JP2014101955A - Hydraulic auto tensioner for auxiliary machinery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic auto tensioner for auxiliary machinery in which debris such as press-fit burr or the like generated at the time of assembly of a sleeve can be prevented from mixing into hydraulic fluid within a pressure chamber.SOLUTION: A reservoir chamber 14 is formed between a cylinder 1 and a sleeve 4, an oil passage 15 communicating between the reservoir chamber 14 and a pressure chamber 6 is arranged between fitting surfaces of the sleeve 4 and a sleeve fitting hole 3, and then a check valve 17 closed when a pressure within the pressure chamber 6 becomes higher than that in the reservoir chamber 14 is assembled in the lower end part of the sleeve 4. A filter 30 is assembled at the hydraulic fluid flowing-in side of a valve hole formed at a valve seat 18 of a check valve 17. When the hydraulic fluid in the reservoir chamber 14 passes from the oil passage 15 into the valve hole through the filter 30, the hydraulic fluid is filtered with the filter 30 to collect the debris mixed in the hydraulic fluid and the debris is prevented from entering into the pressure chamber 6.

Description

  The present invention relates to a hydraulic auto tensioner used for tension adjustment of an auxiliary machine driving belt for driving an auxiliary machine such as an alternator, a water pump, and a compressor of an air conditioner.

  As shown in FIG. 9, a pulley arm 53 that can swing around a shaft 52 is provided on the slack side of the belt 51 in a belt transmission device that transmits the rotation of the crankshaft of an engine to various automobile auxiliary machines such as an alternator. Then, the adjusting force of the hydraulic auto tensioner A is applied to the pulley arm 53 to urge the pulley arm 53 in a direction in which the rotatable tension pulley 54 supported by the swinging end of the pulley arm 53 presses the belt 51. The tension of the belt 51 is kept constant.

  As an auxiliary machine hydraulic auto tensioner A used for the belt transmission as described above, the one described in Patent Document 1 has been conventionally known. In this hydraulic auto-tensioner for auxiliary machinery, a pressure chamber is formed in the sleeve by slidably inserting the lower part of the rod into a sleeve standing from the bottom of the bottomed cylinder in which the hydraulic oil is accommodated. A return spring is incorporated between a spring seat provided at the top of the cylinder and the bottom surface of the cylinder to urge the rod and the cylinder in the extending direction.

  In addition, a cylindrical spring cover that covers the upper part of the return spring is provided at the lower part of the spring seat, and the inner periphery of the seal member incorporated in the upper opening of the cylinder is brought into elastic contact with the outer periphery of the spring cover so that the cylinder and the sleeve are in contact. A sealed reservoir chamber is formed, and the reservoir chamber and the pressure chamber are communicated by an oil passage formed at the bottom of the cylinder. The pressure chamber and the oil are closed to the lower end opening of the sleeve when the pressure in the pressure chamber rises. It incorporates a check valve that shuts off passage communication.

  The hydraulic auto tensioner configured as described above connects the connecting piece provided on the lower surface of the cylinder to the engine block so as to be rotatable, and connects the connecting piece provided on the upper surface of the spring seat to the pulley arm 53 shown in FIG. When a pressing force is applied from the belt 51 through the tension pulley 54 and the pulley arm 53 in the direction of contracting the cylinder and the rod, the check valve is closed, and the hydraulic oil sealed in the pressure chamber is passed between the sleeve and the rod. The fluid is caused to flow through a leak gap formed between the sliding surfaces, and a hydraulic damper force is generated in the pressure chamber by the viscous resistance of the hydraulic oil at the time of the flow to buffer the pushing force.

JP 2009-275757 A

  By the way, in the hydraulic auto tensioner described in Patent Document 1, a sleeve fitting hole is formed on the bottom surface of the cylinder, and the lower end portion of the sleeve is press-fitted into the sleeve fitting hole to maintain the assembled state. Therefore, the allowance due to press-fitting is relatively large, and when the sleeve is press-fitted, the sleeve is press-fitted while squeezing the sleeve fitting hole, and the press-fitting burrs are formed on the outer peripheral portion of the lower end surface of the sleeve. There is a possibility.

