JP2011027143A - Chain tensioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small chain tensioner releasing excessive pressure in a pressure chamber. <P>SOLUTION: In the chain tensioner 1, a plunger 10 is slidably inserted in a cylinder 9, an oil supply passage 21 guiding hydraulic fluid in the pressure chamber 20 surrounded by the plunger 10 and cylinder 9, a through-hole 24 communicating the pressure chamber 20 with the outside air is formed to the cylinder 9, a male screw member 26 is screwed into a female screw 25 formed to an inner periphery of the through-hole 24, air mixed into the pressure chamber 20 is discharged to the outside air through a screw gap 27 between the male screw member 26 and female screw 25. A valve element 33 and a valve spring 34 are housed in a valve element storage chamber 29 in the male screw member, so that the valve element 33 opens a valve hole 31 to release pressure in the pressure chamber 20 when the pressure in the pressure chamber 20 becomes large. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a chain tensioner used for maintaining tension of a timing chain that drives a camshaft of an automobile engine.

  In general, an engine of an automobile transmits rotation of a crankshaft to a camshaft through a timing chain (hereinafter referred to as “chain”), and opens and closes a valve of a combustion chamber by the rotation of the camshaft. Here, in order to keep the chain tension within an appropriate range, a tension adjusting device composed of a chain guide provided so as to be able to swing around a fulcrum shaft and a chain tensioner that presses the chain via the chain guide is often used. It is done.

  As a chain tensioner incorporated in this tension adjusting device, a plunger is slidably inserted in a cylindrical cylinder having one end opened and the other end closed, and the plunger is urged in a direction protruding from the cylinder. A return spring is provided, an oil supply passage for introducing hydraulic oil is provided in the pressure chamber surrounded by the plunger and the cylinder, and the operation from the oil supply passage side to the pressure chamber side is performed at the end of the oil supply passage on the pressure chamber side. A valve provided with a check valve that allows only the flow of oil is known (for example, Patent Document 1, FIG. 6).

  When the chain tension increases during engine operation, the chain tensioner moves in the direction in which the plunger is pushed into the cylinder (hereinafter referred to as “push-in direction”) due to the chain tension, and absorbs the chain tension. At this time, the hydraulic oil in the pressure chamber flows out through a leak gap between the sliding surface of the plunger and the cylinder, and a damper action is generated by the viscous resistance of the hydraulic oil, so that the plunger moves slowly.

  On the other hand, when the tension of the chain is reduced during engine operation, the plunger moves in a direction protruding from the cylinder (hereinafter referred to as “protruding direction”) by the urging force of the return spring, and absorbs the slackness of the chain. At this time, the check valve is opened and hydraulic oil flows into the pressure chamber from the oil supply passage, so that the plunger moves quickly.

  In this chain tensioner, air may be mixed into the hydraulic oil supplied from the oil pump to the pressure chamber when the engine is started. In this case, when the chain tension increases, the air mixed in the pressure chamber is compressed. As a result, the plunger moves, so that the damper action of the chain tensioner is reduced.

  In order to prevent the reduction of the damper action, there is known a chain tensioner provided with an air vent passage for discharging air in the pressure chamber (for example, Patent Document 2, FIG. 4).

  In this chain tensioner, a through hole that connects the pressure chamber and the outside air is formed in the cylinder, and a male screw member is screwed into a female screw formed on the inner periphery of the through hole. The air is discharged to the outside through a spiral screw gap formed between the member and the female screw.

  In addition, in order to prevent the chain from becoming over-tensioned when the chain is suddenly tensioned, a relief valve is provided to release the pressure in the pressure chamber when the pressure in the pressure chamber becomes higher than a preset pressure. Chain tensioners are known (see, for example, Patent Document 3).

