a second opening part 45b opening to a circumference surface 36a of a cam journal part 36. A valve lifter oil supply passage having the first opening part 45a communicate to the oil filler 41a and the second opening part 45b communicate to the introduction port 42a with accompanying rotation of a camshaft 35, and a bearing surface oil supply passage having the second opening part 45b communicate to the oil filler 41a and the first opening part 45a open toward a maximum axial load receiving section 33c of the bearing surface 33 are formed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a lubrication structure for a valve mechanism, and more particularly to a lubrication structure for a valve mechanism having a valve lifter that opens and closes an intake / exhaust valve by rotation of a camshaft rotatably supported on a bearing surface formed on a cylinder head. About.

  2. Description of the Related Art Conventionally, in an engine, there is a drive mechanism that has a cam shaft and a valve lifter coupled to an intake / exhaust valve and periodically opens and closes the intake / exhaust valve by rotation of the cam shaft.

  In this type of valve mechanism, in order to obtain a smooth operation over a long period of time, lubricating oil is applied between the cam serving as the sliding surface and the valve lifter and between the bearing surface and the cam journal portion of the cam shaft. It is necessary to supply.

  For example, Patent Document 1 discloses a technique for supplying lubricating oil between the cam and the valve lifter and to the bearing surface and the cam journal portion. The lubrication structure of Patent Document 1 will be described with reference to FIGS. 11 to 13.

  FIG. 11 is a longitudinal sectional view showing the main part of the valve operating mechanism, FIG. 12 is a plan view with a part broken away showing the main part, and FIG. 13 is an enlarged vertical view showing the main part.

  As shown in FIG. 11, a lubricating oil passage 102 is formed in the axial center hollow portion of the camshaft 101. A pair of cams 103 are integrally formed on the cam shaft 101 so as to be separated from each other in the axial direction as shown by phantom lines in FIG. 12, and a cam journal portion 104 is formed between the cams 103. As shown in FIG. 13, the cam journal portion 104 is rotatably supported on a bearing surface 113 formed by a journal bearing 111 formed on the cylinder head and a cam cap 112 bolted to the journal bearing 111.

  An oil supply hole 105 is formed in the cam journal portion 104 of the cam shaft 101 in the radial direction. The oil supply hole 105 is an intermediate portion between the substantially semicircular base portion 103a and the cam nose portion 103c of the cam 103 when viewed from the axial direction. It is formed at a position that matches the lamp portion 103b.

  On the other hand, a lubricating oil groove 114 is recessed in the inner peripheral surface 113a of the journal bearing 111 forming the bearing surface 113 as shown in FIG. The lubricating oil groove 114 is provided on the inner peripheral surface 113a of the journal bearing 111 at the tip of the intake valve 115 on both sides in communication with the lubricating oil introducing groove 114a extending from the vicinity of the top to the bottom. It comprises a pair of lubricating oil ejection groove portions 114b extending obliquely downward toward the sliding contact surface between the valve lifter 116 and the cam 103.

  When the oil supply hole 105 faces the upper end portion of the lubricating oil introduction groove 114a of the lubricating oil groove 114 as the cam shaft 101 rotates, the lubricating oil in the lubricating oil passage 102 passes through the lubricating oil introduction hole 105 and enters the lubricating oil introduction groove 114a. The amount of inflow further increases as the camshaft 101 rotates. Immediately before the ramp portion 103b of the cam 103 comes into contact with the valve lifter 116, the lubricating oil filled in the lubricating oil introduction groove portion 114a is ejected from each lubricating oil outlet portion 114b toward the contact surface between the valve lifter 116 and the cam 103. Is done. Lubricating oil is also supplied between the outer peripheral surface of the cam journal portion 104 of the cam shaft 101 and the bearing surface 113.

Japanese Utility Model Publication No. 7-30305

  According to Patent Document 1, as the cam shaft 101 rotates, the contact surface between the cam 103 and the valve lifter 116 and the cam journal portion 104 of the cam shaft 101 and the bearing surface 113 are connected via the oil supply hole 105 and the lubricating oil groove 114. Lubricating oil can be supplied between them.

