JP5761128B2 - Pivoting arm type belt tensioner - Google Patents

Description

  The present invention relates to a belt tensioner of an internal combustion engine, and more particularly to a pivot arm type belt tensioner.

  In a vehicle such as an automobile, an auxiliary machine such as an alternator is driven by an internal combustion engine for driving the vehicle. A belt is wound around a crank pulley attached to a crankshaft of an internal combustion engine and a pulley of an auxiliary machine, and a driving force is transmitted by the belt. In order for the driving force to be transmitted well by the belt, it is necessary to maintain the belt tension at an appropriate value. Therefore, a belt tensioner is used that maintains the belt tension at an appropriate value by pressing the belt in a direction crossing the moving direction of the belt.

  As one of general belt tensioners, a pivot arm type belt tensioner is well known as described in, for example, Patent Document 1 below. This type of belt tensioner has a pivot arm pivotally supported by an internal combustion engine at one end, and a tension pulley rotatably supported at the other end of the pivot arm. It comes to be pressed.

JP 2011-202778 A

[Problems to be Solved by the Invention]
When a vehicle travels on an unpaved road, such as a rough road, foreign objects such as pebbles are pushed up into the engine room by the tires and fall on the belt tensioner, and the foreign objects are caught between the pivot arm and the tension pulley. May be included. This situation is particularly likely to occur when the pivot arm is pivoted downward in a state of extending substantially horizontally, and if the foreign object bites, smooth operation of the belt tensioner is hindered. .

  Even in the conventional pivot arm type belt tensioner, measures are taken to prevent foreign matter from getting caught between the pivot arm and the tension pulley. Measures to prevent are required.

The present invention has been made in view of the above-mentioned problems in the conventional pivot arm type belt tensioner. The main problem of the present invention is that foreign matter is caught between the pivot arm and the tension pulley. Is to effectively prevent being inserted.
[Means for Solving the Problems and Effects of the Invention]

According to the present invention, the main problem described above includes a pivot arm that is pivotally supported by an internal combustion engine at one end, and a tension pulley that is rotatably supported by the other end of the pivot arm. A pivot arm type belt tensioner in which the pivot arm is biased so that the tension pulley is pressed against the belt, wherein the pivot arm includes upper and lower rib portions toward the internal combustion engine. has a portion forming a cross-section U-shaped open Te, the upper surface of the rib portion of the lower is inclined so that the side of the one end is lower than the side of the other end, the lower rib portion An end portion of the internal combustion engine side of the belt is positioned closer to the internal combustion engine than a side edge of the belt on the internal combustion engine side . Achieved.

According to the above configuration, the upper surface of the lower rib portion of the pivot arm is lower at one end side than the other end side, in other words, the pivot support side is lower than the tension pulley side. So that it is inclined. Therefore, even if the foreign matter falls on the lower rib, the foreign matter moves away from the tension pulley. Therefore, foreign matter may be caught between the lower rib portion and the tension pulley as compared with the case where the upper surface of the lower rib portion is inclined in the reverse direction or extends horizontally. This can be effectively reduced.
Further, according to the above configuration, the end of the lower rib portion on the internal combustion engine side is located closer to the internal combustion engine than the side edge of the belt on the internal combustion engine side. Therefore, the lower rib portion is lower than the case where the end portion on the internal combustion engine side of the lower rib portion is located on the side opposite to the internal combustion engine with respect to the side edge of the belt on the internal combustion engine side. It is possible to reduce the possibility that the falling foreign matter will fall on the belt. Therefore, the possibility that the fallen foreign matter may enter between the belt and the tension pulley can be reduced.

  Further, according to the present invention, in the above configuration, the upper surface of the lower rib portion is inclined so as to become lower toward the internal combustion engine at least at an end portion on the one end portion side. (Constitution of Claim 2)

  According to said structure, compared with the case where the upper surface of a lower rib part is not inclined in the said direction, possibility that a foreign material will accumulate on a lower rib part is reduced, and, thereby, a foreign material The possibility of being caught between the lower rib portion and the tension pulley can be further effectively reduced. Also, due to the swinging of the pivot arm, a flat foreign object that is easily maintained attached to the pivot arm is moved away from the tension pulley and toward the tip of the lower rib part and dropped from the rib part. Can be made.

According to the present invention, in the above-described configuration, in the entire pivot range of the pivot arm, the upper surface of the lower rib portion is lower on the one end side than on the other end side. It is comprised so that it may become (constitution of Claim 3 ).

