JP2007239908A - Hydraulic automatic tensioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydraulic automatic tensioner, in which a sleeve hard to fall off by vibration and impact in carrying. <P>SOLUTION: This hydraulic automatic tensioner is constituted so that a rod 7 is inserted into a bottomed cylinder 6; a return spring 10 is arranged for energizing its rod 7 outside the cylinder 6; a hydraulic damper 11 damping pushing-in force applied to the rod 7, is incorporated into the cylinder 6; and connecting pieces 20 and 26 are respectively arranged on the tip of the rod 7 and the blocking-up end of the cylinder 6. A pair of bushes 22 and 22 are axially pressed at an interval in a bush insertion hole 21 formed in the connecting piece 20, and a ring-shaped member 25 is incorporated between its pair of bushes 22 and 22. A metallic sleeve 24 is inserted into the bushes 22 and 22, and the ring-shaped member 25 is elastically contacted with the outer periphery of its sleeve 24. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a hydraulic auto tensioner used for adjusting the tension of a belt that drives an auxiliary machine such as an alternator.

  An auxiliary machine of an automobile, for example, an alternator, a car air conditioner, a water pump, or the like has a rotating shaft connected to a crankshaft of an engine by a belt, and is driven by the engine through the belt. In order to keep the tension of this belt within an appropriate range, generally, a tension pulley that contacts the belt, a swingable pulley arm that supports the tension pulley, one end connected to the pulley arm, and the other end connected to the engine block There is used a belt tension adjusting device that applies a tension to a belt by biasing a pulley arm with the hydraulic auto tensioner (Patent Document 1).

  As a hydraulic auto tensioner incorporated in this belt tension adjusting device, a rod is inserted into a bottomed cylinder, and a return spring is provided to urge the rod outward from the cylinder, thereby buffering the pushing force applied to the rod. A hydraulic auto tensioner in which a hydraulic damper mechanism is incorporated in a cylinder is known (Patent Document 2).

  In this hydraulic auto tensioner, the rod moves to the position where the urging force of the return spring and the belt tension are balanced to absorb the belt tension fluctuation, and the hydraulic damper incorporated in the cylinder is driven by the belt tension fluctuation. The pushing force applied to the rod is buffered to stabilize the belt tension.

  In addition, conventionally, a hydraulic auto tensioner is connected to an engine block by attaching a bush to a connecting piece provided at the closed end of a cylinder, inserting a metal sleeve into the bush, and connecting the sleeve with a bolt. It is fixed to the engine block. Similarly, the hydraulic auto tensioner is often connected to the pulley arm by attaching a bush to a connecting piece provided at the tip of the rod and fixing the sleeve inserted into the bush to the pulley arm with a bolt.

However, when the hydraulic auto tensioner is conveyed with the sleeve inserted in the bush, the sleeve is likely to drop off. For this reason, the sleeve cannot be assembled until just before it is assembled to the engine block, and handling such as transportation and storage is troublesome.
JP-A-10-19099 Japanese Patent Laid-Open No. 10-366860

  The problem to be solved by the present invention is to provide a hydraulic auto tensioner in which the sleeve does not easily fall off due to vibration or impact during conveyance.

  In order to solve the above-mentioned problem, a hydraulic damper mechanism is provided that inserts a rod into a bottomed cylinder, provides a return spring that urges the rod to the outside of the cylinder, and cushions the pushing force applied to the rod. In a hydraulic auto tensioner incorporated in the cylinder and provided with connecting pieces at the tip of the rod and the closed end of the cylinder, a pair of bushes are axially inserted into a bush insertion hole formed in at least one of the connecting pieces. Press-fitting at intervals, a ring-shaped member was assembled between the pair of bushes, a metal sleeve was inserted into the pair of bushes, and the ring-shaped member was brought into elastic contact with the outer periphery of the sleeves.

  This hydraulic auto tensioner is more preferable when a circumferentially continuous groove is formed on the outer periphery of the sleeve, and the ring-shaped member is elastically contacted with the inner surface of the groove.

  The above-described problem is that a bush is press-fitted into a bush insertion hole formed in at least one of the connecting pieces, a metal sleeve is inserted into the bush, and a groove formed continuously in the circumferential direction on the outer periphery of the sleeve. The problem can also be solved by incorporating a ring-shaped member into the inner ring and elastically contacting the ring-shaped member with the inner periphery of the bush.

