JP2007092831A - Tensioner lifter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tensioner lifter provided with a housing having a sliding hole and fixed on a supporting body, a cylindrical plunger fitted into the sliding hole slidably, a cap mounted at a tip of the plunger so as to be abutted on a chain tensioner, and a holding member having a male screw part screw-fitted into a female screw part provided at the inner periphery of the plunger at the outer periphery and abutted on an end wall of the housing to realize smooth travel of the plunger onto a side for pushing a tensioner and suppress travel of a side where the plunger is pushed in by a simple structure. <P>SOLUTION: A spring 37 for energizing the plunger 34 onto the side for pushing the chain tensioner by the cap 35 is provided between the holding member 36 and the plunger 34. A flank angle α of a first flank 51 being a side where load of the spring 37 acts among flanks in the female screw part 49 and the male screw part 50 is set larger than a flank angle β of the second flank 52 being the opposite side to the first flank 51. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention has a housing that has a sliding hole in which one end is opened and an end wall is provided at the other end and is fixed to a support, and a cylindrical plunger that is slidably fitted in the sliding hole A cap that is attached to the tip of the plunger so as to abut against the chain tensioner, and a male threaded portion that engages with a female threaded portion that is provided on the inner circumference of the plunger. The present invention relates to a tensioner lifter provided with a holding member.

Such a tensioner lifter is already known, for example, from US Pat.
Japanese Patent Laid-Open No. 10-19095

  In the one disclosed in Patent Document 1, the plunger is hydraulically biased toward the tensioner tension side, the screw shaft is screwed onto the plunger, and a spring is interposed between the plunger and the screw shaft. In order to prevent the plunger at the time of stopping from being pushed in, and to make the plunger move quickly while compensating for a lack of hydraulic pressure when the engine is restarted, a male thread portion provided on the holding member and the plunger and screwed together, and Of the flank of the female thread portion, the flank angle of the first flank on which the spring load provided between the holding member and the plunger acts is the flank angle of the second flank on the opposite side of the first flank. Is set smaller than.

  However, such a tensioner lifter disclosed in Patent Document 1 requires hydraulic pressure, which complicates the structure.

  The present invention has been made in view of such circumstances, and provides a tensioner lifter capable of smoothing the movement of the plunger toward the side where the tensioner is pushed with a simple structure and suppressing the movement on the side where the plunger is pushed. The purpose is to do.

  In order to achieve the above-mentioned object, the invention according to claim 1 includes a housing that has a sliding hole that is open at one end and provided with an end wall at the other end and is fixed to a support, and the sliding hole. A cylindrical plunger that is slidably fitted, a cap that is attached to the tip of the plunger so as to be in contact with the chain tensioner, and a male screw that is screwed into a female screw provided on the inner periphery of the plunger A tensioner lifter comprising an outer periphery and a holding member that comes into contact with the end wall, and a spring that biases the plunger between the holding member and the plunger toward the side that presses the chain tensioner with the cap. The flank angle of the first flank, which is the side of the flank of the female screw portion and the male screw portion, on which the load of the spring acts, is the first flank. Characterized in that it is set larger than the second flank flank angle of the opposite side.

  According to a second aspect of the present invention, in addition to the configuration of the first aspect of the present invention, the cap is mounted on the tip of the plunger via a bearing member so as to be relatively rotatable.

  Further, the invention according to claim 3 is related to the plunger in order to prevent relative rotation of the plunger with respect to the holding member on the end wall and the holding member in addition to the configuration of the invention according to claim 1 or 2. An insertion hole through which a mating tool is removably inserted is provided.

  According to the first aspect of the present invention, the plunger is urged toward the side tensioning the chain tensioner by the spring force of the spring interposed between the holding member and the plunger, and the internally threaded portion of the plunger and the holding member screwed together. The flank angle of the first flank on which the spring load acts on the flank of the male thread portion is set to be larger than the flank angle of the second flank opposite to the first flank. The movement of the plunger toward the side that tensions the chain tensioner is facilitated by the first flank with a gentle inclination, and the movement of the plunger toward the side that is pushed in by the load action from the chain tensioner causes the second flank with a strong inclination. The plunger moves to the side that pushes the chain tensioner with a simple structure that does not use hydraulic pressure. It is possible to suppress the movement of the side of the plunger is pushed together to smooth.