  At this time, in the hydraulic type auto tensioner, the lower end surface of the sleeve is positioned above the lower surface of the valve seat of the check valve incorporated in the lower end portion of the sleeve, and the sleeve has the lower end surface and the bottom surface of the sleeve fitting hole. Because of the assembly with a gap formed between them, if the burr generated at the time of press-fitting drops, it flows into the oil passage from the gap, enters the hydraulic oil in the pressure chamber, floats, and is loaded on the hydraulic auto tensioner When the pressing force is buffered, the damper function may be hindered by biting into a leak gap or a check valve.

  An object of the present invention is to provide a hydraulic auto tensioner for an auxiliary machine that can prevent foreign matter such as a press-fitting burr generated at the time of assembling a sleeve from being mixed into hydraulic oil in a pressure chamber. is there.

  In order to solve the above-described problems, in the present invention, a sleeve fitting hole is formed in the bottom upper surface of a bottomed cylinder in which hydraulic oil is stored, and an oil reservoir is provided on the bottom surface of the sleeve fitting hole. The lower end of the sleeve is press-fitted into the fitting hole, the lower end of the rod is slidably inserted into the sleeve, a pressure chamber is formed inside the sleeve, and a spring seat and cylinder provided on the upper portion of the rod A return spring is assembled between the upper surfaces of the bottoms of the cylinders to urge the cylinders and rods in the extending direction, and a cylindrical spring cover is provided on the spring seat to cover the top of the return springs. The inner periphery of the seal member is elastically contacted with the outer periphery of the spring cover to form a reservoir chamber between the cylinder and the sleeve, and the fitting surface of the sleeve and the sleeve fitting hole An oil passage that communicates the reservoir chamber and the pressure chamber via the oil reservoir, and closes in the lower end portion of the sleeve when the pressure in the pressure chamber becomes higher than the pressure in the reservoir chamber, and the pressure chamber communicates with the oil passage. In a hydraulic auto-tensioner for auxiliary equipment that incorporates a check valve that shuts off the pressure, the foreign matter in the hydraulic oil flowing into the valve hole is trapped on the hydraulic oil inflow side of the valve hole formed in the check valve. The structure provided with the filter which prevents flowing in into the room was adopted.

  As described above, by providing the filter on the hydraulic oil inflow side of the valve hole formed in the check valve, the rod and sleeve are extended by the pressing force of the return spring, the check valve is opened, and the hydraulic oil in the reservoir chamber is released. It is filtered when it flows from the oil passage to the oil sump and passes through the filter. If foreign matter is mixed in the hydraulic oil by the filtration, the foreign matter is captured by the filter.

  For this reason, even if burrs are generated and mixed into the hydraulic oil when the sleeve is assembled by press fitting into the sleeve fitting hole, the burrs are captured by the filter. Therefore, there is no inconvenience that foreign matters such as burrs flow into the pressure chamber and bite into the leak gap or the check valve to hinder the damper function, and the hydraulic damper can function reliably.

  Here, the filter may be made of a net, or may be made of a porous metal called a porous metal or a foam metal.

  When a mesh filter is used, if the mesh size is less than 0.1 mm, the flow resistance of the hydraulic oil increases, and the hydraulic oil does not flow smoothly from the reservoir chamber to the pressure chamber, preventing the rod and sleeve from extending. In addition, if it exceeds 0.2 mm, burrs and the like generated when the sleeve is press-fitted cannot be captured. Therefore, it is preferable to employ a net having a mesh size of 0.1 mm to 0.2 mm.

  The net may be a flat net that covers the lower surface of the valve seat of the check valve and is sandwiched between the lower surface of the valve seat or the lower surface of the sleeve and the bottom surface of the sleeve fitting hole. And a cup-shaped member having a flange sandwiched between the lower surface of the valve seat of the check valve or the lower surface of the sleeve and the bottom surface of the sleeve fitting hole on the outer periphery of the open end.

  On the other hand, when a porous metal is employed as a filter, the porosity should be in the range of 90 to 97% in consideration of fluidity of hydraulic oil and trapping ability of foreign matter.

  The filter made of porous metal may be in the form of a sheet sandwiched between the lower surface of the valve seat of the check valve or the lower surface of the sleeve and the bottom surface of the sleeve fitting hole, or a circle accommodated in an oil reservoir. It may consist of columnar blocks.

