JPH06272745A - Frictional epicyclic roller-type reduction gear - Google Patents

Abstract

PURPOSE:To manufacture a frictional epicyclic roller-type reduction gear at a low cost without troubles such as defective rotation and defective frictional contact due to an installing error in the auto-rotation shaft of an epicyclic roller or the like. CONSTITUTION:This frictional epicyclic roller-type reduction gear 1 is provided with steel balls 6 on a market as an epicyclic roller. The steel rollers are clipped by a pair of side plates 7, 8 from both sides under a prescribed pressure. The steel balls 6 are disposed between the outer peripheral surface 5a of a sun roller 5 on one side and a fixed ring member 11 and an output ring member 12 on the other side under a rolling-frictional contact condition. The fixed ring member 11 presses the steel balls 6 to the sun roller 5 side at a prescribed pre-load with a pre-load spring 14. When the sun roller 5 rotates, deceleration rotation is outputted from the output ring member 12 by the epicyclic movement of the steel balls 6 mainly. It is possible to eliminate the auto-rotation shaft of the epicyclic roller and so forth, and solve problems caused by the installing error and the like, and prevent backlash from occurring.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a friction planetary roller reducer, and more particularly to a friction planetary roller reducer having a structure in which spherical rolling elements such as steel balls are used as the planetary rollers. is there.

[0002]

2. Description of the Related Art A friction planetary roller type speed reducer is in frictional contact with a sun roller, a plurality of planetary rollers frictionally contacted with the outer periphery of the sun roller and rotatably and revolvably supported by a carrier, and these frictional rollers. It is basically composed of a fixed annular member having a circular inner peripheral surface. An input shaft is connected to the sun roller, and an output shaft is connected to the carrier.
When the sun roller is rotated at high speed, the known deceleration principle
Decelerated rotation is obtained from the output shaft side via the carrier.

[0003]

In such a speed reducer, if the machining accuracy of the planetary roller or the like and its mounting accuracy on the rotating shaft are poor, the rotation of the planetary roller may be poor due to rattling, or the sun roller and the planetary gear may not be mounted properly. Problems such as the inability to ensure proper frictional contact between the rollers occur. Therefore, it is necessary to process each member with high precision.
Since it is necessary to mount each member accurately, manufacturing of such a speed reducer requires considerably high technology, and the manufacturing cost tends to be high.

In view of such a point, an object of the present invention is to
To propose a friction planetary roller reducer that can be maintained at an uncentered state without attaching a rotation shaft to the planetary roller, avoid the occurrence of problems due to processing and mounting accuracy of the planetary roller, and can be manufactured at low cost. It is in.

[0005]

In order to solve the above-mentioned problems, a friction planetary roller type speed reducer of the present invention comprises a sun roller which rotates integrally with an input shaft, and an outer peripheral surface of the sun roller which is an orbital surface for rotation. And a plurality of spherical rolling elements arranged in a revolvable state, and a fixed annular member having a tapered inner peripheral surface for pressing the spherical rolling elements from the input shaft side toward the sun roller side, A preload means for applying a preload to the fixed annular member, and an output annular member having a tapered inner peripheral surface that is in frictional contact with the spherical rolling element from the opposite side of the fixed annular member with the spherical rolling element interposed therebetween. An output shaft connected so as to rotate integrally with the output annular member, and rolling element holding means for sandwiching the spherical rolling element from both sides in the axial direction with a predetermined pressing force in a state where it can rotate and revolve. Adopt a configuration that has There. The rolling element holding means is composed of a pair of side plates that sandwich the spherical rolling element from both sides in the axial direction, and a pressing means that presses these side plates against the spherical rolling element side with a predetermined force. It is configured.

