JP2714429B2 - Wave gear device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wave gear device, and more particularly to an improvement of a wave generator using a piezoelectric element among wave generators used in a wave gear device.

[Conventional technology]

A typical wave gear device includes a rigid circular internal gear, and a non-circular (often elliptical) shape formed inside the internal gear so as to mesh with the internal gear at two places, and the tooth of the internal gear is formed. A flexible external gear having 2n (n is a positive integer) smaller number of teeth than a number thereof, and a wave generator which fits inside the flexible external gear and deflects the flexible external gear into a non-circular shape Consists of For example, the rigid circular internal gear is fixed, the input shaft connected to the wave generator is rotated, and when the wave generator is rotated, the flexible external gear and the rigid circular internal gear that are elastically deformed into an elliptical shape when rotated. The meshing position moves sequentially. When the wave generator makes one rotation, the flexible external gear moves in the direction opposite to the rotation direction of the wave generator by 2n less teeth than the rigid circular internal gear, and this movement is used as an output to output the flexible external gear. It can be taken out from the output shaft connected to the gear.

Note that the same effect as described above can be obtained even if the rigid circular gear is formed as an external gear and the flexible gear is formed as an internal gear.

As the wave generator, those composed of an elliptical plate and a flexible bearing fitted on the outer periphery of the plate were often used. However, the inertia mass was large and the response characteristics were poor, so Has developed a wave generator that improves this point in Japanese Patent Application No. 62-3169.
No. 99 proposed. FIGS. 13 and 14 show a wave gear device provided with this wave generator. The wave gear device 10 includes a rigid circular internal gear 11, a flexible external gear 12 meshing with the circular internal gear 11.
And a wave generator 13 for bending the flexible external gear 12 into an elliptical shape. The wave generator 13 includes a disk 15 disposed inside the flexible external gear 12 and an outer periphery of the disk 15. And piezoelectric elements 16 radially arranged at substantially equal intervals. When a predetermined voltage is applied, the piezoelectric element 16 protrudes radially outward of the disk 15. For this reason, the flexible external gear 12 is formed by urging two piezoelectric elements 16 diametrically opposed to the disk 15, for example, the piezoelectric elements A ₁ and A ₂ using the piezoelectric element driving device 17.
It can be bent into an elliptical shape having A ₁ and A ₂ as major axes. Hereinafter, a pair of two piezoelectric elements 16 that are diametrically opposed by the piezoelectric element driving device 17 are, for example, clockwise, that is, (B ₁ , B ₂ ), (C ₁ , C ₂ ), (D ₁ , D ₂₎ ), The meshing position of the circular internal gear 11 and the flexible external gear 12 sequentially moves, and a relative rotation occurs between the circular internal gear 11 and the flexible external gear 12, Output shaft 18 connected to a flexible external gear 12
Can be taken out as output.

[Problems to be solved by occurrence]

However, the displacement of the piezoelectric element in this wave generator was small enough to bend the flexible gear into an elliptical shape.

In view of this point, the present invention can amplify the displacement of the piezoelectric element and sufficiently deflect the flexible gear into an elliptical shape, and further need to change the direction of the displacement when amplifying the displacement. Therefore, an object of the present invention is to provide a wave gear device that can change the direction of displacement when necessary.

[Means for solving the problem]

In order to achieve this object, a wave generator of a wave gear device according to the present invention comprises a displacement generating means, a displacement amplifying means for amplifying a displacement generated by the displacement generating means, and, if necessary, a displacement generating means. And a displacement direction changing means for changing the direction of the displacement generated by the above. Among them, the displacement amplifying means is based on the so-called "lever principle".

The displacement generating means includes a plurality of piezoelectric elements radially arranged at substantially equal intervals on the circumference of a circle centered on the flexspline so that the displacement direction forms a fixed angle with respect to the axis of the flexspline. A piezoelectric element driving device for sequentially selecting and energizing the piezoelectric elements. Except when the displacement direction of the piezoelectric element is perpendicular to the axis of the flexspline, the displacement direction of the piezoelectric element does not match the direction in which the flexspline bends. Is provided at least.

The displacement amplifying means includes a member having a portion abutting on the piezoelectric element, at least one displacement amplifying mechanism, and a portion abutting on the back surface of the tooth surface of the flexspline. The displacement amplification mechanism is composed of a member having a portion that receives a displacement, a portion that acts as a fulcrum, and a portion that transmits the amplified displacement. It is longer than the distance between the part acting as a part and the part receiving the displacement.

The displacement direction changing means has two configurations. One is a member having two parts extending in two directions from one point, and fixed at any position so as to act as a fulcrum. The other end is connected to a portion of the displacement amplification mechanism that transmits the amplified displacement, and the other end is formed of a fixed elastic member, and the direction of the displacement transmitted by the portion that transmits the amplified displacement is fixed to the other end. It is the direction to go.
These displacement direction changing means perform the function of changing the displacement direction and amplifying the displacement at the same time.

Further, as one in which displacement amplification and displacement direction change are simultaneously performed by one means, an elastic member having one end connected to the piezoelectric element and the other end fixed is provided, and the direction of displacement of the piezoelectric element is fixed at the other end. It is also possible to use a displacement amplification / displacement direction changing means which is a direction toward.

