JP7412739B2 - Wave gear device - Google Patents

Description

The present invention relates to a wave gear device.

For example, in a robot whose arms move via joints, the rotation of a motor built into a given arm is decelerated by a reducer, and the decelerated output drives an arm connected to that arm to rotate. ing. As this type of speed reducer, one using a wave gear device is known.

Patent Document 1 describes an annular circular spline (rigid internal gear), a thin cup-shaped flexspline (flexible external gear) located on the inner peripheral side, and a circular spline (flexible external gear) fitted on the inner peripheral side. A wave gear device is disclosed that includes a wave generator having an elliptical cam. The flex spline is bent into an elliptical shape by the cam of the wave generator and is partially meshed with the circular spline. When the cam of the wave generator rotates in response to rotation input from a motor, etc., the meshing position of both gears moves in the circumferential direction, and a relative rotational movement is created between the two gears according to the difference in the number of teeth between the two gears. Occur. The wave gear device according to Patent Document 1 is configured to obtain a deceleration rotational output from a flexspline, and specifically has a structure in which an output shaft is attached to a diaphragm that forms the bottom of the flexspline.

JP2012-72912A

First, the wave gear device according to Patent Document 1 has a problem in that the flex spline is easily damaged due to its structure. This is due to the following reason. Here, consider a plurality of virtual points arranged in the circumferential direction around the rotation axis (hereinafter referred to as the axis) of the output shaft as points for transmitting force from the rotating flexspline to the output shaft. Due to the flexibility of the rotating flexspline and the elliptical shape of the cam, the vector of force applied to each virtual point from the rotating flexspline does not point uniformly in the circumferential direction, and the phase varies depending on the point. A shift occurs. In the flexspline disclosed in Patent Document 1, the output shaft is fixed to a diaphragm that closes one end of the cylindrical portion, so that the flexspline has a structure in which rotational force is transmitted to the output shaft over the entire circumference of the cylindrical portion, and the above-mentioned This results in a state that includes many force vectors that have phase shifts. This generates unnecessary stress in the cylindrical portion of the flexspline that does not contribute to the torque for rotating the output shaft about the rotation axis, and unnecessary twisting force is applied. In addition to this unnecessary twisting force being applied, flexsplines have the problem of being easily damaged because their cylindrical portions are formed with very thin walls (for example, the wall thickness is about 0.1 mm). be.

In addition, the flexspline according to Patent Document 1 has a structure in which the output shaft is fixed to a diaphragm that closes one end of the cylindrical part, so that the position of the output shaft is changed by the height of the cylindrical part (length along the axis). It moves away from the rotating body on the side (for example, the cam of a wave generator). For this reason, there is also the problem that the wave gear device tends to become larger in the direction along the axis.

SUMMARY OF THE INVENTION An object of the present invention is to provide a wave gear device that is less likely to be damaged and can suppress the increase in size of the device.

In order to achieve the above object, the wave gear device according to the first aspect of the present invention includes:
an internal gear portion having an inner gear formed along the inner peripheral surface;
a wave generating section having a cam section that rotates around an axis in response to a rotational input;
a ring-shaped outer gear formed along an outer circumferential surface with a smaller number of teeth than the inner gear, the inner circumferential side of which is fitted into the wave generation section; and a flex having an adjacent section adjacent to the outer gear in a direction along the axis. The gear part and
an output shaft portion having a facing portion facing the adjacent portion in a radial direction centered on the axis, and rotating with the flex gear portion relative to the internal gear portion;
a transmission part fixed to the opposing part, extending toward the adjacent part, and transmitting power of the flex gear part to the output shaft part,
The cam portion has N (N is an integer of 2 or more) pole portions located at equal intervals in a circumferential direction centered on the axis, and meshes the outer gear with the inner gear at N locations,
The adjacent portion is provided with an inserted portion into which the transmission portion is inserted and which allows relative displacement between the flex gear portion and the output shaft portion in the circumferential direction;
The pair of the transmitting part and the inserted part ,
There are eight or more , arranged in the circumferential direction ,
When the cam portion rotates about the axis, the transmission portion is located at one end of the inserted portion in the circumferential direction; and a second pair located at the other end in the circumferential direction.

In order to achieve the above object, a wave gear device according to a second aspect of the present invention includes:
an internal gear portion having an inner gear formed along the inner peripheral surface;
a wave generating section having a cam section that rotates around an axis in response to a rotational input;
a ring-shaped outer gear formed along an outer circumferential surface with a smaller number of teeth than the inner gear, the inner circumferential side of which is fitted into the wave generation section; and a flex having an adjacent section adjacent to the outer gear in a direction along the axis. The gear part and
an output shaft portion having a facing portion facing the adjacent portion in a radial direction centered on the axis, and rotating with the flex gear portion relative to the internal gear portion;
a transmission part fixed to the adjacent part, extending toward the opposing part, and transmitting power of the flex gear part to the output shaft part,
The cam portion has N (N is an integer of 2 or more) pole portions located at equal intervals in a circumferential direction centered on the axis, and meshes the outer gear with the inner gear at N locations,
The opposing portion is provided with an inserted portion into which the transmission portion is inserted and which allows relative displacement between the flex gear portion and the output shaft portion in the circumferential direction;
The pair of the transmitting part and the inserted part ,
There are eight or more , arranged in the circumferential direction ,
When the cam portion rotates about the axis, the transmission portion is located at one end of the inserted portion in the circumferential direction; and a second pair located at the other end in the circumferential direction.

According to the present invention, it is difficult to break and it is possible to suppress the increase in size of the device.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an external view of a robot incorporating a wave gear device according to an embodiment of the present invention. FIG. 2 is a configuration diagram including a schematic cross section of the main components of the strain wave gear device according to the embodiment. (a) is a diagram of the main configuration of the strain wave gear device according to the above embodiment viewed from the axial direction, and is a diagram showing a case where the number of poles of the cam part is 2, and (b) is a diagram of FIG. It is a figure which shows a part of outer peripheral surface of the flex gear part of (a). It is a figure for demonstrating the arrangement|positioning and the function of the transmission part with which the wave gear device based on embodiment same as the above is provided. (a) to (d) are principle diagrams for explaining the deceleration operation of the strain wave gear device according to the above embodiment. FIG. 4 is a diagram of the cam part and the flex gear part viewed from the axial direction, where (a) shows the case where the number of poles of the cam part is 3, and (b) shows the case where the number of poles of the cam part is 4. FIG. FIG. 3 is a diagram of the cam part and the flex gear part viewed from the axial direction, where (a) shows the case where the number of poles of the cam part is 5, and (b) shows the case where the number of poles of the cam part is 6. FIG. FIG. 3 is a view of the cam part and the flex gear part viewed from the axial direction, where (a) shows the case where the number of poles of the cam part is 7, and (b) shows the case where the number of poles of the cam part is 8. FIG. (a) is a schematic cross-sectional view of the main components of the wave gear device according to the embodiment, and (b) is a schematic cross-sectional view of the main components of the wave gear device according to the conventional example. It is a figure which shows the modification 1 which modified the partial structure of the wave gear device based on embodiment same as the above. (a) is a diagram showing a modification 2 in which a partial configuration of the strain wave gear device according to the above embodiment is modified, and (b) is a diagram showing a modification in which a partial configuration of the strain wave gear device according to the embodiment same as the above is modified. FIG. 7 is a diagram showing Example 3.

