Variable valve device

Abstract

The invention provides a variable valve device which appropriately supplies lubricating oil to components of a switching mechanism and a rocker arm to improve the lubricity of each component. A variable valve device (40) is provided with: a pair of cam housings (42a, 42b) separated in a predetermined direction; a pair of rocker shafts (47, 48) supported by the pair of cam housings; a plurality of rocker arms (35a, 35b, 37) that are supported so as to be able to swing by the pair of rocker arm shafts; a switching mechanism (50) that connects and disconnects the air intake arms; and an upper housing (49) on the pair of cam housings. A first injection hole for supplying lubricating oil to the switching mechanism and a second injection hole for supplying lubricating oil to the plurality of rocker arms are formed in the upper housing. The passage length from the lubrication groove around the camshaft (41) to the second injection hole is longer than the passage length from the lubrication groove to the first injection hole.

Description

Technical Field

[0001] The present invention relates to a variable valve device. Background Art

[0002] Conventionally, as a variable valve device, a device that connects multiple rocker arms to switch valve operation is known (for example, refer to Patent Document 1). In the variable valve device described in Patent Document 1, a pair of rocker arms are arranged adjacent to each other, and a connecting pin is provided in the pin hole of one rocker arm. The pair of rocker arms are connected by pressing a part of the connecting pin into the pin hole of the other rocker arm, and the pair of rocker arms are separated by pulling out a part of the connecting pin from the pin hole of the other rocker arm. By switching the connection and separation of the pair of rocker arms, the cam for valve lift is switched.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Patent No. 5907552 Gazette

[0006] Technical Problem to be Solved by the Invention

[0007] The above-described variable valve device also requires lubrication, but the number of components to be lubricated increases, and the lubrication passage becomes complex. Due to the increase in the number of components to be lubricated and the complication of the lubrication passage, it is difficult to appropriately supply lubricating oil to each component, which may lead to a reduction in durability. Summary of the Invention

[0008] The present invention has been made in view of the above problems, and an object thereof is to provide a variable valve device that can appropriately supply lubricating oil to each component to improve the lubricity of each component.

[0009] Technical Means for Solving the Technical Problem

[0010] One aspect of the variable valve device of the present invention solves the above problems by the following solution, that is, a variable valve device capable of changing the valve operation in a cylinder head, comprising: a pair of cam housings separated in a specified direction within the cylinder head; a camshaft supported by the cylinder head and the pair of cam housings; a pair of rocker shafts supported at opposite positions of the pair of cam housings; a plurality of rockers swingably supported by the pair of rocker shafts; a switching mechanism that connects and disconnects the intake arms of the plurality of rockers; and an upper housing supported at both ends on the upper surfaces of the pair of cam housings, with a first injection hole for supplying lubricating oil to the switching mechanism and a second injection hole for supplying lubricating oil to the plurality of rockers formed in the upper housing, and lubricating oil is pressed from a lubricating groove around the camshaft toward the first injection hole and the second injection hole, and the passage length from the lubricating groove to the second injection hole is longer than the passage length from the lubricating groove to the first injection hole.

[0011] Effects of the Invention

[0012] In the variable valve device according to one aspect of the present invention, the passage length from the lubricating groove around the camshaft to the second injection hole is longer than the passage length from the lubricating groove to the first injection hole. Therefore, the hydraulic pressure of the lubricating passage connected to the first injection hole on the switching mechanism side increases. Even if the number of components to be lubricated increases due to the switching mechanism, an appropriate amount of lubricating oil is supplied from the first injection hole to the switching mechanism and an appropriate amount of lubricating oil is supplied from the second injection hole to the plurality of rockers. Therefore, each component of the switching mechanism and the plurality of rockers is properly lubricated. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a right side view of the engine and the body frame of this embodiment.

[0014] Figure 2 It is a right side view of the upper part of the engine with the cylinder head cover of this embodiment removed.

[0015] Figure 3 It is a perspective view of the upper part of the engine with the cylinder head cover of this embodiment removed.

[0016] Figure 4 It is a top view schematic of the variable valve device of this embodiment.

[0017] Figure 5 It is a schematic diagram of the variable valve device of this embodiment.

[0018] Figure 6 It is a top view and a bottom view of the upper housing of this embodiment.

[0019] Figure 7 is a top view inside the cylinder head of this embodiment.

[0020] Figure 8 is Figure 7 a cross-sectional view of the cylinder head taken along line A-A.

[0021] Figure 9 is Figure 8 a cross-sectional view of the cylinder head taken along line B-B.

[0022] Figure 10 is Figure 7 a cross-sectional view of the cylinder head taken along line C-C.

[0023] Figure 11 is Figure 7 a cross-sectional view of the cylinder head taken along line D-D.

[0024] Figure 12 is Figure 7 a cross-sectional view of the cylinder head taken along line E-E.

[0025] Figure 13 is Figure 8 a cross-sectional view of the cylinder head taken along line F-F.

[0026] Figure 14 is Figure 13 a cross-sectional view of the cylinder head taken along line G-G.

[0027] Figure 15 is Figure 7 a cross-sectional view of the cylinder head taken along line H-H.

[0028] Figure 16 is Figure 7 a cross-sectional view of the cylinder head taken along line I-I.

