WO2019181164A1

WO2019181164A1 - Actuator and driven gear reducer of variable compression ratio mechanism of internal combustion engine

Info

Publication number: WO2019181164A1
Application number: PCT/JP2019/001593
Authority: WO
Inventors: 健ブライアン池口; 正登真子
Original assignee: 日立オートモティブシステムズ株式会社
Priority date: 2018-03-19
Filing date: 2019-01-21
Publication date: 2019-09-26
Also published as: JP2019163698A

Abstract

The present invention has: a driving motor; a wave generator that is rotated by the motor and has a rotary shaft having a right-angled cross-section having a non-circular outer shape; a tubular part that is flexurally deformed in a non-circular shape by the rotation of the wave generator; a flexible external gear having external teeth that are provided on the outer circumference of the tubular part and have a tooth trace that is inclined with respect to the rotary shaft of the wave generator; an internal gear which is engaged with the flexurally deformed external teeth; a control shaft integrally rotates with the flexible external gear and is connected to a variable compression ratio mechanism; and a restriction part which restricts the movement of the flexible external gear in the direction of the rotary shaft when a torque is input to the control shaft from the variable compression ratio mechanism. Thus, the driving motor, which is the source of the torque, can be miniaturized, and energy can be saved.

Description

Actuator and wave gear reducer for variable compression ratio mechanism of internal combustion engine

The present invention relates to an actuator and a wave gear reducer for a variable compression ratio mechanism of an internal combustion engine.

Patent Document 1 has a control shaft of a variable compression ratio mechanism and an actuator that changes the rotational position of the control shaft, and the actuator reduces the rotational speed of a drive motor and transmits it to the control shaft. A machine is disclosed.

JP 2012-251446 A

However, in the above prior art, the wave gear device is combined with a drive motor which is a rotational force source, and the rotational force from the drive motor is decelerated and output to the control shaft. In addition, a rotational force is generated in the control shaft by input of motion from the internal combustion engine, and the rotational force is transmitted to the drive motor by inputting the rotational force to the wave gear. The drive motor must be able to output a rotational force that is greater than this rotational force. However, the volume and mass of the drive motor are larger than the output, so the drive motor is driven from the control shaft with a wave gear device. It is desirable to reduce the transmission of rotational force to the motor and to efficiently transmit the output from the drive motor to the control shaft.
However, as described above, since the wave gear device is a reversible gear mechanism, it is difficult to give a rotational force transmission efficiency difference larger than the speed ratio depending on the input direction.
One of the objects of the present invention is to provide an actuator and a wave gear reducer for a variable compression ratio mechanism of an internal combustion engine that can reduce the size of a drive motor that is a rotational force source and save labor.

In one aspect of the present invention, a drive motor, a wave generator that is rotated by the drive motor and has a non-circular outer shape in a cross section of the rotation axis, and is deformed to be deformed into a non-circular shape by the rotation of the wave generator. A flexible external gear having a flexible cylindrical portion, and external teeth provided on the outer periphery of the cylindrical portion and having tooth traces inclined with respect to the rotation axis of the wave generator; An internal gear that meshes with the deformed external teeth, a control shaft that rotates integrally with the flexible external gear and that is linked to the variable compression ratio mechanism, and a rotational force from the variable compression ratio mechanism to the control shaft. It has a restricting part that restricts movement of the flexible external gear in the direction of the rotation axis when input.

According to a preferred aspect of the present invention, the drive motor can be reduced in size and labor can be saved.

1 is a schematic view of an internal combustion engine provided with an actuator of a variable compression ratio mechanism to which the present invention is applied. It is a disassembled perspective view of the actuator of the variable compression ratio mechanism to which the present invention is applied. It is a side view of an actuator of a variable compression ratio mechanism to which the present invention is applied. FIG. 4 is a cross-sectional view taken along the line AA in FIG. 3 of the first embodiment. (A) is a front view of the flexible external gear of Embodiment 1, (b) is a right side view, and (c) is a CC cross-sectional view of (a). (A) is the D section enlarged view of FIG. 5, (b) is the figure which showed the wave gear shaft periphery moment component to the flexible external gear by the input direction of rotational force. FIG. 5 is an enlarged view of a portion B in FIG. 4 of the first embodiment. FIG. 4 is a cross-sectional view taken along line AA in FIG. 3 according to the second embodiment. FIG. 9 is an enlarged view of a portion E in FIG. 8 of the second embodiment.

Embodiment 1
FIG. 1 is a schematic view of an internal combustion engine provided with an actuator of a variable compression ratio mechanism to which the present invention is applied. The basic configuration is the same as that described in FIG. 1 of Japanese Patent Application Laid-Open No. 2011-169251 and will be described briefly.

