JP2006266311A - Hydraulic auto tensioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydraulic auto tensioner for holding the tensile force of a belt adequate during driving an engine by stabilizing the start of the engine during driving the engine with a motor generator. <P>SOLUTION: In the auto tensioner, a piston 20 is inserted into a sleeve 17 in a cylinder 11 to form a pressure chamber 21. An outer cylinder portion 28c of a rod support on the upper part of a rod 19 is inserted into the cylinder 11, and a return spring 30 is incorporated into a first reservoir chamber 29 inside the rod support 28. A second reservoir chamber 33 is formed in a bellows 32 between the rod 19 and the cylinder 11. A check valve 35 is provided in a first passage 34 between the pressure chamber 21 and the first reservoir chamber 29. Operating oil in the pressure chamber 21 damps the force of the belt on the cylinder 11 to hold the tensile force of the belt constant. A throttle 41 and a solenoid on-off valve 42 are provided in a second passage 40 between the pressure chamber 21 and the second reservoir chamber 33. The solenoid on-off valve 42 closes the second passage 40 during driving the engine with the motor generator to prevent contraction, Thus, the belt is held in the condition of excessive tensile force. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a hydraulic auto tensioner that maintains a constant tension of an accessory driving belt such as a compressor or water pump of an air conditioner.

  A motor / generator is installed. During normal driving, the motor / generator is switched to a power generation operation, the drive wheels are rotated by driving the engine, and auxiliary devices such as the motor / generator and the compressor of the air conditioner are driven. When the vehicle is stopped, the engine is stopped and the motor / generator is switched to the starting operation to drive the auxiliary machine. In an idle stop-compatible vehicle, when the engine is restarted after the idle stop, the motor / generator The engine is driven by.

  FIG. 8 and FIG. 9 show an outline of a belt transmission device that drives an auxiliary machine of an idle stop-compatible vehicle. FIG. 8 shows that the engine 5 and the auxiliary machine 7 are driven by the motor / generator 6 switched to the starting operation. Indicates the state. FIG. 9 shows a state where the motor / generator 6 and the auxiliary machine 7 switched to the power generation operation by the engine 5 are driven.

  In the belt drive device for driving auxiliary equipment as described above, the tension pulley 3 is brought into contact with the slack side of the belt 4 when the engine 5 is driven, and the swingable pulley arm 1 supporting the tension pulley 3 is connected to the auto tensioner A. Thus, the tension of the belt 4 is kept constant.

As said auto tensioner A, what was described in patent document 1 is known. In this hydraulic auto tensioner, the tension change of the belt 4 is absorbed by a return spring provided outside the cylinder and a hydraulic damper provided inside the cylinder.
Japanese Patent Laid-Open No. 10-184825

  By the way, in the hydraulic auto tensioner described in Patent Document 1, when employed in the belt transmission device shown in FIGS. 8 and 9, the belt load increases rapidly when the engine 5 is driven by the motor / generator 6. Therefore, excessive belt tension acts on the hydraulic auto tensioner A. At this time, hydraulic oil in the hydraulic damper provided in the cylinder of the hydraulic auto tensioner leaks and the hydraulic auto tensioner contracts until the belt tension is stabilized, and the belt slips due to the change in the position of the tension pulley, There is a possibility that the engine cannot be started stably.

  In order to eliminate the inconveniences described above, the amount of leakage of hydraulic fluid in the hydraulic damper of the hydraulic auto tensioner is reduced to increase the damping performance so that the tension pulley 3 does not displace due to the excessive tension of the belt 4. However, during normal running by driving the engine 5, there is a problem that the responsiveness to the tension fluctuation due to the load of the auxiliary machine 7 is deteriorated and the belt 4 becomes over-tensioned.

  An object of the present invention is to enable a stable engine start by fixing a tension pulley at a fixed position when an engine is driven by a motor / generator, so that a belt can be held at an appropriate tension during normal running by driving the engine. Is to provide a hydraulic auto tensioner.

