JP2008175258A - Tension regulating device for auxiliary machine drive belt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tension regulating device for an auxiliary machine drive belt capable of easily pushing and retracting a hydraulic automatic tensioner for regulating the tension of the belt in an assembled state and prevented from being erroneously extended during retracting work of the tensioner. <P>SOLUTION: Regulating force of the extensible hydraulic automatic tensioner 10 is applied to push a tension pulley 8 against the belt 5. A screw shaft of a boss 40 comprised of a headed bolt is threadedly engaged in a screw hole formed at an eccentric position to a pivot center of a pulley arm 6. A winding direction of a screw thread of the screw shaft is so set that it is loosed when a wrench T engaged with the head 42 of the boss 40 is pivoted in a wrong direction, when the wrench T engaged with the head 42 of the boss 40 is pivoted in one direction, the pulley arm 6 is pivoted and the hydraulic automatic tensioner 10 is retracted and when pivoted in the other direction, the pulley arm 6 is not pivoted. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a belt tension adjusting device for driving an automobile auxiliary machine such as an alternator, a water pump, and an air conditioner compressor.

  In belt transmissions that transmit engine crankshaft rotation to various automotive accessories, a swingable pulley arm that supports a tension pulley is provided on the slack side of the belt, and the adjustment force of a hydraulic auto tensioner is applied to the pulley arm. The tension pulley urges the pulley arm in the direction in which the belt is pressed, so that the belt tension is kept constant.

  As a hydraulic auto tensioner used in belt transmissions, the opening end of a cylinder filled with hydraulic oil is sealed by mounting an oil seal, and the oil seal is slidably passed through between the rod and the cylinder. When a spring is installed and the cylinder and rod are urged in the direction of relative expansion, and a pushing force is applied in the direction of contraction of the cylinder and rod, the cylinder is buffered by a hydraulic damper built into the cylinder. A telescopic hydraulic auto tensioner adapted to do so is known.

  In the belt drive device for driving an auxiliary machine incorporating the telescopic hydraulic auto tensioner as described above, the belt is attached and detached while the hydraulic auto tensioner is contracted when the belt is replaced. However, since a hydraulic damper is built in the hydraulic auto tensioner, it is necessary to apply a large pushing force to overcome the hydraulic pressure when contracting, and the contracting work is extremely difficult. .

  Therefore, by providing a wrench engaging boss having a square outer periphery at an eccentric position with respect to the swing center of the pulley arm, and engaging the wrench with the boss and swinging the wrench, a relatively small swing operation force can be obtained. Since a large rotational moment can be applied to the pulley arm, the hydraulic auto tensioner can be easily contracted, which is effective in eliminating the above disadvantages.

  By the way, when the pulley arm is provided with a boss, the contraction work for pushing and shrinking the hydraulic auto tensioner is performed in a state where the engine is mounted on the automobile vehicle, so it is difficult to confirm the direction in which the hydraulic auto tensioner is pushed and shrunk. There is a risk that the wrench may be swung in the wrong direction.

  At this time, since the hydraulic auto tensioner can be stretched with a relatively small force in the extension direction, it may be stretched suddenly, and at that time, a large impact force is added to the hydraulic auto tensioner, causing damage. Or may be decomposed.

  Further, if the hydraulic auto tensioner is used in a damaged state, the belt may be damaged or broken, or abnormal noise may be generated.

  An object of the present invention is to provide an auxiliary machine driving belt that can easily be compressed in an assembled state with a hydraulic auto tensioner that adjusts the tension of the belt and that is not accidentally extended during the contraction operation. It is to provide a tension adjusting device.

  In order to solve the above-mentioned problems, in the present invention, a swingable pulley arm that rotatably supports a tension pulley is biased in a direction in which it is extended by a return spring, and a pushing force in a contracting direction to be loaded is incorporated. An eccentric position with respect to the swing center of the pulley arm is applied by applying an adjustment force of a telescopic hydraulic auto tensioner that is buffered by a hydraulic damper and urging the pulley arm in a direction in which the tension pulley presses the belt for driving the accessory. A wrench engaging boss with a square outer periphery is provided on the auxiliary drive belt, and the pulley arm is swung in a direction in which the hydraulic auto tensioner contracts by a one-way swing operation of the wrench engaged with the boss. In the tension adjusting device, the boss is attached to the pulley arm by screw engagement, and the thread of the screw engagement portion is Than it is adopted the configuration in which there is a winding direction as loosening occurs when the rotational torque to the boss is loaded by swinging in the other direction of the bench.