  The ring-shaped member is preferably constituted by a circlip or an O-ring.

  The hydraulic auto tensioner according to the present invention in which a ring-shaped member incorporated between the pair of bushes is brought into elastic contact with the outer periphery of the sleeve allows the ring-shaped member to move in the axial direction by the pair of bushes press-fitted into the bush insertion holes. The axial movement of the sleeve is restricted by the elastic contact with the ring-shaped member. For this reason, the sleeve is unlikely to fall off the bush during conveyance of the hydraulic auto tensioner.

  Further, in the case where the ring-shaped member is elastically contacted with the inner surface of the groove formed on the outer periphery of the sleeve, the sleeve on the outer periphery of the sleeve restrains the ring-shaped member in the axial direction, so that the sleeve is further dropped. Hateful.

  Also, the hydraulic auto tensioner of the present invention in which a ring-shaped member incorporated in a groove formed on the outer periphery of the sleeve is elastically contacted with the inner periphery of the bush is a ring-shaped member by elastic contact with the inner periphery of the bush. The axial movement of the sleeve is restricted, and the axial movement of the sleeve is restricted by the restriction of the ring-shaped member. For this reason, the sleeve is unlikely to fall off the bush during conveyance of the hydraulic auto tensioner.

  Furthermore, what comprised the said ring-shaped member with the circlip or O-ring can obtain a ring-shaped member cheaply, and is economical.

  FIG. 1 shows a belt tension adjusting device for applying tension to a belt 1 for driving an automobile auxiliary machine. This belt tension adjusting device has a tension pulley 2 that contacts the belt 1 and a pulley arm 3 that rotatably supports the tension pulley 2, and the pulley arm 3 is a fulcrum shaft 4 that is fixed to an engine block (not shown). Is supported so as to be swingable around the center. One end of a hydraulic auto tensioner 5 according to an embodiment of the present invention is connected to the pulley arm 3, and the other end of the hydraulic auto tensioner 5 is connected to an engine block. The hydraulic auto tensioner 5 biases the pulley arm 3 in a direction in which the tension pulley 2 is pressed against the belt 1.

  As shown in FIG. 2, in the hydraulic auto tensioner 5, a rod 7 is inserted into a cylinder 6 having a bottom at the lower end, and a spring seat 8 is attached to the upper end of the rod 7. A flange portion 9 is formed on the outer periphery of the cylinder 6, and a return spring 10 that urges the rod 7 outward of the cylinder 6 is incorporated between the flange portion 9 and the spring seat 8. Further, a hydraulic damper mechanism 11 is incorporated in the cylinder 6 to buffer the pushing force applied to the rod 7 when the tension of the belt 1 increases.

  The hydraulic damper mechanism 11 has a plunger 12 connected to the lower end of the rod 7 and a sleeve 13 inserted and fixed in the cylinder 6. The plunger 12 is slidably inserted into a sleeve 13 filled with hydraulic oil, and divides the inside of the cylinder 6 into a pressure chamber 14 and a reservoir chamber 15. A plunger spring 16 that holds the plunger 12 against the rod 7 is incorporated in the pressure chamber 14.

  The pressure chamber 14 and the reservoir chamber 15 communicate with each other via a passage 17 formed in the plunger 12, and the opening on the pressure chamber 14 side of the passage 17 is operated from the reservoir chamber 15 side to the pressure chamber 14 side. A check valve 18 that allows only the flow of oil is provided.

  An oil seal 19 is attached to the upper portion of the cylinder 6 so that the rod 7 is slidably penetrated and the hydraulic oil is sealed in the cylinder 6.

  A connecting piece 20 is provided on the spring seat 8 at the upper end of the rod 7, and a pair of bushes 22, 22 are press-fitted at intervals in the axial direction into a bush insertion hole 21 formed through the connecting piece 20. Yes. As shown in FIG. 3, a flange portion 23 is formed at one end of each bush 22, and the flange portion 23 is engaged with the edge of the bush insertion hole 21 to position the bush 22 in the axial direction. A metal sleeve 24 is rotatably inserted into the bush 22, and a ring-shaped member 25 incorporated between the bushes 22 and 22 is in elastic contact with the outer periphery of the sleeve 24.

