TW201348621A - Gear transmission device - Google Patents

Abstract

A gear transmission device is provided. The gear transmission device includes an inner gear and an outer gear engaged with the inner gear while relatively rotating eccentrically. A shaft including an eccentric body is engaged with one of the inner gear and the outer gear. A gear ring adjacent to the eccentric body is mounted on the shaft. A slot is formed on the peripheral surface of the shaft. The slot extends from a position disposed with the eccentric body to two axial ends of the shaft through an inner side of the gear ring.

Description

Gear transmission

The present application claims priority based on Japanese Patent Application No. 2012-079453, filed on March 30, 2012. The entire contents of this application are incorporated herein by reference. This specification discloses a technique relating to a gear transmission.

A gear transmission in which an external gear is eccentrically rotated while being engaged with an internal gear is known. In such a gear transmission, an external gear or an internal gear is eccentrically rotated using a shaft (crank shaft) having an eccentric body. In Japanese Laid-Open Patent Publication No. 2006-29393, there is disclosed a gear transmission in which an external gear meshes with an internal gear and eccentrically rotates. In the following description, Japanese Patent Laid-Open No. 2006-29393 is referred to as Patent Document 1. In the gear transmission of Patent Document 1, a through hole is formed in the external gear. An eccentric body is engaged with the through hole through the cylindrical roller bearing. In Patent Document 1, a hole is provided inside the crankshaft in order to supply a lubricant to the cylindrical roller bearing. The hole runs straight from the end of the crankshaft to the cylindrical roller bearing. Lubricant is supplied to the cylindrical roller bearing through the hole.

In the gear transmission of Patent Document 1, a gear ring (washer, inner race) is attached to the crankshaft in order to restrict the movement of the crankshaft in the axial direction. The gear ring is attached to the crankshaft at a position adjacent to the eccentric body. This gear ring prevents lubricant from intruding into the interior of the cylindrical roller bearing. Therefore, in the technique of Patent Document 1, a lubricant is supplied to the inside of the cylindrical roller bearing without being hindered by the gear ring, and a passage of the lubricant is provided inside the crankshaft. However, in the gear transmission of Patent Document 1, the rolling elements (cylindrical rollers) sometimes block the outlet of the passage of the lubricant. As a result, the gear transmission of Patent Document 1 may be in a situation where it is difficult to supply the lubricant to the inside of the cylindrical roller bearing. The present specification provides a gear transmission excellent in performance of supplying lubricant to the inside of a cylindrical roller bearing.

The gear transmission disclosed in the present specification includes an internal gear, an external gear, a shaft that eccentrically rotates the internal gear or the external gear, and a gear ring mounted on the shaft. The outer gear is eccentrically rotated while being engaged with the inner gear. The shaft has an eccentric body. The eccentric body is engaged with a through hole formed in one of the internal gear and the external gear, and the engaged gear (the internal gear or the external gear) is eccentrically rotated. The gear ring is coaxially mounted to the shaft at a position adjacent to the eccentric body. The gear ring can be, for example, an inner ring of a bearing that supports the shaft. In the gear transmission, a groove is formed in the outer circumferential surface of the shaft from the inner side of the gear ring toward the axial direction of the shaft from the position where the eccentric body is disposed. Further, in the present specification, the shaft and the eccentric body may be collectively referred to as a "crankshaft". In addition, in the following description, the type in which the external gear is eccentrically rotated will be described. However, the techniques disclosed in this specification can also be applied to the class in which the internal gear rotates eccentrically. Type gear transmission.

In the case of a gear transmission of the type in which the external gear is eccentrically rotated, the eccentric body is engaged with the external gear. Specifically, the eccentric body is engaged with the through hole formed in the external gear via the cylindrical roller bearing. In the case of the above-described gear transmission, the lubricant existing at the axial end portion of the shaft is not blocked by the gear ring, but is supplied to the eccentric body through the groove formed in the shaft (through the inner side of the gear ring). More specifically, the lubricant is supplied to the surface (axial end face) of the eccentric body through the inner side of the gear ring. The lubricant supplied to the surface of the eccentric body is moved to the outer peripheral side of the eccentric body, thereby being supplied to the inside of the cylindrical roller bearing. The rolling elements (cylindrical rollers) of the cylindrical roller bearing do not come into contact with the surface of the eccentric body. Therefore, in the above-described gear transmission, the outlet of the lubricant (the surface of the eccentric body) is not blocked by the rolling elements (cylindrical rollers). The above-described gear transmission can supply more lubricant than ever before to the inside of the cylindrical roller bearing.

