JP5712025B2 - Rocker arm support structure in valve gear mechanism for engine - Google Patents

Description

  In the present invention, a camshaft is rotatably supported on a pair of shaft support portions formed on a camshaft holder provided in a cylinder head, and a rocker shaft having an axis parallel to the camshaft is supported. A rocker arm having an arm main portion disposed between shaft support portions and supported by the rocker shaft so as to be swingable is interposed between the engine valve disposed on the cylinder head so as to be opened and closed and the cam shaft. The present invention relates to an engine valve mechanism.

  A rocker arm having a main part of an arm that is supported between a pair of shaft support portions formed on a camshaft holder provided in a cylinder head and is supported between the shaft support portions and swingable on the rocker shaft. However, an engine valve mechanism that is interposed between the engine valve and the camshaft is already known from Patent Document 1 and the like.

JP 2004-116297 A

  Since the structure disclosed in Patent Document 1 has a structure in which the main part of the rocker arm is in direct surface contact with the shaft support part, friction due to rocking of the rocker arm occurs. In order to reduce this friction, it is conceivable that a washer is interposed between both end faces of the arm main part and the shaft support part. However, between the pair of shaft support parts formed on the camshaft holder provided in the cylinder head. With the structure in which the rocker shaft is assembled so as to be inserted into both the shaft support portion and the arm main portion in a state where the arm main portion is disposed, it is difficult to position and hold the washer.

  The present invention has been made in view of such circumstances, and in order to reduce the friction by interposing a washer between the shaft support portion and the arm main portion, the washer can be easily positioned and held for simple assembly. An object of the present invention is to provide a rocker arm support structure in an engine valve mechanism.

In order to achieve the above object, according to the present invention, a camshaft is rotatably supported on a pair of shaft support portions formed on a camshaft holder provided in a cylinder head and has an axis parallel to the camshaft. An engine valve in which a rocker arm is supported, and a rocker arm having an arm main part which is disposed between the shaft support parts and is supported by the rocker shaft so as to be swingable is disposed on the cylinder head so as to be opened and closed. And a valve operating mechanism for an engine interposed between the camshafts, a washer that allows the rocker shaft to pass between both ends of the arm main portion and the shaft support portions along the axial direction of the rocker shaft. These washers are interposed between the arm main part and the shaft support parts. A ring plate portion, is formed an annular protruding portion which protrudes from the inner periphery of the ring plate portion is press-fitted to the arm main part so that each integrally having an annular projection of the two washers of the rocker shaft The first feature is that each of them is inserted between the outer periphery and the inner periphery of the main arm portion, and is spaced apart from each other in the axial direction so that an annular space is formed between the annular protrusions. To do.

According to the present invention, in addition to the configuration of the first feature, the inner diameter of the annular projecting portion that forms a through-hole through which the rocker shaft is penetrated is such that the inner peripheral surface of the annular projecting portion is the outer peripheral surface of the rocker shaft. to be set so as to sliding contact shall be the second feature.

The present invention, in addition to the first or second feature, the washer is a third feature in that it consists of a resin.

In the present invention, a camshaft is rotatably supported on a pair of shaft support portions formed on a camshaft holder provided in a cylinder head, and a rocker shaft having an axis parallel to the camshaft is supported. A rocker arm having an arm main portion disposed between shaft support portions and supported by the rocker shaft so as to be swingable is interposed between the engine valve disposed on the cylinder head so as to be opened and closed and the cam shaft. In the engine valve mechanism, a washer for interposing the rocker shaft between the arm main portion and the shaft support portion is interposed, and a needle bearing is interposed between the arm main portion and the rocker shaft. , and the washer retainer is a separate part, the axis of the rocker shaft Washer holding portion for holding the inserted and the washer to the inner periphery of the washer with protruding from both ends of the arm main portion along the direction to the fourth being formed integrally.

Furthermore, in addition to the configuration of the fourth feature of the present invention, the projection length of the washer holding portion from both ends of the arm main portion along the axial direction of the rocker shaft is such that the length of the washer holding portion extends along the axis of the rocker shaft. The fifth feature is that the thickness of the washer is set smaller than the thickness of the washer.