An embodiment of the present invention will be described with reference to the drawings.

The strain wave gear device 100 according to this embodiment is incorporated into an industrial robot 200, as shown in FIG. The robot 200 is, for example, a vertically articulated robot, and includes a robot main body 210 installed on a base 201 and a controller 220 that drives and controls the robot main body 210. The robot main body 210 includes a first arm 211, a second arm 212 connected to the first arm 211 via the wave gear device 100, and a motor 213 shown in FIG. The motor 213 is composed of a servo motor or the like, and operates under the control of the controller 220. The controller 220 rotates the second arm portion 212 via the motor 213 built into the first arm 211 and the wave gear device 100, thereby controlling the positioning, angle control, and angle of the second arm 212 relative to the first arm 211. Performs rotation speed control.

As shown in FIG. 2, the wave gear device 100 includes a wave generation section 10, a flex gear section 20, an internal gear section 30, an output shaft section 40, a support section 50, and a transmission section T.

Note that in FIG. 2, hatching showing cross sections of some components is omitted for ease of viewing, and the first arm 211 and the second arm 212 are shown with imaginary lines. Furthermore, hereinafter, when describing the configuration of the wave gear device 100, the right side in FIG. 2 may be referred to as an input side (Si in the drawing), and the left side may be referred to as an output side (So in the drawing). The same applies to FIG. 9, which will be described later.

The wave generating section 10 includes a cylindrical shaft section 11 , a cam section 12 formed integrally with the cylindrical shaft section 11 , and a wave bearing 13 .

The cylindrical shaft portion 11 has an input side end rotatably supported by a bearing B1, and an output side end rotatably supported by a bearing B2. The bearing B1 is provided on a stationary portion 211a that is stationary with respect to the first arm 211. The bearing B2 is provided on the inner peripheral surface of the output shaft portion 40. The bearings B1 and B2 are composed of, for example, ball bearings. Thereby, the cylindrical shaft portion 11 is rotatably supported by the first arm 211 around the axis AX. The rotational power of the motor 213 is transmitted to the cylindrical shaft portion 11 via a known transmission mechanism. This transmission mechanism may be a gear mechanism, a belt mechanism using a timing belt and a pulley, or the like.

The cam portion 12 is provided to protrude from the outer peripheral surface of the cylindrical shaft portion 11 in the outer radial direction. The cam portion 12 is provided at a position adjacent to the bearing B1 in the direction along the axis AX (hereinafter also referred to as the "axial direction"). The cam portion 12 has N (N is an integer of 2 or more) pole portions located at equal intervals in the circumferential direction around the axis AX. Below, the number of pole parts that the cam part 12 has will be referred to as the number of poles. For example, when the number of poles is N=2, the cam portion 12 has an elliptical shape when viewed from the axial direction, as shown in FIG. 3(a).

As shown in FIGS. 2 and 3(a), the wave bearing 13 has an inner ring 13i fixed to the outer peripheral surface of the cam part 12, a flexible outer ring 13o, and a rotatable ring between the inner ring 13i and the outer ring 13o. A plurality of balls 13b are inserted in the state. Note that the inner ring 13i may be configured from a portion including the outer circumferential surface of the cam portion 12.

The flex gear portion 20 is made of a metal material such as special steel and has flexibility, and is formed, for example, in a cylindrical shape along the axial direction. The flex gear section 20 includes an outer gear 21 and an adjacent section 22 formed integrally with the outer gear 21.

The outer gear 21 is formed into a ring shape with a predetermined number t of teeth 21a formed along the outer circumferential surface, and the inner circumferential side is fitted into the outer ring 13o of the wave generating section 10. The plurality of teeth 21a in the outer gear 21 are arranged along the circumferential direction at a constant pitch. The number t of teeth of the outer gear 21 is set to be smaller than the number Ti of teeth of the inner gear 31, which will be described later. For example, when the number of poles of the cam portion 12 is N, the relationship between the number of teeth t and the number of teeth Ti is set so that "Ti=t+N" holds true. For example, when N=2, the relationship "Ti=t+2" holds true.

The adjacent portion 22 is a portion adjacent to the outer gear 21 in the axial direction and protrudes from the outer gear 21 toward the output side. The adjacent portion 22 is provided with an inserted portion H into which the transmission portion T is inserted, as shown in FIGS. 3(a) and 3(b). The power of the flex gear section 20 is transmitted to the output shaft section 40 via the transmission section T inserted into the inserted section H. The inserted portions H are provided in the same number as the transmission portions T, and are provided in plurality along the circumferential direction centered on the axis AX. The transmitting portion T and the inserted portion H will be described in detail later.

Note that in FIGS. 3A and 3B, the adjacent portion 22 of the flex gear portion 20 is partially shown. Further, FIG. 3(b) is a diagram of a part of the outer circumferential surface of the flex gear portion 20 viewed from the 0° direction shown in FIG. 3(a).

Further, the shape of the adjacent portion 22 is arbitrary, and the entire circumference may be in a ring shape protruding from the outer gear 21, or each portion where the inserted portion H is provided may protrude from the outer gear 21 toward the output side. It's okay. Although not shown, a portion recessed toward the outer circumferential side is provided on the inner circumferential surface of the flex gear portion 20 at a position corresponding to between adjacent teeth among the plurality of teeth 21a formed on the outer gear 21, The flex gear portion 20 may be made easily flexible.

The internal gear part 30 is a part that is rigidly formed of a metal material, is fixed inside the first arm 211, and is partially connected to the outer gear 21 of the flex gear part 20 bent by the cam part 12. It has an inner gear 31 that meshes with it.

The inner gear 31 is formed into a ring shape and has teeth 31a having a predetermined number of teeth Ti (Ti>t) formed along the inner peripheral surface. The plurality of teeth 31a in the inner gear 31 are arranged along the circumferential direction at a constant pitch.

The output shaft section 40 rotates with respect to the internal gear section 30 together with the flex gear section 20. The output shaft section 40 is supported by a support section 50 so as to be rotatable around the axis AX with respect to the internal gear section 30. The output shaft portion 40 is made of, for example, a metal material, and has rigidity and is formed into a ring shape. The output shaft portion 40 has a facing portion 41 that faces the adjacent portion 22 of the flex gear portion 20 in a radial direction (hereinafter also simply referred to as “radial direction”) centered on the axis AX, and a portion on the output side of the facing portion 41. and a supported portion 42 which is a portion supported by the support portion 50. A fixing hole 41 a for fixing the transmission section T to the output shaft section 40 is formed in the opposing section 41 . As shown in FIG. 2, the opposing portion 41 of the output shaft portion 40 is located on the inner peripheral side of the adjacent portion 22 of the flex gear portion 20. As shown in FIG.

