JP2022053024A - Electric actuator - Google Patents

Abstract

To regulate a movable range of an output axis between two points without an occurrence of noises and breakage of members.SOLUTION: An electric actuator 1 has an electric motor 2, a speed reducing gear 3 reducing speed of a rotation of the electric motor 2 to be output, a swing member 11 swinging with the rotation of the electric motor 2, an output axis 14 rotating by swinging of the swing member 11, and a detection mechanism 30. The detection mechanism 30 detects a movement of a movable member within the electric actuator 1, and regulates a rotation range of the output axis 14 within a range of two points from a position of one side of a rotation direction to a position of the other side by a detection result of the detection mechanism 30.SELECTED DRAWING: Figure 2

Description

The present invention relates to an electric actuator.

In recent years, motorization has progressed in order to save labor and reduce fuel consumption of vehicles, and for example, a system for operating automatic transmissions, brakes, steering, etc. of automobiles with the power of electric motors has been developed and put on the market. ..

As an electric actuator used for such an application, for example, in Patent Document 1, as shown in FIG. 12, the first method of converting the rotational motion of the electric motor 300 into linear motion (movement in the directions of arrows A1 and A2 in the figure). The second motion conversion that converts the linear motion of the motion conversion mechanism 100 and the first motion conversion mechanism 100 into rotational motion (movement in the directions of arrows B1 and B2 in the figure) of the axis orthogonal to the rotation axis of the electric motor 300. An electric actuator with a mechanism 200 is disclosed. Specifically, the first motion conversion mechanism 100 is composed of a sliding screw mechanism having a screw shaft 101 as a rotating member and a nut 102 as a linear motion member screwed with the screw shaft 101. On the other hand, the second motion conversion mechanism 200 is composed of a swing member 201 having a cylindrical portion 201a and an arm portion 201b. An elongated hole 201c is provided in the arm portion 201b, and by inserting a pin-shaped connecting member 202 provided in the nut 102 into the elongated hole 201c, the swing member 201 and the nut 102 can be interlocked with each other. Has been done.

When the screw shaft 101 rotates forward or reverse by driving the electric motor 300, the nut 102 moves in the direction of arrow A1 or the direction of arrow A2, so that the rotary motion is converted into a linear motion. Then, as the nut 102 moves, the swing member 201 swings in the direction of arrow B1 or the direction of arrow B2 about the cylindrical portion 201a, so that the linear motion rotates on an axis orthogonal to the rotation axis of the electric motor 300. Converted into exercise.

Further, in the electric actuator described in Patent Document 1, protrusions 102a and 400a are provided on both end faces of the nut 102 and on the end faces of the thrust bearings 400 facing the nut 102, respectively. When the nut 102 moves in the direction of arrow A1 or the direction of arrow A2, the nut 102 approaches the thrust bearing 400 in the moving direction, so that the protruding portion 102a of the nut 102 and the protruding portion 400a of the thrust bearing 400 come into contact with each other. At this time, since the protruding portion 400a of the thrust bearing 400 rotates together with the screw shaft 101, the protruding portion 102a of the nut 102 and the protruding portion 400a of the thrust bearing 400 engage with each other in the rotational direction. As a result, the rotation of the screw shaft 101 is restricted, and the movement of the nut 102 and the swing of the swing member 201 on the output side are restricted.

Japanese Unexamined Patent Publication No. 2019-97352

If it is desired to operate the member on the output side within a predetermined range, it is sufficient to regulate the member at two points, one end on one side and the other end in the operation direction. Therefore, as in Patent Document 1, by engaging the swinging member with other members at both ends in the swinging direction, it is possible to adopt a configuration that regulates the movable range of the swinging member, which is simple. The movable range of the member can be regulated by such a configuration.

However, in the configuration of Patent Document 1, it is necessary to secure the strength of the engaged portion of the member in order to prevent noise due to the impact when the members are engaged with each other and damage due to the collision. There was a problem that the cost would increase.

From the above, it is an object of the present invention to regulate the movable range of the output shaft between two points without generating noise or damaging the members.

In order to solve the above problems, the present invention comprises an electric motor, a speed reducer that decelerates and outputs the rotation of the electric motor, a swing member that swings with the rotation of the electric motor, and the swing. An electric actuator including an output shaft that rotates due to the swing of a member and a detection mechanism. The detection mechanism detects the operation of a movable member in the electric actuator, and the detection result of the detection mechanism is used to detect the movement of the movable member. It is characterized in that the rotation range of the output shaft is restricted to the range between two points from the position on one side to the position on the other side in the rotation direction.

