JP2007333095A - Chain tenitioner mounting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a chain tensioner mounting device, wherein an externally mounting type chain tensioner can be miniaturized and lightened in weight, and relieved hydraulic oil can be returned to an engine compartment. <P>SOLUTION: In this chain tensioner mounting device, a flange 12 is formed on the periphery of a housing 11 inserted in the tensioner mounting hole (a) of an engine cover A, and a plunger 15 and a return spring 16 are assembled in the cylinder chamber 14 of the housing 11. A male screw 19 on the periphery of a screw rod 18 is engaged with a sawtooth-shaped female screw 17 on the inner periphery of the opening end part of the plunger 15. An oil feeding passage 26 and a check valve 27 are provided in the housing 11. A valve mounting hole 37 and a pressure relief hole 38 are formed in the flange 12. An oil passage 50 to lead hydraulic oil leaked to the pressure relief hole 38 into the engine cover A is formed on the surface of the flange 12 on which the engine cover A abuts and the periphery of the housing 11. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention mainly relates to an attachment device for a chain tensioner that keeps the tension of a timing chain for driving a camshaft constant.

  As a chain tensioner used for tension adjustment of a timing chain, what was described in patent document 1 is conventionally known.

  In the above chain tensioner, a cylindrical chain pressing plunger whose front end is closed and a return spring that presses the plunger outward are incorporated in a cylinder chamber formed in the housing, and the rear end of the plunger A serrated female screw is provided on the inner periphery of the part, and a serrated male screw formed on the outer periphery of the screw rod is thread-engaged with the female screw, and the screw rod and plunger are urged in a direction of extension by a spring, and the housing Is provided with an oil supply passage communicating with the pressure chamber formed on the back of the plunger, a check valve is incorporated in the oil outlet of the oil supply passage, and hydraulic oil supplied from the oil supply passage to the pressure chamber through the check valve The pushing force applied to the plunger is buffered.

  There are two types of chain tensioners with the above configuration: an interior type in which the mounting piece formed on the outer periphery of the housing is bolted to the engine block, and an exterior type that is attached to the engine cover. In the chain tensioner, a flange is provided on the outer periphery of the end of the housing, the housing is inserted into the tensioner mounting hole formed in the engine cover from the outside of the engine cover, and the flange that is abutted against the outer surface of the engine cover is attached to the bolt. It is fixed by tightening.

  In order to prevent the chain from becoming over-tensioned, the exterior type chain tensioner as described above incorporates a relief valve. When the hydraulic oil pressure in the pressure chamber exceeds the set pressure of the relief valve, the relief valve There is one in which the valve is opened to release the pressure in the pressure chamber to the outside.

JP 10-1332039 A

  By the way, in an exterior type chain tensioner having a relief valve, when the relief valve is assembled in the flange, the hydraulic oil in the pressure chamber leaks to the outside of the engine when the relief valve is opened. It is designed to be installed at a position offset to the side.

  For this reason, in an exterior type chain tensioner having a conventional relief valve, the outer diameter of the housing is increased, the weight is increased, and the size is increased.

  An object of the present invention is to reduce the size and weight of an exterior type chain tensioner having a relief valve, and to return hydraulic oil leaked by opening the relief valve into the engine room. Is to provide a mounting device.

  In order to solve the above-described problems, in the present invention, a flange that is abutted against the outer surface of the engine cover and bolted to the outer periphery of the housing that is inserted into the tensioner mounting hole of the engine cover is provided. A cylinder chamber that opens at the end face located in the engine cover is formed, and a cylindrical chain pressing plunger that closes the front end and opens the rear end, and presses the plunger outward. A return spring is incorporated, and a serrated female screw is provided on the inner periphery of the rear end of the plunger, and a serrated male screw formed on the outer periphery of the screw rod is thread-engaged with the female screw. The housing is energized in the direction of extension, and the housing is provided with an oil supply passage communicating with a pressure chamber formed on the back of the plunger. In the chain tensioner mounting device, the check valve is incorporated in the oil outlet of the oil supply passage, and the pushing force applied to the plunger by the hydraulic oil supplied from the check valve to the pressure chamber is buffered. The flange is provided with a valve mounting hole that communicates with the pressure chamber from the outer periphery thereof, and a pressure relief hole that communicates with the valve mounting hole from the abutting surface with respect to the engine cover, and the pressure in the pressure chamber is within the valve mounting hole. A relief valve that opens when the set pressure is exceeded and connects the pressure chamber side inlet of the valve mounting hole and the pressure relief hole is built in, and the relief valve is screwed into the valve mounting hole from the outer periphery of the flange. The flange is fixed by tightening the tightening screw. Than is the working fluid that has leaked into the pressure relief hole adopts the configuration of forming the oil passage leading to the engine cover to the surface.

