JPH05215193A - Reduction gear having rotation output of two degrees of freedom - Google Patents

Abstract

PURPOSE:To provide a reduction gear capable of obtaining a rotation output of different reduction gear ratio from one of two output members while the other is stopped with respect to a fixing side member by providing two harmonic reduction gears of the same speed ratio and switching a clutch mechanism. CONSTITUTION:At an end of an input shaft 2, single and double gear type harmonic reduction gears 3, 4 are coaxially disposed in an adjacent manner. An output member 5 of two degrees of freedom is disposed adjacently to the outer end face of the double harmonic reduction gear 4. On the outer periphery of both the harmonic reduction gears 3, 4 and the output member 5, an output member 6 of one degree of freedom is coaxially disposed. The harmonic reduction gears 3, 4 are respectively provided with two rigid internal gears 31, 32 and 41, 42 and annular flexible gears 33 disposed therein. They are further provided with a wave generator 34 fixed to the input shaft 2 and a wave generator 44 fixed to the input shaft 2 through a dog clutch 10. Each of the wave generators 34, 44 is formed in an elliptical shape so as to bend a flexible external gear and partly mesh with each of the rigid internal gears.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speed reducer composed of a harmonic speed reducer, and more particularly to a speed reducer capable of obtaining a rotation output having two degrees of freedom for one rotation input.

[0002]

2. Description of the Related Art Speed reducers having various structures are known. Generally, these speed reducers are configured to obtain one rotation output having a certain reduction ratio with respect to one rotation input.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to realize a speed reducer capable of obtaining a rotation output having two degrees of freedom with respect to one rotation input by using a gear type harmonic speed reducer. is there.

[0004]

In order to solve the above-mentioned problems, the speed reducer of the present invention comprises a first-stage harmonic reducer and a second-stage harmonic reducer having the same speed ratio. By assembling as described above, a rotation output with two degrees of freedom is obtained.

First, the harmonic reduction gear used in the present invention includes an annular first and second rigid internal gear, an annular flexible external gear arranged inside of these, respectively, and this external gear. Mounted on the inner side of the outer ring gear by bending the outer gear in the radial direction to partially mesh with each of the first and second rigid inner gears and moving the meshing position in the circumferential direction. , A structure provided with a wave generator for generating relative rotation between the second rigid internal gear and the flexible external gear.

In the present invention, the wave generator in the first-stage harmonic speed reducer is connected to the input shaft through the clutch mechanism so that the wave generator can be switched between a state in which it integrally rotates with the input shaft and a state in which it does not rotate. The wave generator in the second-stage harmonic speed reducer is fixed so as to rotate integrally with the input shaft. Further, the first rigid internal gear in the first-stage harmonic reduction gear is fixed so as not to rotate, and the first rotation output member integrally rotates with the first rigid internal gear in the second-stage harmonic reduction gear. It is fixed so that Furthermore, the second rotation output member is fixed to the second rigid internal gear in each of the first-stage and second-stage harmonic reduction gears so as to rotate integrally.

[0007]

When the wave generator in the first-stage harmonic reducer is set to the fixed state by the clutch mechanism, the first-stage harmonic reducer is not driven. Therefore, the second rigid internal gear of the first-stage harmonic reduction gear is held in a fixed state, and the second rotation output member fixed here is held in a stopped state. On the other hand, on the side of the second stage harmonic reducer, the wave generator is rotated by the input shaft, so
The rigid internal gear of rotates deceleratingly. Therefore, the first rotation output member fixed here rotates at the number of rotations reduced by the speed ratio of the second stage harmonic reduction gear.

Next, by switching the clutch mechanism and coupling the wave generator in the first-stage harmonic reducer to the input shaft, both the first-stage and second-stage harmonic reducers are driven. Therefore, the first rotation output member fixed to the second rigid internal gear of the first-stage harmonic reduction gear rotates at a rotation speed reduced at the speed ratio of the first-stage harmonic reduction gear. Here, in the second-stage harmonic speed reducer, the second
The rigid internal gear is rotated by the deceleration rotation output of the first-stage harmonic reduction gear. Therefore, the first rigid internal gear of the second-stage harmonic reduction gear is apparently held in a stopped state with respect to the stationary member.

