JP2010090988A - Chain tensioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a chain tensioner having improved assembling work efficiency on an engine cover. <P>SOLUTION: In the chain tensioner, a bottomed cylindrical cylinder 9 having one end open is inserted into a tensioner mounting hole 12 of the engine cover 11 in the attitude of directing the open end into the engine cover 11 so that a flange 13 formed on the outer periphery of the cylinder 9 abuts on the outer face of the engine cover 11, a plunger 10 is slidably inserted into the cylinder 9 in the axial direction, and a return spring 19 is provided for energizing the plunger 10 to be protruded from the cylinder 9 to thrust a chain 6 with the end of the plunger 10 protruded from the cylinder 9. On the outer periphery of the cylinder 9, a male screw 21 and a cylindrical face 22 are formed so that the cylindrical face 22 is located on the open end side of the cylinder 9. On the inner periphery of the tensioner mounting hole 12, a female screw 23 and a cylindrical face 24 are formed which engages with the male screw 21 on the outer periphery of the cylinder 9 and which is suitable for the cylindrical face 22 on the outer periphery of the cylinder 9, respectively. <P>COPYRIGHT: (C)2010,JPO&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, 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 bottomed cylindrical cylinder with one open end is inserted into the engine cover tensioner mounting hole with the opening end facing the inside of the engine cover and formed on the outer periphery of the cylinder. An oil supply passage for contacting the outer surface of the engine cover with the outer surface of the engine cover, inserting a plunger into the cylinder so as to be slidable in the axial direction, and introducing hydraulic oil from the outside of the cylinder into a pressure chamber surrounded by the cylinder and the plunger A check valve for preventing backflow of hydraulic oil in the oil supply passage, a return spring for urging the plunger in a direction protruding from the cylinder, and a chain being pressed by the protruding end of the plunger from the cylinder What was made into is known (patent document 1).

  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 the leak gap between the sliding surface of the plunger and the cylinder, the flow rate of the hydraulic oil is limited, and a damper action is generated, 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, since the hydraulic oil supplied from the oil pump flows into the pressure chamber through the oil supply passage, the plunger moves quickly.
JP 2006-153118 A

  By the way, the chain tensioner has a plurality of bolt holes formed in the outer peripheral flange of the cylinder. When the chain tensioner is assembled to the engine cover, the cylinder is inserted into the tensioner mounting hole of the engine cover and The flange is brought into contact with the outer surface of the engine cover, the bolt is inserted into each bolt hole of the flange, screwed into the tapped hole of the engine cover, and the flange is fixed by tightening each bolt.

  However, it is troublesome to prepare a plurality of bolts, and it is also troublesome to screw the bolts so that they are not obliquely tightened.

  The problem to be solved by the present invention is to provide a chain tensioner that is excellent in assembling workability to the engine cover.

  In order to solve the above-described problems, a male screw and a cylindrical surface are formed on the outer periphery of the cylinder so that the cylindrical surface is positioned on the opening end side of the cylinder, and an inner periphery of the tensioner mounting hole A female screw that is screw-engaged with the male screw and a cylindrical surface that is fitted to the outer cylindrical surface of the cylinder are formed. In this way, the chain tensioner can be assembled by screwing the external thread on the outer periphery of the cylinder into the internal thread on the inner periphery of the tensioner mounting hole without using a bolt. In addition, the cylinder surface on the outer periphery of the cylinder is fitted to the cylinder surface on the inner periphery of the tensioner mounting hole, and the center of the cylinder and the tensioner mounting hole is aligned by the fitting. When screwing into the peripheral female screw, the male screw can be prevented from being obliquely screwed in, and smooth screwing is possible.

  If the outer periphery of the flange is a hexagonal shape, a wrench can be applied to the outer periphery of the flange, so that the male screw on the outer periphery of the cylinder can be tightened to the female screw on the inner periphery of the tensioner mounting hole by operating the wrench. . The same is true if a two-chamfered portion is formed on the outer periphery of the flange. In addition, even if a tool engagement groove is formed on the bottom end surface of the cylinder, a tool (such as a flat-blade screwdriver) engaged with the tool engagement groove is operated so that a male screw on the outer periphery of the cylinder is attached to a tensioner mounting hole. It is possible to fasten to the inner peripheral female screw. This is the same even if an insertion hole for a hexagon stick wrench is formed on the end face on the bottom side of the cylinder.

