JP2017172671A - Pulley with limiter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pulley including a limiter capable of shutting off a transmittance of a rotating torque between the pulley and a hub when a rotating load becomes excessive and hardly producing irregular sound even if the pulley is rotated under that state.SOLUTION: This invention relates to a pulley with a limiter having a torque limiter 3 for shutting off a transmittance of a rotation torque from a pulley 1 to a hub 2 when a rotating load of a shaft 13 to be driven becomes excessive. The torque limiter 3 employs a configuration comprising a V-groove 23 arranged at an outer periphery of the hub 2; a ball 24 stored in the V-groove 23; a spring piece 31 flexed toward outside in a radial direction when the ball 24 is moved to outside in a radial direction to apply a biasing force to the ball 24 inward in a radial direction; and a ball storing part 35 for receiving the ball 24 when the ball 24 pushes the hole part 32 and the separating part 33 and passes outward in a radial direction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a pulley with a limiter used mainly for a driven shaft of a compressor for a car air conditioner.

  A compressor for a car air conditioner is driven by transmitting rotation generated on a crankshaft of an engine to a driven shaft of the compressor via a drive belt. On the other hand, variable capacity compressors are generally used as compressors for car air conditioners. The variable capacity compressor is a compressor capable of changing the compression capacity from outside. When such a variable displacement compressor is used in a car air conditioner, it is possible to control the compressor to be in a zero compression state, and therefore, between the pulley around which the drive belt is wound and the driven shaft of the compressor, There is no need to incorporate a clutch (such as an electromagnetic clutch) that switches between transmission and disconnection of rotational torque by operation.

  On the other hand, when a compressor for a car air conditioner breaks down, the rotational load on the driven shaft of the compressor suddenly increases. In this case, if the pulley stops rotating while the drive belt continues to travel, the drive belt may be abruptly worn and cut, and the automobile may not be able to travel. Therefore, in order to maintain a state in which the automobile can run even if the compressor is damaged, a pulley with a limiter is generally used as a pulley for a driven shaft of the compressor.

  A pulley with a limiter includes a pulley around which a driving belt is wound, a hub fixed to a shaft end portion of a driven shaft, and a torque limiter that transmits rotational torque from the pulley to the hub (for example, Patent Document 1). -3). The torque limiter protects the drive belt by causing the pulley to run idle by interrupting transmission of rotational torque from the pulley to the hub when the rotational load of the driven shaft becomes excessive.

International Publication No. 2014/148414 International Publication No. 2014/157276 JP 2014-185776 A

  A torque limiter of a pulley with a limiter described in Patent Documents 1-3 is connected to a flange portion integrally formed with a hub fixed to a shaft end portion of a driven shaft, and one end of the flange portion is detachably connected to the flange portion. The other end has a connecting piece fixed to the side surface of the pulley. And when the rotational load of the driven shaft becomes excessive, one end of the connecting piece and the flange portion of the hub are disconnected, so that the transmission of rotational torque between the pulley and the hub is cut off (disconnected state) )

  However, the torque limiter of the pulley with a limiter described in Patent Documents 1-3 is a connecting piece that rotates integrally with the pulley when the end of the connecting piece and the flange portion of the hub are disconnected. And the hub flange fixed to the driven shaft repeatedly collided with the rotation of the pulley, and there was a problem that the noise was large and the noise was large.

  The problem to be solved by the present invention is that transmission of rotational torque between the pulley and the hub can be cut off when the rotational load becomes excessive, and abnormal noise is generated even if the pulley rotates in that state. It is to provide a pulley with a limiter that is difficult to perform.

In order to solve the above problems, the present invention provides a pulley with a limiter having the following configuration.
A pulley around which a drive belt is wound, a hub fixed to a shaft end of a driven shaft located at the rotation center of the pulley, and when the rotational load of the driven shaft is in a normal range, the pulley A torque limiter, wherein the torque limiter includes: a torque limiter that transmits a rotational torque to the hub and interrupts transmission of the rotational torque from the pulley to the hub when the rotational load of the driven shaft becomes excessive. Is fitted with the V-groove provided in the outer periphery of the hub, the ball accommodated in the V-groove, and the ball so that the radial depth gradually decreases from the circumferential center toward both sides in the circumferential direction. A hole portion and a separation portion that divides the circumference of the hole portion, and when the ball moves radially outward, the ball bends radially outward to bias the ball radially inward If you give Limiter pulley and having a strip, and a ball receiving portion for receiving the ball when the ball has passed radially outwardly push the said separation portion and said bore portion.