As described above, in the speed reducer of the present invention, the first and second rotation output members apparently make independent rotational movements with respect to one input, and do not affect each other's operation. Perform different deceleration rotation.

[0010]

Embodiments of the present invention will be described below with reference to FIGS.

First, the overall structure of the speed reducer of this embodiment will be described with reference to FIG. The speed reducer 1 of this example has an input shaft 2
And the first-stage and second-stage gear-type harmonic reducers 3 and 4 arranged coaxially adjacent to the tip end portion thereof, and the two freedoms arranged adjacent to the outer end face side of the second-stage side harmonic reducer 4. The degree output member 5 (first rotation output member) and the harmonic reducers 3 and 4 and the output member 5 are coaxially arranged on the outer periphery of the output member 5.
It has a degree-of-freedom output member 6 (second rotation output member).

The first stage harmonic reducer 3 has a ring-shaped first
Rigid internal gear (S-side internal gear) 31 and second rigid internal gear (D-side internal gear) 32, annular flexible external gear 33 arranged inside these, and mounted inside this It is composed of an elliptical wave generator 34. The first rigid internal gear (S) 31 has the same number of teeth as the external gear 33, but the second rigid internal gear (D) 32 has 2 more teeth than the external gear 33.
It has a large number of teeth. The wave generator 34 includes an elliptical rigid cam plate 34a and a ball bearing 34b fitted on the outer periphery thereof. Wave generator 3
4, the flexible external gear 33 is bent into an elliptical shape, and meshes with the first and second rigid internal gears 31 and 32 at two positions on both ends of the elliptical major axis, respectively. FIG. 1 shows a cross-sectional position including the long axis.

The wave generator 34 in the first stage harmonic reducer 3 is rotatably supported on the outer periphery of the input shaft 2 via a bearing 7. Further, the first rigid internal gear (S) 31 is fixed to the case (fixed side member) 1 a of the device 1. On the other hand, the second rigid internal gear (D) 3
A two-degree-of-freedom output member 6 is fixed to the two so as to rotate integrally.

The second-stage harmonic reducer 4 is also a reducer having the same structure and size as the first-stage harmonic reducer 3 having the same speed ratio. However, they differ in the following points. First, the wave generator 44 is fixed to the input shaft 2 and always rotates integrally with the input shaft 2. Next, the first rigid internal gear (S
Side internal gear) 41 and second rigid internal gear (D side internal gear) 42
Is the first and second rigid internal gears 31 in the first stage,
32 and the second rigid internal gear (D) 42 are arranged in a mirror image relationship with the second gear 32.
Of the rigid internal gear (D) 32. Further, the one-degree-of-freedom output member 6 is fixed to the second rigid internal gear (D) 42 so as to rotate integrally.
On the other hand, the two-degree-of-freedom output member 5 is fixed to the outer end surface of the first rigid internal gear (S) 41 so as to rotate integrally.

The two-degree-of-freedom output member 5 is a disc-shaped shaft member having a large diameter on the base end side, and the back-side end face of the disc-shaped portion is the second rigid first internal gear ( S) 41 is fixed to the annular end surface. On the other hand, the one-degree-of-freedom output member 6
Has a cylindrical shape as a whole, and its inner peripheral surface on the base end side is rotatably supported on the case 1a side via a ball bearing 8. Further, the inner peripheral surface on the tip end side thereof is also provided with the ball bearing 9 and the disk-shaped portion of the two-degree-of-freedom output member 5 and the first rigid internal gear (S) 41.
It is rotatably supported with respect to the outer circumference. Further, an annular protrusion 61 protruding inward is formed at a position in the middle of the inner peripheral surface of the cylindrical one-degree-of-freedom output member 6, and here, the first and second stages are formed. The second rigid internal gear (D) 32, 42 is fixed.

