JP7224145B2 - electric actuator - Google Patents

Description

The present invention relates to an electric actuator.

In recent years, the electrification of vehicles has progressed in order to save labor and improve fuel efficiency. For example, systems that use the power of electric motors to operate automatic transmissions, brakes, steering, etc. of automobiles have been developed and put on the market. .

In the electric actuator used for such applications, if a load is applied to the electric actuator from the side of the device to be operated while the electric actuator is stopped, the load (reverse input from the output side to the input side) causes the electric actuator to move. There is a problem that the actuator operates. Therefore, conventionally, in order to prevent the operation of the electric actuator due to such a reverse input from the operation target side, a lock mechanism has been proposed.

For example, Patent Literature 1 below discloses a configuration for preventing the operation of an electric actuator due to a reverse input by restricting the rotation of a drive gear that transmits the driving force of an electric motor. Specifically, this electric actuator includes a lock member that advances and retreats in the axial direction with respect to the drive gear. By inserting it into one of them, the rotation of the drive gear is restricted. Accordingly, even if there is a reverse input from the output side to the input side, the operation of the electric actuator is prevented, and the operation target can be held at the desired operation position.

JP 2017-184484 A

However, in the configuration described above, in which the lock member is moved in the axial direction of the drive gear and its tip is inserted into the engagement hole, the phase in the rotation direction of the engagement hole and the position of the tip of the lock member are not accurate. If they do not fit well, there is a possibility that the tip of the lock member will not be inserted into the engagement hole, which poses a problem of operational stability. Therefore, complicated control is required to match the phases of the engagement hole and the locking member. Moreover, when a large reverse input load acts, stress concentrates on the tip portion of the locking member, so there is also a problem that the tip portion is likely to be worn.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an electric actuator in which the operation stability and durability of a reverse input lock mechanism are improved.

In order to solve the above problems, the present invention provides a drive motor, a motion conversion mechanism for converting rotary motion of the drive motor into linear motion, a transmission gear for transmitting the rotary motion of the drive motor to the motion conversion mechanism, and a lock mechanism for preventing operation of the electric actuator due to a reverse input from the motion conversion mechanism to the drive motor, wherein the lock mechanism is positioned relative to at least one of the rotation shaft of the drive motor and the transmission gear. It is characterized by comprising a locking member that engages with a plurality of engaging teeth of the engaging portion by moving radially with respect to the engaging portion that is provided so as not to rotate.

As described above, in the electric actuator according to the present invention, the lock member is configured to move in the radial direction and engage with the engaging portion. The engagement of the lock member with the engagement portion is easier than in the case of inserting the lock member into the engagement hole of the drive gear. Therefore, the locking member and the engaging portion can be engaged even if the position of the locking member and the phase of the engaging portion in the rotational direction are not matched with high accuracy, and the operational stability is improved. Further, since the lock member according to the present invention engages with the plurality of engagement teeth of the engagement portion, it can receive a reverse input load at the plurality of engagement points. Therefore, the durability is improved as compared with the conventional structure in which only the front end portion of the lock member receives the reverse input load.

The locking mechanism includes, for example, a locking motor as a driving source, so that the driving force of the locking motor can move the locking member in the radial direction.

Further, since the locking mechanism includes a biasing member that biases the locking member in a direction to release the engagement state between the locking member and the engaging portion, when the locking motor is energized, the locking mechanism is activated. When the lock member is radially moved by the driving force of the motor and engaged with the engaging portion, and the locking motor is de-energized, the locking member and the engaging portion are separated by the biasing force of the biasing member. It can be configured such that the engagement with is released.

In addition, since the lock mechanism includes a cam that is rotated by the driving force of the lock motor, the cam can be rotated to push and move the lock member in the radial direction.

Moreover, it is desirable that the lock mechanism include a cam supporting member that contacts the outer peripheral surface of the cam to support the cam. By the cam support member supporting the cam against the force received from the lock member side, it is possible to prevent displacement of the cam and to exhibit the function of the cam satisfactorily. In particular, since the cam support member receives the reaction force generated in the lock member when the lock member is engaged with the engagement portion, the engagement force between the lock member and the engagement portion is improved. Rotation of the engaging portion (operation of the electric actuator) can be prevented more firmly.

