JP2016044797A - Reverse input cutoff clutch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reverse input cutoff clutch which is inhibited from returning to a lock state once again immediately after the lock state is released.SOLUTION: A clutch 70 comprises rollers 80a, 80b which are arranged between an internal peripheral face of an outer ring 77 and an external peripheral face of an output shaft 74, and a spring 81 for energizing the rollers 80a, 80b. An input shaft includes pressing parts 73a, 73b and 73c which press the rollers 80a, 80b. There is formed a lock part 86 in which an interval between the internal peripheral face of the outer ring 77 and the external peripheral face of the output shaft 74 gradually becomes narrow toward one direction along a circumferential direction. Each of the pressing parts 73a, 73b and 73c has a first end part 82a which presses one roller 80a in direction at a side opposite to one direction, and a second end part 82b at a side opposite to the first end part 82a. The spring 81 is arranged between the first end part 82a and the roller 80a.SELECTED DRAWING: Figure 8

Description

  The present invention relates to a reverse input cutoff clutch.

  In the prior art, an internal combustion engine having a variable compression ratio mechanism that changes a compression ratio during an operation period is known. The variable compression ratio mechanism can change the compression ratio by changing the volume of the combustion chamber when the piston reaches top dead center.

  When fuel burns in the combustion chamber of the internal combustion engine and the in-cylinder pressure rises, a force acts on the members constituting the combustion chamber in a direction in which the volume of the combustion chamber increases. This force also acts on the variable compression ratio mechanism and may be transmitted to a rotating machine such as a motor that drives a mechanism that changes the volume of the combustion chamber. For this reason, it is known that the variable compression ratio mechanism is provided with a reverse input cutoff clutch that blocks the rotational force due to the in-cylinder pressure so that the rotational force due to the in-cylinder pressure is not transmitted to the output shaft of the rotating machine. The reverse input cut-off clutch has a lock function that cuts off the rotational force applied to the output shaft.

  Japanese Patent Application Laid-Open No. 2010-014155 discloses a reverse input shut-off clutch in which a roller engages with a wedge gap formed between a stationary side member and an output shaft member. In this reverse input cutoff clutch, it is disclosed that a contact point where the cage and the roller come in contact is located on a straight line connecting the center of the wedge angle of the wedge gap and the center of the roller.

  Japanese Patent Application Laid-Open No. 2012-229964 discloses a lock release device that releases a locked state of a torque diode that prevents load torque of an output shaft from being transmitted to an input shaft when torque is not transmitted from the input shaft to the output shaft. Has been. In this unlock control device, it is disclosed that the unlock torque is gradually increased when the locked state is not released even if the set unlock torque is continuously applied for a predetermined time.

JP 2010-014155 A JP 2012-229774 A

  The reverse input cutoff clutch blocks transmission of rotational force in a predetermined rotational direction from the output shaft to the input shaft, while transmitting rotational force of the input shaft to the output shaft. When the rotational force is transmitted from the input shaft to the output shaft, the reverse input cutoff clutch is unlocked.

  The reverse input cut-off clutch cuts off the reverse input torque input to the output shaft when the roller is locked to the wedge-shaped portion. When a rotational force is input to the input shaft, the roller is pressed by the cage. Then, the locked state can be released by detaching the roller from the wedge-shaped portion. After releasing the locked state, the rotational force is transmitted from the input shaft to the output shaft.

  However, in the conventional reverse input cutoff clutch in the prior art, immediately after the lock state is released, the roller may return to the wedge-shaped portion again and may be locked again. That is, there are cases where the complete release of the locked state of the reverse input cutoff clutch fails.

  An object of this invention is to provide the reverse input interruption | blocking clutch which suppresses returning to a locked state again immediately after canceling | released a locked state.

