JP2003065326A - Rotary supporting apparatus for pulley - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a noise generated during operation of a double row ball bearing 17 regardless of a offset load applied to the double row ball bearing 17 from a pulley 16. SOLUTION: An angular face-to-face duplex bearing is used as the double row ball bearing 17. Even when an outer ring 22 tends to incline based on the offset load, clearance is not produced between each of outer ring raceway tracks 26, 26, inner ring raceway tracks 29, 29 and each of rolling contact surfaces of balls 15, 15. As a result, each of outer ring raceway tracks 26, 26 and inner ring raceway tracks 29, 29 does not violently collide with each of rolling contact surfaces of balls 15, 15. As a result, generation of the noise is prevented.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an endless belt for rotating and driving various accessories attached to an engine for a pulley of a motor vehicle. Is used to rotatably support the pulley over which is mounted the housing and the support shaft. 2. Description of the Related Art Auxiliary equipment such as a compressor for compressing a refrigerant incorporated in an air conditioner for a vehicle is driven to rotate by a traveling engine. For this reason, an endless belt is bridged between a driven pulley provided at the end of the rotating shaft of the auxiliary machine and a driving pulley fixed to the end of the crankshaft of the traveling engine, and the endless belt is circulated. Based on this, the rotation shaft is driven to rotate. Also, the intermediate portion of the endless belt is wound around a guide pulley or a tension pulley to secure the winding angle of the endless belt around the driven pulley or the driving pulley, or to secure the tension of the endless belt. ing. Some of the pulleys incorporated in the auxiliary drive device for automobiles are rotated around a fixed portion such as a housing or a support shaft by a pulley rotation support device according to the present invention. It needs to be freely supported. FIG. 4 shows a structure of a rotary drive portion of a rotary shaft 1 of a compressor as an example of a portion for installing such a pulley rotation support device. The rotating shaft 1 is rotatably supported in the casing 2 by a rolling bearing (not shown). A support cylinder portion 3 provided on an outer surface of an end portion of the casing 2 and corresponding to a fixed portion described in claims.
The driven pulley 4 is rotatably supported by a double-row ball bearing 5 around the periphery. The driven pulley 4 has a U-shaped cross section and is formed in an annular shape as a whole. A solenoid 6 fixed to an end face of the casing 2 is disposed in an internal space of the driven pulley 4. On the other hand, a mounting bracket 7 is fixed to a portion protruding from the casing 2 at the end of the rotating shaft 1, and an annular plate 8 made of a magnetic material is provided around the mounting bracket 7 via a leaf spring 9. I support it. When the solenoid 6 is not energized, the annular plate 8 is separated from the driven pulley 4 as shown in FIG. 4 by the elastic force of the leaf spring 9. However, when the solenoid 6 is energized, the driven pulley 4 to allow the transmission of rotational force from the driven pulley 4 to the rotary shaft 1. That is,
The solenoid 6, the annular plate 8 and the leaf spring 9 constitute an electromagnetic clutch 10 for disengaging the driven pulley 4 and the rotary shaft 1. Conventionally, as the double-row ball bearing 5 constituting the rotary support device for a pulley as described above, a double row ball bearing having a structure in which a pair of angular type ball bearings are combined on the back surface has been used. For this purpose, the outer race 11 constituting the double row ball bearing 5 is provided.
A pair of outer raceways 12, 14 are formed on the inner peripheral surface of the inner ring 13 outward, and a pair of inner raceways 14, 14 are formed on the outer peripheral surface of the inner race 13 inward. And these outer ring tracks 1
As shown in FIG. 4, two balls 15, 15 arranged in plural numbers between the inner races 14, 14 and the inner races 14, 14 clearly indicate the direction of the action line. An outward contact angle is provided. In the case of the conventional structure shown in FIG. 4, an offset load is applied to the outer race 11 constituting the double row ball bearing 5 via the pulley 4 (the line of action is in the width direction from the center of the double row ball bearing 5). It has been known that harsh noise often occurs when a load (deviation load) is applied. A mechanism for generating such noise will be described with reference to FIG. When an offset load F is applied to the outer ring 11 from the pulley, the outer ring 11 swings around the center point O of the double-row ball bearing 5 in a load zone supporting the offset load F. As a result,
As exaggeratedly shown in FIG. 5 by a chain line, the side to which this load is applied (right side in FIG. 5) is radially inward (downward in FIG. 5), and the opposite side (left side in FIG. 5) is radially outward. (Upper part of FIG. 5). Actually, each member including the outer ring 11 is elastically deformed, so that the movement becomes more complicated. However, for the sake of simplicity, FIG. 5 shows each member as a rigid body that does not elastically deform. . As a result of the displacement of the outer race 11, the outer race 12 and the inner race 1 on the side to which the load is applied.
