JP2011202766A - Self lock clutch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To rationally constitute a self lock clutch which provides a high lock torque when a rotation force acts on a driven side.SOLUTION: The self lock clutch includes a worm gear 10 rotating around a first axis X1, and a wheel gear 20 rotating around a second axis X2. The worm gear 10 is supported to be freely displaced in a direction along the first axis X1, and a lock member 31 is provided displaced from a neutral position to a lock position when the wheel gear 20 is rotated by the action of the external force and the worm gear 10 is displaced to a direction along the first axis X1, and a lock plate 35 is provided which has a fitting recession 36 fitted with the lock member 31 on the lock position and obstructs the rotation of the worm gear 10.

Description

  The present invention relates to a gear transmission system including a drive-side worm gear on one of the shaft cores having a staggered relationship and a driven wheel gear engaged with the worm gear on the other of the shaft cores. The present invention relates to a self-locking clutch that prevents rotation of a wheel gear when an external force is applied to the wheel gear in a case where the worm gear is large and the self-locking function of the worm gear itself is difficult to expect.

  As related to the self-locking clutch configured as described above, Patent Document 1 discloses a driving-side rotating body that is rotated by a driving force of a motor, and a follower to which the rotating force of the driving-side rotating body is transmitted by contact. The side rotator is arranged on a coaxial core, and is provided with a clutch housing that has a cylindrical shape with an axial center and a coaxial core at a position surrounding them, and a roller-like support member to which the rotational force of the driving side rotator is transmitted by contact The structure provided with rolling elements is shown.

  In Patent Document 1, the distance between the central portion of the control surface formed integrally with the driven-side rotating body and the inner surface of the clutch housing is set to be slightly larger than the diameter of the rolling element, and in a region away from the central portion in the circumferential direction, The distance from the inner surface of the clutch housing is shorter than the diameter of the rolling element. A rolling element is disposed between the control surface and the inner surface of the clutch housing, and the clutch housing is supported so as not to rotate.

  When the motor is driven to rotate from such a structure, the driven-side rotating body and the support member rotate integrally, and the rolling element rotates at the position of the central portion of the control surface by the rotation of the support member. When a rotational force is applied to the driven side rotating body from the outside while the motor is stopped, the rolling body is sandwiched between the control surface and the inner surface of the clutch housing as the driven side rotating body rotates. A state is reached and this rotation is prevented.

Japanese Patent No. 3887172

  As described in Patent Document 1, when an external force is applied to the driven side rotating body, the roller-shaped rolling element is locked between the control surface of the driven body and the inner surface of the cylindrical clutch housing. In the structure having the structure of the above, even if the amount of rotation is small, the locked state is reached and the reverse rotation can be suppressed.

  However, the configuration described in Patent Document 1 not only requires high accuracy, but also generates torque (lock torque) that prevents rotation by contact between the outer surface of the rolling element and the inner surface of the clutch housing. Therefore, when the contact area is small and a high load is applied, there is a risk of causing slippage. Further, in order to obtain a high lock torque, the size is increased and there is room for improvement.

  It is also considered to use a worm gear having a large advance angle in order to increase the transmission efficiency of a reduction system that transmits the rotation of the worm gear driven by the actuator to the wheel gear.

  An object of the present invention is to rationally configure a self-locking clutch that realizes self-locking that provides a reliable and high locking torque even when a worm gear having high gear efficiency is used.

A feature of the present invention is that it includes a drive-side worm gear that rotates about the first axis of the first axis and the second axis that have a discrepancy relationship, and the driven side that rotates about the second axis. The wheel gear is provided at a position to mesh with the worm gear,
The worm gear and a shaft portion integrally formed with the worm gear are supported so as to be displaceable in a direction along the first shaft core, and a cylindrical body fitted around the shaft portion cannot be displaced in the direction of the first shaft core. When the external force acts on the wheel gear in the rotational direction by being supported rotatably about the first axis, the cylindrical shape is accompanied by the displacement of the worm in the direction along the first axis. It has a displacement structure that allows displacement of the shaft portion inside the body,
In a state where the driving force is transmitted from the worm gear to the wheel gear, the lock member provided on one of the cylindrical body and the shaft portion is held at a neutral position in the direction of the first axis, and the wheel gear A guide mechanism for moving the lock member to a lock position displaced in a direction along the first axis with respect to the neutral position.
A plurality of members that do not contact the lock member at the neutral position and engage with the lock member at the lock position to prevent rotation of the shaft portion outside the other of the cylindrical body and the shaft portion. The rotation preventing body having the engaging recess is arranged.