According to the above configuration, in a part of the entire pivoting range of the pivot arm, the foreign matter is smaller than the case where the upper surface of the lower rib portion is higher on the one end side than on the other end side. Can be effectively reduced from being caught between the lower rib portion and the tension pulley.
[Preferred embodiment of problem solving means]

  According to one preferable aspect of the present invention, in the above configuration, the pivot arm is configured to be pivotally supported at one end portion by a pivot member fixed to the internal combustion engine.

  According to another preferred embodiment of the present invention, in the above configuration, the belt tensioner is configured to have a biasing means for biasing the pivot arm relative to the pivot member.

  According to another preferred embodiment of the present invention, in the above-mentioned configuration, the pivot arm is pivotally supported around the pivot line at one end and parallel to the pivot line at the other end. Configured to support the tension pulley rotatably about a rotational axis.

  According to another preferred aspect of the present invention, in the above configuration, the upper and lower rib portions are not provided in the region of the tension pulley, and the end portions of the upper and lower rib portions are provided. Is configured to be spaced apart from the tension pulley.

  According to another preferred embodiment of the present invention, in the above-described configuration, the upper surface of the lower rib portion is configured to be inclined so as to become lower toward the internal combustion engine over the entire range thereof. The

1 is an elevation view showing an internal combustion engine to which one embodiment of a pivot arm type belt tensioner according to the present invention is applied. FIG. 2 is an enlarged rear view showing the belt tensioner shown in FIG. 1 as viewed from the internal combustion engine side. FIG. 3 is an enlarged sectional view taken along line III-III in FIG. 2. It is explanatory drawing which shows the movement of the foreign material which fell to the lower rib part.

  Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

  In FIG. 1, reference numeral 10 denotes an on-vehicle internal combustion engine, and reference numeral 12 denotes a belt tensioner. The internal combustion engine 10 has a crank pulley 14 attached to one end of a crankshaft (not shown), and the crank pulley 14 rotates around the rotation axis 16 of the crankshaft in the clockwise direction as viewed in FIG. . An annular belt 18 is wound around the crank pulley 14.

  The belt 18 is also wound around an alternator pulley 20, a water pump pulley 22, and an air conditioner pulley 24, and is driven by the crank pulley 14 as indicated by an arrow A in FIG. An alternator pulley 20, a water pump pulley 22, and an air conditioner pulley 24 drive an alternator 26, a water pump 28, and an air conditioner compressor 30, which are auxiliary machines, respectively.

  Since the alternator pulley 20 and the air conditioner pulley 24 engage with the inner peripheral side of the belt 18, they rotate around the rotation axes 32 and 36 parallel to the rotation axis 16 in the clockwise direction as viewed in FIG. 1. On the other hand, since the water pump pulley 22 is engaged with the outer peripheral side of the belt 18, the water pump pulley 22 rotates around the rotation axis 34 parallel to the rotation axis 16 in the counterclockwise direction as viewed in FIG. 1.

  The alternator pulley 20 is located above the crank pulley 14 and the water pump pulley 22, and the air conditioner pulley 24 is located below the crank pulley 14 and the water pump pulley 22. Therefore, the belt 18 moves obliquely upward from the crank pulley 14 toward the alternator pulley 20 between the crank pulley 14 and the alternator pulley 20.

  The belt tensioner 12 is provided above the crank pulley 14 and includes a pivot arm 38 and a tension pulley 40. The pivot arm 38 is pivotally supported at one end by the internal combustion engine 10 and pivots in the vertical direction along the surface of the internal combustion engine. The tension pulley 40 is rotatably supported at the other end of the pivot arm 38, and engages with an outer surface of a portion of the belt 18 between the crank pulley 14 and the water pump pulley 22 so as to allow rolling.

  In particular, in the illustrated embodiment, the belt tensioner 12 includes a pivot member 42 that is fixed to the internal combustion engine 10 by flange portions 42A and 42B. The pivot member 42 pivotally supports one end of the pivot arm 38 so as to be pivotable about a pivot axis 44 parallel to the rotation axis 16. A spring such as a spiral spring that functions as an urging means for urging the pivot arm 38 clockwise as viewed in FIG. 1 is provided between the dome portion 42C of the pivot member 42 and one end of the pivot arm 38. Is built-in. In FIG. 2, reference numeral 42 </ b> D denotes a recess provided in the dome part 42 </ b> C for supporting the spring, and 42 </ b> E is a convex part for receiving a pivot that pivotally supports the pivot arm 38.

