JP4191622B2 - Engine valve gear - Google Patents

Description

  The present invention relates to a valve operating apparatus for an engine including a variable lift mechanism that continuously changes a lift amount of an engine valve.

In order to change the lift amount of the engine valve steplessly, one end of the push rod is fitted to the rocker arm that is linked and connected to the engine valve, and a link mechanism is provided between the other end of the push rod and the valve cam. A known valve operating device is already known from US Pat.
JP-A-8-74534

  However, in the valve operating apparatus of the engine disclosed in Patent Document 1, it is necessary to secure a relatively large space for arranging the link mechanism and the push rod between the valve operating cam and the rocker arm. Turn into. In addition, since the driving force from the valve cam is transmitted to the rocker arm via the link mechanism and the push rod, it is difficult to say that the follower of the rocker arm with respect to the valve cam, that is, the open / close operation followability of the engine valve is excellent.

  Therefore, the applicant of the present invention has one end portion of the first and second link arms rotatably connected to the rocker arm, and the other end portion of the first link arm is rotatably supported by the engine body. Japanese Patent Application No. 2002-196872 has already proposed a valve operating apparatus for an engine in which the other end is displaced by a driving means. According to this valve operating apparatus, the valve operating apparatus can be made compact. At the same time, the power from the valve cam can be directly transmitted to the rocker arm to ensure excellent followability to the valve cam.

  By the way, in order to absorb wear and temperature change and set the tappet clearance to “0”, a hydraulic tappet may be provided on the rocker arm, and when the rocker arm having the hydraulic tappet is applied to the above proposed valve operating apparatus, It is considered that the tappet is supplied with oil from a fixed support shaft that rotatably supports the first link arm to a fixed position of the engine body. The first link arm and the rocker arm are connected to the axis of the fixed support shaft. The oil is relatively displaced in an orthogonal plane, and it is difficult to transfer oil between the opposing surfaces of the two members that are relatively displaced without leakage.

  The present invention has been made in view of such circumstances, and after ensuring compactness and ensuring the followability of the opening / closing operation, the oil is reliably supplied from the fixed support shaft to the hydraulic tappet with a simple oil passage configuration. It is an object to provide a valve gear for an engine that can be supplied to the engine.

In order to achieve the above object, the present invention has a rocker arm having a cam abutting portion that abuts on a valve cam and interlocked with and coupled to an engine valve, and one end portion of the rocker arm that rotates via a first connecting shaft. A first link arm that is movably connected and has the other end rotatably supported via a fixed support shaft at a fixed position of the engine body, and one end rotated to the rocker arm via a second connection shaft. And a second link arm rotatably supported by a movable support shaft whose other end portion is displaceable, wherein the rocker arm has the first connection shaft as the first connection shaft. together with the position and and directly below that first connecting shaft directly below the valve operating cam second connecting shaft is arranged so as to be located, hydraulic tappet is provided in the rocker arm abuts before SL engine valve, wherein Rocker Said one end of the first link arm that Sessu sliding to the side of, said first rocker arm surrounds the connecting shaft cylindrical boss portion protruding on the opposite side is provided integrally, fitting the boss An oil passage forming member having a fitting hole to be fitted is in close contact with a side surface of the rocker arm at a position disengaged from a sliding contact portion of the one end portion of the first link arm with the rocker arm, and the oil passage forming member is attached to the rocker arm. but attached with a single bolt spaced from said boss portion, said first oil passage leading to the oil supply passage provided coaxially provided on the first link arm in the fixed support shaft Rutotomoni, the first oil second oil passage annular leading to road is formed between the boss portion and the first connection shaft of the first link arm, the third oil passage communicating with the second oil passage is provided in the oil passage forming member Rutotomoni , the third oil passage and the hydraulic The fourth oil passage connecting the pet, characterized in that provided in the rocker arm.

