deceleration device

Abstract

A reduction gear is provided. The reduction gear (1) of an embodiment includes a housing (2), a gear carrier (3) rotatably supported to the housing (2), a plurality of crankshafts (13) rotatably supported to the gear carrier (3), and an external gear (15, 16) housed in the gear carrier (3) and rotatably supported to the crankshafts (13) and engaged with an internal tooth pin (5). The gear carrier (3) includes a central through-hole (7a, 8a) formed on a first rotation axis (A1), a plurality of crankshaft insertion holes (7b, 8b) into which the plurality of crankshafts (13) are respectively inserted, a linking recess (28) formed in an outer end surface (7d) of the gear carrier (3) in an axial direction to communicate the central through-hole (7a, 8a) with the crankshaft insertion holes (7b, 8b), and a sealing cover (30) installed to the linking recess (28) and blocking the linking recess (28).

Description

Technical Field

[0001] This invention relates to a speed reduction device. Background Technology

[0002] Previously, as a speed reduction device, there was a so-called eccentric oscillating type speed reduction device. Such a speed reduction device has: a cylindrical housing (outer cylinder) with an internal gear; a gear carrier rotatably supported on the housing; multiple crankshafts rotatably supported on the gear carrier; and an external gear (oscillating gear) housed in the gear carrier and rotatably supported on the multiple crankshafts.

[0003] The gear carrier has a storage space (enclosed space) for accommodating the external gear. Furthermore, multiple crankshaft central through holes (crankshaft mounting holes) are formed at equal intervals along the circumference on the same pitch circle centered on the axis of rotation. Each crankshaft is inserted into its crankshaft insertion hole and rotatably supported on the gear carrier. Moreover, a central through hole (through hole) is formed coaxially with the axis of rotation on the gear carrier. The crankshaft insertion hole, the central through hole, and the storage space are connected.

[0004] To improve the driving efficiency of such a reduction gear, lubricant is sealed in the housing space and crankshaft insertion hole. This improves the lubricity of the reduction gear and suppresses heat generation during operation.

[0005] To prevent lubricant leakage, a sealing cap is provided in the reduction gear to block the crankshaft insertion hole and the central through hole (for example, see Patent Document 1).

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2014-84951 Summary of the Invention

[0009] The problem the invention aims to solve

[0010] However, when the crankshaft insertion hole and central through hole are sealed with a sealing cap as described in the previous technology, the flow of lubricant within the gear carrier is hindered. As a result, the lubricant itself overheats, leading to a problem where the heat generated during the reduction gear's operation cannot be effectively suppressed.

[0011] The present invention provides a speed reduction device that can prevent lubricant leakage and effectively suppress heat generation during driving.

[0012] Solution for solving the problem

[0013] A speed reduction device according to one embodiment of the present invention comprises: a cylindrical housing having an internal gear; a gear carrier disposed radially inside the housing and rotatably supported thereon; a plurality of crankshafts rotatably supported on the same pitch circle centered on the rotation axis of the gear carrier and subjected to an external rotational force; and an external gear housed in the gear carrier and rotatably supported on the crankshafts, meshing with the internal gear. The gear carrier comprises: a central through hole formed on the rotation axis; a plurality of crankshaft insertion holes into which the plurality of crankshafts are respectively inserted; a connecting hole formed on an end face of the gear carrier in the direction of the rotation axis, such that the central through hole communicates with the crankshaft insertion holes; and a sealing cap installed in the connecting hole and sealing the connecting hole.

[0014] This configuration allows the central through-hole to connect with the crankshaft insertion hole via the connecting hole. Therefore, lubricant can flow smoothly between the central through-hole and the crankshaft insertion hole via the connecting hole. Consequently, the heat generated during the operation of the reduction gear can be effectively suppressed using the lubricant.

[0015] Furthermore, the connecting hole is sealed with a cap. This prevents the lubricant sealed in the central through hole and crankshaft insertion hole from leaking out.

[0016] In the above structure, the connecting hole is formed on the same axis as the rotation axis and is circular when viewed from the direction of the rotation axis. When the imaginary circle that is tangent to the plurality of crankshaft insertion holes on the inner side of the rotation axis is defined as the inscribed circle, the diameter of the connecting hole is larger than the diameter of the inscribed circle.