  In the present invention, as described above, by providing the filter on the hydraulic oil inflow side of the valve hole formed in the check valve, the hydraulic oil in the reservoir chamber passes from the oil reservoir through the filter to the valve hole of the check valve. When flowing in, foreign matter mixed in the hydraulic oil can be captured by the filter. Therefore, foreign matter can be prevented from flowing into the pressure chamber, and there is no inconvenience that the damper function is hindered by the biting of the foreign matter, and the hydraulic damper can be reliably functioned.

A longitudinal sectional view showing an embodiment of an auxiliary hydraulic auto tensioner according to the present invention Sectional drawing which expands and shows a part of FIG. Sectional view of cylinder cut along line III-III in FIG. A longitudinal sectional view showing another example of the hydraulic auto tensioner for auxiliary machines according to the present invention Sectional drawing which shows the other example of a filter Sectional drawing which shows the other example of a filter Sectional drawing which shows the other example of a filter Sectional view of the relief valve assembly Front view showing a tension adjusting device for an auxiliary machine driving belt

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, the cylinder 1 has a bottom portion, and a connecting piece 2 connected to the engine block is provided on the bottom surface of the bottom portion. The cylinder 1 is made of an aluminum alloy and is formed by die casting. When the non-porous die casting method (PF die casting method) is adopted for the die casting, the cylinder 1 having excellent quality without a casting nest can be obtained.

  The connecting piece 2 is provided with a shaft insertion hole 2a penetrating from one side surface to the other side surface, a cylindrical fulcrum shaft 2b in the shaft insertion hole 2a, and a sliding bearing 2c for rotatably supporting the fulcrum shaft 2b. And the fulcrum shaft 2b is fixed by tightening a bolt that is inserted into the fulcrum shaft 2b and screwed into the engine block, and the cylinder 1 is pivotably mounted about the fulcrum shaft 2b. Is done.

  A sleeve fitting hole 3 is provided on the upper surface of the bottom of the cylinder 1, and a lower end portion of a steel sleeve 4 is press-fitted into the sleeve fitting hole 3. The lower portion of the rod 5 is slidably inserted into the sleeve 4, and the pressure chamber 6 is provided in the sleeve 4 by the insertion of the rod 5.

  A spring seat 7 is fixed to an upper end portion of the rod 5 located outside the cylinder 1, and a return spring 8 incorporated between the spring seat 7 and the bottom surface of the cylinder 1 extends relative to the cylinder 1 and the rod 5. It is energizing in the direction to

  A connecting piece 9 connected to the pulley arm 53 shown in FIG. 9 is provided at the upper end of the spring seat 7. The connecting piece 9 is formed with a sleeve insertion hole 9a penetrating from one side surface to the other side surface, and a sleeve 9b and a slide bearing 9c for rotatably supporting the sleeve 9b are incorporated in the sleeve insertion hole 9a. The connecting piece 9 is rotatably connected to the pulley arm 53 by a bolt inserted into the sleeve 9b.

  The spring seat 7 is formed of a molded product, and a cylindrical dust cover 10 that covers the upper outer periphery of the cylinder 1 and a cylindrical spring cover 11 that covers the upper portion of the return spring 8 are molded at the same time to form the spring seat 7. Is integrated.

  Here, the spring seat 7 may be a die-cast molded product of an aluminum alloy, or may be a molded product of a resin such as a thermosetting resin.

  The entire outer periphery of the spring cover 11 is covered with a cylindrical body 12 that is insert-molded when the spring seat 7 is molded. The cylinder 12 is made of a press-formed product of a steel plate.

  An oil seal 13 as a seal member is incorporated in the upper opening of the cylinder 1, and the inner periphery of the oil seal 13 is in elastic contact with the outer peripheral surface of the cylinder 12 to close the upper opening of the cylinder 1. This prevents the hydraulic oil contained in the inside from leaking to the outside and prevents dust from entering the inside.

  By incorporating the oil seal 13, a sealed reservoir chamber 14 is formed between the cylinder 1 and the sleeve 4. The reservoir chamber 14 and the pressure chamber 6 include an oil passage 15 formed between the fitting surfaces of the sleeve fitting hole 3 and the sleeve 4, and an oil sump 16 formed of a circular recess formed at the center of the bottom surface of the sleeve fitting hole 3. It communicates through.

