Gear mechanism, reducer

Abstract

The present invention provides a gear mechanism and a speed reducer. The gear mechanism includes: a first shaft; a second shaft that forms an angle with the first shaft; a first gear set having a plurality of first gears that transmit the rotation of the first shaft to the second shaft; and a second gear set having a plurality of second gears that transmit the rotation of the second shaft transmitted from the first shaft to an output side, wherein a straight line connecting the rotation center of the first second gear closest to the second shaft and the rotation center of the last second gear closest to the output side of the plurality of second gears forms an angle with the first shaft when viewed along the second shaft.

Description

Technical Field

[0001] The invention relates to a gear mechanism and a speed reducer. Background Art

[0002] Industrial robots, machine tools, and the like use speed reducers to reduce the rotation speed of a rotational drive source such as a motor (see, for example, Patent Document 1).

[0003] Regarding the input gear of the speed reducer described in Patent Document 1, a meshing gear mechanism may be interposed between the input gear of the speed reducer and the output gear of the motor to transmit driving force.

[0004] When such a reducer with a gear mechanism is used to drive a rotary table, etc., it is desirable to reduce the thickness in the vertical direction, i.e., the direction along the axis of the reducer, so that it is flat. Therefore, a gear mechanism is known in which the axis of the motor and the axis of the reducer are arranged so as to intersect.

[0005] In this case, when viewed in the direction along the axis of the speed reducer, the running gear train of the gear mechanism and the motor shaft are arranged radially outward with the axis of the speed reducer as the center.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent No. 5231530 Summary of the Invention

[0009] Problems to be solved by the invention

[0010] However, for a rotary table, etc., it is preferable that the rotary drive source, such as the speed reducer and motor, be covered by the rotary table. In other words, it is preferable that the outermost portion of the motor, when viewed along the axis from the center of the rotary table, be smaller than the outer diameter of the table.

[0011] However, if the size of the reducer and motor is larger than the outer diameter of the table, the motor will protrude from the table mounting surface, which may hinder the miniaturization of the rotary table. As a result, the size of the reducer and motor required to achieve the predetermined output further limits the miniaturization of the table.

[0012] The present invention aims to achieve the following object: to provide a gear mechanism and a speed reducer capable of achieving both flattening and miniaturization of the area viewed along the axial direction.

[0013] Solutions for solving problems

[0014] A gear mechanism of one technical solution of the present invention comprises: a first shaft; a second shaft, which forms an angle with the first shaft; a first gear set, which has a plurality of first gears that transmit the rotation of the first shaft to the second shaft; and a second gear set, which has a plurality of second gears that transmit the rotation of the second shaft transmitted from the first shaft side to the output side, wherein a straight line connecting the rotation center of the first second gear closest to the second shaft side and the rotation center of the last second gear closest to the output side among the plurality of second gears forms an angle with the first shaft when viewed in the direction along the second shaft.

[0015] According to one aspect of the gear mechanism of the present invention, the direction from the rotation center of the first second gear toward the rotation center of the last second gear, as viewed along the second axis, intersects the direction of extension of the first axis. Consequently, the rotation center of the last second gear, as viewed along the second axis, is offset relative to the extension of the first axis. Consequently, the area required for the structure to transmit rotation from the first axis to the output side is reduced compared to a configuration in which the rotation center of the last second gear, as viewed along the second axis, is positioned at an extension of the first axis.

[0016] In the gear mechanism according to one aspect of the present invention, the angle formed by a straight line connecting the rotation center of the first second gear and the rotation center of the last second gear and the first axis may be a right angle when viewed in a direction along the second axis.

[0017] In a gear mechanism according to one aspect of the present invention, the first gear set may include a first bevel gear mounted on the first shaft and a second bevel gear meshing with the first bevel gear and mounted on the second shaft.

[0018] In the above structure, it may also be provided with: a first housing which accommodates the first gear set; a second housing which accommodates the second gear set, the second housing being mounted on the first housing; and an output housing which accommodates the output portion having a third shaft which becomes the output side, the output housing being mounted on the second housing at a position close to the first housing, and, at a position close to the first housing, the output housing has a cut surface in which the wall thickness of only the portion close to the first housing is reduced in the wall portion formed in the circumferential direction of the third shaft.

[0019] According to a technical solution of the gear mechanism of the present invention, the output part is arranged with the third shaft as the center, and the output part housing has a wall portion surrounding the radially outer side of the output part arranged around the third shaft. The wall portion of the output part is arranged on substantially the entire circumference of the third shaft. In addition, the wall thickness of the wall portion of the output part in the radial direction of the third shaft is substantially uniform in the circumferential direction of the third shaft, but the wall thickness is reduced only in the portion close to the first housing. Specifically, the wall portion of the output part is configured to be substantially cylindrical, and the portion opposite to the first housing is formed as a cut surface configured to be flat corresponding to the side surface of the first housing. As a result, the gap between the side surface of the first housing and the wall portion of the output part can be reduced, and thus, when viewed in the direction along the second axis, the distance from the third shaft to the side surface of the first housing can be reduced.

[0020] In the gear mechanism of one aspect of the present invention, the dimension of the first housing along the first axis as viewed along the second axis can be made smaller than the dimension of the output housing along the first axis as viewed along the second axis.

[0021] The gear mechanism of another technical solution of the present invention comprises: a first shaft; a second shaft, which forms an angle with the first shaft; a third shaft, which sets the same direction as the axial direction of the second shaft as the axial direction; a first gear set, which has a plurality of first gears that transmit the rotation of the first shaft to the second shaft; and a second gear set, which has a plurality of second gears that transmit the rotation of the second shaft to the third shaft, and a straight line connecting the rotation center of the first second gear closest to the second shaft side and the rotation center of the last second gear closest to the third shaft side among the plurality of second gears intersects the first shaft when viewed in the direction along the second shaft.