Here, as the constitution of the pressing means of the side plate, the following can be adopted. For example, as the side plate, a plate spring-like plate that is elastically deformable in the out-of-plane direction is used, and these side plates are tightened with a predetermined force with a fastening member composed of bolts, nuts, etc. The spherical rolling element may be clamped with a predetermined force by utilizing the elastic force of the plate. Alternatively, the pair of side plates may be tightened using extension bolts, and a predetermined pressing force may be applied to the pair of side plates by the extension elasticity of the extension bolts. Alternatively, an elastic member such as a spring or a wave washer may be separately arranged, and a pressing force may be applied to the side plate by the elastic deformation force of the elastic member.

Next, the friction planetary roller reducer can be constructed as follows without using the side plate and pressure. That is, a friction planetary roller type speed reducer, a sun roller that rotates integrally with an input shaft, a plurality of spherical rolling elements that are arranged so as to be able to rotate and revolve with the outer peripheral surface of the sun roller as a raceway surface, and these spherical rollers. A fixed annular member having a tapered inner peripheral surface that is in frictional contact with the rolling element from the side of the input shaft, and a frictional contact with the spherical rolling element from the opposite side of the fixed annular member sandwiching the spherical rolling element. An output annular member having a tapered inner peripheral surface and an output shaft connected to rotate integrally with the output annular member, and the sun roller is divided into an input shaft side and an output shaft side. Split rollers, and a tapered raceway surface in which spherical rolling elements are in frictional contact is formed on the outer peripheral surfaces of these rollers, and further, while supporting the roller on one side so as to be movable in the axial direction, This is the pressing means Therefore, it is sufficient to the side of the spherical rolling element so as to press with a predetermined force.

[0008]

In the friction planetary roller type speed reducer of the present invention, when the sun roller is rotated at a high speed through the input shaft, the spherical rolling element frictionally in contact with the sun roller is sandwiched by the side plates with a predetermined pressure from both sides. Therefore, it rotates and revolves around the sun roller together with the side plate. Since the spherical rolling element is pressed against the output annular member side by the fixed annular member, decelerated rotation is taken out from the output shaft side via the output side annular member by the planetary motion of the spherical rolling element. As described above, the spherical rolling element performs a rotating motion with the pair of side plates being clamped without attaching a rotating shaft or the like as in the conventional case. Further, as the spherical rolling element, a commercially available steel ball can be used as it is. Therefore, the friction planetary roller type speed reducer is configured without being affected by the mounting accuracy of the rotation axis of the planetary roller and the processing accuracy of the planetary roller.

Further, in the friction planetary roller type speed reducer provided with the two-part split type sun roller according to the present invention, the spherical rolling elements are rotated and revolved while being sandwiched by the split type sun rollers from both sides in the axial direction. Do exercise. Even in this case, the friction planetary roller type speed reducer is constructed without being affected by the mounting accuracy of the rotation axis of the planetary roller, the processing accuracy of the planetary roller and the like as in the conventional case.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

First Embodiment FIG. 1 is a schematic vertical sectional view of a friction planetary roller reducer according to a first embodiment of the present invention. The speed reducer 1 of this example includes a cylindrical housing 2, an input shaft 3 extends rotatably through one end surface of the housing 2, and an output shaft 4 rotatably extends through the other end surface. It is extended. A sun roller 5 is integrally formed coaxially with the inner end of the input shaft 3. The shaft 5b extending from the other end surface of the sun roller 5 is rotatably supported by the inner end portion of the output shaft 4 via a bearing. On the outer peripheral surface of the sun roller 5, a raceway surface (friction contact surface) 5a of a steel ball 6 that functions as a planetary roller is formed. The raceway surface 5a of this example has a curved cross section that can circumscribe the outer peripheral surface of the steel ball 6.

A plurality of steel balls 6 are arranged on the outer circumference of the sun roller 5 at regular angular intervals. In this example, those steel balls 6 are generally commercially available. These steel balls 6 are sandwiched by a pair of annular side plates 7 and 8 from both sides in the direction of the axis 1a.
Then, these side plates 7, 8 are tightened with a predetermined pressure by fastening bolts 9 at positions between the steel balls 6, and the fastening force of these bolts 9 causes the steel balls 6 to be attached to the side plates 7, 8 respectively. It is sandwiched with a certain pressure from both sides.

