JP2006207614A - Tension adjusting device for belt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tension adjusting device for a belt capable of absorbing misalignment caused when assembling a hydraulic auto tensioner and suppressing reduction of function and durability of the hydraulic auto tensioner. <P>SOLUTION: This tension adjusting device for the belt is constituted by providing a tension pulley 3 on a pulley arm 1 supported on an engine A and capable of swinging, connecting one end part of the hydraulic auto tensioner 20 for energizing the pulley arm 1 in the direction for pressing the belt B with the pulley arm 1, and connecting the other end part with a connection piece 8 attached to the engine A. Spherical face-like sliding faces 7a, 27, 10, 33 having the center on a central shaft of the hydraulic auto tensioner 20 are provided in a connection part of the hydraulic auto tensioner 20 and the pulley arm 1 and a connection part of the hydraulic auto tensioner 20 and the connection piece 8, respectively, to absorb misalignment when mounting the hydraulic auto tensioner 20 by sliding in contact parts of the spherical face-like sliding faces 7a, 27, 10, 33 and prevent eccentric load applied to the hydraulic auto tensioner 20. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention mainly relates to a belt tension adjusting device for driving an automobile auxiliary machine such as an alternator.

  A pulley arm that supports the tension pulley is swingably attached to the engine, and the belt tension on the outer periphery of the tension pulley is absorbed by a hydraulic auto tensioner connected to the pulley arm so that the belt tension is kept constant. A belt tension adjusting device is described in Patent Document 1.

Here, the hydraulic auto tensioner seals the upper opening of a cylinder filled with hydraulic oil with a sealing member such as an oil seal, and applies a pressing force of a return spring to a rod that slidably passes through the sealing member. An outward projecting property is imparted, and the pushing force applied to the rod from the belt via the pulley arm is buffered by a hydraulic damper incorporated in the cylinder.
Japanese Patent Laid-Open No. 10-299846

  By the way, in the conventional belt tension adjusting device, a connecting piece is provided on each of the upper end of the rod of the hydraulic auto tensioner and the lower end of the cylinder, and a bearing fitting hole penetrating the both sides is formed in the connecting piece. The bolt is inserted into the cylindrical slide bearing fitted in the bearing fitting hole, the rod side connecting piece is connected to the pulley arm by tightening each bolt, and the cylinder side connecting piece is connected to the engine. Therefore, the hydraulic auto tensioner is easily affected by the accuracy of the engine arm mounting surface and the tensioner mounting surface. Here, if the surface accuracy of the mounting surface is poor, a misalignment occurs in which an inclination occurs between the pulley arm and the hydraulic auto tensioner, and an offset load is applied to the hydraulic auto tensioner, causing the relative relationship between the rod and the cylinder. The mechanical expansion and contraction is hindered, impairing the function of the hydraulic auto tensioner and reducing the durability.

  Further, uneven wear is likely to occur at the contact portion between the sliding bearing and the bearing fitting hole due to the uneven load applied to the hydraulic auto tensioner.

  For this reason, high-precision processing is required for the arm mounting surface and the tensioner mounting surface of the engine, and there is a disadvantage that processing takes time and processing cost increases.

  Also, hydraulic auto tensioners are usually mounted outside the engine cover, so if muddy water or the like is applied, the muddy water can easily enter the contact portion between the slide bearing and the bearing fitting hole. There is a problem that the remarkably decreases.

  An object of the present invention is to adjust the tension of a belt that can absorb a misalignment at the time of mounting a hydraulic auto tensioner and suppress a decrease in the function and durability of the hydraulic auto tensioner. Is to provide a device.

  In order to solve the above-mentioned problems, in the present invention, one end is connected to a swingable pulley arm that supports a tension pulley, and the other end is swingably connected to a fulcrum member on the engine side. In the belt tension adjusting device that absorbs a change in the tension of the belt passed over the tension pulley by the auto tensioner and keeps the tension of the belt constant, contact at the connecting portion of the hydraulic auto tensioner and the pulley arm and a hydraulic type The contact at the connecting portion between the auto tensioner and the fulcrum member is a spherical contact between a convex spherical sliding surface centered on the central axis of the hydraulic auto tensioner and a concave spherical sliding surface. .

