JP5897969B2 - Hydraulic auto tensioner - Google Patents

Description

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

  In the belt transmission device for transmitting the rotation of the crankshaft of the engine to various automobile auxiliary machines, as shown in FIG. 7, a pulley arm 43 that can swing around a fulcrum shaft 42 is provided on the slack side of the belt 41. The adjustment force of the hydraulic auto tensioner A is applied to the pulley arm 43 to urge the pulley arm 43 in a direction in which the tension pulley 44 supported on the swing side end of the pulley arm 43 presses the belt 41, Is kept constant.

  As a hydraulic auto tensioner A used in the belt transmission as described above, the lower end of a rod is inserted into a cylinder filled with hydraulic oil, and the elastic force of a return spring is applied to the rod to the outside. It has been known that the above-described projecting property is imparted and the rod is buffered by a hydraulic damper provided inside the cylinder when a pushing force is applied to the rod.

  In the adoption of the hydraulic auto tensioner as described above, a connecting piece is provided on each of the lower closed end of the cylinder and the upper end of the rod located outside from the upper end of the cylinder, and the connecting piece on the cylinder side can swing freely on the engine block. The rod side connecting piece is connected to the pulley arm 43 shown in FIG.

  By the way, in the assembled state of the hydraulic auto tensioner, the cylinder side connecting piece and the rod side connecting piece are displaced in the axial direction of the connecting shaft perpendicular to the axis of the hydraulic auto tensioner, so that the hydraulic auto tensioner A There are many cases where tilt occurs.

  In this case, the cylinder and the rod cannot be expanded and contracted relatively smoothly, and the function of the hydraulic auto tensioner cannot be fully exhibited. In order to eliminate such inconvenience, in the hydraulic auto tensioner described in Patent Document 1, a bush is provided in a mounting hole formed in each of the cylinder side connecting piece and the rod side connecting piece, and an elastic ring is provided on the outside thereof. And a curved surface is provided on one of the outer diameter surface of the elastic ring and the inner diameter surface of the mounting hole so that the elastic ring and the bush supported by the elastic ring can be freely adjusted. The inclination error of the automatic tensioner is absorbed.

JP-A-9-170447

  By the way, in the hydraulic auto tensioner described in the above-mentioned Patent Document 1, in order to prevent the elastic ring from being removed and to make the support adjustable, the both ends of the outer surface of the elastic ring are directed radially outward. A pair of flanges are provided, and axial play is formed between the flanges and both side surfaces of the connecting piece. At this time, since the outer diameter of the flange is larger than the inner diameter of the mounting hole formed in the connecting piece, the flange obstructs the assembly of the elastic ring.

  In addition, an annular groove is formed on the outer diameter surface of the bush, and an annular ridge provided on the inner diameter surface of the elastic ring is engaged with the annular groove so as to couple the bush and the elastic ring. There is an inconvenience that it takes time and effort to fit the annular bulge portion with respect to the assembly.

  An object of the present invention is to improve the assemblability of a hydraulic auto tensioner that can absorb an inclination error in an assembled state to a belt transmission.

  In order to solve the above-described problems, in the present invention, a cylinder filled with hydraulic oil, a rod inserted into the cylinder, and the rod and the cylinder are urged toward a relatively extending direction. A return spring, and a hydraulic damper mechanism for buffering a pushing force when the rod is pushed in the axial direction against the elasticity of the return spring. Further, a connecting piece is provided at each of the upper end portions located outside the cylinder of the rod, a support ring is incorporated in a mounting hole formed in each of the connecting pieces, a bush is incorporated in the support ring, and the support One of the outer diameter surface of the ring and the inner diameter surface of the mounting hole is a curved surface, and the other is a cylindrical surface. In the tensioner, a flange for forming an axial clearance between the one end portion of the support ring and the other end portion of the bush and facing the radially outward side between the side surfaces of the connecting piece is provided. A configuration was adopted in which coupling means were provided between them to engage with each other by inserting a bush into the support ring so as not to be separated in the axial direction.