  However, since the lubricating oil is always supplied from the oil supply hole 105 between the cam journal portion 104 and the bearing surface 113, there is a concern that the discharge loss of the lubricating oil from the oil pump increases.

  Accordingly, an object of the present invention made in view of such a point is to provide a lubrication structure for a valve operating mechanism that can ensure lubrication of the valve operating mechanism and reduce the loss of discharge of lubricating oil from the pump.

  The lubricating structure for a valve operating mechanism according to claim 1, which achieves the above object, includes a cam shaft having a cam journal portion rotatably supported on a bearing surface formed on a cylinder head, and accompanying rotation of the cam shaft. In a lubrication structure of a valve mechanism having a valve lifter that opens and closes an intake / exhaust valve by contact with a cam surface, a lubricating oil passage having an oil supply port opening on the bearing surface, and an inlet port opening on the bearing surface and an upper surface of the valve lifter And a communication passage formed in the cam journal portion having a first opening and a second opening that are opened on a peripheral surface of the cam journal portion. A valve lifter oil supply passage in which the first opening communicates with the oil supply port and the second opening communicates with the introduction port as the camshaft rotates according to the open / close state of the intake / exhaust valve, and the second opening comprises At the filler port First opening through which is characterized in that the bearing surface the oil supply passage which is open toward the bearing surface is formed.

  According to this invention, as the camshaft rotates according to the open / close state of the intake / exhaust valve, the first opening communicates with the oil supply port and the second opening communicates with the introduction port to supply the lubricating oil to the valve lifter. And a bearing surface oil supply passage in which the second opening communicates with the oil supply port and the first opening opens toward the bearing surface, the contact surface between the cam surface of the cam and the valve lifter, and the cam journal portion and the bearing. Lubricating oil is supplied intensively between the surfaces.

  In addition, the oil supply port of the lubricating oil passage is blocked by the peripheral surface of the cam journal portion during a period when the first opening or the second opening of the communication passage is not opposed to the oil supply port of the lubricating oil passage. Pump ejection loss can be significantly reduced.

  According to a second aspect of the present invention, in the lubricating structure of the valve operating mechanism according to the first aspect, the valve lifter oil supply passage in which the first opening communicates with the oil supply port and the second opening communicates with the introduction port has a cam surface. It is formed immediately before starting contact with the valve lifter.

  According to this invention, lubricating oil is concentratedly supplied to the cam surface of the cam and the valve lifter at the most preferable timing immediately before the cam surface of the cam starts to contact the valve lifter. A thick oil film can be efficiently formed over a wide area.

  According to a third aspect of the present invention, in the lubricating structure of the valve operating mechanism according to the first or second aspect, the bearing surface oil supply wherein the second opening portion communicates with the oil supply port and the first opening portion opens toward the bearing surface. The path is formed at the maximum head, and the first opening is opposed to the maximum axial load receiving portion of the bearing surface.

  According to the present invention, the lubricating oil is intensively supplied facing the maximum axial load receiving portion of the bearing surface at the maximum lift when the bearing load acting on the bearing surface is maximized by the rotation of the camshaft.

  According to a fourth aspect of the present invention, in the lubricating structure for a valve operating mechanism according to the third aspect, the maximum axial load receiving portion is a cam cap bearing surface of a cam cap coupled to a journal portion of a cylinder head. And

  According to the present invention, the lubricating oil is intensively supplied facing the cam cap bearing surface of the cam cap at the maximum lift when the bearing load acting on the bearing surface is maximized by rotation of the cam shaft.

  According to the present invention, during the rotation of the cam shaft, lubricating oil is efficiently and intensively supplied to the cam surface of the cam, the valve lifter and the bearing surface.

  In addition, during the period when the camshaft is rotating and the lubricating oil is not supplied to the cam surface, valve lifter, and bearing surface of the cam, the oil supply port of the lubricating oil passage is blocked by the peripheral surface of the cam journal. Pump ejection loss can be greatly reduced.

  Hereinafter, an embodiment of a lubrication structure for a valve operating mechanism according to the present invention will be described with reference to FIGS. 1 to 10 by taking an example of a lubrication structure for a valve operating mechanism for opening and closing an intake valve.

