JP2017207182A - Electric actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric actuator which is small and has good mountability, which can deal with different stroke amounts according to use at low cost and which is suitable to series manufacture.SOLUTION: An electric actuator 1 includes a motor part A, a motion conversion mechanism part B, an operation part C and a terminal part D. A hollow rotary shaft 26 for supporting a rotor core 24a of the motor part A is rotatably supported by rolling bearings 27, 30. The motion conversion mechanism B is connected to the hollow rotary shaft 26 and includes a ball screw 31, a ball screw nut 32 is arranged inside the hollow rotary shaft 26, and the operation part C is connected to the motion conversion mechanism part B. A boll screw shaft 33 and a whirl-stop guide part N are fitted in a concavo-convex manner. The ball screw shaft is guided with a stroke amount based on the axial direction width of the whirl-stop guide part N, the whirl-stop guide part N is formed by a whirl-stop guide member 10 separately from a casing 20, and a connection structure Q is provided which enables replacement of the whirl-stop member.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electric actuator.

  In recent years, electrification has progressed to save power and reduce fuel consumption of vehicles, etc., for example, a system for operating an automatic transmission, brakes, steering, etc. of an automobile with the power of an electric motor has been developed and put on the market. . As an actuator used for such an application, there is one using a ball screw mechanism in order to convert the rotational motion of an electric motor into linear motion (Patent Document 1).

JP 2014-18007 A

  In Patent Document 1, a ball screw nut and an electric motor rotor are integrated, the electric motor rotor has the function of a ball screw nut, and a part of the rotor is also used as an inner ring of a rolling bearing that supports the rotor. Electric actuators have been proposed. And when using this electric actuator for vehicles, such as a car, from the request | requirement of making mass as small as possible and reducing cost as much as possible, the structure with few parts as much as possible is desirable. In addition, regarding the integration of the rotor (ball screw nut) and the inner ring of the rolling bearing, the inner ring of the rolling bearing and the nut of the ball screw have the same functions required for each material. It can be used.

  However, it has been found that there is little effect obtained by integrating the rotor and ball screw nuts when considering the common use of ball screw nuts in the series of linear actuators due to the development of a variety of parts that share parts. did.

  In addition, when balancing the rotation of the motor, the radial load applied to the rolling bearing that supports the rotor core is about the weight of the rotor core.Therefore, it is not necessary to use a high-strength material for the rolling bearing. It has been found that no heat treatment is required, or that high temperature tempering (tempering) is sufficient.

  Furthermore, in the pursuit of the series of electric actuators, the electric actuator of Patent Document 1 is designed exclusively for each product for applications where the required stroke amount is different, and is a linear actuator with a wide variety of parts that share parts. It became clear that there was a problem in the series. Focusing on this problem, we have reached the point that it is desirable to use a series of electric actuator casings that can accommodate different stroke amounts.

  In view of the above problems, an object of the present invention is to provide an electric actuator that is small in size, has good mountability, can be used at low cost for applications having different required stroke amounts, and is suitable for series production.

  As a result of various studies to achieve the above object, the present inventors have come up with a new idea that the rotation guide member of the ball screw shaft of the electric actuator can be changed according to the stroke amount.

  As a technical means for achieving the above-mentioned object, an electric actuator including a motor unit, a motion conversion mechanism unit, an operation unit, and a terminal unit, wherein a hollow rotary shaft that supports a rotor core of the motor unit is formed by a rolling bearing. The motion conversion mechanism is connected to the hollow rotary shaft and includes a ball screw. A ball screw nut of the ball screw is disposed inside the hollow rotary shaft, and the operation unit is moved to the motion. In the electric actuator connected to the conversion mechanism portion, the ball screw shaft and the non-rotating guide portion are concavo-convexly fitted, and the ball screw shaft is guided by a stroke amount based on the axial width of the non-rotating guide portion. The stop guide portion is formed by a rotation guide member separate from the casing of the electric actuator, The rotating guide member and the end portion of the work portion side, and having a connecting structure that allows replacement of the rotating guide member. With the above configuration, it is possible to realize an electric actuator that is small in size, has good mountability, can be used at low cost for applications with different required stroke amounts, and is suitable for series production.