According to this configuration, when the driving force of the worm gear is transmitted to the wheel gear, the guide mechanism holds the lock member in the neutral position, so that the lock member is not brought into contact with the engagement recess of the rotation preventing body. Further, for example, when the wheel gear is rotated by the action of an external force in a state where the rotation of the worm gear is stopped, the worm gear and the shaft portion are integrated along the first axis as the wheel gear rotates. The guide mechanism allows this displacement. For this reason, the lock member moves from the neutral position to the lock position and engages with the engagement concave portion of the rotation preventing body, thereby preventing the rotation of the worm gear. Since the prevention of the rotation is realized by the engagement between the lock member and the engagement recess, an extremely large lock torque is obtained, and high accuracy is not required as compared with Patent Document 1. This means that a reliable lock can be realized even if a configuration in which the worm gear with a large advance angle is used to increase the transmission efficiency is used, and even if a configuration having a small-capacity electric motor in the drive source is used. Thus, it is possible to prevent an unnecessary external force from acting on the electric motor.
Therefore, a self-locking clutch that realizes self-locking that provides a reliable and high locking torque even when a worm gear having high gear efficiency is used has a structure that does not require high accuracy.

  According to the present invention, the rotation blocking body is disposed at two positions sandwiching the neutral position, and the guide mechanism is an opening that forms a parallelogram having a diagonal line along the circumferential direction of the cylindrical body. The locking member that is formed in the cylindrical body and penetrates the opening and becomes the neutral position on the diagonal line may be formed in the shaft portion.

  According to this, when an external force that rotates the wheel gear acts in the direction opposite to the direction in which the wheel gear rotates due to the drive rotation of the worm gear, or when an external force that rotates the wheel gear acts in the opposite direction, The worm gear and the shaft portion are displaced in a direction along the first axis, and the lock member moves along the opening edge of the opening along with the displacement, so that the lock member is displaced to the lock position and is engaged with the engaging recess of the rotation preventing body. This will prevent the wheel gear from rotating.

According to the present invention, the guide mechanism is formed on the outer periphery of the shaft portion as a concave portion having a parallelogram shape having a diagonal line along the circumferential direction of the cylindrical body, and is engaged with the concave portion on the diagonal line. A guide body that is a neutral position is configured to be fixed to the cylindrical body,
The shaft or the member integrally formed with the shaft is provided with the lock member so as to protrude outward from the first shaft core, and the rotation prevention is performed at two positions sandwiching the lock member in a neutral position. A body may be placed.

  According to this, when an external force that rotates the wheel gear acts in the direction opposite to the direction in which the wheel gear rotates due to the drive rotation of the worm gear, or when an external force that rotates the wheel gear acts in the opposite direction, The worm gear and the shaft portion are displaced in the direction along the first axis in a form in which the guide member moves along the opening edge of the opening. Along with this displacement, the lock member also reaches the lock position along the first axis and engages with the engagement recess of the rotation preventer, thereby preventing the wheel gear from rotating.

  In the present invention, the rotation preventing body may be formed in a disk shape, and the recesses may be formed radially around the first axis and formed on the outer peripheral side of the rotation preventing body.

  According to this, when an external force that rotates the wheel gear is applied, the rotation of the wheel gear can be prevented without causing the worm gear to rotate unnecessarily, regardless of the rotation position of the worm gear. The amount of rotation of the wheel gear until it is made can be made very small.

  In the present invention, the engagement recess may include an engagement surface along a cross-sectional shape of the lock member.

  According to this, in a state where the lock member and the engagement recess are engaged, the engagement recess can be brought into intimate contact with the outer periphery of the lock member, which eliminates the problem of excessively concentrated local force and is stable. A special lock appears.

