Gear mechanism, method for manufacturing a gear mechanism

Abstract

One of the objectives of this invention is to provide a gear device that improves the retention of internal tooth pins while allowing for easy machining of the pin grooves of internal teeth. [Solution] The gear device 10 of the embodiment is a gear device comprising a rocking part, an external gear rocked by the rocking part, and an internal gear 16 that meshes with the external gear, wherein the internal gear 16 has an internal gear body 18 and internal pins 17 arranged in a plurality of pin grooves 19 provided in the internal gear body 18, and a movement restricting part 184 that restricts the circumferential movement of the internal pins 17 is provided at the circumferential end of the pin groove 19 of the internal gear body 18, and the movement restricting part 184 includes a deformed deformed part 185.

Description

Technical Field

[0001] The present invention relates to a gear device and a method for manufacturing the gear device.

Background Art

[0002] There is known a reduction gear that reduces and outputs input rotation. For example, in Patent Document 1, there is described a reduction gear having a case having a plurality of pin grooves extending in the axial direction on the inner circumference, inner tooth pins disposed in the pin grooves, and external teeth having fewer teeth than the number of grooves of the pin grooves, the external teeth being disposed inside the case and meshing with the inner tooth pins in response to input rotation.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a configuration in which an external gear is meshed with an internal gear having internal tooth pins disposed in a plurality of pin grooves of a case, depending on the rotational position of the external gear, a part of the internal tooth pins may not be effectively pressed radially outward from the external gear and may receive a circumferential force from the external gear. When receiving a circumferential force, the internal tooth pins may separate from within the pin grooves, and there is a risk that the internal tooth pins may tilt within the pin grooves or the internal tooth pins may drop out of the pin grooves.

[0005] In the reduction gear described in Patent Document 1, in order to prevent the internal tooth pins from dropping out, holding protrusions that project radially inward from the edges of each pin groove are formed continuously over substantially the entire longitudinal direction of the pin groove. However, if an attempt is made to reliably obtain the dropout prevention function, the wall surface of the holding protrusion becomes parallel to the radial direction or slightly undercut, resulting in a problem that machining becomes difficult with a normal machining method for forming the pin grooves of the internal teeth. From these points, Patent Document 1 does not provide sufficient disclosure from the viewpoint of improving the retention of internal tooth pins while facilitating the machining of the internal tooth pin grooves.

[0006] This invention has been made in view of the above problems, and one of its objectives is to provide a gear device that can easily machine the pin grooves of internal teeth while improving the retention of the internal tooth pins. [Means for solving the problem]

[0007] To solve the above problems, a gear device according to one aspect of the present invention comprises a rocking part, an external gear rocked by the rocking part, and an internal gear that meshes with the external gear, wherein the internal gear has an internal gear body and internal pins arranged in a plurality of pin grooves provided in the internal gear body. A movement restricting part is provided at the circumferential end of the pin groove of the internal gear body to restrict the circumferential movement of the internal pins, and the movement restricting part includes a deformed part.

[0008] Another aspect of the present invention is a gear device. This gear device comprises a rocking part, an external gear rocked by the rocking part, and an internal gear that meshes with the external gear, wherein the internal gear has an internal gear body and internal pins arranged in a plurality of pin grooves provided in the internal gear body. Movement restricting parts that restrict the circumferential movement of the internal pins are provided at the circumferential ends of the pin grooves of the internal gear body, and intermediate grooves formed radially outward in the intermediate portion between adjacent pin grooves of the internal gear body.

[0009] A further aspect of the present invention is a method for manufacturing a gear device. This method is for manufacturing a gear device comprising a rocking part, an external gear rocked by the rocking part, and an internal gear that meshes with the external gear, wherein the internal gear has an internal gear body and internal pins arranged in a plurality of pin grooves provided in the internal gear body. This method includes a pressing step of pressing a pressing member harder than the internal gear body onto the intermediate portion between adjacent pin grooves of the internal gear body.