  In this way, the ball moves radially outward along the V-groove while deflecting the spring piece radially outward according to the rotational torque acting between the pulley and hub, and the pulley and hub Relative displacement in the circumferential direction. Therefore, fluctuations in the rotational load of the driven shaft and fluctuations in rotational torque transmitted from the drive belt to the pulley can be absorbed between the pulley and the hub, and a damper action can be obtained. And when the rotational load of the driven shaft becomes excessive, the ball expands the hole portion and the separation portion of the spring piece and passes radially outward, and the ball is received in the ball housing portion. Become. In this state, since there is no ball in the V-groove, transmission of rotational torque between the pulley and the hub is interrupted. Further, even if the pulley rotates in this state, there is no portion that repeatedly collides with the rotation of the pulley, so that abnormal noise is unlikely to occur.

  The torque limiter is positioned with a gap in the radially outward direction of the spring piece, and receives a spring piece when the spring piece is bent in the radial outward direction to restrict the amount of deflection of the spring piece. It is preferable to employ a structure further having a portion.

  In this way, it is possible to set a relatively large rotational torque at which the torque limiter operates, while ensuring a damper action due to the ball moving along the V-groove.

For example, the torque limiter having the following configuration can be adopted.
A first annular plate that is fixed to a side surface of the pulley; and a second annular plate that is provided to face the first annular plate in an axial direction. The stopper is provided at the radially inner end of the first annular plate, and is provided at the radially inner end of the second annular plate. It is a space formed between the opposing surfaces of the first annular plate and the second annular plate.

  In this case, the second annular plate includes an inner flat plate portion arranged in parallel with the first annular plate at an interval in the axial direction, and the first annular plate from the radial inner end of the inner flat plate portion. An inner cylindrical portion extending in the axial direction toward the annular plate, and at least a pair of slits formed across the inner cylindrical portion in the axial direction, and the spring piece is formed between the pair of slits. The thing of the structure which can be employ | adopted is employable.

  Preferably, the at least one pair of slits is formed so as to extend radially outward from the boundary between the inner cylindrical portion and the inner flat plate portion.

  If it does in this way, it will become easy to elastically deform a spring piece, and it will become possible to obtain a damper operation effectively.

  The width of each of the at least one pair of slits is preferably set to be smaller than the outer diameter of the ball.

  If it does in this way, when a ball storage part receives a ball, it can prevent that ball falls through a slit.

  According to the pulley with a limiter of the present invention, the ball moves radially outward along the V-groove while the ball deflects the spring piece radially outward according to the rotational torque acting between the pulley and the hub. And the hub are relatively displaced in the circumferential direction. Therefore, fluctuations in the rotational load of the driven shaft and fluctuations in rotational torque transmitted from the drive belt to the pulley can be absorbed between the pulley and the hub, and a damper action can be obtained. And when the rotational load of the driven shaft becomes excessive, the ball expands the hole portion and the separation portion of the spring piece and passes radially outward, and the ball is received in the ball housing portion. Become. In this state, since there is no ball in the V-groove, transmission of rotational torque between the pulley and the hub is interrupted. Further, even if the pulley rotates in this state, there is no portion that repeatedly collides with the rotation of the pulley, so that abnormal noise is unlikely to occur.