It is a general view which shows the structure of a self-locking clutch. It is a general view showing a self-locking clutch in a locked state. It is the side view and perspective view which show a state with a locking member in the neutral position of a guide opening. It is the side view and perspective view which show the state which has a locking member in the locking position of a guide opening by the effect | action of the external force to a reverse direction. It is a side view which shows the state which has a lock member in the lock position of a guide opening by the effect | action of the external force to a forward direction. It is a figure which shows the shape of a guide opening. It is sectional drawing which shows a locking member and an engagement recessed part. It is a general view which shows the structure of the self-locking clutch of another embodiment. It is sectional drawing of the site | part of the guide opening of another embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the self-locking clutch of the present invention includes a worm gear 10 that is rotatably supported around a first axis X1, and a wheel gear 20 that is rotatably supported around a second axis X2. It has a gear reduction system consisting of Furthermore, a displacement structure is provided that supports the worm gear 10 so as to be displaceable in the direction along the first axis X1, and when the wheel gear 20 is rotated by the action of an external force, the worm gear 10 is displaced in the direction along the first axis X1. At the same time, the lock mechanism 30 functions to prevent the rotation of the worm gear 10 by reaching the locked state. The self-locking clutch configured as described above is provided, for example, in a transmission system that operates up and down the door glass of a vehicle, and details thereof will be described below.

[Gear reduction system]
The first shaft core X1 and the second shaft core X2 are arranged in a staggered relationship in a direction orthogonal to each other, and a drive-side worm gear 10 that rotates about the first shaft core X1 is provided. Further, a driven wheel gear 20 that rotates about the second axis X2 is provided, and the worm gear 10 and the wheel gear 20 are disposed at positions where they mesh with each other. Thus, the gear reduction system is configured.

(Displacement structure)
A control shaft portion 11 (an example of a shaft portion) having a circular cross-sectional shape is integrally formed at one end portion of the worm gear 10, and a support shaft portion 12 having a circular cross-sectional shape is integrally formed at the other end portion. . The support shaft portion 12 is supported by a bearing 13 formed of a radial ball bearing so as to be rotatable and displaceable in a direction along the first axis X1 with respect to the inner race of the bearing 13. Note that the worm gear 10 and the control shaft portion 11 may be manufactured separately and connected to each other in a screw manner, or may be integrally formed by bonding or welding.

  A cylindrical body 15 is provided that is rotatable coaxially with the first axis X1 and that cannot be displaced in a direction along the first axis X1. The control shaft 11 is rotatable relative to the cylindrical body 15 with respect to the hole 15A formed on the same axis as the first axis X1, and is displaceable in the direction along the first axis X1. The inner fitting is supported.

  Both ends of the cylindrical body 15 are rotatably supported by bearings 16 formed of radial ball bearings, and the pair of bearings 16 are prevented from moving in the direction along the first axis X1. The pair of bearings 16 are supported by a fixed system such as a frame of a self-locking clutch.

  With this configuration, when a force is applied to displace the worm gear 10 in the direction along the first axis X1, the control shaft portion 11 is maintained in the state of being fitted in the hole 15A of the cylindrical body 15 while maintaining the state of being fitted inside the hole 15A. The shaft 12 moves in the direction along the single axis X1 and the support shaft 12 moves relative to the bearing 13 in the direction along the first axis X1. Thereby, the worm gear 10, the control shaft part 11, and the support shaft part 12 are displaced integrally.

[Lock mechanism]
As shown in FIG. 7, a pin-shaped lock member 31 penetrating in the diametrical direction with respect to the control shaft portion 11 is fitted and fixed so that both end portions protrude from the outer surface of the control shaft portion 11. A pair of guide openings 32 (an example of a guide mechanism) through which the lock member 31 penetrates are formed in the cylindrical body 15. In the state where the rotational driving force of the electric motor 17 is transmitted from the worm gear 10 to the wheel gear 20, the guide opening 32 causes the lock member 31 to be neutral in the direction of the first axis X1, as shown in FIGS. Hold at position N. Note that the neutral position N and the pair of lock positions L exist on a virtual plane in a posture orthogonal to the first axis X1.

  When the wheel gear 20 is rotated by the action of an external force, the lock member 31 is formed into a shape that can be moved to the lock position L in accordance with the displacement of the control shaft portion 11 as shown in FIGS. Has been.

