JP2019112962A - Screw-type tensioner lifter for internal combustion engine - Google Patents

Abstract

To suppress generation of noise by avoiding return of a pressing body even in a case where an alternating load caused by a reaction force from a transmission belt acts in a screw-type tensioner lifter for an internal combustion engine comprising: the pressing body in which a female screw is engraved in an inner periphery and capable of applying a pressing force to the transmission belt; a casing fixed to an engine body; a shaft receiving member interposed between a shaft and the casing in such a manner that the shaft is thrust-supported in a rotatable manner; and an elastic member provided between the casing and the shaft for rotating and energizing the shaft.SOLUTION: A shaft 35 integrally includes: a screw part 35a in which a male screw 48 to be threaded to a female screw 41 is engraved in an outer periphery; a supported part 35b including an abutment surface 49 to be abutted to a shaft receiving member 37 in a direction along an axial line of the shaft 35, and formed with a larger diameter than the screw part 35a; and a coupling axis part 35c coaxially connecting the screw part 35a and the supported part 35b. A minimum inner diameter D1 of the abutment surface 49 is set larger than an outer diameter D2 of the screw part 35a.SELECTED DRAWING: Figure 2

Description

  The present invention is a pressing body which is formed at least partially in a cylindrical shape so that a female screw is engraved on the inner periphery and which can apply a pressing force to a transmission belt traveling in an engine main body, A shaft screwed to the female screw, a casing fixed to the engine body, and a shaft receiver rotatably supported between the shaft and the casing by thrusting the shaft rotatably from the side opposite to the pressing body The present invention relates to a screw tensioner lifter for an internal combustion engine, comprising: a member; and an elastic member provided between the casing and the shaft while rotationally biasing the shaft in a direction in which the pressing body advances toward the transmission band.

  A screw type tensioner for an internal combustion engine in which a shaft screwed to a pressing body for applying a pressing force to a cam chain which is a transmission belt is thrust supported via a shaft receiving member to a casing attached to an engine body. Lifters are already known, for example from US Pat.

JP 2001-50056 A

  In the above-mentioned Patent Document 1, the outer diameter of the contact surface of the shaft to the shaft receiving member is set smaller than the outer diameter of the screw portion of the shaft so as to be screwed to the pressing body. When the rotational force is applied to the shaft by the screw diameter of the female screw by the reaction force from the cam chain, the effective friction area to overcome the rotational force can not be secured at the contact portion of the shaft to the shaft receiving member is there. In that case, the cam chain tensioner in sliding contact with the cam chain may not remain at the position where it should be originally contained, and noise may eventually be generated.

  The reaction force generated by the overcoming reaction force of the cam chain generated inside the engine body of the internal combustion engine is not a constant force pushing in one direction, but is an alternating load generated along with the opening and closing of the intake valve and the exhaust valve. The shaft pressed by the cam chain reaction force due to this alternating load balances the friction force with the shaft receiving member with the coefficient of static friction to give an appropriate cam chain tension to the cam chain. There is known a physical phenomenon that when the load is applied, the static friction coefficient is instantaneously lifted as a result of the inertia force at the screwing portion of the pressing body and the shaft, and the static friction coefficient apparently decreases. For this reason, the static friction coefficient inside the screw type tensioner lifter during the operation of the internal combustion engine becomes smaller than the static friction coefficient measured statically, and the press body loses the cam chain reaction force, as described above. There is a fact that it has caused the generation of abnormal noise.

  The present invention has been made in view of such circumstances, and is an internal combustion engine capable of avoiding generation of abnormal noise by avoiding return of a pressing body even if an alternating load by reaction force from a transmission belt acts. It is an object of the present invention to provide a screw type tensioner lifter.