  Applications that require different stroke amounts by sharing the main body of the electric actuator (motor part A, motion conversion mechanism part B, terminal part D, casing, etc.) by changing the stroke amount of the non-rotating guide member to be replaced. Therefore, an electric actuator suitable for series production can be realized.

  The configuration in which the above-described ball screw shaft and the non-rotating guide portion are concavo-convex-fitted includes a guide groove provided in the inner peripheral portion of the anti-rotation guide member, and an engagement provided in the ball screw shaft fitted in the guide groove. A stop member is preferred. Thereby, while being able to form a rotation prevention guide part by simple structure, the rotation prevention guide member from which stroke amount differs can be manufactured easily.

  By configuring the locking member with a pin provided on the ball screw shaft and a guide collar fitted around the pin, smooth guidance can be achieved with a simple configuration.

  The connection structure of the anti-rotation guide member and the casing has at least one fixing means, and the rotation of the guide groove provided in the anti-rotation guide member is prevented by preventing relative rotation of the anti-rotation guide member with respect to the casing. The accuracy in the phase direction is also good. Further, the assembly and connection workability of the non-rotating guide member is easy.

  By forming the fixing means from a through hole provided in the non-rotating guide member, a key groove provided in the casing, and a pin inserted into the through hole and the key groove, the anti-rotation is prevented. The accuracy in the rotational phase direction of the guide groove provided in the guide member is also good, and the assembly and connection workability of the non-rotating guide member is easy.

  According to the present invention, it is possible to realize an electric actuator that is small in size, has good mountability, can be used at low cost for applications with different required stroke amounts, and is suitable for series production.

It is a longitudinal cross-sectional view of the electric actuator which concerns on one Embodiment of this invention. It is the longitudinal cross-sectional view seen from the EE line of FIG. It is the longitudinal cross-sectional view which took out and expanded the stator and terminal part of the motor of FIG. It is the cross-sectional view seen from the GG line of FIG. It is the cross-sectional view seen from the HH line of FIG. It is a left view of the electric actuator of FIG. It is the longitudinal cross-sectional view of the cover which was seen by the II line | wire of FIG. FIG. 3 is a right side view including a partial cross section taken along the line FF in FIG. 2. It is a front view explaining the assembly | attachment method of a non-rotating guide member. It is a perspective view which shows a rotation prevention guide member. FIG. 10 is a front view for explaining a method of assembling a non-rotating guide member having a stroke amount different from that of the non-rotating guide member of FIG. 9. It is a control block diagram of an electric actuator. It is a control block diagram of an electric actuator.

  An electric actuator according to an embodiment of the present invention will be described with reference to FIGS. First, the overall configuration of the electric actuator of this embodiment will be described.

  FIG. 1 is a longitudinal sectional view showing an assembled state of the electric actuator of the present embodiment, and FIG. 2 is a longitudinal sectional view taken along the line E-E in FIG. As shown in FIGS. 1 and 2, the electric actuator 1 outputs the motion of the motor unit A that generates a driving force, the motion conversion mechanism unit B that converts and outputs the rotation of the motor unit A, and the motion of the motion conversion mechanism unit B. The operation unit C, and the terminal unit D including a power supply circuit, a sensor, and the like are mainly configured.

  The motor part A and the motion conversion mechanism part B are accommodated in the casing 20. The motor part A is configured by a radial gap type motor 25 including a stator 23 fixed to the casing 20 and a rotor 24 disposed so as to face the inner side in the radial direction of the stator 23 with a gap. The stator 23 is configured by attaching a bobbin 23b to the stator core 23a for insulation and winding a coil 23c around the bobbin 23b. The rotor 24 includes a rotor core 24a and a permanent magnet 24b (see FIG. 2) attached to the outer periphery of the rotor core 24a. The rotor 24 is fitted on and fixed to a rotor inner 26 as a hollow rotating shaft.