  As shown in FIGS. 2 and 3, the oil passage 15 includes an axial groove 15a and a radial groove 15b extending radially inward from the lower end of the axial groove 15a and communicating with the oil reservoir 16. The upper opening 15c of the axial groove 15a has a long hole shape facing outward in the radial direction.

  There are a plurality of oil passages 15. In the embodiment, the four are arranged in a plane cross shape, and the oil passage 15 divides the bottom surface and the inner peripheral surface of the sleeve fitting hole 3 into four.

  As shown in FIG. 2, a check valve 17 is incorporated in the lower end portion of the sleeve 4. The check valve 17 includes a valve seat 18 having a valve hole 19, a check ball 20 that opens and closes the valve hole 19 of the valve seat 18 from the pressure chamber 6, and a valve retainer 21 that regulates the opening and closing amount of the check ball 20. The check ball 20 includes a valve spring 22 that urges the check ball 20 toward the valve hole 19.

  When the pressure in the pressure chamber 6 becomes higher than the pressure in the reservoir chamber 14, the check valve 17 closes the valve hole 19 to shut off the communication between the pressure chamber 6 and the oil passage 15, and the pressure chamber 6 is prevented from flowing into the reservoir chamber 14 through the oil passage 15.

  The check valve 17 is positioned in the axial direction by a positioning flange 23 provided at the inner peripheral lower portion of the sleeve 4, and the lower surface of the valve seat 18 is assembled below the lower end surface of the sleeve 4.

  A filter 30 is incorporated on the hydraulic oil inflow side of the valve hole 19 formed in the valve seat 18. Here, the filter 30 is made of a flat net made of SUS metal, and is supported by being sandwiched between the lower surface of the valve seat 18 and the bottom surface of the sleeve fitting hole 3.

  When the hydraulic oil in the reservoir chamber 14 flows from the oil reservoir 16 into the valve hole 19, the filter 30 filters the hydraulic oil to capture foreign substances and prevent the foreign substances from flowing into the pressure chamber 6. The mesh size is 0.1 mm to 0.2 mm.

  In FIG. 2, since the lower surface of the valve seat 18 is disposed below the lower end surface of the sleeve 4, the filter 30 is supported by the lower surface of the valve seat 18 and the bottom surface of the sleeve fitting hole 3. As shown in FIG. 4, when the lower end surface of the sleeve 4 is disposed below the lower surface of the valve seat 18, the filter 30 is supported by the lower end surface of the sleeve 4 and the bottom surface of the sleeve fitting hole 3. .

  The rod 5 is formed with a valve fitting hole 24 that opens at the lower end surface thereof, and a T-shaped oil passage 25 that communicates the upper portion of the valve fitting hole 24 with the reservoir chamber 14. A relief valve 40 is incorporated therein.

  As shown in FIG. 8, the relief valve 40 opens and closes the valve seat 41 press-fitted into the lower end opening of the valve fitting hole 24 and the valve hole 42 formed in the valve seat 41 from within the valve fitting hole 24. A spherical valve body 43, a spring seat 44 provided on the upper side of the valve body 43, and the valve body 43 is attached to the seat surface 45 formed on the upper surface of the valve seat 41 via the spring seat 44. The valve spring 46 is energized.

  Here, the spring seat 44 is circular and is slidable along the inner diameter surface of the valve fitting hole 24, and a gap is formed between the sliding surface of the spring seat 44 and the valve fitting hole 24. .

  Further, a rod 44a disposed in the valve spring 46 is integrally provided on the upper surface of the spring seat 44, and a conical recess 44b into which the upper portion of the valve body 43 is fitted is formed on the lower surface.

  The relief valve 40 configured as described above uses the elastic force of the valve spring 46 as a set pressure, and the valve body 45 opens the valve hole 42 when the pressure in the pressure chamber 6 exceeds the set pressure. .

  As shown in FIG. 1, the rod 5 is formed with a ring groove 26 at a lower end portion located in the sleeve 4, and a retaining ring 27 fitted into the ring groove 26 is formed at the upper inner periphery of the sleeve 4. The rod 5 is prevented from being pulled out by contact with the step portion 28.