[0022] According to another aspect of the gear mechanism of the present invention, the direction from the rotation center of the first second gear toward the rotation center of the last second gear, as viewed along the second and third axes, intersects the direction of extension of the first axis. Consequently, the rotation center of the last second gear, as viewed along the second and third axes, is offset relative to the extension of the first axis. Consequently, compared to a configuration in which the rotation center of the last second gear, as viewed along the second and third axes, is positioned at an extension of the first axis, the area required for the configuration of the structure required to transmit rotation from the first axis to the third axis is reduced. Alternatively, the area required for the configuration of the structure required to transmit rotation from the third axis to the first axis is reduced.

[0023] In the above structure, it can also be provided with: the first shaft that inputs the rotational driving force; the output part, which has an output axis in a direction intersecting with the input axis of the first shaft and outputs the rotational driving force; the initial second gear, which has the second shaft along the direction of the output axis; and, when viewed along the direction of the output axis, the second shaft is arranged at a position extending the input axis, and the initial second gear transmits the rotational driving force from the first shaft using the first gear set; and the last second gear, which has the third shaft along the direction of the output axis, and, when viewed along the direction of the output axis, the third shaft is arranged at a position that becomes a direction from the rotation center of the initial second gear along a direction intersecting with the direction from the rotation center of the initial second gear toward the input axis, and the last second gear transmits the rotational driving force to the output part.

[0024] In the above structure, it can also be provided with: an output part, which has an output axis in a direction intersecting with the input axis of the first shaft, and is driven to output a rotational driving force; the initial second gear, which has the second shaft in the direction of the output axis, and the second shaft is arranged on a predetermined circumference centered on the position of the output axis when viewed along the direction of the output axis, the initial second gear transmits the rotational driving force from the first shaft using the first gear set, the first shaft is arranged in such a way that its axis becomes a tangent at the rotation center of the initial second gear on the circumference when viewed along the direction of the output axis; and the last second gear, which has the third shaft in the direction of the output axis, and the third shaft is arranged at a position closer to the output axis than the rotation center of the initial second gear when viewed along the direction of the output axis, and the last second gear transmits the rotational driving force to the output part.

[0025] In the above structure, the first gear set may be bevel gears meshing with each other.

[0026] Another technical solution of the reducer of the present invention comprises: a first shaft; a second shaft, which is at an angle to the first shaft; a first gear set, which has a plurality of first gears that transmit the rotation of the first shaft to the second shaft; a second gear set, which has a plurality of second gears that transmit the rotation of the second shaft transmitted from the first shaft side to the output side, and a straight line connecting the rotation center of the first second gear closest to the second shaft side and the rotation center of the last second gear closest to the output side among the plurality of second gears is at an angle to the first shaft when viewed in the direction along the second shaft; a rotational drive source, which drives the first shaft to rotate; and a reduction unit, which outputs the rotation of the last second gear as the output side.

[0027] According to another aspect of the reducer of the present invention, a straight line connecting the rotation center of the first second gear and the rotation center of the last second gear closest to the output side forms an angle with the first axis when viewed along the second axis. This reduces the distance from the rotation center of the last second gear to the point on the contour of the rotary drive source farthest from the rotation center. Consequently, the area required for installation of the reducer, as viewed along the second axis, is reduced.

[0028] Effects of the Invention

[0029] According to the technical solution of the present invention, it is possible to provide a gear mechanism and a speed reducer that can achieve both flattening and miniaturization of the area viewed along the axial direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a plan view showing a gear mechanism and a speed reducer according to an embodiment of the present invention.

[0031] Figure 2 It is along Figure 1 Cross-sectional view along line II-II.

[0032] Figure 3 It is along Figure 1 Cross-sectional view along line III-III.

[0033] Figure 4 It is a top view showing a conventional speed reducer.

[0034] Description of Reference Numerals

[0035] 1. Reducer; 2. Housing; 2a. Base (second housing); 2a1. First base; 2a2. Second base; 2b. First assembly (first housing); 2b1. First assembly side; 2b2. First assembly plate; 2c. Second assembly (output housing); 10. Motor (rotational drive source); 10a. Drive shaft; 11. Input shaft (first shaft); 11b. Drive-side gears (first bevel gear, first gear); 11c. Driven-side gears (second bevel gear, 1st gear); 20. Gear mechanism; 21. Lead-in gear (first second gear); 21a. Lead-in shaft (second shaft); 22. Center gear (last second gear); 22a. Center shaft (third shaft); 23. Idle gear (second gear); 23a. Idle shaft; 30. Speed ​​reduction unit (output unit); T0. Output axis; T1. Lead-in axis (second axis); T2. Center axis (third axis); T10. Drive axis, input axis (first axis); DETAILED DESCRIPTION

[0036] Hereinafter, embodiments of the gear mechanism and the speed reducer according to the present invention will be described with reference to the drawings.

[0037] Figure 1 1 is a plan view showing the gear mechanism and the speed reducer of this embodiment. Figure 2 It is along Figure 1 The cross-sectional view of line II-II, Figure 3 It is along Figure 1 The cross-sectional view of the III-III line in FIG. Figure 1 and Figure 2 In the figure, reference numeral 1 is a speed reducer.

[0038] like Figure 1 As shown, the speed reducer 1 of this embodiment transmits the rotational driving force of the motor (rotational driving source) 10 to the speed reduction unit (output unit) 30 via the gear mechanism 20 and outputs the rotational force around the output axis T0 of the speed reduction unit 30 at a predetermined speed reduction ratio.