  The reverse input cutoff clutch of the present invention includes an input shaft to which rotational force is input, an output shaft to which rotational force is transmitted from the input shaft and outputs rotational force, an outer ring that houses the input shaft and the output shaft, An engagement element disposed between the inner peripheral surface of the outer ring and the outer peripheral surface of the output shaft, and a biasing member that biases the engagement element are provided. The input shaft includes a pressing portion that presses the engaging element. The reverse input cutoff clutch is formed with a locking portion in which the distance between the inner peripheral surface of the outer ring and the outer peripheral surface of the output shaft is gradually narrowed in one direction along the circumferential direction. The pressing portion has a first end that presses one engaging element in a direction opposite to the one direction, and a second end opposite to the first end. The urging member is disposed between the first end and one engagement element.

  In the above invention, the second end portion faces the other engaging element, and the biasing member has the other end engaging the other engaging element while the input shaft is stationary. It is preferable to have an urging force that presses in the direction.

  ADVANTAGE OF THE INVENTION According to this invention, the reverse input interruption | blocking clutch which suppresses returning to a locked state again immediately after canceling | released a locked state can be provided.

1 is a schematic overall view of an internal combustion engine in an embodiment. It is a general | schematic exploded perspective view of the variable compression ratio mechanism in embodiment. It is a 1st schematic sectional drawing of the variable compression ratio mechanism explaining the change of the mechanical compression ratio in embodiment. It is a 2nd schematic sectional drawing of the variable compression ratio mechanism explaining the change of the mechanical compression ratio in embodiment. It is a 3rd schematic sectional drawing of the variable compression ratio mechanism explaining the change of the mechanical compression ratio in embodiment. It is the 1st schematic sectional view of the clutch of a locked state in an embodiment. It is a 2nd schematic sectional drawing of the clutch of the locked state in embodiment. It is a schematic sectional drawing of a clutch when the lock state in an embodiment is canceled. It is a schematic sectional drawing of the clutch of the locked state in a comparative example. It is a schematic sectional drawing of a clutch when the locked state in a comparative example is cancelled | released.

  With reference to FIGS. 1 to 10, the reverse input cutoff clutch in the embodiment will be described. In the present embodiment, a reverse input cutoff clutch attached to a variable compression ratio mechanism of an internal combustion engine will be described as an example.

  FIG. 1 is a schematic diagram of an internal combustion engine according to an embodiment. The internal combustion engine includes an engine body 90. The engine body 90 includes a support structure including the crankcase 1. The support structure supports the crankshaft. The engine main body 90 includes a cylinder block 2 and a cylinder head 3. A piston 4 is disposed in a hole formed in the cylinder block 2. An ignition plug 6 is disposed on the top surface of the combustion chamber 5.

  An intake port 8 and an exhaust port 10 are formed in the cylinder head 3. An intake valve 7 is disposed at the end of the intake port 8. An exhaust valve 9 is disposed at the end of the exhaust port 10. The intake port 8 is connected to a surge tank 12 via an intake branch pipe 11. A fuel injection valve 13 for injecting fuel into the corresponding intake port 8 is arranged in each intake branch pipe 11.

  The surge tank 12 is connected to an air cleaner 15 via an intake duct 14. A throttle valve 17 driven by an actuator 16 is disposed inside the intake duct 14. An intake air amount detector 18 is disposed inside the intake duct 14. On the other hand, the exhaust port 10 is connected through an exhaust manifold 19 to, for example, a catalyst device 20 containing a three-way catalyst. An air-fuel ratio sensor 21 is disposed in the exhaust manifold 19.

  The internal combustion engine in the present embodiment includes a variable compression ratio mechanism A that can change the volume of the combustion chamber 5 when the piston 4 is located at the compression top dead center. The variable compression ratio mechanism A is formed so as to change the relative position of the cylinder block 2 with respect to the crankcase 1 in the cylinder axial direction. A lift spring 65 is disposed between the crankcase 1 and the cylinder block 2.

  A relative position sensor 22 for detecting the relative position of the cylinder block 2 with respect to the crankcase 1 is attached to the engine body 90. A throttle opening sensor 24 for generating an output signal indicating the throttle valve opening is attached to the actuator 16 for driving the throttle valve.

  The control device for the internal combustion engine in the present embodiment includes an electronic control unit 30. Electronic control unit 30 in the present embodiment includes a digital computer. The digital computer includes a ROM (Read Only Memory) 32, a RAM (Random Access Memory) 33, a CPU (Microprocessor) 34, an input port 35 and an output port 36 connected to each other by a bidirectional bus 31.

