JP6932068B2 - Eccentric swing type gear device - Google Patents

Description

The present invention relates to an eccentric swing type gear device.

Patent Document 1 describes an internal gear, an external gear that meshes internally with the internal gear, an eccentric body that swings the external gear, and a carrier body that is arranged on the axial side of the external gear. An eccentric swing type gear device comprising the above is disclosed. In the conventional eccentric swing type gear device, as shown in Patent Document 1, an internal gear is provided in the casing, and the carrier body is rotatably supported with respect to the casing via a main bearing.

Japanese Unexamined Patent Publication No. 07-248046

In the conventional eccentric swing type gear device, it is generally assumed that the spindle receives a large proportion of the load applied from the outside of the device and the load generated inside the device. Therefore, in the conventional eccentric swing type gear device, a large spindle is adopted, which causes a problem that the size of the entire device is increased.

An object of the present invention is to provide an eccentric swing type gear device capable of reducing the size.

The present invention
A casing provided with an internal gear, an external gear that meshes internally with the internal gear, an eccentric shaft having an eccentric body that swings the external gear, and an input bearing that supports the eccentric shaft. An eccentric swing type gear device including a carrier body arranged on the axial side portion of the external gear and a main bearing arranged between the casing and the carrier body.
In a cross section perpendicular to the circumferential direction rather smaller than the cross-sectional area of the cross-sectional area is the input bearing of the main bearing,
A plurality of internal pins connected to the carrier body, penetrating the entire axial direction of the internal pin holes of the external gear, and synchronizing with the rotation component of the external gear are provided.
The outer diameter of the main bearing has a structure not smaller than the inscribed circle diameter of the plurality of inner pins.

According to the present invention, the effect that the size of the eccentric swing type gear device can be reduced can be obtained.

It is sectional drawing of the eccentric swing type gear device which concerns on embodiment of this invention. It is a figure which looked at the inside of the eccentric swing type gear apparatus of FIG. 1 from the axial direction. It is a figure explaining the adjustment process of an inner pin.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a cross-sectional view of an eccentric swing type gear device according to an embodiment of the present invention. FIG. 2 is a view of the inside of the eccentric swing type gear device of FIG. 1 as viewed from the axial direction. In the present specification, the direction along the rotation axis O1 of the eccentric swing type gear device 1 is defined as the axial direction, the direction perpendicular to the rotation axis O1 is defined as the radial direction, and the rotation direction centered on the rotation axis O1 is defined as the circumferential direction. ..

The eccentric swing type gear device 1 includes an eccentric body 14, an eccentric body shaft 12 having the eccentric body 14, an external gear 24 incorporated on the outer periphery of the eccentric body 14 via an eccentric bearing 18, and an external gear. It is provided with an internal gear 26 in which 24 is engaged while swinging. Further, the eccentric swing type gear device 1 holds a plurality of inner pins 28 that engage with the external gear 24 and a plurality of inner pins 28, and the first carrier body 33 and the second carrier body that take out the revolution motion thereof. With 34. In addition, the eccentric swing type gear device 1 includes a first casing 31 and a second casing 32 connected to the internal gear 26, a first spindle bearing 36, a second spindle bearing 38, a first input bearing 40, and a second. The input bearing 42 is provided. Of these, the first casing 31, the second casing 32, and the internal gear body 26A (described later) correspond to an example of the casing according to the present invention. The first input bearing 40 and the second input bearing 42 correspond to an example of the input bearing according to the present invention. The first carrier body 33 and the second carrier body 34 correspond to an example of the carrier body according to the present invention. The first headstock 36 and the second headstock 38 correspond to an example of the headstock according to the present invention.

Among the above components, the first casing 31, the first carrier body 33, the first spindle bearing 36, and the first input bearing 40 are one of the axial directions (right side in FIG. 1, input side) with respect to the external gear 24. ) Is placed. The second casing 32, the second carrier body 34, the second main bearing 38, and the second input bearing 42 are arranged on the other side (left side in FIG. 1, load side) in the axial direction with respect to the external gear 24.