  In order to solve the above problems, in the present invention, a cylinder having a closed end, a bottomed sleeve having a lower end fitted in a sleeve fitting hole formed in an inner bottom surface of the cylinder, A rod having a piston slidable in the sleeve at the lower end, a pressure chamber formed in the sleeve by the piston, a spring seat fixed to the upper end of the rod located outside the cylinder, and the spring seat An inner cylinder portion fixed to the rod is provided on the inner periphery of the end plate that abuts the lower surface of the end plate, and the lower end portion of the outer cylinder portion formed on the outer periphery of the end plate is slidably fitted into the cylinder. And a rod support that forms a first reservoir chamber with the rod, and one end connected to the upper outer periphery of the cylinder and the other end connected to the spring seat and Two reservoir chambers are formed A retractable bellows, and a return spring that biases the cylinder and rod in a direction in which the cylinder and rod extend, and a pressure chamber and a first reservoir chamber are provided between the sliding surfaces of the sleeve and the piston. A first passage is provided, and a check valve is provided in the first passage to close the first passage when the pressure in the pressure chamber becomes higher than the pressure in the first reservoir chamber. A second passage that communicates with the second reservoir chamber, and a throttle portion and an electromagnetic on-off valve that closes the second passage by energizing the actuator are provided in the second passage, and the outer cylindrical portion of the rod support and the cylinder A configuration is adopted in which a third passage for communicating the first reservoir chamber and the second reservoir chamber is provided between the sliding surfaces.

  Here, as a check valve, an orifice plate which is attached to the lower end portion of the rod to form a ring groove between the lower surfaces of the piston and has an oil passage hole communicating the ring groove and the pressure chamber, and the ring groove A seal ring that closes the piston and closes the first passage when the pressure in the pressure chamber becomes higher than the pressure in the first reservoir chamber is adopted. can do.

  Further, as the electromagnetic open / close valve, a valve sleeve having a valve hole formed at the closed end, a valve body for opening / closing the valve hole of the valve sleeve, and an actuator for opening / closing the valve body can be employed. .

  The actuator may be a direct acting solenoid or a linear motor.

  In the hydraulic auto tensioner according to the present invention, when a retaining ring for restricting the relative extension of the cylinder and the rod support is attached to the inner periphery of the opening end of the cylinder, the hydraulic auto tensioner is assembled to the actual vehicle. It is possible to prevent the rod support and rod of the hydraulic auto tensioner from coming out of the cylinder at the stage of transportation before installation.

  In the hydraulic autotensioner having the above-described configuration, when the second passage is closed by the electromagnetic opening / closing valve, the hydraulic oil in the pressure chamber can be prevented from flowing from the passage to the second reservoir chamber. The cylinder and the rod can be prevented from moving relative to each other in the contracting direction by the oil, and the tension pulley to which the adjustment force of the hydraulic auto tensioner is applied can be fixed at a fixed position.

  For this reason, by fixing the tension pulley when the engine is driven by the motor / generator, the belt is kept in a tensioned state, preventing the belt from slipping and enabling stable engine start.

  Further, when the electromagnetic on-off valve is opened during normal driving by driving the engine, the hydraulic oil can flow between the pressure chamber and the first reservoir chamber and the second reservoir chamber. When the hydraulic oil flows into the second reservoir chamber, the hydraulic oil is throttled by the throttle portion, and the pressure in the pressure chamber increases. At this time, since the check valve closes the first passage, the hydraulic damper effect is generated by the hydraulic oil in the pressure chamber. For this reason, a change in belt tension due to the load of the auxiliary machine can be absorbed by the hydraulic auto tensioner, and the belt tension can be maintained at an appropriate tension. As a result, it is possible to suppress a reduction in the life of the belt and to prevent the generation of abnormal noise due to belt flapping.

  Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the pulley arm 1 is supported so as to be swingable about a fulcrum shaft 2, and a tension pulley 3 is rotatably supported at one end thereof. A hydraulic auto tensioner 10 is connected to the other end of the pulley arm 1, and the hydraulic auto tensioner 10 biases the pulley arm 1 in a direction in which the tension pulley 3 presses the belt 4.

  Here, the belt 4 is driven by the engine 5 shown in FIG. 8 during normal running, and is driven by the motor / generator 6 when the vehicle is stopped, and the tension pulley is connected to the slack side belt of the belt 4 driven by the engine 5. 3 is pressed.

  As shown in FIG. 2, the hydraulic auto tensioner 10 has a cylinder 11 made of an aluminum alloy. The cylinder 11 has a closed end at a lower portion, and a bush fitting hole 13 penetrating on both sides is provided in a connecting piece 12 provided at the closed end. The bush 14 inserted into the bush fitting hole 13 is fixed to the pulley arm 1 by tightening a bolt 15 screwed into the pulley arm 1.

  A sleeve fitting hole 16 is formed in the inner bottom surface of the cylinder 11, and a sleeve 17 with a steel bottom is fitted into the sleeve fitting hole 16. A retaining ring 18 is attached to the lower periphery of the sleeve 17.

  A piston 20 formed at the lower end of the rod 19 is slidably inserted into the sleeve 17, and a pressure chamber 21 is formed in the sleeve 17 by the insertion of the piston 20.