[0017] In the above structure, the sealing cap includes: a cylindrical portion that fits into the connecting hole; a bottom portion that blocks the end of the cylindrical portion near the end face of the gear carrier; and an elastic covering portion that covers the outer peripheral surface of the cylindrical portion and the outer surface of the bottom portion, and is elastic, wherein at least a portion of the outer surface of the bottom portion is exposed from the elastic covering portion.

[0018] In the above structure, the object component for fixing the gear carrier is in contact with the exposed portion of the outer surface of the bottom.

[0019] In the above structure, the object component for fixing the gear carrier comes into contact with the exposed portion of the outer surface of the bottom via a heat-conducting component.

[0020] The effects of the invention

[0021] The aforementioned speed reduction device can prevent lubricant leakage and effectively suppress heat generation during operation. Attached Figure Description

[0022] Figure 1 This is a cross-sectional view of the deceleration device in an embodiment of the present invention.

[0023] Figure 2 This is a plan view of the deceleration device in the embodiment of the present invention viewed from the substrate side.

[0024] Figure 3 This is an enlarged cross-sectional view of the sealing cap in an embodiment of the present invention.

[0025] Figure 4 This is an enlarged cross-sectional view of the connecting recess and the surrounding area of ​​the deceleration device in the first modified example of the embodiment of the present invention.

[0026] Figure 5 This is an enlarged cross-sectional view of the connecting recess and the surrounding area of ​​the deceleration device in the second modified example of the embodiment of the present invention.

[0027] Figure 6 This is an enlarged cross-sectional view of the sealing cover and the area around the sealing cover of the deceleration device in the third variation of the embodiment of the present invention.

[0028] Figure 7 This is an enlarged cross-sectional view of the sealing cover and the area around the sealing cover of the deceleration device in the fourth variation of the embodiment of the present invention.

[0029] Explanation of reference numerals in the attached figures

[0030] 1. Reduction gear; 2. Housing; 3. Gear carrier; 5. Internal gear pin; 7a. Through hole in the center of the base plate; 7b. Crankshaft insertion hole in the base plate; 7d. Outer end face; 8a. Through hole in the center of the end plate; 8b. Crankshaft insertion hole in the end plate; 13. Crankshaft; 15. First external gear; 16. Second external gear; 27a. Crankshaft minor diameter 27b, Crankshaft large diameter hole (crankshaft insertion hole); 28, Connecting recess (connecting hole); 30, Sealing cap; 31, Cap body; 32, Elastic covering part; 33, Cylindrical part; 33a, End; 33b, Outer circumferential surface; 34, Bottom; 34a, Outer surface; 101, Movable part (object component); A1, First axis of rotation (axis of rotation); Ci, Inscribed circle; Co, Circumscribed circle; Cp, Pitch circle; S, Storage space. Detailed Implementation

[0031] Next, embodiments of the present invention will be described with reference to the accompanying drawings.

[0032] <Speed ​​Reduction Device>

[0033] Figure 1 This is a cross-sectional view of the speed reduction device 1.

[0034] like Figure 1 As shown, the reduction gear 1, for example, reduces the rotational speed of an electric motor (not shown) and outputs a speed reduction. The reduction gear 1 is a so-called eccentric oscillating type reduction gear. The reduction gear 1 includes a cylindrical housing 2, a gear carrier 3 rotatably disposed radially inside the housing 2, and a reduction mechanism 4 connected to the gear carrier 3. The central axis of the housing 2 is aligned with the rotational axis of the gear carrier 3.

[0035] In the following description, these central axes and rotation axes are collectively referred to as the first rotation axis A1. The direction parallel to the first rotation axis A1 is called the axial direction. The direction of rotation of the gear carrier 3 is called the circumferential direction. The radial direction of the housing 2, which is orthogonal to the axial and circumferential directions, is simply referred to as the radial direction. In addition, sometimes the central side of the axial direction of the housing 2 is referred to as the inner side of the axial direction, and the side of the axial direction opposite to the inner side is referred to as the outer side of the axial direction.