[0039] In addition, the direction along the output axis T0 may be referred to as the up-down direction (vertical direction). The speed reducer 1 of the present embodiment can be applied to, for example, a table drive of a rotary table.

[0040] In reducer 1, as Figure 2 、 Figure 3 As shown, the gear mechanism 20 and the reduction unit 30 are housed in the housing 2. The motor 10 is mounted on the outside of the housing 2. The motor 10 drives a drive shaft 10a along a drive axis (input axis) T10 extending in a substantially horizontal direction. An input shaft (first shaft) 11 having an input axis (first axis) coaxial with the drive shaft 10a is mounted on the drive shaft 10a. The input shaft 11 is rotatably supported by the housing 2. The gear mechanism 20 is linked to the input shaft 11. The reduction unit 30 outputs a rotational speed lower than the rotational speed input from the gear mechanism 20.

[0041] The motor 10 and the gear mechanism 20 are positioned adjacent to each other as viewed along the output axis T0. Similarly, the gear mechanism 20 and the reduction unit 30 are positioned adjacent to each other as viewed along the output axis T0. The vertical positions of the motor 10 and the reduction unit 30 along the output axis T0 substantially overlap. The vertical position of the gear mechanism 20 along the output axis T0 is substantially the same as the vertical position of the motor 10 and the reduction unit 30 along the output axis T0, but the gear mechanism 20 is positioned slightly below and adjacent to the motor 10 and the reduction unit 30.

[0042] The gear mechanism 20 includes a sun gear (the last second gear) 22, which rotates about the center axis (the third axis) T2; an idler gear (the second gear) 23, which meshes with the sun gear 22; and an introduction gear (the first second gear) 21, which meshes with the idler gear 23 and receives the driving force from the motor 10 via the input shaft 11. The sun gear 22, the idler gear 23, and the introduction gear 21 are all spur gears and are arranged along the same horizontal plane.

[0043] The idler axis T3 of the idler gear 23, the introduction axis (second axis) T1 of the introduction gear 21, and the center axis T2 of the sun gear 22 are all parallel to the output axis T0. The center axis T2 of the sun gear 22 coincides with the output axis T0.

[0044] The central gear 22 rotates around the central axis T2. The idler gear 23 rotates around the idler axis T3. The lead-in gear 21 rotates around the lead-in axis T1.

[0045] As viewed in the direction along the output axis T0, a straight line L1 connecting the output axis T0 of the speed reduction unit 30 and the introduction axis T1 of the introduction gear 21 intersects the drive axis T10 of the drive shaft 10a and the input shaft 11. In the present embodiment, as viewed in the direction along the output axis T0, a straight line L1 connecting the position of the output axis T0 and the position of the introduction axis T1 is perpendicular to the drive axis T10 of the drive shaft 10a and the input shaft 11.

[0046] Drive axis T10 of the drive shaft 10a and input shaft 11 is tangent to a circle R0 centered at the output axis T0 of the speed reduction unit 30, as viewed along the output axis T0. Circle R0, as viewed along the output axis T0, has a radius equal to the distance from the output axis T0 of the speed reduction unit 30 to the lead-in axis T1 of the lead-in gear 21. Drive axis T10 of the drive shaft 10a and input shaft 11 is tangent to circle R0 at the lead-in axis T1 of the lead-in gear 21, as viewed along the output axis T0.

[0047] Furthermore, as viewed in the direction along the output axis T0, a straight line L2 is orthogonal to the straight line L1. This straight line L2 passes through the position of the output axis T0 of the reduction unit 30 and is parallel to the drive axis T10 of the drive shaft 10a and the input shaft 11. This straight line L1 extends from the position of the output axis T0 of the reduction unit 30 toward the position of the introduction axis T1 of the introduction gear 21. In other words, as viewed in the direction along the output axis T0, the drive axis T10 of the drive shaft 10a and the input shaft 11 serves as a tangent to the circle R0, with the output axis T0 serving as the center of the circle R0. The drive axis T10 of the drive shaft 10a and the input shaft 11 are parallel to the straight line L2 passing through the position of the output axis T0 and are offset from the straight line L2.

[0048] The housing 2 includes a base portion (second housing) 2a, a first assembly (first housing) 2b, and a second assembly (output portion housing) 2c.

[0049] The base portion 2a is formed into a plate shape and is arranged along a horizontal plane perpendicular to the output axis T0. The base portion 2a is arranged along the lower surface of the speed reducer 1. As viewed from the direction along the output axis T0, the first assembly 2b accommodating the gear mechanism 20 and the cylindrical second assembly 2c accommodating the speed reduction unit 30 are arranged side by side on the upper surface of the base portion 2a.

[0050] The first assembly 2b and the second assembly 2c are respectively coupled to the upper surface of the base portion 2a in an aligned state. The first assembly 2b and the second assembly 2c protrude upward from the upper surface of the base portion 2a. The first assembly 2b and the base portion 2a are coupled to each other in a manner that allows the interior of the speed reducer 1 to be sealed.

[0051] The cylindrical second assembly 2c is positioned so that its central axis is aligned with the output axis T0. The second assembly 2c is positioned adjacent to the first assembly 2b. The upper end of the second assembly 2c is positioned along the upper surface of the reducer 1. The second assembly 2c is secured to the upper surface of the base 2a using bolts 2j or the like. The second assembly 2c and the base 2a are coupled together in a manner that hermetically seals the interior of the reducer 1.

[0052] The cylindrical second assembly 2c is arranged over substantially the entire circumference of the output axis T0 in the circumferential direction.

[0053] The wall portion of the output portion is arranged over substantially the entire circumference of the third axis. In addition, a cut surface 2c1 is formed in the second component 2c at a position facing the first component 2b.

