JP2004176831A - Planetary roller type reduction gear - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a planetary roller type reduction gear with low vibration and low noise which can be applied to a main spindle driver of a machine tool for providing a wide range of rotation by combination with a servomotor. <P>SOLUTION: The planetary roller type reduction gear has two internal splines respectively selectively meshing with an external spline of an upstream transmission shaft and an external spline of a terminal transmission shaft, an axially slidable change-over shaft spline-connecting to a terminal output shaft is provided in a rear part, the change-over shaft is axially moved by a moving means for reciprocating a slide plate slidably fit in a groove provided in an outer circumference part of the change-over shaft by a cylinder, and the internal splines of the change-over shaft are meshed with either one of the external splines of the upstream or terminal transmission shaft. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an improvement of a planetary roller type reduction gear used for a spindle drive device of a machine tool or the like.
[0002]
[Prior art]
In machine tools, planetary rollers are frequently used to suppress vibrations that adversely affect machining accuracy.If a large reduction ratio is required, a multi-stage planetary roller type reduction gear that connects multiple planetary rollers is used. (For example, see Patent Document 1).
[0003]
Depending on the processing method and the characteristics of the workpiece, there are cases where high-speed low-torque cutting is required and cases where low-speed high-torque cutting is required. In many cases, a combination of a speed reducer with a variable speed ratio is used (for example, see Patent Document 2). Recently, it has become possible to cope with a considerably wide range of rotation speed without using a reduction gear by a servomotor, but with the advancement of technology, it is desired to further expand the rotation speed range of a planetary roller type reduction gear. Even if a servomotor is used, it is still necessary to mechanically shift about two steps.
[0004]
[Patent Document 1]
JP-A-2002-257205 (page 4, FIG. 1)
[Patent Document 2]
JP 2002-310246 A (page 4-6, FIG. 1)
[0005]
[Problems to be solved by the invention]
When a gear type reduction gear is used for the main shaft drive, vibration and noise are generated due to meshing of the gears, and the vibration causes a problem in precision of precision machining, lowers product quality and causes noise. was there.
[0006]
The present invention has been made in order to solve the problem caused by such vibration, and has low vibration and low noise which can be applied to a spindle drive device of a machine tool for obtaining a wide range of rotation in combination with a servomotor. It is an object of the present invention to provide a planetary roller type speed reducer.
[0007]
[Means for Solving the Problems]
(1) A planetary roller mechanism including a fixed inner ring, a planetary roller meshing with the inner ring, an input shaft including a sun roller meshing with the planetary roller, and a carrier supporting the shaft of the planetary roller. Are connected in a plurality of stages, a planetary roller type reduction gear of the final stage, a final transmission shaft having a first engaging means provided at a rear end portion, and a driving force applied to the planetary roller mechanism of the final stage. The upstream transmission shaft provided with a second engagement means at the rear end, and the engagement means of each of the final transmission shaft and the upstream transmission shaft. A switching shaft slidable in the axial direction provided with a third engaging means for engaging; and switching means for sliding the switching shaft in the axial direction, the switching means sliding the switching shaft in the axial direction. Moving the third engagement means to the first engagement means. It is characterized in that selectively engaging with any of the engaging means of the second engagement means.
[0008]
(2) In the planetary roller type speed reducer according to (1), the switching shaft is provided with fourth engagement means capable of engaging with a final output shaft to which an output from the planetary roller type speed reducer is transmitted. It is characterized by being provided.
[0009]
(3) In the planetary roller type speed reducer according to any one of (1) and (2), the third engagement means is selectively connected to one of the first engagement means and the second engagement means. 3. The planetary roller type speed reducer according to claim 1, wherein the speed reducer is a spline mechanism that can be switched and engaged with the planetary roller type.
[0010]
(4) The drive source of the switching means is a cylinder.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the planetary roller type speed reducer of the present invention will be described with reference to FIGS. 1 and 2 are longitudinal sectional views along an axis of an embodiment of a planetary roller type speed reducer at the time of low speed switching and high speed switching, respectively, and FIG. 3 is a front view excluding a part of a case.