  This chain tensioner has a through hole that connects the pressure chamber and the outside air at the protruding end of the plunger from the cylinder, and a valve seat is provided at the end of the through hole on the pressure chamber side. A valve body that opens and closes the formed valve hole and a valve spring that biases the valve body in the valve closing direction are accommodated in the through hole. The valve body, the valve spring, and the valve seat constitute a relief valve, and when the pressure in the pressure chamber becomes larger than a preset pressure, the valve body opens the valve hole and the pressure in the pressure chamber To escape.

Japanese Patent Laid-Open No. 10-19095 JP 2002-364720 A Japanese Patent No. 3670911

  By the way, when a relief valve is provided in the chain tensioner having the air vent passage, as shown in Patent Document 3, when the relief valve is incorporated in the protruding end of the plunger from the cylinder, the plunger is equivalent to the length of the relief valve. Need to be formed longer, and the overall length of the chain tensioner becomes longer.

  Therefore, in order to suppress the length of the plunger, it is conceivable to incorporate a relief valve in the cylinder instead of the plunger. However, if a relief valve is incorporated in the cylinder, the cylinder is enlarged by an amount corresponding to the length of the relief valve. It is necessary and the chain tensioner becomes heavy.

  The problem to be solved by the present invention is to provide a small chain tensioner that can release an excessive pressure in the pressure chamber.

  In order to solve the above-described problem, a through-hole that communicates the pressure chamber and the outside air is formed in the cylinder, a male screw member is screwed into a female screw formed on the inner periphery of the through-hole, and the air mixed in the pressure chamber is In a chain tensioner that discharges to the outside air through a helical screw gap formed between a male screw member and a female screw, the male screw member has a hollow structure having a valve body accommodating chamber therein, and the male screw member A valve seat for partitioning the inside and outside of the valve body storage chamber at the end of the pressure chamber side, a valve body for opening and closing a valve hole formed in the valve seat, and a valve spring for biasing the valve body in the valve closing direction Are accommodated in the valve body housing chamber, and when the pressure in the pressure chamber becomes higher than a preset pressure, the valve body opens the valve hole to release the pressure in the pressure chamber.

  In this way, the pressure relief valve body and the valve spring are incorporated in the air vent male screw member, so that the plunger can be lengthened to provide the pressure relief valve body and the valve spring. It is not necessary to increase the size of the cylinder, and it is possible to reduce the size of the chain tensioner.

  The valve seat may be formed integrally with the male screw member. However, if the valve seat is formed separately from the male screw member and the valve seat is press-fitted and fixed to the male screw member, the valve seat can be easily processed. The valve seat can be processed with high accuracy.

  In this case, an air vent groove that communicates the valve body housing chamber and the valve hole can be formed on the contact surface of the valve seat with the valve body. In this way, even if the screw gap is clogged by foreign matter such as a suit or contamination mixed in the hydraulic oil, air can be discharged through the air vent groove, ensuring air discharge performance for a long period of time. Can do.

  It is preferable to form a plurality of air vent grooves at intervals in the circumferential direction. In this way, even when the chain tensioner is used in a posture in which the male screw member is inclined with respect to the vertical direction, stable air bleeding performance can be exhibited regardless of the screwing rotation angle of the male screw member.

  In addition, when the male screw member is provided with a head having a diameter larger than that of the screw shaft portion, and a spring washer having a shape in which a part of the circumference is separated between the head and the cylinder, the spring washer The communication between the screw gap and the outside air can be ensured through the part where a part of the circumference is cut off.

  Further, the male screw member is provided with a head having a diameter larger than that of the screw shaft portion, and teeth having a plurality of radially extending twisted teeth spaced in the circumferential direction between the head and the cylinder. A washer may be incorporated. In this way, since a passage is formed between adjacent teeth of the toothed washer, even if one of the passages is clogged, the communication between the screw gap and the outside air through the other passage. Can be secured and highly reliable.

  If a stopper member that restricts the travel stroke of the valve body is incorporated in the valve body housing chamber, the amount of hydraulic oil flowing out when the valve body opens the valve hole can be suppressed, and excessive pressure drop in the pressure chamber Can be prevented.

