JP7360260B2 - Decelerator - Google Patents

Description

The present invention relates to a speed reducer.

BACKGROUND ART In rotating equipment such as industrial robots and machine tools, reduction gears are used to reduce the rotation of a rotational drive source (for example, see Patent Document 1).

The reducer described in Patent Document 1 includes an outer cylinder that also serves as a casing, a carrier rotatably supported within the outer cylinder, a plurality of crankshafts rotatably supported on the outer peripheral edge of the carrier, and a plurality of crankshafts rotatably supported on the outer peripheral edge of the carrier. Two rocking gears that rotate in response to the rotation of the eccentric part of the crankshaft, a plurality of internal tooth pins arranged in an area facing the outer peripheral surface of the two rocking gears in the outer cylinder, and a plurality of crankshafts. and an input rotating body for inputting rotational power to the input rotating body. In this reduction gear, an input rotating body is connected to a rotational drive source such as a motor, and a carrier is coupled as an output rotating body to a rotating body such as a turntable. Further, each crankshaft is provided with two eccentric parts for rotating the two rocking gears in different phases (for example, phases shifted by 180 degrees).

A plurality of pin grooves extending in the axial direction are formed at predetermined intervals in the circumferential direction in a region of the inner circumferential surface of the outer cylinder that faces the outer circumferential surfaces of the two rocking gears. The plurality of internal pins described above are rotatably arranged in each pin groove. External teeth having a smaller number of teeth than the number of pin grooves (the number of internally toothed pins) are formed on the outer peripheral surfaces of each of the two rocking gears. When the two rocking gears rotate together with the eccentric part of the crankshaft, each of the external teeth meshes with the internal pin and receives a reaction force from the internal pin during one revolution, causing the gears to rotate at a predetermined pitch in the opposite direction to the rotating direction. Rotate (rotate). At this time, the rotation (autorotation) of the two rocking gears is transmitted to the carrier via the plurality of crankshafts. As a result, the rotation transmitted from the input rotating body to the crankshaft and the rocking gear is reduced to a predetermined reduction ratio and output to the carrier.
Note that the internal pins disposed in each pin groove of the outer cylinder are formed to have an axial length spanning the external teeth of the two rocking gears. That is, approximately half of the axial region of each internal pin meshes with the external teeth of one of the swing gears, and the remaining approximately half of the axial region meshes with the external teeth of the other swing gear.

Patent No. 5798882

In the reducer described in Patent Document 1, the depth of meshing between the external teeth and the internal pin changes depending on the rotational position of the rocking gear, and depending on the rotational position, some of the internal pins do not receive pressing force from the external teeth. There are times. At this time, a part of the internal pin may separate from the pin groove, and the posture of the internal pin may tilt toward the oscillating gear. When the internal pin tilts in the direction of the swing gear, there is a concern that the axial end of the internal pin may strongly hit the external teeth of the swing gear, causing damage to the external teeth.

In particular, as in the reducer described in Patent Document 1, when one internal pin meshes with the external teeth of one oscillating gear and the external teeth of the other oscillating gear, the internal pins are in different phases. It simultaneously receives pressing forces of different magnitudes and directions from the external teeth of two oscillating gears rotating at the same time. For this reason, when the two rocking gears rotate, the internal toothed pin is inclined significantly, and the axial end of the internal toothed pin is likely to be strongly pressed against the external teeth of the rocking gear.

Further, Patent Document 1 describes that crowning is performed on the ends of internal pins and external teeth. When crowning is performed on the end of the internal pin or the external tooth, it is possible to prevent the axial end of the internal pin from strongly hitting the external tooth of the oscillating gear when the internal pin is tilted. However, if crowning is applied to the end of the internal pin or external tooth, there is a concern that the internal pin will be displaced from the pin groove and the angle of inclination will become large during operation, making the operation of the reducer unstable. be done.

The present invention provides a speed reducer that can suppress unstable behavior of pins within pin grooves.

A speed reducer according to one aspect of the present invention includes a case having a plurality of pin grooves extending in the axial direction on an inner periphery, an internally toothed pin disposed in each of the plurality of pin grooves, and a case with a case having a plurality of pin grooves extending in the axial direction, a plurality of oscillating gears having external teeth with a small number of teeth, arranged axially side by side inside the case, and pivoting and rotating while meshing with the corresponding internally toothed pin in the pin groove in response to input rotation; and a holding protrusion that protrudes inward in the radial direction of the case from an edge in a direction perpendicular to the longitudinal direction of each of the pin grooves to prevent each of the internally toothed pins from falling off. , a plurality of the internally toothed pins are arranged so as to mesh independently with the external teeth of each of the rocking gears , and the holding protrusion is continuously formed over almost the entire length of each of the pin grooves in the longitudinal direction. There is.