[0036] <Shell>

[0037] The housing 2 is formed of ductile iron. For example, FCD450 is used as ductile iron. An outer flange 2a extending radially outward is integrally formed on the outer peripheral surface of the housing 2. A plurality of bolt holes 2b are formed in the outer flange 2a. The bolt holes 2b are arranged at equal intervals in the circumferential direction. A bolt (not shown) is inserted into the bolt hole 2b and fastened, for example, to the fixing part 100 of an industrial robot to fix the reduction gear 1.

[0038] Multiple pin grooves 2c are formed along the axial direction on the inner circumferential surface 2d of the housing 2. The multiple pin grooves 2c are arranged at equal intervals in the circumferential direction. An internal toothed pin 5 is embedded in each pin groove 2c. The internal toothed pin 5 functions as an internal tooth that meshes with the external gears 15 and 16 of the reduction mechanism 4, which will be described later.

[0039] On the inner circumferential surface 2d of the housing 2, main bearings 6 are respectively provided on both sides of the axial direction. The gear carrier 3 is rotatably supported on the housing 2 by means of the main bearings 6.

[0040] <Gear Carrier>

[0041] The gear carrier 3 has a circular plate-shaped base plate portion 7 and an end plate portion 8 arranged opposite each other in the axial direction, and three column portions 9 protruding from the base plate portion 7 toward the end plate portion 8.

[0042] Each column portion 9 is arranged at equal intervals in the circumferential direction. An end plate portion 8 is disposed on the top end 9a of the column portion 9. The end plate portion 8 is fixed to the column portion 9 by bolts 10. In this state, a storage space S with a certain width in the axial direction is formed between the inner end face 7c on the axially inner side of the base plate portion 7 and the inner end face 8c on the axially inner side of the end plate portion 8.

[0043] A pin 11 is provided on the column portion 9 at a position radially inward from the bolt 10. The pin 11 positions the end plate portion 8 relative to the base plate portion 7. The pin 11 engages with a pin hole 12 provided in the end plate portion 8.

[0044] The base plate portion 7, end plate portion 8, and pillar portion 9 are formed of ductile iron. For example, FCD450 is used as the ductile iron. The outer peripheral surfaces of the base plate portion 7 and the end plate portion 8 are rotatably supported on the housing 2 by corresponding main bearings 6. A sealing portion 25 is provided on the outer peripheral surface of the base plate portion 7 at a position axially outward of the main bearing 6. The sealing portion 25 seals the outer peripheral surface of the base plate portion 7 with the inner peripheral surface 2d of the housing 2.

[0045] Figure 2 This is a plan view of the deceleration device 1 viewed from the 7th side of the base plate.

[0046] like Figure 1 , Figure 2 As shown, central through holes 7a and 8a (substrate central through hole 7a, end plate central through hole 8a; an example of the central through hole in the claims) are formed at the radial center of the substrate portion 7 and the radial center of the end plate portion 8, respectively. The two central through holes 7a and 8a are arranged coaxially. The two central through holes 7a and 8a are respectively connected to the storage space S.

[0047] On the base plate portion 7 and the end plate portion 8, three crankshaft insertion holes 7b and 8b (base plate crankshaft insertion hole 7b and end plate crankshaft insertion hole 8b) are formed between adjacent column portions 9 in the circumferential direction. The three base plate crankshaft insertion holes 7b formed on the base plate portion 7 side are arranged on the same pitch circle Cp centered on the first rotation axis A1. The three end plate crankshaft insertion holes 8b formed on the end plate portion 8 side are arranged on the same pitch circle Cp centered on the first rotation axis A1. In addition, each crankshaft insertion hole 7b and 8b is arranged coaxially. That is, the central axis A2 of the crankshaft insertion holes 7b and 8b that are opposite each other in the axial direction is parallel to the first rotation axis A1.