While the contact pressure between the ball 4 and the rolling surface of the ball 15 increases, the contact pressure between the outer ring raceway 12 and the inner ring raceway 14 and the rolling surface of the ball 15 decreases on the opposite side, and a gap tends to occur. become. However, such a gap is generated not on the entire circumference but on the load zone side. In the non-load zone, such a gap does not occur, and the outer raceway 12 and the inner raceway 14
And the rolling surface of the ball 15 is kept in contact. Therefore, the ball 15 present on the opposite side portion is held between the outer raceway 12 and the inner raceway 14 by the revolving motion caused by the rotation of the outer race 11 together with the pulley, , 14 are repeatedly displaced in the radial direction. As a result, the ball 15 existing on the opposite side portion is moved by the outer raceway 12
In addition to generating noise by colliding with the inner ring raceway 14, the outer ring raceway 12 and the inner ring raceway 14 vigorously collide with the outer ring raceway 12 and the inner raceway 14 to generate noise when the vehicle enters the non-loading zone from the load zone. [0007] In order to eliminate the noise generated by the double row ball bearing 5 of the back combination type due to such a cause, a single row deep groove type ball bearing of a four-point contact type is used as a rolling bearing for supporting the pulley. This is described in JP-A-2000-170752. If a four-point contact type single row deep groove ball bearing is used to support the pulley as in the structure described in this publication, all the balls are at least one with respect to the outer raceway and the inner raceway. Since contact occurs at points or more, it is possible to prevent the rolling surfaces of these balls from colliding vigorously with the outer raceway and the inner raceway, thereby preventing noise. [0008] In the case of a single-row deep groove ball bearing of the four-point contact type, the state in which the rolling surface of each ball contacts the outer raceway and the inner raceway at two points is inevitable. Exists. In this state, the contact portion does not become a pure rolling contact state, but becomes a rolling contact state accompanied by a sliding contact state. That is, when a pure radial load is applied to a single-row deep groove ball bearing of a four-point contact type, the rolling surface of each ball, the outer ring raceway and the inner ring raceway are each two points, and each ball has four points. Contact point by point. In this state, each contact portion is in a rolling contact state with a sliding contact state, and a lot of frictional heat is generated in each of these contact portions. When a moment load is applied instead of a pure radial load, the contact point between the rolling surface of some balls and the outer ring raceway and the inner ring raceway becomes one point at a time, and the contact part becomes closer to pure rolling contact, Friction heat generated in the portion is reduced. However, the rolling surfaces of the remaining balls come into contact with one or both of the outer raceway and the inner raceway at two points, and the frictional heat generated at the contact portion increases. As a result, when a large load is supported by a single-row deep groove type ball bearing of a four-point contact type and the bearing is operated at a high speed, the internal temperature of the ball bearing causes the frictional heat generated at each of the contact portions. Will rise significantly based on As a result, the grease sealed in the ball bearing is deteriorated, and the durability of the ball bearing is impaired. If a general single row deep groove ball bearing is used as a rolling bearing to rotatably support the pulley, each contact can be close to a pure rolling contact state, and the temperature rises enough to lead to grease deterioration. Can be prevented, but it cannot be adopted in many cases because of low moment rigidity. That is, in the case of a general single row deep groove ball bearing,
When the moment rigidity is low and a large moment load is applied, it is not always possible to sufficiently prevent the center axis of the outer ring from being inconsistent with the center axis of the inner ring. Also, the load capacity (basic dynamic load rating) is not always sufficient. Because of this,
In many cases, it cannot be adopted unless the offset amount of the center of the pulley with respect to the center of the ball bearing is small and the moment load applied is small, and the tension of the endless belt is weak and the applied radial load is small. The pulley rotation support device of the present invention has been invented in view of such circumstances. [0010] A rotary support device for a pulley according to the present invention, like a rotary support device for a pulley conventionally known, comprises an outer ring having a double-row outer raceway on an inner peripheral surface. , Fixed by a double-row ball bearing comprising an inner ring having a double-row inner raceway on the outer peripheral surface, and a plurality of rollingly provided balls between each of these outer raceways and each of these inner raceways. The pulley is rotatably supported around the portion. In particular, in the pulley rotation support device of the present invention, each ball row constituting the double row ball bearing is a front combination having an inward contact angle. According to the rotary support device for a pulley of the present invention having the above-described structure, even when the outer ring swings and displaces due to the moment load, the outer raceway and the inner raceway and the ball rolling surface can be displaced. Gaps are less likely to occur. As a result, the outer raceway and the inner raceway do not vigorously collide with the rolling surface of the ball, and unpleasant noise is less likely to be generated. In addition, the contact state between the outer raceway and the inner raceway and the ball rolling surface is close to pure rolling contact, as in a four-point contact type ball bearing.