The support part 50 is made of, for example, a cross roller bearing, and has an outer ring 51 fixed to the internal gear part 30 and an inner ring 52 fixed to the supported part 42 of the output shaft part 40. Thereby, the support part 50 supports the output shaft part 40 rotatably around the axis AX with respect to the internal gear part 30.

In this embodiment, the output shaft portion 40 is connected to the second arm 212, which is a load of the wave gear device 100, via the inner ring 52 of the support portion 50. Thereby, as the output shaft portion 40 rotates, the second arm 212 rotates around the axis AX. Note that the manner in which the output shaft portion 40 is supported by the support portion 50 is arbitrary, and for example, the inner circumferential surface of the inner ring 52 of the support portion 50 may be fixed to the output shaft portion 40. Furthermore, the connection method between the output shaft section 40 and the load (in this example, the second arm 212) may be arbitrary. For example, the load may be connected to a disk-shaped plate fixed to the output shaft section 40. It's okay.

As shown in FIG. 2, the adjacent portion 22 of the flex gear portion 20 and the opposing portion 41 of the output shaft portion 40 are located between the support portion 50 and the cam portion 12 in the axial direction. By pushing the transmission part T fixed to the output shaft part 40 by the flex gear part 20 in the circumferential direction (hereinafter also simply referred to as the "circumferential direction") around the axis AX, the output shaft part 40 , rotates together with the flex gear section 20.

The transmission section T transmits the power of the flex gear section 20 to the output shaft section 40, and is fixed to the opposing section 41 of the output shaft section 40. The transmission part T is formed of a cylindrical pin, for example, and is inserted into the fixing hole 41a of the opposing part 41, and is fixed by a known fixing method such as screwing, fitting, fixing, welding, or the like. The transmission portion T extends along the radial direction centered on the axis AX, toward the adjacent portion 22 of the flex gear portion 20, and is inserted into the inserted portion H provided in the adjacent portion 22.

As shown in FIGS. 3(a) and 3(b), the inserted portion H is inserted with the transmission portion T, and has a diameter in the circumferential direction (C in the drawing) that is equal to the outer diameter ( It consists of a long hole that is longer than the diameter. As a result, the inserted part H is caused by the relative displacement between the flex gear part 20 and the transmission part T in the circumferential direction (that is, the relative displacement between the flex gear part 20 and the output shaft part 40 in the circumferential direction). is allowed. Further, the elongated hole serving as the inserted portion H is a through hole that penetrates the adjacent portion 22 in the radial direction centered on the axis AX. Therefore, the inserted part H also allows relative displacement between the flex gear part 20 and the transmission part T in the radial direction (that is, relative displacement between the flex gear part 20 and the output shaft part 40 in the radial direction). . The length of the inserted portion H in the circumferential direction may be set so that a first pair and a second pair, which will be described later, can appear as a pair of the transmission portion T and the inserted portion H. In addition, the width of the inserted part H in the axial direction is slightly larger than the outer diameter of the pin constituting the transmission part T, so that the movement of the transmission part T in the circumferential direction and the radial direction within the inserted part H is not hindered. Any size is fine. As shown in FIG. 4, a plurality of pairs of transmitting portions T and inserted portions H are provided along the circumferential direction, and are arranged at equal intervals in the circumferential direction.

(About deceleration operation)
Next, the deceleration operation of the strain wave gear device 100 having the above configuration will be described mainly in accordance with FIGS. 5(a) to 5(d) while referring to FIGS. 1 to 3. The number N of poles of the cam portion 12 is arbitrary depending on the purpose as long as it is an integer of 2 or more, but first, a case where the cam portion 12 has an elliptical shape with N=2 will be described.

When the motor 213 operates under the control of the controller 220 of the robot 200, the rotational power of the motor 213 is transmitted to the cam section 12 of the wave generation section 10 via a transmission mechanism (not shown), and the cam section 12 is moved relatively around the axis AX. Rotate at high speed.

Here, in order to make the explanation easier to understand, the cam part 12 before the start of rotation is initialized with the long axis of the elliptical shape coinciding with the axis passing through 0° and 180°, as shown in FIG. 5(a). Assume that it is at position Cs. Note that the illustrated angle is an angle centered on the axis AX, and assumes that the 12 o'clock direction is 0° and the angle increases in a clockwise direction. Further, it is assumed that the cam portion 12 rotates clockwise.

As shown in FIG. 5(a), the cam part 12 at the initial position Cs is at two meshing positions E of 0° and 180° corresponding to the two pole parts of the flex gear part 20 (specifically , an outer gear 21 whose reference numeral is omitted in FIG. 5) is meshed with an internal gear portion 30 (specifically, an inner gear 31 whose reference numeral is omitted in FIG. 5). In this state, it is assumed that the fixed point Xo of the internal gear section 30 is set at the 0 degree position, and the reference point Xf of the flex gear section 20 is also at the 0 degree position.

FIG. 5(b) shows a state in which the cam portion 12 has rotated 90 degrees from the initial position Cs and is at a position C1 where the major axis direction coincides with an axis passing through 90 degrees and 270 degrees.
When the cam portion 12 is displaced from the initial position Cs to the position C1, the meshing positions E of the flex gear portion 20 and the internal gear portion 30 move to positions of 90° and 270°. At this time, the number of teeth of the outer gear 21 is t, the number of teeth of the inner gear 31 is Ti = t + 2, and the difference in the number of teeth is Ti - t = 2, so the reference point Xf of the flex gear section 20 is the fixed point It rotates counterclockwise with respect to Xo by 1/2 tooth, which is 1/4 (=90°/360°) of the difference in the number of teeth "2". Letting this counterclockwise rotation angle be θ1, it is expressed as θ1={(360°/Ti)×2}/4.

FIG. 5C shows a state in which the cam portion 12 has rotated 180° from the initial position Cs and is at a position C2 where the major axis direction coincides with an axis passing through 180° and 0°.
When the cam portion 12 is displaced from the initial position Cs to the position C2, the meshing position E of the flex gear portion 20 and the internal gear portion 30 moves to the 180° and 0° positions. At this time, the reference point Xf of the flex gear section 20 is rotated counterclockwise by one tooth, which is 1/2 of the difference in the number of teeth "2" (=180°/360°), with respect to the fixed point Xo. do. Letting this counterclockwise rotation angle be θ2, it is expressed as θ2={(360°/Ti)×2}/2.

FIG. 5(d) shows a state in which the cam portion 12 has rotated 360° from the initial position Cs and is at a position C3 where the major axis direction coincides with an axis passing through 0° and 180°.
When the cam portion 12 is displaced from the initial position Cs to the position C3 (that is, rotated 360°), the meshing position E of the flex gear portion 20 and the internal gear portion 30 returns to the 0° and 180° positions. At this time, the reference point Xf of the flex gear section 20 rotates counterclockwise with respect to the fixed point Xo by the difference in the number of teeth "2". Letting this counterclockwise rotation angle be θ3, it is expressed as θ3=(360°/Ti)×2.

