JP6762515B2 - Combined transmission - Google Patents

Description

The present invention relates to a composite transmission including a plurality of power transmission mechanisms.

A traction drive is used as a transmission that reduces or accelerates rotation driven by a drive source such as a motor. A traction drive is a type of friction transmission device that transmits power through an oil film formed between two surfaces having smooth surfaces. As an example, Patent Document 1 describes a transmission having a housing, an input shaft rotatably supported by the housing, and an output shaft rotatably supported on the coaxial line with the input shaft by the housing. (Micro traction drive) is disclosed.

In this transmission, the input shaft includes an inner ring, and the inner ring is formed with an angle groove as an inner ring raceway surface. An outer ring is fixed to the housing, and an angle groove is formed on the outer ring as an outer ring raceway surface. A plurality of rolling bodies (rotating bodies) are arranged between the inner ring raceway surface and the outer ring raceway surface. Further, a cage for holding each rolling element is provided integrally with the output shaft.

In this transmission, a rotational driving force is transmitted from the input shaft to the inner ring, and the rolling element revolves around the axis of the input shaft while rotating according to the rotational driving force of the inner ring. The rotational force due to the revolution of the rolling element is transmitted to the output shaft via the cage.

In the traction drive, it is necessary to apply a preload to the rolling elements so that the rolling elements roll according to the rotation of the inner ring. Therefore, a pressing ring capable of pressing the outer ring is arranged between the housing and the outer ring. This pressing ring has a plurality of inclined surfaces on the outer ring side. A pressing rotating body (pressing ball) is fitted between the pressing ring and the outer ring.

The transmission can adjust the preload on the rolling element by the outer ring raceway surface and the inner ring raceway surface by moving the outer ring to the input shaft side via the pressing rotating body by rotating the pressing ring. Yes (see paragraphs 0018 to 0022 and FIG. 1 of the same document).

Further, Patent Document 2 discloses a transmission (micro traction drive) capable of applying a preload to an inner ring raceway surface, an outer ring raceway surface and a rolling element by using a spring. In this transmission, an inner ring is provided on the tip side of the input shaft support bearing (angle bearing), and the inner ring and the inner ring of the input shaft support bearing are connected by a spring (second spring) and arranged coaxially with the inner ring. A part of the outer ring and the housing is connected by a spring (first spring). The inner ring and the outer ring are formed with an inner ring raceway surface and an outer ring raceway surface formed by an angle groove.

In this transmission, a normal force (preload) is applied to the contact surface between the rolling element (ball) and each raceway surface by the urging force of these springs (see paragraphs 0054 to 0066 and FIG. 4 of the same document). ).

Japanese Patent No. 3617645 Japanese Patent No. 3659925

As described above, since the conventional transmission uses a separate preload adjustment mechanism such as a pressing ring and a spring, the structure of the transmission is complicated, resulting in an increase in size and cost. Further, when preload is applied by using each raceway surface of the inner ring and the outer ring as an angle groove, slippage tends to occur in the rolling element, and there is a possibility that the rotational driving force cannot be reliably transmitted.

The present invention has been made in view of the above circumstances, and is a technique of simplifying the preload structure, downsizing the transmission, reliably transmitting the rotational driving force, and obtaining a large gear ratio. Make it a target issue.

The present invention is for solving the above-mentioned problems, and the input shaft, the output shaft for outputting the rotational driving force input to the input shaft, and the rotational driving force of the input shaft are set to a predetermined gear ratio. A preload is applied to the first transmission mechanism converted by, the second transmission mechanism that converts the rotational driving force transmitted from the first transmission mechanism at a predetermined gear ratio and transmits it to the output shaft, and the first transmission mechanism. A composite transmission including a preload mechanism to be applied, wherein the first transmission mechanism includes an inner ring provided on the input shaft and having a raceway surface, an outer ring having a raceway surface, and the raceway surface of the inner ring. The rotational driving force is transmitted to the second transmission mechanism by engaging with a plurality of rolling elements arranged so as to roll between the outer ring and the raceway surface and rotating the rolling elements. The second transmission mechanism includes an intermediate shaft, and the second transmission mechanism is associated with a solar member provided on the intermediate shaft, a planetary member that engages with the solar member, an annular member that engages with the planetary member, and the planetary member. The preload mechanism includes a carrier that transmits the rotational driving force to the output shaft by rotating together, and the preload mechanism makes contact with the diameter of the rolling element so that the rolling element comes into contact with the raceway surface of the inner ring. The rolling element is configured to be larger than the distance between the point and the contact point where the rolling element comes into contact with the raceway surface of the outer ring, and the input shaft, the intermediate shaft, the second transmission mechanism, and the above. an output shaft is characterized that you have arranged coaxially.