  The pivot arm 38 has a shape in which the width gradually decreases from one end to the other end, and supports the tension pulley 40 so that the other end can rotate around a rotation axis 46 parallel to the pivot 44. ing. As shown by arrow B in FIGS. 1 and 2, the tension pulley 40 rolls on the outer surface of the belt 18 by rotating around the rotation axis 46. Therefore, the belt tensioner 12 presses the tension pulley 40 against the portion of the belt 18 between the crank pulley 14 and the alternator pulley 20, thereby applying a required tension to the belt 18.

  As shown in FIGS. 2 and 3, the pivot arm 38 has an upper rib portion 38B and a lower rib portion 38C that are integral with the plate-like portion 38A, and a cross section that opens toward the internal combustion engine 10. It has a U-shaped part. The rib portions 38B and 38C are provided to ensure the strength and rigidity of the pivot arm 38 without increasing its weight. The rib portions 38B and 38C are not provided in the region of the tension pulley 40, and the end portions in the longitudinal direction of these rib portions are separated from the tension pulley 40. The upper surface of the lower rib portion 38C is inclined so that the one end side is lower than the other end side, that is, the pivot member 42 side is lower than the tension pulley 40 side.

  When the internal combustion engine 10 is operated and the belt 18 is driven by the crank pulley 14, the tension of the belt 18 varies, but the belt tensioner 12 reduces the variation of the tension of the belt 18. That is, when the tension of the belt 18 increases, the pressing amount of the tension pulley 40 against the belt 18 decreases. Conversely, when the tension of the belt 18 decreases, the pressing amount of the tension pulley 40 against the belt 18 increases. Further, when the belt 18 expands due to a change with time, the pressing amount of the tension pulley 40 against the belt 18 increases. Therefore, the pivot arm 38 pivots around the pivot axis 44 as the belt 18 stretches due to fluctuations in the tension of the belt 18 and changes with time.

  In FIG. 2, imaginary lines 48H and 48L indicate the upper and lower limits of the range in which the straight line 48 passing along the pivot axis 44 and the rotation axis 46 swings as the pivot arm 38 pivots. Each is shown. As shown in FIG. 2, even if the pivot arm 38 pivots until the straight line 48 is positioned at the lower limit 48L, the upper surface of the lower rib portion 38C is more pivotally supported than the tension pulley 40 side. Keep the side low. The straight line 50 indicates the horizontal direction when the pivot arm 38 pivots to the lower limit, and the upper surface of the lower rib portion 38C forms an angle of 1 ° or more with respect to the straight line 50.

  Further, as shown in FIG. 3, the upper surface of the lower rib portion 38 </ b> C is inclined so as to become lower as it goes away from the plate-like portion 38 </ b> A, that is, toward the internal combustion engine 10. Further, in FIG. 3, a straight line 52 indicates the position of the side edge of the belt 18 on the side of the internal combustion engine 10, and the end of the lower rib portion 38C on the side of the internal combustion engine 10 is the position of the internal combustion engine of the belt. It is located closer to the internal combustion engine than the side edge.

  According to the belt tensioner 12 configured as described above, foreign matter such as pebbles that have been splashed up into the engine room by the tire is caught between the pivot arm 38 and the tension pulley 40, and the tension pulley is excellent. The possibility that the rotation is hindered can be reduced. That is, since the upper surface of the rib portion 38C is inclined as described above, even if the foreign matter 54 falls to the lower rib portion 38C, the foreign matter is not removed as shown by the arrow C in FIG. It moves in a direction away from the tension pulley 40 while moving away from the shape portion 38A. Therefore, as compared with the case where the upper surface of the rib portion 38C is inclined in the opposite direction to the embodiment or extends horizontally, the foreign matter is between the lower rib portion 38C and the tension pulley 40. The possibility of being bitten can be reduced.

  In particular, according to the above-described embodiment, the upper surface of the lower rib portion 38C maintains a state in which the pivot member 42 side is lower than the tension pulley 40 side in the entire pivot range of the pivot arm 38. It is like that. Therefore, for example, in a part of the entire pivot range of the pivot arm 38, the upper surface of the lower rib portion 38C is higher on the pivot member 42 side than the tension pulley 40 side. In comparison, it is possible to effectively reduce the possibility of foreign matter being caught between the lower rib portion and the tension pulley.