(Operation)

According to the above structure of the present invention, the displacement of the piezoelectric element can be amplified and, if necessary, the direction of the displacement can be changed. To engage with the rigid circular gear.

〔Example〕

1 to 11 show an embodiment of a wave gear device according to the present invention. Each of these wave gear devices 1 includes a circular spline 2, a flexspline 3, and a wave generator 4 which bends the flexspline 3 into an elliptical shape and partially meshes with the circular spline 2. The flexspline 3 has a cup-like shape, and is connected to the output shaft 5 at a closed end thereof.

[Example I]

1 (a) and 1 (b) show an embodiment of a wave gear device 1 provided with a wave generator 4 comprising a displacement generating means 6 and a displacement amplifying means 7. FIG. FIG. 2A is a cross-sectional view when cut along a plane passing through the axis of the flexspline 3, and FIG. 1B is a cross-sectional view taken along line XX of FIG.
In the wave gear device shown in FIG. 1, the flexspline 3 is an external gear, and the circular spline 2 is an internal gear.

The displacement generating means 6 includes twelve piezoelectric elements 21 and the piezoelectric elements 21.
And a piezoelectric element driving device (not shown) for sequentially selecting and energizing 21. As shown in FIG. 1 (b), the piezoelectric element
Numeral 21 is arranged so that the direction of displacement is radial at substantially equal intervals around the axis of the flexspline 3 on a plane perpendicular to the axis of the flexspline 3, and the direction of displacement is oriented toward the axis of the flexspline 3. ing.

The displacement amplifying means 7 is composed of a member having a portion 31 that abuts on the piezoelectric element 21, two displacement amplifying mechanisms 32a and 32b, and a portion 33 that abuts on the back surface of the tooth surface of the flexspline 3.

FIGS. 2A and 2B show two examples of the displacement amplification mechanism. The displacement amplifying mechanism 32 includes a portion 51 that receives the displacement.
And a portion 52 fixed at the position with a hinge 70 and acting as a fulcrum, and a portion 53 transmitting the amplified displacement.
And a member having: Distance L ₁ between the portion 53 to convey the displacement is amplified portion 52 acting as a fulcrum is longer than the distance L ₂ between the portion 51 for receiving the displaced portion 52 which acts as a fulcrum. Thus, by the so-called "the principle of leverage", the portion 51 for receiving the displacement FIG (a), receives the displacement X ₁ in the direction shown in (b), from the portion 53 to convey the amplified displacement the displacement X ₁ in the direction and FIG. (a) in the opposite direction, in the same figure (b) can be obtained displacement X ₂ in the same direction. In this case, since X ₂ = (L ₁ / L ₂ ) X ₁ and L ₁ > L ₂ , the displacement X ₂ is amplified more than the first displacement X ₁ .

The portion 51 that receives the displacement is the portion 31 that contacts the piezoelectric element 21.
, Or receives a displacement by being connected to a portion 53 of another displacement amplification mechanism 32 that transmits the amplified displacement. On the other hand, the portion 53 that transmits the amplified displacement is connected to the portion 51 that receives the displacement of the other displacement amplifying mechanism 32 to further amplify the displacement, or the portion 53 that contacts the back surface of the tooth surface of the flexspline 3 and The displacement is transmitted to the flank of the flexspline 3 as a unit, and the flexspline 3 is flexed non-circularly.

The wave gear device 1 having the above configuration and shown in FIGS. 1 (a) and 1 (b) operates as follows. When the piezoelectric element 21 is displaced in the axial direction of the flexspline 3, the displacement is amplified by the displacement amplifying mechanism 32a and further amplified again by the displacement amplifying mechanism 32b. The portion of the displacement amplifying mechanism 32b that transmits the amplified displacement is integrated with a portion 33 that abuts on the back surface of the tooth surface of the flexspline 3, and the amplified displacement is a portion 33 that abuts on the back surface of the tooth surface of the flexspline 3. To the flexspline 3 via As a result, the flexspline 3 is bent in a non-circular shape, and the position where the flexspline 3 and the circular spline 2 mesh with each other is moved by sequentially urging the piezoelectric elements 21 in, for example, a clockwise direction by the piezoelectric element driving device. Axis 5
The output can be extracted from. In this case,
Since the displacement direction of the piezoelectric element 21 is parallel to the flexing direction of the flexspline 3, it is not necessary to change the displacement direction.

Although the above embodiment relates to a wave gear device in which the flexspline 3 is an external gear and the circular spline 2 is an internal gear, a wave gear device in which the flexspline 3 is an internal gear and the circular spline 2 is an external gear is also applicable. It is within the scope of the present invention.

3 (a) and 3 (b) show an embodiment of a wave gear device in which the flexspline 3 is an internal gear and the circular spline 2 is an external gear. FIG. 3A shows flex spline 3.
Sectional view when cut along a plane passing through the axis of FIG.
FIG. 2 is a sectional view taken along line XX of FIG. In this embodiment, the structure is the same as that of the previous embodiment, except that the portion where the urged piezoelectric element 21 contacts the flexspline 3 has an elliptical minor axis, and operates similarly.

(Example II)

FIGS. 4 (a) and (b) and FIGS. 5 (a) and (b) each include a wave generator 4 including a displacement generating means 6, a displacement amplifying means 7 and a displacement direction changing means 8. 1 shows an embodiment of a wave gear device 1 according to the present invention. FIG. 4 (a) and FIG. 5 (a)
Is a cross-sectional view taken along a plane passing through the axis of the flexspline 3, and FIG. 2B is a cross-sectional view taken along line XX of FIG.

