JP2013253494A - Valve gear for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent wear of an inner circumferential surface of a changeover pin hole of a rocker arm without need of a receiving member of a special material.SOLUTION: A receiving member 43 formed in a dish-like shape disposed at a bottom part of a changeover pin hole 34b and formed in a rocker arm 34B of the valve gear for an internal combustion engine comprises a plate-like body part 43a contacted with one end portion in the axis L direction of an energizing means 44 stored in the changeover pin hole 34b for energizing a changeover pin 42B, and a flange part 43b prepared by bending an outer circumferential rim of the body part 43a in the axis L direction. In the case the receiving member 43 is moved in the radial direction in the changeover pin hole 34b, since the receiving member 43 is contacted with the inner circumferential surface of the changeover pin hole 34b in a wide area of the flange part 43b, wear of the inner circumferential surface of the changeover pin hole 34b is prevented even if the receiving member 43 is made of a general inexpensive material without need of using a special material.

Description

  The present invention is located on one end side in the axial direction, a plurality of rocker arms arranged side by side in the axial direction, a plurality of switching pins slidably fitted in a plurality of switching pin holes respectively formed in the plurality of rocker arms. An urging means that is accommodated in the switching pin hole and urges the plurality of switching pins toward the other end in the axial direction, and an urging means that is disposed at the bottom of the switching pin hole located at the one end in the axial direction. The present invention relates to a valve operating apparatus for an internal combustion engine including a receiving member that supports one end in the axial direction.

  In a valve operating apparatus for an internal combustion engine that switches valve lift and valve timing by connecting or releasing a plurality of rocker arms to each other with a switching pin, the switching pin is arranged inside the switching pin hole of the rocker arm. Japanese Patent Application Laid-Open No. 2004-151867 discloses a structure in which a spring receiving member that supports an end portion of a return spring that urges the spring in one direction is constituted by a flat washer locked to a roller shaft by a circlip.

Japanese Patent No. 4310016

By the way, what is described in the above-mentioned patent document 1 is that the spring receiving member that supports the end portion of the return spring is constituted by a flat washer, so that the spring receiving member is switched between the rocker arms as the rocker arm swings. When vibrating inside the pin hole, when the spring receiving member is made of an inexpensive stainless steel or the like, there is a possibility that the inner peripheral surface of the switching pin hole with which the edge contacts will be worn. In order to prevent this, it is necessary to configure the spring receiving member with an aluminum material or the like whose surface is anodized, and there is a problem that causes a cost increase.The present invention has been made in view of the above circumstances. An object of the present invention is to prevent wear on the inner peripheral surface of the switching pin hole of the rocker arm without requiring a receiving member of a special material.

  To achieve the above object, according to the first aspect of the present invention, a plurality of rocker arms arranged in parallel in the axial direction and a plurality of switching pin holes respectively formed in the plurality of rocker arms are slidable. A plurality of switching pins that are fitted to each other, an urging means that is housed in the switching pin hole located on one end side in the axial direction and biases the plurality of switching pins toward the other end side in the axial direction, and one end side in the axial direction A receiving member disposed at the bottom of the switching pin hole positioned to support one end in the axial direction of the biasing means, and the plurality of switching pins are moved in the axial direction inside the plurality of switching pin holes. Thus, in the valve operating apparatus for an internal combustion engine that switches the connection state of the plurality of rocker arms, the receiving member includes a plate-like main body portion that abuts one end in the axial direction of the urging means, and an outer peripheral edge of the main body portion. Axial direction A valve gear of an internal combustion engine, characterized by being formed into a dish shape and a bent flange portion is proposed.

  According to the second aspect of the invention, in addition to the configuration of the first aspect, the flange portion is bent from the outer peripheral edge of the main body portion to the other end in the axial direction. A valve gear is proposed.

  According to the invention described in claim 3, in addition to the configuration of claim 2, the rocker arm located on one end side in the axial direction supplies hydraulic oil to one end side in the axial direction of the receiving member. A valve operating apparatus for an internal combustion engine is proposed in which a passage is provided and the receiving member has a through hole through which hydraulic oil can pass.

