JP2007032711A - Hydraulic auto-tensioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydraulic auto-tensioner having excellent maintenance property and excellent property for preventing oil from scattering to the outside. <P>SOLUTION: This hydraulic auto-tensioner is constituted by forming a sealed reservoir chamber 29 among a cylinder 11, a sleeve 14, and a rod 16 by connecting an outer peripheral face of a cylindrical body 27 with an upper part of the outer periphery of the cylinder 11 by bellows 28, providing a check valve 32 for closing a passage when pressure in a pressure chamber 18 becomes higher than pressure in the reservoir chamber 29, and providing a second passage 33 for circulating hydraulic fluid in the pressure chamber 18 onto a reservoir chamber 29 side through a restriction part 34 formed along a shaft axis of a piston 17 or a clearance part of the piston and the sleeve. A channel 24 extending in the direction of cylinder length and a peripheral channel 25 crossing the channel 24 are formed on the outer peripheral face of the cylindrical body 27. A lower part of the cylindrical body 27 is formed to have smaller diameter than that of an upper part. A channel 28b extending in the direction of cylinder length is provided on a cylindrical body contact face on an inner side of the bellows 28, and the channel 28b and a channel 24 extending in the direction of cylinder length on the outer peripheral face of the cylindrical body 27 are arranged in such a way that they are overlapped by facing each other. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a hydraulic auto tensioner that maintains a constant tension of a belt for driving auxiliary equipment such as a compressor and a water pump of an air conditioner such as an automobile.

  A motor / generator is installed, and during normal driving, the motor / generator is switched to a power generation operation, the drive wheels are rotated by driving the engine, and the motor / generator and the compressor of the air conditioner are driven. On the other hand, when the vehicle is stopped, in an idle stop compatible vehicle in which the engine is stopped and the motor / generator is switched to the driving operation to drive the auxiliary machine, the motor The engine is driven by a generator.

5 and 6 show a schematic configuration of a belt transmission device for driving an auxiliary machine of an idle stop-compatible vehicle. Among these, FIG. 5 shows an engine 5 and an auxiliary machine 7 by a motor / generator 6 switched to a starting operation. The state which is driving is shown.
FIG. 6 shows a state in which the motor / generator 6 and the auxiliary machine 7 switched to the power generation operation by the engine 5 are driven.

  In such an auxiliary machine driving belt transmission, 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 that supports the tension pulley 3 is adjusted with the auto tensioner A. A force is applied to keep the tension of the belt 4 constant.

  7 known as the auto tensioner A shown in FIG. 7 absorbs a change in belt tension by a return spring 52 and a hydraulic damper mechanism (a mechanism having the same configuration as the first passage 31 and the check valve 32 in FIG. 2). The rod 54 and the piston 55 are slidably inserted into the sleeve 53 to form a pressure chamber 56 below, and hydraulic oil can be circulated between the piston 55 and the rod 54 and the sleeve 53. A gap a is formed, and between the spring seat 58 and the inner bottom surface of the cylinder 51, a return spring 52 that urges the cylinder 51 and the rod 54 in the extending direction is incorporated (see Patent Document 1).

  Such an auto tensioner can be employed in the belt transmission shown in FIGS. 5 and 6, but when the engine 5 is driven by the motor / generator 6 of the belt transmission (see FIG. 5), the belt load increases rapidly. Therefore, excessive belt tension may act on the hydraulic auto tensioner.

  At this time, in the hydraulic auto tensioner, the hydraulic oil in the pressure chamber 56 flows to the reservoir chamber 59 side through the gap a between the piston 55 (and the rod 54) and the sleeve 53, and the return spring 52 is compressed and compressed. The auto tensioner shrinks until the belt tension is stable.

  Further, when the tension of the belt 4 is weakened when the engine 5 is driven (see FIG. 6), the cylinder 51 moves in the direction of extending with respect to the rod 54 by the pressing force of the return spring 52, and the pulley arm 1 is shaken by the movement. The tension pulley 3 is pressed against the belt 4 to absorb the slack of the belt.

