JP2008215478A - Friction type transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problems of leading to eccentricity of an outer ring such as a drum, reduction in transmission efficiency, generation of vibration, seizure of a roller uncontributing to the transmission and reduction in the service lift of a bearing, since rotary power can be transmitted only by two intermediate rollers in a load state when one intermediate roller does not contribute to the transmission, when the small two intermediate rollers become inverse in the biting-in direction as a wedge, since the drum is eccentrically arranged on an input shaft (a high speed shaft) in a conventional traction type transmission having a wedge roller. <P>SOLUTION: This transmission has the high speed shaft and a low speed shaft rotatably supported in a casing, and is composed of a ring member concentrically arranged with the high speed shaft and a plurality of intermediate rollers abutting on the periphery of the high speed shaft. The transmission shifts a speed by transmitting any of rotation of the ring member and revolution of the intermediate rollers to the low speeds shaft. The wedge roller made to bite in the same direction is respectively interposed between the ring member and the respective intermediate rollers. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to an improvement in a transmission that is used for vehicles, industrial machines, or the like, and that shifts and transmits the driving torque of a high-speed shaft to a low-speed shaft by frictional force.

2. Description of the Related Art Conventionally, as a friction roller type transmission, a so-called traction drive type transmission is known that transmits friction from an input shaft to a rolling element and an output shaft by friction via an oil film on a rolling surface. In particular, torque (tangential force) is required in the traction type transmission, and in order to obtain the tangential force, it is necessary to apply a normal force of about 10 times or more of the tangential force. If the normal force is small, the transmission efficiency decreases, and seizure occurs due to the sliding of the rolling friction surface. As means for securing a normal force to the rolling elements, for example, there are the following methods.
(1) Deflection of ring cross section Utilization of normal force by reducing the inner diameter by pushing the ring of U-shaped cross section from both sides.
(2) Press-in type Manufactured with a press-fitting allowance based on the dimensions of the planetary roller components, and uses the normal force of each part by press-fitting assembly.
(3) Tapered roller A tapered portion is provided on one of the planetary elements to generate a normal force from an axial force.
(4) Deflection of ring diameter Utilization of normal force by the ring circumscribing the roller being bent by tangential force, such as the ring cone RC type.
(5) Wedge roller Eccentric planetary sun roller and provide a wedge roller between the ring and generate normal force.
Among these methods, (1) to (3) are all constant normal forces, and (4) to (5) can obtain normal forces according to torque.

As a traction type transmission device provided with a wedge roller, there are traction roller type transmissions shown in Patent Document 1 and Patent Document 2. These have a structure in which a preload is applied to the contact portion of the wedge roller even in a no-load state by elastically pressing a wedge roller or an intermediate roller such as a wedge roller. With this configuration, it is an object of the present invention to provide a roller transmission that prevents the occurrence of significant slipping at each contact portion even during light load operation and that does not cause damage such as seizure with high efficiency.
JP 2002-013604 A JP 2004-183779 A

  However, in the traction type transmission device provided with the conventional wedge roller, there arises a problem that the transmission efficiency is significantly lowered. This is considered due to the fact that the different diameter space is formed by providing the drum and the like eccentric with respect to the input shaft. Basically, three intermediate rollers are arranged at almost equal intervals, so that a large intermediate roller is arranged at a location where the diameter is maximum, and two small intermediate rollers are arranged at a location where the diameter is narrow. Then, at least one of the two small intermediate rollers is caused to function as a wedge roller.

With such a structure, the direction in which the small two intermediate rollers bite in as wedges is reversed, so that even if one bites in as a wedge roller, the other escapes in a wider diameter direction. Accordingly, one intermediate roller does not contribute to transmission, and in a load state, transmission is performed by two intermediate rollers. In addition, in this state, the outer ring such as a drum is likely to be eccentric, leading to not only a decrease in transmission efficiency, but also a major factor that leads to the occurrence of vibration, the seizure of rollers that do not contribute to the transmission, and the reduction in bearing life.

