JP2017215021A - Reverse input prevention clutch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lock-type reverse input prevention clutch which is suppressed in heat generation caused by slide movement between a lock engagement piece and a fixed member at the transmission of rotation to an output side from an input side, and can secure a torque capacity.SOLUTION: A ball 9 which is small in slide resistance with respect to an outer ring 5 is used as a lock engagement piece arranged between an inner ring 3 being a part of an output-side member 4 and the outer ring 5 being a part of a fixed member 12, a contact load acting between the ball 9 in a locked state and the outer ring 5 and the inner ring 3 is dispersed by assembling the balls 9 in a state of being aligned in a plurality of pieces in an axial direction, heat generation at the transmission of rotation to an output side from an input side is suppressed by suppressing the contact surface pressure of each ball 9 more than the case that a roller is used as the lock engagement piece, and a torque capacity which is not largely smaller than that in the case of using the roller can be secured.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a reverse input prevention clutch that transmits rotation of an input side member to an output side member when input torque is applied, and prevents the input side member from rotating with respect to reverse input torque.

  The reverse input prevention clutch transmits its rotation to the output side member when input torque is applied to the input side member, and prevents the input side member from rotating when reverse input torque is applied to the output side member. It is to make. There is a type of the reverse input prevention clutch that locks the output side member against reverse input torque (hereinafter, this method is referred to as “lock type”) (see, for example, Patent Document 1).

  The lock-type reverse input prevention clutch described in Patent Document 1 is configured such that the input side member rotates with a slight angle delay between the input side member and the output side member that rotate about the same axis. Torque transmission means for transmitting to the member is provided, a fixing member is arranged on the radially outer side of the output side member, a plurality of cam surfaces are provided on the outer peripheral surface of the output side member, and the inner peripheral cylindrical surface of the fixing member and the output side member A wedge-shaped space that gradually narrows in the circumferential direction is formed between the cam surfaces of each of the cam surfaces, and a pair of rollers that serve as lock engaging members and springs that push the rollers into the narrow portion of the wedge-shaped space are incorporated in each wedge-shaped space. In each wedge-shaped space, on both sides in the circumferential direction (positions facing the spring in the circumferential direction across the roller), pillar portions of the cage that rotate integrally with the input side member are inserted.

  In this reverse input prevention clutch, each roller is pushed into the narrow portion of the wedge-shaped space by the elasticity of the spring. Therefore, even if reverse input torque is applied to the output side member, the roller on the rear side in the rotation direction is the inner side of the fixed member. By engaging the circumferential cylindrical surface and the cam surface of the output side member, the output side member is locked with the fixed member, and rotation is not transmitted to the input side member.

  On the other hand, when input torque is applied to the input side member, the pillar portion of the cage that rotates integrally with the input side member pushes the roller on the rear side in the rotation direction against the elasticity of the spring to the wide portion of the wedge-shaped space. Thus, after the engagement between the roller and the fixing member and the output side member is released and the output side member is released from the locked state, rotation is transmitted from the input side member to the output side member by the torque transmitting means. (At this time, the roller on the front side in the rotational direction moves relative to the wide portion of the wedge-shaped space, so that it does not engage with the fixed member and the output side member).

Japanese Patent No. 4965871

  By the way, in the lock type reverse input prevention clutch using the roller as the lock engagement member as described above, the roller is in line contact with the inner peripheral cylindrical surface of the fixed member when the rotation is transmitted from the input side member to the output side member. Since sliding occurs, the inside of the clutch becomes hot due to heat generated by the sliding, and there is a risk of premature deterioration of the lubricant enclosed in the clutch. In particular, in applications where the input side member is directly connected to the motor, the motor rotation is input without going through the speed reduction mechanism. Deterioration tends to be a problem. As a countermeasure against this problem, it is considered effective to reduce the sliding resistance of the lock engagement element with respect to the fixing member by replacing the lock engagement element from a roller to a ball.

