JP4474329B2 - Tensioner lifter - Google Patents

Description

  The present invention provides a tensioner body, a plunger that is slidably fitted to the tensioner body, and a spring force that urges one end of the plunger to protrude from the tensioner body. And a tensioner lifter that applies tension to the endless transmission band.

A wedge member is disposed between the tensioner body, which is slidably fitted to the tensioner body so that one end protrudes from the tensioner body, and the force in the direction to push back the plunger is endless. For example, Patent Document 1 discloses a tensioner lifter that suppresses the return of the plunger by being locked by a wedge member when acting from the transmission band side.
JP-A-6-193695

  However, in the tensioner lifter disclosed in Patent Document 1, the return of the plunger is locked by the wedge member, and it is difficult to attenuate the tension of the endless transmission band.

  The present invention has been made in view of such circumstances. In the non-operating state of the endless transmission band, the return of the plunger is regulated to apply tension to the endless transmission band, and in the operating state of the endless transmission band, the endless transmission band An object of the present invention is to provide a tensioner lifter that can reduce the tension.

In order to achieve the above object, the invention according to claim 1 is directed to a tensioner body, a plunger slidably fitted to the tensioner body, and an urging force so that one end of the plunger protrudes from the tensioner body. A tensioner lifter that exerts a spring force that exerts a spring force between the tensioner body and the plunger and applies tension to the endless transmission band, and is capable of communicating with an oil passage provided in the tensioner body in the tensioner body A chamber is formed facing the other end of the plunger, and an inclined portion that is inclined away from the outer peripheral surface of the plunger toward the biasing direction of the plunger by the spring is formed on the tensioner body on the outer side of the plunger. Provided in surface contact with the inclined portion and the outer peripheral surface of the plunger. Wedge member capable of locking the movement is disposed between the front Symbol tensioner body and the plunger, slidably to and the other end is abutted at one end to the wedge member to the tensioner body so as to face to the hydraulic chamber The plunger is fitted to a cylindrical sleeve to be fitted so as to be relatively slidable, and the wedge member can receive the hydraulic pressure of the hydraulic chamber via the sleeve to be unlocked. you.

According to the present invention, in the operation state of the endless transmission band, by applying the hydraulic pressure to the hydraulic chamber, the wedge member is pushed back to the position where the locked state is released, so that the wedge member does not act on the sliding of the plunger. The tension of the endless transmission band can be attenuated by pressure adjustment by hydraulic pressure and damping force of hydraulic pressure. In addition, when the hydraulic pressure is released from the hydraulic chamber when the endless transmission band is not in operation, the return of the plunger due to the tension of the endless transmission band can be locked by the wedge member. It is possible to always apply tension to the.

In particular , since the hydraulic pressure acting on the wedge member can be adjusted by changing the pressure receiving area facing the hydraulic chamber of the sleeve, the timing of unlocking by the wedge member and the friction value by the wedge member can be adjusted without changing the inclination angle of the tapered hole. Each can be set.

  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 sectional view of an essential part of an internal combustion engine showing a part of a timing transmission mechanism. FIG. 2 is a longitudinal section of a tensioner lifter when the engine is stopped. FIG. 3 is a sectional view taken along line 3-3 in FIG. 2, and FIG. 4 is a longitudinal sectional view of the tensioner lifter in the engine operating state.

  First, in FIG. 1, a camshaft 7 is rotatably supported on a cylinder head 6 coupled to a cylinder block 5 of an internal combustion engine. The camshaft 7 has a cam chain 9 which is an endless transmission band. Rotational power from a crankshaft (not shown) is transmitted by a timing transmission mechanism 10 at a reduction ratio of 1/2, and the cam chain 9 is wound around a driven sprocket 11 provided on the camshaft 7.

  A tensioner slipper 14 whose one end is pivotally supported by the cylinder block 5 is in contact with the outer periphery of the relaxation side of the cam chain 9, and a tensioner lifter 15 that generates a pressing force pressing the tensioner slipper 14 against the cam chain 9. It is fixed to the cylinder head 6 so as to press the pressure receiving protrusion 14a provided near the other end of the tension slipper 14.

  In FIG. 2, the tensioner lifter 15 is slidably fitted to the tensioner body 18 so that one end of the tensioner body 18 is fixed to the cylinder head 6 and the pressure receiving protrusion 14 a of the tensioner slipper 14 is in contact with the tensioner body 18. A plunger 19, a spring 20 provided between the tensioner body 18 and the plunger 19 by exerting a spring force that urges one end of the plunger 19 to protrude from the tensioner body 18, and an axial movement of the plunger 19 A wedge member 21 disposed between the tensioner body 18 and the plunger 19 so as to be locked, and a cylinder that is slidably fitted to the tensioner body 18 and is fitted to the plunger 19 so as to be slidable relative to each other. Shaped sleeve 22.