According to such a configuration, by setting the diameter of the rolling element to be larger than the distance between the above-mentioned contact points, when the rolling element is arranged between the inner ring and the outer ring, the inner ring, the outer ring, and the rolling element have axes. A stress in a direction orthogonal to the direction is generated, and this can be suitably applied as a preload. As a result, the rotational driving force input to the input shaft can be reliably transmitted to the output shaft via the first transmission mechanism and the second transmission mechanism. As described above, in the present invention, since the preload can be applied by using only the bearing structure composed of the inner ring, the outer ring and the rolling element without using a separate preload mechanism, the compound transmission is made smaller than the conventional one. it can. Further, in the present invention, a larger gear ratio can be obtained by using a second transmission mechanism including a planetary mechanism in addition to the first transmission mechanism.

In this case, the intermediate shaft has a power transmission unit that transmits the rotational driving force of the input shaft to the intermediate shaft by engaging with the rolling element and rotating, and the power transmission unit has the power transmission unit. It is desirable that the cage holds the rolling elements. According to this, the rolling elements are suitably held at predetermined intervals by the cage, and the cage rotates according to the rolling of the rolling elements, so that the rotational driving force can be reliably transmitted to the intermediate shaft.

In the composite transmission according to the present invention, the output shaft is provided between the output shaft and the second transmission mechanism, and the rotational driving force transmitted from the second transmission mechanism is converted at a predetermined gear ratio to output the output. A configuration may be adopted that further includes a third transmission mechanism that transmits to the shaft. By adding the third transmission mechanism in this way, an even larger gear ratio can be realized.

In this case, the third transmission mechanism is fixed to the carrier of the second transmission mechanism and has an inner ring having a raceway surface, an outer ring having a raceway surface, the raceway surface of the inner ring, and the raceway of the outer ring. Includes a plurality of rolling elements arranged so as to roll between the surfaces, and a power transmission unit that transmits the rotational driving force to the output shaft by engaging with the rolling elements and rotating. , the power transmission unit is retained vessel that holds the rolling elements, and it is desirable that the configured integrally with the output shaft. According to this, the rotary driving force can be reliably transmitted from the third transmission mechanism to the output shaft by rotating the cage in response to the rolling of the rolling element.

Further, in the composite transmission according to the present invention, the first transmission mechanism is provided between the first transmission mechanism and the second transmission mechanism, and the rotational driving force of the first transmission mechanism is converted at a predetermined gear ratio to obtain the above. the arrangement further comprises a third transmission mechanism you transmitted to the second transmission mechanism may be adopted. By adding the third transmission mechanism in this way, an even larger gear ratio can be realized.

In this case, the third transmission mechanism is an inner ring fixed to the intermediate shaft of the first transmission mechanism and having a raceway surface, an outer ring having a raceway surface, and the raceway surface of the inner ring and the outer ring of the outer ring. A plurality of rolling elements arranged to roll with the raceway surface and the rotational driving force of the first transmission mechanism are transferred to the second transmission mechanism by engaging with the rolling elements and rotating. It is desirable to include an intermediate shaft to transmit. According to this, the third transmission mechanism can reliably transmit the rotational driving force due to the rolling of the rolling element to the second transmission mechanism by the intermediate shaft thereof.

Further, the composite transmission according to the present invention includes a preload mechanism that applies preload to the third transmission mechanism, and the preload mechanism sets the diameter of the rolling element in the third transmission mechanism in the third transmission mechanism. It can be configured by setting the distance between the contact point where the rolling element comes into contact with the raceway surface of the inner ring and the contact point where the rolling element comes into contact with the raceway surface of the outer ring. According to this, by setting the diameter of the rolling element to be larger than the distance between the above-mentioned contact points, when the rolling element is arranged between the inner ring and the outer ring, the inner ring, the outer ring, and the rolling element have axes. A stress in a direction orthogonal to the direction is generated, and this can be suitably applied as a preload.

According to the present invention, the preload structure can be simplified, the transmission can be miniaturized, the rotational driving force can be reliably transmitted, and a large gear ratio can be obtained.

It is sectional drawing of the composite transmission which concerns on 1st Embodiment. It is a perspective view which includes the cross section of the main part of a compound transmission. It is a perspective view which shows the 1st transmission mechanism. It is an exploded perspective view which shows the 1st transmission mechanism. It is a figure which shows the inner ring, the outer ring and the rolling element in the 1st transmission mechanism. It is a perspective view which shows the 2nd transmission mechanism. It is an exploded perspective view which shows the 2nd transmission mechanism. It is a perspective view which shows the 3rd transmission mechanism. It is an exploded perspective view which shows the 3rd transmission mechanism. It is a figure which shows the inner ring, the outer ring and the rolling element in the 3rd transmission mechanism. It is sectional drawing of the compound transmission which concerns on 2nd Embodiment. It is sectional drawing of the composite transmission which concerns on 3rd Embodiment.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

1 to 10 show a first embodiment of the compound transmission according to the present invention. As shown in FIG. 1, the compound transmission 1 converts the input shaft 2, the output shaft 3 that outputs the rotational driving force input to the input shaft 2, and the rotational driving force of the input shaft 2 at a predetermined gear ratio. The first transmission mechanism 4 to be used, the second transmission mechanism 5 for converting the rotational driving force transmitted from the first transmission mechanism 4 at a predetermined gear ratio, and the rotational driving force transmitted from the second transmission mechanism 5 to be predetermined. It mainly includes a third transmission mechanism 6 that converts the gear ratio, and a casing 7 that houses the transmission mechanisms 4 to 6.