  As shown in FIGS. 3 to 6, the guide opening 32 intersects the two main vertices 32 </ b> N at the position intersecting the virtual plane where the neutral position N is present and the two virtual planes where the lock position L is present. It has a shape that is a parallelogram having two sub-vertices 32L. The present invention does not exclude the case where the guide opening 32 is formed in a diamond shape. In the case where the guide opening 32 is formed in a diamond shape, one of the two diagonal lines is formed so as to coincide with the neutral position N.

  The angle between the short side of the four guide sides of the guide opening 32 and the reference line X1 ′ parallel to the first axis X1 is set to θ1, the long side of the four guide sides, and the first axis X1. The angle with respect to the reference line X1 ′ parallel to is set to θ2. The angle θ1 is set to be smaller than the angle θ2.

  A pair of disk-shaped lock plates 35 (an example of a rotation blocking body) are provided in a position perpendicular to the first axis X1 at a position sandwiching the neutral position N outside the cylindrical body 15. Each lock plate 35 has an opening 35 </ b> A in which the cylindrical body 15 is arranged at the center, and the lock member 31 can be engaged with a surface (opposite surface) facing the pin-shaped lock member 31. A large number of engaging recesses 36 are formed.

  As shown in FIGS. 3, 4, and 7, many engaging recesses 36 are formed radially about the first axis X <b> 1, and the cross-sectional shape of the recesses is a part of the cross-sectional shape of the lock member 31. By aligning (matching) with each other, in a state in which the lock member 31 is engaged with the engagement recess 36, they are brought into contact with each other over a wide surface so that they can be stably engaged and held. The pair of lock plates 35 are held in relative positional relation by spacers 37. In this manner, the lock member 30, the guide opening 32, and the lock plate 35 constitute the lock mechanism 30.

  The self-locking clutch of the present invention may be configured without the spacer 37 by supporting the pair of lock plates 35 on a fixing system such as a frame of the self-locking clutch.

(Lock operation)
In this self-locking clutch, the driving force from the electric motor 17 is directly transmitted to the worm gear 10 with respect to the cylindrical body 15 to drive and rotate, and the wheel gear 20 meshing with the worm gear 10 is driven to rotate. The generated rotational force can be taken out from the output shaft 21 that rotates integrally with the wheel gear 20.

  Further, at the time of this driving rotation, the worm gear 10 is driven to rotate by transmitting a rotational force from the cylindrical body 15 to the control shaft portion 11 via the lock member 31. Further, since the rotational force is transmitted by the lock member 31 coming into contact with the opening edge of the guide opening 32, the lock member 31 is stabilized at the position of the main vertex 32N, and the lock member 31 is in the neutral position N. The lock member 31 is held and does not come into contact with the engagement recess 36 of the lock plate 35.

  For example, when the wheel gear 20 is rotated by the action of an external force while the rotation of the electric motor 17 is stopped, the worm gear 10 is rotated along with the rotation of the wheel gear 20 regardless of the rotation direction. As a result of the displacement along the first axis X1, the lock member 31 moves along the inner peripheral surface of the guide opening 32 and reaches the lock position L.

In particular, this self-locking clutch is in a state in which the control shaft portion 11 is rotated in the direction shown in FIG. 1 by the driving force from the electric motor 17 in a situation in which a load is applied to the wheel gear 20 (for example, the door glass is lifted) In the state to be applied), reverse torque (load) always acts on the wheel gear 20. In such a case, a thrust force acts in a direction in which the control shaft portion 11 is pulled out, and in the worm gear 10 having a large advance angle, a reverse rotational torque corresponding to the advance angle acts on the control shaft portion 11.
At this time, the thrust force due to the reverse torque acts as a force for the lock member 31 to slide on the short side and move in the direction of the lock position L (leftward in FIG. 1), but the reverse rotation torque acting simultaneously is on the short side. Thus, it acts as a force for moving the lock member 31 in the direction of the neutral position N (downward in FIG. 1).

  As a result, in a situation where reverse torque acts, both the reverse rotation torque due to reverse input and the rotation torque due to motor driving work as unlocking forces, so that the lock member 31 is stably held at the neutral position N.