  As the stopper member, for example, a flange portion that receives one end of the valve spring and a shaft portion that extends from the flange portion toward the valve body, the valve body is received at the tip of the shaft portion. Things can be adopted.

The present invention can be applied to, for example, the following chain tensioner.
1) The plunger is formed in a bottomed cylindrical shape whose opening end into the cylinder is open, and a screw rod having a male screw on the outer periphery that engages with a female screw formed on the inner periphery of the plunger is provided. The protruding end from the plunger is supported by a rod seat provided in the cylinder, and the male screw and the female screw have a flank angle of the pressure side flank that receives pressure when a load in a direction of pushing the plunger into the cylinder is applied. A sawtooth screw type chain tensioner formed in a sawtooth shape larger than the flank angle of the play side flank.
2) A register ring that elastically tightens the outer periphery of the plunger is accommodated in an accommodation groove formed in the inner periphery of the open end of the cylinder, and the register ring is spaced apart from the outer periphery of the plunger at a certain interval in the axial direction. When the load in the direction in which the plunger protrudes from the cylinder is loaded in each circumferential groove, the diameter of the register ring is expanded to allow the plunger to move. A ring-type chain tensioner provided with a tapered surface and a stopper surface that locks the register ring and restricts movement of the plunger when a load in a direction of pushing the plunger into the cylinder is applied.

  In the chain tensioner of the present invention, the valve body for pressure relief and the valve spring are incorporated in the male screw member for releasing air. Therefore, in order to provide the valve body for pressure relief and the valve spring, the plunger is lengthened. It is not necessary to increase the size of the cylinder, and the chain tensioner can be reduced in size.

The front view which shows the chain transmission apparatus incorporating the chain tensioner of 1st Embodiment of this invention 1 is an enlarged cross-sectional view near the chain tensioner of FIG. Enlarged view of the vicinity of the male screw member in FIG. Enlarged view of the vicinity of the valve seat in FIG. An enlarged view showing an example in which the spring washer shown in FIG. 3 is replaced with a toothed washer. Enlarged perspective view of the toothed washer shown in FIG. The enlarged view which shows the example which incorporated the stopper member in the valve body storage chamber shown in FIG. The expanded sectional view which shows the chain tensioner of 2nd Embodiment of this invention

  FIG. 1 shows a chain transmission device incorporating a chain tensioner 1 according to a first embodiment of the present invention. In this chain transmission device, a sprocket 3 fixed to an engine crankshaft 2 and a sprocket 5 fixed to a camshaft 4 are connected via a chain 6, and the chain 6 rotates the crankshaft 2. This is transmitted to the camshaft 4, and the valve (not shown) of the combustion chamber is opened and closed by the rotation of the camshaft 4.

  The chain 6 is in contact with a chain guide 8 that is swingably supported around the fulcrum shaft 7, and the chain tensioner 1 presses the chain 6 through the chain guide 8.

  As shown in FIG. 2, the chain tensioner 1 includes a cylindrical cylinder 9 that is open at one end and closed at the other end, and a plunger 10 that is slidably inserted in the cylinder 9 in the axial direction. The cylinder 9 is fixed to an engine block (not shown) with bolts 11.

  The plunger 10 is formed in a bottomed cylindrical shape with an insertion end into the cylinder 9 opened, and a female screw 12 is formed on the inner periphery thereof. A screw rod 14 having a male screw 13 that engages with the female screw 12 on the outer periphery is incorporated in the plunger 10. One end of the screw rod 14 protrudes from the plunger 10, and the protruding end is supported by a rod sheet 15 provided in the cylinder 9.

  The male screw 13 and the female screw 12 are formed in a sawtooth shape in which the flank angle of the pressure side flank 16 that receives pressure when a load in the direction of pushing the plunger 10 into the cylinder 9 is applied is larger than the flank angle of the play side flank 17. Has been.