  1 is a longitudinal sectional view of a cylinder head showing an outline of a lubricating structure, FIG. 2 is a plan view of the main part of the cylinder head, FIG. 3 is a sectional view taken along the line II of FIG. 2, and FIG. FIG. 5 and FIG. 5 to FIG.

  As shown in FIGS. 1 and 2, the cylinder head 10 has a box shape having an upper deck 11, a lower deck 12, and a sidewall 13, and an upper portion is partitioned by a partition wall 14 continuously formed on the upper deck 11 and the sidewall 13. The lower surface is coupled to a cylinder block (not shown).

  An intake port 16 extending between the lower deck 12 and the upper deck 11 is formed from a combustion chamber 15 formed on the lower surface of the cylinder head 10 corresponding to a plurality of cylinders arranged side by side in the cylinder block. An annular valve seat 17 is attached to the opening on the chamber 15 side. A cylindrical valve guide 18 is attached to the intake port 16. A cylindrical valve lifter guide 19 is formed coaxially with the valve guide 18 in the upper deck 11 adjacent to the partition wall 14.

  The intake valve 21 that opens and closes the intake port 16 includes a rod-like stem 22 that slidably passes through the valve guide 18 and a valve head 23 that is integrally formed with the stem 22, and the tip of the stem 19 that protrudes from the upper deck 11. The valve face 23a of the valve head 23 is seated on the valve seat 17 by the valve spring 25 elastically mounted between the retainer 24 attached in the vicinity and the upper deck 11, and closes the intake port 16 to the closed position shown in FIG. Be energized.

  At the tip of the stem 22 is a cup-like shape having a disc-shaped cam sliding contact surface 26 a covering the upper half of the valve spring 25 and a cylindrical body portion 26 b slidably fitted and held on the valve lifter guide 19. A valve lifter 26 is attached.

  On the other hand, the cam shaft 35 rotates on the bearing surface 33 formed by the journal bearing surface 33 a of the journal bearing 31 formed in the partition wall 14 and the cam cap bearing surface 33 b of the cam cap 32 coupled to the journal bearing 31 by the bolt 30. It is supported freely.

  The cam shaft 35 is spaced apart in the axial direction on both sides of a cam journal portion 36 that is pivotally supported by the bearing surface 33, thereby forming a pair of cams 38. The cam 38 has a substantially semicircular base portion 39a, a cam nose portion 39c, and a cam surface 39 on which ramp portions 39b and 39d between the base portion 39a and the cam nose portion 39c are continuously formed.

  The base portion 39 a of the cam surface 39 is formed in a non-contact state with the cam sliding contact surface 26 a of the valve lifter 26. On the other hand, when the cam 38 rotates with the rotation of the cam shaft 35, the ramp portion 39 b of the cam surface 39 contacts and slides against the cam sliding contact surface 26 a of the valve lifter 26 and resists the bias of the valve spring 25 through the valve lifter 26. When the intake valve 21 is pressed, the valve face 23a moves away from the valve seat 17 from the valve closing position, and the lift, that is, the lift, in which the gap between the valve face 23a and the valve seat 17 increases, is started.

  When the cam nose portion 39c of the cam surface 39 is slidably pressed against the cam sliding contact surface 26a of the valve lifter 26 by further rotation of the cam shaft 35, the gap between the valve face 23a and the valve seat 17 is maximized as shown in FIG. Maximum lift position.

  Further, when the cam shaft 35 rotates, the valve face 23a of the intake valve 21 urged by the valve spring 25 while the ramp portion 39d is slidably contacting the cam sliding contact surface 26a of the valve lifter 26 as the cam 38 rotates is turned into the valve seat 17. , The gap between the valve face 23a and the valve seat 17 decreases.

  When the cam shaft 35 further rotates and the cam surface 39 moves away from the cam sliding contact surface 26a of the valve lifter 26 and the pressing of the valve lifter 26 by the cam surface 39 is released, the valve face 23a of the valve head 23 is shown in FIG. Sits on the valve seat 17 and closes the intake port 16.