As shown in FIGS. 1 and 2, the input shaft 2 is supported by the casing 7 so that one end thereof is housed in the casing 7 and the other end thereof is exposed from the casing 7. One end of the input shaft 2 is a large diameter portion 2a, and the other end is a small diameter portion 2b. The large diameter portion 2a of the input shaft 2 is rotatably supported by the first transmission mechanism 4. At one end of the input shaft 2, a locking portion 2c is formed which has a larger diameter than the large diameter portion 2a and locks the input shaft 2 so as not to come off from the casing 7. Further, a protrusion 2d is formed at the center (axis center) of the end surface of the large diameter portion 2a in the axial direction. The protrusion 2d is formed in a hemispherical shape having a spherical surface. The small diameter portion 2b of the input shaft 2 is connected to a drive source (not shown) such as a motor.

As shown in FIGS. 1 and 2, the output shaft 3 is supported by the casing 7 so that one end thereof is housed in the casing 7 and the other end is exposed from the casing 7. The output shaft 3 has a large diameter portion 3a at one end and a small diameter portion 3b at the other end. The output shaft 3 is arranged coaxially with the input shaft 2 so that the large diameter portion 3a faces the large diameter portion 2a of the input shaft 2. The large diameter portion 3a of the output shaft 3 is supported by a bearing 8 held in the casing 7. A recess 3c with which a part of the second transmission mechanism 5 is engaged is formed at the center of the end surface of the large diameter portion 3a in the axial direction.

The first transmission mechanism 4 constitutes a traction drive with a bearing structure (for example, a deep groove ball bearing) that rotatably supports the input shaft 2. Specifically, as shown in FIGS. 1 to 4, the first transmission mechanism 4 includes an inner ring 9 fixed to the input shaft 2, an outer ring 10 coaxially arranged outside the inner ring 9, and an inner ring. A plurality of rolling elements 11 provided so as to roll between the 9 and the outer ring 10 and an intermediate shaft 13 including a cage 12 for holding the rolling elements 11 are provided.

The inner ring 9 is formed in an annular shape and is fitted and fixed to the large diameter portion 2a of the input shaft 2. The locking portion 2c of the input shaft 2 is in contact with the inner ring 9, and the locking portion 2c locks the input shaft 2 so that the input shaft 2 does not come off. The inner ring 9 has a concave raceway surface 9a on which the rolling element 11 can roll. The raceway surface 9a is formed in an arc shape in a cross-sectional view. Here, when the rolling element 11 is arranged between the inner ring 9 and the outer ring 10, a point on the raceway surface 9a of the inner ring 9 where the rolling element 11 can come into contact is set as a contact point CP1 (inner ring side contact point) (FIG. 5). The contact point CP1 is located at the deepest position of the concave raceway surface 9a, and is located on the center line X with respect to the raceway surface 9a.

The outer ring 10 is an annular body having an inner diameter larger than the outer diameter of the inner ring 9. The outer ring 10 is non-rotatably fixed inside the casing 7. The outer ring 10 has a concave raceway surface 10a on which the rolling element 11 can roll. The raceway surface 10a is formed in an arc shape in a cross-sectional view. Here, when the rolling element 11 is arranged between the inner ring 9 and the outer ring 10, the point on the raceway surface 10a where the rolling element 11 can come into contact is set as the contact point CP2 (outer ring side contact point) (see FIG. 5). .. The contact point CP2 is located at the deepest position of the concave raceway surface 10a, and is located on the center line X with respect to the raceway surface 10a.

In the present embodiment, the rolling element 11 is composed of balls (spheres), but is not limited to this, and may be composed of cylindrical rollers. As shown in FIG. 5, the diameter D1 of the rolling element 11 is the radial direction of the contact point CP1 on the raceway surface 9a of the inner ring 9 and the contact point CP2 on the raceway surface 10a of the outer ring 10 when the rolling element 11 is not incorporated. It is set to be larger than the distance L1 in. This distance L1 is the minimum radius of the inner ring 9 on the raceway surface 9a (the radius of the raceway surface 9a at the position of the contact point CP1) and the maximum radius of the outer ring 10 on the raceway surface 10a (the radius of the raceway surface 10a at the position of the contact point CP2). ) Corresponds to the difference. By setting the distance between the contact points CP1 and CP2 in this way, when the rolling element 11 is incorporated between the inner ring 9 and the outer ring 10, the bearing internal gap (radial gap) in the bearing structure becomes negative. A stress in a direction orthogonal to the axial direction can be generated in the inner ring 9, the outer ring 10, and the rolling element 11, and this can be applied as a preload. In this way, the preload mechanism 14 that applies preload to the first transmission mechanism 4 is configured depending on the relationship between the dimensions of the inner ring 9, the outer ring 10, and the rolling element 11.