The displacement generating means 6 includes twelve piezoelectric elements 21 and the piezoelectric elements 21.
And a piezoelectric element driving device (not shown) for sequentially selecting and energizing 21. As shown in FIGS. 4 (a) and (b) and FIGS. 5 (a) and (b), the piezoelectric element 21 is moved around its axis so that the displacement direction is parallel to the axis of the flexspline 3. The wave gear device 1 shown in FIG. 5 is arranged so as to radiate at substantially equal intervals on the circumference of the circle to be moved, and so that the displacement direction is directed toward the closed end of the flexspline 3 in the wave gear device 1 shown in FIG. Is arranged so as to be directed away from the closed end of the flexspline 3.

The displacement amplifying means 7 is composed of a member having a portion 31 abutting on the piezoelectric element 21, a displacement amplifying mechanism 32, and a portion 33 abutting on the inner surface of the flexspline 3. The structure of the displacement amplifying mechanism 32 is shown in FIG. Same as the one.

The displacement direction changing means 8 has two parts extending from one point in two directions, and is made of a member fixed so that either position acts as a fulcrum. Displacement direction changing means 8
FIGS. 6 (a) and 6 (b) show two examples. The displacement direction changing means 8 has two portions 62 and 63 extending in two directions at a right angle from a point 61 and is fixed at a position 64 via a hinge 70. In FIG. 6B, the point 61 and the fixed position 64 coincide with each other. Here, FIG. 6 (a),
Given the horizontal displacement X ₁ at point 65 (b), the portion 63 of the fixed position 64 as a fulcrum is swung in the clockwise direction in FIG. Accordingly, the portion 62 also swings in the clockwise direction, the tip portion 62 66 conveys the displacement X ₂ in the vertical direction. Direction of displacement X ₂ If the direction of displacement X ₁ is accustomed to the contrary also reversed. Thus, the displacement direction changing means 8 changes the direction of displacement. Two parts 6
The angle formed by 2, 63 is not limited to a right angle, and any angle can be selected.

The point 65 which receives the displacement receives the displacement of the piezoelectric element 21 by being connected to the piezoelectric element 21 or receives the amplified displacement by being connected to the portion 53 of the displacement amplifying mechanism 32 which transmits the amplified displacement. The tip 66 for transmitting the displacement is connected to the portion 51 of the displacement amplifying mechanism 32 that receives the displacement, and transmits the displacement to the displacement amplifying mechanism 32 to further amplify the displacement, or the tip of the flex spline 3 of the displacement amplifying means 7 The displacement is transmitted to the flexspline 3 integrally with the portion 33 abutting on the back surface to flex the flexspline 3 in a non-circular shape.

The displacement direction changing means 8 can be used as the displacement amplifying means 7 at the same time. The distance between the fixed position 64 acting as a fulcrum and the point 66 transmitting the displacement is L ₁ , the fixed position
Assuming that the distance between the point 64 and the point 65 to be displaced is L ₂ , when the angle between the two portions 62 and 63 is 90 degrees, X ₂ ≒ (L ₁
/ L ₂ ) Since X ₁ can be approximated, the displacement direction changing means 8 can also be used as the displacement amplifying means 7 by setting L ₁ > L ₂ .

Although the hinge 70 may be mounted in any direction, it is most preferably a diagonal direction of a rectangle having two sides L ₁ and L ₂ as shown by a broken line in FIG. 6B.

The wave gear device 1 having the above configuration operates as follows. In the wave gear device shown in FIG. 4, when the piezoelectric element 21 is displaced toward the closed end of the flexspline 3, the displacement is amplified by the displacement amplification mechanism 32, and the displacement direction is changed by the displacement direction changing means 8. And the displacement is amplified. In the wave gear device of FIG.
When the piezoelectric element 21 is displaced in the direction away from the closed end of the flexspline 3, the displacement is changed by the displacement direction changing means 8, the displacement is amplified, and the displacement is amplified by the displacement amplification mechanism 32. . Further, in both FIG. 4 and FIG. 5, the amplified displacement is the portion of the flexspline 3 that abuts against the rear surface of the gear.
To the flexspline 3 via As a result, the flexspline 3 is bent in a non-circular shape, and the position where the flexspline 3 and the circular spline 2 mesh with each other is moved by sequentially urging the piezoelectric elements 21 in, for example, a clockwise direction by the piezoelectric element driving device. The output can be taken from the shaft 5.

Although the above embodiment is an example of a wave gear device in which the flex spline 3 is an external gear and the circular spline 2 is an internal gear, as in the case of the embodiment I, the flex spline 3 is an internal gear and the circular spline 2 is an external gear. It is also possible to use a wave gear device in the form of a gear. FIG. 7 (a),
(B) shows a wave gear device of this type. The configuration is the same as that of the above-described embodiment except that the portion of the flexspline 3 where the urged piezoelectric element 21 abuts has an elliptical minor axis, and the same operation can be obtained.

