JP5188889B2 - Decelerator - Google Patents

Description

  The present invention relates to a reduction gear having a heat dissipation structure and a method of manufacturing an input shaft thereof.

  Conventionally, an input shaft, an eccentric body provided on the input shaft, an external gear provided outside the eccentric body, and an internal gear internally meshing with the external gear, the external teeth A speed reducer that takes out relative rotation between a gear and an internal gear as an output is known (see, for example, Patent Document 1). In such a speed reducer, when the input shaft rotates, the eccentric body provided on the input shaft rotates together with the input shaft. Then, the external gear provided on the outer side of the eccentric body performs a swinging motion via the eccentric body bearing provided on the inner side thereof. Then, the external gear that swings and engages with the internal gear, and the relative rotation between the external gear and the internal gear that is generated by meshing with the internal gear is output.

  In the field of this type of reducer, miniaturization and high output are progressing.

JP 2001-187945 A

  In the case of the speed reducer as described above, heat is generated by sliding and meshing of each part. The problem of heat generation is most severely concentrated in the vicinity of the input shaft that rotates at high speed and the eccentric body provided in the reduction gear of this type. This heat generation greatly affects the durability of the reduction gear, and becomes an obstacle to downsizing and high output of the reduction gear.

  The present invention has been made to solve such a problem, and in a speed reducer having an input shaft and an eccentric body provided on the input shaft, the structural features of the input shaft can be increased by providing structural features. The purpose is to make it possible to efficiently dissipate heat generated by rotation.

  The present invention includes an input shaft, an eccentric body provided on the input shaft, an external gear provided on the outer side in the radial direction of the eccentric body, and an internal gear internally meshing with the external gear. A reduction gear that takes out the relative rotation between the external gear and the internal gear as an output, wherein the input shaft has a hollow portion in the center in the radial direction, and the eccentric body is integrated with the input shaft. A recess is provided over the entire circumference at an axial position including the axial position where the eccentric body is formed on the hollow portion side of the input shaft. The above-mentioned problem is solved by inclining with respect to a plane perpendicular to the axis of the input shaft.

  As a result of adopting such a configuration, the surface area in the vicinity of the eccentric body on the hollow portion side of the input shaft increases more than when there is no recess. For this reason, it becomes possible to reduce a thermal resistance and the heat dissipation effect in a hollow part increases.

  Further, by forming the recess, the amount of metal in the portion constituted by the input shaft and the eccentric body is reduced, so that the heat radiation effect near the recess can be further increased and the weight can be reduced. .

  In the present invention, in order to maximize this effect, the eccentric body is intentionally formed integrally with the input shaft, and as a result, the concave portion is formed in the thickened portion. Therefore, a deep recess can be formed without reducing the strength, and a great heat dissipation effect and weight reduction effect can be exhibited.

  Furthermore, the recess according to the present invention is set so that the cut ridge line is inclined with respect to the axis of the input shaft, and therefore, processing is easy and larger than (which is an inclined ridge line). A heat radiation area can be easily secured. Further, since the vicinity of the end portion of the bottom surface of the recess has an “obtuse angle”, stress concentration can be reduced.

  The present invention relates to an input shaft having a hollow portion, an eccentric body provided on the input shaft, an external gear provided on the radially outer side of the eccentric body, and an internal tooth that is in mesh with the external gear. In the method of manufacturing the input shaft of the speed reducer that takes out relative rotation between the external gear and the internal gear as an output, the hollow body side of the input shaft, and the eccentric body is formed. In forming the concave portion over the entire circumference in the axial position including the axial position, the inner diameter of the hollow portion of the input shaft is gradually increased from the position corresponding to the end portion of the concave portion along the axial direction. Thus, it can also be regarded as a method for manufacturing an input shaft of a reduction gear, comprising a first cut ridge line forming step for forming the first cut ridge line of the recess.

  ADVANTAGE OF THE INVENTION According to this invention, in the reduction gear which has an eccentric body, it becomes possible to thermally radiate the heat which generate | occur | produces near an eccentric body by rotation of an input shaft efficiently.

  Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 2 is a side sectional view of a reduction gear according to an example of an embodiment of the present invention, and FIG. 1 is an enlarged view of a main part of FIG.

  The speed reducer 100 is provided radially outside the input shaft 102, the first and second eccentric bodies 104A and 104B provided integrally with the input shaft 102, and the first and second eccentric bodies 104A and 104B. The first and second external gears 108 and 110 and the internal gear 122 that is in mesh with the first and second external gears 108 and 110 are provided. The input shaft 102 has a hollow portion 102A having an inner diameter D1, and a recess 102B is formed corresponding to the axial position where the first and second eccentric bodies 104A and 104B are formed. This will be described in detail below.