As described above, when the cam part 12 is rotated, the flex gear part 20 is elastically deformed, and the meshing position E with the internal gear part 30 is sequentially moved. Then, when the cam portion 12 rotates once clockwise, the flex gear portion 20 moves counterclockwise by the number of teeth 2 (=Ti−t). As a result, the output shaft section 40, which rotates together with the flex gear section 20 via the plurality of transmission sections T, is decelerated by the reduction ratio i=(Ti-t)/t with respect to the rotational speed of the cam section 12. Ru. In other words, according to the wave gear device 100, the rotation of the load (in this example, the second arm 212) connected to the output shaft portion 40 can be controlled with high precision using an output that is decelerated by the above-mentioned reduction ratio i. can. Note that the reduction ratio i is arbitrary, but is set to about 1/30 to 1/320, for example.

In the above, the case where the number of poles N is N=2 has been explained, but since the concept is the same for the case where N≧3, the explanation will be summarized here. When the number of poles is N≧3, the shape of the cam portion 12 when viewed from the axial direction is a regular N-gon shape, and, for example, each pole and between adjacent poles swell gently in the outer circumferential direction. It has a curved surface. 6 to 8 show cases where the number of poles N is 3 to 8. Although not shown, the case where N≧9 can be realized in the same way.

The outer gear 21 of the flex gear portion 20 is bent by the cam portion 12 having N pole portions via the wave bearing 13, and meshes with the inner gear 31 of the internal gear portion 30 at N locations. When the number of poles of the cam part 12 is N, the number of teeth t of the outer gear 21 (hereinafter also referred to as the number t of teeth of the flex gear part 20) and the number Ti of the inner gear 31 (hereinafter the number Ti of teeth of the internal gear part 30) ) is set so that "Ti=t+N" holds true.
For example, when the cam portion 12 rotates 360° clockwise, the flex gear portion 20 moves counterclockwise by N teeth. That is, when the number of poles of the cam part 12 is N, when the cam part 12 rotates through an angle of (360°/N), the flex gear part 20 moves by one tooth with respect to the internal gear part 30. When the number of poles of the cam part 12 is N, the output shaft part 40 fixed to the flex gear part 20 has a reduction ratio i=(Ti-t)/t=N/t with respect to the rotational speed of the cam part 12. is decelerated.

As described above, the wave gear device 100 is able to respond to the rotational input from the motor 213 regardless of whether the number of poles N of the cam portion 12 is set to N=2 or N≧3. When the cam part 12 of the wave generating part 10 rotates accordingly, the meshing position E of both the gears of the flex gear part 20 and the internal gear part 30 moves in the circumferential direction, and according to the difference in the number of teeth between the two gears. , the flex gear section 20 rotates in the opposite direction to the cam section 12 with respect to the internal gear section 30.

(About the transmission part T and inserted part H)
From here on, the transmitting section T and the inserted section H will be explained. FIG. 4 shows an example of the arrangement of the transmitting part T and the inserted part H, which is suitable when the number of poles N of the cam part 12 is N=4 (that is, the shape shown in FIG. 6(b)).

In addition, in FIG. 4, the diagram shown on the outer circumferential side of the diagram of the flex gear part 20 and the output shaft part 40 viewed from the axial direction shows that the cam part 12 with the number of poles N=4 moves along the axis according to the operation of the motor 213. A diagram showing the relative displacement of the transmitting part T and the inserted part H when the flex gear part 20 is viewed from the outer circumferential side in the range of 0° to 90° shown in the figure while rotating around AX (hereinafter referred to as It is called a relative displacement diagram.) Looking at the relative displacement diagram of FIG. 4, it can be seen that the position of the transmitting part T with respect to the inserted part H is not uniform at each position where the transmitting part T is provided. This is due to the occurrence of a phase shift as described in the above problem. The wave gear device 100 according to the present embodiment prevents unnecessary stress that does not contribute to the rotation of the output shaft portion 40 due to the above-mentioned phase shift due to the effects of the transmission portion T and the inserted portion H described below. The output shaft portion 40 is rotated with reduced transmission efficiency and good transmission efficiency.

In the example shown in FIG. 4, 16 transmission parts T arranged at equal intervals in the circumferential direction are fixed to the opposing part 41 of the output shaft part 40. Further, the adjacent portion 22 of the flex gear portion 20 is provided with 16 inserted portions H into which each of the 16 transmission portions T is inserted. That is, the pairs of the transmitting portion T and the inserted portion H are arranged in the circumferential direction every 360°/16 (=22.5°).

As shown in the relative displacement diagram in FIG. The transmitting portion located in the ° direction and the transmitting portion T located in the 90° direction are located at the center in the circumferential direction of the corresponding inserted portion H. The transmission portions T located in the 0°, 45°, and 90° directions do not contact the inserted portion H into which the transmission portion T is inserted in the circumferential direction, and therefore do not contribute to the rotation of the output shaft portion 40. .

On the other hand, in a state where a certain transmission part T is located in the 0° direction and at the center in the circumferential direction of the inserted part H corresponding to the transmission part T, the transmission located in the 22.5° direction The portion T is located at one end (clockwise end in the figure) of the inserted portion H to be inserted. Furthermore, in this state, the transmission portion T located in the 67.5° direction is located at the other end in the circumferential direction of the inserted portion H (the counterclockwise end in the figure). The transmission part T located in the 22.5° direction contacts in the circumferential direction the inserted part H of the flex gear part 20 that moves counterclockwise when the cam part 12 rotates clockwise. , contributes to the rotation of the output shaft section 40. The transmission part T located in the 67.5° direction contacts in the circumferential direction the inserted part H of the flex gear part 20 that moves clockwise when the cam part 12 rotates counterclockwise. , contributes to the rotation of the output shaft section 40.

The behavior of the transmitting part T and the inserted part H in the ranges of 90° to 180°, 180° to 270°, and 270° to 360° is the same as that of the transmitting part T and the inserted part H in the range of 45° to 90°. It is similar to the insertion section H. That is, at each position where the central angle with respect to the axis AX is 22.5 degrees, the transmission part T that contributes to the rotation of the output shaft part 40 (that is, the transmission part T that receives the force directed in the circumferential direction from the flex gear part 20) and a transmission portion T that does not contribute to rotation appear alternately. Furthermore, although the relative displacement diagram in FIG. 4 is shown statically, in the process in which the output shaft section 40 rotates by 22.5 degrees, the transmission section T that did not contribute to the rotation of the output shaft section 40 flexes. It is displaced relative to the inserted portion H into a transmission portion T that contacts the gear portion 20 in the circumferential direction and contributes to the rotation of the output shaft portion 40. On the contrary, the transmission part T that was in contact with the flex gear part 20 in the circumferential direction and contributed to the rotation of the output shaft part 40 is transferred to the transmission part T that does not contribute to the rotation of the output shaft part 40, and the inserted part H It will be displaced against.