The eccentric body axis 12 rotates about the rotation axis O1. The eccentric shaft 12 typically functions as an input shaft for inputting rotational motion from the outside of the device, and for example, a tap hole T1 is used to connect a member on the input side such as a gear, a shaft joint, or a pulley. Instead of the tap hole T1, it may be connected by a key. The radial load generated on the gears and pulleys is supported by the first input bearing 40 and the second input bearing 42.

The outer peripheral surface of the eccentric body 14 has a curved surface shape on the side surface of a cylinder, and the central axis of the outer peripheral surface is eccentric from the rotation axis O1. The eccentric body 14 is connected to the eccentric body shaft 12 so as not to rotate relative to the eccentric body shaft 12 by, for example, a key connection or a D cut, and rotates about the rotation shaft O1.

The external gear 24 is swingably incorporated into the outer periphery of the eccentric body 14 via the eccentric bearing 18, and is inscribed and meshed with the internal gear 26. The external gear 24 has a plurality of inner pin holes 246 at positions offset from the axis (see FIGS. 1 and 2), and the plurality of inner pins 28 are a part of the inner peripheral surface of the inner pin holes 246. It is penetrated in contact with. Further, the external gear 24 has a plurality of through holes 248 at positions offset from the axis (see FIGS. 1 and 2), and a plurality of connecting pins 29 are penetrated therethrough. Further, the external gear 24 is provided with a trochoidal corrugated tooth portion 243 (see FIG. 2) on the outermost peripheral portion. FIG. 2 shows a state in which the first casing 31, the first carrier body 33, the first spindle bearing 36, the first input bearing 40, and the eccentric body shaft 12 are removed, as viewed from the right side of FIG. Further, in the external gear 24 of the present embodiment, in addition to the inner pin hole 246 and the through hole 248, three punch holes 247 through which no member is inserted are formed to reduce the weight.

The first carrier body 33 and the second carrier body 34 are arranged on one side and the other side, which are axial side portions of the external gear 24, respectively, and hold a plurality of inner pins 28. The plurality of inner pins 28 are connected to the first carrier body 33 and the second carrier body 34 by clearance fitting. Further, the first carrier body 33 and the second carrier body 34 are firmly coupled to each other by tightly fitting (for example, shrink fitting) a plurality of connecting pins 29. The connecting pin 29 does not come into contact with the inner peripheral surface of the through hole 248 of the external gear 24 and does not have a function of extracting the rotational movement of the external gear 24. The second carrier body 34 typically functions as an output shaft that outputs a decelerated rotational motion.

The inner pin 28 has a diameter (thickness) from a portion held by the first carrier body 33 to a portion held by the second carrier body 34, sandwiching a portion passing through the inner pin hole 246 of the external gear 24. Are the same. With such a shape, the inner pin 28 can be manufactured with high molding accuracy and at low cost. When the second carrier body 34 functions as an output shaft, the inner pin 28 transmits the rotation component of the external gear 24 to the second carrier body 34. Further, the inner pin 28 regulates the rotation of the external gear 24 when the second carrier body 34 is fixed and the casing functions as an output shaft. That is, the inner pin 28 synchronizes with the rotation component of the external gear 24.

The internal gears 26 are integrally connected to the first casing 31 and the second casing 32, and form a part of the casing. The internal gear main body 26A and a plurality of internal gears 26 provided on the inner peripheral portion of the internal gear main body 26A. Has a pin groove 26C and a plurality of outer pins 26B rotatably supported by each of the plurality of pin grooves 26C. The internal gear main body 26A is detachably connected to the first casing 31 and the second casing 32 by using a fastening member B1 such as a bolt. Here, the casing of the present invention may be a member as long as it is provided with internal gears and supports the carrier body via a main bearing, and a plurality of members may be connected to each other to form a single member. It may be configured. The number of internal teeth of the internal gear 26 (the number of external pins 26B) is slightly different from the number of external teeth of the external gear 24 (for example, one more). The internal gear 26 and the external gear 24 are meshed with the plurality of external pins 26B in contact with the tooth portions 243 of the external gear 24 (see FIG. 2).