2‧‧‧ Carrier

2a‧‧‧1st board

2b‧‧‧ Column

2c‧‧‧2nd board

2d, 4, 507‧‧‧ through holes

5‧‧‧Top cover

6, 106, 206, 306, 406, 506‧‧‧ axes

6a, 206a‧‧‧ Part 1

6b, 206b‧‧‧ Part 2

8, 8X, 8Y‧‧‧ eccentric body

10, 510‧‧‧ crankshaft

14‧‧‧Tapered roller bearings

14a‧‧‧ Inner Ring

14b‧‧‧Taper roller

14c‧‧‧Outer Ring

16‧‧‧Washers

18, 18X, 18Y‧‧‧ cylindrical roller bearings

20, 20X, 20Y‧‧‧ external gear

22‧‧‧ internal needle

24‧‧‧Internal gear

30, 230, 330, 430‧‧‧ longitudinal slots

30a, 130a, 230a, 330a, 430a‧‧‧1st longitudinal slot

30b, 130b, 230b, 330b, 430b‧‧‧2nd longitudinal slot

32, 36‧‧‧ axis

33‧‧‧ transverse slot

34‧‧‧ input gear

40‧‧‧ bearing

42‧‧‧Shell

44‧‧‧ oil seal

50, 52‧‧‧ arrows

100, 500‧‧‧ gear transmission

507a‧‧‧Central through hole

507b‧‧‧1st through hole

507c‧‧‧2nd through hole

507d‧‧‧3rd through hole

D1, D2, D11, D12, D21, D22‧‧ depth

R1, R2, R11, R12, R21, R22‧‧‧ spacing

Fig. 1 is a cross-sectional view showing the gear transmission of the first embodiment.

Fig. 2 is an enlarged cross-sectional view showing a portion surrounded by a broken line II of Fig. 1.

Fig. 3 is a front view of the shaft used in the gear transmission of the first embodiment (viewed in a direction orthogonal to the axis of the shaft).

Fig. 4 is a cross-sectional view taken along line IV-IV of Fig. 3.

Fig. 5 is a cross-sectional view taken along line V-V of Fig. 3.

Fig. 6 is a cross-sectional view showing the shaft of the second embodiment (a portion in which the first vertical grooves are formed).

Fig. 7 is a cross-sectional view showing the shaft of the second embodiment (a portion in which the second vertical grooves are formed).

Fig. 8 is a front elevational view showing a shaft used in the gear transmission of the third embodiment.

Fig. 9 is a cross-sectional view taken along line IX-IX of Fig. 8.

Fig. 10 is a cross-sectional view taken along line X-X of Fig. 8.

Fig. 11 is a front elevational view showing a shaft used in the gear transmission of the fourth embodiment.

Fig. 12 is a front elevational view showing a shaft used in the gear transmission of the fifth embodiment.

Figure 13 is a cross-sectional view showing the gear transmission of the sixth embodiment.

Fig. 14 is a front elevational view showing a shaft used in the gear transmission of the sixth embodiment.

Fig. 15 is a sectional view taken along line XV-XV of Fig. 14.

Hereinafter, several technical features of the embodiments disclosed in the present specification are described. In addition, the matters described below are individually technically useful.

(Feature 1) A plurality of eccentric bodies may be fitted to the shaft. In this case, a gap may be provided between the eccentric bodies in the axial direction of the shaft. Further, the groove formed in the shaft may be extended to the gap. With this configuration, the lubricant is also supplied to the gap between the eccentric body and the eccentric body. It becomes easier to supply the lubricant to the inside of the cylindrical roller bearing.

(Feature 2) The groove formed in the shaft may be continuous from one end of the axial direction of the shaft to another side. Thereby the lubricant is easily moved in the axial direction of the shaft.

(Feature 3) In the case where the groove is continuous from one end in the axial direction of the shaft to the other end, a gear spline may be coupled to the groove. In the gear transmission, the input gear is sometimes fixed to the shaft in order to rotate the shaft. In this case, the input gear is engaged with the output shaft of the motor. By coupling the input gear pin groove to the groove for supplying the lubricant, it is not necessary to perform machining for fixing the input gear only to the shaft. An example of the input gear is a spur gear.