Further, the lock mechanism includes a circumferential restriction portion that restricts movement of the lock member in the circumferential direction by abutting against a circumferential end face of the lock member while the lock member is engaged with the engagement portion. It is desirable to have In this manner, the circumferential movement of the locking member is restricted by the circumferential direction restricting portion, so that the rotational displacement of the engaging portion with which the locking member engages can be prevented. As a result, it is possible to more reliably prevent the operation of the electric actuator when there is a reverse input, and it is possible to maintain the operation position of the operation target at a high level.

It is desirable that the engaging tooth is formed in a triangular shape having two straight sides that approach toward the tip, and that the opening angle of the engaging tooth is set to 90° or more. By setting the shape and the opening angle of the engaging teeth in this way, it becomes possible to release the engagement of the locking member with the engaging teeth more smoothly than in the case where the engaging teeth are formed to have an involute tooth profile.

According to the present invention, since the operation stability and durability of the lock mechanism can be improved, the function can be satisfactorily exhibited over a long period of time, and a highly reliable electric actuator can be provided. become.

1 is a longitudinal sectional view of an electric actuator according to an embodiment of the invention; FIG. FIG. 2 is an enlarged vertical cross-sectional view of the lock mechanism and its peripheral portion shown in FIG. 1; FIG. 3 is a transverse cross-sectional view of the locking mechanism taken along line XX in FIG. 2, showing an unlocked state of the locking mechanism; FIG. 3 is a cross-sectional view of the locking mechanism taken along line XX in FIG. 2, showing a locked state of the locking mechanism; FIG. 4 is an enlarged cross-sectional view showing each engagement tooth of the lock member and the engagement portion;

FIG. 1 is a longitudinal sectional view of an electric actuator according to one embodiment of the invention. First, referring to FIG. 1, the overall configuration and operation of the electric actuator according to this embodiment will be described.

The electric actuator 1 shown in FIG. 1 includes a driving portion 2 having a driving motor 5, a driving force transmission mechanism 3 that transmits the rotational motion of the driving motor 5, and a linear motion that converts the rotational motion of the driving motor 5. The main components are a motion conversion mechanism 4 and a lock mechanism 6 that prevents the electric actuator 1 from operating due to a reverse input from the motion conversion mechanism 4 side (output side) to the drive motor 5 side (input side).

The drive unit 2 includes a drive motor 5, a pair of busbars 70 as conductive members for supplying power to the drive motor 5, and a motor case 60 that houses the drive motor 5, the busbars 70, and the like. . In this embodiment, an inexpensive DC motor (with a brush) is used as the drive motor 5, but other motors such as a brushless motor may be used. It should be noted that the motor case 60 here is configured separately from the case (housing) of the driving motor 5 itself, and is an electric actuator housing the entire driving motor 5 having its own case. Case (actuator case).

The motor case 60 is composed of a cylindrical main body 61 that houses most of the driving motor 5 and a lid-like cap 62 that is fixed to one end of the main body 61 (the left end in FIG. 1). ing. Each bus bar 70 is formed by bending a metal plate member into a predetermined shape, and is held by a holder portion 71 made of resin. Each bus bar 70 is welded to a motor terminal (not shown) of the driving motor 5 while the holder portion 71 is fixed to the end (the left end in FIG. 1) of the driving motor 5. ing. The cap portion 62 is provided with a cylindrical connector portion 62a protruding in the axial direction, and on the inner peripheral side of the connector portion 62a, the distal end portions of the bus bars 70 (on the side opposite to the side connected to the motor terminal). end) are placed. By connecting a mating terminal of a power line extending from a power source (not shown) to the tip of the bus bar 70 , power can be supplied from the power source to the drive motor 5 .

The driving force transmission mechanism 3 is composed of a driving side drive gear 8 as a first transmission gear and a driven side driven gear 9 as a second transmission gear that meshes with the driving side drive gear 8 . The drive gear 8 and the driven gear 9 are housed inside the gear case 10 . The drive gear 8 is a small-diameter gear having fewer teeth than the driven gear 9, and is attached to the rotating shaft 5a of the drive motor 5 so as to rotate integrally therewith. On the other hand, the driven gear 9 is a large-diameter gear with more teeth than the drive gear 8, and is attached to a nut 17 (to be described later) that constitutes the motion conversion mechanism 4 so as to rotate integrally therewith. ing.