  The input shaft 102 is rotatably supported by a bearing 142 disposed in the vicinity of the second eccentric body 104B and a bearing disposed in a motor (not shown).

  The outer circumferences of the first and second eccentric bodies 104A and 104B are eccentric with respect to the axis O of the input shaft 102 so that the phases are different by about 180 °. The first and second external gears 108 and 110 are fitted to the outer circumferences of the first and second eccentric bodies 104A and 104B via first and second eccentric body bearings (rollers) 106A and 106B. . The first and second external gears 108 and 110 are in mesh with the internal gear 122.

  The internal teeth of the internal gear 122 are constituted by cylindrical outer pins 116. The number of teeth of the internal gear 122 (the number of external pins 116) is slightly larger (about 1 to 3) than the number of teeth of the first and second external gears 108 and 110.

  The first and second external gears 108 and 110 are provided with a plurality of inner pin holes 108A and 110A in the axial direction. The inner pin 112 is loosely fitted to the inner pin holes 108A and 110A via the inner roller 114. Further, first and second flanges 118 and 124 are arranged on both sides in the axial direction of the first and second external gears 108 and 110. From the first flange 118, the inner pin 112 is integrally formed so as to be cantilevered.

  On the outermost side in the radial direction of the first flange 118, the frame body 120 is connected and fixed by bolts 127 (only bolt holes are shown in FIG. 1). The frame body 120 also serves as a casing for the speed reducer 100. The frame body 120 and the internal gear 122 are relatively rotatable via a cross roller bearing 128. On the other hand, the second flange 124 rotatably supports the input shaft 102 via the bearing 142. The second flange 124 is connected and fixed integrally with the internal gear 122 via a bolt 126.

  In addition, the code | symbol 130, 144, 146 of a figure has shown the 1st-3rd seal member, and the code | symbol 148 has shown O-ring, respectively. The inside of the speed reducer 100 is sealed by the first to third seal members 130, 144, 146 and the O-ring 148. The speed reducer 100 is used, for example, for driving a robot joint by mounting a flat motor (not shown) on the input shaft 102 and coupling it. In the present invention, the types of motors to be combined are not particularly limited, and illustration and detailed description of the motor portion are omitted.

  Here, the recess 102B formed in the input shaft 102 will be described in detail.

  The input shaft 102 is integrally formed with first and second eccentric bodies 104A and 104B. The portions of the input shaft 102 adjacent to the first and second eccentric bodies 104A and 104B in the axial direction are thick (for example, the diameter d1), and the axial direction in which the first and second eccentric bodies 104A and 104B are formed. Even if the concave portion 102B is formed corresponding to the position, sufficient strength is ensured.

  On the hollow portion 102A side of the input shaft 102, a recess 102B is formed over the entire circumference corresponding to the axial position where the first and second eccentric bodies 104A and 104B are formed. The formation depth of the recess 102B is ΔD. That is, the inner diameter D2 of the input shaft 102 in the portion where the concave portion 102B is provided is larger than the inner diameter D1 of the input shaft 102 in the portion where the concave portion 102B is not provided by twice the depth ΔD (2 · ΔD). = D2-D1).

  The width Q1 from one end P1 to the other end P4 of the recess 102B is twice the width q from one end P5 to the other end P6 of the first and second eccentric bodies 104A and 104B. Wide enough to exceed. Even the width Q2 from one end P2 to the other end P3 of the bottom surface 102Bb (deepest part) of the recess 102B is wider than the width q of the first and second eccentric bodies 104A and 104B. The axial position from one end P2 to the other end P3 of the bottom surface 102Bb of the recess 102B is from one end P5 to the other end P6 of the first and second eccentric bodies 104A and 104B. The axial position is completely included. That is, on the input shaft 102, the axial range Q2 in which the bottom surface 102Bb of the recess 102B is present (formed) includes the axial range q in which the first and second eccentric bodies 104A and 104B are formed. Yes.