  In order to achieve the above object, the present invention is to apply a pressing force to a transmission band which is formed at least in part in a cylindrical shape so that a female screw is formed on the inner periphery and which travels in an engine body. , A shaft screwed to the female screw, a casing fixed to the engine main body, and the shaft rotatably supported by the shaft from the opposite side of the pressing body to support the shaft and the casing Internal combustion engine comprising: a shaft receiving member interposed therebetween; and an elastic member provided between the casing and the shaft while urging the shaft in a direction in which the pressing body advances toward the transmission band side. In a screw type tensioner lifter of an engine, the shaft is a screw portion in which an external thread to be engaged with the internal thread is engraved on the outer periphery, and the shaft is in a direction along the axis of the shaft. A supported portion having a contact surface that abuts a shaft receiving member and is formed larger in diameter than the screw portion, and a connecting shaft portion connecting the screw portion and the supported portion coaxially are integrally provided. The first feature is that the minimum inner diameter of the contact surface is set larger than the outer diameter of the screw portion.

  Further, according to the present invention, in addition to the configuration of the first feature, in the shaft receiving member, a cylindrical side wall portion surrounding at least a part of the outer periphery of the supported portion, and a support hole formed in the casing A support shaft portion is provided integrally with a cylindrical support cylinder portion to be inserted, has a diameter smaller than the outer diameter of the screw portion, projects coaxially from the supported portion, and is inserted into the support cylinder portion. The gap provided between the outer periphery of the support shaft portion and the inner periphery of the support cylindrical portion is provided on the shaft and set smaller than the gap between the inner periphery of the side wall portion and the outer periphery of the supported portion. It is the feature of

  In the present invention, in addition to the configuration of the second feature, the contact surface is formed on an end face of the supported portion opposite to the connection shaft portion, and the inner diameter is larger than the outer diameter of the screw portion. According to a third feature of the present invention, an annular recess having an outer circumferential surface is formed so as to surround the support shaft while defining the inner peripheral edge of the contact surface.

  In the present invention, in addition to the configuration of the second or third feature, the axial length of the support shaft portion in the support cylindrical portion is set to be larger than the outer diameter of the support shaft portion. 4 features.

  In the present invention, in addition to any of the configurations of the second to fourth features, the maximum outer diameter of the supported portion is larger than the outer diameter of the screw portion, and three times the outer diameter of the screw portion. The fifth feature is to be set as follows.

  Furthermore, according to the present invention, in addition to any of the configurations of the second to fifth features, a slot is formed on at least the support shaft portion of the shaft and the support cylindrical portion of the shaft receiving member. The sixth feature.

  According to the first feature of the present invention, the external diameter formed on the supported portion of the shaft and in contact with the shaft receiving member and having the minimum inner diameter is inscribed on the outer periphery screwed to the internal thread of the pressing body. Since the load applied to the shaft is received by the shaft receiving member with a diameter larger than the diameter of the screwing portion of the pressing body and the shaft because the diameter is larger than the outer diameter of the screw portion, the area receiving the shaft by the shaft receiving member is sufficient. By increasing the size, an effective friction area sufficient to overcome the rotational force due to the alternating load is secured at the contact portion of the shaft to the shaft receiving member even in the state where the alternating load from the transmission belt is applied Can be suppressed.

  According to a second feature of the present invention, the shaft receiving member is integrally provided with a cylindrical side wall portion and a cylindrical support cylindrical portion fitted into the support hole of the casing, and the outer diameter of the screw portion The gap between the outer periphery of the support shaft and the inner periphery of the support cylinder, which is smaller than the smaller diameter and coaxially protrudes from the supported portion of the shaft and is inserted into the support cylinder, is the inner periphery of the side wall and the supported portion The shaft is smaller than the gap between the outer peripheries of the shaft, so that the shaft can be supported by the shaft support member with a diameter smaller than the outer diameter of the screw. It is possible to hold the stabilization of the behavior with a small frictional force while avoiding an unstable posture such as tilting due to inertial force.

  According to the third feature of the present invention, the annular recess which defines the inner peripheral edge of the contact surface is formed on the end face opposite to the connection shaft of the supported portion, and the inner diameter of the annular recess is the outer diameter of the threaded portion Since it is larger than the above, the area of the contact surface can be enlarged while the structure in which the minimum inner diameter of the contact surface is larger than the outer diameter of the screw portion is simply formed, and the generation of noise can be effectively suppressed.

