JP2010180898A - Automatic tensioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an automatic tensioner capable of being installed tilting greatly relative to the vertical direction. <P>SOLUTION: In the automatic tensioner 5, a lower part of a sleeve 10 is fitted to a sleeve fitting recessed part 11 formed in an inner bottom surface 9 of a cylinder 8. The inside of the cylinder 8 is partitioned into a pressure chamber 13 and a reservoir chamber 14 by inserting a rod 12 slidably into the sleeve 10. An oil passageway 18 is provided for communicating the lower part of the pressure chamber 13 and the lower part of the reservoir chamber 14 with each other between the sleeve fitting recessed part 11 and a fitting surface of the sleeve 10. A check valve 19 is provided at an end of the pressure chamber 13 side of the oil passageway 18. A suction port 20 of a working fluid from the reservoir chamber 14 to the oil passageway 18 is opened in the inner bottom surface 9 of the cylinder 8. The suction port 20 is opened only on one region out of two divided regions in which the inner bottom surface 9 of the cylinder 8 is divided into two by a diameter. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an auto tensioner used for maintaining the tension of a belt for driving an automobile auxiliary machine such as an alternator.

  An auxiliary machine of an automobile, such as an alternator, a car air conditioner, or a water pump, has a rotating shaft connected to a crankshaft of an engine with a belt, and is driven via the belt. In order to keep the tension of this belt within an appropriate range, generally, a pulley arm that is swingable about a fulcrum shaft, a tension pulley that is rotatably attached to the pulley arm, and a direction in which the tension pulley is pressed against the belt. A tension adjusting device including an auto tensioner that biases the pulley arm is used.

  As shown in FIG. 12, as an auto tensioner 30 incorporated in this tension adjusting device, hydraulic oil is stored in a cylinder 31 having a bottom at the bottom, and a sleeve fitting recess 33 formed on an inner bottom surface 32 of the cylinder 31 is provided with a sleeve. 34, the rod 35 is slidably inserted into the sleeve 34, the cylinder 31 is partitioned into a pressure chamber 36 and a reservoir chamber 37, and the rod 35 is projected from the sleeve 34 by a return spring 38. (Patent Documents 1 and 2) are known.

  The auto tensioner 30 absorbs fluctuations in belt tension as the rod 35 moves to a position where the biasing force of the return spring 38 is balanced with the tension of the belt (not shown).

  The upper portion of the pressure chamber 36 and the upper portion of the reservoir chamber 37 communicate with each other via an annular throttle gap 39 formed between the sliding surface of the rod 35 and the sleeve 34, and the rod 35 is pushed into the cylinder 31. When moving in the direction (hereinafter referred to as “push-in direction”), the hydraulic oil in the pressure chamber 36 flows out through the throttle gap 39. At this time, a damper action is generated by the viscous resistance of the hydraulic oil flowing through the throttle gap 39, so that the rod 35 moves slowly.

  The lower portion of the pressure chamber 36 and the lower portion of the reservoir chamber 37 communicate with each other via an oil passage 40 provided between the fitting surface of the sleeve fitting recess 33 and the sleeve 34. A check valve 41 that allows only the flow of hydraulic oil from the reservoir chamber 37 side to the pressure chamber 36 side is provided at the end portion on the 36 side. Therefore, when the rod 35 moves in the direction in which it protrudes from the cylinder 31 (hereinafter referred to as “projection direction”), the check valve 41 is opened and hydraulic oil flows from the reservoir chamber 37 side to the pressure chamber 36 side. Move quickly.

  Here, as shown in FIG. 13, four oil passages 40 are provided between the fitting surfaces of the sleeve fitting recess 33 and the sleeve 34 at intervals in the circumferential direction. The hydraulic oil suction ports 42 of the respective oil passages 40 open to the inner bottom surface 32 of the cylinder 31 so as to be equally spaced in the circumferential direction.

Special Table 2000-504395 JP 2007-32713 A

  By the way, the auto tensioner 30 may be attached in a state of being inclined with respect to the vertical direction for convenience of the layout of the automobile auxiliary equipment. If this inclination angle can be set large, the layout of the automobile auxiliary equipment may be increased. The degree of freedom increases.

  However, as shown in FIG. 12, when the auto tensioner 30 is attached in a state of being largely inclined with respect to the vertical direction, the inner bottom surface 32 of the cylinder 31 is also inclined with respect to the horizontal direction. There is a possibility that the incoming suction port 42 is exposed from the oil level of the hydraulic oil in the reservoir chamber 37 and the air in the reservoir chamber 37 is sucked into the pressure chamber 36. If air is sucked into the pressure chamber 36, when the belt tension increases, the air in the pressure chamber 36 is compressed and the rod 35 moves, so that the damper action of the auto tensioner 30 is reduced. .