Piston 1 reciprocates in a cylinder block cylinder in an internal combustion engine (gasoline engine). An upper link 3 is rotatably connected to the piston 1 via a piston pin 2. The lower link 5 is rotatably connected to the lower end of the upper link 3 via a connecting pin 6. A crankshaft 4 is rotatably connected to the lower link 5 via a crankpin 4a. An upper end portion of the first control link 7 is rotatably connected to the lower link 5 via a connecting pin 8. The lower end of the first control link 7 is connected to a connecting mechanism 9 having a plurality of links. The connection mechanism 9 includes a first control shaft 10, a second control shaft 11 as a control shaft or an output shaft, a second control link (actuator link) 12, and an arm link 13.

The first control shaft 10 is disposed in parallel with the crankshaft 4 disposed along the direction of the cylinder row included in the internal combustion engine.
The first control shaft 10 includes a first journal portion 10a, a control eccentric shaft portion 10b, an eccentric shaft portion 10c, a first arm portion 10d, and a second arm portion 10e. The first journal portion 10a is rotatably supported by the internal combustion engine body.
The control eccentric shaft portion 10 b is rotatably connected to the lower end portion of the first control link 7. The eccentric shaft portion 10 c is rotatably connected to one end portion 12 a of the second control link 12.
One end of the first arm portion 10d is connected to the first journal portion 10a. The other end of the first arm portion 10d is connected to the control eccentric shaft portion 10b. The control eccentric shaft portion 10b is located at a position eccentric by a predetermined amount with respect to the first journal portion 10a. One end of the second arm portion 10e is connected to the first journal portion 10a. The other end of the second arm portion 10e is connected to the eccentric shaft portion 10c.
The eccentric shaft portion 10c is at a position eccentric by a predetermined amount with respect to the first journal portion 10a. The other end 12b of the second control link 12 is connected to one end of the arm link 13 so as to be rotatable. The other end of the arm link 13 is connected to the second control shaft 11. The arm link 13 and the second control shaft 11 do not move relative to each other.
The second control shaft 11 is rotatably supported in a housing 20 described later via a plurality of journal portions.
The second control link 12 has a lever shape, and one end portion 12a connected to the eccentric shaft portion 10c is formed substantially linearly.

2 is an exploded perspective view of the actuator of the variable compression ratio mechanism to which the present invention is applied, FIG. 3 is a side view of the actuator of the variable compression ratio mechanism to which the present invention is applied, and FIG. FIG. 4 is a cross-sectional view taken along line AA in FIG.

As shown in the exploded perspective view of the actuator in FIG. 2, the arm link 13 is connected to the second control link 12 at the other end 12b formed in a curved shape. Further, an insertion hole 12c through which the eccentric shaft portion 10c is rotatably inserted is formed through the tip of the one end portion 12a. A connecting hole 12e is formed through the tip 12d of the other end 12b. In addition, the first arm portion 13b and the second arm portion 13b ′, which protrude from the annular portion 13d as the base portion of the arm link 13 toward the outer periphery and are formed in a bifurcated shape, have substantially the same diameter as the connecting hole 12e, respectively. The connecting hole 13c is formed through. The tip 12d of the second control link 12 is inserted between the first arm 13b and the second arm 13b 'formed in the forked shape of the arm link 13, and in this state, the connecting pin 14 is used for connecting The second control link 12 is connected to the arm link 13 by being inserted into the

holes

12e and 13c. The connecting pin 14 is press-fitted and fixed in the connecting hole 12e, but is slidably inserted into the connecting hole 13c.

The arm link 13 is formed separately from the second control shaft 11 as shown in FIG. The arm link 13 is a thick member formed of an iron-based metal material, and is formed in a forked shape by an annular portion 13d having a press-fitting hole 13a formed therethrough, and protruding from the annular portion 13d toward the outer periphery. The first arm portion 13b and the second arm portion 13b ′. In the press-fitting hole 13a formed in the annular part 13d, a fixing part 11b formed between each journal part of the second control shaft 11 is press-fitted, and the second control shaft 11 and the arm link 13 are connected by this press-fitting. It is fixed (see FIG. 4). A pair of connecting holes 13c are formed in each of the first arm part 13b and the second arm part 13b ′ that protrude from the annular part 13d and are bifurcated. Has been. The axial center of the connecting hole 13c (the axial center of the connecting pin 14) is eccentric from the axial center of the second control shaft 11 by a predetermined amount in the radial direction.