The first main bearing 36 is provided between the first carrier body 33 and the first casing 31. The second main bearing 38 is provided between the second carrier body 34 and the second casing 32. As a result, the first carrier body 33 and the second carrier body 34 are rotatably supported with respect to the first casing 31 and the second casing 32. The first main bearing 36 and the second main bearing 38 are clearance-fitted to the first casing 31 and the second casing 32, respectively, and are tightly fitted to the first carrier body 33 and the second carrier body 34, respectively. The first spindle bearing 36 and the second spindle bearing 38 are, for example, ball bearings. The fitting force of the first main bearing 36 and the second main bearing 38 to the first casing 31 and the second casing 32 may be weaker than the fitting force to the first carrier body 33 and the second carrier body 34. For example, an intermediate fit may be used.

The first input bearing 40 is provided between the eccentric body shaft 12 and the first carrier body 33. The second input bearing 42 is provided between the eccentric body shaft 12 and the second carrier body 34. As a result, the eccentric body shaft 12 is rotatably supported with respect to the first carrier body 33 and the second carrier body 34. The first input bearing 40 and the second input bearing 42 are, for example, ball bearings.

<Size and arrangement of bearings>
In the cross section orthogonal to the circumferential direction, each of the first spindle bearing 36 and the second spindle bearing 38 has a smaller cross-sectional area than each of the first input bearing 40 and the second input bearing 42. The eccentric body bearing 18 has a larger cross-sectional area than each of the first input bearing 40 and the second input bearing 42 in a cross section orthogonal to the circumferential direction. The cross-sectional area of the bearing refers to the area of the range including the outer ring of the bearing, the inner ring, and the gap between the outer ring and the ring on which the rolling element and the cage of the rolling element are arranged. In other words, it refers to the area of the outer peripheral surface of the outer ring, the inner peripheral surface of the inner ring, the side surface of the outer ring and its extension line, and the area of a substantially rectangular shape (substantially square) surrounded by the side surface of the inner ring and its extension line.

The first spindle bearing 36 and the first input bearing 40 are provided at positions where they overlap each other when viewed in the radial direction. The second main bearing 38 and the second input bearing 42 are provided at positions where they overlap each other when viewed in the radial direction.

The inner diameter of each of the first spindle bearing 36 and the second spindle bearing 38 is larger than the outer diameter of each of the first input bearing 40 and the second input bearing 42, and is larger than the outer diameter of the eccentric body bearing 18. The outer diameter φ1 (see FIG. 1) of each of the first headstock 36 and the second headstock 38 is smaller than the inscribed circle diameter φ2 (see FIG. 2) of the plurality of inner pins 28.

<Inner pin adjustment>
FIG. 3 is a diagram illustrating an adjustment process of the inner pin.

In the eccentric swing type gear device 1, a plurality of types of inner pins 28 having slightly different outer diameters are prepared at the time of assembly, and the inner pin 28 having the most suitable diameter is applied to greatly reduce backlash. be able to. The selection of the inner pin 28 having the most suitable diameter is performed as follows.

First, the worker assembles the eccentric swing type gear device 1 using an arbitrary inner pin 28, and measures backlash and the like. As a result, if the predetermined performance is not obtained, the operator removes the first casing 31 or the second casing 32 as shown in FIG. As a result, the ends of the plurality of inner pins 28 can be exposed. At this time, the first spindle bearing 36 and the second spindle bearing 38 are left behind in the first carrier body 33 and the second carrier body 34 that are tightly fitted. However, since the outer diameters of the first headstock 36 and the second headstock 38 are smaller than the inscribed circle diameters of the plurality of inner pins 28, the first headstock 36 and the second headstock 38 are inserted and removed from the inner pins 28. Does not hinder. Such an action is similarly obtained on both sides in the axial direction.