  The intake valve 43 and the exhaust valve 44 of the embodiment correspond to the engine valve of the present invention, the intake side rocker arm 49 and the exhaust side rocker arm 50 of the embodiment correspond to the rocker arm of the present invention, and the intake side of the embodiment. The rocker shaft 55 and the exhaust side rocker shaft 56 correspond to the rocker shaft of the present invention.

According to the first aspect of the present invention, the rings in which the washers respectively interposed between both ends of the arm main portion along the axial direction of the rocker shaft and between the shaft support portions are interposed between the arm main portion and the shaft support portion. Since the plate portion and the annular protrusion portion that protrudes from the inner periphery of the ring plate portion and protrudes between the rocker shaft and the arm main portion are integrally provided, it is possible to reduce friction at the ring plate portion, and When assembling the shaft so as to be inserted into both shaft support portions and the arm main portion, the washer can be easily positioned and held by inserting the annular protrusion into the rocker shaft, so that simple assembly can be performed. . In this case, the assembly can be made easier by fixing the washer to the rocker arm so as to press-fit the annular projecting portion into the arm main portion.

  According to the second feature of the present invention, since the inner peripheral surface of the annular projecting portion is in sliding contact with the outer peripheral surface of the rocker shaft, the washer can receive a radial load from the rocker arm.

According to the third feature of the present invention, the washer is made of resin, so that friction can be further reduced, cost can be reduced, and assembly can be facilitated.

According to the fourth feature of the present invention, a washer holding portion that protrudes from both ends of the arm main portion along the axial direction of the rocker shaft is formed integrally with the retainer that is a separate component from the washer of the needle bearing. Since the washer holding part is inserted into the inner periphery of the washer to hold the washer , the washer can be easily positioned and held when assembling so that the rocker shaft is inserted into both the shaft support part and the arm main part . Easy assembly is possible.

Furthermore, according to the fifth feature of the present invention, since the length of the washer holding portion projecting from both ends of the arm main portion along the axial direction of the rocker shaft is smaller than the thickness of the washer, the washer holding portion, the shaft support portion, Thus, the thrust load from the rocker arm can be reliably received by the washer.

1 is a side view of a motorcycle according to a first embodiment. It is a longitudinal cross-sectional view of the engine main body which follows the 2-2 line of FIG. FIG. 3 is a sectional view taken along line 3-3 in FIG. 2. FIG. 4 is a view taken along line 4-4 in FIG. 2. FIG. 5 is an enlarged sectional view taken along line 5-5 of FIG. It is sectional drawing corresponding to FIG. 5 of 2nd Embodiment.

  Embodiments of the present invention will be described with reference to the accompanying drawings.

  A first embodiment of the present invention will be described with reference to FIGS. 1 to 5. First, in FIG. 1, a head pipe 11 provided at a front end of a body frame F of a motorcycle has a front that pivotally supports a front wheel WF. A fork 12 is supported so that it can be steered, and the front end of a swing arm 14 that pivotally supports a rear wheel WR at the rear end is provided via a support shaft 15 on a pivot plate 13 that the vehicle body frame F has in the middle in the front-rear direction. A rear cushion unit 16 is provided between the swing arm 14 and the vehicle body frame F.

  The rear wheel WR is rotationally driven by the power exhibited by the engine E that is a spark ignition four-cycle. The engine body 17 of the engine E is configured as an air-cooled single cylinder, and the vehicle body frame F It is mounted on the vehicle body frame F while being arranged below the fuel tank 18 mounted on the vehicle body. A riding seat 19 located behind the fuel tank 18 is supported on the rear portion of the vehicle body frame F.

  2 and 3, the engine body 17 slides on a crankcase 22 that rotatably supports a crankshaft 21 having an axis extending in the vehicle width direction of a motorcycle, and a piston 26 that is connected to the crankshaft 21. A cylinder block 23 having a cylinder bore 27 to be movably fitted and coupled to the crankcase 22, a cylinder head 24 coupled to the cylinder block 23, and a valve operating chamber 28 between the cylinder head 24. And a head cover 25 coupled to the cylinder head 24, and mounted on the vehicle body frame F in a posture in which the axis of the cylinder bore 27, that is, the cylinder axis C is inclined upward.