According to the present invention, it is possible to change the lift amount of the engine valve steplessly by displacing the movable support shaft steplessly, and the one end portions of the first and second link arms rotate to the rocker arm. Since it is directly connected as possible, the space for arranging both link arms can be reduced and the valve operating device can be made compact, and the power from the valve operating cam is directly transmitted to the cam contact portion of the rocker arm. Excellent followability to the valve cam can be ensured. The first link arm rotates about the axis of the fixed support shaft, and it is easy to let the oil supply path in the fixed support shaft communicate with the first oil path in the first link with less leakage. And forming a second oil passage between the boss portion at one end of the first link arm and the first connecting shaft with less leakage and leading to the first oil passage, and the axis of the first connecting shaft with respect to the boss portion. The third oil passage provided in the oil passage forming member that rotates relative to the circumference is passed through the second oil passage with less leakage, and the fourth oil passage provided in the rocker arm through the hydraulic tappet is connected to the rocker arm. It is easy to let the third oil passage of the oscillating oil passage forming member pass with less leakage, and oil can be reliably supplied from the fixed support shaft to the hydraulic tappet with a simple oil passage configuration. In addition, the oil in the second oil passage is the first Between Kuamu and first connecting shaft can be lubricated.

  1 to 4 show an embodiment of the present invention. FIG. 1 is a partial longitudinal sectional view of an engine, FIG. 2 is a sectional view taken along line 2-2 of FIG. 1, and FIG. FIG. 4 is a cross-sectional view taken along line 3 and FIG. 4 is a cross-sectional view taken along line 4-4 of FIG.

  First, in FIG. 1, a stem 7a of an intake valve 7 is slidably fitted to a cylinder head 6 of an engine body 5 of an engine so as to guide the opening and closing operation of a pair of intake valves 7 as engine valves. A guide cylinder 8 to be fitted is provided, and a valve for biasing the intake valve 7 in the valve closing direction is provided between the retainer 9 fixed to the upper portion of the stem 7a protruding from the guide cylinder 8 and the cylinder head 6. Springs 10 are provided.

  The valve operating device that opens and closes the intake valves 7 is provided with a rocker arm 13 that swings following the valve operating cam 11 and abuts against the engine valves 7 through hydraulic tappets 12. The cam 11 is provided on the camshaft 14. An upper holder 17 constituting a cam holder 15 together with the holder 16 is coupled to the lower holder 16 provided in the cylinder head 6 from above, and the cam shaft 14 is sandwiched between the upper and lower holders 16 and 17. Thus, the cam holder 15 is rotatably supported.

  This valve operating apparatus is provided with a variable lift mechanism 18 that can change the lift amount of the engine valve 6 in a stepless manner. The variable lift mechanism 18 includes a rocker arm 13 to which a hydraulic tappet 12 is mounted at one end. A first link arm 19 having one end rotatably connected to the end, a fixed support shaft 21 that rotatably supports the other end of the first link arm 19 at a fixed position of the engine body 5; A second link arm 20 disposed below the one link arm 19 and having one end rotatably connected to the other end of the rocker arm 13 and the other end of the second link arm 20 are rotatable. And a movable support shaft 22 to be supported.

  One end portion of the rocker arm 13 is provided with a valve connecting portion 13a for mounting a hydraulic tappet 12 that comes into contact with the upper end of the stem 7a of the pair of intake valves 7 from above. The other end portion of the rocker arm 13 is provided with a first support portion 13b and a second support portion 13c disposed below the first support portion 13b. The first and second support portions 13b are connected to each other. , 13c are formed in a substantially U-shape opened to the opposite side to the intake valves 7.

  A roller 23 that is in rolling contact with the valve cam 11 of the camshaft 14 is pivotally supported on the first support portion 13b of the rocker arm 13 via a first connecting shaft 24 and a roller bearing 25. The roller 23 is substantially U-shaped. It arrange | positions so that it may be pinched | interposed into the 1st support part 31b which is a shape.

  One end portion of the first link arm 19 is formed in a substantially U shape so as to sandwich the first support portion 13b of the rocker arm 13 from both sides, and the first link arm 19 is formed via a first connecting shaft 24 that pivotally supports the roller 23 on the rocker arm 13. 1 It is connected with the support part 13b so that rotation is possible. That is, the pivotable connection of the one end portion of the first link arm 19 to the rocker arm 13 and the axial support of the roller 23 to the rocker arm 13 are achieved by the common first connection shaft 24, thereby It is possible to reduce the number of points and contribute to making the valve gear compact.

  On both sides of the other end of the first link arm 19, support bosses 16 a projecting toward the first link arm 19 are respectively projected from the lower holders 16 of the cam holders 15, and pass through the support bosses 16 a. In this way, the other end portion of the first link arm 19 is rotatably supported by the fixed support shaft 21 supported by the lower holder 16..., And the first link arm in the direction along the axis of the fixed support shaft 21. The movement of 19 is regulated by both support bosses 16a.