  However, when a ball is used as the lock engagement element, the ball is in point contact with the inner peripheral cylindrical surface of the fixing member and the cam surface of the output side member. The contact surface pressure generated between the output side member and the output side member increases, thereby reducing the torque capacity.

  SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a lock-type reverse input prevention clutch that generates less heat due to sliding between a lock engagement element and a fixing member during rotation transmission from the input side to the output side and can secure a torque capacity. And

  In order to solve the above problems, a reverse input preventing clutch according to the present invention includes an input side member and an output side member arranged in a state of rotating around the same axis, and a radially outer side of the output side member. A locking member that locks the output side member and the fixing member with respect to the reverse input torque applied to the output side member, and the locking means with respect to the input torque applied to the input side member. Unlocking means for releasing the locked state, and torque transmitting means for transmitting the input torque applied to the input side member to the output side member when the locked state is released, wherein the locking means includes: A curved surface is provided on the inner periphery of the fixing member, and a plurality of cam surfaces are provided on the outer periphery of the output side member, and a circumferential direction is provided between the inner peripheral curved surface of the fixing member and each cam surface of the output side member. so Secondly, narrow wedge-shaped spaces are formed, and a plurality of balls as lock engagement elements are axially arranged in each wedge-shaped space, and each of the balls is pushed into the narrow portion of the wedge-shaped space by a spring. It was supposed to be.

  That is, by using a ball having a small sliding resistance with respect to the fixed member as a lock engagement element, heat generation at the time of rotation transmission from the input side to the output side can be suppressed as compared with the case of using the roller, and the ball is When multiple rollers are arranged in the axial direction, the contact load acting between the ball in the locked state and the fixed member and the output side member is dispersed, and the contact surface pressure of each ball is suppressed. The torque capacity that is not inferior to the above can be secured.

  Here, the wedge-shaped spaces are formed in a plurality of consecutive circumferentially in the same narrowing direction, and the balls are arranged one by one in the circumferential direction in each wedge-shaped space, of which in the circumferential direction By adopting a configuration in which a plurality of balls arranged in a continuous wedge-shaped space are pressed against the springs in contact with adjacent ones in the circumferential direction, the torque capacity can be increased by increasing the total number of balls incorporated. Can be further increased.

  In addition, when the spring is a coil spring that presses the balls arranged on both sides in the circumferential direction at both ends, the both ends are formed so as to cover a part of the balls, It is desirable to make it difficult for the coil spring to move radially outward even when it receives a centrifugal force during transmission of rotation from the input side to the output side. In this way, it is possible to prevent problems such as wear and breakage due to contact / sliding with the fixed member of the coil spring, and the coil spring does not have a posture in which the ball cannot be sufficiently pushed into the narrow portion of the wedge-shaped space. Also, it is possible to prevent a lock failure with respect to the reverse input torque.

  Furthermore, in the above case, the coil spring may be formed in a drum shape in which the diameter of the central portion in the expansion / contraction direction is smaller than the diameters of both end portions. In this way, contact between the central portion of the coil spring and the outer peripheral surface of the output side member can be avoided, so that the coil spring can be smoothly expanded and contracted when the locked state is released or when returning from the unlocked state to the locked state. The stable clutch operation can be obtained.

  As described above, the reverse input preventing clutch according to the present invention uses a ball having a sliding resistance smaller than that of the roller as a lock engaging member, and incorporates a plurality of such balls aligned in the axial direction to secure a torque capacity. However, since heat generation during rotation transmission from the input side to the output side can be suppressed, early deterioration of the lubricant enclosed in the clutch can be prevented even in applications that operate at high speed. Can be used stably for a long time.