Then, when the rotation of the electric motor 17 is loosened, and the reverse torque (load) acting on the wheel gear 20 with respect to the driving force of the electric motor 17 has been won, the lock member can be obtained only by the unlocking force by the motor driving torque. Since the force is insufficient as a force for holding 31 at the neutral position N, the lock member 31 moves to the left along the short side of the guide opening 32 and reaches the lock position L as shown in FIGS. The lock member 31 is engaged with the engagement recess 36 of the lock plate 35 to reach a certain locked state.
Here, if the angle θ1 (see FIG. 6) of the short side is reduced, it is easy to move in the left lock direction, and if θ1 is increased, it is difficult to move in the left lock direction and it is easy to move to the neutral position N. Become.

  On the contrary, when the forward torque acts on the wheel gear 20 in an increased manner, it acts as follows. This is the case, for example, when an external force in the downward direction is further applied to the door glass while the door glass is being lowered. In FIG. 1, the electric motor 17 is rotating in the direction opposite to the white arrow. The lock member 31 is in the neutral position N above the guide opening 32. When further external force is applied from this state, a thrust force acts on the control shaft portion 11 in the pulling direction. When the advance angle of the worm gear 10 is large, a forward rotation torque corresponding to the advance angle is applied to the control shaft portion 11. As a result, the lock member 31 slides on the long side of the guide opening 32 and moves to the lock position L on the left side in FIG. The lock member 31 is engaged with the engagement recess 36 of the lock plate 35, and the rotation of the control shaft portion 11 is temporarily stopped. As described above, even when the electric motor 17 is driven to lower the door glass, when the pressing external force is applied, the rotation of the control shaft portion 11 is stopped and the electric motor 17 is damaged. It can be effectively prevented.

  The guide opening 32 formed in the cylindrical body 15 is formed asymmetrically left and right. This is due to the following reason. For example, it is assumed that the electric motor 17 that is normally rotating in the state of FIG. 1 stops. At this time, clockwise torque acts on the wheel gear 20, and the wheel gear 20 tries to pull out the control shaft portion 11 to the left side in FIG. 1 as the rotation of the control shaft portion 11 stops. Therefore, the lock member 31 first tries to move leftward. At the same time, the worm gear 10 is forced to rotate in the direction opposite to the direction of the white arrow in FIG. Since this force and the force in the pulling-out direction act on the control shaft portion 11, the lock member 31 tends to move with a resultant force F1 directed downward to the left as shown in FIG. As a result, the lock member 31 slides on the short side of the guide opening 32 and reaches the right auxiliary vertex 32L.

  On the other hand, it is assumed that an external force for further accelerating the rotation of the wheel gear 20 is applied during the steady rotation of the electric motor 17 in the state of FIG. At this time, counterclockwise torque acts on the wheel gear 20, and the control shaft portion 11 is pushed to the right side in FIG. Therefore, the lock member 31 first tries to move rightward. At the same time, the rotation of the worm gear 10 is accelerated by the wheel gear 20 in the direction of the white arrow in FIG. Since the accelerated force and the force in the pushing direction act on the control shaft portion 11, the lock member 31 tends to move with a resultant force F2 facing the upper right as shown in FIG. As a result, the lock member 31 slides on the long side of the guide opening 32 and reaches the right auxiliary vertex 32L.

  In the present device, when the electric motor 17 is stopped or accelerated from a state of steady rotation, if the torque fluctuation is substantially the same, the lock member 31 has the same movement characteristics on both the left and right sides. It is configured. That is, the angle θ1 of the short side and the angle θ2 of the long side of the guide opening 32 are set as shown in FIG. 6, the angle α1 formed by the resultant force F1 and the short side, and the angle α2 formed by the combined force F2 and the long side Are set approximately equal to each other. As a result, even when a force is applied to the lock member 31 in either the left or right direction, the resistance force when the lock member 31 slides on the short side is approximately equal to the resistance force when the lock member 31 slides on the long side. It is set to.