As described above, the case where the number of poles of the cam portion 12 is N=4 and there are 16 (4×N) pairs of transmitting portions T and inserted portions H will be summarized.
When the number of poles of the cam portion 12 is N=4, when the cam portion 12 rotates by an angle of (360°/4), the flex gear portion 20 moves by one tooth with respect to the internal gear portion 30. In this way, within the range of 90°, which is the rotation angle of the cam part 12 for moving the flex gear part 20 by one tooth with respect to the internal gear part 30, the rotation angle is set at every 90°/4=22.5°. , transmission portions T that contribute to the rotation of the output shaft portion 40 and transmission portions T that do not contribute to the rotation appear alternately. The pair of the transmitting part T and the inserted part H within the range of 90 degrees is a pair in which the transmitting part T is located at one end of the inserted part H in the circumferential direction (hereinafter referred to as "first pair"). and a pair (hereinafter referred to as "second pair") in which the transmitting portion T is located at the other end in the circumferential direction of the inserted portion H. The first pair corresponds to the pair of the transmitting portion T and the inserted portion H located in the 22.5° direction in the relative displacement diagram of FIG. 4 . In addition, the second pair corresponds to the pair of the transmitting portion T and the inserted portion H located in the 67.5° direction in the relative displacement diagram of FIG. Considering this within a 360° range, there are 16 pairs of transmitting portions T and inserted portions H, 4 first pairs arranged at equal intervals in the circumferential direction, and 16 pairs of transmitting portions T and inserted portions H in the circumferential direction. and four equally spaced second pairs.

The above idea is not limited to the case where N=4, but can be generalized. Therefore, a case will be described in which the number of poles of the cam portion 12 is N (an integer of 2 or more) and there are (4×N) pairs of transmitting portions T and inserted portions H. The pairs of transmitting portions T and inserted portions H are arranged at equal intervals in the circumferential direction.
When the cam portion 12 having N poles rotates by an angle of (360°/N), the flex gear portion 20 moves with respect to the internal gear portion 30 by one tooth. In this way, within the range of (360°/N), which is the rotation angle of the cam part 12 for moving the flex gear part 20 by one tooth with respect to the internal gear part 30, the rotation angle is {360°/(4× N)}, transmission portions T that contribute to the rotation of the output shaft portion 40 and transmission portions T that do not contribute to the rotation appear alternately. The pairs of the transmitting part T and the inserted part H within the range of (360°/N) are a first pair in which the transmitting part T is located at one end in the circumferential direction of the inserted part H, and a first pair in which the transmitting part T is located at one end in the circumferential direction of the inserted part H. and a second pair located at the other end of the inserted portion H in the circumferential direction. Considering this within a 360° range, there are (4×N) pairs of transmitting portions T and inserted portions H, and N first pairs arranged at equal intervals in the circumferential direction, and N second pairs arranged at equal intervals in the circumferential direction.

As described above, if (4×N) pairs of transmitting portions T and inserted portions H are provided in the wave gear device 100, the rotation of the output shaft portion 40 is increased every {360°/(4×N)}. Transmission parts T that contribute to rotation and transmission parts T that do not contribute to rotation appear alternately. Thereby, relative displacement between the transmitting portion T and the inserted portion H in the circumferential direction can be absorbed by a so-called cam method. Therefore, according to the wave gear device 100, unnecessary stress that does not contribute to the torque for rotating the output shaft portion 40 around the axis AX is reduced from occurring in each of the flex gear portion 20 and the output shaft portion 40, and is unnecessary. This makes it possible to reduce the application of severe torsional force to the flex gear section 20.

Furthermore, when the flex gear section 20 bent by the cam section 12 rotates with respect to the internal gear section 30, the gears of the flex gear section 20 and the internal gear section 30 move while meshing with each other, so that the diameter With directional pulsations. However, since the inserted part H according to the present embodiment also allows relative displacement between the flex gear part 20 and the transmission part T in the radial direction, relative displacement between the transmission part T and the inserted part H in the radial direction is also allowed. Can be absorbed. This also makes it possible to reduce the above-mentioned unnecessary stress.

Moreover, in addition to reducing unnecessary stress, the pair of the transmitting part T and the inserted part H is arranged such that the transmitting part T is located at one end in the circumferential direction of the inserted part H, and the transmitting part T and a second pair located at the other end of the inserted portion H in the circumferential direction. Thereby, force in the circumferential direction can be efficiently transmitted from the flex gear section 20 to the output shaft section 40.

As a result, according to the wave gear device 100 of this embodiment, mechanical loss due to the connection between the flex gear section 20 and the output shaft section 40 can be significantly reduced, and good transmission efficiency can be achieved. Furthermore, damage to the flex gear section 20 can be suppressed.

In addition, since the output points (that is, the positions where the transmission part T is provided) for transmitting force from the flex gear part 20 to the output shaft part 40 can be uniformly distributed in the circumferential direction, the flex gear part 20 and the internal gear part 30 can be The load per meshing point E is reduced, and as a result, the output shaft portion 40 can be rotated with high torque.

Note that the number of pairs of the transmitting portion T and the inserted portion H is not limited to (4×N). Depending on the number N, the number of pairs of transmitting portions T and inserted portions H can be changed arbitrarily.
For example, when the number of poles N of the cam portion 12 is N=8 (that is, the shape shown in FIG. 8(b)), and the number of pairs of the transmitting portion T and the inserted portion H is (4×N)=32, Within the range of (360°/N)=45°, which is the rotation angle of the cam part 12 for moving the flex gear part 20 by one tooth with respect to the internal gear part 30, {360°/(4×N )}=11.25°, transmission portions T that contribute to the rotation of the output shaft portion 40 and transmission portions T that do not contribute to the rotation appear alternately. Considering this within a 360° range, there are 32 pairs of transmitting parts T and inserted parts H, 8 first pairs arranged at equal intervals in the circumferential direction, and 32 pairs of transmitting parts T and inserted parts H in the circumferential direction. and eight equally spaced second pairs.
However, since it is considered that four pairs each of the first pair and the second pair are sufficient to stably rotate the output shaft portion 40, the pair of the transmitting portion T and the inserted portion H is may be set to (2×N)=16. In addition to the case where N=8, it is also possible to set the number of pairs of transmitting portions T and inserted portions H to (2×N), and to provide N first pairs and N second pairs each. , a configuration in which all the transmission parts T contribute to the rotation of the output shaft part 40 is also considered possible. Furthermore, the number of pairs of transmitting portions T and inserted portions H may be set regardless of the number N. For example, if 16 pairs of transmitting portions T and inserted portions H are arranged at equal intervals in the circumferential direction, and at least 4 or more of each of the first pair and the second pair are provided, the number N can be increased. Therefore, the output shaft portion 40 can be rotated stably. In this way, the output shaft portion 40 to which the transmission portion T is fixed can be shared regardless of the number of poles N of the cam portion 12, so that manufacturing efficiency can be improved.