  By the way, one end of an extendable bellows 61 is connected to the outer peripheral surface of the cylindrical body 57 covering the upper end of the return spring 52 to the spring seat 58 of the hydraulic auto tensioner shown in FIG. The end is connected to the upper outer periphery of the cylinder 51.

  Therefore, when the hydraulic auto tensioner is sufficiently contracted, the air pressure inside the bellows 61 increases, and the bellows 61 is elastically deformed by the pressure, and air leaks to the outside from the gap with the cylindrical body 57. May happen.

  If such a leak often occurs, the connecting position of the bellows 61 may be shifted by the leaked air flow, and the reliable operation of the hydraulic auto tensioner may be impaired. A plurality of grooves 62 extending along the cylinder length direction are formed on the inner side of the contact surface with the cylinder 57 of the bellows 61 at intervals in the circumferential direction. When the pressure inside the bellows 61 is excessively high, the grooves 62 are formed. It was designed so that air can escape from the notch 61a at the edge via the air and can be decompressed relatively easily.

  Further, a plurality of grooves 63 extending in the cylinder length direction are formed on the outer peripheral surface of the cylinder body 57 at intervals in the circumferential direction, and air is guided from the groove 63 to a portion of the bellows 61 where the groove 62 is not provided. The air pressure was applied as uniformly as possible inside.

Special Table 2000-504395

  However, in the conventional hydraulic auto tensioner described above, when the air pressure inside the bellows 61 is excessively increased and air is released from the groove 62 to the outside, air containing steam or oil droplets of the working oil passes through the groove 62. Therefore, there is a case where the hydraulic oil is gradually accumulated in the gap between the bellows 61 and the cylindrical body 57 and is scattered as an oil droplet to the outside along with the air flow.

  If such hydraulic oil scatters to the outside, the hydraulic oil adheres to the belt 4 and deteriorates, or the amount of hydraulic oil consumed increases, adversely affecting the maintenance of the hydraulic auto tensioner. It also becomes.

  SUMMARY OF THE INVENTION Accordingly, the object of the present invention is to solve the above-described problems and collect hydraulic oil contained in the air that has entered the gap between the bellows and the cylindrical body in the hydraulic auto tensioner and prevent scattering to the outside. In particular, the hydraulic auto-tensioner is required to have a low maintenance frequency and is excellent in preventing deterioration of peripheral equipment due to scattered oil.

  In order to solve the above-mentioned problems, in the present invention, a sleeve is provided in a cylinder whose lower end is closed, and a piston provided at the lower end of the rod is slidably inserted into the sleeve so as to press the piston downward. A cylindrical body that forms a chamber and incorporates a return spring that urges the cylinder and the rod in an extending direction between a spring seat provided at the top of the rod and the inner bottom surface of the cylinder, and covers the upper end of the return spring Is formed integrally with the spring seat, and a reservoir chamber sealed between the cylinder, the sleeve and the rod is formed by connecting the outer peripheral surface of the cylindrical body and the outer peripheral upper portion of the cylinder with a bellows. A check valve that closes the passage when the pressure in the pressure chamber becomes higher than the pressure in the reservoir chamber, in a first passage communicating the lower portion of the pressure chamber and the lower portion of the pressure chamber In a hydraulic auto tensioner provided with a second passage through which hydraulic oil in the pressure chamber flows to the reservoir chamber side via a throttle portion formed along the axis of the piston or a gap between the piston and a sleeve, One or more grooves extending in the cylinder length direction are formed on the outer peripheral surface of the cylindrical body, and a peripheral groove that intersects with the grooves is formed.

  The hydraulic auto tensioner configured as described above has a large amount of oil droplets outside of the air flow along with the air flow even if air containing the vapor of hydraulic oil enters the gap between the cylinder and the bellows to form oil droplets. Cannot cross the circumferential groove before leaking into The hydraulic oil temporarily stored in the circumferential groove travels through a groove extending in the cylinder length direction on the outer peripheral surface of the cylinder, and is recovered from the bottom end of the cylinder by gravity or vibration to the reservoir chamber.

