JP7270426B2 - electric actuator - Google Patents

Description

The present invention relates to an electric actuator.

As an electric actuator capable of changing the rotational phase difference between the input side to which driving force is input from the outside and the output side to output the input driving force, for example, an intake valve and an exhaust valve of an automobile engine. is known to be used in a variable valve timing device that changes the opening/closing timing of one or both of the valves.

For example, Patent Literature 1 discloses an electric actuator provided with a differential gear consisting of a cycloid speed reducer. This electric actuator includes a drive rotor (input rotor) having a sprocket driven by an engine, a driven rotor (output rotor) driven by the drive rotor, and a rotor between the drive rotor and the driven rotor. and an electric motor having a rotor for driving the planetary rotor. The cycloid reducer includes a first external toothed portion formed on the drive rotor, a first internal toothed portion and a second internal toothed portion formed on the inner peripheral surface of the planetary rotor, and a driven rotor formed on the driven rotor. and a second external tooth.

The driven rotor includes a main body having a second external tooth, a camshaft connected to the main body, and a center bolt connecting the main body and the camshaft. The center bolt connects the main body and the camshaft so that they rotate coaxially.

In the electric actuator configured as described above, when the driving force from the engine is transmitted to the sprocket of the drive rotor, the camshaft of the driven rotor rotates in synchronization with the sprocket. In this case, each speed reducer is not driven by an electric motor, and the driving rotor and the planetary rotor, and the planetary rotor and the driven rotor rotate while maintaining mutual engagement.

After that, when the engine shifts to a low speed range such as idling, and the camshaft drives the engine valves, the electric motor rotor is rotated relatively slower or faster than the sprocket rotation speed by electronic control. Let In this case, the electric actuator rotates and eccentrically moves the planetary rotor of the cycloid reducer via the rotor, thereby changing the rotational phase difference of the driven rotor with respect to the drive rotor, thereby adjusting the valve opening/closing timing. adjust.

JP 2018-194151 A

In the above-described conventional electric actuator, when the rotor of the electric motor rotates to change the rotational phase difference of the driven rotor with respect to the drive rotor, the center bolt that connects the main body of the driven rotor and the camshaft is attached to the center bolt. A force can act to loosen the bolt. If the center bolt is loosened, there is a risk that the power given from the electric motor will not be accurately transmitted to the camshaft.

The present invention has been made in view of the above circumstances, and a technical object thereof is to reliably transmit power in a cycloid speed reducer.

The present invention is intended to solve the above-described problems, and includes a drive rotor, a driven rotor driven by the drive rotor, and a cycloid disposed between the drive rotor and the driven rotor. In an electric actuator comprising a differential having a speed reducer and an electric motor for driving the differential, the driven rotating body includes a main body, a shaft connected to the main body, and the main body and the shaft. and a positional deviation prevention portion that prevents relative positional deviation in the circumferential direction of the.

According to this configuration, when the differential gear is driven by the electric motor, the cycloid reducer of the differential mechanism is prevented by preventing relative positional displacement in the circumferential direction between the main body and the shaft by the positional displacement prevention portion. The power from the can be reliably transmitted to the driven rotating body.

The positional deviation prevention part includes a first hole formed in the main body, a second hole formed in the end surface of the shaft, and a connection inserted into the first hole and the second hole. A pin and a may be provided.

The positional deviation prevention portion may include a key groove formed in one of the main body and the shaft, and a key formed in the other.

The main body is configured in a cylindrical shape into which the shaft can be inserted, and the positional deviation prevention portion is formed on a first plane formed on the inner peripheral surface of the main body and on the outer peripheral surface of the shaft. and a second plane in contact with the first plane.

In the electric actuator described above, the electric motor may include an annular rotor, and the positional deviation prevention section may be arranged inside the rotor. According to such a configuration, since the positional deviation prevention portion is arranged so as to overlap the rotor in the axial direction, it is possible to prevent an increase in the axial dimension of the electric actuator.

