JP5994875B2 - Engine valve gear - Google Patents

Description

  The present invention relates to a valve operating apparatus for an engine that includes a camshaft phase varying device that changes a phase of a camshaft in a rotational direction with respect to a crankshaft and that can change valve timings of an intake valve and an exhaust valve.

  Conventionally, this type of engine valve operating apparatus has been disclosed as an engine valve operating apparatus as disclosed in Patent Document 1 previously filed by the same applicant as the present application. As shown in FIG. 12, the camshaft phase varying device 100 in this valve operating device rotates on the intake side camshaft 101 and the driven member 102 that can rotate relative to the intake side camshaft 101 but cannot move in the axial direction. A guide member 103 provided integrally and capable of relative displacement in the rotational direction and the axial direction with respect to the driven member 102, a centrifugal weight 104 disposed between the driven member 102 and the guide member 103, and the driven member 102 and the guide member 103 And an urging member 105 that urges the components in a direction approaching each other.

  The guide member 103 moves relative to the driven member 102 in the rotational direction and the axial direction by moving the centrifugal weight 104 outward in the radial direction against the biasing force of the biasing member 105 due to the centrifugal force. The phase of the intake camshaft 101 relative to the crankshaft is changed relative to the crankshaft. Further, since the camshaft phase varying device 100 needs to be smoothly operated according to the centrifugal force accompanying the engine speed, the guide member 103 which is an important member regarding the operation is coupled to the intake side camshaft 101. A high-precision spline connection is applied. In this spline coupling, the spline groove 106B formed on the inner peripheral surface of the guide member 103 is coupled to the spline key 106A of the intake side camshaft 101 so that the guide member 103 is rotated integrally with the intake side camshaft 101, and It is configured to be movable in the axial direction.

  Furthermore, a variable valve operating apparatus for an internal combustion engine disclosed in Patent Document 2 is disclosed. This valve operating apparatus is a variable valve operating system for an internal combustion engine in which a movable member supported so as to be axially movable on a camshaft changes the operation characteristics of the engine valve by switching the operation and stoppage of the actuator. The camshaft 29 is provided with a guide hole 63 that passes through the shaft and penetrates in the radial direction. A connection pin 65 is inserted through the guide hole 63, and a connection hole 64 provided on the inner surface of the movable member 52. A technique is described in which the movable pin 52 and the camshaft 29 are integrally rotated by engaging the connecting pin 65.

JP 2010-31855 A JP 2010-156239 A

  However, in the invention described in Patent Document 1, the spline key 106A and the spline groove 106B that constitute the spline connection need to be formed with minimal unevenness in order to manufacture with high accuracy. In manufacturing the intake side camshaft 101, the manufacturing cost increases. Further, in the invention described in Patent Document 2, the connecting pin 65 inserted into the guide hole 63 provided in the camshaft 29 is a cylindrical body and is inserted into the connecting hole 64 of the movable member 52 and the end portion is covered with the retainer 73a. Since the fixed member and the movable member 52 and the connecting pin 65 are not provided with a function of separating from each other in the axial direction, the camshaft phase varying device cannot be operated with high accuracy and smoothly.

  The object of the present invention has been made in consideration of the above-described circumstances, and is capable of operating the operating characteristics of the camshaft phase varying device relating to the change of the valve timing with high accuracy and smoothness and operating the engine with good responsiveness. It is to provide a valve device.

  Another object of the present invention is to provide a valve operating device for an engine that can reduce the manufacturing cost by reducing the size of the camshaft phase varying device with a simple configuration.

The present invention relates to a crankshaft, a camshaft that rotates in synchronization with the crankshaft and opens / closes an engine valve, and a camshaft phase variable that relatively changes a phase in the rotational direction of the camshaft with respect to the crankshaft. The camshaft phase varying device transmits the rotation of the crankshaft, is relatively displaceable in the rotational direction with respect to the camshaft, and is not relatively displaceable in the axial direction. A follower member, a guide member provided integrally with the camshaft and rotatable relative to the follower member in a rotational direction and an axial direction; and a guide groove formed on a surface of the follower member facing the guide member And a guide groove formed on a surface of the guide member facing the driven member, A centrifugal weight that transmits rotation to the guide member; and a biasing member that biases the driven member and the guide member toward each other. The camshaft passes through the shaft in a radial direction. An engagement shaft provided with a through-hole penetrating and having a projection having a flat portion at the shaft end is inserted into the through-hole, and the engagement shaft is rotatably provided in the through-hole of the camshaft. The engaging shaft is inserted into the through-hole, and the protruding protrusion is provided in an engaging groove having a flat portion provided facing the inner peripheral surface of the guide member. By engaging the flat surface portion of the engaging groove in surface contact with each other, the guide member is configured to be integrally rotated and slidable with respect to the camshaft, and the centrifugal weight is attached by the action of centrifugal force. It is guided in the guide groove against the biasing force of the biasing member As the guide member moves outward, the guide member moves in a direction away from the driven member along the axial direction of the camshaft, so that the guide member is relatively displaced in the rotational direction and the axial direction with respect to the driven member. The phase in the rotational direction of the camshaft relative to the crankshaft is configured to change relatively.