(Example III)

FIGS. 8 (a) and 8 (b) show an embodiment of the wave gear device 1 provided with the wave generator 4 including the displacement generating means 6, the displacement amplifying means 7 and the displacement direction changing means 8. . FIG. 2A is a cross-sectional view taken along a plane passing through the axis of the flexspline 3, and FIG. 1B is a cross-sectional view taken along line XX of FIG.

The displacement generating means 6 includes twelve piezoelectric elements 21 and the piezoelectric elements 21.
And a piezoelectric element driving device (not shown) for sequentially selecting and energizing 21. As shown in FIGS. 8 (a) and (b),
The piezoelectric elements 21 of the displacement generating means 6 are radially arranged at substantially equal intervals on a circle around the axis so that the displacement direction is parallel to the axis of the flexspline 3, and the displacement direction is Are arranged in a direction away from the closed end of the.

The displacement amplifying means 7 is composed of a member having a portion 31 abutting on the piezoelectric element 21 and four displacement amplifying mechanisms 32a, 32b, 32c, 32d. The structure of the displacement amplifying mechanism is the same as that of the wave gear device of FIG. The same is true.

The displacement direction changing means 8 includes an elastic member 40. One end 40a of the elastic member 40 is fixed, and the other end 40b is a displacement amplification mechanism.
It is connected to a portion 53 that transmits the amplified displacement of 32d. The direction of the displacement transmitted by the portion 53 transmitting the amplified displacement is the direction of the fixed end 40a. One end 40a of the elastic member 40 is fixed when the displacement is transmitted from the portion 53 transmitting the amplified displacement of the displacement amplification mechanism 32d to the one end 40b of the elastic member 40 in the direction of the fixed end 40a, that is, in the left direction in the drawing. So
The elastic member 40 is bent in an arc shape so as to be convex in the direction of the circular spline 2 (vertical direction in the figure) with both ends 40a and 40b as end portions. In this way, the displacement generated in the horizontal direction in the figure from the displacement generating means 6 is changed in the vertical direction at the portion of the flexspline 3 that contacts the rear surface of the tooth surface.

Since the amount of deflection at the center of the elastic member 40 can be increased by increasing the length of the elastic member 40, the displacement direction changing means 8 including the elastic member 40 is also used as the displacement amplification means 7. can do.

The wave gear device 1 having the above configuration operates as follows. When the piezoelectric element 21 is displaced away from the closed end of the flexspline 3, the displacement is amplified by the four displacement amplifying mechanisms 32a, 32b, 32c, 32d. Further, the direction of displacement is changed by the elastic member 40 and the displacement is amplified. The amplified displacement is flex spline 3
The flexspline 3 is transmitted to the inner surface, and is flexed non-circularly. For this reason, the piezoelectric element 21 is driven by the piezoelectric element driving device.
For example, by sequentially energizing in the clockwise direction, the position where the flexspline 3 and the circular spline 2 mesh with each other moves, and the output can be taken out from the output shaft 5.

In the above embodiment, the flex spline 3 is an external gear and the circular spline 2 is a wave gear device of an internal gear type.
Can be formed as an internal gear and the circular spline 2 as an external gear to form a wave gear device.

In addition, as shown in FIG. 8A, not only is the piezoelectric element 21 arranged so that the displacement direction of the piezoelectric element 21 is parallel to the axis of the flexspline 3, but also the displacement direction of the piezoelectric element 21 is Can be arranged so as to form a fixed angle with respect to. In this case, the displacement amplification mechanism
One or more displacement direction changing means 8 shown in FIG. 6 (a) or (b) is used so that the direction of the displacement transmitted by the portion 53 transmitting the amplified displacement of 32d is the direction of the fixed end 40a.

(Example IV)

FIGS. 9 (a) and 9 (b) show an embodiment of the wave gear device 1 provided with the wave generator 4 comprising the displacement generating means 6 and the displacement amplification and displacement direction changing means 9. FIG. FIG. 2A is a cross-sectional view taken along a plane passing through the axis of the flexspline 3, and FIG. 1B is a cross-sectional view taken along line XX of FIG.

The displacement generating means 6 has the same configuration as the displacement generating means of the wave gear device 1 shown in FIG.

The displacement amplification and displacement direction changing means 9 includes an elastic member 40, one end 40a of the elastic member 40 is fixed, and the other end 40b is connected to the piezoelectric element 21 via an appropriate connecting member 41. The direction of displacement of 21 is the direction of the fixed end 40a. The length of the elastic member 40 in the axial direction of the flexspline 3 is sufficiently long with respect to the displacement applied by the piezoelectric element 21.

When displacement is transmitted from the piezoelectric element 21 to one end 40b of the elastic member 40 in the direction of the fixed end 40a, that is, rightward in the figure, the one end 40a of the elastic member 40 is fixed, and the elastic member
With the ends of 0a and 40b as end portions, they are bent in an arc shape so as to be convex in the direction of the circular spline 2 (vertical direction in the drawing). In this case, since the length of the elastic member 40 is sufficiently long with respect to the displacement given by the piezoelectric element 21, the amount of deflection at the center of the elastic member 40 can be increased. In this manner, the displacement generated in the horizontal direction in the figure from the displacement generating means 6 is changed in direction in the vertical direction at the portion in contact with the inner surface of the flexspline 3, and the displacement is amplified.