[0054] The cut surface 2c1 is set as a vertical plane parallel to the output axis T0. In addition, the cut surface 2c1 is set as a vertical plane parallel to the straight line L2 when viewed in the direction along the output axis T0.

[0055] Specifically, the second component 2c is a cylinder having a substantially uniform wall thickness in the radial direction of the output axis T0 and circumferentially about the output axis T0. Only the portion proximal to the first component 2b is cut into a planar shape, forming a cut surface 2c1. Specifically, the second component 2c is a cylinder having a uniform wall thickness in the radial direction, and a planar cut surface 2c1 is formed on the portion opposing the first component 2b, corresponding to the opposing surface of the first component 2b.

[0056] like Figure 2 As shown, the smallest wall thickness dimension M2c1 at the cutting surface 2c1 of the second component 2c is smaller than the other wall thickness dimensions M2c.

[0057] The base portion 2a comprises a first, plate-shaped base portion 2a1 and a second, plate-shaped base portion 2a2 having a smaller profile than the first base portion 2a1. The first base portion 2a1 has a profile capable of mounting both the first assembly 2b and the second assembly 2c. The second base portion 2a2 has a profile opposing the first assembly 2b. As discussed later, the second base portion 2a2 is integrally embedded within the first base portion 2a1, with the region opposing the first assembly 2b being integrally formed. The first and second base portions 2a1, 2a2 are joined together to hermetically seal the internal space 28b of the speed reducer 1.

[0058] As will be discussed later, the first base portion 2a1 is formed to have a thickness greater than that of the second base portion 2a2 so that it can be embedded therein. The second base portion 2a2 is exposed on the lower surface of the speed reducer 1. The second base portion 2a2 is integrally bonded to the first base portion 2a1 at a position opposite the first assembly 2b in the vertical direction.

[0059] The first assembly 2b includes a first assembly side portion 2b1 integrally joined to the upper surface of the first base portion 2a1 and a first assembly plate 2b2 integrally joined to the upper surface of the first assembly side portion 2b1.

[0060] The first assembly side portion 2b1 protrudes upward from the upper surface of the plate-shaped first base portion 2a1. The first assembly plate 2b2 is coupled to the first assembly side portion 2b1 so that the interior of the first assembly side portion 2b1 is sealed. The first assembly plate 2b2 is arranged substantially parallel to the first base portion 2a1 and the second base portion 2a2. The first assembly plate 2b2 is arranged along the upper surface of the speed reducer 1.

[0061] The first assembly 2b has a distal end of an input shaft 11 that transmits the rotational driving force of the motor 10 to the gear mechanism 20. The input shaft 11 is oriented in the horizontal direction.

[0062] The motor 10 has a drive shaft 10a. The motor 10 is fixed to the side of the first component side portion 2b1. The top end of the drive shaft 10a is set as the input shaft 11 that passes through the housing 2. A press-fit hole 11a for inserting the drive shaft 10a of the motor 10 is formed on the outer end surface of the input shaft 11. The motor 10 is fixed to the motor support member 26 mounted on the first component 2b. The drive shaft 10a of the motor 10 is set to extend in the horizontal direction (in the direction parallel to the base portion 2a) and is inserted into the press-fit hole 11a of the input shaft 11. The motor 10 is located slightly above the upper outer surface of the base portion 2a (on the first component 2b side).

[0063] A driving-side gear (first bevel gear, first gear) 11 b is attached to a distal end portion of the input shaft 11 .

[0064] The driving side gear 11b is a structure in which teeth are formed on the outer end of a disc-shaped portion protruding radially from the outer peripheral surface of the input shaft 11. The driven side gear (second bevel gear, first gear) 11c meshes with the driving side gear 11b. The driving side gear 11b and the driven side gear 11c are composed of bevel gears (bevel gears). In addition, the driving side gear 11b and the driven side gear 11c are not limited to bevel gears. The driving axis T10 of the driving side gear 11b and the introduction axis T1 of the introduction shaft 21a of the driven side gear 11c are in an intersecting positional relationship, and have a structure that can transmit driving force from the driving side gear 11b to the driven side gear 11c. The driven side gear 11c uses the introduction shaft 21a extending in the vertical direction as a rotation axis. The driven side gear 11c is arranged close to the second component 2c in the vertical direction of the introduction shaft 21a.

[0065] The introduction shaft 21a is composed of a linearly extending shaft member concentric with the rotation axis of the driven gear 11c. The introduction shaft 21a is supported by a bearing 21g (described later) with the introduction axis T1 perpendicular to the drive axis T10 of the input shaft 11. Specifically, the introduction shaft 21a is rotatably supported by the housing 2.

[0066] In the present embodiment, the drive axis T10 of the input shaft 11 is parallel to the upper surface of the speed reducer 1 , and the introduction axis T1 of the introduction shaft 21 a is perpendicular to the upper surface of the speed reducer 1 .

[0067] Furthermore, the positional relationship between the introduction axis T1 of the introduction shaft 21a and the drive axis T10 of the input shaft 11 is not limited to being orthogonal to each other, and may be arranged in a positional relationship other than parallel. For example, the drive axis T10 of the input shaft 11 may be tilted in the vertical direction such that the motor 10 side thereof is lowered relative to the horizontal position.

[0068] The driven gear 11c has teeth formed on the outer end of a disc-shaped portion that radially protrudes from the outer circumference of the guide shaft 21a. The outer end of the driven gear 11c fits within the expanded diameter portion 28d1 formed in the first assembly 2b. As will be discussed later, the expanded diameter portion 28d1 is located at the upper end of the internal space 28d formed in the first assembly side portion 2b1 and is sealed by the first assembly plate 2b2.