[0029] Symbol Explanation

[0030] 23: Cylinder head 31: Intake valve 33: Exhaust valve 35a: Intake rocker arm (rocker) 35b: Intake rocker arm (rocker) 37: Exhaust rocker arm (rocker) 40: Variable valve device 41: Camshaft 42a: Cam housing 42b: Cam housing 47: Intake rocker arm shaft (rocker shaft) 48: Exhaust rocker arm shaft (rocker shaft) 49: Upper housing 50: Switching mechanism 93c: Lubrication groove 93e: Lubrication passage (third lubrication passage) 93i: Lubrication passage (first lubrication passage) 93o: Lubrication passage (fourth lubrication passage) 93s: Lubrication passage (second lubrication passage) 94b: Injection hole (first injection hole) 94c: Injection hole (third injection hole) 94d: Injection hole (fourth injection hole) 94f: Injection hole (second injection hole). Detailed Description of the Invention

[0031] A variable valve device according to one aspect of the present invention changes the valve operation in a cylinder head. Inside the cylinder head, a pair of cam housings are separated in a predetermined direction, and a camshaft is supported by the cylinder head and the pair of cam housings. An upper housing is supported on the upper surfaces of the pair of cam housings in a manner supported at both ends. A rocker shaft is supported at a relative portion of the pair of cam housings, and a plurality of rockers are supported on the rocker shaft so as to be swingable. An intake arm among the plurality of rockers is connected and separated by a switching mechanism. A first injection hole for supplying lubricating oil to the switching mechanism and a second injection hole for supplying lubricating oil to the plurality of rockers are formed in the upper housing, and the lubricating oil is pressed from a lubricating groove around the camshaft toward the first injection hole and the second injection hole. The passage length from the lubricating groove around the camshaft to the second injection hole is longer than the passage length from the lubricating groove to the first injection hole, and the hydraulic pressure of the lubricating passage connected to the first injection hole on the switching mechanism side is increased. Even if the components to be lubricated increase due to the switching mechanism, an appropriate amount of lubricating oil is supplied from the first injection hole to the switching mechanism, and an appropriate amount of lubricating oil is supplied from the second injection hole to the plurality of rockers. Therefore, each component of the switching mechanism and the plurality of rockers is appropriately lubricated.

[0032] Embodiment

[0033] Hereinafter, this embodiment will be described in detail with reference to the drawings. Figure 1 is a right side view of the engine and the body frame of this embodiment. Figure 2 is a right side view of the upper part of the engine after removing the cylinder head cover of this embodiment. Figure 3 is a perspective view of the upper part of the engine after removing the cylinder head cover of this embodiment. Figure 4 is a schematic plan view of the variable valve device of this embodiment. In addition, in the following figures, the arrow FR indicates the front of the vehicle, the arrow RE indicates the rear of the vehicle, the arrow L indicates the left side of the vehicle, and the arrow R indicates the right side of the vehicle. In addition, Figure 3 is described with the oil control valve omitted.

[0034] As Figure 1 shown, a straddle-type vehicle is configured by mounting various components such as an engine 20 and an electrical system on a cradle-type body frame 10. The body frame 10 has: a main pipe 12 that extends rearward from the upper part of the head pipe 11 and then bends downward; and a lower pipe 13 that extends downward from the lower part of the head pipe 11 and then bends rearward. The rear end portion of the lower pipe 13 is joined to the lower end portion of the main pipe 12, so that a mounting space for the engine 20 is formed inside the body frame 10. The rear side of the engine 20 is supported by the main pipe 12, and the front side and the lower side of the engine 20 are supported by the lower pipe 13.

[0035] The engine 20 has a crankcase 21, a cylinder 22 provided on the crankcase 21, a cylinder head 23 provided on the cylinder 22, and a cylinder head cover 24 provided on the cylinder head 23. A clutch cover 25 that laterally covers a clutch (not shown) is mounted on the right side surface of the crankcase 21. A magnet cover (not shown) that laterally covers a magnet (not shown) is mounted on the left side surface of the crankcase 21. An oil pan 26 for storing oil is mounted on the lower surface of the crankcase 21.

[0036] As Figure 2 and Figure 3 shown, the engine 20 is a four-valve twin-cylinder engine, and a cam chain 27 is provided in the middle of the two cylinders. The cam chain 27 is wound around a cam sprocket 28, and variable valve devices 40 are provided for each of the left and right cylinders with the cam sprocket 28 interposed therebetween. A camshaft 41 that rotates integrally with the cam sprocket 28 is provided in the variable valve device 40. In the cylinder head 23, cam housings 42a, 42b are separately provided for each cylinder in the left-right direction (predetermined direction), and the camshaft 41 is supported rotatably by the mating surfaces of the cam housings 42a, 42b and the cylinder head 23.

[0037] In the cylinder head 23, four intake valves 31 are provided on the rear side of the camshaft 41, and four exhaust valves 33 are provided on the front side of the camshaft 41. The intake valves 31 are pressed in the valve closing direction by valve springs 32, and the exhaust valves 33 are pressed in the valve closing direction by valve springs 34. On the outer peripheral surface of the camshaft 41, a low-speed cam 44, a high-speed cam 45, and an exhaust cam 46 (all refer to Figure 4 ) are formed. Each of the cams 44 to 46 is formed in a plate shape in which a cam tip projects from a part of the base circle. The cam tip of the high-speed cam 45 is higher than the cam tip of the low-speed cam 44 so that the valve lift amount of the high-speed cam 45 is larger than that of the low-speed cam 44.

[0038] An intake rocker arm shaft 47 and an exhaust rocker arm shaft 48 are supported at opposite portions of the cam housings 42a, 42b. The intake rocker arm shaft 47 and the exhaust rocker arm shaft 48 are located above the camshaft 41 and extend parallel to the camshaft 41. An upper housing 49 is supported on the upper surface of the cam housings 42a, 42b in a manner supported at both ends, and a hydraulic piston 53 and a spring pin 54 (refer to Figure 4 ) are housed in the upper housing 49. An oil control valve 60 (not shown in Figure 3 ) is provided on the rear side of the upper surface of the cylinder head cover 24.

[0039] As Figure 4 shown, the intake rocker arm shaft 47 is located on the rear side of the camshaft 41, and the exhaust rocker arm shaft 48 is located on the front side of the camshaft 41. Two types of intake rocker arms 35a, 35b are supported on the intake rocker arm shaft 47 so as to be swingable (in Figure 4Only one is shown respectively in )), and an exhaust rocker arm 37 is swingably supported on an exhaust rocker arm shaft 48 (only one is shown in Figure 4 ). The intake rocker arm 35a and the exhaust rocker arm 37 are formed in a seesaw shape having a force point and a point of action, but the intake rocker arm 35b is formed as the force point of the intake rocker arm 35a.