Sectional drawing which shows the pulley with a limiter of embodiment of this invention Fig. 1 is a right side view of the pulley with limiter shown in Fig. 1. Sectional view along line III-III in FIG. Sectional view along line IV-IV in FIG. The perspective view which takes out and shows the 2nd annular plate of the pulley with a limiter shown in FIG. (A) is an enlarged view of the vicinity of the V groove in FIG. 3, (b) is a cross-sectional view taken along line VI-VI in (a). 6A is a view showing a state in which the ball shown in FIG. 6A is moved radially outward along the V-groove while bending the spring piece radially outward, and FIG. Sectional view along line VII-VII (A) is a figure which shows the state which the ball | bowl shown to Fig.7 (a) spreads the hole part and cutting | disconnection part of a spring piece, and passed to radial direction outward, (b) is a VIII-VIII of (a). Cross section along line

  1 and 2 show a pulley with a limiter according to an embodiment of the present invention. This pulley with a limiter includes a pulley 1, a hub 2 disposed at the center of the pulley 1, and a torque limiter 3 that transmits rotational torque from the pulley 1 to the hub 2.

  A drive belt 4 is wound around the outer periphery of the pulley 1. The drive belt 4 is connected to a crankshaft of an engine (not shown). When the engine is operated and the crankshaft rotates, the rotation of the crankshaft is transmitted to the pulley 1 via the drive belt 4. .

  The pulley 1 includes a cylindrical rim portion 6 having a circumferential groove 5 that engages with the drive belt 4 on the outer periphery, a cylindrical boss portion 7 disposed inside the rim portion 6, a rim portion 6, and a boss portion 7. And a connecting portion 8 for connecting the two. The rim part 6, the boss part 7, and the connecting part 8 are integrally formed of resin. A rolling bearing 9 that rotatably supports the pulley 1 is attached to the inner periphery of the boss portion 7. Inside the rolling bearing 9 is provided a cylindrical support shaft 11 that is fixed to an automobile auxiliary machine 10 (for example, a compressor for a car air conditioner). A metal nut 12 for fixing the torque limiter 3 is embedded in the connecting portion 8.

  The hub 2 is fixed to the shaft end portion of the driven shaft 13 positioned at the rotation center of the pulley 1 with a bolt 14. The driven shaft 13 is a shaft that is rotationally driven by the driving belt 4 wound around the outer periphery of the pulley 1, and the automobile auxiliary machine 10 is driven by the rotational force of the driven shaft 13 as power. The hub 2 includes a spline cylinder portion 15 that fits a spline formed on the outer periphery of the shaft end portion of the driven shaft 13, and a flange portion 16 that is integrally formed on the outer periphery of the spline cylinder portion 15.

  The torque limiter 3 is formed on the outer periphery of the first annular plate 21, the second annular plate 22 provided to face the first annular plate 21 in the axial direction, and the flange portion 16 of the hub 2. And a ball 24 accommodated in the V-groove 23. The first annular plate 21 and the second annular plate 22 are both formed of a metal plate and are fixed to the side surface of the pulley 1 with bolts 25. A plurality of V grooves 23 are provided at intervals in the circumferential direction, and a plurality of balls 24 are also provided correspondingly.

  The first annular plate 21 has a flat plate shape that is orthogonal to the axial direction as a whole. The second annular plate 22 is spaced apart from the outer flat plate portion 26 fixed to the outer diameter side portion of the first annular plate 21 and the inner diameter side portion of the first annular plate 21 in the axial direction. The inner flat plate portion 27 arranged in parallel, the outer cylindrical portion 28 connecting the radial inner end of the outer flat plate portion 26 and the radial outer end of the inner flat plate portion 27, and the radial inner end of the inner flat plate portion 27. And an inner cylindrical portion 29 extending in the axial direction toward the first annular plate 21 (see FIG. 5).

  As shown in FIG. 3, the V-groove 23 is a groove having a V-shaped cross section orthogonal to the axial direction, and is formed so that the radial depth gradually decreases from the center in the circumferential direction toward both sides in the circumferential direction. ing. As the V-groove 23, for example, a groove whose cross-sectional shape orthogonal to the axial direction becomes two straight lines that intersect at an angle in the range of 30 ° to 50 ° can be adopted. The ball 24 has an outer diameter large enough to protrude from the V groove 23 to the outer diameter side in a state of being accommodated in the deepest position of the V groove 23. The ball 24 is made of steel.

  As shown in FIG. 2, the second annular plate 22 has a plurality of pairs of slits 30 corresponding to the number of balls 24. Each pair of slits 30 is composed of two slits positioned at intervals in the circumferential direction.