[0069] An internal space 28b is formed in the middle of the first base portion 2a1 in the vertical direction. The internal space 28b is formed along a horizontal plane perpendicular to the output axis T0.

[0070] The first base portion 2a1 has two through-holes 28a and 28d2 extending in the vertical direction. Both the through-holes 28a and 28d2 communicate with the internal space 28b.

[0071] The through hole 28a is arranged with the output axis T0 as the center line and is formed concentrically with the cylindrical second assembly 2c. The through hole 28a penetrates from the internal space 28b to the outside of the lower surface of the speed reducer 1.

[0072] The through hole 28d2 is formed at a position corresponding to the center of the introduction gear 21. The through hole 28d2 communicates from the internal space 28b to the internal space 28d of the first assembly 2b described later.

[0073] Internal space 28b houses the lead-in gear (the first second gear) 21, the idler gear (the second gear) 23, and the sun gear (the last second gear) 22 of the gear mechanism 20 in meshing engagement. Internal space 28b has a planar contour formed by the continuation of a portion concentric with the lead-in shaft 21a, a portion concentric with the idler shaft 23a, and a portion corresponding to the portion concentric with the sun gear 22.

[0074] Within internal space 28b, an introduction gear 21, serving as the gear mechanism 20, is coupled to the input shaft 11, which transmits the rotational drive force from the motor 10. An idler gear 23, meshing with the introduction gear 21 within internal space 28b, is rotatably held by the first base portion 2a1 and the second base portion 2a2. A central gear 22, located within internal space 28b, meshes with the idler gear 23 and transmits the rotation of the introduction gear 21.

[0075] The outer diameter of the sun gear 22 is larger than that of the introduction gear 21 and the number of teeth thereof is set to be greater than that of the introduction gear 21. Therefore, the rotation of the introduction gear 21 by the motor 10 is decelerated at a predetermined reduction ratio and transmitted to the sun gear 22 in this state.

[0076] The first base portion 2a1 has an opening 28b1 formed below the internal space 28b, opposite the introduction gear 21 and the idler gear 23. The second base portion 2a2 is inserted from below to close the opening 28b1. The second base portion 2a2 is fixed at a position midway in the vertical direction of the internal space 28b.

[0077] In the first base portion 2a1, an expanded diameter portion 28b2 is formed at the edge of the downward opening 28b1 of the internal space 28b, which is expanded in a stepped manner. A flange portion 2a2a formed in a manner extending toward the periphery of the second base portion 2a2 is embedded in the expanded diameter portion 28b2. In this state, the expanded diameter portion 28b2 and the flange portion 2a2a, whose surfaces are opposite to each other in the vertical direction, are in contact with each other. Thus, the position of the second base portion 2a2 relative to the first base portion 2a1 in the vertical direction is fixed. In addition, the expanded diameter portion 28b2 can also be formed to an end portion that becomes the contour of the first base portion 2a1 in the horizontal direction. A sealing member (sealed component) such as an O-ring can also be provided around the opening 28b1 at a position above the flange portion 2a2a.

[0078] The second base portion 2a2 has a support hole 21f and a support hole 23f that are circular in cross section and have a bottom and are formed separately on a surface located inside the internal space 28b.

[0079] A bearing 21g is mounted in the support hole 21f. The bearing 21g is mounted on the inner circumferential surface of the support hole 21f. The bearing 21g supports the lower end of the introduction shaft 21a. The introduction shaft 21a has an introduction axis T1 extending vertically along the output axis T0. The lower end of the introduction shaft 21a is inserted into the support hole 21f. The introduction gear 21 is mounted on the introduction shaft 21a so as to be close to the lower end of the introduction shaft 21a.

[0080] The support hole 23f rotatably supports the idler shaft 23a. The idler shaft 23a has an idler axis T3 extending vertically along the output axis T0. The lower end of the idler shaft 23a is inserted into the support hole 23f. An idler gear is connected to the idler shaft 23a.

[0081] An internal space 28d extending in the vertical direction is formed at a position of the first unit side portion 2b1 facing the support hole 21f. The internal space 28d extends in the vertical direction, and its lower end communicates with the internal space 28b via a through hole 28d2.

[0082] Internal space 28d is circular in cross section, corresponding to through-hole 28d2. The upper end of internal space 28d is blocked by first assembly plate 2b2. A bottomed, circular support hole 21h is formed on the lower surface of first assembly plate 2b2, within internal space 28d. A bearing 21g is mounted in support hole 21h. Bearing 21g is mounted on the inner circumferential surface of support hole 21h. Bearing 21g supports introduction shaft 21a. The upper end of introduction shaft 21a is inserted into support hole 21h.

[0083] In the first component 2b, an expanded diameter portion 28d1 is formed at the upper end of the internal space 28d. The driven side gear 11c is housed in the expanded diameter portion 28d1 below the bearing 21g. The lower end of the first component plate 2b2 is embedded in the upper end of the internal space 28d. A flange portion 2b2a is provided around the upper end of the first component plate 2b2, protruding radially outward. The flange portion 2b2a contacts the upper end of the first component side portion 2b1, thereby fixing the first component plate 2b2 in the vertical direction relative to the first component side portion 2b1. At the same time, the first component side portion 2b1 and the first component plate 2b2 are tightly fitted together, sealing the internal space 28d. A sealing member (sealing component) such as an O-ring can also be provided on the outer peripheral surface of the first component plate 2b2, below the flange portion 2b2a and inserted into the first component side portion 2b1.

[0084] A bearing 21g is mounted near the lower end of the interior space 28d in the first unit 2b to support the axial center of the guide shaft 21a. The bearing 21g is mounted on the inner peripheral surface of the first unit side portion 2b1 in the interior space 28d.