  According to the fourth feature of the present invention, since the axial length of the support shaft in the support cylinder is larger than the outer diameter of the support shaft, the support of the support shaft by the support cylinder and hence the shaft is stabilized. Can be

  According to the fifth feature of the present invention, since the maximum outer diameter of the supported portion is larger than the outer diameter of the screw portion and not more than three times the outer diameter of the screw portion, the supported portion is excessively large in the radial direction The area of the contact surface can be sufficiently secured while avoiding the increase in size.

  Further, according to the sixth aspect of the present invention, the shaft and the shaft receiver can be utilized by utilizing the grooving of at least the support shaft portion of the shaft and the support cylindrical portion of the shaft receiving member. Refueling between members can be facilitated.

It is a vertical side view of the main part of an engine of a 1st embodiment. It is an expanded sectional view of a screw type tensioner lifter. It is sectional drawing of the screw type tensioner lifter of 2nd Embodiment.

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

  A first embodiment of the present invention will be described with reference to FIGS. 1 and 2. First, in FIG. 1, an engine body 11 of an internal combustion engine E mounted on a motorcycle, for example, rotatably rotates a crankshaft 16. A crankcase 12 for supporting, a cylinder body 13 coupled to the crankcase 12, a cylinder head 14 coupled to the cylinder body 13, and a head cover 15 coupled to the cylinder head 14. A camshaft 17 having an axis parallel to the axis of the crankshaft 16 is rotatably supported by a holder 18 provided on the cylinder head 14 and a holder cap 19 fastened to the holder 18.

  The rotational power from the crankshaft 16 is decelerated to 1/2 by the timing transmission mechanism 20 and transmitted to the camshaft 17. The timing transmission mechanism 20 is fixed to the crankshaft 16. It comprises a drive sprocket 21, a driven sprocket 22 fixed to one end of the camshaft 17, and a cam chain 23 as an endless transmission band wound around the drive sprocket 21 and the driven sprocket 22.

  The drive sprocket 21 rotates in the direction indicated by the arrow 24, and a chain tensioner 25 is provided on the outer periphery of the cam chain 23 between the drive sprocket 21 and the driven sprocket 22 which is the side fed out from the drive sprocket 21. A screw type tensioner lifter 26 in contact with the chain tensioner 25 from the opposite side of the cam chain 23 is attached to the cylinder body 13 of the engine body 11. Further, a cam chain guide 27 is in contact with the tension-side outer periphery of the cam chain 23 between the drive sprocket 21 and the driven sprocket 22 which is pulled by the drive sprocket 21.

  The cam chain guide 27 is formed of a synthetic resin having appropriate rigidity and elasticity so as to form a substantially arcuate shape along the cam chain 23 side. One end 27a, which is the crankshaft 16 side end of the cam chain guide 27, opens upward and is fitted and supported in a support recess 28 provided on the crankcase 12. Further, on the other end side of the cam chain guide 27 that is the camshaft 17 side, a support surface 27b facing the opposite side to the cam chain 23 is formed, and the contact support shaft 29 that contacts the support surface 27b is The cylinder head 14 is provided in a protruding manner. Further, on the both sides of the cam chain guide 27 near the support surface 27b, protrusions 30 having a circular cross-section are integrally projected on both sides, and the protrusions 30 are provided on the connecting surface of the cylinder body 13 to the cylinder head 14. It is fitted in the recess 31 and sandwiched between the cylinder body 13 and the cylinder head 14.

  Further, the chain tensioner 25 is formed in an arched shape such that a convex curved surface is in sliding contact with the outer periphery of the cam chain 23 on the loose side, and one end of the chain tensioner 25 on the crankshaft 16 side is cranked via a pivot shaft 32. It is rotatably supported by the case 12.