The drive gear 8 is rotatably supported by a bearing 11 arranged on one side in the axial direction (the left side in FIG. 1). The bearing 11 is held by being fitted in a cylindrical bearing holding member 13 fixed to the end of the drive motor 5 . The other axial side of the drive gear 8 (the right side in FIG. 1) is indirectly supported by a bearing 12 that supports a rotary shaft 5a projecting from the drive gear 8 in the axial direction. This bearing 12 is held by being fitted in the gear case 10 . In this embodiment, one bearing 11 is a ball bearing and the other bearing 12 is a needle roller bearing.

The driven gear 9 is rotatably supported together with the nut 17 by double-row bearings 14 provided on the outer peripheral surface of the nut 17 . The double-row bearing 14 is accommodated in a cylindrical sleeve 15 provided in the gear case 10, and its axial movement is restricted by a stepped portion provided on the inner peripheral surface of the sleeve 15 and the outer peripheral surface of the nut 17. ing. As the double-row bearing 14, it is preferable to use a double-row angular contact ball bearing capable of supporting an axial load in both directions in addition to a radial load so that the nut 17 can be stably and reliably supported.

When the drive motor 5 starts driving and the rotation shaft 5a of the drive motor 5 rotates, the drive gear 8 rotates integrally with the rotation shaft 5a, and the driven gear 9 rotates in conjunction therewith. At this time, since the rotational motion from the drive motor 5 is transmitted from the drive gear 8 with a small number of teeth to the driven gear 9 with a large number of teeth, the rotational torque is reduced and the rotational torque is increased. Note that unlike the present embodiment, the drive gear 8 and the driven gear 9 may be configured with gears having the same number of teeth so that the rotational motion from the driving motor 5 is transmitted without being reduced.

The motion conversion mechanism 4 is a ball screw mechanism having a nut 17 as a rotating member, a screw shaft 18 as a linear motion member, and a large number of balls 19 . Spiral grooves are formed on the inner peripheral surface of the nut 17 and the outer peripheral surface of the screw shaft 18, respectively, and the balls 19 are accommodated between these spiral grooves so as to be able to roll. A circulating member 16 is provided on the nut 17, and the circulating member 16 is configured to circulate the balls 19 along the spiral groove.

The screw shaft 18 is inserted through the inner circumference of the nut 17 and arranged parallel to the rotating shaft 5 a of the driving motor 5 . A connecting hole 18a is provided at the front end portion (the left end portion in FIG. 1) of the screw shaft 18, and by inserting a fastener such as a bolt into the connecting hole 18a, the screw shaft 18 and the operation target shown in the figure can be operated. It is connected to the corresponding part of the equipment that does not use it. When the rotational motion of the driving motor 5 is transmitted to the nut 17 via the drive gear 8 and the driven gear 9, the nut 17 rotates, thereby moving the screw shaft 18 in one axial direction (forward direction or backward direction). do. Conversely, when the driving motor 5 rotates in the reverse direction, the rotational motion is transmitted to the nut 17 via the drive gear 8 and the driven gear 9, and the screw shaft 18 moves in the other axial direction. In this manner, the screw shaft 18 advances or retreats due to forward and reverse rotation of the drive motor 5 , thereby operating the operation target connected to the front end portion of the screw shaft 18 .

The rear end of the screw shaft 18 (the end opposite to the end on the operation target side) is covered with a screw shaft case 20 . The screw shaft case 20 is fixed to the gear case 10 on the side opposite to the side to which the motor case 60 is fixed.

A rotation stop pin 21 is provided at the rear end of the screw shaft 18 as a rotation restricting member for restricting rotation of the screw shaft 18 . The anti-rotation pin 21 is attached to the screw shaft 18 in a direction perpendicular to or crossing the axial direction thereof. Guide rollers 22 are rotatably attached to both ends of a detent pin 21 protruding radially from the rear end of the screw shaft 18 . Each guide roller 22 is inserted into a pair of axially extending guide grooves 20 a provided in the screw shaft case 20 . As the guide roller 22 moves in the axial direction along the guide groove 20a, the screw shaft 18 advances or retreats in the axial direction without rotating in the circumferential direction.