  As shown in FIG. 5, each pair of slits 30 crosses the inner cylindrical portion 29 in the axial direction, and further extends radially outward from the boundary between the inner cylindrical portion 29 and the inner flat plate portion 27 in the inner flat plate portion 27. It is formed as follows. A spring piece 31 extending in the axial direction is formed in a portion between adjacent slits 30 of the inner cylindrical portion 29. The spring piece 31 is a portion that bends radially outward when the ball 24 (see FIG. 3) moves radially outward and applies a radially inward biasing force to the ball 24. The width of each slit 30 is set to be smaller than the outer diameter of the ball 24.

  As shown in FIG. 4, the spring piece 31 includes a hole portion 32 that fits into the ball 24 and a separation portion 33 that divides the circumference of the hole portion 32. The hole portion 32 has a circular edge having a smaller diameter than the outer diameter of the ball 24. The separating portion 33 is a cut that extends in the axial direction from the inner periphery of the hole portion 32 and opens to the tip of the spring piece 31.

  As shown in FIGS. 6A and 6B, the first annular plate 21 includes a stopper portion 34 (in the drawing, the first annular plate is located with a gap on the radially outer side of the spring piece 31). 21 in the radially inner end). The size of the gap between the spring piece 31 and the stopper portion 34 is narrower than the outer diameter of the ball 24. As shown in FIGS. 7A and 7B, the stopper portion 34 is a portion that receives the spring piece 31 and regulates the amount of deflection of the spring piece 31 when the spring piece 31 bends radially outward. .

  As shown in FIG. 1, between the opposing surfaces of the first annular plate 21 and the second annular plate 22 (in this embodiment, the inner diameter side portion of the first annular plate 21 and the second annular ring A ball housing portion 35 is formed in a space surrounded by the outer cylindrical portion 28, the inner flat plate portion 27, and the inner cylindrical portion 29 of the plate 22. The ball accommodating portion 35 is a space that receives the ball 24 when the ball 24 passes the spring piece 31 and moves radially outward.

  An example of using this pulley with a limiter will be described. The rotation of the crankshaft of the engine is transmitted to the pulley 1 via the drive belt 4, and when the pulley 1 rotates, the rotation of the pulley 1 is transmitted to the hub 2 via the torque limiter 3. Driven by rotation. Here, when the rotational load of the driven shaft 13 is in the normal range (that is, when the automobile auxiliary machine 10 is operating without being damaged), the torque limiter 3 transmits the rotational torque from the pulley 1 to the hub 2.

  At this time, as shown in FIGS. 7A and 7B, the ball 24 moves the spring piece 31 outward in the radial direction in accordance with the rotational torque acting between the pulley 1 (see FIG. 1) and the hub 2. While being deflected, it moves radially outward along the V-groove 23, and the pulley 1 (see FIG. 1) and the hub 2 are relatively displaced in the circumferential direction. Therefore, the fluctuation of the rotational load of the driven shaft 13 shown in FIG. 1 and the fluctuation of the rotational torque transmitted from the driving belt 4 to the pulley 1 can be absorbed between the pulley 1 and the hub 2 to obtain a damper action. Can do.

  Further, in the unlikely event that the automobile auxiliary machine 10 shown in FIG. 1 is damaged and the rotational load of the driven shaft 13 becomes excessive, as shown in FIGS. The hole portion 32 and the separation portion 33 of 31 are expanded and passed outward in the radial direction, and the ball 24 is received in the ball housing portion 35. In this state, since there is no ball 24 in the V-groove 23, transmission of rotational torque between the pulley 1 (see FIG. 1) and the hub 2 is interrupted. Thus, the torque limiter 3 shown in FIG. 1 idles the pulley 1 by interrupting transmission of rotational torque from the pulley 1 to the hub 2 when the rotational load of the driven shaft 13 becomes excessive. By protecting the drive belt 4, the vehicle can travel to the repair shop.