  The tensioner body 18 is formed by first and second bodies 16 and 17 being fastened to each other, and a first sliding hole having one end opened to the tension slipper 14 side at the center of the first body 16. 24, a tapered hole 25 as an inclined portion that is inclined outwardly from the outer peripheral surface of the plunger 19 as it goes in the biasing direction of the plunger 19 by the spring 20, and a tapered hole 25. The second sliding hole 26 having a larger diameter than the small-diameter end is provided coaxially in order from the tension slipper 14 side, and between the other end of the first sliding hole 24 and the large-diameter end of the tapered hole 25. An annular first step portion 27 facing away from the tension slipper 14 is formed, and between the small diameter end of the taper hole 25 and one end of the second sliding hole 26 facing away from the tension slipper 14. The second step portion 28 of the annular is formed.

  As shown in FIG. 1, a mounting hole 29 is provided in the cylinder head 6, and the first body 16 inserted through the mounting hole 29 is fastened to the cylinder head 6 by a plurality of bolts 30. The second body 17 has a fitting closing portion 17a that is fitted to the other end side of the second sliding hole 26 and closes the other end of the second sliding hole 26, and includes a plurality of bolts 31. Thus, the first body 16 is fastened.

  The plunger 19 is press-fitted into the plunger main body 32 with a cylindrical plunger main body 32 slidably fitted into the first sliding hole 24 and a part of the plunger 19 fitted to one end of the plunger main body 32. The tip member 33 is in contact with the pressure receiving protrusion 14 a of the tension slipper 14. Thus, a hydraulic chamber 35 is formed in the tensioner body 18 so as to face the other end of the plunger 19, and the coiled spring 20 includes a fitting closing portion 17 a of the second body 17, The plunger 19 is contracted between the distal end member 33 of the plunger 19.

  A cylindrical portion 17b that extends coaxially within the second sliding hole 26 so as to be surrounded by the spring 20 is integrally connected to the fitting closing portion 17a of the second body 17, and this cylindrical portion 17b. A check valve 36 is disposed therein. The check valve 36 is a cylindrical spring receiving member 38 that is fitted and fixed to the cylindrical portion 17 b so as to form a valve chamber 37 between the check valve 36 and the cylindrical portion 17 b. A valve seat 39 provided in the portion 17b, a spherical valve body 40 accommodated in the valve chamber 37 so as to be seatable on the valve seat 39, and a biasing direction in which the valve body 40 is seated on the valve seat 39. And a valve spring 41 that is contracted between the valve body 40 and the spring receiving member 38, and the cylindrical portion 17 b is provided with a valve hole 42 that opens in the center of the valve seat 39 coaxially. The cylindrical portion 17b is provided with a plurality of communication holes 43 that allow the valve chamber 37 to communicate with the hydraulic chamber 35, and the spring receiving member 38 is also provided with a communication hole 44 that allows the valve chamber 37 to communicate with the hydraulic chamber 35 coaxially. .

  An annular oil passage 45 is formed between the outer periphery of the fitting closed portion 17a and the inner periphery of the second sliding hole 26, and a plurality of oil passages 46 that allow the oil passage 45 to communicate with the valve hole 42. Is provided in the fitting closed portion 17a, and an oil passage 48 is provided in the second body 17 for connecting an oil passage 47 (see FIG. 1) provided in the cylinder head 6 to the oil passage 46 through a hydraulic source (not shown). It is done. That is, the hydraulic pressure source is connected to the hydraulic chamber 35 via the oil passages 48, 45, 46... And the check valve 36.

  In addition, a pair of annular seal members 49 and 50 sandwiching the annular oil passage 45 from both sides are mounted on the outer periphery of the fitting blocking portion 17a, and these seal members 49 and 50 are provided in the second sliding hole. The inner surface of 26 is elastically contacted.

  A relief valve 52 is disposed on the distal end member 33 of the plunger 19, and the relief valve 52 has an end wall 53 a facing the hydraulic chamber 35 at one end and the distal end member 33 from the inner side. A cylindrical valve housing 53 to be fitted and fixed, a valve body 55 supported on the valve housing 53 so as to be able to be seated on a valve seat 54 provided on the end wall 53a, and the valve body 55 are connected to the valve seat. And a relief spring 56 that exerts a spring force to be seated on 54.