[0010] Furthermore, any combination of the above components, or in which the components or expressions of the present invention are mutually substituted among methods, systems, etc., are also valid embodiments of the present invention. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a gear device that can easily machine the pin grooves of internal teeth while improving the retention of the internal tooth pins. [Brief explanation of the drawing]

[0012] [Figure 1] This is a cross-sectional view showing a gear device according to an embodiment. [Figure 2] Figure 1 is a cross-sectional view along line AA showing the internal gear of the gear assembly. [Figure 3] This is a cross-sectional view showing an enlarged view of the movement restricting portion of the internal gear shown in Figure 2. [Figure 4] Figure 2 is a process diagram showing an example of the manufacturing process for internal gears. [Figure 5] This is a process diagram showing another example of the manufacturing process for internal gears. [Figure 6] This is a cross-sectional view showing a modified example of an internal gear. [Figure 7] This is a process diagram showing yet another example of the manufacturing process for internal gears. [Modes for carrying out the invention]

[0013] The present invention will be described below with reference to the drawings, based on preferred embodiments. In embodiments and modifications, the same or equivalent components and members will be denoted by the same reference numerals, and redundant explanations will be omitted as appropriate. In addition, the dimensions of the members in each drawing will be enlarged or reduced as appropriate for ease of understanding. Furthermore, some members that are not important for explaining the embodiments will be omitted from the drawings.

[0014] Terms including ordinal numbers such as the first and the second are used to describe various components, but these terms are used only for the purpose of distinguishing one component from another, and the components are not limited by these terms.

[0015] [Embodiment] Referring to the drawings, the gear device 10 according to the embodiment will be described. First, the overall configuration of the gear device 10 will be described with reference to FIG. 1, and the movement restricting portion, which is a characteristic configuration of the embodiment, will be described later. FIG. 1 is a cross-sectional view in a side view schematically showing the gear device 10.

[0016] In the embodiment, the gear device 10 is a gear device that causes one of the internal gear and the external gear to rotate by swinging the external gear that meshes with the internal gear, and outputs the generated rotation component from the output member to the driven member. In particular, in the example of FIG. 1, the gear device 10 is a so-called distribution type eccentric swing type reduction gear in which the crankshaft is arranged at a position offset from the axis of the internal gear.

[0017] The gear device 10 mainly includes a crankshaft 20, external gears 14 and 15, an internal gear 16, carriers 35 and 36, a casing 6, main bearings 26 and 27, crankshaft bearings 37 and 38, and an input gear 71. The gear device 10 decelerates and outputs the rotation input to the input gear 71 from a drive source (not shown) such as a servo motor that drives the gear device 10.

[0018] Hereinafter, the direction along the central axis line La of the internal gear 16 is referred to as the "axial direction", and the circumferential direction and the radial direction of the circle centered on the central axis line La are referred to as the "circumferential direction" and the "radial direction", respectively. Also, hereinafter, for the sake of convenience, one side in the axial direction (the right side in the figure) is referred to as the input side, and the other side (the left side in the figure) is referred to as the anti-input side. Also, the rotation center lines of the input gear 71 and the crankshaft 20 are indicated by reference numeral Lb.

[0019] The configuration of each part of the gear device 10 will be described. The carriers 35 and 36 include a first carrier 35 disposed on the side of the outer gear wheels 14 and 15 opposite to the input side, and a second carrier 36 disposed on the side of the outer gear wheels 14 and 15 on the input side. The casing 6 has a cylindrical shape surrounding the gear device 10, and an internal gear wheel 16 is provided on the inner peripheral surface. The casing 6 supports the outer peripheral sides of the main bearings 26 and 27. The casing 6 includes a second outer peripheral portion 62, a first outer peripheral portion 61, and a third outer peripheral portion 63 in order from the opposite input side to the input side.

[0020] The main bearings 26 and 27 include a first main bearing 26 disposed on the side of the outer gear wheels 14 and 15 opposite to the input side, and a second main bearing 27 disposed on the side of the outer gear wheels 14 and 15 on the input side. The main bearings 26 and 27 support the casing 6. The main bearings 26 and 27 in this example are angular roller bearings, but are not limited thereto. The carriers 35 and 36 are rotatably supported by the casing 6 via the main bearings 26 and 27.

[0021] The crankshaft bearings 37 and 38 are disposed between the crankshaft 20 and the carriers 35 and 36, and rotatably support the crankshaft 20 with respect to the carriers 35 and 36. The crankshaft bearings 37 and 38 in this example are tapered roller bearings, but are not limited thereto.

