JP2001012565A - Planetary type transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an axial load applied to a transmission case or a bearing from increasing even when a planetary type transmission is formed of helical gears. SOLUTION: A sun gear bearing 16 is provided to stop the axial motion of a sun gear 3 relative to an output shaft 4. Also, a ring gear bearing 17 is provided to stop the axial motion of a ring gear 7 relative to the output shaft 4. Thus, an axial loads caused by meshing of these gears can be cancelled against each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a planetary transmission, and more particularly to a planetary transmission capable of canceling an axial force generated in the transmission.

[0002]

2. Description of the Related Art As a conventional planetary transmission, for example, as shown in FIG. 2, a sun gear 3 is provided on an input shaft 2 which is mounted on a transmission case 1, and an output shaft is provided on an extension of the input shaft 2. I was wearing 4 The ring gear 7 is held in mesh with the sun gear 3 via a pinion gear 6 which is mounted on a pinion shaft 5 attached to the output shaft 4.

On the other hand, a boss 8a of a ring gear flange 8 provided on a ring gear 7 is externally inserted and held on an output shaft 4, and a pair of clutch gears are sandwiched between a synchro hub 9 which is spline-engaged with the boss 8a. 10,
11 had been arranged. While one clutch gear 10 of the pair of clutch gears 10 and 11 is non-rotatably engaged and held in the transmission case 1, the other clutch gear 11 is splined and held in the output shaft 4. ing.

[0004] By attaching synchro rings 12 and 13 to both clutch gears 10 and 11, respectively, the sleeve 14 meshed and engaged with the synchro hub 9 is moved in the left-right direction in the figure, and the synchro ring 1
The synchro hub 9 is selectively engaged with either one of the clutch gears 10 and 11 via the switches 2 and 13 to switch the speed ratio between the input shaft 2 and the output shaft 4.

[0005] When the planetary transmission having such a configuration is formed by a combination of spur gears, a gear meshing noise is generated, and therefore, there is a limit in reducing the noise level emitted from the transmission. is there.

In order to reduce noise caused by such gear meshing noise, it is effective to configure each gear with a helical gear. However, in this case, an axial load generated between the sun gear 3 and the pinion gear 6 due to the transmission of the torque is transmitted to the input shaft 2 and the output shaft 4 as it is, so that the main pilot bearing that supports the input shaft 2 is used. In addition to the main front bearing (both not shown), a large axial load is applied to the output shaft bearing 15 that supports the output shaft 4.

Therefore, when each gear of the planetary transmission is formed of a helical gear, it is necessary to increase the strength of the bearings and the transmission case 1 to cope with an increase in the load in the axial direction. Another problem is that the weight and manufacturing cost of the transmission increase.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and even when a planetary type transmission is constituted by a helical gear, an axial load applied to the transmission case or each bearing. It is an object of the present invention to provide a planetary transmission that can prevent an increase in the number of transmissions.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a sun gear bearing for preventing relative movement of a sun gear with respect to an output shaft in the axial direction and a relative movement of a ring gear with respect to the output shaft in the axial direction. A ring gear bearing is provided.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a sectional view of a main part showing an embodiment of a planetary transmission according to the present invention. Parts having the same functions as those of the conventional example shown in FIG. 2 are denoted by the same reference numerals, and detailed description thereof will be omitted.

In FIG. 1, a sun gear 3 is provided on an input shaft 2 which is mounted on a transmission case 1.
An output shaft 4 is mounted on an extension of the input shaft 2. A pinion gear 6 is mounted on a carrier 4a formed integrally with the shaft end of the output shaft 4 via a pinion shaft 6, and a ring gear 7 is meshed with the sun gear 3 via the pinion gear 6. Reference numeral 15 denotes an output shaft bearing for attaching the output shaft 4 to the transmission case 1.

On the other hand, a boss 8a of a ring gear flange 8 provided on the ring gear 7 is rotatably held by the output shaft 4, and a synchro hub 9 is spline-engaged with the boss 8a. Further, after a pair of clutch gears 10 and 11 are disposed with the synchro hub 9 interposed therebetween, one clutch gear 10 is engaged with the transmission case 1 so as not to rotate, and the other clutch gear 11 is connected to the output shaft. 4 is spline-engaged. Reference numerals 12 and 13 are synchro rings.

Then, the sleeve 14 meshed and engaged with the synchro hub 9 is moved left and right by a shifter (not shown) to selectively engage the synchro hub 9 with one of the clutch gears 10 and 11. Switching the gear ratio between the input shaft 1 and the output shaft 4 by switching is the same as in the case of the conventional planetary transmission.