  A spring seat 22 is attached to the upper end of the rod 19 facing the outside of the cylinder 11. The spring seat 22 has a connecting piece 23 at the top, and the connecting piece 23 is provided with bush insertion holes 24 penetrating on both sides.

  The bush 25 inserted into the bush insertion hole 24 is fixed to the engine block 26 by tightening a bolt 27 screwed into the engine block 26, and the hydraulic auto tensioner 10 is swingable about the bush 25.

  A rod support 28 is attached to the upper portion of the rod 19. The rod support 28 has an end plate 28 a that abuts against the lower surface of the spring seat 22, and an inner cylinder portion 28 b that is press-fitted into the outer periphery of the rod 19 is provided on the inner periphery of the end plate 28 a. An outer cylinder portion 28c is formed on the outer periphery of the end plate 28a, and a large-diameter cylinder portion 28d provided at the lower end portion of the outer cylinder portion 28c is slidable along the inner diameter surface of the cylinder 11. .

  By attaching the rod support 28 to the upper outer periphery of the rod 19, a first reservoir chamber 29 is provided inside the rod support 28, and the return spring 30 incorporated in the first reservoir chamber 29 has a relative relationship between the cylinder 11 and the rod 19. The cylinder 11 and the rod 19 are urged in the direction in which they are extended.

  A retaining ring 31 is attached to the inner periphery of the opening of the cylinder 11. The retaining ring 31 can be engaged with a shoulder portion 28e of a large diameter cylindrical portion 28d provided on the rod support 28, and the cylinder 11 and the rod support 28 are not separated in the axial direction by the engagement.

  An expandable / contractible bellows 32 is provided outside the rod support 28. One end of the bellows 32 is connected to the spring seat 22, and the other end is connected to the outer periphery of the opening end of the cylinder 11. The bellows 32 forms a second reservoir chamber 33 with the rod support 28.

  The pressure chamber 21 and the first reservoir chamber 29 communicate with each other through a first passage 34 formed on the outer periphery of the piston 20.

  As shown in FIGS. 4 and 5, the first passage 34 includes a plurality of grooves extending in the axial direction. The first passage 34 is opened and closed by a check valve 35. The check valve 35 has an orifice plate 36 attached to the lower end portion of the rod 19, and a seal ring 38 that is elastically deformable in the radial direction in a ring groove 37 formed between the orifice plate 36 and the lower surface of the piston 20. The plate 36 is provided with a plurality of oil passage holes 39 communicating with the ring groove 37 and the pressure chamber 21, and when the pressure in the pressure chamber 21 becomes higher than the pressure in the first reservoir chamber 29, the seal ring 38 is attached to the lower surface of the piston 20. The first passage 34 is closed by increasing the diameter until it is in close contact with the inner surface of the sleeve 17 until it is in close contact with the inner diameter surface of the sleeve 17.

  As shown in FIG. 2, the pressure chamber 21 and the second reservoir chamber 33 communicate with each other by a second passage 40 formed in the rod 19 and the spring seat 22.

  The second passage 40 is provided with a throttle portion 41 and an electromagnetic opening / closing valve 42. As shown in FIG. 4, the throttle portion 41 includes an orifice formed in the orifice plate 36. The throttle portion 41 is hydraulic fluid that flows from the pressure chamber 21 to the second passage 40 when a pressure is applied in a direction in which the cylinder 11 and the rod 19 are relatively contracted to increase the pressure in the pressure chamber 21. Regulate the flow rate. The pressing force is buffered by the hydraulic oil in the pressure chamber 21 by the flow rate restriction.

  As shown in FIGS. 2 and 3, the electromagnetic opening / closing valve 42 is incorporated in a valve insertion hole 43 extending from one side surface of the spring seat 22 to a part of the second passage 40. This electromagnetic on-off valve 42 controls a valve sleeve 44 with a flange inserted into the valve insertion hole 43, a spherical valve body 45 and a spring 46 incorporated in the valve sleeve 44, and opening and closing of the valve body 45. The actuator comprises a direct acting solenoid 47 as an actuator and a cover 48 covering the solenoid 47.

  The valve sleeve 44 has a closed end, and a valve hole 49 is formed at the closed end. The valve sleeve 44 is provided with an oil passage hole 50 that communicates the inside with the second passage 40.

  The valve body 45 opens and closes the valve hole 49, and the spring 46 biases the valve body 45 in a direction to close the valve hole 49.