[0022] Three crankshafts 20 are arranged at positions offset from the central axis La of the internal gear wheel 16. The three crankshafts 20 are arranged at equal intervals in the circumferential direction. Only one crankshaft 20 is shown in FIG. 1. The crankshaft 20 has a plurality of eccentric portions 24 and 25 that are eccentric with respect to the rotation center line Lb of the crankshaft 20 in order to swing the outer gear wheels 14 and 15. The eccentric portions 24 and 25 exemplify the swinging portions. The crankshaft 20 in this example has two eccentric portions 24 and 25 whose eccentric phases are shifted by 180° from each other.

[0023] The crankshaft 20 is supported by the first carrier 35 and the second carrier 36 via crankshaft bearings 37 and 38. The crankshaft bearing 37 on the non-input side is located between the crankshaft 20 and the first carrier 35 on the non-input side of the external gears 14 and 15. The crankshaft bearing 38 on the input side is located between the crankshaft 20 and the second carrier 36 on the input side of the external gears 14 and 15.

[0024] The input gear 71 is provided at the input end of each crankshaft 20. Figure 1 shows only one input gear 71. As mentioned above, rotation from the drive source is input to the input gear 71.

[0025] The external gears 14 and 15 are provided with eccentric portions 24 and 25 via eccentric rollers 47 and each has three internal pin holes 41 and 42 and three oscillating holes 45 and 46, which are arranged at equal intervals in the circumferential direction. An internal pin 48 is inserted through each internal pin hole 41 and 42. The eccentric portions 24 and 25 of the crankshaft 20 are inserted through each oscillating hole 45 and 46, and a plurality of eccentric rollers 47 are interposed between the oscillating holes 45 and 46 and the eccentric portions 24 and 25. The external gears 14 and 15 are configured to oscillate as the external teeth formed on the outer circumference of the external gears 14 and 15 move in contact with the internal gear 16.

[0026] The internal pin 48 extends axially from the first carrier 35 and is fixed to the second carrier 36 by bolt B1. The internal pin 48 is inserted through the internal pin holes 41 and 42 of the external gears 14 and 15 with a gap between them.

[0027] One of the first carrier 35 and the casing 6 becomes an output member that outputs rotational power to a driven member (not shown), and the other becomes a fixed member that is fixed to an external member (not shown) that supports the gear device 10. In the example in Figure 1, the first carrier 35 is the output member 40.

[0028] The internal gear 16 and the movement restricting mechanism will be explained with reference to Figures 2 and 3. Figure 2 is a cross-sectional view taken along line AA showing the internal gear 16 of the gear assembly 10 in Figure 1. The internal gear 16 has an internal gear body 18 integrated with the inner circumference of the casing 6 and internal tooth pins 17 arranged in a pin groove 19 formed in the internal gear body 18. The internal tooth pins 17 are cylindrical pin members extending in the axial direction, and constitute the internal teeth of the internal gear 16, meshing with the external teeth of the external gears 14 and 15. The number of internal tooth pins 17 is slightly greater than the number of external teeth of the external gears 14 and 15 (only one in this example). The internal tooth pins 17 are rotatably supported in the pin groove 19 that extends in the axial direction.

[0029] Figure 3 is an enlarged cross-sectional view showing the movement restricting portion 184 of the internal gear 16. A movement restricting portion 184 is provided at the circumferential end of the pin groove 19 of the internal gear body 18 to restrict the circumferential movement of the internal tooth pins 17. The symbol C1 indicates the internal tooth pin center circle passing through the center S1 of each internal tooth pin 17 incorporated into the internal gear 16 in a plane perpendicular to the internal axis direction.

[0030] As an example, in the radial direction, the position of the inner circumferential surface 181 of the internal gear body 18 before the pin groove 19 is formed is substantially the same as the internal pin center circle C1, or radially outward from the internal pin center circle C1. In this case, the intermediate portion 182 between the pin groove 19 and adjacent pin grooves 19, formed by conventional processing methods such as grinding, is also substantially the same as the internal pin center circle C1, or radially outward from the internal pin center circle C1. In this example, when viewed from the axial direction, the range in which the pin groove 19 surrounds the internal pin 17 is less than half of the 360° circumference of the internal pin 17, which is 180° or less. In this case, the internal pin 17 placed within the pin groove 19 is at risk of floating up or falling out of the pin groove 19.