A boot 23 for preventing foreign matter from entering the electric actuator 1 and a boot cover 25 for protecting the boot 23 are provided on the screw shaft 18 on the front end side of the nut 17 . . The boot 23 is composed of a small-diameter end portion 23a, a large-diameter end portion 23b, and a bellows portion 23c connecting these ends and extending and contracting in the axial direction. The small-diameter end portion 23a is fixed to the outer peripheral surface of the screw shaft 18, and the large-diameter end portion 23b is fixed to the outer peripheral surface of a cylindrical boot mounting member 24 attached to the boot cover 25. As shown in FIG. The boot cover 25 is arranged to cover the outside of the boot 23 and is molded integrally with the main body 61 of the motor case 60 .

A magnet 27 that serves as a sensor target for detecting the axial position of the screw shaft 18 is provided on the outer peripheral surface of the screw shaft 18 . On the other hand, a stroke sensor (not shown) is provided on the outer circumference of the motor case 60 . When the screw shaft 18 advances or retreats, the stroke sensor detects changes in the magnetic field (for example, the direction and strength of magnetic flux density) of the magnet 27 that moves along with this, thereby detecting the axial position of the magnet 27 and thus the screw shaft. Eighteen axial positions are detected.

Next, the configuration of the locking mechanism 6, which is a feature of the present invention, will be described with reference to FIGS. 2 to 4. FIG.

2 is a longitudinal sectional view showing the locking mechanism 6 shown in FIG. 1 and its peripheral portion in an enlarged manner, and FIGS. 3 and 4 are transverse sectional views of the locking mechanism 6 taken along the line XX in FIG. 3 is a diagram showing the unlocked state of the lock mechanism 6, and FIG. 4 is a diagram showing the locked state of the lock mechanism 6. As shown in FIG.

2 and 3, the lock mechanism 6 includes a lock member 30, a cam 31 that pushes and moves the lock member 30, a lock motor 32 (see FIG. 2) that rotates the cam 31, and the lock member 30. a pair of biasing members 33 (see FIG. 3) for biasing, a biasing support member 34 for supporting the biasing members 33, and a cam support member 35 for supporting the cam 31.

As shown in FIG. 3, the lock member 30 is formed of an arc-shaped member, and has a plurality of engaging teeth 30a arranged circumferentially on its inner peripheral surface. An engaging portion 40 that is provided integrally with the drive gear 8 and fixed to the rotating shaft 5a of the driving motor 5 is arranged on the inner diameter side of the locking member 30. It is configured to be radially movable (approachable/separable) with respect to. The engaging portion 40 may be separate from the drive gear 8 as long as it is provided so as not to rotate relative to at least one of the rotating shaft 5a of the drive motor 5 and the drive gear 8. . In addition, a plurality of engaging teeth 40 a are provided along the entire outer peripheral surface of the engaging portion 40 in the same manner as the engaging teeth 30 a of the locking member 30 . When the engaging teeth 30a of the locking member 30 engage with the engaging teeth 40a of the engaging portion 40, the locked state shown in FIG. 4 is achieved.

As shown in FIG. 2 , a stepped portion 41 and a ring-shaped stopper member 42 are provided on the outer peripheral surface of the engaging portion 40 . The stepped portion 41 and the stopper member 42 are provided on one side and the other side of the lock member 30 in the axial direction, and function as axial direction restricting portions that restrict axial movement of the lock member 30 with respect to the engaging portion 40 . do. As a result, the lock member 30 is held facing the engagement teeth 40 a of the engagement portion 40 .

The cam 31 is fixed to the rotating shaft 32a of the locking motor 32 and configured to rotate together with the rotating shaft 32a. As shown in FIG. 3, the cam 31 has an arc-shaped cam surface 31a arranged eccentrically with respect to its rotation center (the center of the rotation shaft 32a) and a flat surface 31b continuous with the cam surface 31a. and On the other hand, the outer peripheral surface of the lock member 30 is provided with a cam action surface 30b with which the cam surface 31a contacts, and a flat cam stopper surface 30c that cooperates with the flat surface 31b of the cam 31 to restrict the rotation of the cam 31. ing.

As shown in FIG. 2 , the locking motor 32 is housed in a cylindrical motor housing portion 51 provided in the screw shaft case 20 . A cap member 52 is attached to the motor accommodating portion 51 to seal an opening at one end thereof. In this embodiment, a DC motor (with a brush) that is smaller than the drive motor 5 is used as the locking motor 32, but other motors such as a brushless motor may be used.