  When an annular seal member is incorporated between the flange and the engine cover, a plurality of straight portions are formed at intervals in the circumferential direction on the inner periphery of the seal member, and the straight portions are tightened on the outer periphery of the cylinder. When fitted, the seal member can be prevented from falling off from the chain tensioner in a state before being assembled to the engine cover, and the workability of assembling to the engine cover is improved.

  Similarly, when an annular seal member is incorporated between the flange and the engine cover, a rubber lip continuous in the circumferential direction is provided on the inner periphery of the seal member, and the lip is fitted to the outer periphery of the cylinder with an allowance. Even if they are combined, it is possible to prevent the seal member from falling off from the chain tensioner in a state before being assembled to the engine cover, and the workability of assembling to the engine cover is improved.

  It is preferable that a circumferential groove is formed on the outer periphery of the portion inserted into the tensioner mounting hole of the cylinder, and an inlet of the oil supply passage is opened in the circumferential groove. In this way, even when the position of the cylinder with respect to the tensioner mounting hole is shifted in the circumferential direction, the hydraulic oil can be reliably introduced into the oil supply passage.

  Similarly, a large-diameter portion that is opposed to the cylindrical surface of the outer periphery of the cylinder at a radial interval is provided on the inner periphery of the tensioner mounting hole, and is formed between the large-diameter portion and the outer periphery of the cylinder. An inlet of the oil supply passage may be opened in the annular space. Even if it does in this way, also when the position of the cylinder with respect to a tensioner attachment hole has shifted | deviated to the circumferential direction, hydraulic fluid can be reliably introduce | transduced into an oil supply channel | path.

  Further, when an identification mark indicating the position of the oil supply passage is attached to the end face on the bottom side of the cylinder, the operation of screwing the male screw on the outer periphery of the cylinder into the internal screw on the inner periphery of the tensioner mounting hole is confirmed. Can be done.

  In addition, a set groove having a step is formed on the inner periphery of the cylinder so that the opening end side of the cylinder has a smaller diameter than the bottom side of the cylinder, and a part of the circumference is cut off in the set groove The set ring is incorporated in an elastically reduced diameter state, and an engagement groove that engages the inner diameter side portion of the set ring is formed on the outer periphery of the plunger, and the plunger is connected to the cylinder by the engagement of the set ring and the engagement groove. It can be held in a state of being pushed in, and the set ring can be expanded in the set groove by releasing the plunger further into the cylinder, and the engagement with the engagement groove can be released.

The present invention can be applied to the following chain tensioner, for example.
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 sheet 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 force 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 for elastically tightening the outer periphery of the plunger is accommodated in an accommodation groove formed on the inner periphery of the cylinder, and the register ring is formed on the outer periphery of the plunger at a constant interval in the axial direction. A tapered surface that engages with a circumferential groove and allows the movement of the plunger by expanding the diameter of the register ring when the plunger is pressed in a direction protruding from the cylinder in each circumferential groove, and the plunger A ring-type chain tensioner provided with a stopper surface that locks the register ring and restricts the movement of the plunger when it is pushed in the direction of pushing it into the cylinder.

  The chain tensioner of the present invention can be assembled to the engine cover by screwing the male screw on the outer periphery of the cylinder into the female screw on the inner periphery of the tensioner mounting hole. Excellent. In addition, the cylinder surface on the outer periphery of the cylinder is fitted to the cylinder surface on the inner periphery of the tensioner mounting hole, and the center of the cylinder and the tensioner mounting hole is aligned by the fitting. When screwing into the peripheral female screw, the male screw can be prevented from being obliquely screwed in, and smooth screwing is possible.

  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 the crankshaft 2 of the engine and a sprocket 5 fixed to the 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 has a bottomed cylindrical cylinder 9 with one end opened, and a plunger 10 inserted into the cylinder 9 so as to be slidable in the axial direction. The cylinder 9 is inserted into the tensioner mounting hole 12 of the engine cover 11 with the opening end facing the engine cover 11. A flange 13 is integrally formed on the outer periphery of the cylinder 9, and the flange 13 is in contact with the outer surface of the engine cover 11 via an annular seal member 14.