  The solenoid 47 includes a case 51 made of a magnetic material, a bobbin 52 incorporated in the case 51, an electromagnetic coil 53 wound around the bobbin 52, and a push that slidably penetrates the end plate of the case 51. When the electromagnetic coil 53 is energized, a magnetic attraction force is applied to the plunger 55 and moves toward the case 51, and the plunger 55 is composed of a rod 54 and a plunger 55 fixed to the rear end of the push rod 54. The push rod 54 that moves together with the valve 46 presses the valve element 45 via the spring 46, and the valve element 45 is held in a state in which the valve hole 49 is closed by the pressing.

  As shown in FIG. 2, the second reservoir chamber 33 and the first reservoir chamber 29 communicate with each other via a third passage 56 formed by a groove formed on the inner periphery of the opening end of the cylinder 11.

  The hydraulic auto tensioner shown in the embodiment has the above structure. When the engine 5 and the auxiliary machine 7 are driven by the motor / generator 6 shown in FIG. 8, the electromagnetic coil 53 of the solenoid 47 shown in FIG. On the other hand, during normal travel by driving the engine 5, the energization of the electromagnetic coil 53 is cut off.

  Now, when the electromagnetic coil 53 is energized, the push rod 54 is moved in the axial direction by the electromagnetic attractive force applied to the plunger 55, the spring 46 contracts as shown in FIG. 3, and the valve body 45 opens the valve hole 49. The electromagnetic open / close valve 42 is closed and kept closed.

  For this reason, when the engine 5 is driven by the motor / generator 6 and the tension of the belt 4 increases, a pushing force is applied from the belt 4 to the cylinder 11 via the pulley arm 1 and the pressure in the pressure chamber 21 increases. Since the second passage 40 is closed by the electromagnetic opening / closing valve 42, the hydraulic oil in the pressure chamber 21 does not flow into the second passage 40.

  When the pressure in the pressure chamber 21 rises, the seal ring 38 comes into close contact with the lower surface of the piston 20 and expands in diameter to close the first passage 34 as shown in FIG. For this reason, the hydraulic oil in the pressure chamber 21 does not flow into the first reservoir chamber 29 and moves in a direction in which the cylinder 11 and the rod 19 are relatively contracted by the hydraulic oil sealed in the pressure chamber 21. And the tension pulley 3 is fixed in place.

  Thus, since the tension pulley 3 can be fixed at a fixed position by energizing the electromagnetic coil 53, the belt 4 can be prevented from slipping and the engine can be started stably.

  After the engine is started by the motor / generator 6, when the electromagnetic coil 53 is deenergized during normal travel by driving the engine 5, the push rod 54 and the plunger 55 are retracted by the restoring elasticity of the spring 46, and the valve body 45 is moved to the spring 46. By pressing the valve hole 49, the valve hole 49 is held in a closed state from one direction, and the electromagnetic on-off valve 42 is in a state of exhibiting a function as a check valve.

  When the auxiliary machine 7 is driven by the engine 5, the tension of the belt 4 changes due to the load fluctuation of the auxiliary machine 7, and when the tension of the belt 4 increases and the cylinder 11 is pushed up, the pressure in the pressure chamber 21 is increased. As shown in FIG. 4, the seal ring 38 comes into close contact with the lower surface of the piston 20 and expands in diameter to close the first passage 34 as described above.

  Therefore, the hydraulic oil in the pressure chamber 21 is prevented from flowing from the first passage 34 to the first reservoir chamber 29, and the throttle passage 41 is provided in the second passage 40. The push-up force applied to the cylinder 11 is buffered by the hydraulic oil enclosed in the cylinder.

  When the push-up force is higher than the pressing force of the return spring 30, hydraulic oil flows from the pressure chamber 21 through the throttle portion 41 into the second passage 40, and the valve body 45 of the electromagnetic on-off valve 42 is moved by the pressure of the hydraulic oil. As a result, the valve hole 49 is opened as shown in FIG.

  For this reason, the hydraulic oil that has flowed into the second passage 40 flows into the second reservoir chamber 33, and from the second reservoir chamber 33 to the third passage 56 and into the first reservoir chamber 29, and the above-described pushing force The cylinder 11 and the rod 19 contract relatively slowly to a position where the pressing force of the return spring 30 is balanced.

  On the other hand, when the tension of the belt 4 becomes weak, the cylinder 11 moves in the direction of extending with respect to the rod 19 by the pressing force of the return spring 30, the pulley arm 1 swings, and the tension pulley 3 is pressed against the belt 4. Absorbs 4 slack.

  When the cylinder 11 moves relative to the rod 19 in the extending direction, the pressure in the pressure chamber 21 decreases and becomes lower than the pressure in the first reservoir chamber 29, so that the seal ring 38 is separated from the lower surface of the piston 20. The first passage 34 opens as shown in FIG.

