JPS61103055A - Troidal stepless speed changer - Google Patents

Abstract

PURPOSE:To shorten axial dimension thus to improve the efficiency by arranging the drive shaft and I/O shaft of troidal speed change section in parallel while arranging a speed increase gear train between them. CONSTITUTION:A clutch 3 is provided in the way of drive shaft 2 coupled to an engine 1. Troidal speed change section 5 is constructed with an input disc 6, an output disc 7 and plural rollers 8 the inclination of which is varied to vary the speed change ratio in stepless. Input and output shafts 9, 10 are in parallel with the drive shaft 2 and arranged on non-axial line where the drive shaft 2 and arranged on non-axial line where a pair of speed increase gears 4, 11 gearing each other are fixed respectively to the drive shaft 2 and the input shaft 9. While an advance/back changeover mechanism 14 is arranged between the troidal speed change section 5 and the engine 1.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention is suitable for automotive transmissions, particularly front engine/front drive type or rear engine/rear drive type (hereinafter simply referred to as FF type or RR type) automotive transmissions. The present invention relates to a toroidal continuously variable transmission.

Conventional technology and its problems Conventionally, annular grooves are provided on opposing surfaces of human output disks arranged on the same axis, and a toroidal transmission section is provided in which a plurality of rollers are arranged between circles 1ffi' (?l). A toroidal continuously variable transmission is known in which the gear ratio is variable steplessly by changing the inclination angle of the roller.

In the case of this type of toroidal continuously variable transmission, the rollers contact the annular groove of the input disk (sometimes with a thin oil film) and are driven by friction, and through this roller they contact the annular groove of the output disk. To transmit power, it is necessary to apply thrust (pressure in the axial direction) to the input and output disks in order to apply sufficient contact pressure to the rollers. Unless this thrust is made sufficiently large in accordance with the input torque applied to the input disk, efficient power transmission cannot be achieved.

In other words, the input torque is T, the effective diameter of the input/output disk is R1, the thrust acting on the input/output disk is F, and the traction coefficient between the roller and the annular groove (corresponds to the friction coefficient when there is no oil film). If the relational expression T − < F・μ holds true, the driving force of the input disk is efficiently transmitted to the output disk, but the input torque T increases and the above relational expression no longer holds true. If it disappears, slippage will occur between the roller and the annular groove, and the transmission efficiency will drop significantly. Therefore, as the input torque applied from the engine to the input disk increases, the thrust must be increased accordingly.

However, as the thrust force increases, the contact area between the annular groove and the roller increases, which increases heat generation due to sliding friction, increases transmission loss, and causes problems such as increased wear of the annular groove or the roller. In addition, in order to increase the thrust, the thrust applying means becomes larger, and
The input/output differential and the bearings are required to be strong enough to withstand this thrust, resulting in a problem that the device becomes larger and heavier.

Furthermore, it is generally believed that toroidal continuously variable transmissions are not suitable as transmissions for front-wheel drive or RR-type automobiles, which have limited axial dimensions. The reason for this is that since the engine drive shaft and the input/output shaft of the toroidal transmission section are arranged on the same axis, the axial dimension becomes long, which, together with the axial dimensions of the thrust imparting means and bearing section described above, becomes longer. This is because the axial dimension becomes even longer.

Purpose of the Invention The present invention has been made in view of such conventional problems.
The purpose is to provide a toroidal continuously variable transmission that can reduce the thrust of the input/output disk of the toroidal transmission section to enable efficient power transmission and shorten the axial dimension.

Structure of the Invention In order to achieve the above object, the present invention provides a drive shaft driven by an engine and an input/output shaft of a toroidal transmission section parallel to each other and on a non-axial line, and a distance between the drive shaft and the input shaft is provided. It is equipped with a speed increasing gear train.

In other words, this speed increasing gear train has the function of lowering the input torque from the engine without reducing efficiency, so the input torque applied to the input disk is reduced, and as a result, efficient power transmission is possible with small thrust. In addition, since the drive shaft and the input/output shaft of the toroidal transmission section are arranged in parallel, the axial dimension of the entire device including the engine can be reduced.

DESCRIPTION OF EMBODIMENTS FIG. 1 shows a first embodiment in which a toroidal continuously variable transmission according to the present invention is applied to a front engine/front drive type or a rear engine/rear drive type automobile. A clutch 3 is provided in the middle of the shaft 2 for starting and for intermittent power when switching forward and backward.

As is well known, the toroidal transmission section 5 includes an input disk 6 and an output disk 7 arranged on the same axis, and an annular groove 6a formed on the opposing surfaces of both disks 6.7. It is composed of a plurality of rollers 8 arranged between the input and output disks 6.a and 6.a by changing the inclination of the rollers 8.
The effective diameter of 7 changes, and the gear ratio can be changed steplessly. The above manual disk drive 6 and output disk 7
An input shaft 9 and an output shaft 10 are connected to each of the input and output shafts 9 and 10, and these input and output shafts 9 and 10 are arranged parallel to the drive shaft 2 and off-axis. The above drive shaft 2 and input shaft 9
A pair of speed increasing gears 4 and 11 that mesh with each other are attached to the drive shaft 2, and the driving force of the drive shaft 2 is increased in speed by the speed increasing gears 4 and 11, that is, the torque is reduced and transmitted to the input shaft 9. . In this embodiment, the speed increasing gear train is composed of two speed increasing gears 4.11, but it may be two or more speed increasing gears. Further, an output shaft 10 passes through the input shaft 9 and projects toward the engine l side, and a forward gear 12 and a reverse gear 13 are attached to the ends of the output shaft 10.