According to the present invention, the rotation angle of the output shaft can be calculated by detecting the amount of movement of the movable member by using the detection mechanism, and the rotation range of the output shaft can be regulated. As described above, in the present invention, for an electric actuator having a sufficient configuration in which the output shaft is regulated at two positions, a configuration is intentionally adopted in which the operating amount of the output shaft is calculated and the operating range is regulated. .. As a result, the rotation range of the output shaft can be regulated without causing collision between the members, and noise generation, wear and tear of the members can be prevented. Further, in order to prevent the wear and tear of these members, it is not necessary to excessively reinforce the strength of the members. Therefore, the cost of the member can be suppressed.

It further includes a screw shaft that rotates by the output of the reducer and a linear motion member that linearly moves in the axial direction by the rotation of the screw shaft and swings the swing member. The detection mechanism includes a detection unit and a linear motion member. It can be an electric actuator including a detected portion detected by the detection unit.

The electric motor includes a rotating shaft, and the detection mechanism can be an electric actuator including a detection unit and a detected unit provided on the rotating shaft and detected by the detection unit.

It is further equipped with a screw shaft that rotates by the output of the speed reducer, a bearing that rotatably supports the screw shaft, and a linear motion member that linearly moves in the direction of the rotation axis by the rotation of the screw shaft and swings the swing member. The detection mechanism can be an electric actuator including a detection unit and a detected unit provided on the bearing and detected by the detection unit.

It further includes a screw shaft that rotates by the output of the speed reducer and a linear motion member that linearly moves in the direction of the rotation axis by the rotation of the screw shaft and swings the swing member. The detection mechanism includes a detection unit and a screw shaft. It can be an electric actuator including a detected portion detected by the detection unit.

A screw shaft that rotates by the output of the speed reducer and a linear motion member that linearly moves in the axial direction by the rotation of the screw shaft and swings the swing member are further provided. It can be an electric actuator provided and includes a detected portion detected by the detection unit.

The electric motor is a brushless motor, and can be an electric actuator provided in the brushless motor and having a rotation detection mechanism for detecting the rotation position of the brushless motor as a detection mechanism.

According to the present invention, the rotation range of the output shaft can be regulated within the range between two points without causing noise, wear or breakage of members, or the like.

It is a perspective view of the electric actuator which concerns on one Embodiment of this invention. It is a vertical sectional view of an electric actuator. It is a block diagram of an electric actuator. The figures (a) and (b) are diagrams showing the movement of the magnet accompanying the linear motion of the nut. It is a figure which shows the relationship between the output voltage of a Hall element, and the rotation angle of an output shaft. It is a vertical sectional view of the electric actuator of a different embodiment. It is a vertical sectional view of the electric actuator of a different embodiment. It is a vertical sectional view of the electric actuator of a different embodiment. It is a vertical sectional view of the electric actuator of a different embodiment. It is a vertical sectional view of the electric actuator of a different embodiment. It is a figure which shows the structure of a brushless motor. It is a vertical sectional view which shows the conventional electric actuator.

Hereinafter, embodiments according to the present invention will be described with reference to the drawings. In each figure, the same or corresponding parts are designated by the same reference numerals, and the duplicated description thereof will be appropriately simplified or omitted.

FIG. 1 is a perspective view of an electric actuator according to an embodiment of the present invention, and FIG. 2 is a vertical sectional view of the electric actuator according to the present embodiment.

As shown in FIG. 1, the electric actuator 1 according to the present embodiment has a linear motion of an electric motor 2, a speed reducer 3 that decelerates and outputs the rotation of the electric motor 2, and a rotary motion output from the speed reducer 3. The first motion conversion mechanism 4 that converts to It mainly includes a mechanism 5 and a housing 6 for accommodating them.

In this embodiment, a small motor such as a brushed motor is used as the electric motor 2. The electric motor 2 is connected to an external power supply (not shown) via a relay circuit (provided in the lid 29 of FIG. 2) which is a switching element provided in the housing 6. A motor holder 16 for holding the electric motor 2 is provided on one end side (reducer 3 side) in the axial direction of the electric motor 2. The motor holder 16 is assembled to the housing 6. As a result, the electric motor 2 is supported by the housing 6 via the motor holder 16. Further, the motor holder 16 and the electric motor 2 are fixed by a plurality of bolts 17 (see FIG. 2) as fixing members.

The housing 6 is configured by assembling two housing split bodies 60. FIG. 1 shows a state in which one of the two housing divisions 60 is removed from the other. By assembling the housing divisions 60 to each other via a sealing member (not shown) between the mating surfaces, the internal space of the housing 6 is sealed and foreign matter such as dust and water is prevented from entering the housing 6. Will be done. In particular, as in the present embodiment, by making the mating surface of the housing split 60 a flat surface parallel to the rotating shaft 2a of the electric motor 2 (without a step), the mating surfaces of the housing split 60 are aligned with each other at the time of assembly. Even if there is some deviation between the mating surfaces, it is difficult for gaps to occur between the mating surfaces, and it is easy to ensure airtightness. As the sealing member, a solid sealing material such as an O-ring, a rubber sheet, a resin sheet, a joint sheet, or a metal gasket, or a liquid sealing member such as a liquid gasket can be adopted.