  The first and second low-speed rocker arms 34A and 34B and the high-speed rocker arm 34C of the embodiment correspond to the rocker arm of the present invention, and the low-speed oil passage 34g of the embodiment corresponds to the hydraulic oil supply passage of the present invention. The spring receiving member 43 of the embodiment corresponds to the receiving member of the present invention, and the return spring 44 of the embodiment corresponds to the biasing means of the present invention.

  According to the configuration of the first aspect, the urging means arranged at the bottom of the switching pin hole formed in the rocker arm of the valve gear of the internal combustion engine is housed in the switching pin hole and urges the switching pin. The plate-shaped main body part with which one axial direction one end part contacts | abuts, and the flange part which bent the outer periphery of the main body part to the axial direction are formed in a dish shape. When the receiving member moves in the radial direction inside the switching pin hole, the receiving member comes into contact with the inner peripheral surface of the switching pin hole over a wide area of the flange portion. Even if it is made of an inexpensive material, wear of the inner peripheral surface of the switching pin hole can be prevented.

  According to the second aspect of the present invention, since the flange portion of the receiving member is bent from the outer peripheral edge of the main body portion toward the other end in the axial direction, the tip of the flange portion comes into contact with the bottom portion of the switching pin hole and wear occurs. Can be prevented.

  According to the third aspect of the present invention, when the receiving member having the flange portion is attached to the existing rocker arm, the hydraulic oil supply passage is blocked by the flange portion of the receiving member, so that the hydraulic oil flows into the switching pin hole. Although there is a possibility of flowing between the bottom and the receiving member, the hydraulic oil trapped between the bottom of the switching pin hole and the receiving member is formed by forming a through hole through which the hydraulic oil can pass in the receiving member. Can be supplied to the switching pin side.

1 is a cross-sectional view of a multi-cylinder internal combustion engine. FIG. 2 is a two-direction arrow view of FIG. 1. FIG. 3 is a view taken along line 3-3 in FIG. 1. FIG. 4 is a sectional view taken along line 4-4 of FIG. FIG. 5 is a sectional view taken along line 5-5 of FIG. FIG. 6 is a sectional view taken along line 6-6 of FIG. FIG. 7 is an enlarged view of part 7 of FIG. 4. The figure which shows the shape of a spring receiving member.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  As shown in FIGS. 1 and 2, the in-line multi-cylinder internal combustion engine E includes a cylinder block 11, a cylinder head 12 coupled to the upper surface of the cylinder block 11, and a head cover 13 coupled to the upper surface of the cylinder head 12. . A piston 15 is slidably fitted in a cylinder bore 14 formed in the cylinder block 11, and a combustion chamber 16 facing the upper surface of the piston 15 is recessed in the lower surface of the cylinder head 12.

  An intake port 12a and an exhaust port 12b are formed in the cylinder head 12, and a pair of intake valve holes 12c and 12c through which the intake port 12a communicates with the combustion chamber 16 are umbrella portions 17a and 17a of the intake valves 17 and 17, respectively. A pair of exhaust valve holes 12d and 12d that are opened and closed and the exhaust port 12b communicates with the combustion chamber 16 are opened and closed by umbrella portions 18a and 18a of the exhaust valves 18 and 18, respectively. Retainers 20 and 20 are provided at the tips of stems 17b and 17b of intake valves 17 and 17 that are slidably supported on the cylinder head 12 via valve guides 19 and 19, respectively. 12 and the retainers 20 and 20 are urged in the valve closing direction by valve springs 21 and 21 arranged between them. Similarly, retainers 23, 23 are provided at the tips of stems 18 b, 18 b of exhaust valves 18, 18 slidably supported on the cylinder head 12 via valve guides 22, 22, and the exhaust valves 18, 18 are provided. Is urged in the valve closing direction by valve springs 24, 24 arranged between the cylinder head 12 and the retainers 23, 23.

  An intake camshaft 27 and an exhaust camshaft 28 are rotatably supported between a holder wall 25 provided on the upper surface of the cylinder head 12 and a camshaft holder 26 fastened to the upper surface. Are provided with first and second low-speed intake cams 29A, 29B and high-speed intake cams 29C for each cylinder, and the exhaust camshaft 28 has first and second low-speed exhaust cams 30A for each cylinder. , 30B and a high-speed exhaust cam 30C.