  In the hydraulic auto tensioner having the above-described configuration, when the support ring and the bush are assembled, the support ring is inserted from one side of the mounting hole formed in the connecting piece and from the other side of the mounting hole. A bush is inserted into the support ring. The coupling means is engaged by the insertion, and the support ring and the bush are coupled in the state of being inserted into the mounting hole to be assembled.

  In the assembled state, the outer peripheral portion of the flange formed on the support ring and the bush is opposed to the side surface of the connecting piece in the axial direction, so that the coupling part of the support ring and the bush is retained. Further, the coupling component is a support that can be adjusted in the mounting hole of the coupling piece.

  When the hydraulic auto tensioner having the above-described configuration is employed in the tension adjusting device for an auxiliary machine driving belt shown in FIG. 7, the cylinder-side connecting piece and the rod-side connecting piece are incorporated in the bushes incorporated in the mounting holes. A bolt is inserted, the cylinder side connecting piece is connected to the engine block by tightening the bolt, and the rod side connecting piece is connected to the pulley arm.

  In the assembled state as described above, the cylinder side connecting piece and the rod side connecting piece are displaced in the axial direction of the connecting shaft (bolt) perpendicular to the axis of the hydraulic auto tensioner, and the hydraulic auto tensioner A is inclined. When this occurs, the tilting error is absorbed by the aligning action of the support ring / bushing connecting part and the connecting piece rotating relatively, and the relative expansion and contraction of the cylinder and the rod is hindered. There is nothing.

  In the hydraulic auto tensioner according to the present invention, the bush and the support ring can be easily formed by reducing the cost by using the bush as the aluminum molded product and the support ring as the synthetic resin molded product. Can do. Further, the durability of the support ring can be improved as compared with the case where the support ring is formed of an elastic body.

  Polyamide 66 (PA66) or polyamide 46 (PA46) can be used as the synthetic resin as the material for forming the support ring, and in order to improve its durability, it is reinforced with glass fiber or carbon fiber. preferable.

  The coupling means for non-separating the support ring and the bush in the axial direction is to form a pair of ring grooves that are radially opposed to the inner diameter surface of the support ring and the outer diameter surface of the bush, and straddle the pair of ring grooves. Or a connecting ring that is elastically deformable in the radial direction, or an annular engagement groove formed at one end of the outer diameter surface of the bush and one end of the inner diameter surface of the support ring. And a projecting portion engaged with the engaging groove, and a tapered guide surface may be provided at the intersection of the one end surface of the bush and the outer diameter surface. .

  In employing the coupling means using the coupling ring, the coupling ring may be a snap ring with a part of the circumferential direction cut off, or may be an O-ring made of rubber. When a snap ring is used, the entire depth of the snap ring elastically deformed can be accommodated by setting one groove depth of the pair of opposed ring grooves to be equal to or greater than the outer diameter of the wire of the snap ring.

  In the present invention, as described above, the support ring is inserted from one side of the mounting hole formed in the connecting piece, and the bush is inserted from the other side of the mounting hole to the inside of the support ring. As a result, the coupling means engages and the support ring and the bush are assembled, so that the support ring and the bush can be assembled very easily, and a hydraulic auto tensioner with excellent assemblability is obtained. Can do.

Partially cutaway front view showing an embodiment of a hydraulic auto tensioner according to the present invention Sectional drawing which expands and shows the rod side connection piece of FIG. Sectional view along line III-III in FIG. (a) And (b) is sectional drawing which shows the connection state of a support ring and a bush in steps Sectional drawing which shows the other example of a support ring Sectional drawing which shows the other example of a coupling | bonding means 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 hydraulic auto tensioner has a cylinder 1, a rod 2 having a lower end inserted into the cylinder 1, and a return spring 3.

  The cylinder 1 is closed at the bottom and is filled with hydraulic oil. The return spring 3 is disposed outside the cylinder 1, and both ends are supported by a flange 4 formed on the outer periphery of the lower portion of the cylinder 1 and a spring seat 5 provided on the upper portion of the rod 2. It is energized in a relatively extending direction.