  A return spring 18 is incorporated between the plunger 10 and the screw rod 14. One end of the return spring 18 is supported by the screw rod 14, and the other end presses the plunger 10 via the spring seat 19, and the pressing force urges the plunger 10 in a direction to protrude from the cylinder 9. .

  An oil supply passage 21 communicating with a pressure chamber 20 surrounded by the cylinder 9 and the plunger 10 is formed at the closed end of the cylinder 9. The oil supply passage 21 is connected to an oil supply pump (not shown), and hydraulic oil fed from the oil supply pump is introduced into the pressure chamber 20. A check valve 22 that allows only the flow of hydraulic oil from the oil supply passage 21 side to the pressure chamber 20 side is provided at the end of the oil supply passage 21 on the pressure chamber 20 side.

  A leak gap 23 is formed between the sliding surfaces of the plunger 10 and the cylinder 9, and hydraulic oil in the pressure chamber 20 flows out through the leak gap 23.

  The cylinder 9 is formed with a through hole 24 that communicates the pressure chamber 20 and the outside air.

  As shown in FIG. 3, a female screw 25 is formed on the inner periphery of the through hole 24, and a male screw member 26 is screwed into the female screw 25. The male screw member 26 includes a screw shaft portion 26A having a male screw formed on the outer periphery, and a head portion 26B provided at one end of the screw shaft portion 26A. The head 26B is formed so that its outer periphery is a hexagon, and can be screwed in with a tool such as a spanner.

  A spiral screw gap 27 is formed between the screw shaft portion 26 </ b> A and the female screw 25, and air can pass through the screw gap 27. The head portion 26B is formed with a larger diameter than the screw shaft portion 26A. A spring washer 28 having a shape in which a part of the circumference is cut off is incorporated between the head 26B and the cylinder 9, and a screw gap is provided via a part of the spring washer 28 in which a part of the circumference is cut off. 27 communicates with the outside air.

  The male screw member 26 has a hollow structure having a valve body accommodating chamber 29 therein. A valve seat 30 for partitioning the inside and outside of the valve body housing chamber 29 is provided at the end of the male screw member 26 on the pressure chamber 20 side. The valve seat 30 is formed separately from the male screw member 26, and is press-fitted and fixed in a screw shaft portion 26A formed in a hollow cylindrical shape. The valve seat 30 is formed with a valve hole 31 penetrating the center thereof. An oil passage hole 32 is formed in the head portion 26 </ b> B of the male screw member 26 to communicate between the outside air and the valve body accommodating chamber 29.

  A valve body 33 that opens and closes the valve hole 31 of the valve seat 30 and a valve spring 34 that biases the valve body 33 in the valve closing direction are housed in the valve body housing chamber 29. The valve body 33 is formed in a spherical shape, and opens and closes the valve hole 31 by contacting and separating from the valve seat 30. One end of the valve spring 34 is supported by the inner end surface of the valve body accommodating chamber 29 on the outside air side, and the other end presses the valve body 33. Here, the valve body 33, the valve spring 34, and the valve seat 30 function as a relief valve, and the valve body 33 opens the valve hole 31 when the pressure in the pressure chamber 20 becomes larger than a preset pressure. Thus, the pressure in the pressure chamber 20 is released.

  As shown in FIG. 4, an air vent groove 35 that connects the valve body accommodation chamber 29 and the valve hole 31 is formed on the contact surface of the valve seat 30 with the valve body 33. A plurality of air vent grooves 35 are formed at intervals in the circumferential direction.

  Although the male screw member 26 may be made of a metal, it does not require a strong fastening force, so that a resin can be adopted. On the other hand, the valve seat 30 comes in contact with and separates from the valve body 33. Therefore, if a metal seat is used, its wear resistance can be ensured. Can be prevented.

  Next, an operation example of the chain tensioner 1 will be described.