  According to the present invention, the guide member moves in the direction away from the driven member along the axial direction of the camshaft against the urging force of the urging member due to the centrifugal force. Is relatively displaced in the rotational direction and the axial direction with respect to the driven member, and the phase in the rotational direction of the camshaft relative to the crankshaft is changed relatively. For this reason, the valve timing can be reliably changed with a simple structure, the operation characteristics are stabilized and the reliability is improved with respect to the change of the valve timing, and the responsiveness is also improved.

Further, since the engagement shaft inserted into the through hole of the camshaft is rotatably provided in the through hole of the camshaft, the protrusion provided with the flat portion at the shaft end of the engagement shaft is formed on the inner periphery of the guide member. Since the guide member is configured to engage with the engagement groove having a flat portion provided on the surface, and the cam member is configured to be integrally rotated and slidable on the camshaft, it becomes a simple configuration as compared with the spline structure. The manufacturing cost of the apparatus can be reduced.

1 is a left side view showing a motorcycle equipped with an engine to which an embodiment of an engine valve gear according to the present invention is applied. The longitudinal cross-sectional view which shows the engine of FIG. Sectional drawing which expands the circumference | surroundings of the camshaft phase variable apparatus which is a part of valve operating apparatus of the engine in FIG. 2, and follows the III-III line of FIG. The disassembled perspective view which shows the camshaft phase variable apparatus of FIG. (A) is a front view which shows the driven member of FIG.3 and FIG.4, (B) is the elements on larger scale of the V section of FIG. 5 (A). (A) is a front view which shows the guide member of FIG.3 and FIG.4, (B) is sectional drawing which follows the VI-VI line of FIG. 6 (A), (C) is a schematic diagram of FIG. 6 (B). (A) is sectional drawing which shows the engagement state of the engagement shaft of FIG.3 and FIG.4, (B) is sectional drawing which shows the engagement state in the deformation | transformation form of the engagement shaft of FIG.7 (A). The VIII arrow directional view of FIG. Sectional drawing which follows the IX-IX line | wire of FIG. 3A and 3B are operation explanatory views showing the position of a centrifugal weight at the time of engine low rotation in the camshaft phase varying device of FIG. 3, where FIG. 3A is a cross-sectional view taken along the line III-III of FIG. FIG. 4C is a front view showing the guide member. FIG. 4 is an operation explanatory view showing the position of a centrifugal weight at the time of high engine rotation in the camshaft phase varying device of FIG. 3, (A) is a sectional view taken along line III-III of FIG. 8, and (B) is a front view showing a driven member. FIG. 4C is a front view showing the guide member. Sectional drawing which shows the circumference | surroundings of the camshaft phase variable apparatus in the valve operating apparatus of the conventional engine.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.
FIG. 1 is a left side view showing a motorcycle equipped with an engine to which an embodiment of an engine valve gear according to the present invention is applied. FIG. 2 is a longitudinal sectional view showing the engine of FIG. FIG. 3 is an enlarged cross-sectional view of the periphery of a camshaft phase varying device that is a part of the valve gear of the engine in FIG.

  As shown in FIG. 1, the motorcycle 1 has a body frame 2, and a head pipe 3 is provided in front of the body frame 2. The head pipe 3 is provided with a steering mechanism 7 including a pair of left and right front forks 5, a handle bar 6 and the like, which includes a suspension mechanism (not shown) and rotatably supports the front wheel 4. 4 is steered so as to be pivotable to the left and right.