  In addition, a plurality of cooling fins 29, 29,..., 30, 30... Are provided on the outer surfaces of the cylinder block 23 and the cylinder head 24 at intervals in the direction along the cylinder axis C.

  A combustion chamber 31 that faces the top of the piston 26 is formed between the cylinder head 24 and the cylinder block 23. The cylinder head 24 having a dome surface 32 facing the combustion chamber 31 includes the dome. One intake valve port 33 and one exhaust valve port 34 that are open on the surface 32 are provided, and an intake port 35 that opens to the rear side surface of the cylinder head 24 connected to the intake valve port 33, and the exhaust valve port 34. And an exhaust port 36 that opens on the front side surface of the cylinder head 24 is provided. An intake device 37 (see FIG. 1) is connected to the intake port 35, and the exhaust port 36 is shown in FIG. Thus, an exhaust device 39 including an exhaust muffler 38 disposed on the right side of the rear wheel WR is connected.

  In addition, the first and second spark plugs 41 and 42 are attached to the cylinder head 24 so that the front ends thereof face the combustion chamber 31, and the intake valve port 33 and the exhaust valve port 34 are connected to the cylinder head 24. An intake valve 43 and an exhaust valve 44 as engine valves that can be respectively closed are disposed so as to be able to open and close. Be energized by.

  Referring also to FIG. 4, a valve operating mechanism 47 that opens and closes the intake valve 43 and the exhaust valve 44 is accommodated in the valve operating chamber 28 between the cylinder head 24 and the head cover 25.

  The valve operating mechanism 47 includes a single camshaft 48 that is disposed between the intake valve 43 and the exhaust valve 44 in common with the intake valve 43 and the exhaust valve 44, and is interposed between the intake valve 43 and the camshaft 48. An intake side rocker arm 49 provided, and an exhaust side rocker arm 50 interposed between the exhaust valve 44 and the camshaft 48 are provided.

  A pair of shaft support portions 51 a disposed on the camshaft holder 51 provided in the cylinder head 24 at positions spaced in a direction along the axis of the camshaft 48 having an axis parallel to the crankshaft 21. 51b is formed, and the camshaft 48 is rotatably supported by the shaft support portions 51a and 51b via ball bearings 53 and 54, respectively.

  The shaft support portions 51 a and 51 b are fitted and supported at both ends of an intake side rocker shaft 55 and an exhaust side rocker shaft 56 which have an axis parallel to the camshaft 48 and are arranged on both sides of the camshaft 48. The intake-side rocker arm 49 is swingably supported by the intake-side rocker shaft 55, and the exhaust-side rocker arm 50 is swingably supported by the exhaust-side rocker shaft 56.

  In FIG. 5, the intake-side rocker arm 49 is disposed between the shaft support portions 51a and 51b, and is supported by the intake-side rocker shaft 55 so as to be swingable, and from the arm main portion 49a. The first arm portion 49b extending to the camshaft 48 side and the second arm portion 49c extending from the arm main portion 49a to the intake valve 43 side are integrally formed, and both ends of the arm main portion 49a and the Washers 81, 81 that allow the intake-side rocker shaft 55 to pass therethrough are interposed between the shaft support portions 51a, 51b.

  The washer 81 is made of resin, and protrudes from the inner periphery of the ring plate portion 81a and the ring plate portion 81a interposed between the arm main portion 49a and the shaft support portions 51a and 51b. The rocker shaft 55 and an annular projecting portion 81b that projects between the arm main portion 49a are integrally provided.

Moreover, the inner diameter of the annular projecting portion 81b that forms the through hole 82 that allows the intake side rocker shaft 55 to pass therethrough is such that the inner peripheral surface of the annular projecting portion 81b slides on the outer peripheral surface of the intake side rocker shaft 55. The annular projecting portion 81b is press-fitted into the arm main portion 49a. The annular protrusions 81b and 81b of both washers 81 and 81 are spaced apart from each other in the axial direction of the intake-side rocker shaft 55, and the intake-side rocker shaft 55 is interposed between the annular protrusions 81b and 81b. An annular space S is formed to surround.

