JP2005221063A - Pulley - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pulley capable of restricting run-off of a transmission belt from a belt guide part without increasing the number of parts items. <P>SOLUTION: The pulley 18 formed by plastically machining a plate material such as a steel plate is provided with at least an outside cylindrical part 27 having the belt guide part 28, on which the transmission belt 21 is to be hooked, in the periphery thereof and an annular outside flange part 26 integrally formed with one end (a right end in a figure) of the outside cylindrical part 27. In this pulley 18, the outside cylindrical part 27 is formed into a taper shape having a radius to be enlarged as separating from the outside flange part 26 in the axial direction. Furthermore, the pulley 18 is provided with an inside cylindrical part 25 integrally formed with an inner peripheral edge part of the outside flange part 26. The pulley 18 with this structure is supported in a housing 31 of a water pump by a rolling bearing 32 installed in a bearing installation part 29 of the inside cylindrical part 25, and driven for rotation around the center shaft 30 with operation of the water pump. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a pulley used in a winding transmission device, and more particularly to a pulley formed by plastic working a plate material (sheet metal) such as a steel plate with a press or the like.

  As one form of a pulley used for a winding transmission device such as an engine, for example, in Patent Document 1, instead of a conventional casting, a sheet material (sheet metal) such as a steel plate is formed by plastic working with a press or the like. A thing (sheet metal pulley) is described. The pulley includes an inner small-diameter cylindrical portion and an outer large-diameter cylindrical portion that are positioned concentrically with each other, and an annular flange portion that couples the cylindrical portions with an interval in the radial direction. And an outer side large diameter cylindrical part has a belt guide part in the outer peripheral surface.

  Such pulleys can be reduced in weight and cost, but have lower strength than cast products. In particular, since the pulley has a so-called cantilever structure in which the outer large-diameter cylindrical portion is connected to the flange portion only at one end portion thereof, the outer large-diameter cylindrical portion tends to have insufficient rigidity. The following phenomena may occur due to the cause.

  For example, when the winding transmission device is assembled, belt tension is applied to the pulley from the transmission belt when the transmission belt is hung on the pulley. Further, the belt tension fluctuates accordingly when the rotation of the crankshaft fluctuates during engine operation. Further, the belt tension fluctuates also when the inter-axis distance of the auxiliary machine or the like changes more than the expansion / contraction amount of the transmission belt with temperature change. If a large force is applied by these belt tensions, fluctuations in the belt tension, etc., the outer large-diameter cylindrical part bends inward and decreases in diameter in the axial direction away from the flange part, the transmission belt has its diameter reduced. May be displaced to the smaller side of the belt and come off the belt guide.

  Therefore, it is necessary to take measures to prevent the transmission belt from being detached from the belt guide portion. In Patent Document 1, a reinforcing ring is fixed to the inner peripheral surface of the end portion opposite to the flange portion of the outer large-diameter cylindrical portion.

As prior art documents according to the present invention, in addition to Patent Document 1, the following Patent Documents 2 to 4 are listed.
JP 59-126160 A (FIGS. 3 to 6) Japanese Utility Model Publication No.59-039354 Japanese Patent Laid-Open No. 8-178022 Japanese Patent Laid-Open No. 8-178023

  However, in Patent Document 1 described above, the rigidity of the outer large-diameter cylindrical portion is increased by the reinforcing ring, and the outer large-diameter cylindrical portion is prevented from bending inward by belt tension, so that the transmission belt is detached from the belt guide portion. Although it can be made difficult, the amount of the reinforcing ring, the number of parts, and the weight increase, which impairs the advantage of weight reduction by the pulley.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a pulley capable of suppressing the transmission belt from being detached from the belt guide without increasing the number of parts.

In the following, means for achieving the above object and its effects are described.
The invention according to claim 1 is a pulley that is formed of a plate and is driven to rotate around a central axis, the tubular portion having a belt guide portion around which a transmission belt is hung, and the tubular portion. And at least one annular flange portion formed integrally with one end of the cylindrical portion, and the cylindrical portion has a taper shape whose diameter increases as the distance from the flange portion increases in the axial direction.