  The bearing load acting on the bearing surface 33 due to the rotation of the cam shaft 35 is maximized at the maximum lift when the valve spring 25 shown in FIG. 7 is compressed to the maximum, and the cam nose portion 39c as viewed from the extending direction of the cam shaft 35. The bearing load at the portion of the bearing surface 33 on the opposite side becomes the maximum, and this portion becomes the maximum axial load receiving portion 33c.

  On the other hand, as shown in FIGS. 1 and 2, a lubricating oil passage 41 to which lubricating oil is supplied from the oil pump P is formed in the sidewall 13 and the partition wall 14 of the cylinder head 10, and the lubricating oil passage is formed as shown in FIG. 41 is provided in the journal bearing surface 33 a of the journal bearing 31.

  Further, the journal bearing 31 is spaced apart from the oil supply port 41a in the circumferential direction of the journal bearing surface 33a, and an introduction port 42a is opened in the journal bearing surface 33a, and the cam sliding contact surface 26a of the valve lifter 26 and the cam 38 are in the valve closing position. A valve lifter supply oil passage 42 is formed between the contact surfaces with the cam surface 39a.

  An oil hole having a first opening 45a and a second opening 45b opened on the peripheral surface 36a of the cam journal portion 36 corresponding to the oil supply port 41a and the introduction port 42a that open to the journal bearing 31 during rotation of the cam shaft 35, respectively. A communication path 45 is formed. As shown in FIGS. 7 and 8, the second opening 45b of the communication passage 45 formed in the cam journal portion 36 is at the rotational position of the cam shaft 35 corresponding to the oil supply port 41a that opens to the cam journal portion 36. The first opening 45 a is set at a position where the first opening 45 a opens facing the maximum axial load receiving portion 33 c of the bearing surface 33.

  5 and 6 immediately before the ramp 39b of the cam surface 39 starts to contact the cam sliding contact surface 26a of the valve lifter 26, in other words, the cam shaft 35 immediately before the intake valve 21 starts the lift. In the rotational position, the first opening 45a faces the oil supply port 41a, the lubricating oil passage 41 and the communication passage 45 communicate with each other, and the second opening 45b faces the introduction port 42a to form the communication passage 45 and the valve lifter oil supply passage. Is done. 7 and 8, the second opening 45b is opposed to the oil supply port 41a at the rotational position of the cam shaft 35 at the maximum lift shown in FIG. 7 and FIG. It is formed.

  Next, the operation of the lubrication structure of the valve mechanism configured as described above will be described.

  As shown in FIG. 1, when the intake valve 21 in which the cam surface 39 of the cam 38 formed on the cam shaft 35 is separated from the cam sliding contact surface 26a of the valve lifter 26 is in the valve closing position, as shown in FIG. The inlet 42a of the lubrication passage 41 that opens to the center is closed by the peripheral surface 36a of the cam journal portion 36 of the cam shaft 35, and the supply of the lubricating oil from the lubrication passage 41 is stopped.

  The cam shaft 35 rotates and reaches the rotational position of the cam shaft 35 immediately before the ramp portion 39b of the cam surface 39 shown in FIG. 5 starts to contact the cam sliding contact surface 26a of the valve lifter 26, that is, immediately before the lift of the intake valve 21 starts. Then, as shown in FIG. 6, the first opening 45 a of the communication passage 45 formed in the cam journal portion 36 faces the oil supply port 41 a and the second opening 45 b faces the introduction hole 42 a of the valve lifter supply oil passage 42. Thus, a valve lifter oil supply passage extending from the lubricant oil passage 41 to the valve supply oil passage 42 via the communication passage 45 is formed, and the lubricating oil from the lubricant oil passage 41 passes through the jet outlet 42a and the cam sliding contact surface 26a of the valve lifter 26 and the cam 38. Are ejected toward the cam surface 39, particularly toward the lamp portion 39b. Accordingly, the lubricating oil is intensively ejected onto the ramp portion 39b of the cam 38 and the cam sliding contact surface 26a of the valve lifter 26 at the most preferable timing immediately before the ramp portion 39b starts to contact the cam sliding contact surface 26a. A thick oil film is efficiently formed over a wide range of the contact surface between the cam 38 and the valve lifter 26.

