JP5990988B2 - Self-locking mechanism for actuator - Google Patents

Description

  The present invention relates to an actuator using a screw member that is rotationally driven by an electric motor or the like. Specifically, for example, it is used for a mechanism part that reciprocates a target part by rotation of a screw member such as an automobile power window, an electric seat, an electric column, an electric parking brake, and the like. Switching is performed stably and reliably.

In an actuator that drives and rotates the screw member, it is important to smoothly move the target part, while in the non-driven state, the target part is required to be surely stationary.
Conventionally, as this type of actuator, for example, there is a device as shown in Patent Document 1.

The actuator includes a cylindrical rotary drive member supported by a housing and driven by a motor;
The rotation driven member is engaged with the rotation driven member in a coaxial core state, and the rotation driven member whose rotation is transmitted in either the left or right direction is screwed to the rotation driven member by the screw portion, and the rotation driven member is rotated. And a long driven part that undergoes thrust movement. That is, by switching the drive rotation direction of the motor, the rotation direction of the rotation driven member is switched, and the elongated driven member that is screwed to the rotation driven member reciprocates.

  On the other hand, in this apparatus, a plurality of roller-shaped rollers are provided between the housing and the rotary driven member so that the driven member is stably stopped when the motor is stopped. The position of this roller is adjusted so that it does not get caught between the housing and the rotary driven member when the rotary driving member rotates. However, when an external force in the thrust direction acts on the driven part when the rotary drive member is not driven and is in a free rotation state, the rotary driven member rotates by a predetermined angle, and as a result, the housing, the rotary driven member, The roller is caught between the rotation driven member and the driven member and the driven member are prevented from moving.

  This actuator is used, for example, in a parking brake of an automobile. According to the description in the specification, the power transmission from the driven member to the motor can be prevented while allowing the power transmission to the driven member by this configuration, so that the motor capacity can be reduced and the power can be saved. It is described that there is.

JP2004-84918

  However, since the self-locking mechanism is configured using the roller brake in the actuator, the contact between the housing and the roller and the contact between the rotary driven member and the roller are linear contacts. For this reason, the load per unit area acting on the contact portion is increased, and the lock function may not be sufficiently exerted depending on the magnitude of the load acting from the outside, or the housing and the rotationally driven member may be damaged in some cases. Inconvenience such as may occur. In order to prevent this, it is necessary to reinforce the parts, for example, by enlarging the dimensions of the member or using a high-strength material. As a result, the size of the device is increased and the cost is increased, resulting in a reasonable device.

  The present invention is for solving these disadvantages, and its main object is to obtain a highly reliable self-locking mechanism capable of stably performing a driving operation and a stopping operation.

[First characteristic configuration]
A first characteristic configuration of the actuator self-locking mechanism according to the present invention includes a screw member that is rotationally driven, a first nut member and a second nut member that are screwed to the screw member, the first nut member, A biasing member that rotates the two nut members relative to each other; and a nut holder that rotatably holds the first nut member and the second nut member. The nut holder is rotationally biased by the biasing member. In addition, it has a first receiving part for restricting the axial movement of the first nut member and a second receiving part for restricting the axial movement of the second nut member that is rotationally biased by the biasing member. is there.

[Function and effect]
As in this configuration, the first nut member and the second nut member are rotationally biased in opposite directions by the biasing member, so that the two nut members are separated from or close to the screw member. Accordingly, the first nut member and the second nut member are configured to abut on a first receiving portion or a second receiving portion provided in the nut holder. When the rotation amount of the first nut member and the second nut member increases in the biasing rotation direction, a contact load is generated between the first nut member and the second nut member and the nut holder.
That is, both nut members are initially rotated in opposite directions according to the pitch of the screw member by the rotation bias of the biasing member. However, when both nut members come into contact with the receiving portion of the nut holder and contact load begins to occur, the rotation of the nut members is limited so that the screw member moves in the direction along the axis of the screw member. Begins to be restricted. Both nut members rotate in the same direction for a while after that, and stop when the contact load increases and relative rotation with respect to the nut holder becomes impossible.