(Feature 4) The groove formed in the shaft may also extend obliquely with respect to the axis of the shaft. The force acting on the lubricant in the groove is accompanied by the rotation of the shaft. A large amount of lubricant can be supplied to the inside of the cylindrical roller bearing.

(Feature 5) The groove formed in the shaft may also be spiral. Even in the case of a spiral groove, the force acting on the lubricant in the groove can be applied to the rotation of the shaft. In addition, the length of the groove in the axial direction of the shaft can be made long. Since a large amount of lubricant is stored in the tank, it is easy to supply the lubricant to the inside of the cylindrical roller bearing.

(Feature 6) The gear ring mounted on the shaft may be an inner ring of a bearing that rotatably supports the shaft. Depending on the type of bearing, there is a bearing that requires an inner ring. In this case, if the gear ring is used as the inner ring of the bearing, the number of parts constituting the gear transmission can be reduced.

[Example 1] (First embodiment)

The gear transmission 100 will be described with reference to Figs. 1 to 5 . In the following description, in the case where a plurality of the same type of parts are described as a feature common to the parts, the letters of the symbols may be omitted. gear drive The device 100 is a type of speed reducer in which the external gear 20 meshes with the internal gear 24 while eccentrically rotating. The gear transmission 100 uses a difference in the number of teeth between the external gear 20 and the internal gear 24 to increase the torque transmitted to the crankshaft 10 (decelerate the rotation) and output it from the carrier 2. In other words, the gear transmission 100 rotates the carrier 2 relative to the case 42 by the difference in the number of teeth of the external gear 20 and the internal gear 24. Hereinafter, the gear transmission 100 will be described in detail.

As shown in FIG. 1, the gear transmission 100 includes an internal gear 24, a carrier 2, a crankshaft 10, and two external gears 20X, 20Y. The internal gear 24 includes a housing 42 and a plurality of internal pins 22 disposed on the inner circumference of the housing 42. The carrier 2 is supported by the housing 42 coaxially with the internal gear 24 by a pair of bearings 40. A pair of bearings 40 are angular contact ball bearings. A pair of angular contact ball bearings 40 restrict the carrier 2 from moving axially and radially relative to the housing 42.

The carrier 2 includes a first plate 2a and a second plate 2c. A through hole 2d extending in the direction of the axis 36 is formed in the first plate 2a and the second plate 2c. The columnar portion 2b extends from the first plate 2a toward the second plate 2c, and the columnar portion 2b and the second plate 2c are fixed. The columnar portion 2b of the carrier 2 passes through the through hole 4 of the external gear 20. A gap is ensured between the inner wall of the through hole 4 and the columnar portion 2b. Further, the axis 36 is the axis of the carrier 2 and the internal gear 24. The carrier 2 supports the crankshaft 10 and the external gear 20.

The axis 32 of the crankshaft 10 is parallel to the axis 36. That is, the crankshaft 10 extends parallel to the axis 36 at a position offset from the axis 36. The crankshaft 10 includes a shaft 6 and two eccentric bodies 8X, 8Y. The eccentric body 8 is fitted to the shaft 6. Specifically, the shaft 6 is press-fitted into the hole in the center of the eccentric bodies 8X and 8Y to fix the eccentric body 8 to the shaft 6. In the direction of the axis 32, a gap is provided between the eccentric body 8X and the eccentric body 8Y. In addition, it can also be on the surface of the eccentric body 8 (in the direction of the axis 32) The end faces are formed with grooves extending in the radial direction (the direction orthogonal to the axis 32). In particular, it is preferable to form a groove extending in the radial direction on the surface on the side adjacent to the gear ring of both surfaces of the eccentric body 8. Details on the gear ring will be described below. The crankshaft 10 is supported by the carrier 2 by a pair of tapered roller bearings 14. A pair of tapered roller bearings 14 restrict the axial and radial movement of the crankshaft 10 relative to the carrier 2.

The tapered roller bearing 14 includes an inner ring 14a that is fitted to the shaft 6 (crankshaft 10), a tapered roller 14b, and an outer race 14c that is attached to the carrier 2. A gasket 16 is inserted between the inner ring 14a and the eccentric body 8. The washer 16 is in contact with the eccentric body 8. The inner ring 14a and the washer 16 are both annular and are coaxially mounted to the shaft 6. The washer 16 restricts the cylindrical roller bearing 18 from moving in the axial direction. In the direction of the axis 32, the cylindrical roller bearings 18X, 18Y are disposed between the two washers 16. One end of the cylindrical roller bearing 18X is in contact with the washer 16, the other end of the cylindrical roller bearing 18X is in contact with one end of the cylindrical roller bearing 18Y, and the other end of the cylindrical roller bearing 18Y is in contact with the washer 16. With this configuration, the cylindrical roller bearings 18X, 18Y can be restricted from moving in the axial direction.

