JP2007170304A - Variable valve gear for engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a variable valve gear providing a large lift difference or a high lift amount with compact and simple structure, and efficiently regulating rotation of a slide pin member. <P>SOLUTION: In the variable valve gear 1 for an engine, a tappet unit 8 is disposed between a cam 6 and a valve stem 12. The tappet unit 8 comprises: a tappet main body 36; a movable tappet 30 movable relatively to the tappet main body; a slide pin member 40 disposed to the tappet main body and movable between two positions; a guide hole 60a for the slide pin member and its opening part 60b; a projection part 30g formed to the movable tappet and projecting toward the opening part; and a spacer member 42 fixed to the slide pin member in such a manner that the spacer member is opposed to the projection part at one of the two positions, and is not opposed to the projection part at the other position. An outer edge part 60e of the opening part is abutted to guide the movement of the spacer member and restrict the rotation of the slide pin member. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a variable valve operating apparatus for an engine, and more particularly to a variable valve operating apparatus for an engine capable of switching valve lift characteristics.

  Conventionally, a direct type valve operating device that directly drives a valve (engine valve) with a cam via a tappet is known. As such a valve operating apparatus, a variable valve operating apparatus capable of changing the valve lift characteristics by changing the valve lift amount according to the operating state or switching the presence or absence of the lift to stop the driving of the valve. It has been known.

  As a variable valve operating apparatus that changes the lift amount, Patent Document 1 discloses a variable valve operating apparatus that includes a side tappet and a center tappet, and into which lock pins made of three pin members are inserted. ing. In this variable valve operating apparatus, the lock pin is supported by the spring, and the switching control valve is operated to supply or discharge the hydraulic pressure to the hydraulic operating chamber communicated with the lock pin to resist the elastic force of the spring. The lock pin is moved. With such a mechanism, for example, during high-speed operation, high-pressure hydraulic oil is supplied, and the lock pin is moved to the lock position across both the side tappet and the center tappet to integrate those tappets. The center cam for high speed pushes the center tappet to lift the valve with a high lift amount. On the other hand, during low-speed operation, the lock pressure of the hydraulic oil is reduced to release the lock pin, so that the center tappet moves relative to the side tappet. Press to lift with low lift.

  On the other hand, as a variable valve operating apparatus capable of pausing the lift, Patent Document 2 includes a slide pin holder provided inside a valve lifter (tuppet) and a slide pin that moves against the spring force hydraulically. There is disclosed a variable valve apparatus in which a flat portion and a hole are formed in a part of the slide pin. In this variable valve operating apparatus, the position of the slide pin is switched between two positions, and by this switching, the valve stem end abuts against the flat portion of the slide pin and the valve stem is lifted via the valve lifter, or the valve The stem end part enters the hole of the slide pin so that the valve stem is not lifted.

JP 2003-106122 A JP 2003-027908 A

  Here, according to the variable valve operating apparatus disclosed in Patent Document 1 described above, the high lift amount and the low lift amount can be switched by hydraulic control, but such a lock requiring a plurality of pin members is required. The pin type has a relatively complicated structure, which is disadvantageous in terms of durability and manufacturing cost. Therefore, a simpler structure is desired.

  On the other hand, the variable valve operating apparatus disclosed in Patent Document 2 described above has a relatively simple structure. However, as described in Patent Document 2, a guide pin is required to restrict inadvertent rotation of the slide pin. In addition, in the structure in which such a slide pin is simply cut out in a concave shape to form a flat surface portion and a hole portion is formed, a valve resting type that requires a higher lift amount or a difference between a high lift and a low lift is eliminated. In order to make the lift amount change type that is required to be larger, it is necessary to increase the pin diameter or to form a large space inside the tappet so that the valve stem does not interfere with the tappet. However, in such a case, the entire tappet becomes large, which is not preferable.

  Therefore, the present invention has been made to solve the above-described problems of the prior art, and it is possible to obtain a large lift difference in the lift amount change type or a high lift amount in the valve suspension type with a compact and simple configuration. Another object of the present invention is to provide a variable valve operating apparatus that can efficiently control the rotation of a slide pin member.