[0085] A downwardly projecting protrusion 2b4 is formed at the lower end of the first assembly side portion 2b1, which forms the lower end of the internal space 28d, around the through hole 28d2. The protrusion 2b4 is inserted into the through hole 28d2 and serves to position the first assembly side portion 2b1 and the first base portion 2a1.

[0086] A horizontally extending through-hole 28d4 is formed in the first assembly 2b at a position vertically corresponding to and below the expanded diameter portion 28d1 within the internal space 28d. The through-hole 28d4 extends toward the motor 10. The drive-side gear 11b is housed within the through-hole 28d4. An input shaft support 25 is formed outside the through-hole 28d4, surrounding the input shaft 11 and continuous with the first assembly side portion 2b1. The input shaft support 25 is cylindrical in shape, surrounding the input shaft 11, and has a bearing 24 disposed inside. The bearing 24 rotatably supports the input shaft 11. A motor support member 26 is secured outside the input shaft support 25. The interior of the input shaft support 25 has a diameter corresponding to that of the through-hole 28d4. The input shaft support 25 and the first assembly side portion 2b1 house the input shaft 11 and the drive-side gear 11b, sealing them from the outside.

[0087] An opening 28b3 is formed in the first base portion 2a1 on the upper side of the internal space 28b, facing the sun gear 22. Opening 28b3 is blocked by the second assembly 2c and the speed reduction unit 30. Opening 28b3 is formed into a planar contour centered on the output axis T0 and concentric with the second assembly 2c and the sun gear 22.

[0088] In the internal space 28b, the center gear 22 is rotatably supported on the cylinder 34. The cylinder 34 passes through the internal space 28b in the up-down direction. The cylinder 34 is arranged with the output axis T0 as the center. The cylinder 34 passes through the reducer 1 in the up-down direction. The lower end of the cylinder 34 is embedded in the through-hole 28a. A sealing member 34b may also be provided between the lower end of the cylinder 34 and the inner surface of the through-hole 28a. A flange portion 34a exposed to the upper surface of the reduction portion 30 is formed at the upper end of the cylinder 34. The flange portion 34a is formed so as to be recessed downward relative to the upper surface of the reducer 1. The cylinder 34 is arranged approximately at the center of the opening 28b3.

[0089] The center gear 22 is formed integrally with a gear 22d, which is coaxial with the center gear 22. The gear 22d has a smaller number of teeth than the center gear 22, and its diameter is set to be smaller than the diameter of the center gear 22. The center gear 22 and the gear 22d can rotate integrally around the cylinder 34. The gear 22d is arranged at a position above the center gear 22. Compared with the center gear 22, the gear 22d is arranged closer to the speed reduction unit 30. The gear 22d is set as the input side to the speed reduction unit 30. The gear 22d is housed inside the opening 28b3. The lower end of the center gear 22 is rotatably supported by the bearing 34c near the through hole 28a. The upper end of the center gear 22 is rotatably supported relative to the speed reduction unit 30 by the bearing 34c.

[0090] The speed reduction portion 30 is accommodated in the cylindrical second assembly 2 c fixed to the first base portion 2 a 1 .

[0091] The speed reduction unit 30 is preferably an eccentric oscillating speed reduction mechanism, for example, and includes a gear carrier 33 disposed inside the second assembly 2 c and a transmission shaft 31 that rotates as the sun gear 22 rotates.

[0092] The gear rack 33 is capable of rotating relative to the second component 2c with the output axis T0 as the center. Specifically, the relative rotation between the second component 2c and the gear rack 33 is achieved by a bearing 36 provided between the inner periphery of the second component 2c and the outer periphery of the gear rack 33. The gear rack 33 is exposed to the upper surface of the speed reduction portion 30. The gear rack 33 becomes the output side of the speed reduction portion 30. The lower end of the speed reduction portion 30 is opposite to the opening 28b3. The cylinder 34 passes through the central portion of the gear rack 33. The axis of the gear rack 33 is consistent with the output axis T0 which is the axis of the cylinder 34. The cylinder 34 can also be fixed to, for example, the gear rack 33.

[0093] The transmission shaft 31 is provided as the input side of the reduction gear 30, to which the rotational drive force is transmitted from the center gear 22. The transmission shaft 31 is mounted so as to be rotatable relative to the gear carrier 33 about an axis parallel to the output axis T0. Based on the rotation of the transmission shaft 31, the reduction gear 30 causes the second assembly 2c and the gear carrier 33 to rotate relative to each other at a speed slower than the rotation speed of the transmission shaft 31. A transmission gear 32 is provided on the transmission shaft 31, which meshes with the gear 22d. The transmission gear 32 is a spur gear.

[0094] The reducer 1 of this embodiment can also be fixed to a flat reducer mounting surface. In this state, a rotary table or the like can be placed on the upper surface of the gear frame 33. In this case, the rotary table is fixed to the upper surface of the gear frame 33 using fastening bolts.

[0095] In this speed reducer 1, when the motor 10 is driven, the drive shaft 10a rotates, rotating the input shaft 11, which is coaxial and integral with the drive shaft 10a. This drives the driven gear 11c, which meshes with the drive gear 11b attached to the input shaft 11, causing the introduction shaft 21a of the gear mechanism 20 to rotate about the introduction axis T1. Rotation of the introduction shaft 21a causes the introduction gear 21, which is coupled to the introduction shaft 21a, to rotate about the introduction axis T1. The rotation of the introduction gear 21 causes the idler gear 23, which meshes with the introduction gear 21, to rotate about the idler gear shaft 23a. Rotation of the idler gear 23 causes the sun gear 22, which meshes with the idler gear 23, to rotate about the output axis T0. Rotation of the sun gear 22 also causes the gear 22d, which is coaxial and integral with the sun gear 22, to rotate. This causes the transmission gear 32, which meshes with the gear 22d, to rotate, rotating the transmission shaft 31, which is integral with the transmission gear 32. Due to the rotation of the transmission shaft 31, the gear carrier 33 and the second assembly 2c serving as the outer cylinder of the speed reduction unit 30 rotate relatively at a speed slower than the rotation speed of the transmission shaft 31. As a result, the rotary table rotates.