An electric actuator according to the present invention includes a sprocket provided on the drive rotating body and a cam provided on the shaft, and is a variable valve that changes the opening/closing timing of a valve by changing the rotational phase difference of the shaft with respect to the sprocket. Applicable to timing devices.

ADVANTAGE OF THE INVENTION According to this invention, power transmission of a cycloid reduction gear can be reliably performed.

1 is a cross-sectional view of an electric actuator according to a first embodiment; FIG. 1 is an exploded perspective view of an electric actuator; FIG. 1 is a perspective view of an electric actuator; FIG. It is a perspective view of a camshaft. FIG. 2 is a cross-sectional view taken along line AA of FIG. 1; FIG. 2 is a cross-sectional view taken along line BB of FIG. 1; FIG. 4 is a cross-sectional view of an electric actuator according to a second embodiment; 1 is a perspective view of an electric actuator; FIG. It is a perspective view of a camshaft. FIG. 10 is a cross-sectional view of an electric actuator according to a third embodiment; 1 is a perspective view of an electric actuator; FIG. It is a perspective view of a camshaft.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments for carrying out the present invention will be described based on the accompanying drawings. In addition, in each drawing for explaining the present invention, constituent elements such as members and constituent parts having the same function or shape are given the same reference numerals as much as possible, and once explained, the explanation will be repeated. omitted.

1 to 6 show a first embodiment of an electric actuator according to the invention. FIG. 1 is a longitudinal sectional view of an electric actuator, and FIG. 2 is an exploded perspective view of the electric actuator. FIG. 3 is a perspective view of the electric actuator with the main body of the driven rotor removed, and FIG. 4 is a perspective view of the camshaft in the driven rotor. The electric actuator according to this embodiment is used, for example, as a variable valve timing device for an engine (driving source), but is not limited to this application.

As shown in FIGS. 1 and 2, the electric actuator 1 includes a drive rotor 2, a driven rotor 3, an electric motor 4, a differential gear 5, and a casing 6 housing them as main components. Prepare as

The drive rotator 2 has a generally cylindrical shape with both ends in the axial direction open, and has a main body 21 and a sprocket 22 that serves as an input portion for driving force from the engine. The main body 21 and the sprocket 22 are coaxially arranged with the rotation axis O as the center. Therefore, the main body 21 and the sprocket 22 are integrally rotated around the rotation axis O by the driving force from the engine.

The main body 21 includes a first tubular portion 21 a provided with the sprocket 22 , a second tubular portion 21 b supported by the casing 6 , and a third tubular portion 21 c functioning as part of the differential gear 5 . The sprocket 22 is provided to the first tubular portion 21a of the main body 21 so as to be capable of transmitting torque, and is rotationally driven by the driving force transmitted from the engine via the chain.

The driven rotating body 3 is a member that outputs the driving force transmitted from the driving rotating body 2, and includes a main body 31, a camshaft 32, a center bolt 33, and a positional deviation prevention portion .

The main body 31 has a cylindrical shape with both ends in the axial direction open, and has a shaft accommodating portion 35 for accommodating the camshaft 32 at one end thereof. The shaft accommodating portion 35 is configured in a cylindrical shape and has a contact surface 36 that can come into contact with the camshaft 32 in the axial direction.

Camshaft 32 includes one or more cams (not shown) and is configured to drive at least one of the intake and exhaust valves of the engine. As shown in FIGS. 1, 3 and 4, the camshaft 32 has an end face 37 that contacts the contact face 36 of the shaft receiving portion 35 of the main body 31 and a threaded hole 38 formed in the end face 37 .

The main body 31 and the camshaft 32 are connected to each other by inserting the end of the camshaft 32 into the shaft accommodating portion 35 of the main body 31 and screwing the shaft of the center bolt 33 inserted into the main body 31 into the threaded hole 38 . ing. By this connection, the main body 31 and the camshaft 32 are arranged coaxially on the rotation axis O and rotate about the rotation axis O together.

