JPH0989060A - Planet roller type power transmission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a structure properly maintaining a position relation between a sun shaft and a carrier with substantiality in the respect of function and cost, in a planet roller type power transmission device. SOLUTION: In a planet roller type power transmission device including a fixed ring 2, sun shaft 3 concentrically inserted to the internal periphery of this fixed ring 2, a plurality of planet rollers 4 interposed in a manner of press contact between the sun shaft 3 and the fixed ring 2 and a carrier 5 rotated to be synchronized with revolving around of the planet roller 4, a radial type rolling bearing 11 is buried in an end surface of the carrier 5, also a ball 12 of diameter larger than an internal diameter of an inner ring 111 is arranged between the inner ring 111 of this rolling bearing 11 and an end surf ace of the sun shaft 3.

Description

Detailed Description of the Invention

[0001]

[0001] The present invention relates to a planetary roller type power transmission device.

[0002]

2. Description of the Related Art Generally, a planetary roller type power transmission device has, as shown in FIG. 3, a fixed ring 22 fixed to the inner circumference of a housing 21, and a concentric ring inserted into the inner circumference of the fixed ring 22. The sun shaft 23 and the plurality of planetary rollers 24 interposed in a pressure contact state between the sun shaft 23 and the fixed ring 22.
And a carrier 25 that rotates in synchronization with the revolution of the planetary rollers 24.
It is configured to include and.

The sun shaft 23 is formed integrally with a shaft portion 26 which serves as an input shaft or an output shaft. The carrier 25 includes a disc-shaped plate 27, pins 28 that are planted at several circumferential positions near the outer periphery of the plate 27, and the plate 2
7 and a shaft member 29 which is planted at the center of the shaft 7. The shaft member 29 is formed integrally with a shaft portion 30 that serves as an output shaft or an input shaft.

The shaft portion 26 of the sun shaft 23 is the housing 21.
Is supported by the lid 211 of the rolling bearing 31 through the rolling bearing 31, and the shaft member 29 of the carrier 25 is also supported by the housing 21.
It is supported through 2.

In the axial gap between the sun shaft 23 and the carrier 25 in the axial direction, the positional relationship between the two is properly maintained even if a thrust load that may be generated during a gear shifting operation or a thrust load from outside the device is received. However, the balls 33 are interposed for the purpose of reducing the influence of relative rotation due to direct contact between the two. The ball 33 is a conical recess 34 formed on the end surface of the shaft member 29 of the carrier 25.
The sliding contact is made with the flat end surface of the sun shaft 23 in the state of being fitted in.

[0006]

By the way, in the above-mentioned conventional planetary roller type power transmission device, the ball 33 is mounted on the sun shaft 2.
Since it is made to make sliding contact with the end face of No. 3, seizure due to heat generation is likely to occur. As a measure against this,
A method of forming the balls 33 from ceramics can be considered, but it is pointed out that the cost is high. In addition, it is pointed out that the rotating torque increases due to the sliding contact.

On the other hand, as shown in FIG. 4, while the rolling bearing 35 is embedded in the shaft member 29 of the carrier 25, the sun shaft 2
There is one in which a shaft portion 36 is formed at the end portion of 3 and the shaft portion 36 is press-fitted into the inner ring of the rolling bearing 35 to significantly reduce the rotational torque. However, in such a structure, since there is no degree of freedom in centering the rolling bearing 35 and the shaft portion 36 and it is necessary to manage them with high accuracy, the sun shaft 23 and the carrier 25 are attached to the housing 21. In this respect, cost must be increased because the accuracy and the processing accuracy of the sun shaft 23 and the carrier 25 must be controlled with extremely high accuracy.

Therefore, it is an object of the present invention to realize a structure for properly maintaining the positional relationship between the sun shaft and the carrier in the planetary roller power transmission device in terms of function and cost.

[0009]

According to the present invention, a fixed ring, a sun shaft concentrically inserted into the inner periphery of the fixed ring, and a pressure-contact type interposed between the sun shaft and the fixed ring. A planetary roller power transmission device including a plurality of planetary rollers and a carrier that rotates in synchronization with the revolution of the planetary rollers has the following configuration.

In the planetary roller type power transmission device of the present invention, a radial type rolling bearing is embedded in one end surface of either the sun shaft or the carrier, and either the inner ring of the rolling bearing or the sun shaft or the carrier is embedded. A ball having a diameter larger than the inner diameter of the inner ring is arranged between the inner surface and the other end surface.