  An intake side variable valve mechanism 31 that opens and closes the intake valves 17 and 17 is provided between the intake camshaft 27 and the intake valves 17 and 17, and is disposed between the exhaust camshaft 28 and the exhaust valves 18 and 18. Is provided with an exhaust side variable valve mechanism 32 for opening and closing the exhaust valves 18 and 18. Since the intake side variable valve mechanism 31 and the exhaust side variable valve mechanism 32 have substantially the same structure, the intake side variable valve mechanism 31 will be described below as a representative.

  As shown in FIGS. 3 to 6, the intake side variable valve mechanism 31 includes a rocker shaft 33 fixed to the holder wall 25 of the cylinder head 12, and the rocker shaft 33 includes first and second low speed driving mechanisms. One end of the rocker arms 34A and 34B and one end of the high-speed rocker arm 34C sandwiched therebetween are pivotally supported. Tappet screws 35 and 35 are provided at the other ends of the first and second low-speed rocker arms 34A and 34B, which are in contact with the upper ends of the stems 17b and 17b of the intake valves 17 and 17, respectively. The lower end of the lost motion spring 36 is supported by a recess 12e formed on the upper surface of the cylinder head 12, and a lifter 37 provided on the upper end of the lost motion spring 36 contacts a receiving portion 38 provided on the lower surface of the high speed rocker arm 34C. Touch.

  The first and second low-speed rocker arms 34A and 34B have bottomed cylindrical switching pin holes 34a and 34b formed in the direction of the axis L (see FIG. 4) parallel to the crankshaft, and the high-speed rocker arm 34C. The switching pin hole 34c that is open at both ends is formed in the axis L direction. The three switching pin holes 34a to 34c have the same diameter, and are aligned on the axis L when the first and second low speed rocker arms 34A and 34B and the high speed rocker arm 34C are at predetermined positions.

  Cylindrical roller shafts 39A, 39B, and 39C are press-fitted into the three switching pin holes 34a to 34c, respectively, and the rollers 40A, 40B, and 40C are respectively needle bearings on the outer circumferences of the roller shafts 39A, 39B, and 39C. It is supported via 41. The two rollers 40A and 40B are pressed against the first and second low-speed intake cams 29A and 29B by the elastic force of the valve springs 21 and 21, respectively, and the roller 40C is high-speed intake by the elastic force of the lost motion spring 36. It is pressed against the cam 29C.

  Switching pins 42A, 42B, and 42C are slidably fitted in the three roller shafts 39A, 39B, and 39C, respectively. A high speed oil chamber 34d is formed on the bottom side of the switching pin hole 34a of the first low speed rocker arm 34A facing the end of the switching pin 42A, and the high speed oil chamber 34d is connected to the rocker via the high speed oil passage 34e. It communicates with a high speed oil passage 33 a formed inside the shaft 33. A low speed oil chamber 34f is formed on the bottom side of the switching pin hole 34b of the second low speed rocker arm 34B facing the end of the switching pin 42B, and the low speed oil chamber 34f is connected via a low speed oil passage 34g. It communicates with a low speed oil passage 33 b formed inside the rocker shaft 33.

  The switching pin 42B of the second low-speed rocker arm 34B is formed with a recess 42a that opens toward the low-speed oil chamber 34f, and the low-speed oil chamber 34f is fitted with a dish-like spring receiving member 43. The switching pin 42B The return spring 44 is contracted between the recess 42 a and the spring receiving member 43. The first to third switching pins 42A, 42B, and 42C are urged from one end side to the other end side in the axis L direction by the elastic force of the return spring 44, and the switching pin 42A is connected to the high speed oil chamber 34d. When abutting against the bottom wall, the contact surfaces of the switching pins 42A and 42C are located in the gap between the two roller shafts 39A and 39C facing each other, and the contact surfaces of the switching pins 42C and 42B are facing each other. Are located in the gap between the two roller shafts 39C and 39B. In this state, the first and second low-speed rocker arms 34A and 34B and the high-speed rocker arm 34C are separated from each other and can swing independently.