  A roller 59 that is in rolling contact with the intake side cam 57 provided on the camshaft 48 is pivotally supported at the distal end portion of the first arm portion 49b of the intake side rocker arm 49, and the distal end portion of the second arm portion 49c is A tappet screw 61 abutting on the stem end 43a of the intake valve 43 is screwed so that the advance / retreat position can be adjusted.

  The exhaust-side rocker arm 50 is disposed between the shaft support portions 51a and 51b, and is supported by the exhaust-side rocker shaft 56 so as to be swingable. The first arm portion 50b extending to the 48 side and the second arm portion 50c extending from the arm main portion 50a to the exhaust valve 44 side are integrally provided, and both ends of the arm main portion 50a and the shaft support are provided. Washers 81 and 81 that allow the exhaust rocker shaft 55 to pass therethrough are interposed between the portions 51a and 51b, respectively.

  Thus, the exhaust side rocker arm 50 and the washers 81 disposed between the shaft support portions 51a and 51b are also disposed between the intake side rocker arm 49 and the shaft support portions 51a and 51b, respectively. It is formed in the same manner as the washer 81.

  A roller 60 that is in rolling contact with an exhaust side cam 58 provided on the camshaft 48 is pivotally supported at the distal end portion of the first arm portion 50b of the exhaust side rocker arm 50, and the distal end portion of the second arm portion 50c is A tappet screw 62 that abuts on the stem end 44a of the exhaust valve 44 is screwed so that the advance / retreat position can be adjusted.

  The rotational power of the crankshaft 21 is transmitted to the camshaft 48 while being reduced by half by the timing transmission mechanism 64, and the timing transmission mechanism 64 is connected to the shaft of the camshaft holder 51. An endless cam chain 67 is wound around a driven sprocket 65 fixed to the end of the camshaft 48 protruding from the support portion 51b and a drive sprocket 66 fixed to the crankshaft 21.

  In order to run the cam chain 67, a cam chain chamber 68 is formed in the crankcase 22, the cylinder block 23 and the cylinder head 24 of the engine body 17.

  Incidentally, the first spark plug 41 is screwed into a first plug mounting hole 69 provided in the cylinder head 24 so as to be disposed on the opposite side of the cam chain chamber 68 with respect to the cylinder axis C. The second spark plug 42 is screwed into a second plug mounting hole 70 provided in the cylinder head 24 on the side opposite to the first plug mounting hole 69 with respect to the cylinder axis C. 42 is disposed in the cylinder head 24 so as to pass through the loop of the cam chain 67.

  The cylinder head 24 has an opening 71 for attaching the cam shaft 48 rotatably supported by both shaft support portions 51a and 51b of the cam shaft holder 51 to the cylinder head 24. 68. A side cover 72 that closes the opening 71 is attached to the cylinder head 24 with a plurality of bolts 73, 73. Moreover, cooling fins 74, 74... Are also provided on the outer surface of the side cover 72.

  Thus, the second spark plug 42 is inserted into the cylinder member 75 whose both ends are supported by the cylinder head 24 and the side cover 72 attached to the cylinder head 24 from the outside. Both ends of the cylindrical member 75 are fitted and supported on the cylinder head 24 and the side cover 72 via annular seal members 76 and 77.

  The cylinder head 24 is provided with a fitting hole 78 into which one end of the cylindrical member 75 is fitted, and is provided coaxially with the second plug mounting hole 70 into which the second spark plug 42 is screwed. An annular seal member 76 attached to the outer periphery of one end of the member 75 elastically contacts the inner periphery of the fitting hole 78.

  The other end of the cylindrical member 75 is provided with a flange portion 75a that projects outward in the radial direction, and an annular seal member 77 that is attached to the cylindrical member 75 on the other end side of the flange portion 75a. The side cover 72 is provided with a support hole 79 having a stepped portion 79a sandwiched between the flanged portion 75a and having a stepped portion at the intermediate portion.