  Since the so-called cantilever structure in which the tubular portion is connected to the flange portion only at one end thereof is employed in the pulley having the above configuration, the tubular portion is likely to have insufficient rigidity. Therefore, when a large force is applied due to the belt tension of the transmission belt, fluctuations in the belt tension, or the like, the cylindrical portion may be bent inward.

  In this respect, in the first aspect of the present invention, the cylindrical portion has a tapered shape whose diameter increases as the distance from the flange portion increases in the axial direction. Therefore, by considering the amount of deflection due to belt tension and appropriately setting the degree of diameter expansion (taper angle), it is possible to prevent the cylindrical portion from becoming a tapered shape that decreases in diameter in the axial direction. Thus, it is possible to suppress a phenomenon in which the transmission belt is displaced to the side away from the flange portion and is detached from the belt guide portion. A separate member such as a reinforcing ring is not used to solve this problem. For this reason, the new problem of an increase in the number of parts and weight accompanying the addition of another member hardly occurs. Thus, according to the first aspect of the present invention, it is possible to suppress the transmission belt from being detached from the belt guide portion without increasing the number of parts.

  According to a second aspect of the present invention, in the first aspect of the present invention, in the first aspect of the present invention, a bearing mounting portion that is integrally formed on the inner peripheral edge of the flange portion and is mounted with a rolling bearing so as to be positioned in the cylindrical portion. In the state where the transmission belt is hung on the belt guide portion, a line passing through the intermediate portion in the axial direction of the belt guide portion perpendicular to the central axis is perpendicular to the central shaft and the bearing is mounted. It is assumed that the flange portion is offset from the line passing through the intermediate portion in the axial direction of the portion.

  Here, according to the first aspect of the invention, even if the diameter of the cylindrical portion in a state where the transmission belt is hung is substantially uniform at any location, the axially intermediate portion of the belt guide portion due to misalignment or the like. If there is a deviation from the bearing mounting portion to the side opposite to the flange, there is the following concern. That is, when there is play in the rolling bearing and the belt tension fluctuates and increases as described above, the outer ring of the rolling bearing is inclined to the side away from the flange portion. The degree of inclination increases as the amount of deviation of the belt guide portion increases. With the inclination of the outer ring, the tubular portion may bend more greatly inward as it moves away from the flange portion in the axial direction, and the transmission belt may be displaced away from the flange portion.

  In this regard, in the invention described in claim 2, in a state where the transmission belt is hung on the belt guide portion, a line passing through the intermediate portion in the axial direction of the belt guide portion perpendicular to the central axis of the pulley is the same central axis. It is offset to the flange portion side with respect to a line passing through the axial intermediate portion of the bearing mounting portion at right angles. For this reason, even if there is play or misalignment of the rolling bearing as described above, the outer ring is inclined toward the side closer to the flange portion. This inclination cancels the bending of the tubular portion so that the diameter of the tubular portion decreases as the distance from the flange portion increases in the axial direction. For this reason, the amount of bending of the cylindrical portion is reduced, the transmission belt is less likely to be displaced away from the flange portion, and the phenomenon that the transmission belt is detached from the belt guide portion is more reliably suppressed.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, at the end of the cylindrical portion opposite to the flange portion, the same cylinder is separated from the belt guide portion in the axial direction. It is assumed that the auxiliary taper portion having a larger diameter than the shape portion is integrally formed.

  Here, in the pulley, even if the diameter of the cylindrical portion in a state where the transmission belt is hung is substantially uniform at any location, if the belt tension temporarily increases for some reason, the cylindrical portion There is a risk that the transmission belt is displaced toward the side away from the flange portion.