As shown in FIG. 3, the pair of biasing members 33 are provided at both circumferential ends 34b and 34c of a biasing support member 34 formed in an arc shape (C shape). In the present embodiment, concave portions 34a are provided at both ends 34b and 34c in the circumferential direction of the biasing support member 34, and the biasing member 33 is attached to each concave portion 34a. Each biasing member 33 biases the locking member 30 in a direction away from the engaging portion 40 by pushing the circumferential direction end faces 30 d and 30 e of the locking member 30 . In this embodiment, a leaf spring is used as the biasing member 33, but other spring members such as coil springs or elastic bodies such as rubber may be used.

The cam 31 is in contact with the inner peripheral surface of a semicircular cam support member 35 on the side opposite to the side that contacts the lock member 30 . Since the cam 31 is in contact with the inner peripheral surface of the cam support member 35 in this manner, the cam 31 is supported against the force received from the lock member 30 side.

As shown in FIG. 2 , the urging support member 34 and the cam support member 35 are provided inside the gear case 10 . Although the urging support member 34 and the cam support member 35 are configured separately from the gear case 10 in this embodiment, they may be configured integrally with the gear case 10 . In this embodiment, the case of the electric actuator 1 is composed of the motor case 60 consisting of the body portion 61 and the cap portion 62, the gear case 10, the screw shaft case 20, and the boot cover 25. The structure of the case is not limited to this. The shape and division structure of the case can be changed as appropriate according to changes in the specifications of the internal structure of the electric actuator, ease of assembly, and the like. Therefore, the urging support member 34 and the cam support member 35 may be configured integrally with a case other than the gear case 10 . Both the biasing support member 34 and the cam support member 35 are long in the circumferential direction (C-shaped or semicircular). It may be shorter than the force support member 34 and cam support member 35 .

Next, operation of the lock mechanism 6 will be described.

First, in the unlocked state shown in FIG. 3 , the locking motor 32 is not energized and the torque of the locking motor 32 is not applied to the cam 31 . Therefore, the locking member 30 is held in a state of being separated from the engaging portion 40 by the biasing force of the biasing member 33 without receiving the driving force from the cam 31 . Thus, in the unlocked state, the locking member 30 is separated from the engaging portion 40 , so the engaging portion 40 is not restrained by the locking member 30 . Therefore, the engaging portion 40 is in a state in which it can freely rotate clockwise and counterclockwise in FIG. is possible. In the unlocked state, the rotation of the cam 31 is restricted by the contact between the flat surface 31b and the cam stopper surface 30c, and is held at a predetermined rotational phase.

When the lock motor 32 is energized in such an unlocked state, the cam 31 rotates to push the lock member 30 as shown in FIG. At this time, the drive motor 5 is stopped, and the electric actuator 1 is not operated. As shown in FIG. 4, the cam surface 31a pushes the cam action surface 30b of the lock member 30 against the biasing force of the biasing member 33 by rotating the cam 31 clockwise. As a result, the locking member 30 is pushed toward the engaging portion 40 (inner diameter direction), and the plurality of engaging teeth 30a of the locking member 30 engage the engaging portions 40 facing each other. It engages against teeth 40a. At the same time, both circumferential end surfaces 30 d and 30 e of the lock member 30 abut against both end portions 34 b and 34 c of the urging support member 34 . As a result, movement of the locking member 30 to both sides in the circumferential direction is restricted, and displacement of the engaging portion 40 with which the locking member 30 engages is also restricted in the rotational direction. In this manner, the locking member 30 is engaged with the engaging portion 40, and the circumferential movement of the locking member 30 is restricted, whereby the rotation of the engaging portion 40 is restricted (locked state). becomes. In this state, the rotation of the rotary shaft 5a of the drive motor 5 and the drive gear 8 are also restricted, so even if there is a reverse input to the electric actuator 1 from the operation target side, the operation of the electric actuator 1 is prevented. The object is held in a predetermined operating position.

In addition, in order to return from the locked state to the unlocked state, the power supply to the locking motor 32 is cut off. As a result, the locking member 30 is pushed away from the engaging portion 40 (outer diameter direction) by the biasing force of the biasing member 33 because the cam 31 no longer presses the locking member 30 . Then, the engagement between the locking member 30 and the engaging portion 40 is released, and the engaging portion 40 is brought into a state (unlocked state) in which the engaging portion 40 can freely rotate. Further, as the locking member 30 is pushed away from the engaging portion 40, the cam 31 rotates counterclockwise in FIG. The contact is held in a state in which rotation is restricted.