In this state, the worker inserts and removes the plurality of inner pins 28 to change to another inner pin 28, fixes the first casing 31 and the second casing 32 again, and measures backlash and the like. By repeating such processing, the inner pin 28 having the optimum performance can be selected.

Further, when the inner pin 28 is inserted and removed, if the difference between the diameter of the inner pin 28 and the hole diameters of the first carrier body 33 and the second carrier body 34 becomes small, it is difficult to insert and remove the inner pin 28 from one side. May occur. In such a case, the inner pin 28 can be changed by pulling out or inserting the inner pin 28 from the opposite side.

<Operation of eccentric swing type gear device>
Subsequently, the operation of the eccentric swing type gear device 1 will be described. When the eccentric body shaft 12 rotates, the eccentric body 14 rotates eccentrically and the external gear 24 swings. The external gear 24 is inscribed in mesh with the internal gear 26, and in this embodiment, the internal gear 26 is integrated with the first casing 31 and the second casing 32. Therefore, the external gear 24 rotates (rotates) relative to the internal gear 26 by the difference in the number of teeth each time the eccentric shaft 12 rotates once. The rotation component of the external gear 24 is transmitted to the first carrier body 33 and the second carrier body 34 via the inner pin 28 penetrating the inner pin hole 246. As a result, the rotational movement of the eccentric body shaft 12 is decelerated by the reduction ratio of "1 / the number of teeth of the external gear 24", and is output as the rotation of the first carrier body 33 and the second carrier body 34.

<Effect of embodiment>
As described above, according to the eccentric swing type gear device 1 of the present embodiment, the cross-sectional areas of the first spindle bearing 36 and the second spindle bearing 38 are each of the first input bearing 40 and the second input bearing 42. It is smaller than the cross-sectional area. Therefore, the size of the entire device can be reduced as compared with the case where the cross-sectional areas of the first headstock 36 and the second headstock 38 are increased, and in particular, the size in the axial direction is reduced, that is, the eccentric swing type gear device 1. Can be flattened. Furthermore, weight reduction is also achieved by flattening. Generally, if the material and structure of the bearing are the same, the durability is higher when the cross-sectional area is larger and when the diameter is larger and the number of rolling elements is larger. Further, the deterioration of the bearing progresses as the load increases and the total number of rotations increases. The first input bearing 40 and the second input bearing 42 receive a high-speed rotation of the eccentric body shaft 12, whereas the first spindle bearing 36 and the second spindle bearing 38 receive a low-speed rotation after deceleration. Further, the first spindle bearing 36 and the second spindle bearing 38 are longer in the circumferential direction than the first input bearing 40 and the second input bearing 42. Therefore, even if the cross-sectional area of the first spindle bearing 36 and the second spindle bearing 38 is reduced as described above, the first spindle bearing 36 and the second spindle bearing 38, the first input bearing 40, and the second input bearing 42 The balance of durability is not lost. Therefore, the flattening of the eccentric swing type gear device 1 can be realized while maintaining the balance of durability of each bearing.

Further, according to the present embodiment, the outer diameter φ1 of the first main bearing 36 and the second main bearing 38 is smaller than the inscribed circle diameter φ2 of the plurality of inner pins 28. As a result, when the first casing 31 and the second casing 32 are removed, the inner pin 28 can be inserted and removed without removing the first main bearing 36 and the second main bearing 38. Further, according to this configuration, after assembling the first carrier body 33 and the first main bearing 36, this can be assembled to the eccentric body shaft 12. Further, after assembling the second main bearing 38 to the second carrier body 34, this can be assembled to the eccentric body shaft 12. If it is necessary to assemble the first main shaft 36 and the second main shaft 38 after assembling the first carrier body 33 and the second carrier body 34 to the eccentric body shaft 12, workability will deteriorate. Depending on the configuration, it is not necessary to take such a procedure, and workability is significantly improved.

