JP2006336838A - Reverse input cutoff clutch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely prevent the successive generation of abnormal sound and vibrations without causing the rotation loss and deterioration of clutch function at the time of driving. <P>SOLUTION: The reverse input cutoff clutch is equipped with an input shaft 11 in which rotation torque is input, an output shaft 12 out of which the rotation torque is output, an outer ring 13 restricted in the rotation, a torque transmission means 21 which is provided between the input shaft 11 and output shaft 12 and which transmits input torque from the input shaft 11 to the output shaft 12, and a locking means 22 which is provided between the outer ring 13 and the output shaft 12 and which locks the output shaft 12 and the outer ring 13 with respect to the torque reversely input from the output shaft 12 and cuts off the transmission of the torque to the input shaft 11. In the loading of the input torque, the locking condition of the output shaft 12 and the outer ring 13 by the locking means 22 is released, and then the input torque is transmitted to the output shaft 12 by the torque transmitting means 21. The viscous fluid 27 which imparts rotational resistance varying in accordance with relatively rotating states of both input shaft 11 and output shaft 12 is sealed between the input shaft 11 and output shaft 12. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a reverse input cutoff clutch that is incorporated in, for example, an automobile steering device and has both a function of transmitting rotational torque from the input side to the output side and a function of blocking reverse input torque from the output side.

  For example, FIG. 6 and FIG. 7 show a structure example of a reverse input cutoff clutch incorporated in a steering apparatus of an automobile. The reverse input cutoff clutch shown in FIG. 1 is an input shaft (cage) 1 as an input side member to which rotational torque is input, and an output side member that is arranged coaxially with the input shaft 1 and outputs rotational torque. As an output shaft 2, an outer ring 3 as a stationary member that is coaxially disposed on the outer peripheral side of the input shaft 1 and the output shaft 2, and whose rotation is restricted, and a cam surface formed on the outer peripheral surface of the output shaft 2 2a and a pair of rollers 5 as an engaging member interposed in a wedge clearance 4 formed between the outer ring 3 and the inner peripheral surface 3a of the outer ring 3 so as to be engageable and disengageable, and an elastic force in a direction to separate the pair of rollers 5 from each other A spring 6 as an elastic member for urging the shaft, and a torque transmission means that is implanted on the outer periphery of the output shaft 2 so as to protrude in the radial direction and is inserted into a hole 7 formed in a part of the input shaft 1. (See, for example, Patent Documents 1 and 2)

  In this reverse input shut-off clutch, when a reverse input torque from the output shaft 2 is applied, a pair of rollers 5 urged in a direction away from each other by the spring 6 are engaged with the wedge gap 4 and By engaging with the outer ring 3, the output shaft 2 is locked with respect to the stationary outer ring 3, and as a result, reverse input torque is not transmitted to the input shaft 1.

On the other hand, when the input torque from the input shaft 1 is loaded, the input shaft 1 presses one of the pair of rollers 5 in a direction of separating from the wedge gap 4 against the elastic force of the spring 6. Therefore, after the locked state described above is released and the input shaft 1 is engaged with the pin 8 of the output shaft 2 after the locked state is released, the input torque is directly applied to the output shaft 2 via the pin 8. Communicated.
JP 2003-294060 A Japanese Patent Laid-Open No. 2004-19726

  By the way, in the above-described reverse input cutoff clutch, when input torque is applied to the input shaft 1, the locked state due to the roller engagement caused by the previous reverse input torque is released and then the input shaft 1 is connected via the pin 8. Thus, torque transmission to the output shaft 2 is performed. Therefore, a clearance m in the rotational direction is set between the pin 8 provided on the output shaft 2 and the hole 7 of the input shaft 1 into which the pin 8 is inserted so as to allow the release of the locked state. . For this reason, there is a slight time lag from when the load of the input torque is started until the input torque is actually transmitted to the output shaft 2.

  When the input torque and the reverse input torque act on the output shaft 2 in the same direction, when the rotational speed of the output shaft 2 due to the reverse input torque is larger than the rotational speed of the input shaft 1 due to the input torque, Immediately after unlocking due to input torque, the output shaft 2 is in a free state until the input shaft 1 contacts the pin 8.