  According to the second aspect of the present invention, the plunger moves in the axial direction while rotating by the mutual screwing of the holding member and the plunger. The plunger rotates smoothly, and the plunger rotates. Can be prevented from being transmitted to the chain tensioner through the cap.

  Furthermore, according to the invention described in claim 3, when the tensioner lifter is assembled to the support body, it is possible to assemble the plunger so that the plunger does not rotate by the spring force of the spring, and the assemblability can be improved. .

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on one embodiment of the present invention shown in the accompanying drawings.

  1 to 4 show an embodiment of the present invention, FIG. 1 is a longitudinal side view of an internal combustion engine, FIG. 2 is an enlarged view of a main part of FIG. 1, and FIG. 3 is an enlarged sectional view of a tensioner lifter. 4 is a cross-sectional view corresponding to FIG. 3 when assembled.

  First, in FIG. 1, an engine main body 11 of this internal combustion engine includes a crankcase 12 that rotatably supports a crankshaft 16, a cylinder body 13 that is coupled to the crankcase 12, and a cylinder that is coupled to the cylinder body 13. A head 14 and a head cover 15 coupled to the cylinder head 14, and a camshaft 17 having an axis parallel to the axis of the crankshaft 16, a holder 18 provided on the cylinder head 14, and the holder A holder cap 19 fastened to 18 is rotatably supported.

  Rotational power from the crankshaft 16 is transmitted to the camshaft 17 by being reduced by a half by a timing transmission mechanism 20, and the timing transmission mechanism 20 is fixed to the crankshaft 16. The driving sprocket 21, a driven sprocket 22 fixed to one end of the camshaft 17, and an endless cam chain 23 wound around the driving sprocket 21 and the driven sprocket 22.

  By the way, 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 slack side, which is the side fed from the drive sprocket 21, of the cam chain 23 between the drive sprocket 21 and the driven sprocket 22. A tensioner lifter 26 that is in contact with the chain tensioner 25 from the side opposite to the cam chain 23 is attached to the cylinder body 13. A cam chain guide 27 is brought into contact with the outer periphery of the tension side, which is the side pulled by the drive sprocket 21, of the cam chain 23 between the drive sprocket 21 and the driven sprocket 22.

  The cam chain guide 27 is formed of a synthetic resin having appropriate rigidity and elasticity so as to form a substantially arc shape along the cam chain 23 side. One end portion 27a which is the end portion of the cam chain guide 27 on the crankshaft 16 side is fitted upward and supported by a support recess 28 provided in the crankcase 12. Further, a support surface 27b facing the opposite side of the cam chain 23 is formed on the other end side of the cam chain guide 27 on the camshaft 17 side, and a contact support portion 29 that contacts the support surface 27b is a cylinder. It protrudes from the head 14. Further, on the both sides of the cam chain guide 27 close to the support surface 27b, projections 30 with a circular cross section are integrally projected, and these projections 30 are formed on the coupling surface of the cylinder block 13 to the cylinder head 14. It fits into the provided recesses 31... And is sandwiched between the cylinder block 13 and the cylinder head 14.

  Referring also to FIG. 2, the chain tensioner 25 is formed in an arch shape so that a convex curved surface is slidably contacted with the outer periphery of the cam chain 23, and one end of the chain tensioner 25 on the crankshaft 16 side is The crankcase 12 is rotatably supported via the pivot 32.

  A tensioner lifter 26 abuts on the chain tensioner 25 from the opposite side of the cam chain 23 in order to give tension to the slack side of the cam chain 23. The tensioner lifter 26 is fixed to the cylinder body 13 as a support. A housing 33 slidably fitted to the housing 33, a cap 35 attached to the tip of the plunger 34 so as to abut the chain tensioner 25, and a screw on the inner periphery of the plunger 34. And a holding member 36 that is in contact with and supported by the housing 33, and a coiled spring 37 interposed between the holding member 36 and the plunger 34.