  On the other hand, the vehicle body frame 2 is, for example, of a twin tube type, and is expanded to the left and right immediately after the head pipe 3 and then serves as a main frame 8 that also serves as a pair of left and right tank rails extending parallel to each other and rearwardly downward. The pair of left and right center frames 9 connected to the rear ends of the main frames 8 and extending substantially upward and downward, and the pair of left and right seat rails 10 extending rearward from the rear upper ends of the center frames 9 are provided. Configured.

  A fuel tank 11 is disposed above the main frame 8, and an operation seat 12 is disposed above the seat rail 10. Further, a pivot shaft 13 is installed at a substantially central lower portion of the center frame 9, and a swing arm 14 is pivotally attached to the pivot shaft 13 so as to be swingable around the pivot shaft 13, and at the rear end of the swing arm 14. The wheel 15 is pivotally supported. An engine 16 is disposed below the fuel tank 11 at the lower center of the vehicle body between the front wheels 4 and the rear wheels 15.

  Further, in the motorcycle 1, the front portion of the vehicle body is covered with a streamlined cowling 17 so as to reduce air resistance during traveling and to protect the rider from traveling wind pressure. Further, a side stand 18 is provided at the lower part of the left center frame 9 in the traveling direction of the vehicle.

  As shown in FIG. 2, the engine 16 is a four-cycle parallel four-cylinder engine, and mainly includes a head cover 19, a cylinder head 20, a cylinder block 21, and an engine case 22. The engine case 22 is of a split type, and has, for example, an upper engine case 22A, a center engine case 22B, and a lower engine case 22C, which are divided into three in the vertical direction in the figure and the cylinder block 21 is integrally formed. Composed.

  The cylinder block 21 is arranged to be inclined slightly forward from the upright, and the bearing portions 24 are respectively divided into upper and lower parts inside the mating surface of the upper engine case 22A and the center engine case 22B. A crankshaft 25 extending in the width direction of the engine 16 is rotatably supported by these bearing portions 24.

  The crankshaft 25 is connected to the large end portion 26 </ b> A of the connecting rod 26, and the piston 27 is connected to the small end portion 26 </ b> B of the connecting rod 26. A piston 27 is accommodated in the cylinder block 21 so as to be slidable substantially in the vertical direction in the figure. A combustion chamber 28 is formed in the space between the cylinder head 20 and the piston 27, and a spark plug 29 is screwed to the center of the combustion chamber 28 from the outside.

  The reciprocating stroke of the piston 27 is converted into a rotational motion by the crankshaft 25, and the drive chain 30 (see FIG. 1) passes through a clutch mechanism and a transmission mechanism (not shown) in the space formed by the center engine case 22B and the lower engine case 22C. Is transmitted to the rear wheel 15 which is a driving wheel.

  The engine 16 also includes a valve operating device 33 that opens and closes an intake valve 31 and an exhaust valve 32 disposed inside the cylinder head 20. This valve operating device 33 is a DOHC (Double Overhead Camshaft) type in the present embodiment.

  This valve operating device 33 is disposed between the aforementioned crankshaft 25 provided with a cam drive sprocket 34 integrally with the rotation, the cylinder head 20 and the head cover 19, and an intake cam 35 is formed integrally with the intake side cam. An exhaust side camshaft 37 provided with a driven sprocket 36 and an exhaust side provided with an exhaust cam 38 integrally formed with an exhaust cam 38 disposed integrally between the cylinder head 20 and the head cover 19. The camshaft 40 is wound around a cam drive sprocket 34, an intake side cam driven sprocket 36, and an exhaust side cam driven sprocket (not shown), and the rotational driving force of the crankshaft 25 is supplied to the intake side cam shaft 37 and the exhaust side cam. These camshafts are transmitted to the shaft 40 And a cam chain 41 for rotating 7 and 40 in synchronization with the crankshaft 25, and a camshaft phase varying device 42 disposed between the intake side camshaft 37 and the intake side cam driven sprocket 36. Is done.

  The intake side camshaft 37 and the exhaust side camshaft 40 extend in the vehicle width direction, and are spaced apart from each other in the vehicle longitudinal direction and arranged in parallel. The intake side camshaft 37 and the exhaust side camshaft 40 are rotatably supported by a bearing portion 39 of the cylinder head 20 and a cam housing 43 attached to the bearing portion 39. The cylinder head 20 and the cylinder block 21 are formed with a cam chain chamber 44 for accommodating the cam chain 41 on the right side in the traveling direction of the vehicle, that is, on the end opposite to the side stand 18.