[0031] Therefore, in this embodiment, a movement restricting portion 184 is provided at the circumferential end of the pin groove 19 of the internal gear body 18 to restrict the circumferential movement of the internal tooth pin 17. Typically, the movement restricting portion 184 protrudes radially inward from the central circle C1 of the internal tooth pin in the radial direction. In this case, the range in which the pin groove 19 surrounds the internal tooth pin 17 when viewed from the axial direction exceeds 180°, so the internal tooth pin 17 can be largely prevented from floating up or falling out of the pin groove 19.

[0032] The movement restricting portion 184 may be provided over the entire axial extension range of the internal tooth pin 17, or it may be provided over a portion of the axial extension range of the internal tooth pin 17. For example, the movement restricting portion 184 may be provided in a region corresponding to the axial end of the internal tooth pin 17. In other words, the movement restricting portion 184 includes a portion 186 that radially overlaps with the axial end of the internal tooth pin 17. In this case, machining becomes easier than when the movement restricting portion 184 is provided over the entire length.

[0033] It is also possible to form a movement restricting portion 184 that protrudes radially inward from the internal tooth pin center circle C1 using grinding, but this has the disadvantage of increasing the processing time because the pin groove 19 contains an undercut. Therefore, in this embodiment, the movement restricting portion 184 includes a plastically deformed portion 185. That is, plastic deformation moves the material of the intermediate portion 182 closer to the pin groove 19, causing the circumferential end of the pin groove 19 to protrude radially inward from the internal tooth pin center circle C1. In other words, the deformed portion 185 is the part of the intermediate portion 182 that has been plastically deformed so that it approaches the internal tooth pin 17.

[0034] To form the movement restricting portion 184, it is conceivable to move a portion of the material of the internal gear body 18 toward the pin groove 19. In this embodiment, the internal gear body 18 has an intermediate groove 183 formed radially outward in the intermediate portion 182 between the multiple pin grooves 19. In this case, the material that existed in the portion of the intermediate portion 182 corresponding to the intermediate groove 183 before machining can be moved circumferentially toward the pin groove 19. The shape of the intermediate groove 183 is not limited, but in this example, the intermediate groove 183 is a V-shaped groove, for example, which has a valley shape in a cross-section viewed from the axial direction, where the width in the circumferential direction gradually narrows toward the bottom.

[0035] Referring to Figure 4, the method for forming the movement restricting portion 184 by plasticity will be explained. Figure 4 is a process diagram showing an example of the manufacturing process of an internal gear 16, and in particular shows the pressing process S110. In this example, the movement restricting portion 184 is formed by the pressing process S110, in which a pressing member 55, which is harder than the internal gear body 18, is pressed against the intermediate portion 182 between the multiple pin grooves 19 of the internal gear body 18. There are no limitations on the shape of the pressing member 55, but the pressing member 55 in this example has radially outward-facing corners 552 on the pressing surface. The shape, hardness, material, etc. of the pressing member 55 can be determined by experiment or simulation from the viewpoint of realizing the desired material movement shape.

[0036] Although not shown in the diagram, the outer shape of the internal gear body 18 is formed by machining, and the pin groove 19 is formed on the internal gear body 18 with the formed outer shape by grinding with a grinding wheel. A predetermined heat treatment may be performed during this process.

[0037] Figure 4(A) shows the state before the movement restricting portion 184 is formed. As shown in this figure, the pin groove 19 before the movement restricting portion 184 is formed has a range that holds the internal tooth pin 17 narrower than the internal tooth pin center circle C1. This is to facilitate grinding or abrasive machining for the initial machining of the pin groove 19. Here, a pin member 58 is placed in the pin groove 19 of the internal gear body 18 that is being formed. In other words, the pressing process S110 is performed with the pin member 58 placed in the pin groove 19. In this case, excessive material movement can be suppressed. In this example, the pin member 58 is a dummy pin 60 with a diameter similar to that of the internal tooth pin 17. The diameter of the dummy pin 60 may be less than or equal to the diameter of the internal tooth pin 17, but in this example, its diameter is larger than that of the internal tooth pin 17. The shape and hardness of the dummy pin 60 can be set by experiment or simulation from the viewpoint of realizing the desired material movement shape.