  A valve hole 57 communicating with the hydraulic chamber 35 is provided in the end wall 53 a of the valve housing 53 so as to open at the center of the valve seat 54. Further, the valve body 55 has a tapered seal portion 55 a into which a part is inserted into the valve hole 57, and the seal portion 55 a can be seated on the valve seat 54. The valve body 55 is integrally provided with a cylindrical guide cylinder 58 that is inserted into the valve housing 53 so as to be movable in the axial direction, and the relief spring 56 is contracted between the tip member 33 and the guide cylinder 58. Is done.

  Further, the distal end member 33 is provided with an external communication hole 59 that allows the inside of the valve housing 53 to communicate with the outside. When a hydraulic pressure that exceeds the pressure determined by the relief spring 56 acts on the valve body 55 from the hydraulic chamber 35, The body 55 is separated from the valve seat 54 to open the valve hole 57, and a part of the hydraulic pressure in the hydraulic chamber 35 passes through the passage 60 provided in the valve body 55 and the guide cylinder 58 from the external communication hole 59. Released in.

  An air vent valve 61 is disposed in the first body 16 so as to be positioned above the hydraulic chamber 35 in the attached state to the cylinder head 6. The air vent valve 61 includes first and second valve seat members 63 and 64 which are fitted and fixed to the first body 16 in a state of being in contact with each other so as to form a valve chamber 62 therebetween. A spherical shape that is accommodated in the valve chamber 62 so as to be alternatively seated on the first and second valve seats 65 and 66 provided on the first and second valve seat members 63 and 64, respectively, facing the valve chamber 62. A first valve seat member, comprising: a valve body 67; and a valve spring 68 provided between the valve body 67 and the second valve member 64 by exerting a spring force to seat the valve body 67 on the first valve seat 65. 63 and the first body 16 are provided with an inflow passage 69 having one end communicating with the hydraulic chamber 35 and the other end opened to the central portion of the first valve seat 65, and the second valve seat member 64 and the first body 16. One end of the body 16 is opened at the center of the second valve seat 66 and the other end Discharge passage 70 which is open in the internal combustion engine is provided.

  The set load of the valve spring 68 is such that the valve body 67 is separated from the first valve seat 65 when the hydraulic pressure acts on the hydraulic chamber 35 and the pressure of the air pushed out from the hydraulic chamber 35 acts on the valve body 67. The valve body 67 is set to be seated on the second valve seat 66 when the hydraulic pressure in the hydraulic chamber 35 higher than the air pressure is applied to the valve body 67. In other words, the air vent valve 61 discharges the air in the hydraulic chamber 35 into the internal combustion engine, while preventing the air from entering the hydraulic chamber 35 from the internal combustion engine and discharging the pressure oil in the hydraulic chamber 35 to the outside. It serves to prevent emissions.

  Referring also to FIG. 3, the inner peripheral surface of the tapered hole 25 provided in the first body 16 of the tensioner body 18 so that the hydraulic chamber 35 side has a small diameter and coaxially surrounds the plunger 19, and the plunger 19. Are arranged between the first body 16 and the plunger 19 of the tensioner body 18 at, for example, three positions spaced in the circumferential direction of the plunger 19. When the plunger 19 returns to the hydraulic chamber 35 side, the wedge members 21 are driven by the plunger 19 by frictional contact with the outer peripheral surface of the plunger 19, and friction is applied to the inner peripheral surface of the tapered hole 25 and the outer peripheral surface of the plunger 19. Contact and lock the movement of the plunger 19 in the axial direction.

  Moreover, between the first step portion 27 of the first body 16 and each of the wedge members 21..., For example, two superposed sheets are used so that each wedge member 21. Disc springs 71 and 71 are interposed.

  Each of the wedge members 21 is moved to the side that receives the hydraulic pressure of the hydraulic chamber 35 and releases the locked state, that is, the side that compresses the disc springs 71. The wedge members 21 are moved in the first body 16 of the tensioner body 18. 2 One end of a cylindrical sleeve 22 that fits slidably into the sliding hole 26 and fits an enlarged diameter portion 32a provided at the other end of the plunger main body 32 in the plunger 19 is slidable. The other end of the sleeve 22 is disposed so as to face the hydraulic chamber 35. That is, the hydraulic chamber 35 is formed in the tensioner body 18 between the plunger 19 and the sleeve 22 and the fitting closed portion 17a of the second body 17, and faces the sleeve 22 of the fitting closed portion 17a. A plurality of radial grooves 72 are provided on the surface to prevent the entire other end of the sleeve 22 from coming into close contact with the fitting block portion 17a.