The washer 16 is positioned by the inner ring 14a. Therefore, it can be said that the inner ring 14a is integrated with the washer 16, and the cylindrical roller bearing 18 is restricted from moving in the axial direction. That is, the inner ring 14a and the gasket 16 have functional integrity. Therefore, it can be said that not only the gasket 16 is adjacent to the eccentric body 8, but also the inner ring 14a is adjacent to the eccentric body 8. The inner ring 14a and the washer 16 are examples of a gear ring. Further, the inner ring 14a and the gasket 16 may be integrally formed. Further, a groove extending in the radial direction may be formed on the surface of the gear ring (washer 16) on the side of the eccentric body 8.

In the direction of the axis 32, the eccentric bodies 8X, 8Y are in the two inner rings 14a Engaged in the shaft 6 (crankshaft 10). The eccentric bodies 8X and 8Y are located in the through holes of the external gears 20X and 20Y. The cylindrical roller bearing 18 is interposed between the inner circumferential surface of the through hole of the external gear 20 and the outer circumferential surface of the eccentric body 8. The eccentric body 8 is engaged with the through hole of the external gear 20 via the cylindrical roller bearing 18 . The outer gear 20 is supported by the carrier 2 via the crankshaft 10. Further, the gear transmission 100 may be provided with a plurality of crankshafts 10. Specifically, the gear transmission 100 is provided with three crankshafts 10. One of the three crankshafts 10 is represented in FIG. Each of the crankshafts 10 is disposed at equal intervals around the axis 36.

On the outer peripheral surface of the shaft 6, a plurality of longitudinal grooves 30 are formed in the axial direction of the shaft 6 (in the direction of the axis 32). Further, two lateral grooves 33 are formed on the shaft 6 in the circumferential direction (see also FIG. 3). The longitudinal groove 30 passes through the inner side of the inner ring 14a. More specifically, the longitudinal groove 30 extends from the inner side of the inner ring 14a toward the axial end of the shaft 6 from the end on the inner ring 14a side of the eccentric body 8. Thereby, the lubricant can be supplied to the surface of the eccentric body 8 on the inner ring 14a side from the axial end portion of the shaft 6. Further, the longitudinal groove 30 passes through the inner side of the eccentric body 8. More specifically, the longitudinal groove 30 extends from the end portion of the eccentric body 8 on the inner ring 14a side through the inner side of the eccentric body 8 to the gap portion between the eccentric body 8X and the eccentric body 8Y. Thereby, the lubricant can be supplied to the gap between the eccentric body 8X and the eccentric body 8Y from the axial end portion of the shaft 6. In the following description, the portion in which the inner ring 14a and the eccentric body 8 are attached to the shaft 6 is referred to as a first portion 6a, and the vertical groove 30 formed in the first portion 6a is referred to as a first vertical groove 30a. See also Figure 3).

The input gear 34 is fixed to the shaft 6 (crankshaft 10). The input gear 34 is coupled to the longitudinal groove 30 formed in the shaft 6. In the axial direction of the shaft 6, the input gear 34 is fixed to the shaft 6 outside the pair of tapered roller bearings 14. In the following description, there is a portion in the shaft 6 in which the input gear 34 is mounted as a second portion. 6b, the vertical groove 30 formed in the second portion 6b is referred to as a second vertical groove 30b (see also FIG. 3).

An oil seal 44 is disposed between the first plate 2a and the casing 42. A cap 5 is fitted into the through hole 2d of the first plate 2a. The oil seal 44 and the top cover 5 prevent lubricant or the like inside the gear transmission 100 from leaking to the outside of the gear transmission 100.