  Therefore, the present inventor has been able to achieve the present invention as a result of intensive studies in view of the above problems, and the feature thereof is that it has a high speed shaft and a low speed shaft that are rotatably supported by the casing, In a transmission configured by a ring member arranged concentrically with the high-speed shaft and a plurality of intermediate rollers in contact with the periphery of the high-speed shaft, either the rotation of the ring member or the revolution of the intermediate roller is used for the low-speed shaft. And a wedge roller that bites in the same direction between the ring member and each intermediate roller.

  Alternatively, it has a high-speed shaft and a low-speed shaft that are rotatably supported by the casing, and a fixed ring that is fixed concentrically with the high-speed shaft, and a rotation that is disposed at a position facing the fixed ring and connected to the low-speed shaft. A transmission comprising a ring, a plurality of intermediate rollers having a planetary shaft in contact with the periphery of the high-speed shaft, and a carrier that supports the planetary shaft and rotates about the high-speed shaft. A stepped shape, the fixed ring and the rotating ring are shifted by at least one of the different diameters, and a wedge roller is inserted between each intermediate roller, the fixed ring and the rotating ring in the same direction. It is to have done.

  Here, the “intermediate roller” in the present specification refers to a plurality of rollers that are in contact with the peripheral surface of the high-speed shaft and are arranged at almost equal intervals. By transmitting the driving torque from the high-speed shaft to the ring member concentrically with the high-speed shaft via the intermediate roller, rotational torque decelerated from the low-speed shaft due to the rotation of the ring member or the revolution of the intermediate roller is obtained. In the present invention, a wedge roller is interposed between each intermediate roller and the ring member as means for transmitting from the intermediate roller to the ring member. This wedge roller bites between each intermediate roller and the ring member in the same direction (same rotation direction). Even when a load is applied, a very large normal force is evenly applied to the entire rolling system. can do. In addition, by arranging two intermediate rollers so as to sandwich the wedge roller (line symmetric position: a line connecting the center of the high speed axis and the planetary axis), not only forward rotation and reverse rotation, but also the low speed axis is driven and the high speed axis It is equally possible to obtain a speed increaser that obtains high speed rotation.

  The wedge roller may be a spherical ball as well as a cylindrical roller. The diameter of the wedge roller with respect to the gap between the intermediate roller and the ring member is an angle formed by a tangent line connecting the wedge roller, the intermediate roller, and the ring member, that is, a so-called wedge angle of about 6 ° to 22 °. In the traction drive, it is necessary to apply a small normal force to the traction part even in a no-load state, so the wedge roller is pushed in by a biasing means such as a spring or attracted with a magnet (preload, By preloading), when a load is applied from a no-load state, the bite is caused without slipping.

  The “stepped shape of the intermediate roller” means that the rotation and revolution of the intermediate roller are transmitted to a rotating ring arranged at a position opposite to the fixed ring, so that a large gear ratio is output from the low speed shaft connected to the rotating ring. A structure intended for this purpose. For example, when the fixed ring and the rotating ring have the same diameter, a stepped shape intermediate roller with a large diameter on the fixed ring side and a small diameter on the rotating ring side can be arranged at a distance between the fixed ring side and the rotating ring side A large gear ratio can be obtained by interposing wedge rollers having appropriate diameters. In this case, the wedge rollers are arranged so as to sandwich the intermediate rollers.

“The fixed ring and the rotating ring have different diameters” is intended to obtain a large gear ratio as in the case where the intermediate roller has a stepped shape. For example, the gear ratio can be further increased by, for example, setting the fixed ring to have a small diameter and the rotating ring to have a large diameter, and interposing a wedge roller having a diameter corresponding to the distance from the cylindrical intermediate roller. The “stepped shape of the intermediate roller” and “different diameters of the fixed ring and the rotating ring” may be either single structures or a combination of both.

  As described above, the friction transmission according to the present invention can reliably contribute to the transmission of each rotating element by interposing the wedge roller that bites each intermediate roller in the same direction. In particular, since the normal force by the wedge of the wedge roller acts equally on the ring member, all is absorbed inside the rotating body, and no force acts on the bearing, casing, or the like.