  In this respect, in the invention according to claim 3, the auxiliary taper portion is formed at the end of the cylindrical portion opposite to the flange portion. For this reason, when the transmission belt reaches the auxiliary taper portion with the displacement, the transmission belt tries to ride on the auxiliary taper portion while expanding the diameter. In this state, a force for reducing the diameter is generated in the transmission belt by its own elastic restoring force. For this reason, the transmission belt riding on the auxiliary taper portion tends to return to the small diameter side, that is, the belt guide portion side along the auxiliary taper portion. Therefore, it is possible to more reliably suppress the problem that the transmission belt is detached from the belt guide portion.

(First embodiment)
A first embodiment in which the present invention is embodied in a pulley used in an engine winding transmission will be described below with reference to FIGS. FIG. 2 shows a schematic configuration of the winding transmission device. As shown in FIG. 2, a crank pulley 13 is attached to a crankshaft 12 that is a drive shaft of the engine 11 so as to be integrally rotatable. Further, in the vicinity of the crank pulley 13, auxiliary machines (not shown) such as an alternator, a water pump, and an air conditioner compressor are arranged, and pulleys 17, 18, and 19 are respectively connected to the rotary shafts 14, 15, and 16, respectively. It is attached so that it can rotate integrally. A transmission belt 21 is wound around the crank pulley 13 and the pulleys 17 to 19 as a winding transmission member. Here, as shown in FIG. 1, the transmission belt 21 is formed with a plurality of ribs 22 having a substantially V-shaped cross section on one surface (upper surface in FIG. 1), and the other surface (lower surface in FIG. 1). A so-called V-ribbed belt formed flat is used. In FIG. 1, the core wire in the V-ribbed belt is not shown.

  The transmission belt 21 is hung on the crank pulley 13 and the pulleys 17 and 19 on the side having the ribs 22, and is hung on the pulley 18 of the water pump on the flat side. In the winding transmission device having such a configuration, when the crankshaft 12 rotates in the clockwise direction in FIG. 2 as the engine 11 is operated, the rotation is transmitted to each auxiliary machine via the crank pulley 13, the transmission belt 21, and the pulleys 17 to 19. Are transmitted to the rotating shafts 14-16. In this transmission process, the transmission belt 21 circulates in the clockwise direction as indicated by an arrow in FIG.

  Next, details of the pulley 18 of the water pump will be described. FIG. 1 shows the pulley 18 in a state before the transmission belt 21 is hung, and FIG. 3 shows the pulley 18 in a state where the transmission belt 21 is hung. The pulley 18 is formed by plastic processing of a single sheet material (sheet metal) made of a steel sheet or the like having a certain thickness using a press or the like. The pulley 18 includes a shaft portion 23, an inner flange portion 24, an inner cylindrical portion 25, an outer flange portion 26, an outer cylindrical portion 27, a belt guide portion 28, and a bearing mounting portion 29, and a central shaft 30. Is driven to rotate by a water pump.

  The shaft portion 23 has a bottomed cylindrical shape in which one end (right side in the figure) is closed. The inner flange portion 24 has an annular shape and is orthogonal to the central shaft 30, and is formed integrally with the opening end of the shaft portion 23 at the inner peripheral edge portion of the inner flange portion 24. The inner cylindrical portion 25 has a cylindrical shape with a diameter larger than that of the shaft portion 23, and is disposed outside the shaft portion 23 at a predetermined distance. The inner cylindrical portion 25 is formed integrally with the outer peripheral edge portion of the inner flange portion 24 at one end (left side in the drawing). The outer flange portion 26 has an annular shape and is orthogonal to the center axis 30, and is formed integrally with the other end (right side in the drawing) of the inner cylindrical portion 25 at the inner peripheral edge of the outer flange portion 26. ing.

  The outer cylindrical portion 27 has a tapered shape starting from the outer peripheral edge portion of the outer flange portion 26 and increasing in diameter as it approaches the inner flange portion 24 (away from the outer flange portion 26) in the axial direction. The angle α formed with respect to the central axis 30 of the outer cylindrical portion 27 is determined when the outer cylindrical portion 27 is bent inward by the belt tension (total) of the following (i) to (iii) received from the transmission belt 21. The diameter of the outer cylindrical portion 27 is set to be substantially the same at any location.