  Since an exhaust side cam driven sprocket (not shown) around which the cam chain 41 is wound is provided integrally with the exhaust side cam shaft 40, the exhaust cam 38 of the exhaust side cam shaft 40 is driven by the crankshaft 25. Thus, the exhaust valve 32 is driven to open and close by being rotated at the same phase as the crankshaft 25 in the rotational direction.

  The camshaft phase varying device 42 provided between the intake side camshaft 37 and the intake side cam driven sprocket 36 relatively changes the phase of the intake side camshaft 37 relative to the crankshaft 25 in the rotational direction. Is. Accordingly, the intake cam 35 of the intake camshaft 37 is driven by the crankshaft 25 and is driven to rotate in the same or different phase in the rotational direction with respect to the crankshaft 25 to drive the intake valve 31 to open and close. The cam chain 41 is guided by a chain guide (not shown), and its loosening is suppressed by a chain tensioner (not shown).

  The camshaft phase varying device 42 shown in FIG. 3 controls the valve timing of at least one of the intake valve 31 and the exhaust valve 32 (intake valve 31 in the present embodiment) according to the operating state of the engine 16. The valve overlap where the opening timing of the intake valve 31 and the opening timing of the exhaust valve 32 overlap is adjusted. For example, when the engine 16 rotates at a high speed, the valve overlap is set small to prevent the intake air from being blown through, thereby improving the output and fuel consumption, and suppressing the discharge of harmful substances into the exhaust. Further, the valve overlap is set to be large when the engine 16 is running at a low speed, the intake efficiency is increased by utilizing the inertia of the intake air, and the torque of the engine 16 is improved.

  As shown in FIGS. 3 and 4, the camshaft phase varying device 42 includes a driven member 45, a guide member 46, a centrifugal weight 47, a biasing member 48, and a circlip 49. 49, an urging member 48, a guide member 46, a centrifugal weight 47, and a driven member 45 are sequentially arranged from the shaft end side of the intake side camshaft 37.

  As shown in FIGS. 3 and 5, the driven member 45 is formed with the intake side cam driven sprocket 36 as a power receiving portion on the outer peripheral surface, and the rotation of the crankshaft 25 is transmitted via the cam chain 41. The phase in the rotational direction with respect to the crankshaft 25 is fixed (that is, the same). Further, the driven member 45 is provided so as to be relatively displaceable in the rotational direction with respect to the intake side camshaft 37 and not to be relatively displaceable in the axial direction.

Further, as shown in FIGS. 3, 6, and 7 (A), the guide member 46 is configured integrally with the intake side camshaft 37 via an engagement shaft 60. That is, as shown in FIG. 4, the intake side camshaft 37 is formed with a through hole 61 that passes through the axis O and penetrates in the radial direction. Further, the engaging shaft 60 is provided with protrusions 62 having flat portions parallel to the axial direction of the camshaft at both shaft ends. The engaging shaft 60 is inserted into the through hole 61 of the intake side camshaft 37. The In this inserted state, both the protrusions 62 of the engagement shaft 60 protrude from the intake side camshaft 37. Both the protrusions 62 are engaged with engagement grooves 63 each having a flat portion parallel to the axial direction of the pair of camshafts provided to face the inner peripheral surface of the guide member 46.

  Thus, the protrusion 62 having the flat portion of the engaging shaft 60 inserted through the through hole 61 of the intake side camshaft 37 is brought into surface contact engagement with the engaging groove 63 having the flat portion of the guide member 46. Thus, the guide member 46 is provided so as to rotate integrally with the intake side camshaft 37 and to be slidable in the direction of the axis O of the intake side camshaft 37. Further, the guide member 46 is provided so as to be relatively displaceable in the rotational direction and the axial direction with respect to the driven member 45. Note that a two-dot chain line in FIG.

  As shown in FIG. 3, the centrifugal weight 47 is held between guide grooves 51 and 52 (described later) of the driven member 45 and the guide member 46, and transmits the rotation of the driven member 45 to the guide member 46. Further, the biasing member 48 applies a biasing force to bias at least one of the driven member 45 and the guide member 46 (the guide member 46 in the present embodiment) in the direction in which the driven member 45 and the guide member 46 approach each other. give. Further, the circlip 49 is attached to the axial end of the intake camshaft 37 and holds the biasing member 48.