  Output signals of the intake air amount detector 18, the air-fuel ratio sensor 21, the relative position sensor 22, and the throttle opening sensor 24 are input to the input port 35 via the corresponding AD converter 37. A load sensor 41 that generates an output voltage proportional to the amount of depression of the accelerator pedal 40 is connected to the accelerator pedal 40. The output of the load sensor 41 is input to the input port 35 via the corresponding AD converter 37. Further, the input port 35 is connected to a crank angle sensor 42 that generates an output pulse every time the crankshaft rotates, for example, 30 °. From the output of the crank angle sensor 42, the crank angle and the engine speed can be detected.

  On the other hand, the output port 36 is connected to the ignition plug 6, the fuel injection valve 13, the actuator 16 for driving the throttle valve, and the variable compression ratio mechanism A through a corresponding drive circuit 38. These devices are controlled by the electronic control unit 30.

  FIG. 2 is an exploded perspective view of the variable compression ratio mechanism in the present embodiment. FIG. 3 shows a first schematic cross-sectional view of the variable compression ratio mechanism in the present embodiment. Referring to FIGS. 2 and 3, a plurality of protrusions 50 spaced from each other are formed below both side walls of cylinder block 2. A cam insertion hole 51 having a circular cross section is formed in the protrusion 50. On the other hand, the upper wall of the crankcase 1 is formed with a plurality of protrusions 52 that are fitted between the protrusions 50 at intervals. The protrusion 52 is also formed with a cam insertion hole 53 having a circular cross section.

  The variable compression ratio mechanism in the present embodiment includes camshafts 54 and 55. On the camshafts 54 and 55, circular cams 58 that are rotatably inserted into the cam insertion holes 53 are arranged. The circular cam 58 is coaxial with the rotational axis of the cam shafts 54 and 55. On the other hand, on both sides of the circular cam 58, eccentric shafts 57 arranged eccentrically with respect to the rotational axes of the cam shafts 54 and 55 extend as shown in FIG. Another circular cam 56 is eccentrically attached to the eccentric shaft 57 so as to be rotatable. The circular cam 56 is disposed on both sides of the circular cam 58. The circular cam 56 is rotatably inserted into the corresponding cam insertion hole 51. The cylinder block 2 is supported by the crankcase 1 via camshafts 54 and 55 including an eccentric shaft 57.

  FIG. 4 shows a second schematic cross-sectional view of the variable compression ratio mechanism in the present embodiment. FIG. 5 shows a third schematic cross-sectional view of the variable compression ratio mechanism in the present embodiment. When the circular cams 58 arranged on the camshafts 54 and 55 are rotated in opposite directions from the state shown in FIG. 3, the eccentric shafts 57 move in directions toward each other. The eccentric shaft 57 rotates around the rotation axis of the respective camshafts 54 and 55. The cylinder block 2 moves away from the crankcase 1 as indicated by an arrow 99. At this time, the circular cam 56 rotates in the cam insertion hole 51. As shown in FIG. 4, the position of the eccentric shaft 57 changes from a low position to an intermediate height position.

  When the circular cam 58 is further rotated in the direction indicated by the arrow 68, the cylinder block 2 further moves away from the crankcase 1 as indicated by the arrow 99. As a result, the eccentric shaft 57 is at the highest position as shown in FIG. 3 to 5 show the positional relationship among the center a of the circular cam 58, the center b of the eccentric shaft 57, and the center c of the circular cam 56 in each state.

  When the cylinder block 2 is separated from the crankcase 1, the volume of the combustion chamber 5 when the piston 4 is located at the compression top dead center increases. Referring to FIG. 5, the cylinder block 2 approaches the crankcase 1 when the circular cam 58 is rotated in the direction indicated by the arrow 69 from the state in which the volume of the combustion chamber 5 is large as opposed to this control. As a result, the volume of the combustion chamber 5 when the piston 4 is located at the compression top dead center is reduced. Thus, by rotating the camshafts 54 and 55, the volume of the combustion chamber 5 when the piston 4 is located at the compression top dead center can be changed.