  During this predetermined amount of rotation, the movement of both nut members along the axial direction of the screw member is restricted, while the rotation of the nut member is continued for a while, so the screw between the nut member and the screw member is The frictional force at the joint site increases. When the urging force of the urging member and these frictional forces are balanced, the rotation of both nut members stops. Thereby, each of the nut holder, the first nut member, the second nut member, and the screw member is in an integrated state. As a result, even if an external force is applied to the nut holder or the like when the screw member is in a non-driven state, the screw member is effectively prevented from rotating. Therefore, all members can maintain a stable posture, and a highly reliable self-locking mechanism can be obtained.

  On the other hand, when the screw member is driven again, one of the first nut member and the second nut member receives a rotational force in a direction in which the frictional force is weakened by the rotation of the screw member. As a result, the rotational phase difference between the first nut member and the second nut member is reduced, and the frictional force generated between the two nut members and the screw member is reduced. Therefore, the screw member can be smoothly shifted from the non-driving stationary state to the driving state.

[Second characteristic configuration]
The second characteristic configuration of the actuator self-locking mechanism according to the present invention is that the nut holder is configured such that at least one of the first receiving portion and the second receiving portion can be adjusted in position.

[Function and effect]
As in this configuration, by configuring at least one of the first receiving portion and the second receiving portion so that the position thereof can be adjusted, the interval between the receiving portions to which the first nut member and the second nut member should abut. Changes. Thereby, the relative rotational phase difference of both nut members when a 1st nut member and a 2nd nut member will be in a stationary state can be adjusted.

This is convenient for adjusting the magnitude of the biasing force generated between the first nut member and the second nut member. That is, the biasing force generated by the biasing member can be increased or decreased by adjusting the rotational phase angle or distance between the nut members. This is convenient, for example, when the self-locking mechanism is first assembled.
Further, when the contact portion of the nut member and the receiving portion of the nut holder are worn with use, the relative phase angle between the first nut member and the second nut member changes. In this case, it is necessary to set the urging force again.
By configuring the first receiving portion and the second receiving portion in such a manner that the position can be adjusted, the urging force acting on the first nut member and the second nut member can be appropriately set, and the self-locking mechanism is assembled. Can be made easier and the maintainability thereafter can be improved.

[Third characteristic configuration]
According to a third characteristic configuration of the self-locking mechanism for an actuator according to the present invention, the nut holder includes a first restricting portion that restricts a rotation angle of the first nut member with respect to the nut holder to a predetermined angle; And a second restricting portion for restricting a rotation angle of the nut member with respect to the nut holder to a predetermined angle.

[Function and effect]
Since the first restricting portion and the second restricting portion have substantially the same mechanism, only the first restricting portion will be described here. As in this configuration, when the first nut member is rotationally biased by the biasing member and abuts against the first receiving portion while increasing the contact load, the contact load is set to a predetermined value for re-driving the screw member. Need to stay in range. For example, when the first nut member comes into contact with the first receiving portion, a sudden external force acts on the screw member at the same time, and the first nut member may be over-rotated to the side where the contact load is increased. In this case, the first nut member generates an excessive frictional force on the screw member, which may hinder smooth re-drive of the screw member.

  For this reason, as in this configuration, a restricting portion is provided between the two so that the first nut member does not rotate excessively with respect to the nut holder. Thereby, in the stationary state in which the screw member is not driven, the first nut member and the second nut member are maintained stationary with respect to the screw member by an appropriate frictional force. On the other hand, when the screw member is driven again, the frictional force has a magnitude that does not become an obstacle, so that the actuator can be driven again smoothly.

[Fourth feature configuration]
A fourth characteristic configuration of the actuator self-locking mechanism according to the present invention is such that the first nut member and the second nut member are separated from each other along the axial direction of the screw member by the biasing member. It is biased, and the first receiving portion and the second receiving portion are separately provided on the mutually opposing inner wall surfaces of the nut holder.

[Function and effect]
As in this configuration, the first nut member and the second nut member are arranged inside the nut holder, and the inner wall is also used as a receiving portion, whereby a self-locking mechanism with a reduced number of parts can be obtained.
Further, the distance between the first nut member and the second nut member can be set to the longest by making the most of the size of the nut holder. Therefore, for example, particularly when the screw member is not driven, the posture of the nut holder with respect to the screw member is stabilized, and occurrence of unnecessary rattling is prevented.
Furthermore, since both nut members can be housed in the nut holder, the self-locking mechanism can be protected from external factors and the reliability can be improved.