  In order to apply tension to the loose side of the cam chain 23, the pressing body 34 of the screw type tensioner lifter 26 is abutted against the chain tensioner 25 from the side opposite to the cam chain 23.

  Referring also to FIG. 2, the screw type tensioner lifter 26 is formed at least in part in a cylindrical shape so that an internal thread 41 is engraved on the inner periphery, and a pressing force is applied to the cam chain 23. , A shaft 35 screwed to the female screw 41, a casing 36 fixed to the cylinder body 13 of the engine main body 11, and the shaft 35 opposite to the pressing body 34 And the shaft receiving member 37 interposed between the shaft 35 and the casing 36 so as to rotatably support the shaft 35 and the shaft 35 in the direction in which the pressing body 34 advances toward the cam chain 23 side. Are rotatably biased to provide a spring 38 as an elastic member provided between the casing 36 and the shaft 35.

  In this embodiment, the pressing body 34 is formed by attaching a cap 40 to be in contact with the chain tensioner 25 at one end of a cylindrical cylindrical member 39, and a female screw is formed on the inner periphery of the cylindrical member 39. 41 is engraved.

  The casing 36 has a cylindrical portion 36a whose one end (inner end) is open on the side of the cam chain passage 42 (see FIG. 1) formed in the engine main body 11 to run the cam chain 23, and its cylinder An end wall portion 36b for closing the other end portion (outer end portion) of the portion 36a and a flange portion 36c projecting radially outward from the end wall portion 36b are integrally formed. On the other hand, the cylinder body 13 is provided with a mounting hole 43 into which the cylindrical portion 36a is inserted, and the mounting seat 44 provided on the cylinder body 13 around the outer end opening of the mounting hole 43 The flange portion 33 c is fastened by a plurality of bolts 45. At one end of the cylindrical portion 36 a of the casing 36, a guide member 46 for guiding the axial movement of the cylindrical member 39 in the pressing body 34 is attached by a C-shaped snap ring 47.

  The shaft 35 has a screw portion 35a on the outer periphery of which a male screw 48 screwed to the female screw 41 is formed, and an abutment surface 49 abutting on the shaft receiving member 37 in a direction along the axis of the shaft 35 A supported portion 35b having a diameter larger than that of the threaded portion 35a, a connecting shaft portion 35c coaxially connecting between the threaded portion 35a and the supported portion 35b, and coaxially protruding from the supported portion 35b The support shaft portion 35d is formed integrally with the support shaft portion 35d.

  The spring spring 38 is disposed so as to surround a part of the connecting shaft portion 35c between the supported portion 35b and the washer 50 which abuts on the other end of the cylindrical member 39 in the pressing body 34. And the cylindrical portion 36a of the casing 36 and the connecting shaft portion 35c.

  The shaft receiving member 37 is a cup washer, and a ring plate-shaped receiving plate portion 37a which abuts a part of the contact surface 49, and the supported portion continuously connected to the outer periphery of the receiving plate portion 37a. A cylindrical side wall portion 37b surrounding at least a part of the outer periphery of the 35b (the entire outer periphery in this embodiment) and an inner periphery of the receiving plate portion 37a are extended perpendicularly to the side wall portion 37b. It is formed to integrally have a cylindrical support cylinder 37c.

  On the other hand, in the end wall portion 36b of the casing 36, the receiving recess portion 41 for receiving the receiving plate portion 37a and the side wall portion 37b of the shaft receiving member 37 and the support cylindrical portion 37c are fitted. A support hole 42 coaxially connected to the housing recess 41 is provided.

  The contact surface 49 of the supported portion 35b is ring-shaped so as to contact the receiving plate portion 37a of the shaft receiving member 37c at the end face of the supported portion 35b opposite to the connecting shaft portion 35c. The minimum inner diameter D1 of the contact surface 49 is set larger than the outer diameter D2 of the threaded portion 35a.

  Moreover, the maximum outer diameter D3 of the supported portion 35b is set to be larger than the outer diameter D2 of the screw portion 35a and equal to or less than three times the outer diameter D1 of the screw portion 35a.