  Here, if the rotational speed of the input shaft 1 is larger than the rotational speed of the output shaft 2, the input shaft 1 contacts the pin 8 as it is, and the input torque is transmitted from the input side to the output side. If the rotational speed of the output shaft 2 is larger than the rotational speed of the output shaft 2, the output shaft 2 rotates greatly before the input shaft 1 contacts the pin 8 and is locked again.

  In this case, since the rotation of the output shaft 2 is temporarily stopped, the locked state is released again by the input torque from the input shaft 1. Thereafter, the unlocked state and the relocked state are alternately repeated in a short time, and therefore, there is a possibility that continuous abnormal noise or vibration is generated inside the clutch.

  In order to solve this problem, in the reverse input cutoff clutch disclosed in Patent Document 1, a friction resistance is provided between the stationary system and the output shaft, and the input is performed by applying a brake to the output side when the roller is disengaged. The rotation speed is reduced with respect to the side. In the reverse input cutoff clutch disclosed in Patent Document 2, a frictional resistance is provided between the input shaft and the output shaft, and a rotational resistance is applied from the input side to the output side when the roller is disengaged. .

  However, the reverse input cutoff clutch disclosed in Patent Document 1 has a problem in that a loss due to the rotational resistance occurs during driving from the input side because the rotational resistance is always applied from the stationary system to the output side. Further, in the reverse input cutoff clutch disclosed in Patent Document 2, since rotational resistance is applied between the input shaft and the output shaft, this frictional resistance is a resistance that does not hinder the relative rotation of the input shaft and the output shaft. Therefore, if the rotational resistance to the output shaft is insufficient, or if the rotational resistance is too large, it is difficult to sufficiently function as a clutch.

  Therefore, the present invention has been proposed in view of the above-described problems, and the object of the present invention is to generate continuous abnormal noise and vibration without causing rotation loss during driving and lowering of the clutch function. It is an object of the present invention to provide a reverse input shut-off clutch that can surely prevent the above-described problem.

  As technical means for achieving the above object, the present invention includes an input side member to which rotational torque is input, an output side member to which rotational torque is output, a stationary side member to which rotation is restricted, Torque transmitting means provided between the input side member and the output side member for transmitting input torque from the input side member to the output side member; provided between the stationary side member and the output side member; Locking means for locking the output side member and the stationary side member against reverse input torque from the member and blocking torque transmission to the input side member, and when the input torque is loaded, the output side member by the locking means In the reverse input cutoff clutch that releases the locked state between the stationary member and the stationary member, and transmits the input torque to the output member by the torque transmitting means, the relative relationship between the input member and the output member is In rotation Flip wherein the encapsulating viscous fluid to impart rotational resistance that varies.

  In the present invention, when input torque from the input side member is loaded, the viscous resistance of the viscous fluid is small at the start of rotation of the input side member, so the input side member can rotate relative to the output side member. Yes, it is possible to transmit the input torque to the output side member after releasing the locked state. On the other hand, when the input torque and the reverse input torque act on the output side member in the same direction, the rotation speed of the output side member due to the reverse input torque is greater than the rotation speed of the input side member due to the input torque. If it is large, the output side member starts to rotate suddenly at the moment when the input side member is rotated to release the lock. However, the sudden rotation of the output side member increases the viscous resistance due to the viscous fluid, and the lock release state ( While the input side member and the output side member maintain the phase angle to some extent, the output side member rotates the input side member. Thereby, since the re-lock state can be avoided, the unlocked state and the re-lock state are not repeated alternately.

  As the locking means in the above-described configuration, a structure including a wedge gap formed between the output side member and the stationary side member and an engagement element that can be engaged with the wedge gap is desirable. As the engagement element, either a roller or a sprag can be used.

  In addition, as a structure for sealing the viscous fluid, the input side member and the output side member are arranged coaxially, and a concave hole is formed in one of the opposing surfaces of the input side member or the output side member, and the other opposing surface It is desirable to have a structure in which protrusions are formed in the recesses, the protrusions are inserted and disposed through the gaps, and a viscous fluid is sealed in the gaps. In this structure, if a seal member is disposed between the inner diameter surface of the concave hole and the outer diameter surface of the protrusion, leakage of the viscous fluid can be reliably prevented.