Further, according to the eccentric swing type gear device 1 of the present embodiment, the first carrier body 33 and the second carrier body 34 are arranged on one side and the other side of the external tooth gear 24. Further, on both sides in the axial direction, the relationship between the outer diameters of the first spindle bearing 36 and the second spindle bearing 38 and the inscribed circle diameter of the inner pin 28 is established. With such a configuration, when the first casing 31 and the second casing 32 are removed, the inner pin 28 can be inserted and removed in both axial directions. As a result, even if the inner pin 28 is difficult to insert or remove from one of the axial directions, the inner pin 28 can be incorporated by inserting and removing the inner pin 28 from the opposite direction of the axial direction without making the inner pin 28 into a special shape. The possibility can be increased. For example, the speed reducer of FIG. 1 of Patent Document 1 has a structure in which the inner pins cannot be inserted and removed from both sides in the axial direction. Therefore, the inner pins have a stepped structure so that the inner pins can be reliably inserted and removed from one side. However, the manufacturing cost of the inner pin having such a stepped structure is very high.

Further, according to the present embodiment, the cross-sectional area of the eccentric body bearing 18 is larger than the cross-sectional area of the first input bearing 40 and the second input bearing 42. The eccentric body bearing 18 receives an internal load generated by the meshing of the internal gear 26 and the external gear 24. Further, while the first input bearing 40 and the second input bearing 42 support the eccentric body shaft 12 at two points, the eccentric body bearing 18 supports the external gear 24 and the eccentric body 14 at one point. Therefore, by increasing the cross-sectional area of the eccentric body bearing 18 and increasing the load capacity as compared with the first input bearing 40 and the second input bearing 42, the first input bearing 40, the second input bearing 42 and the eccentricity are increased. The balance of the load capacity of the body bearing 18 can be improved.

Further, according to the present embodiment, the first spindle bearing 36 and the first input bearing 40 are arranged so as to overlap each other when viewed from the radial direction, and the second spindle bearing 38 and the second input bearing 42 are arranged so as to be viewed from the radial direction. They are arranged so as to overlap each other. From the viewpoint of flattening the entire device, the first spindle bearing 36 and the second spindle bearing 38 are flattened when arranged outside the first input bearing 40 and the second input bearing 42 in the axial direction. However, it is not very effective even if it is placed inward. This is because the size in the axial direction is determined by the first input bearing 40 and the second input bearing 42. Further, the radial load is smaller when it is received at a place where the distance from the fulcrum is large. Therefore, by arranging the first spindle 36 and the second spindle 38 as described above, the first spindle 36 and the second spindle are provided by a radial load from the outside without hindering the flattening of the entire device. The load applied to 38 can be reduced. Therefore, with the above arrangement, the first spindle bearing 36 and the second spindle bearing 38 and the first spindle bearing 36 and the first spindle bearing 36 and the second spindle bearing 42 without disturbing the balance of durability of the first input bearing 40 and the second input bearing 42. The cross-sectional area of the second spindle 38 can be made smaller. As a result, the eccentric swing type gear device 1 can be made flatter.

Further, in general, the eccentric swing type gear device 1 connects a moving portion to a second carrier body 34 that functions as an output shaft via a gear, a sprocket, a shaft joint, or the like to drive the moving portion, or a first. It is used to connect an arm to the two-carrier body 34 and move it. However, in all of these usage modes, a large radial load is not always generated in the eccentric swing type gear device 1. For example, when a shaft joint is connected, the radial load becomes zero, and when a large-diameter gear, sprocket, and arm are connected, the second carrier even if the torque applied to them is the same. The radial load applied to the body 34 becomes smaller. In the case of such a usage pattern, if an eccentric swing type gear device using a large spindle as in the conventional case is used, the configuration size of the reduction gear becomes large, which hinders the miniaturization of the drive device. Become. However, in the case of such a usage pattern, by using the eccentric swing type gear device 1 of the present embodiment, it is possible to contribute to the miniaturization of the drive device at a large rate.