  The return spring 3 may be incorporated inside the cylinder 1.

  A hydraulic damper mechanism 6 is incorporated in the cylinder 1 to buffer the pushing force when the pushing force is applied to the rod 2. As the hydraulic damper mechanism 6, here, a slidable plunger 9 is provided inside the cylinder 1 to partition the inside of the cylinder 1 into a pressure chamber 7 and a reservoir chamber 8, and the pressure chamber 7 and the reservoir chamber are provided in the plunger 9. 8 is formed, and a check valve 11 is provided at the opening of the passage 10 on the pressure chamber 7 side. The rod 2 is pushed in so that the pressure in the pressure chamber 7 is higher than the pressure in the reservoir chamber 8. When this happens, the check valve 11 is closed so that the pushing force applied to the rod 2 by the hydraulic oil in the pressure chamber 7 is buffered.

  The hydraulic damper mechanism 6 is not limited to the structure described above.

  A connecting piece 12 is provided on the lower surface of the cylinder 1, and a connecting piece 13 is also provided on the spring seat 5 provided on the top of the rod 2.

  Each of the connecting pieces 12 and 13 is formed with mounting holes 14 and 15 penetrating through both side surfaces, and the internal structures of the mounting holes 14 and 15 are the same. As for the internal configuration of the cylinder side connecting piece 12, the same reference numerals are given to the same parts as the internal configuration of the rod side connecting piece 13, and the description thereof is omitted.

  As shown in FIGS. 2 and 3, the mounting hole 15 formed in the connecting piece 13 has a curved surface 16 having a convex arcuate cross section.

  A support ring 17 is installed inside the mounting hole 15, and a bush 18 is incorporated inside the support ring 17. A length of the support ring 17 in the axial direction is longer than a width dimension between both side surfaces of the connecting piece 13, and a flange 19 facing radially outward is formed on the outer periphery of one end located outside the attachment hole 15.

  On the other hand, the axial length of the bush 18 is longer than the axial length of the support ring 17, and a radially outwardly facing flange 20 is formed on the outer periphery of the other end located outside from the other end of the bush 18. Yes.

  The outer diameters of the flanges 19 and 20 are larger than the inner diameters at both ends of the mounting hole 15, the outer peripheral portion faces both side surfaces of the connecting piece 13, and an axial clearance X is formed between the opposing portions. Yes.

  The outer diameter surface of the support ring 17 is a cylindrical surface 21, which is in contact with the inner diameter surface of the mounting hole 15 at the central portion in the axial direction, or is opposed with a minute gap and reaches the both ends. Y gradually increases, and the support ring 17 can be adjusted within the range of the radial clearance Y and the axial clearance X.

  The support ring 17 is a synthetic resin molded product, while the bush 18 is an aluminum molded product. A coupling means 30 is provided between the support ring 17 and the bush 18 so as to be engaged by inserting the bush 18 into the support ring 17 so as not to be separated in the axial direction.

  The coupling means 30 forms a pair of ring grooves 31 and 32 that are radially opposed to the inner diameter surface of the support ring 17 and the outer diameter surface of the bush 18, and extends in a radial direction so as to straddle the pair of ring grooves 31 and 32. The support ring 17 and the bush 18 are not separated in the axial direction by incorporating a connecting ring 33 that can be elastically deformed.

  Here, a snap ring from which a part in the circumferential direction is cut is used as the connection ring 33, but an O-ring made of rubber may be used as the connection ring 33. When a snap ring is used as the connection ring 33, the connection is made by reducing the groove depth of the ring groove 32 formed on the outer diameter surface of the bush 18 to a depth equal to or greater than the wire diameter of the connection ring 33. The entire ring 33 can be accommodated, and on the other hand, the groove depth of the ring groove 31 formed on the inner periphery of the support ring 17 is approximately ½ of the wire diameter of the connecting ring 33.