[0096] In the reducer 1 of this embodiment, when viewed along the direction of the output axis T0, the straight line L1 is perpendicular to the drive axis T10, and the straight line L1 is perpendicular to the straight line L2. In addition, the straight line L2 is parallel to and offset from the drive axis T10. Therefore, in the reducer 1 of this embodiment, when viewed along the direction of the output axis T0, the distance from the position of the output axis T0, which is the center of the reducer 1, to the position on the outline of the motor 10 farthest from the position of the output axis T0 becomes Figure 1 The distance shown is RT.

[0097] Figure 4 It is a top view showing a conventional speed reducer.

[0098] Relative to Figure 1The reducer 1 of this embodiment shown in FIG. Figure 4 As shown, when viewed in the direction along the output axis T0, the straight line from the position of the output axis T0 of the speed reducer 30 to the position of the lead-in axis T1 of the lead-in gear 21 coincides with the drive axis T10 of the drive shaft 10a and the input shaft 11. In this case, the distance from the position of the output axis T0, which is the center position of the speed reducer 1, to the position on the outline of the motor 10 farthest from the position of the output axis T0 becomes Figure 4 The distance shown is RT0.

[0099] Among them, for Figure 4 The reducer shown in this configuration is similar to Figures 1 to 3 The reducer shown is different, but for Figures 1 to 3 The corresponding structures of the shown reducer are marked with the same reference numerals.

[0100] exist Figure 4 In the structure shown, the distance RT is shortened by an amount corresponding to the case where the distance RT0 is perpendicular to the straight line L1. When comparing them, it is obvious that the area required on the horizontal plane for arranging the speed reducer 1 can be reduced in this embodiment. Figure 4 In the conventional structure shown, the reducer cannot be arranged so that it is obscured by the rotary table unless the table has a diameter of RT0. In contrast, in this embodiment, even for a rotary table with a diameter of RT0 and a small planar profile, the reducer 1 can be arranged so that it is obscured by the table. Therefore, compared to a structure in which the drive shaft 10a passes through the output axis T0, the radial dimension of the reducer 1 can be reduced.

[0101] The gear mechanism of an embodiment of the present invention may have: an input shaft that inputs a rotational driving force; an output portion, which has an output axis in a direction intersecting with the input axis of the input shaft and outputs the rotational driving force; an introduction gear, which has an introduction axis along the direction of the output axis, and, when viewed along the direction of the output axis, is arranged at a position where the input axis is extended, and the input gear transmits the rotational driving force from the input shaft; and a center gear, which has a center axis along the direction of the output axis, and, when viewed along the direction of the output axis, is arranged at a position that is from the position of the introduction axis along a direction intersecting with the direction from the position of the introduction axis toward the input axis, and the center gear transmits the rotational driving force to the output portion.

[0102] With this structure, the direction from the lead-in axis toward the center axis, as viewed along the output axis, intersects the direction of extension of the input axis. Consequently, the position of the output axis, as viewed along the output axis, is offset relative to a position obtained by extending the input axis. Consequently, compared to a configuration where the output axis is positioned as an extension of the input axis, as viewed along the output axis, the area required for the structure to transmit the rotational drive force from the input side to the output portion is reduced. In other words, the area required to cover the distance from the output axis to the position farthest from the output axis, which forms the contour of the input-side rotational drive source, is reduced.

[0103] In the gear mechanism according to the embodiment of the present invention, the input shaft and the rotation shaft of the introduction gear can transmit driving force via the bevel gears that mesh with each other.

[0104] As a result, the dimension of the arrangement between the output portion and the rotational drive source serving as the input side can be shortened when viewed in the direction along the output axis, and the gear mechanism can be flattened.

[0105] The gear mechanism of an embodiment of the present invention may have: an input shaft that inputs a rotational driving force; an output portion, which has an output axis in a direction intersecting with the input axis of the input shaft and is driven to output the rotational driving force; an introduction gear, which has an introduction axis along the direction of the output axis, and, when viewed along the direction of the output axis, the introduction axis is arranged on a predetermined circumference centered on the position of the output axis, and the rotational driving force is transmitted from the input shaft, and the input shaft is arranged in such a way that its axis becomes a tangent to the position of the introduction axis on the circumference when viewed along the direction of the output axis; and a center gear, which has a center axis along the direction of the output axis, and, when viewed along the direction of the output axis, the center axis is arranged at a position closer to the output axis than the position of the introduction axis, and the center gear transmits the rotational driving force to the output portion.

[0106] In this manner, when viewed along the output axis, the input axis is arranged radially in a direction from the position of the lead-in axis toward the position of the center axis relative to the position of the output axis as the center of the circumference. Furthermore, when viewed along the output axis, the direction in which the input axis, a tangent to the circumference, extends is parallel to a straight line passing through the position of the output axis as the center of the circumference, and is offset from this straight line.

[0107] Thus, when viewed from the direction along the output axis, the direction in which the input axis extends intersects with the direction from the position of the introduction axis toward the position of the center axis.

[0108] Therefore, the arrangement area formed by the diameter of the circumference and the furthest position of the contour of the rotary drive source in the direction in which the input axis extends, as viewed in the direction along the output axis, can be reduced.