As shown in FIG. 2, the first motion conversion mechanism 4 has a screw shaft 7 as a rotating member and a nut 8 as a linear motion member. The nut 8 linearly moves in the direction of the axis of rotation as the screw shaft 7 rotates. Thread grooves are formed on the outer peripheral surface of the screw shaft 7 and the inner peripheral surface of the nut 8, respectively, and these screw shafts are directly screwed to form a sliding screw mechanism. As the first motion conversion mechanism 4, a ball screw mechanism in which a plurality of balls are interposed between the screw shaft (rotating member) and the nut (linear motion member) may be used. The screw shaft 7 is rotatably supported with respect to the housing 6 at both ends in the rotation axis direction via a radial bearing 9 and a thrust bearing 10, respectively. Further, the two sets of radial bearings 9 and thrust bearings 10 arranged on one end side and the other end side of the screw shaft 7 are held by a bearing holder 18 assembled to the housing 6, respectively.

The second motion conversion mechanism 5 includes a cylindrical output shaft 14 and a swing member 11 attached to the output shaft 14. The output shaft 14 is rotatably supported by the housing 6 via a radial bearing 15 (see FIG. 1). The swing member 11 is attached to both ends of the output shaft 14 in the axial direction, and is configured to swing (rotatably) integrally with the output shaft 14 around the output shaft 14. Further, the output shaft 14 is provided with a connecting hole 14a in which a plurality of irregularities (splines) are formed on the inner peripheral surface. The connecting hole 14a is a hole for inserting an operation shaft provided in an operation target (not shown). When the operating shaft is inserted into the connecting hole 14a and spline-fitted, the operating shaft is rotatably connected to the output shaft 14. As described above, the output shaft 14 is a member that transmits the driving force of the electric actuator 1 to the outside (operation target) and outputs the driving force. Further, the swing member 11 is provided with a slit-shaped elongated hole 11c that opens at the lower end side shown in FIG. A columnar protrusion 12 protruding from the nut 8 is inserted into the elongated hole 11c. As a result, the nut 8 and the swing member 11 are configured to be interlocked with each other via the protrusion 12. Further, in the present embodiment, the protrusions 12 are provided on the surfaces of the nuts 8 on opposite sides to each other, and the swinging members 11 having the elongated holes 11c are also provided on both sides of the nuts 8 so as to correspond to the protrusions 12. There is.

The speed reducer 3 is arranged between the electric motor 2 and the first motion conversion mechanism 4. In this embodiment, a two-stage planetary speed reducer 20 is used as the speed reducer 3. Specifically, as shown in FIG. 2, the planetary speed reducer 20 includes a first sun gear 21 as a first-stage input rotating body, a plurality of first planetary gears 22 as a first-stage planetary rotating body, and one stage. A first carrier 23 that also serves as an output rotating body for the eyes and an input rotating body for the second stage, a plurality of second planetary gears 24 as the planetary rotating bodies for the second stage, and a second carrier as the output rotating body for the second stage. It includes a carrier 25 and a ring gear 26 that also serves as a first-stage and second-stage track ring.

The first sun gear 21 is attached to the rotating shaft 2a of the electric motor 2 so as to rotate integrally with the rotating shaft 2a. The ring gear 26 is arranged on the outer periphery of the first sun gear 21 and is assembled so as not to rotate with respect to the housing 6. A plurality of first planetary gears 22 are provided in the circumferential direction of the first sun gear 21. Each first planetary gear 22 is interposed between the first sun gear 21 and the ring gear 26, and is arranged so as to mesh with each other. Further, each first planetary gear 22 is rotatably attached to a flange portion 23b protruding in the outer diameter direction from the cylindrical portion 23a of the first carrier 23. A gear portion 23c in which a plurality of teeth are arranged in the circumferential direction is provided on the outer peripheral surface of the cylindrical portion 23a of the first carrier 23. Further, the rotating shaft 2a of the electric motor 2 is inserted into the inner circumference of the cylindrical portion 23a of the first carrier 23 in a relatively rotatable state. A plurality of second planetary gears 24 that mesh with the gear portions 23c of the first carrier 23 and the ring gears 26 are arranged. Each second planetary gear 24 is rotatably attached to a flange portion 25b protruding in the outer diameter direction from the cylindrical portion 25a of the second carrier 25. Further, the second carrier 25 is inserted with one end side of the screw shaft 7. A plurality of irregularities (splines) 25d and 7a extending in the axial direction are formed on the inner peripheral surface of the cylindrical portion 25a of the second carrier 25 and the outer peripheral surface on the one end side of the screw shaft 7, respectively, and these irregularities are formed. By spline fitting the 25d and 7a together, the screw shaft 7 is movable in the axial direction with respect to the second carrier 25 and is integrally rotatably connected in the circumferential direction. Further, on the outer peripheral surface of the cylindrical portion 25a of the second carrier 25, one radial bearing 9 that supports one end side of the screw shaft 7 is arranged.