(I) Initial belt tension received by the outer cylindrical portion 27 from the transmission belt 21 in a state where the transmission belt 21 is hung on the belt guide portion 28 (engine stopped state).
(Ii) The maximum value of the belt tension when the belt tension of the transmission belt 21 fluctuates with the rotation fluctuation of the crankshaft 12 during the operation of the engine 11.

  (Iii) Due to the difference between the amount of change in the interval (distance between the shafts) of the rotating shafts 14 to 16 of adjacent auxiliary machines and the amount of expansion / contraction of the transmission belt 21 due to the same temperature change, the transmission belt 21 The belt tension when the belt tension increases.

  As shown by a thick line in FIG. 1, the belt guide portion 28 is a portion where the transmission belt 21 is hung on the flat side surface, and is constituted by a part of the outer peripheral surface of the outer cylindrical portion 27. Further, as indicated by a thick line in FIG. 1, the bearing mounting portion 29 is a portion where an outer ring 34 of a rolling bearing 32 described later is mounted, and is configured by a part of the inner peripheral surface of the inner cylindrical portion 25.

  The pulley 18 of the present embodiment is configured as described above. In a state where the pulley 18 is attached to the water pump, the shaft portion 23 is inserted into a cylindrical support portion 31A provided in the housing 31 of the water pump. The pulley 18 is rotatably supported by the support portion 31A by a rolling bearing 32 interposed between the inner cylindrical portion 25 and the support portion 31A. The rolling bearing 32 includes an inner ring 33 and an outer ring 34 arranged concentrically with each other, and a rolling element 35 formed of a spherical body interposed between the inner ring 33 and the outer ring 34. The inner ring 33 is fitted into the support portion 31 </ b> A, and the outer ring 34 is fitted into the inner cylindrical portion 25 and contacts the bearing mounting portion 29.

  The pulley 18 has a so-called cantilever structure in which the outer cylindrical portion 27 is connected to the outer flange portion 26 only at one end (right side in FIG. 1). Rigidity in the outer cylindrical portion 27 is lower than that of the manufactured one. Therefore, when a large belt tension is applied to the pulley 18, the inner cylindrical portion 27 becomes smaller (decreasing in diameter) as the outer cylindrical portion 27 approaches the inner flange portion 24 in the axial direction (away from the outer flange portion 26). Can be bent in the direction. As a situation where a large tension is applied, for example, when the transmission belt 21 is hung on the pulley 18 in a stopped state and the belt tension is applied, or when the belt tension fluctuates with the rotation of the crankshaft 12 during the operation of the engine 11. A case where the belt tension fluctuates in accordance with a change in the distance between the shafts accompanying a change in temperature is mentioned.

  However, in the first embodiment, in the initial state where the transmission belt 21 is not hung, the outer cylindrical portion 27 is formed in advance in a tapered shape that increases in diameter as the distance from the outer flange portion 26 increases in the axial direction. Therefore, even if the outer cylindrical portion 27 is bent due to the belt tension as described above, the outer cylindrical portion 27 is unlikely to be tapered such that the outer cylindrical portion 27 is reduced in diameter as the distance from the outer flange portion 26 increases. After the bending, as shown in FIG. 3, the diameter of the outer cylindrical portion 27 becomes substantially uniform at any location. Therefore, the problem that the transmission belt 21 is displaced to the side away from the outer flange portion 26 and is detached from the belt guide portion 28 is less likely to occur.