The wave gear device 1 having the above configuration operates as follows. When the piezoelectric element 21 is displaced away from the closed end of the flexspline 3, the displacement is
As a result, the displacement direction is changed and the displacement is amplified. The amplified displacement is transmitted to the inner surface of the flexspline 3, and the flexspline 3 is bent in a non-circular shape. For this reason, the position where the flexspline 3 and the circular spline 2 mesh with each other is moved by sequentially urging the piezoelectric elements 21 in a clockwise direction by the piezoelectric element driving device, for example.
An output can be taken out from the output shaft 5.

In the above embodiment, the flex spline 3 is an external gear, and the circular spline 2 is a wave gear device in the form of an internal gear.
Can be formed as an internal gear and the circular spline 2 as an external gear to form a wave gear device.

Further, as shown in FIG. 9 (a), not only is the piezoelectric element 21 arranged so that the displacement direction of the piezoelectric element 21 is parallel to the axis of the flexspline 3, but also the displacement direction of the piezoelectric element 21 is the axis of the flexspline 3. Can be arranged so as to form a fixed angle with respect to. In this case, one or more displacement direction changing means 8 shown in FIG. 6 (a) or (b) is used so that the displacement direction of the piezoelectric element 21 is in the direction of the fixed end 40a.

[Example v]

FIGS. 10 (a) and 10 (b) show an embodiment of the wave gear device 1 provided with the wave generator 4 including the displacement generating means 6, the displacement amplifying means 7 and the displacement direction changing means 8. . FIG. 2A is a cross-sectional view taken along a plane passing through the axis of the flexspline 3, and FIG. 1B is a cross-sectional view taken along line XX of FIG.

The displacement generating means 6 includes eight piezoelectric elements 21 and the piezoelectric elements 21.
And a piezoelectric element driving device (not shown) for sequentially selecting and energizing 21. As shown in FIG. 10 (b), the displacement direction of the piezoelectric element 21 of the displacement generating means 6 is
Are arranged at substantially equal intervals on the circumference so as to be in a connecting direction of a circle centered on the axis on a plane perpendicular to the axis. The piezoelectric element 21 in the present embodiment is of a type that gives displacement in both directions.

The displacement amplifying means 7 is composed of a member having a portion 31 that comes into contact with the piezoelectric element 21 and two displacement amplifying mechanisms 32a and 32b. The displacement amplifying mechanisms 32a and 32b are the same as those shown in FIG.

The displacement direction changing means 8 includes an elastic member 40. Both ends 40a and 40b of the elastic member 40 are connected to portions 53 of the displacement amplifying mechanisms 32a and 32b that transmit the amplified displacement. The direction of the displacement transmitted by the portion 53 transmitting the amplified displacement is the direction of the other end. When the displacement is transmitted from the portion 53 that transmits the amplified displacement of the displacement amplification mechanism 32a, 32b to both ends 40a, 40b of the elastic member 40 in the direction toward the other end, the elastic member 40 has the circular ends with both ends 40a, 40b as both ends. It bends in an arc shape so as to be convex in the direction of the spline 2. As described above, the displacement generated in the horizontal direction in the figure from the displacement generating means 6 is changed in the vertical direction in the figure at the portion in contact with the inner surface of the flexspline 3.

The wave generator 4 is provided with a fixing portion 54 between two points 52 acting as fulcrums, and the wave generator 4 is fixed at the fixing portion 54 via a fixing member 55.

The wave gear device 1 having the above configuration operates as follows. When the piezoelectric element 21 is displaced in both tangential directions, the displacement is amplified by the two displacement amplifying mechanisms 32a and 32b. Further, the direction of displacement is changed by the elastic member 40. The amplified displacement is transmitted to the inner surface of the flexspline 3, and the flexspline 3 is bent in a non-circular shape. For this reason, the position where the flexspline 3 and the circular spline 2 mesh with each other is moved by sequentially urging the piezoelectric elements 21, for example, clockwise by the piezoelectric element driving device, so that the output can be taken out from the output shaft 5.

In the above embodiment, the flex spline 3 is an external gear, and the circular spline 2 is a wave gear device in the form of an internal gear.
Can be formed as an internal gear and the circular spline 2 as an external gear to form a wave gear device.

An embodiment of a wave gear device in which the flexspline 3 is formed as an internal gear and the circular spline 2 is formed as an external gear will be described.
11 (a) and (b). A set of energized piezoelectric elements
Except that the axis connecting 21 is a short axis, the configuration is the same as that of the wave gear device shown in the above embodiment, and the same operation can be obtained.

The scope of the present invention is not limited to the above embodiments, and various changes can be made within the scope of the invention described in the claims, which are also included in the scope of the present invention. It is.

For example, in the embodiment I, the displacement direction of the piezoelectric element 21 is not limited to the axial direction of the flexspline 3 but may be the opposite direction. It is sufficient if the piezoelectric element 21 is perpendicular to the flexspline 3 axis. Similarly, the piezoelectric element in Example II
The displacement direction of the flexspline 3 is not limited to the direction toward the closed end of the flexspline 3, but may be the opposite direction. It is sufficient if it is parallel to the axis of the flexspline 3.

Further, the piezoelectric element 21 can be disposed inside or outside the flexspline 3, and the distance from the flexspline 3 does not matter.