On the outer side of the steel balls 6 in the radial direction, a fixed annular member 11 and an output annular member 12 are arranged in frictional contact with the outer peripheral surface of each steel ball. The fixed annular member 11 is arranged on the side of the input shaft with respect to the steel balls 6, and has a tapered arc-shaped cross section 11 capable of making point contact with the outer peripheral surface of each steel ball 6 on its inner peripheral surface.
a is formed. The output annular member 12 is disposed on the output shaft side with respect to the steel balls 6, and has an inner peripheral surface formed with a tapered arc-shaped cross section 12a capable of making point contact with the outer peripheral surface of each steel ball 6. Here, the fixed annular member 11 is attached to a support annular member 13 which is attached to the housing inner peripheral surface 2a so as to be movable only in the axial direction, and the back surface of the support annular member 13 and the housing input side end surface 2b. A preload spring 14 is arranged between them in a compressed state. This preload spring 14
The fixed annular member 11 presses each steel ball 6 toward the sun roller 5 with a predetermined force by the spring force of. On the other hand, the output annular member 12 side is fixed to the end of an annular member 15 attached to the inner end of the output shaft 4 so as to rotate integrally therewith.
A thrust bearing 16 is arranged between the back surface of the annular member 15 and the housing inner end surface 2c.

Here, in the speed reducer 1 of this embodiment, the pressing force P of the steel ball 6 by the pair of side plates 7 and 8 is set as follows. This will be described with reference to FIG. 2. The pressing force P is at least large enough to prevent the steel ball 6 from rotating on other than the pressure shaft 6a. Further, the upper limit of the pressing force P is regulated by the preload F from the fixed annular member 11 side so that the steel balls 6 can freely move in the radial direction.

In the speed reducer 1 of this embodiment, when the input shaft 3 is rotated by a high speed rotation source such as a motor, the sun roller 5 rotates at high speed. Each steel ball 6 which is in contact with the raceway surface 5a formed on the outer peripheral surface of the sun roller 5 is sandwiched by the side plates 7 and 8 from both sides by the pressing force P. Therefore, each steel ball 6 rotates about the pressure shaft 6a connecting the contact points of the side plates 7 and 8 in the opposite direction to the sun roller 5 and is concentric with the sun roller 5 in the same direction. The orbital motion is performed together with the side plates 7 and 8. Since each steel ball 6 performing the planetary motion is in rolling frictional contact with the output annular member 12, the output annular member 12 decelerates and rotates in the opposite direction to the sun roller 5, and this decelerated rotation causes the output shaft 4 to rotate. Taken from. Further, in this example, if the diameter of the rolling orbit circle for the fixed annular member 11 of the steel ball 6 and the diameter of the rolling orbit circle for the output annular member 12 are different, the circumferential difference between these orbital circles is set. The deceleration by the differential mechanism according to is also obtained.

In the speed reducer 1 of the present embodiment thus configured, unlike the conventional friction planetary roller type speed reducer, there is no error in mounting the planetary roller rotation shaft, or error in mounting the planetary roller on the rotation shaft. Therefore, problems such as poor rotation and poor frictional contact do not occur. Further, in this example, since a commercially available steel ball is used as the planetary roller, the speed reducer can be manufactured at low cost.