  Here, the amount of the hydraulic oil contained in the cylinder 1 is 40 of the inner space volume in the most extended state in which the sleeve 4 and the rod 5 are relatively elongated and the retaining ring 27 is in contact with the step portion 28. % Or more.

  The hydraulic auto tensioner shown in the embodiment has the above-described configuration. When adjusting the tension of the accessory driving belt 51 shown in FIG. 9, the connecting piece 2 provided at the closed end of the cylinder 1 is connected to the engine block, In addition, the connecting piece 9 of the spring seat 7 is connected to the pulley arm 53 and an adjustment force is applied to the pulley arm 53.

  In the tension adjustment state of the belt 51 as described above, when the tension of the belt 51 changes due to a load variation of the auxiliary machine and the tension of the belt 51 becomes weak, the cylinder 1 and the rod 5 are expanded by the pressing of the return spring 8. Relative movement in the direction absorbs slackness of the belt 51.

  Here, when the cylinder 1 and the rod 5 move relative to each other in the extending direction, the pressure in the pressure chamber 6 becomes lower than the pressure in the reservoir chamber 14, so the check ball 20 of the check valve 17 opens the valve hole 19. . Therefore, the hydraulic oil in the reservoir chamber 14 flows smoothly from the valve hole 19 into the pressure chamber 6 through the oil passage 15, and the cylinder 1 and the rod 5 smoothly move relative to each other in the extending direction to loosen the belt 51. Absorb immediately.

  On the other hand, when the tension of the belt 51 is increased, a pushing force in a direction of contracting the cylinder 1 and the rod 5 of the hydraulic auto tensioner is applied from the belt 51. At this time, since the pressure in the pressure chamber 6 becomes higher than the pressure in the reservoir chamber 14, the check ball 20 of the check valve 17 closes the valve hole 19.

  Further, the hydraulic oil in the pressure chamber 6 flows into the leak gap 29 formed between the inner diameter surface of the sleeve 4 and the outer diameter surface of the rod 5 and flows into the reservoir chamber 14. A hydraulic damper force is generated in the pressure chamber 6 by the viscous resistance. The pushing force applied to the hydraulic auto tensioner is buffered by the hydraulic damper force, and the cylinder 1 and the rod 5 are slowly retracted in a direction in which the pushing force and the elastic force of the return spring 8 are balanced. Move relative.

  When the tension of the belt 51 is strong and the pressure in the pressure chamber 6 exceeds the set pressure of the relief valve 40, the valve body 43 of the relief valve 40 is opened, and the hydraulic oil in the pressure chamber 6 flows from the oil passage 25 into the reservoir chamber 14. The pressure in the pressure chamber 6 is maintained at the set pressure of the relief valve 40.

  The hydraulic auto tensioner shown in FIG. 1 has a configuration in which the lower end portion of the sleeve 4 is press-fitted into the sleeve fitting hole 3 to maintain the assembled state. At this time, the sleeve 4 is press-fitted while squeezing the sleeve fitting hole 3. During the press-fitting, burrs may be formed. Here, when the burr is dropped from the lower end surface of the sleeve 4 and mixed into the hydraulic oil and flows into the pressure chamber 6 in a floating state, the pressing force applied to the hydraulic auto tensioner is buffered as described above. There is a possibility that the damper function may be hindered by biting into the leak gap 29 or the check valve 17.

  In the embodiment, as shown in FIG. 2, since the filter 30 is provided on the hydraulic oil inflow side of the valve hole 19 formed in the valve seat 18 of the check valve 17, the rod 5 is pressed by the pressing force of the return spring 8. And the sleeve 4 is extended, the check valve 17 is opened, and the hydraulic oil in the reservoir chamber 14 flows from the oil passage 15 to the oil reservoir 16 and flows into the valve hole 19 through the filter 30. When the foreign matter is mixed in the hydraulic oil, the foreign matter is captured by the filter 30.

  For this reason, even if burrs are generated when the sleeve 4 is assembled by press-fitting into the sleeve fitting hole 3 and mixed into the hydraulic oil, the burrs are captured by the filter 30. Therefore, there is no inconvenience that foreign matter such as burrs flows into the pressure chamber 6 and bites into the leak gap 29 or the check valve to inhibit the damper function, and the hydraulic damper can be functioned reliably.