[0048] In the crankshaft insertion holes 7b on the substrate side of the substrate portion 7, an inner flange portion 26 is formed on the outer side in the axial direction. A small-diameter crankshaft hole 27a is formed on the inner circumferential surface of the inner flange portion 26. That is, the substrate crankshaft insertion hole 7b has a small-diameter crankshaft hole 27a formed on the inner circumferential surface of the inner flange portion 26 and a large-diameter crankshaft hole 27b formed on the inner side in the axial direction of the small-diameter crankshaft hole 27a.

[0049] The crankshaft minor diameter bore 27a communicates with the crankshaft major diameter bore 27b. The crankshaft major diameter bore 27b is formed such that its inner diameter increases relative to the crankshaft minor diameter bore 27a by a stepped transition. The inner diameter of the crankshaft major diameter bore 27b is the same as the inner diameter of the end plate crankshaft insertion hole 8b. Crankshaft bearings 18 are respectively provided in the crankshaft major diameter bore 27b (base plate crankshaft insertion hole 7b) and the end plate crankshaft insertion hole 8b. The crankshaft bearings 18 are, for example, tapered roller bearings.

[0050] On the outer end face 7d on the outer side of the axially outer side of the base plate portion 7, a plurality of internal thread portions 29 are formed on the outer periphery. These internal thread portions 29 are used to fix the gear carrier 3, for example, to the movable part (an example of the object component in the claim) 101 of an industrial robot. Bolts (not shown) can be fastened to the internal thread portions 29.

[0051] On the outer end face 7d on the outer side of the substrate portion 7, a connecting recess (an example of the connecting hole in the claim) 28 is formed coaxially with the first rotation axis A1. The connecting recess 28 is formed into a circular shape when viewed from the axial direction.

[0052] Here, when the imaginary circle tangent to the three small-diameter crankshaft holes 27a (substrate crankshaft insertion holes 7b) on the outer side opposite to the first axis of rotation A1 is defined as the circumcircle Co, the diameter D1 of the connecting recess 28 is larger than the diameter D2 of the circumcircle Co. Therefore, the bottom surface 28a of the connecting recess 28 communicates with the central through hole 7a of the substrate and the three substrate crankshaft insertion holes 7b. In other words, the central through hole 7a of the substrate and the three substrate crankshaft insertion holes 7b are connected via the connecting recess 28.

[0053] A sealing cap 30 is embedded in the connecting recess 28. The connecting recess 28 is sealed by the sealing cap 30.

[0054] <Sealing cap>

[0055] Figure 3 This is an enlarged cross-sectional view of the sealing cap 30.

[0056] like Figure 1 , Figure 3 As shown, the sealing cap 30 has a bottom cylindrical cap body 31 and an elastic covering portion 32 that covers the cap body 31. The cap body 31 is integrally formed with a cylindrical portion 33 that fits into the inner peripheral surface 28b of the connecting recess 28 and a bottom 34 of the axially outer end 33a of the sealing cylindrical portion 33. The elastic covering portion 32 covers the outer peripheral surface 33b of the cylindrical portion 33 and the axially outer outer surface 34a of the bottom 34.

[0057] The elastic covering portion 32 is clamped in a compressed state between the outer peripheral surface of the cylindrical portion 33 and the inner peripheral surface 28b of the connecting recess 28. As a result, the sealing performance of the sealing cap 30 is improved.

[0058] The sealing cap 30 simply blocks the opening 28c on the axially outer side of the connecting recess 28 using its bottom 34. Therefore, even when the sealing cap 30 is embedded in the connecting recess 28, the passage P through the connecting recess 28 between the central through hole 7a of the substrate and the three substrate crankshaft insertion holes 7b can be ensured.

[0059] Since the connecting recess 28 and the first rotation axis A1 are formed coaxially, the length of the passage P between the central through hole 7a of the substrate and each substrate crankshaft insertion hole 7b, i.e., the surface distance between the central through hole 7a of the substrate and each substrate crankshaft insertion hole 7b, is the same. The size of the passage P between the central through hole 7a of the substrate and each substrate crankshaft insertion hole 7b is also the same.

