JP2006214560A - Planetary roller type reduction gear - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a planetary gear type reduction gear with low vibration and noise capable of providing a wide range of rotations in combination with a servo motor and applicable to the main spindle drive devices of various types of devices and machines. <P>SOLUTION: In this planetary roller type reduction gear using a plurality of planetary roller mechanisms, an external spline is fitted to the rear end part of a first transmission shaft formed by extending rearward the shaft of the carrier of the planetary roller mechanism on the forefront stage forming a next stage input shaft, an external spline is fitted to the rear end part of a cylindrical second transmission shaft formed by externally fitting the shaft of the carrier of the next stage planetary roller mechanism onto the intermediate part of the first transmission shaft, and two internal splines selectively meshed with the external spline of the first transmission shaft and the external spline of the second transmission shaft are fitted to the front part. Also, the reduction gear comprises a selection shaft spline-coupled, at its rear part, with a final output shaft and slidable in the axial direction and a selection shaft drive means axially reciprocating the selection shaft. The selection shaft is moved in the axial direction and the two internal splines of the selection shaft are engaged with either of the external splines of the first and second transmission shafts. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to improvements in reduction gears used in various devices, spindle drive devices for machines, and the like.

  In various devices and machines, there are cases where high-speed and low-torque driving is required, and low-speed and high-torque driving is required. A combination of this motor and a gear-type speed reducer with a variable speed ratio is often used. Recently, it has become possible to handle a wide range of rotational speeds without using a reduction gear, but it is desired to further expand the rotational speed range due to technological advances. It is desired to perform a mechanical shift of about two steps. (For example, patent document 1 (Unexamined-Japanese-Patent No. 6-249304))

  In addition, the output shaft of the servo motor (drive motor) and the input shaft of the reduction gear are joined together by a flange-type fixed joint, hub-type fixed joint, flexible joint, and spline-type joint that uses a key. Is called. (For example, patent document 2 (Unexamined-Japanese-Patent No. 4-39449))

JP-A-6-249304 (FIGS. 1 and 2) Japanese Patent Laid-Open No. 4-39449 (FIG. 3)

  When a gear type reduction gear is used as the main shaft drive device as in Patent Document 1, vibration and noise are generated by the meshing of the gears, and the vibration causes problems in precision machining and the like, and the noise deteriorates the product quality. There is a bug.

  Also, when the servo motor is mounted on the speed reducer and connected together, using the spline joint to connect the servo motor output shaft and the speed reducer input shaft requires special processing on the motor side output shaft. In the flange type and hub type, it is difficult to adjust the alignment including the mounting of the servo motor, and it is necessary to increase the accuracy of the parts. In addition, the flexible joint has the disadvantages that the alignment is easy but the axial dimension becomes large. is there.

It is a first object of the present invention to provide various devices for obtaining a wide range of rotation in combination with a servo motor, and a low-vibration, low-noise planetary roller speed reducer that can be applied to a spindle drive device of a machine. Yes.
In addition, the present invention does not impose a special specification on the output shaft of the servo motor, it is easy to align even if the precision of related parts is moderated, and the servo motor is connected by a joint having a short axial length. The second object is to provide a planetary roller type speed reducer integrated with the above.

In order to solve the above problems, the following means are used to solve the problems.
(1) A planetary roller type speed reducer in which the input shaft is coupled via a joint with the output shaft of the servo motor, the inner ring of the speed reducer being fixed, the sun roller shaft as the input shaft, and the planetary pin supported In the planetary roller type speed reducer using a plurality of planetary roller mechanisms that decelerate using the carrier axis as the output shaft, the carrier axis of the foremost planetary roller mechanism serving as the next-stage input shaft is extended backward to the first An outer spline at the rear end portion serving as a transmission shaft, and a carrier shaft of the next stage planetary roller mechanism as a cylindrical second transmission shaft that is fitted around the intermediate portion of the first transmission shaft. A spline, two inner splines that selectively mesh with the outer spline of the first transmission shaft and the outer spline of the second transmission shaft at the front, respectively, and the rear portion splined with the final output shaft in the axial direction A slidable switching shaft and the switching shaft as an axis Switching shaft drive means for reciprocating in the direction, moving the switching shaft in the axial direction, and engaging two inner splines of the switching shaft with one of the outer splines of the first or second transmission shaft A planetary roller type reduction gear.