Longitudinal front view of the reverse input prevention clutch of the first embodiment Sectional view along the line II-II in FIG. Sectional view along line III-III in FIG. Side view of the spring of FIG. a and b are sectional views for explaining the clutch operation corresponding to FIG. Sectional drawing of the principal part which shows the modification of a spring corresponding to FIG. Sectional drawing along the VII-VII line of FIG. Sectional drawing corresponding to FIG. 2 of the principal part of the reverse input prevention clutch of 2nd Embodiment Sectional view along line IX-IX in Fig. 8 (excluding outer ring)

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 to 5 show a first embodiment. As shown in FIGS. 1 and 2, the reverse input prevention clutch includes an input shaft 1 as an input side member, an output side member 4 in which an output shaft 2 and an inner ring 3 are integrally formed, and a radially outer side of the inner ring 3. A two-stage cylindrical housing 6 integrally formed with the outer ring 5, a presser lid 7 attached to one end of the housing 6, and a plurality of column portions 8 a inserted between the inner ring 3 and the outer ring 5. The retainer 8, the steel ball (lock engagement element) 9 and the coil spring 10 incorporated between the inner ring 3 and the outer ring 5 and the inner periphery of the small diameter portion at the other end of the housing 6 are rotated to rotate the output shaft 2. It is comprised with the sintered bearing 11 supported freely.

  The housing 6 is formed with a plurality of notches 6a on the outer peripheral edge of the flange at one end, and a claw 7a formed on the outer peripheral edge of the presser lid 7 is fitted into these notches 6a and bent. It is integrated with the lid 7. The presser lid 7 is provided with attachment holes 7b in three tongue-shaped projecting portions projecting from the outer periphery thereof. The housing 6 and the presser lid 7 serve as a fixing member 12 that is integrally fixed to an external member (not shown) through an attachment hole 7 b of the presser lid 7.

  The input shaft 1 includes an engaging portion 1a having a two-sided width (two engaging surfaces parallel to the shaft center and parallel to each other) on the outer periphery, and a small-diameter cylindrical portion 1b protruding from an end surface of the engaging portion 1a. The distal end portion of the engaging portion 1a is inserted into an engaging hole 3a provided in the center of the inner ring 3, and the small diameter cylindrical portion 1b is output from the bottom of the engaging hole 3a of the inner ring 3 to the output shaft. 2 is fitted in the circular hole 2a and rotates around the same axis as the output side member 4 (the output shaft 2 and the inner ring 3). Here, the engagement hole 3a of the inner ring 3 has a cross section substantially the same shape as the engagement portion 1a of the input shaft 1, and a slight rotational clearance is generated when the engagement portion 1a of the input shaft 1 is inserted. Thus, torque transmitting means is configured to transmit the input torque applied to the input shaft 1 to the output side member 4 with a slight angular delay.

  In addition, the cylindrical portion 8b of the cage 8 is fitted into the axially central portion of the engaging portion 1a of the input shaft 1 so that the input shaft 1 and the cage 8 rotate integrally. An input torque is applied to the input shaft 1 from a drive source (not shown) such as a motor, and the output shaft 2 is a rotation transmission member (such as an output gear) attached to an engaging portion 2b having a two-sided width formed on the outer periphery. Torque is output in the illustration (not shown).

  The inner circumference of the outer ring 5 is a cylindrical surface, and a plurality of cam surfaces 3 b are provided in the circumferential direction on the outer circumference of the inner ring 3, and between the inner circumferential cylindrical surface of the outer ring 5 and each cam surface 3 b of the inner ring 3. A wedge-shaped space 13 that is gradually narrowed on both sides in the circumferential direction is formed. As shown in FIG. 3, a pair of the balls 9 is incorporated in each wedge-shaped space 13 in the circumferential direction in a state where three balls 9 are arranged in the axial direction, and the coil spring 10 is sandwiched between the pairs of balls 9. Each ball 9 is pushed into a narrow part of the wedge-shaped space 13. As a result, a locking means is configured to lock the inner ring 3 that is a part of the output side member 4 and the outer ring 5 that is a part of the fixing member 12 against the reverse input torque applied to the output side member 4. . The inner circumference of the outer ring is not limited to the cylindrical surface as in this embodiment, and a curved surface that forms a wedge-shaped space may be provided between the inner ring and the cam surface of the inner ring.