[0012]
In these drawings (refer mainly to FIG. 1), a case 1 is composed of five cylindrical case blocks 1a, 1b, 1c, 1d, and 1e, and each case block includes an input shaft 5 and a first planet from the left side. The roller mechanism 10, the second planetary roller mechanism 20, the switching mechanism 30, and the output shaft 40 are incorporated.
[0013]
The input shaft 5 has a front end (left side in the figure) protruding out of the case 1 and a body part rotatably supported by penetrating a case block 1a (flange) through two bearings, and a rear end. A small diameter shaft is rotatably supported by a carrier 15 described later via a bearing. The sun roller 11 of the first planetary roller mechanism 10 is formed between the input shaft 5 and the small diameter shaft, and the sun roller 11 is a part of the first planetary roller mechanism 10.
[0014]
The first planetary roller mechanism 10 is housed in the case block 1b, and includes a sun roller 11, a planetary roller 12 that comes into contact with the sun roller 11, and a planetary pin that rotatably supports the planetary roller 12 and has one end fixed to a carrier 15 described later. 13, an inner ring (outer roller) 14 which is in contact with the planetary roller 12 on the inner peripheral surface and is supported by the case block 1b, and a first transmission shaft 16 integrally formed at the center of the carrier 15.
[0015]
The first transmission shaft 16 forms the sun roller 21 of the second planetary roller mechanism 20 at the position of the case block 1c, has the outer spline 17 at the rear end, and has the case block 1b and the carrier of the second planetary roller mechanism 20. The front end of the input shaft 5 is rotatably supported via a bearing, and the rear end of the input shaft 5 is slidably and rotatable via a roller bearing 36. Are engaged concentrically with a switching shaft 31 described later.
[0016]
3, the outer peripheral surface of the sun roller 11 and the outer peripheral surface of the planetary roller 12, the outer peripheral surface of the planetary roller 12, and the inner peripheral surface of the inner ring 14 are pressurized and in contact with each other as shown in FIG. The tangential force is transmitted by friction.
[0017]
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 described above. The planetary roller 22, 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 is provided integrally at the center of the carrier 25, and an outer spline 27 is formed at the outer periphery of the rear end. The case block 1c uses a bearing via a bearing. The first transmission shaft 16 is rotatably supported by a carrier-side inner peripheral portion via a bearing.
[0018]
The switching mechanism 30 is housed in the case block 1d. It comprises a switching shaft 31 composed of a cylindrical portion having a step in two steps on the front side and a real shaft part of a small diameter on the rear side, an annular sliding plate 32 and two cylinders 33. 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 provided on the inner diameter side of the large-diameter portion at the front end of the two-stage cylindrical portion of the switching shaft 31. 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.
[0019]
The bearing 36 is a roller bearing which is held on the switching shaft 31 side at a position between the inner spline 34 and the inner spline 35, and is slidably and rotatably connected to the first transmission shaft 16 in the axial direction. Reference numeral 37 denotes a roller bearing which is held by the case block 1d and slidably and rotatably supports the small-diameter cylindrical portion of the switching shaft 31.
[0020]
The sliding plate 32 is an annular plate slidably fitted in a square groove formed on an outer peripheral portion of a large-diameter cylindrical portion of the switching shaft 31, and includes two cylinders 33 fixed to the case block 1d. Moving means for moving the switching shaft 31 to two positions by moving forward and backward in the axial direction by the rod is formed. An outer spline 38 is provided on the real shaft portion at the rear end of the switching shaft 31.
[0021]
The output shaft 40 is rotatably supported with the axial movement restricted by a case block 1e via a bearing. The rear end of the output shaft 40 projects out of the case 1, and the front end has a cylindrical shape. And is always engaged with the outer spline 38 of the switching shaft 31.
[0022]
The cylinder 33 is operated by a working fluid such as oil or air, and the operation of the cylinder 33 is performed manually or by electrical control.
[0023]
The operation of the planetary roller type speed reducer having the above configuration will be described. First, the case of low-speed switching in which two-stage deceleration is performed using both the first planetary roller mechanism 10 and the second planetary roller mechanism 20 will be described with reference to FIG.