In this case, when the external teeth of one oscillating gear apply a pressing force to the internal pin, it is possible to prevent the pressing force applied to the internal pin from acting on the other oscillating gear. Therefore, it is possible to eliminate unnecessary resistance friction during the rotation of the plurality of rocking gears, improve the power transmission efficiency of the reducer, and suppress heat generation due to frictional heat. Further, in this case, each internal tooth pin is not engaged across the external teeth of the plurality of rocking gears, and therefore tends to separate from the pin groove when the rocking gear rotates. However, since the edge of each pin groove is provided with a holding protrusion , it is possible to prevent the internal pin from falling out of the pin groove.

The holding protrusion may hold the internal pin in a non-contact state with respect to the external teeth of the oscillating gear when the oscillating gear is largely separated from the inner circumferential surface of the case. good.

In the above-mentioned speed reducer, the holding protrusion on the edge of the pin groove can prevent the pin from falling out of the pin groove, so that unstable behavior of the pin within the pin groove can be suppressed.

FIG. 1 is a vertical cross-sectional view of a reduction gear according to an embodiment. FIG. 2 is an enlarged cross-sectional view of a part of FIG. 1 of the speed reducer of the embodiment. FIG. 3 is a view taken along arrow III in FIG. 2 of the speed reducer of the embodiment.

Next, embodiments of the present invention will be described based on the drawings.

FIG. 1 is a longitudinal cross-sectional view of a reduction gear 10 of this embodiment, and FIG. 2 is a cross-sectional view showing a part of FIG. 1 in an enlarged manner.
The reducer 10 has an input side connected to a rotational drive source such as an electric motor (not shown), and an output side connected to a rotated body (not shown).

The speed reducer 10 includes a fixed block (not shown) attached to the equipment used, a first carrier block 15A and a second carrier block 15B integrally coupled to the fixed block, and a first carrier block 15A and a second carrier block 15B. An outer cylinder 17 (holding member, case) rotatably supported on the outer circumferential side via a bearing 16, and a plurality (for example, three) rotatably supported by the first carrier block 15A and the second carrier block 15B. , and a first swing gear 19A and a second swing gear 19B that rotate together with the two eccentric parts 18a and 18b of each crankshaft 18.

A perforated disk-shaped first carrier block 15A is stacked on the fixed block, and the first carrier block 15A is integrally fixed by bolts or the like. Further, a second carrier block 15B is fixed to an end surface (lower surface in FIG. 1) of the first carrier block 15A opposite to the fixed block by fastening bolts or the like. The second carrier block 15B includes a perforated disk-shaped substrate portion 15Ba and a plurality of support columns (not shown) extending from the end surface of the substrate portion 15Ba toward the first carrier block 15A. In the second carrier block 15B, the end faces of the support columns are butted against the end faces of the first carrier block 15A, and each support support is fixed to the first carrier block 15A. An axial gap is ensured between the first carrier block 15A and the substrate portion 15Ba of the second carrier block 15B. A first swing gear 19A and a second swing gear 19B are arranged in this gap.
Note that escape holes (not shown) are formed in the first rocking gear 19A and the second rocking gear 19B, through which each support portion of the second carrier block 15B passes. The relief holes are formed to have a sufficiently large inner diameter with respect to the support pillars so that the support pillars do not interfere with the rotational movement of the first rocking gear 19A and the second rocking gear 19B.

The outer cylinder 17 is disposed across the outer circumferential surface of the first carrier block 15A and the outer circumferential surface of the substrate portion 15Ba of the second carrier block 15B. Both ends of the outer cylinder 17 in the axial direction are rotatably supported by the first carrier block 15A and the base plate portion 15Ba of the second carrier block 15B via bearings 16. Further, on the inner circumferential surface of the axially central region of the outer cylinder 17 (the area facing the outer circumferential surfaces of the first rocking gear 19A and the second rocking gear 19B), there is a A plurality of pin grooves 60 extending in the axial direction are formed. The plurality of pin grooves 60 are provided on the inner peripheral surface of the outer cylinder 17 at predetermined intervals in the circumferential direction. A pair of substantially cylindrical internal pins 20A and 20B (pins) are rotatably accommodated in each pin groove 60. Each of the internal pins 20A, 20B is crowned on both ends in the axial direction.