As described above, in the lock mechanism 6 according to the present embodiment, the lock member 30 is moved in the radial direction instead of being moved in the axial direction and inserted into the engagement hole of the drive gear as in the conventional structure. By doing so, it becomes easier to engage the lock member 30 with the engaging portion 40 . Therefore, the engagement teeth 30a, 40a of the lock member 30 and the engagement portion 40 can be engaged with each other without being precisely aligned with each other, thereby improving the operational stability. In the present embodiment, the rotation of the locking motor 32 is mechanically stopped by engaging the locking member 30 with the engaging portion 40 . A sensor for detecting the amount of rotation of the motor 32 is not required.

Further, in the locking mechanism 6 according to the present embodiment, the plurality of engaging teeth 30a, 40a are engaged with each other (a plurality of Since a reverse input load can be received at the engagement point, it is possible to avoid stress concentration when there is only one engagement point. As a result, wear of the lock member 30 due to reverse input can be suppressed, and durability against reverse input load can be improved.

Furthermore, in the locking mechanism 6 according to the present embodiment, when the locked state is established, the circumferential direction end portions 34b and 34c of the urging support member 34 contact the circumferential direction end faces 30d and 30e of the lock member 30 as described above. By abutting, it functions as a circumferential direction restricting portion that restricts the circumferential movement of the lock member 30 . In this way, the urging support member 34 functions as a circumferential direction restricting portion that restricts the circumferential movement of the lock member 30 in the locked state. Displacement can be reliably prevented. Therefore, in the present embodiment, it is possible to reliably prevent the operation of the electric actuator 1 due to a reverse input, and to highly maintain the operation position of the operation target.

In addition, like the lock mechanism 6 according to the present embodiment, by providing the cam support member 35 that supports the cam 31 against the force received from the lock member 30 side, the bending load on the rotating shaft 32a of the lock motor 32 is reduced. can be reduced, and deformation of the rotating shaft 32a can be prevented. The cam support member 35 may be omitted if the bending load on the rotating shaft 32a is within an allowable range. Further, since the cam support member 35 is provided, it is possible to prevent the cam 31 from being displaced by the force received from the lock member 30 side, and the function of the cam 31 to push and move the lock member 30 can be exhibited satisfactorily. . Here, the force received from the locking member 30 includes not only the biasing force of the biasing member 33 but also the reaction force received from the engaging portion 40 when the locking member 30 engages with the engaging portion 40 . In particular, since the cam 31 is supported by the cam support member 35 against the reaction force that the locking member 30 receives from the engaging portion 40, the engaging force between the locking member 30 and the engaging portion 40 is improved. Rotation of the engaging portion 40 during input can be prevented more firmly.

In the present embodiment, the engagement teeth 30a, 40a of the locking member 30 and the engagement portion 40 are formed in a triangular shape having two linear sides that approach toward the tip. , 40a (see FIG. 5) are desirably set to 90° or more. By setting the shape and opening angles α and β of each of the engaging teeth 30a and 40a in this way, the separation between the engaging teeth 30a and 40a is improved as compared with the case where these are formed into an involute tooth profile. , the engaged state can be released smoothly. The shape of each engagement tooth 30a, 40a is not limited to that of the present embodiment, and may be changed as appropriate.

Although the embodiments of the electric actuator according to the present invention have been described above, the present invention is not limited to the above-described embodiments.

In the above-described embodiment, when the locking motor 32 is energized, the locking member 30 is radially pushed by the cam 31 to engage with the engaging portion 40, and the locking motor 32 is released. Although the engagement between the lock member 30 and the engaging portion 40 is released by the biasing force of the biasing member 33 when the electric current is turned on, it may be configured to operate in the opposite direction. That is, when the locking motor 32 is in a non-energized state, the locking member 30 is engaged with the engaging portion 40 by the biasing force of the biasing member 33, and the locking motor 32 is in a energized state. Alternatively, the locking member 30 may be pushed by the cam 31 to release the engagement between the locking member 30 and the engaging portion 40 .