[0060] <Speed ​​Reduction Mechanism>

[0061] The reduction mechanism 4 reduces the rotation of the electric motor (not shown) at a certain rate, causing the gear carrier 3 to rotate relative to the housing 2. The reduction mechanism 4 includes: three crankshafts 13 inserted into crankshaft insertion holes 7b and 8b; transmission spur gears (an example of the gears in the claims) 14 disposed at the axial ends of each crankshaft 13; and two external gears 15 and 16 (first external gear 15 and second external gear 16) housed in the housing space S between the base plate portion 7 and the end plate portion 8.

[0062] External teeth 17 are formed on the outer periphery of each of the three transmission spur gears 14. These external teeth 17 mesh simultaneously with, for example, the motor shaft of an electric motor (not shown). Thus, when the motor shaft rotates, the three transmission spur gears 14 rotate simultaneously.

[0063] The crankshaft 13 is rotatably supported on the gear carrier 3 (base plate portion 7 and end plate portion 8) by means of crankshaft bearings 18. The crankshaft 13 has a shaft body 13c that rotates about a central axis A2, and a first eccentric portion 13a and a second eccentric portion 13b formed at the axial center of the shaft body 13c. The two axially opposite portions of the shaft body 13c are rotatably supported on the gear carrier 3 (base plate portion 7 and end plate portion 8) by means of crankshaft bearings 18.

[0064] The crankshaft body 13c and the transmission spur gear 14 are arranged coaxially and integrated. That is, the crankshaft 13 and the transmission spur gear 14 rotate as a whole around the central axis A2. Hereinafter, the central axis A2 will be referred to as the second rotation axis A2 of the crankshaft 13.

[0065] The first eccentric portion 13a and the second eccentric portion 13b are eccentric relative to the second rotation axis A2. The first eccentric portion 13a and the second eccentric portion 13b are axially adjacent between the two crankshaft bearings 18. In other words, the first eccentric portion 13a and the second eccentric portion 13b are axially adjacent between the base plate portion 7 and the end plate portion 8. The first eccentric portion 13a and the second eccentric portion 13b are arranged with a 180° phase angle offset.

[0066] The inner circumferential surfaces of roller bearings 19 are fitted into each of the eccentric portions 13a and 13b. The roller bearings 19 are, for example, cylindrical roller bearings. The first external gear 15 and the second external gear 16 are rotatably supported on each crankshaft 13 by means of the roller bearings 19.

[0067] The first external gear 15 and the second external gear 16 are disposed in the space between the base plate portion 7 and the end plate portion 8. Through holes 15a and 16a are respectively formed in the first external gear 15 and the second external gear 16 for fitting into the outer peripheral surface of the roller bearing 19. Thus, when the first eccentric portion 13a and the second eccentric portion 13b oscillate and rotate due to the rotation of the crankshaft 13, the first external gear 15 and the second external gear 16 oscillate and rotate by means of the roller bearing 19.

[0068] Openings 15b and 16b are formed on the first external gear 15 and the second external gear 16, respectively, to avoid interference with the column portion 9. Central through holes 15c and 16c are formed at the radial center of the first external gear 15 and the second external gear 16. Each central through hole 15c and 16c communicates with the storage space S.

[0069] External teeth 15d and 16d are formed on the outer periphery of the first external gear 15 and the outer periphery of the second external gear 16, respectively. The number of teeth of each external tooth 15d and 16d is, for example, one less than the number of internal tooth pins 5 of the housing 2.

[0070] <Operation of the speed reduction device>

[0071] Next, the operation of the deceleration device 1 will be explained.

[0072] First, before driving the reduction gear 1, a lubricant (not shown) is sealed inside the gear carrier 3. The lubricant is distributed evenly throughout the interior of the gear carrier 3.

[0073] In the reduction gear 1, when driven, for example, by an electric motor (not shown), three crankshafts 13 rotate simultaneously. Consequently, two external gears 15 and 16 oscillate and rotate. As these external gears 15 and 16 oscillate and rotate, portions of the external teeth 15d and 16d of each external gear 15 and 16 mesh with the internal tooth pins 5 of the housing 2.