[Fifth feature configuration]
In the actuator self-locking mechanism according to the present invention, the first nut member and the second nut member are urged by the urging member in a direction close to each other along the axial direction of the screw member, One receiving part and the second receiving part may be separately provided on the wall of the nut holder.

[Function and effect]
With this configuration, for example, it is possible to provide only one wall portion of the nut holder for bringing the first nut member and the second nut member into contact between the first nut member and the second nut member. Become. Therefore, the configuration of the self-locking mechanism can be further simplified.

Side sectional view showing the structure of the actuator self-locking mechanism according to the present embodiment. The disassembled perspective view which shows the principal part of the self-locking mechanism for actuators concerning this embodiment The perspective view which shows the operation | movement outline | summary of a 1st nut member and a 2nd nut member Side sectional view showing structure of self-locking mechanism for actuator according to another embodiment

(Overview)
The actuator self-locking mechanism according to the present invention can be used, for example, in a target portion that reciprocates a power window, an electric seat, and an electric column driving unit of an automobile. Hereinafter, embodiments according to the present invention will be described with reference to FIGS. 1 to 3.

  The self-locking mechanism L includes a screw member 2 that is rotationally driven by the motor 1 or the like, and a first nut member N1 and a second nut member N2 that are screwed into the screw member 2. The first nut member N1 and the second nut member N2 are biased by the biasing member 3 so as to relatively rotate in opposite directions. The first nut member N1 and the second nut member N2 are housed in a box-shaped nut holder 4, for example. The 1st nut member N1 and the 2nd nut member N2 are comprised so that it may contact | abut to the 1st receiving part U1 and the 2nd receiving part U2 which were provided in the inside of the nut holder 4, respectively. As a result, when the screw member 2 is not driven, the nut holder 4 can be held without any play relative to the screw member 2, and the posture of the mechanism portion including the actuator can be stabilized.

As shown in FIGS. 1 and 2, in the self-locking mechanism L of the present embodiment, the screw member 2 passes through the nut holder 4 having a rectangular parallelepiped shape, and the first nut member N <b> 1 and the second nut member are inserted into the screw member 2. N2 is screwed together.
Both ends of the screw member 2 are pivotally supported by two bearing portions 5. A drive motor 1 is connected to one end side of the screw member 2.
The first nut member N1 and the second nut member N2 are twisted and biased in opposite directions by the biasing member 3. In the present embodiment, a coil spring 3a engaged with the first nut member N1 and the second nut member N2 is used as the urging member 3. By this coil spring 3a, the first nut member N1 and the second nut member N2 are urged away from each other, and are pressed against the inner wall surface of the nut holder 4 in a stationary state.

As shown in FIG. 1, the nut holder 4 is provided with a moving table 6 as a moving object. For example, a power window drive unit or a power seat unit can be attached to the movable table 6. In addition to such a relatively large mechanism, various moving parts that are desired to be reciprocated can be connected. Such a moving table 6 may guide reciprocal movement with a dedicated guide rail 7. In other words, the movable table 6 that receives a large load is guided by the strong guide rail 7, and the actuator of this embodiment is intended to reciprocate the movable table 6 and stabilize the stationary state. As a result, it is difficult for a large load to act on the self-locking mechanism L itself, and the self-locking mechanism L can be configured compactly.
Of course, when the screw member 2 and the self-locking mechanism L have sufficient strength and rigidity with respect to the load, it is necessary to make the guide rail 7 of the movable table 6 stronger than necessary. There is no.

(First nut member and second nut member)
As shown in FIG. 2, the first nut member N <b> 1 and the second nut member N <b> 2 include a female screw portion at the center so as to be screwed into the screw member 2. The pitch of the screw member 2 varies depending on the moving object to which the present apparatus is applied. However, according to the self-locking mechanism L, even when an external force is applied to the moving base 6 along the direction of the axis X, the braking effect can be appropriately achieved. Is demonstrated. Therefore, the screw pitch can be set relatively large accordingly.