  This pulley with a limiter cuts off the transmission of rotational torque between the pulley 1 and the hub 2 when the automobile auxiliary machine 10 is damaged and the rotational load of the driven shaft 13 becomes excessive, and the drive belt 4 is Protect. Further, even if the pulley 1 rotates in this state, there is no portion that repeatedly collides with the rotation of the pulley 1, so that abnormal noise is unlikely to occur.

  In addition, this pulley with a limiter has a stopper portion 34 that receives the spring piece 31 and regulates the amount of deflection of the spring piece 31 when the spring piece 31 bends radially outward. It is possible to set a relatively large rotational torque at which the torque limiter 3 operates, while ensuring a damper action by moving along.

  Further, in this pulley with a limiter, since the slit 30 is formed so as to extend radially outward from the boundary between the inner cylindrical portion 29 and the inner flat plate portion 27, the spring piece 31 is elastically deformed. This makes it possible to obtain a damper action effectively.

  Further, in this pulley with a limiter, since the width of each slit 30 is set to be smaller than the outer diameter of the ball 24, when the ball accommodating portion 35 receives the ball 24, the ball 24 is slit. It is possible to prevent dropping through 30.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 1 Pulley 2 Hub 3 Torque limiter 4 Drive belt 13 Driven shaft 21 1st ring plate 22 2nd ring plate 23 V groove 24 Ball 27 Inner flat plate part 29 Inner cylindrical part 30 Slit 31 Spring piece 32 Hole part 33 Separation part 34 Stopper part 35 Ball housing part

Claims (6)

A pulley (1) around which a drive belt (4) is wound;
A hub (2) fixed to a shaft end of a driven shaft (13) located at the rotation center of the pulley (1);
When the rotational load of the driven shaft (13) is in the normal range, rotational torque is transmitted from the pulley (1) to the hub (2), and the rotational load of the driven shaft (13) becomes excessive. Is a torque limiter (3) for interrupting transmission of rotational torque from the pulley (1) to the hub (2);
In a pulley with a limiter having
The torque limiter (3)
A V-groove (23) provided on the outer periphery of the hub (2) such that the radial depth gradually decreases from the circumferential center toward both sides in the circumferential direction;
A ball (24) housed in the V-groove (23);
It has a hole (32) that fits into the ball (24) and a cut-out part (33) that divides the circumference of the hole (32), and the ball (24) moves radially outward. A spring piece (31) that flexes radially outward when imparted to the ball (24) in a radially inward direction,
A ball receiving portion (35) for receiving the ball (24) when the ball (24) spreads the hole (32) and the separating portion (33) and passes radially outward;
A pulley with a limiter. The torque limiter (3)
The spring piece (31) is positioned with a gap on the outer side in the radial direction. When the spring piece (31) is bent outward in the radial direction, the spring piece (31) is received and the spring piece (31) is received. The pulley with a limiter according to claim 1, further comprising a stopper portion (34) that regulates a deflection amount of the limiter. The torque limiter (3)
A first annular plate (21) fixed to a side surface of the pulley (1);
A second annular plate (22) provided opposite to the first annular plate (21) in the axial direction;
The spring piece (31) is provided to extend in the axial direction at the radially inner end of the second annular plate (22),
The stopper portion (34) is provided at the radially inner end of the first annular plate (21),
The pulley with a limiter according to claim 2, wherein the ball housing portion (35) is a space formed between opposing surfaces of the first annular plate (21) and the second annular plate (22).   The second annular plate (22) includes an inner flat plate portion (27) arranged in parallel with the first annular plate (21) at an interval in the axial direction, and an inner flat plate portion (27). An inner cylindrical portion (29) extending in the axial direction from the radially inner end of the first annular plate (21), and at least a pair of slits formed across the inner cylindrical portion (29) in the axial direction The pulley with a limiter according to claim 3, wherein the spring piece (31) is formed between the pair of slits (30).   The at least one pair of slits (30) are formed to extend radially outward from the boundary between the inner cylindrical portion (29) and the inner flat plate portion (27) in the inner flat plate portion (27). The pulley with a limiter according to claim 4.   The pulley with a limiter according to claim 4 or 5, wherein a width of each slit (30) of the at least one pair of slits (30) is set to be smaller than an outer diameter of the ball (24).

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