[Configuration of actuator of variable compression ratio mechanism]
As shown in FIGS. 2 to 4, the actuator 40 includes a drive motor 22, a wave gear reducer 50, a housing 20 including a first housing 20a and a second housing 20b, and a second control shaft 11 as a control shaft.
Hereinafter, the angle sensor 32 side is referred to as one end side, and the drive motor 22 side is referred to as the other end side.

[Operation of actuator of variable compression ratio mechanism]
The operation of the actuator 40 of the variable compression ratio mechanism will be briefly described.
The rotational position of the second control shaft 11 as the control shaft or the output shaft is changed by the torque transmitted from the drive motor 22 via the wave gear type speed reducer 50 that is a part of the actuator of the link mechanism for the internal combustion engine. . When the rotational position of the second control shaft 11 is changed, the posture of the second control link 12 is changed, the first control shaft 10 is rotated, and the position of the lower end portion of the first control link 7 is changed. Thereby, the attitude | position of the lower link 5 changes, the stroke position and stroke amount in the cylinder of piston 1 are changed, and an engine compression ratio is changed in connection with this.

[Configuration of drive motor]
The drive motor 22 is, for example, a brushless motor, and includes a motor casing 45, a motor drive shaft 48 as an input shaft, a coil 46, and a rotor 47. The motor casing 45 is formed in a bottomed cylindrical shape and is fixed to the second housing 20b. The coil 46 is fixed to the inner peripheral surface of the motor casing 45. The rotor 47 is rotatably disposed inside the coil 46. The motor drive shaft 48 is fixed to the center of the rotor 47. The motor drive shaft 48 is rotatably provided to the second housing 20 b and the motor casing 45 through two

ball bearings

51 and 52. The ball bearing 51 is fixed to the second housing 20b. The ball bearing 52 is fixed to the bottom of the motor casing 45. A tip 48a on one end side of the motor drive shaft 48 passes through the second housing 20b and is connected to the wave generating plug 371 of the wave generator 37 of the wave gear reducer 50. The second control shaft 11 is coaxial with the motor drive shaft 48. That is, the rotation axes P of the second control shaft 11 and the motor drive shaft 48 coincide. The distal end portion 11 a on the other end side of the second control shaft 11 is spline-coupled with the convex portion 362 a of the flexible external gear 36 of the wave gear reducer 50.
When the motor casing 45 is attached to the second housing 20b, the bolt 49 is inserted into the through hole 45b of the boss portion 45a, and the bolt 49 is tightened to the female screw portion formed on the drive motor 22 side of the second housing 20b. Thereby, the motor casing 45 is fixed to the second housing 20b. The motor housing chamber that houses the drive motor 22 by the motor casing 45 and the second housing 20b is configured as a drying chamber that does not supply lubricating oil or the like by the seal 100.

[Configuration of wave gear reducer]
The wave gear reducer 50 is attached to the housing 20. The wave gear reducer 50 includes a rigid internal gear 38, a flexible external gear 36, and a wave generator 37.
The rigid internal gear 38 is a rigid annular member having a plurality of internal teeth 38a on the inner periphery, and is fixed to the first housing 20a.
The flexible external gear 36 is disposed on the radially inner side of the rigid internal gear 38. The flexible external gear 36 is formed of a metal material and has a cylindrical portion 361 and a bottom portion 362. The cylindrical portion 361 is formed in a thin cylindrical shape that can be bent and deformed, and external teeth 361a are formed on the other axial end of the outer peripheral surface. The external teeth 361 a mesh with the internal teeth 38 a of the rigid internal gear 38. The number of teeth of the external teeth 361a is two fewer than the number of teeth of the internal teeth 38a. The bottom portion 362 extends radially inward from one axial end of the tubular portion 361. A small-diameter convex portion 362 a is formed on the inner periphery of the bottom portion 362. The convex portion 362a has a spline hole 362b. The tip portion (spline shaft) 11a of the second control shaft 11 is inserted into the spline hole 362b.