Here, in the present embodiment, the first carrier 23 also serves as the first-stage output rotating body and the second-stage input rotating body, but functions as the first-stage output rotating body (first planetary gear 22). The flange portion 23b) for holding the above and the portion (cylindrical portion 23a having the gear portion 23c) that functions as the input rotating body of the second stage may be configured as separate bodies. Similarly, the ring gear 26 also has a portion that functions as a first-stage orbital ring (a portion that meshes with the first planetary gear 22) and a portion that functions as a second-stage orbital ring (a portion that meshes with the second planetary gear 24). It may be configured separately.

Subsequently, the operation of the electric actuator according to the present embodiment will be described.

Electric power is supplied from the power source to the electric motor 2 by switching the relay circuit, and when the electric motor 2 rotates in the forward direction or in the reverse direction, the rotational motion is transmitted to the planetary reducer 20 (reducer 3). In the planetary speed reducer 20, the first sun gear 21 rotates integrally with the electric motor 2 (rotating shaft 2a), so that a plurality of first planetary gears 22 meshing with the electric motor 2 start to rotate. Each first planetary gear 22 revolves along the ring gear 26 while rotating, and the revolving motion is output as the rotational motion of the first carrier 23 holding the first planetary gear 22. As a result, the rotational movement of the electric motor 2 is decelerated by one step.

Further, as the first carrier 23 rotates, a plurality of second planetary gears 24 that mesh with the gear portion 23c start to rotate. Each second planetary gear 24 revolves along the ring gear 26 while rotating, and the revolving motion is output as the rotational motion of the second carrier 25 holding the second planetary gear 24. As a result, the rotational motion is further decelerated.

As described above, the rotational motion of the rotary shaft 2a is decelerated and transmitted to the screw shaft 7 via the planetary reducer 20. Therefore, the rotational torque of the screw shaft 7 can be increased, and even a small electric motor 2 can obtain a large rotational torque.

The rotational motion decelerated by the speed reducer 3 is transmitted to the first motion conversion mechanism 4. That is, when the second carrier 25 of the planetary reducer 20 rotates, the screw shaft 7 of the first motion conversion mechanism 4 rotates integrally with the second carrier 25. When the screw shaft 7 rotates, the nut 8 moves linearly with the rotation. The nut 8 advances in the direction of arrow A1 in FIG. 2 when the electric motor 2 rotates in the forward direction, and retracts in the direction of arrow A2 in FIG. 2 when the electric motor 2 rotates in the reverse direction.

Then, as the nut 8 moves forward or backward, the swing member 11 is pushed and moved by the protrusion 12 provided on the nut 8. As a result, the swing member 11 swings in the direction of arrow B1 or arrow B2 in FIG. 2, and the output shaft 14 rotates integrally with the swing member 11, so that the linear motion of the nut 8 is caused by the electric motor 2. It is output as a rotary motion of an axis (output shaft 14) in a direction different from that of the rotary shaft 2a. In the present embodiment, the output shaft 14 is arranged in a direction orthogonal to the rotation shaft 2a of the electric motor 2 (direction orthogonal to the paper surface of FIG. 2). Therefore, the rotary motion of the electric motor 2 is output as a rotary motion of an axis orthogonal to the rotary axis 2a of the electric motor 2.

Next, a detection mechanism for detecting the movement of the nut 8 will be described.

As shown in FIG. 2, the detection mechanism 30 includes a magnet 31 as a detected portion and a magnetic sensor 32 as a detection portion. The magnet 31 is a permanent magnet.

The magnetic sensor 32 is provided on the sensor board 33 fixed to the housing 6, and the wiring 34 is connected to the sensor board 33. In this embodiment, a Hall element is used as the magnetic sensor 32. The magnet 31 is fixed to the lower end surface of the nut 8 as shown in FIG. 1, and linearly moves integrally with the nut 8. The magnetic sensor 32 faces the magnet 31. By providing the side of the magnetic sensor 32 to which the wiring 34 is connected to the housing 6 which is the stationary side, the wiring 34 does not sway or get caught due to the linear movement of the nut 8.

The wiring 34 extending from the sensor board 33 extends to the outside through a through hole provided in the housing 6. Then, the wall surface portion constituting the through hole of the housing 6 and the wiring 34 are sealed with a grommet 35 made of rubber or the like. However, the wiring 34 can be embedded in the housing 6 and connected to the relay circuit in the electric actuator 1.