In addition, the bearings that support each rotating element do not receive any normal force related to transmission, and have a high speed ratio, high efficiency, high reliability, small size, light weight, and stable speed reduction. Or as a gearbox. In addition, the wedge roller has a slight amount of displacement in the wedge direction and can absorb the machining error of the rotating body, so that high-precision machining is not required and it can be manufactured at low cost.
In addition, by preloading the wedge roller with a magnet, no resistance is generated due to non-contact, it can be provided in a compact manner, and the traction part and traction oil are cleaned by adsorbing fine powder inside the casing. Arise.

The present invention solves the above-mentioned problems by providing a high transmission efficiency associated with a large normal force by providing a wedge roller that acts uniformly on the rotating system in a friction transmission type transmission.

  1 and 2 show an embodiment of a friction transmission 1 according to the present invention. A high-speed shaft 2 that is rotationally driven by a drive source such as an engine or an electric motor, and the periphery of the high-speed shaft 2. Three intermediate rollers 3 that are in contact with each other and rotatably supported, a fixing ring 4 that is concentric with the high-speed shaft 2 and surrounds the intermediate roller 3, and a gap between each intermediate roller 3 and the fixing ring 4 And a wedge roller 5 to be formed. Each intermediate roller 3 is provided on a carrier 32 that rotatably supports the planetary shaft 31, and the carrier 32 is provided with a magnet 6 that attracts each wedge roller 5 in a direction to bite. In this example, the planetary shaft 31 of each intermediate roller 3 is supported so as to be displaceable in the normal direction of the high-speed shaft 2.

In the friction transmission 1, the high-speed shaft 2 that is rotatably supported by a rolling bearing on the casing C is rotationally driven by a motor or the like, so that the intermediate roller 3 that is disposed around and supported by the carrier 32 rotates. . Along with this rotation, a high normal force is generated by the biting of each wedge roller 5 interposed between the fixing ring 4. Each wedge roller 5 rolls along the inner peripheral surface of the fixed ring 4, and decelerated rotation is obtained from the low-speed shaft 7 connected to the carrier 32 of each intermediate roller 3 that revolves. On the contrary, it is possible to drive from the low speed shaft 7 side and output high speed rotation from the high speed shaft 2. In particular, in this example, two wedge rollers 5 are provided so as to sandwich each intermediate roller 3. This is because even when the high-speed shaft 2 is rotated in the reverse direction, the wedge roller 5 can be driven in and driven, and it is possible to cope with the forward and reverse inputs from the low-speed shaft 7 side. In addition to providing two wedge rollers 5 in the axial direction as shown in the figure, one intermediate roller 3 may be arranged in the circumferential direction.

  3A and 3B show another embodiment of the friction transmission 1 according to the present invention, and the intermediate roller 3 has a stepped shape. By making the diameter of the intermediate roller 3 into two types, one is fixed to the fixed ring 4 and the other to the rotating ring 8 and the wedge roller 5 is interposed to roll. Two wedge rollers 5 are arranged so as to be sandwiched between the intermediate rollers 3. In this example, a partition plate 9 is provided between the fixed ring 4 and the rotating ring 8 to prevent the wedge roller 5 from being displaced in the axial direction and from mutual interference. Instead of the partition plate 9, the intermediate roller 3 may be provided with a bowl-shaped portion.

  The friction transmission 1 rotates in the direction opposite to the revolution direction as shown in FIGS. 4A and 4B, as compared with the structure in which the decelerated rotation is output from the revolution of the intermediate roller 3 as in the above-described embodiment. By outputting from the low speed shaft 7 connected to the rotating ring 8, a larger gear ratio can be obtained. As in this example, when the diameter of the fixing ring 4 side of the intermediate roller 3 is increased, the low speed shaft 7 rotates in the revolution direction of the intermediate roller 3.