The first swing gear 19A and the second swing gear 19B are arranged inside the outer cylinder 17 in line with each other in the axial direction. Further, the first swing gear 19A and the second swing gear 19B are formed to have an outer diameter slightly smaller than the inner diameter of the outer cylinder 17. External teeth 19Aa, 19Ba are provided on the outer circumferential surfaces of the first oscillating gear 19A and the second oscillating gear 19B, and are in meshed contact with a plurality of internally toothed pins 20A, 20B arranged on the inner circumferential surface of the outer cylinder 17. is formed. The number of teeth of the external teeth 19Aa and 19Ba formed on the outer circumferential surfaces of the first oscillating gear 19A and the second oscillating gear 19B is the number of grooves of the pin groove 60 formed on the outer cylinder 17 (the number of grooves of the pin groove 60 formed on the outer cylinder 17 (inner tooth pin 20A, 20B) is set slightly smaller (for example, one smaller) than the number of 20B.

Note that one of the internal pins 20A disposed in the pin groove 60 on the outer cylinder 17 side is formed to have an axial length that is approximately the same as the thickness (length in the axial direction) of the first rocking gear 19A. The other internal pin 20B is formed to have an axial length that is approximately the same as the thickness (length in the axial direction) of the second rocking gear 19B. A pair of internally toothed pins 20A and 20B housed in the same pin groove 60 mesh independently with external teeth 19Aa and 19Ba of the first swing gear 19A and the second swing gear 19B, respectively.

The plurality of crankshafts 18 are arranged on the same circumference centered on the rotation center axis c1 of the first carrier block 15A and the second carrier block 15B. Each crankshaft 18 is rotatably supported by a first carrier block 15A and a second carrier block 15B via bearings 22. The eccentric portions 18a and 18b of each crankshaft 18 pass through the first swing gear 19A and the second swing gear 19B, respectively. Each eccentric part 18a, 18b is rotatably engaged with a support hole 21 formed in the first rocking gear 19A and the second rocking gear 19B, respectively, via an eccentric part bearing 23.

The two eccentric portions 18a and 18b of each crankshaft 18 are eccentric about the axis of the crankshaft 18 so that their phases are shifted by 180 degrees from each other. Further, in this embodiment, the carrier is composed of a first carrier block 15A and a second carrier block 15B. The first carrier block 15A and the second carrier block 15B are connected to the first and second rocking gears 19A and 19B in the rotation direction of the first and second rocking gears 19A and 19B via the plurality of crankshafts 18. It is locked in. In the case of this embodiment, since the first carrier block 15A and the second carrier block 15B are integrally coupled to the fixed block, the first carrier block 15A and the second carrier block 15B do not rotate, and the first and second carrier blocks Swing gears 19A and 19B also do not rotate.

When the plurality of crankshafts 18 rotate in one direction in response to an external force, the eccentric portions 18a and 18b of the crankshafts 18 rotate in the same direction at a predetermined radius, and accordingly, the first oscillating gear 19A and the second oscillating gear rotate. Gears 19B rotate in the same direction with the same radius. At this time, each of the external teeth 19Aa and 19Ba of the first oscillating gear 19A and the second oscillating gear 19B mesh with a plurality of internally toothed pins 20A and 20B held on the inner periphery of the outer cylinder 17.

In the reducer 10 of the present embodiment, the number of external teeth 19Aa and 19Ba of the first oscillating gear 19A and the second oscillating gear 19B is greater than the number of internally toothed pins 20A and 20B on the outer cylinder 17 side. Since it is set slightly less, the outer cylinder 17 is pushed around by a predetermined pitch in the same direction as the turning direction while the first swing gear 19A and the second swing gear 19B make one turn. As a result, the rotation of the crankshaft 18 is significantly decelerated and transmitted to the outer cylinder 17. In addition, in this embodiment, since the eccentric parts 18a and 18b of each crankshaft 18 are eccentric so as to be shifted by 180 degrees from each other around the axis, the rotation phase of the first swing gear 19A and the second swing gear 19B is will be shifted by 180°.

A perforated disk-shaped output plate 26 is attached to the end of the outer cylinder 17 opposite to the fixed block (lower end in FIG. 1). The output plate 26 covers the end (lower side in FIG. 1) of the second carrier block 15B in a non-contact manner. A rotated body can be attached to the axially outer end surface of the output plate 26 by bolting or the like. Further, the output plate 26 has a cylinder on the inner circumference that passes through each inner circumference of the second carrier block 15B, the second swing gear 19B, the first swing gear 19A, and the first carrier block 15A in a non-contact state. 27 is attached.

A central gear 30 is rotatably supported by the first carrier block 15A via a bearing 35B. The central gear 30 rotates under the rotation of a rotational drive source (not shown). External teeth 30a are formed on the outer periphery of the central gear 30.