  Similarly, a connecting piece 26 is also provided at the closed end of the cylinder 6, and a pair of bushes 28, 28 similar to the bush 22 are spaced apart in the axial direction in a bush insertion hole 27 formed through the connecting piece 26. It is press-fitted after. A metal sleeve 29 is rotatably inserted into the bushes 28 and 28, and a ring-shaped member 30 incorporated between the bushes 28 and 28 is in elastic contact with the outer periphery of the sleeve 29.

  The hydraulic auto tensioner 5 is connected to the pulley arm 3 by inserting a bolt 31 into the sleeve 24 and fixing the sleeve 24 to the pulley arm 3 by tightening the bolt 31 to connect the hydraulic auto tensioner 5 to the engine block. The connection is performed by inserting a bolt 32 into the sleeve 29 and fixing the sleeve 29 to the engine block by tightening the bolt 32.

  The operation of the belt tension adjusting device incorporating this hydraulic auto tensioner 5 will be described.

  When the tension of the belt 1 becomes small, the rod 7 moves to the outside of the cylinder 6 to a position where the tension of the belt 1 and the biasing force of the return spring 10 are balanced, and the pulley arm 3 swings by the movement, and the belt 1 is slackened. Absorb. At this time, since the pressure in the pressure chamber 14 becomes lower than the pressure in the reservoir chamber 15, the check valve 18 is opened, and the hydraulic oil in the reservoir chamber 15 flows through the passage 17 into the pressure chamber 14. Therefore, the tension pulley 2 moves quickly, and the slack of the belt 1 is absorbed quickly.

  On the other hand, when the tension of the belt 1 increases, the rod 7 is pushed inward of the cylinder 6 to a position where the tension of the belt 1 and the biasing force of the return spring 10 are balanced. Absorb tension. At this time, since the pressure in the pressure chamber 14 becomes higher than the pressure in the reservoir chamber 15, the check valve 18 is closed, and the hydraulic oil in the pressure chamber 14 forms a leak gap formed between the sliding surfaces of the plunger 12 and the sleeve 13. And flows to the reservoir chamber 15. Therefore, the pushing force applied to the rod 7 is buffered, and the tension pulley 2 moves slowly, absorbing the tension while keeping the belt 1 in a stable state.

  In the hydraulic auto tensioner 5, the axial movement of the ring-shaped member 25 is restricted by the bushes 22, 22 press-fitted into the bush insertion hole 21, and the axial movement of the sleeve 24 is caused by elastic contact with the ring-shaped member 25. Since it is regulated, the sleeve 24 is unlikely to fall off the bush 22 due to vibration or impact during conveyance. Therefore, handling such as transportation and storage is easy. Similarly, the sleeve 29 is also difficult to drop off from the bush 28.

  In the above embodiment, the sleeves 24 and 29 are incorporated in the connecting pieces 20 and 26, respectively. However, the sleeve is incorporated in only one of the connecting pieces 20 and 26, and the sleeve is prevented from being detached by the ring-shaped member having the above-described configuration. May be. Alternatively, the sleeves 24 and 29 may be incorporated in the connecting pieces 20 and 26, respectively, and only one of the sleeves 24 and 29 may be prevented from being detached by the ring-shaped member having the above-described configuration. In short, a pair of bushes may be press-fitted into the bush insertion hole of at least one of the connecting pieces at an interval in the axial direction, and the sleeve inserted into the pair of bushes may be prevented from coming off with the ring-shaped member having the above-described configuration.

  In the above embodiment, the sleeve 24 is formed so that the outer diameter is constant, and the ring-shaped member 25 is elastically contacted with the outer periphery of the sleeve 24. However, a circumferentially continuous groove is formed on the outer periphery of the sleeve. Preferably, the ring-shaped member is elastically brought into contact with the inner surface of the groove. That is, as shown in FIG. 4, bushes 33 and 33 similar to the bush 22 are press-fitted into the bush insertion hole 21, a ring-shaped member 34 is assembled between the bushes 33 and 33, and the sleeve is inserted into the bushes 33 and 33. The ring-shaped member 34 may be brought into elastic contact with the inner surface of the outer circumferential groove 36. If it does in this way, since the groove | channel 36 restrains the ring-shaped member 34 to an axial direction, the sleeve 35 becomes more difficult to drop off. The sleeve 29 is also preferably formed with a similar groove on the outer periphery.