  The rotor inner 26 has an inner raceway surface 27 a of a rolling bearing 27 formed on the outer periphery of one end (right side in FIGS. 1 and 2), and an outer ring 27 b of the rolling bearing 27 is mounted on the inner peripheral surface of the casing 20. A rolling bearing 30 is mounted between the inner peripheral surface of the other end of the rotor inner 26 (left side in FIGS. 1 and 2) and the outer peripheral surface of the cylindrical portion 29 a of the cover 29. Thereby, the rotor inner 26 is rotatably supported by the rolling bearings 27 and 30 at both ends.

  The motion conversion mechanism B is composed of a ball screw 31. The ball screw 31 mainly includes a ball screw nut 32, a ball screw shaft 33, a large number of balls 34, and a top 35 (see FIG. 2) as a circulation member. . A spiral groove 32 a is formed on the inner peripheral surface of the ball screw nut 32, and a spiral groove 33 a is formed on the outer peripheral surface of the ball screw shaft 33. Balls 34 are loaded between the spiral grooves 32a and 33a, and two tops 35 are incorporated, whereby two rows of balls 34 circulate.

  The ball screw shaft 33 has a hollow hole 33b, and a spring mounting collar 36 is accommodated in the hollow hole 33b. The spring mounting collar 36 is made of a resin material such as PPS, has a circular solid portion 36a at one end (right side in FIG. 1), and a flange-shaped spring receiver at the other end (left side in FIG. 1). It has a part 36b. The spring mounting collar 36 has a recess 36c formed from the inner end of the circular solid portion 36a to the other end.

  The spring mounting collar 36 is inserted into the hollow hole 33b of the ball screw shaft 33, and a pin 37 is fitted through the ball screw shaft 33 and the circular solid portion 36a of the spring mounting collar 36 in the radial direction. And the spring mounting collar 36 are connected and fixed. Guide collars 38 are rotatably fitted on both ends of a pin 37 protruding from the outer peripheral surface of the ball screw shaft 33. The guide collar 38 is made of a resin material such as PPS.

  The rotation prevention guide member 10 is fitted and fixedly connected to the cylindrical portion 20a of the casing 20. A guide groove 10a is provided in the inner periphery of the rotation stop guide member 10, and a guide collar 38 is fitted into the guide groove 10a to prevent the ball screw shaft 33 from rotating. The guide groove 10a provided in the inner peripheral portion of the anti-rotation guide member 10 and the pin 37 and the guide collar 38 as the engaging members provided on the ball screw shaft 33 constitute the anti-rotation guide portion N. Details of the rotation prevention guide portion N will be described later. As a result, when the ball screw nut 32 rotates, the ball screw shaft 33 advances and retreats in the left-right direction in FIGS. An actuator head 39 as an operation portion C is attached to one end portion (right side in FIG. 1) of the ball screw shaft 33. A buffer member 14 made of an elastic member is incorporated between the actuator head 39 and the non-rotating guide member 10. This prevents the ball 34 of the ball screw 31 from being locked even when the ball screw shaft 33 and the spring mounting collar 36 abut against the bottom of the cover 29.

  As shown in FIG. 1, the ball screw nut 32 is press-fitted into the inner peripheral surface of the rotor inner 26 of the motor 25 and is connected so as to be able to transmit torque. Thereby, the rotation of the rotor inner 26 is transmitted to the ball screw nut 32.

  In the present embodiment, the electric actuator 1 having a structure in which the rotor inner 26 directly transmits torque to the ball screw nut 32 is illustrated. However, a speed reducer is connected to the rotor inner 26 so as to be able to transmit torque, and the rotation of the rotor inner 26 is decelerated. It can also be transmitted to the screw nut 32. In this case, rotational torque increases and the motor can be reduced in size.