The positional deviation prevention portion 34 is arranged between the main body 31 and the camshaft 32 and inside the rotor 42 (rotor core 42a). The positional deviation prevention portion 34 is composed of a connecting pin 39 , a first hole portion 31 a formed in the main body 31 , and a second hole portion 32 a formed in the camshaft 32 .

The connecting pin 39 is configured in the shape of a round bar, and has one end inserted into the first hole 31a and the other end inserted into the second hole 32a. The first hole portion 31 a is formed in the contact surface 36 of the shaft housing portion 35 of the main body 31 . The first hole portion 31a is a hole formed parallel to the axis (rotational axis O) of the main body 31 and having a cylindrical inner peripheral surface. The second hole portion 32a is formed in an end face 37 of the camshaft 32. As shown in FIG. The second hole portion 32a is a hole formed parallel to the axis (rotational axis O) of the camshaft 32 and having a cylindrical inner peripheral surface.

The sum of the depth dimension of the first hole portion 31 a and the depth dimension of the second hole portion 32 a is set larger than the length dimension of the connecting pin 39 . With this configuration, when the connecting pin 39 is inserted into the first hole portion 31a and the second hole portion 32a, and the main body 31 and the camshaft 32 are connected by the center bolt 33, the contact surface 36 of the shaft accommodating portion 35 and The end face of the camshaft 32 contacts.

By inserting the connecting pin 39 into the first hole portion 31a and the second hole portion 32a, the positional deviation prevention portion 34 prevents relative positional deviation between the main body 31 and the camshaft 32 in the circumferential direction (rotational direction). can be prevented. As a result, loosening of the center bolt 33 can be prevented, and torque transmission loss can be reliably prevented. Therefore, the reliability of the electric actuator 1 can be improved.

A bearing 8 is arranged between the outer peripheral surface of the camshaft 32 and the inner peripheral surface of the first cylindrical portion 21 a of the main body 21 related to the drive rotor 2 . A bearing 9 is arranged between the casing 6 and the outer peripheral surface of the second cylindrical portion 21 b of the main body 21 relating to the drive rotor 2 . These bearings 8 and 9 allow relative rotation between the drive rotor 2 and the driven rotor 3 . The bearings 8 and 9 are configured by rolling bearings, but are not limited to this, and can be configured by sliding bearings or other bearings.

For the convenience of assembly, the casing 6 is divided into a bottomed cylindrical casing main body 6a and a lid portion 6b. The casing main body 6a and the lid portion 6b are integrated using fastening means such as bolts. The lid portion 6b has a tubular protrusion for drawing out a power supply line for supplying power to the electric motor 4 and a signal line connected to a rotation speed detection sensor (not shown) for detecting the rotation speed of the electric motor 4. 6c and 6d (see FIG. 2) are provided. A bearing 13 is arranged between the inner peripheral surface of the lid portion 6 b of the casing 6 and the outer peripheral surface of the main body 31 of the driven rotating body 3 .

The electric motor 4 is a radial gap type motor having a stator 41 fixed to the casing body 6a and a rotor 42 arranged radially inward of the stator 41 so as to face each other with a gap. The stator 41 is composed of a stator core 41a made of a plurality of magnetic steel sheets laminated in the axial direction, a bobbin 41b made of an insulating material attached to the stator core 41a, and a stator coil 41c wound around the bobbin 41b. The rotor 42 is composed of an annular or cylindrical rotor core (rotor inner) 42a and a plurality of magnets 42b attached to the rotor core 42a. The electric motor 4 rotates the rotor 42 about the rotation axis O by the excitation force acting between the stator 41 and the rotor 42 .