  Further, when the cam shaft 35 rotates, the oil supply port 41a of the lubrication passage 41 that opens to the journal bearing portion 33a is closed by the peripheral surface 36a of the cam journal portion 36, and the supply of the lubricating oil from the lubrication passage 41 is stopped, and the cam The ramp portion 39b of the surface 39 comes into contact with and slides on the cam sliding contact surface 26a of the valve lifter 26, and the lift of the intake valve 21 is started.

  When the cam shaft 35 further rotates and reaches the rotational position of the cam shaft 35 at the maximum travel where the bearing load acting on the bearing surface 33 shown in FIG. 7 becomes maximum, as shown in FIG. The second opening 45b that opens is opposed to the oil supply port 41a that opens to the journal bearing surface 33a of the journal bearing 31, and the first opening 45a is opposed to the maximum axial load receiving portion 33c of the journal bearing surface 33, so that the lubricating oil path A bearing surface oil supply passage is formed from 41 to the maximum axial load receiving portion 33c via the communication passage 45, and the lubricating oil is supplied from the lubricating oil passage 41 to the maximum axial load receiving portion 33c from the first opening 45a. Thereby, an oil film is formed on the cam cap bearing surface 33b of the cam cap 32 to which the bearing load is most applied at the maximum stroke.

  When the cam shaft 35 further rotates, the oil supply port 41a of the lubrication passage 41 that opens to the journal bearing portion 33a is closed by the peripheral surface 36a of the cam journal portion 36, and the supply of lubricant oil from the lubrication passage 41 stops and the cam surface The ramp portion 39d of the valve 39 contacts and slides on the cam sliding contact surface 26a of the valve lifter 26, the valve face 23a of the intake valve 21 approaches the valve seat 17, and the gap between the valve face 23a and the valve seat 17 decreases. When the cam shaft 35 further rotates and the cam surface 39 moves away from the cam sliding contact surface 26a of the valve lifter 26 and the pressing of the valve lifter 26 by the cam surface 39 is released, the valve face 23a of the valve head 23 is seated on the valve seat 17. Then, the intake port 16 is closed.

  Therefore, during the rotation of the cam shaft 35, the lubricating oil is supplied at the most preferable timing immediately before the ramp portion 39b of the cam 38 starts to contact the cam sliding contact surface 26a of the valve lifter 26. 26, the thick oil film can be efficiently formed over a wide area of the mutual contact surface between the cam 38 and the valve lifter 26. Further, when the camshaft 35 rotates and the maximum lift at which the bearing load acting on the bearing surface 33 is maximized, the lubricating oil is intensively supplied facing the maximum shaft load receiving portion 33c of the journal bearing surface 33, and the maximum lift. An oil film is formed on the cam cap bearing surface 33b of the cam cap 32 to which a bearing load is sometimes applied.

  Moreover, during the rotation of the cam shaft 35, the bearing load acting on the bearing surface 33 immediately before the ramp portion 39b of the cam 38 starts to contact the cam sliding contact surface 26a of the valve lifter 26 and as the cam shaft 35 rotates. During the period when the first opening 45a or the second opening 45b of the communication passage 45 is not opposed to the oil supply port 41a of the lubricating oil passage 41 except at the time of the maximum lift, the oil supply port 41a of the lubricating oil passage 41 is Since it is blocked by the peripheral surface 36a of the cam journal portion 36, the lubricating oil is not ejected from the oil supply port 41a of the lubricating oil passage 41, and the ejection loss of the oil pump P can be significantly reduced.

  In addition, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the meaning of invention. For example, in the above embodiment, the communication passage 45 is formed by the oil hole drilled in the journal portion 36. However, as shown in the sectional view of the journal portion 36 corresponding to FIG. It can also be formed by a communication groove 46 recessed in the peripheral surface 36a of the cam journal portion 36 having a first opening 46a and a second opening 46b respectively corresponding to the oil supply port 41a and the introduction port 42a. When the second opening 46 b of the communication groove 46 formed in the cam journal 36 is in the rotational position of the cam shaft 35 corresponding to the oil supply port 41 a that opens in the cam journal 36, the first opening 46 a is the bearing surface 33. Is set at a position corresponding to the maximum axial load receiving portion 33c.