  Referring to FIG. 2, the variable compression ratio mechanism of the present embodiment includes a drive device that rotates camshafts 54 and 55 for changing the volume of combustion chamber 5. The drive device includes a motor 59 as a rotating machine. Further, the drive device includes a clutch 70, worms 61 and 62, worm wheels 63 and 64, and the like. The rotary shaft 66 is connected to the output shaft of the motor 59 and the input shaft of the clutch 70. The rotating shaft 60 is connected to the output shaft of the clutch 70.

  A pair of worms 61 and 62 whose spiral directions are opposite to each other are attached to the rotary shaft 60 so that the camshafts 54 and 55 are rotated in opposite directions. Worm wheels 63 and 64 that mesh with the worms 61 and 62 are fixed to end portions of the camshafts 54 and 55.

  In this embodiment, by driving the motor 59, the volume of the combustion chamber 5 when the piston 4 is located at the compression top dead center can be changed over a wide range. The variable compression ratio mechanism is controlled by the electronic control unit 30, and the motor 59 that rotates the camshafts 54 and 55 is connected to the output port 36 via the corresponding drive circuit 38.

  In the variable compression ratio mechanism in the present embodiment, the cylinder block 2 moves relative to the crankcase 1 so that the volume of the combustion chamber 5 when the piston reaches top dead center is variably formed. Yes. In the present embodiment, the compression ratio determined only from the stroke volume of the piston from the bottom dead center to the top dead center and the volume of the combustion chamber when the piston reaches the top dead center is referred to as a mechanical compression ratio. The mechanical compression ratio does not depend on the closing timing of the intake valve, etc., (mechanical compression ratio) = (combustion chamber volume when piston reaches top dead center + piston stroke volume) / (piston up The volume of the combustion chamber when reaching the dead point).

  In the state shown in FIG. 3, the volume of the combustion chamber 5 is small and the mechanical compression ratio is high. When the intake air amount is always constant, the actual compression ratio becomes high. On the other hand, in the state shown in FIG. 5, the volume of the combustion chamber 5 is large and the mechanical compression ratio is low. When the intake air amount is always constant, the actual compression ratio is low.

  With reference to FIG. 1, in the present embodiment, the cylinder block 2 is urged by the lift spring 65 in a direction away from the crankcase 1. During the operation period of the internal combustion engine, a force acts in a direction in which the cylinder block 2 approaches the crankcase 1 due to the influence of gravity or the negative pressure of the combustion chamber 5 in the intake stroke of the combustion cycle. However, by arranging the lift spring 65, the cylinder block 2 is always urged in the direction away from the crankcase 1, and the occurrence of vibration or the like in the cylinder block 2 can be suppressed. Further, whenever fuel is burned in the combustion chamber 5, a force acts in a direction in which the cylinder block 2 is separated from the crankcase 1 due to the in-cylinder pressure.

  Referring to FIG. 2, in the variable compression ratio mechanism according to the present embodiment, clutch 70 is arranged in the driving force transmission path for transmitting the rotational force output from motor 59 to camshafts 54 and 55. In the present embodiment, the torque applied to the input shaft of the clutch 70 by the output of the motor 59 is referred to as the input torque of the clutch 70. The torque applied to the output shaft of the clutch 70 via the camshafts 54 and 55 by the force acting on the cylinder block 2 is referred to as reverse input torque of the clutch 70.

  The clutch 70 of the present embodiment is a reverse input cutoff clutch. The clutch 70 is formed so as to block the rotational force (reverse input torque) applied to the output shaft. In particular, the clutch 70 blocks the rotational force in the direction in which the cylinder block 2 is separated from the crankcase 1. On the other hand, the clutch 70 is formed to transmit a rotational force (input torque) applied to the input shaft to the output shaft.

  FIG. 6 shows a first schematic cross-sectional view of the clutch in the present embodiment. FIG. 7 shows a second schematic cross-sectional view of the clutch in the present embodiment. FIG. 7 is a schematic cross-sectional view taken along line X in FIG. FIG. 6 shows a state where the input shaft is stationary without applying a rotational force to the input shaft.