Although the conventional wedge roller type transmission has a gear ratio of about 1/20 at most, the friction transmission 1 of this example can easily obtain a gear ratio of 1/50 or more. In this method, the smaller the difference in the diameter of the stepped intermediate roller 3, the larger the transmission ratio can be obtained. If the difference in diameter is about 0.2 mm, a transmission ratio of 1/300 or more can be obtained. Is possible. In the second embodiment and the third embodiment to be described later, the high-speed shaft 2 and the low-speed shaft are combined with the structure of the first embodiment by inputting from the low-speed shaft 7 side and outputting the high-speed rotation from the high-speed shaft 2 side. 7 can be made to correspond to the forward / reverse input.
The gear ratio i of the friction transmission 1 of this example is expressed by Equation 1.
When the outer diameter r of the high-speed shaft 2, the inner diameter R of the fixed ring 4 and the rotating ring 8, and the outer diameters D ₁ and D _{2 of the} intermediate roller 3.

FIG. 5 shows still another embodiment of the friction transmission 1 according to the present invention, which has a structure in which the diameter of the rotating ring 8 is larger than that of the fixed ring 4, and the intermediate roller 3 has a stepped shape. As in the case of the above, a large gear ratio can be obtained. In this example, a ball is used as the wedge roller 5, and a groove into which the ball is fitted is provided on the peripheral surface of the intermediate roller 3.
The gear ratio i of the friction transmission 1 of this example is expressed by Equation 2.
When the outer diameter r of the high-speed shaft 2, the inner diameter R ₁ of the fixed ring 4, and the inner diameter R ₂ of the rotating ring 8.

1 is a longitudinal sectional view showing an embodiment of a friction transmission device according to the present invention. (Example 1) FIG. 2 is a transverse cross-sectional view of an intermediate roller portion of the friction transmission shown in FIG. 1. The other examples of the friction-type transmission which concerns on this invention are shown, (a) is a longitudinal cross-sectional view, (b) is a cross-sectional view. (Example 2) (A) is sectional drawing of the rotating ring part of the friction-type transmission shown in FIG. 3, (b) is sectional drawing of a fixed ring part. It is a vertical fragmentary sectional view which shows the further another Example of the friction-type transmission which concerns on this invention. (Example 3)

Explanation of symbols

C casing 1 friction transmission 2 high speed shaft 3 intermediate roller
31 Planetary axis
32 Carrier 4 Fixing ring 5 Wedge roller 6 Magnet 7 Low speed shaft 8 Rotating ring 9 Partition plate

Claims (7)

  A transmission comprising a high-speed shaft and a low-speed shaft rotatably supported by a casing, and a ring member arranged concentrically with the high-speed shaft, and a plurality of intermediate rollers in contact with the periphery of the high-speed shaft, A device that shifts the speed by transmitting either the rotation of the ring member or the revolution of the intermediate roller to the low-speed shaft, and interposing a wedge roller that bites in the same direction between the ring member and each intermediate roller. A friction transmission device characterized by that.   A fixing ring having a high-speed shaft and a low-speed shaft that are rotatably supported by the casing; and a fixed ring concentrically fixed to the high-speed shaft; and a rotating ring disposed at a position facing the fixed ring and connected to the low-speed shaft. A transmission comprising: a plurality of intermediate rollers having a planetary shaft in contact with the periphery of the high-speed shaft; and a carrier that supports the planetary shaft and rotates around the high-speed shaft. A wedge roller that is shifted by at least one of a different shape, the fixed ring and the rotating ring having different diameters, and a wedge roller that digs in the same direction between each intermediate roller, the fixed ring, and the rotating ring. A friction transmission characterized by the above.   The friction transmission according to claim 1 or 2, further comprising an urging unit that presses the wedge roller in a direction to bite it.   4. The friction transmission according to claim 3, wherein the urging means is a magnet.   The friction transmission according to claim 1 or 2, wherein the planetary shaft that supports the intermediate roller is supported so as to be displaceable in a direction normal to the high-speed shaft.   6. The friction transmission according to claim 2, wherein the wedge roller is a cylindrical roller, and a partition plate is provided between the fixed ring and the rotating ring.   6. The friction transmission according to claim 1, wherein the wedge roller is a spherical ball, and a groove into which the ball is fitted is provided on a peripheral surface of the intermediate roller.

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