JP6899939B1 - Valve gear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an O-ring from coming off from a socket when a hydraulic pressure is applied between a pivot of a valve gear and a socket. A tip portion 6a of a pivot 6 has a front tip portion 6a1 and a rear tip portion 6a2. The socket 7 has a peripheral wall portion 72, a bottom portion 71 capable of contacting the front end portion, and an annular groove 73, and is mounted on the valve bridge 8. The O-ring 10 surrounds the tip portion 6a and is attached to the socket 7 so that the outer edge side is fitted into the annular groove 73. When the pivot 6 is raised most, the gap W1 corresponding to the valve clearance is formed between the front tip portion 6a1 and the bottom portion 71, and the gap W1 is formed between the O-ring 10 and the rear tip portion 6a2. Secured. When the socket 7 over the tip 6a of the pivot 6 is lowered by its own weight in a state where it is not mounted on the valve bridge 8, the O-ring 10 is locked to the rear tip 6a2. [Selection diagram] Fig. 3

Description

The present invention relates to a valve gear.

The internal combustion engine (engine) is provided with a valve gear for driving a valve for intake and exhaust. In this type of valve gear, for example, as shown in Patent Document 1, the rotation of the camshaft causes the rocker arm fixed to the arm shaft to swing, and the pivot (adjustment screw) fixed to the rocker arm moves up and down. Be moved. A concave socket (cap) is attached to the tip of the pivot, and the vertical movement of the pivot causes the valve bridge to move up and down via the socket. Then, a pair of intake valves (or exhaust valves) fixed on both sides of the valve bridge are moved up and down at the same time.

The tip of the pivot is formed in a spherical shape, and the socket is attached to the tip of the pivot so that the spherical tip (spherical portion) is fitted into the socket. An annular groove is formed in the socket, and an annular O-ring (seal ring) made of rubber, resin, or the like is fitted in the annular groove. This O-ring prevents the tip from coming off the socket.

Further, the pivot is fixed in a screw hole formed at one end of the rocker arm in a screwed manner. The rocker arm is formed with a first oil passage that guides engine oil from a lubricating oil pump supplied via an arm shaft to a screw hole. Further, the pivot is formed with a second oil passage in which one end communicates with the first oil passage formed in the rocker arm and the other end communicates with the inside of the socket located on the back side of the annular groove. There is. Then, during the actual operation of the valve gear (internal combustion engine), the engine oil is constantly supplied to the space formed between the tip of the pivot and the socket through the first oil passage and the second oil passage. ..

Japanese Unexamined Patent Publication No. 8-200019

In actual work, when a large pressure (flood control) is applied to the space between the tip of the pivot and the socket, a force is applied to push the O-ring outward, and the O-ring comes off the annular groove and is between the pivot and the socket. Sometimes it got stuck in the gap. When the O-ring fits into the gap in this way, the space between the pivot and the socket is sealed by the O-ring. In such a state, if pressure (flood control) is further applied to the O-ring, the O-ring may be pushed out from the gap and may come off from the socket. If the O-ring comes off, the socket may come off from the tip of the pivot when the internal combustion engine is disassembled during maintenance or the like, and the O-ring may fall into the internal combustion engine or the like. Such a dropped socket may cause a malfunction of an internal combustion engine or the like, which has been a problem.

An object of the present invention is to prevent the O-ring from coming off the socket when a hydraulic pressure is applied between the tip of the pivot and the socket in the valve gear.

The valve gear according to the present invention includes a rocker arm supported in a swingable state, a tip including a front tip and a rear tip, and a main body connected to the tip and fixed to the rocker arm. A pivot that swings ascending and descending, a tubular peripheral wall portion that includes an opening at the upper end, a bottom portion that is arranged at the lower end of the peripheral wall portion, and the peripheral wall portion that orbits the peripheral wall portion. It has an annular groove formed inside, is placed on the valve bridge, covers the tip portion, and surrounds the concave socket and the tip portion that are pushed by the tip portion when the pivot is lowered. A valve gear having such an annular shape and having an O-ring attached to the socket with the outer edge side fitted in the annular groove, the valve bridge and the socket when the pivot is raised to the maximum. In a state where a gap corresponding to the valve clearance between the two is formed between the front tip and the bottom, a gap is secured between the O-ring and the rear tip, and the tip of the pivot is secured. The O-ring is locked to the rear tip portion when the socket covered with the portion is lowered by its own weight in a state where the socket is not mounted on the valve bridge.