[0040] A roller 36a that rolls in contact with a low-speed cam 44 is rotatably supported at one end of the intake rocker arm 35a, and a pair of intake valves 31 are connected to the other end of the intake rocker arm 35a that branches into two. A roller 36b that rolls in contact with a high-speed cam 45 is rotatably supported at one end of the intake rocker arm 35b, and no intake valve 31 is connected to the other end of the intake rocker arm 35b. A roller 38 that rolls in contact with an exhaust cam 46 is rotatably supported at one end of the exhaust rocker arm 37, and a pair of exhaust valves 33 are connected to the other end of the exhaust rocker arm 37 that branches into two. The intake rocker arms 35a and 35b are formed to be connectable.

[0041] When the engine is rotating at a low speed and a medium speed, the intake rocker arms 35a and 35b are not connected. Therefore, the intake rocker arm 35a is swung by the low-speed cam 44, and the intake rocker arm 35b is swung by the high-speed cam 45. Since a pair of intake valves 31 are connected to the intake rocker arm 35a, the pair of intake valves 31 move according to the rotation of the low-speed cam 44. Since the cam tip of the low-speed cam 44 is low, the valve lift amount of the pair of intake valves 31 becomes low. In addition, since no intake valve 31 is connected to the intake rocker arm 35b, the intake rocker arm 35b swings idly according to the rotation of the high-speed cam 45.

[0042] When the engine is rotating at a high speed, the intake rocker arms 35a and 35b are connected. Therefore, the intake rocker arms 35a and 35b are swung integrally by the high-speed cam 45. A pair of intake valves 31 are connected to the intake rocker arm 35b via the intake rocker arm 35a, so the pair of intake valves 31 move according to the rotation of the high-speed cam 45. Since the cam tip of the high-speed cam 45 is high, the valve lift amount of the pair of intake valves 31 becomes high. In this way, by switching the connection state of the intake rocker arms 35a and 35b, the low-speed cam 44 and the high-speed cam 45 that move the intake valves 31 are switched.

[0043] A switching mechanism 50 for connecting and disconnecting the intake rocker arms 35a and 35b is provided in each variable valve device 40. A connecting pin 51 provided in the receiving chamber of the intake rocker arm 35b and a return pin 52 provided in the receiving chamber of the intake rocker arm 35a are provided in the switching mechanism 50. In addition, a hydraulic piston 53 that contacts the connecting pin 51 from one side in the left-right direction and a spring pin 54 that contacts the return pin 52 from the other side in the left-right direction are provided in the switching mechanism 50. The hydraulic piston 53 is formed to be able to advance and retreat by hydraulic pressure, and the spring pin 54 is formed to be able to advance and retreat by the expansion and contraction of a spring.

[0044] When working oil is supplied to the hydraulic piston 53, the hydraulic piston 53 advances against the spring force of the spring pin 54. Due to the advancement of the hydraulic piston 53, the return pin 52 is pressed into the connecting pin 51, and a part of the connecting pin 51 enters the receiving chamber of the intake rocker arm 35a from the receiving chamber of the intake rocker arm 35b to connect the intake rocker arms 35a and 35b. When the working oil is discharged from the hydraulic piston 53, due to the spring force of the spring pin 54, the hydraulic piston 53 retreats. Due to the retreat of the hydraulic piston 53, the connecting pin 51 is pushed back by the return pin 52, so that a part of the connecting pin 51 is withdrawn from the receiving chamber of the intake rocker arm 35a to separate the intake rocker arms 35a and 35b.

[0045] In addition, lubricating oil is supplied from the crankcase 21 toward the variable valve device 40 through the gap between the head bolts and the bolt holes. In the variable valve device 40, the lubricating oil is pressed toward each lubrication target through the lubrication groove around the camshaft 41. Injection holes that open to the atmosphere for each component to be lubricated are formed in the upper housing 49. The lubrication passage extends in two directions from the lubrication groove, and the lubricating oil is transported to the injection holes for the rod end of the intake valve 31 and the switching mechanism 50 through one lubrication passage, and the lubricating oil is transported to the injection holes for the rod end of the exhaust valve 33 and the rocker arms 35a, 35b, 37 through the other lubrication passage.

[0046] At this time, two injection holes for the rod end of the intake valve 31 and five injection holes for the switching mechanism 50 are provided in one lubrication passage. Two injection holes for the rod end of the intake valve 31 and three injection holes for the rocker arms 35a, 35b, 37 are provided in the other lubrication passage. Since these injection holes are formed to have the same diameter, the total area of the injection holes that open to the atmosphere in one lubrication passage is larger than the total area of the injection holes that open to the atmosphere in the other lubrication passage. In addition, in one lubrication passage, injection holes for the rod end of the intake valve 31 and injection holes for the switching mechanism 50 are formed at the highest position H1 (refer to Figure 2 ) in a side view.

[0047] Therefore, if the passage length of the lubrication passage of one party is substantially the same as that of the lubrication passage of the other party, or the passage length of the lubrication passage of one party is longer than that of the lubrication passage of the other party, the hydraulic pressure in the lubrication passage of one party becomes lower. Moreover, the supply amount of the lubricating oil from the rod end of the intake valve 31 and the injection holes for the switching mechanism 50 decreases. Especially at high oil temperatures and low rotations, the lubricating oil does not spray from the injection holes and it becomes impossible to properly lubricate each component. Therefore, in the present embodiment, the lubrication passage in the camshaft 41 is used to make the passage length of the lubrication passage of the other party longer, thereby increasing the hydraulic pressure in the lubrication passage of one party and properly lubricating the rod end of the intake valve 31 and the switching mechanism 50.

[0048] Refer to Figure 5 to describe the variable valve device. Figure 5 is a schematic diagram of the variable valve device of the present embodiment.

[0049] As Figure 5 shown, in the variable valve device 40, the oil supply passage 55 extends from the oil pan 26 toward the oil control valve 60. The oil pump 56 in the middle of the oil supply passage 55 sucks the oil from the oil pan 26, and after passing through the oil filter 57, supplies the oil to the oil control valve 60. The oil control valve 60 is formed by a valve housing 61 that houses a valve element (not shown) and a solenoid 62 that moves the valve element forward and backward. By moving the valve element by the solenoid 62, the oil passage in the oil control valve 60 is switched.