[0074] The number of teeth on each of the external gears 15d and 16d is, for example, one less than the number of internal gear pins 5. Therefore, each of the external gears 15 and 16 rotates in a manner such that the meshing points of each of the external gears 15d and 16d with the internal gear pins 5 (housing 2) are staggered in the circumferential direction. This rotation is decelerated relative to the rotation of the crankshaft 13.

[0075] As the external gears 15 and 16 rotate, each crankshaft 13 also rotates around its own axis about the second rotation axis A2 and revolves around the first rotation axis A1. Each crankshaft 13 is rotatably supported on the gear carrier 3 (base plate 7 and end plate 8). Therefore, the gear carrier 3 rotates with the revolution of each crankshaft 13. As a result, the reduction gear 1 reduces the rotation of an electric motor (not shown) and outputs it. Thus, the movable part 101 is driven relative to the fixed part 100 of the industrial robot. However, the reduction gear 1 can also make the fixed part 100 movable relative to the movable part 101. That is, when the movable part 101 is fixed, the housing 2 rotates relative to the gear carrier 3, driving the fixed part 100 relative to the movable part 101.

[0076] Here, since lubricant is sealed inside the gear carrier 3, the driving resistance of the reduction gear 1 can be reduced as much as possible. Forces flowing out from the outer end face 7d of the base plate 7, which is the output side (opposite to the input side), easily act on the lubricant. However, a sealing cap 30 is embedded in the connecting recess 28 formed on the outer end face 7d of the base plate 7. Therefore, leakage of lubricant from the reduction gear 1 can be suppressed.

[0077] Furthermore, since the connecting recess 28 is connected to the central through hole 7a of the substrate and the crankshaft insertion hole 7b of the substrate, the leakage of lubricant from the central through hole 7a of the substrate and the crankshaft insertion hole 7b of the substrate can be suppressed simply by sealing the connecting recess 28.

[0078] The connecting recess 28 forms a passage P that communicates with the central through hole 7a of the substrate and the three crankshaft insertion holes 7b of the substrate. Lubricant flows through this passage P between the central through holes 7a, 8a and the crankshaft insertion holes 7b, 8b. Therefore, good lubricant flow can be achieved.

[0079] Thus, the gear carrier 3 includes central through holes 7a, 8a, crankshaft insertion holes 7b, 8b, connecting recesses 28 that connect these central through holes 7a, 8a to the crankshaft insertion holes 7b, 8b, and sealing caps 30 that seal the connecting recesses 28. Therefore, the central through holes 7a, 8a and the crankshaft insertion holes 7b, 8b can be connected via the connecting recesses 28. As a result, lubricant can flow smoothly between the central through holes 7a, 8a and the crankshaft insertion holes 7b, 8b via the connecting recesses 28. Therefore, the heat generated during the operation of the reduction gear 1 can be effectively suppressed using lubricant.

[0080] Furthermore, the connecting recess 28 is sealed by the sealing cap 30. Therefore, it is possible to prevent the lubricant sealed in each central through hole 7a, 8a and each crankshaft insertion hole 7b, 8b from leaking out.

[0081] The connecting recess 28 is formed coaxially with the first rotation axis A1 and is circular when viewed from the axial direction. The diameter D1 of the connecting recess 28 is larger than the diameter D2 of the circumscribed circle Co. Therefore, the central through hole 7a of the substrate can be connected to the crankshaft insertion holes 7b of each substrate. The length of the passage P between the central through hole 7a of the substrate and the crankshaft insertion holes 7b of each substrate, i.e., the surface distance between the central through hole 7a of the substrate and the crankshaft insertion holes 7b of each substrate, can be made the same. The size of the passage P between the central through hole 7a of the substrate and the crankshaft insertion holes 7b of each substrate can also be made the same. Therefore, the lubricant can flow smoothly and without leakage throughout the entire range of the gear carrier 3. Uneven flow of lubricant in the gear carrier 3 can also be suppressed. In addition, the heat generated during the operation of the reduction gear 1 can be suppressed more effectively.

[0082] [Example 1]

[0083] <Connecting Recess>

[0084] Next, quote Figure 2 ,based on Figure 4 The first modified example of the speed reduction device 1 will be described.

