JP2013160266A - One-way clutch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a one-way clutch that is compact, has large allowable torque and has superior productivity.SOLUTION: A one-way clutch 10 includes an outer ring 12, an inner ring 20 and a cam cage 30. The cam cage 30 includes a pair of cage rings 32, 32 and in the cage ring 32, a stopper part 32a for stopping swirling of a cam 38 is formed integrally. Therefore, the number of components is reduced, a space of the cam cage 30 in a circumferential direction can be secured and the cam 38 can be provided additionally.

Description

  The present invention relates to a centrifugal lift-off type one-way clutch.

A centrifugal lift-off type one-way clutch (hereinafter simply referred to as “one-way clutch”) includes an inner ring, a cam cage attached to the inner ring, a cam pivotally supported by the cam cage, and an outer ring. , Are designed to rotate in the same direction. When the one-way clutch is assembled, a plurality of cams biased by a torsion coil spring are in contact with each other so as to be pressed against the outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring. When the drive shaft connected to the inner ring rotates in one direction, the cam slides on the inner peripheral surface of the outer ring, so that the inner ring idles with respect to the outer ring. When the drive shaft rotates at a high speed in the same direction, the centrifugal force acts against the urging direction of the torsion coil spring against the center of gravity of the cam at a position eccentric from the center of the shaft supporting the cam. Acting beyond the force, the cam rotates and a gap is created between the cam and the outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring, so that the cam and the outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring rub against each other. Instead, the inner ring is idle with respect to the outer ring. At this time, the rotation of the cam is stopped by the stopper portion at a position where the cam can maintain a non-contact state with the outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring. Since the cam is biased by the torsion coil spring, when the drive shaft is slowed down or stopped, it returns to the assembled state. On the other hand, when the drive shaft tries to rotate in the opposite direction, torque in the same direction as the biasing direction of the biasing member acts on the cam due to friction with the inner peripheral surface of the outer ring, and the cam acts on the outer peripheral surface of the inner ring and the outer ring. Because of the friction between the cam and the outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring, torque from the drive shaft is transmitted to the outer ring through the inner ring and the cam. Hereinafter, for convenience of explanation, a case where torque is transmitted from the inner ring to the outer ring is referred to as an “on state”, and a case where the inner ring rotates idly with respect to the outer ring is referred to as an “off state”.
The centrifugal lift-off type one-way clutch can be roughly divided into two applications. First, the inner ring is connected to the drive shaft and the outer ring is connected to the driven shaft, and is turned on during normal operation, and torque is transmitted from the inner ring to the outer ring, while the drive shaft connected to the inner ring rotates in reverse. Or when the driven shaft connected to the outer ring is in an overrun state and is turned off so that torque is not transmitted between the inner ring and the outer ring. The second is that the inner ring is connected to the drive shaft of the machinery, the outer ring is fixed so that it cannot rotate, and the drive shaft can be rotated in the off state during normal operation, while it is on when the drive shaft is stopped. This is a case where the drive shaft is used to prevent reverse rotation due to an external force. Specific examples include usage examples in ski lifts and inclined conveyors.
Centrifugal lift-off type one-way clutch, when the drive shaft rotates at a high speed in the off state, a gap is generated between the cam and the inner surface of the outer ring and the outer surface of the inner ring due to the centrifugal force. Wear and seizure due to the friction, and the allowable torque in the ON state (hereinafter sometimes simply referred to as “allowable torque”) is larger than that of other one-way clutches such as a roller free wheel. There is an advantage.
Examples of such a centrifugal lift-off type one-way clutch include the following.

JP 49-13551 A JP-A-9-151964

In the one-way clutch disclosed in Patent Document 1, cam cages that frictionally engage with an inner ring are provided on both sides of a cam, and an interposing disk is interposed between the cam and the cam cage, and a bolt that passes through these cam cages. The cam is pivotally supported, and the cam is biased by a torsion coil spring in a direction to engage the inner ring and the outer ring. A spring ring is fitted in the groove of the inner ring to prevent the cam cage from moving in the axial direction. The operation when the drive shaft connected to the inner ring rotates is as described above. When the drive shaft rotates at a high speed in the off state, the cam rotates until it comes into contact with the pin on which the end of the torsion coil spring is hung by centrifugal force. That is, the pin plays the role of a stopper portion.
In the one-way clutch disclosed in Patent Document 2, a rotation synchronization pin is provided as a rotation synchronization portion on the outside of the cam cage so as to engage with a retaining ring fitted in a groove provided in the inner ring. The pin for rotation synchronization is located. When the drive shaft connected to the inner ring rotates, the retaining ring hits the rotation synchronization pin, so that torque in the same direction as the drive shaft is transmitted to the cam cage. The cam pivotally supported by the cam cage is biased by a torsion coil spring in a direction to engage the inner ring and the outer ring. The operation when the drive shaft connected to the inner ring rotates is as described above. When the drive shaft rotates at a high speed in the off state, the cam rotates by centrifugal force until it comes into contact with a stopper shaft provided on the cam cage and on which the end of the torsion coil spring is hung.