[0050] An input port 63, a low-speed port 64, a high-speed port 65, and a discharge port 66 are formed in the valve housing 61. The oil supply passage 55 communicates with the input port 63, the dead-end passage 67 communicates with the low-speed port 64, the switching passage 69 communicates with the high-speed port 65, and the discharge passage 68 communicates with the discharge port 66. The output destination of the dead-end passage 67 is blocked, and the switching passage 69 extends from the oil control valve 60 toward the switching mechanism 50. The discharge passage 68 extends from the oil control valve 60 to above the oil pan 26, and causes the oil to fall from the outlet of the discharge passage 68 to the oil pan 26.

[0051] By moving the valve element of the oil control valve 60, the input port 63 communicates with either the low-speed port 64 or the high-speed port 65, and the discharge port 66 communicates with the other of the low-speed port 64 and the high-speed port 65. The oil is output from the oil control valve 60 to either the dead-end passage 67 or the switching passage 69, and the remaining oil is discharged from the other of the dead-end passage 67 and the switching passage 69 to the oil control valve 60 (discharge passage 68). In this way, the hydraulic pressure for the switching mechanism 50 is controlled by the oil control valve 60.

[0052] The switching passage 69 is divided into a working passage 71 and a direct passage 74. Both the working passage 71 and the direct passage 74 extend from the oil control valve 60 to the hydraulic piston 53 of the switching mechanism 50. A part of the working passage 71 is formed by an oil groove 73 that allows oil to pass through at a specified rotational phase of the camshaft 41. As described above, the camshaft 41 is formed with a low-speed cam 44, a high-speed cam 45, and an exhaust cam 46 (not shown in Figure 6 ), and the oil groove 73 is locally formed on the outer peripheral surface of the camshaft 41.

[0053] The working passage 71 is divided into an upstream passage 72a and a downstream passage 72b across the oil groove 73 of the camshaft 41. With the rotation of the camshaft 41, the connection and disconnection between the upstream passage 72a and the downstream passage 72b of the working passage 71 are alternately repeated. The direct passage 74 extends directly from the oil control valve 60 to the hydraulic piston 53 without passing through the oil groove 73 of the camshaft 41. After the hydraulic piston 53 is moved as a trigger by the oil supply via the working passage 71, the hydraulic piston 53 is held in the pushed-out state by the oil supply via the direct passage 74. In addition, the specified rotational phase of the camshaft 41 is set during the period from the end moment of valve lift to before the start of the next valve lift.

[0054] A connecting pin 51 is provided in the receiving hole at the upper part of the intake rocker arm 35b, and a return pin 52 is provided in the receiving hole at the upper part of the intake rocker arm 35a. The tip of the return pin 52 contacts the tip of the connecting pin 51. A hydraulic chamber 87 and a receiving chamber 88 are formed in the upper housing 49. A hydraulic piston 53 is provided in the hydraulic chamber 87, and a spring pin 54 is provided in the receiving chamber 88. The pressing surface of the hydraulic piston 53 contacts the connecting pin 51, and the pressing surface of the spring pin 54 contacts the return pin 52. In addition, a sensing arm 78 extends from the spring pin 54 to the other side.

[0055] The switching mechanism 50 moves the connecting pin 51 hydraulically to switch the connection state of the intake rocker arms 35a and 35b. As described above, in the separated state of the intake rocker arms 35a and 35b, a pair of intake valves 31 are operated via the intake rocker arm 35a by the low-speed cam 44. In the connected state of the intake rocker arms 35a and 35b, a pair of intake valves 31 are operated via the intake rocker arms 35a and 35b by the high-speed cam 45. Thus, in the switching mechanism 50, by switching the connection state of the intake rocker arms 35a and 35b using the connecting pin 51, the cam that moves a pair of intake valves 31 is switched.

[0056] In addition, an ECM (Engine Control Module) 75, an engine angle sensor 76, and a switching sensor 77 are provided in the variable valve device 40. The engine speed is detected by the engine angle sensor 76. When the engine speed reaches a specified speed or higher, a connection command signal is output from the ECM 75 to the solenoid 62. When the engine speed is lower than the specified speed, a release command signal is output from the ECM 75 to the solenoid 62. The switching sensor 77 detects the switching between the connected state and the separated state of the intake rocker arms 35a and 35b based on the movement of the tip of the sensing arm 78. The command signal from the ECM 75 is compared with the detection signal from the switching sensor 77 to determine a failure of the variable valve device 40 such as a defective switching operation.

[0057] Hereinafter, Figures 6 to 16 the oil passages for lubrication and operation will be described. Figure 6 are a top view and a bottom view of the upper housing of the present embodiment. Figure 7 is a top view inside the cylinder head of the present embodiment. Figure 8 is to Figure 7 a cross-sectional view of the cylinder head taken along line A-A. Figure 9 is to Figure 8 a cross-sectional view of the cylinder head taken along line B-B. Figure 10 is to Figure 7 a cross-sectional view of the cylinder head taken along line C-C. Figure 11 is to Figure 7 a cross-sectional view of the cylinder head taken along line D-D. Figure 12 is to Figure 7 a cross-sectional view of the cylinder head taken along line E-E. Figure 13 is to Figure 8 a cross-sectional view of the cylinder head taken along line F-F. Figure 14 is to Figure 13 a cross-sectional view of the cylinder head taken along line G-G. Figure 15 is to Figure 7 a cross-sectional view of the cylinder head taken along line H-H. Figure 16 is to Figure 7 a cross-sectional view of the cylinder head taken along line I-I.