According to the first embodiment described in detail above, the following effects can be obtained.
In the pulley 18 formed by plastic processing of a sheet metal such as a steel plate with a press or the like, the outer cylindrical portion 27 is formed in a taper shape whose diameter increases as the distance from the outer flange portion 26 increases in the axial direction. For this reason, the degree of diameter expansion (taper angle α) is set to an appropriate value in consideration of the amount of bending due to the belt tension, whereby the belt tension by the transmission belt 21 is applied and the outer cylindrical portion 27 moves inward. Even if it bends, it is possible to suppress a phenomenon in which the outer cylindrical portion 27 becomes tapered such that the outer cylindrical portion 27 decreases in diameter as it moves away from the outer flange portion 26 in the axial direction. Unlike Patent Document 1, no separate member such as a reinforcing ring is used to solve this problem. For this reason, the malfunction that the transmission belt 21 comes off from the belt guide part 28 can be suppressed without accompanying the new problem of the number of parts and weight increase accompanying the addition of another member. The advantage of the sheet metal pulley 18 in terms of weight reduction and cost reduction can be maintained.

(Second Embodiment)
Next, a second embodiment embodying the present invention will be described with reference to FIGS. In the second embodiment, as shown in FIG. 5, in a state where the transmission belt 21 is hung on the belt guide portion 28, a line 41 passing through the intermediate portion in the axial direction of the belt guide portion 28 perpendicular to the central axis 30 of the pulley 18. Is offset to the outer flange portion 26 side with respect to a line 42 passing through the intermediate portion in the axial direction of the bearing mounting portion 29 perpendicular to the central shaft 30. The amount of this offset is set to a value larger than the maximum value of the misalignment amount. The misalignment amount is a shift amount in the axial direction of the two lines 41 and 42 caused by dimensional variation of the rolling bearing 32, assembly error, and the like. Other configurations are the same as those in the first embodiment. For this reason, the same members and portions as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  Such a configuration is adopted because even if the diameter of the outer cylindrical portion 27 in a state where the transmission belt 21 is hung is substantially uniform at any location, the axial middle of the transmission belt 21 is temporarily misaligned. This is because if the portion is displaced to the inner flange portion 24 side from the rolling bearing 32, there is the following concern. If the rolling bearing 32 has a backlash, if the belt tension fluctuates and increases due to the rotation fluctuation of the crankshaft 12, the side where the upper half of the outer ring 34 separates from the outer flange 26 due to the backlash (the left side of the figure). ). The degree of this inclination increases as the deviation amount of the belt guide portion 28 increases. As the outer ring 34 is tilted, the outer cylindrical portion 27 is bent more inwardly as it is separated from the outer flange portion 26 in the axial direction (closer to the inner flange portion 24), and the transmission belt 21 is moved away from the outer flange portion 26. There is a risk of displacement to the side.

  In this respect, according to the pulley 18 of the second embodiment, even if there is a backlash or misalignment of the rolling bearing 32 as described above, the outer ring 34 has a side closer to the outer flange portion 26 (the right side in the figure). ). This inclination cancels the bending of the outer cylindrical portion 27 so as to decrease in diameter as it moves away from the outer flange portion 26 in the axial direction due to the belt tension. For this reason, the amount of bending of the outer cylindrical portion 27 can be reduced, and the transmission belt 21 can be hardly displaced to the side away from the outer flange portion 26. As a result, it is possible to more reliably suppress the transmission belt 21 from being detached from the belt guide portion 28.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIGS. In the third embodiment, as shown in FIG. 6, an auxiliary taper portion 45 is integrally formed at the end of the outer cylindrical portion 27 opposite to the outer flange portion 26 (left side in FIG. 7). The auxiliary taper portion 45 has a diameter larger than that of the outer cylindrical portion 27 as the distance from the belt guide portion 28 in the axial direction starts from the opening end of the outer cylindrical portion 27. The angle β formed with respect to the outer cylindrical portion 27 of the auxiliary taper portion 45 is necessary for returning to the original proper position when the transmission belt 21 is displaced from the outer flange portion 26 toward the inner flange portion 24 side. It is set to a size that can generate a large force. Other configurations are the same as those in the first embodiment. For this reason, the same members and portions as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  Here, in the pulley 18, as shown in FIG. 7, even if the diameter of the outer cylindrical portion 27 in a state where the transmission belt 21 is hung is uniform at any location, the rotational fluctuation of the crankshaft 12, etc. If the belt tension temporarily increases along with this, the outer cylindrical portion 27 may be bent inward, and the transmission belt 21 may be displaced away from the outer flange portion 26. However, when the transmission belt 21 reaches the auxiliary taper portion 45, the transmission belt 21 tends to ride on the auxiliary taper portion 45 while expanding its diameter as shown in FIG. In this state, a force for reducing the diameter is generated in the transmission belt 21 by its own elastic restoring force. With this force, the transmission belt 21 riding on the auxiliary taper portion 45 tends to return to the small diameter side, that is, the belt guide portion 28 side along the auxiliary taper portion 45.