  Next, the operation of the first embodiment will be described. The intake side rocker shaft 55 and the exhaust side rocker shaft 56 are provided on a pair of shaft support portions 51a and 51b formed on the camshaft holder 51 provided on the cylinder head 24. An intake-side and exhaust-side rocker arm 49 having arm main portions 49a, 50a that are supported and disposed between the shaft support portions 51a, 51b and supported by the intake-side and exhaust-side rocker shafts 55, 56 in a swingable manner. , 50 are interposed between the intake valve 43 and the exhaust valve 44 and the camshaft 48, both ends of the arm main portions 49a, 50a along the axial direction of the rocker shaft 48 and the shaft support portions 51a, 51b. A washer 81 for allowing the intake and exhaust rocker shafts 55 and 56 to pass therethrough. Each of the washers 81 is interposed between a ring plate portion 81a interposed between the arm main portions 49a and 50a and the shaft support portions 51a and 51b, and an inner periphery of the ring plate portion 81a. Projecting from the intake-side and exhaust-side rocker shafts 55, 56 and the annular projecting portions 81b, which are inserted between the arm main portions 49a, 50a, respectively. In the case where the intake side and exhaust side rocker shafts 55 and 56 are inserted into both shaft support parts 51a and 51b and the arm main parts 49a and 50a, the annular projecting part 81b can be reduced. Are easily positioned by inserting them into the intake and exhaust rocker shafts 55, 56. It can be lifting, so that it is easy assembly.

  Further, the inner diameter of the annular projections 81b forming the through-holes 82 through which the intake side and exhaust side rocker shafts 55, 56 are passed, and the inner peripheral surfaces of the annular projections 81b are used as the intake side and exhaust side rocker. Since it is set so as to be in sliding contact with the outer peripheral surfaces of the shafts 55 and 56, the washer 81 can receive radial loads from the intake side and exhaust side rocker arms 49 and 50.

  Further, since the annular projecting portions 81b are press-fitted into the arm main portions 49a and 50a, the washer 81 is fixed to the intake side and the exhaust side rocker arms 49 and 50 so that the assembly can be made easier. can do.

  Further, since the washer 81 is made of a resin, it is possible to reduce the friction, reduce the cost, and facilitate the assembly.

  A second embodiment of the present invention will be described with reference to FIG. 6, but the parts corresponding to the first embodiment are only given the same reference numerals, and the detailed description will be given. Omitted.

A needle bearing 84 is interposed between the arm main portion 49 a of the intake side rocker arm 49 and the intake side rocker shaft 55 , and the retainer 85, which is a separate component from the washer 86, provided in the needle bearing 84, Washer holding portions 85a and 85a projecting from both ends of the arm main portion 49a along the axial direction of the intake side rocker shaft 55 are integrally formed.

  On the other hand, annular washers 86 and 86 that allow the intake-side rocker shaft 55 to pass through are interposed between the arm main portion 49a and the pair of shaft support portions 51a and 51b, respectively. 85a ... are inserted into the washer 86 ... to hold the washer 86 ....

  In addition, the washer 86 in the direction along the axis of the intake side rocker shaft 55 is such that the protruding length L of the washer holding portion 85a from both ends of the arm main portion 49a along the axial direction of the intake side rocker shaft 55 Is set smaller than the thickness D.

  The exhaust rocker arm 50 (see the first embodiment) is also supported on the exhaust rocker shaft 56 (see the first embodiment) with the same support structure as the intake rocker arm 49.

According to the second embodiment, the retainer 85 of the needle bearing 84 is provided with a washer holding portion 85a protruding from both ends of the arm main portions 49a, 50a along the axial direction of the intake side rocker shaft 55 and the exhaust side rocker shaft 56. Are integrally formed, and the washer holding portion 85a is inserted into the inner periphery of the washer 86 to hold the washer 86. Therefore, the washer 86 can be easily positioned and held, and simple assembly is possible. become able to.

  Further, the protruding length L of the washer holding portions 85a from both ends of the arm main portions 49a, 50a along the axial direction of the intake side rocker shaft 55 and the exhaust side rocker shaft 56 is determined by the intake side rocker shaft 55 and The washer 86 in the direction along the axis of the exhaust side rocker shaft 56 is set to be smaller than the thickness D. Therefore, interference between the washer holding portion 85a and the shaft support portions 51a and 51b is avoided, and the washer 86. Thus, the thrust load from the intake side and exhaust side rocker arms 49 and 50 can be reliably received.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the present invention described in the claims. Is possible.