  Further, as shown in a cross-sectional view corresponding to FIG. 3 in FIG. 10, the valve lifter supply oil passage 42 is recessed in the journal bearing surface 33a of the journal bearing 31 from the inlet port 42a to the jet port 42b instead of the oil hole. It can also be formed by a concave groove 47.

  In the above embodiment, the lubrication structure of the valve mechanism that opens and closes the intake valve has been described as an example. However, the present invention can be applied to the lubrication structure of the valve mechanism that opens and closes the exhaust valve.

It is a longitudinal cross-sectional view of the cylinder head which shows the outline | summary of the lubrication structure of the valve mechanism which concerns on embodiment of this invention. It is a principal part top view of a cylinder head. It is the II sectional view taken on the line of FIG. It is a principal part longitudinal cross-sectional view of a journal part. It is a longitudinal cross-sectional view of the cylinder head corresponding to FIG. It is a principal part longitudinal cross-sectional view of the journal part corresponding to FIG. 4 explaining an action | operation. It is a longitudinal cross-sectional view of the cylinder head corresponding to FIG. It is a principal part longitudinal cross-sectional view of the journal part corresponding to FIG. 4 explaining an action | operation. It is a principal part longitudinal cross-sectional view of the journal part corresponding to FIG. 4 which shows the outline | summary of another communicating path. It is sectional drawing corresponding to FIG. 3 which shows the outline | summary of another valve lifter supply oil path. It is a longitudinal cross-sectional view which shows the principal part of the conventional valve mechanism. It is the top view which fractured | ruptured a part which shows the principal part of FIG. It is an enlarged vertical view which shows the principal part.

Explanation of symbols

10 Cylinder head 21 Intake valve 22 Stem 23 Valve head 24 Applicator 25 Valve spring 26 Valve lifter 26a Cam sliding contact surface 26b Body 30 Bolt 31 Journal bearing 32 Cam cap 33 Bearing surface 33a Journal bearing surface 33b Cam cap bearing surface 33c Maximum shaft Load receiving portion 35 Cam shaft 36 Cam journal portion 36a Peripheral surface 38 Cam 39 Cam surface 39a Base portion 39b, 39d Ramp portion 39c Cam nose portion 41 Lubricating oil passage 41a Oil supply port 42 Valve lifter supply oil passage 42a Inlet port 42b Jet port 45 Communication passage 45a First opening 45b Second opening

Claims (4)

A camshaft in which a cam journal portion is rotatably supported on a bearing surface formed on a cylinder head, and a valve mechanism having a valve lifter that opens and closes an intake / exhaust valve by contact of the cam surface as the camshaft rotates. In the lubrication structure,
A lubricating oil passage having an oil filler opening on the bearing surface;
A valve lifter supply oil passage in which an inlet port is opened in the bearing surface and a jet port is opened toward the upper surface of the valve lifter;
A communication path formed in the cam journal portion having a first opening and a second opening that are opened in a peripheral surface of the cam journal portion, and
A valve lifter oil supply passage in which the first opening communicates with the oil supply port and the second opening communicates with the introduction port as the camshaft rotates according to the open / close state of the intake / exhaust valve, and the second opening provides oil supply. A lubrication structure for a valve operating mechanism, characterized in that a bearing surface oil supply passage is formed which communicates with the opening and the first opening opens toward the bearing surface.   The valve lifter oil supply passage in which the first opening communicates with the oil supply port and the second opening communicates with the introduction port is formed immediately before the cam surface starts to contact the valve lifter. The lubricating structure of the valve operating mechanism described.   The bearing surface oil supply passage in which the second opening communicates with the oil supply port and the first opening opens toward the bearing surface is formed at the maximum lift, and the first opening is the maximum axial load receiving portion of the bearing surface. The lubricating structure for a valve operating mechanism according to claim 1 or 2, wherein   4. The lubricating structure for a valve operating mechanism according to claim 3, wherein the maximum axial load receiving portion is a cam cap bearing surface of a cam cap coupled to a journal portion of a cylinder head.

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