The operation of the gear transmission 100 will be briefly described. When the torque of the motor (not shown) is transmitted to the input gear 34, the crankshaft 10 rotates. The eccentric body 8 is eccentrically rotated with respect to the axis 32 with the rotation of the crankshaft 10. The external gear 20 rotates eccentrically while meshing with the internal gear 24 in accordance with the eccentric rotation of the eccentric body 8. The number of teeth of the external gear 20 is different from the number of teeth of the internal gear 24 (the number of the internal needles 22). As described above, the external gear 20 is supported on the carrier 2, and the internal gear 24 is formed on the inner peripheral surface of the casing 42. Accordingly, when the external gear 20 rotates eccentrically, the carrier 2 rotates relative to the casing 42 in accordance with the difference in the number of teeth of the external gear 20 and the internal gear 24 .

The advantages of the gear transmission 100 will be described with reference to FIG. As described above, the longitudinal groove 30 is formed on the outer circumference of the shaft 6. Lubricant is supplied into the longitudinal groove 30 from the axial end of the shaft 6. As indicated by the arrow 50, the lubricant in the longitudinal groove 30 is supplied to the inside of the cylindrical roller bearing 18 through the gap between the washer 16 and the eccentric body 8. Further, as indicated by an arrow 52, the lubricant is supplied to the inside of the cylindrical roller bearing 18 through the gap between the eccentric bodies 8X and 8Y. Specifically, the lubricant in the longitudinal groove 30 is supplied to the inside of the cylindrical roller bearing 18 along the surface (the end surface in the direction of the axis 32) of the eccentric body 8. The rolling elements (cylindrical rollers) of the cylindrical roller bearing 18 are not in contact with the surface of the eccentric body 8. Therefore, in the gear transmission 100, the cylindrical roller can be eliminated. The rolling elements of the bearing 18 are hindered, and the inside of the cylindrical roller bearing 18 is supplied with a lubricant.

As described above, the gasket 16 is in contact with the eccentric body 8. When the gasket 16 is in close contact with the eccentric body 8, the passage of the lubricant (the gap between the gasket 16 and the eccentric body 8) is narrowed. As a result, the lubricant may become difficult to move as indicated by the arrow 50. In this case, the surface of the gasket 16 on the side of the eccentric body 8 and/or the surface of the eccentric body 8 on the side of the gasket 16 may be formed in a groove extending in the radial direction. A gap is ensured between the gasket 16 and the eccentric body 8, and it becomes easy to supply the lubricant to the inside of the cylindrical roller bearing 18.

The features of the vertical grooves 30 formed in the shaft 6 will be described with reference to Figs. 3 to 5 . Moreover, FIG. 3 is a schematic representation of the features of the longitudinal grooves 30 formed in the shaft 6, and does not accurately indicate the number, spacing, and the like of the longitudinal grooves 30. As shown in Fig. 3, the longitudinal groove 30 extends from one end of the first portion 6a to the other end in the axial direction of the shaft 6. The vertical groove 30 is divided into the first vertical groove 30a and the second vertical groove 30b by the lateral grooves 33. Although the following description is made, the first vertical groove 30a and the second vertical groove 30b are processed at one time, and are substantially the same groove. Therefore, it can be said that the longitudinal groove 30 continuously extends from one end of the shaft 6 to the other end (the entirety of the first portion 6a and the second portion 6b).

As shown in FIGS. 4 and 5, the depth of the first vertical groove 30a (the maximum depth of the first vertical groove 30a) D1 is equal to the depth D2 of the second vertical groove 30b. Further, the pitch (interval in the circumferential direction) R1 of the first vertical groove 30a is equal to the pitch R2 of the second vertical groove 30b. In other words, the shape of the first vertical groove 30a formed in the first portion 6a in which the inner ring 14a and the eccentric body 8 are fitted and the shape of the second vertical groove 30b in which the second portion 6b of the input gear 34 is coupled to the pin groove are formed. the same.

As described above, the first longitudinal groove 30a and the second longitudinal groove 30b in the shaft 6 Since the shape is the same, the first vertical groove 30a and the second vertical groove 30b can be processed at one time. For example, after forming one end from the axial direction of the shaft 6 to the longitudinal groove 30 at the other end, the lateral groove 33 is formed, thereby forming the first vertical groove 30a and the second longitudinal groove 30b. In the gear transmission 100, the input gear 34 can be bolted to the shaft 6 using a longitudinal groove 30 as a moving passage of the lubricant. In other words, the lubricant can be supplied to the inside of the cylindrical roller bearing 18 using the longitudinal groove 30 for coupling the input gear 34 to the shaft. A gear ring that restricts the movement of the input gear 34 in the direction of the axis 32 is attached to the lateral groove 33.