  The first and second cut ridge lines 102B1 and 102B2 forming the recess 102B are inclined with respect to a plane perpendicular to the axis O of the input shaft 102. That is, the cutting angles α1 and α2 of the first and second cutting ridge lines 102B1 and 102B2 are set to an angle of less than 90 degrees with respect to the axis O of the input shaft 102. In this embodiment, the specific cut angles α1 and α2 of the first and second cut ridge lines 102B1 and 102B2 are both approximately 30 degrees (shallow cut angle of 45 degrees or less). In other words, the shape of the cross section including the axis O of the concave portion 102B is “an isosceles trapezoid with a gentle inclination” in this embodiment. However, the cutting angles α1 and α2 are not necessarily the same, and may be non-identical in consideration of the outer peripheral shape of the input shaft, for example. Similarly, the two cut ridge lines do not necessarily have to be inclined with respect to a plane perpendicular to the axis of the input shaft. For example, for the cut ridge line on one side, the axis of the input shaft It may be a right angle (90 degrees).

  Next, the operation of the speed reducer 100 will be described.

  When power from a flat motor or the like is transmitted to the input shaft 102, the first and second eccentric bodies 104A and 104B formed integrally with the input shaft 102 rotate eccentrically. The eccentric rotations of the first and second eccentric bodies 104A and 104B are transmitted to the first and second external gears 108 and 110 via the first and second eccentric body bearings 106A and 106B, respectively. The second external gears 108 and 110 start swinging with respect to the axis O. On the other hand, an inner pin 112 that is fixed together with the first flange 118 and the frame body 120 is inserted into the inner pin holes 108 </ b> A and 110 </ b> A of the first and second external gears 108 and 110. Therefore, the first and second external gears 108 and 110 are restricted from rotating and only swing. Further, since the number of external pins 116 (the number of internal teeth) of the internal gear 122 is set to be slightly larger than the number of teeth of the first and second external gears 108 and 110, the internal gear 122 is Each time the first and second external gears 108 and 110 swing once, they rotate by the difference in the number of teeth (relative rotation with respect to the first and second external gears 108 and 110). The rotation of the internal gear 122 is taken out via a second flange 124 that rotates integrally with the internal gear 122 and a bolt 126.

  In the present embodiment, when the second flange 124 is designed to be fixed, the rotation of the input shaft 102 is decelerated and output as the rotation of the first flange 118 (that is, the frame body 120).

  Here, the rotation of the input shaft 102 causes friction between the first and second eccentric bodies 104A and 104B, the first and second eccentric body bearings 106A and 106B, and the first and second external gears 108 and 110. Heat is generated. However, this heat is smoothly released to the hollow portion 102A side, coupled with the increase in the heat dissipation surface area due to the presence of the recess 102B.

  In particular, in this embodiment, formation (processing) of the recess 102B is extremely easy. That is, in order to form (process) the first cut ridge line 102B1 of the recess 102, for example, the inner diameter is increased along the axial direction from one end P1 of the recess 102B (a position corresponding to one end of the recess). By gradually increasing from D1 to D2 (for example, by gradually moving the cutting tool (not shown) radially outward of the input shaft 102 while moving it in the axial direction), the first cutting edge 102B1 (the other end of the recess 102B) In the case of cutting from the end P2 side, a second cut ridge line 102B2) can be formed (first cut ridge line forming step). Here, once the movement in the radial direction is stopped and moved only in the axial direction, the bottom surface 102Bb having a constant inner diameter D2 can be formed (recess bottom surface forming step). After that, if the increased inner diameter D2 is gradually decreased to return to the inner diameter D1 before the increase (if the cutting tool is moved back in the radial direction while moving in the axial direction again), the second cutting ridgeline 102B2 (from the end P2 side) In the case of cutting, a first cut ridge line 102B1) can be formed (second cut ridge line forming step). As a result, a larger heat radiation area (as much as an inclined ridgeline) can be formed and secured very easily.

  The recess 102B may be formed simultaneously with the formation of the hollow portion 102A, or only the recess 102B may be separately formed after the hollow portion 102A is formed.

  Further, since the first and second cut ridge lines 102B1 and 102B2 are inclined with respect to a plane perpendicular to the axis O of the input shaft 102, the bottom surface 102Bb of the recess 102B and the first and second cut ridge lines 102B1 and 102B2 are , Crossing at an “obtuse angle”, it is possible to avoid stress concentration in the vicinity of the end portions P2 and P3 of the bottom surface 102Bb.

  In the present embodiment, the eccentric body 104 is formed integrally with the input shaft 102, and as a result, the concave portion 102B is formed in the thickened portion. For example, in the case of a structure in which an eccentric body is incorporated into the input shaft using a key or spline, the strength of the mounting portion of the eccentric body of the input shaft is reduced due to the presence of the key or spline. A recess with a depth cannot be formed. On the other hand, in the present embodiment, since the concave portion 102B can be formed in the thickened portion corresponding to the eccentric body 104, the deep concave portion 102B can be formed without reducing the strength, and a large heat dissipation effect and weight reduction. The effect can be demonstrated. Further, since the recess 102B is deep, the speed reducer 100 itself can be made lighter, and the input shaft 102 is light, so that the track efficiency can be improved.