  The plunger 10 is formed in a bottomed cylindrical shape whose opening end into the cylinder 9 is opened, and a female screw 15 is formed on the inner periphery thereof. A screw rod 17 having a male screw 16 that engages with the female screw 15 on the outer periphery is incorporated in the plunger 10. One end of the screw rod 17 protrudes from the plunger 10, and the protruding end is supported by a rod sheet 18 provided in the cylinder 9.

  A return spring 19 is incorporated between the plunger 10 and the screw rod 17. One end of the return spring 19 is supported by the screw rod 17, and the other end presses the plunger 10 via the spring seat 20, and the plunger 10 is urged in a direction protruding from the cylinder 9 by the pressing. . The plunger 10 has a protruding end from the cylinder 9 abutting on the chain guide 8 and presses the chain 6 via the chain guide 8.

  The male screw 16 and the female screw 15 are formed in a sawtooth shape in which the flank angle of the pressure side flank that receives pressure when a force 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. .

  In the cylinder 9, a male screw 21 and a cylindrical surface 22 are formed on the outer periphery of the portion inserted into the tensioner mounting hole 12. The cylindrical surface 22 is positioned closer to the opening end of the cylinder 9 than the male screw 21 and has a smaller diameter than the male screw 21. On the other hand, on the inner periphery of the tensioner mounting hole 12, an internal thread 23 that engages with an external thread 21 on the outer periphery of the cylinder 9 and a cylindrical surface 22 on the outer periphery of the cylinder 9 in order from the outer surface side to the inner surface side of the engine cover 11. And a cylindrical surface 24 to be fitted to the inner surface.

  The cylinder 9 is formed with an oil supply passage 26 for introducing hydraulic oil into a pressure chamber 25 surrounded by the cylinder 9 and the plunger 10. The oil supply passage 26 penetrates the cylinder 9 in the radial direction, and the inlet of the oil supply passage 26 opens into a circumferential groove 27 formed on the outer periphery of the portion inserted into the tensioner mounting hole 12 of the cylinder 9. .

  The circumferential groove 27 communicates with an oil hole 28 formed in the engine cover 11, and hydraulic oil supplied from an oil pump (not shown) through the oil hole 28 is supplied to the circumferential groove 27 and the oil supply. The pressure chamber 25 is introduced through the passage 26 in order. A check valve 29 is provided at the outlet of the oil supply passage 26 to prevent the backflow of hydraulic oil from the pressure chamber 25 to the oil supply passage 26.

  On the inner periphery of the cylinder 9, a set groove 30 is formed with a step so that the opening end side of the cylinder 9 has a smaller diameter than the bottom side of the cylinder 9. A set ring 31 is incorporated in the set groove 30. Yes. The set ring 31 has a shape in which a part of the circumference is cut off, and is elastically reduced in diameter.

  As shown in FIG. 3, an engagement groove 32 that matches the set groove 30 is formed on the outer periphery of the plunger 10 when the plunger 10 is pushed into the cylinder 9. In the state where the set ring 31 is on the opening end side of the cylinder 9 in the set groove 30, the inner diameter side portion of the set ring 31 is engaged with the engagement groove 32, and the plunger 10 is pushed into the cylinder 9 by the engagement. The state is maintained (hereinafter referred to as “initial set”). Further, the set ring 31 moves in the set groove 30 from the open end side of the cylinder 9 to the bottom side by pushing the plunger 10 further into the cylinder 9, expands the diameter in the set groove 30, and engages the engagement groove 32. Release the engagement.

  A receiving groove 33 is formed on the inner periphery of the cylinder 9 on the bottom side of the cylinder 9 with respect to the set groove 30, and a stopper ring 34 received in the receiving groove 33 elastically tightens the outer periphery of the plunger 10. ing. On the other hand, a stopper groove 35 is formed on the outer periphery of the plunger 10 on the insertion end side of the plunger 10 into the cylinder 9 with respect to the engagement groove 32, and when the plunger 10 protrudes from the cylinder 9, the stopper ring 34. Engages with the stopper groove 35 to prevent the plunger 10 from coming off from the cylinder 9.