  With further reference to FIG. 3, the housing 33 is formed by integrating a bottomed cylindrical portion 33 a having one end opened and a flange portion 33 b projecting radially outward from the other end of the bottomed cylindrical portion 33 a. A bottomed cylindrical portion 33a is inserted into a mounting hole 39 provided in the cylinder body 13 with an inner end opened in a chain running passage 38 provided in the cylinder body 13 for running the cam chain 23. The flange portion 33b is fastened to a mounting seat 40 provided in the cylinder body 13 around the outer end opening of the mounting hole 39 by a plurality of bolts 41, 41. 13 is attached.

  The bottomed cylindrical portion 33a is formed with a sliding hole 43 that opens one end, that is, the end on the chain tensioner 25 side, and has an end wall 42 provided on the other end side, and is a cylindrical plunger 34. Is slidably fitted into the sliding hole 43.

  A partition wall 34a is integrally provided near the distal end of the plunger 34, that is, near the cap 35 so as to form a fitting recess 44 in which a small diameter portion 35a included in the cap 35 is rotatably fitted. In addition, an O-ring 46 as a bearing member is mounted on the inner surface of the plunger 34 in the fitting recess 44, and this O-ring 46 engages with an annular groove 47 provided on the outer periphery of the small-diameter portion 35a. That is, the cap 35 is attached to the distal end of the plunger 34 via the O-ring 46 so as to be relatively rotatable, and the O-ring 46 is prevented from being detached from the distal end of the plunger 34.

  The holding member 36 is formed in a bottomed cylindrical shape with the partition wall 34 a side of the plunger 34 opened, and is inserted coaxially into the plunger 34. The closed end of the holding member 36 is the end wall 42 of the housing 33. The end wall 42 is abutted and supported so as to be fitted into a support recess 48 provided at the center.

  In addition, a female screw 49 is formed on the inner periphery of the plunger 34 on the holding member 36 side of the end wall 34a, and a male screw 50 is formed on the outer periphery of the holding member 36 so as to be screwed into the female screw 49. Is contracted between the partition wall 34 a of the plunger 34 and the closed end of the holding member 36. Thus, due to the spring force of the spring 37, the plunger 34 is urged in the direction in which the cap 35 is pressed against the chain tensioner 25, and the holding member 36 is urged in the direction in which it is pressed against the end wall 42 of the housing 33.

  By the way, in the female screw portion 49 and the male screw portion 50, the flank angle α of the first flank 51, which is the side on which the load of the spring 37 acts, of the flank is opposite to the first flank 51. The second flank 52 is formed in a sawtooth shape that is set larger than the flank angle β.

  Further, through holes 53 and 54 are provided in the closed end of the end wall 42 of the housing 33 and the holding member 36, and a tool 55 having a rod shape is inserted into the through holes 53 and 54, as shown in FIG. It can be inserted in a removable manner. In addition, the partition wall 34a of the plunger 34 is provided with an engagement groove 57 for releasably engaging the tool 55. By holding the tool 55 engaged with the engagement groove 57, the plunger 34 with respect to the holding member 36 is provided. The cross-sectional shape of the tool 55 and the insertion hole 54 may be formed so that the rotation of the tool 55 can be prevented when the tool 55 is inserted. Further, in order to close the insertion hole 53 with the lid member 56 in a state where the tool 55 is not inserted, a female screw may be provided on the inner surface of the insertion hole 53.

  Next, the operation of this embodiment will be described. Between the holding member 36 of the tensioner lifter 26 and the plunger 34, a spring 37 for biasing the plunger 34 is interposed on the side where the chain tensioner 25 is pressed by the cap 35. Of the flank of the internal thread portion 49 provided on the inner periphery of the plunger 34 and the external thread portion 50 provided on the outer periphery of the holding member 36 so as to be screwed to the internal thread portion 49, the load on the spring 37 acts. The flank angle α of the first flank 51 is set larger than the flank angle β of the second flank 52 on the side opposite to the first flank 51.