  As shown in FIG. 1, a thrust receiving ring 46 is attached to the tip of the cylindrical portion 29 a of the cover 29, and between the other end surface (left side in FIG. 1) of the ball screw nut 32 and the thrust receiving ring 46. A thrust needle roller bearing 47 as a thrust bearing is mounted. The thrust needle roller bearing 47 can smoothly support the thrust load when the ball screw nut 32 rotates and the ball screw shaft 33 advances in the right direction in the drawing. Since the thrust needle roller bearing 47 is employed, a large thrust load can be supported with a small mounting space. Further, since the thrust needle roller bearing 47 is disposed within the axial range between the rolling bearings 27 and 30 that support both ends of the rotor inner 26, it is advantageous for moment load. In particular, as in the present embodiment, when the thrust needle roller bearing 47 is arranged at a position close to the center of the axial position of the rolling bearings 27 and 30 that support both ends of the rotor inner 26, the moment load is reduced. Very advantageous.

  A compression coil spring 48 is accommodated in the concave portion 29b on the inner periphery of the cylindrical portion 29a of the cover 29, and both ends of the compression coil spring 48 abut against the thrust needle roller bearing 47 and the spring receiving portion 36b of the spring mounting collar 36, respectively. ing. Due to the spring force of the compression coil spring 48, the ball screw shaft 33 connected to the spring mounting collar 36 is always urged toward the initial position.

  Details of the cover 29 will be described with reference to FIGS. 6 is a left side view of FIG. 1, and FIG. 7 is a vertical cross-sectional view of the cover 29 taken along the line II in FIG. The cover 29 is made of, for example, aluminum, zinc alloy, magnesium alloy, or the like. A through hole (not shown) for inserting the bolt 61 for assembling and fastening the electric actuator 1 and a through hole 62 for attaching the assembled electric actuator 1 to the installation site are provided around the outer periphery of the cover 29 in the radial direction. It has been.

  As shown in FIG. 7, a bearing mounting surface 63 and a fitting surface 64 of the thrust receiving ring 46 are provided on the outer peripheral surface of the cylindrical portion 29a of the cover 29, and a compression coil spring 48 (FIG. 1) is provided on the inner periphery. A recess 29b is formed to accommodate the reference).

  Next, the terminal part D is demonstrated with reference to FIGS. FIG. 3 is an enlarged view of the stator 23 and the terminal portion D of the motor 25 shown in FIG. 4 is a cross-sectional view taken along the line GG in FIG. 1, and FIG. 5 is a cross-sectional view taken along the line H-H in FIG. As shown in FIG. 3, the terminal portion D includes a terminal main body 50, a bus bar 51 and a printed circuit board 52 accommodated in the terminal main body 50. The bus bar 51 and the printed circuit board 52 are screwed to the terminal body 50. As shown in FIGS. 4 and 5, the coil 23c of the stator 23 is once connected to the terminal 51a of the bus bar 51 for each of U, V, and W, and further, as shown in FIG. 2, the terminal 51b of the bus bar 51 is connected. And the terminal block 50a of the terminal body 50 are fastened and connected by screws 70. A terminal 50b extending from the terminal block 50a of the terminal body 50 is connected to a controller (see FIGS. 12 and 13). The terminal 50b is a terminal for power supply. The signal lines are connected by the connector 71 in FIG. As shown in FIGS. 4 and 5, a through hole 68 for assembly fastening and a through hole 69 for attachment are provided on the outer periphery in the radial direction of the terminal body 50.

  The electric actuator 1 of this embodiment is equipped with two types of sensors. These sensors will be described with reference to FIGS. 1, 2, 4 and 5. FIG. One of them is a rotation angle detection sensor 53 used for rotation control of the motor 25. A hall element is suitable as the rotation angle detection sensor 53. As shown in FIGS. 1 and 5, the rotation angle detection sensor 53 is attached to a printed circuit board 52. As shown in FIG. 1, the rotation angle detection sensor 53 includes a pulsar ring 54 attached to the other end (left side in FIG. 1) of the rotor inner 26 of the motor 25 and the electric actuator 1 is assembled. It is arranged so as to face the detection sensor 53 with a gap in the axial direction. The rotation angle detection sensor 53 determines the timing of flowing current in the three phases U, V, and W in order.