Here, the first-stage wave generator 34 can be switched between a state in which it integrally rotates with the input shaft 2 and a state in which it is separated from the input shaft and fixed to the case 1a side. The dog clutch mechanism 10 is incorporated between the wave generator 34 and the device case 1 a and the input shaft 2. The dock clutch mechanism 10 has a first position (a position shown by a solid line in the drawing) away from the wave generator 34 and a second position (a position close to the wave generator 34) in the axial direction of the input shaft 2. An engaging member 11 which is slidable between a position (shown by a dotted line in the drawing), an engaging groove 12 on the side of the wave generator 34 with which the engaging member 11 is constantly engaged,
The engagement protrusion 13 fixed to the outer periphery of the input shaft 2 so that the engagement member 11 engages only when the engagement member 11 is located at the second position indicated by the dotted line, and the above engagement member. It is composed of a mechanism (not shown) for sliding 11.

Next, the deceleration operation of the thus constructed deceleration device 1 of the present embodiment will be described.

First, as shown in FIG. 2, when the engagement member 11 of the dog clutch mechanism 10 is set to the first position, the first-stage wave generator 34 is disconnected from the input shaft 2. It is fixed to the case (fixed member) 1a side. Therefore, the first-stage harmonic reduction gear 3 does not operate, and the one-degree-of-freedom output member 6 fixed to the second rigid internal gear (D) 32 and the second rigid internal gear on the second-stage side. (D) 42 is in a stopped state without rotating. Therefore, the second-stage harmonic reduction gear 4 operates in the same manner as a single harmonic reduction gear to which the second rigid internal gear (D) 42 is fixed, and the first rigid internal gear (S). The decelerated rotation is output from the side of 41. That is, only the two-degree-of-freedom output member 5 fixed here rotates at reduced speed. At this time, the reduction ratio i is expressed by the following equation.

I = 1 / (R + 1) (1) where R is a speed ratio.

Next, as shown in FIG. 3, when the engagement member 11 of the dog clutch mechanism 10 is set to the second position, the first-stage wave generator 34 is fixed to the input shaft 2. ,
It rotates together with this. The harmonic reduction gear 4 on the second stage side also rotates integrally with the input shaft 2. Therefore, both harmonic reduction gears 3 and 4 operate simultaneously.

Since the first rigid internal gear (S) 31 of the first-stage harmonic reduction gear 3 is fixed, decelerated rotation is output from the second rigid internal gear (D) 32 of the first harmonic internal gear (S) 31. The fixed one-degree-of-freedom output member 6 decelerates and rotates at a reduction ratio i represented by the following equation. Further, the second rigid internal gear (D) 42 on the second stage side also rotates in the same manner.

I = −1 / R (2)

In the second stage harmonic speed reducer 4, the wave generator 44 rotates in the same direction as the input shaft 2 at the same speed, and the second rigid internal gear (D) 42 moves in the opposite direction to the input shaft 2. The motor rotates at the speed reduction ratio determined by equation (2). As a result, the first rigid internal gear (S) 41 rotates in a direction and at a speed at which it is apparently stopped with respect to the case (fixed-side member) 1a. That is, the one-degree-of-freedom output member 5 fixed here does not rotate relative to the case 1a. Therefore, with respect to the case 1a side, only the two-degree-of-freedom output member 6 rotates at the speed reduction ratio obtained by the equation (2).

As described above, in the speed reducer 1 of this example, by switching the dog clutch mechanism 10, it is possible to obtain a decelerated rotation output having two degrees of freedom with respect to the case (fixed member) 1a. ..

In the speed reducer of the present embodiment, the first rigid internal gear (S), the second rigid internal gear (D), the second rigid internal gear (D) and The first rigid internal gear (S) is arranged in this order, but instead of this, the second rigid internal gear (D), the first rigid internal gear (S), the first rigid internal gear (S), and the The two rigid internal gears (D) may be arranged in this order. Further, although the dog clutch mechanism is used in the apparatus of this example, it is needless to say that the connection state of the first-stage wave generator may be switched using a switching mechanism having another structure. Furthermore, in the device of this example, the most typical harmonic reducer in which a flexible external gear is meshed with a rigid internal gear at two positions by using an elliptical wave generator. Of course, a harmony reduction gear having a configuration other than that may be used.