  More specifically, as shown in FIGS. 3 and 5, the driven member 45 has a peripheral wall portion 55 formed on the inner peripheral side of the intake side cam-driven sprocket 36, and the guide member 46 is formed on the inner wall surface 56 of the peripheral wall portion 55. The outer peripheral surface is provided so as to be slidable in the axial direction. The driven member 45 is formed with a plurality of radial guide grooves 51 on a surface facing the guide member 46 at the inner portion of the peripheral wall portion 55. The guide groove 51 guides the centrifugal weight 47, has a constant groove depth, and has an angle θ (FIG. 5B) on one side in the circumferential direction with respect to the radial direction of the driven member 45. Inclined.

  As shown in FIGS. 3 and 6, the guide member 46 has a plurality of radial guide grooves 52 formed on the surface facing the driven member 45. The guide groove 52 guides the centrifugal weight 47 and is formed along the radial direction of the guide member 46. Further, the guide groove 52 is provided with a gradient in which the groove depth becomes shallower toward the radially outward direction of the guide member 46, and the gradient becomes steeper as the radial direction outward of the guide member 46. Configured as follows. That is, the gradient of the groove depth of the guide groove 52 is set to the gradient α on the radially inner side of the guide member 46 and the gradient β (β> α) on the outer side. The gradient α and the gradient β are configured to change smoothly near a certain point (point X in FIG. 6B) at the bottom of the guide groove 52. Due to the gradients α and β of the guide groove 52, the guide groove 51 of the driven member 45 and the guide groove 52 of the guide member 46 are configured such that the groove bottoms approach each other as they go radially outward.

  Specifically, in the guide groove 52 of the guide member 46, the radially inner plane of the gradient α smoothly continues to the radially outer plane of the gradient β via a curved surface having a required curvature P. As shown in FIG. 6C, a curved surface passing through a certain point X has a curved surface shape formed with a required curvature P, and both sides (radially inner side and radially outer side) of the curved surface have a gradient α and a gradient. It is configured in a planar shape of β.

  The centrifugal weight 47 shown in FIG. 3 is made of a material having a large specific gravity, such as steel or tungsten, and is formed in a ball shape. The urging member 48 is a disc spring in the present embodiment, but may be a corrugated spring, a spiral spring (bamboo spring), or the like. Further, as shown in FIGS. 3 and 8, the circlip 49 is coupled to the shaft end of the intake camshaft 37, supports the seat surface 58 of the urging member 48, and is attached to the guide member 46. The biasing member 48 is held. Thereby, the urging force of the urging member 48 is applied to the guide member 46.

  As shown in FIGS. 3 and 9, the intake side camshaft 37 is formed with an oil passage 65 in the center portion passing through the axis O along the direction of the axis O, and communicated with the oil passage 65. Thus, the introduction passage 66 and the branch passage 67 are formed orthogonal to the axis O of the intake camshaft 37. The introduction passage 66 has an inner end that opens to the oil passage 65 and an outer end that opens to an oil groove 68 formed in a ring shape in the bearing 39 for the intake camshaft 37 and the cam housing 43. The branch passage 67 has an inner end that opens to the oil passage 65 and an outer end that opens to a sliding surface with the guide member 46 on the outer peripheral surface of the intake camshaft 37.

  The engine oil introduced into the oil groove 68 of the bearing portion 39 and the cam housing 43 flows into the oil passage 65 from the oil groove 68 through the introduction passage 66 as shown by an arrow M, and as shown by an arrow N. The oil is supplied from the oil passage 65 through the branch passage 67 to the camshaft phase varying device 42 (particularly, the sliding surface between the guide member 46 and the intake side camshaft 37 and the centrifugal weight 47 in the guide grooves 51 and 52). The camshaft phase varying device 42 is lubricated. Thereafter, the engine oil is discharged out of the camshaft phase varying device 42 through an oil discharge hole 69 formed in the guide groove 51 of the driven member 45 shown in FIGS. 3 and 5A.

  The oil discharge holes 69 are radially inward of several (e.g., three) guide grooves 51 located at substantially equal intervals in the circumferential direction of the driven member 45 among the plurality of guide grooves 51 formed in the driven member 45. It is formed through the position. Further, as shown in FIG. 9, the oil passage 65 formed in the central portion passing through the axis O of the intake side camshaft 37 is closer to the axial end side of the intake side camshaft 37 than the branch passage 67. The shaft 37 passes through the axis O and is closed by the engagement shaft 60 disposed in the radial direction. Therefore, the oil passage 65 does not require a dedicated oil plug on the shaft end side of the intake side camshaft 37.