  Further, on the end face of the supported portion 35b opposite to the connecting shaft portion 35c, an annular recess 53 surrounding the support shaft portion 35d while defining the inner peripheral edge of the contact surface 49 is outside the screw portion 35a. It is formed to have an inner diameter larger than the diameter D2, that is, the minimum inner diameter D1 of the contact surface 49.

  The support shaft portion 35d of the shaft 35 has a diameter smaller than the outer diameter D1 of the screw portion 35a, protrudes coaxially from the supported portion 35b, and is inserted into the support cylindrical portion 37c of the shaft receiving member 37. The gap d1 between the outer periphery of the support shaft portion 35d and the inner periphery of the support cylindrical portion 37c is between the inner periphery of the side wall portion 37b of the shaft receiving member 37 and the outer periphery of the supported portion 35b. It is set smaller than the gap d2. The axial length L1 of the support shaft 35d in the support cylindrical portion 37c is set larger than the outer diameter D4 of the support shaft 35d.

  Along a diameter line from at least a support shaft 35d of the shaft 35, and in this embodiment, from the support shaft 35d through the supported portion 35b to an intermediate portion of the connection shaft 35c, A slot 54 is formed. A flat stopper 55 can be engaged with the slot 54 before the cap 40 of the pressing body 34 abuts on the chain tensioner 25 to prevent the rotation of the shaft 35, At the outer end opening edge of the support hole 52, two pairs of locking recesses 56 for engaging the stopper 55 are arranged such that the locking recesses 56 of each set are arranged on the diameter line of the support hole 52. It is formed.

  After removing the stopper 55 after the cap 40 of the pressing body 34 abuts on the chain tensioner 25, the plug member 57 is screwed into the outer end portion of the support hole 52. Further, a slit 58 is formed on the support cylindrical portion 37c of the shaft receiving member 37 over the entire length thereof.

  Next, the operation of the first embodiment will be described. The shaft 35 of the screw type tensioner lifter 26 has a threaded portion 35a on the outer periphery of which an external thread 48 engaged with the internal thread 41 of the pressing body 34 is engraved A supported portion 35b having an abutment surface 49 that abuts the shaft receiving member 37 in a direction along the axis of the shaft 35 and is formed larger in diameter than the screw portion 35a, the screw portion 35a and the supported portion Since the connecting shaft portion 35c coaxially connecting between 35b is integrally formed, and the minimum inner diameter D1 of the contact surface 49 is set larger than the outer diameter D2 of the screw portion 35a, the pressing body 34 and the shaft 35 The shaft receiving member 37 receives the load applied to the shaft 35 with a diameter larger than the diameter of the screwing portion of the shaft, while the area for receiving the shaft 35 by the shaft receiving member 37 is sufficiently large. Therefore, even when an alternating load from the cam chain 23 is applied, the contact portion of the shaft 35 to the shaft receiving member 37 secures an effective friction area sufficient to overcome the rotational force due to the alternating load. It is possible to suppress the generation of sound.

  Further, in the shaft receiving member 37, a cylindrical side wall portion 37b surrounding at least a part of the outer periphery of the supported portion 35b, and a cylindrical support cylindrical portion 37c fitted in the support hole 52 formed in the casing 36. Are integrally provided, and the shaft 35 is provided with a support shaft 35d which protrudes coaxially from the supported portion 35b with a diameter smaller than the outer diameter D2 of the screw 35a and which is inserted into the support cylindrical portion 37c. Since the gap d1 between the outer periphery of the support shaft 35d and the inner periphery of the support cylindrical portion 37c is set smaller than the gap d2 between the inner periphery of the side wall 37b and the outer periphery of the supported portion 35b. By supporting the support shaft portion 35d smaller in diameter than the outer diameter of the screw portion 35a by the shaft receiving member 37, even under an alternating load of any frequency depending on the engine speed, While avoiding that the bets 35 in an unstable posture such that tilting inertial force, it is possible to retain the stabilization of behavior with a small frictional force.