In order to achieve the above object, the present invention is a variable valve operating device for an engine capable of switching valve lift characteristics, and is provided between a valve operating cam, a valve stem, and a valve operating cam and a valve stem. A tappet unit capable of switching valve lift characteristics, and the tappet unit is connected to the valve stem, and is movable relative to the tappet body so as to be relatively movable in the axial direction of the valve stem. A tappet, a slide pin member with a circular cross-section that is arranged on the tappet body and is movable between two positions in a direction perpendicular to the axial direction of the valve stem, and formed on the tappet body, the slide pin member is slidable The guide hole to be accommodated and the guide part having an opening part of the guide hole opened to the movable tappet side, and the opening formed in the movable tappet And a spacer that is fixed to the slide pin member at a position that faces the protrusion when the slide pin member is in one of the two positions and does not face when the slide pin member is at the other position. And the opening of the guide part opens at least in a range in which the spacer member moves, the spacer member has an enlarged part protruding from the slide pin member in the radial direction of the slide pin member in a top view, At least a part of the outer edge portion of the opening of the guide portion is formed as a posture determining portion that abuts on the enlarged portion of the spacer member to guide the movement of the spacer member and suppress the rotation of the slide pin member. It is said.
In the present invention configured as described above, the valve lift characteristics can be effectively switched by the protrusion, the spacer member, and the slide pin member while making the tappet unit compact as a whole. In particular, the lift amount can be effectively changed by the spacer member. Further, since the spacer member also serves to determine the posture of the slide pin member by cooperating with at least a part of the outer edge portion of the guide portion, the tappet unit can be formed more compactly. Furthermore, since the spacer member effectively supports the load received from the movable tappet via the protrusion at the outer edge portion of the guide portion, the slide pin member maintains its posture and the load resistance while keeping the slide pin member smooth. The strength can be satisfied with a simple configuration. Therefore, a large lift difference in the lift amount change type or a high lift amount in the valve rest type can be obtained with a compact and simple configuration, and the rotation regulation of the slide pin member can be efficiently performed.

In the present invention, preferably, the slide pin member is formed with a space portion on one side of the spacer member in the axial direction, and the space pin is located at the other position of the two positions of the slide pin member. Sometimes it is formed in a size that can accept the protrusion of the movable tappet.
In the present invention configured as described above, a large lift difference in the lift amount change type can be obtained by the space portion formed so as to be able to receive the protrusion of the movable tappet.

In the present invention, it is preferable that the tappet body is composed of two side tappets arranged at intervals in the cam shaft direction of the valve cam and a connecting portion that connects these side tappets. It consists of a center tappet provided between two side tappets and slidably guided by the side tappet. The valve cam is composed of two low lift cams for two side tappets and a high lift cam for center tappets Have.
In this invention comprised in this way, a suitable structure can be obtained as a variable valve apparatus of the lift amount change type which switches the magnitude of a lift amount.

In the present invention, preferably, a connecting portion is provided in a lower portion of the two side tappets, and a guide portion and a slide pin member are provided in the connecting portion.
In the present invention configured as described above, the tappet unit having the side tappet and the center tappet can be formed compactly as a whole.

In the present invention, it is preferable that the slide pin member has a concave portion formed by notching the slide pin member in a side view, and the space portion of the slide pin member is a space formed by the concave portion. Of at least one part.
In the present invention configured as described above, it is possible to reliably eliminate the interference between the projecting portion and the slide pin and obtain a larger lift difference. For example, even if a reinforcing rib that reinforces the center tappet is formed on the side of the protrusion, it is also possible to receive such a reinforcing rib, and a larger lift difference can be obtained.

In the present invention, preferably, the slide pin member has a hole formed below the concave portion, and the space portion of the slide pin member is formed in at least one portion of the space formed by the concave portion and the hole portion. Has been.
In the present invention configured as described above, a large lift difference can be obtained more reliably.

In the present invention, it is preferable that the concave portion has a flat bottom surface, and the spacer member is fixed to the bottom surface formed flat at a part of the concave portion.
In the present invention configured as described above, since the bottom surface of the concave portion is formed flat, the spacer member can be easily provided. Further, since the concave portion serves as both the attachment portion of the spacer member and the space portion formation, the structure can be simplified.

In the present invention, preferably, the two side tappets are provided with rollers in contact with the two low lift cams in the upper portion thereof.
In the present invention configured as described above, sliding resistance can be reduced while keeping the tappet unit compact by effectively utilizing the upper portion of the side tappet.

In the present invention, preferably, the guide hole formed in the tappet body is provided with a return spring on one end side of the slide pin member and a hydraulic chamber on the other end side.
In the present invention configured as described above, the slide pin member can be moved quickly and easily by switching the hydraulic pressure, and as a result, the lift amount can be easily changed or the lift can be stopped.

In the present invention, preferably, a gap is formed between the enlarged portion of the spacer member and the posture determining portion so that the spacer member can swing a predetermined amount around the axis of the slide pin member.
In the present invention configured as described above, even if the movable tappet that has received the sliding contact load by the valve cam is slightly inclined due to the gap for maintaining the sliding property between the movable tappet and the tappet body, the spacer Since the member is tilted accordingly, the protrusion and the spacer can be effectively brought into contact with each other. For example, when the lower surface of the protrusion and the upper surface of the spacer are respectively formed on a flat surface, it is possible to reliably bring these surfaces into surface contact. Therefore, uneven wear of the protrusion and the spacer member can be suppressed.