  As shown in FIGS. 4, 7 and 8, the spring receiving member 43 is formed by pressing a stainless steel plate, and the disk-shaped main body 43 a and the outer peripheral edge of the main body 43 a are bent in the direction of the axis L. The flange portion 43b is formed in a dish shape, and four through holes 43c are formed at intervals of 90 ° in the circumferential direction along the boundary between the main body portion 43a and the flange portion 43b. A circular through hole 43d is formed at the center of 43a. The outer peripheral surface of the flange portion 43b is orthogonal to the main body portion 43a and is parallel to the axis L.

  The portion on the bottom wall side of the switching pin hole 34b of the second low-speed rocker arm 34B to which the spring receiving member 43 is attached, that is, the portion that becomes the peripheral wall of the low-speed oil chamber 34f, has a diameter-expanded portion 34h whose inner diameter is slightly increased. (See FIG. 7). The spring receiving member 43 housed in the low speed oil chamber 34f is disposed such that the main body 43a is located on one end side in the axis L direction and the flange 43b is located on the other end side in the axis L direction. At this time, there is a slight clearance α (see FIG. 7) between the outer peripheral surface of the flange portion 43b and the inner peripheral surface of the enlarged diameter portion 34h, and therefore, the spring receiving member 43 housed in the low speed oil chamber 34f It can move slightly in the radial direction within the range of α. Further, in a state where the main body portion 43a is pressed against the bottom wall of the low speed oil chamber 34f by the elastic force of the return spring 44, it is between the end portion of the flange portion 43b of the spring receiving member 43 and the end portion of the switching pin 42B. A slight gap β (see FIG. 7) is formed.

  The low speed oil passage 34g that penetrates the second low speed rocker arm 34B in the radial direction and communicates with the enlarged diameter portion 34h of the low speed oil chamber 34f is formed at the end of the flange portion 43b of the spring receiving member 43 and the end of the switching pin 42B. It opens so that it may straddle the part. At this time, the outlet opening of the low-speed oil passage 34g may be blocked by the roller shaft 39B, but the outlet opening of the low-speed oil passage 34g faces the enlarged diameter portion 34h formed in the switching pin hole 34b. A sufficient amount of hydraulic oil can be supplied to the low speed oil chamber 34f.

  Next, the operation of the embodiment of the present invention having the above configuration will be described.

  During low-speed operation of the internal combustion engine E, low-pressure hydraulic oil is supplied from a hydraulic control device (not shown) to the low-speed oil passage 33b of the rocker shaft 33, and the hydraulic oil flows from the low-speed oil passage 34g of the second low-speed rocker arm 34B. The oil is supplied to the low speed oil chamber 34f. On the other hand, high-pressure hydraulic oil is supplied to the high-speed oil passage 33a of the rocker shaft 33, and the hydraulic oil is supplied from the high-speed oil passage 34e of the first low-speed rocker arm 34A to the high-speed oil chamber 34d. As a result, due to the differential pressure between the low pressure in the low speed oil chamber 34f and the high pressure in the high speed oil chamber 34d, the switching pins 42A to 42C move to the other end side in the axis L direction as shown in FIG.

  When the connection between the first and second low-speed rocker arms 34A and 34B and the high-speed rocker arm 34C by the switching pins 42A to 42C is released in this way, the first low-speed rocker arm 34A is moved to the roller by the first low-speed intake cam 29A. The second low-speed rocker arm 34B is driven via the roller 40B by the second low-speed intake cam 29B, and the intake valves 17 and 17 are driven to open and close with a low lift. At this time, the high-speed rocker arm 34C driven by the high-speed intake cam 29C via the roller 40C is idled separately from the first and second low-speed rocker arms 34A and 34B while expanding and contracting the lost motion spring 36. .