The intermediate shaft 13 is located between the input shaft 2 and the output shaft 3 and is arranged coaxially with the intermediate shaft 13. The intermediate shaft 13 has a large diameter portion 13a at one end and a small diameter portion 13b at the other end. The large diameter portion 13a functions as a power transmission unit that engages with the rolling element 11 of the first transmission mechanism 4 and transmits the rotational driving force to the second transmission mechanism 5. The large diameter portion 13a integrally has a cage 12 for holding the rolling element 11. The cage 12 is formed with a notch 12a for holding the rolling element 11. Further, as shown in FIGS. 1 and 2, the large diameter portion 13a is supported by a bearing 15 held inside the casing 7.

The large diameter portion 13a has a recess 13c on its axial end surface to which the protrusion 2d of the input shaft 2 engages. The recess 13c is formed in the central portion (axial center portion) of the end surface of the large diameter portion 13a. As shown in FIG. 1, the protrusion 2d of the input shaft 2 is in contact (point contact) with the bottom surface of the recess 13c.

The small diameter portion 13b of the intermediate shaft 13 supports a part of the second transmission mechanism 5. A protrusion 13e is formed at the center (axis center) of the end face in the axial direction of the small diameter portion 13b. The protrusion 13e is formed in a hemispherical shape having a spherical surface.

The second transmission mechanism 5 includes a solar member 16 provided in the middle of the intermediate shaft 13 of the first transmission mechanism 4, a planetary member 17 that engages with the solar member 16, and an annular member 18 that engages with the planetary member 17. And a carrier 19 connected to the planetary member 17.

In the present embodiment, the sun member 16 is a sun gear, and the planet member 17 is three planetary gears that mesh with the sun gear 16. Further, the annular member 18 is an internal gear that meshes with the planetary gear 17. That is, the second transmission mechanism 5 in this embodiment is configured by a planetary gear mechanism. Hereinafter, the common code 16 is used for the sun member and the sun gear, and the common code 17 is used for the planet member and the planetary gear. Further, the common reference numeral 18 is used for the annular member and the internal gear.

The second transmission mechanism 5 is not limited to the planetary gear mechanism, and may be configured by, for example, a planetary roller mechanism (traction drive). In this case, the sun member 16, the planet member 17, and the annular member 18 are ring rollers to which the sun roller, the planet roller, and the planet roller are transposed, respectively.

As shown in FIGS. 1 and 2, the sun gear 16 is fixed to the small diameter portion 13b of the intermediate shaft 13. The planetary gear 17 is rotatably supported by an annular support member 20. The support member 20 is provided with a plurality of support shafts 21 capable of supporting the planetary gear 17. As shown in FIG. 1, the support shaft 21 rotatably supports the planetary gear 17 via the bearing 22. As shown in FIGS. 6 and 7, a total of six support shafts 21 are provided on the support member 20, three of which support shafts 21 support three planetary gears 17, and the remaining three. The support shaft 21 of the book does not support the planetary gear 17. However, the number of support shafts 21 varies depending on the design of the planetary gears 17 (or planetary rollers), and the number is not limited and may be any number.

The annular member (internal gear) 18 is non-rotatably fixed to the casing 7. As shown in FIGS. 6 and 7, the annular member (internal gear) 18 has a plurality of through holes 18a formed at intervals in the circumferential direction. The annular member (internal gear) 18 is fixed to the casing 7 via the through hole 18a, as will be described later.

The carrier 19 is located between the intermediate shaft 13 of the first transmission mechanism 4 and the output shaft 3, and is arranged coaxially with the intermediate shaft 13. The carrier 19 has a boss portion 19a and a flange portion 19b. The boss portion 19a is configured to support a part of the third transmission mechanism 6. A protrusion 19c is formed at one end of the boss portion 19a in the axial direction, and a recess 19d is formed at the other end.

The protrusion 19c is formed in a hemispherical shape having a spherical surface. The protrusion 19c is inserted into the recess 3c of the output shaft 3 and is in contact with the bottom surface thereof (point contact). The recess 19d is formed in the central portion (axial center portion) of the end surface at the other end of the boss portion 19a. A bearing 23 (slide bearing) is attached to the recess 19d. The bearing 23 supports the small diameter portion 13b of the intermediate shaft 13 in the first transmission mechanism 4. The protrusion 13e of the intermediate shaft 13 is in contact (point contact) with the bottom surface of the recess 19d. Further, the contact of the protrusion 19c may be supported by a general bearing.

As shown in FIGS. 1 and 7, the flange portion 19b of the carrier 19 has a plurality of through holes 19e formed at intervals in the circumferential direction thereof. The carrier 19 is connected to the planetary gear 17 by inserting the support shaft 21 into the through hole 19e.