  Further, the contact surface 49 is formed on the end face of the supported portion 35b opposite to the connecting shaft portion 35c, and the annular recess 53 having an inner diameter larger than the outer diameter of the screw portion 35a Since it is formed to surround the support shaft portion 35d while defining the inner peripheral edge of the surface 49, the contact while simply configuring a structure in which the minimum inner diameter D1 of the contact surface 49 is larger than the outer diameter D2 of the screw portion 35a The area of the surface 49 can be increased to effectively suppress the generation of noise.

  Further, since the axial length L1 of the support shaft portion 35d in the support cylindrical portion 37c is set to be larger than the outer diameter D4 of the support shaft portion 35d, the support shaft portion 35d by the support cylindrical portion 37c and thus the shaft 35 support can be stabilized.

  Further, since the maximum outer diameter D3 of the supported portion 35b is larger than the outer diameter D2 of the screw portion 35a and not more than 3 times the outer diameter D2 of the screw portion 35a, the supported portion 35b becomes excessively large in the radial direction. The area of the contact surface 49 can be sufficiently secured while avoiding the problem.

  Further, since the splits 54, 58 are formed on at least the support shaft 35d of the shaft 35 and the support cylindrical portion 37c of the shaft receiving member 37, using the splits 54, 58 Refueling between the shaft 35 and the shaft receiving member 37 can be facilitated.

  Although the second embodiment of the present invention will be described with reference to FIG. 3, the parts corresponding to those of the first embodiment are only illustrated with the same reference numerals, and detailed description will be given I omit it.

  The screw type tensioner lifter 61 includes a pressing body 34 having a cap 40 attached to one end of a cylindrical cylindrical member 39 having a female screw 41 engraved on the inner periphery thereof, and a shaft 65 screwed to the female screw 41; A casing 66 fixed to the cylinder body 13 of the engine main body 11 and interposed between the shaft 65 and the casing 66 so as to rotatably support the shaft 65 rotatably from the opposite side to the pressing body 34 A shaft receiving member 67, and a spring as an elastic member provided between the casing 66 and the shaft 65 by rotationally urging the shaft 65 in a direction in which the pressing body 34 advances toward the cam chain 23 side. And a spring 38.

  The casing 66 integrally includes a cylindrical portion 66a, an end wall portion 66b closing an outer end portion of the cylindrical portion 66a, and a flange portion 66c projecting radially outward from the end wall portion 66b. Further, the shaft 65 has a screw portion 65a in which an external thread 48 engaged with the female screw 41 is engraved on the outer periphery, and an abutment surface 69 which abuts on the shaft receiving member 67 in the direction along the axis of the shaft 65 A supported portion 65b formed larger in diameter than the threaded portion 65a, a connecting shaft portion 65c connecting the threaded portion 65a and the supported portion 65b coaxially, and coaxially projecting from the supported portion 65b And the support shaft portion 65d.

  The contact surface 69 of the supported portion 65b is formed on the outer periphery of the supported portion 65b, and is formed in a tapered shape such that the connecting shaft portion 65c side has a large diameter. The minimum inner diameter D5 of the surface 69 is set larger than the outer diameter D2 of the screw portion 65a. The maximum outer diameter D6 of the supported portion 65b is set to be larger than the outer diameter D2 of the screw portion 65a and equal to or less than three times the outer diameter D1 of the screw portion 65a.

  The shaft receiving member 67 has a tapered receiving plate portion 67a which abuts a part of the contact surface 69, and a ring plate shape connected to the small diameter end of the receiving plate portion 67a and facing the supported portion 65b. The flat plate portion 67b is formed integrally with a cylindrical support cylindrical portion 67c which extends in a direction perpendicular to the inner periphery of the flat plate portion 67b and extends on the opposite side to the receiving plate portion 67a.

  A housing recess 71 for receiving the receiving plate portion 67a and the flat plate portion 67b of the shaft receiving member 67 and the support cylindrical portion 67c are fitted in the end wall portion 66b of the casing 66, and the housing recess A support hole 72 coaxially connected to 71 is provided.