In the present invention, the sun gear bearing 16 is sandwiched between both side surfaces of the sun gear 3 and the stepped portion 4b formed on the carrier 4a to prevent the sun gear 3 from moving relative to the output shaft 4 in the axial direction. By interposing a ring gear bearing 17 between the side surface of the ring gear 7 (the inner surface of the ring gear flange 8) and the step 4c of the carrier 4a, relative movement of the ring gear 7 with respect to the output shaft 4 in the axial direction is prevented. ing. In addition, these both bearings 16,
Reference numeral 17 denotes a thrust bearing or the like which has excellent load resistance in the axial direction.

In the planetary transmission having the above-mentioned structure, when the synchro hub 9 is engaged with the clutch gear 10 on the left side in the figure via the sleeve 14, the rotation of the synchro hub 9 is prevented. For this reason, the ring gear flange 8 spline-engaged with the synchro hub 9 does not rotate, and the rotation of the ring gear 7 is prevented. Therefore, in this state, when the input shaft 2 rotates, the pinion gear 6 rotates about the input shaft 2 (output shaft 4) while rotating about the pinion shaft 6, so that the output shaft 4 is To rotate at reduced speed.

On the other hand, when the sync hub 9 is engaged with the clutch gear 11 located on the right side in the figure via the sleeve 14, the rotation of the ring gear 7 is allowed. The ring gear 7 includes a ring gear flange 8, a synchro hub 9,
It is engaged with the output shaft 4 via the sleeve 14 and the clutch gear 14. Therefore, in this case, the rotation of the pinion gear 6 is prevented, and the output shaft 4 rotates at the same speed as the input shaft 2.

For this reason, by selecting which clutch gear 10 or 11 to engage the synchro hub 9, the reduction ratio between the input shaft 2 and the output shaft 4 can be switched and controlled. Such a shifting operation is similar to that of the conventional planetary transmission.

In the case where the sun gear 3, the pinion gear 6 and the ring gear 7 are constituted by helical gears in order to reduce the gear meshing noise in the planetary transmission having the above-mentioned shifting action, the torque between the gears is reduced. It is well known that large axial loads are generated by transmission.

However, the load in the axial direction generated by the sun gear 3 is transmitted to the carrier 4a of the output shaft 4 via the sun gear bearing 16, and the ring gear 7
The axial load generated by the ring gear bearing 17
Is transmitted to the carrier 4a of the output shaft 4 via the Further, since these two loads have the same magnitude and are directed in opposite directions, the loads in the axial direction caused by the meshing of the helical gears are mutually canceled and are not transmitted to the outside.

For this reason, even when a planetary transmission is constituted by a helical gear, not only the main pilot bearing and the main front bearing that support the input shaft 2 but also the output shaft bearing 15 or the shaft that acts on the transmission case 1. There is no increased load in the direction and there is no need to strengthen these parts.

[0021]

As is apparent from the above description, the present invention is designed to cancel the axial force generated in the transmission. Therefore, each gear of the planetary transmission is constituted by helical gears. Even when noise caused by gear meshing noise is reduced, the axial load applied to the transmission case or each bearing does not increase, and there is no need to strengthen these parts. .

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part showing an embodiment of a planetary transmission according to the present invention.

FIG. 2 is a sectional view of a main part showing a conventional example of a planetary transmission.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transmission case 2 Input shaft 3 Sun gear 4 Output shaft 4a Carrier 4b, 4c Step 5 Pinion shaft 6 Pinion gear 7 Ring gear 8 Ring gear flange 8a Boss 9 Synchro hub 10, 11 Clutch gear 12, 13 Synchro cone 14 Sleeve 15 Output shaft Bearing 16 Sun gear bearing 17 Ring gear bearing

Claims (1)

[Claims] 1. A ring gear is arranged coaxially with a sun gear that rotates integrally with an input shaft, and the sun gear and the ring gear are meshed and held via a pinion gear attached to an output shaft arranged coaxially with the input shaft. At the same time, the boss of the ring gear flange provided on the ring gear is externally inserted into the output shaft, and one of a pair of clutch gears arranged with the synchro hub spline-engaged with the boss of the ring gear flange is inserted into the transmission case. The input shaft is selectively engaged with one of the clutch gears via the synchro hub by holding the other clutch gear in spline engagement and holding the other clutch gear with the output shaft. Between the output shaft In a planetary transmission configured to control the transmission ratio, a sun gear bearing that prevents relative movement of the sun gear with respect to the output shaft in the axial direction and a ring gear bearing that prevents relative movement of the ring gear with respect to the output shaft in the axial direction. A planetary transmission, wherein the transmission is provided.