  One end portion of the second link arm 20 disposed below the first link arm 19 is disposed so as to be sandwiched between the second support portions 13c of the rocker arm 13, and the second support portion 13c is interposed via the second connecting shaft 26. To be pivotally connected to each other.

  In such a variable lift mechanism 18, the movable support shaft 22 is driven to move steplessly by a driving means (not shown), and the lift amount of the intake valves 7. It will change steplessly.

  3 and 4, a bottomed mounting hole 27 is formed on both sides of the valve connecting portion 13a of the rocker arm 13 with its upper end closed, and a through hole 28 is formed in the central portion of the closed end of the mounting hole 27. The closed end inner surface around the through-holes 28 functions as an annular restricting portion 29.

  The hydraulic tappet 12 has a bottomed cylindrical shape with its lower end closed and is slidably fitted into the mounting hole 27, and is mounted so as to cover the lower end closing portion of the plunger 30. A cap-shaped tip 31 that is partly slidably fitted to the lower part of the first member, a cylindrical member 32 that is slidably fitted to the plunger 30, and a compaction between the plunger 30 and the cylindrical member 32. Return spring 33 and check valve 34.

  Near the lower end of the cylindrical member 32, a partition wall 36 that forms a hydraulic chamber 35 between the lower end closed portion of the plunger 30 and an oil reservoir chamber 37 that is formed in the cylindrical member 32 above the partition wall 36. The return spring 33 is provided so as to be separated from the hydraulic chamber 35, and the return spring 33 is provided between the lower closed end of the plunger 30 and the partition wall 36.

  The check valve 34 has a spherical valve body 39 that can close a valve hole 38 formed in the center of the partition wall 36 from the hydraulic chamber 35 side so that the oil reservoir chamber 37 and the hydraulic chamber 35 can communicate with each other. However, the return spring 33 is pressed against the partition wall 36 side and is stored in a floating manner in a cage 40 accommodated in the hydraulic chamber 36 so that the cylindrical member 32 increases the volume of the hydraulic chamber 35. When the valve 30 is moved upward relative to the plunger 30, the check valve 34 is opened to allow oil return from the hydraulic chamber 35 to the oil reservoir chamber 37.

  Such a hydraulic tappet 12 is received by a receiving member 41 slidably fitted into the mounting hole 27 inward of the hydraulic tappet 12, and the receiving member 41 is the cylindrical member 32. A bottomed cylindrical portion 41a that is slidably fitted into the mounting hole 27 so that the upper end of the bottom end is in contact with the closed end, and the bottomed cylindrical portion 41a that movably penetrates the through hole 28. And a shaft portion 41b that is provided coaxially and integrally with the central portion.

  An annular passage 42 is formed in the mounting hole 27 between the bottomed cylindrical portion 41 a of the receiving member 41 and the upper end of the plunger 30, and a plurality of communication holes through which the annular passage 42 communicates with the oil sump chamber 37. 43... Are provided on the cylindrical member 32.

  In the receiving member 41, an adjustment screw 44 is brought into contact with the upper end of the shaft portion 41 b discharged upward from the through hole 28 when the intake valve 7 is closed. In the closed state of the intake valve 7, the restricting portion 29 and the receiving member 41 provided at the closed end of the mounting hole 27 so as to face the bottomed cylindrical portion 41 a of the receiving member 41 from the side opposite to the hydraulic tappet 12. The adjustment screw 44 is screwed into the engine body 5 such that the advance / retreat position can be adjusted by adjusting the distance between the bottomed cylindrical portion 41a and the bottomed cylindrical portion 41a.

  In addition, a screw holding portion 45 is provided on a lower holder 16 of a cam holder 15 provided on the engine body 5 by rotatably supporting the camshaft 14, and the adjustment screw 4 is screwed onto the screw holding portion 45.

In order to supply oil to the hydraulic tappets 12..., An oil supply path 46 leading to an oil supply source (not shown) is provided in the fixed support shaft 21. A cylindrical boss portion 47 surrounding the connecting shaft 24 and protruding to the opposite side of the rocker arm 13 is integrally provided, and an oil passage forming member 48 is separated from the boss portion 47 on the rocker arm 13 . It is attached with a bolt 49.