In the present invention, it is preferable that the tappet body is composed of two side tappets arranged at intervals in the cam shaft direction of the valve cam and a connecting portion that connects these side tappets. The center tappet is provided between the two side tappets and is slidably guided by the side tappet. The valve cam is constituted only by a center tappet cam.
In this invention comprised in this way, a suitable structure can be obtained as a lift stop type variable valve operating apparatus which switches the stop and operation | movement of a lift.

In order to achieve the above object, the present invention provides a variable valve operating device for an engine capable of switching valve lift characteristics, and includes a valve operating cam, a valve stem, and a valve operating cam and a valve stem. A tappet unit that can switch valve lift characteristics, and this tappet unit connects two side tappets that are spaced apart from each other in the camshaft direction of the valve cam, and connects these side tappets. It is provided between the two side tappets and the tappet body connected to the valve stem. The side tappet is slidably guided so as to be movable relative to the tappet body in the axial direction of the valve stem. A center tappet that is disposed on the tappet body and is movable between two positions in a direction perpendicular to the axial direction of the valve stem. A circular slide pin member, a guide hole that is formed in the tappet body and slidably accommodates the slide pin member, and a guide portion having an opening in which a part of the guide hole is opened to the center tappet side, and a center tappet And a projecting part projecting toward the opening, and a slide pin member that faces the projecting part when the slide pin member is in one of the two positions and does not oppose when it is in the other position. A spacer member fixed to the opening, and the opening of the guide portion opens at least within a range in which the spacer member moves, and the spacer member expands from the slide pin member in the radial direction of the slide pin member in a top view. At least a part of the outer edge of the opening of the guide portion abuts on the enlarged portion of the spacer member to guide the movement of the spacer member and the slide pin member Formed rolling for suppressing attitude deciding part, the valve operating cam, and two low-lift cam for the two side tappet is characterized by having a high lift cam for center tappet.
In the present invention configured as described above, a large lift difference in the lift amount change type or a high lift amount in the valve rest type can be obtained with a compact and simple configuration and the rotation regulation of the slide pin member is efficiently performed. I can do it. In addition, it is possible to obtain a configuration suitable as a variable lift device of a lift amount changing type that switches the lift amount.

  According to the variable valve operating apparatus of the present invention, a large lift difference in the lift amount change type or a high lift amount in the valve rest type can be obtained with a compact and simple configuration, and the rotation regulation of the slide pin member is efficiently performed. I can do it.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
First, the main configuration of the variable valve operating system for an engine according to the first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a view showing a structure of an upper part of an engine provided with a variable valve operating apparatus according to a first embodiment of the present invention, FIG. 2 is a perspective view showing a tappet unit, and FIG. 3 is an enlarged view of the tappet unit. FIG.
First, as shown in FIG. 1, the engine 1 according to the present embodiment includes a valve unit 4 provided in a cylinder head 2, a camshaft 6 extending in the front-rear direction of the engine, and between the valve unit 4 and the camshaft 6. The tappet unit 8 is provided.

The valve unit 4 includes a valve stem 12 guided by a guide portion 10 and slidable in the vertical direction, a valve 16 provided at the lower end portion of the valve stem 12 for opening and closing the combustion chamber of the intake port 14, and the valve stem 12. The valve cotter 18 and the shim 20 provided at the upper end of the valve 16 and the valve spring 22 for urging the valve 16 to the closed position are provided.
The camshaft 6 is formed with a valve cam 24 for driving the tappet unit 8. The cam 24 has two low lift cams (side cams) 24a having a cam profile with a small lift amount and a high lift cam (center cam) 24b having a cam profile with a large lift amount. The low lift side cam 24a is for the engine low rotation range, and the high lift center cam 24b is for the engine high rotation range.

The tappet unit 8 is provided in a substantially cylindrical tappet guide wall portion 26 formed in the cylinder head of the engine, and is guided by the tappet guide wall portion 26 so as to be slidable in the vertical direction.
As shown in FIGS. 1 to 3, the tappet unit 8 includes a center tappet 30 and two side tappets 32 arranged on both sides of the center tappet 30. The two side tappets 32 are spaced apart from each other in the cam shaft direction of the camshaft 6 (denoted by symbol C in FIG. 2), and are connected to each other by a connecting portion 34 at the lower portion of the side tappets 32. Has been. These two side tappets 32 and the connecting portion 34 are integrally molded. Hereinafter, this integrally molded member is referred to as a side tappet member 36. The connecting portion 34 is connected to the valve stem 12 via the shim 20, and the amount of movement of the side tappet member 36 in the vertical direction becomes the lift amount of the valve 16 as it is.

  As shown in FIGS. 1 and 3, the tappet unit 8 further supports a slide pin member 40, a spacer member 42, a return spring 44 (not shown in FIG. 3) for the slide pin member 40, and the return spring 44. It has components such as a snap ring 46.