  In FIG. 2 and FIG. 4, the filter 30 is a flat mesh, but the shape of the filter 30 is not limited to a flat mesh. For example, as shown in FIG. 5, the cup is accommodated in the oil sump 16, and is sandwiched between the lower surface of the valve seat 18 or the lower end surface of the sleeve 4 in FIG. 4 and the bottom surface of the sleeve fitting hole 3. It may be provided with an outward flange 30a.

  Further, the filter 30 is not limited to a mesh. In FIG. 6 and FIG. 7, a porous metal having a porosity in the range of 90 to 97% is used as the filter 30. Here, FIG. 6 shows a sheet-like filter 30 sandwiched between the lower surface of the valve seat 18 and the bottom surface of the sleeve fitting hole 3, and FIG. 7 shows that the oil reservoir 16 is accommodated in the oil reservoir 16. The filter 30 which consists of a cylindrical block dedicated by the bottom face of this and the lower surface of the valve seat 18 is shown.

1 Cylinder 3 Sleeve fitting hole 4 Sleeve 5 Rod 6 Pressure chamber 7 Spring seat 8 Return spring 11 Spring cover 13 Oil seal (seal member)
14 Reservoir chamber 15 Oil passage 16 Oil reservoir 17 Check valve 18 Valve seat 19 Valve hole 30 Filter 30a Flange

Claims (7)

A sleeve fitting hole is formed in the bottom upper surface of the bottomed cylinder containing the hydraulic oil, an oil reservoir is provided on the bottom surface of the sleeve fitting hole, and the lower end of the sleeve is press-fitted into the sleeve fitting hole. The lower end of the rod is slidably inserted into the sleeve, a pressure chamber is formed inside the sleeve, and a return spring is assembled between the spring seat provided on the upper portion of the rod and the bottom upper surface of the cylinder, and the cylinder and rod The spring seat is provided with a cylindrical spring cover that covers the upper part of the return spring, and the inner periphery of the seal member incorporated in the upper opening of the cylinder is elastically contacted with the outer periphery of the spring cover. A reservoir chamber is formed between the cylinder and the sleeve, and the reservoir chamber and the pressure chamber are interposed between the fitting surfaces of the sleeve and the sleeve fitting hole via the oil reservoir. Hydraulic auto-tensioner for auxiliaries, provided with an oil passage that communicates, and a check valve that is closed when the pressure in the pressure chamber becomes higher than the pressure in the reservoir chamber and that blocks the communication between the pressure chamber and the oil passage in the lower end of the sleeve In
A filter is provided on the hydraulic oil inflow side of the valve hole formed in the check valve so as to capture foreign matters contained in the hydraulic oil flowing into the valve hole and prevent the foreign matter from flowing into the pressure chamber. Hydraulic auto tensioner for auxiliary machines.   The hydraulic auto tensioner for auxiliary machines according to claim 1, wherein the filter is made of a net having a mesh size of 0.1 mm to 0.2 mm.   3. The hydraulic type for an auxiliary machine according to claim 2, wherein the filter includes a flat net that covers a lower surface of the valve seat of the check valve and is sandwiched between the lower surface of the valve seat or the lower surface of the sleeve and the bottom surface of the sleeve fitting hole. Auto tensioner.   The filter is housed in the oil sump and has a cup shape having a flange sandwiched between a bottom surface of a valve seat of a check valve or a bottom surface of a sleeve and a bottom surface of a sleeve fitting hole on an outer periphery of an opening end. Item 3. The hydraulic auto tensioner for auxiliary equipment according to Item 2.   The hydraulic auto tensioner for auxiliary machines according to claim 1, wherein the filter is made of a porous metal having a porosity of 90 to 97%.   6. The hydraulic auto tensioner for an auxiliary machine according to claim 5, wherein the filter made of porous metal is formed into a sheet shape that is sandwiched between a lower surface of a valve seat of a check valve or a lower surface of a sleeve and a bottom surface of a sleeve fitting hole.   The hydraulic auto tensioner for auxiliary machines according to claim 5, wherein the filter made of porous metal is a cylindrical block accommodated in the oil reservoir.

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