In the valve gear, the gap formed between the O-ring and the rear tip portion has the shortest distance among the gaps formed between the front tip portion and the bottom portion. It is preferably larger than the gap.

In the valve gear, the gap formed inside the peripheral wall portion and adjacent to the opening side of the annular groove and the rear end portion thereof is the O-ring. It is preferably larger than the wire diameter of the ring.

In the valve gear, the gap formed between the O-ring and the rear tip portion is preferably 0.3 mm or more.

In the valve gear, the rocker arm has a first oil passage through which oil supplied from an oil pump passes, and one end of the pivot communicates with the downstream side of the first oil passage, and the other end is said. It is preferable to have a second oil passage communicating with the space formed between the socket and the tip portion.

According to the present invention, it is possible to prevent the O-ring from coming off the socket when a hydraulic pressure is applied between the tip of the pivot and the socket in the valve gear.

Cross-sectional view of the valve gear according to the first embodiment Enlarged view of the valve gear pivot and socket area Explanatory drawing showing the positional relationship between the O-ring and the tip of the pivot when the pivot is in the highest position. Explanatory drawing showing the positional relationship between the O-ring and the tip of the pivot in the state where the pivot is most raised in the valve gear according to the second embodiment.

<Embodiment 1>
Embodiment 1 of the present invention will be described with reference to FIGS. 1 to 3. In the present embodiment, the valve gear 1 of the overhead cam type engine (internal combustion engine) will be described.

FIG. 1 is a cross-sectional view of the valve gear 1 according to the first embodiment. In FIG. 1, reference numeral 2 indicates a rocker arm, and the rocker arm 2 is supported by an arm shaft 3 in a swingable state.

The rocker arm 2 has a long shape extending in the left-right direction in FIG. 1, and a roller 4 is rotatably supported by one end (right end in FIG. 1) 2a. The camshaft 5 is in contact with the roller 4. A pivot 6 is fixed to the other end (left end in FIG. 1) 2b of the rocker arm 2. The pivot 6 has a shape in which the front end side faces downward and the rear end side is fixed to the rocker arm 2. Such a pivot 6 swings ascending and descending in conjunction with the swinging rocker arm 2. The rocker arm 2 of the present embodiment is a so-called elephant foot type, and a socket (cap) 7 is put on a tip portion 6a (see FIG. 2) of a pivot 6 facing downward. The socket 7 is placed on the upper surface of the valve bridge 8 in a state of being opened upward. A predetermined valve clearance C is provided between the socket 7 and the upper surface of the valve bridge 8 as described later.

A hole 81 is formed in the center of the valve bridge 8, and a guide pin 83 fixed to the cylinder 82 is inserted into the hole 81. The upper ends of a pair of intake valves (or exhaust valves) 84 and 85 are fixed to the left and right sides of the valve bridge 8 in FIG. 1, respectively. Two return springs 86, 87 through which the upper portions of the valves 84 and 85 are inserted are arranged between both sides of the valve bridge 8 and the cylinder 82, and pressing members 88 are arranged at the upper ends of the return springs 86 and 87, respectively. , 89 are arranged.

FIG. 2 is an enlarged view of the vicinity of the pivot 6 and the socket 7 of the valve gear 1. For convenience of explanation, the cross-sectional structure of the socket 7 is shown in FIG. As shown in FIG. 2, a screw hole 21a including a female screw surface is formed at the end 2a of the rocker arm 2 so as to penetrate substantially in the vertical direction. The pivot 6 has an elongated shape (rod shape) extending in the vertical direction as a whole, and its tip portion 6a is formed in a substantially spherical shape as a whole. The main body 6b of the pivot 6 connected to the rear end side of the tip 6a has a longitudinal shape (rod shape) as a whole, and has a male screw surface on the outer peripheral surface thereof. The outer diameter of the main body 6b of the pivot 6 is smaller than the maximum diameter of the tip 6a.