(Second embodiment)

The gear transmission of the second embodiment will be described with reference to Figs. 6 and 7 . The gear transmission of the present embodiment differs from the gear transmission 100 of the first embodiment only in the shape of the groove formed in the shaft (crankshaft). Figure 6 corresponds to the cross section of Figure 3 of the gear transmission 100. Figure 7 corresponds to the cross section of Figure 5 of the gear transmission 100.

As shown in FIGS. 6 and 7, the depth D11 of the first vertical groove 130a is deeper than the depth D12 of the second vertical groove 130b. That is, the depth D12 of the second vertical groove 130b is shallower than the depth D11 of the first vertical groove 130a. The pitch R11 of the first vertical grooves 130a is equal to the pitch R12 of the second vertical grooves 130b. The shape of the second vertical groove 130b is the same as the shape of the second vertical groove 130b of the shaft 6 in the first embodiment (see also FIG. 5). The shaft 106 allows a large amount of lubricant to pass through the first longitudinal groove 130a as compared with the shaft 6. Therefore, more lubricant can be supplied to the inside of the cylindrical roller bearing 18 (refer to FIG. 1). Further, as described above, the pitch R11 of the first vertical grooves 130a is equal to the pitch R12 of the second vertical grooves 130b. The shaft 106 can be formed by merely forming a pitch R11 from one end to the other end of the shaft 106. After (R12) and the groove of the depth D12, a depth of a portion of the groove in the axial direction (corresponding to the portion of the first portion 6a of FIG. 3) is deepened to a depth D11. Therefore, it can be said that the longitudinal groove 130 also extends continuously from one end of the shaft to the other end.

(Third embodiment)

A gear transmission of a third embodiment will be described with reference to Figs. 8 to 10 . The gear transmission of the present embodiment is also different in shape of the groove formed only in the shaft (crankshaft) from the gear transmission 100 of the first embodiment. In addition, FIG. 8 shows in a schematic manner the features of the longitudinal grooves 230 formed in the shaft 206.

As shown in Fig. 8, the number of the first vertical grooves 230a is smaller than the number of the second vertical grooves 230b. That is, in the first portion 206a and the second portion 206b, there is a large difference in the shape of the vertical grooves. As shown in FIGS. 9 and 10, the depth D21 of the first vertical groove 230a is equal to the depth D22 of the second vertical groove 230b. The pitch R21 of the first vertical grooves 230a is wider than the pitch R22 of the second vertical grooves 230b. In other words, the pitch R22 of the adjacent second vertical grooves 230b formed in the second portion 206b is narrower than the pitch R21 of the adjacent first vertical grooves 230a formed in the first portion 206a. Further, the shape of the second vertical groove 230b is equal to the shape of the second vertical groove 30b of the shaft 6 (see also FIG. 5).

The first vertical groove 230a corresponds to a form in which one of the convex portions between the adjacent second vertical grooves 230b is deleted one at a time. By using the shaft 206, a large amount of lubricant can be passed through the first longitudinal groove 230a as compared with the case of using the shaft 6. As a result, more lubricant can be supplied to the inside of the cylindrical roller bearing 18 (refer to FIG. 1). In addition, the shaft 206 can only form the convex portion between the longitudinal grooves 230 for the first portion 206a of the shaft 206 by forming the groove of the pitch R22 and the depth D21 (D22) from one end to the other end of the shaft 206. Form one by deleting one. Therefore, It is said that the longitudinal groove 230 also extends continuously from one end of the shaft to the other end.

(Fourth embodiment)

A gear transmission of a fourth embodiment will be described with reference to Fig. 11 . The gear transmission of the present embodiment differs from the gear transmission 100 of the first embodiment only in the shape of the longitudinal groove formed in the shaft (crankshaft). In addition, FIG. 11 is a schematic representation of the features of the longitudinal grooves 330 formed in the shaft 306, rather than accurately indicating the number, spacing, and the like of the longitudinal grooves 330.

As shown in FIG. 11, the first vertical groove 330a extends obliquely with respect to the axial direction. The second longitudinal groove 330b extends in the axial direction. In the case of the shaft 306, when the shaft 306 rotates, the force of the lubricant in the first vertical groove 330a acting in the first vertical groove 330a acts. As a result, the amount of the lubricant supplied to the cylindrical roller bearing 18 (refer to FIG. 1) can be increased, thereby further suppressing the deterioration of the cylindrical roller bearing 18. Further, the first vertical groove 330a can be formed using a technique of manufacturing a helical gear. Further, since the second vertical groove 330b extends in the axial direction, the input gear 34 can be fixed by the second vertical groove 330b (see Fig. 1).