As described above, a wave gear device in which the number of pairs of the transmitting part T and the inserted part H is set to (2×N) pieces or to a fixed value (for example, 16 pieces) independent of the number of N. 100 as well, it is possible to reduce unnecessary stress and achieve good transmission efficiency due to the same effect as described above.

In addition, "the transmission part T is located at one end in the circumferential direction of the inserted part H" in the "first pair" means that the transmission part T is in contact with one end of the inserted part H in the circumferential direction, or Any configuration is sufficient as long as they are close to each other, and any configuration may be such that when the flex gear section 20 moves toward the transmission section T, the transmission section T can be immediately pushed in the circumferential direction by one end of the inserted section H. Bye. Similarly, "the transmission part T is located at the other end of the inserted part H in the circumferential direction" in the "second pair" means that the transmission part T is located at the other end of the inserted part H in the circumferential direction. It is sufficient that they are in contact or close to each other, and when the flex gear section 20 moves toward the transmission section T, the transmission section T can be immediately pushed in the circumferential direction by the other end of the inserted section H. Any mode is acceptable as long as it is possible.

Furthermore, "a plurality of pairs of transmitting parts T and inserted parts H are arranged at equal intervals in the circumferential direction" means that a plurality of transmitting parts T arranged at equal intervals in the circumferential direction correspond to each other. It suffices if it is inserted into a plurality of inserted parts H.

Further, as long as the first pair and the second pair can be created, the plurality of pairs of transmitting portions T and inserted portions H may not be arranged at equal intervals in the circumferential direction. In this case, from the viewpoint of stably rotating the output shaft section 40, the entire center of gravity of the output shaft section 40 and the plurality of transmission sections T fixed thereto is made to coincide with the axis AX, and the moment of inertia around the axis AX is minimized. It is preferable to aim for

From now on, further advantages of the wave gear device 100 according to this embodiment will be explained by comparing FIG. 9(a) and FIG. 9(b). FIG. 9(a) is a diagram of the strain wave gear device 100 according to the present embodiment extracted from FIG. It is a figure showing 100p.

In the wave gear device 100p according to the conventional example, configurations corresponding to the respective configurations of the wave gear device 100 according to the present embodiment are illustrated with “p” added to the end of the reference numeral. To explain the main correspondence between the conventional example and this embodiment, the wave generator 10p corresponds to the wave generation section 10, the flex spline 20p corresponds to the flex gear section 20, and the circular spline 30p corresponds to the internal gear section 30. .

As shown in FIG. 9(b), in the conventional flexspline 20p, the output shaft 40p is fixed by a fixing member Tp to a diaphragm that closes the output end of the cylindrical portion. The position of the output shaft 40p moves away from the rotating body on the input side (for example, the cam of the wave generator 10p) by a length Lp corresponding to the height.

On the other hand, as shown in FIG. 9(a), the strain wave gear device 100 according to the present embodiment has a structure in which force is transmitted from the adjacent portion 22 of the flex gear portion 20 to the output shaft portion 40 via the transmission portion T. At the same time, the adjacent portion 22 of the flex gear portion 20 and the opposing portion 41 of the output shaft portion 40 are located between the support portion 50 and the cam portion 12. Thereby, the length from the cam part 12 to the output point of the flex gear part 20 (that is, the position of the transmission part T that transmits force from the flex gear part 20 to the output shaft part 40) can be set to L, and as a result, In addition, each component can be made compact in the axial direction, and the strain wave gear device 100 can be configured in a small size.

In addition, in the wave gear device 100 according to the present embodiment, the flex gear portion 20 has a bottomless cylindrical shape (ring shape when viewed from the axial direction), and the output side end portion is shaped like the flex spline 20p according to the conventional example. Since it is not closed by a diaphragm, the flexibility of the flex gear part 20 can be maintained while ensuring a certain degree of wall thickness of the flex gear part 20. Therefore, the flex gear portion 20 can have good resistance to buckling and is less likely to be damaged. Note that the thickness of the flex gear portion 20 is not limited, but can be set to about 0.5 mm to 1 mm, for example. Further, the flex gear portion 20 has a bottomless cylindrical shape and is easier to process than a bottomed cylindrical one like the conventional flex spline 20p.

In addition, in the conventional example, the cylindrical portion of the flex spline 20p needs to have a certain length in the axial direction due to its structure, and the support portion 50p that supports the output shaft 40p is located from the meshing position of the flex spline 20p and the circular spline 30p. Go away. In such a conventional structure, stress in a direction oblique to the axis AX is likely to be applied to both the flex spline 20p and the circular spline 30p, and both gears are likely to wear out.
On the other hand, in the wave gear device 100 according to the present embodiment, the adjacent portion 22 of the flex gear portion 20 and the opposing portion 41 of the output shaft portion 40 are located between the support portion 50 and the cam portion 12, so that they are mutually connected to each other. Stress in a direction oblique to the axis AX is less likely to be applied to the flex gear part 20 and the internal gear part 30 that mesh with each other. As a result, one tooth ridge and the other tooth bottom of the flex gear section 20 and the internal gear section 30 can be brought into contact along the axial direction, and wear of each gear can be suppressed.

In addition, in the wave gear device 100 according to the present embodiment, not only the cam portion 12 but also the flex gear portion 20 and the output shaft portion 40 are hollow and ring-shaped when viewed from the axial direction, so that wiring etc. can be passed through. Space can be secured inside. In addition, according to the strain wave gearing device 100 according to the present embodiment, it goes without saying that backlash can be eliminated in principle and lost motion can be minimized.

Further, according to the strain wave gear device 100 according to the present embodiment, variations in the number of poles of the cam portion 12 not only N=2 but also N≧3 can be provided, so that it also has the following advantages. First, consider a case where the cam of the wave generator 10p is set in an elliptical shape, as in the wave gear device 100p according to the conventional example (the reference numerals in the conventional example are based on FIG. 9(b)). If the number of teeth of the circular spline 30p is Ti, the pitch circle diameter is D, the number of teeth of the flex spline 20p is t, and the pitch circle diameter is d, the reduction ratio i is "i=(Ti-t)/t= 2/t" or "i=(D-d)/d". Then, in order to reduce the value of the reduction ratio i (obtain a more decelerated rotational output), it is necessary to increase the number of teeth t or increase the ratio of the diameter d of the flex spline 20p to the diameter D of the circular spline 30p. . On the other hand, in order to increase the value of the reduction ratio i (to suppress the degree of deceleration of the rotational output), it is necessary to reduce the number of teeth t, or to reduce the ratio of the diameter d of the flex spline 20p to the diameter D of the circular spline 30p. . As described above, relying only on the elliptical cam as in the conventional example results in various restrictions on the size and conditions of the device, making it difficult to realize any reduction ratio.