The differential gear 5 includes a main body 21 of the drive rotor 2, a main body 31 of the driven rotor 3, an eccentric member 51 that rotates integrally with the rotor 42, and planetary rotors 52 arranged on the inner periphery of the eccentric member 51. , and a first bearing 53 and a second bearing 54 arranged between the eccentric member 51 and the planetary rotor 52 as main components.

The eccentric member 51 is configured in a cylindrical shape with both axial ends open, and includes a large-diameter cylindrical portion 51a, a medium-diameter cylindrical portion 51b configured to have a smaller diameter than the large-diameter cylindrical portion 51a, and a medium-diameter cylindrical portion 51b. It integrally has a small-diameter cylindrical portion 51c formed to have a smaller diameter.

The large-diameter tubular portion 51a protrudes axially from the medium-diameter tubular portion 51b so as not to overlap the rotor core 42a. The large-diameter cylindrical portion 51a is rotatably supported by the casing main body 6a of the casing 6 via the bearing 17. As shown in FIG. The medium-diameter cylindrical portion 51b is fixed to the inner circumference of the rotor core 42a so as to overlap the rotor core 42a in the axial direction. The small-diameter tubular portion 51c protrudes axially (opposite to the large-diameter tubular portion 51a) from the medium-diameter tubular portion 51b so as not to overlap the rotor core 42a. The small-diameter cylindrical portion 51c is rotatably supported by the lid portion 6b of the casing 6 via the bearing 18. As shown in FIG.

The outer peripheral surface of the large-diameter tubular portion 51a, the outer peripheral surface of the medium-diameter tubular portion 51b, and the outer peripheral surface of the small-diameter tubular portion 51c are cylindrical surfaces formed coaxially with the rotation axis O. An eccentric inner peripheral surface 51 a 1 on a cylindrical surface eccentric with respect to the rotation axis O is formed on the inner peripheral surface of the large-diameter cylindrical portion 51 a of the eccentric member 51 . In addition, an eccentric inner peripheral surface 51b1 in the shape of a cylindrical surface eccentric with respect to the rotation axis O is formed on the inner peripheral surface of the medium-diameter tubular portion 51b of the eccentric member 51 . The large-diameter tubular portion 51a and the medium-diameter tubular portion 51b of the eccentric member 51 have a thick portion and a thin portion due to the relationship between the outer peripheral surface and the eccentric inner peripheral surfaces 51a1 and 51b1.

The planetary rotor 52 has a cylindrical shape with both axial ends open, and includes a large-diameter tubular portion 52a and a small-diameter tubular portion 52b. A first inner toothed portion 55 is formed on the inner periphery of the large diameter cylindrical portion 52a, and a second inner toothed portion 56 is formed on the inner periphery of the small diameter cylindrical portion 52b. Each of the first inner toothed portion 55 and the second inner toothed portion 56 is composed of a plurality of teeth whose cross section in the radial direction draws a curved line (for example, a trocolloidal curved line). The first inner toothed portion 55 and the second inner toothed portion 56 are formed at axially offset positions. The pitch circle diameter of the second internal tooth portion 56 is smaller than the pitch circle diameter of the first internal tooth portion 55 . Further, the number of teeth of the second internal tooth portion 56 is smaller than the number of teeth of the first internal tooth portion 55 .

An end portion 56a of the second internal tooth portion 56 on the side of the first internal tooth portion 55 in the face width direction is formed so as to overlap the outer peripheral surface of the large-diameter cylindrical portion 52a of the planetary rotor 52 in the axial direction. In other words, a portion (end portion 56a) of the second internal tooth portion 56 is formed so as to overlap the second bearing 54 in the axial direction (face width direction).