  Here, the boss may be made of a bolt having a square head for engaging with a wrench, or may be made of a nut having a square outer periphery. In the case of a boss made of a bolt, the screw shaft is screwed into a screw hole formed in the pulley arm, and the head is subjected to rotational torque by swinging the screw thread formed on the screw shaft in the other direction of the wrench. The winding direction is such that slack is generated.

  On the other hand, in the case of a boss composed of a nut, the thread of a female screw formed on the nut is wound so that loosening occurs when a rotational torque is applied to the nut by swinging the wrench in the other direction.

  As described above, a boss with a square outer periphery is attached by screw engagement at an eccentric position with respect to the swing center of the pulley arm, and the rotational torque is applied to the boss by swinging the thread of the screw engagement portion in the other direction of the wrench. When the wrench is engaged with the boss and swung in one direction, the boss is tightened and the operating force of the wrench is transmitted to the pulley arm via the boss. As a result, the pulley arm swings, and a large rotational moment can be applied to the pulley arm. For this reason, the hydraulic auto tensioner can be easily contracted by a relatively small operating force, and the belt replacement work can be easily performed.

  When the wrench is swung in the other direction, the boss is slackened, and the operating force of the wrench is not transmitted to the pulley arm, and the pulley arm cannot be swung in the direction in which the hydraulic auto tensioner extends. For this reason, it is possible to prevent the hydraulic auto tensioner from being accidentally extended when the hydraulic auto tensioner is contracted.

  Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, a belt 5 is stretched between a pulley 2 attached to the end of the crankshaft 1 and a pulley 4 attached to the rotary shaft 3 of the auxiliary machine, and the outer side of the slack side belt 5a of the belt 5 A pulley arm 6 is provided on the side.

  The pulley arm 6 is swingably supported around a shaft 7 supported by the engine block, and a tension pulley 8 is rotatably supported at the swing side end of the pulley arm 6.

  The pulley arm 6 is connected to a telescopic hydraulic auto tensioner 10, and the pulley arm 6 is urged by the hydraulic auto tensioner 10 in a direction in which the tension pulley 8 presses the belt 5.

  As shown in FIG. 2, the hydraulic auto tensioner 10 has a bottomed cylindrical cylinder 11 whose upper end is open. The cylinder 11 is made of an aluminum alloy, and a steel bottomed cylindrical sleeve 12 is fitted therein.

  The inside of the cylinder 11 is filled with hydraulic oil, and the hydraulic oil is prevented from leaking to the outside by an oil seal 13 that seals the upper opening of the cylinder 11. The oil seal 13 is retained by a retaining ring 14 attached to the inner periphery of the cylinder 11, and the retaining ring 14 and a rod 15 inserted through the center of the oil seal 13 are slidable in the axial direction.

  A spring seat 16 is attached to the upper end portion of the rod 15 located outside the cylinder 11, and the rod 15 and the cylinder 11 are urged in the extension direction between the spring seat 16 and a flange 17 provided at the lower outer periphery of the cylinder 11. A return spring 18 is incorporated.

  A connecting piece 19 is formed on the upper surface of the spring seat 16, and the connecting piece 19 is swingably connected to an engine block (not shown). On the other hand, a connecting piece 20 is also provided at the lower end of the cylinder 11, and the connecting piece 20 is swingably connected to the pulley arm 6 via a bolt 21 screwed into the pulley arm 6, and the pulley arm 6 is centered on the shaft 7. Then, when swinging in the direction of the arrow in FIG. 2, the hydraulic auto tensioner 10 is contracted.

  A hydraulic damper 30 is incorporated in the sleeve 12 to buffer the pushing force applied to the rod 15.