[0024]
The switching shaft 31 extends the rod of the cylinder 33 to the maximum stroke position and moves it to the left as shown in FIG. 1 so that the inner spline 34 meshes with 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, but since the inner ring 14 is fixed, the contact point between the planetary roller 12 and the inner ring 14 is instantaneously centered. As reverse rotation. Due to this reverse rotation, the planetary roller 12 returns to the peripheral surface of the sun roller 11, and the planetary pin 13, and thus the carrier 15 and the first transmission shaft 16 integral therewith, rotate in the same direction behind the input shaft 5, and 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 a rotation that is reduced by two steps and reduced by two steps to the second transmission shaft 26, similarly to the first planetary roller mechanism 10. The second transmission shaft 26 transmits rotation from the outer spline 27 to the switching shaft 31 via the inner spline 34, and the switching shaft 31 transmits 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 5.
[0025]
Next, a case of high-speed switching in which one-step deceleration is performed using only the first planetary roller mechanism 10 will be described with reference to FIG.
[0026]
The switching shaft 31 contracts the rod of the cylinder 33 to the minimum stroke position and moves it to the right as shown in FIG. 2 to release the inner spline 34 from 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.
[0027]
When the input shaft 5 is rotated by the servo motor, the rotation reduced 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 via the inner spline 35 meshing therewith. The switching shaft 31 transmits the one-stage reduced 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 opposite to that of the input shaft 5. In this deceleration operation, the second planetary roller mechanism idles.
[0028]
In this device, the switching of the high reduction speed is not performed during the high-speed rotation, so that the engagement of the splines of the switching shaft 31 can be easily performed during the low-speed rotation at the start by using the cylinder 33.
[0029]
The embodiment described above is an example of a two-stage speed reducer, but the number of planetary roller mechanisms may be three or more.
[0030]
Further, as another embodiment, the diameter of the front end of the switching shaft is inserted into the rear end cylinder of the second transmission shaft, and the spline formed at the end of the switching shaft has the inside and outside relative to the previous embodiment. It is needless to say that the same operation and effect can be obtained even with the exchanged form.
[0031]
Further, instead of a mechanical device using the cylinder 33, a manual device via a lever or a link may be used.
[0032]
【The invention's effect】
The following effects can be obtained by the planetary roller type speed reducer of the present invention. That is, it is possible to provide a low-vibration, low-noise planetary roller type reduction gear device applicable to a spindle drive device of a machine tool for obtaining a wide range of rotation in combination with a servomotor.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view taken along an axis at the time of low-speed switching of a planetary roller type speed reducer of the present invention.
FIG. 2 is a longitudinal sectional view along an axis at the time of high-speed switching of the planetary roller speed reducer of the present invention.
FIG. 3 is a front view excluding a part of the case of FIG. 1;
[Explanation of symbols]
5 input shaft 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 ... Cylinder 34 ... Inner spline 35 ... Inner spline 36 ... Bearing 37 ... Bearing 38 ... Outer spline 40 ... Output shaft 41 ... Inner spline

Claims (4)

A planetary roller mechanism including a fixed inner ring, a planetary roller meshing with the inner ring, an input shaft including a sun roller meshing with the planetary roller, and a carrier supporting the shaft of the planetary roller is provided in a plurality of stages. In the connected planetary roller type reducer,
A final transmission shaft, wherein the final stage planetary roller mechanism is provided with first engagement means at a rear end;
An upstream transmission shaft which is a planetary roller mechanism immediately before transmitting the driving force to the planetary roller mechanism at the last stage, the upstream transmission shaft having a second engagement means provided at a rear end;
A switching shaft slidably provided in an axial direction by providing third engagement means for selectively engaging the respective engagement means of the final transmission shaft and the upstream transmission shaft;
Switching means for sliding the switching shaft in the axial direction,
By sliding the switching shaft in the axial direction by the switching means, the third engaging means is selectively connected to either the first engaging means or the second engaging means. A planetary roller type speed reducer, wherein The planetary roller type according to claim 1, wherein the switching shaft is provided with fourth engagement means capable of engaging with a final output shaft to which an output from the planetary roller type speed reducer is transmitted. Decelerator. 3. The spline mechanism according to claim 1, wherein the third engaging means is a spline mechanism that can selectively switch and engage with any one of the first engaging means and the second engaging means. The planetary roller type speed reducer according to claim 7. 4. The planetary roller type speed reducer according to claim 1, wherein a drive source of the switching means is a cylinder.

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