A first external toothed portion 57 that meshes with the first internal toothed portion 55 is formed on the outer peripheral surface of the third cylindrical portion 21 c of the main body 21 related to the drive rotor 2 . A second external toothed portion 58 that meshes with the second internal toothed portion 56 is formed on the outer peripheral surface of the main body 31 related to the driven rotating body 3 . Each of the first external tooth portion 57 and the second external tooth portion 58 is formed of a plurality of teeth having a radial cross-section that draws a curve (for example, a trochoidal curve). The pitch circle diameter of the second external tooth portion 58 is smaller than the pitch circle diameter of the first external tooth portion 57 , and the number of teeth of the second external tooth portion 58 is smaller than the number of teeth of the first external tooth portion 57 .

One end portion 58a in the face width direction of the second external tooth portion 58 is arranged so as to overlap the outer peripheral surface of the large-diameter cylindrical portion 52a of the planetary rotor 52 in the axial direction. In other words, a portion (end portion 58a) of the second external tooth portion 58 is formed so as to overlap the second bearing 54 in the axial direction (face width direction).

The number of teeth of the first external toothing 57 is less than the number of teeth of the first internal toothing 55 that mesh with each other, preferably one less. Similarly, the number of teeth of the second external toothing 58 is also less than the number of teeth of the second internal toothing 56 that mesh with each other, preferably one less. As an example, in this embodiment, the number of teeth of the first internal tooth portion 55 is 24, the number of teeth of the second internal tooth portion 56 is 20, the number of teeth of the first external tooth portion 57 is 23, and the number of teeth of the second external tooth portion 57 is 23. The tooth portion 58 has 19 teeth.

The first internal toothed portion 55 and the first external toothed portion 57 that mesh with each other constitute the first speed reducer 5a, and the second internal toothed portion 56 and the second external toothed portion 58 constitute the second speed reducer 5b. Both the first reduction gear 5a and the second reduction gear 5b are called cycloidal reduction gears. The reduction ratios of the two reduction gears 5a and 5b are different, and in this embodiment, the reduction ratio of the first reduction gear 5a is made larger than the reduction ratio of the second reduction gear 5b. By making the reduction ratios of the two reduction gears 5 a and 5 b different in this way, it is possible to change (differentially) the rotation of the camshaft 32 according to the operating state of the electric motor 4 .

The first bearing 53 is arranged between the eccentric inner peripheral surface 51 b 1 of the eccentric member 51 and the outer peripheral surface of the small-diameter cylindrical portion 52 b of the planetary rotor 52 . Therefore, the center (P) of the outer peripheral surface and the inner peripheral surface of the planetary rotor 52 is located eccentrically with respect to the rotation axis O. The planetary rotor 52 is supported by the first bearing 53 so as to be rotatable relative to the eccentric member 51 . The first bearing 53 is, for example, a needle roller bearing having an outer ring 53a and rolling elements 53b (needle rollers). The outer ring 53 a is fixed to the eccentric inner peripheral surface 51 b 1 of the medium-diameter cylindrical portion 51 b of the eccentric member 51 . The rolling element 53b is in contact with the outer peripheral surface (rolling surface) of the small-diameter cylindrical portion 51c of the planetary rotor 52 .

The second bearing 54 is axially displaced from the first bearing 53 so as not to overlap the inner circumference of the rotor core 42 a of the electric motor 4 . Specifically, the second bearing 54 is arranged between the large-diameter tubular portion 52 a of the planetary rotor 52 and the eccentric inner peripheral surface 51 a 1 of the large-diameter tubular portion 51 a related to the eccentric member 51 .

The second bearing 54 is a deep groove ball bearing having an outer ring 54a, an inner ring 54b, and rolling elements 54c (balls). The outer ring 54 a of the second bearing 54 is fixed (press-fitted) to the eccentric inner peripheral surface 51 a 1 of the large-diameter tubular portion 51 a of the eccentric member 51 . The inner ring 54 b of the second bearing 54 is fixed (press-fitted) to the outer peripheral surface of the large-diameter cylindrical portion 52 a of the planetary rotor 52 .