  As shown in FIG. 2, the seal member 14 is incorporated between the flange 13 and the engine cover 11, and hydraulic oil supplied from the oil supply passage 26 passes through a screw gap between the male screw 21 and the female screw 23. Leaking outside the engine cover 11 is prevented. As shown in FIG. 4, the seal member 14 has a plurality of linear portions 36 formed on the inner periphery thereof at intervals in the circumferential direction, and the linear portions 36 are fitted to the outer periphery of the cylinder 9 with a tightening margin. As shown in FIG. 3, the seal member 14 is held on the outer periphery of the cylinder 9 when the chain tensioner 1 is not assembled to the engine cover 11.

  As shown in FIG. 6, the outer periphery of the flange 13 has a hexagonal shape, and a wrench (such as a spanner or a box wrench) can be applied to the outer periphery of the flange 13.

  For example, the chain tensioner 1 is assembled to the engine cover 11 as follows.

  First, as shown in FIG. 3, the chain tensioner 1 is initially set, and in this state, the cylinder 9 is inserted into the tensioner mounting hole 12 of the engine cover 11, and the cylindrical surface 22 on the outer periphery of the cylinder 9 is inserted into the tensioner mounting hole 12. It is made to fit in the cylindrical surface 24 of a circumference. At this time, the centers of the cylinder 9 and the tensioner mounting hole 12 coincide with each other by fitting the cylindrical surfaces 22 and 24 together.

  Subsequently, the male screw 21 on the outer periphery of the cylinder 9 is screwed into the female screw 23 on the inner periphery of the tensioner mounting hole 12. At this time, a wrench can be applied to the outer periphery of the flange 13, and the male screw 21 can be fastened to the female screw 23 by operating the wrench. When the male screw 21 is completely screwed into the female screw 23, the plunger 10 is pushed into the cylinder 9 by the reaction force received from the chain guide 8, so that the set ring 31 opens in the set groove 30 as shown in FIG. Moving from the end side to the bottom side, the initial setting of the chain tensioner 1 is released.

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

  When the tension of the chain 6 becomes smaller during the operation of the engine, the plunger 10 moves in the protruding direction by the urging force of the return spring 19 and absorbs the slack of the chain 6. At this time, since the hydraulic oil supplied from the oil pump flows into the pressure chamber 25 through the oil supply passage 26, 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 hydraulic oil in the pressure chamber 25 flows out through the leak gap between the sliding surface of the plunger 10 and the cylinder 9, and a damper action is generated, so that the plunger 10 moves slowly. Further, the screw rod 17 is rotated with respect to the plunger 10 while being repeatedly advanced and retracted within the gap between the female screw 15 and the male screw 16 due to the vibration of the chain 6.

  When the engine is stopped, the tension of the chain 6 may increase depending on the stop position of a cam (not shown) connected to the camshaft 4. In this case, the chain 6 does not vibrate, so the female screw 15 of the plunger 10 is screwed into the screw rod. The plunger 10 is received by 17 male screws 16 and the position of the plunger 10 is fixed. Therefore, when the engine is restarted, the chain 6 is hardly slackened, and the engine can be started smoothly.

  The chain tensioner 1 can be assembled to the engine cover 11 by screwing the male screw 21 on the outer periphery of the cylinder 9 into the female screw 23 on the inner periphery of the tensioner mounting hole 12, so that no bolt is required for the assembly. Excellent assembly workability.

  Further, when the chain tensioner 1 is assembled to the engine cover 11, the cylindrical surface 22 on the outer periphery of the cylinder 9 is fitted into the cylindrical surface 24 on the inner periphery of the tensioner mounting hole 12, and the cylinder 9 and the tensioner mounting hole are thereby fitted. Since the centers of 12 coincide with each other, when the male screw 21 on the outer periphery of the cylinder 9 is screwed into the female screw 23 on the inner periphery of the tensioner mounting hole 12, the male screw 21 can be prevented from being obliquely screwed in, and smooth screwing can be achieved. Is possible.