  The remaining sensors are stroke detection sensors 55 used for stroke control of the ball screw shaft 33. A stroke detection sensor 55 is also attached to the printed circuit board 52. As shown in FIGS. 2, 4, and 5, a belt-like printed board 56 extending in the axial direction is connected to the printed board 52, and a stroke detection sensor 55 is attached to the printed board 56. The printed circuit board 56 and the stroke detection sensor 55 are disposed in the recess 36 c of the spring mounting collar 36 housed in the hollow hole 33 b of the ball screw shaft 33. A permanent magnet 57 as a target is attached to the inner periphery of the recess 36c of the spring attachment collar 36, and is arranged to face the stroke detection sensor 55 with a gap in the radial direction. Thereby, a signal for stroke control of the ball screw shaft 33 can be taken out.

  In the present embodiment, the electric actuator 1 using the stroke detection sensor 55 is illustrated, but the stroke detection sensor 55 may not be used depending on the application.

  The operational effects of the overall configuration of the electric actuator 1 described above will be described together with reference to FIG. The rotor inner 26 is formed with an inner raceway surface 27a of the rolling bearing 27 at an axial position close to one end of the rotor core 24a at one end (right side in FIG. 1), and at the other end (left side in FIG. 1). A rolling bearing 30 is mounted on the inner peripheral surface at the axial position close to the other end of the rotor core 24a. With such a structure, the rotor inner 26 can be made compact in the axial direction. In addition to this, the structure in which the rolling bearing 27 is arranged inside the axial width of the ball screw nut 32 and the overlapping structure in the radial direction of the rotor inner 26 and the ball screw nut 32 are combined, and the electric motor shown in FIG. The axial dimension L and the radial dimension M of the housing of the actuator 1 can be reduced, and the mountability is improved with compactness.

  The support bearings 27 and 30 of the rotor inner 26 to which the rotor core 24a is attached are only required to support a radial load of the rotor's own weight because the rotation balance of the rotor is taken. The rolling bearing 27 does not need to use a high strength material, and is inexpensive mild steel or the like that is a material of the rotor inner 26, and does not require quenching as a heat treatment. In particular, in the electric actuator 1 of the present embodiment, the reaction force of the linear motion is supported by a dedicated large load capacity thrust needle roller bearing 47. Therefore, since the rolling bearing 27 only needs to have a radial positioning function, the material specifications as described above may be used. Thereby, cost reduction can be achieved.

  Further, since the thrust needle roller bearing 47 is disposed within the axial range between the rolling bearings 27 and 30 that support both ends of the rotor inner 26, it is advantageous for moment load, and the thrust bearing can be reduced in size. . In particular, as in the present embodiment, when the thrust needle roller bearing 47 is arranged at a position close to the center of the axial position of the rolling bearings 27 and 30 that support both ends of the rotor inner 26, the moment load is reduced. This is extremely advantageous and can further reduce the size of the thrust bearing. As a result, the size of the thrust needle roller bearing 47 and the thrust receiving ring 46 can be reduced, which contributes to the compactness of the electric actuator 1 as a whole.

  Since the terminal body 50 is sandwiched between the casing 20 and the cover 29 and the terminal portion is formed in the radial direction, a plurality of casings 20 for accommodating the motor A are stacked in the longitudinal direction, and an electric actuator having a plurality of operation portions C It is also possible.

  The overall configuration of the electric actuator 1 of the present embodiment is as described above. Next, a characteristic configuration will be described with reference to FIGS. 1, 2, and 8 to 11. In summary, the characteristic configuration of the electric actuator 1 of the present embodiment is summarized as follows. The electric actuator casing is shared, the non-rotating guide member is separated from the casing, and the non-rotating guide member having a different stroke amount is replaced with the casing. It is possible. As a result, it is possible to deal with applications with different required stroke amounts at low cost, and it is suitable for series production.