The pivot 6 is inserted into the screw hole 21a from the rear end (rear end of the main body 6b) 6c side so that the tip 6a faces downward, and the male screw surface of the main body 6b is inserted into the female screw surface of the screw hole 21a. It is attached to a predetermined position of the end portion 2a of the rocker arm 2 in a form of being screwed into. The rear end 6c of the pivot 6 protrudes upward from the end 2a of the rocker arm 2, and the nut 9 is screwed onto the protruding rear end (rear end of the main body 6b) 6c of the pivot 6. The pivot 6 is fixed to the end 2a of the rocker arm 2.

The tip portion 6a of the pivot 6 is housed inside the concave socket 7. The socket 7 is made of a metal-based material made of metal or alloy processed into a predetermined shape, and has a container-like shape (concave shape) that opens upward as a whole. The socket 7 includes a tubular (cylindrical) peripheral wall portion 72 including an opening 72a at one end (upper end), and a bottom portion 71 arranged at the other end (lower end) of the peripheral wall portion 72. Further, on the inside (inner peripheral surface) of the peripheral wall portion 72, an annular groove 73 formed so as to orbit is provided.

The upper surface of the bottom 71 of the socket 7 has a spherical (hemispherical) concave shape. Therefore, the upper surface of the bottom portion 71 is referred to as a "concave spherical surface 71a". Further, in the center of the bottom portion 71, a through hole 71b extending in the thickness direction is provided so as to communicate the inside and the outside of the socket 7. The socket 7 is placed so as to cover the tip portion 6a of the pivot 6 and the lower surface of the bottom portion 71 is in contact with the upper surface of the valve bridge 8.

The tip portion 6a of the pivot 6 is connected to the front tip portion 6a1 arranged on the front side (lower side) and the rear side (upper side) of the front tip portion 6a1 and is connected to the main body portion 6b. It is composed of a part 6a2. The front end portion 6a1 has a substantially hemispherical shape, and includes a convex spherical surface (hereinafter, referred to as “convex spherical surface 60a1”) whose outer diameter gradually decreases toward the front side. Further, the rear tip portion 6a2 has a shape as if the hemisphere was cut by a surface arranged parallel to the virtual bottom surface thereof. The rear tip portion 6a2 includes a spherical surface 60a2 (hereinafter, referred to as "rear surface 60a2") which is connected to the convex spherical surface 60a1 and whose outer diameter gradually decreases toward the rear side.

The concave spherical surface 71a is located at a position higher than the center OP of the virtual sphere corresponding to the convex spherical surface 60a1 in the state of being in contact with the convex spherical surface 60a1, and is in the horizontal direction from the vertical line V passing through the central OP. It corresponds to the concave spherical surface of a virtual heterogeneous sphere whose central OS1 is a circular locus separated by a distance R. Therefore, the concave spherical surface 71a and the convex spherical surface 60a1 come into contact with each other on the extension line of the straight line passing through the center OS1 and the center OP. The central OP is on the boundary surface X between the front end portion 6a1 and the rear tip portion 6a2. In the present specification, the boundary surface X is included on the front end portion 6a1 side (convex spherical surface 60a side).

An annular groove 73 is formed inside the peripheral wall portion 72 of the socket 7 (on the inner peripheral surface side). The annular groove 73 is provided in the peripheral wall portion 72 so as to surround the rear surface 60a2 of the tip portion 6a when the positional relationship between the pivot 6 and the socket 7 is in a reference state described later. An O-ring 10 is attached to such an annular groove 73. The O-ring 10 is made of an elastic material such as rubber or resin formed in an annular shape, and the outer edge side thereof is fitted in contact with the annular groove 73. Note that FIG. 2 shows a cross section of the O-ring 10 in a state of being fitted in the annular groove 73.

As shown in FIG. 2, a predetermined valve clearance C is set between the valve bridge 8 and the socket 7. The valve clearance C is a case where the convex spherical surface 60a1 of the tip portion 6a of the pivot portion 6 is brought into contact with the concave spherical surface 71a of the bottom portion 71 of the socket 7 (that is, the concave spherical surface 71a of the socket 7 is in contact with the concave spherical surface 71a of the socket 7 in the state where the pivot 6 is most raised. It is a gap formed between the socket 7 and the valve bridge 8 when the socket 7 is lifted so as to come into contact with the convex spherical surface 60a1 of the pivot 6.