  Further, since the linear portion 36 of the inner periphery of the seal member 14 is fitted to the outer periphery of the cylinder 9 with a tightening margin, the chain tensioner 1 is connected to the seal member from the chain tensioner 1 before being assembled to the engine cover 11. 14 can be prevented from falling off, and the assembling workability to the engine cover 11 is excellent.

  Further, the chain tensioner 1 is connected to the oil hole 28 via the circumferential groove 27 even when the position of the cylinder 9 with respect to the tensioner mounting hole 12 is shifted in the circumferential direction and the oil hole 28 and the oil supply passage 26 do not match. Since the communication between the oil supply passages 26 is ensured, the hydraulic oil can be reliably introduced into the oil supply passages 26.

  As shown in FIG. 5, a seal member 38 provided with a rubber lip 37 continuous in the circumferential direction is used as a seal member incorporated between the flange 13 and the engine cover 11. You may make it fit to the outer periphery of this with the allowance. Even in this case, it is possible to prevent the seal member 38 from dropping from the chain tensioner 1 in a state before being assembled to the engine cover 11.

  The outer periphery of the flange 13 may form a double chamfered portion 39 as shown in FIG. Even in this case, since the wrench can be applied to the outer periphery of the flange 13, it is possible to operate the wrench to fasten the male screw 21 on the outer periphery of the cylinder 9 to the female screw 23 on the inner periphery of the tensioner mounting hole 12. Become. Here, the two-chamfered portion 39 is a portion having a shape obtained by cutting the outer periphery of the flange 13 along two planes parallel to the plane including the center of the cylinder 9.

  Further, as shown in FIGS. 8A and 8B, a tool engagement groove 40 may be formed on the end surface on the bottom side of the cylinder 9. Even in this case, it is possible to tighten the male screw 21 on the outer periphery of the cylinder 9 to the female screw 23 on the inner periphery of the tensioner mounting hole 12 by operating a tool (such as a flat-blade screwdriver) engaged with the tool engaging groove 40. It becomes. Similarly, as shown in FIGS. 9A and 9B, a hexagon wrench insertion hole 41 may be formed on the end surface of the cylinder 9 on the bottom side.

  Further, as shown in FIGS. 8A and 8B, an identification mark 42 indicating the position of the oil supply passage 26 can be attached to the end face on the bottom side of the cylinder 9. In this way, the operation of screwing the male screw 21 on the outer periphery of the cylinder 9 into the female screw 23 on the inner periphery of the tensioner mounting hole 12 can be performed while confirming the position of the oil supply passage 26.

  As shown in FIG. 10, a large-diameter portion 43 is provided on the inner periphery of the tensioner mounting hole 12 so as to face the cylindrical surface 22 on the outer periphery of the cylinder 9 with a gap in the radial direction. The inlet of the oil supply passage 26 may be opened in an annular space 44 formed between the outer periphery of the oil supply passage 26 and the outer periphery. Even in this case, even when the position of the cylinder 9 with respect to the tensioner mounting hole 12 is shifted in the circumferential direction and the oil hole 28 and the oil supply passage 26 do not match, the oil hole 28 and the oil supply passage 26 are interposed via the annular space 44. Therefore, the hydraulic oil can be reliably introduced into the oil supply passage 26.

  FIG. 11 shows a chain tensioner 51 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.

  An accommodation groove 53 for accommodating the register ring 52 is formed on the inner periphery of the cylinder 9, and the register ring 52 accommodated in the accommodation groove 53 elastically tightens the outer periphery of the plunger 10. A plurality of circumferential grooves 54 are formed on the outer periphery of the plunger 10 at regular intervals in the axial direction, and the register ring 52 is engaged with the circumferential grooves 54.

  In each circumferential groove 54, when the plunger 10 is pressed in the direction protruding from the cylinder 9, the register ring 52 is enlarged to allow the plunger 10 to move, and the plunger 10 is moved into the cylinder 9. Is provided with a stopper surface 56 that locks the register ring 52 and restricts the movement of the plunger 10 when the chain 6 is pushed in the direction in which the chain 6 is tensioned. The engagement between the groove 54 and the register ring 52 restricts the movement of the plunger 10 in the pushing direction.