In the present invention as described above, either the sun shaft or the carrier is integrated with the ball, and the ball is supported by the rolling bearing on either side of the sun shaft or the carrier. That is, the pivot support portion is in rolling contact with the sun shaft and the carrier as if they were pivot support. As a result, wear and heat generation are suppressed and the rotational torque is reduced. As described above, since the ball does not make a sliding contact as in the case of Conventional Example 1, an expensive material such as ceramics is not required, and the ball can be formed of a general steel material.

Further, since the ball is only in contact with the other end surface of the sun shaft or the carrier, the ball can be displaced so as to be in uniform contact with the inner ring of the rolling bearing. That is, since the ball has a self-centering function, the positional relationship between the ball and the rolling bearing is irrelevant to the mounting accuracy of the sun shaft and the carrier to the housing and the processing accuracy of the sun shaft and the carrier. As a result, the manufacturing cost can be reduced.

[0013]

DETAILED DESCRIPTION OF THE INVENTION The details of the present invention will be described below with reference to the embodiments shown in FIGS. FIG. 1 is a vertical sectional side view showing a planetary roller power transmission device according to an embodiment of the present invention.

The planetary roller type power transmission device of the illustrated example has the same basic structure as that described in the conventional example, and includes a fixed ring 2 fixed to the inner circumference of the housing 1 and an inner circumference of the fixed ring 2. The sun shaft 3 inserted concentrically, the sun shaft 3 and the fixed ring 2
A plurality of planet rollers 4 which are interposed in a pressure contact state with the ...
And a carrier 5 that rotates in synchronization with the revolution of the planetary roller 4.

The sun shaft 3 is made of, for example, JIS standard bearing steel (SUJ2) or the like, and is formed integrally with a shaft portion 6 which serves as an input shaft or an output shaft. The carrier 5 is made of, for example, an SAE standard carburizing steel (SAE5120) that has been subjected to normal heat treatment, and has a disk-shaped plate 51.
, Pins 52 ... Planted at several circumferential positions near the outer periphery of the plate 51, and a shaft member 53 planted at the center of the plate 51. The shaft member 53 is formed integrally with the shaft portion 7 that serves as an output shaft or an input shaft.

The shaft 6 which is integral with the sun shaft 3 has a housing 1
The lid 8 is supported by a rolling bearing 9 such as a deep groove type ball bearing, and the shaft member 53 of the carrier 5 is also supported by the housing 1 through a rolling bearing 10 such as a deep groove type ball bearing.

The planetary roller 4 is rotatably supported by the pin 52 of the carrier 5 via a rolling bearing (reference numeral omitted) such as a deep groove type ball bearing.

The characteristic structure of this embodiment is that a cylindrical concave portion 54 is provided on the end surface of the shaft member 53 of the carrier 5, and the concave portion 54 is formed.
The outer circumference of the radial type rolling bearing 11 made of steel is fitted into and embedded by press fitting.
That is, the balls 12 having a diameter larger than the inner diameter of the inner ring 111 are disposed between the inner edge of the inner ring 111 and the end surface of the sun shaft 3 so as to be in contact with each other. The rolling bearing 11 is, for example, a deep groove type ball bearing.

In such a structure, the sun shaft 3 has the ball 1
Since it is integrated with 2 and is rollingly supported by the rolling bearing 11 on the carrier 5 side, it is possible to suppress wear and heat generation and reduce the rotational torque. In this way, the ball 12 does not have a sliding contact unlike the conventional example 1,
It does not require expensive materials such as ceramics, and can be formed of a general steel material such as bearing steel. Therefore, even if the rolling bearing 11 and the steel balls 12 are used, the cost is lower than that of the ceramic balls. Moreover, since the sun shaft 3 is also made of bearing steel, no special processing is required, and wear can be prevented.

Further, since the ball 12 is only in contact with the end surface of the sun shaft 3, the ball 12 can be displaced so as to evenly contact the inner ring 111 of the rolling bearing 11. That is, since the ball 12 has a self-aligning action, the positional relationship between the ball 12 and the rolling bearing 11 is
The mounting accuracy of the sun shaft 3 and the carrier 5 to the housing 1 and the processing accuracy of the sun shaft 3 and the carrier 5 are irrelevant. As a result, the manufacturing cost can be reduced.