The second bearing 54 is arranged across the reduction gears 5a and 5b so as to support both the first reduction gear 5a and the second reduction gear 5b. That is, the second bearing 54 is formed between the eccentric member 51 and the planetary rotor 52 so as to overlap a part of the first reduction gear 5a in the axial direction and overlap a part of the second reduction gear 5b in the axial direction. placed in between.

FIG. 5 is a cross-sectional view cut along the first reduction gear 5a (cross-sectional view taken along the line AA in FIG. 1), and FIG. arrow view).

As shown in FIG. 5, the center P of the first inner toothed portion 55 is radially eccentric with respect to the rotation axis O by a distance E. As shown in FIG. Therefore, the first inner toothed portion 55 and the first outer toothed portion 57 are meshed with each other in a partial region in the circumferential direction, and are not meshed with each other in a region on the opposite side in the radial direction. In addition, as shown in FIG. 6, the center P of the second inner toothed portion 56 is also eccentric to the rotation axis O by a distance E in the radial direction. , are meshed with each other in some circumferential regions, and are not meshed with each other in a region on the opposite side in the radial direction. 5 and 6, the directions of the arrows are different from each other, so the eccentric directions of the first inner toothed portion 55 and the second inner toothed portion 56 are shown in opposite left and right directions in each figure. However, the first inner toothed portion 55 and the second inner toothed portion 56 are eccentric by the same distance E in the same direction.

Here, if i is the speed reduction ratio of the differential gear 5, nm is the motor rotation speed, and ns is the rotation speed of the sprocket 22, the output rotation phase angle difference is (nm-ns)/i.

Further, when the reduction ratio of the first reduction gear 5a is i1 and the reduction ratio of the second reduction gear 5b is i2, the reduction ratio of the differential gear 5 according to the present embodiment is obtained by the following equation 1.

Reduction ratio=i1×i2/|i1-i2| Expression 1

For example, when the reduction ratio (i1) of the first reduction gear 5a is 24/23 and the reduction ratio (i2) of the second reduction gear 5b is 20/19, the reduction ratio is 120 from the above equation (1). Thus, in the differential gear 5 according to the present embodiment, it is possible to obtain high torque with a large reduction ratio.

In the electric actuator 1 of the present embodiment, since the drive rotor 2 and the driven rotor 3 are arranged on the inner diameter side of the planetary rotor 52, a hollow motor is adopted as the electric motor 4 for driving the planetary rotor 52. A layout is adopted in which this hollow motor is arranged on the outer diameter side of the planetary rotor 52 . Therefore, the space efficiency is improved, and there is an advantage that the electric actuator 1 can be made compact (especially, the size in the axial direction can be made compact).

Next, the operation of the electric actuator according to this embodiment will be described with reference to FIGS. 1 to 6. FIG.

During operation of the engine, the drive rotor 2 is rotated by the driving force from the engine transmitted to the sprocket 22 .

When the electric motor 4 is not energized and there is no input from the electric motor 4 to the differential gear 5, the rotation of the driving rotor 2 is transmitted to the driven rotor 3 via the planetary rotor 52, causing the driven rotor 3 to rotate. rotates integrally with the drive rotor 2 . That is, the driving rotor 2 and the planetary rotor 52 rotate integrally while maintaining this meshing state due to torque transmission at the meshing portion between the first internal toothed portion 55 and the first external toothed portion 57 . Similarly, the planetary rotating body 52 and the driven rotating body 3 also rotate integrally while maintaining the meshing positions of the second internal toothed portion 56 and the second external toothed portion 58 . Therefore, the drive rotor 2 and the driven rotor 3 rotate while maintaining the same rotational phase.