  The problem to be solved by the present invention is to provide an auto tensioner that can be attached in a state of being largely inclined with respect to the vertical direction.

  In order to solve the above problems, the working oil suction port from the reservoir chamber to the oil passage is opened only in one of the regions obtained by dividing the inner bottom surface of the cylinder into two by diameter. In this case, the suction port is made to be inclined from the oil level of the hydraulic oil in the reservoir chamber by tilting the auto tensioner with the region where the suction port is opened, of the region obtained by dividing the inner bottom surface of the cylinder into two by diameter. It is possible to prevent exposure.

  It is preferable that an annular washer for receiving the lower end of the return spring is airtightly fitted to the outer periphery of the sleeve, and the washer is overlapped on the inner bottom surface of the cylinder. In this case, since the washer covers the portion of the suction port along the outer periphery of the sleeve, the suction port opens below the case where no washer is provided, and as a result, the suction port is exposed from the oil surface. Can be reliably prevented.

  When the washer is overlapped on the inner bottom surface of the cylinder, an arc groove extending in an arc shape is formed on the inner bottom surface of the cylinder so as not to be blocked by the washer, and an area of the arc groove that is not blocked by the washer is formed. When the suction port is used, the opening area of the suction port is increased, and the suction resistance to the oil passage can be reduced. In this case, if the opening area of the suction port is set larger than the flow passage area of the oil passage, the suction resistance to the oil passage can be reliably reduced.

  When the arc groove is formed so that the radially inner portion thereof overlaps the washer, it is preferable that a convex portion protruding radially outward is provided on the radially inner edge of the arc groove. If it does in this way, since a washer can be received in the convex part, a bend of a washer by reaction force of a return spring can be prevented.

  As the washer, for example, a flat washer can be used. The flange portion of the washer may overlap the inner bottom surface of the cylinder. In this case, since the fitting length between the washer and the sleeve is long, the airtight reliability between the washer and the sleeve is high.

  A plurality of the oil passages can be provided at intervals in the circumferential direction. If it does in this way, channel resistance of an oil passage can be controlled. Further, even when one of the plurality of oil passages is clogged, the communication between the pressure chamber and the reservoir chamber can be ensured through the other oil passages. Reliability can be ensured.

  Preferably, the cylinder is provided with an identification mark indicating the circumferential position of the suction port. In this way, since the circumferential position of the suction port is known by the identification mark, it is difficult to make a mistake in the direction in which the auto tensioner is attached, and it is possible to prevent the auto tensioner from being inclined with the suction port facing upward. As such an identification mark, for example, a protrusion or a recess provided on the outer periphery of the cylinder so that the circumferential position of the suction port coincides with the suction port.

  An electromagnetic on-off valve that opens and closes the second oil passage by communicating the pressure chamber and the reservoir chamber via a second oil passage provided with a throttle that restricts the flow rate of the hydraulic oil can be provided. If it does in this way, the movement of the rod to a pushing direction can be prevented by closing an electromagnetic opening-and-closing valve. Therefore, when this auto tensioner is used in an engine that is driven and started by a motor generator connected to the belt, the belt is slipped when the engine is started by starting the engine with the electromagnetic on-off valve closed. It becomes possible to prevent.

  In the auto tensioner according to the present invention, since the suction port exists only in one of the regions obtained by dividing the inner bottom surface of the cylinder into two by the diameter, the suction port can be formed by inclining the auto tensioner with this region as a lower side. Can be prevented from being exposed from the oil level of the hydraulic oil in the reservoir chamber. Therefore, this auto tensioner can be attached in a state of being largely inclined with respect to the vertical direction, and the degree of freedom of layout of the automobile auxiliary equipment is high.

The front view which shows the tension adjustment apparatus incorporating the auto tensioner of embodiment of this invention 1 is an enlarged sectional view of the auto tensioner shown in FIG. FIG. 2 is an enlarged sectional view of the vicinity of the sleeve Sectional view along line IV-IV in FIG. The figure which shows the modification which provided multiple oil passages shown in FIG. FIG. 3 is an enlarged cross-sectional view showing a modified example in which a washer that fits airtightly is provided on the outer periphery of the sleeve shown in FIG. Sectional drawing along the VII-VII line of FIG. The figure which shows the modification which provided the circular arc groove in the inner bottom face of the cylinder shown in FIG. The figure which shows the modification which provided multiple oil passages shown in FIG. The figure which shows the modification which provided the convex part in the edge inside the radial direction of the circular arc groove shown in FIG. The figure which shows the modification of a washer shown in FIG. Expanded sectional view showing a conventional auto tensioner Sectional view along line XIII-XIII in FIG.