24 ... Cylinder head 43 ... Intake valve 44 as engine valve ... Exhaust valve 47 as engine valve ... Valve mechanism 48 ... Camshaft 49 ... Intake side rocker arm 49a as rocker arm , 50a ... arm main part 50 ... exhaust side rocker arm 51 as a rocker arm ... camshaft holders 51a, 51b ... shaft support 55 ... intake side rocker shaft 56 as a rocker shaft ... Rocker shaft exhaust side rocker shafts 81, 86 ... washers 81a ... ring plate portion 81b ... annular projection 82 ... through hole 84 ... needle bearing 85 ... retainer 85a ... Washer holder
S: Annular space

Claims (5)

A camshaft (48) is rotatably supported on a pair of shaft support portions (51a, 51b) formed on a camshaft holder (51) provided on the cylinder head (24), and the camshaft (48) A rocker shaft (55, 56) having parallel axes is supported, and is disposed between the shaft support portions (51a, 51b) and is supported by the rocker shaft (55, 56) so as to be swingable. A rocker arm (49, 50) having a portion (49a, 50a) is interposed between the engine valve (43, 44) and the camshaft (48) disposed in the cylinder head (24) so as to be opened and closed. In the engine valve mechanism
Washers that allow the rocker shaft (55, 56) to pass between both ends of the arm main portion (49a, 50a) and the shaft support portions (51a, 51b) along the axial direction of the rocker shaft (55, 56). (81) are inserted,
As a two washers (81), the arm main portion (49a, 50a) and the the two shaft support portions (51a, 51b) ring plate portion interposed between (81a), among the ring plate portion (81a) It is formed so as to integrally have an annular protrusion (81b) that protrudes from the periphery and is press-fitted into the arm main part (49a, 50a) ,
The annular protrusions (81b) of the washers (81) are respectively inserted between the outer periphery of the rocker shaft (55, 56) and the inner periphery of the arm main part (49a, 50a), and both the annular protrusions. A rocker arm support structure in a valve operating mechanism for an engine, wherein the structure is spaced apart from each other in the axial direction so that an annular space (S) is formed between the portions (81b) . The inner diameter of the annular protrusion (81b) that forms a through hole (82) that allows the rocker shaft (55, 56) to pass through the inner peripheral surface of the annular protrusion (81b) is the rocker shaft (55, 56). rocker arm support structure in claim 1, wherein the engine valve operating mechanism, characterized in that it is set so as to sliding contact with the outer peripheral surface of the. The rocker arm support structure in a valve operating mechanism for an engine according to claim 1 or 2 , wherein the washer (81) is made of resin. A camshaft (48) is rotatably supported on a pair of shaft support portions (51a, 51b) formed on a camshaft holder (51) provided on the cylinder head (24), and the camshaft (48) A rocker shaft (55, 56) having parallel axes is supported, and is disposed between the shaft support portions (51a, 51b) and is supported by the rocker shaft (55, 56) so as to be swingable. A rocker arm (49, 50) having a portion (49a, 50a) is interposed between the engine valve (43, 44) and the camshaft (48) disposed in the cylinder head (24) so as to be opened and closed. In the engine valve mechanism
Washers (86) for allowing the rocker shafts (55, 56) to pass through are respectively interposed between the arm main portions (49a, 50a) and the shaft support portions (51a, 51b), and the arm main portions (49a, 50a). ) And the needle bearing (84) interposed between the rocker shafts (55, 56) and the retainer (85) which is a separate part from the washer (86) , the rocker shaft (55, 56) A washer holding portion (85a) that protrudes from both ends of the arm main portion (49a, 50a) along the axial direction and is inserted into the inner periphery of the washer (86) to hold the washer (86) is integrally formed. A rocker arm support structure in a valve operating mechanism for an engine. The protruding length of the washer holding portion (85a) from both ends of the arm main portion (49a, 50a) along the axial direction of the rocker shaft (55, 56) is the axis of the rocker shaft (55, 56). The rocker arm support structure in a valve operating mechanism for an engine according to claim 4 , characterized in that the thickness is set smaller than the thickness of the washer (86) along the direction.

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