  For example, as shown in FIG. 2, the first nut member N1 and the second nut member N2 have a shape in which a semi-cylindrical portion and a rectangular parallelepiped portion are combined with the axis X as a boundary. Boss portions B1 and B2 are formed on the side where both nut members are opposed so as to facilitate positioning when the coil spring 3a is attached. Further, on the opposite side, that is, on the outer side of each nut member, a cylindrical first contact portion T1 and second contact portion T2 pressed against the inner wall surface of the nut holder 4 are formed to project. The protruding lengths of the first contact portion T1 and the second contact portion T2 are for reliably pressing the first receiving portion U1 and the second receiving portion U2 provided on the inner wall surface of the nut holder 4. A slight protruding amount may be used.

  In the present embodiment, the contact between the first contact portion T1 and the first receiving portion U1 and the contact between the second contact portion T2 and the second receiving portion U2, in other words, the first contact portion. The braking effect is exhibited by the generation of contact loads between T1 and the first receiving part U1 and between the second contact part T2 and the second receiving part U2, and the first contact part T1 and Friction is not necessarily required between the first receiving part U1 and between the second contact part T2 and the second receiving part U2. A thrust bearing or the like may be interposed between the first contact portion T1 and the first receiving portion U1 and between the second contact portion T2 and the second receiving portion U2 in order to reduce frictional resistance. .

  In addition, the rectangular parallelepiped portion of each nut member is such that the upper end surface of each nut member shown in FIG. This portion of both nut members constitutes a restricting portion which will be described later.

  The first nut member N1, the second nut member N2, the nut holder 4, the screw member 2, and the like can be made of various materials such as metal and resin. The selection of the material is appropriately set according to the external force acting on the screw member 2 or the like at the site where the self-locking mechanism L is adopted or the required durability.

(Biasing member)
As shown in FIG. 2, in this embodiment, the coil spring 3a is locked to the mutually opposing inner surfaces of the first nut member N1 and the second nut member N2. The coil spring 3a twists and biases the first nut member N1 and the second nut member N2 in the direction of the arrow shown in FIG. Since the screw member 2 is generally a right-hand screw, in the case of FIG. 2, the first nut member N1 on the front side is screwed forward while rotating counterclockwise. The second nut member N2 on one back side is screwed to the back side while rotating clockwise. Accordingly, the first contact portion T1 of the first nut member N1 is pressed against the first receiving portion U1 of the nut holder 4, and the second contact portion T2 of the second nut member N2 is It is pressed against the receiving part U2.

  The first nut member N1 and the second nut member N2 are initially separated from each other while rotating in opposite directions according to the pitch of the screw member 2 due to the rotation bias of the biasing member 3. However, when both nut members come into contact with the receiving portion of the nut holder 4 and start to generate contact load, the rotation of both nut members is limited. Accordingly, the movement of the nut members in the direction along the axis X of the screw member 2 starts to be restricted. Both nut members continue to rotate for some time thereafter, the torsional urging force of the coil spring 3a, the contact load between the nut members and the nut holder 4, and between the nut members N1, N2 and the screw member 2 Stops when the frictional force is in an equilibrium state.

  During this predetermined amount of rotation, the more the first nut member N1 and the second nut member N2 move along the direction of the axis X of the screw member 2, the more the reaction from the first receiving portion U1 and the second receiving portion U2 occurs. Power increases. That is, since the first nut member N1 and the second nut member N2 rotate while receiving resistance to the movement of the screw member 2 in the direction of the axis X, the frictional force on the screw member 2 gradually increases. In a state where the rotation of both nut members is stopped, a frictional force is generated between the first nut member N1 and the second nut member N2 and the screw member 2, and at the same time, between the both nut members and the nut holder 4 Contact weighting has occurred. That is, the nut holder 4, the first nut member N1, the second nut member N2, and the screw member 2 are integrated. For this reason, even when the screw member 2 is in a non-driven state and external force acts on the nut holder 4 or the like and the screw member 2 tries to rotate, the frictional force between the nut members N1 and N2 and the screw member 2 Can prevent this and maintain a stable stationary state.

  On the other hand, when the screw member 2 is driven again, one of the first nut member N1 and the second nut member N2 rotates in a direction in which the frictional force is weakened by the rotation of the screw member 2. As a result, the rotational phase difference between the first nut member N1 and the second nut member N2 is reduced, and the contact load between the nut members N1, N2 and the nut holder 4 is reduced. The frictional force generated between the member 2 is reduced. Therefore, the screw member 2 can be smoothly shifted from the non-driving stationary state to the driving state.