[Removal from lock position]
With the above configuration, the left and right characteristics are substantially the same when the lock member 31 is disengaged from the left and right lock positions L and moved to the neutral position N. For example, as shown in FIG. 4, when the control shaft portion 11 is locked in a state of being pulled out, the downward leftward force F <b> 1 continues to act as described above. From this state, if the control shaft portion 11 is rotated again to a larger load, the rotation direction is a direction in which the control shaft portion 11 is moved upward, and the lock member 31 returns to the neutral position N along the short side. There is a need. Therefore, the force for releasing the lock member 31 from the lock position is determined based on the angle θ1 formed by the resultant force F1 and the short side.

On the other hand, as shown in FIG. 5, when acceleration is temporarily applied to the rotating control shaft portion 11 and the control shaft portion 11 is locked to the right side in a state of being pulled out, as described above. An upper right force F2 is applied. However, when the action of the temporary external force is weakened from this state and the driving force of the electric motor 17 is won again, the lock member 31 slides on the long side of the guide opening 32 and is at the lower neutral position N. Start moving to. At this time, the force for releasing the lock member 31 from the lock position is determined based on the angle θ2 formed by the resultant force F2 and the long side.

  Incidentally, assuming that the guide opening 32 has a diamond shape, the long side and the short side are not distinguished, and the influence of the rotational torque due to the advance angle of the worm gear 10 is not taken into consideration. In such a case, it is easy to lock the wheel gear 20 on the side on which the forward torque acts with respect to the motor rotation direction, and it is difficult to release the lock even if the forward torque becomes weak. The side where the reverse torque acts on the motor rotation direction is difficult to lock, and when the reverse torque becomes weak, the lock is easily released. When the torque acting on the wheel gear 20 fluctuates, there is a difference in how the lock is entered depending on the direction of the torque.

  For such a phenomenon, by setting the short side angle θ1 smaller than the long side angle θ2 with respect to the reference line X1 ′ as described above, the reverse torque and the forward torque are equal in torque (the absolute values are equal). The torque is locked.

  Thus, in the self-locking clutch of the present invention, even when the electric motor 17 is stopped or the electric motor 17 is in operation, when the wheel gear 20 is rotated by an external action, The worm gear 10 is displaced by the rotational force in the direction along the first axis X1, and the lock member 31 is engaged with the engagement recess 36 of the lock plate 35 so that a reliable lock can be revealed.

  In addition, since the lock member 31 is formed so as to protrude outward with the first axis X1 as the center, the lock member 31 is engaged with any one of the plurality of engagement recesses 36 to enter the locked state. When it is reached, a very high lock torque is obtained.

  In particular, by setting the shape of the guide opening 32 to a parallelogram and adjusting the component force in the sliding direction acting on the lock member 31 between when a reverse torque acts and when a forward torque acts, When the motor 17 is operating, the absolute value of the reverse torque when the reverse torque acts to reach the locked state and the absolute value of the forward torque when the forward torque acts to reach the locked state are made equal. The balance of the lock operation is improved.

[Another embodiment]
In this other embodiment, common numbers and symbols are assigned to those having the same functions as those of the above-described embodiments. That is, as shown in FIGS. 8 and 9, the guide opening 32 is formed in a concave shape in the control shaft portion 11, and the guide body 15 </ b> G engaged with the concave guide opening 32 is fixed to the cylindrical body 15 to guide the guide mechanism. Configure. Further, a lock member 31 protrudes from the support shaft portion 12 at the end opposite to the control shaft portion 11, and a pair of lock plates 35 having engagement recesses 36 into which the lock member 31 is engaged are connected to the lock member 31. It arrange | positions in the position which pinches | interposes 31.

  The guide openings 32 are formed as parallelograms having diagonal lines in a posture along the circumferential direction of the cylindrical body 15 (coincident with the circumferential direction of the control shaft portion 11), and the positions of the diagonal lines correspond to the neutral position N. Although not shown in detail in the drawing, the guide opening 32 having a parallelogram has a long side and a short side as in the above-described embodiment, and has angles θ1 and θ2 with respect to the reference line. Is set. Similar to the embodiment described above, the control shaft 11 is supported rotatably about the first axis X1, the cylindrical body 15 is rotatable coaxially with the first axis X1, and the first axis. It is supported so that it cannot be displaced in the direction along X1.