Here, as the planetary roller, for example, as shown in FIG. 3, it is also possible to use a steel ball having a shape in which both sides are ground. In this case, the planet rollers 6A are rotated by the side plates 7 and 8 so that the planet rollers 6A rotate only in the rolling direction (only about the b axis).
Need to be clamped from both sides. That is, the planetary roller 6A needs to rotate about the b-axis, but since the frictional contact positions with the fixed annular member 7 and the output annular member 8 are different, the c-axis or each annular member 7, The contact point with 8 tries to rotate around the vertical axis. The side plates 7 and 8 are required to prevent such rotation and to take out only the rotation around the b-axis. Furthermore, in order to perform such a rotation movement, a minute clearance e is provided between the side plates 7 and 8 and the planetary roller 6A.
is necessary. Compared to the case of using such a planetary roller 6A, the advantages of using the commercially available steel ball 6 like the speed reducer 1 of this example are as follows.

First, since it can be used without requiring additional work such as grinding a commercially available steel ball, it is possible to suppress a rise in the manufacturing cost. Further, it is not necessary to consider the accuracy of such additional machining.

Further, in this embodiment, the steel balls 6 are sandwiched between the side plates 7 and 8 in a point contact state, so that there is no rotational friction loss of the steel balls and the efficiency can be improved. Further, unlike the planetary roller 6A, slippage does not occur between both sides of the planetary roller 6A and the side plates 7 and 8, so that reliability in terms of wearability is improved.

Furthermore, as shown in FIG. 4, when a planetary roller 6A whose both sides are ground is used, a minute clearance e in the axial direction formed between the side plates 7 and 8 and the planetary roller 6A. As a result, the planetary rollers are skewed and become a dead zone until the end faces of the planetary rollers come into contact with the side plates, which may lead to backlash of the speed reducer. On the other hand, in the speed reducer 1 of this example, the steel balls 6 and the side plates 7, 8 are
Since there is no need to provide a clearance between them, backlash can be avoided.

Further referring to this backlash point, when the planetary rollers 6A whose both sides are ground are used, it is necessary to accurately set the distance between the side plates 7 and 8 in order to reduce the backlash. . Further, it is necessary to improve the dimensional accuracy of the width of the planetary rollers and minimize the error in the widthwise dimension between the planetary rollers.
In addition to this, as shown in FIG.
Center position 7a in the width direction of each planetary roller 6A between 8
It is necessary to improve the accuracy of distribution from. Otherwise, these errors will lead to increased backlash. On the other hand, in the case of the structure in which the steel balls 6 are directly sandwiched between the side plates 7 and 8 as in this example, such accuracy control is unnecessary, and backlash does not occur. .

Next, as the structure for applying the pressing force P of the steel ball 6 to the side plates 7 and 8, the following structure can also be adopted.

First, in the structure shown in FIG. 6, side plates 7 and 8 having a leaf spring-like characteristic that can be elastically deformed in the out-of-plane direction are used. , 8 are elastically deformed so that a predetermined pressing force P acts, and are tightened using fasteners 9 such as bolts and nuts.

Instead, as shown in FIG. 7, the side plates 7 and 8 are made of rigid materials, and as the bolts for fastening the side plates, extension bolts 9a whose bolt legs have a small diameter are used. May be adopted. By adjusting the tightening amount of the extension bolt 9a, the pressing force P can be generated by utilizing the extension elastic force of the extension bolt 9a.

In the structure shown in FIG. 8, an elastic body 7C such as a wave washer and a disc spring is attached to the outside of one side plate 7, and this is further pressed from the outside in the axial direction by another plate 7A. .

The structure shown in FIG. 9 has side plates 7, 8
The space is pulled by using a spring 7B.

Instead of these, the side plates 7, 8
A structure in which a spring (a washer, a coil spring, etc.) is inserted under the seating surface of the fastening bolt 9 can also be adopted.

Second Embodiment Next, FIG. 10 shows a schematic vertical section of a friction planetary roller reducer 20 according to a second embodiment of the present invention. In this figure, the portions corresponding to those in FIG. 1 are designated by the same reference numerals, and their description will be omitted below. In the speed reducer 20 of this example, instead of using the side plates 7 and 8, the sun roller 5 is composed of a first sun roller piece 51 and a second sun roller piece 52 which are divided into two in the axial direction. The thing is adopted. In detail,
The first sun roller piece 51 on the input shaft 3 side is supported so as to rotate integrally with the outer circumference of the input shaft 3 while being movable in the axial direction. A taper surface 51a is formed on which the steel ball 6 can roll and make frictional contact. The sun roller piece 51 is pressed from the input side to the steel ball 6 side with a predetermined force by the preload spring 21.