(2) In the planetary roller type speed reducer described in (1) above, the joint includes a plurality of claws protruding in the axial direction at one end, a joint member fixed to the output shaft of the servo motor, and an input of the speed reducer A plurality of claws integrally formed at one end of the shaft and projecting in the axial direction so as to face the claws of the joint member, and a circumferential direction sandwiched between the claws of the input shaft and the claws of the joint member A planetary roller type speed reducer, which is a plug-in type flexible joint made of an elastic body that transmits the pressing force.
(3) The planetary roller type speed reducer according to (2), wherein the joint member is fixed and the output shaft of the servo motor is fixed by a sink key or a conical ring.

The following effects can be obtained by the planetary roller type speed reducer of the present invention.
(1) The invention according to claim 1 is the planetary roller type speed reducer according to the first means, and since no gear is used, vibration and noise generated by the meshing of the gear can be eliminated, and high precision It is suitable for a spindle driving device for machine tools capable of both machining and heavy cutting.
(2) The invention according to claims 2 and 3 is the planetary roller type speed reducer of the second and third means, wherein the joint connecting the servo motor and the input shaft of the speed reduction device is a plug-in with an elastic body interposed Since the joint of the input side is formed integrally with the input shaft, the input shaft side joint member that is normally required can be omitted, and the axial length can be reduced. In addition to being able to shorten, the accuracy of the related members can be reduced by increasing the geometrical tolerance allowed for the flexible joint.

(First embodiment)
The configuration and operation of the planetary roller speed reducer according to the first embodiment of the present invention will be described with reference to FIGS. 1 and 2 are front sectional views along the axis of the planetary roller type speed reducer at low speed switching and high speed switching, respectively, and FIG. 3 is a left side view of FIGS. 1 and 2 excluding a part of the case. It is.
In these drawings (refer mainly to FIG. 1), reference numeral 1 denotes a case composed of five cylindrical case blocks 1a, 1b, 1c, 1d, 1e. The planetary roller mechanism 10, the second planetary roller mechanism 20, the switching mechanism 30, and the output shaft 40 are incorporated.
The input shaft 5 has a front end (left side in the figure) protruding outside the case 1 and is connected to an output shaft of a servo motor (not shown) by a flange-type fixed joint, a flexible joint, a spline-type joint, etc. The bearing is rotatably supported through the case block 1a (vertical wall) through the bearing, and the rear end is a small-diameter shaft that is rotatably supported by a carrier 15 (described later) via the bearing. A sun roller 11 of the first planetary roller mechanism 10 is formed on the first planetary roller mechanism 10, and the sun roller 11 is a part of the first planetary roller mechanism 10.

  The first planetary roller mechanism 10 is housed in a case block 1b, and includes a sun roller 11, a planetary roller 12 in contact with the sun roller 11, a planetary roller 12 rotatably supported and one end fixed to a carrier 15 described later. The pin 13, the inner ring (outer roller) 14 that contacts the planetary roller 12 on the inner peripheral surface, the carrier 15 that supports the planetary pin 13, and the first transmission shaft 16 that is integrally formed at the center of the carrier 15. Yes.

The first transmission shaft 16 is a slightly long shaft, forms the sun roller 21 of the second planetary roller mechanism 20 at the position of the case block 1c, has an outer spline 17 at the rear end, and includes the case block 1b and the second planetary roller. A carrier 25 of the mechanism 20 is rotatably supported via a bearing, and a front end portion rotatably supports a rear end of the input shaft 5 via a bearing, and a rear end portion is slid via a roller bearing 36. It engages concentrically with a switching shaft 31 described later so as to be movable and rotatable.
In addition, as shown in FIG. 3, the outer peripheral surface of the sun roller 11 and the outer peripheral surface of the planetary roller 12, and the outer peripheral surface of the planetary roller 12 and the inner peripheral surface of the inner ring 14 are in contact with each other by being pressurized. The tangential force is transmitted by friction.

  The second planetary roller mechanism 20 has a structure similar to that of the first planetary roller mechanism 10 and is housed in the case block 1c. The sun roller 21 is formed on the first transmission shaft 16, and the planetary roller 22 and the planetary pin. 23, the inner ring 24, and the carrier 25 are substantially the same as those of the first planetary roller mechanism 10, and the planetary pin 23 is fixed to the carrier 25. A cylindrical second transmission shaft (sleeve shaft) 26 that is integrally formed is provided at the center of the carrier 25, and an outer spline 27 is formed on the outer periphery of the rear end. The carrier-side inner peripheral portion rotatably supports the first transmission shaft 16 via a bearing.