[0058] As Figure 6 (A) and (B) show, the upper housing 49 is formed in a trapezoidal shape by the housing fixing portions 81a and 81b extending in the front-rear direction and the first to third bridge portions 82 to 84 extending in the left-right direction. The housing fixing portions 81a and 81b are fixed to the cam housings 42a and 42b (see Figure 3)。The first bridge portion 82 connects the housing fixing portions 81a and 81b on the intake side of the cylinder head 23. The second bridge portion 83 connects the housing fixing portions 81a and 81b at the middle between the intake side and the exhaust side of the cylinder head 23. The third bridge portion 84 connects the housing fixing portions 81a and 81b on the exhaust side of the cylinder head 23.

[0059] The first bridge portion 82 extends along the intake rocker shaft 47 (refer to Figure 3 ), and a lubrication passage 93i for lubricating oil to pass through is formed in the first bridge portion 82 (refer to Figure 11 ). A plurality of (five in this embodiment) injection holes 94b are formed on the lower surface of the first bridge portion 82, and the plurality of injection holes 94b are located above the contact portions between the components of the switching mechanism 50. A pair of nozzles 91 protrude from the first bridge portion 82 toward the intake side, and the injection holes 94c at the tips of the pair of nozzles 91 are located above a pair of intake valves 31 (refer to Figure 3 ). The first bridge portion 82 is connected to the housing fixing portions 81a and 81b via connection portions 86a and 86b.

[0060] A hydraulic chamber 87 is formed at the connection portion 86a which is the connection portion between the first bridge portion 82 and the housing fixing portion 81a (refer to Figure 5 ). A housing chamber 88 is formed at the connection portion 86b which is the connection portion between the first bridge portion 82 and the housing fixing portion 81b (refer to Figure 5 ). A hydraulic piston 53 is provided in the hydraulic chamber 87 (refer to Figure 5 ), and a spring pin 54 is provided in the housing chamber 88 (refer to Figure 5 ). The hydraulic chamber 87 and the housing chamber 88 are formed coaxially, ensuring the parallelism between the hydraulic piston 53 and the spring pin 54. Working oil is supplied to the hydraulic chamber 87 through a hydraulic circuit different from the lubricating oil.

[0061] The second bridge portion 83 extends along the camshaft 41 (refer to Figure 3 ), and a lubrication passage 93s is formed in the second bridge portion 83 (refer to Figure 16 ). A plurality of injection holes 94f are formed on the lower surface of the second bridge portion 83, and the plurality of injection holes 94f are located above the rockers 35a, 35b, and 37. The third bridge portion 84 extends along the exhaust rocker shaft 48 (refer to Figure 3 ). A pair of nozzles 92 protrude from the third bridge portion 84 toward the exhaust side, and the injection holes 94d at the tips of the pair of nozzles 92 are located above a pair of exhaust valves 33 (refer to Figure 3 ).

[0062] An oil hole 89 is formed on the intake side of the housing fixing portion 81a, and working oil is supplied from the oil control valve 60 to the oil hole 89. An oil groove is formed on the lower surface of the housing fixing portion 81a. By fixing the housing fixing portion 81a to the cam housing 42a, a working passage 71 and a direct passage 74 for the working oil to pass through are formed. The working passage 71 and the direct passage 74 communicate with the hydraulic chamber 87 provided with the hydraulic piston 53, and working oil is supplied from the oil control valve 60 to the hydraulic chamber 87 through the working passage 71 and the direct passage 74.

[0063] An oil groove is formed on the lower surface of the housing fixing portion 81a. By fixing the housing fixing portion 81a to the cam housing 42a, a lubrication passage 93q is formed. Lubricating oil is sent from the lubrication passage 93q to the lubrication passage 93s of the second bridge portion 83. An oil groove is formed on the lower surface of the housing fixing portion 81b. By fixing the housing fixing portion 81b to the cam housing 42b, a lubrication passage 93g is formed. Lubricating oil is sent from the lubrication passage 93g to the lubrication passage 93i of the first bridge portion 82. In this way, a hydraulic circuit for lubricating oil and working oil is formed in the upper housing 49.

[0064] As Figures 7 to 9 shown, the cylinder head 23 is fixed to the crankcase 21 via the cylinder 22 by a plurality of head bolts 79. The clearance between the exhaust-side bolt 79 and the bolt hole is the lubrication passage 93a, and the lubrication passage 93b extends obliquely from the lubrication passage 93a to the camshaft 41. Lubricating oil is guided from the crankcase 21 to the lubrication groove 93c around the camshaft 41 through the lubrication passages 93a and 93b. The lubrication groove 93c around the camshaft 41 is divided into a lubrication path 90a leading to the switching mechanism 50 and a lubrication path 90b leading to the rocker arms 35a, 35b, and 37.

[0065] First, the lubrication path 90a will be described. The housing fixing portion 81a on the central side in the left-right direction is fixed to the cylinder head 23 via the cam housing 42a by a pair of housing bolts 95a. The clearance between the intake-side housing bolt 95a and the bolt hole is the lubrication passage 93d extending from the lubrication groove 93c around the camshaft 41 to the intake rocker arm shaft 47. Lubricating oil is guided from the lubrication passage 93d to the lubrication passage 93e in the intake rocker arm shaft 47, and the lubricating oil flows from one end to the other end of the lubrication passage 93e. A plurality of supply holes 94a are provided in the lubrication passage 93e in the intake rocker arm shaft 47, and lubricating oil is supplied from the supply holes 94a to the shaft holes of the intake rocker arms 35a and 35b. In addition, the supply holes 94a are not open to the atmosphere.

[0066] As Figure 7 and Figure 10As shown, the outer housing fixing portions 81b on the left - right direction are fixed to the cylinder head 23 via the cam housing 42b by a pair of housing bolts 95b. The clearance between the intake - side housing bolt 95b and the bolt hole is a lubrication passage 93f that extends from the end of the lubrication passage 93e of the intake rocker shaft 47 to the housing fixing portion 81b. The lubrication passage 93h extends obliquely from the lubrication passage 93g on the mating surface of the housing fixing portion 81b and the cam housing 42b toward the first bridge portion 82. A lubrication passage 93i is formed in the first bridge portion 82, and lubricating oil is guided from the lubrication passage 93h to the lubrication passage 93i, and the lubricating oil flows from the other end to one end of the lubrication passage 93i.