The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiment. For example, in the above embodiment, a configuration having two carrier bodies, two input bearings, and two main bearings on one side and the other side in the axial direction is shown. However, only one carrier body may be provided on one side in the axial direction. A pair of spindle bearings may be arranged on one carrier body, or may be one spindle bearing, for example, by adopting a cross roller bearing. Further, the number of input bearings may be one when a cross roller bearing is adopted or when the bearing is supported in cooperation with the bearing of the motor shaft. Further, the plurality of input bearings arranged on one side and the other side in the axial direction do not have to have the same diameter, and the plurality of main bearings arranged on one side and the other side in the axial direction do not have to have the same diameter. Further, in the above embodiment, the outer diameter of the spindle is smaller than the inscribed circle diameter of the plurality of inner pins, which has the effect of facilitating the adjustment work of the inner pins. , Such a configuration does not have to be applied. Even in that case, the effect of being able to flatten the eccentric swing type gear device is achieved. Further, in the above embodiment, a shield bearing having a sealing function is used for the input bearing and the main bearing, but a bearing having no sealing function may be used and an oil seal may be separately arranged.

Further, in the above embodiment, a so-called center crank type eccentric swing type speed reducer in which one eccentric body shaft is arranged at the shaft center of the speed reducer is shown. However, the present invention may be applied to a so-called distribution type eccentric swing type reduction gear in which two or more eccentric body shafts are arranged offset from the axis of the speed reducer. In addition, the details shown in the embodiment, such as the type of bearing and the number of external gears, can be appropriately changed without departing from the spirit of the invention.

1 Eccentric swing type gear device 12 Eccentric body shaft 14 Eccentric body 24 External gear 26 Internal gear 26A Internal gear body 26B External pin 26C Pin groove 28 Internal pin 29 Connecting pin 31 First casing 32 Second casing 33 First Carrier body 34 2nd carrier body 36 1st spindle bearing 38 2nd spindle bearing 40 1st input bearing 42 2nd input bearing 246 Inner pin hole 248 Through hole

Claims (5)

A casing provided with an internal gear, an external gear that meshes internally with the internal gear, an eccentric shaft having an eccentric body that swings the external gear, and an input bearing that supports the eccentric shaft. An eccentric swing type gear device including a carrier body arranged on the axial side portion of the external gear and a main bearing arranged between the casing and the carrier body.
In a cross section perpendicular to the circumferential direction rather smaller than the cross-sectional area of the cross-sectional area is the input bearing of the main bearing,
A plurality of internal pins connected to the carrier body, penetrating the entire axial direction of the internal pin holes of the external gear, and synchronizing with the rotation component of the external gear are provided.
The outer diameter of the spindle is smaller than the inscribed circle diameter of the plurality of inner pins.
Eccentric swing type gear device. The casing has an internal gear body on which the internal gear is formed, and a first casing that is supported by the main bearing and covers the internal pin from the axial direction.
The eccentric swing type gear device according to claim 1, wherein the inner pin can be inserted into and removed from the external gear while the first casing is removed and the main bearing is arranged on the carrier body. The carrier body includes a first carrier body arranged on one side in the axial direction of the external gear and a second carrier body arranged on the other side in the axial direction of the external gear.
The spindle includes a first spindle that supports the first carrier body and a second spindle that supports the second carrier body.
The outer diameters of both the first spindle and the second spindle are smaller than the inscribed circle diameters of the plurality of inner pins.
The eccentric swing type gear device according to claim 2. An eccentric bearing provided between the eccentric body and the external gear.
The cross-sectional area of the eccentric bearing is larger than the cross-sectional area of the input bearing in the cross section perpendicular to the circumferential direction.
The eccentric swing type gear device according to any one of claims 1 to 3. The casing further has a second casing that is located on the opposite side of the first casing with respect to the external gear and covers the inner pin from the axial direction.
The eccentric swing type gear device according to claim 2, wherein the inner pin can be inserted into and removed from the external gear while the second casing is removed and the main bearing is arranged on the carrier body.

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