After that, for example, when the engine shifts to a low speed range such as idling, the electric motor 4 is energized by known means such as electronic control, and the rotor 42 is rotated relatively slower than the sprocket 22. Or rotate faster. When the electric motor 4 is operated, the eccentric member 51 coupled to the rotor core 42a of the rotor 42 rotates about the rotation axis O together. Along with this, the pressing force due to the rotation of the eccentric member 51 having the thin-walled portion and the thick-walled portion acts on the planetary rotor 52 via the first bearing 53 . Due to this pressing force, a component of force in the circumferential direction is generated at the meshing portion between the first inner toothed portion 55 and the first outer toothed portion 57 , so that the planetary rotor 52 makes an eccentric rotational motion relative to the drive rotor 2 . I do. That is, the planetary rotor 52 revolves around the rotation axis O and rotates around the center P of the first inner toothed portion 55 and the second inner toothed portion 56 . At this time, every time the planetary rotor 52 revolves once, the engagement position between the first inner toothed portion 55 and the first outer toothed portion 57 shifts in the circumferential direction by one tooth, so the planetary rotor 52 is decelerated. It rotates (rotates).

Further, since the planetary rotor 52 performs the above-described eccentric rotational motion, the engagement portion between the second internal tooth portion 56 and the second external tooth portion 58 is increased by one tooth for each revolution of the planetary rotor 52. It shifts in the circumferential direction. As a result, the driven rotor 3 rotates while being decelerated with respect to the planetary rotor 52 . By driving the planetary rotor 52 with the electric motor 4 in this manner, the driving force from the electric motor 4 is superimposed on the driving force from the sprocket 22 , and the rotation of the driven rotor 3 is the same as the driving force from the electric motor 4 . It becomes a differential state under the influence of force. Therefore, it is possible to change the relative rotational phase difference of the driven rotor 3 with respect to the drive rotor 2 in forward and reverse directions, and change the opening/closing timing of the valve by the cam of the camshaft 32 in the advance direction or in the retard direction. can do. Even when the opening/closing timing of the valve is changed in the advancing direction or the retarding direction in this manner, the positional displacement preventing portion 34 prevents the main body 31 of the driven rotor 3 and the camshaft 32 from being displaced in the circumferential direction. be done.

By changing the opening/closing timing of the valve as described above, it is possible to stabilize the rotation of the engine during idling and improve fuel efficiency. Further, when the operation of the engine shifts from the idling state to normal operation, for example, when it shifts to high-speed rotation, by increasing the speed difference of the relative rotation of the electric motor 4 with respect to the sprocket 22, the camshaft 32 with respect to the sprocket 22 can be changed to a rotation phase difference suitable for high rotation, and it is possible to increase the output of the engine.

7 to 9 show a second embodiment of the electric actuator according to the invention. 7 is a longitudinal sectional view of an electric actuator, FIG. 8 is a perspective view of the electric actuator, and FIG. 9 is a perspective view of a camshaft.

In the electric actuator 1 according to the present embodiment, the displacement prevention portion 34 provided on the driven rotating body 3 and the camshaft 32 is composed of a key 31b formed on the main body 31 and a key groove formed on the outer peripheral surface of the camshaft 32. 32b.

The key 31b is a protrusion that protrudes radially inward from the inner peripheral surface of the shaft accommodating portion 35 of the main body 31 . The key groove 32 b is formed in a range from one end (end face 37 ) of the camshaft 32 to the middle part of the outer peripheral surface of the camshaft 32 .

When the main body 31 and the camshaft 32 are connected to each other by the center bolt 33, the key 31b and the key groove 32b of the displacement prevention portion 34 are fitted to each other, so that the main body 31 and the camshaft 32 are displaced in the circumferential direction. is prevented. In FIG. 8, the entire body 31 is omitted and only the key 31b portion is shown in order to show the fitted state of the key 31b and the key groove 32b.

10 to 12 show a third embodiment of the electric actuator according to the invention. 10 is a longitudinal sectional view of an electric actuator, FIG. 11 is a perspective view of the electric actuator, and FIG. 12 is a perspective view of a camshaft.