Therefore, according to the pulley 18, in addition to the effect described in the first embodiment, the phenomenon that the transmission belt 21 is disengaged from the belt guide portion 28 can be more reliably suppressed.
Note that the present invention can be embodied in another embodiment described below.

-You may form the auxiliary taper part 45 in 3rd Embodiment in the outer cylindrical part 27 in the pulley 18 of 2nd Embodiment integrally.
The present invention is also applicable to a pulley on which a type of transmission belt other than the V-ribbed belt is hung. Examples of such a transmission belt include a flat belt and a timing belt. Note that this is not applicable when the V-ribbed belt is hooked on the pulley 18 on the rib 22 side. This is because the transmission belt 21 does not slip (displace) on the belt guide portion 28 even if the outer cylindrical portion 27 is reduced in diameter in the axial direction so as to move away from the outer flange portion 26 due to belt tension. In short, any transmission belt that can slide on the outer cylindrical portion 27 can be a target of the transmission belt hung on the pulley of the present invention.

  -You may change the shape of the pulley 18 suitably on condition that "it is provided with the outer side cylindrical part 27 and the outer side flange part 26 at least." For example, the inner flange portion 24 and the shaft portion 23 may be omitted.

In 1st Embodiment which actualized this invention, the fragmentary sectional view which shows the state before a transmission belt is hung on a pulley. The schematic block diagram of a winding transmission apparatus. The fragmentary sectional view which shows the state in which the belt tension by a transmission belt was added to the pulley. In 2nd Embodiment which actualized this invention, the fragmentary sectional view which shows the state before a transmission belt is hung on a pulley. The fragmentary sectional view which shows the state in which the belt tension by a transmission belt was added to the pulley. In 3rd Embodiment which actualized this invention, the fragmentary sectional view which shows the state before a transmission belt is hung on a pulley. The fragmentary sectional view for demonstrating the effect | action of the auxiliary taper part in a pulley.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 18 ... Pulley, 21 ... Transmission belt, 26 ... Outer flange part, 27 ... Outer cylindrical part, 28 ... Belt guide part, 29 ... Bearing mounting part, 30 ... Center axis, 32 ... Rolling bearing, 41, 42 ... Line, 45 ... Auxiliary taper part.

Claims (3)

A pulley formed of a plate material and driven to rotate about a central axis,
A cylindrical portion having a belt guide portion around which a power transmission belt is hung, and an annular flange portion formed integrally with one end portion of the cylindrical portion; A pulley having a taper shape whose diameter increases as the distance from the flange portion increases. A bearing mounting portion formed integrally with the inner peripheral edge of the flange portion so as to be located in the cylindrical portion, and mounted with a rolling bearing;
In a state in which the transmission belt is hung on the belt guide portion, a line passing through the intermediate portion in the axial direction of the belt guide portion perpendicular to the central axis is perpendicular to the central axis and the axial direction of the bearing mounting portion. The pulley according to claim 1, wherein the pulley is offset toward the flange portion with respect to a line passing through the intermediate portion. The auxiliary taper part which expands larger diameter than the said cylindrical part is integrally formed in the edge part on the opposite side to the said flange part of the said cylindrical part from the said belt guide part about an axial direction. The pulley according to 1 or 2.

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