FIG. 3 is an explanatory diagram showing a positional relationship between the O-ring 10 and the tip portion 6a of the pivot 6 in a state where the pivot 6 is most raised. As shown in FIG. 3, the socket 7 is mounted on the valve bridge 8, and the peripheral wall portion 72 surrounds the tip portion 6a of the pivot 6. The height position of the opening 72a of the peripheral wall portion 72 is set to be higher than the height position of the rear tip portion 6a2. The convex spherical surface 60a1 at the tip 6a of the pivot 6 and the concave spherical surface 71a at the bottom 71 of the socket 7 are separated from each other, and a gap corresponding to the valve clearance C is formed between them.

In addition, in this specification, the state of the pivot 6 and the socket 7 of the positional relationship shown in FIG. 3 may be referred to as a "reference state".

The maximum diameter of the tip portion 6a of the pivot 6 (the outer diameter at the boundary between the front tip portion 6a1 and the rear tip portion 6a2) is set to be larger than the inner diameter of the O-ring 10. Therefore, when the socket 7 is attached, the tip portion 6a of the pivot 6 passes through the O-ring 10 while being elastically deformed so as to expand the O-ring 10. The O-ring 10 can be locked to the rear tip portion 6a2 when the socket 7 covered with the tip portion 6a of the pivot 6 is lowered by its own weight in a state where it is not mounted on the valve bridge 8. .. Such an O-ring 10 prevents the socket 7 from coming off the tip 6a of the pivot 6.

The O-ring 10 has a perfect circular shape as a whole when viewed in a plan view. Further, as shown in FIG. 3, the O-ring 10 has a circular cross section (perfect circular shape). A substantially half portion (a portion having a substantially semicircular cross section) of the O-ring 10 from the outer edge side to the inner edge side is fitted in the annular groove 73. That is, the inner edge side of the O-ring 10 protrudes from the annular groove 73 and is exposed, and the O-ring 10 is in a state of being raised from the peripheral wall portion 72.

The annular groove 73 is formed in an annular shape on the inside (inner peripheral surface) of the cylindrical peripheral wall portion 72 near the opening 72a so as to orbit. As shown in FIG. 3, the cross section of the annular groove 73 has a substantially semicircular concave shape. Such an annular groove 73 is arranged between the bottom side edge portion 74 and the opening side edge portion 75. The bottom side edge portion 74 is an annular raised portion formed inside the peripheral wall portion 72 and adjacent to the bottom portion 71 side of the annular groove 73. The opening side edge portion 75 is an annular raised portion formed inside the peripheral wall portion 72 and adjacent to the opening 72a side of the annular groove 73. The bottom side edge portion 74 and the opening side edge portion 75 are formed inside the peripheral wall portion 72 so as to orbit while arranging in parallel with each other. The bottom side edge portion 74 and the opening side edge portion 75 each have a shape in which they are connected in an annular shape while protruding from the inner peripheral surface (inner peripheral surface near the center in the vertical direction) of the peripheral wall portion 72. In the case of the present embodiment, the opening side edge portion 75 is arranged on the inner peripheral edge side of the opening portion 72a.

As shown in FIG. 3, a gap W1 is formed between the O-ring 10 and the rear tip portion 6a2 of the pivot 6. In the present specification, the gap W1 formed between the O-ring 10 and the rear tip portion 6a2 of the pivot 6 may be referred to as a "first gap W1". The first gap W1 is set so that the space S1 between the socket 7 and the tip portion 6a of the pivot 6 is not sealed when the valve gear 1 is in operation. The first gap W1 is a gap formed at the shortest distance between the O-ring 10 and the rear tip portion 6a2. More specifically, the first gap W1 is the shortest distance between the rear surface 60a2 of the rear tip 6a2 at the tip 6a and the inner edge side surface of the O-ring 10 exposed from the annular groove 73. It is a gap formed. The pivot 6 and the socket 7 are arranged coaxially (the axis passing through the center of the pivot 6 and the axis passing through the center of the socket 7 are on the same straight line), and the first gap W1 surrounds the pivot 6. It is formed in a ring shape.

The first gap W1 is set to, for example, 0.3 mm or more in the above reference state. The upper limit of the first gap W1 is not particularly limited as long as the object of the present invention is not impaired. The first gap W1 is usually smaller than the wire diameter (outer diameter) of the O-ring 10.