The third transmission mechanism 6 constitutes a traction drive with a bearing structure (for example, a cylindrical roller bearing) that rotatably supports the carrier 19. As shown in FIGS. 1, 2, 8 and 9, the third transmission mechanism 6 is formed on the inner ring 24, the outer ring 25, the plurality of rolling elements 26, and the large diameter portion 3a of the output shaft 3. It is provided with a cage 27.

The inner ring 24 is formed in an annular shape and is fixed to the boss portion 19a of the carrier 19. The inner ring 24 has a raceway surface 24a on which the rolling element 26 can roll. The raceway surface 24a is formed to be linear in cross-sectional view. The raceway surface 24a has a contact point CP1 with which the rolling elements 26 can come into contact. The raceway surface 24a can make line contact with the rolling element 26, but the contact point CP1 is an arbitrary point at the line contact portion.

The outer ring 25 is formed in an annular shape and is fixed to the inside of the casing 7. The outer ring 25 has a raceway surface 25a on which the rolling element 26 can roll. The raceway surface 24a is formed to be linear in cross-sectional view. The raceway surface 25a has a contact point CP2 with which the rolling elements 26 can come into contact. The raceway surface 25a can make line contact with the rolling element 26, but the contact point CP2 is an arbitrary point at the line contact portion.

The rolling element 26 is composed of a cylindrical roller, but is not limited to this, and may be composed of a ball (sphere). As shown in FIG. 10, the diameter D2 of the rolling element 26 is a contact point CP1 on the raceway surface 24a of the inner ring 24 and a contact point CP2 on the raceway surface 25a of the outer ring 25 in a state where the rolling element 26 is not incorporated. It is set larger than the distance L2 in the radial direction. This distance L2 corresponds to the difference between the radius of the raceway surface 9a of the inner ring 9 and the radius of the raceway surface 10a of the outer ring 10.

As a result, when the rolling element 26 is incorporated between the inner ring 24 and the outer ring 25, the bearing internal gap in this bearing structure becomes negative. Therefore, when the rolling element 26 is incorporated between the inner ring 24 and the outer ring 25, stress in the direction orthogonal to the axial direction can be generated in the inner ring 24, the outer ring 25, and the rolling element 26, and this can be applied as a preload. In this way, the preload mechanism 28 that applies preload to the third transmission mechanism 6 is configured depending on the relationship between the dimensions of the inner ring 24, the outer ring 25, and the rolling element 26.

As shown in FIGS. 8 and 9, the cage 27 is integrally formed with the large diameter portion 3a of the output shaft 3. The cage 27 has a notch 27a that holds the rolling element 26. By engaging the rolling elements 26 with the notch 27a, the cage 27 holds the plurality of rolling elements 26 at equal intervals, and also applies the rotational driving force due to the rolling (rotation and revolution) of the rolling elements 26. It also functions as a power transmission unit that transmits to the output shaft 3.

As shown in FIG. 1, the casing 7 mainly includes a first component member 29 that supports the input shaft 2 and a second component member 30 that supports the output shaft 3.

As shown in FIG. 1, the first component member 29 has a boss portion 29a and a flange portion 29b. The boss portion 29a holds the outer ring 10 of the first transmission mechanism 4 and the bearing 15 that supports the intermediate shaft 13 on the inner diameter surface thereof. The flange portion 29b has a plurality of through holes 29c formed at equal intervals along the circumferential direction thereof.

As shown in FIG. 1, the second component 30 has a boss portion 30a and a flange portion 30b. An annular lid 31 is fixed to the end surface of the boss portion 30a. Further, the boss portion 30a holds the outer ring 25 in the third transmission mechanism 6 and the bearing 8 that supports the output shaft 3 on the inner diameter surface thereof. The flange portion 30b has screw holes 30c formed through the flange portion 30b at equal intervals along the circumferential direction thereof.

The first constituent member 29 and the second constituent member 30 are connected as follows. That is, the flange portions 29b and 30b are opposed to each other, and the annular member 18 is interposed between the flange portions 29b and 30b. At this time, the first through hole 29c of the flange portion 29b of the first constituent member 29, the through hole 18a of the annular member 18, and the screw hole 30c of the flange portion 30b of the second constituent member 30 are matched with each other. Further, a fixing member 32 such as a bolt is inserted into these holes 18a, 29c and 30c. By fastening the fixing member 32, the casing 7 is formed by integrally connecting the annular member 18 with the annular member 18 sandwiched between the first constituent member 29 and the second constituent member 30. In the present embodiment, the outer diameter surface of the annular member 18 is configured to be flush with the outer surface of each of the flange portions 29b and 30b, but the present invention is not limited to this, and for example, the flange portion 30b of the second component 30b. The annular member 18 may be fixed to the flange portion 30b while covering the entire outer diameter surface of the annular member 18.

Hereinafter, the operation mode of the composite transmission 1 (reducer) having the above configuration will be described.