  The switching mechanism 30 is housed in the case block 1d, and includes a switching shaft 31 composed of a two-stage cylindrical portion on the front side and a small-diameter real shaft portion on the rear side, an annular sliding plate 32, and two pieces. The air cylinder 33 for switching is comprised. An inner spline 34 that meshes with the outer spline 27 of the second transmission shaft 26 of the second planetary roller mechanism 20 is formed on the inner diameter side of the front end large-diameter portion of the two-stage cylindrical portion of the switching shaft 31, and the inner portion of the cylindrical portion An inner spline 35 that meshes with the outer spline 17 at the rear end of the first transmission shaft 16 of the first planetary roller mechanism 10 is provided on the inner diameter side of the small diameter portion. 36 is a roller bearing which is held on the switching shaft 31 side at a position between the spline 34 and the spline 35 and is connected to the first transmission shaft 16 so as to be axially slidable and rotatable, and 37 is held on the case block 1d. The roller bearing supports the small-diameter cylindrical portion of the switching shaft 31 in a slidable and rotatable manner. The sliding plate 32 is an annular plate that is slidably fitted in a square groove formed in the outer peripheral portion of the large-diameter cylindrical portion of the switching shaft 31, and is provided with two switching airs fixed to the case block 1d. A moving means for moving the switching shaft 31 to two positions by moving forward and backward in the axial direction by the rod of the cylinder 33 is formed. An outer spline 38 is provided on the real shaft at the rear end of the switching shaft 31.

  The output shaft 40 is supported by the case block 1e so as to be free to rotate while being restrained in the axial direction through a bearing. The rear end protrudes outside the case 1, the front end is cylindrical, and the inner spline 41 is formed on the inner diameter side. And is always meshed with the outer spline 38 of the switching shaft 31.

(Operation at low speed switching)
The operation of the planetary roller speed reducer according to the first embodiment having the above configuration will be described.
First, the case of low-speed switching in which the first and second planetary roller mechanisms 10 and 20 perform two-stage deceleration will be described with reference to FIG.
The switching shaft 31 extends the rod of the switching air cylinder 33 to the maximum stroke position and moves it to the left as shown in FIG. 1 to move the inner spline 34 to the outer spline 27 of the second transmission shaft 26 of the second planetary roller mechanism 20. The inner spline 35 is freely released. When the input shaft 5 is rotated by a servo motor (not shown), the sun roller 11 rotates the planetary roller 12 by friction. However, since the inner ring 14 is fixed, the planetary roller 12 is instantaneously centered on the contact point with the inner ring 14. As reverse rotation. Due to this reverse rotation, the planetary roller 12 returns back to the circumferential surface of the sun roller 11, and the planetary pin 13, and thus the carrier 15 and the first transmission shaft 16 integrated therewith, rotate in the same direction with a delay from the input shaft 5. The speed is reduced at a reduction ratio determined by the diameters of the roller 11 and the planetary roller 12. The sun roller 21 integrated with the first transmission shaft 16 serves as an input shaft of the second planetary roller mechanism 20, and outputs the rotation that has been decelerated and decelerated two steps in the same manner as the first planetary roller mechanism 10 to the second transmission shaft 26. The second output shaft 26 transmits the rotation from the outer spline 27 to the switching shaft 31 via the inner spline 34, and the switching shaft 31 transmits the rotation from the outer spline 38 to the output shaft 40 via the inner spline 41. The rotation direction of the output shaft 40 is the same as that of the input shaft 16.

(Operation at high speed switching)
Next, the case of high-speed switching that performs one-stage deceleration using only the first planetary roller mechanism 10 will be described with reference to FIG.
The switching shaft 31 contracts the rod of the switching air cylinder 33 to the minimum stroke position and moves it to the right as shown in FIG. 2 to move the inner spline 34 to the outer spline 27 of the second transmission shaft 26 of the second planetary roller mechanism 20. The inner spline 35 is engaged with the outer spline 17 at the rear end of the first transmission shaft 16.
When the input shaft 5 is rotated by the servo motor, the rotation decelerated by the first planetary roller mechanism 10 is transmitted from the outer spline 17 at the tip of the first transmission shaft 16 to the switching shaft 31 through the inner spline 35 meshing with the rotation. The switching shaft 31 transmits the rotation reduced by one step from the outer spline 38 to the output shaft 40 through the inner spline 41. The rotation direction of the output shaft 40 is the same as that of the input shaft 16. In this deceleration operation, the second planetary roller mechanism 20 is idling.
In this device, since the high reduction speed is not switched during the high-speed rotation, the spline meshing of the switching shaft 31 is easily performed during the low-speed rotation at the start if the switching air cylinder 33 is operated. .