  When the tension of the chain 6 is reduced during the operation of the engine, the plunger 10 is moved in the protruding direction by the urging force of the return spring 18 to absorb the slack of the chain 6. At this time, since the hydraulic oil supplied from the oil pump flows into the pressure chamber 20 through the oil supply passage 21, the plunger 10 moves quickly.

  On the other hand, when the tension of the chain 6 increases during engine operation, the plunger 10 moves in the pushing direction by the tension of the chain 6 and absorbs the tension of the chain 6. At this time, the screw rod 14 rotates with respect to the plunger 10 while repeating forward and backward movements within the range of the axial clearance between the female screw 12 and the male screw 13 due to the vibration of the chain 6. Further, since the hydraulic oil in the pressure chamber 20 flows out through the leak gap 23 between the sliding surfaces of the plunger 10 and the cylinder 9 and a damper action is generated by the viscous resistance of the hydraulic oil, the plunger 10 moves slowly. To do.

  When the engine is stopped, the tension of the chain 6 may increase depending on the stop position of the camshaft 4. In this case, the chain 6 does not vibrate, so the internal thread 12 of the plunger 10 is received by the external thread 13 of the screw rod 14. Ten positions are fixed. Therefore, when the engine is restarted, the chain 6 is hardly slackened, and the engine can be started smoothly.

  When the engine is stopped, the oil pump is stopped and the hydraulic oil level in the oil supply passage 21 is lowered. Therefore, when the engine is restarted, air may be mixed into the hydraulic oil supplied to the pressure chamber 20 through the oil supply passage 21. In this case, the air mixed in the pressure chamber 20 is a male screw member. 26 and the female screw 25 and the part where a part of the circumference of the spring washer 28 is cut off in order are discharged to the outside air. Therefore, the damper action due to the air in the pressure chamber 20 is unlikely to decrease.

  Since the chain tensioner 1 incorporates the pressure relief valve element 33 and the valve spring 34 inside the male screw member 26 for releasing air, the pressure relief valve element 33 and the valve spring 34 are provided. In addition, it is not necessary to lengthen the plunger 10 or increase the size of the cylinder 9, and the chain tensioner 1 can be reduced in size.

  The valve seat 30 may be formed integrally with the male screw member 26. However, as shown in this embodiment, when the valve seat 30 separate from the male screw member 26 is press-fitted into the screw shaft portion 26A and fixed, The valve seat 30 can be easily processed, and the valve seat 30 can be processed with high accuracy.

  Further, in this chain tensioner 1, since the air vent groove 35 is formed on the contact surface of the valve seat 30 with the valve body 33, the screw gap 27 is clogged by foreign matter such as a suit or contamination mixed in the hydraulic oil. Even in this case, air can be discharged through the air vent groove 35, and stable air discharge performance can be exhibited over a long period of time.

  Although only one air vent groove 35 may be formed, it is preferable to form a plurality of air vent grooves 35 at intervals in the circumferential direction as shown in the above embodiment. In this way, even when the chain tensioner 1 is used in a posture in which the male screw member 26 is inclined with respect to the vertical direction, stable air bleeding performance can be exhibited regardless of the screwing rotation angle of the male screw member 26. .

  In the above embodiment, the spring washer 28 is incorporated between the head 26B of the male screw member 26 and the cylinder. However, as shown in FIGS. 5 and 6, a plurality of radially extending twisted teeth 36a are spaced apart in the circumferential direction. A toothed washer 36 may be incorporated. In this way, since the passages 37 are formed between the adjacent teeth 36a, 36a of the toothed washer 36, even if any one of the passages 37 is clogged, the screw gap is passed through the other passages 37. The communication between the air and the outside air can be ensured, and the reliability is high.

  As shown in FIG. 7, a stopper member 38 that restricts the movement stroke of the valve element 33 may be incorporated in the valve element accommodating chamber 29. The stopper member 38 includes a flange portion 38A that receives one end of the valve spring 34, and a shaft portion 38B that extends from the flange portion 38A toward the valve body 33, and receives the valve body 33 at the tip of the shaft portion 38B. It has become. The shaft portion 38B is formed with a radial hole 39 penetrating the shaft portion 38B in the radial direction and an axial hole 40 intersecting the radial hole 39 and connecting to the oil passage hole 32. The valve body accommodation chamber 29 communicates with the outside air through the radial hole 39 and the axial hole 40.