  The hydraulic damper 30 connects a plunger 31 slidable along the inner diameter surface of the sleeve 12 to the lower end of the rod 15 to partition the inside of the sleeve 12 into a pressure chamber 32 and a reservoir chamber 33, and the plunger 31 has a lower portion thereof. A passage 34 communicating with the pressure chamber 32 and the upper reservoir chamber 33 is provided, and the passage 34 is closed at the opening of the passage 34 on the pressure chamber 32 side when the pressure in the pressure chamber 32 becomes higher than the pressure in the reservoir chamber 33. The check valve 35 is provided to buffer the pushing force in the direction in which the cylinder 11 and the rod 15 are contracted by the hydraulic oil sealed in the pressure chamber 32. Reference numeral 36 denotes a plunger spring that presses the plunger 31 against the lower end of the rod 15.

  In the hydraulic auto tensioner 10 having the above-described configuration, when the tension of the belt 5 changes due to the load fluctuation of the auxiliary machine driven by the belt 5 and the change of the angular velocity of the crankshaft 1, the belt 5 becomes slack. When the return spring 18 is pressed, the cylinder 11 and the rod 15 move relative to each other in the extending direction to absorb the slack of the belt 5.

  At this time, since the plunger 31 also moves in the same direction as the rod 15, the volume of the pressure chamber 32 increases and the pressure decreases. When the pressure becomes lower than the pressure in the reservoir chamber 33, the check valve 35 opens the passage 34. Therefore, the hydraulic oil in the reservoir chamber 33 flows from the passage 34 to the pressure chamber 32, and the rod 15 and the plunger 31 move rapidly outward to immediately absorb the slack of the belt 5.

  On the other hand, when the tension of the belt 5 increases, the pushing force in the direction of contracting the cylinder 11 and the rod 15 is applied from the belt 5 to the hydraulic auto tensioner 10 via the tension pulley 8 and the pulley arm 6. At this time, since the pressure in the pressure chamber 32 becomes higher than the pressure in the reservoir chamber 33, the check valve 35 closes the passage 34 and is loaded on the hydraulic auto tensioner 10 by the hydraulic oil sealed in the pressure chamber 32. The pushing force is buffered.

  When the pushing force is larger than the elastic force of the return spring 18, the hydraulic oil in the pressure chamber 32 flows into the reservoir chamber 33 through a minute leak gap formed between the sleeve 12 and the sliding surface of the plunger 31, and the pushing force and The cylinder 11 and the rod 15 slowly move relative to each other in a contracting direction until the elastic force of the return spring 18 is balanced, and the tension of the belt 5 is kept constant.

  As shown in FIGS. 2 and 3, a boss 40 is provided at an eccentric position with respect to the swing center of the pulley arm 6. The boss 40 is composed of a bolt having a head 42 at the end of the screw shaft 41, and the head 42 is formed in a square shape so that a wrench T such as an eyeglass wrench can be engaged therewith.

  The boss 40 is attached by screw engagement of the screw shaft 41 with the screw hole 43 formed in the pulley arm 6. Here, the thread formed on the outer periphery of the screw shaft 41 is fastened when the wrench T engaged with the head 42 is oscillated in one direction indicated by an arrow, and the other direction (the opposite direction indicated by the arrow). The winding direction is such that it will loosen when swinging.

  The tension adjusting device for an auxiliary machine driving belt shown in the embodiment has the above-described structure. When the belt 5 is removed or the belt 5 is attached by replacing the belt, the cylinder 11 and the rod 15 of the hydraulic auto tensioner 10 are moved relative to each other. The hydraulic auto tensioner 10 is contracted by relative movement in the contracting direction, and the belt 5 is exchanged in a state where the belt 5 is slackened.

  When the hydraulic auto tensioner 10 contracts, as shown in FIG. 2, a wrench T is engaged with the head 42 of the boss 40, and the wrench T is swung in one direction indicated by an arrow in the figure. When the wrench T swings in the direction of the arrow, the screw shaft 41 of the boss 40 is tightened, so that the operating force of the wrench T is applied from the boss 40 to the pulley arm 6. The pulley arm 6 swings about the shaft 7 by the load of the operating force, and the hydraulic auto tensioner 10 contracts.