  According to the present invention, the input torque and the reverse input torque are output between the input side member and the output side member by enclosing the viscous fluid that gives a rotational resistance that changes according to the relative rotational state of the two. When acting on the member in the same direction, the unlocked state and the re-locked state even when the output side member rotation speed by the reverse input torque is larger than the input side rotation speed by the input torque Can be prevented reliably, and the rotational resistance due to viscous fluid depends on the relative rotational state of the input side member and the output side member. Therefore, there is no rotation loss during driving and no deterioration of the clutch function.

  1 and 2 show an overall configuration of a reverse input cutoff clutch according to an embodiment of the present invention. The reverse input cutoff clutch shown in FIG. 1 is an input shaft 11 (cage) as an input side member to which rotational torque is input, and an output side member that is arranged coaxially with the input shaft 11 and that outputs rotational torque. Provided between the input shaft 11 and the output shaft 12, and the outer ring 13 as a stationary side member which is coaxially disposed on the outer peripheral side of the input shaft 11 and the output shaft 12 and whose rotation is restricted. The torque transmission means 21 for transmitting the input torque from the input shaft 11 to the output shaft 12 is provided between the outer ring 13 and the output shaft 12, and the output shaft 12 against the reverse input torque from the output shaft 12 Locking means 22 for locking the outer ring 13 and blocking torque transmission to the input shaft 11 is provided.

  The input shaft 11 is provided with a plurality of column portions 11a extending in the axial direction by expanding one end portion on the output shaft side, and a pair of rollers serving as an engaging member between the column portions 11a. 15 and a pocket 23 accommodating a spring 16 as an elastic member are formed in a state where one side in the axial direction is opened. One end of the input shaft 11 on the output shaft side functions as a cage for holding the pair of rollers 15 and the spring 16 at predetermined intervals in the circumferential direction by the pocket 23, and the other end of the input shaft 11. Is inputted with rotational torque.

  One end of the output shaft 12 is inserted into the inner peripheral side of the column portion 11a of the input shaft 11, and the cam surface 12a on which the roller 15 rolls on the outer peripheral surface facing the inner peripheral surface of the column portion 11a. A wedge gap 14 is formed between the cam surface 12a and the cylindrical inner peripheral surface 13a located at the axial center of the outer ring 13. A pair of rollers 15 interposed in the wedge gap 14 so as to be able to be engaged and disengaged, and a spring 16 that urges an elastic force in a direction to separate the pair of rollers 15 from each other constitute a lock means 22. Input torque from the input shaft 11 is output to the other end of the output shaft 12, or reverse input torque is loaded.

  A pin 18 is implanted on the outer periphery of the output shaft 12 so as to protrude in the radial direction, and a hole 17 into which the pin 18 is inserted is formed in one of the column portions 11 a of the input shaft 11. . The inner diameter of the hole 17 is set to be slightly larger than the outer diameter of the pin 18, and a predetermined gap n is provided in the rotation direction. In this reverse input shut-off clutch, when input torque is applied to the input shaft 11, the locked state due to roller engagement caused by the previous reverse input torque is released, and then the pin 18 is moved from the column portion 11 a of the input shaft 11. Torque is transmitted to the output shaft 12 through this. Therefore, the clearance n in the rotational direction between the pin 18 and the hole 17 is dimensioned so as to allow release of the locked state. The pin 18 of the output shaft 12 is inserted and arranged in the hole 17 of the column portion 11a of the input shaft 11, and the input shaft 11 and the output shaft 12 can be connected by the pin 18, so that the torque transmission means 21 is provided. It is composed.

  The outer ring 13 is connected to a stationary system such as a frame (not shown), and rolling bearings 24 and 25 are interposed between inner peripheral surfaces at both ends in the axial direction and outer peripheral surfaces of the input shaft 11 and the output shaft 12. . The rolling bearings 24 and 25 rotatably and coaxially support the input shaft 11 and the output shaft 12 with respect to the outer ring 13. Although the rolling bearings 24 and 25 are illustrated in the drawings, other bearings such as a sliding bearing can be used instead. Further, a spacer 26 is disposed between the column portion 11 a and the rolling bearing 25 in order to restrict the axial movement of the roller 15 in the pocket 23.