  The support shaft portion 65d of the shaft 65 has a diameter smaller than the outer diameter D1 of the screw portion 65a and protrudes coaxially from the supported portion 65b, and is inserted into the support cylindrical portion 67c of the shaft receiving member 67. Be done. Moreover, the axial length L2 of the support shaft portion 65d in the support cylindrical portion 67c is set larger than the outer diameter D7 of the support shaft portion 65d.

  Between at least the support shaft portion 65d of the shaft 65, and in this embodiment, from the support shaft portion 65d to the intermediate portion of the connecting shaft portion 65c via the supported portion 65b, rubbing along a diameter line A split 74 is formed, and a flat stopper 75 can be engaged with the split 74 to prevent the rotation of the shaft 65, and the outer opening edge of the support hole 72 is formed. Two pairs of locking recesses 76 for engaging the stoppers 75 are formed so as to arrange each pair of locking recesses 76 on the diameter line of the support hole 72.

  After the stopper 75 is removed from the slot 74, the plug member 77 is screwed into the outer end of the support hole 72. Further, a slit 78 is formed on the support cylindrical portion 67c of the shaft receiving member 67 over the entire length thereof.

  According to the second embodiment, the minimum inner diameter D5 of the contact surface 69 formed in the supported portion 65 b of the shaft 65 and in contact with the shaft receiving member 67 in the direction along the axis of the shaft 65 is the shaft 65. The shaft receiving member 67 receives the load applied to the shaft 65 with a diameter larger than the diameter of the screwing portion of the pressing body 34 and the shaft 65 because the diameter is larger than the outer diameter D2 of the threaded portion 65a. By sufficiently enlarging the area for receiving the shaft 65, an effective friction area sufficient to overcome the rotational force due to the alternating load at the contact portion of the shaft 65 to the shaft receiving member 67 even in the acting state of the alternating load. By securing it, the generation of abnormal noise can be suppressed.

  Further, a support shaft portion 65d provided on the shaft 65 and having a smaller diameter than the outer diameter D2 of the screw portion 65a is fitted into the support cylindrical portion 67c of the shaft receiving member 67, and the support cylindrical portion 67c of the support shaft portion 65d is Since the axial length L2 of the support shaft portion 65d is larger than the outer diameter D7 of the support shaft portion 65d, it is possible to stabilize the support of the support shaft portion 65d and thus the shaft 65 by the support cylindrical portion 67c.

  Further, since the maximum outer diameter D3 of the supported portion 65b is larger than the outer diameter D2 of the screw portion 65a and not more than three times the outer diameter D2 of the screw portion 65a, the supported portion 65b becomes excessively large in the radial direction. The area of the contact surface 69 can be sufficiently secured while avoiding the problem.

  Further, since at least the support shaft portion 65d of the shaft 65 and the support cylindrical portion 67c of the shaft receiving member 67 are formed with the splits 74, 78, utilizing the splits 74, 78 Refueling between the shaft 65 and the shaft receiving member 67 can be facilitated.

  Moreover, since the contact surface 69 formed on the outer periphery of the supported portion 65b of the shaft 65 is formed in a tapered shape, the area of the contact surface 69 is avoided while avoiding the increase of the maximum outer diameter D6 of the supported portion 65. And the shaft 65 can be supported more stably.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment, A various design change is made, without deviating from this invention described in the claim. Is possible.