As shown in FIG. 3, the relay circuit 61, the control unit 62, and the magnetic sensor 32 (sensor board 33) are supplied with electric power from the power supply 63. The magnetic sensor 32 detects the magnet 31 and inputs the detection result to the control unit 62. The control unit 62 includes a CPU and the like. The control unit 62 calculates the rotation angle of the output shaft 14 based on the input signal from the magnetic sensor 32. Using this calculation result, the relay circuit 61 is switched on and off. More specifically, the relay circuit 61 has a forward rotation relay circuit and a reverse rotation relay circuit for rotating the electric motor 2 in the forward or reverse direction, respectively, and based on the input signal from the control unit 62, these circuits Turn either ON or OFF. When any circuit of the relay circuit 61 is turned on, the electric motor 2 is driven and the rotating shaft 2a rotates in the corresponding direction.

As shown in FIG. 4A → FIG. 4B, when the nut 8 moves linearly with the rotation of the screw shaft 7, the magnet 31 also moves integrally with the nut 8. The movement amount of the nut 8 can be calculated by detecting the movement of the magnet 31 by the magnetic sensor 32 facing the magnet 31. Then, the above-mentioned control unit can calculate the rotation angle of the output shaft 14 from the movement amount of the nut 8.

As shown in FIG. 2, the control of the rotation angle of the output shaft 14 is controlled so as to rotate within the range between two points from the position of the rotation limit in the arrow B1 direction to the position of the rotation limit in the arrow B2 direction. ..

In this embodiment, as shown in FIG. 4B, when the output shaft 14 rotates to a position close to the rotation limit in the arrow B2 direction, the magnetic sensor 32 is located near the other end of the magnet 31 (the right end in FIG. 4b). Facing. Further, although not shown, when the output shaft 14 rotates to a position close to the rotation limit in the arrow B1 direction, the magnetic sensor 32 faces a position close to one end (left end in FIG. 4b) of the magnet 31.

FIG. 5 is a diagram showing the relationship between the output voltage of the Hall element and the rotation angle of the output shaft 14. The horizontal axis of FIG. 5 indicates the magnetic flux density B [mT], the vertical axis of the solid line is the output voltage of the Hall element per unit movement amount of the nut 8 (magnet 31), and the vertical axis of the dotted line is the rotation angle of the output shaft 14. Is shown.

As shown by the solid line in FIG. 5, as the magnetic flux density of the magnet 31 increases, the voltage output by the magnetic sensor 32, which is a Hall element, also increases, and the two are in a proportional relationship. Further, the smaller the rotation angle of the output shaft 14, the larger the magnetic flux density of the magnet 31, and the two are in an inversely proportional relationship. From the above, the value of the voltage output by the Hall element and the value of the rotation angle of the output shaft 14 at that time correspond to each other on a one-to-one basis. Therefore, the rotation angle of the output shaft 14 can be calculated by measuring the output voltage of the Hall element.

As described above, by using the detection result of the detection mechanism 30, the rotation angle of the output shaft 14 can be calculated, and the rotation angle of the output shaft 14 can be controlled. That is, the rotation angle of the output shaft 14 can be regulated within the range between the two points from the position of the rotation limit in the arrow B1 direction to the position of the rotation limit in the arrow B2 direction.

As described above, in the present embodiment, it is intended that the operating amount of the output shaft 14 is calculated and the operating range is regulated for the electric actuator 1 having a sufficient configuration if the output shaft 14 is regulated at two positions. It is adopted as a target. That is, in principle, it is not limited to the above two points, but is intentionally adopted with a configuration capable of detecting (calculating) and regulating an arbitrary position between the two points. As a result, as compared with the method of structurally restricting the rotation range of the output shaft 14 by engaging the members at both ends of the movable range as in the above-mentioned Patent Document 1, noise is generated due to the collision between the members. It is possible to prevent wear and tear of members.

In particular, in the present embodiment, in the step of converting the rotational motion of the rotary shaft 2a of the electric motor 2 into the rotary motion of the output shaft 14, the linear motion of the nut 8 on the side closer to the output shaft 14 is detected, so that it is further upstream. Compared with the case where the detection operation is performed in the process of, the rotation angle of the output shaft 14 can be calculated with high accuracy.

Further, when an attempt is made to arrange a detection mechanism that detects the rotation angle from the axial direction with respect to the output shaft 14, the thickness of the electric actuator 1 (the size in the direction perpendicular to the paper surface of FIG. 2) due to the arrangement space of the detection mechanism. There is a risk that the size will increase. However, in the present embodiment, the magnet 31 is used as a detection mechanism for detecting the operation of the nut 8, and the magnet 31 and the magnetic sensor are used in the space on the lower end surface (end surface opposite to the output shaft 14) side of FIG. 2 of the nut 8. By arranging 32, the detection mechanism 30 can be arranged without increasing the size of the electric actuator 1.