  Here, as a hydraulic auto tensioner, a cylinder filled with hydraulic oil, a seal member that seals the upper end opening of the cylinder, a rod that slidably passes through the seal member, and an outward direction to the rod A return spring that imparts a projecting property of the cylinder, and a hydraulic damper that is incorporated in the cylinder and cushions the pushing force applied to the rod, and has a convex spherical slip at the lower end of the cylinder and the upper end of the rod. It is possible to employ a construction in which one of a surface and a concave spherical sliding surface is provided.

  In the adoption of the spherical sliding surface, the concave spherical sliding surface is positioned on the convex spherical sliding surface, so that muddy water is brought into contact with the concave spherical sliding surface and the convex spherical sliding surface. Intrusion can be prevented, and a decrease in durability of the connecting portion can be suppressed.

  In addition, when the concave spherical sliding surface is formed of a self-lubricating film, sliding at the contact portion between the concave spherical sliding surface and the convex spherical sliding surface can be performed smoothly.

  As described above, by providing a convex spherical sliding surface and a concave spherical sliding surface in surface contact with the connecting portion of the hydraulic auto tensioner to the engine and the pulley arm, the hydraulic pressure is increased when the hydraulic auto tensioner is mounted. When misalignment such as tilting of the automatic tensioner occurs, slip occurs at the contact portion between the convex spherical sliding surface and the concave spherical sliding surface to absorb the misalignment. For this reason, an unbalanced load does not act on the hydraulic auto tensioner, and a decrease in the function and durability of the hydraulic auto tensioner can be suppressed.

  Further, since it is possible to prevent an uneven load from acting on the connecting portion between the hydraulic auto tensioner and the engine, the durability of the connecting portion can be improved.

  Further, accuracy is not required for attachment to the engine, the attachment surface can be easily processed, and the processing cost can be reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 and 2 show a belt tension adjusting apparatus according to a first embodiment of the present invention. As shown in the drawing, the pulley arm 1 is supported at its upper end by a fulcrum shaft 2 screwed into the engine A, and is swingable about the fulcrum shaft 2.

  A tension pulley 3 is rotatably supported at a lower end portion which is a swing side end portion of the pulley arm 1. The pulley arm 1 has a pressure receiving piece 4 at the end on the swing center side, a support piece 5 is provided on the top surface of the tip of the pressure receiving piece 4, and a mounting bolt 6 to be screwed into the support piece 5 is tightened. Thus, the tensioner connector 7 provided on the distal end portion of the pressure receiving piece portion 4 is fixed. The tensioner connector 7 has a convex spherical sliding surface 7a on the outer periphery.

  A connecting piece 8 as a fulcrum member is provided above the pressure receiving piece 4. The connecting piece 8 is fixed to the engine A by tightening a bolt 9 screwed into the engine A, and a concave spherical sliding surface 10 is provided on the lower surface. The concave spherical sliding surface 10 is formed by a film 11 having self-lubricating properties.

  Between the connecting piece 8 and the pressure receiving piece 4 provided therebelow is provided a hydraulic auto tensioner 20 that urges the pulley arm 1 in the direction in which the tension pulley 3 presses the belt B.

  The hydraulic auto tensioner 20 includes a cylinder 21 filled with hydraulic oil, a seal member 22 that seals the upper opening of the cylinder 21, a rod 23 that slidably passes through the seal member 22, and an outward direction to the rod 23. And a hydraulic damper 25 that buffers the pushing force when a pushing force in a contracting direction is applied to the rod 23 and the cylinder 21.

  The cylinder 21 is made of an aluminum alloy, and a steel bottomed sleeve 26 is fitted therein. The cylinder 21 has a concave spherical sliding surface 27 centered on the central axis of the hydraulic auto tensioner 20 at the lower end, and the concave spherical sliding surface 27 is covered with a coating 28 having self-lubricating properties. Is formed. The concave spherical sliding surface 27 is in surface contact over a half circle or more of the spherical sliding surface 7a of the tensioner connector 7.

  The rod 23 has a spring seat 29 at its upper end, and a return spring 24 is assembled between the spring seat 29 and a spring seat 30 provided on the outer periphery of the lower end of the cylinder 21.