  Conversely, during high speed operation of the internal combustion engine E, high pressure hydraulic oil is supplied to the low speed oil passage 33b of the rocker shaft 33, and the hydraulic oil passes through the low speed oil passage 34g of the second low speed rocker arm 34B. 34f. On the other hand, low-pressure hydraulic oil is supplied to the high-speed oil passage 33a of the rocker shaft 33, and the hydraulic oil is supplied from the high-speed oil passage 34e of the first low-speed rocker arm 34A to the high-speed oil chamber 34d. As a result, the switching pins 42A to 42C move to one end side in the axis L direction due to the differential pressure between the low pressure of the low speed oil chamber 34f and the high pressure of the high speed oil chamber 34d.

  When the first and second low-speed rocker arms 34A and 34B and the high-speed rocker arm 34C are integrally connected by the switching pins 42A to 42C in this way, the high-speed intake cam 29C is configured to have a large swing angle via the roller 40C. The movement of the driven high-speed rocker arm 34C is transmitted to the first and second low-speed rocker arms 34A and 34B, so that the intake valves 17 and 17 are driven to open and close with a high lift. At this time, the first and second low speed intake cams 29A and 29B and the rollers 40A and 40B of the first and second low speed rocker arms 34A and 34B are temporarily separated.

  When the hydraulic control device fails and the supply of hydraulic pressure is interrupted, the switching pins 42A to 42C are forcibly pushed back to the position at the time of low speed operation shown in FIG. Can be prevented from being fixed in a high-power operating state.

  Incidentally, the stainless steel spring receiving member 43 housed in the low speed oil chamber 34f of the second low speed rocker arm 34B vibrates in the radial direction in the low speed oil chamber 34f as the second low speed rocker arm 34B swings. Then, there is a possibility that the spring receiving member 43 repeatedly contacts the inner peripheral surface of the enlarged diameter portion 34h of the switching pin hole 34c of the first low speed rocker arm 34B made of aluminum alloy, and the inner peripheral surface of the enlarged diameter portion 34h may be worn. is there.

  However, according to the present embodiment, since the spring receiving member 43 includes the flange portion 43b connected to the outer peripheral portion of the main body portion 43a, the outer peripheral surface of the relatively large area flange portion 43b is the inner periphery of the enlarged diameter portion 34h. By contacting the surface, it is possible to prevent the inner peripheral surface of the expanded diameter portion 34h made of aluminum alloy from being worn. In particular, since the outer peripheral surface of the flange portion 43b is parallel to the inner peripheral surface of the enlarged diameter portion 34h and contacts in a wide area, wear of the inner peripheral surface of the enlarged diameter portion 34h is further effectively prevented. In the case where a conventional simple disk-shaped spring bearing member having an edge on the outer peripheral portion is employed, it is necessary to prevent wear by making the spring bearing member an anodized aluminum alloy. Accordingly, it is possible to reduce the cost by using an inexpensive stainless steel spring receiving member 43.

  Further, when hydraulic fluid flows from the low speed oil passage 34g of the second low speed rocker arm 34B into the low speed oil chamber 34f, the flange portion 43b of the spring receiving member 43 blocks a part of the outlet opening of the low speed oil passage 34g. Although some hydraulic oil passes through the gap β and flows directly into the low-speed oil chamber 34f, most of the other hydraulic oil passes through the gap α and is on the back side (one end in the axis L direction). Side) and may not flow smoothly into the low speed oil chamber 34f.

  However, according to the present embodiment, the hydraulic oil that has entered the back side of the spring receiving member 43 passes through the four through holes 43c formed at the boundary between the main body portion 43a and the flange portion 43b of the spring receiving member 43. It can pass through and flow into the low speed oil chamber 34f. When the spring receiving member 43 is lifted from the bottom wall of the low speed oil chamber 34f, the hydraulic oil passes through the through hole 43d formed in the center of the main body 43a of the spring receiving member 43 and enters the low speed oil chamber 34f. Can flow in.

  In addition, the outer diameter of the flange portion 43b of the spring receiving member 43 slightly increases as the distance from the main body portion 43a increases (see FIG. 8B), so that it contacts the inner peripheral surface of the enlarged diameter portion 34h of the switching pin hole 34b. Since the tip of the flange portion 43b is bent radially inward to reduce the contact surface pressure, it is possible to more effectively prevent wear on the inner peripheral surface of the enlarged diameter portion 34h.