Next, the structure of the center tappet 30 and the side tappet member 36 will be described with reference to FIGS. 4 is a perspective view showing the side tappet member, FIG. 5 is a perspective view showing the center tappet, FIG. 6 is a bottom view of the center tappet as viewed from below, and FIG. It is sectional drawing of the tappet unit seen along the VII-VII line.
As shown in FIGS. 2 to 5, the center tappet 30 has a substantially U-shape as a whole, and a slide contact surface 30a with which the center cam 24b slides is formed on the upper surface portion. A slidable contact surface 32 a with which the side cam 24 a is slidably contacted is formed on the upper surface portion of the side tappet 32. These sliding contact surfaces 30 a and 32 a both extend in a direction orthogonal to the cam shaft direction C.

  The side tappet member 36 moves in the vertical direction (the axial direction of the valve stem 12) as the outer peripheral side surface 32b (see FIGS. 2 and 4) of the side tappet 32 is guided by the tappet guide wall 26, and the center tappet 30 The outer peripheral side surface 30b (see FIGS. 2, 5, and 6) is guided by the tappet guide wall portion 26 so as to move in the vertical direction (the axial direction of the valve stem 12). As shown in FIGS. 2 and 5, the center tappet 30 is formed with guide portions 30c that protrude in the cam shaft direction C and extend in the vertical direction at the four corners when viewed from above, and these guide portions 30c. However, the center tappet 30 can be moved relative to the side tappet 32 in the vertical direction by being guided by the guide surface 32 c (see FIG. 4) of the side tappet 32. The center tappet 30 is also guided by the inner side surface 32d (see FIG. 4) of the side tappet 32 in the initial stage of the relative movement.

  As shown in FIGS. 4 and 7, two spring receiving portions 34 a extending in a direction orthogonal to the extending direction of the connecting portion 34 are integrally formed on the connecting portion 34 of the side tappet member 36. As shown in FIG. 7, two return springs 50 for the center tappet 30 are provided between the spring receiving portions 34 a and the upper surface portion 30 d of the center tappet 30. By this return spring 50, when the center tappet 30 is not pushed by the center cam 24b, the sliding contact surface 30a and the sliding contact surface 32a as shown in FIG. 2 or FIG. It is biased to the normal position.

  As shown in FIGS. 5 and 6, reinforcing ribs 30 e and 30 f for securing the rigidity of the substantially U-shaped center tappet 30 are formed in the upper portion of the center tappet 30. The reinforcing rib 30e also serves as a holding portion for the return spring 50.

  Further, as shown in FIGS. 3, 5 and 7, the center tappet 30 is formed with a protrusion 30g protruding downward from the reinforcing rib 30f. The reinforcing rib 30f also serves to ensure the rigidity of the convex portion 30g. As shown in FIG. 6, the protrusion 30g has a substantially circular cross section.

Next, the structure of the connecting portion 34 and the arrangement of the slide pin member 40 will be described with reference to FIGS. 3, 4, 7 to 9. FIG. 8 is a cross-sectional view of the tappet unit taken along line VIII-VIII in FIG. 2, and FIG. 9 is a cross-sectional view of the tappet unit taken along line IX-IX in FIG.
First, as shown in FIG. 3, a slide pin member 40 having a circular cross section is provided at the connecting portion 34 of the side tappet member 36. As shown in FIG. 4, the connecting portion 34 has a guide portion 60 that guides the movement of the slide pin member 40 in the axial direction. The guide portion 60 is formed with a guide hole 60a having a circular cross section for slidably receiving the slide pin member 40 and an opening 60b for opening a part of the guide hole. As shown mainly in FIGS. 8 and 9, the guide hole 60 a extends in a direction substantially coinciding with the direction in which the cam shaft C extends, and the axial direction of the valve stem 12 (see FIG. 1) and the moving direction of the center tappet 30. It extends in the direction orthogonal to. The axis of the slide pin member 40 also extends in such a direction and moves through the guide hole 60a.

  As shown in FIGS. 4, 7, and 8, the opening 60 b is formed to open to the upper center tappet 30 side. And the protrusion 30g formed in the center tappet 30 mentioned above protrudes toward this opening part 60b, and the spacer member 42 mentioned later is arrange | positioned so that the inside of this opening part 30g is movable.

  As shown in FIG. 8, a return spring 44 is disposed on one end side of the slide pin member 40 in the guide hole 60 a. One portion of the return spring 44 is disposed in a cylindrical portion 40 a formed on the slide pin member 40, and the other end portion is supported by a snap ring 46. The slide pin member 40 is urged by the return spring 44 to the first position as shown in FIG. 8 (see FIG. 11A). In this first position, the slide pin member 40 is positioned such that space portions 40d and 40e of the slide pin member 40 described later face the protrusion 30g of the center tappet 30.