  Incidentally, some of the oil droplets that accumulate in the gap with the bellows above the circumferential groove of the cylindrical body are scattered outside along with the air flow, but most of them flow into the circumferential groove due to gravity and are collected into the reservoir chamber. Therefore, the amount of oil leaking to the outside is extremely small.

  In order to return the oil droplets to the reservoir chamber as efficiently as possible, it is preferable that the circumferential groove formed in the cylindrical body is disposed on the surface where the bellows contacts along the thick edge provided on the end edge of the bellows. . This is because oil droplets easily collect in or around the circumferential groove where the thick edge of the bellows is fitted and locked, and these are collected and efficiently collected in the circumferential groove.

  Further, in order to efficiently recover the hydraulic oil from the groove extending in the cylinder length direction on the outer peripheral surface of the cylinder, the peripheral groove is formed in the upper part of the cylinder, and the lower part of the cylinder is formed in a smaller diameter than the upper part. It is preferable. This is because if the lower part of the cylinder is kept away from the bellows, the oil droplets will naturally flow into the reservoir chamber.

  If a groove extending along the cylinder length direction is provided inside the cylinder contact surface of the bellows, the bellows can be ventilated by only slightly elastically deforming along the groove when the auto tensioner is contracted. The

  Further, in order to prevent oil droplets from accumulating as much as possible in the gap between the cylinder and the bellows, a groove extending along the cylinder length direction inside the cylinder contact surface of the bellows, and extending in the cylinder length direction on the outer peripheral surface of the cylinder It is preferable that the hydraulic auto tensioner is arranged such that one or more grooves face each other and overlap each other.

  By arranging the groove provided on the inner side of the bellows cylinder contact surface and the groove formed on the outer peripheral surface of the cylinder so as to face each other, two grooves can be assembled to form a relatively large groove. By such a collecting groove, the elastic deformation of the bellows becomes smaller, the positional deviation becomes smaller, and oil droplets can be prevented from being accumulated as much as possible by smooth ventilation.

  According to the present invention, a groove extending in the cylinder length direction is formed on the outer peripheral surface of the cylinder of the hydraulic auto tensioner, and a circumferential groove intersecting the groove is formed, so that the air flow flowing between the bellows and the cylinder is controlled. The accumulated hydraulic fluid can not be passed over the circumferential groove until it leaks to the outside along with the air flow, but can be collected in the reservoir chamber via the groove, preventing oil droplets from scattering, and maintenance and peripheral equipment scattering. There is an advantage that the hydraulic auto tensioner is excellent in preventing deterioration due to oil.

  In addition, by arranging the circumferential groove formed in the cylindrical body on the surface where the bellows contacts along the thick edge provided on the edge of the bellows, oil droplets can be efficiently recovered from this circumferential groove or its vicinity. Thus, a hydraulic auto tensioner that exhibits the above advantages more reliably can be obtained.

  In addition, by forming the circumferential groove in the upper part of the cylinder and forming the lower part of the cylinder in a smaller diameter than the upper part, the hydraulic oil can be efficiently recovered from the groove extending in the cylinder length direction on the outer circumferential surface of the cylinder. There are advantages.

  Further, if a groove extending along the cylinder length direction is provided inside the cylindrical body contact surface of the bellows, the bellows can be ventilated only by being slightly elastically deformed along the groove, so that there is an advantage that displacement of the bellows is prevented. .

  Further, by arranging the bellows groove and the cylindrical groove so as to face each other and overlap each other, there is an advantage that a large collective groove is formed and a hydraulic auto tensioner that does not accumulate oil droplets more reliably is obtained.

Embodiments of the present invention will be described below with reference to the accompanying 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 tension pulley 3 urges the belt 4 to press the belt 4 by the hydraulic auto tensioner 10.

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

  As shown in FIG. 2, the hydraulic auto tensioner 10 has a cylinder 11 made of an aluminum alloy or the like. The cylinder 11 has a closed end at a lower portion, and a connecting piece 12 that is swingably connected to the pulley arm 1 is provided at the closed end.