  Furthermore, in the present embodiment, the end portions P2 and P3 of the bottom surface (the deepest portion) 102Bb of the recess 102B completely set the axial positions of the end portions P5 and P6 of the first and second eccentric bodies 104A and 104B, respectively. Therefore, the heat generated in the vicinity of the first and second eccentric bodies 104A and 104B can be efficiently released to the concave portion 102B side.

  In the present invention, it is not prohibited to increase the radiated heat by actively arranging or applying a member having higher thermal conductivity in the recess 102B. Thereby, there are cases in which heat can be released more efficiently than a simple recess.

  As described above, in the present embodiment, the shape of the cross section including the axis of the recess 102B is an isosceles trapezoid, but the present invention is not limited to this. The cut angles of the cut ridge lines are not necessarily equal, and the value is not limited to 30 degrees. However, in order to realize high heat radiation efficiency, ease of processing, and reduction of stress concentration at the same time, the cut ridge lines of the recesses are preferably inclined at a cut angle of 45 degrees or less with respect to the axis. It is desirable to leave. Thereby, a recessed part with higher heat dissipation efficiency and less stress concentration can be formed more easily.

  In the present embodiment, the inward swing meshing planetary gear speed reducer in which the rigid external gear swings is targeted, but the present invention is not limited to this. For example, the present invention can be applied to a so-called “bending mesh planetary speed reducer” in which relative rotation with an internal gear is extracted by bending an external gear. In this case, the ellipsoid used to bend the external gear and the outer periphery of the ellipse can be regarded as the eccentric body of the present invention.

The principal part expanded sectional view of the reduction gear which concerns on an example of 1st Embodiment of this invention. Overall cross-sectional view

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Reducer 102 ... Input shaft 102A ... Hollow part 102B ... Recessed part 104A, 104B ... 1st, 2nd eccentric body 106A, 106B ... Bearing for 1st, 2nd eccentric body 108, 110 ... 1st, 2nd external tooth Gear 122 ... Internal gear 142 ... Bearing 102B1, 102B2 ... Recessed cut ridgeline 102Bb ... Recessed bottom face α1, α2 ... First and second cut angles of the recessed cut ridgeline

Claims (6)

An external gear provided on the input shaft, an eccentric body provided on the input shaft, an external gear provided on the radially outer side of the eccentric body, and an internal gear internally meshing with the external gear. A reduction gear that takes out the relative rotation between the gear and the internal gear as an output,
The input shaft has a hollow portion in the center in the radial direction,
The eccentric body is formed integrally with the input shaft;
On the hollow portion side of the input shaft, a concave portion is provided over the entire circumference at an axial position including the axial position where the eccentric body is formed,
A speed reducer characterized in that a cut ridge line of the recess is inclined with respect to a plane perpendicular to the axis of the input shaft. In claim 1,
The speed reducer, wherein a cut angle of a cut ridge line on both sides of the recess is set to an angle of 45 degrees or less with respect to the axis of the input shaft. In claim 1 or 2,
On the input shaft, the axial range in which the deepest portion of the recess is formed includes the axial range in which the eccentric body is formed. An input shaft having a hollow portion, an eccentric body provided on the input shaft, an external gear provided on the radially outer side of the eccentric body, and an internal gear internally meshing with the external gear In the method of manufacturing the input shaft of the speed reducer that takes out the relative rotation between the external gear and the internal gear as an output,
In forming the concave portion over the entire circumference at the hollow portion side of the input shaft and including the axial position where the eccentric body is formed, the inner diameter of the hollow portion of the input shaft is set to the A first reduction ridge line forming step of forming a first cut ridge line of the recess by gradually increasing along the axial direction from a position corresponding to an end portion on one side of the recess is provided. The manufacturing method of the input shaft. In claim 4, further:
After forming the first notch ridge line of the recess by the first notch ridge line forming step, the increase of the inner diameter along the axial direction is stopped and gradually decreased along the axial direction, whereby the second notch of the recess is formed. The manufacturing method of the input shaft of the reduction gear characterized by including the 2nd notch ridgeline formation process which forms a ridgeline. The concave bottom surface forming step for securing a portion having a constant inner diameter along the axial direction between the first cut ridge line forming step and the second cut ridge line forming step according to claim 5. To manufacture the input shaft of a reduction gear.

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