[0026]

As described above, in the present invention, by switching the clutch mechanism, one of the two output members is held in a stopped state with respect to the fixed side member, and the other side is different. The rotation output of the reduction ratio can be obtained.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view showing a speed reducer according to an exemplary embodiment of the present invention.

FIG. 2 is a partial cross-sectional view for explaining the operation of the reduction gear transmission of FIG.

FIG. 3 is a partial cross-sectional view for explaining the operation of the speed reducer of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Reduction gear 2 ... Input shaft 3 ... Harmonic reducer of 1st stage 4 ... Harmonic reducer of 2nd stage 5 ... 2 degree-of-freedom output member (1st rotation output member ) 6 ... 1 degree of freedom output member (second rotation output member) 7, 8, 9 ... Ball bearing 10 ... Dog clutch mechanism

Claims (5)

[Claims] 1. A first-stage harmonic reducer and a second-stage harmonic reducer having the same speed ratio as that of the first-stage harmonic reducer. These harmonic reducers each have an annular first and second rigidity. An internal gear, a ring-shaped flexible external gear arranged inside these, and an external gear mounted inside the external gear and flexing the external gear in the radial direction of the first and second rigid internal gears. Partial meshing with each other and moving these meshing positions in the circumferential direction allow relative rotation between any one of the first and second rigid internal gears and the flexible external gear. The wave generator in the first-stage harmonic speed reducer is provided with a clutch mechanism so that the wave generator can be switched between a state in which the input shaft rotates integrally and a state in which the input shaft does not rotate. It is connected to the input shaft, The wave generator in the speed reducer is fixed so as to rotate integrally with the input shaft, the first rigid internal gear in the first-stage harmony reducer is fixed so as not to rotate, and the second-stage harmony is fixed. A first rotation output member is fixed to the first rigid internal gear of the reduction gear so as to rotate integrally, and a second rigid internal gear of each of the first-stage and second-stage harmonic reduction gears. A second rotation output member is fixed to the shaft so that the second rotation output member rotates integrally with the speed reduction device having a rotation output with two degrees of freedom. 2. The wave generator in the two harmonic speed reducers according to claim 1, wherein the flexible external gear is bent into an elliptical shape, and the external gear is provided at two positions on both ends of the elliptical major axis. Is meshed with a rigid internal gear, the first rigid internal gear has the same number of teeth as the external gear, and the second rigid internal gear has 2n sheets (n is a positive number) more than the external gear. (Integer) A reduction gear having a rotation output of two degrees of freedom, which has a large number of teeth. 3. The wave generator in the two harmonic reduction gears according to claim 1, wherein the flexible external gear is bent into an elliptical shape, and the external gear portion is provided at two positions at both ends of the elliptical major axis. Is meshed with a rigid internal gear, the second rigid internal gear has the same number of teeth as the external gear, and the first rigid internal gear has 2n sheets (n is a positive number) more than the external gear. (Integer) A reduction gear having a rotation output of two degrees of freedom, which has a large number of teeth. 4. The harmonic reducer according to claim 1, wherein the two harmonic reducers are arranged adjacent to each other coaxially with respect to the input shaft. The first rotation output member is disposed adjacent to the outer end surface side of the, and the annular second rotation output member is coaxial with the outer periphery of the harmonic reduction gear and the first rotation output member. A speed reducer having a rotation output of two degrees of freedom, which is arranged in a state. 5. The clutch mechanism according to claim 4, wherein the clutch mechanism is a dog clutch mechanism that is slidable between a first position and a second position in the axial direction of the input shaft. The wave generator of the eye harmonic reducer is coupled to the side of the fixing member so as not to rotate, and
The speed reducer having a rotation output of two degrees of freedom, wherein the wave front generator is coupled to the input shaft so that the wave front generator rotates integrally with the input shaft at the position.