The outer peripheral surface of the wave generator 37 slides along the inner peripheral surface of the flexible external gear 36. The wave generator 37 includes a wave generation plug 371 and a ball bearing 372. The wave generating plug 371 has an elliptical cross-sectional shape in a direction orthogonal to the rotation axis thereof, and has an elliptical outer shape having a major axis portion having the largest radius and a minor axis portion having the smallest radius around the rotation axis P. Have. The wave generating plug 371 has a through hole 371b at the center. The front end 48a of the motor drive shaft 48 is fixed to the through hole 371b by press fitting. The ball bearing 372 allows relative rotation between the outer periphery of the wave generating plug 371 and the inner periphery of the flexible external gear 36. As shown in FIG. 4, the ball bearing 372 includes an inner ring 372a, an outer ring 372b, a plurality of balls 372c, and a cage 372d. The inner ring 372a is formed integrally with the outer peripheral surface of the wave generating plug 371. The outer ring 372 b is formed in a thin annular shape having flexibility, and is disposed on the inner periphery of the flexible external gear 36. The plurality of balls 372c are formed in a spherical shape and are disposed between the inner ring 372a and the outer ring 372b. The cage 372d is disposed between the inner ring 372a and the outer ring 372b, and keeps the interval between the balls 372c constant.

[Structure of housing]
As shown in FIGS. 2 to 4, the housing 20 including the first housing 20a and the second housing 20b is formed in a substantially cubic shape from an aluminum alloy material. A large-diameter annular opening groove 20c is formed on the other end side of the first housing 20a (see FIG. 4). The opening groove 20c is closed by the second housing 20b. The second housing 20b has a motor shaft through hole 20d through which the motor drive shaft 48 penetrates at a central position, and four boss portions 20e having a diameter expanded toward the radially outer side. The first housing 20a and the second housing 20b are fastened and fixed by inserting bolts 35 through bolt insertion holes formed through the boss 20e.
As shown in FIG. 3, the first housing 20a is formed with a pedestal portion 800 that protrudes in a radial direction away from the second control shaft 11 and on which an oil cooler (not shown) is installed. In this pedestal portion 800, oil that has passed through an oil filter (not shown) flows into the oil cooler from the oil inlet 800d, is cooled, and is then supplied from the oil outlet 800e to the engine side. A fixing surface 800g for fixing the oil cooler is formed on the upper surface of the pedestal portion 800, and the mating portion 800c formed around the oil inlet 800d side is thinned for weight reduction and formed in the center. A recess 800d is provided.

An opening for the second control link 12 connected to the arm link 13 is formed on a side surface orthogonal to the opening direction of the opening groove 20c. In the first housing 20a in which the opening is formed, a storage chamber 29 serving as an operation region of the arm link 13 and the second control link 12 is formed (see FIG. 4). Between the opening groove 20c and the storage chamber 29, a support hole 30b on the speed reducer side through which the second journal portion 11d of the second control shaft 11 passes is formed. A support hole 30 a through which the first journal portion 11 c of the second control shaft 11 passes is formed on the side surface in the axial direction of the storage chamber 29. A bearing 301 is disposed between the support hole 30a and the first journal portion 11c, and a bearing 304 is disposed between the support hole 30b and the second journal portion 11d.

At one end of the support hole 30a on the angle sensor 32 side, a retainer receiving hole 31 having a diameter larger than the opening of the support hole 30a is formed. Between the opening on the angle sensor 32 side of the support hole 30 a and the retainer accommodation hole 31, there is a step surface 31 a formed in a substantially perpendicular direction with respect to the second control shaft 11. The retainer 350 restricts the movement of the second control shaft 11 toward the other end side (wave gear type reduction gear side) in the direction of the rotation axis P by contacting the step surface 31a.

[Configuration of angle sensor]
The angle sensor 32 has a sensor holder 32 a attached so as to close the retainer receiving hole 31 from the outside of the housing 20. The sensor holder 32a has a flange portion 32a1 for fixing to the first housing 20a with a bolt 321. A seal ring 33 is provided between the sensor holder 32a and the first housing 20a to ensure liquid tightness between the retainer receiving hole 31 and the outside. In addition, a sensor cover 32c for closing the retainer accommodation hole 31 is provided outside the sensor holder 32a. A seal ring 323 is provided between the sensor cover 32c and the sensor holder 32a, and the bolt 34 is used to attach the sensor cover 32c to the sensor holder 32a so as to ensure liquid tightness between the retainer receiving hole 31 and the outside. To fix.
A rotor 32b is attached to the outer periphery of one end 11e of the second control shaft 11 in the rotation axis P direction. The rotor 32b is a substantially elliptical part. The angle sensor 32 detects that the distance set between the inner circumference of the sensor holder 32a and the rotor 32b has changed due to the rotation of the rotor 32b, based on a change in inductance of the detection coil. Thereby, the rotation position of the rotor 32b, that is, the rotation angle of the second control shaft 11 is detected. As described above, the angle sensor 32 is a so-called resolver sensor, and outputs rotation angle information to a control unit (not shown) that detects the engine operating state.