Further, as shown in FIG. 3, in the above reference state, there is a gap W2 corresponding to the valve clearance C between the concave spherical surface 71a of the bottom portion 71 of the socket 7 and the convex spherical surface 60a1 of the tip portion 6a of the pivot 6. It is formed. In the present specification, the gap W2 corresponding to the valve clearance C may be referred to as a "second gap W2". Further, among the second gaps W2, the gap having the shortest distance in the above reference state may be particularly referred to as the "shortest second gap W22".

In the case of the present embodiment, the shortest second gap W22 is formed between the concave spherical surface 71a and the convex spherical surface 60a1 on the extension line of the straight line passing through the center OS1 and the center OP described above. Such a shortest second gap W22 is formed in an annular shape so as to surround the tip end portion 6a1 of the pivot 6.

In the present embodiment, in the above reference state, the first gap W1 is set to be larger than the shortest second gap W22.

The space S1 formed between the tip portion 6a of the pivot 6 and the socket 7 is arranged above the first space S11 arranged below the shortest second gap W22 and above the shortest second gap W22. It is composed of a second space S12 to be created.

Further, the gap formed between the opening side edge portion 75 of the socket 7 and the rear tip portion 6a2 of the pivot 6 is preferably larger than the wire diameter of the O-ring 10 in the above reference state. In the present specification, the gap formed between the opening side edge portion 75 of the socket 7 and the rear tip portion 6a2 of the pivot 6 may be referred to as a "third gap W3". The third gap W3 is between the opening side edge portion 75 and the rear surface 60a2 of the rear tip portion 6a2 (however, the rear surface 60a2 above the portion where the first gap W1 is formed). It is a gap formed at the shortest distance. When the third gap W3 is larger than the wire diameter of the O-ring 10 in this way, the O-ring 10 pivots when hydraulic pressure is applied to the space S1 between the tip portion 6a of the pivot 6 and the socket 7. It is prevented from being fitted between the tip portion 6a (rear side tip portion 6a2) of 6 and the socket 7 (opening side edge portion 75) and sealing between them.

As shown in FIG. 2 and the like, a first oil passage 21b is formed inside the rocker arm 2. A second oil passage 63 is formed inside the pivot 6 so that one end communicates with the first oil passage 21b formed in the rocker arm 2 and the other end communicates with the space in the socket 7. Engine oil (hereinafter, may be simply referred to as “oil”) supplied from a lubricating oil pump (not shown) via an arm shaft 3 is screwed with a pivot 6 through a first oil passage 21b. It is supplied to the screw hole 21a. Then, a part of the oil supplied to the screw hole 21a is discharged from the opening end 63a of the second oil passage 63 at the tip end portion 6a of the pivot 6 through the second oil passage 63 and into the socket 7. Be supplied. The oil supplied into the socket 7 is mainly discharged to the outside of the socket 7 through the through hole 71b provided in the bottom portion 71. The oil discharged from the through hole 71b is supplied to the upper surface of the valve bridge 8.

In the valve gear 1 of the present embodiment, the rotation of the camshaft 5 causes the rocker arm 2 fixed to the arm shaft 3 to swing, and the pivot 6 fixed to the rocker arm 2 to swing up and down. To. Then, due to the swing of the pivot 6, the valve bridge 8 is moved up and down via the socket 7, and a pair of intake valves (or exhaust valves) 84 and 85 fixed on both sides of the valve bridge 8 are moved up and down at the same time. Be moved.

Further, during the actual operation of the valve gear 1, engine oil from the lubricating oil pump supplied via the arm shaft 3 passes through the first oil passage 21b and the second oil passage 63, and the tip portion 6a of the pivot 6 is passed. It is always supplied to the space S1 (see FIG. 3) between the socket 7 and the socket 7.

In the valve gear 1 of the present embodiment, the first gap W1 is secured so that the O-ring 10 does not come into contact with the rear tip portion 6a2 (rear surface 60a2) of the pivot 6 in the above reference state (FIG. 3). Therefore, in the above reference state, even if the pressure (flood control) in the space S1 becomes high, the oil can escape to the outside of the socket 7 through the first gap W1.