  FIG. 1 shows a tension adjusting device for a belt 1 for driving an automobile auxiliary machine. This tension adjusting device has a pulley arm 3 supported so as to be swingable about a fulcrum shaft 2 fixed to an engine block (not shown), and a tension pulley 4 rotatably attached to the pulley arm 3.

  One end of an auto tensioner 5 according to an embodiment of the present invention is rotatably connected to the pulley arm 3 via a connecting shaft 6, and the other end of the auto tensioner 5 is supported by a fulcrum shaft 7 fixed to the engine block. Yes. The auto tensioner 5 urges the pulley arm 3 in a direction in which the tension pulley 4 is pressed against the belt 1.

  As shown in FIG. 2, the auto tensioner 5 has a cylinder 8 having a bottom at the bottom, and hydraulic oil is stored in the cylinder 8. In the auto tensioner 5, a cylinder 8 is inclined with respect to a vertical direction, and an inner bottom surface 9 of the cylinder 8 is also inclined with respect to a horizontal direction.

  In the cylinder 8, a sleeve 10 is inserted coaxially with the cylinder 8, and a lower portion of the sleeve 10 is fitted in a sleeve fitting recess 11 formed in the inner bottom surface 9 of the cylinder 8. A rod 12 is inserted into the sleeve 10 so as to be slidable in the axial direction, and the cylinder 8 is partitioned into a pressure chamber 13 and a reservoir chamber 14 by the rod 12 and the sleeve 10.

  A spring seat 15 is fixed to the upper end of the rod 12. The annular opening between the spring seat 15 and the cylinder 8 is closed by a cylindrical rubber bellows 16 that can be expanded and contracted vertically. The upper part of the bellows 16 is fitted on the outer periphery of the spring seat 15, and the lower part of the bellows 16 is fitted on the outer periphery of the cylinder 8.

  A return spring 17 is incorporated in the reservoir chamber 14. The lower end of the return spring 17 is supported by the inner bottom surface 9 of the cylinder 8, and the upper end presses the spring seat 15, thereby urging the rod 12 in a direction protruding from the sleeve 10.

  As shown in FIGS. 3 and 4, between the mating surfaces of the sleeve fitting recess 11 and the sleeve 10, one oil passage 18 that connects the lower part of the pressure chamber 13 and the lower part of the reservoir chamber 14 is formed. . A check valve 19 that allows only the flow of hydraulic oil from the reservoir chamber 14 side to the pressure chamber 13 side is provided at the end of the oil passage 18 on the pressure chamber 13 side.

  On the inner bottom surface 9 of the cylinder 8, one operating oil suction port 20 from the reservoir chamber 14 to the oil passage 18 is opened. The suction port 20 opens only in one of the regions obtained by dividing the inner bottom surface 9 of the cylinder 8 into two by diameter, and the auto tensioner 5 is inclined so that the region is on the lower side. An identification mark 21 indicating the circumferential position of the suction port 20 is provided on the outer periphery of the cylinder 8. Here, the identification mark 21 is a protrusion formed so that the suction port 20 and the circumferential position coincide with each other. The identification mark 21 can be formed by casting the cylinder 8.

  As shown in FIG. 2, the upper part of the pressure chamber 13 and the upper part of the reservoir chamber 14 communicate with each other via the second oil passage 22. The second oil passage 22 has an annular throttle gap 22 a formed between the sliding surfaces of the sleeve 10 and the rod 12, and passes through the inside of the rod 12 and the spring seat 15 from the throttle gap 22 a in order. 14 and an internal passage 22 b communicating with 14.

  As shown in FIG. 3, an O-ring 23 is attached to the outer periphery of the rod 12, and the space between the sliding surface of the rod 12 and the sleeve 10 is sealed by the O-ring 23. Further, the end of the internal passage 22 b on the pressure chamber 13 side is opened on the outer periphery of the rod 12 below the O-ring 23. The throttle gap 22 a constitutes a throttle that limits the flow rate of the hydraulic oil in the second oil passage 22.

  As shown in FIG. 2, the spring seat 15 has a second check valve 24 that allows only the flow of hydraulic oil from the pressure chamber 13 side to the reservoir chamber 14 side of the second oil passage 22, and an energized / non-energized state. An electromagnetic on-off valve 25 that opens and closes the second oil passage 22 by switching is incorporated.

  Next, an operation example of the auto tensioner 5 will be described.