  Like this embodiment, the 1st nut member N1 and the 2nd nut member N2 are urged | biased in the mutually separated direction, and the 1st receiving part U1 and the 2nd receiving part U2 are made to the mutually opposing inner wall surface of the nut holder 4 With the configuration provided separately, the receiving portion can be configured by using part of the nut holder 4, and the configuration can be simplified by reducing the number of parts of the self-locking mechanism L. . Moreover, since the nut holder 4 itself is box-shaped and excellent in rigidity, a self-locking mechanism L excellent in strength and rigidity can be obtained.

In this embodiment, since it is the structure which presses the 1st nut member N1 and the 2nd nut member N2 to the inner wall surface which the nut holder 4 opposes, the distance of both nut members can be ensured longest. For this reason, even when an external force acts on the nut holder 4, the posture of the nut holder 4 with respect to the screw member 2 is stabilized. This point contributes to the stabilization of the posture of the nut holder 4 particularly when the screw member 2 is not driven.
Furthermore, according to this configuration, both nut members can be housed in the nut holder 4, so that the self-locking mechanism L can be protected from external factors and reliability can be improved.

(Attaching the first nut member and the second nut member)
In order to attach the coil spring 3 a to the first nut member N <b> 1 and the second nut member N <b> 2, it is necessary to appropriately set a twisting force in order to effectively exhibit the frictional force. As a procedure, first, the first nut member N1 and the second nut member N2 are screwed into the screw member 2 while the coil spring 3a is sandwiched therebetween, and the distance between the two is set to be just within the nut holder 4. In order to allow the coil spring 3a to exert a predetermined twisting force at this distance, for example, four coils are provided on the inner surfaces of the first nut member N1 and the second nut member N2 and around the boss portions B1 and B2. A locking hole 8 for the spring 3a is provided. By locking the coil spring 3a in any of the locking holes 8, the twisting force of the coil spring 3a can be set optimally.
If the coil spring 3a has a reduced diameter as shown in FIG. 2 and generates an urging force in a direction in which the coil spring 3a spreads, the clearance between the boss portions B1 and B2 is always reduced, and the coil spring 3a. The posture becomes easier to stabilize.

The rectangular parallelepiped portions formed on the first nut member N1 and the second nut member N2 function as portions that restrict the nut members from over-rotating with respect to the nut holder 4.
The first nut member N1 and the second nut member N2 are screwed along the screw groove of the screw member 2, and are pressed against the first receiving portion U1 or the second receiving portion U2 to stop. At this time, the frictional force generated between the nut members N1 and N2 and the screw member 2 is basically caused only by the torsional biasing force by the biasing member 3. When the normal engagement of the nut member is performed, when the screw member 2 is driven again, one of the nut members rotates slightly in the direction in which the engagement is released, and the screw member 2 Need to drive smoothly. That is, the urging force of the urging member 3 needs to be limited to such an extent that the nut member can be easily released by re-driving the screw member 2. However, depending on the operation mode of the actuator, some external force may act on the screw member 2, and the nut member may be bitten more than usual when the biting of the nut member is stopped.

  In the self-locking mechanism L of the present embodiment, a restricting portion K is provided in order to prevent the first nut member N1 and the second nut member N2 from over-rotating. In FIG. 3, the function of the said restriction | limiting part K is shown. The left figure in FIG. 3 is a diagram showing a normal biting state of both nut members. Here, both the first nut member N <b> 1 and the second nut member N <b> 2 have a rectangular parallelepiped upper surface parallel to the ceiling surface of the nut holder 4. In the drawing, a line indicating the ceiling 9 of the nut holder 4 is indicated by a thick broken line. In this state, the first nut member N1 and the second nut member N2 are not in contact with the ceiling 9 of the nut holder 4 but are appropriately in contact with the nut holder 4 by the urging force of the urging member 3.

  On the other hand, the right view of FIG. 3 shows a state in which, for example, when the screw member 2 stops driving, an external force is applied to the screw member 2 and the first nut member N1 in front is over-rotated. The right edge of the upper surface of the first nut member N1 is in contact with the ceiling 9 of the nut holder 4. In the present embodiment, the right edge is the first restricting portion K1. In the second nut member N2 on the back side, the left edge is the second restricting portion K2. In this state, a frictional force larger than the frictional force normally generated between the nut members N1 and N2 and the screw member 2 is generated. However, the frictional force is such that it can be released by the next rotational drive of the screw member 2.