Further, in the valve gear 1 of the present embodiment, the first gap W1 is set to be larger than the shortest second gap W22. The engine oil supplied under pressure from the opening end 63a of the pivot 6 is first supplied into the second gap W2 formed between the convex spherical surface 60a and the concave spherical surface 71a. The engine oil is supplied from the first space S11 in the second gap W2 to the second space S12 through the shortest second gap W22. The second space S12 is mainly between the peripheral wall portion 72 of the socket 7 and the rear tip portion 6a2 (rear surface 60a2) of the pivot 6, and between a part of the concave spherical surface 71a and the front tip portion 6a1. , And the O-ring 10 exposed from the annular groove 73 and the rear tip portion 6a2 (rear surface 60a2). The size (width) of such a second space S12 is larger than the distance (width) between the convex spherical surface 60a and the concave spherical surface 71a forming the first space S11. The convex spherical surface 60a and the concave spherical surface 71a forming the first space S11 function like so-called orifices, and the pressure of the engine oil moving from the first space S11 to the second space S12 (the engine passing through the first gap W1). Oil pressure) can be lowered. As a result, when the engine oil moves in the second space S12, the O-ring 10 attached to the annular groove 73 is suppressed from being pushed up by the engine oil.

A large amount of oil is normally applied to the first space S11 when the socket 7 is in contact with the valve bridge 8 and the through hole 71b at the bottom 71 of the socket 7 is blocked by the valve bridge 8. .. At that time, the tip portion 6a (convex spherical surface 60a1) of the pivot 6 is in a state of being separated from the bottom portion 71 (concave spherical surface 71a1) of the socket 7 (the above-mentioned reference state) corresponding to the valve clearance C. Therefore, in the present embodiment, the first gap W1 is secured so that the O-ring 10 does not come into contact with the rear tip portion 6a2 (rear surface 60a2) of the pivot 6 and the space S1 is not sealed. Further, in order to prevent the O-ring 10 from being pushed up by the flood control, the first gap W1 in the reference state is made larger than the shortest second gap W22.

Further, since the third gap W3 of the present embodiment is larger than the wire diameter of the O-ring 10, the engine oil can smoothly pass through the third gap W3, and the O-ring 10 becomes the pivot 6. It is suppressed from being fitted between the socket 7 and the socket 7.

When the valve gear 1 of the present embodiment is disassembled at the time of maintenance or the like, the socket 7 covered with the tip portion 6a of the pivot 6 is not mounted on the valve bridge 8 and is lowered by its own weight. Even in this case, the O-ring 10 can be locked to the rear tip portion 6a2. Therefore, the socket 7 is prevented from coming off from the tip portion 6a of the pivot 6.

Unlike the present embodiment, when the size (width) of the first gap W1 is equal to or less than the size (width) of the shortest second gap W22, the convex spherical surface 60a and the concave surface forming the first space S11 are formed. The spherical surface 71a does not function as an orifice. Therefore, when the engine oil that moves under pressure in the space S1 passes through the first gap W1, it vigorously contacts the O-ring 10 and the O-ring 10 easily falls off from the annular groove 73. ..

In the present embodiment, the cross-sectional shape of the O-ring 10 is circular (regular), but the present invention is not limited to this, and in other embodiments, for example, an elliptical shape, a regular hexagonal shape, or the like. It may have a polygonal shape or the like. At that time, the wire diameter of the O-ring compared with the third gap W3 is the outer diameter having the largest cross-sectional shape. For example, if the cross-sectional shape is an elliptical O-ring, the wire diameter is the length of the major axis of the ellipse, and if the cross-sectional shape is a regular hexagonal O-ring, the wire diameter is the longest diagonal of the regular hexagon. Become.

<Embodiment 2>
Next, the valve gear 1A according to the second embodiment will be described with reference to FIG. The valve gear 1A of the present embodiment is obtained by changing the socket 7 of the first embodiment to another socket 7A. FIG. 4 is an explanatory diagram showing the positional relationship between the O-ring 10 and the tip portion 6a of the pivot 6 in the state where the pivot 6 is most raised in the valve gear 1A according to the second embodiment. FIG. 4 shows the pivot 6 and the socket 7A in the reference state as in the first embodiment. That is, the convex spherical surface 60a1 of the pivot 6 and the concave spherical surface 71Aa at the bottom 71A of the socket 7A are separated from each other, and a gap corresponding to the valve clearance is formed between them.