  Contrary to the above, the entire connection ring 33 in which the groove depth of the ring groove 31 formed in the inner periphery of the support ring 17 is expanded to a depth equal to or greater than the diameter of the wire rod of the connection ring 33. On the other hand, the groove depth of the ring groove 32 formed on the outer diameter surface of the bush 18 can be about ½ of the wire diameter of the connecting ring 33.

  The hydraulic auto tensioner shown in the embodiment has the above-described structure. When the support ring 17 and the bush 18 are assembled, the hydraulic auto tensioner is supported from one side of the mounting holes 14 and 15 formed in the connecting pieces 12 and 13. While inserting the ring 17, the bush 18 is inserted into the support ring 17 from the other side of the mounting holes 14, 15, and the support ring 17 and the bush 18 are pushed into each other and moved relative to each other.

  4A and 4B show the coupling state of the support ring 17 and the bush 18 step by step. At the time of the coupling, as shown in FIG. 4A, a connecting ring 33 is fitted in a ring groove 32 formed on the outer diameter surface of the bush 18.

  When the connecting ring 33 is fitted into the ring groove 32, the support ring 17 and the bush 18 are pushed into each other, so that the front end surface of the supporting ring 17 abuts the connecting ring 33 in the middle of the relative movement. The connecting ring 33 is pressed. By the pressing, the connecting ring 33 is reduced in diameter and accommodated in the ring groove 32 of the bush 18.

  As shown in FIG. 4B, the support ring 17 and the bush 18 are further moved relative to each other from the state in which the connecting ring 33 is accommodated in the ring groove 32, and the ring groove 31 of the support ring 17 and the ring groove 32 of the bush 18 are However, when opposed to each other in the radial direction, the connecting ring 33 is expanded in diameter by restoring elasticity and straddles the pair of opposed ring grooves 31, 32, and the support ring 17 and the bush 18 are combined and integrated, and the support ring 17 and the bush 18 is set in an assembled state.

  In the assembled state as described above, the outer peripheral portions of the flanges 19 and 20 formed on the support ring 17 and the bush 18 are opposed to the side surfaces of the connecting pieces 12 and 13 in the axial direction. Parts are secured. In addition, the coupling component is supported in a freely adjustable manner within the mounting holes 14 and 15 of the coupling pieces 12 and 13.

  As shown in FIG. 4A, if the tapered surface 34 is provided at the other end of the inner diameter surface of the support ring 17, the connecting ring 33 can be smoothly reduced in diameter.

  When the hydraulic auto tensioner having the above-described configuration is employed in the tension adjusting device for the accessory driving belt shown in FIG. 7, the mounting holes of the cylinder side connecting piece 12 and the rod side connecting piece 13 as shown in FIG. A bolt 35 is inserted into each of the bushes 18 incorporated in 14 and 15, and the cylinder side connecting piece 12 is fastened to the engine block B by tightening the bolt 35, and the rod side connecting piece 13 is connected to the pulley arm 43.

  When the cylinder-side connecting piece 12 and the rod-side connecting piece 13 are displaced in the axial direction of the bolt 35 and the hydraulic auto tensioner A is inclined in the assembled state as described above, the support ring 17 and the bush 18 are joined. The tilt error is absorbed by the aligning action in which the component and the connecting pieces 12 and 13 rotate relative to each other. For this reason, the relative expansion and contraction of the cylinder 1 and the rod 2 is not hindered, and the hydraulic auto tensioner functions accurately.

  In FIG. 2, the inner surface of the mounting hole 15 formed in the connecting piece 13 is a convex curved surface 16, the outer surface of the support ring 17 is a cylindrical surface 21, and the support ring 17 is a support that can be adjusted. As shown in FIG. 5, the inner diameter surface of the mounting hole 15 may be a cylindrical surface 22, and the outer diameter surface of the support ring 17 may be a curved surface 23 having a convex arc shape in cross section.

  In FIG. 2, as the coupling means 30, a connecting ring 33 is assembled so as to straddle a ring groove 31 formed on the inner diameter surface of the support ring 17 and a ring groove 32 formed on the outer diameter surface of the bush 18. However, the coupling means 30 is not limited to this.