  On the other hand, a hydraulic chamber 60 c is formed in the guide hole 60 a on the other end side of the slide pin member 40. When high pressure hydraulic oil is supplied to the hydraulic working chamber 60c via the oil passage 26a (see FIG. 1), the slide pin member 40 moves overcoming the urging force of the return spring 44. . And it moves to a 2nd position (refer FIG.11 (b)) as shown in FIG. In this second position, the slide pin member 40 is positioned so that the spacer member 42 of the slide pin member 40 faces the protrusion 30g of the center tappet 30.

Next, the structure of the slide pin member 40 and the spacer member 42 will be described with reference to FIGS. 3, 7, 8 to 10. FIG. 10 is a partially enlarged view showing a portion where the spacer member is provided in FIG. 7 in an enlarged manner.
As shown in FIGS. 3 and 8, the slide pin member 40 is formed with a concave portion 40b in which the slide pin member 40 is cut out in a concave shape in a side view, and a flat plane portion 40c is formed on the bottom surface thereof. ing. A spacer member 42 is disposed in a part of the concave portion 40b, and the spacer member 42 is fixed to the slide pin member 40 by screws. A part of the space formed by the concave portion 40b is occupied by the spacer member 42, and the remaining portion 40d adjacent to the spacer member 42 is left in the space. The slide pin member 40 is formed with a hole 40e having a circular cross section that penetrates vertically below the space portion 40d. Thus, a space is formed by the space portion 40d and the hole portion 40e, and this space has a size that can sufficiently receive the protruding portion 30g of the center tappet 30. Note that the hole 40e may not be provided as long as a necessary lift amount can be secured.

  Further, since the concave portion 40b is formed by cutting out into a concave shape, not only the protrusion 30g but also the surrounding reinforcing rib 30f can be received in the space portion 40d. Further, the flat surface portion 40c is formed so that the spacer member 42 can be easily fixed. It should be noted that the slide pin member 40 may be provided with a hole that penetrates up and down, or a bottomed hole that is large enough to receive the protrusion 30g, without providing the concave portion 40b. Further, as shown in FIG. 8, a concave portion 60d is formed in a lower portion of the guide portion 60 at a position facing the above-described protrusion 30g, and the concave portion 60d is also sized to receive the protrusion 30g. Is formed.

  As shown in FIGS. 3 and 8, the upper surface of the spacer member 42 is formed flat. On the other hand, the lower surface of the protrusion 30 g described above is formed flat so as to face the upper surface of the spacer member 42. These surfaces are substantially parallel to each other, and come into surface contact when the protrusion 30g contacts the spacer member 42 as will be described later.

  Further, as shown in FIG. 7, the spacer member 42 has a width larger than the diameter of the slide pin member 40, and in the width direction (the radial direction of the slide pin member 40), an enlarged portion that projects from the slide pin member 40 42a. On the other hand, the wall portion (outer edge portion) 60e of the opening portion 60b has almost the same height as the lower surface of the enlarged portion 42a in the range where the spacer member 42 moves, and the lower surface of the enlarged portion 42a and the upper surface of the wall portion 60e. Are in contact with each other. By such contact, the wall portion 60e is configured as a posture determining portion that guides the movement of the spacer member 42 and suppresses the rotation of the slide pin member 40 about the axis.

  A slight gap is formed between the center tappet 30 and the tappet wall portion 26 and the side tappet 32 to ensure the slidability of the center tappet 30. A sliding load by the center cam 24b is applied to the center tappet 30 in the sliding direction S as shown in FIG. Therefore, when the center tappet 30 receives a sliding load, the center tappet 30 may be slightly inclined in the sliding direction S. As the center tappet 30 is inclined, the protrusion 30g is also inclined, and the contact state between the protrusion 30g and the spacer member 42 is changed.

  On the other hand, in this embodiment, as shown in FIG. 10, a gap G is formed between the lower surface of the enlarged portion 42a and the upper surface of the wall portion 60e, and the slide pin member 40 and the spacer member 42 are It can be slightly swung in the circumferential direction or the width direction. Therefore, due to the inclination of the center tappet 30, even if the lower surface of the protrusion 30g is not parallel to the upper surface of the spacer member 42, the spacer member 42 swings and the protrusion 30g The lower surface and the upper surface of the spacer member 42 are in surface contact.

Next, the main operation of the present embodiment will be described mainly with reference to FIG.
FIG. 11 is a cross-sectional view similar to FIG. 8 for explaining the operation of the variable valve operating system for an engine according to the first embodiment of the present invention. FIG. 11 (a) shows the slide pin in the first position. FIG. 11B shows the case where the center tappet can be swung freely. FIG. 11B shows that the slide pin is in the second position and the center tappet can abut against the spacer member to push the side tappet member. Shows the case.