(Fifth Embodiment)

A gear transmission of a fifth embodiment will be described with reference to Fig. 12 . The gear transmission of the present embodiment differs from the gear transmission 100 of the first embodiment only in the shape of the longitudinal groove formed in the shaft (crankshaft). In addition, FIG. 12 is a schematic representation of features of the longitudinal grooves 430 formed in the shaft 406, rather than accurately indicating the number, spacing, and the like of the longitudinal grooves 430.

As shown in FIG. 12, in the shaft 406, the first vertical groove 430a extends obliquely with respect to the axial direction, and the first vertical groove 430a has a spiral shape. In the case of the shaft 406, if the shaft 406 rotates, the lubricant in the first vertical groove 430a acts on the first vertical groove 430a. Further, the length of the first vertical groove 430a can be made longer than that of the first vertical groove 330a of the shaft 306 of the fourth embodiment. Therefore, a large amount of lubricant can be held in the first vertical groove 430a. Further, since the second vertical groove 430b extends in the axial direction, the input gear 34 can be fixed by the second vertical groove 430b (see Fig. 1).

(Sixth embodiment)

The gear transmission 500 will be described with reference to Figs. 13 to 15 . The gear transmission device 500 is a modification of the gear transmission device 100, and the same components as those of the gear transmission device 100 are denoted by the same reference numerals or the same reference numerals, and the description thereof will be omitted. Gear transmission 500 only has a different configuration of crankshaft 510 than crankshaft 10 of gear transmission 100. More precisely, the configuration of the shaft 506 is different from the shaft 6 of the gear transmission 100.

As shown in FIG. 13, a through hole 507 is formed inside the shaft 506. In more detail, the central through hole 507a continuously extends from one end of the shaft 506 to the other end along the axis of the shaft 506. The first through hole 507b, the second through hole 507c, and the third through hole 507d extend in the radial direction of the shaft 506 (a direction orthogonal to the axis 32). The through holes 507b to 507d are connected to the center through hole 507a and the first vertical groove 30a. The first through hole 507b and the third through hole 507d communicate with the first vertical groove 30a at a position where the gasket 16 is disposed between the eccentric body 8 and the inner ring 14a in the direction of the axis line 32. The second through hole 507c is in the direction of the axis 32, and is in the eccentric body 8X, 8Y The first longitudinal groove 30a is connected to each other.

As shown in FIGS. 14 and 15, the through holes 507b to 507d connect the center through hole 507a and all of the first vertical grooves 30a. That is, the number of the respective through holes 507b to 507d is equal to the number of the first vertical grooves 30a. Further, the shapes of the through holes 507b to 507d are all the same. By providing the through hole 507, not only the lubricant is supplied from the outer circumference of the shaft 506 to the inside of the cylindrical roller bearing 18, but also the inside of the cylindrical roller bearing 18 is supplied with lubricant from the inside of the shaft 506. That is, by using the shaft 506, deterioration of the cylindrical roller bearing 18 can be further suppressed.

Further, the through holes 507b to 507d may be connected to the central through hole 507a and a part of the first vertical grooves 30a. That is, the number of the respective through holes 507b to 507d may be smaller than the number of the first vertical grooves 30a. When the crankshaft 510 rotates, the cylindrical roller bearing 18 moves around the eccentric body 8. Therefore, even if the through holes 507b to 507d are connected only to a part of the first vertical grooves 30a, the lubricant passing through the through holes 507b to 507d is spread over all the rolling elements (cylindrical rollers) of the cylindrical roller bearing 18. Further, it is not necessary to form all of the through holes 507b to 507d on the shaft 506. For example, the first through hole 507b and the third through hole 507d may be formed in the shaft 506. Alternatively, only the second through hole 507c may be formed in the shaft 506.

In the above embodiment, an example in which the longitudinal groove is continuous from one end of the shaft to the other end is shown. In either case, the eccentric bodies are each pressed into the shaft having a longitudinal groove extending from one end to the other end. However, as long as the longitudinal groove passes through the inner side of the inner ring of the tapered roller bearing. In this case, the crankshaft may be a crankshaft integrally formed with an eccentric body and a shaft. In addition, the eccentric body can also be one. If the groove passes through the inner side of the inner ring of the tapered roller bearing, the lubricant present at the axial end of the shaft can be moved to the surface of the eccentric body, so that the lubricant can be supplied into the cylindrical roller bearing.