  The oil passage forming member 48 is attached to the rocker arm 13 so as to be in close contact with the side surface of the rocker arm 13 at a position disengaged from the sliding contact portion of the one end portion of the first link arm 19 with the rocker arm 13. The path forming member 48 is provided with a fitting hole 50 for fitting the boss portion 47, and a protruding portion 51 protruding so as to be oil-tightly fitted to the side surface of the rocker arm 13.

  The first link arm 19 is provided with a first oil passage 52 that communicates with the oil supply passage 46 in the fixed support shaft 21, and an annular second oil passage 53 that communicates with the first oil passage 52 is provided on the first link arm 19. It is formed between the boss portion 47 and the first connecting shaft 24. Further, a third oil passage 54 that allows one end to pass through the second oil passage 53 is provided in the oil passage forming member 48 so that the other end is disposed in the projection 51, and the third oil passage 54 and the hydraulic tappet 12. A fourth oil passage 55 connecting the annular passages 42 is provided in the rocker arm 13.

  Next, the operation of this embodiment will be described. The lift amount of the intake valves 7 can be changed steplessly by displacing the movable support shaft 22 of the variable lift mechanism 18 steplessly. One end of each of the second link arms 19 and 20 is directly connected to the rocker arm 13 so as to be rotatable, so that the space for arranging both link arms 19 and 20 can be reduced and the valve operating apparatus can be made compact. Since the power from the valve cam 11 is directly transmitted to the roller 23 of the rocker arm 13, excellent followability to the valve cam 11 can be ensured.

  The rocker arm 13 is in contact with the intake valves 7 through the hydraulic tappets 12. The receiving member 41 for receiving the hydraulic tappet 12 is slidably fitted to the rocker arm 13. A regulating portion 29 that is opposed to the receiving member 41 from the opposite side is provided, and an adjusting screw 44 that adjusts the distance between the regulating portion 29 and the receiving member 41 when the intake valves 7 are closed closes the intake valve 7. The valve is screwed into the engine body 5 so that the advance / retreat position can be adjusted so as to contact the receiving member 41 during the valve operation.

  Thus, in a state where the intake valve 7 is closed and there is a space between the restricting portion 29 of the rocker arm 13 and the receiving member 41, the restricting portion 29 receives after the rocker arm 13 starts swinging in the valve opening direction. Until the contact with the member 41, no force in the valve opening direction acts on the intake valve 7 from the hydraulic tappet 12. Therefore, the advance / retreat position of the adjustment screw 44 that contacts the receiving member 41 in the closed state of the intake valve 7 is determined. By adjusting the distance between the restricting portion 29 and the receiving member 41, the intake valve 7 can be prevented from being varied in the lift amount of the intake valve 7 even if there is a manufacturing error or assembly error of each part of the valve operating device. The lift amount can be adjusted accurately and easily. As a result, even when the lift amount of the intake valve 7 becomes minute due to the variable lift mechanism 18, it is possible to achieve the minute lift amount with high accuracy, which is advantageous for the valve gear having the variable lift mechanism 18.

  In addition, even when the rocker arm 13 swings by the distance between the restricting portion 29 and the receiving member 41 in response to the dynamic swing of the camshaft 14, the intake valve 7 is pushed up by the hydraulic tappet 12. In addition, it is possible to prevent the intake valve 7 from being pushed up by the hydraulic tappet 12 without requiring complicated work and manufacturing management.

  Further, since the cam holder 15 provided on the engine body 11 by rotatably supporting the camshaft 14 is provided with the screw holding portion 45 for screwing the adjustment screw 44, the support rigidity of the adjustment screw 44 can be increased.

  By the way, although it is necessary to supply oil to the hydraulic tappet 12, the first link arm 19 is slidably in contact with the side surface of the rocker arm 13 and is rotatably connected to the rocker arm 13 via the first connecting shaft 24. An oil passage having a fitting hole 50 in which a cylindrical boss portion 47 surrounding the first connecting shaft 24 and projecting to the opposite side of the rocker arm 13 is integrally provided at one end of the boss portion 47. The forming member 48 is attached to the rocker arm 13 so as to be in close contact with the side surface of the rocker arm 13 at a position away from the sliding contact portion of the one end portion of the first link arm 19 with the rocker arm 13. A first oil passage 52 communicating with the oil supply passage 46 provided is provided in the first link arm 19, and an annular second oil passage 53 communicating with the first oil passage 52 is provided in the first link arm 19. A third oil passage 54 formed between the boss portion 47 and the first connecting shaft 24 and leading to the second oil passage 53 is provided in the oil passage forming member 48, and the third oil passage 54 and the hydraulic tappet 12 are connected to each other. Four oil passages 55 are provided in the rocker arm 13.