[0085] Figure 4 This is an enlarged cross-sectional view of the connecting recess 28 and the area surrounding the connecting recess 28 in the first modified example of the deceleration device 1. Figure 4 For ease of explanation, the state of the sealing cap 30 is shown with the cap removed.

[0086] In the above embodiment, the case where the diameter D1 of the connecting recess 28 is larger than the diameter D2 of the circumscribed circle Co has been described. However, it is not limited to this, as long as the diameter D1 of the connecting recess 28 at least meets the following requirements.

[0087] That is, such as Figure 2 , Figure 4 As shown, when the imaginary circle tangent to the three large-diameter crankshaft holes 27b (base plate crankshaft insertion holes 7b) on the inner side of the first rotation axis A1 is defined as the inscribed circle Ci, the diameter D1 of the connecting recess 28 only needs to be larger than the diameter D3 of the inscribed circle Ci. The sealing cover 30 only needs to be formed in accordance with the size of the connecting recess 28.

[0088] With this configuration, the central through holes 7a and 8a can be connected to the crankshaft insertion holes 7b and 8b via the connecting recess 28. Therefore, the same effect as the above-described embodiment can be achieved.

[0089] [Second variation]

[0090] <Connecting Recess>

[0091] Next, based on Figure 5 The second modification of the speed reduction device 1 will be described.

[0092] Figure 5 This is an enlarged cross-sectional view of the connecting recess 28 and the area around the connecting recess 28 of the deceleration device 1 in the second modified example. Figure 5 With the above Figure 4 Corresponding. In Figure 5 For ease of explanation, the state of the sealing cap 30 is shown with the cap removed.

[0093] In the above embodiment, the case where the connecting recess 28 and the first rotation axis A1 are formed coaxially has been described. The case where the connecting recess 28 is formed into a circular shape when viewed from the axial direction has also been described.

[0094] However, it is not limited to this, such as Figure 5 As shown, the connecting recess 28 only needs to connect the central through hole 7a of the substrate with the crankshaft insertion hole 7b of the substrate. The connecting recess 28 may not be coaxial with the first rotation axis A1. The shape of the connecting recess 28 may also not be circular when viewed from the axial direction. The sealing cap 30 only needs to be formed corresponding to the shape of the connecting recess 28. With this configuration, the same effect as the above-described embodiment can be achieved.

[0095] [3rd variation]

[0096] <Sealing cap>

[0097] Next, based on Figure 6 The third modification of the speed reduction device 1 will be described.

[0098] Figure 6 This is an enlarged cross-sectional view of the sealing cover 30 and the area around the sealing cover 30 of the deceleration device 1 in the third modification example.

[0099] In the above embodiment, the case where the elastic covering portion 32 of the sealing cover 30 of the deceleration device 1 covers the outer peripheral surface 33b of the cylindrical portion 33 of the main body 31 and the outer surface 34a of the bottom 34 is described.

[0100] However, it is not limited to this, such as Figure 6 As shown, the elastic covering portion 32 may not cover the outer surface 34a of the bottom 34. With this configuration, the outer surface 34a of the bottom 34 is exposed to the outside. For example, the movable part 101 of an industrial robot comes into contact with this outer surface 34a.

[0101] Therefore, according to the third modification described above, since the bottom 34 of the cover body 31 is exposed to the outside, the heat transferred to the cover body 31 via the lubricant (not shown) can be actively released from the bottom 34. Thus, the heat dissipation of the sealing cover 30 can be improved, and the heat generated during the operation of the deceleration device 1 can be more effectively suppressed.

[0102] Furthermore, the movable part 101 of the industrial robot comes into contact with the outer surface 34a of the bottom 34. Therefore, heat from the sealing cover 30 can be transferred to the movable part 101. Accordingly, the heat dissipation of the sealing cover 30 can be further improved.

[0103] In the third variation described above, the case where the bottom 34 of the cover body 31 is entirely exposed to the outside was explained. However, it is not limited to this, as long as at least a portion of the bottom 34 is exposed from the elastic covering portion 32. By partially exposing the bottom 34, the heat dissipation of the sealing cover 30 can be improved compared to the case where the bottom 34 is completely covered by the elastic covering portion 32.