  Therefore, the hydraulic oil in the first reservoir chamber 29 flows into the ring groove 37 from the first passage 34, and flows into the pressure chamber 21 from the ring groove 27 through the oil passage hole 39. For this reason, the cylinder 11 moves smoothly in the extending direction and immediately absorbs the slack of the belt 4.

  As described above, when the electromagnetic on-off valve 42 releases the closed state of the valve body 45, the hydraulic auto tensioner 10 immediately responds to fluctuations in the tension of the belt 4 to keep the belt 4 at an appropriate tension. Thus, it is possible to suppress the life reduction of the belt 4 and to prevent the generation of abnormal noise due to the flapping of the belt 4.

  In the embodiment, the solenoid 47 is used as an actuator as a drive source of the electromagnetic on-off valve 42, but the actuator is not limited to this. For example, a linear motor (voice coil motor) may be used.

The front view which shows the use condition of the hydraulic auto tensioner which concerns on this invention Longitudinal front view of hydraulic auto tensioner Sectional view showing a part of the solenoid valve Enlarged sectional view of the check valve Sectional view along line VV in FIG. Sectional view showing the open state of the solenoid valve Sectional view showing open state of check valve The figure which shows the starting state of the engine with the motor generator The figure which shows the drive state of the auxiliary machine with the engine

Explanation of symbols

11 Cylinder 16 Sleeve fitting hole 17 Sleeve 19 Rod 20 Piston 21 Pressure chamber 22 Spring seat 28 Rod support 28a End plate 28b Inner tube portion 28c Outer tube portion 29 First reservoir chamber 30 Return spring 31 Retaining ring 32 Bellows 33 Second reservoir Chamber 34 First passage 35 Check valve 36 Orifice plate 37 Ring groove 38 Seal ring 39 Oil passage hole 40 Second passage 41 Restriction portion 42 Electromagnetic switching valve 44 Valve sleeve 45 Valve body 47 Solenoid 49 Valve hole 56 Third passage

Claims (6)

  A cylinder having a closed end, a bottomed sleeve having a lower end fitted in a sleeve fitting hole formed in the inner bottom surface of the cylinder, and a piston slidable in the sleeve at the lower end A rod that forms a pressure chamber in the sleeve by the piston, a spring seat fixed to an upper end portion of the rod outside the cylinder, and an inner periphery of the end plate that abuts the lower surface of the spring seat. An inner cylinder portion fixed to the rod is provided, and a lower end portion of the outer cylinder portion formed on the outer periphery of the end plate is slidably fitted into the cylinder so that the first reservoir chamber is interposed between the rod and the rod. A rod support to be formed, an extendable bellows having one end connected to the upper outer periphery of the cylinder and the other end connected to the spring seat to form a second reservoir chamber between the rod support and the cylinder And the rod A return spring for urging the cylinder and the rod in the lengthwise direction; a first passage for communicating the pressure chamber and the first reservoir chamber is provided between the sleeve and the sliding surface of the piston; Provided with a check valve for closing the first passage when the pressure in the pressure chamber becomes higher than the pressure in the first reservoir chamber. The rod and the spring seat have a second passage communicating the pressure chamber and the second reservoir chamber. The throttle passage and the electromagnetic on-off valve that closes the second passage by energizing the actuator are provided in the second passage, and the first reservoir chamber and the first passage are provided between the outer cylinder portion of the rod support and the sliding surface of the cylinder. 2 Hydraulic auto tensioner provided with a third passage communicating with the reservoir chamber.   The check valve is attached to the lower end portion of the rod to form a ring groove between the lower surfaces of the piston, and an orifice plate having an oil passage hole communicating the ring groove and the pressure chamber is incorporated in the ring groove. 2. The seal ring according to claim 1, further comprising a seal ring that is axially movable and closes the first passage when in close contact with the lower surface of the piston when the pressure in the pressure chamber becomes higher than the pressure in the first reservoir chamber. Hydraulic auto tensioner.   3. The electromagnetic open / close valve according to claim 1 or 2, comprising a valve sleeve having a valve hole formed at a closed end, a valve body for opening / closing the valve hole of the valve sleeve, and an actuator for opening / closing the valve body. Hydraulic auto tensioner.   The hydraulic auto tensioner according to any one of claims 1 to 3, wherein the actuator comprises a direct acting solenoid.   The hydraulic auto tensioner according to any one of claims 1 to 3, wherein the actuator comprises a linear motor.   The hydraulic auto tensioner according to any one of claims 1 to 5, wherein a retaining ring for restricting relative expansion of the cylinder and the rod support is attached to an inner periphery of the opening end of the cylinder.

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