5A is a front view of the flexible external gear according to the first embodiment, FIG. 5B is a right side view, and FIG. 5C is a cross-sectional view taken along the line CC in FIG. 5A. 6A is an enlarged view of a portion D in FIG. 5, and FIG. 6B is a diagram showing a moment component around the wave gear axis to the flexible external gear according to the input direction of the rotational force. FIG. 7 is an enlarged view of a portion B in FIG. 4 of the first embodiment.

[Configuration of flexible external gear]
As shown in FIG. 5, the flexible external gear 36 is formed of a metal material and has a cylindrical portion 361 and a bottom portion 362. The cylindrical portion 361 is formed in a thin cylindrical shape that can be bent and deformed, and external teeth 361a are formed on one end side in the axial direction of the outer peripheral surface. The external teeth 361 a mesh with the internal teeth 38 a of the rigid internal gear 38. The number of teeth of the external teeth 361a is two fewer than the number of teeth of the internal teeth 38a. The bottom portion 362 extends radially inward from one axial end side of the tubular portion 361. A small-diameter convex portion 362 a is formed on the inner periphery of the bottom portion 362. The convex portion 362a has a spline hole 362b. The tip portion (spline shaft) 11a of the second control shaft 11 is inserted into the spline hole 362b.
Further, as shown in FIG. 6A, the tooth trace 361a1 is an external tooth 361a having a twist angle β with respect to the rotation axis P.
For this reason, as shown in FIG. 6B, when the rotational force F is input from the drive motor 22, the propulsive force F2 in the rotational direction and one end side in the rotational axis P direction (the second control shaft 11 side). Propulsive force F1 (thrust force) is generated.
In addition, by increasing the twist angle β, the propulsive force F1 (thrust force) to one end side (second control shaft 11 side) in the rotation axis P direction is increased.
As shown in FIG. 7, the flexible external gear 36 moves to one end side (solid arrow) in the rotation axis P direction by the propulsive force F <b> 1 toward the one end side (second control shaft 11 side) in the rotation axis P direction. Moving. In addition, this movement may cause contact with the flange 11 f of the second control shaft 11.
However, since the second control shaft 11 and the flexible external gear 36 are rotating in the same direction and at the same rotational speed, there is no problem with the control function for changing the engine compression ratio.

Further, as shown in FIG. 6B, when a large rotational force f generated by the variable compression mechanism from the second control shaft 11 (particularly, when the internal combustion engine expansion process, that is, when the piston 1 is lowered) is input. Thus, a propulsive force f2 in the rotational direction and a propulsive force f1 (thrust force) to the other end side (drive motor 22 side) in the direction of the rotational axis P are generated.
Note that the torsion angle β is set so that the flexible external gear 36 moves to the other end side (broken arrow) in accordance with the expansion process of the internal combustion engine, that is, the rotational direction of the input when the piston 1 is lowered. ing.
As shown in FIG. 7, the flexible external gear 36 is moved to the other end side in the rotation axis P direction by the propulsive force f1 (thrust force) toward the other end side (drive motor 22 side) in the rotation axis P direction. To the first abutting portion 371a as a restricting portion which is a flat portion formed in the wave generating plug 371 by surface contact.
The clearance a between the end of the convex portion 362a in the rotation axis P direction and the first abutting portion 371a is between the tip of the cylindrical portion 361 on the other end side in the rotation axis P direction and the outer ring 37a1 of the ball bearing 37a. It is set smaller than the clearance b.
For this reason, the convex part 362a will contact | abut to the 1st abutting part 371a reliably.
Here, since the flexible external gear 36 and the wave generating plug 371 have the opposite rotation directions and different rotational speeds, a large friction is generated in the flexible external gear 36 and the rotational force f is reduced. A braking action (sliding frictional force) that suppresses rotation occurs.
In particular, since the contact surfaces are in contact with each other, a large contact area can be obtained, so that a larger friction can be generated.
Thereby, when the rotational force f (the rotational force which an internal combustion engine generate | occur | produces) is input, the excessive input to the drive motor 22 can be suppressed.

Next, the function and effect will be described. The actuator of the variable compression mechanism of the internal combustion engine of Embodiment 1 has the following effects.

(1) With respect to the rotational axis P, a twist angle β is provided in the tooth trace 361a1 of the external tooth 361a of the flexible external gear 36, and a large rotational force is input to the second control shaft 11 from the variable compression mechanism of the internal combustion engine. A first abutting portion 371a that restricts the movement of the flexible external gear 36 to the other end side (the drive motor 22 side) in the rotation axis P direction when provided is provided.
Therefore, when a large rotational force is input from the variable compression mechanism to the external teeth 361a having the inclined torsion angle β, the flexible external gear 36 is moved to the other end side (drive motor 22 side) in the rotation axis P direction. It moves and comes into contact with the first abutting portion 371a, and a braking force (sliding frictional force) in the rotational direction is generated in the flexible external gear 36, so that excessive input to the drive motor 22 can be suppressed. .