The one-way clutches of Patent Documents 1 and 2 require as many pins and stopper shafts as the number of each cam to stop the rotation of the cam when the drive shaft rotates at high speed in the off state. In addition to increasing manufacturing costs, there are problems in terms of compactness, increased assembly and maintenance man-hours, and weight. Furthermore, not only the cam shaft but also the holes for pins and stopper shafts must be provided in the cam cage, so that drilling and chamfering operations are required. In particular, the dish-shaped chamfering operation can be performed only one at a time, which requires processing costs and time. In addition, as in Patent Document 2, the fact that the rotation synchronization pin is provided separately from the cam cage also leads to an increase in the number of parts, which causes the above-described problem.
By the way, the allowable torque increases as the total length of contact between the cam, the inner ring, and the outer ring increases. Therefore, the allowable torque can be increased by increasing the number of cams or increasing the cam width. However, if the cam width is simply increased, the axial dimension of the one-way clutch will increase, and even if it is attempted to increase the number of cams, a large number of parts will require space for each part. Since it is not possible to secure a space for increasing the cam, it is difficult to increase the allowable torque without increasing the size.

  SUMMARY OF THE INVENTION In view of the above-described problems of the prior art, it is an object of the present invention to provide a one-way clutch that is compact, has a large allowable torque, and is excellent in productivity.

The present invention includes an outer ring,
An inner ring having two annular grooves parallel to the outer peripheral surface;
A retaining ring fitted in the annular groove;
A cam cage constituted by a pair of cage rings arranged side by side on the outer peripheral surface of the inner ring between the annular grooves and kept at a constant interval by a plurality of pins;
A cam pivotally supported by the cam cage and a torsion coil spring that urges the cam in a direction to engage the inner ring and the outer ring;
A rotation synchronization portion that is provided in the cage ring and that synchronizes the rotation of the inner ring and the cam cage and that engages with the retaining ring;
The above-mentioned problem is solved by a one-way clutch which is provided with a stopper portion which is integrally formed with the cage ring and stops the rotation of the cam.

  Further, it is preferable that the rotation synchronization portion is formed integrally with the cage ring, and it is preferable that the pin also serves as a stopper portion.

  According to the present invention, since the stopper portion for stopping the rotation of the cam when the drive shaft rotates at a high speed in the off state is integrally formed with the cage ring, the cage ring is separated from the conventional cage ring. No pins or stopper shafts are required. Accordingly, since the number of parts is reduced as compared with the conventional case, the manufacturing cost can be reduced, assembly and maintenance can be easily performed, and further, the weight can be reduced. In addition, it is not necessary to process the pin or stopper shaft hole into the cam cage, so that the number of processing steps, cost, and time can be reduced. Further, since a separate pin or stopper shaft is not required, the interval between the cams can be reduced, and the number of cams can be increased. Accordingly, it is possible to increase the allowable torque with a smaller axial dimension than in the prior art.

  Furthermore, if a rotation synchronization part that engages with a retaining ring that synchronizes the rotation of the inner ring and the cam cage is formed integrally with the cage ring, a separate unit for synchronizing the rotation of the inner ring and the cam cage as in the prior art is provided. Since a pin is unnecessary, the same effect as described above can be obtained. Further, if the pin also serves as the stopper portion, it is not necessary to provide a stopper portion where the pin is provided, so that the number of processing steps can be reduced.

The front view showing the one way clutch of a first embodiment of the present invention. FIG. 2 is a longitudinal sectional view taken along line 2-2 in FIG. 1. The front view of the torsion coil spring used for a one-way clutch. The front view in case the cam cage is attached to the inner ring | wheel of the one-way clutch of 1st embodiment of this invention. The front view (part sectional drawing) of the cam cage of the one-way clutch of 1st embodiment of this invention. The enlarged view of A of FIG. The enlarged view of B of FIG. The principal part enlarged view (partial sectional view) of the cam cage of the one-way clutch of the second embodiment of the present invention. The principal part enlarged view (part sectional drawing) of the cam cage of the one-way clutch of 3rd embodiment of this invention. The front view (part sectional drawing) of the cam cage of the conventional one-way clutch. The figure which compared the dimension of the axial direction of the one-way clutch of this invention, and the conventional one-way clutch.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. However, the present invention is not limited to this embodiment.