When the input shaft 2 is rotated by the drive source, the inner ring 9 of the first transmission mechanism 4 rotates together with the input shaft 2. Then, the rolling element 11 in contact with the raceway surface 9a of the inner ring 9 revolves around the input shaft 2 (large diameter portion 2a) while rotating along with the rotation of the inner ring 9. When the rolling element 11 revolves in this way, the notch portion 12a of the cage 12 provided on the intermediate shaft 13 is driven by the rolling element 11. As the cage 12 rotates in response to the rolling of the rolling element 11, the intermediate shaft 13 rotates in the same direction as the input shaft 2 at a speed lower than the rotation speed of the input shaft 2 due to a constant reduction ratio.

When the intermediate shaft 13 rotates, the sun gear 16 fixed to the intermediate shaft 13 rotates accordingly. When the sun gear 16 rotates, the planetary gear 17 revolves around the sun gear 16 while rotating between the sun gear 16 and the internal gear 18. Due to the revolution of the planetary gear 17, the carrier 19 is driven by its support shaft 21. As a result, the carrier 19 rotates in the same direction as the input shaft 2 at a constant reduction ratio at a speed lower than the rotation speed of the intermediate shaft 13.

Further, the inner ring 24 of the third transmission mechanism 6 fixed to the carrier 19 rotates together with the carrier 19, and the rolling element 26 of the third transmission mechanism 6 revolves around the boss portion 19a of the carrier 19 while rotating accordingly. To do. The orbit of the rolling element 26 drives the cage 27 (large diameter portion 3a) of the output shaft 3. Due to the rotation of the cage 27, the output shaft 3 rotates in the same direction as the input shaft 2 at a constant reduction ratio at a speed lower than the rotation speed of the carrier 19.

According to the composite transmission 1 according to the present embodiment described above, the diameter D1 of the rolling element 11 in the first transmission mechanism 4 is set to be larger than the distance L1 between the contact points CP1 and CP2 in the inner ring 9 and the outer ring 10. The diameter D2 of the rolling element 26 in the third transmission mechanism 6 is set to be larger than the distance L2 between the contact points CP1 and CP2 in the inner ring 24 and the outer ring 25, and the rolling elements 11 and 26 are set to be larger than the inner rings 9 and 24, respectively. By disposing it between the outer rings 10 and 25, a suitable preload can be applied to the transmission mechanisms 4 and 6. Due to this preload, the rolling element 26 is less likely to slip.

Further, by applying a preload to the first transmission mechanism 4 and the third transmission mechanism 6 only by the bearing structure, the preload mechanisms 14 and 28 can be simplified to enable the compound transmission 1 without using a separate mechanism. Can be miniaturized. Further, since the compound transmission 1 is composed of a plurality of transmission mechanisms 4 to 6, a larger gear ratio (reduction ratio) can be realized.

FIG. 11 shows a second embodiment of the compound transmission according to the present invention. In the above first embodiment, the composite transmission 1 is configured by the first transmission mechanism 4 to the third transmission mechanism 6, but in the present embodiment, the third transmission mechanism 6 is omitted.

Similar to the first embodiment, the composite transmission 1 according to the present embodiment is a first transmission mechanism composed of an input shaft 2, an output shaft 3, an inner ring 9, an outer ring 10, a rolling element 11, and an intermediate shaft 13. A second transmission mechanism 5 composed of a sun gear 16, a planetary gear 17, an internal gear 18, and a carrier 19, a casing 7, and preload mechanisms 14 and 28 are provided.

The input shaft 2 has a large diameter portion 2a and a small diameter portion 2b as in the first embodiment, and is supported by the first constituent member 29 of the casing 7 via the first transmission mechanism 4. The output shaft 3 has a large diameter portion 3a and a small diameter portion 3b as in the first embodiment, but the first embodiment is different from the first embodiment in that the output shaft 3 has a bearing 33 in the recess 3c formed on the end surface of the large diameter portion 3a. different.

In the first embodiment, the protrusion 13e formed on the small diameter portion 13b of the intermediate shaft 13 is brought into contact with the bottom surface of the recess 19d of the carrier 19 in the second transmission mechanism 5, but in the present embodiment, the intermediate shaft 13 is contacted. The protrusion 13e is not formed. The small diameter portion 13b of the intermediate shaft 13 is supported by a bearing 33 provided in the recess 3c of the output shaft 3.

In the first embodiment, the through hole 29c is formed in the first constituent member 29 of the casing 7 and the screw hole 30c is formed in the second constituent member 30, but in the present embodiment, the first constituent member 29 is screwed. A hole 29c is formed, and a through hole 30c is formed in the second component 30.