(Second Embodiment)
A planetary roller type speed reducer according to a second embodiment of the present invention will be described with reference to FIGS. The feature of the second embodiment is a plug-in type (plug-in type) joint that connects the output shaft of the servo motor and the input shaft of the speed reducer. In the figure, the same member as that of the first embodiment is used. Are given the same numbers and their explanation is omitted.
4 is a partial cross-sectional view (enlarged view) in which a servo motor is attached to the left side of FIG. 1, FIG. 5 is a cross-sectional view taken along line AA in FIG. 4, FIG. 6 is a perspective view of a joint portion, and FIG. It is a perspective view of joint member 61A applied to a round shaft in which an output shaft does not have a key instead of member 61.

In FIG. 4, 50 is a general-purpose servo motor, 1f is a case block having a cylindrical portion 1g protruding to attach the servo motor 50 to the left side of the case block 1a (see FIG. 1). The portion 50a is fitted into the tip inner diameter portion 1h of the cylindrical portion 1g of the case block 1f, and the flange portions 50b and 1i are coupled by bolts 54.
51 is an output shaft of the servo motor 50, 55 is an input shaft formed integrally with the sun roller 11 of the first planetary roller mechanism 10, and 60 is a flexible joint for connecting the output shaft 51 of the drive motor 50 and the input shaft 55. .
The output shaft 51 is generally a round shaft or with a key as a standard shaft, and FIG. 4 shows a case with a key. 51a is a key groove, and 52 is a sinking key fitted in the key groove 51a.

  The flexible joint 60 includes a joint member (hub) 61 or 61 </ b> A fixed to the output shaft 51 of the servomotor 50, an elastic body 62, and a later-described claw 55 b provided at the tip of the input shaft 55. As shown in FIG. 6, the joint member 61 is cylindrical and has a key groove 61a on the inner diameter side, and has a plurality of (four in the figure) claws 61b protruding in the axial direction on the outer diameter side. It is fixed to the attached output shaft 51 by a set screw 53 via a sink key 52. The joint member 61A is used when the output shaft 51 is a round shaft without a key. As shown in FIG. 7, a cylindrical member 61c having a claw 61b on one side of a cylinder and a small-diameter conical cylinder 61f on the other side is provided. The conical ring 61d fitted to the outside of the conical cylinder 61f is tightened with a pillow head bolt 61e to reduce the inner diameter of the conical cylinder 61f and to be fixed to the output shaft 51 by friction.

Reference numeral 62 denotes a spider-shaped elastic body made up of a plurality of partition walls 62b extending in the radial direction around a thin tube 62a made of NBR, polyurethane, bronze or the like and having a spindle-shaped cross section.
The input shaft 55 is a shaft having a large diameter corresponding to the input shaft 5 integrated with the sun roller 11 of the first embodiment, and the outer peripheral portion thereof is rotatably supported by the case block 1f via the bearing 56, and is centered. A hole 55a for loosely fitting the output shaft 51 of the servomotor 50 and a plurality of (four in the figure) claws 55b projecting in the axial direction are provided at the outer tip (left side in the figure). Form a part of The hole 55a accommodates the tip of the output shaft 51 of the servo motor 50 with a gap, and 55c is a groove for a retaining ring 57 (see FIG. 4) for regulating the position of the bearing 56.

The operation of the second embodiment having the above configuration will be described.
The output shaft 51 of the servo motor 50 and the input shaft 55 of the speed reducer are coupled by a flexible joint 60. The operation of the planetary roller type speed reducer combined with the servo motor 50 is as described in the first embodiment, and the description thereof is omitted.
A joint member 61 is attached to the output shaft 51 of the servo motor 50 when the output shaft 51 has a sinking key 52, and a joint member 61A is attached when the output shaft 51 is a round shaft without the key 52. The attachment position of the joint member 61 or 61A in the axial direction is such that when the stepped portion 50a of the base portion of the servo motor 50 is fitted and attached to the inner diameter portion 1h of the case block 1f, the joint member 61 or 61A has a claw 61b. An appropriate gap is formed in the axial direction so that the tip does not interfere with a member in the vicinity of the root portion of the claw 55b of the input shaft 55. Since this gap can be made relatively large, the accuracy of the mounting position need not be strict.