11 · · · Engine main body 23 · · · Drive band cam chain 26, 61 · · · Threaded tensioner lifter 35, 65 · · · Shaft 35a, 65a · · · Threaded portion 35b, 65b · · · · Supported portion 35c, 65c · · · Connecting shaft portion 35d, 65d · · · Support shaft portion 36, 66 · · · Casing 37, 67 · · · Shaft receiving member 37b · · · Side wall portion 37c · · · · Supporting cylindrical portion 38 · · · · Spring members 49, 69 that are elastic members · · · · Contact surface 41 · · · female screw 48 · · · male screw 52 · · · support hole 53 · · · annular recess 54, 58 · · · split d1 · · · The gap d2 between the outer periphery of the support shaft portion and the inner periphery of the support cylinder portion ... The gap D1, D5 between the inner periphery of the side wall portion and the outer periphery of the supported portion ... The minimum inner diameter D2 of the contact surface ... screw Outer diameter D3 of the part ... Maximum outer diameter D4 of the supported part ... Support The axial length of an outer diameter E · · · engine L1 · · · supporting cylindrical portion of the support shaft portion of the shaft portion

Claims (6)

  It is possible to apply a pressing force to the transmission belt (23) which is at least partially formed in a cylindrical shape so that the internal thread (41) is engraved on the inner circumference and which travels in the engine body (11) The pressing body (34), the shaft (35, 65) screwed to the female screw (41), the casing (36, 66) fixed to the engine body (11), and the shaft (35, 65) A shaft receiving member (37, 67) interposed between the shaft (35, 65) and the casing (36, 66) by thrusting rotatably rotatably from the side opposite to the pressing body (34); The casing (36, 66) and the shaft (35, 65) while rotationally urging the shaft (35, 65) in a direction in which the pressing body (34) advances toward the transmission band (23) Elasticity provided between In the screw type tensioner lifter of an internal combustion engine provided with a member (38), the shaft (35, 65) has a threaded portion (35a, 65) in which an external thread (48) engaged with the internal thread (41) is engraved. 65a) and an abutment surface (49, 69) that abuts the shaft receiving member (37, 67) in a direction along the axis of the shaft (35, 65) from the threaded portion (35a, 65a) A large diameter support portion (35b, 65b) and a connection shaft portion (35c, 65c) coaxially connecting the screw portion (35a, 65a) and the support portion (35b, 65b) Internal combustion internal combustion engine characterized in that the minimum inner diameter (D1, D5) of the contact surface (49, 69) is set larger than the outer diameter (D2) of the screw portion (35a, 65a) Engine screw type tensioner lifter   In the shaft receiving member (37), a cylindrical side wall (37b) surrounding at least a part of the outer periphery of the supported portion (35b), and a support hole (52) formed in the casing (36) A cylindrical support cylindrical portion (37c) to be inserted is integrally provided, has a diameter smaller than the outer diameter (D2) of the screw portion (35a), and coaxially protrudes from the supported portion (35b) A support shaft (35d) to be inserted into the support cylinder (37c) is provided on the shaft (35), and a gap between the outer periphery of the support shaft (35d) and the inner periphery of the support cylinder (37c) The screw according to claim 1, characterized in that d1) is set smaller than the gap (d2) between the inner periphery of the side wall portion (37b) and the outer periphery of the supported portion (35b). Type tensioner lifter.   The contact surface (49) is formed on the end face of the supported portion (35b) opposite to the connection shaft portion (35c), and is larger than the outer diameter (D2) of the screw portion (35a) The internal combustion engine according to claim 2, characterized in that an annular recess (53) having an inner diameter is formed to surround the support shaft (35d) while defining the inner peripheral edge of the contact surface (49). Screw type tensioner lifter.   An axial length (L1) of the support shaft (35d) in the support cylindrical portion (37c) is set to be larger than an outer diameter (D4) of the support shaft (35d). A screw type tensioner lifter for an internal combustion engine according to claim 2 or 3.   The maximum outer diameter (D3) of the supported portion (35b) is larger than the outer diameter (D2) of the screw portion (35a) and not more than three times the outer diameter (D2) of the screw portion (35a) The screw type tensioner lifter for an internal combustion engine according to any one of claims 2 to 4, which is set.   Grips (54, 58) are formed on at least the support shaft (35d) of the shaft (35) and the support cylinder (37c) of the shaft receiving member (37). The screw-type tensioner lifter of the internal combustion engine of any one of Claims 2-5.

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