In the first embodiment, the cage 27 holding the rolling element 26 of the third transmission mechanism 6 is integrally formed with the large diameter portion 3a of the output shaft 3, but in the present embodiment, the second transmission mechanism is formed. The carrier 19 in No. 5 is integrally formed with the large diameter portion 3a of the output shaft 3. That is, in the first embodiment, the rotational driving force of the second transmission mechanism 5 (carrier 19) is indirectly transmitted to the output shaft 3 via the third transmission mechanism 6, but in the present embodiment, the above Depending on the configuration, the rotational driving force of the second transmission mechanism 5 is directly transmitted to the output shaft 3.

The other configurations in the present embodiment are the same as those in the first embodiment, and the components common to the first embodiment are designated by a common reference numeral.

FIG. 12 shows a third embodiment of the compound transmission according to the present invention. The composite transmission 1 according to the present embodiment includes the first transmission mechanism 4 to the third transmission mechanism 6 as in the first embodiment, but the position of the third transmission mechanism 6 is the same as that of the first embodiment. different. In the first embodiment, the third transmission mechanism 6 is provided between the output shaft 3 and the second transmission mechanism 5, but in the present embodiment, the first transmission mechanism 4 and the second transmission mechanism 5 are used. It is provided in between.

Similar to the first embodiment, the first transmission mechanism 4 includes an inner ring 9, an outer ring 10, a rolling element 11, and an intermediate shaft (hereinafter referred to as “first intermediate shaft”) 13 including a cage 12. Preload is applied to the first transmission mechanism 4 by the preload mechanism 14. Further, the second transmission mechanism 4 includes a sun gear 16, a planetary member (planetary gear) 17, an annular member (internal gear) 18, and a carrier 19. The carrier 19 is integrated with the large diameter portion 3a of the output shaft 3 as in the second embodiment. A hole 19e is formed in the carrier 19, and the support shaft 21 of the second transmission mechanism 5 is engaged with the hole 19e.

The third transmission mechanism 6 includes an inner ring 24, an outer ring 25, and a rolling element 26, as in the first embodiment. Preload is applied to the third transmission mechanism 6 by the preload mechanism 28. The inner ring 24 is fixed to the large diameter portion 13a of the first intermediate shaft 13 in the first transmission mechanism 4. The outer ring 25 is fixed inside the first component 29 in the casing 7.

Further, the third transmission mechanism 6 includes an intermediate shaft (hereinafter, referred to as “second intermediate shaft”) 34 that engages with the rolling element 26. The second intermediate shaft 34 is located between the first intermediate shaft 13 and the output shaft 3 and is arranged coaxially with these. The second intermediate shaft 34 has a large diameter portion 34a at one end and a small diameter portion 34b at the other end. The large diameter portion 34a integrally has a cage 27 (power transmission portion) for holding the rolling element 26. The cage 27 is formed with a notch 27a for holding the rolling element 26. A recess 34c with which the protrusion 13e of the first intermediate shaft 13 engages is formed at the axial end of the large diameter portion 34a. The recess 34c is formed in the central portion (axial center portion) of the end surface of the large diameter portion 34a. The protrusion 13e of the first intermediate shaft 13 is in contact (point contact) with the bottom surface of the recess 34c.

The small diameter portion 34b of the second intermediate shaft 34 has a protrusion 34d at one end thereof. The protruding portion 34d is formed at a central portion (axial center portion) on the end surface of the small diameter portion 34b. The protrusion 34d is formed in a hemispherical shape having a spherical surface. The small diameter portion 34b is supported by a bearing 33 fitted in the recess 3c of the large diameter portion 3a of the output shaft 3. The protrusion 34d of the small diameter portion 34b is in contact (point contact) with the bottom surface of the recess 3c.

In the casing 7 of the present embodiment, in addition to the first component 29, the second component 30, and the lid 31, the tubular third component 35 arranged between the first component 29 and the internal gear 18 To be equipped with. The third component 35 holds the outer ring 25 of the third transmission mechanism 6 non-rotatably on its inner diameter surface. The third component 35 has a plurality of through holes 35a formed at intervals in the circumferential direction thereof. Each through hole 35a is configured to coincide with the through hole 29c of the first constituent member 29, the through hole 18a of the internal gear 18, and the screw hole 30c of the second constituent member 30. The third component 35 is connected to the first component 29 and the internal gear 18 via the through hole 35a and the fixing member 32.

The other configurations in the present embodiment are the same as those in the first embodiment, and the components common to the first embodiment are designated by a common reference numeral.

The present invention is not limited to the configuration of the above embodiment, nor is it limited to the above-mentioned action and effect. The present invention can be modified in various ways without departing from the gist of the present invention.

In the first embodiment described above, an example is shown in which the first transmission mechanism 4 has a bearing structure using deep groove ball bearings and the third transmission mechanism 6 has a bearing structure using cylindrical roller bearings, but the present invention is not limited to this. The first transmission mechanism 4 and the third transmission mechanism 6 may have the same type of bearing structure, or may be composed of bearings other than the bearings exemplified by the transmission mechanisms 4 and 6.