  As described above, the contraction operation of the hydraulic auto tensioner 10 is based on the swing of the wrench T engaged with the head portion 42 of the boss 40, so that a large rotational moment can be applied to the pulley arm 6. The hydraulic auto tensioner 10 can be easily contracted by force. Accordingly, the belt 5 can be easily replaced.

  Since the operation of contracting the hydraulic auto tensioner 10 is performed in a state where the engine is mounted on the vehicle, it is difficult to confirm the direction in which the hydraulic auto tensioner 10 is contracted, and the wrench T is in the wrong direction (arrow May swing in the opposite direction).

  In this case, since the screw shaft 41 is slackened by the rotational torque applied from the wrench T to the head portion 42 of the boss 40, no rotational moment is applied to the pulley arm 6, and the pulley arm 6 does not swing.

  For this reason, when the hydraulic auto tensioner 10 is contracted, the hydraulic auto tensioner 10 is not expanded by mistake, and there is no inconvenience that the hydraulic auto tensioner 10 is damaged or disassembled.

  In the embodiment shown in FIG. 3, the boss 40 is made of a bolt. However, as shown in FIG. 4, the boss 40 may be made of a nut. In the case of the boss 40 made of a nut, a stud bolt 44 is fixed to the pulley arm 6, and the boss 40 made of a nut is screw-engaged with the stud bolt 44.

  At this time, the thread of the internal thread formed on the inner periphery of the boss 40 is tightened when the wrench T engaged with the boss 40 is swung in one direction indicated by an arrow in FIG. The winding direction is set so as to be loose when it is swung in the opposite direction indicated by the arrow. Even in this case, when the wrench T is swung in the wrong direction during the operation of contracting the hydraulic auto tensioner by the swinging operation of the wrench T engaged with the boss 40, the boss 40 is loosened. The pulley arm 6 does not swing, and the hydraulic auto tensioner 10 can be prevented from being accidentally extended.

Front view of tension adjusting device for auxiliary machine driving belt according to this invention Sectional drawing which expands and shows the part of the hydraulic auto tensioner of FIG. Sectional view along line III-III in FIG. Sectional view showing another example of boss

Explanation of symbols

6 Pulley arm 8 Tension pulley 10 Hydraulic auto tensioner 18 Return spring 30 Hydraulic damper 40 Boss 41 Screw shaft 42 Head 43 Screw hole 44 Stud bolt

Claims (3)

A telescopic hydraulic auto tensioner that is urged by a return spring on a swingable pulley arm that rotatably supports a tension pulley and that absorbs the pushing force in the contracting direction to be loaded by a built-in hydraulic damper. The tension pulley urges the pulley arm in the direction in which the tension pulley presses the belt for driving the accessory, and a wrench engaging boss having a square outer periphery is provided at an eccentric position with respect to the swing center of the pulley arm. In the tension adjusting device for the accessory driving belt, the pulley arm is swung in the direction in which the hydraulic auto tensioner contracts by the swinging operation in one direction of the wrench engaged with the
A winding direction in which the boss is attached to the pulley arm by screw engagement, and the thread of the screw engagement portion is loosened when a rotational torque is applied to the boss by swinging the wrench in the other direction. A tension adjusting device for a belt for driving an auxiliary machine, characterized in that   The boss is formed of a bolt having a square head for engaging a wrench, and the screw shaft of the bolt is screw-engaged with a screw hole formed in a pulley arm, and the thread formed on the screw shaft is moved in the other direction of the wrench. 2. The tension adjusting device for an auxiliary machine driving belt according to claim 1, wherein the winding direction is such that a slack is generated when a rotational torque is applied to the head portion by swinging.   The boss consists of a square nut, and the nut is screw-engaged with a stud bolt attached to the pulley arm, and the screw thread of the female thread formed on the nut is rotated to the nut by swinging in the other direction of the wrench. The tension adjusting device for an auxiliary machine driving belt according to claim 1, wherein the winding direction is such that loosening occurs when a load is applied.

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