Similar to the first embodiment, the socket 7A has a container shape (concave shape) that opens upward as a whole, and has a cylindrical (cylindrical) peripheral wall portion 72A including an opening 72Aa at the upper end and a peripheral wall portion. It is provided with a bottom portion 71A arranged at the lower end of the 72A. Further, on the inside (inner peripheral surface) of the peripheral wall portion 72A, an annular groove 73A formed so as to orbit is provided as in the first embodiment. The annular groove 73A is provided in the peripheral wall portion 72A so as to surround the rear surface 60a2 of the tip portion 6a in the reference state. The annular groove 73A is arranged between the bottom side edge portion 74A and the opening side edge portion 75A. The bottom side edge portion 74A of the present embodiment is set to have a longer length in the vertical direction than that of the first embodiment. The lower end of the bottom edge portion 74A is arranged above the boundary surface X between the front tip portion 6a1 (convex spherical surface 60a1) and the rear tip portion 6a2 (rear surface 60a2). The upper surface of the bottom portion 71A of the socket 7A is provided with a concave spherical surface 71Aa having a shape similar to the convex spherical surface 60a1 of the pivot 6, unlike the first embodiment. Similar to the first embodiment, a through hole 71Ab is provided in the center of the bottom portion 71A. The socket 7A is placed on the upper surface of the valve bridge 8 in a state of being covered with the tip portion 6a of the pivot 6.

As shown in FIG. 4, an annular concave groove portion 76A is formed in a portion of the inner portion of the socket 7A that surrounds the vicinity of the boundary surface X of the tip portion 6a. The concave groove portion 76A faces the surface of the tip portion 6a near the boundary surface X so as to straddle the boundary surface X while maintaining a distance. The recessed groove portion 76A is provided to prevent the tip portion 6a from interfering with the inner portion of the socket 7A when the pivot 6 swings in the socket 7A so as to rise and fall. The surface of the concave groove portion 76A does not form a concave spherical surface 71Aa.

In such a valve gear 1A of the present embodiment, as shown in FIG. 4, there is a gap (similar to that of the first embodiment) between the O-ring 10 and the rear tip portion 6a2 of the pivot 6 in the reference state. 1st gap) WA1 is secured. The pivot 6 and the socket 7A are arranged coaxially as in the first embodiment. Then, as shown in FIG. 4, in the reference state, a gap (second gap) WA2 corresponding to the valve clearance is formed between the concave spherical surface 71Aa of the socket 7A and the convex spherical surface 60a1 of the pivot 6. Of the second gap WA2, the gap having the shortest distance in the above reference state may be particularly referred to as "shortest second gap WA22". The shortest second gap WA22 of the present embodiment is formed at the shortest distance between the upper end of the concave spherical surface 71Aa and the convex spherical surface 60a1 of the front end portion 6a1. The upper end of the concave spherical surface 71Aa is arranged below (front side) the boundary surface X between the front end portion 6a1 and the rear tip portion 6a2.

The space SA1 formed between the tip portion 6a of the pivot 6 and the socket 7A is arranged above the first space SA11 arranged below the shortest second gap WA22 and above the shortest second gap WA22. It consists of a second space SA12.

In the valve gear 1A of the present embodiment, the first gap AW1 is secured so that the O-ring 10 does not come into contact with the rear tip portion 6a2 (rear surface 60a2) of the pivot 6 in the above reference state (FIG. 4). Therefore, in the above reference state, even if the pressure (flood control) in the space SA1 becomes high, the oil can escape to the outside of the socket 7A through the first gap WA1.

Further, in the valve gear 1A of the present embodiment, as in the first embodiment, the first gap WA1 is set to be larger than the shortest second gap WA22. The engine oil supplied under pressure from the opening end 63Aa of the pivot 6 is first supplied into the second gap WA2 formed between the convex spherical surface 60a and the concave spherical surface 71a. The engine oil is supplied from the first space SA11 in the second gap WA2 to the second space SA12 through the shortest second gap WA22. The second space SA12 mainly has a recessed groove portion 76A and a tip portion 6a (front tip portion 6a1 and rear side) between the peripheral wall portion 72A of the socket 7A and the rear tip portion 6a2 (rear surface 60a2) of the pivot 6. It is formed between the tip portion 6a2), the O-ring 10 exposed from the annular groove 73A, and the rear tip portion 6a2 (rear surface 60a2). The size (width) of such a second space SA12 is larger than the distance (width) between the convex spherical surface 60a and the concave spherical surface 71a forming the first space SA11. The convex spherical surface 60a and the concave spherical surface 71Aa forming the first space SA11 function like so-called orifices, and the pressure of the engine oil moving from the first space SA11 to the second space SA12 (the engine passing through the first gap WA1). Oil pressure) can be lowered. As a result, when the engine oil moves in the second space SA12, the O-ring 10 attached to the annular groove 73A is suppressed from being pushed up by the engine oil.