A forward/reverse switching mechanism 14 that also serves as a speed reduction mechanism is disposed at an intermediate position between the toroidal transmission section 5 and the engine 1. This forward/reverse switching mechanism 14 is connected to the forward gear 12 and the reverse gear 13. ing. That is, the forward gear 12 directly meshes with the forward gear 16 provided on the reduction shaft 15, while the reverse gear 13 meshes directly with the idle gear 17.
It meshes with a reverse gear 18 provided on the reduction shaft 15 via. The forward gear 16 and the reverse gear 18 are rotatable with respect to the reduction shaft 15, and these gears 16 and 18 are integrally provided with spline gears 16a and 18a. Further, a spline hub 19 fixed to the deceleration shaft 15 is provided at an intermediate position between the forward gear 16 and the reverse gear 18, and the outer periphery of this spline hub 19 and the spline painters 16a and 18a A forward/reverse switching sleeve 20 is slidably engaged with a spline.

A gear 21 is attached to the end of the reduction shaft 15,
This gear 21 is located near the front 1 of the forward/reverse switching mechanism 14.
Near °゛2 position 8fLCL゛45'x7yLy7'J4
It meshes with the gear 23 of the 1b device 221 and transmits power to the axle shaft 24.

In the toroidal continuously variable transmission having the above configuration, the shaft torque of the engine 1 is reduced by the speed increasing gears 4 and 11 and transmitted to the toroidal transmission section 5, so that the reduced torque is applied to the input/output disk 6.7. Even if the thrust is reduced,
No slippage occurs between the rings 116a, 7a and the roller 8. Therefore, transmission loss due to heat generation and wear of the annular groove can be reduced, and the thrust applying means, the input/output disks 6 and 7, and the bearing section can be downsized. Also,
Since the drive shaft 2 and the input/output shaft 9.10 are arranged in parallel and off-axis, the engine 1 and the toroidal transmission section 5
can be brought relatively close to each other, and together with the miniaturization of the thrust applying means and bearing section, it is possible to shorten the axial dimension.

Note that the speed increasing ratio of the speed increasing gears 4 and 11 can be determined as follows. That is, the speed increasing ratio of the speed increasing gear 4゜11 is ρ (<1), and the thrust of the input/output disk 6.7 is F, )
The traction coefficient is μ, the maximum shaft torque of the engine is T7,
If the minimum effective diameter of the input/output disk is RW, the speed increasing ratio ρ may be determined so that the following relationship holds.

FIG. 2 shows a second embodiment of the present invention, in which, unlike the first embodiment, the output shaft 10 of the toroidal transmission section 5 is provided to protrude on the side opposite to the engine 1. A forward gear 12 and a reverse sprocket 13 are attached to the output shaft 10 connected to the output disk 7. The forward gear 12 directly meshes with the forward gear 16 of the forward/reverse switching device 14, and the reverse sprocket 13- is connected to the reverse sprocket 18 via a chain 25. This forward/backward switching mechanism 14
has the same structure as the first embodiment (see FIG. 1), and switches between forward and backward movement by sliding the sleeve 20 in the axial direction.

Effects of the Invention As is clear from the above explanation, according to the present invention, since the speed increasing gear train is provided between the engine and the toroidal transmission section,
The input torque applied to the toroidal transmission section can be reduced, and the thrust of the input/output disk can be kept low accordingly. As a result, transmission loss due to heat generation, etc. can be reduced, wear and tear on the annular groove can be prevented, and the device can be downsized. In addition, since the engine drive shaft and the input/output shaft of the toroidal transmission section are arranged in parallel rather than on the same axis, the clutch and gear mechanism installed between the engine and the toroidal transmission section can be efficiently operated. The axial dimension can be shortened. Therefore, it is possible to provide a transmission suitable for FF or RR type automobiles that have restrictions on axial dimensions.

[Brief explanation of the drawing]

1 and 2 are skeleton diagrams of a first embodiment and a second embodiment of a toroidal continuously variable transmission according to the present invention. DESCRIPTION OF SYMBOLS 1... Engine, 2... Drive shaft, 4, 11... Speed-up gear, 5... Toroidal transmission part, 6... Input disk, 7... Output disk, 6a, 7a... - Annular groove, 8... Roller, 9... Input shaft, 10... Output shaft, 14... Forward/forward switching mechanism, 22... Differential device.

Claims (1)

[Claims] (1) A toroidal type continuously variable transmission equipped with a toroidal transmission section in which annular grooves are provided on opposing surfaces of input and output disks arranged on the same axis, and a plurality of rollers are arranged between the annular grooves. The machine is characterized in that a drive shaft driven by the engine and an input/output shaft of the toroidal transmission section are parallel and non-axial, and a speed increasing gear train is provided between the drive shaft and the input shaft. Toroidal continuously variable transmission.