On the other hand, according to the variation in which the number of poles of the cam part 12 is N≧3, even if at least one of the number of teeth Ti of the internal gear part 30 and the number of teeth t of the flex gear part 20 is kept constant. As can be seen from the reduction ratio i=N/t, the value of the reduction ratio can be increased simply by increasing the number of poles (suppressing the degree of deceleration of rotational output), and the value of the reduction ratio can be increased simply by decreasing the number of poles. It can be made smaller (to obtain a rotational output that is more decelerated). In addition to variations in the number of poles, by changing the settings of the number of teeth Ti and number t and the diameter of the flex gear section 20 and internal gear section 30, it is possible to realize an almost infinite variety of reduction ratios. can.

Note that the present invention is not limited to the above embodiments and drawings. It is possible to make changes (including deletion of constituent elements) as appropriate without changing the gist of the present invention. Below, a modified example in which a partial configuration of the wave gear device 100 is modified will be described.

(Modification 1)
As in Modification 1 shown in FIG. 10, the output shaft portion 40 may be located on the outer peripheral side of the flex gear portion 20. In this case, the opposing portion 41 of the output shaft portion 40 is located on the outer peripheral side of the adjacent portion 22 of the flex gear portion 20. The transmission portion T fixed to the opposing portion 41 extends toward the axis AX and is inserted into the inserted portion H provided in the adjacent portion 22. In addition, in FIG. 10, the diagram shown on the outer peripheral side of the diagram of the flex gear part 20 and the output shaft part 40 as seen from the axial direction shows that the cam part 12 with the number of poles N=4 moves along the axis according to the operation of the motor 213. FIG. 7 is a diagram showing the relative displacement of the transmitting part T and the inserted part H when the flex gear part 20 is viewed from the inner peripheral side in the range of 0° to 90° shown in the figure while rotating around AX. . Also in Modification 1, the number and functions of the pairs of transmitting section T and inserted section H can be set in the same manner as in the above-described embodiment.

(Modifications 2 and 3)
As shown in FIGS. 11A and 11B, the transmission section T may be fixed to the flex gear section 20, and the inserted section H may be provided on the output shaft section 40. In such a case, the output shaft portion 40 may be located on the inner circumferential side of the flex gear portion 20 as in a second modification shown in FIG. 11(a), or as in a third modification shown in FIG. 11(b). Alternatively, the output shaft portion 40 may be located on the outer peripheral side of the flex gear portion 20.
The transmission section T according to Modifications 2 and 3 is fixed to the adjacent section 22 of the flex gear section 20. The transmission portion T extends along the radial direction centered on the axis AX and toward the facing portion 41 of the output shaft portion 40, and is inserted into the inserted portion H provided in the facing portion 41.
The inserted portion H according to Modifications 2 and 3 is an elongated hole into which the transmission portion T is inserted and whose aperture in the circumferential direction is longer than the outer diameter (diameter) of the pin constituting the transmission portion T. As a result, the inserted part H can be adjusted by the relative displacement between the output shaft part 40 and the transmission part T in the circumferential direction (that is, the relative displacement between the output shaft part 40 and the flex gear part 20 in the circumferential direction). is allowed. Further, the inserted portion H allows relative displacement between the output shaft portion 40 and the transmission portion T in the radial direction (that is, relative displacement between the output shaft portion 40 and the flex gear portion 20 in the radial direction). If possible, it may be a hole with a bottom as shown in FIGS. 11(a) and 11(b), or a through hole (not shown). In Modifications 2 and 3 as well, the number and functions of the pairs of transmitting section T and inserted section H can be set in the same manner as in the above-described embodiment.

(Other variations)
Although the example in which the wave gear device 100 is incorporated into the robot 200 consisting of a vertically articulated robot has been described above, the present invention is not limited to this. The strain wave gearing device 100 can be incorporated into various robots such as horizontal articulated robots and delta-type robots. Further, the device in which the wave gear device 100 is incorporated is not limited to a robot, and may be any device as long as it is used for the purpose of obtaining a rotational output that is decelerated at a desired reduction ratio in response to a rotational input. The wave gear device 100 may be incorporated into, for example, a precision machine other than a robot, a hobby item, a home appliance, a car component, or the like.

Further, the number t of teeth of the flex gear section 20 and the number Ti of teeth of the internal gear section 30 are arbitrary as long as Ti>t. However, when the number of poles of the cam portion 12 is N, it is preferable to set the relationship between the number of teeth t and the number of teeth Ti as "Ti=t+N".

In the above example, one transmission section T is composed of one pin, but one transmission section T may be composed of a plurality of pins lined up in the axial direction. In such a case, the inserted portion H corresponding to the transmission portion T may be provided in a size that allows the plurality of pins forming the transmission portion T to be inserted therein. The inserted portion H only needs to be able to allow relative displacement between the flex gear portion 20 and the output shaft portion 40 in the circumferential direction and the radial direction.

Further, the material of the members constituting the wave gear device 100 is arbitrary and is not limited to metal, and may be appropriately selected depending on the purpose, such as engineering plastic, resin, ceramic, etc.

(1) The wave gear device 100 described above includes a transmission section T that transmits the power of the flex gear section 22 to the output shaft section 40. In the embodiment and the first modification, the transmission section T is fixed to the opposing section 41 of the output shaft section 40 and extends toward the adjacent section 22 of the flex gear section 20 . The adjacent portion 22 is provided with an inserted portion H into which the transmission portion T is inserted and which allows relative displacement between the flex gear portion 20 and the output shaft portion 40 in the circumferential direction.
(2) Furthermore, in the wave gear device 100 according to Modifications 2 and 3 shown in FIGS. 11(a) and 11(b), the transmission part T is fixed to the adjacent part 22 of the flex gear part 20, and 40 and extends toward the opposing portion 41 of the 40. The opposing portion 41 is provided with an inserted portion H into which the transmission portion T is inserted and which allows relative displacement between the flex gear portion 20 and the output shaft portion 40 in the circumferential direction.
In any of the configurations described in (1) and (2) above, there are a plurality of pairs of transmitting portions T and inserted portions H, and they are arranged in the circumferential direction. Further, the cam portion 12 has N (N is an integer of 2 or more) pole portions located at equal intervals in the circumferential direction, and engages the outer gear 21 with the inner gear 31 at N locations. Note that the number t of teeth of the outer gear 21 is preferably N fewer than the number Ti of the inner gear 31 (t=Ti−N).

According to the configurations (1) and (2) above, as described above, unnecessary stress mainly applied to the flex gear portion 20 can be suppressed, so that the wave gear device 100 is less likely to be damaged. Further, since the portion that transmits force from the flex gear portion 20 to the output shaft portion 40 is the adjacent portion 22 adjacent to the outer gear 21, it is possible to suppress the wave gear device 100 from increasing in size mainly in the axial direction. . Furthermore, by arbitrarily setting the number of poles N, various reduction ratios can be realized with a simple configuration.