  In the camshaft phase varying device 42 configured as described above, centrifugal force acts on the centrifugal weight 47, and the centrifugal weight 47 moves radially outside the guide grooves 51 and 52 of the driven member 45 and the guide member 46, respectively. Move towards. Accordingly, the guide member 46 moves in the direction away from the driven member 45 along the axial direction of the intake side camshaft 37 against the urging force of the urging member 48, and the guide groove 51 of the driven member 45. The relative displacement in the rotational direction with respect to the driven member 45 is caused by the action of the inclination (angle θ). As a result, the phase of the rotation direction of the intake camshaft 37 relative to the crankshaft 25 changes relatively, and the valve timing of the intake valve 31 by the intake cam 35 of the intake camshaft 37 is changed.

Next, the operation will be described.
As shown in FIG. 10, when the engine 16 is in the low rotation range, the centrifugal force acting on the centrifugal weight 47 is small, and this centrifugal weight 47 is applied to the gradient α of the guide groove 52 of the guide member 46 and the biasing member 48. The action of the force remains at the initial position of the radially inner ends of the guide grooves 51 and 52. For this reason, the intake side camshaft 37 has the same rotational phase as the intake side cam driven sprocket 36, that is, the crankshaft 25, and the intake cam 35 formed integrally with the intake side camshaft 37 has a phase when assembled. Then, the intake valve 31 is driven. As a result, the intake valve 31 and the exhaust valve 32 become valve timings for low and medium speeds with large valve overlap, and the medium speed torque is improved.

  As shown in FIG. 11, when the engine 16 reaches a high rotation range, the centrifugal force acting on the centrifugal weight 47 increases, and the centrifugal weight 47 is in the guide groove 51 of the driven member 45 and the guide groove 52 of the guide member 46. Is moved radially outward. As a result, the guide member 46 moves outward (in the direction of arrow A) in the axial direction of the intake side camshaft 37 against the urging force of the urging member 48 by the action of the gradients α and β of the guide groove 52. To do. At this time, the guide groove 51 of the driven member 45 is provided with an inclination of an angle θ (FIG. 5) on one side in the circumferential direction with respect to the radial direction. 11 (B) and (C) in the direction of arrow B) relative to the driven member 45 by the angle θ. The direction opposite to the arrow B direction in FIGS. 11B and 11C is the rotation direction R of the intake camshaft 37.

  As a result, the intake camshaft 37 rotates relative to the crankshaft 25 by the surface contact coupling action of the engaging shaft 60 having a flat portion with the guide member 46 and the engaging groove 63 having the flat portion. The phase of changes. The change in the phase of the intake side camshaft 37 at this time is in the direction opposite to the rotation direction R of the intake side camshaft 37 (retard side). Accordingly, the intake cam 35 formed integrally with the intake side camshaft 37 drives the intake valve 31 with a phase that has changed to the retard side from the phase at the time of assembly. As a result, the intake valve 31 and the exhaust valve 32 provide high-speed valve timing with a small valve overlap, improving the output and fuel consumption of the engine 16 and suppressing the discharge of harmful substances.

  When the rotational speed of the engine 16 is reduced, the centrifugal force acting on the centrifugal weight 47 is reduced. Therefore, the urging force by the urging member 48 is superior to the force that moves the guide member 46 in the direction of arrow A by the centrifugal force. The guide member 46 moves to the driven member 45 side by the action of the urging force of the urging member 48, the centrifugal weight 47 moves to the inside in the radial direction of the guide grooves 51 and 52, and the guide member 46 and the centrifugal weight 47 eventually become. The original position shown in FIG. 10 is restored. As the centrifugal weight 47 returns to the original position, the guide member 46 rotates relative to the driven member 45 in the advance side (the direction opposite to the arrow B direction in FIGS. 11B and 11C). The intake side camshaft 37 changes the phase toward the advance side with respect to the crankshaft 25 by the action of the combined shaft 60 and the engaging groove 63. As a result, the intake valve 31 and the exhaust valve 32 have a valve timing for low and medium speeds with a large valve overlap, and the medium speed torque is improved as described above.