[0109] In addition, in this embodiment, the reducer 1 is mounted on a surface extending in the horizontal direction, and the reducer 1 is used to drive the rotary table, but the invention is not limited to this structure and use. The reducer 1 of this embodiment can also be fixed to a mounting surface extending in a direction other than the horizontal direction.

[0110] In addition, although the output side of the speed reduction unit 30 is described as the gear carrier 33, the present invention is not limited to this structure. Either the gear carrier 33 or the cylindrical second assembly 2c may be the output side.

[0111] Industrial applicability

[0112] The gear mechanism of the present invention is not limited to being applied to the speed reducer 1 of the above-mentioned embodiment, but can be applied to any machine or device.

Claims

1. A gear mechanism comprising: First axis; a second axis that is angled with respect to the first axis; a first gear set having a plurality of first gears for transmitting the rotation of the first shaft to the second shaft; a second gear set including a plurality of second gears for transmitting the rotation of the second shaft transmitted from the first shaft to an output side, wherein a straight line connecting a rotation center of an initial second gear closest to the second shaft and a rotation center of a final second gear closest to the output side of the plurality of second gears forms an angle with the first shaft when viewed in a direction along the second shaft; a first housing accommodating the first gear set; a second housing for accommodating the second gear set, the second housing being mounted on the first housing; as well as An output portion housing, which houses an output portion having a third axis on the output side, is mounted on the second housing at a position adjacent to the first housing, and has a cut surface at a position adjacent to the first housing, in which the wall thickness of only the portion opposite to the first housing is reduced, among the wall portions formed in the circumferential direction of the third axis.

2. The gear mechanism according to claim 1, wherein: The angle formed by a straight line connecting the rotation center of the first second gear and the rotation center of the last second gear and the first axis is a right angle when viewed in a direction along the second axis.

3. The gear mechanism according to claim 1 or 2, wherein: The first gear set includes a first bevel gear mounted on the first shaft and a second bevel gear meshing with the first bevel gear and mounted on the second shaft.

4. The gear mechanism according to claim 1, wherein: A dimension of the first housing in the direction along the first axis as viewed along the second axis is smaller than a dimension of the output portion housing in the direction along the first axis as viewed along the second axis.

5. A gear mechanism comprising: First axis; a second axis that is angled relative to the first axis; a third axis having an axial direction that is the same as the axial direction of the second axis; a first gear set having a plurality of first gears for transmitting the rotation of the first shaft to the second shaft; a second gear set including a plurality of second gears for transmitting the rotation of the second shaft to the third shaft, wherein a straight line connecting a rotation center of an initial second gear closest to the second shaft and a rotation center of a final second gear closest to the third shaft intersects the first shaft when viewed in a direction along the second shaft; a first housing accommodating the first gear set; a second housing for accommodating the second gear set, the second housing being mounted on the first housing; as well as An output portion housing, which houses the output portion having the third shaft on the output side, is mounted on the second housing at a position adjacent to the first housing, and has a cut surface at a position adjacent to the first housing, in which the wall thickness of only the portion opposite to the first housing is reduced, among the wall portions formed in the circumferential direction of the third shaft.

6. The gear mechanism according to claim 5, wherein: The gear mechanism has: the first shaft to which a rotational driving force is input; the output portion having an output axis in a direction intersecting the input axis of the first shaft and outputting a rotational driving force; The first second gear has the second shaft extending in the direction of the output axis; the second shaft is arranged at a position extending from the input axis when viewed in the direction of the output axis, and the first second gear receives rotational driving force from the first shaft by the first gear set; as well as The last second gear has the third shaft along the direction of the output axis, and, when viewed along the direction of the output axis, the third shaft is arranged at a position that is from the rotation center of the first second gear along a direction intersecting with the direction from the rotation center of the first second gear toward the input axis, and the last second gear transmits the rotational driving force to the output part.

7. The gear mechanism according to claim 5, wherein: The gear mechanism has: the first shaft to which a rotational driving force is input; the output portion having an output axis in a direction intersecting the input axis of the first shaft and being driven to output a rotational driving force; The first second gear has the second shaft extending in the direction along the output axis, and the second shaft is arranged on a predetermined circumference centered on the position of the output axis when viewed in the direction along the output axis, the first second gear receives rotational driving force from the first shaft by the first gear set, and the first shaft is arranged so that the axis thereof becomes a tangent to the rotation center of the first second gear on the circumference when viewed in the direction along the output axis; The last second gear has the third shaft along the direction of the output axis, and, when viewed along the direction of the output axis, the third shaft is arranged at a position closer to the output axis than the rotation center of the first second gear. The last second gear transmits the rotational driving force to the output part.

8. The gear mechanism according to claim 5, wherein: The first gear set is bevel gears that mesh with each other.

9. A reducer comprising: First axis; a second axis that is angled with respect to the first axis; a first gear set having a plurality of first gears for transmitting the rotation of the first shaft to the second shaft; a second gear set including a plurality of second gears for transmitting the rotation of the second shaft transmitted from the first shaft to an output side, wherein a straight line connecting a rotation center of an initial second gear closest to the second shaft and a rotation center of a final second gear closest to the output side of the plurality of second gears forms an angle with the first shaft when viewed in a direction along the second shaft; a rotation drive source that drives the first shaft to rotate; a speed reduction portion configured to output the rotation of the final second gear as the output side; a first housing accommodating the first gear set; a second housing for accommodating the second gear set, the second housing being mounted on the first housing; as well as An output portion housing, which houses an output portion having a third axis on the output side, is mounted on the second housing at a position adjacent to the first housing, and has a cut surface at a position adjacent to the first housing, in which the wall thickness of only the portion opposite to the first housing is reduced, among the wall portions formed in the circumferential direction of the third axis.

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