  A one-way clutch 10 shown in FIG. 1 according to the first embodiment of the present invention includes an outer ring 12, an inner ring 20, and a cam cage 30. In FIG. 1, the detailed illustration of the cam cage 30 is omitted. The inner ring 20 has a shaft hole 22, and a drive shaft (not shown) is inserted into the shaft hole 22 and is key-fastened. Needless to say, the drive shaft and the inner ring 20 may be connected by a method other than key fastening. On the other hand, the outer ring 12 is connected to a driven shaft (not shown) or fixed so as not to rotate.

  2 is a longitudinal sectional view taken along line 2-2 of FIG. A cam cage 30 is located between the outer ring 12 and the inner ring 20. The cam cage 30 is configured by cage pins 32, 32 arranged in parallel on the outer peripheral surface 24 between two parallel annular grooves 26, 26 of the inner ring 20 being kept constant by pins 34. ing. The pin 34 is attached to the cage rings 32, 32 by bolts 35, 35 at several places (three places in FIG. 4), and the retaining rings 28, 28 are provided in the annular grooves 26, 26 formed in the inner ring 20. Since the cam cage 30 is prevented from moving in the axial direction by being fitted, the cam cage 30 is attached so as not to be detached from the inner ring 20. The cage ring 32 is not limited to a material cut from iron or steel, and may be a material that is press-worked. If the material satisfies the strength, the cage ring 32 may be a resin such as engineering plastic or a non-ferrous material such as aluminum. May be used.

  The cam cage 30 includes a cam 38 pivotally supported by the cage rings 32 and 32 and a torsion coil spring 39 that urges the cam 38 in a direction to engage with the inner ring 20 and the outer ring 12. The spring 39 biases the cam 38 to be pressed against the outer peripheral surface 24 of the inner ring 20 and the inner peripheral surface 14 of the outer ring 12. The support shaft 36 of the cam 38 may be formed integrally with the cam 38 as a trunnion, in addition to the shaft passing through the cam 38 as shown in FIG. The torsion coil spring 39 has a shape as shown in FIG. 3A, and is provided so that one coil portion 39a is positioned on one side of the cam. The torsion coil spring 39c as shown in b) may be used so that the two coil portions 39d and 39d are positioned on both sides of the cam. Note that it is preferable to use a torsion coil spring 39 having one coil portion 39a as shown in (a) because the space between the cage rings 32, 32 can be secured. In the torsion coil spring 39, for example, one end 39b is hung on a latching recess 32e (see FIG. 5) provided on the inner peripheral side of the cage ring 32, and the other end 39b is hung on a cam 38. The cam 38 is biased in a direction to engage with the inner ring 20 and the outer ring 12. On the other hand, in the torsion coil spring 39c, for example, the end portions 39e and 39e are hooked on the hooking recess 32e (see FIG. 5) of the adjacent cage ring 32, the connecting portion 39f is hooked on the cam, and the cam 38 is mounted on the inner ring 20. And urged in a direction to engage with the outer ring 12.

  Next, as shown in FIG. 2, the retaining rings 28 and 28 are attached so as to be in close contact with the annular groove 26 due to its elasticity. Here, as shown in FIG. 4, the engaging portion 28 a of the retaining ring 28 is provided with a rotation synchronization portion 32 b that is integrally formed with the cage ring 32 and bent in the direction of the annular groove 26 (see FIG. 2). Therefore, when the inner ring 20 rotates, the engaging portion 28a of the retaining ring 28 hits the rotation synchronizing portion 32b, and torque in the same direction as the inner ring 20 is transmitted to the cam cage 30. The rotation synchronization portion 32b is formed in the cage ring 32 as described above, and then processed so as to be a protrusion protruding in the direction of the annular groove 26. You may form so that it may become the protrusion which protrudes in the groove | channel 26 direction. Further, the engagement portion 28a between the rotation synchronization portion 32b and the retaining ring 28 is not limited to the notch portion as in the case of the retaining ring 28, and if the rotation synchronization portion 32b can be engaged with the retaining ring, It can be changed according to the shape. Further, in the case of the cam cage 30, the rotation synchronization portion 32 b is provided in an inner peripheral recess 32 c provided on the inner peripheral side of the cage ring 32, as shown in FIG. At least one of them may be bent in the direction of the annular groove 26. As described above, the cage ring 32 can be reduced in weight by providing the inner peripheral side recess 32c. Note that a plurality of inner peripheral recesses 32c and rotation synchronization portions 32b may be provided according to the shape of the retaining ring.