[0038] The pin member 58 may be the internal tooth pin 17 itself. In this case, it can be expected that a gap will be formed between the movement restricting portion 184 and the internal tooth pin 17 due to springback after the movement restricting portion 184 undergoes plastic deformation.

[0039] Figure 4(B) shows the state in which the pressing member 55 is pressed against the intermediate portion 182. Here, as indicated by arrow g, the material present in the portion of the intermediate portion 182 corresponding to the intermediate groove 183 moves circumferentially along the inclined surface 554 of the pressing member 55 toward the pin groove 19. During this process, the internal gear body 18 may be heated.

[0040] Figure 4(C) shows the state in which the pressing member 55 is separated from the intermediate portion 182. Note that the pressing of the pressing member 55 as shown in Figure 4(B) and the separation of the pressing member 55 as shown in Figure 4(C) may be repeated.

[0041] Once the movement restricting section 184 is formed, the dummy pin 60 is removed axially, and the internal tooth pin 17 is inserted axially. This completes the manufacturing of the internal gear 16.

[0042] Referring to Figure 5, another example of the pressing process S110 will be described. Figure 5 is a process diagram showing another example of the manufacturing process of the internal gear 16. From the viewpoint of smoothly executing the pressing process S110, a lower groove 187 may be provided in the intermediate portion 182 before forming the movement restricting portion 184. The lower groove 187 can be formed, for example, by grinding with an abrasive wheel. The lower groove 187 may be formed at the same time as the pin groove 19, or separately. The shape of the lower groove 187, etc., can be determined by experiment or simulation from the viewpoint of smoothly executing the pressing process S110.

[0043] A modified example of the internal gear 16 will be described with reference to Figure 6. Figure 6 is a cross-sectional view showing modified example 16B of the internal gear 16. After the movement restricting portion 184 is formed, if the pressing member 55 is removed, the shape of the movement restricting portion 184 may change due to springback or changes over time. Therefore, in modified example 16B, a groove contact member 51 that abuts radially against the intermediate groove 183 is engaged with the intermediate groove 183. In this case, since the groove contact member 51 is engaged, the change in the shape of the movement restricting portion 184 can be suppressed. In addition, in order to maintain the position of the multiple groove contact members 51, the axial ends of the groove contact members 51 may be fixed to an annular member (not shown). In other words, the multiple groove contact members 51 shown in Figure 6 may be connected in an annular shape to form a single integrated member. The groove contact member 51 may be the pressing member 55 used in the pressing process S110, or it may be a member different from the pressing member 55. By using the groove contact member 51, the deformation state can be maintained even when the movement restricting portion 184 is deformed by elastic deformation.

[0044] Referring to Figure 7, yet another example of the pressing process S110 will be described. Figure 7 is a process diagram showing yet another example of the manufacturing process of the internal gear 16. This figure is a view of the internal gear 16 from diagonally above after the movement restricting portion 184 has been formed, and for ease of understanding, the pin member 58 is omitted. In the above description, an example was shown in which the movement restricting portion 184 is formed over the entire axial extension range of the internal tooth pin 17, but the present invention is not limited thereto, and the movement restricting portion 184 may be provided in a part of the axial extension range of the internal tooth pin 17. In the example of Figure 7, the movement restricting portion 184 is formed at the upper axial end of the pin groove 19 in the figure. In this example, by moving the pressing member 55 axially along the intermediate portion 182, the material of the intermediate portion 182 is moved closer to the pin groove 19, causing the circumferential end of the pin groove 19 to protrude.

[0045] In the pressing process of this example, the pressing member 55 is moved axially while in contact with the intermediate portion 182, thereby moving the material of the intermediate portion 182 toward the pin groove 19 and causing the circumferential end of the pin groove 19 to protrude. The pressing member 55 may have a shape such as a pyramid, cone, or elliptical pyramid, with its apex extending axially from the base.