  That is, the plunger 34 is biased to the side that tensions the chain tensioner 25 by the spring force of the spring 37 interposed between the holding member 36 and the plunger 34, but the first is the side on which the load of the spring 37 acts. Since the flank angle α of the flank 51 is larger than the flank angle β of the second flank 52, the movement of the plunger 34 toward the side that tensions the chain tensioner 25 is facilitated by the first flank 51 having a gentle inclination. The movement of the plunger 34 to the side pushed by the load action from the chain tensioner 25 can be suppressed by the second flank 52 having a tight inclination, and the side that pushes the chain tensioner 25 with a simple structure that does not use hydraulic pressure. The movement of the plunger 34 to the side and the movement on the side where the plunger 34 is pushed Can be suppressed.

  The cap 35 that contacts the chain tensioner 25 is attached to the tip of the plunger 34 via an O-ring 46 so as to be relatively rotatable, and the plunger 34 rotates while the holding member 36 and the plunger 34 are screwed together. When moving in the axial direction, the rotation operation of the plunger 34 can be smoothed and the rotation operation of the plunger 34 can be prevented from being transmitted to the chain tensioner 25 via the cap 35.

  Further, a tool 55 that engages with an engaging groove 57 of the plunger 34 is removably inserted into the end wall 42 of the housing 33 and the closed end of the holding member 36 to prevent relative rotation of the plunger 34 with respect to the holding member 36. Since the insertion holes 53 and 54 are provided, when the tensioner lifter 26 is assembled to the cylinder body 13, it is possible to assemble the plunger 34 so that the plunger 34 does not rotate by the spring force of the spring 37, thereby improving the assemblability. be able to.

  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. It is.

It is a vertical side view of an internal combustion engine. It is a principal part enlarged view of FIG. It is an expanded sectional view of a tensioner lifter. It is sectional drawing corresponding to FIG. 3 at the time of an assembly | attachment.

Explanation of symbols

13 ... Cylinder body 25 as a support body ... Chain tensioner 26 ... Tensioner lifter 33 ... Housing 34 ... Plunger 35 ... Cap 36 ... Holding member 37 ... Spring 42- ··· End wall 43 ··· Sliding hole 46 ··· O-ring 49 which is a bearing member ··· Female screw portion 50 · · · Male screw portion 51 ··· First flank 52 · · · Second flank 53 54 ... Insertion hole 55 ... Tool α ... Flank angle of first flank β ... Frank angle of second flank

Claims (3)

  A housing (33) having a sliding hole (43) provided with an end wall (42) at the other end and an end wall (42) provided at the other end and fixed to the support (13), and sliding on the sliding hole (43). A cylindrical plunger (34) that is movably fitted, a cap (35) that is attached to the tip of the plunger (34) so as to contact the chain tensioner (25), and the plunger (34) The tensioner lifter comprising: a holding member (36) that has a male screw portion (50) that is screwed into a female screw portion (49) provided on an inner periphery on the outer periphery and is in contact with the end wall (42); A spring (37) for biasing the plunger (34) is interposed between the member (37) and the plunger (34) on the side of the cap (35) that presses the chain tensioner (25). Part (4 ) And the flank angle (α) of the first flank (51) on the side on which the load of the spring (37) acts is the flank of the male thread portion (50). A tensioner lifter characterized in that it is set larger than the flank angle (β) of the second flank (52) on the opposite side.   The tensioner lifter according to claim 1, wherein the cap (35) is attached to the tip of the plunger (34) via a bearing member (46) so as to be relatively rotatable.   A tool (55) engaged with the plunger (34) is inserted into the end wall (42) and the holding member (36) to prevent relative rotation of the plunger (34) with respect to the holding member (36). The tensioner lifter according to claim 1 or 2, further comprising an insertion hole (53, 54) for removably inserting the tensioner lifter.

Images