  A sleeve fitting hole 13 is formed at the center of the inner bottom surface of the cylinder 11, and a steel bottomed sleeve 14 is fitted into the sleeve fitting hole 13. The sleeve 14 is fixed by caulking the inner peripheral portion of the inner bottom surface of the cylinder 11 and is prevented from coming out of the sleeve fitting hole 13.

  A piston 17 provided at the lower end of the rod 16 is slidably inserted into the sleeve 14, and a pressure chamber 18 is formed in the sleeve 14 by incorporating the piston 17. A retaining ring 19 for preventing the piston 17 from coming off is attached in the opening at the top of the sleeve 14.

  A seal ring 20 that elastically contacts the inner diameter surface of the sleeve 14 is attached to the outer periphery of the piston 17, and the sliding surface between the piston 17 and the sleeve 14 is sealed by the seal ring 20.

  A spring seat 21 is attached to the upper end portion of the rod 16 located outside the cylinder 11, and the return spring 22 incorporated between the spring seat 21 and the inner bottom surface of the cylinder 11 has the cylinder 11 and the rod 16 relative to each other. The cylinder 11 and the rod 16 are urged in a direction extending in the direction.

  As shown in FIG. 2, a connecting piece 26 that is swingably connected to the engine block is provided on the upper end surface of the spring seat 21. A cylindrical body 27 that covers the upper end of the return spring 22 is formed on the spring seat 21, and one end of an extendable bellows 28 is connected to the outer peripheral surface of the cylindrical body 27. The other end of the bellows 28 is connected to the upper outer periphery of the cylinder 11.

  As shown in an enlarged view in FIG. 3, a plurality of grooves 24 extending in the cylinder length direction are formed on the outer peripheral surface of the cylindrical body 27, and the circumferential grooves 25 that are connected to all the upper end portions of the grooves 24 in an intersecting manner. Forming. The circumferential groove 25 is disposed on the upper outer peripheral surface of the cylindrical body 27 with which the bellows 28 contacts, and is provided along a position close to the thick edge portion 28a fitted in the circumferential groove 27a.

  As shown in FIGS. 3 and 4, the grooves 24 extending in the longitudinal direction of the cylinder 27 are distributed on the outer peripheral surface of the cylinder 27 at equal angular intervals in the circumferential direction, and FIG. 4 shows the distribution of 12 grooves. The number of grooves is not limited, and one or more grooves may be formed. It is preferable to form at least 4 grooves, preferably 8 or more, in order to efficiently collect the hydraulic oil.

  The cylindrical body 27 is preferably cylindrical in shape, and in particular, the lower diameter dimension is smaller than the upper diameter dimension. If the lower portion of the cylindrical body 27 is formed with a small diameter, a gap is easily generated even with a low-pressure air flow between the bellows 28. If the groove 24 is formed in this portion, the hydraulic oil in the opened groove 24 is removed. It is easy to naturally flow or naturally fall into the reservoir chamber 29, which is advantageous for collecting the hydraulic oil.

  For the same reason, it is preferable to provide a groove 28b extending along the cylinder length direction also inside the contact surface of the bellows 28 with the cylinder 27. Further, when the auto tensioner is contracted, a relatively low pressure air flow can be vented from the groove 28b to the outside, and no large air pressure is applied to the connecting portion of the bellows 28, thereby preventing displacement in the axial direction and around the axis. be able to.

  As shown in FIGS. 3 and 4, four sets of grooves 28 b extending along the cylinder length direction and grooves 24 on the outer peripheral surface of the cylinder 27 are arranged inside the bellows 28 so that the groove openings face each other. ing. It is preferable that there are at least one set of collecting grooves combined in this way, and the number of sets is not particularly limited, but a collecting groove having a volume larger than that of one groove has a relatively low pressure and is gentle. Since the air flow is easy to flow, there is no gap between the cylindrical body 27 and the bellows 28 in the portion other than the collecting groove, and oil droplets can be prevented from collecting in other portions.

  As shown in FIG. 2, by attaching the bellows 28, a sealed reservoir chamber 29 is formed between the outer periphery of the sleeve 14 and the rod 16 and the inner peripheral surface of the cylinder 11, and the reservoir chamber 29 and the pressure chamber 18 are formed. Each is filled with hydraulic oil, and an air reservoir 30 is provided on the oil level of the hydraulic oil in the reservoir chamber 29.