  A cylindrical cover 31 is provided on the lower surface of the spring seat 29 provided on the rod 23, and the cover 31 covers the upper outer periphery of the cylinder 21 to prevent dust and muddy water from entering the cylinder 21. Further, a hemispherical protrusion 32 is provided on the upper surface of the spring seat 29, and a convex spherical sliding surface 33 having a center on the central axis of the hydraulic auto tensioner 20 is formed on the outer periphery of the protrusion 32. ing. The convex spherical sliding surface 33 is in surface contact with the concave spherical sliding surface 10 provided on the lower surface of the connecting piece 8.

  The hydraulic damper 25 is connected to a lower end portion of the rod 23 with a plunger 34 slidable along the inner surface of the sleeve 26, and the plunger 34 partitions the inside of the cylinder 21 into a pressure chamber 35 and a reservoir chamber 36. Is provided with a passage 37 communicating with the lower pressure chamber 35 and the upper reservoir chamber 36, and a check valve 38 is provided at the opening of the passage 37 on the pressure chamber 35 side so that the rod 23 and the cylinder 21 are contracted. When a pushing force in a direction is applied, the passage 37 is closed by the check valve 38, and the pushing force is buffered by the hydraulic oil sealed in the pressure chamber 35.

  Reference numeral 39 denotes a spring that presses the plunger 34 against the lower end of the rod 23.

  The belt tension adjusting device shown in the embodiment has the above-described structure. When the belt B vibrates due to torque fluctuation or the like and the belt B is slackened, the cylinder 21 is lowered by the pressing force of the return spring 24 and the pulley arm. 1 is pressed. Therefore, the pulley arm 1 swings about the fulcrum shaft 2 and the tension pulley 3 presses the belt B to absorb the slack of the belt B.

  At this time, the volume of the pressure chamber 35 expands and the pressure decreases, and the check valve 38 opens the passage 37. Therefore, the hydraulic oil in the reservoir chamber 36 flows into the pressure chamber 35 from the passage 37, and the cylinder 21 is smooth. The belt B is moved downward to absorb the slack of the belt B immediately.

  On the other hand, when the tension of the belt B increases, a pushing force is applied from the belt B to the cylinder 21 via the tension pulley 3 and the pulley arm 1.

  At this time, since the pressure in the pressure chamber 35 becomes higher than the pressure in the reservoir chamber 36, the check valve 38 closes the passage 37 and the pushing force is buffered by the hydraulic oil sealed in the pressure chamber 35.

  When the pushing force is stronger than the elastic force of the return spring 24, the hydraulic oil in the pressure chamber 35 flows into the reservoir chamber 36 from a minute leak gap formed between the sliding surface of the sleeve 26 and the plunger 34, and the cylinder 21. Rises slowly to a position where the elastic force and the pushing force of the return spring 24 are balanced.

  When the hydraulic auto tensioner 20 is assembled, the hydraulic auto tensioner 20 is easily affected by the surface accuracy of the arm mounting surface and the piece mounting surface of the engine A. Misalignment occurs in which an inclination occurs between the tensioner 20, the pulley arm 1, and the connecting piece 8.

  At this time, the connecting portion between the pulley arm 1 and the cylinder 21 is a spherical contact between the convex spherical sliding surface 7 a of the tensioner connector 7 and the concave spherical sliding surface 27 of the cylinder 21, and the rod 23 and the connecting piece 8. In this connection portion, since the spherical contact surface of the concave spherical slide surface 10 of the connection piece 8 and the convex spherical slide surface 33 of the protrusion 32 is spherical contact, each misalignment occurs in the assembly of the hydraulic auto tensioner 20. Slip occurs at the contact portion of the spherical sliding surface to absorb the misalignment.

  For this reason, an unbalanced load does not act on the hydraulic auto tensioner 20, and the hydraulic auto tensioner 20 can be functioned with high accuracy and a decrease in durability can be suppressed.

  Further, since misalignment can be absorbed in the connecting portion between the pulley arm 1 and the cylinder 21 and the connecting portion between the rod 23 and the connecting piece 8, accuracy is not required for the piece mounting surface and the arm mounting surface of the engine A. For this reason, the mounting surface can be easily processed, and the processing cost can be reduced.