  FIG. 6 shows another example of the coupling means 30. In this example, an annular engagement groove 36 is formed at one end portion of the outer diameter surface of the bush 18, and a protruding portion 37 provided at one end portion of the inner diameter surface of the support ring 17 is engaged with the engagement groove 36. I have to. In order to facilitate the engagement, a tapered guide surface 38 is provided at the intersection of one end surface of the bush 18 and the outer diameter surface.

  Here, the projecting portion 37 may be annular, or may be a plurality of protrusions provided at intervals in the circumferential direction.

DESCRIPTION OF SYMBOLS 1 Cylinder 2 Rod 3 Return spring 6 Hydraulic damper mechanism 12 Connection piece 13 Connection piece 14 Installation hole 15 Installation hole 16 Curved surface 17 Support ring 18 Bush 19 Flange 20 Flange 30 Connecting means 31 Ring groove 32 Ring groove 33 Connection ring 36 Engagement groove 37 Projection 38 Guide surface

Claims (6)

A cylinder filled with hydraulic oil; a rod inserted into the cylinder; and a return spring that urges the rod and the cylinder toward a relatively extending direction. A hydraulic damper mechanism that cushions the pushing force when the rod is pushed in the axial direction against the elasticity of the return spring is connected to each of the lower closed end of the cylinder and the upper end of the rod located outside the cylinder A support ring is incorporated in the mounting hole formed in each of the connecting pieces, and a bush is incorporated in the support ring, and either the outer diameter surface of the support ring or the inner diameter surface of the mounting hole In a hydraulic auto tensioner in which one is a curved surface and the other is a cylindrical surface, and the support ring is a support that can be freely adjusted,
A flange for forming an axial clearance between the one end of the support ring and the other end of the bush is formed between the support ring and the bush. A coupling means that engages by insertion of the bush into the support ring and is non-separated in the axial direction, and the coupling means faces the inner diameter surface of the support ring and the outer diameter surface of the bush in the radial direction. A hydraulic auto tensioner comprising a pair of ring grooves and a connecting ring that is elastically deformable in a radial direction so as to straddle the pair of ring grooves .   The hydraulic auto tensioner according to claim 1, wherein the bush is an aluminum molded product, and the support ring is a synthetic resin molded product.   The hydraulic auto tensioner according to claim 2, wherein the synthetic resin is made of polyamide or polyimide reinforced with glass fiber or carbon fiber. 4. The connection ring according to claim 1, wherein the connection ring includes a snap ring that is partially cut off in a circumferential direction, and one of the pair of opposed ring grooves has a groove depth that is equal to or greater than an outer diameter of a wire rod of the snap ring . The hydraulic auto tensioner according to any one of claims. The hydraulic auto tensioner according to any one of claims 1 to 3, wherein the connection ring is an O-ring made of rubber. A cylinder filled with hydraulic oil; a rod inserted into the cylinder; and a return spring that urges the rod and the cylinder toward a relatively extending direction. A hydraulic damper mechanism that cushions the pushing force when the rod is pushed in the axial direction against the elasticity of the return spring is connected to each of the lower closed end of the cylinder and the upper end of the rod located outside the cylinder A support ring is incorporated in the mounting hole formed in each of the connecting pieces, and a bush is incorporated in the support ring, and either the outer diameter surface of the support ring or the inner diameter surface of the mounting hole In a hydraulic auto tensioner in which one is a curved surface and the other is a cylindrical surface, and the support ring is a support that can be freely adjusted,
A flange for forming an axial clearance between the one end of the support ring and the other end of the bush is formed between the support ring and the bush. A coupling means that engages by inserting the bush into the support ring and is non-separated in the axial direction, and the coupling means includes an annular engagement groove formed at one end portion of the outer diameter surface of the bush; A projecting portion provided at one end of the inner diameter surface of the support ring and engaged with the engagement groove, and having a tapered guide surface at the intersection of the one end surface of the bush and the outer diameter surface A hydraulic auto tensioner characterized by

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