Further, since the nut 8 having a movement amount larger than that of the output shaft 14 is detected, the detection operation becomes easy.

Next, an embodiment different from the above embodiment will be sequentially described with respect to the detection mechanism 30 for detecting the movement of the movable member and calculating the rotation angle of the output shaft 14. The description of the configuration common to the above embodiment will be omitted as appropriate. In addition, the symbol is omitted as appropriate for wiring and the like.

As shown in FIG. 6, the detection mechanism 30 of the present embodiment includes a detected gear 36 as a detected unit, a gap sensor 37 as a detected unit, and the like. As the gap sensor 37, for example, an overcurrent sensor, an optical sensor, an ultrasonic sensor, a capacitance sensor, or the like can be used.

The detected gear 36 is provided at the end of the rotating shaft 2a on the opposite side of the speed reducer 3, and rotates integrally with the rotating shaft 2a. Further, the gap sensor 37 is provided at a position facing the detected gear 36, and is fixed to, for example, the housing 6. The gap sensor 37 is connected to the relay circuit in the electric actuator 1 via wiring, receives power supply via the relay circuit, and inputs an output signal to the control unit.

When the detected gear 36 rotates integrally with the rotating shaft 2a, the output signal of the gap sensor 37 changes due to the change in the unevenness of the tooth surface of the detected gear 36 facing the gap sensor 37. By counting the number of changes in the output signal, the rotation angle of the detected gear 36, that is, the rotation shaft 2a can be detected (calculated). Based on this detection result, the control unit can calculate the rotation angle of the output shaft 14. Therefore, the rotation range of the output shaft 14 can be controlled between the above-mentioned two points.

Further, a detection mechanism for detecting the rotation angle of the screw shaft 7 may be provided. For example, as shown in FIG. 7, the detection mechanism 30 of the present embodiment includes an encoder ring 38 as a detected unit, a magnetic sensor 39 as a detection unit, and the like.

The encoder ring 38 is provided on the radial bearing 9 arranged on the other end side of the screw shaft 7. Then, the magnetic sensor 39 faces the encoder ring 38 and is fixed to the housing 6. The encoder ring 38 is provided, for example, on the inner ring of the radial bearing 9, and includes a supported portion and a magnet portion supported by the inner ring. The encoder ring 38 rotates integrally with the inner ring.

A magnetic pole N and a magnetic pole S are magnetized at equal intervals in the circumferential direction of the magnet portion of the encoder ring 38. The encoder ring 38 rotates integrally with the screw shaft 7 and changes the arrangement of the magnetic pole N and the magnetic pole S in the circumferential direction. The magnetic sensor 39 detects a change in the magnetic pole of the encoder ring 38 due to the rotation of the screw shaft 7. Then, the rotation angle of the screw shaft 7 can be calculated from the detection result of the magnetic sensor 39.

Further, as shown in FIG. 8, the detection mechanism 30 may be arranged on the other end side of the screw shaft 7. Specifically, the detection mechanism 30 includes a magnet 40, a magnetic sensor 41, and the like. The magnet 40 is arranged in the recess 7b formed on the other end side of the screw shaft 7, and the magnetic sensor 41 is provided at a position facing the magnet 40.

The magnetic pole N and the magnetic pole S are magnetized at equal intervals in the circumferential direction of the magnet 40. Similar to the embodiment of FIG. 7, the magnet 40 rotates integrally with the screw shaft 7 to change the arrangement of the magnetic pole N and the magnetic pole S in the circumferential direction. The magnetic sensor 41 detects the change in the magnetic pole of the magnet 40 due to the rotation of the screw shaft 7, so that the rotation angle of the screw shaft 7 can be calculated.

In these embodiments of FIGS. 7 and 8, the rotation amount of the screw shaft 7 can be calculated by using the detection result by the magnetic sensor 41, and the rotation angle of the output shaft 14 can be calculated from the rotation amount of the screw shaft 7. Therefore, the rotation range of the output shaft 14 can be controlled between the above-mentioned two points.

Also in the detection mechanism 30 of the embodiment of FIGS. 6 to 8 described above, it is possible to calculate and control the rotation angle of the output shaft 14 without increasing the size of the electric actuator 1 in the thickness direction thereof. Further, since the members do not collide with each other during the detection operation, it is possible to prevent the generation of noise, damage and wear of the members. Further, since the member having a larger movement amount than the output shaft 14 is targeted for detection, the detection becomes easy.

Further, in the above embodiment, the rotation angle of the output shaft 14 is calculated by detecting the operation of the nut 8, the rotation shaft 2a, and the screw shaft 7, which are movable members on the upstream side of the output shaft 14. .. However, a detection mechanism that directly detects the rotational operation of the output shaft 14 may be provided.