  When the tension of the belt 1 decreases, the rod 12 moves in the protruding direction to a position where the tension of the belt 1 and the biasing force of the return spring 17 are balanced, and the slack of the belt 1 is absorbed. At this time, the check valve 19 is opened, and hydraulic oil flows from the reservoir chamber 14 side to the pressure chamber 13 side through the oil passage 18, so that the rod 12 moves quickly.

  On the other hand, when the tension of the belt 1 increases, the rod 12 moves in the pushing direction to a position where the tension of the belt 1 and the biasing force of the return spring 17 are balanced, and the tension of the belt 1 is absorbed. At this time, the check valve 19 is closed, the hydraulic oil flows from the pressure chamber 13 side to the reservoir chamber 14 side through the second oil passage 22, and a damper action is generated by the viscous resistance of the hydraulic oil flowing through the throttle gap 22a. 12 moves slowly.

  When the electromagnetic opening / closing valve 25 is closed, the hydraulic oil does not flow through the second oil passage 22, so that the movement of the rod 12 in the pushing direction can be prevented. Therefore, when this auto tensioner 5 is employed in an engine that is driven by an alternator (not shown) connected to the belt 1, the engine is started by starting the engine with the electromagnetic on-off valve 25 closed. It is possible to prevent the auxiliary belt 1 from slipping.

  Since the auto-tensioner 5 has the suction port 20 only in one area of the area obtained by dividing the inner bottom surface 9 of the cylinder 8 into two parts by the diameter, the auto-tensioner 5 is inclined by setting the area to the lower side. The suction port 20 can be prevented from being exposed from the oil level of the hydraulic oil in the reservoir chamber 14. Therefore, the auto tensioner 5 can be attached in a state of being largely inclined with respect to the vertical direction, and the degree of freedom of layout of the automobile auxiliary equipment is high.

  In addition, since the auto tensioner 5 is designed so that the circumferential position of the suction port 20 can be recognized by the identification mark 21 on the outer periphery of the cylinder 8, the direction in which the auto tensioner 5 is attached is not easily mistaken, and the suction port 20 is set to the upper side. It is possible to prevent the auto tensioner 5 from being inclined.

  As shown in FIG. 5, a plurality of oil passages 18 (two places in the figure) may be provided at intervals in the circumferential direction. In this way, the flow resistance of the oil passage 18 can be suppressed. Further, even when a foreign substance (such as a suit or contamination) is clogged in any one of the plurality of oil passages 18, the communication between the pressure chamber 13 and the reservoir chamber 14 is ensured through the other oil passages 18. Therefore, reliability against clogging of the oil passage 18 can be ensured.

  As the identification mark 21 indicating the circumferential position of the suction port, a recess formed on the outer periphery of the cylinder 8 may be employed so that the circumferential position of the suction port 20 coincides with that shown in FIG. In addition, when there are a plurality of suction ports 20, a plurality of identification marks 21 may be provided corresponding to each suction port 20, but only one location is provided at the center position of each suction port 20, as shown in FIG. And low cost.

  In the above embodiment, the lower end of the return spring 17 is directly supported by the inner bottom surface 9 of the cylinder 8. However, as shown in FIG. 6, an annular washer 26 that receives the lower end of the return spring 17 is airtightly fitted to the outer periphery of the sleeve 10. The washer 26 is preferably overlapped with the inner bottom surface 9 of the cylinder 8. In this case, as shown in FIG. 7, since the washer 26 covers the portion of the suction port 20 along the outer periphery of the sleeve 10, the suction port 20 opens below the case where the washer 26 is not provided. As a result, it is possible to reliably prevent the suction port 20 from being exposed from the oil level in the reservoir chamber 14.

  When the washer 26 is superposed on the inner bottom surface 9 of the cylinder 8, as shown in FIG. 8, an arc groove 27 extending in an arc shape is formed on the inner bottom surface 9 of the cylinder 8 so as not to be blocked by the washer 26. If the region of the groove 27 that is not blocked by the washer 26 is the suction port 20, the opening area of the suction port 20 is increased, and the suction resistance to the oil passage 18 can be reduced. In this case, if the opening area of the suction port 20 is set larger than the flow passage area of the oil passage 18, the suction resistance to the oil passage 18 can be reliably reduced.

  As shown in FIG. 9, even when a plurality of oil passages 18 are provided, if the region that is not blocked by the washer 26 of the circular arc groove 27 formed on the inner bottom surface 9 of the cylinder 8 is the suction port 20 of each oil passage 18, The opening area of the suction port 20 is increased, and the suction resistance to each oil passage 18 can be reduced.