(2) The expansion process of the internal combustion engine, that is, when a large rotational force generated when the piston 1 is lowered is input to the second control shaft 11, the other end side in the direction of the rotation axis P (drive motor 22 side), that is, the first A twist angle β is provided in the tooth trace 361a1 of the external tooth 361a so that the flexible external gear 36 moves in the direction of the one abutting portion 371a.
Therefore, since it was made to respond | correspond at the time of the expansion | swelling process of the internal combustion engine in which especially big rotational force generate | occur | produces, the excessive input to the drive motor 22 can be suppressed more.

(3) The first abutting portion 371a as the restricting portion is provided on the side surface which is the plane of the wave generating plug 371 of the wave generator 37 so as to contact the convex portion 362a of the flexible external gear 36.
Therefore, since the wave generator 37 and the flexible external gear 36 whose rotation directions are opposite to each other are brought into contact with each other, and the wave generation plug 371 and the convex portion 362a are in surface contact with each other over a wide plane, a larger braking force ( Sliding friction force) can be generated, and excessive input to the drive motor 22 can be further suppressed.

(4) The clearance a between the convex portion 362 a of the flexible external gear 36 and the first abutting portion 371 a of the wave generating plug 371 of the wave generator 37 is different from the cylindrical portion 361 of the flexible external gear 36. The clearance is set smaller than the clearance b between the tip on the end side and the ball bearing 372.
Therefore, the convex part 362a of the flexible external gear 36 and the first abutting part 371a of the wave generation plug 371 can be reliably brought into contact with each other.

[Embodiment 2]
8 is a cross-sectional view taken along the line AA of FIG. 3 of the second embodiment, and FIG. 9 is an enlarged view of a portion E of FIG. 8 of the second embodiment.

Since the basic configuration of the second embodiment is the same as that of the first embodiment, the same components as those of the first embodiment are denoted by the same reference numerals, description thereof is omitted, and only portions different from the first embodiment will be described.
As shown in FIG. 9, the clearance a between the convex part 362a and the first abutting part 371a is set larger than the clearance b between the tip of the other end side of the cylindrical part 361 and the outer ring 37a1 of the ball bearing 37a. Yes.
Therefore, as described above, when a large rotational force f generated by the variable compression mechanism from the second control shaft 11 (particularly when the expansion process of the internal combustion engine, that is, when the piston 1 is lowered) is input, the rotational direction Propulsive force f2 and propulsive force f1 (thrust force) to the other end side (drive motor 22 side) in the rotation axis P direction are generated.
Due to the propulsive force f1 (thrust force) toward the other end side (drive motor 22 side) in the direction of the rotation axis P, the flexible external gear 36 moves to the drive motor 22 side (broken arrow) and has a smaller clearance. By b, the tip of the cylindrical portion 361 on the other end side in the rotation axis P direction comes into surface contact with the second abutting portion 37a1a as a restricting portion which is a flat portion formed on the outer ring 37a1 of the ball bearing 37a. It will be.
Here, the outer ring 37a1 of the ball bearing 37a is fixed to the second housing 20b, and a relative rotation speed is generated with the tip of the cylindrical portion 361 on the other end side in the rotation axis P direction. A large friction is generated in 36, and a braking action (sliding frictional force) for suppressing the rotation is generated with respect to the rotational force f.
Therefore, in the second embodiment, the same operational effects as in the first embodiment are obtained.

[Other Embodiments]
Although the embodiment for carrying out the present invention has been described above, the specific configuration of the present invention is not limited to the configuration of the embodiment, and there are design changes and the like within the scope not departing from the gist of the invention. Are also included in the present invention.
For example, the wave gear reducer of the present invention is particularly suitable as an actuator reducer for a variable compression ratio mechanism of an internal combustion engine, but is described in Japanese Patent Application Laid-Open Nos. 2015-1190 and 2011-231700. The present invention is also applicable to a valve timing control device for an internal combustion engine and a variable steering angle mechanism capable of changing a steering angle with respect to a steering angle.
In the first and second embodiments, the torsion angle β is set so as to move the flexible external gear 36. However, even with the external teeth 361a having the torsion angle β of “0”, the propulsive force in the direction of the rotation axis P (thrust Therefore, the twist angle β may be set so that the flexible external gear 36 is almost stationary.
As a result, the durability of the ball bearing 372 can be improved, the thrust plate and the like can be reduced, and the number of parts can be reduced, thereby improving productivity.