  Referring to FIGS. 6 and 7, clutch 70 of the present embodiment includes an outer ring 77 that houses input shaft 71 and output shaft 74 therein. The outer ring 77 is fixed to the housing 78 by screws 85. The outer ring 77 is fixed without moving during the period in which the clutch 70 is driven. The clutch 70 has an output shaft 74. The output shaft 74 is connected to the rotating shaft 60 to which the worms 61 and 62 are fixed. The output shaft 74 rotates about the rotation shaft 88 as a rotation center. The output shaft 74 has a hole 75. A plurality of holes 75 are formed along the circumferential direction in which the output shaft 74 rotates. The output shaft 74 has a plurality of bulging portions 74a that gradually bulge outward along the circumferential direction on the outer peripheral surface. The bulging part 74a is formed corresponding to the position where the rollers 80a and 80b are disposed.

  The clutch 70 includes an input shaft 71. The input shaft 71 rotates about the rotation shaft 88 as a rotation center. The input shaft 71 is connected to a rotating shaft 66 that transmits the rotational force of the motor 59. The input shaft 71 has a plurality of insertion portions 72 and a plurality of pressing portions 73a, 73b, 73c. The pressing portions 73a, 73b, and 73c have a function of pressing the roller. The insertion part 72 has a function of pressing and rotating the output shaft. The insertion portion 72 and the pressing portions 73a, 73b, and 73c rotate integrally.

  The plurality of insertion portions 72 are formed at positions corresponding to the plurality of hole portions 75 of the output shaft 74. The insertion portion 72 is inserted into the hole 75 of the output shaft 74. The inner diameter of the hole portion 75 is formed to be larger than the outer diameter of the insertion portion 72. A gap is formed between the insertion portion 72 and the hole 75. The plurality of pressing portions 73a, 73b, 73c are disposed between the outer ring 77 and the output shaft 74. The pressing portions 73a, 73b, and 73c extend along the circumferential direction.

  In the space between the output shaft 74 and the outer ring 77, a plurality of rollers 80a and 80b as engaging elements are arranged. The rollers 80a and 80b in the present embodiment are formed in a cylindrical shape. In the range shown in FIG. 6, the roller 80a is connected to the pressing portion 73a via a spring 81 as an urging member. The roller 80b is connected to the pressing portion 73b via a spring 81. The spring 81 urges the connected pressing portion and the roller in a direction away from each other.

  An arrow 100 is a direction corresponding to the direction in which the cylinder block 2 moves up with respect to the crankcase 1. That is, the rotational direction in which the mechanical compression ratio decreases is shown. As described above, force is always applied to the cylinder block 2 in the direction away from the crankcase 1 by the lift spring 65. The urging force in the direction in which the cylinder block 2 moves away from the crankcase 1 is transmitted to the camshafts 54 and 55 and converted into a rotational force. The rotational force generated in the camshafts 54 and 55 is transmitted to the output shaft 74 of the clutch 70 via the worm wheels 63 and 64 and the worms 61 and 62. For this reason, reverse input torque is applied to the output shaft 74 in the direction indicated by the arrow 100.

  A locking portion 86 for locking the rollers 80a and 80b is formed by the bulging portion 74a formed on the output shaft 74 and the outer ring 77. The locking portion 86 has a wedge shape. The locking portion 86 is a portion where the distance between the inner peripheral surface of the outer ring 77 and the outer peripheral surface of the output shaft 74 is gradually narrowed in one direction along the circumferential direction. In this embodiment, the direction opposite to the direction indicated by the arrow 100 corresponds to the one direction described above. The locking part 86 is formed narrow so that the rollers 80a and 80b do not pass through.

  Of the plurality of pressing portions, the pressing portion 73a includes a first end portion 82a that presses one roller 80a in a direction opposite to one direction (the direction indicated by the arrow 100), a first end portion 82a, And an opposite second end 82b. A recess 82c is formed in the first end portion 82a. The spring 81 is disposed inside the recess 82c. That is, the spring 81 is disposed between the first end portion 82a and the one roller 80a, and urges the first end portion 82a and the one roller 80a in a separating direction. The other pressing portions 73b and 73c have the same configuration as the pressing portion 73a.