  Here, as shown in FIG. 4, the coil spring 10 is formed in a drum shape in which the diameter of the central portion in the expansion / contraction direction is smaller than the diameters of both end portions that press the ball 9. As shown in FIGS. 2 and 3, both end portions cover a part of the balls 9 arranged on both sides in the circumferential direction, and the central portion is incorporated without contacting the cam surface 3 b of the inner ring 3. .

  In addition, as shown in FIG. 2, column portions 8 a of the cage 8 are inserted on both sides in the circumferential direction of each wedge-shaped space 13 (positions facing the coil spring 10 in the circumferential direction with the ball 9 in between). Yes. Thereby, when input torque is applied to the input shaft 1, the cage 8 rotates integrally with the input shaft 1, and the column portion 8 a of the cage 8 is pushed in the counter-rotating direction by the coil spring 10. The ball 9 is pushed out to the vast part of the wedge-shaped space 13 to release the locked state by the locking means. That is, the cage 8 serves as a lock release means for releasing the locked state with respect to the input torque applied to the input shaft 1.

  This reverse input prevention clutch is configured as described above, and each ball 9 is pushed into the narrow portion of the wedge-shaped space 13 by the elasticity of the coil spring 10, so that even if reverse input torque is applied to the output side member 4, The ball 9 pressed in the counter-rotating direction by the coil spring 10 engages with the outer ring 5 that is a part of the fixing member 12 and the inner ring 3 that is a part of the output side member 4, whereby the output side member 4 is fixed. 12 and is not transmitted to the input shaft 1.

  On the other hand, when input torque is applied to the input shaft 1, first, as shown in FIG. 5A, the column portion 8 a of the cage 8 that rotates together with the input shaft 1 is rotated in the counter-rotating direction by the coil spring 10. By pushing the pressed ball 9 against the elasticity of the coil spring 10 to the wide part of the wedge-shaped space 13, the engagement between the ball 9, the outer ring 5 and the inner ring 3 is released, and the output side member 4 is Release from the locked state. Then, as shown in FIG. 5 (b), when the input shaft 1 further rotates and the engagement portion 1 a engages with the engagement hole 3 a of the inner ring 3, the rotation of the input shaft 1 passes through the inner ring 3. (At this time, the ball 9 pushed in the rotational direction by the coil spring 10 moves relative to the wide part of the wedge-shaped space 13, and thus engages with the outer ring 5 and the inner ring 3. Never).

  Here, the ball 9 slides with the outer ring 5 while rolling when the rotation is transmitted from the input shaft 1 to the output side member 4 as described above, but the outer ring is compared with a roller used as a conventional lock engagement element. The sliding resistance with respect to 5 is small. In addition, since a plurality of balls 9 are assembled in the axial direction, the contact load acting between the balls 9 in the locked state and the outer ring 5 and the inner ring 3 is dispersed, and the contact surface pressure of each ball 9 is reduced. It can be suppressed. Therefore, heat generation during rotation transmission from the input side to the output side can be suppressed as compared with the case where rollers are used as the lock engaging elements, and a torque capacity not greatly inferior when using rollers can be secured.

  In addition, the coil spring 10 is formed so that both ends thereof cover a part of the ball 9, and it is difficult for the coil spring 10 to move outward in the radial direction even if it receives a centrifugal force during rotation transmission from the input side to the output side. For this reason, there is no possibility of causing problems such as wear and breakage due to contact / sliding with the outer ring 5, and the ball 9 is not sufficiently pushed into the narrow part of the wedge-shaped space 13, and the lock against reverse input torque is obtained. There is no possibility of causing defects.

  Furthermore, since the coil spring 10 is formed in a drum shape, the center portion does not contact the cam surface 3 b of the inner ring 3. As a result, when the locked state is released or when returning from the unlocked state to the locked state, the coil spring 10 expands and contracts smoothly, and a stable clutch operation can be obtained.