Not much sliding contact. For this reason, the frictional heat generated at the contact portion is reduced, the temperature rise inside the double row ball bearing is suppressed, the deterioration of the grease sealed inside is prevented, and the durability is improved. Further, even if the double row ball bearing is a front combination having a low moment rigidity, it has a large moment rigidity and load capacity (basic dynamic load rating) as compared with a general single row deep groove ball bearing. For this reason, sufficient durability can be ensured from this aspect as well, and the endless belt can be applied even under severe conditions where the tension of the belt is strong and a large radial load is applied. FIG. 1 shows a first embodiment of the present invention. The rotary support device for a pulley of this example is configured so that a pulley 16 is rotatably supported by a double row ball bearing 17 around a fixed portion (not shown) such as a part of a housing or a support shaft. . The pulley 16 is made by subjecting a metal plate such as a steel plate to plastic working such as press working. The pulley 16 is provided concentrically with a supporting cylindrical portion 18 on the inner diameter side and a belt bridging portion 19 on the outer diameter side. One end in the axial direction (the right end in FIG. 1) is connected to each other by an annular continuous portion 20. An inward flange-like flange portion 21 is formed at the other axial edge (left edge in FIG. 1) of the support cylindrical portion 18. Such a pulley 16 is provided on the supporting cylindrical portion 1.
8 is fixed to the outer ring 22 by tightly fitting the outer ring 22 to the outer ring 22 constituting the double row ball bearing 17. The double row ball bearing 17 is provided with the outer race 22 and
An inner ring 23 is provided concentrically with the outer ring 22 on the inner diameter side of the outer ring 22 and a plurality of balls 15, 15. The inner peripheral surface of the outer ring 22 has a large diameter portion 24 at the axial center.
Both ends in the axial direction are small diameter portions 25, 25, and a continuous portion of the large diameter portion 24 and the small diameter portions 25, 25 is an inward outer ring raceway 26, 26, each of which is an angular type. On the other hand, the outer peripheral surface of the inner ring 23 has a large-diameter portion 27 at the center in the axial direction and small-diameter portions 28 at both end portions in the axial direction.
8 are outwardly directed inner raceways 29, 29, each of which is an angular type. And between each of these inner raceways 29, 29 and each of the outer raceways 26, 26,
Each of the balls 15, 15 is provided so as to roll freely while being held by a plurality of holders 30, 30 each. Since the balls 15 are provided between the inward outer raceways 26, 26, each of which is an angular type, and the outward inner raceways 29, 29, the double row ball bearing 1 is provided.
Reference numeral 7 denotes a front combination in which each ball row constituting the double row ball bearing 17 is angular and has an inward contact angle. That is, the two dashed lines β, β shown in FIG. 1 are the directions of the action lines for the respective ball rows,
The distance between β becomes gradually narrower inward in the radial direction from the installation portion of each of the balls 15, 15. According to the rotation supporting device for a pulley of the present invention configured as described above, the outer ring 22 is driven by a moment load.
However, even if it swings around the center of the double row ball bearing 17, even if it is between the outer raceways 26, 26 and the inner raceways 29, 29 and the rolling surfaces of the balls 15, 15, Gaps hardly occur. As a result, these outer raceways 26, 2
6 and the inner raceways 29, 29 and the rolling surfaces of the balls 15, 15 do not vigorously collide with each other, so that harsh noise is less likely to be generated. This point will be described with reference to FIG. 1 and FIG. Since the center of the pulley 16 in the width direction is eccentric with respect to the center of the width of the double row ball bearing 17 by δ shown in FIG. 1, when the endless belt is stretched over the pulley 16, From the pulley 16, the double row ball bearing 17
When the offset load F is applied to the outer ring 22 constituting the outer ring 22, the outer ring 2 is supported by the load zone supporting the offset load F.
2 swings around the center point O of the double row ball bearing 17. As a result, the side to which the offset load F is applied (the right side in FIG. 2) is radially inward (the lower side in FIG. 2) and the opposite side (the left side in FIG. 2). Are displaced radially outward (upward in FIG. 2). In addition, in the case of the present invention as well, each member including the outer ring 22 is actually elastically deformed, so that the movement becomes more complicated. However, for simplification of description, FIG. Expressed as a rigid body. As a result of the displacement of the outer race 22, the outer raceway 26 and the inner raceway 2 on the side to which the load is applied.