  The reservoir chamber 29 and the pressure chamber 18 communicate with each other through a first passage 31 formed between the fitting surfaces of the sleeve fitting hole 13 and the sleeve 14, and the first passage 31 has a first portion at the end on the pressure chamber 18 side. The check valve 32 is provided.

  The first check valve 32 closes the first passage 31 and prevents the hydraulic oil in the pressure chamber 18 from flowing into the reservoir chamber 29 when the pressure in the pressure chamber 18 becomes higher than the pressure in the reservoir chamber 29. It has become.

  A second passage 33 extending in the axial direction is formed in the rod 16, and a throttle portion 34 formed of an orifice is provided at the lower end portion of the second passage 33. In order to facilitate the formation of the throttle portion 34, a recess 35 is formed in the lower end surface of the rod 16, and a throttle member 36 having an orifice formed in the recess 35 is press-fitted.

  The spring seat 21 is formed with a communication hole 37 that communicates the upper part of the second passage 33 and the upper part of the reservoir chamber 29 and a valve mounting hole 38 that communicates with the communication hole 37 from the side surface of the spring seat 21. The hole 37 is divided into an inlet portion 37 a and an outlet portion 37 b by a valve mounting hole 38. A solenoid valve unit 39 is connected to the valve mounting hole 38.

  The solenoid valve unit 39 has a valve housing 40, and the valve housing 40 is provided with a connecting cylinder 41 that is fitted into the valve mounting hole 38.

  Seal rings 42 are attached to the outer periphery of the front end portion and the rear end portion of the connection cylinder 41, and each seal ring 42 is in elastic contact with the inner diameter surface of the valve attachment hole 38 so that the valve attachment hole 38 and the connection cylinder 41 are connected to each other. Seals between mating surfaces.

  An oil passage hole 43 that communicates the inside of the connection tube 41 with the outlet portion 37 b of the communication hole 37 is formed at the tip of the connection tube 41.

  As shown in FIG. 2, the second check valve 44 is provided so as to be movable forward and backward with respect to a valve hole 47 formed in the valve seat 46 press-fitted into the distal end portion of the connection cylinder 41, and faces the valve seat 46. It comprises a rod 49 that holds a spherical valve body 48 at its distal end surface, and a spring 50 that urges the rod 49 toward the valve seat 46.

  The second check valve 44 opens the valve hole 47 when the pressure at the inlet 37a of the communication hole 37 is higher than the pressure at the outlet 37b. The rod 49 in the second check valve 44 is locked in a state where the valve body 48 closes the valve hole 47 by energizing the electromagnet 45.

  The hydraulic auto tensioner of the embodiment has the above-described structure. When the engine 5 and the auxiliary machine 7 are driven by the motor / generator 6 shown in FIG. 5, the electromagnet 45 shown in FIG. During normal driving by driving, the energization to the electromagnet 45 is cut off.

  Now, when the electromagnet 45 is de-energized, the second check valve 44 is unlocked. At this time, the belt tension changes due to the load fluctuation of the auxiliary machine 7, and the tension of the belt 4 increases to push up the cylinder 11. A force is applied to increase the pressure in the pressure chamber 18, and the first check valve 32 closes the first passage 31.

  For this reason, the hydraulic oil in the pressure chamber 18 does not flow from the first passage 31 to the reservoir chamber 29 but flows into the second passage 33 from the throttle portion 34. Since the flow resistance of the hydraulic oil in the throttle portion 34 is large, the hydraulic oil does not flow smoothly into the second passage 33, and the above-mentioned pushing force is buffered by the hydraulic oil sealed in the pressure chamber 18.

  When the push-up force is higher than the pressing force of the return spring 22, the hydraulic oil in the pressure chamber 18 flows from the throttle portion 34 to the second passage 33 and flows into the inlet portion 37 a of the communication hole 37, and the pressure of the hydraulic oil As a result, the valve body 48 of the second check valve 44 moves rightward in FIG. 2 to open the valve hole 47.