For example, as shown in FIG. 9, the detection mechanism 30 of the present embodiment includes a gap sensor 42 as a detection unit, an outer peripheral surface 14b of an output shaft 14 as a detection unit, and the like.

The output shaft 14 has two holes 14b1 and 14b2 that open on the outer peripheral surface 14b side. The holes 14b1 and 14b2 are provided at different positions in the circumferential direction of the output shaft 14. Further, the gap sensor 42 is provided so as to face the outer peripheral surface 14b of the output shaft 14. The gap sensor 42 is connected to the relay circuit in the electric actuator 1 via wiring.

When the output shaft 14 rotates in the arrow B1 direction or the arrow B2 direction due to the rotation of the electric motor 2, the hole portion 14b1 or the hole portion 14b2 faces the gap sensor 42, and the gap sensor 42 changes its detection state. As a result, two points of the output shaft 14 can be detected, and the output shaft 14 can be controlled to rotate within the range D. Further, instead of providing the holes 14b1 and 14b2 on the outer peripheral surface 14b, the outer peripheral surface 14b may be knurled or the tooth surface of the gear may be provided to form irregularities so that the outer peripheral surface 14b can be detected by the gap sensor 42. good.

Further, as shown in FIG. 10, a magnet portion 43 as a detected portion may be provided on the outer peripheral surface side of the output shaft 14, and a magnetic sensor 44 as a detection portion may be provided facing the magnet portion 43. The magnet portion 43 rotates integrally with the output shaft 14. In the magnet portion 43, N poles and S poles are alternately arranged in the circumferential direction of the output shaft 14. When the output shaft 14 rotates, the magnetic pole on the surface of the magnet portion 43 facing the magnetic sensor 44 changes, so that the detection state of the magnetic sensor 44 changes. By detecting this change in the detection state, the rotation angle of the output shaft 14 can be calculated.

As described above, in these embodiments, the output shaft 14 can be directly detected and the rotation angle thereof can be calculated, so that the rotation angle can be calculated with high accuracy. Further, since the operation of the output shaft 14 is detected from its radial direction, the electric actuator 1 does not become large in its thickness direction. Further, since the members do not collide with each other during the detection operation, it is possible to prevent the generation of noise, damage and wear of the members.

Further, a three-phase brushless motor may be adopted as the electric motor 2, and this brushless motor may be used for calculating the rotation angle of the output shaft 14.

Specifically, as shown in FIG. 11, the electric motor 2 rotates integrally with the rotating shaft 2a, and has a magnet 51 having N poles and S poles alternately in the circumferential direction thereof, and a plurality of magnetic sensors 52. It has a U, V, W three-phase coil portion 53 and the like, which are composed of a stator core and windings wound around the stator core. The magnetic sensor 52 is a Hall element or a Hall IC. Further, the detection mechanism 30 is configured by the magnet 51 as the detected unit and the magnetic sensor 52 as the detection unit. The main configurations other than the electric motor 2 are the same as those of the embodiment shown in FIG.

The electric motor 2 switches the energization to each motor unit 53 by detecting the change in the magnetic pole of the magnet 51 that rotates integrally with the rotating shaft 2a by the magnetic sensor 52.

As described above, for the rotation control of the electric motor 2, it is sufficient to monitor the timing of the magnetic pole change detected by the magnetic sensor 52 and detect the rotation position of the rotation shaft 2a. However, in the present embodiment, the control unit counts the number of times the magnetic pole changes and calculates the amount of rotation of the rotating shaft 2a. Thereby, as in the embodiment of FIG. 6, the rotation angle of the output shaft 14 can be calculated, and the rotation angle of the output shaft 14 can be controlled.

As described above, the brushless motor is provided with a rotation detection mechanism for detecting the rotation position of the rotation shaft 2a, specifically, a magnet 51 and a magnetic sensor 52, and the rotation detection mechanism controls energization to the motor unit 53. Has been done. And in this embodiment, this rotation detection mechanism is used as a detection mechanism for detecting the rotation angle of the output shaft 14. Therefore, unlike the above-described embodiment, it is not necessary to separately provide a detection mechanism for making it possible to calculate the rotation angle of the output shaft 14. Therefore, the number of parts of the electric actuator 1 can be reduced, and the size and cost of the electric actuator 1 can be reduced. The rotation detection mechanism provided in the brushless motor is not limited to the above, and may be, for example, a resolver (resolver rotor and resolver stator).

Further, by adopting a breathless motor for the electric motor 2, the life of the electric motor 2 can be extended as compared with the case where a motor with a brush is adopted.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and it goes without saying that various modifications can be made without departing from the gist of the present invention.