  In the reverse input cutoff clutch having the above-described configuration, a viscous fluid 27 that provides rotational resistance that changes in accordance with the relative rotational state between the input shaft 11 and the output shaft 12 is enclosed. As a structure for sealing the viscous fluid 27, a concave hole 11b is formed in the shaft end surface of the input shaft 11 facing the output shaft 12, and a protrusion 12b is coaxially formed on the shaft end surface of the output shaft 12 facing the input shaft 11. The protrusion 12b is inserted and disposed in the concave hole 11b through the gap 28, and the viscous fluid 27 is sealed in the gap 28. As this viscous fluid 27, for example, silicone oil can be used, but other viscous fluids other than silicone oil may be used.

  In this sealed structure of the viscous fluid 27, the inner diameter surface of the concave hole 11 b of the input shaft 11 and the outer diameter surface of the protrusion 12 b of the output shaft 12 are slidable by relative rotation of the input shaft 11 and the output shaft 12. A seal member 29 is disposed between the opening peripheral edge of the concave hole 11a and the root of the protrusion 12b. This reliably prevents leakage of the viscous fluid 27 sealed in the gap 28 between the concave hole 11b and the protrusion 12b.

  In this embodiment, the case where the concave hole 11b is formed on the shaft end surface of the input shaft 11 and the projection 12b is formed on the shaft end surface of the output shaft 12 is illustrated, but conversely, the concave portion is formed on the shaft end surface of the output shaft 12. A hole may be formed, and a protrusion may be formed on the shaft end surface of the input shaft 11.

  In the neutral state shown in FIG. 3, for example, when a clockwise reverse input torque is input to the output shaft 12 (no input torque is applied to the input shaft 11), the counterclockwise direction ( A roller 15 positioned rearward in the rotational direction is engaged with and engaged with a wedge gap 14 between the output shaft 12 and the outer ring 13 by a spring 16 that biases a separation force between the rollers 15. Is locked clockwise with respect to the outer ring 13. On the other hand, when counterclockwise reverse input torque is input to the output shaft 12, the roller 15 positioned in the clockwise direction (backward in the rotational direction) is engaged with the wedge gap 14, and the output shaft 12 is engaged with the outer ring 13. Is locked counterclockwise. Therefore, the reverse input torque from the output shaft 12 is locked in both forward and reverse rotation directions, and no torque is transmitted to the input shaft 11.

  FIG. 4 shows a state in which the input shaft 11 starts to rotate counterclockwise by the input torque acting on the input shaft 11. The side surface of the pillar portion 11a of the pocket 23 positioned in the clockwise direction (backward in the rotation direction) of the input shaft 11 is engaged with the roller 15 positioned in the clockwise direction (backward in the rotation direction), and this is used as the elastic force of the spring 16. Resist and press counterclockwise (forward in the direction of rotation). As a result, the roller 15 positioned in the clockwise direction (rear in the rotational direction) is separated from the wedge gap 14 between the output shaft 12 and the outer ring 13 and can idle, and the locked state of the output shaft 12 is released (the counterclockwise state) The direction roller 15 does not engage with the wedge gap 14 between the output shaft 12 and the outer ring 13 and does not engage therewith). Accordingly, the output shaft 12 can rotate counterclockwise.

  When the input shaft 11 further rotates counterclockwise, the pin 18 of the output shaft 12 engages with the hole 17 of the column portion 11a of the input shaft 11 in the rotational direction as shown in FIG. Thereby, the counterclockwise input torque from the input shaft 11 is directly transmitted to the output shaft 12 via the pin 18, and the output shaft 12 rotates counterclockwise. When the clockwise input torque is input to the input shaft 11, the output shaft 12 rotates in the clockwise direction by the reverse operation to the above. Therefore, the input torque in the forward / reverse rotation direction from the input shaft 11 is transmitted to the output shaft 12 via the pin 18 as the torque transmission means 21, and the output shaft 12 rotates in both forward and reverse rotation directions. When the input torque from the input shaft 11 disappears, the spring 16 returns to the neutral position shown in FIG.