In the first and third embodiments described above, the compound transmission 1 including the three transmission mechanisms 4 to 6 has been illustrated, but the number of transmission mechanisms is not limited thereto. For example, a compound transmission 1 such as a fourth transmission mechanism having a planetary gear mechanism (or a planet roller mechanism) similar to the second transmission mechanism 5 and a fourth transmission mechanism having a bearing structure similar to the first transmission mechanism 4. May be configured by a further multi-stage transmission mechanism. Further, the third transmission mechanism 6 may be configured by a planetary mechanism.

That is, the composite transmission 1 according to the present invention has a transmission mechanism (first transmission mechanism 4) provided with a cage 12 for holding the rolling element 11 on the intermediate shaft 13, and a transmission mechanism including a planetary gear mechanism or a planet roller mechanism. It suffices to provide at least one (second transmission mechanism 5).

1 Combined transmission 2 Input shaft 3 Output shaft 4 1st transmission mechanism 5 2nd transmission mechanism 6 3rd transmission mechanism 9 Inner ring of 1st transmission mechanism 10 Outer ring of 1st transmission mechanism 11 Rolling element of 1st transmission mechanism 13 1st Intermediate shaft of transmission mechanism 14 Preload mechanism
16 Sun member 17 Planetary member 18 Circular member 24 Inner ring of the third transmission mechanism 25 Outer ring of the third transmission mechanism 26 Rolling body of the third transmission mechanism 28 Preload mechanism 34 Intermediate shaft of the third transmission mechanism (second intermediate shaft)

Claims (7)

Input axis and
An output shaft that outputs the rotational driving force input to the input shaft, and
A first transmission mechanism that converts the rotational driving force of the input shaft at a predetermined gear ratio, and
A second transmission mechanism that converts the rotational driving force transmitted from the first transmission mechanism at a predetermined gear ratio and transmits it to the output shaft.
A compound transmission including a preload mechanism that applies preload to the first transmission mechanism.
The first transmission mechanism is provided on the input shaft and rolls between an inner ring having a raceway surface, an outer ring having a raceway surface, and the raceway surface of the inner ring and the raceway surface of the outer ring. A plurality of rolling elements to be arranged and an intermediate shaft for transmitting the rotational driving force to the second transmission mechanism by engaging with the rolling elements and rotating are provided.
The second transmission mechanism rotates by engaging with a solar member provided on the intermediate shaft, a planetary member engaging with the solar member, an annular member engaging with the planetary member, and the planetary member. A carrier that transmits the rotational driving force to the output shaft is provided.
The preload mechanism makes the diameter of the rolling element larger than the distance between the contact point where the rolling element contacts the raceway surface of the inner ring and the contact point where the rolling element contacts the raceway surface of the outer ring. Consists of
Said input shaft, said intermediate shaft, and the second transmission mechanism, a composite transmission and the output shaft is characterized that you have arranged coaxially. The intermediate shaft has a power transmission unit that transmits the rotational driving force of the input shaft to the intermediate shaft by engaging with the rolling element and rotating, and the power transmission unit transmits the rolling element. The compound transmission according to claim 1, which is a cage for holding. A third transmission mechanism provided between the output shaft and the second transmission mechanism and transmitting the rotational driving force transmitted from the second transmission mechanism to the output shaft by converting the rotational driving force at a predetermined gear ratio. The combined transmission according to claim 1 or 2, further comprising. The third transmission mechanism is between an inner ring fixed to the carrier of the second transmission mechanism and having a raceway surface, an outer ring having a raceway surface, and the raceway surface of the inner ring and the raceway surface of the outer ring. The power transmission includes a plurality of rolling elements arranged so as to roll in the above, and a power transmission unit that transmits the rotational driving force to the output shaft by engaging with the rolling elements and rotating. parts, said a hold circuit that holds the rolling elements, and the composite transmission according to claim 3 comprising configured integrally with the output shaft. Together provided between the first transmission mechanism and the second transmission mechanism, a third transmit the rotational driving force of the first transmission mechanism and converts at a predetermined speed ratio you transmitted to the second transmission mechanism The compound transmission according to claim 1 or 2, further comprising a mechanism. The third transmission mechanism includes an inner ring fixed to the intermediate shaft of the first transmission mechanism and having a raceway surface, an outer ring having a raceway surface, and the raceway surface of the inner ring and the raceway surface of the outer ring. A plurality of rolling elements arranged so as to roll between them, and an intermediate shaft that transmits the rotational driving force of the first transmission mechanism to the second transmission mechanism by engaging with the rolling elements and rotating. The compound transmission according to claim 5, which includes. A preload mechanism for applying a preload to the third transmission mechanism is provided, and the preload mechanism uses the diameter of the rolling element in the third transmission mechanism as the diameter of the rolling element in the third transmission mechanism so that the rolling element is the raceway surface of the inner ring. The compound transmission according to claim 4 or 6, wherein the contact point to be contacted is set to be larger than the distance between the contact point where the rolling element comes into contact with the raceway surface of the outer ring.

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