  As shown in FIGS. 1, 2, and 10, the anti-rotation guide member 10 constituting the anti-rotation guide portion N is a separate cylindrical shape from the cylindrical portion 20 a as an end portion on the operation portion C side of the casing 20. It is formed as a part. The anti-rotation guide member 10 is provided with a guide groove 10a that is guided by being fitted with a guide collar 38 on the inner peripheral surface 10b. The guide groove 10 a has an axial length that can secure a stroke amount necessary for the application of the electric actuator 1. An annular groove 12 is formed in the non-rotating guide member 10 so as to be connected to the casing 20, and the annular groove 12 has an inner peripheral surface 12a, an outer peripheral surface 12b, and a bottom surface 12c. An O-ring mounting groove 10c (see FIG. 1) is provided at an end portion of the outer peripheral surface of the non-rotating guide member 10.

  The inner peripheral surface 12a of the annular groove 12 and the outer peripheral surface of the cylindrical portion 20a of the casing 20 are set to a minute fitting clearance in consideration of sealing performance and assembling performance. If necessary, a seal member such as an O-ring may be mounted between the annular groove 12 and the cylindrical portion 20a. The bottom portion 12c of the annular groove 12 abuts the tip of the cylindrical portion 20a of the casing 20, and positions the rotation guide member 10 in the pushing direction. As shown in FIG. 2, the pin 13 is inserted in a state where the rotation guide member 10 is pushed in until the bottom portion 12 c of the annular groove 12 and the tip of the cylindrical portion 20 a of the casing 20 come into contact with each other, and the rotation prevention guide member 10 with respect to the casing 20 is inserted. The relative movement and relative rotation in the axial direction are prevented.

  The connection structure Q between the detent guide member 10 and the casing 20 will be supplemented with reference to FIGS. 8 and 9. FIG. 8 is a right side view including a partial cross-sectional view taken along the line FF in FIG. 2, and FIG. 9 is a front view for explaining a method of assembling the non-rotating guide member. As shown in the drawing, the inner peripheral surface 12 a of the annular groove 12 of the non-rotating guide member 10 is fitted to the outer peripheral surface of the cylindrical portion 20 a of the casing 20 up to a minute fitting clearance. Notch portions 10d are provided at two locations on the outer peripheral surface of the rotation stop guide member 10, and pin holes 10e penetrating through the two notch portions 10d are provided. A key groove 20b having an arc cross section is provided on the outer peripheral surface of the cylindrical portion 20a of the casing 20 corresponding to the pin hole 10e as a through hole.

  Since the pin hole 10e and the key groove 20b are provided in the form as described above, the detent guide member 10 is moved in the direction of the white arrow until the bottom portion 12c of the annular groove 12 and the tip of the cylindrical portion 20a of the casing 20 contact each other. The pin hole 10e and the key groove 20b are aligned with each other pushed in the direction, and the pin (spring pin) 13 is inserted in the direction of the white arrow. Due to such an assembling method, the axial movement and relative rotation of the rotation prevention guide member 10 with respect to the casing 20 can be reliably prevented without rattling, and the rotational phase direction of the guide groove 10b provided in the rotation prevention guide member 10 can be prevented. The accuracy of is also good. Further, the assembly and connection workability of the detent guide member 10 is easy. In the present embodiment, the fixing means includes a pin hole 10e provided in the anti-rotation guide member 10, a key groove 20b provided in the casing 20, and a pin 13 inserted into the pin hole 10e and the key groove 20b. However, the present invention is not limited to this. For example, a key and a retaining ring that prevent relative rotation may be used to appropriately change the structure to prevent relative movement and rotation in the axial direction.