While the contact pressure between the ball 9 and the rolling surface of the ball 15 increases, the widthwise outer end of the outer raceway 26 is pressed against the ball 15 on the opposite side. Therefore, in a load zone receiving the offset load F, no gap is formed on the side to which the offset load F is applied and also on the opposite side. Therefore, it is possible to prevent the generation of noise due to the gap, which is generated in the load zone portion on the side opposite to the side where the offset load is applied, which occurs in the conventional structure as described above. The components 1 of the double row ball bearing 17
If each of 5, 22, and 23 is a completely rigid body that is not elastically deformed at all, a state opposite to the load zone shown in FIG. 2 occurs in the non-load zone, which causes noise in the non-load zone. A gap will be created. However, in an actual case, the members 15, 22, and 23 are elastically deformed, and as is apparent from the state in which FIG. 2 is exaggerated, a state opposite to that in FIG. There is no. The state of the gap in the non-load zone is basically the same as the case of the present invention and the case of the prior invention shown in FIGS. Therefore, in the case of the present invention, the noise generated during operation can be reduced as compared with the conventional structure because the gap generated in the load zone is suppressed. The double-row ball bearing 17 is a combination of ball bearings having a contact angle of a front combination (in this case, each of which is an angular type). And each inner raceway 29, 29 and each ball 1
The contact states of the rolling surfaces 5 and 15 are close to pure rolling contact. In other words, unlike a four-point contact type ball bearing, the ratio of sliding contact is not large. For this reason, the frictional heat generated at the contact portion is reduced, the temperature rise inside the double row ball bearing 17 is suppressed, and the deterioration of the grease sealed inside the double row ball bearing 17 is prevented, so that the durability can be improved. Further, the double-row ball bearing 17 has a larger moment than that of a general single-row deep-groove ball bearing even though it is a front combination having a lower moment rigidity than a double-row ball bearing of a rear combination. Has rigidity and load capacity (basic dynamic load rating). For this reason, sufficient durability can be ensured from this aspect, and the endless belt can be applied under severe conditions in which the tension of the endless belt is strong and a large radial load is applied. FIG. 3 shows a second embodiment of the present invention.
An example is shown. In the case of the double row ball bearing 17a of this example,
A double-row outer raceway 26a, 26a each having a deep groove shape is formed on the inner peripheral surface of the outer race 22a, and a double-row inner raceway 29a, 29a, each having a deep-groove type, is formed on the outer peripheral surface of the inner race 23a. . In the case of this example, the two outer raceways 26
a, 26a, the two inner raceways 29a, 29a
By making the pitch smaller than the pitch of
a, each ball 15, 15 provided to be able to roll freely between the
Have an inward contact angle. While the structure of the first example shown in FIGS. 1 and 2 is a structure in which each row is combined with an angular type ball bearing, in the case of this example, each row is a deep groove type. It adopts a structure that combines ball bearings. In the case of such a structure of this example, the same operation and effect as those of the structure of the above-described first example can be obtained. The rotation supporting device for pulleys according to the present invention is constructed and operates as described above, so that it is possible to effectively prevent the generation of abnormal noise during driving and to provide the device to the occupant and the surroundings of the vehicle. This can contribute to the realization of an auxiliary device driving device for an automobile that does not cause discomfort to a pedestrian or the like. In addition, the endless belt can be used under severe conditions, such as ensuring sufficient durability under conditions such as high tension and a large radial load.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partial sectional view showing a first example of an embodiment of the present invention. FIG. 2 is a schematic diagram for explaining the reason why the structure of the present invention hardly generates abnormal noise. FIG. 3 is a partial cross-sectional view showing a second example of the embodiment of the present invention. FIG. 4 is a partial cross-sectional view showing one example of a conventional structure. FIG. 5 is a schematic diagram for explaining the reason why the conventional structure easily generates abnormal noise. [Description of Signs] 1 Rotary shaft 2 Casing 3 Support cylinder 4 Driven pulley 5 Double row ball bearing 6 Solenoid 7 Mounting bracket 8 Annular plate 9 Plate spring 10 Electromagnetic clutch 11 Outer ring 12 Outer ring track 13 Inner ring 14 Inner ring track 15 Ball 16 Pulley 17, 17a Double row ball bearing 18 Support cylindrical part 19 Belt bridge part 20 Continuous part 21 Flange part 22, 22a Outer ring 23, 23a Inner ring 24 Large diameter part 25 Small diameter part 26, 26a Outer ring raceway 27 Large diameter part 28 Small diameter part 29 , 29a Inner ring raceway 30 Cage

Claims (1)

Claims: 1. An outer ring having a double-row outer raceway on an inner peripheral surface, an inner race having a double-row inner raceway on an outer peripheral surface, and between each of these outer raceways and each of these inner raceways. A double-row ball bearing comprising a plurality of rolling-contacting balls, each of which is provided with a plurality of rolling-free balls, wherein the double-row ball bearing comprises: The pulley rotation support device is characterized in that each of the rows of balls has an inward contact angle and is a front combination.