  As described above, when the stopper member 38 is incorporated in the valve body accommodating chamber 29, the amount of hydraulic oil flowing out when the valve body 33 opens the valve hole 31 can be suppressed, and excessive pressure drop in the pressure chamber 20 is achieved. Can be prevented.

  FIG. 8 shows a chain tensioner 41 according to the second embodiment of the present invention. Portions corresponding to the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  The return spring 18 is incorporated in a pressure chamber 20 surrounded by the cylinder 9 and the plunger 10, one end is supported by the check valve 22, and the other end presses the plunger 10 via the spring seat 19. The plunger 10 is urged in a direction protruding from the cylinder 9 by the pressing.

  A receiving groove 42 extending in the circumferential direction is formed on the inner periphery of the open end of the cylinder 9, and a register ring 43 is received in the receiving groove 42 so as to be movable in the axial direction. A part of the circumference of the register ring 43 is cut off and elastically deformable in the radial direction. The register ring 43 elastically tightens the outer periphery of the plunger 10 and engages with one of a plurality of circumferential grooves 44 formed at regular intervals in the axial direction on the outer periphery of the plunger 10. .

  Within each circumferential groove 44, when a load in the protruding direction is applied to the plunger 10, a taper surface 45 that expands the diameter of the register ring 43 and allows the plunger 10 to move, and a load in the pushing direction of the plunger 10. Is provided with a stopper face 46 that locks the register ring 43 and restricts the movement of the plunger 10 when the chain 6 is loaded. When the tension of the chain 6 increases when the engine is stopped, the circumferential groove 44 is provided. The engagement of the register ring 43 restricts the movement of the plunger 10 in the pushing direction.

  Similar to the first embodiment, the cylinder 9 is formed with a through hole 24 that communicates the pressure chamber 20 and the outside air, and a male screw member 26 for releasing air is screwed into the through hole 24. A pressure relief valve body 33 and a valve spring 34 are incorporated in the male screw member 26.

  As in the first embodiment, the chain tensioner 41 incorporates a pressure relief valve element 33 and a valve spring 34 inside the male screw member 26 for releasing air, so that the pressure relief valve element 33 and It is not necessary to lengthen the plunger 10 or increase the size of the cylinder 9 in order to provide the valve spring 34, and the chain tensioner 41 can be reduced in size.

DESCRIPTION OF SYMBOLS 1 Chain tensioner 9 Cylinder 10 Plunger 12 Female thread 13 Male thread 14 Screw rod 15 Rod seat 16 Pressure side flank 17 Play side flank 18 Return spring 20 Pressure chamber 21 Oil supply passage 22 Check valve 24 Through hole 25 Female thread 26 Male thread member 26A Screw shaft part 26B Head 27 Screw gap 28 Spring washer 29 Valve body accommodating chamber 30 Valve seat 31 Valve hole 33 Valve body 34 Valve spring 35 Air vent groove 36 Toothed washer 36a Tooth 38 Stopper member 38A Flange portion 38B Shaft portion 41 Chain tensioner 42 Housing groove 43 Register ring 44 Circumferential groove 45 Tapered surface 46 Stopper surface

Claims (10)