  Further, the outer peripheral side of the cage ring 32 is provided with the same number of outer peripheral recesses 32d as the cam 38, and the outer peripheral recess 32d is provided with a protruding stopper 32a. In the stopper portion 32a, at least one of the pair of cage rings 32, 32 is bent in the cam 38 direction. In this way, the cage ring 32 can be reduced in weight by providing the outer peripheral side recess 32d. The stopper portion 32a is formed integrally with the cage ring 32 as described above, and then processed so as to be a protrusion protruding in the cam 38 direction. You may form so that it may become the processus | protrusion which protrudes.

  As described above, the cam 38 is biased by the torsion coil spring 39 in the direction in which the cam 38 is engaged with the inner ring 20 and the outer ring 12, so that the state shown in FIG. 5A, that is, the inner peripheral surface 14 of the outer ring 12 and It will be in the state pressed against the outer peripheral surface 24 of the inner ring | wheel 20. FIG. 6 is a partially enlarged view showing the state A of FIG. The center of gravity G of the cam 38 is at a position eccentric from the center of the support shaft 36, and the cam 38 is urged in the counterclockwise direction by a torsion coil spring 39. When a drive shaft (not shown) rotates counterclockwise, torque in the counterclockwise direction is transmitted to the inner ring 20 and the cam cage 30 as well. Here, the dimension of the cam 38 is designed so that it can be rotated only in one direction (right rotation direction) from the assembled state, and because it is in contact with the inner peripheral surface 14 of the outer ring 12, The friction with the inner peripheral surface 14 of the outer ring 12 tends to rotate in the clockwise direction around the support shaft 36. Therefore, since the cam 38 slides on the inner peripheral surface 14 of the outer ring 12, when the drive shaft rotates counterclockwise, it is turned off.

  On the other hand, as shown by the arrow in FIG. 6, when the drive shaft rotates to the right, the cam 38 is in contact with the inner peripheral surface 14 of the outer ring 12, so that the support shaft 36 is caused by friction with the inner peripheral surface 14 of the outer ring 12. Attempts to rotate counterclockwise around the center. For this reason, the cam 38 is further pressed against the inner peripheral surface 14 of the outer ring 12 and the outer peripheral surface 24 of the inner ring 20 and cannot rotate, so that the cam 38 is turned on when the drive shaft rotates clockwise.

  Next, when the drive shaft rotates at high speed in the off state, the cam 38 is in the state of B in FIG. FIG. 7 is a partially enlarged view of the state B. When the drive shaft rotates at a high speed, the centrifugal force in the F direction acts on the center of gravity G of the cam 38 beyond the elastic force of the torsion coil spring 39, so the cam 38 rotates until it comes into contact with the stopper portion 32a. At this time, a gap is generated between the cam 38 and the outer peripheral surface 24 of the inner ring 20 and the inner peripheral surface 14 of the outer ring 12. Therefore, since the cam 38 does not contact the outer peripheral surface 24 of the inner ring 20 and the inner peripheral surface 14 of the outer ring 12, heat generation due to these frictions can be prevented, and wear and seizure of parts can be prevented. Since the cam 38 is biased by the torsion coil spring 39 in a direction to engage with the inner ring 20 and the outer ring 12, when the rotation of the drive shaft becomes low speed or stops, the state shown in FIG. Return.

  As shown in FIG. 8, if one end 39b of the torsion coil spring 39 (see FIG. 3A) is hung on the stopper 32a, a latching recess 32e (see FIG. 4) is provided. Since there is no need, the processing man-hours and costs can be reduced. It should be noted that one end 39b of the torsion coil spring 39 may be fixed by a method such as winding around the stopper portion 32a. When using the torsion coil spring 39c (see FIG. 3B), the end portions 39e and 39e may be hung on the stopper portion 32a.