  With such a configuration, when the rotational driving force of the electric motor 17 is transmitted from the worm gear 10 to the wheel gear 20, the neutral position N formed in the guide opening 32 moves to a position where it is held in contact with the guide body 15G. The lock member 31 is also held in the neutral position. When the wheel gear 20 is rotated by the action of an external force, the guide opening 32 is displaced while being in sliding contact with the guide body 15G to reach the lock position. Accordingly, the lock member 31 moves to the lock position L along with the displacement of the control shaft portion 11, and the lock member 31 is engaged with the engagement recess 36 of the lock plate 35 to reach the locked state.

  Accordingly, when the wheel gear 20 is rotated by an external action, even when the electric motor 17 is stopped or the electric motor 17 is driven as in the embodiment described above, The worm gear 10 is displaced in the direction along the first axis X1 by the rotational force, and the lock member 31 is engaged with the engagement recess 36 of the lock plate 35 so that a reliable lock can be revealed. In particular, according to the present invention, when the wheel gear 20 is rotated by the action of an external force, a reliable locked state appears. Therefore, a reduction system using a worm gear having a large advance angle is configured to increase transmission efficiency. It is also possible to use a small capacity electric motor as a drive source.

  Further, in this alternative embodiment, a configuration in which the lock member 31 and the lock plate 35 are disposed at an intermediate position between the worm gear 10 and the control shaft portion 11 may be employed.

  The present invention can be applied to all transmission systems that require high locking torque without relying on the self-locking function of the deceleration system itself in the deceleration system that transmits the rotational force of the worm gear to the wheel gear.

10 Worm gear 11 Shaft (control shaft)
15 cylindrical body 15G guide body 20 wheel gear 31 lock member 32 guide mechanism (guide opening)
35 Anti-rotation body (lock plate)
36 Engaging recess L Lock position N Neutral position X1 First axis X2 Second axis

Claims (5)

A drive side worm gear that rotates about the first axis of the first axis and the second axis that have a discrepancy relationship is provided, and the driven wheel gear that rotates about the second axis is the worm gear. And prepare for the position to bite
The worm gear and a shaft portion integrally formed with the worm gear are supported so as to be displaceable in a direction along the first shaft core, and a cylindrical body fitted around the shaft portion cannot be displaced in the direction of the first shaft core. When the external force acts on the wheel gear in the rotational direction by being supported rotatably about the first axis, the cylindrical shape is accompanied by the displacement of the worm in the direction along the first axis. It has a displacement structure that allows displacement of the shaft portion inside the body,
In a state where the driving force is transmitted from the worm gear to the wheel gear, the lock member provided on one of the cylindrical body and the shaft portion is held at a neutral position in the direction of the first axis, and the wheel gear A guide mechanism for moving the lock member to a lock position displaced in a direction along the first axis with respect to the neutral position.
A plurality of members that do not contact the lock member at the neutral position and engage with the lock member at the lock position to prevent rotation of the shaft portion outside the other of the cylindrical body and the shaft portion. A self-locking clutch in which a rotation preventing body having an engaging recess is arranged.   The cylindrical rotation body is formed as an opening that is a parallelogram having a diagonal line in a posture along the circumferential direction of the cylindrical body, and the rotation prevention body is disposed at two positions sandwiching the neutral position. 2. The self-locking clutch according to claim 1, wherein the locking member that is formed in the opening and that penetrates the opening and becomes the neutral position on the diagonal line is formed in the shaft portion. The guide mechanism is formed on the outer periphery of the shaft portion as a concave portion that is a parallelogram having a diagonal line along the circumferential direction of the cylindrical body, and is engaged with the concave portion to be a neutral position on the diagonal line. The guide body is configured to be fixed to the cylindrical body,
The shaft or the member integrally formed with the shaft is provided with the lock member so as to protrude outward from the first shaft core, and the rotation prevention is performed at two positions sandwiching the lock member in a neutral position. The self-locking clutch according to claim 1, wherein the body is disposed.   The self-rotation body according to claim 3, wherein the rotation prevention body is formed in a disc shape, and a plurality of the recesses are formed radially around the first axis and formed on the outer peripheral side of the rotation prevention body. Lock clutch.   The self-locking clutch according to claim 4, wherein the engaging recess includes an engaging surface that follows a cross-sectional shape of the locking member.

Images