Further, in the valve gear 1A of the present embodiment, as in the first embodiment, when the valve gear 1A is disassembled at the time of maintenance or the like, the socket 7A covered with the tip portion 6a of the pivot 6 is not mounted on the valve bridge 8. The O-ring 10 can be locked to the rear tip portion 6a2 even when the O-ring 10 is in a state of being lowered by its own weight. Therefore, the socket 7A is prevented from coming off from the tip portion 6a of the pivot 6.

1 ... valve gear, 2 ... rocker arm, 21b ... first oil passage, 3 ... arm shaft, 4 ... roller, 5 ... camshaft, 6 ... pivot, 6a ... tip, 6a1 ... front tip, 6a2 ... rear Side tip, 6b ... Main body, 6c ... Rear end, 63 ... Second oil passage, 7 ... Socket, 71 ... Bottom, 71a ... Concave spherical surface, 71b ... Through hole, 72 ... Peripheral wall, 72a ... Opening, 73 ... annular groove, 74 ... bottom side edge, 75 ... opening side edge, 8 ... valve bridge, 9 ... nut, 10 ... O-ring, C ... valve clearance, W1 ... first gap, W2 ... second gap, W22 ... Shortest second gap, W3 ... Third gap, S1 ... Space, S11 ... First gap, S12 ... Second gap, X ... Boundary surface between front tip and rear tip

Claims (4)

A rocker arm that is supported in a swingable state,
A tip portion including a front tip portion having a discharge port for discharging oil, a rear tip portion connected to the rear side of the front tip portion, and a main body connected to the tip portion and fixed to the rocker arm. A pivot that has a part and swings up and down,
It has a tubular peripheral wall portion including an opening at the upper end, a bottom portion arranged at the lower end of the peripheral wall portion, and an annular groove formed inside the peripheral wall portion so as to circulate, and is mounted on a valve bridge. A concave socket that is placed on the tip of the valve and pushed by the tip when the pivot is lowered.
It is provided with an O-ring that forms an annular shape that surrounds the tip portion and is attached to the socket so that the outer edge side is fitted into the annular groove.
A valve gear that locks the O-ring to the rear tip when the socket covered on the tip of the pivot is lowered by its own weight in a state where it is not mounted on the valve bridge. ,
The bottom portion has a through hole portion that communicates the inside and the outside of the socket.
It is the state when the pivot is raised most, and is in a shape that surrounds the tip portion between the inner surface of the socket mounted on the valve bridge and the outer surface of the tip portion of the pivot portion. In a reference state in which a space capable of accommodating oil discharged from the discharge port is formed and the through hole is closed by the valve bridge.
The O-ring and the rear tip portion form an annular shape that surrounds the pivot, communicate with the discharge port through the space, and communicate with the opening of the peripheral wall portion. 1 gap is secured ,
In the reference state, it is composed of a part of the space, has a size corresponding to the valve clearance between the valve bridge and the socket, and allows oil discharged from the discharge port to pass to the first gap side. A second gap is secured between the tip of the tip and the inner surface of the socket.
The first gap is larger than the shortest second gap, which is the shortest gap among the second gaps.
The space has a first space arranged below the shortest second gap and a second space arranged above the shortest second gap.
The width between the inner surface of the socket forming the second space and the outer surface of the tip portion is greater than the width between the inner surface of the socket forming the first space and the outer surface of the tip portion. Also a large valve gear. The gap formed inside the peripheral wall portion and adjacent to the opening side of the annular groove between the annular opening side edge portion and the rear end portion is larger than the wire diameter of the O-ring. The valve gear according to claim 1. The valve gear according to claim 1 or 2, wherein the first gap formed between the O-ring and the rear tip portion is 0.3 mm or more. The rocker arm has a first oil passage through which oil supplied from an oil pump passes.
The pivot has a second oil passage in which one end communicates with the downstream side of the first oil passage and the other end comprises the discharge port and communicates with the space formed between the socket and the tip portion. The valve operating device according to any one of claims 1 to 3.

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