  Further, as shown in FIG. 9, if the pin 34 is configured to also serve as the stopper portion 32a, it is not necessary to provide the stopper portion 32a where the pin 34 is provided, so that the number of processing steps and costs can be reduced. The configuration in which the end portion of the torsion coil spring is hung on the stopper portion 32a and the configuration in which the pin 34 also serves as the stopper portion 32a may be combined. In this case, the end portion of the torsion coil spring is hung on the pin 34. Can do.

  Next, FIG. 10 is a front view (partially sectional view) of a cam cage 130 of a conventional one-way clutch as disclosed in Patent Document 2. FIG. The diameter of the cam cage 130 is the same as that of the cam cage 30 shown in FIG. The cam cage 130 includes a support shaft 136 on the cage ring 132, a pin 134 fixed by a countersunk bolt 135, and a rotation synchronization pin 131 that is a rotation synchronization portion that engages with an engagement portion of a retaining ring (not shown). It is. The cam 138 is biased by a torsion coil spring 139 having two coil portions 139a and 139a (see FIG. 11). The connection portion of the torsion coil spring 139 is connected to the cam 138 and the end portion 139b is connected to the pin 134. It is hung.

  Next, FIG. 11 is a diagram comparing axial dimensions of a conventional cam cage 130 and the cam cages 30 and 30a of the present invention. In the conventional cam cage 130, the head of the countersunk bolt provided in the cage ring 128 is embedded in the cage ring 128, while in the cam cage 30, 30a of the present invention, the head of the bolt 35 is the cage rings 28, 28a. Therefore, the axial dimension of the cam cage 130 including the cage rings 128 and 128 and the axial dimension of the cam cage 30 and 30a including the head of the bolt 35 are compared. Here, (a) shows a conventional cam cage 130, (b) shows the same cage ring thickness, cam width and number as in (a), and a torsion coil spring 39 with one coil portion. (C) is the same as (a) in the case (c) where the number of cams is increased by one from the configuration of (b) and the cam contacts the outer peripheral surface of the inner ring or the inner peripheral surface of the outer ring. (D) is the same cam width and number as in (a), the cage ring is made thinner than (a), and a torsion coil spring 39 with one coil portion is used. In the case (e), the number of cams is increased by one from the configuration of (d), and the total length of the cam contacting the outer peripheral surface of the inner ring or the inner peripheral surface of the outer ring is the same as (a). It represents the case of.

  In the case of (b), a space can be secured for one torsion coil part 139a of (a). In the case of (c), in addition to the case of (b), one cam 39 can be added. The dimension in the axial direction per 39 can be reduced. Further, in the case of (d), in addition to the case of (b), a space can be secured by thinning the cage ring 28a. In the case of (e), the cam 39 is added to the case of (d). As much as one can be added, the axial dimension of one cam 39 can be reduced. Therefore, when the axial dimensions of the entire cam cage in FIGS. 11A to 11E are A, B, C, D, and E, A> B> C> D> E. Therefore, by adopting the configuration of the present invention, it is possible to reduce the size or increase the allowable torque as compared with the conventional case. Further, if the thin cage ring 28a is used, it is possible to further reduce the size or increase the allowable torque. be able to.

  As described above, according to the present invention, the space in the circumferential direction of the cam cage of the one-way clutch can be secured and the number of cams can be increased by reducing the number of parts. It is possible to provide an excellent one-way clutch.

DESCRIPTION OF SYMBOLS 10 One-way clutch 12 Outer ring 20 Inner ring 24 Outer surface of inner ring 26 Annular groove 28 Retaining ring 28a Engagement part of retaining ring 30 Cam cage 32 Cage ring 32a Stopper part 32b Rotation synchronization part 32c Inner peripheral side concave part 32d Outer peripheral side concave part 34 Pin 38 Cam 39 Torsion coil spring

Claims (3)

Outer ring,
An inner ring having two annular grooves parallel to the outer peripheral surface;
A retaining ring fitted in the annular groove;
A cam cage constituted by a pair of cage rings arranged side by side on the outer peripheral surface of the inner ring between the annular grooves and kept at a constant interval by a plurality of pins;
A cam pivotally supported by the cam cage and a torsion coil spring that urges the cam in a direction to engage the inner ring and the outer ring;
A rotation synchronization portion that is provided in the cage ring and that synchronizes the rotation of the inner ring and the cam cage and that engages with the retaining ring;
It is provided with a stopper part that is integrally formed with the cage ring and stops the rotation of the cam.
One way clutch.   The one-way clutch according to claim 1, wherein the rotation synchronization portion is integrally formed with the cage ring.   The one-way clutch according to claim 1 or 2, wherein the pin also serves as the stopper portion.

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