  According to such an oil path configuration, the first link arm 19 rotates around the axis of the fixed support shaft 21, and the oil supply path 46 in the fixed support shaft 21 is connected to the first link arm 19 in the first link arm 19. It is easy to let the first oil passage 52 pass through with less leakage, and the second oil that leads to the first oil passage 52 with less leakage between the boss portion 47 of the first link arm 19 and the first connecting shaft 24. Forming the passage 53, the third oil passage 54 provided in the oil passage forming member 48 that rotates relative to the boss portion 47 around the axis of the first connecting shaft 24 is less leaked to the second oil passage 53. And the fourth oil passage 55 provided in the rocker arm 13 through the hydraulic tappet 12 is passed through the third oil passage 54 of the oil passage forming member 48 that swings together with the rocker arm 13 with less leakage. It is also easy to The oil can be reliably supplied from the fixed support shaft 21 to the hydraulic tappet 12 with a single oil passage configuration, and the oil in the second oil passage 53 is lubricated between the first link arm 19 and the first connecting shaft 24. can do.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the present invention described in the claims. It is.

It is a partial longitudinal cross-sectional view of an engine. FIG. 2 is a sectional view taken along line 2-2 of FIG. FIG. 3 is a sectional view taken along line 3-3 in FIG. 2. FIG. 4 is a cross-sectional view taken along line 4-4 of FIG.

Explanation of symbols

5 ... Engine body 7 ... Intake valve 11 as engine valve ... Valve cam 12 ... Hydraulic tappet 13 ... Rocker arm 19 ... First link arm 20 ... Second link arm 21 ... fixed support shaft 23 ... roller 24 ... first connecting shaft as the cam abutment portion
26 ... 2nd connecting shaft 46 ... Oil supply path 47 ... Boss part 48 ... Oil path formation member
49 ... bolt 50 ... fitting hole 52 ... first oil passage 53 ... second oil passage 54 ... third oil passage 55 ... fourth oil passage

Claims (1)

The rocker arm (13) has a cam contact portion (23) that contacts the valve cam (11) and is linked and connected to the engine valve (7), and one end of the rocker arm (13) is connected to the first connecting shaft ( 24) and a first link arm (19) that is pivotally connected via a fixed support shaft (21) to the fixed position of the engine body (5) and pivotally connected to the other end of the engine body (5). The first end is rotatably connected to the rocker arm (13) via the second connecting shaft (26), and the other end is rotatably supported by the movable support shaft (22). In an engine valve gear comprising two link arms (20),
In the rocker arm (13), the first connecting shaft (24) is positioned immediately below the valve cam (11), and the second connecting shaft (26) is positioned directly below the first connecting shaft (24). together are arranged to, in contact with the hydraulic tappet (12) is provided on the rocker arm (13) is preceded SL engine valve (7),
To the one end of the rocker arm first link arm that Sessu sliding to the side of (13) (19), a cylindrical shape protruding on the opposite side of the rocker arm (13) surrounds the first connecting shaft (24) The boss part (47) is provided integrally,
From sliding contact portion of the oil passage forming member having a fitting hole (50) allowed to fit the boss portion (47) (48), to the rocker arm of the end portion of the first link arm (19) (13) The oil passage forming member (48) is attached to the rocker arm (13) with a single bolt (49) spaced from the boss portion (47) while being in close contact with the side surface of the rocker arm (13) at the disengaged position. ,
Oil supply passage provided coaxially on the fixed support shaft (21) in the first oil passage leading to (46) (52) is provided on the first link arm (19) Rutotomoni, the first oil passage that (52) An annular second oil passage (53) communicating with the first link arm (19) is formed between the boss portion (47) and the first connecting shaft (24),
The second oil passage third oil passage leading to (53) (54) is provided in the oil passage forming member (48) Rutotomoni, fourth connecting the its third oil passage (54) and hydraulic tappets (12) An oil valve (55) is provided in the rocker arm (13).

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