  In the above embodiment, the ring-shaped member 25 incorporated between the pair of bushes 22 and 22 is brought into elastic contact with the outer periphery of the sleeve 24 to prevent the sleeve 24 from coming off. However, as shown in FIG. A groove 38 continuous in the circumferential direction may be formed on the outer periphery of the ring 37, and the ring-shaped member 39 incorporated in the groove 38 may be brought into elastic contact with the inner periphery of the bush 40 press-fitted into the bush insertion hole 21. Even in this case, the axial movement of the ring-shaped member 39 is restricted by the elastic contact with the inner periphery of the bush 40, and the axial movement of the sleeve 37 is restricted by the restriction of the ring-shaped member 39. The sleeve 37 is difficult to fall off.

  The ring-shaped members 25, 30, 34, and 39 are preferably constituted by a circlip such as a C-shaped concentric snap ring or a rubber O-ring. In this way, the ring-shaped members 25, 30, 34, and 39 can be obtained at low cost, which is economical.

Front view showing a belt tension adjusting device incorporating a hydraulic auto tensioner according to an embodiment of the present invention. Cross section of the hydraulic auto tensioner shown in FIG. Enlarged sectional view of the connecting piece of the hydraulic auto tensioner shown in FIG. FIG. 2 is an enlarged sectional view of a connecting piece showing a modification of the hydraulic auto tensioner of FIG. The expanded sectional view of the connection piece which shows the other modification of the hydraulic auto tensioner of FIG.

Explanation of symbols

6 Cylinder 7 Rod 10 Return spring 11 Hydraulic damper mechanism 20, 26 Connecting piece 21 Bushing insertion hole 22 Bushing 24 Sleeve 25 Ring-like member 27 Bushing insertion hole 28 Bushing 29 Sleeve 30 Ring-like member 33 Bushing 34 Ring-like member 35 Sleeve 36 Groove 37 Sleeve 38 Groove 39 Ring-shaped member 40 Bush

Claims (4)

  A rod 7 is inserted into the bottomed cylinder 6, a return spring 10 is provided for urging the rod 7 outward of the cylinder 6, and a hydraulic damper mechanism 11 for buffering the pushing force applied to the rod 7 is provided in the cylinder. 6, in a hydraulic auto tensioner in which connecting pieces 20 and 26 are provided at the tip of the rod 7 and the closed end of the cylinder 6, respectively, a pair of bushing insertion holes 21 formed in at least one of the connecting pieces 20 are paired. The bushes 22, 22 are press-fitted at intervals in the axial direction, a ring-shaped member 25 is assembled between the pair of bushes 22, 22, and a metal sleeve 24 is inserted into the pair of bushes 22, 22. A hydraulic auto tensioner, wherein the ring-shaped member 25 is brought into elastic contact with the outer periphery of the sleeve 24.   The hydraulic auto tensioner according to claim 1, wherein a groove that is continuous in a circumferential direction is formed on an outer periphery of the sleeve, and the ring-shaped member is elastically contacted with an inner surface of the groove.   A rod 7 is inserted into the bottomed cylinder 6, a return spring 10 is provided for urging the rod 7 outward of the cylinder 6, and a hydraulic damper mechanism 11 for buffering the pushing force applied to the rod 7 is provided in the cylinder. 6, in a hydraulic auto tensioner provided with connecting pieces 20 and 26 at the tip of the rod 7 and the closed end of the cylinder 6, a bush is inserted into a bush insertion hole 21 formed in at least one of the connecting pieces 20. 40 is press-fitted, a metal sleeve 37 is inserted into the bush 40, and a ring-shaped member 39 is incorporated into a groove 38 formed continuously in the circumferential direction on the outer periphery of the sleeve 37. A hydraulic auto tensioner characterized in that it is brought into elastic contact with the inner periphery of the bush 40.   The hydraulic auto tensioner according to any one of claims 1 to 3, wherein the ring-shaped member is a circlip or an O-ring.

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