JPH09126286A - Continuously variable transmission for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To mechanically allow the error of a speed change ratio between two sets of belt-type continuously variable speed change mechanisms and to eliminate an accurate speed change control of a belt-type continuously variable speed change mechanism and to avoid increasing the complexity of a control system. SOLUTION: In a continuously variable transmission which has two sets of belt-type continuously variable speed change mechanisms 8, 9 disposed in parallel in the transmission of a vehicle, the belt-type continuously variable speed change mechanisms 8, 9 have the engine side input shafts 8a, 9a in common and connect the wheel side output shafts 8c, 9c to side gears 13b, 13c of a differential gear 13 having a difference limiting mechanism 13a to constitute a transmission in front wheel sides 16, 17 via the ring gear 13d of the differential device 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuously variable transmission for a vehicle installed in a transmission system of a vehicle, and more specifically, a continuously variable transmission for a vehicle in which two sets of belt type continuously variable transmissions are arranged in parallel. Regarding

[0002]

As a continuously variable transmission for a vehicle installed in a transmission system of a vehicle, a drive belt is wound between an input pulley and an output pulley whose pulley groove widths are variably controlled, respectively.
A device having a so-called belt type continuously variable transmission mechanism has been generally known. Further, it has been known that two sets of such belt type continuously variable transmission mechanisms are arranged in parallel to increase the transmission torque capacity (see Japanese Patent Laid-Open No. 61-175361).

Here, in the vehicle continuously variable transmission described in the prior art of Japanese Patent Application Laid-Open No. 61-175361, there are variations in manufacturing and assembling of two belt type continuously variable transmission mechanisms. In order to allow variations in torque transmission characteristics, the input shafts of both belt type continuously variable transmissions are connected via fluid couplings and electromagnetic powder clutches, allowing each input shaft to slip and mutually equalize torque. It is supposed to share.

[0004]

The vehicle continuously variable transmission described in the above prior art also requires a control system for the fluid coupling and the electromagnetic powder clutch, and on top of that, each belt type continuously variable transmission mechanism. It is also necessary to individually and precisely control the gear ratio of 1 and there is a problem that the control system becomes complicated.

Therefore, according to the present invention, even if there is an error in the gear ratio between the belt type continuously variable transmission mechanisms, it is possible to mechanically tolerate this, and there is no need for precise shift control of each belt type continuously variable transmission mechanism. Another object of the present invention is to provide a continuously variable transmission for a vehicle, which can avoid complication of the control system.

[0006]

As a means for achieving this object, the present invention provides a vehicle continuously variable transmission in which two sets of belt type continuously variable transmissions are arranged in parallel in a transmission system of a vehicle. The two sets of belt type continuously variable transmissions have a common input shaft on the engine side, and each output shaft on the wheel side is connected to a side gear of a differential gear, and the wheel is connected via a ring gear of the differential gear. The basic feature is that it is configured to be transmitted to the side.

In the present invention employing such means, the engine power is input in parallel to two sets of belt type continuously variable transmission mechanisms from a common input shaft, and differentially transmitted from the output shafts of each belt type continuously variable transmission mechanism. Input to each side gear of the device. The engine power is transmitted to the wheel side via the ring gear of the differential gear. At this time, even if there is a gear ratio error between the belt type continuously variable transmission mechanisms and there is a rotation difference between the output shafts, the rotation difference is absorbed by the differential device.

When belt slippage or belt breakage occurs in either one of the belt type continuously variable transmission mechanisms, the output shaft of one belt type continuously variable transmission mechanism idles due to the function of the differential device, and the other belt. The power transmission by the CVT is insufficient or impossible. Therefore, in order to avoid such a situation, the present invention is also characterized in that the differential device has a differential limiting function.

Further, in order to make the both belt type continuously variable transmission mechanism correspond to the high rotation of the engine, in the present invention, the common input shaft of the both belt type continuously variable transmission mechanism inputs the engine power through the reduction gear mechanism. It is also characterized by doing.