  Next, the operation of the clutch 70 in the present embodiment will be described. In a state where the input shaft 71 is stationary without applying a rotational force to the input shaft 71, reverse input torque is applied to the output shaft 74 in the direction indicated by the arrow 100. The roller 80 a is pressed by the second end portion 82 b of the pressing portion 73 c by the urging force of the spring 81 and is locked to the locking portion 86. Similarly, the roller 80b is pressed by the second end portion 82b of the pressing portion 73a and is locked to the locking portion 86. For this reason, the effect of the wedge acts on the rollers 80a and 80b, and the rotation of the output shaft 74 with respect to the outer ring 77 is prevented. The output shaft 74 is locked. In this manner, the clutch 70 can block the rotational force from the output shaft side corresponding to the direction in which the cylinder block 2 is separated from the crankcase 1.

  FIG. 8 is a schematic cross-sectional view of the clutch for explaining the operation when the mechanical compression ratio is lowered. When lowering the mechanical compression ratio, the cylinder block 2 is moved away from the crankcase 1. By driving the motor 59, the input shaft 71 rotates in the direction indicated by the arrow 101. The spring 81 contracts, and the pressing portions 73a, 73b, 73c and the insertion portion 72 rotate in the direction indicated by the arrow 101. Before the insertion portion 72 contacts the inner surface of the hole 75, the first end portion 82a contacts the rollers 80a and 80b. The rollers 80a and 80b are separated from the locking portion 86, and the wedge effect acting on the rollers 80a and 80b disappears. For this reason, the locked state of the output shaft 74 is released, and the output shaft 74 can rotate with respect to the outer ring 77 in the direction indicated by the arrow 100. When the insertion portion 72 of the input shaft 71 presses the hole 75 of the output shaft 74, the output shaft 74 can be rotated. Thus, the rotational force of the input shaft 71 can be transmitted to the output shaft 74.

  Referring to FIG. 6, when the mechanical compression ratio is increased, by driving motor 59, input shaft 71 is rotated in the direction opposite to the direction indicated by arrow 100. The insertion portion 72 and the pressing portions 73a, 73b, and 73c rotate in the direction opposite to the direction indicated by the arrow 100. The bulging portion 74 a of the output shaft 74 rotates in a direction opposite to the direction indicated by the arrow 100. A force acts on the rollers 80a and 80b in a direction away from the locking portion 86. For this reason, the wedge effect acting on the rollers 80a and 80b is released. When the insertion portion 72 of the input shaft 71 presses the hole 75 of the output shaft 74, the rotational force of the input shaft 71 can be transmitted to the output shaft 74.

  FIG. 9 is a schematic cross-sectional view showing a state where the clutch of the comparative example is stationary without applying input torque to the input shaft. The clutch of the comparative example is different from the clutch of the present embodiment in the arrangement of the spring 81. The spring 81 is connected to the second end portion 82 b on the opposite side to the direction indicated by the arrow 100 among the end portions on both sides of the pressing portion 83 of the input shaft. Then, the first end portion 82a presses the roller 80a.

  FIG. 10 is a schematic cross-sectional view for explaining the operation when the mechanical compression ratio is lowered in the clutch of the comparative example. The input shaft is rotated in the direction indicated by arrow 101. The pressing portion 83 presses the rollers 80a and 80b to release the clutch locked state. Then, when the input shaft insertion portion 72 presses the hole 75 of the output shaft 74, the output shaft 74 rotates.

  In the clutch of the comparative example, each roller 80a, 80b is urged by the spring 81 in the direction opposite to the rotation direction of the input shaft indicated by the arrow 101 even after the locked state is released. For this reason, the clutch may return to the locked state immediately after releasing the locked state of the clutch. In other words, since the rollers 80a and 80b are urged toward the locking portion 86, the rollers 80a and 80b may mesh with the locking portion 86 again, and the lock state may fail to be released.