  A relief valve 57 that opens when the pressure in the pressure chamber 25 becomes larger than a preset pressure is incorporated at the protruding end of the plunger 10 from the cylinder 9, and the tension of the chain 6 suddenly increases. Sometimes, the relief valve 57 is opened to release the hydraulic oil in the pressure chamber 25, so that the tension of the chain 6 is relieved.

  Similarly to the first embodiment, the chain tensioner 51 can be assembled to the engine cover 11 by screwing the male screw 21 on the outer periphery of the cylinder 9 into the female screw 23 on the inner periphery of the tensioner mounting hole 12. It is not necessary and is excellent in assembling workability to the engine cover 11.

  Further, when the chain tensioner 51 is assembled to the engine cover 11, the cylindrical surface 22 on the outer periphery of the cylinder 9 is fitted into the cylindrical surface 24 on the inner periphery of the tensioner mounting hole 12, and the cylinder 9 and the tensioner mounting hole are thereby fitted. Since the centers of 12 coincide with each other, when the male screw 21 on the outer periphery of the cylinder 9 is screwed into the female screw 23 on the inner periphery of the tensioner mounting hole 12, the male screw 21 can be prevented from being obliquely screwed in, and smooth screwing can be achieved. Is possible.

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. FIG. 2 is an enlarged sectional view showing a state before the chain tensioner shown in FIG. 2 is assembled to the engine cover. Sectional view along line IV-IV in FIG. The figure which shows the modification of the sealing member shown in FIG. Side view of chain tensioner shown in FIG. The figure which shows the modification of the flange shown in FIG. (A) is a side view of a chain tensioner showing another modification of the flange shown in FIG. 6, (b) is a front view of (a). (A) is a side view of a chain tensioner showing still another modification of the flange shown in FIG. 6, (b) is a front view of (a). The figure which shows the modification of the tensioner attachment hole shown in FIG. The expanded sectional view which shows the chain tensioner of 2nd Embodiment of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Chain tensioner 6 Chain 9 Cylinder 10 Plunger 11 Engine cover 12 Tensioner attachment hole 13 Flange 14 Seal member 15 Female screw 16 Male screw 17 Screw rod 18 Rod seat 19 Return spring 21 Male screw 22 Cylindrical surface 23 Female screw 24 Cylindrical surface 25 Pressure chamber 26 Oil supply passage 27 Circumferential groove 29 Check valve 30 Set groove 31 Set ring 32 Engagement groove 36 Linear portion 37 Lip 38 Seal member 39 Two chamfered portion 40 Tool engagement groove 41 Hexagon wrench insertion hole 42 Identification mark 43 Large diameter portion 44 Annular Space 51 Chain tensioner 52 Register ring 53 Housing groove 54 Circumferential groove 55 Tapered surface 56 Stopper surface

Claims (13)