[0067] As Figure 7 and Figure 11 shown, five injection holes 94b that open to the atmosphere are provided in the lubrication passage 93i. Each injection hole 94b is positioned above the contact portions of the hydraulic piston 53, the connecting pin 51, the return pin 52, and the spring pin 54. Lubricating oil is injected from each injection hole 94b to the contact portions between the components. As Figure 7 and Figure 12 shown, a pair of nozzles 91 project from the first bridge portion 82 toward the intake side, and injection holes 94c that open to the atmosphere are formed in each nozzle 91. Each injection hole 94c faces the inner wall surface of the cylinder head cover 24, and the lubricating oil blown from each injection hole 94c to the inner wall surface is supplied along the inner wall surface to the rod ends of the pair of intake valves 31.

[0068] Next, the lubrication path 90b will be described. As Figure 8 and Figure 13 shown, below the cam housing 42a on the central side in the left - right direction, the lubrication passage 93j extends from the lubrication groove 93c around the camshaft 41 toward the inside of the camshaft 41. Lubricating oil is guided from the lubrication passage 93j to the lubrication passage 93k inside the camshaft 41, and the lubricating oil flows from the center in the left - right direction of the lubrication passage 93k to the outside in the left - right direction. An outlet of the lubrication passage 93j is provided on the central side in the left - right direction of the lubrication passage 93k below the cam housing 42a, and an inlet of the lubrication passage 93l is provided on the outer side in the left - right direction of the lubrication passage 93k below the cam housing 42b.

[0069] As Figure 13 、 Figure 14 shown, below the cam housing 42b on the outer side in the left - right direction, lubricating oil is guided from the lubrication passage 93l to the lubrication groove 93m around the camshaft 41. The clearance between the exhaust - side housing bolt 95b and the bolt hole is a lubrication passage 93n that extends from the lubrication groove 93m around the camshaft 41 to the exhaust rocker shaft 48. A pair of nozzles 92 (especially refer to Figure 7)It protrudes from the third bridge portion 84, and injection holes 94d that are connected to the lubrication passage 93n and open to the atmosphere are formed in each nozzle 92. Each injection hole 94d faces the rib 96 of the cylinder head cover 24 (refer to Figure 12 ), and the lubricating oil sprayed from each injection hole 94d onto the rib 96 is supplied to the rod ends of the pair of exhaust valves 33 along the rib 96.

[0070] As Figure 9 and Figure 14 show, the lubricating oil is guided from the lubrication passage 93n to the lubrication passage 93o in the exhaust rocker arm shaft 48, and the lubricating oil flows from the other end to one end of the lubrication passage 93o. A plurality of supply holes 94e are provided in the lubrication passage 93o in the exhaust rocker arm shaft 48, and the lubricating oil is supplied from the supply holes 94e to the shaft holes of the exhaust rocker arms 37. In addition, the supply holes 94e do not open to the atmosphere. In this way, the lubrication path 90b is folded back by the lubrication passage 93k in the camshaft 41 and the lubrication passage 93o in the exhaust rocker arm shaft 48. In addition, the clearance between the exhaust-side housing bolt 95a on the outlet side of the lubrication passage 93o and the bolt hole is the lubrication passage 93p (refer to Figure 15 ).

[0071] As Figure 15 and Figure 16 show, the lubrication passage 93r extends obliquely from the lubrication passage 93q on the mating surface of the housing fixing portion 81a and the cam housing 42a toward the second bridge portion 83. The lubricating oil is guided from the lubrication passage 93r to the lubrication passage 93s in the second bridge portion 83, and the lubricating oil flows from one end to the other end of the lubrication passage 93s. Three injection holes 94f that open to the atmosphere are provided in the lubrication passage 93s. Each injection hole 94f is positioned above the intake rocker arms 35a, 35b and the exhaust rocker arm 37. The lubricating oil is sprayed from each injection hole 94f onto each rocker arm 35a, 35b, 37.

[0072] In this way, the lubricating oil is pressed from the lubrication groove 93c around the camshaft 41 toward each injection hole 94b~94d, 94f. The lubrication path 90a flows from the lubrication groove 93c through the lubrication passages 93d~93i to the injection holes 94b, 94c. In addition, after the lubrication path 90b passes through the lubrication groove 93m from the lubrication groove 93c through the lubrication passages 93j, 93k, the lubrication path 90b flows from the lubrication groove 93m through the lubrication passages 93n~93s to the injection holes 94d, 94f. The passage length from the lubrication groove 93c of the lubrication path 90b to the injection hole 94f is formed to be longer than the passage length from the lubrication groove 93c of the lubrication path 90a to the injection holes 94b, 94c, thereby increasing the hydraulic pressure of the lubrication passages 93i, the injection holes 94b, 94c.

[0073] As described above, five injection holes 94b for the switching mechanism 50, two injection holes 94c for the rod end of the intake valve 31, two injection holes 94d for the rod end of the exhaust valve 33, and three injection holes 94f for the rocker arms 35a, 35b, and 37 are formed in the upper housing 49. The number of injection holes 94b and 94c in the lubrication path 90a is formed to be larger than the number of injection holes 94d and 94f in the lubrication path 90b. By reducing the number of injection holes 94d and 94f on the lubrication path 90b side, the supply amount of lubricating oil to the injection hole 94b of the switching mechanism 50 with more lubrication parts on the lubrication path 90a side can be increased.

[0074] All the injection holes 94b to 94d and 94f of the upper housing 49 are formed to have the same diameter, so that it is easy to machine the injection holes 94b to 94d and 94f in the upper housing 49. In addition, it is easy to adjust the supply amount of lubricating oil on the lubrication path 90a and 90b sides according to the passage length. The injection holes 94b and 94c are provided on the same lubrication passage 93i, so that the injection holes 94b and 94c are compactly provided on the intake side of the engine 20. An injection hole 94d is provided in the lubrication passage 93o upstream of the injection hole 94f, and the supply amount of lubricating oil from the injection hole 94f to the rocker arms 35a, 35b, and 37 is adjusted by the position of the injection hole 94d.