Further, when the direction of displacement given by the piezoelectric element 21 is perpendicular to the axis of the flexspline 3 (parallel to the axis when the elastic member 40 is used), it is not necessary to use the displacement direction changing means 8. When the direction of displacement given by 21 is not perpendicular to the axis of flexspline 3 (not parallel to the axis when elastic member 40 is used), one or more displacement direction changing means 8 is used to change the direction of displacement. The direction can be changed to a direction perpendicular to the axis (a direction parallel to the axis when the elastic member 40 is used). Therefore, the piezoelectric element 21 can be arranged in any direction.

In the above embodiment, the number of the piezoelectric elements 21 is 12 or 8, but the number of the piezoelectric elements 21 can be arbitrarily selected. However, the number of piezoelectric elements 21 is preferably a multiple of four.

The direction of displacement of the piezoelectric element 21 shown in FIGS. 10 and 11 does not necessarily need to be displaced in both the left and right directions in the figure, and the elastic member 40 can be operated even if displaced in only one of the directions.

The elastic member 40 in FIGS. 8 to 11 may be a single member, or a plurality of members may be arranged in parallel.

The piezoelectric element 21 may be of a bimorph type in addition to the unimorph type, but the unimorph type piezoelectric element is more suitable for the wave generator of the present wave gear device.

As the material of the displacement amplifying means 7 and the displacement direction changing means 8, too hard one is not deformed, and too soft one absorbs the displacement of the piezoelectric element, so that it has a certain hardness and a certain elasticity. Are preferred. The most preferable material is metal, but in addition to metal, ceramic, resin and the like can be selected as the material.

(Modification)

FIGS. 12 (a), (b) and (c) show an example of another type of wave gear device provided with a wave generator using a piezoelectric element.
FIGS. 7A and 7B are schematic views showing an operation state of the wave gear device, and FIG. 7C is a cross-sectional view taken along line XX of FIG.

The wave gear device 1 includes a circular spline 2, a flexspline 3, and a wave generator 4 which bends the flexspline 3 non-circularly and partially meshes with the circular spline 2. The wave generator 4 includes a plurality of piezoelectric elements 21 whose both ends can be displaced in a direction away from each other and a direction approaching each other, and a piezoelectric element driving device (not shown) for sequentially selecting and energizing the piezoelectric elements 21. ). The plurality of piezoelectric elements 21 are arranged at substantially equal intervals on the inner peripheral surface of the flexspline 3 so that the direction of displacement is in the circumferential direction of the flexspline 3. When the piezoelectric element 21 is displaced, the flex spline 3 is also displaced. In addition, the piezoelectric element driving device urges the piezoelectric elements 21a disposed at both ends in the diametrical direction of the flexspline 3 so as to be displaced in a direction in which the flexspline 3 is pulled (hereinafter, referred to as a “pulling direction”). The piezoelectric elements 21b arranged at both ends in the diameter direction orthogonal to the diameter direction are biased so as to be displaced in a direction for compressing the flexspline 3 (hereinafter, referred to as a "compression direction").

The wave gear device 1 having the above configuration operates as follows.

As shown in FIG. 12 (a), the piezoelectric element driving device urges the piezoelectric elements 21a arranged at both ends in the diametrical direction of the flexspline 3 so that the displacement direction becomes the tensile direction. The piezoelectric elements 21b disposed at both ends of the diameter orthogonal to the diameter at which the piezoelectric element 21a is located are also urged so that the displacement direction is the compression direction. Piezoelectric element 21
a, 21b are joined to the inner surface of the flexspline 3 so that the piezoelectric elements 21a, 21b are displaced and
Also displaces. Therefore, the flexspline 3 extends around the flexspline 3 to which the piezoelectric element 21a is joined, and the flexspline 3 to which the piezoelectric element 21b is joined.
The flexspline 3 shrinks around. By the operation of these piezoelectric elements 21a and 21b, the flexspline 3 is deformed into an elliptical shape whose short side is a diameter connecting the piezoelectric elements 21a and whose long side is a straight axis connecting the piezoelectric elements 21b. Thereafter, a diameter connecting a pair of piezoelectric elements urged to be displaced in the tensile direction,
The piezoelectric elements are sequentially moved clockwise, for example, by the piezoelectric element driving device to urge the piezoelectric elements while maintaining a relationship in which the diameters connecting the pair of piezoelectric elements urged to be displaced in the compression direction are orthogonal to each other. Thereby, the engagement position between the flexspline 3 and the circular spline 2 is as if the flexspline 3 deformed in an elliptical shape has rotated from the position shown in FIG. 12 (a) to the position shown in FIG. 12 (b). Move sequentially. As described above, by continuously energizing the piezoelectric element 21 while maintaining the above relationship, for example, if the circular spline 2 is fixed, the flexspline 3 is rotated while the flexspline 3 rotates once. Moves in the direction opposite to the biasing direction of the piezoelectric element 21 by the number of teeth smaller than that of the circular spline 2, and this movement is used as an output from the output shaft 5 connected to the flexspline 3 (see FIG. 12 (c)). Can be taken out.

 Various modifications can be made in this modification.

For example, in this modification, the wave gear device of the type in which the flex spline 3 is an external gear and the circular spline 2 is an internal gear has been described, but the present invention is not limited to this type, and the flex spline 3 is an internal gear, and the circular spline 2 is an internal gear. The same is applicable to a wave gear device of a type that is an external gear.