  6 and 7, instead of the drum-shaped coil spring 10 described above, a coil spring 14 having a substantially rectangular outer shape viewed from the axial direction and capable of pressing the three balls 9 arranged in the axial direction alone is used. An example is shown. And although illustration is abbreviate | omitted, as for this coil spring 14, both ends each covers a part of three balls 9, and the short direction dimension of the center part of an expansion-contraction direction is smaller than the short direction dimension of both ends. The center portion is formed so as not to contact the cam surface 3b of the inner ring 3.

  8 and 9 show a second embodiment. In this embodiment, two cam surfaces 3b having the same inclination direction are provided on the outer periphery of the inner ring 3 continuously in the circumferential direction, so that the wedge-shaped space 15 having the same narrowing direction is formed between the outer ring 5 and the inner ring 3 in the circumferential direction. Are formed in succession, and three balls 9 are arranged in each wedge-shaped space 15 in an axially aligned state. Then, three drum-shaped coil springs 10 incorporated in a space where the vast portions of the wedge-shaped space 15 face each other are brought into contact with each other by two balls 9 arranged in the circumferential direction at each of both end portions. It is pushed into 15 narrow parts. Further, the column portion 8a of the cage 8 serving as the unlocking means is inserted into a position where the narrow portions of each wedge-shaped space 15 face each other, that is, a space at a position facing the coil spring 10 in the circumferential direction with the ball 9 interposed therebetween. Yes. Other configurations and clutch operations (the locking of the output side member with respect to the reverse input torque and the releasing operation of the locked state) are the same as those in the first embodiment. In this embodiment, the coil spring 14 shown in FIGS. 6 and 7 can be used instead of the three drum-shaped coil springs 10 arranged in the axial direction.

  In the second embodiment, the total number of balls 9 incorporated is larger than in the first embodiment, and the contact surface pressure of each ball 9 is reduced, so that the torque capacity can be increased.

1 Input shaft (input side member)
DESCRIPTION OF SYMBOLS 1a Engagement part 2 Output shaft 3 Inner ring 3a Engagement hole 3b Cam surface 4 Output side member 5 Outer ring 6 Housing 7 Presser lid 8 Cage 8a Pillar part 9 Ball (lock engagement element)
DESCRIPTION OF SYMBOLS 10 Coil spring 11 Sintered bearing 12 Fixing member 13 Wedge-shaped space 14 Coil spring 15 Wedge-shaped space

Claims (4)

An input side member and an output side member arranged in a state of rotating around the same axis, a fixed member arranged on a radially outer side of the output side member, and a reverse input torque applied to the output side member The lock means for locking the output side member and the fixing member with respect to the above, the lock release means for releasing the lock state by the lock means for the input torque applied to the input side member, and the lock state released Torque transmitting means for transmitting an input torque applied to the input side member to the output side member when in a state;
The locking means is provided with a curved surface on the inner periphery of the fixing member, and a plurality of cam surfaces are provided on the outer periphery of the output side member, and the inner peripheral curved surface of the fixing member and each cam surface of the output side member A wedge-shaped space that is gradually narrowed in the circumferential direction is formed therebetween, and a plurality of balls as lock engaging elements are incorporated in the respective wedge-shaped spaces in the axial direction. Reverse input prevention clutch that is pushed into the part.   A plurality of the wedge-shaped spaces having the same narrowing direction are continuously formed in the circumferential direction, and the balls are arranged one by one in each wedge-shaped space in the circumferential direction, and the wedge-shaped space is continuous in the circumferential direction. The reverse input prevention clutch according to claim 1, wherein a plurality of balls arranged in the space are pressed by the spring in a state of abutting each other with adjacent ones in the circumferential direction.   The said spring is a coil spring which presses the said ball | bowl distribute | arranged to the circumferential direction both sides by both ends, The both ends are formed so that a part of said ball may be covered. The reverse input preventing clutch according to 1 or 2.   The reverse input preventing clutch according to claim 3, wherein the coil spring is formed in a drum shape in which a diameter of a central portion in an expansion / contraction direction is smaller than a diameter of both end portions.

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