First, as shown in FIG. 11A, when the hydraulic oil in the hydraulic working chamber 60c is depressurized, the slide pin member 40 is positioned at the first position. In the first position, as described above, the space portions 40d and 40e of the slide pin member 40 face the protrusion 30g of the center tappet 30. Therefore, when the center tappet 30 is pushed by the high lift amount center cam 24b and moves relative to the side tappet member 36, the protrusion 30g is received in the space portions 40d and 40e and the recess 60d. As a result, the center tappet 30 is in an idling state where it does not come into contact with the side tappet member 36, and the high lift amount of the center cam 24b is not reflected in the lift amount of the valve 16.
On the other hand, since the side tappet 32 is pushed by the low lift side cam 24 a, the valve 16 can be lifted with a low lift amount via the valve stem 12 connected to the side tappet member 36.

Next, as shown in FIG. 11B, when the hydraulic oil in the hydraulic working chamber 60c is pressurized, the slide pin member 40 is positioned at the second position. In the second position, as described above, the spacer member 42 faces the protrusion 30g of the center tappet 30. Therefore, when the center tappet 30 is pushed by the center cam 24 b having a high lift amount and moves relative to the side tappet member 36, the protrusion 30 g first comes into contact with the spacer member 42. Thereafter, the center tappet 30 pushes the side tappet member 36 through the spacer member 42 and the slide pin member 40. Thereby, the side tappet member 36 is driven by the high lift amount of the center cam 24 b, and this high lift amount is reflected in the lift amount of the valve 16.
In such a case, even if the side tappet 32 is pushed by the side cam 24a having a low lift amount, the side tappet member 36 is moved downward by a lift amount larger than the low lift amount, so the side cam 24a is swung away. As a result, the valve 16 can be lifted with a high lift amount.

In the present embodiment, the amount of valve lift of the side cam 24a is made extremely small.For example, in an engine that injects fuel into the intake port, the valve is stopped slightly while the valve is stopped, It is possible to prevent fuel from unnecessarily collecting on the inner wall surface of the port, and if the side cam 24a is not provided, the tappet unit 8 of the variable valve operating apparatus 1 can be used as a valve suspension mechanism. . That is, in the first position shown in FIG. 11 (a), the side tappet member 36 is not driven by the center cam 24b and the side cam 24a does not exist. , The operation state is driven by the lift amount of the center cam 24b.
As described above, according to the tappet unit 8 of the present invention, it is possible to arbitrarily obtain the valve lift characteristic of either changing the valve lift amount or stopping the valve lift by changing the configuration of the cam 24. It is.

Furthermore, the effect of this embodiment is demonstrated.
In the embodiment of the present invention, the lift amount of the valve 16 can be changed or stopped while the tappet unit 8 is made compact as a whole by the spacer member 42. If the height of the spacer member 42 is adjusted, the lift amount can be adjusted. Further, since the spacer member 42 also determines the orientation (rotation restriction) of the slide pin member 40 in cooperation with the wall portion 60e of the guide member, it is not necessary to provide a separate member for restricting the rotation. 8 can be formed compactly. Furthermore, since the load applied from the center tappet 30 is effectively received by the wall portion 60e through the spacer member 42, the posture retention and load resistance strength of the slide pin member 40 can be satisfied with a simple configuration.

  Furthermore, the configuration in which the spacer member 42 is used for both the change of the valve lift characteristics and the determination of the posture of the slide pin member 40, and the configuration in which the protrusion 30g is formed on the center tappet 30 and the spacer member 42 is brought into contact with the spacer member 42, A tappet unit 8 having a simple configuration can be obtained. As described above, the projection 30g of the center tappet 30, the spacer member 42, and the wall 60e of the guide member 60 make a large lift difference in the lift amount change type and a high lift amount in the valve rest type compact and simple configuration. And the rotation regulation of the slide pin member can be efficiently performed.

  Next, since the space portions 40d and 40e are formed in the slide pin member 40, it is possible to obtain a large lift difference by preventing the protrusion 30g from coming into contact with the slide pin member 40. And the height of the tappet unit 8 can be suppressed low. Further, since the space portion 40d is formed by a concave portion 40b in which the slide pin member 40 is cut out into a concave shape, the space portion 40d also receives the reinforcing rib 30f of the center tappet 30 and interferes with the reinforcing rib 30f and the slide pin member 40. And a larger lift difference can be obtained.

  Next, the side tappets 32 are arranged at intervals in the cam shaft direction C of the camshaft 6, and these are connected by a connecting portion 34, and the center tappet 30 is provided between the two side tappets 32 so as to be relatively movable. Since the cam is composed of two low lift cams 24a for the side tappet 32 and a high lift cam 24b for the center tappet 30, this embodiment can be of a type that changes the lift amount for switching the lift amount. It is suitable as a variable valve device. Further, the connecting portion 34 of the two side tappets 32 is provided in the lower portion of the side tappet 32, and the connecting portion 34 is provided with the slide pin member 40, the spacer member 42, and the guide portion 60. 8 can be formed compactly as a whole.