With the configuration as described above, the following effects (1) to (8) are achieved according to the present embodiment.
(1) As shown in FIG. 3, in the camshaft phase varying device 42, the centrifugal weight 47 moves against the urging force of the urging member 48 by the action of centrifugal force, so that the guide member 46 is driven by the driven member 45. To the rotation direction, the phase of the rotation direction of the intake camshaft 37 relative to the crankshaft 25 is changed relatively. For this reason, the valve timing of the intake valve 31 can be reliably changed with a simple structure, and the operation characteristics are stabilized and reliability is improved with respect to the change of the valve timing, and the responsiveness is also improved.

  (2) By rotating the guide member 46 relative to the driven member 45, the phase in the rotational direction of the intake camshaft 37 relative to the crankshaft 25 is relatively changed. Since the structure is not slid in the direction, the valve gear 33 including the periphery of the cylinder head 20 and thus the engine 16 can be reduced in size.

  (3) The protrusion 62 provided with the flat portions at both shaft ends of the engagement shaft 60 inserted through the through hole 61 of the intake side camshaft 37 has a flat portion formed on the inner peripheral surface of the guide member 46. The guide member 46 is configured to rotate integrally with the intake side camshaft 37 by engaging with the engaging groove 63. For this reason, compared with the case where the intake side camshaft 37 and the guide member 46 are spline-coupled, the coupling between the intake side camshaft 37 and the guide member 46 becomes a simple configuration, so that the camshaft phase varying device 42 ( As a result, the manufacturing cost of the valve gear 33) can be reduced.

  (4) Since the engagement shaft 60 is rotatable in the through hole 61 of the intake side camshaft 37, as shown in FIGS. 3 and 4, the protrusions having flat portions at both shaft ends of the engagement shaft 60 62 and the engaging groove 63 provided with the flat portion of the guide member 46 can always be brought into surface contact with each other, and the contact surface pressure between the protrusion 62 and the engaging groove 63 can be stabilized. Further, since the engagement shaft 60 is formed of a member different from the intake side camshaft 37, the engagement shaft 60 can be formed of a material having excellent wear resistance. As a result, the wear resistance and slidability of the joint portion between the intake camshaft 37 and the guide member 46 can be improved.

(5) The engagement shaft 60 passes through the axis O of the intake side camshaft 37 and engages the protrusions 62 provided at both shaft ends of the engagement shaft 60 with the engagement groove 63 of the guide member 46. Therefore, as shown in FIG. 7A, both protrusions 62 of the engagement shaft 60 are formed on the axis O of the intake camshaft 37 by the same angle in the rotation direction R as the intake camshaft 37 rotates. Tilt symmetrically. As a result, both the protrusions 62 of the engagement shaft 60 transmit the same stress to the guide member 46 simultaneously with respect to the engagement groove 63 of the guide member 46, so that the camshaft phase varying device 42 is highly accurate. And can be operated smoothly.

  (6) Like the conventional camshaft phase varying device 100 shown in FIG. 12, the guide member 103 and the intake camshaft 101 are spline-coupled by the spline key 106A and the spline groove 106B, and the shaft end of the oil passage 108 is connected to the shaft end. Compared with a structure closed by a bolt 107 that functions as an oil plug, the present embodiment has the following advantages. That is, as shown in FIG. 3, the guide shaft 46 and the intake side camshaft 37 are coupled using the engagement shaft 60 and the oil passage 65 is closed, so that the oil for closing the oil passage 65 is closed. No plug is required, and the camshaft phase varying device 42 and the valve operating device 33 having a simple structure can be realized.

  (7) In the conventional camshaft phasing apparatus 100, the oil passage 108 is closed by screwing a bolt 107 functioning as an oil plug at the shaft end of the intake side camshaft 101. Therefore, it is necessary to set the axial length of the bolt 107 to be long and screw it to the intake camshaft 101 in order to prevent the sealing performance from being lowered. For this reason, the branch passage 109 that communicates with the oil passage 108 and guides the engine oil to the camshaft phase varying device 100 can only be provided on the radially outer side of the bolt 107, and the engine oil supplied to the camshaft phase varying device 100 There is a risk that the amount will be insufficient.

  On the other hand, in the camshaft phase varying device 42 of this embodiment, as shown in FIG. 3, the engagement shaft 60 is inserted in the radial direction of the intake side camshaft 37 and provided on the intake side camshaft 37. Since the oil passage 65 is closed, a sufficient space for forming the oil passage 65 in the central portion of the axis O of the intake side camshaft 37 can be secured. Therefore, a sufficient amount of engine oil can be supplied to the camshaft phase varying device 42 by forming the oil passage 65 in this space.