  Here, by applying a seal adhesive to the outer periphery of the tightening screw, the screw gap between the valve mounting hole and the screw engaging portion of the tightening screw can be sealed. Oil can be prevented from leaking.

  Further, by incorporating a gasket between the abutting surfaces of the flange and the engine cover, it is possible to prevent the hydraulic oil from leaking to the outside from between the abutting surfaces of the flange and the engine cover.

  As described above, a valve mounting hole is formed in the flange, and the relief valve is assembled in the valve mounting hole, so that the outer diameter of the housing does not increase, and a small and lightweight chain with a relief valve is provided. A tensioner can be obtained.

  Further, a pressure relief hole communicating with the valve mounting hole is formed on the abutting surface of the flange against the engine cover, and the pressure relief hole and the inside of the engine cover are formed on the abutting surface of the flange against the engine cover and the outer peripheral surface of the housing. By communicating with the oil passage, the hydraulic oil leaked from the pressure chamber to the pressure relief hole can be returned to the engine room by opening the relief valve, and leakage of the hydraulic oil to the outside of the engine room can be prevented. .

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a chain tension adjusting device using a chain tensioner according to the present invention. As shown in the figure, a chain 5 is spanned between a sprocket 2 attached to the end of the crankshaft 1 and a sprocket 4 attached to the end of the camshaft 3, and a chain guide 6 is connected to the slack side chain 5 a of the chain 5. Are in contact.

  The chain guide 6 is supported so as to be swingable about a shaft 7 provided at the lower end thereof. On one side of the chain guide 6, there is provided a chain tensioner 10 that presses and presses the chain guide 6 against the chain 5 to keep the tension of the chain 5 constant.

  The chain tensioner 10 has a cylindrical housing 11 that is inserted into a tensioner mounting hole a formed in the engine cover A from the outside of the engine cover A. A flange 12 is formed that abuts the surface. The flange 12 is fixed to the engine cover A by tightening bolts 13.

  As shown in FIG. 2, the housing 11 is formed with a cylinder chamber 14 that opens at an end surface located inside the engine cover A. The plunger 15 is formed in the cylinder chamber 14, and the plunger 15 protrudes outward. A return spring 16 for imparting a sex is incorporated.

  The plunger 15 has a cylindrical shape in which the front end located outside the cylinder chamber 14 is closed and the rear end is open, and is provided on the outer periphery of the screw rod 18 on the female screw 17 formed on the inner periphery of the open end. The male screw 19 is engaged with the screw.

  The screw rod 18 is formed with a through hole 20 extending in the axial direction. The through hole 20 is a stepped hole having a small diameter at the rear end, and between the step 20a on the inner periphery of the through hole 20 and the closed end of the plunger 15, a spring seat 21 having a spherical tip, and a spring 22 And the plunger 15 and the screw rod 18 are urged in the extending direction by the spring 22.

  The internal thread 17 of the inner periphery of the plunger 15 and the external thread 19 of the outer periphery of the screw rod 18 are serrated with the flank angle of the pressure side flank 23 receiving the axial pushing force applied to the plunger 15 larger than the flank angle of the play side flank 24. The sawtooth screw is provided with a lead angle that moves in a direction in which the plunger 15 and the screw rod 18 are rotated while being relatively rotated by the pressing of the spring 22.

  The housing 11 is formed with an oil supply passage 26 communicating with a pressure chamber 25 formed on the back portion of the plunger 15, and a check valve 27 is provided at an oil outlet portion of the oil supply passage 26 on the pressure chamber 25 side.

  The check valve 27 includes a valve seat 29 press-fitted into a stepped hole 28 provided at the closed end of the cylinder chamber 14, a valve body 31 that opens and closes a valve hole 30 formed in the valve seat 29, and the valve The retainer 32 restricts the opening / closing amount of the body 31. When the pressure in the pressure chamber 25 becomes higher than the supply pressure of the hydraulic oil supplied to the oil supply passage 26, the valve body 31 closes the valve hole 30. ing.

  Here, the valve seat 29 also has a function as a rod seat for receiving the rear end of the screw rod 18, and the contact surface between the valve seat 29 and the screw rod 18 is a tapered surface 29a.

  A ring groove 33 is formed on the inner periphery of the opening end of the housing 11, and a small-diameter groove 34 is formed on the front side of the ring groove 33. An elastically deformable set ring 35 is incorporated in the small diameter groove 34 in a reduced diameter state, and the inner peripheral portion of the set ring 35 engages with a set groove 36 formed on the outer periphery of the distal end portion of the plunger 15. The plunger 15 is held in the pushed state by the engagement.