In the above-described embodiment, the cam 31 is always in contact with the cam support member 35. However, the diameter of the outer peripheral surface of the cam 31 is varied in the rotational direction so that the cam 31 is in contact with the cam support member 35. There may be timings when contact is not made with respect to For example, when the locking member 30 is pushed, the cam 31 initially rotates in a non-contact manner with respect to the cam support member 35, and the cam 31 rotates when or before the locking member 30 engages with the engaging portion 40. may contact the cam support member 35 . By preventing the cam 31 from coming into contact with the cam support member 35 when the rotation of the cam 31 is started in this manner, sliding resistance of the cam 31 against the cam support member 35 can be avoided. Further, even in a configuration in which the cam 31 is always in contact with the cam support member 35, from the viewpoint of reducing the sliding resistance of the cam 31, when the lock member 30 is engaged with the engaging portion 40, Except for , it is desirable that the cam 31 is in contact with the cam support member 35 with as little pressure as possible.

Further, unlike the above-described embodiment, it is also possible to use the driving force transmission teeth (which mesh with the driven gear 9) of the drive gear 8 as engagement teeth 40a (engagement portions 40) with which the lock member 30 engages. It is possible. Further, the engaging portion 40 is provided integrally or separately with respect to the driven gear 9 instead of the drive gear 8 so as not to rotate relative to the engaging portion 40, and the lock member 30 can be engaged with the engaging portion 40. You may

In the above-described embodiment, the lock motor 32 whose rotation axis is arranged parallel to the rotation axis 5a of the drive motor 5 is used as the drive source for the lock member 30, and the rotation of the lock motor 32 is controlled by the cam 31. is converted into radial motion of the lock member 30, it is needless to say that other drive sources, link mechanisms, and the like can be appropriately adopted according to the layout of the parts constituting the electric actuator 1, and the like.

Moreover, the configuration according to the present invention is not limited to the electric actuator 1 according to the above-described embodiment, and can be applied to other electric actuators such as those having a planetary gear reducer or the like.

REFERENCE SIGNS LIST 1 electric actuator 2 driving unit 3 driving force transmission mechanism 4 motion conversion mechanism 5 driving motor 6 lock mechanism 8 drive gear (first transmission gear)
9 driven gear (second transmission gear)
30 locking member 30a engaging tooth 30d circumferential end face 30e circumferential end face 31 cam 32 locking motor 33 biasing member 34 biasing support member 34b circumferential end (circumferential direction restricting portion)
34c Circumferential direction end (circumferential direction regulation part)
35 cam support member 40 engagement portion 40a engagement tooth α opening angle β opening angle

Claims (5)

a driving motor; a motion converting mechanism for converting rotary motion of the driving motor into linear motion; a transmission gear for transmitting the rotary motion of the driving motor to the motion converting mechanism; An electric actuator comprising a lock mechanism that prevents operation of the electric actuator due to a reverse input to the side of the motor,
The lock mechanism moves radially with respect to an engaging portion provided so as not to rotate relative to at least one of the rotation shaft of the driving motor and the transmission gear, thereby a lock member that engages with a plurality of engagement teeth; a cam that rotates to push and move the lock member toward the engagement teeth; and a cam support member that supports the cam,
The cam support member is provided on the outer periphery of the cam on the side opposite to the side where the lock member and the cam contact with the lock member engaged with the engagement portion, with respect to the rotation shaft of the cam. An electric actuator that contacts a surface and supports the cam against a force received from the lock member side . 2. The electric actuator according to claim 1, wherein the locking mechanism includes a locking motor that applies a driving force for radially moving the locking member. The locking mechanism includes a biasing member that biases the locking member in a direction to release the engagement state between the locking member and the engaging portion,
when the locking motor is energized, the locking member is radially moved by the driving force of the locking motor and engaged with the engaging portion;
3. The electric actuator according to claim 2, wherein the engagement between the lock member and the engaging portion is released by the biasing force of the biasing member when the locking motor is in a non-energized state. The lock mechanism is configured to restrict movement of the lock member in the circumferential direction by contacting a circumferential end face of the lock member while the lock member is engaged with the engaging portion. The electric actuator according to any one of claims 1 to 3, comprising a direction restricting portion . 5. Any one of claims 1 to 4, wherein the engaging tooth is formed in a triangular shape having two straight sides that approach toward the tip, and the opening angle of the engaging tooth is set to 90° or more. The electric actuator according to the paragraph .

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