  Further, if the flange portion 43b of the spring receiving member 43 extends from the main body portion 43a to the one end side in the axis L direction, the tip of the flange portion 43b may come into contact with the corner of the enlarged diameter portion 34h, and may be worn. In the present embodiment, since the flange portion 43b of the spring receiving member 43 extends from the main body portion 43a to the other end side in the axis L direction, it is possible to prevent occurrence of wear due to the tip of the flange portion 43b.

  The embodiments of the present invention have been described above, but various design changes can be made without departing from the scope of the present invention.

  For example, in the embodiment, the flange portion 43b of the spring receiving member 43 extends from the main body portion 43a to the other end side in the axis L direction, but the positional relationship is reversed, and the flange portion 43b extends from the main body portion 43a to the one end in the axis L direction. It may extend to the side.

  The material of the spring receiving member 43 of the present invention is not limited to stainless steel, and the material of the first and second low speed rocker arms 34A and 34B and the high speed rocker arm 34C of the present invention is not limited to an aluminum alloy. Absent.

  In the embodiment, the outer peripheral surface of the flange portion 43b of the spring receiving member 43 is formed in parallel with the inner peripheral surface of the enlarged diameter portion 34h, but the outer diameter of the flange portion 43b slightly increases as the distance from the main body portion 43a increases. You may let them. In this way, the tip of the flange portion 43b that is in contact with the inner peripheral surface of the enlarged diameter portion 34h is bent inward in the radial direction to reduce the contact surface pressure, so that the inner peripheral surface of the enlarged diameter portion 34h is worn. Can be more effectively prevented.

  Further, the valve operating apparatus of the present invention is not limited to the intake side variable valve operating mechanism 31, but may be the exhaust side variable valve operating mechanism 32.

34A First low-speed rocker arm (rocker arm)
34B 2nd low speed rocker arm (rocker arm)
34C Rocker Arm for High Speed (Rocker Arm)
34a Switching pin hole 34b Switching pin hole 34c Switching pin hole 34g Low speed oil passage (hydraulic oil supply passage)
42A switching pin 42B switching pin 42C switching pin 43 spring receiving member (receiving member)
43a body portion 43b flange portion 43c through hole 43d through hole 44 return spring (biasing means)
L axis

Claims (3)

A plurality of rocker arms (34A, 34B, 34C) arranged side by side in the axis (L) direction, and a plurality of switching pin holes (34a, 34b, 34c) respectively formed in the plurality of rocker arms (34A, 34B, 34C) And a plurality of switching pins (42A, 42B, 42C) that are slidably fitted to each other, and the switching pin hole (34b) located on one end side in the axis (L) direction. 42B, 42C) is disposed at the bottom of the switching pin hole (34b) positioned on one end side in the axis (L) direction, and biasing means (44) for biasing the other end side in the axis (L) direction. A receiving member (43) that supports one end of the urging means (44) in the axis (L) direction, and the plurality of switching pins (42A, 42B, 42C) are connected to the plurality of switching pin holes (34a, 34b, Shaft inside 34c) (L) is moved in a direction, said plurality of rocker arms (34A, 34B, 34C) in the valve gear of an internal combustion engine for switching the connection state,
The receiving member (43) has a plate-like main body portion (43a) with which one end portion in the axis (L) direction of the urging means (44) contacts, and an outer peripheral edge of the main body portion (43a). A valve operating apparatus for an internal combustion engine comprising a flange portion (43b) bent in a direction and formed in a dish shape.   2. The valve operating device for an internal combustion engine according to claim 1, wherein the flange portion (43 b) is bent from the outer peripheral edge of the main body portion (43 a) to the other end side in the axis (L) direction.   The rocker arm (34B) positioned on one end side in the axis (L) direction includes a hydraulic oil supply passage (34g) for supplying hydraulic oil to one end side in the axis (L) direction of the receiving member, and the receiving member (43). The valve operating device for an internal combustion engine according to claim 2, characterized in that is provided with through holes (43c, 43d) through which hydraulic oil can pass.

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