[0046] The circumferential groove width and groove depth of the intermediate groove 183 may be constant in the axial direction, or at least one of the circumferential groove width and the radial groove depth of the intermediate groove 183 may have a tapered shape that decreases as it moves away from the end face of the internal gear body 18. In the example of Figure 7, the circumferential groove width and groove depth of the intermediate groove 183 have a tapered shape that decreases as it moves away from the end face of the internal gear body 18. In this case, the resistance when moving the pressing member 55 in the axial direction can be reduced, and the machinability can be improved.

[0047] The deceleration operation of the gear unit 10 will now be explained. The rotational power input from the drive source is distributed to the three input gears 71, and the three input gears 71 rotate in the same phase. As the three input gears 71 rotate, the eccentric parts 24 and 25 of the crankshaft 20 rotate around the rotational center line passing through the crankshaft 20, and the external gears 14 and 15 oscillate due to these eccentric parts 24 and 25. In other words, the eccentric parts 24 and 25 correspond to the oscillating parts that oscillate the external gears. As the external gears 14 and 15 oscillate, the meshing positions of the external gears 14 and 15 and the internal tooth pins 17 of the internal gear 16 shift sequentially. As a result, with each rotation of the crankshaft 20, a rotation occurs in either the external gears 14 and 15 or the internal gear 16 by an amount equivalent to the difference between the number of teeth of the external gears 14 and 15 and the number of internal tooth pins 17 of the internal gear 16. In this embodiment, the external gears 14 and 15 rotate on their own, and a reduced rotation is output from the first carrier 35, which rotates in sync with the rotational component of the external gears 14 and 15. As the first carrier 35 rotates, the first carrier 35 acts as an output member 40, and the driven member connected to the first carrier 35 is rotationally driven.

[0048] The features of the gear device 10 configured as described above will now be explained. The gear device 10 is a gear device comprising a rocking part, an external gear 14 rocked by the rocking part, and an internal gear 16 that meshes with the external gear 14. The internal gear 16 has an internal gear body 18 and internal pins 17 arranged in a plurality of pin grooves 19 provided in the internal gear body 18. Movement restricting parts 184 that restrict the circumferential movement of the internal pins 17 are provided at the circumferential ends of the pin grooves 19 of the internal gear body 18, and the movement restricting parts 184 include a deformed deformed part 185.

[0049] With this configuration, the retention of the internal tooth pin 17 is improved by the movement restricting portion 184, and the movement restricting portion 184 can be formed using deformation processing, making it easy to machine the pin groove 19 of the internal gear 16. In addition, the possibility of the internal tooth pin 17 separating from or falling out of the pin groove 19 can be reduced.

[0050] The above is a description of the embodiment.

[0051] The present invention has been described above based on the embodiments. These embodiments are illustrative, and it will be understood by those skilled in the art that various modifications and changes are possible within the scope of the claims of the present invention, and that such modifications and changes are also within the scope of the claims of the present invention. Accordingly, the descriptions and drawings herein should be treated as illustrative rather than limiting.

[0052] (modified version) The following describes modified examples. In the drawings and descriptions of the modified examples, components and parts that are the same or equivalent as those in the embodiments are denoted by the same reference numerals. Descriptions that overlap with those in the embodiments will be omitted as appropriate, and the descriptions will focus on the configurations that differ from those in the embodiments.

[0053] In the explanation of Figure 7, an example is shown in which a movement restricting portion 184 is formed at the upper axial end of the pin groove 19 in the figure, but the present invention is not limited to this. For example, the movement restricting portions may be formed at both axial ends of the pin groove.

[0054] In the above description, an example was shown in which the gear device 10 is a so-called distribution type reduction gear in which a plurality of crankshafts 20 are arranged at positions offset from the axis of the internal gear 16. However, the present invention is not limited to this, and various gear devices can be employed that have an oscillating part, an external gear that is oscillated by the oscillating part, and an internal gear that meshes with the external gear. For example, the gear device 10 may be a so-called center crank type reduction gear in which a crankshaft is arranged at the axis of the internal gear.