  Referring to FIG. 8, on the other hand, in the clutch 70 of the present embodiment, when the clutch is unlocked, the rollers 80 a and 80 b are urged by the spring 81 in the direction away from the locking portion 86. Yes. For this reason, it can suppress effectively returning to a locked state again immediately after canceling the locked state of the clutch 70. FIG.

  Furthermore, referring to FIG. 6, in the clutch 70 of the present embodiment, when the clutch 70 is locked, the first end portion 82a of the pressing portion 73a and the roller 80a are not in contact with each other, and a gap is formed. ing. In order to reduce the mechanical compression ratio, the pressing portion 73a is moved first and then brought into contact with the roller 80a. That is, it collides with the roller 80a in a state where the speed of the pressing portion 73a is increased. Referring to FIG. 9, in the clutch of the comparative example, the pressing portion 83 is in contact with the rollers 80a and 80b, and the speed when the pressing of the rollers 80a and 80b is started is zero. For this reason, the clutch of this Embodiment can make the input torque for canceling | released a locked state smaller than the clutch of a comparative example. For example, the capacity of the motor 59 (see FIG. 2) of the driving device can be made smaller than that of the motor driving the clutch of the comparative example.

  Referring to FIG. 6, in clutch 70 of the present embodiment, roller 80b is disposed as another engaging element facing second end portion 82b. The spring 81 is a biasing force that causes the second end portion 82b to press the roller 80b in the direction opposite to the direction indicated by the arrow 100 in a state where the input shaft 71 is stationary while no input torque is applied to the input shaft 71. Have That is, in a state where no rotational force is applied to the input shaft 71, the roller 80b is pressed by the pressing portion 73a. Similarly, the roller 80a is pressed by the pressing portion 73c. Since the rollers 80a and 80b are pressed toward the locking portion 86, the locked state in which the rollers 80a and 80b are locked to the locking portion 86 can be reliably maintained.

  The clutch in the present embodiment transmits the rotational force from the input shaft in both the rotational direction in which the mechanical compression ratio increases and the rotational direction in which the mechanical compression ratio decreases to the output side, and in the rotational direction in which the mechanical compression ratio decreases. Although it is formed so as to block the rotational force from the output shaft, it is not limited to this form, and it may be formed so as to block the rotational force in both directions from the output shaft.

  The reverse input cut-off clutch in the present embodiment is attached to the variable compression ratio mechanism of the internal combustion engine, but is not limited to this form, and any reverse input that cuts off transmission of reverse input torque that rotates in at least one direction. The present invention can be applied to a cutoff clutch.

  In the respective drawings described above, the same or equivalent parts are denoted by the same reference numerals. In each of the above-described controls, the order of the steps can be appropriately changed within a range where the function and the action are not changed. In addition, said embodiment is an illustration and does not limit invention. Further, in the embodiment, changes in the form shown in the claims are included.

70 Clutch 71 Input shaft 73a, 73b, 73c Pressing portion 74 Output shaft 74a Swelling portion 77 Outer ring 80a, 80b Roller 81 Spring 82a, 82b End portion 86 Locking portion 88 Rotating shaft

Claims (2)

An input shaft to which rotational force is input;
An output shaft that receives the rotational force from the input shaft and outputs the rotational force;
An outer ring that houses the input shaft and the output shaft;
An engagement element disposed between the inner peripheral surface of the outer ring and the outer peripheral surface of the output shaft;
An urging member for urging the engagement element,
The input shaft includes a pressing portion that presses the engaging element,
A locking portion is formed in which the distance between the inner peripheral surface of the outer ring and the outer peripheral surface of the output shaft gradually decreases in one direction along the circumferential direction.
The pressing portion has a first end that presses one engaging element in a direction opposite to the one direction, and a second end opposite to the first end,
An urging member is disposed between the first end and the one engagement element, and is a reverse input cutoff clutch. The second end portion faces another engaging element,
2. The reverse input cut-off clutch according to claim 1, wherein the biasing member has a biasing force with which the second end presses the other engagement element in the one direction when the input shaft is stationary. 3. .

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