  Next, the operation of this embodiment will be described. An oil provided in the tensioner body 18 is slidably fitted in a plunger 19 having one end abutted against the pressure receiving projection 14a of the tension slipper 14. A hydraulic chamber 35 communicating with the passages 48, 45, 46... Via the check valve 36 is formed so as to face the other end of the plunger 19, and as the plunger 19 is biased by the spring 20, A tapered hole 25 inclined so as to move away from the outer peripheral surface is provided in the first body 16 of the tensioner body 18 so as to coaxially surround the plunger 19, and comes into surface contact with the inner peripheral surface of the tapered hole 25 and the outer peripheral surface of the plunger 19. For example, three wedge members 21 that can lock the 19 axial movement receive the hydraulic pressure of the hydraulic chamber 35 and are locked. It is disposed between the tensioner body 18 and the plunger 19 so as to removal.

  Therefore, in a state where the cam chain 9 travels while the engine is operating, as shown in FIG. 4, each wedge member 21... Resists the spring force of the disc spring 71. Thus, the wedge member 21 does not act on the sliding movement of the plunger 19, and the tension of the cam chain 9 can be attenuated by the hydraulic pressure adjustment and the hydraulic damping force. .

  Further, in the state where the hydraulic pressure is released from the hydraulic chamber 35 with the cam chain 9 stopped with the engine stopped, the return of the plunger 19 due to the tension of the cam chain 9 is locked by the wedge members 21 as shown in FIG. Therefore, the return of the plunger 19 can be restricted, and a tension can always be applied to the cam chain 9.

  In addition, the plunger 19 is attached to a cylindrical sleeve 22 that is slidably fitted to the first body 16 of the tensioner body 18 with one end abutting against each wedge member 21 and the other end facing the hydraulic chamber 35. Since the hydraulic pressure acting on the wedge members 21 is adjusted by changing the pressure receiving area facing the hydraulic chamber 35 of the sleeve 22 without changing the inclination angle of the taper hole 25, The timing of unlocking by the wedge members 21... And the friction value by the wedge members 21.

  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.

  For example, in the above-described embodiment, the taper hole 25 is used as an inclined portion provided in the tensioner body 18 on the outer side of the plunger 19 by inclining away from the outer peripheral surface of the plunger 19 in the biasing direction of the plunger 19 by the spring 20. However, the tensioner body 18 may be provided with inclined grooves as inclined portions at a plurality of locations spaced in the circumferential direction of the plunger 19.

It is a principal part longitudinal cross-sectional view of the internal combustion engine which shows a part of timing adjustment transmission mechanism. It is a longitudinal cross-sectional view of the tensioner lifter when the engine is stopped. FIG. 3 is a sectional view taken along line 3-3 in FIG. 2. It is a longitudinal cross-sectional view of a tensioner lifter in an engine operating state.

9... Cam chain 15 that is an endless transmission band... Tensioner lifter 18... Tensioner body 19. Plunger 20... Spring 21. Taper hole 35 as a part ... Hydraulic chambers 45, 46, 48 ... Oil passage

Claims (1)

A tensioner body (18), a plunger (19) slidably fitted to the tensioner body (18), and an end of the plunger (19) are urged so as to protrude from the tensioner body (18). A tensioner lifter that exerts a spring force and includes a spring (20) provided between the tensioner body (18) and the plunger (19), and applies tension to the endless transmission band (9).
In the tensioner body (18), a hydraulic chamber (35) that can communicate with an oil passage (45, 46, 48) provided in the tensioner body (18) is formed facing the other end of the plunger (19). An inclined portion (25) inclined so as to move away from the outer peripheral surface of the plunger (19) as it goes in the biasing direction of the plunger (19) by the spring (20) is formed on the tensioner on the outer side of the plunger (19). provided in the body (18), said inclined portion (25) and a wedge member which can lock the axial movement of the surface contact with the plunger to the outer peripheral surface (19) of said plunger (19) (21), before Symbol tensioner body (18) and said arranged between the plunger (19), prior to the and the other end is abutted at one end to the wedge member (21) to face the said hydraulic chamber (35) The plunger (19) is slidably fitted to a cylindrical sleeve (22) slidably fitted to the tensioner body (18), and the wedge member (21) is fitted to the sleeve (22). Tenshonarifu data, characterized in that it is possible to unlock state by receiving the hydraulic pressure of the hydraulic chamber (35) through.

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