  As shown in FIG. 10, when the radially inner portion of the arc groove 27 overlaps with the washer 26, it is preferable to provide a convex portion 28 that protrudes radially outward at the radially inner edge of the arc groove 27. In this way, the washer 26 can be received by the convex portion 28, so that it is possible to prevent the washer 26 from being bent due to the reaction force of the return spring 17.

  As the washer 26, a disk-shaped flat washer can be used as shown in FIG. 6, but as shown in FIG. 11, a cylindrical part 26A fitted to the outer periphery of the sleeve 10 with a tightening margin, and its cylindrical part A washer 26 including a flange portion 26 </ b> B formed at the lower end of 26 </ b> A may be employed so that the flange portion 26 </ b> B overlaps the inner bottom surface 9 of the cylinder 8. In this case, since the fitting length between the washer 26 and the sleeve 10 is long, the airtight reliability between the washer 26 and the sleeve 10 can be improved.

5 Auto-tensioner 8 Cylinder 9 Inner bottom surface 10 Sleeve 11 Sleeve fitting recess 12 Rod 13 Pressure chamber 14 Reservoir chamber 17 Return spring 18 Oil passage 19 Check valve 20 Suction port 21 Identification mark 22 Second oil passage 22a Throttle gap 25 Electromagnetic on-off valve 26 Washer 26A Tube portion 26B Flange portion 27 Arc groove 28 Convex portion

Claims (10)

The hydraulic oil is stored in a cylinder (8) having a bottom at the bottom, and the lower portion of the sleeve (10) is fitted into a sleeve fitting recess (11) formed on the inner bottom surface (9) of the cylinder (8). (10) The rod (12) is slidably inserted into the cylinder (8) to divide the inside of the cylinder (8) into a pressure chamber (13) and a reservoir chamber (14), and the rod (12) protrudes from the sleeve (10). A return spring (17) that urges the sleeve in the direction to move the oil passage (18) that communicates the lower portion of the pressure chamber (13) and the lower portion of the reservoir chamber (14) with the sleeve fitting recess (11) and the sleeve. Provided between the fitting surfaces of (10), only the flow of hydraulic oil from the reservoir chamber (14) side to the pressure chamber (13) side is allowed at the end of the oil passage (18) on the pressure chamber (13) side A check valve (19) is provided, and the reservoir (14) in the auto tensioner oil passageway (18) hydraulic oil inlet to the (20) was opened at the inner bottom surface (9) of the cylinder (8) from,
The auto-tensioner characterized in that the suction port (20) is opened only in one of the regions obtained by dividing the inner bottom surface (9) of the cylinder (8) into two by diameter.   An annular washer (26) that receives the lower end of the return spring (17) is airtightly fitted to the outer periphery of the sleeve (10), and the washer (26) is overlapped on the inner bottom surface (9) of the cylinder (8). The auto tensioner according to claim 1, which is combined.   An arc groove (27) extending in an arc shape is formed in the inner bottom surface (9) of the cylinder (8) so as not to be blocked by the washer (26), and the washer (26) of the arc groove (27) The auto tensioner according to claim 2, wherein a region that cannot be blocked is the suction port (20).   The auto tensioner according to claim 3, wherein an opening area of the suction port (20) is set larger than a flow path area of the oil passage (18).   The circular arc groove (27) is formed so that the radially inner portion thereof overlaps the washer (26), and the convex portion (28) protruding radially outward at the radial inner edge of the circular groove (27). The auto tensioner according to claim 3 or 4, wherein   The washer (26) is composed of a cylindrical part (26A) fitted to the outer periphery of the sleeve (10) with a tightening margin, and a flange part (26B) formed at the lower end of the cylindrical part (26A), The auto tensioner according to any one of claims 2 to 5, wherein the flange portion (26B) overlaps the inner bottom surface (9) of the cylinder (8).   The auto tensioner according to any one of claims 1 to 6, wherein a plurality of the oil passages (18) are provided at intervals in the circumferential direction.   The auto tensioner according to any one of claims 1 to 7, wherein an identification mark (21) indicating a circumferential position of the suction port (20) is provided on the cylinder (8).   The auto tensioner according to claim 8, wherein the identification mark (21) is a protrusion or a depression provided on the outer periphery of the cylinder (8) so that the circumferential position of the identification mark (20) coincides with the suction port (20).   The pressure chamber (13) and the reservoir chamber (14) are communicated with each other via a second oil passage (22) provided with a throttle (22a) for restricting the flow rate of hydraulic oil, and the second oil passage (22) is connected to the second oil passage (22). The auto tensioner according to any one of claims 1 to 9, further comprising an electromagnetic on-off valve (25) for opening and closing.

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