[0055] Furthermore, the gear device 10 may also be a flexible meshing gear device having a vibrator with a long axis and a short axis, wherein the vibrator flexes the external gear, causing the external gear to mesh with the internal gear. In other words, the oscillating part that oscillates the external gear includes the vibrator of the flexible meshing gear device. "Oscillating the external gear by the oscillating part" does not only refer to the oscillating of the external gear by the eccentric part of an eccentric shaft, such as in the gear device 10, where the axis is eccentric with respect to the axis. "Oscillating the external gear by the oscillating part" also corresponds to a flexible meshing gear device that includes a vibrator with a non-circular axis located inside the external gear, causing the external gear to flex.

[0056] The above description shows an example in which the deformable portion 185 is formed by plastic deformation, but the present invention is not limited to this. For example, the deformable portion may be clamped in a deformed state due to elastic deformation, and that state may be maintained.

[0057] The above description shows an example in which the gear unit 10 has two external gears, but the present invention is not limited to this. The gear unit may have one or three or more external gears.

[0058] Each of these modifications produces the same functions and effects as the embodiments.

[0059] Any combination of the embodiments and modifications described above is also useful as an embodiment of the present invention. The new embodiments resulting from these combinations possess the combined effects of both the respective embodiments and modifications. [Explanation of symbols]

[0060] 10 Gear mechanism, 14 External gear, 16 Internal gear, 17 Internal pin, 18 Internal gear body, 19 Pin groove, 51 Groove contact member, 55 Pressing member, 58 Pin member, 60 Dummy pin, 182 Intermediate part, 183 Intermediate groove, 184 Movement restricting part, 185 Deformation part.

Claims

1. A gear device comprising a rocking part, an external gear that is rocked by the rocking part, and an internal gear that meshes with the external gear, The internal gear comprises an internal gear body and internal tooth pins arranged in a plurality of pin grooves provided in the internal gear body. A movement restricting portion is provided at the circumferential end of the pin groove of the internal gear body, which restricts the circumferential movement of the internal tooth pin. The aforementioned movement restricting portion includes a deformed portion. Gear mechanism.

2. The gear device according to claim 1, wherein the deformed portion is formed by plastic deformation.

3. The movement restricting portion includes a portion that overlaps radially with the axial end of the internal tooth pin. The gear apparatus according to claim 1 or 2.

4. A gear device comprising a rocking part, an external gear that is rocked by the rocking part, and an internal gear that meshes with the external gear, The internal gear comprises an internal gear body and internal tooth pins arranged in a plurality of pin grooves provided in the internal gear body. A movement restricting portion is provided at the circumferential end of the pin groove of the internal gear body, which restricts the circumferential movement of the internal tooth pin. The internal gear body has an intermediate groove formed radially outward in the middle portion between adjacent pin grooves. Gear mechanism.

5. The movement restricting portion includes a portion that overlaps radially with the axial end of the internal tooth pin. The gear apparatus according to claim 4.

6. The groove contact member has a groove contact member that abuts radially against the intermediate groove. The gear apparatus according to claim 4.

7. At least one of the circumferential groove width and the radial groove depth of the intermediate groove has a tapered shape that decreases as it moves away from the end face of the internal gear body. The gear apparatus according to claim 4.

8. A method for manufacturing a gear apparatus comprising a rocking part, an external gear that is rocked by the rocking part, and an internal gear that meshes with the external gear, The internal gear comprises an internal gear body and internal tooth pins arranged in a plurality of pin grooves provided in the internal gear body. This includes a pressing step in which a pressing member, which is harder than the internal gear body, is pressed against the intermediate portion between adjacent pin grooves of the internal gear body. A method for manufacturing a gear system.

9. The pressing step is performed with the pin member positioned in the pin groove. The manufacturing method according to claim 8.

10. The aforementioned pin member is a dummy pin with a larger diameter than the aforementioned internal tooth pin. The manufacturing method according to claim 9.

11. The pressing step is performed by pressing the pressing member against the intermediate groove, which is recessed radially outward and provided in the intermediate portion. The manufacturing method according to claim 8.

12. The pressing step includes moving the pressing member in the axial direction while it is in contact with the intermediate portion. The manufacturing method according to claim 8.

Images