  An elastic body 62 is mounted at a fixed position between the claw 61b of the joint member 61 or 61A fixed to the output shaft 51 of the servomotor 50, and the claw 55b of the input shaft 55 enters between the partition walls 62b of the elastic body 62. Create and place a space. The servomotor 50 is fitted to the female screw of the flange portion 1i with a bolt 54 through the hole of the flange portion 50b with the step portion 50a of the base portion fitted into the inner diameter portion 1h of the case block 1f. When the servo motor 50 is mounted, the output shaft 51 is guided in the hole 55a of the input shaft 55, but both are loosely fitted with a relatively large gap and interfere with each other in a direction perpendicular to the shaft. Rather, the claw 55b at the tip of the input shaft 55 enters and fits in the space between the claw 61b of the joint member 61 or 61A and the partition wall 62b of the elastic body 62. The corners of the claw 55b, the claw 61b, and the partition 62b in the axial direction are chamfered so as to easily slip when they approach each other.

  The relative position and orientation of the output shaft 51 of the servo motor 50 and the input shaft 55 of the speed reducer are determined by the step portion 50a of the base portion of the servo motor 50 and the inner diameter portion 1h of the case block 1f. Since the joint 60 is configured to transmit torque via the elastic body 62, the geometrical tolerance for the concentricity and inclination of the output shaft 51 of the servo motor 50 and the input shaft 55 of the speed reducer is relatively high. It can be made large, the processing accuracy of the related members can be moderated, and there is no particular need to adjust the alignment during assembly. Further, only one of the joint members (hubs) of the flexible joint 60 is formed integrally with the tip of the input shaft 55, and the extra length of the output shaft 51 of the servo motor 50 is the hole 55a of the input shaft 55. The distance between the servo motor 50 and the speed reducer can be reduced.

It is front sectional drawing along the axis line at the time of the low speed switching of the planetary roller type reduction gear which concerns on the 1st Embodiment of this invention. It is front sectional drawing along the axis line at the time of the high speed switching of the planetary roller type reduction gear which concerns on the 1st Embodiment of this invention. FIG. 2 is a left side view excluding a part of the case of FIG. 1. It is a fragmentary sectional view which shows the connection state of the servomotor and planetary roller type reduction gear which concern on the 2nd Embodiment of this invention. It is AA sectional drawing of FIG. It is the perspective view which made some flexible joints sectional drawing. 7 is a perspective view of a joint member 61A applied to a round shaft in which the output shaft 51 does not have a key instead of the joint member 61 of FIG.

Explanation of symbols

10 First planetary roller mechanism
11 Sun roller shaft 13 Planetary pin 14 Inner ring
16 First transmission shaft 17 Outer spline
20 Second planetary roller mechanism
23 Planetary pin
24 Inner ring 26 Second transmission shaft
27 Outer spline 31 Switching shaft 32 Sliding plate 33 Switching air cylinder
34 Inner spline 35 Inner spline
38 Outer spline 40 Output shaft
41 Inner spline
50 Servo motor 51 Output shaft
52 Sink Key
55 Input shaft 55b Claw 60 Flexible joint
61, 61A Joint member
61b Claw 61c Cylindrical member 61d Conical ring 62 Elastic body

Claims (3)

A planetary roller type speed reducer in which an input shaft is coupled via an output shaft and a joint of a servo motor, the inner ring of the speed reducer being fixed, a sun roller shaft as an input shaft, and a carrier supporting a planetary pin In the planetary roller type speed reducer using a plurality of planetary roller mechanisms that decelerate with the shaft as an output shaft, the carrier shaft of the foremost planetary roller mechanism serving as the input shaft for the next stage is extended rearward and the first transmission shaft An outer spline at the rear end portion, and an outer spline at the rear end portion as a cylindrical second transmission shaft that externally fits the shaft of the carrier of the planetary roller mechanism of the next stage to the intermediate portion of the first transmission shaft, Two inner splines selectively engaged with the outer spline of the first transmission shaft and the outer spline of the second transmission shaft at the front portion, and the rear portion is splined with the final output shaft so as to be slidable in the axial direction. Switching axis and the switching axis in the axial direction Switching shaft drive means for moving back, moving the switching shaft in the axial direction, and engaging the two inner splines of the switching shaft with one of the outer splines of the first or second transmission shaft. Planetary roller speed reducer characterized by   The planetary roller type speed reducer according to claim 1, wherein the joint includes a plurality of claws protruding in the axial direction at one end, a joint member fixed to the output shaft of the servo motor, and one end of the input shaft of the speed reducer. A plurality of claws that are integrally formed and project in the axial direction so as to face the claws of the joint member, and are sandwiched between the claws of the input shaft and the claws of the joint member so as to apply a circumferential pressing force to each other. A planetary roller type speed reducer characterized in that it is a plug-in type flexible joint comprising an elastic body for transmission.   3. The planetary roller type speed reducer according to claim 2, wherein the joint member fixes the output shaft of the servo motor by a sink key or a conical ring.

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