Next, in the guide hole 60a, a return spring 44 is provided on one end side of the slide pin member 40, and a hydraulic operation chamber 60c is provided on the other end side. It can be switched easily.
Next, a gap is formed between the enlarged portion 42 a of the spacer member 42 and the wall portion 60 e of the opening 60 b of the guide portion 60 so that the spacer member 42 can swing around the axis of the slide pin member 40. Therefore, even if the center tappet 30 is slightly inclined due to the sliding contact load by the center cam 24b, the lower surface of the protrusion 30g and the upper surface of the spacer member 42 can be brought into surface contact. Therefore, uneven wear of the protrusion 30g and the spacer member 42 can be suppressed.

Next, the main configuration of the variable valve operating apparatus for an engine according to the second embodiment of the present invention will be described with reference to FIGS. FIG. 12 is a partial sectional view of a tappet unit and a camshaft for explaining the structure of the tappet unit according to the second embodiment of the present invention, and FIG. 13 shows the campet of the tappet unit according to the second embodiment of the present invention. It is the side view seen from the axial direction.
In the tappet unit 108 according to the second embodiment, the structure of the side tappet member 136 is different from that of the side tappet member 36 of the first embodiment, and other basic structures are the same as those of the first embodiment. Here, only differences from the first embodiment will be described. In addition, the same code | symbol as 1st Embodiment is used with respect to the same structure as 1st Embodiment.

First, as shown in FIGS. 12 and 13, the side tappet member 136 according to the second embodiment is basically composed of two side tappets 132 and a connecting portion 34 connecting them as in the first embodiment. Composed. The structure of the connecting portion 34 is the same as that in the first embodiment.
The side tappet 132 is provided with a roller 170 at an upper portion thereof. These rollers 170 are accommodated in a recess 172 formed in the upper part of the side tappet 132. The roller 170 is rotatably supported by the side tappet 132 via shafts 172 supported by the wall portions on both sides of the concave portion 172. These rollers 170 are in contact with the side cam 24a, and the roller 170 is rotated by the rotation of the side cam 24a, so that the sliding resistance can be reduced.

  Here, the slide pin member 40 and the guide part 60 are formed in the connection part 34 provided in the lower part of the side tappet 132 similarly to 1st Embodiment. Therefore, as in the second embodiment, the roller 170 can be easily provided by effectively utilizing the upper portion of the side tappet 132. As a result, in the second embodiment, as in the first embodiment, a large lift difference in the lift amount change type can be obtained with a compact and simple configuration, and the rotation regulation of the slide pin member is efficiently performed. Furthermore, the sliding load between the side cam 24a and the side tappet 132 can be reduced.

It is a figure which shows the structure of the engine upper part provided with the variable valve apparatus by 1st Embodiment of this invention. It is a perspective view shown in the state where the center tappet and side tappet member of the tappet unit by a 1st embodiment were combined. It is a fragmentary sectional perspective view which expands and shows the tappet unit by 1st Embodiment. It is a perspective view which shows the side tappet member by 1st Embodiment. It is a perspective view which shows a center tappet. It is the bottom view which looked at the center tappet from the lower part. It is sectional drawing of the tappet unit seen along the VII-VII line of FIG. It is sectional drawing of the tappet unit seen along the VIII-VIII line of FIG. It is sectional drawing of the tappet unit seen along the IX-IX line of FIG. It is the elements on larger scale which expand and show the part in which the spacer member was provided in FIG. It is sectional drawing shown similarly to FIG. 8 for demonstrating the effect | action of the variable valve operating apparatus of the engine by 1st Embodiment of this invention. It is a partial cross section figure of a tappet unit and a cam shaft for explaining the structure of a tappet unit by a 2nd embodiment of the present invention. It is the side view which looked at the tappet unit by 2nd Embodiment of this invention from the cam shaft direction.

Explanation of symbols

1 Engine 6 Camshaft 8 Tappet unit 12 Valve stem 24a Side cam (low lift)
24b Center cam (high lift)
30 Center tappet 30e, 30f Reinforcement rib 30g Projection 32 Side tappet 34 Side tappet joint 40 Slide pin member 40b Concave part 40c Flat part 40d Space part 40e in the concave part Hole part (space part)
42 Spacer member 42 Enlarged portion 44 Return spring 60 for slide pin member 40 Guide portion 60a Guide hole 60b Opening portion 60c Hydraulic chamber 60e Wall portion, outer edge portion, posture determining portion

Claims (12)