  In addition, the structure of the control part K is not restricted to this embodiment. For example, it is good also as a structure contact | abutted over any location of the 1st contact part T1 among the 1st nut members N1, and any location of the 1st receiving part U1 of the nut holder 4. FIG. Further, the first nut member N1 and the second nut member N2 may be in contact with each other when a predetermined phase angle is reached. In short, any configuration may be used as long as the relative phase angle difference between both nut members can be suppressed within a certain range.

As described above, setting the first nut member N1 and the second nut member N2 in the desired state is performed as follows, for example.
As shown in FIG. 2, the nut holder 4 is provided with a first opening 10 perpendicular to the direction of the axis X of the screw member 2 and a second opening parallel to the direction of the axis X. . A first lid member F1 can be attached to the first opening 10, and a second lid member F2 can be attached to the second opening 11. The first lid member F1 is configured to be able to adjust the mounting position with respect to the nut holder 4 using a push screw and a pull screw at each of the four corners. The inner surface of the first lid member F1 functions as a first receiving portion U1 that comes into contact with the first contact portion T1 of the first nut member N1. The surface provided at the back of the nut holder 4 so as to face this functions as a second receiving portion U2 that comes into contact with the second contact portion T2 of the second nut member N2.

First, the first nut member N1, the second nut member N2, and the coil spring 3a are attached to the screw member 2 and temporarily assembled. The interval between the first nut member N1 and the second nut member N2 is adjusted to the preset interval between the first receiving portion U1 and the second receiving portion U2. At this time, the first nut member N1 and the second nut member N2 hold, for example, the same phase against the urging force of the coil spring 3a. For this reason, an appropriate stopper may be engaged across the first nut member N1 and the second nut member N2. The temporarily assembled screw member 2 or the like is inserted from the first opening 10. The hole 12 provided in the wall surface of the nut holder 4 is larger than the outer shape of the screw member 2, and they are not in contact with each other. The second nut member N2 is inserted until it comes into contact with the back second receiving portion U2, and then the first lid member F1 is pushed into a position where it comes into contact with the first nut member N1. In a state where both are in contact, the first cover member F1 is fixed by adjusting the four corner push screws 13 and the pull screws 14. In this state, the stopper is removed, and the first nut member N1 and the second nut member N2 are brought into contact with the first receiving portion U1 and the second receiving portion U2, respectively. The state is confirmed from the second opening 11. At this time, it is desirable that the first nut member N1 and the second nut member N2 are as shown in the left or right diagram of FIG. In this way, the first lid member F1 is fixed at an appropriate position, and the second opening 11 is shielded by the second lid member F2.
However, in this embodiment, since any one of the nut members N1 and N2 needs to rotate slightly with respect to the rotation of the screw member 2, both the first restricting portion K1 and the second restricting portion K2 are nut holders. 4 must not be assembled in contact with the ceiling 9.

[Another embodiment]
As the urging member 3, a first urging member is provided across the first nut member N <b> 1 and the nut holder 4, and a second urging member is provided across the second nut member N <b> 2 and the nut holder 4. May be. That is, various configurations can be freely selected as long as the first nut member N1 and the second nut member N2 are urged to rotate in opposite directions.

  The shape of the urging member 3 is not limited to the coil spring 3a using the twisting force as in the above embodiment. For example, a coil-like long tension spring or compression spring can be used. In this case, for example, a tension (compression) spring can be connected across the outer peripheral portion of the first nut member N1 and the outer peripheral portion of the second nut member N2, and both can be biased.

  The first nut member N1 and the second nut member N2 may be urged in directions close to each other. For example, in FIG. 4, the nut holder 4 is a wall portion 4a provided with a first receiving portion U1 and a second receiving portion U2, and is configured to be sandwiched between a first nut member N1 and a second nut member N2. To do. For example, a cylindrical flange portion is formed around the wall portion 4a to form protective portions for both nut members N1 and N2. When adjusting the phase of the first nut member N1 and the second nut member N2, in order to make the nut members N1 and N2 detachable from the nut holder 4, a part 4b of the flange portion is separately provided. It is good to configure. For example, a slit is formed in the wall portion 4a so that the screw member 2 and both nut members N1 and N2 can be removed at a time by removing a part 4b of the flange portion from the nut holder 4. A part 4b of the flange portion is fixed to the wall portion 4a with, for example, a screw 4c.