[0075] The lubrication passage 93e in the intake rocker shaft 47 is connected in series with the lubrication passage 93i in the first bridge portion 82, and the lubricating oil flows from the lubrication groove 93c through the lubrication passages 93e and 93i and toward the injection holes 94b and 94c in one direction. The lubrication passage 93o in the exhaust rocker shaft 48 is connected in series with the lubrication passage 93s in the second bridge portion 83, and the lubricating oil flows through the lubrication passages 93o and 93s and toward the injection holes 94d and 94f in one direction. By making the flow of the lubricating oil in the lubrication paths 90a and 90b be in one direction respectively, the branching of the passage is reduced and it is easy to control the amount of lubricating oil.

[0076] The lubrication passage 93i is located above the lubrication passage 93e, and the lubrication passage 93s is located above the lubrication passage 93o. Even if the number of passages increases, the lubrication passages are compactly gathered. As Figure 2 shown, the lubrication passage 93i is positioned at the highest position H1, the lubrication passage 93s is positioned at the second highest position H2, the lubrication passage 93e is positioned at the third highest position H3, and the lubrication passage 93o is positioned at the lowest position H4. The injection hole 94b in the lubrication passage 93i is positioned higher than the injection hole 94f in the lubrication passage 93s. Even if the switching mechanism 50 is positioned relatively high, the switching mechanism 50 can be properly injected by the injection of the lubricating oil from the injection hole 94b.

[0077] As described above, in the variable valve device 40 according to the present embodiment, the passage length from the lubrication groove 93c around the camshaft 41 to the injection holes 94f for the rocker arms 35a, 35b, 37 is longer than the passage length from the lubrication groove 93c to the injection hole 94b for the switching mechanism 50. Therefore, the hydraulic pressure of the lubrication passage provided with the injection hole 94b increases. Even if the components to be lubricated increase due to the switching mechanism 50, an appropriate amount of lubricating oil is injected from the injection hole 94b to the switching mechanism 50, and an appropriate amount of lubricating oil is injected from the injection hole 94f to each of the rocker arms 35a, 35b, 37. Therefore, each component of the switching mechanism 50 and each of the rocker arms 35a, 35b, 37 is appropriately lubricated.

[0078] In addition, in the present embodiment, the variable valve device is provided with a pair of intake rocker arms, but the variable valve device may be provided with three or more intake rocker arms.

[0079] Further, in the present embodiment, five injection holes for the switching mechanism are formed in the upper housing, and three injection holes for the rocker arms are formed. Each injection hole is formed to have the same diameter. However, as long as the total area of the injection holes for the switching mechanism is larger than the total area of the injection holes for the rocker arms, the number and size of the injection holes are not limited.

[0080] In addition, in the present embodiment, although the upper housing has the first bridge portion to the third bridge portion, the upper housing only needs to be formed so as to be able to be supported at both ends on the upper surfaces of a pair of cam housings.

[0081] In addition, in the present embodiment, a seesaw-type rocker arm is illustrated, but the type of the rocker arm is not particularly limited, and a finger follower-type rocker arm may also be used.

[0082] In addition, in the present embodiment, a plurality of rocker arms are adjacent to each other, but the plurality of rocker arms may also be separated.

[0083] In addition, the exhaust device of the present embodiment is not limited to the engine of the above-described straddle-type vehicle, and may also be applied to the engines of other transportation means. In addition, the straddle-type vehicle is not limited to a motorcycle, and any transportation means equipped with an engine may be used. In addition, the so-called straddle-type vehicle does not limit all vehicles in which the driver rides in a posture of straddling the seat, and also includes a step-type vehicle in which the driver rides without straddling the seat.

[0084] As described above, the first mode is a variable valve device 40 capable of changing valve operation in the cylinder head 23. The variable valve device 40 includes: a pair of cam housings 42a and 42b that are separated in a specified direction within the cylinder head; a camshaft 41 supported by the cylinder head and the pair of cam housings; a pair of rocker shafts (intake rocker shaft 47 and exhaust rocker shaft 48) supported at opposing portions of the pair of cam housings; a plurality of rockers (intake rockers 35a and 35b and exhaust rocker 37) swingably supported by the pair of rocker shafts; a switching mechanism 50 that connects and disconnects the intake arms of the plurality of rockers; and an upper housing 49 supported at both ends on the upper surfaces of the pair of cam housings. A first injection hole (injection hole 94b) for supplying lubricating oil to the switching mechanism and a second injection hole (injection hole 94f) for supplying lubricating oil to the plurality of rockers are formed in the upper housing. The lubricating oil is pressured from a lubricating groove (93c) around the camshaft toward the first injection hole and the second injection hole, and the passage length from the lubricating groove to the second injection hole is formed to be longer than the passage length from the lubricating groove to the first injection hole. According to this structure, since the passage length from the lubricating groove around the camshaft to the second injection hole is longer than the passage length from the lubricating groove to the first injection hole, the hydraulic pressure of the lubricating passage provided with the first injection hole on the switching mechanism side increases. Even if the number of components of the lubrication target increases due to the switching mechanism, an appropriate amount of lubricating oil is injected from the first injection hole to the switching mechanism, and an appropriate amount of lubricating oil is injected from the second injection hole to the plurality of rockers. Therefore, each component of the switching mechanism and the plurality of rockers is appropriately lubricated.

[0085] In the second mode, in the first mode, the pair of rocker shafts are the intake rocker shaft and the exhaust rocker shaft. The lubricating oil is pressured from the lubricating groove through the intake rocker shaft to the first injection hole, and the lubricating oil passes through the camshaft and then through the exhaust rocker shaft and is pressured to the second injection hole. According to this structure, by making the existing components of the intake rocker shaft, the exhaust rocker shaft, and the camshaft into lubricating passages, the passage length can be easily adjusted.

[0086] In the third mode, in the first mode or the second mode, more first injection holes than the second injection hole are formed in the upper housing. According to this structure, by reducing the second injection holes on the rocker side, the supply amount of lubricating oil to the first injection holes of the switching mechanism with more lubrication parts can be increased.