The present invention is not limited to the above embodiment, but can also be applied to a multi-speed planetary roller type power transmission device as shown in FIG.

The planetary roller type power transmission device of the illustrated example has a unit structure in which three stages of planetary roller transmissions A, B and C are connected in series inside the housing 1. Each of the planetary roller transmissions A, B, C has a fixed wheel 2 (2A, 2B,
2C), the sun shaft 3 (3A, 3B, 3C), the planet rollers 4 (4A, 4B, 4C), and the carrier 5 (5A, 5C).
B, 5C).

The three-stage planetary roller transmissions A, B,
Of C, the shaft member 53A of the carrier 5A of the planetary roller transmission unit A at the low speed stage (the left stage in the drawing) is the low speed side shaft unit 7A.
The shaft member 53B of the carrier 5B of the planetary roller transmission unit B at the middle speed stage (the middle stage in the drawing) is integrally formed with the sun shaft 3A of the planetary roller transmission unit A at the low speed stage. , The carrier 5 of the planetary roller transmission C at the high speed stage
The C shaft member 53C is formed integrally with the sun shaft 3C of the planetary roller transmission unit B at the medium speed stage.

In this case, the radial type rolling bearings 11 ... Are fitted in the recesses 54 of the shaft members 53A, 53B, 53C of the carriers 5A, 5B, 5C, respectively, and the inner rings of these rolling bearings 11 ... Balls 12 having a diameter larger than the inner diameter of the inner ring 111 are arranged between the inner edge of the inner ring 111 and the end faces of the sun shafts 3A, 3B, 3C, respectively.

In such a multi-speed transmission structure, if the structure between each carrier 5 and each sun shaft 3 is adopted,
More effective. In other words, in the multi-stage shift structure, generally, the mutual positioning accuracy is required to be higher due to the large number of parts, but this can be alleviated. Further, due to the multi-stage shift, the thrust load generated between the carrier 5 and the sun shaft 3 is easily amplified and becomes large, but this can also suppress wear and heat generation between the two.

In the above embodiment, the radial type rolling bearing 11 is embedded in the end surface of the sun shaft 3 instead of the end surface of the shaft member 53 of the carrier 5, and the inner ring 111 of this rolling bearing 11 and the shaft member of the carrier 5 are embedded. A ball 12 having a diameter larger than the inner diameter of the inner ring 111 may be arranged between the end surface 53 and the end surface of 53. In this case, since the strength of the sun shaft 3 tends to be slightly reduced, it can be said that it is preferably applied to a relatively large planetary roller power transmission device.

[0027]

According to the present invention, while the sun shaft and the carrier are supported as if they were pivotally supported, the pivot supporting portion is brought into rolling contact with each other, and the sun shaft and the carrier are provided with a degree of freedom. As a result, it is possible to suppress wear and heat generation and reduce the rotational torque, and it is possible to contribute to cost reduction, for example, because it is not required to have high accuracy in mounting accuracy and processing accuracy of each component.

As described above, it is possible to provide a planetary roller type power transmission device which is excellent in terms of function and cost.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view showing a planetary roller power transmission device according to an embodiment of the present invention.

FIG. 2 is a vertical sectional side view showing a planetary roller power transmission device according to another embodiment of the present invention.

FIG. 3 is a vertical sectional side view of a planetary roller power transmission device of Conventional Example 1.

FIG. 4 is a vertical sectional side view of a planetary roller power transmission device of Conventional Example 2.

[Explanation of symbols]

 1 Housing 2 Fixed Wheel 3 Sun Shaft 4 Planetary Roller 5 Carrier 51 Carrier Plate 52 Carrier Pin 53 Carrier Shaft Member 11 Radial Rolling Bearing 111 Rolling Bearing Inner Ring 12 Ball

Claims (1)

[Claims] 1. A fixed ring, a sun shaft concentrically inserted into the inner periphery of the fixed ring, a plurality of planet rollers interposed in a pressure contact manner between the sun shaft and the fixed ring, and a planet roller. A planetary roller type power transmission device including a carrier that rotates in synchronism with the revolution of a radial type rolling bearing embedded in an end surface of either one of the sun shaft or the carrier, and an inner ring of the rolling bearing. A planetary roller type power transmission device in which a ball having a diameter larger than the inner diameter of the inner ring is disposed between the other end surface of the sun shaft or the carrier.