  In the chain tensioner, the tip end of the housing 11 is inserted into the tensioner mounting hole a of the engine cover A and the flange 12 is bolted to the engine cover A with the plunger 15 held in the pushed state.

  When the engine is driven with the chain tensioner attached as described above, the slack side chain 5 a is tensioned and a pushing force is applied to the plunger 15 via the chain guide 6. When the plunger 15 is retracted by the load of the pushing force and the set ring 35 faces the ring groove 33, the diameter of the set ring 35 is expanded and the engagement with the set groove 36 is released. As shown in FIG. 4, the chain guide 6 is pressed and tension is applied to the chain 5.

  As shown in FIG. 4, the flange 12 is formed with a valve mounting hole 37 that communicates with the pressure chamber 25 from the upper periphery and a pressure relief hole 38 that communicates with the valve mounting hole 37 from the abutting surface with respect to the engine cover A. Has been.

  As shown in FIG. 5, the valve mounting hole 37 is a stepped hole whose end on the pressure chamber 25 side has a small diameter, and the relief valve 40 is incorporated in the large diameter hole of the valve mounting hole 37.

  The relief valve 40 includes a valve sleeve 41 in which a valve hole 42 is formed at the lower closed end, a spherical valve body 43 incorporated in the valve sleeve 41, and a biasing of the valve body 43 toward the valve hole 42. And a tightening screw 45 for closing the upper end opening of the valve sleeve 41. The tightening screw 45 is engaged with a female screw 39 formed on the inner periphery of the upper end of the valve mounting hole 37, and the tightening screw The relief valve 40 is fixed by tightening 45.

  Here, the valve sleeve 41 is formed with a radial through hole 46 communicating with the inside of the valve sleeve 41 through the pressure relief hole 38. The tightening screw 45 has a fitting shaft portion 45a that is press-fitted into the upper end opening of the valve sleeve 41 at the lower end, and a restriction shaft portion 45b that restricts the opening / closing amount of the valve body 43 at the lower end of the fitting shaft portion 45a. Is formed.

  As shown in FIGS. 4 and 5, a recess 47 is formed on the abutting surface of the flange 12 with respect to the engine cover A to guide the hydraulic oil leaked into the pressure relief hole 38 to the outer periphery of the housing 11. On the other hand, a flat surface 48 is provided on the outer periphery of the housing 11, and the flat surface 48 forms a passage 49 with the inner diameter surface of the tensioner mounting hole a, and the passage 49 and the recess 47 leak into the pressure relief hole 38. An oil passage 50 is formed to guide the hydraulic oil that has been discharged into the engine cover A.

  As shown in FIG. 6, a seal adhesive 51 is applied between the screw engaging portions of the tightening screw 45 and the female screw 39, and the seal adhesive 51 prevents the hydraulic oil from leaking from the screw engaging portion to the outside. is doing. Further, as shown in FIG. 5, a gasket 52 is incorporated between the abutting surfaces of the flange 12 and the engine cover A to prevent the hydraulic oil from leaking from between the abutting surfaces.

  The chain tension adjusting device shown in the embodiment has the above structure, and when the engine is driven, the chain 5 moves in the direction indicated by the arrow in FIG. 1 and the camshaft 3 is driven. Further, engine oil (hydraulic oil) is sent into the pressure chamber 25 of the chain tensioner 10 by driving a pump (not shown).

  When the camshaft 3 is driven and the slack side chain 5a of the chain 5 is slack due to torque fluctuation, the plunger 15 and the screw rod 18 are moved outward by the pressure of the hydraulic oil supplied from the oil supply passage 26 to the pressure chamber 25. The screw rod 18 moves away from the valve seat 29, and the hydraulic oil flows into the pressure chamber 25 and the through hole 20 of the screw rod 18.

  The plunger 15 presses the chain guide 6 by the outward movement of the plunger 15, so that the slack of the chain 5 is absorbed, and the screw 22 is rotated by the spring 22 to rotate toward the check valve 27. The chain 5 is held at a predetermined tension by moving to contact the valve seat 29 and stopping the plunger 15 and the screw rod 18.

  On the other hand, when the chain 5 is tensioned, a pushing force is applied to the plunger 15 via the chain 5 and the chain guide 6. At this time, since the pressure of the hydraulic oil flowing into the through hole 20 of the screw rod 18 and the plunger 15 and the pressure in the pressure chamber 25 are increased, the check valve 27 closes the oil supply passage 26 and the inside of the housing 11. The pushing force is received by the hydraulic oil sealed in and the pressure side flank 23 of the female screw 17 and the male screw 19, and the plunger 15 does not move backward.