On the other hand, the sun roller piece 52 located on the side of the other output shaft 4 is fixed to the end of the input shaft 3 so as to rotate integrally therewith, and the steel ball 6 rolls in frictional contact with the outer circumference thereof. A possible tapered surface 52a is formed.

In the speed reducer 20 of this example, the steel balls 6 are
The pressing force of the sun roller piece 51 causes the solar roller piece 51 to be sandwiched between the sun roller pieces 51 and 52 and the annular members 11 and 12. The taper surface formed on the sun roller pieces 51, 52 may be a linear taper surface as shown in the figure, or may be an arcuate taper surface.

In this example, as shown in FIG. 11, the contact angle a between each of the sun roller pieces 51 and 52 and the steel ball 6 is the contact angle between each annular member 11 and 12 and the steel ball 6 b and c. It is set to be larger than. Furthermore, this contact angle a is 9
It is set to less than 0 degrees.

The speed reducer 20 of this embodiment having the above-mentioned structure is
Since the commercially available steel ball 6 can be used as it is and the side plate is not necessary, the manufacturing cost can be reduced.
Further, since there are few contact points between the constituent parts, it can be expected that the reliability is improved accordingly. Furthermore, it is possible to change the speed ratio only by changing the size of the steel ball 6. Therefore, if you prepare commercially available steel balls of various sizes,
It is possible to easily respond to changes in the speed ratio.

Further, in this example, since the preload is applied from the side of the sun roller, the steel balls are skewed around the portion other than the rotating shaft 6a as in the case where the preload is applied from the side of the fixed annular member. There is nothing.

Also in this example, as the pressing means, the method shown in FIGS. 6 to 9 can be adopted.

[0035]

As described above, in the friction planetary roller type speed reducer of the present invention, spherical rolling elements are adopted as the planetary rollers, and these are sandwiched by a pair of side plates with a predetermined pressing force. is doing. Therefore, according to the present invention, it is possible to realize a speed reducer that does not cause a problem due to the mounting accuracy of the rotation axis of the planetary roller, the processing accuracy of the planetary roller, and the like. Further, according to the present invention, since the spherical rolling element is used as the planetary roller, by pressing the side plates from both sides thereof, the rotation axis of the rolling element can be easily defined and a speed reducer without backlash can be realized. Furthermore, since a commercially available steel ball or the like can be used as the spherical rolling element, the speed reducer can be manufactured at low cost.

On the other hand, in the present invention, in the friction planetary roller type speed reducer using the split type sun rollers instead of using the side plates, the number of parts can be reduced and the frictional contact positions between the constituent parts are reduced accordingly. Therefore, it is possible to realize a speed reducer that is highly reliable in terms of wear. Further, the speed ratio can be easily changed by changing the size of the spherical rolling element.

[Brief description of drawings]

FIG. 1 is a schematic vertical cross-sectional view of a friction planetary roller reducer that is a first embodiment of the present invention.

FIG. 2 is a partially enlarged view showing a part of FIG. 1 taken out.

FIG. 3 is an explanatory diagram showing a positional relationship between a side plate and a planetary roller when a planetary roller whose both sides are ground is used.

4 is an explanatory diagram showing a skew of the planetary roller having the configuration of FIG. 3. FIG.

FIG. 5 is an explanatory diagram showing a distribution state of the planetary rollers having the configuration of FIG. 3 among the side plates.

FIG. 6 is an explanatory diagram showing an example of a pressurizing unit in the speed reducer of FIG.

FIG. 7 is an explanatory diagram showing an example of a pressurizing means in the speed reducer of FIG.