The technical ideas that can be grasped from the embodiments described above are described below.
An actuator of a variable compression ratio mechanism of an internal combustion engine and a wave gear reducer, in one aspect thereof, are an actuator of a variable compression mechanism of an internal combustion engine, and are rotated by a drive motor and the drive motor at a right-angle cross section of a rotation axis. A wave generator having a non-circular outer shape, a flexible cylindrical portion that is bent and deformed into a non-circular shape by the rotation of the wave generator, and the wave generation provided on an outer periphery of the cylindrical portion An external tooth having a tooth trace inclined with respect to the rotation axis of the vessel, an internal gear with which the external tooth deformed by bending is engaged, and the flexible external gear rotating together. A control shaft linked to the variable compression ratio mechanism; and a restricting portion for restricting movement of the flexible external gear in the direction of the rotation shaft when a rotational force is input from the variable compression ratio mechanism to the control shaft; ,
Have
In a more preferred aspect, in the above aspect, the tooth trace of the flexible external gear is inclined so that a thrust force is generated in a direction toward the restricting portion.
In still another preferred aspect, in any one of the above aspects, the flexible external gear has a bottomed cylindrical shape having a bottom portion provided radially inward at one end in the rotation axis direction of the cylindrical portion. And a convex portion extending from the bottom portion to the other end side of the cylindrical portion in the rotational axis direction, and the restricting portion is a first abutment of the wave generator capable of contacting the convex portion from the rotational axis direction Part.
In a more preferred aspect, in the above aspect, the wave generator is disposed on the outer periphery of the wave generation plug, which is rotated by the drive motor and has an elliptical outer shape in a cross section at a right angle. And the first abutting portion is a flat portion provided in the wave generating plug.
In still another preferred aspect, in the above aspect, the cylindrical part has a portion facing the other end in the rotation axis direction, and the first clearance between the convex part and the first abutting part is the cylindrical part. It is smaller than the second clearance between the other end in the rotation axis direction of the shape portion and the opposed portion.
In still another preferred aspect, in the above aspect, the restricting portion is a second abutting portion capable of abutting on the cylindrical portion from the axial direction.
In still another preferred embodiment, the wave gear device is an input shaft, a wave generator that rotates integrally with the input shaft and has an elliptical cross section perpendicular to the axis, and is flexibly deformed by the rotation of the wave generator. A flexible external gear having a flexible cylindrical portion and external teeth provided on the outer periphery of the cylindrical portion and having tooth traces inclined with respect to the rotation axis of the wave generator; An external gear that meshes with the deformed external teeth, and an output shaft that rotates integrally with the flexible external gear. When a rotational force is input to the input shaft, the output shaft When the rotational force is input, the direction of the thrust force acting on the flexible external gear is reversed.
In a more preferable aspect, in the above aspect, a restriction portion is provided that restricts movement of the flexible external gear in the rotation axis direction when a rotational force is input to the output shaft.
In a more preferred aspect, in the above aspect, the flexible external gear has a bottomed cylindrical shape having a bottom portion at one end portion in the rotation axis direction of the cylindrical portion, and the restriction portion has a rotation shaft at the bottom portion. It is the 1st butting part contact | abutted from a direction.
In a more preferred aspect, in the above aspect, the flexible external gear has a convex part that projects from the bottom part to the inside of the cylindrical part, and the first abutting part is provided in the wave generator. ing.
In a more preferred aspect, in the above aspect, the wave generator rotates integrally with the input shaft, the wave generating plug having an elliptical cross-sectional outer shape, an outer periphery of the wave generating plug, and the A ball bearing disposed between the inner sides of the cylindrical portion, and the first abutting portion is a flat portion provided in the wave generating plug.
In still another preferred aspect, in the above aspect, the restricting portion is a second abutting portion that abuts the cylindrical portion from the axial direction.