  Next, the case of a non-rotating guide member having a stroke amount different from that of the non-rotating guide member 10 of FIG. 9 will be described with reference to FIG. FIG. 11 is a front view for explaining a method of assembling the non-rotating guide member, as in FIG. 9. The anti-rotation guide member 10 ′ shown in FIG. 11 is the same as the anti-rotation guide member 10 of FIG. 9 except for the stroke amount, and is the same as the anti-rotation guide member 10 of FIG. Reference numeral 10 'is assigned to the guide member, but the same reference numerals are assigned to the parts having the same function, and only the main points will be described. Further, the actuator head 39 ′ shown in FIG. 11 has an axial dimension larger than that of the actuator head 39 shown in FIG. 9 as the stroke amount of the detent guide member 10 ′ increases.

  As shown in FIG. 11, the rotation preventing guide member 10 'has an axial width W2 longer than the axial width W1 of the rotation preventing guide member 10 of FIG. As described above, the stroke amount is determined based on the axial widths W1 and W2 of the non-rotating guide members 10 and 10 '. Further, as described above, the required stroke amount varies depending on the application. On the other hand, the connection structure Q of the anti-rotation guide member 10 ′ is set to have the same shape and dimensions as the anti-rotation guide member 10 of FIG. 9. Therefore, the detent guide member 10 ′ shown in FIG. 11 is also assembled to the casing 20 of the electric actuator 1 by the same assembling method as the detent guide member 10 of FIG. 9. In other words, both the anti-rotation guide member 10 ′ shown in FIG. 11 and the anti-rotation guide member 10 of FIG. 9 can be replaced, that is, have a compatible connection structure Q.

  Therefore, in the electric actuator 1 of the present embodiment, the main body of the electric actuator 1 (the motor part A, the motion conversion mechanism part B, the terminal part D, the casing 20, etc.) is shared, and the anti-rotation guide member 10 having different stroke amounts, 10 'can be replaced by a casing. As a result, it is possible to realize an electric actuator 1 that can be used at a low cost for applications having different required stroke amounts and is suitable for series production.

  Finally, the operation of the electric actuator 1 of the present embodiment will be described with reference to FIGS. 1 and 12. Although illustration is omitted, for example, the operation amount is input to the ECU above the vehicle. From this manipulated variable, the ECU calculates a required position command value. As shown in FIG. 12, the position command value is sent to the controller 81 of the control device 80, and the controller 81 calculates a motor rotation angle control signal necessary for the position command value, and this control signal is sent from the controller 81 to the motor 25. Sent to.

  The rotor inner 26 that is the hollow rotating shaft of the motor 25 that has received the control signal rotates and is transmitted to the motion conversion mechanism B. The ball screw nut 32 connected to the rotor inner 26 rotates, and the ball screw shaft 33 that is prevented from rotating advances forward in the right direction in FIG. 1 and advances to a position based on the control signal of the controller 81, and one end of the ball screw shaft 33 is moved. The actuator head 39 attached to the unit (right side in FIG. 1) operates the control target device (not shown).

  As shown in FIG. 12, the position of the ball screw shaft 33 is sent to the comparison unit 82 of the control device 80, and the difference between the detected value and the position command value is calculated. Based on the value and the signal of the rotation angle sensor 53, a control signal is sent from the controller 81 to the motor 25, and the position of the actuator head 39 is feedback-controlled. For this reason, when the electric actuator 1 of the present embodiment is applied to, for example, shift-by-wire, the shift position can be reliably controlled. The power source is input to the control device 80 from the outside such as a battery provided on the vehicle side (not shown) and used for driving the motor and each sensor.

  FIG. 13 shows a control block diagram when the stroke sensor 55 is not used. In this case, a pressure sensor 83 is provided in a control target device (not shown) in the example of pressure control. When the operation amount is input to the upper ECU of the vehicle, the ECU calculates a required pressure command value. This pressure command value is sent to the controller 81 of the control device 80, and the controller 81 calculates the current value of the motor necessary for the pressure command value and sends it from the controller 81 to the motor 25. As in the case of FIG. 12, the ball screw shaft 33 moves forward in the right direction of FIG. An actuator head 39 attached to one end of the ball screw shaft 33 pressurizes a control target device (not shown).