Further, the end portion of each crankshaft 18 passes through the first carrier block 15A in the axial direction. A crankshaft gear 31 is attached to the end of each crankshaft 18 passing through the first carrier block 15A. The tooth surface 31a of each crankshaft gear 31 meshes with the external tooth 30a of the central gear 30. When power from the rotational drive source is input to the central gear 30, the rotation is transmitted to each crankshaft 18 via the crankshaft gear 31. In this way, when each crankshaft 18 rotates, the first oscillating gear 19A and the second oscillating gear 19B rotate as described above, and the rotation reduced to the set reduction ratio is transmitted via the outer cylinder 17 and the output plate 26. It is transmitted to the rotated body.

FIG. 3 is a view of the reducer 10 shown in FIG. 2 in the direction of arrow III.
As shown in FIG. 3, each pin groove 60 on the inner circumference of the outer cylinder 17 is formed in a substantially arc shape so that the outer circumferential surfaces of the corresponding internal pins 20A, 20B are slidably abutted. At the left and right edges of each pin groove 60 in a direction orthogonal to the longitudinal direction, holding protrusions 62 are formed that protrude from the edges toward the radial inner side of the outer cylinder 17. The holding protrusions 62 on the left and right edges rotatably hold the corresponding internal pins 20A, 20B together with the pin groove 60. The pin groove 60 and the holding protrusions 62 on the left and right sides of the pin groove 60 continuously cover an area A1 of more than half of the circular cross section of the corresponding internal pins 20A, 20B in a direction orthogonal to the axial direction in an arc shape. It is formed like this. A protruding end 62a of the holding protrusion 62 on the radially inner side of the outer cylinder 17 is formed into a curved shape so as to avoid edge contact with the internally toothed pins 20A, 20B.
In the case of this embodiment, the holding protrusion 62 is formed continuously over almost the entire length of each pin groove 60 in the longitudinal direction.

In the present embodiment, the pin holding mechanism includes internal pins 20A and 20B (pins) and an outer cylinder 17 (case) that holds the internal pins 20A and 20B with pin grooves 60 on the inner circumferential side. ing. The holding protrusion 62 formed on the edge of the pin groove 60 of the outer cylinder 17 constitutes a drop-off prevention means for preventing the internal pins 20A, 20B from falling off.

As described above, in the reducer 10 of this embodiment, the holding protrusions 62 that rotatably hold the corresponding internal pins 20A and 20B are formed on the left and right side edges of each pin groove 60 of the outer cylinder 17. has been done. Therefore, when the first and second oscillating gears 19A and 19B rotate, the first oscillating gear 19A and the second oscillating gear 19B are separated from the inner peripheral surface of the outer cylinder 17 by a large distance, as shown in FIG. Even if this happens, the retaining protrusion 62 can prevent the internally toothed pins 20A, 20B from coming out of the pin groove 60. Therefore, it is possible to suppress the entire internal pins 20A, 20B from being displaced or tilted in the direction of the first swing gear 19A and the second swing gear 19B. Therefore, when the reducer 10 of this embodiment is adopted, the axial ends of the internal pins 20A and 20B are strongly attached to the external teeth 19Aa and 19Ba of the first swing gear 19A and the second swing gear 19B. It is possible to prevent damage to the external teeth 19Aa, 19Ba due to contact, and to stabilize the operation of the speed reducer 10 by reducing the behavior of the internal pins 20A, 20B.

Further, in the pin holding mechanism employed in the reducer 10 of this embodiment, a holding protrusion 62, which is a means for preventing falling off, is provided in the pin groove 60 of the outer cylinder 17, which is a holding member. Therefore, when the pin holding mechanism of this embodiment is adopted, the internally toothed pins 20A, 20B can be prevented from falling out from the pin groove 60, and the internally toothed pins 20A, 20B can behave unstablely within the pin groove 60. can be suppressed.

Furthermore, in the reducer 10 of this embodiment, the displacement of the internal pins 20A and 20B from the pin groove 60 is regulated by the holding protrusion 62, so as shown in FIG. When the second rocking gear 19B is largely separated from the inner circumferential surface of the outer cylinder 17, some of the internal pins 20A, 20B touch the external teeth 19Aa, 19Ba of the first and second rocking gears 19A, 19B. There will be no contact. At this time, some of the internal pins 20A, 20B stop rolling, and heat generation due to rolling friction is suppressed. Therefore, when this configuration is adopted, it is possible to suppress the heat generated due to the operation of the reducer 10.