  Therefore, the hydraulic oil that has flowed into the second passage 33 flows from the oil passage hole 43 to the outlet portion 37b of the communication hole 37, and from the outlet portion 37b to the reservoir chamber 29. The cylinder 11 and the rod 16 contract relatively slowly until the pressure 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 16 by the pressing force of the return spring 22, and the pulley arm 1 swings by the movement, and the tension pulley 3 is pressed against the belt 4. The slack of the belt 4 is absorbed.

  When the cylinder 11 moves relative to the rod 16 in the extending direction, the pressure in the pressure chamber 18 decreases and becomes lower than the pressure in the reservoir chamber 29, so the first check valve 32 is opened.

  For this reason, the hydraulic oil in the reservoir chamber 29 flows into the pressure chamber 18 from the first passage 31, and the cylinder 11 moves smoothly in the extending direction to immediately absorb the slack of the belt 4.

  In the above embodiment, the lock type with the solenoid valve unit 39 is shown. However, in place of the solenoid valve unit 39, oil that communicates the inlet 37a and the outlet 37b of the communication hole 37 with the valve mounting hole 38 is shown. A non-locking hydraulic auto tensioner can be configured by attaching a flanged plug (not shown) in which a passage is formed.

Front view showing usage of hydraulic auto tensioner Front view of longitudinal section of hydraulic auto tensioner showing embodiment Sectional drawing of a partially cut-away view showing the connection between the bellows cylinder and cylinder Sectional view taken along line IV-IV in FIG. 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 (A) Longitudinal section front view of hydraulic auto tensioner showing conventional example, (b) Sectional view showing enlarged main part of (a)

Explanation of symbols

10 Hydraulic auto tensioner 11 Cylinder 14 Sleeve 16 Rod 17 Piston 18 Pressure chamber 21 Spring seat 22 Return spring 24 Groove 25 Circumferential groove 27 Cylindrical body 27a Peripheral groove 28 Bellows 28a Thick edge 28b Groove 29 Reservoir chamber 30 Air reservoir 31 First 1 passage 32 check valve 33 second passage 34 restricting portion 39 solenoid valve unit

Claims (5)

A sleeve is provided in a cylinder whose lower end is closed, and a piston provided at the lower end of the rod is slidably inserted into the sleeve to form a pressure chamber below the piston, and a spring seat provided at the upper part of the rod. A return spring that urges the cylinder and the rod in the direction of extending the cylinder and the rod is incorporated between the inner bottom surface of the cylinder and a cylinder covering the upper end of the return spring is provided integrally with the spring seat, and the outer periphery of the cylinder A reservoir chamber sealed between the cylinder and the sleeve and the rod is formed by connecting the surface and the outer peripheral upper portion of the cylinder with a bellows, and a first passage communicating the lower portion of the reservoir chamber and the lower portion of the pressure chamber A check valve that closes the passage when the pressure in the pressure chamber becomes higher than the pressure in the reservoir chamber, Other in hydraulic auto-tensioner having a second passage for through the gap of the piston and sleeve to flow hydraulic fluid in the pressure chamber to the reservoir chamber side,
One or more grooves extending in the cylinder length direction are formed on the outer peripheral surface of the cylindrical body, and a peripheral groove intersecting with the grooves is formed.   2. The hydraulic auto tensioner according to claim 1, wherein the circumferential groove formed in the cylindrical body is disposed on a surface where the bellows contacts along a thick edge provided at an end edge of the bellows.   The hydraulic auto tensioner according to claim 1 or 2, wherein a circumferential groove is formed in an upper part of the cylinder, and a lower part of the cylinder is formed to have a smaller diameter than the upper part.   The hydraulic auto tensioner according to any one of claims 1 to 3, wherein a groove extending along a cylinder length direction is provided on a cylinder contact surface inside the bellows.   The groove | channel extended along a cylinder length direction on the cylinder contact surface inside a bellows, and the groove | channel extended in a cylinder length direction on the outer peripheral surface of a cylinder are arrange | positioned so that one or more sets may be opposed. Hydraulic auto tensioner.

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