[0087] The fourth method is that, in any one of the first to third methods, a third injection hole (injection hole 94c) for supplying lubricating oil to the rod end of the intake valve 31 and a fourth injection hole (injection hole 94d) for supplying lubricating oil to the rod end of the exhaust valve 33 are formed in the upper housing. The first injection hole and the third injection hole are provided in the same lubrication passage, and the fourth injection hole is provided in the lubrication passage upstream of the second injection hole. According to this structure, the first injection hole and the third injection hole can be formed compactly in the same lubrication passage, and the supply amount of the lubricating oil from the second injection hole to the rocker arm can be adjusted by the position of the fourth injection hole.

[0088] The fifth method is that, in any one of the first to fourth methods, the first injection hole and the second injection hole are formed to have the same diameter. According to this structure, it is easy to adjust the supply amount of the lubricating oil according to the passage length. In addition, it is easy to machine the injection holes in the upper housing.

[0089] The sixth method is that, in any one of the first to fifth methods, the first injection hole is positioned higher than the second injection hole. According to this structure, even if the switching mechanism is positioned higher, the switching mechanism can be properly lubricated by the injection of the lubricating oil from the first injection hole.

[0090] The seventh method is that, in any one of the first to sixth methods, the pair of rocker shafts are an intake rocker shaft and an exhaust rocker shaft. A first lubrication passage (lubrication passage 93i) provided with the first injection hole and a second lubrication passage (lubrication passage 93s) provided with the second injection hole are formed in the upper housing. A third lubrication passage (lubrication passage 93e) connected in series with the first lubrication passage is formed in the intake rocker shaft, and a fourth lubrication passage (lubrication passage 93o) connected in series with the second lubrication passage is formed in the exhaust rocker shaft. The first lubrication passage is located above the third lubrication passage, and the second lubrication passage is located above the fourth lubrication passage. According to this structure, even if the number of passages increases, the lubrication passages can be compactly gathered. By connecting the first lubrication passage and the third lubrication passage in series and connecting the second lubrication passage and the fourth lubrication passage in series, the lubricating oil flows from the lubricating groove in one direction toward the first supply hole and the second supply hole respectively, and it is easy to control the amount of the lubricating oil.

[0091] In addition, although this embodiment has been described, as other embodiments, the above embodiments and modification examples can also be combined in whole or in part.

[0092] In addition, the technology of the present invention is not limited to the above embodiments, and various changes, substitutions, and deformations can also be made without departing from the gist of the technical idea. Moreover, if the technical idea can be implemented in other ways through technological progress or other derived technologies, such methods can also be used for implementation. Therefore, the scope of protection claimed by the present invention covers all embodiments that can be included within the scope of the technical idea.

Claims

1. A variable valve device capable of changing valve motion in a cylinder head, characterized in that: have: a pair of cam housings separated in a specified direction within the cylinder head; a camshaft supported by the cylinder head and the pair of cam housings; a pair of rocker arm shafts, the pair of rocker arm shafts being supported at opposite positions of the pair of cam housings; a plurality of rocker arms supported on the pair of rocker arm shafts in a swingable manner; a switching mechanism that connects and disconnects the intake arms of the plurality of rocker arms; and an upper housing supported at both ends on the upper surfaces of the pair of cam housings, The upper housing is formed with a first injection hole for supplying lubricating oil to the switching mechanism and a second injection hole for supplying lubricating oil to the plurality of rocker arms. Lubricating oil is pressure-fed from a lubricating groove around the camshaft toward the first and second injection holes, and a passage length from the lubricating groove to the second injection hole is longer than a passage length from the lubricating groove to the first injection hole.

2. The variable valve device according to claim 1, characterized in that: The pair of rocker arm shafts are an intake rocker arm shaft and an exhaust rocker arm shaft, The lubricating oil is pressed from the lubrication groove through the intake rocker arm shaft to the first injection hole. The lubricating oil passes through the camshaft from the lubrication groove and then passes through the exhaust rocker arm shaft to be pressure-fed to the second injection hole.

3. The variable valve device according to claim 1 or 2, characterized in that: The upper housing is formed with a greater number of the first injection holes than the second injection holes.

4. The variable valve device according to claim 1 or 2, characterized in that: The upper housing is formed with a third injection hole and a fourth injection hole, wherein the third injection hole supplies lubricating oil to the rod end of the intake valve and the fourth injection hole supplies lubricating oil to the rod end of the exhaust valve. The first injection hole and the third injection hole are provided in the same lubricating passage, and the fourth injection hole is provided in the lubricating passage upstream of the second injection hole.

5. The variable valve device according to claim 1 or 2, characterized in that: The first injection hole and the second injection hole are formed to have the same diameter.

6. The variable valve device according to claim 1 or 2, characterized in that: The first spray hole is positioned higher than the second spray hole.

7. The variable valve device according to claim 1, characterized in that: The pair of rocker arm shafts are an intake rocker arm shaft and an exhaust rocker arm shaft, A first lubricating passage and a second lubricating passage are formed in the upper housing. The first lubricating passage is provided with the first spray hole, and the second lubricating passage is provided with the second spray hole. A third lubrication passage connected in series with the first lubrication passage is formed in the intake rocker arm shaft, and a fourth lubrication passage connected in series with the second lubrication passage is formed in the exhaust rocker arm shaft. The first lubrication passage is located above the third lubrication passage, and the second lubrication passage is located above the fourth lubrication passage.

8. The variable valve device according to claim 2, characterized in that: A first lubricating passage and a second lubricating passage are formed in the upper housing. The first lubricating passage is provided with the first spray hole, and the second lubricating passage is provided with the second spray hole. A third lubrication passage connected in series with the first lubrication passage is formed in the intake rocker arm shaft, and a fourth lubrication passage connected in series with the second lubrication passage is formed in the exhaust rocker arm shaft. The first lubrication passage is located above the third lubrication passage, and the second lubrication passage is located above the fourth lubrication passage.

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