(3) Furthermore, the plurality of pairs of transmitting portions T and inserted portions H may be arranged at equal intervals in the circumferential direction. According to this configuration, the output points for transmitting force from the flex gear section 20 to the output shaft section 40 can be uniformly distributed in the circumferential direction, so that the output shaft section 40 can be rotated with high torque.

(4) In addition, when the cam part 12 rotates about the axis AX, the plurality of pairs of transmitting parts T and inserted parts H are such that when the cam part 12 rotates around the axis AX, the transmitting part T is connected to one end of the inserted part H in the circumferential direction. The transmitting portion T may include a first pair located at the other end of the inserted portion H in the circumferential direction. According to this configuration, as described above, force in the circumferential direction can be efficiently transmitted from the flex gear section 20 to the output shaft section 40.

(5) Preferably, the number of pairs of transmitting portions T and inserted portions H may be 2×N or more. Note that the number of pairs of transmitting portions T and inserted portions H may be 4×N or more, or there may be a fixed number (for example, 16) regardless of the number of poles N.

(6) The inserted portion H also allows relative displacement between the flex gear portion 20 and the output shaft portion 40 in the radial direction. According to this configuration, the relative displacement between the flex gear section 20 and the output shaft section 40 in the radial direction can also be absorbed, so that the above-mentioned unnecessary stress can be reduced better.

(7) The wave gear device 100 further includes a support portion 50 that rotatably supports the output shaft portion 40 with respect to the internal gear portion 30, and the adjacent portion 22 and the opposing portion 41 are connected to the support portion 50 and the cam portion 12. located between. According to this configuration, as described above, the axial length from the cam part 12 to the output point of the flex gear part 20 (that is, the position of the transmission part T that transmits force from the flex gear part 20 to the output shaft part 40) Therefore, each structure can be made compact in the axial direction, and the strain wave gear device 100 can be configured in a small size. If the length to the output point can be suppressed in this way, one tooth ridge and the other tooth bottom in the flex gear section 20 and internal gear section 30 can be brought into contact along the axial direction, and the gears of each other can be brought into contact with each other along the axial direction. Wear can also be suppressed. Note that the support portion 50 is not limited to a cross roller bearing, and may be a ball bearing, a bearing that slides and rotatably supports the output shaft portion 40, or the like.

(8) Preferably, the transmission part T is made of a columnar pin, and the inserted part H is made of a long hole whose diameter in the circumferential direction is longer than the outer diameter of the pin.

(9) As shown in FIGS. 4 and 11(a), if the opposing part 41 of the output shaft part 40 is located on the inner peripheral side of the adjacent part 22 of the flex gear part 20, the wave gear device 100 It is possible to suppress enlargement in the radial direction.

(10) As shown in FIGS. 10 and 11(b), if the opposing part 41 of the output shaft part 40 is located on the outer peripheral side of the adjacent part 22 of the flex gear part 20, the axis of the wave gear device 100 A space can be secured inside around the AX for wiring, etc.

In the above description, descriptions of known technical matters have been omitted as appropriate in order to facilitate understanding of the present invention.

DESCRIPTION OF SYMBOLS 100... Wave gear device 10... Wave generation part 11... Cylindrical shaft part, 12... Cam part, 13... Wave bearing 20... Flex gear part 21... Outer gear, 22... Adjacent part, H... Inserted part 30... Internal gear part 31 ...Inner gear 40...Output shaft part 41...Opposing part, 42...Supported part 50...Support part T...Transmission part 200...Robot, 201...Base 210...Robot body part 211...First arm, 212...Second arm, 213...Motor 220...Controller

Claims (8)

an internal gear portion having an inner gear formed along the inner peripheral surface;
a wave generating section having a cam section that rotates around an axis in response to a rotational input;
a ring-shaped outer gear formed along an outer circumferential surface with a smaller number of teeth than the inner gear, the inner circumferential side of which is fitted into the wave generation section; and a flex having an adjacent section adjacent to the outer gear in a direction along the axis. The gear part and
an output shaft portion having a facing portion facing the adjacent portion in a radial direction centered on the axis, and rotating with the flex gear portion relative to the internal gear portion;
a transmission part fixed to the opposing part, extending toward the adjacent part, and transmitting power of the flex gear part to the output shaft part,
The cam portion has N (N is an integer of 2 or more) pole portions located at equal intervals in a circumferential direction centered on the axis, and meshes the outer gear with the inner gear at N locations,
The adjacent portion is provided with an inserted portion into which the transmission portion is inserted and which allows relative displacement between the flex gear portion and the output shaft portion in the circumferential direction;
The pair of the transmitting part and the inserted part ,
There are eight or more , arranged in the circumferential direction ,
When the cam portion rotates about the axis, the transmission portion is located at one end of the inserted portion in the circumferential direction; a second pair located at the other end in the circumferential direction;
Wave gear device. an internal gear portion having an inner gear formed along the inner peripheral surface;
a wave generating section having a cam section that rotates around an axis in response to a rotational input;
a ring-shaped outer gear formed along an outer circumferential surface with a smaller number of teeth than the inner gear, the inner circumferential side of which is fitted into the wave generation section; and a flex having an adjacent section adjacent to the outer gear in a direction along the axis. The gear part and
an output shaft portion having a facing portion facing the adjacent portion in a radial direction centered on the axis, and rotating with the flex gear portion relative to the internal gear portion;
a transmission part fixed to the adjacent part, extending toward the opposing part, and transmitting power of the flex gear part to the output shaft part,
The cam portion has N (N is an integer of 2 or more) pole portions located at equal intervals in a circumferential direction centered on the axis, and meshes the outer gear with the inner gear at N locations,
The opposing portion is provided with an inserted portion into which the transmission portion is inserted and which allows relative displacement between the flex gear portion and the output shaft portion in the circumferential direction;
The pair of the transmitting part and the inserted part ,
There are eight or more , arranged in the circumferential direction ,
When the cam portion rotates about the axis, the transmission portion is located at one end of the inserted portion in the circumferential direction; a second pair located at the other end in the circumferential direction;
Wave gear device. satisfying at least one of the following: the number of the first pair and the second pair is 4 or more, and the number of pairs of the transmitting part and the inserted part is 4×N or more;
The wave gear device according to claim 1 or 2. The opposing part is located only on either the inner circumferential side or the outer circumferential side of the adjacent part,
The wave gear device according to any one of claims 1 to 3. The pair of the transmitting part and the inserted part are arranged at equal intervals in the circumferential direction,
The wave gear device according to any one of claims 1 to 4 . The inserted portion also allows relative displacement between the flex gear portion and the output shaft portion in the radial direction.
The wave gear device according to any one of claims 1 to 5. further comprising a support part that rotatably supports the output shaft part with respect to the internal gear part,
The adjacent part and the opposing part are located between the support part and the cam part,
The wave gear device according to any one of claims 1 to 6. The transmission part consists of a columnar pin,
The inserted portion is formed of a long hole whose diameter in the circumferential direction is longer than the outer diameter of the pin.
The wave gear device according to any one of claims 1 to 7.

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