In addition, although illustration is abbreviate | omitted, adjustment of the relative phase of the 1st nut member N1 and the 2nd nut member N2 with respect to the nut holder 4 is predetermined | prescribed thickness between each nut member N1, N2 and the wall part 4a, for example. Take measures such as inserting a spacer. Further, a cover member for protecting both the nut member and the coil spring 3a may be provided separately.
With this configuration, it is only necessary to provide one central wall portion 4a as a portion for pressing both nut members N1, N2, so that the configuration of the self-locking mechanism can be simplified.

  The abutting portion of the nut member and the receiving portion of the nut holder 4 may be provided between the outer peripheral surface on the radially outer side of the nut member and the surface parallel to the axis of the inner wall surface of the nut holder 4. Also in this case, since the outer peripheral surface of the nut member abuts against the inner peripheral surface of the nut holder 4 while generating a contact load, the nut member can be moved while the movement of the screw member 2 along the axis X direction is weakened. It will contact the holder 4. That is, also in this case, the reaction force that the nut holder 4 acts on the first nut member N1 and the second nut member N2 gradually increases, and the movement of the nut member in the direction of the axis X is gradually limited. This process is the same as in the above embodiment. Therefore, it is possible to obtain a self-locking mechanism L that is driven smoothly and has a stable stationary posture.

In the above embodiment, the load of the movable table 6 is received by the dedicated guide rail 7. However, the nut holder 4 and the movable table 6 are loaded by the nut members N 1 and N 2 and the screw member 2. May be.
For example, the first nut member N <b> 1 and the second nut member N <b> 2 are formed to protrude outwardly from each other, and a recess that supports these boss portions is provided on the corresponding wall surface of the nut holder 4. For example, such a configuration is also possible if the load acting on the movable table 6 is extremely small and the load does not affect the relative movement between the first nut member N1 and the nut holder 4. In this case, since the guide rail 7 can be omitted, a simpler actuator can be obtained.

  The self-locking mechanism L for an actuator of the present invention can be used as a part of a mechanism unit that performs reciprocating driving, such as a power window of an automobile, an electric sunroof, an electric seat, an electric column, an electric parking brake, and the like. . Moreover, it can use for the mechanism part of not only the component of a motor vehicle but various industrial products.

2 Screw member 3 Biasing member 4 Nut holder 4a Wall part K1 1st control part K2 2nd control part L Self-lock mechanism N1 1st nut member N2 2nd nut member U1 1st receiving part U2 2nd receiving part X Axis core

Claims (5)

A screw member that is rotationally driven;
A first nut member and a second nut member screwed into the screw member;
A biasing member for rotating the first nut member and the second nut member relative to each other;
A nut holder that rotatably holds the first nut member and the second nut member;
The nut holder includes a first receiving portion that restricts axial movement of the first nut member that is rotationally biased by the biasing member, and a shaft of the second nut member that is rotationally biased by the biasing member. A self-locking mechanism for an actuator having a second receiving part for restricting the direction movement.   2. The actuator self-locking mechanism according to claim 1, wherein in the nut holder, at least one of the first receiving portion and the second receiving portion can be adjusted in position. The nut holder includes a first restricting portion that restricts a rotation angle of the first nut member with respect to the nut holder to a predetermined angle;
The actuator self-locking mechanism according to claim 1, further comprising: a second restricting portion that restricts a rotation angle of the second nut member with respect to the nut holder to a predetermined angle.   The first nut member and the second nut member are urged by the urging member in directions away from each other along the axial direction of the screw member, and the first receiving portion and the second receiving portion are The self-locking mechanism for an actuator according to any one of claims 1 to 3, wherein the self-locking mechanism is provided separately on inner walls facing each other of the nut holder.   The first nut member and the second nut member are urged by the urging member in a direction approaching each other along the axial direction of the screw member, and the first receiving portion and the second receiving portion are The actuator self-locking mechanism according to claim 1, wherein the actuator is provided separately on the wall of the nut holder.

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