  When the pressing force that presses the plunger 15 is stronger than the elastic force of the return spring 16, the screw rod 18 rotates and the plunger 15 moves in a direction in which the volume of the pressure chamber 25 decreases.

  At this time, the hydraulic oil in the pressure chamber 25 leaks to the outside through a minute gap formed between the sliding surfaces of the cylinder chamber 14 and the plunger 15, and the plunger 15 has the elastic force of the return spring 16 and the pushing force. Slowly move back to the position where it balances.

  When the chain 5 vibrates, the plunger 15 repeatedly advances and retreats within the screw gap formed in the screw engaging portion of the female screw 17 and the male screw 19, and the hydraulic damper action is caused by the hydraulic oil sealed in the pressure chamber 25. The vibration is absorbed by.

  Further, when the plunger 15 is suddenly pushed, the pressure in the pressure chamber 25 rapidly increases. When the pressure exceeds the set pressure of the relief valve 40, the valve body 43 of the relief valve 40 opens the valve hole 42. The hydraulic oil in the pressure chamber 25 opens and flows from the valve hole 43 into the valve sleeve 41 and flows from the through hole 46 and the pressure relief hole 38 to the oil passage 50 as shown by arrows in FIGS. Return to the engine cover A.

  Therefore, the pressure in the pressure chamber 25 does not become abnormally high, and the chain 5 does not become over tension. Further, since the hydraulic oil is returned into the engine cover A as described above, it is possible to prevent the outside of the engine from being contaminated by the hydraulic oil.

  As shown in the embodiment, by forming the valve mounting hole 37 in the flange 12 and incorporating the relief valve 40 in the valve mounting hole 37, the outer diameter of the housing 11 does not increase, A small and lightweight chain tensioner with a relief valve can be obtained.

Schematic of a chain tension adjusting device using a chain tensioner mounting device according to the present invention. Longitudinal front view showing an initial set state of the chain tensioner shown in FIG. Right side view of FIG. Longitudinal front view showing the chain tension adjustment state of the chain tensioner shown in FIG. Sectional view of the relief valve assembly Enlarged cross-sectional view of the tightening screw

Explanation of symbols

A Engine cover a Tensioner mounting hole 11 Housing 12 Flange 13 Bolt 14 Cylinder chamber 15 Plunger 16 Return spring 17 Female thread 18 Screw rod 19 Male thread 22 Spring 25 Pressure chamber 26 Oil supply passage 27 Check valve 37 Valve mounting hole 38 Pressure relief hole 40 Relief valve 45 Clamping screw 50 Oil passage 51 Seal adhesive 52 Gasket

Claims (3)

A flange that is abutted against the outer surface of the engine cover and bolted to the outer periphery of the housing that is inserted into the tensioner mounting hole of the engine cover is provided, and a cylinder chamber that opens at the end face located in the engine cover is formed in the housing In the cylinder chamber, a cylindrical chain pressing plunger whose front end is closed and the rear end is opened, and a return spring that presses the plunger outward are incorporated, and the inner end of the rear end of the plunger Is provided with a serrated female screw, and a male serrated male screw formed on the outer periphery of the screw rod is screw-engaged with the female screw, and the screw rod and plunger are urged in a direction of extension by a spring. An oil supply passage communicating with the pressure chamber formed at the back of the plunger is provided, and a check valve is provided at the oil outlet of the oil supply passage Embedded in the mounting apparatus of the chain tensioner which is adapted to buffer the pushing force exerted on the plunger by hydraulic oil supplied from the check valve in the pressure chamber,
The flange is provided with a valve mounting hole that communicates with the pressure chamber from the outer periphery thereof, and a pressure relief hole that communicates with the valve mounting hole from an abutting surface with respect to the engine cover. A relief valve is built in that opens when the pressure exceeds the set pressure and connects the pressure chamber side inlet of the valve mounting hole and the pressure relief hole. The relief valve is screwed into the valve mounting hole from the outer periphery of the flange. The chain tensioner is fixed by tightening a tightening screw, and an oil passage is formed on the abutting surface of the flange against the engine cover and on the outer peripheral surface of the housing to guide the working oil leaked into the pressure relief hole into the engine cover. Mounting equipment.   The chain tensioner mounting device according to claim 1, wherein a seal adhesive is applied to an outer periphery of the tightening screw.   The chain tensioner mounting device according to claim 1 or 2, wherein a gasket is incorporated between the abutting surfaces of the flange and the engine cover.

Images