In particular, in the reducer 10 of the present embodiment, the pin groove 60 and the holding protrusion 62 protruding from the side edge thereof are more than half of the circular cross section of the internal pins 20A, 20B in the direction orthogonal to the axial direction. It is formed to cover area A1 in an arc shape. Therefore, while allowing the internal pins 20A, 20B to rotate, the holding protrusion 62 can reliably restrict the displacement of the internal pins 20A, 20B in the direction of the first and second rocking gears 19A, 19B. can.

In the case of the reducer 10 of this embodiment, a pair of pins are provided in each pin groove 60 of the outer cylinder 17 so as to mesh independently with each of the external teeth 19Aa and 19Ba of the first and second rocking gears 19A and 19B. Internally toothed pins 20A and 20B are arranged. Therefore, when the external teeth of one of the first oscillating gear 19A and the second oscillating gear 19B are pressing the internal pin, the pressing force applied to the internal pin is applied to the other external tooth. can be prevented from working. Therefore, it is possible to prevent unnecessary resistance friction from occurring during the operation of the reducer 10 and heating the reducer 10 due to frictional heat.
When the internal pins 20A, 20B are not engaged across the external teeth 19Aa of the first oscillating gear 19A and the external teeth 19Ba of the second oscillating gear 19B, the internal pins 20A, 20B are Although it becomes easy to separate from 19Aa and 19Ba, in the case of this embodiment, the displacement of each internal tooth pin 20A and 20B in the falling direction can be reliably regulated by the holding protrusion 62.

Note that the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the gist thereof.
For example, in the above embodiment, the carrier (first carrier block 15A and second carrier block 15B) is fixed and the outer cylinder 17 rotates as an output rotating body, but conversely, the outer cylinder 17 is fixed. A configuration may also be adopted in which the carrier (first carrier block 15A and second carrier block 15B) rotates as an output rotating body.

Furthermore, in the above embodiment, two rocking gears (first rocking gear 19A, second rocking gear 19B) that rotate and mesh with the internal pins 20A, 20B of the outer cylinder 17 are provided. , the number of rocking gears is not limited to two, but is arbitrary.

Further, in the pin holding mechanism and reduction gear of the above embodiment, the internal pins 20A, 20B are held on the inner periphery of the outer cylinder 17, which is the holding member (case), and the internal pins 20A, 20B are The external teeth 19Aa and 19Ba of the first and second rocking gears 19A and 19B can mesh with each other. However, a pin groove is formed on the outer periphery of the holding member (case), an externally toothed pin is held in the pin groove, and a swing gear having internal teeth is rotatably arranged on the outer periphery of the holding member. It is also possible to mesh the internal teeth of the oscillating gear with the external pin.

Further, in the above embodiment, the holding protrusion 62 (protrusion) serving as a drop-off prevention means is integrally formed on the edge of the pin groove 60, but a separate holding protrusion 62 (protrusion) having a function of preventing the pin from falling off from the pin groove 60 is also provided. It is also possible to attach means for preventing the body from falling off at the edge of the pin groove 60. Further, in the above embodiment, the holding protrusions 62 constituting the falling-off prevention means are arranged on both left and right edges of the pin groove 60, but the falling-off preventing means is arranged only on one edge of the pin groove. It is also possible.

DESCRIPTION OF SYMBOLS 10... Reduction gear , 17... Outer cylinder ( case), 19A... 1st rocking gear (rocking gear), 19B... 2nd rocking gear (rocking gear), 19Aa, 19Ba... External tooth, 20A, 20B... Internal tooth pin, 60...pin groove, 62...retaining protrusion

Claims (2)

a case having a plurality of pin grooves extending in the axial direction on the inner circumference;
an internally toothed pin disposed in each of the plurality of pin grooves;
The external teeth have a smaller number of teeth than the number of grooves in the pin groove, are arranged in line in the axial direction inside the case, and are engaged with the corresponding internal tooth pin in the pin groove in response to input rotation. A plurality of swinging gears that rotate,
a holding protrusion that protrudes inward in the radial direction of the case from an edge in a direction perpendicular to the longitudinal direction of each of the pin grooves and prevents each of the internally toothed pins from falling off;
A plurality of internally toothed pins are arranged in each of the pin grooves so as to independently mesh with the external teeth of each of the rocking gears , and the holding protrusion covers almost the entire length of each of the pin grooves in the longitudinal direction. A speed reducer that is formed continuously . According to claim 1, the holding protrusion holds the internal tooth pin in a non-contact state with respect to the external teeth of the rocking gear when the rocking gear is largely separated from the inner circumferential surface of the case. The speed reducer mentioned.

Images