  The reverse input cutoff clutch of this embodiment has a structure in which the viscous fluid 27 is sealed between the input shaft 11 and the output shaft 12 as described above. As a result, when the input torque is continuously applied to the input shaft 11 by a rotational drive source such as a motor, the rotational speed is slow immediately after the start of the rotation. Therefore, when the input shaft 11 starts to rotate, the viscous resistance of the viscous fluid 27 is reduced. Since it is small, the input shaft 11 can rotate relative to the output shaft 12, and the input torque can be transmitted to the output shaft 12 after the lock state is released.

  On the other hand, when the input torque and the reverse input torque act on the output shaft 12 in the same direction, the rotational speed of the output shaft 12 due to the reverse input torque is greater than the rotational speed of the input shaft 11 due to the input torque. When the input shaft 11 is rotated and the lock is released, the output shaft 12 starts to rotate abruptly. However, the sudden rotation of the output shaft 12 increases the viscous resistance due to the viscous fluid 27, and the lock is released. The output shaft 12 rotates with the input shaft 11 in the state (the state in which the input shaft 11 and the output shaft 12 maintain the phase angle to some extent). Thereby, since the re-lock state can be avoided, the unlocked state and the re-lock state are not repeated alternately, and no continuous abnormal noise or vibration is generated.

FIG. 3 is a cross-sectional view taken along line BB in FIG. 2 in the embodiment of the reverse input cutoff clutch according to the present invention. It is sectional drawing which follows the AA line of FIG. FIG. 3 is a cross-sectional view illustrating an operation of the reverse input cutoff clutch of FIG. 2 and showing a locked state of the output shaft. FIG. 3 is a cross-sectional view illustrating an unlocked state of an output shaft for explaining the operation of the reverse input cutoff clutch of FIG. 2. FIG. 3 is a cross-sectional view illustrating a rotation state of an output shaft for explaining an operation of the reverse input cutoff clutch of FIG. 2. FIG. 8 is a cross-sectional view taken along line DD of FIG. 7 in a conventional example of a reverse input cutoff clutch. It is sectional drawing which follows the CC line of FIG.

Explanation of symbols

11 Input side member (input shaft)
11b Concave hole 12 Output side member (output shaft)
12b Protrusion 13 Stationary side member (outer ring)
14 Wedge clearance 15 Engagement element (roller)
21 Torque transmitting means 22 Locking means 27 Viscous fluid 28 Clearance 29 Seal member

Claims (5)

An input side member provided between an input side member to which rotational torque is input, an output side member from which rotational torque is output, a stationary side member to which rotation is restricted, and the input side member and the output side member. Torque transmission means for transmitting the input torque from the output side member to the output side member, and the output side member and the stationary side member with respect to the reverse input torque from the output side member. And locking means for blocking torque transmission to the input side member, and when the input torque is applied, the locked state between the output side member and the stationary side member by the locking means is released, and then the torque transmission is performed. In the reverse input cutoff clutch that transmits the input torque to the output side member by means,
A reverse input shut-off clutch characterized in that a viscous fluid that imparts a rotational resistance that changes in accordance with the relative rotational state of the input side member and the output side member is enclosed.   2. The reverse input cutoff clutch according to claim 1, wherein the lock means includes a wedge gap formed between the output side member and the stationary side member, and an engagement element engageable with the wedge gap.   The input side member and the output side member are arranged on the same axis, and a concave hole is formed on one opposing surface of the input side member or the output side member, and a projection is formed on the other opposing surface, The reverse input cutoff clutch according to claim 1 or 2, wherein a protrusion is inserted and disposed through a gap, and a viscous fluid is sealed in the gap.   The reverse input cutoff clutch according to claim 3, wherein a seal member is disposed between the inner diameter surface of the concave hole and the outer diameter surface of the protrusion.   The reverse input cutoff clutch according to any one of claims 1 to 4, wherein the engagement element is either a roller or a sprag.