The number of piezoelectric elements 21 is also arbitrary, but is preferably a multiple of four.

Further, the piezoelectric element 21 may be of either a unimorph type or a bimorph type, but in this modification, a bimorph type piezoelectric element is more suitable.

〔The invention's effect〕

According to the present invention, it is possible to amplify the displacement of the piezoelectric element and sufficiently flex the flexible gear in a non-circular shape. Further, when the displacement needs to be changed during the amplification of the displacement, the change of the displacement direction is performed. It is possible to realize a wave gear device that is also possible.

[Brief description of the drawings]

FIGS. 1, 3 to 5 and FIGS. 7 to 11 (a) show a wave gear device according to an embodiment of the present invention when cut along a plane passing through the axis of a flexible gear. Sectional view,
2 (b) is a cross-sectional view taken along line XX of FIG. 2 (a), FIGS. 2 (a) and 2 (b) are schematic diagrams showing a displacement amplification mechanism of the displacement amplification means, and FIGS. 6 (a) and 6 (b). ) Is a schematic view showing a displacement direction changing means, FIGS. 12 (a) and 12 (b) are schematic sectional views of a wave gear device provided with another type of wave generator using a piezoelectric element, and FIG. ) Is a cross-sectional view taken along line XX of FIG. 1A, and FIGS. 13 and 14 are cross-sectional views of a conventional wave gear device provided with a wave generator using a piezoelectric element. [Description of Signs] 1 ... Wave gear device 2 ... Circular spline 3 ... Flex spline 4 ... Wave generator 5 ... Output shaft 6 ... Displacement generating means 7 ... Displacement amplifying means 8 ... Displacement direction change Means 9: Displacement amplification and displacement direction changing means 10: Wave gear device 11: Rigid circular internal gear 12: Flexible external gear 13: Wave generator 15: Disc 16: Piezoelectric element 17 … Piezoelectric element driving device 18 …… Output shaft 21, 21a, 21b …… Piezoelectric element 31 …… Part that comes into contact with the piezoelectric element 32, 32a, 32b, 32c, 32d …… Displacement amplifying mechanism 33 …… Flex spline tooth surface Abutting against the back surface of the elastic member 40a, 40b end portion of the elastic member 41 connecting member 51 a portion receiving displacement 52 a portion acting as a fulcrum 53 transmitting the amplified displacement Part 54: Fixed part 55: Fixed member 61: Point 62, 63: Part of displacement direction changing means 64 ...... convey fixed position 66 ...... displacing the receiving point 66 ...... displacement tip 70 ...... hinge

Claims (7)