FIG. 8 is an explanatory diagram showing an example of a pressurizing unit in the speed reducer of FIG.

9 is an explanatory view showing an example of a pressurizing means in the speed reducer of FIG.

FIG. 10 is a schematic vertical sectional view showing a speed reducer according to a second embodiment of the present invention.

FIG. 11 is a partial cross-sectional view showing a part of the reducer shown in FIG.

[Explanation of symbols]

 1 ... Friction planetary roller reducer 1a ... Axis 2 ... Housing 3 ... Input shaft 4 ... Output shaft 5 ... Sun roller 5a ... Rolling surface 6 ... Steel Sphere (spherical rolling element) 7, 8 ... Side plate 9 ... Fastening fitting 11 ... Fixed annular member 12 ... Output annular member 11a, 12a ... Tapered surface 14 ... Preload spring 20. ..Friction planetary roller type speed reducer 21 ... Preload springs 51, 52 ... Split type sun roller pieces 51a, 52a ... Tapered surface

Claims (7)

[Claims] 1. A sun roller that rotates integrally with an input shaft, a plurality of spherical rolling elements that are arranged so as to be able to rotate and revolve around the outer peripheral surface of the sun roller as an orbital surface, and these spherical rolling elements as an input shaft. From the side of the sun roller toward the side of the sun roller, a fixed annular member having a tapered inner peripheral surface, a preloading means for applying a preload to the fixed annular member, and for sandwiching and pressing the spherical rolling element. An output annular member having a tapered inner peripheral surface that is in frictional contact with the spherical rolling element from the opposite side of the annular member, an output shaft connected to rotate integrally with the output annular member, and the spherical rolling element. And a rolling element holding means that is sandwiched with a predetermined pressing force from both sides in the axial direction in a state capable of rotating and revolving, and the rolling element holding means has the spherical rolling element from both sides in the axial direction. A pair of side clips A friction planetary roller speed reducer comprising a rate and a pressurizing means that presses these side plates against the spherical rolling elements with a predetermined force. 2. The friction planetary roller speed reducer according to claim 1, wherein the spherical rolling element is a steel ball. 3. The side plate according to claim 1 or 2, wherein the side plate is a plate spring plate elastically deformable in an out-of-plane direction, and the pressing means clamps the side plate with a predetermined force. A friction planetary roller speed reducer, which is a fastening member composed of bolts, nuts, and the like. 4. The pressurizing means according to claim 1 or 2, wherein the pressurizing means includes extension bolts that fasten the pair of side plates, and the extension elasticity of the extension bolts applies a predetermined pressing force to the pair of side plates. A friction planetary roller type speed reducer characterized by being adapted to. 5. The pressurizing means according to claim 1, further comprising an elastic member such as a spring and a wave washer, and the elastic deformation force of the elastic member applies a pressing force to the side plate. Friction planetary roller reducer characterized by 6. A sun roller that rotates integrally with an input shaft, a plurality of spherical rolling elements that are arranged so as to be able to rotate and revolve with the outer peripheral surface of the sun roller as an orbital surface, and these spherical rolling elements. A fixed annular member having a tapered inner peripheral surface that is in frictional contact with the input shaft side, and a tapered inner member that sandwiches the spherical rolling element and is in frictional contact with the spherical rolling element from the opposite side of the fixed annular member. An output annular member having a peripheral surface, and an output shaft connected so as to rotate integrally with the output annular member, wherein the sun roller is of a two-part type divided into an input shaft side and an output shaft side. Rollers, on the outer peripheral surface of these rollers, a tapered raceway surface in which the spherical rolling elements are in frictional contact is formed, the roller on one side is supported movably in the axial direction, By the pressure means, to the side of the spherical rolling element A friction planetary roller reducer characterized by being pressed with a predetermined force. 7. The friction planetary roller reducer according to claim 6, wherein the spherical rolling element is a steel ball.