[0104] [4th variation]

[0105] <Sealing cap>

[0106] Next, based on Figure 7 The fourth modification of the speed reduction device 1 will be described.

[0107] Figure 7 This is an enlarged cross-sectional view of the sealing cover 30 and the area around the sealing cover 30 of the deceleration device 1 in the fourth modification example. Figure 7 With the above Figure 6 correspond.

[0108] like Figure 7 As shown, the difference between the third and fourth modifications is that the bottom 34 of the third modification is in direct contact with the movable part 101, while the bottom 34 of the fourth modification is in contact with the movable part 101 via the heat-conducting member 50.

[0109] Examples of materials that can be used as heat-conducting components 50 include aluminum, copper, and thermal grease, which have high thermal conductivity. However, they are not limited to these, and various other components can be used as heat-conducting components 50.

[0110] Therefore, according to the fourth modification described above, in addition to having the same effect as the third modification described above, the heat from the sealing cover 30 can be transferred to the movable part 101 more efficiently via the heat-conducting member 50.

[0111] This invention is not limited to the above-described embodiments, but includes structures obtained by making various modifications to the above-described embodiments without departing from the spirit of this invention.

[0112] For example, in the above embodiment, the use of the speed reduction device 1 in an industrial robot has been described. However, it is not limited to this and the speed reduction device 1 can be used in various devices.

[0113] In the above embodiment, the case where the reduction gear 1 has three crankshafts 13 has been described. The case where each oscillating external gear 15 and 16 is oscillating and rotating using the three crankshafts 13 has been described. However, it is not limited to this. When the reduction gear 1 is configured, it is sufficient to have multiple crankshafts 13. It is sufficient as long as the number of crankshafts 13 is two or more and the gear carrier 3 has a structure with central through holes 7a and 8a.

[0114] The above-described embodiments and their variations can be appropriately combined.

[0115] In the embodiments disclosed in this specification, for a structure composed of multiple objects, the multiple objects can be integrated into one, or conversely, a structure composed of a single object can be divided into multiple objects. Whether or not they are integrated, as long as the configuration achieves the purpose of the invention, it is acceptable.

Claims

1. A speed reduction device, wherein, The speed reduction device has the following features: A cylindrical shell with internal gears; A gear carrier, which is disposed on the radially inner side of the housing and is rotatably supported on the housing; Multiple crankshafts, rotatably supported on the same pitch circle centered on the rotation axis of the gear carrier, receive external rotational force; as well as An external gear, housed in the gear carrier and rotatably supported on the crankshaft, meshes with the internal gear. The gear carrier includes: A central through hole is formed on the axis of rotation; Multiple crankshaft insertion holes, wherein the multiple crankshafts are respectively inserted into the multiple crankshaft insertion holes; A connecting hole, formed on the end face of the gear carrier in the direction of the rotation axis, connects the central through hole to the crankshaft insertion hole; and A sealing cap is installed in the connection hole and seals the connection hole.

2. The speed reduction device according to claim 1, wherein, The connecting hole is coaxial with the axis of rotation and is circular when viewed from the direction of the axis of rotation. When the imaginary circle tangent to the plurality of crankshaft insertion holes on the inner side, which is the axis of rotation, is defined as the inscribed circle, The diameter of the connecting hole is larger than the diameter of the inscribed circle.

3. The speed reduction device according to claim 1 or 2, wherein, The sealing cap has the following features: The cylindrical portion fits into the connecting hole; The bottom, which seals the end of the cylinder near the end face of the gear carrier; and An elastic covering portion covers the outer peripheral surface of the cylindrical portion and the outer surface of the bottom portion, and is elastic. At least a portion of the outer surface of the bottom is exposed from the elastic covering portion.

4. The speed reduction device according to claim 3, wherein, The object component for fixing the gear carrier comes into contact with the exposed portion of the outer surface of the bottom.

5. The speed reduction device according to claim 3, wherein, The object component for fixing the gear carrier comes into contact with the exposed portion of the outer surface of the bottom via a heat-conducting component.

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