In the electric actuator 1 according to this embodiment, the misalignment prevention portion 34 includes a first flat surface 31 c formed on the inner peripheral surface of the shaft housing portion 35 of the main body 31 and a second flat surface 31 c formed on the outer peripheral surface of the camshaft 32 . and a plane 32c. The first plane 31c and the second plane 32c are configured in a so-called D-cut shape.

When the main body 31 and the camshaft 32 are connected by the center bolt 33, the contact between the first flat surface 31c and the second flat surface 32c of the misalignment prevention portion 34 causes the main body 31 and the camshaft 32 to move in the circumferential direction. Misalignment is prevented. In FIG. 11, in order to show the state of contact between the first plane 31c and the second plane 32c, the display of the entire main body 31 is omitted and only the first plane 31c is shown.

In addition, the present invention is not limited to the configuration of the above-described embodiment, nor is it limited to the above-described effects. Various modifications can be made to the present invention without departing from the gist of the present invention.

In the above-described first embodiment, the misalignment prevention portion 34 having one connecting pin 39 was illustrated, but the present invention is not limited to this configuration. The misalignment prevention portion 34 may include a plurality of connecting pins 39 and a plurality of first hole portions 31a and second hole portions 32a.

In the above-described second embodiment, the displacement prevention portion 34 configured by the key 31b formed on the main body 31 and the key groove 32b formed on the camshaft 32 was exemplified, but the present invention is limited to this configuration. not. For example, the positional deviation prevention portion 34 may be configured by a key groove formed in the main body 31 and a key formed in the camshaft 32 . Moreover, the number of the key 31b and the keyway 32b may not be one, and may be plural. The positional deviation prevention portion 34 may be configured by serration fitting.

1 electric actuator 2 drive rotor 3 driven rotor 4 electric motor 5 differential gear 21 sprocket 31 main body of driven rotor 31a first hole 31b key 31c first plane 32 camshaft 32a second hole 32b keyway 32c Two planes 34 Positional deviation prevention portion 42 Rotor

Claims (5)

a differential gear comprising a drive rotor, a driven rotor driven by the drive rotor, a cycloid reducer arranged between the drive rotor and the driven rotor, and driving the differential gear In an electric actuator comprising an electric motor that
The driven rotating body includes a main body, a shaft connected to the main body, and a positional deviation prevention portion that prevents relative positional deviation between the main body and the shaft in the circumferential direction,
The electric motor comprises an annular rotor,
The differential gear is formed between a tubular eccentric member that rotates integrally with the rotor, a planetary rotor arranged on the inner periphery of the eccentric member, and the planetary rotor and the drive rotor. and a second reduction gear formed between the planetary rotor and the driven rotor,
the first speed reducer includes a first internal tooth portion formed on the planetary rotor and a first external tooth portion formed on the drive rotor;
The second speed reducer includes a second internal tooth portion formed on the planetary rotor and a second external tooth portion formed on the driven rotor,
The electric actuator according to claim 1, wherein the positional deviation prevention portion is arranged inside the rotor so as to overlap the rotor in the axial direction of the shaft. The positional deviation prevention part includes a first hole formed in the main body, a second hole formed in the end surface of the shaft, and a connection inserted into the first hole and the second hole. The electric actuator according to claim 1, comprising a pin. 2. The electric actuator according to claim 1, wherein the positional deviation prevention portion includes a key groove formed on one of the main body and the shaft, and a key formed on the other. The main body is configured in a tubular shape into which the shaft can be inserted,
2. The method according to claim 1, wherein the positional deviation prevention portion includes a first plane formed on the inner peripheral surface of the main body and a second plane formed on the outer peripheral surface of the shaft and in contact with the first plane. Electric actuator as described. 1. Applied to a variable valve timing device comprising a sprocket provided on said drive rotating body and a cam provided on said shaft, wherein said variable valve timing device changes the opening/closing timing of a valve by changing the rotational phase difference of said shaft with respect to said sprocket. 5. The electric actuator according to any one of 4 to 4.

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