Further, even when a plurality of eccentric bodies are fitted to the shaft and grooves are formed inside the eccentric bodies, it is not necessary to make the grooves continuous from one end of the shaft to the other end. The lubricant can be supplied between the eccentric bodies as long as the grooves are extended to the gaps of the eccentric bodies.

Bearings that support the shaft (crankshaft) may also not be tapered roller bearings. For example, it can also be a cylindrical roller bearing. In this case, it is not necessary to fit the inner ring to the shaft, and it is only necessary to fit the cylindrical gear ring to the shaft.

In the above embodiment, the gear transmission in which the external gear is eccentrically rotated has been described. However, the techniques disclosed in this specification are also applicable to gear transmissions in which the internal gear rotates eccentrically. It is important that a groove is formed in the outer peripheral surface of the shaft to which the eccentric body is fixed.

The specific examples of the present invention have been described in detail above, but these are merely examples and are not intended to limit the scope of the claims. The technology described in the patent application scope includes various modifications and changes to the specific examples described above. The technical elements described in the present specification or the drawings exhibit technical usefulness either singly or in various combinations, and are not limited to the combinations described in the patent application scope at the time of filing. In addition, the techniques exemplified in the present specification or the drawings achieve a plurality of purposes at the same time, and achieving one of the objectives is technically useful in itself.

2‧‧‧ Carrier

2a‧‧‧1st board

2b‧‧‧ Column

2c‧‧‧2nd board

2d, 4‧‧‧through holes

5‧‧‧Top cover

6‧‧‧Axis

8X, 8Y‧‧‧ eccentric body

10‧‧‧ crankshaft

14‧‧‧Tapered roller bearings

14a‧‧‧ Inner Ring

14b‧‧‧Taper roller

14c‧‧‧Outer Ring

16‧‧‧Washers

18, 18X, 18Y‧‧‧ cylindrical roller bearings

20, 20X, 20Y‧‧‧ external gear

22‧‧‧ internal needle

24‧‧‧Internal gear

30‧‧‧Longitudinal slot

30a‧‧‧1st longitudinal slot

30b‧‧‧2nd longitudinal slot

32, 36‧‧‧ axis

33‧‧‧ transverse slot

34‧‧‧ input gear

40‧‧‧ bearing

42‧‧‧Shell

44‧‧‧ oil seal

100‧‧‧Gear transmission

Claims (10)

A gear transmission device includes: an internal gear; an external gear that is eccentrically rotated while being engaged with the internal gear; the shaft includes an eccentric body, and the eccentric body is engaged with one of the internal gear or the external gear a through hole formed thereon, and one of the gears is eccentrically rotated; and a gear ring coaxially mounted on the shaft and adjacent to the eccentric body; and the outer peripheral surface of the shaft is self-disposed with the eccentric body A groove is formed at both ends of the gear ring through the inner side of the gear ring toward the axial direction of the shaft. The gear transmission according to claim 1, wherein a plurality of the eccentric bodies are fitted to the shaft; a gap is provided between each of the eccentric bodies in an axial direction of the shaft; and the groove extends to the above gap. The gear transmission according to claim 1 or 2, wherein the groove extends from one end in the axial direction of the shaft to the other end. The gear transmission of claim 3, wherein the gear pin groove is coupled to the groove. The gear transmission according to claim 4, wherein the groove formed in a portion of the pin groove to which the gear is coupled is shallower than the groove formed in the other portion. The gear transmission according to claim 4, wherein a pitch ratio of the adjacent grooves formed in a portion of the pin groove to which the gear is coupled is formed The spacing of the adjacent grooves of some of his sections is narrow. The gear transmission of claim 1 or 2, wherein the groove extends obliquely with respect to an axis of the shaft. The gear transmission of claim 7, wherein the groove is spiral. The gear transmission according to claim 1 or 2, wherein a central through hole is formed along an axial direction of the shaft; and a through hole connecting the groove and the central through hole extends in a radial direction of the shaft . The gear transmission of claim 1 or 2, wherein the gear ring is an inner ring of a bearing that rotatably supports the shaft.