The bottomed cylindrical cylinder (9) with one end opened is inserted into the tensioner mounting hole (12) of the engine cover (11) with the opening end facing into the engine cover (11), and the cylinder (9) The flange (13) formed on the outer periphery is brought into contact with the outer surface of the engine cover (11), and the plunger (10) is slidably inserted in the cylinder (9) in the axial direction. A check valve for providing an oil supply passage (26) for introducing hydraulic oil from the outside of the cylinder (9) to the pressure chamber (25) surrounded by the plunger (10) and preventing backflow of the hydraulic oil in the oil supply passage (26) (29) is provided, a return spring (19) is provided to urge the plunger (10) in a direction protruding from the cylinder (9), and a tip of the plunger (10) protrudes from the cylinder (9). In chain tensioner for pressing the over emissions (6),
A male screw (21) and a cylindrical surface (22) are formed on the outer periphery of the cylinder (9) so that the cylindrical surface (22) is located on the opening end side of the cylinder (9), and the tensioner mounting hole (12) On the inner periphery of the cylinder (9), the internal thread (23) that engages with the external thread (21) on the outer periphery of the cylinder (9), and the cylindrical surface (24) that engages with the external cylindrical surface (22) of the cylinder (9). A chain tensioner characterized by forming   The chain tensioner according to claim 1, wherein the outer periphery of the flange (13) has a hexagonal shape.   The chain tensioner according to claim 1, wherein a double chamfered portion (39) is formed on an outer periphery of the flange (13).   The chain tensioner according to claim 1, wherein a tool engaging groove (40) is formed in an end face on a bottom side of the cylinder (9).   The chain tensioner according to claim 1, wherein an insertion hole (41) for a hexagon stick wrench is formed in an end face of the bottom side of the cylinder (9).   An annular seal member (14) is incorporated between the flange (13) and the engine cover (11), and a plurality of linear portions (36) are formed at intervals in the circumferential direction on the inner periphery of the seal member (14). The chain tensioner according to any one of claims 1 to 5, wherein the straight portion (36) is fitted to the outer periphery of the cylinder (9) with a tightening margin.   An annular sealing member (38) is assembled between the flange (13) and the engine cover (11), and a circumferentially continuous rubber lip (37) is provided on the inner periphery of the sealing member (38). The chain tensioner according to any one of claims 1 to 5, wherein a lip (37) is fitted to an outer periphery of the cylinder (9) with a tightening margin.   A circumferential groove (27) is formed on the outer periphery of the insertion portion of the cylinder (9) into the tensioner mounting hole (12), and the inlet of the oil supply passage (26) is opened in the circumferential groove (27). The chain tensioner according to any one of claims 1 to 7.   A large-diameter portion (43) facing the cylindrical surface (22) of the outer periphery of the cylinder (9) at a radial interval is provided on the inner periphery of the tensioner mounting hole (12), and the large-diameter portion (43 The chain tensioner according to any one of claims 1 to 7, wherein an inlet of the oil supply passage (26) is opened in an annular space (44) formed between the cylinder (9) and an outer periphery of the cylinder (9).   The chain tensioner according to any one of claims 1 to 9, wherein an identification mark (42) indicating a position of the oil supply passage (26) is attached to an end surface of the bottom side of the cylinder (9).   On the inner periphery of the cylinder (9), a set groove (30) having a step is formed so that the opening end side of the cylinder (9) has a smaller diameter than the bottom side of the cylinder (9), and the set groove (30 ), A set ring (31) having a shape obtained by cutting off a part of the circumference is incorporated in an elastically reduced diameter state, and an engagement groove (32) engaged with an inner diameter side portion of the set ring (31). Is formed on the outer periphery of the plunger (10), and the plunger (10) can be held in a state of being pushed into the cylinder (9) by the engagement of the set ring (31) and the engagement groove (32). The ring of the set ring (31) is expanded in the set groove (30) by pushing the cylinder (9) further into the cylinder (9) to release the engagement with the engagement groove (32). The chain tensioner according to any of the above.   The plunger (10) is formed into a bottomed cylindrical shape whose opening end into the cylinder (9) is open, and a male screw (16) that engages with a female screw (15) formed on the inner periphery of the plunger (10). And a projecting end of the screw rod (17) from the plunger (10) is supported by a rod sheet (18) provided in the cylinder (9), and the male screw ( 16) and the internal thread (15) are saw teeth in which the flank angle of the pressure flank that receives pressure when a force in the direction of pushing the plunger (10) into the cylinder (9) is applied is larger than the flank angle of the play flank The chain tensioner according to any one of claims 1 to 11, wherein the chain tensioner is formed in a shape.   A register ring (52) for elastically tightening the outer periphery of the plunger (10) is accommodated in an accommodation groove (53) formed in the inner periphery of the cylinder (9), and the register ring (52) is accommodated in the plunger (10). ) Are engaged with circumferential grooves (54) formed at regular intervals in the axial direction, and in each circumferential groove (54), the plunger (10) is moved from the cylinder (9). When pressed in the protruding direction, the diameter of the register ring (52) is expanded to allow the plunger (10) to move, and the plunger (10) is pushed into the cylinder (9). The chain tensioner according to any one of claims 1 to 11, further comprising a stopper surface (56) for locking the register ring (52) and restricting the movement of the plunger (10) when pressed.

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