A dry type single-plate clutch or an electromagnetic clutch is usually provided between the two belt type continuously variable transmission mechanism and the engine. By doubling the capacity, it is possible to interpose a torque converter. Therefore, the present invention is also characterized in that the common input shaft of both belt type continuously variable transmissions inputs the engine power through the torque converter.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be specifically described below with reference to the accompanying drawings. FIG. 1 is a skeleton diagram schematically showing a front wheel drive system which is a transmission system of a vehicle. In the figure, reference numeral 1 is an engine, and reference numeral 2 is a torque connected to a crankshaft 1a of the engine 1 via a drive plate 3. Reference numeral 4 denotes a converter, which is a forward / reverse switching device including a double pinion type planetary gear device 5, a forward clutch 6, a reverse brake 7, and the like.

The torque converter 2 includes a converter cover 2a connected to the drive plate 3, a pump impeller 2b connected to the converter cover 2a, and a turbine runner 2d connected to a turbine shaft 2c as an output shaft.
And a stator 2f rotatably supported on the turbine shaft 2c via a one-way clutch 2e in one direction. A lockup clutch 2g is formed between the converter cover 2a and the turbine shaft 2c. ing.

The double pinion type planetary gear device 5 of the forward / reverse switching device 4 includes a sun gear 5a connected to the turbine shaft 2c of the torque converter 2, a double pinion 5c capable of rolling between the sun gear 5a and the ring gear 5b, and a double pinion 5c. And a carrier 5d for rotatably supporting the pinion 5c. The carrier 5d has a common input shaft 8a of two sets of belt type continuously variable transmissions 8 and 9 arranged in parallel with each other.
It is connected to 9a.

Forward clutch 6 of the forward / reverse switching device 4
Is interposed between the turbine shaft 2c and the carrier 5d,
Due to the engaging action, the double pinion type planetary gear device 5 is integrally fixed to the turbine shaft 2 of the torque converter 2.
The rotational power of c is directly transmitted to the common input shafts 8a and 9a of the belt type continuously variable transmission mechanisms 8 and 9. Further, the reverse brake 7 locks the ring gear 5b by its operation and rotates the carrier 5d in the opposite direction via the double pinion 5c as the sun gear 5a rotates, thereby rotating the turbine shaft 2c of the torque converter 2. The belt type continuously variable transmission mechanism 8 and 9 is inverted and transmitted to the common input shafts 8a and 9a.

The belt type continuously variable transmission mechanisms 8 and 9 are provided with respective input pulleys 8 which rotate integrally with a common input shaft 8a and 9a.
b, 9b, and output pulleys 8 that rotate together with the output shafts 8c, 9c arranged in parallel with the input shafts 8a, 9a.
Drive belts 8e and 9e are respectively wound between d and 9d and have the same specifications. And each input pulley 8b,
A hydraulic servo device 8f, 9f for variably controlling the belt winding radius is attached to 9b, and each output pulley 8 is similarly provided.
Hydraulic servo devices 8g and 9g for variably controlling the belt winding radius are attached to d and 9d.

Hydraulic pressure is supplied to and discharged from the hydraulic servo devices 8f and 9f on the side of the input pulleys 8b and 9b through a shift control valve 11 that operates according to a shift signal from the shift control device 10. Line pressure is constantly supplied to the hydraulic servo devices 8g and 9g on the output pulleys 8d and 9d side through a line pressure control valve 12 that operates according to a line pressure signal from the shift control device 10. Then, the shift control device 10
Via the speed change control valve 11 to the hydraulic servo devices 8f, 9
The supply and discharge of the operating oil pressure to f are controlled, and the belt winding radius of each of the input pulleys 8b and 9b is variably controlled in accordance with the control, whereby the belt type continuously variable transmission mechanisms 8 and 9 perform a gear shift operation. At that time, the output pulleys 8d and 9d clamp the drive belts 8e and 9e according to the line pressure supplied to the hydraulic servo devices 8g and 9g through the line pressure control valve 12,
Ensure a predetermined transmission torque.