An engine variable valve operating device capable of switching valve lift characteristics,
A valve cam;
A valve stem;
A tappet unit provided between the valve cam and the valve stem and capable of switching valve lift characteristics;
This tappet unit
A tappet body connected to the valve stem;
A movable tappet provided so as to be relatively movable in the axial direction of the valve stem with respect to the tappet body;
A slide pin member having a substantially circular cross section, which is disposed on the tappet body and is movable between two positions in a direction perpendicular to the axial direction of the valve stem;
A guide hole that is formed in the tappet body and that slidably accommodates the slide pin member, and a guide part having an opening part of the guide hole that opens to the movable tappet side;
A protrusion formed on the movable tappet and projecting toward the opening;
A spacer member fixed to the slide pin member at a position that faces the protrusion when the slide pin member is at one of the two positions and does not face when the slide pin member is at the other position. And
The opening of the guide part opens at least in a range in which the spacer member moves, and the spacer member has an enlarged part protruding from the slide pin member in a radial direction of the slide pin member in a top view, and the guide At least a part of the outer edge portion of the opening of the portion is formed as a posture determining portion that contacts the enlarged portion of the spacer member to guide the movement of the spacer member and suppress the rotation of the slide pin member. A variable valve operating device for an engine.   The slide pin member is formed with a space portion on one side of the spacer member in the axial direction, and the space portion of the movable tappet is located when the slide pin member is at the other position of the two positions. The variable valve operating apparatus for an engine according to claim 1, wherein the protruding part is formed in a size that can receive the protrusion. The tappet body is composed of two side tappets that are spaced apart from each other in the cam shaft direction of the valve cam and a connecting portion that connects these side tappets,
The movable tappet is a center tappet that is provided between the two side tappets and is slidably guided by the side tappets.
The variable valve operating apparatus for an engine according to claim 2, wherein the valve cam has two low lift cams for the two side tappets and a high lift cam for the center tappet.   The variable valve operating apparatus for an engine according to claim 3, wherein the connecting portion is provided at a lower portion of the two side tappets, and the guide portion and the slide pin member are provided at the connecting portion.   The slide pin member is formed with a concave portion in which the slide pin member is notched in a side view, and the space portion of the slide pin member is formed in at least a part of the space formed by the concave portion. 5. The variable valve operating apparatus for an engine according to claim 3 or claim 4. The slide pin member has a hole formed below the concave portion,
The variable valve operating apparatus for an engine according to claim 5, wherein the space portion of the slide pin member is formed in at least one portion of the space formed by the concave portion and the hole portion.   The variable movement of the engine according to claim 5 or 6, wherein the concave portion has a flat bottom surface, and the spacer member is fixed to the flat bottom surface of a part of the concave portion. Valve device.   The variable valve operating apparatus for an engine according to claim 4, wherein the two side tappets are provided with rollers in contact with the two low lift cams in an upper portion thereof.   9. The guide hole formed in the tappet main body is provided with a return spring on one end side of the slide pin member and a hydraulic chamber on the other end side. Variable valve operating system for the engine.   10. A gap is formed between the enlarged portion of the spacer member and the posture determining portion so as to allow the spacer member to swing a predetermined amount around the axis of the slide pin member. The variable valve operating apparatus for an engine according to claim 1. The tappet body is composed of two side tappets that are spaced apart from each other in the cam shaft direction of the valve cam and a connecting portion that connects these side tappets,
The movable tappet is a center tappet that is provided between the two side tappets and is slidably guided by the side tappets.
The variable valve operating apparatus for an engine according to claim 1 or 2, wherein the valve cam is composed of only the cam for the center tappet. An engine variable valve operating device capable of switching valve lift characteristics,
A valve cam;
A valve stem;
A tappet unit provided between the valve cam and the valve stem and capable of switching valve lift characteristics;
This tappet unit
A tappet body that is composed of two side tappets arranged at intervals in the cam shaft direction of the valve cam and a connecting portion that connects these side tappets, and is connected to the valve stem;
A center tappet provided between the two side tappets and guided slidably by the side tappet so as to be relatively movable in the axial direction of the valve stem with respect to the tappet body;
A slide pin member having a substantially circular cross section, which is disposed on the tappet body and is movable between two positions in a direction perpendicular to the axial direction of the valve stem;
A guide hole that is formed in the tappet body and that slidably accommodates the slide pin member, and a guide portion having an opening in which a part of the guide hole is opened to the center tappet side;
A protrusion formed on the center tappet and projecting toward the opening;
A spacer member fixed to the slide pin member at a position that faces the protrusion when the slide pin member is at one of the two positions and does not face when the slide pin member is at the other position. And
The opening of the guide part opens at least in a range in which the spacer member moves, and the spacer member has an enlarged part protruding from the slide pin member in a radial direction of the slide pin member in a top view, and the guide At least a part of the outer edge portion of the opening of the portion is formed as a posture determining portion that abuts on the enlarged portion of the spacer member to guide the movement of the spacer member and suppress the rotation of the slide pin member,
The variable valve operating apparatus for an engine, wherein the valve cam includes two low lift cams for the two side tappets and a high lift cam for the center tappet.

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