(8) The engine oil introduced into the camshaft phase varying device 42 from the oil passage 65 of the intake side camshaft 37 through the branch passage 67 (FIGS. 3 and 9) is driven by the driven member 45 of the camshaft phase varying device 42. The oil is discharged to the outside through an oil discharge hole 69 formed through the guide groove 51. Since the oil discharge hole 69 is formed on the inner diameter side of the guide groove 51, the engine oil introduced via the branch passage 67 between the guide groove 51 of the driven member 45 and the guide groove 52 of the guide member 46 is centrifuged. The oil can be discharged before the oil pressure acts on the weight 47. As a result, it is possible to prevent a change in the operating characteristics of the camshaft phase varying device 42 caused by the oil pressure of the engine oil introduced between the guide grooves 51 and 52 via the branch passage 67 acting on the centrifugal weight 47. Moreover, the engine oil can satisfactorily lubricate the centrifugal weight 47 regardless of the position between the guide grooves 51 and 52.

  As mentioned above, although this invention was demonstrated based on the said embodiment, this invention is not limited to this, A various deformation | transformation can be made in the range which does not deviate from the main point of this invention. For example, a camshaft phase varying device similar to the camshaft phase varying device 42 is installed on the exhaust side camshaft 40 so that the rotational direction phase of the exhaust side camshaft 40 is advanced with respect to the crankshaft 25 at the time of high engine rotation. The valve timing of the intake valve 31 and the exhaust valve 32 may be changed to a high-speed valve timing with a small valve overlap.

  In addition, camshaft phase variable devices are installed on both the intake side camshaft 37 and the exhaust side camshaft 40 so that the valve timings of the intake valve 31 and the exhaust valve 32 can be adjusted at high speed with small valve overlap at the time of high engine speed. You may comprise so that it may change to the valve timing for use.

  Further, as shown in FIG. 7 (B), when the transmission power transmitted from the guide member 46 of the camshaft phase varying device 42 to the intake side camshaft 37 is small, it projects only at one end of the engagement shaft 60. 62 may be provided.

16 Engine 25 Crankshaft 31 Intake valve 32 Exhaust valve 33 Valve operating device 35 Intake cam 37 Intake side camshaft 42 Camshaft phase varying device 45 Follower member 46 Guide member 47 Centrifugal weight 48 Energizing member 51, 52 Guide groove 60 Engagement Shaft 61 Through hole 62 Protrusion 63 Engaging groove 65 Oil passage 67 Tributary passage O Shaft

Claims (1)

A crankshaft,
A camshaft that rotates in synchronization with the crankshaft and opens and closes the valve of the engine;
A valve operating device for an engine having a camshaft phase varying device that relatively changes a phase in a rotational direction of the camshaft with respect to the crankshaft;
The camshaft phase varying device is
A driven member to which the rotation of the crankshaft is transmitted and which is relatively displaceable in the rotational direction with respect to the camshaft and is not relatively displaceable in the axial direction;
A guide member provided integrally with the camshaft and capable of relative displacement in the rotational direction and the axial direction with respect to the driven member;
The guide member is held between a guide groove formed on a surface of the driven member facing the guide member and a guide groove formed on a surface of the guide member facing the driven member, and the rotation of the driven member is guided by the guide. A centrifugal weight to be transmitted to the member;
An urging member that urges the driven member and the guide member toward each other;
The camshaft is provided with a through-hole that passes through the shaft in the radial direction, and an engagement shaft having a projection having a flat portion at the shaft end is inserted through the through-hole, and the engagement The shaft is rotatably provided in the through hole of the camshaft, the engagement shaft is inserted into the through hole, and the protruding protrusion is provided to face the inner peripheral surface of the guide member. The guide member rotates and is slidable with respect to the camshaft by engaging the flat portion of the protrusion and the flat portion of the engagement groove in surface contact with the engaging groove having a flat portion. Composed of
As the centrifugal weight is guided by the guide groove against the urging force of the urging member under the action of centrifugal force and moves radially outward, the guide member also follows the axial direction of the camshaft. And moving in a direction away from the driven member so that the driven member is displaced relative to the driven member in the rotational direction and the axial direction, and the phase in the rotational direction of the camshaft relative to the crankshaft is changed relatively. A configured valve gear for an engine.

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