Here, the belt type continuously variable transmission mechanism 8, 9
A differential gear 13 having a differential limiting mechanism 13a is interposed between the output pulleys 8d and 9d of each of the side gears 13.
The output shafts 8c and 9c of the belt type continuously variable transmission mechanisms 8 and 9 are connected to b and 13c, respectively. The ring gear 13d of the differential device 13 is connected to the idler shaft 14
Front wheel differential 1 via idler gears 14a, 14b
5 of the ring gear 15a, the left and right front wheels 1 from the side gears 15b and 15c of the front wheel differential device 15.
It is configured to transmit to 6,17.

Next, the operation of the vehicle continuously variable transmission of one embodiment having the above-described structure will be described. Rotational power of the engine 1 is transmitted from the turbine shaft 2c to the sun gear 5a of the double pinion type planetary gear unit 5 in the forward / reverse switching device 4 via the torque converter 2. Here, when the forward clutch 6 is engaged,
The double pinion type planetary gear device 5 is integrally fixed, and the rotational power transmitted to the sun gear 5a is directly transmitted to the common input shafts 8a and 9a of the belt type continuously variable transmission mechanisms 8 and 9 to be in a forward state. Also, reverse brake 7
Is activated, the double pinion type planetary gear device 5
The ring gear 5b is locked, and the rotation of the sun gear 5a is inverted and transmitted to the carrier 5d through the double pinion 5c. The rotational power transmitted to the sun gear 5a is inverted and the belt type continuously variable transmission mechanism 8, 9 common input shafts 8
a, 9a, and thus in the retracted state.

The rotational power transmitted to the common input shafts 8a and 9a of the belt type continuously variable transmission mechanisms 8 and 9 is continuously varied by the belt type continuously variable transmission mechanisms 8 and 9, respectively, and the respective output shafts 8c and 9c. 9c is transmitted. And each output shaft 8c, 9c
The speed change power transmitted to the side gears 13b and 13c of the differential device 13 is input to the output shafts 8c and 9c, respectively.
The differential between them is transmitted to the ring gear 13d of the differential gear 13 in a mechanically allowed state.

Thus, the ring gear 13d of the differential device 13
The speed change power transmitted to the ring gear 15a of the front wheel differential device 15 is transmitted via the idler gears 14a and 14b of the idler shaft 14 to the left and right front wheels 16 and 17 from the side gears 15b and 15c of the front wheel differential device 15. Transmitted.

Here, in the present embodiment, the transmission torque capacity is doubled by arranging the belt type continuously variable transmission mechanisms 8 and 9 in parallel. Therefore, the engine torque is transmitted via the torque converter 2 through the torque converter 2. The large rotational power that is increased and transmitted can also be sufficiently transmitted through the belt type continuously variable transmission mechanisms 8 and 9.

Each output shaft 8 of the belt type continuously variable transmission mechanism 8, 9
c and 9c are side gears 13b and 13 of the differential device 13, respectively.
Since it is connected to c and the differential between them is mechanically allowed,
Even if there is an error in the gear ratio between the belt type continuously variable transmission mechanisms 8 and 9, the error is mechanically absorbed. Therefore,
Since it is no longer necessary to precisely control the shifts of the belt type continuously variable transmissions 8 and 9, the shift control device 10, the shift control valve 11,
It is possible to avoid complication of the shift control system including the line pressure control valve 12 and the like.

Each output shaft 8 of the belt type continuously variable transmission mechanism 8, 9
Since the differential device 13 configured to be transmitted to c and 9c has the differential limiting mechanism 13a, the drive belt 8e (9e) of either one of the belt type continuously variable transmission mechanisms 8 (9) is not slipped or broken. When one of the output shafts 8c (9c) occurs and idles together with the side gear 10b (10c), the idle rotation is blocked by the differential limiting mechanism 10a. Therefore, even if a belt slip or a belt break occurs in any one of the belt type continuously variable transmission mechanisms 8 (9), the speed change power transmitted through the other belt type continuously variable transmission mechanism 9 (8) can be reliably ensured. Can be transmitted to the left and right front wheels 16, 17.