  Furthermore, the concave spherical sliding surfaces 27 and 10 and the convex spherical sliding surfaces 7a and 33 provided at the connecting portion between the cylinder 21 and the pulley arm 1 and the connecting portion between the rod 23 and the connecting piece 8 are convex. Since the concave spherical sliding surfaces 27, 10 are positioned on the spherical sliding surfaces 7a, 33 and cover the upper outer periphery of the convex spherical sliding surfaces 7a, 33, the spherical sliding surfaces 7a, 27 and 27 It is difficult for muddy water or the like to enter the contact portions 10 and 33, and a decrease in durability of each connecting portion can be suppressed.

  In the first embodiment, the lower end portion of the cylinder 21 is connected to the pulley arm 1 provided below the cylinder 21, and the upper end portion of the rod 23 is connected to the connection piece 8 provided thereabove. 3 and FIG. 4, the upper end portion of the rod 23 is connected to the pulley arm 1 provided above the rod 23, and the lower end portion of the cylinder 21 is connected to the support pin 40 as a fulcrum member provided therebelow. Thus, the tension of the belt B applied to the upper periphery of the tension pulley 3 may be kept constant.

  In this case, the lower end of the pulley arm 1 is supported by the fulcrum shaft 2 so as to be swingable, and is recessed on the lower surface of the tip end of the pressure receiving piece 4 projecting sideways from one end of the swing center. A spherical sliding surface 41 is formed, and a convex spherical sliding surface 33 of the protrusion 32 provided at the upper end of the rod 23 is brought into surface contact with the spherical sliding surface 41.

  Further, the support pin 40 is screwed to the engine A, a convex spherical sliding surface 42 is provided at the tip of the support pin 40, and the spherical sliding surface 42 is provided at the lower end of the cylinder 21. The concave spherical sliding surface 27 is brought into surface contact.

  Also in the second embodiment shown in FIG. 3 and FIG. 4, sliding at the contact portion between the concave spherical sliding surface 41 and the convex spherical sliding surface 33 and the concave spherical sliding surface 27 and the convex shape. Misalignment that occurs when the hydraulic auto tensioner 20 is assembled can be absorbed by slipping at the contact portion of the spherical sliding surface 42.

Partially cutaway front view showing a first embodiment of a belt tension adjusting device according to the present invention. 1 is a longitudinal side view of FIG. Partially cutaway front view showing a belt tension adjusting device according to a second embodiment of the present invention. Vertical side view of FIG.

Explanation of symbols

A Engine B Belt 1 Pulley arm 3 Tension pulley 7a Convex spherical sliding surface 8 Connection piece (fulcrum member)
DESCRIPTION OF SYMBOLS 10 Concave spherical sliding surface 20 Hydraulic auto tensioner 21 Cylinder 22 Seal member 23 Rod 24 Return spring 25 Hydraulic damper 27 Concave spherical sliding surface 33 Convex spherical sliding surface 40 Support pin (fulcrum member)
41 Concave spherical sliding surface 42 Convex spherical sliding surface

Claims (4)

  One end is connected to the swingable pulley arm that supports the tension pulley, and the other end is swingably connected to the fulcrum member on the engine side. In the belt tension adjusting device that absorbs and keeps the belt tension constant, the contact at the connecting portion between the hydraulic auto tensioner and the pulley arm and the contact at the connecting portion between the hydraulic auto tensioner and the fulcrum member are hydraulic. A belt tension adjusting device comprising a spherical contact surface between a convex spherical sliding surface and a concave spherical sliding surface centered on a central axis of an auto tensioner.   The hydraulic auto tensioner includes a cylinder filled with hydraulic oil, a seal member that seals the upper end opening of the cylinder, a rod that slidably passes through the seal member, and a protruding outward from the rod. A return spring for imparting a property and a hydraulic damper for buffering a pushing force applied to the rod by being incorporated in the cylinder, and a convex spherical sliding surface on the lower end of the cylinder and the upper end of the rod; 2. The belt tension adjusting device according to claim 1, wherein one of the concave spherical sliding surfaces is provided.   The belt tension according to claim 1 or 2, wherein the concave spherical sliding surface is positioned on the convex spherical sliding surface in the convex spherical sliding surface and the concave spherical sliding surface in surface contact therewith. Adjustment device.   4. The belt tension adjusting device according to claim 1, wherein the concave spherical sliding surface is made of a self-lubricating film.

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