  The operating pressure of the actuator head 39 is detected by an externally installed pressure sensor 83 and subjected to feedback control. For this reason, when the electric actuator 1 is applied to, for example, brake-by-wire, the hydraulic pressure of the brake can be reliably controlled.

  As described above, the electric actuator 1 according to the present embodiment is small in size, easy to mount, can be applied at low cost to applications with different required stroke amounts, and realizes an electric actuator suitable for series production. Can do.

  The present invention is not limited to the above-described embodiments, and can of course be implemented in various forms without departing from the gist of the present invention. It includes the equivalent meanings recited in the claims and the equivalents recited in the claims, and all modifications within the scope.

DESCRIPTION OF SYMBOLS 1 Electric actuator 10 Anti-rotation guide member 10a Guide groove 12 Annular groove 12a Inner peripheral surface 12b Outer peripheral surface 12c Bottom surface 13 Pin 20 Casing 20a Cylindrical portion 23 Stator 23a Stator core 23b Bobbin 23c Coil 24 Rotor 24a Rotor core 24b Permanent magnet 25 Rotor 26 Motor 26 Hollow rotating shaft)
27 Rolling bearing 27a Inner raceway surface 27b Outer ring 28 Bearing holder 29 Cover 30 Rolling bearing 31 Ball screw 32 Ball screw nut 32a Spiral groove 32b Ball screw nut outer peripheral surface 33 Ball screw shaft 33a Spiral groove 34 Ball 35 Top 36 Spring mounting collar 37 Pin 38 Guide collar 39 Actuator head 47 Thrust needle roller bearing 48 Compression coil spring 50 Terminal body 51 Bus bar 52 Printed circuit board 53 Rotation angle detection sensor 54 Pulsaring 55 Stroke detection sensor 56 Printed circuit board 57 Permanent magnet A Motor part B Motion Conversion mechanism part C Operation part D Terminal part L Axial dimension of casing M Radial dimension of casing N Non-rotating guide part Q Connection structure

Claims (6)

An electric actuator including a motor unit, a motion conversion mechanism unit, an operation unit, and a terminal unit, wherein a hollow rotary shaft that supports a rotor core of the motor unit is rotatably supported by a rolling bearing, and the motion conversion mechanism unit is In the electric actuator connected to the hollow rotary shaft and provided with a ball screw, a ball screw nut of this ball screw is disposed inside the hollow rotary shaft, and the operation unit is connected to the motion conversion mechanism unit,
The ball screw shaft and the non-rotating guide portion are unevenly fitted, and the ball screw shaft is guided by a stroke amount based on the axial width of the non-rotating guide portion,
The non-rotating guide part is formed by a non-rotating guide member separate from the casing of the electric actuator,
An electric actuator characterized in that an end portion of the casing on the operation portion side and the anti-rotation guide member have a connection structure that allows the anti-rotation guide member to be replaced.   The electric actuator according to claim 1, wherein a stroke amount of the detent guide member to be replaced is different.   The structure in which the ball screw shaft and the non-rotating guide portion are concavo-convexly fitted includes a guide groove provided in an inner peripheral portion of the non-rotating guide member, and an engagement provided in the ball screw shaft fitted in the guide groove. The electric actuator according to claim 1, wherein the electric actuator is a stop member.   The electric actuator according to claim 3, wherein the locking member includes a pin provided on the ball screw shaft and a guide collar fitted on the pin.   The connection structure of the non-rotating guide member and the casing has at least one fixing means, and the relative rotation of the non-rotating guide member with respect to the casing is prevented. Electric actuator.   6. The fixing device according to claim 5, wherein the fixing means includes a through hole provided in the detent guide member, a key groove provided in the casing, and a pin inserted into the through hole and the key groove. The electric actuator as described.

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