The torque converter 2 in the present embodiment may be replaced by a dry single plate clutch or an electromagnetic clutch. In addition, the belt type continuously variable transmission mechanism 8,
If a reduction gear mechanism is provided in the preceding stage of 9, the rotation speed of the input shafts 8a, 9a of the belt type continuously variable transmission mechanism 8, 9 can be reduced to cope with high-speed engine rotation of, for example, about 7,000 rpm. You can

The continuously variable transmission for a vehicle according to the present invention can be provided not only in the rear wheel drive system of the vehicle but also in the four-wheel drive system.

[0026]

As described above, according to the present invention, the engine power is input in parallel from the common input shaft to the two sets of belt type continuously variable transmission mechanisms, and the difference from the output shaft of each belt type continuously variable transmission mechanism is provided. It is transmitted from the ring gear to the wheel side through each side gear of the moving device. At this time, even if there is a rotation difference between the output shafts of each belt type continuously variable transmission mechanism, the rotation difference is absorbed by the differential device. Therefore, even if there is an error in the gear ratio between the belt type continuously variable transmission mechanisms, this can be mechanically tolerated, and it is possible to eliminate the need for precise shift control of each belt type continuously variable transmission mechanism. It is possible to avoid complication of the system.

Here, when the differential device has a differential limiting function, a belt slip or a belt break occurs in one of the belt type continuously variable transmission mechanisms, and one of the belt type continuously variable transmissions is caused by the function of the differential device. A situation in which the output shaft of the transmission mechanism idles and power transmission by the other belt type continuously variable transmission mechanism is insufficient or impossible can be avoided in advance by the differential limiting function of the differential device.

Further, when the common input shaft of the both belt type continuously variable transmission mechanisms inputs the engine power through the reduction gear mechanism, the both belt type continuously variable transmission mechanisms can be adapted to the high rotation of the engine. it can.

Further, when the common input shaft of both belt type continuously variable transmission mechanisms inputs engine power through the torque converter, both belt type continuously variable transmission mechanisms are arranged in parallel to double the transmission torque capacity. Combined with this, the engine power can be sufficiently transmitted.

[Brief description of the drawings]

FIG. 1 is a skeleton diagram schematically showing a front wheel drive system of a vehicle in which a vehicle continuously variable transmission according to an embodiment of the present invention is provided.

[Explanation of symbols]

 1 engine 1a crankshaft 2 torque converter 2a converter cover 2b pump impeller 2c turbine shaft 2d turbine runner 2e one-way clutch 2f stator 2g lockup clutch 3 drive plate 4 forward / reverse switching device 5 double pinion type planetary gear device 5a sun gear 5b ring gear 5c double pinion 5d carrier 6 forward clutch 7 reverse brake 8 and 9 belt type continuously variable transmission mechanism 8a and 9a input shaft 8b and 9b input pulley 8c and 9c output shaft 8d and 9d output pulley 8e and 9e drive belt 8f and 9f hydraulic servo device 8g, 9g Hydraulic servo device 10 Shift control device 11 Shift control valve 12 Line pressure control valve 13 Differential device 13a Differential limiting mechanism 13b, 13c Side gear 13d Ring gear 14 idler shafts 14a, 14b idler gears 15 front wheel differential gear 15a ring gears 15b, 15c side gears 16, 17 left and right front wheels

Claims (4)

[Claims] 1. A continuously variable transmission for a vehicle in which two sets of belt type continuously variable transmission mechanisms are arranged in parallel in a transmission system of a vehicle, wherein the two sets of belt type continuously variable transmission mechanisms are provided on an engine side. A continuously variable transmission for a vehicle characterized in that the input shaft is common, each output shaft on the wheel side is connected to a side gear of a differential gear, and is transmitted to the wheel side via the ring gear of the differential gear. apparatus. 2. The continuously variable transmission for a vehicle according to claim 1, wherein the differential device has a differential limiting function. 3. The continuously variable transmission for a vehicle according to claim 1, wherein the input shaft inputs engine power through a reduction gear mechanism. 4. The continuously variable transmission for a vehicle according to claim 1, wherein the input shaft inputs engine power through a torque converter.