  Further, the upper surface of the lower rib portion 38C is inclined so as to become lower as the distance from the plate-like portion 38A increases. Therefore, compared with the case where the upper surface of the lower rib portion 38C is not inclined in this direction, the possibility of foreign matter accumulating on the lower rib portion 38C is reduced, whereby the foreign matter is reduced to the lower rib portion 38C. The possibility of being caught between the portion 38C and the tension pulley 40 can be further effectively reduced.

  Further, the upper surface of the lower rib portion 38C is inclined so as to become lower as the distance from the tension pulley 40 increases and to decrease as the distance from the plate-shaped portion 38A increases. Therefore, when the pivot arm 38 swings, a flat foreign object that is easily maintained on the pivot arm 38 is also moved away from the tension pulley 40 and the plate portion 38A and dropped from the rib portion 38C. be able to.

  Further, the end of the lower rib portion 38C on the internal combustion engine 10 side is located closer to the internal combustion engine than the side edge of the belt on the internal combustion engine side. Therefore, compared with the case where the end of the lower rib portion 38C on the internal combustion engine 10 side is located on the side opposite to the internal combustion engine with respect to the side edge of the belt on the internal combustion engine side, It is possible to reduce the possibility that foreign matter falling from the rib portion 38C will fall on the belt 18. Therefore, the possibility that the fallen foreign matter enters between the belt 18 and the tension pulley 40 can be reduced.

  The material of the pivot arm 38 is used between the upper rib portion 38B and the lower rib portion 38C in order to eliminate the problem of foreign matter entering between the lower rib portion 38C and the tension pulley 40. A structure for filling or covering with a cover or the like is also conceivable. However, in the case of these structures, an increase in the weight of the pivot arm 38 and a complicated structure and an increase in cost of the pivot arm are unavoidable. However, according to the above-described embodiment, these problems occur. Absent.

  Although the present invention has been described in detail with respect to specific embodiments, the present invention is not limited to the above-described embodiments, and various other embodiments are possible within the scope of the present invention. It will be apparent to those skilled in the art.

  For example, in the above-described embodiment, the upper surface of the lower rib portion 38 </ b> C maintains a state in which the pivot member 42 side is lower than the tension pulley 40 side in the entire pivot range of the pivot arm 38. It is supposed to be. However, the above-mentioned state may not be maintained for the entire pivot range of the pivot arm 38.

  In the above-described embodiment, the auxiliary machines driven by the pulleys rotated by the belt 18 are the alternator 26, the water pump 28, and the compressor 30 of the air conditioner. It is not limited to those.

  In the above embodiment, the belt tensioner 12 is provided above the crank pulley 14 and presses the tension pulley 40 against the portion of the belt 18 between the crank pulley 14 and the alternator pulley 20. Yes. However, the position where the belt tensioner 12 is provided and the part where the tension pulley 40 presses the belt may be another position or part.

  In the above-described embodiment, the internal combustion engine 10 is an in-vehicle internal combustion engine. However, the belt tensioner of the present invention may be applied to an internal combustion engine other than the in-vehicle.

  DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine, 12 ... Belt tensioner, 14 ... Crank pulley, 18 ... Belt, 20 ... Alternator pulley, 22 ... Water pump pulley, 24 ... Air conditioner pulley, 38 ... Pivot arm, 40 ... Tension pulley, 42 ... Pivot 38B ... upper rib part, 38C ... lower rib part, 54 ... foreign matter

Claims (3)

A pivot arm pivotally supported at one end by an internal combustion engine; and a tension pulley rotatably supported at the other end of the pivot arm, the tension pulley being pressed against the belt In a pivot arm type belt tensioner in which the pivot arm is biased, the pivot arm includes upper and lower rib portions and has a U-shaped section opened toward the internal combustion engine. The upper surface of the lower rib portion is inclined so that the one end portion side is lower than the other end portion side, and the end portion on the internal combustion engine side of the lower rib portion is the belt A pivot arm type belt tensioner, which is located closer to the internal combustion engine than a side edge of the internal combustion engine .   2. The pivot arm type according to claim 1, wherein an upper surface of the lower rib portion is inclined so as to become lower toward the internal combustion engine at least at an end portion on the one end portion side. Belt tensioner. The upper surface of the lower rib portion is inclined so that the one end side is lower than the other end side in the entire pivot range of the pivot arm. Or a pivot arm type belt tensioner according to 2;

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