As described above, the nut 8, the rotating shaft 2a of the electric motor 2, the screw shaft 7, and the like, which are movable members in the electric actuator 1, are provided with detected portions that move integrally with these movable members. By detecting the amount of movement of the detected unit, the rotation angle of the output shaft 14 can be calculated. Alternatively, by using the output shaft 14 and the member attached to the output shaft 14 as the detected unit, the amount of rotation thereof can be calculated. However, the movable member is not limited to the above as long as it is a movable member in the electric actuator 1 and the rotation amount of the output shaft 14 can be calculated by calculating the operation amount thereof. For example, as a movable member, a detection unit may be provided on the gear in the speed reducer 3, and a detection unit for detecting the detected unit may be provided.

The detection mechanism provided in the electric actuator 1 and its arrangement are not limited to the above combinations. As the detection unit, a contact sensor, a magnetic sensor, an optical sensor, a laser sensor, or the like can be appropriately used.

In the electric actuator 1 of the above embodiment, the axial direction of the output shaft 14 (and the operation axis of the operation target that rotates integrally with the output shaft 14) is orthogonal to the axial direction of the rotary shaft 2a of the electric motor 2. Although some cases have been illustrated, the present invention is not limited to this. For example, the axial direction of the rotating shaft of the electric motor may be parallel to the axial direction of the rotating shaft of the output shaft. In this case, the electric actuator is, for example, a thin motor having an axial direction of the rotation axis in the thickness direction (direction perpendicular to the paper surface of FIG. 2). Then, due to the forward or reverse operation of the rotary shaft of the electric motor, the swing member swings in each direction via a speed reducer or the like composed of gears or the like, and the output shaft rotates forward or reverse. Even in such an electric actuator, a detection mechanism for detecting the amount of movement of the movable member provided in the electric actuator can be provided. As a result, the rotation angle of the output shaft can be regulated within a predetermined range without generating noise, wearing or damaging the members.

In the above embodiment, the electric actuator 1 including the output shaft 14 and the swing member 11 as separate members is used, but the electric actuator 1 of the present invention includes the output shaft and the swing member as the same member. It includes. That is, the electric actuator of the present invention integrally has a portion (swing member) that is pushed and moved by the nut 8 and swings, and a portion (output shaft) in which the operation shaft provided in the operation target is inserted and rotates. It may be provided with a member.

1 Electric actuator 2 Electric motor 2a Rotating shaft 3 Reducer 6 Housing 7 Screw shaft 8 Nut (linear motion member)
9 Radial bearing (bearing)
11 Swing member 14 Output shaft 14b Outer peripheral surface of output shaft 30 Detection mechanism 31 Magnet (detected part)
32 Magnetic sensor (detector)

Claims (7)

Detection of an electric motor, a speed reducer that decelerates and outputs the rotation of the electric motor, a swing member that swings with the rotation of the electric motor, and an output shaft that rotates with the swing of the swing member. It is an electric actuator equipped with a mechanism.
The detection mechanism detects the movement of the movable member in the electric actuator, and the detection mechanism detects the movement of the movable member.
An electric actuator characterized in that the rotation range of the output shaft is restricted to a range between two points from a position on one side to a position on the other side in the rotation direction based on the detection result of the detection mechanism. The electric actuator according to claim 1, further comprising a screw shaft that is rotated by the output of the speed reducer and a linear motion member that linearly moves in the axial direction by the rotation of the screw shaft and swings the swing member. There,
The detection mechanism is an electric actuator including a detection unit and a detected unit provided on the linear motion member and detected by the detection unit. The electric motor includes a rotating shaft and has a rotating shaft.
The electric actuator according to claim 1, wherein the detection mechanism includes a detection unit and a detected unit provided on the rotation shaft and detected by the detection unit. A screw shaft that rotates by the output of the reducer, a bearing that rotatably supports the screw shaft, and a linear motion member that linearly moves in the axial direction by the rotation of the screw shaft and swings the swing member. The electric actuator according to claim 1, further comprising.
The detection mechanism is an electric actuator including a detection unit and a detected unit provided on the bearing and detected by the detection unit. The electric actuator according to claim 1, further comprising a screw shaft that is rotated by the output of the speed reducer and a linear motion member that linearly moves in the axial direction by the rotation of the screw shaft and swings the swing member. There,
The detection mechanism is an electric actuator including a detection unit and a detected unit provided on the screw shaft and detected by the detection unit. The first aspect of the present invention, wherein the detection mechanism includes a detection unit and a member provided on the outer peripheral surface of the output shaft or the outer peripheral surface side of the output shaft, and is detected by the detection unit. Electric actuator. The electric motor is a brushless motor.
The electric actuator according to claim 1, wherein a rotation detection mechanism provided on the brushless motor and detecting a rotation position of the brushless motor is the detection mechanism.

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