A plunger (10) is slidably inserted axially into a cylindrical cylinder (9) with one end open and the other end closed, and the plunger (10) is attached in a direction protruding from the cylinder (9). A return spring (18) is provided, an oil supply passage (21) for introducing hydraulic oil is provided in a pressure chamber (20) surrounded by the plunger (10) and the cylinder (9), and the oil supply passage (21 ) Is provided at the end of the pressure chamber (20) side with a check valve (22) that allows only the flow of hydraulic oil from the oil supply passage (21) side to the pressure chamber (20) side. A through hole (24) communicating the pressure chamber (20) and the outside air is formed, and a male screw member (26) is screwed into a female screw (25) formed in the inner periphery of the through hole (24), and the pressure chamber (20 ) The air mixed in the male screw member (26) In the chain tensioner which is adapted to discharge to the outside air through the screw clearance (27) spiral formed between the screw (25),
The male screw member (26) has a hollow structure having a valve body accommodating chamber (29) therein, and the inside and outside of the valve body accommodating chamber (29) are arranged at the end of the male screw member (26) on the pressure chamber (20) side. A valve seat (30) for partitioning, a valve body (33) for opening and closing a valve hole (31) formed in the valve seat (30), and a valve for biasing the valve body (33) in the valve closing direction The spring (34) is accommodated in the valve element accommodating chamber (29), and when the pressure in the pressure chamber (20) becomes larger than a preset pressure, the valve element (33) is ) To release the pressure in the pressure chamber (20).   The chain tensioner according to claim 1, wherein the valve seat (30) is formed separately from the male screw member (26), and the valve seat (30) is press-fitted and fixed to the male screw member (26).   The air vent groove (35) which connects the said valve body storage chamber (29) and a valve hole (31) was formed in the contact surface with the said valve body (33) of the said valve seat (30). 2. The chain tensioner according to 2.   The chain tensioner according to claim 3, wherein a plurality of the air vent grooves (35) are formed at intervals in the circumferential direction.   The male screw member (26) has a head portion (26B) having a diameter larger than that of the screw shaft portion (26A), and a part of the circumference is provided between the head portion (26B) and the cylinder (9). The chain tensioner according to any one of claims 1 to 4, wherein a spring washer (28) having a separated shape is incorporated.   The male screw member (26) has a head portion (26B) having a larger diameter than the screw shaft portion (26A), and a plurality of radially extending portions are provided between the head portion (26B) and the cylinder (9). A chain tensioner according to any of the preceding claims, incorporating a toothed washer (36) having twisted teeth (36a) spaced circumferentially.   The chain tensioner according to any one of claims 1 to 6, wherein a stopper member (38) for restricting a movement stroke of the valve body (33) is incorporated in the valve body accommodating chamber (29).   The stopper member (38) includes a flange portion (38A) for receiving one end of the valve spring (34), and a shaft portion (38B) extending from the flange portion (38A) toward the valve body (33). The chain tensioner according to claim 7, wherein the valve element (33) is received at the tip of the shaft portion (38B).   The plunger (10) is formed in a bottomed cylindrical shape with an opening end into the cylinder (9), and is externally engaged with a female screw (12) formed on the inner periphery of the plunger (10). And a projecting end of the screw rod (14) from the plunger (10) is supported by a rod sheet (15) provided in the cylinder (9), and the male screw ( 13) and the female thread (12) are such that the flank angle of the pressure side flank (16) that receives pressure when a load in the direction of pushing the plunger (10) into the cylinder (9) is applied is the play side flank (17). The chain tensioner according to any one of claims 1 to 8, wherein the chain tensioner is formed in a sawtooth shape larger than the flank angle.   A register ring (43) for elastically fastening the outer periphery of the plunger (10) is accommodated in an accommodation groove (42) formed on the inner periphery of the open end of the cylinder (9), and the register ring (43) is The plunger (10) is engaged with a circumferential groove (44) formed at a constant interval in the axial direction on the outer periphery of the plunger (10), and the plunger (10) is a cylinder in each circumferential groove (44). A taper surface (45) that allows the movement of the plunger (10) by expanding the diameter of the register ring (43) when a load in a direction protruding from (9) is applied; 9) A stopper surface (46) is provided for locking the register ring (43) and restricting the movement of the plunger (10) when a load in the direction of pushing in is applied. Either Mounting of the chain tensioner.

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