(57) [Claims] 1. A wave gear device comprising: a circular spline, a flex spline, and a wave generator which bends the flex spline into a non-circular shape and partially meshes with the circular spline, wherein the wave generator comprises a displacement generating means; A displacement amplifying means for amplifying the displacement generated by the displacement generating means, wherein the displacement generating means has a displacement direction centered on the axis of the flexspline on a plane perpendicular to the axis of the flexspline. A plurality of piezoelectric elements radially arranged at intervals, and a piezoelectric element driving device for sequentially selecting and energizing the piezoelectric elements, wherein the displacement amplifying means, a portion in contact with the piezoelectric element,
The displacement amplifying mechanism comprises a member having at least one displacement amplifying mechanism and a portion that abuts against the back surface of the tooth surface of the flexspline. A wave transmitting gear comprising a member having a portion for transmitting the amplified displacement, wherein a distance between the portion acting as the fulcrum and the portion transmitting the amplified displacement is longer than a distance between the portion acting as the fulcrum and the portion receiving the displacement. apparatus. 2. A wave gear device comprising: a circular spline, a flexspline, and a wave generator which bends the flexspline into a non-circular shape and partially meshes with the circular spline, wherein the wave generator includes displacement generating means; A displacement amplifying means for amplifying a displacement generated by the displacement generating means, and at least one displacement direction changing means for changing a direction of the displacement generated by the displacement generating means, wherein the displacement generating means comprises: A plurality of piezoelectric elements radially arranged at equal intervals on a circumference of a circle around the axis such that the displacement direction is parallel or at an acute angle or an obtuse angle to the axis of the flexspline; A piezoelectric element driving device for sequentially selecting and energizing the elements, wherein the displacement amplifying means is in contact with the piezoelectric element;
The displacement amplifying mechanism comprises a member having at least one displacement amplifying mechanism and a portion that abuts against the back surface of the tooth surface of the flexspline. The displacement amplifying mechanism includes a portion that receives displacement, a portion that acts as a fulcrum, And a portion that acts as a fulcrum and a portion that transmits the amplified displacement is longer than a distance between the portion that acts as a fulcrum and the portion that receives the displacement. , A wave gear device comprising two members extending in two directions from one point, and comprising a member fixed so that one of the positions acts as a fulcrum. 3. A wave gear device comprising: a circular spline, a flex spline, and a wave generator that bends the flex spline into a non-circular shape and partially meshes with the circular spline, wherein the wave generator includes displacement generating means; A displacement amplifying means for amplifying a displacement generated by the displacement generating means, and a displacement direction changing means for changing a direction of the displacement generated by the displacement generating means. A plurality of piezoelectric elements radially arranged at equal intervals on a circumference of a circle centered on the axis of the flexspline so as to be parallel to the axis of the flexspline; and a piezoelectric element drive for sequentially selecting and energizing the piezoelectric elements A displacement amplifying means, a portion abutting on the piezoelectric element,
And a member having at least one displacement amplification mechanism. The displacement amplification mechanism includes a member having a portion that receives a displacement, a portion that acts as a fulcrum, and a portion that transmits the amplified displacement, and acts as a fulcrum. The distance between the portion and the portion that transmits the amplified displacement is longer than the distance between the portion that acts as a fulcrum and the portion that receives the displacement, and the displacement direction changing means has one end that reflects the amplified displacement of the displacement amplification mechanism. A wave gear device comprising an elastic member connected to a transmitting portion and having the other end fixed, wherein a direction of the displacement transmitted by the portion transmitting the amplified displacement is a direction toward the fixed other end. . 4. A wave gear device comprising: a circular spline, a flex spline, and a wave generator that bends the flex spline into a non-circular shape and partially meshes with the circular spline, wherein the wave generator includes displacement generating means; A displacement amplifying means for amplifying a displacement generated by the displacement generating means, and at least one displacement direction changing means for changing a direction of the displacement generated by the displacement generating means, wherein the displacement generating means comprises: A plurality of piezoelectric elements arranged radially at equal intervals on the circumference of a circle around the axis so that the displacement direction forms a fixed angle with respect to the axis of the flexspline; and sequentially selecting the piezoelectric elements A piezoelectric element driving device for energizing the displacement element, wherein the displacement amplifying means, a portion in contact with the piezoelectric element,
And a member having at least one displacement amplification mechanism. The displacement amplification mechanism includes a member having a portion that receives a displacement, a portion that acts as a fulcrum, and a portion that transmits the amplified displacement, and acts as a fulcrum. The distance between the portion and the portion transmitting the amplified displacement is longer than the distance between the portion acting as a fulcrum and the portion receiving the displacement, and the displacement direction changing means has two portions extending from one point in two directions, At least one member composed of a member fixed so that any one of the positions acts as a fulcrum, and one end is connected to a portion transmitting the amplified displacement of the displacement amplification mechanism, and the other end is fixed. Wherein the direction of the displacement transmitted by the portion transmitting the amplified displacement is a direction toward the fixed other end. Car equipment. 5. A wave gear device comprising: a circular spline, a flex spline, and a wave generator that bends the flex spline into a non-circular shape and partially meshes with the circular spline, wherein the wave generator includes a displacement generating means; Amplifying the displacement generated by the displacement generating means, and displacing and changing the direction of the displacement. The displacement generating means has a displacement direction parallel to the axis of the flexspline. A plurality of piezoelectric elements radially arranged at regular intervals on the circumference of a circle centered on the axis, and a piezoelectric element driving device for sequentially selecting and energizing the piezoelectric elements. The displacement direction changing means includes an elastic member having one end connected to the piezoelectric element and the other end fixed, and the direction of displacement of the piezoelectric element is different from the fixed direction. Wave gear device characterized in that it is a direction towards the. 6. A wave gear device comprising: a circular spline, a flex spline, and a wave generator which bends the flex spline into a non-circular shape and partially meshes with the circular spline, wherein the wave generator comprises a displacement generating means; At least one displacement direction changing means for changing the direction of the displacement generated by the displacement generating means, and a displacement amplification and displacement direction changing means for amplifying the displacement generated by the displacement generating means and changing the direction of the displacement. The displacement generating means, a plurality of radially arranged at equal intervals on the circumference of a circle centered on the axis of the flexspline such that the direction of displacement is at a constant angle with respect to the axis of the flexspline. A piezoelectric element and a piezoelectric element driving device for sequentially selecting and energizing the piezoelectric element, wherein the displacement direction changing means is provided in two directions from one point. A displacement amplification / displacement direction changing means having one end connected to the piezoelectric element and the other end fixed; A wave gear device comprising an elastic member set forth above, and a direction of displacement of the piezoelectric element is a direction toward the fixed other end. 7. A wave gear device comprising: a circular spline, a flex spline, and a wave generator which bends the flex spline into a non-circular shape and partially meshes with the circular spline, wherein the wave generator includes a displacement generating means; A displacement amplifying means for amplifying a displacement generated by the displacement generating means, and a displacement direction changing means for changing a direction of the displacement generated by the displacement generating means, wherein the displacement generating means has a displacement direction, A plurality of piezoelectric elements arranged at equal intervals on the circumference of the flexspline so as to be tangential to the circle centered on the flexspline axis on a plane perpendicular to the axis of the flexspline; and A piezoelectric element driving device for sequentially selecting and energizing, the displacement amplifying means, a portion contacting the piezoelectric element,
A displacement amplifying mechanism, wherein the displacement amplifying mechanism comprises a member having a portion that receives a displacement, a portion that acts as a fulcrum, and a portion that transmits the amplified displacement, and a portion that acts as a fulcrum and an amplifying portion. The distance between the portion transmitting the applied displacement is longer than the distance between the portion acting as a fulcrum and the portion receiving the displacement, and the displacement direction changing means includes a portion having both ends transmitting the amplified displacement of the displacement amplification mechanism. A wave gear device comprising a connected elastic member, wherein directions of displacement transmitted by the portions transmitting the amplified displacement are directions toward each other.