DESCRIPTION OF SYMBOLS 11 ... 2nd control shaft (control shaft, output shaft), 50 ... Wave gear reducer, 22 ... Drive motor, 38 ... Rigid internal gear, 38a ... Internal tooth, 36 ... Flexible external gear, 361 ... Cylindrical part , 361a ... external teeth, 361a1 ... tooth traces, 362 ... bottom 362a ... convex part, 37 ... wave generator, 371 ... wave generation plug, 371a ... first abutting part (regulator), 372 ... ball bearing, 37a1a ... Second abutting portion (regulating portion), 48 ... motor drive shaft, a ... first clearance, b ... second clearance, 48 ... motor drive shaft (input shaft)

Claims

An actuator for a variable compression mechanism of an internal combustion engine,
A drive motor;
A wave generator that is rotated by the drive motor and has a non-circular outer shape in a right-angle cross section of the rotation axis;
A flexible cylindrical portion that is bent and deformed in a non-circular shape by rotation of the wave generator, and a tooth trace that is provided on the outer periphery of the cylindrical portion and is inclined with respect to the rotation axis of the wave generator. An external tooth having a flexible external gear,
An internal gear that meshes with the deformed external teeth;
A control shaft that rotates integrally with the flexible external gear and that is linked to the variable compression ratio mechanism;
A restricting portion for restricting movement of the flexible external gear in the direction of the rotation shaft when a rotational force is input to the control shaft from the variable compression ratio mechanism;
Having
An actuator for a variable compression ratio mechanism of an internal combustion engine.
An actuator for a variable compression ratio mechanism for an internal combustion engine according to claim 1,
The tooth traces of the flexible external gear are inclined so that a thrust force is generated in a direction toward the restricting portion by the rotation of the wave generator or the rotation of the control shaft.
An actuator for a variable compression ratio mechanism of an internal combustion engine.
An actuator of a variable compression ratio mechanism for an internal combustion engine according to claim 2,
The flexible external gear has a bottomed cylindrical shape having a bottom portion provided radially inward at one end of the cylindrical portion in the rotation axis direction, and has a bottom portion in the rotation axis direction of the cylindrical portion from the bottom portion. Having a convex portion extending to the end side,
The restricting portion is a first butting portion of the wave generator that can come into contact with the convex portion from the direction of the rotation axis.
An actuator for a variable compression ratio mechanism of an internal combustion engine.
An actuator for a variable compression ratio mechanism for an internal combustion engine according to claim 3,
The wave generator has a wave generating plug that is rotated by the drive motor and has an elliptical outer shape of a right-angle cross section of the rotation shaft, and a ball bearing disposed on the outer periphery of the wave generating plug,
The first abutting portion is a flat portion provided in the wave generating plug,
An actuator for a variable compression ratio mechanism of an internal combustion engine.
An actuator for a variable compression ratio mechanism for an internal combustion engine according to claim 3,
Having a portion facing the other end of the cylindrical portion in the rotation axis direction;
The first clearance between the convex portion and the first abutting portion is smaller than the second clearance between the other end in the rotation axis direction of the cylindrical portion and the facing portion.
An actuator for a variable compression ratio mechanism of an internal combustion engine.
An actuator for a variable compression ratio mechanism for an internal combustion engine according to claim 3,
The restricting portion is a second abutting portion capable of contacting the cylindrical portion from the axial direction.
An actuator for a variable compression ratio mechanism of an internal combustion engine.
A wave gear device,
An input shaft;
A wave generator that rotates integrally with the input shaft and has an elliptical cross section perpendicular to the axis;
An external tooth having a flexible cylindrical portion that is bent and deformed by the rotation of the wave generator, and a tooth trace that is provided on the outer periphery of the cylindrical portion and is inclined with respect to the rotation axis of the wave generator. A flexible external gear having:
An internal gear that meshes with the deformed external teeth;
An output shaft that rotates integrally with the flexible external gear;
Have
The direction of the thrust force acting on the flexible external gear is reversed between when the rotational force is input to the input shaft and when the rotational force is input to the output shaft.
A wave gear device.
The wave gear device according to claim 7,
A restricting portion for restricting movement of the flexible external gear in the direction of the rotation axis when a rotational force is input to the output shaft;
A wave gear device.
The wave gear device according to claim 8,
The flexible external gear is a bottomed cylindrical shape having a bottom portion at one end portion in the rotation axis direction of the cylindrical portion,
The restricting portion is a first abutting portion that comes into contact with the bottom portion from the direction of the rotation axis.
A wave gear device.
The wave gear device according to claim 9,
The flexible external gear has a convex portion projecting from the bottom portion to the inside of the cylindrical portion, and the first abutting portion is provided in the wave generator.
A wave gear device.
The wave gear device according to claim 10,
The wave generator rotates integrally with the input shaft, and is disposed between a wave generating plug whose outer shape of a right-angle cross section of the rotating shaft is an ellipse, and an outer periphery of the wave generating plug and the inside of the tubular portion. A ball bearing,
The first butting portion is a flat portion provided in the wave generating plug.
A wave gear device.
The wave gear device according to claim 8,
The restricting portion is a second abutting portion that comes into contact with the cylindrical portion from the axial direction.
A wave gear device.